Science.gov

Sample records for active grain density

  1. Optimization of strength and ductility in nanotwinned ultrafine grained Ag: twin density and grain orientations

    SciTech Connect

    Ott, R. T.; Geng, J.; Besser, M. F.; Kramer, M. J.; Wang, Y. M.; Park, E. S.; LeSar, R.; King, A. H.

    2015-06-27

    Nanotwinned ultrafine grained Ag thick films with different twin densities and orientations have been synthesized by magnetron sputtering with a wide-range of deposition rates. The twin boundary (TB) spacings and orientations as well as the grain size for the different deposition conditions have been characterized by both synchrotron X-ray scattering and transmission electron microscopy (TEM). Structural characterization combined with uniaxial tensile tests of the free-standing films reveals a large increase in the yield strength for films deposited at high deposition rates without any accompanying change in the TB spacing – a behavior that is in contrast with what has been reported in the literature. We find that films deposited at lower deposition rates exhibit more randomly oriented grains with a lower overall twin density (averaged over all the grains) than the more heavily twinned grains with strong <111> fiber texture in the films deposited at higher deposition rates. The TB spacing in the twinned grains, however, does not show any significant dependence on the deposition rate. The dependence of the strength and ductility on the twin density and orientations can be described by two different soft deformation modes: 1) untwinned grains and 2) nanowinned grains that are not oriented with <111> along the growth direction. The untwinned grains provide relatively low resistance to slip, and thus decreased strength, while the nanotwinned grains that are not oriented with <111> along the growth direction are softer than nanotwinned grains that are oriented with <111> along the growth direction. We reveal that an ultrafine-grained (150-200 nm) structure consisting of a mixture of nanotwinned (~ 8-12 nm spacing) and untwined grains yields the best combination of high strength and uniform tensile ductility.

  2. Optimization of strength and ductility in nanotwinned ultrafine grained Ag: twin density and grain orientations

    DOE PAGES

    Ott, R. T.; Geng, J.; Besser, M. F.; Kramer, M. J.; Wang, Y. M.; Park, E. S.; LeSar, R.; King, A. H.

    2015-06-27

    Nanotwinned ultrafine grained Ag thick films with different twin densities and orientations have been synthesized by magnetron sputtering with a wide-range of deposition rates. The twin boundary (TB) spacings and orientations as well as the grain size for the different deposition conditions have been characterized by both synchrotron X-ray scattering and transmission electron microscopy (TEM). Structural characterization combined with uniaxial tensile tests of the free-standing films reveals a large increase in the yield strength for films deposited at high deposition rates without any accompanying change in the TB spacing – a behavior that is in contrast with what has beenmore » reported in the literature. We find that films deposited at lower deposition rates exhibit more randomly oriented grains with a lower overall twin density (averaged over all the grains) than the more heavily twinned grains with strong <111> fiber texture in the films deposited at higher deposition rates. The TB spacing in the twinned grains, however, does not show any significant dependence on the deposition rate. The dependence of the strength and ductility on the twin density and orientations can be described by two different soft deformation modes: 1) untwinned grains and 2) nanowinned grains that are not oriented with <111> along the growth direction. The untwinned grains provide relatively low resistance to slip, and thus decreased strength, while the nanotwinned grains that are not oriented with <111> along the growth direction are softer than nanotwinned grains that are oriented with <111> along the growth direction. We reveal that an ultrafine-grained (150-200 nm) structure consisting of a mixture of nanotwinned (~ 8-12 nm spacing) and untwined grains yields the best combination of high strength and uniform tensile ductility.« less

  3. Plant Density Effect on Grain Number and Weight of Two Winter Wheat Cultivars at Different Spikelet and Grain Positions

    PubMed Central

    Ni, Yingli; Zheng, Mengjing; Yang, Dongqing; Jin, Min; Chen, Jin; Wang, Zhenlin; Yin, Yanping

    2016-01-01

    In winter wheat, grain development is asynchronous. The grain number and grain weight vary significantly at different spikelet and grain positions among wheat cultivars grown at different plant densities. In this study, two winter wheat (Triticum aestivum L.) cultivars, ‘Wennong6’ and ‘Jimai20’, were grown under four different plant densities for two seasons, in order to study the effect of plant density on the grain number and grain weight at different spikelet and grain positions. The results showed that the effects of spikelet and grain positions on grain weight varied with the grain number of spikelets. In both cultivars, the single-grain weight of the basal and middle two-grain spikelets was higher at the 2nd grain position than that at the 1st grain position, while the opposite occurred in the top two-grain spikelets. In the three-grain spikelets, the distribution of the single-grain weight was different between cultivars. In the four-grain spikelets of Wennong6, the single-grain weight was the highest at the 2nd grain position, followed by the 1st, 3rd, and 4th grain positions. Regardless of the spikelet and grain positions, the single-grain weight was the highest at the 1st and 2nd grain positions and the lowest at the 3rd and 4th grain positions. Overall, plant density affected the yield by controlling the seed-setting characteristics of the tiller spike. Therefore, wheat yield can be increased by decreasing the sterile basal and top spikelets and enhancing the grain weight at the 3rd and 4th grain positions, while maintaining it at the 1st and 2nd grain positions on the spikelet. PMID:27171343

  4. Reducing the graphene grain density in three steps

    NASA Astrophysics Data System (ADS)

    Hsieh, Ya-Ping; Chu, Yi-Hung; Tsai, He-Guang; Hofmann, Mario

    2016-03-01

    The production of large-scale, single crystalline graphene is a requirement for enhancing its electronic, mechanical, and chemical properties. Chemical vapor deposition (CVD) has shown the potential to grow high quality graphene but the simultaneous nucleation of many grains limits their achievable domain size. We report here that ultralow nucleation densities can be achieved through multi-step optimization of the catalyst morphology. First, annealing in a hydrogen-free environment is required to retain a surface copper oxide which decreases the nucleation density. Second, CuO was found to be the relevant copper species for this process and air oxidation of the copper foil at 200 °C maximizes its concentration. Both pre-treatment steps were found to affect the morphology of the catalyst and a direct correlation between nucleation density and surface roughness was found which indicates that the primary role of the oxidation step is the decrease in catalyst roughness. To further enhance this determining parameter, confined CVD was carried out after sample oxidation and hydrogen-free annealing. Each of these three steps reduces the grain density by approximately one order of magnitude resulting in ultralow nucleation densities of 1.23 grains/mm2 and high quality, single-crystalline graphene grains of several millimeter sizes were grown using this method.

  5. Estimate of snow density knowing grain and share hardness

    NASA Astrophysics Data System (ADS)

    Valt, Mauro; Cianfarra, Paola; Cagnati, Anselmo; Chiambretti, Igor; Moro, Daniele

    2010-05-01

    Alpine avalanche warning services produces, weekly, snow profiles. Usually such profiles are made in horizontal snow fields, homogenously distributed by altitude and climatic micro-areas. Such profile allows grain shape, dimension and hardness (hand test) identification. Horizontal coring of each layer allows snow density identification. Such data allows the avalanche hazard evaluation and an estimation of the Snow Water Equivalent (SWE). Nevertheless the measurement of snow density, by coring, of very thin layers (less than 5 cm of thickness) is very difficult and are usually not measured by snow technicians. To bypass such problems a statistical analysis was performed to assign density values also to layers which cannot be measured. This system allows, knowing each layer thickness and its density, to correctly estimate SWE. This paper presents typical snow density values for snow hardness values and grain types for the Eastern Italian Alps. The study is based onto 2500 snow profiles with 17000 sampled snow layers from the Dolomites and Venetian Prealps (Eastern Alps). The table of typical snow density values for each grain type is used by YETI Software which elaborate snow profiles and automatically evaluate SWE. This method allows a better use of Avalanche Warning Services datasets for SWE estimation and local evaluation of SWE yearly trends for each snow field.

  6. Grain-based activated carbons for natural gas storage.

    PubMed

    Zhang, Tengyan; Walawender, Walter P; Fan, L T

    2010-03-01

    Natural gas has emerged as a potential alternative to gasoline due to the increase in global energy demand and environmental concerns. An investigation was undertaken to explore the technical feasibility of implementing the adsorbed natural gas (ANG) storage in the fuel tanks of motor vehicles with activated carbons from biomass, e.g., sorghum and wheat. The grain-based activated carbons were prepared by chemical activation; the experimental parameters were varied to identify the optimum conditions. The porosity of the resultant activated carbons was evaluated through nitrogen adsorption; and the storage capacity, through methane adsorption. A comparative study was also carried out with commercial activated carbons from charcoal. The highest storage factor attained was 89 for compacted grain-based activated carbons from grain sorghum with a bulk density of 0.65 g/cm(3), and the highest storage factor attained is 106 for compacted commercial activated carbons (Calgon) with a bulk density of 0.70 g/cm(3). The storage factor was found to increase approximately linearly with increasing bulk density and to be independent of the extent of compaction. This implies that the grain-based activated carbons are the ideal candidates for the ANG storage.

  7. Predicting stored grain insect population densities using an electronic probe trap.

    PubMed

    Flinn, P W; Opit, G P; Throne, J E

    2009-08-01

    Manual sampling of insects in stored grain is a laborious and time-consuming process. Automation of grain sampling should help to increase the adoption of stored grain integrated pest management. A new commercial electronic grain probe trap (OPI Insector) has recently been marketed. We field tested OPI Insector electronic grain probes in two bins, each containing 32.6 tonnes of wheat, Triticum aestivum L., over a 2-yr period. We developed new statistical models to convert Insector catch into insects per kilogram. We compared grain sample estimates of insect density (insects per kilogram of wheat) taken near each Insector to the model-predicted insect density by using Insector counts. An existing expert system, Stored Grain Advisor Pro, was modified to automatically read the Insector database and use the appropriate model to estimate Cryptolestes ferrugineus (Stephens), Rhyzopertha dominica (F.), and Tribolium castaneum (Herbst) density from trap catch counts. Management decisions using Insector trap-catch estimates for insect density were similar to those made using grain sample estimates of insect density for most sampling dates. However, because of the similarity in size of R. dominica and T. castaneum, the software was unable to differentiate counts between these two species. In the central and southern portions of the United States, where both species frequently occur, it may be necessary to determine the proportion of each species present in the grain by manual inspection of trap catch. The combination of SGA Pro with the OPI Insector system should prove to be a useful tool for automatic monitoring of insect pests in stored grain.

  8. Analysis of defect structure in silicon. Effect of grain boundary density on carrier mobility in UCP material

    NASA Technical Reports Server (NTRS)

    Dunn, J.; Stringfellow, G. B.; Natesh, R.

    1982-01-01

    The relationships between hole mobility and grain boundary density were studied. Mobility was measured using the van der Pauw technique, and grain boundary density was measured using a quantitative microscopy technique. Mobility was found to decrease with increasing grain boundary density.

  9. High-Density Amorphous Ice, the Frost on Interstellar Grains

    NASA Technical Reports Server (NTRS)

    Jenniskens, P.; Blake, D. F.; Wilson, M. A.; Pohorille, A.

    1995-01-01

    Most water ice in the universe is in a form which does not occur naturally on Earth and of which only minimal amounts have been made in the laboratory. We have encountered this 'high-density amorphous ice' in electron diffraction experiments of low-temperature (T less than 30 K) vapor-deposited water and have subsequently modeled its structure using molecular dynamics simulations. The characteristic feature of high-density amorphous ice is the presence of 'interstitial' oxygen pair distances between 3 and 4 A. However, we find that the structure is best described as a collapsed lattice of the more familiar low-density amorphous form. These distortions are frozen in at temperatures below 38 K because, we propose, it requires the breaking of one hydrogen bond, on average, per molecule to relieve the strain and to restructure the lattice to that of low-density amorphous ice. Several features of astrophysical ice analogs studied in laboratory experiments are readily explained by the structural transition from high-density amorphous ice into low-density amorphous ice. Changes in the shape of the 3.07 gm water band, trapping efficiency of CO, CO loss, changes in the CO band structure, and the recombination of radicals induced by low-temperature UV photolysis all covary with structural changes that occur in the ice during this amorphous to amorphous transition. While the 3.07 micrometers ice band in various astronomical environments can be modeled with spectra of simple mixtures of amorphous and crystalline forms, the contribution of the high-density amorphous form nearly always dominates.

  10. Murchison presolar carbon grains of different density fractions: A Raman spectroscopic perspective

    NASA Astrophysics Data System (ADS)

    Wopenka, B.; Xu, Y. C.; Zinner, E.; Amari, S.

    2013-04-01

    Raman analyses are reported of μm-sized areas of 103 individual carbonaceous presolar grains ("graphite grains") from three different density fractions of the Murchison meteorite. Few of the grains (2 or 3 of each density fraction) have Raman spectra typical for non-crystalline sp2-bonded carbon (i.e., "organic carbon") with extremely wide 1st-order and no (or very subdued) 2nd-order peaks, similar to the ones found for terrestrial kerogens. Based on depth profiles of isotopic ratios measured with the NanoSIMS, it is unlikely that such kerogen-type Raman signatures are caused by contamination of the presolar grains with insoluble organic material from the Murchison matrix that stuck to the surfaces of the grains. Rather, the kerogen-type grains are considered to be a new type of presolar carbon grains, which are made up of organic (PAH-like) sp2-bonded carbon. However, most of the other studied presolar carbon grains (95 of 103) have spectra with very narrow 1st-order peaks (called D and G peaks) and very strong 2nd-order peaks typical for inorganic sp2-bonded carbon. Based on their D/G intensity ratios, those grains were grouped into the following Raman types: (fairly well ordered) "graphite" (D/G < 0.5), "disordered graphite" (0.5 < D/G < 1.1), "glassy carbon" (D/G > 1.1), and "unusual sp2-bonded graphitic carbon" (with extremely intense 2nd-order peaks relative to the 1st-order peaks). Grains from the low-density fraction KFA1 (2.05-2.10 g/cm3) have predominantly "cauliflower" morphology and Raman spectra characteristic of either very disordered graphite or "glassy carbon" (i.e., the latter is amorphous from the Raman spectroscopic perspective), whereas most grains from the high-density fraction KFC1 (2.15-2.20 g/cm3) have "onion" morphology and Raman spectra characteristic of well-crystalline graphite. The KFB1 grains with intermediate density (2.10-2.15 g/cm3) are mixed, both in terms of their morphology and their Raman spectra but are closer to KFC1 than to

  11. C, N, AND O ISOTOPIC HETEROGENEITIES IN LOW-DENSITY SUPERNOVA GRAPHITE GRAINS FROM ORGUEIL

    SciTech Connect

    Groopman, Evan; Bernatowicz, Thomas; Zinner, Ernst

    2012-07-20

    We report on the results of NanoSIMS isotope imaging of low-density supernova graphite grains from the Orgueil meteorite. 70 nm thick microtomed sections of three supernova graphite grains were deposited on Si wafers and isotopically imaged in the NanoSIMS. These sections contain hotspots of excesses in {sup 18}O and {sup 15}N, which are spatially well correlated, and are likely carried by internal TiC subgrains. These hotspots are considerably more enriched in {sup 18}O and {sup 15}N than the host graphite grain. Correlations between {sup 18}O and {sup 15}N excesses indicate that the grains incorporated material from the He/C supernova zone. Isotope images of the surfaces of some grains show heterogeneities in their N and O isotope compositions, with extreme excesses in {sup 15}N and {sup 18}O. In the microtome sections, we also observe two types of heterogeneities in the grains' C isotopic compositions: smooth, radial gradients in {sup 12}C/{sup 13}C, with this ratio trending toward solar with increasing radius; and highly anomalous pockets up to 2 {mu}m in size with {sup 12}C/{sup 13}C >> solar that are located near the centers of the grain sections. Partial isotopic equilibration does not likely explain the C isotopic heterogeneities. These grains and their constituent parts probably formed in a stellar environment with changing isotopic composition.

  12. Activation Energy for Grain Growth in Aluminum Coatings

    SciTech Connect

    Jankowski, A F; Ferreira, J L; Hayes, J P

    2004-10-14

    To produce a specific grain size in metallic coatings requires precise control of the time at temperature during the deposition process. Aluminum coatings are deposited using electron-beam evaporation onto heated substrate surfaces. The grain size of the coating is determined upon examination of the microstructure in plan view and cross-section. Ideal grain growth is observed over the entire experimental range of temperature examined from 413 to 843 K. A transition in the activation energy for grain growth from 0.7 to 3.8 eV {center_dot} atom{sup -1} is observed as the temperature increases from <526 K to >588 K. The transition is indicative of the dominant mechanism for grain growth shifting with increasing temperature from grain boundary to lattice diffusion.

  13. Sintering Trajectories: Description on How Density, Surface Area, and Grain Size Change

    NASA Astrophysics Data System (ADS)

    German, Randall M.

    2016-03-01

    Sintering is a mainstay production step in forming metal, ceramic, polymer, and composite components from particles. Since the 1940s, the sintering process is treated using a matrix of mathematical relationships that include at least seven atomic transport mechanisms, several options on powder characteristics, and three pore-grain morphology options. The interplay of these relationships is handled by numerical solutions to predict property development. An alternative approach is to track the sintering trajectory using relatively simple relationships based on bulk measures. Energy minimization dictates that initial stage sintering acts to reduce surface area. In late stage sintering, the energy minimization turns to grain boundary area reduction via grain growth. Accordingly, relationships result between density, surface area, and grain size, which largely ignore mechanistic details. These relationships are applicable to a wide variety of materials and consolidation conditions, including hot pressing, and spark sintering.

  14. Mechanical and thermal properties of high density polyethylene – dried distillers grains with solubles composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dried Distillers Grain with Solubles (DDGS) is evaluated as a bio-based fiber reinforcement. Injection molded composites of high density polyethylene (HDPE), 25% by weight of DDGS, and either 5% of 0% by weight of maleated polyethylene (MAPE) were produced by twin screw compounding and injection mo...

  15. Stochastic thermodynamics of fluctuating density fields: Non-equilibrium free energy differences under coarse-graining

    SciTech Connect

    Leonard, T.; Lander, B.; Seifert, U.; Speck, T.

    2013-11-28

    We discuss the stochastic thermodynamics of systems that are described by a time-dependent density field, for example, simple liquids and colloidal suspensions. For a time-dependent change of external parameters, we show that the Jarzynski relation connecting work with the change of free energy holds if the time evolution of the density follows the Kawasaki-Dean equation. Specifically, we study the work distributions for the compression and expansion of a two-dimensional colloidal model suspension implementing a practical coarse-graining scheme of the microscopic particle positions. We demonstrate that even if coarse-grained dynamics and density functional do not match, the fluctuation relations for the work still hold albeit for a different, apparent, change of free energy.

  16. Processing Variables of Alumina Slips and Their Effects on the Density and Grain Size of the Sintered Sample

    SciTech Connect

    Rowley, R.; Chu, H.

    2002-01-01

    High densities and small grain size of alumina ceramic bodies provide high strength and better mechanical properties than lower density and larger grain size bodies. The final sintered density and grain size of slip-cast, alumina samples depends greatly on the processing of the slip and the alumina powder, as well as the sintering schedule. There were many different variables explored that include initial powder particle size, slurry solids percent, amount and type of dispersant used, amount and type of binder used, and sintering schedule. Although the experimentation is not complete, to this point the sample with the highest density and smallest grain size has been a SM8/Nano mixture with Darvan C as the dispersant and Polyvinyl Alcohol (PVA) as the binder, with a solids loading of 70 wt% and a 1500 C for 2 hours sintering schedule. The resultant density was 98.81% of theoretical and the average grain size was approximately 2.5 {micro}m.

  17. Fracture density and grain size controls on the relief structure of threshold landscapes

    NASA Astrophysics Data System (ADS)

    DiBiase, R.; Rossi, M. W.; Neely, A.

    2015-12-01

    A central goal in geomorphology is to untangle the competing controls of climate, tectonics, and rock strength on the topography and relief structure of mountain ranges. This is important for deciphering the history of climate and tectonics encoded in landscapes, predicting natural hazards, and quantifying critical zone processes. Incorporating rock strength into landscape evolution models has been a particularly challenging problem, because the factors that determine rock strength vary in importance depending on process. Here we propose a mechanism of hillslope-channel coupling by which tectonically-induced fracturing influences the relief structure of steep, rocky "threshold" landscapes by leading to A) increased fracture density in exposed bedrock outcrops, thereby limiting hillslope relief, and B) decreased grain size of channel bed material, thereby reducing the magnitude of fluvial incision thresholds and increasing the erosional efficiency of bedrock rivers. To test this hypothesis, we compare two contrasting landscapes in southern California—the eastern San Gabriel Mountains and the northern San Jacinto Mountains. The eastern San Gabriel Mountains rise 2 km in relief and exhibit high uplift and erosion rates due to active faulting along the Cucamonga thrust fault. Although bedrock on hillslopes is common, the exposed granitic and metamorphic basement rock is highly fractured at the decimeter or finer scale, and river channels are mantled with a thin layer of gravel-cobble alluvium. The northern San Jacinto Mountains, 80 km to the southeast, experience similar mean runoff and daily runoff variability, and are underlain by similar bedrock. Yet, despite an absence of active faulting, and erosion rates slower than the eastern San Gabriel Mountains by a factor of 5, the northern San Jacinto Mountains preserve one of the steepest escarpments in the contiguous US (2-3 km high), characterized by massive bedrock outcrops on hillslopes with meter-scale or larger

  18. A coarse-grain force field for RDX: Density dependent and energy conserving

    NASA Astrophysics Data System (ADS)

    Moore, Joshua D.; Barnes, Brian C.; Izvekov, Sergei; Lísal, Martin; Sellers, Michael S.; Taylor, DeCarlos E.; Brennan, John K.

    2016-03-01

    We describe the development of a density-dependent transferable coarse-grain model of crystalline hexahydro-1,3,5-trinitro-s-triazine (RDX) that can be used with the energy conserving dissipative particle dynamics method. The model is an extension of a recently reported one-site model of RDX that was developed by using a force-matching method. The density-dependent forces in that original model are provided through an interpolation scheme that poorly conserves energy. The development of the new model presented in this work first involved a multi-objective procedure to improve the structural and thermodynamic properties of the previous model, followed by the inclusion of the density dependency via a conservative form of the force field that conserves energy. The new model accurately predicts the density, structure, pressure-volume isotherm, bulk modulus, and elastic constants of the RDX crystal at ambient pressure and exhibits transferability to a liquid phase at melt conditions.

  19. Activities of key enzymes in sucrose-to-starch conversion in wheat grains subjected to water deficit during grain filling.

    PubMed

    Yang, Jianchang; Zhang, Jianhua; Wang, Zhiqing; Xu, Guowei; Zhu, Qingsen

    2004-07-01

    This study tested the hypothesis that a controlled water deficit during grain filling of wheat (Triticum aestivum) could accelerate grain-filling rate through regulating the key enzymes involved in Suc-to-starch pathway in the grains. Two high lodging-resistant wheat cultivars were field grown. Well-watered and water-deficit (WD) treatments were imposed from 9 DPA until maturity. The WD promoted the reallocation of prefixed 14C from the stems to grains, shortened the grain-filling period, and increased grain-filling rate or starch accumulation rate (SAR) in the grains. Activities of Suc synthase (SuSase), soluble starch synthase (SSS), and starch branching enzyme (SBE) in the grains were substantially enhanced by WD and positively correlated with the SAR. ADP Glc pyrophosphorylase activity was also enhanced in WD grains initially and correlated with SAR with a smaller coefficient. Activities of granule-bound starch synthase and soluble and insoluble acid invertase in the grains were less affected by WD. Abscisic acid (ABA) content in the grains was remarkably enhanced by WD and very significantly correlated with activities of SuSase, SSS, and SBE. Application of ABA on well-watered plants showed similar results as those by WD. Spraying with fluridone, an ABA synthesis inhibitor, had the opposite effect. The results suggest that increased grain-filling rate is mainly attributed to the enhanced sink activity by regulating key enzymes involved in Suc-to-starch conversion, especially SuSase, SSS, and SBE, in wheat grains when subjected to a mild water deficit during grain filling, and ABA plays a vital role in the regulation of this process.

  20. Refractory Organic Compounds in Enceladus' Ice Grains and Hydrothermal Activity

    NASA Astrophysics Data System (ADS)

    Postberg, F.; Khawaja, N.; Hsu, H. W.; Sekine, Y.; Shibuya, T.

    2015-12-01

    Cassini's Cosmic Dust Analyzer (CDA) generates time-of-flight mass spectra of individual grains impinging on the instruments target-plate. Following the analysis of salt rich ice grains emitted by Enceladus that indicated a salt-water ocean in contact with the moon's rocky core [1,2] a recent CDA analysis of nano-phase silica particles pointed at hydrothermal activity at the moon's rock/water interface [3]. The results imply temperatures above 80 - 90°C and alkaline pH values around 10 reminiscent of alkaline hydrothermal vents on Earth like the Lost City Hydrothermal Field. In this context the compositional analysis of organic components in CDA mass spectra of the ejected ice grains is of particular relevance. A multitude of volatile organic species has already been identified in the gas component of the plume [4]. As expected, we find more complex organic molecules in ice grains than in the gas indicating aromatic species, amines, and carbonyl group species. The composition of organic-bearing ice grains displays a great diversity indicating a variety of different organic species in varying concentrations. Recent spatially resolved CDA in situ measurements inside Enceladus' plume indicate that these organic compounds are especially frequent in 'young' ice grains that have just been ejected by high velocity jets. We investigate the implications of our findings with respect to ice grain formation at the water surface and inside the icy vents. We constrain the generation of organic compounds at the rock/water interface in the light of hydrothermal activity and the potential for the formation of life precursor molecules in Enceladus' ocean. Ref:[1] Postberg et al., Nature 459, 1098-1101 (2009). [2] Postberg et al., Nature 474, 620-622 (2011). [3]. Hsu, Postberg, Sekine et al., Nature, 519, 207-210 (2015). [4] Waite et al., Nature 460, 487-490 (2009).

  1. Toward Quantitative Coarse-Grained Models of Lipids with Fluids Density Functional Theory.

    PubMed

    Frink, Laura J Douglas; Frischknecht, Amalie L; Heroux, Michael A; Parks, Michael L; Salinger, Andrew G

    2012-04-10

    We describe methods to determine optimal coarse-grained models of lipid bilayers for use in fluids density functional theory (fluids-DFT) calculations. Both coarse-grained lipid architecture and optimal parametrizations of the models based on experimental measures are discussed in the context of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers in water. The calculations are based on a combination of the modified-iSAFT theory for bonded systems and an accurate fundamental measures theory (FMT) for hard sphere reference fluids. We furthermore discuss a novel approach for pressure control in the fluids-DFT calculations that facilitates both partitioning studies and zero tension control for the bilayer studies. A detailed discussion of the numerical implementations for both solvers and pressure control capabilities are provided. We show that it is possible to develop a coarse-grained lipid bilayer model that is consistent with experimental properties (thickness and area per lipid) of DPPC provided that the coarse-graining is not too extreme. As a final test of the model, we find that the predicted area compressibility moduli and lateral pressure profiles of the optimized models are in reasonable agreement with prior results.

  2. Low pressure shock initiation of porous HMX for two grain size distributions and two densities

    SciTech Connect

    Gustavsen, R.L.; Sheffield, S.A.; Alcon, R.R.

    1995-09-01

    Shock initiation measurements have been made on granular HMX (octotetramethylene tetranitrainine) for two particle size distributions and two densities. Samples were pressed to either 65% or 73% of crystal density from fine ({approx} 10 {mu}m grain size) and coarse (broad distribution of grain sizes peaking at {approx} 150 {mu}m) powders. Planar shocks of 0.2--1 GPa were generated by impacting gas gun driven projectiles on plastic targets containing the HMX. Wave profiles were measured at the input and output of the {approx} 3.9 mm thick HMX layer using electromagnetic particle velocity gauges. The initiation behavior for the two particle size distributions was very different. The coarse HMX began initiating at input pressures as low as 0.5 GPa. Transmitted wave profiles showed relatively slow reaction with most of the buildup occurring at the shock front. In contrast, the fine particle HMX did not begin to initiate at pressures below 0.9 GPa. When the fine powder did react, however, it did so much faster than the coarse HMX. These observations are consistent with commonly held ideas about bum rates being correlated to surface area, and initiation thresholds being correlated with the size and temperature of the hot spots created by shock passage. For each size, the higher density pressings were less sensitive than the lower density pressings.

  3. Aspects of the density field in an active nematic

    PubMed Central

    Mishra, Shradha; Puri, Sanjay; Ramaswamy, Sriram

    2014-01-01

    Active nematics are conceptually the simplest orientationally ordered phase of self-driven particles, but have proved to be a perennial source of surprises. We show here through numerical solution of coarse-grained equations for the order parameter and density that the growth of the active nematic phase from the isotropic phase is necessarily accompanied by a clumping of the density. The growth kinetics of the density domains is shown to be faster than the law expected for variables governed by a conservation law. Other results presented include the suppression of density fluctuations in the stationary ordered nematic by the imposition of an orienting field. We close by posing some open questions. PMID:25332390

  4. Aspects of the density field in an active nematic.

    PubMed

    Mishra, Shradha; Puri, Sanjay; Ramaswamy, Sriram

    2014-11-28

    Active nematics are conceptually the simplest orientationally ordered phase of self-driven particles, but have proved to be a perennial source of surprises. We show here through numerical solution of coarse-grained equations for the order parameter and density that the growth of the active nematic phase from the isotropic phase is necessarily accompanied by a clumping of the density. The growth kinetics of the density domains is shown to be faster than the [Formula: see text] law expected for variables governed by a conservation law. Other results presented include the suppression of density fluctuations in the stationary ordered nematic by the imposition of an orienting field. We close by posing some open questions.

  5. Antioxidant activities of selective gluten free ancient grains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ancient grains were known for special nutritional values along with gluten free qualities. Amaranth, quinoa, teff, buckwheat flours were evaluated for pasting properties, water holding capacity, phenolic contents, and antioxidant activities (free and bound). They all had higher water holding capacit...

  6. Construction of Coarse-Grained Models by Reproducing Equilibrium Probability Density Function

    NASA Astrophysics Data System (ADS)

    Lu, Shi-Jing; Zhou, Xin

    2015-01-01

    The present work proposes a novel methodology for constructing coarse-grained (CG) models, which aims at minimizing the difference between CG model and the corresponding original system. The difference is defined as a functional of their equilibrium conformational probability densities, then is estimated from equilibrium averages of many independent physical quantities denoted as basis functions. An orthonormalization strategy is adopted to get the independent basis functions from sufficiently preselected interesting physical quantities of the system. Thus the current method is named as probability density matching coarse-graining (PMCG) scheme, which effectively takes into account the overall characteristics of the original systems to construct CG model, and it is a natural improvement of the usual CG scheme wherein some physical quantities are intuitively chosen without considering their correlations. We verify the general PMCG framework in constructing a one-site CG water model from TIP3P model. Both structure of liquids and pressure of the TIP3P water system are found to be well reproduced at the same time in the constructed CG model.

  7. A coarse-grain force field for RDX: Density dependent and energy conserving.

    PubMed

    Moore, Joshua D; Barnes, Brian C; Izvekov, Sergei; Lísal, Martin; Sellers, Michael S; Taylor, DeCarlos E; Brennan, John K

    2016-03-14

    We describe the development of a density-dependent transferable coarse-grain model of crystalline hexahydro-1,3,5-trinitro-s-triazine (RDX) that can be used with the energy conserving dissipative particle dynamics method. The model is an extension of a recently reported one-site model of RDX that was developed by using a force-matching method. The density-dependent forces in that original model are provided through an interpolation scheme that poorly conserves energy. The development of the new model presented in this work first involved a multi-objective procedure to improve the structural and thermodynamic properties of the previous model, followed by the inclusion of the density dependency via a conservative form of the force field that conserves energy. The new model accurately predicts the density, structure, pressure-volume isotherm, bulk modulus, and elastic constants of the RDX crystal at ambient pressure and exhibits transferability to a liquid phase at melt conditions. PMID:26979691

  8. [Effects of tillage and straw returning on microorganism quantity, enzyme activities in soils and grain yield].

    PubMed

    Zhao, Ya-li; Guo, Hai-bin; Xue, Zhi-wei; Mu, Xin-yuan; Li, Chao-hai

    2015-06-01

    A two-year field study with split plot design was conducted to investigate the effects of different soil tillage (conventional tillage, CT; deep tillage, DT; subsoil tillage, ST) and straw returning (all straw retention, AS; no straw returning, NS) on microorganism quantity, enzyme activities in soil and grain yield. The results showed that, deep or subsoil tillage and straw returning not only reduced the soil bulk density and promoted the content of organic carbon in soil, but increased the soil microbial quantity, soil enzyme activities and grain yield. Furthermore, such influences in maize season were greater than that in wheat season. Compared with CT+NS, DT+AS and ST+AS decreased the soil bulk density at 20-30 cm depth by 8.5% and 6.6%, increased the content of soil organic carbon by 14.8% and 12.4%, increased the microorganism quantity by 45.9% and 33.9%, increased the soil enzyme activities by 34.1% and 25.5%, increased the grain yield by 18.0% and 19.3%, respectively. No significant difference was observed between DT+AS and ST+AS. We concluded that retaining crop residue and deep or subsoil tillage improved soil microorganism quantity, enzyme activities and crop yield.

  9. Effect of the fused quartz particle density on nucleation and grain control of high-performance multicrystalline silicon ingots

    NASA Astrophysics Data System (ADS)

    Ding, Junjing; Yu, Yunyang; Chen, Wenliang; Zhou, Xucheng; Wu, Zhiyong; Zhong, Genxiang; Huang, Xinming

    2016-11-01

    The nucleation process of high-performance multicrystalline silicon (HP mc-Si) growth seeded by fused quartz particles (FQP) through directional solidification is crucial for the ingot quality. To determine the optimal density of FQP and obtain a better nucleation process and the grain growth, we cast ingots using four different densities of FQP fixed on the bottom of the four quartz crucibles and covered them with a certain thickness of Si3N4 coating. FQP sizes of 30-50 mesh were used, and the influence of the fused quartz particle density on the nucleation mechanism, initial grain uniformity, grain size, density of dislocation clusters, and cell efficiency were analyzed. Compared with the ingots seeded with other three densities of FQP, the 220 particles/cm2 of FQP seeded ingot showed better uniformity of nucleation and initial grains. A large number of small uniform Si grains with lower density of dislocation clusters in the bottom of the ingot were observed. The average conversion efficiency of p-type solar cells manufactured with the 220 particles/cm2 seeded ingot (18.28%) was 0.19% higher than that manufactured with the 120 particles/cm2 seeded ingot (18.09%).

  10. Increasing density leads to generalization in both coarse-grained habitat selection and fine-grained resource selection in a large mammal.

    PubMed

    van Beest, Floris M; Uzal, Antonio; Vander Wal, Eric; Laforge, Michel P; Contasti, Adrienne L; Colville, David; McLoughlin, Philip D

    2014-01-01

    Density is a fundamental driver of many ecological processes including habitat selection. Theory on density-dependent habitat selection predicts that animals should be distributed relative to profitability of habitat, resulting in reduced specialization in selection (i.e. generalization) as density increases and competition intensifies. Despite mounting empirical support for density-dependent habitat selection using isodars to describe coarse-grained (interhabitat) animal movements, we know little of how density affects fine-grained resource selection of animals within habitats [e.g. using resource selection functions (RSFs)]. Using isodars and RSFs, we tested whether density simultaneously modified habitat selection and within-habitat resource selection in a rapidly growing population of feral horses (Equus ferus caballus Linnaeus; Sable Island, Nova Scotia, Canada; 42% increase in population size from 2008 to 2012). Among three heterogeneous habitat zones on Sable Island describing population clusters distributed along a west-east resource gradient (west-central-east), isodars revealed that horses used available habitat in a density-dependent manner. Intercepts and slopes of isodars demonstrated a pattern of habitat selection that first favoured the west, which generalized to include central and east habitats with increasing population size consistent with our understanding of habitat quality on Sable Island. Resource selection functions revealed that horses selected for vegetation associations similarly at two scales of extent (total island and within-habitat zone). When densities were locally low, horses were able to select for sites of the most productive forage (grasslands) relative to those of poorer quality. However, as local carrying capacity was approached, selection for the best of available forage types weakened while selection for lower-quality vegetation increased (and eventually exceeded that of grasslands). Isodars can effectively describe coarse-grained

  11. SMALL GRAIN 1, which encodes a mitogen-activated protein kinase kinase 4, influences grain size in rice.

    PubMed

    Duan, Penggen; Rao, Yuchun; Zeng, Dali; Yang, Yaolong; Xu, Ran; Zhang, Baolan; Dong, Guojun; Qian, Qian; Li, Yunhai

    2014-02-01

    Although grain size is one of the most important components of grain yield, little information is known about the mechanisms that determine final grain size in crops. Here we characterize rice small grain1 (smg1) mutants, which exhibit small and light grains, dense and erect panicles and comparatively slightly shorter plants. The short grain and panicle phenotypes of smg1 mutants are caused by a defect in cell proliferation. The smg1 mutations were identified, using a map-based cloning approach, in mitogen-activated protein kinase kinase 4 (OsMKK4). Relatively higher expression of OsMKK4/SMG1 was detected in younger organs than in older ones, consistent with its role in cell proliferation. Green fluorescent protein (GFP)-OsMKK4/SMG1 fusion proteins appear to be distributed ubiquitously in plant cells. Further results revealed that OsMKK4 influenced brassinosteroid (BR) responses and the expression of BR-related genes. Thus, our findings have identified OsMKK4 as a factor for grain size, and suggest a possible link between the MAPK pathways and BRs in grain growth.

  12. Radon Emanation from Zircon as a Function of Grain Size, Temperature and Fission Track Density

    NASA Astrophysics Data System (ADS)

    Eakin, M.; Barbero, L.; Brownlee, S. J.; Baskaran, M. M.

    2012-12-01

    Radon emanation from rocks and minerals is ubiquitous. Quantification of radon emanation rates from zircon is critical to assess the reliability of U-Pb ages of zircon bearing rocks. The 238U decay chain includes 222Rn, a noble gas, which can readily escape the crystal structure if sufficient escape pathways in lattice structure exist, ultimately leading to a deficiency of 206Pb in the parent crystal. Few studies have directly investigated the link between track density and 222Rn emanation rates, and none have done this for zircon. In order to evaluate the factors affecting radon emanation from the mineral zircon under different conditions, a series of experiments were performed on a large, crushed Mud Tank zircon crystal. Five different grain sizes (500 μm, 250-500 μm, 125-250 μm, 63 - 125 μm, and < 63 μm) were separated and sealed in closed glass jars and radon emanation rates were measured at 25 C. These aliquots are then subjected to a range of temperatures (100 C, 200 C, 400 C, and 600 C) for six hours and the radon emanation rates are measured after each heating step. Fission track densities are measured after the same annealing temperature steps allowing quantification of 222Rn emanation rate as a function of fission track density. The concentration of 210Pb, 234Th, 212Pb, 226Ra and 228Ra in these fractions are also measured using gamma spectroscopy. The results of these experiments will have implications for U-Pb dating (i.e., explanation of discordant ages), and noble gas escape systematics in zircon (i.e., volume diffusion or fast pathway escape). The possibility also exists for using 222Rn, or other noble gasses, as a measure of defect density within crystals.

  13. Activation of Big Grain1 significantly improves grain size by regulating auxin transport in rice.

    PubMed

    Liu, Linchuan; Tong, Hongning; Xiao, Yunhua; Che, Ronghui; Xu, Fan; Hu, Bin; Liang, Chengzhen; Chu, Jinfang; Li, Jiayang; Chu, Chengcai

    2015-09-01

    Grain size is one of the key factors determining grain yield. However, it remains largely unknown how grain size is regulated by developmental signals. Here, we report the identification and characterization of a dominant mutant big grain1 (Bg1-D) that shows an extra-large grain phenotype from our rice T-DNA insertion population. Overexpression of BG1 leads to significantly increased grain size, and the severe lines exhibit obviously perturbed gravitropism. In addition, the mutant has increased sensitivities to both auxin and N-1-naphthylphthalamic acid, an auxin transport inhibitor, whereas knockdown of BG1 results in decreased sensitivities and smaller grains. Moreover, BG1 is specifically induced by auxin treatment, preferentially expresses in the vascular tissue of culms and young panicles, and encodes a novel membrane-localized protein, strongly suggesting its role in regulating auxin transport. Consistent with this finding, the mutant has increased auxin basipetal transport and altered auxin distribution, whereas the knockdown plants have decreased auxin transport. Manipulation of BG1 in both rice and Arabidopsis can enhance plant biomass, seed weight, and yield. Taking these data together, we identify a novel positive regulator of auxin response and transport in a crop plant and demonstrate its role in regulating grain size, thus illuminating a new strategy to improve plant productivity. PMID:26283354

  14. Activation of Big Grain1 significantly improves grain size by regulating auxin transport in rice.

    PubMed

    Liu, Linchuan; Tong, Hongning; Xiao, Yunhua; Che, Ronghui; Xu, Fan; Hu, Bin; Liang, Chengzhen; Chu, Jinfang; Li, Jiayang; Chu, Chengcai

    2015-09-01

    Grain size is one of the key factors determining grain yield. However, it remains largely unknown how grain size is regulated by developmental signals. Here, we report the identification and characterization of a dominant mutant big grain1 (Bg1-D) that shows an extra-large grain phenotype from our rice T-DNA insertion population. Overexpression of BG1 leads to significantly increased grain size, and the severe lines exhibit obviously perturbed gravitropism. In addition, the mutant has increased sensitivities to both auxin and N-1-naphthylphthalamic acid, an auxin transport inhibitor, whereas knockdown of BG1 results in decreased sensitivities and smaller grains. Moreover, BG1 is specifically induced by auxin treatment, preferentially expresses in the vascular tissue of culms and young panicles, and encodes a novel membrane-localized protein, strongly suggesting its role in regulating auxin transport. Consistent with this finding, the mutant has increased auxin basipetal transport and altered auxin distribution, whereas the knockdown plants have decreased auxin transport. Manipulation of BG1 in both rice and Arabidopsis can enhance plant biomass, seed weight, and yield. Taking these data together, we identify a novel positive regulator of auxin response and transport in a crop plant and demonstrate its role in regulating grain size, thus illuminating a new strategy to improve plant productivity.

  15. Activation of Big Grain1 significantly improves grain size by regulating auxin transport in rice

    PubMed Central

    Liu, Linchuan; Tong, Hongning; Xiao, Yunhua; Che, Ronghui; Xu, Fan; Hu, Bin; Liang, Chengzhen; Chu, Jinfang; Li, Jiayang; Chu, Chengcai

    2015-01-01

    Grain size is one of the key factors determining grain yield. However, it remains largely unknown how grain size is regulated by developmental signals. Here, we report the identification and characterization of a dominant mutant big grain1 (Bg1-D) that shows an extra-large grain phenotype from our rice T-DNA insertion population. Overexpression of BG1 leads to significantly increased grain size, and the severe lines exhibit obviously perturbed gravitropism. In addition, the mutant has increased sensitivities to both auxin and N-1-naphthylphthalamic acid, an auxin transport inhibitor, whereas knockdown of BG1 results in decreased sensitivities and smaller grains. Moreover, BG1 is specifically induced by auxin treatment, preferentially expresses in the vascular tissue of culms and young panicles, and encodes a novel membrane-localized protein, strongly suggesting its role in regulating auxin transport. Consistent with this finding, the mutant has increased auxin basipetal transport and altered auxin distribution, whereas the knockdown plants have decreased auxin transport. Manipulation of BG1 in both rice and Arabidopsis can enhance plant biomass, seed weight, and yield. Taking these data together, we identify a novel positive regulator of auxin response and transport in a crop plant and demonstrate its role in regulating grain size, thus illuminating a new strategy to improve plant productivity. PMID:26283354

  16. Allele-dependent barley grain beta-amylase activity.

    PubMed

    Erkkilä, M J; Leah, R; Ahokas, H; Cameron-Mills, V

    1998-06-01

    The wild ancestor of cultivated barley, Hordeum vulgare subsp. spontaneum (K. Koch) A. & Gr. (H. spontaneum), is a source of wide genetic diversity, including traits that are important for malting quality. A high beta-amylase trait was previously identified in H. spontaneum strains from Israel, and transferred into the backcross progeny of a cross with the domesticated barley cv Adorra. We have used Southern-blot analysis and beta-amy1 gene characterization to demonstrate that the high beta-amylase trait in the backcross line is co-inherited with the beta-amy1 gene from the H. spontaneum parent. We have analyzed the beta-amy1 gene organization in various domesticated and wild-type barley strains and identified three distinct beta-amy1 alleles. Two of these beta-amy1 alleles were present in modern barley, one of which was specifically found in good malting barley cultivars. The third allele, linked with high grain beta-amylase activity, was found only in a H. spontaneum strain from the Judean foothills in Israel. The sequences of three isolated beta-amy1 alleles are compared. The involvement of specific intron III sequences, in particular a 126-bp palindromic insertion, in the allele-dependent expression of beta-amylase activity in barley grain is proposed.

  17. Allele-Dependent Barley Grain β-Amylase Activity1

    PubMed Central

    Erkkilä, Maria J.; Leah, Robert; Ahokas, Hannu; Cameron-Mills, Verena

    1998-01-01

    The wild ancestor of cultivated barley, Hordeum vulgare subsp. spontaneum (K. Koch) A. & Gr. (H. spontaneum), is a source of wide genetic diversity, including traits that are important for malting quality. A high β-amylase trait was previously identified in H. spontaneum strains from Israel, and transferred into the backcross progeny of a cross with the domesticated barley cv Adorra. We have used Southern-blot analysis and β-amy1 gene characterization to demonstrate that the high β-amylase trait in the backcross line is co-inherited with the β-amy1 gene from the H. spontaneum parent. We have analyzed the β-amy1 gene organization in various domesticated and wild-type barley strains and identified three distinct β-amy1 alleles. Two of these β-amy1 alleles were present in modern barley, one of which was specifically found in good malting barley cultivars. The third allele, linked with high grain β-amylase activity, was found only in a H. spontaneum strain from the Judean foothills in Israel. The sequences of three isolated β-amy1 alleles are compared. The involvement of specific intron III sequences, in particular a 126-bp palindromic insertion, in the allele-dependent expression of β-amylase activity in barley grain is proposed. PMID:9625721

  18. Physical Activity and Bone Density in Women

    NASA Technical Reports Server (NTRS)

    Bowley, Susan M.; Whalen, R. T.

    2000-01-01

    A mathematical model of bone density regulation as a function of the daily tissue "effective" stress has been derived. Using the model, the influence of daily activity in the form of a daily loading history has been related to bone density of the calcaneus. The theory incorporates a stress exponent m to account for differences in the importance of magnitude and number of load cycles experienced during daily activity. We have derived a parameter from the model, the "Bone Density Index" (BDI). We have developed a method of collecting daily habitual loading histories using an insole force sensor interfaced to a portable digital data logger carried in a fanny pack. Our goal for this study was to determine a stress exponent, m, relating GRFz history to Calcaneal Bone Mineral Density (CBMD).

  19. Strain localization in ultramylonitic marbles by simultaneous activation of dislocation motion and grain boundary sliding (Syros, Greece)

    NASA Astrophysics Data System (ADS)

    Rogowitz, A.; White, J. C.; Grasemann, B.

    2016-03-01

    Extreme strain localization occurred in the centre of the cross-cutting element of a flanking structure in almost pure calcite marbles from Syros, Greece. At the maximum displacement of 120 cm along the cross-cutting element, evidence of grain size sensitive deformation mechanisms can be found in the ultramylonitic marbles, which are characterized by (1) an extremely small grain size ( ˜ 3 µm), (2) grain boundary triple junctions with nearly 120° angles, (3) a weak crystallographic preferred orientation with very low texture index (J = 1.4), (4) a random misorientation angle distribution curve and (5) the presence of small cavities. Using transmission electron microscopy, a deformation sequence is observed comprising recrystallization dominantly by bulging, resulting in the development of the fine-grained ultramylonite followed by the development of a high dislocation density ( ˜ 1013 m-2) with ongoing deformation of the fine-grained ultramylonite. The arrangement of dislocations in the extremely fine-grain-sized calcite differs from microstructures created by classical dislocation creep mediated by combined glide and thermally activated climb. Instead, it exhibits extensive glide and dislocation networks characteristic of recovery accommodated by cross-slip and network-assisted dislocation movement without formation of idealized subgrain walls. The enabling of grain boundary sliding to dislocation activity is deemed central to initiating and sustaining strain softening and is argued to be an important strain localization process in calcite rocks, even at a high strain rate ( ˜ 10-9 s-1) and low temperature (300 °C).

  20. Strain localization in ultramylonitic marbles by simultaneous activation of dislocation motion and grain boundary sliding (Syros, Greece)

    NASA Astrophysics Data System (ADS)

    Rogowitz, A.; White, J. C.; Grasemann, B.

    2015-09-01

    Extreme strain localization occurred in the center of the cross-cutting element of a flanking structure in almost pure calcite marbles from Syros, Greece. At the maximum displacement of 120 cm along the cross-cutting element evidence of grain size sensitive deformation mechanisms can be found in the ultramylonitic marbles, which are characterized by (1) an extremely small grain size (∼3 μm), (2) grain boundary triple junctions with nearly 120° angles, (3) a weak crystallographic preferred orientation with very low texture index (J=1.4), (4) a random misorientation angle distribution curve and (5) the presence of small cavities. Using transmission electron microscopy a deformation sequence is observed comprising, first recrystallization by bulging resulting in the development of the fine-grained ultramylonite followed by the evolution of a high dislocation density (∼1013 m-2) with ongoing deformation of the fine-grained ultramylonite. The arrangement of dislocations in the extremely fine grain sized calcite differs from microstructures created by classical dislocation creep mediated by combined glide and thermally activated climb. Instead, it exhibits extensive glide and dislocation networks characteristic of recovery accommodated by cross-slip and network-assisted dislocation movement without formation of idealized subgrain walls. The enabling of grain boundary sliding to dislocation activity is deemed central to initiating and sustaining strain softening and is argued to be an important strain localization process in calcite rocks, even at high strain rate (10-9 s-1) and low temperature (300 °C).

  1. Radon loss from zircon: emanation and diffusion as a function of grain size, temperature and fission track density

    NASA Astrophysics Data System (ADS)

    Eakin, M.; Brownlee, S. J.; Baskaran, M. M.; Barbero, L.; Walsh, C. N.

    2013-12-01

    Radon emanation from rocks and minerals is ubiquitous, but the mechanisms of radon loss are not well understood. Quantification of radon emanation rates from zircon has potential bearing on the reliability of U-Pb ages of zircon bearing rocks. The 238U decay chain includes 222Rn, a noble gas, which has a half-life of 3.82 days and can escape from the crystal structure of zircon if sufficient pathways exist, or by recoil if the parent 238U was very near the outer edge of the crystal. Loss of 222Rn ultimately leads to a deficiency of 206Pb, resulting in discordance between 238U-206Pb, 235U-207Pb, and 232Th-208Pb ages. In order to evaluate the factors affecting radon loss from zircon, we performed two experiments: one focused on the effect of microstructure on room temperature 222Rn emanation, and the other to investigate 222Rn loss by high temperature diffusion. Large (~100 g) single crystal zircon samples from each of three localities were selected for this study: Mud Tank, Malawi, and Bancroft. The zircons were pulverized and five grain sizes (500 μm, 250-500 μm, 125-250 μm, 63 - 125 μm, and < 63 μm) were separated from each. Room temperature radon emanation rates were measured for an aliquot of each grain size. To investigate the effects of microstructure, in particular fission track density, separate aliquots were heated to temperatures of 200C, 300C, 400C, 600C, and 800C for six hours after which they were cooled to room temperature and radon emanation rates were measured. Fission track densities were measured after the same annealing steps in the Mud Tank zircon, allowing quantification of 222Rn emanation rate as a function of fission track density. In general, radon emanation rates decrease with decreasing fission track density, but increase when all fission tracks are annealed, suggesting the possibility of using 222Rn to assess defect density within crystals. To investigate diffusive loss of 222Rn, we heated separate aliquots of each grain size of the

  2. Detection of powdery mildew in two winter wheat plant densities and prediction of grain yield using canopy hyperspectral reflectance.

    PubMed

    Cao, Xueren; Luo, Yong; Zhou, Yilin; Fan, Jieru; Xu, Xiangming; West, Jonathan S; Duan, Xiayu; Cheng, Dengfa

    2015-01-01

    To determine the influence of plant density and powdery mildew infection of winter wheat and to predict grain yield, hyperspectral canopy reflectance of winter wheat was measured for two plant densities at Feekes growth stage (GS) 10.5.3, 10.5.4, and 11.1 in the 2009-2010 and 2010-2011 seasons. Reflectance in near infrared (NIR) regions was significantly correlated with disease index at GS 10.5.3, 10.5.4, and 11.1 at two plant densities in both seasons. For the two plant densities, the area of the red edge peak (Σdr680-760 nm), difference vegetation index (DVI), and triangular vegetation index (TVI) were significantly correlated negatively with disease index at three GSs in two seasons. Compared with other parameters Σdr680-760 nm was the most sensitive parameter for detecting powdery mildew. Linear regression models relating mildew severity to Σdr680-760 nm were constructed at three GSs in two seasons for the two plant densities, demonstrating no significant difference in the slope estimates between the two plant densities at three GSs. Σdr680-760 nm was correlated with grain yield at three GSs in two seasons. The accuracies of partial least square regression (PLSR) models were consistently higher than those of models based on Σdr680760 nm for disease index and grain yield. PLSR can, therefore, provide more accurate estimation of disease index of wheat powdery mildew and grain yield using canopy reflectance. PMID:25815468

  3. Detection of Powdery Mildew in Two Winter Wheat Plant Densities and Prediction of Grain Yield Using Canopy Hyperspectral Reflectance

    PubMed Central

    Cao, Xueren; Luo, Yong; Zhou, Yilin; Fan, Jieru; Xu, Xiangming; West, Jonathan S.; Duan, Xiayu; Cheng, Dengfa

    2015-01-01

    To determine the influence of plant density and powdery mildew infection of winter wheat and to predict grain yield, hyperspectral canopy reflectance of winter wheat was measured for two plant densities at Feekes growth stage (GS) 10.5.3, 10.5.4, and 11.1 in the 2009–2010 and 2010–2011 seasons. Reflectance in near infrared (NIR) regions was significantly correlated with disease index at GS 10.5.3, 10.5.4, and 11.1 at two plant densities in both seasons. For the two plant densities, the area of the red edge peak (Σdr680–760 nm), difference vegetation index (DVI), and triangular vegetation index (TVI) were significantly correlated negatively with disease index at three GSs in two seasons. Compared with other parameters Σdr680–760 nm was the most sensitive parameter for detecting powdery mildew. Linear regression models relating mildew severity to Σdr680–760 nm were constructed at three GSs in two seasons for the two plant densities, demonstrating no significant difference in the slope estimates between the two plant densities at three GSs. Σdr680–760 nm was correlated with grain yield at three GSs in two seasons. The accuracies of partial least square regression (PLSR) models were consistently higher than those of models based on Σdr680760 nm for disease index and grain yield. PLSR can, therefore, provide more accurate estimation of disease index of wheat powdery mildew and grain yield using canopy reflectance. PMID:25815468

  4. Hemagglutinating activity of polyphenols extracts from six grain legumes.

    PubMed

    Cortés-Giraldo, Isabel; Girón-Calle, Julio; Alaiz, Manuel; Vioque, Javier; Megías, Cristina

    2012-06-01

    The erythrocyte agglutinating activity of polyphenol extracts from six grain legumes was investigated. Polyphenols are amphipathic molecules that can bind to proteins and lipids through hydrophobic and polar interactions, leading to agglutination of liposomes and bacteria. The extracts from four of the six legumes that were studied caused erythrocyte agglutination at concentrations in the μM range. Soybean extracts had the highest activity, followed by the extracts from lentils, broad bean, and chickpea. As a good representative of these legumes, binding of the polyphenols extracted from lentils to erythrocytes was investigated in more detail, showing that agglutination was mediated by binding of 84% of the polyphenols present in the incubation, which corresponds to 2.42 μg bound polyphenols/mg erythrocytes, and a maximum polyphenol binding of 96% according to Lineweaver-Burk plots. The relatively high concentrations that are required for agglutination justify that polyphenols more probably do not agglutinate erythrocytes in vivo, but the possibility still exists that in vivo binding without agglutination could occur, which could have some effects on the metabolism and health-promoting properties of polyphenols. PMID:22497898

  5. Antioxidant Activity of Phytochemicals from Dried Distillers Grain Oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A distillate was obtained by molecular distillation of oil extracted from distiller’s dried grains (DDG). The dried distiller’s grains distillate (DDGD) contained phytosterols, steryl ferulates, tocopherols, tocotrienols, and carotenoids. DDGD was tested for its impact on the oxidative stability i...

  6. Antioxidant activity of phytochemicals from dried distillers grain oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A distillate was obtained by molecular distillation of oil extracted from distiller’s dried grains (DDG). The dried distiller’s grains distillate (DDGD) contained phytosterols, steryl ferulates, tocopherols, tocotrienols, and carotenoids. DDGD was tested for its impact on the oxidative stability in...

  7. Study of the interaction of solutes with Σ5 (013) tilt grain boundaries in iron using density-functional theory

    SciTech Connect

    Jin, Hao; Militzer, Matthias; Elfimov, Ilya

    2014-03-07

    Substitutional alloying elements significantly affect the recrystallization and austenite-ferrite phase transformation rates in steels. The atomistic mechanisms of their interaction with the interfaces are still largely unexplored. Using density functional theory, we determine the segregation energies between commonly used alloying elements and the Σ5 (013) tilt grain boundary in bcc iron. We find a strong solute-grain boundary interaction for Nb, Mo, and Ti that is consistent with experimental observations of the effects of these alloying elements on delaying recrystallization and the austenite-to-ferrite transformation in low-carbon steels. In addition, we compute the solute-solute interactions as a function of solute pair distance in the grain boundary, which suggest co-segregation for these large solutes at intermediate distances in striking contrast to the bulk.

  8. The Effect of Grain Size and Dislocation Density on the Tensile Properties of Ni-SiCNP Composites During Annealing

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Huang, Hefei; Thorogood, Gordon James; Jiang, Li; Ye, Xiangxi; Li, Zhijun; Zhou, Xingtai

    2016-03-01

    The grain size refinement, enhancement of mechanical properties, and static recrystallization behavior of metallic nickel-silicon carbide nano-particle (Ni-3wt.%SiCNP) composites, milled for times ranging from 8 to 48 h have been examined. One set of Ni-SiCNP composite samples were annealed at 300 °C for 250 h, while the other set of samples were maintained at room temperature for control purposes (reference). The electron backscatter diffraction results indicate that the grain size of the annealed Ni-SiCNP composite was refined due to grain restructuring during static recrystallization. The x-ray diffraction results indicate that low-temperature annealing effectively reduced the density of dislocations; this can be explained by the dislocation pile-up model. Additionally, the tensile tests indicated that the annealed Ni-SiCNP composite had a significant increase in strength due to an increase of the Hall-Petch strengthening effect with a slight increase in the total elongation. The decrease of dislocation pile-up in the grain interiors and the increase in grain boundary sliding are assumed to be the main mechanisms at play. The relationship between the microstructural evolution and the variation of tensile properties is examined in this study.

  9. Coarse-grained models using local-density potentials optimized with the relative entropy: Application to implicit solvation

    NASA Astrophysics Data System (ADS)

    Sanyal, Tanmoy; Shell, M. Scott

    2016-07-01

    Bottom-up multiscale techniques are frequently used to develop coarse-grained (CG) models for simulations at extended length and time scales but are often limited by a compromise between computational efficiency and accuracy. The conventional approach to CG nonbonded interactions uses pair potentials which, while computationally efficient, can neglect the inherently multibody contributions of the local environment of a site to its energy, due to degrees of freedom that were coarse-grained out. This effect often causes the CG potential to depend strongly on the overall system density, composition, or other properties, which limits its transferability to states other than the one at which it was parameterized. Here, we propose to incorporate multibody effects into CG potentials through additional nonbonded terms, beyond pair interactions, that depend in a mean-field manner on local densities of different atomic species. This approach is analogous to embedded atom and bond-order models that seek to capture multibody electronic effects in metallic systems. We show that the relative entropy coarse-graining framework offers a systematic route to parameterizing such local density potentials. We then characterize this approach in the development of implicit solvation strategies for interactions between model hydrophobes in an aqueous environment.

  10. A Direct Grain-Boundary-Activity Correlation for CO Electroreduction on Cu Nanoparticles

    PubMed Central

    2016-01-01

    Copper catalyzes the electrochemical reduction of CO to valuable C2+ products including ethanol, acetate, propanol, and ethylene. These reactions could be very useful for converting renewable energy into fuels and chemicals, but conventional Cu electrodes are energetically inefficient and have poor selectivity for CO vs H2O reduction. Efforts to design improved catalysts have been impeded by the lack of experimentally validated, quantitative structure–activity relationships. Here we show that CO reduction activity is directly correlated to the density of grain boundaries (GBs) in Cu nanoparticles (NPs). We prepared electrodes of Cu NPs on carbon nanotubes (Cu/CNT) with different average GB densities quantified by transmission electron microscopy. At potentials ranging from −0.3 V to −0.5 V vs the reversible hydrogen electrode, the specific activity for CO reduction to ethanol and acetate was linearly proportional to the fraction of NP surfaces comprised of GB surface terminations. Our results provide a design principle for CO reduction to ethanol and acetate on Cu. GB-rich Cu/CNT electrodes are the first NP catalysts with significant CO reduction activity at moderate overpotential, reaching a mass activity of up to ∼1.5 A per gram of Cu and a Faradaic efficiency >70% at −0.3 V. PMID:27163043

  11. Coarse-grained density and compressibility of nonideal crystals: General theory and an application to cluster crystals

    NASA Astrophysics Data System (ADS)

    Häring, J. M.; Walz, C.; Szamel, G.; Fuchs, M.

    2015-11-01

    The isothermal compressibility of a general crystal is analyzed within classical density functional theory. Our approach can be used for homogeneous and unstrained crystals containing an arbitrarily high density of local defects. We start by coarse-graining the microscopic particle density and then obtain the long-wavelength limits of the correlation functions of elasticity theory and the thermodynamic derivatives. We explicitly show that the long-wavelength limit of the microscopic density correlation function differs from the isothermal compressibility. We apply our theory to crystals consisting of soft particles which can multiply occupy lattice sites ("cluster crystals"). The multiple occupancy results in a strong local disorder over an extended range of temperatures. We determine the cluster crystals' isothermal compressibility, the fluctuations of the lattice occupation numbers and their correlation functions, and the dispersion relations. We also discuss their low-temperature phase diagram.

  12. Evaluation of a microwave resonator for predicting grain moisture independent of bulk density

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This work evaluated the ability of a planar whispering mode resonator to predict moisture considering moisture and densities expected in an on-harvester application. A calibration model was developed to accurately predict moisture over the moisture, density and temperature ranges evaluated. This mod...

  13. Atomic density effects on temperature characteristics and thermal transport at grain boundaries through a proper bin size selection

    NASA Astrophysics Data System (ADS)

    Vo, Truong Quoc; Barisik, Murat; Kim, BoHung

    2016-05-01

    This study focuses on the proper characterization of temperature profiles across grain boundaries (GBs) in order to calculate the correct interfacial thermal resistance (ITR) and reveal the influence of GB geometries onto thermal transport. The solid-solid interfaces resulting from the orientation difference between the (001), (011), and (111) copper surfaces were investigated. Temperature discontinuities were observed at the boundary of grains due to the phonon mismatch, phonon backscattering, and atomic forces between dissimilar structures at the GBs. We observed that the temperature decreases gradually in the GB area rather than a sharp drop at the interface. As a result, three distinct temperature gradients developed at the GB which were different than the one observed in the bulk solid. This behavior extends a couple molecular diameters into both sides of the interface where we defined a thickness at GB based on the measured temperature profiles for characterization. Results showed dependence on the selection of the bin size used to average the temperature data from the molecular dynamics system. The bin size on the order of the crystal layer spacing was found to present an accurate temperature profile through the GB. We further calculated the GB thickness of various cases by using potential energy (PE) distributions which showed agreement with direct measurements from the temperature profile and validated the proper binning. The variation of grain crystal orientation developed different molecular densities which were characterized by the average atomic surface density (ASD) definition. Our results revealed that the ASD is the primary factor affecting the structural disorders and heat transfer at the solid-solid interfaces. Using a system in which the planes are highly close-packed can enhance the probability of interactions and the degree of overlap between vibrational density of states (VDOS) of atoms forming at interfaces, leading to a reduced ITR. Thus, an

  14. Maternal antibody transfer to broiler progeny varies among strains and is affected by grain source and cage density.

    PubMed

    Leandro, N M; Ali, R; Koci, M; Moraes, V; Eusebio-Balcazar, P E; Jornigan, J; Malheiros, R D; Wineland, M J; Brake, J; Oviedo-Rondón, E O

    2011-12-01

    Two experiments were conducted to examine the effects of broiler breeder dietary grain source and cage density on maternal antibody (MatAb) transfer to progeny in 2 genetic strains (A and B). Broiler breeders were assigned to 16 litter floor pens and fed either corn- or wheat-based diets. Breeders were administered 4 live vaccines against Newcastle disease virus (NDV). At 23 wk of age, pullets and cocks, which reflected the full BW distribution from each treatment, were moved to a cage breeder house and placed at 1 or 2 hens/cage. Breeders were artificially inseminated at 44 wk (experiment 1) and 52 wk of age (experiment 2). Eggs were collected for 8 d, incubated, and placed in individual pedigree bags at d 19 of incubation. Blood samples from 5 chicks per treatment combination were collected at hatch in both experiments. Spleen and bursa were collected from the same chicks for histomorphometry analyses in experiment 2. In the second experiment, 12 chicks per treatment were placed in cages. Progeny were provided diets based on the same grain (corn or wheat) as their parents. Serum samples were collected at 5, 9, and 13 d of age and analyzed for anti-NDV MatAb. Data were analyzed as a 2 × 2 × 2 factorial design considering strain, dietary grain source, and cage density as main factors. Interaction effects were observed in breeders and progeny. Experiment 1 showed that strain A chicks had lower levels of MatAb when hens were housed at 2 hens/cage rather than 1 hen/cage. The MatAb levels of strain B chickens were not affected by cage density in either experiment. Experiment 2 demonstrated similar effects of cage density on MatAb levels and the area of bursa follicles for both strains. Progeny of breeders fed corn-based diets had smaller spleen white pulp only when hens were housed at 2 hens/cage compared with 1 hen/cage. The results of these experiments suggest that breeder strain and cage-density conditions affected MatAb transfer to progeny and embryo development

  15. Microwave sensing of moisture content and bulk density in flowing grain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moisture content and bulk density were determined from measurement of the dielectric properties of flowing wheat kernels at a single microwave frequency (5.8 GHz). The measuring system consisted of two high-gain microwave patch antennas mounted on opposite sides of rectangular chute and connected to...

  16. Grain sorting in the morphological active layer of a braided river physical model

    NASA Astrophysics Data System (ADS)

    Leduc, P.; Ashmore, P.; Gardner, J. T.

    2015-12-01

    A physical scale model of a gravel-bed braided river was used to measure vertical grain size sorting in the morphological active layer aggregated over the width of the river. This vertical sorting is important for analyzing braided river sedimentology, for numerical modeling of braided river morphodynamics, and for measuring and predicting bedload transport rate. We define the morphological active layer as the bed material between the maximum and minimum bed elevations at a point over extended time periods sufficient for braiding processes to rework the river bed. The vertical extent of the active layer was measured using 40 hourly high-resolution DEMs (digital elevation models) of the model river bed. An image texture algorithm was used to map bed material grain size of each DEM. Analysis of the 40 DEMs and texture maps provides data on the geometry of the morphological active layer and variation in grain size in three dimensions. By normalizing active layer thickness and dividing into 10 sublayers, we show that all grain sizes occur with almost equal frequency in all sublayers. Occurrence of patches and strings of coarser (or finer) material relates to preservation of particular morpho-textural features within the active layer. For numerical modeling and bedload prediction, a morphological active layer that is fully mixed with respect to grain size is a reliable approximation.

  17. Grain sorting in the morphological active layer of a braided river physical model

    NASA Astrophysics Data System (ADS)

    Leduc, P.; Ashmore, P.; Gardner, J. T.

    2015-07-01

    A physical scale model of a gravel-bed braided river was used to measure vertical grain size sorting in the morphological active layer aggregated over the width of the river. This vertical sorting is important for analyzing braided river sedimentology, for numerical modeling of braided river morpho-dynamics and for measuring and predicting bed load transport rate. We define the morphological active layer as the bed material between the maximum and minimum bed elevations at a point over extended time periods sufficient for braiding processes to re-work the river bed. The vertical extent of the active layer was measured using 40 hourly high-resolution DEMs of the model river bed. An image texture algorithm was used to map bed material grain size of each DEM. Analysis of the 40 DEMs and texture maps provides data on the geometry of the morphological active layer and variation in grain size in three-dimensions. Normalizing active layer thickness and dividing into 10 sub-layers we show that all grain sizes occur with almost equal frequency in all sub-layers. Occurrence of patches and strings of coarser (or finer) material relates to preservation of particular morpho-textural features within the active layer. For numerical modeling and bed load prediction a morphological active layer that is fully mixed with respect to grain size is a reliable approximation.

  18. Effects of Reduced Terrestrial LiDAR Point Density on High-Resolution Grain Crop Surface Models in Precision Agriculture

    PubMed Central

    Hämmerle, Martin; Höfle, Bernhard

    2014-01-01

    3D geodata play an increasingly important role in precision agriculture, e.g., for modeling in-field variations of grain crop features such as height or biomass. A common data capturing method is LiDAR, which often requires expensive equipment and produces large datasets. This study contributes to the improvement of 3D geodata capturing efficiency by assessing the effect of reduced scanning resolution on crop surface models (CSMs). The analysis is based on high-end LiDAR point clouds of grain crop fields of different varieties (rye and wheat) and nitrogen fertilization stages (100%, 50%, 10%). Lower scanning resolutions are simulated by keeping every n-th laser beam with increasing step widths n. For each iteration step, high-resolution CSMs (0.01 m2 cells) are derived and assessed regarding their coverage relative to a seamless CSM derived from the original point cloud, standard deviation of elevation and mean elevation. Reducing the resolution to, e.g., 25% still leads to a coverage of >90% and a mean CSM elevation of >96% of measured crop height. CSM types (maximum elevation or 90th-percentile elevation) react differently to reduced scanning resolutions in different crops (variety, density). The results can help to assess the trade-off between CSM quality and minimum requirements regarding equipment and capturing set-up. PMID:25521383

  19. Effects of reduced terrestrial LiDAR point density on high-resolution grain crop surface models in precision agriculture.

    PubMed

    Hämmerle, Martin; Höfle, Bernhard

    2014-12-16

    3D geodata play an increasingly important role in precision agriculture, e.g., for modeling in-field variations of grain crop features such as height or biomass. A common data capturing method is LiDAR, which often requires expensive equipment and produces large datasets. This study contributes to the improvement of 3D geodata capturing efficiency by assessing the effect of reduced scanning resolution on crop surface models (CSMs). The analysis is based on high-end LiDAR point clouds of grain crop fields of different varieties (rye and wheat) and nitrogen fertilization stages (100%, 50%, 10%). Lower scanning resolutions are simulated by keeping every n-th laser beam with increasing step widths n. For each iteration step, high-resolution CSMs (0.01 m2 cells) are derived and assessed regarding their coverage relative to a seamless CSM derived from the original point cloud, standard deviation of elevation and mean elevation. Reducing the resolution to, e.g., 25% still leads to a coverage of >90% and a mean CSM elevation of >96% of measured crop height. CSM types (maximum elevation or 90th-percentile elevation) react differently to reduced scanning resolutions in different crops (variety, density). The results can help to assess the trade-off between CSM quality and minimum requirements regarding equipment and capturing set-up.

  20. Effects of reduced terrestrial LiDAR point density on high-resolution grain crop surface models in precision agriculture.

    PubMed

    Hämmerle, Martin; Höfle, Bernhard

    2014-01-01

    3D geodata play an increasingly important role in precision agriculture, e.g., for modeling in-field variations of grain crop features such as height or biomass. A common data capturing method is LiDAR, which often requires expensive equipment and produces large datasets. This study contributes to the improvement of 3D geodata capturing efficiency by assessing the effect of reduced scanning resolution on crop surface models (CSMs). The analysis is based on high-end LiDAR point clouds of grain crop fields of different varieties (rye and wheat) and nitrogen fertilization stages (100%, 50%, 10%). Lower scanning resolutions are simulated by keeping every n-th laser beam with increasing step widths n. For each iteration step, high-resolution CSMs (0.01 m2 cells) are derived and assessed regarding their coverage relative to a seamless CSM derived from the original point cloud, standard deviation of elevation and mean elevation. Reducing the resolution to, e.g., 25% still leads to a coverage of >90% and a mean CSM elevation of >96% of measured crop height. CSM types (maximum elevation or 90th-percentile elevation) react differently to reduced scanning resolutions in different crops (variety, density). The results can help to assess the trade-off between CSM quality and minimum requirements regarding equipment and capturing set-up. PMID:25521383

  1. Changes in whole grain polyphenols and antioxidant activity of six sorghum genotypes under different irrigation treatments.

    PubMed

    Wu, Gangcheng; Johnson, Stuart K; Bornman, Janet F; Bennett, Sarita J; Fang, Zhongxiang

    2017-01-01

    Sorghum grain containing elevated polyphenolic antioxidant content may provide foods with benefits to human health. A study was undertaken to determine the potential role of irrigation on the content of polyphenols and antioxidant levels in sorghum grain. Bound, free and total polyphenols were investigated in six diverse sorghum genotypes grown under either full irrigation or a deficit irrigation regime. Results showed genotype, irrigation and their interaction had a significant effect on polyphenols and antioxidant activity (P⩽0.05). The deficit irrigation treatment significantly increased polyphenol content and antioxidant activity compared to the full irrigation treatment. Of the six genotypes Shawaya black short 1 and IS1311C (brown) showed the highest polyphenols levels and antioxidant activity. Therefore, both irrigation treatments and genotype need to be considered by sorghum breeders and farmers during sorghum production to produce grain with the required levels of polyphenolics and antioxidant activity for targeted end-use. PMID:27507466

  2. Production and characterization of activated carbons from cereal grains

    SciTech Connect

    Venkatraman, A.; Walawender, W.P.; Fan, L.T.

    1996-12-31

    The term, activated carbon, is a generic name for a family of carbonaceous materials with well-developed porosities and consequently, large adsorptive capacities. Activated carbons are increasingly being consumed worldwide for environmental applications such as separation of volatiles from bulk gases and purification of water and waste-water streams. The global annual production is estimated to be around 300 million kilograms, with a rate of increase of 7% each year. Activated carbons can be prepared from a variety of raw materials. Approximately, 60% of the activated carbons generated in the United States is produced from coal; 20%, from coconut shells; and the remaining 20% from wood and other sources of biomass. The pore structure and properties of activated carbons are influenced by the nature of the starting material and the initial physical and chemical conditioning as well as the process conditions involved in its manufacture. The porous structures of charcoals and activated carbons obtained by the carbonization of kernels have been characterized.

  3. Presynaptic Active Zone Density during Development and Synaptic Plasticity.

    PubMed

    Clarke, Gwenaëlle L; Chen, Jie; Nishimune, Hiroshi

    2012-01-01

    Neural circuits transmit information through synapses, and the efficiency of synaptic transmission is closely related to the density of presynaptic active zones, where synaptic vesicles are released. The goal of this review is to highlight recent insights into the molecular mechanisms that control the number of active zones per presynaptic terminal (active zone density) during developmental and stimulus-dependent changes in synaptic efficacy. At the neuromuscular junctions (NMJs), the active zone density is preserved across species, remains constant during development, and is the same between synapses with different activities. However, the NMJ active zones are not always stable, as exemplified by the change in active zone density during acute experimental manipulation or as a result of aging. Therefore, a mechanism must exist to maintain its density. In the central nervous system (CNS), active zones have restricted maximal size, exist in multiple numbers in larger presynaptic terminals, and maintain a constant density during development. These findings suggest that active zone density in the CNS is also controlled. However, in contrast to the NMJ, active zone density in the CNS can also be increased, as observed in hippocampal synapses in response to synaptic plasticity. Although the numbers of known active zone proteins and protein interactions have increased, less is known about the mechanism that controls the number or spacing of active zones. The following molecules are known to control active zone density and will be discussed herein: extracellular matrix laminins and voltage-dependent calcium channels, amyloid precursor proteins, the small GTPase Rab3, an endocytosis mechanism including synaptojanin, cytoskeleton protein spectrins and β-adducin, and a presynaptic web including spectrins. The molecular mechanisms that organize the active zone density are just beginning to be elucidated.

  4. Inheritance of grain polyphenol oxidase (PPO) activity in multiple wheat (Triticum aestivum L.) genetic backgrounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain polyphenol oxidase (PPO) activity can cause discoloration of wheat (Triticum aestivum L.) food products. Five crosses (PI 117635/Antelope; Fielder/NW03681; Fielder/Antelope; NW07OR1070/Antelope; NW07OR1066/OR2050272H) were selected to study the genetic inheritance of PPO activity. STS marker...

  5. Understanding diffusion and density anomaly in a coarse-grained model for water confined between hydrophobic walls.

    PubMed

    de los Santos, Francisco; Franzese, Giancarlo

    2011-12-01

    We study, by Monte Carlo simulations, a coarse-grained model of a water monolayer between hydrophobic walls at partial hydration, with a wall-to-wall distance of about 0.5 nm. We analyze how the diffusion constant parallel to the walls, D(∥), changes and correlates to the phase diagram of the system. We find a locus of D(∥) maxima and a locus of D(∥) minima along isotherms, with lines of constant D(∥) resembling the melting line of bulk water. The two loci of D(∥) extrema envelope the line of temperatures of density maxima at constant P. We show how these loci are related to the anomalous volume behavior due to the hydrogen bonds. At much lower T, confined water becomes subdiffusive, and we discuss how this behavior is a consequence of the increased correlations among water molecules when the hydrogen bond network develops. Within the subdiffusive region, although translations are largely hampered, we observe that the hydrogen bond network can equilibrate, and its rearrangement is responsible for the appearance of density minima along isobars. We clarify that the minima are not necessarily related to the saturation of the hydrogen bond network.

  6. A modified ferrous oxidation-xylenol orange assay for lipoxygenase activity in rice grains.

    PubMed

    Timabud, Tarinee; Sanitchon, Jirawat; Pongdontri, Paweena

    2013-12-01

    Ferrous oxidation-xylenol orange assay reagent was reformulated by using spectral analysis of ferric-xylenol orange complex to detect low concentrations of lipoxygenase rice grain products. Reducing the levels of ferrous sulphate and xylenol orange in the FOX reagent enabled the detection of low concentrations of hydroperoxy fatty acid derived from lipoxygenase activity in the range of 0.1-1.5 μM. Protein, substrate and time courses of the modified FOX assay were studied to determine lipoxygenase activity in rice grain. The assay was also applicable as a high throughput technique for comparisons of lipoxygenase activity from various rice varieties. This has important implications for rapid screening for low-lipoxygenase containing rice cultivars in rice breeding program and grain quality during storage.

  7. Stored-grain insect population commingling densities in wheat and corn from pilot-scale bucket elevator boots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain elevator boot and pit areas facilitate the commingling of insects with the grain moving through the elevator leg. A removable boot was developed to facilitate residual grain removal and preservation in the boot and to quantify the commingling magnitude as a function of stored-product insect de...

  8. Activated carbon from pyrolysis of brewer's spent grain: Production and adsorption properties.

    PubMed

    Vanreppelen, Kenny; Vanderheyden, Sara; Kuppens, Tom; Schreurs, Sonja; Yperman, Jan; Carleer, Robert

    2014-06-20

    Brewer's spent grain is a low cost residue generated by the brewing industry. Its chemical composition (high nitrogen content 4.35 wt.%, fibres, etc.) makes it very useful for the production of added value in situ nitrogenised activated carbon. The composition of brewer's spent grain revealed high amounts of cellulose (20.8 wt.%), hemicellulose (48.78 wt.%) and lignin (11.3 wt.%). The fat, ethanol extractives and ash accounted for 8.17 wt.%, 4.7 wt.% and 3.2 wt.%, respectively. Different activated carbons were produced in a lab-scale pyrolysis/activation reactor by applying several heat and steam activation profiles on brewer's spent grain. Activated carbon yields from 16.1 to 23.6 wt.% with high N-contents (> 2 wt.%) were obtained. The efficiency of the prepared activated carbons for phenol adsorption was studied as a function of different parameters: pH, contact time and carbon dosage relative to two commercial activated carbons. The equilibrium isotherms were described by the non-linear Langmuir and Freundlich models, and the kinetic results were fitted using the pseudo-first-order model and the pseudo-second-order model. The feasibility of an activated carbon production facility (onsite and offsite) that processes brewer's spent grain for different input feeds is evaluated based on a techno-economic model for estimating the net present value. Even though the model assumptions start from a rather pessimistic scenario, encouraging results for a profitable production of activated carbon using brewer's spent grain are obtained. PMID:25012859

  9. Activated carbon from pyrolysis of brewer's spent grain: Production and adsorption properties.

    PubMed

    Vanreppelen, Kenny; Vanderheyden, Sara; Kuppens, Tom; Schreurs, Sonja; Yperman, Jan; Carleer, Robert

    2014-07-01

    Brewer's spent grain is a low cost residue generated by the brewing industry. Its chemical composition (high nitrogen content 4.35 wt.%, fibres, etc.) makes it very useful for the production of added value in situ nitrogenised activated carbon. The composition of brewer's spent grain revealed high amounts of cellulose (20.8 wt.%), hemicellulose (48.78 wt.%) and lignin (11.3 wt.%). The fat, ethanol extractives and ash accounted for 8.17 wt.%, 4.7 wt.% and 3.2 wt.%, respectively. Different activated carbons were produced in a lab-scale pyrolysis/activation reactor by applying several heat and steam activation profiles on brewer's spent grain. Activated carbon yields from 16.1 to 23.6 wt.% with high N-contents (> 2 wt.%) were obtained. The efficiency of the prepared activated carbons for phenol adsorption was studied as a function of different parameters: pH, contact time and carbon dosage relative to two commercial activated carbons. The equilibrium isotherms were described by the non-linear Langmuir and Freundlich models, and the kinetic results were fitted using the pseudo-first-order model and the pseudo-second-order model. The feasibility of an activated carbon production facility (onsite and offsite) that processes brewer's spent grain for different input feeds is evaluated based on a techno-economic model for estimating the net present value. Even though the model assumptions start from a rather pessimistic scenario, encouraging results for a profitable production of activated carbon using brewer's spent grain are obtained.

  10. Coarse-grained density functional theories for metallic alloys: Generalized coherent-potential approximations and charge-excess functional theory

    NASA Astrophysics Data System (ADS)

    Bruno, Ezio; Mammano, Francesco; Fiorino, Antonino; Morabito, Emanuela V.

    2008-04-01

    The class of the generalized coherent-potential approximations (GCPAs) to the density functional theory (DFT) is introduced within the multiple scattering theory formalism with the aim of dealing with ordered or disordered metallic alloys. All GCPA theories are based on a common ansatz for the kinetic part of the Hohenberg-Kohn functional and each theory of the class is specified by an external model concerning the potential reconstruction. Most existing DFT implementations of CPA-based theories belong to the GCPA class. The analysis of the formal properties of the density functional defined by GCPA theories shows that it consists of marginally coupled local contributions. Furthermore, it is shown that the GCPA functional does not depend on the details of the charge density and that it can be exactly rewritten as a function of the appropriate charge multipole moments to be associated with each lattice site. A general procedure based on the integration of the qV laws is described that allows for the explicit construction of the same function. The coarse-grained nature of the GCPA density functional implies a great deal of computational advantages and is connected with the O(N) scalability of GCPA algorithms. Moreover, it is shown that a convenient truncated series expansion of the GCPA functional leads to the charge-excess functional (CEF) theory [E. Bruno , Phys. Rev. Lett. 91, 166401 (2003)], which here is offered in a generalized version that includes multipolar interactions. CEF and the GCPA numerical results are compared with status of art linearized augmented plane wave (LAPW) full-potential density functional calculations for 62 bcc- and fcc-based ordered CuZn alloys, in all the range of concentrations. Two facts clearly emerge from these extensive tests. In the first place, the discrepancies between GCPA and CEF results are always within the numerical accuracy of the calculations, both for the site charges and the total energies. In the second place, the

  11. Coarse-grained simulations of an ionic liquid-based capacitor: I. Density, ion size, and valency effects.

    PubMed

    Breitsprecher, Konrad; Košovan, Peter; Holm, Christian

    2014-07-16

    We introduce a hierarchy of generic coarse-grained models of ionic liquids of increasing complexity. We use them in molecular dynamics simulations to study the differential capacitance of a capacitor consisting of an ionic liquid between two planar electrodes. The primary goal is to explain the complex dependence of the differential capacitance Cd on the electrode potential U in simple terms, e.g. in terms of the size and valency of the ions. For this purpose we introduce the symmetric model A, which qualitatively reproduces the Cd(U) dependence predicted by the mean-field theory but also reveals strong quantitative deviations. We further introduce size asymmetry in model A by increasing the cation size. In model B we vary the cation valency, keeping the sizes of both ions constant. We show that simultaneous increases in size and valency may compensate for each other, leading to a Cd(U) very similar to that for the symmetric case. We interpret distinct features in Cd(U) on the basis of the density profiles of the ions and charge density profiles. We focus on the first two ion layers at the electrode, and demonstrate that the polarization of the ionic liquid proceeds through replacement of one ion type by the other, in contrast to the simple increase in ion concentrations typical for dilute systems. The understanding gained for the simple models serves as a reference for interpretation of complex effects of ion size, valency and shape. This is carried through in part II (a separate article) where we show how the planar shape of ions in model C brings new features to the Cd(U) curve and also to the polarization mechanism.

  12. Stability and electronic structure of the low- Σ grain boundaries in CdTe: a density functional study

    DOE PAGES

    Park, Ji-Sang; Kang, Joongoo; Yang, Ji-Hui; Metzger, Wyatt; Wei, Su-Huai

    2015-01-15

    Using first-principles density functional calculations, we investigate the relative stability and electronic structure of the grain boundaries (GBs) in zinc-blende CdTe. Among the low-Σ-value symmetric tilt Σ3 (111), Σ3 (112), Σ5 (120), and Σ5 (130) GBs, we show that the Σ3 (111)GB is always the most stable due to the absence of dangling bonds and wrong bonds. The Σ5 (120) GBs, however, are shown to be more stable than the Σ3 (112) GBs, even though the former has a higher Σ value, and the latter is often used as a model system to study GB effects in zinc-blende semiconductors. Furthermore,more » we find that although containing wrong bonds, the Σ5 (120) GBs are electrically benign due to the short wrong bond lengths, and thus are not as harmful as the Σ3 (112) GBs also having wrong bonds but with longer bond lengths.« less

  13. Phenolic acids and antioxidant activity of distillers dried grains with solubles (DDGS) as compared with corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sample sets of ground corn and the corresponding distillers dried grains with solubles (DDGS) were collected from three commercial plants in Iowa. Phenolic acids were analyzed by high performance liquid chromatography coupled with diode array and/or mass spectrometry. The antioxidant activity was ...

  14. Significantly enhanced critical current density in nano-MgB2 grains rapidly formed at low temperature with homogeneous carbon doping

    NASA Astrophysics Data System (ADS)

    Liu, Yongchang; Lan, Feng; Ma, Zongqing; Chen, Ning; Li, Huijun; Barua, Shaon; Patel, Dipak; Shahriar, M.; Hossain, Al; Acar, S.; Kim, Jung Ho; Xue Dou, Shi

    2015-05-01

    High performance MgB2 bulks using carbon-coated amorphous boron as a boron precursor were fabricated by Cu-activated sintering at low temperature (600 °C, below the Mg melting point). Dense nano-MgB2 grains with a high level of homogeneous carbon doping were formed in these MgB2 samples. This type of microstructure can provide a stronger flux pinning force, together with depressed volatility and oxidation of Mg owing to the low-temperature Cu-activated sintering, leading to a significant improvement of critical current density (Jc) in the as-prepared samples. In particular, the value of Jc for the carbon-coated (Mg1.1B2)Cu0.05 sample prepared here is even above 1 × 105 A cm-2 at 20 K, 2 T. The results herein suggest that the combination of low-temperature Cu-activated sintering and employment of carbon-coated amorphous boron as a precursor could be a promising technique for the industrial production of practical MgB2 bulks or wires with excellent Jc, as the carbon-coated amorphous boron powder can be produced commercially at low cost, while the addition of Cu is very convenient and inexpensive.

  15. Irradiation-induced grain growth in nanocrystalline reduced activation ferrite/martensite steel

    SciTech Connect

    Liu, W. B.; Chen, L. Q.; Zhang, C. Yang, Z. G.; Ji, Y. Z.; Zang, H.; Shen, T. L.

    2014-09-22

    In this work, we investigate the microstructure evolution of surface-nanocrystallized reduced activation ferrite/martensite steels upon high-dose helium ion irradiation (24.3 dpa). We report a significant irradiation-induced grain growth in the irradiated buried layer at a depth of 300–500 nm, rather than at the peak damage region (at a depth of ∼840 nm). This phenomenon can be explained by the thermal spike model: minimization of the grain boundary (GB) curvature resulting from atomic diffusion in the cascade center near GBs.

  16. The synthesis of lamellar nano MgB2 grains with nanoimpurities, flux pinning centers and their significantly improved critical current density.

    PubMed

    Ma, Zongqing; Liu, Yongchang; Cai, Qi

    2012-03-21

    MgB(2) superconductors with unique microstructures were rapidly fabricated at low temperatures, and exhibited significantly improved critical current density (J(c)). According to the microstructure observations, the prepared samples consisted of lamellar nano MgB(2) grains with many embedded nanoimpurities (about 10 nm). The formation of these lamellar nano MgB(2) grains is associated with the presence of a local Mg-Cu liquid at sintering temperatures as low as 575 °C. The ball milling treatment of the original powders also plays a positive role in the growth of lamellar grains. Based on an analysis of the relationship between resistivity and temperature, the lamellar nano MgB(2) grains in the prepared sample possess better grain connectivity than the typical morphology of MgB(2) samples prepared by traditional high-temperature sintering. Furthermore, the presence of many nano MgB(2) grain boundaries and nano impurities in the prepared sample can obviously increase the flux pinning centers in accordance with the analysis of flux pinning behavior. Both factors mentioned above contribute to the significant improvement in J(c) from low field to relative high field. The method developed in the present work is an effective and low-cost way to further enhance J(c) in MgB(2) superconductors across a wide range of applied magnetic fields without using expensive nanometer-sized dopants.

  17. The interaction of hydrogen with the {010} surfaces of Mg and Fe olivine as models for interstellar dust grains: a density functional theory study.

    PubMed

    Downing, C A; Ahmady, B; Catlow, C R A; de Leeuw, N H

    2013-07-13

    There is no consensus as yet to account for the significant presence of water on the terrestrial planets, but suggested sources include direct hydrogen adsorption from the parent molecular cloud after the planets' formation, and delivery of hydrous material via comets or asteroids external to the zone of the terrestrial planets. Alternatively, a more recent idea is that water may have directly adsorbed onto the interstellar dust grains involved in planetary formation. In this work, we use electronic structure calculations based on the density functional theory to investigate and compare the bulk and {010} surface structures of the magnesium and iron end-members of the silicate mineral olivine, namely forsterite and fayalite, respectively. We also report our results on the adsorption of atomic hydrogen at the mineral surfaces, where our calculations show that there is no activation barrier to the adsorption of atomic hydrogen at these surfaces. Furthermore, different surface sites activate the atom to form either adsorbed hydride or proton species in the form of hydroxy groups on the same surface, which indicates that these mineral surfaces may have acted as catalytic sites in the immobilization and reaction of hydrogen atoms to form dihydrogen gas or water molecules. PMID:23734054

  18. The interaction of hydrogen with the {010} surfaces of Mg and Fe olivine as models for interstellar dust grains: a density functional theory study

    PubMed Central

    Downing, C. A.; Ahmady, B.; Catlow, C. R. A.; de Leeuw, N. H.

    2013-01-01

    There is no consensus as yet to account for the significant presence of water on the terrestrial planets, but suggested sources include direct hydrogen adsorption from the parent molecular cloud after the planets’ formation, and delivery of hydrous material via comets or asteroids external to the zone of the terrestrial planets. Alternatively, a more recent idea is that water may have directly adsorbed onto the interstellar dust grains involved in planetary formation. In this work, we use electronic structure calculations based on the density functional theory to investigate and compare the bulk and {010} surface structures of the magnesium and iron end-members of the silicate mineral olivine, namely forsterite and fayalite, respectively. We also report our results on the adsorption of atomic hydrogen at the mineral surfaces, where our calculations show that there is no activation barrier to the adsorption of atomic hydrogen at these surfaces. Furthermore, different surface sites activate the atom to form either adsorbed hydride or proton species in the form of hydroxy groups on the same surface, which indicates that these mineral surfaces may have acted as catalytic sites in the immobilization and reaction of hydrogen atoms to form dihydrogen gas or water molecules. PMID:23734054

  19. Ionospheric Electron Density during Magnetically Active Times over Istanbul

    NASA Astrophysics Data System (ADS)

    Naz Erbaş, Bute; Kaymaz, Zerefsan; Ceren Moral, Aysegul; Emine Ceren Kalafatoglu Eyiguler, R. A..

    2016-07-01

    In this study, we analyze electron density variations over Istanbul using Dynasonde observations during the magnetically active times. In order to perform statistical analyses, we first determined magnetic storms and magnetospheric substorm intervals from October 2012 to October 2015 using Kyoto's magnetic index data. Corresponding ionospheric parameters, such as critical frequency of F2 region (foF2), maximum electron density height (hmF2), total electron density (TEC) etc. were retrieved from Dynasonde data base at Istanbul Technical University's Space Weather Laboratory. To understand the behavior of electron density during the magnetically active times, we remove the background quiet time variations first and then quantify the anomalies. In this presentation, we will report results from our preliminary analyses from the selected cases corresponding to the strong magnetic storms. Initial results show lower electron densities at noon times and higher electron densities in the late afternoon toward sunset times when compared to the electron densities of magnetically quiet times. We also compare the results with IRI and TIEGCM ionospheric models in order to understand the physical and dynamical causes of these variations. During the presentation we will also discuss the role of these changes during the magnetically active times on the GPS communications through ionosphere.

  20. Increasing total and biologically active chromium in wheat grain and spinach by spraying with chromium salts

    SciTech Connect

    Vicini, F.A.; Ellis, B.G.

    1981-06-01

    Recently, chromium has been shown to be necessary for glucose metabolism in man. But most plant species greatly restrict the uptake of Cr. This study was conducted to determine if both total and biologically active Cr could be increased in wheat grain or spinach by spraying the plants with either Cr/sub 2/(SO/sub 4/)/sub 3/ or Cr-EDTA. Concentrations of Cr in wheat grain were about doubled in a greenhouse experiment by spraying with either Cr source. Biologically active Cr (estimated by extraction with ethanol or NH/sub 4/OH) was increased from about 40 to greater than 50% of total Cr when wheat was sprayed with Cr salts. Total Cr in spinach leaves was increased by as much as 10-fold by spraying, with the sulfate source being more effective than the EDTA.

  1. Activity of carbon dioxide fixation by anthers and leaves of cereal grains

    SciTech Connect

    Kirichenko, E.B.; Chernyad'ev, I.I.; Doman, N.G.; Talibullina, K.K.; Voronkova, T.V.

    1986-05-01

    This paper gives a comparative evaluation of the photosynthetic activity of anthers and flag leaves in winter wheat, rye, and triticale. The content of chlorophylls in anthers and leaves was determined. The activity of /sup 14/CO/sub 2/ fixation by anthers and leaf disks was determined by the radiometric method in a chamber floating on mercury under standard exposure conditions (0.1% concentration of /sup 14/CO/sub 2/, illumination of 15,000 1x, temperature of 23 C). Analyses were conducted in three replications and the results of typical biological experiments are cited. Data show that chlorophyll is actively synthesized in the anthers of cereal grains.

  2. Characterization of mutagenic activity in grain-based coffee-substitute blends and instant coffees

    SciTech Connect

    Johansson, M.A.E.; Knize, M.G.; Felton, J.S.; Jagerstad, M.

    1994-06-01

    Several grain-based coffee-substitute blends and instant coffees showed a mutagenic response in the Ames/Salmonella test using TA98, YG1024 and YG1O29 with metabolic activation. The beverage powders contained 150 to 500 TA98 and 1150 to 4050 YG1024 revertant colonies/gram, respectively. The mutagenic activity in the beverage powders was shown to be stable to heat and the products varied in resistance to acid nitrite treatment. Characterization of the mutagenic activity, using HPLC-and the Ames test of the collected fractions, showed the coffee-substitutes and instant coffees contain several mutagenic compounds, which are most likely aromatic amines.

  3. The Dynamic Density Bottle: A Make-and-Take, Guided Inquiry Activity on Density

    ERIC Educational Resources Information Center

    Kuntzleman, Thomas S.

    2015-01-01

    An activity is described wherein students observe dynamic floating and sinking behavior of plastic pieces in various liquids. The liquids and solids are all contained within a plastic bottle; the entire assembly is called a "density bottle". After completing a series of experiments that guides students to think about the relative…

  4. Origin of recombination activity at small angle grain boundaries in multicrystalline silicon using multi-seed casting growth method

    NASA Astrophysics Data System (ADS)

    Kojima, Takuto; Tachibana, Tomihisa; Ohshita, Yoshio; Prakash, Ronit R.; Sekiguchi, Takashi; Yamaguchi, Masafumi

    2015-08-01

    The effect of misorientation on the recombination activity of tilt small angle grain boundaries was studied by temperature-dependent electron beam induced current (EBIC) analyses of artificially induced grain boundaries in multicrystal grown by casting from multiple seeds. For small misorientation, there is no significant difference in the recombination of grain boundaries at the middle of a grown ingot, whereas moderate contamination on grain boundaries caused changes in the EBIC contrast, especially at room temperature. The EBIC contrast of moderately contaminated grain boundaries at room temperature has a peak at a misorientation of ∼3°, and for misorientation θ > 6°, the recombinative nature diminishes with increasing misorientation. The results indicate differences in the gettering ability of small angle grain boundaries.

  5. Anti-inflammatory Activity of Grains of Paradise (Aframomum melegueta Schum) Extract

    PubMed Central

    2015-01-01

    The ethanolic extract of grains of paradise (Aframomum melegueta Schum, Zingiberaceae) has been evaluated for inhibitory activity on cyclooxygenase-2 (COX-2) enzyme, in vivo for the anti-inflammatory activity and expression of several pro-inflammatory genes. Bioactivity-guided fractionation showed that the most active COX-2 inhibitory compound in the extract was [6]-paradol. [6]-Shogaol, another compound from the extract, was the most active inhibitory compound in pro-inflammatory gene expression assays. In a rat paw edema model, the whole extract reduced inflammation by 49% at 1000 mg/kg. Major gingerols from the extract [6]-paradol, [6]-gingerol, and [6]-shogaol reduced inflammation by 20, 25 and 38%. respectively when administered individually at a dose of 150 mg/kg. [6]-Shogaol efficacy was at the level of aspirin, used as a positive control. Grains of paradise extract has demonstrated an anti-inflammatory activity, which is in part due to the inhibition of COX-2 enzyme activity and expression of pro-inflammatory genes. PMID:25293633

  6. Dust Grains and the Luminosity of Circumnuclear Water Masers in Active Galaxies

    NASA Technical Reports Server (NTRS)

    Collison, Alan J.; Watson, William D.

    1995-01-01

    In previous calculations for the luminosities of 22 GHz water masers, the pumping is reduced and ultimately quenched with increasing depth into the gas because of trapping of the infrared (approximately equals 30-150 micrometers), spectral line radiation of the water molecule. When the absorption (and reemission) of infrared radiation by dust grains is included, we demonstrate that the pumping is no longer quenched but remains constant with increasing optical depth. A temperature difference between the grains and the gas is required. Such conditions are expected to occur, for example, in the circumnuclear masing environments created by X-rays in active galaxies. Here, the calculated 22 GHz maser luminosities are increased by more than an order of magnitude. Application to the well-studied, circumnuclear masing disk in the galaxy NGC 4258 yields a maser luminosity near that inferred from observations if the observed X-ray flux is assumed to be incident onto only the inner surface of the disk.

  7. Antioxidant Activity of Individual Steryl Ferulates from Various Cereal Grain Sources.

    PubMed

    Zhu, Dan; Sánchez-Ferrer, Antoni; Nyström, Laura

    2016-02-26

    Steryl ferulates (SFs) are a subclass of bioactive lipids contributing to the health-promoting effects of whole grains. Most related studies focus on γ-oryzanol, a SF mixture from rice, since individual steryl ferulates are not commercially available. There is little evidence that individual SFs may vary in their bioactivity. The aim of this study was to evaluate the antioxidant activity of eight individual SFs by determining their radical scavenging capacity. Additional molecular properties of the individual SFs were determined by molecular simulation in order to identify correlations with their antioxidant activities. Our study demonstrates that individual SFs exhibit 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and superoxide anion radical scavenging abilities with subtle differences that were highly dependent on the kind of reaction taking place. The grouping of SFs by principle component analysis was mainly attributed to molecular properties, not antioxidant activities. Solvation energy was significantly correlated with some experimental observations. To our knowledge, this is the first study to evaluate the antioxidant activity of eight individual steryl ferulates from different sources. Results of this work will provide better insight into the antioxidant activity of SFs and the health benefits of whole grains.

  8. Reduction of pyruvate orthophosphate dikinase activity is associated with high temperature-induced chalkiness in rice grains.

    PubMed

    Wang, Zhen-mei; Li, Hai-xia; Liu, Xiong-feng; He, Ying; Zeng, Han-lai

    2015-04-01

    Global warming affects both rice (Oryza sativa) yields and grain quality. Rice chalkiness due to high temperature during grain filling would lower the grain quality. The biochemical and molecular mechanisms responsible for the increased occurrence of chalkiness under high temperature are not fully understood. Previous research suggested that cytosolic pyruvate orthophosphate dikinase (cyPPDK, EC 2.7.9.1) in rice modulates carbon metabolism. The objective of this study was to determine the relationship between cyPPDK and high temperature-induced chalkiness. High temperature treatments were applied during the grain filling of two rice cultivars (9311 and TXZ-25) which had different sensitivity of chalkiness to high temperature. Chalkiness was increased significantly under high temperature treatment, especially for TXZ-25. A shortened grain filling duration and a decreased grain weight in both cultivars were caused by high temperature treatment. A reduction in PPDK activities due to high temperature was observed during the middle and late grain filling periods, accompanied by down regulated cyPPDK mRNA and protein levels. The temperature effects on the developmental regulation of PPDK activity were confirmed at transcription, translation and post-translational levels. PPDK activities were insensitive to variation in PPDK levels, suggesting the rapid phosphorylation mechanism of this protein. The two varieties showed similar responses to the high temperature treatment in both PPDK activities and chalkiness. We concluded that high temperature-induced chalkiness was associated with the reduction of PPDK activity.

  9. Flume Experiments on the Influence of Salmon Spawning Density on Grain Stability and Bedload Transport in Gravel-bed Streams

    NASA Astrophysics Data System (ADS)

    Buxton, T. H.

    2015-12-01

    Salmon spawning in streams involves the female salmon digging a pit in the bed where she deposits eggs for fertilization before covering them with gravel excavated from the next pit upstream. Sequences of pit excavation and filling winnow fines, loosen sediment, and move bed material into a tailspill mound resembling the shape of a dune. Research suggests salmonid nests (redds) destabilize streambeds by reducing friction between loosened grains and converging flow that elevates shear stress on redd topography. However, bed stability may be enhanced by form drag from redds in clusters that lower shear stress on the granular bed, but this effect will vary with the proportion of the bed surface that is occupied by redds (P). I used simulated redds and water-worked ("unspawned") beds in a laboratory flume to evaluate these competing influences on grain stability and bedload transport rates with P=0.12, 0.34, and 0.41. Results indicate that competence (largest-grain) and reference transport rate estimates of critical conditions for particle entrainment inversely relate to P. Bedload transport increased as exponential functions of P and excess boundary shear stress. Therefore, redd form drag did not overcome the destabilizing effects of spawning. Instead, grain mobility and bedload transport increased with P because larger areas of the bed were composed of relatively loose, unstable grains and redd topography that experienced elevated shear stress. Consequently, the presence of redds in fish-bearing streams likely reduces the effects of sedimentation from landscape disturbance on stream habitats that salmon use for reproduction.

  10. Density functional theory metadynamics of silver, caesium and palladium diffusion at β-SiC grain boundaries

    NASA Astrophysics Data System (ADS)

    Rabone, Jeremy; López-Honorato, Eddie

    2015-03-01

    The use of silicon carbide in coated nuclear fuel particles relies on this materials impermeability towards fission products under normal operating conditions. Determining the underlying factors that control the rate at which radionuclides such as Silver-110m and Caesium-137 can cross the silicon carbide barrier layers, and at which fission products such as palladium could compromise or otherwise alter the nature of this layer, are of paramount importance for the safety of this fuel. To this end, DFT-based metadynamics simulations are applied to the atomic diffusion of silver, caesium and palladium along a Σ5 grain boundary and to palladium along a carbon-rich Σ3 grain boundary in cubic silicon carbide at 1500 K. For silver, the calculated diffusion coefficients lie in a similar range (7.04 × 10-19-3.69 × 10-17 m2 s-1) as determined experimentally. For caesium, the calculated diffusion rates are very much slower (3.91 × 10-23-2.15 × 10-21 m2 s-1) than found experimentally, suggesting a different mechanism to the simulation. Conversely, the calculated atomic diffusion of palladium is very much faster (7.96 × 10-11-7.26 × 10-9 m2 s-1) than the observed penetration rate of palladium nodules. This points to the slow dissolution and rapid regrowth of palladium nodules as a possible ingress mechanism in addition to the previously suggested migration of entire nodules along grain boundaries. The diffusion rate of palladium along the Σ3 grain boundary was calculated to be slightly slower (2.38 × 10-11-8.24 × 10-10 m2 s-1) than along the Σ5 grain boundary. Rather than diffusing along the precise plane of the boundary, the palladium atom moves through the bulk layer immediately adjacent to the boundary as there is greater freedom to move.

  11. High density of (pseudo) periodic twin-grain boundaries in molecular beam epitaxy-grown van der Waals heterostructure: MoTe2/MoS2

    NASA Astrophysics Data System (ADS)

    Diaz, Horacio Coy; Ma, Yujing; Chaghi, Redhouane; Batzill, Matthias

    2016-05-01

    Growth of transition metal dichalcogenide heterostructures by molecular beam epitaxy (MBE) promises synthesis of artificial van der Waals materials with controllable layer compositions and separations. Here, we show that MBE growth of 2H-MoTe2 monolayers on MoS2 substrates results in a high density of mirror-twins within the films. The grain boundaries are tellurium deficient, suggesting that Te-deficiency during growth causes their formation. Scanning tunneling microscopy and spectroscopy reveal that the grain boundaries arrange in a pseudo periodic "wagon wheel" pattern with only ˜2.6 nm repetition length. Defect states from these domain boundaries fill the band gap and thus give the monolayer an almost metallic property. The band gap states pin the Fermi-level in MoTe2 and thus determine the band-alignment in the MoTe2/MoS2 interface.

  12. IPS observations of heliospheric density structures associated with active regions

    NASA Technical Reports Server (NTRS)

    Hick, P.; Jackson, B. V.; Altrock, R.; Woan, G.; Slater, G.

    1996-01-01

    Interplanetary scintillation (IPS) measurements of the 'disturbance factor' g, obtained with the Cambridge (UK) array can be used to explore the heliospheric density structure. We have used these data to construct synoptic (Carrington) maps, representing the large-scale enhancements of the g-factor in the inner heliosphere. These maps emphasize the stable corotating, rather than the transient heliospheric density enhancements. We have compared these maps with Carrington maps of Fe XIV observations National Solar Observatory ((NSO), Sacramento Peak) and maps based on Yohkoh Soft X-Ray Telescope (SXT) X-ray observations. Our results indicate that the regions of enhanced g tend to map to active regions rather than the current sheet. The implication is that act ve regions are the dominant source of the small-scale (approximately equal 200 km) density variations present in the quiet solar wind.

  13. Identification of accumulation, density and grain size bias in the regional climate model MAR over the Greenland ice sheet using in-situ and remotely sensed data

    NASA Astrophysics Data System (ADS)

    Alexander, P. M.; Tedesco, M.; Steiner, N.; Marshall, H.; Luthcke, S. B.; Fettweis, X.

    2011-12-01

    The Modèle Atmosphérique Regional (MAR) has been used in multiple studies to investigate recent and long-term changes to the Surface Mass Balance (SMB) of the Greenland ice sheet. Quantifying the magnitude of changes in ice sheet SMB is important for understanding the magnitude of reported recent ice sheet mass loss, and predicting future changes that can contribute to sea level rise. Regional climate models such as MAR have provided estimates of the SMB. Due to sparse observational data, there are large uncertainties in quantities important for accurate SMB estimates, such as accumulation, bare ice extent, and surface albedo, for example. An ongoing analysis of MAR grain size, density, and accumulation bias is being undertaken as part of a broader effort to assimilate satellite data within MAR. The ultimate goal of this project is to improve the accuracy of SMB estimates. Here we report results from an initial comparison between MAR data and in-situ profiles and meteorological data collected at the Summit station in Greenland. Results suggest that the model underestimates grain size and density in the upper portion of the snowpack. We also compare MAR estimates of accumulation with trends of mass change derived from the GRACE satellites and with elevation changes estimated from spaceborne and airborne missions, such as CRYOSAT, ICESAT and ICEBRIDGE. An investigation of MAR parameterizations reveals potential solutions for improving the albedo and grain size schemes. Further investigation of satellite-derived grain size and albedo is planned, which will reveal whether locally observed bias is indeed present on a larger scale.

  14. High-density genetic linkage map construction and QTL mapping of grain shape and size in the wheat population Yanda1817 × Beinong6.

    PubMed

    Wu, Qiu-Hong; Chen, Yong-Xing; Zhou, Sheng-Hui; Fu, Lin; Chen, Jiao-Jiao; Xiao, Yao; Zhang, Dong; Ouyang, Shu-Hong; Zhao, Xiao-Jie; Cui, Yu; Zhang, De-Yun; Liang, Yong; Wang, Zhen-Zhong; Xie, Jing-Zhong; Qin, Jin-Xia; Wang, Guo-Xin; Li, De-Lin; Huang, Yin-Lian; Yu, Mei-Hua; Lu, Ping; Wang, Li-Li; Wang, Ling; Wang, Hao; Dang, Chen; Li, Jie; Zhang, Yan; Peng, Hui-Ru; Yuan, Cheng-Guo; You, Ming-Shan; Sun, Qi-Xin; Wang, Ji-Rui; Wang, Li-Xin; Luo, Ming-Cheng; Han, Jun; Liu, Zhi-Yong

    2015-01-01

    High-density genetic linkage maps are necessary for precisely mapping quantitative trait loci (QTLs) controlling grain shape and size in wheat. By applying the Infinium iSelect 9K SNP assay, we have constructed a high-density genetic linkage map with 269 F 8 recombinant inbred lines (RILs) developed between a Chinese cornerstone wheat breeding parental line Yanda1817 and a high-yielding line Beinong6. The map contains 2431 SNPs and 128 SSR & EST-SSR markers in a total coverage of 3213.2 cM with an average interval of 1.26 cM per marker. Eighty-eight QTLs for thousand-grain weight (TGW), grain length (GL), grain width (GW) and grain thickness (GT) were detected in nine ecological environments (Beijing, Shijiazhuang and Kaifeng) during five years between 2010-2014 by inclusive composite interval mapping (ICIM) (LOD ≥ 2.5). Among which, 17 QTLs for TGW were mapped on chromosomes 1A, 1B, 2A, 2B, 3A, 3B, 3D, 4A, 4D, 5A, 5B and 6B with phenotypic variations ranging from 2.62% to 12.08%. Four stable QTLs for TGW could be detected in five and seven environments, respectively. Thirty-two QTLs for GL were mapped on chromosomes 1B, 1D, 2A, 2B, 2D, 3B, 3D, 4A, 4B, 4D, 5A, 5B, 6B, 7A and 7B, with phenotypic variations ranging from 2.62% to 44.39%. QGl.cau-2A.2 can be detected in all the environments with the largest phenotypic variations, indicating that it is a major and stable QTL. For GW, 12 QTLs were identified with phenotypic variations range from 3.69% to 12.30%. We found 27 QTLs for GT with phenotypic variations ranged from 2.55% to 36.42%. In particular, QTL QGt.cau-5A.1 with phenotypic variations of 6.82-23.59% was detected in all the nine environments. Moreover, pleiotropic effects were detected for several QTL loci responsible for grain shape and size that could serve as target regions for fine mapping and marker assisted selection in wheat breeding programs.

  15. Pichia anomala in grain biopreservation.

    PubMed

    Olstorpe, Matilda; Passoth, Volkmar

    2011-01-01

    Cereal grain is a major component of food and feed in large parts of the world. The microbial flora on cereal grains may interfere with hygiene and storage stability, palatability and bioavailability of minerals and proteins may depend on the composition of the microbial population. Therefore, it is of primary interest to control the microbial species present on cereal grain. Inoculation of the biocontrol yeast Pichia anomala to cereal feed grain improved feed hygiene by reduction of moulds and Enterobacteriaceae, and enhanced the nutritional value by increasing the protein content and reducing the concentration of the antinutritional compound phytate. P. anomala strains showed a high phytase activity, for some strains also considerable extracellular phytase activity was observed. A certain maximum in biomass concentration was never exceeded indicating cell density induced growth inhibition of P. anomala.

  16. Characteristics and Development of Leucine Transport Activity in the Scutellum of Germinating Barley Grain 1

    PubMed Central

    Sopanen, Tuomas; Uuskallio, Marjukka; Nyman, Seija; Mikola, Juhani

    1980-01-01

    Scutella separated from grains of Himalaya barley after germination for 3 days rapidly took up l-leucine from aerated incubation media; with 1 millimolar leucine the rate varied between 4 and 14 micromoles per gram per hour and the pH optimum was at 3.5 to 5, both depending on buffer composition and prewashing time. The rate of the uptake increased with increasing concentration of leucine in a complex manner, which could be interpreted as multiphasic kinetics with apparent Km values of 3.4 and 15.5 millimolar below and above 3 millimolar leucine, respectively. The uptake took place against a concentration difference (highest estimated ratio 270: 1) and was strongly inhibited by dinitrophenol. Uptake was apparently due to active transport requiring metabolic energy. The development of the uptake activity during germination was studied using Pirkka barley. A low activity was present in the scutella of ungerminated grains. It began to increase after 6 hours imbibition, and the increase was biphasic, the major changes occurring during days 0 to 3 and 4 to 6. The total increase was about 20-fold. The regulation of the development was studied by allowing separated embryos to germinate on agar gel. The increase of uptake activity was strongly inhibited by inhibitors of RNA or protein synthesis. Increase did not require the presence of the embryo proper, and was not affected by gibberellic or abscisic acid. Removal of the endosperm greatly accelerated the increase of uptake activity, and the presence of 5 or 20 millimolar glutamine counteracted the removal of the endosperm. The results suggest that the availability of glutamine or amino acids in general in the endosperm may regulate the development or the activity of the transport system. PMID:16661169

  17. Enhancement of wheat grain antioxidant activity by solid state fermentation with Grifola spp.

    PubMed

    Postemsky, Pablo; Curvetto, Néstor

    2014-05-01

    Grifola frondosa, Grifola gargal, and Grifola sordulenta are edible and medicinal mushrooms with antioxidant properties. To obtain wheat flour (Wf ) with a higher antioxidant activity than the one exhibited by regular Wf, solid state fermentation (SSF) of wheat grains with mycelia of those Grifola spp. was used to obtain biotransformed wheat grain (BWG) flour. The methanolic extract of control Wf and BWG flour of G. gargal, G. sordulenta, and G. frondosa (GfWG, GgWG, and GsWG, respectively) were studied for their radical scavenging (RS) activity against 2,2-diphenyl-1-picrylhydracyl (DPPH) and their Fe(III) reducing power (RP). The values for RS-EC50 decreased in BWG flour, therefore presenting a higher antioxidant activity: GgWG (0.56 mg/mL), GfWG (0.81 mg/mL), and GsWG (5.80 mg/mL) in comparison to Wf (57.60 mg/mL). The antioxidant content for this RS activity in terms of ascorbic acid content (RS-EQAA) was highest in GfWG, followed by GgWG and GsWG (71.73, 14.46, and 3.02 mg/g, respectively) and lowest in Wf (0.25 mg/g). The RP-EC50 values in GgWG, GfWG, and GsWG were low (0.55, 0.64, and 4.20 mg/mL, respectively) with respect to Wf (55.00 mg/mL). Compared with Wf (0.56 mg/g), the RP capacity in terms of ascorbic acid content (RP-EQAA) was very high in GfWG (193.67 mg/g) followed by GgWG and GsWG (31.42 and 8.74 mg/g, respectively). The high content in gallic acid equivalents was consistent with RS-EQ(AA) and RP-EQ(AA) contents. TLC revealed that antioxidant activity in BWG could be related to the presence of phenolic compounds. Thus, a valuable food alternative can easily be obtained with wheat grains, that is, by markedly increasing their antioxidant value through SSF with Grifola spp.

  18. Abscisic acid and aldehyde oxidase activity in maize ear leaf and grain relative to post-flowering photosynthetic capacity and grain-filling rate under different water/nitrogen treatments.

    PubMed

    Qin, Shujun; Zhang, Zongzheng; Ning, Tangyuan; Ren, Shizhong; Su, Licheng; Li, Zengjia

    2013-09-01

    This study investigated changes in leaf abscisic acid (ABA) concentrations and grain ABA concentrations in two maize cultivars and analyzed the following relationships under different water/nitrogen treatments: leaf ABA concentrations and photosynthetic parameters; leaf ABA concentrations and grain ABA concentrations; leaf/grain ABA concentrations and grain-filling parameters; and aldehyde oxidase (AO, EC 1.2.3.1) activities and ABA concentrations. The ear leaf average AO activities and ABA concentrations were lower in the controlled release urea treatments compared with the conventional urea treatments. The average AO activities in the grains were higher in the controlled release urea treatments, and the ABA concentrations were significantly increased at 11-30 DAF. The Pn and ABA concentrations in ear leaves were negatively correlated. And the Gmean were positively correlated with the grain ABA concentrations at 11-30 DAF and negatively correlated with the leaf ABA concentrations at 20 and 40-50 DAF. The grain ABA concentrations and leaf ABA concentrations were positively correlated. Thus, the Gmean were closely related to the AO activities and to the ear leaf and grain ABA concentrations. As compared to other treatments, the subsoiling and controlled release urea treatment promoted the uptake of water and nitrogen by maize, increased the photosynthetic capacity of the ear leaves, increased the grain-filling rate, and improved the movement of photosynthetic assimilates toward the developing grains. In the cultivar Z958, higher ABA concentrations in grains at 11-30 DAF and lower ABA concentrations in ear leaves during the late grain-filling stage, resulted in higher grain-filling rate and increased accumulation of photosynthetic products (relative to the cultivar D3). PMID:23770596

  19. Abscisic acid and aldehyde oxidase activity in maize ear leaf and grain relative to post-flowering photosynthetic capacity and grain-filling rate under different water/nitrogen treatments.

    PubMed

    Qin, Shujun; Zhang, Zongzheng; Ning, Tangyuan; Ren, Shizhong; Su, Licheng; Li, Zengjia

    2013-09-01

    This study investigated changes in leaf abscisic acid (ABA) concentrations and grain ABA concentrations in two maize cultivars and analyzed the following relationships under different water/nitrogen treatments: leaf ABA concentrations and photosynthetic parameters; leaf ABA concentrations and grain ABA concentrations; leaf/grain ABA concentrations and grain-filling parameters; and aldehyde oxidase (AO, EC 1.2.3.1) activities and ABA concentrations. The ear leaf average AO activities and ABA concentrations were lower in the controlled release urea treatments compared with the conventional urea treatments. The average AO activities in the grains were higher in the controlled release urea treatments, and the ABA concentrations were significantly increased at 11-30 DAF. The Pn and ABA concentrations in ear leaves were negatively correlated. And the Gmean were positively correlated with the grain ABA concentrations at 11-30 DAF and negatively correlated with the leaf ABA concentrations at 20 and 40-50 DAF. The grain ABA concentrations and leaf ABA concentrations were positively correlated. Thus, the Gmean were closely related to the AO activities and to the ear leaf and grain ABA concentrations. As compared to other treatments, the subsoiling and controlled release urea treatment promoted the uptake of water and nitrogen by maize, increased the photosynthetic capacity of the ear leaves, increased the grain-filling rate, and improved the movement of photosynthetic assimilates toward the developing grains. In the cultivar Z958, higher ABA concentrations in grains at 11-30 DAF and lower ABA concentrations in ear leaves during the late grain-filling stage, resulted in higher grain-filling rate and increased accumulation of photosynthetic products (relative to the cultivar D3).

  20. Silica nanoparticles in E ring ice grains as an indicator for hydrothermal activities at Enceladus

    NASA Astrophysics Data System (ADS)

    Postberg, F.; Hsu, H. W.; Sekine, Y.

    2013-09-01

    Since 2004 the Cosmic Dust Analyser (CDA) on board the Cassini spacecraft detects nano-meter sized dust particles, so called stream particles, in the Saturnian system. Recently it has been shown that they are released from E ring ice grains in which they were previously embedded [1]. As a consequence the nanograins must have been generated at Saturns active moon Enceladus which feeds the E ring by its spectacular jets of vapour and ice grains. Liquid water below the moons icy crust is known to be the dominant source of these jets [2, 3]. New results from CDA presented here indicate that stream particles actually are nano-silica grains. The most prominent geological process which produces nano-phase silica are hydrothermal rock-water interactions. This process has recently been intensely studied for hydrothermal systems on Earth [e.g. 4, 5]. The measured concentration, composition and size range observed at in the Saturnian system precisely matches a hydrothermal synthesis origin. Thus, we propose nano-colloidal silica to be present at mMol concentrations in Enceladus' subsurface waters. We were able to reproduce the proposed hydrothermal serpentinisation processes in a geochemical long term experiment in the laboratory. As there are no alternative formation scenarios which are in agreement with the CDA observations our results indicate ongoing rock-water interactions inside Enceladus at temperatures clearly exceeding 100°C. We discuss implications for Enceladus geochemistry, like salinity, possible ranges of temperature and pH, as well as the mineral composition of the Enceladian rock core.

  1. Biologically active low density lipoprotein in human peripheral lymph.

    PubMed Central

    Reichl, D; Myant, N B; Brown, M S; Goldstein, J L

    1978-01-01

    We have compared the ability of human serum and peripheral lymph to suppress the activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase), to activate cholesteryl ester synthesis, and to compete with 125I-labeled low density lipoprotein (LDL) for binding to LDL receptors in cultured human fibroblasts. Whole lymph was active in all three tests and the activity per unit volume in lymph was approximately equal to 1/10th that in serum. All three biologic activities in lymph were confined to the d less than 1.063 g/ml fraction. Whole lymph had no significant effect on HMG-CoA reductase activity in fibroblasts from a patient with homozygous familial hypercholesterolemia, whose cells lack LDL receptors. The LDL-like biologic activity per unit mass of immunologically active apoprotein B was approximately the same in lymph as in serum. The current data indicate that functionally active LDL is present in lymph and that the concentration of this lipoprotein is approximately equal to 1/10th that in serum. PMID:201669

  2. Active minimization of energy density in three-dimensional enclosures

    NASA Technical Reports Server (NTRS)

    Sommerfeldt, Scott D.

    1996-01-01

    The objective of this study was to further investigate and develop a novel approach for actively controlling the sound field in enclosures that is based on the acoustic energy density. Typically the acoustic field in an enclosure has been controlled by minimizing the sum of the squared pressures from several microphones distributed throughout the enclosure. The approach investigated in this study involved minimizing the acoustic energy density at the sensor locations, rather than the squared pressure. Research previous to this study in a simple one-dimensional enclosure showed that improved global attenuation of the acoustic field is often obtained by minimizing the energy density, rather than the pressure. The current study built on the previous research by extending the method of controlling the acoustic energy density to three-dimensional enclosures. The study was intended to help establish if improved control can still be expected in a more general enclosure. The study was designed to be both analytical/numerical and experimental in nature.

  3. Thermally activated switching at long time scales in exchange-coupled magnetic grains

    NASA Astrophysics Data System (ADS)

    Almudallal, Ahmad M.; Mercer, J. I.; Whitehead, J. P.; Plumer, M. L.; van Ek, J.; Fal, T. J.

    2015-10-01

    Rate coefficients of the Arrhenius-Néel form are calculated for thermally activated magnetic moment reversal for dual layer exchange-coupled composite (ECC) media based on the Langer formalism and are applied to study the sweep rate dependence of M H hysteresis loops as a function of the exchange coupling I between the layers. The individual grains are modeled as two exchange-coupled Stoner-Wohlfarth particles from which the minimum energy paths connecting the minimum energy states are calculated using a variant of the string method and the energy barriers and attempt frequencies calculated as a function of the applied field. The resultant rate equations describing the evolution of an ensemble of noninteracting ECC grains are then integrated numerically in an applied field with constant sweep rate R =-d H /d t and the magnetization calculated as a function of the applied field H . M H hysteresis loops are presented for a range of values I for sweep rates 105Oe /s ≤R ≤1010Oe /s and a figure of merit that quantifies the advantages of ECC media is proposed. M H hysteresis loops are also calculated based on the stochastic Landau-Lifshitz-Gilbert equations for 108Oe /s ≤R ≤1010Oe /s and are shown to be in good agreement with those obtained from the direct integration of rate equations. The results are also used to examine the accuracy of certain approximate models that reduce the complexity associated with the Langer-based formalism and which provide some useful insight into the reversal process and its dependence on the coupling strength and sweep rate. Of particular interest is the clustering of minimum energy states that are separated by relatively low-energy barriers into "metastates." It is shown that while approximating the reversal process in terms of "metastates" results in little loss of accuracy, it can reduce the run time of a kinetic Monte Carlo (KMC) simulation of the magnetic decay of an ensemble of dual layer ECC media by 2 -3 orders of magnitude

  4. Iminosugar inhibitors of carbohydrate-active enzymes that underpin cereal grain germination and endosperm metabolism

    PubMed Central

    Andriotis, Vasilios M. E.; Rejzek, Martin; Rugen, Michael D.; Svensson, Birte; Smith, Alison M.; Field, Robert A.

    2016-01-01

    Starch is a major energy store in plants. It provides most of the calories in the human diet and, as a bulk commodity, it is used across broad industry sectors. Starch synthesis and degradation are not fully understood, owing to challenging biochemistry at the liquid/solid interface and relatively limited knowledge about the nature and control of starch degradation in plants. Increased societal and commercial demand for enhanced yield and quality in starch crops requires a better understanding of starch metabolism as a whole. Here we review recent advances in understanding the roles of carbohydrate-active enzymes in starch degradation in cereal grains through complementary chemical and molecular genetics. These approaches have allowed us to start dissecting aspects of starch degradation and the interplay with cell-wall polysaccharide hydrolysis during germination. With a view to improving and diversifying the properties and uses of cereal grains, it is possible that starch degradation may be amenable to manipulation through genetic or chemical intervention at the level of cell wall metabolism, rather than simply in the starch degradation pathway per se. PMID:26862201

  5. A coarse-grained model to study calcium activation of the cardiac thin filament

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Schwartz, Steven

    2015-03-01

    Familial hypertrophic cardiomyopathy (FHC) is one of the most common heart disease caused by genetic mutations. Cardiac muscle contraction and relaxation involve regulation of crossbridge binding to the cardiac thin filament, which regulates actomyosin interactions through calcium-dependent alterations in the dynamics of cardiac troponin (cTn) and tropomyosin (Tm). An atomistic model of cTn complex interacting with Tm has been studied by our group. A more realistic model requires the inclusion of the dynamics of actin filament, which is almost 6 times larger than cTn and Tm in terms of atom numbers, and extensive sampling of the model becomes very resource-demanding. By using physics-based protein united-residue force field, we introduce a coarse-grained model to study the calcium activation of the thin filament resulting from cTn's allosteric regulation of Tm dynamics on actin. The time scale is much longer than that of all-atom molecular dynamics simulation because of the reduction of the degrees of freedom. The coarse-grained model is a good template for studying cardiac thin filament mutations that cause FHC, and reduces the cost of computational resources.

  6. Effect of the morphology and grains size distribution of alumina ceramic mass on the green and fire density and shrinkage of moulders

    SciTech Connect

    Wojcik, M.A.; Sidor, J.; Kabaia, J.; Paiyz, J.; Purska, E.

    1996-10-01

    The successful fabrication of high alumina ceramics is a thorough preparation of the powders which depends on the various requirements of the different forming procedures. All of alumina used in these ceramics have defined ultimate crystal sizes, controlled grindability and green densities to ensure the very tight shrinkage tolerances which are critical for the sparking plug production process. Production practice shows that alumina grinding belong to very important unit operation. So, the effect of morphology and grains size distribution of alumina ceramic mass (ACM) obtained after grinding in rotary-vibration mill on the green and fire density and shrinkage of moulders are presented in this paper. The granulation parameters (d{sub 50}) of monodispersed product was selected according to its application in the production of sparking plugs.

  7. COMMUNICATION: Neuron network activity scales exponentially with synapse density

    NASA Astrophysics Data System (ADS)

    Brewer, G. J.; Boehler, M. D.; Pearson, R. A.; DeMaris, A. A.; Ide, A. N.; Wheeler, B. C.

    2009-02-01

    Neuronal network output in the cortex as a function of synapse density during development has not been explicitly determined. Synaptic scaling in cortical brain networks seems to alter excitatory and inhibitory synaptic inputs to produce a representative rate of synaptic output. Here, we cultured rat hippocampal neurons over a three-week period to correlate synapse density with the increase in spontaneous spiking activity. We followed the network development as synapse formation and spike rate in two serum-free media optimized for either (a) neuron survival (Neurobasal/B27) or (b) spike rate (NbActiv4). We found that while synaptophysin synapse density increased linearly with development, spike rates increased exponentially in developing neuronal networks. Synaptic receptor components NR1, GluR1 and GABA-A also increase linearly but with more excitatory receptors than inhibitory. These results suggest that the brain's information processing capability gains more from increasing connectivity of the processing units than increasing processing units, much as Internet information flow increases much faster than the linear number of nodes and connections.

  8. Neuron network activity scales exponentially with synapse density.

    PubMed

    Brewer, G J; Boehler, M D; Pearson, R A; DeMaris, A A; Ide, A N; Wheeler, B C

    2009-02-01

    Neuronal network output in the cortex as a function of synapse density during development has not been explicitly determined. Synaptic scaling in cortical brain networks seems to alter excitatory and inhibitory synaptic inputs to produce a representative rate of synaptic output. Here, we cultured rat hippocampal neurons over a three-week period to correlate synapse density with the increase in spontaneous spiking activity. We followed the network development as synapse formation and spike rate in two serum-free media optimized for either (a) neuron survival (Neurobasal/B27) or (b) spike rate (NbActiv4). We found that while synaptophysin synapse density increased linearly with development, spike rates increased exponentially in developing neuronal networks. Synaptic receptor components NR1, GluR1 and GABA-A also increase linearly but with more excitatory receptors than inhibitory. These results suggest that the brain's information processing capability gains more from increasing connectivity of the processing units than increasing processing units, much as Internet information flow increases much faster than the linear number of nodes and connections. PMID:19104141

  9. Fungi Isolated from Maize (Zea mays L.) Grains and Production of Associated Enzyme Activities.

    PubMed

    Abe, Camila Agnes Lumi; Faria, Carla Bertechini; de Castro, Fausto Fernandes; de Souza, Sandra Regina; dos Santos, Fabiane Cristina; da Silva, Cleiltan Novais; Tessmann, Dauri José; Barbosa-Tessmann, Ione Parra

    2015-07-07

    Filamentous fungi produce a great variety of enzymes, and research on their biotechnological potential has recently intensified. The objective of this work was to identify, at the species level, using DNA barcoding, 46 fungal isolates obtained from maize grains with rot symptoms. We also analyzed the production of extracellular amylases, cellulases, proteases and lipases of 33 of those fungal isolates. The enzymatic activities were evaluated by the formation of a clear halo or a white precipitate around the colonies in defined substrate media. The found fungi belong to the genera Talaromyces, Stenocarpella, Penicillium, Phlebiopsis, Cladosporium, Hyphopichia, Epicoccum, Trichoderma, Aspergillus, Irpex, Fusarium, Microdochium, Mucor and Sarocladium. In the genus Fusarium, the species Fusarium verticillioides was predominant and this genus presented the highest diversity, followed by the genera Aspergillus. The best genera for lipase production were Cladosporium and Penicillium; while Cladosporium, Aspergillus and Penicillium were best for cellulase activity; Hyphopichia, Aspergillus and Irpex for amylase activity; and Cladosporium and Sarocladium for proteases activity. In conclusion, a collection of fungi from maize seeds presenting rotten symptoms were obtained, among which exist important producers of hydrolases.

  10. Fungi Isolated from Maize (Zea mays L.) Grains and Production of Associated Enzyme Activities

    PubMed Central

    Lumi Abe, Camila Agnes; Bertechini Faria, Carla; Fernandes de Castro, Fausto; de Souza, Sandra Regina; dos Santos, Fabiane Cristina; Novais da Silva, Cleiltan; Tessmann, Dauri José; Barbosa-Tessmann, Ione Parra

    2015-01-01

    Filamentous fungi produce a great variety of enzymes, and research on their biotechnological potential has recently intensified. The objective of this work was to identify, at the species level, using DNA barcoding, 46 fungal isolates obtained from maize grains with rot symptoms. We also analyzed the production of extracellular amylases, cellulases, proteases and lipases of 33 of those fungal isolates. The enzymatic activities were evaluated by the formation of a clear halo or a white precipitate around the colonies in defined substrate media. The found fungi belong to the genera Talaromyces, Stenocarpella, Penicillium, Phlebiopsis, Cladosporium, Hyphopichia, Epicoccum, Trichoderma, Aspergillus, Irpex, Fusarium, Microdochium, Mucor and Sarocladium. In the genus Fusarium, the species Fusarium verticillioides was predominant and this genus presented the highest diversity, followed by the genera Aspergillus. The best genera for lipase production were Cladosporium and Penicillium; while Cladosporium, Aspergillus and Penicillium were best for cellulase activity; Hyphopichia, Aspergillus and Irpex for amylase activity; and Cladosporium and Sarocladium for proteases activity. In conclusion, a collection of fungi from maize seeds presenting rotten symptoms were obtained, among which exist important producers of hydrolases. PMID:26198227

  11. Active zones of mammalian neuromuscular junctions: formation, density, and aging

    PubMed Central

    Nishimune, Hiroshi

    2012-01-01

    Presynaptic active zones are synaptic vesicle release sites that playessential roles in the function and pathology of mammalian neuromuscular junctions (NMJs). The molecular mechanisms of active zone organization utilize presynaptic voltage-dependent calcium channels (VDCCs) in NMJs as scaffolding proteins. VDCCs interact extracellularly with the muscle-derived synapse organizer, laminin β2, and interact intracellularly with active zone-specific proteins, such as Bassoon, CAST/Erc2/ELKS2alpha, ELKS, Piccolo, and RIMs. These molecular mechanisms are supported by studies in P/Q- and N-type VDCCs double-knockout mice, and they are consistent with the pathological conditions of Lambert-Eaton myasthenic syndrome and Pierson syndrome, which are caused by autoantibodies against VDCCs or by a laminin β2 mutation. During normal postnatal maturation, NMJs maintain the density of active zones, while NMJs triple their size. However, active zones become impaired during aging. Propitiously, muscle exercise ameliorates the active zone impairment in aged NMJs, which suggests the potential for therapeutic strategies. PMID:23252894

  12. IPS activity observed as a precursor of solar induced terrestrial activity. [solar wind density fluctuations

    NASA Technical Reports Server (NTRS)

    Cronyn, W. M.; Shawhan, S. D.; Rickard, J. J.; Mitchell, D. G.; Roelof, E. C.; Gotwols, B. L.

    1978-01-01

    A radio telescope designed to exploit the interplanetary scintillation (IPS) technique and locate, map, and track solar wind disturbances which result in geomagnetic disturbances, thereby providing a forecast capability, is described. Preliminary results from operation of the telescope include: (1) evidence for a precursor signal in the IPS activity with a 1-2 day lead time with respect to density enhancements which frequently give rise to geomagnetic activity; (2) detection of a spectral broadening signature which also serves as a precursor of geomagnetic activity; (3) out-of-the-ecliptic plasma density enhancements which were not detected by near-Earth, ecliptic plane spacecraft; (4) detection of 12 corotating density enhancements;(5) detection of over 80 sources which give detectable scintillation of which 45 have been used for detailed synoptic analysis and 9 for spectral analysis; and (6) measurement of 0-lag coefficient of 0.56 between density and IPS activity enhancements.

  13. A Method to Increase Current Density in a Mono Element Internal Tin Processed Superconductor Utilizing Zr Oxide to Refine Grain Size

    SciTech Connect

    Bruce A. Zeitlin, Eric Gregory

    2008-04-07

    The effect of Oxygen on (Nb1Zr)3Sn multifilament conductors manufactured by the Mono Element Internal Tin (MEIT) process was explored to improve the current density by refining the grain size. This followed work first done by General Electric on the Nb3Sn tape process. Techniques to fabricate the more difficult Nb1Zr composites are described and allowed fabrication of long lengths of .254 mm diameter wire from an 88.9 mm diameter billet. Oxygen was incorporated through the use of SnO2 mixed with tin powder and incorporated into the core. These were compared to samples with Ti+Sn and Cu+Sn cores. Heat treatments covered the range of 700 C to 1000 C. Current density vs. H, grain size, and reaction percentages are provided for the materials tested. The Oxygen gave superior results in the temperature range of 815-1000 C. It also stabilized the filament geometry of the array in comparison to the other additions at the higher temperatures. At 815 C a peak in layer Jc yielded values of 2537 A/mm2 at 12 T and 1353 A/mm2 at 15T, 8-22% and 30-73% greater respectively than 700 C values. Results with Oxygen at high temperature show the possibility of high speed continuous reaction of the composite versus the current batch or react in place methods. In general the Ti additions gave superior results at the lower reaction temperature. Future work is suggested to determine if the 815 C reaction temperature can lead to higher current density in high tin (Nb1Zr+Ox)3Sn conductors. A second technique incorporated oxygen directly into the Nb1Zr rods through heat treatment with Nb2O5 at 1100 C for 100 hours in vacuum prior to extrusion. The majority of the filaments reduced properly in the composite but some local variations in hardness led to breakage at smaller diameters.

  14. Activities of fructan- and sucrose-metabolizing enzymes in wheat stems subjected to water stress during grain filling.

    PubMed

    Yang, Jianchang; Zhang, Jianhua; Wang, Zhiqing; Zhu, Qingsen; Liu, Lijun

    2004-12-01

    This study investigated if a controlled water deficit during grain filling of wheat (Triticum aestivum L.) could accelerate grain filling by facilitating the remobilization of carbon reserves in the stem through regulating the enzymes involved in fructan and sucrose metabolism. Two high lodging-resistant wheat cultivars were grown in pots and treated with either a normal (NN) or high amount of nitrogen (HN) at heading time. Plants were either well-watered (WW) or water-stressed (WS) from 9 days post anthesis until maturity. Leaf water potentials markedly decreased at midday as a result of water stress but completely recovered by early morning. Photosynthetic rate and zeatin + zeatin riboside concentrations in the flag leaves declined faster in WS plants than in WW plants, and they decreased more slowly with HN than with NN when soil water potential was the same, indicating that the water deficit enhanced, whereas HN delayed, senescence. Water stress, both at NN and HN, facilitated the reduction in concentration of total nonstructural carbohydrates (NSC) and fructans in the stems but increased the sucrose level there, promoted the re-allocation of pre-fixed (14)C from the stems to grains, shortened the grain-filling period, and accelerated the grain-filling rate. Grain weight and grain yield were increased under the controlled water deficit when HN was applied. Fructan exohydrolase (FEH; EC 3.2.1.80) and sucrose phosphate synthase (SPS; EC 2.4.1.14) activities were substantially enhanced by water stress and positively correlated with the total NSC and fructan remobilization from the stems. Acid invertase (EC 3.2.1.26) activity was also enhanced by the water stress and associated with the change in fructan concentration, but not correlated with the total NSC remobilization and (14)C increase in the grains. Sucrose:sucrose fructosyltransferase (EC 2.4.1.99) activity was inhibited by the water stress and negatively correlated with the remobilization of carbon reserves

  15. Factors affecting laboratory bioassays with diatomaceous earth on stored wheat: effect of insect density, grain quantity, and cracked kernel containment.

    PubMed

    Kavallieratos, Nickolas G; Athanassiou, Christos G; Mpakou, Flora D; Mpassoukou, Argyro E

    2007-10-01

    Laboratory bioassays were carried out to evaluate the effect of insect density (10, 30, 60, and 100 adults), wheat quantity (10, 30, 60, and 100 g), and cracked kernel containment (5, 15, 30, and 50%) on the efficacy of diatomaceous earth (DE). Three beetle species, Sitophilus oryzae (L.), Rhyzopertha dominica (F.), and Tribolium confusum Jacquelin du Val, as well as two DE formulations, Insecto and SilicoSec, and one DE enhanced with pyrethrum, PyriSec (all commercially available) were tested. In the first two series of bioassays, the three DE formulations were applied at three dose rates, 500, 1000 and 1,500 ppm. In the third series, the dose rates used were 500 and 1,000 ppm. Dead adults were counted 14 d later. For insect density, wheat quantity, and cracked kernel containment, significant differences were noted in mortality levels of the tested species among the three DE formulations and among doses. No significant differences were noted in the mortality levels among the four adult densities of any of the insects tested. The increase of wheat quantity used in the bioassays increased significantly adult mortality of T. confusum. The increase of cracked wheat containment decreased significantly adult mortality of S. oryzae.

  16. OsMAPK6, a mitogen-activated protein kinase, influences rice grain size and biomass production.

    PubMed

    Liu, Shuying; Hua, Lei; Dong, Sujun; Chen, Hongqi; Zhu, Xudong; Jiang, Jun'e; Zhang, Fang; Li, Yunhai; Fang, Xiaohua; Chen, Fan

    2015-11-01

    Grain size is an important agronomic trait in determining grain yield. However, the molecular mechanisms that determine the final grain size are not well understood. Here, we report the functional analysis of a rice (Oryza sativa L.) mutant, dwarf and small grain1 (dsg1), which displays pleiotropic phenotypes, including small grains, dwarfism and erect leaves. Cytological observations revealed that the small grain and dwarfism of dsg1 were mainly caused by the inhibition of cell proliferation. Map-based cloning revealed that DSG1 encoded a mitogen-activated protein kinase (MAPK), OsMAPK6. OsMAPK6 was mainly located in the nucleus and cytoplasm, and was ubiquitously distributed in various organs, predominately in spikelets and spikelet hulls, consistent with its role in grain size and biomass production. As a functional kinase, OsMAPK6 interacts strongly with OsMKK4, indicating that OsMKK4 is likely to be the upstream MAPK kinase of OsMAPK6 in rice. In addition, hormone sensitivity tests indicated that the dsg1 mutant was less sensitive to brassinosteroids (BRs). The endogenous BR levels were reduced in dsg1, and the expression of several BR signaling pathway genes and feedback-inhibited genes was altered in the dsg1 mutant, with or without exogenous BRs, indicating that OsMAPK6 may contribute to influence BR homeostasis and signaling. Thus, OsMAPK6, a MAPK, plays a pivotal role in grain size in rice, via cell proliferation, and BR signaling and homeostasis. PMID:26366992

  17. Variation in the interaction between alleles of HvAPETALA2 and microRNA172 determines the density of grains on the barley inflorescence

    PubMed Central

    Houston, Kelly; McKim, Sarah M.; Comadran, Jordi; Bonar, Nicola; Druka, Ilze; Uzrek, Nicola; Cirillo, Elisa; Guzy-Wrobelska, Justyna; Collins, Nicholas C.; Halpin, Claire; Hansson, Mats; Dockter, Christoph; Druka, Arnis; Waugh, Robbie

    2013-01-01

    Within the cereal grasses, variation in inflorescence architecture results in a conspicuous morphological diversity that in crop species influences the yield of cereal grains. Although significant progress has been made in identifying some of the genes underlying this variation in maize and rice, in the temperate cereals, a group that includes wheat, barley, and rye, only the dosage-dependent and highly pleiotropic Q locus in hexaploid wheat has been molecularly characterized. Here we show that the characteristic variation in the density of grains along the inflorescence, or spike, of modern cultivated barley (Hordeum vulgare) is largely the consequence of a perturbed interaction between microRNA172 and its corresponding binding site in the mRNA of an APELATA2 (AP2)-like transcription factor, HvAP2. We used genome-wide association and biparental mapping to identify HvAP2. By comparing inflorescence development and HvAP2 transcript abundance in an extreme dense-spike mutant and its nearly isogenic WT line, we show that HvAP2 turnover driven by microRNA 172 regulates the length of a critical developmental window that is required for elongation of the inflorescence internodes. Our data indicate that this heterochronic change, an altered timing of developmental events caused by specific temporal variation in the efficiency of HvAP2 turnover, leads to the striking differences in the size and shape of the barley spike. PMID:24065816

  18. Dust grains in the coma of 67P/Churyumov-Gerasimenko – link with surface properties and cometary activity

    NASA Astrophysics Data System (ADS)

    Capria, Maria Teresa; Ivanovski, Stavro; Zakharov, Vladimir; Capaccioni, Fabrizio; Filacchione, Gianrico; De Sanctis, Maria Cristina; rotundi, alessandra; della corte, vincenzo; Longobardo, Andrea; Palomba, Ernesto; colangeli, luigi; Bockelee-Morvan, Dominique; Érard, Stéphane; Leyrat, Cedric; VIRTIS, GIADA

    2016-10-01

    The imaging spectrometer VIRTIS and the dust analyzer GIADA, onboard Rosetta, made an extensive observation of the dust particles in the coma of the comet 67P/Churyumov-Gerasimenko. From the analysis of GIADA data, two different kind of particles have been revealed, compact and fluffy with different compositions and dynamical properties. Compact particles are characterized by densities of about 103 kg/m3, while fluffy particles have an almost fractal nature, with densities less than 1 kg/m3.In this work we present the initial results of a model linking the dust flux distribution, as obtained from a theoretical thermal nucleus model, with a model describing the dynamics of aspherical grains in the coma. The results are discussed in the context of the latest observations from VIRTIS and GIADA instruments.The 2D nucleus thermal model, when applied to the real shape of the comet, provides the size distribution and physical properties of the emitted grains at different times and location on the surface. The thermal model can simulate grains of various size distribution, composition and physical properties. This information is used as an input for the dust dynamical model that follows the emitted particles in the coma. The main source of heating is the solar illumination. In the dust dynamical model, the grain trajectory of emitted particles remains in a plane perpendicular to the rotational axis and the direction of illumination is taken to be in the same plane (i.e. does not cause transversal forces). The dust particles are assumed to be isothermal convex bodies and temperature changes only induce modest changes in the aerodynamic force (twice higher temperature changes aerodynamic force less than ~30%). This study reviews the theoretical values at which temperature difference starts to play a role on the dynamics. We discuss to what extent the particle's temperature affects the terminal velocities of the dust grains in the 67P coma in dependence on their mass and

  19. 76 FR 32988 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Grain...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-07

    ... published in the Federal Register on February 22, 2011 (76 FR 9815). Interested parties are encouraged to...; Grain Handling Facilities ACTION: Notice. SUMMARY: The Department of Labor (DOL) is submitting the..., ``Grain Handling Facilities (29 CFR 1910.272),'' to the Office of Management and Budget (OMB) for...

  20. Stability and electronic structure of the low- Σ grain boundaries in CdTe: a density functional study

    SciTech Connect

    Park, Ji-Sang; Kang, Joongoo; Yang, Ji-Hui; Metzger, Wyatt; Wei, Su-Huai

    2015-01-15

    Using first-principles density functional calculations, we investigate the relative stability and electronic structure of the grain boundaries (GBs) in zinc-blende CdTe. Among the low-Σ-value symmetric tilt Σ3 (111), Σ3 (112), Σ5 (120), and Σ5 (130) GBs, we show that the Σ3 (111)GB is always the most stable due to the absence of dangling bonds and wrong bonds. The Σ5 (120) GBs, however, are shown to be more stable than the Σ3 (112) GBs, even though the former has a higher Σ value, and the latter is often used as a model system to study GB effects in zinc-blende semiconductors. Furthermore, we find that although containing wrong bonds, the Σ5 (120) GBs are electrically benign due to the short wrong bond lengths, and thus are not as harmful as the Σ3 (112) GBs also having wrong bonds but with longer bond lengths.

  1. Silver and cesium diffusion dynamics at the β-SiC Σ5 grain boundary investigated with density functional theory molecular dynamics and metadynamics.

    PubMed

    Rabone, Jeremy; López-Honorato, Eddie; Van Uffelen, Paul

    2014-02-01

    The diffusion and release of silver-110m, a strong γ-radiation emitter, through silicon carbide in coated nuclear fuel particles has remained an unsolved topic since it was first observed 40 years ago. The challenge remains to explain why, contrary to other elements, silver is capable of escaping the ceramic diffusion barriers. The current work investigates the underlying differences in the diffusion of silver and cesium along a symmetric tilt Σ5 grain boundary of β-SiC through accelerated density functional theory molecular dynamics simulations. The energy barriers extracted from the simulations give diffusion coefficients that are in reasonable agreement with experiment for silver (2.19 × 10(-19) to 1.05 × 10(-17) m(2) s(-1)), but for cesium the equivalent calculated coefficients for this mechanism are much smaller (3.85 × 10(-23) to 2.15 × 10(-21) m(2) s(-1)) than those found experimentally. Analysis of the simulated structures and electron densities and comparisons with the calculations of other researchers suggest that diffusion of silver and cesium in β-SiC proceeds via different mechanisms. The mechanisms of cesium diffusion appear to be dominated by its relatively large size and repulsive interactions with the silicon and carbon atoms; β-SiC grain boundaries still offer higher energy barriers to diffusion. Silver, on the other hand, is not only smaller in size but, as we show for the first time, can also participate in weak bonding interactions with the host atoms where favorable geometries allow, thus reducing the energy barrier and enhancing the rate of diffusion. PMID:24422635

  2. Pyroclastic Eruptions in a Mars Climate Model: The Effects of Grain Size, Plume Height, Density, Geographical Location, and Season on Ash Distribution

    NASA Astrophysics Data System (ADS)

    Kerber, L. A.; Head, J. W.; Madeleine, J.; Wilson, L.; Forget, F.

    2010-12-01

    Pyroclastic volcanism has played a major role in the geologic history of the planet Mars. In addition to several highland patera features interpreted to be composed of pyroclastic material, there are a number of vast, fine-grained, friable deposits which may have a volcanic origin. The physical processes involved in the explosive eruption of magma, including the nucleation of bubbles, the fragmentation of magma, the incorporation of atmospheric gases, the formation of a buoyant plume, and the fall-out of individual pyroclasts has been modeled extensively for martian conditions [Wilson, L., J.W. Head (2007), Explosive volcanic eruptions on Mars: Tephra and accretionary lapilli formation, dispersal and recognition in the geologic record, J. Volcanol. Geotherm. Res. 163, 83-97]. We have further developed and expanded this original model in order to take into account differing temperature, pressure, and wind regimes found at different altitudes, at different geographic locations, and during different martian seasons. Using a well-established Mars global circulation model [LMD-GCM, Forget, F., F. Hourdin, R. Fournier, C. Hourdin, O. Talagrand (1999), Improved general circulation models of the martian atmosphere from the surface to above 80 km, J. Geophys. Res. 104, 24,155-24,176] we are able to link the volcanic eruption model of Wilson and Head (2007) to the spatially and temporally dynamic GCM temperature, pressure, and wind profiles to create three-dimensional maps of expected ash deposition on the surface. Here we present results exploring the effects of grain-size distribution, plume height, density of ash, latitude, season, and atmospheric pressure on the areal extent and shape of the resulting ash distribution. Our results show that grain-size distribution and plume height most strongly effect the distance traveled by the pyroclasts from the vent, while latitude and season can have a large effect on the direction in which the pyroclasts travel and the final shape

  3. Low-fat, increased fruit, vegetable, and grain dietary pattern, fractures, and bone mineral density: the Women's Health Initiative Dietary Modification Trial123

    PubMed Central

    Wactawski-Wende, Jean; Wu, LieLing; Rodabough, Rebecca J; Watts, Nelson B; Tylavsky, Frances; Freeman, Ruth; Hendrix, Susan; Jackson, Rebecca

    2009-01-01

    Background: The effects of dietary changes on osteoporosis, low bone density, and frequent falls are unestablished. Objective: We assessed the effect of the Women's Health Initiative Dietary Modification low-fat and increased fruit, vegetable, and grain intervention on incident hip, total, and site-specific fractures and self-reported falls, and, in a subset, on bone mineral density (BMD). Design: Postmenopausal women (n = 48,835) aged 50–79 y (18.6% of minority race-ethnicity) were randomly assigned to receive the Dietary Modification intervention (40%, n = 19,541) (daily goal: ≤20% of energy as fat, ≥5 servings of vegetables and fruit, and ≥6 servings of grains) or to a comparison group that received no dietary changes (60%; n = 29,294). Results: After a mean 8.1 y of follow-up, 215 women in the intervention group and 285 women in the comparison group (annualized rate: 0.14% and 0.12%, respectively) experienced a hip fracture (hazard ratio: 1.12; 95% CI: 0.94, 1.34; P = 0.21). The intervention group (n = 5423; annualized rate: 3.44%) had a lower rate of reporting ≥2 falls than did the comparison group (n = 8695; annualized rate: 3.67%) (HR: 0.92; 95% CI: 0.89, 0.96; P < 0.01). There was a significant interaction according to hormone therapy use; those in the comparison group receiving hormone therapy had the lowest incidence of hip fracture. In a subset of 3951 women, hip BMD at years 3, 6, and 9 was 0.4–0.5% lower in the intervention group than in the comparison group (P = 0.003). Conclusions: A low-fat and increased fruit, vegetable, and grain diet intervention modestly reduced the risk of multiple falls and slightly lowered hip BMD but did not change the risk of osteoporotic fractures. This trial was registered at clinicaltrials.gov as NCT00000611. PMID:19403636

  4. Total phenolic content and antioxidant activities of pomegranate juice and whey based novel beverage fermented by kefir grains.

    PubMed

    Sabokbar, Nayereh; Khodaiyan, Faramarz

    2016-01-01

    Mixture of pomegranate juice and whey was evaluated as a potential substrate for production of a novel beverage by kefir grains. The effects of two different variables, fermentation, temperature (19 and 25 °C) and kefir grain amount (5 %w/v and 8 %w/v), on total phenolic content (TPC) and antioxidant activities of beverage were examined during a fermentation time of 32 h. TPC and antioxidant activities including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, reducing power, inhibition effect upon linoleic acid autoxidation and inhibition effect upon ascorbate autoxidation increased significantly (p < 0.05) during fermentation, but metal chelating effect showed no significant difference. The highest increases were observed when the temperature of 25 °C and kefir grain amount of 8 %w/v were applied. Results proved antioxidant activities of beverages were desirable and fermentation by kefir grains has the ability to enhance these antioxidant activities, as compared with unfermented beverage. Also pomegranate juice and whey were suitable media for producing a novel dairy-juice beverage.

  5. A comparison of the levels of oil, carotenoids, and lipolytic enzyme activities in modern lines and hybrids of grain sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirteen modern commercial grain sorghum hybrids and five sorghum lines were extracted and the levels of oil and carotenoids were analyzed and compared. The same samples were also evaluated for lipolytic enzyme activity. The oil content in all eighteen samples ranged from 3.21 to 4.29 wt%. Beta c...

  6. Introduction to Agronomy, Grain Crops, Weeds and Controls. A Learning Activity Pac in Agricultural Education Courses in Wisconsin.

    ERIC Educational Resources Information Center

    Wisconsin State Dept. of Public Instruction, Madison. Div. of Instructional Services.

    This learning activity pac contains information to help the teachers of high school vocational agriculture in the instructional area of agronomy. Each of the two main sections, grain crops and weeds and controls, includes teacher and student units for the section lessons. Teacher units include special instructions--equipment needed (film…

  7. Neutron Activation Analysis of Single Grains Recovered by the Hayabusa Spacecraft

    NASA Technical Reports Server (NTRS)

    Ebihara, M.; Sekimoto, S.; Hamajima, Y.; Yamamoto, M.; Kumagai, K.; Oura, Y.; Shirai, N.; Ireland. T. R.; Kitajima, F.; Nagao, K.; Nakamura, T.; Naraoka, H.; Noguchi, T.; Okazaki, R.; Tsuchiyama, A.; Uesugi, M.; Yurimoto, H.; Zolensky, M. E.; Abe, M.; Fujimura, A.; Mukai, T.; Yada, T.

    2011-01-01

    The Hayabusa spacecraft was launched on May 9, 2003 and reached an asteroid Itokawa (25143 Itokawa) in September 2005. After accomplishing several scientific observations, the spacecraft tried to collect the surface material of Itokawa by touching down to the asteroid in November. The spacecraft was then navigated for the earth. In encountering several difficulties, Hayabusa finally returned to the earth on June 12, 2010 and the entry capsule was successfully recovered. Initially, a g-scale of solid material was aimed to be captured into the entry capsule. Although the sample collection was not perfectly performed, it was hoped that some extraterrestrial material was stored into the capsule. After careful and extensive examination, more than 1500 particles were recognized visibly by microscopes, most of which were eventually judged to be extraterrestrial, highly probably originated from Itokawa [1]. Several years before the launching of the Hayabusa spacecraft, the initial analysis team was officially formed under the selection panel at ISAS. As a member of this team, we have been preparing for the initial inspection of the returned material from many scientific viewpoints [2]. Once the recovered material had been confirmed to be much less than 1 g, a scheme for the initial analysis was updated accordingly [3]. In this study, we aim to analyze tiny single grains by instrumental neutron activation analysis (INAA). As the initial analysis is to be started in mid-January, 2011, some progress for the initial analysis using INAA is described here. Analytical procedure

  8. Critical current density behaviors across a grain boundary inclined to current with different angles in YBa2Cu3O7-δ bicrystal junctions

    NASA Astrophysics Data System (ADS)

    Tao, Hua; Wei-Wei, Xu; Zheng-Ming, Ji; Da-Yuan, Guo; Qing-Yun, Wang; Xiang-Rong, Ma; Rui-Yu, Liang

    2016-06-01

    The critical current density behaviors across a bicrystal grain boundary (GB) inclined to the current direction with different angles in YBa2Cu3O7-δ bicrystal junctions in magnetic fields are investigated. There are two main reasons for the difference in critical current density in junctions at different GB inclined angles in the same magnetic field: (i) the GB plane area determines the current carrying cross section; (ii) the vortex motion dynamics at the GB affects the critical current value when the vortex starts to move along the GB by Lorentz force. Furthermore, the vortex motion in a bicrystal GB is studied by investigating transverse (Hall) and longitudinal current-voltage characteristics (I-V xx and I-V xy ). It is found that the I-V xx curve diverges from linearity at a high driving current, while the I-V xy curve keeps nearly linear, which indicates the vortices inside the GB break out of the GB by Lorentz force. Project supported by the National Natural Science Foundation of China (Grant Nos. 61501222, 61371036, and 61571219) and the School Scientific Research Fund of Nanjing Institute of Technology, China (Grant Nos. YKJ201418).

  9. Density functional theory study of the influence of segregation of S or Fe impurities on electromigration in nano-grained copper interconnects

    SciTech Connect

    Shabalin, M.; Fuks, D.

    2015-05-21

    The reliability of the circuits in the modern microelectronic devices remains, during last decades, one of the key topics in research and gains an attention for improving the promising candidates for conductors. Improvement of materials for such applications can be obtained by both electronic and compositional optimization. Ab initio calculations using full potential linearized augmented plane wave method in density functional theory are applied to explain the reduction in electromigration effect in the vicinity of grain boundaries (GB) in nano-structured Cu due to the segregation of some additives to the GB. Several possible mechanisms are considered. It is demonstrated that S atoms segregated to GB of nano-structured Cu lead to the growth of effective mass of the electrons. This decreases the mobility of electrons in external electric field, and, correspondingly, the momentum that they may transfer to atoms in collisions. Fe atoms segregated to GB of Cu create new empty states at the top of the valance band. These non-occupied states may stimulate the current of holes when external electric field is applied to the system, creating the “hole wind” in the direction opposite to the current of electrons. Such “hole wind” will compensate the forces generated by the electron current and therefore will reduce the total momentum transfer between charge carriers and atoms. The calculated electron density maps show that S and Fe segregating to Cu GB increases the strength of covalent bonds reducing the diffusion of Cu atoms in the vicinity of GB.

  10. Critical current density behaviors across a grain boundary inclined to current with different angles in YBa2Cu3O7‑δ bicrystal junctions

    NASA Astrophysics Data System (ADS)

    Tao, Hua; Wei-Wei, Xu; Zheng-Ming, Ji; Da-Yuan, Guo; Qing-Yun, Wang; Xiang-Rong, Ma; Rui-Yu, Liang

    2016-06-01

    The critical current density behaviors across a bicrystal grain boundary (GB) inclined to the current direction with different angles in YBa2Cu3O7‑δ bicrystal junctions in magnetic fields are investigated. There are two main reasons for the difference in critical current density in junctions at different GB inclined angles in the same magnetic field: (i) the GB plane area determines the current carrying cross section; (ii) the vortex motion dynamics at the GB affects the critical current value when the vortex starts to move along the GB by Lorentz force. Furthermore, the vortex motion in a bicrystal GB is studied by investigating transverse (Hall) and longitudinal current–voltage characteristics (I–V xx and I–V xy ). It is found that the I–V xx curve diverges from linearity at a high driving current, while the I–V xy curve keeps nearly linear, which indicates the vortices inside the GB break out of the GB by Lorentz force. Project supported by the National Natural Science Foundation of China (Grant Nos. 61501222, 61371036, and 61571219) and the School Scientific Research Fund of Nanjing Institute of Technology, China (Grant Nos. YKJ201418).

  11. Effect of Grain Size on Bacterial Penetration, Reproduction, and Metabolic Activity in Porous Glass Bead Chambers

    PubMed Central

    Sharma, Pramod K.; McInerney, Michael J.

    1994-01-01

    We determined the effects of grain size and nutritional conditions on the penetration rate and metabolic activity of Escherichia coli strains in anaerobic, nutrient-saturated chambers packed with different sizes of glass beads (diameters, 116 to 767 μm) under static conditions. The chambers had nearly equal porosities (38%) but different calculated pore sizes (range, 10 to 65 μm). Motile strains always penetrated faster than nonmotile strains, and nutrient conditions that resulted in faster growth rates (fermentative conditions versus nitrate-respiring conditions) resulted in faster penetration rates for both motile and nonmotile strains for all of the bead sizes tested. The penetration rate of nonmotile strains increased linearly when bead size was increased, while the penetration rate of motile strains became independent of the bead size when beads having diameters of 398 μm or greater were used. The rate of H2 production and the final amount of H2 produced decreased when bead size was decreased. However, the final protein concentrations were similar in chambers packed with 116-, 192-, and 281-μm beads and were only slightly higher in chambers packed with 398- and 767-μm beads. Our data indicated that conditions that favored faster growth rates also resulted in faster penetration times and that the lower penetration rates observed in chambers packed with small beads were due to restriction of bacterial activity in the small pores. The large increases in the final amount of hydrogen produced without corresponding increases in the final amount of protein made indicated that metabolism became uncoupled from cell mass biosynthesis as bead size increased, suggesting that pore size influenced the efficiency of substrate utilization. PMID:16349250

  12. Active sensing: An innovative tool for evaluating grain yield and nitrogen use efficiency of multiple wheat genotypes

    NASA Astrophysics Data System (ADS)

    Naser, Mohammed Abdulridha

    Precision agricultural practices have significantly contributed to the improvement of crop productivity and profitability. Remote sensing based indices, such as Normalized Difference Vegetative Index (NDVI) have been used to obtain crop information. It is used to monitor crop development and to provide rapid and nondestructive estimates of plant biomass, nitrogen (N) content and grain yield. Remote sensing tools are helping improve nitrogen use efficiency (NUE) through nitrogen management and could also be useful for high NUE genotype selection. The objectives of this study were: (i) to determine if active sensor based NDVI readings can differentiate wheat genotypes, (ii) to determine if NDVI readings can be used to classify wheat genotypes into grain yield productivity classes, (iii) to identify and quantify the main sources of variation in NUE across wheat genotypes, and (iv) to determine if normalized difference vegetation index (NDVI) could characterize variability in NUE across wheat genotypes. This study was conducted in north eastern Colorado for two years, 2010 and 2011. The NDVI readings were taken weekly during the winter wheat growing season from March to late June, in 2010 and 2011 and NUE were calculated as partial factor productivity and as partial nitrogen balance at the end of the season. For objectives i and ii, the correlation between NDVI and grain yield was determined using Pearson's product-moment correlation coefficient (r) and linear regression analysis was used to explain the relationship between NDVI and grain yield. The K-means clustering algorithm was used to classify mean NDVI and mean grain yield into three classes. For objectives iii and iv, the parameters related to NUE were also calculated to measure their relative importance in genotypic variation of NUE and power regression analysis between NDVI and NUE was used to characterize the relationship between NDVI and NUE. The results indicate more consistent association between grain

  13. Application of a new xylanase activity from Bacillus amyloliquefaciens XR44A in brewer's spent grain saccharification

    PubMed Central

    Amore, Antonella; Parameswaran, Binod; Kumar, Ramesh; Birolo, Leila; Vinciguerra, Roberto; Marcolongo, Loredana; Ionata, Elena; La Cara, Francesco; Pandey, Ashok; Faraco, Vincenza

    2015-01-01

    Background Cellulases and xylanases are the key enzymes involved in the conversion of lignocelluloses into fermentable sugars. Western Ghat region (India) has been recognized as an active hot spot for the isolation of new microorganisms. The aim of this work was to isolate new microorganisms producing cellulases and xylanases to be applied in brewer's spent grain saccharification. Results 93 microorganisms were isolated from Western Ghat and screened for the production of cellulase and xylanase activities. Fourteen cellulolytic and seven xylanolytic microorganisms were further screened in liquid culture. Particular attention was focused on the new isolate Bacillus amyloliquefaciens XR44A, producing xylanase activity up to 10.5 U mL−1. A novel endo-1,4-beta xylanase was identified combining zymography and proteomics and recognized as the main enzyme responsible for B. amyloliquefaciens XR44A xylanase activity. The new xylanase activity was partially characterized and its application in saccharification of brewer's spent grain, pretreated by aqueous ammonia soaking, was investigated. Conclusion The culture supernatant of B. amyloliquefaciens XR44A with xylanase activity allowed a recovery of around 43% xylose during brewer's spent grain saccharification, similar to the value obtained with a commercial xylanase from Trichoderma viride, and a maximum arabinose yield of 92%, around 2-fold higher than that achieved with the commercial xylanase. © 2014 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25866429

  14. Aromatic plants essential oils activity on Fusarium verticillioides Fumonisin B(1) production in corn grain.

    PubMed

    López, A G; Theumer, M G; Zygadlo, J A; Rubinstein, H R

    2004-10-01

    The minimum inhibitory concentration (MIC) of Origanum vulgare, Aloysia triphylla, Aloysia polystachya and Mentha piperita essential oils (EOs) against Fusarium verticillioides M 7075 (F. moniliforme, Sheldon) were assessed, using the semisolid agar antifungal susceptibility (SAAS) technique. O. vulgare, A. triphylla, A. polystachya and M. piperita EOs were evaluated at final concentrations of 10, 20, 40, 50, 100, 200, 250, 500, 1000 and 1500 epsilonl per litre (epsilonl/l) of culture medium. A. triphylla and O. vulgare EOs showed the highest inhibitory effects on F. verticillioides mycelial development. This inhibition was observed at 250 and 500 epsilonl/l for EOs coming from Aloysia triphylla and O. vulgare, respectively. Thus, the effects of EOs on FB(1) production were evaluated using corn grain (Zea mays) as substrate. The EOs were inserted on the 5th, 10th, 15th and 20th day of maize postinoculation with a conidia suspension of F. verticillioides. O. vulgare and A. triphylla were applied to give final concentrations of 30 ppm and 45 ppm, respectively. Different effects were observed in the toxicogenicity at the 20th day treatment. The O. vulgare EO decreased the production level of FB(1) (P < 0.01) while A. triphyla EO increased it (P < 0.001) with respect to those obtained in the inoculated maize, not EOs treated. Results obtained in the present work indicate that fumonisin production could be inhibited or stimulated by some constituents of EOs coming from aromatic plants. Further studies should be performed to identify the components of EOs with modulatory activity on the growth and fumonisins production of Fusarium verticillioides.

  15. Aromatic plants essential oils activity on Fusarium verticillioides Fumonisin B(1) production in corn grain.

    PubMed

    López, A G; Theumer, M G; Zygadlo, J A; Rubinstein, H R

    2004-10-01

    The minimum inhibitory concentration (MIC) of Origanum vulgare, Aloysia triphylla, Aloysia polystachya and Mentha piperita essential oils (EOs) against Fusarium verticillioides M 7075 (F. moniliforme, Sheldon) were assessed, using the semisolid agar antifungal susceptibility (SAAS) technique. O. vulgare, A. triphylla, A. polystachya and M. piperita EOs were evaluated at final concentrations of 10, 20, 40, 50, 100, 200, 250, 500, 1000 and 1500 epsilonl per litre (epsilonl/l) of culture medium. A. triphylla and O. vulgare EOs showed the highest inhibitory effects on F. verticillioides mycelial development. This inhibition was observed at 250 and 500 epsilonl/l for EOs coming from Aloysia triphylla and O. vulgare, respectively. Thus, the effects of EOs on FB(1) production were evaluated using corn grain (Zea mays) as substrate. The EOs were inserted on the 5th, 10th, 15th and 20th day of maize postinoculation with a conidia suspension of F. verticillioides. O. vulgare and A. triphylla were applied to give final concentrations of 30 ppm and 45 ppm, respectively. Different effects were observed in the toxicogenicity at the 20th day treatment. The O. vulgare EO decreased the production level of FB(1) (P < 0.01) while A. triphyla EO increased it (P < 0.001) with respect to those obtained in the inoculated maize, not EOs treated. Results obtained in the present work indicate that fumonisin production could be inhibited or stimulated by some constituents of EOs coming from aromatic plants. Further studies should be performed to identify the components of EOs with modulatory activity on the growth and fumonisins production of Fusarium verticillioides. PMID:15702272

  16. Effects of Storage Duration and Temperature on the Chemical Composition, Microorganism Density, and In vitro Rumen Fermentation of Wet Brewers Grains.

    PubMed

    Wang, B; Luo, Y; Myung, K H; Liu, J X

    2014-06-01

    This study aimed to investigate the effects of storage duration and temperature on the characteristics of wet brewers grains (WBG) as feeds for ruminant animals. Four storage temperatures (5°C, 15°C, 25°C, and 35°C) and four durations (0, 1, 2, and 3 d) were arranged in a 4×4 factorial design. Surface spoilage, chemical composition and microorganism density were analyzed. An in vitro gas test was also conducted to determine the pH, ammonia-nitrogen and volatile fatty acid (VFA) concentrations after 24 h incubation. Surface spoilage was apparent at higher temperatures such as 25°C and 35°C. Nutrients contents decreased concomitantly with prolonged storage times (p<0.01) and increasing temperatures (p<0.01). The amount of yeast and mold increased (p<0.05) with increasing storage times and temperatures. As storage temperature increased, gas production, in vitro disappearance of organic matter, pH, ammonia nitrogen and total VFA from the WBG in the rumen decreased (p<0.01). Our results indicate that lower storage temperature promotes longer beneficial use period. However, when storage temperature exceeds 35°C, WBG should be used within a day to prevent impairment of rumen fermentation in the subtropics such as Southeast China, where the temperature is typically above 35°C during summer.

  17. Effects of Storage Duration and Temperature on the Chemical Composition, Microorganism Density, and In vitro Rumen Fermentation of Wet Brewers Grains

    PubMed Central

    Wang, B.; Luo, Y.; Myung, K. H.; Liu, J. X.

    2014-01-01

    This study aimed to investigate the effects of storage duration and temperature on the characteristics of wet brewers grains (WBG) as feeds for ruminant animals. Four storage temperatures (5°C, 15°C, 25°C, and 35°C) and four durations (0, 1, 2, and 3 d) were arranged in a 4×4 factorial design. Surface spoilage, chemical composition and microorganism density were analyzed. An in vitro gas test was also conducted to determine the pH, ammonia-nitrogen and volatile fatty acid (VFA) concentrations after 24 h incubation. Surface spoilage was apparent at higher temperatures such as 25°C and 35°C. Nutrients contents decreased concomitantly with prolonged storage times (p<0.01) and increasing temperatures (p<0.01). The amount of yeast and mold increased (p<0.05) with increasing storage times and temperatures. As storage temperature increased, gas production, in vitro disappearance of organic matter, pH, ammonia nitrogen and total VFA from the WBG in the rumen decreased (p<0.01). Our results indicate that lower storage temperature promotes longer beneficial use period. However, when storage temperature exceeds 35°C, WBG should be used within a day to prevent impairment of rumen fermentation in the subtropics such as Southeast China, where the temperature is typically above 35°C during summer. PMID:25050021

  18. A wheat 1-FEH w3 variant underlies enzyme activity for stem WSC remobilization to grain under drought.

    PubMed

    Zhang, Jingjuan; Xu, Yunji; Chen, Wei; Dell, Bernard; Vergauwen, Rudy; Biddulph, Ben; Khan, Nusrat; Luo, Hao; Appels, Rudi; Van den Ende, Wim

    2015-01-01

    In wheat stems, the levels of fructan-dominated water-soluble carbohydrates (WSC) do not always correlate well with grain yield. Field drought experiments were carried out to further explain this lack of correlation. Wheat (Triticum aestivum) varieties, Westonia, Kauz and c. 20 genetically diverse double haploid (DH) lines derived from them were investigated. Substantial genotypic differences in fructan remobilization were found and the 1-FEH w3 gene was shown to be the major contributor in the stem fructan remobilization process based on enzyme activity and gene expression results. A single nucleotide polymorphism (SNP) was detected in an auxin response element in the 1-FEH w3 promoter region, therefore we speculated that the mutated Westonia allele might affect gene expression and enzyme activity levels. A cleaved amplified polymorphic (CAP) marker was generated from the SNP. The harvested results showed that the mutated Westonia 1-FEH w3 allele was associated with a higher thousand grain weight (TGW) under drought conditions in 2011 and 2012. These results indicated that higher gene expression of 1-FEH w3 and 1-FEH w3 mediated enzyme activities that favoured stem WSC remobilization to the grains. The CAP marker residing in the 1-FEH w3 promoter region may facilitate wheat breeding by selecting lines with high stem fructan remobilization capacity under terminal drought.

  19. Characterization of grain boundaries in silicon

    NASA Technical Reports Server (NTRS)

    Cheng, L. J.; Shyu, C. M.; Stika, K. M.; Daud, T.; Crotty, G. T.

    1983-01-01

    Zero-bias conductance and capacitance measurements at various temperatures were used to study trapped charges and potential barrier height at the boundaries. Deep-level transient spectroscopy (DLTS) was applied to measure the density of states at the boundary. A study of photoconductivity of grain boundaries in p-type silicon demonstrated the applicability of the technique in the measurement of minority carrier recombination velocity at the grain boundary. Enhanced diffusion of phosphorus at grain boundaries in three cast polycrystalline photovoltaic materials was studied. Enhancements for the three were the same, indicating that the properties of boundaries are similar, although grown by different techniques. Grain boundaries capable of enhancing the diffusion were found always to have strong recombination activities; the phenomena could be related to dangling bonds at the boundaries. Evidence that incoherent second-order twins of (111)/(115) type are diffusion-active is presented.

  20. AHA! A Cool Salt Water/Density Activity--The Joy of Designing a Simple Experiment.

    ERIC Educational Resources Information Center

    Carlson, Gaylen R.

    1998-01-01

    Describes two science activities concerning water density and shares an idea for combining these activities into a third, completely new activity. Demonstrates the joy of rekindling the spirit of scientific thinking in a typical classroom. (PVD)

  1. Coarse-grained modeling study of nonpeptide RGD ligand density and PEG molecular weight on the conformation of poly(γ-glutamyl-glutamate) paclitaxel conjugates.

    PubMed

    Peng, Lili X; Das, Sanjib K; Yu, Lei; Howell, Stephen B; Gough, David A

    2011-11-01

    Molecular shape, flexibility, and surface hydrophilicity are thought to influence the ability of nanoparticles to cross biological barriers during drug delivery. In this study, coarse-grained (CG) molecular dynamics (MD) simulations were used to study these properties of a polymer-drug construct in potential clinical development: poly(γ-glutamyl-glutamate)-paclitaxel-poly(ethylene glycol) nonpeptide RGD (PGG-PTX-PEG-npRGD), a linear glutamyl-glutamate polymer with paclitaxel and poly(ethylene glycol)-nonpeptide RGD side groups. It was hypothesized that the PEG molecular weight (MW) (500 Da; 1,000 Da; and 2,000 Da) and nonpeptide RGD ligand density (4, 8, 12, and 16 per molecule), respectively, may have advantageous effects on the shape, flexibility, and surface hydrophilicity of PGG-PTX-PEG-npRGD. Circular dichroism spectroscopy was used to suggest initial structures for the all-atom (AA) models of PGG-PTX-PEG-npRGD, which were further converted to CG models using a commercially available mapping algorithm. Due to its semi-flexibility, PGG-PTX-PEG-npRGD is not limited to one specific conformation. Thus, CG MD simulations were run until statistical equilibrium, at which PGG-PTX-PEG-npRGD is represented as an ensemble of statistically similar conformations. The size of a PGG-PTX-PEG-npRGD molecule is not affected by the PEG MW or the nonpeptide RGD density, but higher PEG MW results in increased surface density of a PGG-PTX-PEG-npRGD molecule. Most PGG-PTX-PEG-npRGD shapes are globular, although filamentous shapes were also observed in the PEG500 and PEG1000 molecules. PEG500 and PEG1000 molecules are more flexible than PEG2000 systems. A higher presence of npRGD ligands results in decrease surface hydrophilicity of PGG-PTX-PEG-npRGD. These results indicate that the PGG-PTX-PEG1000-npRGD(4) and PGG-PTX-PEG1000-npRGD(8) molecules are the most efficacious candidates and are further recommended for experimental preclinical studies.

  2. Density increase due to active feedback in mirror machine

    NASA Astrophysics Data System (ADS)

    Seemann, Omri; Be'Ery, Ilan

    2014-10-01

    Mirror machines are one of the schemes for future fusion systems. Its main drawbacks are the flute instability and being open ended which results in plasma losses. A feedback system is used to stabilize the flute instability in a table top mirror machine with a continuous plasma source and RF heating. Under certain source density and temperature conditions, although the plasma was stabilized, plasma density increase was not measured. After decreasing the source density and increasing the temperature, Plasma density increase was achieved. It is theorized that these results are due to transition of the plasma main loss mechanism from collision dominated to instability dominated. In the former, the main density loss is through diffusion and In the latter, it is through flute instability which drives the plasma to the edge of the vacuum chamber. Future research directions are discussed for a planned machine which should achieve higher temperatures and better diagnostic capabilities. The research will focus on magnetic actuators and passive RF stabilization.

  3. Optimization of processing conditions to improve antioxidant activities of apple juice and whey based novel beverage fermented by kefir grains.

    PubMed

    Sabokbar, Nayereh; Khodaiyan, Faramarz; Moosavi-Nasab, Marzieh

    2015-06-01

    A central composite design (CCD) was used to evaluate the effects of fermentation temperature (20-30 ºC) and kefir grains amount (2-8%w/v) on total phenolic content and antioxidant activities of apple juice and whey based novel beverage fermented by kefir grains. The response surface methodology (RSM) showed that the significant second-order polynomial regression equation with high R(2) (>0.86) was successfully fitted for all response as function of independent variable. The overall optimum region was found to be at the combined level of 7.56%w/v kefir grains and temperature of 24.82 ºC with the highest value for total phenolic content (TPC) and antioxidant activities. At this optimum point TPC, 1, 1-Diphenyl-2-picrylhydrazyl radical scavenging, metal chelating effect, reducing power, inhibition of linoleic acid autoxidation and inhibition of ascorbate autoxidation were 165.02 mgGA/l, 0.38 ml/1 ml, 0.757 (absorbance at 700 nm), 46.12 %, 65.33 % and 21 %, respectively. No significant difference (p < 0.05) was found between actual values and predicated values.

  4. Observational support for dust grain emission by electrostatic forces

    NASA Astrophysics Data System (ADS)

    Silen, Johan; Hilchenbach, Martin; Hornung, Klaus; Merouane, Sihane; Schulz, Rita

    2015-04-01

    Dust collected close to the comet 67P by the COSIMA instrument, indicates that fluffy grains up to sizes of several 100 um are lifted off the comet surface and transported to the instrument substrate several tens of kilometers away. The temperature of the surface and the detected gas densities are too low to properly explain lifting grains from the cometary surface. We investigate grain dynamics using electrostatic forces. Comet surface lighting conditions create small scale multi pole electric fields by photons. These fields create forces on both charged and neutral dust grains and may serve as "active regions". The forces acting on the grain, scale as D3 with grain size and therefore large grains are proportionally simpler to elevate, provided the mass is not increasing at the same rate. The fluffy structure of the grains seem to fulfill this requirement. The limiting factor of this mechanism is set by the tensile strength of the grains. If the electrostatic force created exceeds the tensile strength, the grain will disintegrate through Coulomb explosion. The mechanism would favor lifting large fluffy grains off the surface because they have a capability of most easily creating mobile charges which interact in a favorable manner with the multi pole fields. Because of the conglomerate nature of the grains, a splitting of a grain may trigger a Coulomb explosion setting free the bulk dust distribution of small grains detected. The measured elongated impacts also suggest that disintegration is taking place close to the spacecraft. This would also be supported by the proposed model as the space craft charging represents a small scale field anomaly where grain splitting could become enhanced. The observed grains seem to fulfill all requirements of this tentative model.

  5. Catalytic activities of platinum nanotubes: a density functional study

    NASA Astrophysics Data System (ADS)

    Mukherjee, Prajna; Gupta, Bikash C.; Jena, Puru

    2015-10-01

    In this work we investigate the catalytic properties of platinum nanotubes using density functional theory based calculations. In particular, we study the dissociation of hydrogen and oxygen molecules as well as oxidation of CO molecules. The results indicate that platinum nanotubes have good catalytic properties and can be effectively used in converting CO molecule to CO2.

  6. Sintering process and critical current density of low activation Mg11B2 superconductors from low temperature to high temperature

    NASA Astrophysics Data System (ADS)

    Cheng, Fang; Liu, Yongchang; Ma, Zongqing; Shahriar Al Hossain, Md; Somer, M.

    2016-08-01

    As the "low activation" superconductor, Mg11B2 has a potential application in superconducting coils for fusion reactor. In present work, the sintering process and critical current density of low activation Mg11B2 superconductors were systemically studied from low temperature to high temperature. It was found that the Jc and Hirr values of Mg11B2 bulks in present work are both obviously higher than that of those samples prepared in previous studies. Furthermore, the low-temperature sintered samples exhibit better Jc performance at high fields than the high-temperature sintered samples, due to strong grain boundaries pinning. On the other hand, the high-temperature sintered samples have higher Jc at low fields compared to low-temperature sintered samples, mainly owing to their better crystallinity and grain connectivity. The highest Jc value (2.20 ×105 A cm-2 at 20 K, self-field) is obtained in the Mg11B2 sample sintered at 850 °C for 45 min.

  7. Implementing an Inexpensive and Accurate Introductory Gas Density Activity with High School Students

    ERIC Educational Resources Information Center

    Cunningham, W. Patrick; Joseph, Christopher; Morey, Samantha; Santos Romo, Ana; Shope, Cullen; Strang, Jonathan; Yang, Kevin

    2015-01-01

    A simplified activity examined gas density while employing cost-efficient syringes in place of traditional glass bulbs. The exercise measured the density of methane, with very good accuracy and precision, in both first-year high school and AP chemistry settings. The participating students were tasked with finding the density of a gas. The…

  8. No Evidence for Activity Adjustment in Response to Increased Density in Daphnia magna.

    PubMed

    Sereni, Laura; Einum, Sigurd

    2015-01-01

    Increased population density may lead to a decrease in energy available for growth and reproduction via effects on the activity level of individuals. Whilst this may be of particular importance for organisms that compete for defendable resources and/or have a high frequency of social interactions, it is less obvious how individual activity should covary with population density when food resources are not defendable or direct interactions among individuals are negligible. Based on observations that there is a general negative relationship between population density and metabolism it has been suggested that organisms actively reduce activity under increased density to accommodate an expected decrease in food availability. However, in the absence of direct activity measurements the validity of this hypothesis is unclear. Here we test for such anticipatory adjustments of activity levels in the planktonic cladoceran Daphnia magna Straus, a filter feeder whose food resources are not defendable, meaning that density responses can be evaluated in the absence of direct interactions. We tested for changes in activity in response to two separate density cues, one being the direct physical and visual stimuli resulting from being in the vicinity of conspecifics ('direct density experiment'), and the other being the detection of olfactory cues in their environment ('olfactory cue experiment'). Ten genetically distinct clones were used to evaluate the potential for genetic variation in these responses. Our measures of activity were highly repeatable, and there was significant variation in activity among clones. Furthermore, this clonal variation was consistent in the 'direct density' and 'olfactory cue' experiments. The estimated evolvability of the trait (1.3-3.2%) was within the range typically observed in behavioural traits. However, there was no indication that the activity level of individuals respond to population density, either directly to actual density or to olfactory

  9. A combined coarse-grained and all-atom simulation of TRPV1 channel gating and heat activation

    PubMed Central

    Qin, Feng

    2015-01-01

    The transient receptor potential (TRP) channels act as key sensors of various chemical and physical stimuli in eukaryotic cells. Despite years of study, the molecular mechanisms of TRP channel activation remain unclear. To elucidate the structural, dynamic, and energetic basis of gating in TRPV1 (a founding member of the TRPV subfamily), we performed coarse-grained modeling and all-atom molecular dynamics (MD) simulation based on the recently solved high resolution structures of the open and closed form of TRPV1. Our coarse-grained normal mode analysis captures two key modes of collective motions involved in the TRPV1 gating transition, featuring a quaternary twist motion of the transmembrane domains (TMDs) relative to the intracellular domains (ICDs). Our transition pathway modeling predicts a sequence of structural movements that propagate from the ICDs to the TMDs via key interface domains (including the membrane proximal domain and the C-terminal domain), leading to sequential opening of the selectivity filter followed by the lower gate in the channel pore (confirmed by modeling conformational changes induced by the activation of ICDs). The above findings of coarse-grained modeling are robust to perturbation by lipids. Finally, our MD simulation of the ICD identifies key residues that contribute differently to the nonpolar energy of the open and closed state, and these residues are predicted to control the temperature sensitivity of TRPV1 gating. These computational predictions offer new insights to the mechanism for heat activation of TRPV1 gating, and will guide our future electrophysiology and mutagenesis studies. PMID:25918362

  10. High Fc Density Particles Result in Binary Complement Activation but Tunable Macrophage Phagocytosis

    NASA Astrophysics Data System (ADS)

    Sulchek, Todd; Pacheco, Patricia; White, David

    2014-03-01

    Macrophage phagocytosis and complement system activation represent two key components of the immune system and both can be activated through the presentation of multiple Fc domains of IgG antibodies. We have created functionalized micro- and nanoparticles with various densities of Fc domains to understand the modulation of the immune system for eventual use as a novel immunomodulation platform. Phagocytosis assays were carried out by adding functionalized particles to macrophage cells and quantitatively determined using fluorescent microscopy and flow cytometry. Complement system activation by the functionalized particles in human serum was quantified with an enzyme immunoassay. Our phagocytosis assay revealed a strong dependence on particle size and Fc density. For small particles, as the Fc density increased, the number of particles phagocytosed also increased. Large particles were phagocytosed at significantly lower levels and showed no dependency on Fc density. Complement was successfully activated at levels comparable to positive controls for small particles at high Fc densities. However at low Fc densities, there is a significant decrease in complement activation. This result suggests a binary response for complement system activation with a threshold density for successful activation. Therefore, varying the Fc density on micro/nanoparticles resulted in a tunable response in macrophage phagocytosis while a more binary response for complement activation.

  11. Changes in the activities of starch metabolism enzymes in rice grains in response to elevated CO2 concentration.

    PubMed

    Xie, Li-Yong; Lin, Er-Da; Zhao, Hong-Liang; Feng, Yong-Xiang

    2016-05-01

    The global atmospheric CO(2) concentration is currently (2012) 393.1 μmol mol(-1), an increase of approximately 42 % over pre-industrial levels. In order to understand the responses of metabolic enzymes to elevated CO(2) concentrations, an experiment was conducted using the Free Air CO(2) Enrichment (FACE )system. Two conventional japonica rice varieties (Oryza sativa L. ssp. japonica) grown in North China, Songjing 9 and Daohuaxiang 2, were used in this study. The activities of ADPG pyrophosphorylase, soluble and granule-bound starch synthases, and soluble and granule-bound starch branching enzymes were measured in rice grains, and the effects of elevated CO(2) on the amylose and protein contents of the grains were analyzed. The results showed that elevated CO(2) levels significantly increased the activity of ADPG pyrophosphorylase at day 8, 24, and 40 after flower, with maximum increases of 56.67 % for Songjing 9 and 21.31 % for Daohuaxiang 2. Similarly, the activities of starch synthesis enzymes increased significantly from the day 24 after flower to the day 40 after flower, with maximum increases of 36.81 % for Songjing 9 and 66.67 % for Daohuaxiang 2 in soluble starch synthase (SSS), and 25.00 % for Songjing 9 and 36.44 % for Daohuaxiang 2 in granule-bound starch synthase (GBSS), respectively. The elevated CO(2) concentration significantly increased the activity of soluble starch branching enzyme (SSBE) at day 16, 32, and 40 after flower, and also significantly increased the activity of granule-bound starch branching enzyme (GBSBE) at day 8, 32, and 40 after flower. The elevated CO(2) concentration increased the peak values of enzyme activity, and the timing of the activity peaks for SSS and GBSBE were earlier in Songjing 9 than in Daohuaxiang 2. There were obvious differences in developmental stages between the two varieties of rice, which indicated that the elevated CO(2) concentration increased enzyme activity expression and starch synthesis, affecting the

  12. Changes in the activities of starch metabolism enzymes in rice grains in response to elevated CO2 concentration

    NASA Astrophysics Data System (ADS)

    Xie, Li-Yong; Lin, Er-Da; Zhao, Hong-Liang; Feng, Yong-Xiang

    2016-05-01

    The global atmospheric CO2 concentration is currently (2012) 393.1 μmol mol-1, an increase of approximately 42 % over pre-industrial levels. In order to understand the responses of metabolic enzymes to elevated CO2 concentrations, an experiment was conducted using the Free Air CO2 Enrichment (FACE )system. Two conventional japonica rice varieties ( Oryza sativa L. ssp. japonica) grown in North China, Songjing 9 and Daohuaxiang 2, were used in this study. The activities of ADPG pyrophosphorylase, soluble and granule-bound starch synthases, and soluble and granule-bound starch branching enzymes were measured in rice grains, and the effects of elevated CO2 on the amylose and protein contents of the grains were analyzed. The results showed that elevated CO2 levels significantly increased the activity of ADPG pyrophosphorylase at day 8, 24, and 40 after flower, with maximum increases of 56.67 % for Songjing 9 and 21.31 % for Daohuaxiang 2. Similarly, the activities of starch synthesis enzymes increased significantly from the day 24 after flower to the day 40 after flower, with maximum increases of 36.81 % for Songjing 9 and 66.67 % for Daohuaxiang 2 in soluble starch synthase (SSS), and 25.00 % for Songjing 9 and 36.44 % for Daohuaxiang 2 in granule-bound starch synthase (GBSS), respectively. The elevated CO2 concentration significantly increased the activity of soluble starch branching enzyme (SSBE) at day 16, 32, and 40 after flower, and also significantly increased the activity of granule-bound starch branching enzyme (GBSBE) at day 8, 32, and 40 after flower. The elevated CO2 concentration increased the peak values of enzyme activity, and the timing of the activity peaks for SSS and GBSBE were earlier in Songjing 9 than in Daohuaxiang 2. There were obvious differences in developmental stages between the two varieties of rice, which indicated that the elevated CO2 concentration increased enzyme activity expression and starch synthesis, affecting the final contents

  13. Chemotaxis of artificial microswimmers in active density waves.

    PubMed

    Geiseler, Alexander; Hänggi, Peter; Marchesoni, Fabio; Mulhern, Colm; Savel'ev, Sergey

    2016-07-01

    Living microorganisms are capable of a tactic response to external stimuli by swimming toward or away from the stimulus source; they do so by adapting their tactic signal transduction pathways to the environment. Their self-motility thus allows them to swim against a traveling tactic wave, whereas a simple fore-rear asymmetry argument would suggest the opposite. Their biomimetic counterpart, the artificial microswimmers, also propel themselves by harvesting kinetic energy from an active medium, but, in contrast, lack the adaptive capacity. Here we investigate the transport of artificial swimmers subject to traveling active waves and show, by means of analytical and numerical methods, that self-propelled particles can actually diffuse in either direction with respect to the wave, depending on its speed and waveform. Moreover, chiral swimmers, which move along spiraling trajectories, may diffuse preferably in a direction perpendicular to the active wave. Such a variety of tactic responses is explained by the modulation of the swimmer's diffusion inside traveling active pulses. PMID:27575185

  14. Chemotaxis of artificial microswimmers in active density waves

    NASA Astrophysics Data System (ADS)

    Geiseler, Alexander; Hänggi, Peter; Marchesoni, Fabio; Mulhern, Colm; Savel'ev, Sergey

    2016-07-01

    Living microorganisms are capable of a tactic response to external stimuli by swimming toward or away from the stimulus source; they do so by adapting their tactic signal transduction pathways to the environment. Their self-motility thus allows them to swim against a traveling tactic wave, whereas a simple fore-rear asymmetry argument would suggest the opposite. Their biomimetic counterpart, the artificial microswimmers, also propel themselves by harvesting kinetic energy from an active medium, but, in contrast, lack the adaptive capacity. Here we investigate the transport of artificial swimmers subject to traveling active waves and show, by means of analytical and numerical methods, that self-propelled particles can actually diffuse in either direction with respect to the wave, depending on its speed and waveform. Moreover, chiral swimmers, which move along spiraling trajectories, may diffuse preferably in a direction perpendicular to the active wave. Such a variety of tactic responses is explained by the modulation of the swimmer's diffusion inside traveling active pulses.

  15. Differential regulation of grain sucrose accumulation and metabolism in Coffea arabica (Arabica) and Coffea canephora (Robusta) revealed through gene expression and enzyme activity analysis.

    PubMed

    Privat, Isabelle; Foucrier, Séverine; Prins, Anneke; Epalle, Thibaut; Eychenne, Magali; Kandalaft, Laurianne; Caillet, Victoria; Lin, Chenwei; Tanksley, Steve; Foyer, Christine; McCarthy, James

    2008-01-01

    * Coffea arabica (Arabica) and Coffea canephora (Robusta) are the two main cultivated species used for coffee bean production. Arabica genotypes generally produce a higher coffee quality than Robusta genotypes. Understanding the genetic basis for sucrose accumulation during coffee grain maturation is an important goal because sucrose is an important coffee flavor precursor. * Nine new Coffea genes encoding sucrose metabolism enzymes have been identified: sucrose phosphate synthase (CcSPS1, CcSPS2), sucrose phosphate phosphatase (CcSP1), cytoplasmic (CaInv3) and cell wall (CcInv4) invertases and four invertase inhibitors (CcInvI1, 2, 3, 4). * Activities and mRNA abundance of the sucrose metabolism enzymes were compared at different developmental stages in Arabica and Robusta grains, characterized by different sucrose contents in mature grain. * It is concluded that Robusta accumulates less sucrose than Arabica for two reasons: Robusta has higher sucrose synthase and acid invertase activities early in grain development - the expression of CcSS1 and CcInv2 appears to be crucial at this stage and Robusta has a lower SPS activity and low CcSPS1 expression at the final stages of grain development and hence has less capacity for sucrose re-synthesis. Regulation of vacuolar invertase CcInv2 activity by invertase inhibitors CcInvI2 and/or CcInvI3 during Arabica grain development is considered. PMID:18384509

  16. Control of grain growth using intergranular silicate phases in cubic yttria stabilized zirconia

    SciTech Connect

    Sharif, A.A.; Imamura, P.H.; Mecartney, M.L.; Mitchell, T.E.

    1998-07-01

    Grain growth kinetics for 8 mol% yttria stabilized cubic zirconia (8Y-CSZ) were investigated. Optimal process parameters required to achieve a small grain size and full density for cubic 8Y-CSZ included a rapid heating rate (100 C/min) and hot isostatic pressing. Grain growth rates could also be controlled by the deliberate addition of 1 wt% of intergranular phases of borosilicate, barium silicate, and lithium aluminum silicate glasses. Lithium aluminum silicate, the intergranular phase with the highest solubility for yttria and zirconia, enhanced grain growth compared to control samples without grain boundary phases. The borosilicate intergranular phase, with the lowest solubility for yttria and zirconia, was the most effective in suppressing grain growth. Activation energies for grain growth were in the range of 400 kJ/mol, and the grain growth exponent ranged from 2 for lithium aluminum silicate containing samples, to 3 for pure samples, to 4 for barium silicate and borosilicate containing samples.

  17. Additivity, density fluctuations, and nonequilibrium thermodynamics for active Brownian particles

    NASA Astrophysics Data System (ADS)

    Chakraborti, Subhadip; Mishra, Shradha; Pradhan, Punyabrata

    2016-05-01

    Using an additivity property, we study particle-number fluctuations in a system of interacting self-propelled particles, called active Brownian particles (ABPs), which consists of repulsive disks with random self-propulsion velocities. From a fluctuation-response relation, a direct consequence of additivity, we formulate a thermodynamic theory which captures the previously observed features of nonequilibrium phase transition in the ABPs from a homogeneous fluid phase to an inhomogeneous phase of coexisting gas and liquid. We substantiate the predictions of additivity by analytically calculating the subsystem particle-number distributions in the homogeneous fluid phase away from criticality where analytically obtained distributions are compatible with simulations in the ABPs.

  18. On the relationship between grain-boundary migration and grain-boundary diffusion by molecular-dynamics simulation

    SciTech Connect

    Schoenfelder, B. |; Keblinski, P.; Wolf, D.; Phillpot, S.R.

    1998-07-01

    A molecular-dynamics method for the simulation of the intrinsic migration behavior of individual, flat grain boundaries is presented. A constant driving force for grain-boundary migration is generated by imposing an anisotropic elastic strain on a bicrystal such that the elastic-energy densities in its two halves are different. For the model case of the large-planar-unit-cell, high-angle (001) twist boundary in Cu the authors demonstrate that the drift velocity is proportional to the applied driving force, thus enabling determination of the boundary mobility. The activation energy for grain-boundary migration is found to be distinctly lower than that for grain-boundary self-diffusion. A decrease in the related activation energies with increasing temperature is shown to arise from a crossover in the underlying mechanisms, from solid-like at low temperatures to liquid-like at high-temperatures that is accompanied by an underlying grain-boundary structural transition.

  19. Fibrinogen patterns and activity on substrates with tailored hydroxy density.

    PubMed

    Rodríguez Hernández, José Carlos; Rico, Patricia; Moratal, David; Monleón Pradas, Manuel; Salmerón-Sánchez, Manuel

    2009-08-11

    The influence of the surface fraction of OH groups on fibrinogen (FG) adsorption is investigated in copolymers of ethyl acrylate and hydroxy ethylacrylate. The amount of adsorbed FG, quantified by western-blotting combined with image analysis of the corresponding bands, decreases as the hydrophilicity of the substrate increases. The influence of substrate wettability on FG conformation and distribution is observed by atomic force microscopy (AFM). The most hydrophobic substrate promotes FG fibrillogenesis, which leads to a fibrin-like appearance in the absence of any thrombin. The degree of FG interconnection was quantified by calculating the fractal dimension of the adsorbed protein from image analysis of the AFM results. The biological activity of the adsorbed FG is correlated to cell adhesion on FG-coated substrates.

  20. Long-time atomistic evolution of grain boundary in nickel using the kinetic activation-relaxation technique

    NASA Astrophysics Data System (ADS)

    Mahmoud, Sami; Trochet, Mickaël; Restrepo, Oscar; Mousseau, Normand

    The microscopic mechanisms associated with the evolution of metallic materials are still a matter of debate as both experimental and numerical approaches fail to provide a detailed atomic picture of their time evolution. Here, we use the kinetic activation-relaxation technique (k-ART), an unbiased off-lattice kinetic Monte Carlo method with on-the-fly catalog building to overcome these limitations and follow the atomistic evolution of a 10.000-atom grain boundary Ni system over macroscopic time scales. We first characterize the kinetic properties of four different empirical potentials, the embedded atom method (EAM), the first and second modified embedded atom method (MEAM1NN and MEAM2NN respectively) and the Reax force field (ReaxFF) potentials. Comparing the energetics, the elastic effects and the diffusion mechanisms for systems with one to three vacancies and one to three self-interstitials in nickel simulated over second time scale, we conclude that ReaxFF and EAM potentials are closest to experimental values. We then proceed to study the long-time evolution of a grain boundary with the Reax forcefield and to offer a detailed description of its energy landscape, including the exact description of short and long-range effects on self-diffusion along the interface

  1. Temperature and population density effects on locomotor activity of Musca domestica (Diptera: Muscidae).

    PubMed

    Schou, T M; Faurby, S; Kjærsgaard, A; Pertoldi, C; Loeschcke, V; Hald, B; Bahrndorff, S

    2013-12-01

    The behavior of ectotherm organisms is affected by both abiotic and biotic factors. However, a limited number of studies have investigated the synergistic effects on behavioral traits. This study examined the effect of temperature and density on locomotor activity of Musca domestica (L.). Locomotor activity was measured for both sexes and at four densities (with mixed sexes) during a full light and dark (L:D) cycle at temperatures ranging from 10 to 40°C. Locomotor activity during daytime increased with temperature at all densities until reaching 30°C and then decreased. High-density treatments significantly reduced the locomotor activity per fly, except at 15°C. For both sexes, daytime activity also increased with temperature until reaching 30 and 35°C for males and females, respectively, and thereafter decreased. Furthermore, males showed a significantly higher and more predictable locomotor activity than females. During nighttime, locomotor activity was considerably lower for all treatments. Altogether the results of the current study show that there is a significant interaction of temperature and density on daytime locomotor activity of M. domestica and that houseflies are likely to show significant changes in locomotor activity with change in temperature.

  2. Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts

    PubMed Central

    Sahraie, Nastaran Ranjbar; Kramm, Ulrike I.; Steinberg, Julian; Zhang, Yuanjian; Thomas, Arne; Reier, Tobias; Paraknowitsch, Jens-Peter; Strasser, Peter

    2015-01-01

    Carbon materials doped with transition metal and nitrogen are highly active, non-precious metal catalysts for the electrochemical conversion of molecular oxygen in fuel cells, metal air batteries, and electrolytic processes. However, accurate measurement of their intrinsic turn-over frequency and active-site density based on metal centres in bulk and surface has remained difficult to date, which has hampered a more rational catalyst design. Here we report a successful quantification of bulk and surface-based active-site density and associated turn-over frequency values of mono- and bimetallic Fe/N-doped carbons using a combination of chemisorption, desorption and 57Fe Mössbauer spectroscopy techniques. Our general approach yields an experimental descriptor for the intrinsic activity and the active-site utilization, aiding in the catalyst development process and enabling a previously unachieved level of understanding of reactivity trends owing to a deconvolution of site density and intrinsic activity. PMID:26486465

  3. Coarse-grained simulations of an active filament propelled by a self-generated solute gradient

    NASA Astrophysics Data System (ADS)

    Sarkar, Debarati; Thakur, Snigdha

    2016-03-01

    A self-propelling semiflexible filament exhibits a variety of dynamical states depending on the flexibility and activity of the filament. Here we investigate the dynamics of such an active filament using a bead-spring model with the explicit hydrodynamic interactions. The activity in the filament is incorporated by inserting chemically active dimers at regular intervals along the chain. The chemical reactions at the catalytic bead of the dimer produces a self-generated concentration gradient and gives sufficient fuel to exhibit self-propulsion for the filament. Depending upon the rigidity and the configuration, the polymeric filament exhibits three distinct types of spontaneous motion, namely, rotational, snaking, and translational motion. The self-propulsion velocity of the filament for various rigidity and sizes has been calculated, and the factors affecting the propulsion are identified.

  4. Structure-reactivity relationships between fluorescent chromophores and antioxidant activity of grain and sweet sorghum seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyphenolic structures, such as tannins, are the putative cause of a variety of seed functions including bird/insect resistance and antioxidant activity. Structure-reactivity relationships are necessary to understand the influence of polyphenolic chromophore structures on the tannin content and fr...

  5. Density-Dependent Spacing Behaviour and Activity Budget in Pregnant, Domestic Goats (Capra hircus)

    PubMed Central

    Vas, Judit; Andersen, Inger Lise

    2015-01-01

    Very little is known about the spacing behaviour in social groups of domestic goats (Capra hircus) in the farm environment. In this experiment, we studied interindividual distances, movement patterns and activity budgets in pregnant goats housed at three different densities. Norwegian dairy goats were kept in stable social groups of six animals throughout pregnancy at 1, 2 or 3 m2 per individual and their spacing behaviours (i.e. distance travelled, nearest and furthest neighbour distance) and activity budgets (e.g. resting, feeding, social activities) were monitored. Observations were made in the first, second and last thirds of pregnancy in the mornings, at noon and in the afternoons of each of these phases (4.5 hours per observation period). The findings show that goats held at animal densities of 2 and 3 m2 moved longer distances when they had more space per animal and kept larger nearest and furthest neighbour distances when compared to the 1 m2 per animal density. Less feeding activity was observed at the high animal density compared to the medium and low density treatments. The phase of gestation also had an impact on almost all behavioural variables. Closer to parturition, animals moved further distances and the increase in nearest and furthest neighbour distance was more pronounced at the lower animal densities. During the last period of gestation, goats spent less time feeding and more on resting, social behaviours and engaging in other various activities. Our data suggest that more space per goat is needed for goats closer to parturition than in the early gestation phase. We concluded that in goats spacing behaviour is density-dependent and changes with stages of pregnancy and activities. Finally, the lower density allowed animals to express individual preferences regarding spacing behaviour which is important in ensuring good welfare in a farming situation. PMID:26657240

  6. Density-Dependent Spacing Behaviour and Activity Budget in Pregnant, Domestic Goats (Capra hircus).

    PubMed

    Vas, Judit; Andersen, Inger Lise

    2015-01-01

    Very little is known about the spacing behaviour in social groups of domestic goats (Capra hircus) in the farm environment. In this experiment, we studied interindividual distances, movement patterns and activity budgets in pregnant goats housed at three different densities. Norwegian dairy goats were kept in stable social groups of six animals throughout pregnancy at 1, 2 or 3 m2 per individual and their spacing behaviours (i.e., distance travelled, nearest and furthest neighbour distance) and activity budgets (e.g., resting, feeding, social activities) were monitored. Observations were made in the first, second and last thirds of pregnancy in the mornings, at noon and in the afternoons of each of these phases (4.5 hours per observation period). The findings show that goats held at animal densities of 2 and 3 m2 moved longer distances when they had more space per animal and kept larger nearest and furthest neighbour distances when compared to the 1 m2 per animal density. Less feeding activity was observed at the high animal density compared to the medium and low density treatments. The phase of gestation also had an impact on almost all behavioural variables. Closer to parturition, animals moved further distances and the increase in nearest and furthest neighbour distance was more pronounced at the lower animal densities. During the last period of gestation, goats spent less time feeding and more on resting, social behaviours and engaging in other various activities. Our data suggest that more space per goat is needed for goats closer to parturition than in the early gestation phase. We concluded that in goats spacing behaviour is density-dependent and changes with stages of pregnancy and activities. Finally, the lower density allowed animals to express individual preferences regarding spacing behaviour which is important in ensuring good welfare in a farming situation.

  7. Detection and Classification of Finer-Grained Human Activities Based on Stepped-Frequency Continuous-Wave Through-Wall Radar.

    PubMed

    Qi, Fugui; Liang, Fulai; Lv, Hao; Li, Chuantao; Chen, Fuming; Wang, Jianqi

    2016-06-15

    The through-wall detection and classification of human activities are critical for anti-terrorism, security, and disaster rescue operations. An effective through-wall detection and classification technology is proposed for finer-grained human activities such as piaffe, picking up an object, waving, jumping, standing with random micro-shakes, and breathing while sitting. A stepped-frequency continuous wave (SFCW) bio-radar sensor is first used to conduct through-wall detection of finer-grained human activities; Then, a comprehensive range accumulation time-frequency transform (CRATFR) based on inverse weight coefficients is proposed, which aims to strengthen the micro-Doppler features of finer activity signals. Finally, in combination with the effective eigenvalues extracted from the CRATFR spectrum, an optimal self-adaption support vector machine (OS-SVM) based on prior human position information is introduced to classify different finer-grained activities. At a fixed position (3 m) behind a wall, the classification accuracies of six activities performed by eight individuals were 98.78% and 93.23%, respectively, for the two scenarios defined in this paper. In the position-changing experiment, an average classification accuracy of 86.67% was obtained for five finer-grained activities (excluding breathing) of eight individuals within 6 m behind the wall for the most practical scenario, a significant improvement over the 79% accuracy of the current method.

  8. Detection and Classification of Finer-Grained Human Activities Based on Stepped-Frequency Continuous-Wave Through-Wall Radar

    PubMed Central

    Qi, Fugui; Liang, Fulai; Lv, Hao; Li, Chuantao; Chen, Fuming; Wang, Jianqi

    2016-01-01

    The through-wall detection and classification of human activities are critical for anti-terrorism, security, and disaster rescue operations. An effective through-wall detection and classification technology is proposed for finer-grained human activities such as piaffe, picking up an object, waving, jumping, standing with random micro-shakes, and breathing while sitting. A stepped-frequency continuous wave (SFCW) bio-radar sensor is first used to conduct through-wall detection of finer-grained human activities; Then, a comprehensive range accumulation time-frequency transform (CRATFR) based on inverse weight coefficients is proposed, which aims to strengthen the micro-Doppler features of finer activity signals. Finally, in combination with the effective eigenvalues extracted from the CRATFR spectrum, an optimal self-adaption support vector machine (OS-SVM) based on prior human position information is introduced to classify different finer-grained activities. At a fixed position (3 m) behind a wall, the classification accuracies of six activities performed by eight individuals were 98.78% and 93.23%, respectively, for the two scenarios defined in this paper. In the position-changing experiment, an average classification accuracy of 86.67% was obtained for five finer-grained activities (excluding breathing) of eight individuals within 6 m behind the wall for the most practical scenario, a significant improvement over the 79% accuracy of the current method. PMID:27314362

  9. Detection and Classification of Finer-Grained Human Activities Based on Stepped-Frequency Continuous-Wave Through-Wall Radar.

    PubMed

    Qi, Fugui; Liang, Fulai; Lv, Hao; Li, Chuantao; Chen, Fuming; Wang, Jianqi

    2016-01-01

    The through-wall detection and classification of human activities are critical for anti-terrorism, security, and disaster rescue operations. An effective through-wall detection and classification technology is proposed for finer-grained human activities such as piaffe, picking up an object, waving, jumping, standing with random micro-shakes, and breathing while sitting. A stepped-frequency continuous wave (SFCW) bio-radar sensor is first used to conduct through-wall detection of finer-grained human activities; Then, a comprehensive range accumulation time-frequency transform (CRATFR) based on inverse weight coefficients is proposed, which aims to strengthen the micro-Doppler features of finer activity signals. Finally, in combination with the effective eigenvalues extracted from the CRATFR spectrum, an optimal self-adaption support vector machine (OS-SVM) based on prior human position information is introduced to classify different finer-grained activities. At a fixed position (3 m) behind a wall, the classification accuracies of six activities performed by eight individuals were 98.78% and 93.23%, respectively, for the two scenarios defined in this paper. In the position-changing experiment, an average classification accuracy of 86.67% was obtained for five finer-grained activities (excluding breathing) of eight individuals within 6 m behind the wall for the most practical scenario, a significant improvement over the 79% accuracy of the current method. PMID:27314362

  10. Grain boundaries

    SciTech Connect

    Balluffi, R.W.; Bristowe, P.D.

    1991-01-01

    The present document is a progress report describing the work accomplished to date during the second year of our four-year grant (February 15, 1990--February 14, 1994) to study grain boundaries. The research was focused on the following three major efforts: Study of the atomic structure of grain boundaries by means of x-ray diffraction, transmission electron microscopy and computer modeling; study of short-circuit diffusion along grain boundaries; and development of a Thin-film Deposition/Bonding Apparatus for the manufacture of high purity bicrystals.

  11. Evaluating the B-cell density with various activation functions using White Noise Path Integral Approach

    NASA Astrophysics Data System (ADS)

    Aban, C. J. G.; Bacolod, R. O.; Confesor, M. N. P.

    2015-06-01

    A The White Noise Path Integral Approach is used in evaluating the B-cell density or the number of B-cell per unit volume for a basic type of immune system response based on the modeling done by Perelson and Wiegel. From the scaling principles of Perelson [1], the B- cell density is obtained where antigens and antibodies mutates and activation function f(|S-SA|) is defined describing the interaction between a specific antigen and a B-cell. If the activation function f(|S-SA|) is held constant, the major form of the B-cell density evaluated using white noise analysis is similar to the form of the B-cell density obtained by Perelson and Wiegel using a differential approach.A piecewise linear functionis also used to describe the activation f(|S-SA|). If f(|S-SA|) is zero, the density decreases exponentially. If f(|S-SA|) = S-SA-SB, the B- cell density increases exponentially until it reaches a certain maximum value. For f(|S-SA|) = 2SA-SB-S, the behavior of B-cell density is oscillating and remains to be in small values.

  12. Linear models of activation cascades: analytical solutions and coarse-graining of delayed signal transduction.

    PubMed

    Beguerisse-Díaz, Mariano; Desikan, Radhika; Barahona, Mauricio

    2016-08-01

    Cellular signal transduction usually involves activation cascades, the sequential activation of a series of proteins following the reception of an input signal. Here, we study the classic model of weakly activated cascades and obtain analytical solutions for a variety of inputs. We show that in the special but important case of optimal gain cascades (i.e. when the deactivation rates are identical) the downstream output of the cascade can be represented exactly as a lumped nonlinear module containing an incomplete gamma function with real parameters that depend on the rates and length of the cascade, as well as parameters of the input signal. The expressions obtained can be applied to the non-identical case when the deactivation rates are random to capture the variability in the cascade outputs. We also show that cascades can be rearranged so that blocks with similar rates can be lumped and represented through our nonlinear modules. Our results can be used both to represent cascades in computational models of differential equations and to fit data efficiently, by reducing the number of equations and parameters involved. In particular, the length of the cascade appears as a real-valued parameter and can thus be fitted in the same manner as Hill coefficients. Finally, we show how the obtained nonlinear modules can be used instead of delay differential equations to model delays in signal transduction.

  13. Linear models of activation cascades: analytical solutions and coarse-graining of delayed signal transduction.

    PubMed

    Beguerisse-Díaz, Mariano; Desikan, Radhika; Barahona, Mauricio

    2016-08-01

    Cellular signal transduction usually involves activation cascades, the sequential activation of a series of proteins following the reception of an input signal. Here, we study the classic model of weakly activated cascades and obtain analytical solutions for a variety of inputs. We show that in the special but important case of optimal gain cascades (i.e. when the deactivation rates are identical) the downstream output of the cascade can be represented exactly as a lumped nonlinear module containing an incomplete gamma function with real parameters that depend on the rates and length of the cascade, as well as parameters of the input signal. The expressions obtained can be applied to the non-identical case when the deactivation rates are random to capture the variability in the cascade outputs. We also show that cascades can be rearranged so that blocks with similar rates can be lumped and represented through our nonlinear modules. Our results can be used both to represent cascades in computational models of differential equations and to fit data efficiently, by reducing the number of equations and parameters involved. In particular, the length of the cascade appears as a real-valued parameter and can thus be fitted in the same manner as Hill coefficients. Finally, we show how the obtained nonlinear modules can be used instead of delay differential equations to model delays in signal transduction. PMID:27581482

  14. Linear models of activation cascades: analytical solutions and coarse-graining of delayed signal transduction

    PubMed Central

    Desikan, Radhika

    2016-01-01

    Cellular signal transduction usually involves activation cascades, the sequential activation of a series of proteins following the reception of an input signal. Here, we study the classic model of weakly activated cascades and obtain analytical solutions for a variety of inputs. We show that in the special but important case of optimal gain cascades (i.e. when the deactivation rates are identical) the downstream output of the cascade can be represented exactly as a lumped nonlinear module containing an incomplete gamma function with real parameters that depend on the rates and length of the cascade, as well as parameters of the input signal. The expressions obtained can be applied to the non-identical case when the deactivation rates are random to capture the variability in the cascade outputs. We also show that cascades can be rearranged so that blocks with similar rates can be lumped and represented through our nonlinear modules. Our results can be used both to represent cascades in computational models of differential equations and to fit data efficiently, by reducing the number of equations and parameters involved. In particular, the length of the cascade appears as a real-valued parameter and can thus be fitted in the same manner as Hill coefficients. Finally, we show how the obtained nonlinear modules can be used instead of delay differential equations to model delays in signal transduction. PMID:27581482

  15. The Effects of Atmosphere on the Sintering of Ultrafine-Grained Tungsten with Ti

    NASA Astrophysics Data System (ADS)

    Ren, Chai; Koopman, Mark; Fang, Z. Zak; Zhang, Huan

    2016-10-01

    Tungsten (W) is a brittle material at room temperature making it very difficult to fabricate. Although the lack of ductility remains a difficult challenge, nano-sized and ultrafine-grained (UFG) structures offer the potential to overcome tungsten's room-temperature brittleness. One way to manufacture UFG W is to compact and sinter nano-sized W powder. It is challenging, however, to control grain growth during sintering. As one method to inhibit grain growth, the effect of Ti-based additives on the densification and grain growth of nano-W powders was investigated in this study. Addition of 1% Ti into tungsten led to more than a 63% decrease in average grain size of sintered samples at comparable density levels. It was found that sintering in Ar yielded a finer grain size than sintering in H2 at similar densities. The active diffusion mechanisms during sintering were different for W-1% Ti nano powders sintered in Ar and H2.

  16. Active site densities, oxygen activation and adsorbed reactive oxygen in alcohol activation on npAu catalysts.

    PubMed

    Wang, Lu-Cun; Friend, C M; Fushimi, Rebecca; Madix, Robert J

    2016-07-01

    The activation of molecular O2 as well as the reactivity of adsorbed oxygen species is of central importance in aerobic selective oxidation chemistry on Au-based catalysts. Herein, we address the issue of O2 activation on unsupported nanoporous gold (npAu) catalysts by applying a transient pressure technique, a temporal analysis of products (TAP) reactor, to measure the saturation coverage of atomic oxygen, its collisional dissociation probability, the activation barrier for O2 dissociation, and the facility with which adsorbed O species activate methanol, the initial step in the catalytic cycle of esterification. The results from these experiments indicate that molecular O2 dissociation is associated with surface silver, that the density of reactive sites is quite low, that adsorbed oxygen atoms do not spill over from the sites of activation onto the surrounding surface, and that methanol reacts quite facilely with the adsorbed oxygen atoms. In addition, the O species from O2 dissociation exhibits reactivity for the selective oxidation of methanol but not for CO. The TAP experiments also revealed that the surface of the npAu catalyst is saturated with adsorbed O under steady state reaction conditions, at least for the pulse reaction. PMID:27376884

  17. Antagonistic activity of Ocimum sanctum L. essential oil on growth and zearalenone production by Fusarium graminearum in maize grains.

    PubMed

    Kalagatur, Naveen K; Mudili, Venkataramana; Siddaiah, Chandranayaka; Gupta, Vijai K; Natarajan, Gopalan; Sreepathi, Murali H; Vardhan, Batra H; Putcha, Venkata L R

    2015-01-01

    The present study was aimed to establish the antagonistic effects of Ocimum sanctum L. essential oil (OSEO) on growth and zearalenone (ZEA) production of Fusarium graminearum. GC-MS chemical profiling of OSEO revealed the existence of 43 compounds and the major compound was found to be eugenol (34.7%). DPPH free radical scavenging activity (IC50) of OSEO was determined to be 8.5 μg/mL. Minimum inhibitory concentration and minimum fungicidal concentration of OSEO on F. graminearum were recorded as 1250 and 1800 μg/mL, respectively. Scanning electron microscope observations showed significant micro morphological damage in OSEO exposed mycelia and spores compared to untreated control culture. Quantitative UHPLC studies revealed that OSEO negatively effected the production of ZEA; the concentration of toxin production was observed to be insignificant at 1500 μg/mL concentration of OSEO. On other hand ZEA concentration was quantified as 3.23 μg/mL in OSEO untreated control culture. Reverse transcriptase qPCR analysis of ZEA metabolic pathway genes (PKS4 and PKS13) revealed that increase in OSEO concentration (250-1500 μg/mL) significantly downregulated the expression of PKS4 and PKS13. These results were in agreement with the artificially contaminated maize grains as well. In conlusion, the antifungal and antimycotoxic effects of OSEO on F. graminearum in the present study reiterated that, the essential oil of O. sanctum could be a promising herbal fungicide in food processing industries as well as grain storage centers. PMID:26388846

  18. Antagonistic activity of Ocimum sanctum L. essential oil on growth and zearalenone production by Fusarium graminearum in maize grains

    PubMed Central

    Kalagatur, Naveen K.; Mudili, Venkataramana; Siddaiah, Chandranayaka; Gupta, Vijai K.; Natarajan, Gopalan; Sreepathi, Murali H.; Vardhan, Batra H.; Putcha, Venkata L. R.

    2015-01-01

    The present study was aimed to establish the antagonistic effects of Ocimum sanctum L. essential oil (OSEO) on growth and zearalenone (ZEA) production of Fusarium graminearum. GC–MS chemical profiling of OSEO revealed the existence of 43 compounds and the major compound was found to be eugenol (34.7%). DPPH free radical scavenging activity (IC50) of OSEO was determined to be 8.5 μg/mL. Minimum inhibitory concentration and minimum fungicidal concentration of OSEO on F. graminearum were recorded as 1250 and 1800 μg/mL, respectively. Scanning electron microscope observations showed significant micro morphological damage in OSEO exposed mycelia and spores compared to untreated control culture. Quantitative UHPLC studies revealed that OSEO negatively effected the production of ZEA; the concentration of toxin production was observed to be insignificant at 1500 μg/mL concentration of OSEO. On other hand ZEA concentration was quantified as 3.23 μg/mL in OSEO untreated control culture. Reverse transcriptase qPCR analysis of ZEA metabolic pathway genes (PKS4 and PKS13) revealed that increase in OSEO concentration (250–1500 μg/mL) significantly downregulated the expression of PKS4 and PKS13. These results were in agreement with the artificially contaminated maize grains as well. In conlusion, the antifungal and antimycotoxic effects of OSEO on F. graminearum in the present study reiterated that, the essential oil of O. sanctum could be a promising herbal fungicide in food processing industries as well as grain storage centers. PMID:26388846

  19. The QTL GNP1 Encodes GA20ox1, Which Increases Grain Number and Yield by Increasing Cytokinin Activity in Rice Panicle Meristems

    PubMed Central

    Mi, Xue-Fei; Shan, Jun-Xiang; Xu, Jian-Long

    2016-01-01

    Cytokinins and gibberellins (GAs) play antagonistic roles in regulating reproductive meristem activity. Cytokinins have positive effects on meristem activity and maintenance. During inflorescence meristem development, cytokinin biosynthesis is activated via a KNOX-mediated pathway. Increased cytokinin activity leads to higher grain number, whereas GAs negatively affect meristem activity. The GA biosynthesis genes GA20oxs are negatively regulated by KNOX proteins. KNOX proteins function as modulators, balancing cytokinin and GA activity in the meristem. However, little is known about the crosstalk among cytokinin and GA regulators together with KNOX proteins and how KNOX-mediated dynamic balancing of hormonal activity functions. Through map-based cloning of QTLs, we cloned a GA biosynthesis gene, Grain Number per Panicle1 (GNP1), which encodes rice GA20ox1. The grain number and yield of NIL-GNP1TQ were significantly higher than those of isogenic control (Lemont). Sequence variations in its promoter region increased the levels of GNP1 transcripts, which were enriched in the apical regions of inflorescence meristems in NIL-GNP1TQ. We propose that cytokinin activity increased due to a KNOX-mediated transcriptional feedback loop resulting from the higher GNP1 transcript levels, in turn leading to increased expression of the GA catabolism genes GA2oxs and reduced GA1 and GA3 accumulation. This rebalancing process increased cytokinin activity, thereby increasing grain number and grain yield in rice. These findings uncover important, novel roles of GAs in rice florescence meristem development and provide new insights into the crosstalk between cytokinin and GA underlying development process. PMID:27764111

  20. Biomass density and filament length synergistically affect activated sludge settling: systematic quantification and modeling.

    PubMed

    Jassby, D; Xiao, Y; Schuler, A J

    2014-01-01

    Settling of the biomass produced during biological treatment of wastewater is a critical and often problematic process. Filamentous bacteria content is the best-known factor affecting biomass settleability in activated sludge wastewater treatment systems, and varying biomass density has recently been shown to play an important role as well. The objective of this study was to systematically determine how filament content and biomass density combine to affect microbial biomass settling, with a focus on density variations over the range found in full-scale systems. A laboratory-scale bioreactor system was operated to produce biomass with a range of filamentous bacterium contents. Biomass density was systematically varied in samples from this system by addition of synthetic microspheres to allow separation of filament content and density effects on settleability. Fluorescent in-situ hybridization indicated that the culture was dominated by Sphaerotilus natans, a common contributor to poor settling in full-scale systems. A simple, image-based metric of filament content (filament length per floc area) was linearly correlated with the more commonly used filament length per dry biomass measurement. A non-linear, semi-empirical model of settleability as a function of filament content and density was developed and evaluated, providing a better understanding of how these two parameters combine to affect settleability. Filament content (length per dry biomass weight) was nearly linearly related to sludge volume index (SVI) values, with a slightly decreasing differential, and biomass density exhibited an asymptotic relationship with SVI. The filament content associated with bulking was shown to be a function of biomass density. The marginal effect of filament content on settleability increased with decreasing biomass density (low density biomass was more sensitive to changes in filament content than was high density biomass), indicating a synergistic relationship between these

  1. Cometary grains

    NASA Technical Reports Server (NTRS)

    Baum, William A.; Kreidl, Tobias J.; Schleicher, David G.

    1992-01-01

    CCD observations of cometary comas in the spectral continuum are reported. Radial brightness profiles of 14 comets and isophotal maps of three are presented. For 10 of the 14, the azimuthally averaged brightness in the vicinity of the nucleus falls off faster than rho exp -1, where rho is the projected radial distance from the nucleus in the plane of the sky. Simple modeling is used to show that radiation pressure alone cannot account for the observed departures from rho exp -1; it is postulated that the grains fade, i.e., decrease in albedo or size, while they glow outward. For only three of the comets no evidence was found of any grain fading at all. Cases with the most rapid grain fading occurred at small heliocentric distances, but so did some of the cases with no fading, from which large intrinsic differences from comet to comet in the nature of the grain population are inferred.

  2. High power density aqueous hybrid supercapacitor combining activated carbon and highly conductive spinel cobalt oxide

    NASA Astrophysics Data System (ADS)

    Godillot, G.; Taberna, P.-L.; Daffos, B.; Simon, P.; Delmas, C.; Guerlou-Demourgues, L.

    2016-11-01

    The remarkable electrochemical behavior of complete activated carbon/cobalt oxide cells is reported in the present work. Among the various weight ratios between the positive and negative electrodes evaluated, the best features are obtained with an overcapacitive cobalt oxide electrode. The energy densities obtained by this system (20 Wh kg-1 for a power density of 209 W kg-1) are twice higher than those measured for a activated carbon/activated carbon symmetric cell, in the same operating conditions. With discharge capacities around 62 F g-1, this system is among the best ones reported in the literature for this category.

  3. Interstellar grains

    NASA Technical Reports Server (NTRS)

    Snow, T. P.

    1986-01-01

    There are few aspects of interstellar grains that can be unambiguously defined. Very little can be said that is independent of models or presuppositions; hence issues are raised and questions categorized, rather than providing definitive answers. The questions are issues fall into three general areas; the general physical and chemical nature of the grains; the processes by which they are formed and destroyed; and future observational approaches.

  4. Activity of Schinus areira (Anacardiaceae) essential oils against the grain storage pest Tribolium castaneum.

    PubMed

    Descamps, Lilian R; Sánchez Chopa, Carolina; Ferrero, Adriana A

    2011-06-01

    Essential oils extracted from leaves and fruits of Schinus areira (Anacardiaceae) were tested for their repellent, toxic and feeding deterrent properties against Tribolium castaneum (Coleoptera: Tenebrionidae) larvae and adults. A topical application assay was employed for the contact toxicity study and filter paper impregnation for the fumigant assay. A treated diet was also used to evaluate the repellent activity and a flour disk bioassay for the feeding deterrent action and nutritional index alteration. The essential oil of the leaves contained mainly monoterpenoids, with alpha-phellandrene, 3-carene and camphene predominant, whereas that from the fruits contained mainly alpha-phellandrene, 3-carene and beta-myrcene. The leaf essential oil showed repellent effects, whereas that from the fruit was an attractant. Both oils produced mortality against larvae in topical and fumigant bioassays, but fumigant toxicity was not found against adults. Moreover, both essential oils produced some alterations in nutritional index. These results show that the essential oils from S. areira could be applicable to the management of populations of Tribolium castaneum.

  5. Grain physics and infrared dust emission in active galactic nucleus environments

    SciTech Connect

    Hensley, Brandon S.; Ostriker, Jeremiah P.; Ciotti, Luca

    2014-07-01

    We study the effects of a detailed dust treatment on the properties and evolution of early-type galaxies containing central black holes, as determined by active galactic nucleus (AGN) feedback. We find that during cooling flow episodes, radiation pressure on the dust in and interior to infalling shells of cold gas can greatly impact the amount of gas able to be accreted and therefore the frequency of AGN bursts. However, the overall hydrodynamic evolution of all models, including mass budget, is relatively robust to the assumptions on dust. We find that IR re-emission from hot dust can dominate the bolometric luminosity of the galaxy during the early stages of an AGN burst, reaching values in excess of 10{sup 46} erg s{sup –1}. The AGN-emitted UV is largely absorbed, but the optical depth in the IR does not exceed unity, so the radiation momentum input never exceeds L {sub BH}/c. We constrain the viability of our models by comparing the AGN duty cycle, broadband luminosities, dust mass, black hole mass, and other model predictions to current observations. These constraints force us towards models wherein the dust to metals ratios are ≅ 1% of the Galactic value, and only models with a dynamic dust to gas ratio are able to produce both quiescent galaxies consistent with observations and high obscured fractions during AGN 'on' phases. During AGN outbursts, we predict that a large fraction of the FIR luminosity can be attributed to warm dust emission (≅ 100 K) from dense dusty gas within ≤1 kpc reradiating the AGN UV emission.

  6. Chemical composition and insecticidal activity of the essential oil of Illicium pachyphyllum fruits against two grain storage insects.

    PubMed

    Liu, Peng; Liu, Xin-Chao; Dong, Hui-Wen; Liu, Zhi-Long; Du, Shu-Shan; Deng, Zhi-Wei

    2012-12-13

    The aim of this research was to determine chemical composition and insecticidal activity of the essential oil of Illicium pachyphyllum fruits against two grain storage insects, Sitophilus zeamais and Tribolium castaneum, and to isolate any insecticidal constituents from the essential oil. The essential oil of I. pachyphyllum fruits was obtained by hydrodistillation and analyzed by GC-MS. A total of 36 components of the essential oil were identified, with the principal compounds in the essential oil being trans-ρ-mentha-1(7),8-dien-2-ol (24.56%), D-limonene (9.79%), caryophyllene oxide (9.32%), and cis-carveol (5.26%) followed by β-caryophyllene (4.63%) and bornyl acetate. Based on bioactivity-guided fractionation, the three active constituents were isolated and identified as trans-ρ-mentha-1(7),8-dien-2-ol, D-limonene and caryophyllene oxide. The essential oil of I. pachyphyllum fruits exhibited contact toxicity against S. zeamais and T. castaneum adults, with LD(50) values of 17.33 μg/adult and 28.94 μg/adult, respectively. trans-p-Mentha-1(7),8-dien-2-ol (LD(50) = 8.66 μg/adult and 13.66 μg/adult, respectively) exhibited stronger acute toxicity against S. zeamais and T. castaneum adults than either caryophyllene oxide (LD(50) = 34.09 μg/adult and 45.56 μg/adult) and D-limonene (LD(50) = 29.86 μg/adult and 20.14 μg/adult). The essential oil of I. pachyphyllum possessed fumigant toxicity against S. zeamais and T. castaneum adults with LC(50) values of 11.49 mg/L and 15.08 mg/L, respectively. trans-p-Mentha-1(7),8-dien-2-ol exhibited stronger fumigant toxicity against S. zeamais and T. castaneum adults, respectively, with LC(50) values of 6.01 mg/L and 8.14 mg/L, than caryophyllene oxide (LC(50) = 17.02 mg/L and 15.98 mg/L) and D-limonene (LC(50) = 33.71 mg/L and 21.24 mg/L). The results indicate that the essential oil of I. pachyphyllum fruits and its constituent compounds have potential for development into natural insecticides or fumigants for the

  7. Solid-substrate fermentation of wheat grains by mycelia of indigenous species of the genus Ganoderma (higher Basidiomycetes) to enhance the antioxidant activities.

    PubMed

    Subramaniam, Sarasvathy; Sabaratnam, Vikineswary; Kuppusamy, Umah Rani; Tan, Yee Shin

    2014-01-01

    Species of the genus Ganoderma are a cosmopolitan wood decaying white rot fungi, which has been used by the Asians for therapeutic purposes for centuries. In the present study, solid-substrate fermentation (SSF) of wheat grains (Triticum aestivum L.) was carried out with indigenous Ganoderma australe (KUM60813) and G. neo-japonicum (KUM61076) selected based on ethnomycological knowledge. G. lucidum (VITA GL) (a commercial strain) was also included in the study. Antioxidant activities of the crude ethanol and aqueous extracts of the fermented and unfermented wheat grains were investigated by ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC), diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging ability, and lipid peroxidation assay. Among the six mycelia extracts tested, the ethanol extract from wheat fermented with KUM61076 mycelia showed the most potent antioxidant activities, whereas the ethanol extract of wheat grains fermented with KUM60813 mycelia has a good potential in protecting frying oils against oxidation. Total phenolic content (TPC) in the ethanol extracts were higher than that in the aqueous extract. The wheat grains fermented with G. australe (KUM60813) and G. neo-japonicum KUM61076 have greater antioxidant potential compared to the commercially available G. lucidum (VITA GL). The antioxidant activities of the mycelia extracts had a positive correlation with their phenolic contents. Thus phenolic compounds may play a vital role in the antioxidant activities of the selected Ganoderma spp. PMID:24941167

  8. Solid-substrate fermentation of wheat grains by mycelia of indigenous species of the genus Ganoderma (higher Basidiomycetes) to enhance the antioxidant activities.

    PubMed

    Subramaniam, Sarasvathy; Sabaratnam, Vikineswary; Kuppusamy, Umah Rani; Tan, Yee Shin

    2014-01-01

    Species of the genus Ganoderma are a cosmopolitan wood decaying white rot fungi, which has been used by the Asians for therapeutic purposes for centuries. In the present study, solid-substrate fermentation (SSF) of wheat grains (Triticum aestivum L.) was carried out with indigenous Ganoderma australe (KUM60813) and G. neo-japonicum (KUM61076) selected based on ethnomycological knowledge. G. lucidum (VITA GL) (a commercial strain) was also included in the study. Antioxidant activities of the crude ethanol and aqueous extracts of the fermented and unfermented wheat grains were investigated by ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC), diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging ability, and lipid peroxidation assay. Among the six mycelia extracts tested, the ethanol extract from wheat fermented with KUM61076 mycelia showed the most potent antioxidant activities, whereas the ethanol extract of wheat grains fermented with KUM60813 mycelia has a good potential in protecting frying oils against oxidation. Total phenolic content (TPC) in the ethanol extracts were higher than that in the aqueous extract. The wheat grains fermented with G. australe (KUM60813) and G. neo-japonicum KUM61076 have greater antioxidant potential compared to the commercially available G. lucidum (VITA GL). The antioxidant activities of the mycelia extracts had a positive correlation with their phenolic contents. Thus phenolic compounds may play a vital role in the antioxidant activities of the selected Ganoderma spp.

  9. Multi-Cell High Latitude Density Structure Induced by Ion Drag during Active Periods

    NASA Astrophysics Data System (ADS)

    Walterscheid, R. L.; Crowley, G.

    2012-12-01

    During active periods two-cell convection patterns can produce four-cell density structure in the high-latitude thermosphere. During these periods density perturbations approaching 50% are possible. The occurrence of density structures that are more complex than the forcing itself suggests that the structure is caused by a profound change in the balance of forces. Using a General Circulation Model of the thermosphere, we compare the balance of forces in the upper and lower thermosphere during active and quiet times. We also examine the thermal structure caused by the dynamical adjustment to ion-drag forcing in relation to the other terms as a balanced state is approached. Simulations reveal that where ion drag is unable to accelerate the atmosphere into rapid motion (during quiet times or at low thermospheric altitudes) the Coriolis force is the dominant inertial term, and for fixed pressure levels centers of cyclonic motion are (per the usual meteorology relations) colder and denser than the surrounding air, while centers of anticyclonic motion are warmer and less dense. At fixed heights, densities are high in the evening anticyclonic gyre, and low in the dawn cyclonic gyre. However, this situation is radically changed during active periods when the atmosphere is spun up to rapid motion and the centrifugal force resulting from curved trajectories is the dominant inertial force. When this occurs, the high latitude anticyclones and cyclones both become centers of relatively cold high density air at fixed height. Cold low-density centers are found on both the dawn and dusk sides with a trough of low density air over the pole connecting them. This intrusion of low density splits the evening high density region that exists under quiet conditions giving the four cell pattern found by Crowley et al. [1989; 1996a, b]. Crowley, G., J. Schoendorf, R. G. Roble, F. A. Marcos (1996a). Cellular structures in the high latitude lower thermosphere, J. Geophys. Res. 101, 211

  10. Effect of dislocation structure evolution on low-angle grain boundary formation in 7050 aluminum alloy during aging

    NASA Astrophysics Data System (ADS)

    Gu, Wei; Li, Jing-yuan; Wang, Yi-de

    2015-07-01

    The effect of dislocation structure evolution on low-angle grain boundary formation in 7050 aluminum alloy during aging was studied by using optical microscopy, transmission electron microscopy, and electron backscatter diffraction analysis of misorientation angle distribution, cumulative misorientation and geometrically necessary dislocation (GND) density. Experimental results indicate that coarse spindle-shaped grains with the dimension of 200 µm × 80 µm separate into fine equiaxed grains of 20 µm in size as a result of newborn low-angle grain boundaries formed during the aging process. More specifically, the dislocation arrays, which are rearranged and formed due to scattered dislocations during earlier quenching, transform into low-angle grain boundaries with aging time. The relative frequency of 3°-5° low-angle grain boundaries increases to over 30%. The GND density, which describes low-angle grain boundaries with the misorientation angle under 3°, tends to decrease during initial aging. The inhomogeneous distribution of GNDs is affected by grain orientation. A decrease in GND density mainly occurs from 1.83 × 1013 to 4.40 × 1011 m-2 in grains with <111> fiber texture. This is consistent with a decrease of unit cumulative misorientation. Precipitation on grain boundaries and the formation of a precipitation free zone (PFZ) are facilitated due to the eroding activity of the Graff etchant. Consequently, low-angle grain boundaries could be readily viewed by optical microscopy due to an increase in their electric potential difference.

  11. Genomic architecture of alpha-amylase activity in mature rye grain relative to that of preharvest sprouting.

    PubMed

    Masojć, Piotr; Wiśniewska, Magdalena; Łań, Anna; Milczarski, Paweł; Berdzik, Marcin; Pędziwiatr, Daniel; Pol-Szyszko, Magdalena; Gałęza, Monika; Owsianicki, Radosław

    2011-05-01

    Bi-directional selective genotyping (BSG) carried out on two opposite groups of F(9)(541 × Ot1-3) recombinant inbred lines (RILs) with extremely low and extremely high alpha-amylase activities in mature (dry) grain of rye, followed by molecular mapping, revealed a complex system of selection-responsive loci. Three classes of loci controlling alpha-amylase activity were discerned, including four major AAD loci on chromosomes 3R (three loci) and 6RL (one locus) responding to both directions of the disruptive selection, 20 AAR loci on chromosomes 2RL (three loci), 3R (three loci), 4RS (two loci), 5RL (three loci), 6R (two loci) and 7R (seven loci) responding to selection for low alpha-amylase activity and 17 AAE loci on chromosomes 1RL (seven loci), 2RS (two loci), 3R (two loci), 5R (two loci) and 6RL (four loci) affected by selection for high alpha-amylase activity. The majority of the discerned AA loci also showed responsiveness to selection for preharvest sprouting (PHS). Two AAD loci on chromosome arm 3RL coincided with PHSD loci. The AAD locus on chromosome arm 3RS was independent from PHS, whereas that on chromosome 6RL belonged to the PHSR class. AAR-PHSR loci were found on chromosomes 4RS (one locus) and 5R (two loci) and AAE-PHSE loci were identified on chromosomes 1RL (one locus) and 5RL (one locus). Some PHSD loci represented the AAE (chromosomes 1RL, 3RS and 3RL) or AAR classes (chromosome 5RL). AAR and AAE loci not related to PHS were found on chromosomes 1RL, 2R, 3RS, 4R, 6RL and 7RL. On the other hand, several PHS loci (1RL, 3RS, 5RL, 6RS and 7RS) had no effect on alpha-amylase activity. Allele originating from the parental line 541 mapped in six AA loci on chromosomes 2R (two loci), 5R (three loci) and 7R (one locus) exerted opposite effects on PHS and alpha-amylase activity. Differences between the AA and PHS systems of loci may explain the weak correlation between these two traits observed among recombinant inbred lines. Strategies for the

  12. Active zone density is conserved during synaptic growth but impaired in aged mice.

    PubMed

    Chen, Jie; Mizushige, Takafumi; Nishimune, Hiroshi

    2012-02-01

    Presynaptic active zones are essential structures for synaptic vesicle release, but the developmental regulation of their number and maintenance during aging at mammalian neuromuscular junctions (NMJs) remains unknown. Here, we analyzed the distribution of active zones in developing, mature, and aged mouse NMJs by immunohistochemical detection of the active zone-specific protein Bassoon. Bassoon is a cytosolic scaffolding protein essential for the active zone assembly in ribbon synapses and some brain synapses. Bassoon staining showed a punctate pattern in nerve terminals and axons at the nascent NMJ on embryonic days 16.5-18.5. Three-dimensional reconstruction of NMJs revealed that the majority of Bassoon puncta within an NMJ were attached to the presynaptic membrane from postnatal day 0 to adulthood, and colocalized with another active zone protein, Piccolo. During postnatal development, the number of Bassoon puncta increased as the size of the synapses increased. Importantly, the density of Bassoon puncta remained relatively constant from postnatal day 0 to 54 at 2.3 puncta/μm(2) , while the synapse size increased 3.3-fold. However, Bassoon puncta density and signal intensity were significantly attenuated at the NMJs of 27-month-old aged mice. These results suggest that synapses maintain the density of synaptic vesicle release sites while the synapse size changes, but this density becomes impaired during aging.

  13. Unc-51 controls active zone density and protein composition by downregulating ERK signaling

    PubMed Central

    Wairkar, Yogesh P.; Toda, Hirofumi; Mochizuki, Hiroaki; Furukubo-Tokunaga, Katsuo; Tomoda, Toshifumi; DiAntonio, Aaron

    2009-01-01

    Efficient synaptic transmission requires the apposition of neurotransmitter release sites opposite clusters of postsynaptic neurotransmitter receptors. Transmitter is released at active zones, which are composed of a large complex of proteins necessary for synaptic development and function. Many active zone proteins have been identified, but little is known of the mechanisms that ensure that each active zone receives the proper complement of proteins. Here we use a genetic analysis in Drosophila to demonstrate that the serine threonine kinase Unc-51 acts in the presynaptic motoneuron to regulate the localization of the active zone protein Bruchpilot opposite to glutamate receptors at each synapse. In the absence of Unc-51, many glutamate receptor clusters are unapposed to Bruchpilot, and ultrastructural analysis demonstrates that fewer active zones contain dense body T-bars. In addition to the presence of these aberrant synapses, there is also a decrease in the density of all synapses. This decrease in synaptic density and abnormal active zone composition is associated with impaired evoked transmitter release. Mechanistically, Unc-51 inhibits the activity of the MAP kinase ERK to promote synaptic development. In the unc-51 mutant, increased ERK activity leads to the decrease in synaptic density and the absence of Bruchpilot from many synapses. Hence, activated ERK negatively regulates synapse formation, resulting in either the absence of active zones or the formation of active zones without their proper complement of proteins. The Unc-51-dependent inhibition of ERK activity provides a potential mechanism for synapse-specific control of active zone protein composition and release probability. PMID:19144852

  14. Unc-51 controls active zone density and protein composition by downregulating ERK signaling.

    PubMed

    Wairkar, Yogesh P; Toda, Hirofumi; Mochizuki, Hiroaki; Furukubo-Tokunaga, Katsuo; Tomoda, Toshifumi; Diantonio, Aaron

    2009-01-14

    Efficient synaptic transmission requires the apposition of neurotransmitter release sites opposite clusters of postsynaptic neurotransmitter receptors. Transmitter is released at active zones, which are composed of a large complex of proteins necessary for synaptic development and function. Many active zone proteins have been identified, but little is known of the mechanisms that ensure that each active zone receives the proper complement of proteins. Here we use a genetic analysis in Drosophila to demonstrate that the serine threonine kinase Unc-51 acts in the presynaptic motoneuron to regulate the localization of the active zone protein Bruchpilot opposite to glutamate receptors at each synapse. In the absence of Unc-51, many glutamate receptor clusters are unapposed to Bruchpilot, and ultrastructural analysis demonstrates that fewer active zones contain dense body T-bars. In addition to the presence of these aberrant synapses, there is also a decrease in the density of all synapses. This decrease in synaptic density and abnormal active zone composition is associated with impaired evoked transmitter release. Mechanistically, Unc-51 inhibits the activity of the MAP kinase ERK to promote synaptic development. In the unc-51 mutant, increased ERK activity leads to the decrease in synaptic density and the absence of Bruchpilot from many synapses. Hence, activated ERK negatively regulates synapse formation, resulting in either the absence of active zones or the formation of active zones without their proper complement of proteins. The Unc-51-dependent inhibition of ERK activity provides a potential mechanism for synapse-specific control of active zone protein composition and release probability.

  15. Roughness of Grain-scale Frictional Sliding Surfaces in the Actively Creeping Clay Gouge of the San Andreas Fault

    NASA Astrophysics Data System (ADS)

    Hadizadeh, J.; Candela, T.; Renard, F.; Williams, R.

    2011-12-01

    The gouge from 3197.2m measured depth within the active creep interval in the SAFOD borehole is unconsolidated and mainly composed of illite-smectite and Mg-rich-smectite clays interspersed with rounded lithic fragments and serpentinite porphyroclasts. We find evidence of deformation by frictional grain boundary sliding (FGBS) including a hierarchy of finely striated and slickenside surfaces. At the scale of the core sample, first order slip surfaces appear as mode II and III fractures cutting across a second set of slip surfaces that bound sliding grains in an anastomosing or lozenge-shape fabric. To characterize the different sliding orders and establish possible roughness scaling between the FGBS and outcrop-scale slip surfaces, we profiled the first and second order slip surfaces using white light interferometry (WLI) technique. Sample surfaces (10 samples; 20-140 mm2/sample) were differentiated on the basis of morphology and directly extracted from the core sample. Data was collected along 240 profiles using a Zygo NV7300 WLI scanning microscope at 1-2 points/micrometer distance. The 2-D roughness as represented by Hurst exponent (H) was determined via Fourier Power Spectrum, Root Mean Square and Wavelet methods for multiple profiles/surface, parallel (L) and perpendicular (A) to slip striations. The scanned surfaces were mostly strongly self-affine, definable by two Hurst exponents HL and HA. The difference in mean H values (HL-HA) for all measurements were 0.244 and 0.018 for the first and second order surfaces respectively suggesting that the first order surfaces were about 13 times more anisotropic than the second order surfaces. Based on this and previously published results we assume that the higher anisotropy of the first order surfaces is due to greater cumulative slip. The possible explanations are argued as follows. 1. The second order surfaces with larger total surface areas could be preferentially subject to resurfacing by processes such as

  16. Direct imaging of thermally-activated grain-boundary diffusion in Cu/Co/IrMn/Pt exchange-bias structures using atom-probe tomography

    SciTech Connect

    Letellier, F.; Lardé, R.; Le Breton, J.-M.; Akmaldinov, K.; Auffret, S.; Dieny, B.; Baltz, V.

    2014-11-28

    Magnetic devices are often subject to thermal processing steps, such as field cooling to set exchange bias and annealing to crystallize amorphous magnetic electrodes. These processing steps may result in interdiffusion and the subsequent deterioration of magnetic properties. In this study, we investigated thermally-activated diffusion in Cu/Co/IrMn/Pt exchange biased polycrystalline thin-film structures using atom probe tomography. Images taken after annealing at 400 °C for 60 min revealed Mn diffusion into Co grains at the Co/IrMn interface and along Pt grain boundaries for the IrMn/Pt stack, i.e., a Harrison type C regime. Annealing at 500 °C showed further Mn diffusion into Co grains. At the IrMn/Pt interface, annealing at 500 °C led to a type B behavior since Mn diffusion was detected both along Pt grain boundaries and also into Pt grains. The deterioration of the films' exchange bias properties upon annealing was correlated to the observed diffusion. In particular, the topmost Pt capping layer thickness turned out to be crucial since a faster deterioration of the exchange bias properties for thicker caps was observed. This is consistent with the idea that Pt acts as a getter for Mn, drawing Mn out of the IrMn layer.

  17. Direct imaging of thermally-activated grain-boundary diffusion in Cu/Co/IrMn/Pt exchange-bias structures using atom-probe tomography

    NASA Astrophysics Data System (ADS)

    Letellier, F.; Lechevallier, L.; Lardé, R.; Le Breton, J.-M.; Akmaldinov, K.; Auffret, S.; Dieny, B.; Baltz, V.

    2014-11-01

    Magnetic devices are often subject to thermal processing steps, such as field cooling to set exchange bias and annealing to crystallize amorphous magnetic electrodes. These processing steps may result in interdiffusion and the subsequent deterioration of magnetic properties. In this study, we investigated thermally-activated diffusion in Cu/Co/IrMn/Pt exchange biased polycrystalline thin-film structures using atom probe tomography. Images taken after annealing at 400 °C for 60 min revealed Mn diffusion into Co grains at the Co/IrMn interface and along Pt grain boundaries for the IrMn/Pt stack, i.e., a Harrison type C regime. Annealing at 500 °C showed further Mn diffusion into Co grains. At the IrMn/Pt interface, annealing at 500 °C led to a type B behavior since Mn diffusion was detected both along Pt grain boundaries and also into Pt grains. The deterioration of the films' exchange bias properties upon annealing was correlated to the observed diffusion. In particular, the topmost Pt capping layer thickness turned out to be crucial since a faster deterioration of the exchange bias properties for thicker caps was observed. This is consistent with the idea that Pt acts as a getter for Mn, drawing Mn out of the IrMn layer.

  18. Radiation activated CHK1/MEPE pathway may contribute to microgravity-induced bone density loss.

    PubMed

    Zhang, Xiangming; Wang, Ping; Wang, Ya

    2015-11-01

    Bone density loss in astronauts on long-term space missions is a chief medical concern. Microgravity in space is the major cause of bone density loss (osteopenia), and it is believed that high linear energy transfer (LET) radiation in space exacerbates microgravity-induced bone density loss; however, the mechanism remains unclear. It is known that acidic serine- and aspartate-rich motif (ASARM) as a small peptide released by matrix extracellular phosphoglycoprotein (MEPE) promotes osteopenia. We previously discovered that MEPE interacted with checkpoint kinase 1 (CHK1) to protect CHK1 from ionizing radiation promoted degradation. In this study, we addressed whether the CHK1-MEPE pathway activated by radiation contributes to the effects of microgravity on bone density loss. We examined the CHK1, MEPE and secreted MEPE/ASARM levels in irradiated (1 Gy of X-ray) and rotated cultured human osteoblast cells. The results showed that radiation activated CHK1, decreased the levels of CHK1 and MEPE in human osteoblast cells and increased the release of MEPE/ASARM. These results suggest that the radiation-activated CHK1/MEPE pathway exacerbates the effects of microgravity on bone density loss, which may provide a novel targeting factor/pathway for a future countermeasure design that could contribute to reducing osteopenia in astronauts. PMID:26553637

  19. Radiation activated CHK1/MEPE pathway may contribute to microgravity-induced bone density loss

    PubMed Central

    Zhang, Xiangming; Wang, Ping; Wang, Ya

    2016-01-01

    Bone density loss in astronauts on long-term space missions is a chief medical concern. Microgravity in space is the major cause of bone density loss (osteopenia), and it is believed that high linear energy transfer (LET) radiation in space exacerbates microgravity-induced bone density loss; however, the mechanism remains unclear. It is known that acidic serine- and aspartate-rich motif (ASARM) as a small peptide released by matrix extracellular phosphoglycoprotein (MEPE) promotes osteopenia. We previously discovered that MEPE interacted with checkpoint kinase 1 (CHK1) to protect CHK1 from ionizing radiation promoted degradation. In this study, we addressed whether the CHK1-MEPE pathway activated by radiation contributes to the effects of microgravity on bone density loss. We examined the CHK1, MEPE and secreted MEPE/ASARM levels in irradiated (1 Gy of X-ray) and rotated cultured human osteoblast cells. The results showed that radiation activated CHK1, decreased the levels of CHK1 and MEPE in human osteoblast cells and increased the release of MEPE/ASARM. These results suggest that the radiation-activated CHK1/MEPE pathway exacerbates the effects of microgravity on bone density loss, which may provide a novel targeting factor/pathway for a future countermeasure design that could contribute to reducing osteopenia in astronauts. PMID:26553637

  20. Activities of starch hydrolytic enzymes and sucrose-phosphate synthase in the stems of rice subjected to water stress during grain filling.

    PubMed

    Yang, J; Zhang, J; Wang, Z; Zhu, Q

    2001-11-01

    To understand the effect of water stress on the remobilization of prestored carbon reserves, the changes in the activities of starch hydrolytic enzymes and sucrose-phosphate synthase (SPS) in the stems of rice (Oryza sativa L.) during grain filling were investigated. Two rice cultivars, showing high lodging-resistance and slow remobilization, were grown in the field and subjected to well-watered (WW, psi(soil)=0) and water-stressed (WS, psi(soil)=-0.05 MPa) treatments 9 d after anthesis (DAA) till maturity. Leaf water potentials of both cultivars markedly decreased during the day as a result of WS treatment, but completely recovered by early morning. WS treatment accelerated the reduction of starch in the stems, promoted the reallocation of prefixed (14)C from the stems to grains, shortened the grain filling period, and increased the grain filling rate. More soluble sugars including sucrose were accumulated in the stems under WS than under WW treatments. Both alpha- and beta-amylase activities were enhanced by the WS, with the former enhanced more than the latter, and were significantly correlated with the concentrations of soluble sugars in the stems. The other two possible starch-breaking enzymes, alpha-glucosidase and starch phosphorylase, showed no significant differences in the activities between the WW and WS treatments. Water stress also increased the SPS activity that is responsible for sucrose production. Both V(limit) and V(max), the activities of the enzyme at limiting and saturating substrate concentrations, were enhanced and the activation state (V(limit)/V(max)) was also increased as a result of the more significant enhancement of V(limit). The enhanced SPS activity was closely correlated with an increase of sucrose accumulation in the stems. The results suggest that the fast hydrolysis of starch and increased carbon remobilization were attributed to the enhanced alpha-amylase activity and the high activation state of SPS when the rice was subjected

  1. Replacing with whole grains and legumes reduces Lp-PLA2 activities in plasma and PBMCs in patients with prediabetes or T2D1

    PubMed Central

    Kim, Minjoo; Jeung, Se Ri; Jeong, Tae-Sook; Lee, Sang-Hyun; Lee, Jong Ho

    2014-01-01

    To determine dietary effects on circulating lipoprotein-associated phospholipase A2 (Lp-PLA2) activity and enzyme activity in peripheral blood mononuclear cells (PBMCs), 99 patients with impaired fasting glucose, impaired glucose tolerance, or newly-diagnosed T2D were randomly assigned to either a control group (usual diet with refined rice) or the whole grain and legume group. Substitution of whole grains and legumes for refined rice was associated with the replacement of 7% of energy from carbohydrates with energy from protein (about 4%) and fat. After 12 weeks, the whole grain and legume group showed a significant decrease in fasting glucose, insulin, homeostasis model assessment-insulin resistance, hemoglobin A1c, malondialdehyde, plasma Lp-PLA2 activity, and oxidized LDL (ox-LDL), and an increase in LDL particle size. The changes (Δs) in these variables in the whole grain and legume group were significantly different from those in controls after adjustment for the baseline levels. When all subjects were considered, Δ plasma Lp-PLA2 positively correlated with Δ glucose, Δ PBMC Lp-PLA2, Δ ox-LDL, and Δ urinary 8-epi-prostaglandin F2α after being adjusted for confounding factors. The Δ PBMC Lp-PLA2 correlated positively with Δ glucose and Δ ox-LDL, and negatively with Δ LDL particle size and baseline PBMC Lp-PLA2. The substitution of whole grains and legumes for refined rice resulted in a reduction in Lp-PLA2 activities in plasma and PBMCs partly through improved glycemic control, increased consumption of protein relative to carbohydrate, and reduced lipid peroxides. PMID:24904022

  2. Ground beetle (Coleoptera: Carabidae) diversity, activity density, and community structure in a diversified agroecosystem.

    PubMed

    Hummel, J D; Dosdall, L M; Clayton, G W; Harker, K N; O'Donovan, J T

    2012-02-01

    Diversity and abundance of ground beetles (Coleoptera: Carabidae) can be enhanced in vegetable and field intercropping systems, but the complexity of polycultures precludes the application of generalized assumptions of effects for novel intercropping combinations. In a field experiment conducted at Lacombe and Ellerslie, Alberta, Canada, in 2005 and 2006, we investigated the effects of intercropping canola (Brassica napus L.) with wheat (Triticum aestivum L.) on the diversity and community structure of carabid beetles, and on the activity density responses of individual carabid species. Shannon-Wiener diversity index scores and species evenness increased significantly as the proportion of wheat comprising total crop plant populations increased in one site-year of the study, indicating a positive response to enhanced crop plant species evenness in the intercrops, and in that same site-year, ground beetle communities in intercrops shifted to more closely approximate those in wheat monocultures as the percentage of wheat in the intercrops increased. Individual carabid species activity densities showed differing responses to intercropping, although activity densities of some potential root maggot (Delia spp.) (Diptera: Anthomyiidae) predators were greater in intercrops with high proportions of wheat than in canola monocultures. The activity density of Pterostichus melanarius (Illiger), the most abundant species collected, tended to be greater in canola monocultures than high-wheat intercrops or wheat monocultures. We conclude that intercrops of canola and wheat have the potential to enhance populations of some carabid species, therefore possibly exerting increased pressure on some canola insect pests.

  3. Acaricidal and Insecticidal Activities of Essential Oils against a Stored-Food Mite and Stored-Grain Insects.

    PubMed

    Song, Ja-Eun; Kim, Jeong-Moon; Lee, Na-Hyun; Yang, Ji-Yeon; Lee, Hoi-Seon

    2016-01-01

    Twenty plant-derived oils were evaluated for their acaricidal and insecticidal activities against Sitotroga cerealella, Sitophilus oryzae, Sitophilus zeamais, and Tyrophagus putrescentiae adults, by using the fumigant and filter paper diffusion methods. Responses varied with bioassay systems, insect or mite species, plant oils, and exposure time. Based on the 50% lethal dose (LD50) values against S. oryzae and S. zeamais in the fumigant bioassay, Anethum graveolens oil (4.12 and 1.12 μg/cm(3), respectively) induced the highest mortality, followed by Achillea millefolium (21.92 and 14.91 μg/cm(3)) and Eucalyptus dives (28.02 and 24.02 μg/cm(3)) oils, respectively. The most toxic oil based on the 50% lethal concentration values against T. putrescentiae was E. dives (3.13 μg/cm(3)), followed by Melaleuca leucadendron (3.93 μg/cm(3)) and Leptospermum pertersonii (4.41 μg/cm(3)). Neroli birgard oil (1.70 μg/cm(3)) was the most toxic based on the LD50 values against S. cerealella, followed by Citrus aurantium (1.80 μg/cm(3)) and Artemisia vulgaris (1.81 μg/cm(3)). The insecticidal and acaricidal activities of the plant oils in the filter paper diffusion bioassay were similar to those in the fumigant bioassay. In comparison, A. millefolium, A. graveolens, and E. dives oils were more effective against S. oryzae and S. zeamais in the fumigant bioassay than in the contact bioassay. These results indicate that the insecticidal activity of the three plant oils against S. oryzae and S. zeamais may be due to their fumigant action. Acaricidal activities of the A. millefolium, A. graveolens, and E. dives oils against T. putrescentiae were 2.62, 1.11, and 122 times higher than that of benzyl benzoate in the contact bioassay. These results indicate that A. millefolium, A. graveolens, and E. dives oils have potential for development as agents to control stored-grain insects and mites. PMID:26735047

  4. Acaricidal and Insecticidal Activities of Essential Oils against a Stored-Food Mite and Stored-Grain Insects.

    PubMed

    Song, Ja-Eun; Kim, Jeong-Moon; Lee, Na-Hyun; Yang, Ji-Yeon; Lee, Hoi-Seon

    2016-01-01

    Twenty plant-derived oils were evaluated for their acaricidal and insecticidal activities against Sitotroga cerealella, Sitophilus oryzae, Sitophilus zeamais, and Tyrophagus putrescentiae adults, by using the fumigant and filter paper diffusion methods. Responses varied with bioassay systems, insect or mite species, plant oils, and exposure time. Based on the 50% lethal dose (LD50) values against S. oryzae and S. zeamais in the fumigant bioassay, Anethum graveolens oil (4.12 and 1.12 μg/cm(3), respectively) induced the highest mortality, followed by Achillea millefolium (21.92 and 14.91 μg/cm(3)) and Eucalyptus dives (28.02 and 24.02 μg/cm(3)) oils, respectively. The most toxic oil based on the 50% lethal concentration values against T. putrescentiae was E. dives (3.13 μg/cm(3)), followed by Melaleuca leucadendron (3.93 μg/cm(3)) and Leptospermum pertersonii (4.41 μg/cm(3)). Neroli birgard oil (1.70 μg/cm(3)) was the most toxic based on the LD50 values against S. cerealella, followed by Citrus aurantium (1.80 μg/cm(3)) and Artemisia vulgaris (1.81 μg/cm(3)). The insecticidal and acaricidal activities of the plant oils in the filter paper diffusion bioassay were similar to those in the fumigant bioassay. In comparison, A. millefolium, A. graveolens, and E. dives oils were more effective against S. oryzae and S. zeamais in the fumigant bioassay than in the contact bioassay. These results indicate that the insecticidal activity of the three plant oils against S. oryzae and S. zeamais may be due to their fumigant action. Acaricidal activities of the A. millefolium, A. graveolens, and E. dives oils against T. putrescentiae were 2.62, 1.11, and 122 times higher than that of benzyl benzoate in the contact bioassay. These results indicate that A. millefolium, A. graveolens, and E. dives oils have potential for development as agents to control stored-grain insects and mites.

  5. Phenomenology of Abnormal Grain Growth in Systems with Nonuniform Grain Boundary Mobility

    NASA Astrophysics Data System (ADS)

    DeCost, Brian L.; Holm, Elizabeth A.

    2016-07-01

    We have investigated the potential for nonuniform grain boundary mobility to act as a persistence mechanism for abnormal grain growth (AGG) using Monte Carlo Potts model simulations. The model system consists of a single initially large candidate grain embedded in a matrix of equiaxed grains, corresponding to the abnormal growth regime before impingement occurs. We assign a mobility advantage to grain boundaries between the candidate grain and a randomly selected subset of the matrix grains. We observe AGG in systems with physically reasonable fractions of fast boundaries; the probability of abnormal growth increases as the density of fast boundaries increases. This abnormal growth occurs by a series of fast, localized growth events that counteract the tendency of abnormally large grains to grow more slowly than the surrounding matrix grains. Resulting abnormal grains are morphologically similar to experimentally observed abnormal grains.

  6. Physical activity and lifestyle effects on bone mineral density among young adults: sociodemographic and biochemical analysis

    PubMed Central

    Alghadir, Ahmad H.; Gabr, Sami A.; Al-Eisa, Einas

    2015-01-01

    [Purpose] The purpose of this study was to assess the possible role of physical activities, calcium consumption and lifestyle factors in both bone mineral density and bone metabolism indices in 350 young adult volunteers. [Subjects and Methods] All volunteers were recruited for the assessment of lifestyle behaviors and physical activity traits using validated questioners, and bone mineral density (BMD), serum osteocalcin (s-OC), bone-specific alkaline phosphatase (BAP), and calcium were estimated using dual-energy X-ray absorptiometry analysis, and immunoassay techniques. [Results] Male participants showed a significant increase in BMD along with an increase in bone metabolism markers compared with females in all groups. However, younger subjects showed a significant increase in BMD, OC, BAP, and calcium compared with older subjects. Osteoporosis was more common in older subjects linked with abnormal body mass index and waist circumference. Bone metabolism markers correlated positively with BMD, physically activity and negatively with osteoporosis in all stages. Also, moderate to higher calcium and milk intake correlated positively with higher BMD. However, low calcium and milk intake along with higher caffeine, and carbonated beverage consumption, and heavy cigarette smoking showed a negative effect on the status of bone mineral density. Stepwise regression analysis showed that life style factors including physical activity and demographic parameters explained around 58–69.8% of the bone mineral density variation in young adults especially females. [Conclusion] body mass index, physical activity, low calcium consumption, and abnormal lifestyle have role in bone mineral density and prognosis of osteoporosis in young adults. PMID:26311965

  7. Physical activity and lifestyle effects on bone mineral density among young adults: sociodemographic and biochemical analysis.

    PubMed

    Alghadir, Ahmad H; Gabr, Sami A; Al-Eisa, Einas

    2015-07-01

    [Purpose] The purpose of this study was to assess the possible role of physical activities, calcium consumption and lifestyle factors in both bone mineral density and bone metabolism indices in 350 young adult volunteers. [Subjects and Methods] All volunteers were recruited for the assessment of lifestyle behaviors and physical activity traits using validated questioners, and bone mineral density (BMD), serum osteocalcin (s-OC), bone-specific alkaline phosphatase (BAP), and calcium were estimated using dual-energy X-ray absorptiometry analysis, and immunoassay techniques. [Results] Male participants showed a significant increase in BMD along with an increase in bone metabolism markers compared with females in all groups. However, younger subjects showed a significant increase in BMD, OC, BAP, and calcium compared with older subjects. Osteoporosis was more common in older subjects linked with abnormal body mass index and waist circumference. Bone metabolism markers correlated positively with BMD, physically activity and negatively with osteoporosis in all stages. Also, moderate to higher calcium and milk intake correlated positively with higher BMD. However, low calcium and milk intake along with higher caffeine, and carbonated beverage consumption, and heavy cigarette smoking showed a negative effect on the status of bone mineral density. Stepwise regression analysis showed that life style factors including physical activity and demographic parameters explained around 58-69.8% of the bone mineral density variation in young adults especially females. [Conclusion] body mass index, physical activity, low calcium consumption, and abnormal lifestyle have role in bone mineral density and prognosis of osteoporosis in young adults. PMID:26311965

  8. Contribution to the evaluation of density of methane adsorbed on activated carbon.

    PubMed

    Rodríguez-Reinoso, Francisco; Almansa, Cristina; Molina-Sabio, Miguel

    2005-11-01

    The adsorption isotherms of N(2) at -196 degrees C, CO(2) at 0 degrees C, and CH(4) at 25 degrees C on 35 activated carbons with a wide range of micropore volumes and pore size distributions have been compared to evaluate the density of adsorbed methane. Results indicate that methane is adsorbed in the micropores of the activated carbon with a density that is a function of the carbon porosity because methane is packed more compactly in narrow than in wide micropores. An experimental procedure is proposed to evaluate the density in both types of micropores as a function of pressure. Its application to these porous carbons indicates that density of adsorbed methane increases rapidly with pressure on narrow micropores, the increase becoming slower above 1.5 MPa. The value reached at 3 MPa is 0.21 g/cm(3), near that estimated as the limiting value, 0.23 g/cm(3). Density in wide micropores is low, 0.09 g/cm(3) at 3 MPa, but it continuously increases with pressure.

  9. Relationship between the line of density anomaly and the lines of melting, crystallization, cavitation, and liquid spinodal in coarse-grained water models.

    PubMed

    Lu, Jibao; Chakravarty, Charusita; Molinero, Valeria

    2016-06-21

    Liquid water has several anomalous properties, including a non-monotonous dependence of density with temperature and an increase of thermodynamic response functions upon supercooling. Four thermodynamic scenarios have been proposed to explain the anomalies of water, but it is not yet possible to decide between them from experiments because of the crystallization and cavitation of metastable liquid water. Molecular simulations provide a versatile tool to study the anomalies and phase behavior of water, assess their agreement with the phenomenology of water under conditions accessible to experiments, and provide insight into the behavior of water in regions that are challenging to probe in the laboratory. Here we investigate the behavior of the computationally efficient monatomic water models mW and mTIP4P/2005(REM), with the aim of unraveling the relationships between the lines of density extrema in the p-T plane, and the lines of melting, liquid-vapor spinodal and non-equilibrium crystallization and cavitation. We focus particularly on the conditions for which the line of density maxima (LDM) in the liquid emerges and disappears as the pressure is increased. We find that these models present a retracing LDM, same as previously found for atomistic water models and models of other tetrahedral liquids. The low-pressure end of the LDM occurs near the pressure of maximum of the melting line, a feature that seems to be general to models that produce tetrahedrally coordinated crystals. We find that the mW water model qualitatively reproduces several key properties of real water: (i) the LDM is terminated by cavitation at low pressures and by crystallization of ice Ih at high pressures, (ii) the LDM meets the crystallization line close to the crossover in crystallization from ice Ih to a non-tetrahedral four-coordinated crystal, and (iii) the density of the liquid at the crossover in crystallization from ice Ih to a four-coordinated non-tetrahedral crystal coincides with

  10. Relationship between the line of density anomaly and the lines of melting, crystallization, cavitation, and liquid spinodal in coarse-grained water models.

    PubMed

    Lu, Jibao; Chakravarty, Charusita; Molinero, Valeria

    2016-06-21

    Liquid water has several anomalous properties, including a non-monotonous dependence of density with temperature and an increase of thermodynamic response functions upon supercooling. Four thermodynamic scenarios have been proposed to explain the anomalies of water, but it is not yet possible to decide between them from experiments because of the crystallization and cavitation of metastable liquid water. Molecular simulations provide a versatile tool to study the anomalies and phase behavior of water, assess their agreement with the phenomenology of water under conditions accessible to experiments, and provide insight into the behavior of water in regions that are challenging to probe in the laboratory. Here we investigate the behavior of the computationally efficient monatomic water models mW and mTIP4P/2005(REM), with the aim of unraveling the relationships between the lines of density extrema in the p-T plane, and the lines of melting, liquid-vapor spinodal and non-equilibrium crystallization and cavitation. We focus particularly on the conditions for which the line of density maxima (LDM) in the liquid emerges and disappears as the pressure is increased. We find that these models present a retracing LDM, same as previously found for atomistic water models and models of other tetrahedral liquids. The low-pressure end of the LDM occurs near the pressure of maximum of the melting line, a feature that seems to be general to models that produce tetrahedrally coordinated crystals. We find that the mW water model qualitatively reproduces several key properties of real water: (i) the LDM is terminated by cavitation at low pressures and by crystallization of ice Ih at high pressures, (ii) the LDM meets the crystallization line close to the crossover in crystallization from ice Ih to a non-tetrahedral four-coordinated crystal, and (iii) the density of the liquid at the crossover in crystallization from ice Ih to a four-coordinated non-tetrahedral crystal coincides with

  11. Relationship between the line of density anomaly and the lines of melting, crystallization, cavitation, and liquid spinodal in coarse-grained water models

    NASA Astrophysics Data System (ADS)

    Lu, Jibao; Chakravarty, Charusita; Molinero, Valeria

    2016-06-01

    Liquid water has several anomalous properties, including a non-monotonous dependence of density with temperature and an increase of thermodynamic response functions upon supercooling. Four thermodynamic scenarios have been proposed to explain the anomalies of water, but it is not yet possible to decide between them from experiments because of the crystallization and cavitation of metastable liquid water. Molecular simulations provide a versatile tool to study the anomalies and phase behavior of water, assess their agreement with the phenomenology of water under conditions accessible to experiments, and provide insight into the behavior of water in regions that are challenging to probe in the laboratory. Here we investigate the behavior of the computationally efficient monatomic water models mW and mTIP4P/2005REM, with the aim of unraveling the relationships between the lines of density extrema in the p-T plane, and the lines of melting, liquid-vapor spinodal and non-equilibrium crystallization and cavitation. We focus particularly on the conditions for which the line of density maxima (LDM) in the liquid emerges and disappears as the pressure is increased. We find that these models present a retracing LDM, same as previously found for atomistic water models and models of other tetrahedral liquids. The low-pressure end of the LDM occurs near the pressure of maximum of the melting line, a feature that seems to be general to models that produce tetrahedrally coordinated crystals. We find that the mW water model qualitatively reproduces several key properties of real water: (i) the LDM is terminated by cavitation at low pressures and by crystallization of ice Ih at high pressures, (ii) the LDM meets the crystallization line close to the crossover in crystallization from ice Ih to a non-tetrahedral four-coordinated crystal, and (iii) the density of the liquid at the crossover in crystallization from ice Ih to a four-coordinated non-tetrahedral crystal coincides with the

  12. Communication: Active space decomposition with multiple sites: Density matrix renormalization group algorithm

    SciTech Connect

    Parker, Shane M.; Shiozaki, Toru

    2014-12-07

    We extend the active space decomposition method, recently developed by us, to more than two active sites using the density matrix renormalization group algorithm. The fragment wave functions are described by complete or restricted active-space wave functions. Numerical results are shown on a benzene pentamer and a perylene diimide trimer. It is found that the truncation errors in our method decrease almost exponentially with respect to the number of renormalization states M, allowing for numerically exact calculations (to a few μE{sub h} or less) with M = 128 in both cases. This rapid convergence is because the renormalization steps are used only for the interfragment electron correlation.

  13. Evidence for composition variations and impurity segregation at grain boundaries in high current-density polycrystalline K- and Co-doped BaFe{sub 2}As{sub 2} superconductors

    SciTech Connect

    Kim, Yoon-Jun; Weiss, Jeremy D.; Hellstrom, Eric E.; Larbalestier, David C.; Seidman, David N.

    2014-10-20

    Some polycrystalline forms of the K- and Co-doped BaFe{sub 2}As{sub 2} and SrFe{sub 2}As{sub 2} superconductors now have a critical current density (J{sub c}) within a factor of ∼5 of that required for real applications, even though it is known that some grain boundaries (GBs) block current, thus, raising the question of whether this blocking is intrinsic or extrinsically limited by artefacts amenable to improvement by better processing. Herein, we utilize atom-probe tomography (APT) to study the grain and GB composition in high J{sub c} K- and Co-doped BaFe{sub 2}As{sub 2} polycrystals. We find that all GBs studied show significant compositional variations on the scale of a few coherence lengths (ξ), as well as strong segregation of oxygen impurities, which we believe are largely introduced in the starting materials. Importantly, these findings demonstrate that APT enables quantitative analysis of the highest J{sub c} K-doped BaFe{sub 2}As{sub 2} samples, where analytical transmission electron microscopy (TEM) fails because of the great reactivity of thin TEM samples. The observations of major chemical perturbations at GBs make us cautiously optimistic that there is a large extrinsic component to the GB current blocking, which will be ameliorated by better processing, for which APT will likely be a crucial instrument.

  14. Synthesis of Dense, Fine-Grained YIG Ceramics by Two-Step Sintering

    NASA Astrophysics Data System (ADS)

    Li, X. X.; Zhou, J. J.; Deng, J. X.; Zheng, H.; Zheng, L.; Zheng, P.; Qin, H. B.

    2016-10-01

    A two-step sintering (TSS) process has been used to fabricate yttrium iron garnet (YIG) ceramics with high density and fine grain size. The densification, microstructure, and magnetic properties were investigated. The sample prepared by the TSS process with first-step sintering temperature ( T 1) of 1350°C, second-step sintering temperature ( T 2) of 1300°C, and holding time of 18 h had density above 99% of theoretical and exhibited uniform microstructure with small average grain size (2.4 μm). The saturation magnetization ( M S) of this sample reached 27.4 emu/g. These results indicate that the TSS process can effectively suppress grain-boundary migration while maintaining active grain-boundary diffusion to obtain dense, fine-grained YIG ceramics with appropriate magnetic properties.

  15. Synthesis of Dense, Fine-Grained YIG Ceramics by Two-Step Sintering

    NASA Astrophysics Data System (ADS)

    Li, X. X.; Zhou, J. J.; Deng, J. X.; Zheng, H.; Zheng, L.; Zheng, P.; Qin, H. B.

    2016-06-01

    A two-step sintering (TSS) process has been used to fabricate yttrium iron garnet (YIG) ceramics with high density and fine grain size. The densification, microstructure, and magnetic properties were investigated. The sample prepared by the TSS process with first-step sintering temperature (T 1) of 1350°C, second-step sintering temperature (T 2) of 1300°C, and holding time of 18 h had density above 99% of theoretical and exhibited uniform microstructure with small average grain size (2.4 μm). The saturation magnetization (M S) of this sample reached 27.4 emu/g. These results indicate that the TSS process can effectively suppress grain-boundary migration while maintaining active grain-boundary diffusion to obtain dense, fine-grained YIG ceramics with appropriate magnetic properties.

  16. Correlation Between the Extent of Catalytic Activity and Charge Density of Montmorillonites

    NASA Astrophysics Data System (ADS)

    Ertem, Gözen; Steudel, Annett; Emmerich, Katja; Lagaly, Gerhard; Schuhmann, Rainer

    2010-09-01

    The clay mineral montmorillonite is a member of the phyllosilicate group of minerals, which has been detected on martian soil. Montmorillonite catalyzes the condensation of activated monomers to form RNA-like oligomers. Extent of catalysis, that is, the yield of oligomers, and the length of the longest oligomer formed in these reactions widely varies with the source of montmorillonite (i.e., the locality where the mineral is mined). This study was undertaken to establish whether there exists a correlation between the extent of catalytic property and the charge density of montmorillonites. Charge density was determined by saturating the montmorillonites with alkyl ammonium cations that contained increasing lengths of alkyl chains, [CH3-(CH2)n-NH3]+, where n = 3-16 and 18, and then measuring d(001), interlayer spacing of the resulting montmorillonite-alkyl ammonium-montmorillonite complex by X-ray diffractometry (XRD). Results demonstrate that catalytic activity of montmorillonites with lower charge density is superior to that of higher charge density montmorillonite. They produce longer oligomers that contain 9 to 10 monomer units, while montmorillonite with high charge density catalyzes the formation of oligomers that contain only 4 monomer units. The charge density of montmorillonites can also be calculated from the chemical composition if elemental analysis data of the pure mineral are available. In the next mission to Mars, CheMin (Chemistry and Mineralogy), a combined X-ray diffraction/X-ray fluorescence instrument, will provide information on the mineralogical and elemental analysis of the samples. Possible significance of these results for planning the future missions to Mars for the search of organic compounds and extinct or extant life is discussed.

  17. Correlation Between the Extent of Catalytic Activity and Charge Density of Montmorillonites

    PubMed Central

    Steudel, Annett; Emmerich, Katja; Lagaly, Gerhard; Schuhmann, Rainer

    2010-01-01

    Abstract The clay mineral montmorillonite is a member of the phyllosilicate group of minerals, which has been detected on martian soil. Montmorillonite catalyzes the condensation of activated monomers to form RNA-like oligomers. Extent of catalysis, that is, the yield of oligomers, and the length of the longest oligomer formed in these reactions widely varies with the source of montmorillonite (i.e., the locality where the mineral is mined). This study was undertaken to establish whether there exists a correlation between the extent of catalytic property and the charge density of montmorillonites. Charge density was determined by saturating the montmorillonites with alkyl ammonium cations that contained increasing lengths of alkyl chains, [CH3-(CH2)n-NH3]+, where n = 3–16 and 18, and then measuring d(001), interlayer spacing of the resulting montmorillonite-alkyl ammonium-montmorillonite complex by X-ray diffractometry (XRD). Results demonstrate that catalytic activity of montmorillonites with lower charge density is superior to that of higher charge density montmorillonite. They produce longer oligomers that contain 9 to 10 monomer units, while montmorillonite with high charge density catalyzes the formation of oligomers that contain only 4 monomer units. The charge density of montmorillonites can also be calculated from the chemical composition if elemental analysis data of the pure mineral are available. In the next mission to Mars, CheMin (Chemistry and Mineralogy), a combined X-ray diffraction/X-ray fluorescence instrument, will provide information on the mineralogical and elemental analysis of the samples. Possible significance of these results for planning the future missions to Mars for the search of organic compounds and extinct or extant life is discussed. Key Words: Mars—Origin of life—Montmorillonite—Mineral catalysis—Layer charge density—X–ray diffractometry. Astrobiology 10, 743–749. PMID:20854214

  18. Correlation between the extent of catalytic activity and charge density of montmorillonites.

    PubMed

    Ertem, Gözen; Steudel, Annett; Emmerich, Katja; Lagaly, Gerhard; Schuhmann, Rainer

    2010-09-01

    The clay mineral montmorillonite is a member of the phyllosilicate group of minerals, which has been detected on martian soil. Montmorillonite catalyzes the condensation of activated monomers to form RNA-like oligomers. Extent of catalysis, that is, the yield of oligomers, and the length of the longest oligomer formed in these reactions widely varies with the source of montmorillonite (i.e., the locality where the mineral is mined). This study was undertaken to establish whether there exists a correlation between the extent of catalytic property and the charge density of montmorillonites. Charge density was determined by saturating the montmorillonites with alkyl ammonium cations that contained increasing lengths of alkyl chains, [CH₃-(CH₂)(n)-NH₃](+), where n = 3-16 and 18, and then measuring d(₀₀₁), interlayer spacing of the resulting montmorillonite-alkyl ammonium-montmorillonite complex by X-ray diffractometry (XRD). Results demonstrate that catalytic activity of montmorillonites with lower charge density is superior to that of higher charge density montmorillonite. They produce longer oligomers that contain 9 to 10 monomer units, while montmorillonite with high charge density catalyzes the formation of oligomers that contain only 4 monomer units. The charge density of montmorillonites can also be calculated from the chemical composition if elemental analysis data of the pure mineral are available. In the next mission to Mars, CheMin (Chemistry and Mineralogy), a combined X-ray diffraction/X-ray fluorescence instrument, will provide information on the mineralogical and elemental analysis of the samples. Possible significance of these results for planning the future missions to Mars for the search of organic compounds and extinct or extant life is discussed.

  19. Correlation between the extent of catalytic activity and charge density of montmorillonites.

    PubMed

    Ertem, Gözen; Steudel, Annett; Emmerich, Katja; Lagaly, Gerhard; Schuhmann, Rainer

    2010-09-01

    The clay mineral montmorillonite is a member of the phyllosilicate group of minerals, which has been detected on martian soil. Montmorillonite catalyzes the condensation of activated monomers to form RNA-like oligomers. Extent of catalysis, that is, the yield of oligomers, and the length of the longest oligomer formed in these reactions widely varies with the source of montmorillonite (i.e., the locality where the mineral is mined). This study was undertaken to establish whether there exists a correlation between the extent of catalytic property and the charge density of montmorillonites. Charge density was determined by saturating the montmorillonites with alkyl ammonium cations that contained increasing lengths of alkyl chains, [CH₃-(CH₂)(n)-NH₃](+), where n = 3-16 and 18, and then measuring d(₀₀₁), interlayer spacing of the resulting montmorillonite-alkyl ammonium-montmorillonite complex by X-ray diffractometry (XRD). Results demonstrate that catalytic activity of montmorillonites with lower charge density is superior to that of higher charge density montmorillonite. They produce longer oligomers that contain 9 to 10 monomer units, while montmorillonite with high charge density catalyzes the formation of oligomers that contain only 4 monomer units. The charge density of montmorillonites can also be calculated from the chemical composition if elemental analysis data of the pure mineral are available. In the next mission to Mars, CheMin (Chemistry and Mineralogy), a combined X-ray diffraction/X-ray fluorescence instrument, will provide information on the mineralogical and elemental analysis of the samples. Possible significance of these results for planning the future missions to Mars for the search of organic compounds and extinct or extant life is discussed. PMID:20854214

  20. Effects of mine wastewater irrigation on activities of soil enzymes and physiological properties, heavy metal uptake and grain yield in winter wheat.

    PubMed

    Ma, Shou-Chen; Zhang, He-Bing; Ma, Shou-Tian; Wang, Rui; Wang, Gui-Xian; Shao, Yun; Li, Chun-Xi

    2015-03-01

    In China, coal-mining industries are mainly located in the water shortage areas including arid or semiarid areas. Mine wastewater is used for irrigation of agricultural land in these areas. However, few studies have been conducted to address ecological and food safety risks caused by mine wastewater irrigation. In this research, a pot experiment was performed to examine the effects of mine wastewater irrigation on soil enzymes, physiological properties of wheat and potential risks of heavy metal contamination to wheat crop. Plants were subjected to three mine wastewater irrigation treatments: leacheate of coal gangue (T1), coal-washing wastewater (T2) and precipitated coal-washing wastewater (T3). Plants irrigated with well water were taken as the control (CK). The results showed that mine wastewater irrigation caused adverse effects on soil enzymes, physiological properties and grain yield of winter wheat. At anthesis, T1, T2 and T3 treatments significantly reduced the activities of soil enzymes (urease, sucrase and catalase), root activity and net photosynthetic rate of wheat compared to CK. At maturity, grain yield was decreased by 17.8%, 15.4% and 9.8% by T1, T2 and T3, respectively, as compared to that of CK. Importantly, mine wastewater irrigation resulted in accumulation of heavy metals (Cr, Pb, Cu and Zn) in wheat grain. Contents of these heavy metals in grains of winter wheat subjected to mine wastewater irrigation were significantly higher than those in CK. The comprehensive contamination indexes of wheat grain in T1, T2 and T3 all reached high pollution level. Our results showed that mine wastewater irrigation significantly increased the pollution risk of heavy metals, thus unsuitable for crop irrigation. PMID:25562177

  1. Effects of mine wastewater irrigation on activities of soil enzymes and physiological properties, heavy metal uptake and grain yield in winter wheat.

    PubMed

    Ma, Shou-Chen; Zhang, He-Bing; Ma, Shou-Tian; Wang, Rui; Wang, Gui-Xian; Shao, Yun; Li, Chun-Xi

    2015-03-01

    In China, coal-mining industries are mainly located in the water shortage areas including arid or semiarid areas. Mine wastewater is used for irrigation of agricultural land in these areas. However, few studies have been conducted to address ecological and food safety risks caused by mine wastewater irrigation. In this research, a pot experiment was performed to examine the effects of mine wastewater irrigation on soil enzymes, physiological properties of wheat and potential risks of heavy metal contamination to wheat crop. Plants were subjected to three mine wastewater irrigation treatments: leacheate of coal gangue (T1), coal-washing wastewater (T2) and precipitated coal-washing wastewater (T3). Plants irrigated with well water were taken as the control (CK). The results showed that mine wastewater irrigation caused adverse effects on soil enzymes, physiological properties and grain yield of winter wheat. At anthesis, T1, T2 and T3 treatments significantly reduced the activities of soil enzymes (urease, sucrase and catalase), root activity and net photosynthetic rate of wheat compared to CK. At maturity, grain yield was decreased by 17.8%, 15.4% and 9.8% by T1, T2 and T3, respectively, as compared to that of CK. Importantly, mine wastewater irrigation resulted in accumulation of heavy metals (Cr, Pb, Cu and Zn) in wheat grain. Contents of these heavy metals in grains of winter wheat subjected to mine wastewater irrigation were significantly higher than those in CK. The comprehensive contamination indexes of wheat grain in T1, T2 and T3 all reached high pollution level. Our results showed that mine wastewater irrigation significantly increased the pollution risk of heavy metals, thus unsuitable for crop irrigation.

  2. Study on Na layer response to geomagnetic activities based on Odin/OSIRIS Na density data

    NASA Astrophysics Data System (ADS)

    Tsuda, Takuo; Nakamura, Takuji; Hedin, Jonas; Gumbel, Jorg; Hosokawa, Keisuke; Ejiri, Mitsumu K.; Nishiyama, Takanori; Takahashi, Toru

    2016-07-01

    The Na layer is normally distributed from 80 to 110 km, and the height range is corresponding to the ionospheric D and E region. In the polar region, the energetic particles precipitating from the magnetosphere can often penetrate into the E region and even into the D region. Thus, the influence of the energetic particles to the Na layer is one of interests in the aspect of the atmospheric composition change accompanied with the auroral activity. There are several previous studies in this issue. For example, recently, we have reported an initial result on a clear relationship between the electron density increase (due to the energetic particles) and the Na density decrease from observational data sets obtained by Na lidar, EISCAT VHF radar, and optical instruments at Tromsoe, Norway on 24-25 January 2012. However, all of the previous studies had been carried out based on case studies by ground-based lidar observations. In this study, we have performed, for the first time, statistical analysis using Na density data from 2004 to 2009 obtained with the Optical Spectrograph and InfraRed Imager System (OSIRIS) onboard Odin satellite. In the presentation, we will show relationship between the Na density and geomagnetic activities, and its latitudinal variation. Based on these results, the Na layer response to the energetic particles will be discussed.

  3. Activated Microporous Carbon Derived from Almond Shells for High Energy Density Asymmetric Supercapacitors.

    PubMed

    Wu, Chun; Yang, Shaoran; Cai, Junjie; Zhang, Qiaobao; Zhu, Ying; Zhang, Kaili

    2016-06-22

    Via the activation treatment of carbonized almond shells with HNO3 and KOH, activated microporous carbon (AMC-3 and AMC-2) was successfully synthesized. These two AMC electrodes demonstrate remarkable electrochemical behaviors such as high rate capability, high specific capacitance, and excellent cycle stability when serving as electrodes for supercapacitors. More importantly, through the use of a Zn-Ni-Co ternary oxide (ZNCO) positive electrode and the AMC negative electrode, asymmetric supercapacitors (ASC) were assembled that deliver superior energy density (53.3 Wh kg(-1) at a power density of 1126.1 W kg(-1) for ASC-2 and 53.6 Wh kg(-1) at a power density of 1124.5 W kg(-1) for ASC-3) and excellent stability (82.7% and 83.4% specific capacitance retention for ZNCO//AMC ASC-2 and ZNCO//AMC ASC-3, respectively, after 5000 cycles). Through these two methods, low-cost, renewable, and environmentally friendly electrode materials can be provided for high energy density supercapacitors. PMID:27253880

  4. Activated Microporous Carbon Derived from Almond Shells for High Energy Density Asymmetric Supercapacitors.

    PubMed

    Wu, Chun; Yang, Shaoran; Cai, Junjie; Zhang, Qiaobao; Zhu, Ying; Zhang, Kaili

    2016-06-22

    Via the activation treatment of carbonized almond shells with HNO3 and KOH, activated microporous carbon (AMC-3 and AMC-2) was successfully synthesized. These two AMC electrodes demonstrate remarkable electrochemical behaviors such as high rate capability, high specific capacitance, and excellent cycle stability when serving as electrodes for supercapacitors. More importantly, through the use of a Zn-Ni-Co ternary oxide (ZNCO) positive electrode and the AMC negative electrode, asymmetric supercapacitors (ASC) were assembled that deliver superior energy density (53.3 Wh kg(-1) at a power density of 1126.1 W kg(-1) for ASC-2 and 53.6 Wh kg(-1) at a power density of 1124.5 W kg(-1) for ASC-3) and excellent stability (82.7% and 83.4% specific capacitance retention for ZNCO//AMC ASC-2 and ZNCO//AMC ASC-3, respectively, after 5000 cycles). Through these two methods, low-cost, renewable, and environmentally friendly electrode materials can be provided for high energy density supercapacitors.

  5. Interstellar grains within interstellar grains

    NASA Technical Reports Server (NTRS)

    Bernatowicz, Thomas J.; Amari, Sachiko; Zinner, Ernst K.; Lewis, Roy S.

    1991-01-01

    Five interstellar graphite spherules extracted from the Murchison carbonaceous meteorite are studied. The isotopic and elemental compositions of individual particles are investigated with the help of an ion microprobe, and this analysis is augmented with structural studies of ultrathin sections of the grain interiors by transmission electron microscopy. As a result, the following procedure for the formation of the interstellar graphite spherule bearing TiC crystals is inferred: (1) high-temperature nucleation and rapid growth of the graphitic carbon spherule in the atmosphere of a carbon-rich star, (2) nucleation and growth of TiC crystals during continued growth of the graphitic spherule and the accretion of TiC onto the spherule, (3) quenching of the graphite growth process by depletion of C or by isolation of the spherule before other grain types could condense.

  6. Weakened Flexural Strength of Nanocrystalline Nanoporous Gold by Grain Refinement.

    PubMed

    Gwak, Eun-Ji; Kim, Ju-Young

    2016-04-13

    High density of grain boundaries in solid materials generally leads to high strength because grain boundaries act as strong obstacles to dislocation activity. We find that the flexural strength of nanoporous gold of grain size 206 nm is 33.6% lower than that of grain size 238 μm. We prepared three gold-silver precursor alloys, well-annealed, prestrained, and high-energy ball-milled, from which nanoporous gold samples were obtained by the same free-corrosion dealloying process. Ligaments of the same size are formed regardless of precursor alloys, and microstructural aspects of precursor alloys such as crystallographic orientation and grain size is preserved in the dealloying process. While the nanoindentation hardness of three nanoporous golds is independent of microstructural variation, flexural strength of nanocrystalline nanoporous gold is significantly lower than that of nanoporous golds with much larger grain size. We investigate weakening mechanisms of grain boundaries in nanocrystalline nanoporous gold, leading to weakening of flexural strength.

  7. Weakened Flexural Strength of Nanocrystalline Nanoporous Gold by Grain Refinement.

    PubMed

    Gwak, Eun-Ji; Kim, Ju-Young

    2016-04-13

    High density of grain boundaries in solid materials generally leads to high strength because grain boundaries act as strong obstacles to dislocation activity. We find that the flexural strength of nanoporous gold of grain size 206 nm is 33.6% lower than that of grain size 238 μm. We prepared three gold-silver precursor alloys, well-annealed, prestrained, and high-energy ball-milled, from which nanoporous gold samples were obtained by the same free-corrosion dealloying process. Ligaments of the same size are formed regardless of precursor alloys, and microstructural aspects of precursor alloys such as crystallographic orientation and grain size is preserved in the dealloying process. While the nanoindentation hardness of three nanoporous golds is independent of microstructural variation, flexural strength of nanocrystalline nanoporous gold is significantly lower than that of nanoporous golds with much larger grain size. We investigate weakening mechanisms of grain boundaries in nanocrystalline nanoporous gold, leading to weakening of flexural strength. PMID:26982460

  8. Density, distribution, and activity of the ocelot Leopardus pardalis (Carnivora: Felidae) in Southeast Mexican rainforests.

    PubMed

    Pérez-Irineo, Gabriela; Santos-Moreno, Antonio

    2014-12-01

    The ocelot Leopardus pardalis is of particular significance in terrestrial communities due to its ecological role within the group of small-sized felids and as a mesopredator. However, despite the reduction of ocelot habitat in Southeast Mexico, there are still very few ecological studies. This research aimed to contribute with some ecological aspects of the species in this region. For this, 29 camera trap stations were established in a rain forest in Los Chimalapas (an area of 22 km2) during a two years period (March 2011-June, 2013), in Oaxaca state, Southeast Mexico. Data allowed the estimation of the population density, activity pattern, sex ratio, residence time, and spatial distribution. Population density was calculated using Capture-Recapture Models for demographically open populations; besides, circular techniques were used to determine if nocturnal and diurnal activity varied significantly over the seasons, and Multiple Discriminant Analysis was used to determine which of the selected environmental variables best explained ocelot abundance in the region. A total of 103 ocelot records were obtained, with a total sampling effort of 8,529 trap-days. Density of 22-38 individuals/100 km2 was estimated. Ocelot population had a high proportion of transient individuals in the zone (55%), and the sex ratio was statistically equal to 1:1. Ocelot activity was more frequent at night (1:00-6:00h), but it also exhibited diurnal activity throughout the study period. Ocelot spatial distribution was positively affected by the proximity to the village as well as by the amount of prey. The ocelot population here appears to be stable, with a density similar to other regions in Central and South America, which could be attributed to the diversity of prey species and a low degree of disturbance in Los Chimalapas.

  9. Joint Associations of Residential Density and Neighborhood Involvement With Physical Activity Among a Multiethnic Sample of Urban Adults.

    PubMed

    Johnson-Lawrence, Vicki; Schulz, Amy J; Zenk, Shannon N; Israel, Barbara A; Wineman, Jean; Marans, Robert W; Rowe, Zachary

    2015-08-01

    Regular physical activity is associated with improvements in overall health. Although resident involvement in neighborhood social activities is positively associated with physical activity, neighborhood design features, including residential density, have varied associations with physical activity. Using data from a multiethnic sample of 696 adults in Detroit, Michigan, multilevel models were used to examine joint effects of residential density and resident involvement in neighborhood activities in relation to physical activity. We found a marginally significant negative interaction of higher residential density and resident neighborhood involvement. Higher residential density was negatively associated with physical activity, and resident neighborhood involvement was positively associated with physical activity. Our findings suggest that future work incorporate additional neighborhood and individual-level characteristics to understand the complexity of the association between the neighborhood environment, resident social engagement in the neighborhood, and physical activity.

  10. Local and Landscape Correlates of Spider Activity Density and Species Richness in Urban Gardens.

    PubMed

    Otoshi, Michelle D; Bichier, Peter; Philpott, Stacy M

    2015-08-01

    Urbanization is a major threat to arthropod biodiversity and abundance due to reduction and loss of suitable natural habitat. Green spaces and small-scale agricultural areas may provide habitat and resources for arthropods within densely developed cities. We studied spider activity density (a measure of both abundance and degree of movement) and diversity in urban gardens in Santa Cruz, Santa Clara, and Monterey counties in central California, USA. We sampled for spiders with pitfall traps and sampled 38 local site characteristics for 5 mo in 19 garden sites to determine the relative importance of individual local factors. We also analyzed 16 landscape variables at 500-m and 1-km buffers surrounding each garden to determine the significance of landscape factors. We identified individuals from the most common families to species and identified individuals from other families to morphospecies. Species from the families Lycosidae and Gnaphosidae composed 81% of total adult spider individuals. Most of the significant factors that correlated with spider activity density and richness were local rather than landscape factors. Spider activity density and richness increased with mulch cover and flowering plant species, and decreased with bare soil. Thus, changes in local garden management have the potential to promote diversity of functionally important spiders in urban environments. PMID:26314049

  11. Local and Landscape Correlates of Spider Activity Density and Species Richness in Urban Gardens.

    PubMed

    Otoshi, Michelle D; Bichier, Peter; Philpott, Stacy M

    2015-08-01

    Urbanization is a major threat to arthropod biodiversity and abundance due to reduction and loss of suitable natural habitat. Green spaces and small-scale agricultural areas may provide habitat and resources for arthropods within densely developed cities. We studied spider activity density (a measure of both abundance and degree of movement) and diversity in urban gardens in Santa Cruz, Santa Clara, and Monterey counties in central California, USA. We sampled for spiders with pitfall traps and sampled 38 local site characteristics for 5 mo in 19 garden sites to determine the relative importance of individual local factors. We also analyzed 16 landscape variables at 500-m and 1-km buffers surrounding each garden to determine the significance of landscape factors. We identified individuals from the most common families to species and identified individuals from other families to morphospecies. Species from the families Lycosidae and Gnaphosidae composed 81% of total adult spider individuals. Most of the significant factors that correlated with spider activity density and richness were local rather than landscape factors. Spider activity density and richness increased with mulch cover and flowering plant species, and decreased with bare soil. Thus, changes in local garden management have the potential to promote diversity of functionally important spiders in urban environments.

  12. Factors in Daily Physical Activity Related to Calcaneal Mineral Density in Men

    NASA Technical Reports Server (NTRS)

    Hutchinson, Teresa M.; Whalen, Robert T.; Cleek, Tammy M.; Vogel, John M.; Arnaud, Sara B.

    1995-01-01

    To determine the factors in daily physical activity that influence the mineral density of the calcaneus, we recorded walking steps and the type and duration of exercise in 43 healthy 26-to 51-yr-old men. Areal (g/sq cm) calcaneal bone mineral density (CBMD) was measured by single energy x-ray densitometry. Subjects walked a mean (+/- SD) of 7902(+/-2534) steps per day or approximately 3.9(+/-1.2) miles daily. Eight subjects reported no exercise activities. The remaining 35 subjects spent 143(2-772) (median and range) min/wk exercising. Twenty-eight men engaged in exercise activities that generate single leg peak vertical ground reaction forces (GRF(sub z)) of 2 or more body weights (high loaders, HL), and 15 reported exercise or daily activities that typically generate GRF(sub z) less than 1.5 body weights (low loaders, LL). CBMD was 12% higher in HL than LL (0.668 +/- 0.074 g/sq cm vs 0.597 +/- 0.062 g/sq cm, P less than 0.004). In the HL group, CBMD correlated to reported minutes of high load exercise (r = 0.41, P less than 0.03). CBMD was not related to the number of daily walking steps (N = 43, r = 0.03, NS). The results of this study support the concept that the dominant factor in daily physical activity relating to bone mineral density is the participation in site specific high loading activities, i.e., for the calcaneus, high calcaneal loads.

  13. A high-density genetic recombination map of sequence-tagged sites for sorghum, as a framework for comparative structural and evolutionary genomics of tropical grains and grasses.

    PubMed Central

    Bowers, John E; Abbey, Colette; Anderson, Sharon; Chang, Charlene; Draye, Xavier; Hoppe, Alison H; Jessup, Russell; Lemke, Cornelia; Lennington, Jennifer; Li, Zhikang; Lin, Yann-Rong; Liu, Sin-Chieh; Luo, Lijun; Marler, Barry S; Ming, Reiguang; Mitchell, Sharon E; Qiang, Dou; Reischmann, Kim; Schulze, Stefan R; Skinner, D Neil; Wang, Yue-Wen; Kresovich, Stephen; Schertz, Keith F; Paterson, Andrew H

    2003-01-01

    We report a genetic recombination map for Sorghum of 2512 loci spaced at average 0.4 cM ( approximately 300 kb) intervals based on 2050 RFLP probes, including 865 heterologous probes that foster comparative genomics of Saccharum (sugarcane), Zea (maize), Oryza (rice), Pennisetum (millet, buffelgrass), the Triticeae (wheat, barley, oat, rye), and Arabidopsis. Mapped loci identify 61.5% of the recombination events in this progeny set and reveal strong positive crossover interference acting across intervals of density are related to possible centromeric regions and to probable chromosome structural rearrangements between Sorghum bicolor and S. propinquum, but not to variation in levels of intraspecific allelic richness. While cDNA and genomic clones are similarly distributed across the genome, SSR-containing clones show different abundance patterns. Rapidly evolving hypomethylated DNA may contribute to intraspecific genomic differentiation. Nonrandom distribution patterns of multiple loci detected by 357 probes suggest ancient chromosomal duplication followed by extensive rearrangement and gene loss. Exemplifying the value of these data for comparative genomics, we support and extend prior findings regarding maize-sorghum synteny-in particular, 45% of comparative loci fall outside the inferred colinear/syntenic regions, suggesting that many small rearrangements have occurred since maize-sorghum divergence. These genetically anchored sequence-tagged sites will foster many structural, functional and evolutionary genomic studies in major food, feed, and biomass crops. PMID:14504243

  14. Anti-hierarchical evolution of the active galactic nucleus space density in a hierarchical universe

    SciTech Connect

    Enoki, Motohiro; Ishiyama, Tomoaki; Kobayashi, Masakazu A. R.; Nagashima, Masahiro

    2014-10-10

    Recent observations show that the space density of luminous active galactic nuclei (AGNs) peaks at higher redshifts than that of faint AGNs. This downsizing trend in the AGN evolution seems to be contradictory to the hierarchical structure formation scenario. In this study, we present the AGN space density evolution predicted by a semi-analytic model of galaxy and AGN formation based on the hierarchical structure formation scenario. We demonstrate that our model can reproduce the downsizing trend of the AGN space density evolution. The reason for the downsizing trend in our model is a combination of the cold gas depletion as a consequence of star formation, the gas cooling suppression in massive halos, and the AGN lifetime scaling with the dynamical timescale. We assume that a major merger of galaxies causes a starburst, spheroid formation, and cold gas accretion onto a supermassive black hole (SMBH). We also assume that this cold gas accretion triggers AGN activity. Since the cold gas is mainly depleted by star formation and gas cooling is suppressed in massive dark halos, the amount of cold gas accreted onto SMBHs decreases with cosmic time. Moreover, AGN lifetime increases with cosmic time. Thus, at low redshifts, major mergers do not always lead to luminous AGNs. Because the luminosity of AGNs is correlated with the mass of accreted gas onto SMBHs, the space density of luminous AGNs decreases more quickly than that of faint AGNs. We conclude that the anti-hierarchical evolution of the AGN space density is not contradictory to the hierarchical structure formation scenario.

  15. Increased white matter neuron density in a rat model of maternal immune activation - Implications for schizophrenia.

    PubMed

    Duchatel, Ryan J; Jobling, Phillip; Graham, Brett A; Harms, Lauren R; Michie, Patricia T; Hodgson, Deborah M; Tooney, Paul A

    2016-02-01

    Interstitial neurons are located among white matter tracts of the human and rodent brain. Post-mortem studies have identified increased interstitial white matter neuron (IWMN) density in the fibre tracts below the cortex in people with schizophrenia. The current study assesses IWMN pathology in a model of maternal immune activation (MIA); a risk factor for schizophrenia. Experimental MIA was produced by an injection of polyinosinic:polycytidylic acid (PolyI:C) into pregnant rats on gestational day (GD) 10 or GD19. A separate control group received saline injections. The density of neuronal nuclear antigen (NeuN(+)) and somatostatin (SST(+)) IWMNs was determined in the white matter of the corpus callosum in two rostrocaudally adjacent areas in the 12week old offspring of GD10 (n=10) or GD19 polyI:C dams (n=18) compared to controls (n=20). NeuN(+) IWMN density trended to be higher in offspring from dams exposed to polyI:C at GD19, but not GD10. A subpopulation of these NeuN(+) IWMNs was shown to express SST. PolyI:C treatment of dams induced a significant increase in the density of SST(+) IWMNs in the offspring when delivered at both gestational stages with more regionally widespread effects observed at GD19. A positive correlation was observed between NeuN(+) and SST(+) IWMN density in animals exposed to polyI:C at GD19, but not controls. This is the first study to show that MIA increases IWMN density in adult offspring in a similar manner to that seen in the brain in schizophrenia. This suggests the MIA model will be useful in future studies aimed at probing the relationship between IWMNs and schizophrenia.

  16. Increased white matter neuron density in a rat model of maternal immune activation - Implications for schizophrenia.

    PubMed

    Duchatel, Ryan J; Jobling, Phillip; Graham, Brett A; Harms, Lauren R; Michie, Patricia T; Hodgson, Deborah M; Tooney, Paul A

    2016-02-01

    Interstitial neurons are located among white matter tracts of the human and rodent brain. Post-mortem studies have identified increased interstitial white matter neuron (IWMN) density in the fibre tracts below the cortex in people with schizophrenia. The current study assesses IWMN pathology in a model of maternal immune activation (MIA); a risk factor for schizophrenia. Experimental MIA was produced by an injection of polyinosinic:polycytidylic acid (PolyI:C) into pregnant rats on gestational day (GD) 10 or GD19. A separate control group received saline injections. The density of neuronal nuclear antigen (NeuN(+)) and somatostatin (SST(+)) IWMNs was determined in the white matter of the corpus callosum in two rostrocaudally adjacent areas in the 12week old offspring of GD10 (n=10) or GD19 polyI:C dams (n=18) compared to controls (n=20). NeuN(+) IWMN density trended to be higher in offspring from dams exposed to polyI:C at GD19, but not GD10. A subpopulation of these NeuN(+) IWMNs was shown to express SST. PolyI:C treatment of dams induced a significant increase in the density of SST(+) IWMNs in the offspring when delivered at both gestational stages with more regionally widespread effects observed at GD19. A positive correlation was observed between NeuN(+) and SST(+) IWMN density in animals exposed to polyI:C at GD19, but not controls. This is the first study to show that MIA increases IWMN density in adult offspring in a similar manner to that seen in the brain in schizophrenia. This suggests the MIA model will be useful in future studies aimed at probing the relationship between IWMNs and schizophrenia. PMID:26385575

  17. Living Clusters and Crystals from Low-Density Suspensions of Active Colloids

    NASA Astrophysics Data System (ADS)

    Mognetti, B. M.; Šarić, A.; Angioletti-Uberti, S.; Cacciuto, A.; Valeriani, C.; Frenkel, D.

    2013-12-01

    Recent studies aimed at investigating artificial analogs of bacterial colonies have shown that low-density suspensions of self-propelled particles confined in two dimensions can assemble into finite aggregates that merge and split, but have a typical size that remains constant (living clusters). In this Letter, we address the problem of the formation of living clusters and crystals of active particles in three dimensions. We study two systems: self-propelled particles interacting via a generic attractive potential and colloids that can move toward each other as a result of active agents (e.g., by molecular motors). In both cases, fluidlike “living” clusters form. We explain this general feature in terms of the balance between active forces and regression to thermodynamic equilibrium. This balance can be quantified in terms of a dimensionless number that allows us to collapse the observed clustering behavior onto a universal curve. We also discuss how active motion affects the kinetics of crystal formation.

  18. Electron density estimation in cold magnetospheric plasmas with the Cluster Active Archive

    NASA Astrophysics Data System (ADS)

    Masson, A.; Pedersen, A.; Taylor, M. G.; Escoubet, C. P.; Laakso, H. E.

    2009-12-01

    Electron density is a key physical quantity to characterize any plasma medium. Its measurement is thus essential to understand the various physical processes occurring in the environment of a magnetized planet. However, any magnetosphere of the solar system is far from being an homogeneous medium with a constant electron density and temperature. For instance, the Earth’s magnetosphere is composed of a variety of regions with densities and temperatures spanning over at least 6 decades of magnitude. For this reason, different types of scientific instruments are usually carried onboard a magnetospheric spacecraft to estimate in situ the electron density of the various plasma regions crossed by different means. In the case of the European Space Agency Cluster mission, five different instruments on each of its four identical spacecraft can be used to estimate it: two particle instruments, a DC electric field instrument, a relaxation sounder and a high-time resolution passive wave receiver. Each of these instruments has its pros and cons depending on the plasma conditions. The focus of this study is the accurate estimation of the electron density in cold plasma regions of the magnetosphere including the magnetotail lobes (Ne ≤ 0.01 e-/cc, Te ~ 100 eV) and the plasmasphere (Ne> 10 e-/cc, Te <10 eV). In these regions, particle instruments can be blind to low energy ions outflowing from the ionosphere or measuring only a portion of the energy range of the particles due to photoelectrons. This often results in an under estimation of the bulk density. Measurements from a relaxation sounder enables accurate estimation of the bulk electron density above a fraction of 1 e-/cc but requires careful calibration of the resonances and/or the cutoffs detected. On Cluster, active soundings enable to derive precise density estimates between 0.2 and 80 e-/cc every minute or two. Spacecraft-to-probe difference potential measurements from a double probe electric field experiment can be

  19. Cell culture density affects the proliferation activity of human adipose tissue stem cells.

    PubMed

    Kim, Dae Seong; Lee, Myoung Woo; Ko, Young Jong; Chun, Yong Hoon; Kim, Hyung Joon; Sung, Ki Woong; Koo, Hong Hoe; Yoo, Keon Hee

    2016-01-01

    In this study, we investigated the effect of cell density on the proliferation activity of human mesenchymal stem cells (MSCs) derived from adipose tissue (AT-MSCs) over time in culture. Passage #4 (P4) and #12 (P12) AT-MSCs from two donors were plated at a density of 200 (culture condition 1, CC1) or 5000 (culture condition 2, CC2) cells cm(-2) . After 7 days of incubation, P4 and P12 AT-MSCs cultured in CC1 were thin and spindle-shaped, whereas those cultured in CC2 had extensive cell-to-cell contacts and an expanded cell volume. In addition, P4 and P12 AT-MSCs in CC1 divided more than three times, while those in CC2 divided less than once on average. Flow cytometric analysis using 5(6)-carboxyfluorescein diacetate N-succinimidyl ester dye showed that the fluorescence intensity of AT-MSCs was lower in CC1 than in CC2. Furthermore, expression of proliferation-associated genes, such as CDC45L, CDC20A and KIF20A, in P4 AT-MSCs was higher in CC1 than in CC2, and this difference was also observed in P12 AT-MSCs. These data demonstrated that cell culture density affects the proliferation activity of MSCs, suggesting that it is feasible to design a strategy to prepare suitable MSCs using specific culture conditions.

  20. Grain boundaries and surfaces in polycrystalline photovoltaics

    NASA Astrophysics Data System (ADS)

    Haney, Paul; Yoon, Heayoung; Zhitenev, Nikolai

    Despite the fact that polycrystalline photovoltaics materials such as CdTe and CIGS are an established commercial technology, the precise role of grain boundaries in their performance remains poorly understood. The high defect density at grain boundaries is generally detrimental to carrier lifetime, however the electric fields surrounding charged grain boundaries may separate electrons and holes, effectively passivating the grain boundary. One difficulty in ascertaining the properties of grain boundaries is that high spatial resolution experimental techniques needed to probe individual grain boundaries are generally surface sensitive. For this reason, extracting quantitative grain boundary and other material properties from this data requires a quantitatively accurate model of the exposed surface. Motivated by these considerations, we present a theoretical analysis of the response of a polycrystalline semiconductor to a localized excitation near a grain boundary, and near the surface. We use our analytical results to interpret electron beam induced current (EBIC) data on polycrystalline CdTe solar cells.

  1. Shear-Coupled Grain Growth and Texture Development in a Nanocrystalline Ni-Fe Alloy during Cold Rolling

    NASA Astrophysics Data System (ADS)

    Li, Li; Ungár, Tamás; Toth, Laszlo S.; Skrotzki, Werner; Wang, Yan Dong; Ren, Yang; Choo, Hahn; Fogarassy, Zsolt; Zhou, X. T.; Liaw, Peter K.

    2016-09-01

    The evolution of texture, grain size, grain shape, dislocation, and twin density has been determined by synchrotron X-ray diffraction and line profile analysis in a nanocrystalline Ni-Fe alloy after cold rolling along different directions related to the initial fiber and the long axis of grains. The texture evolution has been simulated by the Taylor-type relaxed-constraints viscoplastic polycrystal model. The simulations were based on the activity of partial dislocations in correlation with the experimental results of dislocation density determination. The concept of stress-induced shear coupling is supported and strengthened by both the texture simulations and the experimentally determined evolution of the microstructure parameters. Grain growth and texture evolution are shown to proceed by the shear coupling mechanism supported by dislocation activity as long as the grain size is not smaller than about 20 nm.

  2. Tissue-type plasminogen activator suppresses activated stellate cells through low-density lipoprotein receptor-related protein 1.

    PubMed

    Kang, Liang-I; Isse, Kumiko; Koral, Kelly; Bowen, William C; Muratoglu, Selen; Strickland, Dudley K; Michalopoulos, George K; Mars, Wendy M

    2015-10-01

    Hepatic stellate cell (HSC) activation and trans-differentiation into myofibroblast (MFB)-like cells is key for fibrogenesis after liver injury and a potential therapeutic target. Recent studies demonstrated that low-density lipoprotein receptor-related protein 1 (LRP1)-dependent signaling by tissue-type plasminogen activator (t-PA) is a pro-fibrotic regulator of the MFB phenotype in kidney. This study investigated whether LRP1 signaling by t-PA is also relevant to HSC activation following injury. Primary and immortalized rat HSCs were treated with t-PA and assayed by western blot, MTT, and TUNEL. In vitro results were then verified using an in vivo, acute carbon tetrachloride (CCl4) injury model that examined the phenotype and recovery kinetics of MFBs from wild-type animals vs mice with a global (t-PA) or HSC-targeted (LRP1) deletion. In vitro, in contrast to kidney MFBs, exogenous, proteolytically inactive t-PA suppressed, rather than induced, activation markers in HSCs following phosphorylation of LRP1. This process was mediated by LRP1 as inhibition of t-PA binding to LRP1 blocked the effects of t-PA. In vivo, following acute injury, phosphorylation of LRP1 on activated HSCs occurred immediately prior to their disappearance. Mice lacking t-PA or LRP1 retained higher densities of activated HSCs for a longer time period compared with control mice after injury cessation. Hence, t-PA, an FDA-approved drug, contributes to the suppression of activated HSCs following injury repair via signaling through LRP1. This renders t-PA a potential target for exploitation in treating patients with fibrosis.

  3. Controlling activation site density by low-energy far-field stimulation in cardiac tissue.

    PubMed

    Hörning, Marcel; Takagi, Seiji; Yoshikawa, Kenichi

    2012-06-01

    Tachycardia and fibrillation are potentially fatal arrhythmias associated with the formation of rotating spiral waves in the heart. Presently, the termination of these types of arrhythmia is achieved by use of antitachycardia pacing or cardioversion. However, these techniques have serious drawbacks, in that they either have limited application or produce undesirable side effects. Low-energy far-field stimulation has recently been proposed as a superior therapy. This proposed therapeutic method would exploit the phenomenon in which the application of low-energy far-field shocks induces a large number of activation sites ("virtual electrodes") in tissue. It has been found that the formation of such sites can lead to the termination of undesired states in the heart and the restoration of normal beating. In this study we investigate a particular aspect of this method. Here we seek to determine how the activation site density depends on the applied electric field through in vitro experiments carried out on neonatal rat cardiac tissue cultures. The results indicate that the activation site density increases exponentially as a function of the intracellular conductivity and the level of cell isotropy. Additionally, we report numerical results obtained from bidomain simulations of the Beeler-Reuter model that are quantitatively consistent with our experimental results. Also, we derive an intuitive analytical framework that describes the activation site density and provides useful information for determining the ratio of longitudinal to transverse conductivity in a cardiac tissue culture. The results obtained here should be useful in the development of an actual therapeutic method based on low-energy far-field pacing. In addition, they provide a deeper understanding of the intrinsic properties of cardiac cells.

  4. Controlling activation site density by low-energy far-field stimulation in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Hörning, Marcel; Takagi, Seiji; Yoshikawa, Kenichi

    2012-06-01

    Tachycardia and fibrillation are potentially fatal arrhythmias associated with the formation of rotating spiral waves in the heart. Presently, the termination of these types of arrhythmia is achieved by use of antitachycardia pacing or cardioversion. However, these techniques have serious drawbacks, in that they either have limited application or produce undesirable side effects. Low-energy far-field stimulation has recently been proposed as a superior therapy. This proposed therapeutic method would exploit the phenomenon in which the application of low-energy far-field shocks induces a large number of activation sites (“virtual electrodes”) in tissue. It has been found that the formation of such sites can lead to the termination of undesired states in the heart and the restoration of normal beating. In this study we investigate a particular aspect of this method. Here we seek to determine how the activation site density depends on the applied electric field through in vitro experiments carried out on neonatal rat cardiac tissue cultures. The results indicate that the activation site density increases exponentially as a function of the intracellular conductivity and the level of cell isotropy. Additionally, we report numerical results obtained from bidomain simulations of the Beeler-Reuter model that are quantitatively consistent with our experimental results. Also, we derive an intuitive analytical framework that describes the activation site density and provides useful information for determining the ratio of longitudinal to transverse conductivity in a cardiac tissue culture. The results obtained here should be useful in the development of an actual therapeutic method based on low-energy far-field pacing. In addition, they provide a deeper understanding of the intrinsic properties of cardiac cells.

  5. An empirical model to estimate density of sodium hydroxide solution: An activator of geopolymer concretes

    NASA Astrophysics Data System (ADS)

    Rajamane, N. P.; Nataraja, M. C.; Jeyalakshmi, R.; Nithiyanantham, S.

    2016-02-01

    Geopolymer concrete is zero-Portland cement concrete containing alumino-silicate based inorganic polymer as binder. The polymer is obtained by chemical activation of alumina and silica bearing materials, blast furnace slag by highly alkaline solutions such as hydroxide and silicates of alkali metals. Sodium hydroxide solutions of different concentrations are commonly used in making GPC mixes. Often, it is seen that sodium hydroxide solution of very high concentration is diluted with water to obtain SHS of desired concentration. While doing so it was observed that the solute particles of NaOH in SHS tend to occupy lower volumes as the degree of dilution increases. This aspect is discussed in this paper. The observed phenomenon needs to be understood while formulating the GPC mixes since this influences considerably the relationship between concentration and density of SHS. This paper suggests an empirical formula to relate density of SHS directly to concentration expressed by w/w.

  6. Thermospheric topside neutral density, ionospheric anomalous electric field and resistivity measurements by active experiment at EISCAT

    NASA Astrophysics Data System (ADS)

    Kosch, Michael; Ogawa, Yasunobu; Rietveld, Michael; Blagoveshchenskaya, Nataly; Yamazaki, Yosuke

    2016-07-01

    We have developed an active ground-based technique to estimate the topside thermospheric neutral density as well as topside ionospheric anomalous electric field and resistivity at EISCAT, combining the EISCAT UHF radar, HF heater and optics. When pumping the ionosphere the F-region electron temperature is significantly raised, increasing the upward plasma pressure gradient in the topside ionosphere, resulting in observed ion up-flow along the magnetic field line. Simultaneously, pump-induced suprathermal electrons produce artificial optical emissions. Using the modified ion-momentum equation, the thermospheric neutral density is estimated. Alternatively, using the MSIS model the field-aligned anomalous electric field is estimated. From the optical data the suprathermal electron flux is estimated, giving an estimate of the anomalous resistivity. Results from recent observations at EISCAT are presented.

  7. A High Power Density Single-Phase PWM Rectifier With Active Ripple Energy Storage

    SciTech Connect

    Wang, Ruxi; Wang, Fei; Boroyevich, Dushan; Burgos, Rolando; Lai, Rixin; Ning, Puqi; Rajashekara, Kaushik

    2011-01-01

    It is well known that single-phase pulse width modulation rectifiers have second-order harmonic currents and corresponding ripple voltages on the dc bus. The low-frequency harmonic current is normally filtered using a bulk capacitor in the bus, which results in low power density. However, pursuing high power density in converter design is a very important goal in the aerospace applications. This paper studies methods for reducing the energy storage capacitor for single-phase rectifiers. The minimum ripple energy storage requirement is derived independently of a specific topology. Based on theminimum ripple energy requirement, the feasibility of the active capacitor s reduction schemes is verified. Then, we propose a bidirectional buck boost converter as the ripple energy storage circuit, which can effectively reduce the energy storage capacitance. The analysis and design are validated by simulation and experimental results.

  8. Electron Density of Active Region Outflows Measured by the EUV Imaging Spectrometer on board Hinode

    NASA Astrophysics Data System (ADS)

    Kitagawa, N.; Yokoyama, T.

    2015-06-01

    In order to better understand the nature of active region outflows, the electron density was measured by using a density-sensitive line pair, Fe xiv 264.78 Å/274.20 Å. Because coronal line profiles of the outflow region are composed of a major component with a Doppler shift of ≤slant 10 km {{s}-1} and a minor component (enhanced blue wing, EBW) blueshifted by up to 100 km {{s}-1}, we extracted EBW from the line profiles through double-Gaussian fitting. We tried applying the simultaneous fitting to those two Fe xiv lines with several physical restrictions. Electron density for both components ({{n}Major} and {{n}EBW}, respectively) was calculated by referring to the theoretical intensity ratio as a function of electron density as per the CHIANTI database. We studied six locations in the outflow regions around NOAA AR10978. The average electron density was {{n}Major}={{10}9.16+/- 0.16} c{{m}-3} and {{n}EBW}={{10}8.74+/- 0.29} c{{m}-3}. The magnitude relationship between {{n}Major} and {{n}EBW} was the opposite in the eastern and western outflow regions. The column depth was also calculated for each component, which leads to the result that the outflows possess only a small fraction (∼0.1) in the eastern region, whereas they dominate over the major component in the line profiles by a factor of five in the western region. When taking into account the extended coronal structures, the western region can be thought to represent the mass leakage. In contrast, we suggest a possibility that the eastern region actually contributes to mass supply to coronal loops.

  9. Bone Geometry, Density and Strength Indices of the Distal Radius Reflect Loading via Childhood Gymnastic Activity

    PubMed Central

    Dowthwaite, Jodi N.; Flowers, Portia P.E.; Spadaro, Joseph A.; Scerpella, Tamara A.

    2007-01-01

    The distal radius bears unique forces during gymnastic activity. Its relatively simple anatomy, minimal soft tissue envelope and varied composition make the distal radius ideal for evaluating the effects of loading on bone properties. For 56 premenarcheal gymnasts and non-gymnasts, ultradistal and 1/3 distal radius DXA scans measured bone mineral content (BMC), areal bone mineral density and projected area. Simplified geometric models were used to generate bone mineral apparent density (BMAD), geometric indices, strength indices and fall strength ratios. Ratios of regional BMC vs. total body fat free mass (FFM) were calculated. Separate Tanner I and II analyses of covariance adjusted bone parameters for age and height. Ratios were compared using maturity-matched analyses of variance. At the 1/3 region, periosteal width, BMC, cortical cross-sectional area, and section modulus were greater in gymnasts than non-gymnasts (p<0.05); 1/3 BMAD means were equivalent. Ultradistal BMAD, BMC and index for structural strength in axial compression were higher in gymnasts than non-gymnasts; ultradistal periosteal width was only larger in Tanner I gymnasts. Fall strength ratios and BMC/FFM ratios were greater in gymnasts (p<0.05). Geometric and volumetric responses to mechanical loading are site-specific during late childhood and early adolescence. The distal radius bears unique forces during gymnastic activity, and fan beam magnification error is negligible at this site, making it ideal for DXA evaluation of associated bone properties. For 56 premenarcheal gymnasts and non-gymnasts, ultradistal and 1/3 distal radius DXA scans measured bone mineral content, areal bone mineral density and projected area. Simplified geometric models were used to generate bone mineral apparent density, geometric indices, strength indices and fall strength ratios. Ratios of regional bone mineral content vs. total body fat free mass were calculated. Separate Tanner I and II analyses of covariance

  10. Nano-analysis of grain boundary and triple junction transport in nanocrystalline Ni/Cu.

    PubMed

    Reda Chellali, Mohammed; Balogh, Zoltan; Schmitz, Guido

    2013-09-01

    Nanocrystalline materials are distinguished by a high density of structural defects and grain boundaries. Due to the small grain size, a particular defect of the grain boundary topology, the so-called triple junction takes a dominant role for grain growth and atomic transport. We demonstrate by atom probe tomography that triple junctions in nanocrystalline Cu have 100-300 times higher diffusivity of Ni than standard high angle grain boundaries. Also, a previously unexpected systematic variation of the grain boundary width with temperature is detected. The impurity segregation layer at the grain boundaries grows from the 0.7 nm at 563 K to 2.5 nm at 643 K. This variation is clearly not controlled by simple bulk diffusion. Taking this effect into consideration, the activation energies for Ni diffusion in triple junctions and grain boundaries in Cu can be determined to be (83 ± 10) and (120 ± 15) kJ/mol, respectively. Thus, triple junctions are distinguished by considerably lower activation energy with respect to grain boundaries.

  11. Joint Associations of Residential Density and Neighborhood Involvement with Physical Activity among a Multiethnic Sample of Urban Adults

    ERIC Educational Resources Information Center

    Johnson-Lawrence, Vicki; Schulz, Amy J.; Zenk, Shannon N.; Israel, Barbara A.; Wineman, Jean; Marans, Robert W.; Rowe, Zachary

    2015-01-01

    Regular physical activity is associated with improvements in overall health. Although resident involvement in neighborhood social activities is positively associated with physical activity, neighborhood design features, including residential density, have varied associations with physical activity. Using data from a multiethnic sample of 696…

  12. Low-density lipoprotein antioxidant activity of phenolic compounds and polyphenol oxidase activity in selected clingstone peach cultivars.

    PubMed

    Chang, S; Tan, C; Frankel, E N; Barrett, D M

    2000-02-01

    The antioxidant potential of eight clingstone peach cultivars was investigated by determining phenolic compounds and inhibition of low-density lipoprotein (LDL) oxidation. Cultivars low in polyphenol oxidase (PPO) were also selected to minimize enzymatic browning. Inhibition of LDL oxidation varied from 17.0 to 37.1% in peach flesh extract, from 15.2 to 49.8% in whole peach extract, and from 18.2 to 48.1% in peel extract. Total phenols were 432.8-768.1 mg/kg in flesh extract, 483.3-803.0 mg/kg in whole extract, and 910.9-1922.9 mg/kg in peel extract. The correlation coefficient between relative LDL antioxidant activity and concentration of total phenols was 0.76. Peel PPO activity was higher than flesh activity in most cultivars. The lowest PPO and specific activities were found in the Walgant cultivar, followed by Kakamas and 18-8-23. These three cultivars combine the desirable characteristics of strong antioxidant activity, low PPO activity, and lower susceptibility to browning reactions.

  13. High-capacity electric double-layer capacitor with high-density-activated carbon fiber electrodes

    SciTech Connect

    Nakagawa, Hiroyuki; Shudo, Atsushi; Miura, Kouichi

    2000-01-01

    Recently the authors have presented a method to prepare activated carbon fiber with high bulk density (HD-ACF) without using any binders. The possibility of using the HD-ACF as an electrode for electric double-layer capacitors (EDLCs) was examined in this paper. The capacitance of the EDLC with the HD-ACF electrode increased with the increase of bulk density of the HD-ACF, indicating that individual fibers are highly packed without losing their capacitance. The capacitance also increased in proportion to the size of the HD-ACF electrode. The initial discharge current of the EDLC showed little dependency on either the bulk density or the size of the HD-ACF electrode. These results clarified that the HD-ACF electrode is suitable for constructing a high-power EDLC. The initial discharge current was directly proportional to the conductivity of aqueous KCI used as the electrolyte, indicating that the resistance of the electrolyte is much higher than that of the HD-ACF electrode. This result showed that the efficiency of the HD-ACF was well above the efficiency of the electrolyte used in this study and that the improvement of the ionic conductivity of electrolyte is also necessary for developing a high-power EDLC.

  14. Use of prediction methods to estimate true density of active pharmaceutical ingredients.

    PubMed

    Cao, Xiaoping; Leyva, Norma; Anderson, Stephen R; Hancock, Bruno C

    2008-05-01

    True density is a fundamental and important property of active pharmaceutical ingredients (APIs). Using prediction methods to estimate the API true density can be very beneficial in pharmaceutical research and development, especially when experimental measurements cannot be made due to lack of material or sample handling restrictions. In this paper, two empirical prediction methods developed by Girolami and Immirzi and Perini were used to estimate the true density of APIs, and the estimation results were compared with experimentally measured values by helium pycnometry. The Girolami method is simple and can be used for both liquids and solids. For the tested APIs, the Girolami method had a maximum error of -12.7% and an average percent error of -3.0% with a 95% CI of (-3.8, -2.3%). The Immirzi and Perini method is more involved and is mainly used for solid crystals. In general, it gives better predictions than the Girolami method. For the tested APIs, the Immirzi and Perini method had a maximum error of 9.6% and an average percent error of 0.9% with a 95% CI of (0.3, 1.6%). PMID:18242023

  15. Neonatal hemodynamic response to visual cortex activity: high-density near-infrared spectroscopy study

    NASA Astrophysics Data System (ADS)

    Liao, Steve M.; Gregg, Nick M.; White, Brian R.; Zeff, Benjamin W.; Bjerkaas, Katelin A.; Inder, Terrie E.; Culver, Joseph P.

    2010-03-01

    The neurodevelopmental outcome of neonatal intensive care unit (NICU) infants is a major clinical concern with many infants displaying neurobehavioral deficits in childhood. Functional neuroimaging may provide early recognition of neural deficits in high-risk infants. Near-infrared spectroscopy (NIRS) has the advantage of providing functional neuroimaging in infants at the bedside. However, limitations in traditional NIRS have included contamination from superficial vascular dynamics in the scalp. Furthermore, controversy exists over the nature of normal vascular, responses in infants. To address these issues, we extend the use of novel high-density NIRS arrays with multiple source-detector distances and a superficial signal regression technique to infants. Evaluations of healthy term-born infants within the first three days of life are performed without sedation using a visual stimulus. We find that the regression technique significantly improves brain activation signal quality. Furthermore, in six out of eight infants, both oxy- and total hemoglobin increases while deoxyhemoglobin decreases, suggesting that, at term, the neurovascular coupling in the visual cortex is similar to that found in healthy adults. These results demonstrate the feasibility of using high-density NIRS arrays in infants to improve signal quality through superficial signal regression, and provide a foundation for further development of high-density NIRS as a clinical tool.

  16. Regulation of Rac1 activation by the low density lipoprotein receptor-related protein.

    PubMed

    Ma, Zhong; Thomas, Keena S; Webb, Donna J; Moravec, Radim; Salicioni, Ana Maria; Mars, Wendy M; Gonias, Steven L

    2002-12-23

    The low density lipoprotein receptor-related protein (LRP-1) binds and mediates the endocytosis of multiple ligands, transports the urokinase-type plasminogen activator receptor (uPAR) and other membrane proteins into endosomes, and binds intracellular adaptor proteins involved in cell signaling. In this paper, we show that in murine embryonic fibroblasts (MEFs) and L929 cells, LRP-1 functions as a major regulator of Rac1 activation, and that this activity depends on uPAR. LRP-1-deficient MEFs demonstrated increased Rac1 activation compared with LRP-1-expressing MEFs, and this property was reversed by expressing the VLDL receptor, a member of the same gene family as LRP-1, with overlapping ligand-binding specificity. Neutralizing the activity of LRP-1 with receptor-associated protein (RAP) increased Rac1 activation and cell migration in MEFs and L929 cells. The same parameters were unaffected by RAP in uPAR-/- MEFs, prepared from uPAR gene knockout embryos, and in uPAR-deficient LM-TK- cells. Untreated uPAR+/+ MEFs demonstrated substantially increased Rac1 activation compared with uPAR-/- MEFs. In addition to Rac1, LRP-1 suppressed activation of extracellular signal-regulated kinase (ERK) in MEFs; however, it was Rac1 (and not ERK) that was responsible for the effects of LRP-1 on MEF migration. Thus, LRP-1 regulates two signaling proteins in the same cell (Rac1 and ERK), both of which may impact on cell migration. In uPAR-negative cells, LRP-1 neutralization does not affect Rac1 activation, and other mechanisms by which LRP-1 may regulate cell migration are not unmasked.

  17. The condensation and vaporization behavior of H2O:CO ices and implications for interstellar grains and cometary activity

    NASA Technical Reports Server (NTRS)

    Sandford, Scott A.; Allamandola, Louis J.

    1988-01-01

    IR spectroscopy has been used to ascertain several parameters associated with CO, H2O, and H2O:CO ices' physical behavior. Since CO is noted to be capable of condensing into H2O-rich ices at temperatures that are twice as high as those required for condensation in pure CO, CO is able to condense onto H2O-rich ice grains at temperatures of up to 50 K. CO's presence in H2O ice modestly enhances the effective volatility of the H2O. Attention is given to the implications of these results for cometary models generally and the question of cometary formation specifically.

  18. Physical Activity Level of Post-menopausal Women with Low Bone Mineral Density.

    PubMed

    Dallanezi, Glauber; Freire, Beatriz Funayama Alvarenga; Nahás, Eliana Aguiar Petri; Nahás-Neto, Jorge; Corrente, José Eduardo; Mazeto, Gláucia Maria Ferreira da Silva

    2016-05-01

    Introduction Proper physical activity is related to the prevention and the treatment of osteoporosis. Purpose To assess the level of physical activity (PA) in post-menopausal women with low bone mineral density (BMD). Methods This cross-sectional clinical study included 123 post-menopausal women. The inclusion criteria were: age of ≥ 45 years with last menses at least 12 months prior to the initiation of the study, and bone density scan (BDS) values measured over the preceding 12 months. Women with severe osteoarthritis were excluded. Women were allocated into three groups, according to BMD measured by BDS [osteoporosis (OP; 54 women), osteopenia (35 women), and normal bone density (NBD; 35 women)], and compared for general, clinical, and anthropometric data, and for PA level. The latter was assessed using the International Physical Activity Questionnaire (IPAQ), in metabolic equivalent of task (MET) units. Participants were classified as sedentary, active or very active. Quantitative variables were compared using ANOVA followed by Tukey's test. Associations between qualitative variables were tested by Chi-square (χ2) or Fisher's exact test. In order to check for differences among groups and IPAQ domains, a generalized linear model with Gamma distribution was adjusted for values in METs. Results The OP group differed from the NBD group regarding age (61.8 ± 10.1 and 52.9 ± 5.4 years), percentage of participants with self-declared white ethnicity (43.9 and 28.0%), body mass index (BMI - 25.7 ± 5.4 and 30.9 ± 5.1 kg/m(2)), and time since menopause (15.5 ± 7.5 and 5.8 ± 4.5 years). Smoking rates were higher in the OP (55.6%) and NBD groups (33.3%) than in the osteopenia group (11.1%). Within the OP group, the rate of subjects with sedentary lifestyles was higher (42.6%), and time spent sitting was greater (344.3 ± 204.8 METs) than in the groups with osteopenia (20.0% and 300.9 ± 230.6 METs) and NBD (17.7% and 303

  19. Pharmacogenetics of paraoxonase activity: elucidating the role of high-density lipoprotein in disease

    PubMed Central

    Kim, Daniel Seung; Marsillach, Judit; Furlong, Clement E; Jarvik, Gail P

    2014-01-01

    PON1 is a key component of high-density lipoproteins (HDLs) and is at least partially responsible for HDL's antioxidant/atheroprotective properties. PON1 is also associated with numerous human diseases, including cardiovascular disease, Parkinson's disease and cancer. In addition, PON1 metabolizes a broad variety of substrates, including toxic organophosphorous compounds, statin adducts, glucocorticoids, the likely atherogenic l-homocysteine thiolactone and the quorum-sensing factor of Pseudomonas aeruginosa. Numerous cardiovascular and antidiabetic pharmacologic agents, dietary macronutrients, lifestyle factors and antioxidant supplements affect PON1 expression and enzyme activity levels. Owing to the importance of PON1 to HDL function and its individual association with diverse human diseases, pharmacogenomic interactions between PON1 and the various factors that alter its expression and activity may represent an important therapeutic target for future investigation. PMID:24024900

  20. ACTIVE CATHODES FOR SUPER-HIGH POWER DENSITY SOLID OXIDE FUEL CELLS THROUGH SPACE CHARGE EFFECTS

    SciTech Connect

    Anil V. Virkar

    2004-03-08

    This report summarizes the work done during the fifth quarter of the project. Effort was directed in two areas: (1) Further development of the model on the role of connectivity on ionic conductivity of porous bodies, including the role of grain boundaries and space charge region. (2) Fabrication of porous samaria-doped ceria (SDC) and investigation of the effect of thermal treatment on its conductivity. The model developed accounts for transport through three regions: (a) Transport through the bulk of the grain, RI, which includes parallel transport through space charge region. (b) Transport through the space charge region adjacent to the neck (grain boundary), RII. (c) Transport through the structural part of the neck (grain boundary), RIII. The work on the model development involves calculation RI, RII, RIII, and the sum of these three terms, which is the total resistance, as a function of the grain radius ranging between 0.5 and 5 microns and as a function of the relative neck size, described in terms of the angle theta, ranging between 5 and 45{sup o}. Three values of resistivity of the space charge region were chosen; space charge resistivity greater than grain resistivity, equal to grain resistivity, and lower than grain resistivity. Experimental work was conducted on samaria (Sm{sub 2}O{sub 3})-doped ceria (SDC) samples of differing porosity levels, before and after thermal treatment at 1200 C. The conductivity in the annealed samples was lower, consistent with enhanced Debye length. This shows the important role of space charge on ionic transport, and its implications concerning cathode polarization.

  1. A density functional theory model of mechanically activated silyl ester hydrolysis

    SciTech Connect

    Pill, Michael F.; Schmidt, Sebastian W.; Beyer, Martin K.; Clausen-Schaumann, Hauke; Kersch, Alfred

    2014-01-28

    To elucidate the mechanism of the mechanically activated dissociation of chemical bonds between carboxymethylated amylose (CMA) and silane functionalized silicon dioxide, we have investigated the dissociation kinetics of the bonds connecting CMA to silicon oxide surfaces with density functional calculations including the effects of force, solvent polarizability, and pH. We have determined the activation energies, the pre-exponential factors, and the reaction rate constants of candidate reactions. The weakest bond was found to be the silyl ester bond between the silicon and the alkoxy oxygen atom. Under acidic conditions, spontaneous proton addition occurs close to the silyl ester such that neutral reactions become insignificant. Upon proton addition at the most favored position, the activation energy for bond hydrolysis becomes 31 kJ mol{sup −1}, which agrees very well with experimental observation. Heterolytic bond scission in the protonated molecule has a much higher activation energy. The experimentally observed bi-exponential rupture kinetics can be explained by different side groups attached to the silicon atom of the silyl ester. The fact that different side groups lead to different dissociation kinetics provides an opportunity to deliberately modify and tune the kinetic parameters of mechanically activated bond dissociation of silyl esters.

  2. Extracting extensor digitorum communis activation patterns using high-density surface electromyography

    PubMed Central

    Hu, Xiaogang; Suresh, Nina L.; Xue, Cindy; Rymer, William Z.

    2015-01-01

    The extensor digitorum communis muscle plays an important role in hand dexterity during object manipulations. This multi-tendinous muscle is believed to be controlled through separate motoneuron pools, thereby forming different compartments that control individual digits. However, due to the complex anatomical variations across individuals and the flexibility of neural control strategies, the spatial activation patterns of the extensor digitorum communis compartments during individual finger extension have not been fully tracked under different task conditions. The objective of this study was to quantify the global spatial activation patterns of the extensor digitorum communis using high-density (7 × 9) surface electromyogram (EMG) recordings. The muscle activation map (based on the root mean square of the EMG) was constructed when subjects performed individual four finger extensions at the metacarpophalangeal joint, at different effort levels and under different finger constraints (static and dynamic). Our results revealed distinct activation patterns during individual finger extensions, especially between index and middle finger extensions, although the activation between ring and little finger extensions showed strong covariance. The activation map was relatively consistent at different muscle contraction levels and for different finger constraint conditions. We also found that distinct activation patterns were more discernible in the proximal–distal direction than in the radial–ulnar direction. The global spatial activation map utilizing surface grid EMG of the extensor digitorum communis muscle provides information for localizing individual compartments of the extensor muscle during finger extensions. This is of potential value for identifying more selective control input for assistive devices. Such information can also provide a basis for understanding hand impairment in individuals with neural disorders. PMID:26500558

  3. ACTIVE CATHODES FOR SUPER-HIGH POWER DENSITY SOLID OXIDE FUEL CELLS THROUGH SPACE CHARGE EFFECTS

    SciTech Connect

    Anil V. Virkar

    2003-12-12

    This report summarizes the work done during the fourth quarter of the project. Effort was directed in two areas, namely, continued further development of the model on the role of connectivity on ionic conductivity of porous bodies, including the role of grain boundaries and space charge, and its relationship to cathode polarization; and fabrication of samaria-doped ceria porous (SDC). The work on the model development involves calculation of the effect of space charge on transport through porous bodies. Three specific cases have been examined: (1) Space charge resistivity greater than the grain resistivity, (2) Space charge resistivity equal to the grain resistivity, and (3) Space charge resistivity lower than the grain resistivity. The model accounts for transport through three regions: the bulk of the grain, the space charge region, and the structural part of the grain boundary. The effect of neck size has been explicitly incorporated. In future work, the effective resistivity will be incorporated into the effective cathode polarization resistance. The results will then be compared with experiments.

  4. Cholesteryl Ester Hydroperoxides Are Biologically Active Components of Minimally Oxidized Low Density Lipoprotein*S⃞

    PubMed Central

    Harkewicz, Richard; Hartvigsen, Karsten; Almazan, Felicidad; Dennis, Edward A.; Witztum, Joseph L.; Miller, Yury I.

    2008-01-01

    Oxidation of low density lipoprotein (LDL) occurs in vivo and significantly contributes to the development of atherosclerosis. An important mechanism of LDL oxidation in vivo is its modification with 12/15-lipoxygenase (LO). We have developed a model of minimally oxidized LDL (mmLDL) in which native LDL is modified by cells expressing 12/15LO. This mmLDL activates macrophages inducing membrane ruffling and cell spreading, activation of ERK1/2 and Akt signaling, and secretion of proinflammatory cytokines. In this study, we found that many of the biological activities of mmLDL were associated with cholesteryl ester (CE) hydroperoxides and were diminished by ebselen, a reducing agent. Liquid chromatography coupled with mass spectroscopy demonstrated the presence of many mono- and polyoxygenated CE species in mmLDL but not in native LDL. Nonpolar lipid extracts of mmLDL activated macrophages, although to a lesser degree than intact mmLDL. The macrophage responses were also induced by LDL directly modified with immobilized 12/15LO, and the nonpolar lipids extracted from 12/15LO-modified LDL contained a similar set of oxidized CE. Cholesteryl arachidonate modified with 12/15LO also activated macrophages and contained a similar collection of oxidized CE molecules. Remarkably, many of these oxidized CE were found in the extracts of atherosclerotic lesions isolated from hyperlipidemic apoE–/– mice. These results suggest that CE hydroperoxides constitute a class of biologically active components of mmLDL that may be relevant to proinflammatory activation of macrophages in atherosclerotic lesions. PMID:18263582

  5. Colony density and activity times of the ant Camponotus semitestaceus (Hymenoptera: formicidae) in a shrub steppe community

    SciTech Connect

    Gano, K.A.; Rogers, L.E.

    1983-11-01

    Colony densities and above-ground activity periods were determined for Camponotus semitestaceus colonies within a shrub-steppe community. Colony densities (anti-x +/- SD) averaged 0.088 +/- 0.032 per m/sup 2/ and 0.048 +/- 0.028 per m/sup 2/ on two sagebrush-bunchgrass sites an

  6. Whole Grains and Fiber

    MedlinePlus

    ... fiber. Some examples of refined grains are wheat flour, enriched bread and white rice. Most refined grains are enriched , which means that ... grains. Some examples of enriched grains are wheat flour, enriched bread and white rice. Eating whole grains provides important health benefits: Many ...

  7. Fuzzy electron density fragments in macromolecular quantum chemistry, combinatorial quantum chemistry, functional group analysis, and shape-activity relations.

    PubMed

    Mezey, Paul G

    2014-09-16

    Conspectus Just as complete molecules have no boundaries and have "fuzzy" electron density clouds approaching zero density exponentially at large distances from the nearest nucleus, a physically justified choice for electron density fragments exhibits similar behavior. Whereas fuzzy electron densities, just as any fuzzy object, such as a thicker cloud on a foggy day, do not lend themselves to easy visualization, one may partially overcome this by using isocontours. Whereas a faithful representation of the complete fuzzy density would need infinitely many such isocontours, nevertheless, by choosing a selected few, one can still obtain a limited pictorial representation. Clearly, such images are of limited value, and one better relies on more complete mathematical representations, using, for example, density matrices of fuzzy fragment densities. A fuzzy density fragmentation can be obtained in an exactly additive way, using the output from any of the common quantum chemical computational techniques, such as Hartree-Fock, MP2, and various density functional approaches. Such "fuzzy" electron density fragments properly represented have proven to be useful in a rather wide range of applications, for example, (a) using them as additive building blocks leading to efficient linear scaling macromolecular quantum chemistry computational techniques, (b) the study of quantum chemical functional groups, (c) using approximate fuzzy fragment information as allowed by the holographic electron density theorem, (d) the study of correlations between local shape and activity, including through-bond and through-space components of interactions between parts of molecules and relations between local molecular shape and substituent effects, (e) using them as tools of density matrix extrapolation in conformational changes, (f) physically valid averaging and statistical distribution of several local electron densities of common stoichiometry, useful in electron density databank mining, for

  8. Enhanced Sphingomyelinase Activity Contributes to the Apoptotic Capacity of Electronegative Low-Density Lipoprotein.

    PubMed

    Ke, Liang-Yin; Chan, Hua-Chen; Chen, Chih-Chieh; Lu, Jonathan; Marathe, Gopal K; Chu, Chih-Sheng; Chan, Hsiu-Chuan; Wang, Chung-Ya; Tung, Yi-Ching; McIntyre, Thomas M; Yen, Jeng-Hsien; Chen, Chu-Huang

    2016-02-11

    Sphingomyelinase (SMase) catalyzes the degradation of sphingomyelin to ceramide. In patients with metabolic syndrome or diabetes, circulating plasma ceramide levels are significantly higher than in normal individuals. Our data indicate that electronegative low-density lipoprotein (LDL) shows SMase activity, which leads to increased ceramide levels that can produce pro-inflammatory effects and susceptibility to aggregation. According to sequence alignment and protein structure predictions, the putative catalytic site of SMase activity is in the α2 region of apoB-100. To identify specific post-translational modifications of apoB100 near the catalytic region, we performed data-independent, parallel-fragmentation liquid chromatography/mass spectrometry (LC/MS(E)), followed by data analysis with ProteinLynx GlobalServer v2.4. Results showed that the serine of apoB100 in electronegative LDL was highly O-glycosylated, including S(1732), S(1959), S(2378), S(2408), and S(2429). These findings may support the changing of the α-helix/β-pleated sheets ratio in protein structure analysis. Further study is necessary to confirm the activation of SMase activity by electronegative LDL. PMID:26766134

  9. Density-matrix renormalization group algorithm with multi-level active space.

    PubMed

    Ma, Yingjin; Wen, Jing; Ma, Haibo

    2015-07-21

    The density-matrix renormalization group (DMRG) method, which can deal with a large active space composed of tens of orbitals, is nowadays widely used as an efficient addition to traditional complete active space (CAS)-based approaches. In this paper, we present the DMRG algorithm with a multi-level (ML) control of the active space based on chemical intuition-based hierarchical orbital ordering, which is called as ML-DMRG with its self-consistent field (SCF) variant ML-DMRG-SCF. Ground and excited state calculations of H2O, N2, indole, and Cr2 with comparisons to DMRG references using fixed number of kept states (M) illustrate that ML-type DMRG calculations can obtain noticeable efficiency gains. It is also shown that the orbital re-ordering based on hierarchical multiple active subspaces may be beneficial for reducing computational time for not only ML-DMRG calculations but also DMRG ones with fixed M values. PMID:26203012

  10. A Comparison of Bone Mineral Density in Amateur Male Boxers and Active Non-boxers.

    PubMed

    Bolam, K A; Skinner, T L; Sax, A T; Adlard, K N; Taaffe, D R

    2016-08-01

    To examine the site-specific osteogenic effect of upper limb impact-loading activity we compared the forearm and arm bone mineral density (BMD) of male boxers to that of active controls. A cross-sectional study was performed with 30 amateur male boxers (aged 18-44 years) and 32 age-matched, non-boxing, active controls. Participants had their regional and whole body BMD and bone mineral content (BMC) assessed by dual-energy X-ray absorptiometry. Hand grip strength, testosterone, oestradiol, sex hormone-binding globulin, vitamin D, lean and fat mass, and past and current physical activity were also assessed. Forearm and arm BMD were 1.5-2.2% higher in boxers than the control group although this was not statistically significant (p>0.05), with no significant difference for BMC (p>0.05). There were no differences between groups for spine, hip, or whole body BMD or BMC, or for body composition or hormone status. Within the arms, lean mass was associated with BMD and BMC in both boxers and the control group (BMD, r=0.60-0.76, p<0.001; BMC, r=0.67-0.82, p<0.001). There were no significant differences between amateur boxers and the control group for upper limb BMD and BMC. However, muscle mass appears to be particularly important to bone health of the upper limbs. PMID:27203576

  11. Accelerating wavefunction in density-functional-theory embedding by truncating the active basis set.

    PubMed

    Bennie, Simon J; Stella, Martina; Miller, Thomas F; Manby, Frederick R

    2015-07-14

    Methods where an accurate wavefunction is embedded in a density-functional description of the surrounding environment have recently been simplified through the use of a projection operator to ensure orthogonality of orbital subspaces. Projector embedding already offers significant performance gains over conventional post-Hartree-Fock methods by reducing the number of correlated occupied orbitals. However, in our first applications of the method, we used the atomic-orbital basis for the full system, even for the correlated wavefunction calculation in a small, active subsystem. Here, we further develop our method for truncating the atomic-orbital basis to include only functions within or close to the active subsystem. The number of atomic orbitals in a calculation on a fixed active subsystem becomes asymptotically independent of the size of the environment, producing the required O(N(0)) scaling of cost of the calculation in the active subsystem, and accuracy is controlled by a single parameter. The applicability of this approach is demonstrated for the embedded many-body expansion of binding energies of water hexamers and calculation of reaction barriers of SN2 substitution of fluorine by chlorine in α-fluoroalkanes.

  12. Characterization of ichthyocidal activity of Pfiesteria piscicida: dependence on the dinospore cell density.

    PubMed

    Drgon, Tomás; Saito, Keiko; Gillevet, Patrick M; Sikaroodi, Masoumeh; Whitaker, Brent; Krupatkina, Danara N; Argemi, Federico; Vasta, Gerardo R

    2005-01-01

    The ichthyocidal activity of Pfiesteria piscicida dinospores was examined in an aquarium bioassay format by exposing fish to either Pfiesteria-containing environmental sediments or clonal P. piscicida. The presence of Pfiesteria spp. and the complexity of the microbial assemblage in the bioassay were assessed by molecular approaches. Cell-free water from bioassays that yielded significant fish mortality failed to show ichthyocidal activity. Histopathological examination of moribund and dead fish failed to reveal the skin lesions reported elsewhere. Fish larvae within "cages" of variable mesh sizes were killed in those where the pore size exceeded that of Pfiesteria dinospores. In vitro exposure of fish larvae to clonal P. piscicida indicated that fish mortality was directly proportional to the dinospore cell density. Dinospores clustered around the mouth, eyes, and operculi, suggesting that fish health may be affected by their direct interaction with skin, gill epithelia, or mucous surfaces. Molecular fingerprinting revealed the presence of a very diverse microbial community of bacteria, protists, and fungi within bioassay aquaria containing environmental sediments. Some components of the microbial community were identified as potential fish pathogens, preventing the rigorous identification of Pfiesteria spp. as the only cause of fish death. In summary, our results strongly suggest (i) that this aquarium bioassay format, which has been extensively reported in the literature, is unsuitable to accurately assess the ichthyocidal activity of Pfiesteria spp. and (ii) that the ichthyocidal activity of Pfiesteria spp. is mostly due to direct interactions of the zoospores with fish skin and gill epithelia rather than to soluble factors.

  13. Receptor density is key to the alpha2/beta interferon differential activities.

    PubMed

    Moraga, Ignacio; Harari, Daniel; Schreiber, Gideon; Uzé, Gilles; Pellegrini, Sandra

    2009-09-01

    Multiple type I interferons (IFN-alpha/beta) elicit Jak/Stat activation, rapid gene induction, and pleiotropic effects, such as differentiation, antiviral protection, and blocks in proliferation, which are dependent on the IFN subtype and the cellular context. To date, ligand- and receptor-specific molecular determinants underlying IFN-alpha/beta differential activities or potencies have been well characterized. To analyze cellular determinants that impact subtype-specific potency, human fibrosarcoma U5A-derived clones, exhibiting a gradient of IFN sensitivity by virtue of increasing receptor levels, were monitored for Jak/Stat signaling, gene induction, cell cycle lengthening, and apoptosis. In cells with scarce receptors, IFN-beta was more potent than IFN-alpha2 in antiproliferative activity, while the two subtypes were equipotent in all other readouts. Conversely, in cells with abundant receptors, IFN-alpha2 matched or even surpassed IFN-beta in all readouts tested. Our results suggest that the differential activities of the IFN subtypes are dictated not only by the intrinsic ligand/receptor binding kinetics but also by the density of cell surface receptor components.

  14. Antioxidant activities of distiller dried grains with solubles as protein films containing tea extracts and their application in the packaging of pork meat.

    PubMed

    Yang, Hyun-Ju; Lee, Ji-Hyeon; Won, Misun; Song, Kyung Bin

    2016-04-01

    Distiller dried grains with solubles (DDGS) as protein (DP) films were prepared. Additionally, to prepare anti-oxidant films, green tea extract (GTE), oolong tea extract (OTE), and black tea extract (BTE) were incorporated into the DP films. Consequently, the incorporation of the tea extracts did not alter the physical properties of the films much, whereas the antioxidant activities, such as ABTS and DPPH radical scavenging activities were observed. To apply the DP films containing tea extracts to food packaging, pork meat was wrapped with the films and stored at 4 °C for 10 d. During storage, the pork meat wrapped with the DP films containing GTE, OTE, and BTE had less lipid oxidation than did the control. Among the tea extracts, the DP film containing GTE had the greatest antioxidant activity. These results indicate that the DP films containing green tea extracts can be utilized as an anti-oxidative packaging material for pork meat.

  15. Antioxidant activities of distiller dried grains with solubles as protein films containing tea extracts and their application in the packaging of pork meat.

    PubMed

    Yang, Hyun-Ju; Lee, Ji-Hyeon; Won, Misun; Song, Kyung Bin

    2016-04-01

    Distiller dried grains with solubles (DDGS) as protein (DP) films were prepared. Additionally, to prepare anti-oxidant films, green tea extract (GTE), oolong tea extract (OTE), and black tea extract (BTE) were incorporated into the DP films. Consequently, the incorporation of the tea extracts did not alter the physical properties of the films much, whereas the antioxidant activities, such as ABTS and DPPH radical scavenging activities were observed. To apply the DP films containing tea extracts to food packaging, pork meat was wrapped with the films and stored at 4 °C for 10 d. During storage, the pork meat wrapped with the DP films containing GTE, OTE, and BTE had less lipid oxidation than did the control. Among the tea extracts, the DP film containing GTE had the greatest antioxidant activity. These results indicate that the DP films containing green tea extracts can be utilized as an anti-oxidative packaging material for pork meat. PMID:26593480

  16. High mature grain phytase activity in the Triticeae has evolved by duplication followed by neofunctionalization of the purple acid phosphatase phytase (PAPhy) gene

    PubMed Central

    Brinch-Pedersen, Henrik

    2013-01-01

    The phytase activity in food and feedstuffs is an important nutritional parameter. Members of the Triticeae tribe accumulate purple acid phosphatase phytases (PAPhy) during grain filling. This accumulation elevates mature grain phytase activities (MGPA) up to levels between ~650 FTU/kg for barley and 6000 FTU/kg for rye. This is notably more than other cereals. For instance, rice, maize, and oat have MGPAs below 100 FTU/kg. The cloning and characterization of the PAPhy gene complement from wheat, barley, rye, einkorn, and Aegilops tauschii is reported here. The Triticeae PAPhy genes generally consist of a set of paralogues, PAPhy_a and PAPhy_b, and have been mapped to Triticeae chromosomes 5 and 3, respectively. The promoters share a conserved core but the PAPhy_a promoter have acquired a novel cis-acting regulatory element for expression during grain filling while the PAPhy_b promoter has maintained the archaic function and drives expression during germination. Brachypodium is the only sequenced Poaceae sharing the PAPhy duplication. As for the Triticeae, the duplication is reflected in a high MGPA of ~4200 FTU/kg in Brachypodium. The sequence conservation of the paralogous loci on Brachypodium chromosomes 1 and 2 does not extend beyond the PAPhy gene. The results indicate that a single-gene segmental duplication may have enabled the evolution of high MGPA by creating functional redundancy of the parent PAPhy gene. This implies that similar MGPA levels may be out of reach in breeding programs for some Poaceae, e.g. maize and rice, whereas Triticeae breeders should focus on PAPhy_a. PMID:23918958

  17. Electronic properties of silicon grain boundaries

    SciTech Connect

    Pike, G.E.; Seager, C.H.

    1980-01-01

    Polycrystalline silicon is a clean and relatively simple prototype of electronic ceramics. The theory of the electrostatic barriers which form at silicon grain boundaries will be discussed. The use of experimental conductance and capacitance measurements to obtain the barrier height and energy density of grain boundary states will be illustrated.

  18. JNK1 stress signaling is hyper-activated in high breast density and the tumor stroma

    PubMed Central

    Lisanti, Michael P; Tsirigos, Aristotelis; Pavlides, Stephanos; Reeves, Kimberley Jayne; Peiris-Pagès, Maria; Chadwick, Amy L; Sanchez-Alvarez, Rosa; Lamb, Rebecca; Howell, Anthony; Martinez-Outschoorn, Ubaldo E; Sotgia, Federica

    2014-01-01

    Mammography is an important screening modality for the early detection of DCIS and breast cancer lesions. More specifically, high mammographic density is associated with an increased risk of breast cancer. However, the biological processes underlying this phenomenon remain largely unknown. Here, we re-interrogated genome-wide transcriptional profiling data obtained from low-density (LD) mammary fibroblasts (n = 6 patients) and high-density (HD) mammary fibroblasts (n = 7 patients) derived from a series of 13 female patients. We used these raw data to generate a “breast density” gene signature consisting of >1250 transcripts that were significantly increased in HD fibroblasts, relative to LD fibroblasts. We then focused on the genes that were increased by ≥ 1.5-fold (P < 0.05) and performed gene set enrichment analysis (GSEA), using the molecular signatures database (MSigDB). Our results indicate that HD fibroblasts show the upregulation and/or hyper-activation of several key cellular processes, including the stress response, inflammation, stemness, and signal transduction. The transcriptional profiles of HD fibroblasts also showed striking similarities to human tumors, including head and neck, liver, thyroid, lung, and breast cancers. This may reflect functional similarities between cancer-associated fibroblasts (CAFs) and HD fibroblasts. This is consistent with the idea that the presence of HD fibroblasts may be a hallmark of a pre-cancerous phenotype. In these biological processes, GSEA predicts that several key signaling pathways may be involved, including JNK1, iNOS, Rho GTPase(s), FGF-R, EGF-R, and PDGF-R-mediated signal transduction, thereby creating a pro-inflammatory, pro-proliferative, cytokine, and chemokine-rich microenvironment. HD fibroblasts also showed significant overlap with gene profiles derived from smooth muscle cells under stress (JNK1) and activated/infected macrophages (iNOS). Thus, HD fibroblasts may behave like activated

  19. Modeling the development of biofilm density including active bacteria, inert biomass, and extracellular polymeric substances.

    PubMed

    Laspidou, Chrysi S; Rittmann, Bruce E

    2004-01-01

    We present the unified multi-component cellular automaton (UMCCA) model, which predicts quantitatively the development of the biofilm's composite density for three biofilm components: active bacteria, inert or dead biomass, and extracellular polymeric substances. The model also describes the concentrations of three soluble organic components (soluble substrate and two types of soluble microbial products) and oxygen. The UMCCA model is a hybrid discrete-differential mathematical model and introduces the novel feature of biofilm consolidation. Our hypothesis is that the fluid over the biofilm creates pressures and vibrations that cause the biofilm to consolidate, or pack itself to a higher density over time. Each biofilm compartment in the model output consolidates to a different degree that depends on the age of its biomass. The UMCCA model also adds a cellular automaton algorithm that identifies the path of least resistance and directly moves excess biomass along that path, thereby ensuring that the excess biomass is distributed efficiently. A companion paper illustrates the trends that the UMCCA model is able to represent and shows a comparison with experimental results. PMID:15276752

  20. Bone geometry, density, and strength indices of the distal radius reflect loading via childhood gymnastic activity.

    PubMed

    Dowthwaite, Jodi N; Flowers, Portia P E; Spadaro, Joseph A; Scerpella, Tamara A

    2007-01-01

    The distal radius bears unique forces during gymnastic activity. Its relatively simple anatomy, minimal soft tissue envelope, and varied composition make the distal radius ideal for evaluating the effects of loading on bone properties. For 56 premenarcheal gymnasts and nongymnasts, ultradistal and 1/3 distal radius DXA scans measured bone mineral content (BMC), areal bone mineral density, and projected area. Simplified geometric models were used to generate bone mineral apparent density (BMAD), geometric indices, strength indices, and fall strength ratios. Ratios of regional BMC vs total body fat-free mass (FFM) were calculated. Separate Tanner I and II analyses of covariance adjusted bone parameters for age and height. Ratios were compared using maturity-matched analyses of variance. At the 1/3 region, periosteal width, BMC, cortical cross-sectional area, and section modulus were greater in gymnasts than nongymnasts (p<0.05); 1/3 BMAD means were equivalent. Ultradistal BMAD, BMC, and index for structural strength in axial compression were higher in gymnasts than nongymnasts; ultradistal periosteal width was only larger in Tanner I gymnasts. Fall strength ratios and BMC/FFM ratios were greater in gymnasts (p<0.05). Geometric and volumetric responses to mechanical loading are site specific during late childhood and early adolescence.

  1. Glutathione transferase activity and expression patterns during grain filling in flag leaves of wheat genotypes differing in drought tolerance: Response to water deficit.

    PubMed

    Gallé, Agnes; Csiszár, Jolán; Secenji, Maria; Guóth, Adrienn; Cseuz, László; Tari, Irma; Györgyey, János; Erdei, László

    2009-11-15

    Total glutathione S-transferase (GST, EC 2.5.1.18) and glutathione peroxidase (GPOX) activity were measured spectrophotometrically in Triticum aestivum cv. MV Emese and cv. Plainsman (drought tolerant) and cv. GK Elet and Cappelle Desprez (drought-sensitive) flag leaves under control and drought stress conditions during the grain-filling period, in order to reveal possible roles of different GST classes in the senescence of flag leaves. Six wheat GSTs, members of 3 GST classes, were selected and their regulation by drought and senescence was investigated. High GPOX activity (EC 1.11.1.9) was observed in well-watered controls of the drought-tolerant Plainsman cultivar. At the same time, TaGSTU1B and TaGSTF6 sequences, investigated by real-time PCR, showed high-expression levels that increased with time, indicating that the gene products of these genes may play important roles in monocarpic senescence of wheat. Expression of these genes was also induced by drought stress in all of the four investigated cultivars, but extremely high transcript amounts were detected in cv. Plainsman. Our data indicate genotypic variations of wheat GSTs. Expression levels and early induction of two senescence-associated GSTs under drought during grain filling in flag leaves correlated with high yield stability.

  2. Permeation of oxygen through high purity, large grain silver

    NASA Technical Reports Server (NTRS)

    Outlaw, R. A.; Peregoy, W. K.; Hoflund, Gar B.

    1987-01-01

    The permeation of high purity, large grain Ag membranes by oxygen has been studied over the temperature range 400 to 800 C. The permeability was found to be quite linear and repeatable, but the magnitude was 3.2 times smaller than that determined by past research. Since previous investigators studied substantially less pure Ag and conducted experiments within much poorer vacuum environments (which indicates that their grain boundary density was much greater), the data presented here suggest oxygen transport through the membrane is primarily by grain boundary diffusion. The diffusivity measurements were found to exhibit two distinct linear regions, one above and one below a critical temperature of 630 C. The high-temperature data have an activation energy (11.1 kcal/mole) similar to that reported by others, but the low-temperature data have a higher activation energy (15.3 kcal/mole), which can be explained by impurity trapping in the grain boundaries. Vacuum desorption of the oxygen-saturated Ag was found to occur at a threshold of 630 C, which is consistent with the onset of increased mobility within the grain boundaries.

  3. Critical current density, irreversibility line, and flux creep activation energy in silver-sheathed Bi[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub x] superconducting tapes

    SciTech Connect

    Shi, D.; Wang, Z.; Sengupta, S.; Smith, M. ); Goodrich, L.F. , Boulder, CO . Electromagnetic Technology Div.); Dou, S.X.; Liu, H.K.; Guo, Y.C. . School of Materials and Engineering)

    1992-08-01

    Transport data, magnetic hysteresis and flux creep activation energy experimental results are presented for silver-sheathed high-[Tc] Bi[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub x] superconducting tapes. The 110 K superconducting phase was formed by lead doping in a Bi-Sr-Ca-Cu-0 system. The transport critical current density was measured at 4.0 K to be 0.7 [times] 10[sup 5] A/cm[sup 2] (the corresponding critical current is 74 A) at zero field and 1.6 [times] 10[sup 4] A/cm[sup 2] at 12 T for H[parallel]ab. Excellent grain alignment in the a-b plane was achieved by a short-melting method, which considerably improved the critical current density and irreversibility line. Flux creep activation energy as a function of current is obtained based on the magnetic relaxation measurements.

  4. Critical current density, irreversibility line, and flux creep activation energy in silver-sheathed Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconducting tapes

    SciTech Connect

    Shi, D.; Wang, Z.; Sengupta, S.; Smith, M.; Goodrich, L.F.; Dou, S.X.; Liu, H.K.; Guo, Y.C.

    1992-08-01

    Transport data, magnetic hysteresis and flux creep activation energy experimental results are presented for silver-sheathed high-{Tc} Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconducting tapes. The 110 K superconducting phase was formed by lead doping in a Bi-Sr-Ca-Cu-0 system. The transport critical current density was measured at 4.0 K to be 0.7 {times} 10{sup 5} A/cm{sup 2} (the corresponding critical current is 74 A) at zero field and 1.6 {times} 10{sup 4} A/cm{sup 2} at 12 T for H{parallel}ab. Excellent grain alignment in the a-b plane was achieved by a short-melting method, which considerably improved the critical current density and irreversibility line. Flux creep activation energy as a function of current is obtained based on the magnetic relaxation measurements.

  5. Density-matrix renormalization-group study of current and activity fluctuations near nonequilibrium phase transitions.

    PubMed

    Gorissen, Mieke; Hooyberghs, Jef; Vanderzande, Carlo

    2009-02-01

    Cumulants of a fluctuating current can be obtained from a free-energy-like generating function, which for Markov processes equals the largest eigenvalue of a generalized generator. We determine this eigenvalue with the density-matrix renormalization group for stochastic systems. We calculate the variance of the current in the different phases, and at the phase transitions, of the totally asymmetric exclusion process. Our results can be described in the terms of a scaling ansatz that involves the dynamical exponent z . We also calculate the generating function of the dynamical activity (total number of configuration changes) near the absorbing-state transition of the contact process. Its scaling properties can be expressed in terms of known critical exponents. PMID:19391693

  6. High-density EMG E-textile systems for the control of active prostheses.

    PubMed

    Farina, Dario; Lorrain, Thomas; Negro, Francesco; Jiang, Ning

    2010-01-01

    Myoelectric control of active prostheses requires electrode systems that are easy to apply for daily repositioning of the electrodes by the user. In this study we propose the use of Smart Fabric and Interactive Textile (SFIT) systems as an alternative solution for recording high-density EMG signals for myoelectric control. A sleeve covering the upper and lower arm, which contains 100 electrodes arranged in four grids of 5 × 5 electrodes, was used to record EMG signals in 3 subjects during the execution of 9 tasks of the wrist and hand. The signals were analyzed by extracting wavelet coefficients which were classified with linear discriminant analysis. The average classification accuracy for the nine tasks was 89.1 ± 1.9 %. These results show that SFIT systems can be used as an effective way for muscle-machine interfacing. PMID:21096838

  7. Density functional theory study of C₂F₅I synthesis over activated carbon catalyst.

    PubMed

    Hu, Yingjie; Xue, Mengwei; Yang, Guangchen; Pan, Renming

    2015-09-01

    Quantum chemistry calculations based on the density functional theory (DFT) are carried out to investigate the reaction mechanism of C2F5I synthesis catalyzed by activated carbon. The possible adsorption configurations of fluorocarbon intermediates are analyzed carefully. Also, the related transition states and reaction pathway are analyzed. According to calculation, firstly, the dehydrofluorination of C2HF5, as the rate-determining step, is catalyzed by the carboxyl acid groups. Secondly, the tetrafluoroethylidene radicals disproportionate on graphite (001) surface instead of rearrangement or dimerization. Next, the fluorine abstractions between fluorocarbon intermediates over graphite (001) surfaces proceed successfully. Finally, the desorbed pentafluoroethyl abstracts iodine atom from molecular iodine spontaneously to afford C2F5I. In adition, our calculations reveal that the carbon deposit in experiment is caused by the fluorine abstraction from fluoroethinyl. The suggested mechanism corresponds with our calculations and available experiments. PMID:26276012

  8. Enhanced photocurrent density in graphene/Si based solar cell (GSSC) by optimizing active layer thickness

    SciTech Connect

    Rosikhin, Ahmad Hidayat, Aulia Fikri; Syuhada, Ibnu; Winata, Toto

    2015-12-29

    Thickness dependent photocurrent density in active layer of graphene/Si based solar cell has been investigated via analytical – simulation study. This report is a preliminary comparison of experimental and analytical investigation of graphene/Si based solar cell. Graphene sheet was interfaced with Si thin film forming heterojunction solar cell that was treated as a device model for photocurrent generator. Such current can be enhanced by optimizing active layer thickness and involving metal oxide as supporting layer to shift photons absorption. In this case there are two type of devices model with and without TiO{sub 2} in which the silicon thickness varied at 20 – 100 nm. All of them have examined and also compared with each other to obtain an optimum value. From this calculation it found that generated currents almost linear with thickness but there are saturated conditions that no more enhancements will be achieved. Furthermore TiO{sub 2} layer is effectively increases photon absorption but reducing device stability, maximum current is fluctuates enough. This may caused by the disturbance of excitons diffusion and resistivity inside each layer. Finally by controlling active layer thickness, it is quite useful to estimate optimization in order to develop the next solar cell devices.

  9. Density Functional Theory Calculations of Activation Energies for Carrier Capture by Defects in Semiconductors

    NASA Astrophysics Data System (ADS)

    Modine, N. A.; Wright, A. F.; Lee, S. R.

    The rate of defect-induced carrier recombination is determined by both defect levels and carrier capture cross-sections. Density functional theory (DFT) has been widely and successfully used to predict defect levels, but only recently has work begun to focus on using DFT to determine carrier capture cross-sections. Lang and Henry developed the theory of carrier-capture by multiphonon emission in the 1970s and showed that carrier-capture cross-sections differ between defects primarily due to differences in their carrier capture activation energies. We present an approach to using DFT to calculate carrier capture activation energies that does not depend on an assumed configuration coordinate and that fully accounts for anharmonic effects, which can substantially modify carrier activation energies. We demonstrate our approach for intrinisic defects in GaAs and GaN and discuss how our results depend on the choice of exchange-correlation functional and the treatment of spin polarization. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  10. History of Presolar Grains

    NASA Technical Reports Server (NTRS)

    Bernatowicz, Thomas J.

    2005-01-01

    Papers on the History of Presolar Grains. This has been a very productive period in which much of the laboratory work conducted in the previous year and during this funding cycle were brought to completion. In the last year we have published or submitted for peer review 4 research papers, 4 review papers, and 11 abstracts in research areas supported under this grant. Brief synopses of the results of the research papers are presented, followed by short summaries of the topics discussed in the review papers. Several areas of research are of course being actively pursued, and the appended list of abstracts gives citations to this ongoing work. In a paper submitted to the Astrophysical Journal, the results of an investigation into the physical conditions in the mass outflows of asymptotic giant branch (AGB) carbon stars that are required for the formation of micron-sized presolar graphite grains, with and without previously formed internal crystals of titanium carbide (TIC) are reported.

  11. Density Functional Theory Study of Oxygen Reduction Activity on Ultrathin Platinum Nanotubes

    SciTech Connect

    Matanovic, Ivana; Kent, Paul; Garzon, Fernando; Henson, Neil J.

    2012-07-13

    The structure, stability, and catalytic activity of a number of single- and double-wall platinum (n,m) nanotubes ranging in diameter from 0.3 to 2.0 nm were studied using plane-wave based density functional theory in the gas phase and water environment. The change in the catalytic activity toward the oxygen reduction reaction (ORR) with the size and chirality of the nanotube was studied by calculating equilibrium adsorption potentials for ORR intermediates and by constructing free energy diagrams in the ORR dissociative mechanism network. In addition, the stability of the platinum nanotubes is investigated in terms of electrochemical dissolution potentials and by determining the most stable state of the material as a function of pH and potential, as represented in Pourbaix diagrams. Our results show that the catalytic activity and the stability toward electrochemical dissolution depend greatly on the diameter and chirality of the nanotube. On the basis of the estimated overpotentials for ORR, we conclude that smaller, approximately 0.5 nm in diameter single-wall platinum nanotubes consistently show a huge, up to 400 mV larger overpotential than platinum, indicating very poor catalytic activity toward ORR. This is the result of substantial structural changes induced by the adsorption of any chemical species on these tubes. Single-wall n = m platinum nanotubes with a diameter larger than 1 nm have smaller ORR overpotentials than bulk platinum for up to 180 mV and thus show improved catalytic activity relative to bulk. We also predict that these nanotubes can endure the highest cell potentials but dissolution potentials are still for 110 mV lower than for the bulk, indicating a possible corrosion problem.

  12. Melting in migmatites associated with sub-grain boundaries in quartz

    NASA Astrophysics Data System (ADS)

    Levine, J.; Mosher, S.

    2010-12-01

    Migmatites from three diverse locations and rock types contain pseudomorphs of melt along sub-grain and grain boundaries, particularly in quartz. This relationship suggests melting preferentially occurs in more strained areas of a crystal lattice, consistent with observations from metallurgy and material science. In metals, ceramics and colloids, it has been demonstrated that melting preferentially occurs on grain boundaries, areas of high dislocation density, and that melting begins in areas that are more highly strained. Molecular dynamics simulations and experiments on colloids show that melting will also occur along sub-grain boundaries if there are no true grain boundaries present. A process known as SIMA (strain-induced melt activation) has been used on Al alloys to create a spherical grain shape, utilizing the fact that melt will preferentially form in high-strain areas, including both grain and sub-grain boundaries. In migmatites, previous work indicates that melt travels along grain boundaries as well as fractures within grains. Experimental work and identification of remnant blebs or pseudomorphs of melt along grain boundaries in natural rocks provides evidence for such transport. Our study of deformed rocks from three areas provides new evidence for melting as well as transport along sub-grain boundaries, particularly in quartz. Granitic gneiss samples from the Llano Uplift, central Texas, are from small-scale shear zones and surrounding country rock. The quartz/K-feldspar grain boundaries commonly have cuspate/serrate edges that are associated with sub-grain boundaries in quartz, and blebs of K-feldspar are found along sub-grain boundaries within quartz grains. The K-feldspar most likely represents pseudomorphs of melt that have migrated into and melted the quartz grain along quartz sub-grain boundaries, creating space for the crystallizing melt. Metapelites from the Wet Mountains of south-central Colorado have undergone partial melting via biotite

  13. ACTIVE CATHODES FOR SUPER-HIGH POWER DENSITY SOLID OXIDE FUEL CELLS THROUGH SPACE CHARGE EFFECTS

    SciTech Connect

    Anil V. Virkar

    2003-11-03

    This report summarizes the work done during the third quarter of the project. Effort was directed in two areas: (1) Further development of the model on the role of connectivity on ionic conductivity of porous bodies, including the role of grain boundaries, and its relationship to cathode polarization. Included indirectly through the grain boundary effect is the effect of space charge. (2) Synthesis of LSC + SDC composite cathode powders by combustion synthesis. (3) Fabrication and testing of anode-supported single cells made using synthesized LSC + ScDC composite cathodes.

  14. Affects of mining activities on Cd pollution to the paddy soils and rice grain in Hunan province, Central South China.

    PubMed

    Du, Yan; Hu, Xue-Feng; Wu, Xiao-Hong; Shu, Ying; Jiang, Ying; Yan, Xiao-Juan

    2013-12-01

    Located in Central South China, Hunan province is rich in mineral resources. To study the influence of mining on Cd pollution to local agricultural eco-system, the paddy soils and rice grain of Y county in northern Hunan province were intensively monitored. The results were as follows: (1) Total Cd (T-Cd) content in the soils of the county ranges from 0.13 to 6.02 mg kg(-1), with a mean of 0.64 mg kg(-1), of which 57.5% exceed the allowable limit specified by the China Soil Environmental Quality Standards. T-Cd in the soils varies largely, with the coefficient of variation reaching 146.4%. The spatial distribution of T-Cd in the soils quite matches with that of mining and industries. The content of HCl-extractable Cd (HCl-Cd) in the soils ranges from 0.02 to 2.17 mg kg(-1), with a mean of 0.24 mg kg(-1). A significant positive correlation exists between T-Cd and HCl-Cd in the soils (r = 0.770, ρ < 0.01). (2) Cd content in the rice produced in Y county ranges from 0.01 to 2.77 mg kg(-1), with a mean of 0.46 mg kg(-1). The rate of rice with Cd exceeding the allowable limit specified by the Chinese Grain Security Standards reaches 59.6%; that with Cd exceeding 1 mg kg(-1), called as "Cd rice," reaches 11.1%. (3) Cd content in the rice of Y county is positively significantly correlated with HCl-Cd (r = 0.177, ρ < 0.05) but not significantly with T-Cd in the soils (r = 0.091, ρ > 0.05), which suggests that the amount of Cd accumulating in the rice is more affected by its availability in the soils, rather than the total content. (4) The dietary intake of Cd via rice consumption in Y county is estimated to be 179.9 μg day(-1) person(-1) on average, which is far beyond the allowable limit specified by FAO/WHO and the target hazard quotients of Cd much higher than 1, suggesting the high risk on human health from Cd exposure.

  15. Transforming a Traditional Hands-On Activity into an Enquiry Activity to Foster More In-Depth Understanding of the Concept of Density

    ERIC Educational Resources Information Center

    Lee, Yeung Chung; Kwok, Ping Wai

    2010-01-01

    Traditional methods used to teach the concept of density that employ solid objects of different masses and volumes can be supplemented by enquiry activities in which students vary the mass-to-volume ratio of the same object to test ideas about density and flotation. A simple substance, Blu-Tack, is an ideal material to use in this case. The…

  16. The independent prospective associations of activity intensity and dietary energy density with adiposity in young adolescents.

    PubMed

    van Sluijs, Esther M F; Sharp, Stephen J; Ambrosini, Gina L; Cassidy, Aedin; Griffin, Simon J; Ekelund, Ulf

    2016-03-14

    There is limited evidence on the prospective association of time spent in activity intensity (sedentary (SED), moderate (MPA) or vigorous (VPA) physical activity) and dietary intake with adiposity indicators in young people. This study aimed to assess associations between (1) baseline objectively measured activity intensity, dietary energy density (DED) and 4-year change in adiposity and (2) 4-year change in activity intensity/DED and adiposity at follow-up. We conducted cohort analyses including 367 participants (10 years at baseline, 14 years at follow-up) with valid data for objectively measured activity (Actigraph), DED (4-d food diary), anthropometry (waist circumference (WC), %body fat (%BF), fat mass index (FMI), weight status) and covariates. Linear and logistic regression models were fit, including adjustment for DED and moderate-to-vigorous physical activity. Results showed that baseline DED was associated with change in WC (β for 1kJ/g difference: 0·71; 95% CI 0·26, 1·17), particularly in boys (1·26; 95% CI 0·41, 2·16 v. girls: 0·26; 95% CI -0·34, 0·87), but not with %BF, FMI or weight status. In contrast, baseline SED, MPA or VPA were not associated with any of the outcomes. Change in DED was negatively associated with FMI (β for 1kJ/g increase: -0·86; 95% CI -1·59, -0·12) and %BF (-0·86; 95% CI -1·25, -0·11) but not WC (-0·27; 95% CI -1·02, 0·48). Change in SED, MPA and VPA did not predict adiposity at follow-up. In conclusion, activity intensity was not prospectively associated with adiposity, whereas the directions of associations with DED were inconsistent. To inform public health efforts, future studies should continue to analyse longitudinal data to further understand the independent role of different energy-balance behaviours in changes in adiposity in early adolescence. PMID:26758859

  17. Bone mineral density and body composition in a myelomeningocele children population: effects of walking ability and sport activity.

    PubMed

    Ausili, E; Focarelli, B; Tabacco, F; Fortunelli, G; Caradonna, P; Massimi, L; Sigismondi, M; Salvaggio, E; Rendeli, C

    2008-01-01

    Myelomeningocele causes serious locomotor disability, osteoporosis and pathologic fractures. The aim of this study was to investigate the relationship between body composition, bone mineral density, walking ability and sport activity in myelomeningocele children. 60 patients aged between 5 and 14 yrs with myelomeningocele (22 ambulatory and 38 non-ambulatory), were studied. Fat mass and fat-free-mass were calculated by anthropometry. The bone mineral density at lumbar and femoral neck were evaluated. Bone mineral density at the lumbar and femoral neck was lower than in the normal population. In the non-ambulaty group, bone mineral density was approximately 1 SD lower than in the ambulatory one (p < 0.01). Fat mass was greater than expected but without significantly differences between walking group (mean 26%) and wheel-chair users (25%). Patients practised sport activity had a better bone mineral density and body fat compared with other patients with the same disability. Patients with myelomeningocele have decreased bone mineral density and are at higher risk of pathologic bone fractures. All subjects showed an excess of fat as percentage of body weight and are shorter than normal children. The measurement of bone mineral density may help to identify those patients at greatest risk of suffering of multiple fractures. Walk ability and sport activity, associated with the development of muscle mass, are important factors in promoting bone and body growth, to reduce the risk of obesity and of pathological fractures. PMID:19146196

  18. A new active Li-Mn-O compound for high energy density Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Freire, M.; Kosova, N. V.; Jordy, C.; Chateigner, D.; Lebedev, O. I.; Maignan, A.; Pralong, V.

    2016-02-01

    The search for new materials that could improve the energy density of Li-ion batteries is one of today’s most challenging issues. Many families of transition metal oxides as well as transition metal polyanionic frameworks have been proposed during the past twenty years. Among them, manganese oxides, such as the LiMn2O4 spinel or the overlithiated oxide Li[Li1/3Mn2/3]O2, have been intensively studied owing to the low toxicity of manganese-based materials and the high redox potential of the Mn3+/Mn4+ couple. In this work, we report on a new electrochemically active compound with the `Li4Mn2O5’ composition, prepared by direct mechanochemical synthesis at room temperature. This rock-salt-type nanostructured material shows a discharge capacity of 355 mAh g-1, which is the highest yet reported among the known lithium manganese oxide electrode materials. According to the magnetic measurements, this exceptional capacity results from the electrochemical activity of the Mn3+/Mn4+ and O2-/O- redox couples, and, importantly, of the Mn4+/Mn5+ couple also.

  19. Fmrp Interacts with Adar and Regulates RNA Editing, Synaptic Density and Locomotor Activity in Zebrafish

    PubMed Central

    Porath, Hagit T.; Barak, Michal; Pinto, Yishay; Wachtel, Chaim; Zilberberg, Alona; Lerer-Goldshtein, Tali; Efroni, Sol; Levanon, Erez Y.; Appelbaum, Lior

    2015-01-01

    Fragile X syndrome (FXS) is the most frequent inherited form of mental retardation. The cause for this X-linked disorder is the silencing of the fragile X mental retardation 1 (fmr1) gene and the absence of the fragile X mental retardation protein (Fmrp). The RNA-binding protein Fmrp represses protein translation, particularly in synapses. In Drosophila, Fmrp interacts with the adenosine deaminase acting on RNA (Adar) enzymes. Adar enzymes convert adenosine to inosine (A-to-I) and modify the sequence of RNA transcripts. Utilizing the fmr1 zebrafish mutant (fmr1-/-), we studied Fmrp-dependent neuronal circuit formation, behavior, and Adar-mediated RNA editing. By combining behavior analyses and live imaging of single axons and synapses, we showed hyperlocomotor activity, as well as increased axonal branching and synaptic density, in fmr1-/- larvae. We identified thousands of clustered RNA editing sites in the zebrafish transcriptome and showed that Fmrp biochemically interacts with the Adar2a protein. The expression levels of the adar genes and Adar2 protein increased in fmr1-/- zebrafish. Microfluidic-based multiplex PCR coupled with deep sequencing showed a mild increase in A-to-I RNA editing levels in evolutionarily conserved neuronal and synaptic Adar-targets in fmr1-/- larvae. These findings suggest that loss of Fmrp results in increased Adar-mediated RNA editing activity on target-specific RNAs, which, in turn, might alter neuronal circuit formation and behavior in FXS. PMID:26637167

  20. A new active Li-Mn-O compound for high energy density Li-ion batteries.

    PubMed

    Freire, M; Kosova, N V; Jordy, C; Chateigner, D; Lebedev, O I; Maignan, A; Pralong, V

    2016-02-01

    The search for new materials that could improve the energy density of Li-ion batteries is one of today's most challenging issues. Many families of transition metal oxides as well as transition metal polyanionic frameworks have been proposed during the past twenty years. Among them, manganese oxides, such as the LiMn2O4 spinel or the overlithiated oxide Li[Li1/3Mn2/3]O2, have been intensively studied owing to the low toxicity of manganese-based materials and the high redox potential of the Mn(3+)/Mn(4+) couple. In this work, we report on a new electrochemically active compound with the 'Li4Mn2O5' composition, prepared by direct mechanochemical synthesis at room temperature. This rock-salt-type nanostructured material shows a discharge capacity of 355 mAh g(-1), which is the highest yet reported among the known lithium manganese oxide electrode materials. According to the magnetic measurements, this exceptional capacity results from the electrochemical activity of the Mn(3+)/Mn(4+) and O(2-)/O(-) redox couples, and, importantly, of the Mn(4+)/Mn(5+) couple also.

  1. Muscle mitochondrial density after exhaustive exercise in dogs - Prolonged restricted activity and retraining

    NASA Technical Reports Server (NTRS)

    Nazar, K.; Greenleaf, J. E.; Philpott, D.; Pohoska, E.; Olszewska, K.; Kaciuba-Uscilko, H.

    1993-01-01

    The effect of exhaustive treadmill exercise on mitochondrial density (MD) and ultrastructural changes in quadriceps femoris muscle was studied in 7 normal, healthy, male mongrel dogs before and after restricted activity (RA) and following a subsequent 2-month exercise retraining period. Mean time to exhaustion in the 2-month group decreased from 177 +/- 11 min before to 90 +/- 16 min after RA; retraining increased tolerance to 219 +/- 36 min above the pre-RA and 143 percent above the post-RA time. Post-RA exhaustion time in the 5-months group was 25 and 45 min. Muscle samples taken after RA showed abnormalities indicative of degeneration, which were reversed by retraining. Resting MD decreased from a control level of 27.8 percent to 14.7 percent and 16.3 percent, and was restored to 27.1 percent after retraining. Exhaustive exercise caused an increase in MD under control conditions and after RA, but not following retraining. Disruption of mitochondria after exercise was evident after 5-month confinement. Factors causing mitochondrial changes and eventually their disruption during exercise after restricted activity are not related as much to the state of fatigue as to the pre-exercise quality of the muscle modified by disease or training.

  2. Tobacco Control: Visualisation of Research Activity Using Density-Equalizing Mapping and Scientometric Benchmarking Procedures

    PubMed Central

    Kusma, Bianca; Scutaru, Cristian; Quarcoo, David; Welte, Tobias; Fischer, Tanja C.; Groneberg-Kloft, Beatrix

    2009-01-01

    Background: Tobacco smoking continues to be a major preventable cause of death and disease and therefore tobacco control research is extremely important. However, research in this area is often hampered by a lack in funding and there is a need for scientometric techniques to display research efforts. Methods: The present study combines classical bibliometric tools with novel scientometric and visualizing techniques in order to analyse and categorise research in the field of tobacco control. Results: All studies related to tobacco control and listed in the ISI database since 1900 were identified by the use of defined search terms. Using bibliometric approaches, a continuous increase in qualitative markers such as collaboration numbers or citations were found for tobacco control research. The combination with density equalizing mapping revealed a distinct global pattern of research productivity and citation activity. Radar chart techniques were used to visualize bi- and multilateral research cooperation and institutional cooperation. Conclusions: The present study supplies a first scientometric approach that visualises research activity in the field of tobacco control. It provides data that can be used for funding policy and the identification of research clusters. PMID:19578464

  3. Bone mineral density of 704 amateur sportsmen involved in different physical activities.

    PubMed

    Morel, J; Combe, B; Francisco, J; Bernard, J

    2001-01-01

    The aim of the study was to analyze the relation between sports and bone mass. Seven hundred and four men with no history of chronic disease were questioned on their adolescent and adult sporting activities. Their total body (TB) and regional (head, spine, arms and legs) bone mineral density (BMD) were measured by dual-energy X-ray absorptiometry. BMD measurements and ratios of regional BMD to TB BMD were compared using a multiple regression analysis. Probands (mean age 30 years) were engaged in 14 sports activities: rugby, soccer, other team sports, endurance running, fighting sports, bodybuilding, multiple weightbearing activities, swimming, swimming with flippers, biking, rowing, climbing, triathlon and multiple mixed activities. They stated that they were practising a physical activity at the amateur level: 7.1 h/week between the ages of 11 and 18 years and 9 h/week between age 18 years and the day of the interview (no significant difference between physical activities). Rowers and swimmers had low TB BMD (1.22 and 1.17 g/cm2) and low leg BMD (1.37 and 1.31 g/cm2). Participants in rugby, soccer, other team sports and fighting sports had a high TB BMD (1.27-1.35 g/cm2) and high leg BMD (1.41-1.5 g/cm2). For head BMD, there was no stastistical difference among the different groups. Constructed ratios pointed out the site-specific adaptation of the skeleton: soccer player and runners had a higher leg ratio; bodybuilders, fighters, climbers and swimmers had a higher arm ratio; rugby players had a higher spine ratio. Head ratio was higher in non-weightbearing sports (rowing, swimming) than in weightbearing sports (rugby, team sports, soccer, fighting sports and bodybuilding). Thus the BMD and ratio differences among the 14 disciplines seem to be site-specific and related to the supposedly high and unusual strains created at certain sites during sport training by muscle stress and gravitational forces. Head ratio is closely related to the type of practice; its value

  4. Effects of various midsole densities of basketball shoes on impact attenuation during landing activities.

    PubMed

    Zhang, Songning; Clowers, Kurt; Kohstall, Charles; Yu, Yeon-Joo

    2005-02-01

    The purpose of this study was to examine effects of shoe midsole densities and mechanical demands (landing heights) on impact shock attenuation and lower extremity biomechanics during a landing activity. Nine healthy male college athletes performed 5 trials of step-off landing in each of 9 test conditions, i.e., a combination of landings in shoes of 3 midsole densities (soft, normal, hard) from each of 3 landing potential energy (PE) levels (low, median, high). Ground reaction forces (GRF), accelerations (ACC) of the tibia and forehead, and sagittal kinematic data were sampled simultaneously. A 3 x 3 two-way (surface x height) repeated-measures analysis of variance (ANOVA) was performed on selected kinematic, ACC, and GRF variables; a 3 x 3 x 3 three-way (surface x height x joint) ANOVA was performed on variables related to eccentric muscular work. The GRF results showed that the forefoot peak GRF in the normal and hard midsoles was significantly greater than the soft midsole at the low and median PEs. Rearfoot peak GRF was significantly greater for the hard midsole than for the soft and normal midsoles at the median and high PEs, respectively. The peak head and tibia peak ACC were also attenuated in similar fashion. Kinematic variables did not vary significantly across different midsoles, nor did energy absorbed through lower extremity extensors in response to the increased shoe stiffness. Knee joint extensors were shown to be dominant in attenuating the forefoot impact force across the landing heights. The results showed limited evidence of impact-attenuating benefits of the soft midsole in the basketball shoes.

  5. Insecticidal activity of essential oil of Carum Carvi fruits from China and its main components against two grain storage insects.

    PubMed

    Fang, Rui; Jiang, Cai Hong; Wang, Xiu Yi; Zhang, Hai Ming; Liu, Zhi Long; Zhou, Ligang; Du, Shu Shan; Deng, Zhi Wei

    2010-12-20

    During our screening program for agrochemicals from Chinese medicinal herbs and wild plants, the essential oil of Carum carvi fruits was found to possess strong contact toxicity against Sitophilus zeamais and Tribolium castaneum adults, with LD₅₀ values of 3.07 and 3.29 μg/adult, respectively, and also showed strong fumigant toxicity against the two grain storage insects with LC₅₀ values of 3.37 and 2.53 mg/L, respectively. The essential oil obtained by hydrodistillation was investigated by GC and GC-MS. The main components of the essential oil were identified to be (R)-carvone (37.98%) and D-limonene (26.55%) followed by α-pinene (5.21), cis-carveol (5.01%) and β-myrcene (4.67%). (R)-Carvone and D-limonene were separated and purified by silica gel column chromatography and preparative thin layer chromatography, and further identified by means of physicochemical and spectrometric analysis. (R)-Carvone and D-limonene showed strong contact toxicity against S. zeamais (LD₅₀ = 2.79 and 29.86 μg/adult) and T. castaneum (LD₅₀ = 2.64 and 20.14 μg/adult). (R)-Carvone and D-limonene also possessed strong fumigant toxicity against S. zeamais (LC₅₀ = 2.76 and 48.18 mg/L) and T. castaneum adults (LC₅₀ = 1.96 and 19.10 mg/L).

  6. Factors determining accumulation of mycotoxin producers in cereal grain during harvesting.

    PubMed

    Lugauskas, Albinas; Raila, Algirdas; Zvicevicius, Egidijus; Railiene, Marija; Novosinskas, Henrikas

    2007-01-01

    During the meteorologically contrasting period of 2003-2005, the contamination of winter wheat, malt barley and fodder barley grain with micromycetes during grain harvesting and preparation for storage was investigated. Micromycetes of over 70 species ascribed to 16 genera were isolated and identified, the density of their populations in grain was determined. Micromycetes with a population density of >50% were attributed to dominant species. Short biological characteristic, ecological peculiarities of the dominating micromycetes are provided; factors determining intensity of their development and abilities to synthesise and excrete toxic metabolites are indicated. The importance of grain drying for stabilisation of its contamination with micromycete propagules is highlighted. It is noted that in grain dried in shaft dryer using air at 90 degrees C the number of cfu (colony forming units) was reduced from 2.2 to 8.2 times. When active ventilation is applied, conditions favourable for the development of micromycetes remain longest in the upper layers of the mound. The airflow passing through the layer of damp grain inhibits the development of micromycetes, but an increase of comparative air flow for more than 500 m3x(txh)(-1) did not reduce the abundance of micromycete cfu. After drying Alternaria alternata, Fusarium avenaceum, F. culmorum, Penicillum verrucosum dominated in wheat grain; Aspergillus flavus, Bipolaris sorokiniana, Fusarium chlamydosporum, F. culmorum, F. tricinctum in malts barley grain; Fusarium avenaceum, F. culmorum, F. tricinctum, Alternaria alternata in fodder barley grain. It has been determined that all micromycetes recorded on grain after drying are potential producers of toxic metabolites, i.e. are hazardous to human health.

  7. Grain Handling and Storage.

    ERIC Educational Resources Information Center

    Harris, Troy G.; Minor, John

    This text for a secondary- or postecondary-level course in grain handling and storage contains ten chapters. Chapter titles are (1) Introduction to Grain Handling and Storage, (2) Elevator Safety, (3) Grain Grading and Seed Identification, (4) Moisture Control, (5) Insect and Rodent Control, (6) Grain Inventory Control, (7) Elevator Maintenance,…

  8. Grain Grading and Handling.

    ERIC Educational Resources Information Center

    Rendleman, Matt; Legacy, James

    This publication provides an introduction to grain grading and handling for adult students in vocational and technical education programs. Organized in five chapters, the booklet provides a brief overview of the jobs performed at a grain elevator and of the techniques used to grade grain. The first chapter introduces the grain industry and…

  9. Interstellar chemical differentiation across grain sizes

    NASA Astrophysics Data System (ADS)

    Ge, J. X.; He, J. H.; Li, Aigen

    2016-07-01

    In this work, we investigate the effects of ion accretion and size-dependent dust temperatures on the abundances of both gas-phase and grain-surface species. While past work has assumed a constant areal density for icy species, we show that this assumption is invalid and the chemical differentiation over grain sizes is significant. We use a gas-grain chemical code to demonstrate this numerically for two typical interstellar conditions: a dark cloud (DC) and a cold neutral medium (CNM). It is shown that, although the grain-size distribution variation (but with the total grain surface area unchanged) has little effect on the gas-phase abundances, it can alter the abundances of some surface species by up to ∼2-4 orders of magnitude. The areal densities of ice species are larger on smaller grains in the DC model as a consequence of ion accretion. However, the surface areal density evolution tracks are more complex in the CNM model due to the combined effects of ion accretion and dust temperature variation. The surface areal density differences between the smallest ( ∼ 0.01 μm) and the biggest ( ∼ 0.2 μm) grains can reach ∼1 and ∼5 orders of magnitude in the DC and CNM models, respectively.

  10. Fractal dust grains in plasma

    SciTech Connect

    Huang, F.; Peng, R. D.; Liu, Y. H.; Chen, Z. Y.; Ye, M. F.; Wang, L.

    2012-09-15

    Fractal dust grains of different shapes are observed in a radially confined magnetized radio frequency plasma. The fractal dimensions of the dust structures in two-dimensional (2D) horizontal dust layers are calculated, and their evolution in the dust growth process is investigated. It is found that as the dust grains grow the fractal dimension of the dust structure decreases. In addition, the fractal dimension of the center region is larger than that of the entire region in the 2D dust layer. In the initial growth stage, the small dust particulates at a high number density in a 2D layer tend to fill space as a normal surface with fractal dimension D = 2. The mechanism of the formation of fractal dust grains is discussed.

  11. Limitations of the potentiometric titration technique in determining the proton active site density of goethite surfaces

    NASA Astrophysics Data System (ADS)

    Lützenkirchen, Johannes; Boily, Jean-François; Lövgren, Lars; Sjöberg, Staffan

    2002-10-01

    Density of proton active surface sites at mineral surfaces is a property of fundamental importance in equilibrium modeling of surface complexation reactions. In this article, methods for an experimental determination of these sites at the surface of α-FeOOH (goethite) are explored. It is shown that previously obtained saturation data of goethite with respect to protons do not yield a site density that can be considered as an intrinsic sorbent property: the results are below crystallographically expected values and values for different ionic media in terms of composition and concentration yield different numbers - for example, chloride would yield higher values than nitrate at the same concentration, and higher electrolyte concentration would favor higher apparent maxima. Although site saturation might be explained by electrostatic repulsion, which is more efficient at high electrolyte concentration or for certain ions, further independent experimental results show that no saturation occurs on goethite down to ph ≡ -log[H +] = 2.2 and possibly to ph = 1.0 in 0.6 M NaCl. For those very low pH values, the experimental charging curve was obtained by coulometric back titration (using the Gran plot) or titrations with tris (hydroxymethyl)-aminomethane of the supernatant of acidified goethite suspension. These experimental data are to our knowledge the first high quality data at such low pHs. However, small errors in the determination of proton concentrations (1%) are shown to strongly affect the shape of the charging curve for ph < 2. Furthermore, goethite dissolution (proton consumption and iron reduction in coulometric titrations) and liquid junction effects interfere at low ph, hampering the straightforward application of coulometric Gran titrations over the whole pH range. From these experiments, it can nonetheless be ascertained that a minimum of 2.5 protons/nm 2 can be adsorbed at the goethite surface from the point of zero charge (ph 9.4) to pH 0.9. Although

  12. Radical formation, chemical processing, and explosion of interstellar grains

    NASA Technical Reports Server (NTRS)

    Greenberg, J. M.

    1976-01-01

    The ultraviolet radiation in interstellar space is shown to create a sufficient steady-state density of free radicals in the grain mantle material consisting of oxygen, carbon, nitrogen, and hydrogen to satisfy the critical condition for initiation of chain reactions. The criterion for minimum critical particle size for maintaining the chain reaction is of the order of the larger grain sizes in a distribution satisfying the average extinction and polarization measures. The triggering of the explosion of interstellar grains leading to the ejection of complex interstellar molecules is shown to be most probable where the grains are largest and where radiation is suddenly introduced; i.e., in regions of new star formation. Similar conditions prevail at the boundaries between very dark clouds and H II regions. When the energy released by the chemical activity of the free radicals is inadequate to explode the grain, the resulting mantle material must consist of extremely large organic molecules which are much more resistant to the hostile environment of H II regions than the classical dirty-ice mantles made up of water, methane, and ammonia.

  13. Structure-dependent charge density as a determinant of antimicrobial activity of peptide analogues of defensin.

    PubMed

    Bai, Yang; Liu, Shouping; Jiang, Ping; Zhou, Lei; Li, Jing; Tang, Charles; Verma, Chandra; Mu, Yuguang; Beuerman, Roger W; Pervushin, Konstantin

    2009-08-01

    Defensins are small (3-5 kDa) cysteine-rich cationic proteins found in both vertebrates and invertebrates constituting the front line of host innate immunity. Despite intensive research, bactericidal and cytotoxic mechanisms of defensins are still largely unknown. Moreover, we recently demonstrated that small peptides derived from defensins are even more potent bactericidal agents with less toxicity toward host cells. In this paper, structures of three C-terminal (R36-K45) analogues of human beta-defensin-3 were studied by 1H NMR spectroscopy and extensive molecular dynamics simulations. Because of indications that these peptides might target the inner bacterial membrane, they were reconstituted in dodecylphosphocholine or dodecylphosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] mixed micelles, and lipid bicelles mimicking the phospholipid-constituted bilayer membrane of mammalian and bacterial cells. The results show that the binding affinity and partitioning into the lipid phase and the ability to dimerize and accrete well-defined structures upon interactions with lipid membranes contribute to compactization of positive charges within peptide oligomers. The peptide charge density, mediated by corresponding three-dimensional structures, was found to directly correlate with the antimicrobial activity. These novel observations may provide a new rationale for the design of improved antimicrobial agents.

  14. Impact Ignition of Low Density Mechanically Activated and Multilayer Foil Ni/Al

    NASA Astrophysics Data System (ADS)

    Beason, Matthew; Mason, B.; Son, Steven; Groven, Lori

    2013-06-01

    Mechanical activation (MA) via milling of reactive materials provides a means of lowering the ignition threshold of shock initiated reactions. This treatment provides a finely mixed microstructure with wide variation in the resulting scales of the intraparticle microstructure that makes model validation difficult. In this work we consider nanofoils produced through vapor deposition with well defined periodicity and a similar degree of fine scale mixing. This allows experiments that may be easier to compare with computational models. To achieve this, both equimolar Ni/Al powder that has undergone MA using high energy ball milling and nanofoils milled into a powder using low energy ball milling were used. The Asay Shear impact experiment was conducted on both MA Ni/Al and Ni/Al nanofoil-based powders at low densities (<60%) to examine their impact response and reaction behavior. Scanning electron microscopy and energy-dispersive x-ray spectroscopy were used to verify the microstructure of the materials. The materials' mechanical properties were evaluated using nano-indentation. Onset temperatures were evaluated using differential thermal analysis/differential scanning calorimetry. Impact ignition thresholds, burning rates, temperature field, and ignition delays are reported. Funding from the Defense Threat Reduction Agency (DTRA) Grant Number HDTRA1-10-1-0119. Counter-WMD basic research program, Dr. Suhithi M. Peiris, program director is gratefully acknowledged.

  15. THE FIRST HARD X-RAY POWER SPECTRAL DENSITY FUNCTIONS OF ACTIVE GALACTIC NUCLEUS

    SciTech Connect

    Shimizu, T. Taro; Mushotzky, Richard F.

    2013-06-10

    We present results of our power spectral density (PSD) analysis of 30 active galactic nuclei (AGNs) using the 58 month light curves from Swift's Burst Alert Telescope (BAT) in the 14-150 keV band. PSDs were fit using a Monte Carlo based algorithm to take into account windowing effects and measurement error. All but one source were found to be fit very well using an unbroken power law with a slope of {approx} - 1, consistent at low frequencies with previous studies in the 2-10 keV band, with no evidence of a break in the PSD. For five of the highest signal-to-noise ratio sources, we tested the energy dependence of the PSD and found no significant difference in the PSD at different energies. Unlike previous studies of X-ray variability in AGNs, we do not find any significant correlations between the hard X-ray variability and different properties of the AGN including luminosity and black hole mass. The lack of break frequencies and correlations seem to indicate that AGNs are similar to the high state of Galactic black holes.

  16. Performance of Density Functionals for Activation Energies of Zr-Mediated Reactions.

    PubMed

    Sun, Yuanyuan; Chen, Hui

    2013-11-12

    Coupled cluster CCSD(T) calculations with core-valence correlation and complete basis set (CBS) limit extrapolation are used to benchmark the performance of commonly used density functionals in computing energy barriers for Zr-mediated reactions involving zirconocene species. These reactions include (a) insertions of the Zr-H bond of Cp2Zr(H)Cl into C═C, C≡C, and C═O bonds and (b) C-H activations by Zr═N bond in Cp2Zr═NH. The best performing functionals are M06-L, M06, and M06-2X in the M06 series, all having mean unsigned deviations (MUD) less than 2 kcal/mol. The worst performing functional is OLYP, with a distinctly large MUD of more than 10 kcal/mol. Considering also the trends in barrier heights and the systematic barrier height deviation, our best recommended functional is M06-2X. In this work, DFT empirical dispersion correction (DFT-D3) is found to improve the performance of barrier height values for most functionals (especially of OLYP and B3LYP). With DFT empirical dispersion correction, we also recommend M06-2X for reaction barrier calculations of Zr-mediated reactions.

  17. Oxidized low density lipoprotein increases acetylcholinesterase activity correlating with reactive oxygen species production.

    PubMed

    Yamchuen, Panit; Aimjongjun, Sathid; Limpeanchob, Nanteetip

    2014-12-01

    Hyperlipidemia, low density lipoproteins (LDL) and their oxidized forms, and oxidative stress are suspected to be a key combination in the onset of AD and acetylcholinesterase (AChE) plays a part in this pathology. The present study aimed to link these parameters using differentiated SH-SY5Y human neuroblastoma cells in culture. Both mildly and fully oxidized human LDL (mox- and fox-LDL), but not native (non-oxidized) LDL were cytotoxic in dose- and time-dependent patterns and this was accompanied by an increased production of intracellular reactive oxygen species (ROS). Oxidized LDL (10-200 μg/mL) augmented AChE activity after 4 and 24h treatments, respectively while the native LDL was without effect. The increased AChE with oxidized LDLs was accompanied by a proportionate increase in intracellular ROS formation (R=0.904). These findings support the notion that oxidized LDLs are cytotoxic and that their action on AChE may reduce central cholinergic transmission in AD and affirm AChE as a continued rational for anticholinesterase therapy but in conjunction with antioxidant/antihyperlipidemic cotreatments.

  18. Investigation of the density wave activity in the thermosphere above 220 KM

    NASA Astrophysics Data System (ADS)

    Illés-Almár, E.; Almár, I.; Bencze, P.

    Based on CACTUS (Capteur Accélérométrique Capacitif Triaxial Ultra Sensible) microaccelerometer measurements it has been demonstrated that - after taking into account all effects included in the MSIS'86=CIRA'86 (COSPAR, 1988) model - there are residual fluctuations in the density of the upper atmosphere much larger than that the accuracy of the measurements can account for. These fluctuations are attributed to some kind of wave activity (Illés-Almár, 1993, Illés-Almár et al. 1996a). The average deviations from a model are considered as a measure of the amplitude of the waves in the atmosphere and are analysed as a function of geomagnetic coordinates, altitude and local solar time, in order to identify possible wave sources either in the lower lying atmosphere or in the thermosphere/ionosphere system. As a first step, the present investigation intends to make a map of the wave pattern by this method.

  19. Strain energy density gradients in bone marrow predict osteoblast and osteoclast activity: a finite element study.

    PubMed

    Webster, Duncan; Schulte, Friederike A; Lambers, Floor M; Kuhn, Gisela; Müller, Ralph

    2015-03-18

    Huiskes et al. hypothesized that mechanical strains sensed by osteocytes residing in trabecular bone dictate the magnitude of load-induced bone formation. More recently, the mechanical environment in bone marrow has also been implicated in bone׳s response to mechanical stimulation. In this study, we hypothesize that trabecular load-induced bone formation can be predicted by mechanical signals derived from an integrative µFE model, incorporating a description of both the bone and marrow phase. Using the mouse tail loading model in combination with in vivo micro-computed tomography (µCT) we tracked load induced changes in the sixth caudal vertebrae of C57BL/6 mice to quantify the amount of newly mineralized and eroded bone volumes. To identify the mechanical signals responsible for adaptation, local morphometric changes were compared to micro-finite element (µFE) models of vertebrae prior to loading. The mechanical parameters calculated were strain energy density (SED) on trabeculae at bone forming and resorbing surfaces, SED in the marrow at the boundary between bone forming and resorbing surfaces, along with SED in the trabecular bone and marrow volumes. The gradients of each parameter were also calculated. Simple regression analysis showed mean SED gradients in the trabecular bone matrix to significantly correlate with newly mineralized and eroded bone volumes R(2)=0.57 and 0.41, respectively, p<0.001). Nevertheless, SED gradients in the marrow were shown to be the best predictor of osteoblastic and osteoclastic activity (R(2)=0.83 and 0.60, respectively, p<0.001). These data suggest that the mechanical environment of the bone marrow plays a significant role in determining osteoblast and osteoclast activity.

  20. Effect of sports activity on bone mineral density in wheelchair athletes.

    PubMed

    Miyahara, Kimiko; Wang, Da-Hong; Mori, Keiko; Takahashi, Kayo; Miyatake, Nobuyuki; Wang, Bing-Ling; Takigawa, Tomoko; Takaki, Jiro; Ogino, Keiki

    2008-01-01

    The present study carried out a measurement of body composition and a nutrition survey, targeting 28 male wheelchair athletes and comparing them with 25 male physically able healthy athletes as the controls. The DXA method was used to measure bone mineral density (BMD), percentage of body fat (% body fat), and lean body mass (LBM). Possible factors affecting the BMD of the wheelchair athletes with spinal injuries were analyzed including age, body part, type of sport, area of injury, length of injury, and the length of time it took before restarting sports activity after injury. BMD in the arms, body trunk, legs, and entire body was measured. There were no significant differences in the BMD of the wheelchair athletes by age group (from 20 to 29, from 30 to 39, and 40 years and older), by sports (basketball, track and field, and tennis), and by area of injury (high and low paraplegia). BMD in the legs (r = -0.549, P < 0.01), body trunk (r = -0.414, P < 0.05), and entire body (r = -0.452, P < 0.05) of the wheelchair athletes was negatively correlated with the period since injury; however, no such a relationship was observed in the arms. In addition, the multiple regression analysis for BMD of each body region showed that the earlier the wheelchair athletes restarted sports after injury, the higher values the BMD of legs (r = -0.467, P < 0.05), body trunk (r = -0.469, P < 0.05), and entire body (r = -0.488, P < 0.05), independent of age and sports. The leg BMD of the wheelchair athletes was lower than that of the physically able athletes, with a BMD 76.5% of the controls. The present study suggests that restarting sports activity in a timely manner after treatment and rehabilitation for the injury is useful in preventing loss of BMD in wheelchair athletes and ultimately improving their quality of life.

  1. O(minus 2) grain boundary diffusion and grain growth in pure dense MgO

    NASA Technical Reports Server (NTRS)

    Kapadia, C. M.; Leipold, M. H.

    1973-01-01

    Grain growth behavior in fully dense compacts of MgO of very high purity was studied, and the results compared with other similar behaving materials. The activation energy for the intrinsic self-diffusion of Mg(2minus) is discussed along with the grain boundary diffusion of O(2minus). Grain boundary diffusion of O(2minus) is proposed as the controlling mechanism for grain growth.

  2. Evaluation of enzyme activity and fiber content of soybean cotyledon fiber and distiller's dried grains with solubles by solid state fermentation.

    PubMed

    Yang, Shengli; Lio, JunYi; Wang, Tong

    2012-05-01

    To increase the value of coproducts from corn ethanol fermentation and soybean aqueous processing, distiller's dried grains with solubles (DDGS) and soybean cotyledon fiber were used as the substrates for solid state fermentation (SSF) to improve feed digestibility. Aspergillus oryzae, Trichoderma reesei, and Phanerochaete chrysosporium were chosen as they produce desirable enzymes and are widely used in SSF for feed. The results showed that the cellulase and xylanase activities were significantly increased after 7 days of fermentation, and cellulose and hemicellulose degradation was also greatly increased. When soybean fiber was used as SSF substrate, the maximum activities of the cellulase and xylanase were 10.3 and 84.2 IU/g substrate (dry weight basis) after SSF treatment, respectively. However, the enzyme activities were relatively low in DDGS, and the growth of the three fungi was poor. The fungi grew better when soybean cotyledon fiber was added to DDGS, and cellulase and xylanase activity increased with the increase of soybean fiber content. Porosity was identified as an important factor for SSF because the addition of inert soybean hull alone improved the fungi growth significantly. These data suggest that the nutritional value of DDGS and soybean cotyledon fiber as monogastric animal feed could be greatly enhanced by SSF treatment.

  3. Declining densities and reproductive activities of the queen conch Strombus gigas (Mesogastropoda: Strombidae) in Banco Chinchorro, eastern Caribbean, Mexico.

    PubMed

    De Jesús-Navarrete, Alberto; Valencia-Hernández, Adriana

    2013-12-01

    Queen conch is a gastropod inhabiting the Caribbean Sea, it represents the second largest fishery after the spiny lobster, but it has been extensively captured in the area. In order to know its population status in Chinchorro Bank, we determined conch density changes and its effects on reproductive activities, between July and November 2009. For this, data on conch density, morphology and reproductive activities were obtained from 15 sites within three fishing zones, and compared with previously collected data (1990, 1992, 1994, and 1997). Data showed that adult density decreased with time, from 10,700 ind./ha in 1990, to 198 ind./h in 2009. Neither egg masses nor spawns were found and mating was only observed once in July 2009. In July, adult (lip>4 mm) density in the Southern zone was 23 ind./ha whereas in the Northern zone and Central zone densities were 15 and 9ind./ha respectively. In November, density was somewhat higher: Southern zone 96 ind./ha; Central zone 39 ind./ha and Northern zone had 38ind./ha. In July, mean shell length was 170.80 +/- 46.28 mm, with a higher median abundance at 180-189 mm. In November, higher frequency was 187.63 +/- 45.14 mm, maximumat 210-219 mm interval. For the last 10 years period, mean adult conch densities have diminished in each zone, which might be the main cause of decreased reproductive activities of the conch at Banco Chinchorro. It is therefore an immediate need to analyse the management plan for this species in this Reserve and perhaps to promote a re-population of queen conch and culture activities.

  4. Declining densities and reproductive activities of the queen conch Strombus gigas (Mesogastropoda: Strombidae) in Banco Chinchorro, eastern Caribbean, Mexico.

    PubMed

    De Jesús-Navarrete, Alberto; Valencia-Hernández, Adriana

    2013-12-01

    Queen conch is a gastropod inhabiting the Caribbean Sea, it represents the second largest fishery after the spiny lobster, but it has been extensively captured in the area. In order to know its population status in Chinchorro Bank, we determined conch density changes and its effects on reproductive activities, between July and November 2009. For this, data on conch density, morphology and reproductive activities were obtained from 15 sites within three fishing zones, and compared with previously collected data (1990, 1992, 1994, and 1997). Data showed that adult density decreased with time, from 10,700 ind./ha in 1990, to 198 ind./h in 2009. Neither egg masses nor spawns were found and mating was only observed once in July 2009. In July, adult (lip>4 mm) density in the Southern zone was 23 ind./ha whereas in the Northern zone and Central zone densities were 15 and 9ind./ha respectively. In November, density was somewhat higher: Southern zone 96 ind./ha; Central zone 39 ind./ha and Northern zone had 38ind./ha. In July, mean shell length was 170.80 +/- 46.28 mm, with a higher median abundance at 180-189 mm. In November, higher frequency was 187.63 +/- 45.14 mm, maximumat 210-219 mm interval. For the last 10 years period, mean adult conch densities have diminished in each zone, which might be the main cause of decreased reproductive activities of the conch at Banco Chinchorro. It is therefore an immediate need to analyse the management plan for this species in this Reserve and perhaps to promote a re-population of queen conch and culture activities. PMID:24432527

  5. Variation of D-region nitric-oxide density with solar activity and season at the dip equator

    NASA Technical Reports Server (NTRS)

    Chakrabarty, D. K.; Pakhomov, S. V.; Beig, G.

    1989-01-01

    To study the solar control on electron density (N sub e) in the equatorial D region, a program was initiated with Soviet collaboration in 1979. A total of 31 rockets were launched during the high solar activity period, and 47 rockets during the low solar activity period, from Thumba to measure the N sub e profiles. Analysis of the data shows that the average values of N sub e for the high solar activity period are higher by a factor of about 2 to 3 compared to the low solar activity values. It was found that a single nitric oxide density, (NO), profile cannot reproduce all the observed N sub e profiles. An attempt was made to reproduce theoretically the observed N sub e profiles by introducing variation in (NO) for the different solar activity periods and seasons.

  6. Radionuclide Activities in Contaminated Soils: Effects of Sampling Bias on Remediation of Coarse-Grained Soils in Hanford Formation

    SciTech Connect

    Mattigod, Shas V.; Martin, Wayne J.

    2001-08-28

    Only a limited set of particle size-contaminant concentration data is available for soils from the Hanford Site. These data are based on bench-scale tests on single soil samples from one waste site each in operable units 100-BC-1, 100-DR-1, and 100-FR-1, and three samples from the North Pond 300-FF-1 operable unit. The objective of this study was to 1) examine available particle size-contaminant of concern activity and concentration data for 100 and 300 Area soils, 2) assess the effects of sampling bias, 3) suggest sampling protocols, and 4) formulate a method to determine the contaminant of concern activities and concentrations of the whole soil based on the measurements conducted on a finer size fraction of the whole soil.

  7. Angiotensin I-Converting Enzyme inhibitory and antioxidant activities and surfactant properties of protein hydrolysates as obtained of Amaranthus hypochondriacus L. grain.

    PubMed

    Soriano-Santos, J; Escalona-Buendía, H

    2015-04-01

    Even though some research has been carried out on surfactant properties of amaranth protein hydrolysates, their bio-functionality has not been studied yet. In this work amaranth grain Alb 1 and Glob were hydrolyzed (Alb 1H, Glob H) and foams and emulsions at optimal conditions (t, E/S, pH5) were prepared in order to assess techno-functional properties such as foaming (F) and emulsifying (E) (capacity (C) and stability (S)). FC and EC were much better for Glob H than for Alb H. Angiotensin I-converting enzyme-inhibitory activity was higher for Alb 1H (roughly 50 %) than that of Glob H (roughly 30 %). Scavenging of radicals activity (DPPH· or ABTS· (+) ) of Alb 1H and Glob H, at 2 mg/mL, was similar (approx. 40 %), but lower than Alb 1 (approx. 70 %), which was the best antioxidant. The low reducing power showed that hydrolysates barely donate an electron or hydrogen. Chelating activity on Cu(2+) was lower than that exhibited by Fe(2+,) which was remarkable, approx. 80 % as long as DH% > 10 %, where hydrolysates displayed high solubility (Alb 1H = 85 %, Glob H = 70 %) because of occurrence of 1-10 kDa peptides. Amaranth foams and emulsions prepared with protein hydrolysates have a potential as a nutraceutical food.

  8. Angiotensin I-Converting Enzyme inhibitory and antioxidant activities and surfactant properties of protein hydrolysates as obtained of Amaranthus hypochondriacus L. grain.

    PubMed

    Soriano-Santos, J; Escalona-Buendía, H

    2015-04-01

    Even though some research has been carried out on surfactant properties of amaranth protein hydrolysates, their bio-functionality has not been studied yet. In this work amaranth grain Alb 1 and Glob were hydrolyzed (Alb 1H, Glob H) and foams and emulsions at optimal conditions (t, E/S, pH5) were prepared in order to assess techno-functional properties such as foaming (F) and emulsifying (E) (capacity (C) and stability (S)). FC and EC were much better for Glob H than for Alb H. Angiotensin I-converting enzyme-inhibitory activity was higher for Alb 1H (roughly 50 %) than that of Glob H (roughly 30 %). Scavenging of radicals activity (DPPH· or ABTS· (+) ) of Alb 1H and Glob H, at 2 mg/mL, was similar (approx. 40 %), but lower than Alb 1 (approx. 70 %), which was the best antioxidant. The low reducing power showed that hydrolysates barely donate an electron or hydrogen. Chelating activity on Cu(2+) was lower than that exhibited by Fe(2+,) which was remarkable, approx. 80 % as long as DH% > 10 %, where hydrolysates displayed high solubility (Alb 1H = 85 %, Glob H = 70 %) because of occurrence of 1-10 kDa peptides. Amaranth foams and emulsions prepared with protein hydrolysates have a potential as a nutraceutical food. PMID:25829587

  9. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    NASA Astrophysics Data System (ADS)

    Bártová, H.; Kučera, J.; Musílek, L.; Trojek, T.

    2014-11-01

    In order to evaluate the age from the equivalent dose and to obtain an optimized and efficient procedure for thermoluminescence (TL) dating, it is necessary to obtain the values of both the internal and the external dose rates from dated samples and from their environment. The measurements described and compared in this paper refer to bricks from historic buildings and a fine-grain dating method. The external doses are therefore negligible, if the samples are taken from a sufficient depth in the wall. However, both the alpha dose rate and the beta and gamma dose rates must be taken into account in the internal dose. The internal dose rate to fine-grain samples is caused by the concentrations of natural radionuclides 238U, 235U, 232Th and members of their decay chains, and by 40K concentrations. Various methods can be used for determining trace concentrations of these natural radionuclides and their contributions to the dose rate. The dose rate fraction from 238U and 232Th can be calculated, e.g., from the alpha count rate, or from the concentrations of 238U and 232Th, measured by neutron activation analysis (NAA). The dose rate fraction from 40K can be calculated from the concentration of potassium measured, e.g., by X-ray fluorescence analysis (XRF) or by NAA. Alpha counting and XRF are relatively simple and are accessible for an ordinary laboratory. NAA can be considered as a more accurate method, but it is more demanding regarding time and costs, since it needs a nuclear reactor as a neutron source. A comparison of these methods allows us to decide whether the time- and cost-saving simpler techniques introduce uncertainty that is still acceptable.

  10. Activities on heavy ion inertial fusion and beam-driven high energy density science in Japan

    NASA Astrophysics Data System (ADS)

    Horioka, K.; Kawamura, T.; Nakajima, M.; Kondo, K.; Ogawa, M.; Oguri, Y.; Hasegawa, J.; Kawata, S.; Kikuchi, T.; Sasaki, T.; Murakami, M.; Takayama, K.

    2009-07-01

    Recent research activities in Japan relevant to heavy ion fusion (HIF) are presented. During the past two years, significant progress in HIF and high energy density (HED) physics research has been made by a number of research groups in universities and accelerator facilities. Evolutions in phase space during the longitudinal compression of intense beams were investigated at UU-NUT-TIT. Beam-plasma interaction experiments and related theoretical studies are in progress at RLNR-TIT. In the study, shock-heated hydrogen was used for the interaction experiments as a well-defined non-ideal-plasma target. In the beam-plasma interaction experiments, a special emphasis is placed on an evaluation of non-linear effects on the stopping power in a beam-heated plasma target. A direct-indirect hybrid scheme of a beam-driven ICF target has been proposed and discussed at UU. In the same group, a method for controlling the Rayleigh-Taylor instability in imploding fuel target has been proposed using oscillating heavy ion beams (HIBs). Core dynamics of the impact ignition has been investigated both experimentally and numerically at ILE—Osaka. Dense plasmas driven by intense ion beams and/or a pulse powered device, were evaluated by a group of DES-TIT, concerning the researches on HED and warm dense matter (WDM) physics. A quasi-statically tamped target was proposed to make a well-defined, warm dense state for equation-of-state (EOS) studies based on ion accelerators. The potentiality of the new facility planned at KEK was evaluated by a collaborating group of TIT-UU-KEK, which can extend the parameter regime for laboratory experiments to study the properties of matter under extreme conditions. A possible method to make a high-pressure condition for study of the planetary science was discussed as a short-term subject of intense HIBs.

  11. ACTIVE CATHODES FOR SUPER-HIGH POWER DENSITY SOLID OXIDE FUEL CELLS THROUGH SPACE CHARGE EFFECTS

    SciTech Connect

    Anil V. Virkar

    2004-05-17

    This report summarizes the work done during the sixth quarter of the project. Effort was directed in three areas: (1) Further development of the model on the role of connectivity on ionic conductivity of porous bodies, including the role of grain boundaries and space charge region. (2) Calculation of the effect of space charge and morphology of porous bodies on the effective charge transfer resistance of porous composite cathodes. (3) The investigation of the three electrode system for the measurement of cathodic polarization using amperometric sensors.

  12. Power Spectral Density Analysis of Electrodermal Activity for Sympathetic Function Assessment.

    PubMed

    Posada-Quintero, Hugo F; Florian, John P; Orjuela-Cañón, Alvaro D; Aljama-Corrales, Tomas; Charleston-Villalobos, Sonia; Chon, Ki H

    2016-10-01

    Time-domain features of electrodermal activity (EDA), the measurable changes in conductance at the skin surface, are typically used to assess overall activation of the sympathetic system. These time domain features, the skin conductance level (SCL) and the nonspecific skin conductance responses (NS.SCRs), are consistently elevated with sympathetic nervous arousal, but highly variable between subjects. A novel frequency-domain approach to quantify sympathetic function using the power spectral density (PSD) of EDA is proposed. This analysis was used to examine if some of the induced stimuli invoke the sympathetic nervous system's dynamics which can be discernible as a large spectral peak, conjectured to be present in the low frequency band. The resulting indices were compared to the power of low-frequency components of heart rate variability (HRVLF) time series, as well as to time-domain features of EDA. Twelve healthy subjects were subjected to orthostatic, physical and cognitive stress, to test these techniques. We found that the increase in the spectral powers of the EDA was largely confined to 0.045-0.15 Hz, which is in the prescribed band for HRVLF. These low frequency components are known to be, in part, influenced by the sympathetic nervous dynamics. However, we found an additional 5-10% of the spectral power in the frequency range of 0.15-0.25 Hz with all three stimuli. Thus, dynamics of the normalized sympathetic component of the EDA, termed EDASympn, are represented in the frequency band 0.045-0.25 Hz; only a small amount of spectral power is present in frequencies higher than 0.25 Hz. Our results showed that the time-domain indices (the SCL and NS.SCRs), and EDASympn, exhibited significant increases under orthostatic, physical, and cognitive stress. However, EDASympn was more responsive than the SCL and NS.SCRs to the cold pressor stimulus, while the latter two were more sensitive to the postural and Stroop tests. Additionally, EDASympn exhibited an

  13. Antifungal activity of essential oil of Ziziphora clinopodioides and the inhibition of aflatoxin B1 production in maize grain.

    PubMed

    Moghadam, Hediyeh Davoudi; Sani, Ali Mohamadi; Sangatash, Masoomeh Mehraban

    2016-03-01

    The aim of this study was to determine the antifungal effect of the essential oil obtained from Ziziphora clinopodioides L on two fungi species including Aspergillus flavus and Aspergillus parasiticus using microdilution method. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined for the essential oil at 10 different concentrations (i.e. 25,000, 12,500, 6250, 3125, 1562.5, 781.25, 390.625, 195.31, 97.65, and 48.82 µg/ml). Finally, the effect of the essential oil at six levels (6250, 3125, 1600, 800, 400, and 196 µg/ml) was investigated on the growth and activity of A. flavus and A. parasiticus, and also toxin production of these species in maize at 0.97 aw and 25°C after 29 days. Aflatoxin B1 (AFB1) content was assayed by enzyme linked immuno-sorbent assay technique. Results showed that essential oil of Z. clinopodioides was found more effective on A. parasiticus than A. flavus in both in vitro and in vivo conditions. Z. clinopodioides oil exhibited the same MIC value in the liquid medium against all fungal strains (48.82 µg/ml), while it showed different activity against A. flavus and A. parasiticus with MFC values of 781.25 and 390.625 µg/ml respectively. Under storage condition in maize, AFB1 production was significantly (p < 0.05) repressed at the concentration of 6250 µg/ml for A. flavus and 6250 and 3125 µg/ml for A. parasiticus. At the lower concentrations, the AFB1 production increased gradually. The results of the present study indicated that the essential oil of Z. clinopodioides had significant antifungal activity (p < 0.05); therefore, it can be used as an antifungal agent in the food and medicinal industries.

  14. Tuning sensitivity of CAR to EGFR density limits recognition of normal tissue while maintaining potent anti-tumor activity

    PubMed Central

    Caruso, Hillary G.; Hurton, Lenka V.; Najjar, Amer; Rushworth, David; Ang, Sonny; Olivares, Simon; Mi, Tiejuan; Switzer, Kirsten; Singh, Harjeet; Huls, Helen; Lee, Dean A.; Heimberger, Amy B.; Champlin, Richard E.; Cooper, Laurence J. N.

    2015-01-01

    Many tumors over express tumor-associated antigens relative to normal tissue, such as epidermal growth factor receptor (EGFR). This limits targeting by human T cells modified to express chimeric antigen receptors (CARs) due to potential for deleterious recognition of normal cells. We sought to generate CAR+ T cells capable of distinguishing malignant from normal cells based on the disparate density of EGFR expression by generating two CARs from monoclonal antibodies which differ in affinity. T cells with low affinity Nimo-CAR selectively targeted cells over-expressing EGFR, but exhibited diminished effector function as the density of EGFR decreased. In contrast, the activation of T cells bearing high affinity Cetux-CAR was not impacted by the density of EGFR. In summary, we describe the generation of CARs able to tune T-cell activity to the level of EGFR expression in which a CAR with reduced affinity enabled T cells to distinguish malignant from non-malignant cells. PMID:26330164

  15. Beyond Density: An Inquiry-Based Activity Involving Students Searching for Relationships.

    ERIC Educational Resources Information Center

    DeMeo, Stephen

    2001-01-01

    Explains the limitations of a traditional density experiment and presents an inquiry-based laboratory experiment which allows students to develop an understanding on the relationship between the object's properties and the volume of water the object displaces. (YDS)

  16. Bone Mineral Density Changes after Physical Training and Calcium Intake in Students with Attention Deficit and Hyper Activity Disorders

    ERIC Educational Resources Information Center

    Arab ameri, Elahe; Dehkhoda, Mohammad Reza; Hemayattalab, Rasool

    2012-01-01

    In this study we investigate the effects of weight bearing exercise and calcium intake on bone mineral density (BMD) of students with attention deficit and hyper activity (ADHD) disorder. For this reason 54 male students with ADHD (age 8-12 years old) were assigned to four groups with no differences in age, BMD, calcium intake, and physical…

  17. ERK1/2 Activation Is Necessary for BDNF to Increase Dendritic Spine Density in Hippocampal CA1 Pyramidal Neurons

    ERIC Educational Resources Information Center

    Alonso, Mariana; Medina, Jorge H.; Pozzo-Miller, Lucas

    2004-01-01

    Brain-derived neurotrophic factor (BDNF) is a potent modulator of synaptic transmission and plasticity in the CNS, acting both pre- and postsynaptically. We demonstrated recently that BDNF/TrkB signaling increases dendritic spine density in hippocampal CA1 pyramidal neurons. Here, we tested whether activation of the prominent ERK (MAPK) signaling…

  18. Effect of long-term unilateral activity on bone mineral density of female junior tennis players.

    PubMed

    Haapasalo, H; Kannus, P; Sievänen, H; Pasanen, M; Uusi-Rasi, K; Heinonen, A; Oja, P; Vuori, I

    1998-02-01

    distal radius), no significant BMD differences were found between the players and controls in any Tanner stage. In the correlation analysis, the Tanner I and II players (mean ages 9.4 and 10.8 years) showed no significant associations between any of the predictive variables and the side-to-side BMD differences, while in Tanner stages III, IV, and V, such associations could be found; the total amount of training hours during the playing career and the number of training sessions per week showed a significant and systematic correlation (rs ranging from 0.43 to 0.80) with the side-to-side BMD differences in several measured bone sites. In conclusion, this study suggests that in a majority of female junior tennis players, the benefit of unilateral activity on bone density does not become clearly evident until the adolescent growth spurt or Tanner stage III. The total amount of training during the player's career and the current training frequency (sessions per week) seem to best explain the training effect on bone tissue, leaving, however, room for speculation on the still unknown factors that modulate the loading response of a growing bone. PMID:9495526

  19. Assessment of Toxicity, Antifeedant Activity, and Biochemical Responses in Stored-Grain Insects Exposed to Lethal and Sublethal Doses of Gaultheria procumbens L. Essential Oil.

    PubMed

    Kiran, S; Prakash, Bhanu

    2015-12-01

    The present study was undertaken to investigate the insecticidal activity of chemically characterized Gaultheria procumbens essential oil (EO) and its mode of action against the Coleopteran insects Sitophilus oryzae and Rhyzopertha dominica. Gas chromatography-mass spectrometry results depicted methyl salicylate (MS) as the major compound (96.61%) of EO. EO and its major compound methyl salicylate (MS) showed 100% mortality at 150 and 5.0 μL/L air against S. oryzae and R. dominica, respectively, on 24 h of exposure. The in vivo percent inhibition of AChE activity ranged between 6.12 and 27.50%. In addition, changes in the antioxidative defense system, superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and oxidized glutathione (GSSG), in test insects were estimated. A significant dose-dependent response in all test parameters was observed. The results demonstrated that G. procumbens EO could play a significant role in the formulation of EO-based insecticides for the management of stored-grain insects. PMID:26558484

  20. Marketing Farm Grain Crops.

    ERIC Educational Resources Information Center

    Ridenour, Harlan E.

    This vocational agriculture curriculum on grain marketing contains three parts: teacher guide, student manual, and student workbook. All three are coordinated and cross-referenced. The course is designed to give students of grain marketing a thorough background in the subject and provide practical help in developing grain marketing strategies for…

  1. Endothelial NOS-dependent activation of c-Jun NH(2)- terminal kinase by oxidized low-density lipoprotein

    NASA Technical Reports Server (NTRS)

    Go, Y. M.; Levonen, A. L.; Moellering, D.; Ramachandran, A.; Patel, R. P.; Jo, H.; Darley-Usmar, V. M.

    2001-01-01

    Oxidized low-density lipoprotein (oxLDL) is known to activate a number of signal transduction pathways in endothelial cells. Among these are the c-Jun NH(2)-terminal kinase (JNK), also known as stress-activated protein kinase, and extracellular signal-regulated kinase (ERK). These mitogen-activated protein kinases (MAP kinase) determine cell survival in response to environmental stress. Interestingly, JNK signaling involves redox-sensitive mechanisms and is activated by reactive oxygen and nitrogen species derived from both NADPH oxidases, nitric oxide synthases (NOS), peroxides, and oxidized low-density lipoprotein (oxLDL). The role of endothelial NOS (eNOS) in the activation of JNK in response to oxLDL has not been examined. Herein, we show that on exposure of endothelial cells to oxLDL, both ERK and JNK are activated through independent signal transduction pathways. A key role of eNOS activation through a phosphatidylinositol-3-kinase-dependent mechanism leading to phosphorylation of eNOS is demonstrated for oxLDL-dependent activation of JNK. Moreover, we show that activation of ERK by oxLDL is critical in protection against the cytotoxicity of oxLDL.

  2. The role of a-axis grains in the transition to the normal state of YBa{sub 2}Cu{sub 3}O{sub 7−δ} films and of 2G-coated conductors when induced by high electrical current densities

    SciTech Connect

    Bernstein, P. Harnois, C.; Mc Loughlin, C.; Noudem, J.; Thimont, Y.; Ferro, G.; Osorio, M. R.; Veira, J. A.; Vidal, D.; Vidal, F.

    2014-02-07

    The influence of surface defects, in particular of a-axis grains, on the transition to the normal state induced by high current densities in YBa{sub 2}Cu{sub 3}O{sub 7−δ} (YBCO) thin films and in a commercial 2G-coated conductor is investigated. For that purpose, the surface of the samples is observed by scanning electron microscopy and isothermal current-voltage curves are measured at different temperatures with pulsed currents up to the quenching value I*. The results show that the ratio of I* to the critical current is large if a-axis grains are not visible at the surface of the YBCO films, while it is much lower if the surface includes a-axis grains as this is the case for the coated conductor. The connection between the transition onset and the vortex dynamics, as well as the role of the a-axis grains in this process are discussed. The relation between the I* values obtained from thermal calculations and those resulting from vortex dynamics considerations is also discussed, as well as the possible consequences suggested by this work for the different applications of the coated conductors.

  3. [Value of physical activity for proper bone mass and bone mineral density attaining in children and adolescents].

    PubMed

    Bolanowski, Marek; Basiak, Aleksander; Bolanowski, Janusz; Sutkowski, Krzysztof

    2008-01-01

    Physical activity is an important factor for healthy life of the humans. Its significance regards mostly the developmental age, when natural mobility of the youth prones to the proper growing of the skeleton and is important in the prevention and therapy of many diseases. The advantageous effect of regular physical activity and different sport disciplines on bone mass and density is described. In the young age, puberty is an ideal moment for attaining the maximal bone mass and density gain due to physical exercising. The possible harmful effect of exaggerated physical activity has been shown. It is connected with hormonal disorders - secondary amenorrhea, delay of menarche, increased injuries and BMD loss together with significant body mass reduction.

  4. Pore size analysis of activated carbons from argon and nitrogen porosimetry using density functional theory

    SciTech Connect

    Dombrowski, R.J.; Hyduke, D.R.; Lastoskie, C.M.

    2000-05-30

    The authors present isotherms calculated from density functional theory for the adsorption of argon in model slit-shaped carbon pores at 77 K. The model isotherms are used to interpret experimental argon uptake measurements and to obtain the pore size distributions of several porous carbons. A similar set of density measurements and to obtain the pore size distributions of several porous carbons. A similar set of density functional theory isotherms, previously reported for nitrogen adsorption on carbon slit pores at 77 K, are used to determine pore size distributions for the same set of carbons. The pore size distribution maxima, mean pore widths, and specific pore volumes measured using the two different probe gases are all found to agree to within approximately 8% on average. Some of the differences in the pore size distributions obtained from argon and nitrogen porosimetry may be attributable to quadrupolar interactions of the nitrogen molecules with functional groups on the carbon surface.

  5. 3D grain boundary migration

    NASA Astrophysics Data System (ADS)

    Becker, J. K.; Bons, P. D.

    2009-04-01

    Microstructures of rocks play an important role in determining rheological properties and help to reveal the processes that lead to their formation. Some of these processes change the microstructure significantly and may thus have the opposite effect in obliterating any fabrics indicative of the previous history of the rocks. One of these processes is grain boundary migration (GBM). During static recrystallisation, GBM may produce a foam texture that completely overprints a pre-existing grain boundary network and GBM actively influences the rheology of a rock, via its influence on grain size and lattice defect concentration. We here present a new numerical simulation software that is capable of simulating a whole range of processes on the grain scale (it is not limited to grain boundary migration). The software is polyhedron-based, meaning that each grain (or phase) is represented by a polyhedron that has discrete boundaries. The boundary (the shell) of the polyhedron is defined by a set of facets which in turn is defined by a set of vertices. Each structural entity (polyhedron, facets and vertices) can have an unlimited number of parameters (depending on the process to be modeled) such as surface energy, concentration, etc. which can be used to calculate changes of the microstructre. We use the processes of grain boundary migration of a "regular" and a partially molten rock to demonstrate the software. Since this software is 3D, the formation of melt networks in a partially molten rock can also be studied. The interconnected melt network is of fundamental importance for melt segregation and migration in the crust and mantle and can help to understand the core-mantle differentiation of large terrestrial planets.

  6. Muscle activity, cross-sectional area, and density following passive standing and whole body vibration: A case series

    PubMed Central

    Masani, Kei; Alizadeh-Meghrazi, Milad; Sayenko, Dimitry G.; Zariffa, Jose; Moore, Cameron; Giangregorio, Lora; Popovic, Milos R.; Catharine Craven, B.

    2014-01-01

    Objective To investigate the effects of intermittent passive standing (PS) and whole body vibration (WBV) on the electromyography (EMG) activity, cross-sectional area, and density of lower extremity muscles in individuals with chronic motor complete spinal cord injury (SCI). Design Case series. Methods Seven adult men with chronic (≥2 years), thoracic motor complete (AIS A–B) SCI completed a 40-week course of thrice-weekly intermittent PS-WBV therapy, in a flexed knee posture (160°), for 45 minutes per session at a frequency of 45 Hz and 0.6–0.7 mm displacement using the WAVE® Pro Plate, with an integrated EasyStand™ standing frame. EMG was measured in major lower extremity muscles to represent muscle activity during PS-WBV. The cross-sectional area and density of the calf muscles were measured using peripheral quantitative computed tomography at the widest calf cross-section (66% of the tibia length) at pre- and post-intervention. All measured variables were compared between the pre- and post-intervention measurements to assess change after the PS-WBV intervention. Results PS-WBV acutely induced EMG activity in lower extremity muscles of SCI subjects. No significant changes in lower extremity EMG activity, muscle cross-sectional area, or density were observed following the 40-week intervention. Conclusions Although acute exposure to PS-WBV can induce electrophysiological activity of lower extremity muscles during PS in men with motor complete SCI, the PS-WBV intervention for 40 weeks was not sufficient to result in enhanced muscle activity, or to increase calf muscle cross-sectional area or density. PMID:25059652

  7. Irradiation-induced grain growth and defect evolution in nanocrystalline zirconia with doped grain boundaries.

    PubMed

    Dey, Sanchita; Mardinly, John; Wang, Yongqiang; Valdez, James A; Holesinger, Terry G; Uberuaga, Blas P; Ditto, Jeff J; Drazin, John W; Castro, Ricardo H R

    2016-06-22

    Grain boundaries are effective sinks for radiation-induced defects, ultimately impacting the radiation tolerance of nanocrystalline materials (dense materials with nanosized grains) against net defect accumulation. However, irradiation-induced grain growth leads to grain boundary area decrease, shortening potential benefits of nanostructures. A possible approach to mitigate this is the introduction of dopants to target a decrease in grain boundary mobility or a reduction in grain boundary energy to eliminate driving forces for grain growth (using similar strategies as to control thermal growth). Here we tested this concept in nanocrystalline zirconia doped with lanthanum. Although the dopant is observed to segregate to the grain boundaries, causing grain boundary energy decrease and promoting dragging forces for thermally activated boundary movement, irradiation induced grain growth could not be avoided under heavy ion irradiation, suggesting a different growth mechanism as compared to thermal growth. Furthermore, it is apparent that reducing the grain boundary energy reduced the effectiveness of the grain boundary as sinks, and the number of defects in the doped material is higher than in undoped (La-free) YSZ. PMID:27282392

  8. On the interaction of solutes with grain boundaries

    SciTech Connect

    Dingreville, Remi Philippe Michel; Berbenni, Stephane

    2015-11-01

    Solute segregation to grain boundaries is considered by modeling solute atoms as misfitting inclusions within a disclination structural unit model describing the grain boundary structure and its intrinsic stress field. The solute distribution around grain boundaries is described through Fermi–Dirac statistics of site occupancy. The susceptibility of hydrogen segregation to symmetric tilt grain boundaries is discussed in terms of the misorientation angle, the defect type characteristics at the grain boundary, temperature, and the prescribed bulk hydrogen fraction of occupied sites. Through this formalism, it is found that hydrogen trapping on grain boundaries clearly correlates with the grain boundary structure (i.e. type of structural unit composing the grain boundary), and the associated grain boundary misorientation. Specifically, for symmetric tilt grain boundaries about the [001] axis, grain boundaries composed of both B and C structural units show a lower segregation susceptibility than other grain boundaries. A direct correlation between the segregation susceptibility and the intrinsic net defect density is provided through the Frank–Bilby formalism. Moreover, the present formulation could prove to be a simple and useful model to identify classes of grain boundaries relevant to grain boundary engineering.

  9. On the interaction of solutes with grain boundaries

    DOE PAGES

    Dingreville, Remi Philippe Michel; Berbenni, Stephane

    2015-11-01

    Solute segregation to grain boundaries is considered by modeling solute atoms as misfitting inclusions within a disclination structural unit model describing the grain boundary structure and its intrinsic stress field. The solute distribution around grain boundaries is described through Fermi–Dirac statistics of site occupancy. The susceptibility of hydrogen segregation to symmetric tilt grain boundaries is discussed in terms of the misorientation angle, the defect type characteristics at the grain boundary, temperature, and the prescribed bulk hydrogen fraction of occupied sites. Through this formalism, it is found that hydrogen trapping on grain boundaries clearly correlates with the grain boundary structure (i.e.more » type of structural unit composing the grain boundary), and the associated grain boundary misorientation. Specifically, for symmetric tilt grain boundaries about the [001] axis, grain boundaries composed of both B and C structural units show a lower segregation susceptibility than other grain boundaries. A direct correlation between the segregation susceptibility and the intrinsic net defect density is provided through the Frank–Bilby formalism. Moreover, the present formulation could prove to be a simple and useful model to identify classes of grain boundaries relevant to grain boundary engineering.« less

  10. AN ATMOSPHERIC STRUCTURE EQUATION FOR GRAIN GROWTH

    SciTech Connect

    Ormel, C.W.

    2014-07-01

    We present a method to include the evolution of the grain size and grain opacity κ{sub gr} in the equations describing the structure of protoplanetary atmospheres. The key assumption of this method is that a single grain size dominates the grain size distribution at any height r. In addition to following grain growth, the method accounts for mass deposition by planetesimals and grain porosity. We illustrate this method by computation of a simplified atmosphere structure model. In agreement with previous works, grain coagulation is seen to be very efficient. The opacity drops to values much below the often-used ''interstellar medium opacities'' (∼1 cm{sup 2} g{sup –1}) and the atmosphere structure profiles for temperature and density resemble that of the grain-free case. Deposition of planetesimals in the radiative part of the atmosphere hardly influences this outcome as the added surface is quickly coagulated away. We observe a modest dependence on the internal structure (porosity), but show that filling factors cannot become too large because of compression by gas drag.

  11. Effects of watershed densities of animal feeding operations on nutrient concentrations and estrogenic activity in agricultural streams.

    PubMed

    Ciparis, Serena; Iwanowicz, Luke R; Voshell, J Reese

    2012-01-01

    Application of manures from animal feeding operations (AFOs) as fertilizer on agricultural land can introduce nutrients and hormones (e.g. estrogens) to streams. A landscape-scale study was conducted in the Shenandoah River watershed (Virginia, USA) in order to assess the relationship between densities of AFOs in watersheds of agricultural streams and in-stream nutrient concentrations and estrogenic activity. The effect of wastewater treatment plants (WWTPs) on nutrients and estrogenic activity was also evaluated. During periods of high and low flow, dissolved inorganic nitrogen (DIN) and orthophosphate (PO(4)-P) concentrations were analyzed and estrogens/estrogenic compounds were extracted and quantified as17β-estradiol equivalents (E2Eq) using a bioluminescent yeast estrogen screen. Estrogenic activity was measurable in the majority of collected samples, and 20% had E2Eq concentrations >1 ng/L. Relatively high concentrations of DIN (>1000 μg/L) were also frequently detected. During all sampling periods, there were strong relationships between watershed densities of AFOs and in-stream concentrations of DIN (R(2) = 0.56-0.81) and E2Eq (R(2) = 0.39-0.75). Relationships between watershed densities of AFOs and PO(4)-P were weaker, but were also significant (R(2) = 0.27-0.57). When combined with the effect of watershed AFO density, streams receiving WWTP effluent had higher concentrations of PO(4)-P than streams without WWTP discharges, and PO(4)-P was the only analyte with a consistent relationship to WWTPs. The results of this study suggest that as the watershed density of AFOs increases, there is a proportional increase in the potential for nonpoint source pollution of agricultural streams and their receiving waters by nutrients, particularly DIN, and compounds that can cause endocrine disruption in aquatic organisms.

  12. Effects of watershed densities of animal feeding operations on nutrient concentrations and estrogenic activity in agricultural streams

    USGS Publications Warehouse

    Ciparis, S.; Iwanowicz, L.R.; Voshell, J.R.

    2012-01-01

    Application of manures from animal feeding operations (AFOs) as fertilizer on agricultural land can introduce nutrients and hormones (e.g. estrogens) to streams. A landscape-scale study was conducted in the Shenandoah River watershed (Virginia, USA) in order to assess the relationship between densities of AFOs in watersheds of agricultural streams and in-stream nutrient concentrations and estrogenic activity. The effect of wastewater treatment plants (WWTPs) on nutrients and estrogenic activity was also evaluated. During periods of high and low flow, dissolved inorganic nitrogen (DIN) and orthophosphate (PO 4-P) concentrations were analyzed and estrogens/estrogenic compounds were extracted and quantified as17??-estradiol equivalents (E2Eq) using a bioluminescent yeast estrogen screen. Estrogenic activity was measurable in the majority of collected samples, and 20% had E2Eq concentrations >1ng/L. Relatively high concentrations of DIN (>1000??g/L) were also frequently detected. During all sampling periods, there were strong relationships between watershed densities of AFOs and in-stream concentrations of DIN (R 2=0.56-0.81) and E2Eq (R 2=0.39-0.75). Relationships between watershed densities of AFOs and PO 4-P were weaker, but were also significant (R 2=0.27-0.57). When combined with the effect of watershed AFO density, streams receiving WWTP effluent had higher concentrations of PO 4-P than streams without WWTP discharges, and PO 4-P was the only analyte with a consistent relationship to WWTPs. The results of this study suggest that as the watershed density of AFOs increases, there is a proportional increase in the potential for nonpoint source pollution of agricultural streams and their receiving waters by nutrients, particularly DIN, and compounds that can cause endocrine disruption in aquatic organisms. ?? 2011 Elsevier B.V.

  13. Effects of watershed densities of animal feeding operations on nutrient concentrations and estrogenic activity in agricultural streams

    USGS Publications Warehouse

    Ciparis, Serena; Iwanowicz, Luke R.; Voshell, J. Reese

    2012-01-01

    Application of manures from animal feeding operations (AFOs) as fertilizer on agricultural land can introduce nutrients and hormones (e.g. estrogens) to streams. A landscape-scale study was conducted in the Shenandoah River watershed (Virginia, USA) in order to assess the relationship between densities of AFOs in watersheds of agricultural streams and in-stream nutrient concentrations and estrogenic activity. The effect of wastewater treatment plants (WWTPs) on nutrients and estrogenic activity was also evaluated. During periods of high and low flow, dissolved inorganic nitrogen (DIN) and orthophosphate (PO4-P) concentrations were analyzed and estrogens/estrogenic compounds were extracted and quantified as17β-estradiol equivalents (E2Eq) using a bioluminescent yeast estrogen screen. Estrogenic activity was measurable in the majority of collected samples, and 20% had E2Eq concentrations > 1 ng/L. Relatively high concentrations of DIN (> 1000 μg/L) were also frequently detected. During all sampling periods, there were strong relationships between watershed densities of AFOs and in-stream concentrations of DIN (R2 = 0.56–0.81) and E2Eq (R2 = 0.39–0.75). Relationships between watershed densities of AFOs and PO4-P were weaker, but were also significant (R2 = 0.27–0.57). When combined with the effect of watershed AFO density, streams receiving WWTP effluent had higher concentrations of PO4-P than streams without WWTP discharges, and PO4-P was the only analyte with a consistent relationship to WWTPs. The results of this study suggest that as the watershed density of AFOs increases, there is a proportional increase in the potential for nonpoint source pollution of agricultural streams and their receiving waters by nutrients, particularly DIN, and compounds that can cause endocrine disruption in aquatic organisms.

  14. Density Functional Study of the Structure, Stability and Oxygen Reduction Activity of Ultrathin Platinum Nanowires

    SciTech Connect

    Matanovic, Ivana; Kent, Paul; Garzon, Fernando; Henson, Neil J.

    2013-03-14

    We used density functional theory to study the difference in the structure, stability and catalytic reactivity between ultrathin, 0.5–1.0 nm diameter, platinum nanotubes and nanowires. Model nanowires were formed by inserting an inner chain of platinum atoms in small diameter nanotubes. In this way more stable, non-hollow structures were formed. The difference in the electronic structure of platinum nanotubes and nanowires was examined by inspecting the density of surface states and band structure. Furthermore, reactivity toward the oxygen reduction reaction of platinum nanowires was assessed by studying the change in the chemisorption energies of oxygen, hydroxyl, and hydroperoxyl groups, induced by converting the nanotube models to nanowires. Both ultrathin platinum nanotubes and nanowires show distinct properties compared to bulk platinum. Single-wall nanotubes and platinum nanowires with diameters larger than 1 nm show promise for use as oxygen reduction catalysts.

  15. Fumonisin B1, a mycotoxin contaminant of cereal grains, and inducer of apoptosis via the tumour necrosis factor pathway and caspase activation.

    PubMed

    Ciacci-Zanella, J R; Jones, C

    1999-07-01

    Fumonisins are mycotoxins produced by Fusarium moniliforme, a prevalent fungus which infects corn or other cereal grains. Fumonisin B1 (FB1) is the most common mycotoxin produced by F. moniliforme, suggesting that it has toxicological significance. The structure of FB1 resembles sphingoid bases and it inhibits ceramide synthase. As sphingoid bases regulate cell growth, differentiation, transformation and apoptosis, it is reasonable to hypothesize that FB1 can also regulate these activities. Previous studies concluded that FB1 induced apoptosis or cell-cycle arrest in CV-1 cells (African green monkey kidney fibroblasts). In this study, we have identified genes that inhibit FB1-induced apoptosis in CV-1 cells and in two primary human cell types (lung fibroblasts and neonatal kidney cells). A baculovirus gene. inhibitor of apoptosis (IAP), protected CV-1 and the human cells from apoptosis. IAP blocks apoptosis which is induced by the tumour necrosis factor (TNF) pathway. Inhibition of interleukin converting enzymes (ICE proteases or caspases) by the baculovirus gene p35 also inhibited FB1-induced apoptosis. FB1 treatment led to cleavage of Rb (retinoblastoma protein) at its C-terminus in CV-1 or human lung cells. As the C-terminus of Rb is cleaved by ICE proteases during apoptosis, this supports an active role for ICE proteases in FB1-induced apoptosis. The tumour suppressor gene p53 was not required for FB1-induced apoptosis because p53-/- primary mouse embryo fibroblasts underwent apoptosis following FB1 treatment. Furthermore, Bcl-2 was not an effective inhibitor of FB1-induced apoptosis in CV-1 or IMR-90 cells. In summary, these results demonstrate that the TNF pathway and caspases plays an important role in FB1-induced apoptosis.

  16. Activated carbons derived from coconut shells as high energy density cathode material for Li-ion capacitors

    NASA Astrophysics Data System (ADS)

    Jain, Akshay; Aravindan, Vanchiappan; Jayaraman, Sundaramurthy; Kumar, Palaniswamy Suresh; Balasubramanian, Rajasekhar; Ramakrishna, Seeram; Madhavi, Srinivasan; Srinivasan, M. P.

    2013-10-01

    In this manuscript, a dramatic increase in the energy density of ~ 69 Wh kg-1 and an extraordinary cycleability ~ 2000 cycles of the Li-ion hybrid electrochemical capacitors (Li-HEC) is achieved by employing tailored activated carbon (AC) of ~ 60% mesoporosity derived from coconut shells (CS). The AC is obtained by both physical and chemical hydrothermal carbonization activation process, and compared to the commercial AC powders (CAC) in terms of the supercapacitance performance in single electrode configuration vs. Li. The Li-HEC is fabricated with commercially available Li4Ti5O12 anode and the coconut shell derived AC as cathode in non-aqueous medium. The present research provides a new routine for the development of high energy density Li-HEC that employs a mesoporous carbonaceous electrode derived from bio-mass precursors.

  17. Activated carbons derived from coconut shells as high energy density cathode material for Li-ion capacitors

    PubMed Central

    Jain, Akshay; Aravindan, Vanchiappan; Jayaraman, Sundaramurthy; Kumar, Palaniswamy Suresh; Balasubramanian, Rajasekhar; Ramakrishna, Seeram; Madhavi, Srinivasan; Srinivasan, M. P.

    2013-01-01

    In this manuscript, a dramatic increase in the energy density of ~ 69 Wh kg−1 and an extraordinary cycleability ~ 2000 cycles of the Li-ion hybrid electrochemical capacitors (Li-HEC) is achieved by employing tailored activated carbon (AC) of ~ 60% mesoporosity derived from coconut shells (CS). The AC is obtained by both physical and chemical hydrothermal carbonization activation process, and compared to the commercial AC powders (CAC) in terms of the supercapacitance performance in single electrode configuration vs. Li. The Li-HEC is fabricated with commercially available Li4Ti5O12 anode and the coconut shell derived AC as cathode in non-aqueous medium. The present research provides a new routine for the development of high energy density Li-HEC that employs a mesoporous carbonaceous electrode derived from bio-mass precursors. PMID:24141527

  18. Activated carbons derived from coconut shells as high energy density cathode material for Li-ion capacitors.

    PubMed

    Jain, Akshay; Aravindan, Vanchiappan; Jayaraman, Sundaramurthy; Kumar, Palaniswamy Suresh; Balasubramanian, Rajasekhar; Ramakrishna, Seeram; Madhavi, Srinivasan; Srinivasan, M P

    2013-10-21

    In this manuscript, a dramatic increase in the energy density of ~ 69 Wh kg⁻¹ and an extraordinary cycleability ~ 2000 cycles of the Li-ion hybrid electrochemical capacitors (Li-HEC) is achieved by employing tailored activated carbon (AC) of ~ 60% mesoporosity derived from coconut shells (CS). The AC is obtained by both physical and chemical hydrothermal carbonization activation process, and compared to the commercial AC powders (CAC) in terms of the supercapacitance performance in single electrode configuration vs. Li. The Li-HEC is fabricated with commercially available Li₄Ti₅O₁₂ anode and the coconut shell derived AC as cathode in non-aqueous medium. The present research provides a new routine for the development of high energy density Li-HEC that employs a mesoporous carbonaceous electrode derived from bio-mass precursors.

  19. Photoionized Models of Active Galactic Nuclei : Computional Methods and the Problem of high Column Density Models

    NASA Astrophysics Data System (ADS)

    Collin-Souffrin, S.

    Collin-Souffrin and Dumont (1985) have developped a photoionized code using an exact transfer treatment of line and continuum radiation, particularly adapted to clouds of large column densities which are optically thick in the Balmer and Paschen continuum. With this code it is possible to compare various approximations used in previous works to exact computations, and to suggest the most valuable methods. The author gives a few examples of such comparisons.

  20. Study of the process of dust grain discharging in the afterglow of an RF discharge

    SciTech Connect

    Filatova, I. I.; Trukhachev, F. M.; Chubrik, N. I.

    2011-12-15

    The process of decay of dust structures formed of polydisperse grains injected into an RF discharge is investigated. The dust grain velocities after switching-off of the discharge are measured. The number density, dimensions, and residual charges of dust grains are estimated from the balance of forces acting on the grains after discharge is switched off.

  1. TEM Analyses of Itokawa Regolith Grains and Lunar Soil Grains to Directly Determine Space Weathering Rates on Airless Bodies

    NASA Technical Reports Server (NTRS)

    Berger, Eve L.; Keller, Lindsay P.; Christoffersen, Roy

    2016-01-01

    Samples returned from the moon and Asteroid Itokawa by NASA's Apollo Missions and JAXA's Hayabusa Mission, respectively, provide a unique record of their interaction with the space environment. Space weathering effects result from micrometeorite impact activity and interactions with the solar wind. While the effects of solar wind interactions, ion implantation and solar flare particle track accumulation, have been studied extensively, the rate at which these effects accumulate in samples on airless bodies has not been conclusively determined. Results of numerical modeling and experimental simulations do not converge with observations from natural samples. We measured track densities and rim thicknesses of three olivine grains from Itokawa and multiple olivine and anorthite grains from lunar soils of varying exposure ages. Samples were prepared for analysis using a Leica EM UC6 ultramicrotome and an FEI Quanta 3D dual beam focused ion beam scanning electron microscope (FIB-SEM). Transmission electron microscope (TEM) analyses were performed on the JEOL 2500SE 200kV field emission STEM. The solar wind damaged rims on lunar anorthite grains are amorphous, lack inclusions, and are compositionally similar to the host grain. The rim width increases as a smooth function of exposure age until it levels off at approximately 180 nm after approximately 20 My (Fig. 1). While solar wind ion damage can only accumulate while the grain is in a direct line of sight to the Sun, solar flare particles can penetrate to mm-depths. To assess whether the track density accurately predicts surface exposure, we measured the rim width and track density in olivine and anorthite from the surface of rock 64455, which was never buried and has a surface exposure age of 2 My based on isotopic measurements. The rim width from 64455 (60-70nm) plots within error of the well-defined trend for solar wind amorphized rims in Fig. 1. Measured solar flare track densities are accurately reflecting the

  2. Stability of Small Grains in HII Regions and Reflection Nebulae

    NASA Technical Reports Server (NTRS)

    Werner, M. W.; Gauthier, T. N., III; Cawlfield, T.

    1993-01-01

    We have analyzed IRAS data to assess the relative amounts of small and large grains in HII regions and reflection nebulae. Our most important finding is that no evidence for small grain destruction is seen in reflection nebulae, even for [high] values of the radiation energy density at which significant grain destruction apparently occurs in HII regions. This suggests that it is not only the total radiant energy density but also the energy per photon which determines the stability of small grains in astrophysical environments.

  3. Research on electronic states at silicon grain boundaries

    NASA Astrophysics Data System (ADS)

    Werner, J. H.

    1983-02-01

    Electronic states at grain boundaries in artificially grown, boron-doped silicon bicrystals are investigated. The dependence of conductivity and capacitance on temperature, photon energy and density, and frequency of the applied alternating voltage are discussed and quantitatively analyzed. The measurements show that the current transport though the grain boundary is controlled by thermal emission from holes over the grain boundary potential barrier. A formal expression is given for the occupation of interface states in stationary disequilibrium. Measurements of the photoconductivity and photocapacity as a function of light wavelength and intensity are analyzed, and a new spectroscopic method for determining the state density at the grain boundary is developed.

  4. Host density and human activities mediate increased parasite prevalence and richness in primates threatened by habitat loss and fragmentation.

    PubMed

    Mbora, David N M; McPeek, Mark A

    2009-01-01

    1. Habitat loss and fragmentation are the principal causes of the loss of biological diversity. In addition, parasitic diseases are an emerging threat to many animals. Nevertheless, relatively few studies have tested how habitat loss and fragmentation influence the prevalence and richness of parasites in animals. 2. Several studies of nonhuman primates have shown that measures of human activity and forest fragmentation correlate with parasitism in primates. However, these studies have not tested for the ecological mechanism(s) by which human activities or forest fragmentation influence the prevalence and richness of parasites. 3. We tested the hypothesis that increased host density due to forest fragmentation and loss mediates increases in the prevalence and richness of gastrointestinal parasites in two forest primates, the Tana River red colobus (Procolobus rufomitratus, Peters 1879) and mangabey (Cercocebus galeritus galeritus, Peters 1879). We focused on population density because epidemiological theory states that host density is a key determinant of the prevalence and richness of directly transmitted parasites in animals. 4. The Tana River red colobus and mangabey are endemic to a highly fragmented forest ecosystem in eastern Kenya where habitat changes are caused by a growing human population increasingly dependent on forest resources and on clearing forest for cultivation. 5. We found that the prevalence of parasites in the two monkeys was very high compared to primates elsewhere. Density of monkeys was positively associated with forest area and disturbance in forests. In turn, the prevalence and richness of parasites was significantly associated with monkey density, and attributes indicative of human disturbance in forests. 6. We also found significant differences in the patterns of parasitism between the colobus and the mangabey possibly attributable to differences in their behavioural ecology. Colobus are arboreal folivores while mangabeys are terrestrial

  5. Study of the spacecraft potential under active control and plasma density estimates during the MMS commissioning phase

    NASA Astrophysics Data System (ADS)

    Andriopoulou, M.; Nakamura, R.; Torkar, K.; Baumjohann, W.; Torbert, R. B.; Lindqvist, P.-A.; Khotyaintsev, Y. V.; Dorelli, J.; Burch, J. L.; Russell, C. T.

    2016-05-01

    Each spacecraft of the recently launched magnetospheric multiscale MMS mission is equipped with Active Spacecraft Potential Control (ASPOC) instruments, which control the spacecraft potential in order to reduce spacecraft charging effects. ASPOC typically reduces the spacecraft potential to a few volts. On several occasions during the commissioning phase of the mission, the ASPOC instruments were operating only on one spacecraft at a time. Taking advantage of such intervals, we derive photoelectron curves and also perform reconstructions of the uncontrolled spacecraft potential for the spacecraft with active control and estimate the electron plasma density during those periods. We also establish the criteria under which our methods can be applied.

  6. Noncovalent intermolecular interactions between dehydroepiandrosterone and the active site of human dehydroepiandrosterone sulphotransferase: A density functional theory based treatment

    NASA Astrophysics Data System (ADS)

    Astani, Elahe; Heshmati, Emran; Chen, Chun-Jung; Hadipour, Nasser L.; Shekarsaraei, Setareh

    2016-04-01

    A theoretical study was performed to characterize noncovalent intermolecular interactions, especially hydrogen bond (HB), in the active site of enzyme human dehydroepiandrosterone sulphotransferase (SULT2A1/DHEA) using the local (M06-L) and hybrid (M06, M06-2X) meta-GGA functionals of density functional theory (DFT). Results revealed that DHEA is able to form HBs with residues His99, Tyr231, Met137 and Met16 in the active site of the SULT2A1/DHEA. It was found that DHEA interacts with the other residues through electrostatic and Van der Waals interactions.

  7. Microstructural changes in Beta-silicon nitride grains upon crystallizing the grain-boundary glass

    NASA Technical Reports Server (NTRS)

    Lee, William E.; Hilmas, Gregory E.; Lange, F. F. (Editor)

    1991-01-01

    Crystallizing the grain boundary glass of a liquid phase sintered Si3N4 ceramic for 2 h or less at 1500 C led to formation of gamma Y2Si2O7. After 5 h at 1500 C, the gamma Y2Si2O7 had transformed to beta Y2Si2O7 with a concurrent dramatic increase in dislocation density within beta Si3N4 grains. Reasons for the increased dislocation density is discussed. Annealing for 20 h at 1500 C reduced dislocation densities to the levels found in as-sintered materials.

  8. Colony density and activity times of the ant Camponotus semitestaceus (hymenoptera:formicidae) in a shrub steppe community

    SciTech Connect

    Gano, K.A.; Rogers, L.E.

    1983-11-01

    Colony densities and above-ground activity periods were determined for Camponotus semitestaceus colonies within a shrub-steppe community. Colony densities (x +/- SD) averaged 0.088 +/- 0.032 per m/sup 2/ and 0.048 +/- 0.028 per m/sup 2/ on two sagebrush-bunchgrass sites and 0.028 +/- 0.028 per m/sup 2/ on a burned site. Seventy-five percent of the nest entrances were located alongside the stems of sagebrush, indicating a preference for these microhabitats as nest locations. Above-ground activity times were determined by using time lapse photography. Activity commenced shortly after sunset, when light intensities dropped to 2.5 to 1.0 foot-candles (ca. 27 to 11 lux) and terminated just before sunrise. Light intensity appears to be the primary cue for controlling above-ground activity periods of this species, but temperature also appears to be an important factor. When soil surface temperatures drop to 1.7 to 3.9/sup 0/C, all above-ground activity ceases, irrespective of light intensity. 19 references, 3 figures, 2 tables.

  9. Colony density and activity times of the ant Camponotus semitestaceus (hymenoptera: Formicidae) in a shrub steppe community

    SciTech Connect

    Gano, K.A.; Rogers, L.E.

    1983-11-01

    Colony densities and above-ground activity periods were determined for Camponotus semitestaceus colonies within a shrub-steppe community. Colony densities (anti x=/- SD) averaged 0.088 +/- 0.032 per m/sup 2/ and 0.048 +/- 0.028 per m/sup 2/ on two sagebrush-bunchgrass sites and 0.028 +/- 0.028 per m/sup 2/ on a burned site. Seventy-five percent of the nest entrances were located alongside the stems of sagebrush, indicating a preference for these microhabitats as nest locations. Above-ground activity times were determined by using time lapse photography. Activity commenced shortly after sunset, when light intensities dropped to 2.5 to 1.0 foot-candles (ca. 27 to 11 lux) and terminated just before sunrise. Light intensity appears to be the primary cue for controlling above-ground activity periods of this species, but temperature also appears to be an important factor. When soil surface temperatures drop to 1.7 to 3.9/sup 0/C, all above-ground activity ceases, irrespective of light intensity.

  10. Conformable actively multiplexed high-density surface electrode array for brain interfacing

    DOEpatents

    Rogers, John; Kim, Dae-Hyeong; Litt, Brian; Viventi, Jonathan

    2015-01-13

    Provided are methods and devices for interfacing with brain tissue, specifically for monitoring and/or actuation of spatio-temporal electrical waveforms. The device is conformable having a high electrode density and high spatial and temporal resolution. A conformable substrate supports a conformable electronic circuit and a barrier layer. Electrodes are positioned to provide electrical contact with a brain tissue. A controller monitors or actuates the electrodes, thereby interfacing with the brain tissue. In an aspect, methods are provided to monitor or actuate spatio-temporal electrical waveform over large brain surface areas by any of the devices disclosed herein.

  11. A Simple Activity to Facilitate Proportional Reasoning in the Contexts of Density, Dissolving, and Nanoparticles

    ERIC Educational Resources Information Center

    Hamed, Kastro

    2008-01-01

    To address the confusion resulting from difficulties with proportional reasoning among preservice physical science students, a cube-assembly activity was used to bring a sense of concreteness to abstract ideas. The activity took students from the concrete step of assembling cubes of various sizes and directly measuring their properties to slightly…

  12. [Density, size structure and reproductive activity of the pink conch Eustrombus gigas (Mesogastropoda: Strombidae) in Banco Chinchorro, Mexico].

    PubMed

    Cala, Yuself R; Navarrete, Alberto de Jesús; Ocaña, Frank A; Rivera, José Oliva

    2013-12-01

    The pink conch Eustrombus gigas is an important fisheries resource. At the regional level in the Caribbean, over-exploitation and habitat destruction have caused a decrease in the abundance of this resource. In order to provide necessary information for the species management in Mexico, this work aimed to analyze the total density, adult density, size structure and reproductive behavior of pink conch population at Banco Chinchorro during 2009-2010. Data from three seasons were obtained (rainy, dry and cold fronts periods) in three areas: Norte (North), Centro (Center) and Sur (South). The organisms were separated into two groups: (a) the criteria based upon legal harvest in Mexico: legal size conchs (siphonal length > 200 mm) and illegal size conchs (siphonal length < 200 mm), and (b) the criteria based upon sexual maturity using the 15 mm lip thickness standard: lip < 15 mm as juvenile conch and lip > or = 15 mm as adult conch. Copulation, spawning, egg masses and aggregations were evaluated as reproductive evidences. The highest total density was observed during the dry season with 384ind./ha, and the lowest during the rainy season with 127ind./ha. The highest density was reported at Sur (385ind./ha) and the lowest at Norte (198ind./ ha). The highest adult density was observed during the rainy season (8.33ind./ha), and the lowest occurred in the dry season (6.1 ind./ha). Adult density values were 5.55, 7.05 and 8.33ind./ha for Centro, Sur and Norte areas, respectively. Adult densities were lower than the threshold needed for reproduction, and 42% of the population may be vulnerable to fishing, as they had the minimum size for catch (Lsi 200 mm). Furthermore, only 2.2% of the population reached a Gl > 15 mm as sexual maturity indicator. During the study period, only six evidences of reproductive activity were observed. The smaller densities reported at Banco Chinchorro may cause reproduction events to be almost absent which in turn is sufficient evidence to show

  13. [Density, size structure and reproductive activity of the pink conch Eustrombus gigas (Mesogastropoda: Strombidae) in Banco Chinchorro, Mexico].

    PubMed

    Cala, Yuself R; Navarrete, Alberto de Jesús; Ocaña, Frank A; Rivera, José Oliva

    2013-12-01

    The pink conch Eustrombus gigas is an important fisheries resource. At the regional level in the Caribbean, over-exploitation and habitat destruction have caused a decrease in the abundance of this resource. In order to provide necessary information for the species management in Mexico, this work aimed to analyze the total density, adult density, size structure and reproductive behavior of pink conch population at Banco Chinchorro during 2009-2010. Data from three seasons were obtained (rainy, dry and cold fronts periods) in three areas: Norte (North), Centro (Center) and Sur (South). The organisms were separated into two groups: (a) the criteria based upon legal harvest in Mexico: legal size conchs (siphonal length > 200 mm) and illegal size conchs (siphonal length < 200 mm), and (b) the criteria based upon sexual maturity using the 15 mm lip thickness standard: lip < 15 mm as juvenile conch and lip > or = 15 mm as adult conch. Copulation, spawning, egg masses and aggregations were evaluated as reproductive evidences. The highest total density was observed during the dry season with 384ind./ha, and the lowest during the rainy season with 127ind./ha. The highest density was reported at Sur (385ind./ha) and the lowest at Norte (198ind./ ha). The highest adult density was observed during the rainy season (8.33ind./ha), and the lowest occurred in the dry season (6.1 ind./ha). Adult density values were 5.55, 7.05 and 8.33ind./ha for Centro, Sur and Norte areas, respectively. Adult densities were lower than the threshold needed for reproduction, and 42% of the population may be vulnerable to fishing, as they had the minimum size for catch (Lsi 200 mm). Furthermore, only 2.2% of the population reached a Gl > 15 mm as sexual maturity indicator. During the study period, only six evidences of reproductive activity were observed. The smaller densities reported at Banco Chinchorro may cause reproduction events to be almost absent which in turn is sufficient evidence to show

  14. Inverse current source density method in two dimensions: inferring neural activation from multielectrode recordings.

    PubMed

    Łęski, Szymon; Pettersen, Klas H; Tunstall, Beth; Einevoll, Gaute T; Gigg, John; Wójcik, Daniel K

    2011-12-01

    The recent development of large multielectrode recording arrays has made it affordable for an increasing number of laboratories to record from multiple brain regions simultaneously. The development of analytical tools for array data, however, lags behind these technological advances in hardware. In this paper, we present a method based on forward modeling for estimating current source density from electrophysiological signals recorded on a two-dimensional grid using multi-electrode rectangular arrays. This new method, which we call two-dimensional inverse Current Source Density (iCSD 2D), is based upon and extends our previous one- and three-dimensional techniques. We test several variants of our method, both on surrogate data generated from a collection of Gaussian sources, and on model data from a population of layer 5 neocortical pyramidal neurons. We also apply the method to experimental data from the rat subiculum. The main advantages of the proposed method are the explicit specification of its assumptions, the possibility to include system-specific information as it becomes available, the ability to estimate CSD at the grid boundaries, and lower reconstruction errors when compared to the traditional approach. These features make iCSD 2D a substantial improvement over the approaches used so far and a powerful new tool for the analysis of multielectrode array data. We also provide a free GUI-based MATLAB toolbox to analyze and visualize our test data as well as user datasets.

  15. Origins of GEMS Grains

    NASA Technical Reports Server (NTRS)

    Messenger, S.; Walker, R. M.

    2012-01-01

    Interplanetary dust particles (IDPs) collected in the Earth s stratosphere contain high abundances of submicrometer amorphous silicates known as GEMS grains. From their birth as condensates in the outflows of oxygen-rich evolved stars, processing in interstellar space, and incorporation into disks around new stars, amorphous silicates predominate in most astrophysical environments. Amorphous silicates were a major building block of our Solar System and are prominent in infrared spectra of comets. Anhydrous interplanetary dust particles (IDPs) thought to derive from comets contain abundant amorphous silicates known as GEMS (glass with embedded metal and sulfides) grains. GEMS grains have been proposed to be isotopically and chemically homogenized interstellar amorphous silicate dust. We evaluated this hypothesis through coordinated chemical and isotopic analyses of GEMS grains in a suite of IDPs to constrain their origins. GEMS grains show order of magnitude variations in Mg, Fe, Ca, and S abundances. GEMS grains do not match the average element abundances inferred for ISM dust containing on average, too little Mg, Fe, and Ca, and too much S. GEMS grains have complementary compositions to the crystalline components in IDPs suggesting that they formed from the same reservoir. We did not observe any unequivocal microstructural or chemical evidence that GEMS grains experienced prolonged exposure to radiation. We identified four GEMS grains having O isotopic compositions that point to origins in red giant branch or asymptotic giant branch stars and supernovae. Based on their O isotopic compositions, we estimate that 1-6% of GEMS grains are surviving circumstellar grains. The remaining 94-99% of GEMS grains have O isotopic compositions that are indistinguishable from terrestrial materials and carbonaceous chondrites. These isotopically solar GEMS grains either formed in the Solar System or were completely homogenized in the interstellar medium (ISM). However, the

  16. Topside ionosphere bubbles, seen as He+ density depletions: connection with ESF, vertical plasma drift, thermosphere wind and solar activity

    NASA Astrophysics Data System (ADS)

    Sidorova, Larissa

    He+ density depletions, considered as originating from equatorial plasma bubbles (PB), or as possible fossil bubble signatures, were involved in this study. He+ density depletions were observed during a high solar activity (1978-79, F10.7 200) at the topside ionosphere altitudes deeply inside the plasmasphere (L 1.3-3) (Karpachev and Sidorova, ASR, 2002; Sidorova, ASR, 2004, 2007). It is suggested that the equatorial F region irregularities, their post sunset development, evolution, and decay processes are controlled by the sunset electrodynamics of the equatorial region. The He+ density depletion peculiarities were considered in connection with equatorial F-spread (ESF) and vertical plasma drift. The depletion values as function of local time (evening-night hours) were compared with the vertical plasma drift velocity variations, obtained for the same periods (1978-79, F10.7 200; AE-E, IS radar, Jicamarca). Striking similarity in development dynamics was revealed for the different seasons. The monthly mean PB occurrence probability, plotted in local time versus month, was compared with the similar plots for global ESF occurrence probability, derived from ISS-b data (1978-79). Good seasonal correlation (R=0.6) was obtained. Moreover, the comparison of the regional maps, derived from ground-based ionograms, obtained over Brazilian regions (Abdu et al., ASR, 2000) for period with the similar solar activity (1980-81, F10.7 230), shows very well correlation (R=0.67). It is also suggested, that the PBs, produced by Rayleigh-Taylor (R-T) instability at the bottomside of ionosphere and transported up to the topside ionosphere/plasmasphere, could be strong affected by meridional wind during a generation due to inhibiting the growth of R-T instability and flux tube integrated conductivity. For better understanding competing/complementary roles of thermospheric winds in the development of PBs, seen as He+ density depletions, the evaluation of the possible influence of the

  17. Active mammalian replication origins are associated with a high-density cluster of mCpG dinucleotides.

    PubMed Central

    Rein, T; Zorbas, H; DePamphilis, M L

    1997-01-01

    ori-beta is a well-characterized origin of bidirectional replication (OBR) located approximately 17 kb downstream of the dihydrofolate reductase gene in hamster cell chromosomes. The approximately 2-kb region of ori-beta that exhibits greatest replication initiation activity also contains 12 potential methylation sites in the form of CpG dinucleotides. To ascertain whether DNA methylation might play a role at mammalian replication origins, the methylation status of these sites was examined with bisulfite to chemically distinguish cytosine (C) from 5-methylcytosine (mC). All of the CpGs were methylated, and nine of them were located within 356 bp flanking the minimal OBR, creating a high-density cluster of mCpGs that was approximately 10 times greater than average for human DNA. However, the previously reported densely methylated island in which all cytosines were methylated regardless of their dinucleotide composition was not detected and appeared to be an experimental artifact. A second OBR, located at the 5' end of the RPS14 gene, exhibited a strikingly similar methylation pattern, and the organization of CpG dinucleotides at other mammalian origins revealed the potential for high-density CpG methylation. Moreover, analysis of bromodeoxyuridine-labeled nascent DNA confirmed that active replication origins were methylated. These results suggest that a high-density cluster of mCpG dinucleotides may play a role in either the establishment or the regulation of mammalian replication origins. PMID:8972222

  18. Associations of hepatic and lipoprotein lipase activities with changes in dietary composition and low density lipoprotein subclasses.

    PubMed

    Campos, H; Dreon, D M; Krauss, R M

    1995-03-01

    To test whether lipoprotein lipase or hepatic lipase activities are associated with lipoprotein subclasses, and to assess the effects of dietary manipulations on these associations, enzyme activities were measured in postheparin plasma (75 U heparin/kg) from 43 healthy men who were randomly allocated to a low-fat (24% fat, 60% carbohydrate) and a high-fat (46% fat, 38% carbohydrate) diet for 6 weeks each in a cross-over design. The high-fat diet significantly increased both lipoprotein lipase (+20%, P = 0.02) and hepatic lipase (+8%, P = 0.007) activities. On both diets, hepatic lipase activity was significantly positively correlated (P < 0.01) with plasma apolipoprotein (apo)B concentrations, and with levels of small dense low density lipoprotein (LDL) III, measured by analytic ultracentrifugation as mass of lipoproteins of flotation rate (Sof) 3-5, while lipoprotein lipase activity was inversely associated with levels of LDL III (P < 0.05). Despite the cross-sectional correlations, increased hepatic lipase activity was not significantly correlated with the reduction in LDL III mass observed on the high-fat diet. Rather, changes in hepatic lipase were correlated inversely with changes in small very low density lipoproteins (VLDL) of Sof 20-40, and small intermediate density lipoproteins (VLDL) of Sof 10-16. Moreover, changes in lipoprotein lipase activity were not significantly correlated with changes in small LDL, but were positively associated with changes in small IDL of Sof 10-14, and large LDL I of Sof 7-10. Thus, while increased levels of small dense LDL are associated with a metabolic state characterized by relatively increased hepatic lipase and decreased lipoprotein lipase activity, changes in these enzymes do not appear to be primary determinants of diet-induced changes in levels of this LDL subfraction. On the other hand, increased lipoprotein lipase activity induced by high-fat feeding may contribute to the accumulation in plasma of both large LDL I

  19. Cell Density Sensing Alters TGF-β Signaling in a Cell-Type-Specific Manner, Independent from Hippo Pathway Activation

    PubMed Central

    Nallet-Staub, Flore; Yin, Xueqian; Gilbert, Cristèle; Marsaud, Véronique; Ben Mimoun, Saber; Javelaud, Delphine; Leof, Edward B.; Mauviel, Alain

    2015-01-01

    SUMMARY Cell-cell contacts inhibit cell growth and proliferation in part by activating the Hippo pathway that drives the phosphorylation and nuclear exclusion of the transcriptional coactivators YAP and TAZ. Cell density and Hippo signaling have also been reported to block transforming growth factor β (TGF-β) responses, based on the ability of phospho-YAP/TAZ to sequester TGF-β-activated SMAD complexes in the cytoplasm. Herein, we provide evidence that epithelial cell polarization interferes with TGF-β signaling well upstream and independent of cytoplasmic YAP/TAZ. Rather, polarized basolateral presentation of TGF-β receptors I and II deprives apically delivered TGF-β of access to its receptors. Basolateral ligand delivery nonetheless remains entirely effective to induce TGF-β responses. These data demonstrate that cell-type-specific inhibition of TGF-β signaling by cell density is restricted to polarized epithelial cells and reflects the polarized distribution of TGF-β receptors, which thus affects SMAD activation irrespective of Hippo pathway activation. PMID:25758862

  20. Large-Scale Variational Two-Electron Reduced-Density-Matrix-Driven Complete Active Space Self-Consistent Field Methods.

    PubMed

    Fosso-Tande, Jacob; Nguyen, Truong-Son; Gidofalvi, Gergely; DePrince, A Eugene

    2016-05-10

    A large-scale implementation of the complete active space self-consistent field (CASSCF) method is presented. The active space is described using the variational two-electron reduced-density-matrix (v2RDM) approach, and the algorithm is applicable to much larger active spaces than can be treated using configuration-interaction-driven methods. Density fitting or Cholesky decomposition approximations to the electron repulsion integral tensor allow for the simultaneous optimization of large numbers of external orbitals. We have tested the implementation by evaluating singlet-triplet energy gaps in the linear polyacene series and two dinitrene biradical compounds. For the acene series, we report computations that involve active spaces consisting of as many as 50 electrons in 50 orbitals and the simultaneous optimization of 1892 orbitals. For the dinitrene compounds, we find that the singlet-triplet gaps obtained from v2RDM-driven CASSCF with partial three-electron N-representability conditions agree with those obtained from configuration-interaction-driven approaches to within one-third of 1 kcal mol(-1). When enforcing only the two-electron N-representability conditions, v2RDM-driven CASSCF yields less accurate singlet-triplet energy gaps in these systems, but the quality of the results is still far superior to those obtained from standard single-reference approaches. PMID:27065086

  1. Quasiclassical coarse graining and thermodynamic entropy

    SciTech Connect

    Gell-Mann, Murray; Hartle, James B.

    2007-08-15

    Our everyday descriptions of the universe are highly coarse grained, following only a tiny fraction of the variables necessary for a perfectly fine-grained description. Coarse graining in classical physics is made natural by our limited powers of observation and computation. But in the modern quantum mechanics of closed systems, some measure of coarse graining is inescapable because there are no nontrivial, probabilistic, fine-grained descriptions. This essay explores the consequences of that fact. Quantum theory allows for various coarse-grained descriptions, some of which are mutually incompatible. For most purposes, however, we are interested in the small subset of 'quasiclassical descriptions' defined by ranges of values of averages over small volumes of densities of conserved quantities such as energy and momentum and approximately conserved quantities such as baryon number. The near-conservation of these quasiclassical quantities results in approximate decoherence, predictability, and local equilibrium, leading to closed sets of equations of motion. In any description, information is sacrificed through the coarse graining that yields decoherence and gives rise to probabilities for histories. In quasiclassical descriptions, further information is sacrificed in exhibiting the emergent regularities summarized by classical equations of motion. An appropriate entropy measures the loss of information. For a 'quasiclassical realm' this is connected with the usual thermodynamic entropy as obtained from statistical mechanics. It was low for the initial state of our universe and has been increasing since.

  2. Neighbourhood food and physical activity environments in England, UK: does ethnic density matter?

    PubMed Central

    2012-01-01

    Background In England, obesity is more common in some ethnic minority groups than in Whites. This study examines the relationship between ethnic concentration and access to fast food outlets, supermarkets and physical activity facilities. Methods Data on ethnic concentration, fast food outlets, supermarkets and physical activity facilities were obtained at the lower super output area (LSOA) (population average of 1500). Poisson multilevel modelling was used to examine the association between own ethnic concentration and facilities, adjusted for area deprivation, urbanicity, population size and clustering of LSOAs within local authority areas. Results There was a higher proportion of ethnic minorities residing in areas classified as most deprived. Fast food outlets and supermarkets were more common and outdoor physical activity facilities were less common in most than least deprived areas. A gradient was not observed for the relationship between indoor physical activity facilities and area deprivation quintiles. In contrast to White British, increasing ethnic minority concentration was associated with increasing rates of fast food outlets. Rate ratios comparing rates of fast food outlets in high with those in low level of ethnic concentration ranged between 1.28, 95% confidence interval 1.06-1.55 (Bangladeshi) and 2.62, 1.46-4.70 (Chinese). Similar to White British, however, increasing ethnic minority concentration was associated with increasing rate of supermarkets and indoor physical activity facilities. Outdoor physical activity facilities were less likely to be in high than low ethnic concentration areas for some minority groups. Conclusions Overall, ethnic minority concentration was associated with a mixture of both advantages and disadvantages in the provision of food outlets and physical activity facilities. These issues might contribute to ethnic differences in food choices and engagement in physical activity. PMID:22709527

  3. Oxidized Low-Density Lipoprotein Contributes to Atherogenesis via Co-activation of Macrophages and Mast Cells

    PubMed Central

    Chen, Chong; Khismatullin, Damir B.

    2015-01-01

    Oxidized low-density lipoprotein (OxLDL) is a risk factor for atherosclerosis, due to its role in endothelial dysfunction and foam cell formation. Tissue-resident cells such as macrophages and mast cells release inflammatory mediators upon activation that in turn cause endothelial activation and monocyte adhesion. Two of these mediators are tumor necrosis factor (TNF)-α, produced by macrophages, and histamine, produced by mast cells. Static and microfluidic flow experiments were conducted to determine the number of adherent monocytes on vascular endothelium activated by supernatants of oxLDL-treated macrophages and mast cells or directly by oxLDL. The expression of adhesion molecules on activated endothelial cells and the concentration of TNF-α and histamine in the supernatants were measured by flow cytometry and enzyme-linked immunosorbent assay, respectively. A low dose of oxLDL (8 μg/ml), below the threshold for the clinical presentation of coronary artery disease, was sufficient to activate both macrophages and mast cells and synergistically increase monocyte-endothelium adhesion via released TNF-α and histamine. The direct exposure of endothelial cells to a much higher dose of oxLDL (80 μg/ml) had less effect on monocyte adhesion than the indirect activation via oxLDL-treated macrophages and mast cells. The results of this work indicate that the co-activation of macrophages and mast cells by oxLDL is an important mechanism for the endothelial dysfunction and atherogenesis. The observed synergistic effect suggests that both macrophages and mast cells play a significant role in early stages of atherosclerosis. Allergic patients with a lipid-rich diet may be at high risk for cardiovascular events due to high concentration of low-density lipoprotein and histamine in arterial vessel walls. PMID:25811595

  4. Antioxidative Activity after Rosuvastatin Treatment in Patients with Stable Ischemic Heart Disease and Decreased High Density Lipoprotein Cholesterol

    PubMed Central

    Park, Do-Sim; Park, Hyun Young; Rhee, Sang Jae; Kim, Nam-Ho; Oh, Seok Kyu; Jeong, Jin-Won

    2016-01-01

    Background and Objectives The clinical significance of statin-induced high-density lipoprotein cholesterol (HDL-C) changes is not well known. We investigated whether rosuvastatin-induced HDL-C changes can influence the anti-oxidative action of high-density lipoprotein particle. Subjects and Methods A total of 240 patients with stable ischemic heart disease were studied. Anti-oxidative property was assessed by paraoxonase 1 (PON1) activity. We compared the lipid profile and PON1 activity at baseline and at 8 weeks after rosuvastatin 10 mg treatment. Results Rosuvastatin treatment increased the mean HDL-C concentration by 1.9±9.2 mg/dL (6.4±21.4%). HDL-C increased in 138 patients (57.5%), but decreased in 102 patients (42.5%) after statin treatment. PON1 activity increased to 19.1% in all patients. In both, the patients with increased HDL-C and with decreased HDL-C, PON1 activity significantly increased after rosuvastatin treatment (+19.3% in increased HDL-C responder; p=0.018, +18.8% in decreased HDL-C responder; p=0.045 by paired t-test). Baseline PON1 activity modestly correlated with HDL-C levels (r=0.248, p=0.009); however, the PON1 activity evaluated during the course of the treatment did not correlate with HDL-C levels (r=0.153, p=0.075). Conclusion Rosuvastatin treatment improved the anti-oxidative properties as assessed by PON1 activity, regardless of on-treatment HDL-C levels, in patients with stable ischemic heart disease. PMID:27275167

  5. Dislocation Content Measured Via 3D HR-EBSD Near a Grain Boundary in an AlCu Oligocrystal

    NASA Technical Reports Server (NTRS)

    Ruggles, Timothy; Hochhalter, Jacob; Homer, Eric

    2016-01-01

    Interactions between dislocations and grain boundaries are poorly understood and crucial to mesoscale plasticity modeling. Much of our understanding of dislocation-grain boundary interaction comes from atomistic simulations and TEM studies, both of which are extremely limited in scale. High angular resolution EBSD-based continuum dislocation microscopy provides a way of measuring dislocation activity at length scales and accuracies relevant to crystal plasticity, but it is limited as a two-dimensional technique, meaning the character of the grain boundary and the complete dislocation activity is difficult to recover. However, the commercialization of plasma FIB dual-beam microscopes have made 3D EBSD studies all the more feasible. The objective of this work is to apply high angular resolution cross correlation EBSD to a 3D EBSD data set collected by serial sectioning in a FIB to characterize dislocation interaction with a grain boundary. Three dimensional high angular resolution cross correlation EBSD analysis was applied to an AlCu oligocrystal to measure dislocation densities around a grain boundary. Distortion derivatives associated with the plasma FIB serial sectioning were higher than expected, possibly due to geometric uncertainty between layers. Future work will focus on mitigating the geometric uncertainty and examining more regions of interest along the grain boundary to glean information on dislocation-grain boundary interaction.

  6. Seasonal Activity, Density, and Collection Efficiency of the Blacklegged Tick (Ixodes scapularis) (Acari: Ixodidae) in Mid-Western Pennsylvania.

    PubMed

    Simmons, T W; Shea, J; Myers-Claypole, M A; Kruise, R; Hutchinson, M L

    2015-11-01

    Although Pennsylvania has recently reported the greatest number of Lyme disease cases in the United States, with the largest increase for PA occurring in its western region, the population biology of the blacklegged tick (Ixodes scapularis Say) has not been adequately characterized in western PA. We studied the seasonal activity of host-seeking I. scapularis larvae, nymphs, and adults in mid-western PA over the course of a year, including a severe winter, and determined their absolute densities and collection efficiencies using replicated mark-release-recapture or removal methods. Our results are compared to those from similar studies conducted in the highly Lyme disease endemic Hudson Valley region of southeastern New York State. The seasonal activity of I. scapularis was intermediate between patterns observed in the coastal northeastern and upper Midwestern United States. Only one peak of larval activity was observed, which was later than the major peak in the Midwest, but earlier than in the northeast. Seasonal synchrony of larvae and nymphs was similar to the northeast, but the activity peaks were much closer together, although not completely overlapping as in the Midwest. Pre- and postwinter relative densities of questing adult I. scapularis were not significantly different from one another. The absolute densities and collection efficiencies of larvae, nymphs, and adults were comparable to results from classic research conducted at the Louis Calder Center in Westchester County, NY. We conclude that the population biology of I. scapularis in mid-western PA is similar to southeastern NYS contributing to a high acarological Lyme disease risk. PMID:26336271

  7. Neuromagnetic evidence for the timing of lexical activation: an MEG component sensitive to phonotactic probability but not to neighborhood density.

    PubMed

    Pylkkänen, Liina; Stringfellow, Andrew; Marantz, Alec

    2002-01-01

    Evidence from electrophysiological measures such as ERPs (event-related potentials) and MEG (magnetoencephalography) suggest that the first evoked brain response component sensitive to stimulus properties affecting reaction times in word recognition tasks occurs at 300-400 ms. The present study used the stimulus manipulation of Vitevich and Luce (1999) to investigate whether the M350, an MEG response component peaking at 300-400 ms, reflects lexical or postlexical processing. Stimuli were simultaneously varied in phonotactic probability, which facilitates lexical activation, and in phonological neighborhood density, which inhibits the lexical decision process. The present results indicate that the M350 shows facilitation by phonotactic probability rather than inhibition by neighborhood density. Thus the M350 cannot be a postlexical component. PMID:12081430

  8. Zinc cysteine active sites of metalloproteins: a density functional theory and x-ray absorption fine structure study.

    PubMed

    Dimakis, Nicholas; Farooqi, Mohammed Junaid; Garza, Emily Sofia; Bunker, Grant

    2008-03-21

    Density functional theory (DFT) and x-ray absorption fine structure (XAFS) spectroscopy are complementary tools for the biophysical study of active sites in metalloproteins. DFT is used to compute XAFS multiple scattering Debye Waller factors, which are then employed in genetic algorithm-based fitting process to obtain a global fit to the XAFS in the space of fitting parameters. Zn-Cys sites, which serve important functions as transcriptional switches in Zn finger proteins and matrix metalloproteinases, previously have proven intractable by this method; here these limitations are removed. In this work we evaluate optimal DFT nonlocal functionals and basis sets for determining optimal geometries and vibrational densities of states of mixed ligation Zn(His)(4-n)(Cys)(n) sites. Theoretical results are compared to experimental XAFS measurements and Raman spectra from the literature and tabulated for use.

  9. Interstellar Dust Grain Alignment

    NASA Astrophysics Data System (ADS)

    Andersson, B.-G.; Lazarian, A.; Vaillancourt, John E.

    2015-08-01

    Interstellar polarization at optical-to-infrared wavelengths is known to arise from asymmetric dust grains aligned with the magnetic field. This effect provides a potentially powerful probe of magnetic field structure and strength if the details of the grain alignment can be reliably understood. Theory and observations have recently converged on a quantitative, predictive description of interstellar grain alignment based on radiative processes. The development of a general, analytical model for this radiative alignment torque (RAT) theory has allowed specific, testable predictions for realistic interstellar conditions. We outline the theoretical and observational arguments in favor of RAT alignment, as well as reasons the "classical" paramagnetic alignment mechanism is unlikely to work, except possibly for the very smallest grains. With further detailed characterization of the RAT mechanism, grain alignment and polarimetry promise to not only better constrain the interstellar magnetic field but also provide new information on the dust characteristics.

  10. Influence of the Surface Functional Group Density on the Carbon-Nanotube-Induced α-Chymotrypsin Structure and Activity Alterations.

    PubMed

    Zhao, Xingchen; Hao, Fang; Lu, Dawei; Liu, Wei; Zhou, Qunfang; Jiang, Guibin

    2015-08-26

    Because of the special properties of carbon nanotubes (CNTs), their applications have been introduced to many fields. The biosafety of these emerging materials is of high concern concomitantly. Because CNTs may initially bind with proteins in biofluids before they exert biological effects, it is of great importance to understand how the target proteins interact with these exogenous nanomaterials. Here we investigated the interaction between α-chymotrypsin (α-ChT) and carboxylized multiwalled CNTs in a simulated biophysical environment utilizing the techniques of fluorescence, UV-vis, circular dichroism spectroscopy, ζ potential, atomic force microscopy, and bicinchoninic acid analysis. It was demonstrated that CNTs interacted with α-ChT through electrostatic forces, causing a decrement in the α-helix and an increment in the β-sheet content of the protein. The protein fluorescence was quenched in a static mode. The increase in the surface modification density of CNTs enhanced the protein absorption and decreased the enzymatic activity correspondingly. α-ChT activity inhibition induced by CNTs with low surface modification density exhibited noncompetitive characteristics; however, a competitive feature was observed when CNTs with high surface modification density interacted with the protein. An increase of the ionic strength in the reaction buffer may help to reduce the interaction between CNTs and α-ChT because the high ionic strength may favor the release of the protein from binding on a CNT surface modified with functional groups. Accordingly, the functionalization density on the CNT surface plays an important role in the regulation of their biological effects and is worthy of concern when new modified CNTs are developed.

  11. Activation of intestinal peroxisome proliferator-activated receptor-α increases high-density lipoprotein production

    PubMed Central

    Colin, Sophie; Briand, Olivier; Touche, Véronique; Wouters, Kristiaan; Baron, Morgane; Pattou, François; Hanf, Rémy; Tailleux, Anne; Chinetti, Giulia; Staels, Bart; Lestavel, Sophie

    2013-01-01

    Aims Peroxisome Proliferator-Activated Receptor (PPAR) α is a transcription factor controlling lipid metabolism in liver, heart, muscle and macrophages. PPARα-activation increases plasma HDL-cholesterol and exerts hypotriglyceridemic actions via the liver. However, the intestine expresses PPARα, produces HDL and chylomicrons and is exposed to diet-derived PPARα ligands. Therefore, we examined the effects of PPARα-activation on intestinal lipid and lipoprotein metabolism. Methods and Results The impact of PPARα-activation was evaluated in term of HDL-related gene expression in mice, ex-vivo in human jejunal biopsies and in Caco-2/TC7 cells. ApoAI/HDL secretion, cholesterol esterification and trafficking were also studied in-vitro. In parallel to improving plasma lipid profiles and increasing liver and intestinal expression of fatty-acid-oxidation genes, treatment with the dual PPARα/δ-ligand GFT505 resulted in a more pronounced increase of plasma HDL compared to fenofibrate in mice. GFT505, but not fenofibrate, increased the expression of HDL-production genes such as apolipoprotein-AI and ATP-Binding-Cassette-A1 transporter in murine intestines. A similar increase was observed upon PPARα-activation of human biopsies and Caco-2/TC7 cells. Additionally, HDL secretion by Caco-2/TC7 cells increased. Moreover, PPARα-activation decreased the cholesterol-esterification capacity of Caco-2/TC7 cells, modified cholesterol trafficking and reduced apolipoprotein-B secretion. Conclusions PPARα-activation reduces cholesterol esterification, suppresses chylomicron- and increases HDL-secretion by enterocytes. These results identify the intestine as a target organ of PPARα-ligands with entero-hepatic tropism to reduce atherogenic dyslipidemia. PMID:22843443

  12. Differential influence of physical activity on lumbar spine and femoral neck bone mineral density in the elderly population.

    PubMed

    Vuillemin, A; Guillemin, F; Jouanny, P; Denis, G; Jeandel, C

    2001-06-01

    This study investigates the relationship between lifetime physical activity and bone mineral density (BMD) at various sites in 129 healthy men and women aged 72.1 +/- 6.5 years. BMD was measured by dual energy x-ray absorptiometry, and physical activity was assessed by using the QUANTAP system (Quantification de l'Activité Physique), a standardized and structured computer-assisted interview tool designed to assess lifetime physical activity. Linear regression models controlling for age, gender, height, body mass, lean mass, and smoking habits were performed. Higher levels of sporting activity during youth were associated with greater lumbar spine BMD ( p < .001). Similarly, femoral neck BMD was greatest in subjects who reported regularly taking part in sports over the previous 20 years ( p <. 05) and during their whole lifetime ( p < 0.05). Sporting activity at the time of bone mass development increases subsequent lumbar spine BMD, and more recent sporting activity contributes to the preservation of femoral neck BMD. These results suggest that physical activity has a differential influence on BMD at different sites and at different ages, possibly related to the processes of bone construction and bone aging taking place at the time.

  13. Differential influence of physical activity on lumbar spine and femoral neck bone mineral density in the elderly population.

    PubMed

    Vuillemin, A; Guillemin, F; Jouanny, P; Denis, G; Jeandel, C

    2001-06-01

    This study investigates the relationship between lifetime physical activity and bone mineral density (BMD) at various sites in 129 healthy men and women aged 72.1 +/- 6.5 years. BMD was measured by dual energy x-ray absorptiometry, and physical activity was assessed by using the QUANTAP system (Quantification de l'Activité Physique), a standardized and structured computer-assisted interview tool designed to assess lifetime physical activity. Linear regression models controlling for age, gender, height, body mass, lean mass, and smoking habits were performed. Higher levels of sporting activity during youth were associated with greater lumbar spine BMD ( p < .001). Similarly, femoral neck BMD was greatest in subjects who reported regularly taking part in sports over the previous 20 years ( p <. 05) and during their whole lifetime ( p < 0.05). Sporting activity at the time of bone mass development increases subsequent lumbar spine BMD, and more recent sporting activity contributes to the preservation of femoral neck BMD. These results suggest that physical activity has a differential influence on BMD at different sites and at different ages, possibly related to the processes of bone construction and bone aging taking place at the time. PMID:11382786

  14. The Use of Kernel Density Estimation to Examine Associations between Neighborhood Destination Intensity and Walking and Physical Activity

    PubMed Central

    King, Tania L.; Thornton, Lukar E.; Bentley, Rebecca J.; Kavanagh, Anne M.

    2015-01-01

    Background Local destinations have previously been shown to be associated with higher levels of both physical activity and walking, but little is known about how the distribution of destinations is related to activity. Kernel density estimation is a spatial analysis technique that accounts for the location of features relative to each other. Using kernel density estimation, this study sought to investigate whether individuals who live near destinations (shops and service facilities) that are more intensely distributed rather than dispersed: 1) have higher odds of being sufficiently active; 2) engage in more frequent walking for transport and recreation. Methods The sample consisted of 2349 residents of 50 urban areas in metropolitan Melbourne, Australia. Destinations within these areas were geocoded and kernel density estimates of destination intensity were created using kernels of 400m (meters), 800m and 1200m. Using multilevel logistic regression, the association between destination intensity (classified in quintiles Q1(least)—Q5(most)) and likelihood of: 1) being sufficiently active (compared to insufficiently active); 2) walking≥4/week (at least 4 times per week, compared to walking less), was estimated in models that were adjusted for potential confounders. Results For all kernel distances, there was a significantly greater likelihood of walking≥4/week, among respondents living in areas of greatest destinations intensity compared to areas with least destination intensity: 400m (Q4 OR 1.41 95%CI 1.02–1.96; Q5 OR 1.49 95%CI 1.06–2.09), 800m (Q4 OR 1.55, 95%CI 1.09–2.21; Q5, OR 1.71, 95%CI 1.18–2.48) and 1200m (Q4, OR 1.7, 95%CI 1.18–2.45; Q5, OR 1.86 95%CI 1.28–2.71). There was also evidence of associations between destination intensity and sufficient physical activity, however these associations were markedly attenuated when walking was included in the models. Conclusions This study, conducted within urban Melbourne, found that those who lived

  15. Seasonal Variation in Population Density and Heterotrophic Activity of Attached and Free-Living Bacteria in Coastal Waters

    PubMed Central

    Iriberri, Juan; Unanue, Marian; Barcina, Isabel; Egea, Luis

    1987-01-01

    The abundance and heterotrophic activity of attached and free-living bacteria were examined seasonally in coastal water. Heterotrophic activity was determined by the uptake of [14C]glucose. The density of attached bacteria was always minor, not showing a seasonal variation, whereas the free-living bacteria were more numerous and showed a marked seasonal variation, their density being higher under warmer conditions. The contribution of the attached bacteria to the total assimilation of [14C]glucose (from 10 to 38%) was lower than that of the free-living bacteria, neither of them showing a seasonal variation. On a cellular basis, attached bacteria were more active, since they assimilated more [14C]glucose and showed, under warmer conditions, a higher cellular volume (0.102 versus 0.047 μm3). We consider that the factors responsible for these observations were the amount and quality of the particulate material, the different availability of organic matter for the two types of bacteria, and in a fundamental way, the variation in water temperature. PMID:16347451

  16. Current Activities Assessing Butt Fusion Joint Integrity in High Density Polyethylene Piping

    SciTech Connect

    Crawford, Susan L.; Cinson, Anthony D.; Doctor, Steven R.; Denslow, Kayte M.

    2012-09-01

    The Pacific Northwest National Laboratory (PNNL) in Richland, Washington, conducted initial studies to evaluate the effectiveness of nondestructive examinations (NDE) coupled with mechanical testing for assessing butt fusion joint integrity in high density polyethylene (HDPE) pipe. The work provided insightful information to the United States Nuclear Regulatory Commission (NRC) on the effectiveness of volumetric inspection techniques for detecting lack of fusion (LOF) conditions in the fusion joints. HDPE has been installed on a limited basis in American Society of Mechanical Engineers (ASME) Class 3, buried piping systems at several operating U.S. nuclear power plants and has been proposed for use in new construction. A comparison was made between the results from ultrasonic and microwave nondestructive examinations and the results from mechanical destructive evaluations, specifically the high-speed tensile test and the side-bend test, for determining joint integrity. The data comparison revealed that none of the NDE techniques detected all of the lack-of-fusion conditions that were revealed by the destructive tests. Follow-on work has recently been initiated at PNNL to accurately characterize the NDE responses from machined flaws of varying size and location in PE 4710 materials as well as the LOF condition. This effort is directed at quantifying the ability of volumetric NDE techniques to detect flaws in relation to the critical flaw size associated with joint integrity. A status of these latest investigations is presented.

  17. Source segregation and food waste prevention activities in high-density households in a deprived urban area

    SciTech Connect

    Rispo, A.; Williams, I.D. Shaw, P.J.

    2015-10-15

    Highlights: • Study of waste management in economically and socially deprived high-density housing. • Food waste segregation, prevention and recycling activities investigated. • Study involved a waste audit and household survey of 1034 households. • Populations in such areas are “hard-to-reach”. • Exceptional efforts and additional resources are required to improve performance. - Abstract: A waste audit and a household questionnaire survey were conducted in high-density housing estates in one of the most economically and socially deprived areas of England (Haringey, London). Such areas are under-represented in published research. The study examined source segregation, potential participation in a food waste segregation scheme, and food waste prevention activities in five estates (1034 households). The results showed that: contamination of recyclables containers was low; ca. 28% of the mixed residual waste’s weight was recyclable; food waste comprised a small proportion of the waste from these residents, probably because of their relatively disadvantaged economic circumstances; and the recycling profile reflected an intermittent pattern of behaviour. Although the majority of respondents reported that they would participate in a food waste separation scheme, the response rate was low and many responses of “don’t know” were recorded. Municipalities committed to foster improved diversion from landfill need to recognise that there is no “quick and easy fix”, regardless of local or national aspirations. Lasting and sustained behaviour change requires time and the quality of service provision and associated infrastructure play a fundamental role in facilitating residents to participate effectively in waste management activities that maximise capture of source-segregated materials. Populations in deprived areas that reside in high-rise, high-density dwellings are “hard-to-reach” in terms of participation in recycling schemes and exceptional

  18. Grain boundary behavior in varistor-capacitor TiO2-rich CaCu3Ti4O12 ceramics

    NASA Astrophysics Data System (ADS)

    Lin, Yuan-Hua; Cai, Jingnan; Li, Ming; Nan, Ce-Wen; He, Jinliang

    2008-04-01

    We prepared TiO2-rich CaCu3Ti4O12 (CCTO) ceramics by a solid-state sintering process and observed large nonlinear electrical and high dielectric behaviors. Microstructure and phase composition analyses show that CCTO grain-amorphous/TiO2 nanograin boundary-CCTO grain junction structures exist in these TiO2-rich CCTO ceramics, which leads to the nonlinear electrical and high dielectric properties. The temperature dependence of impedance spectroscopy and relationships between electrical current density versus applied electrical field indicate that the activation energy of the grain boundary for the TiO2-rich CCTO ceramics is almost the same as the potential barrier height and both of them are weakly independent of the doped concentration of TiO2, which supports the internal barrier layer capacitor model of Schottky barriers at the grain boundaries between semiconducting CCTO grains.

  19. Dependence of mobility on density of gap states in organics by GAMEaS-gate modulated activation energy spectroscopy

    NASA Astrophysics Data System (ADS)

    So, Woo-young; Lang, David V.; Butko, Vladimir Y.; Chi, Xiaoliu; Lashley, Jason C.; Ramirez, Arthur P.

    2008-09-01

    We develop a broadly applicable transport-based technique, gate modulated activation energy spectroscopy (GAMEaS), for determining the density of states (DOS) in an energy gap. GAMEaS is applied to field-effect transistors (FETs) made from different single crystal oligomer semiconductors. We find that there are two distinct types of band tails, deep and shallow, depending on the crystallization process. The exponential band tails of the localized DOS are characterized by their slope with the highest mobility FETs having a value of 29 eV-1 close to 1/kBT at 300 K.

  20. Microstructure stability of ultra-fine grained magnesium alloy AZ31 processed by extrusion and equal-channel angular pressing (EX–ECAP)

    SciTech Connect

    Stráská, Jitka; Janeček, Miloš; Čížek, Jakub; Stráský, Josef; Hadzima, Branislav

    2014-08-15

    Thermal stability of the ultra-fine grained (UFG) microstructure of magnesium AZ31 alloy was investigated. UFG microstructure was achieved by a combined two-step severe plastic deformation process: the extrusion (EX) and subsequent equal-channel angular pressing (ECAP). This combined process leads to refined microstructure and enhanced microhardness. Specimens with UFG microstructure were annealed isochronally at temperatures 150–500 °C for 1 h. The evolution of microstructure, mechanical properties and dislocation density was studied by electron backscatter diffraction (EBSD), microhardness measurements and positron annihilation spectroscopy (PAS). The coarsening of the fine-grained structure at higher temperatures was accompanied by a gradual decrease of the microhardness and decrease of dislocation density. Mechanism of grain growth was studied by general equation for grain growth and Arrhenius equation. Activation energies for grain growth were calculated to be 115, 33 and 164 kJ/mol in temperature ranges of 170–210 °C, 210–400 °C and 400–500 °C (443–483 K, 483–673 K and 673–773 K), respectively. - Highlights: • Microhardness of UFG AZ31 alloy decreases with increasing annealing temperature. • This fact has two reasons: dislocation annihilations and/or grain growth. • The activation energies for grain growth were calculated for all temperature ranges.

  1. Tai Chi Chuan exercises in enhancing bone mineral density in active seniors.

    PubMed

    Lui, Pauline Po Yee; Qin, Ling; Chan, Kai Ming

    2008-01-01

    Osteoporosis is a silent, systemic, chronic disease characterized by low bone mass and structural deterioration of bone tissue. Its clinical and public health implications are substantial because of the mortality, morbidity, and medical care cost associated with osteoporotic fractures. Although estrogen-replacement therapy or anti-bone resorptive drugs can prevent postmenopausal bone loss, they also show side effects. Physical activity is an nonpharmacological approach for prevention of osteoporosis. Among different types of physical activities, Tai Chi Chuan (TCC) is a low- to moderate-intensity exercise particularly suitable for the elderly, and has been practiced by Chinese for centuries. This article reviews the benefits of TCC for the prevention of osteoporosis and falls by retarding bone loss, improving neuromuscular coordination, and promoting general health. PMID:18206569

  2. Hydrothermal quartz formation during fluctuations of brittle shear-zone activity and fluid flow: grain growth and deformation structures of the Pfahl shear zone (Germany)

    NASA Astrophysics Data System (ADS)

    Yilmaz, T.; Prosser, G.; Liotta, D.; Kruhl, J. H.

    2012-12-01

    , crosscutting the first generations of fine-grained quartz mass and the wall rocks, in connection to intense fracturing and brecciation. The complex geometry of the vein sets points to multiple fluid injections and brecciation, as additionally indicated by coarse quartz with different inclusion and CL intensity. Temporal changes of strain rate are indicated by crystal plastic deformation structures in quartz, which overprint brittle structures. (iv) The fourth quartz generation occurs in mm- to dm-thick quartz veins, partly open as geodes, filling N-S oriented cm- to dm-spaced fractures that crosscut the earlier quartz masses and veins and extend at least several meters into the wall rock. They indicate the last activity of the shear-zone in a constant kinematic framework. Summarizing, the Pfahl shear zone shows brittle-ductile deformation during the long-term activity of a large-scale hydrothermal system. Consequently, it represents an excellent example where different generations of quartz precipitation can be connected to fluctuations of fluid flow and strain rate.

  3. The solar activity dependence of nonmigrating tides in electron density at low and middle latitudes observed by CHAMP and GRACE

    NASA Astrophysics Data System (ADS)

    Zhou, Yun-Liang; Wang, Li; Xiong, Chao; Lühr, Hermann; Ma, Shu-Ying

    2016-04-01

    In this paper we use more than a decade of in situ electron density observations from CHAMP and GRACE satellites to investigate the solar activity dependence of nonmigrating tides at both low and middle latitudes. The results indicate that the longitudinal patterns of F region electron density vary with season and latitude, which are exhibiting a wavenumber 4 (WN4) pattern around September equinox at low latitudes and WN1/WN2 patterns during local summer at the southern/northern middle latitudes. These wave patterns in the F region ionosphere can clearly be seen during both solar maximum and minimum years. At low latitudes the absolute amplitudes of DE3 (contributing to the WN4 pattern) are found to be highly related to the solar activity, showing larger amplitudes during solar maximum years. Similarly a solar activity dependence can also be found for the absolute amplitudes of D0, DW2 and DE1 (contributing to the WN1 and WN2 pattern) at middle latitudes. The relative amplitudes (normalized by the zonal mean) of these nonmigrating tides at both low and middle altitudes show little dependence on solar activity. We further found a clear modulation by the quasi-biennial oscillation (QBO) of the relative DE3 amplitudes in both satellite observations, which is consistent with the QBO dependence as reported for the E region temperatures and zonal wind. It also supports the strong coupling of the low-latitude nonmigrating tidal activity between the E and F regions. However, the QBO dependence cannot be found for the relative amplitudes of the nonmigrating tides at middle latitudes, which implies that these tides are generated in situ at F region altitudes.

  4. Physical activity benefits bone density and bone-related hormones in adult men with cervical spinal cord injury.

    PubMed

    Chain, Amina; Koury, Josely C; Bezerra, Flávia Fioruci

    2012-09-01

    Severe bone loss is a recognized complication of chronic spinal cord injury (SCI). Physical exercise contributes to bone health; however, its influence on bone mass of cervical SCI individuals has not been investigated. The aim of this study was to investigate the influence of physical activity on bone mass, bone metabolism, and vitamin D status in quadriplegics. Total, lumbar spine (L1-L4), femur and radius bone mineral density (BMD) were assessed in active (n = 15) and sedentary (n = 10) quadriplegic men by dual energy X-ray absorptiometry. Concentrations of 25-hydroxyvitamin D [25(OH)D], PTH, IGF1, osteocalcin and NTx were measured in serum. After adjustments for duration of injury, total body mass, and habitual calcium intake, bone indices were similar between groups, except for L1-L4 BMD Z score that was higher in the sedentary group (P < 0.05). Hours of physical exercise per week correlated positively with 25(OH)D (r = 0.59; P < 0.05) and negatively with PTH (r = -0.50; P < 0.05). Femur BMD was negatively associated with the number of months elapsed between the injury and the onset of physical activity (r = -0.60; P < 0.05). Moreover, in the active subjects, both L1-L4 BMD Z score (r = 0.72; P < 0.01) and radius BMD (r = 0.59; P < 0.05) were positively associated with calcium intake. In this cross-sectional study, both the onset of physical activity after injury and the number of hours dedicated to exercise were able to influence bone density and bone-related hormones in quadriplegic men. Our results also suggest a positive combined effect of exercise and calcium intake on bone health of quadriplegic individuals.

  5. High-density active optical cable: from a new concept to a prototype

    NASA Astrophysics Data System (ADS)

    Wohlfeld, Denis; Lemke, Frank; Froening, Holger; Schenk, Sven; Bruening, Ulrich

    2011-01-01

    Evolution in high performance computing (HPC) leads to increasing demands on bandwidth, connectivity and flexibility. Active optical cables (AOC) are of special interest, combining the benefits of electrical connectors and optical transmission. Optimization and development of AOC solutions requires enhancements concerning different technology barriers. Area and volume occupied by connectors is of special interest within HPC networks. This led to the development of a 12x AOC for the mini-HT connector creating the densest AOC available. In order to integrate electrical optical conversion into a module not higher than 3 mm, a new concept of coupling fibers to VCSELs or photodiodes had to be developed. This unique concept is based on a direct replication process of an integrated fiber coupler consisting of a 90° light deflecting and focusing mirror, a fiber guiding structure, and a fiber funnel. The integrated fiber coupler is directly replicated on top of active components, reducing the distance between active components and fibers to a minimum, thus providing a highly efficient light coupling. As AOC prototype, multi-chipmodules (MCM) including the complete electrical to optical conversion for send and receive connected by two 12x fiber ribbons have been developed. The paper presents the integrated fiber coupling technique and also design and measurement data of the prototype.

  6. What Controls Ooid Grain Size?

    NASA Astrophysics Data System (ADS)

    Trower, L.; Lamb, M. P.; Fischer, W. W.

    2015-12-01

    Ooids are subspherical chemical sand grains composed of concentric layers of CaCO₃ surrounding a central nucleus. These grains represent a common mode of carbonate sedimentation, making them potentially powerful proxies for paleoenvironmental conditions, provided a mechanistic understanding of the physical, chemical, and perhaps biological conditions necessary for their formation. At a basic level, growth of an ooid reflects that precipitation has outpaced abrasion over the ooid's lifetime. We can describe change in ooid size over time (net growth rate) mechanistically as the sum of a growth rate (the rate of carbonate precipitation on the ooid surface) and an abrasion rate (the rate of removal of material through grain-grain and grain-bed collisions). Previous studies have addressed the growth rate, investigating the extent to which microbial activity affects and/or controls carbonate precipitation on ooid surfaces, and the net growth rate, using stepwise acid digestion and radiocarbon dating to determine the ages of cortical layers. We focused on the abrasion rate and designed an experimental study to measure abrasion rates of ooids as a function of grain size and sediment transport stage. Preliminary experiments with medium-sand-sized ooids at a Rouse number of ~1.2 yielded an abrasion rate of 0.04 g/hr (or ~40 ng/ooid/hr), which is four orders of magnitude greater than the fastest net growth rates reported in the recent high resolution ooid cortex radiocarbon dating study by Beaupre et al. (2015). This result requires that either: 1) ooids are essentially not moving and therefore not being abraded or 2) precipitation rates are also much more rapid than the net growth rates estimated by incremental radiocarbon dating. The former constraint is inconsistent with field observations that most marine ooids occur in high energy shoal environments, both in modern examples and in the rock record. Precipitation rates must therefore also be relatively rapid compared

  7. Antioxidant activities of black and yellow soybeans against low density lipoprotein oxidation.

    PubMed

    Takahashi, Rie; Ohmori, Reiko; Kiyose, Chikako; Momiyama, Yukihiko; Ohsuzu, Fumitaka; Kondo, Kazuo

    2005-06-01

    Several studies have demonstrated that the daily intakes of soy foods were associated with a reduced cardiovascular risk. The aim of our study was to investigate the inhibitory effect of black soybeans on low density lipoprotein (LDL) oxidation in comparison to yellow soybeans. The extract from black soybean had a longer LDL oxidation lag time than that from yellow soybean (205 +/- 16 and 65 +/- 3 min, respectively). When both soybeans were divided into the seed coat and the mixture of the germ and cotyledon, the diluted extract solution from the black soybean seed coat prolonged the lag time significantly more than the original extract of the yellow soybean seed coat. On the other hand, antioxidant effects of the extract from the mixture of germs and cotyledons were similar in both soybeans. Regarding total polyphenol contents, the seed coat of black soybean had a higher polyphenol content than that of yellow soybean (29.0 +/- 0.56 and 0.45 +/- 0.02 mg/g, respectively). Interestingly, the mixture of the germ and cotyledon hydrolyzed by beta-glucosidase in both soybeans showed a stronger inhibitory effect on LDL oxidation than that before being hydrolyzed by beta-glucosidase. These results suggest that black soybeans may be more effective in inhibiting LDL oxidation than yellow soybeans because of total polyphenols contents in its seed coat. In addition, aglycones, which are rich in soybeans fermented or hydrolyzed by beta-glucosidase, may play a crucial role in the prevention of oxidation-related diseases. PMID:15913328

  8. Folding of Pollen Grains

    NASA Astrophysics Data System (ADS)

    Katifori, Eleni; Alben, Silas; Cerda, Enrique; Nelson, David; Dumais, Jacques

    2008-03-01

    At dehiscence, which occurs when the anther reaches maturity and opens, pollen grains dehydrate and their volume is reduced. The pollen wall deforms to accommodate the volume loss, and the deformation pathway depends on the initial turgid pollen grain geometry and the mechanical properties of the pollen wall. We demonstrate, using both experimental and theoretical approaches, that the design of the apertures (areas on the pollen wall where the stretching and the bending modulus are reduced) is critical for controlling the folding pattern, and ensures the pollen grain viability. An excellent fit to the experiments is obtained using a discretized version of the theory of thin elastic shells.

  9. Convection in grain refining

    NASA Technical Reports Server (NTRS)

    Flemings, M. C.; Szekely, J.

    1982-01-01

    The relationship between fluid flow phenomena, nucleation, and grain refinement in solidifying metals both in the presence and in the absence of a gravitational field was investigated. The reduction of grain size in hard-to-process melts; the effects of undercooling on structure in solidification processes, including rapid solidification processing; and control of this undercooling to improve structures of solidified melts are considered. Grain refining and supercooling thermal modeling of the solidification process, and heat and fluid flow phenomena in the levitated metal droplets are described.

  10. Differentiation of Effects due to Grain and Grain Boundary Traps in Laser Annealed Poly-Si Thin Film Transistors

    NASA Astrophysics Data System (ADS)

    Armstrong, G.; Uppal, S.; Brotherton, S.; Ayres, J.

    1998-04-01

    A new physical model based on two dimensional simulations for high quality laser re-crystallised poly-Si thin film transistors is presented. It has been shown that to adequately explain the improved subthreshold slope and the lack of saturation of the output characteristics in these transistors, it is essential to distribute the density of defect states between traps in the grains alongside traps localised at grain boundaries. A double exponential density of states has been extracted for thin film transistors (TFTs) annealed at different excimer laser energies, using the field effect conductance method. By splitting the density of states between grain traps and grain boundary traps good fits to the output characteristics have been achieved. Lack of saturation is shown to be due to decrease in potential barrier at grain boundaries with increase in drain bias. At high gate voltages, however, evidence of a self-heating effect similar to that observed in silicon-on-insulator (SOI) transistors is apparent.

  11. Para-aminobenzamidine linked regenerated cellulose membranes for plasminogen activator purification: Effect of spacer arm length and ligand density

    PubMed Central

    Fasoli, Ezio; Reyes, Yiaslin Ruiz; Guzman, Osiris Martinez; Rosado, Alexandra; Cruz, Vivian Rodriguez; Borges, Amaris; Martinez, Edmarie; Bansal, Vibha

    2013-01-01

    Despite membrane-based separations offering superior alternative to packed bed chromatographic processes, there has been a substantial lacuna in their actual application to separation processes. One of the major reasons behind this is the lack of availability of appropriately modified or end-group modifiable membranes. In this paper, an affinity membrane was developed using a commercially available serine protease inhibitor, para-aminobenzamidine (pABA). The membrane modification was optimized for protein binding capacity by varying: i) the length of the spacer arm (SA; 5-atoms, 7-atoms, and 14-atoms) linking the ligand to membrane surface; ii) the affinity ligand (pABA) density on membrane surface (5–25 nmoles per cm2). Resulting membranes were tested for their ability to bind plasminogen activators (PAs) from mono- and multi- component systems in batch mode. The membrane containing pABA linked through 7-atoms SA but similar ligand density as in the case of 5- or 14- atoms long SA was found to bind up to 1.6-times higher amounts of PA per nmole of immobilized ligand from conditioned HeLa cell culture media. However, membranes with similar ligand densities but different lengths of SA, showed comparable binding capacities in monocomponent system. In addition, the length of SA did not affect the selectivity of the ligand for PA. A clear inverse linear correlation was observed between ligand density and binding capacity until the point of PA binding optima was reached (11±1.0 nmoles per cm2) in mono- and multi- component systems for 7- as well as 14- atoms SA. Up to 200-fold purification was achieved in a single step separation of PA from HeLa conditioned media using these affinity membranes. The issues of ligand leaching and reuse of the membranes were also investigated. An extensive regeneration procedure allowed the preservation of approximately 95% of the PA binding capacity of the membranes even after five cycles of use. PMID:23703544

  12. The effect of grain size on aluminum anodes for Al-air batteries in alkaline electrolytes

    NASA Astrophysics Data System (ADS)

    Fan, Liang; Lu, Huimin

    2015-06-01

    Aluminum is an ideal material for metallic fuel cells. In this research, different grain sizes of aluminum anodes are prepared by equal channel angular pressing (ECAP) at room temperature. Microstructure of the anodes is examined by electron backscatter diffraction (EBSD) in scanning electron microscope (SEM). Hydrogen corrosion rates of the Al anodes in 4 mol L-1 NaOH are determined by hydrogen collection method. The electrochemical properties of the aluminum anodes are investigated in the same electrolyte using electrochemical impedance spectroscopy (EIS) and polarization curves. Battery performance is also tested by constant current discharge at different current densities. Results confirm that the electrochemical properties of the aluminum anodes are related to grain size. Finer grain size anode restrains hydrogen evolution, improves electrochemical activity and increases anodic utilization rate. The proposed method is shown to effectively improve the performance of Al-air batteries.

  13. Field measurements for food grain packing factors in US

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain is commonly stored in tall bins, often exceeding 30 m deep, in commercial storage facilities. Grain can support the large overbearing pressure without crushing; however, it yields somewhat to compaction due to the overbearing pressure leading to an increase in bulk density and change in volume...

  14. Cosmic ray density gradient and its dependence on the north-south asymmetry in solar activity

    NASA Technical Reports Server (NTRS)

    BADRUDDIN; Yadav, R. S.; Yadav, N. R.

    1985-01-01

    An analysis of the diurnal anisotropy on geomagnetically quiet days was performed using neutron monitor data at Deep River, Leeds, Rome and Tokyo, well distributed in latitude and longitude for the period 1964-79. The days were separated according to the polarity of IMF on that day. A significant difference in the amplitude and phase was found on towards and away polarity days, particularly during the years of high solar activity and large north-south asymmetry. These results (particularly time of maximum) on geomagnetically quiet days show some better relationship to the expected results as compared to the results obtained using all the days in a year.

  15. Kansas Agents Study Grain Marketing

    ERIC Educational Resources Information Center

    Schoeff, Robert W.

    1973-01-01

    Author is an extension specialist in feed and grain marketing for Kansas State University. He describes a tour set up to educate members of the Kansas Grain and Feed Dealers' Association in the area of grain marketing and exporting. (GB)

  16. Low Serum High Density Lipoprotein Cholesterol Concentration is an Independent Predictor for Enhanced Inflammation and Endothelial Activation

    PubMed Central

    Wan Ahmad, Wan Nor Hanis; Sakri, Farah; Mokhsin, Atiqah; Rahman, Thuhairah; Mohd Nasir, Nadzimah; Abdul-Razak, Suraya; Md Yasin, Mazapuspavina; Mohd Ismail, Aletza; Ismail, Zaliha; Nawawi, Hapizah

    2015-01-01

    Background Inflammation, endothelial activation and oxidative stress have been established as key events in the initiation and progression of atherosclerosis. High-density lipoprotein cholesterol (HDL-c) is protective against atherosclerosis and coronary heart disease, but its association with inflammation, endothelial activation and oxidative stress is not well established. Objectives (1) To compare the concentrations of biomarkers of inflammation, endothelial activation and oxidative stress in subjects with low HDL-c compared to normal HDL-c; (2) To examine the association and correlation between HDL-c and these biomarkers and (3) To determine whether HDL-c is an independent predictor of these biomarkers. Methods 422 subjects (mean age±SD = 43.2±11.9years) of whom 207 had low HDL-c concentrations (HDL-c <1.0mmol/L and <1.3mmol/L for males and females respectively) and 215 normal controls (HDL-c ≥1.0 and ≥1.3mmol/L for males and females respectively) were recruited in this study. The groups were matched for age, gender, ethnicity, smoking status, diabetes mellitus and hypertension. Fasting blood samples were collected for analysis of biomarkers of inflammation [high-sensitivity C-reactive protein (hsCRP) and Interleukin-6 (IL-6)], endothelial activation [soluble Vascular Cell Adhesion Molecule-1 (sVCAM-1), soluble Intercellular Adhesion Molecule-1 (sICAM-1) and E-selectin)] and oxidative stress [F2-Isoprostanes, oxidized Low Density Lipoprotein (ox-LDL) and Malondialdehyde (MDA)]. Results Subjects with low HDL-c had greater concentrations of inflammation, endothelial activation and oxidative stress biomarkers compared to controls. There were negative correlations between HDL-c concentration and biomarkers of inflammation (IL-6, p = 0.02), endothelial activation (sVCAM-1 and E-selectin, p = 0.029 and 0.002, respectively), and oxidative stress (MDA and F2-isoprostane, p = 0.036 and <0.0001, respectively). Multiple linear regression analysis showed HDL-c as an

  17. Catalytic stimulation by restrained active-site floppiness--the case of high density lipoprotein-bound serum paraoxonase-1.

    PubMed

    Ben-David, Moshe; Sussman, Joel L; Maxwell, Christopher I; Szeler, Klaudia; Kamerlin, Shina C L; Tawfik, Dan S

    2015-03-27

    Despite the abundance of membrane-associated enzymes, the mechanism by which membrane binding stabilizes these enzymes and stimulates their catalysis remains largely unknown. Serum paraoxonase-1 (PON1) is a lipophilic lactonase whose stability and enzymatic activity are dramatically stimulated when associated with high-density lipoprotein (HDL) particles. Our mutational and structural analyses, combined with empirical valence bond simulations, reveal a network of hydrogen bonds that connect HDL binding residues with Asn168--a key catalytic residue residing >15Å from the HDL contacting interface. This network ensures precise alignment of N168, which, in turn, ligates PON1's catalytic calcium and aligns the lactone substrate for catalysis. HDL binding restrains the overall motion of the active site and particularly of N168, thus reducing the catalytic activation energy barrier. We demonstrate herein that disturbance of this network, even at its most far-reaching periphery, undermines PON1's activity. Membrane binding thus immobilizes long-range interactions via second- and third-shell residues that reduce the active site's floppiness and pre-organize the catalytic residues. Although this network is critical for efficient catalysis, as demonstrated here, unraveling these long-rage interaction networks is challenging, let alone their implementation in artificial enzyme design.

  18. Catalytic activity of bimetallic nickel alloys for solid-oxide fuel cell anode reactions from density-functional theory

    NASA Astrophysics Data System (ADS)

    An, Wei; Gatewood, Daniel; Dunlap, Brett; Turner, C. Heath

    2011-05-01

    We present density-functional theory calculations of the chemisorption of atomic species O, S, C, H and reaction intermediates OH, SH, and CHn (n = 1, 2, and 3) on M/Ni alloy model catalysts (M = Bi, Mo, Fe, Co, and Cu). The activity of the Ni alloy catalysts for solid-oxide fuel cell (SOFC) anode oxidation reactions is predicted, based on a simple descriptor, i.e., the binding energy of oxygen. First, we find that the binding of undesirable intermediates, such as C and S, can be inhibited and the catalytic activity of planar Ni-based anodes can be tuned towards oxidation by selectively forming a bimetallic surface alloy. In particular, Cu/Ni, Fe/Ni, and Co/Ni anode catalysts are found to be most active towards anode oxidation. On the other hand, the Mo/Ni alloy surface is predicted to be the most effective catalyst in terms of inhibiting the deposition of C and S (while still preserving relatively high catalytic activity). The formation of a surface alloy, which has the alloy element enriched on the topmost surface, was found to be critical to the activity of the Ni alloy catalysts.

  19. Microstructure and nanoindentation of the CLAM steel with nanocrystalline grains under Xe irradiation

    NASA Astrophysics Data System (ADS)

    Chang, Yongqin; Zhang, Jing; Li, Xiaolin; Guo, Qiang; Wan, Farong; Long, Yi

    2014-12-01

    This work presents an early look at irradiation effects on China low activation martensitic (CLAM) steel with nanocrystalline grains (NC-CLAM steels) under 500 keV Xe-ion bombardment at room temperature to doses up to 5.3 displacements per atom (dpa). The microstructure in the topmost region of the steel is composed of nanocrystalline grains with an average diameter of 13 nm. As the samples were implanted at low dose, the nanocrystalline grains had martensite lath structure, and many dislocations and high density bubbles were introduced into the NC-CLAM steels. As the irradiation dose up to 5.3 dpa, a tangled dislocation network exists in the lath region, and the size of the bubbles increases. X-ray diffraction results show that the crystal quality decreases after irradiation, although the nanocrystals obviously coarsen. Grain growth under irradiation may be ascribed to the direct impact of the thermal spike on grain boundaries in the NC-CLAM steels. In irradiated samples, a compressive stress exists in the surface layer because of grain growth and irradiation-introduced defects, while the irradiation introduced grain-size coarsening and defects gradients from the surface to matrix result in a tensile stress in the irradiated NC-CLAM steels. Nanoindentation was used to estimate changes in mechanical properties during irradiation, and the results show that the hardness of the NC-CLAM steels increases with increasing irradiation dose, which was ascribed to the competition between the grain boundaries and the irradiation-introduced defects.

  20. Metal-Organic Frameworks as Highly Active Electrocatalysts for High-Energy Density, Aqueous Zinc-Polyiodide Redox Flow Batteries.

    PubMed

    Li, Bin; Liu, Jian; Nie, Zimin; Wang, Wei; Reed, David; Liu, Jun; McGrail, Pete; Sprenkle, Vincent

    2016-07-13

    The new aqueous zinc-polyiodide redox flow battery (RFB) system with highly soluble active materials as well as ambipolar and bifunctional designs demonstrated significantly enhanced energy density, which shows great potential to reduce RFB cost. However, the poor kinetic reversibility and electrochemical activity of the redox reaction of I3(-)/I(-) couples on graphite felts (GFs) electrode can result in low energy efficiency. Two nanoporous metal-organic frameworks (MOFs), MIL-125-NH2 and UiO-66-CH3, that have high surface areas when introduced to GF surfaces accelerated the I3(-)/I(-) redox reaction. The flow cell with MOF-modified GFs serving as a positive electrode showed higher energy efficiency than the pristine GFs; increases of about 6.4% and 2.7% occurred at the current density of 30 mA/cm(2) for MIL-125-NH2 and UiO-66-CH3, respectively. Moreover, UiO-66-CH3 is more promising due to its excellent chemical stability in the weakly acidic electrolyte. This letter highlights a way for MOFs to be used in the field of RFBs. PMID:27267589

  1. Source segregation and food waste prevention activities in high-density households in a deprived urban area.

    PubMed

    Rispo, A; Williams, I D; Shaw, P J

    2015-10-01

    A waste audit and a household questionnaire survey were conducted in high-density housing estates in one of the most economically and socially deprived areas of England (Haringey, London). Such areas are under-represented in published research. The study examined source segregation, potential participation in a food waste segregation scheme, and food waste prevention activities in five estates (1034 households). The results showed that: contamination of recyclables containers was low; ca. 28% of the mixed residual waste's weight was recyclable; food waste comprised a small proportion of the waste from these residents, probably because of their relatively disadvantaged economic circumstances; and the recycling profile reflected an intermittent pattern of behaviour. Although the majority of respondents reported that they would participate in a food waste separation scheme, the response rate was low and many responses of "don't know" were recorded. Municipalities committed to foster improved diversion from landfill need to recognise that there is no "quick and easy fix", regardless of local or national aspirations. Lasting and sustained behaviour change requires time and the quality of service provision and associated infrastructure play a fundamental role in facilitating residents to participate effectively in waste management activities that maximise capture of source-segregated materials. Populations in deprived areas that reside in high-rise, high-density dwellings are "hard-to-reach" in terms of participation in recycling schemes and exceptional efforts and additional resources are usually required to improve performance. PMID:26233881

  2. Active measurements of the thermal electron density and temperature from the Mercury Magnetospheric Orbiter of the BepiColombo mission

    NASA Astrophysics Data System (ADS)

    Trotignon, J. G.; Beghin, C.; Matsumoto, H.; Kojima, H.; Hashimoto, K.; Blomberg, L.; Lebreton, J. P.; Masson, A.; Hamelin, M.; Pottelette, R.

    The thermal component of the Mercury's electron population remains to be investigated. It is one of the scientific objectives of the Plasma Wave Investigation, PWI, consortium to determine its influence on the formation and dynamics of the planetary magnetosphere as a function of the solar activity. The Active Measurement of Mercury's Plasma, AM2P, experiment has therefore been proposed as part of the PWI to measure the density and temperature of the thermal electron population all along the Mercury Magnetospheric Orbiter of the BepiColombo mission. These two aeronomical parameters shall be deduced from the measurements of the self- and mutual-impedances of the MEFISTO (Mercury Electric Field In Situ TOol) double-sphere antenna in a frequency range comprising the expected plasma frequency. The purpose of the current presentation is: 1) to set the AM2P scientific objectives, 2) to give the principle of measurements, 3) to describe the electronics device, and 4) to show the ability of the AM2P to make reliable and accurate measurements of the thermal plasma density and temperature in the Hermean magnetosphere, as well as in the solar wind at 0.31-0.47 AU from the Sun. The latter point has been established from analytical and numerical simulations.

  3. Active measurement of the thermal electron density and temperature on the Mercury Magnetospheric Orbiter of the BepiColombo mission

    NASA Astrophysics Data System (ADS)

    Trotignon, J. G.; Béghin, C.; Lagoutte, D.; Michau, J. L.; Matsumoto, H.; Kojima, H.; Hashimoto, K.; Kasaba, Y.; Blomberg, L. G.; Lebreton, J. P.; Masson, A.; Hamelin, M.; Pottelette, R.

    2006-01-01

    The thermal component of Mercury's electron population has never been measured. One scientific objective of the Plasma Wave Investigation consortium, PWI, is to determine the influence of the thermal plasma upon the formation and dynamics of the planetary magnetosphere, as a function of solar activity. The Active Measurement of Mercury's Plasma experiment, AM 2P, has been proposed as part of PWI, to monitor the density and temperature of the thermal electron population, during the whole mission of the Mercury Magnetospheric Orbiter of BepiColombo. These two physical parameters will be deduced from the measurements of the self- and mutual-impedances of the MEFISTO (Mercury Electric Field In Situ TOol) double-sphere antenna, in a frequency range comprising the expected plasma frequency. The in situ measurement of the antenna impedance is also essential for calibrating the electric antenna which measures the natural waves; it will allow, in particular, the effective length of the antenna to be calculated as a function of frequency and plasma conditions. The purpose of this paper is to define the scientific objectives of AM 2P, to explain the principle of the measurement, to describe the electronic device, and to show the ability of AM 2P to make reliable and accurate measurements of the thermal plasma density and temperature in the Hermean magnetosphere, as well as in the solar wind at heliocentric distances of 0.31-0.47 AU. The potential performance of this instrument has been evaluated using both an analytical approach and numerical simulations.

  4. Source segregation and food waste prevention activities in high-density households in a deprived urban area.

    PubMed

    Rispo, A; Williams, I D; Shaw, P J

    2015-10-01

    A waste audit and a household questionnaire survey were conducted in high-density housing estates in one of the most economically and socially deprived areas of England (Haringey, London). Such areas are under-represented in published research. The study examined source segregation, potential participation in a food waste segregation scheme, and food waste prevention activities in five estates (1034 households). The results showed that: contamination of recyclables containers was low; ca. 28% of the mixed residual waste's weight was recyclable; food waste comprised a small proportion of the waste from these residents, probably because of their relatively disadvantaged economic circumstances; and the recycling profile reflected an intermittent pattern of behaviour. Although the majority of respondents reported that they would participate in a food waste separation scheme, the response rate was low and many responses of "don't know" were recorded. Municipalities committed to foster improved diversion from landfill need to recognise that there is no "quick and easy fix", regardless of local or national aspirations. Lasting and sustained behaviour change requires time and the quality of service provision and associated infrastructure play a fundamental role in facilitating residents to participate effectively in waste management activities that maximise capture of source-segregated materials. Populations in deprived areas that reside in high-rise, high-density dwellings are "hard-to-reach" in terms of participation in recycling schemes and exceptional efforts and additional resources are usually required to improve performance.

  5. Metal-Organic Frameworks as Highly Active Electrocatalysts for High-Energy Density, Aqueous Zinc-Polyiodide Redox Flow Batteries.

    PubMed

    Li, Bin; Liu, Jian; Nie, Zimin; Wang, Wei; Reed, David; Liu, Jun; McGrail, Pete; Sprenkle, Vincent

    2016-07-13

    The new aqueous zinc-polyiodide redox flow battery (RFB) system with highly soluble active materials as well as ambipolar and bifunctional designs demonstrated significantly enhanced energy density, which shows great potential to reduce RFB cost. However, the poor kinetic reversibility and electrochemical activity of the redox reaction of I3(-)/I(-) couples on graphite felts (GFs) electrode can result in low energy efficiency. Two nanoporous metal-organic frameworks (MOFs), MIL-125-NH2 and UiO-66-CH3, that have high surface areas when introduced to GF surfaces accelerated the I3(-)/I(-) redox reaction. The flow cell with MOF-modified GFs serving as a positive electrode showed higher energy efficiency than the pristine GFs; increases of about 6.4% and 2.7% occurred at the current density of 30 mA/cm(2) for MIL-125-NH2 and UiO-66-CH3, respectively. Moreover, UiO-66-CH3 is more promising due to its excellent chemical stability in the weakly acidic electrolyte. This letter highlights a way for MOFs to be used in the field of RFBs.

  6. Add-on rosiglitazone therapy improves plasminogen activity and high-density lipoprotein cholesterol in type 2 diabetes mellitus.

    PubMed

    Mustaffa, Nazri; Ibrahim, Suhairi; Abdullah, Wan Zaidah; Yusof, Zurkurnai

    2011-09-01

    Rosiglitazone is an oral hypoglycaemic agent of the thiazolidinedione group. This study aimed to assess changes in the diabetic prothrombotic state via plasminogen activity and changes in surrogate markers of atherosclerotic burden via ankle-brachial pressure index (ABPI) measurements after rosiglitazone was added to a pre-existing type 2 diabetes mellitus treatment regime. A nonblinded interventional study was designed. Fifty-nine patients were enrolled. Rosiglitazone-naïve patients were prescribed oral rosiglitazone 4 mg daily for 10 weeks. ABPI, plasminogen activity, glycosylated haemoglobin (HbA1c) and fasting lipid profile were measured pretreatment and post-treatment. Forty-eight patients completed the study. At the end of this study, mean plasminogen activity improvement was nearly 16% (P<0.05), mean ABPI improvement was 0.01 (P=0.439), mean HbA1c reduction was 0.51% (P<0.05), mean total cholesterol (TC) increase was 0.36 mmol/l (P<0.05), mean high-density lipoprotein cholesterol (HDL-C) increase was 0.15 mmol/l (P<0.05) and mean low-density lipoprotein cholesterol increased by 0.19 mmol/l (P=0.098). Rosiglitazone significantly improved plasminogen activity. There was also significant HbA1c reduction, and rise in both TC and HDL-C. Thus, rosiglitazone potentially improves the atherosclerotic burden and prothrombotic state. In future, more studies are needed to confirm the relationship between rosiglitazone, fibrinolytic system and atheromatous reduction in type 2 diabetes mellitus. PMID:21537159

  7. Advantageous grain boundaries in iron pnictide superconductors

    PubMed Central

    Katase, Takayoshi; Ishimaru, Yoshihiro; Tsukamoto, Akira; Hiramatsu, Hidenori; Kamiya, Toshio; Tanabe, Keiichi; Hosono, Hideo

    2011-01-01

    High critical temperature superconductors have zero power consumption and could be used to produce ideal electric power lines. The principal obstacle in fabricating superconducting wires and tapes is grain boundaries—the misalignment of crystalline orientations at grain boundaries, which is unavoidable for polycrystals, largely deteriorates critical current density. Here we report that high critical temperature iron pnictide superconductors have advantages over cuprates with respect to these grain boundary issues. The transport properties through well-defined bicrystal grain boundary junctions with various misorientation angles (θGB) were systematically investigated for cobalt-doped BaFe2As2 (BaFe2As2:Co) epitaxial films fabricated on bicrystal substrates. The critical current density through bicrystal grain boundary (JcBGB) remained high (>1 MA cm−2) and nearly constant up to a critical angle θc of ∼9°, which is substantially larger than the θc of ∼5° for YBa2Cu3O7–δ. Even at θGB>θc, the decay of JcBGB was much slower than that of YBa2Cu3O7–δ. PMID:21811238

  8. Relict grains in chondrules

    NASA Technical Reports Server (NTRS)

    Rambaldi, E. R.

    1981-01-01

    Attention is given to the fact that a significant fraction of the chondrules from ordinary chondrites contain silicate grains that survived the chondrule formation process without melting. Typically, these grains consist of coarse olivine, rarely orthopyroxene, crystals located in the core of chondrules and displaying a zoning that is inconsistent with crystallization from a silicate melt. It is noted that the relict grains still preserve the imprint of processes that occurred in the solar nebula and, in some cases, may include the isotopic record of interstellar grains. Information is presented on the chondrule precursor materials and the process of chondrule formation which was acquired by a compositional and textural study of three of the most unequilibrated type 3 ordinary chondrites.

  9. Grain-scale processes in actively deforming magma mushes: New insights from electron backscatter diffraction (EBSD) analysis of biotite schlieren in the Jizera granite, Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Žák, Jiří; Verner, Kryštof; Týcová, Patricie

    2008-12-01

    In the porphyritic Jizera granite, Bohemian Massif, three distinct types of lattice-preferred orientations of biotite grains were revealed in schlieren-delineated magmatic structures using the electron backscatter diffraction (EBSD) method. (1) Biotite basal planes (001) reorient from schlieren-subparallel near the schlieren base to schlieren-perpendicular in the upper part of the schlieren. Both orientations share subhorizontal ˜N-S to ˜NNE-SSW-trending a axes. (2) In some domains, the a axes are steep and at a high angle to the schlieren plane while the c axes plunge shallowly and rotate around an ill-defined a axis. (3) In other domains, the EBSD coincides with background magnetic fabric of the host granite revealed using the anisotropy of magnetic susceptibility (AMS) method: that is, the a axes plunge shallowly to the SE or NW while the c axes are subhorizontal and cluster around the ˜NE-SW trend. These multiple biotite orientations in the schlieren are interpreted to reflect (1) velocity-gradient in laminar magma flow along channel-like conduits, localized within the high-strength host phenocryst framework, (2) grain-scale gravity-driven constrictional deformation of the magma mush, and (3) overprinting background (tectonic?) deformation transmitted across large parts of the magma chamber prior to its final crystallization. The grain-scale mechanisms of biotite fabric acquisition in the schlieren presumably involved rotation of biotite crystals during flow, with the biotite alignment reflecting the flow geometry and kinematics, replaced after flow cessation by melt-aided grain-boundary sliding of those biotite crystals still enclosed in melt pockets within otherwise static, highly crystallized magma mush. The latter process was sufficient to reorient biotite grains but not to cause destruction of the schlieren. Using the Jizera granite as a case example, we argue that the lattice-preferred orientation of mineral grains in mafic schlieren is highly

  10. Grains in galactic haloes.

    NASA Astrophysics Data System (ADS)

    Ferrara, A.; Barsella, B.; Ferrini, F.; Greenberg, J. M.; Aiello, S.

    1989-12-01

    The authors considered the effect of extensive forces on dust grains subjected to the light and matter distribution of the spiral galaxy NGC 3198. They have shown that the combined force on a small particle located above the plane of a galactic disk may be either attractive or repulsive depending on a variety of parameters. The authors present here the preliminary results of the study of the motion of a dust grain for NGC 3198.

  11. High Levels of Serum DPP-4 Activity Are Associated with Low Bone Mineral Density in Obese Postmenopausal Women

    PubMed Central

    2016-01-01

    Background Dipeptidyl peptidase 4/CD26 (DPP-4) is a widely expressed cell surface serine protease. DPP-4 inhibitors, one of common anti-diabetic agents play a protective role in bone metabolism in recent studies. A soluble form of DPP-4 is found in serum, and exhibits DPP-4 enzymatic activity. However, the physiological role of serum or soluble DPP-4 and its relationship with DPP-4 enzymatic function remain poorly understood. The aims of current study were to determine the association between serum DPP-4 activity and bone mineral density (BMD) in postmenopausal women. Methods We recruited data and serum samples from 124 consecutive healthy postmenopausal women aged >50 years. We divided study subjects into obese (body mass index [BMI] ≥25 kg/m2) and non-obese (BMI <25 kg/m2) postmenopausal women and examined the correlation between serum DPP-4 activity and clinical variables in each groups. Results A total of 124 postmenopausal women was enrolled, with a mean age of 59.9±7.1 years. The mean BMI of the study patients was 24.4±2.8 kg/m2. Regarding bone turnover markers, serum DPP-4 activity was positively correlated with serum calcium concentrations, intact parathyroid hormone, and serum C-telopeptide levels in all of the study subjects. However, there was no association between serum DPP-4 activity and BMD in the spine or femoral neck in all of the study subjects. Serum DPP-4 activity was negatively correlated (R=−0.288, P=0.038) with BMD of the spine in obese postmenopausal women. Conclusion This study demonstrated for the first time that serum soluble DPP-4 activity was negatively correlated with BMD in obese postmenopausal women. PMID:26676330

  12. High capacitance of coarse-grained carbide derived carbon electrodes

    DOE PAGES

    Dyatkin, Boris; Gogotsi, Oleksiy; Malinovskiy, Bohdan; Zozulya, Yuliya; Simon, Patrice; Gogotsi, Yury

    2016-01-01

    Here, we report exceptional electrochemical properties of supercapacitor electrodes composed of large, granular carbide-derived carbon (CDC) particles. We synthesized 70–250 μm sized particles with high surface area and a narrow pore size distribution, using a titanium carbide (TiC) precursor. Electrochemical cycling of these coarse-grained powders defied conventional wisdom that a small particle size is strictly required for supercapacitor electrodes and allowed high charge storage densities, rapid transport, and good rate handling ability. Moreover, the material showcased capacitance above 100 F g-1 at sweep rates as high as 250 mV s-1 in organic electrolyte. 250–1000 micron thick dense CDC films withmore » up to 80 mg cm-2 loading showed superior areal capacitances. The material significantly outperformed its activated carbon counterpart in organic electrolytes and ionic liquids. Furthermore, large internal/external surface ratio of coarse-grained carbons allowed the resulting electrodes to maintain high electrochemical stability up to 3.1 V in ionic liquid electrolyte. In addition to presenting novel insights into the electrosorption process, these coarse-grained carbons offer a pathway to low-cost, high-performance implementation of supercapacitors in automotive and grid-storage applications.« less

  13. High capacitance of coarse-grained carbide derived carbon electrodes

    SciTech Connect

    Dyatkin, Boris; Gogotsi, Oleksiy; Malinovskiy, Bohdan; Zozulya, Yuliya; Simon, Patrice; Gogotsi, Yury

    2016-01-01

    Here, we report exceptional electrochemical properties of supercapacitor electrodes composed of large, granular carbide-derived carbon (CDC) particles. We synthesized 70–250 μm sized particles with high surface area and a narrow pore size distribution, using a titanium carbide (TiC) precursor. Electrochemical cycling of these coarse-grained powders defied conventional wisdom that a small particle size is strictly required for supercapacitor electrodes and allowed high charge storage densities, rapid transport, and good rate handling ability. Moreover, the material showcased capacitance above 100 F g-1 at sweep rates as high as 250 mV s-1 in organic electrolyte. 250–1000 micron thick dense CDC films with up to 80 mg cm-2 loading showed superior areal capacitances. The material significantly outperformed its activated carbon counterpart in organic electrolytes and ionic liquids. Furthermore, large internal/external surface ratio of coarse-grained carbons allowed the resulting electrodes to maintain high electrochemical stability up to 3.1 V in ionic liquid electrolyte. In addition to presenting novel insights into the electrosorption process, these coarse-grained carbons offer a pathway to low-cost, high-performance implementation of supercapacitors in automotive and grid-storage applications.

  14. High capacitance of coarse-grained carbide derived carbon electrodes

    NASA Astrophysics Data System (ADS)

    Dyatkin, Boris; Gogotsi, Oleksiy; Malinovskiy, Bohdan; Zozulya, Yuliya; Simon, Patrice; Gogotsi, Yury

    2016-02-01

    We report exceptional electrochemical properties of supercapacitor electrodes composed of large, granular carbide-derived carbon (CDC) particles. Using a titanium carbide (TiC) precursor, we synthesized 70-250 μm sized particles with high surface area and a narrow pore size distribution. Electrochemical cycling of these coarse-grained powders defied conventional wisdom that a small particle size is strictly required for supercapacitor electrodes and allowed high charge storage densities, rapid transport, and good rate handling ability. The material showcased capacitance above 100 F g-1 at sweep rates as high as 250 mV s-1 in organic electrolyte. 250-1000 micron thick dense CDC films with up to 80 mg cm-2 loading showed superior areal capacitances. The material significantly outperformed its activated carbon counterpart in organic electrolytes and ionic liquids. Furthermore, large internal/external surface ratio of coarse-grained carbons allowed the resulting electrodes to maintain high electrochemical stability up to 3.1 V in ionic liquid electrolyte. In addition to presenting novel insights into the electrosorption process, these coarse-grained carbons offer a pathway to low-cost, high-performance implementation of supercapacitors in automotive and grid-storage applications.

  15. Screening of catalytic oxygen reduction reaction activity of metal-doped graphene by density functional theory

    NASA Astrophysics Data System (ADS)

    Chen, Xin; Chen, Shuangjing; Wang, Jinyu

    2016-08-01

    Graphene doping is a promising direction for developing effective oxygen reduction reaction (ORR) catalysts. In this paper, we computationally investigated the ORR performance of 10 kinds of metal-doped graphene (M-G) catalysts, namely, Al-, Si-, Mn-, Fe-, Co-, Ni-, Pd-, Ag-, Pt-, and Au-G. The results shown that the binding energies of the metal atoms incorporated into the graphene vacancy are higher than their bulk cohesive energies, indicating the formed M-G catalysts are even more stable than the corresponding bulk metal surfaces, and thus avoid the metals dissolution in the reaction environment. We demonstrated that the linear relation among the binding energies of the ORR intermediates that found on metal-based materials does not hold for the M-G catalysts, therefore a single binding energy of intermediate alone is not sufficient to evaluate the ORR activity of an arbitrary catalyst. By analysis of the detailed ORR processes, we predicted that the Au-, Co-, and Ag-G materials can be used as the ORR catalysts.

  16. Rates of Space Weathering in Lunar Regolith Grains

    NASA Technical Reports Server (NTRS)

    Zhang, S.; Keller, L. P.

    2012-01-01

    While the processes and products of lunar space weathering are reasonably well-studied, their accumulation rates in lunar soils are poorly constrained. Previously, we showed that the thickness of solar wind irradiated rims on soil grains is a smooth function of their solar flare particle track density, whereas the thickness of vapor-deposited rims was largely independent of track density [1]. Here, we have extended these preliminary results with data on additional grains from other mature soils.

  17. Rate of H2 formation on amorphous grains

    NASA Technical Reports Server (NTRS)

    Smoluchowski, R.

    1981-01-01

    The rate of formation of molecular hydrogen from hydrogen atoms adsorbed on amorphous grains taken to represent interstellar dust grains is analyzed. Following a brief review of the structure and thermodynamics of amorphous grains and the evidence that interstellar grains are indeed amorphous, consideration is given to the mechanism of formation of H2 molecules by the impact of H atoms on grains with adsorbed H atoms, and it is concluded that on amorphous grains, molecule formation will only occur if H atoms are adsorbed within a distance on the order of 10 A of each other. Rates of H2 formation on single crystal and polycrystalline grains are then calculated and compared with those for amorphous grains, and it is shown that, except for certain temperatures and high H atom densities, the rates of H2 formation on polycrystalline and amorphous grains are up to a few orders of magnitude lower than on single crystals. The results suggest that amorphous grains will lead to H2 clouds with irregular and sharply delineated features in contrast to the more uniform clouds formed on crystalline grains.

  18. A Rare Allele of GS2 Enhances Grain Size and Grain Yield in Rice.

    PubMed

    Hu, Jiang; Wang, Yuexing; Fang, Yunxia; Zeng, Longjun; Xu, Jie; Yu, Haiping; Shi, Zhenyuan; Pan, Jiangjie; Zhang, Dong; Kang, Shujing; Zhu, Li; Dong, Guojun; Guo, Longbiao; Zeng, Dali; Zhang, Guangheng; Xie, Lihong; Xiong, Guosheng; Li, Jiayang; Qian, Qian

    2015-10-01

    Grain size determines grain weight and affects grain quality. Several major quantitative trait loci (QTLs) regulating grain size have been cloned; however, our understanding of the underlying mechanism that regulates the size of rice grains remains fragmentary. Here, we report the cloning and characterization of a dominant QTL, grain size on chromosome 2 (GS2), which encodes Growth-Regulating Factor 4 (OsGRF4), a transcriptional regulator. GS2 localizes to the nucleus and may act as a transcription activator. A rare mutation of GS2 affecting the binding site of a microRNA, OsmiR396c, causes elevated expression of GS2/OsGRF4. The increase in GS2 expression leads to larger cells and increased numbers of cells, which thus enhances grain weight and yield. The introduction of this rare allele of GS2/OsGRF4 into rice cultivars could significantly enhance grain weight and increase grain yield, with possible applications in breeding high-yield rice varieties.

  19. Recording extracellular neural activity in the behaving monkey using a semichronic and high-density electrode system.

    PubMed

    Mendoza, Germán; Peyrache, Adrien; Gámez, Jorge; Prado, Luis; Buzsáki, György; Merchant, Hugo

    2016-08-01

    We describe a technique to semichronically record the cortical extracellular neural activity in the behaving monkey employing commercial high-density electrodes. After the design and construction of low cost microdrives that allow varying the depth of the recording locations after the implantation surgery, we recorded the extracellular unit activity from pools of neurons at different depths in the presupplementary motor cortex (pre-SMA) of a rhesus monkey trained in a tapping task. The collected data were processed to classify cells as putative pyramidal cells or interneurons on the basis of their waveform features. We also demonstrate that short time cross-correlogram occasionally yields unit pairs with high short latency (<5 ms), narrow bin (<3 ms) peaks, indicative of monosynaptic spike transmission from pre- to postsynaptic neurons. These methods have been verified extensively in rodents. Finally, we observed that the pattern of population activity was repetitive over distinct trials of the tapping task. These results show that the semichronic technique is a viable option for the large-scale parallel recording of local circuit activity at different depths in the cortex of the macaque monkey and other large species. PMID:27169505

  20. Implications of Saito's coronal density model on the polar solar wind flow and heavy ion abundances. [mathematical models of proton flux density and solar activity

    NASA Technical Reports Server (NTRS)

    Feldman, W. C.

    1976-01-01

    A comparison of polar solar wind proton flux upper limits derived using a coronal density model, with Lyman alpha measurements of the length of the neutral H tail of comet Bennet at high latitudes, shows that either extended heating beyond 2 solar radii is necessary some of the time or that the model's polar densities are too low. Whichever possibility is the case, the fact that the solar wind particle flux does not appear to decrease with increasing latitude indicates that the heavy element content of the high latitude wind may be similar to that observed in the ecliptic. It was then shown that solar wind heavy ion observations at high latitudes allow a determination of the electron temperature at heights which bracket the nominal location of the coronal temperature maximum thus providing information concerning the magnitude and extent of mechanical dissipation in the intermediate corona.

  1. Temporal patterns of deer-vehicle collisions consistent with deer activity pattern and density increase but not general accident risk.

    PubMed

    Hothorn, Torsten; Müller, Jörg; Held, Leonhard; Möst, Lisa; Mysterud, Atle

    2015-08-01

    The increasing number of deer-vehicle collisions (DVCs) across Europe during recent decades poses a serious threat to human health and animal welfare and increasing costs for society. DVCs are triggered by both a human-related and a deer-related component. Mitigation requires an understanding of the processes driving temporal and spatial collision patterns. Separating human-related from deer-related processes is important for identifying potentially effective countermeasures, but this has rarely been done. We analysed two time series of 341,655 DVCs involving roe deer and 854,659 non-deer-related accidents (non-DVCs) documented between 2002 and 2011. Nonparametric smoothing and temporal parametric modelling were used to estimate annual, seasonal, weekly and diurnal patterns in DVCs, non-DVCs and adjusted DVCs. As we had access to data on both DVCs and non-DVCs, we were able to disentangle the relative role of human-related and deer-related processes contributing to the overall temporal DVC pattern. We found clear evidence that variation in DVCs was mostly driven by deer-related and not human-related activity on annual, seasonal, weekly and diurnal scales. A very clear crepuscular activity pattern with high activity after sunset and around sunrise throughout the year was identified. Early spring and the mating season between mid-July and mid-August are typically periods of high roe deer activity, and as expected we found a high number of DVC during these periods, although these patterns differed tremendously during different phases of a day. The role of human activity was mainly reflected in fewer DVCs on weekends than on weekdays. Over the ten-year study period, we estimated that DVCs increased by 25%, whereas the number of non-DVCs decreased by 10%. Increasing deer densities are the most likely driver behind this rise in DVCs. Precise estimates of DVC patterns and their relationship to deer and human activity patterns allow implementation of specific mitigation

  2. Fingering phenomena during grain-grain displacement

    NASA Astrophysics Data System (ADS)

    Mello, Nathália M. P.; Paiva, Humberto A.; Combe, G.; Atman, A. P. F.

    2016-05-01

    Spontaneous formation of fingered patterns during the displacement of dense granular assemblies was experimentally reported few years ago, in a radial Hele-Shaw cell. Here, by means of discrete element simulations, we have recovered the experimental findings and extended the original study to explore the control parameters space. In particular, using assemblies of grains with different geometries (monodisperse, bidisperse, or polydisperse), we measured the macroscopic stress tensor in the samples in order to confirm some conjectures proposed in analogy with Saffman-Taylor viscous fingering phenomena for immiscible fluids. Considering an axial setup which allows to control the discharge of grains and to follow the trajectory and the pressure gradient along the displacing interface, we have applied the Darcy law for laminar flow in fluids in order to measure an "effective viscosity" for each assembly combination, in an attempt to mimic variation of the viscosity ratio between the injected/displaced fluids in the Saffman-Taylor experiment. The results corroborate the analogy with the viscous fluids displacement, with the bidisperse assembly corresponding to the less viscous geometry. But, differently to fluid case, granular fingers only develop for a specific combination of displaced/injected geometries, and we have demonstrated that it is always related with the formation of a force chain network along the finger direction.

  3. Grain growth and experimental deformation of fine-grained ice aggregates

    NASA Astrophysics Data System (ADS)

    Diebold, Sabrina; de Bresser, Hans; Spiers, Chris; Durham, William B.; Stern, Laura

    2010-05-01

    measured by cryogenic SEM and image analysis techniques. We found clear evidence of grain growth and a significantly T-dependent variation of grain size distributions. The observations allow us to calibrate values for the grain size exponent n and the activation energy Q as used in conventional grain growth laws. We simulated grain growth of ice based on the microphysical model of Kellermann Slotemaker (2006). This model takes into account full grain size distributions and allows grain boundary migration driven by different acting forces. We will show the importance of these driving forces for grain growth and deformation in polycrystalline ice aggregates. References Kellermann Slotemaker, A., 2006. Dynamic recrystallization and grain growth in olivine rocks. PhD Thesis, Utrecht University, Utrecht, 187 pp. Stern, L., 1997. Grain-size-inducedweakening of H2O ices I and II and associated anisotropic recrystallization. Journal of Geophysical Research, 102 (B3): 5313-5325.

  4. Prenatal immune activation in mice blocks the effects of environmental enrichment on exploratory behavior and microglia density.

    PubMed

    Buschert, Jens; Sakalem, Marna E; Saffari, Roja; Hohoff, Christa; Rothermundt, Matthias; Arolt, Volker; Zhang, Weiqi; Ambrée, Oliver

    2016-06-01

    Adverse environmental factors including prenatal maternal infection are capable of inducing long-lasting behavioral and neural alterations which can enhance the risk to develop schizophrenia. It is so far not clear whether supportive postnatal environments are able to modify such prenatally-induced alterations. In rodent models, environmental enrichment influences behavior and cognition, for instance by affecting endocrinologic, immunologic, and neuroplastic parameters. The current study was designed to elucidate the influence of postnatal environmental enrichment on schizophrenia-like behavioral alterations induced by prenatal polyI:C immune stimulation at gestational day 9 in mice. Adult offspring were tested for amphetamine-induced locomotion, social interaction, and problem-solving behavior as well as expression of dopamine D1 and D2 receptors and associated molecules, microglia density and adult neurogenesis. Prenatal polyI:C treatment resulted in increased dopamine sensitivity and dopamine D2 receptor expression in adult offspring which was not reversed by environmental enrichment. Prenatal immune activation prevented the effects of environmental enrichment which increased exploratory behavior and microglia density in NaCl treated mice. Problem-solving behavior as well as the number of immature neurons was affected by neither prenatal immune stimulation nor postnatal environmental enrichment. The behavioral and neural alterations that persist into adulthood could not generally be modified by environmental enrichment. This might be due to early neurodevelopmental disturbances which could not be rescued or compensated for at a later developmental stage.

  5. Effects of season and host physiological state on the diversity, density, and activity of the arctic ground squirrel cecal microbiota.

    PubMed

    Stevenson, Timothy J; Duddleston, Khrystyne N; Buck, C Loren

    2014-09-01

    We examined the seasonal changes of the cecal microbiota of captive arctic ground squirrels (Urocitellus parryii) by measuring microbial diversity and composition, total bacterial density and viability, and short-chain fatty acid concentrations at four sample periods (summer, torpor, interbout arousal, and posthibernation). Abundance of Firmicutes was lower, whereas abundances of Bacteroidetes, Verrucomicrobia, and Proteobacteria were higher during torpor and interbout arousal than in summer. Bacterial densities and percentages of live bacteria were significantly higher in summer than during torpor and interbout arousal. Likewise, total short-chain fatty acid concentrations were significantly greater during summer than during torpor and interbout arousal. Concentrations of individual short-chain fatty acids varied across sample periods, with butyrate concentrations higher and acetate concentrations lower during summer than at all other sample periods. Characteristics of the gut community posthibernation were more similar to those during torpor and interbout arousal than to those during summer. However, higher abundances of the genera Bacteroides and Akkermansia occurred during posthibernation than during interbout arousal and torpor. Collectively, our results clearly demonstrate that seasonal changes in physiology associated with hibernation and activity affect the gut microbial community in the arctic ground squirrel. Importantly, similarities between the gut microbiota of arctic ground squirrels and thirteen-lined ground squirrels suggest the potential for a core microbiota during hibernation.

  6. GRAIN SORTING IN COMETARY DUST FROM THE OUTER SOLAR NEBULA

    SciTech Connect

    Wozniakiewicz, P. J.; Bradley, J. P.; Ishii, H. A.; Brownlee, D. E.; Kearsley, A. T.; Burchell, M. J.; Price, M. C.

    2012-12-01

    Most young stars are surrounded by a disk of gas and dust. Close to the hot stars, amorphous dust grains from the parent molecular cloud are reprocessed into crystals that are then distributed throughout the accretion disk. In some disks, there is a reduction in crystalline grain size with heliocentric distance from the star. We investigated crystalline grain size distributions in chondritic porous (CP) interplanetary dust particles (IDPs) believed to be from small, icy bodies that accreted in outer regions of the solar nebula. The grains are Mg-rich silicates and Fe-rich sulfides, the two most abundant minerals in CP IDPs. We find that they are predominantly <0.25 {mu}m in radius with a mean grain size that varies from one CP IDP to another. We report a size-density relationship between the silicates and sulfides. A similar size-density relationship between much larger silicate and sulfide grains in meteorites from the asteroid belt is ascribed to aerodynamic sorting. Since the silicate and sulfide grains in CP IDPs are theoretically too small for aerodynamic sorting, their size-density relationship may be due to another process capable of sorting small grains.

  7. Microwave sintering of nanophase ceramics without concomitant grain growth

    DOEpatents

    Eastman, Jeffrey A.; Sickafus, Kurt E.; Katz, Joel D.

    1993-01-01

    A method of sintering nanocrystalline material is disclosed wherein the nanocrystalline material is microwaved to heat the material to a temperature less than about 70% of the melting point of the nanocrystalline material expressed in degrees K. This method produces sintered nanocrystalline material having a density greater than about 95% of theoretical and an average grain size not more than about 3 times the average grain size of the nanocrystalline material before sintering. Rutile TiO.sub.2 as well as various other ceramics have been prepared. Grain growth of as little as 1.67 times has resulted with densities of about 90% of theoretical.

  8. Can we define an asymptotic value for the ice active surface site density for heterogeneous ice nucleation?

    NASA Astrophysics Data System (ADS)

    Niedermeier, Dennis; Augustin-Bauditz, Stefanie; Hartmann, Susan; Wex, Heike; Ignatius, Karoliina; Stratmann, Frank

    2015-05-01

    The immersion freezing behavior of droplets containing size-segregated, monodisperse feldspar particles was investigated. For all particle sizes investigated, a leveling off of the frozen droplet fraction was observed reaching a plateau within the heterogeneous freezing temperature regime (T >- 38°C). The frozen fraction in the plateau region was proportional to the particle surface area. Based on these findings, an asymptotic value for ice active surface site density ns, which we named ns⋆, could be determined for the investigated feldspar sample. The comparison of these results with those of other studies not only elucidates the general feasibility of determining such an asymptotic value but also shows that the value of ns⋆ strongly depends on the method of the particle surface area determination. However, such an asymptotic value might be an important input parameter for atmospheric modeling applications. At least it shows that care should be taken when ns is extrapolated to lower or higher temperature.

  9. Analytical gradients of the state-average complete active space self-consistent field method with density fitting

    SciTech Connect

    Delcey, Mickaël G.; Pedersen, Thomas Bondo; Aquilante, Francesco; Lindh, Roland

    2015-07-28

    An efficient implementation of the state-averaged complete active space self-consistent field (SA-CASSCF) gradients employing density fitting (DF) is presented. The DF allows a reduction both in scaling and prefactors of the different steps involved. The performance of the algorithm is demonstrated on a set of molecules ranging up to an iron-Heme b complex which with its 79 atoms and 811 basis functions is to our knowledge the largest SA-CASSCF gradient computed. For smaller systems where the conventional code could still be used as a reference, both the linear response calculation and the gradient formation showed a clear timing reduction and the overall cost of a geometry optimization is typically reduced by more than one order of magnitude while the accuracy loss is negligible.

  10. Analytical gradients of the state-average complete active space self-consistent field method with density fitting

    NASA Astrophysics Data System (ADS)

    Delcey, Mickaël G.; Pedersen, Thomas Bondo; Aquilante, Francesco; Lindh, Roland

    2015-07-01

    An efficient implementation of the state-averaged complete active space self-consistent field (SA-CASSCF) gradients employing density fitting (DF) is presented. The DF allows a reduction both in scaling and prefactors of the different steps involved. The performance of the algorithm is demonstrated on a set of molecules ranging up to an iron-Heme b complex which with its 79 atoms and 811 basis functions is to our knowledge the largest SA-CASSCF gradient computed. For smaller systems where the conventional code could still be used as a reference, both the linear response calculation and the gradient formation showed a clear timing reduction and the overall cost of a geometry optimization is typically reduced by more than one order of magnitude while the accuracy loss is negligible.

  11. CYLD, a deubiquitinase specific for lysine63-linked polyubiquitins, accumulates at the postsynaptic density in an activity-dependent manner

    SciTech Connect

    Dosemeci, Ayse; Thein, Soe; Yang, Yijung; Reese, Thomas S.; Tao-Cheng, Jung-Hwa

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer CYLD is a deubiquitinase specific for lysine63-linked polyubiquitins. Black-Right-Pointing-Pointer Presence of CYLD in PSDs is established by biochemistry and immunoEM. Black-Right-Pointing-Pointer CYLD accumulates on PSDs upon depolarization of neurons. Black-Right-Pointing-Pointer Accumulation of CYLD at PSDs may regulate trafficking/degradation of synaptic proteins. -- Abstract: Polyubiquitin chains on proteins flag them for distinct fates depending on the type of polyubiquitin linkage. While lysine48-linked polyubiquitination directs proteins to proteasomal degradation, lysine63-linked polyubiquitination promotes different protein trafficking and is involved in autophagy. Here we show that postsynaptic density (PSD) fractions from adult rat brain contain deubiquitinase activity that targets both lysine48 and lysine63-linked polyubiquitins. Comparison of PSD fractions with parent subcellular fractions by Western immunoblotting reveals that CYLD, a deubiquitinase specific for lysine63-linked polyubiquitins, is highly enriched in the PSD fraction. Electron microscopic examination of hippocampal neurons in culture under basal conditions shows immunogold label for CYLD at the PSD complex in approximately one in four synapses. Following depolarization by exposure to high K+, the proportion of CYLD-labeled PSDs as well as the labeling intensity of CYLD at the PSD increased by more than eighty percent, indicating that neuronal activity promotes accumulation of CYLD at the PSD. An increase in postsynaptic CYLD following activity would promote removal of lysine63-polyubiquitins from PSD proteins and thus could regulate their trafficking and prevent their autophagic degradation.

  12. Modeling high-pressure adsorption of gas mixtures on activated carbon and coal using a simplified local-density model.

    PubMed

    Fitzgerald, James E; Robinson, Robert L; Gasem, Khaled A M

    2006-11-01

    The simplified local-density (SLD) theory was investigated regarding its ability to provide accurate representations and predictions of high-pressure supercritical adsorption isotherms encountered in coalbed methane (CBM) recovery and CO2 sequestration. Attention was focused on the ability of the SLD theory to predict mixed-gas adsorption solely on the basis of information from pure gas isotherms using a modified Peng-Robinson (PR) equation of state (EOS). An extensive set of high-pressure adsorption measurements was used in this evaluation. These measurements included pure and binary mixture adsorption measurements for several gas compositions up to 14 MPa for Calgon F-400 activated carbon and three water-moistened coals. Also included were ternary measurements for the activated carbon and one coal. For the adsorption of methane, nitrogen, and CO2 on dry activated carbon, the SLD-PR can predict the component mixture adsorption within about 2.2 times the experimental uncertainty on average solely on the basis of pure-component adsorption isotherms. For the adsorption of methane, nitrogen, and CO2 on two of the three wet coals, the SLD-PR model can predict the component adsorption within the experimental uncertainties on average for all feed fractions (nominally molar compositions of 20/80, 40/60, 60/40, and 80/20) of the three binary gas mixture combinations, although predictions for some specific feed fractions are outside of their experimental uncertainties. PMID:17073487

  13. Para-aminobenzamidine linked regenerated cellulose membranes for plasminogen activator purification: effect of spacer arm length and ligand density.

    PubMed

    Fasoli, Ezio; Reyes, Yiaslin Ruiz; Guzman, Osiris Martinez; Rosado, Alexandra; Cruz, Vivian Rodriguez; Borges, Amaris; Martinez, Edmarie; Bansal, Vibha

    2013-07-01

    Despite membrane-based separations offering superior alternative to packed bed chromatographic processes, there has been a substantial lacuna in their actual application to separation processes. One of the major reasons behind this is the lack of availability of appropriately modified or end-group modifiable membranes. In this paper, an affinity membrane was developed using a commercially available serine protease inhibitor, para-aminobenzamidine (pABA). The membrane modification was optimized for protein binding capacity by varying: (i) the length of the spacer arm (SA; 5-atoms, 7-atoms, and 14-atoms) linking the ligand to membrane surface; (ii) the affinity ligand (pABA) density on membrane surface (5-25nmol/cm(2)). Resulting membranes were tested for their ability to bind plasminogen activators (PAs) from mono- and multi-component systems in batch mode. The membrane containing pABA linked through 7-atoms SA but similar ligand density as in the case of 5- or 14-atoms long SA was found to bind up to 1.6-times higher amounts of PA per nmoles of immobilized ligand from conditioned HeLa cell culture media. However, membranes with similar ligand densities but different lengths of SA, showed comparable binding capacities in mono-component system. In addition, the length of SA did not affect the selectivity of the ligand for PA. A clear inverse linear correlation was observed between ligand density and binding capacity until the point of PA binding optima was reached (11±1.0nmol/cm(2)) in mono- and multi-component systems for 7- as well as 14-atoms SA. Up to 200-fold purification was achieved in a single step separation of PA from HeLa conditioned media using these affinity membranes. The issues of ligand leaching and reuse of the membranes were also investigated. An extensive regeneration procedure allowed the preservation of approximately 95% of the PA binding capacity of the membranes even after five cycles of use. PMID:23703544

  14. Increased expression of low density granulocytes in juvenile-onset systemic lupus erythematosus patients correlates with disease activity.

    PubMed

    Midgley, A; Beresford, M W

    2016-04-01

    Neutrophils are implicated in a wide range of non-infectious inflammatory conditions. A subset of neutrophils in the peripheral circulation of systemic lupus erythematosus (SLE) patients has been described and termed low density granulocytes (LDGs). This study investigates the expression of LDG in juvenile-onset SLE (JSLE) patients compared to controls, and any correlations with disease activity.Neutrophils and LDGs were isolated from JSLE (n = 13) and paediatric non-inflammatory control patients (n = 12). Cell populations were assessed and compared using flow cytometry and morphological analysis. Standard clinical data, which included disease activity markers/scores, were collected for each patient.Significantly increased LDG expression (%mean ± SEM, range) was observed in JSLE patients (10.4 ± 3.26, 3.41-36.3) compared to controls (2.4 ± 0.44, 0.36-5.27; p = 0.005). A statistically significant positive correlation was observed between LDG expression and the British Isles Lupus Activity Group (correlation coefficient 0.685; p = 0.010) and SLE Disease Activity Index (correlation coefficient 0.567; p = 0.043) and the biomarker of dsDNA-antibodies (correlation coefficient 0.590; p = 0.043).Here we observe increased expression in LDGs in JSLE patients, which correlate with dsDNA antibody concentration and scores of disease activity. These correlations indicate that the increased LDG expression observed in this study may have a potential role in the pathogenesis of JSLE, and may be a useful biomarker.

  15. Oxidized High-Density Lipoprotein Impairs Endothelial Progenitor Cells' Function by Activation of CD36-MAPK-TSP-1 Pathways

    PubMed Central

    Wu, Jianxiang; He, Zhiqing; Gao, Xiang; Wu, Feng; Ding, Ru; Ren, Yusheng; Jiang, Qijun; Fan, Min

    2015-01-01

    Abstract Aims: High-density lipoprotein (HDL) levels inversely correlate with cardiovascular events due to the protective effects on vascular wall and stem cells, which are susceptible to oxidative modifications and then lead to potential pro-atherosclerotic effects. We proposed that oxidized HDL (ox-HDL) might lead to endothelial progenitor cells (EPCs) dysfunction and investigated underlying mechanisms. Results: ox-HDL was shown to increase apoptosis and intracellular reactive oxygen species levels, but to reduce migration, angiogenesis, and cholesterol efflux of EPCs in a dose-dependent manner. p38 mitogen-activated protein kinase (MAPK) and NF-κB were activated after ox-HDL stimulation, which also upregulated thrombospondin-1 (TSP-1) expression without affecting vascular endothelial growth factor. Effects caused by ox-HDL could be significantly attenuated by pretreatment with short hairpin RNA-mediated CD36 knockdown or probucol. Data of in vivo experiments and the inverse correlation of ox-HDL and circulating EPC numbers among patients with coronary artery diseases (CAD) or CAD and type 2 diabetes also supported it. Meanwhile, HDL separated from such patients could significantly increase cultured EPC's caspase 3 activity, further supporting our proposal. Innovation: This is the most complete study to date of how ox-HDL would impair EPCs function, which was involved with activation of CD36-p38 MAPK-TSP-1 pathways and proved by not only the inverse relationship between ox-HDL and circulating EPCs in clinic but also pro-apoptotic effects of HDL separated from patients' serum. Conclusion: Activation of CD36-p38 MAPK-TSP-1 pathways contributes to the pathological effects of ox-HDL on EPCs' dysfunction, which might be one of the potential etiological factors responsible for the disturbed neovascularization in chronic ischemic disease. Antioxid. Redox Signal. 22, 308–324. PMID:25313537

  16. A Pilot Study: Dietary Energy Density is Similar between Active Women with and without Exercise-Associated Menstrual Dysfunction

    PubMed Central

    Hand, Taryn M.; Howe, Stephanie; Cialdella-Kam, Lynn; Hoffman, Charlotte P. Guebels; Manore, Melinda

    2016-01-01

    Low energy availability (EA) (e.g., insufficient energy intake (EI) to match energy needs, including exercise energy expenditure) has been identified as a primary contributor to exercise-associated menstrual dysfunction (ExMD) in active women. For health reasons, active women may self-select diets lower in energy density (ED, kcal/g), which can inadvertently contribute to inadequate EI. Using data from two studies, we compared the ED of active women with ExMD (n = 9; 24 ± 6 years) to eumenorrheic (EU) active controls (EU: n = 18, 27 ± 6 years). ED was calculated from 6 to 7 days weighted food records using two methods: with/without beverages. ANOVA and Wilcoxon Rank-Sum were used to test group differences. ED was not different between groups, but there was a trend toward a lower median ED (10%) (p = 0.049 unadjusted; p = 0.098 adjusted) in the ExMD-group (Method 1—all beverages: ExMD = 1.01 kcal/g (range = 0.52–1.41), EU = 1.22 kcal/g (range = 0.72–1.72); Method 2—without beverages: ExMD = 1.51 kcal/g (range = 1.26–2.06), EU = 1.69 kcal/g (range = 1.42–2.54)). This lower ED represents a 9% decrease (~219 kcal/day) in EI (ExMD = 2237 ± 378 kcal/day; EU = 2456 ± 470 kcal/day; p > 0.05). EI and macro/micronutrient intakes were similar for groups. In the ExMD-group, low ED could contribute to lower EI and EA. Future research should examine the interaction of ED and exercise on appetite, EI, and EA in active women, especially those with ExMD. PMID:27104560

  17. A Pilot Study: Dietary Energy Density is Similar between Active Women with and without Exercise-Associated Menstrual Dysfunction.

    PubMed

    Hand, Taryn M; Howe, Stephanie; Cialdella-Kam, Lynn; Hoffman, Charlotte P Guebels; Manore, Melinda

    2016-01-01

    Low energy availability (EA) (e.g., insufficient energy intake (EI) to match energy needs, including exercise energy expenditure) has been identified as a primary contributor to exercise-associated menstrual dysfunction (ExMD) in active women. For health reasons, active women may self-select diets lower in energy density (ED, kcal/g), which can inadvertently contribute to inadequate EI. Using data from two studies, we compared the ED of active women with ExMD (n = 9; 24 ± 6 years) to eumenorrheic (EU) active controls (EU: n = 18, 27 ± 6 years). ED was calculated from 6 to 7 days weighted food records using two methods: with/without beverages. ANOVA and Wilcoxon Rank-Sum were used to test group differences. ED was not different between groups, but there was a trend toward a lower median ED (10%) (p = 0.049 unadjusted; p = 0.098 adjusted) in the ExMD-group (Method 1-all beverages: ExMD = 1.01 kcal/g (range = 0.52-1.41), EU = 1.22 kcal/g (range = 0.72-1.72); Method 2-without beverages: ExMD = 1.51 kcal/g (range = 1.26-2.06), EU = 1.69 kcal/g (range = 1.42-2.54)). This lower ED represents a 9% decrease (~219 kcal/day) in EI (ExMD = 2237 ± 378 kcal/day; EU = 2456 ± 470 kcal/day; p > 0.05). EI and macro/micronutrient intakes were similar for groups. In the ExMD-group, low ED could contribute to lower EI and EA. Future research should examine the interaction of ED and exercise on appetite, EI, and EA in active women, especially those with ExMD. PMID:27104560

  18. Synthesis, Density Functional Theory (DFT), Urease Inhibition and Antimicrobial Activities of 5-Aryl Thiophenes Bearing Sulphonylacetamide Moieties.

    PubMed

    Noreen, Mnaza; Rasool, Nasir; Gull, Yasmeen; Zubair, Muhammad; Mahmood, Tariq; Ayub, Khurshid; Nasim, Faiz-Ul-Hassan; Yaqoob, Asma; Zia-Ul-Haq, Muhammad; de Feo, Vincenzo

    2015-01-01

    A variety of novel 5-aryl thiophenes 4a-g containing sulphonylacetamide (sulfacetamide) groups were synthesized in appreciable yields via Pd[0] Suzuki cross coupling reactions. The structures of these newly synthesized compounds were determined using spectral data and elemental analysis. Density functional theory (DFT) studies were performed using the B3LYP/6-31G (d, p) basis set to gain insight into their structural properties. Frontier molecular orbital (FMOs) analysis of all compounds 4a-g was computed at the same level of theory to get an idea about their kinetic stability. The molecular electrostatic potential (MEP) mapping over the entire stabilized geometries of the molecules indicated the reactive sites. First hyperpolarizability analysis (nonlinear optical response) were simulated at the B3LYP/6-31G (d, p) level of theory as well. The compounds were further evaluated for their promising antibacterial and anti-urease activities. In this case, the antibacterial activities were estimated by the agar well diffusion method, whereas the anti-urease activities of these compounds were determined using the indophenol method by quantifying the evolved ammonia produced. The results revealed that all the sulfacetamide derivatives displayed antibacterial activity against Bacillus subtiles, Escherichia coli, Staphylococcus aureus, Shigella dysenteriae, Salmonella typhae, Pseudomonas aeruginosa at various concentrations. Furthermore, the compound 4g N-((5-(4-chlorophenyl)thiophen-2-yl)sulfonyl) acetamide showed excellent urease inhibition with percentage inhibition activity ~46.23 ± 0.11 at 15 µg/mL with IC50 17.1 µg/mL. Moreover, some other compounds 4a-f also exhibited very good inhibition against urease enzyme. PMID:26556326

  19. Grain Growth in Collapsing Clouds

    NASA Astrophysics Data System (ADS)

    Rossi, S. C. F.; Benevides-Soares, P.; Barbuy, B.

    1990-11-01

    RESUMEN. Se ha considerado un proceso de coagulaci6n de granos en nubes colapsantes de diferentes metalicidades. Se aplicaron los calculos al intervalo de densidades n = lO to , forrespondiendo a la fase isotermica de contracci6n de nubes. A lo largo de esta fase en el colap- so, la temperatura es por lo tanto constante, en donde se alcanza T Q lOKpara nubes de metalicidad solar y T 100 K para nubes de baja metalicidad. El tamano final del grano es mayor para las mayores metali- cidades. ABSTRACT. A process of grain coagulation in collapsing clouds of different metallicities is considered. The calculations are applied to the density range n = 1O to , corresponding to the isothermal phase of cloud contraction. Along this phase in the collapse, the temperature is thus a constant, where T % 10 K for solar-metallicity clouds, and T % 100 K for low metallicity clouds is reached. The final grain size is larger for the higher metallicities. Keq : INTERSTELLAR-CLOUDS - INTERSTELLAR-CRAINS

  20. Vortices of self-gravitating grains in dusty plasmas

    SciTech Connect

    Nebbat, E.; Annou, R.

    2012-09-15

    Vortices are an attractive expression of the non-linear dynamics of fluids along with plasmas. In complex plasmas, Nebbat and Annou [Phys. Plasmas 17, 093702 (2010)] proposed a time dependent non-linear model that considers vortices as a consequence of an instability. The model is augmented hereafter by incorporating the gravitational grain-grain attraction, particle drift due to self-gravity field, self-consistent inter-particle distance, the permeability of grains along with the grain charge excess due to the non-linear dependence of the grain capacitance on its size. Effects of the latter parameters as well as the effect of grain mass to charge ratio on the characteristics of the vortex such as density are investigated.

  1. Grains in galactic haloes

    NASA Technical Reports Server (NTRS)

    Ferrara, Andrea; Barsella, Bruno; Ferrini, F.; Greenberg, J. Mayo; Aiello, Santi

    1989-01-01

    Researchers considered the effect of extensive forces on dust grains subjected to the light and matter distribution of a spiral galaxy (Greenberg et al. (1987), Ferrini et al. (1987), Barsella et al (1988). Researchers showed that the combined force on a small particle located above the plane of a galactic disk may be either attractive or repulsive depending on a variety of parameters. They found, for example, that graphite grains from 20 nm to 250 nm radius are expelled from a typical galaxy, while silicates and other forms of dielectrics, after initial expulsion, may settle in potential minimum within the halo. They discuss only the statistical behavior of the forces for 17 galaxies whose luminosity and matter distribution in the disk, bulge and halo components are reasonably well known. The preliminary results of the study of the motion of a dust grain for NGC 3198 are given.

  2. Composite circumstellar dust grains

    NASA Astrophysics Data System (ADS)

    Gupta, Ranjan; Vaidya, Dipak B.; Dutta, Rajeshwari

    2016-10-01

    We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5-25 μm. We study the variation in absorption profiles with volume fractions of inclusions. In particular we study the variation in the wavelength of peak absorption at 10 and 18 μm. We also study the variation of the absorption of porous silicate grains. We use the absorption efficiencies to calculate the infrared flux at various dust temperatures and compare with the observed infrared emission flux from the circumstellar dust around some M-type and asymptotic giant branch stars obtained from IRAS and a few stars from Spitzer satellite. We interpret the observed data in terms of the circumstellar dust grain sizes, shape, composition and dust temperature.

  3. Grain quality inspection system

    NASA Technical Reports Server (NTRS)

    Flood, C. A., Jr.; Singletow, D. P.; James, S. N.

    1979-01-01

    A review of grain quality indicators and measurement methods was conducted in order to assess the feasibility of using remote sensing technology to develop a continuous monitoring system for use during grain transfer operations. Most detection methods were found to be too slow or too expensive to be incorporated into the normal inspection procedure of a grain elevator on a continuous basis. Two indicators, moisture content and broken corn and foreign material, show potential for automation and are of an economic value. A microprocessor based system which utilizes commercially available electronic moisture meter was developed and tested. A method for automating BCFM measurement is described. A complete system description is presented along with performance test results.

  4. Determination of grain size distribution function using two-dimensional Fourier transforms of tone pulse encoded images

    NASA Technical Reports Server (NTRS)

    Generazio, E. R.

    1986-01-01

    Microstructural images may be tone pulse encoded and subsequently Fourier transformed to determine the two-dimensional density of frequency components. A theory is developed relating the density of frequency components to the density of length components. The density of length components corresponds directly to the actual grain size distribution function from which the mean grain shape, size, and orientation can be obtained.

  5. A QSAR study of radical scavenging antioxidant activity of a series of flavonoids using DFT based quantum chemical descriptors--the importance of group frontier electron density.

    PubMed

    Sarkar, Ananda; Middya, Tapas Ranjan; Jana, Atish Dipnakar

    2012-06-01

    In a pursuit of electronic level understanding of the antioxidant activity of a series of flavonoids, quantitative structure-activity relationship (QSAR) studies have been carried out using density functional theory (DFT) based quantum chemical descriptors. The best QSAR model have been selected for which the computed square correlation coefficient r(2) = 0.937 and cross-validated squared correlation coefficient q(2) =0.916. The QSAR model indicates that hardness (η), group electrophilic frontier electron density (F(E)(A)) and group philicity (ω(B)(+)) of individual molecules are responsible for in vitro biological activity. To the best our knowledge, the group electrophilic frontier electron density (F(E)(A)) has been used for the first time to explain the radical scavenging activity (RSA) of flavonoids. The excellent correlation between the RSA and the above mentioned DFT based descriptors lead us to predict new antioxidants having very good antioxidant activity.

  6. Charging of interplanetary grains

    NASA Technical Reports Server (NTRS)

    Baragiola, R. A.; Johnson, R. E.; Newcomb, John L.

    1995-01-01

    The objective of this program is to quantify, by laboratory experiments, the charging of ices and other insulators subject to irradiation with electrons, ions and ultraviolet photons and to model special conditions based on the data. The system and conditions to be studied are those relevant for charging of dust in magnetospheric plasmas. The measurements are supplemented by computer simulations of charging or grains under a variety of conditions. Our work for this period involved experiments on water ice, improved models of charging of ice grains for Saturn's E-ring, and the construction of apparatus for electron impact studies and measurements of electron energy distributions.

  7. Radiative Grain Alignment

    NASA Astrophysics Data System (ADS)

    Andersson, B. G.

    2015-12-01

    Polarization due to aligned dust grains was discovered in the interstellar medium more than 60 years ago. A quantitative, observationally well tested theory of the phenomenon has finally emerged in the last decade, promising not only an improved understanding of interstellar magnetic fields, but new tools for studying the dust environments and grain characteristics. This Radiative Alignment Torque (RAT) theory also has many potential applications in solar system physics, including for comet dust characteristics. I will review the main aspects of the theory and the observational tests performed to date, as well as some of the new possibilities for using polarization as a tool to study dust and its environment, with RAT alignment.

  8. Grain optical properties

    NASA Technical Reports Server (NTRS)

    Hanner, Martha

    1988-01-01

    The optical properties of small grains provide the link between the infrared observations presented in Chapter 1 and the dust composition described in Chapter 3. In this session, the optical properties were discussed from the viewpoint of modeling the emission from the dust coma and the scattering in order to draw inference about the dust size distribution and composition. The optical properties are applied to the analysis of the infrared data in several ways, and these different uses should be kept in mind when judging the validity of the methods for applying optical constants to real grains.

  9. Elucidating the mechanism and active site of the cyclohexanol dehydrogenation on copper-based catalysts: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Wang, Ziyun; Liu, Xinyi; Rooney, D. W.; Hu, P.

    2015-10-01

    The dehydrogenation of cyclohexanol to cyclohexanone is very important in the manufacture of nylon. Copper-based catalysts are the most popular catalysts for this reaction, and on these catalysts the reaction mechanism and active site are in debate. In order to elucidate the mechanism and active site of the cyclohexanol dehydrogenation on copper-based catalysts, density functional theory with dispersion corrections were performed on up to six facets of copper in two different oxidation states: monovalent copper and metallic copper. By calculating the surface energies of these facets, Cu(111) and Cu2O(111) were found to be the most stable facets for metallic copper and for monovalent copper, respectively. On these two facets, all the possible elementary steps in the dehydrogenation pathway of cyclohexanol were calculated, including the adsorption, dehydrogenation, hydrogen coupling and desorption. Two different reaction pathways for dehydrogenation were considered on both surfaces. It was revealed that the dehydrogenation mechanisms are different on these two surfaces: on Cu(111) the hydrogen belonging to the hydroxyl is removed first, then the hydrogen belonging to the carbon is subtracted, while on Cu2O(111) the hydrogen belonging to the carbon is removed followed by the subtraction of the hydrogen in the hydroxyl group. Furthermore, by comparing the energy profiles of these two surfaces, Cu2O(111) was found to be more active for cyclohexanol dehydrogenation than Cu(111). In addition, we found that the coordinatively unsaturated copper sites on Cu2O(111) are the reaction sites for all the steps. Therefore, the coordinatively unsaturated copper site on Cu2O(111) is likely to be the active site for cyclohexanol dehydrogenation on the copper-based catalysts.

  10. Grain boundary curvature and grain growth kinetics with particle pinning

    NASA Astrophysics Data System (ADS)

    Shahandeh, Sina; Militzer, Matthias

    2013-08-01

    Second-phase particles are used extensively in design of polycrystalline materials to control the grain size. According to Zener's theory, a distribution of particles creates a pinning pressure on a moving grain boundary. As a result, a limiting grain size is observed, but the effect of pinning on the detail of grain growth kinetics is less known. The influence of the particles on the microstructure occurs in multiple length scales, established by particle radius and the grain size. In this article, we use a meso-scale phase-field model that simulates grain growth in the presence of a uniform pinning pressure. The curvature of the grain boundary network is measured to determine the driving pressure of grain growth in 2D and 3D systems. It was observed that the grain growth continues, even under conditions where the average driving pressure is smaller than the pinning pressure. The limiting grain size is reached when the maximum of driving pressure distribution in the structure is equal to the pinning pressure. This results in a limiting grain size, larger than the one predicted by conventional models, and further analysis shows consistency with experimental observations. A physical model is proposed for the kinetics of grain growth using parameters based on the curvature analysis of the grain boundaries. This model can describe the simulated grain growth kinetics.

  11. Risk of occupational allergy to stored grain arthropods and false pest-risk perception in Czech grain stores.

    PubMed

    Stejskal, Václav; Hubert, Jan

    2008-01-01

    Arthropods are a documented cause of occupational allergy in cereal stores. Since the current allergenic risk of various arthropods in grain stores is not known, we evaluated its extent using data from the Czech Republic (CZ). We surveyed 514 grain storage units for pest composition and density. Recalculating literature data we established 4 density dependent classes of pooled mite "allergy-risk level" (ARL) in stored grain: (i) safe-ARL: 0 mites.g(-1) grain, (ii) low-ARL: up to 1 mite.g(-1) grain, (iii) high-ARL: from 1 to 5 mites.g(-1) grain, (iv) danger-acute asthma-ARL: higher than 5 mites.g(-1) grain. Farmers (15) were questioned for pest taxon-related pesticide treatments. Mites constituted the largest group of collected pests (92%) followed by psocids (5%), beetles (3%) and moths (0%). 60% of mites belonged to known allergen producing species; the most abundant were Acarus siro, A. faris, Tyrophagus putrescentiae and Lepidoglyphus destructor. Grain samples belonged to the established ARL classes as follows: (i) safe-ARL: 37% (ii) low-ARL: 53%; (iii) high-ARL: 6%; (iv) danger-acute asthma-ARL: 4%. The enquiry among farmers revealed that almost no pesticides were targeted solely to control mites. This study suggests that mites represent, due to their allergenic potential, density and frequency, the most serious source of allergens in stored grain in CZ. However, the medical aspect of pest control--such as allergy avoidance strategy--is overlooked since grain feeding insects were mostly chemically controlled, regardless of their relatively low density and allergen production in comparison with mites.

  12. Effect of Heating Rate on Densification and Grain Growth During Spark Plasma Sintering of 93W-5.6Ni-1.4Fe Heavy Alloys

    NASA Astrophysics Data System (ADS)

    Hu, Ke; Li, Xiaoqiang; Qu, Shengguan; Li, Yuanyuan

    2013-09-01

    Blended 93W-5.6Ni-1.4Fe powders were sintered via the spark plasma sintering (SPS) technique using heating rates from 10 K min-1 to 380 K min-1 (10 °C min-1 to 380 °C min-1). The kinetics of densification and grain growth were analyzed to identify heating rate effects during the SPS of 93W-5.6Ni-1.4Fe powders. The activation energies for densification were calculated and compared with the experimental values for diffusion and other mass transport phenomena. The results show that for the slowly heated specimens [heating rate <100 K min-1 (100 °C min-1)], densification occurs mainly through dissolution-precipitation of W through the matrix phase and W grain boundary diffusion. The concurrent grain growth is dominated by surface diffusion at a low sintering temperature and by solution-reprecipitation and Ni-enhanced W grain boundary diffusion at a higher temperature. For the specimens sintered with heating rates higher than 100 K min-1 (100 °C min-1), the apparent activation energy value for the mechanism controlling densification is a strong function of the relative density, and fast densification controlled by multiple diffusion mechanisms and intensive viscous flow dominates over the grain growth. High SPS heating rate is favorable to obtain high density and fine-grained tungsten heavy alloys.

  13. Stored grain pack factors for wheat: comparison of three methods to field measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Storing grain in bulk storage units results in grain packing from overbearing pressure, which increases grain bulk density and storage-unit capacity. This study compared pack factors of hard red winter (HRW) wheat in vertical storage bins using different methods: the existing packing model (WPACKING...

  14. Bone mineral density changes after physical training and calcium intake in students with attention deficit and hyper activity disorders.

    PubMed

    Arab Ameri, Elahe; Dehkhoda, Mohammad Reza; Hemayattalab, Rasool

    2012-01-01

    In this study we investigate the effects of weight bearing exercise and calcium intake on bone mineral density (BMD) of students with attention deficit and hyper activity (ADHD) disorder. For this reason 54 male students with ADHD (age 8-12 years old) were assigned to four groups with no differences in age, BMD, calcium intake, and physical activity: exercise groups with or without calcium supplementation (Ex+Ca+ and Ex+Ca-) and non-exercise groups with or without calcium supplementation (Ex-Ca+ and Ex-Ca-). The intervention involved 50 min of weight bearing exercise performed 3 sessions a week and/or the addition of dietary calcium rich food using enriched cow milk with vitamin D containing 250 mg calcium per serving, over 9 months. Paired-samples t-test, one way ANOVA analysis, and Tukey tests were used to determine the main and combined effects of training and calcium on BMD. All groups showed greater femoral neck BMD after 9 months. The increase in femoral neck BMD was significantly different between all groups (p < 0.05). Ex+Ca+ group has greater increase in BMD than other groups. Apparently, the effect of training was greater than calcium intake (p < 0.05). These results help to provide more evidence for public health organizations to deal with both exercise and nutrition issues in children with ADHD disorder for the achievement of peak BMD.

  15. A New Route of Fucoidan Immobilization on Low Density Polyethylene and Its Blood Compatibility and Anticoagulation Activity

    PubMed Central

    Ozaltin, Kadir; Lehocký, Marián; Humpolíček, Petr; Pelková, Jana; Sáha, Petr

    2016-01-01

    Beside biomaterials’ bulk properties, their surface properties are equally important to control interfacial biocompatibility. However, due to the inadequate interaction with tissue, they may cause foreign body reaction. Moreover, surface induced thrombosis can occur when biomaterials are used for blood containing applications. Surface modification of the biomaterials can bring enhanced surface properties in biomedical applications. Sulfated polysaccharide coatings can be used to avoid surface induced thrombosis which may cause vascular occlusion (blocking the blood flow by blood clot), which results in serious health problems. Naturally occurring heparin is one of the sulfated polysaccharides most commonly used as an anticoagulant, but its long term usage causes hemorrhage. Marine sourced sulfated polysaccharide fucoidan is an alternative anticoagulant without the hemorrhage drawback. Heparin and fucoidan immobilization onto a low density polyethylene surface after functionalization by plasma has been studied. Surface energy was demonstrated by water contact angle test and chemical characterizations were carried out by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Surface morphology was monitored by scanning electron microscope and atomic force microscope. Finally, their anticoagulation activity was examined for prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin time (TT). PMID:27294915

  16. A New Route of Fucoidan Immobilization on Low Density Polyethylene and Its Blood Compatibility and Anticoagulation Activity.

    PubMed

    Ozaltin, Kadir; Lehocký, Marián; Humpolíček, Petr; Pelková, Jana; Sáha, Petr

    2016-01-01

    Beside biomaterials' bulk properties, their surface properties are equally important to control interfacial biocompatibility. However, due to the inadequate interaction with tissue, they may cause foreign body reaction. Moreover, surface induced thrombosis can occur when biomaterials are used for blood containing applications. Surface modification of the biomaterials can bring enhanced surface properties in biomedical applications. Sulfated polysaccharide coatings can be used to avoid surface induced thrombosis which may cause vascular occlusion (blocking the blood flow by blood clot), which results in serious health problems. Naturally occurring heparin is one of the sulfated polysaccharides most commonly used as an anticoagulant, but its long term usage causes hemorrhage. Marine sourced sulfated polysaccharide fucoidan is an alternative anticoagulant without the hemorrhage drawback. Heparin and fucoidan immobilization onto a low density polyethylene surface after functionalization by plasma has been studied. Surface energy was demonstrated by water contact angle test and chemical characterizations were carried out by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Surface morphology was monitored by scanning electron microscope and atomic force microscope. Finally, their anticoagulation activity was examined for prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin time (TT). PMID:27294915

  17. Bone mineral density changes after physical training and calcium intake in students with attention deficit and hyper activity disorders.

    PubMed

    Arab Ameri, Elahe; Dehkhoda, Mohammad Reza; Hemayattalab, Rasool

    2012-01-01

    In this study we investigate the effects of weight bearing exercise and calcium intake on bone mineral density (BMD) of students with attention deficit and hyper activity (ADHD) disorder. For this reason 54 male students with ADHD (age 8-12 years old) were assigned to four groups with no differences in age, BMD, calcium intake, and physical activity: exercise groups with or without calcium supplementation (Ex+Ca+ and Ex+Ca-) and non-exercise groups with or without calcium supplementation (Ex-Ca+ and Ex-Ca-). The intervention involved 50 min of weight bearing exercise performed 3 sessions a week and/or the addition of dietary calcium rich food using enriched cow milk with vitamin D containing 250 mg calcium per serving, over 9 months. Paired-samples t-test, one way ANOVA analysis, and Tukey tests were used to determine the main and combined effects of training and calcium on BMD. All groups showed greater femoral neck BMD after 9 months. The increase in femoral neck BMD was significantly different between all groups (p < 0.05). Ex+Ca+ group has greater increase in BMD than other groups. Apparently, the effect of training was greater than calcium intake (p < 0.05). These results help to provide more evidence for public health organizations to deal with both exercise and nutrition issues in children with ADHD disorder for the achievement of peak BMD. PMID:22155532

  18. Can we define an asymptotic value for the ice active surface site density for heterogeneous ice nucleation?

    NASA Astrophysics Data System (ADS)

    Niedermeier, Dennis; Augustin-Bauditz, Stefanie; Hartmann, Susan; Wex, Heike; Ignatius, Karoliina; Stratmann, Frank

    2015-04-01

    The formation of ice in atmospheric clouds has a substantial influence on the radiative properties of clouds as well as on the formation of precipitation. Therefore much effort has been made to understand and quantify the major ice formation processes in clouds. Immersion freezing has been suggested to be a dominant primary ice formation process in low and mid-level clouds (mixed-phase cloud conditions). It also has been shown that mineral dust particles are the most abundant ice nucleating particles in the atmosphere and thus may play an important role for atmospheric ice nucleation (Murray et al., 2012). Additionally, biological particles like bacteria and pollen are suggested to be potentially involved in atmospheric ice formation, at least on a regional scale (Murray et al., 2012). In recent studies for biological particles (SNOMAX and birch pollen), it has been demonstrated that freezing is induced by ice nucleating macromolecules and that an asymptotic value for the mass density of these ice nucleating macromolecules can be determined (Hartmann et al., 2013; Augustin et al., 2013, Wex et al., 2014). The question arises whether such an asymptotic value can also be determined for the ice active surface site density ns, a parameter which is commonly used to describe the ice nucleation activity of e.g., mineral dust. Such an asymptotic value for ns could be an important input parameter for atmospheric modeling applications. In the presented study, we therefore investigated the immersion freezing behavior of droplets containing size-segregated, monodisperse feldspar particles utilizing the Leipzig Aerosol Cloud Interaction Simulator (LACIS). For all particle sizes considered in the experiments, we observed a leveling off of the frozen droplet fraction reaching a plateau within the heterogeneous freezing temperature regime (T > -38°C) which was proportional to the particle surface area. Based on these findings, we could determine an asymptotic value for the ice

  19. Wheat Grain Development Is Characterized by Remarkable Trehalose 6-Phosphate Accumulation Pregrain Filling: Tissue Distribution and Relationship to SNF1-Related Protein Kinase1 Activity1[W][OA

    PubMed Central

    Martínez-Barajas, Eleazar; Delatte, Thierry; Schluepmann, Henriette; de Jong, Gerhardus J.; Somsen, Govert W.; Nunes, Cátia; Primavesi, Lucia F.; Coello, Patricia; Mitchell, Rowan A.C.; Paul, Matthew J.

    2011-01-01

    Trehalose 6-phosphate (T6P) is a sugar signal that regulates metabolism, growth, and development and inhibits the central regulatory SNF1-related protein kinase1 (SnRK1; AKIN10/AKIN11). To better understand the mechanism in wheat (Triticum aestivum) grain, we analyze T6P content and SnRK1 activities. T6P levels changed 178-fold 1 to 45 d after anthesis (DAA), correlating with sucrose content. T6P ranged from 78 nmol g−1 fresh weight (FW) pregrain filling, around 100-fold higher than previously reported in plants, to 0.4 nmol g−1 FW during the desiccation stage. In contrast, maximum SnRK1 activity changed only 3-fold but was inhibited strongly by T6P in vitro. To assess SnRK1 activity in vivo, homologs of SnRK1 marker genes in the wheat transcriptome were identified using Wheat Estimated Transcript Server. SnRK1-induced and -repressed marker genes were expressed differently pregrain filling compared to grain filling consistent with changes in T6P. To investigate this further maternal and filial tissues were compared pre- (7 DAA) and during grain filling (17 DAA). Strikingly, in vitro SnRK1 activity was similar in all tissues in contrast to large changes in tissue distribution of T6P. At 7 DAA T6P was 49 to 119 nmol g−1 FW in filial and maternal tissues sufficient to inhibit SnRK1; at 17 DAA T6P accumulation was almost exclusively endospermal (43 nmol g−1 FW) with 0.6 to 0.8 nmol T6P g−1 FW in embryo and pericarp. The data show a correlation between T6P and sucrose overall that belies a marked effect of tissue type and developmental stage on T6P content, consistent with tissue-specific regulation of SnRK1 by T6P in wheat grain. PMID:21402798

  20. Edible grain legumes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Edible grain legumes including dry bean, dry pea, chickpeas, and lentils, have served as important sources of protein for human diets for thousands of years. In the US, these crops are predominately produced for export markets. The objective of this study was to examine yield gains in these crops ov...

  1. A Dastardly Density Deed.

    ERIC Educational Resources Information Center

    Shaw, Mike

    2003-01-01

    Integrates story telling into a science activity on the density of liquids in order to increase student interest. Shows the relationship between mass and volume ratio and how they determine density. Includes teacher notes. (YDS)