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Sample records for surface potential increases

  1. Lunar Surface Potential Increases during Terrestrial Bow Shock Traversals

    Science.gov (United States)

    Collier, Michael R.; Stubbs, Timothy J.; Hills, H. Kent; Halekas, Jasper; Farrell, William M.; Delory, Greg T.; Espley, Jared; Freeman, John W.; Vondrak, Richard R.; Kasper, Justin

    2009-01-01

    Since the Apollo era the electric potential of the Moon has been a subject of interest and debate. Deployed by three Apollo missions, Apollo 12, Apollo 14 and Apollo 15, the Suprathermal Ion Detector Experiment (SIDE) determined the sunlit lunar surface potential to be about +10 Volts using the energy spectra of lunar ionospheric thermal ions accelerated toward the Moon. We present an analysis of Apollo 14 SIDE "resonance" events that indicate the lunar surface potential increases when the Moon traverses the dawn bow shock. By analyzing Wind spacecraft crossings of the terrestrial bow shock at approximately this location and employing current balancing models of the lunar surface, we suggest causes for the increasing potential. Determining the origin of this phenomenon will improve our ability to predict the lunar surface potential in support of human exploration as well as provide models for the behavior of other airless bodies when they traverse similar features such as interplanetary shocks, both of which are goals of the NASA Lunar Science Institute's Dynamic Response of the Environment At the Moon (DREAM) team.

  2. Potential photosynthesis of crop surfaces.

    NARCIS (Netherlands)

    Wit, de C.T.

    1959-01-01

    A formula for calculating the potential photosynthesis of a closed crop surface is proposed, assuming that the leaves of the crop are not arranged in any definite direction. In the Netherlands, values for potential photosynthesis vary from 290 kg. CH2O/ha./day in June to 50 kg./ha./day in December.

  3. Scanning Surface Potential Microscopy of Spore Adhesion on Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ida [University of Tennessee, Knoxville (UTK); Chung, Eunhyea [Georgia Institute of Technology; Kweon, Hyojin [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Tsouris, Costas [ORNL

    2012-01-01

    The adhesion of spores of Bacillus anthracis - the cause of anthrax and a likely biological threat - to solid surfaces is an important consideration in cleanup after an accidental or deliberate release. However, because of safety concerns, directly studying B. anthracis spores with advanced instrumentation is problematic. As a first step, we are examining the electrostatic potential of Bacillus thuringiensis (Bt), which is a closely related species that is often used as a simulant to study B. anthracis. Scanning surface potential microscopy (SSPM), also known as Kelvin probe force microscopy (KPFM), was used to investigate the influence of relative humidity (RH) on the surface electrostatic potential of Bt that had adhered to silica, mica, or gold substrates. AFM/SSPM side-by-side images were obtained separately in air, at various values of RH, after an aqueous droplet with spores was applied on each surface and allowed to dry before measurements. In the SSPM images, a negative potential on the surface of the spores was observed compared with that of the substrates. The surface potential decreased as the humidity increased. Spores were unable to adhere to a surface with an extremely negative potential, such as mica.

  4. Scanning surface potential microscopy of spore adhesion on surfaces.

    Science.gov (United States)

    Lee, I; Chung, E; Kweon, H; Yiacoumi, S; Tsouris, C

    2012-04-01

    The adhesion of spores of Bacillus anthracis - the cause of anthrax and a likely biological threat - to solid surfaces is an important consideration in cleanup after an accidental or deliberate release. However, because of safety concerns, directly studying B. anthracis spores with advanced instrumentation is problematic. As a first step, we are examining the electrostatic potential of Bacillus thuringiensis (Bt), which is a closely related species that is often used as a simulant to study B. anthracis. Scanning surface potential microscopy (SSPM), also known as Kelvin probe force microscopy (KPFM), was used to investigate the influence of relative humidity (RH) on the surface electrostatic potential of Bt that had adhered to silica, mica, or gold substrates. AFM/SSPM side-by-side images were obtained separately in air, at various values of RH, after an aqueous droplet with spores was applied on each surface and allowed to dry before measurements. In the SSPM images, a negative potential on the surface of the spores was observed compared with that of the substrates. The surface potential decreased as the humidity increased. Spores were unable to adhere to a surface with an extremely negative potential, such as mica. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Increasing persistent haze in Beijing: potential impacts of weakening East Asian winter monsoons associated with northwestern Pacific sea surface temperature trends

    Science.gov (United States)

    Pei, Lin; Yan, Zhongwei; Sun, Zhaobin; Miao, Shiguang; Yao, Yao

    2018-03-01

    Over the past decades, Beijing, the capital city of China, has encountered increasingly frequent persistent haze events (PHE). While the increased pollutant emissions are considered as the most important reason, changes in regional atmospheric circulations associated with large-scale climate warming also play a role. In this study, we find a significant positive trend of PHE in Beijing for the winters from 1980 to 2016 based on updated daily observations. This trend is closely related to an increasing frequency of extreme anomalous southerly episodes in North China, a weakened East Asian trough in the mid-troposphere and a northward shift of the East Asian jet stream in the upper troposphere. These conditions together depict a weakened East Asian winter monsoon (EAWM) system, which is then found to be associated with an anomalous warm, high-pressure system in the middle-lower troposphere over the northwestern Pacific. A practical EAWM index is defined as the seasonal meridional wind anomaly at 850 hPa in winter over North China. Over the period 1900-2016, this EAWM index is positively correlated with the sea surface temperature anomalies over the northwestern Pacific, which indicates a wavy positive trend, with an enhanced positive phase since the mid-1980s. Our results suggest an observation-based mechanism linking the increase in PHE in Beijing with large-scale climatic warming through changes in the typical regional atmospheric circulation.

  6. Altmetric: 165More detailArticle | OPENClimate change-induced increases in precipitation are reducing the potential for solar ultraviolet radiation to inactivate pathogens in surface waters

    Science.gov (United States)

    Climate change is accelerating the release of dissolved organic matter (DOM) to inland and coastal waters through increases in precipitation, thawing of permafrost, and changes in vegetation. Our modeling approach suggests that the selective absorption of ultraviolet radiation (U...

  7. Potential energy surfaces for chemical reactions

    International Nuclear Information System (INIS)

    Schaefer, H.F. III.

    1976-01-01

    Research into potential energy surfaces for chemical reactions at Lawrence Berkeley Laboratory during 1976 is described. Topics covered include: the fuzzy interface between surface chemistry catalysis and organometallic chemistry; potential energy surfaces for elementary fluorine hydrogen reactions; structure, energetics, and reactivity of carbenes; and the theory of self-consistent electron pairs

  8. Atom-surface potentials and atom interferometry

    International Nuclear Information System (INIS)

    Babb, J.F.

    1998-01-01

    Long-range atom-surface potentials characterize the physics of many actual systems and are now measurable spectroscopically in deflection of atomic beams in cavities or in reflection of atoms in atomic fountains. For a ground state, spherically symmetric atom the potential varies as -1/R 3 near the wall, where R is the atom-surface distance. For asymptotically large distances the potential is weaker and goes as -1/R 4 due to retardation arising from the finite speed of light. This diminished interaction can also be interpreted as a Casimir effect. The possibility of measuring atom-surface potentials using atomic interferometry is explored. The particular cases studied are the interactions of a ground-state alkali-metal atom and a dielectric or a conducting wall. Accurate descriptions of atom-surface potentials in theories of evanescent-wave atomic mirrors and evanescent wave-guided atoms are also discussed. (author)

  9. Potential transgenic routes to increase tree biomass.

    Science.gov (United States)

    Dubouzet, Joseph G; Strabala, Timothy J; Wagner, Armin

    2013-11-01

    Biomass is a prime target for genetic engineering in forestry because increased biomass yield will benefit most downstream applications such as timber, fiber, pulp, paper, and bioenergy production. Transgenesis can increase biomass by improving resource acquisition and product utilization and by enhancing competitive ability for solar energy, water, and mineral nutrients. Transgenes that affect juvenility, winter dormancy, and flowering have been shown to influence biomass as well. Transgenic approaches have increased yield potential by mitigating the adverse effects of prevailing stress factors in the environment. Simultaneous introduction of multiple genes for resistance to various stress factors into trees may help forest trees cope with multiple or changing environments. We propose multi-trait engineering for tree crops, simultaneously deploying multiple independent genes to address a set of genetically uncorrelated traits that are important for crop improvement. This strategy increases the probability of unpredictable (synergistic or detrimental) interactions that may substantially affect the overall phenotype and its long-term performance. The very limited ability to predict the physiological processes that may be impacted by such a strategy requires vigilance and care during implementation. Hence, we recommend close monitoring of the resultant transgenic genotypes in multi-year, multi-location field trials. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  10. Computed potential energy surfaces for chemical reactions

    Science.gov (United States)

    Walch, Stephen P.; Levin, Eugene

    1993-01-01

    A new global potential energy surface (PES) is being generated for O(P-3) + H2 yields OH + H. This surface is being fit using the rotated Morse oscillator method, which was used to fit the previous POL-CI surface. The new surface is expected to be more accurate and also includes a much more complete sampling of bent geometries. A new study has been undertaken of the reaction N + O2 yields NO + O. The new studies have focused on the region of the surface near a possible minimum corresponding to the peroxy form of NOO. A large portion of the PES for this second reaction has been mapped out. Since state to state cross sections for the reaction are important in the chemistry of high temperature air, these studies will probably be extended to permit generation of a new global potential for reaction.

  11. Potential energy surface of alanine polypeptide chains

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Yakubovich, Alexander V.; Solov'yov, Andrey V.

    2006-01-01

    The multidimensional potential energy surfaces of the peptide chains consisting of three and six alanine (Ala) residues have been studied with respect to the degrees of freedom related to the twist of these molecules relative to the peptide backbone (these degrees of freedom are responsible...

  12. Computed potential energy surfaces for chemical reactions

    Science.gov (United States)

    Walch, Stephen P.

    1994-01-01

    Quantum mechanical methods have been used to compute potential energy surfaces for chemical reactions. The reactions studied were among those believed to be important to the NASP and HSR programs and included the recombination of two H atoms with several different third bodies; the reactions in the thermal Zeldovich mechanism; the reactions of H atom with O2, N2, and NO; reactions involved in the thermal De-NO(x) process; and the reaction of CH(squared Pi) with N2 (leading to 'prompt NO'). These potential energy surfaces have been used to compute reaction rate constants and rates of unimolecular decomposition. An additional application was the calculation of transport properties of gases using a semiclassical approximation (and in the case of interactions involving hydrogen inclusion of quantum mechanical effects).

  13. Potential energy surface of triplet O4.

    Science.gov (United States)

    Paukku, Yuliya; Varga, Zoltan; Truhlar, Donald G

    2018-03-28

    We present a global ground-state potential energy surface (PES) for the triplet spin state of O 4 that is suitable for treating high-energy vibrational-rotational energy transfer and collision-induced dissociation in electronically adiabatic spin-conserving O 2 -O 2 collisions. The surface is based on MS-CASPT2/maug-cc-pVTZ electronic structure calculations with scaled external correlation; the active space has 16 electrons in 12 orbitals. The global ground-state potential energy surface was fitted by a many-body approach with an accurate O-O pairwise interaction and a fit of the many-body interaction potential to 10 180 electronic structure data points. The many-body fit is based on permutationally invariant polynomials in terms of bond-order functions of the six interatomic distances; the bond-order functions are mixed exponential-Gaussian functions. The geometries calculated and used for the fit include geometry scans corresponding to dissociative and vibrationally excited diatom-diatom collisions of O 2 , scans corresponding to O 3 interacting with O, additional geometries identified by running trajectories, and geometries along linear synchronous transit paths connecting randomly selected points. The global O 4 PES includes subsurfaces describing the interaction of diatomic molecules with other diatomic molecules or interactions of triatomic molecules and an atom. The interaction of ozone with a ground-state oxygen atom occurs on the triplet O 4 surface, and our surface includes high-energy points with O 3 -O geometries as well as O 2 -O 2 geometries and O 2 -O-O geometries.

  14. Potential utility of the thematic mapper for surface mine monitoring

    International Nuclear Information System (INIS)

    Irons, J.R.; Lachowski, H.M.

    1981-01-01

    One of many potential applications of the thematic mapper (TM) is surface mine monitoring. To assess this potential, data acquired by an aircraft multispectral scanner over Pennsylvania surface mines were preprocessed to simulate the anticipated spectral, spatial, and radiometric characteristics of TM data. False color imagery and thematic maps were derived from the simulated data and compared to imagery and maps derived from LANDSAT multispectral scanner subsystems data. On the basis of this comparison, TM data should definitely increase the detail and accuracy of remotely acquired surface mine information and may enable the remote determination of compliance with reclamation regulations

  15. Osteogenic potential of laser modified and conditioned titanium zirconium surfaces

    Directory of Open Access Journals (Sweden)

    P David Charles

    2016-01-01

    Full Text Available Statement of Problem: The osseointegration of dental implant is related to their composition and surface treatment. Titanium zirconium (TiZr has been introduced as an alternative to the commercially pure titanium and its alloys as dental implant material, which is attributed to its superior mechanical and biological properties. Surface treatments of TiZr have been introduced to enhance their osseointegration ability; however, reliable, easy to use surface modification technique has not been established. Purpose: The purpose of this study was to evaluate and compare the effect of neodymium-doped yttrium aluminum garnet (Nd-YAG laser surface treatment of TiZr implant alloy on their osteogenic potential. Materials and Methods: Twenty disc-shaped samples of 5 mm diameter and 2 mm height were milled from the TiZr alloy ingot. The polished discs were ultrasonically cleaned in distilled water. Ten samples each were randomly selected as Group A control samples and Group B consisted of Nd-YAG laser surface etched and conditioned test samples. These were evaluated for cellular response. Cellular adhesion and proliferation were quantified, and the results were statistically analyzed using nonparametric analysis. Cellular morphology was observed using electron and epiflurosence microscopy. Results: Nd-YAG laser surface modified and conditioned TiZr samples increased the osteogenic potential. Conclusion: Nd-YAG laser surface modification of TiZr, improves the cellular activity, surface roughness, and wettability, thereby increasing the osteogenic potential.

  16. Theoretical studies of potential energy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Harding, L.B. [Argonne National Laboratory, IL (United States)

    1993-12-01

    The goal of this program is to calculate accurate potential energy surfaces (PES) for both reactive and nonreactive systems. To do this the electronic Schrodinger equation must be solved. Our approach to this problem starts with multiconfiguration self-consistent field (MCSCF) reference wavefunctions. These reference wavefunctions are designed to be sufficiently flexible to accurately describe changes in electronic structure over a broad range of geometries. Electron correlation effects are included via multireference, singles and doubles configuration interaction (MRSDCI) calculations. With this approach, the authors are able to provide useful predictions of the energetics for a broad range of systems.

  17. Energy conservation potential of surface modification technologies

    Energy Technology Data Exchange (ETDEWEB)

    Le, H.K.; Horne, D.M.; Silberglitt, R.S.

    1985-09-01

    This report assesses the energy conservation impact of surface modification technologies on the metalworking industries. The energy conservation impact of surface modification technologies on the metalworking industries is assessed by estimating their friction and wear tribological sinks and the subsequent reduction in these sinks when surface modified tools are used. Ion implantation, coatings, and laser and electron beam surface modifications are considered.

  18. Homogenization mechanism of the residual surface potential of insulating specimens under electron beam irradiation

    International Nuclear Information System (INIS)

    Li Jingjing; Zhang Haibo; Feng Renjian

    2007-01-01

    A homogenized surface potential is desirable for the observation of a pre-irradiated insulating specimen using a scanning electron microscope because the residual surface potential may affect the imaging properties of the specimen. To homogenize the residual surface potential, the specimen should be subjected to the irradiation of an electron beam with the total electron yield greater than one. The expression of the equilibrium potential is derived based on the charge balance condition in the equilibrium state and the potential value is found to increase mainly with the secondary electron (SE) yield and the most probable emission energy of SEs. Further numerical calculations of SE trajectories show that affected by different surface potentials, SEs leave or return to the specimen surface to change the net charge flux into the specimen. This thereby increases the surface potential below the equilibrium potential and decreases that above the equilibrium potential, homogenizing the surface potential

  19. Increased Surface Wind Speeds Follow Diminishing Arctic Sea Ice

    Science.gov (United States)

    Mioduszewski, J.; Vavrus, S. J.; Wang, M.; Holland, M. M.; Landrum, L.

    2017-12-01

    Projections of Arctic sea ice through the end of the 21st century indicate the likelihood of a strong reduction in ice area and thickness in all seasons, leading to a substantial thermodynamic influence on the overlying atmosphere. This is likely to have an effect on winds over the Arctic Basin, due to changes in atmospheric stability and/or baroclinicity. Prior research on future Arctic wind changes is limited and has focused mainly on the practical impacts on wave heights in certain seasons. Here we attempt to identify patterns and likely mechanisms responsible for surface wind changes in all seasons across the Arctic, particularly those associated with sea ice loss in the marginal ice zone. Sea level pressure, near-surface (10 m) and upper-air (850 hPa) wind speeds, and lower-level dynamic and thermodynamic variables from the Community Earth System Model Large Ensemble Project (CESM-LE) were analyzed for the periods 1971-2000 and 2071-2100 to facilitate comparison between a present-day and future climate. Mean near-surface wind speeds over the Arctic Ocean are projected to increase by late century in all seasons but especially during autumn and winter, when they strengthen by up to 50% locally. The most extreme wind speeds in the 90th percentile change even more, increasing in frequency by over 100%. The strengthened winds are closely linked to decreasing lower-tropospheric stability resulting from the loss of sea ice cover and consequent surface warming (locally over 20 ºC warmer in autumn and winter). A muted pattern of these future changes is simulated in CESM-LE historical runs from 1920-2005. The enhanced winds near the surface are mostly collocated with weaker winds above the boundary layer during autumn and winter, implying more vigorous vertical mixing and a drawdown of high-momentum air.The implications of stronger future winds include increased coastal hazards and the potential for a positive feedback with sea ice by generating higher winds and

  20. Computed potential energy surfaces for chemical reactions

    Science.gov (United States)

    Walch, Stephen P.

    1988-01-01

    The minimum energy path for the addition of a hydrogen atom to N2 is characterized in CASSCF/CCI calculations using the (4s3p2d1f/3s2p1d) basis set, with additional single point calculations at the stationary points of the potential energy surface using the (5s4p3d2f/4s3p2d) basis set. These calculations represent the most extensive set of ab initio calculations completed to date, yielding a zero point corrected barrier for HN2 dissociation of approx. 8.5 kcal mol/1. The lifetime of the HN2 species is estimated from the calculated geometries and energetics using both conventional Transition State Theory and a method which utilizes an Eckart barrier to compute one dimensional quantum mechanical tunneling effects. It is concluded that the lifetime of the HN2 species is very short, greatly limiting its role in both termolecular recombination reactions and combustion processes.

  1. Constructing ab initio and empirical potential energy surfaces for water

    International Nuclear Information System (INIS)

    Kain, Jacqueline Sophie

    2001-01-01

    The infrared spectrum of water is possibly one of the most well studied and yet portions of it are still poorly understood. Recently, significant advances have been made in assigning water spectra using variational nuclear calculations. The major factor determining the accuracy of ro-vibrational spectra of water is the accuracy of the underlying Potential Energy Surface. Even the most accurate ab initio Potential Energy Surface does not reproduce the Born-Oppenheimer surface to sufficient accuracy for spectroscopic studies. Furthermore, effects beyond this model such as the adiabatic correction, the relativistic correction and the non-adiabatic correction have to be considered. This thesis includes a discussion on how the relativistic correction was calculated, for the water molecule, from first-order perturbation theory. The relativistic correction improved vibrational stretching motion while making the prediction of the bending modes far worse. For rotational motion the relativistic effect had an increasing effect with increasing Ka. A further alteration to the ab initio calculations is introduced by adjusting the barrier to linearity in the water potential. This alteration to the barrier was considered in order to compensate for the lack of convergence of quantum chemical calculations of the Born-Oppenheimer surface. This barrier attempts to represent the change in the potential from linear to equilibrium. We show the improvements this has on the calculated energy levels by comparison with the HITRAN database. This then led the way to the improved spectroscopic potential presented here in this thesis. This new spectroscopic potential reduces the overall standard deviation significantly for vibrational and rotational energy levels. (author)

  2. Urban Surfaces and Heat Island Mitigation Potentials

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Akbari, Hashem; Shea Rose, Leanna

    2007-06-14

    Data on materials and surface types that comprise a city, i.e. urban fabric, are needed in order to estimate the effects of light-colored surfaces (roofs and pavements) and urban vegetation (trees, grass, shrubs) on the meteorology and air quality of a city. We discuss the results of a semi-automatic statistical approach used to develop data on surface-type distribution and urban-fabric makeup using aerial color orthophotography, for four metropolitan areas of Chicago, IL, Houston, TX, Sacramento, CA, and Salt Lake City, UT. The digital high resolution (0.3 to 0.5-m) aerial photographs for each of these metropolitan areas covers representative urban areas ranging from 30 km{sup 2} to 52 km{sup 2}. Major land-use types examined included: commercial, residential, industrial, educational, and transportation. On average, for the metropolitan areas studied, vegetation covers about 29-41% of the area, roofs 19-25%, and paved surfaces 29-39%. For the most part, trees shade streets, parking lots, grass, and sidewalks. At ground level, i.e., view from below the tree canopies, vegetation covers about 20-37% of the area, roofs 20-25%, and paved surfaces 29-36%.

  3. Increased Biocompatibility and Bioactivity after Energetic PVD Surface Treatments

    Directory of Open Access Journals (Sweden)

    Stephan Mändl

    2009-09-01

    Full Text Available Ion implantation, a common technology in semiconductor processing, has been applied to biomaterials since the 1960s. Using energetic ion bombardment, a general term which includes conventional ion implantation plasma immersion ion implantation (PIII and ion beam assisted thin film deposition, functionalization of surfaces is possible. By varying and adjusting the process parameters, several surface properties can be attuned simultaneously. Extensive research details improvements in the biocompatibility, mainly by reducing corrosion rates and increasing wear resistance after surface modification. Recently, enhanced bioactivity strongly correlated with the surface topography and less with the surface chemistry has been reported, with an increased roughness on the nanometer scale induced by self-organisation processes during ion bombardment leading to faster cellular adhesion processes.

  4. Frequency response in surface-potential driven electrohydrodynamics

    DEFF Research Database (Denmark)

    Ejsing, Louise Wellendorph; Smistrup, Kristian; Pedersen, Christian Møller

    2006-01-01

    capacitance where the net flow rate is, in general, zero while harmonic rolls as well as time-averaged vortexlike components may exist depending on the spatial symmetry and extension of the surface potential. In general, the system displays a resonance behavior at a frequency corresponding to the inverse RC...... time of the system. Different surface potentials share the common feature that the resonance frequency is inversely proportional to the characteristic length scale of the surface potential. For the asymptotic frequency dependence above resonance we find a omega(-2) power law for surface potentials...

  5. In vitro studies on the cytotoxic potential of surface sealants.

    Science.gov (United States)

    Zingler, S; Matthei, B; Kohl, A; Saure, D; Ludwig, B; Diercke, K; Lux, C J; Erber, R

    2015-01-01

    The objective of this in vitro study was an initial screening of the cytotoxic potential of widely used smooth enamel surface sealants. A total of 20 products were allocated to four groups based on their chemical composition: (1) filled resin-based sealants, (2) unfilled resin-based sealants, (3) a resin-modified, glass ionomer-based sealant, and (4) silicone-based sealants. All materials were applied to human enamel slices both in accordance with manufacturers' instructions and in additional experiments applying 50% undercuring and 50% overcuring. An agar overlay assay was then used to test the specimens following ISO 10933. The cytotoxic potential of each material was interpreted based on a reaction index that summarized the decolorization and lysis scores obtained. The cytotoxic potential decreased as follows: unfilled resin-based sealants > filled resin-based sealants > resin-modified, glass ionomer-based sealant > silicone-based sealants. In 75% of the resin-based products, deliberate undercuring was associated with more extensive decolorization zones, leading to higher rates of cytotoxic potential in two of those products. Overcuring, by contrast, was associated with a tendency for smaller decolorization zones in 50% of the resin-based products. Surface sealants derived from resin monomers exhibited cytotoxic potential in the agar overlay assay. There is also evidence of a possible association with curing, as undercuring can increase the cytotoxic potential, whereas normal curing (as per manufacturers' instructions) or overcuring may help minimize such effects. More research into the biological implications of these materials is needed, especially with regard to their potential impact on the adjacent gingiva.

  6. Bernoulli potential at a superconductor surface

    Czech Academy of Sciences Publication Activity Database

    Lipavský, Pavel; Koláček, Jan; Mareš, Jiří J.; Morawetz, K.

    2001-01-01

    Roč. 65, - (2001), s. 012507-1-012507-3 ISSN 0163-1829 R&D Projects: GA ČR GA202/00/0643; GA ČR GA202/99/0410; GA AV ČR IAA1010806; GA AV ČR IAA1010919 Institutional research plan: CEZ:AV0Z1010914 Keywords : Hall effect * Bernoulli potential Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.070, year: 2001

  7. Investigation of zones with increased ground surface gamma radiation

    International Nuclear Information System (INIS)

    Butkus, D.V.; Morkunas, G.S.; Styro, B.I.

    1989-01-01

    Measurements of the increased gamma radiation zones of soils were conducted in the South-Western part of the Litvinian. The shores of lakes in the north-eastern part of the Suduva high land were investigated. the maximum values of the gamma radiation dose rates were distributed along the lake shores at a distance of 1 m from the water surface, while farther than 1.5 m from it the dose rate was close to the natural value. The increased gamma radiation intensity zones on the ground surface were found only at the northern (Lake Reketija) or the western shore (other lakes under investigation). The highest values of the gamma radiation dose 200-600 μR/h (0.5-1.5 nGy/s) were observed in the comparatively small areas (up to several square metres). The gamma radiation intensity of soil surface increased strongly moving towards the point where the maximum intensity was obsered. 10 figs

  8. The electric potential of the lunar surface

    Science.gov (United States)

    Fenner, M. A.; Freeman, J. W., Jr.; Hills, H. K.

    1973-01-01

    Acceleration and detection of the lunar thermal ionosphere in the presence of the lunar electric field yields a value of at least +10 V for the lunar electric potential for solar zenith angles between approximately 20 and 45 deg and in the magnetosheath or solar wind. An enhanced positive ion flux is observed with the ALSEP Suprathermal Ion Detector when a pre-acceleration voltage attains certain values. This enhancement is greater when the moon is in the solar wind as opposed to the magnetosheath.

  9. Lunar electric fields, surface potential and associated plasma sheaths

    Science.gov (United States)

    Freeman, J. W.; Ibrahim, M.

    1975-01-01

    A review is given of studies of the electric-field environment of the moon. Surface electric potentials are reported for the dayside and terminator regions, electron and ion densities in the plasma sheath adjacent to each surface-potential regime are evaluated, and the corresponding Debye lengths are estimated. The electric fields, which are approximated by the surface potential over the Debye length, are shown to be at least three orders of magnitude higher than the pervasive solar-wind electric field and to be confined to within a few tens of meters of the lunar surface.

  10. Green's functions potential fields on surfaces

    CERN Document Server

    Melnikov, Yuri A

    2017-01-01

    This book is comprehensive in its classical mathematical physics presentation, providing the reader with detailed instructions for obtaining Green's functions from scratch. Green's functions is an instrument easily accessible to practitioners who are engaged in design and exploitation of machines and structures in modern engineering practice. To date, there are no books available on the market that are devoted to the Green's function formalism for equations covered in this volume. The reader, with an undergraduate background in applied mathematics, can become an active user of the Green's function approach. For the first time, Green's functions are discussed for a specific class of problems dealing with potential fields induced in thin-wall structures and therefore, the reader will have first-hand access to a novel issue. This Work is accessible to researchers in applied mathematics, mechanics, and relevant disciplines such as engineering, as well as to upper level undergraduates and graduate students.

  11. Surface Potential of Polycrystalline Hematite in Aqueous Medium

    Directory of Open Access Journals (Sweden)

    Tajana Preočanin

    2011-01-01

    Full Text Available The surface potential of polycrystalline hematite in aqueous sodium perchlorate environment as a function of pH was examined. Surface potential of hematite was obtained from measured electrode potential of a nonporous polycrystalline hematite electrode. Acidic solution was titrated with base, and the backward titration with acid was performed. Substantial hysteresis was obtained which enabled location of the point of zero potential and equilibrium values of surface potentials. The theoretical interpretation of the equilibrium data was performed by applying the surface complexation model and the thermodynamic equilibrium constants for the first and the second step of surface protonation was obtained as logK1∘=11.3;logK2∘=2.8.

  12. Surface potential modeling and reconstruction in Kelvin probe force microscopy.

    Science.gov (United States)

    Xu, Jie; Wu, Yangqing; Li, Wei; Xu, Jun

    2017-09-08

    Kelvin probe force microscopy (KPFM) measurement has been extensively applied in metallic, semiconductor and organic electronic or photovoltaic devices, to characterize the local contact potential difference or surface potential of the samples at the nanoscale. Here, a comprehensive modeling of surface potential in KPFM is established, from the well-known single capacitance model to a precise electrodynamic model, considering the long range property of the electrostatic force in KPFM. The limitations and relations of different models are also discussed. Besides, the feedback condition of the KPFM system is reconsidered and modified, showing that the influence of the cantilever has been overestimated by about 20% in previous reports. Afterwards, the surface potential of charged Si-nanocrystals is reconstructed based on the electrodynamic model, and the calculated surface charge density is very consistent with the macroscopic capacitance-voltage (C-V) measurement. A deep understanding and correct reconstruction of surface potential is crucial to the quantitative analysis of KPFM results.

  13. Temperature increases on the external root surface during ...

    African Journals Online (AJOL)

    Aims: The aim of this study is to evaluate increases in temperature on the external root surface during endodontic treatment with different rotary systems. Materials and Methods: Fifty human mandibular incisors with a single root canal were selected. All root canals were instrumented using a size 20 Hedstrom file, and the ...

  14. Adsorption of lysozyme on base metal surfaces in the presence of an external electric potential.

    Science.gov (United States)

    Ei Ei, Htwe; Nakama, Yuhi; Tanaka, Hiroshi; Imanaka, Hiroyuki; Ishida, Naoyuki; Imamura, Koreyoshi

    2016-11-01

    The impact of external electric potential on the adsorption of a protein to base metal surfaces was examined. Hen egg white lysozyme (LSZ) and six types of base metal plates (stainless steel SUS316L (St), Ti, Ta, Zr, Cr, or Ni) were used as the protein and adsorption surface, respectively. LSZ was allowed to adsorb on the surface under different conditions (surface potential, pH, electrolyte type and concentration, surface material), which was monitored using an ellipsometer. LSZ adsorption was minimized in the potential range above a certain threshold and, in the surface potential range below the threshold, decreasing the surface potential increased the amount of protein adsorbed. The threshold potential for LSZ adsorption was shifted toward a positive value with increasing pH and was lower for Ta and Zr than for the others. A divalent anion salt (K2SO4) as an electrolyte exhibited the adsorption of LSZ in the positive potential range while a monovalent salt (KCl) did not. A comprehensive consideration of the obtained results suggests that two modes of interactions, namely the electric force by an external electric field and electrostatic interactions with ionized surface hydroxyl groups, act on the LSZ molecules and determine the extent of suppression of LSZ adsorption. All these findings appear to support the view that a base metal surface can be controlled for the affinity to a protein by manipulating the surface electric potential as has been reported on some electrode materials. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. The potentials of ICT application to increased relevance and ...

    African Journals Online (AJOL)

    The potentials of ICT application to increased relevance and sustainability of University Library Services in Nigeria. ... in Kenneth Dike library, University of Ibadan and University of Lagos Libraries and library search of recent literature on ICT application and marketing of ICT based services in Nigerian University libraries.

  16. Representing Global Reactive Potential Energy Surfaces Using Gaussian Processes.

    Science.gov (United States)

    Kolb, Brian; Marshall, Paul; Zhao, Bin; Jiang, Bin; Guo, Hua

    2017-04-06

    Representation of multidimensional global potential energy surfaces suitable for spectral and dynamical calculations from high-level ab initio calculations remains a challenge. Here, we present a detailed study on constructing potential energy surfaces using a machine learning method, namely, Gaussian process regression. Tests for the 3 A″ state of SH 2 , which facilitates the SH + H ↔ S( 3 P) + H 2 abstraction reaction and the SH + H' ↔ SH' + H exchange reaction, suggest that the Gaussian process is capable of providing a reasonable potential energy surface with a small number (∼1 × 10 2 ) of ab initio points, but it needs substantially more points (∼1 × 10 3 ) to converge reaction probabilities. The implications of these observations for construction of potential energy surfaces are discussed.

  17. Ab initio adiabatic and quasidiabatic potential energy surfaces of H ...

    Indian Academy of Sciences (India)

    s12039-015-1022-8. Ab initio adiabatic and quasidiabatic potential energy surfaces of H. ++. CN system. BHARGAVA ANUSURI and SANJAY KUMAR. ∗. Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India.

  18. Potential Increasing Dominance of Heterotrophy in the Global Ocean

    Science.gov (United States)

    Kvale, K.; Meissner, K. J.; Keller, D. P.

    2016-02-01

    Autotrophs are largely limited by resources in the modern ocean. However, standard metabolic theory suggests continued ocean warming could globally benefit heterotrophs, thereby reducing autotrophic nutrient limitation. The paleo record as well as modern observations offer evidence this has happened in the past and could happen again. Increasing dominance of heterotrophs would result in strong nutrient recycling in the upper ocean and high rates of net primary production (NPP), yet low carbon export to the deep ocean and sediments. We describe the transition towards such a state in the early 22nd century as a response to business-as-usual Representative Concentration Pathway forcing (RCP8.5) in an intermediate complexity Earth system model in three configurations: with and without an explicit calcifier phytoplankton class and calcite ballast model. In all models nutrient regeneration in the near surface becomes an increasingly important driver of primary production. The near-linear relationship between changes in NPP and global sea surface temperature (SST) found over the 21st century becomes exponential above a 2-4 °C global mean SST change. This transition to a more heterotrophic ocean agrees roughly with metabolic theory. Inclusion of small phytoplankton and calcifiers increase the model NPP:SST sensitivity because of their relatively higher nutrient affinity than general phytoplankton. Accounting for organic carbon "protected" from remineralization by carbonate ballast mitigates the exponential increase in NPP and provides an increasingly important pathway for deep carbon export with higher SST changes, despite simultaneous increasing carbonate dissolution rates due to ocean acidification.

  19. Surface motion and confinement potential for a microwave confined corona

    International Nuclear Information System (INIS)

    Ensley, D.L.

    1979-07-01

    Approximate time dependent solutions for surface velocities and potentials are given for a plane polarized microwave field confining a hot, over-dense plasma corona. Steady state solutions to Poissons' equation can be applied to the time dependent case, provided transit time effects are included. The product of ion pressure and potential wave (surface) velocity gives an average heating rate approx. 7/32 NKT 0 V/sub theta/ directly to the ions

  20. Improved DFT Potential Energy Surfaces via Improved Densities.

    Science.gov (United States)

    Kim, Min-Cheol; Park, Hansol; Son, Suyeon; Sim, Eunji; Burke, Kieron

    2015-10-01

    Density-corrected DFT is a method that cures several failures of self-consistent semilocal DFT calculations by using a more accurate density instead. A novel procedure employs the Hartree-Fock density to bonds that are more severely stretched than ever before. This substantially increases the range of accurate potential energy surfaces obtainable from semilocal DFT for many heteronuclear molecules. We show that this works for both neutral and charged molecules. We explain why and explore more difficult cases, for example, CH(+), where density-corrected DFT results are even better than sophisticated methods like CCSD. We give a simple criterion for when DC-DFT should be more accurate than self-consistent DFT that can be applied for most cases.

  1. Ab initio Potential Energy Surface for H-H2

    Science.gov (United States)

    Partridge, Harry; Bauschlicher, Charles W., Jr.; Stallcop, James R.; Levin, Eugene

    1993-01-01

    Ab initio calculations employing large basis sets are performed to determine an accurate potential energy surface for H-H2 interactions for a broad range of separation distances. At large distances, the spherically averaged potential determined from the calculated energies agrees well with the corresponding results determined from dispersion coefficients; the van der Waals well depth is predicted to be 75 +/- (mu)E(sub h). Large basis sets have also been applied to reexamine the accuracy of theoretical repulsive potential energy surfaces. Multipolar expansions of the computed H-H2 potential energy surface are reported for four internuclear separation distances (1.2, 1.401, 1.449, and 1.7a(sub 0) of the hydrogen molecule. The differential elastic scattering cross section calculated from the present results is compared with the measurements from a crossed beam experiment.

  2. Intermolecular potential energy surface for CS2 dimer.

    Science.gov (United States)

    Farrokhpour, Hossein; Mombeini, Zainab; Namazian, Mansoor; Coote, Michelle L

    2011-04-15

    A new four-dimensional intermolecular potential energy surface for CS(2) dimer is obtained by ab initio calculation of the interaction energies for a range of configurations and center-of-mass separation distances for the first time. The calculations were performed using the supermolecular approach at the Møller-Plesset second-order perturbation (MP2) level of theory with the augmented correlation consistent basis sets (aug-cc-pVxZ, x = D, T) and corrected for the basis-set superposition error using the full counterpoise correction method. A two-point extrapolation method was used to extrapolate the calculated energy points to the complete basis set limit. The effect of using the higher levels of theory, quadratic configuration interaction containing single, double, and perturbative triple excitations QCISD(T) and coupled cluster singles, doubles and perturbative triples excitations CCSD(T), on the shape of potential energy surface was investigated. It is shown that the MP2 level of theory apparently performs extremely poorly for describing the intermolecular potential energy surface, overestimating the total energy by a factor of nearly 1.73 in comparison with the QCISD(T) and CCSD(T) values. The value of isotropic dipole-dipole dispersion coefficient (C(6) ) of CS(2) fluid was obtained from the extrapolated MP2 potential energy surface. The MP2 extrapolated energy points were fitted to well-known analytical potential functions using two different methods to represent the potential energy surface analytically. The most stable configuration of the dimer was determined at R = 6.23 au, α = 90°, β = 90°, and γ = 90°, with a well depth of 3.980 kcal mol(-1) at the MP2 level of theory. Finally, the calculated second virial coefficients were compared with experimental values to test the quality of the presented potential energy surface. Copyright © 2010 Wiley Periodicals, Inc.

  3. The Contribution of Surface Potential to Diverse Problems in Electrostatics

    Science.gov (United States)

    Horenstein, M.

    2015-10-01

    Electrostatics spans many different subject areas. Some comprise “good electrostatics,” where charge is used for desirable purposes. Such areas include industrial manufacturing, electrophotography, surface modification, precipitators, aerosol control, and MEMS. Other areas comprise “bad electrostatics,” where charge is undesirable. Such areas include hazardous discharges, ESD, health effects, nuisance triboelectrification, particle contamination, and lightning. Conference proceedings such as this one inevitably include papers grouped around these topics. One common thread throughout is the surface potential developed when charge resides on an insulator surface. Often, the charged insulator will be in intimate contact with a ground plane. At other times, the charged insulator will be isolated. In either case, the resulting surface potential is important to such processes as propagating brush discharges, charge along a moving web, electrostatic biasing effects in MEMS, non-contacting voltmeters, field-effect transistor sensors, and the maximum possible charge on a woven fabric.

  4. Global Sequestration Potential of Increased Organic Carbon in Cropland Soils.

    Science.gov (United States)

    Zomer, Robert J; Bossio, Deborah A; Sommer, Rolf; Verchot, Louis V

    2017-11-14

    The role of soil organic carbon in global carbon cycles is receiving increasing attention both as a potentially large and uncertain source of CO 2 emissions in response to predicted global temperature rises, and as a natural sink for carbon able to reduce atmospheric CO 2 . There is general agreement that the technical potential for sequestration of carbon in soil is significant, and some consensus on the magnitude of that potential. Croplands worldwide could sequester between 0.90 and 1.85 Pg C/yr, i.e. 26-53% of the target of the "4p1000 Initiative: Soils for Food Security and Climate". The importance of intensively cultivated regions such as North America, Europe, India and intensively cultivated areas in Africa, such as Ethiopia, is highlighted. Soil carbon sequestration and the conservation of existing soil carbon stocks, given its multiple benefits including improved food production, is an important mitigation pathway to achieve the less than 2 °C global target of the Paris Climate Agreement.

  5. Increased nuclear thioredoxin-1 potentiates cadmium-induced cytotoxicity.

    Science.gov (United States)

    Go, Young-Mi; Orr, Michael; Jones, Dean P

    2013-01-01

    Cadmium (Cd) is a widely dispersed environmental agent that causes oxidative toxicity through mechanisms that are sensitive to thioredoxin-1 (Trx1). Trx1 is a cytoplasmic protein that translocates to nuclei during oxidative stress. Recent research shows that interaction of Trx1 with actin plays a critical role in cell survival and that increased nuclear Trx-1 potentiates proinflammatory signaling and death in cell and mouse models. These observations indicate that oxidative toxicity caused by low-dose Cd could involve disruption of actin-Trx1 interaction, nuclear Trx1 translocation, and potentiation of proinflammatory cell death mechanisms. In this study, we investigated the role of nuclei-localized Trx1 in Cd-induced inflammation and cytotoxicity using in vitro and in vivo models. The results show that Cd stimulated nuclear translocation of Trx1 and p65 of NF-κB. Elevation of Trx1 in nuclei in in vitro cells and kidney of transgenic mice potentiated Cd-stimulated NF-κB activation and cell death. Cd-stimulated Trx1 nuclear translocation and NF-κB activation were inhibited by cytochalasin D, an inhibitor of actin polymerization, suggesting that actin regulates Trx1 nuclear translocation and NF-κB activation by Cd. A nuclear-targeted dominant negative form of Trx1 blocked Cd-stimulated NF-κB activation and decreased cell death. Addition of zinc, known to antagonize Cd toxicity by increasing metallothionein, had no effect on Cd-stimulated nuclear translocation of Trx1 and NF-κB activation. Taken together, the results show that nuclear translocation and accumulation of redox-active Trx1 in nuclei play an important role in Cd-induced inflammation and cell death.

  6. Increasing shaft depth with rock hoisting to the surface. [USSR

    Energy Technology Data Exchange (ETDEWEB)

    Durov, E.M.

    1982-06-01

    Schemes of shaft construction with increasing shaft depth depend on: shaft depth, shaft diameter, types of hoisting systems, schemes of shaft reinforcement. Investigations carried out in underground coal mines in the USSR show that waste rock haulage to the surface by an independent hoisting system is most economical. Installation of this system depends on the existing hoisting scheme. When one of the operating cages or skips can be removed without a negative influence on mine operation the system of rock waste hoisting is used. The hoisting bucket used for rock removal from the shaft bottom moves in the shaft section from which one of the cages or skips has been removed. Examples of using this scheme in Donbass, Kuzbass and other coal basins are given. Economic aspects of waste material hoisting to the surface are analyzed. The system is economical when the remaining hoisting system can accept additional loads after removal of a cage or skip from the shaft. Investigations show that use of a bucket with a capacity from 2.5 to 3.0 m/sup 3/ for waste rock removal from the shaft being modernized and deepened is most economical.

  7. Surface potential domains on lamellar P3OT structures

    International Nuclear Information System (INIS)

    Perez-GarcIa, B; Abad, J; Urbina, A; Colchero, J; Palacios-Lidon, E

    2008-01-01

    In this work the electrostatic properties of poly(3-octylthiophene) thin films have been studied on a nanometer scale by means of electrostatic force microscopy and Kelvin probe microscopy (KPM). The KPM images reveal that different surface contact potential domains coexist on the polymer surface. This result, together with additional capacitance measurements, indicates that the potential domains are related to the existence of dipoles due to different molecular arrangements. Finally, capacitance measurements as a function of the tip-sample bias voltage show that in all regions large band bending effects take place

  8. Surface potential domains on lamellar P3OT structures

    Energy Technology Data Exchange (ETDEWEB)

    Perez-GarcIa, B [Departamento Fisica, Facultad de Quimica (Campus Espinardo), Universidad de Murcia, E-30100 Murcia (Spain); Abad, J [Departamento Fisica, Facultad de Quimica (Campus Espinardo), Universidad de Murcia, E-30100 Murcia (Spain); Urbina, A [Departamento Electronica, TecnologIa de Computadoras y Proyectos, Universidad Politecnica de Cartagena, E-30202 Cartagena (Spain); Colchero, J [Departamento Fisica, Facultad de Quimica (Campus Espinardo), Universidad de Murcia, E-30100 Murcia (Spain); Palacios-Lidon, E [Departamento Fisica, Facultad de Quimica (Campus Espinardo), Universidad de Murcia, E-30100 Murcia (Spain)

    2008-02-13

    In this work the electrostatic properties of poly(3-octylthiophene) thin films have been studied on a nanometer scale by means of electrostatic force microscopy and Kelvin probe microscopy (KPM). The KPM images reveal that different surface contact potential domains coexist on the polymer surface. This result, together with additional capacitance measurements, indicates that the potential domains are related to the existence of dipoles due to different molecular arrangements. Finally, capacitance measurements as a function of the tip-sample bias voltage show that in all regions large band bending effects take place.

  9. He-, Ne-, and Ar-phosgene intermolecular potential energy surfaces

    DEFF Research Database (Denmark)

    Munteanu, Cristian R.; Henriksen, Christian; Felker, Peter M.

    2013-01-01

    Using the CCSD(T) model, we evaluated the intermolecular potential energy surfaces of the He-, Ne-, and Ar-phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double......-phosgene surfaces were found to have absolute minima of -72.1, -140.4, and -326.6 cm -1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 Å, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants...

  10. An adaptive interpolation scheme for molecular potential energy surfaces

    Science.gov (United States)

    Kowalewski, Markus; Larsson, Elisabeth; Heryudono, Alfa

    2016-08-01

    The calculation of potential energy surfaces for quantum dynamics can be a time consuming task—especially when a high level of theory for the electronic structure calculation is required. We propose an adaptive interpolation algorithm based on polyharmonic splines combined with a partition of unity approach. The adaptive node refinement allows to greatly reduce the number of sample points by employing a local error estimate. The algorithm and its scaling behavior are evaluated for a model function in 2, 3, and 4 dimensions. The developed algorithm allows for a more rapid and reliable interpolation of a potential energy surface within a given accuracy compared to the non-adaptive version.

  11. Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials

    KAUST Repository

    Mutoro, Eva

    2012-01-05

    Perovskite oxides can exhibit a wide range of interesting characteristics such as being catalytically active and electronically/ionically conducting, and thus, they have been used in a number of solid-state devices such as solid oxide fuel cells (SOFCs) and sensors. As the surface compositions of perovskites can greatly influence the catalytic properties, knowing and controlling their surface compositions is crucial to enhance device performance. In this study, we demonstrate that the surface strontium (Sr) and cobalt (Co) concentrations of perovskite-based thin films can be controlled reversibly at elevated temperatures by applying small electrical potential biases. The surface compositional changes of La 0.8Sr 0.2CoO 3-δ (LSC 113), (La 0.5Sr 0.5) 2CoO 4±δ (LSC 214), and LSC 214-decorated LSC 113 films (LSC 113/214) were investigated in situ by utilizing synchrotron-based X-ray photoelectron spectroscopy (XPS), where the largest changes of surface Sr were found for the LSC 113/214 surface. These findings offer the potential of reversibly controlling the surface functionality of perovskites. © 2011 American Chemical Society.

  12. Effective medium potentials for molecule-surface interactions: H2 on Cu and Ni surfaces

    DEFF Research Database (Denmark)

    Nørskov, Jens Kehlet

    1989-01-01

    outside metal surfaces and the applicability is illustrated for H2 adsorbing on various Cu and Ni surfaces. Although very approximate, the calculated potentials seem to include a number of features observed experimentally: Ni is more active in dissociating H2 than Cu, and open surfaces are more active...... than close-packed ones. Moreover, the method is simple enough that one can contemplate studying variations in dissociation pathways over the surface unit cell. For the Cu surfaces these variations are substantial accounting for at least part of the variation of the sticking coefficient with the kinetic...

  13. Cardiac Body Surface Potentials in Rats with Experimental Pulmonary Hypertension during Ventricular Depolarization.

    Science.gov (United States)

    Suslonova, O V; Smirnova, S L; Roshchevskaya, I M

    2016-11-01

    The spatial and the amplitude-temporal parameters of cardiac body surface potentials were examined in female Wistar rats with experimental pulmonary hypertension during ventricular depolarization. The cardiac body surface potentials have been led from 64 subcutaneous electrodes evenly distributed across the chest surface prior to and 4 weeks after subcutaneous injection of a single dose of monocrotaline (60 mg/kg). Right ventricular hypertrophy and electrophysiological remodeling of the heart developed in rats with experimental pulmonary hypertension in 4 weeks after monocrotaline injection; these changes led to a significant increase in amplitude and temporal characteristics of the cardioelectric field on the body surface in comparison with the initial state.

  14. Ion-step method for surface potential sensing of silicon nanowires

    NARCIS (Netherlands)

    Chen, S.; van Nieuwkasteele, Jan William; van den Berg, Albert; Eijkel, Jan C.T.

    2016-01-01

    This paper presents a novel stimulus-response method for surface potential sensing of silicon nanowire (Si NW) field-effect transistors. When an "ion-step" from low to high ionic strength is given as a stimulus to the gate oxide surface, an increase of double layer capacitance is therefore expected.

  15. Surface potential of the water liquid-vapor interface

    Science.gov (United States)

    Wilson, Michael A.; Pohorille, Andrew; Pratt, Lawrence R.

    1988-01-01

    An analysis of an extended molecular dynamics calculation of the surface potential (SP) of the water liquid-vapor interface is presented. The SP predicted by the TIP4P model is -(130 + or - 50) mV. This value is of reasonable magnitude but of opposite sign to the expectations based on laboratory experiments. The electrostatic potential shows a nonmonotonic variation with depth into the liquid.

  16. Tuning the surface potential of Ag surfaces by chemisorption of oppositely-oriented thiolated carborane dipoles

    Czech Academy of Sciences Publication Activity Database

    Lübben, J.F.; Baše, Tomáš; Rupper, P.; Künniger, T.; Macháček, Jan; Guimond, S.

    2011-01-01

    Roč. 354, č. 1 (2011), s. 168-174 ISSN 0021-9797 R&D Projects: GA AV ČR(CZ) IAA400320901 Keywords : Adsorption * Thiolated carboranes * Silver surface * Surface potential * X-ray photoelectron spectroscopy Subject RIV: CA - Inorganic Chemistry Impact factor: 3.070, year: 2011

  17. Agronomic potential of some agricultural wastes as surface mulches ...

    African Journals Online (AJOL)

    Studies were carried out at the Teaching and Research Farm of the University of Cape Coast, in the minor seasons of 1992 and 1993, to assess the agronomic potential of some common agricultural wastes as surface mulches in terms of weed control, nematode population in soil, root-knot incidence and growth and yield of ...

  18. Potential Environmental Benefits from Increased Use of Bioenergy in China

    Science.gov (United States)

    Fan, Shuyang; Freedman, Bill; Gao, Jixi

    2007-09-01

    Because of its large population and rapidly growing economy, China is confronting a serious energy shortage and daunting environmental problems. An increased use of fuels derived from biomass could relieve some demand for nonrenewable sources of energy while providing environmental benefits in terms of cleaner air and reduced emissions of greenhouse gases. In 2003, China generated about 25.9 × 108 metric tons of industrial waste (liquid + solid), 14.7 × 108 metric tons/year (t/y) of manure (livestock + human), 7.1 × 108 t/y of crop residues and food-processing byproducts, 2 × 108 t/y of fuelwood and wood manufacturing residues, and 1.5 × 108 t/y of municipal waste. Biofuels derived from these materials could potentially displace the use of about 4.12 × 108 t/y of coal and 3.75 × 106 t/y of petroleum. An increased bioenergy use of this magnitude would help to reduce the emissions of key air pollutants: SO2 by 11.6 × 106 t/y, NOX by 1.48 × 106 t/y, CO2 by 1.07 × 109 t/y, and CH4 by 50 × 106 t/y. The reduced SO2 emissions would be equivalent to 54% of the national emissions in 2003, whereas those for CO2 are 30%. It is important to recognize, however, that large increases in the use of biomass fuels also could result in socioeconomic and environmental problems such as less production of food and damage caused to natural habitats.

  19. Can atom-surface potential measurements test atomic structure models?

    Science.gov (United States)

    Lonij, Vincent P A; Klauss, Catherine E; Holmgren, William F; Cronin, Alexander D

    2011-06-30

    van der Waals (vdW) atom-surface potentials can be excellent benchmarks for atomic structure calculations. This is especially true if measurements are made with two different types of atoms interacting with the same surface sample. Here we show theoretically how ratios of vdW potential strengths (e.g., C₃(K)/C₃(Na)) depend sensitively on the properties of each atom, yet these ratios are relatively insensitive to properties of the surface. We discuss how C₃ ratios depend on atomic core electrons by using a two-oscillator model to represent the contribution from atomic valence electrons and core electrons separately. We explain why certain pairs of atoms are preferable to study for future experimental tests of atomic structure calculations. A well chosen pair of atoms (e.g., K and Na) will have a C₃ ratio that is insensitive to the permittivity of the surface, whereas a poorly chosen pair (e.g., K and He) will have a ratio of C₃ values that depends more strongly on the permittivity of the surface.

  20. Oxidative shift in tissue redox potential increases beat-to-beat variability of action potential duration.

    Science.gov (United States)

    Kistamás, Kornél; Hegyi, Bence; Váczi, Krisztina; Horváth, Balázs; Bányász, Tamás; Magyar, János; Szentandrássy, Norbert; Nánási, Péter P

    2015-07-01

    Profound changes in tissue redox potential occur in the heart under conditions of oxidative stress frequently associated with cardiac arrhythmias. Since beat-to-beat variability (short term variability, SV) of action potential duration (APD) is a good indicator of arrhythmia incidence, the aim of this work was to study the influence of redox changes on SV in isolated canine ventricular cardiomyocytes using a conventional microelectrode technique. The redox potential was shifted toward a reduced state using a reductive cocktail (containing dithiothreitol, glutathione, and ascorbic acid) while oxidative changes were initiated by superfusion with H2O2. Redox effects were evaluated as changes in "relative SV" determined by comparing SV changes with the concomitant APD changes. Exposure of myocytes to the reductive cocktail decreased SV significantly without any detectable effect on APD. Application of H2O2 increased both SV and APD, but the enhancement of SV was the greater, so relative SV increased. Longer exposure to H2O2 resulted in the development of early afterdepolarizations accompanied by tremendously increased SV. Pretreatment with the reductive cocktail prevented both elevation in relative SV and the development of afterdepolarizations. The results suggest that the increased beat-to-beat variability during an oxidative stress contributes to the generation of cardiac arrhythmias.

  1. Three-dimensional potential energy surface of Ar–CO

    Energy Technology Data Exchange (ETDEWEB)

    Sumiyoshi, Yoshihiro, E-mail: y-sumiyoshi@gunma-u.ac.jp [Division of Pure and Applied Science, Graduate School of Science and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma 371-8510 (Japan); Endo, Yasuki [Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902 (Japan)

    2015-01-14

    A three-dimensional intermolecular potential energy surface of the Ar–CO complex has been determined by fitting most of the previously reported spectroscopic data, where observed transition frequencies by microwave, millimeter-wave, submillimeter-wave, and infrared spectroscopy were reproduced simultaneously within their experimental accuracies. A free rotor model Hamiltonian considering all the freedom of motions for an atom-diatom system was applied to calculate vibration-rotation energies. A three-dimensional potential energy surface obtained by ab initio calculations at the CCSD(T)-F12b/aug-cc-pV5Z level of theory was parameterized by a model function consisting of 46 parameters. They were used as initial values for the least-squares analysis of the experimental data. A total of 20 parameters were optimized to reproduce all the spectroscopic data.

  2. Effect of remote sea surface temperature change on tropical cyclone potential intensity.

    Science.gov (United States)

    Vecchi, Gabriel A; Soden, Brian J

    2007-12-13

    The response of tropical cyclone activity to global warming is widely debated. It is often assumed that warmer sea surface temperatures provide a more favourable environment for the development and intensification of tropical cyclones, but cyclone genesis and intensity are also affected by the vertical thermodynamic properties of the atmosphere. Here we use climate models and observational reconstructions to explore the relationship between changes in sea surface temperature and tropical cyclone 'potential intensity'--a measure that provides an upper bound on cyclone intensity and can also reflect the likelihood of cyclone development. We find that changes in local sea surface temperature are inadequate for characterizing even the sign of changes in potential intensity, but that long-term changes in potential intensity are closely related to the regional structure of warming; regions that warm more than the tropical average are characterized by increased potential intensity, and vice versa. We use this relationship to reconstruct changes in potential intensity over the twentieth century from observational reconstructions of sea surface temperature. We find that, even though tropical Atlantic sea surface temperatures are currently at a historical high, Atlantic potential intensity probably peaked in the 1930s and 1950s, and recent values are near the historical average. Our results indicate that--per unit local sea surface temperature change--the response of tropical cyclone activity to natural climate variations, which tend to involve localized changes in sea surface temperature, may be larger than the response to the more uniform patterns of greenhouse-gas-induced warming.

  3. Electronic structure, molecular bonding and potential energy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ruedenberg, K. [Ames Laboratory, IA (United States)

    1993-12-01

    By virtue of the universal validity of the generalized Born-Oppenheimer separation, potential energy surfaces (PES`) represent the central conceptual as well as quantitative entities of chemical physics and provide the basis for the understanding of most physicochemical phenomena in many diverse fields. The research in this group deals with the elucidation of general properties of PES` as well as with the quantitative determination of PES` for concrete systems, in particular pertaining to reactions involving carbon, oxygen, nitrogen and hydrogen molecules.

  4. Surface deformation during an action potential in pearled cells

    Science.gov (United States)

    Mussel, Matan; Fillafer, Christian; Ben-Porath, Gal; Schneider, Matthias F.

    2017-11-01

    Electric pulses in biological cells (action potentials) have been reported to be accompanied by a propagating cell-surface deformation with a nanoscale amplitude. Typically, this cell surface is covered by external layers of polymer material (extracellular matrix, cell wall material, etc.). It was recently demonstrated in excitable plant cells (Chara braunii) that the rigid external layer (cell wall) hinders the underlying deformation. When the cell membrane was separated from the cell wall by osmosis, a mechanical deformation, in the micrometer range, was observed upon excitation of the cell. The underlying mechanism of this mechanical pulse has, to date, remained elusive. Herein we report that Chara cells can undergo a pearling instability, and when the pearled fragments were excited even larger and more regular cell shape changes were observed (˜10 -100 μ m in amplitude). These transient cellular deformations were captured by a curvature model that is based on three parameters: surface tension, bending rigidity, and pressure difference across the surface. In this paper these parameters are extracted by curve-fitting to the experimental cellular shapes at rest and during excitation. This is a necessary step to identify the mechanical parameters that change during an action potential.

  5. Theoretical studies of potential energy surfaces and computational methods

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, R. [Argonne National Laboratory, IL (United States)

    1993-12-01

    This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. This difficult challenge is met with general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions, are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.

  6. Toward a Molecular Understanding of Protein Solubility: Increased Negative Surface Charge Correlates with Increased Solubility

    Science.gov (United States)

    Kramer, Ryan M.; Shende, Varad R.; Motl, Nicole; Pace, C. Nick; Scholtz, J. Martin

    2012-01-01

    Protein solubility is a problem for many protein chemists, including structural biologists and developers of protein pharmaceuticals. Knowledge about how intrinsic factors influence solubility is limited due to the difficulty of obtaining quantitative solubility measurements. Solubility measurements in buffer alone are difficult to reproduce, because gels or supersaturated solutions often form, making it impossible to determine solubility values for many proteins. Protein precipitants can be used to obtain comparative solubility measurements and, in some cases, estimations of solubility in buffer alone. Protein precipitants fall into three broad classes: salts, long-chain polymers, and organic solvents. Here, we compare the use of representatives from two classes of precipitants, ammonium sulfate and polyethylene glycol 8000, by measuring the solubility of seven proteins. We find that increased negative surface charge correlates strongly with increased protein solubility and may be due to strong binding of water by the acidic amino acids. We also find that the solubility results obtained for the two different precipitants agree closely with each other, suggesting that the two precipitants probe similar properties that are relevant to solubility in buffer alone. PMID:22768947

  7. High volume hydraulic fracturing operations: potential impacts on surface water and human health.

    Science.gov (United States)

    Mrdjen, Igor; Lee, Jiyoung

    2016-08-01

    High volume, hydraulic fracturing (HVHF) processes, used to extract natural gas and oil from underground shale deposits, pose many potential hazards to the environment and human health. HVHF can negatively affect the environment by contaminating soil, water, and air matrices with potential pollutants. Due to the relatively novel nature of the process, hazards to surface waters and human health are not well known. The purpose of this article is to link the impacts of HVHF operations on surface water integrity, with human health consequences. Surface water contamination risks include: increased structural failure rates of unconventional wells, issues with wastewater treatment, and accidental discharge of contaminated fluids. Human health risks associated with exposure to surface water contaminated with HVHF chemicals include increased cancer risk and turbidity of water, leading to increased pathogen survival time. Future research should focus on modeling contamination spread throughout the environment, and minimizing occupational exposure to harmful chemicals.

  8. Potential energy surface for ? dissociation including spin-orbit effects

    Science.gov (United States)

    Siebert, Matthew R.; Aquino, Adelia J. A.; de Jong, Wibe A.; Granucci, Giovanni; Hase, William L.

    2012-10-01

    Previous experiments [J. Phys. Chem. A 116, 2833 (2012)] have studied the dissociation of 1,2-diiodoethane radical cation ( ? ) and found a one-dimensional distribution of translational energy, an odd finding considering most product relative translational energy distributions are two-dimensional. The goal of this study is to obtain an accurate understanding of the potential energy surface (PES) topology for the unimolecular decomposition reaction ? → C2H4I+ + I•. This is done through comparison of many single-reference electronic structure methods, coupled-cluster single-point (energy) calculations, and multi-reference energy calculations used to quantify spin-orbit (SO) coupling effects. We find that the structure of the ? reactant has a substantial effect on the role of the SO coupling on the reaction energy. Both the BHandH and MP2 theories with an ECP/6-31++G** basis set, and without SO coupling corrections, provide accurate models for the reaction energetics. MP2 theory gives an unsymmetric structure with different C-I bond lengths, resulting in a SO energy for ? similar to that for the product I-atom and a negligible SO correction to the reaction energy. In contrast, DFT gives a symmetric structure for ? , similar to that of the neutral C2H4I2 parent, resulting in a substantial SO correction and increasing the reaction energy by 6.0-6.5 kcalmol-1. Also, we find that, for this system, coupled-cluster single-point energy calculations are inaccurate, since a small change in geometry can lead to a large change in energy.

  9. Effects of shrub and tree cover increase on the near-surface atmosphere in northern Fennoscandia

    Science.gov (United States)

    Rydsaa, Johanne H.; Stordal, Frode; Bryn, Anders; Tallaksen, Lena M.

    2017-09-01

    Increased shrub and tree cover in high latitudes is a widely observed response to climate change that can lead to positive feedbacks to the regional climate. In this study we evaluate the sensitivity of the near-surface atmosphere to a potential increase in shrub and tree cover in the northern Fennoscandia region. We have applied the Weather Research and Forecasting (WRF) model with the Noah-UA land surface module in evaluating biophysical effects of increased shrub cover on the near-surface atmosphere at a fine resolution (5.4 km × 5.4 km). Perturbation experiments are performed in which we prescribe a gradual increase in taller vegetation in the alpine shrub and tree cover according to empirically established bioclimatic zones within the study region. We focus on the spring and summer atmospheric response. To evaluate the sensitivity of the atmospheric response to inter-annual variability in climate, simulations were conducted for two contrasting years, one warm and one cold. We find that shrub and tree cover increase leads to a general increase in near-surface temperatures, with the highest influence seen during the snowmelt season and a more moderate effect during summer. We find that the warming effect is stronger in taller vegetation types, with more complex canopies leading to decreases in the surface albedo. Counteracting effects include increased evapotranspiration, which can lead to increased cloud cover, precipitation, and snow cover. We find that the strength of the atmospheric feedback is sensitive to snow cover variations and to a lesser extent to summer temperatures. Our results show that the positive feedback to high-latitude warming induced by increased shrub and tree cover is a robust feature across inter-annual differences in meteorological conditions and will likely play an important role in land-atmosphere feedback processes in the future.

  10. Nuclear momentum distribution and potential energy surface in hexagonal ice

    Science.gov (United States)

    Lin, Lin; Morrone, Joseph; Car, Roberto; Parrinello, Michele

    2011-03-01

    The proton momentum distribution in ice Ih has been recently measured by deep inelastic neutron scattering and calculated from open path integral Car-Parrinello simulation. Here we report a detailed investigation of the relation between momentum distribution and potential energy surface based on both experiment and simulation results. The potential experienced by the proton is largely harmonic and characterized by 3 principal frequencies, which can be associated to weighted averages of phonon frequencies via lattice dynamics calculations. This approach also allows us to examine the importance of quantum effects on the dynamics of the oxygen nuclei close to the melting temperature. Finally we quantify the anharmonicity that is present in the potential acting on the protons. This work is supported by NSF and by DOE.

  11. In vivo Raman spectroscopy detects increased epidermal antioxidative potential with topically applied carotenoids

    International Nuclear Information System (INIS)

    Lademann, J; Richter, H; Patzelt, A; Darvin, M; Sterry, W; Fluhr, J W; Caspers, P J; Van der Pol, A; Zastrow, L

    2009-01-01

    In the present study, the distribution of the carotenoids as a marker for the complete antioxidative potential in human skin was investigated before and after the topical application of carotenoids by in vivo Raman spectroscopy with an excitation wavelength of 785 nm. The carotenoid profile was assessed after a short term topical application in 4 healthy volunteers. In the untreated skin, the highest concentration of natural carotenoids was detected in different layers of the stratum corneum (SC) close to the skin surface. After topical application of carotenoids, an increase in the antioxidative potential in the skin could be observed. Topically applied carotenoids penetrate deep into the epidermis down to approximately 24 μm. This study supports the hypothesis that antioxidative substances are secreted via eccrine sweat glands and/or sebaceous glands to the skin surface. Subsequently they penetrate into the different layers of the SC

  12. Biomass production and potential water stress increase with ...

    African Journals Online (AJOL)

    The choice of planting density and tree genotype are basic decisions when establishing a forest stand. Understanding the interaction between planting density and genotype, and their relationship with biomass production and potential water stress, is crucial as forest managers are faced with a changing climate. However ...

  13. Measuring surface flow velocity with smartphones: potential for citizen observatories

    Science.gov (United States)

    Weijs, Steven V.; Chen, Zichong; Brauchli, Tristan; Huwald, Hendrik

    2014-05-01

    Stream flow velocity is an important variable for discharge estimation and research on sediment dynamics. Given the influence of the latter on rating curves (stage-discharge relations), and the relative scarcity of direct streamflow measurements, surface velocity measurements can offer important information for, e.g., flood warning, hydropower, and hydrological science and engineering in general. With the growing amount of sensing and computing power in the hands of more outdoorsy individuals, and the advances in image processing techniques, there is now a tremendous potential to obtain hydrologically relevant data from motivated citizens. This is the main focus of the interdisciplinary "WeSenseIt" project, a citizen observatory of water. In this subproject, we investigate the feasibility of stream flow surface velocity measurements from movie clips taken by (smartphone-) cameras. First results from movie-clip derived velocity information will be shown and compared to reference measurements.

  14. Quantitative parameterization of soil surface structure with increasing rainfall volumes

    OpenAIRE

    Edison Aparecido Mome Filho

    2016-01-01

    The study of soil structure allows inferences on soil behavior. Quantitative parameters are oftentimes required to describe soil structure and the multifractal ones are still underused in soil science. Some studies have shown relations between the multifractal spectrum and both soil surface roughness decay by rainfall and porous system heterogeneity, however, a particular multifractal response to a specific soil behavior is not established yet. Therefore, the objectives of this research were:...

  15. Pseudospectral Gaussian quantum dynamics: Efficient sampling of potential energy surfaces.

    Science.gov (United States)

    Heaps, Charles W; Mazziotti, David A

    2016-04-28

    Trajectory-based Gaussian basis sets have been tremendously successful in describing high-dimensional quantum molecular dynamics. In this paper, we introduce a pseudospectral Gaussian-based method that achieves accurate quantum dynamics using efficient, real-space sampling of the time-dependent basis set. As in other Gaussian basis methods, we begin with a basis set expansion using time-dependent Gaussian basis functions guided by classical mechanics. Unlike other Gaussian methods but characteristic of the pseudospectral and collocation methods, the basis set is tested with N Dirac delta functions, where N is the number of basis functions, rather than using the basis function as test functions. As a result, the integration for matrix elements is reduced to function evaluation. Pseudospectral Gaussian dynamics only requires O(N) potential energy calculations, in contrast to O(N(2)) evaluations in a variational calculation. The classical trajectories allow small basis sets to sample high-dimensional potentials. Applications are made to diatomic oscillations in a Morse potential and a generalized version of the Henon-Heiles potential in two, four, and six dimensions. Comparisons are drawn to full analytical evaluation of potential energy integrals (variational) and the bra-ket averaged Taylor (BAT) expansion, an O(N) approximation used in Gaussian-based dynamics. In all cases, the pseudospectral Gaussian method is competitive with full variational calculations that require a global, analytical, and integrable potential energy surface. Additionally, the BAT breaks down when quantum mechanical coherence is particularly strong (i.e., barrier reflection in the Morse oscillator). The ability to obtain variational accuracy using only the potential energy at discrete points makes the pseudospectral Gaussian method a promising avenue for on-the-fly dynamics, where electronic structure calculations become computationally significant.

  16. Bacteria increase arid-land soil surface temperature through the production of sunscreens.

    Science.gov (United States)

    Couradeau, Estelle; Karaoz, Ulas; Lim, Hsiao Chien; Nunes da Rocha, Ulisses; Northen, Trent; Brodie, Eoin; Garcia-Pichel, Ferran

    2016-01-20

    Soil surface temperature, an important driver of terrestrial biogeochemical processes, depends strongly on soil albedo, which can be significantly modified by factors such as plant cover. In sparsely vegetated lands, the soil surface can be colonized by photosynthetic microbes that build biocrust communities. Here we use concurrent physical, biochemical and microbiological analyses to show that mature biocrusts can increase surface soil temperature by as much as 10 °C through the accumulation of large quantities of a secondary metabolite, the microbial sunscreen scytonemin, produced by a group of late-successional cyanobacteria. Scytonemin accumulation decreases soil albedo significantly. Such localized warming has apparent and immediate consequences for the soil microbiome, inducing the replacement of thermosensitive bacterial species with more thermotolerant forms. These results reveal that not only vegetation but also microorganisms are a factor in modifying terrestrial albedo, potentially impacting biosphere feedbacks on past and future climate, and call for a direct assessment of such effects at larger scales.

  17. Changes of Surface Electric Potential of Bones Depending on Their Age

    OpenAIRE

    Freimanis, E; Dehtjars, J; Vendiņa, V

    2014-01-01

    The aim of this research was to determine how surface electric potential of bones changes with their age and how it correlates with mechanical properties of bones. Surface electric potential was measured in 6 cross-sectional zones of the tibia. Changes of bones surface electric potential with age were determined and correlations between surface electric potential and mechanical properties were derived.

  18. An Ab Initio Based Potential Energy Surface for Water

    Science.gov (United States)

    Partridge, Harry; Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)

    1996-01-01

    We report a new determination of the water potential energy surface. A high quality ab initio potential energy surface (PES) and dipole moment function of water have been computed. This PES is empirically adjusted to improve the agreement between the computed line positions and those from the HITRAN 92 data base. The adjustment is small, nonetheless including an estimate of core (oxygen 1s) electron correlation greatly improves the agreement with experiment. Of the 27,245 assigned transitions in the HITRAN 92 data base for H2(O-16), the overall root mean square (rms) deviation between the computed and observed line positions is 0.125/cm. However the deviations do not correspond to a normal distribution: 69% of the lines have errors less than 0.05/cm. Overall, the agreement between the line intensities computed in the present work and those contained in the data base is quite good, however there are a significant number of line strengths which differ greatly.

  19. Forces on nuclei moving on autoionizing molecular potential energy surfaces.

    Science.gov (United States)

    Moiseyev, Nimrod

    2017-01-14

    Autoionization of molecular systems occurs in diatomic molecules and in small biochemical systems. Quantum chemistry packages enable calculation of complex potential energy surfaces (CPESs). The imaginary part of the CPES is associated with the autoionization decay rate, which is a function of the molecular structure. Molecular dynamics simulations, within the framework of the Born-Oppenheimer approximation, require the definition of a force field. The ability to calculate the forces on the nuclei in bio-systems when autoionization takes place seems to rely on an understanding of radiative damages in RNA and DNA arising from the release of slow moving electrons which have long de Broglie wavelengths. This work addresses calculation of the real forces on the nuclei moving on the CPES. By using the transformation of the time-dependent Schrödinger equation, previously used by Madelung, we proved that the classical forces on nuclei moving on the CPES correlated with the gradient of the real part of the CPES. It was proved that the force on the nuclei of the metastable molecules is time independent although the probability to detect metastable molecules exponentially decays. The classical force is obtained from the transformed Schrödinger equation when ℏ=0 and the Schrödinger equation is reduced to the classical (Newtonian) equations of motion. The forces on the nuclei regardless on what potential energy surface they move (parent CPES or product real PESs) vary in time due to the autoionization process.

  20. Residual compressive surface stress increases the bending strength of dental zirconia.

    Science.gov (United States)

    Inokoshi, Masanao; Zhang, Fei; Vanmeensel, Kim; De Munck, Jan; Minakuchi, Shunsuke; Naert, Ignace; Vleugels, Jozef; Van Meerbeek, Bart

    2017-04-01

    To assess the influence of surface treatment and thermal annealing on the four-point bending strength of two ground dental zirconia grades. Fully-sintered zirconia specimens (4.0×3.0×45.0mm 3 ) of Y-TZP zirconia (LAVA Plus, 3M ESPE) and Y-TZP/Al 2 O 3 zirconia (ZirTough, Kuraray Noritake) were subjected to four surface treatments: (1) 'GROUND': all surfaces were ground with a diamond-coated grinding wheel on a grinding machine; (2) 'GROUND+HEAT': (1) followed by annealing at 1100°C for 30min; (3) 'GROUND+Al 2 O 3 SANDBLASTED': (1) followed by sandblasting using Al 2 O 3 ; (4) 'GROUND+CoJet SANDBLASTED': (1) followed by tribochemical silica (CoJet) sandblasting. Micro-Raman spectroscopy was used to assess the zirconia-phase composition and potentially induced residual stress. The four-point bending strength was measured using a universal material-testing machine. Weibull analysis revealed a substantially higher Weibull modulus and slightly higher characteristic strength for ZirTough (Kuraray Noritake) than for LAVA Plus (3M ESPE). For both zirconia grades, the 'GROUND' zirconia had the lowest Weibull modulus in combination with a high characteristic strength. Sandblasting hardly changed the bending strength but substantially increased the Weibull modulus of the ground zirconia, whereas a thermal treatment increased the Weibull modulus of both zirconia grades but resulted in a significantly lower bending strength. Micro-Raman analysis revealed a higher residual compressive surface stress that correlated with an increased bending strength. Residual compressive surface stress increased the bending strength of dental zirconia. Thermal annealing substantially reduced the bending strength but increased the consistency (reliability) of 'GROUND' zirconia. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. Plasma of Argon Increases Cell Attachment and Bacterial Decontamination on Different Implant Surfaces.

    Science.gov (United States)

    Canullo, Luigi; Genova, Tullio; Wang, Hom-Lay; Carossa, Stefano; Mussano, Federico

    This in vitro study tested the effects of argon atmospheric pressure dielectric barrier discharge (APDBD) on different implant surfaces with regard to physical changes, bacterial decontamination, and osteoblast adhesion. Seven hundred twenty disks with three different surface topographies-machined (MAC), titanium plasma-sprayed (TPS), and zirconia-blasted and acid-etched (ZRT)-were tested in this experiment. Bacterial adhesion tests were performed repeatedly on a simplified biofilm of Streptococcus mitis. Bacteria were incubated in the presence of the samples, which were subsequently either left untreated as controls or treated with APDBD for 30, 60, and 120 seconds. Samples were then metalized, prior to the recurring acquisition of images using a scanning electronic microscope (SEM). Protein adsorption, surface wettability, and early biologic response were determined for both treated (120 seconds) and untreated implant surfaces. For depicting the eukaryotic cell behavior, preosteoblastic murine cells were used. Cells were conveniently stained, and nuclei were counted. Cell viability was assessed by a chemiluminescent assay at 1, 2, and 3 days. On all treated samples, values of the contact angle measurements were lower than 10 degrees. The untreated samples showed values of contact angle of 80, 100, and 110 degrees, respectively, for MAC, TPS, and ZRT. The protein adsorption on TPS and ZRT was significantly increased after the plasma of argon treatment. However, no significant effect was noted on the MAC disks. The number and the cell spreading area of adherent osteoblasts significantly increased in all treated surfaces. Nonetheless, argon treatment did not influence the osteoblast proliferation and viability at different time points. Bacteria adhesion was significantly reduced, even after 60 seconds of argon treatment. Preliminary data showed that argon atmospheric pressure dielectric barrier discharge disinfected the implant surface, with potential to promote

  2. Surface-wave potential for triggering tectonic (nonvolcanic) tremor

    Science.gov (United States)

    Hill, D.P.

    2010-01-01

    Source processes commonly posed to explain instances of remote dynamic triggering of tectonic (nonvolcanic) tremor by surface waves include frictional failure and various modes of fluid activation. The relative potential for Love- and Rayleigh-wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike-slip faults under the Coulomb-Griffith failure criteria as a function of incidence angle is anticorrelated over the 15- to 30-km-depth range that hosts tectonic tremor. Love-wave potential is high for strike-parallel incidence on low-angle reverse faults and null for strike-normal incidence; the opposite holds for Rayleigh waves. Love-wave potential is high for both strike-parallel and strike-normal incidence on vertical, strike-slip faults and minimal for ~45?? incidence angles. The opposite holds for Rayleigh waves. This pattern is consistent with documented instances of tremor triggered by Love waves incident on the Cascadia mega-thrust and the San Andreas fault (SAF) in central California resulting from shear failure on weak faults (apparent friction, ????? 0.2). However, documented instances of tremor triggered by surface waves with strike-parallel incidence along the Nankai megathrust beneath Shikoku, Japan, is associated primarily with Rayleigh waves. This is consistent with the tremor bursts resulting from mixed-mode failure (crack opening and shear failure) facilitated by near-lithostatic ambient pore pressure, low differential stress, with a moderate friction coefficient (?? ~ 0.6) on the Nankai subduction interface. Rayleigh-wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process, except perhaps for an indirect role on the SAF in sustaining tremor into the Rayleigh-wave coda that was initially triggered by Love waves.

  3. Potential Energy Cost Savings from Increased Commercial Energy Code Compliance

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Michael I.; Hart, Philip R.; Athalye, Rahul A.; Zhang, Jian; Cohan, David F.

    2016-08-22

    An important question for commercial energy code compliance is: “How much energy cost savings can better compliance achieve?” This question is in sharp contrast to prior efforts that used a checklist of code requirements, each of which was graded pass or fail. Percent compliance for any given building was simply the percent of individual requirements that passed. A field investigation method is being developed that goes beyond the binary approach to determine how much energy cost savings is not realized. Prototype building simulations were used to estimate the energy cost impact of varying levels of non-compliance for newly constructed office buildings in climate zone 4C. Field data collected from actual buildings on specific conditions relative to code requirements was then applied to the simulation results to find the potential lost energy savings for a single building or for a sample of buildings. This new methodology was tested on nine office buildings in climate zone 4C. The amount of additional energy cost savings they could have achieved had they complied fully with the 2012 International Energy Conservation Code is determined. This paper will present the results of the test, lessons learned, describe follow-on research that is needed to verify that the methodology is both accurate and practical, and discuss the benefits that might accrue if the method were widely adopted.

  4. Predicting Recovery Potential for Individual Stroke Patients Increases Rehabilitation Efficiency.

    Science.gov (United States)

    Stinear, Cathy M; Byblow, Winston D; Ackerley, Suzanne J; Barber, P Alan; Smith, Marie-Claire

    2017-04-01

    Several clinical measures and biomarkers are associated with motor recovery after stroke, but none are used to guide rehabilitation for individual patients. The objective of this study was to evaluate the implementation of upper limb predictions in stroke rehabilitation, by combining clinical measures and biomarkers using the Predict Recovery Potential (PREP) algorithm. Predictions were provided for patients in the implementation group (n=110) and withheld from the comparison group (n=82). Predictions guided rehabilitation therapy focus for patients in the implementation group. The effects of predictive information on clinical practice (length of stay, therapist confidence, therapy content, and dose) were evaluated. Clinical outcomes (upper limb function, impairment and use, independence, and quality of life) were measured 3 and 6 months poststroke. The primary clinical practice outcome was inpatient length of stay. The primary clinical outcome was Action Research Arm Test score 3 months poststroke. Length of stay was 1 week shorter for the implementation group (11 days; 95% confidence interval, 9-13 days) than the comparison group (17 days; 95% confidence interval, 14-21 days; P =0.001), controlling for upper limb impairment, age, sex, and comorbidities. Therapists were more confident ( P =0.004) and modified therapy content according to predictions for the implementation group ( P rehabilitation efficiency after stroke without compromising clinical outcome. URL: http://anzctr.org.au. Unique identifier: ACTRN12611000755932. © 2017 American Heart Association, Inc.

  5. Clastogenic Factors as Potential Biomarkers of Increased Superoxide Production

    Directory of Open Access Journals (Sweden)

    Ingrid Emerit

    2007-01-01

    Full Text Available The formation of clastogenic factors (CF and their damaging effects are mediated by superoxide, since superoxide dismutase is regularly protective. CF are produced via superoxide and stimulate the production of superoxide by monocytes and neutrophils. This results in a selfsustaining and longlasting process of clastogenesis, which may exceed the DNA repair system and ultimately lead to cancer (Emerit, 1994. An increased cancer risk is indeed observed in conditions accompanied by CF formation. These include irradiated persons, patients with chronic inflammatory diseases, HIV-infected persons and the chromosomal breakage syndromes ataxia telangiectasia, Bloom’s syndrome and Fanconi’s anemia. Biochemical analysis has identifi ed lipid peroxidation products, arachidonic acid metabolites, nucleotides of inosine and cytokines, in particular tumor necrosis factor alpha, as the clastogenic and also superoxide stimulating components of CF. Due to their chromosome damaging effects, these oxidants can be detected with classical cytogenetic techniques. Their synergistic action renders the CF-test particularly sensitive for the detection of a pro-oxidant state. Correlations were observed between CF and other biomarkers of oxidative stress such as decreases in total plasma thiols or increases in TBARS or chemiluminescence. Correlations between CF and disease activity, between CF and radiation exposure, suggest the study of CF for monitoring these conditions. CF may also be useful as biochemical markers and intermediate endpoints for the evaluation of promising antioxidant drugs. CF formation represents a link between chronic inflammation and carcinogenesis. Prophylactic use of superoxide scavengers as anticarcinogens is therefore suggested.

  6. CO dimer: new potential energy surface and rovibrational calculations.

    Science.gov (United States)

    Dawes, Richard; Wang, Xiao-Gang; Carrington, Tucker

    2013-08-15

    The spectrum of CO dimer was investigated by solving the rovibrational Schrödinger equation on a new potential energy surface constructed from coupled-cluster ab initio points. The Schrödinger equation was solved with a Lanczos algorithm. Several 4D (rigid monomer) global ab initio potential energy surfaces (PESs) were made using a previously reported interpolating moving least-squares (IMLS) fitting procedure specialized to describe the interaction of two linear fragments. The potential has two nonpolar minima giving rise to a complicated set of energy level stacks, which are very sensitive to the shapes and relative depths of the two wells. Although the CO dimer has defied previous attempts at an accurate purely ab initio description our best surface yields results in good agreement with experiment. Root-mean-square (rms) fitting errors of less than 0.1 cm(-1) were obtained for each of the fits using 2226 ab initio data at different levels. This allowed direct assessment of the quality of various levels of ab initio theory for prediction of spectra. Our tests indicate that standard CCSD(T) is slow to converge the interaction energy even when sextuple zeta bases as large as ACV6Z are used. The explicitly correlated CCSD(T)-F12b method was found to recover significantly more correlation energy (from singles and doubles) at the CBS limit. Correlation of the core-electrons was found to be important for this system. The best PES was obtained by extrapolation of calculations at the CCSD(T)(AE)-F12b/CVnZ-F12 (n = 3,4) levels. The calculated energy levels were compared to 105 J ≤ 10 levels from experiment. The rms error for 68 levels with J ≤ 6 is only 0.29 cm(-1). The calculated energy levels were assigned stack labels using several tools. New stacks were found. One of them, stack y1, has an energy lower than many previously known stacks and may be observable.

  7. Technology of wear resistance increase of surface elements of friction couples using solid lubricants

    Science.gov (United States)

    Morgunov, A. P.; Masyagin, V. B.; Derkach, V. V.; Matveev, N. A.

    2017-06-01

    Based on the results of experimental investigations in wear resistance increase using lamellar solid lubricants the technology of wear resistance increase of surface elements of friction couples by applying solid lubricants is developed with the following surface plastic deformation providing enough bond strength of solid lubricant with an element surface and increasing operational life.

  8. Stabilized quasi-Newton optimization of noisy potential energy surfaces

    International Nuclear Information System (INIS)

    Schaefer, Bastian; Goedecker, Stefan; Alireza Ghasemi, S.; Roy, Shantanu

    2015-01-01

    Optimizations of atomic positions belong to the most commonly performed tasks in electronic structure calculations. Many simulations like global minimum searches or characterizations of chemical reactions require performing hundreds or thousands of minimizations or saddle computations. To automatize these tasks, optimization algorithms must not only be efficient but also very reliable. Unfortunately, computational noise in forces and energies is inherent to electronic structure codes. This computational noise poses a severe problem to the stability of efficient optimization methods like the limited-memory Broyden–Fletcher–Goldfarb–Shanno algorithm. We here present a technique that allows obtaining significant curvature information of noisy potential energy surfaces. We use this technique to construct both, a stabilized quasi-Newton minimization method and a stabilized quasi-Newton saddle finding approach. We demonstrate with the help of benchmarks that both the minimizer and the saddle finding approach are superior to comparable existing methods

  9. Exploring Multiple Potential Energy Surfaces: Photochemistry of Small Carbonyl Compounds

    Directory of Open Access Journals (Sweden)

    Satoshi Maeda

    2012-01-01

    Full Text Available In theoretical studies of chemical reactions involving multiple potential energy surfaces (PESs such as photochemical reactions, seams of intersection among the PESs often complicate the analysis. In this paper, we review our recipe for exploring multiple PESs by using an automated reaction path search method which has previously been applied to single PESs. Although any such methods for single PESs can be employed in the recipe, the global reaction route mapping (GRRM method was employed in this study. By combining GRRM with the proposed recipe, all critical regions, that is, transition states, conical intersections, intersection seams, and local minima, associated with multiple PESs, can be explored automatically. As illustrative examples, applications to photochemistry of formaldehyde and acetone are described. In these examples as well as in recent applications to other systems, the present approach led to discovery of many unexpected nonadiabatic pathways, by which some complicated experimental data have been explained very clearly.

  10. Effects of geometric modulation and surface potential heterogeneity on electrokinetic flow and solute transport in a microchannel

    Science.gov (United States)

    Bera, Subrata; Bhattacharyya, S.

    2018-04-01

    A numerical investigation is performed on the electroosmotic flow (EOF) in a surface-modulated microchannel to induce enhanced solute mixing. The channel wall is modulated by placing surface-mounted obstacles of trigonometric shape along which the surface potential is considered to be different from the surface potential of the homogeneous part of the wall. The characteristics of the electrokinetic flow are governed by the Laplace equation for the distribution of external electric potential; the Poisson equation for the distribution of induced electric potential; the Nernst-Planck equations for the distribution of ions; and the Navier-Stokes equations for fluid flow simultaneously. These nonlinear coupled set of governing equations are solved numerically by a control volume method over the staggered system. The influence of the geometric modulation of the surface, surface potential heterogeneity and the bulk ionic concentration on the EOF is analyzed. Vortical flow develops near a surface modulation, and it becomes stronger when the surface potential of the modulated region is in opposite sign to the surface potential of the homogeneous part of the channel walls. Vortical flow also depends on the Debye length when the Debye length is in the order of the channel height. Pressure drop along the channel length is higher for a ribbed wall channel compared to the grooved wall case. The pressure drop decreases with the increase in the amplitude for a grooved channel, but increases for a ribbed channel. The mixing index is quantified through the standard deviation of the solute distribution. Our results show that mixing index is higher for the ribbed channel compared to the grooved channel with heterogeneous surface potential. The increase in potential heterogeneity in the modulated region also increases the mixing index in both grooved and ribbed channels. However, the mixing performance, which is the ratio of the mixing index to pressure drop, reduces with the rise in

  11. Near Surface Seismic Reflection Imaging: Great Potential Under Critical Eye

    Science.gov (United States)

    Miller, R. D.; Peterie, S.; Judy, B. E.

    2014-12-01

    Seismic-reflection imaging has long been a mainstay in the oil and gas exploration community with mind boggling advancements in just the last decade, but its application to engineering, environmental, and groundwater problems has not seen the same level of utilization. A great deal of the problem lies in the many assumptions that are valid for deep exploration that are violated in the very complex near surface. Large channel systems with acquisition geometries conducive for both deep and shallow targets are many times assumed to be capable of extending the imaging depth window. In reality, constraints of the source and sensor/recording systems must be considered, where large powerful sources are needed to image exploration depths while low-energy, high-frequency sources are required for the shallow and thin targets in the near surface. Attempts to make one size fit all will result in artifacts that result in bogus images and characterizations in the shallow subsurface.Narrow optimum offsets, highly attenuative materials, extreme velocity variability, wavefield interference, and low signal-to-noise ratios provide an ideal breeding ground for the generation of artifacts on near-surface seismic-reflection data. With the cost of shallow reflection data being so high relative to other geophysical methods and invasive sampling, sometimes a single failure can hinder the growth in the use of the method. The method is extremely powerful and has the potential to provide vast quantities of information critical to understand the distributed hydrogeological and biogeochemical processes that elude borehole investigations. It is imperative that data be acquired in its rawest possible form and be processed with an eye to each operation. Cost savings sometimes result in one-size-fits-all acquisition and automated processing flows. Attention to detail and following signal from origination to characterization is essential.

  12. Increasing potential of biomass burning over Sumatra, Indonesia induced by anthropogenic tropical warming

    International Nuclear Information System (INIS)

    Lestari, R Kartika; Watanabe, Masahiro; Kimoto, Masahide; Imada, Yukiko; Shiogama, Hideo; Field, Robert D; Takemura, Toshihiko

    2014-01-01

    Uncontrolled biomass burning in Indonesia during drought periods damages the landscape, degrades regional air quality, and acts as a disproportionately large source of greenhouse gas emissions. The expansion of forest fires is mostly observed in October in Sumatra favored by persistent droughts during the dry season from June to November. The contribution of anthropogenic warming to the probability of severe droughts is not yet clear. Here, we show evidence that past events in Sumatra were exacerbated by anthropogenic warming and that they will become more frequent under a future emissions scenario. By conducting two sets of atmospheric general circulation model ensemble experiments driven by observed sea surface temperature for 1960–2011, one with and one without an anthropogenic warming component, we found that a recent weakening of the Walker circulation associated with tropical ocean warming increased the probability of severe droughts in Sumatra, despite increasing tropical-mean precipitation. A future increase in the frequency of droughts is then suggested from our analyses of the Coupled Model Intercomparison Project Phase 5 model ensembles. Increasing precipitation to the north of the equator accompanies drier conditions over Indonesia, amplified by enhanced ocean surface warming in the central equatorial Pacific. The resultant precipitation decrease leads to a ∼25% increase in severe drought events from 1951–2000 to 2001–2050. Our results therefore indicate the global warming impact to a potential of wide-spreading forest fires over Indonesia, which requires mitigation policy for disaster prevention. (letter)

  13. Increasing potential of biomass burning over Sumatra, Indonesia induced by anthropogenic tropical warming

    Science.gov (United States)

    Kartika Lestari, R.; Watanabe, Masahiro; Imada, Yukiko; Shiogama, Hideo; Field, Robert D.; Takemura, Toshihiko; Kimoto, Masahide

    2014-10-01

    Uncontrolled biomass burning in Indonesia during drought periods damages the landscape, degrades regional air quality, and acts as a disproportionately large source of greenhouse gas emissions. The expansion of forest fires is mostly observed in October in Sumatra favored by persistent droughts during the dry season from June to November. The contribution of anthropogenic warming to the probability of severe droughts is not yet clear. Here, we show evidence that past events in Sumatra were exacerbated by anthropogenic warming and that they will become more frequent under a future emissions scenario. By conducting two sets of atmospheric general circulation model ensemble experiments driven by observed sea surface temperature for 1960-2011, one with and one without an anthropogenic warming component, we found that a recent weakening of the Walker circulation associated with tropical ocean warming increased the probability of severe droughts in Sumatra, despite increasing tropical-mean precipitation. A future increase in the frequency of droughts is then suggested from our analyses of the Coupled Model Intercomparison Project Phase 5 model ensembles. Increasing precipitation to the north of the equator accompanies drier conditions over Indonesia, amplified by enhanced ocean surface warming in the central equatorial Pacific. The resultant precipitation decrease leads to a ˜25% increase in severe drought events from 1951-2000 to 2001-2050. Our results therefore indicate the global warming impact to a potential of wide-spreading forest fires over Indonesia, which requires mitigation policy for disaster prevention.

  14. InSAR detects increase in surface subsidence caused by an Arctic tundra fire

    Science.gov (United States)

    Liu, Lin; Jafarov, Elchin E.; Schaefer, Kevin M.; Jones, Benjamin M.; Zebker, Howard A.; Williams, Christopher A.; Rogan, John; Zhang, Tingjun

    2014-01-01

    Wildfire is a major disturbance in the Arctic tundra and boreal forests, having a significant impact on soil hydrology, carbon cycling, and permafrost dynamics. This study explores the use of the microwave Interferometric Synthetic Aperture Radar (InSAR) technique to map and quantify ground surface subsidence caused by the Anaktuvuk River fire on the North Slope of Alaska. We detected an increase of up to 8 cm of thaw-season ground subsidence after the fire, which is due to a combination of thickened active layer and permafrost thaw subsidence. Our results illustrate the effectiveness and potential of using InSAR to quantify fire impacts on the Arctic tundra, especially in regions underlain by ice-rich permafrost. Our study also suggests that surface subsidence is a more comprehensive indicator of fire impacts on ice-rich permafrost terrain than changes in active layer thickness alone.

  15. InSAR detects increase in surface subsidence caused by an Arctic tundra fire

    Science.gov (United States)

    Liu, Lin; Jafarov, Elchin E.; Schaefer, Kevin M.; Jones, Benjamin M.; Zebker, Howard A.; Williams, Christopher A.; Rogan, John; Zhang, Tingjun

    2014-06-01

    Wildfire is a major disturbance in the Arctic tundra and boreal forests, having a significant impact on soil hydrology, carbon cycling, and permafrost dynamics. This study explores the use of the microwave Interferometric Synthetic Aperture Radar (InSAR) technique to map and quantify ground surface subsidence caused by the Anaktuvuk River fire on the North Slope of Alaska. We detected an increase of up to 8 cm of thaw-season ground subsidence after the fire, which is due to a combination of thickened active layer and permafrost thaw subsidence. Our results illustrate the effectiveness and potential of using InSAR to quantify fire impacts on the Arctic tundra, especially in regions underlain by ice-rich permafrost. Our study also suggests that surface subsidence is a more comprehensive indicator of fire impacts on ice-rich permafrost terrain than changes in active layer thickness alone.

  16. Osteoinductive potential of demineralized rat bone increases with increasing donor age from birth to adulthood

    DEFF Research Database (Denmark)

    Pinholt, E M; Solheim, E

    1998-01-01

    Demineralized allogenic bone implanted in the subcutis or muscle of rodents causes formation of heterotopic bone by osteoinduction. The osteoinductive response may be weaker in primates than in rodents. It was suggested that the osteoinductive response of demineralized bone for clinical use could...... be enhanced by using young donors, because studies have indicated that the osteoinductive response is reduced in demineralized bone of old versus young donors. However, these findings may not represent a gradual decline in the osteoinductive property of bone matrix throughout the life span. We evaluated...... quantitatively, by uptake of strontium 85, the osteoinductive effect of demineralized bone matrix from newborn, 8-week-old (adolescent), and 8-month-old (adult) male Wistar rats implanted in the abdominal muscles of 8-week-old male Wistar rats. The osteoinductive response increased significantly with increasing...

  17. Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces

    DEFF Research Database (Denmark)

    Gavnholt, Jeppe; Olsen, Thomas; Engelund, Mads

    2008-01-01

    is a density-functional method closely resembling standard density-functional theory (DFT), the only difference being that in Delta SCF one or more electrons are placed in higher lying Kohn-Sham orbitals instead of placing all electrons in the lowest possible orbitals as one does when calculating the ground......-photoemission spectroscopy measurements. This comparison shows that the modified Delta SCF method gives results in close agreement with experiment, significantly closer than the comparable methods. For N2 adsorbed on ruthenium (0001) we map out a two-dimensional part of the potential energy surfaces in the ground state...

  18. Image potential resonances of the aluminum (100) surface; Bildpotentialresonanzen der Aluminium-(100)-Oberflaeche

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Matthias

    2011-07-08

    Image-potential resonances on the (100) surface of pure Aluminum are investigated experimentally and theoretically. The experiments are conducted both energy- and time-resolved using the method of two-photon photoemission spectroscopy. The main attention of the theoretical examination and extensive numerical calculations is devoted to the interaction between surface and bulk states. Image-potential resonances on Al(100) are a system in which a complete series of discrete Rydberg states strongly couples to a continuum of states. As a simple metal it also provides a good opportunity to test theoretical models of the structure of the potential at metal surfaces. This work represents the first high-resolution investigation of image-potential resonances with such strong resonance character. For the first time, it is demonstrated experimentally that isolated image-potential resonances exist on an Aluminum surface. On the (100) surface of Aluminum the second through fifth image-potential resonance are resolved and both, their energies and lifetimes are measured. The binding energies of the image-potential resonances form a Rydberg series of states {epsilon}{sub n}=-(0,85 eV)/((n+a){sup 2}). Within the accuracy of the measurement it is not necessary to introduce a quantum defect a (a=0.022{+-}0.035). Using angle-resolved two-photon photoemission spectroscopy the effective mass of electrons in the second image-potential resonance is measured to 1.01{+-}0.11 electron masses. The lifetimes of the resonances increase as {tau}{sub n} = (1.0{+-}0.2)fs.n{sup 3} starting from n=2. Calculations using the density matrix formalism show that the experimentally observed lifetimes can be explained well by electrons decaying into the bulk. The effect of resonance trapping leads to extended lifetimes in the process. Contrary to common theoretical models of image-potential states at metal surfaces the first image-potential resonance cannot be observed in two-photon photoemission on Al(100

  19. Impact of organic overlayers on a-Si:H/c-Si surface potential

    KAUST Repository

    Seif, Johannes P.

    2017-04-11

    Bilayers of intrinsic and doped hydrogenated amorphous silicon, deposited on crystalline silicon (c-Si) surfaces, simultaneously provide contact passivation and carrier collection in silicon heterojunction solar cells. Recently, we have shown that the presence of overlaying transparent conductive oxides can significantly affect the c-Si surface potential induced by these amorphous silicon stacks. Specifically, deposition on the hole-collecting bilayers can result in an undesired weakening of contact passivation, thereby lowering the achievable fill factor in a finished device. We test here a variety of organic semiconductors of different doping levels, overlaying hydrogenated amorphous silicon layers and silicon-based hole collectors, to mitigate this effect. We find that these materials enhance the c-Si surface potential, leading to increased implied fill factors. This opens opportunities for improved device performance.

  20. An Accurate Potential Energy Surface for H2O

    Science.gov (United States)

    Schwenke, David W.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    We have carried out extensive high quality ab initio electronic structure calculations of the ground state potential energy surface (PES) and dipole moment function (DMF) for H2O. A small adjustment is made to the PES to improve the agreement of line positions from theory and experiment. The theoretical line positions are obtained from variational ro-vibrational calculations using the exact kinetic energy operator. For the lines being fitted, the root-mean-square error was reduced from 6.9 to 0.08 /cm. We were then able to match 30,092 of the 30,117 lines from the HITRAN 96 data base to theoretical lines, and 80% of the line positions differed less than 0.1 /cm. About 3% of the line positions in the experimental data base appear to be incorrect. Theory predicts the existence of many additional weak lines with intensities above the cutoff used in the data base. To obtain results of similar accuracy for HDO, a mass dependent correction to the PH is introduced and is parameterized by simultaneously fitting line positions for HDO and D2O. The mass dependent PH has good predictive value for T2O and HTO. Nonadiabatic effects are not explicitly included. Line strengths for vibrational bands summed over rotational levels usually agree well between theory and experiment, but individual line strengths can differ greatly. A high temperature line list containing about 380 million lines has been generated using the present PES and DMF

  1. Potential Energy Surface of NO on Pt(997: Adsorbed States and Surface Diffusion

    Directory of Open Access Journals (Sweden)

    N. Tsukahara

    2012-01-01

    Full Text Available The potential energy surface (PES of NO on Pt(997 has been elucidated: the adsorption states and diffusion processes of NO on Pt(997 at low coverage were investigated by using infrared reflection absorption spectroscopy (IRAS and scanning tunneling microscopy (STM. When NO molecules adsorb on a surface at a low temperature (11 K, each molecule transiently migrates on the surface from the first impact point to a possible adsorption site. We found that there are four stable adsorption sites for NO on Pt(997: a bridge site of the upper step, an fcc- (or hcp- hollow site of the terrace, an on-top site of the terrace, and an fcc-hollow site of the lower step. At higher temperatures above 45 K, NO molecules start to migrate thermally to more stable adsorption sites on a terrace, and they are finally trapped at the bridge sites of the step, which are the most stable among the four sites.

  2. Nanostructured lipid carrier surface modified with Eudragit RS 100 and its potential ophthalmic functions

    Science.gov (United States)

    Zhang, Wenji; Li, Xuedong; Ye, Tiantian; Chen, Fen; Yu, Shihui; Chen, Jianting; Yang, Xinggang; Yang, Na; Zhang, Jinsong; Liu, Jinlu; Pan, Weisan; Kong, Jun

    2014-01-01

    This study was carried out to evaluate the ocular performance of a cationic Eudragit (EDU) RS 100-coated nanostructured lipid carrier (NLC). The genistein encapsulated NLC (GEN-NLC) was produced using the melt-emulsification technique followed by surface absorption of EDU RS 100. The EDU RS 100 increased the surface zeta potential from −7.46 mV to +13.60 mV, by uniformly forming a spherical coating outside the NLC surface, as shown by transmission electron microscopy images. The EDU RS 100 on the NLC surface effectively improved the NLC stability by inhibiting particle size growth. The obtained EDU RS 100-GEN-NLC showed extended precorneal clearance and a 1.22-fold increase in AUC (area under the curve) compared with the bare NLC in a Gamma scintigraphic evaluation. The EDU RS 100 modification also significantly increased corneal penetration producing a 3.3-fold increase in apparent permeability coefficients (Papp) compared with references. Draize and cytotoxicity testing confirmed that the developed EDU RS 100-GEN-NLC was nonirritant to ocular tissues and nontoxic to corneal cells. These results indicate that the NLC surface modified by EDU RS 100 significantly improves the NLC properties and exhibits many advantages for ocular use. PMID:25246787

  3. Lunar Surface Electric Potential Changes Associated with Traversals through the Earth's Foreshock

    Science.gov (United States)

    Collier, Michael R.; Hills, H. Kent; Stubbs, Timothy J.; Halekas, Jasper S.; Delory, Gregory T.; Espley, Jared; Farrell, William M.; Freeman, John W.; Vondrak, Richard

    2011-01-01

    We report an analysis of one year of Suprathermal Ion Detector Experiment (SIDE) Total Ion Detector (TID) resonance events observed between January 1972 and January 1973. The study includes only those events during which upstream solar wind conditions were readily available. The analysis shows that these events are associated with lunar traversals through the dawn flank of the terrestrial magnetospheric bow shock. We propose that the events result from an increase in lunar surface electric potential effected by secondary electron emission due to primary electrons in the Earth's foreshock region (although primary ions may play a role as well). This work establishes (1) the lunar surface potential changes as the Moon moves through the terrestrial bow shock, (2) the lunar surface achieves potentials in the upstream foreshock region that differ from those in the downstream magnetosheath region, (3) these differences can be explained by the presence of energetic electron beams in the upstream foreshock region and (4) if this explanation is correct, the location of the Moon with respect to the terrestrial bow shock influences lunar surface potential.

  4. Reaction Mechanisms on Multiwell Potential Energy Surfaces in Combustion (and Atmospheric) Chemistry

    International Nuclear Information System (INIS)

    Osborn, David L.

    2017-01-01

    Chemical reactions occurring on a potential energy surface with multiple wells are ubiquitous in low temperature combustion and the oxidation of volatile organic compounds in earth’s atmosphere. The rich variety of structural isomerizations that compete with collisional stabilization make characterizing such complex-forming reactions challenging. This review describes recent experimental and theoretical advances that deliver increasingly complete views of their reaction mechanisms. New methods for creating reactive intermediates coupled with multiplexed measurements provide many experimental observables simultaneously. Automated methods to explore potential energy surfaces can uncover hidden reactive pathways, while master equation methods enable a holistic treatment of both sequential and well-skipping pathways. Our ability to probe and understand nonequilibrium effects and reaction sequences is increasing. These advances provide the fundamental science base for predictive models of combustion and the atmosphere that are crucial to address global challenges.

  5. Reaction Mechanisms on Multiwell Potential Energy Surfaces in Combustion (and Atmospheric) Chemistry

    Science.gov (United States)

    Osborn, David L.

    2017-05-01

    Chemical reactions occurring on a potential energy surface with multiple wells are ubiquitous in low-temperature combustion and in the oxidation of volatile organic compounds in Earth's atmosphere. The rich variety of structural isomerizations that compete with collisional stabilization makes characterizing such complex-forming reactions challenging. This review describes recent experimental and theoretical advances that deliver increasingly complete views of their reaction mechanisms. New methods for creating reactive intermediates coupled with multiplexed measurements provide many experimental observables simultaneously. Automated methods to explore potential energy surfaces can uncover hidden reactive pathways, and master equation methods enable a holistic treatment of both sequential and well-skipping pathways. Our ability to probe and understand nonequilibrium effects and reaction sequences is increasing. These advances provide the fundamental science base for predictive models of combustion and the atmosphere that are crucial to address global challenges.

  6. Antarctic ice shelf potentially stabilized by export of meltwater in surface river

    Science.gov (United States)

    Bell, Robin E.; Chu, Winnie; Kingslake, Jonathan; Das, Indrani; Tedesco, Marco; Tinto, Kirsty J.; Zappa, Christopher J.; Frezzotti, Massimo; Boghosian, Alexandra; Lee, Won Sang

    2017-04-01

    Meltwater stored in ponds and crevasses can weaken and fracture ice shelves, triggering their rapid disintegration. This ice-shelf collapse results in an increased flux of ice from adjacent glaciers and ice streams, thereby raising sea level globally. However, surface rivers forming on ice shelves could potentially export stored meltwater and prevent its destructive effects. Here we present evidence for persistent active drainage networks—interconnected streams, ponds and rivers—on the Nansen Ice Shelf in Antarctica that export a large fraction of the ice shelf’s meltwater into the ocean. We find that active drainage has exported water off the ice surface through waterfalls and dolines for more than a century. The surface river terminates in a 130-metre-wide waterfall that can export the entire annual surface melt over the course of seven days. During warmer melt seasons, these drainage networks adapt to changing environmental conditions by remaining active for longer and exporting more water. Similar networks are present on the ice shelf in front of Petermann Glacier, Greenland, but other systems, such as on the Larsen C and Amery Ice Shelves, retain surface water at present. The underlying reasons for export versus retention remain unclear. Nonetheless our results suggest that, in a future warming climate, surface rivers could export melt off the large ice shelves surrounding Antarctica—contrary to present Antarctic ice-sheet models, which assume that meltwater is stored on the ice surface where it triggers ice-shelf disintegration.

  7. Surface grafted polymer brushes: potential applications in dengue biosensors

    International Nuclear Information System (INIS)

    Baratela, Fernando Jose Costa; Higa, Olga Zazuco; Faria, Henrique Antonio Mendonca de; Queiroz, Alvaro Antonio Alencar de

    2013-01-01

    A polymer brush membrane-based ultrasensitive biosensor for dengue diagnosis was constructed using poly(hydroxyethyl methacrylate) (PHEMA) brushes immobilized onto low density polyethylene (LDPE) films. LDPE surface films were initially modified by Ar + ion irradiation to activate the polymer surface. Subsequently, graft polymerization of 2-hydroxyethyl methacrylate onto the activated LDPE surface was carried out under aqueous conditions to create patterned polymer brushes of PHEMA. The grafted PHEMA brushes were characterized by Fourier transform-infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle analysis. The SEM observations showed that selective surface activation with Ar+ implantation and graft polymerization on the selectively activated surface had occurred. The PHEMA brushes were electrically characterized in the presence of concentrations of human immunoglobulin (IgG). The proposed amperometric biosensor was successfully used for determination of IgG in physiologic samples with excellent responses. (author)

  8. Surface grafted polymer brushes: potential applications in dengue biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Baratela, Fernando Jose Costa; Higa, Olga Zazuco, E-mail: ozahiga@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Faria, Henrique Antonio Mendonca de; Queiroz, Alvaro Antonio Alencar de, E-mail: alencar@unifei.edu.br [Universidade Federal de Itajuba (UNIFEI), Itajuba, MG (Brazil). Instituto de Fisica e Quimica

    2013-07-01

    A polymer brush membrane-based ultrasensitive biosensor for dengue diagnosis was constructed using poly(hydroxyethyl methacrylate) (PHEMA) brushes immobilized onto low density polyethylene (LDPE) films. LDPE surface films were initially modified by Ar{sup +} ion irradiation to activate the polymer surface. Subsequently, graft polymerization of 2-hydroxyethyl methacrylate onto the activated LDPE surface was carried out under aqueous conditions to create patterned polymer brushes of PHEMA. The grafted PHEMA brushes were characterized by Fourier transform-infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle analysis. The SEM observations showed that selective surface activation with Ar+ implantation and graft polymerization on the selectively activated surface had occurred. The PHEMA brushes were electrically characterized in the presence of concentrations of human immunoglobulin (IgG). The proposed amperometric biosensor was successfully used for determination of IgG in physiologic samples with excellent responses. (author)

  9. Surface-active biopolymers from marine bacteria for potential biotechnological applications

    Directory of Open Access Journals (Sweden)

    Karina Sałek

    2016-03-01

    Full Text Available Surface-active agents are amphiphilic chemicals that are used in almost every sector of modern industry, the bulk of which are produced by organo-chemical synthesis. Those produced from biological sources (biosurfactants and bioemulsifiers, however, have gained increasing interest in recent years due to their wide structural and functional diversity, lower toxicities and high biodegradability, compared to their chemically-synthesised counterparts. This review aims to present a general overview on surface-active agents, including their classification, where new types of these biomolecules may lay awaiting discovery, and some of the main bottlenecks for their industrial-scale production. In particular, the marine environment is highlighted as a largely untapped source for discovering new types of surface-active agents. Marine bacteria, especially those living associated with micro-algae (eukaryotic phytoplankton, are a highly promising source of polymeric surface-active agents with potential biotechnological applications. The high uronic acids content of these macromolecules has been linked to conferring them with amphiphilic qualities, and their high structural diversity and polyanionic nature endows them with the potential to exhibit a wide range of functional diversity. Production yields (e.g. by fermentation for most microbial surface-active agents have often been too low to meet the volume demands of industry, and this principally remains as the most important bottleneck for their further commercial development. However, new developments in recombinant and synthetic biology approaches can offer significant promise to alleviate this bottleneck. This review highlights a particular biotope in the marine environment that offers promise for discovering novel surface-active biomolecules, and gives a general overview on specific areas that researchers and the industry could focus work towards increasing the production yields of microbial surface

  10. Investigation of the surface potential of TiO2 (110) by frequency-modulation Kelvin probe force microscopy.

    Science.gov (United States)

    Kou, Lili; Li, Yan Jun; Kamijyo, Takeshi; Naitoh, Yoshitaka; Sugawara, Yasuhiro

    2016-12-16

    We investigate the surface potential distribution on a TiO 2 (110)-1 × 1 surface by Kelvin probe force microscopy (KPFM) and atom-dependent bias-distance spectroscopic mapping. The experimental results demonstrate that the local contact potential difference increases on twofold-coordinated oxygen sites, and decreases on OH defects and fivefold-coordinated Ti sites. We propose a qualitative model to explain the origin of the surface potential of TiO 2 (110). We qualitatively calculate the surface potential induced by chemical potential and permanent surface dipole. The calculated results agree with our experimental ones. Therefore, we suggest that the surface potential of TiO 2 (110) is dominated not only by the permanent surface dipole between the tip apex atom and surface, but also by the dipoles induced by the chemical interaction between the tip and sample. The KPFM technique demonstrate the possibility of investigation of the charge transfer phenomenon on TiO 2 surface under gas conditions. It is useful for the elucidation of the mechanism of the catalytic reactions.

  11. A Survey of the Potential Effects of Increasing UV-B Radiation on the Biosphere. Revision

    National Research Council Canada - National Science Library

    Martin, L

    1998-01-01

    ..., and an increase in UV-B radiation at the surface of the Earth. An increase in UV-B on average would increase the incidence rate of non-melanoma skin cancer worldwide, with an unproved but likely increase in melanoma skin cancer...

  12. Wegner Estimates for Some Random Operators with Anderson-type Surface Potentials

    Science.gov (United States)

    Kitagaki, Yoshihiko

    2010-03-01

    For Schrödinger operator with random potentials concentrated near a surface, Wegner-type estimates are proven by using the spectral averaging method of Combes, Hislop and Klopp. These estimates allow us to show the local regularity of the integrated density of surface states at the gap of the background periodic operator. Acoustic operator with random surface potentials is treated similarly.

  13. Nuclear stimulated desorption as a potential tool for surface study

    International Nuclear Information System (INIS)

    Nir, Dror.

    1993-03-01

    The described research work constitutes a base for an experimental method to be implemented in the study of solid surfaces. Nuclear Stimulated Desorption (NSD) is a new mode of experimentation in thin film and surface physics. It Is based on the interplay between nuclear phenomena (reactions and spontaneous decays), and atomic - scale induced effects on surfaces and very thin films. One may distinguish between two generically different relationships between the two. First, the dynamics of the nuclear reaction -primarily the recoil of the nucleus - may effect the position of the atom or molecule containing it. Second, the nuclear reaction (or decay) may serve as an analytical indicator of the whereabouts of the atom, or molecule, in question. In nuclear stimulated desorption, both thee aspects combine in an essential way. Namely, one employs a series of two consecutive decays (normally weak decays or isomeric transition) . The first of these decays causes the nucleus to desorb from a surface onto which it had been placed; the second serves to determine the position of the daughter and thereby the characteristics of the primary desorption . The essential feature in NSD is that it occurs almost exclusively from the outermost surface layer. This is because we choose to work with nuclei whose recoil energy Is of the same order of magnitude of the binding energy of the atom to the surface . Furthermore, the desorption probability and its angular (and temporal) characteristics, depend on the features (topology, morphology) of its immediate neighborhood. This work describes experiments which were designed to give relevant, phenomenological information about the outgoing flux of the radioactive daughters (for specifically chosen nuclear species) , and in particular the magnitude of the flux, its time dependence and its charged state. In addition. the basic phenomena itself is being distinguished from competing processes (thermal desorption, in particular). We will now

  14. Investigating the time-dependent zeta potential of wood surfaces.

    Science.gov (United States)

    Muff, Livius F; Luxbacher, Thomas; Burgert, Ingo; Michen, Benjamin

    2018-05-15

    This work reports on streaming potential measurements through natural capillaries in wood and investigates the cause of a time-dependent zeta potential measured during the equilibration of wood cell-walls with an electrolyte solution. For the biomaterial, this equilibration phase takes several hours, which is much longer than for many other materials that have been characterized by electrokinetic measurements. During this equilibration phase the zeta potential magnitude is decaying due to two parallel mechanisms: (i) the swelling of the cell-wall which causes a dimensional change reducing the charge density at the capillary interface; (ii) the transport of ions from the electrolyte solution into the permeable cell-wall which alters the electrical potential at the interface by internal charge compensation. The obtained results demonstrate the importance of equilibration kinetics for an accurate determination of the zeta potential, especially for materials that interact strongly with the measurement electrolyte. Moreover, the change in zeta potential with time can be correlated with the bulk swelling of wood if the effect of electrolyte ion diffusion is excluded. This study shows the potential of streaming potential measurements of wood, and possibly of other hygroscopic and nanoporous materials, to reveal kinetic information about their interaction with liquids, such as swelling and ion uptake. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Potential energy surfaces for Ж = , Ne- Ba nuclei

    Indian Academy of Sciences (India)

    112Ba nu- clei in an axially deformed relativistic mean field approach. A quadratic constraint scheme is applied to determine the complete energy surface for a wide range of the quadrupole deformation. The NL3, NL-RA1 and TM1 parameter sets ...

  16. Potential impact of increased temperature and CO2 on particulate dimethylsulfoniopropionate in the Southeastern Bering Sea

    Directory of Open Access Journals (Sweden)

    Peter A. Lee

    2011-06-01

    Full Text Available The potential impact of elevated sea surface temperature (SST and pCO2 on algal community structure and particulate dimethylsulfoniopropionate (DMSPp concentrations in the southeastern Bering Sea was examined using a shipboard “Ecostat” continuous culture system. The ecostat system was used to mimic the conditions projected to exist in the world's oceans by the end of this century (i.e. elevated pCO2 (750 ppm and elevated SST (ambient + 4°C. Two experiments were conducted using natural phytoplankton assemblages from the high-nutrient low-chlorophyll (HNLC central basin and from the middle domain of the southeastern continental shelf. At the HNLC site, the relative abundances of haptophytes and pelagophytes were higher and the relative abundance of diatoms lower under “greenhouse” conditions (i.e. combined 750 ppm CO2 and elevated temperature than control conditions (380 ppm CO2 and ambient temperature. This shift in algal community structure was accompanied by increases in DMSPp (2–3 fold, DMSPp:Chl a (2–3 fold and DMSP:PON (2 fold. At the continental shelf site, the changes in the relative abundances of haptophytes, pelagophytes and diatoms under “greenhouse” conditions were similar to those observed at the HNLC site, with 2.5 fold increases in DMSPp, 50–100% increases in DMSPp:Chl a and 1.8 fold increases in DMSP:PON. At both locations, changes in community structure and the DMSPp parameters were largely driven by increasing temperature. The observed changes were also consistent with the phytoplankton-DMS-albedo climate feedback mechanism proposed in the Charlson-Lovelock-Andreae-Warren (CLAW hypothesis.

  17. Effect of potential attraction term on surface tension of ionic liquids

    Science.gov (United States)

    Vaziri, N.; Khordad, R.; Rezaei, G.

    2018-03-01

    In this work, we have studied the effect of attraction term of molecular potential on surface tension of ionic liquids (ILs). For this purpose, we have introduced two different potential models to obtain analytical expressions for the surface tension of ILs. The introduced potential models have different attraction terms. The obtained surface tensions in this work have been compared with other theoretical methods and also experimental data. Using the calculated surface tension, the sound velocity is also estimated. We have studied the structural effects on the surface tensions of imidazolium-based ionic liquids. It is found that the cation alkyl chain length and the anion size play important roles to the surface tension of the selected ionic liquids. The calculated surface tensions show a good harmony with experimental data. It is clear that the attraction term of molecular potential has an important role on surface tension and sound velocity of our system.

  18. Wright Valley Sediments as Potential Analogs for Martian Surface Processes

    Science.gov (United States)

    Englert, P. A. J.; Bishop, J. L.; Patel, S.; Gibson, E. K.; Koeberl, C.

    2015-12-01

    The Antarctic Dry Valleys (ADV) may provide a unique terrestrial analog for current Martian surface processes. The Wright Valley located in the ADV contains streams, lakes and ponds that host highly saline, sedimentary environments. This project highlights comparisons of formation and salt accumulation processes at the Don Juan Pond (DJP) and Don Quixote Pond (DQP). These are located in the north and south forks of the Wright Valley, which are unique areas where unusual terrestrial processes can be studied. DQP is located in the western part of the north fork about 100 m above mean seawater level. The DQP Valley walls are up to 2500 m high and the brine is seasonally frozen. DJP from the south fork is located ~9 km west of Lake Vanda. The basin floor is 117 m above mean seawater level with activity to the north and south rising above 1000 m. The DJP brine does not freeze and may be a model environment for Ca and Cl weathering and distribution on Mars. Our findings indicate that DJP and DQP have formed in similar climatic and geological environments, but likely experienced different formation conditions. Samples were collected from surface, soil pits and depth profiles during the 1979/1980, the 1990/1991 and the 2005/2006 field seasons. Elemental abundances and mineralogy were evaluated for several sets of sediments. The DJP basin shows low surface abundances of halite and relatively high abundances of sulfates throughout with gypsum or anhydrite dominating at different locations. The DQP area has high surface abundances of halite with gypsum present as the major sulfate. Two models have been proposed to explain these differences: DQP may have formed through a combination of shallow and some deep groundwater influx, while deep groundwater upwelling likely played the dominant role of salt formation at DJP. Our study seeks to understand the formation of DQP and DJP as unique terrestrial processes and as models for Ca, Cl, and S weathering and distribution on Mars.

  19. The potential for using gamification in academic libraries in order to increase student engagement and achievement

    OpenAIRE

    Walsh, Andrew

    2014-01-01

    This paper discusses the potential benefits of using gamification techniques to increase student engagement with library resources. It outlines the link between student use of library resources and academic achievement, and suggests that gamification has to potential to increase usage of resources, which may also increase academic achievement. Some early findings from an implementation of a gamification project, Lemontree, are also discussed in which students reported increased usage of libra...

  20. The Potential for Using Gamification in Academic Libraries in Order to Increase Student Engagement and Achievement

    Directory of Open Access Journals (Sweden)

    Andrew Walsh

    2014-06-01

    Full Text Available This paper discusses the potential benefits of using gamification techniques to increase student engagement with library resources. It outlines the link between student use of library resources and academic achievement, and suggests that gamification has to potential to increase usage of resources, which may also increase academic achievement. Some early findings from an implementation of a gamification project, Lemontree, are also discussed in which students reported increased usage of library resources and their acceptance of gamification techniques in Higher Education.

  1. Fractal analysis as a potential tool for surface morphology of thin films

    Science.gov (United States)

    Soumya, S.; Swapna, M. S.; Raj, Vimal; Mahadevan Pillai, V. P.; Sankararaman, S.

    2017-12-01

    Fractal geometry developed by Mandelbrot has emerged as a potential tool for analyzing complex systems in the diversified fields of science, social science, and technology. Self-similar objects having the same details in different scales are referred to as fractals and are analyzed using the mathematics of non-Euclidean geometry. The present work is an attempt to correlate fractal dimension for surface characterization by Atomic Force Microscopy (AFM). Taking the AFM images of zinc sulphide (ZnS) thin films prepared by pulsed laser deposition (PLD) technique, under different annealing temperatures, the effect of annealing temperature and surface roughness on fractal dimension is studied. The annealing temperature and surface roughness show a strong correlation with fractal dimension. From the regression equation set, the surface roughness at a given annealing temperature can be calculated from the fractal dimension. The AFM images are processed using Photoshop and fractal dimension is calculated by box-counting method. The fractal dimension decreases from 1.986 to 1.633 while the surface roughness increases from 1.110 to 3.427, for a change of annealing temperature 30 ° C to 600 ° C. The images are also analyzed by power spectrum method to find the fractal dimension. The study reveals that the box-counting method gives better results compared to the power spectrum method.

  2. Estimation of Nanodiamond Surface Charge Density from Zeta Potential and Molecular Dynamics Simulations.

    Science.gov (United States)

    Ge, Zhenpeng; Wang, Yi

    2017-04-20

    Molecular dynamics simulations of nanoparticles (NPs) are increasingly used to study their interactions with various biological macromolecules. Such simulations generally require detailed knowledge of the surface composition of the NP under investigation. Even for some well-characterized nanoparticles, however, this knowledge is not always available. An example is nanodiamond, a nanoscale diamond particle with surface dominated by oxygen-containing functional groups. In this work, we explore using the harmonic restraint method developed by Venable et al., to estimate the surface charge density (σ) of nanodiamonds. Based on the Gouy-Chapman theory, we convert the experimentally determined zeta potential of a nanodiamond to an effective charge density (σ eff ), and then use the latter to estimate σ via molecular dynamics simulations. Through scanning a series of nanodiamond models, we show that the above method provides a straightforward protocol to determine the surface charge density of relatively large (> ∼100 nm) NPs. Overall, our results suggest that despite certain limitation, the above protocol can be readily employed to guide the model construction for MD simulations, which is particularly useful when only limited experimental information on the NP surface composition is available to a modeler.

  3. Calculation of the surface potential and surface charge density by measurement of the three-phase contact angle.

    Science.gov (United States)

    Horiuchi, H; Nikolov, A; Wasan, D T

    2012-11-01

    The silica/silicon wafer is widely used in the semiconductor industry in the manufacture of electronic devices, so it is essential to understand its physical chemistry and determine the surface potential at the silica wafer/water interface. However, it is difficult to measure the surface potential of a silica/silicon wafer directly due to its high electric resistance. In the present study, the three-phase contact angle (TPCA) on silica is measured as a function of the pH. The surface potential and surface charge density at the silica/water surface are calculated by a model based on the Young-Lippmann equation in conjunction with the Gouy-Chapman model for the electric double layer. In measurements of the TPCA on silica, two distinct regions were identified with a boundary at pH 9.5-showing a dominance of the surface ionization of silanol groups below pH 9.5 and a dominance of the dissolution of silica into the aqueous solution above pH 9.5. Since the surface chemistry changes above pH 9.5, the model is applied to solutions below pH 9.5 (ionization dominant) for the calculation of the surface potential and surface charge density at the silica/aqueous interface. In order to evaluate the model, a galvanic mica cell was made of a mica sheet and the surface potential was measured directly at the mica/water interface. The model results are also validated by experimental data from the literature, as well as the results obtained by the potentiometric titration method and the electro-kinetic measurements. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Oxathiiranes 8 On the OCS2 Singlet Potential Energy Surface

    DEFF Research Database (Denmark)

    Carlsen, Lars

    1982-01-01

    as the fragmentations of the possible intermediates 1–5 have been studied theoretically within the semiempirical cndo/B framework as conceivable ground-state reactions. On the basis of mo correlations and potential energy changes along the reaction paths, supplementary with previously reported experimental data...

  5. Methods for increasing the biogas potential from the recalcitrant organic matter contained in manure

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Ahring, Birgitte Kiær

    2000-01-01

    The biogas potential of manure could be significantly increased by treatment of the recalcitrant organic matter (biofibers) contained in the manure. Several treatment methods were tested. Mechanical maceration resulted in an average increase of the biogas potential of approximately 17% as shown b...

  6. Methods for increasing the biogas potential from the recalcitrant organic matter contained in manure

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Angelidaki, Irini

    1998-01-01

    The biogas potential of manure could be significantly increased by treatment of the recalcitrant organic matter (biofibers) contained in the manure. Several treatment methods were tested. Mechanical maceration resulted in an average increase of the biogas potential of approx. 17% as shown...

  7. Potential sputtering of target ions by Ar q+, Pb q+ projectiles from a silicon surface

    International Nuclear Information System (INIS)

    Wang, T.S.; Zhao, Y.T.; Peng, H.B.; Wang, S.W.; Fang, Y.; Ding, D.J.; Xiao, G.Q.

    2007-01-01

    Highly charged ions have been expected to be a powerful tool for the surface modification in nano-scale. The potential sputtering of highly charged ions on semi-conductors has the potential to be applied in the micro electronics and nano-technology. In this work, the Ar q+ and Pb q+ ions produced by an electron cyclotron resonance ion source have been used as projectiles to study their potential sputtering on silicon surface. The relative sputtering ion yield is measured with a micro-channel plate, correlated to the incidence angle, charge state and velocity of ions. The experimental results show evidently charge dependence and velocity dependence. The yield induced by the ions changes steeply with the incidence angle, which is much larger than the impact of single charged ion with the same velocity. In the case of Pb 36+ impact, a significant enhancement of the yield has been observed, while the q > 20. At the same time, the yield increases proportionally with the ion velocity. However, in the case of Ar 16+ , the yield decreases versus the increase of the velocity

  8. Calculation of surface potentials at the silica-water interface using molecular dynamics: Challenges and opportunities

    Science.gov (United States)

    Lowe, Benjamin M.; Skylaris, Chris-Kriton; Green, Nicolas G.; Shibuta, Yasushi; Sakata, Toshiya

    2018-04-01

    Continuum-based methods are important in calculating electrostatic properties of interfacial systems such as the electric field and surface potential but are incapable of providing sufficient insight into a range of fundamentally and technologically important phenomena which occur at atomistic length-scales. In this work a molecular dynamics methodology is presented for interfacial electric field and potential calculations. The silica-water interface was chosen as an example system, which is highly relevant for understanding the response of field-effect transistors sensors (FET sensors). Detailed validation work is presented, followed by the simulated surface charge/surface potential relationship. This showed good agreement with experiment at low surface charge density but at high surface charge density the results highlighted challenges presented by an atomistic definition of the surface potential. This methodology will be used to investigate the effect of surface morphology and biomolecule addition; both factors which are challenging using conventional continuum models.

  9. An accurate global potential energy surface, dipole moment surface, and rovibrational frequencies for NH3

    Science.gov (United States)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

    2008-12-01

    A global potential energy surface (PES) that includes short and long range terms has been determined for the NH3 molecule. The singles and doubles coupled-cluster method that includes a perturbational estimate of connected triple excitations and the internally contracted averaged coupled-pair functional electronic structure methods have been used in conjunction with very large correlation-consistent basis sets, including diffuse functions. Extrapolation to the one-particle basis set limit was performed and core correlation and scalar relativistic contributions were included directly, while the diagonal Born-Oppenheimer correction was added. Our best purely ab initio PES, denoted "mixed," is constructed from two PESs which differ in whether the ic-ACPF higher-order correlation correction was added or not. Rovibrational transition energies computed from the mixed PES agree well with experiment and the best previous theoretical studies, but most importantly the quality does not deteriorate even up to 10300cm-1 above the zero-point energy (ZPE). The mixed PES was improved further by empirical refinement using the most reliable J =0-2 rovibrational transitions in the HITRAN 2004 database. Agreement between high-resolution experiment and rovibrational transition energies computed from our refined PES for J =0-6 is excellent. Indeed, the root mean square (rms) error for 13 HITRAN 2004 bands for J =0-2 is 0.023cm-1 and that for each band is always ⩽0.06cm-1. For J =3-5 the rms error is always ⩽0.15cm-1. This agreement means that transition energies computed with our refined PES should be useful in the assignment of new high-resolution NH3 spectra and in correcting mistakes in previous assignments. Ideas for further improvements to our refined PES and for extension to other isotopolog are discussed.

  10. Borneol Is a TRPM8 Agonist that Increases Ocular Surface Wetness.

    Directory of Open Access Journals (Sweden)

    Gui-Lan Chen

    Full Text Available Borneol is a compound widely used in ophthalmic preparations in China. Little is known about its exact role in treating eye diseases. Here we report that transient receptor potential melastatin 8 (TRPM8 channel is a pharmacological target of borneol and mediates its therapeutic effect in the eyes. Ca2+ measurement and electrophysiological recordings revealed that borneol activated TRPM8 channel in a temperature- and dose-dependent manner, which was similar to but less effective than the action of menthol, an established TRPM8 agonist. Borneol significantly increased tear production in guinea pigs without evoking nociceptive responses at 25°C, but failed to induce tear secretion at 35°C. In contrast, menthol evoked tearing response at both 25 and 35°C. TRPM8 channel blockers N-(3-Aminopropyl-2-[(3-methylphenylmethoxy]-N-(2-thienylmethylbenzamide hydrochloride (AMTB and N-(4-tert-butylphenyl-4-(3-chloropyridin-2-ylpiperazine-1-carboxamide (BCTC abolished borneol- and menthol-induced tear secretion. Borneol at micromolar concentrations did not affect the viability of human corneal epithelial cells. We conclude that borneol can activate the cold-sensing TRPM8 channel and modestly increase ocular surface wetness, which suggests it is an active compound in ophthalmic preparations and particularly useful in treating dry eye syndrome.

  11. Erosive potential of energy drinks on the dentine surface.

    Science.gov (United States)

    Pinto, Shelon C S; Bandeca, Matheus C; Silva, Carolina N; Cavassim, Rodrigo; Borges, Alvaro H; Sampaio, José E C

    2013-02-19

    Considering the current high consumption of energy drinks, the aim of the present study is to evaluate the influence of energy drinks in removing the smear layer and exposing dentinal tubules on root surface. Dentine root surfaces were exposed using a diamond bur. Forty movements of scaling were performed in the area prepared in order to create a smear layer. One hundred and thirty specimens were obtained from 35 teeth. Specimens were randomly distributed into 12 groups (n = 10) and divided into subgroups according to the application: topical (n = 5) and friction (n = 5). Twelve energy drinks were evaluated: RedBull, Burn, TNT, Flash Power, Flying Horse, Sports Drink, Ionic, Hot Power, Army Power, Gladiator and Bug. Distilled water was used as a control group. The specimens were analysed by scanning electron microscopy. Topical application: a significant influence of energy drinks on smear layer removal was found for FlyingHorse and Bug when compared with the control group. Friction application: significant smear layer removal was found for Burn, FlyingHorse, Gladiator, SportsDrinks, when compared with the control group. Comparing the different application forms, a statistically significant difference was found for Army Power. Considering the significant smear layer removal, energy drinks can be an important etiological factor for cervical dentine hypersensitivity.

  12. Recent increase in surface fCO2 in the western subtropical North Pacific

    Science.gov (United States)

    Kim, Dongseon; Choi, Yujeong; Kim, Tae-Wook; Park, Geun-Ha

    2017-09-01

    We observed unusually high levels (> 440 μatm) of carbon dioxide fugacity (fCO2) in surface seawater in the western subtropical North Pacific, the area where Subtropical Mode Water is formed, during summer 2015. The NOAA Kuroshio Extension Observatory moored buoy located in this region also measured high CO2 values, up to 500 μatm during this period. These high sea surface fCO2 (fCO2SW) values are explained by much higher normalized total dissolved inorganic carbon and slightly higher normalized total alkalinity concentrations in this region compared to the equatorial Pacific. Moreover, these values are much higher than the climatological CO2 values, even considering increasing atmospheric CO2, indicating a recent large increase in sea surface CO2 concentrations. A large seasonal change in sea surface temperature contributed to higher surface fCO2SW in the summer of 2015.

  13. Influence of surface conductivity on the apparent zeta potential of calcite.

    Science.gov (United States)

    Li, Shuai; Leroy, Philippe; Heberling, Frank; Devau, Nicolas; Jougnot, Damien; Chiaberge, Christophe

    2016-04-15

    Zeta potential is a physicochemical parameter of particular importance in describing the surface electrical properties of charged porous media. However, the zeta potential of calcite is still poorly known because of the difficulty to interpret streaming potential experiments. The Helmholtz-Smoluchowski (HS) equation is widely used to estimate the apparent zeta potential from these experiments. However, this equation neglects the influence of surface conductivity on streaming potential. We present streaming potential and electrical conductivity measurements on a calcite powder in contact with an aqueous NaCl electrolyte. Our streaming potential model corrects the apparent zeta potential of calcite by accounting for the influence of surface conductivity and flow regime. We show that the HS equation seriously underestimates the zeta potential of calcite, particularly when the electrolyte is diluted (ionic strength ⩽ 0.01 M) because of calcite surface conductivity. The basic Stern model successfully predicted the corrected zeta potential by assuming that the zeta potential is located at the outer Helmholtz plane, i.e. without considering a stagnant diffuse layer at the calcite-water interface. The surface conductivity of calcite crystals was inferred from electrical conductivity measurements and computed using our basic Stern model. Surface conductivity was also successfully predicted by our surface complexation model. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Potential surface for the collinear collision of Ne and H/sub 2//sup +/. [eendoergicity, surface parametrization

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, E.F.; Siu, A.K.Q.; Chapman, F.M. Jr.; Matcha, R.L.

    1976-09-01

    A potential energy surface for the Ne--H/sub 2//sup +/ reaction has been obtained in the LCAO--MO--SCF approximation. Analysis of the surface indicates that the reaction Ne+H/sub 2//sup +/..-->..NeH/sup +/+H should proceed with an endoergicity of 12 kcal/mole, in agreement with the experimental results of Chupka and Russell. Several procedures for parameterizing a diatomics-in-molecules (DIM) representation of the NeH/sub 2//sup +/ surface are considered. The results show that an accurate representation of the SCF surface can be obtained from the DIM model using a minimum of diatomic and triatomic data. (AIP)

  15. Resveratrol enhances airway surface liquid depth in sinonasal epithelium by increasing cystic fibrosis transmembrane conductance regulator open probability.

    Directory of Open Access Journals (Sweden)

    Shaoyan Zhang

    Full Text Available Chronic rhinosinusitis engenders enormous morbidity in the general population, and is often refractory to medical intervention. Compounds that augment mucociliary clearance in airway epithelia represent a novel treatment strategy for diseases of mucus stasis. A dominant fluid and electrolyte secretory pathway in the nasal airways is governed by the cystic fibrosis transmembrane conductance regulator (CFTR. The objectives of the present study were to test resveratrol, a strong potentiator of CFTR channel open probability, in preparation for a clinical trial of mucociliary activators in human sinus disease.Primary sinonasal epithelial cells, immortalized bronchoepithelial cells (wild type and F508del CFTR, and HEK293 cells expressing exogenous human CFTR were investigated by Ussing chamber as well as patch clamp technique under non-phosphorylating conditions. Effects on airway surface liquid depth were measured using confocal laser scanning microscopy. Impact on CFTR gene expression was measured by quantitative reverse transcriptase polymerase chain reaction.Resveratrol is a robust CFTR channel potentiator in numerous mammalian species. The compound also activated temperature corrected F508del CFTR and enhanced CFTR-dependent chloride secretion in human sinus epithelium ex vivo to an extent comparable to the recently approved CFTR potentiator, ivacaftor. Using inside out patches from apical membranes of murine cells, resveratrol stimulated an ~8 picosiemens chloride channel consistent with CFTR. This observation was confirmed in HEK293 cells expressing exogenous CFTR. Treatment of sinonasal epithelium resulted in a significant increase in airway surface liquid depth (in µm: 8.08+/-1.68 vs. 6.11+/-0.47,control,p<0.05. There was no increase CFTR mRNA.Resveratrol is a potent chloride secretagogue from the mucosal surface of sinonasal epithelium, and hydrates airway surface liquid by increasing CFTR channel open probability. The foundation for a

  16. Electrohydrodynamics of binary electrolytes driven by modulated surface potentials

    DEFF Research Database (Denmark)

    Mortensen, Asger; Olesen, Laurits Højgaard; Belmon, L.

    2005-01-01

    We study the electrohydrodynamics of the Debye screening layer that arises in an aqueous binary solution near a planar insulating wall when applying a spatially modulated ac voltage. Combining this with first order perturbation theory we establish the governing equations for the full nonequilibrium...... problem and obtain analytic solutions in the bulk for the pressure and velocity fields of the electrolyte and for the electric potential. We find good agreement between the numerics of the full problem and the analytics of the linear theory. Our work provides the theoretical foundations of circuit models...

  17. Intermolecular potential energy surface and thermophysical properties of ethylene oxide

    International Nuclear Information System (INIS)

    Crusius, Johann-Philipp; Hassel, Egon; Hellmann, Robert; Bich, Eckard

    2014-01-01

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C 2 H 4 O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide

  18. Intermolecular potential energy surface and thermophysical properties of ethylene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Crusius, Johann-Philipp, E-mail: johann-philipp.crusius@uni-rostock.de; Hassel, Egon [Lehrstuhl für Technische Thermodynamik, Universität Rostock, 18059 Rostock (Germany); Hellmann, Robert; Bich, Eckard [Institut für Chemie, Universität Rostock, 18059 Rostock (Germany)

    2014-10-28

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C{sub 2}H{sub 4}O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide.

  19. Urbanization increased metal levels in lake surface sediment and catchment topsoil of waterscape parks

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hong-Bo [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Yu, Shen, E-mail: syu@iue.ac.cn [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Li, Gui-Lin [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Liu, Yi; Yu, Guang-Bin [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Deng, Hong [Department of Environmental Sciences, Tiantong National Station of Forest Ecosystem, Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai 200062 (China); Wu, Sheng-Chun [State Key Laboratory in Marine Pollution, Biology and Chemistry Department, City University of Hong Kong, Hong Kong (China); Wong, Ming-Hung [Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Hong Kong (China)

    2012-08-15

    Lake surface sediment is mainly derived from topsoil in its catchment. We hypothesized that distribution of anthropogenic metals would be homogenous in lake surface sediment and the lake's catchment topsoil. Anthropogenic metal distributions (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) in fourteen waterscape parks were investigated in surface sediments and catchment topsoils and possible source homogeneity was tested using stable Pb isotopic ratio analysis. The parks were located along an urbanization gradient consisting of suburban (SU), developing urban (DIU), developed urban (DDU), and central urban core (CUC) areas in Shanghai, China. Results indicated that surface lake sediments and catchment topsoils in the CUC parks were highly contaminated by the investigated anthropogenic metals. Total metal contents in surface sediment and topsoil gradually increased along the urbanization gradient from the SU to CUC areas. Generally, the surface sediments had greater total metal contents than their catchment topsoils. These results suggest that urbanization drives the anthropogenic metal enrichment in both surface sediment and its catchment topsoil in the waterscape parks. Soil fine particles (< 63 {mu}m) and surface sediments had similar enrichment ratios of metals, suggesting that surface runoff might act as a carrier for metals transporting from catchment to lake. Stable Pb isotope ratio analysis revealed that the major anthropogenic Pb source in surface sediment was coal combustion as in the catchment topsoil. Urbanization also correlated with chemical fractionation of metals in both surface sediment and catchment topsoil. From the SU to the CUC parks, amounts of labile metal fractions increased while the residual fraction of those metals remained rather constant. In short, urbanization in Shanghai drives anthropogenic metal distribution in environmental matrices and the sources were homogenous. -- Highlights: Black-Right-Pointing-Pointer Obvious

  20. Urbanization increased metal levels in lake surface sediment and catchment topsoil of waterscape parks

    International Nuclear Information System (INIS)

    Li, Hong-Bo; Yu, Shen; Li, Gui-Lin; Liu, Yi; Yu, Guang-Bin; Deng, Hong; Wu, Sheng-Chun; Wong, Ming-Hung

    2012-01-01

    Lake surface sediment is mainly derived from topsoil in its catchment. We hypothesized that distribution of anthropogenic metals would be homogenous in lake surface sediment and the lake's catchment topsoil. Anthropogenic metal distributions (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) in fourteen waterscape parks were investigated in surface sediments and catchment topsoils and possible source homogeneity was tested using stable Pb isotopic ratio analysis. The parks were located along an urbanization gradient consisting of suburban (SU), developing urban (DIU), developed urban (DDU), and central urban core (CUC) areas in Shanghai, China. Results indicated that surface lake sediments and catchment topsoils in the CUC parks were highly contaminated by the investigated anthropogenic metals. Total metal contents in surface sediment and topsoil gradually increased along the urbanization gradient from the SU to CUC areas. Generally, the surface sediments had greater total metal contents than their catchment topsoils. These results suggest that urbanization drives the anthropogenic metal enrichment in both surface sediment and its catchment topsoil in the waterscape parks. Soil fine particles (< 63 μm) and surface sediments had similar enrichment ratios of metals, suggesting that surface runoff might act as a carrier for metals transporting from catchment to lake. Stable Pb isotope ratio analysis revealed that the major anthropogenic Pb source in surface sediment was coal combustion as in the catchment topsoil. Urbanization also correlated with chemical fractionation of metals in both surface sediment and catchment topsoil. From the SU to the CUC parks, amounts of labile metal fractions increased while the residual fraction of those metals remained rather constant. In short, urbanization in Shanghai drives anthropogenic metal distribution in environmental matrices and the sources were homogenous. -- Highlights: ► Obvious urbanization effect on metal

  1. Ab Initio and DFT Potential Energy Surfaces for Cyanuric Chloride Reactions

    National Research Council Canada - National Science Library

    Pai, Sharmila

    1998-01-01

    ... on the potential energy surface were calculated using the 6-31G and 6-311 +Gbasis sets. DFT(B3LYP) geometry optimizations and zero-point corrections for critical points on the potential energy surface were calculated with the 6-31G, 6-311...

  2. 3D Printed Potential and Free Energy Surfaces for Teaching Fundamental Concepts in Physical Chemistry

    Science.gov (United States)

    Kaliakin, Danil S.; Zaari, Ryan R.; Varganov, Sergey A.

    2015-01-01

    Teaching fundamental physical chemistry concepts such as the potential energy surface, transition state, and reaction path is a challenging task. The traditionally used oversimplified 2D representation of potential and free energy surfaces makes this task even more difficult and often confuses students. We show how this 2D representation can be…

  3. Characterization of electrical conductivity of carbon fiber reinforced plastic using surface potential distribution

    Science.gov (United States)

    Kikunaga, Kazuya; Terasaki, Nao

    2018-04-01

    A new method of evaluating electrical conductivity in a structural material such as carbon fiber reinforced plastic (CFRP) using surface potential is proposed. After the CFRP was charged by corona discharge, the surface potential distribution was measured by scanning a vibrating linear array sensor along the object surface with a high spatial resolution over a short duration. A correlation between the weave pattern of the CFRP and the surface potential distribution was observed. This result indicates that it is possible to evaluate the electrical conductivity of a material comprising conducting and insulating regions.

  4. Prediction of hydrocarbon surface seepage potential using infiltrometer data

    Science.gov (United States)

    Connors, J. J.; Jackson, J. L.; Engle, R. A.; Connors, J. L.

    2017-12-01

    Environmental regulations addressing above-ground storage tank (AST) spill control activities typically require owners/operators to demonstrate that local soil permeability values are low enough to adequately contain released liquids while emergency-response procedures are conducted. Frequently, geotechnical borings and soil samples/analyses, and/or monitoring well slug-test analyses, are used to provide hydraulic conductivity data for the required calculations. While these techniques are useful in assessing hydrological characteristics of the subsurface, they do not always assess the uppermost surface soil layer, where the bulk of the containment can occur. This layer may have been subject to long-term permeability-reduction by activities such as compaction by vehicular and foot traffic, micro-coatings by hydrophobic pollutants, etc. This presentation explores the usefulness of dual-ring infiltrometers, both in field and bench-scale tests, to rapidly acquire actual hydraulic conductivity values of surficial soil layers, which can be much lower than subsurface values determined using more traditional downhole geotechnical and hydrogeological approaches.

  5. Dissociative chemisorption of methane on Ni(111) using a chemically accurate fifteen dimensional potential energy surface.

    Science.gov (United States)

    Zhou, Xueyao; Nattino, Francesco; Zhang, Yaolong; Chen, Jun; Kroes, Geert-Jan; Guo, Hua; Jiang, Bin

    2017-11-22

    A fifteen-dimensional global potential energy surface for the dissociative chemisorption of methane on the rigid Ni(111) surface is developed by a high fidelity fit of ∼200 000 DFT energy points computed using a specific reaction parameter density functional designed to reproduce experimental data. The permutation symmetry and surface periodicity are rigorously enforced using the permutation invariant polynomial-neural network approach. The fitting accuracy of the potential energy surface is thoroughly investigated by examining both static and dynamical attributes of CHD 3 dissociation on the frozen surface. This potential energy surface is expected to be chemically accurate as after correction for surface temperature effects it reproduces the measured initial sticking probabilities of CHD 3 on Ni(111) for various incidence conditions.

  6. Increased fear-potentiated startle in major depressive disorder patients with lifetime history of suicide attempt.

    Science.gov (United States)

    Ballard, Elizabeth D; Ionescu, Dawn F; Vande Voort, Jennifer L; Slonena, Elizabeth E; Franco-Chaves, Jose A; Zarate, Carlos A; Grillon, Christian

    2014-06-01

    Suicide is a common reason for psychiatric emergency and morbidity, with few effective treatments. Anxiety symptoms have emerged as potential modifiable risk factors in the time before a suicide attempt, but few studies have been conducted using laboratory measures of fear and anxiety. We operationally defined fear and anxiety as increased startle reactivity during anticipation of predictable (fear-potentiated startle) and unpredictable (anxiety-potentiated startle) shock. We hypothesized that a lifetime history of suicide attempt (as compared to history of no suicide attempt) would be associated with increased fear-potentiated startle. A post-hoc analysis of fear- and anxiety-potentiated startle was conducted in 28 medication-free patients with Major Depressive Disorder (MDD) divided according to suicide attempt history. The magnitude of fear-potentiated startle was increased in depressed patients with lifetime suicide attempts compared to those without a lifetime history of suicide attempt (F(1,26)=5.629, p=.025). There was no difference in anxiety-potentiated startle by suicide attempt history. This is a post-hoc analysis of previously analyzed patient data from a study of depressed inpatients. Further replication of the finding with a larger patient sample is indicated. Increased fear-potentiated startle in suicide attempters suggests the role of amygdala in depressed patients with a suicide attempt history. Findings highlight the importance of anxiety symptoms in the treatment of patients at increased suicide risk. Published by Elsevier B.V.

  7. Surface recombination of oxygen atoms in O2 plasma at increased pressure: II. Vibrational temperature and surface production of ozone

    Science.gov (United States)

    Lopaev, D. V.; Malykhin, E. M.; Zyryanov, S. M.

    2011-01-01

    Ozone production in an oxygen glow discharge in a quartz tube was studied in the pressure range of 10-50 Torr. The O3 density distribution along the tube diameter was measured by UV absorption spectroscopy, and ozone vibrational temperature TV was found comparing the calculated ab initio absorption spectra with the experimental ones. It has been shown that the O3 production mainly occurs on a tube surface whereas ozone is lost in the tube centre where in contrast the electron and oxygen atom densities are maximal. Two models were used to analyse the obtained results. The first one is a kinetic 1D model for the processes occurring near the tube walls with the participation of the main particles: O(3P), O2, O2(1Δg) and O3 molecules in different vibrational states. The agreement of O3 and O(3P) density profiles and TV calculated in the model with observed ones was reached by varying the single model parameter—ozone production probability (\\gamma_{O_{3}}) on the quartz tube surface on the assumption that O3 production occurs mainly in the surface recombination of physisorbed O(3P) and O2. The phenomenological model of the surface processes with the participation of oxygen atoms and molecules including singlet oxygen molecules was also considered to analyse \\gamma_{O_{3}} data obtained in the kinetic model. A good agreement between the experimental data and the data of both models—the kinetic 1D model and the phenomenological surface model—was obtained in the full range of the studied conditions that allowed consideration of the ozone surface production mechanism in more detail. The important role of singlet oxygen in ozone surface production was shown. The O3 surface production rate directly depends on the density of physisorbed oxygen atoms and molecules and can be high with increasing pressure and energy inputted into plasma while simultaneously keeping the surface temperature low enough. Using the special discharge cell design, such an approach opens up the

  8. Surface recombination of oxygen atoms in O2 plasma at increased pressure: II. Vibrational temperature and surface production of ozone

    International Nuclear Information System (INIS)

    Lopaev, D V; Malykhin, E M; Zyryanov, S M

    2011-01-01

    Ozone production in an oxygen glow discharge in a quartz tube was studied in the pressure range of 10-50 Torr. The O 3 density distribution along the tube diameter was measured by UV absorption spectroscopy, and ozone vibrational temperature T V was found comparing the calculated ab initio absorption spectra with the experimental ones. It has been shown that the O 3 production mainly occurs on a tube surface whereas ozone is lost in the tube centre where in contrast the electron and oxygen atom densities are maximal. Two models were used to analyse the obtained results. The first one is a kinetic 1D model for the processes occurring near the tube walls with the participation of the main particles: O( 3 P), O 2 , O 2 ( 1 Δ g ) and O 3 molecules in different vibrational states. The agreement of O 3 and O( 3 P) density profiles and T V calculated in the model with observed ones was reached by varying the single model parameter-ozone production probability (γ O 3 ) on the quartz tube surface on the assumption that O 3 production occurs mainly in the surface recombination of physisorbed O( 3 P) and O 2 . The phenomenological model of the surface processes with the participation of oxygen atoms and molecules including singlet oxygen molecules was also considered to analyse γ O 3 data obtained in the kinetic model. A good agreement between the experimental data and the data of both models-the kinetic 1D model and the phenomenological surface model-was obtained in the full range of the studied conditions that allowed consideration of the ozone surface production mechanism in more detail. The important role of singlet oxygen in ozone surface production was shown. The O 3 surface production rate directly depends on the density of physisorbed oxygen atoms and molecules and can be high with increasing pressure and energy inputted into plasma while simultaneously keeping the surface temperature low enough. Using the special discharge cell design, such an approach opens up

  9. Constructing Potential Energy Surfaces for Polyatomic Systems: Recent Progress and New Problems

    Directory of Open Access Journals (Sweden)

    J. Espinosa-Garcia

    2012-01-01

    Full Text Available Different methods of constructing potential energy surfaces in polyatomic systems are reviewed, with the emphasis put on fitting, interpolation, and analytical (defined by functional forms approaches, based on quantum chemistry electronic structure calculations. The different approaches are reviewed first, followed by a comparison using the benchmark H + CH4 and the H + NH3 gas-phase hydrogen abstraction reactions. Different kinetics and dynamics properties are analyzed for these reactions and compared with the available experimental data, which permits one to estimate the advantages and disadvantages of each method. Finally, we analyze different problems with increasing difficulty in the potential energy construction: spin-orbit coupling, molecular size, and more complicated reactions with several maxima and minima, which test the soundness and general applicability of each method. We conclude that, although the field of small systems, typically atom-diatom, is mature, there still remains much work to be done in the field of polyatomic systems.

  10. Potential Release of Manufactured Nano Objects During Sanding of Nano-Coated Wood Surfaces.

    Science.gov (United States)

    Fransman, Wouter; Bekker, Cindy; Tromp, Peter; Duis, Willem B

    2016-08-01

    Increasing production and applications of manufactured nano objects (MNOs) have become a source for human exposure and therefore raise concerns and questions about the possible health effects. In this study, the potential release of nano objects, their agglomerates, and aggregates (NOAA) as a result of sanding of hardwood treated with MNOs-containing coating was examined. Two types of MNO-containing coating were compared with untreated hardwood that allowed the evaluation of the influence of the chemical composition on the release of particles. Furthermore, the rotation speed of the sander and the grit size of the sanding paper were varied in order to assess their influence on the release of particles.Measurements were conducted in a gas-tight chamber with a volume of 19.5 m(3) in which ventilation was minimized during experiments. Particle size distributions were assessed by scanning mobility particle sizer , aerodynamic particle sizer, and electrical low pressure impactor. Furthermore, aerosol number concentrations (Nanotracer), active surface area (LQ1), and fractionated mass (Cascade Impactor) were measured before, during, and after sanding. Scanning electron microscope/energy dispersive X-ray (SEM/EDX) analysis was performed to adequately characterize the morphology, size, and chemical composition of released particles.SEM/EDX analysis indicated that sanding surfaces treated with MNO-containing coating did not release the designated MNO as free primary particles. In both coatings, clusters of MNO were perceived embedded in and attached to micro-sized wood and/or coating particles created by sanding the coated surface. Real-time measurements indicated a lower release of micro-sized particles from sanding of surfaces treated with Coating I than from sanding untreated surfaces or surfaces treated with Coating II. A substantial increase in nanosized and a slight increase in micro-sized particles was perceived as the rotation speed of the sander increased. However

  11. Ab initio potential energy and dipole moment surfaces for CS2: determination of molecular vibrational energies.

    Science.gov (United States)

    Pradhan, Ekadashi; Carreón-Macedo, José-Luis; Cuervo, Javier E; Schröder, Markus; Brown, Alex

    2013-08-15

    The ground state potential energy and dipole moment surfaces for CS2 have been determined at the CASPT2/C:cc-pVTZ,S:aug-cc-pV(T+d)Z level of theory. The potential energy surface has been fit to a sum-of-products form using the neural network method with exponential neurons. A generic interface between neural network potential energy surface fitting and the Heidelberg MCTDH software package is demonstrated. The potential energy surface has also been fit using the potfit procedure in MCTDH. For fits to the low-energy regions of the potential, the neural network method requires fewer parameters than potfit to achieve high accuracy; global fits are comparable between the two methods. Using these potential energy surfaces, the vibrational energies have been computed for the four most abundant CS2 isotopomers. These results are compared to experimental and previous theoretical data. The current potential energy surfaces are shown to accurately reproduce the low-lying vibrational energies within a few wavenumbers. Hence, the potential energy and dipole moments surfaces will be useful for future study on the control of quantum dynamics in CS2.

  12. Increased gain of vestibulospinal potentials evoked in neck and leg muscles when standing under height-induced postural threat.

    Science.gov (United States)

    Naranjo, E N; Allum, J H J; Inglis, J T; Carpenter, M G

    2015-05-07

    To measure changes in amplitudes of vestibular evoked myogenic potentials (VEMPs) elicited from neck, upper and lower limb muscles during a quiet standing task with increased postural threat achieved by manipulating surface height. Twenty eight subjects were tested while standing on a platform raised to 0.8 m and 3.2 m from the ground. Surface electromyography was recorded from the ipsilateral sternocleidomastoid (SCM), biceps brachii (BB), flexor carpi radialis (FCR), soleus (SOL) and medial gastrocnemius (MG) muscles. Stimulation was with air-conducted short tone bursts (4 ms). After controlling for background muscle activity, VEMP amplitudes were compared between heights and correlated with changes in state anxiety, fear and arousal. VEMP amplitude significantly increased in SCM (9%) and SOL (12.7%) with increased surface height (pgains. Results demonstrate that VEMPs can be used to test different VSR pathways simultaneously during stance. Since fear and anxiety are prevalent with vestibular disorders, they should be considered as potential contributing factors for clinical vestibular outcome measures. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. Wash-off potential of urban use insecticides on concrete surfaces.

    Science.gov (United States)

    Jiang, Weiying; Lin, Kunde; Haver, Darren; Qin, Sujie; Ayre, Gilboa; Spurlock, Frank; Gan, Jay

    2010-06-01

    Contamination of surface aquatic systems by insecticides is an emerging concern in urban watersheds, but sources of contamination are poorly understood, hindering development of regulatory or mitigation strategies. Hardscapes such as concrete surfaces are considered an important facilitator for pesticide runoff following applications around homes. However, pesticide behavior on concrete has seldom been studied, and standardized evaluation methods are nonexistent. In the present study, a simple batch method for measuring pesticide wash-off potential from concrete surfaces was developed, and the dependence of washable pesticide residues was evaluated on pesticide types, formulations, time exposed to outdoor conditions, and number of washing cycles. After application to concrete, the washable fraction of four pyrethroids (bifenthrin, permethrin, cyfluthrin, and cyhalothrin) and fipronil rapidly decreased, with half-lives residues were still found in the wash-off solution for most treatments after 112 d. The slow decrease may be attributed to a fraction of pesticides being isolated from degradation or volatilization after retention below the concrete surface. Wash-off potential was consistently higher for solid formulations than for liquid formulations, implying an increased runoff contamination risk for granular and powder formulations. Trace levels of pyrethroids were detected in the wash-off solution even after 14 washing-drying cycles over 42 d under outdoor conditions. Results from the present study suggest that pesticide residues remain on concrete and are available for contaminating runoff for a prolonged time. Mechanisms for the long persistence were not clearly known from the present study and merit further investigation. Copyright 2010 SETAC.

  14. Surface Electrical Potentials of Root Cell Plasma Membranes: Implications for Ion Interactions, Rhizotoxicity, and Uptake

    Directory of Open Access Journals (Sweden)

    Yi-Min Wang

    2014-12-01

    Full Text Available Many crop plants are exposed to heavy metals and other metals that may intoxicate the crop plants themselves or consumers of the plants. The rhizotoxicity of heavy metals is influenced strongly by the root cell plasma membrane (PM surface’s electrical potential (ψ0. The usually negative ψ0 is created by negatively charged constituents of the PM. Cations in the rooting medium are attracted to the PM surface and anions are repelled. Addition of ameliorating cations (e.g., Ca2+ and Mg2+ to the rooting medium reduces the effectiveness of cationic toxicants (e.g., Cu2+ and Pb2+ and increases the effectiveness of anionic toxicants (e.g., SeO42− and H2AsO4−. Root growth responses to ions are better correlated with ion activities at PM surfaces ({IZ}0 than with activities in the bulk-phase medium ({IZ}b (IZ denotes an ion with charge Z. Therefore, electrostatic effects play a role in heavy metal toxicity that may exceed the role of site-specific competition between toxicants and ameliorants. Furthermore, ψ0 controls the transport of ions across the PM by influencing both {IZ}0 and the electrical potential difference across the PM from the outer surface to the inner surface (Em,surf. Em,surf is a component of the driving force for ion fluxes across the PM and controls ion-channel voltage gating. Incorporation of {IZ}0 and Em,surf into quantitative models for root metal toxicity and uptake improves risk assessments of toxic metals in the environment. These risk assessments will improve further with future research on the application of electrostatic theory to heavy metal phytotoxicity in natural soils and aquatic environments.

  15. Contrasting optical properties of surface waters across the Fram Strait and its potential biological implications

    DEFF Research Database (Denmark)

    Pavlov, Alexey K.; Granskog, Mats A.; Stedmon, Colin A.

    2015-01-01

    Spitsbergen Current (WSC) differ with regards to temperature, salinity and optical properties. We present data on absorption properties of CDOM and particles across the Fram Strait (along 79° N), comparing Polar and Atlantic surface waters in September 2009 and 2010. CDOM absorption of Polar water in the EGC...... budget in the upper 0-10m shifts across Fram Strait. Under water spectral irradiance profiles were generated using ECOLIGHT 5.4.1 and the results indicate that the shift in composition between dissolved and particulate material does not influence substantially the penetration of photosynthetic active...... radiation (PAR, 400-700nm), but does result in notable differences in ultraviolet (UV) light penetration, with higher attenuation in the EGC. Future changes in the Arctic Ocean system will likely affect EGC through diminishing sea-ice cover and potentially increasing CDOM export due to increase in river...

  16. Mining for diagnostic information in body surface potential maps: A comparison of feature selection techniques

    Directory of Open Access Journals (Sweden)

    McCullagh Paul J

    2005-09-01

    Full Text Available Abstract Background In body surface potential mapping, increased spatial sampling is used to allow more accurate detection of a cardiac abnormality. Although diagnostically superior to more conventional electrocardiographic techniques, the perceived complexity of the Body Surface Potential Map (BSPM acquisition process has prohibited its acceptance in clinical practice. For this reason there is an interest in striking a compromise between the minimum number of electrocardiographic recording sites required to sample the maximum electrocardiographic information. Methods In the current study, several techniques widely used in the domains of data mining and knowledge discovery have been employed to mine for diagnostic information in 192 lead BSPMs. In particular, the Single Variable Classifier (SVC based filter and Sequential Forward Selection (SFS based wrapper approaches to feature selection have been implemented and evaluated. Using a set of recordings from 116 subjects, the diagnostic ability of subsets of 3, 6, 9, 12, 24 and 32 electrocardiographic recording sites have been evaluated based on their ability to correctly asses the presence or absence of Myocardial Infarction (MI. Results It was observed that the wrapper approach, using sequential forward selection and a 5 nearest neighbour classifier, was capable of choosing a set of 24 recording sites that could correctly classify 82.8% of BSPMs. Although the filter method performed slightly less favourably, the performance was comparable with a classification accuracy of 79.3%. In addition, experiments were conducted to show how (a features chosen using the wrapper approach were specific to the classifier used in the selection model, and (b lead subsets chosen were not necessarily unique. Conclusion It was concluded that both the filter and wrapper approaches adopted were suitable for guiding the choice of recording sites useful for determining the presence of MI. It should be noted however

  17. Hypoxia enhances proliferation through increase of colony formation rate with chondrogenic potential in primary synovial mesenchymal stem cells.

    Science.gov (United States)

    Ohara, Toshiyuki; Muneta, Takeshi; Nakagawa, Yusuke; Matsukura, Yu; Ichinose, Shizuko; Koga, Hideyuki; Tsuji, Kunikazu; Sekiya, Ichiro

    2016-01-01

    Synovial mesenchymal stem cells (MSCs) are an attractive cell source for cartilage and meniscus regeneration. Use of primary MSCs is the preferable because these cells are safer than cells passaged several times in terms of probability of chromosome abnormalities. The effect of hypoxia on the proliferation of MSCs is controversial and remains unknown in primary synovial MSCs. Primary synovial MSCs were cultured at normoxia or hypoxia, and colony number, cell number, surface epitopes, mitochondria activity, TEM finding, and chondrogenic potential were analyzed. To investigate the effect of hypoxia on attachment of synovial MSCs, cells were cultured at hypoxia for the first 3 days, then cultured at normoxia. To investigate the effect of hypoxia on proliferation, cells were also cultured at hypoxia for the last 11 days. Hypoxia increased colony number and cell number per dish in primary synovial MSCs. Hypoxia did not affect cell number per colony, surface epitopes, mitochondria activity, TEM finding or chondrogenic potential. Hypoxia for the first 3 days did not alter colony number per dish or cell number per dish, while hypoxia for the last 11 days increased. Hypoxia enhanced proliferation through increase of colony formation rate with chondrogenic potential in primary synovial MSCs.

  18. Effects of flexoelectricity and surface elasticity on piezoelectric potential in a bent ZnO nanowire

    Science.gov (United States)

    Zhang, Shuangzhe; Yao, Haiyan; Fan, Wenliang; Hao, Yu; Wu, Xudong; Hou, Dongyuan

    2017-01-01

    In this work, a rapid model is established to study the effects of flexoelectricity and surface elasticity on the piezoelectric potential of a bent ZnO nanowire. Based on the piezoelectric theory and core-surface model, the distribution of piezoelectric potential of the ZnO nanowire is investigated. The analytical solution shows that the flexoelectricity and surface elasticity both significantly influence the piezoelectric potential. However, the effect of flexoelectricity is longitudinal dependent, which vanishes on the top side of nanowire, but only left surface elasticity effect on the potential. Simulation results show that the maximum value of potential on the top side of nanowire is about ± 220.5mV, of which result is lower compared to other theoretical models, but it should be more reasonable.

  19. Potential sputtering from a Si surface by very highly charged ion impact

    International Nuclear Information System (INIS)

    Tona, Masahide; Watanabe, Hirofumi; Takahashi, Satoshi; Nakamura, Nobuyuki; Yoshiyasu, Nobuo; Sakurai, Makoto; Yamada, Chikashi; Ohtani, Shunsuke

    2007-01-01

    We have observed radiation effect in collision of slow highly charged ions with the following target materials; a SiO 2 thin film, a Si(1 1 1)-(7 x 7) surface and a hydrogen terminated Si(1 1 1)-(1 x 1) surface. Secondary ion mass spectrometry and scanning tunneling microscopy revealed some features due to 'potential sputtering'; (a) strong dependence of secondary particle emission on the surface condition, (b) high yield of positive ion emission including cluster fragments and (c) creation of nanometer sized surface structure. The mechanism for the potential sputtering is briefly discussed, based on the 'Coulomb explosion' model

  20. Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering.

    Science.gov (United States)

    Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S; Techert, Simone; Strocov, Vladimir N; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander

    2016-01-29

    Thermally driven chemistry as well as materials' functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future.

  1. Evaluation of Surface Water Harvesting Potential in Aq Emam Watershed System in the Golestan Province

    Directory of Open Access Journals (Sweden)

    s. nazaryan

    2016-02-01

    Full Text Available Introduction : Given its low and sparse precipitation both in spatial and temporal scales, Iran is nestled in an arid and semiarid part of the world. On the other hand, because of population growth, urbanization and the development of agriculture and industry sector is frequently encountered with increasing water demand. The increasing trend of water demand will widen the gap between water supply and demand in the future. This, in turn, necessitates urgent attention to the fundamentals of economic planning and allocation of water resources. Considering the limited resources and the declining water table and salinization of groundwater, especially in semi-arid areas forces us to exploit surface waters. When we evaluate the various methods of collecting rainwater, surface water that is the outcome of rainfall-runoff responses in a basin, is found to be a potential source of water and it can be useful to meet some of our water demand if managed properly. Water shortages in arid areas are critical, serious and persistent. Thus, water harvesting is an effective and economic goal. The most important step in the implementation of rain water harvesting systems is proper site selection that could cause significant savings in time and cost. In this study the potential of surface waters in the Aq Emam catchment in the east Golestan province was evaluated. The purpose of this study is to provide a framework for locating areas with water harvesting potential. Materials and Methods: For spatial evaluation of potential runoff, first, the amount of runoff is calculated using curve number and runoff potential maps were prepared with three classes: namely, the potential for low, medium and high levels. Finally, to identify suitable areas for rain water harvesting, rainfall maps, soil texture, slope and land use were weighted and multiplied based on their importance in order to determine the appropriate areas to collect runoff Results and Discussion : The results

  2. Direct Measurement of Surface Dissolution Rates in Potential Nuclear Waste Forms: The Example of Pyrochlore.

    Science.gov (United States)

    Fischer, Cornelius; Finkeldei, Sarah; Brandt, Felix; Bosbach, Dirk; Luttge, Andreas

    2015-08-19

    The long-term stability of ceramic materials that are considered as potential nuclear waste forms is governed by heterogeneous surface reactivity. Thus, instead of a mean rate, the identification of one or more dominant contributors to the overall dissolution rate is the key to predict the stability of waste forms quantitatively. Direct surface measurements by vertical scanning interferometry (VSI) and their analysis via material flux maps and resulting dissolution rate spectra provide data about dominant rate contributors and their variability over time. Using pyrochlore (Nd2Zr2O7) pellet dissolution under acidic conditions as an example, we demonstrate the identification and quantification of dissolution rate contributors, based on VSI data and rate spectrum analysis. Heterogeneous surface alteration of pyrochlore varies by a factor of about 5 and additional material loss by chemo-mechanical grain pull-out within the uppermost grain layer. We identified four different rate contributors that are responsible for the observed dissolution rate range of single grains. Our new concept offers the opportunity to increase our mechanistic understanding and to predict quantitatively the alteration of ceramic waste forms.

  3. The potential of agricultural practices to increase C storage in cropped soils: an assessment for France

    Science.gov (United States)

    Chenu, Claire; Angers, Denis; Métay, Aurélie; Colnenne, Caroline; Klumpp, Katja; Bamière, Laure; Pardon, Lenaic; Pellerin, Sylvain

    2014-05-01

    Though large progress has been achieved in the last decades, net GHG emissions from the agricultural sector are still more poorly quantified than in other sectors. In this study, we examined i) technical mitigation options likely to store carbon in agricultural soils, ii) their potential of additional C storage per unit surface area and iii) applicable areas in mainland France. We considered only agricultural practices being technically feasible by farmers and involving no major change in either production systems or production levels. Moreover, only currently available techniques with validated efficiencies and presenting no major negative environmental impacts were taken into account. Four measures were expected to store additional C in agricultural soils: - Reducing tillage: either a switch to continuous direct seeding, direct seeding with occasional tillage once every five years, or continuous superficial (20yrs) C storage rates (MgC ha-1 y-1,) of cropping systems with and without the proposed practice. Then we analysed the conditions for potential application, in terms of feasibility, acceptance, limitation of yield losses and of other GHG emissions. According to the literature, additional C storage rates were 0.15 (0-0.3) MgC ha-1 y-1 for continuous direct seeding, 0.10 (0-0.2) MgC ha-1 y-1for occasional tillage one year in five, and 0.0 MgC ha-1 y-1 for superficial tillage. Cover crops were estimated to store 0.24 (0.13-0.37) MgC ha-1 y-1 between cash crops and 0.49 (0.23-0.72) MgC ha-1 y-1 when associated with vineyards. Hedges (i.e 60 m ha-1) stored 0.15 (0.05-0.26) Mg C ha-1 y-1. Very few estimates were available for temperate agroforestry system, and we proposed a value of 1.01 (0.11-1.36) Mg C ha-1 y-1for C stored in soil and in the tree biomass for systems comprising 30-50 trees ha-1. Increasing the life time of temporary sown grassland increased C stocls by 0.11 (0.07-0.22) Mg C ha-1 y-1. In general, practices with increased C inputs to soil through

  4. A method for increasing the surface area of perovskite-type oxides

    Indian Academy of Sciences (India)

    combustion of methane at different temperatures (450–600oC) has been thoroughly investigated. The hydrothermal treatments result in the activation of the perovskite oxides by increasing their surface area very markedly. Keywords. ABO3-type perovskite oxides; LaCoO3; LaMnO3; hydrothermal treatment; catalytic ...

  5. A method for increasing the surface area of perovskite-type oxides

    Indian Academy of Sciences (India)

    700oC (v), 800oC ( ) and without water treatment (U). The increase in the surface area of the perovskite-type oxides and the observed decrease in the crystal size by the steam treatment at 350–800oC are expected because of the recrystallization during the high temperature hydrothermal treatment depending upon the.

  6. How Conjunctive Use of Surface and Ground Water could Increase Resiliency in US?

    Science.gov (United States)

    Josset, L.; Rising, J. A.; Russo, T. A.; Troy, T. J.; Lall, U.; Allaire, M.

    2016-12-01

    evaluation of stresses on water resources. We explore in particular geographic and temporal trends in function of user-types to develop a better understanding of the dynamics at play. We conclude with a comparison between the optimization results and current water use to identify potential solutions to increase resiliency.

  7. Hot-electron-mediated desorption rates calculated from excited-state potential energy surfaces

    DEFF Research Database (Denmark)

    Olsen, Thomas; Gavnholt, Jeppe; Schiøtz, Jakob

    2009-01-01

    We present a model for desorption induced by (multiple) electronic transitions [DIET (DIMET)] based on potential energy surfaces calculated with the delta self-consistent field extension of density-functional theory. We calculate potential energy surfaces of CO and NO molecules adsorbed on various...... transition-metal surfaces and show that classical nuclear dynamics does not suffice for propagation in the excited state. We present a simple Hamiltonian describing the system with parameters obtained from the excited-state potential energy surface and show that this model can describe desorption dynamics...... in both the DIET and DIMET regimes and reproduce the power-law behavior observed experimentally. We observe that the internal stretch degree of freedom in the molecules is crucial for the energy transfer between the hot electrons and the molecule when the coupling to the surface is strong....

  8. Potential feedbacks between snow cover, soil moisture and surface energy fluxes in Southern Norway

    Science.gov (United States)

    Brox Nilsen, Irene; Tallaksen, Lena M.; Stordal, Frode

    2017-04-01

    At high latitudes, the snow season has become shorter during the past decades because snowmelt is highly sensitive to a warmer climate. Snowmelt influences the energy balance by changing the albedo and the partitioning between latent and sensible heat fluxes. It further influences the water balance by changing the runoff and soil moisture. In a previous study, we identified southern Norway as a region where significant temperature changes in summer could potentially be explained by land-atmosphere interactions. In this study we hypothesise that changes in snow cover would influence the summer surface fluxes in the succeeding weeks or months. The exceptionally warm summer of 2014 was chosen as a test bed. In Norway, evapotranspiration is not soil moisture limited, but energy limited, under normal conditions. During warm summers, however, such as in 2014, evapotranspiration can be restricted by the available soil moisture. Using the Weather Research and Forecasting (WRF) model we replace the initial ground conditions for 2014 with conditions representative of a snow-poor spring and a snow-rich spring. WRF was coupled to Noah-MP at 3 km horizontal resolution in the inner domain, and the simulations covered mid-May through September 2014. Boundary conditions used to force WRF were taken from the Era-Interim reanalysis. Snow, runoff, soil moisture and soil temperature observational data were provided by the Norwegian Water Resources and Energy Directorate for validation. The validation shows generally good agreement with observations. Preliminary results show that the reduced snowpack, hereafter "sim1" increased the air temperature by up to 5 K and the surface temperature by up to 10 K in areas affected by snow changes. The increased snowpack, hereafter "sim2", decreased the air and surface temperature by the same amount. These are weekly mean values for the first eight simulation weeks from mid May. Because of the higher net energy available ( 100 Wm-2) in sim 1, both

  9. Surface potential effects in low-energy current image diffraction patterns observed on the Al(001) surface

    International Nuclear Information System (INIS)

    Fine structure observed in high-resolution low-energy electron diffraction (LEED) measurements near the energy threshold for emergence of new beams has been attributed to surface barrier effects. Recently, the surface barrier has been suggested as the source of the fine structure observed in current image diffraction (CID) patterns obtained by rastering the primary beam across an Al(001) crystal surface at a constant energy. This suggestion was based on kinematic arguments which correlated the emergence angle for a new electron beam with the observed structure in the CID pattern. In this work, the angular dependence of the elastic component of the total crystal reflectivity is calculated at constant energy. The calculations are based on full dynamical theories such as used in LEED but incorporating different surface barrier models to account for the saturating image potential. The results are compared with the experimental CID results

  10. Influence of an Increasing Surface Melt Over Decadal Timescales on Land Terminating Outlet Glaciers

    Science.gov (United States)

    Gagliardini, O.; Werder, M. A.; Durand, G.

    2015-12-01

    During the last decades, Greenland surface melt has shown an increase both in intensity and spatial extent. Part of this water probably reaches the bedrock and enhances the glacier speed, advecting larger volume of ice into the ablation area. In the context of a warming climate, this mechanism will contribute to the future rate of retreat and thinning of the land-terminating glaciers of Greenland. Complex couplings, implying both positive and negative feedbacks, prevail between surface mass balance, ice flow, basal hydrology and the evolution of the glacier geometry. Larger amount of melt water might increase or decrease the mean ice flow of a glacier, depending on the capacity of the basal hydrology network to evacuate this surplus of water, which in turn will influence the surface crevassing and the ability of water to reach the bedrock at higher elevations. Here, using a coupled basal hydrology and prognostic ice flow model, the evolution of a Greenland-type glacier subject to an increasing surface melt is studied over few decades. The basal hydrology model, based on the GlaDS model, includes an inefficient cavity-type water sheet and a network of efficient discrete channels. Both systems are connected and evolve in time in response to the water inputs. The prognostic equations for ice flow and the hydrology model are implemented in the open source, finite element, ice sheet / ice flow model Elmer/Ice. Assuming a surface melt increase over the next decades, the evolution of crevassed areas and the ability of water to reach the bedrock is inferred. Our results indicate that the currently observed crevasse distribution is likely to extend upstream, leading to an increase in ice flow which, in turn, accelerates the retreat and thinning of land-terminating glaciers.

  11. Potentiating the antibacterial effect of silver nanospheres by surface-capping with chlorhexidine gluconate

    Energy Technology Data Exchange (ETDEWEB)

    Priyadarshini, Balasankar Meera; Fawzy, Amr S., E-mail: denasfmf@nus.edu.sg [National University of Singapore, Discipline of Oral Sciences, Faculty of Dentistry (Singapore)

    2017-04-15

    In this work, the commercial polyvinylpyrrolidone (PVP)-capped silver nanospheres (Ag-NSP) were surface decorated with chlorhexidine gluconate (CHXg) for potentiating the antibacterial properties of Ag-NSP. Different formulations of CHXg-loaded Ag-NSP (Ag-NSP/CHXg) were prepared by varying the incubation times (0.5, 1.5, and 3 h). A thorough characterization of Ag-NSP/CHXg nanospheres has been carried out by dynamic light scattering (DLS), transmission electron microscopy (TEM), energy-dispersive surface elemental composition spectral analysis (SEM/EDX), Fourier transform infrared spectroscopy (FTIR), percentage (%) CHXg loading efficiency (LE), in vitro CHXg and Ag{sup +} ion release, antibacterial/biofilm inhibition assay, and human mesenchymal stem cells (hMSCs) cytotoxicity evaluation. DLS measured nanospheres to be <160 nm and indicated that CHXg treatment drastically shifted the surface charge from negative to high positive values, with homogenous distribution. TEM revealed spherical Ag-NSP/CHXg nanospheres with a clearly visible surface coating of CHXg. FTIR confirmed association of CHXg with Ag-NSP nanospheres, whereas SEM/EDX data verified presence of spectral peaks specific to silver (Ag), CHXg, and PVP. The %LE gradually increased with increasing incubation times. In vitro CHXg release exhibited a bi-phasic fashion showing maximum release of ~74.83 ± 20.67% from Ag-NSP/CHXg-3h at 14 days. A slow release of Ag{sup +} ions was detected; however, the surface decoration of Ag-NSP substantially hampered/restricted the liberation of ions. Agar well diffusion, MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl) -2H–tetrazolium), and crystal violet assay suggested good antibacterial/antibiofilm activity of Ag-NSP/CHXg that correlated with the increasing %LE of nanospheres. hMSCs cytotoxicity study showed low toxicity properties of all nanosphere formulations, except for Ag-NSP/CHXg-3h, affecting the cell viability at all

  12. Mixed Potential Energy Surfaces of the Ultrafast Isomerization of Retinal in Bacteriorhodopsin

    OpenAIRE

    Prokhorenko Valentyn I.; Morizumi Takefumi; Halpin Alexei; Johnson Philip J. M.; Ernst Oliver P.; Dwayne Miller R. J.

    2013-01-01

    We observe, using electronic two-dimensional photon echo spectroscopy, that the cis and trans potential energy surfaces of the ultrafast isomerization of retinal in bacteriorhodopsin are mixed via the hydrogen out of plane (HOOP) mode.

  13. Mixed Potential Energy Surfaces of the Ultrafast Isomerization of Retinal in Bacteriorhodopsin

    Directory of Open Access Journals (Sweden)

    Prokhorenko Valentyn I.

    2013-03-01

    Full Text Available We observe, using electronic two-dimensional photon echo spectroscopy, that the cis and trans potential energy surfaces of the ultrafast isomerization of retinal in bacteriorhodopsin are mixed via the hydrogen out of plane (HOOP mode.

  14. Quantum Nuclear Extension of Electron Nuclear Dynamics on Folded Effective-Potential Surfaces

    DEFF Research Database (Denmark)

    Hall, B.; Deumens, E.; Ohrn, Y.

    2014-01-01

    A perennial problem in quantum scattering calculations is accurate theoretical treatment of low energy collisions. We propose a method of extracting a folded, nonadiabatic, effective potential energy surface from electron nuclear dynamics (END) trajectories; we then perform nuclear wave packet...

  15. Reforming of Regional Fiscal Policy as Basis of Increasing Taxation Potential of Territories

    OpenAIRE

    Igonina, Lyudmila Lazarevna; Nabiyev, Ramazan Abdulmuminovich; Alimirzoeva, Madina Gamidulakhovna; Gulmagomedova, Gulzar Akhmedullakhovna; Suleymanov, Magomed Magomedovich

    2016-01-01

    The article is devoted to researching problems related to forming regional fiscal policy focused on increasing the taxation potential of territories. The subject of the research is theoretic and methodological basics of pursuing regional fiscal policy focused on developing the taxation potential of the Russian Federation regions. The object of the research is the Russian taxation system, regional fiscal policy, and foreign and national practices of taxation regulation of regional development....

  16. A System Model of Increasing the Investment Potential of Technologically Unrelated Sectors

    Directory of Open Access Journals (Sweden)

    Melnyk Alexander G.

    2016-02-01

    Full Text Available The article presents a theoretical substantiation and the progress of practical application of the method for evaluating lagged effects of increasing the investment potential of interaction between industries in meso-level innovation systems on the example of the high-tech sector of Ukraine. The interaction data are considered in terms of their formation in such technologically unrelated sectors as the industrial sector and sector of education and sciences. It has been determined that the analytical basis to form the models of increasing the investment potential in innovation systems of meso-level should be presented by a comprehensive integrated assessment of all sectors involved in the reproduction process including technologically unrelated sectors of highly structured innovative systems. There has been proposed a system model of increasing the investment potential of the high-tech sector taking into account the optimization and synergy effects for system decisions concerning technologically unrelated sectors in economic systems of innovation type of reproduction.

  17. First Principle Calculation of Electronic, Optical Properties and Photocatalytic Potential of CuO Surfaces

    OpenAIRE

    Ahmad, Faozan

    2016-01-01

    We have performed DFT calculations of electronic structure, optical properties and photocatalytic potential of the low-index surfaces of CuO. Photocatalytic reaction on the surface of semiconductor requires the appropriate band edge of the semiconductor surface to drive redox reactions. The calculation begins with the electronic structure of bulk system; it aims to determine realistic input parameters and band gap prediction. CuO is an antiferromagnetic material with strong electronic correla...

  18. [Age-related characteristics of the surface bioelectrical potential of human, canine and rat teeth and features of its distribution over the surface of the crown].

    Science.gov (United States)

    Donskiĭ, G I; Pavliuchenko, O N; Palamarchuk, Iu N; Makarova, N Ia

    1989-01-01

    Using a digital electron voltmeter, bioelectrical potentials (BEPs) of dental crowns have been recorded in 180 patients, 36 dogs, and 93 white non-inbred rats. It has been established that the surface BEP is a marker of dental enamel maturation and does not depend on the species of mammals. On the other hand maturation processes differ in their rate on the cutting edge, equator, and neck: with advancing age algebraic difference between the magnitudes of surface BEPs decreases in humans and increases in dogs and rats.

  19. The sand extraction potential of embedded land surface lowering in the Netherlands

    NARCIS (Netherlands)

    Meulen, M.J. van der; Kleine, M.P.E. de; Veldkamp, J.G.; Dubelaar, C.W.; Pietersen, H.S.

    2004-01-01

    In the Netherlands, mineral extraction by means of dredging or quarrying meets with considerable societal resistance. Land surface lowering prior to large land reconstruction projects may raise fewer objections. We have calculated the potential yields of sand and gravel from land surface lowering

  20. The sand extraction potential of embedded land surface lowering in the Netherlands

    NARCIS (Netherlands)

    Van der Meulen, M.J.; De Kleine, M.P.E.; Veldkamp, J.G.; Dubbelaar, C.W.; Pietersen, H.S.

    2004-01-01

    In the Netherlands, mineral extraction by means of dredging or quarrying meets with considerable societal resistance. Land surface lowering prior to large land reconstruction projects may raise fewer objections. We have calculated the potential yields of sand and gravel form land surface lowering

  1. Characterization of the surface of protein-adsorbed dental materials by wetting and streaming potential measurements

    NARCIS (Netherlands)

    Matsumura, H.; Kawasaki, K.; Okumura, N.; Kambara, M.; Norde, W.

    2003-01-01

    In this study we have elucidated the water-wettability and the electrokinetic surface potential of protein-covered dental materials. The proteins used here as typical proteins were human serum albumin and lysozyme from hen*s egg. The wettability (hydrophobicity/hydrophilicity) and the surface

  2. Characterization of the surface of protein-adsorbed dental materials by wetting and streaming potential measurements

    NARCIS (Netherlands)

    Matsumura, H; Kawasaki, K; Okumura, N; Kambara, M; Norde, W

    2003-01-01

    In this study we have elucidated the water-wettability and the electrokinetic surface potential of protein-covered dental materials. The proteins used here as typical proteins were human serum albumin and lysozyme from hen's egg. The wettability (hydrophobicity/hydrophilicity) and the surface

  3. Hydrophobicity, surface tension, and zeta potential measurements of glass-reinforced hydroxyapatite composites.

    Science.gov (United States)

    Lopes, M A; Monteiro, F J; Santos, J D; Serro, A P; Saramago, B

    1999-06-15

    Wettability and zeta potential studies were performed to characterize the hydrophobicity, surface tension, and surface charge of P2O5-glass-reinforced hydroxyapatite composites. Quantitative phase analysis was performed by the Rietveld method using GSAS software applied to X-ray diffractograms. Surface charge was assessed by zeta potential measurements. Protein adsorption studies were performed using vitronectin. Contact angles and surface tensions variation with time were determined by the sessile and pendent drop techniques, respectively, using ADSA-P software. The highest (-18.1 mV) and lowest (-28.7 mV) values of zeta potential were found for hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP), respectively, with composite materials presenting values in between. All studied bioceramic materials showed similar solid surface tension. For HA and beta-TCP, solid surface tensions of 46.7 and 45.3 mJ/m2, respectively, were obtained, while composites presented intermediate surface tension values. The dispersive component of surface tension was the predominant one for all materials studied. Adhesion work values between the vitronectin solution and HA and beta-TCP were found to be 79.8 and 88.0 mJ/m2, respectively, while the 4.0 wt % glass composites showed slightly lower values than the 2.5 wt % ones. The presence of beta-TCP influenced surface charge, hydrophobicity, and protein adsorption of the glass-reinforced HA composites, and therefore indirectly affected cell-biomaterial interactions.

  4. WAYS TO INCREASE LEVERAGE RURAL TOURISM POTENTIAL OF THE HISTORICAL REGIONS CRIŞANA

    Directory of Open Access Journals (Sweden)

    BARBU IONEL

    2014-12-01

    Full Text Available In this work we aimed to identify some ways of increasing the recovery of the tourism potential of the historical region Crisan. Given the multitude of economic implications, socio-cultural and environmental impacts of rural tourism by increasing recovery tourist potential, the positive impact of this economic activity will be felt by all concerned: residents, entrepreneurs, tourists and local public administration. By the way, tourists will benefit a greater diversity of services for accommodation, dining and leisure, causing them to disseminate their opinions among other tourists and even return to those places.

  5. Increasing potential for intense tropical and subtropical thunderstorms under global warming

    Science.gov (United States)

    Singh, Martin S.; Kuang, Zhiming; Maloney, Eric D.; Hannah, Walter M.; Wolding, Brandon O.

    2017-10-01

    Intense thunderstorms produce rapid cloud updrafts and may be associated with a range of destructive weather events. An important ingredient in measures of the potential for intense thunderstorms is the convective available potential energy (CAPE). Climate models project increases in summertime mean CAPE in the tropics and subtropics in response to global warming, but the physical mechanisms responsible for such increases and the implications for future thunderstorm activity remain uncertain. Here, we show that high percentiles of the CAPE distribution (CAPE extremes) also increase robustly with warming across the tropics and subtropics in an ensemble of state-of-the-art climate models, implying strong increases in the frequency of occurrence of environments conducive to intense thunderstorms in future climate projections. The increase in CAPE extremes is consistent with a recently proposed theoretical model in which CAPE depends on the influence of convective entrainment on the tropospheric lapse rate, and we demonstrate the importance of this influence for simulated CAPE extremes using a climate model in which the convective entrainment rate is varied. We further show that the theoretical model is able to account for the climatological relationship between CAPE and a measure of lower-tropospheric humidity in simulations and in observations. Our results provide a physical basis on which to understand projected future increases in intense thunderstorm potential, and they suggest that an important mechanism that contributes to such increases may be present in Earth's atmosphere.

  6. Increasing potential for intense tropical and subtropical thunderstorms under global warming.

    Science.gov (United States)

    Singh, Martin S; Kuang, Zhiming; Maloney, Eric D; Hannah, Walter M; Wolding, Brandon O

    2017-10-31

    Intense thunderstorms produce rapid cloud updrafts and may be associated with a range of destructive weather events. An important ingredient in measures of the potential for intense thunderstorms is the convective available potential energy (CAPE). Climate models project increases in summertime mean CAPE in the tropics and subtropics in response to global warming, but the physical mechanisms responsible for such increases and the implications for future thunderstorm activity remain uncertain. Here, we show that high percentiles of the CAPE distribution (CAPE extremes) also increase robustly with warming across the tropics and subtropics in an ensemble of state-of-the-art climate models, implying strong increases in the frequency of occurrence of environments conducive to intense thunderstorms in future climate projections. The increase in CAPE extremes is consistent with a recently proposed theoretical model in which CAPE depends on the influence of convective entrainment on the tropospheric lapse rate, and we demonstrate the importance of this influence for simulated CAPE extremes using a climate model in which the convective entrainment rate is varied. We further show that the theoretical model is able to account for the climatological relationship between CAPE and a measure of lower-tropospheric humidity in simulations and in observations. Our results provide a physical basis on which to understand projected future increases in intense thunderstorm potential, and they suggest that an important mechanism that contributes to such increases may be present in Earth's atmosphere. Published under the PNAS license.

  7. Influence of electrolytes on growth, phototropism, nutation and surface potential in etiolated cucumber seedlings

    Science.gov (United States)

    Spalding, E. P.; Cosgrove, D. J.

    1993-01-01

    A variety of electrolytes (10-30 mol m-3) increased the relative growth rate of etiolated cucumber (Cucumis sativus L. cv. Burpee's Pickler) hypocotyls by 20-50% relative to water-only controls. The nonelectrolyte mannitol inhibited growth by 10%. All salts tested were effective, regardless of chemical composition or valence. Measurements of cell-sap osmolality ruled out an osmotic mechanism for the growth stimulation by electrolytes. This, and the nonspecificity of the response, indicate that an electrical property of the solutions was responsible for their growth-stimulating activity. Measurements of surface electrical potential supported this reasoning. Treatment with electrolytes also enhanced nutation and altered the pattern of phototropic curvature development. A novel analytical method for quantitating these effects on growth was developed. The evidence indicates that electrolytes influence an electrophysiological parameter that is involved in the control of cell expansion and the coordination of growth underlying tropisms and nutations.

  8. Streaming potential revisited: the influence of convection on the surface conductivity.

    Science.gov (United States)

    Saini, Rakesh; Garg, Abhinandan; Barz, Dominik P J

    2014-09-16

    Electrokinetic phenomena play an important role in the electrical characterization of surfaces. In terms of planar or porous substrates, streaming potential and/or streaming current measurements can be used to determine the zeta potential of the substrates in contact with aqueous electrolytes. In this work, we perform electrical impedance spectroscopy measurements to infer the electrical resistance in a microchannel with the same conditions as for a streaming potential experiment. Novel correlations are derived to relate the streaming current and streaming potential to the Reynolds number of the channel flow. Our results not only quantify the influence of surface conductivity, and here especially the contribution of the stagnant layer, but also reveal that channel resistance and therefore zeta potential are influenced by the flow in the case of low ionic strengths. We conclude that convection can have a significant impact on the electrical double layer configuration which is reflected by changes in the surfaces conductivity.

  9. Surface Complexation Modeling of Calcite Zeta Potential Measurement in Mixed Brines for Carbonate Wettability Characterization

    Science.gov (United States)

    Song, J.; Zeng, Y.; Biswal, S. L.; Hirasaki, G. J.

    2017-12-01

    We presents zeta potential measurements and surface complexation modeling (SCM) of synthetic calcite in various conditions. The systematic zeta potential measurement and the proposed SCM provide insight into the role of four potential determining cations (Mg2+, SO42- , Ca2+ and CO32-) and CO2 partial pressure in calcite surface charge formation and facilitate the revealing of calcite wettability alteration induced by brines with designed ionic composition ("smart water"). Brines with varying potential determining ions (PDI) concentration in two different CO2 partial pressure (PCO2) are investigated in experiments. Then, a double layer SCM is developed to model the zeta potential measurements. Moreover, we propose a definition for contribution of charged surface species and quantitatively analyze the variation of charged species contribution when changing brine composition. After showing our model can accurately predict calcite zeta potential in brines containing mixed PDIs, we apply it to predict zeta potential in ultra-low and pressurized CO2 environments for potential applications in carbonate enhanced oil recovery including miscible CO2 flooding and CO2 sequestration in carbonate reservoirs. Model prediction reveals that pure calcite surface will be positively charged in all investigated brines in pressurized CO2 environment (>1atm). Moreover, the sensitivity of calcite zeta potential to CO2 partial pressure in the various brine is found to be in the sequence of Na2CO3 > Na2SO4 > NaCl > MgCl2 > CaCl2 (Ionic strength=0.1M).

  10. Composites in small and simple devices to increase mixing on detector surfaces

    International Nuclear Information System (INIS)

    Hernandez, L F; Lima, R R; Leite, A R; Silva, M L P; Fachini, E R

    2013-01-01

    This work aims at three different applications for the betterment of plasma generated-composite thin films: pre-mixing, spray formation in miniaturized structures and an increase in the performance of detector surfaces. Miniaturized structures were projected, simulated with FEMLAB ® 3.2 software and then constructed. Clustered films made from tetraethoxysilane (TEOS) and nonafluoro(iso)butyl ether (HFE ® ) precursors were deposited on silicon, acrylic and quartz substrates for different kinds of film characterization/or in the projected structures. Physical and chemical characterization guided the selection of best films previous to/after UVC exposure. The active surfaces (plasma-deposited films) in structures were modified by UVC exposure and then tested. The applications include pre-mixing of liquids and/or spray formation, best results being obtained with surface covered by derivative-HFE films, which acted as passivation layers. Preliminary results show good humidity sensing for TEOS-derivative films.

  11. Increasing light coupling in a photovoltaic film by tuning nanoparticle shape with substrate surface energy

    Science.gov (United States)

    Kataria, Devika; Krishnamoorthy, Kothandam; Iyer, S. Sundar Kumar

    2017-08-01

    Tuning metal nanoparticle (MNP) contact angle on the surface it is formed can help maximise the useful optical coupling in photovoltaic films by localized surface plasmon (LSP) resonance—opening up the possibility of building improved photovoltaic cells. In this work experimental demonstration of optical absorption increase in copper phthalocyanine (CuPc) films by tuning silver MNP shape by changing its contact angles with substrate has been reported. Thin films of poly3,4 ethylenedioxythiophene: sodium dodecycl sulphate (PEDOT:SDS) with different surface energies were formed on indium tin oxide (ITO) coated glass by electro-deposition. Silver MNPs thermally evaporated directly on ozonised ITO as well as on the PEDOT:SDS films showed contact angles ranging from 60° to 125°. The CuPc layer was deposited on top of the MNPs. For the samples studied, best optical absorption in the CuPc layer was for a contact angle of 110°.

  12. Full-dimensional diabatic potential energy surfaces including dissociation: the ²E″ state of NO₃.

    Science.gov (United States)

    Eisfeld, Wolfgang; Vieuxmaire, Olivier; Viel, Alexandra

    2014-06-14

    A scheme to produce accurate full-dimensional coupled diabatic potential energy surfaces including dissociative regions and suitable for dynamical calculations is proposed. The scheme is successfully applied to model the two-sheeted surface of the (2)E″ state of the NO3 radical. An accurate potential energy surface for the NO₃⁻ anion ground state is developed as well. Both surfaces are based on high-level ab initio calculations. The model consists of a diabatic potential matrix, which is expanded to higher order in terms of symmetry polynomials of symmetry coordinates. The choice of coordinates is key for the accuracy of the obtained potential energy surfaces and is discussed in detail. A second central aspect is the generation of reference data to fit the expansion coefficients of the model for which a stochastic approach is proposed. A third ingredient is a new and simple scheme to handle problematic regions of the potential energy surfaces, resulting from the massive undersampling by the reference data unavoidable for high-dimensional problems. The final analytical diabatic surfaces are used to compute the lowest vibrational levels of NO₃⁻ and the photo-electron detachment spectrum of NO₃⁻ leading to the neutral radical in the (2)E″ state by full dimensional multi-surface wave-packet propagation for NO3 performed using the Multi-Configuration Time Dependent Hartree method. The achieved agreement of the simulations with available experimental data demonstrates the power of the proposed scheme and the high quality of the obtained potential energy surfaces.

  13. Surface self-potential patterns related to transmissive fracture trends during a water injection test

    Science.gov (United States)

    DesRoches, A. J.; Butler, K. E.; MacQuarrie, K. TB

    2018-03-01

    Variations in self-potential (SP) signals were recorded over an electrode array during a constant head injection test in a fractured bedrock aquifer. Water was injected into a 2.2 m interval isolated between two inflatable packers at 44 m depth in a vertical well. Negative SP responses were recorded on surface corresponding to the start of the injection period with strongest magnitudes recorded in electrodes nearest the well. SP response decreased in magnitude at electrodes further from the well. Deflation of the packer system resulted in a strong reversal in the SP signal. Anomalous SP patterns observed at surface at steady state were found to be aligned with dominant fracture strike orientations found within the test interval. Numerical modelling of fluid and current flow within a simplified fracture network showed that azimuthal patterns in SP are mainly controlled by transmissive fracture orientations. The strongest SP gradients occur parallel to hydraulic gradients associated with water flowing out of the transmissive fractures into the tighter matrix and other less permeable cross-cutting fractures. Sensitivity studies indicate that increasing fracture frequency near the well increases the SP magnitude and enhances the SP anomaly parallel to the transmissive set. Decreasing the length of the transmissive fractures leads to more fluid flow into the matrix and into cross-cutting fractures proximal to the well, resulting in a more circular and higher magnitude SP anomaly. Results from the field experiment and modelling provide evidence that surface-based SP monitoring during constant head injection tests has the ability to identify groundwater flow pathways within a fractured bedrock aquifer.

  14. The surface expression of HLA-F on decidual trophoblasts increases from mid to term gestation.

    Science.gov (United States)

    Shobu, Takanori; Sageshima, Noriko; Tokui, Hiroshi; Omura, Motoko; Saito, Keigo; Nagatsuka, Yuka; Nakanishi, Mari; Hayashi, Yukio; Hatake, Katsuhiko; Ishitani, Akiko

    2006-12-01

    HLA-F has recently only begun to be studied in earnest, and has been thought not to be expressed on the cell surface. However, in our previous report, we demonstrated surface expression of HLA-F on extravillous trophoblasts (EVTs) invading the decidua in term placental tissues. To better understand its function, we attempted to determine when surface expression of HLA-F begins during normal pregnancy, and whether there is a difference in expression between normal and preeclamptic placentas, by comparing the expression of HLA-G and -E by immunohistochemical staining with anti-HLA-E, -F and -G antibodies (3D12, 3D11 and 87G, respectively). In EVTs, HLA-F was expressed only in the cytoplasm weakly during the first trimester, after which expression increased and moved to the cell surface with the progression of pregnancy from the second trimester, which was confirmed by the results of double-labeled immunofluorescence staining with anti-HLA-F and anti-HLA-G antibodies, and by flow cytometry using trophoblasts isolated from the decidua. HLA-E showed similar expression as HLA-F, though it was expressed on the cell surface from the first trimester, while HLA-G was expressed strongly in the cytoplasm and on the cell surface during all stages of pregnancy. The expressions of HLA-E, -F and -G in preeclamptic placentas were not different from those in normal placentas, though there were a greater number of necrotic EVTs in preeclampsia. The increase in expression of HLA-E and HLA-F from the second trimester to full term was coincident with the timing of rapid growth of the fetus. Our results suggest that these may function together to prepare an environment that supports fetal growth.

  15. Increased Surface Roughness in Polydimethylsiloxane Films by Physical and Chemical Methods

    Directory of Open Access Journals (Sweden)

    Jorge Nicolás Cabrera

    2017-08-01

    Full Text Available Two methods, the first physical and the other chemical, were investigated to modify the surface roughness of polydimethylsiloxane (PDMS films. The physical method consisted of dispersing multi-walled carbon nanotubes (MWCNTs and magnetic cobalt ferrites (CoFe2O4 prior to thermal cross-linking, and curing the composite system in the presence of a uniform magnetic field H. The chemical method was based on exposing the films to bromine vapours and then UV-irradiating. The characterizing techniques included scanning electron microscopy (SEM, energy-dispersive spectroscopy (EDS, Fourier transform infrared (FTIR spectroscopy, optical microscopy, atomic force microscopy (AFM and magnetic force microscopy (MFM. The surface roughness was quantitatively analyzed by AFM. In the physical method, the random dispersion of MWCNTs (1% w/w and magnetic nanoparticles (2% w/w generated a roughness increase of about 200% (with respect to PDMS films without any treatment, but that change was 400% for films cured in the presence of H perpendicular to the surface. SEM, AFM and MFM showed that the magnetic particles always remained attached to the carbon nanotubes, and the effect on the roughness was interpreted as being due to a rupture of dispersion randomness and a possible induction of structuring in the direction of H. In the chemical method, the increase in roughness was even greater (1000%. Wells were generated with surface areas that were close to 100 μm2 and depths of up to 500 nm. The observations of AFM images and FTIR spectra were in agreement with the hypothesis of etching by Br radicals generated by UV on the polymer chains. Both methods induced important changes in the surface roughness (the chemical method generated the greatest changes due to the formation of surface wells, which are of great importance in superficial technological processes.

  16. Climbing exercise increases bone mass and trabecular bone turnover through transient regulation of marrow osteogenic and osteoclastogenic potentials in mice.

    Science.gov (United States)

    Mori, Toshiharu; Okimoto, Nobukazu; Sakai, Akinori; Okazaki, Yuichi; Nakura, Nariaki; Notomi, Takuya; Nakamura, Toshitaka

    2003-11-01

    To investigate the relationship between the effects of bone turnover and bone marrow cell development in bone cells, we developed a mouse voluntary climbing exercise model. Climbing exercise increased bone volume and transient osteogenic potential of bone marrow. This model would be suitable for investigating the mechanistic roles of mechanical loading. The relationship between bone mass gain and local bone formation and resorption in mechanically loaded bone is not well understood. Sixty-five C57BL/6J mice, 8 weeks of age, were assigned to five groups: a baseline control and two groups each of ground control and climbing exercise mice for 2 and 4 weeks. Mice were housed in a 100-cm tower and had to climb toward a bottle placed at the top to drink water. Compared with the ground control, bone mineral density of the left femur increased in the climbing mice at 4 weeks. At 2 and 4 weeks, bone formation rate (BFR/BS) of periosteal surface, the cross-sectional area, and moment of inertia were increased in the climbing mice, whereas BFR/BS and eroded surface (ES/BS) of endosteal surface did not differ. The trabecular bone volume (BV/TV) of the proximal tibia increased in climbing mice, and osteoclast surface (Oc.S/BS) and osteoclast number decreased at 2 weeks. At 4 weeks, there were increases in BV/TV and parameters of bone formation, including mineralized surface, mineral apposition rate, and bone formation rate. In marrow cell cultures from the tibia, the number of alkaline phosphatase+ colony forming units-fibroblastic and the area of mineralized nodule formation in climbing mice were increased, and the number of osteoclast-like TRACP+ multinucleated cells was lower at 2 weeks. At 4 weeks, these parameters recovered to the levels of the ground controls. Our results indicate that climbing increased trabecular bone volume and reduced bone resorption, with a subsequent increase in bone formation. Intermittent climbing downregulates marrow osteoclastogenic cells and

  17. Flavonoid-modified surfaces: multifunctional bioactive biomaterials with osteopromotive, anti-inflammatory, and anti-fibrotic potential.

    Science.gov (United States)

    Córdoba, Alba; Satué, María; Gómez-Florit, Manuel; Hierro-Oliva, Margarita; Petzold, Christiane; Lyngstadaas, Staale P; González-Martín, María Luisa; Monjo, Marta; Ramis, Joana M

    2015-03-11

    Flavonoids are small polyphenolic molecules of natural origin with antioxidant, anti-inflammatory, and antibacterial properties. Here, a bioactive surface based on the covalent immobilization of flavonoids taxifolin and quercitrin on titanium substrates is presented, using (3-aminopropyl)triethoxysilane (APTES) as coupling agent. FTIR and XPS measurements confirm the grafting of the flavonoids to the surfaces. Using 2-aminoethyl diphenylborinate (DPBA, a flavonoid-specific dye), the modified surfaces are imaged by fluorescence microscopy. The bioactivity of the flavonoid-modified surfaces is evaluated in vitro with human umbilical cord derived mesenchymal stem cells (hUC-MSCs) and human gingival fibroblasts (HGFs) and compared to that of simple flavonoid coatings prepared by drop casting. Flavonoid-modified surfaces show anti-inflammatory and anti-fibrotic potential on HGF. In addition, Ti surfaces covalently functionalized with flavonoids promote the differentiation of hUC-MSCs to osteoblasts--enhancing the expression of osteogenic markers, increasing alkaline phosphatase activity and calcium deposition; while drop-casted surfaces do not. These findings could have a high impact in the development of advanced implantable medical devices like bone implants. Given the broad range of bioactivities of flavonoid compounds, these surfaces are ready to be explored for other biomedical applications, e.g., as stent surface or tumor-targeted functionalized nanoparticles for cardiovascular or cancer therapies. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Efficient Geometry Minimization and Transition Structure Optimization Using Interpolated Potential Energy Surfaces and Iteratively Updated Hessians.

    Science.gov (United States)

    Zheng, Jingjing; Frisch, Michael J

    2017-12-12

    An efficient geometry optimization algorithm based on interpolated potential energy surfaces with iteratively updated Hessians is presented in this work. At each step of geometry optimization (including both minimization and transition structure search), an interpolated potential energy surface is properly constructed by using the previously calculated information (energies, gradients, and Hessians/updated Hessians), and Hessians of the two latest geometries are updated in an iterative manner. The optimized minimum or transition structure on the interpolated surface is used for the starting geometry of the next geometry optimization step. The cost of searching the minimum or transition structure on the interpolated surface and iteratively updating Hessians is usually negligible compared with most electronic structure single gradient calculations. These interpolated potential energy surfaces are often better representations of the true potential energy surface in a broader range than a local quadratic approximation that is usually used in most geometry optimization algorithms. Tests on a series of large and floppy molecules and transition structures both in gas phase and in solutions show that the new algorithm can significantly improve the optimization efficiency by using the iteratively updated Hessians and optimizations on interpolated surfaces.

  19. Vulnerability of United States Bridges to Potential Increases in Flooding from Climate Change

    Science.gov (United States)

    This study assesses the potential impacts of increased river flooding from climate change on bridges in the continental United States. Daily precipitation statistics from four climate models and three greenhouse gas (GHG) emissions scenarios (A2, A1B, and B1) are used to capture ...

  20. Increased transient receptor potential canonical type 3 channels in vasculature from hypertensive rats

    DEFF Research Database (Denmark)

    Liu, Daoyan; Yang, Dachun; He, Hongbo

    2009-01-01

    We tested the hypothesis that transient receptor potential canonical type 3 (TRPC3) channels are increased in vascular smooth muscle cells and aortic tissue from spontaneously hypertensive rats (SHR) compared with normotensive Wistar Kyoto rats. Expression of TRPC3 was analyzed by immunohistochem...

  1. The PyPES library of high quality semi-global potential energy surfaces.

    Science.gov (United States)

    Sibaev, Marat; Crittenden, Deborah L

    2015-11-05

    In this article, we present a Python-based library of high quality semi-global potential energy surfaces for 50 polyatomic molecules with up to six atoms. We anticipate that these surfaces will find widespread application in the testing of new potential energy surface construction algorithms and nuclear ro-vibrational structure theories. To this end, we provide the ability to generate the energy derivatives required for Taylor series expansions to sixth order about any point on the potential energy surface in a range of common coordinate systems, including curvilinear internal, Cartesian, and normal mode coordinates. The PyPES package, along with FORTRAN, C, MATLAB and Mathematica wrappers, is available at http://sourceforge.net/projects/pypes-lib. © 2015 Wiley Periodicals, Inc.

  2. Surface potential measurement of negative-ion-implanted insulators by analysing secondary electron energy distribution

    International Nuclear Information System (INIS)

    Toyota, Yoshitaka; Tsuji, Hiroshi; Nagumo, Syoji; Gotoh, Yasuhito; Ishikawa, Junzo; Sakai, Shigeki.

    1994-01-01

    The negative ion implantation method we have proposed is a noble technique which can reduce surface charging of isolated electrodes by a large margin. In this paper, the way to specify the surface potential of negative-ion-implanted insulators by the secondary electron energy analysis is described. The secondary electron energy distribution is obtained by a retarding field type energy analyzer. The result shows that the surface potential of fused quartz by negative-ion implantation (C - with the energy of 10 keV to 40 keV) is negatively charged by only several volts. This surface potential is extremely low compared with that by positive-ion implantation. Therefore, the negative-ion implantation is a very effective method for charge-up free implantation without charge compensation. (author)

  3. Increasing Extracted Beam Current Density in Ion Thrusters through Plasma Potential Modification

    Science.gov (United States)

    Arthur, Neil; Foster, John

    2015-09-01

    A gridded ion thruster's maximum extractable beam current is determined by the space charge limit. The classical formulation does not take into account finite ion drift into the acceleration gap. It can be shown that extractable beam current can be increased beyond the conventional Child-Langmuir law if the ions enter the gap at a finite drift speed. In this work, ion drift in a 10 cm thruster is varied by adjusting the plasma potential relative to the potential at the extraction plane. Internal plasma potential variations are achieved using a novel approach involving biasing the magnetic cusps. Ion flow variations are assessed using simulated beam extraction in conjunction with a retarding potential analyzer. Ion beam current density changes at a given total beam voltage in full beam extraction tests are characterized as a function of induced ion drift velocity as well.

  4. Biofilm formation by Listeria monocytogenes on stainless steel surface and biotransfer potential

    Directory of Open Access Journals (Sweden)

    Maíra Maciel Mattos de Oliveira

    2010-03-01

    Full Text Available An experimental model was proposed to study biofilm formation by Listeria monocytogenes ATCC 19117 on AISI 304 (#4 stainless steel surface and biotransfer potential during this process. In this model, biofilm formation was conducted on the surface of stainless steel coupons, set on a stainless steel base with 4 divisions, each one supporting 21 coupons. Trypic Soy Broth was used as bacterial growth substrate, with incubation at 37 ºC and stirring of 50 rpm. The number of adhered cells was determined after 3, 48, 96, 144, 192 and 240 hours of biofilm formation and biotransfer potential from 96 hours. Stainless steel coupons were submitted to Scanning Electron Microscopy (SEM after 3, 144 and 240 hours. Based on the number of adhered cells and SEM, it was observed that L. monocytogenes adhered rapidly to the stainless steel surface, with mature biofilm being formed after 240 hours. The biotransfer potential of bacterium to substrate occurred at all the stages analyzed. The rapid capacity of adhesion to surface, combined with biotransfer potential throughout the biofilm formation stages, make L. monocytogenes a potential risk to the food industry. Both the experimental model developed and the methodology used were efficient in the study of biofilm formation by L. monocytogenes on stainless steel surface and biotransfer potential.

  5. Disordered electrical potential observed on the surface of SiO2 by electric field microscopy

    International Nuclear Information System (INIS)

    GarcIa, N; Yan Zang; Ballestar, A; Barzola-Quiquia, J; Bern, F; Esquinazi, P

    2010-01-01

    The electrical potential on the surface of ∼300 nm thick SiO 2 grown on single-crystalline Si substrates has been characterized at ambient conditions using electric field microscopy. Our results show an inhomogeneous potential distribution with fluctuations up to ∼0.4 V within regions of 1 μm. The potential fluctuations observed at the surface of these usual dielectric holders of graphene sheets should induce strong variations in the graphene charge densities and provide a simple explanation for some of the anomalous behaviors of the transport properties of graphene.

  6. TMS-induced cortical potentiation during wakefulness locally increases slow wave activity during sleep.

    Directory of Open Access Journals (Sweden)

    Reto Huber

    2007-03-01

    Full Text Available Sleep slow wave activity (SWA is thought to reflect sleep need, increasing in proportion to the length of prior wakefulness and decreasing during sleep. However, the process responsible for SWA regulation is not known. We showed recently that SWA increases locally after a learning task involving a circumscribed brain region, suggesting that SWA may reflect plastic changes triggered by learning.To test this hypothesis directly, we used transcranial magnetic stimulation (TMS in conjunction with high-density EEG in humans. We show that 5-Hz TMS applied to motor cortex induces a localized potentiation of TMS-evoked cortical EEG responses. We then show that, in the sleep episode following 5-Hz TMS, SWA increases markedly (+39.1+/-17.4%, p<0.01, n = 10. Electrode coregistration with magnetic resonance images localized the increase in SWA to the same premotor site as the maximum TMS-induced potentiation during wakefulness. Moreover, the magnitude of potentiation during wakefulness predicts the local increase in SWA during sleep.These results provide direct evidence for a link between plastic changes and the local regulation of sleep need.

  7. Infrared spectroscopy of the Ar-C2HD complex: Potential energy surfaces

    International Nuclear Information System (INIS)

    Bemish, R.J.; Miller, R.E.

    1996-01-01

    The argon-acetylene complex has been studied by a number of experimental and theoretical groups, with the aim in mind of determining an accurate potential energy surface for this system. Both microwave and infrared spectroscopy have provided detailed rotational and vibrational constants for this system. In addition, scattering experiments have been reported and ab initio calculation performed. Even with all of this, there are still some fundamental questions that remain unanswered with regards to the shape of the potential surface. The authors will review some of this work to outline the current situation. In the present study, the authors have obtained high resolution infrared spectra of the Ar-C 2 HD complex with the aim of providing additional molecular constants that could be used to help constrain the potential. Collocation calculations are reported, using a number of potential surfaces, for this and the normal isotopomer. This additional data helps to answer some of these open questions

  8. Non-additivity of molecule-surface van der Waals potentials from force measurements

    Science.gov (United States)

    Wagner, Christian; Fournier, Norman; Ruiz, Victor G.; Li, Chen; Müllen, Klaus; Rohlfing, Michael; Tkatchenko, Alexandre; Temirov, Ruslan; Tautz, F. Stefan

    2014-11-01

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive potential between differently sized organic molecules and a metal surface using an atomic force microscope. Our choice of molecules and the large molecule-surface separation cause this attraction to be purely of vdW type. The experiment allows testing the asymptotic vdW force law and its validity range. We find a superlinear growth of the vdW attraction with molecular size, originating from the increased deconfinement of electrons in the molecules. Because such non-additive vdW contributions are not accounted for in most first-principles or empirical calculations, we suggest further development in that direction.

  9. Non-additivity of molecule-surface van der Waals potentials from force measurements.

    Science.gov (United States)

    Wagner, Christian; Fournier, Norman; Ruiz, Victor G; Li, Chen; Müllen, Klaus; Rohlfing, Michael; Tkatchenko, Alexandre; Temirov, Ruslan; Tautz, F Stefan

    2014-11-26

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive potential between differently sized organic molecules and a metal surface using an atomic force microscope. Our choice of molecules and the large molecule-surface separation cause this attraction to be purely of vdW type. The experiment allows testing the asymptotic vdW force law and its validity range. We find a superlinear growth of the vdW attraction with molecular size, originating from the increased deconfinement of electrons in the molecules. Because such non-additive vdW contributions are not accounted for in most first-principles or empirical calculations, we suggest further development in that direction.

  10. Increased critical current and improved magnetic field response of BSCCO material by surface diffusion of silver

    International Nuclear Information System (INIS)

    Negm, Y.Z.; Zimmerman, G.O.; Powers, R.E.; Eckhardt, K.A.

    1994-01-01

    The authors have developed a procedure of increasing the critical current of BSCCO ceramic superconducting material, the value of the critical current is increased by 30%. Moreover the degradation of the critical current with the applied magnetic field had been decreased. The procedure consists of applying a thin layer of silver to the surface of the conductor. The details of the procedure and the improved performance are discussed. This procedure has great significance for any future application of HTSC materials where high current carrying capacity is necessary. It will therefore be important in the application of HTSC materials to SSC high current leads

  11. Increase of surface solar irradiance across East China related to changes in aerosol properties during the past decade

    Science.gov (United States)

    Li, Jing; Jiang, Yiwei; Xia, Xiangao; Hu, Yongyun

    2018-03-01

    Previously, it was widely documented that an overall decrease in surface solar radiation occurred in China at least until 2005, in contrast to the general background of ‘global brightening’. Increased anthropogenic aerosol emissions were speculated to be the source of the reduction. In this study, we extend the trend analysis to the most recent decade from 2005-2015 and find that surface solar radiation has shifted from ‘dimming’ to ‘brightening’ over East China, with the largest increase over the northeast and southeast parts. Meanwhile, satellite and ground observation both indicate a reduction in aerosol optical depth (AOD) during the same period, whereas no significant trends in cloud amount show up. Detailed analysis using co-located radiation and aerosol observation at the XiangHe station in North China suggests that both AOD and single scattering albedo (SSA) changes contribute to the radiation trends. AOD reduction contributes to the increase of direct solar radiation, also decreasing the diffuse radiation, while the increase of SSA serves to increase the diffuse fraction. Simple calculations using a radiative transfer model confirm that the two effects combined explain changes in the global solar radiation and its components effectively. Our results have implications for potential climate effects with the reduction of China’s aerosol emissions, and the necessity to monitor aerosol composition in addition to its loading.

  12. Development of titanium alloys and surface treatments to increase the implants lifetime

    Directory of Open Access Journals (Sweden)

    Joan Lario-Femenía

    2016-12-01

    Full Text Available The population aging together with increase of life expectancy forces the development of new prosthesis which may present a higher useful life. The clinical success of implants is based on the osseointegration achievement. Therefore, metal implants must have a mechanical compatibility with the substituted bone, which is achieved through a combination of low elastic modulus, high flexural and fatigue strength. The improvement, in the short and long term, of the osseointegration depends on several factors, where the macroscopic design and dimensional, material and implant surface topography are of great importance. This article is focused on summarizing the advantages that present the titanium and its alloys to be used as biomaterials, and the development that they have suffered in recent decades to improve their biocompatibility. Consequently, the implants evolution has been recapitulated and summarized through three generations. In the recent years the interest on the surface treatments for metallic prostheses has been increased, the main objective is achieve a lasting integration between implant and bone tissue, in the shortest time possible. On this article various surface treatments currently used to modify the surface roughness or to obtain coatings are described it; it is worthy to mention the electrochemical oxidation with post-heat treated to modify the titanium oxide crystalline structure. After the literature review conducted for prepare this article, the ? titanium alloys, with a nanotubes surface of obtained by electrochemical oxidation and a subsequent step of heat treatment to obtain a crystalline structure are the future option to improve long term biocompatibility of titanium prostheses.

  13. Long- term manure exposure increases soil bacterial community potential for plasmid uptake

    DEFF Research Database (Denmark)

    Musovic, Sanin; Klümper, Uli; Dechesne, Arnaud

    2014-01-01

    Microbial communities derived from soils subject to different agronomic treatments were challenged with three broad host range plasmids, RP4, pIPO2tet and pRO101, via solid surface filter matings to assess their permissiveness. Approximately 1 in 10 000 soil bacterial cells could receive and main......Microbial communities derived from soils subject to different agronomic treatments were challenged with three broad host range plasmids, RP4, pIPO2tet and pRO101, via solid surface filter matings to assess their permissiveness. Approximately 1 in 10 000 soil bacterial cells could receive...... and maintain the plasmids. The community permissiveness increased up to 100% in communities derived from manured soil. While the plasmid transfer frequency was significantly influenced by both the type of plasmid and the agronomic treatment, the diversity of the transconjugal pools was purely plasmid dependent...

  14. Linear and Nonlinear Hydrological Cycle Responses to Increasing Sea Surface Temperature

    Science.gov (United States)

    Toda, Masaki; Watanabe, Masahiro

    2018-02-01

    An effective mechanism for determining tropical rainfall patterns in response to sea surface temperature (SST) increases with varying magnitude and horizontal distribution has not been developed thus far in climate change studies. In order to examine changes in precipitation pattern with increasing SST, we conducted a series of atmospheric general circulation model experiments using a 30 year record of observed SST for which either globally uniform SST increases of 1 K, 2 K, and 4 K or El Niño/La Niña-like patterned SST anomaly has been imposed. Although the global-mean precipitation linearly increases with the SST increase irrespective of its spatial distribution, regional precipitation changes were found to occur nonlinearly depending on the magnitude of the uniform SST increase. Owing to nonlinearity in the atmospheric circulation response, the regional hydrological sensitivity was larger with a smaller increase in SST. The precipitation response to the SST pattern was, however, quasi-linear to the magnitude of the SST change and can be separated from the response to the uniform SST increase. This study thus emphasizes the importance of relative amplitudes of uniform and structured SST increases for future rainfall projection.

  15. Potentiation increases peak twitch torque by enhancing rates of torque development and relaxation.

    Science.gov (United States)

    Froyd, Christian; Beltrami, Fernando Gabe; Jensen, Jørgen; Noakes, Timothy David

    2013-01-01

    The aim of this study was to measure the extent to which potentiation changes in response to an isometric maximal voluntary contraction. Eleven physically active subjects participated in two separate studies. Single stimulus of electrical stimulation of the femoral nerve was used to measure torque at rest in unpotentiated quadriceps muscles (study 1 and 2), and potentiated quadriceps muscles torque in a 10 min period after a 5 s isometric maximal voluntary contraction of the quadriceps muscles (study 1). Additionally, potentiated quadriceps muscles torque was measured every min after a further 10 maximal voluntary contractions repeated every min (study 2). Electrical stimulation repeated several times without previous maximal voluntary contraction showed similar peak twitch torque. Peak twitch torque 4 s after a 5 s maximal voluntary contraction increased by 45±13% (study 1) and by 56±10% (study 2), the rate of torque development by 53±13% and 82±29%, and the rate of relaxation by 50±17% and 59±22%, respectively, but potentiation was lost already two min after a 5 s maximal voluntary contraction. There was a tendency for peak twitch torque to increase for the first five repeated maximal voluntary contractions, suggesting increased potentiation with additional maximal voluntary contractions. Correlations for peak twitch torque vs the rate of torque development and for the rate of relaxation were r(2)= 0.94 and r(2)=0.97. The correlation between peak twitch torque, the rate of torque development and the rate of relaxation suggests that potentiation is due to instantaneous changes in skeletal muscle contractility and relaxation.

  16. How do features of dressage arenas influence training surface properties which are potentially associated with lameness?

    Science.gov (United States)

    Murray, Rachel C; Walters, Juli; Snart, Hannah; Dyson, Sue; Parkin, Tim

    2010-11-01

    Results from a previous study indicated that there are specific arena surface characteristics that are associated with an increased likelihood of lameness in dressage horses. It is important to understand what modifiable arena factors lead to these detrimental surface characteristics. The aim of this study was to describe the use of training surfaces and arenas for United Kingdom dressage horses and to investigate any relationships between arena/surface variables and detrimental surface characteristics. Data from a questionnaire returned by 22.5% of all 11,363 registered members of British Dressage were used for the study. Univariate and multivariable logistic regression models were developed with each of the previously identified surface characteristics as dependent variables. Respondents reported that the majority of arenas were privately owned, sized 20 × 40 m and had a sand and rubber surface. The results indicated that wax-coated and sand and rubber surfaces were associated with less detrimental surface properties than sand, sand and PVC, woodchips or grass. Woodchips were most strongly associated with the detrimental characteristic of slipping, and sand with tripping. The findings indicated that any arena surface should have a base, with limestone the recommended surface, and that crushed concrete was best avoided. This information supported previous studies in racehorses that indicated that surface maintenance is essential, especially when many horses are using an arena daily. Problems were less likely if an arena was privately owned. Copyright © 2010. Published by Elsevier Ltd.

  17. Electrocardiogram: his bundle potentials can be recorded noninvasively beat by beat on surface electrocardiogram.

    Science.gov (United States)

    Wang, Gaopin; Liu, Renguang; Chang, Qinghua; Xu, Zhaolong; Zhang, Yingjie; Pan, Dianzhu

    2017-03-15

    The micro waveform of His bundle potential can't be recorded beat-to-beat on surface electrocardiogram yet. We have found that the micro-wavelets before QRS complex may be related to atrioventricular conduction system potentials. This study is to explore the possibility of His bundle potential can be noninvasively recorded on surface electrocardiogram. We randomized 65 patients undergoing radiofrequency catheter ablation of paroxysmal superventricular tachycardia (exclude overt Wolff-Parkinson-White syndrome) to receive "conventional electrocardiogram" and "new electrocardiogram" before the procedure. His bundle electrogram was collected during the procedure. Comparative analysis of PA s (PA interval recorded on surface electrocardiogram), AH s (AH interval recorded on surface electrocardiogram) and HV s (HV interval recorded on surface electrocardiogram) interval recorded on surface "new electrocardiogram" and PA, AH, HV interval recorded on His bundle electrogram was investigated. There was no difference (P > 0.05) between groups in HV s interval (49.63 ± 6.19 ms) and HV interval (49.35 ± 6.49 ms). Results of correlational analysis found that HV S interval was significantly positively associated with HV interval (r = 0.929; P electrocardiogram. Noninvasive His bundle potential tracing might represent a new method for locating the site of atrioventricular block and identifying the origin of a wide QRS complex.

  18. Potentiating the antibacterial effect of silver nanospheres by surface-capping with chlorhexidine gluconate

    Science.gov (United States)

    Priyadarshini, Balasankar Meera; Fawzy, Amr S.

    2017-04-01

    In this work, the commercial polyvinylpyrrolidone (PVP)-capped silver nanospheres (Ag-NSP) were surface decorated with chlorhexidine gluconate (CHXg) for potentiating the antibacterial properties of Ag-NSP. Different formulations of CHXg-loaded Ag-NSP (Ag-NSP/CHXg) were prepared by varying the incubation times (0.5, 1.5, and 3 h). A thorough characterization of Ag-NSP/CHXg nanospheres has been carried out by dynamic light scattering (DLS), transmission electron microscopy (TEM), energy-dispersive surface elemental composition spectral analysis (SEM/EDX), Fourier transform infrared spectroscopy (FTIR), percentage (%) CHXg loading efficiency (LE), in vitro CHXg and Ag+ ion release, antibacterial/biofilm inhibition assay, and human mesenchymal stem cells (hMSCs) cytotoxicity evaluation. DLS measured nanospheres to be fashion showing maximum release of 74.83 ± 20.67% from Ag-NSP/CHXg-3h at 14 days. A slow release of Ag+ ions was detected; however, the surface decoration of Ag-NSP substantially hampered/restricted the liberation of ions. Agar well diffusion, MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium), and crystal violet assay suggested good antibacterial/antibiofilm activity of Ag-NSP/CHXg that correlated with the increasing %LE of nanospheres. hMSCs cytotoxicity study showed low toxicity properties of all nanosphere formulations, except for Ag-NSP/CHXg-3h, affecting the cell viability at all proposed concentrations and exposure time points. CHXg accentuated the antibacterial properties of Ag-NSP.

  19. Beyond Massive MIMO: The Potential of Positioning With Large Intelligent Surfaces

    Science.gov (United States)

    Hu, Sha; Rusek, Fredrik; Edfors, Ove

    2018-04-01

    We consider the potential for positioning with a system where antenna arrays are deployed as a large intelligent surface (LIS), which is a newly proposed concept beyond massive-MIMO where future man-made structures are electronically active with integrated electronics and wireless communication making the entire environment \\lq\\lq{}intelligent\\rq\\rq{}. In a first step, we derive Fisher-information and Cram\\'{e}r-Rao lower bounds (CRLBs) in closed-form for positioning a terminal located perpendicular to the center of the LIS, whose location we refer to as being on the central perpendicular line (CPL) of the LIS. For a terminal that is not on the CPL, closed-form expressions of the Fisher-information and CRLB seem out of reach, and we alternatively find approximations of them which are shown to be accurate. Under mild conditions, we show that the CRLB for all three Cartesian dimensions ($x$, $y$ and $z$) decreases quadratically in the surface-area of the LIS, except for a terminal exactly on the CPL where the CRLB for the $z$-dimension (distance from the LIS) decreases linearly in the same. In a second step, we analyze the CRLB for positioning when there is an unknown phase $\\varphi$ presented in the analog circuits of the LIS. We then show that the CRLBs are dramatically increased for all three dimensions but decrease in the third-order of the surface-area. Moreover, with an infinitely large LIS the CRLB for the $z$-dimension with an unknown $\\varphi$ is 6 dB higher than the case without phase uncertainty, and the CRLB for estimating $\\varphi$ converges to a constant that is independent of the wavelength $\\lambda$. At last, we extensively discuss the impact of centralized and distributed deployments of LIS, and show that a distributed deployment of LIS can enlarge the coverage for terminal-positioning and improve the overall positioning performance.

  20. The Effect of Images on Surface Potential and Resistance Calculation of Grounding Systems

    Directory of Open Access Journals (Sweden)

    MARTINS, A.

    2015-05-01

    Full Text Available In the grounding systems with a two layers soil, the calculation of the surface potential using the image method is sometimes impossible due to singularities, avoiding researchers to use the method for electrodes in the bottom layer. In the literature this problem solution is refereed as unreliable or solved with other more complex methods. This paper presents a new approach to calculate the surface potentials in a two. layer soil, for electrodes in the bottom layer, when images are at surface. The singularities in computing surface voltage, when the first image upwards lies at surface, are analysed and it's shown that a small change in top layer thickness allows an approximate solution. Surface potentials due to grid conductor are also considered and the values of resistance are compared with those from other methodologies. Singularities for a ground rod that crosses the two layers are also treated. The obtained values of resistance are not satisfactory, due to lower segments images that overlap the upper segments. This paper also proposes shifting the surface of the upper part of the ground rod, in the upper layer, or taking the modulus of the mutual resistance, to overcome this difficulty.

  1. Adaptive microbial population shifts in response to a continuous ethanol blend release increases biodegradation potential

    International Nuclear Information System (INIS)

    Ma, Jie; Nossa, Carlos W.; Xiu, Zongming; Rixey, William G.; Alvarez, Pedro J.J.

    2013-01-01

    The fate of fuel releases largely depends on the poorly-understood response in microbial community structure and function. Here, we evaluate the impacts to the microbial community resulting from a pilot-scale continuous release (10 months) of a 10% v:v ethanol solution mixed with benzene and toluene (50 mg/L each). Microbial population shifts were characterized by pyrosequencing-based 16S rRNA analysis and by quantitative PCR targeting Bacteria, Archaea, and functional genes for methanogenesis (mcrA), acetogenesis (fhs) and aerobic degradation of aromatic hydrocarbons (PHE), which could occur in hypoxic micro-environments. The release stimulated microbial growth, increased species richness and diversity, and selected for genotypes involved in fermentative degradation (the relative abundance of mcrA and fhs increased 18- and 6-fold, respectively). The growth of putative hydrocarbon degraders and commensal anaerobes, and increases in microbial diversity and in degradation rates suggest an adaptive response that increases the potential for natural attenuation of ethanol blend releases. -- Highlights: •Pyrosequencing discerned microbial community changes after an ethanol blend release. •Adaptive microbial population shifts that enhance bioremediation were observed. •Hydrocarbon degraders and fermentation syntrophs proliferated. •Surprisingly, both species richness and taxonomic diversity increased. -- Pyrosequencing analysis discerned adaptive microbial population shifts that increase natural attenuation potential of an ethanol-blended fuel release

  2. Comparison of Degrees of Potential-Energy-Surface Anharmonicity for Complexes and Clusters with Hydrogen Bonds

    Science.gov (United States)

    Kozlovskaya, E. N.; Doroshenko, I. Yu.; Pogorelov, V. E.; Vaskivskyi, Ye. V.; Pitsevich, G. A.

    2018-01-01

    Previously calculated multidimensional potential-energy surfaces of the MeOH monomer and dimer, water dimer, malonaldehyde, formic acid dimer, free pyridine-N-oxide/trichloroacetic acid complex, and protonated water dimer were analyzed. The corresponding harmonic potential-energy surfaces near the global minima were constructed for series of clusters and complexes with hydrogen bonds of different strengths based on the behavior of the calculated multidimensional potential-energy surfaces. This enabled the introduction of an obvious anharmonicity parameter for the calculated potential-energy surfaces. The anharmonicity parameter was analyzed as functions of the size of the analyzed area near the energy minimum, the number of points over which energies were compared, and the dimensionality of the solved vibrational problem. Anharmonicity parameters for potential-energy surfaces in complexes with strong, medium, and weak H-bonds were calculated under identical conditions. The obtained anharmonicity parameters were compared with the corresponding diagonal anharmonicity constants for stretching vibrations of the bridging protons and the lengths of the hydrogen bridges.

  3. Mycorrhiza Symbiosis Increases the Surface for Sunlight Capture in Medicago truncatula for Better Photosynthetic Production

    Science.gov (United States)

    Adolfsson, Lisa; Keresztes, Áron; Uddling, Johan; Schoefs, Benoît; Spetea, Cornelia

    2015-01-01

    Arbuscular mycorrhizal (AM) fungi play a prominent role in plant nutrition by supplying mineral nutrients, particularly inorganic phosphate (Pi), and also constitute an important carbon sink. AM stimulates plant growth and development, but the underlying mechanisms are not well understood. In this study, Medicago truncatula plants were grown with Rhizophagus irregularis BEG141 inoculum (AM), mock inoculum (control) or with Pi fertilization. We hypothesized that AM stimulates plant growth through either modifications of leaf anatomy or photosynthetic activity per leaf area. We investigated whether these effects are shared with Pi fertilization, and also assessed the relationship between levels of AM colonization and these effects. We found that increased Pi supply by either mycorrhization or fertilization led to improved shoot growth associated with increased nitrogen uptake and carbon assimilation. Both mycorrhized and Pi-fertilized plants had more and longer branches with larger and thicker leaves than the control plants, resulting in an increased photosynthetically active area. AM-specific effects were earlier appearance of the first growth axes and increased number of chloroplasts per cell section, since they were not induced by Pi fertilization. Photosynthetic activity per leaf area remained the same regardless of type of treatment. In conclusion, the increase in growth of mycorrhized and Pi-fertilized Medicago truncatula plants is linked to an increase in the surface for sunlight capture, hence increasing their photosynthetic production, rather than to an increase in the photosynthetic activity per leaf area. PMID:25615871

  4. Mycorrhiza symbiosis increases the surface for sunlight capture in Medicago truncatula for better photosynthetic production.

    Directory of Open Access Journals (Sweden)

    Lisa Adolfsson

    Full Text Available Arbuscular mycorrhizal (AM fungi play a prominent role in plant nutrition by supplying mineral nutrients, particularly inorganic phosphate (Pi, and also constitute an important carbon sink. AM stimulates plant growth and development, but the underlying mechanisms are not well understood. In this study, Medicago truncatula plants were grown with Rhizophagus irregularis BEG141 inoculum (AM, mock inoculum (control or with P(i fertilization. We hypothesized that AM stimulates plant growth through either modifications of leaf anatomy or photosynthetic activity per leaf area. We investigated whether these effects are shared with P(i fertilization, and also assessed the relationship between levels of AM colonization and these effects. We found that increased P(i supply by either mycorrhization or fertilization led to improved shoot growth associated with increased nitrogen uptake and carbon assimilation. Both mycorrhized and P(i-fertilized plants had more and longer branches with larger and thicker leaves than the control plants, resulting in an increased photosynthetically active area. AM-specific effects were earlier appearance of the first growth axes and increased number of chloroplasts per cell section, since they were not induced by P(i fertilization. Photosynthetic activity per leaf area remained the same regardless of type of treatment. In conclusion, the increase in growth of mycorrhized and P(i-fertilized Medicago truncatula plants is linked to an increase in the surface for sunlight capture, hence increasing their photosynthetic production, rather than to an increase in the photosynthetic activity per leaf area.

  5. Influence of Surface Charge/Potential of a Gold Electrode on the Adsorptive/Desorptive Behaviour of Fibrinogen

    International Nuclear Information System (INIS)

    Dargahi, Mahdi; Konkov, Evgeny; Omanovic, Sasha

    2015-01-01

    Highlights: • Adsorptive/desorptive behavior of fibrinogen (FG) on an electrochemically-polarized gold substrate is reported. • The adsorption affinity of FG (afFG) is constant on a negatively-charged substrate surface. • The afFG increases linearly with an increase in positive substrate surface charge. • The FG adsorption kinetics is strongly dependant on substrate surface charge. • The adsorbed FG layer can be desorbed by electrochemical evolution of hydrogen and oxygen. - Abstract: The effect of gold substrate surface charge (potential) on adsorptive/desorptive behaviour of fibrinogen (FG) was studied by employing differential capacitance (DC) and polarization modulated infrared reflection absorption spectroscopy (PM-IRRAS), in terms of FG adsorption thermodynamics, kinetics, and desorption kinetics. The gold substrate surface charge was modulated in-situ within the electrochemical double-layer region by means of electrochemical potentiostatic polarization in a FG-containing electrolyte, thus avoiding the interference of other physico-chemical properties of the gold surface on FG’s interfacial behaviour. The FG adsorption equilibrium was modeled using the Langmuir isotherm. Highly negative values of apparent Gibbs free energy of adsorption (ranging from from −52.1 ± 0.4 to −55.8 ± 0.8 kJ mol −1 , depending on the FG adsorption potential) indicated a highly spontaneous and strong adsorption of FG onto the gold surface. The apparent Gibbs free energy of adsorption was found to be independent of surface charge when the surface was negatively charged. However, when the gold surface was positively charged, the apparent Gibbs free energy of adsorption exhibited a pronounced linear relationship with the surface charge, shifting to more negative values with an increase in positive electrode potential. The adsorption kinetics of FG was also found to be dependent on gold surface charge in a similar manner to the apparent Gibbs free energy of adsorption

  6. Potential-induced structural transitions of DL-homocysteine monolayers on Au(111) electrode surfaces

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Demetriou, Anna; Welinder, Anne Christina

    2005-01-01

    Monolayers of homocysteine on Au(111)-surfaces have been investigated by voltammetry, in situ scanning tunnelling microscopy (STM) and subtractively normalised interfacial Fourier transform spectroscopy (SNIFTIRS). A pair of sharp voltammetric peaks build up in the potential range 0 to -0.1 V (vs....... SCE) in phosphate buffer pH 7.7. The peak half-widths are about 25 mV at a scan rate of 10 mV s(-1). This is much smaller than for a one-electron Faradaic process (90.6 mV) under similar conditions. The coverage of homocysteine is 6.1 (+/- 0.2) x 10(-10) Mol cm(-2), or 5.9 x 10(-5) C cm(-2), from Au...... and lower pH. The midpoint potential shows biphasic behaviour, decreasing linearly with increasing pH until pH 10.4 towards a constant value at higher pH. The cathodic and anodic peak charges decay at pH both higher and lower than 7.7. The homocysteine monolayer was investigated by in situ STM at different...

  7. Improved Model for Increased Surface Recombination Current in Irradiated Bipolar Junction Transistors

    Science.gov (United States)

    Barnaby, H. J.; Vermeire, B.; Campola, M. J.

    2015-08-01

    Current gain degradation in irradiated bipolar junction transistors is primarily due to excess base current caused by enhanced carrier recombination in the emitter-base space-charge region (SCR). Radiation-induced traps at the interface between silicon and the bipolar base oxide facilitate the recombination process primarily above the sensitive emitter-base junction. This leads to an increase in surface recombination current in the SCR, which is a non-ideal component of the BJT's base current characteristic under active bias conditions. In this paper, we derive a precise analytical model for surface recombination current that captures bias dependencies typically omitted from traditional models. This improved model is validated by comparisons to these traditional approaches.

  8. Multidecadal Scale Detection Time for Potentially Increasing Atlantic Storm Surges in a Warming Climate

    Science.gov (United States)

    Lee, Benjamin Seiyon; Haran, Murali; Keller, Klaus

    2017-10-01

    Storm surges are key drivers of coastal flooding, which generate considerable risks. Strategies to manage these risks can hinge on the ability to (i) project the return periods of extreme storm surges and (ii) detect potential changes in their statistical properties. There are several lines of evidence linking rising global average temperatures and increasingly frequent extreme storm surges. This conclusion is, however, subject to considerable structural uncertainty. This leads to two main questions: What are projections under various plausible statistical models? How long would it take to distinguish among these plausible statistical models? We address these questions by analyzing observed and simulated storm surge data. We find that (1) there is a positive correlation between global mean temperature rise and increasing frequencies of extreme storm surges; (2) there is considerable uncertainty underlying the strength of this relationship; and (3) if the frequency of storm surges is increasing, this increase can be detected within a multidecadal timescale (≈20 years from now).

  9. Smoking and increased Alzheimer’s disease risk: A review of potential mechanisms

    Science.gov (United States)

    Durazzo, Timothy C.; Mattsson, Niklas; Weiner, Michael W.

    2014-01-01

    Background Cigarette smoking has been linked with both increased and decreased risk for Alzheimer’s disease (AD). This is relevant for the US military because the prevalence of smoking in the military is approximately 11% higher than in civilians. Methods Systematic review of published studies on the association between smoking and increased risk for AD, and preclinical and human literature on the relationships between smoking, nicotine exposure and AD-related neuropathology. Original data from comparisons of smoking and never-smoking cognitively normal elders on in vivo amyloid imaging are also presented. Results Overall, the literature indicates that former/active smoking is related to a significantly increased risk for AD. Cigarette smoke/smoking is associated with AD neuropathology in preclinical models and humans. Smoking-related cerebral oxidative stress is a potential mechanism promoting AD pathophysiology and increased risk for AD. Conclusions A reduction in the incidence of smoking will likely reduce the future prevalence of AD. PMID:24924665

  10. Self-consistent density functional calculation of the image potential at a metal surface

    Energy Technology Data Exchange (ETDEWEB)

    Jung, J [Departamento de Fisica Fundamental, Universidad Nacional de Educacion a Distancia, Apartado 60141, 28080 Madrid (Spain); Alvarellos, J E [Departamento de Fisica Fundamental, Universidad Nacional de Educacion a Distancia, Apartado 60141, 28080 Madrid (Spain); Chacon, E [Instituto de Ciencias de Materiales de Madrid, Consejo Superior de Investigaciones CientIficas, E-28049 Madrid (Spain); GarcIa-Gonzalez, P [Departamento de Fisica Fundamental, Universidad Nacional de Educacion a Distancia, Apartado 60141, 28080 Madrid (Spain)

    2007-07-04

    It is well known that the exchange-correlation (XC) potential at a metal surface has an image-like asymptotic behaviour given by -1/4(z-z{sub 0}), where z is the coordinate perpendicular to the surface. Using a suitable fully non-local functional prescription, we evaluate self-consistently the XC potential with the correct image behaviour for simple jellium surfaces in the range of metallic densities. This allows a proper comparison between the corresponding image-plane position, z{sub 0}, and other related quantities such as the centroid of an induced charge by an external perturbation. As a by-product, we assess the routinely used local density approximation when evaluating electron density profiles, work functions, and surface energies by focusing on the XC effects included in the fully non-local description.

  11. Self-consistent density functional calculation of the image potential at a metal surface

    International Nuclear Information System (INIS)

    Jung, J; Alvarellos, J E; Chacon, E; GarcIa-Gonzalez, P

    2007-01-01

    It is well known that the exchange-correlation (XC) potential at a metal surface has an image-like asymptotic behaviour given by -1/4(z-z 0 ), where z is the coordinate perpendicular to the surface. Using a suitable fully non-local functional prescription, we evaluate self-consistently the XC potential with the correct image behaviour for simple jellium surfaces in the range of metallic densities. This allows a proper comparison between the corresponding image-plane position, z 0 , and other related quantities such as the centroid of an induced charge by an external perturbation. As a by-product, we assess the routinely used local density approximation when evaluating electron density profiles, work functions, and surface energies by focusing on the XC effects included in the fully non-local description

  12. Irrigation Induced Surface Cooling in the Context of Modern and Increased Greenhouse Gas Forcing

    Science.gov (United States)

    Cook, Benjamin I.; Puma, Michael J.; Krakauer, Nir Y.

    2010-01-01

    There is evidence that expected warming trends from increased greenhouse gas (GHG) forcing have been locally masked by irrigation induced cooling, and it is uncertain how the magnitude of this irrigation masking effect will change in the future. Using an irrigation dataset integrated into a global general circulation model, we investigate the equilibrium magnitude of irrigation induced cooling under modern (Year 2000) and increased (A1B Scenario, Year 2050) GHG forcing, using modern irrigation rates in both scenarios. For the modern scenario, the cooling is largest over North America, India, the Middle East, and East Asia. Under increased GHG forcing, this cooling effect largely disappears over North America, remains relatively unchanged over India, and intensifies over parts of China and the Middle East. For North America, irrigation significantly increases precipitation under modern GHG forcing; this precipitation enhancement largely disappears under A1B forcing, reducing total latent heat fluxes and the overall irrigation cooling effect. Over India, irrigation rates are high enough to keep pace with increased evaporative demand from the increased GHG forcing and the magnitude of the cooling is maintained. Over China, GHG forcing reduces precipitation and shifts the region to a drier evaporative regime, leading to a relatively increased impact of additional water from irrigation on the surface energy balance. Irrigation enhances precipitation in the Middle East under increased GHG forcing, increasing total latent heat fluxes and enhancing the irrigation cooling effect. Ultimately, the extent to which irrigation will continue to compensate for the warming from increased GHG forcing will primarily depend on changes in the background evaporative regime, secondary irrigation effects (e.g. clouds, precipitation), and the ability of societies to maintain (or increase) current irrigation rates.

  13. Acidic pH increases airway surface liquid viscosity in cystic fibrosis

    Science.gov (United States)

    Tang, Xiao Xiao; Ostedgaard, Lynda S.; Hoegger, Mark J.; Moninger, Thomas O.; Karp, Philip H.; McMenimen, James D.; Choudhury, Biswa; Varki, Ajit; Stoltz, David A.; Welsh, Michael J.

    2016-01-01

    Cystic fibrosis (CF) disrupts respiratory host defenses, allowing bacterial infection, inflammation, and mucus accumulation to progressively destroy the lungs. Our previous studies revealed that mucus with abnormal behavior impaired mucociliary transport in newborn CF piglets prior to the onset of secondary manifestations. To further investigate mucus abnormalities, here we studied airway surface liquid (ASL) collected from newborn piglets and ASL on cultured airway epithelia. Fluorescence recovery after photobleaching revealed that the viscosity of CF ASL was increased relative to that of non-CF ASL. CF ASL had a reduced pH, which was necessary and sufficient for genotype-dependent viscosity differences. The increased viscosity of CF ASL was not explained by pH-independent changes in HCO3– concentration, altered glycosylation, additional pH-induced disulfide bond formation, increased percentage of nonvolatile material, or increased sulfation. Treating acidic ASL with hypertonic saline or heparin largely reversed the increased viscosity, suggesting that acidic pH influences mucin electrostatic interactions. These findings link loss of cystic fibrosis transmembrane conductance regulator–dependent alkalinization to abnormal CF ASL. In addition, we found that increasing Ca2+ concentrations elevated ASL viscosity, in part, independently of pH. The results suggest that increasing pH, reducing Ca2+ concentration, and/or altering electrostatic interactions in ASL might benefit early CF. PMID:26808501

  14. MRD-CI potential surfaces using balanced basis sets. IV. The H2 molecule and the H3 surface

    International Nuclear Information System (INIS)

    Wright, J.S.; Kruus, E.

    1986-01-01

    The utility of midbond functions in molecular calculations was tested in two cases where the correct results are known: the H 2 potential curve and the collinear H 3 potential surface. For H 2 , a variety of basis sets both with and without bond functions was compared to the exact nonrelativistic potential curve of Kolos and Wolniewicz [J. Chem. Phys. 43, 2429 (1965)]. It was found that optimally balanced basis sets at two levels of quality were the double zeta single polarization plus sp bond function basis (BF1) and the triple zeta double polarization plus two sets of sp bond function basis (BF2). These gave bond dissociation energies D/sub e/ = 4.7341 and 4.7368 eV, respectively (expt. 4.7477 eV). Four basis sets were tested for basis set superposition errors, which were found to be small relative to basis set incompleteness and therefore did not affect any conclusions regarding basis set balance. Basis sets BF1 and BF2 were used to construct potential surfaces for collinear H 3 , along with the corresponding basis sets DZ*P and TZ*PP which contain no bond functions. Barrier heights of 12.52, 10.37, 10.06, and 9.96 kcal/mol were obtained for basis sets DZ*P, TZ*PP, BF1, and BF2, respectively, compared to an estimated limiting value of 9.60 kcal/mol. Difference maps, force constants, and relative rms deviations show that the bond functions improve the surface shape as well as the barrier height

  15. Exploring the Potential for Increased Production from the Wave Energy Converter Lifesaver by Reactive Control

    Directory of Open Access Journals (Sweden)

    Marta Molinas

    2013-07-01

    Full Text Available Fred Olsen is currently testing their latest wave energy converter (WEC, Lifesaver, outside of Falmouth Bay in England, preparing it for commercial operation at the Wavehub test site. Previous studies, mostly focusing on hydrodynamics and peak to average power reduction, have shown that this device has potential for increased power extraction using reactive control. This article extends those analyses, adding a detailed model of the all-electric power take-off (PTO system, consisting of a permanent magnet synchronous generator, inverter and DC-link. Time domain simulations are performed to evaluate the PTO capabilities of the modeled WEC. However, when tuned towards reactive control, the generator losses become large, giving a very low overall system efficiency. Optimal control with respect to electrical output power is found to occur with low added mass, and when compared to pure passive loading, a 1% increase in annual energy production is estimated. The main factor reducing the effect of reactive control is found to be the minimum load-force constraint of the device. These results suggest that the Lifesaver has limited potential for increased production by reactive control. This analysis is nevertheless valuable, as it demonstrates how a wave-to-wire model can be used for investigation of PTO potential, annual energy production estimations and evaluations of different control techniques for a given WEC device.

  16. Improved method for producing catalytic carbon and the potential for increasing its use in commercial applications

    Science.gov (United States)

    Kruse, C.W.; Lizzio, A.A.; DeBarr, J.A.; Feizoulof, C.A.

    1997-01-01

    This paper describes an improved method for producing a catalytic carbon, which was first produced in the late 1960s. The new activated carbon (AC) removes and destroys organic pollutants in aqueous solutions. To determine the effects of altering the pore structure and surface chemistry of activated carbons, carbons differing in the amount of functional groups on their surfaces were prepared in three steps: (1) oxidizing AC with boiling nitric acid, (2) washing oxidized AC with water to remove the acid, and (3) heating oxidized AC to temperatures beteween 100 and 925 ??C. The surfaces of the products were characterized by determining the amount of CO2 and CO evolved during temperature-programmed desorption. Depending on the desorption temperature, these modified carbons showed enhanced adsorptive and/or catalytic properties that included (1) carbon molecular sieves for separating oxygen from nitrogen, (2) increased capacity for adsorbing sulfur dioxide, (3) stronger adsorption of p-nitrophenol from water, and (4) catalysis of dehydrochlorination reactions. A dehydrohalogenation catalyst produced by the oxidation/ desorption steps was found to be similar to one prepared in the 1960s by oxidizing AC with air at 500-700 ??C. The dehydrohalogenation catalyst produced by either the old method or the new method involves an oxidized surface that has been exposed to a 500-700 ??C temperature range. This carbon catalyst retains modified adsorptive properties of the AC from which it is produced. It can be used both to adsorb pollutants from liquid or gaseous streams and to convert them to recyclable products.

  17. Permutation invariant potential energy surfaces for polyatomic reactions using atomistic neural networks

    International Nuclear Information System (INIS)

    Kolb, Brian; Zhao, Bin; Guo, Hua; Li, Jun; Jiang, Bin

    2016-01-01

    The applicability and accuracy of the Behler-Parrinello atomistic neural network method for fitting reactive potential energy surfaces is critically examined in three systems, H + H 2 → H 2 + H, H + H 2 O → H 2 + OH, and H + CH 4 → H 2 + CH 3 . A pragmatic Monte Carlo method is proposed to make efficient choice of the atom-centered mapping functions. The accuracy of the potential energy surfaces is not only tested by fitting errors but also validated by direct comparison in dynamically important regions and by quantum scattering calculations. Our results suggest this method is both accurate and efficient in representing multidimensional potential energy surfaces even when dissociation continua are involved.

  18. Conduction abnormalities in the right ventricular outflow tract in Brugada syndrome detected body surface potential mapping.

    Science.gov (United States)

    Guillem, Maria S; Climent, Andreu M; Millet, Jose; Berne, Paola; Ramos, Rafael; Brugada, Josep; Brugada, Ramon

    2010-01-01

    Brugada syndrome (BrS) causes sudden death in patients with structurally normal hearts. Manifestation of BrS in the ECG is dynamical and most patients do not show unequivocal signs of the syndrome during ECG screening. We have obtained 67-lead body surface potential mapping recordings of 25 patients with BrS and analyzed their spatial distribution of surface potentials during ventricular activation. Six patients presented spontaneous type I ECGs during the recording. These patients showed non-dipolarities in isopotential maps at the right ventricular outflow tract (RVOT) region during the development of terminal R waves in right precordial leads. Same finding was observed in 95% of BrS patients not presenting a type I ECG. Conduction delay in the RVOT may be a consistent finding in BrS patients that can be identified by Body Surface Potential Mapping.

  19. Electric Field and Potential Distributions along Surface of Silicone Rubber Polymer Insulators Using Finite Element Method

    OpenAIRE

    B. Marungsri; W. Onchantuek; A. Oonsivilai

    2008-01-01

    This paper presents the simulation the results of electric field and potential distributions along surface of silicone rubber polymer insulators. Near the same leakage distance subjected to 15 kV in 50 cycle salt fog ageing test, alternate sheds silicone rubber polymer insulator showed better contamination performance than straight sheds silicone rubber polymer insulator. Severe surface ageing was observed on the straight sheds insulator. The objective of this work is to ...

  20. Potentialities inherent in high-energy surface treatment for corrosion protection of metals

    International Nuclear Information System (INIS)

    Kolotyrkin, V.I.; Knyazheva, V.M.

    1991-01-01

    Natural resources of alloying elements are limited. Application of protective coatings, surface alloying, modification of its structure make up one of the most important problems, successful solution of which will permit a sharp reduction of metal consumption, increase in the quality and service time of equipment and machines, increase in output per man - hour. Four high-energy methods of anticorrosion treatment of metal surface: gas-plasma, detonation, laser and electron-beam ones, are assessed in the review

  1. Conformational Explosion: Understanding the Complexity of the Para-Dialkylbenzene Potential Energy Surfaces

    Science.gov (United States)

    Mishra, Piyush; Hewett, Daniel M.; Zwier, Timothy S.

    2017-06-01

    This talk focuses on the single-conformation spectroscopy of small-chain para-dialkylbenzenes. This work builds on previous studies from our group on long-chain n-alkylbenzenes that identified the first folded structure in octylbenzene. The dialkylbenzenes are representative of a class of molecules that are common components of coal and aviation fuel and are known to be present in vehicle exhaust. We bring the molecules para-diethylbenzene, para-dipropylbenzene and para-dibutylbenzene into the gas phase and cool the molecules in a supersonic expansion. The jet-cooled molecules are then interrogated using laser-induced fluorescence excitation, fluorescence dip IR spectroscopy (FDIRS) and dispersed fluorescence. The LIF spectra in the S_{0}-S_{1} origin region show dramatic increases in the number of resolved transitions with increasing length of alkyl chains, reflecting an explosion in the number of unique low-energy conformations formed when two independent alkyl chains are present. Since the barriers to isomerization of the alkyl chain are similar in size, this results in an 'egg carton' shape to the potential energy surface. We use a combination of electronic frequency shift and alkyl CH stretch infrared spectra to generate a consistent set of conformational assignments.

  2. Single-ion and pair-interaction potentials near simple metal surfaces

    International Nuclear Information System (INIS)

    Barnett, R.N.; Barrera, R.G.; Cleveland, C.L.; Landman, U.

    1983-01-01

    Presented is a model for semi-infinite simple metals which does not require crystalline order or a single species, and thus is applicable to problems of defect energetics near the surface and random-alloy surfaces as well as ideal metal surfaces. The formulation is based on the use of ionic pseudopotentials and linear-response theory. An expression for the total energy is obtained which depends explicitly on ionic species and position. This expression is decomposed into a density-dependent term and single-ion and ionic pair-interaction potential terms. The single-ion potentials oscillate about a constant bulk value, with the magnitude of the oscillation decreasing rapidly away from the surface. The interaction between pairs of ions near the surface is shown to be a noncentral force interaction which differs significantly from the central-force bulk pair potential. The effect of quantum interference in the response of the semi-infinite electron gas to the ions is seen in both the single-ion and the pair-interaction potentials. Results are presented for the simple metals sodium, potassium, and rubidium

  3. A many-body embedded atom potential for describing ejection of atoms from surfaces

    International Nuclear Information System (INIS)

    Garrison, B.J.; Walzl, K.; El-Maazawi, M.; Winograd, N.; Reimann, C.T.; Deaven, D.M.

    1989-01-01

    In this paper, we show that many-body interactions are important for describing the energy- and angle-resolved distributions of neutral Rh atoms ejected from keV-ion-bombarded Rh{111}. We compare separate classical-dynamics simulations of the sputtering process assuming either a many-body potential or a pairwise additive potential. The most dramatic difference between the many-body potential and the pair potential is the predicted kinetic energy distributions. The pair-potential kinetic energy distribution peaks at ∼ 2 eV, whereas the many-body potential predicts a broader peak at ∼ 4 eV, giving much better agreement with experiment. This difference between the model potentials is due to the predicted nature of the attractive interaction in the surface region through which all ejecting particles pass. (author)

  4. Activation of Transient Receptor Potential Vanilloid 4 Increases NMDA-Activated Current in Hippocampal Pyramidal Neurons.

    Science.gov (United States)

    Li, Lin; Qu, Weijun; Zhou, Libin; Lu, Zihong; Jie, Pinghui; Chen, Lei; Chen, Ling

    2013-01-01

    The glutamate excitotoxicity, mediated through N-methyl-d-aspartate receptors (NMDARs), plays an important role in cerebral ischemia injury. Transient receptor potential vanilloid 4 (TRPV4) can be activated by multiple stimuli that may happen during stroke. The present study evaluated the effect of TRPV4 activation on NMDA-activated current (INMDA) and that of blocking TRPV4 on brain injury after focal cerebral ischemia in mice. We herein report that activation of TRPV4 by 4α-PDD and hypotonic stimulation increased INMDA in hippocampal CA1 pyramidal neurons, which was sensitive to TRPV4 antagonist 10 μ M/2 μ 1/mouse [DOSAGE ERROR CORRECTED] and NMDAR antagonist AP-5, indicating that TRPV4 activation potentiates NMDAR response. In addition, the increase in INMDA by hypotonicity was sensitive to the antagonist of NMDAR NR2B subunit, but not of NR2A subunit. Furthermore, antagonists of calcium/calmodulin-dependent protein kinase II (CaMKII) significantly attenuated hypotonicity-induced increase in INMDA, while antagonists of protein kinase C or casein kinase II had no such effect, indicating that phosphorylation of NR2B subunit by CaMKII is responsible for TRPV4-potentiated NMDAR response. Finally, we found that intracerebroventricular injection of 10 μ m/2 μ 1/mouse [DOSAGE ERROR CORRECTED] after 60 min middle cerebral artery occlusion reduced the cerebral infarction with at least a 12 h efficacious time-window. These findings indicate that activation of TRPV4 increases NMDAR function, which may facilitate glutamate excitotoxicity. Closing TRPV4 may exert potent neuroprotection against cerebral ischemia injury through many mechanisms at least including the prevention of NMDAR-mediated glutamate excitotoxicity.

  5. Synchronization modulation increases transepithelial potentials in MDCK monolayers through Na/K pumps.

    Directory of Open Access Journals (Sweden)

    Vu Tran

    Full Text Available Transepithelial potential (TEP is the voltage across a polarized epithelium. In epithelia that have active transport functions, the force for transmembrane flux of an ion is dictated by the electrochemical gradient in which TEP plays an essential role. In epithelial injury, disruption of the epithelial barrier collapses the TEP at the wound edge, resulting in the establishment of an endogenous wound electric field (∼100 mV/mm that is directed towards the center of the wound. This endogenous electric field is implicated to enhance wound healing by guiding cell migration. We thus seek techniques to enhance the TEP, which may increase the wound electric fields and enhance wound healing. We report a novel technique, termed synchronization modulation (SM using a train of electric pulses to synchronize the Na/K pump activity, and then modulating the pumping cycles to increase the efficiency of the Na/K pumps. Kidney epithelial monolayers (MDCK cells maintain a stable TEP and transepithelial resistance (TER. SM significantly increased TEP over four fold. Either ouabain or digoxin, which block Na/K pump, abolished SM-induced TEP increases. In addition to the pump activity, basolateral distribution of Na/K pumps is essential for an increase in TEP. Our study for the first time developed an electrical approach to significantly increase the TEP. This technique targeting the Na/K pump may be used to modulate TEP, and may have implication in wound healing and in diseases where TEP needs to be modulated.

  6. Foraging on the potential energy surface: a swarm intelligence-based optimizer for molecular geometry.

    Science.gov (United States)

    Wehmeyer, Christoph; Falk von Rudorff, Guido; Wolf, Sebastian; Kabbe, Gabriel; Schärf, Daniel; Kühne, Thomas D; Sebastiani, Daniel

    2012-11-21

    We present a stochastic, swarm intelligence-based optimization algorithm for the prediction of global minima on potential energy surfaces of molecular cluster structures. Our optimization approach is a modification of the artificial bee colony (ABC) algorithm which is inspired by the foraging behavior of honey bees. We apply our modified ABC algorithm to the problem of global geometry optimization of molecular cluster structures and show its performance for clusters with 2-57 particles and different interatomic interaction potentials.

  7. Lithium inclusion in indium metal-organic frameworks showing increased surface area and hydrogen adsorption

    Directory of Open Access Journals (Sweden)

    Mathieu Bosch

    2014-12-01

    Full Text Available Investigation of counterion exchange in two anionic In-Metal-Organic Frameworks (In-MOFs showed that partial replacement of disordered ammonium cations was achieved through the pre-synthetic addition of LiOH to the reaction mixture. This resulted in a surface area increase of over 1600% in {Li [In(1,3 − BDC2]}n and enhancement of the H2 uptake of approximately 275% at 80 000 Pa at 77 K. This method resulted in frameworks with permanent lithium content after repeated solvent exchange as confirmed by inductively coupled plasma mass spectrometry. Lithium counterion replacement appears to increase porosity after activation through replacement of bulkier, softer counterions and demonstrates tuning of pore size and properties in MOFs.

  8. Toward accurate prediction of potential energy surfaces and the spectral density of hydrogen bonded systems

    International Nuclear Information System (INIS)

    Rekik, Najeh

    2014-01-01

    Despite the considerable progress made in quantum theory and computational methods, detailed descriptions of the potential energy surfaces of hydrogen-bonded systems have not yet been achieved. In addition, the hydrogen bond (H-bond) itself is still so poorly understood at the fundamental level that it remains unclear exactly what geometry constitutes a “real” H-bond. Therefore, in order to investigate features essential for hydrogen bonded complexes, a simple, efficient, and general method for calculating matrix elements of vibrational operators capable of describing the stretching modes and the H-bond bridges of hydrogen-bonded systems is proposed. The derived matrix elements are simple and computationally easy to evaluate, which makes the method suitable for vibrational studies of multiple-well potentials. The method is illustrated by obtaining potential energy surfaces for a number of two-dimensional systems with repulsive potentials chosen to be in Gaussian form for the stretching mode and of the Morse-type for the H-bond bridge dynamics. The forms of potential energy surfaces of weak and strong hydrogen bonds are analyzed by varying the asymmetry of the Gaussian potential. Moreover, the choice and applicability of the selected potential for the stretching mode and comparison with other potentials used in the area of hydrogen bond research are discussed. The approach for the determination of spectral density has been constructed in the framework of the linear response theory for which spectral density is obtained by Fourier transform of the autocorrelation function of the dipole moment operator of the fast mode. The approach involves anharmonic coupling between the high frequency stretching vibration (double well potential) and low-frequency donor-acceptor stretching mode (Morse potential) as well as the electrical anharmonicity of the dipole moment operator of the fast mode. A direct relaxation mechanism is incorporated through a time decaying exponential

  9. Zooplankton responses to increasing sea surface temperatures in the southeastern Australia global marine hotspot

    Science.gov (United States)

    Kelly, Paige; Clementson, Lesley; Davies, Claire; Corney, Stuart; Swadling, Kerrie

    2016-10-01

    Southeastern Australia is a 'hotspot' for oceanographic change. Here, rapidly increasing sea surface temperatures, rising at more than double the global trend, are largely associated with a southerly extension of the East Australian Current (EAC) and its eddy field. Maria Island, situated at the southern end of the EAC extension at 42°S, 148°E, has been used as a site to study temperature-driven biological trends in this region of accelerated change. Zooplankton have short life cycles (usually Australia are responding to increased temperatures through relocation, long-term increases in warm-water species and a shift towards a zooplankton community dominated by small copepods. The biological trends present evidence of extended EAC influence at Maria Island into autumn and winter months, which has allowed for the rapid establishment of warm-water species during these seasons, and has increased the similarity between Maria Island and the more northerly Port Hacking zooplankton community. Generalised Linear Models (GLM) suggest the high salinity and low nutrient properties of EAC-water to be the primary drivers of increasing abundances of warm-water species off southeastern Australia. Changes in both the species composition and size distribution of the Maria Island zooplankton community will have effects for pelagic fisheries. This study provides an indication of how zooplankton communities influenced by intensifying Western Boundary currents may respond to rapid environmental change.

  10. Large projected increases in rain-on-snow flood potential over western North America

    Science.gov (United States)

    Musselman, K. N.; Ikeda, K.; Barlage, M. J.; Lehner, F.; Liu, C.; Newman, A. J.; Prein, A. F.; Mizukami, N.; Gutmann, E. D.; Clark, M. P.; Rasmussen, R.

    2017-12-01

    In the western US and Canada, some of the largest annual flood events occur when warm storm systems drop substantial rainfall on extensive snow-cover. For example, last winter's Oroville dam crisis in California was exacerbated by rapid snowmelt during a rain-on-snow (ROS) event. We present an analysis of ROS events with flood-generating potential over western North America simulated at high-resolution by the Weather Research and Forecasting (WRF) model run for both a 13-year control time period and re-run with a `business-as-usual' future (2071-2100) climate scenario. Daily ROS with flood-generating potential is defined as rainfall of at least 10 mm per day falling on snowpack of at least 10 mm water equivalent, where the sum of rainfall and snowmelt contains at least 20% snowmelt. In a warmer climate, ROS is less frequent in regions where it is historically common, and more frequent elsewhere. This is evidenced by large simulated reductions in snow-cover and ROS frequency at lower elevations, particularly in warmer, coastal regions, and greater ROS frequency at middle elevations and in inland regions. The same trend is reflected in the annual-average ROS runoff volume (rainfall + snowmelt) aggregated to major watersheds; large reductions of 25-75% are projected for much of the U.S. Pacific Northwest, while large increases are simulated for the Colorado River basin, western Canada, and the higher elevations of the Sierra Nevada. In the warmer climate, snowmelt contributes substantially less to ROS runoff per unit rainfall, particularly in inland regions. The reduction in snowmelt contribution is due to a shift in ROS timing from warm spring events to cooler winter conditions and/or from warm, lower elevations to cool, higher elevations. However, the slower snowmelt is offset by an increase in rainfall intensity, maintaining the flood potential of ROS at or above historical levels. In fact, we report large projected increases in the intensity of extreme ROS events

  11. Estimating Potential Increased Bladder Cancer Risk Due to Increased Bromide Concentrations in Sources of Disinfected Drinking Waters - slides

    Science.gov (United States)

    Public water systems are increasingly facing higher bromide levels in their source waters from anthropogenic contamination through coal-fired powerplants, conventional oil and gas extraction, and hydraulic fracturing. Climate change is likely to exacerbate this in coming years. W...

  12. Estimating Potential Increased Bladder Cancer Risk Due to Increased Bromide Concentrations in Sources of Disinfected Drinking Waters

    Science.gov (United States)

    Public water systems are increasingly facing higher bromide levels in their source waters from anthropogenic contamination through coal-fired power plants, conventional oil and gas extraction, and hydraulic fracturing. Climate change is likely to exacerbate this in coming years. ...

  13. Potential determinants of deductible uptake in health insurance: How to increase uptake in The Netherlands?

    Science.gov (United States)

    van Winssen, K P M; van Kleef, R C; van de Ven, W P M M

    2016-12-01

    In health insurance, voluntary deductibles are offered to the insured in return for a premium rebate. Previous research has shown that 11 % of the Dutch insured opted for a voluntary deductible (VD) in health insurance in 2014, while the highest VD level was financially profitable for almost 50 % of the population in retrospect. To explain this discrepancy, this paper identifies and discusses six potential determinants of the decision to opt for a VD from the behavioral economic literature: loss aversion, risk attitude, ambiguity aversion, debt aversion, omission bias, and liquidity constraints. Based on these determinants, five potential strategies are proposed to increase the number of insured opting for a VD. Presenting the VD as the default option and providing transparent information regarding the VD are the two most promising strategies. If, as a result of these strategies, more insured would opt for a VD, moral hazard would be reduced.

  14. Artemisinins, new miconazole potentiators resulting in increased activity against Candida albicans biofilms.

    Science.gov (United States)

    De Cremer, Kaat; Lanckacker, Ellen; Cools, Tanne L; Bax, Marijke; De Brucker, Katrijn; Cos, Paul; Cammue, Bruno P A; Thevissen, Karin

    2015-01-01

    Mucosal biofilm-related fungal infections are very common, and the incidence of recurrent oral and vulvovaginal candidiasis is significant. As resistance to azoles (the preferred treatment) is occurring, we aimed at identifying compounds that increase the activity of miconazole against Candida albicans biofilms. We screened 1,600 compounds of a drug-repositioning library in combination with a subinhibitory concentration of miconazole. Synergy between the best identified potentiators and miconazole was characterized by checkerboard analyses and fractional inhibitory concentration indices. Hexachlorophene, pyrvinium pamoate, and artesunate act synergistically with miconazole in affecting C. albicans biofilms. Synergy was most pronounced for artesunate and structural homologues thereof. No synergistic effect could be observed between artesunate and fluconazole, caspofungin, or amphotericin B. Our data reveal enhancement of the antibiofilm activity of miconazole by artesunate, pointing to potential combination therapy consisting of miconazole and artesunate to treat C. albicans biofilm-related infections. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  15. POSSIBILITIES TO INCREASE THE LEVERAGE THE TOURISM POTENTIAL IN HISTORICAL REGIONS CRISANA

    Directory of Open Access Journals (Sweden)

    BARBU IONEL

    2014-12-01

    Full Text Available In this work we aimed to identify some possibilities of increasing the recovery of the tourism potential of the historical region Crisan. Given the multitude of economic implications, socio-cultural and environmental impacts of rural tourism by increasing recovery tourist potential, the positive impact of this economic activity will be felt by all concerned: residents, entrepreneurs, tourists and local public administration. We analyzed a set of the 26 factors were analyzed, ranking obtained from processing the responses provided by the 391 respondents. Based on this ranking, based on the average score obtained, calculated by coding the answers of respondents, we could say that all factors have an average score above the average of 3 points, contributed in a more visible to development of rural tourism from historical region Crisana. Any intervention or any project that aims to increase the influence of one or more of these factors can bring economic impacts, socio-cultural or ecological more important. On the contrary, all factors had a mean score less than 3 points can be considered difficulties for the development of this economic activity, and any projects developed that have targeted these factors, not have attained to the extent expected.

  16. Potential and Kinetic Electron Emissions from HOPG Surface Irradiated by Highly Charged Xenon and Neon Ions

    International Nuclear Information System (INIS)

    Yu-Yu, Wang; Yong-Tao, Zhao; Jian-Rong, Sun; De-Hui, Li; Jin-Yu, Li; Ping-Zhi, Wang; Guo-Qing, Xiao; Abdul, Qayyum

    2011-01-01

    Highly charged 129 Xe q+ (q = 10−30) and 40 Ne q+ (q = 4−8) ion-induced secondary electron emissions on the surface of highly oriented pyrolytic graphite (HOPG) are reported. The total secondary electron yield is measured as a function of the potential energy of incident ions. The experimental data are used to separate contributions of kinetic and potential electron yields. Our results show that about 4.5% and 13.2% of ion's potential energies are consumed in potential electron emission due to different Xe q+ -HOPG and Ne q+ -HOPG combinations. A simple formula is introduced to estimate the fraction of ion's potential energy for potential electron emission. (atomic and molecular physics)

  17. Increased acellular and cellular surface mineralization induced by nanogrooves in combination with a calcium-phosphate coating.

    Science.gov (United States)

    Klymov, Alexey; Song, Jiankang; Cai, Xinjie; Te Riet, Joost; Leeuwenburgh, Sander; Jansen, John A; Walboomers, X Frank

    2016-02-01

    The current work evaluated the influence of nanoscale surface-topographies in combination with a calcium phosphate (CaP) coating on acellular and cellular surface mineralization. Four groups of substrates were produced, including smooth, grooved (940nm pitch, 430nm groove width, 185nm depth), smooth coated, and grooved coated. The substrates were characterized by scanning/transmission electron microscopy and atomic force microscopy. Osteoblast-like MC3T3 cells were cultured on the substrates for a period up to 35days under osteogenic conditions. Differentiation was observed by alkaline phosphatase assay and PCR of collagen I (COLI), osteopontin (OPN), osteocalcin (OC), bone-morphogenic protein 2 (BMP2), and bone sialoprotein (BSP). Mineralization was quantified by a calcium assay and Alizarin Red staining. In addition, acellular mineralization was determined after incubation of substrates in just cell culture medium without cells. Results showed that a reproducible nano-metric (∼50nm) CaP-layer could be applied on the substrates, without losing the integrity of the topographical features. While no relevant differences were found for cell viability, cells on smooth surfaces proliferated for a longer period than cells on grooved substrates. In addition, differentiation was affected by topographies, as indicated by an increased expression of OC, OPN and ALP activity. Deposition of a CaP coating significantly increased the acellular mineralization of smooth as well grooved substrate-surfaces. However, this mineralizing effect was strongly reduced in the presence of cells. In the cell seeded situation, mineralization was significantly increased by the substrate topography, while only a minor additive effect of the coating was observed. In conclusion, the model presented herein can be exploited for experimental evaluation of cell-surface interaction processes and optimization of bone-anchoring capability of implants. The model showed that substrates modified with Ca

  18. Study of surface potential contamination in radioisotope and radiopharmaceutical production facilities and alternative solutions

    International Nuclear Information System (INIS)

    Suhaedi Muhammad; Rimin Sumantri; Farida Tusafariah; Djarwanti Rahayu Pipin Soedjarwo

    2013-01-01

    Radioisotope and radiopharmaceutical production facilities that exist in their operations around the world in the form of radiological impacts of radiation exposure, contamination of surface and air contamination. Given the number of existing open source in radioisotope and radiopharmaceutical production facility, then the possibility of surface contamination in the work area is quite high. For that to protect the safety and health of both workers, the public and the environment, then the licensee must conduct an inventory of some of the potential that could result in contamination of surfaces in radioisotope and radiopharmaceutical production facilities. Several potential to cause surface contamination in radioisotope and radiopharmaceutical production facilities consist of loss of resources, the VAC system disorders, impaired production facilities, limited resources and lack of work discipline and radioactive waste handling activities. From the study of some potential, there are several alternative solutions that can be implemented by the licensee to address the contamination of the surface so as not to cause adverse radiological impacts for both radiation workers, the public or the environment. (author)

  19. Electrostatic potential of mean force between two curved surfaces in the presence of counterion connectivity

    Science.gov (United States)

    Zhou, Shiqi

    2015-11-01

    In this paper, we investigate effects of counterion connectivity (i.e., association of the counterions into a chain molecule) on the electrostatic potential of mean force (EPMF) between two similarly charged cylinder rods in a primitive model electrolyte solution by solving a classical density functional theory. The main findings include the following: (i) The counterion connectivity helps in inducing a like-charge-attractionlike (LCA-like) phenomenology even in a monovalent counterion solution wherein the LCA-like observation generally does not occur without the counterion connectivity. (ii) For divalent counterion solutions, the counterion connectivity can reinforce or weaken the LCA-like observation depending on the chain length N , and simply increases the equilibrium nearest surface separation of the rods corresponding to the minimum EPMF to nearly three times the counterion site diameter, whether N is large or small. (iii) If N is large enough, the LCA-like strength tends to be negatively correlated with the electrolyte concentration c over the entire range of the rod surface charge magnitude | σ*| considered; whereas if N drops, the correlation tends to become positive with decrease of the | σ*| value, and particularly for modest | σ*| values, the correlation relationship exhibits an extreme value phenomenon. (iv) In the case of a 1:1 electrolyte, the EPMF effects of the diameters of counterion and coion sites are similar in both situations with and without the counterion connectivity. All of these findings can be explained self-consistently by a recently proposed hydrogen-bonding style mechanism reinforced by one additional concept: flexibility of the counterion chain and the factors affecting it, like N and counterion site valence.

  20. Exploring the therapeutic potential of Ayahuasca: acute intake increases mindfulness-related capacities.

    Science.gov (United States)

    Soler, Joaquim; Elices, Matilde; Franquesa, Alba; Barker, Steven; Friedlander, Pablo; Feilding, Amanda; Pascual, Juan C; Riba, Jordi

    2016-03-01

    Ayahuasca is a psychotropic plant tea used for ritual purposes by the indigenous populations of the Amazon. In the last two decades, its use has expanded worldwide. The tea contains the psychedelic 5-HT2A receptor agonist N,N-dimethyltryptamine (DMT), plus β-carboline alkaloids with monoamine-oxidase-inhibiting properties. Acute administration induces an introspective dream-like experience characterized by visions and autobiographic and emotional memories. Studies of long-term users have suggested its therapeutic potential, reporting that its use has helped individuals abandon the consumption of addictive drugs. Furthermore, recent open-label studies in patients with treatment-resistant depression found that a single ayahuasca dose induced a rapid antidepressant effect that was maintained weeks after administration. Here, we conducted an exploratory study of the psychological mechanisms that could underlie the beneficial effects of ayahuasca. We assessed a group of 25 individuals before and 24 h after an ayahuasca session using two instruments designed to measure mindfulness capacities: The Five Facets Mindfulness Questionnaire (FFMQ) and the Experiences Questionnaire (EQ). Ayahuasca intake led to significant increases in two facets of the FFMQ indicating a reduction in judgmental processing of experiences and in inner reactivity. It also led to a significant increase in decentering ability as measured by the EQ. These changes are classic goals of conventional mindfulness training, and the scores obtained are in the range of those observed after extensive mindfulness practice. The present findings support the claim that ayahuasca has therapeutic potential and suggest that this potential is due to an increase in mindfulness capacities.

  1. Spatial distribution of potential near surface moisture flux at Yucca Mountain

    International Nuclear Information System (INIS)

    Flint, A.L.; Flint, L.E.

    1994-01-01

    An estimate of the areal distribution of present-day surface liquid moisture flux at Yucca Mountain was made using field measured water contents and laboratory measured rock properties. Using available data for physical and hydrologic properties (porosity, saturated hydraulic conductivity, moisture retention functions) of the volcanic rocks, surface lithologic units that are hydrologically similar were delineated. Moisture retention and relative permeability functions were assigned to each surface unit based on the similarity of the mean porosity and saturated hydraulic conductivity of the surface unit to laboratory samples of the same lithology. The potential flux into the mountain was estimated for each surface hydrologic unit using the mean saturated hydraulic conductivity for each unit and assuming all matrix flow. Using measured moisture profiles for each of the surface units, estimates were made of the depth at which seasonal fluctuations diminish and steady state downward flux conditions are likely to exist. The hydrologic properties at that depth were used with the current relative saturation of the tuff, to estimate flux as the unsaturated hydraulic conductivity. This method assumes a unit gradient. The range in estimated flux was 0.02 mm/yr for the welded Tiva Canyon to 13.4 mm/yr for the nonwelded Paintbrush Tuff. The areally averaged flux was 1.4 mm/yr. The major zones of high flux occur to the north of the potential repository boundary where the nonwelded tuffs are exposed in the major drainages

  2. Spatial distribution of potential near surface moisture flux at Yucca Mountain

    International Nuclear Information System (INIS)

    Flint, A.L.; Flint, L.E.

    1994-01-01

    An estimate of the areal distribution of present-day surface liquid moisture flux at Yucca Mountain was made using field measured water contents and laboratory measured rock properties. Using available data for physical and hydrologic properties (porosity, saturated hydraulic conductivity moisture retention functions) of the volcanic rocks, surface lithologic units that are hydrologically similar were delineated. Moisture retention and relative permeability functions were assigned to each surface unit based on the similarity of the mean porosity and saturated hydraulic conductivity of the surface unit to laboratory samples of the same lithology. The potential flux into the mountain was estimated for each surface hydrologic unit using the mean saturated hydraulic conductivity for each unit and assuming all matrix flow. Using measured moisture profiles for each of the surface units, estimates were made of the depth at which seasonal fluctuations diminish and steady state downward flux conditions are likely to exist. The hydrologic properties at that depth were used with the current relative saturation of the tuff, to estimate flux as the unsaturated hydraulic conductivity. This method assumes a unit gradient. The range in estimated flux was 0.02 mm/yr for the welded Tiva Canyon to 13.4 mm/yr for the nonwelded Paintbrush Tuff. The areally averaged flux was 1.4 mm/yr. The major zones of high flux occur to the north of the potential repository boundary where the nonwelded tuffs are exposed in the major drainages

  3. Integrated CLOS and PN Guidance for Increased Effectiveness of Surface to Air Missiles

    Directory of Open Access Journals (Sweden)

    Binte Fatima Tuz ZAHRA

    2017-06-01

    Full Text Available In this paper, a novel approach has been presented to integrate command to line-of-sight (CLOS guidance and proportional navigation (PN guidance in order to reduce miss distance and to increase the effectiveness of surface to air missiles. Initially a comparison of command to line-of-sight guidance and proportional navigation has been presented. Miss distance, variation of angle-of-attack, normal and lateral accelerations and error of missile flight path from direct line-of-sight have been used as noteworthy criteria for comparison of the two guidance laws. Following this comparison a new approach has been proposed for determining the most suitable guidance gains in order to minimize miss distance and improve accuracy of the missile in delivering the warhead, while using CLOS guidance. This proposed technique is based on constrained nonlinear minimization to optimize the guidance gains. CLOS guidance has a further limitation of significant increase in normal and lateral acceleration demands during the terminal phase of missile flight. Furthermore, at large elevation angles, the required angle-of-attack during the terminal phase increases beyond design specifications. Subsequently, a missile with optical sensors only and following just the CLOS guidance has less likelihood to hit high speed targets beyond 45º in elevation plane. A novel approach has thus been proposed to overcome such limitations of CLOS-only guidance for surface to air missiles. In this approach, an integrated guidance algorithm has been proposed whereby the initial guidance law during rocket motor burnout phase remains CLOS, whereas immediately after this phase, the guidance law is automatically switched to PN guidance. This integrated approach has not only resulted in slight increase in range of the missile but also has significantly improved its likelihood to hit targets beyond 30 degrees in elevation plane, thus successfully overcoming various limitations of CLOS

  4. Ab initio ground state phenylacetylene-argon intermolecular potential energy surface and rovibrational spectrum

    DEFF Research Database (Denmark)

    Cybulski, Hubert; Fernandez, Berta; Henriksen, Christian

    2012-01-01

    We evaluate the phenylacetylene-argon intermolecular potential energy surface by fitting a representative number of ab initio interaction energies to an analytic function. These energies are calculated at a grid of intermolecular geometries, using the CCSD(T) method and the aug-cc-pVDZ basis set ...... Institute of Physics. [http://dx.doi.org/10.1063/1.4742153]...

  5. Dipyridamole Body Surface Potential Mapping: Noninvasive Differentiation of Syndrome X from Coronary Artery Disease

    Czech Academy of Sciences Publication Activity Database

    Boudík, F.; Anger, Z.; Aschermann, M.; Vojáček, J.; Tomečková, Marie

    2002-01-01

    Roč. 35, č. 3 (2002), s. 181-191 ISSN 0022-0736 R&D Projects: GA MZd IZ4038 Keywords : body surface potential mapping * dipyridamole * coronary artery disease * syndrome X Subject RIV: BD - Theory of Information Impact factor: 0.599, year: 2002

  6. Nanoscale surface potential imaging of the photocatalytic TiO2 films on aluminum

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Dirscherl, Kai; Canulescu, Stela

    2013-01-01

    The change in the surface potential of TiO2 coatings upon UV-illumination was investigated on the nanoscale using Scanning Kelvin Probe Force microscopy and on the micro-scale using photo-electrochemical measurements. A good correlation between the two techniques was obtained. The changes in the ...

  7. A new analytical potential energy surface for the adsorption systemk CO/Cu(100)

    NARCIS (Netherlands)

    Marquardt, R.; Cuvelier, F.; Olsen, R.A.; Baerends, E.J.; Tremblay, J.C.; Saalfrank, P.

    2010-01-01

    Electronic structure data and analytical representations of the potential energy surface for the adsorption of carbon monoxide on a crystalline copper Cu(100) substrate are reviewed. It is found that a previously published and widely used analytical hypersurface for this process [J. C. Tully, M.

  8. Ab initio potential-energy surface and rovibrational states of the HCN-HCl complex

    NARCIS (Netherlands)

    Avoird, A. van der; Pedersen, T.B.; Dhont, G.S.F.; Fernandez, B.; Koch, H.

    2006-01-01

    A four-dimensional intermolecular potential-energy surface has been calculated for the HCN-HCl complex, with the use of the coupled cluster method with single and double excitations and noniterative inclusion of triples. Data for more than 13 000 geometries were represented by an angular expansion

  9. Increased migration of monocytes in essential hypertension is associated with increased transient receptor potential channel canonical type 3 channels

    DEFF Research Database (Denmark)

    Zhao, Zhigang; Ni, Yinxing; Chen, Jing

    2012-01-01

    in a microchemotaxis chamber using chemoattractants formylated peptide Met-Leu-Phe (fMLP) and tumor necrosis factor-α (TNF-α). Proteins were identified by immunoblotting and quantitative in-cell Western assay. The effects of TRP channel-inhibitor 2-aminoethoxydiphenylborane (2-APB) and small interfering RNA knockdown...... of TRPC3 were investigated. We observed an increased fMLP-induced migration of monocytes from hypertensive patients compared with normotensive control subjects (246 ± 14% vs 151 ± 10%). The TNF-α-induced migration of monocytes in patients with essential hypertension was also significantly increased...... compared to normotensive control subjects (221 ± 20% vs 138 ± 18%). In the presence of 2-APB or after siRNA knockdown of TRPC3 the fMLP-induced monocyte migration was significantly blocked. The fMLP-induced changes of cytosolic calcium were significantly increased in monocytes from hypertensive patients...

  10. Intrinsic Charge Trapping Observed as Surface Potential Variations in diF-TES-ADT Films.

    Science.gov (United States)

    Hoffman, Benjamin C; McAfee, Terry; Conrad, Brad R; Loth, Marsha A; Anthony, John E; Ade, Harald W; Dougherty, Daniel B

    2016-08-24

    Spatial variations in surface potential are measured with Kelvin probe force microscopy for thin films of 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophenes (diF-TES-ADT) grown on SiO2 and silane-treated SiO2 substrates by organic molecular beam deposition. The variations are observed both between and within grains of the polycrystalline organic film and are quantitatively different than electrostatic variations on the substrate surfaces. The skewness of surface potential distributions is larger on SiO2 than on HMDS-treated substrates. This observation is attributed to the impact of substrate functionalization on minimizing intrinsic crystallographic defects in the organic film that can trap charge.

  11. AFM-assisted fabrication of thiol SAM pattern with alternating quantified surface potential

    Directory of Open Access Journals (Sweden)

    Simons Janet

    2011-01-01

    Full Text Available Abstract Thiol self-assembled monolayers (SAMs are widely used in many nano- and bio-technology applications. We report a new approach to create and characterize a thiol SAMs micropattern with alternating charges on a flat gold-coated substrate using atomic force microscopy (AFM and Kelvin probe force microscopy (KPFM. We produced SAMs-patterns made of alternating positively charged, negatively charged, and hydrophobic-terminated thiols by an automated AFM-assisted manipulation, or nanografting. We show that these thiol patterns possess only small topographical differences as revealed by AFM, and distinguished differences in surface potential (20-50 mV, revealed by KPFM. The pattern can be helpful in the development of biosensor technologies, specifically for selective binding of biomolecules based on charge and hydrophobicity, and serve as a model for creating surfaces with quantified alternating surface potential distribution.

  12. The Potential Well-Depth U Constraints on the Surface Gravitational ...

    Indian Academy of Sciences (India)

    1, where the central energy density is in units of the density of ordinary nuclear matter. Figure 1 shows that the surface gravitational red-shift increases as the central energy density increases. The mass of a PNS as a function of the central energy density is given in Fig. 2. Part AB of these curves correspond to stable stars ...

  13. Bacterial production of sunscreen pigments increase arid land soil surface temperature

    Science.gov (United States)

    Couradeau, Estelle; Karaoz, Ulas; Lim, HsiaoChien; Nunes da Rocha, Ulisses; Northern, Trent; Brodie, Eoin; Garcia-Pichel, Ferran

    2015-04-01

    Biological Soil Crusts (BSCs) are desert top soils formations built by complex microbial communities and dominated by the filamentous cyanobacterium Microcoleus sp. BSCs cover extensive desert areas where they correspond to millimeters size mantles responsible of soil stability and fertility. Despite their ecological importance, little is known about how these communities will endure climate change. It has been shown in North America that different species of Microcoleus showed distinct temperature preferences and that their continental biogeography may be susceptible to small changes in temperature with unknown consequences for the ecosystem function. Using a combination of physical, biochemical and microbiological analyses to characterize a successional gradient of crust maturity from light to dark BSCs (Moab, Utah) we found that the concentration of scytonemin (a cyanobacterial sunscreen pigment) increased with crust maturity. We also confirmed that scytonemin was by far the major pigment responsible of light absorption in the visible spectrum in BSCs, and is then responsible of the darkening of the BSCs (i.e decrease of albedo) with maturity. We measured the surface temperature and albedo and found, as predicted, a negative linear relationship between these two parameters. The decrease in albedo across the gradient of crust maturity corresponded to an increase in surface temperature up to 10° C. Upon investigation of microbial community composition using SSU rRNA gene analysis, we demonstrate that warmer crust surface temperatures (decreased albedo) are associated with a replacement of the dominant cyanobacterium; the thermosensitive Microcoleus sp. being replaced by a thermotolerant Microcoleus sp. in darker BSCs. This study supports at the local scale a finding previously made at the continental scale, but also sheds light on the importance of scytonemin as a significant warmer of soils with important consequences for BSC composition and function. Based on

  14. Potential for increased wind-generated electricity utilization using heat pumps in urban areas

    International Nuclear Information System (INIS)

    Waite, Michael; Modi, Vijay

    2014-01-01

    Highlights: • Large-scale wind power and increased electric heat pumps were evaluated. • A deterministic model of wind power and electricity demand was developed. • Sub-models for space heating and domestic hot water demand were developed. • Increased use of heat pumps can improve the viability of large-scale wind power. • Larger wind power capacity can meet a target utilization rate with more heat pumps. - Abstract: The U.S. has substantial wind power potential, but given wind’s intermittent availability and misalignment with electricity demand profiles, large-scale deployment of wind turbines could result in high electricity costs due to energy storage requirements or low utilization rates. While fuel switching and heat pumps have been proposed as greenhouse gas (GHG) emissions and energy reduction strategies at the building scale, this paper shows that heat pump adoption could have additional system-wide benefits by increasing the utilization of wind-generated electricity. A model was developed to evaluate the effects of coupling large-scale wind power installations in New York State with increased use of electric heat pumps to meet a portion of space heating and domestic hot water (DHW) demands in New York City. The analysis showed significant increases in wind-generated electricity utilization with increased use of heat pumps, allowing for higher installed capacity of wind power. One scenario indicates that 78.5% annual wind-generated electricity utilization can be achieved with 3 GW of installed wind power capacity generated electricity equal to 20% of existing NYC annual electricity demand; if 20% of space heating and DHW demands are provided by heat pumps, the 78.5% utilization rate can be achieved with an increase of total wind power capacity to 5 GW. Therefore, this integrated supply–demand approach could provide additional system-wide emissions reductions

  15. Potential dependence of surface crystal structure of iron passive films in borate buffer solution

    International Nuclear Information System (INIS)

    Deng, Huihua; Nanjo, Hiroshi; Qian, Pu; Santosa, Arifin; Ishikawa, Ikuo; Kurata, Yoshiaki

    2007-01-01

    The effect of passivation potential on surface crystal structure, apparent thickness and passivity of oxide films formed on pure iron prepared by plasma sputter deposition was investigated. The crystallinity was improved with passivation potential and the width of atomically flat terraces was expanded to 6 nm when passivating at 750 mV for 15 min, as observed by ex situ scanning tunneling microscopy (STM) after aging in air (<30% RH). Apparent thickness and passivity are linearly dependent on passivation potential. The former weakly depends on passivation duration, the latter strongly depends on passivation duration. This is well explained by the correlation between crystal structure and passivity

  16. Refined potentials for rare gas atom adsorption on rare gas and alkali-halide surfaces

    Science.gov (United States)

    Wilson, J. W.; Heinbockel, J. H.; Outlaw, R. A.

    1985-01-01

    The utilization of models of interatomic potential for physical interaction to estimate the long range attractive potential for rare gases and ions is discussed. The long range attractive force is calculated in terms of the atomic dispersion properties. A data base of atomic dispersion parameters for rare gas atoms, alkali ion, and halogen ions is applied to the study of the repulsive core; the procedure for evaluating the repulsive core of ion interactions is described. The interaction of rare gas atoms on ideal rare gas solid and alkali-halide surfaces is analyzed; zero coverage absorption potentials are derived.

  17. Quantifying the potential for reservoirs to secure future surface water yields in the world’s largest river basins

    Science.gov (United States)

    Liu, Lu; Parkinson, Simon; Gidden, Matthew; Byers, Edward; Satoh, Yusuke; Riahi, Keywan; Forman, Barton

    2018-04-01

    Surface water reservoirs provide us with reliable water supply, hydropower generation, flood control and recreation services. Yet reservoirs also cause flow fragmentation in rivers and lead to flooding of upstream areas, thereby displacing existing land-use activities and ecosystems. Anticipated population growth and development coupled with climate change in many regions of the globe suggests a critical need to assess the potential for future reservoir capacity to help balance rising water demands with long-term water availability. Here, we assess the potential of large-scale reservoirs to provide reliable surface water yields while also considering environmental flows within 235 of the world’s largest river basins. Maps of existing cropland and habitat conservation zones are integrated with spatially-explicit population and urbanization projections from the Shared Socioeconomic Pathways to identify regions unsuitable for increasing water supply by exploiting new reservoir storage. Results show that even when maximizing the global reservoir storage to its potential limit (∼4.3–4.8 times the current capacity), firm yields would only increase by about 50% over current levels. However, there exist large disparities across different basins. The majority of river basins in North America are found to gain relatively little firm yield by increasing storage capacity, whereas basins in Southeast Asia display greater potential for expansion as well as proportional gains in firm yield under multiple uncertainties. Parts of Europe, the United States and South America show relatively low reliability of maintaining current firm yields under future climate change, whereas most of Asia and higher latitude regions display comparatively high reliability. Findings from this study highlight the importance of incorporating different factors, including human development, land-use activities, and climate change, over a time span of multiple decades and across a range of different

  18. Evaluation of surface charge density and surface potential by electrophoretic mobility for solid lipid nanoparticles and human brain-microvascular endothelial cells.

    Science.gov (United States)

    Kuo, Yung-Chih; Chen, I-Chun

    2007-09-27

    Electrophoretic mobility, zeta potential, surface charge density, and surface potential of cacao butter-based solid lipid nanoparticles (SLN) and human brain-microvascular endothelial cells (HBMEC) were analyzed in this study. Electrophoretic mobility and zeta potential were determined experimentally. Surface charge density and surface potential were evaluated theoretically via incorporation of ion condensation theory with the relationship between surface charge density and surface potential. The results revealed that the lower the pH value, the weaker the electrostatic properties of the negatively charged SLN and HBMEC. A higher content of cacao butter or a slower stirring rate yielded a larger SLN and stronger surface electricity. On the contrary, storage led to instability of SLN suspension and weaker electrical behavior because of hydrolysis of ionogenic groups on the particle surfaces. Also, high H+ concentration resulted in excess adsorption of H+ onto HBMEC, rendering charge reversal and cell death. The largest normalized discrepancy between surface potential and zeta potential occurred at pH = 7. For a fixed biocolloidal species, the discrepancy was nearly invariant at high pH value. However, the discrepancy followed the order of electrical intensity for HBMEC system at low pH value because mammalian cells were sensitive to H+. The present study provided a practical method to obtain surface charge properties by capillary electrophoresis.

  19. Rapid Adjustments Cause Weak Surface Temperature Response to Increased Black Carbon Concentrations

    Science.gov (United States)

    Stjern, Camilla Weum; Samset, Bjørn Hallvard; Myhre, Gunnar; Forster, Piers M.; Hodnebrog, Øivind; Andrews, Timothy; Boucher, Olivier; Faluvegi, Gregory; Iversen, Trond; Kasoar, Matthew; Kharin, Viatcheslav; Kirkevâg, Alf; Lamarque, Jean-François; Olivié, Dirk; Richardson, Thomas; Shawki, Dilshad; Shindell, Drew; Smith, Christopher J.; Takemura, Toshihiko; Voulgarakis, Apostolos

    2017-11-01

    We investigate the climate response to increased concentrations of black carbon (BC), as part of the Precipitation Driver Response Model Intercomparison Project (PDRMIP). A tenfold increase in BC is simulated by nine global coupled-climate models, producing a model median effective radiative forcing of 0.82 (ranging from 0.41 to 2.91) W m-2, and a warming of 0.67 (0.16 to 1.66) K globally and 1.24 (0.26 to 4.31) K in the Arctic. A strong positive instantaneous radiative forcing (median of 2.10 W m-2 based on five of the models) is countered by negative rapid adjustments (-0.64 W m-2 for the same five models), which dampen the total surface temperature signal. Unlike other drivers of climate change, the response of temperature and cloud profiles to the BC forcing is dominated by rapid adjustments. Low-level cloud amounts increase for all models, while higher-level clouds are diminished. The rapid temperature response is particularly strong above 400 hPa, where increased atmospheric stabilization and reduced cloud cover contrast the response pattern of the other drivers. In conclusion, we find that this substantial increase in BC concentrations does have considerable impacts on important aspects of the climate system. However, some of these effects tend to offset one another, leaving a relatively small median global warming of 0.47 K per W m-2—about 20% lower than the response to a doubling of CO2. Translating the tenfold increase in BC to the present-day impact of anthropogenic BC (given the emissions used in this work) would leave a warming of merely 0.07 K.

  20. Monolayer Phases of a Dipolar Perylene Derivative on Au(111) and Surface Potential Build-Up in Multilayers.

    Science.gov (United States)

    Niederhausen, Jens; Kersell, Heath R; Christodoulou, Christos; Heimel, Georg; Wonneberger, Henrike; Müllen, Klaus; Rabe, Jürgen P; Hla, Saw-Wai; Koch, Norbert

    2016-04-19

    9-(Bis-p-tert-octylphenyl)-amino-perylene-3,4-dicarboxy anhydride (BOPA-PDCA) is a strongly dipolar molecule representing a group of asymmetrically substituted perylenes that are employed in dye-sensitized solar cells and hold great promise for discotic liquid crystal applications. Thin BOPA-PDCA films with orientated dipole moments can potentially be used to tune the energy-level alignment in electronic devices and store information. To help assessing these prospects, we here elucidate the molecular self-assembly and electronic structure of BOPA-PCDA employing room temperature scanning tunneling microscopy and spectroscopy in combination with ultraviolet and X-ray photoelectron spectroscopies. BOPA-PCDA monolayers on Au(111) exclusively form in-plane antiferroelectric phases. The molecular arrangements, the increase of the average number of molecules per unit cell via ripening, and the rearrangement upon manipulation with the STM tip indicate an influence of the dipole moment on the molecular assembly and the rearrangement. A slightly preferred out-of-plane orientation of the molecules in the multilayer induces a surface potential of 1.2 eV. This resembles the giant surface potential effect that was reported for vacuum-deposited tris(8-hydroxyquinoline)aluminum and deemed applicable for data storage. Notably, the surface potential in the case of BOPA-PDCA can in part be reversibly removed by visible light irradiation.

  1. Anticancer drugs in Portuguese surface waters - Estimation of concentrations and identification of potentially priority drugs.

    Science.gov (United States)

    Santos, Mónica S F; Franquet-Griell, Helena; Lacorte, Silvia; Madeira, Luis M; Alves, Arminda

    2017-10-01

    Anticancer drugs, used in chemotherapy, have emerged as new water contaminants due to their increasing consumption trends and poor elimination efficiency in conventional water treatment processes. As a result, anticancer drugs have been reported in surface and even drinking waters, posing the environment and human health at risk. However, the occurrence and distribution of anticancer drugs depend on the area studied and the hydrological dynamics, which determine the risk towards the environment. The main objective of the present study was to evaluate the risk of anticancer drugs in Portugal. This work includes an extensive analysis of the consumption trends of 171 anticancer drugs, sold or dispensed in Portugal between 2007 and 2015. The consumption data was processed aiming at the estimation of predicted environmental loads of anticancer drugs and 11 compounds were identified as potentially priority drugs based on an exposure-based approach (PEC b > 10 ng L -1 and/or PEC c > 1 ng L -1 ). In a national perspective, mycophenolic acid and mycophenolate mofetil are suspected to pose high risk to aquatic biota. Moderate and low risk was also associated to cyclophosphamide and bicalutamide exposition, respectively. Although no evidences of risk exist yet for the other anticancer drugs, concerns may be associated with long term effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Potential of non-invasive esophagus cancer detection based on urine surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Huang, Shaohua; Wang, Lan; Chen, Weisheng; Feng, Shangyuan; Lin, Juqiang; Huang, Zufang; Chen, Guannan; Li, Buhong; Chen, Rong

    2014-11-01

    Non-invasive esophagus cancer detection based on urine surface-enhanced Raman spectroscopy (SERS) analysis was presented. Urine SERS spectra were measured on esophagus cancer patients (n = 56) and healthy volunteers (n = 36) for control analysis. Tentative assignments of the urine SERS spectra indicated some interesting esophagus cancer-specific biomolecular changes, including a decrease in the relative content of urea and an increase in the percentage of uric acid in the urine of esophagus cancer patients compared to that of healthy subjects. Principal component analysis (PCA) combined with linear discriminant analysis (LDA) was employed to analyze and differentiate the SERS spectra between normal and esophagus cancer urine. The diagnostic algorithms utilizing a multivariate analysis method achieved a diagnostic sensitivity of 89.3% and specificity of 83.3% for separating esophagus cancer samples from normal urine samples. These results from the explorative work suggested that silver nano particle-based urine SERS analysis coupled with PCA-LDA multivariate analysis has potential for non-invasive detection of esophagus cancer.

  3. Resource potential methods using for efficiency of activities in the region increase

    Directory of Open Access Journals (Sweden)

    M. P. Vasiliev

    2016-01-01

    Full Text Available The article considers impact methods on the economic results, the effectiveness of the regional economic complex should be based on a high quality of the basic characteristics classification of the region state. Application composition techniques to ensure a comprehensive impact on the achievement of this goal should in synthesized form to union, adopt a target orientation of development of the region with the parameters objectively revealing his condition. Ensuring organizational, economic, financial and investment techniques to achieve the planned targets and requires specifying align resource potential of the region with the available capacity of the regional economic complex to promote economic growth, improve the efficiency of operations. The main characteristics of the potential resource opportunities in the region are the skill level of workers, the degree of depreciation of fixed assets and their renewability, increased innovation in the region, its branches and facilities, strengthening of competitive advantages, the annual average number of employees, the cost of fixed and current assets, financial stability. In the region the opportunity to potentially affect the ability of its structural components to achieve the financial and economic performance targets acts as efficiency ability to provide stable dynamics of regional production efficiency, enhance the level of benefits to achieve the planned efficiency used (consumed resource. Applying of certain methods or their entire structure, created to provide a comprehensive impact on the goal achievement, in the synthesized form of target orientation combines regional development with the parameters most objectively revealing his condition. Achieving the appropriate organizational, economic, financial, investment or other measures to achieve planned targets that are expressed by the level of efficiency of activity in the conditions of the most complete involvement and intensity of use in

  4. Insight into induced charges at metal surfaces and biointerfaces using a polarizable Lennard-Jones potential.

    Science.gov (United States)

    Geada, Isidro Lorenzo; Ramezani-Dakhel, Hadi; Jamil, Tariq; Sulpizi, Marialore; Heinz, Hendrik

    2018-02-19

    Metallic nanostructures have become popular for applications in therapeutics, catalysts, imaging, and gene delivery. Molecular dynamics simulations are gaining influence to predict nanostructure assembly and performance; however, instantaneous polarization effects due to induced charges in the free electron gas are not routinely included. Here we present a simple, compatible, and accurate polarizable potential for gold that consists of a Lennard-Jones potential and a harmonically coupled core-shell charge pair for every metal atom. The model reproduces the classical image potential of adsorbed ions as well as surface, bulk, and aqueous interfacial properties in excellent agreement with experiment. Induced charges affect the adsorption of ions onto gold surfaces in the gas phase at a strength similar to chemical bonds while ions and charged peptides in solution are influenced at a strength similar to intermolecular bonds. The proposed model can be applied to complex gold interfaces, electrode processes, and extended to other metals.

  5. Potential dependent adhesion forces on bare and underpotential deposition modified electrode surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Serafin, J.M.; Hsieh, S.J.; Monahan, J.; Gewirth, A.A. [Univ. of Illinois, Urbana, IL (United States)

    1998-12-03

    Adhesion force measurements are used to determine the potential dependence of the force of adhesion between a Si{sub 3}N{sub 4} cantilever and a Au(111) surface modified by the underpotential deposition (upd) of Bi or Cu in acid solution or by oxide formation. The measured work of adhesion is near zero for most of the potential region examined in Bi upd but rises after the formation of a full Bi monolayer. The work of adhesion is high at positive potentials for Cu upd but then decreases as the Cu partial and full monolayers are formed. The work of adhesion is low in the oxide region on Au(111) but rises following the sulfate disordering transition at 1.1 V vs NHE. These results are interpreted in terms of the degree of solvent order on the electrode surface.

  6. Increasing educational indebtedness influences medical students to pursue specialization: a military recruitment potential?

    Science.gov (United States)

    Bale, Asha G; Coutinho, Karl; Swan, Kenneth G; Heinrich, George F

    2013-02-01

    Cost of medical education and student indebtedness has increased dramatically. This study surveyed medical students on educational debt, educational costs, and whether indebtedness influenced career choice. Responses should impact (1) Department of Defense (DoD) recruitment of physicians and (2) future of primary care. The authors surveyed 188 incoming medical students (University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Class of 2012) concerning educational indebtedness, perceptions about educational costs, and plans regarding loan repayment. Data were analyzed and expressed as mean +/- standard error. Students with loans anticipated their medical educational costs to be $155,993. 62% felt costs were "exorbitant," and 28% "appropriate." 64% planned to specialize, whereas only 9% chose primary care. 28% of students planning specialization said income potential influenced their decision. 70% of students said cost was a factor in choosing New Jersey Medical School over a more expensive school. Students anticipated taking about 10 years to repay loans. As medical educational costs and student indebtedness rise, students are choosing less costly education and career paths with higher potential future earnings. These trends will negatively impact health care availability, accessibility, and cost. DoD programs to provide financial assistance in exchange for military service are not well publicized. These findings should increase DoD recruitment opportunities.

  7. Increased subepithelial vascularization and VEGF expression reveal potentially malignant changes in human oral mucosa lesions.

    Science.gov (United States)

    Gandolfo, Mariana; Keszler, Alicia; Lanfranchi, Hector; Itoiz, Maria Elina

    2011-04-01

    The objective of this study was to provide evidence that the magnitude of angiogenesis induced by oral mucosa epithelium with potentially malignant lesions is related to the degree of epithelial aggressiveness. We evaluated 96 biopsies that included: (1) leukoplakia with and without dysplasia, (2) nontumoral borders adjacent to squamous cell carcinomas with and without dysplasia, and (3) normal oral mucosa. Number, size, and localization of vessels labeled immunohistochemically for the antigen CD34 were assessed by image analysis using a software developed "ad hoc." All vascular sections and those localized immediately below the epithelium (sub-basal vessels) were separately evaluated in areas 30-μm deep. Vascular endothelial growth factor (VEGF) expression was labeled immunohistochemically and evaluated semiquantitatively against a standard. Leukoplakia and nontumoral borders adjacent to carcinomas exhibited an increase in VEGF expression and in subepithelial vascularization. This increase was significantly greater in leukoplakia with dysplastic changes than in leukoplakia without dysplasia. Conversely, no differences were observed between epithelia with and without dysplasia adjacent to carcinomas. Demonstration of expression of epithelial VEGF and sub-basal vascularization could be an additional aid for evaluation of the severity of potentially malignant lesions in oral mucosa routine biopsies. Copyright © 2011 Mosby, Inc. All rights reserved.

  8. Resistance to pyrethroids and organophosphates increased fitness and predation potential of Chrysoperla carnae (Neuroptera: Chrysopidae).

    Science.gov (United States)

    Pathan, Attaullah Khan; Sayyed, Ali H; Aslam, Muhammad; Liu, T X; Razzaq, Muhammad; Gillani, Waseem Ahmed

    2010-06-01

    Insect natural enemies can develop resistance to insecticides in the field like their host insects. Recently, a high level of resistance to several groups of insecticides from Pakistan has been shown in Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae). Here, we were interested to determine the impact of insecticides resistance on fitness of various populations of C. carnea collected over three consecutive years (2005-2007) from different areas of Pakistan. The populations were examined for intrinsic rate of population increase, growth index, fertility, eggs viability, survival to adult hood and doubling time. The results of the study showed significantly higher intrinsic rate of population increase in insecticides resistant population compared with laboratory susceptible population Lab-PK. Similarly, the resistant population laid more numbers of eggs, which were significantly more viable than susceptible population. The survival to adulthood and doubling time were greater in field populations than the susceptible. The most intriguing finding was that the predation potential of all resistant populations was significantly great compared with Lab-PK. The data point to the fact that resistance to insecticides had positive impact on C. carnea, which could be used in integrated pest management system. The potential for introducing these natural enemies into cropping systems where they have not developed resistance could be a useful tactic for management of various insect pests.

  9. An increasing, potentially measles-susceptible population over time after vaccination in Korea.

    Science.gov (United States)

    Kang, Hae Ji; Han, Young Woo; Kim, Su Jin; Kim, You-Jin; Kim, A-Reum; Kim, Joo Ae; Jung, Hee-Dong; Eom, Hye Eun; Park, Ok; Kim, Sung Soon

    2017-07-24

    In Korea, measles occurs mainly in infants measles infection. Age-specific measles seroprevalence was evaluated by performing enzyme immunoassays and plaque reduction-neutralization tests on 3050 subjects aged 0-50years (birth cohort 1964-2014) and 480 subjects aged 2-30years (birth cohort 1984-2012). The overall seropositivity and measles antibody concentrations were 71.5% and 1366mIU/mL, respectively. Progressive decline in antibody levels and seropositivity were observed over time after vaccination in infants, adolescents, and young adults. The accumulation of potentially susceptible individuals in the population was confirmed by comparing data from 2010 and 2014 seroprevalence surveys. The statistical correlation between measles incidence and measles seronegativity was determined. Waning levels of measles antibodies with increasing time post-vaccination suggests that measles susceptibility is potentially increasing in Korea. This trend may be related to limitations of vaccine-induced immunity in the absence of natural boosting by the wild virus, compared to naturally acquired immunity triggered by measles infection. This study provides an important view into the current measles herd immunity in Korea. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Microbial Potential for Ecosystem N Loss Is Increased by Experimental N Deposition.

    Directory of Open Access Journals (Sweden)

    Zachary B Freedman

    Full Text Available Fossil fuel combustion and fertilizer use has increased the amount of biologically available N entering terrestrial ecosystems. Nonetheless, our understanding of how anthropogenic N may alter the physiological mechanisms by which soil microorganisms cycle N in soil is still developing. Here, we applied shotgun metagenomics to a replicated long-term field experiment to determine how two decades of experimental N deposition, at a rate expected by mid-century, has affected the genetic potential of the soil microbial community to cycle N in soils. Experimental N deposition lead to a significant and persistent increase in functional assemblages mediating N cycle transformations associated with ecosystem N loss (i.e., denitrification and nitrification, whereas functional assemblages associated with N input and retention (i.e., N fixation and microbial N assimilation were less positively affected. Furthermore, the abundance and composition of microbial taxa, as well as functional assemblages involved in housekeeping functions (i.e., DNA replication were unaffected by experimental N deposition. Taken together, our results suggest that functional genes and gene pathways associated with ecosystem N loss have been favored by experimental N deposition, which may represent a genetic mechanism fostering increased N loss as anthropogenic N deposition increases in the future.

  11. [Burden of smoking-related disease and potential impact of cigarette price increase in Peru].

    Science.gov (United States)

    Bardach, Ariel E; Caporale, Joaquín E; Alcaraz, Andrea; Augustovski, Federico; Huayanay-Falconí, Leandro; Loza-Munarriz, Cesar; Hernández-Vásquez, Akram; Pichon-Riviere, Andrés

    2016-01-01

    . To calculate the burden of smoking-related disease and evaluate the potential economic and health impact of tax-induced cigarette price increase in Peru. A microsimulation model was used to estimate smoking-attributable impact on mortality, quality of life, and costs associated with heart and cerebrovascular disease, chronic obstructive pulmonary disease, pneumonia, lung cancer, and another nine cancers. Three scenarios, involving increased taxes, were evaluated. . A yearly total of 16,719 deaths, 6,926 cancer diagnoses, 7,936 strokes, and 7,548 hospital admissions due to cardiovascular disease can be attributed to smoking in Peru. Similarly, 396,069 years of life are lost each year from premature death and disability, and the cost of treating smoking-attributable health issues rises to 2,500 million soles (PEN 2015). Currently, taxes on tobacco cover only 9.1% of this expense. If cigarette prices were to increase by 50% over the next 10 years, 13,391 deaths, 6,210 cardiovascular events, and 5,361 new cancers could be prevented, representing an economic benefit of 3,145 million (PEN) in savings in health costs and increases in tax revenues. . Smoking-attributable burden of disease and costs to the health system are very high in Peru. Higher cigarette taxes could have substantial health and economic benefits for the country.

  12. Potential future increase in extreme one-hour precipitation events over Europe due to climate change.

    Science.gov (United States)

    Larsen, A N; Gregersen, I B; Christensen, O B; Linde, J J; Mikkelsen, P S

    2009-01-01

    In this study the potential increase of extreme precipitation in a future warmer European climate has been examined. Output from the regional climate model (RCM) HIRHAM4 covering Europe has been analysed for two periods, a control period 1961-1990 and a scenario 2071-2100, the latter following the IPCC scenario A2. The model has a resolution of about 12 km, which is unique compared with existing RCM studies that typically operate at 25-50 km scale, and make the results relevant to hydrological phenomena occurring at the spatial scale of the infrastructure designed to drain off rainfall in large urban areas. Extreme events with one- and 24-hour duration were extracted using the Partial Duration Series approach, a Generalized Pareto Distribution was fitted to the data and T-year events for return periods from 2 to 100 years were calculated for the control and scenario period in model cells across Europe. The analysis shows that there will be an increase of the intensity of extreme events generally in Europe; Scandinavia will experience the highest increase and southern Europe the lowest. A 20 year 1-hour precipitation event will for example become a 4 year event in Sweden and a 10 year event in Spain. Intensities for short durations and high return periods will increase the most, which implies that European urban drainage systems will be challenged in the future.

  13. Kinetoplastid membrane protein-11 is present in promastigotes and amastigotes of Leishmania amazonensis and its surface expression increases during metacyclogenesis

    Directory of Open Access Journals (Sweden)

    Denise CS Matos

    2010-05-01

    Full Text Available Kinetoplastid membrane protein-11 (KMP-11, a protein present in all kinetoplastid protozoa, is considered a potential candidate for a leishmaniasis vaccine. A suitable leishmaniasis vaccine candidate molecule must be expressed in amastigotes, the infective stage for mammals. However, the expression of KMP-11 in Leishmania amastigotes has been a subject of controversy. We evaluated the expression of this molecule in logarithmic and stationary growth phase promastigotes, as well as in amastigotes, of Leishmania amazonensis by immunoblotting, flow cytometry and immunocytochemistry, using a monoclonal antibody against KMP-11. We found that KMP-11 is present in promastigotes and amastigotes. In both stages, the protein was found in association with membrane structures (at the cell surface, flagellar pocket and intracellular vesicles. More importantly, its surface expression is higher in amastigotes than in promastigotes and increases during metacyclogenesis. The increased expression of KMP-11 in metacyclic promastigotes, and especially in amastigotes, indicates a role for this molecule in the parasite relationship with the mammalian host. The presence of this molecule in amastigotes is consistent with the previously demonstrated immunoprotective capacity of vaccine prototypes based on the KMP-11-coding gene and the presence of humoral and cellular immune responses to KMP-11 in Leishmania-infected humans and animals.

  14. Increased cloud activation potential of secondary organic aerosol for atmospheric mass loadings

    Directory of Open Access Journals (Sweden)

    S. M. King

    2009-05-01

    Full Text Available The effect of organic particle mass loading from 1 to ≥100 μg m−3 on the cloud condensation nuclei (CCN properties of mixed organic-sulfate particles was investigated in the Harvard Environmental Chamber. Mixed particles were produced by the condensation of organic molecules onto ammonium sulfate particles during the dark ozonolysis of α-pinene. A continuous-flow mode of the chamber provided stable conditions over long time periods, allowing for signal integration and hence increased measurement precision at low organic mass loadings representative of atmospheric conditions. CCN activity was measured at eight mass loadings for 80- and 100-nm particles grown on 50-nm sulfate seeds. A two-component (organic/sulfate Köhler model, which included the particle heterogeneity arising from DMA size selection and from organic volume fraction for the selected 80- and 100-nm particles, was used to predict CCN activity. For organic mass loadings of 2.9 μg m−3 and greater, the observed activation curves were well predicted using a single set of physicochemical parameters for the organic component. For mass loadings of 1.74 μg m−3 and less, the observed CCN activity increased beyond predicted values using the same parameters, implying changed physicochemical properties of the organic component. A sensitivity analysis suggests that a drop in surface tension must be invoked to explain quantitatively the CCN observations at low SOA particle mass loadings. Other factors, such as decreased molecular weight, increased density, or increased van't Hoff factor, can contribute to the explanation but are quantitatively insufficient as the full explanation.

  15. Increased event-related potentials and alpha-, beta- and gamma-activity associated with intentional actions

    Directory of Open Access Journals (Sweden)

    Susanne eKarch

    2016-01-01

    Full Text Available Objective: Internally guided actions are defined as being purposeful, self-generated and offering choices between alternatives. Intentional actions are essential to reach individual goals. In previous empirical studies, internally guided actions were predominantly related to functional responses in frontal and parietal areas. The aim of the present study was to distinguish event-related potentials and oscillatory responses of intentional actions and externally guided actions. In addition, we compared neurobiological findings of the decision which action to perform with those referring to the decision whether or not to perform an action. Methods: Twenty-eight subjects participated in adapted go/nogo paradigms, including a voluntary selection condition allowing participants to [1] freely decide whether to press the response button or [2] to decide whether they wanted to press the response button with the right index finger or the left index finger. Results: The reaction times were increased when participants freely decided whether and how they wanted to respond compared to the go condition. Intentional processes were associated with a fronto-centrally located N2 and P3 potential. N2 and P3 amplitudes were increased during intentional actions compared to instructed responses (go. In addition, increased activity in the alpha-, beta- and gamma-frequency range was shown during voluntary behaviour rather than during externally-guided responses. Conclusion: These results may indicate that an additional cognitive process is needed for intentional actions compared to instructed behaviour. However, the neural responses were comparatively independent of the kind of decision that was made (1. decision which action to perform; 2. decision whether or not to perform an action. Significance: The study demonstrates the importance of fronto-central alpha-, beta- and gamma oscillations for voluntary behaviour.

  16. The Role of Anion Adsorption in the Effect of Electrode Potential on Surface Plasmon Resonance Response.

    Science.gov (United States)

    Laurinavichyute, Veronika K; Nizamov, Shavkat; Mirsky, Vladimir M

    2017-06-20

    Surface plasmon resonance, being widely used in bioanalytics and biotechnology, is influenced by the electrical potential of the resonant gold layer. To evaluate the mechanism of this effect, we have studied it in solutions of various inorganic electrolytes. The magnitude of the effect decreases according to the series: KBr>KCl>KF>NaClO 4 . The data were treated by using different models of the interface. A quantitative description was obtained for the model, which takes into account the local dielectric function of gold being affected by the free electron charge, diffuse ionic layer near the gold/water interface, and specific adsorption of halides to the gold surface with partial charge transfer. Taking into account that most biological experiments are performed in chloride-containing solutions, detailed analysis of the model at these conditions was performed. The results indicate that the chloride adsorption is the main mechanism for the influence of potential on the surface plasmon resonance. The dependencies of surface concentration and residual charge of chloride on the applied potential were determined. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Global potential energy surface of ground state singlet spin O4

    Science.gov (United States)

    Mankodi, Tapan K.; Bhandarkar, Upendra V.; Puranik, Bhalchandra P.

    2018-02-01

    A new global potential energy for the singlet spin state O4 system is reported using CASPT2/aug-cc-pVTZ ab initio calculations. The geometries for the six-dimensional surface are constructed using a novel point generation scheme that employs randomly generated configurations based on the beta distribution. The advantage of this scheme is apparent in the reduction of the number of required geometries for a reasonably accurate potential energy surface (PES) and the consequent decrease in the overall computational effort. The reported surface matches well with the recently published singlet surface by Paukku et al. [J. Chem. Phys. 147, 034301 (2017)]. In addition to the O4 PES, the ground state N4 PES is also constructed using the point generation scheme and compared with the existing PES [Y. Paukku et al., J. Chem. Phys. 139, 044309 (2013)]. The singlet surface is constructed with the aim of studying high energy O2-O2 collisions and predicting collision induced dissociation cross section to be used in simulating non-equilibrium aerothermodynamic flows.

  18. Pure and Oxidized Copper Materials as Potential Antimicrobial Surfaces for Spaceflight Activities

    Science.gov (United States)

    Hahn, C.; Hans, M.; Hein, C.; Mancinelli, R. L.; Mücklich, F.; Wirth, R.; Rettberg, P.; Hellweg, C. E.; Moeller, R.

    2017-12-01

    Microbial biofilms can lead to persistent infections and degrade a variety of materials, and they are notorious for their persistence and resistance to eradication. During long-duration space missions, microbial biofilms present a danger to crew health and spacecraft integrity. The use of antimicrobial surfaces provides an alternative strategy for inhibiting microbial growth and biofilm formation to conventional cleaning procedures and the use of disinfectants. Antimicrobial surfaces contain organic or inorganic compounds, such as antimicrobial peptides or copper and silver, that inhibit microbial growth. The efficacy of wetted oxidized copper layers and pure copper surfaces as antimicrobial agents was tested by applying cultures of Escherichia coli and Staphylococcus cohnii to these metallic surfaces. Stainless steel surfaces were used as non-inhibitory control surfaces. The production of reactive oxygen species and membrane damage increased rapidly within 1 h of exposure on pure copper surfaces, but the effect on cell survival was negligible even after 2 h of exposure. However, longer exposure times of up to 4 h led to a rapid decrease in cell survival, whereby the survival of cells was additionally dependent on the exposed cell density. Finally, the release of metal ions was determined to identify a possible correlation between copper ions in suspension and cell survival. These measurements indicated a steady increase of free copper ions, which were released indirectly by cells presumably through excreted complexing agents. These data indicate that the application of antimicrobial surfaces in spaceflight facilities could improve crew health and mitigate material damage caused by microbial contamination and biofilm formation. Furthermore, the results of this study indicate that cuprous oxide layers were superior to pure copper surfaces related to the antimicrobial effect and that cell density is a significant factor that influences the time dependence of

  19. Two-dimensional potential and charge distributions of positive surface streamer

    International Nuclear Information System (INIS)

    Tanaka, Daiki; Matsuoka, Shigeyasu; Kumada, Akiko; Hidaka, Kunihiko

    2009-01-01

    Information on the potential and the field profile along a surface discharge is required for quantitatively discussing and clarifying the propagation mechanism. The sensing technique with a Pockels crystal has been developed for directly measuring the potential and electric field distribution on a dielectric material. In this paper, the Pockels sensing system consists of a pulse laser and a CCD camera for measuring the instantaneous two-dimensional potential distribution on a 25.4 mm square area with a 50 μm sampling pitch. The temporal resolution is 3.2 ns which is determined by the pulse width of the laser emission. The transient change in the potential distribution of a positive surface streamer propagating in atmospheric air is measured with this system. The electric field and the charge distributions are also calculated from the measured potential profile. The propagating direction component of the electric field near the tip of the propagating streamer reaches 3 kV mm -1 . When the streamer stops, the potential distribution along a streamer forms an almost linear profile with the distance from the electrode, and its gradient is about 0.5 kV mm -1 .

  20. Critical insight into the influence of the potential energy surface on fission dynamics

    International Nuclear Information System (INIS)

    Mazurek, K.; Schmitt, C.; Wieleczko, J. P.; Ademard, G.; Nadtochy, P. N.

    2011-01-01

    The present work is dedicated to a careful investigation of the influence of the potential energy surface on the fission process. The time evolution of nuclei at high excitation energy and angular momentum is studied by means of three-dimensional Langevin calculations performed for two different parametrizations of the macroscopic potential: the Finite Range Liquid Drop Model (FRLDM) and the Lublin-Strasbourg Drop (LSD) prescription. Depending on the mass of the system, the topology of the potential throughout the deformation space of interest in fission is observed to noticeably differ within these two approaches, due to the treatment of curvature effects. When utilized in the dynamical calculation as the driving potential, the FRLDM and LSD models yield similar results in the heavy-mass region, whereas the predictions can be strongly dependent on the Potential Energy Surface (PES) for medium-mass nuclei. In particular, the mass, charge, and total kinetic energy distributions of the fission fragments are found to be narrower with the LSD prescription. The influence of critical model parameters on our findings is carefully investigated. The present study sheds light on the experimental conditions and signatures well suited for constraining the parametrization of the macroscopic potential. Its implication regarding the interpretation of available experimental data is briefly discussed.

  1. Atom diffraction reveals the impact of atomic core electrons on atom-surface potentials.

    Science.gov (United States)

    Lonij, Vincent P A; Klauss, Catherine E; Holmgren, William F; Cronin, Alexander D

    2010-12-03

    We measured ratios of van der Waals potential coefficients (C3) for different atoms (Li, Na, K, and Rb) interacting with the same surface by studying atom diffraction from a nanograting. These measurements are a sensitive test of atomic structure calculations because C3 ratios are strongly influenced by core electrons and only weakly influenced by the permittivity and geometry of the surface. Our measurement uncertainty of 2% in the ratio C(3)(K)/C(3)(Na) is close to the uncertainty of the best theoretical predictions, and some of these predictions are inconsistent with our measurement.

  2. On the instabilities of a potential vortex with a free surface

    DEFF Research Database (Denmark)

    Mougel, J.; Fabre, D.; Lacaze, L.

    2017-01-01

    In this paper, we address the linear stability analysis of a confined potential vortex with a free surface. This particular flow has been recently used by Tophoj et al. (Phys. Rev. Lett., vol. 110(19), 2013, article 194502) as a model for the swirling flow of fluid in an open cylindrical containe...... the numerical and theoretical analysis presented. These different methods and observations allow to support the unstable wave coupling mechanism as the physical process at the origin of the polygonal patterns observed in free-surface rotating flows....

  3. Potential energy surfaces for N = Z, 20Ne-112Ba nuclei

    International Nuclear Information System (INIS)

    Mehta, M.S.; Gupta, Raj K.; Jha, T.K.; Patra, S.K.

    2004-01-01

    We have calculated the potential energy surfaces for N = Z, 20 Ne- 112 Ba nuclei in an axially deformed relativistic mean field approach. A quadratic constraint scheme is applied to determine the complete energy surface for a wide range of the quadrupole deformation. The NL3, NL-RAl and TM1 parameter sets are used. The phenomenon of (multiple) shape coexistence is studied and the calculated ground and excited state binding energies, quadrupole deformation parameters and root mean square (rms) charge radii are compared with the available experimental data and other theoretical predictions. (author)

  4. Increased urinary lysophosphatidic acid in mouse with subtotal nephrectomy: potential involvement in chronic kidney disease.

    Science.gov (United States)

    Mirzoyan, Koryun; Baïotto, Anna; Dupuy, Aude; Marsal, Dimitri; Denis, Colette; Vinel, Claire; Sicard, Pierre; Bertrand-Michel, Justine; Bascands, Jean-Loup; Schanstra, Joost P; Klein, Julie; Saulnier-Blache, Jean-Sébastien

    2016-12-01

    Increased incidence of chronic kidney disease (CKD) with consecutive progression to end-stage renal disease represents a significant burden to healthcare systems. Renal tubulointerstitial fibrosis (TIF) is a classical hallmark of CKD and is well correlated with the loss of renal function. The bioactive lysophospholipid lysophosphatidic acid (LPA), acting through specific G-protein-coupled receptors, was previously shown to be involved in TIF development in a mouse model of unilateral ureteral obstruction. Here, we study the role of LPA in a mouse subjected to subtotal nephrectomy (SNx), a more chronic and progressive model of CKD. Five months after surgical nephron reduction, SNx mice showed massive albuminuria, extensive TIF, and glomerular hypertrophy when compared to sham-operated animals. Urinary and plasma levels of LPA were analyzed using liquid chromatography tandem mass spectrometry. LPA was significantly increased in SNx urine, not in plasma, and was significantly correlated with albuminuria and TIF. Moreover, SNx mice showed significant downregulation in the renal expression of lipid phosphate phosphohydrolases (LPP1, 2, and 3) that might be involved in reduced LPA bioavailability through dephosphorylation. We concluded that SNx increases urinary LPA through a mechanism that could involve co-excretion of plasma LPA with albumin associated with a reduction of its catabolism in the kidney. Because of the previously demonstrated profibrotic activity of LPA, the association of urinary LPA with TIF suggests the potential involvement of LPA in the development of advanced CKD in the SNx mouse model. Targeting LPA metabolism might represent an interesting approach in CKD treatment.

  5. Feet on the potential energy surface, head in the pi clouds

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Quentin [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    This work presents explorations of the potential energy surface of clusters of atoms and of the interactions between molecules. First, structures of small aluminum clusters are examined and classified as ground states, transition states, or higher-order saddle points. Subsequently, the focus shifts to dispersion-dominated π-π interactions when the potential energy surfaces of benzene, substituted benzene, and pyridine dimers are explored. Because DNA nucleotide bases can be thought of as substituted heterocycles, a natural extension of the substituted benzene and pyridine investigations is to model paired nucleotide bases. Finally, the success of the dispersion studies inspires the development of an extension to the computational method used, which will enable the dispersion energy to be modeled – and the potential energy surface explored – in additional chemical systems. The effective fragment potential (EFP) method is described, as well as various quantum mechanical methods. An ab inito quantum mechanical study of 13-atom aluminum clusters is described. EFP studies of aromatic dimers are reported in which dispersion energy makes a significant contribution to the attraction between monomers. Theory and code development toward a means of computing dispersion energy in mixed ab inito-EFP systems are described.

  6. Potential energy surfaces for alkali plus noble gas pairs: a systematic comparison

    Science.gov (United States)

    Blank, L. Aaron; Kedziora, Gary S.; Weeks, David E.

    2010-02-01

    Optically Pumped Alkali Lasers (OPAL) involve interactions of alkali atoms with a buffer gas typically consisting of a noble gas together with C2H4. Line broadening mechanisms are of particular interest because they can be used to match a broad optical pumping source with relatively narrow alkali absorption spectra. To better understand the line broadening processes at work in OPAL systems we focus on the noble gas collisional partners. A matrix of potential energy surfaces (PES) has been generated at the multi-configurational self consistent field (MCSCF) level for M + Ng, where M=Li, Na, K, Rb, Cs and Ng=He, Ne, Ar. The PES include the X2Σ ground state surface and the A2II, B2Σ excited state surfaces. In addition to the MCSCF surfaces, PES for Li+He have been calculated at the multi-reference singles and doubles configuration interaction (MRSDCI) level with spin-orbit splitting effects included. These surfaces provide a way to check the qualitative applicability of the MCSCF calculations. They also exhibit the avoided crossing between the B2Σ and A2II1/2 surfaces that is partially responsible for collision induced relaxation from the 2P3/2 to the 2P1/2 atomic levels.

  7. Bohm potential effect on the propagation of electrostatic surface wave in semi-bounded quantum plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myoung-Jae [Department of Physics, Hanyang University, Seoul 04763 (Korea, Republic of); Research Institute for Natural Sciences, Hanyang University, Seoul 04763 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 15588 (Korea, Republic of); Department of Electrical and Computer Engineering, MC 0407, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0407 (United States)

    2017-02-12

    High frequency electrostatic wave propagation in a dense and semi-bounded electron quantum plasma is investigated with consideration of the Bohm potential. The dispersion relation for the surface mode of quantum plasma is derived and numerically analyzed. We found that the quantum effect enhances the frequency of the wave especially in the high wave number regime. However, the frequency of surface wave is found to be always lower than that of the bulk wave for the same quantum wave number. The group velocity of the surface wave for various quantum wave number is also obtained. - Highlights: • High frequency electrostatic wave propagation is investigated in a dense semi-bounded quantum plasma. • The dispersion relation for the surface mode of quantum plasma is derived and numerically analyzed. • The quantum effect enhances the frequency of the wave especially in the high wave number regime. • The frequency of surface wave is found to be always lower than that of the bulk wave. • The group velocity of the surface wave for various quantum wave number is also obtained.

  8. Increase in post activation potentiation in females following a cycling warmup.

    Science.gov (United States)

    Simpson, Carey L; Flatman, Marina M; Kim, Brian D H; Bouwmeester, Nikita M; Jakobi, Jennifer M

    2018-02-01

    Post activation potentiation (PAP) is a phenomenon in which muscular force is acutely enhanced as a result of prior contractile activity. The net augmentation is dependent upon the intensity of the preceding conditioning contraction influencing calcium release and phosphorylation of the regulatory myosin light chain. This phenomenon has been recorded after various types of conditioning contractions, however the interaction of a warmup on PAP remains uncertain and whether this differs between males and females requires consideration. We investigated the effect of a cycling warmup on twitch contractile properties and PAP of the plantar flexors on males and in females using oral contraceptives. A maximal voluntary contraction (MVC) of the plantar flexors preceded and followed a 10-min cycling warmup, where supramaximal twitches were administered prior to, during and after the conditioning contractions. Twitch contractile properties of peak tension (PT), time to peak tension (TPT), half relaxation time (HRT) and contraction duration (CD) were compared between resting and potentiated twitches before and after the warmup. Ultrasonography was used to measure in vivo Achilles tendon architecture. Males were ∼30% stronger, but voluntary activation did not differ from females (p = .37). In males and females PT increased following the conditioning MVC (p = .03). The degree of potentiation was higher following the warmup in females (25.01%, p = .02) but not males (p = .24). TPT, HRT and contraction duration (p minutes of a cycling warmup reduced TPT, HRT, and CD in both males and females without altering the tendon. The degree of PAP was higher in females than males following the warmup. This difference might be associated with altered calcium kinetics of females on oral contraceptives as well as higher proportion of type I fibres in the active muscles. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Bilingualism and increased attention to speech: Evidence from event-related potentials.

    Science.gov (United States)

    Kuipers, Jan Rouke; Thierry, Guillaume

    2015-10-01

    A number of studies have shown that from an early age, bilinguals outperform their monolingual peers on executive control tasks. We previously found that bilingual children and adults also display greater attention to unexpected language switches within speech. Here, we investigated the effect of a bilingual upbringing on speech perception in one language. We recorded monolingual and bilingual toddlers' event-related potentials (ERPs) to spoken words preceded by pictures. Words matching the picture prime elicited an early frontal positivity in bilingual participants only, whereas later ERP amplitudes associated with semantic processing did not differ between groups. These results add to the growing body of evidence that bilingualism increases overall attention during speech perception whilst semantic integration is unaffected. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Adsorption of urinary components influences the zeta potential of uropathogen surfaces

    NARCIS (Netherlands)

    Habash, MB; van der Mei, HC; Busscher, HJ; Reid, G

    2000-01-01

    Zeta potential distributions of five uropathogens were measured in urines collected after increased water intake, consumption of cranberry supplements, or intake of ascorbic acid by volunteers. Zeta potentials of bacteria in urine from ascorbic acid consumption shifted towards less negative values

  11. Two decades of warming increases diversity of a potentially lignolytic bacterial community.

    Science.gov (United States)

    Pold, Grace; Melillo, Jerry M; DeAngelis, Kristen M

    2015-01-01

    As Earth's climate warms, the massive stores of carbon found in soil are predicted to become depleted, and leave behind a smaller carbon pool that is less accessible to microbes. At a long-term forest soil-warming experiment in central Massachusetts, soil respiration and bacterial diversity have increased, while fungal biomass and microbially-accessible soil carbon have decreased. Here, we evaluate how warming has affected the microbial community's capability to degrade chemically-complex soil carbon using lignin-amended BioSep beads. We profiled the bacterial and fungal communities using PCR-based methods and completed extracellular enzyme assays as a proxy for potential community function. We found that lignin-amended beads selected for a distinct community containing bacterial taxa closely related to known lignin degraders, as well as members of many genera not previously noted as capable of degrading lignin. Warming tended to drive bacterial community structure more strongly in the lignin beads, while the effect on the fungal community was limited to unamended beads. Of those bacterial operational taxonomic units (OTUs) enriched by the warming treatment, many were enriched uniquely on lignin-amended beads. These taxa may be contributing to enhanced soil respiration under warming despite reduced readily available C availability. In aggregate, these results suggest that there is genetic potential for chemically complex soil carbon degradation that may lead to extended elevated soil respiration with long-term warming.

  12. Challenges in testing genetically modified crops for potential increases in endogenous allergen expression for safety.

    Science.gov (United States)

    Panda, R; Ariyarathna, H; Amnuaycheewa, P; Tetteh, A; Pramod, S N; Taylor, S L; Ballmer-Weber, B K; Goodman, R E

    2013-02-01

    Premarket, genetically modified (GM) plants are assessed for potential risks of food allergy. The major risk would be transfer of a gene encoding an allergen or protein nearly identical to an allergen into a different food source, which can be assessed by specific serum testing. The potential that a newly expressed protein might become an allergen is evaluated based on resistance to digestion in pepsin and abundance in food fractions. If the modified plant is a common allergenic source (e.g. soybean), regulatory guidelines suggest testing for increases in the expression of endogenous allergens. Some regulators request evaluating endogenous allergens for rarely allergenic plants (e.g. maize and rice). Since allergic individuals must avoid foods containing their allergen (e.g. peanut, soybean, maize, or rice), the relevance of the tests is unclear. Furthermore, no acceptance criteria are established and little is known about the natural variation in allergen concentrations in these crops. Our results demonstrate a 15-fold difference in the major maize allergen, lipid transfer protein between nine varieties, and complex variation in IgE binding to various soybean varieties. We question the value of evaluating endogenous allergens in GM plants unless the intent of the modification was production of a hypoallergenic crop. © 2012 John Wiley & Sons A/S.

  13. Reduced cortical thickness and increased surface area in antisocial personality disorder.

    Science.gov (United States)

    Jiang, Weixiong; Li, Gang; Liu, Huasheng; Shi, Feng; Wang, Tao; Shen, Celina; Shen, Hui; Lee, Seong-Whan; Hu, Dewen; Wang, Wei; Shen, Dinggang

    2016-11-19

    Antisocial personality disorder (ASPD), one of whose characteristics is high impulsivity, is of great interest in the field of brain structure and function. However, little is known about possible impairments in the cortical anatomy in ASPD, in terms of cortical thickness (CTh) and surface area (SA), as well as their possible relationship with impulsivity. In this neuroimaging study, we first investigated the changes of CTh and SA in ASPD patients, in comparison to those of healthy controls, and then performed correlation analyses between these measures and the ability of impulse control. We found that ASPD patients showed thinner cortex while larger SA in several specific brain regions, i.e., bilateral superior frontal gyrus (SFG), orbitofrontal and triangularis, insula cortex, precuneus, middle frontal gyrus (MFG), middle temporal gyrus (MTG), and left bank of superior temporal sulcus (STS). In addition, we also found that the ability of impulse control was positively correlated with CTh in the SFG, MFG, orbitofrontal cortex (OFC), pars triangularis, superior temporal gyrus (STG), and insula cortex. To our knowledge, this study is the first to reveal simultaneous changes in CTh and SA in ASPD, as well as their relationship with impulsivity. These cortical structural changes may introduce uncontrolled and callous behavioral characteristic in ASPD patients, and these potential biomarkers may be very helpful in understanding the pathomechanism of ASPD. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  14. Increased parasite surface antigen-2 expression in clinical isolates of Leishmania donovani augments antimony resistance.

    Science.gov (United States)

    Bhandari, Vasundhra; Kumar, Dhiraj; Verma, Sandeep; Srividya, Gurumurthy; Negi, Narendra Singh; Singh, Ruchi; Salotra, Poonam

    2013-11-01

    Resistance to sodium antimony gluconate (SAG) is a major cause of therapeutic failure in a large proportion of visceral leishmaniasis (VL) cases. Determinants of SAG resistance have been widely studied; however, the mechanism operating in clinical isolates is poorly understood. In the present study, expression of parasite surface antigen-2 (PSA-2) gene was studied in clinical isolates of Leishmania donovani comprising of antimony resistant (n=10) and sensitive (n=4) parasites. The expression of PSA-2 gene was found to be consistently high in SAG resistant clinical isolates (≥1.5-fold) at both transcript and protein level. Further, over-expression of PSA-2 in L. donovani isolates (LdPSA-2(++)) resulted in conversion of SAG sensitive phenotype to resistant. The LdPSA-2(++) parasites showed significantly decreased susceptibility towards SAG (>12-fold), amphotericin B (>4-fold) and miltefosine (>2.5-fold). Marked decrease in antimony accumulation and enhanced tolerance towards complement mediated lysis was evident in LdPSA-2(++) parasites. The study established the role of PSA-2 gene in SAG resistance and its potential as a biomarker to distinguish resistant and sensitive clinical isolates of L. donovani. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Effects of external surface charges on the enhanced piezoelectric potential of ZnO and AlN nanowires and nanotubes

    Directory of Open Access Journals (Sweden)

    Seong Min Kim

    2012-12-01

    Full Text Available We theoretically investigate external surface charge effects on piezoelectric potential of ZnO and AlN nanowires (NWs and nanotubes (NTs under uniform compression. The free carrier depletion caused by negative surface charges via surface functionalization on vertically compressed ZnO and AlN NWs/NTs is simulated using finite element calculation; this indicates the enhancement of piezoelectric potential is due to the free carriers (electrons being fully depleted at the critical surface charge density. Numerical simulations reveal that full coverage of surface charges surrounding the NTs increases the piezoelectric output potential exponentially within a relatively smaller range of charge density compared to the case of NWs for a typical donor concentration (∼1017 cm−3. The model can be used to design functional high-power semiconducting piezoelectric nanogenerators.

  16. Will climate change increase hybridization risk between potential plant invaders and their congeners in Europe?

    Science.gov (United States)

    Klonner, Günther; Dullinger, Iwona; Wessely, Johannes; Bossdorf, Oliver; Carboni, Marta; Dawson, Wayne; Essl, Franz; Gattringer, Andreas; Haeuser, Emily; van Kleunen, Mark; Kreft, Holger; Moser, Dietmar; Pergl, Jan; Pyšek, Petr; Thuiller, Wilfried; Weigelt, Patrick; Winter, Marten; Dullinger, Stefan

    2017-08-01

    Interspecific hybridization can promote invasiveness of alien species. In many regions of the world, public and domestic gardens contain a huge pool of non-native plants. Climate change may relax constraints on their naturalization and hence facilitate hybridization with related species in the resident flora. Here, we evaluate this possible increase in hybridization risk by predicting changes in the overlap of climatically suitable ranges between a set of garden plants and their congeners in the resident flora. Europe. From the pool of alien garden plants, we selected those which (1) are not naturalized in Europe, but established outside their native range elsewhere in the world; (2) belong to a genus where interspecific hybridization has been previously reported; and (3) have congeners in the native and naturalized flora of Europe. For the resulting set of 34 alien ornamentals as well as for 173 of their European congeners, we fitted species distribution models and projected suitable ranges under the current climate and three future climate scenarios. Changes in range overlap between garden plants and congeners were then assessed by means of the true skill statistic. Projections suggest that under a warming climate, suitable ranges of garden plants will increase, on average, while those of their congeners will remain constant or shrink, at least under the more severe climate scenarios. The mean overlap in ranges among congeners of the two groups will decrease. Variation among genera is pronounced; however, and for some congeners, range overlap is predicted to increase significantly. Averaged across all modelled species, our results do not indicate that hybrids between potential future invaders and resident species will emerge more frequently in Europe when climate warms. These average trends do not preclude, however, that hybridization risk may considerably increase in particular genera.

  17. Electrical potential-assisted DNA hybridization. How to mitigate electrostatics for surface DNA hybridization.

    Science.gov (United States)

    Tymoczko, Jakub; Schuhmann, Wolfgang; Gebala, Magdalena

    2014-12-24

    Surface-confined DNA hybridization reactions are sensitive to the number and identity of DNA capture probes and experimental conditions such as the nature and the ionic strength of the electrolyte solution. When the surface probe density is high or the concentration of bulk ions is much lower than the concentration of ions within the DNA layer, hybridization is significantly slowed down or does not proceed at all. However, high-density DNA monolayers are attractive for designing high-sensitivity DNA sensors. Thus, circumventing sluggish DNA hybridization on such interfaces allows a high surface concentration of target DNA and improved signal/noise ratio. We present potential-assisted hybridization as a strategy in which an external voltage is applied to the ssDNA-modified interface during the hybridization process. Results show that a significant enhancement of hybridization can be achieved using this approach.

  18. Potentialities of some surface characterization techniques for the development of titanium biomedical alloys

    Directory of Open Access Journals (Sweden)

    P.S. Vanzillotta

    2004-09-01

    Full Text Available Bone formation around a metallic implant is a complex process that involves micro- and nanometric interactions. Several surface treatments, including coatings were developed in order to obtain faster osseointegration. To understand the role of these surface treatments on bone formation it is necessary to choose adequate characterization techniques. Among them, we have selected electron microscopy, profilometry, atomic force microscopy (AFM and X-ray photoelectron spectroscopy (XPS to describe them briefly. Examples of the potentialities of these techniques on the characterization of titanium for biomedical applications were also presented and discussed. Unfortunately more than one technique is usually necessary to describe conveniently the topography (scanning electron microsocopy, profilometry and/or AFM and the chemical state (XPS of the external layer of the material surface. The employment of the techniques above described can be useful especially for the development of new materials or products.

  19. Metrological Aspects of Surface Topographies Produced by Different Machining Operations Regarding Their Potential Functionality

    Directory of Open Access Journals (Sweden)

    Żak Krzysztof

    2017-06-01

    Full Text Available This paper presents a comprehensive methodology for measuring and characterizing the surface topographies on machined steel parts produced by precision machining operations. The performed case studies concern a wide spectrum of topographic features of surfaces with different geometrical structures but the same values of the arithmetic mean height Sa. The tested machining operations included hard turning operations performed with CBN tools, grinding operations with Al2O3 ceramic and CBN wheels and superfinish using ceramic stones. As a result, several characteristic surface textures with the Sa roughness parameter value of about 0.2 μm were thoroughly characterized and compared regarding their potential functional capabilities. Apart from the standard 2D and 3D roughness parameters, the fractal, motif and frequency parameters were taken in the consideration.

  20. Stair-Step Particle Flux Spectra on the Lunar Surface: Evidence for Nonmonotonic Potentials?

    Science.gov (United States)

    Collier, Michael R.; Newheart, Anastasia; Poppe, Andrew R.; Hills, H. Kent; Farrell, William M.

    2016-01-01

    We present examples of unusual "stair-step" differential flux spectra observed by the Apollo 14 Suprathermal Ion Detector Experiment on the lunar dayside surface in Earth's magnetotail. These spectra exhibit a relatively constant differential flux below some cutoff energy and then drop off precipitously, by about an order of magnitude or more, at higher energies. We propose that these spectra result from photoions accelerated on the lunar dayside by nonmonotonic potentials (i.e.,potentials that do not decay to zero monotonically) and present a model for the expected differential flux. The energy of the cutoff and the magnitude of the differential flux are related to the properties of the local space environment and are consistent with the observed flux spectra. If this interpretation is correct, these surface-based ion observations provide a unique perspective that both complements and enhances the conclusions obtained by remote-sensing orbiter observations on the Moon's exospheric and electrostatic properties.

  1. Prediction of Tetraoxygen Reaction Mechanism with Sulfur Atom on the Singlet Potential Energy Surface

    Directory of Open Access Journals (Sweden)

    Ashraf Khademzadeh

    2014-01-01

    Full Text Available The mechanism of S+O4 (D2h reaction has been investigated at the B3LYP/6-311+G(3df and CCSD levels on the singlet potential energy surface. One stable complex has been found for the S+O4 (D2h reaction, IN1, on the singlet potential energy surface. For the title reaction, we obtained four kinds of products at the B3LYP level, which have enough thermodynamic stability. The results reveal that the product P3 is spontaneous and exothermic with −188.042 and −179.147 kcal/mol in Gibbs free energy and enthalpy of reaction, respectively. Because P1 adduct is produced after passing two low energy level transition states, kinetically, it is the most favorable adduct in the 1S+1O4 (D2h atmospheric reactions.

  2. Systematic and efficient navigating potential energy surface: Data for silver doped gold clusters

    Directory of Open Access Journals (Sweden)

    Vitaly V. Chaban

    2016-06-01

    Full Text Available Locating global minimum of certain atomistic ensemble is known to be a highly challenging and resource consuming task. This dataset represents joint usage of the semi-empirical PM7 Hamiltonian, Broyden–Fletcher–Goldfarb–Shanno algorithm and basin hopping scheme to navigate a potential energy surface. The Au20 nanocluster was used for calibration as its global minimum structure is well-known. Furthermore, Au18Ag2 and Au15Ag5 were simulated for illustration of the algorithm performance. The work shows encouraging results and, particularly, underlines proper accuracy of PM7 as applied to this type of heavy metal systems. The reported dataset motivates to use the benchmarked method for studying potential energy surfaces of manifold systems and locate their global-minimum atomistic configurations.

  3. Dynamical image potential and induced forces for charged particles moving parallel to a solid surface

    International Nuclear Information System (INIS)

    Arista, N.R.

    1994-01-01

    The dynamical image potential and ensuing forces induced by a charged particle moving parallel to a solid surface are investigated by using a dielectric formulation for semi-infinite dispersive media. The adiabatic behavior of the field in the asymptotic range is discussed in a general way using a multipole expansion. Several calculations illustrate the behavior of the field using both a simple model, where the surface response is approximated by a single plasma resonance, and a more realistic representation of the medium based upon the empirical information on the optical constants for various solids (Al, Cu, Ag, and Au). The model parameters may be adjusted to provide very good agreement with the optical-data integrations of the stopping and lateral forces on the moving charge. On the other hand, important differences in the description of the wake potential using either the simple plasma resonance model, or the optical-data representation, are obtained for Cu, Ag, and Au

  4. Modification of transition's factor in the compact surface-potential-based MOSFET model

    Directory of Open Access Journals (Sweden)

    Kevkić Tijana

    2016-01-01

    Full Text Available The modification of an important transition's factor which enables continual behavior of the surface potential in entire useful range of MOSFET operation is presented. The various modifications have been made in order to obtain an accurate and computationally efficient compact MOSFET model. The best results have been achieved by introducing the generalized logistic function (GL in fitting of considered factor. The smoothness and speed of the transition of the surface potential from the depletion to the strong inversion region can be controlled in this way. The results of the explicit model with this GL functional form for transition's factor have been verified extensively with the numerical data. A great agreement was found for a wide range of substrate doping and oxide thickness. Moreover, the proposed approach can be also applied on the case where quantum mechanical effects play important role in inversion mode.

  5. Evaluation of the immunodiagnostic potential of a recombinant surface protein domain from Acanthamoeba castellanii.

    Science.gov (United States)

    Sánchez, Alemao G Carpinteyro; Virginio, Veridiana Gomes; Maschio, Vinicius José; Ferreira, Henrique Bunselmeyer; Rott, Marilise Brittes

    2016-10-01

    Acanthamoeba spp. are free-living protists widely distributed in environment, able to cause keratitis, encephalitis and skin lesions in humans and animals. Acanthamoeba spp. exist in two forms: an infective trophozoite and a dormant cyst. Several factors contribute to the pathogenesis of Acanthamoeba spp. The parasite adhesion to the host cell is the primary step for infection and is mediated by a mannose binding-protein, expressed in the surface and considered the main pathogenicity factor in Acanthamoeba spp. So far, there was no evidence of another surface protein of Acanthamoeba spp. relevant for host invasion or infection by these organisms. The aims of this study were to identify and characterize an Acanthamoeba castellanii surface protein and to evaluate its diagnostic potential. In silico predictions of surface proteins allowed to identify the A. castellanii calreticulin as a possible surface antigen. The coding sequence of a predicted extracellular domain of A. castellanii calreticulin was cloned by in vivo homologous recombination and the recombinant polypeptide (AcCRT29-130) was produced. Its immunodiagnostic potential was assessed in a recombinant antigen-based ELISA with sera from experimentally infected rats that developed keratitis and encephalitis, and sera from patients with encephalitis. The AcCRT29-130 was significantly more recognized by sera from encephalitis infected rats in comparison with the non-infected controls. Human sera from encephalitis patients, however presented no significant response. These results showed the AcCRT29-130 potential for A. castellanii infection immunodiagnosis in animals, with further studies being required for assessment of its use for human infections.

  6. Exploring a potential energy surface by machine learning for characterizing atomic transport

    Science.gov (United States)

    Kanamori, Kenta; Toyoura, Kazuaki; Honda, Junya; Hattori, Kazuki; Seko, Atsuto; Karasuyama, Masayuki; Shitara, Kazuki; Shiga, Motoki; Kuwabara, Akihide; Takeuchi, Ichiro

    2018-03-01

    We propose a machine-learning method for evaluating the potential barrier governing atomic transport based on the preferential selection of dominant points for atomic transport. The proposed method generates numerous random samples of the entire potential energy surface (PES) from a probabilistic Gaussian process model of the PES, which enables defining the likelihood of the dominant points. The robustness and efficiency of the method are demonstrated on a dozen model cases for proton diffusion in oxides, in comparison with a conventional nudge elastic band method.

  7. Physisorbed H{sub 2}@Cu(100) surface: Potential and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Eddy; Houriez, Céline; Mitrushchenkov, Alexander O.; Guitou, Marie; Chambaud, Gilberte, E-mail: gilberte.chambaud@univ-mlv.fr [Université Paris-Est, Laboratoire Modélisation et Simulation Multi-Echelle, UMR 8208 CNRS, 5 Boulevard Descartes, Champs sur Marne, F-77454 Marne-la-Vallée (France)

    2015-02-07

    Using an embedding approach, a 2-D potential energy function has been calculated to describe the physisorption interaction of H{sub 2} with a Cu(100) surface. For this purpose, a cluster model of the system calculated with highly correlated wavefunctions is combined with a periodic Density-Functional-Theory method using van der Waals-DF2 functional. Rotational and vibrational energy levels of physisorbed H{sub 2}, as well as D{sub 2} and HD, are calculated using the 2D embedding corrected potential energy function. The calculated transitions are in a very good agreement with Electron-Energy-Loss-Spectroscopy observations.

  8. The potential sensitivity of tropical plants to increased ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Ziska, L.H.

    1996-01-01

    Little is known concerning the impact of stratospheric ozone depletion and increasing ultraviolet (UV)-B radiation on the phenology and growth of tropical plants. This is because, ostensibly, tropical plants are already exposed to relatively high levels of UV-B radiation (relative to a temperate environment) and should, therefore, possess a greater degree of tolerance to increased UV-B radiation. In this brief review I hope to show that, potentially, direct and indirect effects on photosynthesis, assimilate partitioning, phenology and biomass could occur in both tropical crops (e.g. cassava, rice) and native species (e.g. Cecropia obtusifolia (Bertol. Fl)., Tetramolopium humile (Gray), Nana sandwicensis L.). However, it should be noted that differences in sensitivity to UV-B radiation can be related to experimental conditions, and care should be taken to ensure that the quantity and quality of background solar radiation remains at near ambient conditions. Nevertheless, by integrating current and past studies on the impact of UV-B radiation on tropical species, I hope to be able to demonstrate that photosynthesis, morphology and growth in tropical plants could be directly affected by UV-B radiation and that UV-B radiation may be a factor in species and community dynamics in natural plant populations in the tropics

  9. Rotational Energy Transfer of N2 Gas Determined Using a New Ab Initio Potential Energy Surface

    Science.gov (United States)

    Huo, Winifred M.; Stallcop, James R.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    Rotational energy transfer between two N2 molecules is a fundamental process of some importance. Exchange is expected to play a role, but its importance is somewhat uncertain. Rotational energy transfer cross sections of N2 also have applications in many other fields including modeling of aerodynamic flows, laser operations, and linewidth analysis in nonintrusive laser diagnostics. A number of N2-N2 rigid rotor potential energy surface (PES) has been reported in the literature.

  10. Climate change impact of livestock CH4emission in India: Global temperature change potential (GTP) and surface temperature response.

    Science.gov (United States)

    Kumari, Shilpi; Hiloidhari, Moonmoon; Kumari, Nisha; Naik, S N; Dahiya, R P

    2018-01-01

    Two climate metrics, Global surface Temperature Change Potential (GTP) and the Absolute GTP (AGTP) are used for studying the global surface temperature impact of CH 4 emission from livestock in India. The impact on global surface temperature is estimated for 20 and 100 year time frames due to CH 4 emission. The results show that the CH 4 emission from livestock, worked out to 15.3 Tg in 2012. In terms of climate metrics GTP of livestock-related CH 4 emission in India in 2012 were 1030 Tg CO 2 e (GTP 20 ) and 62 Tg CO 2 e (GTP 100 ) at the 20 and 100 year time horizon, respectively. The study also illustrates that livestock-related CH 4 emissions in India can cause a surface temperature increase of up to 0.7mK and 0.036mK over the 20 and 100 year time periods, respectively. The surface temperature response to a year of Indian livestock emission peaks at 0.9mK in the year 2021 (9 years after the time of emission). The AGTP gives important information in terms of temperature change due to annual CH 4 emissions, which is useful when comparing policies that address multiple gases. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. The potential role of omega-3 fatty acids supplements in increasing athletic performance

    Directory of Open Access Journals (Sweden)

    Șerban GLIGOR

    2017-03-01

    Full Text Available Polyunsaturated omega-3 and omega-6 fatty acids are essential fatty acids that cannot be produced by the body itself and therefore must be provided through nutrition. Omega-6 and particularly omega-3 fatty acids have important roles in the organism, contributing to the maintenance and promotion of health. The optimal proportion of omega-6/omega-3 fatty acids is 2:1, or even better 1:1. They are involved in normal growth and development, play a role in the prevention of coronary and cardiovascular diseases, of diabetes mellitus, of arterial hypertension, arthritis and cancer. Omega-3 fatty acids mainly have an anti-inflammatory effect, but also act as hypolipidemic and antithrombotic agents. A potential role of omega-3 fatty acids is that of increasing physical performance. Their role in the physical activity refers on one side to the global health of athletes and on the other side to their anti-inflammatory effect, as high intensity physical exercise induces increased free-radical production and microtraumas, with the induction of an inflammatory status. The anti-inflammatory effect of these fatty acids manifests through an increased production of endogenous antioxidant enzymes, through decreasing the production of prostaglandins metabolites, decreasing the production of leukotriene B4, etc. They are also effective on reducing muscle pain post eccentric exercise and on decreasing the severity of bronchoconstriction induced by exercise, as well as improving pulmonary function variables. In conclusion it seems that supplementing diets with omega-3 fatty acids, apart from having benefic effects on health and on the prevention and management of certain affections, proves to be a beneficial for physical activity and athletic performance.

  12. Computed Potential Energy Surfaces and Minimum Energy Pathways for Chemical Reactions

    Science.gov (United States)

    Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

    1994-01-01

    Computed potential energy surfaces are often required for computation of such parameters as rate constants as a function of temperature, product branching ratios, and other detailed properties. For some dynamics methods, global potential energy surfaces are required. In this case, it is necessary to obtain the energy at a complete sampling of all the possible arrangements of the nuclei, which are energetically accessible, and then a fitting function must be obtained to interpolate between the computed points. In other cases, characterization of the stationary points and the reaction pathway connecting them is sufficient. These properties may be readily obtained using analytical derivative methods. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method to obtain accurate energetics, gives usefull results for a number of chemically important systems. The talk will focus on a number of applications including global potential energy surfaces, H + O2, H + N2, O(3p) + H2, and reaction pathways for complex reactions, including reactions leading to NO and soot formation in hydrocarbon combustion.

  13. The potential of shifting recombination hotspots to increase genetic gain in livestock breeding.

    Science.gov (United States)

    Gonen, Serap; Battagin, Mara; Johnston, Susan E; Gorjanc, Gregor; Hickey, John M

    2017-07-04

    This study uses simulation to explore and quantify the potential effect of shifting recombination hotspots on genetic gain in livestock breeding programs. We simulated three scenarios that differed in the locations of quantitative trait nucleotides (QTN) and recombination hotspots in the genome. In scenario 1, QTN were randomly distributed along the chromosomes and recombination was restricted to occur within specific genomic regions (i.e. recombination hotspots). In the other two scenarios, both QTN and recombination hotspots were located in specific regions, but differed in whether the QTN occurred outside of (scenario 2) or inside (scenario 3) recombination hotspots. We split each chromosome into 250, 500 or 1000 regions per chromosome of which 10% were recombination hotspots and/or contained QTN. The breeding program was run for 21 generations of selection, after which recombination hotspot regions were kept the same or were shifted to adjacent regions for a further 80 generations of selection. We evaluated the effect of shifting recombination hotspots on genetic gain, genetic variance and genic variance. Our results show that shifting recombination hotspots reduced the decline of genetic and genic variance by releasing standing allelic variation in the form of new allele combinations. This in turn resulted in larger increases in genetic gain. However, the benefit of shifting recombination hotspots for increased genetic gain was only observed when QTN were initially outside recombination hotspots. If QTN were initially inside recombination hotspots then shifting them decreased genetic gain. Shifting recombination hotspots to regions of the genome where recombination had not occurred for 21 generations of selection (i.e. recombination deserts) released more of the standing allelic variation available in each generation and thus increased genetic gain. However, whether and how much increase in genetic gain was achieved by shifting recombination hotspots depended

  14. Surface potential at the hematite (001) crystal plane in aqueous environments and the effects of prolonged aging in water

    Science.gov (United States)

    Lützenkirchen, Johannes; Preočanin, Tajana; Stipić, Filip; Heberling, Frank; Rosenqvist, Jörgen; Kallay, Nikola

    2013-11-01

    The surface potentials of a (0 0 1) terminated hematite crystal that was annealed at high-temperature were measured as a function of pH by means of the corresponding single crystal electrode. The surface potential at a given pH did not depend on the electrolyte concentration, and was found to exhibit an inflection point. The shape of the function is in phenomenological agreement with the presence of two distinct surface terminations (O and Fe) that have been previously reported for this surface. Aging of the annealed hematite surface, in aqueous electrolyte medium over 2 weeks, leads to a drastic change in the surface potential pH curve. The surface potential becomes that of the ideal O termination. While the O termination data can be modeled using the MUSIC approach, the initial sample that is expected to correspond to the two-domain surface with O and Fe terminations cannot be described within the MUSIC approach based on previously published surface diffraction data. However, the experimental data fall between the O and Fe termination limiting cases when the point of zero potential is placed at the inflection point. The fact that a surface with the two terminations cannot be modeled may be attributed to various issues, three of which are discussed: (i) the general difficulty to average the potential arising from both terminations, which furthermore are short-circuited via the crystal, (ii) the difficulty of treating patchwise heterogeneous surfaces in surface complexation models, and (iii) the incapability of surface complexation models in their present form to describe potential gradients within the solid. Conclusively, we interpret our results as a transformation from a bi-domain surface, to a single domain surface over time under conditions where bulk hematite solubility is low. Accordingly, the oxygen terminated domain should be the more stable one at this single crystal surface at our experimental conditions.

  15. CONSTRAINING THE NFW POTENTIAL WITH OBSERVATIONS AND MODELING OF LOW SURFACE BRIGHTNESS GALAXY VELOCITY FIELDS

    International Nuclear Information System (INIS)

    Kuzio de Naray, Rachel; McGaugh, Stacy S.; Mihos, J. Christopher

    2009-01-01

    We model the Navarro-Frenk-White (NFW) potential to determine if, and under what conditions, the NFW halo appears consistent with the observed velocity fields of low surface brightness (LSB) galaxies. We present mock DensePak Integral Field Unit (IFU) velocity fields and rotation curves of axisymmetric and nonaxisymmetric potentials that are well matched to the spatial resolution and velocity range of our sample galaxies. We find that the DensePak IFU can accurately reconstruct the velocity field produced by an axisymmetric NFW potential and that a tilted-ring fitting program can successfully recover the corresponding NFW rotation curve. We also find that nonaxisymmetric potentials with fixed axis ratios change only the normalization of the mock velocity fields and rotation curves and not their shape. The shape of the modeled NFW rotation curves does not reproduce the data: these potentials are unable to simultaneously bring the mock data at both small and large radii into agreement with observations. Indeed, to match the slow rise of LSB galaxy rotation curves, a specific viewing angle of the nonaxisymmetric potential is required. For each of the simulated LSB galaxies, the observer's line of sight must be along the minor axis of the potential, an arrangement that is inconsistent with a random distribution of halo orientations on the sky.

  16. Potential of hyperspectral imaging to assess the stability of mudflat surfaces by mapping sediment characteristics

    Science.gov (United States)

    Smith, Geoff; Thomson, Andrew; Moller, Iris; Kromkamp, Jacco

    2003-03-01

    This work assessed the suitability of hyperspectral data for estimating mudflat surface characteristics related to stability. Due to the inaccessibility of intertidal areas, precise ground-based measurements of mudflat stability are difficult to conduct. Remote sensing can provide full spatial coverage and non-intrusive measurement. As stability changes on mudflats are linked to subtle differences in mudflat surface characteristics, they can potentially be mapped by hyperspectral data. Hyperspectral images were collected along with near contemporary ground measurements. An unsupervised classification gave a map which confirmed that a channel bar was mainly sand whereas soft mud dominated an adjacent embayment. Multiple regression analysis was used to relate surface characteristics to hyperspectral data to construct regression equations. Erosion shear stress was estimated directly from the hyperspectral data and also by a relationship with the surface characteristics. The results of the thematic class map matched well with the known situation at the site during image acquisition. The maps of surface characteristics highlighted the additional information that can be extracted from hyperspectral data. Stability maps, based on the erosion shear stress, can be used as a basis for predicting the likely future behaviour in this dynamic environment and will be of use for coastal zone management.

  17. Review: the potential impact of surface crystalline states of titanium for biomedical applications.

    Science.gov (United States)

    Barthes, Julien; Ciftci, Sait; Ponzio, Florian; Knopf-Marques, Helena; Pelyhe, Liza; Gudima, Alexandru; Kientzl, Imre; Bognár, Eszter; Weszl, Miklós; Kzhyshkowska, Julia; Vrana, Nihal Engin

    2018-05-01

    In many biomedical applications, titanium forms an interface with tissues, which is crucial to ensure its long-term stability and safety. In order to exert control over this process, titanium implants have been treated with various methods that induce physicochemical changes at nano and microscales. In the past 20 years, most of the studies have been conducted to see the effect of topographical and physicochemical changes of titanium surface after surface treatments on cells behavior and bacteria adhesion. In this review, we will first briefly present some of these surface treatments either chemical or physical and we explain the biological responses to titanium with a specific focus on adverse immune reactions. More recently, a new trend has emerged in titanium surface science with a focus on the crystalline phase of titanium dioxide and the associated biological responses. In these recent studies, rutile and anatase are the major two polymorphs used for biomedical applications. In the second part of this review, we consider this emerging topic of the control of the crystalline phase of titanium and discuss its potential biological impacts. More in-depth analysis of treatment-related surface crystalline changes can significantly improve the control over titanium/host tissue interface and can result in considerable decreases in implant-related complications, which is currently a big burden on the healthcare system.

  18. Perchlorate formation on Mars through surface radiolysis-initiated atmospheric chemistry: A potential mechanism

    Science.gov (United States)

    Wilson, Eric H.; Atreya, Sushil K.; Kaiser, Ralf I.; Mahaffy, Paul R.

    2016-08-01

    Recent observations of the Martian surface by the Phoenix lander and the Sample Analysis at Mars indicate the presence of perchlorate (ClO4-). The abundance and isotopic composition of these perchlorates suggest that the mechanisms responsible for their formation in the Martian environment may be unique in our solar system. With this in mind, we propose a potential mechanism for the production of Martian perchlorate: the radiolysis of the Martian surface by galactic cosmic rays, followed by the sublimation of chlorine oxides into the atmosphere and their subsequent synthesis to form perchloric acid (HClO4) in the atmosphere, and the surface deposition and subsequent mineralization of HClO4 in the regolith to form surface perchlorates. To evaluate the viability of this mechanism, we employ a one-dimensional chemical model, examining chlorine chemistry in the context of Martian atmospheric chemistry. Considering the chlorine oxide, OClO, we find that an OClO flux as low as 3.2 × 107 molecules cm-2 s-1 sublimated into the atmosphere from the surface could produce sufficient HClO4 to explain the perchlorate concentration on Mars, assuming an accumulation depth of 30 cm and integrated over the Amazonian period. Radiolysis provides an efficient pathway for the oxidation of chlorine, bypassing the efficient Cl/HCl recycling mechanism that characterizes HClO4 formation mechanisms proposed for the Earth but not Mars.

  19. Potential of water surface-floating microalgae for biodiesel production: Floating-biomass and lipid productivities.

    Science.gov (United States)

    Muto, Masaki; Nojima, Daisuke; Yue, Liang; Kanehara, Hideyuki; Naruse, Hideaki; Ujiro, Asuka; Yoshino, Tomoko; Matsunaga, Tadashi; Tanaka, Tsuyoshi

    2017-03-01

    Microalgae have been accepted as a promising feedstock for biodiesel production owing to their capability of converting solar energy into lipids through photosynthesis. However, the high capital and operating costs, and high energy consumption, are hampering commercialization of microalgal biodiesel. In this study, the surface-floating microalga, strain AVFF007 (tentatively identified as Botryosphaerella sudetica), which naturally forms a biofilm on surfaces, was characterized for use in biodiesel production. The biofilm could be conveniently harvested from the surface of the water by adsorbing onto a polyethylene film. The lipid productivity of strain AVFF007 was 46.3 mg/L/day, allowing direct comparison to lipid productivities of other microalgal species. The moisture content of the surface-floating biomass was 86.0 ± 1.2%, which was much lower than that of the biomass harvested using centrifugation. These results reveal the potential of this surface-floating microalgal species as a biodiesel producer, employing a novel biomass harvesting and dewatering strategy. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  20. Potential energy surface and rovibrational energy levels of the H2-CS van der Waals complex.

    Science.gov (United States)

    Denis-Alpizar, Otoniel; Stoecklin, Thierry; Halvick, Philippe; Dubernet, Marie-Lise; Marinakis, Sarantos

    2012-12-21

    Owing to its large dipole, astrophysicists use carbon monosulfide (CS) as a tracer of molecular gas in the interstellar medium, often in regions where H(2) is the most abundant collider. Predictions of the rovibrational energy levels of the weakly bound complex CS-H(2) (not yet observed) and also of rate coefficients for rotational transitions of CS in collision with H(2) should help to interpret the observed spectra. This paper deals with the first goal, i.e., the calculation of the rovibrational energy levels. A new four-dimensional intermolecular potential energy surface for the H(2)-CS complex is presented. Ab initio potential energy calculations were carried out at the coupled-cluster level with single and double excitations and a perturbative treatment of triple excitations, using a quadruple-zeta basis set and midbond functions. The potential energy surface was obtained by an analytic fit of the ab initio data. The equilibrium structure of the H(2)-CS complex is found to be linear with the carbon pointing toward H(2) at the intermolecular separation of 8.6 a(o). The corresponding well depth is -173 cm(-1). The potential was used to calculate the rovibrational energy levels of the para-H(2)-CS and ortho-H(2)-CS complexes. The present work provides the first theoretical predictions of these levels. The calculated dissociation energies are found to be 35.9 cm(-1) and 49.9 cm(-1), respectively, for the para and ortho complexes. The second virial coefficient for the H(2)-CS pair has also been calculated for a large range of temperature. These results could be used to assign future experimental spectra and to check the accuracy of the potential energy surface.

  1. Van der Waals enhancement of optical atom potentials via resonant coupling to surface polaritons.

    Science.gov (United States)

    Kerckhoff, Joseph; Mabuchi, Hideo

    2009-08-17

    Contemporary experiments in cavity quantum electrodynamics (cavity QED) with gas-phase neutral atoms rely increasingly on laser cooling and optical, magneto-optical or magnetostatic trapping methods to provide atomic localization with sub-micron uncertainty. Difficult to achieve in free space, this goal is further frustrated by atom-surface interactions if the desired atomic placement approaches within several hundred nanometers of a solid surface, as can be the case in setups incorporating monolithic dielectric optical resonators such as microspheres, microtoroids, microdisks or photonic crystal defect cavities. Typically in such scenarios, the smallest atom-surface separation at which the van der Waals interaction can be neglected is taken to be the optimal localization point for associated trapping schemes, but this sort of conservative strategy generally compromises the achievable cavity QED coupling strength. Here we suggest a new approach to the design of optical dipole traps for atom confinement near surfaces that exploits strong surface interactions, rather than avoiding them, and present the results of a numerical study based on (39)K atoms and indium tin oxide (ITO). Our theoretical framework points to the possibility of utilizing nanopatterning methods to engineer novel modifications of atom-surface interactions. (c) 2009 Optical Society of America

  2. Early interactions between leukocytes and three different potentially bioactive titanium surface modifications.

    Science.gov (United States)

    Arvidsson, Anna; Malmberg, Per; Kjellin, Per; Currie, Fredrik; Arvidsson, Martin; Franke Stenport, Victoria

    2011-05-01

    The aim of the present study was to compare the early interactions between leukocytes and three different surface modifications, suggested as bioactive. Blasted titanium discs were modified by alkali and heat treatment, sodium fluoride treatment, or hydroxyapatite coating. A number of these discs were also immersed in simulated body fluid (SBF) for a week, a treatment which yielded high levels of calcium and phosphate on each surface type. The specimens were exposed for human venous blood for 32 minutes and the respiratory burst response was measured in terms of reactive oxygen species with a luminometer, and coverage of viable cells with a fluorescence microscope after staining steps. The topography, morphology, and chemistry of the surfaces were evaluated with optical interferometry and scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). A high respiratory burst response was found for HA coated titanium in comparison with the other surface groups (p burst response (p < 0.0005) and removed statistically significant differences between the surface groups. Thus, the results in the present study indicate that different titanium surface modifications influence the early inflammatory response differently, and that calcium phosphate compounds increase the inflammatory response. Copyright © 2011 Wiley Periodicals, Inc.

  3. Beyond Massive MIMO: The Potential of Data Transmission With Large Intelligent Surfaces

    Science.gov (United States)

    Hu, Sha; Rusek, Fredrik; Edfors, Ove

    2018-05-01

    In this paper, we consider the potential of data-transmission in a system with a massive number of radiating and sensing elements, thought of as a contiguous surface of electromagnetically active material. We refer to this as a large intelligent surface (LIS). The "LIS" is a newly proposed concept, which conceptually goes beyond contemporary massive MIMO technology, that arises from our vision of a future where man-made structures are electronically active with integrated electronics and wireless communication making the entire environment "intelligent". We consider capacities of single-antenna autonomous terminals communicating to the LIS where the entire surface is used as a receiving antenna array. Under the condition that the surface-area is sufficiently large, the received signal after a matched-filtering (MF) operation can be closely approximated by a sinc-function-like intersymbol interference (ISI) channel. We analyze the capacity per square meter (m^2) deployed surface, \\hat{C}, that is achievable for a fixed transmit power per volume-unit, \\hat{P}. Moreover, we also show that the number of independent signal dimensions per m deployed surface is 2/\\lambda for one-dimensional terminal-deployment, and \\pi/\\lambda^2 per m^2 for two and three dimensional terminal-deployments. Lastly, we consider implementations of the LIS in the form of a grid of conventional antenna elements and show that, the sampling lattice that minimizes the surface-area of the LIS and simultaneously obtains one signal space dimension for every spent antenna is the hexagonal lattice. We extensively discuss the design of the state-of-the-art low-complexity channel shortening (CS) demodulator for data-transmission with the LIS.

  4. The remineralization potential of cocoa (Theobroma cacao bean extract to increase the enamel micro hardness

    Directory of Open Access Journals (Sweden)

    Sulistianingsih Sulistianingsih

    2017-08-01

    Full Text Available Introduction: Remineralization is the process of returning mineral ions into a hydroxyapatite structure characterized by mineral deposition on the enamel surface. The presence of mineral deposition would affect the micro hardness of tooth enamel. The use of fluorine as remineralization agent with side effects such as fluorosis. Cocoa bean extract contains theobromin that can be used as an alternative remineralization ingredients. The objectives was to determine micro hardness email after remineralization using cocoa bean extract as natural material and to compare with fluorine use as synthetic material. Methods: Thirty-six maxillary first premolar tooth crown was cut and planted in the epoxy resin. Teeth were then immersed in demineralization solution at pH 4 for 6 hours. The sample were divided into 2 groups, 18 for the fluorine group and the remaining group of cocoa extract. Vickers microhardness test was used before treatment, after demineralized and after remineralization. Results: Enamel microhardness value before treatment in the fluorine group average value was 376.17 VHN and the cocoa extract group was 357.33 VHN. After demineralization in fluorine group was 268,13 VHN and cocoa extract group was 235,93 VHN. After remineralization in fluorine group was 321,08 VHN and cocoa extract group was 293,86 VHN. The results of the analysis showed that the level of micro hardness email after remineralization was not significantly different in two groups (p > 0.05. Conclusions: Cocoa extract is able to increase the microhardness of enamel so it can act as a substitution for fluorine remineralization.

  5. Proper construction of ab initio global potential surfaces with accurate long-range interactions

    International Nuclear Information System (INIS)

    Ho, Tak-San; Rabitz, Herschel

    2000-01-01

    An efficient procedure based on the reproducing kernel Hilbert space interpolation method is presented for constructing intermolecular potential energy surfaces (PES) using not only calculated ab initio data but also a priori information on long-range interactions. Explicitly, use of the reciprocal power reproducing kernel on the semiinfinite interval [0,∞) yields a set of exact linear relations between dispersion (multipolar) coefficients and PES data points at finite internuclear separations. Consequently, given a combined set of ab initio data and the values of dispersion (multipolar) coefficients, the potential interpolation problem subject to long-range interaction constraints can be solved to render globally smooth, asymptotically accurate ab initio potential energy surfaces. Very good results have been obtained for the one-dimensional He-He potential curve and the two-dimensional Ne-CO PES. The construction of the Ne-CO PES was facilitated by invoking a new reproducing kernel for the angular coordinate based on the optimally stable and shape-preserving Bernstein basis functions. (c) 2000 American Institute of Physics

  6. Effects of PV Module Soiling on Glass Surface Resistance and Potential-Induced Degradation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Hacke, Peter; Burton, Patrick; Hendrickson, Alex; Spartaru, Sergiu; Glick, Stephen; Terwilliger, Kent

    2015-12-03

    The sheet resistance of three soil types (Arizona road dust, soot, and sea salt) on glass were measured by the transmission line method as a function of relative humidity (RH) between 39% and 95% at 60 degrees C. Sea salt yielded a 3.5 order of magnitude decrease in resistance on the glass surface when the RH was increased over this RH range. Arizona road dust showed reduced sheet resistance at lower RH, but with less humidity sensitivity over the range tested. The soot sample did not show significant resistivity change compared to the unsoiled control. Photovoltaic modules with sea salt on their faces were step-stressed between 25% and 95% RH at 60 degrees C applying -1000 V bias to the active cell circuit. Leakage current from the cell circuit to ground ranged between two and ten times higher than that of the unsoiled controls. Degradation rate of modules with salt on the surface increased with increasing RH and time.

  7. Increase of Exports as a Potential Factor for Sustainable Economic Development of Kosovo

    Directory of Open Access Journals (Sweden)

    Dr.Sc. Myrvete Badivuku - Pantina

    2013-12-01

    Full Text Available Kosovo as the newest state in the region, in the economic aspect represents an economic complex with considerable potential of human, economic and demographic resources, having an open economy and entirely Euro integrated, with the central position in Balkan Peninsula. As a new state Kosovo is going through a transition phase and is found in an unsatisfactory position, therefore a serious professional intervention by the competent mechanisms is necessary towards finding an adequate solution which enables a speedier economic, social and cultural development, thus accessing into economic and political integrations in the region and in Europe. Kosovo economy during 2012 was characterised by a positive norm of growth. The real norm of economic growth in the country reached the figure of 2.9 per cent. The slowest developments in the regional and European markets during this year appeared as a challenge for the general economic activity in the country. In 2012, a decrease was marked from several important sources of financing in the country, especially the foreign direct investments. A reduction was also characterised in export of goods, but, growth of export of the services neutralised the effect of decrease of goods export. Kosovo suffers from the negative trade balance, implying that Kosovo depends on imports, whereas its opportunities to export local products into foreign market are very low. With intention of improving the competitive position of Kosovar enterprises, and for increasing export into world market, the existing economic policies need to be amended and supplemented and the institutional functioning needs to be improved as well. The aim of this study is to provide a realistic overview of the economic situation of Kosovo through an overall analysis and to also give recommendations with intention of improving the trade balance in favour of increase of Kosovar export in the future.

  8. Nano surface engineering of Mn 2 O 3 for potential light-harvesting application

    KAUST Repository

    Kar, Prasenjit

    2015-01-01

    Manganese oxides are well known applied materials including their use as efficient catalysts for various environmental applications. Multiple oxidation states and their change due to various experimental conditions are concluded to be responsible for their multifaceted functionality. Here we demonstrate that the interaction of a small organic ligand with one of the oxide varieties induces completely new optical properties and functionalities (photocatalysis). We have synthesized Mn2O3 microspheres via a hydrothermal route and characterized them using scanning electron microscopy (SEM), X-ray diffraction (XRD) and elemental mapping (EDAX). When the microspheres are allowed to interact with the biologically important small ligand citrate, nanometer-sized surface functionalized Mn2O3 (NPs) are formed. Raman and Fourier transformed infrared spectroscopy confirm the covalent attachment of the citrate ligand to the dangling bond of Mn at the material surface. While cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) analysis confirm multiple surface charge states after the citrate functionalization of the Mn2O3 NPs, new optical properties of the surface engineered nanomaterials in terms of absorption and emission emerge consequently. The engineered material offers a novel photocatalytic functionality to the model water contaminant methylene blue (MB). The effect of doping other metal ions including Fe3+ and Cu2+ on the optical and catalytic properties is also investigated. In order to prepare a prototype for potential environmental application of water decontamination, we have synthesized and duly functionalized the material on the extended surface of a stainless steel metal mesh (size 2 cm × 1.5 cm, pore size 150 μm × 200 μm). We demonstrate that the functionalized mesh always works as a "physical" filter of suspended particulates. However, it works as a "chemical" filter (photocatalyst) for the potential water soluble contaminant (MB) in the presence

  9. SU-F-T-424: Mitigation of Increased Surface Dose When Treating Through A Carbon Fiber Couch Top

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E; Misgina, F [University of Kentucky, Lexington, KY (United States)

    2016-06-15

    Purpose: To study the effect of the Varian carbon fiber couch top on surface dose for patients being treated using single PA beams in the supine position and to identify simple methods for surface dose reduction. Methods: Measurements of surface dose were obtained in Solid Water phantoms using both a parallel plate ionization chamber (PTW Advanced Markus) and EBT2 Radiochromic films for both 6 and 10MV photons. All measurements were referenced to a depth considered a typical for PA Spine fields. Techniques used to reduce the surface dose included introducing an air standoff using Styrofoam sheets to suspend the phantom surface above the couch top and by adding a thin high Z scattering foil on the table surface. Surface doses were evaluated for typical field sizes, standoff heights, and various scattering materials. Comparisons were made to the surface dose obtainable when treating through a Varian Mylar covered tennis racket style couch top. Results: Dependence on typical spine field sizes was relatively minor. Dependence on air gap was much more significant. Surface doses decreased exponentially with increases in air standoff distance. Surface doses were reduced by approximately 50% for an air gap of 10cm and 40% for a 15cm air gap. Surface doses were reduced by an additional 15% by the addition of a 1mm Tin scattering foil. Conclusion: Using simple techniques, it is possible to reduce the surface dose when treating single PA fields through the Varian carbon fiber couch top. Surface doses can be reduced to levels observed when treating though transparent Mylar tops by adding about 15 cm of air gap. Further reductions are possible by adding thin scattering foils, such as Tin or Lead, on the couch surface. This is a low cost approach to reduce surface dose when using the Varian carbon fiber couch top.

  10. SU-F-T-424: Mitigation of Increased Surface Dose When Treating Through A Carbon Fiber Couch Top

    International Nuclear Information System (INIS)

    Johnson, E; Misgina, F

    2016-01-01

    Purpose: To study the effect of the Varian carbon fiber couch top on surface dose for patients being treated using single PA beams in the supine position and to identify simple methods for surface dose reduction. Methods: Measurements of surface dose were obtained in Solid Water phantoms using both a parallel plate ionization chamber (PTW Advanced Markus) and EBT2 Radiochromic films for both 6 and 10MV photons. All measurements were referenced to a depth considered a typical for PA Spine fields. Techniques used to reduce the surface dose included introducing an air standoff using Styrofoam sheets to suspend the phantom surface above the couch top and by adding a thin high Z scattering foil on the table surface. Surface doses were evaluated for typical field sizes, standoff heights, and various scattering materials. Comparisons were made to the surface dose obtainable when treating through a Varian Mylar covered tennis racket style couch top. Results: Dependence on typical spine field sizes was relatively minor. Dependence on air gap was much more significant. Surface doses decreased exponentially with increases in air standoff distance. Surface doses were reduced by approximately 50% for an air gap of 10cm and 40% for a 15cm air gap. Surface doses were reduced by an additional 15% by the addition of a 1mm Tin scattering foil. Conclusion: Using simple techniques, it is possible to reduce the surface dose when treating single PA fields through the Varian carbon fiber couch top. Surface doses can be reduced to levels observed when treating though transparent Mylar tops by adding about 15 cm of air gap. Further reductions are possible by adding thin scattering foils, such as Tin or Lead, on the couch surface. This is a low cost approach to reduce surface dose when using the Varian carbon fiber couch top.

  11. Hydrodynamic analysis of potential groundwater extraction capacity increase: case study of 'Nelt' groundwater source at Dobanovci

    Directory of Open Access Journals (Sweden)

    Bajić Dragoljub I.

    2017-01-01

    Full Text Available A comprehensive hydrodynamic analysis of the groundwater regime undertaken to assess the potential for expanding the 'Nelt' groundwater source at Dobanovci, or developing a new groundwater source for a future baby food factory, including the quantification of the impact on the production wells of the nearby 'Pepsi' groundwater source, is presented in the paper. The existing Nelt source is comprised of three active production wells that tap a subartesian aquifer formed in sands and gravelly sands; however, the analysis considers only the two nearest wells. A long-term group pumping test was con-ducted of production wells N-1 and N2 (Nelt source and production wells B-1 and B-2 (Pepsi source, while the piezometric head in the vicinity of these wells was monitored at observation well P-1, which is located in the area considered for Nelt source expansion. Data were collected at maximum pumping capacity of all the production wells. A hydrodynamic model of groundwater flow in the extended area of the Nelt source was generated for the purposes of the comprehensive hydrodynamic analysis. Hydrodynamic prognostic calculations addressed two solution alternatives for the capacity increase over a period of ten years. Licensed Visual MODFLOW Pro software, deemed to be at the very top in this field, was used for the calculations.

  12. Preservation of motor maps with increased motor evoked potential amplitude threshold in RMT determination.

    Science.gov (United States)

    Lucente, Giuseppe; Lam, Steven; Schneider, Heike; Picht, Thomas

    2018-02-01

    Non-invasive pre-surgical mapping of eloquent brain areas with navigated transcranial magnetic stimulation (nTMS) is a useful technique linked to the improvement of surgical planning and patient outcomes. The stimulator output intensity and subsequent resting motor threshold determination (rMT) are based on the motor-evoked potential (MEP) elicited in the target muscle with an amplitude above a predetermined threshold of 50 μV. However, a subset of patients is unable to achieve complete relaxation in the target muscles, resulting in false positives that jeopardize mapping validity with conventional MEP determination protocols. Our aim is to explore the feasibility and reproducibility of a novel mapping approach that investigates how an increase of the MEP amplitude threshold to 300 and 500 μV affects subsequent motor maps. Seven healthy subjects underwent motor mapping with nTMS. RMT was calculated with the conventional methodology in conjunction with experimental 300- and 500-μV MEP amplitude thresholds. Motor mapping was performed with 105% of rMT stimulator intensity using the FDI as the target muscle. Motor mapping was possible in all patients with both the conventional and experimental setups. Motor area maps with a conventional 50-μV threshold showed poor correlation with 300-μV (α = 0.446, p motor area maps (α = 0.974, p motor area mapping with nTMS without losing precision.

  13. Increased nuclear ?-catenin expression in oral potentially malignant lesions: A marker of epithelial dysplasia

    Science.gov (United States)

    Rojas-Alcayaga, Gonzalo; Maturana, Andrea; Aitken, Juan-Pablo; Rojas, Carolina; Ortega, Ana-Verónica

    2015-01-01

    Background Deregulation of ?-catenin is associated with malignant transformation; however, its relationship with potentially malignant and malignant oral processes is not fully understood. The aim of this study was to determine and compare the nuclear ?-catenin expression in oral dysplasia and oral squamous cell carcinoma (OSCC). Material and Methods Cross sectional study. Immunodetection of ?-catenin was performed on 72 samples, with the following distribution: 21 mild dysplasia, 12 moderate dysplasia, severe dysplasia 3, 36 OSCC including 19 well differentiated, 15 moderately differentiated and 2 poorly differentiated. Through microscopic observation the number of positive cells per 1000 epithelial cells was counted. For the statistical analysis, the Kruskal Wallis test was used. Results Nuclear expression of ?-catenin was observed in all samples with severe and moderate dysplasia, with a median of 267.5, in comparison to mild dysplasia whose median was 103.75. Only 10 samples (27.7%) with OSCC showed nuclear expression, with statistically significant differences between groups (p < 0.05). Conclusions Our results are consistent with most of the reports which show increased presence of ?-catenin in severe and moderate dysplasia compared to mild dysplasia; however the expression of nuclear ?-catenin decreased after starting the invasive neoplastic process. This suggests a role for this protein in the progression of dysplasia and early malignant transformation to OSCC. Immunodetection of ?-catenin could be a possible immune marker in the detection of oral dysplasia. Key words:Oral squamous cell carcinoma (OSCC), ?-catenin, oral dysplasia. PMID:26241451

  14. Increased nuclear β-catenin expression in oral potentially malignant lesions: A marker of epithelial dysplasia.

    Science.gov (United States)

    Reyes, Montserrat; Rojas-Alcayaga, Gonzalo; Maturana, Andrea; Aitken, Juan-Pablo; Rojas, Carolina; Ortega, Ana-Verónica

    2015-09-01

    Deregulation of β-catenin is associated with malignant transformation; however, its relationship with potentially malignant and malignant oral processes is not fully understood. The aim of this study was to determine and compare the nuclear β-catenin expression in oral dysplasia and oral squamous cell carcinoma (OSCC). Cross sectional study. Immunodetection of β-catenin was performed on 72 samples, with the following distribution: 21 mild dysplasia, 12 moderate dysplasia, severe dysplasia 3, 36 OSCC including 19 well differentiated, 15 moderately differentiated and 2 poorly differentiated. Through microscopic observation the number of positive cells per 1000 epithelial cells was counted. For the statistical analysis, the Kruskal Wallis test was used. Nuclear expression of β-catenin was observed in all samples with severe and moderate dysplasia, with a median of 267.5, in comparison to mild dysplasia whose median was 103.75. Only 10 samples (27.7%) with OSCC showed nuclear expression, with statistically significant differences between groups (p < 0.05). Our results are consistent with most of the reports which show increased presence of β-catenin in severe and moderate dysplasia compared to mild dysplasia; however the expression of nuclear β-catenin decreased after starting the invasive neoplastic process. This suggests a role for this protein in the progression of dysplasia and early malignant transformation to OSCC. Immunodetection of β-catenin could be a possible immune marker in the detection of oral dysplasia.

  15. The effect of increased intracranial pressure on vestibular evoked myogenic potentials in superior canal dehiscence syndrome.

    Science.gov (United States)

    Janky, Kristen L; Zuniga, M Geraldine; Schubert, Michael C; Carey, John P

    2015-04-01

    To determine if vestibular evoked myogenic potential (VEMP) responses change during inversion in patients with superior canal dehiscence syndrome (SCDS) compared to controls. Sixteen subjects with SCDS (mean: 43, range 30-57 years) and 15 age-matched, healthy subjects (mean: 41, range 22-57 years) completed cervical VEMP (cVEMP) in response to air conduction click stimuli and ocular VEMP (oVEMP) in response to air conduction 500 Hz tone burst stimuli and midline tap stimulation. All VEMP testing was completed in semi-recumbent and inverted conditions. SCDS ears demonstrated significantly larger oVEMP peak-to-peak amplitudes in comparison to normal ears in semi-recumbency. While corrected cVEMP peak-to-peak amplitudes were larger in SCDS ears; this did not reach significance in our sample. Overall, there was not a differential change in o- or cVEMP amplitude with inversion between SCDS and normal subjects. Postural-induced changes in o- and cVEMP responses were measured in the steady state regardless of whether the labyrinth was intact or dehiscent. VEMP responses are blunted during inversion. Although steady-state measurements of VEMPs during inversion do not increase diagnostic accuracy for SCDS, the findings suggest that inversion may provide more general insights into the equilibration of pressures between intracranial and intralabyrinthine fluids. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  16. Antiherding in Financial Decision Increases Valuation of Return on Investment: An Event-Related Potential Study

    Directory of Open Access Journals (Sweden)

    Cuicui Wang

    2017-01-01

    Full Text Available Using event-related potentials, this study investigated how financial herding or antiherding affected the valuation of subsequent outcomes. For each trial, subjects decided whether to buy the stock according to its net money flow information which could be used to reflect the strength of buying power or selling power of the stock. The return on investment (ROI as feedback included the increase or decrease percentage after subjects’ responses. Results showed that, compared with herding, antiherding induced larger discrepancies of FRN and P300 amplitude between positive ROI and negative ROI, indicating that individuals under antiherding condition had stronger motivation and paid more attention in the evaluation process of ROI. Moreover, only for positive ROI, the amplitudes of FRN and P300 were modulated by two kinds of behaviors. We suggested that individuals making antiherd decisions were more confident with their own ability and choices, which reduced the positive outcome prediction error and gave more mental resources to evaluate positive outcome. However, negative outcomes evoked no different motivational meaning and negative emotion for individuals between herding and antiherding. The study may provide new insights into neurocognitive processes of herding and antiherding in financial market.

  17. Antiherding in Financial Decision Increases Valuation of Return on Investment: An Event-Related Potential Study.

    Science.gov (United States)

    Wang, Cuicui; Jin, Jia; Vieito, João Paulo; Ma, Qingguo

    2017-01-01

    Using event-related potentials, this study investigated how financial herding or antiherding affected the valuation of subsequent outcomes. For each trial, subjects decided whether to buy the stock according to its net money flow information which could be used to reflect the strength of buying power or selling power of the stock. The return on investment (ROI) as feedback included the increase or decrease percentage after subjects' responses. Results showed that, compared with herding, antiherding induced larger discrepancies of FRN and P300 amplitude between positive ROI and negative ROI, indicating that individuals under antiherding condition had stronger motivation and paid more attention in the evaluation process of ROI. Moreover, only for positive ROI, the amplitudes of FRN and P300 were modulated by two kinds of behaviors. We suggested that individuals making antiherd decisions were more confident with their own ability and choices, which reduced the positive outcome prediction error and gave more mental resources to evaluate positive outcome. However, negative outcomes evoked no different motivational meaning and negative emotion for individuals between herding and antiherding. The study may provide new insights into neurocognitive processes of herding and antiherding in financial market.

  18. Determination of electrostatic potential distribution by atomic force microscopy (AFM) on model silica and alumina surfaces in aqueous electrolyte solutions

    International Nuclear Information System (INIS)

    Yelken, Gulnihal Ozek; Polat, Mehmet

    2014-01-01

    Graphical abstract: - Highlights: • Atomic force microscopy was employed to quantitatively determine the surface potential on silica and alumina surfaces immersed in aqueous electrolyte solutions at various pH values using the DLVO theory. • Potential distributions could be presented in the form of a potential map by repeating the procedure on multiple locations on these surfaces. • The average potential of the distributions agreed very well with the surface potentials measured by electrophoretic techniques. • Several experimental procedures required to achieve the very sensitive force measurements were outlined and demonstrated. - Abstract: AFM was employed as a physicochemical probe to determine the electrostatic potential distribution quantitatively on selected ideal oxide surfaces (quartz 0 0 0 1 and sapphire 0 0 0 1) in aqueous media. The force of interaction between a silicon nitride tip and the oxide surface was measured at a given point under well-defined solution conditions. Relevant theories were used to isolate the electrostatic component from the total force of interaction which was then employed to estimate the surface potential at that point. Repeating the procedure on selected locations generated a potential map of the surface. Comparison of these potentials with those obtained from independent electrokinetic measurements confirmed the validity of the approach

  19. Increased cell surface metallopeptidase activity in cells undergoing UV-induced apoptosis

    International Nuclear Information System (INIS)

    Piva, T.J.; Davern, C.M.; Ellem, K.A.O.

    1999-01-01

    Full text: We have previously shown that UVC irradiation activated a range of cell surface peptidases (CSP) in HeLa cell monolayer cultures 20 h post-irradiation (1). In cells undergoing apoptosis there is an increase in CSP activity compared to control viable cells in cultures which have been treated by a wide range of agents including UV-irradiation (2). In order to further understand the mechanism involved in this process, we induced apoptosis in HeLa cells using 500 Jm -2 UVB. The separation of viable, apoptotic and necrotic cells of irradiated HeLa cell cultures was made by FACS analysis and sorting. The three populations were distinguished by their staining with PI and Hoechst 33342 dyes. CSP activity was measured using the P9 assay developed in this laboratory (1-3). The viable fraction of the irradiated cells had a higher level of CSP activity compared to unirradiated controls. The level of CSP activity in the apoptotic fraction was higher than that of the viable fraction, however that of the necrotic fraction was significantly lower. This finding agreed with that seen in UVC-irradiated (50 Jm -2 ) cultures (2). In order to elucidate the mechanism by which CSP activity was increased in UVB-irradiated cells undergoing apoptosis, the cultures were treated with the following agents: bestatin, aminopeptidase inhibitor, DEVD, caspase 3 inhibitor, and 3-aminobenzamide (3AB), PARP activation inhibitor. Bestatin and DEVD did not affect the level of CSP activity in the different cell subpopulations following UVB-irradiation. Treatment with 3AB abolished the increased CSP activity seen in the viable and apoptotic fraction following UVB-irradiation. All treated cells had the same morphology as observed under EM. The degree of phosphatidylserine eversion on the cell membrane was similar as were the cleavage profiles of PARP and actin. Only DEVD-treated cells had reduced caspase 3 activity which confirmed that the activation of CSP activity in apoptotic cells is

  20. Reduced bacterial growth and increased osteoblast proliferation on titanium with a nanophase TiO2surface treatment.

    Science.gov (United States)

    Bhardwaj, Garima; Webster, Thomas J

    2017-01-01

    The attachment and initial growth of bacteria on an implant surface dictates the progression of infection. Treatment often requires aggressive antibiotic use, which does not always work. To overcome the difficulties faced in systemic and local antibiotic delivery, scientists have forayed into using alternative techniques, which includes implant surface modifications that prevent initial bacterial adhesion, foreign body formation, and may offer a controlled inflammatory response. The current study focused on using electrophoretic deposition to treat titanium with a nanophase titanium dioxide surface texture to reduce bacterial adhesion and growth. Two distinct nanotopographies were analyzed, Ti-160, an antimicrobial surface designed to greatly reduce bacterial colonization, and Ti-120, an antimicrobial surface with a topography that upregulates osteoblast activity while reducing bacterial colonization; the number following Ti in the nomenclature represents the atomic force microscopy root-mean-square roughness value in nanometers. There was a 95.6% reduction in Staphylococcus aureus (gram-positive bacteria) for the Ti-160-treated surfaces compared to the untreated titanium alloy controls. There was a 90.2% reduction in Pseudomonas aeruginosa (gram-negative bacteria) on Ti-160-treated surfaces compared to controls. For ampicillin-resistant Escherichia coli , there was an 81.1% reduction on the Ti-160-treated surfaces compared to controls. Similarly for surfaces treated with Ti-120, there was an 86.8% reduction in S. aureus , an 82.1% reduction in P. aeruginosa , and a 48.6% reduction in ampicillin-resistant E. coli . The Ti-120 also displayed a 120.7% increase at day 3 and a 168.7% increase at day 5 of osteoblast proliferation over standard titanium alloy control surfaces. Compared to untreated surfaces, Ti-160-treated titanium surfaces demonstrated a statistically significant 1 log reduction in S. aureus and P. aeruginosa , whereas Ti-120 provided an additional

  1. The Leidenfrost temperature increase for impacting droplets on carbon-nanofiber surfaces.

    Science.gov (United States)

    Nair, Hrudya; Staat, Hendrik J J; Tran, Tuan; van Houselt, Arie; Prosperetti, Andrea; Lohse, Detlef; Sun, Chao

    2014-04-07

    Droplets impacting on a superheated surface can either exhibit a contact boiling regime, in which they make direct contact with the surface and boil violently, or a film boiling regime, in which they remain separated from the surface by their own vapor. The transition from the contact to the film boiling regime depends not only on the temperature of the surface and the kinetic energy of the droplet, but also on the size of the structures fabricated on the surface. Here we experimentally show that surfaces covered with carbon-nanofibers delay the transition to film boiling to much higher temperatures compared to smooth surfaces. We present physical arguments showing that, because of the small scale of the carbon fibers, they are cooled by the vapor flow just before the liquid impact, thus permitting contact boiling up to much higher temperatures than on smooth surfaces. We also show that as long as the impact is in the film boiling regime, the spreading factor of impacting droplets is consistent with the We(3/10) scaling (with We being the Weber number) as predicted for large We by a scaling analysis.

  2. Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt

    Science.gov (United States)

    Abdalla, Fathy; Khalil, Ramadan

    2018-05-01

    The potential effects of anthropogenic activities, in particular, unsafe sewage disposal practices, on shallow groundwater in an unconfined aquifer and on surface water were evaluated within an urban area by the use of hydrogeological, hydrochemical, and bacteriological analyses. Physicochemical and bacteriological data was obtained from forty-five sampling points based on33 groundwater samples from variable depths and 12 surface water samples. The pollution sources are related to raw sewage and wastewater discharges, agricultural runoff, and wastewater from the nearby Paper Factory. Out of the 33 groundwater samples studied, 17 had significant concentrations of NO3-, Cl- and SO42-, and high bacteria counts. Most of the water samples from the wells contained high Fe, Mn, Pb, Zn, Cd, and Cr. The majority of surface water samples presented high NO3- concentrations and high bacteria counts. A scatter plot of HCO3- versus Ca indicates that 58% of the surface water samples fall within the extreme contamination zone, while the others are within the mixing zone; whereas 94% of groundwater samples showed evidence of mixing between groundwater and wastewater. The bacteriological assessment showed that all measured surface and groundwater samples contained Escherichia coli and total coliform bacteria. A risk map delineated four classes of contamination, namely, those sampling points with high (39.3%), moderate (36.3%), low (13.3%), and very low (11.1%) levels of contamination. Most of the highest pollution points were in the middle part of the urban area, which suffers from unmanaged sewage and industrial effluents. Overall, the results demonstrate that surface and groundwater in Qus City are at high risk of contamination by wastewater since the water table is shallow and there is a lack of a formal sanitation network infrastructure. The product risk map is a useful tool for prioritizing zones that require immediate mitigation and monitoring.

  3. Potential energy surface of triplet N{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Varga, Zoltan; Meana-Pañeda, Rubén; Song, Guoliang; Paukku, Yuliya; Truhlar, Donald G., E-mail: truhlar@umn.edu [Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431 (United States)

    2016-01-14

    We present a global ground-state triplet potential energy surface for the N{sub 2}O{sub 2} system that is suitable for treating high-energy vibrational-rotational energy transfer and collision-induced dissociation. The surface is based on multi-state complete-active-space second-order perturbation theory/minimally augmented correlation-consistent polarized valence triple-zeta electronic structure calculations plus dynamically scaled external correlation. In the multireference calculations, the active space has 14 electrons in 12 orbitals. The calculations cover nine arrangements corresponding to dissociative diatom-diatom collisions of N{sub 2}, O{sub 2}, and nitric oxide (NO), the interaction of a triatomic molecule (N{sub 2}O and NO{sub 2}) with the fourth atom, and the interaction of a diatomic molecule with a single atom (i.e., the triatomic subsystems). The global ground-state potential energy surface was obtained by fitting the many-body interaction to 54 889 electronic structure data points with a fitting function that is a permutationally invariant polynomial in terms of bond-order functions of the six interatomic distances.

  4. Substance P Increases Cell-Surface Expression of CD74 (Receptor for Macrophage Migration Inhibitory Factor: In Vivo Biotinylation of Urothelial Cell-Surface Proteins

    Directory of Open Access Journals (Sweden)

    Katherine L. Meyer-Siegler

    2009-01-01

    N-hydroxysulfosuccinimide biotin ester-labeled surface urothelial proteins in rats treated either with saline or substance P (SP, 40 μg/kg. The bladder was examined by histology and confocal microscopy. Biotinylated proteins were purified by avidin agarose, immunoprecipitated with anti-MIF or anti-CD74 antibodies, and detected with strepavidin-HRP. Only superficial urothelial cells were biotinylated. These cells contained a biotinylated MIF/CD74 cell-surface complex that was increased in SP-treated animals. SP treatment increased MIF and CD74 mRNA in urothelial cells. Our data indicate that intraluminal MIF, released from urothelial cells as a consequence of SP treatment, interacts with urothelial cell-surface CD74. These results document that our previously described MIF-CD74 interaction occurs at the urothelial cell surface.

  5. Calcium Increases Xylella fastidiosa Surface Attachment, Biofilm Formation, and Twitching Motility

    Science.gov (United States)

    Cruz, Luisa F.; Cobine, Paul A.

    2012-01-01

    Xylella fastidiosa is a plant-pathogenic bacterium that forms biofilms inside xylem vessels, a process thought to be influenced by the chemical composition of xylem sap. In this work, the effect of calcium on the production of X. fastidiosa biofilm and movement was analyzed under in vitro conditions. After a dose-response study with 96-well plates using eight metals, the strongest increase of biofilm formation was observed when medium was supplemented with at least 1.0 mM CaCl2. The removal of Ca by extracellular (EGTA, 1.5 mM) and intracellular [1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester (BAPTA/AM), 75 μM] chelators reduced biofilm formation without compromising planktonic growth. The concentration of Ca influenced the force of adhesion to the substrate, biofilm thickness, cell-to-cell aggregation, and twitching motility, as shown by assays with microfluidic chambers and other assays. The effect of Ca on attachment was lost when cells were treated with tetracycline, suggesting that Ca has a metabolic or regulatory role in cell adhesion. A double mutant (fimA pilO) lacking type I and type IV pili did not improve biofilm formation or attachment when Ca was added to the medium, while single mutants of type I (fimA) or type IV (pilB) pili formed more biofilm under conditions of higher Ca concentrations. The concentration of Ca in the medium did not significantly influence the levels of exopolysaccharide produced. Our findings indicate that the role of Ca in biofilm formation may be related to the initial surface and cell-to-cell attachment and colonization stages of biofilm establishment, which rely on critical functions by fimbrial structures. PMID:22194297

  6. Effect of surface functionalizations of multi-walled carbon nanotubes on neoplastic transformation potential in primary human lung epithelial cells.

    Science.gov (United States)

    Stueckle, Todd A; Davidson, Donna C; Derk, Ray; Wang, Peng; Friend, Sherri; Schwegler-Berry, Diane; Zheng, Peng; Wu, Nianqiang; Castranova, Vince; Rojanasakul, Yon; Wang, Liying

    2017-06-01

    Functionalized multi-walled carbon nanotube (fMWCNT) development has been intensified to improve their surface activity for numerous applications, and potentially reduce toxic effects. Although MWCNT exposures are associated with lung tumorigenesis in vivo, adverse responses associated with exposure to different fMWCNTs in human lung epithelium are presently unknown. This study hypothesized that different plasma-coating functional groups determine MWCNT neoplastic transformation potential. Using our established model, human primary small airway epithelial cells (pSAECs) were continuously exposed for 8 and 12 weeks at 0.06 μg/cm 2 to three-month aged as-prepared-(pMWCNT), carboxylated-(MW-COOH), and aminated-MWCNTs (MW-NH x ). Ultrafine carbon black (UFCB) and crocidolite asbestos (ASB) served as particle controls. fMWCNTs were characterized during storage, and exposed cells were assessed for several established cancer cell hallmarks. Characterization analyses conducted at 0 and 2 months of aging detected a loss of surface functional groups over time due to atmospheric oxidation, with MW-NH x possessing less oxygen and greater lung surfactant binding affinity. Following 8 weeks of exposure, all fMWCNT-exposed cells exhibited significant increased proliferation compared to controls at 7 d post-treatment, while UFCB- and ASB-exposed cells did not differ significantly from controls. UFCB, pMWCNT, and MW-COOH exposure stimulated significant transient invasion behavior. Conversely, aged MW-NH x -exposed cells displayed moderate increases in soft agar colony formation and morphological transformation potential, while UFCB cells showed a minimal effect compared to all other treatments. In summary, surface properties of aged fMWCNTs can impact cell transformation events in vitro following continuous, occupationally relevant exposures.

  7. Ab initio treatment of the chemical reaction precursor complex Br(2P)-HCN. 1. Adiabatic and diabatic potential surfaces

    NARCIS (Netherlands)

    Fishchuk, A.V.; Merritt, J.M.; Avoird, A. van der

    2007-01-01

    The three adiabatic potential surfaces of the Br(P-2)-HCN complex that correlate to the P-2 ground state of the Br atom were calculated ab initio. With the aid of a geometry-dependent diabatic mixing angle, also calculated ab initio, these adiabatic potential surfaces were transformed into a set of

  8. High Accuracy Potential Energy Surface, Dipole Moment Surface, Rovibrational Energies and Line List Calculations for ^{14}NH_3

    Science.gov (United States)

    Coles, Phillip; Yurchenko, Sergei N.; Polyansky, Oleg; Kyuberis, Aleksandra; Ovsyannikov, Roman I.; Zobov, Nikolay Fedorovich; Tennyson, Jonathan

    2017-06-01

    We present a new spectroscopic potential energy surface (PES) for ^{14}NH_3, produced by refining a high accuracy ab initio PES to experimental energy levels taken predominantly from MARVEL. The PES reproduces 1722 matched J=0-8 experimental energies with a root-mean-square error of 0.035 cm-1 under 6000 cm^{-1} and 0.059 under 7200 cm^{-1}. In conjunction with a new DMS calculated using multi reference configuration interaction (MRCI) and H=aug-cc-pVQZ, N=aug-cc-pWCVQZ basis sets, an infrared (IR) line list has been computed which is suitable for use up to 2000 K. The line list is used to assign experimental lines in the 7500 - 10,500 cm^{-1} region and previously unassigned lines in HITRAN in the 6000-7000 cm^{-1} region. Oleg L. Polyansky, Roman I. Ovsyannikov, Aleksandra A. Kyuberis, Lorenzo Lodi, Jonathan Tennyson, Andrey Yachmenev, Sergei N. Yurchenko, Nikolai F. Zobov, J. Mol. Spec., 327 (2016) 21-30 Afaf R. Al Derzia, Tibor Furtenbacher, Jonathan Tennyson, Sergei N. Yurchenko, Attila G. Császár, J. Quant. Spectrosc. Rad. Trans., 161 (2015) 117-130

  9. The Increased Production Efficiency and Optimization Terms of Stationarity by Flat Grinding with Abrasive Circle Surface

    Directory of Open Access Journals (Sweden)

    Husseinov Hassan Ahmad

    2014-01-01

    Full Text Available This scientific work deals with the production area. The paper investigates the problems related to the uneven abrasive effect on the processed surface by flat grinding with the abrasive circle surface, and the analytical expression of pattern distribution of the working abrasive grain within the limits of various technological primitives and inaccuracy of geometric shape have been determined. The ways of stationary provision of the grinding surface have been suggested. This paper also focuses on the economic efficiency of the production.

  10. Measurement of the electric potential at the surface of nonuniformly charged polypropylene nonwoven media

    Science.gov (United States)

    Fatihou, Ali; Zouzou, Noureddine; Iuga, Gheorghe; Dascalescu, Lucian

    2015-10-01

    The aim of this paper is to establish the conditions in which the vibrating capacitive probe of an electrostatic voltmeter could be employed for mapping the electric potential at the surface of non-uniformly charged insulating bodies. A first set of experiments are performed on polypropylene non-woven media (thickness: 0.4 mm; fiber diameter: 20 μm) in ambient air. In a second set of experiments the non-uniformity of charge is simulated using five copper strips (width: 2 mm or 3 mm; distance between strips: 2 mm). All the strips are connected to a high-voltage supply (Vs = 1000 V). The sample carrier is attached to a computer-controlled positioning system that transfers it under the capacitive probe (TREK, model 3451) of an electrostatic voltmeter (TREK, model 1341B). The measurements are performed at various relative speeds Vb between the sample and the probe, and for various sample rates Fe. A first set of experiments point out that the electric potential displayed by the electrostatic voltmeter depends on the spacing h between the sample and the probe. The diameter D of the spot “seen” by the probe is approximately D ≈ 8h/3. From the second set of experiments performed with the test plate, it can be concluded that the surface potential can be measured with the media in motion, but the accuracy is limited by the spatial resolution defined by k = Vb/Fe.

  11. Multiparametric Kelvin Probe Force Microscopy for the Simultaneous Mapping of Surface Potential and Nanomechanical Properties.

    Science.gov (United States)

    Xie, Hui; Zhang, Hao; Hussain, Danish; Meng, Xianghe; Song, Jianmin; Sun, Lining

    2017-03-21

    We report high-resolution multiparametric kelvin probe force microscopy (MP-KPFM) measurements for the simultaneous quantitative mapping of the contact potential difference (CPD) and nanomechanical properties of the sample in single-pass mode. This method combines functionalities of the force-distance-based atomic force microscopy and amplitude-modulation (AM) KPFM to perform measurements in single-pass mode. During the tip-sample approach-and-retract cycle, nanomechanical measurements are performed for the retract part of nanoindentation, and the CPD is measured by the lifted probe with a constant tip-sample distance. We compare the performance of the proposed method with the conventional KPFMs by mapping the CPD of multilayer graphene deposited on n-doped silicon, and the results demonstrate that MP-KPFM has comparable performance to AM-KPFM. In addition, the experimental results of a custom-fabricated polymer grating with heterogeneous surfaces validate the multiparametric imaging capability of the MP-KPFM. This method can have potential applications in finding the inherent link between nanomechanical properties and the surface potential of the materials, such as the quantification of the electromechanical response of the deformed piezoelectric materials.

  12. Modeling Images of Natural 3D Surfaces: Overview and Potential Applications

    Science.gov (United States)

    Jalobeanu, Andre; Kuehnel, Frank; Stutz, John

    2004-01-01

    Generative models of natural images have long been used in computer vision. However, since they only describe the of 2D scenes, they fail to capture all the properties of the underlying 3D world. Even though such models are sufficient for many vision tasks a 3D scene model is when it comes to inferring a 3D object or its characteristics. In this paper, we present such a generative model, incorporating both a multiscale surface prior model for surface geometry and reflectance, and an image formation process model based on realistic rendering, the computation of the posterior model parameter densities, and on the critical aspects of the rendering. We also how to efficiently invert the model within a Bayesian framework. We present a few potential applications, such as asteroid modeling and Planetary topography recovery, illustrated by promising results on real images.

  13. CASSCF/CI calculations of electronic states and potential energy surfaces of PtH2

    International Nuclear Information System (INIS)

    Balasubramanian, K.

    1987-01-01

    Complete active space MCSCF followed by MRSDCI (multireference singles and doubles configuration interaction) calculations are carried out on the electronic states of PtH 2 . Spin--orbit interaction is introduced using a relativistic configuration interaction scheme on PtH + whose d orbital Mulliken population is close to that of the d population of PtH 2 and thus enables calculation of spin--orbit splittings for the electronic states of PtH 2 . The bending potential energy surfaces of the 1 A 1 and 3 A 1 states are obtained. The 1 A 1 surface has a bent minimum and dissociates almost without a barrier into Pt( 1 S 0 ) and H 2 , while the 3 A 1 state has a large (--55 kcal/mol) barrier to dissociation into Pt( 3 D 3 )+H 2 . The ground state of PtH 2 is a bent 1 A 1 state (θ = 85 0 )

  14. Rotational Energy Transfer of N2 Determined Using a New Ab Initio Potential Energy Surface

    Science.gov (United States)

    Huo, Winifred M.; Stallcop, James R.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    A new N2-N2 rigid-rotor surface has been determined using extensive Ab Initio quantum chemistry calculations together with recent experimental data for the second virial coefficient. Rotational energy transfer is studied using the new potential energy surface (PES) employing the close coupling method below 200 cm(exp -1) and coupled state approximation above that. Comparing with a previous calculation based on the PES of van der Avoird et al.,3 it is found that the new PES generally gives larger cross sections for large (delta)J transitions, but for small (delta)J transitions the cross sections are either comparable or smaller. Correlation between the differences in the cross sections and the two PES will be attempted. The computed cross sections will also be compared with available experimental data.

  15. Investigation of wild species potential to increase genetic diversity useful for apple breeding

    Directory of Open Access Journals (Sweden)

    Dan Catalina

    2015-01-01

    Full Text Available The potential of testing new apple cultivars and the possibility to induce valuable traits is directly dependent on the availability of sufficient genetic diversity, while apple breeding has narrowed the genetic ground of commercial cultivars. Wild species were studied in regard to their influence upon progenies and their capacity to enlarge apple genetic diversity. The interspecific seedlings were framed in five biparental mating (paired crosses, in which Malus species were crossed with different cultivars, obtaining half-sib families. The number of F1 progenies per combination varied from 31 (Cluj 218/2 × M. floribunda up to 142 (Reinette Baumann × M. floribunda, with a total of 1650 hybrids F1. The influences upon vigour and juvenile period and possible correlation among fruit size and taste were analyzed. Juvenile period varied from 6.00 (M. zumi × Jonathan to 9.31 years (Cluj 218/2 × M. floribunda. Data based on correlation coefficient illustrated that the fructification year was not influenced by the vigour of trees. The highest value of correlation for fruit’s size and taste was obtained among M. coronaria hybrids. This result might suggest that once the fruit are larger, there is a high chance the taste is also more appreciative and fruit quality for mouth feels increase. Depending on the parental formula, additive effects may be inferior compared to genetic effects of dominance and epistasis. Although M. zumi and M. floribunda achieved the same genetic gain (0.31, M. zumi had a higher expected selection response for fruit size. The difficulty of obtaining seedlings with tasty and large fruit when wild Malus species are used as genitors is resulting from the values of expected selection response data, but in the same time results confirm that wild Malus species are suitable resources for genetic variability, both for dessert and ornamental apple cultivars.

  16. Theoretical characterization of the potential energy surface for H + O2 yields HO2(asterisk) yields HO + O. II - The potential for H atom exchange in HO2

    Science.gov (United States)

    Walch, Stephen P.; Rohlfing, Celeste Mcmichael

    1989-01-01

    The results of CASSCF multireference contracted CI calculations with large ANO basis sets are presented for the exchange region of the HO2 potential-energy surface. The saddle point for H atom exchange is about 13 kcal/mol below the energy of H + O2; therefore, this region of the surface should be accessible during H + O2 recombination and methathesis reactions.

  17. Surface-active biopolymers from marine bacteria for potential biotechnological applications

    OpenAIRE

    Karina Sałek; Tony Gutierrez

    2016-01-01

    Surface-active agents are amphiphilic chemicals that are used in almost every sector of modern industry, the bulk of which are produced by organo-chemical synthesis. Those produced from biological sources (biosurfactants and bioemulsifiers), however, have gained increasing interest in recent years due to their wide structural and functional diversity, lower toxicities and high biodegradability, compared to their chemically-synthesised counterparts. This review aims to present a general overvi...

  18. Indexing aortic valve area by body surface area increases the prevalence of severe aortic stenosis

    DEFF Research Database (Denmark)

    Jander, Nikolaus; Gohlke-Bärwolf, Christa; Bahlmann, Edda

    2014-01-01

    To account for differences in body size in patients with aortic stenosis, aortic valve area (AVA) is divided by body surface area (BSA) to calculate indexed AVA (AVAindex). Cut-off values for severe stenosis are......To account for differences in body size in patients with aortic stenosis, aortic valve area (AVA) is divided by body surface area (BSA) to calculate indexed AVA (AVAindex). Cut-off values for severe stenosis are...

  19. Health risk implications of potentially toxic metals in street dust and surface soil of Tehran, Iran.

    Science.gov (United States)

    Dehghani, Sharareh; Moore, Farid; Keshavarzi, Behnam; Hale, Beverley A

    2017-02-01

    In this study a total of 30 street dusts and 10 surface soils were collected in the central district of Tehran and analyzed for major potentially toxic metals. Street dust was found to be greatly enriched in Sb, Pb, Cu and Zn and moderately enriched in Cr, Mn, Mo and Ni. Contamination of Cu, Sb, Pb and Zn was clearly related to anthropogenic sources such as brake wear, tire dust, road abrasion and fossil fuel combustion. Spatial distribution of pollution load index in street dust suggested that industries located south-west of the city intensify street dust pollution. Microscopic studies revealed six dominant group of morphological structures in calculation of the exposurethe street dusts and surface soils, with respect to different geogenic and anthropogenic sources. The BCR (the European Community Bureau of Reference) sequential extraction results showed that Sb, Ni, Mo, As and Cr bonded to silicates and sulfide minerals were highly resistant to dissolution. In contrast, Zn, Cd, and Mn were mostly associated with the exchangeable phase and thus would be easily mobilized in the environment. Cu was the most abundant metal in the reducible fraction, indicating its adsorption to iron and manganese oxy-hydroxides. Pb was equally extracted from exchangeable and reducible fractions. Anthropogenic sources related to traffic apparently play a small role in Cr, Ni and Mo contamination and dispersed them as bioavailable forms but with reduced mobility and bioavailablity due to high potential of complexation and adsorption to organic matter and iron and manganese oxy-hydroxides. Calculated Hazard Index (HI) suggests ingestion as the most important pathway for the majority of PTMs in children and dermal contact as the main exposure route for Cr, Cd and Sb for adults. The HIs and fractionation pattern of elements revealed Pb as the sole element that bears potential health risk in street dust and surface soil. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Identifying Key Issues and Potential Solutions for Integrated Arrival, Departure, Surface Operations by Surveying Stakeholder Preferences

    Science.gov (United States)

    Aponso, Bimal; Coppenbarger, Richard A.; Jung, Yoon; Quon, Leighton; Lohr, Gary; O’Connor, Neil; Engelland, Shawn

    2015-01-01

    NASA's Aeronautics Research Mission Directorate (ARMD) collaborates with the FAA and industry to provide concepts and technologies that enhance the transition to the next-generation air-traffic management system (NextGen). To facilitate this collaboration, ARMD has a series of Airspace Technology Demonstration (ATD) sub-projects that develop, demonstrate, and transitions NASA technologies and concepts for implementation in the National Airspace System (NAS). The second of these sub-projects, ATD-2, is focused on the potential benefits to NAS stakeholders of integrated arrival, departure, surface (IADS) operations. To determine the project objectives and assess the benefits of a potential solution, NASA surveyed NAS stakeholders to understand the existing issues in arrival, departure, and surface operations, and the perceived benefits of better integrating these operations. NASA surveyed a broad cross-section of stakeholders representing the airlines, airports, air-navigation service providers, and industry providers of NAS tools. The survey indicated that improving the predictability of flight times (schedules) could improve efficiency in arrival, departure, and surface operations. Stakeholders also mentioned the need for better strategic and tactical information on traffic constraints as well as better information sharing and a coupled collaborative planning process that allows stakeholders to coordinate IADS operations. To assess the impact of a potential solution, NASA sketched an initial departure scheduling concept and assessed its viability by surveying a select group of stakeholders for a second time. The objective of the departure scheduler was to enable flights to move continuously from gate to cruise with minimal interruption in a busy metroplex airspace environment using strategic and tactical scheduling enhanced by collaborative planning between airlines and service providers. The stakeholders agreed that this departure concept could improve schedule

  1. Surface potential variations on a silicon nanowire transistor in biomolecular modification and detection

    International Nuclear Information System (INIS)

    Tsai, Chia-Chang; Chiang, Pei-Ling; Lin, Tsung-Wu; Chen, Yit-Tsong; Sun, Chih-Jung; Tsai, Ming-Hsueh; Chang, Yun-Chorng

    2011-01-01

    Using a silicon nanowire field-effect transistor (SiNW-FET) for biomolecule detections, we selected 3-(mercaptopropyl)trimethoxysilane (MPTMS), N-[6-(biotinamido)hexyl]-3 ' -(2 ' -pyridyldithio) propionamide (biotin-HPDP), and avidin, respectively, as the designated linker, receptor, and target molecules as a study model, where the biotin molecules were modified on the SiNW-FET to act as a receptor for avidin. We applied high-resolution scanning Kelvin probe force microscopy (KPFM) to detect the modified/bound biomolecules by measuring the induced change of the surface potential (ΔΦ s ) on the SiNW-FET under ambient conditions. After biotin-immobilization and avidin-binding, the ΔΦ s on the SiNW-FET characterized by KPFM was demonstrated to correlate to the conductance change inside the SiNW-FET acquired in aqueous solution. The ΔΦ s values on the SiNW-FET caused by the same biotin-immobilization and avidin-binding were also measured from drain current versus gate voltage curves (I d -V g ) in both aqueous condition and dried state. For comparison, we also study the ΔΦ s values on a Si wafer caused by the same biotin-immobilization and avidin-binding through KPFM and ζ potential measurements. This study has demonstrated that the surface potential measurement on a SiNW-FET by KPFM can be applied as a diagnostic tool that complements the electrical detection with a SiNW-FET sensor. Although the KPFM experiments were carried out under ambient conditions, the measured surface properties of a SiNW-FET are qualitatively valid compared with those obtained by other biosensory techniques performed in liquid environment.

  2. Potential and Actual impacts of deforestation and afforestation on land surface temperature

    Science.gov (United States)

    Li, Yan; Zhao, Maosheng; Mildrexler, David J.; Motesharrei, Safa; Mu, Qiaozhen; Kalnay, Eugenia; Zhao, Fang; Li, Shuangcheng; Wang, Kaicun

    2016-12-01

    Forests are undergoing significant changes throughout the globe. These changes can modify water, energy, and carbon balance of the land surface, which can ultimately affect climate. We utilize satellite data to quantify the potential and actual impacts of forest change on land surface temperature (LST) from 2003 to 2013. The potential effect of forest change on temperature is calculated by the LST difference between forest and nearby nonforest land, whereas the actual impact on temperature is quantified by the LST trend difference between deforested (afforested) and nearby unchanged forest (nonforest land) over several years. The good agreement found between potential and actual impacts both at annual and seasonal levels indicates that forest change can have detectable impacts on surface temperature trends. That impact, however, is different for maximum and minimum temperatures. Overall, deforestation caused a significant warming up to 0.28 K/decade on average temperature trends in tropical regions, a cooling up to -0.55 K/decade in boreal regions, a weak impact in the northern temperate regions, and strong warming (up to 0.32 K/decade) in the southern temperate regions. Afforestation induced an opposite impact on temperature trends. The magnitude of the estimated temperature impacts depends on both the threshold and the data set (Moderate Resolution Imaging Spectroradiometer and Landsat) by which forest cover change is defined. Such a latitudinal pattern in temperature impact is mainly caused by the competing effects of albedo and evapotranspiration on temperature. The methodology developed here can be used to evaluate the temperature change induced by forest cover change around the globe.

  3. Modified titanium surface with gelatin nano gold composite increases osteoblast cell biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young-Hee; Bhattarai, Govinda [Department of Oral Biochemistry, School of Dentistry and Institute of Oral Bioscience, BK21 program, Chonbuk National University, Jeonju (Korea, Republic of); Aryal, Santosh [Department of Bionanosystem Engineering, Chonbuk National University, Jeonju (Korea, Republic of); Lee, Nan-Hee [Department of Oral Biochemistry, School of Dentistry and Institute of Oral Bioscience, BK21 program, Chonbuk National University, Jeonju (Korea, Republic of); Lee, Min-Ho [Department of Dental Biomaterials, School of Dentistry and Institute of Oral Bioscience, BK21 program, Chonbuk National University, Jeonju (Korea, Republic of); Kim, Tae-Gun [Department of Conservative Dentistry, School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Jhee, Eun-Chung [Department of Oral Biochemistry, School of Dentistry and Institute of Oral Bioscience, BK21 program, Chonbuk National University, Jeonju (Korea, Republic of); Kim, Hak-Yong [Department of Bionanosystem Engineering, Chonbuk National University, Jeonju (Korea, Republic of); Yi, Ho-Keun, E-mail: yihokn@chonbuk.ac.kr [Department of Oral Biochemistry, School of Dentistry and Institute of Oral Bioscience, BK21 program, Chonbuk National University, Jeonju (Korea, Republic of)

    2010-08-01

    This study examined the gelatin nano gold (GnG) composite for surface modification of titanium in addition to insure biocompatibility on dental implants or biomaterials. The GnG composite was constructed by gelatin and hydrogen tetrachloroaurate in presence of reducing agent, sodium borohydrate (NabH{sub 4}). The GnG composite was confirmed by UV-VIS spectroscopy and transmission electron microscopy (TEM). A dipping method was used to modify the titanium surface by GnG composite. Surface was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The MC-3T3 E1 cell viability was assessed by trypan blue and the expression of proteins to biocompatibility were analyzed by Western blotting. The GnG composite showed well dispersed character, the strong absorption at 530 nm, roughness, regular crystal and clear C, Na, Cl, P, and Au signals onto titanium. Further, this composite allowed MC-3T3 E1 growth and viability compared to gelatin and pure titanium. It induced ERK activation and the expression of cell adherent molecules, FAK and SPARC, and growth factor, VEGF. However, GnG decreased the level of SAPK/JNK. This shows that GnG composite coated titanium surfaces have a good biocompatibility for osteoblast growth and attachment than in intact by simple and versatile dipping method. Furthermore, it offers good communication between cell and implant surfaces by regulating cell signaling and adherent molecules, which are useful to enhance the biocompatibility of titanium surfaces.

  4. Modified titanium surface with gelatin nano gold composite increases osteoblast cell biocompatibility

    Science.gov (United States)

    Lee, Young-Hee; Bhattarai, Govinda; Aryal, Santosh; Lee, Nan-Hee; Lee, Min-Ho; Kim, Tae-Gun; Jhee, Eun-Chung; Kim, Hak-Yong; Yi, Ho-Keun

    2010-08-01

    This study examined the gelatin nano gold (GnG) composite for surface modification of titanium in addition to insure biocompatibility on dental implants or biomaterials. The GnG composite was constructed by gelatin and hydrogen tetrachloroaurate in presence of reducing agent, sodium borohydrate (NabH 4). The GnG composite was confirmed by UV-VIS spectroscopy and transmission electron microscopy (TEM). A dipping method was used to modify the titanium surface by GnG composite. Surface was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The MC-3T3 E1 cell viability was assessed by trypan blue and the expression of proteins to biocompatibility were analyzed by Western blotting. The GnG composite showed well dispersed character, the strong absorption at 530 nm, roughness, regular crystal and clear C, Na, Cl, P, and Au signals onto titanium. Further, this composite allowed MC-3T3 E1 growth and viability compared to gelatin and pure titanium. It induced ERK activation and the expression of cell adherent molecules, FAK and SPARC, and growth factor, VEGF. However, GnG decreased the level of SAPK/JNK. This shows that GnG composite coated titanium surfaces have a good biocompatibility for osteoblast growth and attachment than in intact by simple and versatile dipping method. Furthermore, it offers good communication between cell and implant surfaces by regulating cell signaling and adherent molecules, which are useful to enhance the biocompatibility of titanium surfaces.

  5. Kinetics studies of the F + HCl → HF + Cl reaction on an accurate potential energy surface

    Science.gov (United States)

    Lu, Dandan; Zhang, Ying; Li, Jun

    2018-02-01

    A full-dimensional electronic ground state potential energy surface for the hydrogen abstraction reaction F + HCl → HF + Cl is developed by using the permutation invariant polynomial neural network approach based on 6509 points computed at the level of CCSD(T)-F12a/AVTZ. Spin-orbit correction is also taken into account at the complete active space self-consistent field level. Theoretical thermal rate coefficients determined by the ring polymer molecular dynamics (RPMD) approach agree well with experiment, validating the accuracy of the PES. Kinetic isotope effect is also investigated.

  6. An experimental approach for measuring surface potential and second crossover energy in insulators

    International Nuclear Information System (INIS)

    Fakhfakh, S; Jbara, O; Rondot, S; Rau, E I; Fakhfakh, Z

    2008-01-01

    The goal of this work is to first measure the second crossover energy E 2S under stationary electron irradiation (charging conditions) and then to show that the charge balance occurs at this beam energy and not at E 2C , the energy deduced from non-charging conditions (short pulse irradiation) as commonly assumed. The experimental procedure is based on simultaneous time dependent measurements of surface potential, leakage and displacement currents. The study is illustrated by the estimate of the real landing energy of primary electrons E L and the second crossover energy E 2S for soda-lime glass

  7. An experimental approach for measuring surface potential and second crossover energy in insulators

    Energy Technology Data Exchange (ETDEWEB)

    Fakhfakh, S; Jbara, O; Rondot, S [UTAP/LASSI, EA 3802 Faculte des Sciences, BP 1039, 51687 Reims Cedex 2 (France); Rau, E I [Institute of Microelectronics Technology of Russian Academy of Science, 142432, Chernogolovka, Moscow District (Russian Federation); Fakhfakh, Z [LaMaCop, Faculte des Sciences, Route Soukra Km 3, BP 802, CP 3018 Sfax (Tunisia)], E-mail: slimfakhfakh@yahoo.fr

    2008-05-21

    The goal of this work is to first measure the second crossover energy E{sub 2S} under stationary electron irradiation (charging conditions) and then to show that the charge balance occurs at this beam energy and not at E{sub 2C}, the energy deduced from non-charging conditions (short pulse irradiation) as commonly assumed. The experimental procedure is based on simultaneous time dependent measurements of surface potential, leakage and displacement currents. The study is illustrated by the estimate of the real landing energy of primary electrons E{sub L} and the second crossover energy E{sub 2S} for soda-lime glass.

  8. A New Potential Energy Surface for N+O2: Is There an NOO Minimum?

    Science.gov (United States)

    Walch, Stephen P.

    1995-01-01

    We report a new calculation of the N+02 potential energy surface using complete active space self-consistent field internally contracted configuration interaction with the Dunning correlation consistent basis sets. The peroxy isomer of N02 is found to be a very shallow minimum separated from NO+O by a barrier of only 0.3 kcal/mol (excluding zero-point effects). The entrance channel barrier height is estimated to be 8.6 kcal/mol for ICCI+Q calculations correlating all but the Ols and N1s electrons with a cc-p VQZ basis set.

  9. Computed Potential Energy Surfaces and Minimum Energy Pathway for Chemical Reactions

    Science.gov (United States)

    Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

    1994-01-01

    Computed potential energy surfaces are often required for computation of such observables as rate constants as a function of temperature, product branching ratios, and other detailed properties. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method with the Dunning correlation consistent basis sets to obtain accurate energetics, gives useful results for a number of chemically important systems. Applications to complex reactions leading to NO and soot formation in hydrocarbon combustion are discussed.

  10. Critical points of the conformational potential energy surface of carbonic acid: H 2CO 3

    Science.gov (United States)

    Janoschek, Rudolf; Csizmadia, Imre G.

    1993-12-01

    The conformational potential energy surface E  E( T1, T2) of H 2CO 3, where T1 is the torsional angle for HO 1CO 2 and T2 is the torsional angle for O 1CO 2H, revealed that the anti—anti conformation is the global minimum. Additional local minima were also found. The next higher energy conformation was the syn—anti conformation, and a degenerate pair of right handed and left handed helical conformations were the highest on the energy scale. The syn—syn conformation turned out to be a transition structure sandwiched between the two helical conformation.

  11. An algorithm to use higher order invariants for modelling potential energy surface of nanoclusters

    Science.gov (United States)

    Jindal, Shweta; Bulusu, Satya S.

    2018-02-01

    In order to fit potential energy surface (PES) of gold nanoclusters, we have integrated bispectrum features with artificial neural network (ANN) learning technique in this work. We have also devised an algorithm for selecting the frequencies that need to be coupled for extracting the phase information between different frequency bands. We have found that higher order invariant like bispectrum is highly efficient in exploring the PES as compared to other invariants. The sensitivity of bispectrum can also be exploited in acting as an order parameter for calculating many thermodynamic properties of nanoclusters.

  12. Potential of surface-eroding poly(ethylene carbonate) for drug delivery to macrophages

    DEFF Research Database (Denmark)

    Bohr, Adam; Water, Jorrit J; Wang, Yingya

    2016-01-01

    Films composed of poly(ethylene carbonate) (PEC), a biodegradable polymer, were compared with poly(lactide-co-glycolide) (PLGA) films loaded with and without the tuberculosis drug rifampicin to study the characteristics and performance of PEC as a potential carrier for controlled drug delivery...... surface erosion (by cholesterol esterase). Drug release studies performed with polymer films indicated a diffusion/erosion dependent delivery behavior for PLGA while an almost zero-order drug release profile was observed from PEC due to the controlled polymer degradation process. When exposed to polymer...... for controlled drug release and could provide superior performance to PLGA for some drug delivery applications including the treatment of macrophage infections....

  13. Potential Energy Surfaces of the Even-Even 230-238 U Isotopes

    Directory of Open Access Journals (Sweden)

    Sohair M. Diab

    2008-07-01

    Full Text Available Nuclear structure of 230-238 U isotopes hav been studied in the frame work of the interacting boson approximation model (IBM-1. The contour plot of the potential energy surfaces, $V(eta,gamma$, shows that all nuclei are deformed and have rotational characters, $SU(3$. Levels energy spectra belonging to the $gsb$, $eta $, $gamma $ bands, electromagnetic transition rates $B(E1$ and $ B(E2$, quadrupole moment $Q_0 $, deformation parameter are $eta_2$ and the strength of the electric monopole transitions $X(E0/E2$ are calculated. The calculated values are compared with the available theoretical and experimental data and show reasonable agreement.

  14. Potential Energy Surfaces of the Even-Even 230-238 U Isotopes

    Directory of Open Access Journals (Sweden)

    Diab S. M.

    2008-07-01

    Full Text Available Nuclear structure of 230 - 238 U isotopes have been studied in the frame work of the in- teracting boson approximation model (IBM-I. The contour plot of the potential energy surfaces, V ( ; , shows that all nuclei are deformed and have rotational char- acters, SU (3 . Levels energy spectra belonging to the gsb , , bands, electromagnetic transition rates B ( E 1 and B ( E 2 , quadrupole moment Q 0 , deformation parameterare 2 and the strength of the electric monopole transitions X ( E 0 =E 2 are calculated. The calculated values are compared with the available theoretical and experimental data and show reasonable agreement.

  15. Modeling Potential Energy Surfaces: From First-Principle Approaches to Empirical Force Fields

    Directory of Open Access Journals (Sweden)

    Pietro Ballone

    2013-12-01

    Full Text Available Explicit or implicit expressions of potential energy surfaces (PES represent the basis of our ability to simulate condensed matter systems, possibly understanding and sometimes predicting their properties by purely computational methods. The paper provides an outline of the major approaches currently used to approximate and represent PESs and contains a brief discussion of what still needs to be achieved. The paper also analyses the relative role of empirical and ab initio methods, which represents a crucial issue affecting the future of modeling in chemical physics and materials science.

  16. Efficient and Adaptive Methods for Computing Accurate Potential Surfaces for Quantum Nuclear Effects: Applications to Hydrogen-Transfer Reactions.

    Science.gov (United States)

    DeGregorio, Nicole; Iyengar, Srinivasan S

    2018-01-09

    We present two sampling measures to gauge critical regions of potential energy surfaces. These sampling measures employ (a) the instantaneous quantum wavepacket density, an approximation to the (b) potential surface, its (c) gradients, and (d) a Shannon information theory based expression that estimates the local entropy associated with the quantum wavepacket. These four criteria together enable a directed sampling of potential surfaces that appears to correctly describe the local oscillation frequencies, or the local Nyquist frequency, of a potential surface. The sampling functions are then utilized to derive a tessellation scheme that discretizes the multidimensional space to enable efficient sampling of potential surfaces. The sampled potential surface is then combined with four different interpolation procedures, namely, (a) local Hermite curve interpolation, (b) low-pass filtered Lagrange interpolation, (c) the monomial symmetrization approximation (MSA) developed by Bowman and co-workers, and (d) a modified Shepard algorithm. The sampling procedure and the fitting schemes are used to compute (a) potential surfaces in highly anharmonic hydrogen-bonded systems and (b) study hydrogen-transfer reactions in biogenic volatile organic compounds (isoprene) where the transferring hydrogen atom is found to demonstrate critical quantum nuclear effects. In the case of isoprene, the algorithm discussed here is used to derive multidimensional potential surfaces along a hydrogen-transfer reaction path to gauge the effect of quantum-nuclear degrees of freedom on the hydrogen-transfer process. Based on the decreased computational effort, facilitated by the optimal sampling of the potential surfaces through the use of sampling functions discussed here, and the accuracy of the associated potential surfaces, we believe the method will find great utility in the study of quantum nuclear dynamics problems, of which application to hydrogen-transfer reactions and hydrogen

  17. Review of singular potential integrals for method of moments solutions of surface integral equations

    Directory of Open Access Journals (Sweden)

    A. Tzoulis

    2004-01-01

    Full Text Available Accurate evaluation of singular potential integrals is essential for successful method of moments (MoM solutions of surface integral equations. In mixed potential formulations for metallic and dielectric scatterers, kernels with 1/R and r1/R singularities must be considered. Several techniques for the treatment of these singularities will be reviewed. The most common approach solves the MoM source integrals analytically for specific observation points, thus regularizing the integral. However, in the case of r1/R a logarithmic singularity remains for which numerical evaluation of the testing integral is still difficult. A recently by Yl¨a-Oijala and Taskinen proposed remedy to this issue is discussed and evaluated within a hybrid finite element – boundary integral technique. Convergence results for the MoM coupling integrals are presented where also higher-order singularity extraction is considered.

  18. Determination of the potential energy surfaces of refrigerant mixtures and their gas transport coefficients

    Directory of Open Access Journals (Sweden)

    Song Bo

    2017-01-01

    Full Text Available In this work, the inversion scheme was used to determine the potential energy surfaces of five polar refrigerant mixtures. The systems studied here are R123-R134a, R123-R142b, R123-R152a, R142b-R134a, and R142b-R152a. The low density transport coefficients of the refrigerant mixtures were calculated from the new invert potentials by the classical kinetic theory. The viscosity coefficient, binary diffusion coefficient, and thermal diffusion factor were computed for the temperature range from 313.15-973.15 K. The agreement with the NIST viscosity data demonstrates that the present calculated values are accurate enough to supplement experimental data over an extended temperature range. Correlations of the transport properties were also provided for the refrigerant mixtures at equimolar ratios.

  19. Diabatic Molecular Orbitals, Potential Energies, and Potential Energy Surface Couplings by the 4-fold Way for Photodissociation of Phenol.

    Science.gov (United States)

    Xu, Xuefei; Yang, Ke R; Truhlar, Donald G

    2013-08-13

    Complete-active-space self-consistent-field (CASSCF) calculations provide useful reference wave functions for configuration interaction or perturbation theory calculations of excited-state potential energy surfaces including dynamical electron correlation. However, the canonical molecular orbitals (MOs) of CASSCF calculations usually have mixed character in regions of strong interaction of two or more electronic states; therefore, they are unsuitable for diabatization using the configurational uniformity approach. Here, CASSCF diabatic MOs for phenol have been obtained by the 4-fold way, and comparison to the CASSCF canonical MOs shows that they are much smoother. Using these smooth CASSCF diabatic MOs, we performed direct diabatization calculations for the three low-lying states ((1)ππ, (1)ππ*, and (1)πσ*) and their diabatic (scalar) couplings at the dynamically correlated multiconfiguration quasidegenerate perturbation theory (MC-QDPT) level. We present calculations along the O-H stretching and C-C-O-H torsion coordinates for the nonadiabatic photodissociation of phenol to the phenoxyl radical and hydrogen atom. The seams of (1)ππ*/(1)πσ* and (1)ππ/(1)πσ* diabatic crossings are plotted as functions of these coordinates. We also present diabatization calculations for displacements along the out-of-plane ring distortion modes 16a and 16b of the phenyl group. The dominant coupling modes of the two conical intersections ((1)ππ*/(1)πσ* and (1)ππ/(1)πσ*) are discussed. The present diabatization method is confirmed to be valid even for significantly distorted ring structures by diabatization calculations along a reaction path connecting the planar equilibrium geometry of phenol to its strongly distorted prefulvenic form. The present work provides insight into the mode specificity of phenol photodissociation and shows that diabatization at the MC-QDPT level employing CASSCF diabatic MOs can be a good starting point for multidimensional dynamics

  20. Potential energy surface of the reaction of imidazole with peroxynitrite: Density functional theory study

    Science.gov (United States)

    Gogonea, Valentin

    This article presents a theoretical investigation of the reaction mechanism of imidazole nitration by peroxynitrite using density functional theory calculations. Understanding this reaction mechanism will help in elucidating the mechanism of guanine nitration by peroxynitrite, which is one of the assumed chemical pathways for damaging DNA in cells. This work focuses on the analysis of the potential energy surface (PES) for this reaction in the gas phase. Calculations were carried out using Hartree-Fock (HF) and density functional theory (DFT) Hamiltonians with double-zeta basis sets ranging from 6-31G(d) to 6-31++G(d,p), and the triple-zeta basis set 6-311G(d). The computational results reveal that the reaction of imidazole with peroxynitrite in gas phase produces the following species: (i) hydroxide ion and 2-nitroimidazole, (ii) hydrogen superoxide ion and 2-nitrosoimidazole, and (iii) water and 2-nitroimidazolide. The rate-determining step is the formation of a short-lived intermediate in which the imidazole C2 carbon is covalently bonded to peroxynitrite nitrogen. Three short-lived intermediates were found in the reaction path. These intermediates are involved in a proton-hopping transport from C2 carbon to the terminal oxygen of the OO moiety of peroxynitrite via the nitroso (ON) oxygen. Both HF and DFT calculations (using the Becke3-Lee-Yang-Parr functional) lead to similar reaction paths for proton transport, but the landscape details of the PES for HF and DFT calculations differ. This investigation shows that the reaction of imidazole with peroxynitrite produces essentially the same types of products (nitro- and nitroso-) as observed experimentally in the reaction of guanine with peroxynitrite, which makes the former reaction a good model to study by computation the essential characteristics of the latter reaction. Nevertheless, the computationally determined activation energy for imidazole nitration by peroxynitrite in the gas phase is 84.1 kcal

  1. Increasing access to modern contraceptives: the potential role of community solidarity through altruistic contributions

    Science.gov (United States)

    2012-01-01

    Background There is an urgent need for universal access to modern contraceptives in Nigeria, to facilitate the achievement of the Millennium Development Goals and other national goals. This study provides information on the potential role of community solidarity in increasing access to contraceptives for the most-poor people through exploration of the role of altruism by determining level of altruistic willingness to pay (WTP) for modern contraceptives across different geographic contexts in Nigeria. Methods It was a cross-sectional national survey which took place in six states spread across the six-geopolitical zones of the country. In each state, an urban and a rural area were selected for the study, giving a total of 6 urban and 6 rural sites. A pre-tested interviewer-administered questionnaire was used to collect information from at least 720 randomly selected householders from each state. The targeted respondent in a household was a female primary care giver of child bearing age (usually the wives), or in her absence, another female household member of child bearing age. A scenario on altruistic WTP was presented before the value was elicited using a binary with open-ended follow-up question format. Test of validity of elicited altruistic WTP was undertaken using Tobit regression. Findings More than 50 % of the respondents across all the states were willing to contribute some money so that the very poor would be provided with modern contraceptives. The average amount of money that people were willing to contribute annually was 650 Naira (US$4.5). Mean altruistic WTP differed across SES quintiles and urban-rural divide (p solidarity to ensure that the very poor benefit from modern contraceptives and assure universal coverage with modern contraceptives. The factors that determine altruistic WTP should be harnessed to ensure that altruistic contributions are actually made. The challenge will be how to collect and pool the altruistic contributions for

  2. A nanostructured surface increases friction exponentially at the solid-gas interface

    Science.gov (United States)

    Phani, Arindam; Putkaradze, Vakhtang; Hawk, John E.; Prashanthi, Kovur; Thundat, Thomas

    2016-09-01

    According to Stokes’ law, a moving solid surface experiences viscous drag that is linearly related to its velocity and the viscosity of the medium. The viscous interactions result in dissipation that is known to scale as the square root of the kinematic viscosity times the density of the gas. We observed that when an oscillating surface is modified with nanostructures, the experimentally measured dissipation shows an exponential dependence on kinematic viscosity. The surface nanostructures alter solid-gas interplay greatly, amplifying the dissipation response exponentially for even minute variations in viscosity. Nanostructured resonator thus allows discrimination of otherwise narrow range of gaseous viscosity making dissipation an ideal parameter for analysis of a gaseous media. We attribute the observed exponential enhancement to the stochastic nature of interactions of many coupled nanostructures with the gas media.

  3. Exercise body surface potential mapping in single and multiple coronary artery disease

    International Nuclear Information System (INIS)

    Montague, T.J.; Witkowski, F.X.; Miller, R.M.; Johnstone, D.E.; MacKenzie, R.B.; Spencer, C.A.; Horacek, B.M.

    1990-01-01

    Body surface ST integral maps were recorded in 36 coronary artery disease (CAD) patients at: rest; peak, angina-limited exercise; and, 1 and 5 min of recovery. They were compared to maps of 15 CAD patients who exercised to fatigue, without angina, and eight normal subjects. Peak exercise heart rates were similar (NS) in all groups. With exercise angina, patients with two and three vessel CAD had significantly (p less than 0.05) greater decrease in the body surface sum of ST integral values than patients with single vessel CAD. CAD patients with exercise fatigue, in the absence of angina, had decreased ST integrals similar (NS) to patients with single vessel CAD who manifested angina and the normal control subjects. There was, however, considerable overlap among individuals; some patients with single vessel CAD had as much exercise ST integral decrease as patients with three vessel CAD. All CAD patients had persistent ST integral decreases at 5 min of recovery and there was a direct correlation of the recovery and peak exercise ST changes. Exercise ST changes correlated, as well, with quantitative CAD angiographic scores, but not with thallium perfusion scores. These data suggest exercise ST integral body surface mapping allows quantitation of myocardium at ischemic risk in patients with CAD, irrespective of the presence or absence of ischemic symptoms during exercise. A major potential application of this technique is selection of CAD therapy guided by quantitative assessment of ischemic myocardial risk

  4. Do surfaces of positive electrostatic potential on different halogen derivatives in molecules attract? like attracting like!

    Science.gov (United States)

    Varadwaj, Arpita; Varadwaj, Pradeep R; Yamashita, Koichi

    2018-03-15

    Coulomb's law states that like charges repel, and unlike charges attract. However, it has recently been theoretically revealed that two similarly charged conducting spheres will almost always attract each other when both are in close proximity. Using multiscale first principles calculations, we illustrate practical examples of several intermolecular complexes that are formed by the consequences of attraction between positive atomic sites of similar or dissimilar electrostatic surface potential on interacting molecules. The results of the quantum theory of atoms in molecules and symmetry adapted perturbation theory support the attraction between the positive sites, characterizing the F•••X (X = F, Cl, Br) intermolecular interactions in a series of 20 binary complexes as closed-shell type, although the molecular electrostatic surface potential approach does not (a failure!). Dispersion that has an r -6 dependence, where r is the equilibrium distance of separation, is found to be the sole driving force pushing the two positive sites to attract. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Ab Initio Potential Energy Surfaces and the Calculation of Accurate Vibrational Frequencies

    Science.gov (United States)

    Lee, Timothy J.; Dateo, Christopher E.; Martin, Jan M. L.; Taylor, Peter R.; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    Due to advances in quantum mechanical methods over the last few years, it is now possible to determine ab initio potential energy surfaces in which fundamental vibrational frequencies are accurate to within plus or minus 8 cm(exp -1) on average, and molecular bond distances are accurate to within plus or minus 0.001-0.003 Angstroms, depending on the nature of the bond. That is, the potential energy surfaces have not been scaled or empirically adjusted in any way, showing that theoretical methods have progressed to the point of being useful in analyzing spectra that are not from a tightly controlled laboratory environment, such as vibrational spectra from the interstellar medium. Some recent examples demonstrating this accuracy will be presented and discussed. These include the HNO, CH4, C2H4, and ClCN molecules. The HNO molecule is interesting due to the very large H-N anharmonicity, while ClCN has a very large Fermi resonance. The ab initio studies for the CH4 and C2H4 molecules present the first accurate full quartic force fields of any kind (i.e., whether theoretical or empirical) for a five-atom and six-atom system, respectively.

  6. On the potential application of land surface models for drought monitoring in China

    Science.gov (United States)

    Zhang, Liang; Zhang, Huqiang; Zhang, Qiang; Li, Yaohui; Zhao, Jianhua

    2017-05-01

    The potential of using land surface models (LSMs) to monitor near-real-time drought has not been fully assessed in China yet. In this study, we analyze the performance of such a system with a land surface model (LSM) named the Australian Community Atmosphere Biosphere Land Exchange model (CABLE). The meteorological forcing datasets based on reanalysis products and corrected by observational data have been extended to near-real time for semi-operational trial. CABLE-simulated soil moisture (SM) anomalies are used to characterize drought spatial and temporal evolutions. One outstanding feature in our analysis is that with the same meteorological data, we have calculated a range of drought indices including Standardized Precipitation Index (SPI), Standardized Precipitation-Evapotranspiration Index (SPEI), Palmer Drought Severity Index (PDSI). We have assessed the similarity among these indices against observed SM over a number of regions in China. While precipitation is the dominant factor in the drought development, relationships between precipitation, evaporation, and soil moisture anomalies vary significantly under different climate regimes, resulting in different characteristics of droughts in China. The LSM-based trial system is further evaluated for the 1997/1998 drought in northern China and 2009/2010 drought in southwestern China. The system can capture the severities and temporal and spatial evolutions of these drought events well. The advantage of using a LSM-based drought monitoring system is further demonstrated by its potential to monitor other consequences of drought impacts in a more physically consistent manner.

  7. Phonon-mediated decay of an atom in a surface-induced potential

    International Nuclear Information System (INIS)

    Kien, Fam Le; Hakuta, K.; Dutta Gupta, S.

    2007-01-01

    We study phonon-mediated transitions between translational levels of an atom in a surface-induced potential. We present a general master equation governing the dynamics of the translational states of the atom. In the framework of the Debye model, we derive compact expressions for the rates for both upward and downward transitions. Numerical calculations for the transition rates are performed for a deep silica-induced potential allowing for a large number of bound levels as well as free states of a cesium atom. The total absorption rate is shown to be determined mainly by the bound-to-bound transitions for deep bound levels and by bound-to-free transitions for shallow bound levels. Moreover, the phonon emission and absorption processes can be orders of magnitude larger for deep bound levels as compared to the shallow bound ones. We also study various types of transitions from free states. We show that, for thermal atomic cesium with a temperature in the range from 100 μK to 400 μK in the vicinity of a silica surface with a temperature of 300 K, the adsorption (free-to-bound decay) rate is about two times larger than the heating (free-to-free upward decay) rate, while the cooling (free-to-free downward decay) rate is negligible

  8. The remineralization potential of cocoa (Theobroma cacao) bean extract to increase the enamel micro hardness

    OpenAIRE

    Sulistianingsih Sulistianingsih; Irmaleny Irmaleny; Opik Taofik Hidayat

    2017-01-01

    Introduction: Remineralization is the process of returning mineral ions into a hydroxyapatite structure characterized by mineral deposition on the enamel surface. The presence of mineral deposition would affect the micro hardness of tooth enamel. The use of fluorine as remineralization agent with side effects such as fluorosis. Cocoa bean extract contains theobromin that can be used as an alternative remineralization ingredients. The objectives was to determine micro hardness email after remi...

  9. A Comparison of Streaming and Microelectrophoresis Methods for Obtaining the zeta Potential of Granular Porous Media Surfaces.

    Science.gov (United States)

    Johnson

    1999-01-01

    The electrokinetic behavior of granular quartz sand in aqueous solution is investigated by both microelectrophoresis and streaming potential methods. zeta potentials of surfaces composed of granular quartz obtained via streaming potential methods are compared to electrophoretic mobility zeta potential values of colloid-sized quartz fragments. The zeta values generated by these alternate methods are in close agreement over a wide pH range and electrolyte concentrations spanning several orders of magnitude. Streaming measurements performed on chemically heterogeneous mixtures of physically homogeneous sand are shown to obey a simple mixing model based on the surface area-weighted average of the streaming potentials associated with the individual end members. These experimental results support the applicability of the streaming potential method as a means of determining the zeta potential of granular porous media surfaces. Copyright 1999 Academic Press.

  10. Increased hand washing reduces influenza virus surface contamination in Bangkok households, 2009-2010.

    Science.gov (United States)

    Levy, Jens W; Suntarattiwong, Piyarat; Simmerman, James M; Jarman, Richard G; Johnson, Kara; Olsen, Sonja J; Chotpitayasunondh, Tawee

    2014-01-01

    Within a hand-washing clinical trial, we evaluated factors associated with fomite contamination in households with an influenza-infected child. Influenza virus RNA contamination was higher in households with low absolute humidity and in control households, suggesting that hand washing reduces surface contamination. © 2013 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

  11. Increased hand washing reduces influenza virus surface contamination in Bangkok households, 2009–2010

    Science.gov (United States)

    Levy, Jens W; Suntarattiwong, Piyarat; Simmerman, James M; Jarman, Richard G; Johnson, Kara; Olsen, Sonja J; Chotpitayasunondh, Tawee

    2014-01-01

    Within a hand-washing clinical trial, we evaluated factors associated with fomite contamination in households with an influenza-infected child. Influenza virus RNA contamination was higher in households with low absolute humidity and in control households, suggesting that hand washing reduces surface contamination. PMID:24373290

  12. Reduced PDZ Interactions of Rescued ΔF508CFTR Increases Its Cell Surface Mobility*

    Science.gov (United States)

    Valentine, Cathleen D.; Lukacs, Gergely L.; Verkman, Alan S.; Haggie, Peter M.

    2012-01-01

    Deletion of phenylalanine 508 (ΔF508) in the cystic fibrosis transmembrane conductance regulator (CFTR) plasma membrane chloride channel is the most common cause of cystic fibrosis (CF). Though several maneuvers can rescue endoplasmic reticulum-retained ΔF508CFTR and promote its trafficking to the plasma membrane, rescued ΔF508CFTR remains susceptible to quality control mechanisms that lead to accelerated endocytosis, ubiquitination, and lysosomal degradation. To investigate the role of scaffold protein interactions in rescued ΔF508CFTR surface instability, the plasma membrane mobility of ΔF508CFTR was measured in live cells by quantum dot single particle tracking. Following rescue by low temperature, chemical correctors, thapsigargin, or overexpression of GRASP55, ΔF508CFTR diffusion was more rapid than that of wild-type CFTR because of reduced interactions with PDZ domain-containing scaffold proteins. Knock-down of the plasma membrane quality control proteins CHIP and Hsc70 partially restored ΔF508CFTR-scaffold association. Quantitative comparisons of CFTR cell surface diffusion and endocytosis kinetics suggested an association between reduced scaffold binding and CFTR internalization. Our surface diffusion measurements in live cells indicate defective scaffold interactions of rescued ΔF508CFTR at the cell surface, which may contribute to its defective peripheral processing. PMID:23115232

  13. Future climate warming increases Greenland ice sheet surface mass balance variability

    NARCIS (Netherlands)

    Fyke, J.G.; Vizcaino, M.; Lipscomb, W.; Price, S.

    2014-01-01

    The integrated surface mass balance (SMB) of the Greenland ice sheet (GrIS) has large interannual variability. Long-term future changes to this variability will affect GrIS dynamics, freshwater fluxes, regional oceanography, and detection of changes in ice volume trends. Here we analyze a simulated

  14. Quantification of acute vocal fold epithelial surface damage with increasing time and magnitude doses of vibration exposure.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Kojima

    Full Text Available Because the vocal folds undergo repeated trauma during continuous cycles of vibration, the epithelium is routinely susceptible to damage during phonation. Excessive and prolonged vibration exposure is considered a significant predisposing factor in the development of vocal fold pathology. The purpose of the present study was to quantify the extent of epithelial surface damage following increased time and magnitude doses of vibration exposure using an in vivo rabbit phonation model. Forty-five New Zealand white breeder rabbits were randomized to nine groups and received varying phonation time-doses (30, 60, or 120 minutes and magnitude-doses (control, modal intensity phonation, or raised intensity phonation of vibration exposure. Scanning electron microscopy and transmission electron microscopy was used to quantify the degree of epithelial surface damage. Results revealed a significant reduction in microprojection density, microprojection height, and depth of the epithelial surface with increasing time and phonation magnitudes doses, signifying increased epithelial surface damage risk with excessive and prolonged vibration exposure. Destruction to the epithelial cell surface may provide significant insight into the disruption of cell function following prolonged vibration exposure. One important goal achieved in the present study was the quantification of epithelial surface damage using objective imaging criteria. These data provide an important foundation for future studies of long-term tissue recovery from excessive and prolonged vibration exposure.

  15. Surface-wave potential for triggering tectonic (nonvolcanic) tremor-corrected

    Science.gov (United States)

    Hill, David P.

    2012-01-01

    Source processes commonly posed to explain instances of remote dynamic triggering of tectonic (nonvolcanic) tremor by surface waves include frictional failure and various modes of fluid activation. The relative potential for Love- and Rayleigh-wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike-slip faults under the Coulomb-Griffith failure criteria as a function of incidence angle are anticorrelated over the 15- to 30-km-depth range that hosts tectonic tremor. Love-wave potential is high for strike-parallel incidence on low-angle reverse faults and null for strike-normal incidence; the opposite holds for Rayleigh waves. Love-wave potential is high for both strike-parallel and strike-normal incidence on vertical, strike-slip faults and minimal for ~45° incidence angles. The opposite holds for Rayleigh waves. This pattern is consistent with documented instances of tremor triggered by Love waves incident on the Cascadia megathrust and the San Andreas fault (SAF) in central California resulting from shear failure on weak faults (apparent friction is μ* ≤ 0:2). Documented instances of tremor triggered by surface waves with strike-parallel incidence along the Nankai megathrust beneath Shikoku, Japan, however, are associated primarily with Rayleigh waves. This is consistent with the tremor bursts resulting from mixed-mode failure (crack opening and shear failure) facilitated by near-lithostatic ambient pore pressure, low differential stress, with a moderate friction coefficient (μ ~ 0:6) on the Nankai subduction interface. Rayleigh-wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process, except perhaps for an indirect role on the SAF in sustaining tremor into the Rayleigh-wave coda that was initially triggered by Love waves.

  16. Mapping the Diffusion Potential of a Reconstructed Au(111) Surface at Nanometer Scale with 2D Molecular Gas

    International Nuclear Information System (INIS)

    Yan Shi-Chao; Xie Nan; Gong Hui-Qi; Guo Yang; Shan Xin-Yan; Lu Xing-Hua; Sun Qian

    2012-01-01

    The adsorption and diffusion behaviors of benzene molecules on an Au(111) surface are investigated by low-temperature scanning tunneling microscopy. A herringbone surface reconstruction of the Au(111) surface is imaged with atomic resolution, and significantly different behaviors are observed for benzene molecules adsorbed on step edges and terraces. The electric field induced modification in the molecular diffusion potential is revealed with a 2D molecular gas model, and a new method is developed to map the diffusion potential over the reconstructed Au(111) surface at the nanometer scale. (condensed matter: structure, mechanical and thermal properties)

  17. Evaluation of a natural speech based informational inquiry system as a potential means to increase transit utilization.

    Science.gov (United States)

    2013-05-01

    This project proposed to explore the potential of a user friendly, natural speech based : information inquiry application as one means of increasing public transit utilization. It suggested : that a key challenge to expanding transit ridership isto e...

  18. Aging Adults Learning New Avocations: Potential Increases in Activity among Educated Baby-Boomers

    Science.gov (United States)

    Johnson, Marcus Lee; Bungum, Timothy

    2008-01-01

    The potential benefits, drawbacks, and preferences of activity (both physical and nonphysical) among Baby-Boomers were the foci of this study. This study included 56 survey participants and 5 interviewees. Descriptive statistics illustrated a preference towards low impact physical activity and cognitively enriching nonphysical activities. Time…

  19. Increased Paracrine Immunomodulatory Potential of Mesenchymal Stromal Cells in Three-Dimensional Culture

    DEFF Research Database (Denmark)

    Follin, Bjarke; Juhl, Morten; Cohen, Smadar

    2016-01-01

    Mesenchymal stromal/stem cells (MSCs) have been investigated extensively through the past years, proving to have great clinical therapeutic potential. In vitro cultivation of MSCs in three-dimensional (3D) culture systems, such as scaffolds, hydrogels, or spheroids, have recently gained attention...

  20. Analysis of Underground Storage Tanks System Materials to Increased Leak Potential Associated with E15 Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kass, Michael D [ORNL; Theiss, Timothy J [ORNL; Janke, Christopher James [ORNL; Pawel, Steven J [ORNL

    2012-07-01

    The Energy Independence and Security Act (EISA) of 2007 was enacted by Congress to move the nation toward increased energy independence by increasing the production of renewable fuels to meet its transportation energy needs. The law establishes a new renewable fuel standard (RFS) that requires the nation to use 36 billion gallons annually (2.3 million barrels per day) of renewable fuel in its vehicles by 2022. Ethanol is the most widely used renewable fuel in the US, and its production has grown dramatically over the past decade. According to EISA and RFS, ethanol (produced from corn as well as cellulosic feedstocks) will make up the vast majority of the new renewable fuel requirements. However, ethanol use limited to E10 and E85 (in the case of flex fuel vehicles or FFVs) will not meet this target. Even if all of the E0 gasoline dispensers in the country were converted to E10, such sales would represent only about 15 billion gallons per year. If 15% ethanol, rather than 10% were used, the potential would be up to 22 billion gallons. The vast majority of ethanol used in the United States is blended with gasoline to create E10, that is, gasoline with up to 10% ethanol. The remaining ethanol is sold in the form of E85, a gasoline blend with as much as 85% ethanol that can only be used in FFVs. Although DOE remains committed to expanding the E85 infrastructure, that market will not be able to absorb projected volumes of ethanol in the near term. Given this reality, DOE and others have begun assessing the viability of using intermediate ethanol blends as one way to transition to higher volumes of ethanol. In October of 2010, the EPA granted a partial waiver to the Clean Air Act allowing the use of fuel that contains up to 15% ethanol for the model year 2007 and newer light-duty motor vehicles. This waiver represents the first of a number of actions that are needed to move toward the commercialization of E15 gasoline blends. On January 2011, this waiver was expanded to

  1. An Investigation of Student Response to a Potential Tuition Cap Increase at Casper College

    Science.gov (United States)

    Davis, Elizabeth; Aitchison, Thomas; Allen, Eric; Gomez, Carrie; Laird, Sheree; Raczynska, Kaja

    2015-01-01

    Wyoming Community College Commission policy currently states any student enrolled for more than 12 credit hours will be charged tuition for only 12 credit hours. This policy is referred to as the tuition cap. In November 2010, the commission discussed increasing the tuition cap to 15 credits. An increase from 12 to 15 credits would have…

  2. Colloid properties of hydrophobic modified alginate: Surface tension, ζ-potential, viscosity and emulsification.

    Science.gov (United States)

    Wu, Zongmei; Wu, Jie; Zhang, Ruling; Yuan, Shichao; Lu, Qingliang; Yu, Yueqin

    2018-02-01

    Micelle properties of hydrophobic modified alginate (HM-alginate) in various dispersion media have been studied by surface tension, ζ-potential, and viscosity measurements. Effect of salt on micelle properties showed that the presence of counter ion weakened the repulsive interaction between surfactant ions, decreased the critical micelle concentration (CMC) value of the HM-alginate, reduced the effective volume dimensions of HM-alginate and hence viscosity, which coincide with the corresponding ζ-potential values. Soy oil-in-water emulsions, stabilized solely by HM-alginate, were produced in high speed homogenization conditions and their stability properties were studied by visual inspection, optical microscopy and droplet size measurements. The results showed that emulsions (oil-water ratio was 1:7) containing 15mg/mL HM-alginate presented better stability during 15days storage, which stating clearly that HM-alginate is an effective emulsifier to stabilize oil-in-water emulsions. The herein presented homogeneous method for preparation of emulsion has the potential to be used in food industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Using Metal-Multilayer-Dielectric Structure to Increase Sensitivity of Surface Plasmon Resonance Sensor

    Science.gov (United States)

    Ilchenko, Svitlana G.; Lymarenko, Ruslan A.; Taranenko, Victor B.

    2017-04-01

    We propose using a specially designed metal-multilayer-dielectric structure deposited on glass substrate to enhance the evanescent field and improve the sensitivity of the surface plasmon resonance sensor. The proposed structure supports both hybrid plasmonic transverse magnetic modes and conventional waveguide transverse electric modes. We show numerically the significant enhancement of the evanescent field and improvement of the sensitivity for the waveguide transverse electric mode.

  4. Management of Surface Drying Temperature to Increase Antioxidant Capacity of Thyme Leaf Extracts (Thymus vulgaris L.)

    OpenAIRE

    RODRIGUEZ CORTINA, JADER; Melo, E.C.; Mulet Pons, Antonio; Bon Corbín, José

    2014-01-01

    [EN] Thyme leaves are an important source of essential oils with antioxidant activity; these compounds are located in trichomes on the leaf surface. The drying conditions affect not only the drying time but also the antioxidant activity. In the literature, a drying temperature of 70 ºC appears to be the best for drying thyme leaves according to their antioxidant capacity. Considering drying periods at different temperature also could be quality beneficial. From these considerations, the goal ...

  5. Coating polypropylene surfaces with protease weakens the adhesion and increases the dispersion of Candida albicans cells.

    Science.gov (United States)

    Andreani, Eugenio Spadoni; Villa, Federica; Cappitelli, Francesca; Krasowska, Anna; Biniarz, Piotr; Łukaszewicz, Marcin; Secundo, Francesco

    2017-03-01

    To investigate the ability of the proteases, subtilisin and α-chymotrypsin (aCT), to inhibit the adhesion of Candida albicans biofilm to a polypropylene surface. The proteases were immobilized on plasma-treated polypropylene by covalently linking them with either glutaraldehyde (GA) or N'-diisopropylcarbodiimide (DIC) and N-hydroxysuccinimide (NHS). The immobilization did not negatively affect the enzyme activity and in the case of subtilisin, the activity was up to 640% higher than that of the free enzyme when using N-acetyl phenylalanine ethyl ester as the substrate. The efficacies against biofilm dispersal for the GA-linked SubC and aCT coatings were 41 and 55% higher than the control (polypropylene coated with only GA), respectively, whereas no effect was observed with enzymes immobilized with DIC and NHS. The higher dispersion efficacy observed for the proteases immobilized with GA could be both steric (proper orientation of the active site) and dynamic (higher protein mobility/flexibility). Proteases immobilized on a polypropylene surface reduced the adhesion of C. albicans biofilms and therefore may be useful in developing anti-biofilm surfaces based on non-toxic molecules and sustainable strategies.

  6. Potential health effects of climatic change: Effects of increased ultraviolet radiation on man

    International Nuclear Information System (INIS)

    Urbach, F.

    1991-01-01

    There is scientific evidence that stratospheric ozone concentration has declined over the Northern Hemisphere in the past 20 years, and projections based on various assumption s about future release of chlorofluorocarbon gases and other contaminants suggest that this decline will continue into the next century. The effects on human health secondary to increase in biologically effective ultraviolet radiation are expected to consist of increases in nonmelanoma skin cancer and malignant melanoma of the skin, possible alteration of immune response, and development of lens cataracts. The recent and projected increases in skin cancer and changes in human immune responses are discussed. 19 refs

  7. Surface modification techniques for increased corrosion tolerance of zirconium fuel cladding

    Science.gov (United States)

    Carr, James Patrick, IV

    Corrosion is a major issue in applications involving materials in normal and severe environments, especially when it involves corrosive fluids, high temperatures, and radiation. Left unaddressed, corrosion can lead to catastrophic failures, resulting in economic and environmental liabilities. In nuclear applications, where metals and alloys, such as steel and zirconium, are extensively employed inside and outside of the nuclear reactor, corrosion accelerated by high temperatures, neutron radiation, and corrosive atmospheres, corrosion becomes even more concerning. The objectives of this research are to study and develop surface modification techniques to protect zirconium cladding by the incorporation of a specific barrier coating, and to understand the issues related to the compatibility of the coatings examined in this work. The final goal of this study is to recommend a coating and process that can be scaled-up for the consideration of manufacturing and economic limits. This dissertation study builds on previous accident tolerant fuel cladding research, but is unique in that advanced corrosion methods are tested and considerations for implementation by industry are practiced and discussed. This work will introduce unique studies involving the materials and methods for accident tolerant fuel cladding research by developing, demonstrating, and considering materials and processes for modifying the surface of zircaloy fuel cladding. This innovative research suggests that improvements in the technique to modify the surface of zirconium fuel cladding are likely. Three elements selected for the investigation of their compatibility on zircaloy fuel cladding are aluminum, silicon, and chromium. These materials are also currently being investigated at other labs as alternate alloys and coatings for accident tolerant fuel cladding. This dissertation also investigates the compatibility of these three elements as surface modifiers, by comparing their microstructural and

  8. Increasing organ donation rates by revealing recipient details to families of potential donors.

    Science.gov (United States)

    Shaw, David; Gardiner, Dale

    2018-02-01

    Many families refuse to consent to donation from their deceased relatives or over-rule the consent given before death by the patient, but giving families more information about the potential recipients of organs could reduce refusal rates. In this paper, we analyse arguments for and against doing so, and conclude that this strategy should be attempted. While it would be impractical and possibly unethical to give details of actual potential recipients, generic, realistic information about the people who could benefit from organs should be provided to families before they make a decision about donation or attempt to over-rule it. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  9. Potential Bacterial Consortium to Increase the Effectiveness of Beer Wastewater Treatment

    OpenAIRE

    Putu Nia Anggraeni; Ida Bagus Wayan Gunam; Retno Kawuri

    2014-01-01

    The main objective of this research is to determine the effectiveness of microbial consortia in beer wastewater treatment. The research was initiated with the isolation of soil microbial consortium that has been contaminated by beer waste water, followed by the selection of the best potential microbial beer wastewater treatment. At the end, the selection of the best microbial consortium was tested in beer wastewater treatment based on pollutant parameters namely biochemical oxygen demand (BOD...

  10. The Potential for Energy Storage to Provide Peaking Capacity in California Under Increased Penetration of Solar Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, Paul L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Margolis, Robert M [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-03-14

    In this report, we examine the potential for replacing conventional peaking capacity in California with energy storage, including analysis of the changing technical potential with increased storage deployment and the effect of PV deployment. We examine nine years of historic load data, a range of storage durations (2-8 hours), and a range of PV penetration levels (0%-30%). We demonstrate how PV increases the ability of storage to reduce peak net demand. In the scenarios analyzed, the expected penetration of PV in California in 2020 could more than double the potential for 4-hour energy storage to provide capacity services.

  11. Ab initio potential energy surfaces and quantum dynamics for polyatomic bimolecular reactions.

    Science.gov (United States)

    Fu, Bina; Zhang, Donghui

    2018-03-26

    There has been great progress in the development of potential energy surfaces (PESs) and quantum dynamics calculations in the gas phase. The establishment of fitting procedure for highly accurate PESs and new developments in quantum reactive scattering on reliable PESs allow accurate characterization of reaction dynamics beyond triatomic systems. This review will give the recent development in our group in constructing ab initio PESs based on the neural networks, and the time-dependent wave packet calculations for bimolecular reactions beyond three atoms. Bimolecular reactions of current interest to the community, namely, OH+H2, H+H2O, OH+CO, H+CH4 and Cl+CH4 are focused on. Quantum mechanical characterization of these reactions uncovers interesting dynamical phenomena with an unprecedented level of sophistication, and has greatly advanced our understanding of polyatomic reaction dynamics.

  12. Implementation and interpretation of surface potential decay measurements on corona-charged non-woven fabrics

    International Nuclear Information System (INIS)

    Tabti, B; Antoniu, A; Plopeanu, M; Dascalescu, L; Yahiaoui, B; Bendahmane, B

    2011-01-01

    The aim of this paper is to discuss the peculiarities of the surface potential decay (SPD) curves obtained for certain non-woven media. The experiments were performed on samples of non-woven poly-propylene (PP) sheets, which are typically employed in the construction of air filters for heat, ventilation and air conditioning. The samples were in contact with a grounded plane, in order to: (1) ensure better charging and measurement reproducibility; (2) simulate the worst situation of practical interest. They were charged using either a high-voltage wire-type dual electrode or a triode-type electrode arrangement. The aspect of the SPD curves depends on the electrode configuration. When the electric field is strong enough, it can activate charge injection at the insulator-metal interface and extrinsic conduction.

  13. Evaluation of the potential for surface faulting at TA-63. Final report

    International Nuclear Information System (INIS)

    Kolbe, T.; Sawyer, J.; Springer, J.; Olig, S.; Hemphill-Haley, M.; Wong, I.; Reneau, S.

    1995-01-01

    This report describes an investigation of the potential for surface faulting at the proposed sites for the Radioactive Liquid Waste Treatment Facility (RL)WF) and the Hazardous Waste Treatment Facility at TA-63 and TA-52 (hereafter TA-63), Los Alamos National Laboratory (LANL). This study was performed by Woodward-Clyde Federal Services (WCFS) at the request of the LANL. The projections of both the Guaje Mountain and Rendija Canyon faults are mapped in the vicinity of TA-63. Based on results obtained in the ongoing Seismic Hazard Evaluation Program of the LANL, displacement may have occurred on both the Guaje Mountain and Rendija Canyon faults in the past 11,000 years (Holocene time). Thus, in accordance with US Department of Energy (DOE) Orders and Standards for seismic hazards evaluations and the US Environmental Protection Agency (EPA) Resource Conservation and Recovery Act (RCRA) Regulations for seismic standard requirements, a geologic study of the proposed TA-63 site was conducted

  14. Interaction of C2H with molecular hydrogen: Ab initio potential energy surface and scattering calculations

    Science.gov (United States)

    Dagdigian, Paul J.

    2018-01-01

    The potential energy surface (PES) describing the interaction of the ethynyl (C2H) radical in its ground X˜ 2Σ+ electronic state with molecular hydrogen has been computed through restricted coupled cluster calculations including single, double, and (perturbative) triple excitations [RCCSD(T)], with the assumption of fixed molecular geometries. The computed points were fit to an analytical form suitable for time-independent quantum scattering calculations of rotationally inelastic cross sections and rate constants. A representative set of energy dependent state-to-state cross sections is presented and discussed. The PES and cross sections for collisions of H2(j = 0) are compared with a previous study [F. Najar et al., Chem. Phys. Lett. 614, 251 (2014)] of collisions of C2H with H2 treated as a spherical collision partner. Good agreement is found between the two sets of calculations when the H2 molecule in the present calculation is spherically averaged.

  15. Implementation and interpretation of surface potential decay measurements on corona-charged non-woven fabrics

    Science.gov (United States)

    Tabti, B.; Antoniu, A.; Plopeanu, M.; Yahiaoui, B.; Bendahmane, B.; Dascalescu, L.

    2011-06-01

    The aim of this paper is to discuss the peculiarities of the surface potential decay (SPD) curves obtained for certain non-woven media. The experiments were performed on samples of non-woven poly-propylene (PP) sheets, which are typically employed in the construction of air filters for heat, ventilation and air conditioning. The samples were in contact with a grounded plane, in order to: (1) ensure better charging and measurement reproducibility; (2) simulate the worst situation of practical interest. They were charged using either a high-voltage wire-type dual electrode or a triode-type electrode arrangement. The aspect of the SPD curves depends on the electrode configuration. When the electric field is strong enough, it can activate charge injection at the insulator-metal interface and extrinsic conduction.

  16. Ab initio potential energy surface and vibration-rotation energy levels of beryllium monohydroxide.

    Science.gov (United States)

    Koput, Jacek

    2017-01-05

    The accurate potential energy surface of beryllium monohydroxide, BeOH, in its ground electronic state X 2A' has been determined from ab initio calculations using the coupled-cluster approach in conjunction with the correlation-consistent core-valence basis sets up to septuple-zeta quality. The higher-order electron correlation, scalar relativistic, and adiabatic effects were taken into account. The BeOH molecule was confirmed to be bent at equilibrium, with the BeOH angle of 141.2° and the barrier to linearity of 129 cm -1 . The vibration-rotation energy levels of the BeOH and BeOD isotopologues were predicted using a variational approach and compared with recent experimental data. The results can be useful in a further analysis of high-resolution vibration-rotation spectra of these interesting species. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  17. Ab initio potential energy surface and vibration-rotation energy levels of sulfur dioxide.

    Science.gov (United States)

    Koput, Jacek

    2017-05-05

    An accurate potential energy surface of sulfur dioxide, SO 2 , in its ground electronic state X∼ 1A1 has been determined from ab initio calculations using the coupled-cluster approach in conjunction with the correlation-consistent basis sets up to septuple-zeta quality. The results obtained with the conventional and explicitly correlated coupled-cluster methods are compared. The role of the core-electron correlation, higher-order valence-electron correlation, scalar relativistic, and adiabatic effects in determining the structure and dynamics of the SO 2 molecule is discussed. The vibration-rotation energy levels of the 32 SO 2 and 34 SO 2 isotopologues were predicted using a variational approach. It was shown that the inclusion of the aforementioned effects was mandatory to attain the "spectroscopic" accuracy. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. Flumazenil decreases surface expression of α4β2δ GABAA receptors by increasing the rate of receptor internalization.

    Science.gov (United States)

    Kuver, Aarti; Smith, Sheryl S

    2016-01-01

    Increases in expression of α4βδ GABAA receptors (GABARs), triggered by fluctuations in the neurosteroid THP (3α-OH-5α[β]-pregnan-20-one), are associated with changes in mood and cognition. We tested whether α4βδ trafficking and surface expression would be altered by in vitro exposure to flumazenil, a benzodiazepine ligand which reduces α4βδ expression in vivo. We first determined that flumazenil (100 nM-100 μM, IC50=∼1 μM) acted as a negative modulator, reducing GABA (10 μM)-gated current in the presence of 100 nM THP (to increase receptor efficacy), assessed with whole cell patch clamp recordings of recombinant α4β2δ expressed in HEK-293 cells. Surface expression of recombinant α4β2δ receptors was detected using a 3XFLAG reporter at the C-terminus of α4 (α4F) using confocal immunocytochemical techniques following 48 h exposure of cells to GABA (10 μM)+THP (100 nM). Flumazenil (10 μM) decreased surface expression of α4F by ∼60%, while increasing its intracellular accumulation, after 48 h. Reduced surface expression of α4β2δ after flumazenil treatment was confirmed by decreases in the current responses to 100 nM of the GABA agonist gaboxadol. Flumazenil-induced decreases in surface expression of α4β2δ were prevented by the dynamin blocker, dynasore, and by leupeptin, which blocks lysosomal enzymes, suggesting that flumazenil is acting to increase endocytosis and lysosomal degradation of the receptor. Flumazenil increased the rate of receptor removal from the cell surface by 2-fold, assessed using botulinum toxin B to block insertion of new receptors. These findings may suggest new therapeutic strategies for regulation of α4β2δ expression using flumazenil. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Ventricular filling slows epicardial conduction and increases action potential duration in an optical mapping study of the isolated rabbit heart

    Science.gov (United States)

    Sung, Derrick; Mills, Robert W.; Schettler, Jan; Narayan, Sanjiv M.; Omens, Jeffrey H.; McCulloch, Andrew D.; McCullough, A. D. (Principal Investigator)

    2003-01-01

    INTRODUCTION: Mechanical stimulation can induce electrophysiologic changes in cardiac myocytes, but how mechanoelectric feedback in the intact heart affects action potential propagation remains unclear. METHODS AND RESULTS: Changes in action potential propagation and repolarization with increased left ventricular end-diastolic pressure from 0 to 30 mmHg were investigated using optical mapping in isolated perfused rabbit hearts. With respect to 0 mmHg, epicardial strain at 30 mmHg in the anterior left ventricle averaged 0.040 +/- 0.004 in the muscle fiber direction and 0.032 +/- 0.006 in the cross-fiber direction. An increase in ventricular loading increased average epicardial activation time by 25%+/- 3% (P action potential duration at 20% repolarization (APD20) but did at 80% repolarization (APD80), from 179 +/- 7 msec to 207 +/- 5 msec (P action potential duration by a load-dependent mechanism that may not involve stretch-activated channels.

  20. Increased amygdala reactivity following early life stress: a potential resilience enhancer role.

    Science.gov (United States)

    Yamamoto, Tetsuya; Toki, Shigeru; Siegle, Greg J; Takamura, Masahiro; Takaishi, Yoshiyuki; Yoshimura, Shinpei; Okada, Go; Matsumoto, Tomoya; Nakao, Takashi; Muranaka, Hiroyuki; Kaseda, Yumiko; Murakami, Tsuneji; Okamoto, Yasumasa; Yamawaki, Shigeto

    2017-01-18

    Amygdala hyper-reactivity is sometimes assumed to be a vulnerability factor that predates depression; however, in healthy people, who experience early life stress but do not become depressed, it may represent a resilience mechanism. We aimed to test these hypothesis examining whether increased amygdala activity in association with a history of early life stress (ELS) was negatively or positively associated with depressive symptoms and impact of negative life event stress in never-depressed adults. Twenty-four healthy participants completed an individually tailored negative mood induction task during functional magnetic resonance imaging (fMRI) assessment along with evaluation of ELS. Mood change and amygdala reactivity were increased in never-depressed participants who reported ELS compared to participants who reported no ELS. Yet, increased amygdala reactivity lowered effects of ELS on depressive symptoms and negative life events stress. Amygdala reactivity also had positive functional connectivity with the bilateral DLPFC, motor cortex and striatum in people with ELS during sad memory recall. Increased amygdala activity in those with ELS was associated with decreased symptoms and increased neural features, consistent with emotion regulation, suggesting that preservation of robust amygdala reactions may reflect a stress buffering or resilience enhancing factor against depression and negative stressful events.

  1. N-Terminal Plasmodium vivax Merozoite Surface Protein-1, a Potential Subunit for Malaria Vivax Vaccine

    Directory of Open Access Journals (Sweden)

    Fernanda G. Versiani

    2013-01-01

    Full Text Available The human malaria is widely distributed in the Middle East, Asia, the western Pacific, and Central and South America. Plasmodium vivax started to have the attention of many researchers since it is causing diseases to millions of people and several reports of severe malaria cases have been noticed in the last few years. The lack of in vitro cultures for P. vivax represents a major delay in developing a functional malaria vaccine. One of the major candidates to antimalarial vaccine is the merozoite surface protein-1 (MSP1, which is expressed abundantly on the merozoite surface and capable of activating the host protective immunity. Studies have shown that MSP-1 possesses highly immunogenic fragments, capable of generating immune response and protection in natural infection in endemic regions. This paper shows humoral immune response to different proteins of PvMSP1 and the statement of N-terminal to be added to the list of potential candidates for malaria vivax vaccine.

  2. Motor unit action potential conduction velocity estimated from surface electromyographic signals using image processing techniques.

    Science.gov (United States)

    Soares, Fabiano Araujo; Carvalho, João Luiz Azevedo; Miosso, Cristiano Jacques; de Andrade, Marcelino Monteiro; da Rocha, Adson Ferreira

    2015-09-17

    In surface electromyography (surface EMG, or S-EMG), conduction velocity (CV) refers to the velocity at which the motor unit action potentials (MUAPs) propagate along the muscle fibers, during contractions. The CV is related to the type and diameter of the muscle fibers, ion concentration, pH, and firing rate of the motor units (MUs). The CV can be used in the evaluation of contractile properties of MUs, and of muscle fatigue. The most popular methods for CV estimation are those based on maximum likelihood estimation (MLE). This work proposes an algorithm for estimating CV from S-EMG signals, using digital image processing techniques. The proposed approach is demonstrated and evaluated, using both simulated and experimentally-acquired multichannel S-EMG signals. We show that the proposed algorithm is as precise and accurate as the MLE method in typical conditions of noise and CV. The proposed method is not susceptible to errors associated with MUAP propagation direction or inadequate initialization parameters, which are common with the MLE algorithm. Image processing -based approaches may be useful in S-EMG analysis to extract different physiological parameters from multichannel S-EMG signals. Other new methods based on image processing could also be developed to help solving other tasks in EMG analysis, such as estimation of the CV for individual MUs, localization and tracking of innervation zones, and study of MU recruitment strategies.

  3. High-accuracy water potential energy surface for the calculation of infrared spectra

    Science.gov (United States)

    Mizus, Irina I.; Kyuberis, Aleksandra A.; Zobov, Nikolai F.; Makhnev, Vladimir Yu.; Polyansky, Oleg L.; Tennyson, Jonathan

    2018-03-01

    Transition intensities for small molecules such as water and CO2 can now be computed with such high accuracy that they are being used to systematically replace measurements in standard databases. These calculations use high-accuracy ab initio dipole moment surfaces and wave functions from spectroscopically determined potential energy surfaces (PESs). Here, an extra high-accuracy PES of the water molecule (H216O) is produced starting from an ab initio PES which is then refined to empirical rovibrational energy levels. Variational nuclear motion calculations using this PES reproduce the fitted energy levels with a standard deviation of 0.011 cm-1, approximately three times their stated uncertainty. The use of wave functions computed with this refined PES is found to improve the predicted transition intensities for selected (problematic) transitions. A new room temperature line list for H216O is presented. It is suggested that the associated set of line intensities is the most accurate available to date for this species. This article is part of the theme issue `Modern theoretical chemistry'.

  4. High-accuracy water potential energy surface for the calculation of infrared spectra.

    Science.gov (United States)

    Mizus, Irina I; Kyuberis, Aleksandra A; Zobov, Nikolai F; Makhnev, Vladimir Yu; Polyansky, Oleg L; Tennyson, Jonathan

    2018-03-13

    Transition intensities for small molecules such as water and CO 2 can now be computed with such high accuracy that they are being used to systematically replace measurements in standard databases. These calculations use high-accuracy ab initio dipole moment surfaces and wave functions from spectroscopically determined potential energy surfaces (PESs). Here, an extra high-accuracy PES of the water molecule (H 2 16 O) is produced starting from an ab initio PES which is then refined to empirical rovibrational energy levels. Variational nuclear motion calculations using this PES reproduce the fitted energy levels with a standard deviation of 0.011 cm -1 , approximately three times their stated uncertainty. The use of wave functions computed with this refined PES is found to improve the predicted transition intensities for selected (problematic) transitions. A new room temperature line list for H 2 16 O is presented. It is suggested that the associated set of line intensities is the most accurate available to date for this species.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Author(s).

  5. Calculation of electrical potentials on the surface of a realistic head model by finite differences

    International Nuclear Information System (INIS)

    Lemieux, L.; McBride, A.; Hand, J.W.

    1996-01-01

    We present a method for the calculation of electrical potentials at the surface of realistic head models from a point dipole generator based on a 3D finite-difference algorithm. The model was validated by comparing calculated values with those obtained algebraically for a three-shell spherical model. For a 1.25 mm cubic grid size, the mean error was 4.9% for a superficial dipole (3.75 mm from the inner surface of the skull) pointing in the radial direction. The effect of generator discretization and node spacing on the accuracy of the model was studied. Three values of the node spacing were considered: 1, 1.25 and 1.5 mm. The mean relative errors were 4.2, 6.3 and 9.3%, respectively. The quality of the approximation of a point dipole by an array of nodes in a spherical neighbourhood did not depend significantly on the number of nodes used. The application of the method to a conduction model derived from MRI data is demonstrated. (author)

  6. Neospora caninum surface antigen (p40) is a potential diagnostic marker for cattle neosporosis.

    Science.gov (United States)

    He, Pengfei; Li, Jianhua; Gong, Pengtao; Liu, Chengwu; Zhang, Guocai; Yang, Ju; Tuo, Wenbin; Yang, Bintong; Zhang, Xichen

    2013-05-01

    Neospora caninum is an intracellular protozoan that infects domestic and wild canids as well as many warm-blooded animals as shown by the isolation of viable parasites. The effectiveness of diagnostic tests for detecting specific antibodies against N. caninum is hampered by potential cross-reaction with other Coccidia. So, there is currently an urgent need for a sensitive and specific diagnostic assay for detecting N. caninum in animals. The N. caninum 40-kD surface antigen (p40), similar to NcSAG1 and NcSRS2, was shown to belong to surface antigen super family and thus represents an excellent marker for the diagnosis of neosporosis. In order to test the hypothesis, recombinant Ncp40 (rNcp40) was expressed in Escherichia coli, and an indirect ELISA test was developed using recombinant NCp40 antigen for N. caninum serodiagnosis. The antigen used in this study did not have cross-reactivity with anti-Toxoplasma gondii serum. Anti-p40 antibodies were detected by ELISA in the sera of Yellow cattle and were compared with (IFAT). Optimal sensitivity and specificity (98.2 and 98.6 %) were identified by IFAT. Additionally, 37 positive sera of T. gondii were detected and there was no significant difference with the negative serum of N. caninum. The rNcp40 ELISA developed here provides a specific and sensitive assay for detecting neosporosis in cattle.

  7. Causes for the recent increase in sea surface salinity in the north ...

    African Journals Online (AJOL)

    ... salinity budget was used to identify the mechanisms responsible for the increase. When comparing the period 2002–2009 with the period 1993–2001, significant changes in the salt budget were identified. The increase in SSS in the more recent period appeared to be driven by changes in the atmospheric freshwater flux, ...

  8. Ocean acidification increases cadmium accumulation in marine bivalves: a potential threat to seafood safety.

    Science.gov (United States)

    Shi, Wei; Zhao, Xinguo; Han, Yu; Che, Zhumei; Chai, Xueliang; Liu, Guangxu

    2016-01-21

    To date, the effects of ocean acidification on toxic metals accumulation and the underlying molecular mechanism remains unknown in marine bivalve species. In the present study, the effects of the realistic future ocean pCO2 levels on the cadmium (Cd) accumulation in the gills, mantle and adductor muscles of three bivalve species, Mytilus edulis, Tegillarca granosa, and Meretrix meretrix, were investigated. The results obtained suggested that all species tested accumulated significantly higher Cd (p ocean acidification-induced increase in Cd accumulation may have occurred due to (i) the ocean acidification increased the concentration of Cd and the Cd(2+)/Ca(2+) in the seawater, which in turn increased the Cd influx through Ca channel; (ii) the acidified seawater may have brought about epithelia damage, resulting in easier Cd penetration; and (iii) ocean acidification hampered Cd exclusion.

  9. Osteogenic potential of bone marrow stromal cells on smooth, roughened, and tricalcium phosphate-modified titanium alloy surfaces.

    LENUS (Irish Health Repository)

    Colombo, John S

    2012-09-01

    This study investigated the influence of smooth, roughened, and tricalcium phosphate (TCP)-coated roughened titanium-aluminum-vanadium (Ti-6Al-4V) surfaces on the osteogenic potential of rat bone marrow stromal cells (BMSCs).

  10. Surface potential measurement of insulators in negative-ion implantation by secondary electron energy-peak shift

    International Nuclear Information System (INIS)

    Nagumo, Shoji; Toyota, Yoshitaka; Tsuji, Hiroshi; Gotoh, Yasuhito; Ishikawa, Junzo; Sakai, Shigeki; Tanjyo, Masayasu; Matsuda, Kohji.

    1993-01-01

    Negative-ion implantation is expected to realize charge-up free implantation. In this article, about a way to specify surface potential of negative-ion implanted insulator by secondary-electron-energy distribution, its principle and preliminary experimental results are described. By a measuring system with retarding field type energy analyzer, energy distribution of secondary electron from insulator of Fused Quartz in negative-carbon-ion implantation was measured. As a result the peak-shift of its energy distribution resulted according with the surface potential of insulator. It was found that surface potential of insulator is negatively charged by only several volts. Thus, negative-ion implanted insulator reduced its surface charge-up potential (without any electron supply). Therefore negative-ion implantation is considered to be much more effective method than conventional positive-ion implantation. (author)

  11. Event-related potentials reveal increased distraction by salient global objects in older adults

    DEFF Research Database (Denmark)

    Wiegand, Iris; Finke, Kathrin; Töllner, Thomas

    Age-related changes in visual functions influence how older individuals perceive and react upon objects in their environment. In particular, older individuals might be more distracted by highly salient, irrelevant information. Kanizsa figures induce a ‘global precedence’ effect, which reflects...... a processing advantage for salient whole-object representations relative to configurations of local elements not inducing a global form. We investigated event-related potential (ERP) correlates of age-related decline in visual abilities, and specifically, distractibility by salient global objects in visual...

  12. Increased transient receptor potential vanilloid type 1 (TRPV1) channel expression in hypertrophic heart

    DEFF Research Database (Denmark)

    Thilo, Florian; Liu, Ying; Schulz, Nico

    2010-01-01

    The aim of this study was to compare the expression of transient receptor potential vanilloid type 1 (TRPV1) channels in hypertrophic hearts from transgenic mice showing overexpression of the catalytic subunit alpha of protein phosphatase 2A alpha (PP2Ac alpha) with wild-type mice and with TRPV1-...... alpha transgenic mice compared to wild-type mice and TRPV1-/- mice (8.6±1.3mg/g; 5.4±0.3mg/g; and 5.4±0.4mg/g; respectively; p...

  13. Dysfunctional immunometabolic effects of vitamin D deficiency, increased cardiometabolic risk. Potential epidemiological alert in America?

    Science.gov (United States)

    Rosas-Peralta, Martin; Holick, Michael F; Borrayo-Sánchez, Gabriela; Madrid-Miller, Alejandra; Ramírez-Árias, Erick; Arizmendi-Uribe, Efrain

    2017-03-01

    Vitamin D deficiency is a serious public health problem worldwide that affects not only skeletal health, but also a wide range of acute and chronic diseases. However, there is still skepticism because of the lack of randomized, controlled trials to support association studies on the benefits of vitamin D for non-skeletal health. This review was based on articles published during the 1980-2015 obtained from the Cochrane Central Register of controlled trials, MEDLINE and PubMed, and focuses on recent challenges with regard to the definition of vitamin D deficiency and how to achieve optimal serum 25-hydroxyvitamin D levels from dietary sources, supplements, and sun exposure. The effect of vitamin D on epigenetic fetal programming and regulation of genes that may potentially explain why vitamin D could have such lifelong comprehensive health benefits is reviewed. Optimization of vitamin D levels in children and adults around the world has potential benefits to improve skeletal health and to reduce the risk of chronic diseases, including some types of cancer, autoimmune diseases, infectious diseases, type 2 diabetes mellitus, and severe cardiovascular disorders such as atherothrombosis, neurocognitive disorders, and mortality. Copyright © 2017 SEEN. Publicado por Elsevier España, S.L.U. All rights reserved.

  14. WASmith The genetic potential of dairy cows has increased to such

    African Journals Online (AJOL)

    probably offer the best opportunity of supplementing fat in dairy diets. It also seems improbable that the gossypol content of whole cottonseed can have detrimental effects if fed at moderate levels and in well-balanced diets. The heat treatment of oilseeds (cottonseed and soybeans) increased milk production in most studies ...

  15. The potential of legislation on organ donation to increase the supply of donor organs

    NARCIS (Netherlands)

    Coppen, Remco; Friele, Roland D.; van der Zee, Jouke; Gevers, Sjef K.

    2010-01-01

    The aim of this paper is to assess the possibilities to adapt the 1998 Dutch Organ Donation Act, taking account of fundamental principles such as the right to physical integrity, equitable access to and equal availability of care, and the non-commerciality principle, with a view to increasing the

  16. Potential for increased use of cereal grain forages on dairy operations

    Science.gov (United States)

    Farmers are increasingly using cereal grain cover crops, which allows them to take advantage of additional growing days in early spring and late fall. The use of cereal grain forages, such as rye, wheat, or triticale as cover crops helps to reduce soil and nutrient losses, and also allows for addit...

  17. Acces to railway stations and its potential in increasing rail use

    NARCIS (Netherlands)

    Brons, M.R.E.; Givoni, M.; Rietveld, P.

    2008-01-01

    The propensity to travel by rail, and not, for example by car, can be considered to be a factor of the rail service offered, the access to it and the characteristics of the population served. Efforts to increase rail use usually focus on the rail service itself while the accessibility of the rail

  18. Analyzing the Potential for Unmanned Aerial Systems (UAS) Photogrammetry in Estimating Surface Deformations at a Geothermal Fiel

    Science.gov (United States)

    Pai, H.; Burnett, J.; Sladek, C.; Wing, M.; Feigl, K. L.; Selker, J. S.; Tyler, S.; Team, P.

    2016-12-01

    UAS systems equipped with a variety of spectral imaging devices are increasingly incorporated in spatial environmental assessments of continental surfaces (e.g., digital elevation maps, vegetative coverage classifications, surface temperatures). This presented work performed by the UAS team at the Center for Transformative Environmental Monitoring Programs (AirCTEMPS) examines the potential to measure small (sub-cm) deformation from a geothermal injection experiment at Brady's geothermal field in western Nevada (USA). Areal mapping of the 700 x 270 m area of interest was conducted with a nadir pointing Sony A5100 digital camera onboard an autopiloted quadcopter. A total of 16 ground control points were installed using a TopCon GR3 GPS receiver. Two such mapping campaigns were conducted with one before and one after an anticipated surface deformation event. A digital elevation map (DEM) for each time period was created from over 1500 images having 80% overlap/sidelap by using structure from motion (SfM) via Agisoft Photoscan software. The resulting DEM resolution was 8 mm/pixel with residual aerial triangulation errors was < 5 mm. We present preliminary results from an optimized workflow which achieved errors and average differential DEM heights between campaigns at the cm-scale which is broader than the maximum expected deformation. Despite the disconnect between error and deformation severity, this study presents a unique application of sub-cm UAS-based DEMs and further distinguishes itself by comparing results to concurrent Interferometric Synthetic Radar (InSAR). The intent of our study and presentation of results is to streamline, cross-validate, and share methods to encourage further adoption of UAS imagery into the standard toolkit for environmental surface sensing across spatial scales.

  19. Accurate high level ab initio-based global potential energy surface and dynamics calculations for ground state of CH2(+).

    Science.gov (United States)

    Li, Y Q; Zhang, P Y; Han, K L

    2015-03-28

    A global many-body expansion potential energy surface is reported for the electronic ground state of CH2 (+) by fitting high level ab initio energies calculated at the multireference configuration interaction level with the aug-cc-pV6Z basis set. The topographical features of the new global potential energy surface are examined in detail and found to be in good agreement with those calculated directly from the raw ab initio energies, as well as previous calculations available in the literature. In turn, in order to validate the potential energy surface, a test theoretical study of the reaction CH(+)(X(1)Σ(+))+H((2)S)→C(+)((2)P)+H2(X(1)Σg (+)) has been carried out with the method of time dependent wavepacket on the title potential energy surface. The total integral cross sections and the rate coefficients have been calculated; the results determined that the new potential energy surface can both be recommended for dynamics studies of any type and as building blocks for constructing the potential energy surfaces of larger C(+)/H containing systems.

  20. Modified colloidal primitive model as a homogeneous surface charge distribution: ζ-potential.

    Science.gov (United States)

    Manzanilla-Granados, Héctor M; Lozada-Cassou, Marcelo

    2013-10-03

    An integral equations theory is derived and applied to a modified colloidal primitive model (MCPM), for finite concentration colloidal dispersions. In MCPM, the charge on the colloidal particle is assumed to be smeared on its surface. We find important quantitative and qualitative differences of the ζ-potential, induced charge, and the colloid-colloid electric effective force, calculated in the MCPM, with those obtained from the colloidal primitive model (CPM), where the colloidal charge is assumed to be in the center of the particle, in spite of the fact that, due to Gauss's law, both models have the same particle distribution function. In particular, for the same parameters, while the ζ-potential is positive in MCPM, is negative in the CPM, implying opposite electrophoretic mobilities, μ. An inverse μ has been theoretically predicted in the past, for infinite dilution colloidal dispersions. The MCPM could be a better model for some colloidal particles. In both models, the CPM and the MCPM, it is found a very long-range colloid-colloid correlation, in accordance with previous Monte Carlo simulations. The electrostatic, as well as entropic, like-charged colloid-colloid forces are oscillatory, implying a long-range attraction.

  1. Protein hydrolysate from turkey meat and optimization of its antioxidant potential by response surface methodology.

    Science.gov (United States)

    Wang, Daoying; Shahidi, Fereidoon

    2018-05-01

    The objective of this research was to optimize antioxidant potential of hydrolyzed protein using Flavourzyme assisted hydrolysis of turkey meat and compare the antioxidant activity of hydrolysates from turkey meat, chicken, and beef. Response surface methodology (RSM) was used to determine the optimal Flavourzyme hydrolysis conditions for preparation of hydrolysate from turkey meat, which were at a temperature of 50.09°C, pH of 5.42, and processing time of 1.08 hours. For comparison, antioxidant activities of the hydrolysate from turkey meat, chicken, and beef under the optimum conditions were determined using reducing power, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation, hydroxyl radical, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities. The antioxidant activity of turkey meat and chicken meat was significantly higher than that of beef (P turkey meat, indicating the potential use of it as a functional food ingredient with shelf-life extension purposes.

  2. Recent strategies of increasing metal tolerance and phytoremediation potential using genetic transformation of plants.

    Science.gov (United States)

    Koźmińska, Aleksandra; Wiszniewska, Alina; Hanus-Fajerska, Ewa; Muszyńska, Ewa

    2018-01-01

    Avoidance and reduction of soil contamination with heavy metals is one of the most serious global challenges. Nowadays, science offers us new opportunities of utilizing plants to extract toxic elements from the soil by means of phytoremediation. Plant abilities to uptake, translocate, and transform heavy metals, as well as to limit their toxicity, may be significantly enhanced via genetic engineering. This paper provides a comprehensive review of recent strategies aimed at the improvement of plant phytoremediation potential using plant transformation and employing current achievements in nuclear and cytoplasmic genome transformation. Strategies for obtaining plants suitable for effective soil clean-up and tolerant to excessive concentrations of heavy metals are critically assessed. Promising directions in genetic manipulations, such as gene silencing and cis - and intragenesis, are also discussed. Moreover, the ways of overcoming disadvantages of phytoremediation using genetic transformation approachare proposed. The knowledge gathered here could be useful for designing new research aimed at biotechnological improvement of phytoremediation efficiency.

  3. Increased threshold of short-latency motor evoked potentials in transgenic mice expressing Channelrhodopsin-2.

    Science.gov (United States)

    Wu, Wei; Xiong, Wenhui; Zhang, Ping; Chen, Lifang; Fang, Jianqiao; Shields, Christopher; Xu, Xiao-Ming; Jin, Xiaoming

    2017-01-01

    Transgenic mice that express channelrhodopsin-2 or its variants provide a powerful tool for optogenetic study of the nervous system. Previous studies have established that introducing such exogenous genes usually does not alter anatomical, electrophysiological, and behavioral properties of neurons in these mice. However, in a line of Thy1-ChR2-YFP transgenic mice (line 9, Jackson lab), we found that short-latency motor evoked potentials (MEPs) induced by transcranial magnetic stimulation had a longer latency and much lower amplitude than that of wild type mice. MEPs evoked by transcranial electrical stimulation also had a much higher threshold in ChR2 mice, although similar amplitudes could be evoked in both wild and ChR2 mice at maximal stimulation. In contrast, long-latency MEPs evoked by electrically stimulating the motor cortex were similar in amplitude and latency between wild type and ChR2 mice. Whole-cell patch clamp recordings from layer V pyramidal neurons of the motor cortex in ChR2 mice revealed no significant differences in intrinsic membrane properties and action potential firing in response to current injection. These data suggest that corticospinal tract is not accountable for the observed abnormality. Motor behavioral assessments including BMS score, rotarod, and grid-walking test showed no significant differences between the two groups. Because short-latency MEPs are known to involve brainstem reticulospinal tract, while long-latency MEPs mainly involve primary motor cortex and dorsal corticospinal tract, we conclude that this line of ChR2 transgenic mice has normal function of motor cortex and dorsal corticospinal tract, but reduced excitability and responsiveness of reticulospinal tracts. This abnormality needs to be taken into account when using these mice for related optogenetic study.

  4. Increased chromatin plasticity supports enhanced metastatic potential of mouse melanoma cells.

    Science.gov (United States)

    Maizels, Yael; Elbaz, Adi; Hernandez-Vicens, Rosari; Sandrusy, Oshrat; Rosenberg, Anna; Gerlitz, Gabi

    2017-08-15

    Metastasis formation is strongly dependent on the migration capabilities of tumor cells. Recently it has become apparent that nuclear structure and morphology affect the cellular ability to migrate. Previously we found that migration of melanoma cells is both associated with and dependent on global chromatin condensation. Therefore, we anticipated that tumor progression would be associated with increased chromatin condensation. Interestingly, the opposite has been reported for melanoma. In trying to resolve this contradiction, we show that during growth conditions, tumor progression is associated with global chromatin de-condensation that is beneficial for faster proliferation. However, upon induction of migration, in both low- and high-metastatic mouse melanoma cells chromatin undergoes condensation to support cell migration. Our results reveal that throughout tumor progression induction of chromatin condensation by migration signals is maintained, whereas the organization of chromatin during growth conditions is altered. Thus, tumor progression is associated with an increase in chromatin dynamics. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Potential benefits of the increase in nuclear cooperation between Latin and North American countries

    International Nuclear Information System (INIS)

    Vieira, Wilson J.; Soto-Urbina, Ligia M.; Cabral, Arnoldo S.

    1997-01-01

    Economic problems of Latin American countries are increasing the pressure on the world's environmental health. Therefore, it is necessary to create efficient means to support fast and environmentally safe development efforts in the region. The objective of this work is to stress the importance of nuclear technology cooperation between American countries as an important means to foster economic and social growth. Scientific production in Brazil and other Latin American countries has not increased significantly in the last decades, and modern technology is only available to a small fraction of the population. To ameliorate this problem it is necessary to improve technological cooperation throughout the american continent, which will be facilitated by the existing scientific capacity available in some Latin American universities and laboratories. Small and big countries alike need to establish their share in the cooperative effort to reduce present day technology hazards. (author)

  6. Increasing surface albedo in the dry subtropical forests of South America: the role of agriculture expansion and management

    Science.gov (United States)

    Houspanossian, J.; Kuppel, S.; Gimenez, R.; Jobbagy, E. G.; Nosetto, M. D.

    2014-12-01

    The increase in surface albedo inherent to land clearing and cultivation (land-cover change, LCC) in the subtropical dry forests of the South American Chaco offsets part of the radiative forcing (RF) of the related carbon emissions. The magnitude of these albedo changes, however, is also dependent on shifts in agricultural practices (land-management change, LMC) and will influence the net effect on Earth's radiation balance as well as other potential feedbacks on climate. We quantified the surface albedo changes between 2001 and 2013 and the consequent shifts in the radiation balance resulting from LCC and LMC, using MODIS imagery a columnar radiation model parameterized with satellite data. Agricultural systems replacing dry forests presented a large variety of managements, ranging from pasture systems with remnant trees to different grain crops, displaying a wide range of phenologies. Cultivated lands showed higher and more variable albedo values (mean = 0.162, Standard Deviation = 0.013, n = 10,000 pixels) than the dry forests they replace (mean = 0.113, SD = 0.010, n = 10,000). These albedo contrasts resulted in a cooling RF of deforestation of -10.1 W m-2 on average, but both livestock and grain crop production systems showed large differences among the different land management options. For instance, livestock systems based on open pasture lands showed higher albedo change and RF (0.06 and -16.3 W m-2, respectively) than silvopastoral systems (0.02 and -4.4 W m-2). Similarly in cropping systems, the replacement of double-cropping by single summer crops, a widespread process in the region lately, resulted in higher albedo change (0.06 vs. 0.08) and RF (-16.3 vs. -22.3 W m-2). Although the effects of LCC on climate are widely acknowledged, those of LMC are still scarcely understood. In the Chaco region, the latter could play an important role and offer a yet-overlooked pathway to influence the radiative balance of our planet.

  7. Contributions of solar-wind induced potential sputtering to the lunar surface erosion rate and it's exosphere

    Science.gov (United States)

    Alnussirat, S. T.; Barghouty, A. F.; Edmunson, J. E.; Sabra, M. S.; Rickman, D. L.

    2018-04-01

    Sputtering of lunar regolith by solar-wind protons and heavy ions with kinetic energies of about 1 keV/amu is an important erosive process that affects the lunar surface and exosphere. It plays an important role in changing the chemical composition and thickness of the surface layer, and in introducing material into the exosphere. Kinetic sputtering is well modeled and understood, but understanding of mechanisms of potential sputtering has lagged behind. In this study we differentiate the contributions of potential sputtering from the standard (kinetic) sputtering in changing the chemical composition and erosion rate of the lunar surface. Also we study the contribution of potential sputtering in developing the lunar exosphere. Our results show that potential sputtering enhances the total characteristic sputtering erosion rate by about 44%, and reduces sputtering time scales by the same amount. Potential sputtering also introduces more material into the lunar exosphere.

  8. Winter sowing of adapted lines as a potential yield increase strategy in lentil (Lens culinaris Medik.)

    Energy Technology Data Exchange (ETDEWEB)

    Barrios, A.; Aparicio, T.; Rodríguez, M.J.; Pérez de la Vega, M.; Caminero, C.

    2016-11-01

    Lentil (Lens culinaris Medik. subsp. culinaris) is a traditional crop in Spain although current grain yield in Spain is relatively low and unstable. The effect of an early sowing date (winter sowing) on yield in the Spanish Central Plateau (meseta) was analyzed comparing it to the traditional spring sowing. Yield from eleven cultivars currently available for sowing in Spain and two F6:7 populations of recombinant inbred lines (RIL), ´Precoz´ × ´WA8649041´ (89 lines) and ´BGE016365´ × ´ILL1918´ (118 lines), was evaluated in winter and spring sowing dates for three seasons (2005/06, 2006/07 and 2007/08) and two localities. Yield and stability were assessed by the method of consistency of performance with some modifications. When comparing with the best currently available cultivars sown in the traditional spring sowing date, (with an estimated average yield of 43.9 g/m in our experimental conditions), winter sowing using adapted breeding lines proved to be a suitable strategy for increasing lentil yield and yield stability in the Spanish meseta, with an average yield increase of 111% (reaching an estimated yield of 92.8 g/m). Results point to that lentil production can greatly increase in the Spanish meseta if adequate plant materials, such as some of the lines analyzed, are sown at late fall. (Author)

  9. Cascading pulse tubes on a large diaphragm pressure wave generator to increase liquefaction potential

    Science.gov (United States)

    Caughley, A.; Meier, J.; Nation, M.; Reynolds, H.; Boyle, C.; Tanchon, J.

    2017-12-01

    Fabrum Solutions, in collaboration with Absolut System and Callaghan Innovation, produce a range of large pulse tube cryocoolers based on metal diaphragm pressure wave generator technology (DPWG). The largest cryocooler consists of three in-line pulse tubes working in parallel on a 1000 cm3 swept volume DPWG. It has demonstrated 1280 W of refrigeration at 77 K, from 24 kW of input power and was subsequently incorporated into a liquefaction plant to produce liquid nitrogen for an industrial customer. The pulse tubes on the large cryocooler each produced 426 W of refrigeration at 77 K. However, pulse tubes can produce more refrigeration with higher efficiency at higher temperatures. This paper presents the results from experiments to increase overall liquefaction throughput by operating one or more pulse tubes at a higher temperature to pre-cool the incoming gas. The experiments showed that the effective cooling increased to 1500 W resulting in an increase in liquefaction rate from 13 to 16 l/hour.

  10. Symbiosis with an endobacterium increases the fitness of a mycorrhizal fungus, raising its bioenergetic potential.

    Science.gov (United States)

    Salvioli, Alessandra; Ghignone, Stefano; Novero, Mara; Navazio, Lorella; Venice, Francesco; Bagnaresi, Paolo; Bonfante, Paola

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) occur in the rhizosphere and in plant tissues as obligate symbionts, having key roles in plant evolution and nutrition. AMF possess endobacteria, and genome sequencing of the endobacterium Candidatus Glomeribacter gigasporarum revealed a reduced genome and a dependence on the fungal host. To understand the effect of bacteria on fungal fitness, we used next-generation sequencing to analyse the transcriptional profile of Gigaspora margarita in the presence and in the absence of its endobacterium. Genomic data on AMF are limited; therefore, we first generated a gene catalogue for G. margarita. Transcriptome analysis revealed that the endobacterium has a stronger effect on the pre-symbiotic phase of the fungus. Coupling transcriptomics with cell biology and physiological approaches, we demonstrate that the bacterium increases the fungal sporulation success, raises the fungal bioenergetic capacity, increasing ATP production, and eliciting mechanisms to detoxify reactive oxygen species. By using TAT peptide to translocate the bioluminescent calcium reporter aequorin, we demonstrated that the line with endobacteria had a lower basal intracellular calcium concentration than the cured line. Lastly, the bacteria seem to enhance the fungal responsiveness to strigolactones, the plant molecules that AMF perceive as branching factors. Although the endobacterium exacts a nutritional cost on the AMF, endobacterial symbiosis improves the fungal ecological fitness by priming mitochondrial metabolic pathways and giving the AMF more tools to face environmental stresses. Thus, we hypothesise that, as described for the human microbiota, endobacteria may increase AMF innate immunity.

  11. Is it really possible to increase J{sub c} by reducing the pinning potential?

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Roy; Sawh, Ravi-Persad; Gandini, Alberto; Mayes, Bill; Parks, Drew [Beam Particle Dynamics Laboratories, Department of Physics, and Texas Center for Superconductivity at UH, University of Houston, Houston, TX 77204-5005 (United States)

    2007-09-15

    We discuss an experiment on large-grain YBCO, the intent of which is to compare the effectiveness of continuous columnar pinning centres (CCPC) to that of discontinuous aligned pinning centres, in their ability to increase J{sub c}. We find that discontinuous pinning is far superior. The motivation and design of the experiment are reviewed. High-energy heavy ions were utilized to produce pinning damage of controlled morphology. The resulting increase in J{sub c} is presented as a function of the variable S{sub e}, which is closely related to the discontinuity and diameter of the damage. The dependence of J{sub c} on magnetic field, temperature, and F{sub i} (the number of ion tracks per cm{sup 2}) is presented and discussed. The dependence of H{sub irr} on S{sub e} and F{sub i}, and the temperature and fluence dependence of a J{sub c} fishtail effect, are presented. The experimental results indicate that multiple-in-line-damage (MILD), despite its discontinuities, is far more effective in increasing J{sub c} than CCPCs are.

  12. Low-energy structures of benzene clusters with a novel accurate potential surface.

    Science.gov (United States)

    Bartolomei, M; Pirani, F; Marques, J M C

    2015-12-05

    The benzene-benzene (Bz-Bz) interaction is present in several chemical systems and it is known to be crucial in understanding the specificity of important biological phenomena. In this work, we propose a novel Bz-Bz analytical potential energy surface which is fine-tuned on accurate ab initio calculations in order to improve its reliability. Once the Bz-Bz interaction is modeled, an analytical function for the energy of the Bzn clusters may be obtained by summing up over all pair potentials. We apply an evolutionary algorithm (EA) to discover the lowest-energy structures of Bzn clusters (for n=2-25), and the results are compared with previous global optimization studies where different potential functions were employed. Besides the global minimum, the EA also gives the structures of other low-lying isomers ranked by the corresponding energy. Additional ab initio calculations are carried out for the low-lying isomers of Bz3 and Bz4 clusters, and the global minimum is confirmed as the most stable structure for both sizes. Finally, a detailed analysis of the low-energy isomers of the n = 13 and 19 magic-number clusters is performed. The two lowest-energy Bz13 isomers show S6 and C3 symmetry, respectively, which is compatible with the experimental results available in the literature. The Bz19 structures reported here are all non-symmetric, showing two central Bz molecules surrounded by 12 nearest-neighbor monomers in the case of the five lowest-energy structures. © 2015 Wiley Periodicals, Inc.

  13. THE EFFECTS OF CRACKING ON THE SURFACE POTENTIAL OF ICY GRAINS IN SATURN’S E-RING: LABORATORY STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Caixia; Bahr, David A.; Dukes, Catherine A.; Baragiola, Raúl A., E-mail: cb8nw@virginia.edu [Laboratory for Astrophysics and Surface Physics, Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904 (United States)

    2016-07-10

    Within Saturn's E-ring, dust grains are coated by water vapor co-released with ice grains from the geyser-like eruptions of Enceladus. These ice-coated grains have intrinsic surface potential and interact synergistically with the ions and electrons of Saturn's magnetospheric plasmas. We perform laboratory experiments to investigate the effects of water-ice growth on the surface potential, using amorphous solid water (ASW) films. We estimate the growth of the surface potential to be ∼ 2.5 mV (Earth) yr{sup 1} and 112 mV yr{sup 1} for E-ring grains at ∼4.5 R {sub s} and 3.95 R {sub s} outside Enceladus’s plume, respectively. In addition, our measurements show that the linear relationship between the surface potential and the film thickness, as described in previous studies, has an upper limit, where the film spontaneously cracks above a porosity-dependent critical thickness. Heating of the cracked films with (and without) deposited charge shows that significant positive (and negative) surface potentials are retained at temperatures above 110 K, contrary to the minimal values (roughly zero) for thin, transparent ASW films. The significant surface potentials observed on micron-scale cracked ice films after thermal cycling, (5–20) V, are consistent with Cassini measurements, which indicate a negative charge of up to 5 V for E-ring dust particles at ∼5 R {sub s}. Therefore, the native grain surface potential resulting from water-vapor coating must be included in modeling studies of interactions between E-ring icy surfaces and Saturn's magnetospheric plasma.

  14. Evaluation of potential surface rupture and review of current seismic hazards program at the Los Alamos National Laboratory. Final report

    International Nuclear Information System (INIS)

    1991-01-01

    This report summarizes the authors review and evaluation of the existing seismic hazards program at Los Alamos National Laboratory (LANL). The report recommends that the original program be augmented with a probabilistic analysis of seismic hazards involving assignment of weighted probabilities of occurrence to all potential sources. This approach yields a more realistic evaluation of the likelihood of large earthquake occurrence particularly in regions where seismic sources may have recurrent intervals of several thousand years or more. The report reviews the locations and geomorphic expressions of identified fault lines along with the known displacements of these faults and last know occurrence of seismic activity. Faults are mapped and categorized into by their potential for actual movement. Based on geologic site characterization, recommendations are made for increased seismic monitoring; age-dating studies of faults and geomorphic features; increased use of remote sensing and aerial photography for surface mapping of faults; the development of a landslide susceptibility map; and to develop seismic design standards for all existing and proposed facilities at LANL

  15. Increasing Dietary Phosphorus Intake from Food Additives: Potential for Negative Impact on Bone Health123

    Science.gov (United States)

    Takeda, Eiji; Yamamoto, Hironori; Yamanaka-Okumura, Hisami; Taketani, Yutaka

    2014-01-01

    It is important to consider whether habitual high phosphorus intake adversely affects bone health, because phosphorus intake has been increasing, whereas calcium intake has been decreasing in dietary patterns. A higher total habitual dietary phosphorus intake has been associated with higher serum parathyroid hormone (PTH) and lower serum calcium concentrations in healthy individuals. Higher serum PTH concentrations have been shown in those who consume foods with phosphorus additives. These findings suggest that long-term dietary phosphorus loads and long-term hyperphosphatemia may have important negative effects on bone health. In contrast, PTH concentrations did not increase as a result of high dietary phosphorus intake when phosphorus was provided with adequate amounts of calcium. Intake of foods with a ratio of calcium to phosphorus close to that found in dairy products led to positive effects on bone health. Several randomized controlled trials have shown positive relations between dairy intake and bone mineral density. In our loading test with a low-calcium, high-phosphorus lunch provided to healthy young men, serum PTH concentrations showed peaks at 1 and 6 h, and serum fibroblast growth factor 23 (FGF23) concentrations increased significantly at 8 h after the meal. In contrast, the high-calcium, high-phosphorus meal suppressed the second PTH and FGF23 elevations until 8 h after the meal. This implies that adequate dietary calcium intake is needed to overcome the interfering effects of high phosphorus intake on PTH and FGF23 secretion. FGF23 acts on the parathyroid gland to decrease PTH mRNA and PTH secretion in rats with normal kidney function. However, increased serum FGF23 is an early alteration of mineral metabolism in chronic kidney disease, causing secondary hyperthyroidism, and implying resistance of the parathyroid gland to the action of FGF23 in chronic kidney disease. These findings suggest that long-term high-phosphorus diets may impair bone health

  16. Increasing dietary phosphorus intake from food additives: potential for negative impact on bone health.

    Science.gov (United States)

    Takeda, Eiji; Yamamoto, Hironori; Yamanaka-Okumura, Hisami; Taketani, Yutaka

    2014-01-01

    It is important to consider whether habitual high phosphorus intake adversely affects bone health, because phosphorus intake has been increasing, whereas calcium intake has been decreasing in dietary patterns. A higher total habitual dietary phosphorus intake has been associated with higher serum parathyroid hormone (PTH) and lower serum calcium concentrations in healthy individuals. Higher serum PTH concentrations have been shown in those who consume foods with phosphorus additives. These findings suggest that long-term dietary phosphorus loads and long-term hyperphosphatemia may have important negative effects on bone health. In contrast, PTH concentrations did not increase as a result of high dietary phosphorus intake when phosphorus was provided with adequate amounts of calcium. Intake of foods with a ratio of calcium to phosphorus close to that found in dairy products led to positive effects on bone health. Several randomized controlled trials have shown positive relations between dairy intake and bone mineral density. In our loading test with a low-calcium, high-phosphorus lunch provided to healthy young men, serum PTH concentrations showed peaks at 1 and 6 h, and serum fibroblast growth factor 23 (FGF23) concentrations increased significantly at 8 h after the meal. In contrast, the high-calcium, high-phosphorus meal suppressed the second PTH and FGF23 elevations until 8 h after the meal. This implies that adequate dietary calcium intake is needed to overcome the interfering effects of high phosphorus intake on PTH and FGF23 secretion. FGF23 acts on the parathyroid gland to decrease PTH mRNA and PTH secretion in rats with normal kidney function. However, increased serum FGF23 is an early alteration of mineral metabolism in chronic kidney disease, causing secondary hyperthyroidism, and implying resistance of the parathyroid gland to the action of FGF23 in chronic kidney disease. These findings suggest that long-term high-phosphorus diets may impair bone health

  17. D2 dissociative adsorption on and associative desorption from Si(100): Dynamic consequences of an ab initio potential energy surface

    DEFF Research Database (Denmark)

    Luntz, A. C.; Kratzer, Peter

    1996-01-01

    favors the symmetric one. Under the conditions of many experiments, either could dominate. The calculations show quite weak dynamic coupling to the Si lattice for both paths, i.e., weak surface temperature dependences to dissociation and small energy loss to the lattice upon desorption......Dynamical calculations are reported for D-2 dissociative chemisorption on and associative desorption from a Si(100) surface. These calculations use the dynamically relevant effective potential which is based on an ab initio potential energy surface for the ''pre-paired'' species. Three coordinates...

  18. Adaptation policies to increase terrestrial ecosystem resilience. Potential utility of a multicriteria approach

    Energy Technology Data Exchange (ETDEWEB)

    de Bremond, Ariane [Univ. of Maryland, College Park, MD (United States); Joint Global Change Research Inst., College Park, MD (United States); Engle, Nathan L. [World Bank, Washington, DC (United States)

    2014-01-30

    Climate change is rapidly undermining terrestrial ecosystem resilience and capacity to continue providing their services to the benefit of humanity and nature. Because of the importance of terrestrial ecosystems to human well-being and supporting services, decision makers throughout the world are busy creating policy responses that secure multiple development and conservation objectives- including that of supporting terrestrial ecosystem resilience in the context of climate change. This article aims to advance analyses on climate policy evaluation and planning in the area of terrestrial ecosystem resilience by discussing adaptation policy options within the ecology-economy-social nexus. The paper evaluates these decisions in the realm of terrestrial ecosystem resilience and evaluates the utility of a set of criteria, indicators, and assessment methods, proposed by a new conceptual multi-criteria framework for pro-development climate policy and planning developed by the United Nations Environment Programme. Potential applications of a multicriteria approach to climate policy vis-A -vis terrestrial ecosystems are then explored through two hypothetical case study examples. The paper closes with a brief discussion of the utility of the multi-criteria approach in the context of other climate policy evaluation approaches, considers lessons learned as a result efforts to evaluate climate policy in the realm of terrestrial ecosystems, and reiterates the role of ecosystem resilience in creating sound policies and actions that support the integration of climate change and development goals.

  19. Hydroelectric power in Switzerland: large growth potential by increasing the installed power

    International Nuclear Information System (INIS)

    Schleiss, A.

    2007-01-01

    Due to its important hydroelectric power generation facilities (about 525 plants with a total power of 13,314 MW producing about 35.3 TWh annually) Switzerland plays an important role in the interconnected European power system. Large artificial storage lakes in the Swiss Alps can generate peak power during hours of highest demand: 9700 MW are available from accumulated energy and the total power of pumped-storage facilities amounts to 1700 MW. The latter allow refilling the reservoirs at periods of low power demand and generating power at periods of peak demand. In the case of favorable conditions, the yearly average power production could be increased by 6% and the production during the winter period (October to March) by 20% by the year 2020. However, looking forward to the year 2050, the annual production is expected to decrease by 3% despite a possible extension of hydropower. This decrease is due to the enforcement of the minimum residual water flow rates required by a new legislation to protect the rivers. The enforcement is due at latest when the present licenses for water utilization expire. On the other hand, the installed (peak) power might be further increased by 50% by retrofitting the existing installations and constructing the pumped-storage plants currently at the planning stage

  20. Potential future scenarios for Australia's native biodiversity given on-going increases in human population.

    Science.gov (United States)

    Pepper, D A; Lada, Hania; Thomson, James R; Bakar, K Shuvo; Lake, P S; Mac Nally, Ralph

    2017-01-15

    Most natural assets, including native biodiversity (our focus), are under increasing threat from direct (loss of habitat, hunting) and indirect (climate change) human actions. Most human impacts arise from increasing human populations coupled with rises in per capita resource use. The rates of change of human actions generally outpace those to which the biota can respond or adapt. If we are to maintain native biodiversity, then we must develop ways to envisage how the biota may be affected over the next several decades to guide management and policy responses. We consider the future for Australia's native biodiversity in the context of two assumptions. First, the human population in Australia will be 40million by 2050, which has been mooted by federal government agencies. Second, greenhouse gas emissions will track the highest rates considered by the Intergovernmental Panel on Climate Change. The scenarios are based on major drivers of change, which were constructed from seven key drivers of change pertinent to native biodiversity. Five scenarios deal with differing distributions of the human population driven by uncertainties in climate change and in the human responses to climate change. Other scenarios are governed largely by global change and explore different rates of resource use, unprecedented rates of technological change, capabilities and societal values. A narrative for each scenario is provided. The set of scenarios spans a wide range of possible future paths for Australia, with different implications for the future of native biodiversity. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. GM trees with increased resistance to herbivores: trait efficiency and their potential to promote tree growth

    Directory of Open Access Journals (Sweden)

    Joakim eHjältén

    2015-05-01

    Full Text Available Climate change, as well as a more intensive forestry, is expected to increase the risk of damage by pests and pathogens on trees, which can already be a severe problem in tree plantations. Recent development of biotechnology theoretically allows for resistance enhancement that could help reduce these risks but we still lack a comprehensive understanding of benefits and tradeoffs with pest resistant GM (genetically modified trees. We synthesized the current knowledge on the effectiveness of GM forest trees with increased resistance to herbivores. There is ample evidence that induction of exogenous Bacillus thuringiensis genes reduce performance of target pests whereas upregulation of endogenous resistance traits e.g. phenolics, generates variable results. Our review identified very few studies estimating the realized benefits in tree growth of GM trees in the field. This is concerning as the realized benefit with insect resistant GM plants seems to be context-dependent and likely manifested only if herbivore pressure is sufficiently high. Future studies of secondary pest species and resistance evolution in pest to GM trees should be prioritized. But most importantly we need more long-term field tests to evaluate the benefits and risks with pest resistant GM trees.

  2. Prospective audit to evaluate the potential of the coronial system to increase solid organ donation.

    Science.gov (United States)

    Twamley, Huw; Haigh, Andrew; Williment, Claire; Hudson, Cara; Whitney, Julie; Neuberger, James

    2016-07-08

    Anecdotal evidence suggests that organ donation from deceased donors referred to the Coroner/Procurator Fiscal (PF) could be increased if all followed best practice. The aim of this prospective audit was to establish how referrals affected organ donation and to develop evidence-based guidelines to ensure that organ donation can be facilitated safely without interfering in the Coroner/PF's investigative process. Prospective audit. All acute National Health Service Hospitals in the UK where deceased organ donation was considered. 1437 deceased patients who met the eligibility criteria for organ donation and were referred to Coroner/PF. Number of cases where permission for transplantation was given, number of organs where permission was refused and number of organs which might have been transplanted if all had followed best practice. Full permission for organ retrieval was given in 87% cases and partial permission in 9%. However, if full permission had been given where no autopsy was performed or restrictions seemed unjustified, up to 77 organs (22 lungs, 22 kidneys, 9 pancreases, 9 livers, 8 hearts and 7 small bowels) could have been available for transplant. Coroners/PFs and their officers show strong support for transplantation but improvement in practice could result in a small but significant increase in life-saving and life-enhancing transplants. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  3. Increasing medical students' engagement in public health: case studies illustrating the potential role of online learning.

    Science.gov (United States)

    Sheringham, J; Lyon, A; Jones, A; Strobl, J; Barratt, H

    2016-09-01

    The value of e-learning in medical education is widely recognized but there is little evidence of its value in teaching medical students about public health. Such evidence is needed because medical students' engagement with public health has been low. We present three recent case studies from UK medical schools to illustrate diverse ways in which online approaches can increase medical students' engagement with learning public health. A comparative case study approach was used applying quantitative and qualitative data to examine engagement in terms of uptake/use amongst eligible students, acceptability and perceived effectiveness using an analytic framework based on Seven Principles of Effective Teaching. Across the three case studies, most (67-85%) eligible students accessed online materials, and rated them more favourably than live lectures. Students particularly valued opportunities to use e-learning flexibly in terms of time and place. Online technologies offered new ways to consolidate learning of key public health concepts. Although students found contributing to online discussions challenging, it provided opportunities for students to explore concepts in depth and enabled students that were uncomfortable speaking in face-to-face discussions to participate. E-learning can be applied in diverse ways that increase medical student engagement with public health teaching. © The Author 2015. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Increased preference of surface ablation over laser in situ keratomileusis between 2008–2011 is correlated to risk of ecatasia

    Directory of Open Access Journals (Sweden)

    Moisseiev E

    2013-01-01

    Full Text Available Elad Moisseiev,1,3 Tzahi Sela,2 Liza Minkev,2 David Varssano1,31Department of Ophthalmology, Tel-Aviv Medical Center, Tel-Aviv, Israel; 2Care Vision, Tel Aviv, Israel; 3Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, IsraelPurpose: To evaluate the trends in corneal refractive procedure selection for the correction of myopia, focusing on the relative proportions of laser in situ keratomileusis (LASIK and surface ablation procedures.Methods: Only eyes that underwent LASIK or surface ablation for the correction of myopia between 2008–2011 were included in this retrospective study. Additional recorded parameters included patient age, preoperative manifest refraction, corneal thickness, and calculated residual corneal bed thickness. A risk score was given to each eye, based on these parameters, according to the Ectasia Risk Factor Score System (ERFSS, without the preoperative corneal topography.Results: This study included 16,163 eyes, of which 38.4% underwent LASIK and 61.6% underwent surface ablation. The risk score correlated with procedure selection, with LASIK being preferred in eyes with a score of 0 and surface ablation in eyes with a score of 2 or higher. When controlling for age, preoperative manifest refraction, corneal thickness, and all parameters, the relative proportion of surface ablation compared with LASIK was found to have grown significantly during the study period.Conclusions: Our results indicate that with time, surface ablation tended to be performed more often than LASIK for the correction of myopia in our cohort. Increased awareness of risk factors and preoperative risk assessment tools, such as the ERFSS, have shifted the current practice of refractive surgery from LASIK towards surface ablation despite the former's advantages, especially in cases in which the risk for ectasia is more than minimal (risk score 2 and higher.Keywords: surface ablation, LASIK, PRK, myopia correction, ectasia

  5. Using 3D Printers to Model Earth Surface Topography for Increased Student Understanding and Retention

    Science.gov (United States)

    Thesenga, David; Town, James

    2014-05-01

    In February 2000, the Space Shuttle Endeavour flew a specially modified radar system during an 11-day mission. The purpose of the multinational Shuttle Radar Topography Mission (SRTM) was to "obtain elevation data on a near-global scale to generate the most complete high-resolution digital topographic database of Earth" by using radar interferometry. The data and resulting products are now publicly available for download and give a view of the landscape removed of vegetation, buildings, and other structures. This new view of the Earth's topography allows us to see previously unmapped or poorly mapped regions of the Earth as well as providing a level of detail that was previously unknown using traditional topographic mapping techniques. Understanding and appreciating the geographic terrain is a complex but necessary requirement for middle school aged (11-14yo) students. Abstract in nature, topographic maps and other 2D renderings of the Earth's surface and features do not address the inherent spatial challenges of a concrete-learner and traditional methods of teaching can at times exacerbate the problem. Technological solutions such as 3D-imaging in programs like Google Earth are effective but lack the tactile realness that can make a large difference in learning comprehension and retention for these young students. First developed in the 1980's, 3D printers were not commercial reality until recently and the rapid rise in interest has driven down the cost. With the advent of sub US1500 3D printers, this technology has moved out of the high-end marketplace and into the local office supply store. Schools across the US and elsewhere in the world are adding 3D printers to their technological workspaces and students have begun rapid-prototyping and manufacturing a variety of projects. This project attempted to streamline the process of transforming SRTM data from a GeoTIFF format by way of Python code. The resulting data was then inputted into a CAD-based program for

  6. Potential effects of climate change on surface-water quality in North America

    Science.gov (United States)

    Murdoch, Peter S.; Baron, Jill S.; Miller, T.L.

    2000-01-01

    Data from long-term ecosystem monitoring and research stations in North America and results of simulations made with interpretive models indicate that changes in climate (precipitation and temperature) can have a significant effect on the quality of surface waters. Changes in water quality during storms, snowmelt, and periods of elevated air temperature or drought can cause conditions that exceed thresholds of ecosystem tolerance and, thus, lead to water-quality degradation. If warming and changes in available moisture occur, water-quality changes will likely first occur during episodes of climate-induced stress, and in ecosystems where the factors controlling water quality are sensitive to climate variability. Continued climate stress would increase the frequency with which ecosystem thresholds are exceeded and thus lead to chronic water-quality changes. Management strategies in a warmer climate will therefore be needed that are based on local ecological thresholds rather than annual median condition. Changes in land use alter biological, physical, and chemical processes in watersheds and thus significantly alter the quality of adjacent surface waters; these direct human-caused changes complicate the interpretation of water-quality changes resulting from changes in climate, and can be both mitigated and exacerbated by climate change. A rigorous strategy for integrated, long-term monitoring of the ecological and human factors that control water quality is necessary to differentiate between actual and perceived climate effects, and to track the effectiveness of our environmental policies.

  7. Dangerous dining: surface foraging of North Atlantic right whales increases risk of vessel collisions.

    Science.gov (United States)

    Parks, Susan E; Warren, Joseph D; Stamieszkin, Karen; Mayo, Charles A; Wiley, David

    2012-02-23

    North Atlantic right whales are critically endangered and, despite international protection from whaling, significant numbers die from collisions with ships. Large groups of right whales migrate to the coastal waters of New England during the late winter and early spring to feed in an area with large numbers of vessels. North Atlantic right whales have the largest per capita record of vessel strikes of any large whale population in the world. Right whale feeding behaviour in Cape Cod Bay (CCB) probably contributes to risk of collisions with ships. In this study, feeding right whales tagged with archival suction cup tags spent the majority of their time just below the water's surface where they cannot be seen but are shallow enough to be vulnerable to ship strike. Habitat surveys show that large patches of right whale prey are common in the upper 5 m of the water column in CCB during spring. These results indicate that the typical spring-time foraging ecology of right whales may contribute to their high level of mortality from vessel collisions. The results of this study suggest that remote acoustic detection of prey aggregations may be a useful supplement to the management and conservation of right whales.

  8. Knowledge brokerage - potential for increased capacities and shared power in impact assessment

    International Nuclear Information System (INIS)

    Rosario Partidario, Maria; Sheate, William R.

    2013-01-01

    Constructive and collaborative planning theory has exposed the perceived limitations of public participation in impact assessment. At strategic levels of assessment the established norm can be misleading and practice is illusive. For example, debates on SEA effectiveness recognize insufficiencies, but are often based on questionable premises. The authors of this paper argue that public participation in strategic assessment requires new forms of information and engagement, consistent with the complexity of the issues at these levels and that strategic assessments can act as knowledge brokerage instruments with the potential to generate more participative environments and attitudes. The paper explores barriers and limitations, as well as the role of knowledge brokerage in stimulating the engagement of the public, through learning-oriented processes and responsibility sharing in more participative models of governance. The paper concludes with a discussion on building and inter-change of knowledge, towards creative solutions to identified problems, stimulating learning processes, largely beyond simple information transfer mechanisms through consultative processes. The paper argues fundamentally for the need to conceive strategic assessments as learning platforms and design knowledge brokerage opportunities explicitly as a means to enhance learning processes and power sharing in IA. - Highlights: ► Debates on SEA recognize insufficiencies on public participation ► We propose new forms of engagement consistent with complex situations at strategic levels of decision-making ► Constructive and collaborative planning theories help explain how different actors acquire knowledge and the value of knowledge exchange ► Strategic assessments can act as knowledge brokerage instruments ► The paper argues for strategic assessments as learning platforms as a means to enhance learning processes and power sharing in IA.

  9. Television in the bedroom and increased body weight: potential explanations for their relationship among European schoolchildren.

    Science.gov (United States)

    Cameron, A J; van Stralen, M M; Brug, J; Salmon, J; Bere, E; Chinapaw, M J M; De Bourdeaudhuij, I; Jan, N; Manios, Y; Moreno, L A; Velde, S J

    2013-04-01

    A television in the bedroom is associated with measures of adiposity. We aimed to test if this association is mediated by any of (i) time spent watching television, (ii) sleep duration, (iii) physical activity level or (iv) consumption of soft drinks. Data were from 7234 boys and girls aged 10-12 years in European countries involved in the EuropeaN Energy balance Research to prevent excessive weight Gain among Youth project (Belgium, Greece, Hungary, the Netherlands, Norway, Slovenia and Spain). Waist circumference, height and weight were measured. The presence of a bedroom television, television viewing time, sleep duration, physical activity time and soft drink consumption were assessed by standardized questionnaires. Almost 40% of schoolchildren had a bedroom television, with the highest percentage among Hungarian children (65%) and lowest for Belgian, Slovenian and Spanish children (all ≈28%). A television in the bedroom was positively associated with time spent watching television, soft drink consumption and overweight and obesity (all P television in the bedroom and measures of body size was partly mediated by total television viewing time (proportion mediated for waist circumference 8.9%; for body mass index 8.3%) but not sleep duration, physical activity time or soft drink consumption. The strong association between a television in the bedroom and adiposity was at least partially mediated by television viewing time. The large proportion of European schoolchildren with a television in their bedroom is of concern. Parents should be aware of the potential consequences when placing a television in a child's bedroom and children should limit viewing time. © 2012 The Authors. Pediatric Obesity © 2012 International Association for the Study of Obesity.

  10. Tempol-nebivolol therapy potentiates hypotensive effect increasing NO bioavailability and signaling pathway.

    Science.gov (United States)

    Bertera, F M; Santa-Cruz, D M; Balestrasse, K B; Gorzalczany, S B; Höcht, C; Taira, C A; Polizio, A H

    2014-02-01

    Nebivolol is a third generation beta blocker with endothelial nitric oxide synthase (eNOS) agonist properties. Considering the role of reactive oxygen species (ROS) in the uncoupling of eNOS, we hypothesized that the preadministration of an antioxidant as tempol, could improve the hypotensive response of nebivolol in normotensive animals increasing the nitric oxide (NO) bioavailability by a reduction of superoxide (O2(•-)) basal level production in the vascular tissue. Male Sprague Dawley rats were given tap water to drink (control group) or tempol (an antioxidant scavenger of superoxide) for 1 week. After 1 week, Nebivolol, at a dose of 3 mg/kg, was injected intravenously to the control group or to the tempol-treated group. Mean arterial pressure, heart rate, and blood pressure variability were evaluated in the control, tempol, nebivolol, and tempol nebivolol groups, as well as, the effect of different inhibitor as Nβ-nitro-l-arginine methyl ester (L-NAME, a Nitric oxide synthase blocker) or glybenclamide, a KATP channel inhibitor. Also, the expression of α,β soluble guanylate cyclase (sGC), phospho-eNOS, and phospho-vasodilator-stimulated phosphoprotein (P-VASP) were evaluated by Western Blot and cyclic guanosine monophosphate (cGMP) levels by an enzyme-linked immunosorbent assay (ELISA) commercial kit assay. We showed that pretreatment with tempol in normotensive rats produces a hypotensive response after nebivolol administration through an increase in the NO bioavailability and sGC, improving the NO/cGMP/protein kinase G (PKG) pathway compared to that of the nebivolol group. We demonstrated that tempol preadministration beneficiates the response of a third-generation beta blocker with eNOS stimulation properties, decreasing the basal uncoupling of eNOS, and improving NO bioavailability. Our results clearly open a possible new strategy therapeutic for treating hypertension.

  11. Potential of Multitemporal Tandem-X Derived Crop Surface Models for Maize Growth Monitoring

    Science.gov (United States)

    Hütt, C.; Tilly, N.; Schiedung, H.; Bareth, G.

    2016-06-01

    In this study, first results of retrieving plant heights of maize fields from multitemporal TanDEM-X images are shown. Three TanDEM-X dual polarization spotlight acquisitions were taken over a rural area in Germany in the growing season 2014. By interferometric processing, digital terrain models (DTM) were derived for each date with 5m resolution. From the data of the first acquisition (June 1st) taken before planting, a DTM of the bare ground is generated. The data of the following acquisition dates (July 15th, July 26th) are used to establish crop surface models (CSM). A CSM represents the crop surface of a whole field in a high resolution. By subtracting the DTM of the ground from each CSM, the actual plant height is calculated. Within these data sets 30 maize fields in the area of interest could be detected and verified by external land use data. Besides the spaceborne measurements, one of the maize fields was intensively investigated using terrestrial laser scanning (TLS), which was carried out at the same dates as the predicted TanDEM-X acquisitions. Visual inspection of the derived plant heights, and accordance of the individually processed polarisations over the maize fields, demonstrate the feasibility of the proposed method. Unfortunately, the infield variability of the intensively monitored field could not be successfully captured in the TanDEM-X derived plant heights and merely the general trend is visible. Nevertheless, the study shows the potential of the TanDEM-X constellation for maize height monitoring on field level.

  12. Potential evaporation estimation through an unstressed surface energy balance and its sensitivity to climate change

    Science.gov (United States)

    Barella-Ortiz, A.; Polcher, J.; Tuzet, A.; Laval, K.

    2013-06-01

    Potential evaporation (ETP) is a basic input for hydrological and agronomic models, as well as a key variable in most actual evaporation estimations. It has been approached through several diffusive and energy balance methods, out of which the Penman-Monteith equation is recommended as the standard one. In order to deal with the diffusive approach, ETP must be estimated at a sub-diurnal frequency, as currently done in land surface models (LSM). This study presents an improved method, developed in the ORCHIDEE LSM, which consists in estimating ETP through an unstressed surface energy balance (USEB method). The results confirm the quality of the estimation which is currently implemented in the model (Milly, 1992). ETP has also been estimated using a reference equation (computed at a daily time step) provided by the Food and Agriculture Organization (FAO). First, a comparison for a reference period under current climate conditions, shows that both formulations differ, specially in arid areas. However, they supply similar values when FAO's assumption of neutral stability conditions is relaxed, by replacing FAO's aerodynamic resistance by the model's one. Furthermore, if the vapour pressure deficit (VPD) estimated for FAO's equation, is substituted by ORCHIDEE's VPD or its humidity gradient, the daily mean estimate is further improved. In a second step, ETP's sensitivity to climate change is assessed comparing trends in both formulations for the 21st Century. It is found that the USEB method shows a higher sensitivity. Both VPD and the model's humidity gradient, as well as the aerodynamic resistance have been identified as key parameters in governing ETP trends. Finally, the sensitivity study is extended to three empirical approximations based on temperature, net radiation and mass transfer (Hargreaves, Priestley-Taylor and Rohwer, respectively). The sensitivity of these methods is compared to the USEB method's one to test if simplified equations are able to reproduce

  13. Central Sensitization of Mechanical Nociceptive Pathways Is Associated with a Long-Lasting Increase of Pinprick-Evoked Brain Potentials.

    Science.gov (United States)

    van den Broeke, Emanuel N; Lambert, Julien; Huang, Gan; Mouraux, André

    2016-01-01

    Intense or sustained nociceptor activation, occurring, for example, after skin injury, can induce "central sensitization," i.e., an increased responsiveness of nociceptive neurons in the central nervous system. A hallmark of central sensitization is increased mechanical pinprick sensitivity in the area surrounding the injured skin. The aim of the present study was to identify changes in brain activity related to this increased pinprick sensitivity. In 20 healthy volunteers, increased pinprick sensitivity was induced using high frequency electrical stimulation of the forearm skin (HFS). Mechanical pinprick stimulation (64 and 90 mN) was used to elicit event-related brain potentials (ERPs). The recordings were performed before, 20 min after and 45 min after applying HFS. The contralateral non-sensitized arm served as control. Pinprick stimulation of 64 mN, but not 90 mN, applied in the area of increased pinprick sensitivity elicited a significant increase of a late-latency positive wave, between 300 and 1100 ms after stimulus onset and was maximal at midline posterior electrodes. Most importantly, this