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Sample records for elemental ions released

  1. Composite oxygen ion transport element

    DOEpatents

    Chen, Jack C.; Besecker, Charles J.; Chen, Hancun; Robinson, Earil T.

    2007-06-12

    A composite oxygen ion transport element that has a layered structure formed by a dense layer to transport oxygen ions and electrons and a porous support layer to provide mechanical support. The dense layer can be formed of a mixture of a mixed conductor, an ionic conductor, and a metal. The porous support layer can be fabricated from an oxide dispersion strengthened metal, a metal-reinforced intermetallic alloy, a boron-doped Mo.sub.5Si.sub.3-based intermetallic alloy or combinations thereof. The support layer can be provided with a network of non-interconnected pores and each of said pores communicates between opposite surfaces of said support layer. Such a support layer can be advantageously employed to reduce diffusion resistance in any type of element, including those using a different material makeup than that outlined above.

  2. FORTE antenna element and release mechanism design

    NASA Technical Reports Server (NTRS)

    Rohweller, David J.; Butler, Thomas A.

    1995-01-01

    The Fast On-Orbit Recording of Transient Events (FORTE) satellite being built by Los Alamos National Laboratory (LANL) and Sandia National Laboratories (SNL) has as its most prominent feature a large deployable (11 m by 5 m) log periodic antenna to monitor emissions from electrical storms on the Earth. This paper describes the antenna and the design for the long elements and explains the dynamics of their deployment and the damping system employed. It also describes the unique paraffin-actuated reusable tie-down and release mechanism employed in the system.

  3. FORTE antenna element and release mechanism design

    SciTech Connect

    Rohweller, D.J.; Butler, T.Af.

    1995-02-01

    The Fast On-Orbit Recording of Transient Events (FORTE) satellite being built by Los Alamos National Laboratory (LANL) and Sandia National Laboratories (SNL) has as its most prominent feature a large deployable (11 m by 5 m) log periodic antenna to monitor emissions from electrical storms on the Earth. This paper describes the antenna and the design for the long elements and explains the dynamics of their deployment and the damping system employed. It also describes the unique paraffin-actuated reusable tie-down and release mechanism employed in the system.

  4. Ion processing element with composite media

    DOEpatents

    Mann, Nick R.; Tranter, Troy J.; Todd, Terry A.; Sebesta, Ferdinand

    2009-03-24

    An ion processing element employing composite media disposed in a porous substrate, for facilitating removal of selected chemical species from a fluid stream. The ion processing element includes a porous fibrous glass substrate impregnated by composite media having one or more active components supported by a matrix material of polyacrylonitrile. The active components are effective in removing, by various mechanisms, one or more constituents from a fluid stream passing through the ion processing element. Due to the porosity and large surface area of both the composite medium and the substrate in which it is disposed, a high degree of contact is achieved between the active component and the fluid stream being processed. Further, the porosity of the matrix material and the substrate facilitates use of the ion processing element in high volume applications where it is desired to effectively process a high volume flows.

  5. Ion processing element with composite media

    DOEpatents

    Mann, Nick R.; Tranter, Troy J.; Todd, Terry A.; Sebesta, Ferdinand

    2003-02-04

    An ion processing element employing composite media disposed in a porous substrate, for facilitating removal of selected chemical species from a fluid stream. The ion processing element includes a porous fibrous glass substrate impregnated by composite media having one or more active components supported by a matrix material of polyacrylonitrile. The active components are effective in removing, by various mechanisms, one or more constituents from a fluid stream passing through the ion processing element. Due to the porosity and large surface area of both the composite medium and the substrate in which it is disposed, a high degree of contact is achieved between the active component and the fluid stream being processed. Further, the porosity of the matrix material and the substrate facilitates use of the ion processing element in high volume applications where it is desired to effectively process a high volume flows.

  6. Plasma immersion ion implantation for reducing metal ion release

    SciTech Connect

    Diaz, C.; Garcia, J. A.; Maendl, S.; Pereiro, R.; Fernandez, B.; Rodriguez, R. J.

    2012-11-06

    Plasma immersion ion implantation of Nitrogen and Oxygen on CoCrMo alloys was carried out to improve the tribological and corrosion behaviors of these biomedical alloys. In order to optimize the implantation results we were carried experiments at different temperatures. Tribocorrosion tests in bovine serum were used to measure Co, Cr and Mo releasing by using Inductively Coupled Plasma Mass Spectrometry analysis after tests. Also, X-ray Diffraction analysis were employed in order to explain any obtained difference in wear rate and corrosion tests. Wear tests reveals important decreases in rate of more than one order of magnitude for the best treatment. Moreover decreases in metal release were found for all the implanted samples, preserving the same corrosion resistance of the unimplanted samples. Finally this paper gathers an analysis, in terms of implantation parameters and achieved properties for industrial implementation of these treatments.

  7. Synthesis and release of trace elements from hollow and porous hydroxyapatite spheres

    NASA Astrophysics Data System (ADS)

    Xia, Wei; Grandfield, Kathryn; Schwenke, Almut; Engqvist, Håkan

    2011-07-01

    It is known that organic species regulate fabrication of hierarchical biological forms via solution methods. However, in this study, we observed that the presence of inorganic ions plays an important role in the formation and regulation of biological spherical hydroxyapatite formation. We present a mineralization method to prepare ion-doped hydroxyapatite spheres with a hierarchical structure that is free of organic surfactants and biological additives. Porous and hollow strontium-doped hydroxyapatite spheres were synthesized via controlling the concentration of strontium ions in a calcium and phosphate buffer solution. Similarly, fluoride and silicon-doped hydroxyapatite spheres were synthesized. While spherical particle formation was attainable at low and high temperature for Sr-doped hydroxyapatite, it was only possible at high temperature in the F/Si-doped system. The presence of inorganic ions not only plays an important role in the formation and regulation of biological spherical hydroxyapatite, but also could introduce pharmaceutical effects as a result of trace element release. Such ion release results showed a sustained release with pH responsive behavior, and significantly influenced the hydroxyapatite re-precipitation. These ion-doped hydroxyapatite spheres with hollow and porous structure could have promising applications as bone/tooth materials, drug delivery systems, and chromatography supports.

  8. Release of metal ions from orthodontic appliances: an in vitro study.

    PubMed

    Mikulewicz, Marcin; Chojnacka, Katarzyna; Woźniak, Barbara; Downarowicz, Patrycja

    2012-05-01

    In this paper, we report the results of an in vitro experiment on the release of metal ions from orthodontic appliances composed of alloys containing iron, chromium, nickel, silicon, and molybdenum into artificial saliva. The concentrations of magnesium, aluminum, silicon, phosphorus, sulfur, potassium, calcium, titanium, vanadium, manganese, iron, cobalt, copper, zinc, nickel, and chromium were significantly higher in artificial saliva in which metal brackets, bands, and wires used in orthodontics were incubated. In relation to the maximum acceptable concentrations of metal ions in drinking water and to recommended daily doses, two elements of concern were nickel (573 vs. 15 μg/l in the controls) and chromium (101 vs. 8 μg/l in the controls). Three ion release coefficients were defined: α, a dimensionless multiplication factor; β, the difference in concentrations (in micrograms per liter); and γ, the ion release coefficient (in percent). The elevated levels of metals in saliva are thought to occur by corrosion of the chemical elements in the alloys or welding materials. The concentrations of some groups of dissolved elements appear to be interrelated. PMID:22011837

  9. Micro faraday-element array detector for ion mobility spectroscopy

    DOEpatents

    Gresham, Christopher A.; Rodacy, Phillip J.; Denton, M. Bonner; Sperline, Roger

    2004-10-26

    An ion mobility spectrometer includes a drift tube having a collecting surface covering a collecting area at one end of the tube. The surface comprises a plurality of closely spaced conductive elements on a non-conductive substrate, each conductive element being electrically insulated from each other element. A plurality of capacitive transimpedance amplifiers (CTIA) adjacent the collecting surface are electrically connected to the plurality of elements, so charge from an ion striking an element is transferred to the capacitor of the connected CTIA. A controller counts the charge on the capacitors over a period of time.

  10. Helium-ion-induced release of hydrogen from graphite

    SciTech Connect

    Langley, R.A.

    1987-01-01

    The ion-induced release of hydrogen from AXF-5Q graphite was studied for 350-eV helium ions. The hydrogen was implanted into the graphite with a low energy (approx.200 eV) and to a high fluence. This achieved a thin (approx.10-nm), saturated near-surface region. The release of hydrogen was measured as a function of helium fluence. A model that includes ion-induced detrapping, retrapping, and surface recombination was used to analyze the experimental data. A value of (1.65 +- 0.2) x 10/sup -16/ cm/sup 2/ was obtained from the detrapping cross section, and a value of (0.5 to 4) x 10/sup -14/ cm/sup 4//atoms was obtained for the recombination coefficient. 11 refs., 4 figs.

  11. Zoledronate and Ion-releasing Resins Impair Dentin Collagen Degradation

    PubMed Central

    Tezvergil-Mutluay, A.; Seseogullari-Dirihan, R.; Feitosa, V.P.; Tay, F.R.; Watson, T.F.; Pashley, D.H.; Sauro, S.

    2014-01-01

    This study analyzed the amounts of solubilized telopeptides cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and C-terminal crosslinked telopeptide of type I collagen (CTX) derived from matrix-metalloproteinases (MMPs) and cysteine cathepsins (CTPs) subsequent to application of a filler-free (Res.A) or an ion-releasing resin (Res.B) to ethylenediaminetetraacetic acid (EDTA)-demineralized dentin with or without zoledronate-containing primer (Zol-primer) pre-treatment. The chemical modification induced following treatments and artificial saliva (AS) storage was also analyzed through attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Totally EDTA-demineralized specimens were infiltrated with Res.A or Res.B with or without Zol-primer pre-treatment, light-cured, and immersed in AS for up to 4 wk. ICTP release was reduced following infiltration with Res.B and further reduced when Res.B was used with Zol-primer; remarkable phosphate mineral uptake was attained after AS storage. CTX release was increased in Res.A- and Res.B-treated dentin. However, when Zol-primer was used with Res.A, the CTX release fell significantly compared to the other tested resin-infiltration methods. In conclusion, zoledronate offers an additional inhibitory effect to the ion-releasing resins in MMP-mediated collagen degradation. However, Zol-primer induces a modest reduction in CTX release only when used with resin-based systems containing no ion-releasing fillers. PMID:25074494

  12. Zoledronate and ion-releasing resins impair dentin collagen degradation.

    PubMed

    Tezvergil-Mutluay, A; Seseogullari-Dirihan, R; Feitosa, V P; Tay, F R; Watson, T F; Pashley, D H; Sauro, S

    2014-10-01

    This study analyzed the amounts of solubilized telopeptides cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and C-terminal crosslinked telopeptide of type I collagen (CTX) derived from matrix-metalloproteinases (MMPs) and cysteine cathepsins (CTPs) subsequent to application of a filler-free (Res.A) or an ion-releasing resin (Res.B) to ethylenediaminetetraacetic acid (EDTA)-demineralized dentin with or without zoledronate-containing primer (Zol-primer) pre-treatment. The chemical modification induced following treatments and artificial saliva (AS) storage was also analyzed through attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Totally EDTA-demineralized specimens were infiltrated with Res.A or Res.B with or without Zol-primer pre-treatment, light-cured, and immersed in AS for up to 4 wk. ICTP release was reduced following infiltration with Res.B and further reduced when Res.B was used with Zol-primer; remarkable phosphate mineral uptake was attained after AS storage. CTX release was increased in Res.A- and Res.B-treated dentin. However, when Zol-primer was used with Res.A, the CTX release fell significantly compared to the other tested resin-infiltration methods. In conclusion, zoledronate offers an additional inhibitory effect to the ion-releasing resins in MMP-mediated collagen degradation. However, Zol-primer induces a modest reduction in CTX release only when used with resin-based systems containing no ion-releasing fillers. PMID:25074494

  13. Multitude of ion channels in the regulation of transmitter release.

    PubMed Central

    Rahamimoff, R; Butkevich, A; Duridanova, D; Ahdut, R; Harari, E; Kachalsky, S G

    1999-01-01

    The presynaptic nerve terminal is of key importance in communication in the nervous system. Its primary role is to release transmitter quanta on the arrival of an appropriate stimulus. The structural basis of these transmitter quanta are the synaptic vesicles that fuse with the surface membrane of the nerve terminal, to release their content of neurotransmitter molecules and other vesicular components. We subdivide the control of quantal release into two major classes: the processes that take place before the fusion of the synaptic vesicle with the surface membrane (the pre-fusion control) and the processes that occur after the fusion of the vesicle (the post-fusion control). The pre-fusion control is the main determinant of transmitter release. It is achieved by a wide variety of cellular components, among them the ion channels. There are reports of several hundred different ion channel molecules at the surface membrane of the nerve terminal, that for convenience can be grouped into eight major categories. They are the voltage-dependent calcium channels, the potassium channels, the calcium-gated potassium channels, the sodium channels, the chloride channels, the non-selective channels, the ligand gated channels and the stretch-activated channels. There are several categories of intracellular channels in the mitochondria, endoplasmic reticulum and the synaptic vesicles. We speculate that the vesicle channels may be of an importance in the post-fusion control of transmitter release. PMID:10212476

  14. In vitro prominent bone regeneration by release zinc ion from Zn-modified implant

    SciTech Connect

    Yusa, Kazuyuki; Yamamoto, Osamu; Fukuda, Masayuki; Koyota, Souichi; Koizumi, Yukio; Sugiyama, Toshihiro

    2011-08-26

    Highlights: {yields} We isolated the Zn{sup 2+} ions (eluted Zn{sup 2+} ion; EZ) from zinc-incorporated titanium implant. {yields} The EZ promoted the cell viability in hBMCs. {yields} The EZ stimulated preosteoblast and osteoblast marker gene expression in hBMCs. {yields} The hBMCs supplemented with EZ showed typically cell morphology when osteoblast maturing. {yields} It is revealed that the EZ also stimulates the calcium deposition of hBMCs. -- Abstract: Zinc is one of the trace elements which induce the proliferation and the differentiation of the osteoblast. In the previous study, we found that zinc ions (Zn{sup 2+} ion)-releasing titanium implants had excellent bone fixation using a rabbit femurs model. In this study, we isolated the Zn{sup 2+} ions (eluted Zn{sup 2+} ion; EZ) released from the implant surface, and evaluated the effect of EZ on the osteogenesis of human bone marrow-derived mesenchymal cells (hBMCs). In the result, it was found that the EZ stimulated cell viability, osteoblast marker gene (type I collagen, osteocalcin (OC), alkaline phosphatase (ALP) and bone sialoprotein (BSP)) expressions and calcium deposition in hBMCs.

  15. Elemental microanalysis in ecophysiology using ion microbeam

    NASA Astrophysics Data System (ADS)

    Przybyłowicz, W. J.; Mesjasz-Przybyłowicz, J.; Migula, P.; Turnau, K.; Nakonieczny, M.; Augustyniak, M.; Głowacka, E.

    2004-06-01

    A few recent applications of elemental microanalysis based on proton beam in ecophysiology and ecotoxicology are shown. They are related to biofiltering capabilities of mycorrhiza (symbiosis between fungi and plant roots) and to plant-insect herbivore interactions. The reported results were obtained at iThemba LABS, South Africa. PIXE and BS techniques were simultaneously used. True elemental maps were generated using a VMS version and PC version of GeoPIXE (GeoPIXE I and II). Further analysis was performed using PIXE and BS spectra extracted from list-mode data and corresponding to specific organs of an insect or a plant.

  16. Fluoride and aluminum release from restorative materials using ion chromatography

    PubMed Central

    OKTE, Zeynep; BAYRAK, Sule; FIDANCI, Ulvi Reha; SEL, Tevhide

    2012-01-01

    Objective The aim of this study was to determine the amounts of fluoride and aluminum released from different restorative materials stored in artificial saliva and double-distilled water. Material and Methods Cylindrical specimens (10 x 1 mm) were prepared from 4 different restorative materials (Kavitan Plus, Vitremer, Dyract Extra, and Surefil). For each material, 20 specimens were prepared, 10 of which were stored in 5 mL artificial saliva and 10 of which were stored in 5 mL of double-distilled water. Concentrations of fluoride and aluminum in the solutions were measured using ion chromatography. Measurements were taken daily for one week and then weekly for two additional weeks. Data were analyzed using two-way ANOVA and Duncan's multiple range tests (p<0.05). Results The highest amounts of both fluoride and aluminum were released by the resin-modified glass ionomer cement Vitremer in double-distilled water (p<0.05). All materials released significantly more fluoride in double-distilled water than in artificial saliva (p<0.05). In artificial saliva, none of the materials were observed to release aluminum. Conclusion It was concluded that storage media and method of analysis should be taken into account when the fluoride and aluminum release from dental materials is assessed. PMID:22437674

  17. Experimental composite guidance conduits for peripheral nerve repair: an evaluation of ion release.

    PubMed

    Zhang, X F; Coughlan, A; O'Shea, H; Towler, M R; Kehoe, S; Boyd, D

    2012-08-01

    Poly (lactide-co-glycolide) (PLGA) - Pluronic F127 - glass composites have demonstrated excellent potential, from the perspective of controlled mechanical properties and cytocompatibility, for peripheral nerve regeneration. In addition to controlling the mechanical properties and cytotoxicity for such composite devices, the glass component may mediate specific responses upon implantation via degradation in the physiological environment and release of constituent elements. However, research focused on quantifying the release levels of such therapeutic ions from these experimental medical devices has been limited. To redress the balance, this paper explores the ion release profiles for Si(4+), Ca(2+), Na(+), Zn(2+), and Ce(4+) from experimental composite nerve guidance conduits (CNGC) comprising PLGA (at 12.5, and 20 wt.%), F127 (at 0, 2.5 and 5 wt.%) and various loadings of Si-Ca-Na-Zn-Ce glass (at 20 and 40 wt.%) for incubation periods of up to 28 days. The concentration of each ion, at various time points, was determined using Inductively Coupled Plasma-Atomic Emission Spectrometry (Perkin Elmer Optima 3000). It was observed that the Si(4+), Na(+), Ca(2+), Zn(2+) release from CNGCs in this study ranged from 0.22 to 6.477 ppm, 2.307 to 3.277 ppm, 40 to 119 ppm, and 45 to 51 ppm, respectively. The Ce(4+) concentrations were under the minimum detection limits for the ICP instrument utilized. The results indicate that the ion release levels may be appropriate to mediate therapeutic effects with respect to peripheral nerve regeneration. The data generated in this paper provides requisite evidence to optimize composition for pre-clinical evaluation of the experimental composite. PMID:24364973

  18. The effect of platform switching on the levels of metal ion release from different implant–abutment couples

    PubMed Central

    Alrabeah, Ghada O; Knowles, Jonathan C; Petridis, Haralampos

    2016-01-01

    The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of metal ions released from platform-matched and platform-switched implant–abutment couples as a result of accelerated corrosion. Thirty-six titanium alloy (Ti-6Al-4V) and cobalt–chrome alloy abutments were coupled with titanium cylinders forming either platform-switched or platform-matched groups (n=6). In addition, 18 unconnected samples served as controls. The specimens were subjected to accelerated corrosion by static immersion in 1% lactic acid for 1 week. The amount of metal ions ion of each test tube was measured using inductively coupled plasma mass spectrometry. Scanning electron microscope (SEM) images and energy dispersive spectroscopy X-ray analyses were performed pre- and post-immersion to assess corrosion at the interface. The platform-matched groups demonstrated higher ion release for vanadium, aluminium, cobalt, chrome, and molybdenum compared with the platform-switched groups (P<0.05). Titanium was the highest element to be released regardless of abutment size or connection (P<0.05). SEM images showed pitting corrosion prominent on the outer borders of the implant and abutment platform surfaces. In conclusion, implant–abutment couples underwent an active corrosion process resulting in metal ions release into the surrounding environment. The highest amount of metal ions released was recorded for the platform-matched groups, suggesting that platform-switching concept has a positive effect in reducing the levels of metal ion release from the implant–abutment couples. PMID:27357323

  19. The effect of platform switching on the levels of metal ion release from different implant-abutment couples.

    PubMed

    Alrabeah, Ghada O; Knowles, Jonathan C; Petridis, Haralampos

    2016-01-01

    The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of metal ions released from platform-matched and platform-switched implant-abutment couples as a result of accelerated corrosion. Thirty-six titanium alloy (Ti-6Al-4V) and cobalt-chrome alloy abutments were coupled with titanium cylinders forming either platform-switched or platform-matched groups (n=6). In addition, 18 unconnected samples served as controls. The specimens were subjected to accelerated corrosion by static immersion in 1% lactic acid for 1 week. The amount of metal ions ion of each test tube was measured using inductively coupled plasma mass spectrometry. Scanning electron microscope (SEM) images and energy dispersive spectroscopy X-ray analyses were performed pre- and post-immersion to assess corrosion at the interface. The platform-matched groups demonstrated higher ion release for vanadium, aluminium, cobalt, chrome, and molybdenum compared with the platform-switched groups (P<0.05). Titanium was the highest element to be released regardless of abutment size or connection (P<0.05). SEM images showed pitting corrosion prominent on the outer borders of the implant and abutment platform surfaces. In conclusion, implant-abutment couples underwent an active corrosion process resulting in metal ions release into the surrounding environment. The highest amount of metal ions released was recorded for the platform-matched groups, suggesting that platform-switching concept has a positive effect in reducing the levels of metal ion release from the implant-abutment couples. PMID:27357323

  20. Cyclic silylated onium ions of group 15 elements.

    PubMed

    Reissmann, Matti; Schäfer, André; Panisch, Robin; Schmidtmann, Marc; Bolte, Michael; Müller, Thomas

    2015-03-01

    Five- and six-membered cyclic silylated onium ions of group 15 elements I were synthesized by intramolecular cyclization of transient silylium ions II. Silylium ions II were prepared by the hydride transfer reaction from silanes III using trityl cation as hydride acceptor. It was found that smaller ring systems could not be obtained by this approach. In these cases tritylphosphonium ions IV were isolated instead. Cations I and IV were isolated in the form of their tetrakispentafluorphenyl borates and characterized by multinuclear NMR spectroscopy and, in two cases, by X-ray diffraction analysis. Cyclic onium ions I showed no reactivity similar to that of isoelectronic intramolecular borane/phosphane frustrated Lewis pairs (FLPs). The results of DFT computations at the M05-2X level suggest that the strength of the newly formed Si-E linkage is the major reason for inertness of I[B(C6F5)4] versus molecular hydrogen. PMID:25664605

  1. In vitro cytotoxicity of metallic ions released from dental alloys.

    PubMed

    Milheiro, Ana; Nozaki, Kosuke; Kleverlaan, Cornelis J; Muris, Joris; Miura, Hiroyuki; Feilzer, Albert J

    2016-05-01

    The cytotoxicity of a dental alloy depends on, but is not limited to, the extent of its corrosion behavior. Individual ions may have effects on cell viability that are different from metals interacting within the alloy structure. We aimed to investigate the cytotoxicity of individual metal ions in concentrations similar to those reported to be released from Pd-based dental alloys on mouse fibroblast cells. Metal salts were used to prepare seven solutions (concentration range 100 ppm-1 ppb) of the transition metals, such as Ni(II), Pd(II), Cu(II), and Ag(I), and the metals, such as Ga(III), In(III), and Sn(II). Cytotoxicity on mouse fibroblasts L929 was evaluated using the MTT assay. Ni, Cu, and Ag are cytotoxic at 10 ppm, Pd and Ga at 100 ppm. Sn and In were not able to induce cytotoxicity at the tested concentrations. Transition metals were able to induce cytotoxic effects in concentrations similar to those reported to be released from Pd-based dental alloys. Ni, Cu, and Ag were the most cytotoxic followed by Pd and Ga; Sn and In were not cytotoxic. Cytotoxic reactions might be considered in the etiopathogenesis of clinically observed local adverse reactions. PMID:25549610

  2. Energy Release, Acceleration, and Escape of Solar Energetic Ions

    NASA Astrophysics Data System (ADS)

    de Nolfo, G. A.; Ireland, J.; Ryan, J. M.; Young, C. A.

    2013-12-01

    Solar flares are prodigious producers of energetic particles, and thus a rich laboratory for studying particle acceleration. The acceleration occurs through the release of magnetic energy, a significant fraction of which can go into the acceleration of particles. Coronal mass ejections (CMEs) certainly produce shocks that both accelerate particles and provide a mechanism for escape into the interplanetary medium (IP). What is less well understood is whether accelerated particles produced from the flare reconnection process escape, and if so, how these same particles are related to solar energetic particles (SEPs) detected in-situ. Energetic electron SEPs have been shown to be correlated with Type III radio bursts, hard X-ray emission, and EUV jets, making a very strong case for the connection between acceleration at the flare and escape along open magnetic field lines. Because there has not been a clear signature of ion escape, as is the case with the Type III radio emission for electrons, sorting out the avenues of escape for accelerated flare ions and the possible origin of the impulsive SEPs continues to be a major challenge. The key to building a clear picture of particle escape relies on the ability to map signatures of escape such as EUV jets at the Sun and to follow the progression of these escape signatures as they evolve in time. Furthermore, nuclear γ-ray emissions provide critical context relating ion acceleration to that of escape. With the advent observations from Fermi as well as RHESSI and the Solar Dynamics Observatory (SDO), the challenge of ion escape from the Sun can now be addressed. We present a preliminary study of the relationship of EUV jets with nuclear γ-ray emission and Type III radio observations and discuss the implications for possible magnetic topologies that allow for ion escape from deep inside the corona to the interplanetary medium.

  3. Trace element siting in iron sulfides from coal determined by secondary ion mass spectrometry

    SciTech Connect

    Wiese, R.G. Jr. ); Muir, I.J.; Fyfe, W.S. )

    1990-01-01

    Intact samples of coal have been analyzed by SIMS (secondary ion mass spectrometry) ion imaging and ion probe techniques for determination of the distribution of trace elements in pyrite and marcasite and in the associated clay minerals. Ion mapping of site-specific concentrations of trace elements is important as one considers the environmental consequences of not only the combustion of coal, but also the disposal of coal-washing plant refuse and the placement of mine spoils during reclamation. Iron sulfides and clays are both involved in the oxidation-hydration reactions that result in the formation of acid waters and the release of trace elements into the ecosystem. Iron sulfides from selected Ohio coals contain site-specific concentrations of Mn, Co, Ni, Cu, As, and Pb. Clay minerals found within and marginal to the sulfides contain V, Cr, and also As and Co. The distribution of trace elements in the sulfides and associated clays clearly is related to microenvironments that existed during the formation of successive parts of the sulfide grains. The sulfide-clay relationships determine the extent to which the sulfides break down in oxidation-hydration reactions.

  4. Molecular ion battery: a rechargeable system without using any elemental ions as a charge carrier

    PubMed Central

    Yao, Masaru; Sano, Hikaru; Ando, Hisanori; Kiyobayashi, Tetsu

    2015-01-01

    Is it possible to exceed the lithium redox potential in electrochemical systems? It seems impossible to exceed the lithium potential because the redox potential of the elemental lithium is the lowest among all the elements, which contributes to the high voltage characteristics of the widely used lithium ion battery. However, it should be possible when we use a molecule-based ion which is not reduced even at the lithium potential in principle. Here we propose a new model system using a molecular electrolyte salt with polymer-based active materials in order to verify whether a molecular ion species serves as a charge carrier. Although the potential of the negative-electrode is not yet lower than that of lithium at present, this study reveals that a molecular ion can work as a charge carrier in a battery and the system is certainly a molecular ion-based “rocking chair” type battery. PMID:26043147

  5. Molecular ion battery: a rechargeable system without using any elemental ions as a charge carrier

    NASA Astrophysics Data System (ADS)

    Yao, Masaru; Sano, Hikaru; Ando, Hisanori; Kiyobayashi, Tetsu

    2015-06-01

    Is it possible to exceed the lithium redox potential in electrochemical systems? It seems impossible to exceed the lithium potential because the redox potential of the elemental lithium is the lowest among all the elements, which contributes to the high voltage characteristics of the widely used lithium ion battery. However, it should be possible when we use a molecule-based ion which is not reduced even at the lithium potential in principle. Here we propose a new model system using a molecular electrolyte salt with polymer-based active materials in order to verify whether a molecular ion species serves as a charge carrier. Although the potential of the negative-electrode is not yet lower than that of lithium at present, this study reveals that a molecular ion can work as a charge carrier in a battery and the system is certainly a molecular ion-based “rocking chair” type battery.

  6. An evaluation of trace element release associated with acid mine drainage

    NASA Astrophysics Data System (ADS)

    Sullivan, Patrick J.; Yelton, Jennifer L.

    1988-12-01

    The determination of trace element release from geologic materials, such as oil shale and coal overburden, is important for proper solid waste management planning. The objective of this study was to determine a correlation between trace element residency and concentration to trace element release using the following methods: (1) sequential selective dissolution for determining trace element residencies, (2) toxicity characteristic leaching procedure (TCLP), and (3) humidity cell weathering study simulating maximum trace element release. Two eastern oil shales were used, a New albany shale that contains 4.6 percent pyrite, and a Chattanooga shale that contains 1.5 percent pyrite. Each shale was analyzed for elemental concentrations by soluble, adsorbed, organic, carbonate, and sulfide phases. All leachates were analyzed to determine total trace element concentrations. The results of the selective dissolution studies show that each trace element has a unique distribution between the various phases. Thus, it is possible to predict trace element release based on trace element residency. The TCLP results show that this method is suitable for assessing soluble trace element release but does not realistically assess potential hazards. The results of the humidity cell studies do demonstrate a more reasonable method for predicting trace element release and potential water quality hazards. The humidity cell methods, however, require months to obtain the required data with a large number of analytical measurements. When the selective dissolution data are compared to the trace element concentrations in the TCLP and humidity cell leachates, it is shown that leachate concentrations are predicted by the selective dissolution data. Therefore, selective dissolution may represent a rapid method to assess trace element release associated with acid mine drainage.

  7. Multi-element logic gates for trapped-ion qubits.

    PubMed

    Tan, T R; Gaebler, J P; Lin, Y; Wan, Y; Bowler, R; Leibfried, D; Wineland, D J

    2015-12-17

    Precision control over hybrid physical systems at the quantum level is important for the realization of many quantum-based technologies. In the field of quantum information processing (QIP) and quantum networking, various proposals discuss the possibility of hybrid architectures where specific tasks are delegated to the most suitable subsystem. For example, in quantum networks, it may be advantageous to transfer information from a subsystem that has good memory properties to another subsystem that is more efficient at transporting information between nodes in the network. For trapped ions, a hybrid system formed of different species introduces extra degrees of freedom that can be exploited to expand and refine the control of the system. Ions of different elements have previously been used in QIP experiments for sympathetic cooling, creation of entanglement through dissipation, and quantum non-demolition measurement of one species with another. Here we demonstrate an entangling quantum gate between ions of different elements which can serve as an important building block of QIP, quantum networking, precision spectroscopy, metrology, and quantum simulation. A geometric phase gate between a (9)Be(+) ion and a (25)Mg(+) ion is realized through an effective spin-spin interaction generated by state-dependent forces induced with laser beams. Combined with single-qubit gates and same-species entangling gates, this mixed-element entangling gate provides a complete set of gates over such a hybrid system for universal QIP. Using a sequence of such gates, we demonstrate a CNOT (controlled-NOT) gate and a SWAP gate. We further demonstrate the robustness of these gates against thermal excitation and show improved detection in quantum logic spectroscopy. We also observe a strong violation of a CHSH (Clauser-Horne-Shimony-Holt)-type Bell inequality on entangled states composed of different ion species. PMID:26672553

  8. Multi-element logic gates for trapped-ion qubits

    NASA Astrophysics Data System (ADS)

    Tan, T. R.; Gaebler, J. P.; Lin, Y.; Wan, Y.; Bowler, R.; Leibfried, D.; Wineland, D. J.

    2015-12-01

    Precision control over hybrid physical systems at the quantum level is important for the realization of many quantum-based technologies. In the field of quantum information processing (QIP) and quantum networking, various proposals discuss the possibility of hybrid architectures where specific tasks are delegated to the most suitable subsystem. For example, in quantum networks, it may be advantageous to transfer information from a subsystem that has good memory properties to another subsystem that is more efficient at transporting information between nodes in the network. For trapped ions, a hybrid system formed of different species introduces extra degrees of freedom that can be exploited to expand and refine the control of the system. Ions of different elements have previously been used in QIP experiments for sympathetic cooling, creation of entanglement through dissipation, and quantum non-demolition measurement of one species with another. Here we demonstrate an entangling quantum gate between ions of different elements which can serve as an important building block of QIP, quantum networking, precision spectroscopy, metrology, and quantum simulation. A geometric phase gate between a 9Be+ ion and a 25Mg+ ion is realized through an effective spin-spin interaction generated by state-dependent forces induced with laser beams. Combined with single-qubit gates and same-species entangling gates, this mixed-element entangling gate provides a complete set of gates over such a hybrid system for universal QIP. Using a sequence of such gates, we demonstrate a CNOT (controlled-NOT) gate and a SWAP gate. We further demonstrate the robustness of these gates against thermal excitation and show improved detection in quantum logic spectroscopy. We also observe a strong violation of a CHSH (Clauser-Horne-Shimony-Holt)-type Bell inequality on entangled states composed of different ion species.

  9. Angiogenesis in calcium phosphate scaffolds by inorganic copper ion release.

    PubMed

    Barralet, Jake; Gbureck, Uwe; Habibovic, Pamela; Vorndran, Elke; Gerard, Catherine; Doillon, Charles J

    2009-07-01

    Angiogenesis in a tissue-engineered device may be induced by incorporating growth factors (e.g., vascular endothelial growth factor [VEGF]), genetically modified cells, and=or vascular cells. It represents an important process during the formation and repair of tissue and is essential for nourishment and supply of reparative and immunological cells. Inorganic angiogenic factors, such as copper ions, are therefore of interest in the fields of regenerative medicine and tissue engineering due to their low cost, higher stability, and potentially greater safety compared with recombinant proteins or genetic engineering approaches. The purpose of this study was to compare tissue responses to 3D printed macroporous bioceramic scaffolds implanted in mice that had been loaded with either VEGF or copper sulfate. These factors were spatially localized at the end of a single macropore some 7 mm from the surface of the scaffold. Controls without angiogenic factors exhibited only poor tissue growth within the blocks; in contrast, low doses of copper sulfate led to the formation of microvessels oriented along the macropore axis. Further, wound tissue ingrowth was particularly sensitive to the quantity of copper sulfate and was enhanced at specific concentrations or in combination with VEGF. The potential to accelerate and guide angiogenesis and wound healing by copper ion release without the expense of inductive protein(s) is highly attractive in the area of tissue-engineered bone and offers significant future potential in the field of regenerative biomaterials. PMID:19182977

  10. Rocket having barium release system to create ion clouds in the upper atmosphere

    NASA Technical Reports Server (NTRS)

    Lewis, B. W.; Stokes, C. S.; Smith, E. W.; Murphy, W. J. (Inventor)

    1974-01-01

    A chemical system for releasing a good yield of free barium atoms and barium ions to create ion clouds in the upper atmosphere and interplanetary space for the study of the geophysical properties of the medium is presented.

  11. Stopping of energetic light ions in elemental matter

    NASA Astrophysics Data System (ADS)

    Ziegler, J. F.

    1999-02-01

    The formalism for calculating the stopping of energetic light ions (H, He, and Li) at energies above 1 MeV/u, has advanced to the point that stopping powers may now be calculated with an accuracy of a few percent for all elemental materials. Although the subject has been of interest for a century, only recently have the final required corrections been understood and evaluated. The theory of energetic ion stopping is reviewed with emphasis on those aspects that pertain to the calculation of accurate stopping powers.

  12. Electrodialytic separation of alkali-element ions with the aid of ion-exchange membranes

    SciTech Connect

    Gurskii, V.S.; Moskvin, L.N.

    1988-03-20

    Electrodialytic separation of ions bearing charges of the same sign with the aid of ion-exchange membranes has been examined in the literature in relation to the so-called ideal membranes, which do not exhibit selectivity with respect to one ion type in ion exchange. It has been shown that separation on such membranes is effective only for counterions differing in size of charge. A matter of greater importance from the practical standpoint is the possibility of using electrodialysis for separating ions bearing like charges and having similar properties, including ionic forms of isotopes of the same element. In this paper they report a comparative study of ion separation, with reference to the Cs-Na pair, by electrodialysis through various types of cation-exchange membranes. Changes of the solution concentration in the cathode compartment were monitored by measurement of /sup 22/Na and /sup 137/Cs activities.

  13. Influence of Finite Element Software on Energy Release Rates Computed Using the Virtual Crack Closure Technique

    NASA Technical Reports Server (NTRS)

    Krueger, Ronald; Goetze, Dirk; Ransom, Jonathon (Technical Monitor)

    2006-01-01

    Strain energy release rates were computed along straight delamination fronts of Double Cantilever Beam, End-Notched Flexure and Single Leg Bending specimens using the Virtual Crack Closure Technique (VCCT). Th e results were based on finite element analyses using ABAQUS# and ANSYS# and were calculated from the finite element results using the same post-processing routine to assure a consistent procedure. Mixed-mode strain energy release rates obtained from post-processing finite elem ent results were in good agreement for all element types used and all specimens modeled. Compared to previous studies, the models made of s olid twenty-node hexahedral elements and solid eight-node incompatible mode elements yielded excellent results. For both codes, models made of standard brick elements and elements with reduced integration did not correctly capture the distribution of the energy release rate acr oss the width of the specimens for the models chosen. The results suggested that element types with similar formulation yield matching results independent of the finite element software used. For comparison, m ixed-mode strain energy release rates were also calculated within ABAQUS#/Standard using the VCCT for ABAQUS# add on. For all specimens mod eled, mixed-mode strain energy release rates obtained from ABAQUS# finite element results using post-processing were almost identical to re sults calculated using the VCCT for ABAQUS# add on.

  14. Impact of Elevated CO2 on Trace Element Release from Aquifer Sediments of the San Joaquin Valley, CA

    NASA Astrophysics Data System (ADS)

    Fox, P. M.; Nico, P. S.; Davis, J. A.; Spycher, N.

    2014-12-01

    Carbon capture and storage (CCS) is a promising technique for mitigating climate change by storing large volumes of carbon dioxide in deep saline aquifers. In California, the thick marine sediments of the Central and Salinas Valleys have been identified as prime targets for future CO2 storage. However, the potential impacts on water quality of overlying drinking-water aquifers must be studied before CCS can be implemented. In this study, we compare trace element release from San Joaquin Valley aquifer sediments with a wide range of textural and redox properties. Kinetic batch experiments were performed with artificial groundwater continuously equilibrated under CO2-saturated (at 1 atm) and background CO2 (0.002-0.006 atm) conditions, resulting in a shift of nearly 3 pH units. In addition, the reversibility of trace element release was studied by sequentially lowering the CO2 from 1.0 atm to 0.5 atm to background concentrations (0.002-0.006 atm) for CO2-saturated systems in order to mimic the dissipation of a CO2 plume in the aquifer. During exposure to high CO2, a number of elements displayed enhanced release compared to background CO2 experiments (Ca, Mg, Li, Si, B, As, Sr, Ni, Fe, Mn, V, Ti, and Co) with concentrations of As, Fe, and Mn exceeding EPA maximum contaminant levels in some cases. On the other hand, Mo and U showed suppressed release. Most intriguing, many of the elements showing enhanced release displayed at least some degree of irreversibility when CO2 concentrations were decreased to background levels. In fact, in some cases (i.e., for V), an element showed further release when CO2 concentrations were decreased. These results suggest that there may be longer-term effects on groundwater quality that persist even after the CO2 plume has dissipated. Several different mechanisms of trace element release including ion exchange, desorption, and carbonate mineral dissolution are explored. Preliminary modeling results suggest that carbonate mineral

  15. Controls on Fe(II)-Activated Trace Element Release from Goethite and Hematite

    SciTech Connect

    Frierdich, Andrew J.; Catalano, Jeffrey G.

    2012-03-26

    Electron transfer and atom exchange (ETAE) between aqueous Fe(II) and Fe(III) oxides induces surface growth and dissolution that affects trace element fate and transport. We have recently demonstrated Ni(II) cycling through goethite and hematite (adsorbed Ni incorporates into the mineral structure and preincorporated Ni releases to solution) during Fe(II)-Fe(III) ETAE. However, the chemical parameters affecting net trace element release remain unknown. Here, we examine the chemical controls on Ni(II) and Zn(II) release from Ni- and Zn-substituted goethite and hematite during reaction with Fe(II). Release follows a rate law consistent with surface reaction limited mineral dissolution and suggests that release occurs near sites of Fe(III) reductive dissolution during Fe(II)-Fe(III) ETAE. Metal substituent type affects reactivity; Zn release is more pronounced from hematite than goethite, whereas the opposite trend occurs for Ni. Buildup of Ni or Zn in solution inhibits further release but this resumes upon fluid exchange, suggesting that sustained release is possible under flow conditions. Mineral and aqueous Fe(II) concentrations as well as pH strongly affect sorbed Fe(II) concentrations, which directly control the reaction rates and final metal concentrations. Our results demonstrate that structurally incorporated trace elements are mobilized from iron oxides into fluids without abiotic or microbial net iron reduction. Such release may affect micronutrient availability, contaminant transport, and the distribution of redox-inactive trace elements in natural and engineered systems.

  16. A parallel finite element simulator for ion transport through three-dimensional ion channel systems.

    PubMed

    Tu, Bin; Chen, Minxin; Xie, Yan; Zhang, Linbo; Eisenberg, Bob; Lu, Benzhuo

    2013-09-15

    A parallel finite element simulator, ichannel, is developed for ion transport through three-dimensional ion channel systems that consist of protein and membrane. The coordinates of heavy atoms of the protein are taken from the Protein Data Bank and the membrane is represented as a slab. The simulator contains two components: a parallel adaptive finite element solver for a set of Poisson-Nernst-Planck (PNP) equations that describe the electrodiffusion process of ion transport, and a mesh generation tool chain for ion channel systems, which is an essential component for the finite element computations. The finite element method has advantages in modeling irregular geometries and complex boundary conditions. We have built a tool chain to get the surface and volume mesh for ion channel systems, which consists of a set of mesh generation tools. The adaptive finite element solver in our simulator is implemented using the parallel adaptive finite element package Parallel Hierarchical Grid (PHG) developed by one of the authors, which provides the capability of doing large scale parallel computations with high parallel efficiency and the flexibility of choosing high order elements to achieve high order accuracy. The simulator is applied to a real transmembrane protein, the gramicidin A (gA) channel protein, to calculate the electrostatic potential, ion concentrations and I - V curve, with which both primitive and transformed PNP equations are studied and their numerical performances are compared. To further validate the method, we also apply the simulator to two other ion channel systems, the voltage dependent anion channel (VDAC) and α-Hemolysin (α-HL). The simulation results agree well with Brownian dynamics (BD) simulation results and experimental results. Moreover, because ionic finite size effects can be included in PNP model now, we also perform simulations using a size-modified PNP (SMPNP) model on VDAC and α-HL. It is shown that the size effects in SMPNP can

  17. Release of soluble elements from biochars derived from various biomass feedstocks.

    PubMed

    Wu, Hailu; Che, Xiaodong; Ding, Zhuhong; Hu, Xin; Creamer, Anne Elise; Chen, Hao; Gao, Bin

    2016-01-01

    Biochar as soil amendment can increase soil carbon (C) sequestration and mineral nutrients; however, some of its soluble elements may also be unintentionally released during the application. In this work, eight types of biochars were derived from herbaceous, woody, and waste (tailing, manure, sludge) biomass feedstocks through slow pyrolysis at 600 °C in N2. The elemental composition, specific surface area, morphology, crystalline phases, thermal stability, surface functional groups, and pH of the point of zero charge of the biochars were determined using various methods. These properties varied significantly among the tested biochars, suggesting that feedstock type played an important role in controlling their properties. Laboratory release and toxicity characteristic leaching procedure extraction experiments were conducted to evaluate the potential release of nutritious and toxic element from biochars. Results showed that all the biochars released nutritious elements and thus, may be beneficial to plants when amended in soils. In general, biochars produced from herbaceous and woody biomass feedstocks showed low risks of releasing toxic elements. Biochar derived from sludge, however, might present ecotoxicological challenges for its environmental applications due to the release of toxic elements, such as heavy metals. PMID:26408115

  18. Reactive-element effect studied using ion implantation

    SciTech Connect

    King, W.E.; Grabowski, K.S.

    1988-11-01

    Implantation of reactive elements into metals that form chromia layers upon exposure to high temperature oxidizing environments has a very large effect on the growth rate of the oxide and adhesion of the oxide to the base alloy. We have investigated the effect of Y ion implantation on the high temperature oxidation of Fe-24Cr using Rutherford backscattering spectroscopy, secondary ion mass spectroscopy, and electron microscopy. Analytical tools have been applied to determine the spatial distribution of Y, the microstructure of the oxide, and contribution of oxygen transport to the oxidation process. Results are compared with similar experiments in Fe-Cr alloys with Y additions and with results of cation and anion tracer diffusion experiments. 51 refs., 17 figs., 3 tabs.

  19. An experimental study on major element release from the sediments in the Changjiang (Yangtze River) Estuary

    NASA Astrophysics Data System (ADS)

    Guo, Yanwei; Yang, Shouye

    2015-06-01

    With the enhanced warming and acidification of global ocean, whether and to what extent the naturally-weathered fluvial sediment into the sea can release elements and thus influence the geochemical process and ecosystem of global ocean remain to be resolved. In this contribution, an experimental study was carried out to examine the release rates of major elements (Ca, K, Mg and Al) from the surface sediments in the Changjiang (Yangtze River) Estuary under the pH values of 4.0, 6.0 and 7.0. The two studied sediments consist primarily of quartz, plagioclase, calcite and clay minerals, with the BET (Brunauer, Emmett and Teller) surface areas of 61.7 m2 g-1 and 23.1 m2 g-1. Major elements of Ca, K, Mg and Al show different release rates under different solution pH values. With the decreasing solution pH, the release rates of Ca and K increase obviously, while the release rates of Mg and Al increase with the initial solution pH varying from 6.0 to 7.0. The different release rates of these elements are closely related to the original mineral composition of the sediments and the reaction kinetics. Based on the experimental observation, quartz and clay minerals that have low dissolution rates may dominate the major element release to the aqueous phase. This study reveals that the enhancing ocean acidification could cause considerable release of major elements from natural terrigenous sediments into the ambient marine environment, which has to be considered carefully in the future study on global change.

  20. Large areas elemental mapping by ion beam analysis techniques

    NASA Astrophysics Data System (ADS)

    Silva, T. F.; Rodrigues, C. L.; Curado, J. F.; Allegro, P.; Moro, M. V.; Campos, P. H. O. V.; Santos, S. B.; Kajiya, E. A. M.; Rizzutto, M. A.; Added, N.; Tabacniks, M. H.

    2015-07-01

    The external beam line of the Laboratory for Material Analysis with Ion Beams (LAMFI) is a versatile setup for multi-technique analysis. X-ray detectors for Particle Induced X-rays Emission (PIXE) measurements, a Gamma-ray detector for Particle Induced Gamma- ray Emission (PIGE), and a particle detector for scattering analysis, such as Rutherford Backscattering Spectrometry (RBS), were already installed. In this work, we present some results, using a large (60-cm range) XYZ computer controlled sample positioning system, completely developed and build in our laboratory. The XYZ stage was installed at the external beam line and its high spacial resolution (better than 5 μm over the full range) enables positioning the sample with high accuracy and high reproducibility. The combination of a sub-millimeter beam with the large range XYZ robotic stage is being used to produce elemental maps of large areas in samples like paintings, ceramics, stones, fossils, and all sort of samples. Due to its particular characteristics, this is a unique device in the sense of multi-technique analysis of large areas. With the continuous development of the external beam line at LAMFI, coupled to the robotic XYZ stage, it is becoming a robust and reliable option for regular analysis of trace elements (Z > 5) competing with the traditional in-vacuum ion-beam-analysis with the advantage of automatic rastering.

  1. Potentially toxic element release by fenton oxidation of sewage sludge.

    PubMed

    Andrews, J P; Asaadi, M; Clarke, B; Ouki, S

    2006-01-01

    The presence, in sewage sludge, of excess levels of the potentially toxic elements (PTE) copper, zinc, chromium, cadmium, nickel, lead and mercury, could impact on our ability to recycle these residues in the future. Far stricter limits on the levels of PTEs are likely in proposed legislation. A method involving the dosing of Fenton's reagent, a mixture of ferrous iron and hydrogen peroxide, under acidic conditions was evaluated for its potential to reduce metal levels. The [Fe]:[H2O2] (w/w) ratio was found to give a good indication of the percentage copper and zinc elution obtainable. Sites with no iron dosing as part of wastewater treatment required extra iron to be added in order to initiate the Fenton's reaction. A significant reduction, in excess of 70%, of the copper and zinc was eluted from both raw primary and activated sludge solid fractions. Cadmium and nickel could be reduced to below detection limits but elution of mercury, lead and chromium was less than 40%. The iron catalyst concentration was found to be a crucial parameter. This process has the potential to reduce the heavy metal content of the sludge and allow the recycling of sludge to continue in a sustainable manner. PMID:17087386

  2. Effect of liposome-albumin coatings on ferric ion retention and release from chitosan beads.

    PubMed

    Chandy, T; Sharma, C P

    1996-01-01

    Ferric chloride was embedded in a chitosan matrix to develop a prolonged-release form. The in vitro release profiles of ferric ions from chitosan beads were monitored in 0.1 M Tris-HCl buffer, pH 7.4, using a UV spectrophotometer. The amount of drug release was much higher initially, followed by a constant slow release profile for a prolonged period. The initial burst release was substantially modified with liposome and albumin coatings. From scanning electron microscope studies, it appears that the ferric ions diffuse out slowly to the dissolution medium through the micropores of the chitosan matrix. Further, the liposome forms a phospholipid membrane layer in the pores of chitosan beads and encapsulates the ferric ions within their vesicles and controls the release profile. The chitosan beads loaded with ferric ions substantially inhibited the polyurethane-associated calcification, in an in vitro model system. The released ferric ions, appeared to alter the protein-surface binding and improved the biocompatibility of the matrix. The results propose the possibility of modifying the polymer matrix to obtain a desired controlled release of the drug for a prolonged period. PMID:8962949

  3. Inductively coupled plasma mass spectrometer with laser ablation metal ions release detection in the human mouth

    NASA Astrophysics Data System (ADS)

    Kueerova, Hana; Dostalova, Tatjana; Prochazkova, J.

    2002-06-01

    Presence of more dental alloys in oral cavity often causes pathological symptoms. Due to various and multi-faced symptomatology, they tend to be a source of significant problems not only for the patient but also for the dentist. Metal ions released from alloys can cause subjective and objective symptoms in mouth. The aim of this study was detection of metal elements presence in saliva. There were 4 groups of examined persons: with intact teeth (15 individuals) with metallic restorations, pathological currents 5-30 (mu) A, multi-faced subjective symptomatology and uncharacteristic objective diagnosis (32 patients), with metallic restorations and no subjective symptoms (14 persons) and with metallic restorations, without pathological currents and with problems related to galvanism (13 patients). Presence of 14 metal elements was checked by inductively coupled plasma mass spectrometer with laser ablation. Nd:YAG laser detector was used. There were significant differences in content of silver, gold and mercury between persons with intact teeth and other three groups. There were no differences found between subjects with and without galvanic currents, and presence of subjective and objective symptoms.

  4. Radioactive Fission Product Release from Defective Light Water Reactor Fuel Elements

    SciTech Connect

    Konyashov, Vadim V.; Krasnov, Alexander M.

    2002-04-15

    Results are provided of the experimental investigation of radioactive fission product (RFP) release, i.e., krypton, xenon, and iodine radionuclides from fuel elements with initial defects during long-term (3 to 5 yr) irradiation under low linear power (5 to 12 kW/m) and during special experiments in the VK-50 vessel-type boiling water reactor.The calculation model for the RFP release from the fuel-to-cladding gap of the defective fuel element into coolant was developed. It takes into account the convective transport in the fuel-to-cladding gap and RFP sorption on the internal cladding surface and is in good agreement with the available experimental data. An approximate analytical solution of the transport equation is given. The calculation dependencies of the RFP release coefficients on the main parameters such as defect size, fuel-to-cladding gap, temperature of the internal cladding surface, and radioactive decay constant were analyzed.It is shown that the change of the RFP release from the fuel elements with the initial defects during long-term irradiation is, mainly, caused by fuel swelling followed by reduction of the fuel-to-cladding gap and the fuel temperature. The calculation model for the RFP release from defective fuel elements applicable to light water reactors (LWRs) was developed. It takes into account the change of the defective fuel element parameters during long-term irradiation. The calculation error according to the program does not exceed 30% over all the linear power change range of the LWR fuel elements (from 5 to 26 kW/m)

  5. Fragmentation of water by ion impact: Kinetic energy release spectra

    SciTech Connect

    Rajput, Jyoti; Safvan, C. P.

    2011-11-15

    The fragmentation of isolated water molecules on collision with 450-keV Ar{sup 9+} has been studied using time-of-flight mass spectrometry employing multihit detection. The kinetic energy release spectrum for the dissociation of [H{sub 2}O]{sup 2+ White-Star} into (H{sup White-Star },H{sup +},O{sup +}) fragments has been measured where H{sup White-Star} is a neutral Rydberg hydrogen atom. Ab initio calculations are carried out for the lowest states of [H{sub 2}O]{sup q+} with q=2 and 3 to help interpret the kinetic energy release spectra.

  6. On-demand release of corrosion-inhibiting ions from amorphous Al-Co-Ce alloys.

    PubMed

    Jakab, M A; Scully, J R

    2005-09-01

    Controlled release technologies are often used to supply chemicals or drugs at given rates. Release often occurs on contact with solution. However, some applications, such as corrosion protection, require containment of the active species in a reservoir and their slow release when needed. Conductive polymers have been used as reservoirs for corrosion inhibitors whose triggered release occurs by galvanic reduction or ion exchange. This work shows one of the first examples of pH-controlled release of corrosion-inhibiting ions from an amorphous metallic coating where the pH change that triggers release is a consequence of the onset of corrosion. This corrosion-inhibition strategy provides further corrosion protection beyond the traditional roles of barrier and sacrificial cathodic protection using a metal coating. For instance, zinc galvanizing provides sacrificial cathodic protection and acts as a barrier, but does not supply inhibitor ions. In the coating described here, protection of an underlying structural alloy exposed at coating defects is demonstrated by inhibitor ion release in addition to barrier function and sacrificial cathodic protection. PMID:16086020

  7. Cytotoxicity of Metal Ions Released from Nitinol Alloys on Endothelial Cells

    NASA Astrophysics Data System (ADS)

    Haider, W.; Munroe, N.; Tek, V.; Gill, P. K. S.; Tang, Y.; McGoron, A. J.

    2011-07-01

    Most implantable medical devices are expected to function in the body over an extended period of time. Therefore, immersion tests under simulated conditions can be useful for assessing the amount of metal ions released in situ. In this investigation, dissolved ions from as-received binary and ternary Nitinol alloys in cell culture media were periodically measured under static and dynamic conditions. Endothelial cells were grown in aliquots of culture media obtained and the effect of dissolved ions on cell proliferation and viability of endothelial cells (HUVEC) was studied by cytotoxicity assays. The concentration of metal ions in the media was measured by inductively coupled plasma mass spectrometry.

  8. An invitro analysis of elemental release and cytotoxicity of recast nickel-chromium dental casting alloys.

    PubMed

    Reddy, Nagam Raja; Abraham, Anandapandian Ponsekar; Murugesan, Krishnan; Matsa, Vasanthakumar

    2011-06-01

    Recasting of the casting alloys affects the composition and elemental release which may have cytotoxic effect different from the pure alloy in the surrounding tissues. An Invitro study was conducted to investigate the elemental release and their cytotoxic effects from commercially available Ni-Cr dental casting alloys, commonly used for fabricating fixed partial dentures. Three Ni-Cr alloys [Wiron 99(A), Ceramet (B), and Hi Nickel CB (C)] were tested. Alloy specimens (disks 3 × 5 mm) were casted and grouped as follows: Group I (A(1)/B(1)/C(1)): 100% pure alloy; Group II (A(2)/B(2)/C(2)): 50% new with 50% recast; and Group III (A(3)/B(3)/C(3)): 100% recast. Disks of each alloy type from each group were transferred to Dulbecco's modified eagle medium and left for 3 days at 37°C in an atmosphere of 5% CO(2). Ni, Cr, Co, Cu and Mo elemental release from metal alloys into culture medium was investigated using Inductively Coupled Plasma Mass Spectrometry. Cytotoxicity was tested using mouse fibroblast cells and MTT Assay. Controls consisted of 6 wells containing cells with no alloy specimens. Data were analyzed by two-way analysis of variance followed by t-test. The total amount of elements released in parts per billion for various casting groups were Group I, A(1)-6.572, B(1)-6.732, C(1)-8.407; Group II, A(2)-22.046, B(2)-26.450, C(2)-29.189; Group III, A(3)-84.554, B(3)-88.359, C(3)-92.264. More amounts of elements were released in Hi Nickel CB than Ceramet and Wiron 99 in all the three test groups. Percentage of viable cells from MTT analysis were Group I, A(1)-62.342, B(1)-61.322 C(1)-60.593, Group II, A(2)-58.699, B(2)-56.494, C(2)-52.688, Group III, A(3)-53.101, B(3)-52.195, C(3)-47.586. The viable cells present in the culture media were more in Wiron 99 than Ceramet and Hi Nickel CB. Elemental release increased with amount of recast alloy. Amongst the three alloys tested Hi Nickel CB had significantly higher elements released compared to Ceramet and Wiron 99

  9. Graphite corrosion and hydrogen release from HTR fuel elements in Q-brine

    SciTech Connect

    Fachinger, J.; Zhang, Z.X.; Brodda, B.G.

    1995-12-31

    Industrial reprocessing for High Temperature Reactors (HTR) fuel elements has never been installed in Germany. The spent fuel elements are being considered for final disposal in a rock salt repository in the deep geologic underground. Safety analysis requires the assumption of an accidental water ingress into the repository, resulting in the formation of a concentrated salt solution with the typical composition of a quinary brine. After corrosive penetration of the container walls, the brine may finally contact the fuel elements directly and mobilize radionuclides. Duve et al. investigated the leaching of the fission products and actinides from HTR fuel elements in Q-brine. The mobilization of {sup 14}C by graphite corrosion is one of the last data bases required as a source term for the release estimation of radionuclides in the final safety analysis. The evaluation of the hydrogen release was prescribed by the licensing board, because an excessive gas pressure may affect the overall integrity of the geological barrier. {sup 14}C occurs as dissolved organic and inorganic compounds in the brine. The leaching rate or organic {sup 14}C decreases from about 80 Bq to 1 Bq. The amount of organic {sup 14}C decreases from about 80 Bq to 1 Bq during leaching. The release of inorganic {sup 14}C ceases within 4 months. About 100 ppm of the total {sup 14}C inventory was released during leaching. Gaseous {sup 14}C has never been detected. The gas formation is based on the radiolytic degradation of water, with a formation rate of 0.04 to 0.11 ml/d. Gas chromatographic analysis of the gas proved that hydrogen is the main component of the released gas. Tritium and {sup 85}Kr were detected as traces with radio gas chromatography.

  10. Release Fractions from Multi-Element Spent Fuel Casks Resulting from HEDD Attack

    SciTech Connect

    Luna, R. E.

    2006-07-01

    This paper provides a simple model for estimating the release of respirable aerosols resulting from an attack on a spent fuel cask using a high energy density device (HEDD). Two primary experiments have provided data on potential releases from spent fuel casks under HEDD attack. Sandia National Laboratories (SNL) conducted the first in the early 1980's and the second was sponsored by Gessellshaft fur Anlagen- and Reaktorsicherheit (GRS) in Germany and conducted in France in 1994. Both used surrogate spent fuel assemblies in real casks. The SNL experiments used un-pressurized fuel pin assemblies in a single element cask while the GRS tests used pressurized fuel pin assemblies in a 9-element cask. Data from the two test programs is reasonably consistent, given the differences in the experiments, but the use of the test data for prediction of releases resulting from HEDD attack requires a method for accounting for the effects of pin pressurization release and the ratio of pin plenum gas release to cask free volume (VR). To account for the effects of VR and to link the two data sources, a simple model has been developed that uses both the SNL data and the GRS data as well as recent test data on aerosols produced in experiments with single pellets subjected to HEDD effects conducted under the aegis of the International Consortium's Working Group on Sabotage of Transport and Storage Casks (WGSTSC). (authors)

  11. Sustained insulin release with biodegradation of chitosan gel beads prepared by copper ions.

    PubMed

    Kofuji, Kyoko; Murata, Yoshifumi; Kawashima, Susumu

    2005-10-13

    Chitosan (CS) gel beads were prepared with chelated copper (II) ions as a vehicle for the delivery of peptide and protein drugs. Insulin, which is a model of peptide and protein drugs, was scarcely released from the CS gel beads in vitro, presumably due to the nature of interactions occurring between insulin, CS and the copper (II) ions. The efficacy of insulin released from the CS gel beads was confirmed by implantation into diabetic mice. A consistent reduction in blood glucose level was observed in vivo due to insulin release as the CS gel beads were degraded. Control over insulin release was achieved by altering the properties of the CS. Thus, CS gel beads are promising as a biocompatible and biodegradable vehicle by which peptide and protein drugs can be delivered. PMID:16139972

  12. PIXE and micro-PIXE studies of ion release around endosseous implants in animals

    NASA Astrophysics Data System (ADS)

    Egeni, G. P.; Jaksic, M.; Moschini, G.; Passi, P.; Piattelli, A.; Rossi, P.; Rudello, V.; Tauro, L.

    1996-04-01

    The so-called "osseointegration" of oral and orthopedic implants means that newly-formed bone embeds the alloplastic implant materials allowing long-term clinical success. Commercially pure smooth titanium, rough titanium (sand blasted or plasma spray coated), hydroxylapatite and other coatings present different patterns, especially in the early healing phase after surgery. PIXE and micro-PIXE analysis are to be considered effective techniques to measure ion diffusion at the implant-bone interface, and to evaluate the possible diffusion of metal into the organism. Investigations were carried out in rabbits, both with PIXE and micro-PIXE, to evaluate a possible release of titanium from implants into the tissues and to measure other elements at the bone-implant border. Preliminary results suggest that a minor diffusion of titanium exists, even if probably without any significant clinical disturbance. Indeed, there is some evidence of initial titanium accumulation in some organs after six months. A possible deposition of calcium and phosphorus on the metal might indicate a good biological behavior of titanium.

  13. Release of elements to natural water from sediments of Lake Roosevelt, Washington, USA

    USGS Publications Warehouse

    Paulson, Anthony J.; Cox, Stephen E.

    2007-01-01

    Reservoir sediments from Lake Roosevelt (WA, USA) that were contaminated with smelter waste discharged into the Columbia River (BC, Canada) were examined using three measures of elemental release reflecting varying degrees of physical mixing and time scales. Aqueous concentrations of Cd, Cu, Pb, and Zn in the interstitial water of reservoir sediments, in the gently stirred overlying waters of incubated sediment cores, and in supernatants of aggressively tumbled slurries of reservoir sediments generally were higher than the concentrations from a reference site. When compared to chronic water-quality criteria, all three measures of release suggest that slag-contaminated sediments near the U.S.-Canadian border are potentially toxic as a result of Cu release and Pb release in two of the three measures. All three measures of Cd release suggest potential toxicity for one site farther down the reservoir, probably contaminated as a result of transport and adsorption of Cd from smelter liquid waste. Releases of Zn and As did not appear to be potentially toxic. Carbonate geochemistry indirectly affects the potential toxicity by increasing water hardness.

  14. Niobium Uptake and Release by Bacterial Ferric Ion Binding Protein

    PubMed Central

    Shi, Yanbo; Harvey, Ian; Campopiano, Dominic; Sadler, Peter J.

    2010-01-01

    Ferric ion binding proteins (Fbps) transport FeIII across the periplasm and are vital for the virulence of many Gram negative bacteria. Iron(III) is tightly bound in a hinged binding cleft with octahedral coordination geometry involving binding to protein side chains (including tyrosinate residues) together with a synergistic anion such as phosphate. Niobium compounds are of interest for their potential biological activity, which has been little explored. We have studied the binding of cyclopentadienyl and nitrilotriacetato NbV complexes to the Fbp from Neisseria gonorrhoeae by UV-vis spectroscopy, chromatography, ICP-OES, mass spectrometry, and Nb K-edge X-ray absorption spectroscopy. These data suggest that NbV binds strongly to Fbp and that a dinuclear NbV centre can be readily accommodated in the interdomain binding cleft. The possibility of designing niobium-based antibiotics which block iron uptake by pathogenic bacteria is discussed. PMID:20445753

  15. Effect of calcium ions on the gelling and drug release characteristics of xanthan matrix tablets.

    PubMed

    Baumgartner, Sasa; Pavli, Matej; Kristl, Julijana

    2008-06-01

    Xanthan is a well-known biopolymer. It is an anionic polysaccharide, whose primary structure depends on the bacterial strain and fermentation conditions. Xanthan was extensively studied in combination with galactomannans, and over 90 patents cover the technology of this preparation. Our aim was to investigate the relation between the physical properties of a xanthan matrix in the absence or presence of calcium ions and its influence on the release of pentoxifylline. The release of pentoxifylline from xanthan tablets in purified water was shown to be very slow and governed by the process of polymer relaxation. The presence of calcium ions significantly increased the drug release, changing the release mechanism into a more diffusion controlled one. Xanthan matrices showed substantially faster and more extensive swelling in water than in the presence of Ca2+ ions. Surprisingly, negative correlation between drug release and degree of swelling was obtained for xanthan: the higher the swelling, the slower the drug release. Higher ionic strength led to lower erosion of xanthan tablets, and the gel layers formed were more rigid and of firmer texture, as shown by rheological experiments and textural profiling. The results indicate that the presence of Ca2+ ions in the solution or in matrices does not cause crosslinking of xanthan polymers, but causes charge screening of ionized groups on the trisaccharide side chains of xanthan, leading to lower inter-molecular repulsion and changing water arrangement. The understanding of the parameters influencing drug release leads to the conclusion that xanthan is suitable for controlled release formulations, especially with the incorporation of certain small counterions. PMID:18248802

  16. The Release of Trace Elements in the Process of Coal Coking

    PubMed Central

    Konieczyński, Jan; Zajusz-Zubek, Elwira; Jabłońska, Magdalena

    2012-01-01

    In order to assess the penetration of individual trace elements into the air through their release in the coal coking process, it is necessary to determine the loss of these elements by comparing their contents in the charge coal and in coke obtained. The present research covered four coke oven batteries differing in age, technology, and technical equipment. By using mercury analyzer MA-2 and the method of ICP MS As, Be, Cd, Co, Hg, Mn, Ni, Se, Sr, Tl, V, and Zn were determined in samples of charge coal and yielded coke. Basing on the analyses results, the release coefficients of selected elements were determined. Their values ranged from 0.5 to 94%. High volatility of cadmium, mercury, and thallium was confirmed. The tests have shown that although the results refer to the selected case studies, it may be concluded that the air purity is affected by controlled emission occurring when coke oven batteries are fired by crude coke oven gas. Fugitive emission of the trace elements investigated, occurring due to coke oven leaks and openings, is small and, is not a real threat to the environment except mercury. PMID:22666104

  17. Elemental mercury releases attributed to antiques--New York, 2000-2006.

    PubMed

    2007-06-15

    Metallic (i.e., elemental) mercury, a heavy, silvery odorless liquid, is in common household products such as thermostats and thermometers. Lesser-known household sources of elemental mercury include certain antique or vintage items such as clocks, barometers, mirrors, and lamps. Over time, the mercury in these items can leak, particularly as seals age or when the items are damaged, dropped, or moved improperly. Vacuuming a mercury spill or vaporization from spill-contaminated surfaces such as carpets, floors, furniture, mops, or brooms can increase levels of mercury in the air, especially in enclosed spaces. Environmental sampling conducted after releases of elemental mercury have indicated substantial air concentrations that were associated with increases in blood and urine mercury levels among exposed persons. In 1990, the Agency for Toxic Substances and Disease Registry (ATSDR) created the Hazardous Substances Emergency Events Surveillance (HSEES) system, a multistate health department surveillance system designed to help reduce morbidity and mortality associated with hazardous substance events. This report describes antique-related mercury releases reported to HSEES, all of which occurred in New York state during 2000-2006. Although none of these spills resulted in symptoms or acute health effects, they required remediation to prevent future mercury exposure. The findings underscore the need for caution when handling antiques containing elemental mercury and the need for proper remediation of spills. PMID:17568369

  18. The release of trace elements in the process of coal coking.

    PubMed

    Konieczyński, Jan; Zajusz-Zubek, Elwira; Jabłońska, Magdalena

    2012-01-01

    In order to assess the penetration of individual trace elements into the air through their release in the coal coking process, it is necessary to determine the loss of these elements by comparing their contents in the charge coal and in coke obtained. The present research covered four coke oven batteries differing in age, technology, and technical equipment. By using mercury analyzer MA-2 and the method of ICP MS As, Be, Cd, Co, Hg, Mn, Ni, Se, Sr, Tl, V, and Zn were determined in samples of charge coal and yielded coke. Basing on the analyses results, the release coefficients of selected elements were determined. Their values ranged from 0.5 to 94%. High volatility of cadmium, mercury, and thallium was confirmed. The tests have shown that although the results refer to the selected case studies, it may be concluded that the air purity is affected by controlled emission occurring when coke oven batteries are fired by crude coke oven gas. Fugitive emission of the trace elements investigated, occurring due to coke oven leaks and openings, is small and, is not a real threat to the environment except mercury. PMID:22666104

  19. Effects of Ion-Releasing Tooth-Coating Material on Demineralization of Bovine Tooth Enamel

    PubMed Central

    Kawasaki, Koji; Kambara, Masaki

    2014-01-01

    We compared the effect of a novel ion-releasing tooth-coating material that contained S-PRG (surface-reaction type prereacted glass-ionomer) filler to that of non-S-PRG filler and nail varnish on the demineralization of bovine enamel subsurface lesions. The demineralization process of bovine enamel was examined using quantitative light-induced fluorescence (QLF) and electron probe microanalyzer (EPMA) measurement. Ion concentrations in demineralizing solution were measured using inductively coupled plasma atomic (ICP) emission spectrometry and an ion electrode. The nail varnish group and the non-S-PRG filler group showed linear demineralization. Although the nail varnish group and the non-S-PRG filler group showed linear demineralization, the S-PRG filler group did not. Further, plane-scanning by EPMA analysis in the S-PRG filler group showed no changes in Ca ion distribution, and F ions showed peak levels on the surface of enamel specimens. Most ions in the demineralizing solution were present at higher concentrations in the S-PRG filler group than in the other two groups. In conclusion, only the S-PRG filler-containing tooth-coating material released ions and inhibited demineralization around the coating. PMID:24578706

  20. Antimicrobial Activity of Silver Ions Released from Zeolites Immobilized on Cellulose Nanofiber Mats.

    PubMed

    Rieger, Katrina A; Cho, Hong Je; Yeung, Hiu Fai; Fan, Wei; Schiffman, Jessica D

    2016-02-10

    In this study, we exploit the high silver ion exchange capability of Linde Type A (LTA) zeolites and present, for the first time, electrospun nanofiber mats decorated with in-house synthesized silver (Ag(+)) ion exchanged zeolites that function as molecular delivery vehicles. LTA-Large zeolites with a particle size of 6.0 μm were grown on the surface of the cellulose nanofiber mats, whereas LTA-Small zeolites (0.2 μm) and three-dimensionally ordered mesoporous-imprinted (LTA-Meso) zeolites (0.5 μm) were attached to the surface of the cellulose nanofiber mats postsynthesis. After the three zeolite/nanofiber mat assemblies were ion-exchanged with Ag(+) ions, their ion release profiles and ability to inactivate Escherichia coli (E. coli) K12 were evaluated as a function of time. LTA-Large zeolites immobilized on the nanofiber mats displayed more than an 11 times greater E. coli K12 inactivation than the Ag-LTA-Large zeolites that were not immobilized on the nanofiber mats. This study demonstrates that by decorating nanometer to micrometer scale Ag(+) ion-exchanged zeolites on the surface of high porosity, hydrophilic cellulose nanofiber mats, we can achieve a tunable release of Ag(+) ions that inactivate bacteria faster and are more practical to use in applications over powder zeolites. PMID:26788882

  1. Electron Beam Distruption due to Ion Release from Targets - Comparison Between Computer Calculations and Observations

    NASA Astrophysics Data System (ADS)

    Hughes, Thomas P.; Davis, Harold A.; Vermare, Christophe; Moir, David C.; Olson, Russell T.; Monty Wood, W.

    2001-10-01

    Experiments have been performed on the first axis of the DARHT electron beam accelerator to study the effects on the beam of ion emission from surfaces struck by electrons (see preceding abstract). Calculations using the two- and three-dimensional Lsp particle-in-cell code were performed to compare with experimental results. Two-dimensional calculations, which allow the release of ions when the impacted surface temperature increases by 300 deg C, accurately replicate the experimental results showing beam blow-up downstream of the surface just after ion emission. Three-dimensional calculations show the onset of a hose instability after beam blow up in agreement with observations. A comparison of calculations to identify the dominant ion species with direct ion measurements will be presented.

  2. Does Ion Release Differ Between Hip Resurfacing and Metal-on-metal THA?

    PubMed Central

    Moroni, Antonio; Cadossi, Matteo; Baldini, Nicola; Giannini, Sandro

    2008-01-01

    Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potential increased metal ion release. We hypothesized there were no differences in serum concentrations of chromium, cobalt, and molybdenum between patients who had metal-on-metal hip resurfacing (Group A; average head diameter, 48 mm; median followup, 24 months) and patients who had 28-mm metal-on-metal THA (Group B; median followup, 25 months). Serum concentrations also were compared with concentrations in healthy subjects. We identified no differences in ion levels between Groups A and B. A distinction was made according to gender. Women showed a higher chromium release in Group A whereas men had a higher cobalt release in Group B. Values obtained from Group A were higher than those of the control subjects. Our data suggest metal-on-metal bearings for THA should not be rejected because of concern regarding potential increased metal ion release; however, patients with elevated ion levels, even without loosening or toxicity, could be at higher risk and should be followed up periodically. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18196364

  3. Ion release and pH of a new endodontic cement, MTA and Portland cement

    PubMed Central

    Amini Ghazvini, Sara; Abdo Tabrizi, Maryam; Kobarfard, Farzad; Akbarzadeh Baghban, Alireza; Asgary, Saeed

    2009-01-01

    INTRODUCTION: This in vitro study measured and compared pH and phosphate and calcium ions release of a new endodontic material (CEM cement), mineral trioxide aggregate (MTA), and Portland cement (PC) using UV-visible technique, atomic absorption spectrophotometry methods, and pH meter, respectively. MATERIALS AND METHODS: Each material was placed in a plastic tube (n=10) and immersed in a glass flask containing deionized water. Half of the samples were tested for determining pH and released ions after 1h, 3h, 24h, 48h, 7d and 28d. Remaining samples (n=5), were evaluated after 28d. Data was analyzed using one way ANOVA and Tukey tests. RESULTS: Results indicated that all materials were highly alkaline and released calcium and low concentration of phosphate ions in all the time intervals. CEM cement released considerably higher concentration of phosphate during the first hour (P<0.05). CONCLUSION: This novel endodontic cement promoted alkaline pH in a similar manner to MTA and released calcium and phosphate. These conditions can stimulate the calcification process and explain the basic physico-chemical mechanisms of hard tissue regeneration of CEM cement. PMID:23940490

  4. Controlling ion release from bioactive glass foam scaffolds with antibacterial properties.

    PubMed

    Jones, Julian R; Ehrenfried, Lisa M; Saravanapavan, Priya; Hench, Larry L

    2006-11-01

    Bioactive glass scaffolds have been produced, which meet many of the criteria for an ideal scaffold for bone tissue engineering applications, by foaming sol-gel derived bioactive glasses. The scaffolds have a hierarchical pore structure that is very similar to that of cancellous bone. The degradation products of bioactive glasses have been found to stimulate the genes in osteoblasts. This effect has been found to be dose dependent. The addition of silver ions to bioactive glasses has also been investigated to produce glasses with bactericidal properties. This paper discusses how changes in the hierarchical pore structure affect the dissolution of the glass and therefore its bioactivity and rate of ion delivery and demonstrates that silver containing bioactive glass foam scaffolds can be synthesised. It was found that the rate of release of Si and Ca ions was more rapid for pore structures with a larger modal pore diameter, although the effect of tailoring the textural porosity on the rate of ion release was more pronounced. Bioactive glass scaffolds, containing 2 mol% silver, released silver ions at a rate that was similar to that which has previously been found to be bactericidal but not high enough to be cytotoxic to bone cells. PMID:17122909

  5. pH-dependent release of trace elements including platinum group elements (PGEs) from gasoline and diesel catalysts

    NASA Astrophysics Data System (ADS)

    Sucha, Veronika; Mihaljevic, Martin; Ettler, Vojtech; Strnad, Ladislav

    2014-05-01

    The release of trace metals and platinum group elements (PGEs) from automobile exhaust catalysts represents a remarkable source of higly dispersed environmental contamination. Especially, PGEs have shown increasing research interest due to their possible bioaccessibility. In our research, we focused on leaching behaviour of trace metals from gasoline and diesel automobile catalysts. While catalysts for gasoline engines contain a mixture of Pt-Pd-Rh or Pd-Rh, catalysts for diesel engines are composed only of Pt. We used dust from two crushed gasoline and two crushed diesel catalysts (new and aged). The dust of gasoline catalysts contains significant concentrations of Pt (700 mg.kg-1), Pd (11 000 mg.kg-1) and Rh (700 mg.kg-1). And the dust of diesel catalysts are composed of Pt (3 900 mg.kg-1) and they contains negligible amounts of Pd dan Rh (< 0.5 mg.kg-1, < 0.1 mg.kg-1, respectively). To evaluate leaching of trace metals from dust we used pH-stat leaching test according to the European standard CEN/TS 14997. The concentrations of cations: PGEs (Pt, Pd a Rh), K, Na, Ca, Mg, Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, La and Ce were determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS), and anions: F-, Cl-, SO42- and NO3- by high-performance liquid chromatography. Although the dusts from catalysts were relatively stable to acid/base influence, the leaching of trace metals from catalysts showed a dependence on pH. Generally, the highest concentrations were released under acidic conditions. The leaching of PGEs was higher for Pt in diesel catalysts and for Pd and Rh in gasoline catalysts. The highest concentrations of Zn and Pb were observed in old catalysts. The rare earth metals were released more from gasoline catalysts. Catalysts particles represent health risk especially with respect to their PGEs contents.

  6. Metal ion-induced toxic histamine release from human basophils and mast cells.

    PubMed

    Schedle, A; Samorapoompichit, P; Füreder, W; Rausch-Fan, X H; Franz, A; Sperr, W R; Sperr, W; Slavicek, R; Simak, S; Klepetko, W; Ellinger, A; Ghannadan, M; Baghestanian, M; Valent, P

    1998-03-15

    Recent data suggest that distinct metal ions can be released from dental alloys or other biomaterials, and may cause toxic effects on various cells. In this study, the effects of 14 metal ions on histamine release from human blood basophils (n = 4), isolated tissue mast cells (lung n = 8, uterus n = 2, skin n = 1, gingiva n = 1), the basophil cell line KU-812, and the mast cell line HMC-1 were analyzed. Of the 14 metal ions, Ag+ (0.33 mM) and Hg2+ (0.33 mM) were found to induce release of histamine in blood basophils, KU-812, mast cells, and HMC-1. The effects of Ag+ and Hg2+ were dose dependent and were observed within 60 min of incubation. In primary mast cells and basophils, AU3+ (0.33 mM) also induced histamine release, whereas no effects of Au3+ on HMC-1 or KU-812 cells were seen. The other metal ions showed no effects on primary or immortal cells within 60 min. However, Pt4+ (0.33 mM) induced histamine liberation in HMC-1 and lung mast cells after 12 h. The Ag+- and Hg2+-induced rapid release of histamine from HMC-1 was associated with ultrastructural signs of necrosis, but not apoptosis. In contrast, prolonged exposure to Pt4+ (0.33 mM, 14 h) induced apoptotic cell death in HMC-1 cells, as assessed by electron microscopy and DNA analysis. Together, certain metal ions induce distinct cytopathogenic effects in mast cells and basophils. Whereas Ag+, Hg2+, and Au3+ cause direct toxicity, Pt4 causes cell death through induction of apoptosis. Whether such effects contribute to local adverse reactions to metal-containing biomaterials in vivo remains to be determined. PMID:9492216

  7. Dynamic analysis of elemental mercury released from thermal decomposition of coal

    SciTech Connect

    Shaoqing Guo; Jianli Yang; Zhenyu Liu

    2009-09-15

    Mercury (Hg) is a toxic and ubiquitous trace element in coal. Monitoring its release behavior during coal processing is a challenging problem. This paper presents a method that is capable of online measurement of the dynamic release behavior of elemental Hg (Hg{sup 0}) from thermal decomposition of coal. The method couples a temperature-programmed decomposition unit with an atomic fluorescence spectrometry detector (TPD-AFS). The AFS signal can be converted to Hg content for quantitative analysis through calibration. The main advantage of the TPD-AFS system is that it can provide either real-time or accumulated data. It was confirmed that the amount of Hg{sup 0} determined by this method agreed well with that by the Ontario-Hydro method, and the results are reproducible with a high accuracy. The method can be used to characterize the release behavior of Hg in coals upon heating and may be used to identify the forms of occurrence of Hg in coals. 16 refs., 4 figs., 3 tabs.

  8. Intracellular accumulation of indium ions released from nanoparticles induces oxidative stress, proinflammatory response and DNA damage.

    PubMed

    Tabei, Yosuke; Sonoda, Akinari; Nakajima, Yoshihiro; Biju, Vasudevanpillai; Makita, Yoji; Yoshida, Yasukazu; Horie, Masanori

    2016-02-01

    Due to the widespread use of indium tin oxide (ITO), it is important to investigate its effect on human health. In this study, we evaluated the cellular effects of ITO nanoparticles (NPs), indium chloride (InCl3) and tin chloride (SnCl3) using human lung epithelial A549 cells. Transmission electron microscopy and inductively coupled plasma mass spectrometry were employed to study cellular ITO NP uptake. Interestingly, greater uptake of ITO NPs was observed, as compared with soluble salts. ITO NP species released could be divided into two types: 'indium release ITO' or 'tin release ITO'. We incubated A549 cells with indium release ITO, tin release ITO, InCl3 or SnCl2 and investigated oxidative stress, proinflammatory response, cytotoxicity and DNA damage. We found that intracellular reactive oxygen species were increased in cells incubated with indium release ITO, but not tin release ITO, InCl3 or SnCl2. Messenger RNA and protein levels of the inflammatory marker, interleukin-8, also increased following exposure to indium release ITO. Furthermore, the alkaline comet assay revealed that intracellular accumulation of indium ions induced DNA damage. Our results demonstrate that the accumulation of ionic indium, but not ionic tin, from ITO NPs in the intracellular matrix has extensive cellular effects. PMID:26378248

  9. Antibacterial activity and ion release of bonding agent containing amorphous calcium phosphate nanoparticles

    PubMed Central

    Chen, Chen; Weir, Michael D.; Cheng, Lei; Lin, Nancy; Lin-Gibson, Sheng; Chow, Laurence C.; Zhou, Xuedong; Xu, Hockin H. K.

    2015-01-01

    Objectives Recurrent caries at the margins is a primary reason for restoration failure. The objectives of this study were to develop bonding agent with the double benefits of antibacterial and remineralizing capabilities, to investigate the effects of NACP filler level and solution pH on Ca and P ion release from adhesive, and to examine the antibacterial and dentin bond properties. Methods Nanoparticles of amorphous calcium phosphate (NACP) and a quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM) were synthesized. Scotchbond Multi-Purpose (SBMP) primer and adhesive served as control. DMADDM was incorporated into primer and adhesive at 5% by mass. NACP was incorporated into adhesive at filler mass fractions of 10%, 20%, 30% and 40%. A dental plaque microcosm biofilm model was used to test the antibacterial bonding agents. Calcium (Ca) and phosphate (P) ion releases from the cured adhesive samples were measured vs. filler level and solution pH of 7, 5.5 and 4. Results Adding 5% DMADDM and 10–40% NACP into bonding agent, and water-aging for 28 days, did not affect dentin bond strength, compared to SBMP control at 1 day (p > 0.1). Adding DMADDM into bonding agent substantially decreased the biofilm metabolic activity and lactic acid production. Total microorganisms, total streptococci, and mutans streptococci were greatly reduced for bonding agents containing DMADDM. Increasing NACP filler level from 10% to 40% in adhesive increased the Ca and P ion release by an order of magnitude. Decreasing solution pH from 7 to 4 increased the ion release from adhesive by 6–10 folds. Significance Bonding agents containing antibacterial DMADDM and remineralizer NACP were formulated to have Ca and P ion release, which increased with NACP filler level from 10% to 40% in adhesive. NACP adhesive was “smart” and dramatically increased the ion release at cariogenic pH 4, when these ions would be most-needed to inhibit caries. Therefore, bonding agent

  10. Finite Element Analysis of Silicon Thin Films on Soft Substrates as Anodes for Lithium Ion Batteries

    NASA Astrophysics Data System (ADS)

    Shaffer, Joseph

    2011-12-01

    The wide-scale use of green technologies such as electric vehicles has been slowed due to insufficient means of storing enough portable energy. Therefore it is critical that efficient storage mediums be developed in order to transform abundant renewable energy into an on-demand source of power. Lithium (Li) ion batteries are seeing a stream of improvements as they are introduced into many consumer electronics, electric vehicles and aircraft, and medical devices. Li-ion batteries are well suited for portable applications because of their high energy-to-weight ratios, high energy densities, and reasonable life cycles. Current research into Li-ion batteries is focused on enhancing its energy density, and by changing the electrode materials, greater energy capacities can be realized. Silicon (Si) is a very attractive option because it has the highest known theoretical charge capacity. Current Si anodes, however, suffer from early capacity fading caused by pulverization from the stresses induced by large volumetric changes that occur during charging and discharging. An innovative system aimed at resolving this issue is being developed. This system incorporates a thin Si film bonded to an elastomeric substrate which is intended to provide the desired stress relief. Non-linear finite element simulations have shown that a significant amount of deformation can be accommodated until a critical threshold of Li concentration is reached; beyond which buckling is induced and a wavy structure appears. When compared to a similar system using rigid substrates where no buckling occurs, the stress is reduced by an order of magnitude, significantly prolonging the life of the Si anode. Thus the stress can be released at high Li-ion diffusion induced strains by buckling the Si thin film. Several aspects of this anode system have been analyzed including studying the effects of charge rate and thin film plasticity, and the results are compared with preliminary empirical measurements to

  11. Heavy Ion Inertial Fusion Energy: Summaries of Program Elements

    SciTech Connect

    Friedman, A; Barnard, J J; Kaganovich, I; Seidl, P A; Briggs, R J; Faltens, A; Kwan, J W; Lee, E P; Logan, B G

    2011-02-28

    The goal of the Heavy Ion Fusion (HIF) Program is to apply high-current accelerator technology to IFE power production. Ion beams of mass {approx}100 amu and kinetic energy {>=} 1 GeV provide efficient energy coupling into matter, and HIF enjoys R&D-supported favorable attributes of: (1) the driver, projected to be robust and efficient; see 'Heavy Ion Accelerator Drivers.'; (2) the targets, which span a continuum from full direct to full indirect drive (and perhaps fast ignition), and have metal exteriors that enable injection at {approx}10 Hz; see 'IFE Target Designs'; (3) the near-classical ion energy deposition in the targets; see 'Beam-Plasma Interactions'; (4) the magnetic final lens, robust against damage; see 'Final Optics-Heavy Ion Beams'; and (5) the fusion chamber, which may use neutronically-thick liquids; see 'Liquid-Wall Chambers.' Most studies of HIF power plants have assumed indirect drive and thick liquid wall protection, but other options are possible.

  12. Using support vector machines to improve elemental ion identification in macromolecular crystal structures

    SciTech Connect

    Morshed, Nader; Echols, Nathaniel; Adams, Paul D.

    2015-05-01

    A method to automatically identify possible elemental ions in X-ray crystal structures has been extended to use support vector machine (SVM) classifiers trained on selected structures in the PDB, with significantly improved sensitivity over manually encoded heuristics. In the process of macromolecular model building, crystallographers must examine electron density for isolated atoms and differentiate sites containing structured solvent molecules from those containing elemental ions. This task requires specific knowledge of metal-binding chemistry and scattering properties and is prone to error. A method has previously been described to identify ions based on manually chosen criteria for a number of elements. Here, the use of support vector machines (SVMs) to automatically classify isolated atoms as either solvent or one of various ions is described. Two data sets of protein crystal structures, one containing manually curated structures deposited with anomalous diffraction data and another with automatically filtered, high-resolution structures, were constructed. On the manually curated data set, an SVM classifier was able to distinguish calcium from manganese, zinc, iron and nickel, as well as all five of these ions from water molecules, with a high degree of accuracy. Additionally, SVMs trained on the automatically curated set of high-resolution structures were able to successfully classify most common elemental ions in an independent validation test set. This method is readily extensible to other elemental ions and can also be used in conjunction with previous methods based on a priori expectations of the chemical environment and X-ray scattering.

  13. INDUCTIVELY COUPLED ARGON PLASMA AS AN ION SOURCE FOR MASS SPECTROMETRIC DETERMINATION OF TRACE ELEMENTS

    EPA Science Inventory

    Solution aerosols are injected into an inductively coupled argon plasma (ICP) to generate a relatively high number density of positive ions derived from elemental constituents. A small fraction of these ions is extracted through a sampling orifice into a differentially pumped vac...

  14. FINAL REPORT. F-ELEMENT ION CHELATION IN HIGHLY BASIC MEDIA

    EPA Science Inventory

    A large body of data has been collected over the last fifty years on the chemical behaviorof f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueoussolutions that produce poorly understood oxide-hydroxide species; therefore, most of thefundament...

  15. Release of toxic Gd3+ ions to tumour cells by vitamin B12 bioconjugates.

    PubMed

    Siega, Patrizia; Wuerges, Jochen; Arena, Francesca; Gianolio, Eliana; Fedosov, Sergey N; Dreos, Renata; Geremia, Silvano; Aime, Silvio; Randaccio, Lucio

    2009-08-10

    Two probes consisting of vitamin B(12) (CNCbl) conjugated to Gd chelates by esterification of the ribose 5'-OH moiety, Gd-DTPA-CNCbl (1; DTPA = diethylenetriamine-N,N,N',N'',N''-pentaacetic acid) and Gd-TTHA-CNCbl (2; TTHA = triethylenetetramine-N,N,N',N'',N''',N'''-hexaacetic acid), have been synthesised and characterised. The crystal structure of a dimeric form of 1, obtained by crystallisation with an excess of GdCl(3), has been determined. The kinetics of binding to and dissociation from transcobalamin II show that 1 and 2 maintain high-affinity binding to the vitamin B(12) transport protein. Complex 2 is very stable with respect to Gd(3+) release owing to the saturated co-ordination of the Gd(3+) ion by four amino and five carboxylate groups. Hydrolysis of the ester functionality occurs on the time scale of several hours. The lack of saturation and the possible involvement of the ester functionality in co-ordination result in lower stability of 1 towards hydrolysis and in a considerable release of Gd(3+) in vitro. Gd(3+) ions released from 1 are avidly taken up by the K562 tumour cells to an extent corresponding to approximately 10(10) Gd(3+) per cell. The internalisation of toxic Gd(3+) ions causes a marked decrease in cell viability as assessed by Trypan blue and WST-1 tests. On the contrary, the experiments with the more stable 2 did not show any significant cell internalisation of Gd(3+) ions and any influence on cell viability. The results point to new avenues of in situ generation of cytotoxic pathways based on the release of toxic Gd(3+) ions by vitamin B(12) bioconjugates. PMID:19562781

  16. The effect of humic acids on the element release from high level waste glass

    SciTech Connect

    Wei, J.; Van Iseghem, P.

    1997-12-31

    Eu and Am doped glasses were interacted with synthetic interstitial clay water (SiC) and corresponding reference leachant, humic acids free interstitial solution (IS) to investigate the influence of humic acids on the leaching behavior of the waste glass. Static leach tests were carried out at 40 C and 90 C. The release of the lanthanide Eu and the actinide Am from the glass was obviously enhanced by the presence of humic acids. The leaching of transition elements, Fe and Ti strongly depends on the humic acids concentration. The leaching of glass matrix components, Al and B was also influenced by the concentrations of humic acids. However, humic acids have little effect on the leaching of glass matrix element Si.

  17. Nanoscale surface structuring during ion bombardment of elemental semiconductors

    NASA Astrophysics Data System (ADS)

    Anzenberg, Eitan

    2013-01-01

    Nano-patterning of surfaces with uniform ion bombardment yields a rich phase-space of topographic patterns. Particle irradiation can cause surface ultra-smoothing or self-organized nanoscale pattern formation in surface topography. Topographic pattern formation has previously been attributed to the effects of the removal of target atoms by sputter erosion. In this thesis, the surface morphology evolution of Si(100) and Ge(100) during low energy ion bombardment of Ar+ and Kr+ ions, respectively, is studied. Our facilities for studies of surface processes at the National Synchrotron Light Source (NSLS) allow in-situ characterization of surface morphology evolution during ion bombardment using grazing incidence small angle x-ray scattering (GISAXS). This technique is used to measure in reciprocal space the kinetics of formation or decay of correlated nanostructures on the surface, effectively measuring the height-height correlations. A linear model is used to characterize the early time kinetic behavior during ion bombardment as a function of ion beam incidence angle. The curvature coefficients predicted by the widely used erosive model of Bradley and Harper are quantitatively negligible and of the wrong sign when compared to the observed effect in both Si and Ge. A mass-redistribution model explains the observed ultra-smoothing at low angles, exhibits an instability at higher angles, and predicts the observed 45° critical angle separating these two regimes in Si. The Ge surface evolution during Kr+ irradiation is qualitatively similar to that observed for Ar+ irradiation of Si at the same ion energy. However, the critical angle for Ge cannot be quantitatively reproduced by the simple mass redistribution model. Crater function theory, as developed by Norris et al., incorporates both mass redistributive and erosive effects, and predicts constraining relationships between curvature coefficients. These constraints are compared to experimental data of both Si and Ge

  18. The Gypsy Database (GyDB) of mobile genetic elements: release 2.0.

    PubMed

    Llorens, Carlos; Futami, Ricardo; Covelli, Laura; Domínguez-Escribá, Laura; Viu, Jose M; Tamarit, Daniel; Aguilar-Rodríguez, Jose; Vicente-Ripolles, Miguel; Fuster, Gonzalo; Bernet, Guillermo P; Maumus, Florian; Munoz-Pomer, Alfonso; Sempere, Jose M; Latorre, Amparo; Moya, Andres

    2011-01-01

    This article introduces the second release of the Gypsy Database of Mobile Genetic Elements (GyDB 2.0): a research project devoted to the evolutionary dynamics of viruses and transposable elements based on their phylogenetic classification (per lineage and protein domain). The Gypsy Database (GyDB) is a long-term project that is continuously progressing, and that owing to the high molecular diversity of mobile elements requires to be completed in several stages. GyDB 2.0 has been powered with a wiki to allow other researchers participate in the project. The current database stage and scope are long terminal repeats (LTR) retroelements and relatives. GyDB 2.0 is an update based on the analysis of Ty3/Gypsy, Retroviridae, Ty1/Copia and Bel/Pao LTR retroelements and the Caulimoviridae pararetroviruses of plants. Among other features, in terms of the aforementioned topics, this update adds: (i) a variety of descriptions and reviews distributed in multiple web pages; (ii) protein-based phylogenies, where phylogenetic levels are assigned to distinct classified elements; (iii) a collection of multiple alignments, lineage-specific hidden Markov models and consensus sequences, called GyDB collection; (iv) updated RefSeq databases and BLAST and HMM servers to facilitate sequence characterization of new LTR retroelement and caulimovirus queries; and (v) a bibliographic server. GyDB 2.0 is available at http://gydb.org. PMID:21036865

  19. Computation of strain energy release rates for skin-stiffener debonds modeled with plate elements

    NASA Technical Reports Server (NTRS)

    Wang, J. T.; Raju, I. S.; Davila, C. G.; Sleight, D. W.

    1993-01-01

    An efficient method for predicting the strength of debonded composite skin-stiffener configurations is presented. This method, which is based on fracture mechanics, models the skin and the stiffener with two-dimensional (2D) plate elements instead of three-dimensional (3D) solid elements. The skin and stiffener flange nodes are tied together by two modeling techniques. In one technique, the corresponding flange and skin nodes are required to have identical translational and rotational degrees-of-freedom. In the other technique, the corresponding flange and skin nodes are only required to have identical translational degrees-of-freedom. Strain energy release rate formulas are proposed for both modeling techniques. These formulas are used for skin-stiffener debond cases with and without cylindrical bending deformations. The cylindrical bending results are compared with plane-strain finite element results. Excellent agreement between the two sets of results is obtained when the second technique is used. Thus, from these limited studies, a preferable modeling technique for skin-stiffener debond analysis using plate elements is established.

  20. The Gypsy Database (GyDB) of mobile genetic elements: release 2.0

    PubMed Central

    Llorens, Carlos; Futami, Ricardo; Covelli, Laura; Domínguez-Escribá, Laura; Viu, Jose M.; Tamarit, Daniel; Aguilar-Rodríguez, Jose; Vicente-Ripolles, Miguel; Fuster, Gonzalo; Bernet, Guillermo P.; Maumus, Florian; Munoz-Pomer, Alfonso; Sempere, Jose M.; Latorre, Amparo; Moya, Andres

    2011-01-01

    This article introduces the second release of the Gypsy Database of Mobile Genetic Elements (GyDB 2.0): a research project devoted to the evolutionary dynamics of viruses and transposable elements based on their phylogenetic classification (per lineage and protein domain). The Gypsy Database (GyDB) is a long-term project that is continuously progressing, and that owing to the high molecular diversity of mobile elements requires to be completed in several stages. GyDB 2.0 has been powered with a wiki to allow other researchers participate in the project. The current database stage and scope are long terminal repeats (LTR) retroelements and relatives. GyDB 2.0 is an update based on the analysis of Ty3/Gypsy, Retroviridae, Ty1/Copia and Bel/Pao LTR retroelements and the Caulimoviridae pararetroviruses of plants. Among other features, in terms of the aforementioned topics, this update adds: (i) a variety of descriptions and reviews distributed in multiple web pages; (ii) protein-based phylogenies, where phylogenetic levels are assigned to distinct classified elements; (iii) a collection of multiple alignments, lineage-specific hidden Markov models and consensus sequences, called GyDB collection; (iv) updated RefSeq databases and BLAST and HMM servers to facilitate sequence characterization of new LTR retroelement and caulimovirus queries; and (v) a bibliographic server. GyDB 2.0 is available at http://gydb.org. PMID:21036865

  1. Injection of metallic elements into an electron-beam ion trap using a Knudsen cell

    SciTech Connect

    Yamada, C.; Nagata, K.; Nakamura, N.; Ohtani, S.; Takahashi, S.; Tobiyama, T.; Tona, M.; Watanabe, H.; Yoshiyasu, N.; Sakurai, M.; Kavanagh, A. P.; Currell, F. J.

    2006-06-15

    A method of injecting metallic elements into an electron-beam ion trap (EBIT) is described. The method is advantageous over the conventional coaxial and pulsed injection methods in two ways: (a) complicated switching of injection and extraction beams can be avoided when extracting beams of highly charged ions from the EBIT and (b) a beam of stable intensity can be achieved. This method may be applicable to any metallic elements or metallic compounds that have vapor pressures of {approx}0.1 Pa at a temperature lower than 1900 deg. C. We have employed this method for the extraction of highly charged ions of Bi, Er, Fe, and Ho.

  2. Effect of simulated rainfall and weathering on release of preservative elements from CCA treated wood.

    PubMed

    Lebow, Stan; Williams, R Sam; Lebow, Patricia

    2003-09-15

    The release of arsenic from wood pressure-treated with chromated copper arsenate (CCA) can be decreased by application of wood finishes, but little is known about the types of finishes that are best suited for this purpose. This study evaluated the effects of finish water repellent content and ultraviolet (UV) radiation on the release of arsenic, copper, and chromium from CCA-treated wood exposed to simulated rainfall. Deck boards treated with CCA were either left unfinished or dipped in a finish prepared with 1%, 3%, or 5% water repellent. All specimens were exposed to leaching from simulated rainfall, and a subset of specimens was also exposed to UV radiation. The rainfall was collected and analyzed for total elemental arsenic, copper, and chromium. The water repellent significantly decreased the amounts of these elements in the runoff, but for the short duration of this study there was no difference among the three water repellent concentrations. It is possible that water repellent content would have a greater effect over a longer exposure period. Exposure to UV radiation caused a significant increase in leaching from both finished and unfinished specimens. This effect may be a result of increased surface area during weathering as well as loss of fibers caused by UV-induced surface erosion. PMID:14524438

  3. Ion release from, and fluoride recharge of a composite with a fluoride-containing bioactive glass

    PubMed Central

    Davis, Harry B.; Gwinner, Fernanda; Mitchell, John C.; Ferracane, Jack L.

    2014-01-01

    Objectives Materials that are capable of releasing ions such as calcium and fluoride, that are necessary for remineralization of dentin and enamel, have been the topic of intensive research for many years. The source of calcium has most often been some form of calcium phosphate, and that for fluoride has been one of several metal fluoride or hexafluorophosphate salts. Fluoride-containing bioactive glass (BAG) prepared by the sol-gel method acts as a single source of both calcium and fluoride ions in aqueous solutions. The objective of this investigation was to determine if BAG, when added to a composite formulation, can be used as a single source for calcium and fluoride ion release over an extended time period, and to determine if the BAG-containing composite can be recharged upon exposure to a solution of 5,000 ppm fluoride. Methods BAG 61 (61% Si; 31% Ca; 4% P; 3% F; 1% B) and BAG 81 (81% Si; 11% Ca; 4% P; 3% F; 1% B) were synthesized by the sol gel method. The composite used was composed of 50/50 Bis-GMA/TEGDMA, 0.8% EDMAB, 0.4% CQ, and 0.05% BHT, combined with a mixture of BAG (15%) and strontium glass (85%) to a total filler load of 72% by weight. Disks were prepared, allowed to age for 24 h, abraded, then placed into DI water. Calcium and fluoride release was measured by atomic absorption spectroscopy and fluoride ion selective electrode methods, respectively, after 2, 22, and 222 h. The composite samples were then soaked for 5 min in an aqueous 5,000 ppm fluoride solution, after which calcium and fluoride release was again measured at 2, 22, and 222 h time points. Results Prior to fluoride recharge, release of fluoride ions was similar for the BAG 61 and BAG 81 composites after 2 h, and also similar after 22 h. At the four subsequent time points, one prior to, and three following fluoride recharge, the BAG 81 composite released significantly more fluoride ions (p<0.05). Both composites were recharged by exposure to 5,000 ppm fluoride, although the BAG 81

  4. F-ELEMENT ION CHELATION IN HIGHLY BASIC MEDIA

    EPA Science Inventory

    The U.S. Department of Energy (DOE) is faced with the formidable task of developing techniques for the safe and cost effective remediation of 1.5 x 10 x 7ft 3 of high level waste (HLW) stored in the DOE complex. Only a small fraction of the waste contains radioactive elements, bu...

  5. Bone Cell–materials Interactions and Ni Ion Release of Anodized Equiatomic NiTi Alloy

    PubMed Central

    Bernard, Sheldon A.; Balla, Vamsi Krishna; Davies, Neal M.; Bose, Susmita; Bandyopadhyay, Amit

    2011-01-01

    Laser processed NiTi alloy was anodized for different durations in H2SO4 electrolyte with varying pH to create biocompatible surfaces with low Ni ion release as well as bioactive surfaces to enhance biocompatibility and bone cell-materials interactions. The anodized surfaces were assessed for their in vitro cell-materials interactions using human fetal osteoblast (hFOB) cells for 3, 7 and 11 days, and Ni ion release up to 8 weeks in simulated body fluids. The results were correlated with surface morphologies of anodized surfaces characterized using field-emission scanning electron microscopy (FESEM). The results show that the anodization creates a surface with nano/micro roughness depending on anodization conditions. The hydrophilicity of NiTi surface was found to improve after anodization due to lower contact angles in cell media, which dropped from 32° to < 5°. The improved wettability of anodized surfaces is further corroborated by their high surface energy comparable to that of cp Ti. Relatively high surface energy, especially polar component, and nano/micro surface features of anodized surfaces significantly increased the number of living cells and their adherence and growth on these surfaces. Finally, a significant drop in Ni ion release from 268 ± 11 to 136 ± 15 ppb was observed for NiTi surfaces after anodization. This work indicates that anodization of NiTi alloy has a positive influence on the surface energy and surface morphology, which in turn improve bone cell-materials interactions and reduce Ni ion release in vitro. PMID:21232641

  6. Speciation of hazardous elements released from glass-works fly ash into soils.

    NASA Astrophysics Data System (ADS)

    Udatný, M.; Mihaljevič, M.; Kochergina, Y.; Šebek, O.

    2012-04-01

    Keywords: Načetín, fly ash, lead, zinc, antimony, barium, soils, hazardous elements, contamination, BCR sequential extraction The release of hazardous elements from anomalous geomaterials represents risk for the environment. In our research, we focused on exogenic alteration of fly ash (FA) originating from glass-works in Svetla nad Sazavou (Czech Republic). This factory produces glass with high amounts of PbO. Fly ash from electrostatic filter contains elevated concentrations of Pb (800 ppm), Zn (13 500 ppm), Sb (31 500 ppm) and Ba (67 000 ppm). In present history, small amount of FA may be emitted from factory and can settle in the surrounding environment (soil). To assess possible risk for the environment we placed samples (0.5 g) of the FA in small nylon bags into soils with different vegetation cover (spruce, beech and unforested area) situated near village Načetín in the Krušné hory Mts. (Ore Mts.), northwest Czech Republic. This locality was selected as a representative example of contaminated place; it neighbours industrial cities and thermal power plants and this area was severally polluted in the past (several decades till early 1990s) mainly by sulphur compounds. The individual sites have the same geological background, climatic conditions and also the same pollution input levels. The distances between sites are about 500 meters. Bags with samples of the FA was placed into individual soil horizons (litter (A0), A, B and C horizons for spruce; litter (A0), A, B and C horizons for beech and A, B and C horizons for unforested area). The pH of all horizons did not exceed value 4.6 and the lowest pH values were observed in upper horizons. Samples of the FA were exposed in soils for a period of one year (October 2010 - October 2011), and then were removed together with samples of soils, which immediately surrounded the bags with the FA. Concentrations of studied elements in the FA and concentrations of these elements in the soil samples (initial and

  7. Enhancement of RIE: etched Diffractive Optical Elements surfaces by using Ion Beam Etching

    NASA Astrophysics Data System (ADS)

    Schmitt, J.; Bischoff, Ch.; Rädel, U.; Grau, M.; Wallrabe, U.; Völklein, F.

    2015-09-01

    Shaping of laser light intensities by using Diffractive Optical Elements allows the adaption of the incident light to its application. Fused silica is used where for example UV-light or high temperatures are mandatory. For high diffraction efficiency the quality of the etched surface areas is important. The investigation of different process parameters for Ion Beam and Reactive Ion Etching reveals that only Ion Beam Etching provides surfaces with optical quality. Measurements of the influence of the surface quality on the diffraction efficiencies prove that the surfaces generated by Reactive Ion Etching are not suitable. Due to the high selectivity of the process Reactive Ion Etching is nevertheless a reasonable choice for the fabrication of Diffractive Optical Elements. To improve the quality of the etched surfaces a post processing with Ion Beam Etching is developed. Simulations in MATLAB display that the angle dependent removal of the surface during the Ion Beam Etching causes a smoothing of the surface roughness. The positive influence of a post processing on the diffraction efficiency is outlined by measurements. The ion beam post processing leads to an increase of the etching depth. For the fabrication of high efficient Diffractive Optical Elements this has to be taken into account. The relation is investigated and transferred to the fabrication of four-level gratings. Diffraction efficiencies up to 78 % instead of the ideal 81 % underline the practicability of the developed post processing.

  8. [Leaching experiments on the release of trace elements from tailings of Chashan antimony mine, Guangxi, China].

    PubMed

    Cai, Yong-bing; Li, Ling; Wei, Xiao-fei; Zhang, Guo-ping; Li, Hai-xia; Fu, Zhi-ping

    2012-08-01

    The leaching of trace elements from tailings of an antimony mine in Guangxi Autonomous Region, China, was investigated through column leaching under wet-dry cycling and complete immersion conditions. Simulated acid rain (pH 4.0-4.4) and river water (pH 8.0) were used as the leaching solution. No matter the simulated acid rain or river water was used, the leachate always showed a slightly alkaline pH between 7.2 and 8.0, suggesting an acid neutralization capacity of the tailing. Compared to As and Pb, Sb was leached out to a much higher extent in this circumstance. Furthermore, Sb release was largely enhanced in wet-dry cycle compared to the complete immersion condition. In contrast, As was leached more readily in the complete immersion condition, and the longer the tailings were immersed in water, the higher the As concentration in the leachate. The leachate on day 5 and day 10 showed 1-2 times higher As concentration as compared with the leachate on day 1 and day 2. The leaching of Mn and Zn by simulated acid rain was much stronger than that by river water, and the release of Mn and Zn was more significantly affected by pH than by O2 (i.e., the difference between the wet-dry cycle and complete immersion condition). Sr showed a high release rate that was not affected by leaching solution or air-exposure condition. Basically, Pb showed a very low leaching potential. In general, an alkaline circumstance combined with wet-dry cycle forms the favorable condition for the release of Sb in the tailings. PMID:23213913

  9. Effect of ion irradiation on the properties multi-element plasma coatings

    NASA Astrophysics Data System (ADS)

    Eremin, E. N.; Syzdykova, A. S.; Guchenko, S. A.; Yurov, V. M.; Gyngazova, M. S.

    2016-02-01

    The paper presents the results of the study of ion irradiation on the properties of multi-element plasma coatings. The coatings were bombarded by argon ions using heavy current ion source with a hollow cathode. After ion irradiation, the structure and physical properties of the coatings change, however, the nature of the changes is different for different coatings. To predict the behavior of the coating exposed to irradiation is virtually impossible. Therefore, structural studies and investigation of physical properties of the coatings to determine their functional characteristics are to be conducted.

  10. Assessment of trace element impacts on agricultural use of water from the Dan River following the Eden coal ash release.

    PubMed

    Hesterberg, Dean; Polizzotto, Matthew L; Crozier, Carl; Austin, Robert E

    2016-04-01

    Catastrophic events require rapid, scientifically sound decision making to mitigate impacts on human welfare and the environment. The objective of this study was to analyze potential impacts of coal ash-derived trace elements on agriculture following a 35,000-tonne release of coal ash into the Dan River at the Duke Energy Steam Station in Eden, North Carolina. We performed scenario calculations to assess the potential for excessive trace element loading to soils via irrigation and flooding with Dan River water, uptake of trace elements by crops, and livestock consumption of trace elements via drinking water. Concentrations of 13 trace elements measured in Dan River water samples within 4 km of the release site declined sharply after the release and were equivalent within 5 d to measurements taken upriver. Mass-balance calculations based on estimates of soil trace-element concentrations and the nominal river water concentrations indicated that irrigation or flooding with 25 cm of Dan River water would increase soil concentrations of all trace elements by less than 0.5%. Calculations of potential increases of trace elements in corn grain and silage, fescue, and tobacco leaves suggested that As, Cr, Se, Sr, and V were elements of most concern. Concentrations of trace elements measured in river water following the ash release never exceeded adopted standards for livestock drinking water. Based on our analyses, we present guidelines for safe usage of Dan River water to diminish negative impacts of trace elements on soils and crop production. In general, the approach we describe here may serve as a basis for rapid assessment of environmental and agricultural risks associated with any similar types of releases that arise in the future. PMID:26033746

  11. Therapeutic ion-releasing bioactive glass ionomer cements with improved mechanical strength and radiopacity

    NASA Astrophysics Data System (ADS)

    Fuchs, Maximilian; Gentleman, Eileen; Shahid, Saroash; Hill, Robert; Brauer, Delia

    2015-10-01

    Bioactive glasses (BG) are used to regenerate bone, as they degrade and release therapeutic ions. Glass ionomer cements (GIC) are used in dentistry, can be delivered by injection and set in situ by a reaction between an acid-degradable glass and a polymeric acid. Our aim was to combine the advantages of BG and GIC, and we investigated the use of alkali-free BG (SiO2-CaO-CaF2-MgO) with 0 to 50% of calcium replaced by strontium, as the beneficial effects of strontium on bone formation are well documented. When mixing BG and poly(vinyl phosphonic-co-acrylic acid), ions were released fast (up to 90% within 15 minutes at pH 1), which resulted in GIC setting, as followed by infrared spectroscopy. GIC mixed well and set to hard cements (compressive strength up to 35 MPa), staying hard when in contact with aqueous solution. This is in contrast to GIC prepared with poly(acrylic acid), which were shown previously to become soft in contact with water. Strontium release from GIC increased linearly with strontium for calcium substitution, allowing for tailoring of strontium release depending on clinical requirements. Furthermore, strontium substitution increased GIC radiopacity. GIC passed ISO10993 cytotoxicity test, making them promising candidates for use as injectable bone cements.

  12. Using support vector machines to improve elemental ion identification in macromolecular crystal structures

    SciTech Connect

    Morshed, Nader; Echols, Nathaniel; Adams, Paul D.

    2015-04-25

    In the process of macromolecular model building, crystallographers must examine electron density for isolated atoms and differentiate sites containing structured solvent molecules from those containing elemental ions. This task requires specific knowledge of metal-binding chemistry and scattering properties and is prone to error. A method has previously been described to identify ions based on manually chosen criteria for a number of elements. Here, the use of support vector machines (SVMs) to automatically classify isolated atoms as either solvent or one of various ions is described. Two data sets of protein crystal structures, one containing manually curated structures deposited with anomalous diffraction data and another with automatically filtered, high-resolution structures, were constructed. On the manually curated data set, an SVM classifier was able to distinguish calcium from manganese, zinc, iron and nickel, as well as all five of these ions from water molecules, with a high degree of accuracy. Additionally, SVMs trained on the automatically curated set of high-resolution structures were able to successfully classify most common elemental ions in an independent validation test set. This method is readily extensible to other elemental ions and can also be used in conjunction with previous methods based on a priori expectations of the chemical environment and X-ray scattering.

  13. Using support vector machines to improve elemental ion identification in macromolecular crystal structures

    DOE PAGESBeta

    Morshed, Nader; Echols, Nathaniel; Adams, Paul D.

    2015-04-25

    In the process of macromolecular model building, crystallographers must examine electron density for isolated atoms and differentiate sites containing structured solvent molecules from those containing elemental ions. This task requires specific knowledge of metal-binding chemistry and scattering properties and is prone to error. A method has previously been described to identify ions based on manually chosen criteria for a number of elements. Here, the use of support vector machines (SVMs) to automatically classify isolated atoms as either solvent or one of various ions is described. Two data sets of protein crystal structures, one containing manually curated structures deposited with anomalousmore » diffraction data and another with automatically filtered, high-resolution structures, were constructed. On the manually curated data set, an SVM classifier was able to distinguish calcium from manganese, zinc, iron and nickel, as well as all five of these ions from water molecules, with a high degree of accuracy. Additionally, SVMs trained on the automatically curated set of high-resolution structures were able to successfully classify most common elemental ions in an independent validation test set. This method is readily extensible to other elemental ions and can also be used in conjunction with previous methods based on a priori expectations of the chemical environment and X-ray scattering.« less

  14. Using support vector machines to improve elemental ion identification in macromolecular crystal structures

    PubMed Central

    Morshed, Nader; Echols, Nathaniel; Adams, Paul D.

    2015-01-01

    In the process of macromolecular model building, crystallographers must examine electron density for isolated atoms and differentiate sites containing structured solvent molecules from those containing elemental ions. This task requires specific knowledge of metal-binding chemistry and scattering properties and is prone to error. A method has previously been described to identify ions based on manually chosen criteria for a number of elements. Here, the use of support vector machines (SVMs) to automatically classify isolated atoms as either solvent or one of various ions is described. Two data sets of protein crystal structures, one containing manually curated structures deposited with anomalous diffraction data and another with automatically filtered, high-resolution structures, were constructed. On the manually curated data set, an SVM classifier was able to distinguish calcium from manganese, zinc, iron and nickel, as well as all five of these ions from water molecules, with a high degree of accuracy. Additionally, SVMs trained on the automatically curated set of high-resolution structures were able to successfully classify most common elemental ions in an independent validation test set. This method is readily extensible to other elemental ions and can also be used in conjunction with previous methods based on a priori expectations of the chemical environment and X-ray scattering. PMID:25945580

  15. Real-time monitoring of inhibitory effects on glutamate-induced neurotransmitter release using a potassium ion image sensor

    NASA Astrophysics Data System (ADS)

    Kono, Akiteru; Sakurai, Takashi; Hattori, Toshiaki; Okumura, Koichi; Ishida, Makoto; Sawada, Kazuaki

    2015-02-01

    To directly image the release of neurotransmitters from neurons, we combined a substance-selective layer with a 128 × 128-pixel ion image sensor based on CMOS technology. Using the substance-specific image sensors, we studied the dynamics of potassium ion ( K+) release from neurons and examined the effect of ouabain on K+ release. K+ transients were significantly inhibited by ouabain. The K+ image sensor used in this study demonstrated the dynamic analysis of ligand-operated signal release and the pharmacological assessment of secretagogues without requiring cell labeling.

  16. Ions Release and pH of Calcium Hydroxide-, Chlorhexidine- and Bioactive Glass-Based Endodontic Medicaments.

    PubMed

    Carvalho, Ceci Nunes; Freire, Laila Gonzales; Carvalho, Alexandre Pinheiro Lima de; Duarte, Marco Antonio Húngaro; Bauer, José; Gavini, Giulio

    2016-01-01

    This study evaluated pH and release of calcium, sodium and phosphate ions from different medications in human dentin. Fifty premolars were prepared and randomly divided into groups: (CHX) - 2% chlorhexidine gel; (CHX + CH) - CHX + calcium hydroxide PA; (CH) - CH + propylene glycol 600; (NPBG) - experimental niobium phosphate bioactive glass + distilled water; (BG) - bioactive glass (Bio-Gran) + distilled water. The specimens were immersed in deionized water and the pH variations were measured. The quantification of ions in the solutions was made by inductively coupled plasma - atomic emission spectroscopy (ICP/AES) at 10 min, 24 h, 7, 14, 21 and 30 days. The results were analyzed by ANOVA and Tukey`s test, with a significance level of 5%. CH had the highest level of calcium ions release at 30 days, while CHX and BG released more sodium ions. BG, NPBG and CHX released a higher amount of phosphate ions. The pH of CH was significantly higher compared with the other groups. CH favored the greatest increase of pH and calcium ions release. The bioactive glasses released more sodium and phosphate ions and presented an alkaline pH immediately and after 30 days. PMID:27224568

  17. Effect of denture cleansers on metal ion release and surface roughness of denture base materials.

    PubMed

    Davi, Letícia Resende; Felipucci, Daniela Nair Borges; de Souza, Raphael Freitas; Bezzon, Osvaldo Luiz; Lovato-Silva, Cláudia Helena; Pagnano, Valéria Oliveira; Paranhos, Helena de Freitas Oliveira

    2012-01-01

    Chemical disinfectants are usually associated with mechanical methods to remove stains and reduce biofilm formation. This study evaluated the effect of disinfectants on release of metal ions and surface roughness of commercially pure titanium, metal alloys, and heat-polymerized acrylic resin, simulating 180 immersion trials. Disk-shaped specimens were fabricated with commercially pure titanium (Tritan), nickel-chromium-molybdenum-titanium (Vi-Star), nickel-chromium (Fit Cast-SB Plus), and nickel-chromium-beryllium (Fit Cast-V) alloys. Each cast disk was invested in the flasks, incorporating the metal disk to the heat-polymerized acrylic resin. The specimens (n=5) were immersed in these solutions: sodium hypochlorite 0.05%, Periogard, Cepacol, Corega Tabs, Medical Interporous, and Polident. Deionized water was used as a control. The quantitative analysis of metal ion release was performed using inductively coupled plasma mass spectrometry (ELAN DRC II). A surface analyzer (Surftest SJ-201P) was used to measure the surface roughness (µm). Data were recorded before and after the immersions and evaluated by two-way ANOVA and Tukey's test (α=0.05). The nickel release proved most significant with the Vi-Star and Fit Cast-V alloys after immersion in Medical Interporous. There was a significant difference in surface roughness of the resin (p=0.011) after immersion. Cepacol caused significantly higher resin roughness. The immersion products had no influence on metal roughness (p=0.388). It could be concluded that the tested alloys can be considered safe for removable denture fabrication, but disinfectant solutions as Cepacol and Medical Interporous tablet for daily denture immersion should be used with caution because it caused greater resin surface roughness and greater ion release, respectively. PMID:23207854

  18. BET bromodomain inhibition releases the Mediator complex from select cis-regulatory elements

    PubMed Central

    Bhagwat, Anand S.; Roe, Jae-Seok; Mok, Beverly A.; Hohmann, Anja F.; Shi, Junwei; Vakoc, Christopher R.

    2016-01-01

    The bromodomain and extraterminal (BET) protein BRD4 can physically interact with the Mediator complex, but the relevance of this association to the therapeutic effects of BET inhibitors in cancer is unclear. Here, we show that BET inhibition causes a rapid release of Mediator from a subset of cis-regulatory elements in the genome of acute myeloid leukemia (AML) cells. These sites of Mediator eviction were highly correlated with transcriptional suppression of neighboring genes, which are enriched for targets of the transcription factor MYB and for functions related to leukemogenesis. An shRNA screen of Mediator in AML cells identified the MED12, MED13, MED23, and MED24 subunits as performing a similar regulatory function to BRD4 in this context, including a shared role in sustaining a block in myeloid maturation. These findings suggest that the interaction between BRD4 and Mediator has functional importance for gene-specific transcriptional activation and for AML maintenance. PMID:27068464

  19. Metal ion release: also a concern for ceramic-on-ceramic couplings?

    PubMed

    Beraudi, Alina; Stea, Susanna; De Pasquale, Dalila; Bordini, Barbara; Catalani, Simona; Apostoli, Pietro; Toni, Aldo

    2014-01-01

    BIOLOX delta is the newest ceramic composite material of the BIOLOX family and its use in hip devices represents a good alternative to Metal-on-Metal or Metal-on-Polyethylene coupling. Some Metal-on-Metal hip devices have shown chromium and cobalt release, which promoted toxic effects. Furthermore, the ceramic composite contains trivalent chromium, even if strongly bound to the alumina lattice. The present study is aimed at detecting any 'in vivo' release of chromium ions from BIOLOX delta bearings in the blood, erythrocytes and urine of patients. Twenty patients implanted with total hip arthroplasty (THA) with BIOLOX delta-BIOLOX delta couplings and 21 subjects with no implanted prostheses were studied. Inductively coupled plasma mass spectrometry equipped with dynamic reaction cell was used for analysis. In the THA group the Cr ions values were; in blood mean 0.21 µg/l (±0.09), in serum 0.21 µg/l (±0.12), in normalized erythrocytes 0.13 µg/l (±0.09), in normalized urine 0.12 µg/g creatinine (±0.13). In the control group the Cr ions values were; in blood mean 0.22 µg/l (st dev 0.14), in serum 0.17 µg/l (±0.08), in normalized erythrocytes 0.13 µg/l (±0.11), in normalized urine 0.07 µg/g creatinine (±0.08). The Lab reference values were 0.1-5.0 µg/l for blood, 0.1-0.5 µg/l for serum, 0.14-4.58 µg/l for normalised erythrocytes and 0.05-2.2 µg/l for urine. All samples in both groups resulted in chromium levels within the normal reference range and the safety of BIOLOX delta ceramics, in terms of chromium ions release, has been demonstrated. PMID:24817392

  20. A zinc-sensing receptor triggers the release of intracellular Ca2+ and regulates ion transport

    PubMed Central

    Hershfinkel, Michal; Moran, Arie; Grossman, Nili; Sekler, Israel

    2001-01-01

    Changes in extracellular zinc concentration participate in modulating fundamental cellular processes such as proliferation, secretion, and ion transport in a mechanism that is not well understood. Here, we show that a micromolar concentration of extracellular zinc triggers a massive release of calcium from thapsigargin-sensitive intracellular pools in the colonocytic cell line HT29. Calcium release was blocked by a phospholipase-C inhibitor, indicating that formation of inositol 1,4,5-triphosphate is required for zinc-dependent calcium release. Zinc influx was not observed, indicating that extracellular zinc triggered the release. The Cai2+ release was zinc specific and could not be triggered by other heavy metals. Furthermore, zinc failed to activate the Ca2+-sensing receptor heterologously expressed in HEK293 cells. The zinc-induced Cai2+ rise stimulated the activity of the Na+/H+ exchanger in HT29 cells. Our results indicate that a previously uncharacterized extracellular, G protein-coupled, Zn2+-sensing receptor is functional in colonocytes. Because Cai2+ rise is known to regulate key cellular and signal-transduction processes, the zinc-sensing receptor may provide the missing link between extracellular zinc concentration changes and the regulation of cellular processes. PMID:11573009

  1. Ion energy distribution near a plasma meniscus with beam extraction for multi element focused ion beams

    SciTech Connect

    Mathew, Jose V.; Paul, Samit; Bhattacharjee, Sudeep

    2010-05-15

    An earlier study of the axial ion energy distribution in the extraction region (plasma meniscus) of a compact microwave plasma ion source showed that the axial ion energy spread near the meniscus is small ({approx}5 eV) and comparable to that of a liquid metal ion source, making it a promising candidate for focused ion beam (FIB) applications [J. V. Mathew and S. Bhattacharjee, J. Appl. Phys. 105, 96101 (2009)]. In the present work we have investigated the radial ion energy distribution (IED) under the influence of beam extraction. Initially a single Einzel lens system has been used for beam extraction with potentials up to -6 kV for obtaining parallel beams. In situ measurements of IED with extraction voltages upto -5 kV indicates that beam extraction has a weak influence on the energy spread ({+-}0.5 eV) which is of significance from the point of view of FIB applications. It is found that by reducing the geometrical acceptance angle at the ion energy analyzer probe, close to unidirectional distribution can be obtained with a spread that is smaller by at least 1 eV.

  2. Variations in elemental composition of several MEV/nucleon ions observed in interplanetary space

    NASA Technical Reports Server (NTRS)

    Mcguire, R. E.; Vonrosenvinge, T. T.; Reames, D. V.

    1985-01-01

    Six years of accumulated ISEE-3 and IMP-8 data to study variations in elemental relative abundances among the different populations of energetic ions seen in interplanetary space are surveyed. Evidence suggesting that heavy ion enrichments may be organized by a rigidity scaling factor A/Z over the range H to Fe is presented. Data to support the hypothesis that shock-associated particles are probably accelerated from ambient energetic fluxes are shown.

  3. Multi-spacecraft Observations of Heavy Ion Dropouts: Physical Processes, Fractionation Rates, and Release Mechanisms

    NASA Astrophysics Data System (ADS)

    Weberg, M. J.; Lepri, S. T.; Zurbuchen, T.

    2014-12-01

    Heavy ion dropouts in the solar wind are thought to originate from large, closed coronal loops. The distinctive, mass-dependent fractionation patterns of the dropouts requires that their source loops are relatively quiet and stable long enough (on the order of a day) to undergo gravitational settling. Therefore by studying the composition of heavy ion dropouts we are able to peer into the solar corona and glean information about the fine balance of physical processes. Additionally, the occurrence rates and magnetic profiles of dropouts suggest specific forms of magnetic reconnection are responsible for the release of the otherwise trapped plasma into the solar wind. In this study we identify and compare dropouts observed by two different satellites, ACE and Ulysses, which together provide over 20 years of continuous observations at a variety of heliographic latitudes and radii. The resulting partial global view (or 3D view) enables us to identify coronal source regions and release mechanisms of heavy ion dropouts. We also discuss a physical model of gravitational settling which can be used to reconcile fractionation rates with the rate at which plasma must be escaping via reconnection. Our conclusions and results may contribute towards the ongoing refinement and validation of theories which predict the origin of "slow type" solar wind.

  4. Enhanced Ag(+) Ion Release from Aqueous Nanosilver Suspensions by Absorption of Ambient CO2.

    PubMed

    Fujiwara, Kakeru; Sotiriou, Georgios A; Pratsinis, Sotiris E

    2015-05-19

    Nanosilver with closely controlled average particle diameter (7-30 nm) immobilized on nanosilica is prepared and characterized by X-ray diffraction, N2 adsorption, and transmission electron microscopy. The presence of Ag2O on the as-prepared nanosilver surface is confirmed by UV-vis spectroscopy and quantified by thermogravimetric analysis and mass spectrometry. The release of Ag(+) ions in deionized water is monitored electrochemically and traced quantitatively to the dissolution of a preexisting Ag2O monolayer on the nanosilver surface. During this dissolution, the pH of the host solution rapidly increases, suppressing dissolution of the remaining metallic Ag. When, however, a nanosilver suspension is exposed to a CO2-containing atmosphere, like ambient air during its storage or usage, then CO2 is absorbed by the host solution decreasing its pH and contributing to metallic Ag dissolution and further leaching of Ag(+) ions. So the release of Ag(+) ions from the above closely sized nanosilver solutions in the absence and presence of CO2 as well as under synthetic air containing 200-1800 ppm of CO2 is investigated along with the solution pH and related to the antibacterial activity of nanosilver. PMID:25923906

  5. Experimental study of trace element release during ultrahigh-pressure serpentinite dehydration

    NASA Astrophysics Data System (ADS)

    Spandler, Carl; Pettke, Thomas; Hermann, Joerg

    2014-04-01

    Subduction of serpentinite is envisaged to play a key role in volatile and element recycling at convergent plate margins, but there is currently little known about the composition of the fluid phase(s) released by devolatilisation of deeply subducted serpentinite. We have performed a series of ultrahigh pressure experiments to examine the phase relations and fluid compositions produced by reaction of a natural serpentinite under sub-arc conditions. We employ a novel technique of forming synthetic fluid inclusions in olivine at run conditions to preserve samples of experimental fluids for subsequent analysis. Our experiments confirm that the breakdown of antigorite and chlorite are the most important fluid-producing reactions from serpentinite at sub-arc depths. For our low CaO/Al2O3 peridotitic composition at 3.5 to 4.0 GPa we find that clinopyroxene reacts out below 750 °C and chlorite breaks down progressively between 700 and 800 °C to form garnet harzburgite. Raman analysis of synthetic fluid inclusions indicates that all experiments contained a single aqueous fluid phase, which - together with a lack of textural or mineralogical evidence for hydrous melting - indicates that the water-saturated solidus for our starting composition is above 900 °C at 4.0 GPa. Element concentrations in the fluid for three experiments were determined in situ via laser ablation ICP-MS of individual fluid inclusions. In general, the fluids are enriched in trace elements compared to the bulk starting material, but particularly so for Li, B, LILE, LREE, and U. Chlorite dehydration fluids have high Li/B, LREE/HREE and Ce/Y due to retention of some B in olivine, and retention of Y and HREE in garnet. Our results indicate that fluids produced by serpentinite dehydration at sub-arc depths may carry some of the slab-derived trace elements required for arc magmatism, and may fractionate key trace element ratios in the dehydrated residues, which in turn may ultimately contribute to the

  6. Nanofabrication of Optical Elements for SXR and EUV Applications: Ion Beam Lithography as a New Approach

    NASA Astrophysics Data System (ADS)

    Lenz, J.; Krupp, N.; Wilhein, T.; Irsen, S.

    2011-09-01

    Diffractive optical elements are important components for applications in soft x-ray and extreme ultraviolet radiation. At present, the standard fabrication method for such optics is based on electron beam lithography followed by nanostructuring. This requires a series of complex processes including exposure, reactive ion-etching, and electro-plating. We report on experiments showing the single-step fabrication of such elements using ion beam lithography. Both transmission and reflection gratings were fabricated and successfully implemented as spectrometers at laboratory soft x-ray sources. Additionally, first steps toward zone plate fabrication are described.

  7. Synergistic cytotoxic effects of ions released by zinc-aluminum bronze and the metallic salts on osteoblastic cells.

    PubMed

    Grillo, Claudia A; Morales, María L; Mirífico, María V; Fernández Lorenzo de Mele, Mónica A

    2013-07-01

    The use of copper-based alloys for fixed dental crowns and bridges is increasingly widespread in several countries. The aim of this work is to study the dissolution of a zinc-aluminum-bronze and the cytotoxic effects of the ions released on UMR-106 osteoblastic cell line. Two sources of ions were used: (1) ions released by the metal alloy immersed in the cell culture and (2) salts of the metal ions. Conventional electrochemical techniques, atomic absorption spectroscopy [to obtain the average concentration of ions (AC) in solution], and energy dispersive X-ray (EDX) spectroscopy analysis were used to study the corrosion process. Corrosion tests revealed a strong influence of the composition of the electrolyte medium and the immersion time on the electrochemical response. The cytotoxicity was evaluated with (a) individual ions, (b) combinations of two ions, and (c) the mixture of all the ions released by a metal disc of the alloy. Importantly, synergistic cytotoxic effects were found when Al-Zn ion combinations were used at concentration levels lower than the cytotoxic threshold values of the individual ions. Cytotoxic effects in cells in the vicinity of the metal disc were also found. These results were interpreted considering synergistic effects and a diffusion controlled mechanism that yields to concentration levels, in the metal surroundings, several times higher than the measured AC value. PMID:23596152

  8. Fluorescence effect of ion-implanted sapphire doped with Ag/Cu/Fe elements

    NASA Astrophysics Data System (ADS)

    Chen, Hua-jian; Wang, Yu-hua; Zhang, Xiao-jian; Dai, Hou-mei; Ji, Ling-ling; Wang, Ru-wu; Wang, Deng-jing; Lu, Jian-duo; Zheng, Li-rong

    2015-11-01

    The fluorescence effect and microstructure of the nanocomposite samples prepared by ion implantation have been studied in the subsurface area. Based on the UV-vis and VUV data, the luminescence properties of implanted samples have been presented and discussed. The research indicates that the surface plasma resonance has an impact on the fluorescence effect notably. In addition, the fluorescence performance of the substrates implanted with ions is related to the outermost electron number of the injection element. And SRIM is used to analyze the energy loss in the process of ion implantation.

  9. Influence of Surface Coating on Metal Ion Release: Evaluation in Patients With Metal Allergy.

    PubMed

    Thomas, Peter; Weik, Thomas; Roider, Gabriele; Summer, Burkhard; Thomsen, Marc

    2016-05-01

    Nickel, chromium, and cobalt in stainless steel and Cobalt-chrome-molybdenum (CoCrMo) alloys may induce allergy. The objectives of this study were to evaluate surface coating regarding ion release, patch test reactivity, and arthroplasty performance. Materials and methods included patch test in 31 patients with metal allergy and 30 patients with no allergy to stainless steel and CoCrMo disks that are uncoated or coated by titanium nitride/zirconium nitride (TiN/ZrN). Assessment include atomic absorption spectrometry of released nickel, cobalt, and chromium from the disks after exposure to distilled water, artificial sweat and culture medium. Results showed that both coatings reduced the nickel and chromium release from stainless steel and CoCrMo disks and mostly the cobalt release from the disks (maximally 11.755 µg/cm(2)/5 d to 1.624 by Ti-N and to 0.442 by ZrN). Six of the 31 patients with metal allergy reacted to uncoated disks, but none reacted to the coated disks. The current authors report on exemplary patients with metal allergy who had symptom relief by revision with surface-coated arthroplasty. The authors concluded that the surface coating may prevent cutaneous and peri-implant allergic reactions. [Orthopedics. 2016; 39(3):S24-S30.]. PMID:27219723

  10. Electrosynthesis and analytical characterization of PMMA coatings on titanium substrates as barriers against ion release.

    PubMed

    De Giglio, E; Cometa, S; Sabbatini, L; Zambonin, P G; Spoto, G

    2005-02-01

    The performance of polyacrylic coatings as barrier films against corrosion of titanium-based orthopaedic implants was investigated. In particular, poly(methyl methacrylate) (PMMA) was electrosynthesized on titanium substrates by electro-reductive processes from aqueous monomer solutions. The obtained PMMA coatings were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The effect of an annealing treatment on the morphology of coatings with respect to uniformity and porosity of films was assessed by scanning electron microscopy (SEM). An inductively coupled plasma-mass spectrometry (ICP-MS) technique was used for ion concentration measurements in ion release tests performed on TiAlV sheets modified with PMMA coatings (annealed and unannealed). Results indicated that the annealing process produces coatings with considerable anticorrosion performances. PMID:15657712

  11. Element synthesis calculations for stellar explosions: robust uncertainties, sensitivities, and radioactive ion beam measurements

    NASA Astrophysics Data System (ADS)

    Smith, Michael S.; Hix, W. Raphael; Parete-Koon, Suzanne; Dessieux, Luc; Ma, Zhanwen; Starrfield, Sumner; Bardayan, Daniel W.; Guidry, Michael W.; Smith, Donald L.; Blackmon, Jeffery C.; Mezzacappa, Anthony

    2004-12-01

    We utilize multiple-zone, post-processing element synthesis calculations to determine the impact of recent ORNL radioactive ion beam measurements on predictions of novae and X-ray burst simulations. We also assess the correlations between all relevant reaction rates and all synthesized isotopes, and translate nuclear reaction rate uncertainties into abundance prediction uncertainties, via a unique Monte Carlo technique.

  12. DETERMINATION OF ELEMENTAL COMPOSITIONS FROM MASS PEAK PROFILES OF THE MOLECULAR ION (M) AND THE M + 1 AND M + 2 IONS

    EPA Science Inventory

    The relative abundances of M + 1 and M + 2 ions help to identify the elemental composition of the molecular ion (M). But scan speed, snesitiity, and resolution limitations of mass spectrometers have impeded determination of these abundances. Mass peak profiling from selected ion ...

  13. The load and release characteristics on a strong cationic ion-exchange fiber: kinetics, thermodynamics, and influences

    PubMed Central

    Yuan, Jing; Gao, Yanan; Wang, Xinyu; Liu, Hongzhuo; Che, Xin; Xu, Lu; Yang, Yang; Wang, Qifang; Wang, Yan; Li, Sanming

    2014-01-01

    Ion-exchange fibers were different from conventional ion-exchange resins in their non-cross-linked structure. The exchange was located on the surface of the framework, and the transport resistance reduced significantly, which might mean that the exchange is controlled by an ionic reaction instead of diffusion. Therefore, this work aimed to investigate the load and release characteristics of five model drugs with the strong cationic ion-exchange fiber ZB-1. Drugs were loaded using a batch process and released in United States Pharmacopoeia (USP) dissolution apparatus 2. Opposing exchange kinetics, suitable for the special structure of the fiber, were developed for describing the exchange process with the help of thermodynamics, which illustrated that the load was controlled by an ionic reaction. The molecular weight was the most important factor to influence the drug load and release rate. Strong alkalinity and rings in the molecular structures made the affinity between the drug and fiber strong, while logP did not cause any profound differences. The drug–fiber complexes exhibited sustained release. Different kinds and concentrations of counter ions or different amounts of drug–fiber complexes in the release medium affected the release behavior, while the pH value was independent of it. The groundwork for in-depth exploration and further application of ion-exchange fibers has been laid. PMID:25114504

  14. Simulation studies of acceleration of heavy ions and their elemental compositions; IFSR--755

    SciTech Connect

    Toida, Mieko; Ohsawa, Yukiharu

    1996-07-01

    By using a one-dimensional, electromagnetic particle simulation code with full ion and electron dynamics, we have studied the acceleration of heavy ions by a nonlinear magnetosonic wave in a multi-ion-species plasma. First, we describe the mechanism of heavy ion acceleration by magnetosonic waves. We then investigate this by particle simulations. The simulation plasma contains four ion species: H, He, O, and Fe. The number density of He is taken to be 10% of that of H, and those of O and Fe are much lower. Simulations confirm that, as in a single-ion-species plasma, some of the hydrogens can be accelerated by the longitudinal electric field formed in the wave. Furthermore, they show that magnetosonic waves can accelerate all the particles of all the heavy species (He, O, and Fe) by a different mechanism, i.e., by the transverse electric field. The maximum speeds of the heavy species are about the same, of the order of the wave propagation speed. These are in good agreement with theoretical prediction. These results indicate that, if high-energy ions are produced in the solar corona through these mechanisms, the elemental compositions of these heavy ions can be similar to that of the background plasma, i.e., the corona.

  15. Electron Beam Distruption due to Ion Release from Targets - Experimental Observations

    NASA Astrophysics Data System (ADS)

    Vermare, Christophe; Davis, Harold A.; Hughes, Thomas P.; Moir, David C.; Olson, Russell; Wood, W. Monty

    2001-10-01

    A major concern for the new generation radiography facilities like DARHT and AIRIX is that ions or ionized neutrals released from solid surfaces by beam impact can be accelerated and trapped by the beam potential. This time-dependent positive-charge distribution, inside the beam channel, can disrupt the beam. Possible release mechanisms include electron induced desorption of neutrals or ions, thermal desorption due to beam-target heating, and melting or vaporization of the solid target. To study this, we have performed experiments on the DARHT first axis (1.7 kA, 20. MeV, 60 ns). Here, the beam, focused to a range of diameters, is transmitted through a thin target made of various materials. The time evolution of the beam radial profile is measured downstream of the target. For low current density, the downstream-beam radial profile is time invariant as expected. At higher current density, the downstream beam radial profile is clearly disrupted during the pulse including a large transverse instability.

  16. Exposure of Cleft Lip and Palate Patients to Toxic Elements Released during Orthodontic Treatment in the Study of Non-Invasive Matrices

    PubMed Central

    Mikulewicz, Marcin; Kachniarz, Krzysztof; Chojnacka, Katarzyna

    2015-01-01

    The Objective The aim of the study was evaluation of metal ions (nickel and chromium) released from orthodontic appliances in cleft lip and palate patients and the usefulness of non-invasive matrices (saliva and hair). Materials and Methods The material studied consisted of 100 individuals, including 59 females and 41 males of 5 to 16 years of age, which were divided into 3 groups: experimental–patients with cleft lip and palate (36 individuals, the average treatment time 5.74 years); control group–patients without cleft lip and palate, during orthodontic treatment (32 individuals, the average treatment time 1.78 years) and the control group patients without cleft lip and palate, without any orthodontic appliances (32 individuals). Samples (saliva, hair) were collected and subjects underwent a survey by questionnaire. Multi-elemental analyses of the composition of non-invasive matrices was conducted in an accredited laboratory by inductively coupled plasma spectrometry technique ICP-OES. The results were reported as mean contents of particular elements (Cd, Cr, Cu, Fe, Mn, Mo, Ni, Si) in hair and in saliva. Results The concentration of Cr, Ni, Fe and Cu ions in saliva of cleft lip and palate patients were several times higher as compared with not treated orthodontically control groups and higher than in the group with orthodontic appliances. Among the assessed matrices, hair of cleft lip and palate patients seem to be not a meaningful biomarker. Conclusion It was found that orthodontic appliances used in long-term treatment of cleft lip and palate patients do not release toxic levels of Cr and Ni ions. PMID:26544176

  17. Hydrocolloid-based nutraceutical delivery systems: Effect of counter-ions on the encapsulation and release

    PubMed Central

    Polowsky, Patrick J.; Janaswamy, Srinivas

    2014-01-01

    Nutraceuticals provide health benefits, especially for the prevention and treatment of chronic diseases such as diabetes, obesity, cardiovascular disease and cancer. Their incorporation in food supplements, functional foods and medicinal foods is a major technological challenge due to lower water solubility, instability during processing and storage conditions. Carriers that can effectively overcome these predicaments and protect them during product development, consumption and delivery are in high demand. Toward this end, our research approach is to entrap nutraceuticals in the ordered networks of hydrocolloids. We have examined the effect cations in regulating the encapsulated amounts and release characteristics. Iota-carrageenan and eugenol have been chosen as models of hydrocolloid and nutraceutical, respectively, in the presence of Na and Ca ions. The results suggest that carrageenan maintains its network organization even after encapsulating the eugenol molecules. Increased eugenol amounts are found in the Na carrageenan complex compared to the Ca complex, and the release rate is faster from the former but it is more controlled from the latter. These differences highlight the vital role of cations on the encapsulation efficiency and release profiles of hydrocolloid-based nutraceutical carriers. The outcome offers an elegant opportunity for developing novel and value-added food systems employing low-in-cost, nontoxic and heavily consumed food grade hydrocolloids. PMID:25419030

  18. Hydrocolloid-based nutraceutical delivery systems: Effect of counter-ions on the encapsulation and release.

    PubMed

    Polowsky, Patrick J; Janaswamy, Srinivas

    2015-01-01

    Nutraceuticals provide health benefits, especially for the prevention and treatment of chronic diseases such as diabetes, obesity, cardiovascular disease and cancer. Their incorporation in food supplements, functional foods and medicinal foods is a major technological challenge due to lower water solubility, instability during processing and storage conditions. Carriers that can effectively overcome these predicaments and protect them during product development, consumption and delivery are in high demand. Toward this end, our research approach is to entrap nutraceuticals in the ordered networks of hydrocolloids. We have examined the effect cations in regulating the encapsulated amounts and release characteristics. Iota-carrageenan and eugenol have been chosen as models of hydrocolloid and nutraceutical, respectively, in the presence of Na and Ca ions. The results suggest that carrageenan maintains its network organization even after encapsulating the eugenol molecules. Increased eugenol amounts are found in the Na carrageenan complex compared to the Ca complex, and the release rate is faster from the former but it is more controlled from the latter. These differences highlight the vital role of cations on the encapsulation efficiency and release profiles of hydrocolloid-based nutraceutical carriers. The outcome offers an elegant opportunity for developing novel and value-added food systems employing low-in-cost, nontoxic and heavily consumed food grade hydrocolloids. PMID:25419030

  19. Fabrication of porous zeolite/chitosan monoliths and their applications for drug release and metal ions adsorption.

    PubMed

    Zhang, Yongli; Yan, Weiwei; Sun, Zhiming; Pan, Cheng; Mi, Xue; Zhao, Gang; Gao, Jianping

    2015-03-01

    Ordered porous zeolite/chitosan (Zel/Chi) monoliths were prepared by a unidirectional freeze-drying method, and their properties and structures were characterized by various instrumental methods. The metal ion adsorption and the drug release performance of the porous Zel/Chi monoliths were also studied. The release rate of cefalexin from drug-loaded Zel/Chi monoliths depended on the composition and porous structure of the monoliths. The metal ion adsorption capacity of the Zel/Chi monoliths was related to the concentration of the metal ions, the adsorption time and the Zel/Chi ratio. An experimentally maximum adsorption of 89 mg/g was achieved for Cu(2+) ions. The Zel/Chi monoliths with adsorbed Cu(2+) ions effectively catalyzed the reduction of 4-nitrophenol to 4-aminophenol and had good recyclability. They were easily recovered by simply removing them from the reaction system and rinsing them with water. PMID:25498685

  20. Influence of drug distribution and solubility on release from geopolymer pellets--a finite element method study.

    PubMed

    Jämstorp, Erik; Strømme, Maria; Bredenberg, Susanne

    2012-05-01

    This study investigates the influence of drug solubility and distribution on its release from inert geopolymer pellets of three different sizes (1.5 × 1.5, 3 × 6, and 6 × 6 mm), having the same geopolymer composition and containing highly potent opioid fentanyl, sumatriptan, theophylline, or saccharin. Scanning electron microscopy, nitrogen sorption, drug solubility, permeation, and release experiments were performed, and estimates of the drug diffusion coefficients and solubilities in the geopolymer matrix were derived with the aid of finite element method (FEM). FEM was further employed to investigate the effect of a nonuniform drug distribution on the drug release profile. When inspecting the release profiles for each drug, it was observed that their solubilities in the geopolymer matrix imposed a much greater influence on the drug release rate than their diffusion coefficients. Concentrating the initial drug load in FEM into nonuniformly distributed drug regions inside the matrix created drug release profiles that more closely resembled experimental data than an FEM-simulated uniform drug distribution did. The presented FEM simulations and visualization of drug release from geopolymers under varying initial and dynamic conditions should open up for more systematic studies of additional factors that influence the drug release profile from porous delivery vehicles. PMID:22308066

  1. Ion-polycyclic aromatic hydrocarbon collisions: kinetic energy releases for specific fragmentation channels

    NASA Astrophysics Data System (ADS)

    Reitsma, G.; Zettergren, H.; Boschman, L.; Bodewits, E.; Hoekstra, R.; Schlathölter, T.

    2013-12-01

    We report on 30 keV He2 + collisions with naphthalene (C10H8) molecules, which leads to very extensive fragmentation. To unravel such complex fragmentation patterns, we designed and constructed an experimental setup, which allows for the determination of the full momentum vector by measuring charged collision products in coincidence in a recoil ion momentum spectrometer type of detection scheme. The determination of fragment kinetic energies is found to be considerably more accurate than for the case of mere coincidence time-of-flight spectrometers. In fission reactions involving two cationic fragments, typically kinetic energy releases of 2-3 eV are observed. The results are interpreted by means of density functional theory calculations of the reverse barriers. It is concluded that naphthalene fragmentation by collisions with keV ions clearly is much more violent than the corresponding photofragmentation with energetic photons. The ion-induced naphthalene fragmentation provides a feedstock of various small hydrocarbonic species of different charge states and kinetic energy, which could influence several molecule formation processes in the cold interstellar medium and facilitates growth of small hydrocarbon species on pre-existing polycyclic aromatic hydrocarbons.

  2. f-Element Ion Chelation in Highly Basic Media - Final Report

    SciTech Connect

    Paine, R.T.

    2000-12-12

    A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelator s for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

  3. Sensing Nature's Electric Fields: Ion Channels as Active Elements of Linear Amplification

    NASA Astrophysics Data System (ADS)

    Bezrukov, Sergey M.

    2003-05-01

    Given the parameters of familiar cellular elements — voltage-sensitive ion channels, carriers, pumps, phospholipid insulators, and electrolytic conductors — is it possible to construct an amplifier whose sensitivity matches the 5 nV/cm threshold found in behavioral experiments on elasmobranch fish? Or, in addition to clever circuitry that uses commonly known elements and principles, do we need something else to understand this sensitivity? The resolution of this question is important not only for studies in sensory biophysics seeking to reveal underlying mechanisms and molecular structures. More generally, it deepens our appreciation of the stochastic nature of inter- and intra-cellular control circuits. Here I analyze a simplified circuit involving negative differential resistance of voltage-sensitive ion channels. The analysis establishes an off-equilibrium criterion for amplification, shows that ion channels are the dominant noise sources, and, by minimizing channel noise within the given constraints, demonstrates that generic voltage-sensitive ion channels are likely candidates for the active elements of the linear cellular amplifiers. Finally, I highlight a number of unsolved issues.

  4. Metal ion-assisted self-assembly of complexes for controlled and sustained release of minocycline for biomedical applications

    PubMed Central

    Zhang, Zhiling; Wang, Zhicheng; Nong, Jia; Nix, Camilla A.; Ji, Hai-Feng; Zhong, Yinghui

    2015-01-01

    This study reports the development of novel drug delivery complexes self-assembled by divalent metal ion-assisted coacervation for controlled and sustained release of a hydrophilic small drug molecule minocycline (MH). MH is a multifaceted agent that has demonstrated therapeutic effects in infection, inflammation, tumor, as well as cardiovascular, renal, and neurological disorders due to its anti-microbial, anti-inflammatory, and cytoprotective properties. However, the inability to translate the high doses used in experimental animals to tolerable doses in human patients limits its clinical application. Localized delivery can potentially expose the diseased tissue to high concentrations of MH that systemic delivery cannot achieve, while minimizing the side effects from systemic exposure. The strong metal ion binding-assisted interaction enabled high drug entrapment and loading efficiency, and stable long term release for more than 71 days. Released MH demonstrated potent anti-biofilm, anti-inflammatory, and neuroprotective activities. Furthermore, MH release from the complexes is pH-sensitive as the chelation between minocycline and metal ions decreases with pH, allowing ‘smart’ drug release in response to the severity of pathology-induced tissue acidosis. This novel metal ion binding-mediated drug delivery mechanism can potentially be applied to other drugs that have high binding affinity for metal ions and may lead to the development of new delivery systems for a variety of drugs. PMID:25599696

  5. The release properties of silver ions from Ag-nHA/TiO2/PA66 antimicrobial composite scaffolds.

    PubMed

    Wu, Xia; Li, Jidong; Wang, Li; Huang, Di; Zuo, Yi; Li, Yubao

    2010-08-01

    Implant-associated bacterial infection can jeopardize the clinical success of implants and result in loss of supporting bone. The purpose of this study was to develop a novel porous scaffold with long-term antibacterial activity for bone repair or regeneration. Porous nano-hydroxyapatite/titania/polyamide66 scaffolds containing different amounts of silver ions (Ag-nHA/TiO(2)/PA66) were prepared by a phase inversion technique. The release of silver ions from the porous scaffolds in simulated body fluid (SBF) and in the F12 cell culture medium was evaluated via atomic absorption spectrometry. The results showed that the release of Ag(+) was time and concentration dependent, increasing with the immersion time and the silver content in the scaffolds. On the other hand, the release property of Ag(+) was also influenced by the immersion medium. The cumulative Ag(+) release in the F12 medium with time increase parabolically, different from the linear increase or the zero-order release kinetics in the SBF medium. Compared to the slight fluctuation of the Ag(+) release rate in SBF during the whole immersion period, the initial fast release rate and the later sustained release rate of Ag(+) in the F12 medium could be more helpful for preventing implant-associated infection. Since the Ag-nHA/TiO(2) particles were embedded in the PA66 matrix, the long-term-sustained release should be related both to the relaxation of PA macromolecular chains due to the penetration of water and to the slow release of the substituted Ag(+) ions in the HA lattice. The sustained Ag(+) release with time indicates that the composite scaffold is suitable for a long-term antimicrobial application during the scaffold-assisted bone repair or regeneration. PMID:20683127

  6. Fabricating high-density magnetic storage elements by low-dose ion beam irradiation

    SciTech Connect

    Neb, R.; Sebastian, T.; Pirro, P.; Hillebrands, B.; Pofahl, S.; Schaefer, R.; Reuscher, B.

    2012-09-10

    We fabricate magnetic storage elements by irradiating an antiferromagnetically coupled ferromagnetic/nonmagnetic/ferromagnetic trilayer by a low-dose ion beam. The irradiated areas become ferromagnetically coupled and are capable of storing information if their size is small enough. We employ Fe/Cr/Fe trilayers and a 30 keV focused Ga{sup +}-ion beam to demonstrate the working principle for a storage array with a bit density of 7 Gbit/in.{sup 2}. Micromagnetic simulations suggest that bit densities of at least two magnitudes of order larger should be possible.

  7. Nonlinear ion-acoustic waves in a degenerate plasma with nuclei of heavy elements

    SciTech Connect

    Hossen, M. A. Mamun, A. A.

    2015-10-15

    The ion-acoustic (IA) solitary waves propagating in a fully relativistic degenerate dense plasma (containing relativistic degenerate electron and ion fluids, and immobile nuclei of heavy elements) have been theoretically investigated. The relativistic hydrodynamic model is used to derive the Korteweg-de Vries (K-dV) equation by the reductive perturbation method. The stationary solitary wave solution of this K-dV equation is obtained to characterize the basic features of the IA solitary structures that are found to exist in such a degenerate plasma. It is found that the effects of electron dynamics, relativistic degeneracy of the plasma fluids, stationary nuclei of heavy elements, etc., significantly modify the basic properties of the IA solitary structures. The implications of this results in astrophysical compact objects like white dwarfs are briefly discussed.

  8. Nonlinear ion-acoustic waves in a degenerate plasma with nuclei of heavy elements

    NASA Astrophysics Data System (ADS)

    Hossen, M. A.; Mamun, A. A.

    2015-10-01

    The ion-acoustic (IA) solitary waves propagating in a fully relativistic degenerate dense plasma (containing relativistic degenerate electron and ion fluids, and immobile nuclei of heavy elements) have been theoretically investigated. The relativistic hydrodynamic model is used to derive the Korteweg-de Vries (K-dV) equation by the reductive perturbation method. The stationary solitary wave solution of this K-dV equation is obtained to characterize the basic features of the IA solitary structures that are found to exist in such a degenerate plasma. It is found that the effects of electron dynamics, relativistic degeneracy of the plasma fluids, stationary nuclei of heavy elements, etc., significantly modify the basic properties of the IA solitary structures. The implications of this results in astrophysical compact objects like white dwarfs are briefly discussed.

  9. Strain-energy-release rate analysis of the end-notched flexure specimen using the finite-element method

    NASA Technical Reports Server (NTRS)

    Salpekar, S. A.; Raju, I. S.; Obrien, T. K.

    1987-01-01

    Two-dimensional finite-element analysis of the end-notched flexure specimen was performed using 8-node isoparametric, parabolic elements to evaluate compliance and mode II strain energy release rates, G sub II. The G sub II values were computed using two different techniques: the virtural crack-closure technique (VCCT) and the rate of change of compliance with crack length (compliance derivative method). The analysis was performed for various crack-length-to-semi-span (a/L) ratios ranging from 0.2 to 0.9. Three material systems representing a wide range of material properties were analyzed. The compliance and strain energy release rates of the specimen calculated with the present finite-element analysis agree very well with beam theory equations including transverse shear. The G sub II values calculated using the compliance derivative method compared extremely well with those calculated using the VCCT. The G sub II values obtained by the compliance derivative method using the top or bottom beam deflections agreed closely with each other. The strain energy release rates from a plane-stress analysis were higher than the plane-strain values by only a small percentage, indicating that either assumption may be used in the analysis. The G sub II values for one material system calculated from the finite-element analysis agreed with one solution in the literature and disagreed with the other solution in the literature.

  10. Special diffractive elements for optical trapping fabricated on optical fiber tips using the focused ion beam

    NASA Astrophysics Data System (ADS)

    Rodrigues Ribeiro, R. S.; Guerreiro, A.; Viegas, J.; Jorge, P. A. S.

    2016-05-01

    In this work, spiral phase lenses and Fresnel zone lenses for beam tailoring, fabricated on the tip of optical fibers, are reported. The spiral phase lenses allow tailoring the fundamental guided mode, a Gaussian beam, into a Laguerre - Gaussian profile without using additional optical elements. Whereas, the Fresnel lenses are used as focusing systems. The lenses are fabricated using Focused Ion Beam milling, enabling high resolution in the manufacturing process. The output optical intensity profiles matching the numerical simulations are presented and analyzed.

  11. The Antimicrobial Properties of Silver Nanoparticles in Bacillus subtilis Are Mediated by Released Ag+ Ions

    PubMed Central

    Hsueh, Yi-Huang; Lin, Kuen-Song; Ke, Wan-Ju; Hsieh, Chien-Te; Chiang, Chao-Lung; Tzou, Dong-Ying; Liu, Shih-Tung

    2015-01-01

    The superior antimicrobial properties of silver nanoparticles (Ag NPs) are well-documented, but the exact mechanisms underlying Ag-NP microbial toxicity remain the subject of intense debate. Here, we show that Ag-NP concentrations as low as 10 ppm exert significant toxicity against Bacillus subtilis, a beneficial bacterium ubiquitous in the soil. Growth arrest and chromosomal DNA degradation were observed, and flow cytometric quantification of propidium iodide (PI) staining also revealed that Ag-NP concentrations of 25 ppm and above increased membrane permeability. RedoxSensor content analysis and Phag-GFP expression analysis further indicated that reductase activity and cytosolic protein expression decreased in B. subtilis cells treated with 10–50 ppm of Ag NPs. We conducted X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analyses to directly clarify the valence and fine structure of Ag atoms in B. subtilis cells placed in contact with Ag NPs. The results confirmed the Ag species in Ag NP-treated B. subtilis cells as Ag2O, indicating that Ag-NP toxicity is likely mediated by released Ag+ ions from Ag NPs, which penetrate bacterial cells and are subsequently oxidized intracellularly to Ag2O. These findings provide conclusive evidence for the role of Ag+ ions in Ag-NP microbial toxicity, and suggest that the impact of inappropriately disposed Ag NPs to soil and water ecosystems may warrant further investigation. PMID:26669836

  12. Mass analysis of neutral particles and ions released during electrical breakdowns on spacecraft surfaces

    NASA Technical Reports Server (NTRS)

    Kendall, B. R. F.

    1985-01-01

    Charged-particle fluxes from breakdown events were studied. Methods to measure mass spectra and total emitted flux of neutral particles were developed. The design and construction of the specialized mass spectrometer was completed. Electrical breakdowns were initiated by a movable blunt contact touching the insulating surface. The contact discharge apparatus was used for final development of two different high-speed recording systems and for measurements of the composition of the materials given off by the discharge. It was shown that intense instantaneous fluxes of neutral particles were released from the sites of electrical breakdown events. A laser micropulse mass analyzer showed that visible discoloration at breakdown sites were correllated with the presence of iron on the polymer side of the film, presumably caused by punch-through to the Inconel backing. Kapton samples irradiated by an oxygen ion beam were tested. The irradiated samples were free of surface hydrocarbon contamination but otherwise behaved in the same way as the Kapton samples tested earlier. Only the two samples exposed to oxygen ion bombardment were relatively clean. This indicates an additional variable that should be considered when testing spacecraft materials in the laboratory.

  13. Effect of hydroxyapatite thickness on metal ion release from Ti6Al4V substrates.

    PubMed

    Sousa, S R; Barbosa, M A

    1996-02-01

    The electrochemical dissolution behaviour of Ti6Al4V alloy coated with hydroxyapatite (HA) by plasma spraying was studied in Hank's balanced salt solution (HBSS) and compared with that of polished and grit-blasted passivated surfaces. Two different nominal thicknesses of HA (50 and 200 micro m) were used. Taking a polished passivated surface as reference, grit blasting of the substrate increased the electrical charge used in the oxidation of Ti6Al4V alloy at constant potential, as a result of increased surface area. However, only HA coatings with a thickness of 200 micro m were capable of reducing the charge to values lower than those measured for polished surfaces. Electrochemical impedance spectroscopy has also shown that only 200 micro m thick coatings are effective in reducing the oxidation rate of the substrate. Furthermore, in potentiostatic experiments the 50 micro m thick coating detached from the substrate, which did not occur with the 200 micro m thick coating. However, after 6 months immersion in HBSS, detachment occurred in some regions of both coatings. No titanium, aluminium or vanadium were detected in solution by electrothermal atomic absorption spectroscopy. These data indicate that HA is an effective barrier to metal ion release, even for the thinner coatings, due to formation of metal phosphates or to incorporation of metal ions in the HA structure. PMID:8938233

  14. Slow release of ions from internalized silver nanoparticles modifies the epidermal growth factor signaling response.

    PubMed

    Comfort, Kristen K; Maurer, Elizabeth I; Hussain, Saber M

    2014-11-01

    Due to their distinctive physiochemical properties, including a robust antibacterial activity and plasmonic capability, hundreds of consumer and medical products contain colloidal silver nanoparticles (AgNPs). However, even at sub-toxic dosages, AgNPs are able to disrupt cell functionality, through a yet unknown mechanism. Moreover, internalized AgNPs have the potential to prolong this disruption, even after the removal of excess particles. In the present study, we evaluated the impact, mechanism of action, and continual effects of 50 nm AgNP exposure on epidermal growth factor (EGF) signal transduction within a human keratinocyte (HaCaT) cell line. After AgNP expose, EGF signaling was initially obstructed due to the dissolution of particles into silver ions. However, at longer durations, the internalized AgNPs increased EGF signaling activity. This latter behavior correlated to sustained HaCaT stress, believed to be maintained through the continual dissolution of internalized AgNPs. This study raises concerns that even after exposure ceases, the retained nanomaterials are capable of acting as a slow-release mechanism for metallic ions; continually stressing and modifying normal cellular functionality. PMID:25260222

  15. EVALUATION OF TRACE ELEMENT RELEASE FROM FLUIDIZED-BED COMBUSTION SYSTEMS

    EPA Science Inventory

    The report gives results of an investigation of four trace elements: lead, beryllium, mercury, and fluorine. The chemical fate of minor and trace elements is important in assessing the environmental impact of the fluidized-bed combustion (FBC) process and, for certain elements, i...

  16. Nanometer scale elemental analysis in the helium ion microscope using time of flight spectrometry.

    PubMed

    Klingner, N; Heller, R; Hlawacek, G; von Borany, J; Notte, J; Huang, J; Facsko, S

    2016-03-01

    Time of flight backscattering spectrometry (ToF-BS) was successfully implemented in a helium ion microscope (HIM). Its integration introduces the ability to perform laterally resolved elemental analysis as well as elemental depth profiling on the nm scale. A lateral resolution of ≤54nm and a time resolution of Δt≤17ns(Δt/t≤5.4%) are achieved. By using the energy of the backscattered particles for contrast generation, we introduce a new imaging method to the HIM allowing direct elemental mapping as well as local spectrometry. In addition laterally resolved time of flight secondary ion mass spectrometry (ToF-SIMS) can be performed with the same setup. Time of flight is implemented by pulsing the primary ion beam. This is achieved in a cost effective and minimal invasive way that does not influence the high resolution capabilities of the microscope when operating in standard secondary electron (SE) imaging mode. This technique can thus be easily adapted to existing devices. The particular implementation of ToF-BS and ToF-SIMS techniques are described, results are presented and advantages, difficulties and limitations of this new techniques are discussed. PMID:26725148

  17. The Release of Elements from the Base Metal Alloys in a Protein Containing Biologic Environments and Artificial Saliva – An Invitro Study

    PubMed Central

    Shetty, Manoj; Prasad, D Krishna; Kanathila, Hema

    2016-01-01

    Introduction It has been reported that protein containing solutions can accelerate the release of elements from the base metal alloys. Aim This study aims to determine whether the solution in which an alloy is submerged and the exposure time have any effect on the amount of release of elements from the Ni-Cr and Co-Cr alloys. Material and Methods A total of 126 specimens were made from the Ni-Cr alloy and 42 specimens were made from Co-Cr alloy in the form of 5mm diameter discs, 2mm in thickness. Dissolution experiments were carried out in Bovine Serum Albumin (BSA) and artificial saliva for a period of seven weeks and atomic absorption spectrophotometer was used for elemental analysis. Statistical Analysis T-test was done to correlate the difference of elemental release from both BSA and artificial saliva. ANOVA test was done to compare the release at different time intervals and to compare the release of elements at different time intervals within a particular solution. TUKEY HSD test was done for comparison between the elements in a particular solution. Results The results showed that the elemental release was seen in both the solutions with a significant increase of release in BSA. The release of elements from the Ni-Cr alloy showed the predominant release of Cr. Conclusion The protein containing solution showed maximum release of elements from Ni-Cr and Co-Cr alloys. The elements that released from the alloys never reached their threshold for toxic effects. Hence these alloys can be safely used in fabrication of metal restorations without any ill effects. PMID:26894170

  18. Evaluation of calcium ion, hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments: An in vitro study

    PubMed Central

    Fulzele, Punit; Baliga, Sudhindra; Thosar, Nilima; Pradhan, Debaprya

    2011-01-01

    Aims: Evaluation of calcium ion and hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments. Objective: The purpose of this study was to evaluate calcium and hydroxyl ion release and pH levels of calcium hydroxide based products, namely, RC Cal, Metapex, calcium hydroxide with distilled water, along with the new gutta-percha points with calcium hydroxide. Materials and Methods: The materials were inserted in polyethylene tubes and immersed in deionized water. The pH variation, Ca++ and OH- release were monitored periodically for 1 week. Statistical Analysis Used: Statistical analysis was carried out using one-way analysis of variance and Tukey's post hoc tests with PASW Statistics version 18 software to compare the statistical difference. Results: After 1 week, calcium hydroxide with distilled water and RC Cal raised the pH to 12.7 and 11.8, respectively, while a small change was observed for Metapex, calcium hydroxide gutta-percha points. The calcium released after 1 week was 15.36 mg/dL from RC Cal, followed by 13.04, 1.296, 3.064 mg/dL from calcium hydroxide with sterile water, Metapex and calcium hydroxide gutta-percha points, respectively. Conclusions: Calcium hydroxide with sterile water and RC Cal pastes liberate significantly more calcium and hydroxyl ions and raise the pH higher than Metapex and calcium hydroxidegutta-percha points. PMID:22346155

  19. Garnet/high-silica rhyolite trace element partition coefficients measured by ion microprobe

    USGS Publications Warehouse

    Sisson, T.W.; Bacon, C.R.

    1992-01-01

    Garnet/liquid trace element partition coefficients have been measured in situ by ion microprobe in a rhyolite from Monache Mountain, California. Partition coefficients are reported for La, Ce, Nd, Sm, Dy, Er, Yb, Sc, Ti, V, Cr, Sr, Y, and Zr. The in situ analyses avoid the problem of contamination of the garnet phase by trace element-rich accessory minerals encountered in traditional bulk phenocryst/matrix partitioning studies. The partitioning pattern for the rare earth elements (REEs, excluding Eu) is smooth and rises steeply from the light to the heavy REEs with no sharp kinks or changes in slope, unlike patterns for garnet /silicic liquid REE partitioning determined by bulk methods. This difference suggests that the previous determinations by bulk methods are in error, having suffered from contamination of the phenocryst separates. ?? 1992.

  20. Unimolecular reactions of halogeno phenylarsenium ions: Kinetic energy release during the elimination of halogen hydride

    NASA Astrophysics Data System (ADS)

    Kirchhoff, Dirk; Grützmacher, Hans-Friedrich; Grützmacher, Hansjörg

    2006-03-01

    The four dihalogeno phenylarsanes C6H5AsF2, 1, C6H5AsCl2, 2, C6H5AsBr2, 3, and C6H5AsI2, 4, produce in the 70 eV-EI mass spectra by loss of a halogen atom abundant halogeno phenylarseniun ions C6H5As+-X, 1a+-4a+. The further fragmentation reactions of ions 1a+-4a+ are elimination of a molecule halogen hydride HX and/or loss of a halogen atom X. The preferred route of fragmentation depends clearly on the strength of the As-X bond. The metastable fluoro ion 1a+ and chloro ion 2a+, respectively, fragment only by loss of HF and HCl, the metastable bromo derivative 3a+ exhibits losses of HBr and Br of about equal intensity, and the metastable iodo ion 4a+ fragments only by loss of an I atom. The loss of HX is associated with a large kinetic energy release (KER) which yield a dish-topped peak in the MIKE spectrum of 1a+ ( = 845 meV) and 2a+ ( = 550 meV) and a broad round-topped peak on the MIKE spectrum of 3a+ ( = 369 meV). Theoretical calculations (UBHLYP/6-311 + G(2d,p)/-/UBHLYP/6-31 + G(d)) confirm that the elimination of HX requires an enthalpy of activation [Delta]H#, and that in the case of 3a+ this [Delta]H# and the reaction enthalpy for loss of Br are of similar size. The [Delta]H# of HX elimination is also responsible for the reverse enthalpy of activation and the KER during this process. The observed amounts to 78% (1a+), 55% (2a+), and 40% (3a+) of the calculated value of . Thus, the KER as well as the distribution of the KER (KERD) and the competition between elimination of HX and loss of X are very specific for the halogen ligand at the As atom. Metastable (4-fluorophenyl) arsenium ions 1b+, F-C6H4As+-H, and (4-chlorophenyl) arsenium ions 2b+, Cl-C6H4As+-H+, eliminate HF or HCl with virtually identical KERD as metastable 1a+ or 2a+, C6H5As+-Cl, proving an identical transition state for both isomers. Accordingly, 1b+ and 2b+ rearrange to 1a+ and 2a+ prior to HCl elimination. Such a rearrangement by a reductive elimination/oxidative insertion of

  1. Development and Evaluation of Sustained Release Tablet of Betahistine Hydrochloride Using Ion Exchange Resin Tulsion T344

    PubMed Central

    Wagh, Vijay D.; Pawar, Nilesh

    2012-01-01

    An attempt was made to sustain the release of Betahistine hydrochloride by complexation technique using strong cation-exchange resin, Tulsion T344. The drug loading onto ion-exchange resin was optimized for mixing time, activation, effect of pH, swelling time, ratio of drug : resin, and temperature. The resinate was evaluated for micromeritic properties and characterized using XRPD and IR. For resinate sustained release tablets were formulated using hydoxypropyl methylcellulose K100M. The tablets were evaluated for hardness, thickness, friability, drug content, weight variation, and in vitro drug release. Tablets thus formulated (Batch T-3) provided sustained release of drug over a period of 12 h. The release of Betahistine HCl from resinate controls the diffusion of drug molecules through the polymeric material into aqueous medium. Results showed that Betahistine HCl was formulated into a sustained dosage form as an alternative to the conventional tablet. PMID:22779010

  2. Development and evaluation of sustained release tablet of betahistine hydrochloride using ion exchange resin tulsion t344.

    PubMed

    Wagh, Vijay D; Pawar, Nilesh

    2012-01-01

    An attempt was made to sustain the release of Betahistine hydrochloride by complexation technique using strong cation-exchange resin, Tulsion T344. The drug loading onto ion-exchange resin was optimized for mixing time, activation, effect of pH, swelling time, ratio of drug : resin, and temperature. The resinate was evaluated for micromeritic properties and characterized using XRPD and IR. For resinate sustained release tablets were formulated using hydoxypropyl methylcellulose K100M. The tablets were evaluated for hardness, thickness, friability, drug content, weight variation, and in vitro drug release. Tablets thus formulated (Batch T-3) provided sustained release of drug over a period of 12 h. The release of Betahistine HCl from resinate controls the diffusion of drug molecules through the polymeric material into aqueous medium. Results showed that Betahistine HCl was formulated into a sustained dosage form as an alternative to the conventional tablet. PMID:22779010

  3. Stabilized finite element methods to simulate the conductances of ion channels

    NASA Astrophysics Data System (ADS)

    Tu, Bin; Xie, Yan; Zhang, Linbo; Lu, Benzhuo

    2015-03-01

    We have previously developed a finite element simulator, ichannel, to simulate ion transport through three-dimensional ion channel systems via solving the Poisson-Nernst-Planck equations (PNP) and Size-modified Poisson-Nernst-Planck equations (SMPNP), and succeeded in simulating some ion channel systems. However, the iterative solution between the coupled Poisson equation and the Nernst-Planck equations has difficulty converging for some large systems. One reason we found is that the NP equations are advection-dominated diffusion equations, which causes troubles in the usual FE solution. The stabilized schemes have been applied to compute fluids flow in various research fields. However, they have not been studied in the simulation of ion transport through three-dimensional models based on experimentally determined ion channel structures. In this paper, two stabilized techniques, the SUPG and the Pseudo Residual-Free Bubble function (PRFB) are introduced to enhance the numerical robustness and convergence performance of the finite element algorithm in ichannel. The conductances of the voltage dependent anion channel (VDAC) and the anthrax toxin protective antigen pore (PA) are simulated to validate the stabilization techniques. Those two stabilized schemes give reasonable results for the two proteins, with decent agreement with both experimental data and Brownian dynamics (BD) simulations. For a variety of numerical tests, it is found that the simulator effectively avoids previous numerical instability after introducing the stabilization methods. Comparison based on our test data set between the two stabilized schemes indicates both SUPG and PRFB have similar performance (the latter is slightly more accurate and stable), while SUPG is relatively more convenient to implement.

  4. Microbial acidification and pH effects on trace element release from sewage sludge.

    PubMed

    Qureshi, Shabnam; Richards, Brian K; Steenhuis, Tammo S; McBride, Murray B; Baveye, Philippe; Dousset, Sylvie

    2004-11-01

    Leaching of sludge-borne trace elements has been observed in experimental and field studies. The role of microbial processes in the mobilization of trace elements from wastewater sludge is poorly defined. Our objectives were to determine trace element mobilization from sludge subjected to treatments representing microbial acidification, direct chemical acidification and no acidification, and to determine the readsorption potential of mobilized elements using calcareous sand. Triplicate columns (10-cm diameter) for incubation and leaching of sludge had a top layer of digested dewatered sludge (either untreated, acidified with H2SO4, or limed with CaCO3; all mixed with glass beads to prevent ponding) and a lower glass bead support bed. Glass beads in the sludge layer, support layer or both were replaced by calcareous sand in four treatments used for testing the readsorption potential of mobilized elements. Eight sequential 8-day incubation and leaching cycles were operated, each consisting of 7.6 d of incubation at 28 degrees C followed by 8 h of leaching with synthetic acid rain applied at 0.25 cm/h. Leachates were analyzed for trace elements, nitrate and pH, and sludge layer microbial respiration was measured. The largest trace element, nitrate and S losses occurred in treatments with the greatest pH depression and greatest microbial respiration rates. Cumulative leaching losses from both microbial acidification and direct acidification treatments were > 90% of Zn and 64-80% of Cu and Ni. Preventing acidification with sludge layer lime or sand restricted leaching for all trace elements except Mo. Results suggested that the primary microbial role in the rapid leaching of trace elements was acidification, with results from direct acidification being nearly identical to microbial acidification. Microbial activity in the presence of materials that prevented acidification mobilized far lower concentrations of trace elements, with the exception of Mo. Trace elements

  5. Antibacterial Behavior of Additively Manufactured Porous Titanium with Nanotubular Surfaces Releasing Silver Ions.

    PubMed

    Amin Yavari, S; Loozen, L; Paganelli, F L; Bakhshandeh, S; Lietaert, K; Groot, J A; Fluit, A C; Boel, C H E; Alblas, J; Vogely, H C; Weinans, H; Zadpoor, A A

    2016-07-13

    Additive manufacturing (3D printing) has enabled fabrication of geometrically complex and fully interconnected porous biomaterials with huge surface areas that could be used for biofunctionalization to achieve multifunctional biomaterials. Covering the huge surface area of such porous titanium with nanotubes has been already shown to result in improved bone regeneration performance and implant fixation. In this study, we loaded TiO2 nanotubes with silver antimicrobial agents to equip them with an additional biofunctionality, i.e., antimicrobial behavior. An optimized anodizing protocol was used to create nanotubes on the entire surface area of direct metal printed porous titanium scaffolds. The nanotubes were then loaded by soaking them in three different concentrations (i.e., 0.02, 0.1, and 0.5 M) of AgNO3 solution. The antimicrobial behavior and cell viability of the developed biomaterials were assessed. As far as the early time points (i.e., up to 1 day) are concerned, the biomaterials were found to be extremely effective in preventing biofilm formation and decreasing the number of planktonic bacteria particularly for the middle and high concentrations of silver ions. Interestingly, nanotubes not loaded with antimicrobial agents also showed significantly smaller numbers of adherent bacteria at day 1, which may be attributed to the bactericidal effect of high aspect ratio nanotopographies. The specimens with the highest concentrations of antimicrobial agents adversely affected cell viability at day 1, but this effect is expected to decrease or disappear in the following days as the rate of release of silver ions was observed to markedly decrease within the next few days. The antimicrobial effects of the biomaterials, particularly the ones with the middle and high concentrations of antimicrobial agents, continued until 2 weeks. The potency of the developed biomaterials in decreasing the number of planktonic bacteria and hindering the formation of biofilms make

  6. Time study of trace elements and major ions during two cloud events at the Mt. Brocken

    NASA Astrophysics Data System (ADS)

    Plessow, K.; Acker, K.; Heinrichs, H.; Möller, D.

    Cloud water investigations have been performed at the highest elevation of Central Germany in 1997. Results of extensive trace element measurements are presented. Besides conductivity, pH, liquid water content and major ions the data set includes 49 minor and trace elements. Estimation of crustal enrichment factors (EFs) provides an indication of the anthropogenic contributions to the cloud water concentrations. The variation of cloud composition with time has been illustrated for two selected events with different air mass origins. The chemical composition of the cloud condensation nuclei on which the droplets grow mainly determines the cloud water chemistry. For a cloud event in June 1997 the concentrations of the crustally derived elements Si, Al, Fe, Ti, Ce, La and Nd follow each other closely. The fact that SO 42-, NO 3- and NH 4+ are only moderately correlated with the particular pollutants with high enrichment factors such as Cd, Sb, Pb, Zn, Cu, As, Bi, Sn, Mo, Ni, Tl and V indicates that their source regions are more widespread. During an event in October 1997 the time trends for most minor and trace elements follow rather closely those for the major ions NH 4+, SO 42- and NO 3-. Back trajectories show that the transport from continental and marine European sources was the likely cause of the sample concentrations. EFs of trace elements in cloud water samples during the June and October event show a strong correlation with those obtained for urban particulate matter. Although both events are influenced by air masses of different origin, there is a good agreement between the EF signatures.

  7. A New Radio Frequency Plasma Oxygen Primary Ion Source on Nano Secondary Ion Mass Spectrometry for Improved Lateral Resolution and Detection of Electropositive Elements at Single Cell Level.

    PubMed

    Malherbe, Julien; Penen, Florent; Isaure, Marie-Pierre; Frank, Julia; Hause, Gerd; Dobritzsch, Dirk; Gontier, Etienne; Horréard, François; Hillion, François; Schaumlöffel, Dirk

    2016-07-19

    An important application field of secondary ion mass spectrometry at the nanometer scale (NanoSIMS) is the detection of chemical elements and, in particular, metals at the subcellular level in biological samples. The detection of many trace metals requires an oxygen primary ion source to allow the generation of positive secondary ions with high yield in the NanoSIMS. The duoplasmatron oxygen source is commonly used in this ion microprobe but cannot achieve the same quality of images as the cesium primary ion source used to produce negative secondary ions (C(-), CN(-), S(-), P(-)) due to a larger primary ion beam size. In this paper, a new type of an oxygen ion source using a rf plasma is fitted and characterized on a NanoSIMS50L. The performances of this primary ion source in terms of current density and achievable lateral resolution have been characterized and compared to the conventional duoplasmatron and cesium sources. The new rf plasma oxygen source offered a net improvement in terms of primary beam current density compared to the commonly used duoplasmatron source, which resulted in higher ultimate lateral resolutions down to 37 nm and which provided a 5-45 times higher apparent sensitivity for electropositive elements. Other advantages include a better long-term stability and reduced maintenance. This new rf plasma oxygen primary ion source has been applied to the localization of essential macroelements and trace metals at basal levels in two biological models, cells of Chlamydomonas reinhardtii and Arabidopsis thaliana. PMID:27291826

  8. Ion microprobe elemental analyses of impact features on interplanetary dust experiment sensor surfaces

    NASA Technical Reports Server (NTRS)

    Hunter, Jerry L.; Wortman, Jim J.; Griffis, Dieter P.; Simon, Charles G.

    1991-01-01

    Hypervelocity impact features on several of the electro-active dust sensors utilized in the Interplanetary Dust Experiment (IDE) were subjected to elemental analysis using an ion microprobe. The negatively biased dust sensor surfaces acted as ion traps for cations produced in the plasma plumes of impacting particles. Impactor residue surrounds most impact features to two or three feature diameters. After etching away a layer of carbonaceous/silicaceous surface contamination, low mass resolution elemental survey scans are used to tentatively identify the presence of impactor debris. High mass resolution two-dimensional elemental maps and three dimensional depth profiling of the feature and surrounding area show the distribution and relative composition of the debris. The location of these sensors on the six primary Long Duration Exposure Facility (LDEF) sides provides a unique opportunity to further define the debris environment. Researchers applied the same techniques to impact and contaminant features on a set of ultra-pure, highly polished single crystal germanium wafer witness plates that were mounted on row 12 and exposed to the environment during the entire mission.

  9. Finite element simulation of the gating mechanism of mechanosensitive ion channels

    NASA Astrophysics Data System (ADS)

    Bavi, Navid; Qin, Qinghua; Martinac, Boris

    2013-08-01

    In order to eliminate limitations of existing experimental or computational methods (such as patch-clamp technique or molecular dynamic analysis) a finite element (FE) model for multi length-scale and time-scale investigation on the gating mechanism of mechanosensitive (MS) ion channels has been established. Gating force value (from typical patch clamping values) needed to activate Prokaryotic MS ion channels was applied as tensional force to the FE model of the lipid bilayer. Making use of the FE results, we have discussed the effects of the geometrical and the material properties of the Escherichia coli MscL mechanosensitive ion channel opening in relation to the membrane's Young's modulus (which will vary depending on the cell type or cholesterol density in an artificial membrane surrounding the MscL ion channel). The FE model has shown that when the cell membrane stiffens the required channel activation force increases considerably. This is in agreement with experimental results taken from the literature. In addition, the present study quantifies the relationship between the membrane stress distribution around a `hole' for modeling purposes and the stress concentration in the place transmembrane proteins attached to the hole by applying an appropriate mesh refinement as well as well defining contact condition in these areas.

  10. Ion selectivity of porcine skeletal muscle Ca2+ release channels is unaffected by the Arg615 to Cys615 mutation.

    PubMed Central

    Shomer, N H; Mickelson, J R; Louis, C F

    1994-01-01

    The Arg615 to Cys615 mutation of the sarcoplasmic reticulum (SR) Ca2+ release channel of malignant hyperthermia susceptible (MHS) pigs results in a decreased sensitivity of the channel to inhibitory Ca2+ concentrations. To investigate whether this mutation also affects the ion selectivity filter of the channel, the monovalent cation conductances and ion permeability ratios of single Ca2+ release channels incorporated into planar lipid bilayers were compared. Monovalent cation conductances in symmetrical solutions were: Li+, 183 pS +/- 3 (n = 21); Na+, 474 pS +/- 6 (n = 29); K+, 771 pS +/- 7 (n = 29); Rb+, 502 pS +/- 10 (n = 22); and Cs+, 527 pS +/- 5 (n = 16). The single-channel conductances of MHS and normal Ca2+ release channel were not significantly different for any of the monovalent cations tested. Permeability ratios measured under biionic conditions had the permeability sequence Ca2+ >> Li+ > Na+ > K+ > or Rb+ > Cs+, with no significant difference noted between MHS and normal channels. This systematic examination of the conduction properties of the pig skeletal muscle Ca2+ release channel indicated a higher Ca2+ selectivity (PCa2+:Pk+ approximately 15.5) than the sixfold Ca2+ selectivity previously reported for rabbit skeletal (Smith et al., 1988) or sheep cardiac muscle (Tinker et al., 1992) Ca2+ release channels. These results also indicate that although Ca2+ regulation of Ca2+ release channel activity is altered, the Arg615 to Cys615 mutation of the porcine Ca2+ release channel does not affect the conductance or ion selectivity properties of the channel. PMID:7948678

  11. Large-ion lithophile elements delivered by saline fluids to the sub-arc mantle

    NASA Astrophysics Data System (ADS)

    Kawamoto, Tatsuhiko; Mibe, Kenji; Bureau, Hélène; Reguer, Solenn; Mocuta, Cristian; Kubsky, Stefan; Thiaudière, Dominique; Ono, Shigeaki; Kogiso, Tetsu

    2014-12-01

    Geochemical signatures of arc basalts can be explained by addition of aqueous fluids, melts, and/or supercritical fluids from the subducting slab to the sub-arc mantle. Partitioning of large-ion lithophile elements between aqueous fluids and melts is crucial as these two liquid phases are present in the sub-arc pressure-temperature conditions. Using a micro-focused synchrotron X-ray beam, in situ X-ray fluorescence (XRF) spectra were obtained from aqueous fluids and haplogranite or jadeite melts at 0.3 to 1.3 GPa and 730°C to 830°C under varied concentrations of (Na, K)Cl (0 to 25 wt.%). Partition coefficients between the aqueous fluids and melts were calculated for Pb, Rb, and Sr ([InlineEquation not available: see fulltext.]). There was a positive correlation between [InlineEquation not available: see fulltext.] values and pressure, as well as [InlineEquation not available: see fulltext.] values and salinity. As compared to the saline fluids with 25 wt.% (Na, K)Cl, the Cl-free aqueous fluids can only dissolve one tenth (Pb, Rb) to one fifth (Sr) of the amount of large-ion lithophile elements when they coexist with the melts. In the systems with 13 to 25 wt.% (Na, K)Cl, [InlineEquation not available: see fulltext.] values were greater than unity, which is indicative of the capacity of such highly saline fluids to effectively transfer Pb and Rb. Enrichment of large-ion lithophile elements such as Pb and Rb in arc basalts relative to mid-oceanic ridge basalts (MORB) has been attributed to mantle source fertilization by aqueous fluids from dehydrating oceanic plates. Such aqueous fluids are likely to contain Cl, although the amount remains to be quantified.

  12. Synthesis of large FeSe superconductor crystals via ion release/introduction and property characterization

    NASA Astrophysics Data System (ADS)

    Dongna, Yuan; Yulong, Huang; Shunli, Ni; Huaxue, Zhou; Yiyuan, Mao; Wei, Hu; Jie, Yuan; Kui, Jin; Guangming, Zhang; Xiaoli, Dong; Fang, Zhou

    2016-07-01

    Large superconducting FeSe crystals of (001) orientation have been prepared via a hydrothermal ion release/introduction route for the first time. The hydrothermally derived FeSe crystals are up to 10 mm×5 mm×0.3 mm in dimension. The pure tetragonal FeSe phase has been confirmed by x-ray diffraction (XRD) and the composition determined by both inductively coupled plasma atomic emission spectroscopy (ICP-AES) and energy dispersive x-ray spectroscopy (EDX). The superconducting transition of the FeSe samples has been characterized by magnetic and transport measurements. The zero-temperature upper critical field H c2 is calculated to be 13.2–16.7 T from a two-band model. The normal-state cooperative paramagnetism is found to be predominated by strong spin frustrations below the characteristic temperature T sn, where the Ising spin nematicity has been discerned in the FeSe superconductor crystals as reported elsewhere. Project supported by the National Natural Science Foundation of China (Grant Nos. 11574370, 11274358, and 11190020), the National Basic Research Program of China (Grant No. 2013CB921700), and the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB07020100).

  13. The Potential Impacts on Aquatic Ecosystems from the Release of Trace Elements in Geothermal Fluids

    SciTech Connect

    Cushman, R.M.

    2000-03-14

    Geothermal energy will likely constitute an increasing percentage of our nation's future energy ''mix,'' both for electrical and nonelectrical uses. Associated with the exploitation of geothermal resources is the handling and disposal of fluids which contain a wide variety of potentially toxic trace elements. We present analyses of 14 trace elements found in hydrothermal fluids from various geothermal reservoirs in the western United States. The concentrations of these elements vary over orders of magnitude between reservoirs. Potential impacts are conservatively assessed on the basis of (1) toxicity to freshwater biota, and (2) bioaccumulation in food fish to the point where consumption might be hazardous to human health. Trace element concentrations generally range from benign levels to levels which might prove toxic to freshwater biota and contaminate food fisheries. We stress the need for site-specific analyses and careful handling of geothermal fluids in order to minimize potential impacts.

  14. In Situ Response of Nanostructured Hybrid Fluoridated Restorative Composites on Enamel Demineralization, Surface Roughness and Ion Release.

    PubMed

    Melo, Mary A S; Codes, Bruna M; Passos, Vanara F; Lima, Juliana P M; Rodrigues, Lidiany K A

    2014-12-01

    Recurrent caries at the tooth-restoration margins is the main reason for composite failure. Fluoride-releasing nanohybrid composite resin may reduce the recurrent caries rates. A fluoride-releasing resin (FCR) and non-fluoride-releasing resin (CR) were tested using an in situ model. Demineralization (ΔS), ion release and surface roughness of composite specimens were determined. The F concentration in the group FCR was higher than the CR group. ΔS (Mean ± SD) was 2579 ± 1582 and 1705 ± 1292, respectively, for FCR and CR. Surfaces roughness was altered by biofilm accumulation. The hybrid fluorated restorative composites containing nanoparticles have a slight anticaries action without alteration of surface smoothness of the material. PMID:26466443

  15. Functionalized Mesoporous Silica via an Aminosilane Surfactant Ion Exchange Reaction: Controlled Scaffold Design and Nitric Oxide Release

    PubMed Central

    2015-01-01

    Nitric oxide-releasing mesoporous silica nanoparticles (MSNs) were prepared using an aminosilane-template surfactant ion exchange reaction. Initially, bare silica particles were synthesized under basic conditions in the presence of cetyltrimethylammonium bromide (CTAB). These particles were functionalized with nitric oxide (NO) donor precursors (i.e., secondary amines) via the addition of aminosilane directly to the particle sol and a commensurate ion exchange reaction between the cationic aminosilanes and CTAB. N-Diazeniumdiolate NO donors were formed at the secondary amines to yield NO-releasing MSNs. Tuning of the ion exchange-based MSN modification approach allowed for the preparation of monodisperse particles ranging from 30 to 1100 nm. Regardless of size, the MSNs stored appreciable levels of NO (0.4–1.5 μmol mg–1) with tunable NO release durations (1–33 h) dependent on the aminosilane modification. Independent control of NO release properties and particle size was achieved, demonstrating the flexibility of this novel MSN synthesis over conventional co-condensation and surface grafting strategies. PMID:26717238

  16. Hornblende-melt trace-element partitioning measured by ion microprobe

    USGS Publications Warehouse

    Sisson, T.W.

    1994-01-01

    Trace-element abundances were measured in situ by ion microprobe in five samples of hornblende and melt ranging from basaltic andesite to high-silica rhyolite. Except for one sample, for which quench overgrowth or disequilibrium is suspected, the abundance ratios show systematic inter-element and inter-sample variations, and probably approach true partition coefficients. Apparent partition coefficients are reported for La, Ce, Nd, Sm, Dy, Er, Yb, Sc, Ti, V, Cr, Sr, Y and Zr. Rare-earth elements (REE) and Y form smooth convex-upward partitioning patterns that rise to higher D-values and become increasingly convex in more evolved samples. Apparent partition coefficients for REE, Y, Ti, V and Cr can be parameterized as functions of the distribution of Ca between hornblende and melt, giving expressions to predict hornblende-melt trace-element partitioning values. These expressions are used to show that heavy REE-enriched hornblende/whole-rock REE abundance patterns in granitoids may result from partial re-equilibration of hornblende and late-stage residual liquids rather than from anomalous partitioning values. ?? 1994.

  17. Neutron interrogation to identify chemical elements with an ion-tube neutron source (INS)

    SciTech Connect

    Alvarez, R.A.; Dougan, A.D.; Rowland, M.R.; Wang, T.F.

    1994-04-07

    A non-destructive analysis technique using a portable, electric ion-tube neutron source (INS) and gamma ray detector has been used to identify the key constituent elements in a number of sealed munitions, and from the elemental makeup, infer the types of agent within each. The high energy (14 MeV) and pulsed character of the neutron flux from an INS provide a method of measuring, quantitatively, the oxygen, carbon, and fluorine content of materials in closed containers, as well as the other constituents that can be measured with low-energy neutron probes. The broad range of elements that can be quantitatively measured with INS-based instruments provides a capability of verifying common munition fills; it provides the greatest specificity of any portable neutron-based technique for determining the full matrix of chemical elements in completely unrestricted sample scenarios. The specific capability of quantifying the carbon and oxygen content of materials should lead to a fast screening technique which, can discriminate very quickly between high-explosive and chemical agent-filled containers.

  18. Strain energy release rate determination of stress intensity factors by finite element methods

    NASA Technical Reports Server (NTRS)

    Walsh, R. M., Jr.; Pipes, R. B.

    1985-01-01

    The stiffness derivative finite element technique is used to determine the Mode I stress intensity factors for three-crack configurations. The geometries examined include the double edge notch, single edge notch, and the center crack. The results indicate that when the specified guidelines of the Stiffness Derivative Method are used, a high degree of accuracy can be achieved with an optimized, relatively coarse finite element mesh composed of standard, four-node, plane strain, quadrilateral elements. The numerically generated solutions, when compared with analytical ones, yield results within 0.001 percent of each other for the double edge crack, 0.858 percent for the single edge crack, and 2.021 percent for the center crack.

  19. Early time evolution of negative ion clouds and electron density depletions produced during electron attachment chemical release experiments

    NASA Technical Reports Server (NTRS)

    Scales, W. A.; Bernhardt, P. A.; Ganguli, G.

    1994-01-01

    Two-dimensional electrostatic particle-in-cell simulations are used to study the early time evolution of electron depletions and negative ion clouds produced during electron attachment chemical releases in the ionosphere. The simulation model considers the evolution in the plane perpendicular to the magnetic field and a three-species plasma that contains electrons, positive ions, and also heavy negative ions that result as a by-product of the electron attachment reaction. The early time evolution (less than the negative ion cyclotron period) of the system shows that a negative charge surplus initially develops outside of the depletion boundary as the heavy negative ions move across the boundary. The electrons are initially restricted from moving into the depletion due to the magnetic field. An inhomogenous electric field develops across the boundary layer due to this charge separation. A highly sheared electron flow velocity develops in the depletion boundary due to E x B and Delta-N x B drifts that result from electron density gradients and this inhomogenous electric field. Structure eventually develops in the depletion boundary layer due to low-frequency electrostatic waves that have growth times shorter than the negative ion cyclotron period. It is proposed that these waves are most likely produced by the electron-ion hybrid instability that results from sufficiently large shears in the electron flow velocity.

  20. X-Rays of Heavy Elements for Nanotechnological Applications:. W and Pb Ions

    NASA Astrophysics Data System (ADS)

    Nahar, Sultana N.

    2013-03-01

    Heavy elements can absorb or emit hard X-rays and hence are commonly implemented in various high energy nanotechnological applications. The absorptin or emission occurs mainly through the 1s-2p (Kα) transitions, and the process can be used as the source for production of radiation or electron in the applications. For enhanced productions of electrons and photons in the nanobiomedical applications, investigations have focused on the K-shell ionization of the atom or ion. This is because of the well-known rise in photoionization at the K-shell ionization threshold. However, experimental investigations to find any evidence of this rise has not been successful. We have developed a new method called Resonant Theranostics for biomedical applications, where we show that the energy for the rise is related to 1s-np, particularly to 1s-2p transitions which appear as resonances in the photoionization for heavy elements. The energy for the 1s-2p transitions varies some with the ionic state of the element and gives a narrow band resonant energy for the element. The strength of the process depends on the oscillator strength of the transitions. This report will demonstrate these through illustrations of the resonant energy range and strengths of photoabsorption due to K-alpha transitions using some elements, such as tungsten (W, Z=74) and lead (Pb, Z=82). An X-ray photon can ionize a high-Z element by ejection of a K-shell electron. This will create a hole or vacancy which, through the Auger process, will be filled out by an upper shell electron with emission of a photon. Such process at the resonant energy can lead to Koster-Kronig cascade giving out a number of photons and electrons as the element goes through various ionic states and can be modeled using the oscillator strengths. Such emissions are highly desirable in radiation therapy application. Present illustrations will include electric dipole allowed transitions for nine ionic states, from hydrogen to fluorine like ions

  1. DEVOLATILIZATION KINETICS AND ELEMENTAL RELEASE IN THE PYROLYSIS OF PULVERIZED COAL

    EPA Science Inventory

    The report gives results of a study of the evolution of volatile matter and trace elements from pulverized coal during pyrolysis in an inert atmosphere, using batch and laminar flow furnace reactors. Five coals were used, ranging in rank from lignite to anthracite. Data on transi...

  2. Mechanical characterization of several ion-implanted alloys: nanoindentation testing, wear testing and finite element modeling

    NASA Astrophysics Data System (ADS)

    Bourcier, R. J.; Follstaedt, D. M.; Dugger, M. T.; Myers, S. M.

    1991-07-01

    The influence of ion implantation on the mechanical properties of metal alloys has been examined using a variety of experimental and numerical techniques. Ultralow load indentation testing and finite element modeling has been used for the aluminum/oxygen to extract fundamental mechanical properties. Aluminum implanted with 20 at.% O exhibits extraordinary strength, as high as 3300 MPa. The degree of strengthening expected for this Al(O) alloy on the basis of the observed microstructure of fine (1.5-3.5 nm) oxide precipitates was estimated using several micromechanical models, and the results agree with our experimental findings. Pin-on-disk tribological characterization of aluminum implanted with 10 at.% oxygen revealed that the ion-beam treatment reduced the average friction coefficient from greater than 1.0 (for pure Al) to approximately 0.25 (for Al(O)). Large-amplitude stick-slip oscillations, which occur within the first two cycles for pure aluminum, were postponed to 30-50 cycles for the ion-implanted material. Two stainless steels which have been amorphized by implantation, 304 implanted with C and 440C implanted with Ti + C, show measurable hardening with implantation, of the order of 40 and 15%, respectively. In addition, nanoindentation within pin-on-disk wear tracks on 440C reveals that the mechanical state of the extensively deformed implanted layer is apparently unchanged from its initial state.

  3. In situ cross-linking of sodium alginate with calcium and aluminum ions to sustain the release of theophylline from polymeric matrices.

    PubMed

    Nokhodchi, Ali; Tailor, Anish

    2004-12-01

    Small matrices of calcium alginate or aluminium alginate have been investigated as possible controlled release systems for drugs. The objective of the present study was to sustain the release of theophylline from alginate matrices using different concentrations of aluminium chloride and calcium chloride in presence and absence of HPMC. Tablets containing differing concentrations of aluminium and calcium chloride were produced and the release rate of theophylline was tested using the basket dissolution apparatus over 8 h. Increasing amounts of aluminium chloride from 0.0001 to 0.00068 moles decreased the release of theophylline from 95.1 +/- 0.27 to 29.5 +/- 1.5, indicating a significant effect of aluminium ions on a reduction in the release rate of theophylline from sodium alginate matrices. In the case of matrices containing different concentrations of calcium ions, as the concentration of calcium chloride increased, the release rate increased to an optimum then declined after this. This was due to insufficient calcium ions being available to cross-link with the sodium alginate to form an insoluble gel. The effect of aluminium ions, as this is a trivalent ion compared to calcium, which is a divalent ion, aluminium ions are able to decrease the release rate with a smaller concentration compared to calcium ions. The results also showed that the presence of HPMC caused a reduction in release rate of theophylline from alginate matrices containing calcium chloride. Whereas, in the case of alginate matrices containing aluminium chloride the release rate of theophylline increased in presence of HPMC. For comparing the dissolution data, dissolution efficiency (DE) was used. The values of DE are consistent with the dissolution data. The results show that within a formulation series, DE values generally decrease when the cation concentration increases and this criterion can be used to describe the effect of calcium and aluminium ions on the release behaviour of theophylline

  4. Scanning electrochemical microscopy of metallic biomaterials: reaction rate and ion release imaging modes.

    PubMed

    Gilbert, J L; Smith, S M; Lautenschlager, E P

    1993-11-01

    The Scanning Electrochemical Microscope (SECM) is a nonoptical scanning microscopic instrument capable of imaging highly localized electrical currents associated with charge transfer reactions on metallic biomaterials surfaces. The SECM operates as an aqueous electrochemical cell under bipotentiostatic control with a microelectrode and sample independently biased as working electrodes. Microelectrode current and position is recorded as it is scanned very near a metallurgically polished planar sample surface. To date, the SECM has imaged metallic biomaterials surfaces in oxygen reaction rate imaging (ORRI) and ion release and deposition imaging (IRDI) modes. In ORRI, sample and microelectrode are biased at sufficiently negative potentials to reduce absorbed oxygen. As the microelectrode scans areas of active oxygen reduction, localized diffusion fields with decreased oxygen solution concentrations are encountered and resultant decrements in microelectrode current are observed. In IRDI mode the sample is positively biased and the microelectrode is negatively biased. The microelectrode detects anodic dissolution products with highest currents being observed over the most active areas. Performance of the SECM has been evaluated on Ni minigrids, gamma-1 Hg-Ag dental amalgam crystals, and sintered beads of Co-Cr-Mo alloy which represent significantly different geometries and corrosion processes to help demonstrate the potential of this instrument. The SECM is a valuable tool for imaging microelectrochemical processes on the surfaces of metallurgically polished metallic biomaterials samples and a wide variety of other surfaces of biological interest where charge transfer reactions occur. The SECM allows selective biasing of metallic biomaterials surfaces and Faradaic reactions can be selectively imaged while the surface is in the active, passive, or transpassive state. PMID:8262998

  5. H-isotope retention and thermal/ion-induced release in boronized films

    SciTech Connect

    Walsh, D.S. ); Doyle, B.L.; Wampler, W.R.; Hays, A.K. )

    1990-01-01

    Over the past decade, it has been clearly demonstrated that the composition of the very near surface ({approximately}100nm) of plasma-interactive components plays a determinant role in most processes which occur in the plasma-edge of Tokamaks. Two very successful techniques to effect control of the plasma-wall interaction are (1) in-situ deposition of amorphous carbon or boron-carbon films and (2) the use of He/C conditioning discharges or He glow discharge cleaning to modify the near surface of bulk graphite components. We have deposited boronized layers into Si using plasma-assisted CVD and sputter deposition. The PCVD deposition conditions were as close as possible to those used in TFTR, and some films deposited in TFTR have also been studied. Using these two deposition techniques, B{sub x}CH{sub y} films have been produced with x varying from 1/2 -- 4, and y from {approximately}1 (sputtered) to {approximately}3 (PCVD). Most films also contained significant amounts of 0. Thermal and ion-induced release of H-isotopes from BC films is qualitatively similar to that measured for graphite. Implanted H saturates in these films at a H/host atom ratio of 0.7 which is considerably higher than that of graphite({approximately}0.4). As-deposited PCVD films are already saturated with H, while sputtered films are not. Sputtered BC films therefore possess an inherent H-pumping capability which could prove to be extremely beneficial to TFTR. 16 refs., 5 figs., 1 tab.

  6. Solar Ion Processing of Major Element Surface Compositions of Mature Mare Soils: Insights from Combined XPS and Analytical TEM Observations

    NASA Technical Reports Server (NTRS)

    Christoffersen, R.; Dukes, C.; Keller, L. P.; Baragiola, R.

    2012-01-01

    Solar wind ions are capable of altering the sur-face chemistry of the lunar regolith by a number of mechanisms including preferential sputtering, radiation-enhanced diffusion and sputter erosion of space weathered surfaces containing pre-existing compositional profiles. We have previously reported in-situ ion irradiation experiments supported by X-ray photoelectron spectroscopy (XPS) and analytical TEM that show how solar ions potentially drive Fe and Ti reduction at the monolayer scale as well as the 10-100 nm depth scale in lunar soils [1]. Here we report experimental data on the effect of ion irradiation on the major element surface composition in a mature mare soil.

  7. Evaluation of calcium ion release and change in pH on combining calcium hydroxide with different vehicles

    PubMed Central

    Grover, Charu; Shetty, Neeta

    2014-01-01

    Introduction: Intracanal medicaments have traditionally been used in endodontics to disinfect root canals between appointments. Calcium hydroxide is widely used as an intracanal medicament for disinfection and to promote periapical healing. It is stable for long periods, harmless to the body, and bactericidal in a limited area. The efficacy of calcium hydroxide as a disinfectant is dependent on the availability of the hydroxyl ions in the solution that depends on the vehicle in which the calcium hydroxide is carried. In general, three types of vehicles are used: Aqueous, viscous or oily. Some in vitro studies have shown that the type of vehicle has a direct relationship with the concentration and the velocity of ionic liberation as well as with the antibacterial action when the paste is carried into a contaminated area. Aim of the Study: To evaluate the calcium ion release and measure the change in pH of the environment that occurred when calcium hydroxide was combined with different vehicles (distilled water, propylene glycol, calcium hydroxide containing gutta-percha points and chitosan) over different time periods. Materials and Methods: Forty single rooted mandibular first premolar teeth were decoronated for this study. Working length was established and the root canals were enlarged and irrigation accomplished with 2 ml of NaOCl solution after every file. The teeth were then randomly divided into four groups. The canals were then packed with different preparations of calcium hydroxide using the following vehicles-distilled water, propylene glycol, gutta-percha points and chitosan. Calcium ion release in different groups was analyzed using an ultraviolet spectrophotometer at 220 nm. The change in pH of was determined using a pH meter. Results were statistically evaluated using one-way ANOVA test. Result: For calcium ion release, Group 2 showed cumulative drug release of 81.97% at the end of 15 days, whereas Group 1, 3 and 4 showed a release of 99.53, 17.98, 74

  8. The Double Solid Reactant Method for modeling the release of trace elements from dissolving solid phases: I. Outline and limitations

    NASA Astrophysics Data System (ADS)

    Accornero, Marina; Marini, Luigi

    2008-10-01

    A Double Solid Reactant Method was elaborated from a suggestion of Marini (Geological sequestration of carbon dioxide: Thermodynamics, kinetics, and reaction path modeling. Developments in Geochemistry, Elsevier, Amsterdam, 2007) to simulate the release of trace elements during the progressive dissolution of solid phases. The method is based on the definition, for each dissolving solid, of both an entity whose thermodynamic and kinetic properties are known (either a pure mineral or a solid mixture) and a special reactant, that is, a material of known stoichiometry and unknown thermodynamic and kinetic properties. The special reactant is utilised to take into account the concentrations of trace elements in the dissolving solid phase. In this communication, the influence of several trace elements on the Δ G f o, Δ G r o and log K of the minerals considered by Lelli et al. (Environ Geol, 2007) and Accornero and Marini (Geobasi, 2007a; Proceedings of IMWA symposium, Cagliari, 27 31 May 2007b) was evaluated assuming ideal mixing in the solid state. These effects were found to be negligible for albite and the leucite latitic glass, limited for muscovites and chlorites, and slightly more important for apatites. These influences become progressively higher with increasing concentration of trace elements in these minerals. Based on these deviations in thermodynamic parameters, special reactants should not include oxide components with molar fractions higher than 0.003.

  9. Application of alpha spectrometry to the discovery of new elements by heavy-ion-beam bombardment

    SciTech Connect

    Nitschke, J.M.

    1983-05-01

    Starting with polonium in 1898, ..cap alpha..-spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, ..cap alpha..-spectra have proved simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the natural ..cap alpha..-decay series led to the very powerful method of genetically linking the decay of new elements to the well-established ..cap alpha..-emission of daughter and granddaughter nuclei. This technique has been used for all recent discoveries of new elements including Z = 109. Up to mendelevium (Z = 101), thin samples suitable for ..cap alpha..-spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in He gas. Subsequent electrical deposition or a He-jet technique yielded samples that were not only thin enough for ..cap alpha..-spectroscopy, but also for ..cap alpha..- and ..beta..-recoil experiments. Many variations of these methods have been developed and are discussed. For the synthesis of element 106 an aerosol-based recoil transport technique was devised. In the most recent experiments, ..cap alpha..-spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10/sup -6/ s; while it was 10/sup -1/ to 10/sup 0/ s for He-jets and 10/sup 1/ to 10/sup 3/ s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyze them with these latest techniques. Again, ..cap alpha..-spectrometry will play a major role since the expected signature for the decay of a SHE is a sequence of ..cap alpha..-decays followed by spontaneous fission.

  10. Galvanic Corrosion of and Ion Release from Various Orthodontic Brackets and Wires in a Fluoride-containing Mouthwash

    PubMed Central

    Tahmasbi, Soodeh; Ghorbani, Mohammad; Masudrad, Mahdis

    2015-01-01

    Background and aims. This study compared the galvanic corrosion of orthodontic wires and brackets from various manufacturers following exposure to a fluoride mouthwash. Materials and methods. This study was conducted on 24 lower central incisor 0.022" Roth brackets of four different commercially available brands (Dentaurum, American Orthodontics, ORJ, Shinye). These brackets along with stainless steel (SS) or nickel-titanium (NiTi) orthodontic wires (0.016", round) were immersed in Oral-B mouthwash containing 0.05% sodium fluoride for 28 days. The electric potential (EP) difference of each bracket-wire couple was measured with a Saturated Calomel Reference Electrode (Ag/AgCl saturated with KCl) via a voltmeter. The ions released in the electrolyte weremeasured with an atomic absorption spectrometer. All the specimens were assessed under a stereomicroscope and specimens with corrosion were analyzed with scanning electron microscopy (SEM). Data were analyzed using ANOVA. Results. The copper ions released from specimens with NiTi wire were greater than those of samples containing SS wire. ORJ brackets released more Cu ions than other samples. The Ni ions released from Shinye brackets were significantly more than those of other specimens (P < 0.05). Corrosion rate of brackets coupled with NiTi wires was higher than that of brackets coupled with SS wires. Light and electron microscopic observations showed greater corrosion of ORJ brackets. Conclusion. In fluoride mouthwash, Shinye and ORJ brackets exhibited greater corrosion than Dentaurum and American Orthodontics brackets. Stainless steel brackets used with NiTi wires showed greater corrosion and thus caution is recommended when using them. PMID:26697148

  11. Galvanic Corrosion of and Ion Release from Various Orthodontic Brackets and Wires in a Fluoride-containing Mouthwash.

    PubMed

    Tahmasbi, Soodeh; Ghorbani, Mohammad; Masudrad, Mahdis

    2015-01-01

    Background and aims. This study compared the galvanic corrosion of orthodontic wires and brackets from various manufacturers following exposure to a fluoride mouthwash. Materials and methods. This study was conducted on 24 lower central incisor 0.022" Roth brackets of four different commercially available brands (Dentaurum, American Orthodontics, ORJ, Shinye). These brackets along with stainless steel (SS) or nickel-titanium (NiTi) orthodontic wires (0.016", round) were immersed in Oral-B mouthwash containing 0.05% sodium fluoride for 28 days. The electric potential (EP) difference of each bracket-wire couple was measured with a Saturated Calomel Reference Electrode (Ag/AgCl saturated with KCl) via a voltmeter. The ions released in the electrolyte weremeasured with an atomic absorption spectrometer. All the specimens were assessed under a stereomicroscope and specimens with corrosion were analyzed with scanning electron microscopy (SEM). Data were analyzed using ANOVA. Results. The copper ions released from specimens with NiTi wire were greater than those of samples containing SS wire. ORJ brackets released more Cu ions than other samples. The Ni ions released from Shinye brackets were significantly more than those of other specimens (P < 0.05). Corrosion rate of brackets coupled with NiTi wires was higher than that of brackets coupled with SS wires. Light and electron microscopic observations showed greater corrosion of ORJ brackets. Conclusion. In fluoride mouthwash, Shinye and ORJ brackets exhibited greater corrosion than Dentaurum and American Orthodontics brackets. Stainless steel brackets used with NiTi wires showed greater corrosion and thus caution is recommended when using them. PMID:26697148

  12. Laser-based directed release of array elements for efficient collection into targeted microwells.

    PubMed

    Dobes, Nicholas C; Dhopeshwarkar, Rahul; Henley, W Hampton; Ramsey, J Michael; Sims, Christopher E; Allbritton, Nancy L

    2013-02-21

    A cell separation strategy capable of the systematic isolation and collection of moderate to large numbers (25-400) of single cells into a targeted microwell is demonstrated. An array of microfabricated, releasable, transparent micron-scale pedestals termed pallets and an array of microwells in poly(dimethylsiloxane) (PDMS) were mated to enable selective release and retrieval of individual cells. Cells cultured on a pallet array mounted on a custom designed stage permitted the array to be positioned independently of the microwell locations. Individual pallets containing cells were detached in a targeted fashion using a pulsed Nd:YAG laser. The location of the laser focal point was optimized to transfer individual pallets to designated microwells. In a large-scale sort (n = 401), the accuracy, defined as placing a pallet in the intended well, was 94% and the collection efficiency was 100%. Multiple pallets were observed in only 4% of the targeted wells. In cell sorting experiments, the technique provided a yield and purity of target cells identified by their fluorescence signature of 91% and 93%, respectively. Cell viability based on single-cell cloning efficiency at 72 h post collection was 77%. PMID:23223411

  13. Trace element release from estuarine sediments of South Mosquito Lagoon near Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Menon, M. P.; Ghuman, G. S.; Emeh, C. O.

    1979-01-01

    Analytical partitioning of four trace metals in estuarine sediments collected from eight sites in South Mosquito Lagoon near Kennedy Space Center, in terms of four different categories was accomplished using four different extraction techniques. The concentrations of the four trace metals, Zn, Mn, Cd, and Cu, released in interstitial water extract, 1 N ammonium acetate extract, conc. HCl extract and fusion extract of sediments as well as their concentrations in water samples collected from the same location were determined using flame atomic absorption technique. From the analytical results the percentages of total amount of each metal distributed among four different categories, interstitial water phase, acetate extractable, acid extractable and detrital crystalline material, were determined. Our results suggest that analytical partitioning of trace metals in estuarine sediments may be used to study the mechanism of incorporation of trace metals with sediments from natural waters. A correlation between the seasonal variation in the concentration of acetate extractable trace metals in the sediment and similar variation in their concentration in water was observed. A mechanism for the release of trace metals from estuarine sediments to natural water is also suggested.

  14. Laser-Based Directed Release of Array Elements for Efficient Collection into Targeted Microwells

    PubMed Central

    Dobes, Nicholas C.; Dhopeshwarkar, Rahul; Henley, W. Hampton; Ramsey, J. Michael; Sims, Christopher E.; Allbritton, Nancy L.

    2013-01-01

    A cell separation strategy capable of the systematic isolation and collection of moderate to large numbers (25–400) of single cells into a targeted microwell is demonstrated. An array of microfabricated, releasable, transparent micron-scale pedestals termed pallets and an array of microwells in poly(dimethylsiloxane) (PDMS) were mated to enable selective release and retrieval of individual cells. Cells cultured on a pallet array mounted on a custom designed stage permitted the array to be positioned independently of the microwell locations. Individual pallets containing cells were detached in a targeted fashion using a pulsed Nd:YAG laser. The location of the laser focal point was optimized to transfer individual pallets to designated microwells. In a large-scale sort (n = 401), the accuracy, defined as placing a pallet in the intended well, was 94% and the collection efficiency was 100%. Multiple pallets were observed in only 4% of the targeted wells. In cell sorting experiments, the technique provided a yield and purity of target cells identified by their fluorescence signature of 91% and 93%, respectively. Cell viability based on single-cell cloning efficiency at 72 h post collection was 77%. PMID:23223411

  15. Effect of different cleansers on the weight and ion release of removable partial denture: an in vitro study

    PubMed Central

    FELIPUCCI, Daniela N.B.; DAVI, Letícia R.; PARANHOS, Helena F.O.; BEZZON, Osvaldo L.; SILVA, Rodrigo F.; BARBOSA JUNIOR, Fernando; PAGNANO, Valéria O.

    2011-01-01

    Objective Removable partial dentures (RPD) require different hygiene care, and association of brushing and chemical cleansing is the most recommended to control biofilm formation. However, the effect of cleansers has not been evaluated in RPD metallic components. The aim of this study was to evaluate in vitro the effect of different denture cleansers on the weight and ion release of RPD. Material and Methods Five specimens (12x3 mm metallic disc positioned in a 38x18x4 mm mould filled with resin), 7 cleanser agents [Periogard (PE), Cepacol (CE), Corega Tabs (CT), Medical Interporous (MI), Polident (PO), 0.05% sodium hypochlorite (NaOCl), and distilled water (DW) (control)] and 2 cobalt-chromium alloys [DeguDent (DD), and VeraPDI (VPDI)] were used for each experimental situation. One hundred and eighty immersions were performed and the weight was analyzed with a high precision analytic balance. Data were recorded before and after the immersions. The ion release was analyzed using mass spectrometry with inductively coupled plasma. Data were analyzed by two-way ANOVA and Tukey HSD post hoc test at 5% significance level. Results Statistical analysis showed that CT and MI had higher values of weight loss with higher change in VPDI alloy compared to DD. The solutions that caused more ion release were NaOCl and MI. Conclusions It may be concluded that 0.05% NaOCl and Medical Interporous tablets are not suitable as auxiliary chemical solutions for RPD care. PMID:21986653

  16. Novel, silver-ion-releasing nanofibrous scaffolds exhibit excellent antibacterial efficacy without the use of silver nanoparticles.

    PubMed

    Mohiti-Asli, Mahsa; Pourdeyhimi, Behnam; Loboa, Elizabeth G

    2014-05-01

    Nanofibers, with their morphological similarities to the extracellular matrix of skin, hold great potential for skin tissue engineering. Over the last decade, silver nanoparticles have been extensively investigated in wound-healing applications for their ability to provide antimicrobial benefits to nanofibrous scaffolds. However, the use of silver nanoparticles has raised concerns as these particles can penetrate into the stratum corneum of skin, or even diffuse into the cellular plasma membrane. We present and evaluate a new silver ion release polymeric coating that we have found can be applied to biocompatible, biodegradable poly(l-lactic acid) nanofibrous scaffolds. Using this compound, custom antimicrobial silver-ion-releasing nanofibers were created. The presence of a uniform, continuous silver coating on the nanofibrous scaffolds was verified by XPS analysis. The antimicrobial efficacy of the antimicrobial scaffolds against Staphylococcus aureus and Escherichia coli bacteria was determined via industry-standard AATCC protocols. Cytotoxicity analyses of the antimicrobial scaffolds toward human epidermal keratinocytes and human dermal fibroblasts were performed via quantitative analyses of cell viability and proliferation. Our results indicated that the custom antimicrobial scaffolds exhibited excellent antimicrobial properties while also maintaining human skin cell viability and proliferation for silver ion concentrations below 62.5μgml(-1) within the coating solution. This is the first study to show that silver ions can be effectively delivered with nanofibrous scaffolds without the use of silver nanoparticles. PMID:24365706

  17. Release of nickel and chromium ions in the saliva of patients with fixed orthodontic appliance: An in-vivo study

    PubMed Central

    Dwivedi, Anoop; Tikku, Tripti; Khanna, Rohit; Maurya, Rana Pratap; Verma, Geeta; Murthy, R. C.

    2015-01-01

    Introduction: Various components of fixed orthodontic appliances are continuously interacting with saliva and other fluids in the mouth releasing various metal ions including nickel and chromium that can cause damaging effects if their concentration exceeds above the toxic dose. Aim: To determine and compare the level of nickel and chromium in the saliva of patients undergoing fixed orthodontic treatment at different time periods. Materials and Methods: The sample of saliva of 13 patients was taken at different time periods that is: Group 1 (before appliance placement), Group II, III, and IV (after 1-week, 1-month, and 3 months of appliance placement respectively). The fixed appliance comprised of brackets, bands, buccal tubes, lingual sheath, transpalatal arch and wires composed of Ni-Ti and stainless steel. The level of ions was determined using graphite furnace atomic absorption spectro-photometry. The data thus obtained were statistically analyzed using SPSS Statistical Analysis Software (Version 15.0). Results: Level of nickel and chromium in saliva was highest in Group II and lowest in Groups I for both the ions. On comparison among different Groups, it was statistically significant for all the groups (<0.001) except between Group III and Group IV. Conclusion: The release of nickel and chromium was maximum at 1-week and then the level gradually declined. These values were well below the toxic dose of these ions. The results should be viewed with caution in subjects with Ni hypersensitivity. PMID:26668455

  18. Manufacturing and characterization of a ceramic microcombustor with integrated oxygen storage and release element

    NASA Astrophysics Data System (ADS)

    Khaji, Z.; Sturesson, P.; Klintberg, L.; Hjort, K.; Thornell, G.

    2015-10-01

    A microscale ceramic high-temperature combustor with a built-in temperature sensor and source of oxygen has been designed, manufactured and characterized. The successful in situ electroplating and oxidation of copper, and the use of copper oxide as the source of oxygen were demonstrated. It was shown that residual stresses from electroplating, copper oxidation and oxide decomposition did not cause much deformation of the substrate but influenced mainly the integrity and adhesion of the metal films. The process had influence on the electrical resistances, however. Calibration of the temperature sensor and correlation with IR thermography up to 1000 °C revealed a nearly linear sensor behavior. Demonstration of combustion in a vacuum chamber proved that no combustion had occurred before release of oxygen from the metal oxide resource.

  19. Environmental risk of particulate and soluble platinum group elements released from gasoline and diesel engine catalytic converters.

    PubMed

    Moldovan, M; Palacios, M A; Gómez, M M; Morrison, G; Rauch, S; McLeod, C; Ma, R; Caroli, S; Alimonti, A; Petrucci, F; Bocca, B; Schramel, P; Zischka, M; Pettersson, C; Wass, U; Luna, M; Saenz, J C; Santamaría, J

    2002-09-16

    A comparison of platinum-group element (PGE) emission between gasoline and diesel engine catalytic converters is reported within this work. Whole raw exhaust fumes from four catalysts of three different types were examined during their useful lifetime, from fresh to 80,000 km. Two were gasoline engine catalysts (Pt-Pd-Rh and Pd-Rh), while the other two were diesel engine catalysts (Pt). Samples were collected following the 91441 EUDC driving cycle for light-duty vehicle testing, and the sample collection device used allowed differentiation between the particulate and soluble fractions, the latter being the most relevant from an environmental point of view. Analyses were performed by inductively coupled plasma-mass spectrometry (ICP-MS) (quadrupole and high resolution), and special attention was paid to the control of spectral interference, especially in the case of Pd and Rh. The results obtained show that, for fresh catalysts, the release of particulate PGE through car exhaust fumes does not follow any particular trend, with a wide range (one-two orders of magnitude) for the content of noble metals emitted. The samples collected from 30,000-80,000 km present a more homogeneous PGE release for all catalysts studied. A decrease of approximately one order of magnitude is observed with respect to the release from fresh catalysts, except in the case of the diesel engine catalyst, for which PGE emission continued to be higher than in the case of gasoline engines. The fraction of soluble PGE was found to represent less than 10% of the total amount released from fresh catalysts. For aged catalysts, the figures are significantly higher, especially for Pd and Rh. Particulate PGE can be considered as virtually biologically inert, while soluble PGE forms can represent an environmental risk due to their bioavailability, which leads them to accumulate in the environment. PMID:12398337

  20. Iron sulfide attenuates the methanogenic toxicity of elemental copper and zinc oxide nanoparticles and their soluble metal ion analogs.

    PubMed

    Gonzalez-Estrella, Jorge; Gallagher, Sara; Sierra-Alvarez, Reyes; Field, Jim A

    2016-04-01

    Elemental copper (Cu(0)) and zinc oxide (ZnO) nanoparticle (NP) toxicity to methanogens has been attributed to the release of soluble metal ions. Iron sulfide (FeS) partially controls the soluble concentration of heavy metals and their toxicity in aquatic environments. Heavy metals displace the Fe from FeS forming poorly soluble metal sulfides in the FeS matrix. Therefore, FeS may be expected to attenuate the NP toxicity. This work assessed FeS as an attenuator of the methanogenic toxicity of Cu(0) and ZnO NPs and their soluble salt analogs. The toxicity attenuation capacity of fine (25-75μm) and coarse (500 to 1200μm) preparations of FeS (FeS-f and FeS-c respectively) was tested in the presence of highly inhibitory concentrations of CuCl2, ZnCl2 Cu(0) and ZnO NPs. FeS-f attenuated methanogenic toxicity better than FeS-c. The results revealed that 2.5× less FeS-f than FeS-c was required to recover the methanogenic activity to 50% (activity normalized to uninhibited controls). The results also indicated that a molar FeS-f/Cu(0) NP, FeS-f/ZnO NP, FeS-f/ZnCl2, and FeS-f/CuCl2 ratio of 2.14, 2.14, 4.28, and 8.56 respectively, was necessary to recover the methanogenic activity to >75%. Displacement experiments demonstrated that CuCl2 and ZnCl2 partially displaced Fe from FeS. As a whole, the results indicate that not all the sulfide in FeS was readily available to react with the soluble Cu and Zn ions which may explain the need for a large stoichiometric excess of FeS to highly attenuate Cu and Zn toxicity. Overall, this study provides evidence that FeS attenuates the toxicity caused by Cu(0) and ZnO NPs and their soluble ion analogs to methanogens. PMID:26803736

  1. Ion microprobe elemental analyses of impact features on interplanetary dust experiment sensor surfaces

    NASA Technical Reports Server (NTRS)

    Simon, Charles G.; Hunter, Jerry L.; Wortman, Jim J.; Griffis, Dieter P.

    1992-01-01

    Hypervelocity impact features from very small particles (less than 3 microns in diameter) on several of the electro-active dust sensors used in the Interplanetary Dust Experiment (IDE) were subjected to elemental analysis using an ion microscope. The same analytical techniques were applied to impact and containment features on a set of ultra-pure, highly polished single crystal germanium wafer witness plates that were mounted on tray B12. Very little unambiguously identifiable impactor debris was found in the central craters or shatter zones of small impacts in this crystalline surface. The surface contamination, ubiquitous on the surface of the Long Duration Exposure Facility, has greatly complicated data collection and interpretation from microparticle impacts on all surfaces.

  2. Mathematical modeling and remote monitoring of ion-exchange separation of transplutonium elements

    SciTech Connect

    Tselishchev, I.V.; Elesin, A.A.

    1988-07-01

    A mathematical model and calculational algorithms for the elution curves for ion-exchange separation of transplutonium elements (TPE) and the limits of optimal fractionation of the substances being separated, based on indicators of the process (yield, purification), are presented. The calculational programs are part of the programming provision of a small informational-calculational system based on the microcomputer Elektronika DZ-28, intended for remote monitoring of TPE separation. The elaborated programs can be implemented in the preliminary choice of necessary conditions of the TPE separation process, and also during and after the separation process for comparison of calculated results with the results of continuous, on-line remote monitoring and with the results of laboratory sample analysis. The possible application of the programs has been checked in the instance of the separation of curium and americium, and einsteinium and californium, the results of which are in satisfactory agreement with the results of remote and laboratory-analytical monitoring.

  3. Elemental ratios and the uptake and release of nutrients by phytoplankton and bacteria in three lakes of the Canadian shield.

    PubMed

    Elser, J J; Chrzanowski, T H; Sterner, R W; Schampel, J H; Foster, D K

    1995-03-01

    The dynamics of carbon (C), nitrogen (N), and phosphorus (P), elemental ratios, and dark uptake/release of N and P in bacterial and phytoplankton size fractions were studied during summer 1992 in three lakes of contrasting food web structure and trophic status (L240, L110, L227). We wished to determine if phytoplankton and bacteria differed in their elemental characteristics and to evaluate whether the functional role of bacteria in nutrient cycling (i.e., as sink or source) depended on bacterial elemental characteristics. Bacterial contributions to total suspended particulate material and to fluxes of nutrients in the dark were substantial and varied for different elements. This indicated that some techniques for assaying phytoplankton physiological condition are compromised by bacterial contributions. C/N ratios were generally less variable than C/P and N/P ratios. Both elemental ratios and biomass-normalized N and P flux indicated that phytoplankton growth in each lake was predominantly P-limited, although in L227 these data reflect the dominance of N-fixing cyanobacteria, and N was likely limiting early in the sampling season. In L227, phytoplankton N/P ratio and biomass-normalized N flux were negatively correlated, indicating that flux data were likely a reasonable measure of the N status of the phytoplankton. However, for L227 phytoplankton, P-flux per unit biomass was a hyperbolic function of N/P, suggesting that the dominant L227 cyanobacteria have a limited uptake and storage capacity and that P-flux per unit biomass may not be a good gauge of the P-limitation status of phytoplankton in this situation. Examination of N-flux data in the bacterial size fraction relative to the N/P ratio of the bacteria revealed a threshold N/P ratio (∼22:1 N/P, by atoms), below which, bacteria took up and sequestered added N, and above which, N was released. Thus, the functional role of bacteria in N cycling in these ecosystems depended on their N/P stoichiometry. PMID

  4. Inhibition of trace element release during Fe(II)-activated recrystallization of Al-, Cr-, and Sn-substituted goethite and hematite

    SciTech Connect

    Frierdich, Andrew J.; Scherer, M.; Bachman, Jonathan E.; Engelhard, Mark H.; Rapponotti, Brett W.; Catalano, Jeffrey G.

    2012-09-18

    Aqueous Fe(II) reacts with Fe(III) oxides by coupled electron transfer and atom exchange (ETAE) resulting in mineral recrystallization, contaminant reduction, and trace element cycling. Previous studies of Fe(II)-Fe(III) ETAE have explored the reactivity of either pure iron oxide phases or those containing small quantities of soluble trace elements. Naturally occurring iron oxides, however, contain substantial quantities of insoluble impurities (e.g., Al) which are known to affect the chemical properties of such minerals. Here we explore the effect of Al(III), Cr(III), and Sn(IV) substitution on trace element release from Ni(II)-substituted goethite and Zn(II)-substituted hematite during reaction with aqueous Fe(II). Fe(II)-activated trace element release is substantially inhibited from both minerals when an insoluble element is co-substituted into the structure, and the total amount of release decreases exponentially with increasing co substituent. The limited changes in surface composition that occur following reaction with Fe(II) indicate that Al, Cr, and Sn do not exsolve from the structure and that Ni and Zn released to solution originate primarily from the bulk rather than the particle exterior (upper ~3 nm). Incorporation of Al into goethite substantially decreases the amount of iron atom exchange with aqueous Fe(II) and, consequently, the amount of Ni release from the structure. This implies that trace element release inhibition caused by substituting insoluble elements results from a decrease in the amount of mineral recrystallization. These results suggest that naturally occurring iron oxides containing insoluble elements are less susceptible to Fe(II)-activated recrystallization and exhibit a greater retention of trace elements and contaminants than pure mineral phases.

  5. Inhibition of trace element release during Fe(II)-activated recrystallization of Al-, Cr-, and Sn-substituted goethite and hematite.

    PubMed

    Frierdich, Andrew J; Scherer, Michelle M; Bachman, Jonathan E; Engelhard, Mark H; Rapponotti, Brett W; Catalano, Jeffrey G

    2012-09-18

    Aqueous Fe(II) reacts with Fe(III) oxides by coupled electron transfer and atom exchange (ETAE) resulting in mineral recrystallization, contaminant reduction, and trace element cycling. Previous studies of Fe(II)-Fe(III) ETAE have explored the reactivity of either pure iron oxide phases or those containing small quantities of soluble trace elements. Naturally occurring iron oxides, however, contain substantial quantities of insoluble impurities (e.g., Al) which are known to affect the chemical properties of such minerals. Here we explore the effect of Al(III), Cr(III), and Sn(IV) substitution (1-8 mol %) on trace element release from Ni(II)-substituted goethite and Zn(II)-substituted hematite during reaction with aqueous Fe(II). Fe(II)-activated trace element release is substantially inhibited from both minerals when an insoluble element is cosubstituted into the structure, and the total amount of release decreases exponentially with increasing cosubstituent. The limited changes in surface composition that occur following reaction with Fe(II) indicate that Al, Cr, and Sn do not exsolve from the structure and that Ni and Zn released to solution originate primarily from the bulk rather than the particle exterior (upper ~3 nm). Incorporation of Al into goethite substantially decreases the amount of iron atom exchange with aqueous Fe(II) and, consequently, the amount of Ni release from the structure. This implies that trace element release inhibition caused by substituting insoluble elements results from a decrease in the amount of mineral recrystallization. These results suggest that naturally occurring iron oxides containing insoluble elements are less susceptible to Fe(II)-activated recrystallization and exhibit a greater retention of trace elements and contaminants than pure mineral phases. PMID:22924460

  6. Generation of intense and cold beam of Pt-Ag bi-element cluster ions having single-composition

    NASA Astrophysics Data System (ADS)

    Yasumatsu, H.

    2011-07-01

    An intense beam of bi-element Pt-Ag cluster ions with a single atomic-composition has been gained toward development of new-functional materials of the clusters fixed on a solid surface. Mass production of the bi-element cluster ions has been achieved by operating dual magnetron-sputtering devices independently in a gas aggregation cell, and the ions having a single composition are filtered out by passing through a quadrupole mass filter. The kinetic energies of the cluster ions have been reduced by collision with cold helium in order for low-energy cluster-impact deposition of the clusters on the surface. The cooling process was examined further by means of molecular-dynamics simulation.

  7. Oral sustained-release suspension based on a novel taste-masked and mucoadhesive carrier-ion-exchange fiber.

    PubMed

    Yuan, Jing; Liu, Tiaotiao; Li, Heran; Shi, Tianyu; Xu, Jie; Liu, Hongzhuo; Wang, Zhiguo; Wang, Qifang; Xu, Lu; Wang, Yan; Li, Sanming

    2014-09-10

    The purpose of this study was to evaluate the feasibility of ion-exchange fiber ZB-1 as a novel carrier in oral taste-masked mucoadhesive sustained-release suspensions. Propranolol (PPN) hydrochloride was selected as a model drug with good water solubility, short half life and bitter taste. The PPN-fiber complexes (PF) were prepared by a batch process and coated with Eudragit(®) RS100. Gamma scintigraphy was performed on fasted volunteers revealed about 30% ZB-1 and more than 50% coated ZB-1 were still remaining in the stomach at 6h. In vitro results showed the releases of PF and coated PPN-fiber complexes (C-PF) were sustained. The release, drug content and particle size of C-PF were influenced by coat to core ratio, concentration of coating material and rotation rate. The suspension was stable after standing for 30 days in 0.5% Carbopol(®) with no release rate and taste changed. The administration of C-PF suspension to rats resulted a significant different (P<0.05) improvement of the plasma drug level and prolongation of the release. However, because of the burst effect, the Cmax values of PF suspension didn't differ from drug solution (P>0.05). Furthermore, a linear relationship between in vitro dissolution and in vivo absorption was observed. PMID:24882038

  8. Mechanical behavior of representative volume elements of lithium-ion battery modules under various loading conditions

    NASA Astrophysics Data System (ADS)

    Lai, Wei-Jen; Ali, Mohammed Yusuf; Pan, Jwo

    2014-02-01

    Mechanical behavior of lithium-ion battery modules is investigated by conducting tensile tests of the module components, constrained compression tests of dry module representative volume element (RVE) specimens, and a constrained punch test of a small-scale dry module specimen. The results of tensile tests of the module components are used to characterize the tensile behavior of module specimens. The results in-plane constrained compression tests of module RVE specimens indicate that the load carrying capacity is characterized by the buckling of the module components and the final densification of the module components, and the nominal stress-strain curves appear to be independent of the specimen height. The results of different compressive nominal stress-strain curves in the in-plane and out-of-plane directions indicate the module RVE specimens are anisotropic. The results of a buckling analysis of the module RVE specimens under in-plane constrained compression are in agreement with the experimental results. The module RVE specimen is dominated by the buckling of the aluminum heat dissipater sheet under in-plane constrained compression. Finally, the results of a constrained punch test of a module specimen are in agreement with those of the corresponding finite element analyses based on a macroscopic homogenized foam material model.

  9. Determination of trace element mineral/liquid partition coefficients in melilite and diopside by ion and electron microprobe techniques

    NASA Technical Reports Server (NTRS)

    Kuehner, S. M.; Laughlin, J. R.; Grossman, L.; Johnson, M. L.; Burnett, D. S.

    1989-01-01

    The applicability of ion microprobe (IMP) for quantitative analysis of minor elements (Sr, Y, Zr, La, Sm, and Yb) in the major phases present in natural Ca-, Al-rich inclusions (CAIs) was investigated by comparing IMP results with those of an electron microprobe (EMP). Results on three trace-element-doped glasses indicated that it is not possible to obtain precise quantitative analysis by using IMP if there are large differences in SiO2 content between the standards used to derive the ion yields and the unknowns.

  10. Mineralogy and the release of trace elements from slag from the Hegeler Zinc smelter, Illinois (USA)

    USGS Publications Warehouse

    Piatak, N.M.; Seal, R.R., II

    2010-01-01

    Slag from the former Hegeler Zn-smelting facility in Illinois (USA) is mainly composed of spinifex Ca-rich plagioclase, fine-grained dendritic or coarse-grained subhedral to anhedral clinopyroxenes, euhedral to subhedral spinels, spherical blebs of Fe sulfides, silicate glass, and less commonly fayalitic olivine. Mullite and quartz were also identified in one sample as representing remnants of the furnace lining. Secondary phases such as goethite, hematite and gypsum are significant in some samples and reflect surficial weathering of the dump piles or represent byproducts of roasting. A relatively rare Zn-rich material contains anhedral willemite, subhedral gahnite, massive zincite, hardystonite and a Zn sulfate (brianyoungite), among other phases, and likely represents the molten content of the smelting furnace before Zn extraction. The bulk major-element chemistry of most slag samples is dominated by SiO2, Al2O3, Fe2O3 and CaO. The bulk composition of the slag suggests a high viscosity of the melt and the mineralogy suggests a high silica content of the melt. Bulk slag trace-element chemistry shows that the dominant metal is Zn with >28.4 wt.% in the Zn-rich material and between 212 and 14,900 mg/kg in the other slags. The concentrations of other trace elements reach the following: 45 mg/kg As, 1170 mg/kg Ba, 191 mg/kg Cd, 242 mg/kg Co, 103 mg/kg Cr, 6360 mg/kg Cu, 107 mg/kg Ni, and 711 mg/kg Pb. Zinc, as the dominant metal in the slags, is likely the most environmentally significant metal in these samples; Cd, Cu, and Pb are also of concern and their concentrations exceed US Environmental Protection Agency preliminary remediation goals for residential soils. Spinel was found to be the dominant concentrator of Zn for samples containing significant Zn (>1 wt.%); the silicate glass also contained relatively high concentrations of Zn compared to other phases. Zinc partitioned into the silicates and oxides in these samples is generally more resistant to weathering

  11. A Study on Removal of Rare Earth Elements from U.S. Coal Byproducts by Ion Exchange

    NASA Astrophysics Data System (ADS)

    Rozelle, Peter L.; Khadilkar, Aditi B.; Pulati, Nuerxida; Soundarrajan, Nari; Klima, Mark S.; Mosser, Morgan M.; Miller, Charles E.; Pisupati, Sarma V.

    2016-03-01

    Rare earth elements are known to occur in low concentrations in U.S. coals and coal byproducts. These low concentrations may make rare earth element recovery from these materials unattractive, using only physical separation techniques. However, given the significant production of rare earths through ion exchange extraction in China, two U.S. coal byproducts were examined for ion extraction, using ammonium sulfate, an ionic liquid, and a deep eutectic solvent as lixiviants. Extraction of rare earth elements in each case produced high recoveries of rare earth elements to the solution. This suggests that in at least the cases of the materials examined, U.S. coal byproducts may be technically suitable as REE ores. More work is required to establish economic suitability.

  12. Template copolymerization to control site structure around metal ions: Applications towards sensing and gas storage and release

    NASA Astrophysics Data System (ADS)

    Mitchell-Koch, Jeremy T.

    The development of functional materials for sensing and gas storage and release is useful in a number of chemical and biological applications. Investigating function of molecularly imprinted polymers (MIP), often used for these purposes, has relied on circumstantial evidence because direct examination of immobilized sites is not possible. Described in this dissertation is the design, synthesis, characterization and function studies of materials synthesized by template copolymerization methods. Metal ions exhibit unique spectroscopic properties and their utilization makes site examination more feasible. Ligand binding modulates these properties such that the event can be measured by spectroscopy. The metal ion's secondary coordination environment can also be tuned to increase or decrease function of the material. In Chapter Two the utilization of template copolymerization to immobilize a europium-containing compound for the detection of volatile organic compounds is described. Luminescence of the immobilized complex is quenched in the presence of volatile organic compounds (VOC). The quenching effect is dependent on concentration of VOC and the nature of polymeric host. Chapters Three and Four describe the development of materials for the photolytic release of nitric oxide (NO). In Chapter Three, a novel manipulation of the immobilized complex is employed to produce binding sites that contain ligands covalently embedded into the host in a position to bind the metal ion upon NO release in order to block rebinding. Incompatible binding affinities of the iron-containing templates made it impossible to study NO photo-release from this material. Second-row transition metals are more compatible with NO binding, and Chapter Four describes a ruthenium salen-containing polymer that releases NO in response to light. Additionally, transfer of NO to a metalloporphyrin and myoglobin has been achieved. This is the first report of photolytic heterogeneous NO transfer by a material

  13. Impact of rice cultivar and organ on elemental composition of phytoliths and the release of bio-available silicon

    PubMed Central

    Li, Zimin; Song, Zhaoliang; Cornelis, Jean-Thomas

    2014-01-01

    The continental bio-cycling of silicon (Si) plays a key role in global Si cycle and as such partly controls global carbon (C) budget through nutrition of marine and terrestrial biota, accumulation of phytolith-occluded organic carbon (PhytOC) and weathering of silicate minerals. Despite the key role of elemental composition of phytoliths on their solubility in soils, the impact of plant cultivar and organ on the elemental composition of phytoliths in Si high-accumulator plants, such as rice (Oryza sativa) is not yet fully understood. Here we show that rice cultivar significantly impacts the elemental composition of phytoliths (Si, Al, Fe, and C) in different organs of the shoot system (grains, sheath, leaf and stem). The amount of occluded OC within phytoliths is affected by contents of Si, Al, and Fe in plants, while independent of the element composition of phytoliths. Our data document, for different cultivars, higher bio-available Si release from phytoliths of leaves and sheaths, which are characterized by higher enrichment with Al and Fe (i.e., lower Si/Al and Si/Fe ratios), compared to grains and stems. We indicate that phytolith solubility in soils may be controlled by rice cultivar and type of organs. Our results highlight that the role of the morphology, the hydration rate and the chemical composition in the solubility of phytoliths and the kinetic release of Si in soil solution needs to be studied further. This is central to a better understanding of the impact of soil amendment with different plant organs and cultivars on soil OC stock and on the delivery of dissolved Si as we show that sheath and leaf rice organs are both characterized by higher content of OC occluded in phytolith and higher phytolith solubility compared to grains and stems. Our study shows the importance of studying the impact of the agro-management on the evolution of sinks and sources of Si and C in soils used for Si-high accumulator plants. PMID:25346741

  14. Impact of rice cultivar and organ on elemental composition of phytoliths and the release of bio-available silicon.

    PubMed

    Li, Zimin; Song, Zhaoliang; Cornelis, Jean-Thomas

    2014-01-01

    The continental bio-cycling of silicon (Si) plays a key role in global Si cycle and as such partly controls global carbon (C) budget through nutrition of marine and terrestrial biota, accumulation of phytolith-occluded organic carbon (PhytOC) and weathering of silicate minerals. Despite the key role of elemental composition of phytoliths on their solubility in soils, the impact of plant cultivar and organ on the elemental composition of phytoliths in Si high-accumulator plants, such as rice (Oryza sativa) is not yet fully understood. Here we show that rice cultivar significantly impacts the elemental composition of phytoliths (Si, Al, Fe, and C) in different organs of the shoot system (grains, sheath, leaf and stem). The amount of occluded OC within phytoliths is affected by contents of Si, Al, and Fe in plants, while independent of the element composition of phytoliths. Our data document, for different cultivars, higher bio-available Si release from phytoliths of leaves and sheaths, which are characterized by higher enrichment with Al and Fe (i.e., lower Si/Al and Si/Fe ratios), compared to grains and stems. We indicate that phytolith solubility in soils may be controlled by rice cultivar and type of organs. Our results highlight that the role of the morphology, the hydration rate and the chemical composition in the solubility of phytoliths and the kinetic release of Si in soil solution needs to be studied further. This is central to a better understanding of the impact of soil amendment with different plant organs and cultivars on soil OC stock and on the delivery of dissolved Si as we show that sheath and leaf rice organs are both characterized by higher content of OC occluded in phytolith and higher phytolith solubility compared to grains and stems. Our study shows the importance of studying the impact of the agro-management on the evolution of sinks and sources of Si and C in soils used for Si-high accumulator plants. PMID:25346741

  15. Surface properties and ion release from fluoride-containing bioactive glasses promote osteoblast differentiation and mineralization in vitro.

    PubMed

    Gentleman, E; Stevens, M M; Hill, R G; Brauer, D S

    2013-03-01

    Bioactive glasses (BG) are suitable for bone regeneration applications as they bond with bone and can be tailored to release therapeutic ions. Fluoride, which is widely recognized to prevent dental caries, is efficacious in promoting bone formation and preventing osteoporosis-related fractures when administered at appropriate doses. To take advantage of these properties, we created BG incorporating increasing levels of fluoride whilst holding their silicate structure constant, and tested their effects on human osteoblasts in vitro. Our results demonstrate that, whilst cell proliferation was highest on low-fluoride-containing BG, markers for differentiation and mineralization were highest on BG with the highest fluoride contents, a likely effect of a combination of surface effects and ion release. Furthermore, osteoblasts exposed to the dissolution products of fluoride-containing BG or early doses of sodium fluoride showed increased alkaline phosphatase activity, a marker for bone mineralization, suggesting that fluoride can direct osteoblast differentiation. Taken together, these results suggest that BG that can release therapeutic levels of fluoride may find use in a range of bone regeneration applications. PMID:23128161

  16. Avidin-biotin capped mesoporous silica nanoparticles as an ion-responsive release system to determine lead(II).

    PubMed

    Song, Weiling; Li, Jingyu; Li, Qing; Ding, Wenyao; Yang, Xiaoyan

    2015-02-15

    We have developed DNAzyme-functionalized silica nanoparticles for the rapid, sensitive, and selective detection of lead ion (Pb(2+)). The specific binding between avidin and biotinylated DNAzymes was used to cap the pore of dye-trapped silica nanoparticles. In the presence of Pb(2+), DNAzymes were catalytically cleaved to uncap the pore, releasing the dye cargo with detectable enhancements of fluorescence signal. This method enables rapid (15 min) and sensitive (limit of detection=8.0 nM) detection. Moreover, the Pb(2+)-responsive behavior shows high selectivity with other metal ions. The superior properties of the as-designed DNAzyme-functionalized silica nanoparticles can be attributed to the large loading capacity and highly ordered pore structure of mesoporous silica nanoparticles as well as the catalytical cleaving of DNAzymes with Pb(2+). The recoveries obtained by standard Pb(II) addition to real samples-tap water, commercial mineral water, and lake water-were all from 98 to 101%. Our design serves as a new prototype for metal-ion sensing systems, and it also has promising potential for detection of various targets in stimulus-release systems. PMID:25447495

  17. Kinetic-energy release in the dissociative capture-ionization of CO molecules by 97-MeV Ar14+ ions

    NASA Astrophysics Data System (ADS)

    Watson, R. L.; Sampoll, G.; Horvat, V.; Heber, O.

    1996-02-01

    The dissociation of COQ+ molecular ions (Q=4 to 9) produced in multiply ionizing collisions accompanied by the transfer of an electron to the projectile has been studied using time-of-flight techniques. Analysis of the coincident-ion-pair flight-time-difference distributions yielded average values of the kinetic-energy releases for the various dissociation reactions. These values were found to be as much as a factor of 2 greater than the kinetic-energy releases expected for dissociation along Coulombic potential curves. The average kinetic-energy release observed for a given ion pair with charges q1 and q2 are nearly equal to the point-charge Coulomb potential energies for an ion pair with charges q1+1 and q2+1, suggesting that the parent molecular ion is formed with two electrons, on average, in highly excited states that do not contribute to the screening of the nuclei.

  18. Nitric acid passivation of Ti6Al4V reduces thickness of surface oxide layer and increases trace element release.

    PubMed

    Callen, B W; Lowenberg, B F; Lugowski, S; Sodhi, R N; Davies, J E

    1995-03-01

    Passivation of Ti6Al4V and cpTi implants using methods based on the ASTM-F86 nitric acid protocol are used with the intention of reducing their surface reactivity, and consequently the corrosion potential, in the highly corrosive biologic milieu. The ASTM-F86 passivation protocol was originally developed for surgical implants made of stainless steel and chrome cobalt alloy. Using X-ray photoelectron spectroscopy (XPS) to examine the effect of nitric acid passivation on the surface oxide layer of mill-annealed Ti6Al4V and cpTi, we have found that such treatment actually reduced the oxide thickness on the alloy while having no significant effect on the pure metal. These results correlated with observations obtained using graphite furnace atomic absorption spectrophotometry (GFAAS) to detect trace element release from solid, mill-annealed, Ti6Al4V and cpTi into serum-containing culture medium. We detected significantly greater levels of Ti, Al, and V in the presence of passivated compared to nonpassivated Ti6Al4V. In contrast, nitric acid passivation did not influence Ti release from mill-annealed cpTi. These results, derived from two mill-annealed Ti-based metals, would indicate that re-examination of ASTM-F86-based passivation protocols with respect to Ti6Al4V should be considered in view of the widespread use of this alloy for biomedical devices. PMID:7615579

  19. Specific release of membrane-bound annexin II and cortical cytoskeletal elements by sequestration of membrane cholesterol.

    PubMed Central

    Harder, T; Kellner, R; Parton, R G; Gruenberg, J

    1997-01-01

    Annexin II is an abundant protein which is present in the cytosol and on the cytoplasmic face of plasma membrane and early endosomes. It is generally believed that this association occurs via Ca(2+)-dependent binding to lipids, a mechanism typical for the annexin protein family. Although previous studies have shown that annexin II is involved in early endosome dynamics and organization, the precise biological role of the protein is unknown. In this study, we found that approximately 50% of the total cellular annexin was associated with membranes in a Ca(2+)-independent manner. This binding was extremely tight, since it resisted high salt and, to some extent, high pH treatments. We found, however, that membrane-associated annexin II could be quantitatively released by low concentrations of the cholesterol-sequestering agents filipin and digitonin. Both treatments released an identical and limited set of proteins but had no effects on other membrane-associated proteins. Among the released proteins, we identified, in addition to annexin II itself, the cortical cytoskeletal proteins alpha-actinin, ezrin and moesin, and membrane-associated actin. Our biochemical and immunological observations indicate that these proteins are part of a complex containing annexin II and that stability of the complex is sensitive to cholesterol sequestering agents. Since annexin II is tightly membrane-associated in a cholesterol-dependent manner, and since it seems to interact physically with elements of the cortical actin cytoskeleton, we propose that the protein serves as interface between membranes containing high amounts of cholesterol and the actin cytoskeleton. Images PMID:9188103

  20. Localization of CdSe/ZnS quantum dots in the lysosomal acidic compartment of cultured neurons and its impact on viability: potential role of ion release.

    PubMed

    Corazzari, Ingrid; Gilardino, Alessandra; Dalmazzo, Simona; Fubini, Bice; Lovisolo, Davide

    2013-03-01

    CdSe Quantum Dots (QDs) are increasingly being employed in both industrial applications and biological imaging, thanks to their numerous advantages over conventional organic and proteic fluorescent markers. On the other hand a growing concern has emerged that toxic elements from the QDs core would render the nanoparticles harmful to cell cultures, animals and humans. The interaction between QDs and neuronal cells in particular needs to be carefully evaluated, since nanoparticles could access the nervous system by several pathways, including the olfactory epithelium, even if no data are presently available about QDs. The pH of the environment to which the nanoparticles are exposed may play a crucial role in the stability of QDs coating. For this reason we investigated the release of metal ions from CdSe/ZnS QDs in artificial media reproducing the cytosolic and lysosomal cellular compartments characterized respectively by a neutral and an acidic pH. In the latter significant amounts of both Cd(2+) and Zn(2+) were released. We provide evidence that these QDs are internalized in the GT1-7 neuronal cell line and located in the lysosomal compartment. These findings can be related to a slight but significant reduction in cell survival and proliferation. PMID:23274769

  1. Gellan gum microspheres crosslinked with trivalent ion: effect of polymer and crosslinker concentrations on drug release and mucoadhesive properties.

    PubMed

    Boni, Fernanda Isadora; Prezotti, Fabíola Garavello; Cury, Beatriz Stringhetti Ferreira

    2016-08-01

    Gellan gum microspheres were obtained by ionotropic gelation technique, using the trivalent ion Al(3+). The percentage of entrapment efficiency ranged from 48.76 to 87.52% and 2(2) randomized full factorial design demonstrated that both the increase of polymer concentration and the decrease of crosslinker concentration presented a positive effect in the amount of encapsulated drug. Microspheres size and circularity ranged from 700.17 to 938.32 μm and from 0.641 to 0.796 μm, respectively. The increase of polymer concentration (1-2%) and crosslinker concentration (3-5%) led to the enlargement of particle size and circularity. However, the association of increased crosslinker concentration and reduced polymer content made the particles more irregular. In vitro and ex vivo tests evidenced the high mucoadhesiveness of microspheres. The high liquid uptake ability of the microspheres was demonstrated and the pH variation did not affect this parameter. Drug release was pH dependent, with low release rates in acid pH (42.40% and 44.93%) and a burst effect in phosphate buffer pH (7.4). The Weibull model had the best correlation with the drug release data, demonstrating that the release process was driven by a complex mechanism involving the erosion and swelling of the matrix or by non-Fickian diffusion. PMID:26616390

  2. Evaluation of effect of galvanic corrosion between nickel-chromium metal and titanium on ion release and cell toxicity

    PubMed Central

    Choi, Jung-Yun

    2015-01-01

    PURPOSE The purpose of this study was to evaluate cell toxicity due to ion release caused by galvanic corrosion as a result of contact between base metal and titanium. MATERIALS AND METHODS It was hypothesized that Nickel (Ni)-Chromium (Cr) alloys with different compositions possess different corrosion resistances when contacted with titanium abutment, and therefore in this study, specimens (10×10×1.5 mm) were fabricated using commercial pure titanium and 3 different types of Ni-Cr alloys (T3, Tilite, Bella bond plus) commonly used for metal ceramic restorations. The specimens were divided into 6 groups according to the composition of Ni-Cr alloy and contact with titanium. The experimental groups were in direct contact with titanium and the control groups were not. After the samples were immersed in the culture medium - Dulbecco's modified Eagle's medium[DMEM] for 48 hours, the released metal ions were detected using inductively coupled plasma mass spectrometer (ICP-MS) and analyzed by the Kruskal-Wallis and Mann-Whitney test (P<.05). Mouse L-929 fibroblast cells were used for cell toxicity evaluation. The cell toxicity of specimens was measured by the 3-{4,5-dimethylthiazol-2yl}-2,5-diphenyltetrazolium bromide (MTT) test. Results of MTT assay were statistically analyzed by the two-way ANOVA test (P<.05). Post-hoc multiple comparisons were conducted using Tukey's tests. RESULTS The amount of metal ions released by galvanic corrosion due to contact between the base metal alloy and titanium was increased in all of the specimens. In the cytotoxicity test, the two-way ANOVA showed a significant effect of the alloy type and galvanic corrosion for cytotoxicity (P<.001). The relative cell growth rate (RGR) was decreased further on the groups in contact with titanium (P<.05). CONCLUSION The release of metal ions was increased by galvanic corrosion due to contact between base metal and titanium, and it can cause adverse effects on the tissue around the implant by inducing

  3. Quantum ricochets: surface capture, release and energy loss of fast ions hitting a polar surface at grazing incidence

    NASA Astrophysics Data System (ADS)

    Lucas, A. A.; Sunjic, M.; Benedek, G.; Echenique, P. M.

    2014-06-01

    A diffraction mechanism is proposed for the capture, multiple bouncing and final escape of a fast ion (keV) impinging on the surface of a polarizable material at grazing incidence. Capture and escape are effected by elastic quantum diffraction consisting of the exchange of a parallel surface wave vector G = 2π/a between the ion parallel momentum and the surface periodic potential of period a. Diffraction-assisted capture becomes possible for glancing angles Φ smaller than a critical value given by Φ c2 ≈ 2λ/a-|V im|/E, where E is the kinetic energy of the ion, λ = h/Mv its de Broglie wavelength and V im its average electronic image potential at the distance from the surface where diffraction takes place. For Φ < Φ c, the ion can fall into a selected capture state in the quasi-continuous spectrum of its image potential and execute one or several ricochets before being released by the time reversed diffraction process. The capture, ricochet and escape are accompanied by a large, periodic energy loss of several tens of eV in the forward motion caused by the coherent emission of a giant number of quanta ħω of Fuchs-Kliewer surface phonons characteristic of the polar material. An analytical calculation of the energy loss spectrum, based on the proposed diffraction process and using a model ion-phonon coupling developed earlier (Lucas et al 2013 J. Phys.: Condens. Matter 25 355009), is presented, which fully explains the experimental spectrum of Villette et al (2000 Phys. Rev. Lett. 85 3137) for Ne+ ions ricocheting on a LiF(001) surface.

  4. Utilizing environmental friendly iron as a substitution element in spinel structured cathode materials for safer high energy lithium-ion batteries

    DOE PAGESBeta

    Hu, Enyuan; Bak, Seong -Min; Liu, Yijin; Liu, Jue; Yu, Xiqian; Zhou, Yong -Ning; Zhou, Jigang; Khalifah, Peter; Ariyoshi, Kingo; Nam, Kyung -Wan; et al

    2015-12-03

    Suppressing oxygen release from lithium ion battery cathodes during heating is a critical issue for the improvement of the battery safety characteristics because oxygen can exothermically react with the flammable electrolyte and cause thermal runaway. Previous studies have shown that oxygen release can be reduced by the migration of transition metal cations from octahedral sites to tetrahedral sites during heating. Such site-preferred migration is determined by the electronic structure of cations. In addition, taking advantage of the unique electronic structure of the environmental friendly Fe, this is selected as substitution element in a high energy density material LiNi0.5Mn1.5O4 to improvemore » the thermal stability. The optimized LiNi0.33Mn1.33Fe0.33O4 material shows significantly improved thermal stability compared with the unsubstituted one, demonstrated by no observed oxygen release at temperatures as high as 500°C. Due to the electrochemical contribution of Fe, the high energy density feature of LiNi0.5Mn1.5O4 is well preserved.« less

  5. Utilizing environmental friendly iron as a substitution element in spinel structured cathode materials for safer high energy lithium-ion batteries

    SciTech Connect

    Hu, Enyuan; Bak, Seong -Min; Liu, Yijin; Liu, Jue; Yu, Xiqian; Zhou, Yong -Ning; Zhou, Jigang; Khalifah, Peter; Ariyoshi, Kingo; Nam, Kyung -Wan; Yang, Xiao -Qing

    2015-12-03

    Suppressing oxygen release from lithium ion battery cathodes during heating is a critical issue for the improvement of the battery safety characteristics because oxygen can exothermically react with the flammable electrolyte and cause thermal runaway. Previous studies have shown that oxygen release can be reduced by the migration of transition metal cations from octahedral sites to tetrahedral sites during heating. Such site-preferred migration is determined by the electronic structure of cations. In addition, taking advantage of the unique electronic structure of the environmental friendly Fe, this is selected as substitution element in a high energy density material LiNi0.5Mn1.5O4 to improve the thermal stability. The optimized LiNi0.33Mn1.33Fe0.33O4 material shows significantly improved thermal stability compared with the unsubstituted one, demonstrated by no observed oxygen release at temperatures as high as 500°C. Due to the electrochemical contribution of Fe, the high energy density feature of LiNi0.5Mn1.5O4 is well preserved.

  6. Nickel Ion Release from Three Types of Nickel-titanium-based Orthodontic Archwires in the As-received State and After Oral Simulation

    PubMed Central

    Ramazanzadeh, Barat Ali; Ahrari, Farzaneh; Sabzevari, Berahman; Habibi, Samaneh

    2014-01-01

    Background and aims. This study aimed to investigate release of nickel ion from three types of nickel-titanium-based wires in the as-received state and after immersion in a simulated oral environment. Materials and methods. Forty specimens from each of the single-strand NiTi (Rematitan "Lite"), multi-strand NiTi (SPEED Supercable) and Copper NiTi (Damon Copper NiTi) were selected. Twenty specimens from each type were used in the as-received state and the others were kept in deflected state at 37ºC for 2 months followed by autoclave sterilization. The as-received and recycled wire specimens were immersed in glass bottles containing 1.8 mL of artificial saliva for 28 days and the amount of nickel ion released into the electrolyte was determined using atomic absorption spectrophotometry. Results. The single-strand NiTi released the highest quantity of nickel ion in the as-received state and the multi-strand NiTi showed the highest ion release after oral simulation. The quantity of nickelion released from Damon Copper NiTi was the lowest in both conditions. Oral simulation followed by sterilization did not have a significant influence on nickel ion release from multi-strand NiTi and Damon Copper NiTi wires, but single-strand NiTi released statistically lower quantities of nickel ion after oral simulation. Conclusion. The multi-strand nature of Supercable did not enhance the potential of corrosion after immersion in the simulated oral environment. In vitro use of nickel-titanium-based archwires followed by sterilization did not significantly increase the amount of nickel ion released from these wires. PMID:25093049

  7. Objective assessment of an ionic footbath (IonCleanse): testing its ability to remove potentially toxic elements from the body.

    PubMed

    Kennedy, Deborah A; Cooley, Kieran; Einarson, Thomas R; Seely, Dugald

    2012-01-01

    Ionic footbaths are often used in holistic health centres and spas to aid in detoxification; however, claims that these machines eliminate toxins from the body have not been rigorously evaluated. In this proof-of-principle study, we sought to measure the release of potentially toxic elements from ionic footbaths into distilled and tap water with and without feet. Water samples were collected and analyzed following 30-minute ionic footbath sessions without feet using both distilled (n = 1) and tap water (n = 6) and following four ionic footbaths using tap water (once/week for 4 weeks) in six healthy participants. Urine collection samples were analyzed at four points during the study. Hair samples were analyzed for element concentrations at baseline and study conclusion. Contrary to claims made for the machine, there does not appear to be any specific induction of toxic element release through the feet when running the machine according to specifications. PMID:22174728

  8. Prospects for laser spectroscopy, ion chemistry and mobility measurements of superheavy elements in buffer-gas traps

    NASA Astrophysics Data System (ADS)

    Backe, H.; Lauth, W.; Block, M.; Laatiaoui, M.

    2015-12-01

    Laser spectroscopic methods are reviewed which are of potential interest for the investigation of atomic and ionic level structures of superheavy elements. The latter are defined here as the trans-fermium elements with Z > 100 for which no experimental atomic or ionic level structure information is known so far, and which cannot be bred in high flux nuclear power reactors via successive neutron capture. The principles of suitable laser spectroscopic methods are described, and illustrated by examples of real experiments. The addressed methods include single-ion spectroscopy in Paul traps, laser-induced fluorescence spectroscopy (LIF), radiation-detected optical pumping (RADOP), radioactive decay-detected resonance ionization spectroscopy (RADRIS), and ion-guide-detected resonance ionization spectroscopy (IGRIS). With the exception of the first all take advantage of a storage of the ions or atoms in so-called buffer-gas traps. The developed experimental methods can, in principle, also be employed for studying ion-chemical reactions with gas admixtures like O2 as well as for performing ion mobility measurements. Both provide complementary information on the electronic structure of superheavy ions. First attempts on this road of research are reviewed as well.

  9. A Stabilized Finite Element Method for Modified Poisson-Nernst-Planck Equations to Determine Ion Flow Through a Nanopore

    PubMed Central

    Chaudhry, Jehanzeb Hameed; Comer, Jeffrey; Aksimentiev, Aleksei; Olson, Luke N.

    2013-01-01

    The conventional Poisson-Nernst-Planck equations do not account for the finite size of ions explicitly. This leads to solutions featuring unrealistically high ionic concentrations in the regions subject to external potentials, in particular, near highly charged surfaces. A modified form of the Poisson-Nernst-Planck equations accounts for steric effects and results in solutions with finite ion concentrations. Here, we evaluate numerical methods for solving the modified Poisson-Nernst-Planck equations by modeling electric field-driven transport of ions through a nanopore. We describe a novel, robust finite element solver that combines the applications of the Newton's method to the nonlinear Galerkin form of the equations, augmented with stabilization terms to appropriately handle the drift-diffusion processes. To make direct comparison with particle-based simulations possible, our method is specifically designed to produce solutions under periodic boundary conditions and to conserve the number of ions in the solution domain. We test our finite element solver on a set of challenging numerical experiments that include calculations of the ion distribution in a volume confined between two charged plates, calculations of the ionic current though a nanopore subject to an external electric field, and modeling the effect of a DNA molecule on the ion concentration and nanopore current. PMID:24363784

  10. Metal Oxide Nanosensors Using Polymeric Membranes, Enzymes and Antibody Receptors as Ion and Molecular Recognition Elements

    PubMed Central

    Willander, Magnus; Khun, Kimleang; Ibupoto, Zafar Hussain

    2014-01-01

    The concept of recognition and biofunctionality has attracted increasing interest in the fields of chemistry and material sciences. Advances in the field of nanotechnology for the synthesis of desired metal oxide nanostructures have provided a solid platform for the integration of nanoelectronic devices. These nanoelectronics-based devices have the ability to recognize molecular species of living organisms, and they have created the possibility for advanced chemical sensing functionalities with low limits of detection in the nanomolar range. In this review, various metal oxides, such as ZnO-, CuO-, and NiO-based nanosensors, are described using different methods (receptors) of functionalization for molecular and ion recognition. These functionalized metal oxide surfaces with a specific receptor involve either a complex formation between the receptor and the analyte or an electrostatic interaction during the chemical sensing of analytes. Metal oxide nanostructures are considered revolutionary nanomaterials that have a specific surface for the immobilization of biomolecules with much needed orientation, good conformation and enhanced biological activity which further improve the sensing properties of nanosensors. Metal oxide nanostructures are associated with certain unique optical, electrical and molecular characteristics in addition to unique functionalities and surface charge features which shows attractive platforms for interfacing biorecognition elements with effective transducing properties for signal amplification. There is a great opportunity in the near future for metal oxide nanostructure-based miniaturization and the development of engineering sensor devices. PMID:24841244

  11. Increase in the power of lasing on atomic and ion transitions in chemical elements

    SciTech Connect

    Klimkin, V M; Sokovikov, V G

    2007-02-28

    A method for increasing the power of pulsed lasing on atomic and ion transitions in chemical elements obtained by the conversion of the UV radiation of excimer lasers in cells with metal vapours is studied. A part of UV radiation transmitted through a cell with metal vapour is used for pumping a dye solution in such a way that the cell converter with metal vapour represents a master oscillator, while the dye cell represents an amplifier. The study is performed by the example of amplification of weak spectral components of radiation from a XeCl* laser converted in mercury and barium vapours. In the amplifying stage the longitudinal pumping of the dye is used and a scheme for suppressing self-excitation is employed. It is found by selecting dyes that the alcohol solution of uranin is nearly optimal for amplification of the 546.1-nm laser line of mercury, while the best results in amplification of the 533-nm and 648.2-nm laser lines of barium were obtained by using alcohol solutions of rhodamine 6G and oxazine 17, respectively. The power of the 546.1-nm mercury line was increased by an order of magnitude, while the power of the 533-nm and 648.2-nm lines of barium - almost by a factor of twenty-five. (lasers)

  12. Trace Elements and Common Ions in Southeastern Idaho Snow: Regional Air Pollutant Tracers for Source Area Emissions

    SciTech Connect

    Abbott, Michael Lehman; Einerson, Jeffrey James; Schuster, Paul; Susong, David D.

    2002-09-01

    Snow samples were collected in southeastern Idaho over two winters to assess trace elements and common ions concentrations in air pollutant fallout across the region. The objectives were to: 1) develop sampling and analysis techniques that would produce accurate measurements of a broad suite of elements and ions in snow, 2) identify the major elements in regional fallout and their spatial and temporal trends, 3) determine if there are unique combinations of elements that are characteristic to the major source areas in the region (source profiles), and 4) use pattern recognition and multivariate statistical techniques (principal component analysis and classical least squares regression) to investigate source apportionment of the fallout to the major source areas. In the winter of 2000-2001, 250 snow samples were collected across the region over a 4-month period and analyzed in triplicate using inductively-coupled plasma mass spectrometry (ICP-MS) and ion chromatography (IC). Thirty-nine (39) trace elements and 9 common ions were positively identified in most samples. The data were analyzed using pattern recognition tools in the software, Pirouette® (Infometrix, Inc.). These results showed a large crustal component (Al, Zn, Mn, Ba, and rare earth elements), an overwhelming contribution from phosphate processing facilities located outside Pocatello in the southern portion of the ESRP, some changes in concentrations over time, and no obvious source area profiles (unique chemical signatures) other than at Pocatello. Concentrations near a major U.S. Department of Energy industrial complex on the Idaho National Engineering and Environmental Laboratory (INEEL) were lower than those observed at major downwind communities. In the winter of 2001-2002, we tried a new sampling design (and collected 135 additional samples) in an attempt to estimate pure emission profiles from the major source areas in the region and used classical least squares regression (CLS) to source

  13. On the differences in element abundances of energetic ions from corotating events and from large solar events

    NASA Technical Reports Server (NTRS)

    Reames, D. V.; Richardson, I. G.; Barbier, L. M.

    1991-01-01

    The abundances of energetic ions accelerated from high-speed solar wind streams by shock waves formed at corotating interaction regions (CIRs) where high-speed streams overtake the lower-speed solar wind are examined. The observed element abundances appear to represent those of the high-speed solar wind, unmodified by the shock acceleration. These abundances, relative to those in the solar photosphere, are organized by the first ionization potential (FIP) of the ions in a way that is different from the FIP effect commonly used to describe differences between abundances in the solar photosphere and those in the solar corona, solar energetic particles (SEPs), and the low-speed solar wind. In contrast, the FIP effect of the ion abundances in the CIR events is characterized by a smaller amplitude of the differences between high-FIP and low-FIP ions and by elevated abundances of He, C, and S.

  14. Amendment of biochar reduces the release of toxic elements under dynamic redox conditions in a contaminated floodplain soil.

    PubMed

    Rinklebe, Jörg; Shaheen, Sabry M; Frohne, Tina

    2016-01-01

    Biochar (BC) can be used to remediate soils contaminated with potential toxic elements (PTEs). However, the efficiency of BC to immobilize PTEs in highly contaminated floodplain soils under dynamic redox conditions has not been studied up to date. Thus, we have (i) quantified the impact of pre-definite redox conditions on the release dynamics of dissolved aluminum (Al), arsenic (As), cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) in a highly contaminated soil (CS) (non-treated) and in the same soil treated with 10 g kg(-1) biochar based material (CS+BC), and (ii) assessed the efficacy of the material to reduce the concentrations of PTEs in soil solution under dynamic redox conditions using an automated biogeochemical microcosm apparatus. The impact of redox potential (EH), pH, dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), iron (Fe), manganese (Mn), and sulfate (SO4(2-)) on dynamics of PTEs was also determined. The EH was lowered to +68 mV and afterwards increased stepwise to +535 mV. Significant negative correlation between EH and pH in CS and CS+BC was detected. The systematic increase of EH along with decrease of pH favors the mobilization of PTEs in CS and CS+BC. The material addition seems to have little effect on redox processes because pattern of EH/pH and release dynamics of PTEs was basically similar in CS and CS+BC. However, concentrations of dissolved PTEs were considerably lower in CS+BC than in CS which demonstrates that BC is able to decrease concentrations of dissolved PTEs even under dynamic redox conditions. PMID:25900116

  15. Quantifying element incorporation in multispecies biofilms using nanoscale secondary ion mass spectrometry image analysis.

    PubMed

    Renslow, Ryan S; Lindemann, Stephen R; Cole, Jessica K; Zhu, Zihua; Anderton, Christopher R

    2016-06-01

    Elucidating nutrient exchange in microbial communities is an important step in understanding the relationships between microbial systems and global biogeochemical cycles, but these communities are complex and the interspecies interactions that occur within them are not well understood. Phototrophic consortia are useful and relevant experimental systems to investigate such interactions as they are not only prevalent in the environment, but some are cultivable in vitro and amenable to controlled scientific experimentation. Nanoscale secondary ion mass spectrometry (NanoSIMS) is a powerful, high spatial resolution tool capable of visualizing the metabolic activities of single cells within a biofilm, but quantitative analysis of the resulting data has typically been a manual process, resulting in a task that is both laborious and susceptible to human error. Here, the authors describe the creation and application of a semiautomated image-processing pipeline that can analyze NanoSIMS-generated data, applied to phototrophic biofilms as an example. The tool employs an image analysis process, which includes both elemental and morphological segmentation, producing a final segmented image that allows for discrimination between autotrophic and heterotrophic biomass, the detection of individual cyanobacterial filaments and heterotrophic cells, the quantification of isotopic incorporation of individual heterotrophic cells, and calculation of relevant population statistics. The authors demonstrate the functionality of the tool by using it to analyze the uptake of (15)N provided as either nitrate or ammonium through the unicyanobacterial consortium UCC-O and imaged via NanoSIMS. The authors found that the degree of (15)N incorporation by individual cells was highly variable when labeled with (15)NH4 (+), but much more even when biofilms were labeled with (15)NO3 (-). In the (15)NH4 (+)-amended biofilms, the heterotrophic distribution of (15)N incorporation was highly skewed, with

  16. MinION Analysis and Reference Consortium: Phase 1 data release and analysis.

    PubMed

    Ip, Camilla L C; Loose, Matthew; Tyson, John R; de Cesare, Mariateresa; Brown, Bonnie L; Jain, Miten; Leggett, Richard M; Eccles, David A; Zalunin, Vadim; Urban, John M; Piazza, Paolo; Bowden, Rory J; Paten, Benedict; Mwaigwisya, Solomon; Batty, Elizabeth M; Simpson, Jared T; Snutch, Terrance P; Birney, Ewan; Buck, David; Goodwin, Sara; Jansen, Hans J; O'Grady, Justin; Olsen, Hugh E

    2015-01-01

    The advent of a miniaturized DNA sequencing device with a high-throughput contextual sequencing capability embodies the next generation of large scale sequencing tools. The MinION™ Access Programme (MAP) was initiated by Oxford Nanopore Technologies™ in April 2014, giving public access to their USB-attached miniature sequencing device. The MinION Analysis and Reference Consortium (MARC) was formed by a subset of MAP participants, with the aim of evaluating and providing standard protocols and reference data to the community. Envisaged as a multi-phased project, this study provides the global community with the Phase 1 data from MARC, where the reproducibility of the performance of the MinION was evaluated at multiple sites. Five laboratories on two continents generated data using a control strain of Escherichia coli K-12, preparing and sequencing samples according to a revised ONT protocol. Here, we provide the details of the protocol used, along with a preliminary analysis of the characteristics of typical runs including the consistency, rate, volume and quality of data produced. Further analysis of the Phase 1 data presented here, and additional experiments in Phase 2 of E. coli from MARC are already underway to identify ways to improve and enhance MinION performance. PMID:26834992

  17. A facility to study the particles released by ion sputtering process

    NASA Astrophysics Data System (ADS)

    de Angelis, E.; di Lellis, A. M.; Vannaroni, G.; Orsini, S.; Mangano, V.; Milillo, A.; Massetti, S.; Mura, A.; Vertolli, N.

    2007-08-01

    Research on the planetary surface erosion and planetary evolution could be enriched with the detection of the escaping material, in terms of energy and direction, caused by ions sputtering. A complete study of emitted neutral distribution from which infers the processes occurring on the impacted surface requires dedicated instrumentation, tailored on the peculiarity on the low energy profile of the sputtered signal. We propose a comprehensive facility at INAF/IFSI in Rome intended to provide the opportunity to investigate the interaction of selectable ion beam with planetary analogues through the detection of sputtered neutral atoms. The laboratory is equipped with a high volume UHV chamber, ion selectable sources in the range 0 to 10 keV, a set of 3D sample/sensor orientation motion actuation motors down to 1/100 deg resolution. The laboratory will support a set of neutral sensor heads sets derived from the Emitted for Low Energetic Neutral Atoms (ELENA) instrument under development for the ESA BepiColombo Mercury mission able to detect neutral atoms (few eV-up to 5 keV).

  18. MinION Analysis and Reference Consortium: Phase 1 data release and analysis

    PubMed Central

    Eccles, David A.; Zalunin, Vadim; Urban, John M.; Piazza, Paolo; Bowden, Rory J.; Paten, Benedict; Mwaigwisya, Solomon; Batty, Elizabeth M.; Simpson, Jared T.; Snutch, Terrance P.

    2015-01-01

    The advent of a miniaturized DNA sequencing device with a high-throughput contextual sequencing capability embodies the next generation of large scale sequencing tools. The MinION™ Access Programme (MAP) was initiated by Oxford Nanopore Technologies™ in April 2014, giving public access to their USB-attached miniature sequencing device. The MinION Analysis and Reference Consortium (MARC) was formed by a subset of MAP participants, with the aim of evaluating and providing standard protocols and reference data to the community. Envisaged as a multi-phased project, this study provides the global community with the Phase 1 data from MARC, where the reproducibility of the performance of the MinION was evaluated at multiple sites. Five laboratories on two continents generated data using a control strain of Escherichia coli K-12, preparing and sequencing samples according to a revised ONT protocol. Here, we provide the details of the protocol used, along with a preliminary analysis of the characteristics of typical runs including the consistency, rate, volume and quality of data produced. Further analysis of the Phase 1 data presented here, and additional experiments in Phase 2 of E. coli from MARC are already underway to identify ways to improve and enhance MinION performance. PMID:26834992

  19. Copper ion-mediated liposomal encapsulation of mitoxantrone: the role of anions in drug loading, retention and release.

    PubMed

    Li, Chunlei; Cui, Jingxia; Li, Yingui; Wang, Caixia; Li, Yanhui; Zhang, Lan; Zhang, Li; Guo, Wenmin; Wang, Jinxu; Zhang, Hongwu; Hao, Yanli; Wang, Yongli

    2008-08-01

    Besides pH gradient, other transmembrane gradients such as metal ion gradient could be also employed to load drugs into liposomes. In pH gradient method, anions have an important role since they could form specific aggregates with drugs, and then affect drug release kinetics from vesicles. To explore the role of anions in metal ion gradient method, copper ion-mediated mitoxantrone (MIT) loading was investigated systematically. When empty liposomes exhibiting a transmembrane copper ion gradient (300 mM) were mixed with MIT in a molar ratio of 0.2:1, after 5 min incubation at 60 degrees C, >95% MIT could be loaded into vesicles and the encapsulation was stable, regardless of the kinds of anions and initial intraliposomal pH values. The encapsulation ratio decreased with increased MIT/lipid molar ratio. But even when the molar ratio increased to 0.4, >90% encapsulation could still be achieved. In the presence of nigericin and ammonium, the drug loading profiles were affected to different degree with respect to both drug loading rate and encapsulation ratio. Relative to CuSO(4)-containing systems, CuCl(2) mediated MIT loading was unstable. Both nigericin and ammonium could alter the absorption spectra of liposomal MITs loaded with CuSO(4) gradient. In vitro release studies were performed in glucose/histidine buffer and in 50% human plasma using a dialysis method. In both of release media, CuCl(2)-containing vesicles displayed rapid release kinetics in comparison with CuSO(4) systems; and during the experiment period, MIT was lost from the vesicles continuously. When the formulations were injected into BDF1 mice at a dose of 4 mg/kg, all the liposomal formulations exhibited enhanced blood circulation time, with half-life values of 6.8-7.2h, significantly compared to the rapid clearance of free-MIT. In L1210 ascitic model, CuCl(2) formulation was more therapeutically active than CuSO(4) formulation. At a dose of 6 mg/kg, the treatment with CuCl(2) formulation resulted in

  20. The effects on bone cells of metal ions released from orthopaedic implants. A review

    PubMed Central

    Sansone, Valerio; Pagani, Davide; Melato, Marco

    2013-01-01

    Summary The increasing use of orthopedic implants and, in particular, of hip and knee joint replacements for young and active patients, has stimulated interest and concern regarding the chronic, long-term effects of the materials used. This review focuses on the current knowledge of the adverse biologic reactions to metal particles released from orthopaedic implants in vivo and in vitro. More specifically, the purpose of this article is to provide an overview of the current literature about the adverse effects of metal particles on bone cells and peri-implant bone. PMID:23858309

  1. Preliminary evaluation of therapeutic ion release from Sr-doped zinc-silicate glass ceramics.

    PubMed

    Looney, Mark; O'Shea, Helen; Boyd, Daniel

    2013-01-01

    Bioactive and degradable porous bioceramics play an important role in many clinical situations. Porosity is essential to the performance of a material that is proposed to be used as an implantable osseous scaffold. Scaffolds provide a three dimensional support and template to osseous integration and vascularization. Combining the porosity of a scaffold with the ability of the scaffold material to deliver therapeutic ions to the site of implantation goes some way towards developing an ideal bone graft. A series of strontium-doped zinc silicate (Ca-Sr-Na-Zn-Si) glass ceramics scaffoldswere developed, whose porosity was measured to be between 93% and 96%, which is advantageous in terms of osseous integration and vascularization. The levels of Zn(2+) and Sr(2+) detected as a result of degradation of the crystalline phases were found to be 1.4-600 parts per million (ppm) and 0-583 ppm, respectively. The levels detected correlate well with the levels of Sr(2+) and Zn(2+)ions typically associated with clinical benefits, including antibacterial efficacy, osteoblastic differentiation and impaired osteoclastic resorption. PMID:21926151

  2. Clinoenstatite coatings have high bonding strength, bioactive ion release, and osteoimmunomodulatory effects that enhance in vivo osseointegration.

    PubMed

    Wu, Chengtie; Chen, Zetao; Wu, Qianju; Yi, Deliang; Friis, Thor; Zheng, Xuebin; Chang, Jiang; Jiang, Xinquan; Xiao, Yin

    2015-12-01

    A number of coating materials have been developed over past two decades seeking to improve the osseointegration of orthopedic metal implants. Despite the many candidate materials trialed, their low rate of translation into clinical applications suggests there is room for improving the current strategies for their development. We therefore propose that the ideal coating material(s) should possess the following three properties: (i) high bonding strength, (ii) release of functional ions, and (iii) favourable osteoimmunomodulatory effects. To test this proposal, we developed clinoenstatite (CLT, MgSiO3), which as a coating material has high bonding strength, cytocompability and immunomodulatory effects that are favourable for in vivo osteogenesis. The bonding strength of CLT coatings was 50.1 ± 3.2 MPa, more than twice that of hydroxyapatite (HA) coatings, at 23.5 ± 3.5 MPa. CLT coatings released Mg and Si ions, and compared to HA coatings, induced an immunomodulation more conducive for osseointegration, demonstrated by downregurelation of pro-inflammatory cytokines, enhancement of osteogenesis, and inhibition of osteoclastogenesis. In vivo studies demonstrated that CLT coatings improved osseointegration with host bone, as shown by the enhanced biomechanical strength and increased de novo bone formation, when compared with HA coatings. These results support the notion that coating materials with the proposed properties can induce an in vivo environment better suited for osseointegration. These properties could, therefore, be fundamental when developing high-performance coating materials. PMID:26318815

  3. Mass analysis of neutral particles and ions released during electrical breakdowns on spacecraft surfaces

    NASA Technical Reports Server (NTRS)

    Kendall, B. R. F.

    1983-01-01

    A specialized spectrometer was designed and developed to measure the mass and velocity distributions of neutral particles (molecules and molecular clusters) released from metal-backed Teflon and Kapton films. Promising results were obtained with an insulation breakdown initiation system based on a moveable contact touching the insulated surfaces. A variable energy, high voltage pulse is applied to the contact. The resulting surface damage sites can be made similar in size and shape to those produced by a high voltage electron beam system operating at similar discharge energies. The point discharge apparatus was used for final development of several high speed recording systems and for measurements of the composition of the materials given off by the discharge. Results with this apparatus show evolution of large amounts of fluorocarbon fragments from discharge through Teflon FEP, while discharges through Kapton produce mainly very light hydrocarbon fragments at masses below about 80 a.m.u.

  4. Voltage-activated ion channels and Ca2+-induced Ca2+ release shape Ca2+ signaling in Merkel cells

    PubMed Central

    Piskorowski, Rebecca; Haeberle, Henry; Panditrao, Mayuri V.; Lumpkin, Ellen A.

    2008-01-01

    Ca2+ signaling and neurotransmission modulate touch-evoked responses in Merkel cell–neurite complexes. To identify mechanisms governing these processes, we analyzed voltage-activated ion channels and Ca2+ signaling in purified Merkel cells. Merkel cells in the intact skin were specifically labeled by antibodies against voltage-activated Ca2+ channels (CaV2.1) and voltage- and Ca2+-activated K+ (BKCa) channels. Voltage-clamp recordings revealed small Ca2+ currents, which produced Ca2+ transients that were amplified sevenfold by Ca2+-induced Ca2+ release. Merkel cells' voltage-activated K+ currents were carried predominantly by BKCa channels with inactivating and noninactivating components. Thus, Merkel cells, like hair cells, have functionally diverse BKCa channels. Finally, blocking K+ channels increased response magnitude and dramatically shortened Ca2+ transients evoked by mechanical stimulation. Together, these results demonstrate that Ca2+ signaling in Merkel cells is governed by the interplay of plasma membrane Ca2+ channels, store release and K+ channels, and they identify specific signaling mechanisms that may control touch sensitivity. PMID:18415122

  5. The salt and lipid composition of model cheeses modifies in-mouth flavour release and perception related to the free sodium ion content.

    PubMed

    Boisard, Lauriane; Andriot, Isabelle; Martin, Christophe; Septier, Chantal; Boissard, Vanessa; Salles, Christian; Guichard, Elisabeth

    2014-02-15

    Reducing salt and lipid levels in foodstuffs without any effect on acceptability is a major challenge, particularly because of their interactions with other ingredients. This study used a multimodal approach to understand the effects of changes to the composition of model cheeses (20/28, 24/24, 28/20 lipid/protein ratios, 0% and 1% added NaCl) on sodium ion mobility ((23)Na NMR), in-mouth sodium release and flavour perception. An increase in the salt content decreased cheese firmness and perceived hardness, and increased sodium ion mobility, in vivo sodium release and both saltiness and aroma perception. With the same amount of salt, a lower lipid/protein ratio increased the firmness of the cheeses, perceived hardness, and decreased sodium ion mobility, in vivo sodium release, saltiness and aroma perception. These findings suggest on one hand that it could be possible to increase saltiness perception by varying cheese composition, thus inducing differences in sodium ion mobility and in free sodium ion concentration, leading to differences in in-mouth sodium release and saltiness perception, and on the other hand that the reformulation of foods in line with health guidelines needs to take account of both salt content and the lipid/protein ratio. PMID:24128499

  6. Guidelines for Designing Surface Ion Traps Using the Boundary Element Method

    PubMed Central

    Hong, Seokjun; Lee, Minjae; Cheon, Hongjin; Kim, Taehyun; Cho, Dong-il “Dan”

    2016-01-01

    Ion traps can provide both physical implementation of quantum information processing and direct observation of quantum systems. Recently, surface ion traps have been developed using microfabrication technologies and are considered to be a promising platform for scalable quantum devices. This paper presents detailed guidelines for designing the electrodes of surface ion traps. First, we define and explain the key specifications including trap depth, q-parameter, secular frequency, and ion height. Then, we present a numerical-simulation-based design procedure, which involves determining the basic assumptions, determining the shape and size of the chip, designing the dimensions of the radio frequency (RF) electrode, and analyzing the direct current (DC) control voltages. As an example of this design procedure, we present a case study with tutorial-like explanations. The proposed design procedure can provide a practical guideline for designing the electrodes of surface ion traps. PMID:27136559

  7. Guidelines for Designing Surface Ion Traps Using the Boundary Element Method.

    PubMed

    Hong, Seokjun; Lee, Minjae; Cheon, Hongjin; Kim, Taehyun; Cho, Dong-Il Dan

    2016-01-01

    Ion traps can provide both physical implementation of quantum information processing and direct observation of quantum systems. Recently, surface ion traps have been developed using microfabrication technologies and are considered to be a promising platform for scalable quantum devices. This paper presents detailed guidelines for designing the electrodes of surface ion traps. First, we define and explain the key specifications including trap depth, q-parameter, secular frequency, and ion height. Then, we present a numerical-simulation-based design procedure, which involves determining the basic assumptions, determining the shape and size of the chip, designing the dimensions of the radio frequency (RF) electrode, and analyzing the direct current (DC) control voltages. As an example of this design procedure, we present a case study with tutorial-like explanations. The proposed design procedure can provide a practical guideline for designing the electrodes of surface ion traps. PMID:27136559

  8. Stanford-USGS shrimp-RG ion microprobe: A new approach to determining the distribution of trace elements in coal

    USGS Publications Warehouse

    Kolker, A.; Wooden, J.L.; Persing, H.M.; Zielinski, R.A.

    2000-01-01

    The distribution of Cr and other trace metals of environmental interest in a range of widely used U.S. coals was investigated using the Stanford-USGS SHRIMP-RG ion microprobe . Using the oxygen ion source, concentrations of Cr (11 to 176 ppm), V (23 to 248 ppm), Mn (2 to 149 ppm), Ni (2 to 30 ppm), and 13 other elements were determined in illite/smectite, a group of clay minerals commonly present in coal. The results confirm previous indirect or semi-quantitative determinations indicating illite/smectite to be an important host of these metals. Calibration was achieved using doped aluminosilicate-glass synthetic standards and glasses prepared from USGS rock standards. Grains for analysis were identified optically, and confirmed by 1) precursory electron microprobe analysis and wavelength-dispersive compositional mapping, and 2) SHRIMP-RG major element data obtained concurrently with trace element results. Follow-up investigations will focus on the distribution of As and other elements that are more effectively ionized with the cesium primary beam currently being tested.

  9. The Effect of Annealing at 1500 C on Migration and Release of Ion Implanted Silver in CVD Silicon Carbide

    SciTech Connect

    HJ MacLean; RG Ballinger; LE Kolaya; SA Simonson; N Lewis; M Hanson

    2004-10-07

    The transport of silver in CVD {beta}-SiC has been studied using ion implantation. Silver ions were implanted in {beta}-SiC using the ATLAS accelerator facility at the Argonne National Laboratory. Ion beams with energies of 93 and 161 MeV were used to achieve deposition with peak concentrations at depths of approximately 9 and 13 {micro}m, respectively. As-implanted samples were then annealed at 1500 C for 210 or 480 hours. XPS, SEM, TEM, STEM, and optical methods were used to analyze the material before and after annealing. Silver concentration profiles were determined using XPS before and after annealing. STEM and SEM equipped with quantitative chemical analysis capability were used to more fully characterize the location and morphology of the silver before and after annealing. The results show that, within the uncertainty of measurement techniques, there is no silver migration, via either inter- or intragrannular paths, for the times and temperature studied. Additionally, the silver was observed to phase separate within the SiC after annealing. The irradiation damage from the implantation process resulted in a three-layer morphology in the as-implanted condition: (1) a layer of unaltered SiC, followed by (2) a layer of crystallized SiC, followed by (3) an amorphized layer which contained essentially all of the implanted silver. After annealing the layer structure changed. Layer 1 was unaltered. The grains in layer 2 recrystallized to form an epitaxial (columnar) layer. Layer 3 recrystallized to form a fine grain equiaxed layer. The results of this work do not support the long held assumption that silver release from CVD SiC, used for gas-reactor coated particle fuel, is dominated by grain boundary diffusion.

  10. Multi-Element Preconcentration/Separation of Some Metal Ions in Environmental Samples by Using Co-precipitation.

    PubMed

    Soylak, Mustafa; Aydin, Ayse; Kizil, Nebiye

    2016-01-01

    A preconcentration/separation system for cadmium(II), nickel(II), copper(II), lead(II), iron(II), cobalt(II), and manganese(II) ions has been established prior to their atomic absorption spectrometric determinations. The procedure is based on the co-precipitation of these ions by the aid of a praseodymium hydroxide (Pr(OH)3) precipitate. The precipitate was dissolved in 0.5 mL of concentrated HNO3, and made up to 10.0 mL with water. The analytes were determined by a flame atomic absorption spectrometer. The effects of analytical parameters including pH, amounts of praseodymium as carrier element, sample volume, etc. on the recoveries of heavy metals were investigated. The effects of matrix ions were also examined. The limits of detection for analyte ions were found in the range between 0.7-5.2 μg/L. The validation of this present procedure was verified by the analysis of certified reference materials, TMDA-54.4 (fortified water) and NIST 1570a (spinach leaves). The proposed co-precipitation procedure was applied for the determination of cadmium(II), nickel(II), copper(II), lead(II), iron(II), cobalt(II), and manganese(II) ions in various environmental water samples. PMID:27053469

  11. Effect of temperature on the release and remobilization of ecotoxic elements in AMD colloidal precipitates: the example of the Libiola copper mine, Liguria, (Italy).

    PubMed

    Consani, S; Carbone, C; Salviulo, G; Zorzi, F; Dinelli, E; Botter, R; Nodari, L; Badocco, D; Lucchetti, G

    2016-07-01

    Due to their characteristics, colloidal particles are able to control the dispersion of many organic and inorganic pollutants in soils and streams. Colloidal precipitates generated by acid mine drainage (AMD) process are usually amorphous or nanocrystalline materials, and their stability plays a crucial role in controlling the fate of metals released by sulphide oxydation. This paper describes a study of elements release (Fe, Al, Mn, Cd, Co, Cr, Cu, Ni, S, Zn) due to desorption or destabilization of three different colloidal precipitates, two ochreous and a greenish-blue precipitate, sampled at the Libiola mine site (northwest Italy). The samples were heated at high temperature in order to verify this treatment as inertization process. At room temperature, the most easily extracted element was S (with released percentages from 8.39 to 29.17 %), but considerable amounts of Cu, Zn and Mn (up to 16.6, 610.6 and 595.6 mg/kg, respectively) were also observed in the leachates for greenish-blue precipitates. The highest release of elements (S > Cu, Zn, Mn, Cd > Co, Ni > Al, Fe, Cr), with minor differences depending on the mineralogical composition of the samples, was observed for heat-treated samples obtained through moderate heating and mainly formed by anhydrous phases. Samples treated at high temperature had the lowest release, with only Cu showing a significant concentration in the leachate of greenish-blue precipitates. The results showed that dissolution/desorption is limited from ochreous natural colloidal precipitates occurring at the Libiola mine site but also that high amounts of some metals can be remobilized from greenish-blue precipitates. The destabilization of all percipitates through dehydratation-dehydroxylation can further remobilize important amounts of ecotoxic elements. Heat treatment at high temperature could be a definitive, although expensive, way to fix heavy metals in the solid fraction, preventing their dispersion in the surrounding

  12. Enhanced flow injection leaching of rocks by focused microwave heating with in-line monitoring of released elements by inductively coupled plasma mass spectrometry.

    PubMed

    Silva, Milithza; Kyser, Kurt; Beauchemin, Diane

    2007-02-19

    A focused microwave digestion system was used to heat a mini-column of sample of crushed rock (hematite) during its successive leaching by repeated 250-microL injections of water, HNO(3) 1%, 10% and 30% (v/v). The mini-column was connected to the nebulizer of an inductively coupled plasma mass spectrometry instrument, which allowed a continuous monitoring of the progressive release of elements by a given leaching reagent. Quantitation of the accessible fraction of Mg, V, Cr, Mn, Co, Ni, Cu, Zn, Mo, Sb and Pb was done by calibration using 250-microL injections of standard solutions prepared in the leaching reagent matrices. Total digestion of the sample residue was also done to verify mass balance. With the exception of Mg, V and Co, where the same total amount was released with or without microwave heating, an increased release resulted from focused microwave heating, by up to an order of magnitude. Furthermore, mass balance was verified for more elements using microwave heating, presumably because of a lower relative proportion of spectroscopic interference as a result of an increased release of analytes. Using microwave energy in general resulted in the dissolution of additional phases, as evidenced by significantly different (208)Pb/(206)Pb ratios as well as the increased release of elements with milder reagents. In fact, in the case of Pb, leaching with 30% HNO(3) was no longer necessary as all the Pb was released in the first three leaching reagents. Microwave heating could therefore be used advantageously in on-line leaching for exploration geochemistry and environmental monitoring. PMID:17386636

  13. Polyglycerol-Based Copper Chelators for the Transport and Release of Copper Ions in Biological Environments.

    PubMed

    Albrecht, Ralf; Fehse, Susanne; Pant, Kritee; Nowag, Sabrina; Stephan, Holger; Haag, Rainer; Tzschucke, Carl Christoph

    2016-03-01

    Here, the synthesis and characterization of three improved nanosystems is presented based on amino functionalized hyperbranched polyglycerol (hPG; M(w) = 16.8 kDa) as potential copper(II) chelators. The ligands, N-methyl-N-picolylglycine amide, 2,6-pyridine dicarboxylic acid monoamide, and cyclam tetraacetic acid (TETA) monoamide, are covalently attached to the polymer with amide bonds. In this paper, the Cu(II) loading capacity, the stability of the Cu(II)-loaded carriers at different pHs, with competing ligands and in human serum, as well as the transport of Cu(II) in biological systems are investigated. For the first time, a different cytotoxicity of functionalized polymer nanoparticles with and without Cu(II) is observed. The cyclam-based carrier combines the highest loading capacity (29 Cu ions/nanoparticle), best stability with respect to pH and EDTA (45% remaining Cu after 24 h), lowest cytotoxicity (IC50 > 100 × 10(-6) M (unloaded), 1500 × 10(-6) M Cu(II); Cu:carrier 29:1), and the highest stability in human serum. PMID:26644323

  14. Atmospheric trace element and major ion concentrations over the eastern Mediterranean Sea: Identification of anthropogenic source regions

    NASA Astrophysics Data System (ADS)

    Güllü, Gülen; Doğan, Güray; Tuncel, Gürdal

    Concentrations of elements and ions measured in aerosol samples collected from March 1992 to the end of December 1993 were investigated to identify source regions affecting chemical composition of aerosols in the eastern Mediterranean atmosphere. Collected samples were analyzed for approximately 40 elements and ions using a combination of atomic absorption spectrometry, instrumental neutron activation analysis, ion chromatography and colorimetry. Statistical techniques, such as enrichment factors and a non-parametric bootstrapped potential source contribution function, were applied on the data set to determine main source types and source regions of anthropogenic particles in the eastern Mediterranean basin. Source regions of two previously defined anthropogenic components, namely a long-range transported component and a local pollution component, were identified. The main source areas for pollutants reaching the eastern Mediterranean basin were determined as southern and western parts of Turkey, central and eastern regions of Ukraine, east of Belarus, Greece, Georgia, Romania, coastal areas along France and Spain and coastal areas around the Black Sea, Russia. More distant source regions in the South of UK and Sweden, the central part of Algeria, the northeastern part of Turkey, Russia, Germany, Hungary, Czech Republic, Bosnia and Herzegovina, and coastal areas of Egypt, Israel and Italy do affect aerosol composition in the eastern Mediterranean, but transport from these regions cannot account for the highest 20% of the measured pollutant concentrations.

  15. Geochemical and mineralogical controls on trace element release from the Penn Mine base-metal slag dump, California

    USGS Publications Warehouse

    Parsons, M.B.; Bird, D.K.; Einaudi, M.T.; Alpers, C.N.

    2001-01-01

    phase precipitation. Close agreement between model results and measured concentrations of Al, Ba, Cu, Fe, SiO2, and SO4 in the slag dump pore waters suggests that the dissolved concentrations of these elements are controlled by solubility equilibrium with secondary phases. Differences between predicted and measured Cd and Pb concentrations imply that field weathering rates of glass and sulfides are approximately two orders of magnitude lower than laboratory rates. Overprediction of Pb release may also reflect other attenuation processes in the natural system, such as sorption or coprecipitation. ?? 2001 Elsevier Science Ltd. All rights reserved.

  16. Corrosion, ion release and Mott–Schottky probe of chromium oxide coatings in saline solution with potential for orthopaedic implant applications

    NASA Astrophysics Data System (ADS)

    Ogwu, A. A.; Oje, A. M.; Kavanagh, J.

    2016-04-01

    We report our investigation on chromium oxide thin film coatings that show a negligible ion release during electrochemical corrosion testing in saline solution. The chemical constituents of the films prepared by reactive magnetron sputtering were identified to be predominantly Cr2O3 based on Raman spectroscopy anti-symmetric stretching vibration modes for CrIII–O and other peaks and an FTIR spectroscopy E u vibrational mode at 409 cm‑1. X-ray photoelectron spectroscopy, multiplet fitting for 2P 3/2 and 2P 1/2 states also confirmed the predominantly Cr2O3 stoichiometry in the films. The prepared chromium oxide coatings showed superior pitting corrosion resistance compared to the native chromium oxide films on bare uncoated stainless steel when tested under open circuit potential, potentiodynamic polarisation and cyclic voltammetry in saline solution. The chromium ion released into solution during the corrosion testing of stainless steel substrates coated with chromium oxide coatings was found to be negligibly small based on atomic absorption spectroscopy measurements. Our Mott–Schottky analysis investigation showed that the negligibly small ion release from the chromium oxide coated steel substrates is most likely due to a much lower defect density on the surface of the deposited coatings compared to the native oxide layer on the uncoated steel substrates. This opens up the opportunity for using chromium oxide surface coatings in hip, knee and other orthopaedic implants where possible metal ion release in vivo still poses a great challenge.

  17. Evaluation of Nickel and Chromium Ion Release During Fixed Orthodontic Treatment Using Inductively Coupled Plasma-Mass Spectrometer: An In Vivo Study

    PubMed Central

    Nayak, Rabindra S; Khanna, Bharti; Pasha, Azam; Vinay, K; Narayan, Anjali; Chaitra, K

    2015-01-01

    Background: Fixed orthodontic appliances with the use of stainless steel brackets and archwires made of nitinol have a corrosive potential in the oral environment. Nickel and chromium ions released from these appliances act as allergens apart from being cytotoxic, mutagenic and carcinogenic in smaller quantities in the range of nanograms. This study was done to evaluate the release of nickel and chromium ions from orthodontic appliances in the oral cavity using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Materials and Methods: Saliva samples from 30 orthodontic patients undergoing treatment with 0.022″ MBT mechanotherapy were collected prior to commencement of treatment, after initial aligning wires and after 10-12 months of treatment. Salivary nickel and chromium ion concentration was measured in parts per billion (ppb) using ICP-MS. Results: Mean, standard deviation and range were computed for the concentrations of ions obtained. Results analyzed using ANOVA indicated a statistically significant increase of 10.35 ppb in nickel ion concentration and 33.53 ppb in chromium ion concentration after initial alignment. The ionic concentration at the end of 10-12 months of treatment showed a statistically significant increase in of 17.92 ppb for chromium and a statistically insignificant decrease in nickel ion concentration by 1.58 ppb. Pearson’s correlation coefficient showed a positive correlation for an increase in nickel concentration after aligning, but not at the end of 10-12 months. A positive correlation was seen for an increase in chromium ion concentration at both time intervals. Conclusion: Nickel and chromium ion concentration in saliva even though below the recommended daily allowance should not be ignored in light of the new knowledge regarding effects of these ions at the molecular level and the allergic potential. Careful and detailed medical history of allergy is essential. Nickel free alternatives should form an essential part of an

  18. Some Rare Earth Elements Analysis by Microwave Plasma Torch Coupled with the Linear Ion Trap Mass Spectrometry

    PubMed Central

    Xiong, Xiaohong; Jiang, Tao; Qi, Wenhao; Zuo, Jun; Yang, Meiling; Fei, Qiang; Xiao, Saijin; Yu, Aimin; Zhu, Zhiqiang; Chen, Huanwen

    2015-01-01

    A sensitive mass spectrometric analysis method based on the microwave plasma technique is developed for the fast detection of trace rare earth elements (REEs) in aqueous solution. The plasma was produced from a microwave plasma torch (MPT) under atmospheric pressure and was used as ambient ion source of a linear ion trap mass spectrometer (LTQ). Water samples were directly pneumatically nebulized to flow into the plasma through the central tube of MPT. For some REEs, the generated composite ions were detected in both positive and negative ion modes and further characterized in tandem mass spectrometry. Under the optimized conditions, the limit of detection (LOD) was at the level 0.1 ng/mL using MS2 procedure in negative mode. A single REE analysis can be completed within 2~3 minutes with the relative standard deviation ranging between 2.4% and 21.2% (six repeated measurements) for the 5 experimental runs. Moreover, the recovery rates of these REEs are between the range of 97.6%–122.1%. Two real samples have also been analyzed, including well and orange juice. These experimental data demonstrated that this method is a useful tool for the field analysis of REEs in water and can be used as an alternative supplement of ICP-MS. PMID:26421013

  19. Some Rare Earth Elements Analysis by Microwave Plasma Torch Coupled with the Linear Ion Trap Mass Spectrometry.

    PubMed

    Xiong, Xiaohong; Jiang, Tao; Qi, Wenhao; Zuo, Jun; Yang, Meiling; Fei, Qiang; Xiao, Saijin; Yu, Aimin; Zhu, Zhiqiang; Chen, Huanwen

    2015-01-01

    A sensitive mass spectrometric analysis method based on the microwave plasma technique is developed for the fast detection of trace rare earth elements (REEs) in aqueous solution. The plasma was produced from a microwave plasma torch (MPT) under atmospheric pressure and was used as ambient ion source of a linear ion trap mass spectrometer (LTQ). Water samples were directly pneumatically nebulized to flow into the plasma through the central tube of MPT. For some REEs, the generated composite ions were detected in both positive and negative ion modes and further characterized in tandem mass spectrometry. Under the optimized conditions, the limit of detection (LOD) was at the level 0.1 ng/mL using MS(2) procedure in negative mode. A single REE analysis can be completed within 2~3 minutes with the relative standard deviation ranging between 2.4% and 21.2% (six repeated measurements) for the 5 experimental runs. Moreover, the recovery rates of these REEs are between the range of 97.6%-122.1%. Two real samples have also been analyzed, including well and orange juice. These experimental data demonstrated that this method is a useful tool for the field analysis of REEs in water and can be used as an alternative supplement of ICP-MS. PMID:26421013

  20. Acoustic signals generated in piezoelectric lead zirconate titanate elements by direct bombardment with xenon ions

    NASA Astrophysics Data System (ADS)

    Miyachi, T.; Nakamura, Y.; Kuraza, G.; Fujii, M.; Nagashima, A.; Hasebe, N.; Kobayashi, M. N.; Kobayashi, S.; Miyajima, M.; Mori, K.; Okudaira, O.; Yamashita, N.; Shibata, H.; Murakami, T.; Uchihori, Y.; Okada, N.

    2006-12-01

    Acoustic signals were observed with a lead-zirconate-titanate (PZT) element that was directly irradiated with a 368 MeV/n xenon beam. Using an array comprising PZT elements, the energy loss in the PZT was studied. These elements are sensitive to an energy deposit of 100 nJ. A series of values of output voltage vs. integrated thickness of PZT was represented along a line similar to the ionization loss calculated by the Bethe-Bloch formula. The induced voltage was attributed to several processes—ionization, thermal, elastic, and piezoelectric processes. This study describes the possible applications of the PZT element as an active medium for calorimeters and a monitor for hypervelocity impact of space dust.

  1. AUTOMATED ELEMENTAL COMPOSITION DETERMINATION AND CORRELATION OF PRECURSOR WITH PRODUCT IONS BASED ON ORTHOGONAL ACCELERATION, TIME-OF-FLIGHT MASS SPECTRA

    EPA Science Inventory

    For more than a decade in our laboratory, elemental compositions of ions in mass spectra havebeen routinely determined by measuring exact masses and relative isotopic abundances of ions in isotopicclusters using a GC coupled to a double focusing mass spectrometer.1 HPLC interfac...

  2. NUMEN Project @ LNS : Heavy ions double charge exchange reactions towards the 0νββ nuclear matrix element determination

    SciTech Connect

    Agodi, C. Calabretta, L.; Calanna, A.; Carbone, D.; Cavallaro, M.; Colonna, M.; Cuttone, G.; Finocchiaro, P.; Pandola, L.; Rifuggiato, D.; Tudisco, S.; Cappuzzello, F.; Greco, V.; Bonanno, D. L.; Bongiovanni, D. G.; Longhitano, F.; Branchina, V.; Foti, A.; Lo Presti, D.; Lanzalone, G.; and others

    2015-10-28

    In the NUMEN Project it is proposed an innovative technique to access the nuclear matrix elements entering in the expression of the life-time of the neutrinoless double beta decay, using relevant cross sections of double charge exchange reactions. A key aspect is the use of MAGNEX large acceptance magnetic spectrometer, for the detection of the ejectiles, and of the INFN Laboratori Nazionali del Sud (LNS) K800 Superconducting Cyclotron (CS), for the acceleration of the required high resolution and low emittance heavy-ion beams.

  3. NUMEN Project @ LNS : Heavy ions double charge exchange reactions towards the 0νββ nuclear matrix element determination

    NASA Astrophysics Data System (ADS)

    Agodi, C.; Cappuzzello, F.; Bonanno, D. L.; Bongiovanni, D. G.; Branchina, V.; Calabretta, L.; Calanna, A.; Carbone, D.; Cavallaro, M.; Colonna, M.; Cuttone, G.; Foti, A.; Finocchiaro, P.; Greco, V.; Lanzalone, G.; Lo Presti, D.; Longhitano, F.; Muoio, A.; Pandola, L.; Rifuggiato, D.; Tudisco, S.

    2015-10-01

    In the NUMEN Project it is proposed an innovative technique to access the nuclear matrix elements entering in the expression of the life-time of the neutrinoless double beta decay, using relevant cross sections of double charge exchange reactions. A key aspect is the use of MAGNEX large acceptance magnetic spectrometer, for the detection of the ejectiles, and of the INFN Laboratori Nazionali del Sud (LNS) K800 Superconducting Cyclotron (CS), for the acceleration of the required high resolution and low emittance heavy-ion beams.

  4. Hydrophobic ion pairing of a minocycline/Ca(2+)/AOT complex for preparation of drug-loaded PLGA nanoparticles with improved sustained release.

    PubMed

    Holmkvist, Alexander Dontsios; Friberg, Annika; Nilsson, Ulf J; Schouenborg, Jens

    2016-02-29

    Polymeric nanoparticles is an established and efficient means to achieve controlled release of drugs. Incorporation of minocycline, an antibiotic with anti-inflammatory and neuroprotective properties, into biodegradable nanoparticles may therefore provide an efficient means to combat foreign body reactions to implanted electrodes in the brain. However, minocycline is commonly associated with poor encapsulation efficiencies and/or fast release rates due to its high solubility in water. Moreover, minocycline is unstable under conditions of low and high pH, heat and exposure to light, which exacerbate the challenges of encapsulation. In this work drug loaded PLGA nanoparticles were prepared by a modified emulsification-solvent-diffusion technique and characterized for size, drug encapsulation and in vitro drug release. A novel hydrophobic ion pair complex of minocycline, Ca(2+) ions and the anionic surfactant AOT was developed to protect minocycline from degradation and prolong its release. The optimized formulation resulted in particle sizes around 220 nm with an entrapment efficiency of 43% and showed drug release over 30 days in artificial cerebrospinal fluid. The present results constitute a substantial increase in release time compared to what has hitherto been achieved for minocycline and indicate that such particles might provide useful for sustained drug delivery in the CNS. PMID:26773599

  5. Behavior of transplutonium elements on ion-exchange materials in mixed aqueous-organic solutions of mineral acids

    SciTech Connect

    Guseva, L.I.; Tikhomirov, G.S.; Stepushkina, V.V.

    1987-03-01

    Systematic studies are reported on the behavior of transplutonium elements (TPE) on cation-exchange and anion-exchange materials in mixed aqueous-organic solutions of mineral acids (HClO/sub 4/, HCl, HNO/sub 3/, H/sub 2/SO/sub 4/, H/sub 3/PO/sub 4/) as affected by solution composition, nature of acid, and nature of organic solvent. With all these acids, replacing most of the water by alcohol increases the TPE uptake on the ion exchangers, and the effect occurs for the cation exchangers at lower contents of the organic component. Optimum conditions have been identified for concentrating and separating TPE from numerous elements. The most effective system consists of anion exchanger with HNO/sub 3/ and alcohol.

  6. Effects of alloying elements on the formation of < c >-component loops in Zr alloy Excel under heavy ion irradiation.

    SciTech Connect

    Idrees, Yasir; Francis, Elisabeth M.; Yao, Zhongwen; Korinek, Andreas; Kirk, Marquis A.; Sattari, Mohammad; Preuss, Michael; Daymond, M. R.

    2015-05-14

    We report here the microstructural changes occurring in the zirconium alloy Excel (Zr-3.5 wt% Sn-0.8Nb-0.8Mo-0.2Fe) during heavy ion irradiation. In situ irradiation experiments were conducted at reactor operating temperatures on two Zr Excel alloy microstructures with different states of alloying elements, with the states achieved by different solution heat treatments. In the first case, the alloying elements were mostly concentrated in the beta (beta) phase, whereas, in the second case, large Zr-3(Mo,Nb,Fe)(4) secondary phase precipitates (SPPs) were grown in the alpha (alpha) phase by long term aging. The heavy ion induced damage and resultant compositional changes were examined using transmission electron microscopy (TEM) in combination with scanning transmission electron microscope (STEM)-energy dispersive x-ray spectroscopy (EDS) mapping. Significant differences were seen in microstructural evolution between the two different microstructures that were irradiated under similar conditions. Nucleation and growth of < c >-component loops and their dependence on the alloying elements are a major focus of the current investigation. It was observed that the < c >-component loops nucleate readily at 100, 300, and 400 degrees C after a threshold incubation dose (TID), which varies with irradiation temperature and the state of alloying elements. It was found that the TID for the formation of < c >-component loops increases with decrease in irradiation temperature. Alloying elements that are present in the form of SPPs increase the TID compared to when they are in the beta phase solid solution. Dose and temperature dependence of loop size and density are presented. Radiation induced redistribution and clustering of alloying elements (Sn, Mo, and Fe) have been observed and related to the formation of < c >-component loops. It has been shown that at the higher temperature tests, irradiation induced dissolution of precipitates occurs whereas irradiation induced

  7. Metal ion-assisted drug-loading model for novel delivery system of cisplatin solid lipid nanoparticles with improving loading efficiency and sustained release.

    PubMed

    Yang, Caiqin; Lv, Jie; Lv, Tao; Pan, Yahui; Han, Yazhu; Zhao, Sha; Wang, Jing

    2016-05-01

    Metal ion-assisted drug loading model, in which metal ion was used to modify the microstructure of lipid layer, has been developed to improve drug loading efficiency of solid lipid nanoparticles (SLNs). The microstructure and properties of metal ion-assisted cisplatin-loading SLNs were investigated by infra-red spectroscopy, fluorescence spectroscopy and zetasizer. The reactions of hydrogenated soybean lecithin with Zn(2+), Cu(2+), Mn(2+ )and Mg(2+ )have been detected; the mechanism for higher drug encapsulation efficiency (EE) has been investigated. In metal ion introduction SLNs, the compact degree of the lipid molecules was increased due to the electrostatic interaction between metal ions and phospholipid acyl and choline polarity groups, which result in increasing of drug EE. Meanwhile, these electrostatic interactions slowed the releasing rate of encapsulated drug. The study of cytotoxic activity in vitro indicated that the cell cytotoxicity of metal ions introduction SLNs depended on both cell uptake of SLNs and drug releasing from SLNs. PMID:27113257

  8. Angle-resolved intensity and energy distributions of positive and negative hydrogen ions released from tungsten surface by molecular hydrogen ion impact

    NASA Astrophysics Data System (ADS)

    Kato, S.; Tanaka, N.; Sasao, M.; Kisaki, M.; Tsumori, K.; Nishiura, M.; Matsumoto, Y.; Kenmotsu, T.; Wada, M.; Yamaoka, H.

    2015-08-01

    Hydrogen ion reflection properties have been investigated following the injection of H+, H2+ and H3+ ions onto a polycrystalline W surface. Angle- and energy-resolved intensity distributions of both scattered H+ and H- ions are measured by a magnetic momentum analyzer. We have detected atomic hydrogen ions reflected from the surface, while molecular hydrogen ions are unobserved within our detection limit. The reflected hydrogen ion energy is approximately less than one-third of the incident beam energy for H3+ ion injection and less than a half of that for H2+ ion injection. Other reflection properties are very similar to those of monoatomic H+ ion injection. Experimental results are compared to the classical trajectory simulations using the ACAT code based on the binary collision approximation.

  9. Water-soluble ions and trace elements in surface snow and their potential source regions across northeastern China

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Pu, Wei; Zhang, Xueying; Ren, Yong; Huang, Jianping

    2015-08-01

    We collected 92 snow samples from 13 sites across northeastern China from January 7 to February 15, 2014. The surface snow samples were analyzed for the major water-soluble ions (SO42-, NO3-, F-, Cl-, Na+, K+, Ca2+, Mg2+, and NH4+) and trace element (Al, As, Mn, V, Cd, Cu, Pb, Zn, Fe, Cr, and Ni). The results indicated that the higher concentrations of NO3- and SO42- and the trace elements Zn, Pb, Cd, Ni, and Cu were likely attributable to enhanced local industrial emissions in East Asia especially in China. In addition, snow samples characterized by higher enrichment factors of trace elements (Cu, Cd, As, Zn, Pb) were indicative of an anthropogenic source. Emissions from fossil fuel combustion and biomass burning were likely important contributors to the chemical elements in seasonal snow with long-range transport. On the other hand, the large attribution of K+ appeared in the higher latitude demonstrated that biomass burning was a dominated factor of the chemical species in seasonal snow in the higher latitude of China than that in the lower latitude. Finally, an interannual comparison with the 2010 China snow survey also confirmed the source attributions of chemical speciation in seasonal snow in these regions.

  10. Release of deuterium from irradiation damage in Fe-9Cr-2W ferritic alloy irradiated with deuterium ions

    NASA Astrophysics Data System (ADS)

    Ono, K.; Miyamoto, M.; Kudo, F.

    2014-09-01

    The release profile of deuterium from an Fe-9Cr-2W ferritic alloy irradiated with low-energy deuterium ions was studied by thermal desorption spectroscopy (TDS) and in situ transmission electron microscopy (TEM). It was found that one sharp TDS peak appeared at a temperature around 410 K depending on the heating rate that ranged from 1.5 to 20 K/min. The TDS peak height increased with increasing fluence from 2 × 1019 to 2 × 1021 D+/m2 with no shift of the peak temperature. A close correlation between these TDS peaks and the disappearance of dislocation loops formed by the irradiation was observed. The effects of tiny bubbles on TDS were small. These results suggest that most of the deuterium was trapped by dislocation loops, which affected the thermal stability of dislocation loops in the alloy. The dependence of TDS peak temperature on the heating rate yielded an activation energy of 0.63 ± 0.02 eV for deuterium de-trapping from dislocation loops. The retention properties of the total amount of deuterium exhibited a tendency of saturation at values on the order of 1020 D+/m2, which corresponded to a saturation tendency of the loop density.