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Sample records for saturated gel-phase dppc

  1. Lipid bilayers in the gel phase become saturated by triton X-100 at lower surfactant concentrations than those in the fluid phase.

    Science.gov (United States)

    Ahyayauch, Hasna; Collado, M Isabel; Alonso, Alicia; Goñi, Felix M

    2012-06-06

    It has been repeatedly observed that lipid bilayers in the gel phase are solubilized by lower concentrations of Triton X-100, at least within certain temperature ranges, or other nonionic detergents than bilayers in the fluid phase. In a previous study, we showed that detergent partition coefficients into the lipid bilayer were the same for the gel and the fluid phases. In this contribution, turbidity, calorimetry, and 31P-NMR concur in showing that bilayers in the gel state (at least down to 13-20°C below the gel-fluid transition temperature) become saturated with detergent at lower detergent concentrations than those in the fluid state, irrespective of temperature. The different saturation may explain the observed differences in solubilization. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  2. Influence of the interdigitated gel phase in mixtures of ether-linked and monofluorinated ester-linked phospholipids.

    Science.gov (United States)

    Smith, Eric A; Dea, Phoebe K

    2012-12-01

    To evaluate the influence of the hydrocarbon chain linkage on the thermodynamic phase behavior of spontaneously interdigitating lipids, mixtures of ether-linked 1,2-di-O-hexadecyl-phosphocholine (DHPC) and ester-linked 1-palmitoyl-2-[16-fluoropalmitoyl]sn-glycero-3-phosphocholine (F-DPPC) were studied. A combination of differential scanning calorimetry (DSC), fluorescence spectroscopy, and transmittance spectrophotometry was used. Small amounts of F-DPPC increase the pretransition temperature (T(p)) between the interdigitated gel phase (L(β)I) and the ripple gel phase (P(β)'). There are some signs of immiscibility where the non-interdigitated lipid is present in the phase diagram. However, at around 20mol.% F-DPPC, the pretransition merges with the main transition and is no longer detectable as a separate entity. Additionally, the T(m) hysteresis increases steadily with higher mole fractions of F-DPPC. These results support that incorporating F-DPPC progressively stabilizes the L(β)I phase of DHPC until the membrane is fully interdigitated below the main transition temperature (T(m)). The mixtures of F-DPPC and DHPC are miscible once the membrane is entirely interdigitated in the gel phase. Therefore, the ability of both lipids to interdigitate is an important factor controlling gel phase miscibility. Our results also demonstrate that the gel phase behavior of DHPC is highly sensitive to changes in its environment. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. The interdigitated gel phase in mixtures of cationic and zwitterionic phospholipids.

    Science.gov (United States)

    Smith, Eric A; Dea, Phoebe K

    2015-01-01

    To examine the phase behavior of mixtures of zwitterionic and cationic lipids we used three derivatives of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). All three lipids are uniquely capable of spontaneously forming the interdigitated gel phase (LβI) under typical hydration conditions. The P-O-ethyl derivative, 1,2-dipalmitoyl-sn-glycero-3-ethylphosphocholine (EDPPC), was chosen as the cationic lipid. For the zwitterionic lipids, we use the ether-linked 1,2-di-O-hexadecyl-sn-glycero-3-phosphocholine, (DHPC) and the fluorine substituted 1-palmitoyl-2-(16-fluoropalmitoyl)-sn-glycero-3-phosphocholine (F-DPPC). Differential scanning calorimetry (DSC) and fluorescence spectroscopy were used to analyze the lipid mixtures. The F-DPPC/EDPPC mixtures are interdigitated at all lipid ratios below the main transition temperature (Tm). In addition, EDPPC stabilizes the interdigitated gel phase of DHPC until the ripple gel phase (Pβ') is eliminated and only the LβI to liquid crystalline phase (Lα) main transition remains. These results demonstrate that mixtures of cationic and zwitterionic lipids can be compatible with the interdigitated phase. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Resveratrol induces chain interdigitation in DPPC cell membrane model systems.

    Science.gov (United States)

    Longo, Elena; Ciuchi, Federica; Guzzi, Rita; Rizzuti, Bruno; Bartucci, Rosa

    2016-12-01

    Resveratrol is a natural polyphenol found in various plants with potential therapeutic activity as anti-oxidant, anti-inflammatory, cardioprotective and anti-tumoral. Lipid membranes are among cellular components that are targets of its action. In this work ESR of chain labeled lipids, calorimetry, X-ray diffraction and molecular docking are used to study the interaction of resveratrol with membrane model systems of dipalmitoylphosphatidylcholine (DPPC) as a function of resveratrol concentration (0-30 mol% of the lipid) and temperature (10-50°C). Resveratrol incorporated in DPPC bilayers induces considerable motional restriction at the lipid tail termini, removing the gradient of increasing mobility along the chain found in DPPC bilayers in the gel phase. In contrast, it leaves unperturbed the DPPC chain flexibility profile in the liquid-crystalline phase. At low concentration, resveratrol progressively reduces the pre-transition temperature and eliminates the pre-transition for content ≥5mol%. A reduced cooperativity and a downshift of the main transition temperature are observed, especially at high content. The typical diffraction pattern of DPPC multibilayers in the Lβ' phase is converted to a lamellar pattern with reduced d-spacing of untilted lipid chain in a hexagonal packing at 30 mol% of resveratrol. Molecular docking indicates that the energetically favoured anchoring site is the polar headgroup region, where resveratrol acts as a spacer. The overall results are consistent with the formation in DPPC of an interdigitated Lβi gel phase induced by 30 mol% resveratrol. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. A comparative study of the effects of cholesterol and desmosterol on zwitterionic DPPC model membranes.

    Science.gov (United States)

    Altunayar, Cisem; Sahin, Ipek; Kazanci, Nadide

    2015-05-01

    Desmosterol is a direct biosynthetic precursor of cholesterol in Bloch biochemical pathway of cholesterol biosynthesis and differs with cholesterol only by a double bond in carbon 24. In this study, we aimed to research for the first time comparative effects of cholesterol and its precursor desmosterol on dipalmitoyl phosphatidylcholine (DPPC) multilamellar vesicles (MLVs) by utilizing Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). Our DSC studies reveal that with the addition of increasing desmosterol and cholesterol concentrations into pure DPPC MLVs, the pretransition disappears, the main phase transition shifts to lower temperatures and then disappears. While the main phase transition is abolished at 25 mol% concentration of desmosterol, this disappearance of the main phase transition occurs at cholesterol concentration above 30 mol%. Our FTIR studies show that both desmosterol and cholesterol decrease the order in the gel phase, whereas they increase it in the liquid crystalline phase. Importantly, we found that the effect of desmosterol on membrane order is weaker than that of cholesterol in both phases. Moreover, desmosterol and cholesterol increase the dynamics of DPPC membranes in the gel phase, while they decrease it in the liquid crystalline phase. Both sterols also induce a decrease in the wavenumber values of the C=O stretching and PO2(-) antisymmetric double stretching bands of DPPC both in the gel and liquid crystalline phases, which points out hydrogen bonding in between the hydroxyl group of both sterols and the carbonyl and phosphate groups of DPPC membranes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. Disruption of gel phase lipid packing efficiency by sucralose studied with merocyanine 540.

    Science.gov (United States)

    Barker, Morgan; Kennedy, Anthony

    2017-04-01

    Sucralose, an artificial sweetener, displays very different behavior towards membranes than its synthetic precursor sucrose. The impact of both sugars on model dipalmitoylphosphatidylcholine model membranes was investigated using absorbance and flourescence spectroscopy and the membrane probe merocyanine 540. This probe molecule is highly sensitive to changes in membrane packing, microviscosity and polarity. This work focuses on the impact of sugars on the outer leaflet of unilamellar dipalmitoyl phosphatidylcholine model membranes. The choice of lipid permits access to the gel phase at room temperature and incorporation of the dye after liposome formation allows us to examine the direct impact of the sugar on the outer leaflet while maximizing the response of the dye to changes in the bilayer. The results demonstrate that sucrose has no impact on the packing efficiency of lipids in unilamellar DPPC vesicles in the gel phase. Conversely sucralose decreases the packing efficiency of lipids in the gel phase and results in decreased microviscosity and increased membrane fluidity, which may be as a result of water disruption at the membrane water interface. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Reduced graphene oxide directed self-assembly of phospholipid monolayers in liquid and gel phases.

    Science.gov (United States)

    Rui, Longfei; Liu, Jiaojiao; Li, Jingliang; Weng, Yuyan; Dou, Yujiang; Yuan, Bing; Yang, Kai; Ma, Yuqiang

    2015-05-01

    The response of cell membranes to the local physical environment significantly determines many biological processes and the practical applications of biomaterials. A better understanding of the dynamic assembly and environmental response of lipid membranes can help understand these processes and design novel nanomaterials for biomedical applications. The present work demonstrates the directed assembly of lipid monolayers, in both liquid and gel phases, on the surface of a monolayered reduced graphene oxide (rGO). The results from atomic force microscopy indicate that the hydrophobic aromatic plane and the defect holes due to reduction of GO sheets, along with the phase state and planar surface pressure of lipids, corporately determine the morphology and lateral structure of the assembled lipid monolayers. The DOPC molecules, in liquid phase, probably spread over the rGO surface with their tails associating closely with the hydrophobic aromatic plane, and accumulate to form circles of high area surrounding the defect holes on rGO sheets. However, the DPPC molecules, in gel phase, prefer to form a layer of continuous membrane covering the whole rGO sheet including defect holes. The strong association between rGO sheets and lipid tails further influences the melting behavior of lipids. This work reveals a dramatic effect of the local structure and surface property of rGO sheets on the substrate-directed assembly and subsequent phase behavior of the supported lipid membranes. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Changes in wetting properties of silica surface treated with DPPC in the presence of phospholipase A 2 enzyme

    Science.gov (United States)

    Wiącek, Agnieszka Ewa

    2010-10-01

    Wetting properties of silica plates contacted with dipalmitoylphosphatidylcholine (DPPC) or DPPC/enzyme (phospholipase PLA 2) in NaCl solution were determined by thin layer wicking and with a help of Washburn equation. The wicking experiments were performed both for bare plates and the silica plates precontacted overnight with the probe liquid saturated vapors the silica plates, as well as untreated and DPPC (or DPPC/enzyme) treated. Adsorption of DPPC on original silica plates increases a bit hydrophobic character of silica surface in such a way that hydrocarbon chains are directed outwards and the polar part towards the silica surface. However, after the enzyme action the products of DPPC hydrolysis by PLA 2 (palmitic acid and lysophosphatidylcholine) increase again hydrophilic character of silica surface (an increase in acid-base interactions, γsAB). The changes of silica surface wettability are evidently dependent on the time of enzyme contacting with DPPC in NaCl solution. Although, the changes of total surface free energy of silica after treatment with DPPC/enzyme solution are minor about 2-6 mJ/m 2, the changes of the electron-donor ( γs-) and Lifshitz-van der Waals ( γsLW) component of the surface free energy are noticeable. Despite, these results are somehow preliminary, it seems that thin layer wicking method is an interesting tool for investigation of the effect of adsorbed DPPC on hydrophobicity/hydrophilicity of silica surface and influence of enzyme PLA 2 action.

  9. Changes in wetting properties of silica surface treated with DPPC in the presence of phospholipase A{sub 2} enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Wiacek, Agnieszka Ewa, E-mail: a.wiacek@poczta.umcs.lublin.pl [Department of Interfacial Phenomena, Faculty of Chemistry, Maria Curie-Sklodowska University, 20031 Lublin (Poland)

    2010-10-01

    Wetting properties of silica plates contacted with dipalmitoylphosphatidylcholine (DPPC) or DPPC/enzyme (phospholipase PLA{sub 2}) in NaCl solution were determined by thin layer wicking and with a help of Washburn equation. The wicking experiments were performed both for bare plates and the silica plates precontacted overnight with the probe liquid saturated vapors the silica plates, as well as untreated and DPPC (or DPPC/enzyme) treated. Adsorption of DPPC on original silica plates increases a bit hydrophobic character of silica surface in such a way that hydrocarbon chains are directed outwards and the polar part towards the silica surface. However, after the enzyme action the products of DPPC hydrolysis by PLA{sub 2} (palmitic acid and lysophosphatidylcholine) increase again hydrophilic character of silica surface (an increase in acid-base interactions, {gamma}{sub s}{sup AB}). The changes of silica surface wettability are evidently dependent on the time of enzyme contacting with DPPC in NaCl solution. Although, the changes of total surface free energy of silica after treatment with DPPC/enzyme solution are minor about 2-6 mJ/m{sup 2}, the changes of the electron-donor ({gamma}{sub s}{sup -}) and Lifshitz-van der Waals ({gamma}{sub s}{sup LW}) component of the surface free energy are noticeable. Despite, these results are somehow preliminary, it seems that thin layer wicking method is an interesting tool for investigation of the effect of adsorbed DPPC on hydrophobicity/hydrophilicity of silica surface and influence of enzyme PLA{sub 2} action.

  10. Effect of substitution of hydrogen oxide by deuterium oxide on thermotropic transition between the interdigitated gel phase and the ripple phase of dihexadecylphosphatidylcholine

    Energy Technology Data Exchange (ETDEWEB)

    Ohki, K. (Nagoya Univ. (Japan))

    1991-01-15

    Thermotropic transitions of dihexadecylphosphatidylcholine (DHPC) dispersions in hydrogen oxide (1H2O) and deuterium oxide (2H2O) were investigated by differential scanning calorimetry (DSC). In DHPC dispersions, transition temperature between interdigitated gel phase (L beta I) and ripple phase (P beta') is lower in 2H2O than in 1H2O, and transition between the ripple phase (P beta') and fluid phase (L alpha) in 2H2O occurs at a temperature slightly higher than in 1H2O. In dipalmitoylphosphatidylcholine (DPPC) dispersions, on the other hand, transition temperature between lamellar gel phase (L beta') and ripple phase is higher in 2H2O than in 1H2O. These results suggest that the interdigitated gel phase is more stable in 1H2O than in 2H2O. To account for the shift of transition temperature by the water substitution, difference of interfacial energies between these aqueous environments is discussed.

  11. Low concentration of DMSO stabilizes the bilayer gel phase rather than the interdigitated gel phase in dihexadecylphosphatidylcholine membrane.

    Science.gov (United States)

    Yamashita, Y; Kinoshita, K; Yamazaki, M

    2000-08-25

    We have investigated effects of dimethylsulfoxide (DMSO) on the phase stability of multilamellar vesicles of the ether-linked 1,2-dihexadecyl-sn-glycero-3-phosphatidylcholine (DHPC-MLV), which is known to be in the interdigitated gel (LbetaI) phase in excess water at 20 degrees C. The results of X-ray diffraction experiments indicate that the DHPC membrane was in the Lbeta, phase at X> or =0.12 (X=mole fraction of DMSO in DMSO/water mixture). The result of differential scanning calorimetry indicate that the gel to liquid-crystalline phase transition temperature increased, but the LbetaI to Pbeta, phase transition temperature decreased with an increase in DMSO concentration. These results show that DMSO stabilizes the bilayer gel phase rather than the LbetaI phase at its low concentration. The solubility of phosphorylcholine, which is the same structure as the headgroup of DHPC, decreased with an increase in DMSO concentration, indicating that the interaction free energy of the hydrophilic segments of the membrane with solvents increases with an increase in DMSO concentration. On the basis of the thermodynamic analysis, the mechanism of the stabilization of the bilayer gel phase of DHPC-MLV by DMSO is discussed. The decrease in the repulsive interaction between the headgroups of the phospholipid induced by the low concentrations of DMSO in water plays an important role in this stabilization.

  12. Gel phase formation in dilute triblock copolyelectrolyte complexes

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Samanvaya; Andreev, Marat; Levi, Adam E.; Goldfeld, David J.; Mao, Jun; Heller, William T.; Prabhu, Vivek M.; de Pablo, Juan J.; Tirrell, Matthew V.

    2017-02-23

    Assembly of oppositely charged triblock copolyelectrolytes into phase-separated gels at low polymer concentrations (<1% by mass) has been observed in scattering experiments and molecular dynamics simulations. Here we show that in contrast to uncharged, amphiphilic block copolymers that form discrete micelles at low concentrations and enter a phase of strongly interacting micelles in a gradual manner with increasing concentration, the formation of a dilute phase of individual micelles is prevented in polyelectrolyte complexation-driven assembly of triblock copolyelectrolytes. Gel phases form and phase separate almost instantaneously on solvation of the copolymers. Furthermore, molecular models of self-assembly demonstrate the presence of oligo-chain aggregates in early stages of copolyelectrolyte assembly, at experimentally unobservable polymer concentrations. Our discoveries contribute to the fundamental understanding of the structure and pathways of complexation-driven assemblies, and raise intriguing prospects for gel formation at extraordinarily low concentrations, with applications in tissue engineering, agriculture, water purification and theranostics.

  13. Gel phase formation in dilute triblock copolyelectrolyte complexes

    Science.gov (United States)

    Srivastava, Samanvaya; Andreev, Marat; Levi, Adam E.; Goldfeld, David J.; Mao, Jun; Heller, William T.; Prabhu, Vivek M.; de Pablo, Juan J.; Tirrell, Matthew V.

    2017-02-01

    Assembly of oppositely charged triblock copolyelectrolytes into phase-separated gels at low polymer concentrations (block copolymers that form discrete micelles at low concentrations and enter a phase of strongly interacting micelles in a gradual manner with increasing concentration, the formation of a dilute phase of individual micelles is prevented in polyelectrolyte complexation-driven assembly of triblock copolyelectrolytes. Gel phases form and phase separate almost instantaneously on solvation of the copolymers. Furthermore, molecular models of self-assembly demonstrate the presence of oligo-chain aggregates in early stages of copolyelectrolyte assembly, at experimentally unobservable polymer concentrations. Our discoveries contribute to the fundamental understanding of the structure and pathways of complexation-driven assemblies, and raise intriguing prospects for gel formation at extraordinarily low concentrations, with applications in tissue engineering, agriculture, water purification and theranostics.

  14. Lubrication synergy: Mixture of hyaluronan and dipalmitoylphosphatidylcholine (DPPC) vesicles

    DEFF Research Database (Denmark)

    Raj, Akanksha; Wang, Min; Zander, Thomas

    2017-01-01

    with the outer shell of dipalmitoylphophatidylcholine (DPPC) vesicles in bulk solution. Further, we follow adsorption to silica from mixed hyaluronan/DPPC vesicle solution by Quartz Crystal Microbalance with Dissipation measurements. Atomic Force Microscope imaging visualises the adsorbed layer structure...... and partly removed from between the surfaces under high loads. These layers offer very low friction coefficient (

  15. Integration of ganglioside GT1b receptor into DPPE and DPPC phospholipid monolayers: an X-ray reflectivity and grazing-incidence diffraction study.

    Science.gov (United States)

    Miller, C E; Busath, D D; Strongin, B; Majewski, J

    2008-10-01

    Using synchrotron grazing-incidence x-ray diffraction (GIXD) and reflectivity, the in-plane and out-of-plane structures of mixed-ganglioside GT(1b)-phospholipid monolayers were investigated at the air-liquid interface and compared with monolayers of the pure components. The receptor GT(1b) is involved in the binding of lectins and toxins, including botulinum neurotoxin, to cell membranes. Monolayers composed of 20 mol % ganglioside GT(1b), the phospholipid dipalmitoyl phosphatidylethanolamine (DPPE), and the phospholipid dipalmitoyl phosphatidylcholine (DPPC) were studied in the gel phase at 23 degrees C and at surface pressures of 20 and 40 mN/m, and at pH 7.4 and 5. Under these conditions, the two components did not phase-separate, and no evidence of domain formation was observed. The x-ray scattering measurements revealed that GT(1b) was intercalated within the host DPPE/DPPC monolayers, and slightly expanded DPPE but condensed the DPPC matrix. The oligosaccharide headgroups extended normally from the monolayer surfaces into the subphase. This study demonstrated that these monolayers can serve as platforms for investigating toxin membrane binding and penetration.

  16. Adsorption behavior of magnetite nanoparticles into the DPPC model membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Changchun, E-mail: haochangchun@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Li, Junhua; Mu, Wenning; Zhu, Lingqing; Yang, Jiaxiang; Liu, Hongwei [School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Li, Bin [Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences (China); Chen, Shi [School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Sun, Runguang, E-mail: biophymed@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China)

    2016-01-30

    Graphical abstract: A represents the state when DPPC was spread on air/water interface at 5 mN/m surface pressures. DPPC is in the liquid expanded state at the interface. B represents 15 mN/m surface pressures and DPPC monolayer is in the liquid condensed state at the interface. - Highlights: • The adsorption of Fe{sub 3}O{sub 4} nanoparticles on DPPC monolayer has been investigated. • The lifting area/molecule of DPPC monolayers increased with Fe{sub 3}O{sub 4} increasing. • The π–t curves were well fitted by single exponential association equation. • AFM images depended on surface pressure and concentration in subphase. - Abstract: In this report, we have studied the adsorption behavior of Fe{sub 3}O{sub 4} nanoparticles into dipalmitoylphosphatidylcholine (DPPC) monolayer. Adsorption kinetics (π–t) process as well as the surface pressure (π–A) isotherms were monitored by Langmuir Wilhelmy plate. The measurement data indicated the Fe{sub 3}O{sub 4} nanoparticles incorporated into the monolayer at the air–water interface. The lifting area/molecule isotherms of DPPC monolayers increased with the increasing concentration of Fe{sub 3}O{sub 4} in the subphase, however, the values of elasticity reduced. The curves of π–t were well fitted by single exponential association equation. Observation by atomic force microscopy (AFM) on monolayers extracted at 5 mN/m and 15 mN/m suggested that the different interaction of Fe{sub 3}O{sub 4} with DPPC monolayer depended on surface pressure of monolayers and concentration in the subphase. The results of observations were in agreement with the fitted results.

  17. Laser imaging measurements of flow dynamics and mixing in gel-phase flows

    Science.gov (United States)

    Su, Lester K.; Leggett, Jason P.; Coil, Millicent A.

    2010-11-01

    Gelled hypergolic propellants are interesting in rocket propulsion applications, in combining the stability of solid propellants and the controllability of liquid propellants. To exploit these advantages fully, we require an improved understanding of the flow and mixing properties of gel-phase fluids. In this work, we apply planar laser-induced fluorescence (PLIF) to investigate gel mixing in a mixing layer geometry, and particle image velocimetry (PIV) to measure flow velocities in and around two impinging gel streams. We consider both water-based gels (Ultrez 10) and mineral-oil based gels (Kraton G1650) of varying compositions (strengths). For the PLIF, these gels are doped with disodium fluorescein dye. We will discuss some of the issues attendant to the application of these laser diagnostic methods in the gel phase, and we will illustrate how these gel-phase flows differ from flows of Newtonian fluids in similar flow geometries.

  18. Effect of sodium deoxycholate and sodium cholate on DPPC ...

    Indian Academy of Sciences (India)

    Effects of two bile salts, namely sodium deoxycholate (NaDC) and sodium cholate (NaC), on DPPC small unilamellar vesicles have been investigated using the steady-state fluorescence anisotropy () of diphenylhexatriene (DPH) as a tool. It was found that the variation of is sensitive enough to monitor different ...

  19. Effect of sodium deoxycholate and sodium cholate on DPPC vesicles

    Indian Academy of Sciences (India)

    TECS

    monitor different stages of interaction of bile salts with DPPC vesicles. NaDC induced significant changes in the ... more hydrophilic NaC does not interact with the membrane efficiently. Complete solubilisation of phos- pholipids .... the temperature was controlled by circulating water through a jacketted cuvette holder from a ...

  20. Supramolecular gel phase crystallization: orthogonal self-assembly under non-equilibrium conditions.

    Science.gov (United States)

    Kumar, D Krishna; Steed, Jonathan W

    2014-04-07

    This tutorial review charts the history of gel phase crystallization from its origins in Liesegang ring formation to current research in the generation of new pharmaceutical solid forms in low molecular weight organogels. The growth of molecular crystals under a supersaturation gradient within the same space and timescale as the formation of a gel phase material is placed into context as an example of orthogonal self-assembly. Such multi-component, weakly coupled orthogonal self-assembly processes occurring far from equilibrium represent a powerful conceptual paradigm for generating fascinating emergent behaviour in chemical systems.

  1. Rheological model for sol-gel phase transition of thermo-aged heavy oil fractions

    Directory of Open Access Journals (Sweden)

    Xiomara Andrea Vargas Arenas

    2010-01-01

    Full Text Available A power-law rheological model is proposed in this paper: G’’ (ω ∼ ωn and G’ (ω ~ ωn. It represents the increased connectivity between thermo-aged asphalt molecules in a rheo-reactor as one of the applications of systematic rheology. The results confirmed a sol-gel phase transition tendency for aged asphalt in the experimental frequency window at temperatures below 40°C. Such pattern could have been related to the structuring effect arising from the thermo-oxidative asphalt aging process during continuous agitation which has been suitably described by the micellar model of asphalt.

  2. The structural variety of DNA-DPPC-divalent metal cation aggregates: SAXD and SANS study

    Science.gov (United States)

    Uhríková, D.; Pullmannová, P.; Kučerka, N.; Funari, S. S.; Teixeira, J.; Balgavý, P.

    2009-02-01

    We examine the structure of aggregates formed due to DNA interaction with dipalmitoylphosphatidylcholine (DPPC) in presence of Ca2+ and Zn2+ using small-angle synchrotron X-ray diffraction (SAXD) and neutron scattering (SANS). SAXD shows structural heterogeneity as a function of the cation concentration and temperature: At low cation concentration (˜1 mM), aggregates show two DPPC phases, one with a lateral segregation of DNA and cation, while higher cation concentration improves the DNA packing and the condensed lamellar phase is observed in DNA+DPPC+20mMion2+ aggregates. The SANS detected the dissolution of the condensed lamellar phase into unilamellar DPPC+Zn2+ vesicles due to gel ↦ liquid-crystal phase transition in DNA+DPPC+20mM Zn2+ aggregates with the short fragmented salmon sperm DNA.

  3. Low pH induces an interdigitated gel to bilayer gel phase transition in dihexadecylphosphatidylcholine membrane.

    Science.gov (United States)

    Furuike, S; Levadny, V G; Li, S J; Yamazaki, M

    1999-10-01

    We have investigated the influence of pH on the structures and phase behaviors of multilamellar vesicles of the ether-linked dihexadecylphosphatidylcholine (DHPC-MLV). This phospholipid is known to be in the interdigitated gel (L(beta)I) phase in excess water at 20 degrees C at neutral pH. The results of X-ray diffraction experiments indicate that a phase transition from L(beta)I phase to the bilayer gel phase occurred in DHPC-MLV in 0.5 M KCl around pH 3.9 with a decrease in pH, and that at low pH values, less than pH 2.2, DHPC-MLVs were in L(beta') phase. The results of fluorescence and light scattering method indicate that the gel to liquid-crystalline phase transition temperature (T(m)) of DHPC-MLV increased with a decrease in pH. On the basis of a thermodynamic analysis, we conclude that the main mechanism of the low-pH induced L(beta)I to bilayer gel phase transition in DHPC-MLV and the increase in its T(m) is connected with the decrease in the repulsive interaction between the headgroups of these phospholipids. As pH decreases, the phosphate groups of the headgroups begin to be protonated, and as a result, the apparent positive surface charges appear. However, surface dipoles decrease and the interaction free energy of the hydrophilic segments with water increases. The latter effect dominates the pure electrostatic repulsion between the charged headgroups, and thereby, the total repulsive interaction in the interface decreases.

  4. Effects of vitrified and nonvitrified sugars on phosphatidylcholine fluid-to-gel phase transitions.

    Science.gov (United States)

    Koster, K L; Lei, Y P; Anderson, M; Martin, S; Bryant, G

    2000-04-01

    DSC was used to study the ability of glass-forming sugars to affect the gel-to-fluid phase transition temperature, T(m), of several phosphatidylcholines during dehydration. In the absence of sugars, T(m) increased as the lipid dried. Sugars diminished this increase, an effect we explain using the osmotic and volumetric properties of sugars. Sugars vitrifying around fluid phase lipids lowered T(m) below the transition temperature of the fully hydrated lipid, T(o). The extent to which T(m) was lowered below T(o) ranged from 12 degrees to 57 degrees, depending on the lipids' acyl chain composition. Sugars vitrifying around gel phase lipids raised T(m) during the first heating scan in the calorimeter, then lowered it below T(o) in subsequent scans of the sample. Ultrasound measurements of the mechanical properties of a typical sugar-glass indicate that it is sufficiently rigid to hinder the lipid gel-to-fluid transition. The effects of vitrification on T(m) are explained using the two-dimensional Clausius-Clapeyron equation to model the mechanical stress in the lipid bilayer imposed by the glassy matrix. Dextran and polyvinylpyrrolidone (PVP) also vitrified but did not depress T(m) during drying. Hydration data suggest that the large molecular volumes of these polymers caused their exclusion from the interbilayer space during drying.

  5. Topologies, structures and parameter files for lipid simulations in GROMACS with the OPLS-aa force field: DPPC, POPC, DOPC, PEPC, and cholesterol

    Directory of Open Access Journals (Sweden)

    Waldemar Kulig

    2015-12-01

    Full Text Available In this data article we provide topologies and force field parameters files for molecular dynamics simulations of lipids in the OPLS-aa force field using the GROMACS package. This is the first systematic parameterization of lipid molecules in this force field. Topologies are provided for four phosphatidylcholines: saturated DPPC, mono-cis unsaturated POPC and DOPC, and mono-trans unsaturated PEPC. Parameterization of the phosphatidylcholines was achieved in two steps: first, we supplemented the OPLS force field parameters for DPPC with new parameters for torsion angles and van der Waals parameters for the carbon and hydrogen atoms in the acyl chains, as well as new partial atomic charges and parameters for torsion angles in the phosphatidylcholine and glycerol moieties [1]. Next, we derived parameters for the cis and trans double bonds and the neighboring them single bonds [2]. Additionally, we provide GROMACS input files with parameters describing simulation conditions (md.mdp, which are strongly recommended to be used with these lipids models. The data are associated with the research article “Cis and trans unsaturated phosphatidylcholine bilayers: a molecular dynamics simulation study” [2] and provided as supporting materials.

  6. Direct measurement of phase coexistence in DPPC/Cholesterol vesicles using Raman spectroscopy.

    NARCIS (Netherlands)

    de Lange, M.J.L.; Bonn, M.; Müller, M.

    2007-01-01

    The phase behavior of bilayers of binary mixtures of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol has been studied using Raman spectroscopy. It is observed that the shape of the cholesterol vibrational spectrum in lipid-cholesterol binary mixtures does not vary significantly

  7. Effect of gamma irradiation on hyaluronic acid and dipalmitoylphosphatidylcholine (DPPC) interaction

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Ainee Fatimah; Mohd, Hur Munawar Kabir; Taqiyuddin Mawardi bin Ayob, Muhammad; Rosli, Nur Ratasha Alia Md; Mohamed, Faizal; Radiman, Shahidan; Rahman, Irman Abdul [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2014-09-03

    DPPC lipids are the major component constituting the biological membrane, and their importances in various physiological functions are well documented. Hyaluronic acid (HA) in the synovial joint fluid functions as a lubricant, shock absorber and a nutrient carrier. Gamma irradiation has also been found to be effective in depolymerizing and cleaving molecular chains related to free radicals, thus extends with changes in chemical composition as well as its physiological functions. This research are conducted to investigate the hyaluronic acid (HA) and 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) interaction in form of vesicles and its effect to gamma radiation. The size of DPPC vesicles formed via gentle hydration method is between 100 to 200 nm in diameter. HA (0.1, 0.5 and 1.0 mg/ml) was added into the vesicles and characterized by using TEM to determine vesicle size distributions, fusion and rupture of DPPC structure. The results demonstrated that the size of the vesicles approximately between 200 to 300 nm which caused by vesicles fusion with HA and formed even larger vesicles. After being irradiated by 0 to 200 Gy, the size of vesicles decreased as HA was degraded. To elucidate the mechanism of these effects, FTIR spectra were carried out and have shown that at absorption bands at 1700–1750 cm{sup −1} due to formation of carboxylic acid and leads to alteration of HA structure.

  8. Surface tension effects on the phase transition of a DPPC bilayer with and without protein: a molecular dynamics simulation.

    Science.gov (United States)

    Kong, Xian; Qin, Shanshan; Lu, Diannan; Liu, Zheng

    2014-05-14

    While the surface tension of a cell membrane, or a plasma membrane, regulates cell functions, little is known about its effect on the conformational changes of the lipid bilayer and hence the resulting changes in the cell membrane. To obtain some insights into the phase transition of the lipid bilayer as a function of surface tension, we used a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayer as a model lipid bilayer and aquaporin (AqpZ), a transmembrane channel protein for water, as a model embedded protein. A coarse-grained molecular dynamics simulation was applied to illustrate the phase transition behavior of the pure DPPC bilayer and aquaporin-embedded DPPC bilayer under different surface tensions. It was shown that an increased surface tension reduced the phase transition temperature of the DPPC bilayer. As for the DPPC bilayer in gel form, no significant changes occurred in the structure of the bilayer in response to the surface tension. Once in a liquid crystal state, both the structure and properties of the DPPC bilayer, such as area per lipid, lipid order parameters, bilayer thickness and lateral diffusion coefficients, were responsive to the magnitude of surface tension in a linear way. The presence of aquaporin attenuated the compact alignment of the lipid bilayer, hindered the parallel movement, and thus made the DPPC bilayer less sensitive to the surface tension.

  9. Elasticity and phase behavior of DPPC membrane modulated by cholesterol, ergosterol, and ethanol.

    Science.gov (United States)

    Tierney, Kara J; Block, David E; Longo, Marjorie L

    2005-10-01

    Giant vesicles formed of 1,2-dipalmitoylphosphatidylcholine (DPPC) and sterols (cholesterol or ergosterol) in water and water/ethanol solutions have been used to examine the effect of sterol composition and ethanol concentration on the area compressibility modulus (K(a)), overall mechanical behavior, vesicle morphology, and induction of lipid alkyl chain interdigitation. Our results from micropipette aspiration suggest that cholesterol and ergosterol impact the order and microstructure of the gel (L(beta)') phase DPPC membrane. At low concentration (10-15 mol%) these sterols disrupt the long-range lateral order and fluidize the membrane (K(a) approximately 300 mN/m). Then at 18 mol%, these sterols participate in the formation of a continuous cohesive liquid-ordered (L(o)) phase with a sterol-dependent membrane density (K(a) approximately 750 for DPPC/ergosterol and K(a) approximately 1100 mN/m for DPPC/cholesterol). Finally at approximately 40 mol% both cholesterol and ergosterol impart similar condensation to the membrane (K(a) approximately 1200 mN/m). Introduction of ethanol (5-25 vol%) results in drops in the magnitude of K(a), which can be substantial, and sometimes individual vesicles with lowered K(a) reveal two slopes of tension versus apparent area strain. We postulate that this behavior represents disruption of lipid-sterol intermolecular interactions and therefore the membrane becomes interdigitation prone. We find that for DPPC vesicles with sterol concentrations of 20-25 mol%, significantly more ethanol is required to induce interdigitation compared to pure DPPC vesicles; approximately 7 vol% more for ergosterol and approximately 10 vol% more for cholesterol. For lower sterol concentrations (10-15 mol%), interdigitation is offset, but by cells exposed to high concentrations of ethanol and provide evidence that the appearance of the interdigitated (L(beta)I) phase bilayer is a major factor in the disruption of cellular activity, which typically occurs

  10. Penetration and growth of DPPC/DHPC bicelles inside the stratum corneum of the skin.

    Science.gov (United States)

    Barbosa-Barros, L; de la Maza, A; Estelrich, J; Linares, A M; Feliz, M; Walther, P; Pons, R; López, O

    2008-06-03

    The effect of dipalmitoyl phosphatidylcholine (DPPC)/dihexanoyl phosphatidylcholine (DHPC) bicelles on the microstructure of pig stratum corneum (SC) in vitro was evaluated. The physicochemical characterization of these nanoaggregates revealed small disks with diameters around 15 nm and a thickness of 5.4 nm. Upon dilution, the bicelles grow and transform into vesicles. Cryogenic scanning electron microscopy (cryo-SEM) images of the SC pieces treated with this system showed vesicles of about 200 nm and lamellar-like structures in the intercellular lipid areas. These vesicles probably resulted from the growth and molecular rearrangement of the DPPC/DHPC bicelles after penetrating the SC. The presence of lamellar-like structures is ascribed to the interaction of the lipids from bicelles with the SC lipids. The bicellar system used is suitable to penetrate the skin SC and to reinforce the intercellular lipid areas, constituting a promising tool for skin applications.

  11. Limited perturbation of a DPPC bilayer by fluorescent lipid probes: a molecular dynamics study.

    Science.gov (United States)

    Ackerman, David G; Heberle, Frederick A; Feigenson, Gerald W

    2013-05-02

    The properties of lipid bilayer nanometer-scale domains could be crucial for understanding cell membranes. Fluorescent probes are often used to study bilayers, yet their effects on host lipids are not well understood. We used molecular dynamics simulations to investigate perturbations in a fluid DPPC bilayer upon incorporation of three indocarbocyanine probes: DiI-C18:0, DiI-C18:2, or DiI-C12:0. We find a 10-12% decrease in chain order for DPPC in the solvation shell nearest the probe but smaller effects in subsequent shells, indicating that the probes significantly alter only their local environment. We also observe order perturbations of lipids directly across from the probe in the opposite leaflet. Additionally, the DPPC headgroup phosphorus-to-nitrogen vector of lipids nearest the probe exhibits preferential orientation pointing away from the DiI. We show that, while DiI probes perturb their local environment, they do not strongly influence the average properties of "nanoscopic" domains containing a few hundred lipids.

  12. Simultaneous determination of active component and vehicle penetration from F-DPPC liposomes into porcine skin layers.

    Science.gov (United States)

    Mahrhauser, Denise-Silvia; Reznicek, Gottfried; Gehrig, Sebastian; Geyer, Antonia; Ogris, Manfred; Kieweler, Ruth; Valenta, Claudia

    2015-11-01

    Liposomes have been used as innovative delivery vehicles on skin for a number of years due to their positive influence on skin penetration. However, until now it is not entirely clear how and by which mechanism enhancement is achieved. In the present study, the skin permeation of a model substance incorporated into liposomes and a control formulation was compared to study the influence of the vehicle in Franz-type diffusion cell experiments. Furthermore, the penetration depths of both components were studied by simultaneous determination of the active substance and the vehicle component during tape stripping studies and horizontal sectioning. For these purposes we prepared liposomes with 1-palmitoyl-2-(16-fluoropalmitoyl)-sn-glycero-3-phosphocholine (F-DPPC), the monofluorinated analogue of dipalmitoylphosphaditylcholine (DPPC) loaded with sodium fluorescein (SoFl). A sodium-fluorescein solution was used as control formulation. While the semi-solid F-DPPC liposomes and the SoFl-solution performed equally well with similar permeation profiles during skin diffusion experiments, superior penetrated amounts of SoFl into the stratum corneum (SC) from F-DPPC liposomes compared to the SoFl-solution were observed possibly due to a "push" exerted by the vehicle F-DPPC. We also showed that SoFl penetrated through SC into the viable epidermis. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. MAS1H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes.

    Science.gov (United States)

    Mandal, Abhishek; van der Wel, Patrick C A

    2016-11-01

    The lipid bilayer typical of hydrated biological membranes is characterized by a liquid-crystalline, highly dynamic state. Upon cooling or dehydration, these membranes undergo a cooperative transition to a rigidified, more-ordered, gel phase. This characteristic phase transition is of significant biological and biophysical interest, for instance in studies of freezing-tolerant organisms. Magic-angle-spinning (MAS) solid-state NMR (ssNMR) spectroscopy allows for the detection and characterization of the phase transitions over a wide temperature range. In this study we employ MAS 1 H NMR to probe the phase transitions of both solvent molecules and different hydrated phospholipids, including tetraoleoyl cardiolipin (TOCL) and several phosphatidylcholine lipid species. The employed MAS NMR sample conditions cause a previously noted substantial reduction in the freezing point of the solvent phase. The effect on the solvent is caused by confinement of the aqueous solvent in the small and densely packed MAS NMR samples. In this study we report and examine how the freezing point depression also impacts the lipid phase transition, causing a ssNMR-observed reduction in the lipids' melting temperature (T m ). The molecular underpinnings of this phenomenon are discussed and compared with previous studies of membrane-associated water phases and the impact of membrane-protective cryoprotectants. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  14. DPPC Monolayers Exhibit an Additional Phase Transition at High Surface Pressure

    DEFF Research Database (Denmark)

    Shen, Chen; de la Serna, Jorge B.; Struth, Bernd

    2015-01-01

    Pulmonary surfactant forms a monolayer at the air/aqueous interface within the lung. During the breath process, the surface pressure (Π) periodically varies from ~40mN/m up to ~70mN/m. The film is mechanically stable during this rapid and reversible expansion. Pulmonary surfactant consists of ~90......% of lipid with 10% integrated proteins. Among its lipid compounds, di-palmitoyl-phosphatidylcholine (DPPC) dominates (~45wt%). DPPC is the only known lipid that can be compressed to very high surface pressure (~70mN/m) before its monolayer collapses. Most probably, this feature contributes to the mechanical....... Here, we report a second phase transition at elevated surface pressure (~50mN/m). The lateral structure of the monolayer at selected states (8mN/m, 20mN/m, 30mN/m, 40mN/m, 50mN/m, 60mN/m, 70mN/m; covering the whole pressure range of the isotherm) was investigated by grazing incidence X-ray diffraction...

  15. The additional phase transition of DPPC monolayers at high surface pressure confirmed by GIXD study

    DEFF Research Database (Denmark)

    Shen, Chen; Serna, Jorge B. de la; Struth, Bernd

    Pulmonary surfactant forms the alveolar monolayer at the air/aqueous interface within the lung. During the breathing process, the surface pressure periodically varies from ~40mN/m up to ~70mN/m. The film is mechanically stable during this rapid and reversible expansion. The monolayer consists...... of ~90% of lipid with 10% integrated proteins. Among its lipid compounds, di- palmitoyl-phosphatidylcholine (DPPC) dominates (~45wt%). No other lipid but DPPC was so far reported to be compressible to very high surface pressure (~70mN/m) before its monolayer collapsed. Its liquid......-expanded/liquid-condensed (LE/LC) phase transition at ~10mN/m is well known. Here we present results from Langmuir isotherm measurements that evidence a so far not documented second phase transition at elevated surface pressure Π (~50mN/m). The varying lateral structures of the monolayer at 8mN/m, 20mN/m, 30mN/m, 40mN/m, 50m...

  16. Development of lamellar gel phase emulsion containing marigold oil (Calendula officinalis) as a potential modern wound dressing.

    Science.gov (United States)

    Okuma, C H; Andrade, T A M; Caetano, G F; Finci, L I; Maciel, N R; Topan, J F; Cefali, L C; Polizello, A C M; Carlo, T; Rogerio, A P; Spadaro, A C C; Isaac, V L B; Frade, M A C; Rocha-Filho, P A

    2015-04-25

    Appropriate therapeutics for wound treatments can be achieved by studying the pathophysiology of tissue repair. Here we develop formulations of lamellar gel phase (LGP) emulsions containing marigold (Calendula officinalis) oil, evaluating their stability and activity on experimental wound healing in rats. LGP emulsions were developed and evaluated based on a phase ternary diagram to select the best LGP emulsion, having a good amount of anisotropic structure and stability. The selected LGP formulation was analyzed according to the intrinsic and accelerated physical stability at different temperatures. In addition, in vitro and in vivo studies were carried out on wound healing rats as a model. The LGP emulsion (15.0% marigold oil; 10.0% of blend surfactants and 75.0% of purified water [w/w/w]) demonstrated good stability and high viscosity, suggesting longer contact of the formulation with the wound. No cytotoxic activity (50-1000 μg/mL) was observed in marigold oil. In the wound healing rat model, the LGP (15 mg/mL) showed an increase in the leukocyte recruitment to the wound at least on days 2 and 7, but reduced leukocyte recruitment after 14 and 21 days, as compared to the control. Additionally, collagen production was reduced in the LGP emulsion on days 2 and 7 and further accelerated the process of re-epithelialization of the wound itself. The methodology utilized in the present study has produced a potentially useful formulation for a stable LGP emulsion-containing marigold, which was able to improve the wound healing process. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Protection of DPPC phospholipid liposomal membrane against radiation oxidative damage by antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Marathe, D.L.; Pandey, B.N.; Mishra, K.P [Bhabha Atomic Research Centre, Mumbai (India)

    2000-05-01

    Investigations in our laboratory on egg lecithin liposomes have recently showed a marked protection against damage by gamma radiation when cholesterol was present in the composition of vesicles suggesting a role of bilayer molecular architecture in the mechanism of free radical mediated lipid peroxidation. Present study was designed to determine the changes in bilayer permeability in DPPC unilamelar vesicles after exposure to gamma radiation by monitoring the leakage of pre-loaded carboxyfluorescein (CF), a marker loaded in aqueous interior of vesicle and fluidity alterations in the bilayer using fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), a membrane bilayer probe. It was found that radiation doses of an order of magnitude higher were required to produce detectable changes in vesicles of DPPC than in the vesicles of egg lecithin suggesting a modulating role of chemical nature of composition in the membrane radiation sensitivity. It was significant to find that the leakage of CF from and incorporation of DPH into vesicle bilayer showed similar response pattern to radiation doses (0.1-6 kGy) which was also found to be dose rate dependent. Presence of antioxidants; alpha-tocopherol (0.15 mole %) in the bilayer membrane or ascorbic acid (0.1 mM) in the aqueous region significantly protected DPPC vesicles from radiation damage as determined from DPH uptake kinetics suggesting involvement of reactive free radicals of lipids as well as water radicals in the mechanism of membrane peroxidative damage. The magnitude of protection was found to increase with the increasing concentration of both these antioxidants but comparisons showed that {alpha}-tocopherol was far more effective in protecting the vesicles than ascorbic acid. These results contribute to our understanding of the mechanism of radiation oxidative damage and its modification by radical scavenging and/or organizational modulation which emphasize the importance of structure and composition of

  18. Miscibility of dl-α-tocopherol β-glucoside in DPPC monolayer at air/water and air/solid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Neunert, G. [Department of Physics and Biophysics, Poznan University of Life Sciences, 60-637 Poznan (Poland); Makowiecki, J.; Piosik, E.; Hertmanowski, R. [Faculty of Technical Physics, Poznan University of Technology, 60-965 Poznan (Poland); Polewski, K. [Department of Physics and Biophysics, Poznan University of Life Sciences, 60-637 Poznan (Poland); Martynski, T., E-mail: tomasz.martynski@put.poznan.pl [Faculty of Technical Physics, Poznan University of Technology, 60-965 Poznan (Poland)

    2016-10-01

    The role of newly synthesized tocopherol glycosidic derivative in modifying molecular organization and phase transitions of phospholipid monolayer at the air/water interface has been investigated. Two-component Langmuir films of dl-α-tocopheryl β-D-glucopyranoside (BG) mixed with dipalmitoyl phosphatidylcholine (DPPC) in the whole range of mole fractions were formed at the water surface. An analysis of surface pressure versus mean molecular area (π-A) isotherms and Brewster angle microscope images showed that the presence of BG molecules changes the structure and packing of the DPPC monolayer in a BG concentration dependent manner. BG molecules incorporated into DPPC monolayer inhibit its liquid expanded to liquid condensed phase transition proportionally to the BG concentration. The monolayers were also transferred onto solid substrates and visualized using an atomic force microscope. The results obtained indicate almost complete miscibility of BG and DPPC in the monolayers at surface pressures present in the biological cell membrane (30-35·10{sup -3} N·m{sup -1}) for a BG mole fraction as high as 0.3. This makes the monolayer less packed and more disordered, leading to an increased permeability. The results support our previous molecular dynamics simulation data. - Highlights: • Langmuir films of α-tocopherol derivative with DPPC was studied thermodynamically. • Mixed DPPC/BG films were transferred onto mica substrates for topography imaging by using AFM. • Miscibility of BG/DPPC films at surface pressures present in membranes was observed up to MF = 0.3.

  19. Facts about saturated fats

    Science.gov (United States)

    ... fat diary with low-fat or nonfat milk, yogurt, and cheese. Eat more fruits, vegetables, whole grains, and other foods with low or no saturated fat. Alternative Names Cholesterol - saturated fat; Atherosclerosis - saturated fat; Hardening of the ...

  20. Saturated fat (image)

    Science.gov (United States)

    Saturated fat can raise blood cholesterol and can put you at risk for heart disease and stroke. You should ... limit any foods that are high in saturated fat. Sources of saturated fat include whole-milk dairy ...

  1. Effect of Perfluoroalkyl Endgroups on the Interactions of Tri-Block Copolymers with Monofluorinated F-DPPC Monolayers

    Directory of Open Access Journals (Sweden)

    Syed W. H. Shah

    2017-10-01

    Full Text Available We studied the interaction of amphiphilic and triphilic polymers with monolayers prepared from F-DPPC (1-palmitoyl-2-(16-fluoropalmitoyl-sn-glycero-3-phosphocholine, a phospholipid with a single fluorine atom at the terminus of the sn-2 chain, an analogue of dipalmitoyl-phosphatidylcholine (DPPC. The amphiphilic block copolymers contained a hydrophobic poly(propylene oxide block flanked by hydrophilic poly(glycerol monomethacrylate blocks (GP. F-GP was derived from GP by capping both termini with perfluoro-n-nonyl segments. We first studied the adsorption of GP and F-GP to lipid monolayers of F-DPPC. F-GP was inserted into the monolayer up to a surface pressure Π of 42.4 mN m−1, much higher than GP (32.5 mN m−1. We then studied isotherms of lipid-polymer mixtures co-spread at the air-water interface. With increasing polymer content in the mixture a continuous shift of the onset of the liquid-expanded (LE to liquid-condensed (LC transition towards higher molecular and higher area per lipid molecule was observed. F-GP had a larger effect than GP indicating that it needed more space. At a Π-value of 32 mN m−1, GP was excluded from the mixed monolayer, whereas F-GP stayed in F-DPPC monolayers up to 42 mN m−1. F-GP is thus more stably anchored in the monolayer up to higher surface pressures. Images of mixed monolayers were acquired using different fluorescent probes and showed the presence of perfluorinated segments of F-GP at LE-LC domain boundaries.

  2. Phase transition behaviors of the supported DPPC bilayer investigated by sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM).

    Science.gov (United States)

    Wu, Heng-Liang; Tong, Yujin; Peng, Qiling; Li, Na; Ye, Shen

    2016-01-21

    The phase transition behaviors of a supported bilayer of dipalmitoylphosphatidyl-choline (DPPC) have been systematically evaluated by in situ sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM). By using an asymmetric bilayer composed of per-deuterated and per-protonated monolayers, i.e., DPPC-d75/DPPC and a symmetric bilayer of DPPC/DPPC, we were able to probe the molecular structural changes during the phase transition process of the lipid bilayer by SFG spectroscopy. It was found that the DPPC bilayer is sequentially melted from the top (adjacent to the solution) to bottom leaflet (adjacent to the substrate) over a wide temperature range. The conformational ordering of the supported bilayer does not decrease (even slightly increases) during the phase transition process. The conformational defects in the bilayer can be removed after the complete melting process. The phase transition enthalpy for the bottom leaflet was found to be approximately three times greater than that for the top leaflet, indicating a strong interaction of the lipids with the substrate. The present SFG and AFM observations revealed similar temperature dependent profiles. Based on these results, the temperature-induced structural changes in the supported lipid bilayer during its phase transition process are discussed in comparison with previous studies.

  3. Structural transition in aqueous lipid/bile salt [DPPC/NaDC] supramolecular aggregates: SANS and DLS study

    Energy Technology Data Exchange (ETDEWEB)

    Kiselev, M.A. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Janich, M.; Hildebrand, A. [Martin-Luther-University, Halle (Saale) (Germany); Strunz, P. [Berlin Neutron Scattering Center, HZB, Berlin (Germany); Neubert, R.H.H. [Martin-Luther-University, Halle (Saale) (Germany); Lombardo, D., E-mail: lombardo@me.cnr.it [CNR–IPCF, Istituto per i Processi Chimico Fisici – (Sez. Messina), I-98158, Messina (Italy)

    2013-10-16

    Highlights: • Self-assembly in model DPPC lipids and NaDC bile salt by SANS and DLS experiments. • Bile salt creates structural interference against cohesive tendency of DPPC bilayers. • NaDC steric interactions cause transition toward different supramolecular structures. - Abstract: Small angle neutron scattering (SANS) and dynamic light scattering (DLS) were used to study different aggregation states in sodium deoxycholate (NaDC)-phosphatidylcholine systems at T = 60 °C. Size and shape of the aggregates investigated as a function of the NaDC bile salt concentration (at the constant DPPC concentration of 6 mM) indicate a strong dependence of the size and morphology of the generated aggregates on the relative amount of NaDC bile salt. More specifically large occupied area of the bile salt induces a steric interaction which promotes the transition toward a variety of supramolecular structures ranging from ellipsoidal vesicles, ribbon-like structures, up to final spherical mixed micelles at the large amount of bile salt of 10 mM NaDC. The findings of the obtained results give important insight for understanding the formation of different topologies in aqueous lipid–bile salt mixtures as well as stimulate new routes for liposome reconstitution–solubilisation processes suitable for technological applications.

  4. Effect of Melatonin and Cholesterol on the Structure of DOPC and DPPC Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Drolle, E [University of Waterloo, Canada; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Hoopes, M I [University of Waterloo, Canada; Choi, Y [University of Waterloo, Canada; Katsaras, John [ORNL; Karttunen, M [University of Waterloo, Canada; Leonenko, Z [University of Waterloo, Canada

    2013-01-01

    The cell membrane plays an important role in the molecular mechanism of amyloid toxicity associated with Alzheimer's disease. The membrane's chemical composition and the incorporation of small molecules, such as melatonin and cholesterol, can alter its structure and physical properties, thereby affecting its interaction with amyloid peptides. Both melatonin and cholesterol have been recently linked to amyloid toxicity. Melatonin has been shown to have a protective role against amyloid toxicity. However, the underlying molecular mechanism of this protection is still not well understood, and cholesterol's role remains controversial. We used small-angle neutron diffraction (SAND) from oriented lipid multi-layers, small-angle neutron scattering (SANS) from unilamellar vesicles experiments andMolecular Dynamics (MD) simulations to elucidate non-specific interactions of melatonin and cholesterol with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dipalmitoyl-snglycero-3-phosphocholine (DPPC) model membranes. We conclude that melatonin decreases the thickness of both model membranes by disordering the lipid hydrocarbon chains, thus increasing membrane fluidity. This result is in stark contrast to the much accepted ordering effect induced by cholesterol, which causes membranes to thicken.

  5. The additional phase transition of DPPC monolayers at high surface pressure confirmed by GIXD study

    DEFF Research Database (Denmark)

    Shen, Chen; Serna, Jorge B. de la; Struth, Bernd

    -expanded/liquid-condensed (LE/LC) phase transition at ~10mN/m is well known. Here we present results from Langmuir isotherm measurements that evidence a so far not documented second phase transition at elevated surface pressure Π (~50mN/m). The varying lateral structures of the monolayer at 8mN/m, 20mN/m, 30mN/m, 40mN/m, 50m......N/m, 60mN/m, 70mN/m were investigated by grazing incidence X-ray diffraction (GIXD). The results report on the 2D packing lattice with the inter-chain distance dxy. Moreover, the tilt angle of the palmitoyl chains was calculated combining the lattice parameters and the geometrical boundary conditions....... The course of the inter-chain distance versus surface pressure exhibits three regimes, separated by the LE/LC transition and the second phase transition at the higher pressure. This feature may assign a functional task to DPPC in the lung surfactant since it contributes to the mechanical stability...

  6. Fluorescence depolarization analysis of thermal phase transition in DPPC and DMPG aqueous dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Amando Siuiti, E-mail: amandosi@ffclrp.usp.br; Rodrigues, Ana Paula; Moreira Pazin, Wallance; Berardi Barioni, Marina

    2015-02-15

    We performed an overall analysis of steady state, kinetic and dynamical parameters of phospholipids labeled with 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD), to investigate the structural changes accompanying the phase transition of dimyristoyl phosphatidylglycerol (DMPG) vesicles, under low and high ionic strength conditions. For comparison, we also performed experiments on dimyristoyl phosphatidylcholine (DPPC) vesicles, which exhibit a well-defined thermal phase transition. Fluorescence parameters alone (lifetime, pre-exponential factor, rotational correlation times, and initial anisotropy) do not describe the thermal behavior of the vesicles. Combination of intensity decay and anisotropy decay data allows the calculation of mean anisotropy values, and among the several parameters obtained from time-resolved measurements, the main contribution to the mean anisotropy comes from the residual anisotropy, obtained as the limit value at long times. The results of calculations were comparable to the steady state measurements, and allowed the observation of the dependence between the thermal phase transition in DMPG and the ionic strength of the medium. The presence of NaCl affects the lipid packing leading to structural constraints onto the probes that are systematically higher than those observed in low ionic strength. In low ionic strength the long rotational correlation time of the NBD-PE (NBD-phosphatidylethanolamine) probe presents peculiar behavior, showing transient changes along the broad gel–fluid transition, that occurs parallel to the modifications in the scattering intensity. - Highlights: • Time-resolved data were combined to calculate mean values of fluorescence anisotropy. • Fluorescence structural parameters describe lipid vesicles thermal phase transition. • Calculated fluorescence anisotropy describes ionic strength effects in DMPG bilayers.

  7. Strong Static Magnetic Fields Increase the Gel Signal in Partially Hydrated DPPC/DMPC Membranes

    Directory of Open Access Journals (Sweden)

    Jennifer Tang

    2015-09-01

    Full Text Available NIt was recently reported that static magnetic fields increase lipid order in the hydrophobic membrane core of dehydrated native plant plasma membranes [Poinapen, Soft Matter 9:6804-6813, 2013]. As plasma membranes are multicomponent, highly complex structures, in order to elucidate the origin of this effect, we prepared model membranes consisting of a lipid species with low and high melting temperature. By controlling the temperature, bilayers coexisting of small gel and fluid domains were prepared as a basic model for the plasma membrane core. We studied molecular order in mixed lipid membranes made of dimyristoyl-sn-glycero-3-phosphocholine (DMPC and dipalmitoyl-sn-glycero-3-phosphocholine (DPPC using neutron diffraction in the presence of strong static magnetic fields up to 3.5 T. The contribution of the hydrophobic membrane core was highlighted through deuterium labeling the lipid acyl chains. There was no observable effect on lipid organization in fluid or gel domains at high hydration of the membranes. However, lipid order was found to be enhanced at a reduced relative humidity of 43%: a magnetic field of 3.5 T led to an increase of the gel signal in the diffraction patterns of 5%. While all biological materials have weak diamagnetic properties, the corresponding energy is too small to compete against thermal disorder or viscous effects in the case of lipid molecules. We tentatively propose that the interaction between the fatty acid chains’ electric moment and the external magnetic field is driving the lipid tails in the hydrophobic membrane core into a better ordered state.

  8. Design, characterization, and aerosolization of organic solution advanced spray-dried moxifloxacin and ofloxacin dipalmitoylphosphatidylcholine (DPPC) microparticulate/nanoparticulate powders for pulmonary inhalation aerosol delivery

    Science.gov (United States)

    Duan, Jinghua; Vogt, Frederick G; Li, Xiaojian; Hayes, Don; Mansour, Heidi M

    2013-01-01

    The aim of this study was to design and develop respirable antibiotics moxifloxacin (MOXI) hydrochloride and ofloxacin (OFLX) microparticles and nanoparticles, and multifunctional antibiotics particles with or without lung surfactant 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) for targeted dry powder inhalation delivery as a pulmonary nanomedicine. Particles were rationally designed and produced by advanced spray-drying particle engineering from an organic solution in closed mode (no water) from dilute solution. Scanning electron microscopy indicated that these particles had both optimal particle morphology and surface morphology, and the particle size distributions were suitable for pulmonary delivery. Comprehensive and systematic physicochemical characterization and in vitro aerosol dispersion performance revealed significant differences between these two fluoroquinolone antibiotics following spray drying as drug aerosols and as cospray-dried antibiotic drug: DPPC aerosols. Fourier transform infrared spectroscopy and confocal Raman microspectroscopy were employed to probe composition and interactions in the solid state. Spray-dried MOXI was rendered noncrystalline (amorphous) following organic solution advanced spray drying. This was in contrast to spray-dried OFLX, which retained partial crystallinity, as did OFLX:DPPC powders at certain compositions. Aerosol dispersion performance was conducted using inertial impaction with a dry powder inhaler device approved for human use. The present study demonstrates that the use of DPPC offers improved aerosol delivery of MOXI as cospray-dried microparticulate/nanoparticulate powders, whereas residual partial crystallinity influenced aerosol dispersion of OFLX and most of the compositions of OFLX:DPPC inhalation powders. PMID:24092972

  9. Interfacial Water Structure and Cation Binding with the Dppc Phosphate at Air /aqueous Interfaces Studied by Vibrational Sum Frequency Generation Spectroscopy

    Science.gov (United States)

    Hua, Wei; Allen, Heather C.

    2012-06-01

    Molecular-level knowledge of water structure and cation binding specificity to lipid headgroups at lipid/water interfaces plays a key role in many relevant chemical, biological, and environmental processes. To obtain information on the molecular organization at aqueous interfaces, vibrational sum frequency generation (VSFG) has been applied extensively as an interface-specific technique. Dipalmitoylphosphocholine (DPPC) is a major component of cell membranes and has been used as a proxy for the organic coating on fat-coated aerosols. In the present work, in addition to conventional VSFG studies on cation interaction with the phosphate headgroup moiety of DPPC, we employ phase-sensitive vibrational sum frequency generation (PS-VSFG) to investigate the average direction of the transition dipole moment of interfacial water molecules. The average orientation of water structure at DPPC/water interfaces is inferred. DPPC orients interfacial water molecules on average with their net transition dipole moment pointing towards the surface. The influence of Na+, K+, Mg2+, Ca2+ is identified in regard to interfacial water structure and DPPC headgroup organization. Ca2+ is observed to have greater impact on the water structure and a unique binding affinity to the phosphate headgroup relative to other cations tested. In highly concentrated Ca2+ regimes the already disturbed interfacial hydrogen-bonding network reorganizes to resemble that of the neat salt solution interface.

  10. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  11. Investigation into viscoelastic properties of free-standing DPPC lipid bilayer via molecular dynamics and inverse finite element analysis

    Science.gov (United States)

    Momeni Bashusqeh, Saeed; Rastgoo, Abbas

    2017-10-01

    In the current study, the viscoelastic properties of the free-standing DPPC lipid bilayer are investigated using coarse-grained molecular dynamics (CG-MD) and inverse finite element (FE) methods. As the first step, the CG-MD method is employed to simulate the loading/relaxation of a free-standing DPPC lipid bilayer in an indentation experiment. Then the experiment is simulated using the FE method, in which viscoelastic properties of the bilayer are chosen by a genetic algorithm. At each optimization step, the force-time curve is extracted and evaluated with respect to the curve obtained from the CG-MD simulation. The optimization process is continued until a sufficiently good accordance is acquired between the force-time curves obtained from the FE and CG-MD simulations. The material’s behavior in the FE simulation is represented by a two-term Prony model which comprises three unknown constants; the instantaneous Young’s modulus, the steady-state Young’s modulus and the relaxation time constant, which are obtained through optimization. The effects of various simulation parameters, such as indentation speed, the shape of the indenter, the size of the bilayer and temperature, on the viscoelastic properties of the bilayer are also studied and discussed.

  12. Spectral assignment and orientational analysis in a vibrational sum frequency generation study of DPPC monolayers at the air/water interface.

    Science.gov (United States)

    Feng, Rong-Juan; Li, Xia; Zhang, Zhen; Lu, Zhou; Guo, Yuan

    2016-12-28

    The interfacial behavior of the benchmark zwitterionic phospholipid molecule dipalmitoylphosphatidylcholine (DPPC) has been extensively investigated by surface-selective vibrational sum frequency generation spectroscopy (VSFG). However, there is still a lack of agreement between various orientational measurements of phospholipid monolayers at the air/water interface, mainly because of the difficulty in assigning congested VSFG features. In this study, polarization-dependent VSFG measurements reveal a frequency shift between the in-plane and out-of-plane antisymmetric stretching modes of the terminal methyl groups in the DPPC alkyl tails, favoring the model of Cs local symmetry rather than the previously assumed C3v symmetry. Further VSFG experiments of isotopically labeled DPPC successfully capture the vibrational signatures of the glycerol backbone. With the newly derived VSFG polarization selection rules for Cs symmetry and the refreshed spectral assignments, the average tilt angles of the alkyl tail groups, choline headgroup, and glycerol backbone of DPPC molecules can all be determined, showing the powerful capability of VSFG spectroscopy in revealing the structural details at interfaces. The VSFG polarization dependence rules and the orientational analysis procedures developed for Cs symmetry in this work are applicable to other bulky molecules in which the methyl group cannot freely rotate, and they therefore have general applications in future VSFG studies.

  13. Venous oxygen saturation.

    Science.gov (United States)

    Hartog, Christiane; Bloos, Frank

    2014-12-01

    Early detection and rapid treatment of tissue hypoxia are important goals. Venous oxygen saturation is an indirect index of global oxygen supply-to-demand ratio. Central venous oxygen saturation (ScvO2) measurement has become a surrogate for mixed venous oxygen saturation (SvO2). ScvO2 is measured by a catheter placed in the superior vena cava. After results from a single-center study suggested that maintaining ScvO2 values >70% might improve survival rates in septic patients, international practice guidelines included this target in a bundle strategy to treat early sepsis. However, a recent multicenter study with >1500 patients found that the use of central hemodynamic and ScvO2 monitoring did not improve long-term survival when compared to the clinical assessment of the adequacy of circulation. It seems that if sepsis is recognized early, a rapid initiation of antibiotics and adequate fluid resuscitation are more important than measuring venous oxygen saturation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Metamaterial saturable absorber mirror.

    Science.gov (United States)

    Dayal, Govind; Ramakrishna, S Anantha

    2013-02-01

    We propose a metamaterial saturable absorber mirror at midinfrared wavelengths that can show a saturation of absorption with intensity of incident light and switch to a reflecting state. The design consists of an array of circular metallic disks separated by a thin film of vanadium dioxide (VO(2)) from a continuous metallic film. The heating due to the absorption in the absorptive state causes the VO(2) to transit to a metallic phase from the low temperature insulating phase. The metamaterial switches from an absorptive state (R≃0.1%) to a reflective state (R>95%) for a specific threshold intensity of the incident radiation corresponding to the phase transition of VO(2), resulting in the saturation of absorption in the metamaterial. The computer simulations show over 99.9% peak absorbance, a resonant bandwidth of about 0.8 μm at 10.22 μm wavelengths, and saturation intensity of 140 mW cm(-2) for undoped VO(2) at room temperature. We also carried out numerical simulations to investigate the effects of localized heating and temperature distribution by solving the heat diffusion problem.

  15. Saturated and trans fats

    National Research Council Canada - National Science Library

    Shader, Richard I

    2014-01-01

    ... Original Pancake Mix plus ingredients suggested by the recipe: 2 g saturated fat (SF) and no trans fatty acids or trans fat (TFA); bacon, Oscar Mayer Lower Sodium Bacon: 2.5 g SF and no TFA; sausages, Jimmy Dean Original Pork Sausage Links: 8 g SF and no TFA; potatoes, Ore-Ida Mini Tater Tots: 2 g SF and no TFA; and nondairy creamer, Nestlé Coffee-...

  16. Saturation in nuclei

    CERN Document Server

    Lappi, T

    2010-01-01

    This talk discusses some recent studies of gluon saturation in nuclei. We stress the connection between the initial condition in heavy ion collisions and observables in deep inelastic scattering (DIS). The dominant degree of freedom in the small x nuclear wavefunction is a nonperturbatively strong classical gluon field, which determines the initial condition for the glasma fields in the initial stages of a heavy ion collision. A correlator of Wilson lines from the same classical fields, known as the dipole cross section, can be used to compute many inclusive and exclusive observables in DIS.

  17. Towards bio-silicon interfaces: Formation of an ultra-thin self-hydrated artificial membrane composed of dipalmitoylphosphatidylcholine (DPPC) and chitosan deposited in high vacuum from the gas-phase

    Science.gov (United States)

    Retamal, María J.; Cisternas, Marcelo A.; Gutierrez-Maldonado, Sebastian E.; Perez-Acle, Tomas; Seifert, Birger; Busch, Mark; Huber, Patrick; Volkmann, Ulrich G.

    2014-09-01

    The recent combination of nanoscale developments with biological molecules for biotechnological research has opened a wide field related to the area of biosensors. In the last years, device manufacturing for medical applications adapted the so-called bottom-up approach, from nanostructures to larger devices. Preparation and characterization of artificial biological membranes is a necessary step for the formation of nano-devices or sensors. In this paper, we describe the formation and characterization of a phospholipid bilayer (dipalmitoylphosphatidylcholine, DPPC) on a mattress of a polysaccharide (Chitosan) that keeps the membrane hydrated. The deposition of Chitosan (˜25 Å) and DPPC (˜60 Å) was performed from the gas phase in high vacuum onto a substrate of Si(100) covered with its native oxide layer. The layer thickness was controlled in situ using Very High Resolution Ellipsometry (VHRE). Raman spectroscopy studies show that neither Chitosan nor DPPC molecules decompose during evaporation. With VHRE and Atomic Force Microscopy we have been able to detect phase transitions in the membrane. The presence of the Chitosan interlayer as a water reservoir is essential for both DPPC bilayer formation and stability, favoring the appearance of phase transitions. Our experiments show that the proposed sample preparation from the gas phase is reproducible and provides a natural environment for the DPPC bilayer. In future work, different Chitosan thicknesses should be studied to achieve a complete and homogeneous interlayer.

  18. Towards bio-silicon interfaces: Formation of an ultra-thin self-hydrated artificial membrane composed of dipalmitoylphosphatidylcholine (DPPC) and chitosan deposited in high vacuum from the gas-phase

    Energy Technology Data Exchange (ETDEWEB)

    Retamal, María J., E-mail: moretama@uc.cl; Cisternas, Marcelo A.; Seifert, Birger; Volkmann, Ulrich G. [Instituto de Física, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna 4860, 7820436 Santiago (Chile); Centro de Investigación en Nanotecnología y Materiales Avanzados (CIEN-UC), Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna 4860, 7820436 Santiago (Chile); Gutierrez-Maldonado, Sebastian E.; Perez-Acle, Tomas [Computational Biology Lab (DLab), Fundación Ciencia y Vida, Av. Zañartu 1482, Santiago (Chile); Centro Interdisciplinario de Neurociencias de Valparaiso (CINV), Universidad de Valparaiso, Pasaje Harrington 287, Valparaiso (Chile); Busch, Mark; Huber, Patrick [Institute of Materials Physics and Technology, Hamburg University of Technology (TUHH), D-21073 Hamburg-Harburg (Germany)

    2014-09-14

    The recent combination of nanoscale developments with biological molecules for biotechnological research has opened a wide field related to the area of biosensors. In the last years, device manufacturing for medical applications adapted the so-called bottom-up approach, from nanostructures to larger devices. Preparation and characterization of artificial biological membranes is a necessary step for the formation of nano-devices or sensors. In this paper, we describe the formation and characterization of a phospholipid bilayer (dipalmitoylphosphatidylcholine, DPPC) on a mattress of a polysaccharide (Chitosan) that keeps the membrane hydrated. The deposition of Chitosan (∼25 Å) and DPPC (∼60 Å) was performed from the gas phase in high vacuum onto a substrate of Si(100) covered with its native oxide layer. The layer thickness was controlled in situ using Very High Resolution Ellipsometry (VHRE). Raman spectroscopy studies show that neither Chitosan nor DPPC molecules decompose during evaporation. With VHRE and Atomic Force Microscopy we have been able to detect phase transitions in the membrane. The presence of the Chitosan interlayer as a water reservoir is essential for both DPPC bilayer formation and stability, favoring the appearance of phase transitions. Our experiments show that the proposed sample preparation from the gas phase is reproducible and provides a natural environment for the DPPC bilayer. In future work, different Chitosan thicknesses should be studied to achieve a complete and homogeneous interlayer.

  19. Towards bio-silicon interfaces: formation of an ultra-thin self-hydrated artificial membrane composed of dipalmitoylphosphatidylcholine (DPPC) and chitosan deposited in high vacuum from the gas-phase.

    Science.gov (United States)

    Retamal, María J; Cisternas, Marcelo A; Gutierrez-Maldonado, Sebastian E; Perez-Acle, Tomas; Seifert, Birger; Busch, Mark; Huber, Patrick; Volkmann, Ulrich G

    2014-09-14

    The recent combination of nanoscale developments with biological molecules for biotechnological research has opened a wide field related to the area of biosensors. In the last years, device manufacturing for medical applications adapted the so-called bottom-up approach, from nanostructures to larger devices. Preparation and characterization of artificial biological membranes is a necessary step for the formation of nano-devices or sensors. In this paper, we describe the formation and characterization of a phospholipid bilayer (dipalmitoylphosphatidylcholine, DPPC) on a mattress of a polysaccharide (Chitosan) that keeps the membrane hydrated. The deposition of Chitosan (~25 Å) and DPPC (~60 Å) was performed from the gas phase in high vacuum onto a substrate of Si(100) covered with its native oxide layer. The layer thickness was controlled in situ using Very High Resolution Ellipsometry (VHRE). Raman spectroscopy studies show that neither Chitosan nor DPPC molecules decompose during evaporation. With VHRE and Atomic Force Microscopy we have been able to detect phase transitions in the membrane. The presence of the Chitosan interlayer as a water reservoir is essential for both DPPC bilayer formation and stability, favoring the appearance of phase transitions. Our experiments show that the proposed sample preparation from the gas phase is reproducible and provides a natural environment for the DPPC bilayer. In future work, different Chitosan thicknesses should be studied to achieve a complete and homogeneous interlayer.

  20. PLGA/DPPC/trimethylchitosan spray-dried microparticles for the nasal delivery of ropinirole hydrochloride: in vitro, ex vivo and cytocompatibility assessment

    Energy Technology Data Exchange (ETDEWEB)

    Karavasili, Christina [Laboratory of Pharmaceutical Technology, Department of Pharmacy, Aristotle University of Thessaloniki, 54124 (Greece); Bouropoulos, Nikolaos [Department of Materials Science, University of Patras, 26504 Rio, Patras (Greece); Foundation for Research and Technology, Hellas-Institute of Chemical Engineering and High Temperature, P.O. Box 1414, 26504 Patras (Greece); Sygellou, Lamprini [Foundation for Research and Technology, Hellas-Institute of Chemical Engineering and High Temperature, P.O. Box 1414, 26504 Patras (Greece); Amanatiadou, Elsa P.; Vizirianakis, Ioannis S. [Laboratory of Pharmacology, Department of Pharmaceutical Sciences, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Fatouros, Dimitrios G., E-mail: dfatouro@pharm.auth.gr [Laboratory of Pharmaceutical Technology, Department of Pharmacy, Aristotle University of Thessaloniki, 54124 (Greece)

    2016-02-01

    In the present study we investigated polymer-lipid microparticles loaded with ropinirole hydrochloride (RH) for nasal delivery. RH microparticles were further evaluated by means of scanning electron microscopy (SEM), ζ-potential measurements, Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD). In vitro release studies were performed in simulated nasal electrolyte solution (SNES) pH 5.5 at 35 °C. Ex vivo permeation studies were conducted across sheep nasal mucosa. Cytocompatibility was tested in cultured human airway epithelial cells (Calu-3). SEM studies revealed spheroid microparticles in the range of 2.09 μm to 2.41 μm. The presence of trimethylchitosan (TMC) induced a slight shift towards less negative ζ-potential values. Surface chemistry (XPS) revealed the presence of dipalmitoylphospatidylcholine (DPPC) and poly(lactic-co-glycolic acid) (PLGA) onto microparticles' surface, further corroborating the FT-IR and XRD findings. In vitro release studies showed that the microparticle composition can partly modulate the release of RH. Ex vivo studies demonstrated a 2.35-folded enhancement of RH permeation when RH was co-formulated with TMC of low molecular weight, compared to the control. All formulations tested were found to be non-toxic to cells. The results suggest that polymer-lipid microparticles may be a promising carrier for the nasal delivery of RH. - Highlights: • Development of microparticles comprising PLGA/DPPC/TMC for nasal drug delivery. • Physicochemical characterization showed that DPPC dominated microparticles' surface. • Microparticles enhanced permeation of ropinirole across sheep nasal epithelium. • The cytotoxicity assay with Calu-3 cells demonstrated satisfactory cell viability.

  1. Saturated Zone Colloid Transport

    Energy Technology Data Exchange (ETDEWEB)

    H. S. Viswanathan

    2004-10-07

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R{sub col} is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R{sub col} that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k{sub att}, and detachment rate constants, k{sub det}, of colloids to the fracture surface have been measured for the fractured volcanics, and separate R{sub col} uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant

  2. Mechanisms of action of (meth)acrylates in hemolytic activity, in vivo toxicity and dipalmitoylphosphatidylcholine (DPPC) liposomes determined using NMR spectroscopy.

    Science.gov (United States)

    Fujisawa, Seiichiro; Kadoma, Yoshinori

    2012-01-01

    We investigated the quantitative structure-activity relationships between hemolytic activity (log 1/H(50)) or in vivo mouse intraperitoneal (ip) LD(50) using reported data for α,β-unsaturated carbonyl compounds such as (meth)acrylate monomers and their (13)C-NMR β-carbon chemical shift (δ). The log 1/H(50) value for methacrylates was linearly correlated with the δC(β) value. That for (meth)acrylates was linearly correlated with log P, an index of lipophilicity. The ipLD(50) for (meth)acrylates was linearly correlated with δC(β) but not with log P. For (meth)acrylates, the δC(β) value, which is dependent on the π-electron density on the β-carbon, was linearly correlated with PM3-based theoretical parameters (chemical hardness, η; electronegativity, χ; electrophilicity, ω), whereas log P was linearly correlated with heat of formation (HF). Also, the interaction between (meth)acrylates and DPPC liposomes in cell membrane molecular models was investigated using (1)H-NMR spectroscopy and differential scanning calorimetry (DSC). The log 1/H(50) value was related to the difference in chemical shift (ΔδHa) (Ha: H (trans) attached to the β-carbon) between the free monomer and the DPPC liposome-bound monomer. Monomer-induced DSC phase transition properties were related to HF for monomers. NMR chemical shifts may represent a valuable parameter for investigating the biological mechanisms of action of (meth)acrylates.

  3. Brine Distribution after Vacuum Saturation

    DEFF Research Database (Denmark)

    Hedegaard, Kathrine; Andersen, Bertel Lohmann

    1999-01-01

    Experiments with the vacuum saturation method for brine in plugs of chalk showed that a homogeneous distribution of brine cannot be ensured at saturations below 20% volume. Instead of a homogeneous volume distribution the brine becomes concentrated close to the surfaces of the plugs...

  4. Misconceptions in Reporting Oxygen Saturation

    NARCIS (Netherlands)

    Toffaletti, John; Zijlstra, Willem G.

    2007-01-01

    BACKGROUND: We describe some misconceptions that have become common practice in reporting blood gas and cooximetry results. In 1980, oxygen saturation was incorrectly redefined in a report of a new instrument for analysis of hemoglobin (Hb) derivatives. Oxygen saturation (sO(2)) was redefined as the

  5. Saturation current spikes eliminated in saturable core transformers

    Science.gov (United States)

    Schwarz, F. C.

    1971-01-01

    Unsaturating composite magnetic core transformer, consisting of two separate parallel cores designed so impending core saturation causes signal generation, terminates high current spike in converter primary circuit. Simplified waveform, demonstrates transformer effectiveness in eliminating current spikes.

  6. Refined OPLS All-Atom Force Field for Saturated Phosphatidylcholine Bilayers at Full Hydration

    DEFF Research Database (Denmark)

    Maciejewski, A.; Pasenkiewicz-Gierula, M.; Cramariuc, O.

    2014-01-01

    We report parametrization of dipalmitoyl-phosphatidylcholine (DPPC) in the framework of the Optimized Parameters for Liquid Simulations all-atom (OPLS-AA) force field. We chose DPPC as it is one of the most studied phospholipid species and thus has plenty of experimental data necessary for model ...

  7. Theory of graphene saturable absorption

    Science.gov (United States)

    Marini, A.; Cox, J. D.; García de Abajo, F. J.

    2017-03-01

    Saturable absorption is a nonperturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a semianalytical nonperturbative single-particle approach, describing electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics nonperturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. We obtain results in qualitative agreement with atomistic quantum-mechanical simulations of graphene nanoribbons including electron-electron interactions, finite-size, and higher-band effects. Remarkably, such effects are found to affect mainly the linear absorption, while the predicted saturation intensities are in good quantitative agreement in the limit of extended graphene. Additionally, we find that the modulation depth of saturable absorption in graphene can be electrically manipulated through an externally applied gate voltage. Our results are relevant for the development of graphene-based optoelectronic devices, as well as for applications in mode-locking and random lasers.

  8. Saturation of the turbulent dynamo.

    Science.gov (United States)

    Schober, J; Schleicher, D R G; Federrath, C; Bovino, S; Klessen, R S

    2015-08-01

    The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed fields via turbulent motions on small spatial scales and subsequently transporting the magnetic energy to larger scales. This process is known as the turbulent dynamo and depends on the properties of turbulence, i.e., on the hydrodynamical Reynolds number and the compressibility of the gas, and on the magnetic diffusivity. While we know the growth rate of the magnetic energy in the linear regime, the saturation level, i.e., the ratio of magnetic energy to turbulent kinetic energy that can be reached, is not known from analytical calculations. In this paper we present a scale-dependent saturation model based on an effective turbulent resistivity which is determined by the turnover time scale of turbulent eddies and the magnetic energy density. The magnetic resistivity increases compared to the Spitzer value and the effective scale on which the magnetic energy spectrum is at its maximum moves to larger spatial scales. This process ends when the peak reaches a characteristic wave number k☆ which is determined by the critical magnetic Reynolds number. The saturation level of the dynamo also depends on the type of turbulence and differs for the limits of large and small magnetic Prandtl numbers Pm. With our model we find saturation levels between 43.8% and 1.3% for Pm≫1 and between 2.43% and 0.135% for Pm≪1, where the higher values refer to incompressible turbulence and the lower ones to highly compressible turbulence.

  9. Slow light in saturable absorbers

    OpenAIRE

    Macke, Bruno; Ségard, Bernard

    2008-01-01

    International audience; In connection with the experiments recently achieved on doped crystals, biological samples, doped optical fibers and semiconductor heterostructures, we revisit the theory of the propagation of a pulse-modulated light in a saturable absorber. Explicit analytical expressions of the transmitted pulse are obtained, enabling us to determine the parameters optimizing the time-delay of the transmitted pulse with respect to the incident pulse. We finally compare the maximum fr...

  10. Saturation of Van Allen's belts

    CERN Document Server

    Le Bel, E

    2002-01-01

    The maximum number of electrons that can be trapped in van Allen's belts has been evaluated at CEA-DAM more precisely than that commonly used in the space community. The modelization that we have developed allows to understand the disagreement (factor 50) observed between the measured and predicted electrons flux by US satellites and theory. This saturation level allows sizing-up of the protection on a satellite in case of energetic events. (authors)

  11. Transition to Turbulent Dynamo Saturation

    Science.gov (United States)

    Seshasayanan, Kannabiran; Gallet, Basile; Alexakis, Alexandros

    2017-11-01

    While the saturated magnetic energy is independent of viscosity in dynamo experiments, it remains viscosity dependent in state-of-the-art 3D direct numerical simulations (DNS). Extrapolating such viscous scaling laws to realistic parameter values leads to an underestimation of the magnetic energy by several orders of magnitude. The origin of this discrepancy is that fully 3D DNS cannot reach low enough values of the magnetic Prandtl number Pm. To bypass this limitation and investigate dynamo saturation at very low Pm, we focus on the vicinity of the dynamo threshold in a rapidly rotating flow: the velocity field then depends on two spatial coordinates only, while the magnetic field consists of a single Fourier mode in the third direction. We perform numerical simulations of the resulting set of reduced equations for Pm down to 2 ×10-5. This parameter regime is currently out of reach to fully 3D DNS. We show that the magnetic energy transitions from a high-Pm viscous scaling regime to a low-Pm turbulent scaling regime, the latter being independent of viscosity. The transition to the turbulent saturation regime occurs at a low value of the magnetic Prandtl number, Pm ≃10-3 , which explains why it has been overlooked by numerical studies so far.

  12. SATURATED PICRIC ACID PREVENTS AUTOPHAGIA

    Directory of Open Access Journals (Sweden)

    V Rahimi-Movaghar

    2008-08-01

    Full Text Available "nThe dysesthesia and paresthesia that occurs in laboratory rats after spinal cord injury (SCI results in autophagia. This self-destructive behavior interferes with functional assessments in designed studies and jeopardizes the health of the injured rat. In this study, we evaluated role of saturated picric acid in the prevention of autophagia and self-mutilation. All rats were anesthetized with an intraperitoneal injection of a mixture of ketamine (100 mg/kg and xylazine (10 mg/kg for the SCI procedures. In the first 39 rats, no solution applied to the hind limbs, but in the next 26 cases, we smeared the saturated picric acid on the tail, lower extremities, pelvic, and abdomen of the rats immediately after SCI. In the rats without picric acid, 23 rats died following autophagia, but in the 26 rats with picric acid, there was no autophagia (P < 0.001. Picric acid side effects in skin and gastrointestinal signs such as irritation, redness and diarrhea were not seen in any rat. Saturated picric acid is a topical solution that if used appropriately and carefully, might be safe and effectively prevents autophagia and self-mutilation. When the solution is applied to the lower abdomen and limbs, we presume that its bitterness effectively prevents the rat from licking and biting the limb.

  13. Lipid chain saturation and the cholesterol in the phospholipid membrane affect the spectroscopic properties of lipophilic dye nile red

    Science.gov (United States)

    Halder, Animesh; Saha, Baishakhi; Maity, Pabitra; Kumar, Gopinatha Suresh; Sinha, Deepak Kumar; Karmakar, Sanat

    2018-02-01

    We have studied the effect of composition and the phase state of phospholipid membranes on the emission spectrum, anisotropy and lifetime of a lipophilic fluorescence probe nile red. Fluorescence spectrum of nile red in membranes containing cholesterol has also been investigated in order to get insights into the influence of cholesterol on the phospholipid membranes. Maximum emission wavelength (λem) of nile red in the fluid phase of saturated and unsaturated phospholipids was found to differ by 10 nm. The λem was also found to be independent of chain length and charge of the membrane. However, the λem is strongly dependent on the temperature in the gel phase. The λem and rotational diffusion rate decrease, whereas the anisotropy and lifetime increase markedly with increasing cholesterol concentration for saturated phosoholipids, such as, dimyristoyl phosphatidylcholine (DMPC) in the liquid ordered phase. However, these spectroscopic properties do not alter significantly in case of unsaturated phospholipids, such as, dioleoyl phosphatidylcholine (DOPC) in liquid disordered phase. Interestingly, red edge excitation shift (REES) in the presence of lipid-cholesterol membranes is the direct consequences of change in rotational diffusion due to motional restriction of lipids in the presence of cholesterol. This study provides correlations between the membrane compositions and fluorescence spectral features which can be utilized in a wide range of biophysical fields as well the cell biology.

  14. Promoter analysis by saturation mutagenesis

    Directory of Open Access Journals (Sweden)

    Baliga Nitin

    2001-01-01

    Full Text Available Gene expression and regulation are mediated by DNA sequences, in most instances, directly upstream to the coding sequences by recruiting transcription factors, regulators, and a RNA polymerase in a spatially defined fashion. Few nucleotides within a promoter make contact with the bound proteins. The minimal set of nucleotides that can recruit a protein factor is called a cis-acting element. This article addresses a powerful mutagenesis strategy that can be employed to define cis-acting elements at a molecular level. Technical details including primer design, saturation mutagenesis, construction of promoter libraries, phenotypic analysis, data analysis, and interpretation are discussed.

  15. Semiconductor saturable absorbers for ultrafast terahertz signals

    OpenAIRE

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum states, due to conduction band onparabolicity and scattering into satellite valleys in strong THz fields. Saturable absorber parameters, such as linear and nonsaturable transmission, and saturation fluen...

  16. Semiconductor saturable absorbers for ultrafast terahertz signals

    OpenAIRE

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductorsGaAs,GaP, and Ge in the terahertz (THz) frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum states, due to conduction band nonparabolicity and scattering into satellite valleys in strong THz fields. Saturable absorber parameters, such as linear and nonsaturable transmission, and saturation flue...

  17. Mode of interaction of ganglioside Langmuir monolayer originated from echinoderms: three binary systems of ganglioside/DPPC, ganglioside/DMPE, and ganglioside/cholesterol.

    Science.gov (United States)

    Hoda, Kazuki; Ikeda, Yuriko; Kawasaki, Hideya; Yamada, Koji; Higuchi, Ryuichi; Shibata, Osamu

    2006-09-01

    The surface pressure (pi)-area (A), the surface potential (DeltaV)-A, and the dipole moment (mu( perpendicular))-A isotherms were obtained for monolayers made from a ganglioside originated from echinoderms [Diadema setosum ganglioside (DSG-1)], dipalmitoylphosphatidylcholine (DPPC), dimyristoylphosphatidylethanolamine (DMPE), cholesterol (Ch), and their combinations. Monolayers spread on several different substrates were investigated at the air/water interface by the Wilhelmy method, ionizing electrode method, fluorescence microscopy (FM) and atomic force microscopy (AFM). Surface potentials (DeltaV) of pure components were analyzed using the three-layer model proposed by Demchak and Fort [R.J. Demchak, T. Fort, J. Colloid Interface Sci. 46 (1974) 191-202]. The new finding was that DSG-1 was stable and showed a liquid-expanded film and that its monolayer behavior of DeltaV was sensitive for the change of the NaCl concentration in the subphase. Moreover, the miscibility of DSG-1 and three major lipids in the two-component monolayers was examined by plotting the variation of the molecular area and the surface potential as a function of the DSG-1 molar fraction (X(DSG-1)), using the additivity rule. From the A-X(DSG-1) and DeltaV(m)-X(DSG-1) plots, partial molecular surface area (PMA) and apparent partial molecular surface potential (APSP) were determined at the discrete surface pressure. The PMA and APSP with the mole fraction were extensively discussed for the miscible system. The miscibility was also investigated from the two-dimensional phase diagrams. Furthermore, a regular surface mixture, for which the Joos equation was used for the analysis of the collapse pressure of two-component monolayers, allowed calculation of the interaction parameter (xi) and the interaction energy (-Deltavarepsilon) between them. The observations using fluorescence microscopy and AFM image also provide us the miscibility in the monolayer state.

  18. The use of saturation in qualitative research.

    Science.gov (United States)

    Walker, Janiece L

    2012-01-01

    Understanding qualitative research is an important component of cardiovascular nurses' practice and allows them to understand the experiences, stories, and perceptions of patients with cardiovascular conditions. In understanding qualitative research methods, it is essential that the cardiovascular nurse understands the process of saturation within qualitative methods. Saturation is a tool used for ensuring that adequate and quality data are collected to support the study. Saturation is frequently reported in qualitative research and may be the gold standard. However, the use of saturation within methods has varied. Hence, the purpose of this column is to provide insight for the cardiovascular nurse regarding the use of saturation by reviewing the recommendations for which qualitative research methods it is appropriate to use and how to know when saturation is achieved. In understanding saturation, the cardiovascular nurse can be a better consumer of qualitative research.

  19. Structure and dynamics of H{sub 2}O vis-á-vis phenylalanine recognition at a DPPC lipid membrane via interfacial H-bond types: Insights from polarized FT-IRRAS and ADMP simulations

    Energy Technology Data Exchange (ETDEWEB)

    Sarangi, Nirod Kumar; Ramesh, Nivarthi; Patnaik, Archita [Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India)

    2015-01-14

    Preferential and enantioselective interactions of L-/D-Phenylalanine (L-Phe and D-Phe) and butoxycarbonyl-protected L-/D-Phenylalanine (LPA and DPA) as guest with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (L-DPPC) as host were tapped by using real time Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS). Polarization-modulated FT-IRRAS of DPPC monolayers above the phenylalanine modified subphases depicted fine structure/conformation differences under considerations of controlled 2D surface pressure. Selective molecular recognition of D-enantiomer over L-enantiomer driven by the DPPC head group via H-bonding and electrostatic interactions was evident spectroscopically. Accordingly, binding constants (K) of 145, 346, 28, and 56 M{sup −1} for LPA, DPA, L-Phe, and D-Phe, respectively, were estimated. The real time FT-IRRAS water bands were strictly conformation sensitive. The effect of micro-solvation on the structure and stability of the 1:1 diastereomeric L-lipid⋯, LPA/DPA and L-lipid⋯, (L/D)-Phe adducts was investigated with the aid of Atom-centered Density Matrix Propagation (ADMP), a first principle quantum mechanical molecular dynamics approach. The phosphodiester fragment was the primary site of hydration where specific solvent interactions were simulated through single- and triple- “water-phosphate” interactions, as water cluster’s “tetrahedral dice” to a “trimeric motif” transformation as a partial de-clusterization was evident. Under all the hydration patterns considered in both static and dynamic descriptions of density functional theory, L-lipid/D-amino acid enantiomer adducts continued to be stable structures while in dynamic systems, water rearranged without getting “squeezed-out” in the process of recognition. In spite of the challenging computational realm of this multiscale problem, the ADMP simulated molecular interactions complying with polarized vibrational spectroscopy unraveled a novel route to chiral

  20. Power flow control using distributed saturable reactors

    Science.gov (United States)

    Dimitrovski, Aleksandar D.

    2016-02-13

    A magnetic amplifier includes a saturable core having a plurality of legs. Control windings wound around separate legs are spaced apart from each other and connected in series in an anti-symmetric relation. The control windings are configured in such a way that a biasing magnetic flux arising from a control current flowing through one of the plurality of control windings is substantially equal to the biasing magnetic flux flowing into a second of the plurality of control windings. The flow of the control current through each of the plurality of control windings changes the reactance of the saturable core reactor by driving those portions of the saturable core that convey the biasing magnetic flux in the saturable core into saturation. The phasing of the control winding limits a voltage induced in the plurality of control windings caused by a magnetic flux passing around a portion of the saturable core.

  1. Using X-ray computed tomography to evaluate the initial saturation resulting from different saturation procedures

    DEFF Research Database (Denmark)

    Christensen, Britt Stenhøj Baun; Wildenschild, D; Jensen, K.H.

    2006-01-01

    for saturation. Evaluation of the different enhanced saturation techniques was done with Xray computed tomography (CT) and gravimetrically. The use of CT scanning makes it possible to observe the spatial distribution of wetting and non-wetting phases in the porous medium in a non-destructive way. In this case...... with pressurized nitrogen between each saturation and allowed to saturate for the same length of time for all the different procedures. Both gravimetric measurements and CT attenuation levels showed that venting the sample with carbon dioxide prior to saturation clearly improved initial saturation whereas the use...

  2. Synthesis and characterization of saturated polyester and ...

    Indian Academy of Sciences (India)

    and nanocomposites derived from glycolyzed PET waste with varied compositions. SUNAIN KATOCH. ∗ ... Water vapour transmission (WVT) was determined for saturated polyester nanocomposite sheets according to ... ing the synthesis of saturated polyester (from GPET waste). This has been done for the estimation of the ...

  3. Ultrafast THz Saturable Absorption in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate THz saturable absorption in n-doped semiconductors GaAs, GaP, and Ge in a nonlinear THz time-domain spectroscopy experiment. Saturable absorption is caused by sample conductivity modulation due to electron heating and satellite valley scattering in the field of a strong THz pulse....

  4. Fault tolerant control of systems with saturations

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2013-01-01

    This paper presents framework for fault tolerant controllers (FTC) that includes input saturation. The controller architecture known from FTC is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization is extended to handle input saturation. Applying this controller architecture in connec...

  5. Semiconductor saturable absorbers for ultrafast terahertz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum...

  6. Determination of saturation functions and wettability for chalk based on measured fluid saturations

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, D.; Bech, N.; Moeller Nielsen, C.

    1998-08-01

    The end effect of displacement experiments on low permeable porous media is used for determination of relative permeability functions and capillary pressure functions. Saturation functions for a drainage process are determined from a primary drainage experiment. A reversal of the flooding direction creates an intrinsic imbibition process in the sample, which enables determination if imbibition saturation functions. The saturation functions are determined by a parameter estimation technique. Scanning effects are modelled by the method of Killough. Saturation profiles are determined by NMR. (au)

  7. High-pressure infrared spectroscopy of ether- and ester-linked phosphatidylcholine aqueous dispersions.

    Science.gov (United States)

    Siminovitch, D J; Wong, P T; Mantsch, H H

    1987-01-01

    Infrared spectra of aqueous dispersions of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and its ether-linked analogue, 1,2-dihexadecyl-sn-glycero-3-phosphocholine (DHPC), were measured in a diamond anvil cell at 28 degrees C as a function of pressure up to 20 kbar. Although these two lipids differ only in the linkages to the saturated hydrocarbon chains, significant differences were observed in their barotropic behavior. Most notable were the magnitudes of the pressure-induced correlation field splittings of the methylene scissoring and rocking modes, and the relative intensities of the corresponding component bands. In the case of the scissoring mode, not only can the correlation field component band be resolved at a lower pressure in DHPC (1.2 kbar, as compared with 2.2 kbar in DPPC), but the initial magnitude of the correlation field splitting in DHPC, particularly less than 9 kbar, is significantly greater than that observed in DPPC. These differences are attributed to the presence of an interdigitated lamellar gel phase in DHPC. At all pressures where the correlation field component band delta'CH2 can be resolved, the relative peak height/intensity ratio R = I delta'/I delta is greater in DPPC than in DHPC, suggesting that this parameter may be useful as a test of interdigitation. PMID:3567314

  8. Combinatorics of saturated secondary structures of RNA.

    Science.gov (United States)

    Clote, P

    2006-11-01

    Following Zuker (1986), a saturated secondary structure for a given RNA sequence is a secondary structure such that no base pair can be added without violating the definition of secondary structure, e.g., without introducing a pseudoknot. In the Nussinov-Jacobson energy model (Nussinov and Jacobson, 1980), where the energy of a secondary structure is -1 times the number of base pairs, saturated secondary structures are local minima in the energy landscape, hence form kinetic traps during the folding process. Here we present recurrence relations and closed form asymptotic limits for combinatorial problems related to the number of saturated secondary structures. In addition, Python source code to compute the number of saturated secondary structures having k base pairs can be found at the web servers link of bioinformatics.bc.edu/clotelab/.

  9. Saturated fat, carbohydrate, and cardiovascular disease

    National Research Council Canada - National Science Library

    Siri-Tarino, Patty W; Sun, Qi; Hu, Frank B; Krauss, Ronald M

    2010-01-01

    A focus of dietary recommendations for cardiovascular disease (CVD) prevention and treatment has been a reduction in saturated fat intake, primarily as a means of lowering LDL-cholesterol concentrations...

  10. Saturated thickness, High Plains aquifer, 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents the saturated thickness of the High Plains aquifer of the United States, 2009, in feet. The High Plains aquifer underlies...

  11. Semiconductor saturable absorbers for ultrafast THz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths.......We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths....

  12. SATURATED ZONE IN-SITU TESTING

    Energy Technology Data Exchange (ETDEWEB)

    P.W. REIMUS

    2004-11-08

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain, Nevada. The test interpretations provide estimates of flow and transport parameters used in the development of parameter distributions for total system performance assessment (TSPA) calculations. These parameter distributions are documented in ''Site-Scale Saturated Zone Flow Model (BSC 2004 [DIRS 170037]), Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]), Saturated Zone Colloid Transport (BSC 2004 [DIRS 170006]), and ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, this scientific analysis contributes the following to the assessment of the capability of the SZ to serve as part of a natural barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvial Testing Complex (ATC) located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass

  13. Saturated fats and cardiovascular disease risk: A review

    OpenAIRE

    Ishi Khosla; Gayatri C Khosla1

    2017-01-01

    Saturated fats have been in the line of fire for more than three decades. The major mistake in understanding fats was to equate all saturated fatty acids as one. The oversimplification of the relationship of saturated fats with cardiovascular disease (CVD) led to unwarranted removal of some valuable fats from our diets. Recently, the relationship of dietary saturated fats and that of individual saturated fatty acids (SFAs) to CVD risk has been reevaluated. All saturated fats are not equal and...

  14. Current and Noise Saturation in Graphene Superlattice

    Science.gov (United States)

    Yang, Wei; Lu, Xiaobo; Berthou, Simon; Wilmart, Quentin; Boukhicha, Mohamed; Voisin, Christophe; Zhang, Guangyu; Placais, Bernard

    One of the merits of graphene is that the Fermi level can be easily tuned by electrical gating, which render charge carriers n type or p type, or even insulating around the Dirac point (DP). By aligning graphene on top of Boron Nitride (BN), the presence of graphene superlattice makes transport properties even more versatile owning to the emergence of secondary Dirac points (SDPs). Here we present a study of high electric field performance of graphene superlattice obtained from epitaxial approach. By using microwave cavity, noise produced from graphene by joule heating is recorded up to 5GHz. Current and noise saturation are observed and investigated. Depending on Fermi energy, saturation can be attributed to intrinsic optical or remote surface polar phonon scattering at a doping far away from DP, while no saturation are found around DP. Moreover, noise saturation is identified around Fermi energy between DP and SDP, which can be attributed to the influence of van Hove singularity arising from the superlattice. Lastly, saturation due to the bias induced shift of DP, or so called Dirac fermion pinch-off, is well observed by local top gate technique. EU Graphene flagship project (Contract No. 604391).

  15. Lipid order, saturation and surface property relationships: a study of human meibum saturation.

    Science.gov (United States)

    Mudgil, Poonam; Borchman, Douglas; Yappert, Marta C; Duran, Diana; Cox, Gregory W; Smith, Ryan J; Bhola, Rahul; Dennis, Gary R; Whitehall, John S

    2013-11-01

    Tear film stability decreases with age however the cause(s) of the instability are speculative. Perhaps the more saturated meibum from infants may contribute to tear film stability. The meibum lipid phase transition temperature and lipid hydrocarbon chain order at physiological temperature (33 °C) decrease with increasing age. It is reasonable that stronger lipid-lipid interactions could stabilize the tear film since these interactions must be broken for tear break up to occur. In this study, meibum from a pool of adult donors was saturated catalytically. The influence of saturation on meibum hydrocarbon chain order was determined by infrared spectroscopy. Meibum is in an anhydrous state in the meibomian glands and on the surface of the eyelid. The influence of saturation on the surface properties of meibum was determined using Langmuir trough technology. Saturation of native human meibum did not change the minimum or maximum values of hydrocarbon chain order so at temperatures far above or below the phase transition of human meibum, saturation does not play a role in ordering or disordering the lipid hydrocarbon chains. Saturation did increase the phase transition temperature in human meibum by over 20 °C, a relatively high amount. Surface pressure-area studies showing the late take off and higher maximum surface pressure of saturated meibum compared to native meibum suggest that the saturated meibum film is quite molecularly ordered (stiff molecular arrangement) and elastic (molecules are able to rearrange during compression and expansion) compared with native meibum films which are more fluid agreeing with the infrared spectroscopic results of this study. In saturated meibum, the formation of compacted ordered islands of lipids above the surfactant layer would be expected to decrease the rate of evaporation compared to fluid and more loosely packed native meibum. Higher surface pressure observed with films of saturated meibum compared to native meibum

  16. Soil Structure and Saturated Hydraulic Conductivity

    Science.gov (United States)

    Houskova, B.; Nagy, V.

    The role of soil structure on saturated hydraulic conductivity changes is studied in plough layers of texturally different soils. Three localities in western part of Slovakia in Zitny ostrov (Corn Island) were under investigation: locality Kalinkovo with light Calcaric Fluvisol (FAO 1970), Macov with medium heavy Calcari-mollic Fluvisol and Jurova with heavy Calcari-mollic Fluvisol. Soil structure was determined in dry as well as wet state and in size of macro and micro aggregates. Saturated hydraulic conductivity was measured by the help of double ring method. During the period of ring filling the soil surface was protected against aggregates damage by falling water drops. Spatial and temporal variability of studied parameters was evaluated. Cultivated crops were ensilage maize at medium heavy and heavy soil and colza at light soil. Textural composition of soil and actual water content at the beginning of measurement are one of major factor affecting aggregate stability and consequently also saturated hydraulic conductivity.

  17. Perturbative Saturation and the Soft Pomeron

    CERN Document Server

    Kovner, A; Kovner, Alex; Wiedemann, Urs Achim

    2002-01-01

    We show that perturbation theory provides two distinct mechanisms for the power like growth of hadronic cross sections at high energy. One, the leading BFKL effect is due to the growth of the parton density, and is characterized by the leading BFKL exponent. The other mechanism is due to the infrared diffusion, or the long range nature of the Coulomb field of perturbatively massless gluons. When perturbative saturation effects are taken into account, the first mechanism is rendered ineffective but the second one persists. We suggest that these two distinct mechanisms are responsible for the appearance of two pomerons. The density growth effects are responsible for the hard pomeron and manifest themselves in small systems (e.g. gamma^* or small size fluctuations in the proton wave function) where saturation effects are not important. The soft pomeron is the manifestation of the exponential growth of the black saturated regions which appear in typical hadronic systems. We point out that the nonlinear generaliza...

  18. Interger multiplication with overflow detection or saturation

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, M.J.; Balzola, P.I.; Akkas, A.; Brocato, R.W.

    2000-01-11

    High-speed multiplication is frequently used in general-purpose and application-specific computer systems. These systems often support integer multiplication, where two n-bit integers are multiplied to produce a 2n-bit product. To prevent growth in word length, processors typically return the n least significant bits of the product and a flag that indicates whether or not overflow has occurred. Alternatively, some processors saturate results that overflow to the most positive or most negative representable number. This paper presents efficient methods for performing unsigned or two's complement integer multiplication with overflow detection or saturation. These methods have significantly less area and delay than conventional methods for integer multiplication with overflow detection and saturation.

  19. The Danish tax on saturated fat

    DEFF Research Database (Denmark)

    Vallgårda, Signild; Holm, Lotte; Jensen, Jørgen Dejgård

    2015-01-01

    BACKGROUND/OBJECTIVES: Health promoters have repeatedly proposed using economic policy tools, taxes and subsidies, as a means of changing consumer behaviour. As the first country in the world, Denmark introduced a tax on saturated fat in 2011. It was repealed in 2012. In this paper, we present...... on saturated fat had been suggested by two expert committees and was introduced with a majority in parliament, as a part of a larger economic reform package. Many actors, including representatives from the food industry and nutrition researchers, opposed the tax both before and after its introduction, claiming......, research was published showing that consumption of saturated fat had declined in Denmark. CONCLUSIONS: The analysis indicates that the Danish tax on fat was introduced mainly to increase public revenue. As the tax had no strong proponents and many influential adversaries, it was repealed. New research...

  20. Tracking Controller for Intrinsic Output Saturated Systems in Presence of Amplitude and Rate Input Saturations

    DEFF Research Database (Denmark)

    Chater, E.; Giri, F.; Guerrero, Josep M.

    2014-01-01

    We consider the problem of controlling plants that are subject to multiple saturation constraints. Especially, we are interested in linear systems whose input is subject to amplitude and rate constraints of saturation type. Furthermore, the considered systems output is also subject to an intrinsi...

  1. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriette; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michael A.; Spronk, Peter E.

    2012-01-01

    Objective:  The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design:  Prospective observational controlled study. Setting:  Nonacademic university-affiliated

  2. Saturated poroelastic actuators generated by topology optimization

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    2011-01-01

    In this paper the fluid-structure interaction problem of a saturated porous media is considered. The pressure coupling properties of porous saturated materials change with the microstructure and this is utilized in the design of an actuator using a topology optimized porous material. By maximizing...... the coupling of internal fluid pressure and elastic shear stresses a slab of the optimized porous material deflects/deforms when a pressure is imposed and an actuator is created. Several phenomenologically based constraints are imposed in order to get a stable force transmitting actuator....

  3. On the saturation of astrophysical dynamos

    DEFF Research Database (Denmark)

    Dorch, Bertil; Archontis, Vasilis

    2004-01-01

    In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo's mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate in the li......In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo's mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate...

  4. Site-Scale Saturated Zone Flow Model

    Energy Technology Data Exchange (ETDEWEB)

    G. Zyvoloski

    2003-12-17

    The purpose of this model report is to document the components of the site-scale saturated-zone flow model at Yucca Mountain, Nevada, in accordance with administrative procedure (AP)-SIII.lOQ, ''Models''. This report provides validation and confidence in the flow model that was developed for site recommendation (SR) and will be used to provide flow fields in support of the Total Systems Performance Assessment (TSPA) for the License Application. The output from this report provides the flow model used in the ''Site-Scale Saturated Zone Transport'', MDL-NBS-HS-000010 Rev 01 (BSC 2003 [162419]). The Site-Scale Saturated Zone Transport model then provides output to the SZ Transport Abstraction Model (BSC 2003 [164870]). In particular, the output from the SZ site-scale flow model is used to simulate the groundwater flow pathways and radionuclide transport to the accessible environment for use in the TSPA calculations. Since the development and calibration of the saturated-zone flow model, more data have been gathered for use in model validation and confidence building, including new water-level data from Nye County wells, single- and multiple-well hydraulic testing data, and new hydrochemistry data. In addition, a new hydrogeologic framework model (HFM), which incorporates Nye County wells lithology, also provides geologic data for corroboration and confidence in the flow model. The intended use of this work is to provide a flow model that generates flow fields to simulate radionuclide transport in saturated porous rock and alluvium under natural or forced gradient flow conditions. The flow model simulations are completed using the three-dimensional (3-D), finite-element, flow, heat, and transport computer code, FEHM Version (V) 2.20 (software tracking number (STN): 10086-2.20-00; LANL 2003 [161725]). Concurrently, process-level transport model and methodology for calculating radionuclide transport in the saturated zone at Yucca

  5. Fullerene Transport in Saturated Porous Media

    Science.gov (United States)

    We investigated the effects of background solution chemistry and residence time within the soil column on the transport of aqu/C60 through saturated ultrapure quartz sand columns. Aqu/C60 breakthrough curves were obtained under different pore water velocities, solution pHs, and i...

  6. Oxygenation of saturated and unsaturated hydrocarbons with ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 118; Issue 5. Oxygenation of saturated and unsaturated hydrocarbons with sodium periodate catalyzed by manganese(III) tetra-arylporphyrins, to study the axial ligation of imidazole. Reza Tayebee. Volume 118 Issue 5 September 2006 pp 429-433 ...

  7. Nasal pulse oximetry overestimates oxygen saturation

    DEFF Research Database (Denmark)

    Rosenberg, J; Pedersen, M H

    1990-01-01

    Ten surgical patients were monitored with nasal and finger pulse oximetry (Nellcor N-200) for five study periods with alternating mouth and nasal breathing and switching of cables and sensors. Nasal pulse oximetry was found to overestimate arterial oxygen saturation by 4.7 (SD 1.4%) (bias...

  8. Determination of saturated and unsaturated hydraulic conductivity ...

    African Journals Online (AJOL)

    The estimation of hydraulic conductivity indicates how fluids flow through a substance and thus determine the water balance in the soil profile. In determining the saturated and unsaturated hydraulic conductivity of soil, five plots of 5.0 x 4.0 m were prepared with a PVC access tube installed in each plot. The plots were ...

  9. Understanding 'saturation' of radar signals over forests.

    Science.gov (United States)

    Joshi, Neha; Mitchard, Edward T A; Brolly, Matthew; Schumacher, Johannes; Fernández-Landa, Alfredo; Johannsen, Vivian Kvist; Marchamalo, Miguel; Fensholt, Rasmus

    2017-06-14

    There is an urgent need to quantify anthropogenic influence on forest carbon stocks. Using satellite-based radar imagery for such purposes has been challenged by the apparent loss of signal sensitivity to changes in forest aboveground volume (AGV) above a certain 'saturation' point. The causes of saturation are debated and often inadequately addressed, posing a major limitation to mapping AGV with the latest radar satellites. Using ground- and lidar-measurements across La Rioja province (Spain) and Denmark, we investigate how various properties of forest structure (average stem height, size and number density; proportion of canopy and understory cover) simultaneously influence radar backscatter. It is found that increases in backscatter due to changes in some properties (e.g. increasing stem sizes) are often compensated by equal magnitude decreases caused by other properties (e.g. decreasing stem numbers and increasing heights), contributing to the apparent saturation of the AGV-backscatter trend. Thus, knowledge of the impact of management practices and disturbances on forest structure may allow the use of radar imagery for forest biomass estimates beyond commonly reported saturation points.

  10. Wave propagation in thermoelastic saturated porous medium

    Indian Academy of Sciences (India)

    Biot 's theory for wave propagation in saturated porous solid is modified to study the propagation of thermoelastic waves in poroelastic medium. Propagation of plane harmonic waves is considered in isotropic poroelastic medium. Relations are derived among the wave-induced temperature in the medium and the ...

  11. Spontaneous emission from saturated parametric amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Ott, Johan Raunkjær; Steffensen, Henrik

    2009-01-01

    Noise performance of parametric amplifiers is typically calculated assuming un-depleted operation. However, in many applications especially when applied as regenerative amplifiers in systems based on phase shift keyed modulation schemes, this assumption is not valid. Here we show the impact...... on accumulated spontaneous emission for a parametric amplifier operated in saturation....

  12. Elevated transferrin saturation and risk of diabetes

    DEFF Research Database (Denmark)

    Ellervik, Christina; Mandrup-Poulsen, Thomas; Andersen, Henrik Ullits

    2011-01-01

    OBJECTIVE We tested the hypothesis that elevated transferrin saturation is associated with an increased risk of any form of diabetes, as well as type 1 or type 2 diabetes separately. RESEARCH DESIGN AND METHODS We used two general population studies, The Copenhagen City Heart Study (CCHS, N = 9...

  13. Saturated fat, carbohydrates and cardiovascular disease

    NARCIS (Netherlands)

    Kuipers, R. S.; de Graaf, D. J.; Luxwolda, M. F.; Muskiet, M. H. A.; Dijck-Brouwer, D. A. J.; Muskiet, F. A. J.

    The dietary intake of saturated fatty acids (SAFA) is associated with a modest increase in serum total cholesterol, but not with cardiovascular disease (CVD). Replacing dietary SAFA with carbohydrates (CHO), notably those with a high glycaemic index, is associated with an increase in CVD risk in

  14. Two-beam interaction in saturable media

    DEFF Research Database (Denmark)

    Schjødt-Eriksen, Jens; Schmidt, Michel R.; Juul Rasmussen, Jens

    1998-01-01

    The dynamics of two coupled soliton solutions of the nonlinear Schrodinger equation with a saturable nonlinearity is investigated It is shown by means of a variational method and by direct numerical calculations that two well-separated solitons can orbit around each other, if their initial velocity...

  15. Synthesis and characterization of saturated polyester and ...

    Indian Academy of Sciences (India)

    Saturated polyester resin, derived from the glycolysis of polyethyleneterephthalate (PET) was examined as an effective way for PET recycling. The glycolyzed PET (GPET) was reacted with the mixture of phthalic anhydride and ethylene glycol (EG) with varied compositions and their reaction kinetic were studied. During ...

  16. Multi-spectral imaging of oxygen saturation

    Science.gov (United States)

    Savelieva, Tatiana A.; Stratonnikov, Aleksander A.; Loschenov, Victor B.

    2008-06-01

    The system of multi-spectral imaging of oxygen saturation is an instrument that can record both spectral and spatial information about a sample. In this project, the spectral imaging technique is used for monitoring of oxygen saturation of hemoglobin in human tissues. This system can be used for monitoring spatial distribution of oxygen saturation in photodynamic therapy, surgery or sports medicine. Diffuse reflectance spectroscopy in the visible range is an effective and extensively used technique for the non-invasive study and characterization of various biological tissues. In this article, a short review of modeling techniques being currently in use for diffuse reflection from semi-infinite turbid media is presented. A simple and practical model for use with a real-time imaging system is proposed. This model is based on linear approximation of the dependence of the diffuse reflectance coefficient on relation between absorbance and reduced scattering coefficient. This dependence was obtained with the Monte Carlo simulation of photon propagation in turbid media. Spectra of the oxygenated and deoxygenated forms of hemoglobin differ mostly in the red area (520 - 600 nm) and have several characteristic points there. Thus four band-pass filters were used for multi-spectral imaging. After having measured the reflectance, the data obtained are used for fitting the concentration of oxygenated and free hemoglobin, and hemoglobin oxygen saturation.

  17. Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene

    Energy Technology Data Exchange (ETDEWEB)

    Hader, J.; Moloney, J. V. [Nonlinear Control Strategies, Inc., 3542 N. Geronimo Ave., Tucson, Arizona 85705 (United States); College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Yang, H.-J.; Scheller, M. [College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Koch, S. W. [Department of Physics and Materials Sciences Center, Philipps Universität Marburg, Renthof 5, 35032 Marburg (Germany)

    2016-02-07

    Fully microscopic many-body calculations are used to study the influence of strong sub-picosecond pulses on the carrier distributions and corresponding optical response in saturable absorbers used for mode-locking—semiconductor (quantum well) saturable absorber mirrors (SESAMs) and single layer graphene based saturable absorber mirrors (GSAMs). Unlike in GSAMs, the saturation fluence and recovery time in SESAMs show a strong spectral dependence. While the saturation fluence in the SESAM is minimal at the excitonic bandgap, the optimal recovery time and least pulse distortion due to group delay dispersion are found for excitation higher in the first subband. For excitation near the SESAM bandgap, the saturation fluence is about one tenth of that in the GSAM. At energies above the bandgap, the fluences in both systems become similar. A strong dependence of the saturation fluence on the pulse width in both systems is caused by carrier relaxation during the pulse. The recovery time in graphene is found to be about two to four times faster than that in the SESAMs. The occurrence of negative differential transmission in graphene is shown to be caused by dopant related carriers. In SESAMs, a negative differential transmission is found when exciting below the excitonic resonance where excitation induced dephasing leads to an enhancement of the absorption. Comparisons of the simulation data to the experiment show a very good quantitative agreement.

  18. Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene

    Science.gov (United States)

    Hader, J.; Yang, H.-J.; Scheller, M.; Moloney, J. V.; Koch, S. W.

    2016-02-01

    Fully microscopic many-body calculations are used to study the influence of strong sub-picosecond pulses on the carrier distributions and corresponding optical response in saturable absorbers used for mode-locking—semiconductor (quantum well) saturable absorber mirrors (SESAMs) and single layer graphene based saturable absorber mirrors (GSAMs). Unlike in GSAMs, the saturation fluence and recovery time in SESAMs show a strong spectral dependence. While the saturation fluence in the SESAM is minimal at the excitonic bandgap, the optimal recovery time and least pulse distortion due to group delay dispersion are found for excitation higher in the first subband. For excitation near the SESAM bandgap, the saturation fluence is about one tenth of that in the GSAM. At energies above the bandgap, the fluences in both systems become similar. A strong dependence of the saturation fluence on the pulse width in both systems is caused by carrier relaxation during the pulse. The recovery time in graphene is found to be about two to four times faster than that in the SESAMs. The occurrence of negative differential transmission in graphene is shown to be caused by dopant related carriers. In SESAMs, a negative differential transmission is found when exciting below the excitonic resonance where excitation induced dephasing leads to an enhancement of the absorption. Comparisons of the simulation data to the experiment show a very good quantitative agreement.

  19. Refined OPLS all-atom force field for saturated phosphatidylcholine bilayers at full hydration.

    Science.gov (United States)

    Maciejewski, Arkadiusz; Pasenkiewicz-Gierula, Marta; Cramariuc, Oana; Vattulainen, Ilpo; Rog, Tomasz

    2014-05-01

    We report parametrization of dipalmitoyl-phosphatidylcholine (DPPC) in the framework of the Optimized Parameters for Liquid Simulations all-atom (OPLS-AA) force field. We chose DPPC as it is one of the most studied phospholipid species and thus has plenty of experimental data necessary for model validation, and it is also one of the highly important and abundant lipid types, e.g., in lung surfactant. Overall, PCs have not been previously parametrized in the OPLS-AA force field; thus, there is a need to derive its bonding and nonbonding parameters for both the polar and nonpolar parts of the molecule. In the present study, we determined the parameters for torsion angles in the phosphatidylcholine and glycerol moieties and in the acyl chains, as well the partial atomic charges. In these calculations, we used three methods: (1) Hartree-Fock (HF), (2) second order Møller-Plesset perturbation theory (MP2), and (3) density functional theory (DFT). We also tested the effect of the polar environment by using the polarizable continuum model (PCM), and for acyl chains the van der Waals parameters were also adjusted. In effect, six parameter sets were generated and tested on a DPPC bilayer. Out of these six sets, only one was found to be able to satisfactorily reproduce experimental data for the lipid bilayer. The successful DPPC model was obtained from MP2 calculations in an implicit polar environment (PCM).

  20. Replacing foods high in saturated fat by low-saturated fat alternatives: a computer simulation of the potential effects on reduction of saturated fat consumption

    NARCIS (Netherlands)

    Schickenberg, B.; Assema, P.; Brug, J.; Verkaik-Kloosterman, J.; Ocke, M.C.; Vries, de N.

    2009-01-01

    10 en%) increased from 23.3 % to 86.0 %. We conclude that the replacement of relatively few important high-saturated fat products by available lower-saturated fat alternatives can significantly reduce saturated fat intake and increase the proportion of individuals complying with recommended intake

  1. Saturated Zone In-Situ Testing

    Energy Technology Data Exchange (ETDEWEB)

    P. W. Reimus; M. J. Umari

    2003-12-23

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that have been conducted to test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain. The test interpretations provide estimates of flow and transport parameters that are used in the development of parameter distributions for Total System Performance Assessment (TSPA) calculations. These parameter distributions are documented in the revisions to the SZ flow model report (BSC 2003 [ 162649]), the SZ transport model report (BSC 2003 [ 162419]), the SZ colloid transport report (BSC 2003 [162729]), and the SZ transport model abstraction report (BSC 2003 [1648701]). Specifically, this scientific analysis report provides the following information that contributes to the assessment of the capability of the SZ to serve as a barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvium Testing Complex (ATC), which is located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, and

  2. Comparison of pulseoximetry oxygen saturation and arterial oxygen saturation in open heart intensive care unit

    Directory of Open Access Journals (Sweden)

    Alireza Mahoori

    2013-08-01

    Full Text Available Background: Pulseoximetry is widely used in the critical care setting, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO2 (puls-eoximetry oxygen saturation in intensive care unit after cardiac surgery. Our objective was to compare pulseoximetry with arterial oxygen saturation (SaO2 during clinical routine in such patients, and to examine the effect of mild acidosis on this relationship.Methods: In an observational prospective study 80 patients were evaluated in intensive care unit after cardiac surgery. SPO2 was recorded and compared with SaO2 obtained by blood gas analysis. One or serial arterial blood gas analyses (ABGs were performed via a radial artery line while a reliable pulseoximeter signal was present. One hundred thirty seven samples were collected and for each blood gas analyses, SaO2 and SPO2 we recorded.Results: O2 saturation as a marker of peripheral perfusion was measured by Pulseoxim-etry (SPO2. The mean difference between arterial oxygen saturation and pulseoximetry oxygen saturation was 0.12%±1.6%. A total of 137 paired readings demonstrated good correlation (r=0.754; P<0.0001 between changes in SPO2 and those in SaO2 in samples with normal hemoglobin. Also in forty seven samples with mild acidosis, paired readings demonstrated good correlation (r=0.799; P<0.0001 and the mean difference between SaO2 and SPO2 was 0.05%±1.5%.Conclusion: Data showed that in patients with stable hemodynamic and good signal quality, changes in pulseoximetry oxygen saturation reliably predict equivalent changes in arterial oxygen saturation. Mild acidosis doesn’t alter the relation between SPO2 and SaO2 to any clinically important extent. In conclusion, the pulse oximeter is useful to monitor oxygen saturation in patients with stable hemodynamic.

  3. [Monitoring of jugular venous oxygen saturation].

    Science.gov (United States)

    Nakamura, Shunsuke

    2011-04-01

    The continuous monitoring of jugular venous oxygen saturation(SjO2) has become a practical method for monitoring global cerebral oxygenation and metabolism. SjO2 reflects the balance between the cerebral blood flow and the cerebral metabolic rate for oxygen (CMRO2), if arterial oxyhemoglobin saturation, hemoglobin concentration remain constant. Normal SjO2 values range between 55% and 75%. Low SjO2 indicates cerebral hypoperfusion or ischemia. Conversely, an increased SjO2 indicates either cerebral hyperemia or a disorder that decreases CMRO2. In minimizing secondary brain damage following resuscitation from cardiopulmonary arrest, SjO2 monitoring is thus considered to be an integral part of multimodality monitoring and can provide important information for the management of patients in neurointensive care.

  4. The danish tax on saturated fat

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Smed, Sinne

    Denmark introduced a new tax on saturated fat in food products with effect from October 2011. The objective of this paper is to make an effect assessment of this tax for some of the product categories most significantly affected by the new tax, namely fats such as butter, butter-blends, margarine...... on saturated fat in food products has had some effects on the market for the considered products, in that the level of consumption of fats dropped by 10 – 20%. Furthermore, the analysis points at shifts in demand from high-price supermarkets towards low-price discount stores – a shift that seems to have been...... – and broaden – the analysis at a later stage, when data are available for a longer period after the introduction of the fat tax....

  5. Nonlinear saturation of Weibel-type instabilities

    Science.gov (United States)

    Srinivasan, Bhuvana; Cagas, Petr; Hakim, Ammar

    2017-10-01

    Weibel-type instabilities, which grow in plasmas with anisotropic velocity distribution, have been studied for many years and drawn recent interest due to their broad applicability spanning from laboratory laser plasmas to origins of intergalactic magnetic fields in astrophysical plasmas. Magnetic particle trapping has been considered as the main mechanism of the nonlinear saturation of these instabilities. However, novel continuum kinetic and two-fluid five moment simulations show that there are additional effects - the transverse flow introduced by the magnetic field creates a secondary electrostatic two-stream instability which alters the saturation and is responsible for a quasi-periodic behavior in the nonlinear phase. This research was supported by the Air Force Office of Scientific Research under Grant Number FA9550-15-1-0193.

  6. WAter Saturation Shift Referencing (WASSR) for chemical exchange saturation transfer experiments

    Science.gov (United States)

    Kim, Mina; Gillen, Joseph; Landman, Bennett. A.; Zhou, Jinyuan; van Zijl, Peter C.M.

    2010-01-01

    Chemical exchange saturation transfer (CEST) is a contrast mechanism exploiting exchange-based magnetization transfer (MT) between solute and water protons. CEST effects compete with direct water saturation and conventional MT processes and generally can only be quantified through an asymmetry analysis of the water saturation spectrum (Z-spectrum) with respect to the water frequency, a process that is exquisitely sensitive to magnetic field inhomogeneities. Here, it is shown that direct water saturation imaging allows measurement of the absolute water frequency in each voxel, allowing proper centering of Z-spectra on a voxel-by-voxel basis independent of spatial B0 field variations. Optimal acquisition parameters for this “water saturation shift referencing” or “WASSR” approach were estimated using Monte Carlo simulations and later confirmed experimentally. The optimal ratio of the WASSR sweep width to the linewidth of the direct saturation curve was found to be 3.3–4.0, requiring a sampling of 16–32 points. The frequency error was smaller than 1 Hz at signal to noise ratios of 40 or higher. The WASSR method was applied to study glycogen, where the chemical shift difference between the hydroxyl (OH) protons and bulk water protons at 3T is so small (0.75–1.25 ppm) that the CEST spectrum is inconclusive without proper referencing. PMID:19358232

  7. Water saturation shift referencing (WASSR) for chemical exchange saturation transfer (CEST) experiments.

    Science.gov (United States)

    Kim, Mina; Gillen, Joseph; Landman, Bennett A; Zhou, Jinyuan; van Zijl, Peter C M

    2009-06-01

    Chemical exchange saturation transfer (CEST) is a contrast mechanism that exploits exchange-based magnetization transfer (MT) between solute and water protons. CEST effects compete with direct water saturation and conventional MT processes, and generally can only be quantified through an asymmetry analysis of the water saturation spectrum (Z-spectrum) with respect to the water frequency, a process that is exquisitely sensitive to magnetic field inhomogeneities. Here it is shown that direct water saturation imaging allows measurement of the absolute water frequency in each voxel, allowing proper centering of Z-spectra on a voxel-by-voxel basis independently of spatial B(0) field variations. Optimal acquisition parameters for this "water saturation shift referencing" (WASSR) approach were estimated using Monte Carlo simulations and later confirmed experimentally. The optimal ratio of the WASSR sweep width to the linewidth of the direct saturation curve was found to be 3.3-4.0, requiring a sampling of 16-32 points. The frequency error was smaller than 1 Hz at signal-to-noise ratios of 40 or higher. The WASSR method was applied to study glycogen, where the chemical shift difference between the hydroxyl (OH) protons and bulk water protons at 3T is so small (0.75-1.25 ppm) that the CEST spectrum is inconclusive without proper referencing.

  8. Gluon saturation beyond (naive) leading logs

    Energy Technology Data Exchange (ETDEWEB)

    Beuf, Guillaume

    2014-12-15

    An improved version of the Balitsky–Kovchegov equation is presented, with a consistent treatment of kinematics. That improvement allows to resum the most severe of the large higher order corrections which plague the conventional versions of high-energy evolution equations, with approximate kinematics. This result represents a further step towards having high-energy QCD scattering processes under control beyond strict Leading Logarithmic accuracy and with gluon saturation effects.

  9. 2D Saturable Absorbers for Fibre Lasers

    Directory of Open Access Journals (Sweden)

    Robert I. Woodward

    2015-11-01

    Full Text Available Two-dimensional (2D nanomaterials are an emergent and promising platform for future photonic and optoelectronic applications. Here, we review recent progress demonstrating the application of 2D nanomaterials as versatile, wideband saturable absorbers for Q-switching and mode-locking fibre lasers. We focus specifically on the family of few-layer transition metal dichalcogenides, including MoS2, MoSe2 and WS2.

  10. Stabilization of Neutral Systems with Saturating Actuators

    Directory of Open Access Journals (Sweden)

    F. El Haoussi

    2012-01-01

    to determine stabilizing state-feedback controllers with large domain of attraction, expressed as linear matrix inequalities, readily implementable using available numerical tools and with tuning parameters that make possible to select the most adequate solution. These conditions are derived by using a Lyapunov-Krasovskii functional on the vertices of the polytopic description of the actuator saturations. Numerical examples demonstrate the effectiveness of the proposed technique.

  11. Saturated Dispersive Extinction Theory of Red Shift

    Science.gov (United States)

    Wang, Ling Jun

    2012-03-01

    The Dispersive Extinction Theory (DET) proposed by WangfootnotetextWang, Ling Jun, Physics Essays, 18, No. 2, (2005). offers an alternative to the Big Bang. According to DET, the cosmic red shift is caused by the dispersive extinction of the star light during the propagation from the stars to the earth, instead of being caused by the Doppler shift due to the expansion of the universe.footnotetextHubble, E., Astrophys. J. 64, 321 (1926).^,footnotetextHubble, E., The Realm of the Nebulae, (Yale University Press, New Haven, 1936). DET allows an infinite, stable, non expanding universe, and is immune of the fundamental problems inherent to the Big Bang such as the horizon problem, the extreme violation of the conservation of mass, energy and charge, and the geocentric nature which violates the principle of relativity.footnotetextWang, Ling Jun, Physics Essays, 20, No. 2, (2007). The scenario dealt with in Reference (1) is a one in which the extinction by the space medium is not saturated. This work deals with a different scenario when the extinction is saturated. The saturated extinction causes limited energy loss, and the star light can travel a much greater distance than in the unsaturated scenario.

  12. Optimal oxygen saturation in premature infants

    Directory of Open Access Journals (Sweden)

    Meayoung Chang

    2011-09-01

    Full Text Available There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation (SpO2 is 90 to 93% with an intermittent review of the correlation between SpO2 and the partial pressure of arterial oxygen tension (PaO2. Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

  13. A study of the antibacterial activity of L-phenylalanine and L-tyrosine esters in relation to their CMCs and their interactions with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC as model membrane.

    Science.gov (United States)

    Joondan, Nausheen; Jhaumeer-Laulloo, Sabina; Caumul, Prakashanand

    2014-01-01

    Cationic amino acid-based surfactants are known to interact with the lipid bilayer of cell membranes resulting in depolarization, lysis and cell death through a disruption of the membrane topology. A range of cationic surfactant analogues derived from L-Phenylalanine (C1-C20) and L-Tyrosine (C8-C14) esters have been synthesized and screened for their antibacterial activity. The esters were more active against gram positive than gram negative bacteria. The activity increased with increasing chain length, exhibiting a cut-off effect at C12 for gram positive and C8/C10 for gram negative bacteria. The cut-off effect for gram negative bacteria was observed at a lower alkyl chain length. The CMC was correlated with the MIC, inferring that micellar activity contribute to the cut-off effect in antibacterial activity. The interaction of the cationic surfactants with the phospholipid vesicles (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC) in the presence of 1-anilino-8-naphthalene sulfonate (ANS) and 1,6-diphenyl-1,3,5-hexatriene (DPH) as fluorescence probes showed that an increase in ionic interaction causes an increase in antibacterial activity. Increase in hydrophobic interaction increases the antibacterial activity only to a certain chain length, attributing to the cut-off effect. Therefore, both electrostatic and hydrophobic interactions, involving the polar and nonpolar moieties are of paramount importance for the bactericidal properties. Copyright © 2014 Elsevier GmbH. All rights reserved.

  14. PLD-grown thin film saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Tellkamp, Friedjof

    2012-11-01

    The subject of this thesis is the preparation and characterization of thin films made of oxidic dielectrics which may find their application as saturable absorber in passively Q-switched lasers. The solely process applied for fabrication of the thin films was the pulsed laser deposition (PLD) which stands out against other processes by its flexibility considering the composition of the systems to be investigated. Within the scope of this thesis the applied saturable absorbers can be divided into two fundamentally different kinds of functional principles: On the one hand, saturable absorption can be achieved by ions embedded in a host medium. Most commonly applied bulk crystals are certain garnets like YAG (Y{sub 3}Al{sub 5}O{sub 12}) or the spinel forsterite (Mg{sub 2}SiO{sub 4}), in each case with chromium as dopant. Either of these media was investigated in terms of their behavior as PLD-grown saturable absorber. Moreover, experiments with Mg{sub 2}GeO{sub 4}, Ca{sub 2}GeO{sub 4}, Sc{sub 2}O{sub 3}, and further garnets like YSAG or GSGG took place. The absorption coefficients of the grown films of Cr{sup 4+}:YAG were determined by spectroscopic investigations to be one to two orders of magnitude higher compared to commercially available saturable absorbers. For the first time, passive Q-switching of a Nd:YAG laser at 1064 nm with Cr{sup 4+}:YAG thin films could be realized as well as with Cr:Sc{sub 2}O{sub 3} thin films. On the other hand, the desirable effect of saturable absorption can also be generated by quantum well structures. For this purpose, several layer system like YAG/LuAG, Cu{sub 2}O/MgO, and ZnO/corumdum were investigated. It turned out that layer systems with indium oxide (In{sub 2}O{sub 3}) did not only grew in an excellent way but also showed up a behavior regarding their photo luminescence which cannot be explained by classical considerations. The observed luminescence at roughly 3 eV (410 nm) was assumed to be of excitonic nature and its

  15. Trans Fat Now Listed With Saturated Fat and Cholesterol

    Science.gov (United States)

    ... Trans Fat Now Listed With Saturated Fat and Cholesterol Share Tweet Linkedin Pin it More sharing options ... I Do About Saturated Fat, Trans Fat, and Cholesterol? When comparing foods, look at the Nutrition Facts ...

  16. Calcium phosphate saturation in the western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.; Reddy, C.V.G.

    Temperature, inorganic phosphate concentration and pH seem to be the major factors influencing the degree of saturation of calcium phosphate in sea water. Two water regions can be demarcated in the study area based on the saturation patterns...

  17. Nonmonotone Saturation Profiles for Hydrostatic Equilibrium in Homogeneous Porous Media

    NARCIS (Netherlands)

    Hilfer, R.; Doster, F.; Zegeling, P.A.|info:eu-repo/dai/nl/073634433

    2012-01-01

    Nonmonotonic saturation profiles (saturation overshoot) occur as travelling waves in gravity driven fingering. They seem important for preferential flow mechanisms and have found much attention recently. Here, we predict them even for hydrostatic equilibrium when all velocities vanish. We suggest

  18. Heavy Flavor Production in DGLAP improved Saturation Model

    CERN Document Server

    Sapeta, S

    2007-01-01

    The saturation model with DGLAP evolution is shown to give good description of the production of the charm and beauty quarks in deep inelastic scattering. The modifications of saturation properties caused by the presence of heavy quarks are also discussed.

  19. Rigid aleph_epsilon-saturated models of superstable theories

    OpenAIRE

    Shami, Ziv; Shelah, Saharon

    1999-01-01

    In a countable superstable NDOP theory, the existence of a rigid aleph_epsilon-saturated model implies the existence of 2^lambda rigid aleph_epsilon-saturated models of power lambda for every lambda>2^{aleph_0}.

  20. Silica fractal atomic clusters saturated with OH

    CERN Document Server

    Olivi-Tran, N

    2003-01-01

    We constructed regular fractal SiOH atomic clusters which pending bonds are saturated with OH molecules. We calculated the binding energies of these clusters as well as for sp sup 2 hybridization as for sp sup 3 hybridizations. The result are the following: for the two hybridizations, the total binding energies have a linear dependence on the size of the fractal cluster, which comes directly from the scaling law of the fractal characteristic of the building of the cluster. We related by a scaling law, the number of electronic bonds and the total bonding energy.

  1. Chloride diffusion in partially saturated cementitious material

    DEFF Research Database (Denmark)

    Nielsen, Erik Pram; Geiker, Mette Rica

    2003-01-01

    The paper proposes a combined application of composite theory and Powers' model for microstructural development for the estimation of the diffusion coefficient as a function of the moisture content of a defect-free cementitious material. Measurements of chloride diffusion in mortar samples (440 kg....../m(3) rapid-hardening Portland cement, w/c = 0.5, maturity minimum 6 months) stored at 65% and 85% RH, as well as in vacuum-saturated mortar samples, illustrate the applicability of the method. (C) 2003 Elsevier Science Ltd. All rights reserved....

  2. Inheritance of reduced saturated fatty acid content in sunflower oil

    OpenAIRE

    Vick Brady A.; Jan C.C.; Miller Jerry F.

    2002-01-01

    In recent years, consumers have become concerned with reducing the saturated fat content of their diet. Studies have indicated that high levels of saturated fat consumption are correlated with increased risk of coronary heart disease. The total saturated fat content of oil from current sunflower hybrids averages about 130 g kg-1. To identify sunflower germplasm with reduced saturated fatty acid composition, a total of 884 cultivated sunflower accessions from the USDA-ARS North Central Regiona...

  3. Test of Scintillometer Saturation Correction Methods Using Field Experimental Data

    NARCIS (Netherlands)

    Kleissl, J.; Hartogensis, O.K.; Gomez, J.D.

    2010-01-01

    Saturation of large aperture scintillometer (LAS) signals can result in sensible heat flux measurements that are biased low. A field study with LASs of different aperture sizes and path lengths was performed to investigate the onset of, and corrections for, signal saturation. Saturation already

  4. A demonstration experiment for studying the properties of saturated vapor

    Science.gov (United States)

    Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.

    2017-11-01

    The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation vapor, partial pressure, and the dependence of saturated vapor pressure on temperature.

  5. SITE-SCALE SATURATED ZONE TRANSPORT

    Energy Technology Data Exchange (ETDEWEB)

    S. KELLER

    2004-11-03

    This work provides a site-scale transport model for calculating radionuclide transport in the saturated zone (SZ) at Yucca Mountain, for use in the abstractions model in support of ''Total System Performance Assessment for License Application'' (TSPA-LA). The purpose of this model report is to provide documentation for the components of the site-scale SZ transport model in accordance with administrative procedure AP-SIII.10Q, Models. The initial documentation of this model report was conducted under the ''Technical Work Plan For: Saturated Zone Flow and Transport Modeling and Testing'' (BSC 2003 [DIRS 163965]). The model report has been revised in accordance with the ''Technical Work Plan For: Natural System--Saturated Zone Analysis and Model Report Integration'', Section 2.1.1.4 (BSC 2004 [DIRS 171421]) to incorporate Regulatory Integration Team comments. All activities listed in the technical work plan that are appropriate to the transport model are documented in this report and are described in Section 2.1.1.4 (BSC 2004 [DIRS 171421]). This report documents: (1) the advection-dispersion transport model including matrix diffusion (Sections 6.3 and 6.4); (2) a description and validation of the transport model (Sections 6.3 and 7); (3) the numerical methods for simulating radionuclide transport (Section 6.4); (4) the parameters (sorption coefficient, Kd ) and their uncertainty distributions used for modeling radionuclide sorption (Appendices A and C); (5) the parameters used for modeling colloid-facilitated radionuclide transport (Table 4-1, Section 6.4.2.6, and Appendix B); and (6) alternative conceptual models and their dispositions (Section 6.6). The intended use of this model is to simulate transport in saturated fractured porous rock (double porosity) and alluvium. The particle-tracking method of simulating radionuclide transport is incorporated in the finite-volume heat and mass transfer numerical

  6. Energy dependent saturable and reverse saturable absorption in cube-like polyaniline/polymethyl methacrylate film

    Energy Technology Data Exchange (ETDEWEB)

    Thekkayil, Remyamol [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); Philip, Reji [Light and Matter Physics Group, Raman Research Institute, C.V. Raman Avenue, Bangalore 560 080 (India); Gopinath, Pramod [Department of Physics, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); John, Honey, E-mail: honey@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India)

    2014-08-01

    Solid films of cube-like polyaniline synthesized by inverse microemulsion polymerization method have been fabricated in a transparent PMMA host by an in situ free radical polymerization technique, and are characterized by spectroscopic and microscopic techniques. The nonlinear optical properties are studied by open aperture Z-scan technique employing 5 ns (532 nm) and 100 fs (800 nm) laser pulses. At the relatively lower laser pulse energy of 5 μJ, the film shows saturable absorption both in the nanosecond and femtosecond excitation domains. An interesting switchover from saturable absorption to reverse saturable absorption is observed at 532 nm when the energy of the nanosecond laser pulses is increased. The nonlinear absorption coefficient increases with increase in polyaniline concentration, with low optical limiting threshold, as required for a good optical limiter. - Highlights: • Synthesized cube-like polyaniline nanostructures. • Fabricated polyaniline/PMMA nanocomposite films. • At 5 μJ energy, saturable absorption is observed both at ns and fs regime. • Switchover from SA to RSA is observed as energy of laser beam increases. • Film (0.1 wt % polyaniline) shows high β{sub eff} (230 cm GW{sup −1}) and low limiting threshold at 150 μJ.

  7. Femoral venous oxygen saturation and central venous oxygen saturation in critically ill patients.

    Science.gov (United States)

    Zhang, Xiaohong; Wang, Jiandong; Dong, Yun; Chen, Youdai

    2015-08-01

    To investigate the relationship between central venous oxygen saturation (ScvO(2)) and femoral venous oxygen saturation (SfvO(2)) in a large group of critically ill patients. Observational study. A group of unselected critically ill patients with central line placed into superior vena cava were included. A 26-bed intensive care unit in a tertiary referral hospital. None. Venous blood samples of superior vena cava and femoral vein were collected within an interval of 5 to 15 minutes and analyzed with blood gas/electrolyte analyzer immediately. Although SfvO(2) was significantly correlated with ScvO(2) (r = 0.493, P 731 pairs of blood samples collected from 357 patients. The fit line of scatter diagram ScvO(2) vs SfvO(2) had a large intercept (48.68%) and a low slope (0.2978); ScvO(2) was still around 50% while SfvO(2) was nearing 0%. The distribution of blood flow, measured with Doppler ultrasound, had a similar trend in 237 patients and 412 measurements. The ratio of femoral artery flow over common carotid artery flow varied widely (from 0 to 7.13). Blood flow was not distributed in a fixed ratio to the superior vena cava-drained organs and tissues. Central venous oxygen saturation was not representative of the whole systemic circulation in critically ill patients. Central venous oxygen saturation alone might be misleading in goal-directed therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. A sulfide-saturated lunar mantle?

    Science.gov (United States)

    Brenan, James M.; Mungall, James E.

    2017-04-01

    Although much work has been done to understand the controls on the sulfur content at sulfide saturation (SCSS) for terrestrial melt compositions, little information exists to evaluate the SCSS for the high FeO compositions typical of lunar magmas, and at the reduced conditions of the Moon's interior. Experiments were done to measure the SCSS for a model low Ti mare basalt with 20 wt% FeO at 1400oC as a function of fO2 and pressure. Synthetic lunar basalt was encapsulated along with stoichiometric FeS in capsules made from Fe-Ir alloy. The fO2 of the experiment can be estimated by the heterogeneous equilibrium: Femetal + 1 /2 O2 = FeOsilicate Variation in the metal composition, by addition of Ir, serves to change the fO2 of the experiment. Capsule compositions spanning the range Fe25Ir75 to Fe96Ir4 (at%) were synthesized by sintering of pressed powders under reducing conditions. Fe100 capsules were fabricated from pure Fe rod. For a melt with 20 wt% FeO, this range in capsule composition spans the fO2 interval of ˜IW-1 (Fe100, Fe96Ir4) to IW+2.2 (Fe25Ir75). Experiments were done over the pressure interval of 0.1 MPa to 2 GPa. Results for experiments involving Fe100capsules indicate that the SCSS decreases from ˜2000 ppm (0.1 MPa) to 700 ppm (2 GPa). Experiments done thus far at 1 GPa, involving the range of capsule compositions indicated, show a marked decrease in SCSS as the Fe content of the capsule increases (fO2 decreases). Complementary to the decrease in SCSS is a drop in the sulfur content of the coexisting sulfide melt, from ˜50 at% at ΔIW = +2.2 to ˜20 at% at ΔIW-1. In fact, both the composition of the sulfide melt and the SCSS are essentially indistinguishable for Fe96Ir4 and Fe100 compositions. Results thus far indicate that at reduced conditions and high pressure, the SCSS for high FeO lunar compositions is low, and overlaps with Apollo 11 melt inclusion data. Importantly, such low SCSS does not require Fe metal saturation, and suggests that some

  9. From QCD to nuclear matter saturation

    Energy Technology Data Exchange (ETDEWEB)

    Ericson, Magda [Universite de Lyon, Univ. Lyon 1, CNRS/IN2P3, IPN Lyon, F-69622 Villeurbanne Cedex (France)]|[Theory division, CERN, CH-12111 Geneva (Switzerland); Chanfray, Guy [Universite de Lyon, Univ. Lyon 1, CNRS/IN2P3, IPN Lyon, F-69622 Villeurbanne Cedex (France)

    2007-03-15

    We discuss a relativistic chiral theory of nuclear matter with {sigma} and {omega} exchange using a formulation of the {sigma} model in which all the chiral constraints are automatically fulfilled. We establish a relation between the nuclear response to the scalar field and the QCD one which includes the nucleonic parts. It allows a comparison between nuclear and QCD information. Going beyond the mean field approach we introduce the effects of the pion loops supplemented by the short-range interaction. The corresponding Landau-Migdal parameters are taken from spin-isospin physics results. The parameters linked to the scalar meson exchange are extracted from lattice QCD results. These inputs lead to a reasonable description of the saturation properties, illustrating the link between QCD and nuclear physics. We also derive from the corresponding equation of state the density dependence of the quark condensate and of the QCD susceptibilities. (authors)

  10. The Danish tax on saturated fat

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Smed, Sinne

    2013-01-01

    Denmark introduced a new tax on saturated fat in food products with effect from October 2011. The objective of this paper is to make an effect assessment of this tax for some of the product categories most significantly affected by the new tax, namely fats such as butter, butter-blends, margarine...... fat in food products has had some effects on the market for the considered products, in that the level of consumption of fats dropped by 10 – 20%. Furthermore, the analysis points at shifts in demand from high-price supermarkets towards low-price discount stores – at least for some types of oils...... and fats, a shift that seems to have been utilized by discount chains to raise the prices of butter and margarine by more than the pure tax increase. Due to the relatively short data period with the tax being active, interpretation of these findings from a long-run perspective should be done...

  11. Saturation of Van Allen's belts; Saturation des ceintures de Van Allen

    Energy Technology Data Exchange (ETDEWEB)

    Le Bel, E.; Simonet, F. [CEA Bruyeres-le-Chatel, 91 (France)

    2002-12-01

    The maximum number of electrons that can be trapped in van Allen's belts has been evaluated at CEA-DAM more precisely than that commonly used in the space community. The modelization that we have developed allows to understand the disagreement (factor 50) observed between the measured and predicted electrons flux by US satellites and theory. This saturation level allows sizing-up of the protection on a satellite in case of energetic events. (authors)

  12. Reaching saturation in patterned source vertical organic field effect transistors

    Science.gov (United States)

    Greenman, Michael; Sheleg, Gil; Keum, Chang-min; Zucker, Jonathan; Lussem, Bjorn; Tessler, Nir

    2017-05-01

    Like most of the vertical transistors, the Patterned Source Vertical Organic Field Effect Transistor (PS-VOFET) does not exhibit saturation in the output characteristics. The importance of achieving a good saturation is demonstrated in a vertical organic light emitting transistor; however, this is critical for any application requiring the transistor to act as a current source. Thereafter, a 2D simulation tool was used to explain the physical mechanisms that prevent saturation as well as to suggest ways to overcome them. We found that by isolating the source facet from the drain-source electric field, the PS-VOFET architecture exhibits saturation. The process used for fabricating such saturation-enhancing structure is then described. The new device demonstrated close to an ideal saturation with only 1% change in the drain-source current over a 10 V change in the drain-source voltage.

  13. Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy.

    Science.gov (United States)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra Ma; Hendrikse, Jeroen; Groenendaal, Floris; van Bel, Frank; Benders, Manon Jnl; Petersen, Esben T

    2017-03-01

    Although near-infrared spectroscopy is increasingly being used to monitor cerebral oxygenation in neonates, it has a limited penetration depth. The T2-prepared Blood Imaging of Oxygen Saturation (T2-BIOS) magnetic resonance sequence provides an oxygen saturation estimate on a voxel-by-voxel basis, without needing a respiratory calibration experiment. In 15 neonates, oxygen saturation measured by T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy were compared. In addition, these measures were compared to cerebral blood flow and venous oxygen saturation in the sagittal sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy ( R2 = 0.64, p infrared spectroscopy oxygen saturation, and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus ( R2 = 0.71, 0.50, 0.65; p infrared spectroscopy and T2-prepared blood imaging of oxygen saturation, confirming the validity of using of these techniques for determining cerebral oxygenation.

  14. Trehalose-induced destabilization of interdigitated gel phase in dihexadecylphosphatidylcholine.

    Science.gov (United States)

    Takahashi, H; Ohmae, H; Hatta, I

    1997-01-01

    Trehalose is believed to have the ability to protect some organisms against low temperatures. To clarify the cryoprotective mechanism of trehalose, the structure and the phase behavior of fully hydrated dihexadecylphosphatidylcholine (DHPC) membranes in the presence of various concentrations of trehalose were studied by means of differential scanning calorimetry (DSC), static x-ray diffraction, and simultaneous x-ray diffraction and DSC measurements. The temperature of the interdigitated gel (Lbeta(i))-to-ripple (Pbeta') phase transition of DHPC decreases with a rise in trehalose concentration up to approximately 1.0 M. Above a trehalose concentration of approximately 1.0 M, no Lbeta(i) phase is observed. In this connection, the electron density profile calculated from the lamellar diffraction data in the presence of 1.6 M trehalose indicates that DHPC forms noninterdigitated bilayers below the P beta' phase. It was concluded that trehalose destabilizes the Lbeta(i) phase of DHPC bilayers. This suggests that trehalose reduces the area at the interface between the lipid and water. The relation between this effect of trehalose and a low temperature tolerance was discussed from the viewpoint of cold-induced denaturation of proteins. PMID:9414217

  15. Quantitative 1D saturation profiles on chalk by NMR

    DEFF Research Database (Denmark)

    Olsen, Dan; Topp, Simon; Stensgaard, Anders

    1996-01-01

    Quantitative one-dimensional saturation profiles showing the distribution of water and oil in chalk core samples are calculated from NMR measurements utilizing a 1D CSI spectroscopy pulse sequence. Saturation profiles may be acquired under conditions of fluid flow through the sample. Results reveal...... that strong saturation gradients exist in chalk core samples after core floods, due to capillary effects. The method is useful in analysis of corefloods, e.g., for determination of capillary pressure functions...

  16. Saturated fat -a never ending story?

    Science.gov (United States)

    Svendsen, Karianne; Arnesen, Erik; Retterstøl, Kjetil

    2017-01-01

    Science has no clear message regarding health effects of saturated fats, it seems. Different RCTs, prospective cohort studies and meta-analysis have led to contrasting conclusions. The aim of the present commentary is to discuss some possible reasons for an apparently never-ending fat controversy. They are of a purely scientific nature, which is important to recognize, but unfortunately hard to overcome. First is the placebo problem. In pharmaceutical science, evidence-based medicine is often synonymous with data on verified medical events from long-lasting double-blind randomized placebo controlled trials. In nutritional science the lack of double-blind design and lack of placebo food generate less conclusive data than those achieved in pharmaceutical science. Some scientists may apply the same type of scientific criteria used to evaluate the effects of drugs for foods. This leaves an impression of insufficient data since in this respect the fundamental criteria for evidence based medicine are not present. The next scientific problem is the energy balance equation. In contrast to pharmaceuticals, nutrients contain energy. An increased intake of one nutrient will lead to a decreased intake of another. The effect of change in only one nutrient is then difficult to isolate. Lastly, in nutritional science, generalizability is difficult compared to pharmaceutical science. Food culture interferes with lifestyle and food habits change over time. In conclusion, all available knowledge, from molecular experiments to population studies, must be taken in to account, to convert scientific data into dietary recommendations.

  17. Assaying Carcinoembryonic Antigens by Normalized Saturation Magnetization

    Science.gov (United States)

    Huang, Kai-Wen; Chieh, Jen-Jie; Shi, Jin-Cheng; Chiang, Ming-Hsien

    2015-07-01

    Biofunctionalized magnetic nanoparticles (BMNs) that provide unique advantages have been extensively used to develop immunoassay methods. However, these developed magnetic methods have been used only for specific immunoassays and not in studies of magnetic characteristics of materials. In this study, a common vibration sample magnetometer (VSM) was used for the measurement of the hysteresis loop for different carcinoembryonic antigens (CEA) concentrations ( Φ CEA) based on the synthesized BMNs with anti-CEA coating. Additionally, magnetic parameters such as magnetization ( M), remanent magnetization ( M R), saturation magnetization ( M S), and normalized parameters (Δ M R/ M R and Δ M S/ M S) were studied. Here, Δ M R and Δ M s were defined as the difference between any ΦCEA and zero Φ CEA. The parameters M, Δ M R, and Δ M S increased with Φ CEA, and Δ M S showed the largest increase. Magnetic clusters produced by the conjugation of the BMNs to CEAs showed a Δ M S greater than that of BMNs. Furthermore, the relationship between Δ M S/ M S and Φ CEA could be described by a characteristic logistic function, which was appropriate for assaying the amount of CEAs. This analytic Δ M S/ M S and the BMNs used in general magnetic immunoassays can be used for upgrading the functions of the VSM and for studying the magnetic characteristics of materials.

  18. Sensorial saturation and neonatal pain: a review.

    Science.gov (United States)

    Locatelli, Chiara; Bellieni, Carlo Valerio

    2017-08-23

    Sensorial saturation (SS) is an analgesic approach to babies' pain that includes three types of stimulations: oral sugar, massage and caregivers' voice. The aim of this review is to assess its efficacy. We performed an analysis of scientific literature from 2001 to 2017, retrieving those clinical trials where SS had been compared with other analgesic treatments during procedural pain in babies. We retrieved 14 studies. Pain sources were heel-prick in nine, eye examination and intramuscular shots in two each, and endotracheal aspiration in one. SS was the most effective treatment in all cases, except in endotracheal suctioning. No drawbacks were reported in any study using SS. SS is a safe and effective approach to neonatal pain due to heel-prick, more effective than oral sucrose or glucose in both term and preterm babies; it seems also effective in other types of acute procedural pain like eye examination or intramuscular injections, but more studies are needed to confirm these preliminary data. More studies are also needed to test SS efficacy for other procedures, and for older infants.

  19. SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION

    Energy Technology Data Exchange (ETDEWEB)

    B.W. ARNOLD

    2004-10-27

    The purpose of the saturated zone (SZ) flow and transport model abstraction task is to provide radionuclide-transport simulation results for use in the total system performance assessment (TSPA) for license application (LA) calculations. This task includes assessment of uncertainty in parameters that pertain to both groundwater flow and radionuclide transport in the models used for this purpose. This model report documents the following: (1) The SZ transport abstraction model, which consists of a set of radionuclide breakthrough curves at the accessible environment for use in the TSPA-LA simulations of radionuclide releases into the biosphere. These radionuclide breakthrough curves contain information on radionuclide-transport times through the SZ. (2) The SZ one-dimensional (I-D) transport model, which is incorporated in the TSPA-LA model to simulate the transport, decay, and ingrowth of radionuclide decay chains in the SZ. (3) The analysis of uncertainty in groundwater-flow and radionuclide-transport input parameters for the SZ transport abstraction model and the SZ 1-D transport model. (4) The analysis of the background concentration of alpha-emitting species in the groundwater of the SZ.

  20. Interaction forces and membrane charge tunability: Oleic acid containing membranes in different pH conditions.

    Science.gov (United States)

    Kurniawan, James; Suga, Keishi; Kuhl, Tonya L

    2017-02-01

    Oleic acid is known to interact with saturated lipid molecules and increase the fluidity of gel phase lipid membranes. In this work, the thermodynamic properties of mixed monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and oleic acid at the air-water interface were determined using Langmuir isotherms. The isotherm study revealed an attractive interaction between oleic acid and DPPC. The incorporation of oleic acid also monotonically decreased the elastic modulus of the monolayer indicative of higher fluidity with increasing oleic acid content. Using the surface force apparatus, intermembrane force-distance profiles were obtained for substrate supported DPPC membranes containing 30mol% oleic acid at pH5.8 and 7.4. Three different preparation conditions resulted in distinct force profiles. Membranes prepared in pH5.8 subphase had a low number of nanoscopic defects ≤1% and an adhesion magnitude of ~0.6mN/m. A slightly higher defect density of 1-4% was found for membranes prepared in a physiological pH7.4 subphase. The presence of the exposed hydrophobic moieties resulted in a higher adhesion magnitude of 2.9mN/m. Importantly, at pH7.4, some oleic acid deprotonates resulting in a long-range electrostatic repulsion. Even though oleic acid increased the DPPC bilayer fluidity and the number of defects, no membrane restructuring was observed indicating that the system maintained a stable configuration. Copyright © 2016. Published by Elsevier B.V.

  1. Can Polyphosphate Biochemistry Affect Biological Apatite Saturation?

    Science.gov (United States)

    Omelon, S. J.; Matsuura, N.; Gorelikov, I.; Wynnyckyj, C.; Grynpas, M. D.

    2010-12-01

    Phosphorus (P) is an important and limiting element for life. One strategy for storing ortho phosphates (Pi) is polymerization. Polymerized Pi's (polyphosphates: (PO3-)n: polyPs) serve as a Pi bank, as well as a catiion chelator, energy source, & regulator of responses to stresses in the stationary phase of culture growth and development1. PolyP biochemistry has been investigated in yeasts, bacteria & plants2. Bigeochemical cycling of P includes the condensation of Pi into pyro (P2O7-4), & polyPs, & the release of Pi from these compounds by the hydrolytic degradation of Pi from phosphomonoester bonds. Alkaline phosphatase (ALP) is one of the predominate enzymes for regenerating Pi in aquatic systems3, & it cleaves Pi from polyPs. ALP is also the enzyme associated with apatite biomineralization in vertebrates4. PolyP was proposed to be the ALP substrate in bone mineralization5. Where calcium ions are plentiful in many aquatic environments, there is no requirement for aquatic life to generate Ca-stores. However, terrestrial vertebrates benefit from a bioavailable Ca-store such as apatite. The Pi storage strategy of polymerizing PO4-3 into polyPs dovetails well with Ca-banking, as polyPs sequester Ca, forming a neutral calcium polyphosphate (Ca-polyP: (Ca(PO3)2)n) complex. This neutral complex represents a high total [Ca+2] & [PO4-3], without the threat of inadvertent apatite precipitation, as the free [Ca+2] & [PO4-3], and therefore apatite saturation, are zero. Recent identification of polyP in regions of bone resorption & calcifying cartilage5 suggests that vertebrates may use polyP chemistry to bank Ca+2 and PO4-3. In vitro experiments with nanoparticulate Ca-polyP & ALP were undertaken to determine if carbonated apatite could precipitate from 1M Ca-polyP in Pi-free “physiological fluid” (0.1 M NaCl, 2 mM Ca+2, 0.8 mM Mg+2, pH ~8.0 ±0.5, 37 °C), as this is estimated to generate the [Ca+2] & [PO4-3] required to form the apatite content of bone tissue

  2. Prioritized Control Allocation for Quadrotors Subject to Saturation

    NARCIS (Netherlands)

    Smeur, E.J.J.; de Wagter, C.; J.-M. Moschetta G. Hattenberger, H. de Plinval

    2017-01-01

    This paper deals with the problem of actuator saturation for INDI (Incremental Nonlinear Dynamic Inversion) controlled flying vehicles. The primary problem that arises from actuator saturation for quadrotors, is that of arbitrary control objective realization. We have integrated the weighted least

  3. Polar spots and stellar spindown: is dynamo saturation needed?

    NARCIS (Netherlands)

    Solanki, S. K.; Motamen, S.; Keppens, R.

    1997-01-01

    Dynamo saturation is often invoked when calculating the rotational evolution of cool stars. At rapid rotation rates a saturated dynamo reduces the angular momentum carried away by the stellar wind. This, in turn, may explain the high rotation rates present in the distribution of rotation periods in

  4. Polar spots and stellar spindown: Is dynamo saturation needed?

    NARCIS (Netherlands)

    Solanki, S. K.; Motamen, S.; Keppens, R.

    1997-01-01

    Dynamo saturation is often invoked when calculating the rotational evolution of cool stars. At rapid rotation rates a saturated dynamo reduces the angular momentum carried away by the stellar wind. This, in turn, may explain the high rotation rates present in the distribution of rotation periods in

  5. Gain characteristics of a saturated fiber optic parametric amplifier

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Lorenzen, Michael Rodas; Noordegraaf, Danny

    2008-01-01

    In this work we discuss saturation performance of a fiber optic parametric amplifier. A simple numerical model is described and applied to specific cases. A system experiment using a saturated amplifier illustrates a 4 dB improvement in required signal to noise ratio for a fixed bit error ratio....

  6. Renal vein oxygen saturation in renal artery stenosis

    DEFF Research Database (Denmark)

    Nielsen, K; Rehling, M; Henriksen, Jens Henrik Sahl

    1992-01-01

    Renal vein oxygen-saturation was measured in 56 patients with arterial hypertension and unilateral stenosis or occlusion of the renal artery. Oxygen-saturation in blood from the ischaemic kidney (84.4%, range 73-93%) was significantly higher than that from the 'normal' contralateral kidney (81...

  7. Comparison of empirical models and laboratory saturated hydraulic ...

    African Journals Online (AJOL)

    Numerous methods for estimating soil saturated hydraulic conductivity exist, which range from direct measurement in the laboratory to models that use only basic soil properties. A study was conducted to compare laboratory saturated hydraulic conductivity (Ksat) measurement and that estimated from empirical models.

  8. Stability and stabilization of linear systems with saturating actuators

    CERN Document Server

    Tarbouriech, Sophie; Gomes da Silva Jr, João Manoel; Queinnec, Isabelle

    2011-01-01

    Gives the reader an in-depth understanding of the phenomena caused by the more-or-less ubiquitous problem of actuator saturation. Proposes methods and algorithms designed to avoid, manage or overcome the effects of actuator saturation. Uses a state-space approach to ensure local and global stability of the systems considered. Compilation of fifteen years' worth of research results.

  9. Excitable solitons in a semiconductor laser with a saturable absorber

    Science.gov (United States)

    Turconi, Margherita; Prati, Franco; Barland, Stéphane; Tissoni, Giovanna

    2015-11-01

    Self-pulsing cavity solitons may exist in a semiconductor laser with an intracavity saturable absorber. They show locally the passive Q -switching behavior that is typical of lasers with saturable absorbers in the plane-wave approximation. Here we show that excitable cavity solitons are also possible in a suitable parameter range and characterize their excitable dynamics and properties.

  10. Saturated hydraulic conductivity values of some forest soils of ...

    African Journals Online (AJOL)

    A simple falling-head method is presented for the laboratory determination of saturated hydraulic conductivity of some forest soils of Ghana. Using the procedure, it was found that saturated hydraulic conductivity was positively and negatively correlated with sand content and clay content, respectively, both at P = 0.05 level.

  11. Significance of saturation index of certain clay minerals in shallow ...

    Indian Academy of Sciences (India)

    In reality, a number of kinetic reasons exist that may ..... of SI with increase of pH. This increase of pH reduces the availability of H+ for ion exchange. Group B: The SI of Gibbsite ranges from near saturation to saturation. This may be due to the .... tion of ions in solution which emphasizes increased contribution of species with ...

  12. Serum albumin--a non-saturable carrier

    DEFF Research Database (Denmark)

    Brodersen, R; Honoré, B; Larsen, F G

    1984-01-01

    The shape of binding isotherms for sixteen ligands to human serum albumin showed no signs of approaching saturation at high ligand concentrations. It is suggested that ligand binding to serum albumin is essentially different from saturable binding of substrates to enzymes, of oxygen to haemoglobi...

  13. Retinal oxygen saturation in patients with systemic hypoxemia

    DEFF Research Database (Denmark)

    Traustason, Sindri; Jensen, Annette Schophuus; Arvidsson, Henrik Sven

    2011-01-01

    To assess spectrophotometric oximetry across a broad range of arterial saturation levels and to study the effect of chronic systemic hypoxemia on retinal oxygen extraction.......To assess spectrophotometric oximetry across a broad range of arterial saturation levels and to study the effect of chronic systemic hypoxemia on retinal oxygen extraction....

  14. Estimation of Saturation Flow Rates at Signalized Intersections

    Directory of Open Access Journals (Sweden)

    Chang-qiao Shao

    2012-01-01

    Full Text Available The saturation flow rate is a fundamental parameter to measure the intersection capacity and time the traffic signals. However, it is revealed that traditional methods which are mainly developed using the average value of observed queue discharge headways to estimate the saturation headway might lead to underestimate saturation flow rate. The goal of this paper is to study the stochastic nature of queue discharge headways and to develop a more accurate estimate method for saturation headway and saturation flow rate. Based on the surveyed data, the characteristics of queue discharge headways and the estimation method of saturated flow rate are studied. It is found that the average value of queue discharge headways is greater than the median value and that the skewness of the headways is positive. Normal distribution tests were conducted before and after a log transformation of the headways. The goodness-of-fit test showed that for some surveyed sites, the queue discharge headways can be fitted by the normal distribution and for other surveyed sites, the headways can be fitted by lognormal distribution. According to the queue discharge headway characteristics, the median value of queue discharge headways is suggested to estimate the saturation headway and a new method of estimation saturation flow rates is developed.

  15. Design, physicochemical characterization, and optimization of organic solution advanced spray-dried inhalable dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine poly(ethylene glycol) (DPPE-PEG) microparticles and nanoparticles for targeted respiratory nanomedicine delivery as dry powder inhalation aerosols

    Science.gov (United States)

    Meenach, Samantha A; Vogt, Frederick G; Anderson, Kimberly W; Hilt, J Zach; McGarry, Ronald C; Mansour, Heidi M

    2013-01-01

    Novel advanced spray-dried and co-spray-dried inhalable lung surfactant-mimic phospholipid and poly(ethylene glycol) (PEG)ylated lipopolymers as microparticulate/nanoparticulate dry powders of biodegradable biocompatible lipopolymers were rationally formulated via an organic solution advanced spray-drying process in closed mode using various phospholipid formulations and rationally chosen spray-drying pump rates. Ratios of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine PEG (DPPE-PEG) with varying PEG lengths were mixed in a dilute methanol solution. Scanning electron microscopy images showed the smooth, spherical particle morphology of the inhalable particles. The size of the particles was statistically analyzed using the scanning electron micrographs and SigmaScan® software and were determined to be 600 nm to 1.2 μm in diameter, which is optimal for deep-lung alveolar penetration. Differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) were performed to analyze solid-state transitions and long-range molecular order, respectively, and allowed for the confirmation of the presence of phospholipid bilayers in the solid state of the particles. The residual water content of the particles was very low, as quantified analytically via Karl Fischer titration. The composition of the particles was confirmed using attenuated total-reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and confocal Raman microscopy (CRM), and chemical imaging confirmed the chemical homogeneity of the particles. The dry powder aerosol dispersion properties were evaluated using the Next Generation Impactor™ (NGI™) coupled with the HandiHaler® dry powder inhaler device, where the mass median aerodynamic diameter from 2.6 to 4.3 μm with excellent aerosol dispersion performance, as exemplified by high values of emitted dose, fine particle fraction, and respirable fraction. Overall, it was determined that the pump rates defined in the

  16. Dynamics of saturated energy condensation in two-dimensional turbulence.

    Science.gov (United States)

    Chan, Chi-kwan; Mitra, Dhrubaditya; Brandenburg, Axel

    2012-03-01

    In two-dimensional forced Navier-Stokes turbulence, energy cascades to the largest scales in the system to form a pair of coherent vortices known as the Bose condensate. We show, both numerically and analytically, that the energy condensation saturates and the system reaches a statistically stationary state. The time scale of saturation is inversely proportional to the viscosity and the saturation energy level is determined by both the viscosity and the force. We further show that, without sufficient resolution to resolve the small-scale enstrophy spectrum, numerical simulations can give a spurious result for the saturation energy level. We also find that the movement of the condensate is similar to the motion of an inertial particle with an effective drag force. Furthermore, we show that the profile of the saturated coherent vortices can be described by a Gaussian core with exponential wings.

  17. The distribution of saturated clusters in wetted granular materials

    Science.gov (United States)

    Li, Shuoqi; Hanaor, Dorian; Gan, Yixiang

    2017-06-01

    The hydro-mechanical behaviour of partially saturated granular materials is greatly influenced by the spatial and temporal distribution of liquid within the media. The aim of this paper is to characterise the distribution of saturated clusters in granular materials using an optical imaging method under different water drainage conditions. A saturated cluster is formed when a liquid phase fully occupies the pore space between solid grains in a localized region. The samples considered here were prepared by vibrating mono-sized glass beads to form closely packed assemblies in a rectangular container. A range of drainage conditions were applied to the specimen by tilting the container and employing different flow rates, and the liquid pressure was recorded at different positions in the experimental cell. The formation of saturated clusters during the liquid withdrawal processes is governed by three competing mechanisms arising from viscous, capillary, and gravitational forces. When the flow rate is sufficiently large and the gravity component is sufficiently small, the viscous force tends to destabilize the liquid front leading to the formation of narrow fingers of saturated material. As the water channels along these liquid fingers break, saturated clusters are formed inside the specimen. Subsequently, a spatial and temporal distribution of saturated clusters can be observed. We investigated the resulting saturated cluster distribution as a function of flow rate and gravity to achieve a fundamental understanding of the formation and evolution of such clusters in partially saturated granular materials. This study serves as a bridge between pore-scale behavior and the overall hydro-mechanical characteristics in partially saturated soils.

  18. Saturated phosphatidic acids mediate saturated fatty acid–induced vascular calcification and lipotoxicity

    Science.gov (United States)

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Keenan, Audrey L.; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; Ntambi, James M.; Kuro-o, Makoto; Miyazaki, Makoto

    2015-01-01

    Recent evidence indicates that saturated fatty acid–induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic events in the development of vascular calcification. We evaluated whether SMC-specific inhibition of SCD and the resulting SFA accumulation plays a causative role in the pathogenesis of vascular calcification and generated mice with SMC-specific deletion of both Scd1 and Scd2. Mice lacking both SCD1 and SCD2 in SMCs displayed severe vascular calcification with increased ER stress. Moreover, we employed shRNA library screening and radiolabeling approaches, as well as in vitro and in vivo lipidomic analysis, and determined that fully saturated phosphatidic acids such as 1,2-distearoyl-PA (18:0/18:0-PA) mediate SFA-induced lipotoxicity and vascular calcification. Together, these results identify a key lipogenic pathway in SMCs that mediates vascular calcification. PMID:26517697

  19. Saturated phosphatidic acids mediate saturated fatty acid-induced vascular calcification and lipotoxicity.

    Science.gov (United States)

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Keenan, Audrey L; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; Ntambi, James M; Kuro-O, Makoto; Miyazaki, Makoto

    2015-10-26

    Recent evidence indicates that saturated fatty acid-induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic events in the development of vascular calcification. We evaluated whether SMC-specific inhibition of SCD and the resulting SFA accumulation plays a causative role in the pathogenesis of vascular calcification and generated mice with SMC-specific deletion of both Scd1 and Scd2. Mice lacking both SCD1 and SCD2 in SMCs displayed severe vascular calcification with increased ER stress. Moreover, we employed shRNA library screening and radiolabeling approaches, as well as in vitro and in vivo lipidomic analysis, and determined that fully saturated phosphatidic acids such as 1,2-distearoyl-PA (18:0/18:0-PA) mediate SFA-induced lipotoxicity and vascular calcification. Together, these results identify a key lipogenic pathway in SMCs that mediates vascular calcification.

  20. Elastoplastic model for unsaturated, quasi-saturated and fully saturated fine soils

    Directory of Open Access Journals (Sweden)

    Lai Ba Tien

    2016-01-01

    Full Text Available In unsaturated soils, the gaseous phase is commonly assumed to be continuous. This assumption is no more valid at high saturation ratio. In that case, air bubbles and pockets can be trapped in the porous network by the liquid phase and the gas phase becomes discontinuous. This trapped air reduces the apparent compressibility of the pore fluid and affect the mechanical behavior of the soil. Although it is trapped in the pores, its dissolution can take place. Dissolved air can migrate through the pore space, either by following the flow of the fluid or by diffusion. In this context, this paper present a hydro mechanical model that separately considers the kinematics and the mechanical behavior of each fluid species (eg liquid water, dissolved air, gaseous air and the solid matrix. This new model was implemented in a C++ code. Some numerical simulations are performed to demonstrate the ability of this model to reproduce a continuous transition of unsaturated to saturated states.

  1. Changes in air saturation and air water interfacial area during surfactant-enhanced air sparging in saturated sand

    Science.gov (United States)

    Kim, Heonki; Choi, Kyong-Min; Moon, Ji-Won; Annable, Michael D.

    2006-11-01

    Reduction in the surface tension of groundwater, prior to air sparging for removal of volatile organic contaminant from aquifer, can greatly enhance the air content and the extent of influence when air sparging is implemented. However, detailed information on the functional relationship between water saturation, air-water contact area induced by air sparging and the surface tension of water has not been available. In this study, the influence of adding water-soluble anionic surfactant (sodium dodecyl benzene sulfonate) into groundwater before air sparging on the air-water interfacial area and water saturation was investigated using a laboratory-scale sand packed column. It was found that water saturation decreases with decreasing surface tension of water until it reaches a point where this trend is reversed so that water saturation increases with further decrease in the surface tension. The lowest water saturation of 0.58 was achieved at a surface tension of 45.4 dyn/cm, which is considered as the optimum surface tension for maximum de-saturation for the initially water-saturated sand used in this study. The air-water contact area generated in the sand column due to air sparging was measured using a gaseous interfacial tracer, n-decane, and was found to monotonically increase with decreasing water saturation. The results of this study provide useful design information for surfactant-enhanced air sparging removal of volatile contaminants from aquifers.

  2. Saturated fats: a perspective from lactation and milk composition.

    Science.gov (United States)

    German, J Bruce; Dillard, Cora J

    2010-10-01

    For recommendations of specific targets for the absolute amount of saturated fat intake, we need to know what dietary intake is most appropriate? Changing agricultural production and processing to lower the relative quantities of macronutrients requires years to accomplish. Changes can have unintended consequences on diets and the health of subsets of the population. Hence, what are the appropriate absolute amounts of saturated fat in our diets? Is the scientific evidence consistent with an optimal intake of zero? If not, is it also possible that a finite intake of saturated fats is beneficial to overall health, at least to a subset of the population? Conclusive evidence from prospective human trials is not available, hence other sources of information must be considered. One approach is to examine the evolution of lactation, and the composition of milks that developed through millennia of natural selective pressure and natural selection processes. Mammalian milks, including human milk, contain 50% of their total fatty acids as saturated fatty acids. The biochemical formation of a single double bond converting a saturated to a monounsaturated fatty acid is a pathway that exists in all eukaryotic organisms and is active within the mammary gland. In the face of selective pressure, mammary lipid synthesis in all mammals continues to release a significant content of saturated fatty acids into milk. Is it possible that evolution of the mammary gland reveals benefits to saturated fatty acids that current recommendations do not consider?

  3. Elastic velocities of partially gas-saturated unconsolidated sediments

    Science.gov (United States)

    Lee, M.W.

    2004-01-01

    Fluid in sediments significantly affects elastic properties of sediments and gas in the pore space can be identified by a marked reduction of P-wave velocity or a decrease of Poisson's ratio. The elastic properties of gas-saturated sediments can be predicted by the classical Biot-Gassmann theory (BGT). However, parameters for the BGT such as the Biot coefficient or moduli of dry frame of unconsolidated and high porosity sediments are not readily available. Dependence of velocities on differential pressure or porosity for partially gas-saturated sediments is formulated using properties derived from velocities of water-saturated sediments. Laboratory samples for unconsolidated and consolidated sediments and well log data acquired for unconsolidated marine sediments agree well with the predictions. However, because the P-wave velocity depends highly on how the gas is saturated in the pore space such as uniform or patch, the amounts of gas estimated from the P-wave velocity contains high uncertainty. The modeled Vp/Vs ratio of partially gas-saturated sediment using the patch distribution is usually greater than 1.6, whereas the ratio modeled assuming a uniform distribution is about 1.6. Thus, Poisson's ratio or Vp/Vs ratio may be used to differentiate patch from uniform saturation, but differences between various models of patch saturation cannot be easily identified. ?? 2004 Elsevier Ltd. All rights reserved.

  4. Red cell aspartate aminotransferase saturation with oral pyridoxine intake

    Directory of Open Access Journals (Sweden)

    Marilena Oshiro

    Full Text Available CONTEXT AND OBJECTIVE: The coenzyme of aspartate aminotransferase is pyridoxal phosphate, generated from fresh vegetables containing pyridoxine. Vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronie’s syndrome respond to high pyridoxine doses. The objective was to investigate the oral pyridoxine oral dose that would lead to maximized pyridoxal phosphate saturation of red cell aspartate aminotransferase. DESIGN AND SETTING: Controlled trial, in Hematology Division of Instituto Adolfo Lutz. METHODS: Red cell aspartate aminotransferase activity was assayed (before and after in normal volunteers who were given oral pyridoxine for 15-18 days (30 mg, 100 mg and 200 mg daily. In vitro study of blood from seven normal volunteers was also performed, with before and after assaying of aspartate aminotransferase activity. RESULTS: The in vivo study showed increasing aspartate aminotransferase saturation with increasing pyridoxine doses. 83% saturation was reached with 30 mg daily, 88% with 100 mg, and 93% with 200 mg after 20 days of oral supplementation. The in vitro study did not reach 100% saturation. CONCLUSIONS: Neither in vivo nor in vitro study demonstrated thorough aspartate aminotransferase saturation with its coenzyme pyridoxal phosphate in red cells, from increasing pyridoxine supplementation. However, the 200-mg dose could be employed safely in vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronie’s syndrome treatment. Although maximum saturation in circulating red cells is not achieved, erythroblasts and other nucleated and cytoplasmic organelles containing cells certainly will reach thorough saturation, which possibly explains the results obtained in these diseases.

  5. Saturation Detection-Based Blocking Scheme for Transformer Differential Protection

    Directory of Open Access Journals (Sweden)

    Byung Eun Lee

    2014-07-01

    Full Text Available This paper describes a current differential relay for transformer protection that operates in conjunction with a core saturation detection-based blocking algorithm. The differential current for the magnetic inrush or over-excitation has a point of inflection at the start and end of each saturation period of the transformer core. At these instants, discontinuities arise in the first-difference function of the differential current. The second- and third-difference functions convert the points of inflection into pulses, the magnitudes of which are large enough to detect core saturation. The blocking signal is activated if the third-difference of the differential current is larger than the threshold and is maintained for one cycle. In addition, a method to discriminate between transformer saturation and current transformer (CT saturation is included. The performance of the proposed blocking scheme was compared with that of a conventional harmonic blocking method. The test results indicate that the proposed scheme successfully discriminates internal faults even with CT saturation from the magnetic inrush, over-excitation, and external faults with CT saturation, and can significantly reduce the operating time delay of the relay.

  6. On the propagation of a coupled saturation and pressure front

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, D. W.

    2010-12-01

    Using an asymptotic technique, valid for a medium with smoothly varying heterogeneity, I derive an expression for the velocity of a propagating, coupled saturation and pressure front. Due to the nonlinearity of the governing equations, the velocity of the propagating front depends upon the magnitude of the saturation and pressure changes across the front in addition to the properties of the medium. Thus, the expression must be evaluated in conjunction with numerical reservoir simulation. The propagation of the two-phase front is governed by the background saturation distribution, the saturation-dependent component of the fluid mobility, the porosity, the permeability, the capillary pressure function, the medium compressibility, and the ratio of the slopes of the relative permeability curves. Numerical simulation of water injection into a porous layer saturated with a nonaqueous phase liquid indicates that two modes of propagation are important. The fastest mode of propagation is a pressure-dominated disturbance that travels through the saturated layer. This is followed, much later, by a coupled mode with a large saturation change. These two modes are also observed in a simulation using a heterogeneous porous layer. A comparison between the propagation times estimated from the results of the numerical simulation and predictions from the asymptotic expression indicates overall agreement.

  7. Hydrate morphology: Physical properties of sands with patchy hydrate saturation

    Science.gov (United States)

    Dai, S.; Santamarina, J.C.; Waite, William F.; Kneafsey, T.J.

    2012-01-01

    The physical properties of gas hydrate-bearing sediments depend on the volume fraction and spatial distribution of the hydrate phase. The host sediment grain size and the state of effective stress determine the hydrate morphology in sediments; this information can be used to significantly constrain estimates of the physical properties of hydrate-bearing sediments, including the coarse-grained sands subjected to high effective stress that are of interest as potential energy resources. Reported data and physical analyses suggest hydrate-bearing sands contain a heterogeneous, patchy hydrate distribution, whereby zones with 100% pore-space hydrate saturation are embedded in hydrate-free sand. Accounting for patchy rather than homogeneous hydrate distribution yields more tightly constrained estimates of physical properties in hydrate-bearing sands and captures observed physical-property dependencies on hydrate saturation. For example, numerical modeling results of sands with patchy saturation agree with experimental observation, showing a transition in stiffness starting near the series bound at low hydrate saturations but moving toward the parallel bound at high hydrate saturations. The hydrate-patch size itself impacts the physical properties of hydrate-bearing sediments; for example, at constant hydrate saturation, we find that conductivity (electrical, hydraulic and thermal) increases as the number of hydrate-saturated patches increases. This increase reflects the larger number of conductive flow paths that exist in specimens with many small hydrate-saturated patches in comparison to specimens in which a few large hydrate saturated patches can block flow over a significant cross-section of the specimen.

  8. Dynamics of Saturated Energy Condensation in Two-Dimensional Turbulence

    CERN Document Server

    Chan, Chi-kwan; Brandenburg, Axel

    2011-01-01

    We derive and numerically confirm that the saturation of energy condensation in two-dimensional turbulence is governed by the balance between forcing and small-scale dissipation. The time scale of saturation is inversely proportional to the viscosity but the saturation energy level is determined by both viscosity and the forcing scale. It is shown that, because the energy dissipation is proportional to the enstrophy, which itself is a conserved quantity in the ideal case, it is necessary to resolve the enstrophy spectrum to achieve numerical consistency. We also find that the movement of the condensate vortices can be described as Brownian motion of an inertial particle.

  9. Femtosecond Yb:YAG laser using semiconductor saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Hoenninger, C.; Zhang, G.; Keller, U. [Ultrafast Laser Physics, Institute of Quantum Electronics, Swiss Federal Institute of Technology, ETH Hoenggerberg--HPT, CH-8093 Zuerich (Switzerland); Giesen, A. [Institut fuer Strahlwerkzeuge, Universitaet Stuttgart, Pfaffenwaldring 43, D-70569 Stuttgart (Germany)

    1995-12-01

    We demonstrate a passively mode-locked femtosecond Yb:YAG laser using different semiconductor saturable absorber devices, a high-finesse and a low-finesse antiresonant Fabry{endash}Perot saturable absorber. We achieved pulses as short as 540 fs with dispersion compensation and 1.7-ps pulses without dispersion compensation. We also mode locked the laser at either 1.03 or 1.05 {mu}m by adjusting the band gap and antiresonance wavelength design of the antiresonant Fabry{endash}Perot saturable absorber. {copyright} {ital 1995 Optical Society of America.}

  10. Investigation of saturation effects in ceramic phosphors for laser lighting

    DEFF Research Database (Denmark)

    Krasnoshchoka, Anastasiia; Thorseth, Anders; Dam-Hansen, Carsten

    2017-01-01

    We report observation of saturation effects in a Ce:LuAG and Eu-doped nitride ceramic phosphor for conversion of blue laser light for white light generation. The luminous flux from the phosphors material increases linearly with the input power until saturation effects limit the conversion....... It is shown, that the temperature of the phosphor layer influences the saturation power level and the conversion efficiency. It is also shown that the correlated color temperature (CCT), phosphor conversion efficiency and color rendering index (CRI) are dependent both on incident power and spot size diameter...

  11. Using historical biogeography to test for community saturation.

    Science.gov (United States)

    Pinto-Sánchez, Nelsy Rocío; Crawford, Andrew J; Wiens, John J

    2014-09-01

    Saturation is the idea that a community is effectively filled with species, such that no more can be added without extinctions. This concept has important implications for many areas of ecology, such as species richness, community assembly, invasive species and climate change. Here, we illustrate how biogeography can be used to test for community saturation, when combined with data on local species richness, phylogeny and climate. We focus on a clade of frogs (Terrarana) and the impact of the Great American Biotic Interchange on patterns of local richness in Lower Middle America and adjacent regions. We analyse data on species richness at 83 sites and a time-calibrated phylogeny for 363 species. We find no evidence for saturation, and show instead that biotic interchange dramatically increased local richness in the region. We suggest that historical biogeography offers thousands of similar long-term natural experiments that can be used to test for saturation. © 2014 John Wiley & Sons Ltd/CNRS.

  12. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten

    2012-01-01

    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation....

  13. Graph-analytical method for determining saturation in oil formations

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanova, E.E.; Fedortsov, V.K.; Ismaylov, K.K.

    1980-01-01

    Factual material is generalized for a large number of oil fields of the Soviet Union for which probability-statistical models have been selected. A graph-analytical method is developed for determining the saturation pressure of oil by gas.

  14. Delayed system control in presence of actuator saturation

    Directory of Open Access Journals (Sweden)

    A. Mahjoub

    2014-09-01

    Full Text Available The paper is introducing a new design method for systems’ controllers with input delay and actuator saturations and focuses on how to force the system output to track a reference input not necessarily saturation-compatible. We propose a new norm based on the way we quantify tracking performance as a function of saturation errors found using the same norm. The newly defined norm is related to signal average power making possible to account for most common reference signals e.g. step, periodic. It is formally shown that, whatever the reference shape and amplitude, the achievable tracking quality is determined by a well defined reference tracking mismatch error. This latter depends on the reference rate and its compatibility with the actuator saturation constraint. In fact, asymptotic output-reference tracking is achieved in the presence of constraint-compatible step-like references.

  15. Double storey three phase saturated cores fault current limiter

    Science.gov (United States)

    Wolfus, Y.; Nikulshin, Y.; Friedman, A.; Yeshurun, Y.

    2014-05-01

    A novel saturated-cores Fault-Current-Limiter (FCL) configuration is described. This FCL is based on two parallel planes of iron rectangular cores, on which three-phase coils are mounted and connected in series to the grid. Two DC coils are mounted in between the planes on perpendicular core limbs connecting the two AC planes. The DC coils are set to magnetically saturate the AC cores. The transition to three-dimensional, double-storey design enables handling three-phase symmetrical faults while offering better decoupling between the AC and DC circuits. At the same time, it shortens the AC limb lengths and enables deeper magnetic saturation levels in comparison to other saturated cores FCL designs. Hence, this FCL configuration exhibits lower insertion impedance and higher ratio of fault to nominal state impedance in comparison with other designs.

  16. Soil hydraulic properties near saturation, an improved conductivity model

    DEFF Research Database (Denmark)

    Børgesen, Christen Duus; Jacobsen, Ole Hørbye; Hansen, Søren

    2006-01-01

    The hydraulic properties near saturation can change dramatically due to the presence of macropores that are usually difficult to handle in traditional pore size models. The purpose of this study is to establish a data set on hydraulic conductivity near saturation, test the predictive capability...... of commonly used hydraulic conductivity models and give suggestions for improved models. Water retention and near saturated and saturated hydraulic conductivity were measured for a variety of 81 top and subsoils. The hydraulic conductivity models by van Genuchten [van Genuchten, 1980. A closed-form equation...... for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44, 892–898.] (vGM) and Brooks and Corey, modified by Jarvis [Jarvis, 1991. MACRO—A Model of Water Movement and Solute Transport in Macroporous Soils. Swedish University of Agricultural Sciences. Department of Soil Sciences...

  17. Saturation of entropy production in quantum many-body systems

    Science.gov (United States)

    Kaneko, Kazuya; Iyoda, Eiki; Sagawa, Takahiro

    2017-12-01

    Bridging the second law of thermodynamics and microscopic reversible dynamics has been a longstanding problem in statistical physics. Here, we address this problem on the basis of quantum many-body physics, and discuss how the entropy production saturates in isolated quantum systems under unitary dynamics. First, we rigorously prove that the entropy production does indeed saturate in the long time regime, even when the total system is in a pure state. Second, we discuss the non-negativity of the entropy production at saturation, implying the second law of thermodynamics. This is based on the eigenstate thermalization hypothesis, which states that even a single energy eigenstate is thermal. We also numerically demonstrate that the entropy production saturates at a non-negative value even when the initial state of a heat bath is a single energy eigenstate. Our results reveal fundamental properties of the entropy production in isolated quantum systems at late times.

  18. Retinal oxygen saturation before and after glaucoma surgery.

    Science.gov (United States)

    Nitta, Eri; Hirooka, Kazuyuki; Shimazaki, Takeru; Sato, Shino; Ukegawa, Kaori; Nakano, Yuki; Tsujikawa, Akitaka

    2017-08-01

    This study compared retinal vessel oxygen saturation before and after glaucoma surgery. Retinal oxygen saturation in glaucoma patients was measured using a non-invasive spectrophotometric retinal oximeter. Adequate image quality was found in 49 of the 108 consecutive glaucoma patients recruited, with 30 undergoing trabeculectomy, 11 EX-PRESS and eight trabeculotomy. Retinal oxygen saturation measurements in the retinal arterioles and venules were performed at 1 day prior to and at approximately 10 days after surgery. Statistical analysis was performed using a Student's t-test. After glaucoma surgery, intraocular pressure (IOP) decreased from 19.8 ± 7.7 mmHg to 9.0 ± 5.7 mmHg (p glaucoma surgery had an effect on the retinal venous oxygen saturation. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  19. On the Stability Criterion in a Saturated Atmosphere

    National Research Council Canada - National Science Library

    Richiardone, R; Giusti, F

    2001-01-01

      The expression of the moist buoyancy frequency indicated that it is not completely correct ot use the moist adiabatic lapse rate as a static stability parameter of a saturated atmosphere, because...

  20. Nonlinear Gain Saturation in Active Slow Light Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated.......We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated....

  1. Simulation of Nonlinear Gain Saturation in Active Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2012-01-01

    In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated.......In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated....

  2. Noise and saturation properties of semiconductor quantum dot optical amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper

    2002-01-01

    We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved.......We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved....

  3. Succinct synthesis of saturated hydroxy fatty acids and

    DEFF Research Database (Denmark)

    Kaspersen, Mads Holmgaard; Jenkins, Laura; Dunlop, Julia

    2017-01-01

    Saturated hydroxy fatty acids make up a class of underexplored lipids with potentially interesting biological activities. We report a succinct and general synthetic route to saturated hydroxy fatty acids hydroxylated at position 6 or higher, and exemplify this with the synthesis of hydroxylauric...... acids. All regioisomers of hydroxylauric acids were tested on free fatty acid receptors FFA1, FFA4 and GPR84. The results show that the introduction of a hydroxy group and its position have a high impact on receptor activity....

  4. Facile and Green Synthesis of Saturated Cyclic Amines.

    Science.gov (United States)

    Hameed, Arruje; Javed, Sadia; Noreen, Razia; Huma, Tayyaba; Iqbal, Sarosh; Umbreen, Huma; Gulzar, Tahsin; Farooq, Tahir

    2017-10-12

    Single-nitrogen containing saturated cyclic amines are an important part of both natural and synthetic bioactive compounds. A number of methodologies have been developed for the synthesis of aziridines, azetidines, pyrrolidines, piperidines, azepanes and azocanes. This review highlights some facile and green synthetic routes for the synthesis of unsubstituted, multisubstituted and highly functionalized saturated cyclic amines including one-pot, microwave assisted, metal-free, solvent-free and in aqueous media.

  5. Facile and Green Synthesis of Saturated Cyclic Amines

    Directory of Open Access Journals (Sweden)

    Arruje Hameed

    2017-10-01

    Full Text Available Single-nitrogen containing saturated cyclic amines are an important part of both natural and synthetic bioactive compounds. A number of methodologies have been developed for the synthesis of aziridines, azetidines, pyrrolidines, piperidines, azepanes and azocanes. This review highlights some facile and green synthetic routes for the synthesis of unsubstituted, multisubstituted and highly functionalized saturated cyclic amines including one-pot, microwave assisted, metal-free, solvent-free and in aqueous media.

  6. Biodegradation of crude oil saturated fraction supported on clays.

    Science.gov (United States)

    Ugochukwu, Uzochukwu C; Jones, Martin D; Head, Ian M; Manning, David A C; Fialips, Claire I

    2014-02-01

    The role of clay minerals in crude oil saturated hydrocarbon removal during biodegradation was investigated in aqueous clay/saturated hydrocarbon microcosm experiments with a hydrocarbon degrading microorganism community. The clay minerals used for this study were montmorillonite, palygorskite, saponite and kaolinite. The clay mineral samples were treated with hydrochloric acid and didecyldimethylammonium bromide to produce acid activated- and organoclays respectively which were used in this study. The production of organoclay was restricted to only montmorillonite and saponite because of their relative high CEC. The study indicated that acid activated clays, organoclays and unmodified kaolinite, were inhibitory to biodegradation of the hydrocarbon saturates. Unmodified saponite was neutral to biodegradation of the hydrocarbon saturates. However, unmodified palygorskite and montmorillonite were stimulatory to biodegradation of the hydrocarbon saturated fraction and appears to do so as a result of the clays' ability to provide high surface area for the accumulation of microbes and nutrients such that the nutrients were within the 'vicinity' of the microbes. Adsorption of the saturated hydrocarbons was not significant during biodegradation.

  7. The relation between oxygen saturation level and retionopathy of prematurity

    Directory of Open Access Journals (Sweden)

    Mohammad Gharavi Fard

    2016-03-01

    Full Text Available Introduction: Oxygen therapy used for preterm infant disease might be associated with oxygen toxicity or oxidative stress. The exact oxygen concentration to control and maintain the arterial oxygen saturation balance is not certainly clear. We aimed to compare the efficacy of higher or lower oxygen saturations on the development of severe retinopathy of prematurity which is a major cause of blindness in preterm neonates. Methods: PubMed was searched for obtaining the relevant articles. A total of seven articles were included after studying the titles, abstracts, and the full text of retrieved articles at initial search. Inclusion criteria were all the English language human clinical randomized controlled trials with no time limitation, which studied the efficacy of low versus high oxygen saturation measured by pulse oximetry in preterm infants.Result: It can be suggested that lower limits of oxygen saturations have higher efficacy at postmesetural age of ≤28 weeks in preterm neonates. This relation has been demonstrated in five large clinical trials including three Boost trials, COT, and Support.Discussion: Applying higher concentrations of oxygen supplementations at mesentural age ≥32 weeks reduced the development of retinopathy of prematurity. Lower concentrations of oxygen saturation decreased the incidence and the development of retinopathy of prematurity in preterm neonates while applied soon after the birth.Conclusions: Targeting levels of oxygen saturation in the low or high range should be performed cautiously with attention to the postmesentural age in preterm infants at the time of starting the procedures.

  8. Phase behavior and nanoscale structure of phospholipid membranes incorporated with acylated C-14-peptides

    DEFF Research Database (Denmark)

    Pedersen, T.B.; Kaasgaard, Thomas; Jensen, M.O.

    2005-01-01

    The thermotropic phase behavior and lateral structure of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers containing an acylated peptide has been characterized by differential scanning calorimetry (DSC) on vesicles and atomic force microscopy (AFM) on mica-supported bilayers. The acylated...... gel phase DPPC bilayers, inserts preferentially into preexisting defect regions and has a noticeable influence on the organization of the surrounding lipids. The presence of the C-14-peptide gives rise to a laterally heterogeneous bilayer structure with coexisting lipid domains characterized by a 10...

  9. Central venous oxygen saturation does not correlate with the venous oxygen saturation at the surgical site during abdominal surgery.

    Science.gov (United States)

    Weinrich, Malte; Scheingraber, Stefan; Stephan, Bernhard; Weiss, Christel; Kayser, Anna; Kopp, Berit; Schilling, Martin K

    2008-01-01

    Measurement of central venous oxygen saturation has become a surrogate parameter for fluid administration, blood transfusions and treatment with catecholamines in (early) goal directed therapy in the treatment of acute septic patients. These strategies are not easily transferred to the postoperative management of abdominal surgery due to the different conditions in surgical patients. A study population of 15 patients (8 females/7 males) underwent elective major abdominal surgery: 6 gastrectomies, 5 major liver resections and 4 lower anterior rectum resections. Surgery was performed for primary or secondary malignancy. The patients' age was 65.4+/-12.7 (mean+/-standard deviation, range 44-84, median 62) years. Blood samples were taken intraoperatively from indwelling central venous lines as well as from draining veins at the surgical site. Blood gas analyses to determine the oxygen saturations were performed immediately. All patients were operated in standardized general anesthesia including epidural analgesia and in a balanced volume status. Central venous oxygen saturations and oxygen saturations in blood from the draining veins of the surgical site showed a wide range with high intra- and interindividual differences intraoperatively. Overall, at most time points no correlation between the two oxygen saturations could be detected in three operation types. A significant correlation was only observed at one time point during liver resections. Our results show a lack of correlation between central venous oxygen saturations and oxygen saturations in the draining veins of the surgical site during major abdominal surgery. Measurement of central venous oxygen saturations does not seem to be a good surrogate for the local oxygen supply in the field of interest in major abdominal surgery even under standardized conditions.

  10. On the water saturation calculation in hydrocarbon sandstone reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Stalheim, Stein Ottar

    2002-07-01

    The main goal of this work was to identify the most important uncertainty sources in water saturation calculation and examine the possibility for developing new S{sub w} - equations or possibility to develop methods to remove weaknesses and uncertainties in existing S{sub w} - equations. Due to the need for industrial applicability of the equations we aimed for results with the following properties: The accuracy in S{sub w} should increase compared with existing S{sub w} - equations. The equations should be simple to use in petrophysical evaluations. The equations should be based on conventional logs and use as few as possible input parameters. The equations should be numerical stable. This thesis includes an uncertainty and sensitivity analysis of the most common S{sub w} equations. The results are addressed in chapter 3 and were intended to find the most important uncertainty sources in water saturation calculation. To increase the knowledge of the relationship between R{sub t} and S{sub w} in hydrocarbon sandstone reservoirs and to understand how the pore geometry affects the conductivity (n and m) of the rock a theoretical study was done. It was also an aim to examine the possibility for developing new S{sub w} - equations (or investigation an effective medium model) valid inhydrocarbon sandstone reservoirs. The results are presented in paper 1. A new equation for water saturation calculation in clean sandstone oil reservoirs is addressed in paper 2. A recommendation for best practice of water saturation calculation in non water wet formation is addressed in paper 3. Finally a new equation for water saturation calculation in thinly interbedded sandstone/mudstone reservoirs is presented in paper 4. The papers are titled: 1) Is the saturation exponent n a constant. 2) A New Model for Calculating Water Saturation In 3) Influence of wettability on water saturation modeling. 4) Water Saturation Calculations in Thinly Interbedded Sandstone/mudstone Reservoirs. A

  11. Menopausal estrogen therapy predicts better nocturnal oxyhemoglobin saturation.

    Science.gov (United States)

    Saaresranta, Tarja; Polo-Kantola, Päivi; Virtanen, Irina; Vahlberg, Tero; Irjala, Kerttu; Polo, Olli

    2006-10-20

    The respiratory responses in the few previous studies evaluating the effects of short-term unopposed estrogen therapy on breathing in postmenopausal women have been inconsistent. We performed a study to investigate whether long-term estrogen therapy would prevent age-related decline in nocturnal arterial oxyhemoglobin saturation and whether higher serum estradiol concentration is associated with better arterial oxyhemoglobin saturation. Sixty-four healthy postmenopausal women were followed-up for 5 years in a 5-year prospective open follow-up study. The women were users or non-users of estrogen therapy according to their personal preference. Mean overnight arterial oxyhemoglobin saturation was similar at baseline (94.3 +/- 1.1%) and after follow-up (94.5 +/- 1.6%). Present estrogen users had higher mean arterial oxyhemoglobin saturation (95.2 +/- 1.4%) than present non-users (94.0 +/- 1.5%), when adjusted for age and body mass index (p = 0.042). The change in mean arterial oxyhemoglobin saturation during follow-up was not associated with serum estradiol concentration at baseline but associated with estradiol at follow-up (p = 0.042), when adjusted for age and body mass index. At follow-up, women with higher serum estradiol concentration had also higher mean nocturnal arterial oxyhemoglobin saturation (Pearson r = 0.29, p = 0.019) and lower apnea-hypopnea index (Spearman r = -0.28, p = 0.031). The pooled current estrogen users spent proportionally less time with SaO(2) below 90% than non-users (ANCOVA adjusted for age and BMI, p = 0.017). Estrogen use and especially high serum estradiol concentration predict higher mean overnight arterial oxyhemoglobin saturation. The present data suggest that estrogen therapy has favorable respiratory effects.

  12. Why doesn't the ring current injection rate saturate?

    Science.gov (United States)

    Lopez, R. E.; Lyon, J. G.; Mitchell, E.; Bruntz, R.; Merkin, V. G.; Brogl, S.; Toffoletto, F.; Wiltberger, M.

    2009-02-01

    For low values of the solar wind electric field, the response of the polar cap potential is essentially linear, but at high values of VB s, the polar cap potential saturates and does not increase further with increasing VB s. On the other hand, the ring current injection rate does increase linearly with VB s and shows no evidence of saturating. If enhanced convection is the origin of the ring current, this poses a paradox. How can the polar cap potential, and thus convection, saturate when the ring current does not? We examine a possible explanation based on the reexamination of the Burton equation by Vasyliunas (2006). We show that this explanation is not a viable solution to the paradox since it would require a changing polar cap flux, and we demonstrate that the polar cap flux saturates (at around 1 GWb) as the polar cap potential saturates. Instead, we argue that during storms a quasi-steady reconnection region forms in the tail near the Earth. This reconnection region moves closer to the Earth for higher values of solar wind B s, although the polar cap potential, the dayside merging and nightside reconnection rates, and the amount of open flux do not change much as a function of B s once the polar cap potential has become saturated. As the neutral line moves closer, the volume per unit magnetic flux in the closed field line region is less. Flux tubes leaving the reconnection region in general have lower PV γ as B s increases, and lower PV γ flux tubes can penetrate deeper into the inner magnetosphere, leading to a corresponding greater injection of particles into the inner magnetosphere. Thus a reconnection region that is closer to Earth is more effective in creating a strong ring current. This leads to a continued dependence of the ring current injection rate on VB s, although the polar cap potential has saturated.

  13. Optimal sampling schedule for chemical exchange saturation transfer.

    Science.gov (United States)

    Tee, Y K; Khrapitchev, A A; Sibson, N R; Payne, S J; Chappell, M A

    2013-11-01

    The sampling schedule for chemical exchange saturation transfer imaging is normally uniformly distributed across the saturation frequency offsets. When this kind of evenly distributed sampling schedule is used to quantify the chemical exchange saturation transfer effect using model-based analysis, some of the collected data are minimally informative to the parameters of interest. For example, changes in labile proton exchange rate and concentration mainly affect the magnetization near the resonance frequency of the labile pool. In this study, an optimal sampling schedule was designed for a more accurate quantification of amine proton exchange rate and concentration, and water center frequency shift based on an algorithm previously applied to magnetization transfer and arterial spin labeling. The resulting optimal sampling schedule samples repeatedly around the resonance frequency of the amine pool and also near to the water resonance to maximize the information present within the data for quantitative model-based analysis. Simulation and experimental results on tissue-like phantoms showed that greater accuracy and precision (>30% and >46%, respectively, for some cases) were achieved in the parameters of interest when using optimal sampling schedule compared with evenly distributed sampling schedule. Hence, the proposed optimal sampling schedule could replace evenly distributed sampling schedule in chemical exchange saturation transfer imaging to improve the quantification of the chemical exchange saturation transfer effect and parameter estimation. Copyright © 2013 Wiley Periodicals, Inc.

  14. Symbolic Computation of Strongly Connected Components Using Saturation

    Science.gov (United States)

    Zhao, Yang; Ciardo, Gianfranco

    2010-01-01

    Finding strongly connected components (SCCs) in the state-space of discrete-state models is a critical task in formal verification of LTL and fair CTL properties, but the potentially huge number of reachable states and SCCs constitutes a formidable challenge. This paper is concerned with computing the sets of states in SCCs or terminal SCCs of asynchronous systems. Because of its advantages in many applications, we employ saturation on two previously proposed approaches: the Xie-Beerel algorithm and transitive closure. First, saturation speeds up state-space exploration when computing each SCC in the Xie-Beerel algorithm. Then, our main contribution is a novel algorithm to compute the transitive closure using saturation. Experimental results indicate that our improved algorithms achieve a clear speedup over previous algorithms in some cases. With the help of the new transitive closure computation algorithm, up to 10(exp 150) SCCs can be explored within a few seconds.

  15. Amplifying mirrors with saturated gain without and with a resonator

    DEFF Research Database (Denmark)

    Skettrup, Torben

    2007-01-01

    An investigation of amplifying mirrors with a view to their use in resonator structures has been performed. Both non-saturated and saturated amplifying mirrors are demonstrated. It was found that relatively high values of gain (typical 5-10 times) can be obtained even when saturation is taken...... into account. Several resonator structures containing from two up to four mirrors, some including beamsplitters, are investigated. It was found that the gain to a first approximation depends only on the ratio between the pumping power and the input power on the amplifying mirror. It was also found...... that the configuration with four mirrors is well suited as an amplifier device working as an optical transistor since high values of gain up to 40 times could be obtained....

  16. An analysis of the saturation of a high gain FEL

    Energy Technology Data Exchange (ETDEWEB)

    Gluckstern, R.L.; Okamoto, Hiromi (Maryland Univ., College Park, MD (United States). Dept. of Physics); Krinsky, S. (Brookhaven National Lab., Upton, NY (United States))

    1992-12-01

    We study the saturated state of an untapered free electron laser in the Compton regime, arising after exponential amplification of an initial low level of radiation by an initially monoenergetic, unbunched electron beam. The saturated state of the FEL is described by oscillations about an equilibrium state. Using the two invariants of the motion, and certain assumptions motivated by computer simulations, we provide approximate analytic descriptions of the radiation field and electron distribution in the saturation regime. We first consider a one-dimensional approximation, and later extend our approach to treat an electron beam of finite radial extent. Of note is a result on the radiated power in the case of an electron beam with small radius.

  17. Prediction of saturation using the carbon/oxygen log

    Energy Technology Data Exchange (ETDEWEB)

    Horner, S.C.; Sanyal, S.K.

    1984-09-01

    This project investigates the nature of Dresser-Atlas Carbon/Oxygen Log gamma ray spectra. It presents an attempt to improve the signal-to-noise ratio of the C/O and Si/Ca parameters used by Dresser-Atlas to determine oil saturation. Two techniques were developed to subtract the Compton background from the spectral data. Neither technique significantly improves the accuracy of the cased-hole prediction of oil saturation. However, it has been shown that it is possible to develop a satisfactory correlation for oil saturation on a well-by-well basis. This correlation can then be used to generate oil-in-place from the C/O and Si/Ca ratios. 17 references.

  18. Determining the Porosity and Saturated Hydraulic Conductivity of Binary Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. F.; Ward, Anderson L.; Keller, Jason M.

    2009-09-27

    Gravels and coarse sands make up significant portions of some environmentally important sediments, while the hydraulic properties of the sediments are typically obtained in the laboratory using only the fine fraction (e.g., <2 mm or 4.75 mm). Researchers have found that the content of gravel has significant impacts on the hydraulic properties of the bulk soils. Laboratory experiments were conducted to measure the porosity and the saturated hydraulic conductivity of binary mixtures with different fractions of coarse and fine components. We proposed a mixing-coefficient model to estimate the porosity and a power-averaging method to determine the effective particle diameter and further to predict the saturated hydraulic conductivity of binary mixtures. The proposed methods could well estimate the porosity and saturated hydraulic conductivity of the binary mixtures for the full range of gravel contents and was successfully applied to two data sets in the literature.

  19. Mutual boosting of the saturation scales in colliding nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kopeliovich, B.Z., E-mail: bzk@mpi-hd.mpg.d [Departamento de Fisica, Universidad Tecnica Federico Santa Maria, Instituto de Estudios Avanzados en Ciencias e Ingenieria, Centro Cientifico-Tecnologico de Valparaiso, Casilla 110-V, Valparaiso (Chile); Institut fuer Theoretische Physik der Universitaet, Philosophenweg 19, 69120 Heidelberg (Germany); Pirner, H.J. [Institut fuer Theoretische Physik der Universitaet, Philosophenweg 19, 69120 Heidelberg (Germany); Potashnikova, I.K.; Schmidt, Ivan [Departamento de Fisica, Universidad Tecnica Federico Santa Maria, Instituto de Estudios Avanzados en Ciencias e Ingenieria, Centro Cientifico-Tecnologico de Valparaiso, Casilla 110-V, Valparaiso (Chile)

    2011-03-14

    Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. The DGLAP driven gluon distribution turns out to be suppressed at large x, but significantly enhanced at x<<1. This is a high twist effect. In the case of nucleus-nucleus collisions all participating nucleons on both sides get enriched in gluon density at small x, which leads to a further boosting of the saturation scale. We derive reciprocity equations for the saturation scales corresponding to a collision of two nuclei. The solution of these equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of Q{sub sA}{sup 2}, in AA compared with pA collisions.

  20. SHAD-Nisat: A Composite Study of Shallow Saturation Diving Incorporating Long Duration Air Saturation with Excursions, Deep Nitrox Saturation, and Switch from Nitrogen to Helium

    Science.gov (United States)

    1982-08-01

    exposures caused red blood cell losses; recovery began a few days after return to normal pressure. The divers were also deconditioned , presumably...5. Deconditioning following long saturation 1-15 6. Pulmonary function changes 1-15 7. Sickness in 7 atm nitrox 1-16 8. Performance and...II-l 1. Chamber system II-l a. Physical characteristics II-l b. Air supply system II-4 c. Pure gas supply II-4 d. Pressurization and

  1. Saturated Zone Flow and Transport Expert Elicitation Project

    Energy Technology Data Exchange (ETDEWEB)

    Coppersmith, Kevin J.; Perman, Roseanne C.

    1998-01-01

    This report presents results of the Saturated Zone Flow and Transport Expert Elicitation (SZEE) project for Yucca Mountain, Nevada. This project was sponsored by the US Department of Energy (DOE) and managed by Geomatrix Consultants, Inc. (Geomatrix), for TRW Environmental Safety Systems, Inc. The DOE's Yucca Mountain Site Characterization Project (referred to as the YMP) is intended to evaluate the suitability of the site for construction of a mined geologic repository for the permanent disposal of spent nuclear fuel and high-level radioactive waste. The SZEE project is one of several that involve the elicitation of experts to characterize the knowledge and uncertainties regarding key inputs to the Yucca Mountain Total System Performance Assessment (TSPA). The objective of the current project was to characterize the uncertainties associated with certain key issues related to the saturated zone system in the Yucca Mountain area and downgradient region. An understanding of saturated zone processes is critical to evaluating the performance of the potential high-level nuclear waste repository at Yucca Mountain. A major goal of the project was to capture the uncertainties involved in assessing the saturated flow processes, including uncertainty in both the models used to represent the physical processes controlling saturated zone flow and transport, and the parameter values used in the models. So that the analysis included a wide range of perspectives, multiple individual judgments were elicited from members of an expert panel. The panel members, who were experts from within and outside the Yucca Mountain project, represented a range of experience and expertise. A deliberate process was followed in facilitating interactions among the experts, in training them to express their uncertainties, and in eliciting their interpretations. The resulting assessments and probability distributions, therefore, provide a reasonable aggregate representation of the knowledge and

  2. Asymmetric gain-saturated spectrum in fiber optical parametric amplifiers

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Rottwitt, Karsten; Galili, Michael

    2012-01-01

    We demonstrate experimentally and numerically an unexpected spectral asymmetry in the saturated-gain spectrum of single-pump fiber optical parametric amplifiers. The interaction between higher-order four-wave mixing products and dispersive waves radiated as an effect of third-order dispersion...... influences the energy transfer to the signal, depending on its detuning with respect to the pump, and breaks the symmetry of the gain expected from phase-matching considerations in unsaturated amplifiers. The asymmetry feature of the saturated spectrum is shown to particularly depend on the dispersion...... characteristics of the amplifier and shows local maxima for specific dispersion values....

  3. Saturation of the Holographic Principle for Spatially Closed Cosmological Models

    Science.gov (United States)

    Diaz, P.; Per, M. A.; Segui, A.

    Under the assumption on the fundamental character of the Holographic Principle as a primary principle guiding the behavior of our universe the saturation of the holographic limit is reasonable. On the other hand the Fischler-Susskind holographic prescription seems to be incompatible with closed cosmological models due to the apparently unavoidable recontraction of the particle horizon area. However we will show that the saturation of the Fischler-Susskind holographic prescription over a closed (although almost flat) cosmological model enforces a cosmological evolution very similar to the observed universe.

  4. Saturation Physics and the Electron-Ion Collider

    Science.gov (United States)

    Gonçalves, V. P.; Kugeratski, M. S.; Navarra, F. S.

    Using an extension of the Iancu-Itakura-Munier model to nuclear targets we look for saturation effects in electron-ion collisions. In previous publications we have made definite predictions. Here we try to compare our results with already existing experimental data on structure functions and on total and diffractive cross sections. Strictly speaking such a comparison is not well justified because the present data are not yet in the saturation domain. Nevertheless our results agree qualitatively with data and, in some cases, even quantitatively.

  5. Atmospheric sugar alcohols: evaporation rates and saturation vapor pressures

    DEFF Research Database (Denmark)

    Bilde, Merete; Zardini, Alessandro Alessio; Hong, Juan

    volatile organic molecules. Saturation vapor pressure and the associated temperature dependence (dH) are key parameters for improving predictive atmospheric models. In this work we combine experiments and thermodynamic modeling to investigate these parameters for a series of polyols, so-called sugar...... are allowed to evaporate in a laminar flow reactor, and changes in particle size as function of evaporation time are determined using a scanning mobility particle sizer system. In this work saturation vapor pressures of sugar alcohols at several temperatures have been inferred from such measurements using...

  6. Analysis on Inductance and Torque of PMSM Considering Magnetic Saturation

    Science.gov (United States)

    Cao, Xiao-Hua; Wang, Xin; Wei, Heng

    2017-07-01

    This paper analyses the surface-mounted PMSM which controlled by Id=0 vector control based on Ansoft in which finite element simulation of 2D static magnetic field can be operated on, then calculating and analysing the data with MATLAB, and then operating on the analysis of the change law of torque and inductance under different load conditions, and then paying more attention on the impact of magnetic saturation to torque and inductance. With the analysis of magnetic saturation, this paper puts forward a scheme of control and design used by PMSM.

  7. Robust human intrusion detection technique using hue-saturation histograms

    Science.gov (United States)

    Hassan, Waqas; Mitra, Bhargav; Bangalore, Nagachetan; Birch, Philip; Young, Rupert; Chatwin, Chris

    2011-04-01

    A robust human intrusion detection technique using hue-saturation histograms is presented in this paper. Initially a region of interest (ROI) is manually identified in the scene viewed by a single fixed CCTV camera. All objects in the ROI are automatically demarcated from the background using brightness and chromaticity distortion parameters. The segmented objects are then tracked using correlation between hue-saturation based bivariate distributions. The technique has been applied on all the 'Sterile Zone' sequences of the United Kingdom Home Office iLIDS dataset and its performance is evaluated with over 70% positive results.

  8. particle size distribution and control on bitumen saturation of some ...

    African Journals Online (AJOL)

    vicadmin

    The bitumen saturation analysis was carried out with the use of toluene. The result of sedimentological and particle size distribution studies showed that the sands are medium grained, moderately sorted and mesokurtic. The grain morphology can be described as having low to high sphericity, with shapes generally ...

  9. Article size distribution and control on Bitumen saturation of some ...

    African Journals Online (AJOL)

    The bitumen saturation analysis was carried out with the use of toluene. The result of sedimentological and particle size distribution studies showed that the sands are medium grained, moderately sorted and mesokurtic. The grain morphology can be described as having low to high sphericity, with shapes generally ...

  10. Investigation of paramagnetic saturation in lanthanum manganese nitrate

    NARCIS (Netherlands)

    Flokstra, Jakob; Meijer, H.C.; Bots, G.J.C.; Verheij, W.A.; van der Marel, L.C.

    1973-01-01

    Paramagnetic saturation of lanthanum manganese nitrate, La2Mn3(NO3)12·24H2O, has been investigated at liquid He temperatures in a static as well as a dynamical way. With the aid of the molecular-field theory the Casimir and Du Pré dispersion and absorption curves are adapted explicitly to the

  11. Effect of dietary lipid saturation on the production performance of ...

    African Journals Online (AJOL)

    Patron Saint of Ladybugs

    Dietary lipid saturation level had no effect on daily feed intake of hens, hen-day egg production, egg output and live weight of hens during the peak-of-lay period. The mono-unsaturated n-9 diet (high oleic acid sunflower oil) had the lowest feed efficiency (0.47), while that of the control-, polyunsaturated n-6. (sunflower oil) ...

  12. Enhancement of aromatic and saturated hydrocarbon by modified ...

    African Journals Online (AJOL)

    Three sediment samples collected from the Qua Iboe River System and eighteen different column packing ratios of silica gel and alumina were used in this investigation. The variation of the composition of the stationary phase (silica gel and alumina, SA) gave different yields of aromatic and saturated hydrocarbons. In all the ...

  13. Poole-Frenkel (PF) effect high field saturation

    OpenAIRE

    Ongaro, R.; Pillonnet, A.

    1989-01-01

    An improved Poole Frenkel (PF) effect, based upon a rigorous methodological approach, is proposed. The chosen model is stated precisely, emphasis being made explicitly on the subtending hypotheses. A systematic reference to Fermi-Dirac function, allows to establish quantitatively the concept of PF saturation. The resulting general theory integrates, as particular applications, the previous one-dimensional PF theories.

  14. Transport of E. coli in saturated and unsaturated porous media ...

    Indian Academy of Sciences (India)

    Saturated and unsaturated sand and soil column experiments were conducted to study the complex interaction between the effects of biological and hydrological factors on the transport of bacteria through a porous medium. These experiments were conducted with continuous input of bacteria and substrate at the inlet to ...

  15. Central venous oxygen saturation during hypovolaemic shock in humans

    DEFF Research Database (Denmark)

    Madsen, P; Iversen, H; Secher, N H

    1993-01-01

    We compared central venous oxygen saturation and central venous pressure (CVP) as indices of the effective blood volume during 50 degrees head-up tilt (anti-Trendelenburg's position) induced hypovolaemic shock in eight healthy subjects. Head-up tilt increased thoracic electrical impedance from 31...

  16. Rheology of dry, partially saturated and wet granular materials

    NARCIS (Netherlands)

    Pakpour, M.

    2013-01-01

    This thesis is dedicated to the study of the rheology of dry, wet and partially saturated granular materials. Granular media, suspensions, emulsions, polymers and gels are ubiquitous in the chemical and materials processing industry, and despite their very different appearance, the rheology and

  17. Organogel as a replacement of saturated fat in food products

    Science.gov (United States)

    Organogels of edible oil have drawn a great interest as promising alternatives to saturated fats and trans fats. Plant waxes are recognized as promising organogelators, which can provide organogels from healthful vegetable oils at low concentrations. Plant waxes are obtained as by-products during th...

  18. Experimental Validation of the Invariance of Electrowetting Contact Angle Saturation

    NARCIS (Netherlands)

    Chevalliot, S.; Dhindsa, M.; Kuiper, S.; Heikenfeld, J.

    2011-01-01

    Basic electrowetting theory predicts that a continued increase in applied voltage will allow contact angle modulation to zero degrees. In practice, the effect of contact angle saturation has always been observed to limit the contact angle modulation, often only down to a contact angle of 60 to 70°.

  19. Effect of soil saturation on denitrification in a grassland soil

    Directory of Open Access Journals (Sweden)

    L. M. Cardenas

    2017-10-01

    Full Text Available Nitrous oxide (N2O is of major importance as a greenhouse gas and precursor of ozone (O3 destruction in the stratosphere mostly produced in soils. The soil-emitted N2O is generally predominantly derived from denitrification and, to a smaller extent, nitrification, both processes controlled by environmental factors and their interactions, and are influenced by agricultural management. Soil water content expressed as water-filled pore space (WFPS is a major controlling factor of emissions and its interaction with compaction, has not been studied at the micropore scale. A laboratory incubation was carried out at different saturation levels for a grassland soil and emissions of N2O and N2 were measured as well as the isotopocules of N2O. We found that flux variability was larger in the less saturated soils probably due to nutrient distribution heterogeneity created from soil cracks and consequently nutrient hot spots. The results agreed with denitrification as the main source of fluxes at the highest saturations, but nitrification could have occurred at the lower saturation, even though moisture was still high (71 % WFSP. The isotopocules data indicated isotopic similarities in the wettest treatments vs. the two drier ones. The results agreed with previous findings where it is clear there are two N pools with different dynamics: added N producing intense denitrification vs. soil N resulting in less isotopic fractionation.

  20. Effect Of Intraruminal Infussion Of Saturated And Unsaturated Fatty ...

    African Journals Online (AJOL)

    This study describes the effect of intraruminal infusion of diferent proportions of palmitic (saturated fatty acid) and linolenic (unsaturated fatty acid) on rumen degradability of organic matter fraction of Pennisetium purpureum, total volatile fatty acid and total methane productions in West African Dwarf sheep. Five combination ...

  1. Facilitated transport of copper with hydroxyapatite nanoparticles in saturated sand

    Science.gov (United States)

    Saturated packed column experiments were conducted to investigate the facilitated transport of Cu with hydroxyapatite nanoparticles (nHAP) at different pore water velocities (0.22-2.2 cm min–1), solution pH (6.2-9.0), and fraction of Fe oxide coating on grain surfaces (', 0-0.36). The facilitated tr...

  2. 79 lung function, oxygen saturation and symptoms among street ...

    African Journals Online (AJOL)

    admin

    Therefore, a study of lung function, oxygen saturation and symptoms among female street sweepers and their control groups in Calabar, Nigeria was carried out. Ventilatory function tests were done using 200 female street sweepers whose length of service was less than two years and 200 sex, age, weight, and height ...

  3. Hydrocarbon saturation determination using acoustic velocities obtained through casing

    Science.gov (United States)

    Moos, Daniel

    2010-03-09

    Compressional and shear velocities of earth formations are measured through casing. The determined compressional and shear velocities are used in a two component mixing model to provides improved quantitative values for the solid, the dry frame, and the pore compressibility. These are used in determination of hydrocarbon saturation.

  4. Surface waves in a cylindrical borehole through partially-saturated ...

    Indian Academy of Sciences (India)

    48

    2017-01-04

    Jan 4, 2017 ... 1. Introduction. 40. The propagation of seismic waves in saturated porous media and related phenomena are of. 41 great interest in various fields, viz. acoustics, biomechanics, structural engineering, seismology. 42 and exploration of subsurface resources. Pores and fractures are pervasive in almost all the.

  5. Effect of soil saturation on denitrification in a grassland soil

    Science.gov (United States)

    Maritza Cardenas, Laura; Bol, Roland; Lewicka-Szczebak, Dominika; Gregory, Andrew Stuart; Matthews, Graham Peter; Whalley, William Richard; Misselbrook, Thomas Henry; Scholefield, David; Well, Reinhard

    2017-10-01

    Nitrous oxide (N2O) is of major importance as a greenhouse gas and precursor of ozone (O3) destruction in the stratosphere mostly produced in soils. The soil-emitted N2O is generally predominantly derived from denitrification and, to a smaller extent, nitrification, both processes controlled by environmental factors and their interactions, and are influenced by agricultural management. Soil water content expressed as water-filled pore space (WFPS) is a major controlling factor of emissions and its interaction with compaction, has not been studied at the micropore scale. A laboratory incubation was carried out at different saturation levels for a grassland soil and emissions of N2O and N2 were measured as well as the isotopocules of N2O. We found that flux variability was larger in the less saturated soils probably due to nutrient distribution heterogeneity created from soil cracks and consequently nutrient hot spots. The results agreed with denitrification as the main source of fluxes at the highest saturations, but nitrification could have occurred at the lower saturation, even though moisture was still high (71 % WFSP). The isotopocules data indicated isotopic similarities in the wettest treatments vs. the two drier ones. The results agreed with previous findings where it is clear there are two N pools with different dynamics: added N producing intense denitrification vs. soil N resulting in less isotopic fractionation.

  6. Mulching an Arenic Hapludult at Umudike: Effects on saturated ...

    African Journals Online (AJOL)

    A study was carried out over two cropping seasons on an Arenic Hapludult at Umudike, southeastern Nigeria, to investigate and determine the quantity and type of mulch material that would optimize the rhizome yield of turmeric (Curcuma longa Linn) and improve the saturated hydraulic conductivity of the soil. The turmeric ...

  7. A characterization of saturated fusion systems over abelian 2-groups

    DEFF Research Database (Denmark)

    Henke, Ellen

    2014-01-01

    Given a saturated fusion system FF over a 2-group S, we prove that S is abelian provided any element of S  is F-conjugate to an element of Z(S). This generalizes a Theorem of Camina–Herzog, leading to a significant simplification of its proof. More importantly, it follows that any 2-block B...

  8. Test of the rosetta pedotransfer function for saturated hydraulic conductivity

    NARCIS (Netherlands)

    Alvarez-Acosta, C.; Lascano, R.J.; Stroosnijder, L.

    2012-01-01

    Simulation models are tools that can be used to explore, for example, effects of cultural practices on soil erosion and irrigation on crop yield. However, often these models require many soil related input data of which the saturated hy- draulic conductivity (Ks) is one of the most important ones.

  9. Total mortality by elevated transferrin saturation in patients with diabetes

    DEFF Research Database (Denmark)

    Ellervik, Christina; Andersen, Henrik Ullits; Tybjærg-Hansen, Anne

    2013-01-01

    It is not known to what extent iron overload predicts prognosis in patients with diabetes after diagnosis or whether iron overload is a risk factor independent of the HFE genotype. We investigated total and cause-specific mortality according to increased transferrin saturation (≥ 50 vs....

  10. Surface waves in a cylindrical borehole through partially-saturated ...

    Indian Academy of Sciences (India)

    M D Sharma

    2018-02-14

    Feb 14, 2018 ... Keywords. Cylindrical waves; phase velocity; dispersion; porous solid; partial saturation; multiphase pore-fluid. Nomenclature t. Time ... on Biot's theory of poroelasticity (Biot 1956), was observed. In a later study, Chao et al. ... model and used it to obtain the analytical solution for wave propagation in a 1-D ...

  11. Upscaling soil saturated hydraulic conductivity from pore throat characteristics

    Science.gov (United States)

    Upscaling and/or estimating saturated hydraulic conductivity Ksat at the core scale from microscopic/macroscopic soil characteristics has been actively under investigation in the hydrology and soil physics communities for several decades. Numerous models have beendeveloped based on different approac...

  12. Sahlgren's saturation test for detecting and grading acquired dyschromatopsia.

    Science.gov (United States)

    Frisén, L; Kalm, H

    1981-08-01

    A new sorting test requires only two minutes for quantitative estimation of saturation thresholds for bluish pigment colors. The test is highly sensitive to and specific for differences between normal subjects and individuals with acquired color vision defects. When combined with Ishihara's pseudo-isochromatic plates, it discriminates between congenital and acquired dyschromatopsias and identifies subjects with combined defects.

  13. A saturating chiral field theory of nuclear matter

    Directory of Open Access Journals (Sweden)

    J. Boguta

    1983-01-01

    Full Text Available Catastrophe Theory analysis is used to construct a chiral theory of pions which leads to a saturating nuclear matter equation of state. This is achieved by introducing a vector meson field via the Higgs mechanism. The equation of state and the nuclear optical potential are computed. A metamorphosis of the nuclear force is suggested.

  14. Structural information from OH stretching frequencies monohydric saturated alcohols

    NARCIS (Netherlands)

    Maas, J.H. van der; Lutz, E.T.G.

    1974-01-01

    Infrared data have been recorded of the hydroxyl stretching band for about 70 monohydric saturated alcohols in dilute carbon tetrachloride solution. The wavenumber maximum, the half-bandwidth and the band pattern could be related to the structure of the molecules. Not only primary, secondary and

  15. Effect of saturation on seed dormancy and germination of the ...

    African Journals Online (AJOL)

    laddiya

    2012-01-26

    Jan 26, 2012 ... the lixiviated solutions, their germination, but not their growth and development, was inhibited. Taken together, this work provides valuable insight into the regulation of seed dormancy and germination rate in L. chinensis, which may in turn have implications for improved propagation. Key words: Saturation ...

  16. Centrifuge modeling of LNAPL transport in partially saturated sand

    NARCIS (Netherlands)

    Esposito, G.; Allersma, H.G.B.; Selvadurai, A.P.S.

    1999-01-01

    Model tests were performed at the Geotechnical Centrifuge Facility of Delft University of Technology, The Netherlands, to examine the mechanics of light nonaqueous phase liquid (LNAPL) movement in a partially saturated porous granular medium. The experiment simulated a 2D spill of LNAPL in an

  17. Shear waves in a fluid saturated elastic plate

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    MS received 25 February 2002. Abstract. In the present context, we consider the propagation of shear waves in the transverse isotropic fluid saturated porous plate. The frequency spectrum for SH-modes in the plate has been studied. It is observed that the frequency of the propagation is damped due to the two-phase ...

  18. Double shock dynamics induced by the saturation of defocusing nonlinearities

    KAUST Repository

    Crosta, Matteo

    2012-01-01

    We show that the saturation of defocusing nonlinearities leads to qualitative changes in the onset of wave breaking, determining double shock formation whose regularization occurs in terms of antidark solitons. In a given material, the crossover between different regimes can be controlled by changing the input intensity. © 2012 Optical Society of America.

  19. Calcium phosphate saturation in seawater around the Andaman Island

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.; Reddy, C.V.G.

    apparent solubility product of 4 x 10/20 C given by Kester and Pytocowicz. The maximum percentage saturation works out to be 67, 65, 95, and 97 respectively towards west, east, north and south. The inorganic mineral phosphate and calcium content...

  20. Saturating interactions in /sup 4/He with density dependence

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, S.D.; Resler, D.A.; Moszkowski, S.A.

    1989-05-03

    With the advent of larger and faster computers, as well as modern shell model codes, nuclear structure calculations for the light nuclei (A<16) which include full 2/bar h/..omega.. model spaces are quite feasible. However, there can be serious problems in the mixing of 2/bar h/..omega.. and higher excitations into the low-lying spectra if the effective interaction is non-saturating. Furthermore, effective interactions which are both saturating and density dependent have not generally been used in previous nuclear structure calculations. Therefore, we have undertaken studies of /sup 4/He using two-body potential interactions which incorporate both saturation and density-dependence. Encouraging initial results in remedying the mixing of 0 and 2/bar h/..omega.. excitations have been obtained. We have also considered the effects of our interaction on the /sup 4/He compressibility and the centroid of the breathing mode strength. First indications are that a saturating effective interaction, with a short-range density dependent part and a long-range density independent part, comes close to matching crude predictions for the compressibility of /sup 4/He. 11 refs., 6 tabs.

  1. Saturate hydraulic conductivity, water stable aggregates and soil ...

    African Journals Online (AJOL)

    Saturate hydraulic conductivity, water stable aggregates and soil organic matter in a sandy-loam soil in Ikwuano lga of Abia state. ... Samples were analyzed for soil properties like; Ksat, WSA (%) and percent organic carbon (OC %), Data from the analysis were subjected to ANOVA using a split plot in RCBD. Results ...

  2. Modelling suction instabilities in soils at varying degrees of saturation

    Directory of Open Access Journals (Sweden)

    Buscarnera Giuseppe

    2016-01-01

    Full Text Available Wetting paths imparted by the natural environment and/or human activities affect the state of soils in the near-surface, promoting transitions across different regimes of saturation. This paper discusses a set of techniques aimed at quantifying the role of hydrologic processes on the hydro-mechanical stability of soil specimens subjected to saturation events. Emphasis is given to the mechanical conditions leading to coupled flow/deformation instabilities. For this purpose, energy balance arguments for three-phase systems are used to derive second-order work expressions applicable to various regimes of saturation. Controllability analyses are then performed to relate such work input with constitutive singularities that reflect the loss of strength under coupled and/or uncoupled hydro-mechanical forcing. A suction-dependent plastic model is finally used to track the evolution of stability conditions in samples subjected to wetting, thus quantifying the growth of the potential for coupled failure modes upon increasing degree of saturation. These findings are eventually linked with the properties of the field equations that govern pore pressure transients, thus disclosing a conceptual link between the onset of coupled hydro-mechanical failures and the evolution of suction with time. Such results point out that mathematical instabilities caused by a non-linear suction dependent behaviour play an important role in the advanced constitutive and/or numerical tools that are commonly used for the analysis of geomechanical problems in the unsaturated zone, and further stress that the relation between suction transients and soil deformations is a key factor for the interpretation of runaway failures caused by intense saturation events.

  3. Stochastic Modeling of Macrodispersion in Variably Saturated, Spatially Heterogeneous Formations

    Science.gov (United States)

    Russo, David

    2015-04-01

    The macrodispersion tensor, D, plays an important role in solute transport on the field scale. A key problem is how to relate D to the properties of the spatially heterogeneous formation. Under unsaturated flow conditions, the problem is further complicated inasmuch as the relevant flow parameters, the hydraulic conductivity and the water capacity, which depend on the formation properties, depend also on flow-controlled attributes in a highly nonlinear fashion. Consequently, under variably saturated conditions, quantification of D requires several simplifying assumptions regarding the constitutive relationships for unsaturated flow, the flow regime, and the spatial structure of the formation heterogeneity. The present talk focuses on the quantification of D in a variably saturated, spatially heterogeneous formation, accomplished by using a two-stage approach. The approach combines a stochastic, continuum description of a steady-state unsaturated flow, based on small-perturbation, first-order approximation of Darcy's law and the continuity equation for unsaturated flow, with a general Lagrangian description of the motion of an indivisible particle of a passive solute that is carried by the steady-state flow. The resultant, time-dependent D depends on the covariances of the water saturation and the components of the water flux vector, and their cross-covariances, which, in turn, depend on the (cross-)covariances of the relevant formation properties and the pressure head. The effect of few characteristics of the spatially heterogeneous, variably saturated flow system, on D is analyzed and discussed. Main findings reveal that under variably saturated flow conditions, the travel distance required for the principal components of D to approach their asymptotic values may be exceedingly large, particularly in relatively wet formations with significant stratification and with coarse-textured soil material associated with small capillary forces. Hence, in many practical

  4. Reduction in saturated fat intake for cardiovascular disease.

    Science.gov (United States)

    Hooper, Lee; Martin, Nicole; Abdelhamid, Asmaa; Davey Smith, George

    2015-06-10

    Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally it is unclear whether the energy from saturated fats that are lost in the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein. This review is part of a series split from and updating an overarching review. To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA) or monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials. We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and EMBASE (Ovid) on 5 March 2014. We also checked references of included studies and reviews. Trials fulfilled the following criteria: 1) randomised with appropriate control group; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) not multifactorial; 4) adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 5) intervention at least 24 months; 6) mortality or cardiovascular morbidity data available. Two review authors working independently extracted participant numbers experiencing health outcomes in each arm, and we performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses and funnel plots. We include 15 randomised controlled trials (RCTs) (17 comparisons, ˜59,000 participants), which used a variety of interventions from providing all food to advice on how to reduce saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of cardiovascular events by 17% (risk ratio (RR) 0.83; 95% confidence interval (CI) 0.72 to 0.96, 13 comparisons, 53,300 participants of whom 8% had a cardiovascular event, I² 65%, GRADE moderate quality of

  5. Glycosaminoglycan chemical exchange saturation transfer in human lumbar intervertebral discs: Effect of saturation pulse and relationship with low back pain.

    Science.gov (United States)

    Wada, Tatsuhiro; Togao, Osamu; Tokunaga, Chiaki; Funatsu, Ryohei; Yamashita, Yasuo; Kobayashi, Kouji; Nakamura, Yasuhiko; Honda, Hiroshi

    2017-03-01

    To evaluate the dependence of saturation pulse power and duration on glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging and assess the degeneration of human lumbar intervertebral discs (IVDs) using this method. All images were acquired on a 3T magnetic resonance imaging (MRI) scanner. The CEST effects were measured in the glycosaminoglycan (GAG) phantoms with different concentrations. In the human study, CEST effects were measured in the nucleus pulposus of IVD. We compared the CEST effects among the different saturation pulse powers (0.4, 0.8, and 1.6 μT) or durations (0.5, 1.0, and 2.0 sec) at each Pfirrmann grade (I-V). The relationship between the CEST effects and low back pain was also evaluated. The phantom study showed high correlations between the CEST effects and GAG concentration (R 2  = 0.863, P low back pain were significantly lower than those in the groups without pain (P pain (P = 0.0216). The contrast of gagCEST imaging in the lumbar IVDs varied with saturation pulse power and duration. GagCEST imaging may serve as a tool for evaluating IVD degeneration in the lumbar spine. 2 J. Magn. Reson. Imaging 2017;45:863-871. © 2016 International Society for Magnetic Resonance in Medicine.

  6. TECHNIQUES OF EVALUATION OF HEMOGLOBIN OXYGEN SATURATION IN CLINICAL OPHTHALMOLOGY

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2016-01-01

    Full Text Available Oxygen content in body fluids and tissues is an important indicator of life support functions. A number of ocular pathologies, e.g. glaucoma, are of presumable vascular origin which means altered blood supply and oxygen circulation. Most oxygen is transported in the blood in the association with hemoglobin. When passing through the capillaries, hemoglobin releases oxygen, converting from oxygenated form to deoxygenated form. This process is accompanied by the changes in spectral characteristics of hemoglobin which result in different colors of arterial and venous blood. Photometric technique for the measurement of oxygen saturation in blood is based on the differences in light absorption by different forms of hemoglobin. The measurement of saturation is called oximetry. Pulse oximetry with assessment of tissue oxygenation is the most commonly used method in medicine. The degree of hemoglobin oxygen saturation in the eye blood vessels is the most accessible for noninvasive studies during ophthalmoscopy and informative. Numerous studies showed the importance of this parameter for the diagnosis of retinopathy of various genesis, metabolic status analysis in hyperglycemia, diagnosis and control of treatment of glaucoma and other diseases involving alterations in eye blood supply. The specific method for evaluation of oxygen concentration is the measurement of pressure of oxygen dissolved in the blood, i.e. partial pressure of oxygen. In ophthalmological practice, this parameter is measured in anterior chamber fluid evaluating oxygen level for several ophthalmopathies including different forms of glaucoma, for instillations of hypotensive eye drops as well as in vitreous body near to the optic disc under various levels of intraocular pressure. Currently, monitoring of oxygen saturation in retinal blood vessels, i.e. retinal oximetry, is well developed. This technique is based on the assessment of light absorption by blood depending on

  7. Complex geometrical optics of inhomogeneous and nonlinear saturable media

    Science.gov (United States)

    Berczynski, Pawel

    2013-05-01

    The method of complex geometrical optics (CGO) is presented, which describes Gaussian beam (GB) diffraction and self-focusing along curvilinear trajectory in smoothly inhomogeneous and nonlinear saturable media. CGO method reduces the problem of Gaussian beam propagation in inhomogeneous and nonlinear media to the system of the first order ordinary differential equations for the complex curvature of the wave front and for GB amplitude, which can be readily solved both analytically and numerically. As a result, CGO radically simplifies the description of Gaussian beam diffraction and self-focusing effects as compared to the other methods of nonlinear optics such as: variational method approach, method of moments and beam propagation method. The power of CGO method is presented on the example of the evolution of beam intensity and wave front cross-section along curvilinear central ray with torsion in weakly absorptive and nonlinear saturable graded-index fiber, where the effect of initial beam ellipticity is included into our description.

  8. Methane hydrate formation in partially water-saturated Ottawa sand

    Science.gov (United States)

    Waite, W.F.; Winters, W.J.; Mason, D.H.

    2004-01-01

    Bulk properties of gas hydrate-bearing sediment strongly depend on whether hydrate forms primarily in the pore fluid, becomes a load-bearing member of the sediment matrix, or cements sediment grains. Our compressional wave speed measurements through partially water-saturated, methane hydrate-bearing Ottawa sands suggest hydrate surrounds and cements sediment grains. The three Ottawa sand packs tested in the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) contain 38(1)% porosity, initially with distilled water saturating 58, 31, and 16% of that pore space, respectively. From the volume of methane gas produced during hydrate dissociation, we calculated the hydrate concentration in the pore space to be 70, 37, and 20% respectively. Based on these hydrate concentrations and our measured compressional wave speeds, we used a rock physics model to differentiate between potential pore-space hydrate distributions. Model results suggest methane hydrate cements unconsolidated sediment when forming in systems containing an abundant gas phase.

  9. Saturation wind power potential and its implications for wind energy.

    Science.gov (United States)

    Jacobson, Mark Z; Archer, Cristina L

    2012-09-25

    Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world's all-purpose power from wind in a 2030 clean-energy economy.

  10. Avalanche effect and gain saturation in high harmonic generation

    CERN Document Server

    Serrat, Carles; Budesca, Josep M; Seres, Jozsef; Seres, Enikoe; Aurand, Bastian; Hoffmann, Andreas; Namba, Shinichi; Kuehl, Thomas; Spielmann, Christian

    2015-01-01

    Optical amplifiers in all ranges of the electromagnetic spectrum exhibit two essential characteristics: i) the input signal during the propagation in the medium is multiplied by the avalanche effect of the stimulated emission to produce exponential growth and ii) the amplification saturates at increasing input signal. We demonstrate that the strong-field theory in the frame of high harmonic generation fully supports the appearance of both the avalanche and saturation effects in the amplification of extreme ultraviolet attosecond pulse trains. We confirm that the amplification takes place only if the seed pulses are perfectly synchronized with the driving strong field in the amplifier. We performed an experimental study and subsequent model calculation on He gas driven by intense 30-fs-long laser pulses, which was seeded with an attosecond pulse train at 110 eV generated in a separated Ne gas jet. The comparison of the performed calculations with the measurements clearly demonstrates that the pumped He gas med...

  11. Identifiability analysis of Prandtl Ishilinskii hysteresis model with saturation

    Science.gov (United States)

    Sjöström, MÅrten; Gulliksson, MÅrten

    2008-02-01

    A new class of Preisach operators based on play operators with an inverse in a closed form and allowing for saturation has recently been proposed. Its existence criteria and identification procedure were considered in earlier articles. The present paper analyses the identification procedure with respect to the sensitivity to underlying functions (i.e. intrinsic behaviour of the hysteretic system), to spline approximation, and to the least square error (LSE) estimation procedure. The analysis shows that model errors are significantly influenced by large derivatives of the underlying functions. Spline approximations have generally little effect on model errors. In particular, an upper bound of the relative parameter error due to measurement discrepancies has been derived for the LSE problem. The bound increases, the closer to saturation data are measured.

  12. Modeling saturable absorption for ultra short X-ray pulses

    Energy Technology Data Exchange (ETDEWEB)

    Hatada, Keisuke, E-mail: keisuke.hatada@unicam.it [CNISM, Sezione di Fisica, Scuola di Scienze e Tecnologie, Universit‘a di Camerino, via Madonna delle Carceri 9, I-62032 Camerino (Italy); INFN, Laboratori Nazionali di Frascati, 00044 Frascati (Italy); Di Cicco, Andrea [CNISM, Sezione di Fisica, Scuola di Scienze e Tecnologie, Universit‘a di Camerino, via Madonna delle Carceri 9, I-62032 Camerino (Italy)

    2014-10-15

    Saturable absorption was recently observed in transmission measurements above the L{sub II,III} edge of pure Al thin films using ultra short X-ray pulses at a free-electron-laser (FEL) facility. The high fluence reachable by FEL pulses, the shortness of the pulse duration, and the typical lifetime of the excited state are all important factors enabling observation of the phenomenon. We devised a simplified theoretical approach describing the saturation phenomenon using a three-channel model containing ground, excited and relaxed states. This phenomenological model explicitly includes the interaction between the solid and photon field in a semi-classical way, and the resulting non-linear coupled equation is solved numerically. We successfully applied this model to recent experimental results obtained using FEL radiation.

  13. Saturated virtual fluorescence emission difference microscopy based on detector array

    Science.gov (United States)

    Liu, Shaocong; Sun, Shiyi; Kuang, Cuifang; Ge, Baoliang; Wang, Wensheng; Liu, Xu

    2017-07-01

    Virtual fluorescence emission difference microscopy (vFED) has been proposed recently to enhance the lateral resolution of confocal microscopy with a detector array, implemented by scanning a doughnut-shaped pattern. Theoretically, the resolution can be enhanced by around 1.3-fold compared with that in confocal microscopy. For further improvement of the resolving ability of vFED, a novel method is presented utilizing fluorescence saturation for super-resolution imaging, which we called saturated virtual fluorescence emission difference microscopy (svFED). With a point detector array, matched solid and hollow point spread functions (PSF) can be obtained by photon reassignment, and the difference results between them can be used to boost the transverse resolution. Results show that the diffraction barrier can be surpassed by at least 34% compared with that in vFED and the resolution is around 2-fold higher than that in confocal microscopy.

  14. Continuous central venous saturation monitoring in pediatrics: a case report.

    Science.gov (United States)

    Spenceley, Neil; Skippen, Peter; Krahn, Gordon; Kissoon, Niranjan

    2008-03-01

    To report the use of a new pediatric central venous catheter that offers continuous central venous saturation (ScVO2) monitoring in the critically ill child. Case report. Pediatric intensive care unit in a tertiary care children's hospital. A 3-month-old child, following cardiac surgery, with an isolated decrease in central venous saturations. Diagnosis of pericardial effusion by echocardiography followed by surgical drainage. ScVO2 readings quickly returned to normal, and the remaining patient course was uneventful. We report the first case of a newly modified central venous catheter (PediaSat Oximetry Catheter, Edwards Lifesciences LLC, Irvine, CA) for children and demonstrate its utility in a patient with impaired oxygen delivery when traditional markers remain stable. This catheter enabled the rapid diagnosis of cardiac compromise due to pericardial effusion, leading to early treatment. Traditional central catheter functions and insertion technique are maintained, making the catheter potentially useful in any critically ill child.

  15. Red cell aspartate aminotransferase saturation with oral pyridoxine intake

    OpenAIRE

    Oshiro, Marilena; Nonoyama, Kimiyo; Oliveira, Raimundo Antônio Gomes; Barretto, Orlando Cesar de Oliveira

    2005-01-01

    CONTEXT AND OBJECTIVE: The coenzyme of aspartate aminotransferase is pyridoxal phosphate, generated from fresh vegetables containing pyridoxine. Vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronie’s syndrome respond to high pyridoxine doses. The objective was to investigate the oral pyridoxine oral dose that would lead to maximized pyridoxal phosphate saturation of red cell aspartate aminotransferase. DESIGN AND SETTING: Controlled trial, in Hematology Division of Instituto...

  16. Cellular and Molecular Imaging Using Chemical Exchange Saturation Transfer.

    Science.gov (United States)

    McMahon, Michael T; Gilad, Assaf A

    2016-10-01

    Chemical exchange saturation transfer (CEST) is a powerful new tool well suited for molecular imaging. This technology enables the detection of low concentration probes through selective labeling of rapidly exchanging protons or other spins on the probes. In this review, we will highlight the unique features of CEST imaging technology and describe the different types of CEST agents that are suited for molecular imaging studies, including CEST theranostic agents, CEST reporter genes, and CEST environmental sensors.

  17. SATURATED-SUBCOOLED STRATIFIED FLOW IN HORIZONTAL PIPES

    Energy Technology Data Exchange (ETDEWEB)

    Richard Schultz

    2010-08-01

    Advanced light water reactor systems are designed to use passive emergency core cooling systems with horizontal pipes that provide highly subcooled water from water storage tanks or passive heat exchangers to the reactor vessel core under accident conditions. Because passive systems are driven by density gradients, the horizontal pipes often do not flow full and thus have a free surface that is exposed to saturated steam and stratified flow is present.

  18. A Partially Saturated Constitutive Theory for Compacted Fills

    Science.gov (United States)

    2004-06-01

    excellent example of this is the work by Brackley (1975) who envisioned the grain structure of a partially saturated soil and therefore a means to explain...Josa, A., (1988). "Un modelo elastoplastico para suelos no saturados," Tesis Doctorae, Universitat Politecnica de Catalunya, Barcelons, Spain. Lawton...smech + icode IF(hflag(r)) hmech=bmnech + icode IF(tflag(r)) trnech=tmech + icode icode = 10*icode end do Print data for an Excel file Added for

  19. Parameter Identification Using ANFIS for Magnetically Saturated Induction Motor

    OpenAIRE

    Mohamed M. Ismail Ali; M. A. Moustafa Hassan

    2012-01-01

    The problem of controlling the p-model induction motor with magnetic saturation is considered in this paper. The motor parameters such that stator resistance Rs, rotor resistance Rr and load torque TL can be varied during the operation, many techniques are used for online identification of the motor parameters. In this paper, the authors use a new technique which is the Adaptive Neuro Fuzzy Inference Systems (ANFIS) technique for online identification of the motor parameters. A simulation stu...

  20. Saturated hydraulic conductivity (Ksat) in relation to some soil ...

    African Journals Online (AJOL)

    The results of the study showed that the particle size fractions of the soils varied from sandy loam to clay loam. Bulk density and particle density were low to moderate with mean values of 1.44 gcm-3 and 2.34 gcm-3. Total porosity was low with mean value of 38.06% and a coefficient of variation of 9.56%. Saturated hydraulic ...

  1. Postural control in a simulated saturation dive to 240 msw.

    OpenAIRE

    Goplen, Frederik Kragerud; Aasen, T. B.; Nordahl, Stein Helge G

    2007-01-01

    INTRODUCTION: There is evidence that increased ambient pressure causes an increase in postural sway. This article documents postural sway at pressures not previously studied and discusses possible mechanisms. METHODS: Eight subjects participated in a dry chamber dive to 240 msw (2.5 MPa) saturation pressure. Two subjects were excluded due to unilateral caloric weakness before the dive. Postural sway was measured on a force platform. The path length described by the center of pr...

  2. Phase field modeling of partially saturated deformable porous media

    Science.gov (United States)

    Sciarra, Giulio

    2016-09-01

    A poromechanical model of partially saturated deformable porous media is proposed based on a phase field approach at modeling the behavior of the mixture of liquid water and wet air, which saturates the pore space, the phase field being the saturation (ratio). While the standard retention curve is expected still^ to provide the intrinsic retention properties of the porous skeleton, depending on the porous texture, an enhanced description of surface tension between the wetting (liquid water) and the non-wetting (wet air) fluid, occupying the pore space, is stated considering a regularization of the phase field model based on an additional contribution to the overall free energy depending on the saturation gradient. The aim is to provide a more refined description of surface tension interactions. An enhanced constitutive relation for the capillary pressure is established together with a suitable generalization of Darcy's law, in which the gradient of the capillary pressure is replaced by the gradient of the so-called generalized chemical potential, which also accounts for the "force", associated to the local free energy of the phase field model. A micro-scale heuristic interpretation of the novel constitutive law of capillary pressure is proposed, in order to compare the envisaged model with that one endowed with the concept of average interfacial area. The considered poromechanical model is formulated within the framework of strain gradient theory in order to account for possible effects, at laboratory scale, of the micro-scale hydro-mechanical couplings between highly localized flows (fingering) and localized deformations of the skeleton (fracturing).

  3. Saturation of the Electric Field Transmitted to the Magnetosphere

    Science.gov (United States)

    Lyatsky, Wladislaw; Khazanov, George V.; Slavin, James A.

    2010-01-01

    We reexamined the processes leading to saturation of the electric field, transmitted into the Earth's ionosphere from the solar wind, incorporating features of the coupled system previously ignored. We took into account that the electric field is transmitted into the ionosphere through a region of open field lines, and that the ionospheric conductivity in the polar cap and auroral zone may be different. Penetration of the electric field into the magnetosphere is linked with the generation of the Alfven wave, going out from the ionosphere into the solar wind and being coupled with the field-aligned currents at the boundary of the open field limes. The electric field of the outgoing Alfven wave reduces the original electric field and provides the saturation effect in the electric field and currents during strong geomagnetic disturbances, associated with increasing ionospheric conductivity. The electric field and field-aligned currents of this Alfven wave are dependent on the ionospheric and solar wind parameters and may significantly affect the electric field and field-aligned currents, generated in the polar ionosphere. Estimating the magnitude of the saturation effect in the electric field and field-aligned currents allows us to improve the correlation between solar wind parameters and resulting disturbances in the Earth's magnetosphere.

  4. Saturated versus unsaturated hydrocarbon interactions with carbon nanostructures

    Directory of Open Access Journals (Sweden)

    Deivasigamani eUmadevi

    2014-09-01

    Full Text Available The interactions of various acyclic and cyclic hydrocarbons in both saturated and unsaturated forms with the carbon nanostructures (CNSs have been explored by using density functional theory (DFT calculations. Model systems representing armchair and zigzag carbon nanotubes (CNTs and graphene have been considered to investigate the effect of chirality and curvature of the CNSs towards these interactions. Results of this study reveal contrasting binding nature of the acyclic and cyclic hydrocarbons towards CNSs. While the saturated molecules show stronger binding affinity in acyclic hydrocarbons; the unsaturated molecules exhibit higher binding affinity in cyclic hydrocarbons. In addition, acyclic hydrocarbons exhibit stronger binding affinity towards the CNSs when compared to their corresponding cyclic counterparts. The computed results excellently corroborate the experimental observations. The interaction of hydrocarbons with graphene is more favourable when compared with CNTs. Bader’s theory of atoms in molecules has been invoked to characterize the noncovalent interactions of saturated and unsaturated hydrocarbons. Our results are expected to provide useful insights towards the development of rational strategies for designing complexes with desired noncovalent interaction involving CNSs.

  5. Evaluation of the Performance of Grouting Materials for Saturated Riprap

    Directory of Open Access Journals (Sweden)

    Daehyeon Kim

    2013-12-01

    Full Text Available In this study, four types of grout were developed to evaluate the effect of grouting of saturated riprap layers on ground water flow. The developed types of grout are divided into a quick-setting type and a general-type, and also into high and low viscosities. A number of grout tests were performed in a model acrylic chamber, 0.4 m in diameter and 2.0 m in length, for visual observation of injection. To reproduce the field flow condition of the saturated riprap layers (approach flow, the grout tests were carried out at 0 cm/s and 100 cm/s for the flow speed and 10 L/min for the grout injection speed after installing a flow injection opening on the lower part of the chamber. Based on the results of the grout tests, the injection of each grout in the saturated riprap layers was examined to find out the most effective grout.

  6. A mercury saturation assay for measuring metallothionein in fish

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, M.D. (Univ. of Manitoba, Winnipeg (Canada). Dept. of Zoology); Stephenson, M. (AECL Research, Pinawa, Manitoba (Canada). Environmental Science Branch); Klaverkamp, J.F. (Freshwater Inst., Winnipeg, Manitoba (Canada))

    1993-07-01

    An accurate, rapid, sensitive, and simple method using mercury saturation for quantifying metallothionein (MT) is described. A complex solution of enzymatic and nonenzymatic thiols, including rabbit liver MT-2, and supernatants from homogenized samples of rainbow trout liver were incubated in the presence of [sup 203]Hg in 10% trichloroacetic acid. Excess Hg was bound to an removed by chicken egg albumin, which denatured on contact with the acidic assay medium. After centrifugation, MT labeled with [sup 203]Hg remained in the TCA supernatant and was estimated using known stoichiometry for Hg-MT binding. A dilution series was used to establish that nonspecific metal binding, a common problem with other metal saturation assays, is negligible. Analysis of hepatic MT with high Cu content from rainbow trout demonstrated virtually complete displacement of Cu, Cd, and Zn by Hg. When compared to other metal-saturation assays developed for vertebrates, this method requires the least number of technical steps, and one-third or less of total preparatory and analytical time.

  7. World, Land, and High-Altitude Saturation Wind Power Potentials

    Science.gov (United States)

    Archer, C. L.; Jacobson, M. Z.

    2012-12-01

    Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. We use the GATOR-GCMOM global model, modified to treat wind turbines as an elevated momentum sink, to explore the effects of increasing the number of wind turbines over large geographic regions. Energy is conserved in the model by converting all electric power generated by the wind turbines to heat via electricity use at the surface, where it occurs, and by converting kinetic energy lost by natural surface roughness to turbulence, then heat. We find that, as the number of turbines is increased, power extraction first increases linearly, but then converges to a "saturation" potential not identified previously from physical principles or turbine properties. These saturation potentials are ~253 TW at 100 m hub height over the entire globe, ~80 TW at 100 m over land and near-shore (outside Antarctica), and ~380 TW at 10 km in the jet streams. Sensitivity to grid resolution is minimal. We propose that these saturation potentials should be used as the world, land, and high-altitude theoretical wind power potentials.

  8. Nonlinear mechanisms for drift wave saturation and induced particle transport

    Energy Technology Data Exchange (ETDEWEB)

    Dimits, A.M. (Maryland Univ., College Park, MD (USA). Lab. for Plasma Research); Lee, W.W. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

    1989-12-01

    A detailed theoretical study of the nonlinear dynamics of gyrokinetic particle simulations of electrostatic collisionless and weakly collisional drift waves is presented. In previous studies it was shown that, in the nonlinearly saturated phase of the evolution, the saturation levels and especially the particle fluxes have an unexpected dependence on collisionality. In this paper, the explanations for these collisionality dependences are found to be as follows: The saturation level is determined by a balance between the electron and ion fluxes. The ion flux is small for levels of the potential below an E {times} B-trapping threshold and increases sharply once this threshold is crossed. Due to the presence of resonant electrons, the electron flux has a much smoother dependence on the potential. In the 2-1/2-dimensional ( pseudo-3D'') geometry, the electrons are accelerated away from the resonance as they diffuse spatially, resulting in an inhibition of their diffusion. Collisions and three-dimensional effects can repopulate the resonance thereby increasing the value of the particle flux. 30 refs., 32 figs., 2 tabs.

  9. Cardiac arrhythmias during fiberoptic bronchoscopy and relation with oxygen saturation

    Directory of Open Access Journals (Sweden)

    Hassan G

    2005-01-01

    Full Text Available To evaluate the occurrence of electrocardiographic abnormalities during fiberoptic bronchoscopy, in relation to specific stages of the procedures, patients′ age, sex, smoking, pre-existing lung disease, premedication and oxygen saturation, a prospective study was conducted on 56 patients aged 35 to 75 (mean 62 years without pre-existing cardiovascular disease. Patients were connected to a 12-lead computerized electrocardiographic recorder and pulse oximeter. Fall of oxygen saturation from mean of 95.12% before the procedure to below 80% was observed in 12 (21.4% patients and below 75% in 5 (8.9% patients, at various stages. Statistically highly significant (p < 0.001 fall of oxygen saturation was observed during the procedures while bronchoscope was introduced into the airways and tracheobronchial tree examined. Major disturbances of cardiac rhythm (i.e. atrial, ventricular or both developed in 23 (41.07% patients. Out of these, sinus tachycardia was noted in 16 (69.5%, ventricular premature complexes in 5 (21.7% and paroxysmal supraventricular tachycardia in 2 (8.6% patients. Arrhythmias were most frequent in association with periods of maximum oxygen desaturation in 18 (78.2% of these 23 patients. Oxygen desaturation persisted for more than half an hour in 38 (67.8% of the 56 patients. However, no correlation was observed between the frequency of arrhythmias during bronchoscopy and patients′ age, sex pre-medication or pre-existing pulmonary disease.

  10. Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle

    2006-04-30

    During this last period of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we finalized integration of rock physics, well log analysis, seismic processing, and forward modeling techniques. Most of the last quarter was spent combining the results from the principal investigators and come to some final conclusions about the project. Also much of the effort was directed towards technology transfer through the Direct Hydrocarbon Indicators mini-symposium at UH and through publications. As a result we have: (1) Tested a new method to directly invert reservoir properties, water saturation, Sw, and porosity from seismic AVO attributes; (2) Constrained the seismic response based on fluid and rock property correlations; (3) Reprocessed seismic data from Ursa field; (4) Compared thin layer property distributions and averaging on AVO response; (5) Related pressures and sorting effects on porosity and their influence on DHI's; (6) Examined and compared gas saturation effects for deep and shallow reservoirs; (7) Performed forward modeling using geobodies from deepwater outcrops; (8) Documented velocities for deepwater sediments; (9) Continued incorporating outcrop descriptive models in seismic forward models; (10) Held an open DHI symposium to present the final results of the project; (11) Relations between Sw, porosity, and AVO attributes; (12) Models of Complex, Layered Reservoirs; and (14) Technology transfer Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and

  11. A Design Method of Saturation Test Image Based on CIEDE2000

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2012-01-01

    Full Text Available In order to generate color test image consistent with human perception in aspect of saturation, lightness, and hue of image, we propose a saturation test image design method based on CIEDE2000 color difference formula. This method exploits the subjective saturation parameter C′ of CIEDE2000 to get a series of test images with different saturation but same lightness and hue. It is found experimentally that the vision perception has linear relationship with the saturation parameter C′. This kind of saturation test image has various applications, such as in the checking of color masking effect in visual experiments and the testing of the visual effects of image similarity component.

  12. A customized resistivity system for monitoring saturation and seepage in earthen levees: installation and validation

    National Research Council Canada - National Science Library

    Diego Arosio; Stefano Munda; Greta Tresoldi; Monica Papini; Laura Longoni; Luigi Zanzi

    2017-01-01

    This work is based on the assumption that a resistivity meter can effectively monitor water saturation in earth levees and can be used as a warning system when saturation exceeds the expected seasonal maxima...

  13. Impact of sample saturation on the detected porosity of hardened concrete using low temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Johannesson, Björn

    2014-01-01

    The present work studied the impact of sample saturation on the analysis of pore volume and pore size distribution by low temperature (micro-)calorimetry. The theoretical background was examined, which emphasizes that the freezing/melting temperature of water/ice confined in non-fully saturated...... samples and a higher proportion of pores with small radii were found in the capillary saturated samples. In addition, the observed hysteresis between the freezing and melting curves of ice content of the capillary saturated samples was more pronounced than that of the vacuum saturated samples. The major...... pores is further depressed compared with that when the pores are fully saturated. The study of the experimental data on hardened concrete samples showed that for a same concrete mix, the total pore volume detected from the capillary saturated samples was always lower than that of the vacuum saturated...

  14. Magnesium Oxide Carbonation Rate Law in Saturated Brines

    Science.gov (United States)

    Nemer, M. B.; Allen, C.; Deng, H.

    2008-12-01

    Magnesium oxide (MgO) is the only engineered barrier certified by the EPA for emplacement in the Waste Isolation Pilot Plant (WIPP), a U.S. Department of Energy repository for transuranic waste in southeast New Mexico. MgO reduces actinide solubility by sequestering CO2 generated by the biodegradation of cellulosic, plastic, and rubber materials. Demonstration of the effectiveness of MgO is essential for WIPP recertification. In order to be an effective barrier, the rate of CO2 sequestration should be fast compared to the rate CO2 production, over the entire 10,000 year regulatory period. While much research has been conducted on the kinetics of magnesium oxide carbonation in waters with salinity up to that of sea water, we are not aware of any work on determining the carbonation rate law in saturated brines at low partial pressures of CO2 (PCO2 as low as 10-5.5 atm), which is important for performing safety assessments of bedded salt waste repositories. Using a Varian ion-trap gas- chromatograph/mass-spectrometer (GC/MS) we experimentally followed the CO2 sequestration kinetics of magnesium oxide in salt-saturated brines down to a PCO2 as low as 10-5.5 atm. This was performed in a closed reactor with a known initial PCO2. The results of this study show that carbonation is approximately first order in PCO2, in saturated brines. We believe that this method will benefit the study of the detailed kinetics of other similar processes.

  15. A New Robust Solver for Saturated-Unsaturated Richards' Equation

    Science.gov (United States)

    Barajas-Solano, D. A.; Tartakovsky, D. M.

    2012-12-01

    We present a novel approach for the numerical integration of the saturated-unsaturated Richards' equation, a degenerate parabolic partial differential equation that models flow in porous media. The method is based on the mixed (pore pressure-water content) form of RE, written as a set of differential algebraic equations (DAEs) of index-1 for the fully saturated case and index-2 for the partially saturated case. A DAE-based approach allows us to overcome the numerical challenges posed by the degenerate nature of the Richards' equation. The resulting set of DAEs is solved using the stiffly-accurate, single-step, 3-stage implicit Runge-Kutta method Radau IIA, chosen for its favorable accuracy and stability properties, and its ease of implementation. For each time step a nonlinear system of equations on the intermediate Runge-Kutta states of the pore pressure is solved, written so to ensure that the next step pore pressure and water content correspond to one another correctly. The implementation of our approach compares favorably to state-of-the-art DAE-based solvers in both one- and two-dimensional simulations. These solvers use multi-step backward difference formulas together with a pressure-based form of Richards' equation. To the best of our knowledge, our method is the first instance of a successful DAE-based solver that uses the mixed form of Richards' equation. We consider this a promising line of research, with future work to be done on the use of globally convergent methods for the solution of the occurring nonlinear systems of equations.

  16. Results of neutron irradiation of liquid lithium saturated with deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Tazhibayeva, Irina, E-mail: tazhibayeva@ntsc.kz [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Ponkratov, Yuriy; Kulsartov, Timur; Gordienko, Yuriy; Skakov, Mazhyn; Zaurbekova, Zhanna [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Lyublinski, Igor [JSC «Red Star», Moscow (Russian Federation); NRNU «MEPhI», Moscow (Russian Federation); Vertkov, Alexey [JSC «Red Star», Moscow (Russian Federation); Mazzitelli, Giuseppe [ENEA, RC Frascati, Frascati (Italy)

    2017-04-15

    Highlights: • The results on neutron irradiation of liquid lithium saturated with deuterium at the IVG.1M research reactor are described. • At temperatures below 573 K the efficiency coefficient of tritium release is well described by the expression K = 0.015 exp(−14/RT), and above 623 K − K = 10{sup 9} exp(−144/RT). • The T{sub 2} molecules contribution into the overall tritium release becomes apparent at temperatures higher than 673 K and increases with the temperature rise. - Abstract: This paper describes the results on neutron irradiation of liquid lithium saturated with deuterium at the IVG.1 M research reactor. The neutron flux at the reactor core center at 2 MW was 5 10{sup −13} cm{sup −2} s{sup −1}. The efficiency coefficients of helium and tritium release from lithium saturated with deuterium were calculated. The tritium interaction with lithium atoms (formation and dissociation of lithium tritide) has an effect on tritium release. An increment of sample’s temperature results in tritium release acceleration due to rising of the dissociation rate of lithium tritide. At temperatures below 573 K the efficiency coefficient of tritium release is well described by the expression K = 0.015 exp(−14/RT), and above 623 K − K = 10{sup 9} exp(-144/RT). The T{sub 2} molecules contribution into the overall tritium release becomes apparent at temperatures higher than 673 K and increases with the temperature rise.

  17. Experiment of nitrox saturation diving with trimix excursion.

    Science.gov (United States)

    Shi, Z Y

    1998-11-01

    Depth limitations to diving operation with air as the breathing gas are well known: air density, oxygen toxicity, nitrogen narcosis and requirement for decompression. The main objectives of our experiment were to assess the decompression, counterdiffusion and performance aspect of helium-nitrogen-oxygen excursions from nitrox saturation. The experiment was carried out in a wet diving stimulator with "igloo" attached to a 2-lock living chamber. Four subjects of two teams of 2 divers were saturated at 25 msw simulated depth in a nitrogen oxygen chamber environment for 8 days, during which period they performed 32 divers-excursions to 60 or 80 msw pressure. Excursion gas mix was trimix of 14.6% oxygen, 50% helium and 35.4% nitrogen, which gave a bottom oxygen partial pressure of 1.0 bars at 60 msw and 1.3 at 80 msw. Excursions were for 70 min at 60 msw with three 10-min work periods and 40 min at 80 msw with two 10-min work periods. Work was on a bicycle ergometer at a moderate level. We calculated the excursion decompression with M-Values based on methods of Hamilton (Hamilton et al., 1990). Staged decompression took 70 min for the 60 msw excursion and 98 min for 80 msw, with stops beginning at 34 or 43 msw respectively. After the second dive day bubbles were heard mainly in one diver but in three divers overall, to Spencer Grade III some times. No symptoms were reported. Saturation decompression using the Repex procedures began at 40 msw and was uneventful: Grade II and sometimes III bubbles persisted in 2 of the four divers until 24 hr after surfacing. We conclude that excursions with mixture rich in helium can be performed effectively to as deep as 80 msw using these procedures.

  18. Saturation Effect of Projectile Excitation in Ion-Atom Collisions

    Science.gov (United States)

    Mukoyama, Takeshi; Lin, Chii-Dong

    Calculations of projectile K-shell electron excitation cross sections for He-like ions during ion-atom collisions have been performed in the distortion approximation by the use of Herman-Skillman wave functions. The calculated results are compared with the experimental data for several targets. The excitation cross sections deviate from the first-Born approximation and show the saturation effect as a function of target atomic number. This effect can be explained as the distortion of the projectile electronic states by the target nucleus.

  19. Changes in hemodynamic parameters and cerebral saturation during supraventricular tachycardia.

    Science.gov (United States)

    Hershenson, Jared A; Ro, Pamela S; Miao, Yongjie; Tobias, Joseph D; Olshove, Vincent; Naguib, Aymen N

    2012-02-01

    Induced supraventricular tachycardia (SVT) during electrophysiology studies (EPS) can be associated with hemodynamic changes. Traditionally, invasive arterial blood pressure has been used for continuous monitoring of these changes. This prospective study evaluated the efficacy of near-infrared spectroscopy (NIRS) monitoring during SVT. The use of NIRS has expanded with evidence of its accuracy and benefit in detecting cerebral hypoperfusion. This study aimed first to determine the hemodynamic changes associated with electrophysiology testing for SVT and second to determine whether the hemodynamic changes are associated with similar changes in the cerebral saturation as determined by NIRS. The study enrolled 30 patients 5-20 years of age with a history of SVT who underwent an EPS. The demographic data included age, gender, weight, height, and type of SVT. Hemodynamic data (invasive blood pressure and heart rate), NIRS, bispectral index (BIS), end-tidal carbon dioxide, and pulse oximetry were collected before and during three episodes of induced SVT. The linear correlation coefficient (r) was measured to calculate the relationship of the changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) to the changes in NIRS values during the SVT episodes. Data from 22 patients were collected. The induction of SVT was associated mainly with a change in SBP and a less prominent change in DBP and MAP from baseline. The changes in hemodynamic status were associated with minimal changes in cerebral saturations, as evidenced by an average absolute change in NIRS of SVT during electrophysiology testing is associated with hemodynamic changes, mainly in SBP. In this study, these hemodynamic changes resulted in a minimal decrease in cerebral perfusion, as evidenced by minimal changes in the cerebral saturation measured by NIRS (0.7% from baseline). Although the changes in the cerebral saturation were minimal, these changes were

  20. Gain dynamics and saturation in semiconductor quantum dot amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper; Hvam, Jørn Märcher

    2004-01-01

    Quantum dot (QD)-based semiconductor optical amplifiers offer unique properties compared with conventional devices based on bulk or quantum well material. Due to the bandfilling properties of QDs and the existence of a nearby reservoir of carriers in the form of a wetting layer, QD semiconductor...... optical amplifiers may be operated in regimes of high linearity, i.e. with a high saturation power, but can also show strong and fast nonlinearities by breaking the equilibrium between discrete dot states and the continuum of wetting layer states. In this paper, we analyse the interplay of these two...

  1. Fabrication of PDMS/SWCNT thin films as saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Romano, I; Sanchez-Mondragon, J J [Photonics and Optical Physics Laboratory, Optics Department, INAOE Apdo. Postal 51 and 216, Tonantzintla, Puebla 72000 (Mexico); Davila-Rodriguez, J; Delfyett, P J [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, FL 32816-2700 (United States); May-Arrioja, D A, E-mail: hromano@inaoep.mx [Depto. de Ingenieria Electronica, UAM Reynosa Rodhe, Universidad Autonoma de Tamaulipas, Carr. Reynosa-San Fernando S/N, Reynosa, Tamaulipas 88779 (Mexico)

    2011-01-01

    We present a novel technique to fabricate a saturable absorber thin film based on Polydimethylsiloxane doped with Single Wall Carbon Nanotubes. Using this film a passive mode-locked fiber laser in a standard ring cavity configuration was built by inserting the film between two angled connectors. Self-starting passively mode-locked laser operation was easily observed. The generated pulses have a width of 1.26 ps at a repetition rate of 22.7 MHz with an average power of 4.89 mW.

  2. Low Saturation Intensities in Two-Photon Ultracold Collisions

    Science.gov (United States)

    Sukenik, C. I.; Hoffmann, D.; Bali, S.; Walker, T.

    1998-07-01

    We have observed violet photon emission resulting from energy-pooling collisions between ultracold Rb atoms illuminated by two colors of near-resonant infrared laser light. We have used this emission as a probe of doubly excited state ultracold collision dynamics. We have observed the lowest saturation intensity for light-induced ultracold collisions seen to date which we identify as due to depletion of incoming ground state flux. We have also varied the detuning of the lasers which allows us to clearly identify the effect of spontaneous emission and optical shielding.

  3. Monitoring cerebral tissue oxygen saturation during surgery: a clinician's perspective

    Science.gov (United States)

    Meng, Lingzhong; Gelb, Adrian W.; Cerussi, Albert E.; Mantulin, William W.; Tromberg, Bruce J.

    2013-03-01

    Organ protection and physiology optimization are important goals when taking care of anesthetized patients undergoing surgery. Postoperative cognitive dysfunction and perioperative stroke are unwarranted potential outcomes. Neurovascular coupling, the match between cerebral metabolic demand and substrate supply, should be regarded as the essential cerebral physiology which needs to be monitored during surgery. The brain-targeting near-infrared spectroscopy (NIRS) technology has the potential to fulfill this goal. Proposition of why and how to monitor essential cerebral physiology via advanced NIRS technologies is discussed. We also discussed the limits of the current NIRS technologies which merely measure cerebral tissue oxygen saturation in pooled cerebral arterial, capillary, and venous blood.

  4. Transformer ratio saturation in a beam-driven wakefield accelerator

    Science.gov (United States)

    Farmer, J. P.; Martorelli, R.; Pukhov, A.

    2015-12-01

    We show that for beam-driven wakefield acceleration, the linearly ramped, equally spaced train of bunches typically considered to optimise the transformer ratio only works for flat-top bunches. Through theory and simulation, we explain that this behaviour is due to the unique properties of the plasma response to a flat-top density profile. Calculations of the optimal scaling for a train of Gaussian bunches show diminishing returns with increasing bunch number, tending towards saturation. For a periodic bunch train, a transformer ratio of 23 was achieved for 50 bunches, rising to 40 for a fully optimised beam.

  5. Terahertz saturable absorbers from liquid phase exfoliation of graphite

    OpenAIRE

    Bianchi, Vezio; Carey, Tian; Viti, Leonardo; Li, Lianhe; Linfield, Edmund H.; Davies, A. Giles; Tredicucci, Alessandro; Yoon, Duhee; Karagiannidis, Panagiotis; Lombardi, Lucia; Tomarchio, Flavia; Ferrari, Andrea C.; Torrisi, Felice; Vitiello, Miriam S.

    2017-01-01

    Saturable absorbers (SA) operating at terahertz (THz) frequencies can open new frontiers in the development of passively mode-locked THz micro-sources. Here we report the fabrication of THz SAs by transfer coating and inkjet printing single and few-layer graphene films prepared by liquid phase exfoliation of graphite. Open-aperture z-scan measurements with a 3.5 THz quantum cascade laser show a transparency modulation ∼80%, almost one order of magnitude larger than that reported to date at TH...

  6. Spatiotemporal extreme events in a laser with a saturable absorber

    Science.gov (United States)

    Rimoldi, Cristina; Barland, Stéphane; Prati, Franco; Tissoni, Giovanna

    2017-02-01

    We study extreme events occurring in the transverse (x ,y ) section of the field emitted by a broad-area semiconductor laser with a saturable absorber. The spatiotemporal events on which we perform the statistical analysis are identified as maxima of the field intensity in the three-dimensional space (x ,y ,t ) . We identify regions in the parameter space where extreme events are more likely to occur and we study the connection of those extreme events with the cavity solitons that are known to exist in the same system, both stationary and self-pulsing.

  7. Formation of fatty acids in photochemical conversions of saturated hydrocarbons

    Science.gov (United States)

    Telegina, T. A.; Pavlovskaya, T. Y.; Ladyzhenskaya, A. I.

    1977-01-01

    Abiogenic synthesis of fatty acids was studied in photochemical conversions of saturated hydrocarbons. It was shown that, in a hydrocarbon water CaCO3 suspension, the action of 254 nm UV rays caused the formation of fatty acids with a maximum number of carbon atoms in the chain not exceeding that in the initial hydrocarbon. Synthesis of acetic, propionic, butyric, valeric, caproic, enanthic and caprylic (in the case of octane) acids occurs in heptane water CaCO3 and octane water CaCO3 systems.

  8. Sahlgren's Saturation Test for acquired dyschromatopsia: increased lightness enhances sensitivity.

    Science.gov (United States)

    Lindblom, B; Wikholm, M; Frisén, L

    1988-01-01

    Sahlgren's Saturation Test (SST) is a simple sorting test designed for the detection and grading of acquired color vision defects. Like other pigment-based color vision tests, the SST color samples have medium lightness, i.e., they belong to the intermediate part of the gray scale. We tested normal controls and subjects with congenital or acquired dyschromatopsia with five SST versions that differed only in the amount of lightness. The sensitivity of the test increased considerably with increasing lightness. Therefore, the lightness level of SST has now been changed from 30 to 10 Natural Color System units.

  9. Rate dependence of dry, oil- or water-saturated chalk

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Al-Alwan, A.

    The rate dependence of dry, oil- or water-saturated high-porosity outcrop chalk is investigated based on whether the fluid effect could be excluded from a governing material parameter, the b-factor. The b-factor is used in geotechnical engineering to establish the difference in evolution of load...... between stress-strain curves when applying different loading rates. The material investigated is outcrop chalk from Stevns, Southern part of Denmark, with a porosity of 43 to 44% and subjected to varying loading rates. The Biot critical frequency is a function of the fluid properties viscosity and density...

  10. Reverse saturable absorption (RSA) in fluorinated iridium derivatives

    Science.gov (United States)

    Ferry, Michael J.; O'Donnell, Ryan M.; Bambha, Neal; Ensley, Trenton R.; Shensky, William M.; Shi, Jianmin

    2017-08-01

    The photophysical properties of cyclometallated iridium compounds are beneficial for nonlinear optical (NLO) applications, such as the design of reverse saturable absorption (RSA) materials. We report on the NLO characterization of a family of compounds of the form [Ir(pbt)2(LX)], where pbt is 2-phenylbenzothiazole and LX is a beta-diketonate ligand. In particular, we investigate the effects of trifluoromethylation on compound solubility and photophysics compared to the parent acetylacetonate (acac) version. The NLO properties, such as the singlet and triplet excited-state cross sections, of these compounds were measured using the Z-scan technique. The excited-state lifetimes were determined from visible transient absorption spectroscopy.

  11. De-Mystifying Saturated Fats – A Perspective

    Directory of Open Access Journals (Sweden)

    Indu Mani

    2014-11-01

    Full Text Available Since the 1980s the world has been repeatedly informed about the harmful effects of saturated fatty acids. The USDA recommends that SFA consumption should be < 10 en%, while the American Heart Association goes a step further and suggests that the intakes should be reduced to < 7 en%. However, recent findings are increasingly questioning this advice, showing evidence that consumption of SFA may actually be better than increasing intake of either carbohydrates or polyunsaturated fatty acids. This article aims to summarize some of this information, with emphasis on its relevance to Indian diets.

  12. Monte Carlo simulation of AB-copolymers with saturating bonds

    DEFF Research Database (Denmark)

    Chertovich, A.C.; Ivanov, V.A.; Khokhlov, A.R.

    2003-01-01

    Structural transitions in a single AB-copolymer chain where saturating bonds can be formed between A- and B-units are studied by means of Monte Carlo computer simulations using the bond fluctuation model. Three transitions are found, coil-globule, coil-hairpin and globule-hairpin, depending...... on the nature of a particular AB-sequence: statistical random sequence, diblock sequence and 'random-complementary' sequence (one-half of such an AB-sequence is random with Bernoulli statistics while the other half is complementary to the first one). The properties of random-complementary sequences are closer...

  13. Nonlinear saturation of ballooning modes in tokamaks and stellarators

    Science.gov (United States)

    Bauer, F.; Garabedian, P.; Betancourt, O.

    1988-01-01

    The spectral code BETAS computes plasma equilibrium in a toroidal magnetic field B = [unk]s × [unk]Ψ with remarkable accuracy because the finite difference scheme employed in the radial direction allows for discontinuities of the flux function Ψ across the nested surfaces s = const. Instability of higher modes in stellarators like the Heliotron E can be detected in roughly an hour on the best supercomputers by calculating bifurcated equilibria that are defined over just one field period. The method has been validated by comparing results about nonlinear saturation of ballooning modes in tokamaks with numerical data from the PEST code. PMID:16593984

  14. Ligand partitioning into lipid bilayer membranes under high pressure: Implication of variation in phase-transition temperatures.

    Science.gov (United States)

    Matsuki, Hitoshi; Kato, Kentaro; Okamoto, Hirotsugu; Yoshida, Shuntaro; Goto, Masaki; Tamai, Nobutake; Kaneshina, Shoji

    2017-12-01

    The variation in phase-transition temperatures of dipalmitoylphosphatidylcholine (DPPC) bilayer membrane by adding two membrane-active ligands, a long-chain fatty acid (palmitic acid (PA)) and an inhalation anesthetic (halothane (HAL)), was investigated by light-transmittance measurements and fluorometry. By assuming the thermodynamic colligative property for the bilayer membrane at low ligand concentrations, the partitioning behavior of these ligands into the DPPC bilayer membrane was considered. It was proved from the differential partition coefficients between two phases that PA has strong affinity with the gel (lamellar gel) phase in a micro-molal concentration range and makes the bilayer membrane more ordered, while HAL has strong affinity with the liquid crystalline phase in a milli-molal concentration range and does the bilayer membrane more disordered. The transfer volumes of both ligands from the aqueous solution to each phase of the DPPC bilayer membrane showed that the preferential partitioning of the PA molecule into the gel (lamellar gel) produces about 20% decrease in transfer volume as compared with the liquid crystalline phase, whereas that of the HAL molecule into the liquid crystalline phase does about twice increase in transfer volume as compared with the gel (ripple gel) phase. Furthermore, changes in thermotropic and barotropic phase behavior of the DPPC bilayer membrane by adding the ligand was discussed from the viewpoint of the ligand partitioning. Reflecting the contrastive partitioning of PA and HAL into the pressure-induced interdigitated gel phase among the gel phases, it was revealed that PA suppresses the formation of the interdigitated gel phase under high pressure while HAL promotes it. These results clearly indicate that each phase of the DPPC bilayer membrane has a potential to recognize various ligand molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Pump-to-Signal Intensity Modulation Transfer in Saturated- Gain Fiber Optical Parametric Amplifiers

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Lund-Hansen, Toke; Rottwitt, Karsten

    2011-01-01

    The pump-to-signal intensity modulation transfer in saturated degenerate FOPAs is numerically investigated over the whole gain bandwidth. The intensity modulation transfer decreases and the OSNR improves when the amplifier operates in the saturation regime.......The pump-to-signal intensity modulation transfer in saturated degenerate FOPAs is numerically investigated over the whole gain bandwidth. The intensity modulation transfer decreases and the OSNR improves when the amplifier operates in the saturation regime....

  16. Inductance identification of an induction machine taking load-dependent saturation into account

    OpenAIRE

    Ranta, Mikaela; Hinkkanen, Marko; Luomi, Jorma

    2008-01-01

    The paper proposes an identification method for the inductances of induction machines, based on signal injection. Due to magnetic saturation, a saturation-induced saliency appears in the induction motor, and the total leakage inductance estimate depends on the angle of the excitation signal. The proposed identification method is based on a small-signal model that includes the saturation-induced saliency. Because of the saturation, the load also affects the estimate, and measurements are neede...

  17. Composition of the saturated hydrocarbons from males, females, and eggs of the millipede, Graphidostreptus tumuliporus

    NARCIS (Netherlands)

    Oudejans, R.C.H.M.

    The total hydrocarbons of the millipede Graphidostreptus tumuliporus contain 10 per cent saturated components. The composition of the saturated hydrocarbons from males, females, and eggs is reported. Straight-chain alkanes (n-C15–n-C36) constitute 59 to 75 per cent of the saturated hydrocarbons

  18. A novel approach to deterministic performance analysis of guidance loops with saturation

    NARCIS (Netherlands)

    Weiss, M.; Bucco, D.

    2011-01-01

    Since saturation often plays an important role in limiting the performance of guidance loops, performance analysis of guidance loops with saturation has been a popular subject of investigation. Most work so far has concentrated on the effect of saturation on stochastic performance of guidance loops,

  19. Relating the onset of reduction to degree of soil water saturation ...

    African Journals Online (AJOL)

    Relating the onset of reduction to degree of soil water saturation. Kimberly Smith, Cornelius W van Huyssteen. Abstract. Literature does not indicate the degree of water saturation at which reduction is expected to occur. This study therefore aimed to determine the degree of water saturation (S) at which reduction is initiated.

  20. A Modified Prophylactic Regimen for the Prevention of Otitis Externa in Saturation Divers

    Science.gov (United States)

    2013-10-01

    Prophylactic Regimen for the Prevention of Otitis Externa in Saturation Divers Authors: DISTRIBUTION STATEMENT A. Paul C. Algra, LT, MC...May 2012 – May 2013 4. TITLE AND SUBTITLE A Modified Prophylactic Regimen for the Prevention of Otitis Externa in Saturation Divers...SUPPLEMENTARY NOTES 14. ABSTRACT To prevent acute otitis externa (AOE) in the saturation setting and to decrease the side effects

  1. 9 CFR 96.14 - Uncertified casings; disinfection with saturated brine solution.

    Science.gov (United States)

    2010-01-01

    ... saturated brine solution. 96.14 Section 96.14 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... § 96.14 Uncertified casings; disinfection with saturated brine solution. Foreign animal casings offered... acid as at present or if preferred may be submerged in a saturated brine solution at a temperature not...

  2. Threshold Saturation in Spatially Coupled Constraint Satisfaction Problems

    Science.gov (United States)

    Hamed Hassani, S.; Macris, Nicolas; Urbanke, Ruediger

    2013-03-01

    We consider chains of random constraint satisfaction models that are spatially coupled across a finite window along the chain direction. We investigate their phase diagram at zero temperature using the survey propagation formalism and the interpolation method. We prove that the SAT-UNSAT phase transition threshold of an infinite chain is identical to the one of the individual standard model, and is therefore not affected by spatial coupling. We compute the survey propagation complexity using population dynamics as well as large degree approximations, and determine the survey propagation threshold. We find that a clustering phase survives coupling. However, as one increases the range of the coupling window, the survey propagation threshold increases and saturates towards the phase transition threshold. We also briefly discuss other aspects of the problem. Namely, the condensation threshold is not affected by coupling, but the dynamic threshold displays saturation towards the condensation one. All these features may provide a new avenue for obtaining better provable algorithmic lower bounds on phase transition thresholds of the individual standard model.

  3. Distinct saturable pathways for the endocytosis of different tyrosine motifs.

    Science.gov (United States)

    Warren, R A; Green, F A; Stenberg, P E; Enns, C A

    1998-07-03

    Endocytosis of surface proteins through clathrin-coated pits requires an internalization signal in the cytoplasmic domain. Two types of internalization signal have been described: one requiring a tyrosine as the critical residue (tyrosine-based motif), and the other consisting of either two consecutive leucines or an isoleucine and leucine (dileucine motif). Although it seems that these signals are necessary and sufficient for endocytic targeting, the mechanism of recognition is not well understood. To examine this question, tetracycline-repressible cell lines were used to overexpress one of several receptors bearing a tyrosine-based internalization signal. By measuring the rates of endocytosis for either the overexpressed receptor, or that of other endogenous receptors, we were able to show that the endocytosis of identical receptors could be saturated, but a complete lack of competition exists between the transferrin receptor (TfR), the low-density lipoprotein receptor, and the epidermal growth factor receptor. Overexpression of any one of these receptors resulted in its redistribution toward the cell surface, implying that entry into coated pits is limited. During high levels of TfR expression, however, a significant increase in the amount of surface Lamp1, but not low-density lipoprotein receptor, epidermal growth factor receptor, or Lamp2, is detected. This suggests that Lamp1 and TfR compete for the same endocytic sites. Together, these results support the idea that there are at least three distinct saturable components involved in clathrin-mediated endocytosis.

  4. Water Flow in Karst Aquifer Considering Dynamically Variable Saturation Conduit

    Science.gov (United States)

    Tan, Chaoqun; Hu, Bill X.

    2017-04-01

    The karst system is generally conceptualized as dual-porosity system, which is characterized by low conductivity and high storage continuum matrix and high conductivity and quick flow conduit networks. And so far, a common numerical model for simulating flow in karst aquifer is MODFLOW2005-CFP, which is released by USGS in 2008. However, the steady-state approach for conduit flow in CFP is physically impractical when simulating very dynamic hydraulics with variable saturation conduit. So, we adopt the method proposed by Reimann et al. (2011) to improve current model, in which Saint-Venant equations are used to model the flow in conduit. Considering the actual background that the conduit is very big and varies along flow path and the Dirichlet boundary varies with rainfall in our study area in Southwest China, we further investigate the influence of conduit diameter and outflow boundary on numerical model. And we also analyze the hydraulic process in multi-precipitation events. We find that the numerical model here corresponds well with CFP for saturated conduit, and it could depict the interaction between matrix and conduit during very dynamic hydraulics pretty well compare with CFP.

  5. Biodegradation of diesel/biodiesel blends in saturated sand microcosms

    DEFF Research Database (Denmark)

    Lisiecki, Piotr; Chrzanowski, Łukasz; Szulc, Alicja

    2014-01-01

    The aim of the study was to evaluate the biodegradation extent of both aromatic and aliphatic hydrocarbon fractions in saturated sandy microcosm spiked with diesel/biodiesel blends (D, B10, B20, B30, B40, B50, B60, B70, B80, B90 and B100, where D is commercial petroleum diesel fuel and B is comme......The aim of the study was to evaluate the biodegradation extent of both aromatic and aliphatic hydrocarbon fractions in saturated sandy microcosm spiked with diesel/biodiesel blends (D, B10, B20, B30, B40, B50, B60, B70, B80, B90 and B100, where D is commercial petroleum diesel fuel and B...... is commercial biodiesel blend) augmented with a bacterial consortium of petroleum degraders. The biodegradation kinetics for blends were evaluated based on measuring the amount of emitted CO2 after 578 days. Subsequently, the residual aromatic and aliphatic fractions were separated and determined by employing...... of biodiesel, regardless of the concentration used. This observation leads to the conclusion that blending with biodiesel does not impact the long-term biodegradation of specific diesel oil fractions. © 2013 Elsevier Ltd. All rights reserved....

  6. Analysis of a Heroin Epidemic Model with Saturated Treatment Function

    Directory of Open Access Journals (Sweden)

    Isaac Mwangi Wangari

    2017-01-01

    Full Text Available A mathematical model is developed that examines how heroin addiction spreads in society. The model is formulated to take into account the treatment of heroin users by incorporating a realistic functional form that “saturates” representing the limited availability of treatment. Bifurcation analysis reveals that the model has an intrinsic backward bifurcation whenever the saturation parameter is larger than a fixed threshold. We are particularly interested in studying the model’s global stability. In the absence of backward bifurcations, Lyapunov functions can often be found and used to prove global stability. However, in the presence of backward bifurcations, such Lyapunov functions may not exist or may be difficult to construct. We make use of the geometric approach to global stability to derive a condition that ensures that the system is globally asymptotically stable. Numerical simulations are also presented to give a more complete representation of the model dynamics. Sensitivity analysis performed by Latin hypercube sampling (LHS suggests that the effective contact rate in the population, the relapse rate of heroin users undergoing treatment, and the extent of saturation of heroin users are mechanisms fuelling heroin epidemic proliferation.

  7. Atom-field entanglement in cavity QED: Nonlinearity and saturation

    Science.gov (United States)

    Rogers, Robert; Cummings, Nick; Pedrotti, Leno M.; Rice, Perry

    2017-11-01

    We investigate the degree of entanglement between an atom and a driven cavity mode in the presence of dissipation. Previous work has shown that in the limit of weak driving fields, the steady-state entanglement is proportional to the square of the driving intensity. This quadratic dependence is due to the generation of entanglement by the creation of pairs of photons or excitations. In this work we investigate the entanglement between an atom and a cavity in the presence of multiple photons. Nonlinearity of the atomic response is needed to generate entanglement, but as that nonlinearity saturates the entanglement vanishes. We posit that this is due to spontaneous emission, which puts the atom in the ground state and the atom-field state into a direct product state. An intermediate value of the driving field, near the field that saturates the atomic response, optimizes the atom-field entanglement. In a parameter regime for which multiphoton resonances occur, we find that entanglement recurs at those resonances. In this regime, we find that the entanglement decreases with increasing photon number. We also investigate, in the bimodal regime, the entanglement as a function of atom and/or cavity detuning. Here we find that there is evidence of a phase transition in the entanglement, which occurs at 2 ɛ /g ≥1 .

  8. τ-MnAl with high coercivity and saturation magnetization

    Directory of Open Access Journals (Sweden)

    J. Z. Wei

    2014-12-01

    Full Text Available In this paper, high purity τ-Mn54Al46 and Mn54−xAl46Cxalloys were successfully prepared using conventional arc-melting, melt-spinning, and heat treatment process. The magnetic and the structural properties were examined using x-ray diffraction (XRD, powder neutron diffraction and magnetic measurements. A room temperature saturation magnetization of 650.5 kAm-1, coercivity of 0.5 T, and a maximum energy product of (BHmax = 24.7 kJm-3 were achieved for the pure Mn54Al46 powders without carbon doping. The carbon substituted Mn54−xAl46Cx, however, reveals a lower Curie temperature but similar saturation magnetization as compared to the carbon-free sample. The electronic structure of MnAl shows that the Mn atom possesses a magnetic moment of 2.454 μB which results from strong hybridization between Mn-Al and Mn-Mn. We also investigated the volume and c/a ratio dependence of the magnetic moments of Mn and Al. The results indicate that an increase in the intra-atomic exchange splitting due to the cell volume expansion, leads to a large magnetic moment for the Mn atom. The Mn magnetic moment can reach a value of 2.9 μB at a volume expansion rate of ΔV/V ≈ 20%.

  9. FLASH: A finite element computer code for variably saturated flow

    Energy Technology Data Exchange (ETDEWEB)

    Baca, R.G.; Magnuson, S.O.

    1992-05-01

    A numerical model was developed for use in performance assessment studies at the INEL. The numerical model, referred to as the FLASH computer code, is designed to simulate two-dimensional fluid flow in fractured-porous media. The code is specifically designed to model variably saturated flow in an arid site vadose zone and saturated flow in an unconfined aquifer. In addition, the code also has the capability to simulate heat conduction in the vadose zone. This report presents the following: description of the conceptual frame-work and mathematical theory; derivations of the finite element techniques and algorithms; computational examples that illustrate the capability of the code; and input instructions for the general use of the code. The FLASH computer code is aimed at providing environmental scientists at the INEL with a predictive tool for the subsurface water pathway. This numerical model is expected to be widely used in performance assessments for: (1) the Remedial Investigation/Feasibility Study process and (2) compliance studies required by the US Department of Energy Order 5820.2A.

  10. Reflectivity kinetics of saturable absorbers for laser mirrors

    Science.gov (United States)

    Rubtsova, N. N.; Borisov, G. M.; Gol'dort, V. G.; Kovalyov, A. A.; Ledovskikh, D. V.

    2016-02-01

    The reflectivity kinetics of saturable absorbers based on semiconductor quantum wells was investigated with differential reflectivity Δ \\text{R}/\\text{R}={{10}-5} accuracy by the pump-probe technique for energy fluxes (0.27-5.40)\\centerdot {{10}14} photons cm-2 using a femtosecond Yb3+ :KY(WO4)2 laser. Three kinds of saturable absorbers were investigated: absorbers based on multiple quantum wells with nano-structured barriers grown over a mirror; the same absorber grown over the substrate; absorbers on multiple quantum wells separated by thick barriers grown over the substrate. The substrate contribution gives a stationary background and a two-photon absorption peak for small probe delays, which complicates the kinetics of the samples grown over the substrate. For absorbers grown over the mirror two exponential decays with a short relaxation time {τ1}=0.2 -0.4 ps and with a long relaxation time {τ2}=7.8 ps were obtained. The last relaxation time is remarkably shorter than in quantum wells with thick barriers.

  11. SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-08-12

    We are now entering the final stages of our ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342). We have now developed several techniques to help distinguish economic hydrocarbon deposits from false ''Fizz'' gas signatures. These methods include using the proper in situ rock and fluid properties, evaluating interference effects on data, and doing better constrained inversions for saturations. We are testing these techniques now on seismic data from several locations in the Gulf of Mexico. In addition, we are examining the use of seismic attenuation as indicated by frequency shifts below potential reservoirs. During this quarter we have: Began our evaluation of our latest data set over the Neptune Field; Developed software for computing composite reflection coefficients; Designed and implemented stochastic turbidite reservoir models; Produced software & work flow to improve frequency-dependent AVO analysis; Developed improved AVO analysis for data with low signal-to-noise ratio; and Examined feasibility of detecting fizz gas using frequency attenuation. Our focus on technology transfer continues, both by generating numerous presentations for the upcoming SEG annual meeting, and by beginning our planning for our next DHI minisymposium next spring.

  12. Soil aquifer treatment of artificial wastewater under saturated conditions

    KAUST Repository

    Essandoh, H. M K

    2011-05-01

    A 2000 mm long saturated laboratory soil column was used to simulate soil aquifer treatment under saturated conditions to assess the removal of chemical and biochemical oxygen demand (COD and BOD), dissolved organic carbon (DOC), nitrogen and phosphate, using high strength artificial wastewater. The removal rates were determined under a combination of constant hydraulic loading rates (HLR) and variable COD concentrations as well as variable HLR under a constant COD. Within the range of COD concentrations considered (42 mg L-1-135 mg L-1) it was found that at fixed hydraulic loading rate, a decrease in the influent concentrations of dissolved organic carbon (DOC), biochemical oxygen demand (BOD), total nitrogen and phosphate improved their removal efficiencies. At the high COD concentrations applied residence times influenced the redox conditions in the soil column. Long residence times were detrimental to the removal process for COD, BOD and DOC as anoxic processes and sulphate reduction played an important role as electron acceptors. It was found that total COD mass loading within the range of 911 mg d-1-1780 mg d-1 applied as low COD wastewater infiltrated coupled with short residence times would provide better effluent quality than the same mass applied as a COD with higher concentration at long residence times. The opposite was true for organic nitrogen where relatively high concentrations coupled with long residence time gave better removal efficiency. © 2011.

  13. Practical remarks on the heart rate and saturation measurement methodology

    Science.gov (United States)

    Kowal, M.; Kubal, S.; Piotrowski, P.; Staniec, K.

    2017-05-01

    A surface reflection-based method for measuring heart rate and saturation has been introduced as one having a significant advantage over legacy methods in that it lends itself for use in special applications such as those where a person’s mobility is of prime importance (e.g. during a miner’s work) and excluding the use of traditional clips. Then, a complete ATmega1281-based microcontroller platform has been described for performing computational tasks of signal processing and wireless transmission. In the next section remarks have been provided regarding the basic signal processing rules beginning with raw voltage samples of converted optical signals, their acquisition, storage and smoothing. This chapter ends with practical remarks demonstrating an exponential dependence between the minimum measurable heart rate and the readout resolution at different sampling frequencies for different cases of averaging depth (in bits). The following section is devoted strictly to the heart rate and hemoglobin oxygenation (saturation) measurement with the use of the presented platform, referenced to measurements obtained with a stationary certified pulsoxymeter.

  14. Phosphorene quantum dot saturable absorbers for ultrafast fiber lasers

    Science.gov (United States)

    Du, J.; Zhang, M.; Guo, Z.; Chen, J.; Zhu, X.; Hu, G.; Peng, P.; Zheng, Z.; Zhang, H.

    2017-02-01

    We fabricate ultrasmall phosphorene quantum dots (PQDs) with an average size of 2.6 ± 0.9 nm using a liquid exfoliation method involving ultrasound probe sonication followed by bath sonication. By coupling the as-prepared PQDs with microfiber evanescent light field, the PQD-based saturable absorber (SA) device exhibits ultrafast nonlinear saturable absorption property, with an optical modulation depth of 8.1% at the telecommunication band. With the integration of the all-fiber PQD-based SA, a continuous-wave passively mode-locked erbium-doped (Er-doped) laser cavity delivers stable, self-starting pulses with a pulse duration of 0.88 ps and at the cavity repetition rate of 5.47 MHz. Our results contribute to the growing body of work studying the nonlinear optical properties of ultrasmall PQDs that present new opportunities of this two-dimensional (2D) nanomaterial for future ultrafast photonic technologies.

  15. Gluon saturation and Feynman scaling in leading neutron production

    Directory of Open Access Journals (Sweden)

    F. Carvalho

    2016-01-01

    Full Text Available In this paper we extend the color dipole formalism for the study of leading neutron production in e+p→e+n+X collisions at high energies and estimate the related observables which were measured at HERA and could be analyzed in future electron–proton (ep colliders. In particular, we calculate the Feynman xF distribution of leading neutrons, which is expressed in terms of the pion flux and the photon–pion total cross section. In the color dipole formalism, the photon–pion cross section is described in terms of the dipole–pion scattering amplitude, which contains information about the QCD dynamics at high energies and gluon saturation effects. We consider different models for the scattering amplitude, which have been used to describe the inclusive and diffractive ep HERA data. Moreover, the model dependence of our predictions with the description of the pion flux is analyzed in detail. We demonstrate the recently released H1 leading neutron spectra can be described using the color dipole formalism and that these spectra could help us to observe more clearly gluon saturation effects in future ep colliders.

  16. Lipotoxicity: Effects of Dietary Saturated and Transfatty Acids

    Directory of Open Access Journals (Sweden)

    Débora Estadella

    2013-01-01

    Full Text Available The ingestion of excessive amounts of saturated fatty acids (SFAs and transfatty acids (TFAs is considered to be a risk factor for cardiovascular diseases, insulin resistance, dyslipidemia, and obesity. The focus of this paper was to elucidate the influence of dietary SFA and TFA intake on the promotion of lipotoxicity to the liver and cardiovascular, endothelial, and gut microbiota systems, as well as on insulin resistance and endoplasmic reticulum stress. The saturated and transfatty acids favor a proinflammatory state leading to insulin resistance. These fatty acids can be involved in several inflammatory pathways, contributing to disease progression in chronic inflammation, autoimmunity, allergy, cancer, atherosclerosis, hypertension, and heart hypertrophy as well as other metabolic and degenerative diseases. As a consequence, lipotoxicity may occur in several target organs by direct effects, represented by inflammation pathways, and through indirect effects, including an important alteration in the gut microbiota associated with endotoxemia. Interactions between these pathways may perpetuate a feedback process that exacerbates an inflammatory state. The importance of lifestyle modification, including an improved diet, is recommended as a strategy for treatment of these diseases.

  17. Central venous oxygen saturation monitoring: role in adult donor care?

    Science.gov (United States)

    Powner, David J; Doshi, Pratik B

    2010-12-01

    Monitoring oxygen saturation of blood drawn from a catheter placed within the superior vena cava (Scvo2) has recently been promoted as a substitute for evaluating oxygen saturation of mixed venous blood drawn from the pulmonary artery (Svo2). The Svo2 reflects the balance between oxygen delivery and oxygen consumption throughout the body and, among critically ill patients, may be helpful for assessing resuscitation, cardiac function, or oxygen homeostasis end points. Use of Scvo2 instead has been promoted because of its easier access and recent use during resuscitation of patients with severe infections. Although data from healthy subjects and critically ill patients are available, no study has been done among organ donors to evaluate customary values for either Scvo2 or Svo2 or how well the values correspond. After loss of oxygen consumption in the brain following brain death, the customary values for these variables may be different from values in other groups of patients. Therefore, until donor-specific normative values for these important parameters are identified, we do not recommend that Scvo2 be used to evaluate the balance between donor oxygen consumption and delivery or as a variable to guide treatment.

  18. Thermohydraulic design of saturated temperature capsule for IASCC irradiation test

    Energy Technology Data Exchange (ETDEWEB)

    Ide, Hiroshi; Matsui, Yoshinori; Itabashi, Yukio [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment] [and others

    2002-10-01

    An advanced water chemistry controlled irradiation research device is being developed in JAERI, to perform irradiation tests for irradiation assisted stress corrosion cracking (IASCC) research concerned with aging of LWR. This device enables the irradiation tests under the water chemistry condition and the temperature, which simulate the conditions for BWR core internals. The advanced water chemistry controlled irradiation research device is composed of saturated temperature capsule inserted into the JMTR core and the water chemistry control unit installed in the reactor building. Regarding the saturated temperature capsule, the Thermohydraulic design of capsule structure was done, aimed at controlling the specimen's temperature, feeding water velocity on specimen's surface to the environment of BWR nearer. As the result of adopting the new capsule structure based on the design study, it was found out that feeding water velocity at the surface of specimen's is increased to about 10 times as much as before, and nuclear heat generated in the capsule components can be removed safely even in the abnormal event such as the case of loss of feeding water. (author)

  19. Pattern Analysis of Oxygen Saturation Variability in Healthy Individuals: Entropy of Pulse Oximetry Signals Carries Information about Mean Oxygen Saturation

    Directory of Open Access Journals (Sweden)

    Amar S. Bhogal

    2017-08-01

    Full Text Available Pulse oximetry is routinely used for monitoring patients' oxygen saturation levels with little regard to the variability of this physiological variable. There are few published studies on oxygen saturation variability (OSV, with none describing the variability and its pattern in a healthy adult population. The aim of this study was to characterize the pattern of OSV using several parameters; the regularity (sample entropy analysis, the self-similarity [detrended fluctuation analysis (DFA] and the complexity [multiscale entropy (MSE analysis]. Secondly, to determine if there were any changes that occur with age. The study population consisted of 36 individuals. The “young” population consisted of 20 individuals [Mean (±1 SD age = 21.0 (±1.36 years] and the “old” population consisted of 16 individuals [Mean (±1 SD age = 50.0 (±10.4 years]. Through DFA analysis, OSV was shown to exhibit fractal-like patterns. The sample entropy revealed the variability to be more regular than heart rate variability and respiratory rate variability. There was also a significant inverse correlation between mean oxygen saturation and sample entropy in healthy individuals. Additionally, the MSE analysis described a complex fluctuation pattern, which was reduced with age (p < 0.05. These findings suggest partial “uncoupling” of the cardio-respiratory control system that occurs with aging. Overall, this study has characterized OSV using pre-existing tools. We have showed that entropy analysis of pulse oximetry signals carries information about body oxygenation. This may have the potential to be used in clinical practice to detect differences in diseased patient subsets.

  20. Nitrogen saturation in humid tropical forests after 6 years of nitrogen and phosphorus addition

    DEFF Research Database (Denmark)

    Chen, Hao; Gurmesa, Geshere A.; Zhang, Wei

    2016-01-01

    Nitrogen (N) saturation hypothesis suggests that when an ecosystem reaches N-saturation, continued N input will cause increased N leaching, nitrous oxide (N2O) emission, and N mineralization and nitrification rates. It also suggests that a different element will become the main limiting......O emission rate and nitrate (NO3-) leaching rate were measured in an N-saturated old-growth tropical forest in southern China, after 6 years of N and P addition. We hypothesized that N addition would stimulate further N saturation, but P addition might alleviate N saturation. As expected, our...

  1. Nuclear Magnetic Resonance and Elastic Wave Velocity of Chalk Saturated with Brines Containing Divalent Ions

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    divided into groups of three and each group was saturated either with deionized water, calcite equilibrated water, or sodium chloride, magnesium chloride and calcium chloride solutions of the same ionic strength. Saturation with solutions that contain divalent ions caused major shifts in the distribution...... of the relaxation time. Core samples saturated with calcium chloride solution relaxed slower and those saturated with magnesium chloride solution relaxed faster than the rest of the samples. Along with the changes in relaxation the samples experienced smaller velocities of elastic waves when saturated with MgCl2...

  2. Design and optimization of pulsed Chemical Exchange Saturation Transfer MRI using a multiobjective genetic algorithm.

    Science.gov (United States)

    Yoshimaru, Eriko S; Randtke, Edward A; Pagel, Mark D; Cárdenas-Rodríguez, Julio

    2016-02-01

    Pulsed Chemical Exchange Saturation Transfer (CEST) MRI experimental parameters and RF saturation pulse shapes were optimized using a multiobjective genetic algorithm. The optimization was carried out for RF saturation duty cycles of 50% and 90%, and results were compared to continuous wave saturation and Gaussian waveform. In both simulation and phantom experiments, continuous wave saturation performed the best, followed by parameters and shapes optimized by the genetic algorithm and then followed by Gaussian waveform. We have successfully demonstrated that the genetic algorithm is able to optimize pulse CEST parameters and that the results are translatable to clinical scanners. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Improvement of water saturation shift referencing by sequence and analysis optimization to enhance chemical exchange saturation transfer imaging.

    Science.gov (United States)

    Müller-Lutz, Anja; Matuschke, Felix; Schleich, Christoph; Wickrath, Frithjof; Boos, Johannes; Schmitt, Benjamin; Wittsack, Hans-Jörg

    2016-07-01

    To optimize B0-field inhomogeneity correction for chemical exchange saturation transfer (CEST) imaging by investigating different water saturation shift referencing (WASSR) Z-spectrum shapes and different frequency correction techniques. WASSR Z-spectra were simulated for different B1-fields and pulse durations (PD). Two parameter settings were used for further simulations and experiments (WASSR1: B1=0.1 μT, PD=50ms; WASSR2: B1=0.3 μT, PD=40ms). Four frequency correction techniques were investigated: 1) MinW: Minimum of the spline-interpolated WASSR-spectrum; 2) MSCF: maximum symmetry center frequency algorithm; 3) PMSCF: further development of MSCF algorithm; 4) BFit: fit with Bloch equations. Performance of frequency correction was assessed with Monte-Carlo simulations and in-vivo MR examinations in the brain and intervertebral disks. Different shapes of WASSR-Z-spectra were obtained by changing B1 and PD including spectra with one (1-Peak) or two (2-Peak) minima. WASSR1 resulted in 1-Peak WASSR-spectrum, whereas WASSR2 resulted in 2-Peak WASSR-spectrum. Both Monte-Carlo simulations and in-vivo MR examinations revealed highest accuracy of field-inhomogeneity correction with WASSR1 combined with PMSCF or BFit. Using a WASSR sequence, which results in a Z-spectrum with a single absorption peak, in combination with advanced postprocessing algorithms enables improved B0-field inhomogeneity correction for CEST imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Dissolution of K-feldspar at CO2-saturated conditions

    Science.gov (United States)

    Rosenqvist, Jörgen; Kilpatrick, Andrew D.; Yardley, Bruce W. D.; Rochelle, Christopher A.

    2014-05-01

    Underground storage of carbon dioxide on a very large scale is widely considered to be an essential part of any strategy to reduce greenhouse gas emissions to the atmosphere. Aquifers in deep sedimentary basins have been identified as suitable targets for geological carbon dioxide storage, especially aquifers located in sandstone host rock. This has led to renewed interest in studying the interaction between sandstone minerals and aqueous fluids, as there is a paucity of data for CO2-containing systems at relevant conditions. In an attempt to improve data coverage for important silicate minerals, we have measured the dissolution kinetics of K-feldspar in CO2-saturated fluids over a range of temperatures. K-feldspar fragments were hand-picked from a larger sample, crushed to a narrow size range and cleaned. The grains were reacted with water in batch-type reactors at temperatures from 20°C to 200°C and pressures up to 200 bar, and the dissolution was followed by periodic withdrawal of aliquots of solution. The mineral grains were allowed to react with pure water for a number of weeks before injection of CO2 into the system. Excess CO2 was provided to ensure CO2 saturation in the experimental systems. While the reaction time before injection was not long enough to attain complete equilibrium, it did considerably lower the degree of undersaturation with respect to K-feldspar and helped highlight the effect of CO2 injection into a rock-equilibrated aqueous fluid. At all temperatures studied, injection of CO2 resulted in a rapid increase in the soluble concentrations of K and Si (and also Na from a plagioclase component). The dissolution then reached apparent steady state conditions after a few days, with observed dissolution rates in the range of 1E-9 to 1E-12 mol/m2/s over the temperature range studied. The CO2-saturated solutions maintained mildly acidic conditions throughout the experiments and the observed rates therefore fall roughly between rates measured in

  5. Experimental Bullard-von Karman dynamo: MHD saturated regimes

    Science.gov (United States)

    Miralles, Sophie; Plihon, Nicolas; Pinton, Jean-François

    2014-05-01

    The dynamo instability, converting kinetic energy into magnetic energy, creates the magnetic fields of many astrophysical bodies for which the flows are highly turbulent. Those turbulent fluctuations restricts the range of parameters of numerical and theoretical predictions. As laboratory experiments are closer from natural parameters, this approach is favored in this work. In the past decades, dynamo action has been observed in experiments involving laminar flows [1] or fully turbulent flows [2] in liquid sodium. Nevertheless, the saturation of the velocity field by the Lorentz force due to the dynamo magnetic field is weak in those experiment because the control parameter is always close to the threshold of the instability (which is not the case in astrophysical situations). The details of the mechanism of the back reaction of Lorentz force on the flow are not known. We present here an experimental semi-synthetic dynamo, for which a fluid turbulent induction mechanism ('omega' effect) is associated to an external amplification applying a current into a pair of coils. The flow, called von-Karman, is produced by the counter rotation of two coaxial propellers in a cylindrical tank filled with liquid gallium. The resulting flow is highly turbulent (Re > 10 ^ 5). The amplification, mimicking a turbulent 'alpha' effect, allow to observe the dynamo instability at low magnetic Reynolds number (Rm ~ 2), far below the threshold of natural homogeneous dynamo. This experiment reaches non linear regimes, for which the saturation is a MHD process, at control parameter several times the critical value. The instability grows through an on-off intermittent regime evolving into a full MHD saturated regime for which the Lorentz force is in balance with the inertial one. The power budget is strongly modified by the dynamo magnetic field and we give an insight of the estimated rate of conversion of kinetic energy into magnetic one from experimental data. Very rich regimes such as

  6. Simple Predictive Models for Saturated Hydraulic Conductivity of Technosands

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Razzaghi, Fatemeh; Møldrup, Per

    2012-01-01

    of technosands based on either (i) the classic Kozeny-Carman (K-C) model modified by considering the content of finer particles (fines) less than 200 microns to estimate an immobile water fraction or (ii) the Revil-Cathles (R-C) model modified by using the characteristic particle diameter from the Rosin......-Rammler particle size distribution (PSD) function. The Ks and PSD data of 14 golf course sands from literature as well as newly measured data for a size fraction of Lunar Regolith Simulant, packed at three different dry bulk densities, were used for model evaluation. The pore network tortuosity......Accurate estimation of saturated hydraulic conductivity (Ks) of technosands (gravel-free, coarse sands with negligible organic matter content) is important for irrigation and drainage management of athletic fields and golf courses. In this study, we developed two simple models for predicting Ks...

  7. Ethanol-induced lowering of arterial oxyhemoglobin saturation during hypoxia.

    Science.gov (United States)

    Hansen, J E; Claybaugh, J R

    1975-09-01

    Nine fasting, healthy, adult male volunteers were given oral carbohydrate before exposures to normoxia (PIO2 = 149 torr) and mild hypoxia (PIO2 = 98 torr). Following recovery, they were given oral ethanol before similar exposure to normoxia and mild hypoxia. Repeated measures of arterial blood and expired gases were made. Ethanol diminished respiratory gas exchange (R), causing lower alveolar and arterial oxygen pressures during normoxia and mild hypoxia and a reduction in arterial oxygen saturation from 89.9 to 87.4% during mild hypoxia. It is suggested that carbohydrates are preferable to ethanol and fats as nutrients during limited oxygen transport situations, such as high-altitude, carbon monoxide exposure, or during heavy exertion, and for patients with cardiovascular or pulmonary disease.

  8. No saturation in the accumulation of alien species worldwide

    Science.gov (United States)

    Seebens, Hanno; Blackburn, Tim M.; Dyer, Ellie E.; Genovesi, Piero; Hulme, Philip E.; Jeschke, Jonathan M.; Pagad, Shyama; Pyšek, Petr; Winter, Marten; Arianoutsou, Margarita; Bacher, Sven; Blasius, Bernd; Brundu, Giuseppe; Capinha, César; Celesti-Grapow, Laura; Dawson, Wayne; Dullinger, Stefan; Fuentes, Nicol; Jäger, Heinke; Kartesz, John; Kenis, Marc; Kreft, Holger; Kühn, Ingolf; Lenzner, Bernd; Liebhold, Andrew; Mosena, Alexander; Moser, Dietmar; Nishino, Misako; Pearman, David; Pergl, Jan; Rabitsch, Wolfgang; Rojas-Sandoval, Julissa; Roques, Alain; Rorke, Stephanie; Rossinelli, Silvia; Roy, Helen E.; Scalera, Riccardo; Schindler, Stefan; Štajerová, Kateřina; Tokarska-Guzik, Barbara; van Kleunen, Mark; Walker, Kevin; Weigelt, Patrick; Yamanaka, Takehiko; Essl, Franz

    2017-01-01

    Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970–2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization. PMID:28198420

  9. Macronutrient replacement options for saturated fat: effects on cardiovascular health.

    Science.gov (United States)

    Flock, Michael R; Fleming, Jennifer A; Kris-Etherton, Penny M

    2014-02-01

    The purpose of this review is to discuss macronutrient replacement options for saturated fatty acids (SFAs) to optimize cardiovascular disease (CVD) risk reduction. Dietary recommendations advise decreasing SFAs. There is convincing evidence that replacing SFAs with unsaturated fat, both omega-6 and omega-3 polyunsaturated fatty acids, reduces CVD risk. Monounsaturated fatty acid substitution for SFAs also decreases CVD risk. Replacing SFAs with refined carbohydrate does little to alter CVD risk, whereas whole-grain CHO or lean protein substitutions beneficially affect CVD risk. Modifying the macronutrient composition of the diet by replacing SFAs with unsaturated fatty acids, as well as lean protein and carbohydrate from whole grains, all lower CVD risk. Research is needed to identify food sources of macronutrients that optimize CVD risk reduction.

  10. An ESR Saturation Treatment for Solvated-Electron Systems

    Science.gov (United States)

    Hiromitsu, Ichiro; Hase, Hirotomo; Higashimura, Takenobu

    1985-06-01

    ESR saturation measurements of solvated electrons (esol-) in alkaline ices were carried out at 73 K and 4 K. When there was no cross-relaxation for esol-, the observed line widths of esol- did not agree with those calculated by Zhidkov’s treatment. The larger spin-packet width found at 73 K than that at 4 K was interpreted in terms of spectral diffusion. When cross-relaxation occurred between esol- and neighbouring radicals, the line widths of esol- were interpreted as being due to both the spectral diffusion and the cross-relaxation. A more comprehensive treatment including a cross-relaxation time is presented; this treatment succeeds in fitting the observed line widths to the theoretical ones.

  11. Advanced Takagi‒Sugeno fuzzy systems delay and saturation

    CERN Document Server

    Benzaouia, Abdellah

    2014-01-01

    This monograph puts the reader in touch with a decade’s worth of new developments in the field of fuzzy control specifically those of the popular Takagi-Sugeno (T-S) type. New techniques for stabilizing control analysis and design based on multiple Lyapunov functions and linear matrix inequalities (LMIs), are proposed. All the results are illustrated with numerical examples and figures and a rich bibliography is provided for further investigation. Control saturations are taken into account within the fuzzy model. The concept of positive invariance is used to obtain sufficient asymptotic stability conditions for the fuzzy system with constrained control inside a subset of the state space. The authors also consider the non-negativity of the states. This is of practical importance in many chemical, physical and biological processes that involve quantities that have intrinsically constant and non-negative sign: concentration of substances, level of liquids, etc. Results for linear systems are then extended to l...

  12. No saturation in the accumulation of alien species worldwide.

    Science.gov (United States)

    Seebens, Hanno; Blackburn, Tim M; Dyer, Ellie E; Genovesi, Piero; Hulme, Philip E; Jeschke, Jonathan M; Pagad, Shyama; Pyšek, Petr; Winter, Marten; Arianoutsou, Margarita; Bacher, Sven; Blasius, Bernd; Brundu, Giuseppe; Capinha, César; Celesti-Grapow, Laura; Dawson, Wayne; Dullinger, Stefan; Fuentes, Nicol; Jäger, Heinke; Kartesz, John; Kenis, Marc; Kreft, Holger; Kühn, Ingolf; Lenzner, Bernd; Liebhold, Andrew; Mosena, Alexander; Moser, Dietmar; Nishino, Misako; Pearman, David; Pergl, Jan; Rabitsch, Wolfgang; Rojas-Sandoval, Julissa; Roques, Alain; Rorke, Stephanie; Rossinelli, Silvia; Roy, Helen E; Scalera, Riccardo; Schindler, Stefan; Štajerová, Kateřina; Tokarska-Guzik, Barbara; van Kleunen, Mark; Walker, Kevin; Weigelt, Patrick; Yamanaka, Takehiko; Essl, Franz

    2017-02-15

    Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970-2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization.

  13. Quasilinear saturation of the aperiodic ordinary mode streaming instability

    Energy Technology Data Exchange (ETDEWEB)

    Stockem Novo, A., E-mail: anne@tp4.rub.de; Schlickeiser, R. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum-und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Yoon, P. H. [Institute for Physical Science & Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Lazar, M. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum-und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, 3001 Leuven (Belgium); Poedts, S. [Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, 3001 Leuven (Belgium); Seough, J. [Faculty of Human Development, University of Toyama, 3190, Gofuku, Toyama City, Toyama 930-8555 (Japan); International Research Fellow of the Japan Society for the Promotion of Science, Tokyo (Japan)

    2015-09-15

    In collisionless plasmas, only kinetic instabilities and fluctuations are effective in reducing the free energy and scatter plasma particles, preventing an increase of their anisotropy. Solar energetic outflows into the interplanetary plasma give rise to important thermal anisotropies and counterstreaming motions of plasma shells, and the resulting instabilities are expected to regulate the expansion of the solar wind. The present paper combines quasilinear theory and kinetic particle-in-cell simulations in order to study the weakly nonlinear saturation of the ordinary mode in hot counter-streaming plasmas with a temperature anisotropy as a follow-up of the paper by Seough et al. [Phys. Plasmas 22, 082122 (2015)]. This instability provides a plausible mechanism for the origin of dominating, two-dimensional spectrum of transverse magnetic fluctuations observed in the solar wind. Stimulated by the differential motion of electron counterstreams the O mode instability may convert their free large-scale energy by nonlinear collisionless dissipation on plasma particles.

  14. Structure in the nonlinear saturation spectrum of parametric instabilities.

    Science.gov (United States)

    Fejer, J. A.; Kuo, Y.-Y.

    1973-01-01

    The nonlinear saturation spectrum of the decay instability is obtained in the limit of small spontaneous emission, for comparable ion and electron temperatures, from numerical solutions of a kinetic equation based on an accurate expression for the nonlinearity. The spectral energy occupies several pairs of isolated saucer-shaped regions in wave-vector space. The regions increase in thickness, angular diameter, and number as the pump power is increased. The theory thus predicts the generation of waves propagating in directions which can differ substantially from the direction of the pump field. Ionospheric observations confirm this prediction; they were difficult to reconcile with the predictions of previous theories based on an approximated expression for the nonlinearity. The present work also corrects the results of previous one-dimensional theories that used an accurate expression for the nonlinearity and predicted 'spectral lines' in the limit of vanishing spontaneous emission.

  15. [Tissue oxygen saturation in the critically ill patient].

    Science.gov (United States)

    Gruartmoner, G; Mesquida, J; Baigorri, F

    2014-05-01

    Hemodynamic resuscitation seeks to correct global macrocirculatory parameters of pressure and flow. However, current evidence has shown that despite the normalization of these global parameters, microcirculatory and regional perfusion alterations can persist, and these alterations have been independently associated with a poorer patient prognosis. This in turn has lead to growing interest in new technologies for exploring regional circulation and microcirculation. Near infra-red spectroscopy allows us to monitor tissue oxygen saturation, and has been proposed as a noninvasive, continuous and easy-to-obtain measure of regional circulation. The present review aims to summarize the existing evidence on near infra-red spectroscopy and its potential clinical role in the resuscitation of critically ill patients in shock. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  16. Hot magnetized nuclear matter: Thermodynamic and saturation properties

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, Z. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Bordbar, G.H. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Center for Excellence in Astronomy and Astrophysics (CEAA-RIAAM)-Maragha, Maragha (Iran, Islamic Republic of)

    2017-03-15

    We have used a realistic nuclear potential, AV{sub 18}, and a many-body technique, the lowest-order constraint variational (LOCV) approach, to calculate the properties of hot magnetized nuclear matter. By investigating the free energy, spin polarization parameter, and symmetry energy, we have studied the temperature and magnetic field dependence of the saturation properties of magnetized nuclear matter. In addition, we have calculated the equation of state of magnetized nuclear matter at different temperatures and magnetic fields. It was found that the flashing temperature of nuclear matter decreases by increasing the magnetic field. In addition, we have studied the effect of the magnetic field on liquid gas phase transition of nuclear matter. The liquid gas coexistence curves, the order parameter of the liquid gas phase transition, and the properties of critical point at different magnetic fields have been calculated. (orig.)

  17. Twin laser cavity solitons in a VCSEL with saturable absorber

    Science.gov (United States)

    Eslami, Mansour; Kheradmand, Reza; Bahari, Parvin; Tajalli, Habib

    2015-09-01

    We show numerically the existence and stability of double-peak (twin) laser cavity solitons in a model of a semiconductor laser containing a saturable absorber. The onset of twin laser cavity solitons is observed in a narrow range of switching pulse energies above the maximum energy required to switch a normal single laser cavity soliton. Also, the FWHM value of the population dip at the end of injection is found to be wider which later breaks into two closely spaced dips. Three regimes of oscillating, oscillating-rotating and oscillating-rotating-travelling twin laser cavity solitons are reported depending on the value of a bifurcation parameter given by the ratio of the lifetimes of carriers in amplifier and absorber materials. The associated dynamical behaviors in these three regimes are also discussed.

  18. Standing torsional waves in a fully saturated, porous, circular cylinder

    CERN Document Server

    Solorza, S; 10.1111/j.1365-246X.2004.02198.x

    2004-01-01

    For dynamic measurement of the elastic moduli of a porous material saturated with viscous fluid using the resonance-bar technique, one also observes attenuation. In this article we have carried out the solution of the boundary-value problem associated with standing torsional oscillations of a finite, poroelastic, circular cylinder cast in the framework of volume-averaged theory of poroelasticity. Analysing this solution by eigenvalue perturbation approach we are able to develop expressions for torsional resonance and temporal attenuation frequencies in which the dependence upon the material properties are transparent. It shows how the attenuation is controlled by the permeability and the fluid properties, and how the resonance frequency drops over its value for the dry solid-frame due to the drag effect of fluid mass. Based upon this work we have a firm basis to determine solid-frame shear modulus, permeability, and tortuosity factor from torsional oscillation experiments.

  19. Non-Hermitian engineering of synthetic saturable absorbers

    CERN Document Server

    Teimourpour, M H; Srinivasan, K; El-Ganainy, R

    2016-01-01

    We introduce a new type of synthetic saturable absorbers based on quantum inspired photonic arrays whose linear light transport characteristics can be derived via bosonic algebra. We demonstrate that the interplay between optical Kerr nonlinearity, interference effects and non-Hermiticity through radiation loss leads to a nonlinear optical filtering response with two distinct regimes of small and large optical transmissions. More interestingly, we show that the boundary between these two regimes can be very sharp. The threshold optical intensity that marks this abrupt "phase transition" and its steepness can be engineered by varying the number of the guiding elements. The practical feasibility of these structures as well as their potential applications in laser systems and optical signal processing are also discussed.

  20. Saturated Zone Plumes in Volcanic Rock: Implications for Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    S. Kelkar; R. Roback; B. Robinson; G. Srinivasan; C. Jones; P. Reimus

    2006-02-14

    This paper presents a literature survey of the occurrences of radionuclide plumes in saturated, fractured rocks. Three sites, Idaho National laboratory, Hanford, and Oak Ridge are discussed in detail. Results of a modeling study are also presented showing that the length to width ratio of a plume starting within the repository footprint at the Yucca Mountain Project site, decreases from about 20:1 for the base case to about 4:1 for a higher value of transverse dispersivity, indicating enhanced lateral spreading of the plume. Due to the definition of regulatory requirements, this lateral spreading does not directly impact breakthrough curves at the 18 km compliance boundary, however it increases the potential that a plume will encounter reducing conditions, thus significantly retarding the transport of sorbing radionuclides.

  1. Ligand screening by saturation-transfer difference (STD) NMR spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, V V

    2005-04-26

    NMR based methods to screen for high-affinity ligands have become an indispensable tool for designing rationalized drugs, as these offer a combination of good experimental design of the screening process and data interpretation methods, which together provide unprecedented information on the complex nature of protein-ligand interactions. These methods rely on measuring direct changes in the spectral parameters, that are often simpler than the complex experimental procedures used to study structure and dynamics of proteins. The goal of this review article is to provide the basic details of NMR based ligand-screening methods, with particular focus on the saturation transfer difference (STD) experiment. In addition, we provide an overview of other NMR experimental methods and a practical guide on how to go about designing and implementing them.

  2. On the saturation amplitude of the f-mode instability

    CERN Document Server

    Kastaun, Wolfgang; Kokkotas, Kostas D

    2010-01-01

    We investigate strong nonlinear damping effects which occur during high amplitude oscillations of neutron stars, and the gravitational waves they produce. For this, we use a general relativistic nonlinear hydrodynamics code in conjunction with a fixed spacetime (Cowling approximation) and a polytropic equation of state (EOS). Gravitational waves are estimated using the quadrupole formula. Our main interest are $l=m=2$ $f$-modes subject to the CFS (Chandrasekhar, Friedman, Schutz) instability, but we also investigate axisymmetric and quasi-radial modes. We study various models to determine the influence of rotation rate and EOS. We find that axisymmetric oscillations at high amplitudes are predominantly damped by shock formation, while the non-axisymmetric $f$-modes are mainly damped by wave breaking and, for rapidly rotating models, coupling to non-axisymmetric inertial modes. From the observed nonlinear damping, we derive upper limits for the saturation amplitude of CFS-unstable $f$-modes. Finally, we estima...

  3. 3D myocardial T1 mapping using saturation recovery.

    Science.gov (United States)

    Nordio, Giovanna; Henningsson, Markus; Chiribiri, Amedeo; Villa, Adriana D M; Schneider, Torben; Botnar, René M

    2017-07-01

    To propose a 3D quantitative high-resolution T1 mapping technique, called 3D SASHA (saturation-recovery single-shot acquisition), which combines a saturation recovery pulse with 1D-navigator-based-respiratory motion compensation to acquire the whole volume of the heart in free breathing. The sequence was tested and validated both in a T1 phantom and in healthy subjects. The 3D SASHA method was implemented on a 1.5T scanner. A diaphragmatic navigator was used to allow free-breathing acquisition and the images were acquired with a resolution of 1.4 × 1.4 × 8 mm(3) . For assessment of accuracy and precision the sequence was compared with the reference gold-standard inversion-recovery spin echo (IRSE) pulse sequence in a T1 phantom, while for the in vivo studies (10 healthy volunteers) 3D SASHA was compared with the clinically used 2D MOLLI (3-3-5) and 2D SASHA protocols. There was good agreement between the T1 values measured in a T1 phantom with 3D SASHA and the reference IRSE pulse sequences (1111.6 ± 31 msec vs. 1123.6 ± 8 msec, P = 0.9947). Mean and standard deviation of the myocardial T1 values in healthy subjects measured with 2D MOLLI, 2D SASHA, and 3D SASHA sequences were 881 ± 40 msec, 1181.3 ± 32 msec, and 1153.6 ± 28 msec respectively. The proposed 3D SASHA sequence allows for high-resolution free-breathing whole-heart T1 -mapping with T1 values in good agreement with the 2D SASHA and improved precision. 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:218-227. © 2017 International Society for Magnetic Resonance in Medicine.

  4. Electronic paramagnetic resonance power saturation of wooden samples

    Science.gov (United States)

    Brai, Maria; Longo, Anna; Maccotta, Antonella; Marrale, Maurizio

    2009-05-01

    The deterioration of wood used for artifacts of artistic interest involves the production of different free radicals from the macromolecules of the wooden matrix (cellulose, lignin, and hemicellulose). Among the techniques able to provide information about these free radicals, the contribution of electronic paramagnetic resonance (EPR) can be very valuable. In this paper, the study of EPR signals (with g ≈2) of both modern and ancient wooden taxa was undertaken in order to analyze some features of the free radicals in natural wood. In particular, we have studied the microwave power saturation behaviors of seasoned wooden samples from ten species, and we have found remarkable differences between softwoods and hardwoods. These differences can be correlated to dissimilarities in the relaxation times T1 and T2 attributable to the different microscopic structures of the two trees' categories. The method has been also applied to ancient woods belonging to works of art in order to assess the conservation state of these artifacts. The analysis of the saturation curves has been found to be sensitive to the wood decay state. Indeed the deterioration process of the wooden matrix involves a variation of the relaxation times; this could be ascribed to both possible structure modifications and to concentration increments of the free radicals inside ancient woods due to decay induced by natural (biological, chemical, and physical) agents. This analysis method seems to be promising for the characterization of the wooden decay state and, therefore, it could provide valuable diagnostic indications which are necessary for the restoration and conservation of many artifact of historical-artistic-archaeological interest.

  5. Coding Techniques to Reduce Material Saturation in Holographic Data Storage

    Science.gov (United States)

    Phillips, Seth William

    Holographic data storage (HDS) is an emerging data storage technology that has received attention due to a high theoretical data capacity, fast readout times, and a potentially long lifetime of the recording materials. The work presented in this thesis was undertaken to solve one of the technical impediments preventing the widespread use of HDS, the occurrence of large concentrations of power in recorded holograms. Such peak values of optical power cause the medium to saturate during the recording process. As a result, the most significant portions of the hologram are not recorded accurately, and on readout, saturated recordings are not reconstructed correctly. In the implementation of HDS considered in this thesis, data is organized into an array of pixels using hybrid ternary modulation that contains an OFF-pixel and two different ON-pixels that are differentiated by their phase terms. The Fourier transform of this data array is created optically and the image of the Fourier transform is recorded holographically. This thesis presents a two-step coding technique that decreases the likelihood and severity of peaks in encoded holograms. In the first step, sparsity, the proportion of OFF-pixels in the array, is increased, which decreases the total power in the encoded array. In the second step, phase masks are used to alter the phase of ON-pixels to decrease periodic content in the data array. This reduces the likelihood of an encoded array containing large peak values at any point in the Fourier domain. Analysis is presented for the sparsity encoding which demonstrates the worst-case sparsity for certain system parameters. The performance of both the sparsity encoding and phase masking procedure are tested with numerical simulations. The results of these simulations indicate that these encoding techniques effectively inhibit the occurrence of large intensity peaks the holograms of encoded arrays.

  6. Novel Superdielectric Materials: Aqueous Salt Solution Saturated Fabric

    Directory of Open Access Journals (Sweden)

    Jonathan Phillips

    2016-11-01

    Full Text Available The dielectric constants of nylon fabrics saturated with aqueous NaCl solutions, Fabric-Superdielectric Materials (F-SDM, were measured to be >105 even at the shortest discharge times (>0.001 s for which reliable data could be obtained using the constant current method, thus demonstrating the existence of a third class of SDM. Hence, the present results support the general theoretical SDM hypothesis, which is also supported by earlier experimental work with powder and anodized foil matrices: Any material composed of liquid containing dissolved, mobile ions, confined in an electrically insulating matrix, will have a very high dielectric constant. Five capacitors, each composed of a different number of layers of salt solution saturated nylon fabric, were studied, using a galvanostat operated in constant current mode. Capacitance, dielectric constant, energy density and power density as a function of discharge time, for discharge times from ~100 s to nearly 0.001 s were recorded. The roll-off rate of the first three parameters was found to be nearly identical for all five capacitors tested. The power density increased in all cases with decreasing discharge time, but again the observed frequency response was nearly identical for all five capacitors. Operational limitations found for F-SDM are the same as those for other aqueous solution SDM, particularly a low maximum operating voltage (~2.3 V, and dielectric “constants” that are a function of voltage, decreasing for voltages higher than ~0.8 V. Extrapolations of the present data set suggest F-SDM could be the key to inexpensive, high energy density (>75 J/cm3 capacitors.

  7. SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-01-22

    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  8. Seismic Evaluation of Hydorcarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-10-31

    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  9. Relationship between saturated fatty acids and periodontal disease.

    Science.gov (United States)

    Iwasaki, M; Manz, M C; Moynihan, P; Yoshihara, A; Muramatsu, K; Watanabe, R; Miyazaki, H

    2011-07-01

    Saturated fatty acids (SFAs) produce an inflammatory response. Hyperinflammation is now recognized as one of the key underlying etiologic factors in periodontal disease. The longitudinal relationship between dietary SFAs and periodontal disease in 264 Japanese individuals, aged 75 years, for whom data were available for the years 2003-2004, was investigated. SFA intake was assessed with a brief self-administered diet history questionnaire. Participants were classified by quartiles of SFA intake. Full-mouth periodontal status, measured as the clinical attachment level (CAL), was recorded at baseline and follow-up examinations. The number of teeth with a loss of CAL≥3 mm at any site over a year was calculated as 'periodontal disease events'. Poisson regression analysis was conducted, with dietary SFAs as the primary predictor of interest, to estimate their influence on periodontal disease events. High dietary SFA intake was significantly associated with a greater number of periodontal disease events among non-smokers. The multivariate adjusted relative risk (95% confidence intervals) in the 1st, 2nd, 3rd, and 4th quartiles of dietary SFAs was 1.00, 1.19 (0.72-1.97), 1.55 (0.95-2.52), and 1.92 (1.19-3.11), respectively. These findings suggest an independent association of dietary SFA intake to the progression of periodontal disease in older Japanese non-smokers. saturated fatty acid (SFA); clinical attachment level (CAL); Toll-like receptor (TLR); lipopolysaccharide (LPS); brief self-administered diet history questionnaire (BDHQ); decayed, missing, and filled teeth (DMFT); clinical attachment level (CAL); body mass index (BMI); relative risk (RR); confidence intervals (CI); nuclear factor-kappa B (NF-κB).

  10. Unsaturated Zone and Saturated Zone Transport Properties (U0100)

    Energy Technology Data Exchange (ETDEWEB)

    J. Conca

    2000-12-20

    This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion.

  11. Characterizing saturated mass transport in fractured cementitious materials

    Science.gov (United States)

    Akhavan, Alireza

    Concrete, when designed and constructed properly, is a durable material. However in aggressive environments concrete is prone to gradual deterioration which is due to penetration of water and aggressive agents (e.g., chloride ions) into concrete. As such, the rate of mass transport is the primary factor, controlling the durability of cementitious materials. Some level of cracking is inevitable in concrete due to brittle nature of the material. While mass transport can occur through concrete’s porous matrix, cracks can significantly accelerate the rate of mass transport and effectively influence the service life of concrete structures. To allow concrete service life prediction models to correctly account for the effect of cracks on concrete durability, mass transport thru cracks must be characterized. In this study, transport properties of cracks are measured to quantify the saturated hydraulic permeability and diffusion coefficient of cracks as a function of crack geometry (i.e.; crack width, crack tortuosity and crack wall roughness). Saturated permeability and diffusion coefficient of cracks are measured by constant head permeability test, electrical migration test, and electrical impedance spectroscopy. Plain and fiber reinforced cement paste and mortar as well as simulated crack samples are tested. The results of permeability test showed that the permeability of a crack is a function of crack width squared and can be predicted using Louis formula when crack tortuosity and surface roughness of the crack walls are accounted for. The results of the migration and impedance tests showed that the diffusion coefficient of the crack is not dependent on the crack width, but is primarily a function of volume fraction of cracks. The only parameter that is changing with the crack width is the crack connectivity. Crack connectivity was found to be linearly dependent on crack width for small crack and constant for large cracks (i.e.; approximately larger than 80 µm). The

  12. Mechanical behavior of saturated, consolidated, alumina powder compacts

    Science.gov (United States)

    Franks, George Vincent, Jr.

    Alumina slurries were prepared with three differing particle pair potentials produced by adjusting pH and salt concentration. The three pair potentials investigated were repulsive, strongly attractive and weakly attractive. Bodies were consolidated by pressure filtration, at applied pressures between 0.25 MPa and 150 MPa. The mechanical properties of these bodies were investigated by uniaxial compressive loading. High consolidation pressures lead to high forces at particle contacts which can push the particles together to form a strong touching network even when the particles are separated by a potential barrier in the slurry state. When particles are pushed into adhesive contact, the saturated, consolidated powder compacts are brittle. When a short ranged repulsive interparticle potential persists after consolidation, the specimens are plastic. Saturated bodies formed from strongly attractive slurries (flocculated at the isoelectric point pH 9) were plastic at low relative densities but were brittle at higher relative densities. Bodies formed from the repulsive slurries (dispersed at pH 4) were always brittle. Bodies consolidated from weakly attractive slurries (coagulated at pH 4, 5, 6, or 12 with additions of salt) were plastic at low consolidation pressures but became brittle at high consolidation pressures. This plastic-to-brittle transition depends on the shape of the pair potential, the size and morphology of the powder. The plastic specimens had stress-strain behavior characterized by a peak stress, followed by a lower flow stress. The peak stress reduced to the flow stress upon several reloading cycles. The effect of the slope of the repulsive potential barrier on the plastic-to-brittle transition was investigated. Alumina slurries coagulated at pH 12 with 0.5 M of Lisp+, Cssp+ and tetraethylammoniumsp+ chlorides were consolidated by pressure filtration. Consolidation pressures required to push particles together were greater for smaller counterions. The

  13. Predicting saturated hydraulic conductivity using soil morphological properties

    Directory of Open Access Journals (Sweden)

    Gülay Karahan

    2016-01-01

    Full Text Available Many studies have been conducted to predict soil saturated hydraulic conductivity (Ks by parametric soil properties such as bulk density and particle-size distribution. Although soil morphological properties have a strong effect on Ks, studies predicting Ks by soil morphological properties such as type, size, and strength of soil structure; type, orientation and quantity of soil pores and roots and consistency are rare. This study aimed at evaluating soil morphological properties to predict Ks. Undisturbed soil samples (15 cm length and 8.0 cm id. were collected from topsoil (0-15 cm and subsoil (15-30 cm (120 samples with a tractor operated soil sampler at sixty randomly selected sampling sites on a paddy field and an adjecent grassland in Central Anatolia (Cankırı, Turkey. Synchronized disturbed soil samples were taken from the same sampling sites and sampling depths for basic soil analyses. Saturated hydraulic conductivity was measured on the soil columns using a constant-head permeameter. Following the Ks measurements, the upper part of soil columns were covered to prevent evaporation and colums were left to drain in the laboratory. When the water flow through the column was stopped, a subsample were taken for bulk density and then soil columns were disturbed for describing the soil morphological properties. In addition, soil texture, bulk density, pH, field capacity, wilting point, cation exchange capacity, specific surface area, aggregate stability, organic matter, and calcium carbonate were measured on the synchronized disturbed soil samples. The data were divided into training (80 data values and validation (40 data values sets. Measured values of Ks ranged from 0.0036 to 2.14 cmh-1 with a mean of 0.86 cmh-1. The Ks was predicted from the soil morphological and parametric properties by stepwise multiple linear regression analysis. Soil structure class, stickiness, pore-size, root-size, and pore-quantity contributed to the Ks prediction

  14. Cerebral regional oxygen saturation monitoring in pediatric malfunctioning shunt patients.

    Science.gov (United States)

    Abramo, Thomas J; Zhou, Chuan; Estrada, Cristina; Drayna, Patrick C; Locklair, Matthew R; Miller, Renee; Pearson, Matthew; Tulipan, Noel; Arnold, Donald H

    2013-02-01

    Shunt malfunction produces increased intracranial pressure causing decreased cerebral regional perfusion and tissue O(2)sat. Cerebral regional oxygen saturation (rSO(2)) by near-infrared spectroscopy represents tissue perfusion and oxygen saturation. Cerebral rSO(2) is used to detect cerebral ischemia in pediatric clinical settings. The objective of the study was to determine the reliability of cerebral rSO(2) in pediatric malfunctioning shunt. A prospective observational study of pediatric patients presented to the pediatric emergency department was conducted. Confirmed malfunctioning shunt subjects had cerebral rSO(2) monitoring. A total of 131 malfunctioning shunt subjects had cerebral rSO(2) monitoring. Patient's central trend and intrasubject variability of cerebral rSO(2) readings for left and right probe and malfunction sites (n = 131) are as follows: Intrasubject left and right rSO(2) Pearson correlation was -0.46 to 0.98 (mean ± SD, 0.35 ± 0.34; median, 0.34; interquartile range, 0.06-0.61). The correlation coefficients of 99 subjects between left and right rSO(2) was significantly different (P < .001), suggesting that intrasubjects' left and right rSO(2) are highly correlated. Sample mean difference between left and right rSO(2) were -1.7% (95% confidence interval [CI], -1.8 to -1.6; P < .001) supporting overall left lower than right. Intraclass correlation for left rSO(2) was 87.4% (95% CI, 87.2%-87.6%), and that for right rSO(2) was 83.8% (95% CI, 83.8%-84%), showing intersubject differences accounting for the variation, and relative to intersubject variation, intrasubjects readings are consistent. Intrasubjects, left and right rSO(2) highly correlate and are asymmetrical. Left and right rSO(2) are consistent in intrasubject with large rSO(2) variations in trend and variability across subjects. This study demonstrates reliable cerebral rSO(2) readings in subjects with malfunctioning shunts, with asymmetrical cerebral rSO(2) hemispheric dynamics within

  15. Adaptive control of systems in cascade with saturation

    Science.gov (United States)

    Kannan, Suresh K.

    This thesis extends the use of neural-network-based model reference adaptive control to systems that occur as cascades. In general, these systems are not feedback linearizable. The approach taken is that of approximate feedback linearization of upper subsystems whilst treating the lower-subsystem states as virtual actuators. Similarly, lower-subsystems are also feedback linearized. Typically, approximate inverses are used for linearization purposes. Model error arising from the use of an approximate inverse is minimized using a neural-network as an adaptive element. Incorrect adaptation due to (virtual) actuator saturation and dynamics is avoided using the Pseudocontrol Hedging method. Using linear approximate inverses and linear reference models generally result in large desired pseudocontrol for large external commands. Even if the provided external command is feasible (null-controllable), there is no guarantee that the reference model trajectory is feasible. In order to mitigate this, nonlinear reference models based on nested-saturation methods are used to constrain the evolution of the reference model and thus the plant states. The method presented in this thesis lends itself to the inner-outer loop control of air vehicles, where the inner-loop controls attitude dynamics and the outer-loop controls the translational dynamics of the vehicle. The outer-loop treats the closed loop attitude dynamics as an actuator. Adaptation to uncertainty in the attitude, as well as the translational dynamics, is introduced, thus minimizing the effects of model error in all six degrees of freedom and leading to more accurate position tracking. A pole-placement approach is used to choose compensator gains for the tracking error dynamics. This alleviates timescale separation requirements, allowing the outer loop bandwidth to be closer to that of the inner loop, thus increasing position tracking performance. A poor model of the attitude dynamics and a basic kinematics model is

  16. Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2006-01-30

    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), our efforts have become focused on technology transfer. To this end, we completing our theoretical developments, generating recommended processing flows, and perfecting our rock and fluid properties interpretation techniques. Some minor additional data analysis and modeling will complete our case studies. During this quarter we have: Presented findings for the year at the DHI/FLUIDS meeting at UH in Houston; Presented and published eight papers to promote technology transfer; Shown how Rock and fluid properties are systematic and can be predicted; Shown Correct values must be used to properly calibrate deep-water seismic data; Quantified and examined the influence of deep water geometries in outcrop; Compared and evaluated hydrocarbon indicators for fluid sensitivity; Identified and documented inappropriate processing procedures; Developed inversion techniques to better distinguish hydrocarbons; Developed new processing work flows for frequency-dependent anomalies; and Evaluated and applied the effects of attenuation as an indicator. We have demonstrated that with careful calibration, direct hydrocarbon indicators can better distinguish between uneconomic ''Fizz'' gas and economic hydrocarbon reservoirs. Some of this progress comes from better characterization of fluid and rock properties. Other aspects include alternative techniques to invert surface seismic data for fluid types and saturations. We have also developed improved work flows for accurately measuring frequency dependent changes in seismic data that are predicted by seismic models, procedures that will help to more reliably identify anomalies associated with hydrocarbons. We have been prolific in publishing expanded abstracts and presenting results, particularly at the SEG. This year, we had eight such

  17. Conceptual design of safety injection tanks using saturated water

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae Min; Jeong, Yong Hoon; Chang, Won Joon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2009-07-01

    Safety Injection Tanks (SITs) which is the one of Safety Injection System (SIS) play an important role in mitigating the Loss of Coolant Accidents (LOCAs) in Pressurized Water Reactor (PWR). APR1400 has the advanced 4 SITs directly connected to a reactor vessel. We expect the capacity of the SITs is getting more important since the coolant from SITs equipped with a FD during LBLOCA can replace the injection from low pressure safety injection pumps (LPSIPs). In designing a larger capacity SIT, we may have three problems; the excessively large volume for pressurized N{sub 2} gas, which is about 1/3 of the total volume, the difficulties controlling injection flowrate and the solubility of the non-condensable N{sub 2} gas in the coolant. In here, there is the contradiction which is 'there must be nitrogen gas for pressurization but there must not be nitrogen gas for more coolant.' For this problem, the axiomatic design (AD) theory enabled us to define or regularize the intrinsic problem which is termed the coupling and the contradiction. TRIZ facilitates creating solutions on the contradiction. This study proposes a conceptual design of SITs which are pressurized by steam from the saturated water as a demonstration of the conceptual design framework, AD theory and TRIZ. The purpose of this conceptual design is to increase coolant volume and to reduce N{sub 2} gas volume in SITs. In order to investigate the feasibility of the proposed design, we derived an analytical model to find the heat loss of saturated water and thermo-hydraulic safety analysis using MARS3.1. To confirm the safety and integrity of core, we conducted LBLOCA simulation to find peak cladding temperature (PCT) of design using the proposed SITs comparing with the conventional SITs. From the analysis results, the benefits of the new SIT design were observed in terms of the PCT, the quenching time and the size. And the new SIT design may enable emergency core cooling water to be injected

  18. Retinal oxygen saturation in relation to retinal thickness in diabetic macular edema

    DEFF Research Database (Denmark)

    Blindbæk, Søren Leer; Peto, Tunde; Grauslund, Jakob

    with DME had higher retinal oxygen saturation in macular venules as compared to the global retinal venous oxygen saturation. No correlation was demonstrated between retinal thickness and retinal oxygen saturation. Retinal oximetry may become an important clinical tool to monitor disease activity...... to retinal thickness in patients with diabetic macular edema (DME). Methods: We included 18 patients with DME that all had central retinal thickness (CRT) >300 µm and were free of active proliferative diabetic retinopathy. Optical coherence tomography (Topcon 3D OCT-2000 spectral domain OCT) was used.......4 and 3.8 years. Median HbA1c was 61.5 mmol/mol and 22.2% were women. Mean oxygen saturation was higher in retinal macular venules as compared to global venous oxygen saturation (76.7% vs. 66.3%, p=0.0001), whereas there was no difference between macular and global arteriolar oxygen saturations (94.8% vs...

  19. Measurement of retinal oxygen saturation in patients with chronic obstructive pulmonary disease.

    Science.gov (United States)

    Palkovits, Stefan; Lasta, Michael; Boltz, Agnes; Schmidl, Doreen; Kaya, Semira; Hammer, Martin; Marzluf, Beatrice; Popa-Cherecheanu, Alina; Frantal, Sophie; Schmetterer, Leopold; Garhöfer, Gerhard

    2013-02-05

    There is growing evidence that disturbances in retinal oxygenation may trigger ocular diseases. New instruments allow for the noninvasive measurement of retinal oxygen saturation in humans. The present study was designed to investigate the retinal oxygen saturation in patients with chronic obstructive pulmonary disease (COPD). This was also done in an effort to test the validity of retinal oxygenation measurements with a retinal vessel analyzer. In all, 16 patients with severe COPD grade 4 who were on long-term oxygen treatment were included in the study. For each patient two identical study days were scheduled. Measurements of retinal arterial and venous oxygen saturation were done using a commercially available instrument for retinal oxygen analysis. Peripheral arterial oxygen saturation values were analyzed with pulse oximetry and via a capillary blood sample drawn from the earlobe. Measurements were performed during oxygen treatment and during a period without oxygen supplementation. Analysis of all images for retinal oxygen saturation quantification was done by a masked investigator. Analysis was done using Pearson's correlation and a multivariate regression model. Arterial and venous retinal oxygen saturation decreased significantly after the cessation of the oxygen therapy. The arteriovenous oxygen difference was unchanged while breathing ambient air or pure oxygen-enriched air. With both Pearson's correlation and the multivariate model, we found significant positive correlation coefficients between retinal arterial and peripheral arterial oxygen saturation as assessed with pulse oximetry as well as between retinal arterial and peripheral arterial oxygen saturation measured in blood samples. The change of oxygen saturation after discontinuation of oxygen supplementation showed a good correlation between retinal arterial oxygen saturation and peripheral arterial oxygen saturation (r = 0.53, P arterial and peripheral arterial oxygen saturation indicating good

  20. Inferring immobile and in-situ water saturation from laboratory and field measurements

    Energy Technology Data Exchange (ETDEWEB)

    Belen, Rodolfo P., Jr.

    2000-06-01

    Analysis of experimental data and numerical simulation results of dynamic boiling experiments revealed that there is an apparent correlation between the immobile water saturation and the shape of the steam saturation profile. An elbow in the steam saturation profile indicates the sudden drop in steam saturation that marks the transition from steam to two-phase conditions inside the core during boiling. The immobile water saturation can be inferred from this elbow in the steam saturation profile. Based on experimental results obtained by Satik (1997), the inferred immobile water saturation of Berea sandstone was found to be about 0.25, which is consistent with results of relative permeability experiments reported by Mahiya (1999). However, this technique may not be useful in inferring the immobile water saturation of less permeable geothermal rocks because the elbow in the steam saturation profile is less prominent. Models of vapor and liquid-dominated geothermal reservoirs that were developed based on Darcy's law and material and energy conservation equations proved to be useful in inferring the in-situ and immobile water saturations from field measurements of cumulative mass production, discharge enthalpy, and downhole temperature. Knowing rock and fluid properties, and the difference between the stable initial, T{sub o}, and dry-out, T{sub d}, downhole temperatures, the in-situ and immobile water saturations of vapor-dominated reservoirs can be estimated. On the other hand, the in-situ and immobile water saturations, and the change in mobile water content of liquid-dominated reservoirs can be inferred from the cumulative mass production, {Delta}m, and enthalpy, h{prime}, data. Comparison with two-phase, radial flow, numerical simulation results confirmed the validity and usefulness of these models.

  1. RECIFE-SAT: A MILP-based algorithm for the railway saturation problem

    OpenAIRE

    PELLEGRINI, Paola; MARLIERE, Grégory; RODRIGUEZ, Joaquin

    2017-01-01

    Measuring capacity of railway infrastructures is a problem even in its definition. In this paper, we propose RECIFE-SAT, a MILP-based algorithm to quantify capacity by solving the saturation problem. This problem consists of saturating an infrastructure by adding as many trains as possible to an existing (possibly empty) timetable. Specifically, RECIFE-SAT considers a large set of potentially interesting saturation trains and integrates them in the timetable whenever possible. This integratio...

  2. Methods of integral saturation elimination in automatic regulation systems with PID-controllers

    Directory of Open Access Journals (Sweden)

    Дмитро Олегович Кроніковський

    2014-11-01

    Full Text Available The effect of integral saturation that reduces the quality of regulation appears with classic PID-controller usage in the real conditions.The pulp dryer of sugar factory as the real object of automation is considered. The impact of integral saturation is demonstrated based on the control processes modeling in pulp dryer. A modern methods to eliminate the integral saturation are considered. 

  3. A Single Image Dehazing Method Using Average Saturation Prior

    Directory of Open Access Journals (Sweden)

    Zhenfei Gu

    2017-01-01

    Full Text Available Outdoor images captured in bad weather are prone to yield poor visibility, which is a fatal problem for most computer vision applications. The majority of existing dehazing methods rely on an atmospheric scattering model and therefore share a common limitation; that is, the model is only valid when the atmosphere is homogeneous. In this paper, we propose an improved atmospheric scattering model to overcome this inherent limitation. By adopting the proposed model, a corresponding dehazing method is also presented. In this method, we first create a haze density distribution map of a hazy image, which enables us to segment the hazy image into scenes according to the haze density similarity. Then, in order to improve the atmospheric light estimation accuracy, we define an effective weight assignment function to locate a candidate scene based on the scene segmentation results and therefore avoid most potential errors. Next, we propose a simple but powerful prior named the average saturation prior (ASP, which is a statistic of extensive high-definition outdoor images. Using this prior combined with the improved atmospheric scattering model, we can directly estimate the scene atmospheric scattering coefficient and restore the scene albedo. The experimental results verify that our model is physically valid, and the proposed method outperforms several state-of-the-art single image dehazing methods in terms of both robustness and effectiveness.

  4. Physical extraction of microorganisms from water-saturated, packed sediment.

    Science.gov (United States)

    Ugolini, Fabio; Schroth, Martin H; Bürgmann, Helmut; Zeyer, Josef

    2014-05-01

    Microbial characterization of aquifers should include samples of both suspended and attached microorganisms (biofilms). We investigated the effect of shear, sonication, and heat on the extraction of microorganisms from water-saturated, packed sediment columns containing established biofilms. Shear was studied by increasing flow velocity of the column eluent, sonication by treating the columns with ultrasound at different power levels, and heat by warming up the column eluent to different temperatures. Effluent cell concentrations were used as a measure of extraction efficiency. Dissolved organic carbon and adenosine tri-phosphate (ATP) concentrations were used to corroborate cell-extraction results. Additionally, ATP was used as an indicator of cell-membrane integrity. Extraction quality was determined by comparing terminal-restriction fragment length polymorphism (T-RFLP) profiles of extracted bacterial communities with destructively sampled sediment-community profiles. Sonication and heat increased the extraction efficiency up to 200-fold and yielded communities comparable to the sediment community. These treatments showed high potential for in-situ application in aquifers.

  5. Nanographene-Based Saturable Absorbers for Ultrafast Fiber Lasers

    Directory of Open Access Journals (Sweden)

    Hsin-Hui Kuo

    2014-01-01

    Full Text Available The generation of femtosecond pulse laser in the erbium-doped fiber laser system is presented by integrating of the nanographene-based saturable absorbers (SAs. A simplified method of dispersed nanographene-based SAs side-polished fiber device with controllable polished length and depth was also developed. The dependence of geometry of a graphene-deposited side-polished fiber device on optical nonlinear characteristics and on the performance of the MLFL was screened. We found that the 10 mm polished length with 1.68 dB insertion loss had the highest modulation depth (MD of 1.2%. A stable MLFL with graphene-based SAs employing the optimized side-polished fiber device showed a pulse width, a 3 dB bandwidth, a time-bandwidth product (TBP, a repetition rate, and pulse energy of 523 fs, 5.4 nm, 0.347, 16.7 MHz, and 0.18 nJ, respectively, at fundamental soliton-like operation. The femtosecond pulse laser is achieved by evanescent field coupling through graphene-deposited side-polished fiber devices in the laser cavity. This study demonstrates that the polished depth is the key fabrication geometric parameter affecting the overall optical performance and better results exist within the certain polished range.

  6. Strong saturable absorption of black titanium oxide nanoparticle films

    Science.gov (United States)

    Zhang, Rong-Fang; Guo, Deng-Zhu; Zhang, Geng-Min

    2017-12-01

    Nonlinear optical materials with strong saturable absorption (SA) properties play an essential role in passive mode-locking generation of ultrafast lasers. Here we report black TiO2-x nanoparticles are promising candidate for such an application. Black TiO2-x nanoparticles are synthesized by using cathodic plasma electrolysis, and nanoparticle films are deposited on optical glass plates via natural sedimentation and post annealing. Characterization of the samples with TEM, SEM, XRD and XPS reveal that nanoparticles have diameters of 8-70 nm, and are in polycrystalline structure and co-existence of anatase, rutile and abundant oxygen-deficient phases. Optical transmittance and reflectance measurements with a UV/VIS/NIR spectrophotometer evidence an excellent wide-spectral optical absorption property. The nonlinear optical properties of the samples were measured by using open-aperture Z-scan technique with picosecond 532-nm laser, and verified by direct transmission measurements using nanosecond 1064-nm laser. Strong SA behavior was detected, and the nonlinear absorption coefficient is as high as β = - 4.9 × 10-8 m/W, at least two orders larger than most previous reports on ordinary TiO2. The strong SA behaviors are ascribed to the existence of plenty surface states and defect states within bandgap, and the relaxation rates of electrons from upper energy levels to lower ones are much slower than excitation rates.

  7. Coral calcifying fluid aragonite saturation states derived from Raman spectroscopy

    Science.gov (United States)

    DeCarlo, Thomas M.; D'Olivo, Juan P.; Foster, Taryn; Holcomb, Michael; Becker, Thomas; McCulloch, Malcolm T.

    2017-11-01

    Quantifying the saturation state of aragonite (ΩAr) within the calcifying fluid of corals is critical for understanding their biomineralization process and sensitivity to environmental changes including ocean acidification. Recent advances in microscopy, microprobes, and isotope geochemistry enable the determination of calcifying fluid pH and [CO32-], but direct quantification of ΩAr (where ΩAr = [CO32-][Ca2+]/Ksp) has proved elusive. Here we test a new technique for deriving ΩAr based on Raman spectroscopy. First, we analysed abiogenic aragonite crystals precipitated under a range of ΩAr from 10 to 34, and we found a strong dependence of Raman peak width on ΩAr with no significant effects of other factors including pH, Mg/Ca partitioning, and temperature. Validation of our Raman technique for corals is difficult because there are presently no direct measurements of calcifying fluid ΩAr available for comparison. However, Raman analysis of the international coral standard JCp-1 produced ΩAr of 12.3 ± 0.3, which we demonstrate is consistent with published skeletal Mg/Ca, Sr/Ca, B/Ca, δ11B, and δ44Ca data. Raman measurements are rapid ( ≤ 1 s), high-resolution ( ≤ 1 µm), precise (derived ΩAr ± 1 to 2 per spectrum depending on instrument configuration), accurate ( ±2 if ΩAr cultured under elevated CO2 and temperature.

  8. Archaeol: An Indicator of Methanogenesis in Water-Saturated Soils

    Directory of Open Access Journals (Sweden)

    Katie L. H. Lim

    2012-01-01

    Full Text Available Oxic soils typically are a sink for methane due to the presence of high-affinity methanotrophic Bacteria capable of oxidising methane. However, soils experiencing water saturation are able to host significant methanogenic archaeal communities, potentially affecting the capacity of the soil to act as a methane sink. In order to provide insight into methanogenic populations in such soils, the distribution of archaeol in free and conjugated forms was investigated as an indicator of fossilised and living methanogenic biomass using gas chromatography-mass spectrometry with selected ion monitoring. Of three soils studied, only one organic matter-rich site contained archaeol in quantifiable amounts. Assessment of the subsurface profile revealed a dominance of archaeol bound by glycosidic headgroups over phospholipids implying derivation from fossilised biomass. Moisture content, through control of organic carbon and anoxia, seemed to govern trends in methanogen biomass. Archaeol and crenarchaeol profiles differed, implying the former was not of thaumarcheotal origin. Based on these results, we propose the use of intact archaeol as a useful biomarker for methanogen biomass in soil and to track changes in moisture status and aeration related to climate change.

  9. [Digitalization without saturation dose using methyldigoxin. Experiences with 29 patients].

    Science.gov (United States)

    Salvadè, G; Tartini, R; Moccetti, T

    1982-12-11

    The indications and performance of oral digitalization without saturation dose are evaluated on the basis of clinical parameters and plasma digitalis levels. A group of patients with evident cardiac insufficiency received a daily maintenance dosage of digitalis (2 tablets of 0.1 mg methyldigoxin) from the outset. After 7, 15 and 30 days the plasma concentration of methyldigoxin was measured. Objective and subjective signs of cardiac insufficiency were noted. In 28 of 29 patients the therapeutic plasma level (0.8-2.0 ng/ml) was achieved with a mean plasma digitalis concentration of 1.47 +/- 0.4 ng/ml. A clinical improvement was observed in 18 patients. On the 15th and 30th day of treatment the mean plasma level of methyldigoxin showed no significant difference: X15 = 1.51 +/- 0.57 ng/ml and X30 = 1.40 +/- 0.46 ng/ml. The measured plasma values were not influenced by the patient's weight or age. In 6 patients with renal insufficiency a clear correlation between the plasma level of methyldigoxin and the creatinine level was observed. The evaluation of ECG signs showed only minimal alterations of conduction and repolarisation. On the basis of these results conclusions are drawn with regard to the clinical value and use of this therapy.

  10. Laser-saturated fluorescence measurements in laminar sooting diffusion flames

    Science.gov (United States)

    Wey, Changlie

    1993-01-01

    The hydroxyl radical is known to be one of the most important intermediate species in the combustion processes. The hydroxyl radical has also been considered a dominant oxidizer of soot particles in flames. In this investigation the hydroxyl concentration profiles in sooting diffusion flames were measured by the laser-saturated fluorescence (LSF) method. The temperature distributions in the flames were measured by the two-line LSF technique and by thermocouple. In the sooting region the OH fluorescence was too weak to make accurate temperature measurements. The hydroxyl fluorescence profiles for all four flames presented herein show that the OH fluorescence intensities peaked near the flame front. The OH fluorescence intensity dropped sharply toward the dark region of the flame and continued declining to the sooting region. The OH fluorescence profiles also indicate that the OH fluorescence decreased with increasing height in the flames for all flames investigated. Varying the oxidizer composition resulted in a corresponding variation in the maximum OH concentration and the flame temperature. Furthermore, it appears that the maximum OH concentration for each flame increased with increasing flame temperature.

  11. Determination of saturated aliphatic hydrocarbons in vegetable oils

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Coca, R.B.; Cert, R.; Perez Camino, M.C.; Moreda, W.

    2016-07-01

    The aim of this work is to inform about the development of a simple and reliable off-line method for the determination of saturated hydrocarbons (SH) in vegetable oils. SH can be used as markers for fuel or for mineral oil contamination in edible oils and fats. The method consists of the isolation of the fraction by LC on deactivated silver-silica gel and subsequent on-column GC-FID analysis. This stationary phase was prepared avoiding any kind of activation. The method was developed and validated through the participation in both a proficiency test organized by the Joint Research Centre of the European Commission, and a collaborative trial carried out with trained Spanish laboratories according to the standard ISO 5725. Results showed acceptable repeatability and reproducibility values, and Horrat index, being this protocol in use with satisfactory results ever since. The method’s LOQ is 15 mg·kg–1 and its LOD 5 mg·kg–1, which make it suitable to quantify the 50 mg·kg–1 limit established by the EU, and to detect mineral oil content within the 10–500 mg·kg–1 range. Although other procedures with lower LOD have been developed throughout the years, the use of just regular laboratory equipment such as GC-FID makes the proposed method appropriate for application on a routine basis. (Author)

  12. Optimal control of metabolic networks with saturable enzyme kinetics.

    Science.gov (United States)

    Oyarzuun, D A

    2011-03-01

    This note addresses the optimal control of non-linear metabolic networks by means of time-dependent enzyme synthesis rates. The authors consider networks with general topologies described by a control-affine dynamical system coupled with a linear model for enzyme synthesis and degradation. The problem formulation accounts for transitions between two metabolic equilibria, which typically arise in metabolic adaptations to environmental changes, and the minimisation of a quadratic functional that weights the cost/benefit relation between the transcriptional effort required for enzyme synthesis and the transition to the new phenotype. Using a linear time-variant approximation of the non-linear dynamics, the problem is recast as a sequence of linear-quadratic problems, the solution of which involves a sequence of differential Lyapunov equations. The authors provide conditions for convergence to an approximate solution of the original problem, which are naturally satisfied by a wide class of models for saturable enzyme kinetics. As a case study the authors use the method to examine the robustness of an optimal just-in-time gene expression pattern with respect to heterogeneity in the biosynthetic costs of individual proteins.

  13. Monte Carlo simulation of AB-copolymers with saturating bonds

    CERN Document Server

    Chertovich, A V; Khokhlov, A R; Bohr, J

    2003-01-01

    Structural transitions in a single AB-copolymer chain where saturating bonds can be formed between A-and B-units are studied by means of Monte Carlo computer simulations using the bond fluctuation model. Three transitions are found, coil-globule, coil-hairpin and globule-hairpin, depending on the nature of a particular AB-sequence: statistical random sequence, diblock sequence and 'random-complementary' sequence (one-half of such an AB-sequence is random with Bernoulli statistics while the other half is complementary to the first one). The properties of random-complementary sequences are closer to those of diblock sequences than to the properties of random sequences. The model (although quite rough) is expected to represent some basic features of real RNA molecules, i.e. the formation of secondary structure of RNA due to hydrogen bonding of corresponding bases and stacking interactions of the base pairs in helixes. We introduce the notation of RNA-like copolymers and discuss in what sense the sequences studie...

  14. Terahertz saturable absorbers from liquid phase exfoliation of graphite.

    Science.gov (United States)

    Bianchi, Vezio; Carey, Tian; Viti, Leonardo; Li, Lianhe; Linfield, Edmund H; Davies, A Giles; Tredicucci, Alessandro; Yoon, Duhee; Karagiannidis, Panagiotis G; Lombardi, Lucia; Tomarchio, Flavia; Ferrari, Andrea C; Torrisi, Felice; Vitiello, Miriam S

    2017-06-15

    Saturable absorbers (SA) operating at terahertz (THz) frequencies can open new frontiers in the development of passively mode-locked THz micro-sources. Here we report the fabrication of THz SAs by transfer coating and inkjet printing single and few-layer graphene films prepared by liquid phase exfoliation of graphite. Open-aperture z-scan measurements with a 3.5 THz quantum cascade laser show a transparency modulation ∼80%, almost one order of magnitude larger than that reported to date at THz frequencies. Fourier-transform infrared spectroscopy provides evidence of intraband-controlled absorption bleaching. These results pave the way to the integration of graphene-based SA with electrically pumped THz semiconductor micro-sources, with prospects for applications where excitation of specific transitions on short time scales is essential, such as time-of-flight tomography, coherent manipulation of quantum systems, time-resolved spectroscopy of gases, complex molecules and cold samples and ultra-high speed communications, providing unprecedented compactness and resolution.

  15. SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    M. Batzle; D-h Han; R. Gibson; O. Djordjevic

    2003-03-20

    The ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' (Grant/Cooperative Agreement DE-FC26-02NT15342) began September 1, 2002. During this second quarter: A Direct Hydrocarbon Indicator (DHI) symposium was held at UH; Current DHI methods were presented and forecasts made on future techniques; Dr. Han moved his laboratory from HARC to the University of Houston; Subcontracts were re-initiated with UH and TAMU; Theoretical and numerical modeling work began at TAMU; Geophysical Development Corp. agreed to provide petrophysical data; Negotiations were begun with Veritas GDC to obtain limited seismic data; Software licensing and training schedules were arranged with Paradigm; and Data selection and acquisition continues. The broad industry symposium on Direct Hydrocarbon Indicators was held at the University of Houston as part of this project. This meeting was well attended and well received. A large amount of information was presented, not only on application of the current state of the art, but also on expected future trends. Although acquisition of appropriate seismic data was expected to be a significant problem, progress has been made. A 3-D seismic data set from the shelf has been installed at Texas A&M University and analysis begun. Veritas GDC has expressed a willingness to provide data in the deep Gulf of Mexico. Data may also be available from TGS.

  16. Terahertz saturable absorbers from liquid phase exfoliation of graphite

    Science.gov (United States)

    Bianchi, Vezio; Carey, Tian; Viti, Leonardo; Li, Lianhe; Linfield, Edmund H.; Davies, A. Giles; Tredicucci, Alessandro; Yoon, Duhee; Karagiannidis, Panagiotis G.; Lombardi, Lucia; Tomarchio, Flavia; Ferrari, Andrea C.; Torrisi, Felice; Vitiello, Miriam S.

    2017-06-01

    Saturable absorbers (SA) operating at terahertz (THz) frequencies can open new frontiers in the development of passively mode-locked THz micro-sources. Here we report the fabrication of THz SAs by transfer coating and inkjet printing single and few-layer graphene films prepared by liquid phase exfoliation of graphite. Open-aperture z-scan measurements with a 3.5 THz quantum cascade laser show a transparency modulation ~80%, almost one order of magnitude larger than that reported to date at THz frequencies. Fourier-transform infrared spectroscopy provides evidence of intraband-controlled absorption bleaching. These results pave the way to the integration of graphene-based SA with electrically pumped THz semiconductor micro-sources, with prospects for applications where excitation of specific transitions on short time scales is essential, such as time-of-flight tomography, coherent manipulation of quantum systems, time-resolved spectroscopy of gases, complex molecules and cold samples and ultra-high speed communications, providing unprecedented compactness and resolution.

  17. Investigation of the kinetics of water uptake into partially saturated shales

    National Research Council Canada - National Science Library

    Roshan, H; Andersen, M. S; Rutlidge, H; Marjo, C. E; Acworth, R. I

    2016-01-01

    .... This study describes novel hydraulic experiments to quantitatively investigate the kinetics of water uptake into partially saturated shale through investigating the pressure response of injecting fluids...

  18. Properties of InGaAs quantum dot saturable absorbers in monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Thompson, M.G.; Marinelli, C.; Chu, Y.

    Saturable absorbers properties are characterised in monolithic mode-locked InGaAs quantum dot lasers. We analyse the impact of weak quantum confined Stark effect, fast absorber recovery time and low absorber saturation power on the mode-locking performance.......Saturable absorbers properties are characterised in monolithic mode-locked InGaAs quantum dot lasers. We analyse the impact of weak quantum confined Stark effect, fast absorber recovery time and low absorber saturation power on the mode-locking performance....

  19. Numerical Study of Frequency-dependent Seismoelectric Coupling in Partially-saturated Porous Media

    Directory of Open Access Journals (Sweden)

    Djuraev Ulugbek

    2017-01-01

    Full Text Available The seismoelectric phenomenon associated with propagation of seismic waves in fluid-saturated porous media has been studied for many decades. The method has a great potential to monitor subsurface fluid saturation changes associated with production of hydrocarbons. Frequency of the seismic source has a significant impact on measurement of the seismoelectric effects. In this paper, the effects of seismic wave frequency and water saturation on the seismoelectric response of a partially-saturated porous media is studied numerically. The conversion of seismic wave to electromagnetic wave was modelled by extending the theoretically developed seismoelectric coupling coefficient equation. We assumed constant values of pore radius and zeta-potential of 80 micrometers and 48 microvolts, respectively. Our calculations of the coupling coefficient were conducted at various water saturation values in the frequency range of 10 kHz to 150 kHz. The results show that the seismoelectric coupling is frequency-dependent and decreases exponentially when frequency increases. Similar trend is seen when water saturation is varied at different frequencies. However, when water saturation is less than about 0.6, the effect of frequency is significant. On the other hand, when the water saturation is greater than 0.6, the coupling coefficient shows monotonous trend when water saturation is increased at constant frequency.

  20. Saturated Fats and Cardiovascular Disease: Interpretations Not as Simple as They Once Were.

    Science.gov (United States)

    Bier, Dennis M

    2016-09-09

    Historically, the so-called "lipid hypothesis" has focused on the detrimental role of saturated fats per se in enhancing the risks of cardiovascular disease. Recently, a body of new information and systematic analyses of available data have questioned simple interpretation of the relationship of dietary saturated fats and of individual saturated fatty acids to CVD risk. Thus, current assessments of risks due to dietary fat consumption that emphasize the confounding nature of the dietary macronutrients substituted for dietary saturated fats and give broader recognition to the effect of patterns of food intake as a whole are the most productive approach to an overall healthy diet.

  1. [Sampling in qualitative research: a proposal for procedures to detect theoretical saturation].

    Science.gov (United States)

    Fontanella, Bruno Jose Barcellos; Luchesi, Bruna Moretti; Saidel, Maria Giovana Borges; Ricas, Janete; Turato, Egberto Ribeiro; Melo, Débora Gusmão

    2011-02-01

    A qualitative study's methodological transparency is considered a key factor for achieving its reliability and should be guaranteed by the researchers. Closing the sampling process by saturation is a common approach, but it is rarely made explicit in research reports. Qualitative researchers also commonly experience technical difficulties in objectively identifying saturation. This article proposes a method to organize sample closing by saturation, with a sequence of eight procedural steps for treating and analyzing data collected through open or semi-structured interviews or focus groups. The article aims to help researchers objectively explain how and when saturation occurred and to allow their readers to know how this process occurred.

  2. Nonlinearly limited saturable-absorber mode locking of an erbium fiber laser.

    Science.gov (United States)

    Jiang, M; Sucha, G; Fermann, M E; Jimenez, J; Harter, D; Dagenais, M; Fox, S; Hu, Y

    1999-08-01

    We describe an erbium fiber laser that is passively mode locked by a novel, precision antireflection-coated semiconductor saturable-absorber mirror that incorporates an additional two-photon absorber. It is shown that passive mode locking evolves from a Q-switching instability. The results are achieved by use of saturable absorbers that provide a large (15%) nonlinear (saturable) loss. Exploiting two-photon absorption can substantially reduce the peak power of the Q-switched pulses, which results in improved reliability of the laser. Moreover, two-photon absorption can be used to produce an optimal stability range for saturable-absorber mode locking.

  3. Complex conductivity results to silver nanoparticles in partically saturated laboratory columns

    Data.gov (United States)

    U.S. Environmental Protection Agency — Laboratory complex conductivity data from partially saturated sand columns with silver nanoparticles. This dataset is not publicly accessible because: It involves...

  4. Propagation des ondes acoustiques dans les milieux poreux saturés Propagation of Acoustic Waves in Saturated Porous Media

    Directory of Open Access Journals (Sweden)

    Coussy O.

    2006-11-01

    Full Text Available Ce travail comporte deux parties. La première partie concerne la théorie de la propagation des ondes acoustiques dans les milieux poreux saturés. Une revue des différentes méthodes existantes est faite et un développement critique de la théorie de Biot est exposé en détail. On examine en particulier les différents résultats auxquels cette théorie conduit et on regarde, dans quelles conditions et sur quels problèmes géophysiques, les phénomènes physiques mis en évidence peuvent jouer de manière notable. Dans la deuxième partie, on présente une vérification expérimentale due à Plona (1980 de la théorie de Biot. Après une introduction qualitative de l'expérience mise en place, on expose les résultats obtenus pour un grand nombre de matériaux de porosités différentes. La notion de tortuosité d'un milieu poreux est introduite théoriquement et discutée expérimentalement. This article is in two parts. The first part has to do with the theory of acoustic wave propagation in saturated porous media. Different existing methods are reviewed, and Biot's theory is critically developed in detail. In particular, the different results to which this theory leads are examined, and the conditions and geophysical problems on which the physical phenomena involved may have an appreciable effect are considered. The second part is devoted to the experimental check made by Plona (1980 of Biot's theory. After a qualitative introduction of the experimental procedure, the results obtained for many materials of different porosities are described. The concept of the tortuosity of a porous medium is introduced theoretically and discussed experimentally.

  5. A systematic review of the effect of dietary saturated and polyunsaturated fat on heart disease.

    Science.gov (United States)

    Clifton, P M; Keogh, J B

    2017-12-01

    Over the last 7 years there has been intense debate about the advice to reduce saturated fat and increase polyunsaturated fat to reduce CVD risk. The aim of this review was to examine systematic reviews and meta-analyses since 2010 on this topic plus additional cohort studies and interventions not included in these reviews. High saturated and trans fat intake (which elevates LDL like saturated fat) in the Nurses and Health Professional Follow-Up Studies combined is associated with an 8-13% higher mortality and replacement of saturated fat with any carbohydrate, PUFA and MUFA is associated with lower mortality with PUFA being more effective than MUFA (19% reduction versus 11%). With CVD mortality only PUFA and fish oil replacement of saturated fat lowers risk with a 28% reduction in CVD mortality per 5% of energy. Replacing saturated fat with PUFA or MUFA is equally effective at reducing CHD events and replacement with whole grains will lower events while replacement with sugar and starch increases events. Replacement of saturated fat with carbohydrate has no effect on CHD events or death. Only PUFA replacement of saturated fat lowers CHD events and CVD and total mortality. Replacing saturated fat with linoleic acid appears to be beneficial based on the Hooper Cochrane meta-analysis of interventions although other analyses with fewer studies have shown no effect. Reducing saturated fat and replacing it with carbohydrate will not lower CHD events or CVD mortality although it will reduce total mortality. Replacing saturated fat with PUFA, MUFA or high-quality carbohydrate will lower CHD events. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

  6. An XFEM Model for Hydraulic Fracturing in Partially Saturated Rocks

    Directory of Open Access Journals (Sweden)

    Salimzadeh Saeed

    2016-01-01

    Full Text Available Hydraulic fracturing is a complex multi-physics phenomenon. Numerous analytical and numerical models of hydraulic fracturing processes have been proposed. Analytical solutions commonly are able to model the growth of a single hydraulic fracture into an initially intact, homogeneous rock mass. Numerical models are able to analyse complex problems such as multiple hydraulic fractures and fracturing in heterogeneous media. However, majority of available models are restricted to single-phase flow through fracture and permeable porous rock. This is not compatible with actual field conditions where the injected fluid does not have similar properties as the host fluid. In this study we present a fully coupled hydro-poroelastic model which incorporates two fluids i.e. fracturing fluid and host fluid. Flow through fracture is defined based on lubrication assumption, while flow through matrix is defined as Darcy flow. The fracture discontinuity in the mechanical model is captured using eXtended Finite Element Method (XFEM while the fracture propagation criterion is defined through cohesive fracture model. The discontinuous matrix fluid velocity across fracture is modelled using leak-off loading which couples fracture flow and matrix flow. The proposed model has been discretised using standard Galerkin method, implemented in Matlab and verified against several published solutions. Multiple hydraulic fracturing simulations are performed to show the model robustness and to illustrate how problem parameters such as injection rate and rock permeability affect the hydraulic fracturing variables i.e. injection pressure, fracture aperture and fracture length. The results show the impact of partial saturation on leak-off and the fact that single-phase models may underestimate the leak-off.

  7. Saturated porous continua in the frame of hybrid description

    Science.gov (United States)

    Brazgina, Olga V.; Ivanova, Elena A.; Vilchevskaya, Elena N.

    2016-09-01

    A method for modeling fluid-solid interactions in saturated porous media is proposed. The main challenge is the combination of the material and spatial descriptions. The deformation of the solid, which serves as a "container" to the fluid, is studied by following the motion of its material particles, i.e., in Lagrangian description. On the other hand, the motion of the fluid is described in spatial form, i.e., by using a Eulerian approach. However, the solid deforms and this implies a certain difference regarding the standard formulation used in spatial description of fluid mechanics where a fixed grid dissects space into elementary volumes. Here the grid is no longer fixed, and the elementary volumes will follow the deformation of the solid. Moreover, for the solid as well as for the fluid the balance equations are formulated in the current configuration, where interaction forces and couples are taken into account. By using Zhilin's approach, entropy and temperature are incorporated in the system of equations. Constitutive equations are constructed for both elastic and inelastic components of force and couple stress tensors and interaction force and couple. The constitutive equations for elastic components are found on the basis of the energy balance equation; the constitutive equations for the inelastic components are proposed in accordance with the second law of thermodynamics. Particular emphasis is placed on the constitutive equations of the interaction force and couple, which result in a symmetric form only because of the "hybrid" approach combining the Lagrangian with the Eulerian description. Three possible examples of application of the theory have been presented. For each example, all required assumptions were first stated and discussed and then the complete set of the corresponding equations was presented.

  8. Saturated hydraulic conductivity and porosity within macroaggregates modified by tillage

    Energy Technology Data Exchange (ETDEWEB)

    Park, E.J.; Smucker, A.J.M. (MSU)

    2010-07-20

    Greater knowledge of intraaggregate porosity modifications by tillage conveys new information for identifying additional hydrologic, ion retention, and aggregate stability responses to specific management practices. Macroaggregates, 2 to 4, 4 to 6.3, and 6.3 to 9.5 mm across, were separated into multiple concentric layers and their porosities were determined. Saturated hydraulic conductivity (K{sub s}) of multiple aggregate fractions from two soil types subjected to conventional tillage (CT), no tillage (NT), and native forest (NF) soils were measured individually to identify the effects of tillage on aggregate structure, porosity, and K{sub s}. Intraaggregate porosities were the highest in NF aggregates. Greater porosities were identified in exterior layers of soil aggregates from all treatments. Lowest intraaggregate porosities were observed in the central regions of CT aggregates. Soil aggregates, 6.3 to 9.5 mm across, had the greatest total porosities, averaging 37.5% for both soil types. Long-term CT reduced intraaggregate porosities and K, within macroaggregates, of the same size fraction, from both the Hoytville silty clay loam and Wooster silt loam soil types. Values for K, of NF aggregates, 5.0 x 10{sup -5} cm s{sup -1}, were reduced 50-fold by long-term CT treatments of the Hoytville series. The K, values through Wooster aggregates from NF, 16.0 x 10{sup -5} cm s{sup -1}, were reduced 80-fold by long-term CT treatments. The K{sub s} values through NF and NT aggregates were positively correlated with their intraaggregate porosities (R{sup 2} = 0.84 for NF and R{sup 2} = 0.45 for NT at P < 0.005). Additional studies are needed to identify rates at which pore geometries within macroaggregates are degraded by CT or improved by NT.

  9. Modelling carbon and nitrogen turnover in variably saturated soils

    Science.gov (United States)

    Batlle-Aguilar, J.; Brovelli, A.; Porporato, A.; Barry, D. A.

    2009-04-01

    Natural ecosystems provide services such as ameliorating the impacts of deleterious human activities on both surface and groundwater. For example, several studies have shown that a healthy riparian ecosystem can reduce the nutrient loading of agricultural wastewater, thus protecting the receiving surface water body. As a result, in order to develop better protection strategies and/or restore natural conditions, there is a growing interest in understanding ecosystem functioning, including feedbacks and nonlinearities. Biogeochemical transformations in soils are heavily influenced by microbial decomposition of soil organic matter. Carbon and nutrient cycles are in turn strongly sensitive to environmental conditions, and primarily to soil moisture and temperature. These two physical variables affect the reaction rates of almost all soil biogeochemical transformations, including microbial and fungal activity, nutrient uptake and release from plants, etc. Soil water saturation and temperature are not constants, but vary both in space and time, thus further complicating the picture. In order to interpret field experiments and elucidate the different mechanisms taking place, numerical tools are beneficial. In this work we developed a 3D numerical reactive-transport model as an aid in the investigation the complex physical, chemical and biological interactions occurring in soils. The new code couples the USGS models (MODFLOW 2000-VSF, MT3DMS and PHREEQC) using an operator-splitting algorithm, and is a further development an existing reactive/density-dependent flow model PHWAT. The model was tested using simplified test cases. Following verification, a process-based biogeochemical reaction network describing the turnover of carbon and nitrogen in soils was implemented. Using this tool, we investigated the coupled effect of moisture content and temperature fluctuations on nitrogen and organic matter cycling in the riparian zone, in order to help understand the relative

  10. Cotransport of bismerthiazol and montmorillonite colloids in saturated porous media.

    Science.gov (United States)

    Shen, Chongyang; Wang, Hong; Lazouskaya, Volha; Du, Yichun; Lu, Weilan; Wu, Junxue; Zhang, Hongyan; Huang, Yuanfang

    2015-01-01

    While bismerthiazol [N,N'-methylene-bis-(2-amino-5-mercapto-1,3,4-thiadiazole)] is one of the most widely used bactericides, the transport of bismerthiazol in subsurface environments is unclear to date. Moreover, natural colloids are ubiquitous in the subsurface environments. The cotransport of bismerthiazol and natural colloids has not been investigated. This study conducted laboratory column experiments to examine the transport of bismerthiazol in saturated sand porous media both in the absence and presence of montmorillonite colloids. Results show that a fraction of bismerthiazol was retained in sand and the retention was higher at pH7 than at pH 4 and 10. The retention did not change with ionic strength. The retention was attributed to the complex of bismerthiazol with metals/metal oxides on sand surfaces through ligand exchange. The transport of bismerthiazol was enhanced with montmorillonite colloids copresent in the solutions and, concurrently, the transport of montmorillonite colloids was facilitated by the bismerthiazol. The transport of montmorillonite colloids was enhanced likely because the bismerthiazol and the colloids competed for the attachment/adsorption sites on collector surfaces and the presence of bismerthiazol changed the Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energies between colloids and collectors. The transport of bismerthiazol was inhibited if montmorillonite colloids were pre-deposited in sand because bismerthiazol could adsorb onto the colloid surfaces. The adsorbed bismerthiazol could be co-remobilized with the colloids from primary minima by decreasing ionic strength. Whereas colloid-facilitated transport of pesticides has been emphasized, our study implies that transport of colloids could also be facilitated by the presence of pesticides. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Measuring lateral saturated soil hydraulic conductivity at different spatial scales

    Science.gov (United States)

    Di Prima, Simone; Marrosu, Roberto; Pirastru, Mario; Niedda, Marcello

    2017-04-01

    Among the soil hydraulic properties, saturated soil hydraulic conductivity, Ks, is particularly important since it controls many hydrological processes. Knowledge of this soil property allows estimation of dynamic indicators of the soil's ability to transmit water down to the root zone. Such dynamic indicators are valuable tools to quantify land degradation and developing 'best management' land use practice (Castellini et al., 2016; Iovino et al., 2016). In hillslopes, lateral saturated soil hydraulic conductivity, Ks,l, is a key factor since it controls subsurface flow. However, Ks,l data collected by point-scale measurements, including infiltrations tests, could be unusable for interpreting field hydrological processes and particularly subsurface flow in hillslopes. Therefore, they are generally not representative of subsurface processes at hillslope-scale due mainly to soil heterogeneities and the unknown total extent and connectivity of macropore network in the porous medium. On the other hand, large scale Ks,l measurements, which allow to average soil heterogeneities, are difficult and costly, thus remain rare. Reliable Ks,l values should be measured on a soil volume similar to the representative elementary volume (REV) in order to incorporate the natural heterogeneity of the soil. However, the REV may be considered site-specific since it is expected to increase for soils with macropores (Brooks et al., 2004). In this study, laboratory and in-situ Ks,l values are compared in order to detect the dependency Ks,l from the spatial scale of investigation. The research was carried out at a hillslope located in the Baratz Lake watershed, in northwest Sardinia, Italy, characterized by degraded vegetation (grassland established after fire or clearing of the maquis). The experimental area is about 60 m long, with an extent of approximately 2000 m2, and a mean slope of 30%. The soil depth is about 35 to 45 cm. The parent material is a very dense grayish, altered

  12. Effect of solution saturation state and temperature on diopside dissolution

    Directory of Open Access Journals (Sweden)

    Carroll Susan A

    2007-03-01

    Full Text Available Abstract Steady-state dissolution rates of diopside are measured as a function of solution saturation state using a titanium flow-through reactor at pH 7.5 and temperature ranging from 125 to 175°C. Diopside dissolved stoichiometrically under all experimental conditions and rates were not dependent on sample history. At each temperature, rates continuously decreased by two orders of magnitude as equilibrium was approached and did not exhibit a dissolution plateau of constant rates at high degrees of undersaturation. The variation of diopside dissolution rates with solution saturation can be described equally well with a ion exchange model based on transition state theory or pit nucleation model based on crystal growth/dissolution theory from 125 to 175°C. At 175°C, both models over predict dissolution rates by two orders of magnitude indicating that a secondary phase precipitated in the experiments. The ion exchange model assumes the formation of a Si-rich, Mg-deficient precursor complex. Lack of dependence of rates on steady-state aqueous calcium concentration supports the formation of such a complex, which is formed by exchange of protons for magnesium ions at the surface. Fit to the experimental data yields Rate (moldiopsidecm−2s−1=k×10−Ea/2.303RT(aH+2aMg2+n MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaaieaacqWFsbGucqWFHbqycqWF0baDcqWFLbqzcqqGGaaicqGGOaakcqWFTbqBcqWFVbWBcqWFSbaBcqWFGaaicqWFKbazcqWFPbqAcqWFVbWBcqWFWbaCcqWFZbWCcqWFPbqAcqWFKbazcqWFLbqzcqWFGaaicqWFJbWycqWFTbqBdaahaaWcbeqaaiabgkHiTiabikdaYaaakiab=bcaGiab=nhaZnaaCaaaleqabaGaeyOeI0IaeGymaedaaOGaeiykaKIaeyypa0Jaem4AaSMaey41aqRaeeymaeJaeeimaaZaaWbaaSqabeaacqGHsislcqWGfbqrdaWgaaadbaGaemyyaegabeaaliabc+caViabikdaYiabc6caUiabioda

  13. Biotransformation of pesticides in saturated-zone materials

    Science.gov (United States)

    Hoyle, Blythe L.; Arthur, Ellen L.

    Many studies have been conducted to evaluate pesticide contamination of groundwater in the United States, but investigations of pesticide biotransformation in saturated zones are much less numerous than in surface soils. Because results of studies using soils are not directly applicable to the subsurface, the purpose of this paper is to illustrate examples of pesticide biotransformation in saturated-zone materials. Although it must be considered with caution, the US Environmental Protection Agency's (EPA) "Pesticides in Ground Water Database" was used to focus the discussion on the biotransformation potential of dibromoethane (EDB), atrazine, acetanilide herbicides, and aldicarb, all of which have been detected in groundwater in the United States. Results of more than two dozen studies indicate that a biotransformation potential for these pesticides exists in saturated-zone materials, although for any given pesticide substantial differences in biotransformation occurred. These variations were due both to differences in experimental methods and to heterogeneities in the subsurface materials under investigation. However, because biotransformation mechanisms were not well investigated, it is generally not possible to extrapolate predictions of biotransformation potential beyond the specific sites investigated. These results highlight the need to better understand microbial genetic regulation of biotransformation processes so that genetic information may be effectively incorporated into future investigations of biotransformation potential in the subsurface. Résumé De nombreuses études ont été réalisées pour évaluer le degré de pollution des aquifères par les pesticides aux États-Unis, mais les recherches concernant la biotransformation des pesticides dans les eaux souterraines sont beaucoup moins nombreuses que dans les sols. Du fait que les résultats des études concernant les sols ne sont pas directement applicables au milieu souterrain, le propos de cet

  14. Impact of Gain Saturation on the Parametric Amplification of 16-QAM Signals

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Borkowski, Robert; Zibar, Darko

    2012-01-01

    The effect of gain saturation on parametric amplification of 16-QAM signals is investigated in terms of signal distortion. The relative impact of gain saturation, nonlinear phase rotation and nonlinear phase noise is discussed. Experimental results at 14 GBd confirm the conclusions of the numerical...

  15. Impact of gain saturation on the mode instability threshold in high-power fiber amplifiers

    DEFF Research Database (Denmark)

    Hansen, Kristian Rymann; Lægsgaard, Jesper

    2014-01-01

    We present a coupled-mode model of transverse mode instability in high-power fiber amplifiers, which takes the effect of gain saturation into account. The model provides simple semi-analytical formulas for the mode instability threshold, which are valid also for highly saturated amplifiers...

  16. Extension of semi-analytical Erbium-doped fiber amplifier model to self-saturation regime

    DEFF Research Database (Denmark)

    Nissov, Morten

    1997-01-01

    We show in this paper that the analytical erbium-doped fiber amplifier (EDFA) model presented by Jopson and Saleh in 1991 can be extended to the self-saturation regime, making it capable of simulating all practical EDFAs. We show that an Intel Pentium 66 based computer can calculate gain and noise...... figure for a counterdirectionally pumped self-saturated amplifier in

  17. The accuracy of the Hewlett-Packard 47201A ear oximeter below 50% saturation.

    Science.gov (United States)

    Stradling, J R

    1982-01-01

    The Hewlett-Packard 47201A ear oximeter has been shown to measure arterial oxygen saturation (SaO2) above 50% SaO2 with an accuracy of +/- 5%. Below 50% SaO2, the oximeter underestimates arterial saturation in a predictable way, thus allowing a correction factor to be used: true SaO2 = (oximeter reading + 50)/2.

  18. The relation of saturated fatty acids with low-grade inflammation and cardiovascular disease

    NARCIS (Netherlands)

    Ruiz-Nunez, Begona; Dijck-Brouwer, D. A. Janneke; Muskiet, Frits A. J.

    2016-01-01

    The mantra that dietary (saturated) fat must be minimized to reduce cardiovascular disease (CVD) risk has dominated nutritional guidelines for decades. Parallel to decreasing intakes of fat and saturated fatty acids (SFA), there have been increases in carbohydrate and sugar intakes, overweight,

  19. No agreement of mixed venous and central venous saturation in sepsis, independent of sepsis origin

    NARCIS (Netherlands)

    van Beest, Paul A.; van Ingen, Jan; Boerma, E. Christiaan; Holman, Nicole D.; Groen, Henk; Koopmans, Matty; Spronk, Peter E.; Kuiper, Michael A.

    2010-01-01

    Controversy remains regarding the relationship between central venous saturation (ScvO(2)) and mixed venous saturation (SvO(2)) and their use and interchangeability in patients with sepsis or septic shock. We tested the hypothesis that ScvO(2) does not reliably predict SvO(2) in sepsis. Additionally

  20. Regional assessment of N saturation using foliar and root δ15N

    Science.gov (United States)

    L.H. Pardo; P.H. Templer; C.L. Goodale; S. Duke; P.M. Groffman; M.B. Adams; P. Boeckx; J. Boggs; J. Campbell; B. Colman; J. Compton; B. Emmett; P. Gundersen; J. Kjonaas; G. Lovett; M. Mack; A. Magill; M. Mbila; M.J. Mitchell; G. McGee; S. McNulty; K. Nadelhoffer; S. Ollinger; D. Ross; H. Rueth; L. Rustad; P. Schaberg; S. Schiff; P. Schleppi; J. Spoelstra; W. Wessel

    2006-01-01

    N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar δ15N may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root δ

  1. Ocean acidification and calcium carbonate saturation states in the coastal zone of the West Antarctic Peninsula

    NARCIS (Netherlands)

    Jones, Elizabeth M.; Fenton, Mairi; Meredith, Michael P.; Clargo, Nicola M.; Ossebaar, Sharyn; Ducklow, Hugh W.; Venables, Hugh J.; de Baar, Henricus

    The polar oceans are particularly vulnerable to ocean acidification; the lowering of seawater pH and carbonate mineral saturation states due to uptake of atmospheric carbon dioxide (CO2). High spatial variability in surface water pH and saturation states (Omega) for two biologically-important

  2. Research on evaluation method for water saturation of tight sandstone in Suxi region

    Science.gov (United States)

    Lv, Hong; Lai, Fuqiang; Chen, Liang; Li, Chao; Li, Jie; Yi, Heping

    2017-05-01

    The evaluation of irreducible water saturation is important for qualitative and quantitative prediction of residual oil distribution. However, it is to be improved for the accuracy of experimental measuring the irreducible water saturation and logging evaluation. In this paper, firstly the multi-functional core flooding experiment and the nuclear magnetic resonance centrifugation experiment are carried out in the west of Sulige gas field. Then, the influence was discussed about particle size, porosity and permeability on the water saturation. Finally, the evaluation model was established about irreducible water saturation and the evaluation of irreducible water saturation was carried out. The results show that the results of two experiments are both reliable. It is inversely proportional to the median particle size, porosity and permeability, and is most affected by the median particle size. The water saturation of the dry layer is higher than that of the general reservoir. The worse the reservoir property, the greater the water saturation. The test results show that the irreducible water saturation model can be used to evaluate the water floor.

  3. Exact expression for the effective acoustics of patchy-saturated rocks

    NARCIS (Netherlands)

    Vogelaar, B.; Smeulders, D.M.J.; Harris, J.

    2010-01-01

    Seismic effects of a partially gas-saturated subsurface have been known for many years. For example, patches of nonuniform saturation occur at the gas-oil and gas-water contacts in hydrocarbon reservoirs. Open-pore boundary conditions are applied to the quasi-static Biot equations of poroelasticity

  4. Decentralized stabilization of linear time invariant systems subject to actuator saturation

    NARCIS (Netherlands)

    Stoorvogel, Antonie Arij; Saberi, Ali; Deliu, Ciprian; Deliu, C.; Sannuti, Peddapullaiah; Tarbouriech, S.; Garcia, G.; Glattfelder, A.H.

    2007-01-01

    We are concerned here with the stabilization of a linear time invariant system subject to actuator saturation via decentralized control while using linear time invariant dynamic controllers. When there exists no actuator saturation, i.e. when we consider just linear time invariant systems, it is

  5. BEHAVIOR OF AN IMMERSED CORE SAMPLE IN A FLUID CONTAINER DURING A SATURATION TECHNIQUE

    Directory of Open Access Journals (Sweden)

    S GHEBOULI

    2002-06-01

    Full Text Available The objective of this paper is to present the behavior of some core samples immersed in a  fluid container during a saturation technique. The experimental work was carried out by using two different fluids. The results obtained are similar except for the saturation stages. They are caused by different viscosities and surface tensions.

  6. Response of an anisotropic liquid-saturated porous medium due to ...

    Indian Academy of Sciences (India)

    Eigenvalue approach, following Laplace and Fourier transforms, has been employed to find the general solution to the field equations in an anisotropic liquid-saturated porous medium, in the transformed domain. The results of isotropic liquid-saturated porous medium can be derived as a special case. A numerical inversion ...

  7. Saturation Concentrations of Suspended Fine Sediment : Computations with the Prandtl Mixing-Length Model

    NARCIS (Netherlands)

    Kranenburg, C.

    1998-01-01

    Adopting a 1DV numerical model including the standard k-eps turbulence model, Winterwerp et al. (1999) calculated a saturation concentration for an initially uniform distribution of fine sediment concentration in steady flow. At concentrations exceeding the saturation concentration the concentration

  8. Chloride diffusivity in partially saturated cement-based materials assessed by resistivity measurements

    NARCIS (Netherlands)

    Zhang, Y.; Ye, G.

    2014-01-01

    Concrete is seldom saturated due to its self-desiccation. Even the submerged concrete structures may remain unsaturated for quite a long time. It has been reported the saturation level of pore solution has significant effect on species penetration. However, very little work was proposed regarding

  9. Saturation of sodium fluorescence in a flame irradiated with a pulsed tunable dye laser

    NARCIS (Netherlands)

    Calcar, R.A. van; Ven, M.J.M. van de; Uitert, B.K. van; Biewenga, K.J.; Hollander, Tj.; Alkemade, C.T.J.

    Theoretical and experimental saturation curves and associated saturation parameters for the Na-D doublet in an H2-O2-Ar flame at 1 atm (T=1700 K) are compared. These parameters are found to agree within the experimental error of 25%. An explanation based on the spatial and temporal distribution of

  10. Relation between electric properties and water saturation for hematitic sandstone with frequency

    Directory of Open Access Journals (Sweden)

    M. M. Gomaa

    2008-06-01

    Full Text Available This paper focuses on the effect of water saturation on A. C. electrical conductivity and dielectric constant of fully and partially saturated hematitic sandstone sample (Aswan area, Egypt. The saturation of the sample was changed from partial to full saturation. Complex resistivity measurements at room temperature (~16°C, were performed in the frequency range from 0.1 Hz to 100 KHz. Experimental electrical spectra indicate, generally, that the electrical conductivity and dielectric constant vary strongly with water saturations and frequency. The low frequency electrical conductivity and dielectric constant are mainly controlled by surface conduction and polarization of the electrical double layer. The behaviour of the electrical conductivity and dielectric constant, with increasing water content, were argued to the orientational polarization of bound water for very low saturations, displacement of the excess surface charges for relatively low saturations, and free exchange of excess ions in double layer with the bulk electrolyte and generation of transient diffusion potentials which lag behind the applied field for high saturations.

  11. Gas hydrate saturation from acoustic impedance and resistivity logs in the shenhu area, south china sea

    Science.gov (United States)

    Wang, X.; Wu, S.; Lee, M.; Guo, Y.; Yang, S.; Liang, J.

    2011-01-01

    During the China's first gas hydrate drilling expedition -1 (GMGS-1), gas hydrate was discovered in layers ranging from 10 to 25 m above the base of gas hydrate stability zone in the Shenhu area, South China Sea. Water chemistry, electrical resistivity logs, and acoustic impedance were used to estimate gas hydrate saturations. Gas hydrate saturations estimated from the chloride concentrations range from 0 to 43% of the pore space. The higher gas hydrate saturations were present in the depth from 152 to 177 m at site SH7 and from 190 to 225 m at site SH2, respectively. Gas hydrate saturations estimated from the resistivity using Archie equation have similar trends to those from chloride concentrations. To examine the variability of gas hydrate saturations away from the wells, acoustic impedances calculated from the 3 D seismic data using constrained sparse inversion method were used. Well logs acquired at site SH7 were incorporated into the inversion by establishing a relation between the water-filled porosity, calculated using gas hydrate saturations estimated from the resistivity logs, and the acoustic impedance, calculated from density and velocity logs. Gas hydrate saturations estimated from acoustic impedance of seismic data are ???10-23% of the pore space and are comparable to those estimated from the well logs. The uncertainties in estimated gas hydrate saturations from seismic acoustic impedances were mainly from uncertainties associated with inverted acoustic impedance, the empirical relation between the water-filled porosities and acoustic impedances, and assumed background resistivity. ?? 2011 Elsevier Ltd.

  12. Ocean acidification and calcium carbonate saturation states in the coastal zone of the West Antarctic Peninsula

    NARCIS (Netherlands)

    Jones, E.M.; Fenton, M.; Meredith, M.P.; Clargo, N.M.; Ossebaar, S.; Ducklow, H.W.; Venables, H.J.; De Baar, H.J.W.

    2017-01-01

    The polar oceans are particularly vulnerable to ocean acidification; the lowering of seawater pH and carbonate mineral saturation states due to uptake of atmospheric carbon dioxide (CO2). High spatial variability in surface water pH and saturation states (Ω) for two biologically-important calcium

  13. Simulated effects of nitrogen saturation the global carbon budget using the IBIS model

    Science.gov (United States)

    Lu, Xuehe; Jiang, Hong; Liu, Jinxun; Zhang, Xiuying; Jin, Jiaxin; Zhu, Qiuan; Zhang, Zhen; Peng, Changhui

    2016-01-01

    Over the past 100 years, human activity has greatly changed the rate of atmospheric N (nitrogen) deposition in terrestrial ecosystems, resulting in N saturation in some regions of the world. The contribution of N saturation to the global carbon budget remains uncertain due to the complicated nature of C-N (carbon-nitrogen) interactions and diverse geography. Although N deposition is included in most terrestrial ecosystem models, the effect of N saturation is frequently overlooked. In this study, the IBIS (Integrated BIosphere Simulator) was used to simulate the global-scale effects of N saturation during the period 1961–2009. The results of this model indicate that N saturation reduced global NPP (Net Primary Productivity) and NEP (Net Ecosystem Productivity) by 0.26 and 0.03 Pg C yr−1, respectively. The negative effects of N saturation on carbon sequestration occurred primarily in temperate forests and grasslands. In response to elevated CO2 levels, global N turnover slowed due to increased biomass growth, resulting in a decline in soil mineral N. These changes in N cycling reduced the impact of N saturation on the global carbon budget. However, elevated N deposition in certain regions may further alter N saturation and C-N coupling.

  14. Correlation between Oxygen Saturation and Hemoglobin and Hematokrit Levels in Tetralogy of Fallot Patients

    Directory of Open Access Journals (Sweden)

    Farhatul Inayah Adiputri

    2016-03-01

    Full Text Available Background: Hemoglobin and hematocrit levels increase in Tetralogy of Fallot (TOF but the oxygen saturation declines. Reduced hemoglobin in circulating blood as a parameter of cyanosis does not indicate rising hemoglobin due to the ‘not-working’ hemoglobins that affect the oxygen saturation. Increasing hematocrit is the result of secondary erythrocytosis caused by declining oxygen level in blood, which is related to the oxygen saturation. This study was conducted to find the correlation between oxygen saturation and hemoglobin and hematocrite levels in TOF patients. Methods: This study was undertaken at Dr. Hasan Sadikin General Hospital in the period of January 2011 to December 2012 using the cross-sectional analytic method with total sampling technique. Inclusion criteria were medical records of TOF patients diagnosed based on echocardiography that included data on oxygen saturation, hemoglobin, and hematocrite. Exclusion criteria was the history of red blood transfusion. Results: Thirty medical records of TOF patiens from Dr. Hasan Sadikin General Hospital Bandung were included in this study. Due to skewed data distribution, Spearman correlation test was used to analyze the data. There was a significant negative correlation between oxygen saturation and hematocrit level (r= -0.412; p=0.024 and insignificant correlation between oxygen saturation and hemoglobin (r=-0.329; p= 0.076. Conclusions: There is a weak negative correlation between oxygen saturation and hematocrite levels

  15. Effect of partial saturation of bonded neo magnet on the automotive accessory motor

    Science.gov (United States)

    Sheth, Nimitkumar K.; Angara, Raghu C. S. Babu

    2017-05-01

    In this paper the effects of using a partially magnetized bonded neo (NdFeB) magnet in an automotive accessory motor are presented. The potential reason for partial saturation of the bonded neo magnet is explained and a simple method to ensure saturation of the magnet is discussed. A magnetizing fixture design using the 2-D Finite element analysis (FEA) is presented. The motor performance at various magnet saturation levels has been estimated using the 2-D FEA. Details of the thermal demagnetization test adopted by the automotive industry is also discussed and results of the motor performance for four saturation levels are detailed. These results indicate that the effect of demagnetization is more adverse in a motor with partially saturated magnets.

  16. Sliding mode control design of a ship steering autopilot with input saturation

    Directory of Open Access Journals (Sweden)

    Muhammad Ejaz

    2017-05-01

    Full Text Available In this article, a sliding mode control scheme for the autopilot system of a ship is presented, which also incorporates actuator saturation. Under the designed controller, the actuator doesn’t enter its saturation mode. Meanwhile, the stability of the closed-loop system can be guaranteed for the ship with input saturation. Fuzzy logic is used to handle gain to avoid the chattering effect, and it is compared with saturation function. The control system for the mathematical model of a scale replica of an “Esso Osaka” tanker is simulated in time domain for the effectiveness of the controller. The simulation results show that the proposed controller is more efficient as compared to the traditional and saturation function methods.

  17. Input-output linearizing tracking control of induction machine with the included magnetic saturation

    DEFF Research Database (Denmark)

    Dolinar, Drago; Ljusev, Petar; Stumberger, Gorazd

    2003-01-01

    The tracking control design of an induction motor, based on input-output linearisation with magnetic saturation included is addressed. The magnetic saturation is represented by a nonlinear magnetising curve for the iron core and is used in the control, the observer of the state variables......, and in the load torque estimator. An input-output linearising control is used to achieve better tracking performances. It is based on the mixed 'stator current - rotor flux linkage' induction motor model with magnetic saturation considered in the stationary reference frame. Experimental results show...... that the proposed input-output linearising tracking control with saturation included behaves considerably better than the one without saturation, and that it introduces smaller position and speed errors, and better motor stiffness on account of the increased computational complexity....

  18. Impact of magnetic saturation on the input-output linearising tracking control of an induction motor

    DEFF Research Database (Denmark)

    Dolinar, Drago; Ljusev, Petar; Stumberger, Gorazd

    2004-01-01

    This paper deals with the tracking control design of an induction motor, based on input-output linearization with magnetic saturation included. Magnetic saturation is represented by the nonlinear magnetizing curve of the iron core and is used in the control design, the observer of state variables......, and in the load torque estimator. An input-output linearising control is used to achieve better tracking performances of the drive. It is based on the mixed ”stator current - rotor flux linkage” induction motor model with magnetic saturation considered in the stationary reference frame. Experimental results show...... that the proposed input-output linearising tracking control with the included saturation behaves considerably better than the one without saturation, and that it introduces smaller position and speed errors, and better motor stiffness on account of the increased computational complexity....

  19. The microphotometric determination of the variability of oxygen saturation of erythrocytes lying within rouleaux.

    Science.gov (United States)

    Lubbers, D W; Grisar, H; Gayeski, T E

    1987-01-01

    It was found that by using nonlinear multicomponent analysis with the spectra of oxygenated and deoxygenated haemoglobin as basic spectra the mean O2 saturation of 2 to 3 red cells lying in a rouleau could be determined with an accuracy of 0.5 - 1.0%. At the same PO2 and PCO2 distinct differences in O2 saturation were found in different red cells; for 50% of the saturation values the differences were in the range +/- 1.5%, for 30% of the values, the differences were in the range of +/- 3% and 15% lay in the range of +/- 4.5%. Only 5% of saturation differences were larger than 4.6%. These differences are so large that they have to be considered in calculations of the PO2 from O2 saturation measurements.

  20. Sensorless position estimation and control of permanent-magnet synchronous motors using a saturation model

    Science.gov (United States)

    Kassem Jebai, Al; Malrait, François; Martin, Philippe; Rouchon, Pierre

    2016-03-01

    Sensorless control of permanent-magnet synchronous motors at low velocity remains a challenging task. A now well-established method consists of injecting a high-frequency signal and using the rotor saliency, both geometric and magnetic-saturation induced. This paper proposes a clear and original analysis based on second-order averaging of how to recover the position information from signal injection; this analysis blends well with a general model of magnetic saturation. It also proposes a simple parametric model of the saturated motor, based on an energy function which simply encompasses saturation and cross-saturation effects. Experimental results on a surface-mounted motor and an interior magnet motor illustrate the relevance of the approach.

  1. Predicting colloid transport through saturated porous media: A critical review

    Science.gov (United States)

    Molnar, Ian L.; Johnson, William P.; Gerhard, Jason I.; Willson, Clinton S.; O'Carroll, Denis M.

    2015-09-01

    Understanding and predicting colloid transport and retention in water-saturated porous media is important for the protection of human and ecological health. Early applications of colloid transport research before the 1990s included the removal of pathogens in granular drinking water filters. Since then, interest has expanded significantly to include such areas as source zone protection of drinking water systems and injection of nanometals for contaminated site remediation. This review summarizes predictive tools for colloid transport from the pore to field scales. First, we review experimental breakthrough and retention of colloids under favorable and unfavorable colloid/collector interactions (i.e., no significant and significant colloid-surface repulsion, respectively). Second, we review the continuum-scale modeling strategies used to describe observed transport behavior. Third, we review the following two components of colloid filtration theory: (i) mechanistic force/torque balance models of pore-scale colloid trajectories and (ii) approximating correlation equations used to predict colloid retention. The successes and limitations of these approaches for favorable conditions are summarized, as are recent developments to predict colloid retention under the unfavorable conditions particularly relevant to environmental applications. Fourth, we summarize the influences of physical and chemical heterogeneities on colloid transport and avenues for their prediction. Fifth, we review the upscaling of mechanistic model results to rate constants for use in continuum models of colloid behavior at the column and field scales. Overall, this paper clarifies the foundation for existing knowledge of colloid transport and retention, features recent advances in the field, critically assesses where existing approaches are successful and the limits of their application, and highlights outstanding challenges and future research opportunities. These challenges and opportunities

  2. 1

    Science.gov (United States)

    Marquardt, Drew; Heberle, Frederick A; Miti, Tatiana; Eicher, Barbara; London, Erwin; Katsaras, John; Pabst, Georg

    2017-04-18

    We measured the transbilayer diffusion of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in large unilamellar vesicles, in both the gel (L β' ) and fluid (L α ) phases. The choline resonance of headgroup-protiated DPPC exchanged into the outer leaflet of headgroup-deuterated DPPC-d13 vesicles was monitored using 1 H NMR spectroscopy, coupled with the addition of a paramagnetic shift reagent. This allowed us to distinguish between the inner and outer bilayer leaflet of DPPC, to determine the flip-flop rate as a function of temperature. Flip-flop of fluid-phase DPPC exhibited Arrhenius kinetics, from which we determined an activation energy of 122 kJ mol -1 . In gel-phase DPPC vesicles, flip-flop was not observed over the course of 250 h. Our findings are in contrast to previous studies of solid-supported bilayers, where the reported DPPC translocation rates are at least several orders of magnitude faster than those in vesicles at corresponding temperatures. We reconcile these differences by proposing a defect-mediated acceleration of lipid translocation in supported bilayers, where long-lived, submicron-sized holes resulting from incomplete surface coverage are the sites of rapid transbilayer movement.

  3. Detailed Analysis of the Surface Area and Elasticity in the Saturated 1,2-Diacylphosphatidylcholine/Cholesterol Binary Monolayer System.

    Science.gov (United States)

    Miyoshi, Tsubasa; Kato, Satoru

    2015-08-25

    The surface pressure-area (π-A) isotherms of DMPC, DPPC, and DSPC/cholesterol binary monolayers were systematically measured with great care to gain insight into the lateral molecular packing in these binary monolayer systems. The average molecular area A and the area elastic modulus C(s)⁻¹ at a given surface pressure were calculated as a function of cholesterol mole fraction x(chol). As a result, data reliable enough for the analysis of detailed phase behavior were obtained. We identified several characteristic phase regions and assigned the phase state in each region on the basis of the deviation of A(x(chol)) and C(s)⁻¹(x(chol)) from ideal additivity. We also estimated the partial molecular areas of DMPC, DPPC, DSPC, and cholesterol in the single-phase regions, where C(s)⁻¹(x(chol)) values fell on an ideal additivity curve. We found that the addition of cholesterol induces the formation of a highly condensed phase where the diacylphosphatidylcholine (diacyl PC) molecule has a surface area even smaller than that in the solid phase, irrespective of the surface pressure and the chain length of diacyl PC. Here, we call the cholesterol-induced condensed phase the CC phase. Furthermore, we demonstrated that the basic features of A(x(chol)) and C(s)⁻¹(x(chol)) profiles can be explained semiquantitatively by assuming the state of vicinity lipids surrounding sparsely distributed cholesterol molecules in the low x(chol) region as a third state of the diacyl PC molecule in addition to the states in the pure diacyl PC monolayer and in the CC phase.

  4. Relationship between oxygen saturation, gestational age, and level of oral feeding skills in preterm infants.

    Science.gov (United States)

    Yamamoto, Raquel Coube de Carvalho; Prade, Leila Sauer; Bolzan, Geovana de Paula; Weinmann, Angela Regina Maciel; Keske-Soares, Márcia

    2017-03-09

    To correlate the peripheral oxygen saturation with gestational age and the level of oral feeding skills in the introduction of oral feeding in preterm infants. This is a cross-sectional, quantitative study whose sample was composed of 169 clinically stable preterm infants. Peripheral oxygen saturation was assessed before and after introduction of oral feeding. The preterm infants were stratified into three groups based on their gestational age at birth: 26-29, 30-33, and 34-36 weeks. The preterm infants were classified into four levels according to their oral feeding skill and resistance. No differences in oxygen saturation were observed between the strata of gestational age and between the levels of oral feeding skill. Differences were observed in the groups of preterm infants aged 30-33 weeks (p=0.04) and 34-36 weeks (p=0.02) and on the level I of oral feeding skills (p=0.04) when oxygen saturation was compared at pre- and post-first oral feeding. Significant correlations (poral feeding skills (r=0.38); in Group A, between gestational age and oxygen saturation before the first oral feeding (r=0.83); in Group B, between the level of oral feeding skill and oxygen saturation before the first oral feeding (r=0.26) and between level of oral feeding skill and gestational age (r=0.26). Correlation was found for peripheral oxygen saturation when compared with gestational age and with the level of oral feeding skills.

  5. Experimental study on distributed optical fiber-based approach monitoring saturation line in levee engineering

    Science.gov (United States)

    Su, Huaizhi; Li, Hao; Kang, Yeyuan; Wen, Zhiping

    2018-02-01

    Seepage is one of key factors which affect the levee engineering safety. The seepage danger without timely detection and rapid response may likely lead to severe accidents such as seepage failure, slope instability, and even levee break. More than 90 percent of levee break events are caused by the seepage. It is very important for seepage behavior identification to determine accurately saturation line in levee engineering. Furthermore, the location of saturation line has a major impact on slope stability in levee engineering. Considering the structure characteristics and service condition of levee engineering, the distributed optical fiber sensing technology is introduced to implement the real-time observation of saturation line in levee engineering. The distributed optical fiber temperature sensor system (DTS)-based monitoring principle of saturation line in levee engineering is investigated. An experimental platform, which consists of DTS, heating system, water-supply system, auxiliary analysis system and levee model, is designed and constructed. The monitoring experiment of saturation line in levee model is implemented on this platform. According to the experimental results, the numerical relationship between moisture content and thermal conductivity in porous medium is identified. A line heat source-based distributed optical fiber method obtaining the thermal conductivity in porous medium is developed. A DTS-based approach is proposed to monitor the saturation line in levee engineering. The embedment pattern of optical fiber for monitoring saturation line is presented.

  6. Measurement of mucosal capillary hemoglobin oxygen saturation in the colon by reflectance spectrophotometry

    Science.gov (United States)

    Friedland, Shai; Benaron, David A.; Parachikov, Ilian H.; Soetikno, Roy

    2003-06-01

    Advances in optical and computer technology have enabled the development of a device that utilizes white-light reflectance spectrophotometry to measure capillary hemoglobin saturation in intestinal mucosa during colonoscopy. Studies were performed using the colon oximeter in anesthetized animals and patients undergoing colonoscopy. Mucosal hemoglobin saturation in the normal colon (mean +/- S.D.) is 72% +/- 3.5%. In an animal model, ischemia via arterial ligation and hypoxemia via hypoxic ventilation each result in a decrease of over 40% in the mucosal saturation. In human patients with colon polyps, ischemia induced by epinephrine injection, stalk ligation using a loop, or clipping of the polyp stalk each result in a decrease of over 40% in the mucosal saturation (pmesenteric artery had a saturation of 55% in the remaining sigmoid colon, with normal values in the superior mesenteric artery territory (p<0.05). A novel device for measuring capillary hemoglobin saturation in intestinal mucosa during colonoscopy is capable of providing reproducible measurements in normal patients and clearly detects dramatic decreases in saturation with ischemic and hypoxic insults.

  7. Monitor hemoglobin concentration and oxygen saturation in living mouse tail using photoacoustic CT scanner

    Science.gov (United States)

    Liu, Bo; Kruger, Robert; Reinecke, Daniel; Stantz, Keith M.

    2010-02-01

    Purpose: The purpose of this study is to use PCT spectroscopy scanner to monitor the hemoglobin concentration and oxygen saturation change of living mouse by imaging the artery and veins in a mouse tail. Materials and Methods: One mouse tail was scanned using the PCT small animal scanner at the isosbestic wavelength (796nm) to obtain its hemoglobin concentration. Immediately after the scan, the mouse was euthanized and its blood was extracted from the heart. The true hemoglobin concentration was measured using a co-oximeter. Reconstruction correction algorithm to compensate the acoustic signal loss due to the existence of bone structure in the mouse tail was developed. After the correction, the hemoglobin concentration was calculated from the PCT images and compared with co-oximeter result. Next, one mouse were immobilized in the PCT scanner. Gas with different concentrations of oxygen was given to mouse to change the oxygen saturation. PCT tail vessel spectroscopy scans were performed 15 minutes after the introduction of gas. The oxygen saturation values were then calculated to monitor the oxygen saturation change of mouse. Results: The systematic error for hemoglobin concentration measurement was less than 5% based on preliminary analysis. Same correction technique was used for oxygen saturation calculation. After correction, the oxygen saturation level change matches the oxygen volume ratio change of the introduced gas. Conclusion: This living mouse tail experiment has shown that NIR PCT-spectroscopy can be used to monitor the oxygen saturation status in living small animals.

  8. Asymptotic structural properties of quasi-random saturated structures of RNA

    Science.gov (United States)

    2013-01-01

    Background RNA folding depends on the distribution of kinetic traps in the landscape of all secondary structures. Kinetic traps in the Nussinov energy model are precisely those secondary structures that are saturated, meaning that no base pair can be added without introducing either a pseudoknot or base triple. In previous work, we investigated asymptotic combinatorics of both random saturated structures and of quasi-random saturated structures, where the latter are constructed by a natural stochastic process. Results We prove that for quasi-random saturated structures with the uniform distribution, the asymptotic expected number of external loops is O(logn) and the asymptotic expected maximum stem length is O(logn), while under the Zipf distribution, the asymptotic expected number of external loops is O(log2n) and the asymptotic expected maximum stem length is O(logn/log logn). Conclusions Quasi-random saturated structures are generated by a stochastic greedy method, which is simple to implement. Structural features of random saturated structures appear to resemble those of quasi-random saturated structures, and the latter appear to constitute a class for which both the generation of sampled structures as well as a combinatorial investigation of structural features may be simpler to undertake. PMID:24156624

  9. Interrelation of saturated fat, trans fat, alcohol intake, and subclinical atherosclerosis.

    Science.gov (United States)

    Merchant, Anwar T; Kelemen, Linda E; de Koning, Lawrence; Lonn, Eva; Vuksan, Vlad; Jacobs, Ruby; Davis, Bonnie; Teo, Koon K; Yusuf, Salim; Anand, Sonia S

    2008-01-01

    Intake of saturated fat, trans fat, and alcohol alter cardiovascular disease risk, but their effect on subclinical atherosclerosis remains understudied. The objective was to examine and quantify the interrelation of saturated fat, trans fat, alcohol intake, and mean carotid artery intimal medial thickness (IMT). We conducted a population-based, cross-sectional study among 620 persons of Aboriginal, South Asian, Chinese, or European origin aged 35-75 y, who had lived in Canada for >or=5 y. Mean IMT was calculated from 6 well-defined segments of the right and left carotid arteries with standardized B-mode ultrasound, and saturated fat, trans fat, and alcohol intakes were measured with validated food-frequency questionnaires. For every 10-g/d increase in saturated fat intake, IMT was 0.03 mm higher (P=0.01) after multivariate adjustment. A 1-g/d higher intake of trans fat was associated with a 0.03-mm higher IMT (P=0.02) after multivariate adjustment. The ratio of polyunsaturated to saturated fat (P:S) was inversely associated with IMT after multivariate adjustment (change in IMT: -0.06 mm; Ptrans fat intakes were independently associated with IMT thickness (change in IMT: 0.03 mm; Pfat intakes were unrelated to IMT. The relation between saturated fat intake and IMT strengthened (beta=0.0066, Ptrans fats are independently associated with increased subclinical atherosclerosis, and alcohol intake may attenuate the relation between saturated fat and subclinical atherosclerosis.

  10. The monitoring of venous saturations of oxygen in children with congenitally malformed hearts.

    Science.gov (United States)

    Martin, Jeff; Shekerdemian, Lara S

    2009-02-01

    Mixed venous saturation of oxygen has for some time been used as a tool to assess the adequacy of systemic delivery of oxygen in intensive care. In the post-operative child with cardiac disease, it is increasingly being used to assess adequacy of cardiac output. In many of these patients, true sampling of mixed venous saturation of oxygen is not possible due to the infrequent use of pulmonary arterial catheters, or the presence of intra-cardiac left to right shunting leading to mixing of systemic and pulmonary venous blood. The use of saturation of oxygen in the central venous blood as a surrogate for mixed venous saturation of oxygen has been widely investigated in adults, but its use remains controversial. In this review, we discuss the theory behind the use of mixed venous saturation of oxygen in evaluating cardiac output, the problems pertinent to those patients with congenitally malformed hearts, and explore the evidence for central venous saturation of oxygen as a surrogate for mixed venous saturation of oxygen, and its use as a therapeutic target to improve outcomes in this population of patients.

  11. Determination of saturated aliphatic hydrocarbons in vegetable oils

    Directory of Open Access Journals (Sweden)

    Gómez-Coca, R. B.

    2016-06-01

    Full Text Available The aim of this work is to inform about the development of a simple and reliable off-line method for the determination of saturated hydrocarbons (SH in vegetable oils. SH can be used as markers for fuel or for mineral oil contamination in edible oils and fats. The method consists of the isolation of the fraction by LC on deactivated silver-silica gel and subsequent on-column GC-FID analysis. This stationary phase was prepared avoiding any kind of activation. The method was developed and validated through the participation in both a proficiency test organized by the Joint Research Centre of the European Commission, and a collaborative trial carried out with trained Spanish laboratories according to the standard ISO 5725. Results showed acceptable repeatability and reproducibility values, and Horrat index, being this protocol in use with satisfactory results ever since. The method’s LOQ is 15 mg.kg–1 and its LOD 5 mg.kg–1, which make it suitable to quantify the 50 mg.kg–1 limit established by the EU, and to detect mineral oil content within the 10–500 mg.kg–1 range. Although other procedures with lower LOD have been developed throughout the years, the use of just regular laboratory equipment such as GC-FID makes the proposed method appropriate for application on a routine basis.El objetivo de este trabajo es el de dar cuenta del desarrollo de un método sencillo y fiable para la determinación de hidrocarburos saturados (HS en aceites vegetales. Los HS pueden utilizarse como marcadores de contaminación de aceites y grasas comestibles con fuel-oil y aceites minerales El procedimiento consiste en el aislamiento de la fracción correspondiente por cromatografía en columna de gel de sílice argentada sin activar y posterior análisis mediante GC (on-column-FID. El método se desarrolló y validó mediante la participación en una prueba de competencia organizada por el Joint Research Centre de la Comisión Europea, además de con un

  12. Saturated Monoglyceride Polymorphism and Gel Formation of Biodiesel Blends

    Energy Technology Data Exchange (ETDEWEB)

    Chupka, Gina; Fouts, Lisa; McCormick, Robert

    2015-11-13

    Crystallization or gel formation of normal paraffins in diesel fuel under cold weather conditions leading to fuel filter clogging is a common problem. Cold weather operability of biodiesel (B100) and blends with diesel fuel presents additional complexity because of the presence of saturated monoglycerides (SMGs) and other relatively polar species. Currently, the cloud point measurement (a measure of when the first component crystallizes out of solution) is used to define the lowest temperature at which the fuel can be used without causing cold weather issues. While filter plugging issues have declined, there still remain intermittent unexpected problems above the cloud point for biodiesel blends. Development of a fundamental understanding of how minor components in biodiesel crystallize, gel, and transform is needed in order to prevent these unexpected issues. We have found that SMGs, a low level impurity present in B100 from the production process, can crystallize out of solution and undergo a solvent-mediated polymorphic phase transformation to a more stable, less soluble form. This causes them to persist at temperatures above the cloud point once they have some out of solution. Additionally, we have found that SMGs can cause other more soluble, lower melting point minor components in the B100 to co-crystallize and come out of solution. Monoolein, another minor component from the production process is an unsaturated monoglyceride with a much lower melting point and higher solubility than SMGs. It is able to form a co-crystal with the SMGs and is found together with the SMGs on plugged filters we have analyzed in our laboratory. An observation of isolated crystals in the lab led us to believe that the SMGs may also be forming a gel-like network with components of the B100 and diesel fuel. During filtration experiments, we have noted that in some cases a solid layer of crystals forms and blocks the filter completely, while in other cases this does not occur

  13. Using noble gas tracers to estimate residual CO2 saturation in the field: results from the CO2CRC Otway residual saturation and dissolution test

    Science.gov (United States)

    LaForce, T.; Ennis-King, J.; Paterson, L.

    2013-12-01

    Residual CO2 saturation is a critically important parameter in CO2 storage as it can have a large impact on the available secure storage volume and post-injection CO2 migration. A suite of single-well tests to measure residual trapping was conducted at the Otway test site in Victoria, Australia during 2011. One or more of these tests could be conducted at a prospective CO2 storage site before large-scale injection. The test involved injection of 150 tonnes of pure carbon dioxide followed by 454 tonnes of CO2-saturated formation water to drive the carbon dioxide to residual saturation. This work presents a brief overview of the full test sequence, followed by the analysis and interpretation of the tests using noble gas tracers. Prior to CO2 injection krypton (Kr) and xenon (Xe) tracers were injected and back-produced to characterise the aquifer under single-phase conditions. After CO2 had been driven to residual the two tracers were injected and produced again. The noble gases act as non-partitioning aqueous-phase tracers in the undisturbed aquifer and as partitioning tracers in the presence of residual CO2. To estimate residual saturation from the tracer test data a one-dimensional radial model of the near-well region is used. In the model there are only two independent parameters: the apparent dispersivity of each tracer and the residual CO2 saturation. Independent analysis of the Kr and Xe tracer production curves gives the same estimate of residual saturation to within the accuracy of the method. Furthermore the residual from the noble gas tracer tests is consistent with other measurements in the sequence of tests.

  14. Comparison of isocaloric very low carbohydrate/high saturated fat and high carbohydrate/low saturated fat diets on body composition and cardiovascular risk

    OpenAIRE

    James Anthony P; Keogh Jennifer B; Foster Paul R; Noakes Manny; Mamo John C; Clifton Peter M

    2006-01-01

    Abstract Background It is speculated that high saturated fat very low carbohydrate diets (VLCARB) have adverse effects on cardiovascular risk but evidence for this in controlled studies is lacking. The objective of this study was to compare, under isocaloric conditions, the effects of a VLCARB to 2 low saturated fat high carbohydrate diets on body composition and cardiovascular risk. Methods Eighty three subjects, 48 ± 8 y, total cholesterol 5.9 ± 1.0 mmol/L, BMI 33 ± 3 kg/m2 were randomly al...

  15. Strength and Biot's coefficient for high-porosity oil- or water-saturated chalk

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling

    considerations for the size of the drilling window and the magnitude of the lateral stress involve the Biot coefficient. Additionally, the fluid effect of oil-saturated chalk behaving much stronger than water-saturated chalk affects geomechanical considerations related to e.g. water injection into a reservoir...... during hydrostatic loading. The hypothesis is that the Biot coefficient and the theory of poroelasticity may cover the fluid effect by including the increased fluid bulk modulus from oil to water. A high number of test results for both oil- and water-saturated high-porosity outcrop chalk show correlation...

  16. Cracking and reformation of saturated hydrocarbons by ultrasound in the presence of water

    Science.gov (United States)

    Prudhomme, M. R. O.; Lefort, J.

    1974-01-01

    The exposure of saturated hydrocarbons to ultrasound (800 kHz, 6 W/sq cm) in the presence of water results in: (1) cleavage of the carbon chain, producing saturated and unsaturated hydrocarbons with a lower number of carbons than the initial hydrocarbon (cracking); and (2) recombination after cleavage, producing saturated and unsaturated hydrocarbons with a higher number of carbons than the initial hydrocarbon (reformation). The addition of argon facilitates these phenomena. The effects are attributed to a homolytic (radical) mechanism occurring within the cavitation bubbles under the effects of microsparks.

  17. Very low saturation densities in strained InGaAs/AlGaAs multiple quantum wells

    OpenAIRE

    HEGARTY, JOHN

    1994-01-01

    PUBLISHED The saturation of excitonic absorption in strained InGaAs/AlGaAs quantum wells is systematically measured as a function of strain. By comparison with an unstrained GaAs/AlGaAs quantum well sample a reduction by a factor of up to 9 in the saturation carrier density is observed in strained samples with indium concentrations of 10% `and 15%. Very low saturation densities, as low as 0.82X 1017 cmm3, are reported for the InGaAs/AlGaAs quantum wells with an indium concentra...

  18. Improved dq-Axes Model of PMSM Considering Airgap Flux Harmonics and Saturation

    DEFF Research Database (Denmark)

    Fasil, Muhammed; Antaloae, Ciprian; Mijatovic, Nenad

    2016-01-01

    In this work, the classical linear model of a permanent magnet synchronous motor (PMSM) is modified by adding d and q-axes harmonic inductances so that the modified model can consider non-linearities present in an interior permanent magnet (IPM) motor. Further, a method has been presented to assess...... the effect of saturation and cross-saturation on constant torque curves of PMSM. Two IPM motors with two different rotor topologies and different specifications are designed to evaluate the effect of saturation on synchronous and harmonic inductances, and on operating points of the machines...

  19. Phase behavior of lipid monolayers containing DPPC and cholesterol analogs.

    Science.gov (United States)

    Stottrup, Benjamin L; Keller, Sarah L

    2006-05-01

    We investigate the miscibility phase behavior of lipid monolayers containing a wide variety of sterols. Six of the sterols satisfy a definition from an earlier study of "membrane-active sterols" in bilayers (cholesterol, epicholesterol, lathosterol, dihydrocholesterol, ergosterol, and desmosterol), and six do not (25-hydroxycholesterol, lanosterol, androstenolone, coprostanol, cholestane, and cholestenone). We find that monolayers containing dipalmitoyl phosphatidylcholine mixed with membrane-active sterols generally produce phase diagrams containing two distinct regions of immiscible liquid phases, whereas those with membrane-inactive sterols generally do not. This observation establishes a correlation between lipid monolayers and bilayers. It also demonstrates that the ability to form two regions of immiscibility in monolayers is not one of the biophysical attributes that explains cholesterol's predominance in animal cell membranes. Furthermore, we find unusual phase behavior for dipalmitoyl phosphatidylcholine monolayers containing 25-hydroxycholesterol, which produce both an upper and a lower miscibility transition. The lower transition correlates with a sharp change of slope in the pressure-area isotherm.

  20. Global Asymptotic Stability of the Classical PID Controller by Considering Saturation Effects in Industrial Robots

    Directory of Open Access Journals (Sweden)

    Antonio Yarza

    2011-09-01

    Full Text Available An unsolved ancient problem in position control of robot manipulators is to find a stability analysis that proves global asymptotic stability of the classical PID control in closed loop with robot manipulators. The practical evidence suggests that in fact the classical PID in industrial robots is a global regulator. The main goal of the present paper is theoretically to show why in the practice such a fact is achieved. We show that considering the natural saturations of every control stage in practical robots, the classical PID becomes a type of saturated nonlinear PID controller. In this work such a nonlinear PID controller with bounded torques for robot manipulators is proposed. This controller, unlike other saturated nonlinear PID controllers previously proposed, uses a single saturation for the three terms of the controller. Global asymptotical stability is proved via Lyapunov stability theory. Experimental results are presented in order to observe the performance of the proposed controller.

  1. Biological multi-rogue waves in discrete nonlinear Schrödinger equation with saturable nonlinearities

    Energy Technology Data Exchange (ETDEWEB)

    Tchinang Tchameu, J.D., E-mail: jtchinang@gmail.com; Togueu Motcheyo, A.B., E-mail: abtogueu@yahoo.fr; Tchawoua, C., E-mail: ctchawa@yahoo.fr

    2016-09-07

    The discrete multi-rogue waves (DMRW) as solution of the discrete nonlinear Schrödinger (DNLS) equation with saturable nonlinearities is studied numerically. These biological rogue waves represent the complex probability amplitude of finding an amide-I vibrational quantum at a site. We observe that the growth in the higher order saturable nonlinearity implies the formation of DMRW including an increase in the short-living DMRW and a decrease in amplitude of the long-living DMRW. - Highlights: • Discrete Multi-Rogue Waves (DMRW), representing the localization of vibrational energy in protein chain, are found numerically. • The higher order saturable nonlinearity of DNLS promotes the increase in the short-living RW. • The higher order saturable nonlinearity of DNLS promotes the decrease in amplitude of the long-living RW.

  2. Saturation overland flow estimated by TOPMODEL for the conterminous United States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This 5-kilometer resolution raster (grid) dataset for the conterminous United States represents the average percentage of saturation overland flow in total...

  3. Effects of Salmeterol on Sleeping Oxygen Saturation in Chronic Obstructive Pulmonary Disease

    National Research Council Canada - National Science Library

    Ryan, Silke; Doherty, Liam S; Rock, Clare; Nolan, Geraldine M; McNicholas, Walter T

    2010-01-01

    ...) on these disturbances are unclear. Objectives: The aim of the study was to assess the effect of inhaled salmeterol on nocturnal sleeping arterial oxygen saturation (SaO ) and sleep quality. Methods...

  4. Statistical optimization of effective parameters on saturation magnetization of nanomagnetite particles

    Science.gov (United States)

    Ramimoghadam, Donya; Bagheri, Samira; Yousefi, Amin Termeh; Abd Hamid, Sharifah Bee

    2015-11-01

    In this study, nanomagnetite particles have been successfully prepared via the coprecipitation method. The effect of the key explanatory variables on the saturation magnetization of synthetic nanomagnetite particles was investigated using the response surface methodology (RSM). The correlation of the involved parameters with the growth process was examined by employing the central composite design method through designating set up experiments that will determine the interaction of the variables. The vibrating sample magnetometer (VSM) was used to confirm the statistical analysis. Furthermore, the regression analysis monitors the priority of the variables' influence on the saturation magnetization of nanomagnetite particles by developing the statistical model of the saturation magnetization. According to the investigated model, the highest interaction of variable belongs to the pH and temperature with the optimized condition of 9-11, and 75-85 °C, respectively. The response obtained by VSM suggests that the saturation magnetization of nanomagnetite particles can be controlled by restricting the effective parameters.

  5. Transferrin saturation ratio and risk of total and cardiovascular mortality in the general population.

    LENUS (Irish Health Repository)

    Stack, A G

    2014-08-01

    The transferrin saturation (TSAT) ratio is a commonly used indicator of iron deficiency and iron overload in clinical practice but precise relationships with total and cardiovascular mortality are unclear.

  6. Transport and Deposition of Suspended Soil-Colloids in Saturated Sand Columns

    DEFF Research Database (Denmark)

    Sharma, Anu; Kawamoto, Ken; Møldrup, Per

    2011-01-01

    a red‐yellow soil from Okinawa, Japan. Different concentrations of suspended‐soil colloids (with diameter water‐saturated columns repacked with either Narita (mean diameter D50 = 0.64 mm) or Toyoura (mean diameter D50 = 0...

  7. Changes in retinal oxygen saturation after intravitreal aflibercept in patients with diabetic macular edema

    DEFF Research Database (Denmark)

    Blindbæk, Søren Leer; Peto, Tunde; Grauslund, Jakob

    2017-01-01

    Design of study: Three months prospective interventional study. Purpose: To evaluate changes in retinal arterial and venous oxygen saturation after intravitreal aflibercept in patients with diabetic macular edema (DME). Methods: We included 17 patients with DME, central retinal thickness (CRT) >300...... the last injection. Retinal oxygen saturation was measured in 50-degree disc-centered images using the Oxymap model T1 (Oxymap, Reykjavik, Iceland). Global measures are presented as the average saturation of the four major arterioles and venules from the four quadrants. For macular measurements, we used...... the first traceable macular branches of the superior and inferior temporal arcades with a diameter >6µm. Paired t-test was used to test for differences in mean oxygen saturations from baseline to follow-up. Results: Median age and duration of diabetes were 59.5 and 2.6 years at baseline. Median HbA1c was 65...

  8. Compliance in oxygen saturation targeting in preterm infants : a systematic review

    NARCIS (Netherlands)

    van Zanten, Henriëtte A; Tan, Ratna N G B; van den Hoogen, Agnes|info:eu-repo/dai/nl/343075156; Lopriore, Enrico; te Pas, Arjan B

    2015-01-01

    UNLABELLED: During oxygen therapy in preterm infants, targeting oxygen saturation is important for avoiding hypoxaemia and hyperoxaemia, but this can be very difficult and challenging for neonatal nurses. We systematically reviewed the qualitative and quantitative studies investigating the

  9. Nitrogen dynamics in chaparral ecosystems: Limitations to the use of traditional N saturation indicators

    Science.gov (United States)

    Homyak, P. M.; Sickman, J. O.; Miller, A. E.; Schimel, J.; Melack, J. M.; Meixner, T.

    2012-12-01

    Chaparral ecosystems in California receive a wide range of N deposition (chaparral catchments are partially N saturated at N input rates of 9 kg N ha-1 yr-1, but that complete N saturation of all sinks may be difficult to reach in ecosystems that inherently leak N during seasonal transitions. We conclude that chaparral has an intrinsic capacity to export N thereby limiting the use of elevated N losses and N budgets for the assessment of N saturation. We propose that N dynamics during the winter growing season are more diagnostic of long-term ecosystem response to N deposition. Specifically, the N saturation status of chaparral catchments is best assessed by how rapidly catchments transition from N-loss to N-retention during the growing season.

  10. [Comprehensive analysis of up-conversion luminescence saturation phenomena of ErYb:oxyfluoride vitroceramics].

    Science.gov (United States)

    Chen, Xiao-bo; Song, Zeng-fu

    2005-02-01

    The saturation phenomenon of the up-conversion luminescence of erbium ytterbium co-doped oxyfluoride vitroceramics (ErYb:FOV), when excited by a 966 nm diode-laser, was investigated comprehensively in the present article. A new kind of "characteristic saturation phenomenon", which results from energy diffusion, was found, i. e. the slope of logI-logP curve, the double logarithmic variation of up-conversion luminescence intensity I upon laser power P, is increased evidently toward regular multi-photon relation with the increase of laser facula. The "typical saturation phenomenon" resulting from ground state population's exhaustion has huge influence as well, which causes these logI-logP curves to bend gradually with the increase in laser power. Interestingly, this "typical saturation phenomenon" can be decreased obviously and even vanishes when the pumping laser power density is decreased enough.

  11. The effect of dietary lipid saturation and antioxidant type on the ...

    African Journals Online (AJOL)

    uvp

    2014-08-22

    Aug 22, 2014 ... differing in origin and the degree of saturation to ruminants may then result in a ..... level effects on finishing steer performance, digestion and metabolism. ... and fatty acid profile in the rumen of sheep fed a diet containing.

  12. Fuzzy Saturated Output Feedback Tracking Control for Robot Manipulators: A Singular Perturbation Theory Based Approach

    National Research Council Canada - National Science Library

    Liu, Huashan; Hao, Kuangrong; Lai, Xiaobo

    2011-01-01

    To deal with the problem of the output feedback tracking (OFT) control with bounded torque inputs of robot manipulators, we propose a generalized fuzzy saturated OFT controller based on singular perturbation theory...

  13. Counting losses due to saturation effects of scintillation counters at high count rates

    CERN Document Server

    Hashimoto, K

    1999-01-01

    The counting statistics of a scintillation counter, with a preamplifier saturated by an overloading input, are investigated. First, the formulae for the variance and the mean number of counts, accumulated within a given gating time, are derived by considering counting-loss effects originating from the saturation and a finite resolving time of the electronic circuit. Numerical examples based on the formulae indicate that the saturation makes a positive contribution to the variance-to-mean ratio and that the contribution increases with count rate. Next the ratios are measured under high count rates when the preamplifier saturation can be observed. By fitting the present formula to the measured data, the counting-loss parameters can be evaluated. Corrections based on the parameters are made for various count rates measured in a nuclear reactor. As a result of the corrections, the linearity between count rate and reactor power can be restored.

  14. Ohmic energy confinement saturation and core toroidal rotation reversal in Alcator C-Mod plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rice, J. E.; Greenwald, M. J.; Podpaly, Y. A.; Reinke, M. L.; Hughes, J. W.; Howard, N. T.; Ma, Y.; Cziegler, I.; Ennever, P. C.; Ernst, D.; Fiore, C. L.; Gao, C.; Irby, J. H.; Marmar, E. S.; Porkolab, M.; Tsujii, N.; Wolfe, S. M. [Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States); Diamond, P. H. [UCSD, La Jolla, California 92903 (United States); Duval, B. P. [CRPP, EPFL, Lausanne 1015 (Switzerland)

    2012-05-15

    Ohmic energy confinement saturation is found to be closely related to core toroidal rotation reversals in Alcator C-Mod tokamak plasmas. Rotation reversals occur at a critical density, depending on the plasma current and toroidal magnetic field, which coincides with the density separating the linear Ohmic confinement regime from the saturated Ohmic confinement regime. The rotation is directed co-current at low density and abruptly changes direction to counter-current when the energy confinement saturates as the density is increased. Since there is a bifurcation in the direction of the rotation at this critical density, toroidal rotation reversal is a very sensitive indicator in the determination of the regime change. The reversal and confinement saturation results can be unified, since these processes occur in a particular range of the collisionality.

  15. Opening-mode cracking in asphalt pavements : crack initiation and saturation.

    Science.gov (United States)

    2009-12-01

    This paper investigates the crack initiation and saturation for opening-mode cracking. Using elastic governing equations : and a weak form stress boundary condition, we derive an explicit solution of elastic fields in the surface course and : obtain ...

  16. Multi-input robust saturation controller for uncertain linear time-invariant systems

    Science.gov (United States)

    Lim, Chae-Wook

    2007-03-01

    A robust saturation controller for the linear time-invariant (LTI) system involving both a control input's saturation and structured real parameter uncertainties was proposed in [C.W. Lim, Y. J. Park, S.J. Moon, Robust saturation controller for linear time-invariant system with structured real parameter uncertainties, Journal of Sound and Vibration 294 (1-2) (2006) 1-14]. This controller can also be applicable to the multi-input case. In this paper, the robust saturation controller is extended to the uncertain LTI system with multi-input and designed by introducing additional subsidiary setting parameters for each control input. An example is presented to show its application to multi-input uncertain LTI systems.

  17. Insights to emitter saturation current densities of boron implanted samples based on defects simulations

    NARCIS (Netherlands)

    Mok, K.R.C.; Naber, R.C.G.; Nanver, L.K.

    2012-01-01

    Emitter saturation current densities, Joe have been investigated with different boron implantation dose and annealing conditions. The higher thermal budgets used here are shown experimentally to improve Joe, implying more complete defect dissolution. Simulations show that significant degradation in

  18. Oxidative stabilization of mixed mayonnaises made with linseed oil and saturated medium-chain triglyceride oil

    NARCIS (Netherlands)

    Raudsepp, P.; Brüggemann, D.A.; Lenferink, Aufrid T.M.; Otto, Cornelis; Andersen, M.L.

    2014-01-01

    Mayonnaises, made with either saturated medium chain triglyceride (MCT) oil or unsaturated purified linseed oil (LSO), were mixed. Raman confocal microspectrometry demonstrated that lipid droplets in mixed mayonnaise remained intact containing either MCT oil or LSO. Peroxide formation during storage

  19. Fate and transport of viruses and colloids in saturated and unsaturated porous media

    NARCIS (Netherlands)

    Torkzaban, S.

    2007-01-01

    The fundamental mechanisms involved in fate and transport of colloidal particles (viruses and latex microspheres) in saturated and unsaturated porous media were systematically examined. Two different bacteriophages were used as surrogate for pathogenic viruses to investigate the effects of various

  20. Dietary hydroxypropyl methylcellulose increases excretion of saturated and trans fats by hamsters fed fast food diets

    Science.gov (United States)

    The hypocholesterolemic and hypoglycemic effects of hydroxypropyl methylcellulose (HPMC), a semisynthetic nonfermentable soluble dietary fiber, are well established. However, effects of HPMC on dietary saturated fatty acids and trans fatty acids are largely unknown. This study investigated the eff...

  1. Theoretical saturation in qualitative research: an experience report in interview with schoolchildren

    Directory of Open Access Journals (Sweden)

    Luciana de Cassia Nunes Nascimento

    Full Text Available ABSTRACT Objective: report the experience of applying the theoretical data saturation technique in qualitative research with schoolchildren. Method: critical reading of primary sources and compilation of raw data, followed by thematic grouping through colorimetric codification and allocation of themes/types of statements in charts to find theoretical saturation for each grouping. Results: colorimetric codification occurred according to previously established themes: bodily hydration; physical activities and play; handling of sickle-cell disease; feeding and clothing. On the eleventh interview, it was possible to reach the theoretical saturation of themes, with four additional interviews being performed. Conclusion: this experience report enabled the description of the five sequential steps for identification of theoretical data saturation in qualitative research conducted with schoolchildren.

  2. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacou, P A [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Shafqat, K [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Pal, S K [St Andrew' s Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, CM1 7ET (United Kingdom)

    2007-10-15

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO{sub 2}) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO{sub 2}) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO{sub 2} sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures

  3. Effects of target and distractor saturations on the cognitive performance of an integrated display interface

    Science.gov (United States)

    Xue, Chengqi; Li, Jing; Wang, Haiyan; Niu, Yafeng

    2015-01-01

    Color coding is often used to enhance decision quality in complex man-machine interfaces of integrated display systems. However, people are easily distracted by irrelevant colors and by the numerous data points and complex structures in the interface. Although an increasing number of studies are seriously focusing on the problem of achieving efficient color coding, few are able to determine the effects of target and distractor saturations on cognitive performance. To study the performances of target colors among distractors, a systematic experiment is conducted to assess the influence of high and low saturated targets on cognitive performance, and the affecting extent of different saturated distractors of homogeneous colors on targets. According to the analysis of the reaction time through the non-parametric statistical method, a calculation method of the cognitive performance of each color is proposed. Based on the calculation of the color differences and the accumulation of the reaction times, it is shown that with the different saturated distractors of homogeneous colors, the high saturated yellow targets perform better than the low saturated ones, and the green and blue targets have moderate performances. When searching for a singleton target placed on a black background, the color difference between the target and the distractor should be more than 20Δ E*ab units in the yellow saturation coding, whereas the color difference should be more than 40Δ E*ab units in the blue and green saturation coding. In addition, as regards saturation coding, the influence of the color difference between the target and the background on cognitive performance is greater than that of the color difference between the target and the distractor. Seemingly, the hue attribute determines whether the saturation difference between the target and the distractor affects the cognitive performance. Based on the experimental results, the simulation design of the instrument dials in a flight

  4. The cascaded amplifier and saturable absorber (CASA) all-optical switch

    DEFF Research Database (Denmark)

    Hilliger, E.; Berger, J.; Weber, H. G.

    2001-01-01

    The cascaded amplifier and saturable absorber is presented as a new all-optical switching scheme for optical signal processing applications. First demultiplexing experiments demonstrate the principle of operation of this scheme.......The cascaded amplifier and saturable absorber is presented as a new all-optical switching scheme for optical signal processing applications. First demultiplexing experiments demonstrate the principle of operation of this scheme....

  5. Pump-To-Signal Intensity Modulation Transfer Characteristics in FOPAs: Modulation Frequency and Saturation Effect

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Cristofori, Valentina; Lund-Hansen, Toke

    2012-01-01

    This paper reports a comprehensive study of pump- to-signal intensity modulation transfer (IMT) in single-pump fiber optic parametric amplifiers (FOPAs). In particular, the IMT is studied for the first time for high-frequency fluctuations of the pump as well as in the saturated gain regime. The IMT......% in the gain saturation regime with respect to the linear gain operation. Experimental results confirm the validity of the numerical study....

  6. A second order model of noise in saturated semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Öhman, Filip; Tromborg, Bjarne; Mørk, Jesper

    2005-01-01

    We have developed a second order model of spontaneous emission noise in semiconductor optical amplifiers (SOAs). The resulting noise distributions agree well with statistical simulations and explain the measured redistribution of noise in saturated SOAs.......We have developed a second order model of spontaneous emission noise in semiconductor optical amplifiers (SOAs). The resulting noise distributions agree well with statistical simulations and explain the measured redistribution of noise in saturated SOAs....

  7. The UK food retail ‘race for space’ and market saturation:a contemporary review

    OpenAIRE

    Wood, SM; McCarthy, D

    2014-01-01

    This conceptual review paper explores food retail space saturation in the UK in the light of an apparent recent peak of store space growth, an inferred decline of the hypermarket format, and, in particular, the stagnation and subsequent deterioration in performance of the UK market leader, Tesco. Despite saturation being widely discussed by retail executives and analysts, the last significant academic work in this area occurred in the mid-1990s. In this paper, we develop an understanding of r...

  8. State-Feedback Control for Fractional-Order Nonlinear Systems Subject to Input Saturation

    Directory of Open Access Journals (Sweden)

    Junhai Luo

    2014-01-01

    Full Text Available We give a state-feedback control method for fractional-order nonlinear systems subject to input saturation. First, a sufficient condition is derived for the asymptotical stability of a class of fractional-order nonlinear systems. Then based on Gronwall-Bellman lemma and a sector bounded condition of the saturation function, a linear state-feed back controller is designed. Finally, two simulation examples are presented to show the validity of the proposed method.

  9. Fuzzy Saturated Output Feedback Tracking Control for Robot Manipulators: A Singular Perturbation Theory Based Approach

    OpenAIRE

    Huashan Liu; Kuangrong Hao; Xiaobo Lai

    2011-01-01

    To deal with the problem of the output feedback tracking (OFT) control with bounded torque inputs of robot manipulators, we propose a generalized fuzzy saturated OFT controller based on singular perturbation theory. First, considering the fact that the output toque of joint actuators is limited, a general expression for a class of saturation functions is given to be applied in the control law. Second, to carry out the whole closed‐loop control with only position measurements, linear and...

  10. Biological multi-rogue waves in discrete nonlinear Schrödinger equation with saturable nonlinearities

    Science.gov (United States)

    Tchinang Tchameu, J. D.; Togueu Motcheyo, A. B.; Tchawoua, C.

    2016-09-01

    The discrete multi-rogue waves (DMRW) as solution of the discrete nonlinear Schrödinger (DNLS) equation with saturable nonlinearities is studied numerically. These biological rogue waves represent the complex probability amplitude of finding an amide-I vibrational quantum at a site. We observe that the growth in the higher order saturable nonlinearity implies the formation of DMRW including an increase in the short-living DMRW and a decrease in amplitude of the long-living DMRW.

  11. Continous monitoring of central venous oxygen saturation in children and infants.

    Science.gov (United States)

    Vidmar, Ivan

    2010-01-01

    Maintenance of adequate tissue oxygenation is an important task in intensive care units. There are many variables which are measured for this purpose. Central venous oxygen saturation (ScvO2) monitoring has some advantages over the mixed venous oxygen saturation (SvO2) monitoring in children and infants as there is no need to insert a pulmonary catheter. The clinical usefulness seems promising.

  12. Angptl4 Protects against Severe Proinflammatory Effects of Saturated Fat by Inhibiting Fatty Acid Uptake into Mesenteric Lymph Node Macrophages

    NARCIS (Netherlands)

    Lichtenstein, L.L.; Mattijssen, F.B.J.; Wit, de N.J.W.; Georgiadi, A.; Hooiveld, G.J.E.J.; Meer, van der R.; He, Y.; Qi, L.; Köster, A.; Tamsma, J.T.; Tan, N.S.; Müller, M.R.; Kersten, A.H.

    2010-01-01

    Dietary saturated fat is linked to numerous chronic diseases, including cardiovascular disease. Here we study the role of the lipoprotein lipase inhibitor Angptl4 in the response to dietary saturated fat. Strikingly, in mice lacking Angptl4, saturated fat induces a severe and lethal phenotype

  13. Image-based calculation of perfusion and oxyhemoglobin saturation in skeletal muscle during submaximal isometric contractions.

    Science.gov (United States)

    Elder, Christopher P; Cook, Ryan N; Chance, Marti A; Copenhaver, Elizabeth A; Damon, Bruce M

    2010-09-01

    The relative oxygen saturation of hemoglobin and the rate of perfusion are important physiological quantities, particularly in organs such as skeletal muscle, in which oxygen delivery and use are tightly coupled. The purpose of this study was to demonstrate the image-based calculation of the relative oxygen saturation of hemoglobin and quantification of perfusion in skeletal muscle during isometric contractions. This was accomplished by establishing an empirical relationship between the rate of radiofrequency-reversible dephasing and near-infrared spectroscopy-observed oxyhemoglobin saturation (relative oxygen saturation of hemoglobin) under conditions of arterial occlusion and constant blood volume. A calibration curve was generated and used to calculate the relative oxygen saturation of hemoglobin from radiofrequency-reversible dephasing changes measured during contraction. Twelve young healthy subjects underwent 300 s of arterial occlusion and performed isometric contractions of the dorsiflexors at 30% of maximal contraction for 120 s. Muscle perfusion was quantified during contraction by arterial spin labeling and measures of muscle T(1). Comparisons between the relative oxygen saturation of hemoglobin values predicted from radiofrequency-reversible dephasing and that measured by near-infrared spectroscopy revealed no differences between methods (P = 0.760). Muscle perfusion reached a value of 34.7 mL 100 g(-1) min(-1) during contraction. These measurements hold future promise in measuring muscle oxygen consumption in healthy and diseased skeletal muscle. 2010 Wiley-Liss, Inc.

  14. A model of local distribution of saturation in a fractured layer, and its application

    Energy Technology Data Exchange (ETDEWEB)

    Yuichi Niibori; Tadashi Chida

    1994-01-20

    This paper describes a model of local distribution of liquid water (or steam) saturation in a fractured layer. The model, based on the Bernoulli trials as a probability density function of saturation, gives the following relation between the average value of the relative permeability for the water phase, k{sub rwa}, and the arithmetical mean of saturation, S{sub wa}: k{sub rwa}=S{sub wa}{sup m} where m is an index representing the non-uniformity of saturation (1<=m<=4). When m=4, the saturation is distributed uniformly. The proposed model also gives the average value for the relative permeability of the steam phase, k{sub rga}, as follows: k{sub rga}=1-S{sub wa}{sup m}-2S{sub wa}+2S{sub wa}{sup (2m+1)/3} These relations are applied to analysis of some experimental data already reported by the authors. Also, this presentation shows the validity of the Bernoulli trials as a density probability function of saturation in comparison with other kinds of such functions: the normal distribution, the triangle distribution and the beta distribution.

  15. Effects of water saturation on P-wave propagation in fractured coals: An experimental perspective

    Science.gov (United States)

    Liu, Jie; Liu, Dameng; Cai, Yidong; Gan, Quan; Yao, Yanbin

    2017-09-01

    Internal structure of coalbed methane (CBM) reservoirs can be evaluated through ultrasonic measurements. The compressional wave that propagates in a fractured coal reservoir may indicate the internal coal structure and fluid characteristics. The P-wave propagation was proposed to study the relations between petrophysical parameters (including water saturation, fractures, porosity and permeability) of coals and the P-wave velocity (Vp), using a KON-NM-4A ultrasonic velocity meter. In this study, the relations between Vps and water saturations were established: Type I is mainly controlled by capillary of developed seepage pores. The controlling factors on Type II and Type III are internal homogeneity of pores/fractures and developed micro-fractures, respectively. Micro-fractures density linearly correlates with the Vp due to the fracture volume and dispersion of P-wave; and micro-fractures of types C and D have a priority in Vp. For dry coals, no clear relation exists between porosity, permeability and the Vp. However, as for water-saturated coals, the correlation coefficients of porosity, permeability and Vp are slightly improved. The Vp of saturated coals could be predicted with the equation of Vp-saturated = 1.4952Vp-dry-26.742 m/s. The relation between petrophysical parameters of coals and Vp under various water saturations can be used to evaluate the internal structure in fractured coals. Therefore, these relations have significant implications for coalbed methane (CBM) exploration.

  16. A study on the saturation degree dependency of the seismic behaviour of retaining walls

    Directory of Open Access Journals (Sweden)

    Momeni M.J.

    2016-01-01

    Full Text Available Retaining walls are important geotechnical structures that are often used in soil slopes and trenches to bring ground surface at appropriate level for the construction of roads, highways and buildings. It is common practice to assume that the soil behind a retaining structure is either fully saturated or completely dry. However, for the case the soil is partially saturated, mechanical behaviour of the soil above the water table is different than that of the dry soil. Thus, it is necessary to investigate the effect of the variations of degree of saturation on lateral pressure behind retaining walls. In this research, the seismic behaviour of unsaturated soils behind a retaining structure is analysed. A finite difference code was employed to conduct the necessary analyses and a series of equivalent linear analyses is performed to reveal the effect of the degree of saturation on the general response of the retaining structures. The required functions for unsaturated zone were defined and implemented in the code. For this purpose, a soil water retention function was employed and the soil shear modulus is assumed to vary with the mean effective stress for both saturated and unsaturated zones which naturally introduces the required hydro-mechanical coupling in unsaturated and saturated zone. The results of the analyses compared to the conventional methods which does not include the unsaturated mechanical properties, indicate that in the unsaturated state, the increase in the effective stress, and hence, the shear modulus considerably affects the seismic forces on the retaining wall.

  17. Oxygen Saturation in the Dental Pulp of Maxillary Premolars in Different Age Groups - Part 1.

    Science.gov (United States)

    Estrela, Carlos; Serpa, Giuliano C; Alencar, Ana Helena G; Bruno, Kely F; Barletta, Fernando B; Felippe, Wilson T; Estrela, Cyntia R A; Souza, João B

    2017-01-01

    The aim of this study was to determine oxygen saturation levels in the dental pulp of maxillary premolars in different age groups. A total of 120 human maxillary premolars with normal dental pulps were selected covering the following age groups: 20-24, 25-29, 30-34, 35-39 and 40-44 years (n=24 each group). Oxygen saturation was assessed using pulse oximetry. Analysis of variance was used to assess differences in oxygen saturation levels and Tukey's test was used to identify the age groups that differed from each other. Significance was set at 0.05. Mean oxygen saturation of 120 premolars was 86.20% considering all age groups. Significantly reduced levels were found in the oldest group compared to the other groups: 40 to 44 years - 80.00% vs. 89.71, 87.67, 88.71, and 84.80% for age groups 20-24, 25-29, 30-34, 35-39 years, respectively. The mean oxygen saturation levels were similar between 20 and 39 years of age (86.20%) in the whole sample, but reduced significantly in the 40-44-year age group, suggesting that older patients present lower oxygen saturation results even in the absence of pulp tissue injury.

  18. Impact of Reservoir Fluid Saturation on Seismic Parameters: Endrod Gas Field, Hungary

    Science.gov (United States)

    El Sayed, Abdel Moktader A.; El Sayed, Nahla A.

    2017-12-01

    Outlining the reservoir fluid types and saturation is the main object of the present research work. 37 core samples were collected from three different gas bearing zones in the Endrod gas field in Hungary. These samples are belonging to the Miocene and the Upper - Lower Pliocene. These samples were prepared and laboratory measurements were conducted. Compression and shear wave velocity were measured using the Sonic Viewer-170-OYO. The sonic velocities were measured at the frequencies of 63 and 33 kHz for compressional and shear wave respectively. All samples were subjected to complete petrophysical investigations. Sonic velocities and mechanical parameters such as young’s modulus, rigidity, and bulk modulus were measured when samples were saturated by 100%-75%-0% brine water. Several plots have been performed to show the relationship between seismic parameters and saturation percentages. Robust relationships were obtained, showing the impact of fluid saturation on seismic parameters. Seismic velocity, Poisson’s ratio, bulk modulus and rigidity prove to be applicable during hydrocarbon exploration or production stages. Relationships among the measured seismic parameters in gas/water fully and partially saturated samples are useful to outline the fluid type and saturation percentage especially in gas/water transitional zones.

  19. The influence of saturation on the cracking process in compacted desiccating clays

    Directory of Open Access Journals (Sweden)

    Noack Maria

    2016-01-01

    Full Text Available Tensile failure in unsaturated cohesive soils during desiccation is important for the design of geotechnical applications such as capping systems of landfills and sealing material of dikes. This study presents the results of different initial parameters of compacted clay samples such as gravimetric water content, dry density and degree of saturation. These parameters are varied systematically for each test to find the correlation between those parameters and the tensile failure. The tensile failure for all tests occurred by a comparable constant change of the degree of saturation. The soil specific saturation ratio Sr,s is defined as the quotient of saturation changes ΔSr to initial saturation Sr,0. This parameter related to the total suction shows an equal course for all results. All in all, the course of the soil specific saturation ratio Sr,s is independent of all initial parameters. These results provide a physical and hydraulic-mechanical description for modelling the desiccation process. To demonstrate the initiation and progress of tensile failure, the experimental results are modelled with a Discrete Element Method (DEM approach.

  20. Electrical conductance of a sandstone partially saturated with varying concentrations of NaCl solutions

    Science.gov (United States)

    Umezawa, R.; Nishiyama, N.; Katsura, M.; Nakashima, S.

    2017-05-01

    Electrical conductance G at 100 kHz of Berea sandstone initially saturated with varying NaCl concentrations was measured by an impedance meter at decreasing water saturation. The obtained conductance G values can be well simulated by the model equation composed of conductance of bulk pore water and that of mineral surfaces by introducing both tortuosities of bulk pore water τb and mineral surfaces τs. The surface conductivity Σs = 2.1 × 10- 10 S and the tortuosity of mineral surfaces τs = 2.6 in this equation can be valid for most of the data at varying water saturation except for the lowest water saturation (Sw = 0.05). The tortuosity of pore water τb increased from 1.7 at Sw = 1.0 to 15 at Sw = 0.05 with a power law relationship. The present electrical conduction model with double tortuosities of bulk pore water τb and mineral surfaces τs can be considered as an alternative expression of the combined Archie's first and second laws in terms of tortuosities and would be useful for describing conductance of electrolyte containing partially saturated rocks including very low water saturation.