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Sample records for calcium 44 reactions

  1. An attempt of application of short lived 44K activity induced in the 44Ca(n,p)44K reaction using 14 MeV neutrons for total body calcium assessment in human subject

    International Nuclear Information System (INIS)

    The status of in vivo neutron activation analysis techniques for the measurement of total body calcium in human subject is reviewed. Relevant data on the nuclear characteristics of calcium isotopes during interaction with neutrons ranging from slow up to 14 MeV neutrons are presented. Physical aspects of the measurement of in vivo total body calcium (TBCa) using 44K activity induced in the 44Ca(n,p)44K(T1/2=22.3 min) reaction by 14 MeV neutrons are discussed. The measurement of delayed γ-ray emitted during decay of activities induced in enriched 44Ca, natCa, phantom filled with water solution of natural calcium and skeletal arm are considered. Results of measurements on the phantom and skeletal arm indicate a possibility to measure the TBCa using the 44K activity. (author)

  2. Limestone reaction in calcium aluminate cement–calcium sulfate systems

    International Nuclear Information System (INIS)

    This paper reports a study of ternary blends composed of calcium aluminate cement, calcium sulfate hemihydrate and limestone. Compressive strength tests and hydration kinetics were studied as a function of limestone and calcium sulfate content. The phase evolution and the total porosity were followed and compared to thermodynamic simulation to understand the reactions involved and the effect of limestone on these binders. The reaction of limestone leads to the formation of hemicarboaluminate and monocarboaluminate. Increasing the ratio between sulfate and aluminate decreases the extent of limestone reaction

  3. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

    Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

  4. Polymorphs calcium carbonate on temperature reaction

    International Nuclear Information System (INIS)

    Calcium carbonate (CaCO3) has three different crystal polymorphs, which are calcite, aragonite and vaterite. In this study, effect of reaction temperature on polymorphs and crystallite structure of CaCO3 was investigated. X-ray powder diffraction (XRD), fourier transform infrared (FTIR), and variable pressure scanning electron microscope (VPSEM) were used to characterize the obtained CaCO3 particles. The obtained results showed that CaCO3 with different crystal and particle structures can be formed by controlling the temperature during the synthesis process

  5. Microphotochemistry: 4,4'-Dimethoxybenzophenone mediated photodecarboxylation reactions involving phthalimides

    Directory of Open Access Journals (Sweden)

    Oksana Shvydkiv

    2011-08-01

    Full Text Available A series of 4,4'-dimethoxybenzophenone mediated intra- and intermolecular photodecarboxylation reactions involving phthalimides have been examined under microflow conditions. Conversion rates, isolated yields and chemoselectivities were compared to analogous reactions in a batch photoreactor. In all cases investigated, the microreactions gave superior results thus proving the superiority of microphotochemistry over conventional technologies.

  6. Production of scandium-44 m and scandium-44 g with deuterons on calcium-44: cross section measurements and production yield calculations.

    Science.gov (United States)

    Duchemin, C; Guertin, A; Haddad, F; Michel, N; Métivier, V

    2015-09-01

    HIGHLIGHTS • Production of Sc-44 m, Sc-44 g and contaminants. • Experimental values determined using the stacked-foil technique. • Thick-Target production Yield (TTY) calculations. • Comparison with the TALYS code version 1.6.Among the large number of radionuclides of medical interest, Sc-44 is promising for PET imaging. Either the ground-state Sc-44 g or the metastable-state Sc-44 m can be used for such applications, depending on the molecule used as vector. This study compares the production rates of both Sc-44 states, when protons or deuterons are used as projectiles on an enriched Calcium-44 target. This work presents the first set of data for the deuteron route. The results are compared with the TALYS code. The Thick-Target production Yields of Sc-44 m and Sc-44 g are calculated and compared with those for the proton route for three different scenarios: the production of Sc-44 g for conventional PET imaging, its production for the new 3 γ imaging technique developed at the SUBATECH laboratory and the production of a Sc-44 m/Sc-44 g in vivo generator for antibody labelling. PMID:26301533

  7. 44gSc from metal calcium targets for PET

    DEFF Research Database (Denmark)

    Severin, Gregory; Gagnon, K.; Engle, J. W.;

    2012-01-01

    A low-cost and efficient method for producing pre-clinical scale quantities of 44gSc is presented. Production involves proton irradiation of natural unenriched calcium metal followed by rapid separation of radioscandium from the target using hydroxmate functionalized resin.© 2012 American Institu...

  8. Reactions of fly ash with calcium aluminate cement and calcium sulphate

    OpenAIRE

    Fernández Carrasco, Lucía; Vázquez Ramonich, Enric

    2009-01-01

    The hydration processes in the ternary system fly ash/calcium aluminate cement/calcium sulphate (FA/CAC/C$) at 20 °C were investigated; six compositions from the ternary system FA/CAC/C$ were selected for this study. The nature of the reaction products in these pastes were analysed by X-ray diffraction (XRD) and infrared spectroscopy (FTIR). At four days reaction time, the main hydration reaction product in these pastes was ettringite and the samples with major initial CAC presented minor ett...

  9. Diffusion-reaction compromise the polymorphs of precipitated calcium carbonate

    Institute of Scientific and Technical Information of China (English)

    Han Wang; Wenlai Huang; Yongsheng Han

    2013-01-01

    Diffusion is seldom considered by chemists and materialists in the preparation of materials while it plays an important role in the field of chemical engineering.If we look at crystallization at the atomic level,crystal growth in a solution starts from the diffusion of ions to the growing surface followed by the incorporation of ions into its lattice.Diffusion can be a rate determining step for the growth of crystals.In this paper,we take the crystallization of calcium carbonate as an example to illustrate the microscopic processes of diffusion and reaction and their compromising influence on the morphology of the crystals produced.The diffusion effect is studied in a specially designed three-cell reactor.Experiments show that a decrease of diffusion leads to retardation of supersaturation and the formation of a continuous concentration gradient in the reaction cell,thus promoting the formation of cubic calcite particles.The reaction rate is regulated by temperature.Increase of reaction rate favors the formation of needle-like aragonite particles.When diffusion and reaction play joint roles in the reaction system,their compromise dominates the formation of products,leading to a mixture of cubic and needle-like particles with a controllable ratio.Since diffusion and reaction are universal factors in the preparation of materials,the finding of this paper could be helpful in the controlled synthesis of other materials.

  10. Gas desulfurization macrokinetics in the calcium oxide reaction

    International Nuclear Information System (INIS)

    High amounts of sulfur dioxide (SO2) are produced by burning of fossil fuels in air in excess, a pollutant agent which, once reaching the atmosphere, transforms in sulfuric acid . One solution of diminishing the SO2 releases is injection of powder limestone in the oven. The reaction CaCO3 = CaO + CO2 gives rise to porous calcium oxide grains which react with SO2 in the presence of oxygen. As a result, calcium sulphate is formed by the reaction CaO + SO2 + 1/2O2 = CaSO4. This technology is convenient for thermal power plants due to small investments and simple operation. However,the desulfurization degree is reduced and the process kinetics is still unelucidated. In this work, the kinetics of the second reaction is studied by thermogravimetry with CAHN TG-121 device. Conversion-time kinetic diagrams were generated for five granulometric classes of Ca CO3 with an average diameter of 25-900 μm. The measurements were carried out at 973 K - 1173 K and gas flow speeds of 0.023 - 0.0277 m/s. The kinetic parameters of the external mass transfer, solid crust diffusion and chemical reaction were determined. The influence of external mass transfer in all operation conditions is insignificant. The influence of solid crust diffusion is dominant even for the smallest particles (25 μm). Therefore, the process is described by a combined macrokinetics reaction-diffusion model, where the resistance to the diffusion is about 80% of the total resistance. Complementary structure determinations using structural models are required for the solid undergoing the reaction in order to rigorously identify the enhancing factors of the process. (authors)

  11. Modeling of calcium-based sorbent reactions with sulfur dioxide

    Directory of Open Access Journals (Sweden)

    Tomanović Ivan

    2015-01-01

    Full Text Available A mathematical model of calcium sorbent reactions for simulation of sulfur dioxide reduction from pulverized coal combustion fl e gasses is developed, implemented within numerical code and validated against available measurements under controlled conditions. The model attempts to closely resemble reactions of calcination, sintering and sulfation, occurring during the sorbent particles motion in the furnace. The sulfation is based on PSSM (Partially Sintered Spheres Model, coupled with simulated particle calcination and sintering. Complex geometry of the particle is taken into account, with the assumption that it consists of spherical grains in contact with each other. Numerical simulations of drop down tube reactors were performed for both CaCO3 and Ca(OH2 sorbent particles and results were compared with available experimental data from literature. The sorbent reactions model will be further used for simulations of desulfurization reactions in turbulent gas-particle flow under coalcombustion conditions. [Projekat Ministarstva nauke Republike Srbije, br. TR-33018: Increase in energy and ecology efficiency of processes in pulverized coal-fired furnace and optimization of utility steam boiler air preheater by using in-house developed software tools

  12. Study of Cold Potassium Atom - Calcium Ion Reactions

    Science.gov (United States)

    Egodapitiya, Kisra; Gang, Shu; Clark, Robert; Brown, Kenneth

    2016-05-01

    We report on our progress towards constructing a hybrid system for studying reactions between cold Potassium (K) atoms and cold Calcium (Ca+) ions. Ca+ ions will be trapped and Doppler-cooled inside a linear quadrupole ion trap. Cold K atoms will be created inside a magneto optical trap, such that the ion and the atoms are in an overlapping volume. Trapping and re-pumping beams for the Potassium MOT are derived from the same laser with wavelength 766 nm using two acousto optic modulators. The reaction products will be detected using a time-of- flight mass spectrometer that is designed to detect radially ejected ions. The main objective of this experiment is to study the rate coefficients, and identification of reaction channels between cold K atoms and Ca+ ions. Subsequently this setup will be used to study reactions between cold K atoms and sympathetically cooled molecular ions such as CaO+, and to study internal state quenching of molecular ions.

  13. Preparation of Phenolized Calcium Lignosulfonate andCharacterization of the Reaction by IR Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A kind of calcium lignosulfonate was phenolized by phenol with sulfuric acid as catalyst. The calcium lignosulfonate and its phenolized derivatives were characterized by infrared spectroscopy. It is proved that the extent and type of the phenolizing reaction can be deduced from the IR spectra of the calcium lignosulfonate and its phenolized derivatives.

  14. The reductive decomposition of calcium sulphate I. Kinetics of the apparent solid-solid reaction

    NARCIS (Netherlands)

    Kamphuis, B.; Potma, A.W.; Prins, W.; Swaaij, van W.P.M.

    1992-01-01

    The reductive decomposition of calcium sulphate by hydrogen is used for the regeneration of calcium-based atmospheric fluidized bed combustion (AFBC) SO2 sorbents. The apparent solid¿solid reaction between CaS and CaSO4, one of the steps involved in the reaction mechanism of the reductive decomposit

  15. Hot fusion-evaporation cross sections of 44Ca-induced reactions with lanthanide targets

    Science.gov (United States)

    Werke, T. A.; Mayorov, D. A.; Alfonso, M. C.; Tereshatov, E. E.; Folden, C. M.

    2015-11-01

    Background: Previously reported cross sections of 45Sc-induced reactions with lanthanide targets are much smaller than 48Ca-induced reactions on the same targets. 44Ca is one proton removed from 45Sc and could be used to produce nuclei with a relative neutron content between those produced in the 45Sc- and 48Ca-induced reactions. Purpose: As part of a systematic investigation of fusion-evaporation reactions, cross sections of 44Ca-induced reactions on lanthanide targets were measured. These results are compared to available data for 48Ca- and 45Sc-induced fusion-evaporation cross sections on the same lanthanide targets. Collectively, these data provide insight into the importance of the survival against fission of excited compound nuclei produced near spherical shell closures. Methods: A beam of 6+Ca at an energy of ≈5 MeV /u was delivered by the K500 superconducting cyclotron at the Cyclotron Institute at Texas A&M University. The desired evaporation residues were selected by the Momentum Achromat Recoil Spectrometer and identified via their characteristic α -decay energies. Excitation functions for the 44Ca+158Gd ,159Tb, and 162Dy reactions were measured at five or more energies each. A theoretical model was employed to study the fusion-evaporation process. Results: The 44Ca-induced reactions have x n cross sections that are two orders of magnitude larger than 45Sc-induced reactions but two orders of magnitude smaller than 48Ca-induced reactions on the same targets. Proton emission competes effectively with neutron emission for the 44Ca+159Tb and 162Dy reactions. The maximum 4 n cross sections in the 44Ca+158Gd ,159Tb, and 162Dy reactions were 2100 ± 230 ,230 ± 20 , and 130 ±20 μ b , respectively. The 44Ca+158Gd and 159Tb cross sections are in good agreement with the respective cross bombardments of 48Ca+154Gd and 45Sc+158Gd once differences in capture cross sections and compound nucleus formation probabilities are corrected for. Conclusions: Excitation

  16. Spectroscopic study of 44Ti by reactions 40Ca(α,γ)44Ti, 40Ca(7Li,p2nγ)44Ti and 42Ca(α,2nγ)44Ti

    International Nuclear Information System (INIS)

    The first reaction allowed to populate states of excitation energies between 9.2 and 9.8 MeV and to measure their γ-decays to low-lying states in 44Ti. Moreover this reaction helps in measuring the mean lifetime of 12 states by using the Doppler shift attenuation method. The second reaction was used to find the levels predicted by the shell model and among them the highest spin allowed Jsup(π)=12+. The third reaction helps in measuring the mean lifetime tau=3.0+-0.6 ns of the Jsup(π)=(12+) state at Esub(x)=8.040 MeV. In this measurement the delayed coincidence technique with a pulsed beam was used. A confrontation of the experimental and theoretical studies on the 44Ti nucleus is presented in this work

  17. Separation of cyclotron-produced 44Sc from a natural calcium target using a dipentyl pentylphosphonate functionalized extraction resin

    Science.gov (United States)

    Valdovinos, H.F.; Hernandez, R.; Barnhart, T.E.; Graves, S.; Cai, W.; Nickles, R.J.

    2014-01-01

    Significant interest in 44Sc as a radioactive synthon to label small molecules for positron emission tomography (PET) imaging has been recently observed. Despite the efforts of several research groups, the ideal 44Sc production and separation method remains elusive. Herein, we propose a novel separation method to obtain 44Sc from the proton irradiation of calcium targets based on extraction chromatography, which promises to greatly simplify current production methodologies. Using the commercially available Uranium and Tetravalent Actinides (UTEVA) extraction resin we were able to rapidly ( 80% of the activity generated at end of bombardment (EoB) in small ~1 M HCl fractions (400 μL). The chemical purity of the 44Sc eluates was evaluated through chelation with DOTA and DTPA, and by trace metal analysis using microwave induced plasma atomic emission spectrometry. The distribution coefficients (Kd) of Sc(III) and Ca(II) in UTEVA were determined in HCl medium in a range of concentrations from zero to 12.1 M The 44Sc obtained with our method proved to be suitable for the direct labeling of small biomolecules for PET imaging, with excellent specific activities and radiochemical purity. PMID:25464172

  18. Synthesis and reaction behavior of calcium silicate hydrate in basic system

    Institute of Scientific and Technical Information of China (English)

    刘桂华; 贺强; 李小斌; 彭志宏; 周秋生

    2004-01-01

    At the molar ratio of CaO to SiO2 of 1, with calcium hydroxide and sodium silicate, calcium silicate hydrate was synthesized at 50, 100, 170 ℃, respectively. The results show that temperature favors the formation of calcium silicate hydrate with perfect structure. When calcium silicate hydrate reacts with caustic solution, the decomposition rate of calcium silicate hydrate increases with the increasing caustic concentration and decreases with the raising synthesis temperature and the prolongation of reaction time. The decomposition rate is all less than 1.2 % in caustic solution, and XRD pattern of the residue after reaction with caustic solution is found as the same as that of original calcium silicate hydrate, which indicates the stable existence of calcium silicate hydrate in caustic solution.When reacted with soda solution, the decomposition rate increases with the increasing soda concentration and reaction time, while decreases with the synthesis temperature. The decomposition rate is more than 2% because CaO · SiO2 · H2O(CSH( Ⅰ )), except Ca5 (OH)2Si6O16 · 4H2O and Ca6Si6O17 (OH)2, is decomposed. So the synthesis temperature and soda concentration should be controlled in the process of transformation of sodium aluminosilicate hydrate into calcium silicate hydrate.

  19. Study of calcium solid phase reactions with terbium and scandium fluorides and oxygen mixtures

    International Nuclear Information System (INIS)

    The interaction of calcium with TbF3-Tb2O3 and ScF3-Sc2O3 binary mixtures is investigated using the method of isothermal kinetics and thermogravimetry. It is revealed that the curve of calcium reaction rate depending on the composition of fluoride-oxide mixture has an extremum, the position of the extremum shifting to the side of more inert oxides

  20. Measurement of the $^{44}$Ti($\\alpha$,p)$^{47}$V reaction cross section, of relevance to $\\gamma$-ray observation of core collapse supernovae, using reclaimed $^{44}$Ti

    CERN Multimedia

    Despite decades of research, fundamental uncertainties remain in the underlying explosion mechanism of core collapse supernovae. One of the most direct methods that might help resolve this problem is a comparison of the predicted to the observed flux of $\\gamma$-rays due to decay of $^{44}$Ti produced in the explosion, as it is believed this could reveal the location of the mass cut, a key hydrodynamical property of the explosion. Such a study is at present limited by the uncertainty in the $^{44}$Ti($\\alpha$,p)$^{47}$V reaction rate. In this experiment we propose to measure the cross section for this reaction at astrophysically relevant energies. The single previous measurement of this reaction was limited to higher energies due to low beam intensities. Here, a more intense beam will be employed, generated from $^{44}$Ti reclaimed as part of the ERAWAST project at PSI.

  1. Effect of temperature on kinetic parameters of decomposition reaction of calcium carbonate

    Institute of Scientific and Technical Information of China (English)

    CHEN Hongwei; CHEN Jiangtao; WEI Riguang; SUO Xinliang

    2013-01-01

    In order to investigate the influence of temperature on behavior of calcium carbonate decomposition,especially on kinetic parameters of the decomposition reaction,the analytically pure calcium carbonate was calcined on a self-built large dose thermogravimetric analyzer.The results indicated that,with an increase in the reaction temperature,the reactivity index of calcium carbonate decomposition increased at stage state while the kinetic parameters decreased at stage state.Moreover,both the reaction indices and the kinetic parameters can be divided into three stages and the temperature turning points in different stages were the same.The phase boundary reaction (cylindrical symmetry) theory was more suitable for calcium carbonate calcination under N2 atmosphere.The change trend of the logarithm of reaction activation with temperature was similar as that of the pre-exponential factor.There existed good liner relationship and kinetic compensation effect between them.The isokinetic temperature of the CaCO3 calcination was 842 ℃ and the reaction rate constant was 0.104 9 min-1 derived by the compensation coefficients.

  2. Ion microscopic imaging of calcium transport in the intestinal tissue of vitamin D-deficient and vitamin D-replete chickens: A 44Ca stable isotope study

    International Nuclear Information System (INIS)

    The intestinal absorption of calcium includes at least three definable steps; transfer across the microvillar membrane, movement through the cytosolic compartment, and energy-dependent extrusion into the lamina propria, Tracing the movement of calcium through the epithelium has been hampered by lack of suitable techniques and, in this study, advantage was taken of ion microscopy in conjunction with cryosectioning and use of the stable isotope 44Ca to visualize calcium in transit during the absorptive process. The effect of vitamin D, required for optimal calcium absorption, was investigated. Twenty millimolar 44Ca was injected into the duodenal lumen in situ of vitamin D-deficient and vitamin D-replete chickens. At 2.5, 5.0, and 20.0 min after injection, duodenal tissue was obtained and processed for ion microscopic imaging. At 2.5 min. 44Ca was seen to be concentrated in the region subjacent to the microvillar membrane in tissue from both groups. At 5.0 and 20.0 min, a similar pattern of localization was evident in D-deficient tissues. In D-replete tissues, the distribution of 44Ca became more homogenous, indicating that vitamin D increased the rate of transfer of Ca2+ from the apical to the basolateral membrane, a function previously ascribed to the vitamin D-induced calcium-binding protein (28-kDa calbindin-D). Quantitative aspects of the calcium absorptive process were determined in parallel experiments with the radionuclide 47Ca. Complementary information on the localization of the naturally occurring isotopes of calcium (40Ca) and potassium (39K) is also described

  3. Pressure induced reactions amongst calcium aluminate hydrate phases

    KAUST Repository

    Moon, Ju-hyuk

    2011-06-01

    The compressibilities of two AFm phases (strätlingite and calcium hemicarboaluminate hydrate) and hydrogarnet were obtained up to 5 GPa by using synchrotron high-pressure X-ray powder diffraction with a diamond anvil cell. The AFm phases show abrupt volume contraction regardless of the molecular size of the pressure-transmitting media. This volume discontinuity could be associated to a structural transition or to the movement of the weakly bound interlayer water molecules in the AFm structure. The experimental results seem to indicate that the pressure-induced dehydration is the dominant mechanism especially with hygroscopic pressure medium. The Birch-Murnaghan equation of state was used to compute the bulk modulus of the minerals. Due to the discontinuity in the pressure-volume diagram, a two stage bulk modulus of each AFm phase was calculated. The abnormal volume compressibility for the AFm phases caused a significant change to their bulk modulus. The reliability of this experiment is verified by comparing the bulk modulus of hydrogarnet with previous studies. © 2011 Elsevier Ltd. All rights reserved.

  4. Consumers’ Health-Related Motive Orientations and Reactions to Claims about Dietary Calcium

    Directory of Open Access Journals (Sweden)

    Christine Hoefkens

    2013-01-01

    Full Text Available Health claims may contribute to better informed and healthier food choices and to improved industrial competitiveness by marketing foods that support healthier lifestyles in line with consumer preferences. With the more stringent European Union regulation of nutrition and health claims, insights into consumers’ health-related goal patterns and their reactions towards such claims are needed to influence the content of lawful claims. This study investigated how consumers’ explicit and implicit health-related motive orientations (HRMOs together with the type of calcium-claim (nutrition claim, health claim and reduction of disease risk claim influence perceived credibility and purchasing intention of calcium-enriched fruit juice. Data were collected in April 2006 through a consumer survey with 341 Belgian adults. The findings indicate that stronger implicit HRMOs (i.e., indirect benefits of calcium for personal health are associated with higher perceived credibility, which is not (yet translated into a higher purchasing intention. Consumers’ explicit HRMOs, which refer to direct benefits or physiological functions of calcium in the body — as legally permitted in current calcium-claims in the EU — do not associate with reactions to the claims. Independently of consumers’ HRMOs, the claim type significantly affects the perceived credibility and purchasing intention of the product. Implications for nutrition policy makers and food industries are discussed.

  5. Consumers’ health-related motive orientations and reactions to claims about dietary calcium.

    Science.gov (United States)

    Hoefkens, Christine; Verbeke, Wim

    2013-01-01

    Health claims may contribute to better informed and healthier food choices and to improved industrial competitiveness by marketing foods that support healthier lifestyles in line with consumer preferences. With the more stringent European Union regulation of nutrition and health claims, insights into consumers' health-related goal patterns and their reactions towards such claims are needed to influence the content of lawful claims. This study investigated how consumers' explicit and implicit health-related motive orientations (HRMOs) together with the type of calcium-claim (nutrition claim, health claim and reduction of disease risk claim) influence perceived credibility and purchasing intention of calcium-enriched fruit juice. Data were collected in April 2006 through a consumer survey with 341 Belgian adults. The findings indicate that stronger implicit HRMOs (i.e., indirect benefits of calcium for personal health) are associated with higher perceived credibility, which is not (yet) translated into a higher purchasing intention. Consumers' explicit HRMOs, which refer to direct benefits or physiological functions of calcium in the body-as legally permitted in current calcium-claims in the EU-do not associate with reactions to the claims. Independently of consumers' HRMOs, the claim type significantly affects the perceived credibility and purchasing intention of the product. Implications for nutrition policy makers and food industries are discussed. PMID:23306190

  6. Synthesis of Calcium(II) Amidinate Precursors for Atomic Layer Deposition through a Redox Reaction between Calcium and Amidines.

    Science.gov (United States)

    Kim, Sang Bok; Yang, Chuanxi; Powers, Tamara; Davis, Luke M; Lou, Xiabing; Gordon, Roy G

    2016-08-22

    We have prepared two new Ca(II) amidinates, which comprise a new class of ALD precursors. The syntheses proceed by a direct reaction between Ca metal and the amidine ligands in the presence of ammonia. Bis(N,N'-diisopropylformamidinato)calcium(II) (1) and bis(N,N'-diisopropylacetamidinato)calcium(II) (2) adopt dimeric structures in solution and in the solid state. X-ray crystallography revealed asymmetry in one of the bridging ligands to afford the structure [(η(2) -L)Ca(μ-η(2) :η(2) -L)(μ-η(2) :η(1) -L)Ca(η(2) -L)]. These amidinate complexes showed unprecedentedly high volatility as compared to the widely employed and commercially available Ca(II) precursor, [Ca3 (tmhd)6 ]. In CaS ALD with 1 and H2 S, the ALD window was approximately two times wider and lower in temperature by about 150 °C than previously reported with [Ca3 (tmhd)6 ] and H2 S. Complexes 1 and 2, with their excellent volatility and thermal stability (up to at least 350 °C), are the first homoleptic Ca(II) amidinates suitable for use as ALD precursors. PMID:27351794

  7. Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Jepson, B.E.; Shockey, G.C.

    1984-01-01

    The enrichment of calcium isotopes has been observed in ion-exchange chromatography with an aqueous phase of calcium hydroxide and a solid phase of sulfonic acid resin. The band front was exceedingly sharp as a result of the acid-base reaction occuring at the front of the band. Single-stage separation coefficients were found to be epsilon(/sup 44/Ca//sup 40/Ca) = 11 x 10 /sup -4/ and epsilon(/sup 48/Ca//sup 40/Ca) = 18 x 10/sup -4/. The maximum column separation factors achieved were 1.05 for calcium-44 and 1.09 for calcium-48 with the heavy isotopes enriching in the fluid phase. The calcium isotope effect between fully hydrated aqueous calcium ions and undissociated aqueous calcium hydroxide was estimated. For the calcium-44/40 isotope pair the separation coefficient was 13 x 10/sup -4/. 20 references, 2 figures.

  8. Heterogeneous reactions of gaseous methanesulfonic acid with calcium carbonate and kaolinite particles

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Heterogeneous reactions of gaseous methanesulfonic acid (MSA) with calcium carbonate (CaCO3) and kaolinite particles at room temperature were investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion chromatography (IC).Methanesulfonate (MS-) was identified as the product in the condensed phase,in accordance with the product of the reaction of gaseous MSA with NaCl and sea salt particles.When the concentration of gaseous MSA was 1.34 × 10-13 molecules cm-3,the uptake coefficient was (1.21 ± 0.06) × 10-8 (1) for the reaction of gaseous MSA with CaCO3 and (4.10 ± 0.65) × 10 10 (1) for the reaction with kaolinite.Both uptake coefficients were significantly smaller than those of the reactions of gaseous MSA with NaCl and sea salt particles.

  9. A novel microwave synthesis of calcium hydroxyapatite. Optimisation and investigation of a microwave assisted reaction route

    International Nuclear Information System (INIS)

    Hydroxyapatite is a bioactive calcium phosphate used in non-load bearing applications, such as space-filling in maxillofacial reconstruction. As a coating, hydroxyapatite is used on load-bearing orthopaedic metal prostheses to improve fixation and/or biocompatibility. Conventional synthesis processes for the production of hydroxyapatite are time-consuming and labour-intensive. Microwave irradiation was investigated as a means to enhance the synthesis reaction using calcium hydroxide (Ca(OH)2) and orthophosphoric acid (H3PO4) as reactants. An initial set of reactions indicated the feasibility of the microwave synthesis route. Optimisation reactions were then performed followed by investigation sets of reactions. Parameters such as microwave power, irradiation time, and reactant concentrations were varied. Using 0.5M Ca(OH)2 and 0.3M H3PO4, a phase-pure hydroxyapatite powder with a stoichiometric molar Ca/P ratio of 1.67 was produced in 60 seconds at 450W and 2.45GHz. The microwave synthesis reaction only reached completion when conducted at moderate temperatures (20-30 deg C). At approximately 5 deg C and at temperatures in excess of 45 deg C, the microwave reaction did not reach completion. A preliminary kinetic study of the microwave reaction revealed a 3 to 4-fold increase in the activation energy of the microwave reaction compared to a non-microwave equivalent. The Arrhenius pro-exponential factor was half that of the non-microwave reaction. The kinetic data suggests two energetically different pathways for the reaction between Ca(OH)2 and H3PO4. A fast high-energy pathway is powered by microwave irradiation, while a slow low-energy pathway prevails under conventional synthesis conditions. Microwave synthesis has potential for scaling-up to commercial amounts of hydroxyapatite powder production. Control over the product powder morphology may be achieved with further optimisation. (author)

  10. Study of the {sup 44}Ti(α,p){sup 47}V reaction and implications for core collapse supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Margerin, V., E-mail: vincent.margerin@ed.ac.uk [School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom); Murphy, A.St.J.; Davinson, T. [School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom); Dressler, R. [Laboratory of Radiochemistry and Environmental Chemistry, Paul Scherrer Institut, CH-5232 (Switzerland); Fallis, J. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Kankainen, A. [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä (Finland); Helsinki Institute of Physics, P.O. Box 64, FI-00014 University of Helsinki (Finland); Laird, A.M. [Department of Physics, University of York, York, YO10 5DD (United Kingdom); Lotay, G.; Mountford, D.J.; Murphy, C.D. [School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom); Seiffert, C. [CERN (Organisation Européenne pour la Recherche Nucléaire), CH-1211 Genève 23 (Switzerland); Schumann, D.; Stowasser, T. [Laboratory of Radiochemistry and Environmental Chemistry, Paul Scherrer Institut, CH-5232 (Switzerland); Stora, T. [CERN (Organisation Européenne pour la Recherche Nucléaire), CH-1211 Genève 23 (Switzerland); Wang, C.H.-T. [Department of Physics, Aberdeen University, Aberdeen, AB24 3UE (United Kingdom); Woods, P.J. [School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom)

    2014-04-04

    The underlying physics triggering core collapse supernovae is not fully understood but observations of material ejected during such events helps to solve this puzzle. In particular, several satellite based γ-ray observations of the isotope {sup 44}Ti have been reported recently. Conveniently, the amount of this isotope in stellar ejecta is thought to depend critically on the explosion mechanism. The most influential reaction to the amount of {sup 44}Ti in supernovae is {sup 44}Ti(α,p){sup 47}V. Here we report on a direct study of this reaction conducted at the REX-ISOLDE facility, CERN. The experiment was performed with a {sup 44}Ti beam at E{sub lab}=2.16 MeV/u, corresponding to an energy distribution, for reacting α-particles, centred on E{sub cm}=4.15 with a 1σ width of 0.23 MeV. This is, for the first time, well within the Gamow window for core collapse supernovae. The material from which the {sup 44}Ti beam was extracted originates from highly irradiated components of the SINQ spallation neutron source of the Paul Scherrer Institute. No yield above background was observed, enabling an upper limit for the rate of this reaction to be determined. This result is below expectation, suggesting that the {sup 44}Ti(α,p){sup 47}V reaction proceeds more slowly than previously thought. Implications for astrophysical events, and remnant age, are discussed.

  11. Study of the 44Ti(α,p)47V reaction and implications for core collapse supernovae

    International Nuclear Information System (INIS)

    The underlying physics triggering core collapse supernovae is not fully understood but observations of material ejected during such events helps to solve this puzzle. In particular, several satellite based γ-ray observations of the isotope 44Ti have been reported recently. Conveniently, the amount of this isotope in stellar ejecta is thought to depend critically on the explosion mechanism. The most influential reaction to the amount of 44Ti in supernovae is 44Ti(α,p)47V. Here we report on a direct study of this reaction conducted at the REX-ISOLDE facility, CERN. The experiment was performed with a 44Ti beam at Elab=2.16 MeV/u, corresponding to an energy distribution, for reacting α-particles, centred on Ecm=4.15 with a 1σ width of 0.23 MeV. This is, for the first time, well within the Gamow window for core collapse supernovae. The material from which the 44Ti beam was extracted originates from highly irradiated components of the SINQ spallation neutron source of the Paul Scherrer Institute. No yield above background was observed, enabling an upper limit for the rate of this reaction to be determined. This result is below expectation, suggesting that the 44Ti(α,p)47V reaction proceeds more slowly than previously thought. Implications for astrophysical events, and remnant age, are discussed.

  12. Cross-sections of 14 MeV neutron reactions on phosphorus and calcium

    International Nuclear Information System (INIS)

    Cross-section values for 14.7 MeV neutrons are measured for the following reactions: 31P(n, α)28Al, (132+-10) mb; 42Ca(n, p)42K, (173+-19) mb; 43Ca(n, p)43K, (111+-9) mb; 44Ca(n, p)44K, (42+-2) mb; 44Ca(n, α)41Ar, (27+-2) mb; 48Ca(n, 2n)47Ca, (616+-54) mb. The preferred mean values for each reaction are given. The 27Al(n, p)27Mg reaction is used as a reference reaction the cross-section of which is taken as σsub(r)=75 mb, while the half-life of 27Mg is T=9.45 m. This reaction is suitable for short-lived activities arising in the different reactions. For long-lived activities the 27Al(n, α)24Na (T=15 h) reaction is used as a standard. The cross-section for this reaction was selected using the good agreement of mean values given in earlier reports. The samples were irradiated in the SAMES neutron generator which produces 14 MeV neutrons by the 3H(d, n)4He reaction. A rotating target assembly was used to provide stable neutron yields, which were monitored and registered so that it was possible to deduce PHIsub(corr)-terms when necessary. Measurements of the spectra were performed with a 110 cm3 Ge(Li) detector on line with a PDP-9 computer. The peak analyses of the spectra were performed with the aid of the VIPUNEN program on a Burroughs 6700 computer. (T.G.)

  13. A novel microwave synthesis of calcium hydroxyapatite. Optimisation and investigation of a microwave assisted reaction route

    CERN Document Server

    Zawahreh, Y

    2001-01-01

    Hydroxyapatite is a bioactive calcium phosphate used in non-load bearing applications, such as space-filling in maxillofacial reconstruction. As a coating, hydroxyapatite is used on load-bearing orthopaedic metal prostheses to improve fixation and/or biocompatibility. Conventional synthesis processes for the production of hydroxyapatite are time-consuming and labour-intensive. Microwave irradiation was investigated as a means to enhance the synthesis reaction using calcium hydroxide (Ca(OH) sub 2) and orthophosphoric acid (H sub 3 PO sub 4) as reactants. An initial set of reactions indicated the feasibility of the microwave synthesis route. Optimisation reactions were then performed followed by investigation sets of reactions. Parameters such as microwave power, irradiation time, and reactant concentrations were varied. Using 0.5M Ca(OH) sub 2 and 0.3M H sub 3 PO sub 4 , a phase-pure hydroxyapatite powder with a stoichiometric molar Ca/P ratio of 1.67 was produced in 60 seconds at 450W and 2.45GHz. The microw...

  14. Formation cross sections of 43Sc, 44Sc and 46Sc isotopes in the 45Sc + 3He reaction

    International Nuclear Information System (INIS)

    In the experiments performed on the 3He-ion beam irradiation scandium targets at the U-120M cyclotron of the Institute of Nuclear Physics of the Czech Academy of Sciences, Rez, 45Sc(3He, αn)43Sc, 45Sc(3He,α)44Sc and 45Sc(3He, 2p)46Sc reactions were investigated in the 3He energy range from 5 to 24 MeV. To determine the yield of resulting Sc isotope, activation technique was used. A measurement of γ-activity induced in the target was carried out using HPGe-detector of high resolution. Despite the low binding energy of 3He and positive values of Q-reactions leading to the formation of 44Sc and 46Sc isotopes, the behavior of excitation functions for the formation of these isotopes is different from the behavior of excitation functions for deuterons. Cross sections for 44Sc reach their maximum at the Coulomb barrier of the reaction. This is due to the fact that the stable core of 4He forms in the reaction in addition to 44Sc

  15. Continuous reaction crystallization of struvite from phosphate(V) solutions containing calcium ions

    Energy Technology Data Exchange (ETDEWEB)

    Hutnik, N.; Wierzbowska, B.; Matynia, A. [Wroclaw University of Technology, Faculty of Chemistry, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Piotrowski, K. [Silesian University of Technology, Department of Chemical and Process Engineering, ks. M. Strzody 7, 44-101 Gliwice (Poland)

    2011-05-15

    Continuous reaction crystallization of struvite from water solutions containing phosphate(V) (1.0 mass%) and calcium ions (from 0.01 to 0.20 mass%) was investigated. Process was carried out in temperature 298 K in continuous DT MSMPR type crystallizer with internal circulation of suspension. Influence of pH (from 9 to 11) and mean residence time of suspension in crystallizer (from 900 to 3600 s) on product crystal size distribution, mean size, population homogeneity and shape of crystals, as well as chemical composition of solid phase was tested. Within the investigated process parameter ranges struvite crystals of mean size from 18 to ca. 50 {mu}m were produced. With the increase in calcium ions concentration in a feed mean crystal size decreased from 34.2 to 18.4 {mu}m (pH 9, {tau} 900 s). Coexistence of struvite and hydroxyapatite crystals in the solid product was confirmed analytically (Ca content in solid product from 0.3 to 8.4 mass%). Presence of calcium ions favoured crystallization of struvite in a form of tubular crystals, characterized by lengthwise cracks and irregular edges. Co-precipitated hydroxyapatite particles showed relatively small sizes, even below 1 {mu}m, forming agglomerates on the surface of larger struvite crystals and individual agglomerates. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Study of the $^{44}$Ti$(\\alpha,p)^{47}$V47 reaction and implications for core collapse supernovae

    CERN Document Server

    Margerin, V; Davinson, T; Dressler, R; Fallis, J; Kankainen, A; Laird, A M; Lotay, G; Mountford, D J; Murphy, C D; Seiffert, C; Schumann, D; Stowasser, T; Stora, T; Wang, C H -T; Woods, P J

    2014-01-01

    The underlying physics triggering core collapse supernovae is not fully understood but observations of material ejected during such events helps to solve this puzzle. In particular, several satellite based γ -ray observations of the isotope 44 Ti have been reported recently. Conveniently, the amount of this isotope in stellar ejecta is thought to depend critically on the explosion mechanism. The most influential reaction to the amount of 44 Ti in supernovae is 44 Ti ( α , p ) 47 V. Here we report on a direct study of this reaction conducted at the REX-ISOLDE facility, CERN. The experiment was performed with a 44 Ti beam at E lab = 2 . 16 MeV / u, corresponding to an energy distribution, for reacting α -particles, centred on E cm = 4 . 15 with a 1 σ width of 0.23 MeV. This is, for the first time, well within the Gamow window for core collapse supernovae. The material from which the 44 Ti beam was extracted originates from highly irradiated components of the SINQ spallation neutron source of the Paul Scherr...

  17. Calcium-Magnesium-Aluminosilicate (CMAS) Reactions and Degradation Mechanisms of Advanced Environmental Barrier Coatings

    Science.gov (United States)

    Ahlborg, Nadia L.; Zhu, Dongming

    2013-01-01

    The thermochemical reactions between calcium-magnesium-aluminosilicate- (CMAS-) based road sand and several advanced turbine engine environmental barrier coating (EBC) materials were studied. The phase stability, reaction kinetics and degradation mechanisms of rare earth (RE)-silicates Yb2SiO5, Y2Si2O7, and RE-oxide doped HfO2 and ZrO2 under the CMAS infiltration condition at 1500 C were investigated, and the microstructure and phase characteristics of CMAS-EBC specimens were examined using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Experimental results showed that the CMAS dissolved RE-silicates to form crystalline, highly non-stoichiometric apatite phases, and in particular attacking the silicate grain boundaries. Cross-section images show that the CMAS reacted with specimens and deeply penetrated into the EBC grain boundaries and formed extensive low-melting eutectic phases, causing grain boundary recession with increasing testing time in the silicate materials. The preliminary results also showed that CMAS reactions also formed low melting grain boundary phases in the higher concentration RE-oxide doped HfO2 systems. The effect of the test temperature on CMAS reactions of the EBC materials will also be discussed. The faster diffusion exhibited by apatite and RE-doped oxide phases and the formation of extensive grain boundary low-melting phases may limit the CMAS resistance of some of the environmental barrier coatings at high temperatures.

  18. Genetic variant in CD44 confer susceptibility to acute skin reaction in breast cancer patients undergoing radiotherapy

    International Nuclear Information System (INIS)

    Heterogeneity in toxicity to normal tissue is observed in 10% of cancer patients after radiotherapy (RT) which limits the therapeutic outcome. Response to RT is manifested from alterations in gene of vivid pathways involving DNA damage-repair, inflammatory cytokine, cell cycle regulation, antioxidant response etc. Therefore, the common sequence variants in these radioresponsive genes may modify the severity of normal tissue toxicity and identification of the same may have clinical relevance as a predictive biomarker. The present study was aimed to evaluate the potential modifying role of genetic variants in NFE2L2, OGG1, NEIL3, RAD17, PTTG1, REV3L, ALAD, CD44, RAD9A, LIG3, SH3GL1, BAXS, XRCC1, MAD2L2 and TGFBR3 on the individual susceptibility to RT induced acute skin reactions. All the 132 breast cancer patients were treated with a total dose of 50 Gy in case of mastectomy and 60 Gy in breast conservation surgery. The severity of skin damage was scored according to the Radiation Therapy Oncology Group (RTOG) criteria and the toxicity scores were dichotomized as non-over-responders (NOR; RTOG<2) and over-responders (NOR;RTOG>2) for analysis. Out of the 132 subjects, 44 were ORs. Among the 20 studied SNPs of indicated genes, the rs8193 (CD44) polymorphism lying in the miRNA binding site was significantly (p<0.05) associated with the RT induced adverse skin reactions. The non-coding CD44 3'-UTR serves as a competitor for miRNA binding and subsequently inactivates miRNA functions, by freeing the target mRNAs from being repressed. Therefore, though the role of CD44 in radiosensitivity is unknown, the change in the miRNA binding to CD44mRNA transcripts may regulate expression of several genes involved in pathophysiology of normal tissue radiosensitivity leading to the observed outcome. (author)

  19. Role of calcium and calmodulin in reaction of gastric fundus contraction

    Directory of Open Access Journals (Sweden)

    Marta Gajdus

    2011-09-01

    Full Text Available Background:The subject of this study is determination of the influence of calmodulin and calcium on gastric fundus smooth muscle contraction. During experiments, the author tested the influence of a serotonin receptor agonist, serotonin (5-HT, causing smooth muscle contraction.Material/Methods:Testing was conducted on tissues isolated from rat’s stomach. Male Wistar rats with weight between 220 g and 360 g were anesthetized by intraperitoneal injection of urethane (120 mg/kg. The stomach was dissected, and later the gastric fundus was isolated. Tissue was placed in a dish for insulated organs with 20 ml in capacity, filled with Krebs fluid. Results contained in the study are average values ± SE. In order to determine statistical significance, the principles of receptor theory were used (Kenakin modification.Results:According to conducted tests, we can deduce that 8 Br cGMP stops the reaction of gastric fundus smooth muscle contraction induced by serotonin. The use of 8Br-cGMP in the range of concentrations between 10 and 300 µM leads to reduction of maximum effect from 100�0to 46�20Similar changes were obtained after the use of guanylate cyclase activator (CG – YC-1. Curves for the contractile activity of serotonin along with an increase of concentration YC-1 are shifted to the right, and the maximum effect of reaction decreases. Increasing concentrations of flunarizine, a calmodulin antagonist, in a concentration-dependent way blocks binding between calcium and calmodulin, and at the same time leads to the shift of concentration-effect curves for serotonin to the right and a decrease of maximum reaction.Increasing concentrations of ODQ, a guanylate cyclase inhibitor lead to statistically significant shift of the curves to the left, decrease of EC50 value and simultaneous increase of maximum reaction to serotonin.Conclusions:According to conducted testing, serotonin causes gastric fundus smooth muscle contraction dependent on

  20. Analysis of the normal optical, Michel and molecular potentials on the $^{40}$Ca($^6$Li, d)$^{44}$ Ti reaction

    Indian Academy of Sciences (India)

    MAZUMDER UTTAM K; SOMADDER ANOCK; HOQUE ENAMUL; HAQUE YASMEEN; DAS SUSANTA K; SEN GUPTA H M

    2016-06-01

    Full finite-range (FFR) distorted-wave Born approximation (DWBA) method has been applied to analyse the angular distributions of cross-sections of the $^{40}$Ca($^{6}$Li, d)$^{44}$Ti reaction at 28 MeV incident energy for the 22 transitions involving both the bound and unbound states of $^{44}$Ti byusing the normal optical, Michel and molecular potentials. The extracted spectroscopic factors for the three optical potentials are compared with those of some previous studies of zero-range (ZR) calculations of the$^{40}$Ca($^{6}$Li, d)$^{44}$Ti reaction using the normal optical potential. The $\\chi^{2}$ values of all the levels are obtained for the three optical potentials to estimate the quality of the fits. Molecular and Michel potentials have been used for the first time to analyse the four-nucleon transfer reaction and it seems that the molecular potential fits the experimental data more satisfactorily for some of the states than the normal optical and Michel potentials.

  1. In vitro surface reaction layer formation and dissolution of calcium phosphate cement-bioactive glass composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu Changsheng [Key Laboratory for Ultrafine Materials of Ministry of Education, and Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Chen, C.-W.; Ducheyne, Paul [Center for Bioactive Materials and Tissue Engineering, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 (United States)], E-mail: liucs@ecust.edu.cn, E-mail: ducheyne@seas.upenn.edu

    2008-09-01

    Composites of hydrated calcium phosphate cement (CPC) and bioactive glass (BG) containing Si were immersed in vitro to study the effect of chemical composition on surface reaction layer formation and dissolution/precipitation behavior. The solutions used were 0.05 M tris hydroxymethyl aminomethane/HCl (tris buffer), tris buffer supplemented with plasma electrolyte (TE) with pH 7.4 at 37 deg. C, and this solution complemented with 10% newborn bovine serum (TES). The post-immersion solutions were analyzed for changes in Ca, PO{sub 4} and Si concentrations. The reacted surfaces were analyzed using Fourier transform infrared (FTIR), and scanning electron microscopy with energy dispersive x-ray analysis. The sample weight variations after immersion were also determined. The results showed that the composition of the bioactive composite CPCs greatly affected their behavior in solution and the formation of apatite bioactive surface reaction layers. After immersion in the TE solution, Ca ions were taken up by all samples during the entire immersion duration. Initially, the P ion concentration increased sharply, and then decreased. This reaction pattern reveals the formation of an amorphous calcium phosphate layer on the surface of these composite CPCs. FTIR revealed that the layer was, in fact, poorly crystallized Ca-deficient carbonate apatite. The thickness of the layer was 12-14 {mu}m and it was composed of rod-like apatite with directional arrangement. For immersion in the TES solution, the Ca and Si ion concentrations showed a similar behavior to that in TE, but the release rate of Si ions was higher. FTIR revealed that after TES immersion, not only did the typical, poorly crystallized, Ca-deficient carbonated apatite form, as it did in TE, but also the serum proteins co-adsorbed on the surface and thereby affected the surface reaction layer formation. A thinner apatite layer was formed and was composed of a micro-porous layer comprising rounded particles in a glue

  2. Chemical looping coal gasification with calcium ferrite and barium ferrite via solid--solid reactions

    Energy Technology Data Exchange (ETDEWEB)

    Siriwardane, Ranjani [U.S. Department of Energy/NETL; Riley, Jarrett [Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); Tian, Hanjing [West Virginia Univ., Morgantown, WV (United States); Richards, George [U.S. Department of Energy/NETL

    2016-01-01

    Coal gasification to produce synthesis gas by chemical looping was investigated with two oxygen carriers, barium ferrite (BaFe2O4) and calcium ferrite (CaFe2O4). Thermo-gravimetric analysis (TGA) and fixed-bed flow reactor data indicated that a solid–solid interaction occurred between oxygen carriers and coal to produce synthesis gas. Both thermodynamic analysis and experimental data indicated that BaFe2O4 and CaFe2O4 have high reactivity with coal but have a low reactivity with synthesis gas, which makes them very attractive for the coal gasification process. Adding steam increased the production of hydrogen (H2) and carbon monoxide (CO), but carbon dioxide (CO2) remained low because these oxygen carriers have minimal reactivity with H2 and CO. Therefore, the combined steam–oxygen carrier produced the highest quantity of synthesis gas. It appeared that neither the water–gas shift reaction nor the water splitting reaction promoted additional H2 formation with the oxygen carriers when steam was present. Wyodak coal, which is a sub-bituminous coal, had the best gasification yield with oxygen carrier–steam while Illinois #6 coal had the lowest. The rate of gasification and selectivity for synthesis gas production was significantly higher when these oxygen carriers were present during steam gasification of coal. The rates and synthesis gas yields during the temperature ramps of coal–steam with oxygen carriers were better than with gaseous oxygen.

  3. Emission of complex fragments in the reaction Ar+Au at 44 and 77 A.MeV

    International Nuclear Information System (INIS)

    Complex fragment emission from the 44 and 77 A.MeV 40Ar + 197Au reaction was investigated, and complex fragments have been detected, together with the associated neutron multiplicity distributions, and are seen to be preferentially emitted in violent collisions. Equilibrium and non-equilibrium components were identified which are discussed in terms of statistical emission from the hot target-like fragment and of a possible persistence of a deep-inelastic process. (R.P.) 45 refs.; 16 figs.; 1 tab

  4. Calibration of 44Sc isomer ratio measurements for heavy ion reactions

    International Nuclear Information System (INIS)

    The isomer ratio for the states 6+/2+ was determined in the 29Si(18O, p2n) reaction at 30 to 80 MeV. Experimental and calculated values are plotted as a function of the rms angular momentum of the fissioning system. 2 figures

  5. Tissue Reaction to Different Types of Calcium Hydroxide Paste in Rat.

    Science.gov (United States)

    Zarei, Mina; Javidi, Maryam; Gharechahi, Maryam; Kateb, Moaied; Zare, Reza; Kelagari, Ziba Shirkhani

    2016-01-01

    The purpose of this study was to compare the biocompatibility of two types of calcium hydroxide paste in subcutaneous tissue in rat. Twenty-two Wistar rats were divided into 4 experimental (n=5 each) and one control (n=2) group. A polyethylene tube filled with either Dentsply or Sure-Paste was implanted in each rat in the experimental groups, while an empty polyethylene tube was used in the control group. After 15 or 60 days, the animals were sacrificed and histopathological examination carried out. Tissue reaction was assessed by inflammatory cell infiltration using a 4-point scoring system, ranging from 0 to 3. Data were analyzed with the Kruskal-Wallis, Wilcoxon, and McNemar tests. Both types of paste induced an inflammatory response at each time point, although the intensity varied. A significant reduction in the number of inflammatory cells was observed at 60 days. Dentsply appeared to induce a more marked inflammatory response at both time points, although the difference was not significant. These results suggest that both types of paste are biocompatible with subcutaneous tissue in rat. PMID:27320294

  6. Subcutaneous tissue reaction to castor oil bean and calcium hydroxide in rats

    Directory of Open Access Journals (Sweden)

    Samira Esteves Afonso Camargo

    2010-06-01

    Full Text Available Castor oil bean cement (COB is a new material that has been used as an endodontic sealer, and is a candidate material for direct pulp capping. OBJECTIVE: The purpose of this study was to evaluate the biocompatibility of a new formulation of COB compared to calcium hydroxide cement (CH and a control group without any material, in the subcutaneous tissue of rats. MATERIAL AND METHODS: The materials were prepared, packed into polyethylene tubes, and implanted in the rat dorsal subcutaneous tissue. Animals were sacrificed at the 7th and 50th days after implantation. A quantitative analysis of inflammatory cells was performed and data were subjected to ANOVA and Tukey's tests at 5% significance level. RESULTS: Comparing the mean number of inflammatory cells between the two experimental groups (COB and CH and the control group, statistically significant difference (p=0.0001 was observed at 7 and 50 days. There were no significant differences (p=0.111 between tissue reaction to CH (382 inflammatory cells and COB (330 inflammatory cells after 7 days. After 50 days, significantly more inflammatory cells (p=0.02 were observed in the CH group (404 inflammatory cells than in the COB group (177 inflammatory cells. CONCLUSIONS: These results demonstrate that the COB cement induces less inflammatory response within long periods.

  7. Calcium phosphate composite materials including inorganic powders, BSA or duplex DNA prepared by W/O/W interfacial reaction method

    International Nuclear Information System (INIS)

    We reported before that inorganic reaction occurring at the interface of W/O/W emulsion is advantageous to produce hollow spheres (microcapsules) of inorganic matrices such as silica. This process enables us to include various materials into inorganic matrices directly. Calcium phosphates were also produced from NH4H2PO4 and Ca(OH)2 by this interfacial reaction method. Various biomaterials are directly incorporated into crystalline calcium phosphate matrices, when the biomaterials are added to the inner water phase of the W/O/W emulsion. ZrO2 and Al2O3 powders were effectively encapsulated in calcium phosphates such as hydroxyapatite (HAp). The images of backscattered electron of FE-SEM observations indicated that ZrO2 particles were included in HAp, while they adhered to the surface of HAp in the case of a simple precipitation method. Biomacromolecules such as BSA and duplex DNA were also included in HAp using the inner water phases dissolving them. Fluorescent microscopy observations revealed that biomacromolecules incorporated in HAp localized in some domains of the HAp matrices. Biomacromolecules thus included were scarcely liberated into deionized water, indicating their strong encapsulation in HAp. This general and simple methodology will provide various composite materials of calcium phosphates, which are applicable to regenerative medicine, DDS, GDS and more

  8. Buffer storage of thermal energy using the reaction heat of the system calcium oxide/calcium hydroxide

    Science.gov (United States)

    Lehmann, B.

    1986-12-01

    The reaction heat of the system CaO/Ca(OH)2 was investigated as storage effect for thermal energy. The heat from the chemical system is used as a buffer facility for thermal energy, i.e., sensible heat is stored without thermal losses to the environment. In the forward reaction by adding water to the CaO, sensible heat is released, which can be used for heating houses or water, and for generation of steam for industrial purposes. The necessary heat to be fed to the Ca(OH)2 in order to run the reaction inversely can be supplied by solar collector, high temperature reactors, geothermal energy, or combustion of wastes. Heat at temperatures less than 450 C has to be furnished for the loading phase of the reaction. The discharging reaction delivers temperatures up to 400 C. A gas loop was designed, built, and operated to test this kind of heat storage. The quantities which determine the storage and release of energy were deduced and documented. Pressure drops and storage mass behavior are discussed.

  9. Geochemical reactions and dynamics during titration of a contaminated groundwater with high uranium, aluminum, and calcium

    Science.gov (United States)

    Gu, Baohua; Brooks, Scott C.; Roh, Yul; Jardine, Philip M.

    2003-08-01

    This study investigated possible geochemical reactions during titration of a contaminated groundwater with a low pH but high concentrations of aluminum, calcium, magnesium, manganese, and trace contaminant metals/radionuclides such as uranium, technetium, nickel, and cobalt. Both Na-carbonate and hydroxide were used as titrants, and a geochemical equilibrium reaction path model was employed to predict aqueous species and mineral precipitation during titration. Although the model appeared to be adequate to describe the concentration profiles of some metal cations, solution pH, and mineral precipitates, it failed to describe the concentrations of U during titration and its precipitation. Most U (as uranyl, UO 22+) as well as Tc (as pertechnetate, TcO 4-) were found to be sorbed and coprecipitated with amorphous Al and Fe oxyhydroxides at pH below ˜5.5, but slow desorption or dissolution of U and Tc occurred at higher pH values when Na 2CO 3 was used as the titrant. In general, the precipitation of major cationic species followed the order of Fe(OH) 3 and/or FeCo 0.1(OH) 3.2, Al 4(OH) 10SO 4, MnCO 3, CaCO 3, conversion of Al 4(OH) 10SO 4 to Al(OH) 3,am, Mn(OH) 2, Mg(OH) 2, MgCO 3, and Ca(OH) 2. The formation of mixed or double hydroxide phases of Ni and Co with Al and Fe oxyhydroxides was thought to be responsible for the removal of Ni and Co in solution. Results of this study indicate that, although the hydrolysis and precipitation of a single cation are known, complex reactions such as sorption/desorption, coprecipitation of mixed mineral phases, and their dissolution could occur simultaneously. These processes as well as the kinetic constraints must be considered in the design of the remediation strategies and modeling to better predict the activities of various metal species and solid precipitates during pre- and post-groundwater treatment practices.

  10. Influence of Soil Reaction on Phosphorus, Potassium, Calcium and Magnesium Dynamics in Grapevine (Vitis vinifera L.

    Directory of Open Access Journals (Sweden)

    Lepomir Čoga

    2009-03-01

    Full Text Available Influence of soil reaction on phosphorus, potassium, calcium and magnesium dynamics in grapevine was studied on the variety Sauvignon Blanc in 2007, in the Plešivica wine-growing region. Investigations were conducted on three vitisol subtypes: dystric cambisol (pHKCl 3.73-3.76, pseudogley (pHKCl 4.67-4.69 and rendzina on marl (pHKCl 7.21-7.27. To establish the amount and dynamics of P, K, Ca and Mg in plant material, leaf samples were taken three times during the growing period: at the flowering and veraison stages and at the end of the growing period. At all sampling times, significantly higher leaf contents of P, Ca and Mg were found on alkaline soil compared to acid soils, while differences in K levels were not statistically significant. Differences in P contents may be explained by better solubility and thereby better availability of P from Ca-phosphates compared to Al, Mn and Fe-phosphates in acid soils. In addition, the cation ratio K/(Ca+Mg that has a significant influence on grape quality, was also determined in leaves. Compared to optimal values (0.30–0.40, the least favourable ratio K/ (Ca+Mg was recorded at flowering on acid soils (0.38–0.77 and at harvest on calcareous soil (0.12–0.27. Differences in the content of sugar and total acids in must indicate a positive correlation between leaf contents of P, Ca and Mg and sugar content of must, and a negative correlation between leaf contents of P, Ca and Mg and the total acid content of must.

  11. Luminescence properties of dysprosium doped calcium magnesium silicate phosphor by solid state reaction method

    International Nuclear Information System (INIS)

    Dysprosium doped calcium magnesium silicate (CaMgSi2O6:Dy3+) white light emitting phosphor was synthesized by solid state reaction process. The crystal structure of sintered phosphor was monoclinic structure with space group C2/c. Chemical composition of the sintered CaMgSi2O6:Dy3+ phosphor was confirmed by EDX. The prepared CaMgSi2O6:Dy3+ phosphor was excited from 352 nm and their corresponding emission spectra were recorded at blue (470 nm), yellow (570 nm) and red (675 nm) line due to the 4F9/2 → 6H15/2, 4F9/2 → 6H13/2, 4F9/2 → 6H11/2 transitions of Dy3+ ions. The combination of these three emissions constituted as white light confirmed by the Commission Internationale de L'Eclairage (CIE) chromatic coordinate diagram. The possible mechanism of the white light emitting long lasting CaMgSi2O6:Dy3+ phosphor was also investigated. Investigation on afterglow property show that phosphor held fast and slow decay process. The peak of mechanoluminescence (ML) intensity increases linearly with increasing impact velocity of the moving piston. Thus the present investigation indicates that the local piezoelectricity-induced electron bombardment model is responsible to produce ML in prepared CaMgSi2O6:Dy3+ phosphor. - Highlights: • The crystal structure of CaMgSi2O6:Dy3+ phosphor is consistent with standard monoclinic structure. • CIE coordinates of CaMgSi2O6:Dy3+ phosphor is suitable as white light emitting phosphor. • The local piezoelectricity-induced electron bombardment model is responsible to produce ML in CaMgSi2O6:Dy3+ phosphor

  12. Optimization of reaction conditions for the radiolabeling of DOTA and DOTA-peptide with 44m/44Sc and experimental evidence of the feasibility of an in vivo PET generator

    International Nuclear Information System (INIS)

    Introduction: Among the number of generator systems providing radionuclides with decay parameters promising for imaging and treatment applications, there is the 44Ti (T1/2 = 60 years)/44Sc (T1/2 = 3.97 h) generator. This generator provides a longer-lived daughter for extended PET/CT measurements compared to the chemically similar system 68Ge/68Ga. Scandium also exists as 47Sc, a potential therapeutic radionuclide. It is possible to produce 44Sc in a cyclotron using, for example, the 44Ca (d, n) 44Sc nuclear reaction. In that case, the isomeric state 44mSc (T1/2 = 58.6 h) is co-produced and may be used as an in vivo44mSc/44Sc generator. The aim of this study is to evaluate the feasibility of this in vivo44mSc/44Sc generator and to demonstrate that the daughter radionuclide stays inside the chelator after decay of the parent radionuclide. Indeed, the physico-chemical process occurring after the primary radioactive decay (EC, IT, Auger electron …) has prevented in many cases the use of in-vivo generator, because of the post-effect as described in the literature. Methods: The DOTA macrocyclic ligand forms stable complexes with many cations and has been shown to be the most suitable chelating moiety for scandium. Initially, the radiolabeling of DOTA and a DOTA-peptide (DOTATATE) with Sc was performed and optimized as a function of time, pH, metal-to-ligand ratio and temperature. Next, the physico-chemical processes that could occur after the decay (post-effect) were studied. 44mSc(III)-labeled DOTA-peptide was quantitatively adsorbed on a solid phase matrix through a hydrophobic interaction. Elutions were then performed at regular time intervals using a DTPA solution at various concentrations. Finally, the radiolabelled complex stability was studied in serum. Results: Radiolabeling yields ranged from 90% to 99% for metal-to-ligand ratio ranging from 1:10 to 1:500 for DOTA or DOTATATE respectively. The optimum physico-chemical parameters were pH = 4–6, t = 20 min, T

  13. Luminescence properties of dysprosium doped calcium magnesium silicate phosphor by solid state reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, Ishwar Prasad, E-mail: ishwarprasad1986@gmail.com [School of Studies in Physics & Astrophysics, Pt. Ravishankar Shukla University, Raipur, C.G. 492010 (India); Chandrakar, Priya; Baghel, R.N.; Bisen, D.P.; Brahme, Nameeta [School of Studies in Physics & Astrophysics, Pt. Ravishankar Shukla University, Raipur, C.G. 492010 (India); Tamrakar, Raunak Kumar [Department of Applied Physics, Bhilai Institute of Technology, Durg, C.G. 491001 (India)

    2015-11-15

    Dysprosium doped calcium magnesium silicate (CaMgSi{sub 2}O{sub 6}:Dy{sup 3+}) white light emitting phosphor was synthesized by solid state reaction process. The crystal structure of sintered phosphor was monoclinic structure with space group C2/c. Chemical composition of the sintered CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor was confirmed by EDX. The prepared CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor was excited from 352 nm and their corresponding emission spectra were recorded at blue (470 nm), yellow (570 nm) and red (675 nm) line due to the {sup 4}F{sub 9/2} → {sup 6}H{sub 15/2}, {sup 4}F{sub 9/2} → {sup 6}H{sub 13/2}, {sup 4}F{sub 9/2} → {sup 6}H{sub 11/2} transitions of Dy{sup 3+} ions. The combination of these three emissions constituted as white light confirmed by the Commission Internationale de L'Eclairage (CIE) chromatic coordinate diagram. The possible mechanism of the white light emitting long lasting CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor was also investigated. Investigation on afterglow property show that phosphor held fast and slow decay process. The peak of mechanoluminescence (ML) intensity increases linearly with increasing impact velocity of the moving piston. Thus the present investigation indicates that the local piezoelectricity-induced electron bombardment model is responsible to produce ML in prepared CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor. - Highlights: • The crystal structure of CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor is consistent with standard monoclinic structure. • CIE coordinates of CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor is suitable as white light emitting phosphor. • The local piezoelectricity-induced electron bombardment model is responsible to produce ML in CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor.

  14. Buffering storage of thermal energy by means of the reaction heat of the system calcium oxide/calcium hydroxide. Die Pufferspeicherung thermischer Energie mittels der Waermetoenung des Systems Calciumoxid/Calciumhydroxid

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, B.

    1986-12-01

    The heat of reaction from the chemical system calcium oxide/calcium hydroxide is used as a buffering facility for thermal energy. In case of forward reaction by adding water to calcium oxide, reaction heat is released that can be used for heating, hot water supply, or for generating steam for industrial purposes. For running the reaction reversely, energy has to be fed into calcium hydroxide to gain calcium oxide. This energy could be supplied by concentrating solar collectors or by high-temperature reactors (HTR) using nuclear energy. Other possible heat sources can be volcanic rocks delivering geothermal energy and refuse-fuelled power plants. Heat at temperatures exceeding 450/sup 0/C has to be furnished for the loading phase. The discharging reaction delivers temperatures up to 400/sup 0/C. For testing this kind of heat storage, a gas-loop has been designed, built and operated. The energy transport in the cycle is provided by an inert gas stream (nitrogen) with variable volumes of steam entrained. The operating conditions were measured by transducers and evaluated with computer programs. The documentation of the measured data and of the deduced values, i.e. energy release and storage rates, pressure drops and behaviour of the storage mass, are presented in this report.

  15. A role for calcium hydroxide and dolomite in water: acceleration of the reaction under ultraviolet light.

    Science.gov (United States)

    Nagase, Hiroyasu; Tsujino, Hidekazu; Kurihara, Daisuke; Saito, Hiroshi; Kawase, Masaya

    2014-04-01

    Organic environmental pollutants are now being detected with remarkably high frequency in the aquatic environment. Photodegradation by ultraviolet light is sometimes used as a method for removing organic chemicals from water; however, this method is relatively inefficient because of the low degradation rates involved, and more efficient methods are under development. Here we show that the removal of various organic pollutants can be assisted by calcined dolomite in aqueous solution under irradiation with ultraviolet light. It was possible to achieve substantial removal of bisphenol A, chlorophenols, alkylphenols, 1-naphthol and 17β-estradiol. The major component of dolomite responsible for the removal was calcium hydroxide. Our results demonstrate that the use of calcium hydroxide with ultraviolet light irradiation can be a very effective method of rapidly removing organic environmental pollutants from water. This is a new role for calcium hydroxide and dolomite in water treatment. PMID:24359914

  16. The resonance triplet at E_alpha = 4.5 MeV in the 40Ca(alpha,gamma)44Ti reaction

    CERN Document Server

    Schmidt, Konrad; Anders, Michael; Bemmerer, Daniel; Boretzky, Konstanze; Caciolli, Antonio; Degering, Detlev; Dietz, Mirco; Dressler, Rugard; Elekes, Zoltán; Fülöp, Zsolt; Gyürky, György; Hannaske, Roland; Junghans, Arnd R; Marta, Michele; Menzel, Marie-Luise; Munnik, Frans; Schumann, Dorothea; Schwengner, Ronald; Szücs, Tamás; Wagner, Andreas; Yakorev, Dmitry; Zuber, Kai

    2013-01-01

    The 40Ca(alpha,gamma)44Ti reaction is believed to be the main production channel for the radioactive nuclide 44Ti in core-collapse supernovae. Radiation from decaying 44Ti has been observed so far for two supernova remnants, and a precise knowledge of the 44Ti production rate may help improve supernova models. The 40Ca(alpha,gamma)44Ti astrophysical reaction rate is determined by a number of narrow resonances. Here, the resonance triplet at E_alpha = 4497, 4510, and 4523 keV is studied both by activation, using an underground laboratory for the gamma counting, and by in-beam gamma spectrometry. The target properties are determined by elastic recoil detection analysis and by nuclear reactions. The strengths of the three resonances are determined to omega gamma = (0.92+-0.20), (6.2+-0.5), and (1.32+-0.24) eV, respectively, a factor of two more precise than before. The strengths of this resonance triplet may be used in future works as a point of reference. In addition, the present new data directly affect the as...

  17. Fast preparation of Na0.44MnO2 nanorods via a high NaOH concentration hydrothermal soft chemical reaction and their lithium storage properties

    International Nuclear Information System (INIS)

    This paper describes a high NaOH concentration hydrothermal soft chemical reaction to prepare Na0.44MnO2 nanorods. In this process, Na-birnessite precursors and concentrated NaOH solution are introduced into the hydrothermal reaction. As a result, the hydrothermal time can be significantly shortened from 96 to 24 h, the hydrothermal temperature can be reduced from 205 to 180 °C and the yield of Na0.44MnO2 can be increased from about 0.6 to about 2.4 g/(mL.day), respectively. Furthermore, the obtained Na0.44MnO2 nanorods with one-dimensional tunnel structures exhibit favorable electrochemical lithium storage properties, which make them promising for the cathode materials of lithium-ion batteries

  18. Un-catalyzed tandem Knoevenagel-Michael reaction for the synthesis of 4,4'-(arylmethylene)bis(7H-pyrazol-5-ols) in aqueous medium

    Institute of Scientific and Technical Information of China (English)

    Nilesh P. Tale; Girdharilal B. Tiwari; Nandkishor N. Karade

    2011-01-01

    An environmentally benign un-catalyzed one-pot synthesis of 4,4'-(arylmethylene)bis(7H-pyrazol-5-ols) has been reported via tandem Knoevenagel-Michael reaction of aldehydes with two equivalents of 3-methyl-l-phenyl-lH-pyrazol-5(4H)-one in aqueous medium.

  19. Acute intraoperative reactions during the injection of calcium sulfate bone cement for the treatment of unicameral bone cysts: a review of four cases.

    Science.gov (United States)

    Nystrom, Lukas; Raw, Robert; Buckwalter, Joseph; Morcuende, Jose A

    2008-01-01

    Unicameral bone cysts can predispose patients to pathologic fracture and deformities of growth. Treatment options vary from continuous decompression with transcortical placement of a cannulated screw to percutaneous aspiration and injection of medical-grade calcium sulfate. From 2005 to 2007, we treated 22 patients with unicameral bone cysts using aspiration and injection of calcium sulfate. Three patients experienced acute laryngospasm and one patient developed tachyarrhythmia, temporarily, associated with injection of calcium sulfate. All reactions occurred in patients under age 18 without predisposing risk factors and resolved spontaneously with supportive care. Although the mechanism is unclear, we hypothesize that these reactions are either due to the nociceptive stimulus of the calcium sulfate injection or a systemic calcium bolus. Clinicians using this product for this indication should be aware that such reactions may occur. We suggest endotracheal intubation and communication to the anesthesiologist about the time of the injection in preparation for these idiopathic responses. Further research is necessary to determine exactly how this reaction occurs and how it can be avoided. PMID:19223954

  20. Reaction mechanism and influence factors analysis for calcium sulfide generation in the process of phosphogypsum decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Liping, E-mail: lpma2522@hotmail.com [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Niu, Xuekui; Hou, Juan; Zheng, Shaocong; Xu, Wenjuan [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

    2011-11-10

    Highlights: Black-Right-Pointing-Pointer Reusing phosphogypsum is to decompose and recycle Ca and sulfur. Black-Right-Pointing-Pointer FactSage6.1 software was used to simulate the decomposition reactions. Black-Right-Pointing-Pointer Experiments had been taken with high sulfur concentration coal as reducing agent. Black-Right-Pointing-Pointer The reaction mechanism of CaS generation had been analysis, 1100 Degree-Sign C could be the best temperature for PG decomposition. - Abstract: FactSage6.1 software simulation and experiments had been used to analysis the reaction mechanism and influence factors for CaS generation during the process of phosphogypsum decomposition. Thermodynamic calculation showed that the reaction for CaS generation was very complex and CaS was generated mainly through solid-solid reaction and gas-solid reaction. The proper CO and CO{sub 2} have benefit for improving the decomposition effects of phosphogypsum and reducing the generation of CaS at 1100 Degree-Sign C. Using high sulfur concentration coal as reducer, the proper reaction conditions to control the generation of CaS were: the coal particle size was between 60 mesh and 100 mesh, reaction temperature was above 1100 Degree-Sign C and the heating rate was 5 Degree-Sign C/min. Experimental and theoretical calculation indicated that the concentration of CaS was only ten percents in the solid product at 1100 Degree-Sign C, which is favorable for the further cement producing using solid production.

  1. Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Webler, Geovana D. [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Correia, Ana C.C.; Barreto, Emiliano [Laboratório de Biologia Celular, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Fonseca, Eduardo J.S., E-mail: eduardo@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil)

    2015-07-15

    Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity.

  2. Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

    International Nuclear Information System (INIS)

    Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity

  3. Characterizing Pyroxene Reaction Space in Calcium-Aluminum Rich Inclusions: Oxidation During CAI Rim Formation

    Science.gov (United States)

    Dyl, K. A.; Young, E. D.

    2009-12-01

    We define the reaction space that controls changes in pyroxene composition in CAIs and Wark-Lovering (WL) rims in an oxidizing solar nebula. Ti-rich pyroxenes in CAIs record a sub-solar oxygen fugacity (Ti3+/Ti4+~1.5). WL rim pyroxenes in the CAI Leoville 144A have a distinctly lower oxidation state.This difference supports WL rim condensation in an environment of increasing O2(g) and Mg(g) (Simon et al. 2005). We used the following phase components to identify four linearly independent reactions (Thompson 1982): diopside, CaTs (Al2Mg-1Si-1), T3 (Ti3+AlMg-1Si-1), T4 (Ti4+Al2Mg-1Si-2), En (MgCa-1), perovskite, O(g), Mg(g), SiO(g), and Ca(g). Compositional variation in this system is dominated by two reactions. The first is oxidation of Ti3+ via reaction with O and Mg in the gas phase: 1.5 O(g) + Mg(g) → ¼ Di + [Ti4+Mg3/4Ti3+-1Ca-1/4Si-1/2] (1). Pyroxene is produced and En is introduced. The second reaction (2) is perovskite formation. It is observed in the WL rim of Leoville 144A, and experiments confirm that an elevated Ti component converts pyroxene to perovskite(Gupta et al. 1973). MgCa-1 is the third linearly independent reaction (3). They combine to give: ½ Di + x Ca(g)→ x Mg(g)+ Pv + [Mg1/2-xSiTi4+-1Ca-1/2+x](2,3). Unlike (1), pyroxene is consumed in this reaction. The parameter x defines the extent of Mg-Ca exchange. When x > 0.5, WL rim formation occurs in an environment where Mg is volatile and Ca condenses. The reaction space defined by reactions (1) and (2,3) describes the transition from CAI interior to WL rims. WL rim pyroxene Ti contents, [CaTs], and Ca < 1 pfu are all explained in this space. The fourth linearly independent reaction is SiO(g):1/8 Di + ¼ Mg(g)→ ¾ SiO(g) + [Mg3/8Ca1/8Ti4+Ti3+-1Si-1/2](4). Silica reduction forms Ti4+, releasing SiO(g). (4) does not describe the oxidation of Ti3+ in WL rim pyroxene, but (1) - (4) results in En formation directly from the gas phase. This may explain WL rim analyses that have Si contents in excess

  4. 45V(p,γ) thermonuclear reaction rate relevant to 44Ti production in core-collapse supernovae: General estimates and shell model analysis

    International Nuclear Information System (INIS)

    The lack of knowledge of the 45V(p,γ) reaction rate has been shown to contribute a large uncertainty to the production of 44Ti in core-collapse supernovae. By considering likely contributions from resonances associated with 46Cr states that are the isobaric analog of states in 46Ti, we have determined that the currently accepted value of the 45V(p,γ) reaction rate is unlikely to be inaccurate by more than an order of magnitude. These conclusions are confirmed by the shell model calculations with the FPD6 effective interaction

  5. Atomic force microscopy of photochemistry and the Baeyer-Villiger reaction of 4,4{sup '}-dimethylbenzophenone in the solid state

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Q.D.; Wang, C.; Xu, S.D.; Bai, C.L. [Inst. of Chemistry, Chinese Academy of Sciences, Beijing (China); Li, Y.; Yan, X.J. [Inst. of Chemical Metallurgy, Chinese Academy of Sciences, Beijing (China)

    2001-08-01

    Nanostructures are formed by photodimerization of crystalline 4,4{sup '}-dimethylbenzophenone (1) through intermolecular hydrogen abstraction and Baeyer-Villiger reaction of 1 with m-chloroperoxybenzoic acid (MCPBA) (5) in the solid state. Atomic force microscopy (AFM) reveals that the crystal face (001) of 1 during photodimerization exhibits volcanoes, whereas the same face (001) of 1 yields both craters and volcanoes all over the surface from the contact edge of the crystals during the Baeyer-Villiger reaction. All the experimental results are correlated with the bulk crystal structure. Molecular interpretation of the AFM features of 1 is given. (orig.)

  6. Platelet-activating factor in Iberian pig spermatozoa: receptor expression and role as enhancer of the calcium-induced acrosome reaction.

    Science.gov (United States)

    Bragado, M J; Gil, M C; Garcia-Marin, L J

    2011-12-01

    Platelet-activating factor (PAF) is a phospholipid involved in reproductive physiology. PAF receptor is expressed in some mammalian spermatozoa species where it plays a role in these germ-cell-specific processes. The aim of this study is to identify PAF receptor in Iberian pig spermatozoa and to evaluate PAF's effects on motility, viability and acrosome reaction. Semen samples from Iberian boars were used. PAF receptor identification was performed by Western blotting. Spermatozoa motility was analysed by computer-assisted sperm analysis system, whereas spermatozoa viability and acrosome reaction were evaluated by flow cytometry. Different PAF concentrations added to non-capacitating medium during 60 min have no effect on any spermatozoa motility parameter measured. Acrosome reaction was rapid and potently induced by 1 μm calcium ionophore A23187 showing an effect at 60 min and maximum at 240 min. PAF added to a capacitating medium is not able to induce spermatozoa acrosome reaction at any time studied. However, PAF, in the presence of A23187, significantly accelerates and enhances the calcium-induced acrosome reaction in a concentration-dependent manner in Iberian boar spermatozoa. Exogenous PAF does not affect at all spermatozoa viability, whereas slightly exacerbated the A23187-induced loss in viability. This work demonstrates that PAF receptor is expressed in Iberian pig spermatozoa and that its stimulation by PAF regulates the calcium-induced acrosome reaction. This work contributes to further elucidate the physiological regulation of the most relevant spermatozoa functions for successful fertilization: acrosome reaction. PMID:22023717

  7. Reaction Mechanism of Calcium Hydroxide with Gaseous Hydrogen Chloride Mécanisme de réaction de l'hydroxyde de calcium avec de l'acide chlorhydrique gazeux

    Directory of Open Access Journals (Sweden)

    Allal K. M.

    2006-12-01

    Full Text Available The reduction of acid gas content in combustion or incineration flue gases can be carried out by reaction with dry, fine alkaline sorbents such as calcium oxide or calcium hydroxide. In the present work, in addition to the thermodynamic study of the different reactions involved in the dechlorination process, an experimental study to identify the reaction products by means of X-ray diffraction, electron microscopy and thermogravimetry has been carried out. It has been shown that the reaction of hydrochloric acid with hydrated lime leads to the formation of not only calcium chloride but calcium hydroxichloride. La diminution de la teneur en gaz acides dans les effluents provenant des unités de combustion ou d'incinération peut être accomplie en faisant réagir ces gaz polluants avec des absorbants alcalins tels que l'oxyde ou l'hydroxyde de calcium. Dans cet article, à l'étude thermodynamique des différentes réactions mises en jeu durant le processus de déchloruration, s'ajoute une étude expérimentale menant à l'identification des produits finaux en utilisant la diffraction X, la microscopie électronique ainsi que la thermogravimétrie. A l'issue de cette étude, il a été montré que la réaction de Ca(OH2 avec HCl entraîne la formation non seulement de CaCI2 mais aussi CaCIOH.

  8. Development of a method based on inductively coupled plasma-dynamic reaction cell-mass spectrometry for the simultaneous determination of phosphorus, calcium and strontium in bone and dental tissue

    Energy Technology Data Exchange (ETDEWEB)

    De Muynck, David [Ghent University, Department of Analytical Chemistry, Krijgslaan 281-S12, BE-9000 Ghent (Belgium)], E-mail: David.DeMuynck@UGent.be; Vanhaecke, Frank [Ghent University, Department of Analytical Chemistry, Krijgslaan 281-S12, BE-9000 Ghent (Belgium)], E-mail: Frank.Vanhaecke@UGent.be

    2009-05-15

    A method, based on the use of a quadrupole-based inductively coupled plasma-mass spectrometry instrument equipped with a quadrupole-based collision/reaction cell (dynamic reaction cell, DRC), was developed for the simultaneous determination of phosphorus, calcium and strontium in bone and dental (enamel and dentine) tissue. The use of NH{sub 3}, introduced at a gas flow rate of 0.8 mL min{sup -1} in the dynamic reaction cell, combined with a rejection parameter q (RPq) setting of 0.65, allows interference-free determination of calcium via its low-abundant isotopes {sup 42}Ca, {sup 43}Ca and {sup 44}Ca, and of strontium via its isotopes {sup 86}Sr and {sup 88}Sr that are freed from overlap due to the occurrence of ArCa{sup +} and/or Ca{sub 2}{sup +} ions. Also the determination of phosphorus ({sup 31}P, mono-isotopic) was shown to be achievable using the same dynamic reaction cell operating conditions. The bone certified reference materials NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal were used for validation of the measurement protocol that was shown capable of providing accurate and reproducible results. Detection limits of P, Ca and Sr in dental tissue digests were established as 3 {mu}g L{sup -1} for P, 2 {mu}g L{sup -1} for Ca and 0.2 {mu}g L{sup -1} for Sr. This method can be used to simultaneously (i) evaluate the impact of diagenesis on the elemental and isotopic composition of buried skeletal tissue via its Ca/P ratio and (ii) determine its Sr concentration. The measurement protocol was demonstrated as fit-for-purpose by the analysis of a set of teeth of archaeological interest for their Ca/P ratio and Sr concentration.

  9. Development of a method based on inductively coupled plasma-dynamic reaction cell-mass spectrometry for the simultaneous determination of phosphorus, calcium and strontium in bone and dental tissue

    Science.gov (United States)

    De Muynck, David; Vanhaecke, Frank

    2009-05-01

    A method, based on the use of a quadrupole-based inductively coupled plasma-mass spectrometry instrument equipped with a quadrupole-based collision/reaction cell (dynamic reaction cell, DRC), was developed for the simultaneous determination of phosphorus, calcium and strontium in bone and dental (enamel and dentine) tissue. The use of NH 3, introduced at a gas flow rate of 0.8 mL min - 1 in the dynamic reaction cell, combined with a rejection parameter q (RPq) setting of 0.65, allows interference-free determination of calcium via its low-abundant isotopes 42Ca, 43Ca and 44Ca, and of strontium via its isotopes 86Sr and 88Sr that are freed from overlap due to the occurrence of ArCa + and/or Ca 2+ ions. Also the determination of phosphorus ( 31P, mono-isotopic) was shown to be achievable using the same dynamic reaction cell operating conditions. The bone certified reference materials NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal were used for validation of the measurement protocol that was shown capable of providing accurate and reproducible results. Detection limits of P, Ca and Sr in dental tissue digests were established as 3 µg L - 1 for P, 2 µg L - 1 for Ca and 0.2 µg L - 1 for Sr. This method can be used to simultaneously (i) evaluate the impact of diagenesis on the elemental and isotopic composition of buried skeletal tissue via its Ca/P ratio and (ii) determine its Sr concentration. The measurement protocol was demonstrated as fit-for-purpose by the analysis of a set of teeth of archaeological interest for their Ca/P ratio and Sr concentration.

  10. Development of a method based on inductively coupled plasma-dynamic reaction cell-mass spectrometry for the simultaneous determination of phosphorus, calcium and strontium in bone and dental tissue

    International Nuclear Information System (INIS)

    A method, based on the use of a quadrupole-based inductively coupled plasma-mass spectrometry instrument equipped with a quadrupole-based collision/reaction cell (dynamic reaction cell, DRC), was developed for the simultaneous determination of phosphorus, calcium and strontium in bone and dental (enamel and dentine) tissue. The use of NH3, introduced at a gas flow rate of 0.8 mL min-1 in the dynamic reaction cell, combined with a rejection parameter q (RPq) setting of 0.65, allows interference-free determination of calcium via its low-abundant isotopes 42Ca, 43Ca and 44Ca, and of strontium via its isotopes 86Sr and 88Sr that are freed from overlap due to the occurrence of ArCa+ and/or Ca2+ ions. Also the determination of phosphorus (31P, mono-isotopic) was shown to be achievable using the same dynamic reaction cell operating conditions. The bone certified reference materials NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal were used for validation of the measurement protocol that was shown capable of providing accurate and reproducible results. Detection limits of P, Ca and Sr in dental tissue digests were established as 3 μg L-1 for P, 2 μg L-1 for Ca and 0.2 μg L-1 for Sr. This method can be used to simultaneously (i) evaluate the impact of diagenesis on the elemental and isotopic composition of buried skeletal tissue via its Ca/P ratio and (ii) determine its Sr concentration. The measurement protocol was demonstrated as fit-for-purpose by the analysis of a set of teeth of archaeological interest for their Ca/P ratio and Sr concentration.

  11. The Feasibility of direct measurement of the {sup 44}Ti(α, p){sup 47}V and {sup 40}Ca(α, p){sup 43}Sc reactions in forward kinematics at astrophysically relevant temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Al-Abdullah, T. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Dresden (Germany); The Hashemite University, Physics Department, P.O. Box 150459, Zarqa (Jordan); Akhmadaliev, S.; Bemmerer, D.; Sobiella, M. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Dresden (Germany); Ayranov, M. [Directorate-General for Energy, European Commission, Luxembourg (Luxembourg); Dressler, R.; Schumann, D.; Stowasser, T. [Paul Scherrer Institute, Laboratory of Radiochemistry and Environmental Chemistry, Villigen PSI (Switzerland); Elekes, Z. [Institute for Nuclear Research of the Hungarian Academy of Sciences (MTA ATOMKI), Debrecen (Hungary); Kivel, N. [Paul Scherrer Institute, Nuclear Energy and Safety, Hot Laboratory Division, Villigen PSI (Switzerland); Schmidt, K.; Takacs, M.P. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Dresden (Germany); Technische Universitaet Dresden, Institute of Nuclear and Particle Physics, Dresden (Germany); Zuber, K. [Technische Universitaet Dresden, Institute of Nuclear and Particle Physics, Dresden (Germany)

    2014-09-15

    Understanding the synthesis of radioactive {sup 44}Ti in the α-rich freeze-out following core-collapse supernovae may help to better interpret such explosive events. The γ-ray lines from the decay of {sup 44}Ti have been observed by space-based γ-ray telescopes from two supernova remnants. It is believed that the {sup 44}Ti(α, p){sup 47}V reaction dominates the destruction of {sup 44}Ti, while the {sup 40}Ca(α, p){sup 43}Sc reaction removes fuel from the main {sup 44}Ti production reaction {sup 40}Ca(α, γ){sup 44}Ti. Here we report on a possible technique to determine both reaction rates at astrophysically relevant energies in forward kinematics. The first reaction will be performed using a 1-10 MBq {sup 44}Ti target. Two important concerns are considered to make this study possible: The amount of stable Ti in the radioactive target, which will be prepared via spallation reactions at Paul Scherrer Institute (PSI), and the degree of radioactive contaminations in the experimental setup due to sputtered {sup 44}Ti atoms after intensive irradiations. Several online and offline measurements in parallel with Monte Carlo simulations were performed to investigate these issues. (orig.)

  12. The Feasibility of direct measurement of the 44Ti(α, p)47V and 40Ca(α, p)43Sc reactions in forward kinematics at astrophysically relevant temperatures

    International Nuclear Information System (INIS)

    Understanding the synthesis of radioactive 44Ti in the α-rich freeze-out following core-collapse supernovae may help to better interpret such explosive events. The γ-ray lines from the decay of 44Ti have been observed by space-based γ-ray telescopes from two supernova remnants. It is believed that the 44Ti(α, p)47V reaction dominates the destruction of 44Ti, while the 40Ca(α, p)43Sc reaction removes fuel from the main 44Ti production reaction 40Ca(α, γ)44Ti. Here we report on a possible technique to determine both reaction rates at astrophysically relevant energies in forward kinematics. The first reaction will be performed using a 1-10 MBq 44Ti target. Two important concerns are considered to make this study possible: The amount of stable Ti in the radioactive target, which will be prepared via spallation reactions at Paul Scherrer Institute (PSI), and the degree of radioactive contaminations in the experimental setup due to sputtered 44Ti atoms after intensive irradiations. Several online and offline measurements in parallel with Monte Carlo simulations were performed to investigate these issues. (orig.)

  13. 44例聚明胶肽注射液不良反应的文献分析%Literature Analysis of 44 Cases of Adverse Drug Reactions Induced by Polygeline Injection

    Institute of Scientific and Technical Information of China (English)

    陈海涛; 张临宏; 昝旺

    2015-01-01

    Objective Through analyzing adverse drug reaction cases of polygeline injection to explore the regularity and cause of adverse drug reactions, provide reference for clinical rational drug use. Methods By retrieving CNKI database and Wanfang database, 44 cases of polygeline injection ADRs reported from 26 literatures were analyzed. Results Most of the ADRs are immediate response type, 91% cases happened within 30 mins, which involv multiple systems and organs including systemic lesions(62.50%) and cardiovascular lesions(10.94%). Allergic shock and severe anaphylactoid reactions are more obvious. At the same time, new ADRs are found in 44 cases. Conclusion More at tention should be paid to the ADRs of polygeline injection and the monitoring of medication should also be strengthened to ensure the safe medication.%目的:通过对聚明胶肽注射液致不良反应文献的病例进行分析,探讨其引起不良反应的规律和原因,为临床合理用药提供参考。方法检索中国期刊全文数据库和万方数据库所载的聚明胶肽不良反应文献,对26篇目标文献所报道的44例病例报告进行统计分析。结果聚明胶肽注射液所致不良反应多数为速发型,91%的个案发生在30 min内;聚明胶肽致不良反应累及多个系统-器官,其中以全身性损害(62.50%)和心血管系统损害(10.94%)为主,过敏性休克和严重过敏样反应突出,同时也有新的不良反应出现。结论临床应重视聚明胶肽注射液的不良反应,加强用药监测,确保用药安全。

  14. Neutron induced reactions on aluminum-26, chloride-36 and calcium-41 and their astrophysical implications

    Science.gov (United States)

    de Smet, Liesbeth Paula

    In this work (n,p) and (n,a) reactions on 26 A1, 36 Cl and 41 Ca are studied as a function of the neutron energy. The measurements were performed at the high resolution GELINA time-of-flight facility of the IRMM in Geel, Belgium. Besides the nuclear physics information obtained from the resonance analysis of the reaction cross sections, these reactions are of importance in the understanding of the observed 36 S and 26 Al solar abundances. In the case of 26 Al, the 26 A1(n,a) 23 Na cross section up to 45 keV has been determined. Six resonances are observed. For three of them, the total level width and the spin could be calculated. For most of the resonances the obtained resonance parameters are in agreement with previous data. The calculated Maxwellian Averaged Cross Section values (MACS) used in stellar model calculations confirm that 26 Al is indeed severely depleted by neutron captures in AGB stars. In the (n,p) and (n,a) measurements on 36 Cl, eighteen resonances are observed in the energy region up to 250 keV, whereas eight were identified before. Only the lowest energy resonance shows a significant (n,(x)-contribution of (76±7)%, which is in perfect agreement with the value reported before. Furthermore, for four resonances, the resonance strength, spin, total and partial width G p could be determined. They are in good agreement with previous data, but the achieved accuracy is better. The calculated MACS values are used in stellar model calculations to trace the origin of 36 S and reveal that the weak component of the s-process occurring in massive stars accounts for almost the entire production of solar 36 S. The 41 Ca(n,a) 3 8Ar measurement is the first ever reported in the resonance region and affects the 36 S abundance through 41 Ca(n,a) 38 Ar(n,g) 39 Ar(n,a) 36 S. Twelve resonances are observed in the energy region up to 45 keV. For most of them the area, the total width, the spin and a value for G n /G p could be determined. After extension of the energy

  15. Effect of heparin, caffeine and calcium ionophore A23187 on in vitro induction of the acrosome reaction of fresh ram spermatozoa

    OpenAIRE

    K.H. El-Shahat; M.I. Taysser; M.R. Badr; K.A. Zaki

    2016-01-01

    Objective: To determine the effect of different concentrations of heparin, caffeine or calcium ionophore and incubation time on motility, hyperactivity (HA) and acrosome reaction (AR) of ram sperm in vitro. Methods: Semen samples were collected by artificial vagina from three mature ram. Split fractions (0.1 mL) of the pooled semen were layered under 1 mL of S-TALP medium supplemented with either heparin (10, 25, 50, 75 and 100 μg/mL), caffeine (0.5, 0.75, 1, 2 mg/mL), or calcium ionophore...

  16. Synthesis of symmetrical 2,2',4,4'-tetrasubstituted [4,4'-bithiazole]-5,5'(4H,4'H)-diones and their reactions with some nucleophiles

    DEFF Research Database (Denmark)

    Andersen, Kenneth K.; Bray, Diana D.; Kjær, Anders;

    1997-01-01

    ,4'-dibenzyl-[4,4'-bithiazole]-5,5'(4H,4'H)-dione were treated with nocleophiles. The former gave imide derivatives of alfa,alfa-dehydrodimeric amino acids when the nucleophile was L-alanine ethyl ester or 1-butylamine. The structure of one of the reaction products, (4R*,5R*)-2,5-diphenyl-2-thiazoline-4......-carboxylic acid and piperidylamide, was established by X-ray crystallography. Treatment of stereoisomeric mixtures of 2,2'-diethoxy-4,4'-bithiazolones with HCl in benzene gave the corresponding racemic and meso bis-(N-carboxythioanhydride)s. A stereoisomeric mixture of the bis(N-carboxythioanhydride)s of...... leucine treated with glycine ethyl ester gave a bicyclic derivative of the alfa,alfa-dehydrodimeric amino acid....

  17. Modified calcium oxide as stable solid base catalyst for Aldol condensation reaction

    Indian Academy of Sciences (India)

    Ying Tang; Jingfang Xu; Xuefan Gu

    2013-03-01

    A highly efficient and stable solid-base catalyst for Aldol condensation was prepared by modifying commercial CaO with benzyl bromide in a simple way. It was found that modified CaO can effectively catalyse the Aldol condensation of cyclohexanone and benzaldehyde, as well as various benzaldehydes, to produce 2-benzylidenecyclohexanone with a good selectivity and high yield. Higher yield of 95.8% was obtained over modified CaO after 3 h, which is short compared with the yield of 92.1% after 12 h over commercial CaO. The influence of several reaction parameters, such as temperature, catalyst loading, was investigated. The humidity test over modified CaO reveals that the basic centres of modified CaO are stable for CO2 and moisture. From the results of Fourier transform-infrared (FT-IR) and Thermogravity analysis (TG) characterization, the modifier was bonded on surface of CaO chemically and almost no Ca(OH)2 formed during the modification process. The type of aldehyde has great influence on the yield of aldol condensation.

  18. Heavy atom effects in the Paternò–Büchi reaction of pyrimidine derivatives with 4,4’-disubstituted benzophenones

    OpenAIRE

    Qin-Hua Song; Jian-Bo Wang; Feng-Feng Kong

    2011-01-01

    The regioselectivity and the photochemical efficiency were investigated in the Paternò–Büchi reaction of 1,3-dimethylthymine (DMT) and 1,3-dimethyluracil (DMU) with benzophenone (1b) and some 4,4’-disubstituted derivatives (dimethoxy (1a), difluoro (1c), dichloro (1d), dibromo (1e) and dicyano benzophenone (1f)) that gives rise to two regioisomeric oxetanes, 2 and 3. The regioselectivity (the ratio of 2/3) decreased gradually for both DMT/DMU photochemical systems from 1...

  19. A study of dissipative processes in the reactions Ar+Au, Ar+Th between 27 and 44 MeV/u measuring the neutron multiplicities

    International Nuclear Information System (INIS)

    A 4 π detector measuring the neutron multiplicities has been used to characterize the degree of violence of the collision. For peripheral collisions, it allows to study the evolution from a massive transfer process towards a participant-spectator type of reaction. Central collisions have been also investigated. From the measurement of the multiplicities of light evaporated particles (n,p,α), the total excitation energy of the composite system has been estimated at 3 incident energies (27, 35, 44 MeV/u). The results indicate clearly the existence of a limiting excitation energy deposition close to 630 MeV, corresponding to a temperature of 5 MeV

  20. A study of dissipative processes in the reactions Ar + Au, Ar + Th between 27 and 44 MeV/u measuring the neutron multiplicities

    International Nuclear Information System (INIS)

    A 4π detector measuring the neutron multiplicities has been used to characterize the degree of violence of the collision. For peripheral collisions, it allows to study the evolution from a massive transfer process towards a participant-spectator type of reaction. Central collisions have been also investigated. From the measurement of the multiplicities of light evaporated particles (n,p,α), the total excitation energy of the composite system has been estimated at 3 incident energies (27, 35, 44 MeV/u). The results indicate clearly the existence of a limiting excitation energy deposition close to 630 MeV, corresponding to a temperature of 5 MeV

  1. Investigation of the particle stability of the isotopes 26O and 32Ne in the reaction 44 MeV/nucleon 48Ca + Ta

    International Nuclear Information System (INIS)

    An attempt has been made to synthesize the extremely neutron-rich isotope 26O in the nuclear reaction 44 MeV/nucleon 48Ca + Ta. Use was made of magnetic separation and identification methods including time-of-flight and ΔE, E measurements. The 26O nucleus appears to be unstable against particle emission since no events attributable to the 26O nucleus were observed at a level one order of magnitude lower than that predicted from the extrapolated yields. The previously unobserved isotope 32Ne was found to be particle-stable and the isotope 31Ne particle-unstable. Neutron-separation energies calculated with different models are tabulated

  2. Heavy atom effects in the Paternò–Büchi reaction of pyrimidine derivatives with 4,4’-disubstituted benzophenones

    Directory of Open Access Journals (Sweden)

    Qin-Hua Song

    2011-01-01

    Full Text Available The regioselectivity and the photochemical efficiency were investigated in the Paternò–Büchi reaction of 1,3-dimethylthymine (DMT and 1,3-dimethyluracil (DMU with benzophenone (1b and some 4,4’-disubstituted derivatives (dimethoxy (1a, difluoro (1c, dichloro (1d, dibromo (1e and dicyano benzophenone (1f that gives rise to two regioisomeric oxetanes, 2 and 3. The regioselectivity (the ratio of 2/3 decreased gradually for both DMT/DMU photochemical systems from 1a to 1f. That is, a halogen atom as an electron-withdrawing group (EWG has a pronounced effect on the regioselectivity. However, the photochemical efficiency of the 1e systems did not show the expected increase, but decreased relative to systems with 1b. Temperature effects on the regioselectivity of 1b–e systems showed some interesting features for systems with heavy atoms (including the 1d and 1e systems, such as higher inversion temperatures, and an entropy-controlled regioselectively whereas the regioselectivity for two other systems (1b and 1c is enthalpy–entropy controlled. A heavy atom effect is suggested to be responsible for these unusual phenomena based on the triplet-diradical mechanism of the Paternò–Büchi reaction.

  3. Kinetic study of the effects of calcium ions on cationic artichoke (Cynara scolymus L.) peroxidase: calcium binding, steady-state kinetics and reactions with hydrogen peroxide.

    Science.gov (United States)

    Hiner, Alexander N P; Sidrach, Lara; Chazarra, Soledad; Varón, Ramón; Tudela, José; García-Cánovas, Francisco; Rodríguez-López, José Neptuno

    2004-01-01

    The apparent catalytic constant (k(cat)) of artichoke (Cynara scolymus L.) peroxidase (AKPC) with 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) increased 130-fold in the presence of calcium ions (Ca2+) but the affinity (K(m)) of the enzyme for ABTS was 500 times lower than for Ca2+-free AKPC. AKPC is known to exhibit an equilibrium between 6-aquo hexa-coordinate and penta-coordinate forms of the haem iron that is modulated by Ca2+ and affects compound I formation. Measurements of the Ca2+ dissociation constant (K(D)) were complicated by the water-association/dissociation equilibrium yielding a global value more than 1000 times too high. The value for the Ca2+ binding step alone has now been determined to be K(D) approximately 10 nM. AKPC-Ca2+ was more resistant to inactivation by hydrogen peroxide (H(2)O(2)) and exhibited increased catalase activity. An analysis of the complex H(2)O(2) concentration dependent kinetics of Ca2+-free AKPC is presented. PMID:15556277

  4. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk;

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...... calcium binds silicon primarily as calcium silicates and less as potassium calcium silicates....

  5. Variations of protein profiles and calcium and phospholipase A2 concentrations in thawed bovine semen and their relation to acrosome reaction

    Directory of Open Access Journals (Sweden)

    V. Alonso Marques

    2000-12-01

    Full Text Available Just as calcium plays an integral role in acrosome capacitation and reaction, several spermatozoon proteins have been reported as binding to the ovum at fertilization. We examined the relationship between thawed bovine semen protein profiles, seminal plasma calcium ion concentration, spermatozoon phospholipase A2 (PLA2 activity and acrosome reaction. Electrophoretic profile analysis of spermatozoa and bovine seminal plasma proteins (total and membrane revealed qualitative and quantitative differences among bulls. Variations in PLA2 and seminal plasma calcium concentration indicated genetic diversity among individuals. A 15.7-kDa membrane protein was significantly correlated (r = 0.71 with acrosome reaction, which in turn has been associated with in vivo fertility.Várias proteínas que constituem o espermatozóide têm sido relatadas como sendo proteínas que se ligam ao óvulo no momento da fertilização, bem como íons cálcio têm um papel importante na capacitação e reação acrossômica. Baseado nisto, este estudo teve como objetivo analisar e correlacionar proteínas do sêmen congelado bovino de diferentes raças, concentração de íons cálcio no plasma seminal e atividade da fosfolipase A2 do espermatozóide com a reação acrossômica, visando encontrar fatores que influenciem no processo de fertilização bovina. Análises do perfil eletroforético das proteínas (totais e de membrana do espermatozóide e do plasma seminal bovino revelaram variabilidade protéica entre indivíduos na qual diferenças qualitativas e quantitativas foram identificadas. A quantificação da fosfolipase A2, bem como da concentração de cálcio no plasma seminal revelaram diversidade genética entre touros. Uma proteína de 15,7 kDa apresentou correlação significativa (0.71 com a reação acrossômica, que pode estar diretamente relacionada com a fertilização in vivo e deste modo outros experimentos podem ser realizados a fim de investigar a

  6. Impregnating Coal With Calcium Carbonate

    Science.gov (United States)

    Sharma, Pramod K.; Voecks, Gerald E.; Gavalas, George R.

    1991-01-01

    Relatively inexpensive process proposed for impregnating coal with calcium carbonate to increase rates of gasification and combustion of coal and to reduce emission of sulfur by trapping sulfur in calcium sulfide. Process involves aqueous-phase reactions between carbon dioxide (contained within pore network of coal) and calcium acetate. Coal impregnated with CO2 by exposing it to CO2 at high pressure.

  7. Non-equilibrium thermo-chemical heat storage in porous media: Part 2 – A 1D computational model for a calcium hydroxide reaction system

    International Nuclear Information System (INIS)

    Thermal energy storage technologies can facilitate the transition to an energy system based largely on renewable sources and enable efficiency gains for industrial processes in general. Due to their specific advantages, various concepts of thermo-chemical storage systems are being developed. They share characteristic features of mass and heat transport that are strongly coupled through a variety of physical and chemical phenomena. To facilitate the understanding of the coupled multi-physics processes inside such systems, a versatile conceptual model for directly permeated reactive beds was developed in part 1 of this work. It was based on thermodynamic principles and the Theory of Porous Media. The model was then implemented into OpenGeoSys, a scientific finite element simulation software. In this article, the model is specified to the well-studied calcium hydroxide reaction system to illustrate its practical applicability. Sensitivity analyses reveal the influence of particle diameter, porosity, permeability, mass flux, and reaction rate. Two distinct “reaction waves” are identified to migrate through the reactor. The power required to pump the gas stream was decomposed into parts related to the classical mechanical pressure drop and to the chemical reaction. The results can be used for the optimization of thermochemical heat storage systems. - Highlights: • Detailed investigation of coupled multiphysics in thermochemical heat storage. • Thermodynamically consistent model for thermochemical heat storage systems. • Analysis of thermal power depending on material and process parameters. • Two reaction waves are identified that traverse the reactor. • Mechanical pumping power splits into mechanically and chemically induced parts

  8. Electrochemical determination of the Gibb's energies of metal ion chelation, solid--solid phase transitions, and calcium isotope exchange reactions

    International Nuclear Information System (INIS)

    The experimental determinations of the equilibrium constants for the following reactions, (1) 40CaCO3(s) + 48CaCl2(aq) = 48CaCO3(s) + 40CaCl2(aq), (2) CaCO3(arag. or vat.) = CaCo3(calcite), (3) Ba2+(aq) + Y(s) = BaY2+(aq) where Y refers to dicyclohexyl-18-crown-6 cyclic polyether and arag. and vat. refer to aragonite and vaterite, have been carried out in electrochemical double cells without liquid junctions. The double cell diagrams are illustrated. The standard potentials of reactions (1), (2), and (3) are (21 C) 4.9 +- 1.0 mV, 7.14 +- 0.18 mV (aragonite/calcite), 19.11 +- 0.33 mV (vaterite/calcite), and 60.5 +- 1.3 mV, respectively. The equilibrium constant is calculated from these values of E0 for reactions one and three are 1.5 +- 0.1 and 116 +- 18, respectively. Also, the equilibrium constant for reaction one has been calculated for various simple models using statistical thermodynamics. The calculated and experimental values of the isotopic equilibrium constant are in disagreement

  9. Calcium - urine

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003603.htm Calcium - urine To use the sharing features on this ... enable JavaScript. This test measures the amount of calcium in urine. All cells need calcium in order ...

  10. Calcium supplements

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007477.htm Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

  11. Calcium Oscillations

    OpenAIRE

    Dupont, Geneviève; Combettes, Laurent; Bird, Gary S.; Putney, James W.

    2011-01-01

    Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlyin...

  12. Curing reaction of 4,4'-diaminodiphenyl methane and cardanol-based benzoxazine blends%4,4'-二氨基二苯甲烷/腰果酚-二胺型苯并恶嗪体系的固化

    Institute of Scientific and Technical Information of China (English)

    余银华; 孔逸然; 夏益青; 凌红; 顾宜

    2015-01-01

    4,4'-二氨基二苯甲烷(MDA)为固化剂,制备了腰果酚-二胺型苯并恶嗪与4,4'-二氨基二苯甲烷共混体系(MY-MDA).采用粘度测试,示差扫描量热分析和红外光谱研究了MY-MDA体系的的固化反应.结果表明,MDA与MY发生了共聚反应,降低了固化温度,使体系的粘度有效增长.MY-MDA体系的固化过程中存在2种不同的反应,即MDA与MY的共聚反应和MY自身热开环固化反应.随着MDA含量的增大,这2个反应的表观活化能和固化热焓呈现相反的变化趋势.

  13. Preparation, characterization of Mo catalysts supported on Ni- containing calcium deficient hydroxyapatite and reactivity for the thiophene HDS reaction

    Directory of Open Access Journals (Sweden)

    Cherif A.

    2013-09-01

    Full Text Available Ni-containing Calcium Hydroxyapatite (NiCaHAp; 3.31 wt.% Ni was synthesized by coprecipitation and used as catalyst support. Molybdenum was supported on NiCaHAp by impregnation using ammonium heptamolybdate. The prepared catalysts Mo(x/NiCaHAp (x: 2 to 8 wt % in Mo were characterized by elemental analysis, XRD, FT-IR, N2 adsorption-desorption and TEM-EDX. The catalysts were sulfided in-situ at 673 K under flowing H2S/H2 (15 Vol.% H2S and tested in hydrodesulfurization (HDS of thiophene at 673 K. The main XRD peaks of hydroxyapatite CaHAp phase were observed in all samples and a peak due probably to crystalline MoO3 phase was also identified from the results. However, no crystalline phase of NiO was found for the catalysts, which showed its Ni species were highly dispersed. The sulfided catalysts Mo(x/NiCaHAp presented are active in HDS of thiophene, despite the presence of some large MoO3 crystallites and incomplete sulfidation. This activity may be due to interaction of NiO and MoO3 on CaHAp resulting in the formation of Ni-Mo-S phase under flowing H2S/H2. When the molybdenum content increased the HDS activity increasead slightly, which was caused by the agglomeration of MoO3. The Mo(8/NiCaHAp catalyst is about two times less active for thiophene HDS than the commercial NiMoP/Al2O3.

  14. Characterization of the Diamant detector array from the de-excitation by emission of two particles of the 44Ti nuclei in the reaction 16O + 28Si at 50 MeV and 60 MeV

    International Nuclear Information System (INIS)

    We have characterized the response of the charged particle detector array DIAMANT in the reaction 16O + 28Si at 50 MeV and 60 MeV. We were able to select and study the deexcitation of the two particle channels for which the relative cross section is of the order of a few percent. The study of the energy distribution and the angular correlation of the emitted particles allowed a detailed test of the statistical model. The analysis of the results shows, for the first time, specific characteristics of the alpha particle emission from high spin states of the 44Ti compound nucleus formed in the reaction. (author)

  15. Activity diagrams for calcium/hydrogen, sodium/hydrogen, and potassium/hydrogen, and H4SiO4 and their relation to reactions in systems containing radioactive waste forms, cement, and rock in the presence of water

    International Nuclear Information System (INIS)

    In order to identify reactions which can occur in systems containing nuclear waste forms, cement, and repository rock in the presence of water, activity diagrams were calculated from free energies for aluminosilicates and calcium silicates. Groundwater compositions from candidate repository sites in the Palo Duro Basin of Texas, the Delaware Basin of New Mexico, and the Nevada Test Site were plotted on these diagrams. Essentially all of these are shown to be in the calcium zeolite field as shown on the diagram for calcium in the absence of other cations. Chlorite is shown to be stable in this region at the Mg and pH level of the Ogallala if the chlorite is high in iron, and at the Mg and pH level of the Wolfcamp low- or high-Fe chlorites are stable. Potassium and sodium mineral relationships fall in two categories, dilute waters and saline waters. Boreholes at Yucca Flat and Mercury Valley at the Nevada Test Site, and shallow ground water from the Rolling Plains north and east of the Palo Duro Basin are in equilibrium with kaolinite. The brines from the Salado and Rustler formations are in equilibrium with kaolinite and possibly also with sodium-potassium zeolite and illite. Leachates of cement and water, and cement, waste, and water were plotted on the calcium silicate activity diagram. These solutions are in equilibrium with calcium silicate hydrate hydrolysis reactions, with grossular and possibly with Ca-zeolites. Among the calcium silicates, calcium-silicate-hydrate gel (C-S-H gel) and tobermorite are the most likely candidates, but the thermodynamic data are not adequate to distinguish all the possibilities. 37 references, 4 figures, 3 tables

  16. Reactions Involving Calcium and Magnesium Sulfates as Potential Sources of Sulfur Dioxide During MSL SAM Evolved Gas Analyses

    Science.gov (United States)

    McAdam, A. C.; Knudson, C. A.; Sutter, B.; Franz, H. B.; Archer, P. D., Jr.; Eigenbrode, J. L.; Ming, D. W.; Morris, R. V.; Hurowitz, J. A.; Mahaffy, P. R.; Navarro-Gonzalez, R.

    2016-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) have analyzed several subsamples of 860 C). Sulfides or Fe sulfates were detected by CheMin (e.g., CB, MJ, BK) and could contribute to the high temperature SO2 evolution, but in most cases they are not present in enough abundance to account for all of the SO2. This additional SO2 could be largely associated with x-ray amorphous material, which comprises a significant portion of all samples. It can also be attributed to trace S phases present below the CheMin detection limit, or to reactions which lower the temperatures of SO2 evolution from sulfates that are typically expected to thermally decompose at temperatures outside the SAM temperature range (e.g., Ca and Mg sulfates). Here we discuss the results of SAM-like laboratory analyses targeted at understanding this last possibility, focused on understanding if reactions of HCl or an HCl evolving phase (oxychlorine phases, chlorides, etc.) and Ca and Mg sulfates can result in SO2 evolution in the SAM temperature range.

  17. Zona pellucida from fertilised human oocytes induces a voltage-dependent calcium influx and the acrosome reaction in spermatozoa, but cannot be penetrated by sperm

    Directory of Open Access Journals (Sweden)

    Jouannet Pierre

    2006-12-01

    Full Text Available Abstract Background The functions of three zona glycoproteins, ZP1, ZP2 and ZP3 during the sperm-zona pellucida (ZP interaction are now well established in mice. The expression of an additional zona glycoprotein, ZPB/4, in humans, led us to reconsider the classical mouse model of gamete interaction. We investigated the various functions of human ZP (hZP during the interaction of spermatozoa with fertilised and unfertilised oocytes. Results The hZP of fertilised oocytes retained their ability to bind sperm (albeit less strongly than that from unfertilised oocytes, to induce an intraspermatic calcium influx through voltage-dependent channels similar to that observed with hZP from unfertilised oocytes and to promote the acrosome reaction at a rate similar to that induced by the ZP of unfertilised oocytes (61.6 ± 6.2% vs60.7 ± 9.1% respectively. Conversely, the rate of hZP penetrated by sperm was much lower for fertilised than for unfertilised oocytes (19% vs 57% respectively, p Conclusion The change in ZP function induced by fertilisation could be different in human and mouse species. Our results suggest a zona blocking to polyspermy based at the sperm penetration level in humans.

  18. The opening of maitotoxin-sensitive calcium channels induces the acrosome reaction in human spermatozoa: differences from the zona pellucida

    Institute of Scientific and Technical Information of China (English)

    Julio C Chávez; Claudia L Trevi(n)o; Gerardo A de Blas; José L de la Vega-Beltrán; Takuya Nishigaki; Mayel Chirinos; María Elena González-González; Fernando Larrea; Alejandra Solís; Alberto Darszon

    2011-01-01

    The acrosome reaction(AR),an absolute requirement for spermatozoa and egg fusion,requires the influx of Ca2+into the spermatozoa through voltage-dependent Ca2+channels and store-operated channels.Maitotoxin(MTx),a Ca2+-mobilizing agent,has been shown to be a potent inducer of the mouse sperm AR,with a pharmacology similar to that of the zona pellucida(ZP),possibly suggesting a common pathway for both inducers.Using recombinant human ZP3(rhZP3),mouse ZP and two MTx channel blockers(U73122 and U73343),we investigated and compared the MTx-and ZP-induced ARs in human and mouse spermatozoa.Herein,we report that MTx induced AR and elevated intracellular Ca2+([Ca2+]1)in human spermatozoa,both of which were blocked by U73122 and U73343.These two compounds also inhibited the MTx-induced AR in mouse spermatozoa.In disagreement with our previous proposal,the AR triggered by rhZP3 or mouse ZP was not blocked by U73343,indicating that in human and mouse spermatozoa,the AR induction by the physiologicalligands or by MTx occurred through distinct pathways.U73122,but not U73343(inactive analogue),can block phospholipase C(PLC).Another PLC inhibitor,edelfosine,also blocked the rhZP3-and ZP-induced ARs.These findings confirmed the participation of a PLC-dependent signalling pathway in human and mouse zona protein-induced AR.Notably,edelfosine also inhibited the MTx-induced mouse sperm AR but not that of the human,suggesting that toxin-induced AR is PLC-dependent in mice and PLC-independent in humans.

  19. Peripheral collisions in Ar induced reactions between 27 and 44 A.MeV: study of energy dissipation by measuring the correlated neutron multiplicities

    International Nuclear Information System (INIS)

    A 4 π detector measuring the neutron multiplicities has been used to investigate the energy dissipation during peripheral collisions in Ar induced reactions around the Fermi Energy. Besides the persistance of direct transfer reactions for the most peripheral collisions, there are strong evidences for the occurrence of quite large energy dissipation, a clear signature for the one body friction to still play a major role at these intermediate energies

  20. Effect of calcium ion on reaction of potassium permanganate and natural organic matter%钙离子对高锰酸钾与天然有机物反应的影响

    Institute of Scientific and Technical Information of China (English)

    王晓荣; 陈忠林; 王斌远; 沈吉敏

    2011-01-01

    利用单宁酸做为天然有机物的代表研究了高锰酸钾与天然有机物的反应,考察了钙离子及钙离子和高锰酸钾不同投加顺序的影响及机理,并利用FTIR对反应进行了光谱学研究.结果表明,高锰酸钾与单宁酸反应生成可溶性分子,钙离子和高锰酸钾不同投加顺序对二者反应有一定的影响,先投加钙离子再投加高锰酸钾,溶液UV276.5的降低较多一些,DOC去除率较高一些,反应较充分.钙离子存在时单宁酸与高锰酸钾反应后生成大量固体成分,FTIR光谱的结果证实了此作用现象和机理.因此钙离子和有机物形成络合物,影响高锰酸钾与水中天然有机物的反应.%The reaction of potassium permanganate and natural organic matter was investigated. Effect of calcium ion and different dosing order of calcium and potassium permanganate were studied. FTIR spectra was employed for further spectroscopy study. Results showed that the reaction product of potassium permanganate and tannic acid were some soluble organic material, different dosing order of calcium and potassium permanganate has effect on the reaction. The addition of potassium permanganate after calcium presented the result of lower UV276.5 and DOC. FTIR spectra results showed that calcium ion increases the quantity of solid product. Consequently, it indicated that calcium ion chelates with organic matter and has important effect on the reaction of potassium permanganate and natural organic material.

  1. Improved sinterability and conductivity enhancement of 10-mol% calcium-doped ceria using different fuel-aided combustion reactions and its structural characterisation

    International Nuclear Information System (INIS)

    Highlights: • The analysis of the combustion parameters for different fuel-aided combustion syntheses of Ce0.9Ca0.1O1.9 is investigated. • The influence of fuel and its direct correlation with calculated thermochemistry is studied. • A complex reaction equation based on stoichiometric mole of fuels to propellant chemistry concept is created. • The influence of fuel utilised on the combustion process and on physiochemical properties is examined. • Ce0.9Ca0.1O1.9 ceramic from citric acid-aided combustion synthesis showed the highest conductivity (σ800°c = 0.017 S cm−1). - Abstract: Cubic fluorite structure of ceria doped with 10-mol% calcium, Ce0.9Ca0.1O1.9, was prepared using fuel-aided combustion techniques, utilising glycine, urea and citric acid as fuels along with metal nitrates as the oxidiser. The influence of fuel utilised on the combustion process and on physiochemical properties was thoroughly studied. The results of X-ray diffraction showed that all powders calcined at 400 °C were of single phase with cubic fluorite structure. Conductivity optimisation was achieved via ceramic sintering at various temperatures within 1000–1200 °C. The results showed that Ce0.9Ca0.1O1.9 ceramic prepared using citric acid-aided combustion synthesis had higher ionic conductivity, σ800°c = 0.017 S cm−1, and lower activation energy, Ea = 0.84 eV, compared to Ce0.9Ca0.1O1.9 ceramics prepared using glycine and urea. The scanning electron microscopy (SEM) results showed that pellets sintered at 1200 °C were dense, and the relative densities of these pellets were over 95%, determined using the Archimedes method

  2. Difference in surface reactions between titanium and zirconium in Hanks' solution to elucidate mechanism of calcium phosphate formation on titanium using XPS and cathodic polarization

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Y.; Nishimura, D.; Doi, H.; Nomura, N. [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Hanawa, T., E-mail: hanawa.met@tmd.ac.jp [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan)

    2009-06-01

    Titanium and zirconium were immersed in Hanks' solution with and without calcium and phosphate ions, and the surfaces were characterized with X-ray photoelectron spectroscopy (XPS) to determine the mechanism of calcium phosphate formation on titanium in simulated body fluids and in a living body. In addition, they were cathodically polarized in the above solutions. XPS characterization and cathodic polarization revealed differences in the surface properties in the ability of calcium phosphate formation between titanium and zirconium. The surface oxide film on titanium is not completely oxidized and is relatively reactive; that on zirconium is more passive and protective than that on titanium. Neither calcium nor phosphate stably exists alone on titanium, and calcium phosphate is naturally formed on it; calcium phosphate formed on titanium is stable and protective. On the other hand, calcium is never incorporated on zirconium, while zirconium phosphate, which is easily formed on zirconium, is highly stable and protective. Our study presents new information regarding the surface property of titanium and demonstrates that the characteristics of titanium and zirconium may be applied to various medical devices and new surface modification techniques.

  3. Difference in surface reactions between titanium and zirconium in Hanks' solution to elucidate mechanism of calcium phosphate formation on titanium using XPS and cathodic polarization

    International Nuclear Information System (INIS)

    Titanium and zirconium were immersed in Hanks' solution with and without calcium and phosphate ions, and the surfaces were characterized with X-ray photoelectron spectroscopy (XPS) to determine the mechanism of calcium phosphate formation on titanium in simulated body fluids and in a living body. In addition, they were cathodically polarized in the above solutions. XPS characterization and cathodic polarization revealed differences in the surface properties in the ability of calcium phosphate formation between titanium and zirconium. The surface oxide film on titanium is not completely oxidized and is relatively reactive; that on zirconium is more passive and protective than that on titanium. Neither calcium nor phosphate stably exists alone on titanium, and calcium phosphate is naturally formed on it; calcium phosphate formed on titanium is stable and protective. On the other hand, calcium is never incorporated on zirconium, while zirconium phosphate, which is easily formed on zirconium, is highly stable and protective. Our study presents new information regarding the surface property of titanium and demonstrates that the characteristics of titanium and zirconium may be applied to various medical devices and new surface modification techniques.

  4. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Moilanen, A.; Norby, P.; Papadakis, K.; Posselt, D.; Sørensen, L. H.

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...

  5. Improved sinterability and conductivity enhancement of 10-mol% calcium-doped ceria using different fuel-aided combustion reactions and its structural characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Ong, P.S., E-mail: pohshing@gmail.com [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Tan, Y.P., E-mail: yptan@science.upm.edu.my [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Putra Laboratory for Catalysis Science and Technology, Department Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Taufiq-Yap, Y.H., E-mail: yap@science.upm.edu.my [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Putra Laboratory for Catalysis Science and Technology, Department Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Zainal, Z., E-mail: zulkar@science.upm.edu.my [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Putra Laboratory for Catalysis Science and Technology, Department Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2014-07-01

    Highlights: • The analysis of the combustion parameters for different fuel-aided combustion syntheses of Ce{sub 0.9}Ca{sub 0.1}O{sub 1.9} is investigated. • The influence of fuel and its direct correlation with calculated thermochemistry is studied. • A complex reaction equation based on stoichiometric mole of fuels to propellant chemistry concept is created. • The influence of fuel utilised on the combustion process and on physiochemical properties is examined. • Ce{sub 0.9}Ca{sub 0.1}O{sub 1.9} ceramic from citric acid-aided combustion synthesis showed the highest conductivity (σ{sub 800°c} = 0.017 S cm{sup −1}). - Abstract: Cubic fluorite structure of ceria doped with 10-mol% calcium, Ce{sub 0.9}Ca{sub 0.1}O{sub 1.9}, was prepared using fuel-aided combustion techniques, utilising glycine, urea and citric acid as fuels along with metal nitrates as the oxidiser. The influence of fuel utilised on the combustion process and on physiochemical properties was thoroughly studied. The results of X-ray diffraction showed that all powders calcined at 400 °C were of single phase with cubic fluorite structure. Conductivity optimisation was achieved via ceramic sintering at various temperatures within 1000–1200 °C. The results showed that Ce{sub 0.9}Ca{sub 0.1}O{sub 1.9} ceramic prepared using citric acid-aided combustion synthesis had higher ionic conductivity, σ{sub 800°c} = 0.017 S cm{sup −1}, and lower activation energy, E{sub a} = 0.84 eV, compared to Ce{sub 0.9}Ca{sub 0.1}O{sub 1.9} ceramics prepared using glycine and urea. The scanning electron microscopy (SEM) results showed that pellets sintered at 1200 °C were dense, and the relative densities of these pellets were over 95%, determined using the Archimedes method.

  6. 化工废料过磷酸钙在植物秸秆沤肥中的应用%Application of Calcium Superphosphate as Chemical Waste in the Reaction of Plant Straw Wet Compost

    Institute of Scientific and Technical Information of China (English)

    王庆雨; 林楷

    2016-01-01

    In order to investigate the influence of the chemical waste calcium superphosphate on the nitrogen loss rate and the maturity time in the reaction of plant straw wet compost, using straws, melon vines, rotten vegetables leaves, weeds and animal manures as raw materials, and using the chemical waste calcium superphosphate as additive, the reaction of wet compost was carried out in the homemade equipment. The results show that the chemical waste calcium superphosphate is helpful to reduce the loss of N and shorten the maturity time. After plant straw wet compost for 20 days, the nitrogen loss rate and germination index of the wet compost without the chemical waste calcium superphosphate are 35.8% and 64.3%, respectively, while the nitrogen loss rate and germination index of the wet compost adding the chemical waste calcium superphosphate are 15.2% and 82.8%, respectively. Good application effect of the chemical waste calcium superphosphate has been achieved in plant straw wet compost process.%为研究化工废料过磷酸钙对植物秸秆沤肥过程中氮损失率和腐熟时间的影响,以秸秆、瓜蔓、烂菜叶、杂草、畜肥为原材料,以化工废料过磷酸钙为添加剂,在自制的装置中进行沤肥。结果表明:化工废料过磷酸钙有助于减少氮的损失,缩短沤肥腐熟时间。沤肥20 d 后,沤肥过程中未添加化工废料过磷酸钙的氮损失率为35.8%,发芽指数为64.3%;而添加了化工废料过磷酸钙的氮损失率为15.2%,发芽指数为82.8%。化工废料过磷酸钙在植物秸秆沤肥过程取得了良好的应用效果。

  7. Effects of pH value of reaction solution on structure and electrochemical performance of calcium-containing active material of secondary zinc electrodes

    Institute of Scientific and Technical Information of China (English)

    陈华; 王建明; 郑奕; 张鉴清; 曹楚南

    2004-01-01

    The calcium-containing active material of secondary alkaline zinc electrodes was prepared by a chemical coprecipitation method and characterized by scanning electron microscopy(SEM) and X-ray diffractometry(XRD).Their electrochemical performance was tested by the Galvanstatic charge-discharge method. The experimental results show that the sample synthesized at pH = 11.15 has a typical calcium zincate crystal. The zinc electrode using this sample as active material shows higher discharge capacity, more negative discharge plateau potential and longer cycle lifetime.

  8. Diagnosis and assessment of skeletal related disease using calcium 41

    Science.gov (United States)

    Hillegonds, Darren J.; Vogel, John S.; Fitzgerald, Robert L.; Deftos, Leonard J.; Herold, David; Burton, Douglas W.

    2012-05-15

    A method of determining calcium metabolism in a patient comprises the steps of administering radioactive calcium isotope .sup.41Ca to the patient, allowing a period of time to elapse sufficient for dissemination and reaction of the radioactive calcium isotope .sup.41Ca by the patient, obtaining a sample of the radioactive calcium isotope .sup.41Ca from the patient, isolating the calcium content of the sample in a form suitable for precise measurement of isotopic calcium concentrations, and measuring the calcium content to determine parameters of calcium metabolism in the patient.

  9. Calcium Carbonate

    Science.gov (United States)

    ... before being swallowed; do not swallow them whole. Drink a full glass of water after taking either the regular or chewable tablets or capsules. Some liquid forms of calcium carbonate must be shaken well before use.Do not ...

  10. Calcium Electroporation

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gibot, Laure; Madi, Moinecha;

    2015-01-01

    BACKGROUND: Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill...... efficacy-and normal cell sensitivity. METHODS: Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780......), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). RESULTS: The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p<0.0001) or...

  11. Calcium Calculator

    Science.gov (United States)

    ... Latvia - Lebanon - Libya - Lithuania - Luxembourg - Macedonia, Republic of - Malaysia - Malta - Mexico - Moldova - Morocco - Netherlands - New Zealand - Nigeria - ... and Statistics Popular content Calcium content of common foods What is Osteoporosis? The Board Introduction to Bone ...

  12. Cyclotron production of high purity 44m,44Sc with deuterons from 44CaCO3 targets

    International Nuclear Information System (INIS)

    Introduction: Due to its longer half-life, 44Sc (T1/2 = 3.97 h) as a positron emitter can be an interesting alternative to 68Ga (T1/2 = 67.71 min). It has been already proposed as a PET radionuclide for scouting bone disease and is already available as a 44Ti/44Sc generator. 44Sc has an isomeric state, 44mSc (T1/2 = 58.6 h), which can be co-produced with 44Sc and that has been proved to be considered as an in-vivo PET generator 44mSc/44Sc. This work presents the production route of 44mSc/44Sc generator from 44Ca(d,2n), its extraction/purification process and the evaluation of its performances. Methods: Irradiation was performed in a low activity target station using a deuteron beam of 16 MeV, which favors the number of 44mSc atoms produced simultaneously to 44Sc. Typical irradiation conditions were 60 min at 0.2 μA producing 44 MBq of 44Sc with a 44Sc/44mSc activity ratio of 50 at end of irradiation. Separations of the radionuclides were performed by means of cation exchange chromatography using a DGA® resin (Triskem). Then, the developed process was applied with bigger targets, and could be used for preclinical studies. Results: The extraction/purification process leads to a radionucleidic purity higher than 99.99% (43Sc, 46Sc, 48Sc < DL). 44mSc/44Sc labeling towards DOTA moiety was performed in order to get an evaluation of the specific activities that could be reached with regard to all metallic impurities from the resulting source. Reaction parameters of radiolabeling were optimized, reaching yields over 95%, and leading to a specific activity of about 10–20 MBq/nmol for DOTA. A recycling process for the enriched 44Ca target was developed and optimized. Conclusion: The quality of the final batch with regard to radionucleidic purity, specific activity and metal impurities allowed a right away use for further radiopharmaceutical evaluation. This radionucleidic pair of 44mSc/44Sc offers a quite interesting PET radionuclide for being further evaluated as an in

  13. Cyclotron production of {sup 44}Sc for clinical application

    Energy Technology Data Exchange (ETDEWEB)

    Krajewski, S.; Bilewicz, A. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Cydzik, I. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); European Commission Joint Research Center, Ispra (Italy). Inst. for Health and Consumer Protection; Warsaw Univ. (Poland). Heavy Ion Lab.; Abbas, K. [European Commission Joint Research Center, Ispra (Italy). Institute for Transuranium Elements; Bulgheroni, A.; Simonelli, F.; Holzwarth, U. [European Commission Joint Research Center, Ispra (Italy). Inst. for Health and Consumer Protection

    2013-08-01

    {sup 44} is a promising {beta}{sup +}-emitter for molecular imaging with intermediate half-life of 4 h. Due to the chemical similarity of Sc{sup 3+} to the Lu{sup 3+} and Y{sup 3+} cations, {sup 44}Sc-DOTA bioconjugates are expected to demonstrate similar properties in vivo as the {sup 177}Lu- and {sup 90}Y-bioconjugates, what is important in planning the radionuclide therapy. {sup 44}Sc can be obtained from the {sup 44}Ti/{sup 44}Sc generator. An alternative method for {sup 44}Sc production can be the irradiation of {sup 44}Ca target at small cyclotrons. The aim of our work was to optimize the parameters of {sup 44}CaCO{sub 3} irradiation and to develop a simple procedure for {sup 44}Sc separation from the calcium target. For optimization study, {sup 44}CaCO{sub 3} targets were irradiated by protons in the energy range of 5.6-17.5 MeV with 9 MeV being found to be the best energy for {sup 44}Ca irradiations. A simple and fast separation procedure of {sup 44}Sc from calcium target was developed using chelating resin Chelex 100. DOTATATE conjugate was successfully radiolabelled with high yield at elevated temperature using the produced {sup 44}Sc. While {sup 44}CaCO{sub 3} is relatively expensive, the cost of {sup 44}Sc-DOTATATE production can be reduced by target recovery. Due to low proton energy required to produce GBq activity level of {sup 44}Sc, the availability of {sup 44}Sc radioisotope could be enhanced to open new opportunities for applications in medical imaging. (orig.)

  14. Cyclotron production of 44Sc for clinical application

    International Nuclear Information System (INIS)

    44 is a promising β+-emitter for molecular imaging with intermediate half-life of 4 h. Due to the chemical similarity of Sc3+ to the Lu3+ and Y3+ cations, 44Sc-DOTA bioconjugates are expected to demonstrate similar properties in vivo as the 177Lu- and 90Y-bioconjugates, what is important in planning the radionuclide therapy. 44Sc can be obtained from the 44Ti/44Sc generator. An alternative method for 44Sc production can be the irradiation of 44Ca target at small cyclotrons. The aim of our work was to optimize the parameters of 44CaCO3 irradiation and to develop a simple procedure for 44Sc separation from the calcium target. For optimization study, 44CaCO3 targets were irradiated by protons in the energy range of 5.6-17.5 MeV with 9 MeV being found to be the best energy for 44Ca irradiations. A simple and fast separation procedure of 44Sc from calcium target was developed using chelating resin Chelex 100. DOTATATE conjugate was successfully radiolabelled with high yield at elevated temperature using the produced 44Sc. While 44CaCO3 is relatively expensive, the cost of 44Sc-DOTATATE production can be reduced by target recovery. Due to low proton energy required to produce GBq activity level of 44Sc, the availability of 44Sc radioisotope could be enhanced to open new opportunities for applications in medical imaging. (orig.)

  15. Calcium pyrophosphate arthritis

    Science.gov (United States)

    Calcium pyrophosphate dihydrate deposition disease; CPPD disease; Acute CPPD arthritis; Pseudogout ... Calcium pyrophosphate arthritis is caused by the collection of salt called calcium pyrophosphate dihydrate (CPPD). The buildup ...

  16. Light charged particle and neutron velocity spectra in coincidence with projectile fragments in the reaction sup 4 sup 0 Ar(44 A MeV)+ sup 2 sup 7 Al

    CERN Document Server

    Lanzanò, G; Geraci, M; Pagano, A; Aiello, S; Cunsolo, A; Fonte, R; Foti, A; Sperduto, M L; Volant, C; Charvet, J L; Dayras, R; Legrain, R

    2001-01-01

    We present a three source analysis of velocity spectra of light charged particles (LCP) and neutrons emitted in the reaction sup 4 sup 0 Ar+ sup 2 sup 7 Al at 44 A MeV. The light particle (LP) velocity spectra are studied as a function of the detection angle (1.5 deg.

  17. Mound Facility activities in chemical and physical research: January-June 1980. [OLECULES; VIRIAL EQUATION; CHEMICAL REACTIONS; DEUTERIUM; TRITIUM; CALCIUM NITRATES; HEAVY WATER; THERMAL DIFFUSION; WATER; CROSS SECTIONS; MOLECULAR BEAMS; TEMPERATURE DEPENDENCE; CHELATING AGENTS; CHLOROFORM

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-29

    I. Low temperature research covered Hydrogen Intermolecular Potential Functions: five potentials have been compared to bound state energies, second virial coefficients, and total and differential scattering cross sections, but none of them consistently fits all of the data. Using a Hartree-Fock-Dispersion form with a modified damping function, three out of the four sets of data can be represented with a single potential function. Reaction Rates of Deuterium-Tritium Mixtures: two mixing chambers are being designed and built for studying D/sub 2/-T/sub 2/ and H/sub 2/-T/sub 2/. Low Temperature Trennschaukel: a bench model trennschaukel has been instrumented. II. Separation research covered Liquid Thermal Diffusion: Isotopic separations as functions of time were measured for methyl chloride, ethyl chloride, 1-chloropropane and 1-chlorobutane. The campaign to enrich chlorine-37 by liquid thermal diffusion of methyl chloride was concluded after 240 g of enriched isotope had been produced. Calcium Isotope Separation: Calcium isotope separation in the Ca(NO/sub 3/)/sub 2/-H/sub 2/O and -D/sub 2/O systems was measured using a 36.5 cm liquid phase thermal diffusion column. The largest separation was a 15% change in the calcium-48 abundance. Molecular Beam Scattering: a supersonic Ne beam through a cell containing Ar was used to measure low-energy, elastic, total cross sections of neon/argon in the velocity range of 4 to 10 (x 10/sup 4/) cm/s. Cross sections at onset of clustering were 7% higher than at minimum cluster conditions. Mutual Diffusion: Study continues on the temperature dependence of the mutal diffusion coefficients for binary noble gas mixtures, particularly argon with helium, neon, and xenon. Metal Chemical Exchange With Macrocyclic Ligands: The equilibrium single-stage separation factor was determined for two additional LiTFA/221 cryptand/CHCl/sub 3/ and two LiTFA/211 cryptand/CHCl/sub 3/ exchange systems.

  18. Calcium and bones

    Science.gov (United States)

    Bone strength and calcium ... calcium (as well as phosphorus) to make healthy bones. Bones are the main storage site of calcium in ... your body does not absorb enough calcium, your bones can get weak or will not grow properly. ...

  19. Get Enough Calcium

    Science.gov (United States)

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of calcium ...

  20. Calcium carbonate overdose

    Science.gov (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  1. Calcium absorption from corn tortilla is relatively high and is dependent upon calcium content and liming in Mexican women.

    Science.gov (United States)

    Rosado, Jorge L; Díaz, Margarita; Rosas, Angélica; Griffit, Ian; García, Olga P

    2005-11-01

    Corn tortillas are the staple food of Mexico. During their preparation, calcium is added to the tortillas; therefore, tortillas are the main source of calcium for a large proportion of the population. The bioavailability of calcium from lime-treated tortillas in humans is not known. The objectives of the present study were to determine calcium absorption from corn tortilla, to determine the effect of lime treatment on calcium absorption from corn tortilla, and to compare calcium absorption from tortilla prepared with a commercial corn flour and tortillas prepared with the traditional lime treatment at home. Nonpregnant, nonlactating women (n = 9) were administered 3 different treatments: 1) 180 g of corn tortilla prepared from corn flour with no lime treatment (CF), 2) 180 g of corn tortilla prepared from lime-treated commercial corn flour (LTCCF), or 3) 180 g of corn tortillas prepared from lime-treated home-prepared corn flour (LTHCF). Calcium absorption was measured using an established dual-tracer stable isotope technique. Calcium absorption of CF, LTCCF, and LTHCF was (mean +/- SD): 44 +/- 3.2, 32 +/- 4.4, and 30 +/- 2.4%, respectively; the fractional calcium absorption from CF differed from that of either LTCCF or LTHCF (P tortillas is high and dependent on calcium concentration. The addition of calcium during lime treatment increases calcium concentration and total calcium absorption. PMID:16251614

  2. Production of edible carbohydrates from formaldehyde in a spacecraft. pH variations in the calcium hydroxide catalyzed formose reaction. Final Report, 1 Jul. 1973 - 30 Jun. 1974. M.S. Thesis

    Science.gov (United States)

    Weiss, A. H.; Kohler, J. T.; John, T.

    1974-01-01

    The study of the calcium hydroxide catalyzed condensation of formaldehyde was extended to a batch reactor system. Decreases in pH were observed, often in the acid regime, when using this basic catalyst. This observation was shown to be similar to results obtained by others using less basic catalysts in the batch mode. The relative rates of these reactions are different in a batch reactor than in a continuous stirred tank reactor. This difference in relative rates is due to the fact that at any degree of advancement in the batch system, the products have a history of previous products, pH, and dissolved catalyst. The relative rate differences can be expected to yield a different nature of product sugars for the two types of reactors.

  3. The Thermal Decomposition of Calcium Carbonate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The thermogravimetry(TG) and derivative thermogravimetry(DTG) curves of the thermal decomposition reaction of calcium carbonate have been measured at five different heating rates. The kinetic parameters and the reaction mechanism of the reaction were evaluated from analysis of the TG and DTG curves by using the Ozawa method, the combined integral and differential methods and the reduced equations derived by us.

  4. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Slade, A.M.; Nayler, W.G.; Meijler, F.L.

    1984-01-01

    Reperfusion of isolated hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). This phenomenon is characterized by an excessive influx of calcium into the cells, the rapid onset of myocardial contracture, exhausti

  5. Mechanistic spray dryer mathematical model based on film theory to predict sulfur dioxide absorption and reaction by a calcium hydroxide slurry in the constant rate period

    Energy Technology Data Exchange (ETDEWEB)

    Partridge, G.P. Jr.

    1987-01-01

    In the spray dryer, flue gas from a coal-fired boiler is contacted with an atomized lime slurry; during this contact SO/sub 2/ absorbs and reacts with dissolved Ca(OH)/sub 2/. The mathematical model developed in this activity superimposes SO/sub 2/ absorption and reaction phenomena on existing mathematical descriptions of spray dryer operation. The SO/sub 2/ removal appears to occur primarily in the constant rate period where a continuous liquid phase exists in the atomized slurry droplet. The constant rate period proceeds until evaporation has reduced the liquid phase volume to the point where the Ca(OH)/sub 2/ sorbent particles touch and the diffusion paths for reactants are restricted. The SO/sub 2/ absorption flux involves liquid phase as well as gas phase resistances. The liquid phase resistance includes mass transfer and chemical reaction phenomena associated with the absorption and reaction of SO/sub 2/ and Ca(OH)/sub 2/ and the dissolution of Ca(OH)/sub 2/. Instantaneous reaction occurs between SO/sub 2/ and Ca(OH)/sub 2/ in the liquid phase. Solid dissolution in the liquid film is unimportant and solid dissolution and reaction occur in series. A comprehensive model was developed for the constant rate period. The model is based on film theory and treats the atomized slurry droplet as a sphere of discrete sorbent particles with the fluid phase uniformly distributed around the individual sorbent particles. This concept allows prediction of the mass transfer coefficients and the enhancement due to increasing solids concentration as evaporation proceeds. Efficiency predicts using the model were compared with pilot plant data taken at different inlet flue gas temperatures, stoichiometric ratios and slurry flow rates.

  6. Gel time of calcium acrylate grouting material.

    Science.gov (United States)

    Han, Tong-Chun

    2004-08-01

    Calcium acrylate is a polymerized grout, and can polymerize in an aqueous solution. The polymerization reaction utilizes ammonium persulfate as a catalyst and sodium thiosulfate as the activator. Based on the theory of reaction kinetics, this study on the relation between gel time and concentration of activator and catalyst showed that gel time of calcium acrylate is inversely proportional to activator and catalyst concentration. A formula of gel time is proposed, and an example is provided to verify the proposed formula. PMID:15236477

  7. Correction of the N-terminal sequences of the human plastin isoforms by using anchored polymerase chain reaction: identification of a potential calcium-binding domain.

    OpenAIRE

    Lin, C. S.; Aebersold, R H; Leavitt, J

    1990-01-01

    Plastins are a family of at least three cytoplasmic protein isoforms that are expressed differentially between cells of the hematopoietic lineages and cells of solid tissues. Expression of the L-plastin isoform appears to be restricted to replicating blood cells, and the two T-plastin isoforms appear to be restricted to replicating cells of solid tissues. However, L-plastin is induced in many human solid tumor-derived cells. We used the anchored polymerase chain reaction technique to amplify ...

  8. Sources and controls of calcium and magnesium in storm runoff: the role of groundwater and ion exchange reactions along water flowpaths

    Directory of Open Access Journals (Sweden)

    P. J. Chapman

    1997-01-01

    Full Text Available A combined hydrological and chemical investigation was undertaken in a small moorland catchment at Plynlimon to determine the processes controlling storm runoff chemistry. Flow from natural soil pipes, overland flow from peat soils, throughflow from a mineral horizon and streamflow were gauged and sampled intensively during seven storms. Stormflow Ca and Mg concentrations in stream water consistently exceeded those observed in overland flow, pipeflow and throughflow. The response of Ca and Mg to increases in streamflow varied between the storms and could not be explained readily by the mixing of the dominant source waters monitored within the catchment. Intensive sampling of pipe water along a major stormflow pathway revealed a large and consistent increase in the concentration of dissolved Ca and Mg accompanied by a corresponding decrease in acidity, the magnitude of which was strongly influenced by antecedent conditions. Analyses of soil exchangeable cations along the stormflow pathway revealed soils enriched in divalent cations probably derived from a groundwater source. Laboratory leaching experiments confirmed that rapid cation exchange reactions could explain the changes in pipe water chemistry along the stormflow pathway. The relative contribution of flow from pathways where these ion exchange reactions occur strongly influences the stormflow response of Ca and Mg in the stream. The results also highlight a potentially important, indirect role for base-rich groundwater in modifying storm runoff chemistry along water flowpaths.

  9. Calcium isotope ratios in animal and human bone

    Science.gov (United States)

    Reynard, L. M.; Henderson, G. M.; Hedges, R. E. M.

    2010-07-01

    Calcium isotopes in tissues are thought to be influenced by an individual's diet, reflecting parameters such as trophic level and dairy consumption, but this has not been carefully assessed. We report the calcium isotope ratios (δ 44/42Ca) of modern and archaeological animal and human bone ( n = 216). Modern sheep raised at the same location show 0.14 ± 0.08‰ higher δ 44/42Ca in females than in males, which we attribute to lactation by the ewes. In the archaeological bone samples the calcium isotope ratios of the herbivorous fauna vary by location. At a single site, the archaeological fauna do not show a trophic level effect. Humans have lower δ 44/42Ca than the mean site fauna by 0.22 ± 0.22‰, and the humans have a greater δ 44/42Ca range than the animals. No effect of sex or age on the calcium isotope ratios was found, and intra-individual skeletal δ 44/42Ca variability is negligible. We rule out dairy consumption as the main cause of the lower human δ 44/42Ca, based on results from sites pre-dating animal domestication and dairy availability, and suggest instead that individual physiology and calcium intake may be important in determining bone calcium isotope ratios.

  10. Synthesis of calcium hydroxyapatite from calcium carbonate and different orthophosphate sources: A comparative study

    International Nuclear Information System (INIS)

    Highlights: ► Calcium hydroxyapatite was synthesized from CaCO3 and four orthophosphates. ► Only H3PO4 led to the complete precipitation of orthophosphate species. ► H3PO4 was also the most efficient for calcium dissolution. ► Reaction pathway was dissolution-precipitation accompanied by agglomeration step. - Abstract: The synthesis of calcium hydroxyapatite (Ca-HA) starting from calcium carbonate and different orthophosphate sources, including orthophosphoric acid, potassium, sodium and ammonium dihydrogen orthophosphates, was investigated under ambient conditions. The reaction started with calcium carbonate dissolution in an acid medium, followed by rapid precipitation of calcium cations with orthophosphate species to form calcium phosphate based particles which were in the size range of 0.4–1 μm. These particles then agglomerated into much larger ones, up to 350 μm in diameter (aggregates). These aggregates possessed an unstable porous structure which was responsible for the porosity of the final products. The highest specific surface area and pore volume were obtained with potassium dihydrogen orthophosphate. On the other hand, orthophosphoric acid led to the highest dissolution of calcium carbonate and the complete precipitation of orthophosphate species. Under ambient conditions, calcium phosphate based solid products of low crystallinity were formed. Different intermediates were identified and a reaction pathway proposed.

  11. I. Nuclear Production Reaction and Chemical Isolation Procedure for Americium-240 II. New Superheavy Element Isotopes: Plutonium-242(Calcium-48,5n)(285)114

    Science.gov (United States)

    Ellison, Paul Andrew

    2011-12-01

    Part I discusses the study of a new nuclear reaction and chemical separation procedure for the production of 240Am. Thin 242Pu, natTi, and natNi targets were coincidently activated with protons from the 88-Inch Cyclotron, producing 240Am, 48V, and 57Ni, respectively. The radioactive decay of these isotopes was monitored using high-purity Ge gamma ray detectors in the weeks following irradiation. The excitation function for the 242 Pu(p, 3n)240Am nuclear reaction was measured to be lower than theoretical predictions, but high enough to be the most viable nuclear reaction for the large-scale production of 240 Am. Details of the development of a chemical separation procedure for isolating 240Am from proton-irradiated 242Pu are discussed. The separation procedure, which includes two anion exchange columns and two extraction chromatography columns, was experimentally investi- gated using tracer-level 241Am, 239Pu, and model proton-induced fission products 95Zr, 95Nb, 125Sb, and 152Eu. The separation procedure was shown to have an Am/Pu separation factor of >2x10 7 and an Am yield of ˜70%. The separation procedure was found to purify the Am sample from >99.9% of Eu, Zr, Nb, and Sb. The procedure is well suited for the processing of ˜1 gram of proton-irradiated 242Pu to produce a neutron-induced fission target consisting of tens of nanograms of 240Am. Part II describes the use of the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron for the study of the 242Pu(48Ca,5n)285114 nuclear re- action. The new, neutron-deficient, superheavy element isotope 285114 was produced in 48Ca irradiations of 242Pu targets at a center-of-target beam energy of 256 MeV ( E* = 50 MeV). The alpha decay of 285114 was followed by the sequential alpha decay of four daughter nuclides, 281Cn, 277Ds, 273Hs, and 269 Sg. 265Rf was observed to decay by spontaneous fission. The measured alpha-decay Q-values were compared with those from a macroscopic

  12. Calcium and bones (image)

    Science.gov (United States)

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  13. Coronary Calcium Scan

    Science.gov (United States)

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  14. Calcium hydroxide poisoning

    Science.gov (United States)

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  15. Calcium source (image)

    Science.gov (United States)

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  16. Calcium in diet

    Science.gov (United States)

    Diet - calcium ... Calcium is one of the most important minerals for the human body. It helps form and maintain healthy teeth and bones. A proper level of calcium in the body over a lifetime can help ...

  17. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  18. 木素稀硝酸氧化及其与磷酸钙作用的研究%Study on oxidation of lignin by nitric acid and its reaction with calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    马子川; 崔振水

    2001-01-01

    研究了造纸黑液木素稀硝酸氧化法制备活性氧化木素的适宜条件。结果表明,当磷酸含量为4.0%,木素与稀硝酸的质量配比为1∶10,可得到腐殖酸含量达46%的氧化木素。研究了氧化木素和氨化氧化木素对3种磷酸钙的溶解性的影响,讨论并合理地解释了反应机理。%Optimal conditions for preparation of active lignin oxide by oxidizing black-liquor lignin with nitric acid were studied.The results showed that the yield of lignin oxide was up to 46% when the concentration of phosphoric acid was under 4.0%,and the mass ratio of lignin to diluted nitric acid was 1∶10.Effects on solubilities of three kinds of calcium phosphate and ammoniated oxidized lignin were observed and reasonable reaction mechanism was discussed.

  19. Relating a calcium indicator signal to the unperturbed calcium concentration time-course

    Directory of Open Access Journals (Sweden)

    Abarbanel Henry DI

    2007-02-01

    Full Text Available Abstract Background Optical indicators of cytosolic calcium levels have become important experimental tools in systems and cellular neuroscience. Indicators are known to interfere with intracellular calcium levels by acting as additional buffers, and this may strongly alter the time-course of various dynamical variables to be measured. Results By investigating the underlying reaction kinetics, we show that in some ranges of kinetic parameters one can explicitly link the time dependent indicator signal to the time-course of the calcium influx, and thus, to the unperturbed calcium level had there been no indicator in the cell.

  20. Hardening of calcium hydroxide and calcium silicate binders due to carbonation and hydration

    OpenAIRE

    Cizer, Özlem; Campforts, J; Balen, Koenraad Van; Elsen, Jan; Gemert, Dionys van

    2006-01-01

    Hardening of calcium hydroxide and calcium silicate binders composed of cement, rice husk ash (RHA) and lime in different compositions were studied with mechanical strength, mercury intrusion porosimetry, thermal analysis and SEM. When cement is partially replaced with RHA and lime, hardening occurs as a result of combined hydration, pozzolanic reaction and carbonation reaction. While hydration of cement contributes to the early strength development of the mortars, carbonation is much more pr...

  1. L-lactide ring open polymerization with catalyst based on calcium compounds; Polimerizacao via abertura de anel de L-lactideo com compostos a base de calcio

    Energy Technology Data Exchange (ETDEWEB)

    Palermo, Luiz C.M.; Dias, Marcos L.; Silvino, Alexandre C. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Professora Eloisa Mano

    2009-07-01

    The bulk ring opening polymerization of L-lactide using calcium methoxide and calcium octoate as catalysts at different lactide/calcium (LA:Ca) molar ratio was investigated. The reactions were carried out at LA:Ca ratio of 100, 250, 500, 1,000 and 5,000 at 180 deg C. The poly(L-lactic acid) (PLLA) were characterized according the molecular weight, microstructure and thermal properties. Higher polymerization yields was 66 wt % in the LA:Ca ratio= 100. The polydispersity ranged from 1.20 to 1.44 and the molecular weight varied from 8,500 to 19,500. Results of X-ray diffraction indicated that the polymers present high crystallinity, particularly the PLLA obtained with LA:Ca molar ration= 1,000 and 5,000. (author)

  2. Groundwater chemistry and cation budgets of tropical karst outcrops, Peninsular Malaysia, I. Calcium and magnesium

    Science.gov (United States)

    Crowther, J.

    1989-05-01

    The discharge and chemical properties of 217 autogenic groundwaters were monitored over a 1-yr period in the tower karsts of central Selangor and the Kinta Valley, and in the Setul Boundary Range. Because of differences in soil PCO 2, calcium concentrations are significantly higher in the Boundary Range (mean, 82.5 mg l -1) than in the tower karst terrain (44.6 mg l -1). Local differences in both source area PCO 2 and amounts of secondary deposition underground cause marked intersite variability, particularly in the tower karst. Dilution occurs during flood peaks in certain conduit and cave stream waters. Generally, however, calcium correlates positively with discharge, since the amount of secondary deposition per unit volume of water decreases at higher flows. Magnesium concentrations and Mg:Ca + Mg ratios of groundwaters are strongly influenced by bedrock composition, though bedrock heterogeneity and the kinetics and equilibria of carbonate dissolution reactions preclude extremely low or high Mg:Ca + Mg values. Net chemical denudation rates range from 56.6 to 70.9 m 3km 2yr -1. The results are considered in relation to cation fluxes in surface runoff, soil throughflow and nutrient cycling. Preliminary calcium and magnesium budgets show that (1) dissolutional activity is largely confined to the near-surface zone; and (2) the annual uptake of calcium and magnesium by tropical limestone forests is similar in magnitude to the net solute output in groundwaters.

  3. Effect of Calcium on the Vanadium Extraction from High Calcium Type Stone Coal

    Institute of Scientific and Technical Information of China (English)

    BAO Shenxu; LIANG Liang; ZHANG Yimin; HAN Shihua; HU Yangjia

    2015-01-01

    The high calcium type stone coal from Hubei province was leached by water and dilute acid separately after being roasted with different dosage of NaCl. The water leaching rate of vanadium (WLRV) was low and only 26.8%of vanadium can be leached by water when 4%NaCl was added, but the acid leaching rate of vanadium (ALRV) was relatively high. Calcium in the high calcium type stone coal is greatly superfluous relative to vanadium, hence, the calcium reacts with vanadium to form Ca(VO3)2, Ca2V2O7 and Ca3(VO4)2 orderly during the stone coal roasting process and high temperature is beneficial to the reactions between calcium and vanadium, which was validated by simulated reactions between pure calcium carbonate and vanadium pentoxide. These calcium vanadates are all water insoluble but acid soluble and this causes the low WLRV and relatively high ALRV. After calcium removal by HCl, the WLRV is highly enhanced and reaches about 50%when only 2%NaCl was added. If the HCl content is too high, the stone coal is easily sintered and the formed glass structure can enwrap vanadium, which leads the WLRV to decline. Single water leaching process is not appropriate to extract vanadium from high calcium type stone coal.

  4. Porous polymer film calcium ion chemical sensor and method of using the same

    Science.gov (United States)

    Porter, M.D.; Chau, L.K.

    1991-02-12

    A method of measuring calcium ions is disclosed wherein a calcium sensitive reagent, calcichrome, is immobilized on a porous polymer film. The reaction of the calcium sensitive reagent to the Ca(II) is then measured and concentration determined as a function of the reaction. 1 figure.

  5. Calcium and Vitamin D

    Science.gov (United States)

    ... Home › Patients › Treatment › Calcium/Vitamin D Calcium/Vitamin D Getting enough calcium and vitamin D is essential ... counter medications and calcium supplements. What is Vitamin D and What Does it Do? Vitamin D plays ...

  6. Modeling and analysis of calcium bromide hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Lottes, Steven A.; Lyczkowski, Robert W.; Panchal, Chandrakant B.; Doctor, Richard D. [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)

    2009-05-15

    The main focus of this paper is the modeling, simulation, and analysis of the calcium bromide hydrolysis reactor stage in the calcium-bromine thermochemical water-splitting cycle for nuclear hydrogen production. One reactor concept is to use a spray of calcium bromide into steam, in which the heat of fusion supplies the heat of reaction. Droplet models were built up in a series of steps incorporating various physical phenomena, including droplet flow, heat transfer, phase change, and reaction, separately. Given the large heat reservoir contained in a pool of molten calcium bromide that allows bubbles to rise easily, using a bubble column reactor for the hydrolysis appears to be a feasible and promising alternative to the spray reactor concept. The two limiting cases of bubble geometry, spherical and spherical-cap, are considered in the modeling. Results for both droplet and bubble modeling with COMSOL MULTIPHYSICS trademark are presented, with recommendations for the path forward. (author)

  7. Importance of Calcium

    OpenAIRE

    TANDOĞAN, Berivan; ULUSU, N. Nuray

    2005-01-01

    Calcium is the most abundant mineral in the body. Calcium regulates many cellular processes and has important structural roles in living organisms. Skeletal muscle structure and function, polymerisation of fibrin and the conduction of impulses in the nervous system are regulated by calcium. Calcium is an important intracellular messenger in protozoa, plants, and animals. Calcium-transporting systems which are located in the plasma membrane and in the organelles, regulate the ionic concentrati...

  8. Desorptions- und Reaktionskinetik der Erdalkalien Calcium und Strontium mit Chlor an Wolfram. Part II: Kinetics of the Elementary Steps of the Surface Reaction M + Cl MCl (M = Ca, Sr)

    Science.gov (United States)

    Biedermann, B.; Wassmuth, H. W.

    Mit Hilfe gepulster Atom-bzw. Molekularstrahlen wurde die Desorptionskinetik von Strontium, Calcium und Chlor sowie die Desorptionskinetik der sich auf einer heißen Wolframoberfläche bildenden SrCl-und CaCl- Moleküle untersucht. Als Aktivierungsenergien zur Desorption erhielten wir: = (3,76 +/- 0,05) eV, =(3,32 +/- 0,07) eV, =(4,16 +/- 0,05) eV sowie =(4,2 +/- 0,3) eV und =(3,9 +/- 0, 3)eV.In Kombination mit den im stationären Zustand erhaltenen Ergebnissen aus Teil I [1] läßt sich damit ein Einblick in die Kinetik der Reaktion M + Cl = MCl auf der wolframoberfläche gewinnen und die Temperaturabhängigkeit der Ratenkonstanten der Dissoziation und der Rekombination bestimmen. FuUr die Dissoziationsenergie DSMCl von SrCl bzw. CaCl an der Wolfram-Oberfläche erhielten wir (0,5 +/- 0,5) eV bzw. (0,3 +/- 0,5) eV; die MCl-Moleküle sind an der Oberfläche also praktisch nur durch die Aktivierungsschwelle zur Dissoziation SMCl stabilisiert, die wir für SrCl zu (2,8 +/- 0,5) eV und für CaCl zu (2,3 +/- 0,5) eV bestimmten.Translated AbstractDesorption- and Reactionkinetics of the Alkaline Earth Elements Calcium and Strontium with Chlorine on a Tungsten Surface - Part II: Kinetics of the Elementary Steps of the Surface Reaction M + Cl MCl (M = Ca, Sr)Utilizing pulsed molecular-beam-technique the kinetics of desorption of Strontium, Calcium, and Chlorine as well as that of the molecules SrCl and CaCl, which are formed at the hot tungsten surface, was investigated. Thereby, the following values were obtained for the activation energies of desorption: = (3.76 +/- 0.05) eV, = (3.32 +/- 0.07) eV, = (4.16 +/- 0.05) eV, = (4.2 +/- 0.3) eV and = (3.9 +/- 0.3) eV.Combining these results with the steady-state-results from part I [1] the temperature dependency of the rate constants of dissociation and recombination of MCl-molecules at the tungsten surface could be determined. The values obtained for the dissociation energies D of SrCl and CaCl on tungsten are (0.5 +/- 0.5) e

  9. Drying dichloromethane over calcium hydride

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Lucas Kinard, Kurtis Kasper & Antonios Mikos ### Abstract This protocol describes the drying of dichloromethane by a simple 10 step procedure. One can implement this protocol using common lab glass and lab equipment. First, dichloromethane is refluxed with calcium hydride to remove water. Then, dichloromethane is distilled to separate it from the byproducts of the reflux reaction. This procedure can be implemented in 1 day. ### Introduction In many instances i...

  10. Calcium signaling in physiology and pathophysiology

    Institute of Scientific and Technical Information of China (English)

    He-ping CHENG; Sheng WEI; Li-ping WEI; Alexei VERKHRATSKY

    2006-01-01

    Calcium ions are the most ubiquitous and pluripotent cellular signaling molecules that control a wide variety of cellular processes.The calcium signaling system is represented by a relatively limited number of highly conserved transporters and channels,which execute Ca2+ movements across biological membranes and by many thousands of Ca2+-sensitive effectors.Molecular cascades,responsible for the generation of calcium signals,are tightly controlled by Ca2+ ions themselves and by genetic factors,which tune the expression of different Ca2+-handling molecules according to adaptational requirements.Ca2+ ions determine normal physiological reactions and the development of many pathological processes.

  11. Barium calcium hydroxyapatite solid solutions

    International Nuclear Information System (INIS)

    The replacement of calcium by barium in the hydroxyapatite structure by solid-state reaction at different temperatures and by precipitation from an aqueous system has been investigated by X-ray diffraction and i.r. absorption analyses. The products obtained by solid-state reaction at 1200 deg C are solid solutions over the range of barium concentration 60 to 100 atom %. The lattice dimensions and the i.r. frequencies of the solid solutions vary linearly with the atom % of barium. Only small amounts of barium can be incorporated in hydroxyapatite by precipitation from the aqueous system. (author)

  12. Induction of Sperm Acrosome Reaction wti h Calcium Ionophore A23187 in Wapiti (Cervus elaphus)%钙离子载体诱发马鹿精子顶体反应效果1)

    Institute of Scientific and Technical Information of China (English)

    李和平; 邹琦; 商兰; 刘伟石

    2014-01-01

    Wapiti (Cervus elaphus) sperm was capacitated in vitro by swimming-up and the acrosome reaction (AR) was in-duced by Calcium ionophore A23187 to choose an optimal A23187 system during AR.A23187 of 0.01-100 μmol/L can enhance the ratio of AR on the capacitated sperm and 0.1μmol/L A23187 can obtain the highest ratio of AR (74.00%± 2.62%) for 5-min treatment time.AR of capacitated sperm can, but the uncapacitated sperm cannot, be induced by A23187 in wapiti.%以马鹿( Cervus elaphus)为试验动物,采用上浮法诱导马鹿精子体外获能,以钙离子载体( A23187)诱导马鹿精子顶体反应,进而摸索钙离子载体( A23187)诱发其顶体反应的适宜体系。结果表明:0.01~100.00μmol/L的A23187可提高获能马鹿精子的顶体反应率;其中适宜的A23187浓度为0.10μmol/L,反应的时间为5 min,顶体反应率为(74.00±2.62)%。 A23187能促进获能马鹿精子的顶体反应,但不能显著(P>0.05)促进未获能马鹿精子的顶体反应。

  13. Effect of Strength Enhancement of Soil Treated with Environment-Friendly Calcium Carbonate Powder

    OpenAIRE

    Kyungho Park; Sangju Jun; Daehyeon Kim

    2014-01-01

    This study aims to investigate the effects of the strength improvement of soft ground (sand) by producing calcium carbonate powder through microbial reactions. To analyze the cementation effect of calcium carbonate produced through microbial reaction for different weight ratios, four different types of specimens (untreated, calcium carbonate, cement, and calcium carbonate + cement) with different weight ratios (2%, 4%, 6%, and 8%) were produced and cured for a period of 3 days, 7 days, 14 day...

  14. Curing Reaction Kinetic of Epoxy Resin/Montmorillonite Nanocomposites%4,4’-二氨基二苯砜固化环氧树脂/蒙脱土纳米复合材料反应动力学的研究

    Institute of Scientific and Technical Information of China (English)

    崔继文; 王书红; 高洪福; 张瑞仁; 白术杰; 武冬梅

    2012-01-01

    选择4,4’-二氨基二苯砜(DDS)作为固化剂,采用非等温DSC法研究了双酚A缩水甘油醚型环氧树脂(E-51)/有机蒙脱土(MMT)纳米复合材料的固化反应动力学,根据Kissinger方程计算出该反应的表观活化能(ΔE)为59.91 kJ/mol,基于Crane方程计算得到该反应的反应级数为0.89,表明该反应为一复杂反应,根据固化反应动力学测试结果确定了E-51/DDS/MMT体系固化成型工艺.%4,4'- Diamino - diphenyl - sulfone (DDS) was chosen as curing agent. The curing reaction kinetic of eoxy resin of the diglycidyl ether of bisphenol A (E - 51 )/organic montmorillonite (MMT) system ( E -51/DDS) was studied by non -isothermal DSC and carefully analyzed. Based on the Kissinger method, the apparent activation energy (AE) was 59.91kJ/mol. The reaction order ( n =0.89) was calculated according to Crane theory, which indicates this curing reaction is a complex reaction. Based on this, the technology of curing reaction was determined.

  15. Calcium in diet

    Science.gov (United States)

    ... best source. Milk and dairy products such as yogurt, cheeses, and buttermilk contain a form of calcium ... the amount of calcium in a dairy product. Yogurt, most cheeses, and buttermilk are excellent sources of ...

  16. Fenoprofen calcium overdose

    Science.gov (United States)

    Fenoprofen calcium is a type of medicine called a nonsteroidal anti-inflammatory drug. It is a prescription pain medicine used to relieve symptoms of arthritis . Fenoprofen calcium overdose occurs when someone takes more than the ...

  17. Calcium channel blocker overdose

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium channel blockers are a type of medicine used ...

  18. Fenoprofen calcium overdose

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002649.htm Fenoprofen calcium overdose To use the sharing features on this page, please enable JavaScript. Fenoprofen calcium is a type of medicine called a nonsteroidal ...

  19. Calcium and magnesium disorders.

    Science.gov (United States)

    Goff, Jesse P

    2014-07-01

    Hypocalcemia is a clinical disorder that can be life threatening to the cow (milk fever) and predisposes the animal to various other metabolic and infectious disorders. Calcium homeostasis is mediated primarily by parathyroid hormone, which stimulates bone calcium resorption and renal calcium reabsorption. Parathyroid hormone stimulates the production of 1,25-dihydroxyvitamin D to enhance diet calcium absorption. High dietary cation-anion difference interferes with tissue sensitivity to parathyroid hormone. Hypomagnesemia reduces tissue response to parathyroid hormone. PMID:24980727

  20. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  1. Calcium en cardioplegie

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Meijler, F.L.

    1985-01-01

    Coronary perfusion with a calcium-free solution, followed by reperfusion with a calcium containing solution, may result in acute myocardial cell death and in irreversible loss of the e1ectrical and mechanical activity of the heart. This phenomenon is known as the calcium paradox. A number of cardiop

  2. Calcium ferrite formation from the thermolysis of calcium tris (maleato) ferrate(III)

    Indian Academy of Sciences (India)

    B S Randhawa; Kamaljeet Sweety

    2000-08-01

    For preparing calcium ferrite, calcium tris (maleato) ferrate(III) precursor was prepared by mixing aqueous solutions of iron(III) maleate, calcium maleate and maleic acid. Various physico-chemical techniques i.e. TG, DTG, DTA, Mössbauer, XRD, IR etc have been used to study the decomposition behaviour from ambient to 900°C and ferrite formation. Three consecutive decomposition steps leading to the formation of -Fe2O3 and calcium carbonate have been observed at various stages of thermolysis. In the final stage the ferrite, Ca2Fe2O5, is obtained as a result of solid state reaction between -Fe2O3 and calcium carbonate at 788°C, a temperature much lower than for ceramic method. The results have been compared with those of the oxalate precursor.

  3. KINETIC STUDY OF THE REACTION BETWEEN HYDROXYL-TERMINATED POLYBUTADIENE AND LIQUEFACTION MODIFIED 4,4'-METHYLENEBIS(PHENYL ISOCYANATE) BY FT-IR SPECTROSCOPY%HTPB/液化改性MDI聚合反应的动力学

    Institute of Scientific and Technical Information of China (English)

    曹琪; 刘朋生

    2004-01-01

    用红外分光光度计研究了端羟基聚丁二烯(HTPB)与液化改性4,4'-二苯基甲烷二异氰酸酯(LMDI)的反应动力学,计算了相应体系的反应活化能.通过红外光谱研究了60 ℃时HTPB与LMDI本体聚合反应形成聚氨酯的浓度-时间依赖行为,研究发现,随时间的增加,反应物的浓度呈指数下降,而浓度的倒数-时间则呈直线的关系.结果表明,NCO与OH的反应遵循二级反应动力学,反应活化能Ea=54.3 kJ/mol.

  4. Calcium and calcium isotope changes during carbon cycle perturbations at the end-Permian

    Science.gov (United States)

    Komar, N.; Zeebe, R. E.

    2016-01-01

    Negative carbon and calcium isotope excursions, as well as climate shifts, took place during the most severe mass extinction event in Earth's history, the end-Permian (˜252 Ma). Investigating the connection between carbon and calcium cycles during transient carbon cycle perturbation events, such as the end-Permian, may help resolve the intricacies between the coupled calcium-carbon cycles, as well as provide a tool for constraining the causes of mass extinction. Here we identify the deficiencies of a simplified calcium model employed in several previous studies, and we demonstrate the importance of a fully coupled carbon cycle model when investigating the dynamics of carbon and calcium cycling. Simulations with a modified version of the Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir model, which includes a fully coupled carbon-calcium cycle, indicate that increased weathering rates and ocean acidification (potentially caused by Siberian Trap volcanism) are not capable of producing trends observed in the record, as previously claimed. Our model results suggest that combined effects of carbon input via Siberian Trap volcanism (12,000 Pg C), the cessation of biological carbon export, and variable calcium isotope fractionation (due to a change in the seawater carbonate ion concentration) represents a more plausible scenario. This scenario successfully reconciles δ13C and δ44Ca trends observed in the sediment record, as well as the proposed warming of >6°C.

  5. Calcium and calcium isotope changes during carbon cycle perturbations at the end-Permian

    Science.gov (United States)

    Komar, Nemanja; Zeebe, Richard

    2016-04-01

    Negative carbon and calcium isotope excursions, as well as climate shifts, took place during the most severe mass extinction event in Earth's history, the end-Permian (˜252 Ma). Investigating the connection between carbon and calcium cycles during transient carbon cycle perturbation events, such as the end-Permian, may help resolve the intricacies between the coupled calcium-carbon cycles, as well as provide a tool for constraining the causes of mass extinction. Here, we identify the deficiencies of a simplified calcium model employed in several previous studies and we demonstrate the importance of a fully coupled carbon-cycle model when investigating the dynamics of carbon and calcium cycling. Simulations with a modified version of the LOSCAR model, which includes a fully coupled carbon-calcium cycle, indicate that increased weathering rates and ocean acidification (potentially caused by Siberian Trap volcanism) are not capable of producing trends observed in the record, as previously claimed. Our model results suggest that combined effects of carbon input via Siberian Trap volcanism (12,000 Pg C), the cessation of biological carbon export, and variable calcium isotope fractionation (due to a change in the seawater carbonate ion concentration) represents a more plausible scenario. This scenario successfully reconciles δ13C and δ44Ca trends observed in the sediment record, as well as the proposed warming of >6oC.

  6. Cyclotron production of 44Sc: From bench to bedside

    International Nuclear Information System (INIS)

    Introduction: 44Sc, a PET radionuclide, has promising decay characteristics (T1/2 = 3.97 h, Eβ+av = 632 keV) for nuclear imaging and is an attractive alternative to the short-lived 68Ga (T1/2 = 68 min, Eβ+av = 830 keV). The aim of this study was the optimization of the 44Sc production process at an accelerator, allowing its use for preclinical and clinical PET imaging. Methods: 44CaCO3 targets were prepared and irradiated with protons (~ 11 MeV) at a beam current of 50 μA for 90 min. 44Sc was separated from its target material using DGA extraction resin and concentrated using SCX cation exchange resin. Radiolabeling experiments at activities up to 500 MBq and stability tests were performed with DOTANOC by investigating different scavengers, including gentisic acid. Dynamic PET of an AR42J tumor-bearing mouse was performed after injection of 44Sc-DOTANOC. Results: The optimized chemical separation method yielded up to 2 GBq 44Sc of high radionuclidic purity. In the presence of gentisic acid, radiolabeling of 44Sc with DOTANOC was achieved with a radiochemical yield of ~ 99% at high specific activity (10 MBq/nmol) and quantities which would allow clinical application. The dynamic PET images visualized increasing uptake of 44Sc-DOTANOC into AR42J tumors and excretion of radioactivity through the kidneys of the investigated mouse. Conclusions: The concept “from-bench-to-bedside” was clearly demonstrated in this extended study using cyclotron-produced 44Sc. Sufficiently high activities of 44Sc of excellent radionuclidic purity are obtainable for clinical application, by irradiation of enriched calcium at a cyclotron. This work demonstrates a promising basis for introducing 44Sc to clinical routine of nuclear imaging using PET

  7. Association between calcium ionophore A23187 induced acrosome reaction rate, total acrosin activity and semen analysis, the outcome of in vitro fertilization%钙离子载体A23187诱发的精子顶体反应率、顶体酶总活性与精液参数及体外受精结局的关系研究

    Institute of Scientific and Technical Information of China (English)

    郭小桥; 余波澜; 周华; 司沙沙; 曹定娅; 刘见桥; 孙筱放

    2013-01-01

    Objective To investigate the association between the calcium ionophore A23187 induced sperm acrosome reaction rate, total acrosin activity and semen parameters and the IVF outcome, and to compare the predictive value for the male fertility and the outcome of IVF between calcium ionophore A23187 induced sperm acrosome reaction rate and sperm total acrosoin activity. Methods Sperm acrosome reaction was induced by calcium ionophore A23187,while sperm acrosin activity was determined by the modified Kennedy method. In this study, 150 cycles of IVF-ET were included, which were divided into Normal semen Group (85 cycles), Teratospermia Group (44 cycles), Asthenozoospermia Group (6 cycles). Compare the association between the calcium ionophore A23187 induced sperm acrosome reaction rate, total acrosin activity and normal morphology sperm percentage, concentration, activity in the 150 cycles and subgroups. Analyze the difference of the sperm acrosome reaction rate and total acrosin activity in Pregnancy Group and Non-pregnancy Group. Use the Receiver Operating Characteristic curve to make out the threshold of the sperm acrosome reaction rate and total acrosin activity for predicting the IVF pregnancy outcomes. Results In this 150 samples, there are no statistically significant differences between sperm acrosome reaction rate and sperm concentration, progressive velocity rate, the percentage of normal sperm morphology, fertility rate, and their related coefficient are respectively as follow:0.120, 0.018, 0.084, 0.054(P>0.05). But the negative correlation is statistically significant different between sperm acrosome reaction rate and teratozoospermia index(r=-0.183, P=0.025). There are significant correlations between sperm acrosin activity and sperm concentration(r=0.172, P0.05) and fertility rate(r=0.039, P>0.05). There are no statistically significant differences between sperm acrosome rate and fertility rate in Normal semen Group(r=-0.039, P>0.05), Teratospermia Group

  8. Calcium binding to low molecular weight compounds and health promoting products

    DEFF Research Database (Denmark)

    Vavrusova, Martina

    absorption. Therefore, calcium as an essential nutrient should not be underestimated in our diet. Milk and dairy products are good sources of bioavailable calcium due to specific protein binding. Other sources of calcium, apart from a balanced and healthy diet, are calcium supplements and calcium fortified...... food. Therefore, an understanding of the basic chemistry of calcium binding to low molecular weight compounds can contribute to a general knowledge about calcium bioavailability and also to product improvement. Calcium precipitation with palmitate was described by a first-order reaction for conditions...... calcium Dgluconate only slowly precipitated after a lag phase. On the other hand, the slow dissolution of calcium D-gluconate by sodium L-lactate in aqueous solution with the reverse lactate/gluconate ratio did not result in a similar solution since fast precipitation prevented formation of a homogenous...

  9. Catalytic oxidation of calcium sulfite in solution/aqueous slurry

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-qin; WU Zhong-biao; WANG Da-hui

    2004-01-01

    Forced oxidation of calcium sulfite aqueous slurry is a key step for the calcium-based flue gas desulfurization(FGD) residue. Experiments were conducted in a semi-batch system and a continuous flow system on lab scales. The main reactor in semi-batch system is a 1000 ml volume flask. It has five necks for continuous feeding of gas and a batch of calcium sulfite solution/aqueous slurry. In continuous flow system, the main part is a jacketed Pyrex glass reactor in which gas and solution/aqueous slurry are fed continuously. Calcium sulfite oxidation is a series of complex free-radical reactions. According to experimental results and literature data, the reactions are influenced significantly by manganese as catalyst. At low concentration of manganese and calcium sulfite, the reaction rate is dependent on 1.5 order of sulfite concentration, 0.5 order of manganese concentration, and zero order of oxygen concentration in which the oxidation is controlled by chemical kinetics. With concentrations of calcium sulfite and manganese increasing, the reactions are independent gradually on the constituents in solution but are impacted by oxygen concentration. Manganese can accelerate the free-radical reactions, and then enhances the mass transfer of oxygen from gas to liquid. The critical concentration of calcium sulfite is 0.007 mol/L, manganese is 10-4 mol/L, and oxygen is of 0.2-0.4 atm.

  10. Synthesis of Calcium Silicate (Casio3 Using Calcium Fluoride, Quartz and Microbes

    Directory of Open Access Journals (Sweden)

    B. Gopal Krishna

    2015-09-01

    Full Text Available Microbes like bacteria, algae, fungi and virus play an important role to catalyst chemical reactions. In Nature, ores or minerals of different compounds are formed due to microbial environment and other factors like weathering. Microbial environment is also instrumental in forming calcium containing silicate minerals. Chemical reactions occur under microbial environment because microbes have the ability to control or modify different factors like pH, chemical potential and temperature during reactions. In this paper, synthesis of calcium silicate (CaSiO3 using calcium fluoride (CaF2 and quartz (SiO2 under microbial environment in a laboratory is being adopted to produce the required material. XRD technique is used to confirm the formation of CaSiO3.

  11. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  12. EXERCISE ENHANCING CALCIUM ABSORPTION MECHANISM

    OpenAIRE

    Muliani

    2013-01-01

    Calcium has important role in many biological processes therefore calcium homeostasis should be maintained. Imbalance in calcium homeostasis would affects the bone metabolism, neuromuscular function, blood coagulation, cell proliferation and signal transduction. Homeostasis of calcium is maintained by three major organs: gastrointestinal tract, bone and kidney. Intestinal calcium absorption is the sole mechanism to supply calcium to the body. Calcium absorption controlled by calcitropic hormo...

  13. Antagonist effects of calcium on borosilicate glass alteration

    Energy Technology Data Exchange (ETDEWEB)

    Mercado-Depierre, S. [CEA Marcoule, DTCD SPDE LCLT, 30207 Bagnols sur Cèze (France); Angeli, F., E-mail: frederic.angeli@cea.fr [CEA Marcoule, DTCD SPDE LCLT, 30207 Bagnols sur Cèze (France); Frizon, F. [CEA Marcoule, DTCD SECM LP2C, 30207 Bagnols sur Cèze (France); Gin, S. [CEA Marcoule, DTCD SPDE LCLT, 30207 Bagnols sur Cèze (France)

    2013-10-15

    Graphical abstract: Display Omitted -- Highlights: •Kinetic study of glass alteration is investigated in calcium-enriched solutions. •New insights into silicon–calcium interactions in glass/cement systems are proposed. •Glass alteration is controlled by pH, Ca concentration and reaction progress. •Evidence of antagonist effects according to the importance of these parameters. -- Abstract: Numerous studies have been conducted on glass and cement durability in contact with water, but very little work to date has focused directly on interactions between the two materials. These interactions are mostly controlled by silicon–calcium reactivity. However, the physical and chemical processes involved remain insufficiently understood to predict the evolution of coupled glass–cement systems used in several industrial applications. Results are reported from borosilicate glass alteration in calcium-rich solutions. Our data show that four distinct behaviors can be expected according to the relative importance of three key parameters: the pH, the reaction progress (short- or long-term alteration) and the calcium concentration. Glass alteration is thus controlled by specific mechanisms depending on the solution chemistry: calcium complexation at the glass surface, precipitation of calcium silicate hydrates (C–S–H) or calcium incorporation in the altered layer. These findings highlight the impact of silicon–calcium interactions on glass durability and open the way for a better understanding of glass–cement mixing in civil engineering applications as well as in nuclear waste storage.

  14. Dengue and Calcium

    OpenAIRE

    Shivanthan, Mitrakrishnan C; Rajapakse, Senaka

    2014-01-01

    Dengue is potentially fatal unless managed appropriately. No specific treatment is available and the mainstay of treatment is fluid management with careful monitoring, organ support, and correction of metabolic derangement. Evidence with regards to the role of calcium homeostasis in dengue is limited. Low blood calcium levels have been demonstrated in dengue infection and hypocalcemia maybe more pronounced in more severe forms. The cause of hypocalcemia is likely to be multifactorial. Calcium...

  15. Measurements of intracellular calcium

    International Nuclear Information System (INIS)

    Intracellular calcium concentration ([Ca2+]i) has been measured in cultured cells by using Fura-2 load cells and a computer-controlled Perkin Elmer LS-5B spectrofluorometer. Increased [Ca2+]i in cells exposed to extracellular bilirubin was observed both with and without extracellular calcium. However, the increase was considerable larger with extracellular calcium. The enhancement of [Ca2+]i became smaller with decreasing bilirubin/BSA (bovine serum albumine) ratio. 5 refs., 5 figs

  16. Discussion on the mechanism of the calcium absorption in the human body

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The present article discusses a new mechanism of calcium absorption in the human body. The mechanism is revealed as follows. First, after food is digested in the stomach, calcium ions (Ca2+) are released. The small intestine secretes amino acid or short peptide chain with small molecniar weight automatically, which are called chelating agent; when the calcium ions from the stomach get to the small intestine, the reaction of the chelating agent with the calcium ions occurs, producing the neutral amino acid calcium chelate. Then, this kind of calcium chelate with small molecular weight is absorbed as a whole into the tissues of the small intestine. After being absorbed, in the cell the calcium chelate can break down its chelating bond automatically and decompose into the amino acid and calcium ion again. Finally, the calcium ion goes into blood through portal vein and is transferred to the organs and also deposits on the bone. The reason for the body's calcium insufficiency, which has no linear relation with the calcium intake amount, is the lack of the amino acid secreted by the small intestine. The main barrier that influences the calcium absorption is anion pollution. The calcium absorptivity of the body has nothing to do with the solubility of the calcium source out of the body.A new kind of calcium supplement agent--glycine calcium chelate--is synthesized, whose molecular weight is 206.06(containing a molecular water). If the glycine calcium chelate is used to make calcium supplement agent, about 20 mg calcium element (converted from the glycine calcium chelate,the same below, no longer indicated) per day for one person,50 mg at most, is enough to maintain the positive balance of calcium metabolism.``

  17. New optically active poly(amide-imide)s derived from N,N'-(4,4-diphthaloyl)-bis-L-leucine and hydantoin derivatives: Synthesis and properties

    Institute of Scientific and Technical Information of China (English)

    Khalil Faghihi

    2009-01-01

    Six new optically active poly(amide-imide)s (5a-f) were synthesized through the direct polycondensation reaction of N,N'-(4,4'-diphthaloyl)-bis-L-leucine (3) with six hydantoin derivatives (4a-f). Triphenyl phosphlte (TPP)/pyridine in the presence of calcium chloride (CaCl_2) and N-methyl-2-pyrrolidone (NMP) were successfully applied for direct polycondensation. The polycondensation reactions produce a series of new poly(amide-imide)s (Sa-f) in high yields, and inherent viscosity between 0.42 and 0.55 dL/g. The resulting poly(amide-imide)s (Sa-f) were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA and DTG), solubility test and FT-IR spectroscopy.

  18. Expression of CD44 in Cultured Human Trabecular Meshwork Cells

    Institute of Scientific and Technical Information of China (English)

    Zhongguo Li; Hong Zhang

    2004-01-01

    Purpose:To determine whether cultured human trabecular meshwork cells express CD44 and to discuss their possible relationship with primary open angle glaucoma.Methods:Human trabecular meshwork cells were cultured in DMEM/F12 media. Total RNAs from the cells were extracted with Trizol reagent. Messenger RNA expression of CD44 in human trabecular meshwork cells was examined by using reverse transcriptasepolymerase chain reaction ( RT-PCR ) analysis. Expression of CD44 was confirmed by Western-blotting and immunofiuorescent microscopy. Effect of CD44-specific antisense oligonucleotide on adhesion of trabecular meshwork cells to hyaluronate was determined by MTT assay.Results:A single RT-PCR product whose size was 471bp was obtained.A band about 80kD was stained by Western-blot. Immunofiuorescent examination of expression of CD44 on the cell surface was positive and reactions were mainly localized in cell membranes.Adhesion of trabecular meshwork cells to hyaluronate was inhibited by CD44-specific antisense oligonucleotide.Conclusions: Cultured human trabecular meshwork cells express CD44. CD44 may play a role in pathogenesis of primary open angle glaucoma. Eye Science 2004;20:52-56.

  19. Finite Volume Model to Study Calcium Diffusion in Neuron Involving JRYR, JSERCA and JLEAK

    OpenAIRE

    tripathi, Amrita; Adlakha, Neeru

    2013-01-01

    Calcium dynamics is the highly responsible for intracellular electrical (action potential) and chemical (neurotransmitter) signaling in neuron cell. The Mathematical modeling of calcium dynamics in neurons lead to the reaction diffusion equation which involves the parameters like diffusion coefficient, free calcium, bound calcium, buffers and bound buffer. Here the parameters like receptors, serca and leak are also incorporated in the model. Appropriate boundary conditions have been framed ba...

  20. Effect of inhibitors on macroscopical oxidation kinetics of calcium sulfite

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yi; WANG Li-dong; WANG Xiao-ming; LI Qiang-wei; XU Pei-yao

    2005-01-01

    In the presence of inhibitors, the macroscopical oxidation kinetics of calcium sulfite, the main byproduct in wet limestone scrubbing, was studied for the first time by adding different inhibitors and varying pH, concentration of calcium sulfite, oxygen partial pressure, concentration of inhibitors and temperature. The mathematical model about the general oxidation reaction was established,which was controlled by three steps involving dissolution of calcium sulfite, mass transfer of oxygen and chemical reaction in the solution.It was concluded that the general reaction was controlled by mass transfer of oxygen under uncatalyzed conditions, while it was controlled by dissolution of calcium sulfite after adding three kinds of inhibitors. Thus, the theory was provided for investigating the mechanism and oxidation kinetics of sulfite. The beneficial references were also supplied for design of oxidation technics in the wet limestone scrubbing.

  1. Calcium D-saccharate

    DEFF Research Database (Denmark)

    Garcia, André Castilho; Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt

    2016-01-01

    Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc......° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1...... K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d...

  2. Serum Calcium Level in Hypertension

    OpenAIRE

    Hazari, Mohammed Abdul Hannan; Arifuddin, Mehnaaz Sameera; Muzzakar, Syed; Reddy, Vontela Devender

    2012-01-01

    Background: The alterations in extracellular calcium level may influence intracellular calcium level and possibly play a role in the pathogenesis of essential hypertension. Aim: The purpose was to find out the association between serum calcium levels and hypertension; and to compare the serum calcium levels between normotensive controls, hypertensive subjects on calcium channel blockers, and hypertensive subjects on antihypertensive medication other than calcium channel blockers. Materials an...

  3. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free calciu

  4. Synthesis of Calcium Silicate (Casio3) Using Calcium Fluoride, Quartz and Microbes

    OpenAIRE

    B. Gopal Krishna; M. Jagannadha Rao

    2015-01-01

    Microbes like bacteria, algae, fungi and virus play an important role to catalyst chemical reactions. In Nature, ores or minerals of different compounds are formed due to microbial environment and other factors like weathering. Microbial environment is also instrumental in forming calcium containing silicate minerals. Chemical reactions occur under microbial environment because microbes have the ability to control or modify different factors like pH, chemical potential and tempera...

  5. Direct chemical reduction of neptunium oxide to neptunium metal using calcium and calcium chloride

    Science.gov (United States)

    Squires, Leah N.; Lessing, Paul

    2016-04-01

    A process of direct reduction of neptunium oxide to neptunium metal using calcium metal as the reducing agent is discussed. After reduction of the oxide to metal, the metal is separated by density from the other components of the reaction mixture and can be easily removed upon cooling. The direct reduction technique consistently produces high purity (98%-99% pure) neptunium metal.

  6. Behavior of calcium silicate hydrate in aluminate solution

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-bin; ZHAO Zhuo; LIU Gui-hua; ZHOU Qiu-sheng; PENG Zhi-hong

    2005-01-01

    Using calcium hydroxide and sodium silicate as starting materials, two kinds of calcium silicate hydrates, CaO · SiO2 · H2O and 2CaO · SiO2 · 1.17H2O, were hydro-thermally synthesized at 120 ℃. The reaction rule of calcium silicate hydrate in aluminate solution was investigated. The result shows that CaO · SiO2 · H2O is more stable than 2CaO · SiO2 · 1.17H2 O in aluminate solution and its stability increases with the increase of reaction temperature but decreases with the increase of caustic concentration. The reaction between calcium silicate hydrate and aluminate solution is mainly through two routes. In the first case, Al replaces partial Si in calcium silicate hydrate, meanwhile 3CaO · Al2 O3 · xSiO2 · (6-2x) H2 O (hydro-garnet) is formed and some SiO2 enters the solution. In the second case, calcium silicate hydrate can react directly with aluminate solution, forming hydro-garnet and Na2O · Al2O3 · 2SiO2 · nH2O (DSP). The desilication reaction of aluminate solution containing silicate could contribute partially to forming DSP.

  7. Neuronal calcium sparks and intracellular calcium “noise”

    OpenAIRE

    Melamed-Book, Naomi; Kachalsky, Sylvia G.; Kaiserman, Igor; Rahamimoff, Rami

    1999-01-01

    Intracellular calcium ions are involved in many forms of cellular function. To accommodate so many control functions, a complex spatiotemporal organization of calcium signaling has developed. In both excitable and nonexcitable cells, calcium signaling was found to fluctuate. Sudden localized increases in the intracellular calcium concentration—or calcium sparks—were found in heart, striated and smooth muscle, Xenopus Laevis oocytes, and HeLa and P12 cells. In the nervous system, intracellular...

  8. Playing with Opening and Closing of Heterocycles: Using the Cusmano-Ruccia Reaction to Develop a Novel Class of Oxadiazolothiazinones, Active as Calcium Channel Modulators and P-Glycoprotein Inhibitors

    Directory of Open Access Journals (Sweden)

    Domenico Spinelli

    2014-10-01

    Full Text Available As a result of the ring-into-ring conversion of nitrosoimidazole derivatives, we obtained a molecular scaffold that, when properly decorated, is able to decrease inotropy by blocking L-type calcium channels. Previously, we used this scaffold to develop a quantitative structure-activity relationship (QSAR model, and we used the most potent oxadiazolothiazinone as a template for ligand-based virtual screening. Here, we enlarge the diversity of chemical decorations, present the synthesis and in vitro data for 11 new derivatives, and develop a new 3D-QSAR model with recent in silico techniques. We observed a key role played by the oxadiazolone moiety: given the presence of positively charged calcium ions in the transmembrane channel protein, we hypothesize the formation of a ternary complex between the oxadiazolothiazinone, the Ca2+ ion and the protein. We have supported this hypothesis by means of pharmacophore generation and through the docking of the pharmacophore into a homology model of the protein. We also studied with docking experiments the interaction with a homology model of P-glycoprotein, which is inhibited by this series of molecules, and provided further evidence toward the relevance of this scaffold in biological interactions.

  9. Calcium and magnesium silicate hydrates

    International Nuclear Information System (INIS)

    Deep geological disposals are planed to discard long-lived intermediate-level and high-level radioactive wastes. Clay-based geological barriers are expected to limit the ingress of groundwater and to reduce the mobility of radioelements. In the interaction zone between the cement and the clay based material alteration can occur. Magnesium silicate hydrates (M-S-H) have been observed due to the reaction of magnesium sulfate containing groundwater with cements or in the interaction zone between low-pH type cement and clays. M-S-H samples synthesized in the laboratory showed that M-S-H has a variable composition within 0.7 ≤ Mg/Si ≤ 1.5. TEM/EDS analyses show an homogeneous gel with no defined structure. IR and 29Si NMR data reveal a higher polymerization degree of the silica network in M-S-H compared to calcium silicate hydrates (C-S-H). The presence of mainly Q3 silicate tetrahedrons in M-S-H indicates a sheet like or a triple-chain silica structure while C-S-H is characterised by single chain-structure. The clear difference in the silica structure and the larger ionic radius of Ca2+ (1.1 Angstrom) compared to Mg2+ (0.8 Angstrom) make the formation of an extended solid solution between M-S-H and C-S-H gel improbable. In fact, the analyses of synthetic samples containing both magnesium and calcium in various ratios indicate the formation of separate M-S-H and C-S-H gels with no or very little uptake of magnesium in CS-H or calcium in M-S-H

  10. Synthesis and Evaluation of Environmentally Friendly Calcium Isostearate Detergent with Excellent Oil Solubility

    Institute of Scientific and Technical Information of China (English)

    Wang Yonglei; Li Haiyun; Fang Hongxia; Xu Tao; Lu Lulu

    2016-01-01

    This article describes a method for synthesizing an excellent oil soluble calcium isostearate detergent using isostearic acid and calcium hydroxide as main starting materials. Reaction conditions, including the molar ratios of calcium hydroxide to isostearic acid, methanol to calcium hydroxide and water to calcium hydroxide, the carbonation temperature, the CO2flow rate, and the volume of injected CO2, were optimized. Under the optimized conditions, a high alkalinity calcium isostearate detergent with a total base number (TBN) of 358 mgKOH/g and an overbased calcium isostearate detergent with a value of TBN equating to 406 mgKOH/g could be obtained. Finally, the properties of the calcium isostearate detergent were evaluated by the size distribution analysis, the thermogravimetric analysis (TGA) and the coking tendency tester.

  11. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

    Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

  12. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

    NARCIS (Netherlands)

    Jonge, H.J. de; Gans, R.O.; Huls, G.A.

    2012-01-01

    Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate ab

  13. Preparation of Hollow Calcium Silicate Microparticles by Simple Emulsion

    OpenAIRE

    Eiichi Toorisaka; Syotaro Nagamatsu; Yasunobu Saruwatari; Makoto Hirata; Tadashi Hano

    2014-01-01

    Hollow calcium silicate microparticles were prepared by mixing a water-in-oil (W/O) emulsion containing silicate ions in aqueous phase with an oil phase containing a calcium/di-2-ethylhexyl phosphoric acid (D2EHPA) complex. The inorganic precipitation reaction at the oil-water interface was accelerated by using a simple W/O emulsion. Hollow microparticles were obtained when the mole ratio of D2EHPA and calcium in the oil phase was nearly 2:1. The shell formation of the par-ticles depended on ...

  14. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  15. Magnesium and calcium sulfate stabilities and the water budget of Mars

    Science.gov (United States)

    Chou, I.-Ming; Seal, R.R., II

    2007-01-01

    Magnesium sulfate probably plays a dominant role in the water cycle of Mars away from the polar ice caps through hydration and dehydration reactions. This prominence is due to its abundance, its occurrence in numerous hydration states, and its ability to hydrate and dehydrate rapidly. New experimental studies on the metastable reaction between hexahydrite (MgSO4??6H2O) and starkeyite (MgSO4-4H2O) as a function of temperature and relative humidity, supplemented by recent investigations of the stable reaction between epsomite (MgSO4??7H2O) and hexahydrite and by phase equilibrium calculations, suggest that the most important magnesium sulfate phases involved in the Martian water cycle are MgSO4??11 H2O, epsomite, starkeyite, and possibly kieserite (MgSO4??H2O). Hexahydrite is not predicted to be stable on the surface of Mars. During diurnal variations in temperature and relative humidity, 1 kg of MgSO4 can release or remove from the atmosphere 1.5 kg of H2O by cycling between kieserite and MgSO4??11 H2O. Despite subequal abundances of calcium sulfate, calcium sulfates are not likely to be important in the water cycle of the planet because of sluggish rates of hydration and dehydration and a more limited range of H2O concentrations per kilogram of CaSO4 (0.00 to 0.26 kg kg-1). Modern or recent erosion on Mars attributed to liquid water may be due to the dehydration Of MgSO4??11 H2O because of the inferred abundance and likelihood of occurrence of this phase and its limited stability relative to known variations in temperature and relative humidity.

  16. CALCIUM ISOTOPE COMPOSITION OF METEORITES, EARTH, AND MARS

    International Nuclear Information System (INIS)

    The relative abundances of calcium isotopes in the mass range 40-44 were measured in primitive and differentiated meteorites and igneous rocks from Earth and Mars in search of non-mass-dependent variations that could provide clues about early solar system processes. Most bulk samples of planetary materials have calcium isotopic compositions identical with Earth's within the current resolution of about 0.01% in 40Ca/44Ca. Possible exceptions include carbonaceous chondrites, some ordinary chondrites, and two samples of calcium-aluminum-rich inclusions, which have small excesses of 40Ca. The samples with 40Ca excesses are also known to have 50Ti and 135Ba excesses and 142Nd and 144Sm deficits. Collectively these data from refractory elements suggest that the planetary embryos represented by chondrites preserve isotopic heterogeneity that reflects different nucleosynthetic sources. No late admixture from a single nucleosynthetic source can explain all observations. The results are most compatible with variable proportions of material derived from Type II supernovae. The initial calcium isotope compositions of Earth and Mars are indistinguishable and similar to the 40Ca abundance found in some chondrites and all differentiated meteorites studied. It appears that isotopic heterogeneity in calcium was still present at the completion of disk formation but was homogenized during planetary accretion.

  17. Anti-CD44-mediated blockade of leukocyte migration in skin-associated immune diseases.

    Science.gov (United States)

    Zöller, Margot; Gupta, Pooja; Marhaba, Rachid; Vitacolonna, Mario; Freyschmidt-Paul, Pia

    2007-07-01

    CD44 plays an important role in leukocyte extravasation, which is fortified in autoimmune diseases and delayed-type hypersensitivity (DTH) reactions. There is additional evidence that distinct CD44 isoforms interfere with the extravasation of selective leukocyte subsets. We wanted to explore this question in alopecia areata (AA), a hair-follicle centric autoimmune disease, and in a chronic eczema. The question became of interest because AA is treated efficiently by topical application of a contact sensitizer, such that a mild DTH reaction is maintained persistently. Aiming to support the therapeutic efficacy of a chronic eczema in AA by anti-CD44 treatment, it became essential to control whether a blockade of migration, preferentially of AA effector cells, could be achieved by CD44 isoform-specific antibodies. Anti-panCD44 and anti-CD44 variant 10 isoform (CD44v10) inhibited in vitro migration of leukocytes from untreated and allergen-treated, control and AA mice. In vivo, both antibodies interfered with T cell and monocyte extravasation into the skin; only anti-panCD44 prevented T cell homing into lymph nodes. Contributing factors are disease-dependent alterations in chemokine/chemokine receptor expression and a blockade of CD44 on endothelial cells and leukocytes. It is important that CD44 can associate with several integrins and ICAM-1. Associations depend on CD44 activation and vary with CD44 isoforms and leukocyte subpopulations. CD44 standard isoform preferentially associates with CD49d in T cells and CD44v10 with CD11b in monocytes. Accordingly, anti-panCD44 and anti-CD49d inhibit T cell, anti-CD11b, and anti-CD44v10 macrophage migration most efficiently. Thus, allergen treatment of AA likely can be supported by targeting AA T cells selectively via a panCD44-CD49d-bispecific antibody. PMID:17442857

  18. Thin-target excitation functions, cross-sections and optimised thick-target yields for natMo(p,xn)94g,95m,95g,96(m+g)Tc nuclear reactions induced by protons from threshold up to 44 MeV. No Carrier Added radiochemical separation and quality control

    International Nuclear Information System (INIS)

    This work describes the method adopted in our laboratories, to produce 94gTc, 95gTc, 95mTc and 96gTc radionuclides via proton-cyclotron irradiation on molybdenum targets of natural isotopic composition. A new set of experimental thin-target excitation functions and 'effective' cross-sections for direct natMo(p,xn)ATc [with A=94, 95, 95, 96] nuclear reactions, with incident proton energy in the range from threshold up to 44 MeV is presented. Some definitions of the equations used and nuclear data traceability are reported. Thick-target yield values were calculated and optimised, by numerical fitting and integration of the measured excitation functions. These values allow optimisation of production yield of one radionuclide, minimising at the same time the yield of the others. Radiochemical separation on NCA technetium radionuclides from both molybdenum target and niobium, zirconium and yttrium radioactive by-products is reported. Quality control tests of the radiotracers were developed for the applications envisaged in environmental metallo-biochemical toxicology

  19. Influence of the neutron numbers of projectile and target on the evaporation residue cross sections in hot fusion reactions

    Science.gov (United States)

    Zhu, Long; Su, Jun; Zhang, Feng-Shou

    2016-06-01

    Within the framework of a dinuclear system model, the influence of projectile and target neutron number on capture cross section, fusion probability, and survival probability for the reactions S,3634+238U and 48Ca+Pu 239 ,240 ,242 ,244 are investigated. The calculated excitation functions are in good agreement with the experimental data. To synthesize more unknown neutron-deficient isotopes of already-known superheavy elements, the possibility of using lighter calcium isotopes to induce hot fusion reactions is investigated and the maximal evaporation residual cross sections for Ca 44 ,46 ,48 -induced hot fusion reactions to produce unknown neutron-deficient superheavy nuclei with Z =112 -116 are predicted.

  20. Luminescent Properties of Green Phosphor Ca8Mg(SiO4)4Cl2:Eu2+, Dy3+ for LED Applications

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The new phosphor calcium magnesium chlorosilicate, codoped with Eu2+ and Dy3+, was synthesized with the help of the high temperature solid state reaction in reducing atmosphere. The excitation and emission spectra were very similar to that of Ca8Mg(SiO4)4Cl2:Eu2+, and the Dy3+ concentration influenced the emission intensity of this phosphor. The intensity of Eu2+ and Dy3+ codoped CMSC was stronger than that of Eu2+ singly doped CMSC. The emission spectrum of the Dy3+ ion overlapped the absorption band of the Eu2+ ion, indicating that an energy transfer from Dy3+ to Eu2+ took place in CMSC:Eu2+, Dy3+ phosphor. The mechanism of the energy transfer from Dy3+ to Eu2+, in this phosphor, might be resonant energy transfer.

  1. Weak transition of 44Ca

    International Nuclear Information System (INIS)

    A study of the nuclear core contribution to the excited nuclear states was done, along with its theoretical evaluation and interpretation, in the light nuclei region. The 727 KeV gamma ray transition between the 1885 KeV O+ and 1157 KeV - 2+ states was detected, putting in evidence experimentally, the possibility of the 0+ state, characterized as core excitation, and found to be by + decay or electron capture from44,44mSc. The formation of the 2850 KeV state, due to 880 KeV transition from the 3667 KeV state, is re-discussed. The 564 KeV and 1684 KeV transitions from the 2850 KeV state to the 2285 KeV and 1157 KeV states, respectively, are also discussed. A new scheme is proposed for the 44Ca excited states. (Author)

  2. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    Science.gov (United States)

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

    The gravimetric determination of calcium as calcium carbonate is described. This experiment is suitable for undergraduate quantitative analysis laboratories. It is less expensive than determination of chloride as silver chloride. (BB)

  3. CALCIUM SOAP LUBRICANTS

    OpenAIRE

    Alaz, Izer; Tugce, Nefise; Devrim, Balköse

    2014-01-01

    The article studies the properties of calcium stearate (CaSt2) and lubricants produced on its basis. These lubricants were prepared using sodium stearate and calcium chloride by subsidence from aqueous solutions. The CaSt2 and the light fraction of crude oil were mixed together to obtain lubricating substances. The article shows that CaSt2 had the melting temperature of 142.8 C that is higher than the melting temperature of crude oil (128 C). The compositions of obtained lubricants were stu...

  4. Symmetry violation in nuclear reactions

    International Nuclear Information System (INIS)

    Precision studies of nuclear reactions can be used to search for small violations of the discrete symmetries. Recent and proposed experimental work using nuclear reactions to study the breakdown of three symmetries - isospin (I), parity (P) and time-reversal (T) is reviewed. 44 references

  5. CALCIUM-INDUCED SUPRAMOLECULAR STRUCTURES IN THE CALCIUM CASEINATE SYSTEM

    Science.gov (United States)

    The molecular details deciphering the spontaneous calcium-induced protein aggregation process in the calcium caseinate system remain obscure. Understanding this complex process could lead to potential new applications of this important food ingredient. In this work, we studied calcium-induced supra...

  6. A sensor for calcium uptake

    OpenAIRE

    Collins, Sean; Meyer, Tobias

    2010-01-01

    Mitochondria — the cell’s power plants — increase their energy production in response to calcium signals in the cytoplasm. A regulator of the elusive mitochondrial calcium channel has now been identified.

  7. Children's Bone Health and Calcium

    Science.gov (United States)

    ... Trials Resources and Publications Children's Bone Health and Calcium: Condition Information Skip sharing on social media links ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

  8. Interaction of H2S with Calcium Permeable Channels and Transporters

    Directory of Open Access Journals (Sweden)

    Weihua Zhang

    2015-01-01

    Full Text Available A growing amount of evidence has suggested that hydrogen sulfide (H2S, as a gasotransmitter, is involved in intensive physiological and pathological processes. More and more research groups have found that H2S mediates diverse cellular biological functions related to regulating intracellular calcium concentration. These groups have demonstrated the reciprocal interaction between H2S and calcium ion channels and transporters, such as L-type calcium channels (LTCC, T-type calcium channels (TTCC, sodium/calcium exchangers (NCX, transient receptor potential (TRP channels, β-adrenergic receptors, and N-methyl-D-aspartate receptors (NMDAR in different cells. However, the understanding of the molecular targets and mechanisms is incomplete. Recently, some research groups demonstrated that H2S modulates the activity of calcium ion channels through protein S-sulfhydration and polysulfide reactions. In this review, we elucidate that H2S controls intracellular calcium homeostasis and the underlying mechanisms.

  9. Mechano-activated surface modification of calcium carbonate in wet stirred mill and its properties

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Surface modification of calcium carbonate particles using sodium stearate(SDS) as a modification agent incorporated with the simultaneous wet ultra-fine grinding in the laboratory stirred mill was investigated. The physical properties and application properties of modified calcium carbonate were measured and evaluated. The action mechanism between SDS and calcium carbonate in the modification was studied by infrared spectrometry(IR) and X-ray photoelectron energy spectroscopy(XPS). The results indicate that the crushing mechanic force intensity can obviously influence the modification effect of calcium carbonate because of mechano-chemical effect. The hydrophilic surface of calcium carbonate is turned into hydrophobic after modification. The properties of polyethylene(PE) filled by modified calcium carbonate powder is markedly improved. And the adsorption of SDS could occur by chemical reaction with calcium carbonate surface.

  10. Calcium ion channel and epilepsy

    Institute of Scientific and Technical Information of China (English)

    Yudan Lü; Weihong Lin; Dihui Ma

    2006-01-01

    OBJECTIVE: To review the relationship between calcium ion channel and epilepsy for well investigating the pathogenesis of epilepsy and probing into the new therapeutic pathway of epilepsy.DATA SOURCES: A computer-based online research Calcium ion channel and epilepsy related articles published between January 1994 and December 2006 in the CKNI and Wanfang database with the key words of "calcium influxion, epilepsy, calcium-channel blocker". The language was limited to Chinese. At the same time,related articles published between January 1993 and December 2006 in Pubmed were searched for on online with the key words of "calcium influxion, epilepsy" in English.STUDY SELECTION: The materials were selected firstly. Inclusive criteria: ① Studies related to calcium ion channel and the pat1hogenesis of epilepsy. ② Studies on the application of calcium ion channel blocker in the treatment of epilepsy. Exclusive criteria: repetitive or irrelated studies.DATA EXTRACTION: According to the criteria, 123 articles were retrieved and 93 were excluded due to repetitive or irrelated studies. Altogether 30 articles met the inclusive criteria, 11 of them were about the structure and characters of calcium ion channel, 10 about calcium ion channel and the pathogenesis of epilepsy and 9 about calcium blocker and the treatment of epilepsy.DATA SYNTHESIS: Calcium ion channels mainly consist of voltage dependent calcium channel and receptor operated calcium channel. Depolarization caused by voltage gating channel-induced influxion is the pathological basis of epileptic attack, and it is found in many studies that many anti-epileptic drugs have potential and direct effect to rivalizing voltage-dependent calcium ion channel.CONCLUSION: Calcium influxion plays an important role in the seizure of epilepsy. Some calcium antagonists seen commonly are being tried in the clinical therapy of epilepsy that is being explored, not applied in clinical practice. If there are enough evidences to

  11. Catalytic pyrolysis using UZM-44 aluminosilicate zeolite

    Science.gov (United States)

    Nicholas, Christopher P; Boldingh, Edwin P

    2013-12-17

    A new family of aluminosilicate zeolites designated UZM-44 has been synthesized. These zeolites are represented by the empirical formula Na.sub.nM.sub.m.sup.k+T.sub.tAl.sub.1-xE.sub.xSi.sub.yO.sub.z where "n" is the mole ratio of Na to (Al+E), M represents a metal or metals from zinc, Group 1, Group 2, Group 3 and or the lanthanide series of the periodic table, "m" is the mole ratio of M to (Al+E), "k" is the average charge of the metal or metals M, T is the organic structure directing agent or agents, and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-44 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  12. Solar Imagery - Chromosphere - Calcium

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of full-disk images of the sun in Calcium (Ca) II K wavelength (393.4 nm). Ca II K imagery reveal magnetic structures of the sun from about...

  13. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

    Alexander, R Todd; Cordat, Emmanuelle; Chambrey, Régine;

    2016-01-01

    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and...... renal tubule and then discuss why not all gene defects that cause renal tubular acidosis are associated with hypercalciuria and nephrocalcinosis....

  14. Precipitation of calcium carbonate from a calcium acetate and ammonium carbamate batch system

    Science.gov (United States)

    Prah, J.; Maček, J.; Dražič, G.

    2011-06-01

    In this paper, we report a novel approach for preparing precipitated calcium carbonate using solutions of ammonium carbamate and calcium acetate as the sources of calcium and carbon dioxide, respectively. Two different concentrations of the starting solutions at three different temperatures (15, 25 and 50 °C) were used for the reaction. The influence of temperature and concentration on the polymorphism and the resulting morphology of calcium carbonate are discussed. The most important parameter for controlling a particular crystal structure and precipitate morphology were the concentrations of the initial solutions. When initial solutions with lower concentrations were used, the crystal form of the precipitate changed with time. Regardless the different polymorphism at different temperatures, after one day only the calcite form was detected in all samples, regardless of at which temperature the samples were prepared. At higher concentrations, pure vaterite or a mixture of vaterite and calcite were present at the beginning of the experiment. After one day, pure vaterite was found in the samples that were prepared at 15 and 25 °C. If calcium carbonate precipitated at 50 °C, the XRD results showed a mixture of calcite and vaterite regardless of the time at which the sample was taken. The morphology of calcium carbonate particles prepared at various conditions changed from calcite cubes to spherical particles of vaterite and aragonite needles. When a low starting concentration was used, the morphology at the initial stage was strongly affected by the temperature at which the experiments were conducted. However, after one day only, cubes were present in all cases at low initial concentrations. In contrast, at high concentrations spherical particles precipitated at all three temperatures at the beginning of the reaction. Spherical particles were made up from smaller particles. Over time, the size of the particles was diminishing due to their disintegration into

  15. Distribution of Carbon, Calcium and Phosphorus in Dental Enamel Studied by Charged-Particle Activation Analysis

    International Nuclear Information System (INIS)

    Sections of sound human dental enamel embedded in a matrix of sulphur were bombarded by deuterons at 2.2 MeV. Nitrogen-13 is produced from carbon by the reaction 12C(d, n)13N, and 32P from phosphorus by the reaction 31P(d, p)32P. Exposure to a process plate for 40 min starting 4 min after bombardment gives an autoradiograph due almost entirely to 13N, whereas a photographic plate exposed for eight days, starting five days after irradiation, gives one due entirely to 32P. Similar autoradiographs have been obtained from 43Sc or 44Sc produced by bombardment of tooth sections with protons. During each bombardment, control samples with known contents of carbon, calcium or phosphorus were also bombarded for calibration purposes. The autoradiographs were examined with the help of a recording microdensitometer with an effective slit of 1.5 mm x 0.08 mm. Errors arising from various sources limit the accuracy of the method to about 10%. The sensitivity for carbon is such that within an area of about 0.1 mm2 a few tenths of a nanogram can be detected. It has been found that the total carbon content of enamel varies from 1.01 ± 0.04% to 1.58 ± 0.05% for molars, and 0.92 ± 0.04% to 1.38 ± 0.05% for premolars, for values at the outer surface and the amelodentinal junction respectively. This variation is roughly linear. The concentration gradients for calcium and phosphorus are very much smaller and may be little larger than the probable errors. (author)

  16. Distribution of calcium ions in hydrolyses products of proto-pectin of sunflower head

    International Nuclear Information System (INIS)

    The purpose of present work is determination calcium ions containing in hydrolyses products of proto-pectins of sunflowers heads which let elaborate optimal method of high quality pectin obtaining. Obtained data in this article indicate that at least one of chemical reactions at hydrolysis passes with participations calcium ions

  17. Investigation of the By-products Formed during the Catalytic Synthesis of 4,4'-Methylenedimethyldiphenylcarbamate

    Institute of Scientific and Technical Information of China (English)

    QIU, Ze-Gang; WANG, Jun-Wei; KANG, Mao-Qing; LI, Qi-Feng; DU, Hui; WANG, Xin-Kui

    2007-01-01

    The structures of the by-products formed during the catalytic synthesis of 4,4'-methylenedimethyldiphenylcarbamate (MDC) by the reaction of 4,4'-methylenedianiline (MDA) with dimethyl carbonate (DMC) were identified and then the mechanisms of their formation were proposed.

  18. ACTION OF SILICATO OF CALCIUM AND MAGNESIUM IN THE REDUCTION Cercospora

    OpenAIRE

    Franciane Diniz Cogo; Gabriel Sergio Graciano; Katia Alves Campos

    2011-01-01

    The aim of this study was to evaluate the response of coffee plants (Coffea arabica) Catuaí IAC-44 with different doses of calcium silicate and magnesium in relation to incidence of Cercospora spot coffeicola and plant growth. The experiment was conducted in nursery seedling production of coffee from the Federal Institute of Southern Minas Gerais, Campus Machado, MG randomized blocks with five replications and the treatment used a source of silicon, calcium silicate and magnesium in doses - 0...

  19. Fruit Calcium: Transport and Physiology

    Science.gov (United States)

    Hocking, Bradleigh; Tyerman, Stephen D.; Burton, Rachel A.; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  20. Fruit Calcium: Transport and Physiology.

    Science.gov (United States)

    Hocking, Bradleigh; Tyerman, Stephen D; Burton, Rachel A; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  1. Calcium and calcitonin responses to calcium infusion in type I diabetes mellitus.

    OpenAIRE

    Amado, J. A.; C. Gomez; Obaya, S.; Otero, M; Gonzalez-Macias, J

    1987-01-01

    We studied calcium and calcium and calcitonin responses to intravenous calcium infusion (3 mg of elemental calcium/kg of body weight in 10 minutes) in 21 type I diabetic males and 17 age-matched normal males. Baseline total calcium, parathyroid hormone and calcitonin levels were normal in the diabetic group, but ionized calcium was lowered. Cortical bone status and osteocalcin levels were normal, suggesting a normal osteoblastic function. Total calcium and ionized calcium responses to calcium...

  2. Calmodulin activation by calcium transients in the postsynaptic density of dendritic spines.

    Directory of Open Access Journals (Sweden)

    Daniel X Keller

    Full Text Available The entry of calcium into dendritic spines can trigger a sequence of biochemical reactions that begins with the activation of calmodulin (CaM and ends with long-term changes to synaptic strengths. The degree of activation of CaM can depend on highly local elevations in the concentration of calcium and the duration of transient increases in calcium concentration. Accurate measurement of these local changes in calcium is difficult because the spaces are so small and the numbers of molecules are so low. We have therefore developed a Monte Carlo model of intracellular calcium dynamics within the spine that included calcium binding proteins, calcium transporters and ion channels activated by voltage and glutamate binding. The model reproduced optical recordings using calcium indicator dyes and showed that without the dye the free intracellular calcium concentration transient was much higher than predicted from the fluorescent signal. Excitatory postsynaptic potentials induced large, long-lasting calcium gradients across the postsynaptic density, which activated CaM. When glutamate was released at the synapse 10 ms before an action potential occurred, simulating activity patterns that strengthen hippocampal synapses, the calcium gradient and activation of CaM in the postsynaptic density were much greater than when the order was reversed, a condition that decreases synaptic strengths, suggesting a possible mechanism underlying the induction of long-term changes in synaptic strength. The spatial and temporal mechanisms for selectivity in CaM activation demonstrated here could be used in other signaling pathways.

  3. Calcium Oxide Supported on Monoclinic Zirconia as a Highly Active Solid Base Catalyst

    NARCIS (Netherlands)

    Frey, A.M.; Haasterecht, van T.; Jong, de K.P.; Bitter, J.H.

    2013-01-01

    Calcium oxide supported on ZrO2 is a highly active catalyst for base-catalyzed reactions such as aldol-type reactions and transesterification reactions. The role of key parameters during preparation, that is, impregnation versus precipitation, heat treatment, and metal oxide loading on the basicity

  4. DISTILLATION OF CALCIUM

    Science.gov (United States)

    Barton, J.

    1954-07-27

    This invention relates to an improvement in the process for the purification of caicium or magnesium containing an alkali metal as impurity, which comprises distiiling a batch of the mixture in two stages, the first stage distillation being carried out in the presence of an inert gas at an absolute pressure substantially greater than the vapor pressure of calcium or maguesium at the temperature of distillation, but less than the vaper pressure at that temperature of the alkali metal impurity so that only the alkali metal is vaporized and condensed on a condensing surface. A second stage distilso that substantially only the calcium or magnesium distills under its own vapor pressure only and condenses in solid form on a lower condensing surface.

  5. Models of calcium signalling

    CERN Document Server

    Dupont, Geneviève; Kirk, Vivien; Sneyd, James

    2016-01-01

    This book discusses the ways in which mathematical, computational, and modelling methods can be used to help understand the dynamics of intracellular calcium. The concentration of free intracellular calcium is vital for controlling a wide range of cellular processes, and is thus of great physiological importance. However, because of the complex ways in which the calcium concentration varies, it is also of great mathematical interest.This book presents the general modelling theory as well as a large number of specific case examples, to show how mathematical modelling can interact with experimental approaches, in an interdisciplinary and multifaceted approach to the study of an important physiological control mechanism. Geneviève Dupont is FNRS Research Director at the Unit of Theoretical Chronobiology of the Université Libre de Bruxelles;Martin Falcke is head of the Mathematical Cell Physiology group at the Max Delbrück Center for Molecular Medicine, Berlin;Vivien Kirk is an Associate Professor in the Depar...

  6. Can serum isotope levels accurately measure intestinal calcium absorption compared to gold-standard methods?

    OpenAIRE

    Vreede, Andrew P; Jones, Andrea N; Hansen, Karen E

    2015-01-01

    Background Low fractional calcium absorption (FCA) contributes to osteoporosis but is not measured clinically, as the gold-standard method requires administration of two calcium tracers and a subsequent 24-h urine collection. We evaluated alternate methods to measure FCA, compared to the gold standard method. Methods We administered two stable calcium isotope tracers (~8 mg oral 44Ca and ~3 mg intravenous 42Ca) with breakfast to 20 fasting post-menopausal women (Cohort 1) 59 ± 7 years old wit...

  7. Reverse calcium affinity purification of Fab with calcium derivatized hydroxyapatite

    OpenAIRE

    Gagnon, Pete; Cheung, Chia-wei; Yazaki, Paul J.

    2009-01-01

    This study introduces the application of calcium-derivatized hydroxyapatite for purification of Fab. Fab binds to native hydroxyapatite but fails to bind to the calcium derivatized form. IgG, Fc, and most other protein contaminants bind to the calcium form. This supports Fab purification by a simple flow-through method that achieves greater than 95% purity from papain digests and mammalian cell culture supernatants. Alternatively, Fab can be concentrated on native hydroxyapatite then eluted s...

  8. Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.

    OpenAIRE

    Qiu, S M; Wen, G.; Hirakawa, N; Soloway, R D; Hong, N K; Crowther, R S

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline...

  9. Reaction mechanism and nuclear correlations study by low energy pion double charge exchange

    International Nuclear Information System (INIS)

    In pion double-charge-exchange (DCX) reactions, a positive (negative) pion is incident on a nucleus and a negative (positive) pion emerges. These reactions are of fundamental interest since the process must involve at least two nucleons in order to conserve charge. Although two nucleon processes are present in many reactions they are usually masked by the dominant single nucleon processes. DCX is unique in that respect since it is a two nucleon process in lowest order and thus may be sensitive to two-nucleon correlations. Measurements of low energy pion double-charge-exchange reactions to the double-isobaric-analog-state (DIAS) and ground-state (GS) of the residual nucleus provide new means for studying nucleon-nucleon correlations in nuclei. At low energies (Tπ 7/2 shell at energies ranging from 25 to 65 MeV. Cross sections were measured on 42,44,48Ca, 46,50Ti and 54Fe. The calcium isotopes make a good set of nuclei on which to study the effects of correlations in DCX reactions

  10. [Study on the Influence of Mineralizer on the Preparation of Calcium Aluminates Based on Infrared Spectroscopy].

    Science.gov (United States)

    Fan, Wei; Wang, Liang; Zheng, Huai-li; Chen, Wei; Tang, Xiao-min; Shang, Juan-fang; Qian, Li

    2015-05-01

    In this study, effect of mineralizer on the structure and spectraproperties of calcium aluminates formation was extensively studied. Medium or low-grade bauxite and calcium carbonate were used as raw material and mineralizer CaF2 as additive. Calcium aluminates can be obtained after mixing fully, calcination and grinding. The prepared calcium aluminates can be directly used for the production of polyaluminiumchloride (PAC), polymeric aluminum sulfate, sodium aluminate and some other water treatment agents. The calcium aluminates preparation technology was optimized by investigating the mass ratio of raw materials (bauxiteand calcium carbonate) and mineralizer CaF2 dosage. The structure and spectra properties of bauxite and calcium aluminates were characterized by Fourier transform infrared(FTIR) spectroscopy analysis and the mineralization mechanism of the mineralizer was studied. FTIR spectra indicated that the addition of mineralizer promoted the decomposition and transformation of the diaspore, gibbsite and kaolinite, the decomposition of calcium carbonate, and more adequately reaction between bauxite and calcium carbonate. In addition, not only Ca in calcium carbonate and Si in bauxite were more readily reacted, but also Si-O, Si-O-Al and Al-Si bonds in the bauxite were more fractured which contributed to the release of Al in bauxite, and therefore, the dissolution rate of Al2O3 could be improved. The dissolution rate of Al2O3 can be promoted effectively when the mineralizer CaF2 was added in a mass ratio amount of 3%. And the mineralizer CaF2 cannot be fully functioned, when its dosage was in a mass percent of 1. 5%. Low-grade bauxite was easier to sinter for the preparation of calcium aluminates comparing with the highgrade one. The optimum material ratio for the preparation of calcium aluminates calcium at 1 250 °C was the mass ratio between bauxite and calcium carbonate of 1 : 0. 6 and mineralizer CaF2 mass ratio percent of 3%. PMID:26415430

  11. Kinetics and mechanisms of heterogeneous reaction of NO2 on CaCO3 surfaces under dry and wet conditions

    Directory of Open Access Journals (Sweden)

    Z. M. Chen

    2009-03-01

    Full Text Available Calcium nitrate (Ca(NO32 was observed in mineral dust and could change the hygroscopic and optical properties of mineral dust significantly due to its strong water solubility. The reaction of calcium carbonate (CaCO3 with nitric acid (HNO3 is believed the main reason for the observed Ca(NO32 in the mineral dust. In the atmosphere, the concentration of nitrogen dioxide (NO2 is orders of magnitude higher than that of HNO3; however, little is known about the reaction of NO2 with CaCO3. In this study, the heterogeneous reaction of NO2 on the surface of CaCO3 particles was investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS combined with X-ray photoelectron spectroscopy (XPS and scanning electron microscopy (SEM under wet and dry conditions. Nitrate formation was observed in both conditions, and nitrite was observed under wet conditions, indicating the reaction of NO2 on the CaCO3 surface produced nitrate and probably nitrous acid (HONO. Relative humidity (RH influenced both the initial uptake coefficient and the reaction mechanism. With RH52%, a monolayer of water formed on the surface of the CaCO3 particles, which reacted with NO2 as a first order reaction, forming HNO3 and HONO. The initial uptake coefficient γ0 was determined to be (1.66±0.38×10−7 under dry conditions and up to (0.84±0.44×10−6 under wet conditions. Considering that NO2 concentrations in the atmosphere are orders of magnitude higher than those of HNO3, the reaction of NO2 on CaCO3 particle should have similar importance as that of HNO3 in the atmosphere and could also be an important source of HONO in the atmosphere.

  12. Calcium – how and why?

    Indian Academy of Sciences (India)

    J K Jaiswal

    2001-09-01

    Calcium is among the most commonly used ions, in a multitude of biological functions, so much so that it is impossible to imagine life without calcium. In this article I have attempted to address the question as to how calcium has achieved this status with a brief mention of the history of calcium research in biology. It appears that during the origin and early evolution of life the Ca2+ ion was given a unique opportunity to be used in several biological processes because of its unusual physical and chemical properties.

  13. Calcium Phosphate Biomaterials: An Update

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Current calcium phosphate (CaP) biomaterials for bone repair, substitution, augmentation and regeneration include hydroxyapatite ( HA ) from synthetic or biologic origin, beta-tricalcium phosphate ( β-TCP ) , biphasic calcium phosphate (BCP), and are available as granules, porous blocks, components of composites (CaP/polymer) cements, and as coatings on orthopedic and dental implants. Experimental calcium phosphate biomaterials include CO3- and F-substituted apatites, Mg-and Zn-substituted β-TCP, calcium phosphate glasses. This paper is a brief review of the different types of CaP biomaterials and their properties such as bioactivity, osteoconductivity, osteoinductivity.

  14. 21 CFR 573.240 - Calcium periodate.

    Science.gov (United States)

    2010-04-01

    ... with calcium hydroxide or calcium oxide to form a substance consisting of not less than 60 percent by... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240 Food... Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used...

  15. 21 CFR 573.260 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  16. Calcium measurement methods

    Directory of Open Access Journals (Sweden)

    CarloAlberto Redi

    2010-09-01

    Full Text Available Rightly stressed by prof. Wolfgang Walz in the Preface to the series Neuromethods series, the “careful application of methods is probably the most important step in the process of scientific inquiry”. Thus, I strongly suggest to all those interested in calcium signaling and especially to the new-comers in the hot topic of neuroscience (which has so much space even in science-society debate for its implications in legal issues and in the judge-decision process to take profit from this so well edited book. I am saying this since prof. Verkhratsky and prof. Petersen......

  17. Extracellular calcium sensing and extracellular calcium signaling

    Science.gov (United States)

    Brown, E. M.; MacLeod, R. J.; O'Malley, B. W. (Principal Investigator)

    2001-01-01

    , localized changes in Ca(o)(2+) within the ECF can originate from several mechanisms, including fluxes of calcium ions into or out of cellular or extracellular stores or across epithelium that absorb or secrete Ca(2+). In any event, the CaR and other receptors/sensors for Ca(o)(2+) and probably for other extracellular ions represent versatile regulators of numerous cellular functions and may serve as important therapeutic targets.

  18. 26 CFR 44.0-1 - Introduction.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Introduction. 44.0-1 Section 44.0-1 Internal... ON WAGERING; EFFECTIVE JANUARY 1, 1955 Introduction § 44.0-1 Introduction. (a) In general. The... provisions of subtitle F of the Code (Procedure and Administration) which have special application to...

  19. 40 CFR 230.44 - Coral reefs.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Coral reefs. 230.44 Section 230.44... Aquatic Sites § 230.44 Coral reefs. (a) Coral reefs consist of the skeletal deposit, usually of calcareous... by increasing the level of suspended particulates. Coral organisms are extremely sensitive to...

  20. 12 CFR 561.44 - Security.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Security. 561.44 Section 561.44 Banks and... SAVINGS ASSOCIATIONS § 561.44 Security. The term security means any non-withdrawable account, note, stock... commonly known as a security, or any certificate of interest or participation in, temporary or...

  1. 7 CFR 930.44 - Quality control.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Quality control. 930.44 Section 930.44 Agriculture... MICHIGAN, NEW YORK, PENNSYLVANIA, OREGON, UTAH, WASHINGTON, AND WISCONSIN Order Regulating Handling Quality Control § 930.44 Quality control. (a) Quality standards. The Board may establish, with the approval of...

  2. 18 CFR 420.44 - Cooling water.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Cooling water. 420.44 Section 420.44 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Charges; Exemptions § 420.44 Cooling water. Water...

  3. 45 CFR 96.44 - Community services.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Community services. 96.44 Section 96.44 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION BLOCK GRANTS Direct Funding of Indian Tribes and Tribal Organizations § 96.44 Community services. (a) This section applies to...

  4. 30 CFR 44.6 - Service.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Service. 44.6 Section 44.6 Mineral Resources... RULES OF PRACTICE FOR PETITIONS FOR MODIFICATION OF MANDATORY SAFETY STANDARDS General § 44.6 Service... modification may be served personally or by first class mail to the last known address of the party....

  5. 29 CFR 452.44 - Dual unionism.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false Dual unionism. 452.44 Section 452.44 Labor Regulations Relating to Labor OFFICE OF LABOR-MANAGEMENT STANDARDS, DEPARTMENT OF LABOR LABOR-MANAGEMENT STANDARDS... OF 1959 Candidacy for Office; Reasonable Qualifications § 452.44 Dual unionism. While the Act...

  6. 10 CFR 851.44 - Administrative appeal.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Administrative appeal. 851.44 Section 851.44 Energy DEPARTMENT OF ENERGY WORKER SAFETY AND HEALTH PROGRAM Enforcement Process § 851.44 Administrative appeal. (a... calendar days from receipt of the final notice. (b) In order to exhaust administrative remedies...

  7. 4 CFR 4.4 - Incentive awards.

    Science.gov (United States)

    2010-01-01

    ... 4 Accounts 1 2010-01-01 2010-01-01 false Incentive awards. 4.4 Section 4.4 Accounts GOVERNMENT ACCOUNTABILITY OFFICE PERSONNEL SYSTEM EMPLOYEE PERFORMANCE AND UTILIZATION § 4.4 Incentive awards. The provisions of chapter 45 of title 5, United States Code and Office of Personnel Management...

  8. 27 CFR 44.254 - Shipping containers.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Shipping containers. 44.254 Section 44.254 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU... Requirements § 44.254 Shipping containers. Each shipping case, crate, or other container, in which cigars...

  9. 34 CFR 300.44 - Universal design.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Universal design. 300.44 Section 300.44 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND... DISABILITIES General Definitions Used in This Part § 300.44 Universal design. Universal design has the...

  10. 45 CFR 74.44 - Procurement procedures.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Procurement procedures. 74.44 Section 74.44 Public... Suspension.” (See 45 CFR part 76.) (e) Recipients shall, on request, make available for the HHS awarding..., AND COMMERCIAL ORGANIZATIONS Post-Award Requirements Procurement Standards § 74.44...

  11. 48 CFR 44.307 - Reports.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Reports. 44.307 Section 44... SUBCONTRACTING POLICIES AND PROCEDURES Contractors' Purchasing Systems Reviews 44.307 Reports. The ACO shall distribute copies of CPSR reports; notifications granting, withholding, or withdrawing system approval;...

  12. 29 CFR 44.3 - Election process.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Election process. 44.3 Section 44.3 Labor Office of the... WITH DEPARTMENT OF LABOR § 44.3 Election process. (a) Process. The Commissioner of Labor Statistics of... shall conduct the elections. The Commissioner shall provide a ballot containing the names of...

  13. Multilevel complexity of calcium signaling:Modeling angiogenesis

    Institute of Scientific and Technical Information of China (English)

    Luca; Munaron; Marco; Scianna

    2012-01-01

    Intracellular calcium signaling is a universal,evolutionary conserved and versatile regulator of cell biochemistry.The complexity of calcium signaling and related cell machinery can be investigated by the use of experimental strategies,as well as by computational approaches.Vascular endothelium is a fascinating model to study the specific properties and roles of calcium signals at multiple biological levels.During the past 20 years,live cell imaging,patch clamp and other techniques have allowed us to detect and interfere with calcium signaling in endothelial cells(ECs),providing a huge amount of information on the regulation of vascularization(angiogenesis) in normal and tumoral tissues.These data range from the spatiotemporal dynamics of calcium within different cell microcompartments to those in entire multicellular and organized EC networks.Beside experimental strategies,in silico endothelial models,specifically designed for simulating calcium signaling,are contributing to our knowledge of vascular physiol-ogy and pathology.They help to investigate and predict the quantitative features of proangiogenic events moving through subcellular,cellular and supracellular levels.This review focuses on some recent developments of computational approaches for proangiogenic endothelial calcium signaling.In particular,we discuss the creation of hybrid simulation environments,which combine and integrate discrete Cellular Potts Models.They are able to capture the phenomenological mechanisms of cell morphological reorganization,migration,and intercellular adhesion,with single-cell spatiotemporal models,based on reaction-diffusion equations that describe the agonist-induced intracellular calcium events.

  14. Compartmentalization of the submembrane calcium activity during calcium influx and its significance in transmitter release.

    OpenAIRE

    Simon, S M; Llinás, R R

    1985-01-01

    Quantitative modeling indicates that, in presynaptic terminals, the intracellular calcium concentration profile during inward calcium current is characterized by discrete peaks of calcium immediately adjacent to the calcium channels. This restriction of intracellular calcium concentration suggests a remarkably well specified intracellular architecture such that calcium, as a second messenger, may regulate particular intracellular domains with a great degree of specificity.

  15. Calcium Aluminate Cement Hydration Model

    Directory of Open Access Journals (Sweden)

    Matusinović, T.

    2011-01-01

    Full Text Available Calcium aluminate cement (AC is a very versatile special cement used for specific applications. As the hydration of AC is highly temperature dependent, yielding structurally different hydration products that continuously alter material properties, a good knowledge of thermal properties at early stages of hydration is essential. The kinetics of AC hydration is a complex process and the use of single mechanisms models cannot describe the rate of hydration during the whole stage.This paper examines the influence of temperature (ϑ=5–20 °C and water-to-cement mass ratio (mH /mAC = 0.4; 0.5 and 1.0 on hydration of commercial iron-rich AC ISTRA 40 (producer: Istra Cement, Pula, Croatia, which is a part of CALUCEM group, Figs 1–3. The flow rate of heat generation of cement pastes as a result of the hydration reactions was measured with differential microcalorimeter. Chemically bonded water in the hydrated cement samples was determined by thermo-gravimetry.Far less heat is liberated when cement and water come in contact for the first time, Fig. 1, than in the case for portland cement (PC. Higher water-to-cement ratio increases the heat evolved at later ages (Fig. 3 due to higher quantity of water available for hydration. A significant effect of the water-to-cement ratio on the hydration rate and hydration degree showed the importance of water as being the limiting reactant that slows down the reaction early. A simplified stoichiometric model of early age AC hydration (eq. (8 based on reaction schemes of principal minerals, nominally CA, C12A7 and C4AF (Table 1, was employed. Hydration kinetics after the induction period (ϑ < 20 °C had been successfully described (Fig. 4 and Table 2 by a proposed model (eq. (23 which simultaneously comprised three main mechanisms: nucleation and growth, interaction at phase boundary, and mass transfer. In the proposed kinetic model the nucleation and growth is proportional to the amount of reacted minerals (eq

  16. Optimization of calcium phosphate fine ceramic powders preparation

    Science.gov (United States)

    Sezanova, K.; Tepavitcharova, S.; Rabadjieva, D.; Gergulova, R.; Ilieva, R.

    2013-12-01

    The effect of biomimetic synthesis method, reaction medium and further precursor treatments on the chemical and phase composition, crystal size and morphology of calcium phosphates was examined. Nanosized calcium phosphate precursors were biomimetically precipitated by the method of continuous precipitation in three types of reaction media at pH 8: (i) SBF as an inorganic electrolyte system; (ii) organic (glycerine) modified SBF (volume ratio of 1:1); (iii) polymer (10 g/l xanthan gum or 10 g/l guar gum) modified SBF (volume ratio of 1:1). After maturation (24 h) the samples were lyophilized, calcinated at 300°C for 3 hours, and washed with water, followed by new gelation, lyophilization and step-wise (200, 400, 600, 800, and 1000°C, each for 3 hours) sintering. The reaction medium influenced the chemical composition and particle size but not the morphology of the calcium phosphate powders. In all studied cases bi-phase calcium phosphate fine powders with well-shaped spherical grains, consisting of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) with a Ca/P ratio of 1.3 - 1.6 were obtained. The SBF modifiers decreased the particle size of the product in the sequence guar gum ˜ xanthan gum < glycerin < SBF medium.

  17. Synthesis, structure, and frequency-doubling effect of calcium cyanurate.

    Science.gov (United States)

    Kalmutzki, Markus; Ströbele, Markus; Wackenhut, Frank; Meixner, Alfred J; Meyer, H-Jürgen

    2014-12-15

    Calcium cyanurate is synthesized by reacting calcium chloride with potassium cyanate following a solid-state reaction. The formation of the new compound Ca3(O3C3N3)2 (CCY), which occurs by the cyclotrimerization of cyanate ions, was examined thermoanalytically and the crystal structure was determined by single-crystal structure analysis. The structure of CCY is closely related to the structure of the well-known oxoborate β-BaB2O4 (BBO). Second harmonic generation (SHG) measurements on crystal powders show a higher SHG efficiency for CCY than for BBO by about one order of magnitude. PMID:25345390

  18. Fas mRNA expression and calcium influx change in H2O2-induced apoptotic hepatocytes in vitro

    Institute of Scientific and Technical Information of China (English)

    Qi-Ping Lu; Lei Tian

    2005-01-01

    AIM: To investigate the relationship between Fas gene expression and calcium influx change in peroxide-induced apoptotic hepatocytes and the possible molecular mechanism of Rxa in protecting hepatocytes.METHODS: Single-cell Fas mRNA expression in H2O2-exposed L02 hepatocytes with or without treatment of Rxa,an extract from an anti-peroxidant, Radix Salviae Miltiorrhizae,was determined by all-cell patch clamp and single-cell reverse transcriptase polymerase chain reaction (RT-PCR). Transient calcium influx change ([Ca2+]i) in the cells was evaluated with all-cell patch clamp micro-fluorescence single-cytosolic free Ca2+ concentration technique. Fas protein expression, early apoptotic index (annexin-V+) and cell membrane change inthe cells were evaluated by immunohistochemistry, flow cytometry (FCM) and scan electron microscopy respectively.RESULTS: In cells exposed to H2O2 for 2 h, the specific lane for Fas mRNA was vivid on electrophoresis, with increased Fas protein expression, [Ca2+]i (from 143.66±34.21 to 1115.28±227.16), annexin-V+ index (from 4.00±0.79 to 16.18±0.72) and membrane vesicle formation. However, in cells exposed to H2O2 but pre-treated with Rxa, there was no increase in Fas mRNA or protein expression and [Ca2+]i (103.56±28.92). Annexin-V+ index (8.92±1.44) was lower than the controls (P<0.01), and the cell membrane was intact.CONCLUSION: H2O2 induces apoptosis of L02 cells by increasing cytosolic [Ca2+]i, and inducing Fas mRNA and protein expression. Rxa protects the L02 cells from apoptosis through anti-peroxidation, inhibition of calcium overloading and prevention of the activation of cytosolic Fas signal pathway.

  19. Study of the neutron decays of giant resonances excited by the inelastic scattering of {sup 36} Ar on {sup 90} Zr and {sup 94} Zr targets at 44 MeV/u: a signature of multiphonon states; Etude des decroissances par neutrons des resonances geantes excitees dans les reactions de diffusion inelastique d`{sup 36}Ar sur des cibles de {sup 90} Zr et {sup 94} Zr a 44MeV/u: une signature des etats multiphonons

    Energy Technology Data Exchange (ETDEWEB)

    Pascalon-Rozier, V.

    1997-01-13

    In inelastic heavy ion scattering, to angles near to the grazing angle, giant resonances (GR) are excited with very large differential cross sections. It has been shown that multiphonon states, states built with several GR quanta, can also been excited. These states can be revealed through the measurement of their decay by light particle emission. In this thesis, we report on the study of inelastic scattering of {sup 36}Ar at 44 MeV/u on target of {sup 90}Zr and {sup 94}Zr, measured in coincidence with neutrons detected with the EDEN multidetector. The analysis of the inelastic spectra show evidence for a structure at high excitation energy, exhibiting characteristics compatible with a two-photon excitation. The construction of missing energy spectra allows us to the study of the GR and the high energy structure. In both nuclei, the GR presents a direct decay branch of 8%, which yields informations on the microscopic structure of the resonance. A two phonon state, interpreted as two weakly coupled GR`s, built on one top of the other, and each phonon is expected to exhibit the same direct decay pattern as the GR. Such a simple decay is observed in the data, proving that the structure observed is due to the excitation of the two phonon state in both nuclei studied. Finally, we present a theoretical development based on Random Phase Approximation calculation, predicting that the two phonon state should be very harmonic. This result is in agreement with experimental studies of double phonon states over a large range of nuclei (from A = 12 to 208) carried out with several different probes. (author). 70 refs.

  20. Strength of the $E_{\\text{p}}$=1.842 MeV resonance in the $^{40}$Ca(p,$\\gamma$)$^{41}$Sc reaction revisited

    CERN Document Server

    Schmidt, Konrad; Anders, Michael; Bemmerer, Daniel; Caciolli, Antonio; Dietz, Mirco; Elekes, Zoltán; Junghans, Arnd R; Menzel, Marie-Luise; Schwengner, Ronald; Wagner, Andreas; Zuber, Kai

    2014-01-01

    The strength of the $E_{\\rm p} = 1.842$ MeV resonance in the $^{40}$Ca(p,$\\gamma$)$^{41}$Sc reaction is determined with two different methods: First, by an absolute strength measurement using calcium hydroxide targets, and second, relative to the well-determined strength of the resonance triplet at $E_\\alpha$ = 4.5 MeV in the $^{40}$Ca($\\alpha$,$\\gamma$)$^{44}$Ti reaction. The present new value of $\\omega\\gamma=(0.192\\pm0.017)$ eV is 37% (equivalent to $3.5\\sigma$) higher than the evaluated literature value. In addition, the ratio of the strengths of the 1.842 MeV $^{40}$Ca(p,$\\gamma$)$^{41}$Sc and 4.5 MeV $^{40}$Ca($\\alpha$,$\\gamma$)$^{44}$Ti resonances has been determined to be $0.0229\\pm0.0018$. The newly corrected strength of the 1.842-MeV resonance can be used in the future as a normalization point for experiments with calcium targets.

  1. Calcium requirements for Chinese adults by cross-sectional statistical analyses of calcium balance studies: an individual participant data and aggregate data meta-regression

    Institute of Scientific and Technical Information of China (English)

    Fang Aiping; Li Keji; Shi Haoyu; He Jingjing; Li He

    2014-01-01

    Background Chinese dietary reference intakes for calcium are largely based on foreign studies.We undertook metaregression to estimate calcium requirements for Chinese adults derived from calcium balance data in Chinese adults.Methods We searched PubMed,Cochrane CENTRAL,and SinoMed from inception to March 5,2014,by using a structured search strategy.The bibliographies of any relevant papers and journals were also screened for potentially eligible studies.We extracted a standardized data set from studies in Chinese adults that reported calcium balance data.The relationship between calcium intake and output was examined by an individual participant data (IPD) and aggregate data (AD) meta-regression.Results We identified 11 metabolic studies in Chinese adults within 18-60 years of age.One hundred and forty-one IPD (n=35) expressed as mg/d,127 IPD (n=32) expressed as mg·kg body wt-1·d-1,and 44 AD (n=132) expressed as mg/d were collected.The models predicted a neutral calcium balance (defined as calcium output (Y) equal to calcium intake (C)) at intakes of 460 mg/d (Y=0.60C+183.98) and 8.27 mg·kg body wt-1·d-1 (Y=0.60C+3.33)for IPD,or 409 mg/d (Y=0.66C+139.00) for AD.Calcium requirements at upper intakes were higher than that at lower intakes in all these models.Conclusion Calcium requirement for Chinese adults 18-60 years of age approximately ranges between 400 mg/d and 500 mg/d when consuming traditional plant-based Chinese diets.

  2. Vitamin D, Calcium, and Bone Health

    Science.gov (United States)

    ... Balance › Vitamin D, Calcium, and Bone Health Vitamin D, Calcium, and Bone Health March 2012 Download PDFs ... helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin D ...

  3. Calcium, vitamin D, and your bones

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000490.htm Calcium, vitamin D, and your bones To use the sharing ... and maintain strong bones. How Much Calcium and Vitamin D Do I Need? Amounts of calcium are ...

  4. Calcium transport in turtle bladder

    International Nuclear Information System (INIS)

    Unidirectional 45Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (JnetCa) was secretory (serosa to mucosa). Ouabain reversed JnetCa to an absorptive flux. Amiloride reduced both fluxes such that JnetCa was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, JnetCa decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, JnetCa was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45Ca content was ≅30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca2+-ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na+-K+-ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa

  5. An Improved Calcium Flame Test.

    Science.gov (United States)

    Pearson, Robert S.

    1985-01-01

    Indicates that the true red color of calcium can be obtained (using the procedure described by Sorm and Logowski) if the calcium ion solution is mixed with an equal volume of saturated ammonium bromide solution. Suggestions for flame tests of other elements are also noted. (JN)

  6. A calcium isotope test of end-Permian ocean acidification using biogenic apatite

    Science.gov (United States)

    Hinojosa, J.; Brown, S. T.; DePaolo, D. J.; Paytan, A.; Shen, S.; Chen, J.; Payne, J.

    2011-12-01

    Submarine erosional truncation of uppermost Permian carbonate strata has been interpreted to reflect ocean acidification coincident with the end-Permian mass extinction. Although this scenario is consistent with carbon isotope and paleontological data, several alternative scenarios, such as ocean overturn or collapse of the biological pump, can also account for the carbon isotope and paleontological evidence. Calcium isotopes provide a geochemical proxy to test between acidification and alternative scenarios. Specifically, a negative shift in the calcium isotope composition (δ44/40Ca) of seawater is predicted under the acidification scenario but not the alternatives. The δ44/40Ca of carbonate rocks from south China exhibits a negative excursion of approximately 0.3%, but this shift could result from either a change in the δ44/40Ca of seawater or a change in carbonate mineralogy because calcite and aragonite exhibit substantially different fractionation factors relative to seawater. To test whether the negative shift in δ44/40Ca reflects seawater δ44/40Ca or carbonate mineralogy, we measured the δ44/40Ca of conodont microfossils (calcium hydroxyapatite) from the global stratotype section for the Permian-Triassic boundary at Meishan, China. The conodont δ44/40Ca record shows a negative excursion similar in stratigraphic position and magnitude to that previously observed in carbonate rocks. Parallel negative excursions in the δ44/40Ca of carbonate rocks and conodont microfossils cannot be accounted for by a change in carbonate mineralogy but are consistent with a negative shift in the δ44/40Ca of seawater. These data add further support for the ocean acidification scenario, pointing toward strong similarities between the greatest catastrophe in the history of animal life and anticipated global change during the 21st century.

  7. Calcium isotopes in wine

    Science.gov (United States)

    Holmden, C. E.

    2011-12-01

    The δ 44/40Ca values of bottled wine vary between -0.76% to -1.55% on the seawater scale and correlate weakly with inverse Ca concentration and Mg/Ca ratio, such that the lowest δ 44/40Ca values have the highest Ca concentrations and lowest Mg/Ca ratios. The correlation is notable in the sense that the measured wines include both whites and reds sampled from different wine growing regions of the world, and cover a wide range of quality. Trends among the data yield clues regarding the cause of the observed isotopic fractionation. White wines, and wines generally perceived to be of lower quality, have lower δ 44/40Ca values compared to red wines and wines of generally perceived higher quality. Quality was assessed qualitatively through sensory evaluation, price, and scores assigned by critics. The relationship between δ 44/40Ca and wine quality was most apparent when comparing wines of one varietal from one producer from the same growing region. In the vineyard, wine quality is related to factors such as the tonnage of the crop and the ripeness of the grapes at the time of harvesting, the thickness of the skins for reds, the age of the vines, as well as the place where the grapes were grown (terroir). Quality is also influenced by winemaking practices such as fermentation temperature, duration of skin contact, and barrel ageing. Accordingly, the relationship between δ 44/40Ca and wine quality may originate during grape ripening in the vineyard or during winemaking in the cellar. We tested the grape ripening hypothesis using Merlot grapes sampled from a vineyard in the Okanagan, British Columbia, using sugar content (degrees Brix) as an indicator of ripeness. The grapes were separated into pulp, skin, and pip fractions and were analyzed separately. Thus far, there is no clear evidence for a systematic change in δ 44/40Ca values associated with progressive ripening of grapes in the vineyard. On the day of harvesting, the δ 44/40Ca value of juice squeezed from

  8. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    OpenAIRE

    Choksi Krishna; Shenoy Ashoka M; A. R. Shabharaya; Lala Minaxi

    2011-01-01

    The objective of present study is to evaluate the effects of calcium carbonate and calcium gluconate on acute and subacute inflammation and to study their possible interactions with Aspirin. Calcium carbonate (10 mg/kg) and calcium gluconate (5 mg/kg) were administered individually and also co-administered along with sub therapeutic dose Aspirin (50mg/kg) to study their interaction. The inflammation was induced by carrageenan or a foreign body. Both calcium carbonate and calcium gluconate cou...

  9. Simvastatin inhibits CD44 fragmentation in chondrocytes.

    Science.gov (United States)

    Terabe, Kenya; Takahashi, Nobunori; Takemoto, Toki; Knudson, Warren; Ishiguro, Naoki; Kojima, Toshihisa

    2016-08-15

    In human osteoarthritic chondrocytes, the hyaluronan receptor CD44 undergoes proteolytic cleavage at the cell surface. CD44 cleavage is thought to require transit of CD44 into cholesterol-rich lipid rafts. The purpose of this study was to investigate whether statins exert a protective effect on articular chondrocytes due to diminution of cholesterol. Three model systems of chondrocytes were examined including human HCS-2/8 chondrosarcoma cells, human osteoarthritic chondrocytes and normal bovine articular chondrocytes. Treatment with IL-1β + Oncostatin M resulted in a substantial increase in CD44 fragmentation in each of the three chondrocyte models. Pre-incubation with simvastatin prior to treatment with IL-1β + Oncostatin M decreased the level of CD44 fragmentation, decreased the proportion of CD44 that transits into the lipid raft fractions, decreased ADAM10 activity and diminished the interaction between CD44 and ADAM10. In HCS-2/8 cells and bovine articular chondrocytes, fragmentation of CD44 was blocked by the knockdown of ADAM10. Inhibition of CD44 fragmentation by simvastatin also resulted in improved retention of pericellular matrix. Addition of cholesterol and farnesyl-pyrophosphate reversed the protective effects of simvastatin. Thus, the addition of simvastatin exerts positive effects on chondrocytes including reduced CD44 fragmentation and enhanced the retention of pericellular matrix. PMID:27242325

  10. Diffusive spatio-temporal noise in a first-passage time model for intracellular calcium release

    KAUST Repository

    Flegg, Mark B.

    2013-01-01

    The intracellular release of calcium from the endoplasmic reticulum is controlled by ion channels. The resulting calcium signals exhibit a rich spatio-temporal signature, which originates at least partly from microscopic fluctuations. While stochasticity in the gating transition of ion channels has been incorporated into many models, the distribution of calcium is usually described by deterministic reaction-diffusion equations. Here we test the validity of the latter modeling approach by using two different models to calculate the frequency of localized calcium signals (calcium puffs) from clustered IP3 receptor channels. The complexity of the full calcium system is here limited to the basic opening mechanism of the ion channels and, in the mathematical reduction simplifies to the calculation of a first passage time. Two models are then studied: (i) a hybrid model, where channel gating is treated stochastically, while calcium concentration is deterministic and (ii) a fully stochastic model with noisy channel gating and Brownian calcium ion motion. The second model utilises the recently developed two-regime method [M. B. Flegg, S. J. Chapman, and R. Erban, "The two-regime method for optimizing stochastic reaction-diffusion simulations," J. R. Soc., Interface 9, 859-868 (2012)] in order to simulate a large domain with precision required only near the Ca2+ absorbing channels. The expected time for a first channel opening that results in a calcium puff event is calculated. It is found that for a large diffusion constant, predictions of the interpuff time are significantly overestimated using the model (i) with a deterministic non-spatial calcium variable. It is thus demonstrated that the presence of diffusive noise in local concentrations of intracellular Ca2+ ions can substantially influence the occurrence of calcium signals. The presented approach and results may also be relevant for other cell-physiological first-passage time problems with small ligand concentration

  11. Calcium intake and hypertension among obese adults in United States: associations and implications explored.

    Science.gov (United States)

    Chen, Y; Strasser, S; Cao, Y; Wang, K-S; Zheng, S

    2015-09-01

    The relationship between calcium intake and hypertension is receiving increased research attention. The prevalence of hypertension is high among the obese populations. Calcium is a mineral that influences blood pressure. The aim of the study was to examine the association between calcium intake and hypertension in a large nationally representative sample of obese American adults. A total of 14,408 obese adults aged 20 years or older were obtained from the 1999-2010 National Health and Nutrition Examination Survey. Analysis of variance and linear regression models were used to examine relationships between calcium intake and systolic blood pressure (SBP) as well as diastolic blood pressure (DBP). Multiple logistic regression models were used to examine the association between calcium intake and hypertension after adjusting for potential confounders and interactions, including: age, race, education level, alcohol use, smoking, diabetes status, sodium intake and potassium intake. Calcium intake was significantly lower for the hypertensive group compared with the normotensive group (Pobese female young adults aged 20-44 years and among non-diabetic obese adults. Based on ordinary linear regression analysis, a significant inverse relationship was detected, SBP and DBP decreased if calcium intake increased (SBP: regression coefficient estimate=-0.015, Pintake was negatively associated with the probability of hypertension (odds ratio (OR)=0.81, 95% confidence interval (CI): 0.74-0.87, Pintake in youngest adults (age 20-44 years) had the lowest likelihood of hypertension (OR=0.77, 95% CI: 0.64-0.93, Pintake and probability of hypertension was stronger among females (OR: 0.68, 95% CI: 0.55-0.84, Pobese adults. The protective effect of calcium intake and hypertension was found significantly in obese non-diabetic adults (OR: OR=0.77, 95% CI: 0.67-0.89, Pobese diabetic adults. SBP, DBP and calcium intake were log transformed for both ordinary linear regression analysis and

  12. Calcium binding protein-mediated regulation of voltage-gated calcium channels linked to human diseases

    Institute of Scientific and Technical Information of China (English)

    Nasrin NFJATBAKHSH; Zhong-ping FENG

    2011-01-01

    Calcium ion entry through voltage-gated calcium channels is essential for cellular signalling in a wide variety of cells and multiple physiological processes. Perturbations of voltage-gated calcium channel function can lead to pathophysiological consequences. Calcium binding proteins serve as calcium sensors and regulate the calcium channel properties via feedback mechanisms. This review highlights the current evidences of calcium binding protein-mediated channel regulation in human diseases.

  13. Calcium carbonate and calcium sulfate in Martian meteorite EETA79001

    Science.gov (United States)

    Gooding, J. L.; Wentworth, S. J.

    1987-01-01

    Chips of glassy Lithology C of EETA79001 were studied by scanning electron microscopy and energy dispersive X-ray spectroscopy to determine the mineralogy and petrogenesis of the glass that was shown by others to contain trapped Mars-like gases. Calcium carbonite was identified as massive to acicular crystals for which Ca, C, and O were the major elements. Calcium sulfate was identified as prismatic-acicular crystals with Ca and S as the major elements.

  14. 22 CFR 142.44 - Academic adjustments.

    Science.gov (United States)

    2010-04-01

    ... OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Postsecondary Education § 142.44 Academic... recipient's education program or activity. (c) Course examinations. In its examinations or other...

  15. 22 CFR 217.44 - Academic adjustments.

    Science.gov (United States)

    2010-04-01

    ... PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Postsecondary Education § 217.44 Academic... recipient's education program or activity. (c) Course examinations. In its course examinations or...

  16. 45 CFR 84.44 - Academic adjustments.

    Science.gov (United States)

    2010-10-01

    ... HANDICAP IN PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Postsecondary Education § 84.44... recipient's education program or activity. (c) Course examinations. In its course examinations or...

  17. Production of {sup 44}Ti in neutrino-driven aspherical supernova explosions

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Shin-ichiro [Kumamoto National College of Technology, 2659-2 Suya, Goshi 861-1102 (Japan); Ono, Masaomi; Hashimoto, Masa-aki [Department of Physics, School of Sciences, Kyushu University, Fukuoka 810-8560 (Japan); Kotake, Kei [National Astronomical Observatory Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan)

    2014-05-02

    We examine the synthesis of {sup 44}Ti in a neutrino-driven aspherical supernova (SN), focusing on reaction rates related to {sup 44}Ti and rotation of a progenitor. We have performed 2D hydrodynamic simulations of SN of a 15M{sub ⊙} progenitor, whose angular velocity is manually set to be a cylindrical distribution and have followed explosive nucleosynthesis in the ejecta. We find that the faster rates of {sup 40}Ca(α,γ){sup 44}Ti and the slower rate of {sup 44}Ti(α,p){sup 47}V lead to more massive ejection of {sup 44}Ti and {sup 56}Ni and larger ratios <{sup 44}Ti/{sup 56}Ni>. Faster rotation also results in more massive ejection of {sup 44}Ti and {sup 56}Ni. Ratios <{sup 44}Ti/{sup 56}Ni> are however independent from rotation. Large masses of {sup 44}Ti and large ratios observed in SN 1987A and Cas A (> 1O{sup −4}M{sub ⊙} and 1-2 respectively) are not realized in all the models.

  18. Fabrications of zinc-releasing biocement combining zinc calcium phosphate to calcium phosphate cement.

    Science.gov (United States)

    Horiuchi, Shinya; Hiasa, Masahiro; Yasue, Akihiro; Sekine, Kazumitsu; Hamada, Kenichi; Asaoka, Kenzo; Tanaka, Eiji

    2014-01-01

    Recently, zinc-releasing bioceramics have been the focus of much attention owing to their bone-forming ability. Thus, some types of zinc-containing calcium phosphate (e.g., zinc-doped tricalcium phosphate and zinc-substituted hydroxyapatite) are examined and their osteoblastic cell responses determined. In this investigation, we studied the effects of zinc calcium phosphate (ZCP) derived from zinc phosphate incorporated into calcium phosphate cement (CPC) in terms of its setting reaction and MC3T3-E1 osteoblast-like cell responses. Compositional analysis by powder X-ray diffraction analysis revealed that HAP crystals were precipitated in the CPC containing 10 or 30wt% ZCP after successfully hardening. However, the crystal growth observed by scanning electron microscopy was delayed in the presence of additional ZCP. These findings indicate that the additional zinc inhibits crystal growth and the conversion of CPC to the HAP crystals. The proliferation of the cells and alkaline phosphatase (ALP) activity were enhanced when 10wt% ZCP was added to CPC. Taken together, ZCP added CPC at an appropriate fraction has a potent promotional effect on bone substitute biomaterials. PMID:24090874

  19. Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes

    OpenAIRE

    Samigullin, Dmitry; Fatikhov, Nijaz; Khaziev, Eduard; Skorinkin, Andrey; Nikolsky, Eugeny; Bukharaeva, Ellya

    2015-01-01

    At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers—which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal—has hitherto been technically impossible. With the aim of quantifying both Ca2+ currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dy...

  20. Alpha clustering in Ti isotopes: 40,44,48Ca + α resonant scattering

    Directory of Open Access Journals (Sweden)

    Bailey Sam

    2016-01-01

    Full Text Available Measurements were made of the 4He(40,44,48Ca,α resonant scattering reactions at 180° and up to Ec.m. ~ 11.5MeV, using the Thick Target Inverse Kinematics technique. These measurements are discussed, with a focus on assessing their usefulness for investigating α-clustering in medium mass 44,48,52Ti nuclei.

  1. 4,4’-Bis(4-octylphenoxy-2,2’-bipyridine

    Directory of Open Access Journals (Sweden)

    Zhen-Ting Du

    2009-12-01

    Full Text Available 4,4’-Bis(4-octylphenoxy-2,2’-bipyridine which can be used in complexes of ruthenium was synthesized. This ligand bears a long chain for the purpose of increasing the solubility of the final complex. The synthesis was achieved through a nucleophilic aromatic substitution reaction of 4,4’-bromo-2,2’-bipyridine and 4-octylphenol.

  2. 4,4’-Bis(4-octylphenoxy)-2,2’-bipyridine

    OpenAIRE

    Zhen-Ting Du; Jun-Ru Wang; Ru Liu; Yan Xu

    2009-01-01

    4,4’-Bis(4-octylphenoxy)-2,2’-bipyridine which can be used in complexes of ruthenium was synthesized. This ligand bears a long chain for the purpose of increasing the solubility of the final complex. The synthesis was achieved through a nucleophilic aromatic substitution reaction of 4,4’-bromo-2,2’-bipyridine and 4-octylphenol.

  3. Variability of calcium absorption

    International Nuclear Information System (INIS)

    Variability in calcium absorption was estimated in three groups of normal subjects in whom Ca absorption was measured by standard isotopic-tracer methods at interstudy intervals ranging from 1 to 4 mo. Fifty absorption tests were performed in 22 subjects. Each was done in the morning after an overnight fast with an identical standard breakfast containing a Ca load of approximately 250 mg. Individual fractional absorption values were normalized to permit pooling of the data. The coefficient of variation (CVs) for absorption for the three groups ranged from 10.57 to 12.79% with the size of the CV increasing with interstudy duration. One other published study presenting replicate absorption values was analyzed in a similar fashion and was found to have a CV of absorption of 9.78%. From these data we estimate that when the standard double-isotope method is used to measure Ca absorption there is approximately 10% variability around any given absorption value within an individual human subject and that roughly two-thirds of this represents real biological variability in absorption

  4. Persistent luminescence in Ca8Zn(SiO4)4Cl2:Eu2+

    International Nuclear Information System (INIS)

    A new persistent, green emission is reported for europium activated Calcium Zinc Chlorosilicate (CZCS). The phosphor was prepared by the solid state reaction and characterized using XRD, PL and TL techniques. The decay was characterized by admixture of two exponential components with decay constants 20.2 and 101 s. - Highlights: ► New results on TL and persistent photoluminescence in Europium activated Calcium Zinc Chlorosilicate are reported. ► Intense green emission is observed. ► Long lasting emission observed after 254 nm irradiation. ► Two glow peaks at 135 and 170 °C observed.

  5. Biodiesel from sunflower oil in supercritical methanol with calcium oxide

    International Nuclear Information System (INIS)

    In this study, sunflower seed oil was subjected to the transesterification reaction with calcium oxide (CaO) in supercritical methanol for obtaining biodiesel. Methanol is used most frequently as the alcohol in the transesterification process. Calcium oxide (CaO) can considerably improve the transesterification reaction of sunflower seed oil in supercritical methanol. The variables affecting the methyl ester yield during the transesterification reaction, such as the catalyst content, reaction temperature and the molar ratio of soybean oil to alcohol, were investigated and compared with those of non-catalyst runs. The catalytic transesterification ability of CaO is quite weak under ambient temperature. At a temperature of 335 K, the yield of methyl ester is only about 5% in 3 h. When CaO was added from 1.0% to 3.0%, the transesterification speed increased evidently, while when the catalyst content was further enhanced to 5%, the yield of methyl ester slowly reached to a plateau. It was observed that increasing the reaction temperature had a favorable influence on the methyl ester yield. In addition, for molar ratios ranging from 1 to 41, as the higher molar ratios of methanol to oil were charged, the greater transesterification speed was obtained. When the temperature was increased to 525 K, the transesterification reaction was essentially completed within 6 min with 3 wt% CaO and 41:1 methanol/oil molar ratio

  6. Calcium-based multi-element chemistry for grid-scale electrochemical energy storage

    Science.gov (United States)

    Ouchi, Takanari; Kim, Hojong; Spatocco, Brian L.; Sadoway, Donald R.

    2016-01-01

    Calcium is an attractive material for the negative electrode in a rechargeable battery due to its low electronegativity (high cell voltage), double valence, earth abundance and low cost; however, the use of calcium has historically eluded researchers due to its high melting temperature, high reactivity and unfavorably high solubility in molten salts. Here we demonstrate a long-cycle-life calcium-metal-based rechargeable battery for grid-scale energy storage. By deploying a multi-cation binary electrolyte in concert with an alloyed negative electrode, calcium solubility in the electrolyte is suppressed and operating temperature is reduced. These chemical mitigation strategies also engage another element in energy storage reactions resulting in a multi-element battery. These initial results demonstrate how the synergistic effects of deploying multiple chemical mitigation strategies coupled with the relaxation of the requirement of a single itinerant ion can unlock calcium-based chemistries and produce a battery with enhanced performance. PMID:27001915

  7. Finite Element Model to Study One Dimensional Calcium Dyanmics in Cardiac Myocytes

    Science.gov (United States)

    Pathak, Kunal B.; Adlakha, Neeru

    2015-12-01

    The multi physical process involving calcium ions regulate expansion and contraction of cardiac myocytes. This mechanism of expansion and contraction of cardiac myocytes is responsible for contraction and expansion of heart for pumping of blood into arteries and receiving blood into heart from vein. Thus calcium dynamics in cardiac myocytes is responsible for the activities of the myocytes cells and functioning of the heart. The specific spatiotemporal calcium ion dynamics is required to trigger, sustain and terminate activity of the cell. In this paper an attempt has been done to propose a model to study calcium dynamics in cardiac myocytes for a one-dimensional unsteady state case. The model incorporates the process like diffusion, reaction involving source and excess buffers. Appropriate boundary conditions and initial conditions have been framed. The finite element method has been employed to obtain the solution. The numerical results have been used to study the effect of buffers and source influx on calcium dynamics in cardiac myocytes.

  8. Calcium-based multi-element chemistry for grid-scale electrochemical energy storage

    Science.gov (United States)

    Ouchi, Takanari; Kim, Hojong; Spatocco, Brian L.; Sadoway, Donald R.

    2016-03-01

    Calcium is an attractive material for the negative electrode in a rechargeable battery due to its low electronegativity (high cell voltage), double valence, earth abundance and low cost; however, the use of calcium has historically eluded researchers due to its high melting temperature, high reactivity and unfavorably high solubility in molten salts. Here we demonstrate a long-cycle-life calcium-metal-based rechargeable battery for grid-scale energy storage. By deploying a multi-cation binary electrolyte in concert with an alloyed negative electrode, calcium solubility in the electrolyte is suppressed and operating temperature is reduced. These chemical mitigation strategies also engage another element in energy storage reactions resulting in a multi-element battery. These initial results demonstrate how the synergistic effects of deploying multiple chemical mitigation strategies coupled with the relaxation of the requirement of a single itinerant ion can unlock calcium-based chemistries and produce a battery with enhanced performance.

  9. Radiolabeling of DOTATOC with the long-lived positron emitter {sup 44}Sc

    Energy Technology Data Exchange (ETDEWEB)

    Pruszynski, Marek; Majkowska-Pilip, Agnieszka [Centre of Radiochemistry and Nuclear Chemistry, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warszawa (Poland); Loktionova, Natalia S.; Eppard, Elisabeth [Institute of Nuclear Chemistry, Johannes Gutenberg-University of Mainz, Fritz-Strassmann-Weg 2, D-55128 Mainz (Germany); Roesch, Frank, E-mail: frank.roesch@uni-mainz.de [Institute of Nuclear Chemistry, Johannes Gutenberg-University of Mainz, Fritz-Strassmann-Weg 2, D-55128 Mainz (Germany)

    2012-06-15

    The positron-emitting radionuclide {sup 44}Sc with a half-life of 3.97 h and a {beta}{sup +} branching of 94.3% is of potential interest for clinical PET. As so far it is available from a {sup 44}Ti/{sup 44}Sc generator in Mainz, where long-lived {sup 44}Ti decays to no-carrier-added (nca) {sup 44}Sc. The {sup 44}Sc is a trivalent metal cation and should be suitable for complexation with many well established bifunctional chelators conjugated to peptides or other molecular targeting vectors. Thus, the aim of this work was to investigate the potential of {sup 44}Sc for labeling of DOTA-conjugated peptides. DOTA-D-Phe{sup 1}-Tyr{sup 3}-octreotide (DOTATOC) was used as a model molecule to study and optimize labeling procedure. Reaction parameters such as buffer conditions, concentration of peptide, pH range, reaction temperature and time were optimized. Addition of 21 nmol of DOTATOC to {sup 44}Sc in ammonium acetate buffer pH 4.0 provided labeling yields >98% within 25 min of heating in an oil-bath at 95 Degree-Sign C. This time can be reduced to 3 min only by applying microwave supported heating. {sup 44}Sc-DOTATOC was found to be stable in 0.9% NaCl, PBS pH 7.4, fetal calf and human serums, and also in the presence of competing metal cations (Fe{sup 3+}, Ca{sup 2+}, Cu{sup 2+}, Mg{sup 2+}), as well as other ligand competitors, like EDTA and DTPA, even after almost 25 h incubation at 37 Degree-Sign C. Present study shows that nca {sup 44}Sc forms stable complexes with the macrocyclic ligand DOTA and that {sup 44}Sc-DOTATOC and analog targeting vectors may be synthesized for further preclinical and clinical investigations. - Highlights: Black-Right-Pointing-Pointer Labeling of somatostatin analouges with positron emitter {sup 44}Sc was tested. Black-Right-Pointing-Pointer DOTATOC was labeled with {sup 44}Sc isotope. Black-Right-Pointing-Pointer Optimal conditions for {sup 44}Sc-DOTATOC synthesis were found. Black-Right-Pointing-Pointer Stability of {sup 44}Sc

  10. Calcium-sensitive immunoaffinity chromatography

    DEFF Research Database (Denmark)

    Henriksen, Maiken L; Lindhardt Madsen, Kirstine; Skjoedt, Karsten;

    2014-01-01

    homogeneity may be impossible due to contamination with abundant antigens. In this study, we purified the scarce, complement-associated plasma protein complex, collectin LK (CL-LK, complex of collectin liver 1 and kidney 1), by immunoaffinity chromatography using a calcium-sensitive anti-collectin-kidney-1 m......Ab. This antibody was characterized by binding to CL-LK at hypo- and physiological calcium concentrations and dissociated from CK-LK at hyperphysiological concentrations of calcium. We purified CL-LK from plasma to a purity of 41% and a yield of 38%, resulting in a purification factor of more than 88......,000 in a single step. To evaluate the efficiency of this new purification scheme, we purified CL-LK using the same calcium-sensitive mAb in combination with acidic elution buffer and by using calcium-dependent anti-CL-K1 mAbs in combination with EDTA elution buffer. We found that calcium...

  11. Vitamin D is positively associated with sperm motility and increases intracellular calcium in human spermatozoa

    DEFF Research Database (Denmark)

    Blomberg Jensen, Martin; Bjerrum, Poul J; Jessen, Torben E;

    2011-01-01

    BACKGROUND The vitamin D receptor (VDR) is expressed in human spermatozoa, and VDR-knockout mice and vitamin D (VD) deficiency in rodents results in impaired fertility, low sperm counts and a low number of motile spermatozoa. We investigated the role of activated VD (1,25(OH)(2)D(3)) in human......M). 1,25(OH)(2)D(3) increased intracellular calcium concentration in human spermatozoa through VDR-mediated calcium release from an intracellular calcium storage, increased sperm motility and induced the acrosome reaction in vitro. CONCLUSIONS 1,25(OH)(2)D(3) increased intracellular calcium...... concentration, sperm motility and induced the acrosome reaction in mature spermatozoa, and VD serum levels were positively associated with sperm motility, suggesting a role for VD in human sperm function....

  12. Production of a 44 Ti target and its cross section of thermal neutron capture

    International Nuclear Information System (INIS)

    A study of the production of a 44 Ti target was carried out aiming the determination of its thermal neutron capture cross-section. With this purpose, the cross-section of the reaction 45 Sc(p,2 n) 44 Ti was determined in the energies 16-, 18-, 20-22- and 45 MeV. The cross-section of the reactions (p,n) 45 Ti, (p,pn) 44m Sc, (p,pn) 44g Sc and (p,p2n)43 Sc were also measured. The results in the low energy region are in good agreement with a previous work by McGee et al. On the other hand, the cross-section at 45 MeV is different from McGee's result and indicates the existence of an abnormal behavior of the excitation function at higher energies. Furthermore, a radiochemical separation method was developed in order to eliminate Sc from the 44 Ti target which was irradiated with neutrons. It was possible to determine an upper limit for the cross-section of the reaction 44 Ti (n, γ) of 4 x 103 b. At last, it is presented a discussion of the results obtained and their possible astrophysical implications. (author)

  13. 16 CFR 4.4 - Service.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Service. 4.4 Section 4.4 Commercial... Service. (a) By the Commission. (1) Service of complaints, initial decisions, final orders and other..., registered or certified, and mailed; service under this provision is complete upon delivery of the...

  14. 44 CFR 206.438 - Project management.

    Science.gov (United States)

    2010-10-01

    ... Project management. (a) General. The State serving as grantee has primary responsibility for project management and accountability of funds as indicated in 44 CFR part 13. The State is responsible for ensuring... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Project management....

  15. 20 CFR 901.44 - Hearings.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Hearings. 901.44 Section 901.44 Employees' Benefits JOINT BOARD FOR THE ENROLLMENT OF ACTUARIES REGULATIONS GOVERNING THE PERFORMANCE OF ACTUARIAL SERVICES UNDER THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974 Suspension or Termination of...

  16. 38 CFR 4.44 - The bones.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false The bones. 4.44 Section 4... DISABILITIES Disability Ratings The Musculoskeletal System § 4.44 The bones. The osseous abnormalities incident... convalescence, and progress of recovery with development of permanent residuals. With shortening of a long...

  17. 27 CFR 44.187 - Shipping containers.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Shipping containers. 44.187 Section 44.187 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU... Shipping containers. Each shipping case, crate, or other container in which tobacco products, or...

  18. 44 CFR 78.3 - Responsibilities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Responsibilities. 78.3... ASSISTANCE § 78.3 Responsibilities. (a) Federal. The Administrator will allocate available funds to each FEMA... approval; and (5) Submit performance and financial reports to FEMA in compliance with 44 CFR 13.40 and...

  19. 36 CFR 1210.44 - Procurement procedures.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Procurement procedures. 1210.44 Section 1210.44 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER...

  20. 45 CFR 2543.44 - Procurement procedures.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Procurement procedures. 2543.44 Section 2543.44 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements...

  1. Cutoff dependence in lattice phi44 theory

    International Nuclear Information System (INIS)

    The author discusses corrections to the high temperature expansion of the lattice phi44 theory in 4 + epsilon dimensions using the renormalization group. He works with vertex functions, whose expansion is derived from an effective Lagrangian for large-cutoff behaviour. He concludes that the numerical phi44 results offer a test of the idea of asymptotic freedom. (HSI)

  2. 10 CFR 430.44 - Consolidation.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Consolidation. 430.44 Section 430.44 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS Petitions To Exempt State... common parties, common questions of fact and law, and where such consolidation would expedite or...

  3. 27 CFR 44.69 - Assessment.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Assessment. 44.69 Section..., WITHOUT PAYMENT OF TAX, OR WITH DRAWBACK OF TAX General § 44.69 Assessment. Whenever any person required... amount is nominal or the result of an evident mathematical error, no such assessment shall be made...

  4. 44 CFR 206.204 - Project performance.

    Science.gov (United States)

    2010-10-01

    ... accordance with 44 CFR 13.21, Payment. (c) Time limitations for completion of work—(1) Deadlines. The project... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Project performance. 206.204... § 206.204 Project performance. (a) General. This section describes the policies and...

  5. 27 CFR 44.227 - Customs procedure.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Customs procedure. 44.227..., WITHOUT PAYMENT OF TAX, OR WITH DRAWBACK OF TAX Drawback of Tax § 44.227 Customs procedure. The customs... having inspected the articles and supervised the lading thereof on the export carrier, the...

  6. A genetic polymorphism (rs17251221 in the calcium-sensing receptor gene (CASR is associated with stone multiplicity in calcium nephrolithiasis.

    Directory of Open Access Journals (Sweden)

    Yii-Her Chou

    Full Text Available Calcium nephrolithiasis is one of the most common causes of renal stones. While the prevalence of this disease has increased steadily over the last 3 decades, its pathogenesis is still unclear. Previous studies have indicated that a genetic polymorphism (rs17251221 in the calcium-sensing receptor gene (CASR is associated with the total serum calcium levels. In this study, we collected DNA samples from 480 Taiwanese subjects (189 calcium nephrolithiasis patients and 291 controls for genotyping the CASR gene. Our results indicated no significant association between the CASR polymorphism (rs17251221 and the susceptibility of calcium nephrolithiasis. However, we found a significant association between rs17251221 and stone multiplicity. The risk of stone multiplicity was higher in patients with the GG+GA genotype than in those with the AA genotype (chi-square test: P = 0.008; odds ratio  =  4.79; 95% confidence interval, 1.44-15.92; Yates' correction for chi-square test: P = 0.013. In conclusion, our results provide evidence supporting the genetic effects of CASR on the pathogenesis of calcium nephrolithiasis.

  7. Asante Calcium Green and Asante Calcium Red--novel calcium indicators for two-photon fluorescence lifetime imaging.

    Directory of Open Access Journals (Sweden)

    Karolina Jahn

    Full Text Available For a comprehensive understanding of cellular processes and potential dysfunctions therein, an analysis of the ubiquitous intracellular second messenger calcium is of particular interest. This study examined the suitability of the novel Ca2+-sensitive fluorescent dyes Asante Calcium Red (ACR and Asante Calcium Green (ACG for two-photon (2P-excited time-resolved fluorescence measurements. Both dyes displayed sufficient 2P fluorescence excitation in a range of 720-900 nm. In vitro, ACR and ACG exhibited a biexponential fluorescence decay behavior and the two decay time components in the ns-range could be attributed to the Ca(2+-free and Ca(2+-bound dye species. The amplitude-weighted average fluorescence decay time changed in a Ca(2+-dependent way, unraveling in vitro dissociation constants K(D of 114 nM and 15 nM for ACR and ACG, respectively. In the presence of bovine serum albumin, the absorption and steady-state fluorescence behavior of ACR was altered and its biexponential fluorescence decay showed about 5-times longer decay time components indicating dye-protein interactions. Since no ester derivative of ACG was commercially available, only ACR was evaluated for 2P-excited fluorescence lifetime imaging microscopy (2P-FLIM in living cells of American cockroach salivary glands. In living cells, ACR also exhibited a biexponential fluorescence decay with clearly resolvable short (0.56 ns and long (2.44 ns decay time components attributable to the Ca(2+-free and Ca(2+-bound ACR species. From the amplitude-weighted average fluorescence decay times, an in situ K(D of 180 nM was determined. Thus, quantitative [Ca(2+]i recordings were realized, unraveling a reversible dopamine-induced [Ca(2+]i elevation from 21 nM to 590 nM in salivary duct cells. It was concluded that ACR is a promising new Ca(2+ indicator dye for 2P-FLIM recordings applicable in diverse biological systems.

  8. Multimodal encoding in a simplified model of intracellular calcium signaling

    OpenAIRE

    De Pitta`, Maurizio; Volman, Vladislav; Levine, Herbert; Ben-Jacob, Eshel

    2009-01-01

    Many cells use calcium signalling to carry information from the extracellular side of the plasma membrane to targets in their interior. Since virtually all cells employ a network of biochemical reactions for Ca2+ signalling, much effort has been devoted to understand the functional role of Ca2+ responses and to decipher how their complex dynamics is regulated by the biochemical network of Ca2+-related signal transduction pathways. Experimental observations show that Ca2+ signals in response t...

  9. Fractional Absorption of Active Absorbable Algal Calcium (AAACa and Calcium Carbonate Measured by a Dual Stable-Isotope Method

    Directory of Open Access Journals (Sweden)

    Steven A. Abrams

    2010-07-01

    Full Text Available With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa, obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI, with that of calcium carbonate. In 10 postmenopausal women volunteers aged 59 to 77 years (mean ± S.D., 67 ± 5.3, the fractional calcium absorption of AAACa and CaCO3 was measured by a dual stable isotope method. 44Ca-enriched CaCO3 and AAACa were administered in all subjects one month apart. After a fixed-menu breakfast and pre-test urine collection (Urine 0, 42Ca-enriched CaCl2 was intravenously injected, followed by oral administration of 44Ca-enriched CaCO3 without carrier 15 minutes later, and complete urine collection for the next 24 hours (Urine 24. The fractional calcium absorption was calculated as the ratio of Augmentation of 44Ca from Urine 0 to Urine 24/ augmentation of 42Ca from Urine 0 to Urine 24. Differences and changes of 44Ca and 42Ca were corrected by comparing each with 43Ca. Fractional absorption of AAACa (mean ± S.D., 23.1 ± 6.4, was distinctly and significantly higher than that of CaCO3 (14.7 ± 6.4; p = 0.0060 by paired t-test. The mean fractional absorption was approximately 1.57-times higher for AAACa than for CaCO3. The serum 25(OH vitamin D level was low (mean ± S.D., 14.2 ± 4.95 ng/ml, as is common in this age group in Japan. Among the parameters of the bone and mineral metabolism measured, none displayed a significant correlation with the fractional absorption of CaCO3 and AAACa. Higher fractional absorption of AAACa compared with CaCO3 supports previous reports on the more beneficial effect of AAACa than CaCO3 for osteoporosis.

  10. Use of gas chromatography in the kinetics of decomposition of calcium carbonate

    International Nuclear Information System (INIS)

    Previous work has shown the utility of gas chromatography in studying the kinetics of the thermal composition of calcium carbonate. One of the advantages of this method is the possibility of characterizing and quantifying gaseous products by connecting a gas chromatograph at the exit of the reaction oven, which provides an easy system for studying the decomposition reaction. The calcium carbonate that was used was characterized by X-ray diffraction, scanning electron microscopy, BET surface area and particle size distribution by laser diffraction. The test conditions for the gas load flow in the reactor oven and the mass of calcium carbonate were determined at different reaction temperatures in order to eliminate the effect of diffusion on the speed of decomposition. The reactions were carried out with pro-analysis calcium carbonate in a quartz reactor, under isothermal conditions in a temperature range of 655oC to 715oC, using nitrogen as the gas load and with different sample masses. The gaseous products were analyzed at different reaction times and the instantaneous speed and rate of reaction were determined. The Flynn method was used to calculate the activation energy and the test results were adjusted with different kinetic models corresponding to solid state reactions. The area contracting model was the one that adjusted best (CW)

  11. Investigations of nano coated calcium hydroxide cycled in a thermochemical heat storage

    OpenAIRE

    Roßkopf, Christian; Afflerbach, Sandra; Schmidt, Matthias; Görtz, Burkhard; Torsten, Kowald; Linder, Marc; Reinhard, Trettin

    2015-01-01

    Thermochemical heat storage systems are a promising new technology for concentrated solar power plants and can contribute to improve the efficiency of industrial processes Neveu et al. (2013) [21]. However, for example for the reaction system calcium oxide/calcium hydroxide (CaO/Ca(OH)2), the good availability at low cost is accompanied by poor powder properties that demand complex reactor solutions. During thermochemical cycling agglomeration effects occur and originate inhomogeneity resulti...

  12. Mechanism of Calcium Fluoride Acceleration for Vacuum Carbothermic Reduction of Magnesia

    Science.gov (United States)

    Jiang, Yun; Liu, Yu-qin; Ma, Hong-wen; Zhou, Wei-gong

    2016-04-01

    The use of a small amount of calcium fluoride as an additive greatly accelerated the reduction of magnesia during the preparation of magnesium from magnesia using the vacuum carbothermic reduction method. At 1573 K (1300 °C), the magnesia reaction rates of the samples with 1, 3, and 5 pct CaF2 were all approximately 26 pct, three times that of free CaF2, and they were arranged in order of the calcium fluoride weight percentages at 1673 K (1400 °C). The residues were analyzed using chemical analysis, XRD, SEM, EDS, and XRF. The possible acceleration mechanism was discussed. Calcium fluoride combined with magnesia and silicon dioxide to form a eutectic that melted as a channel to aid the solid-solid reaction between carbon and magnesia at approximately 1573 K (1300 °C). Calcium fluoride in the molten state offered free calcium ions and fluorine ions. Fluorine ions entered and distorted the magnesia crystal lattice. The structural strength and chemical stability of the magnesia crystal lattice decreased, which facilitated the magnesia reduction by carbon. Calcium ions were employed to generate the calcium and magnesium silicate. The easyly evaporating fluorides, including magnesium fluoride and silicon tetrafluoride, were regarded as the main reason for the loss of fluorine.

  13. Effectiveness and Mechanisms of Defluorination of Perfluorinated Alkyl Substances by Calcium Compounds during Waste Thermal Treatment.

    Science.gov (United States)

    Wang, Fei; Lu, Xingwen; Li, Xiao-yan; Shih, Kaimin

    2015-05-01

    The mineralization of perfluorinated alkyl substances (PFASs) by calcium compounds during the waste thermal treatment was systemically studied. Different calcium compounds showed different mineralization efficiencies of PFASs during the thermal process, owing to the different reaction mechanisms. Calcium hydroxide was recommended as the most effective Ca reagent for PFAS defluorination because the carbon-fluorine bonds in PFASs can be converted to carbon-hydrogen bonds via the hydrodefluorination reaction. PFASs with different chain lengths and functional groups were further investigated for their potentially different mineralization behavior. The results showed that the chain length of PFASs had an insignificant effect on the mineralization efficiency by calcium hydroxide. The thermogravimetric analysis-differential thermal analysis (TGA-DTA) also revealed that perfluorooctanesulfonate (PFOS) and perfluorohexanesulfonate (PFHxS) (with different chain lengths) had a similar thermal behavior. However, PFASs with different functional groups showed different mineralization behavior with calcium hydroxide in relation to their different thermal decomposition temperatures. Finally, the mineralization ratio of polytetrafluoroethylene (PTFE) particles by calcium hydroxide could reach 80% or higher when the temperature was above 400 °C. The gas chromatography/mass spectrometry (GC/MS) results demonstrated much reduced production of gaseous fluorocarbon fragments during PTFE decomposition when coexisting with calcium hydroxide. PMID:25850557

  14. "Caged calcium" in Aplysia pacemaker neurons. Characterization of calcium-activated potassium and nonspecific cation currents

    OpenAIRE

    1989-01-01

    We have studied calcium-activated potassium current, IK(Ca), and calcium-activated nonspecific cation current, INS(Ca), in Aplysia bursting pacemaker neurons, using photolysis of a calcium chelator (nitr-5 or nitr-7) to release "caged calcium" intracellularly. A computer model of nitr photolysis, multiple buffer equilibration, and active calcium extrusion was developed to predict volume-average and front-surface calcium concentration transients. Changes in arsenazo III absorbance were used to...

  15. The human acrosome reaction

    Institute of Scientific and Technical Information of China (English)

    H.W.G.Baker; D.Y.Liu; C.Garrett; M.Martic

    2000-01-01

    We developed tests of sperm-oocyte interaction: sperm-zona binding, zona-induced acrosome reaction, spermzona penetration and sperm-oolemma binding, using oocytes which failed to fertilise in clinical in vitro fertilization (IVF). Although oocyte defects contribute to failure of sperm oocyte interaction, rarely are all oocytes from one woman affected. Low or zero fertilization in standard IVFwas usually caused by sperm abnormalities. Poor sperm-zona pellucida binding was frequently associated with failure of standard IVF and obvious defects of sperm motility or morphology. The size and shape of the acrosome is particularly important for sperm binding to the oocyte. The proportion of acrosome intact sperm in the insemination medium was related to the IVF rate. Inducing the acrosome reaction with a calcium ionophore reduced sperm-zona binding. Blocking acrosome dispersal with an acrosin inhibitor prevented spermzona penetration. Sperm-zona penetration was even more highly related to IVF rates than was sperm-zona binding. Some patients had low or zero fertilization rates with standard IVF but normal sperm by conventional tests and normal sperm-zona binding. Few of their sperm underwent the acrosome reaction on the surface of the zona and none penetrated the zona. In contrast, fertilization and pregnancy rates were high with intracytoplasmic sperm injection. We call thiscondition defective zona pellucida induced acrosome reaction. Discovery of the nature of the abnormalities in the signal transduction and effector pathways of the human zona pellucida induced acrosome reaction should result in simpler tests and treatments for the patients and also provide new leads for contraceptive development.

  16. The calcium concentration of public drinking waters and bottled mineral waters in Spain and its contribution to satisfying nutritional needs

    Directory of Open Access Journals (Sweden)

    Isidro Vitoria

    2014-07-01

    Full Text Available Introduction: A sufficient intake of calcium enables correct bone mineralization. The bioavailability of calcium in water is similar to that in milk. Objective: To determine the concentration of calcium in public drinking water and bottled mineral water. Methods: We used ion chromatography to analyse the calcium concentrations of public drinking waters in a representative sample of 108 Spanish municipalities (21,290,707 people and of 109 natural mineral waters sold in Spain, 97 of which were produced in Spain and 12 of which were imported. Results: The average calcium concentration of public drinking waters was 38.96 ± 32.44 mg/L (range: 0.40159.68 mg/L. In 27 municipalities, the water contained 50-100 mg/L of calcium and in six municipalities it contained over 100 mg/L. The average calcium concentration of the 97 Spanish natural mineral water brands was 39.6 mg/L (range: 0.6-610.1 mg/L. Of these, 34 contained 50-100 mg/L of calcium and six contained over 100 mg/L. Of the 12 imported brands, 10 contained over 50 mg/L. Assuming water consumption is as recommended, water containing 50-100 mg/L of calcium provides 5.4-12.8% of the recommended intake of calcium for children aged one to thirteen, up to 13.6% for adolescents, 5.8-17.6% for adults, and up to 20.8% for lactating mothers. Water with 100-150 mg/L of calcium provides 10-31% of the recommended dietary allowance, depending on the age of the individual. Discussion: Public drinking water and natural mineral water consumption in a third of Spanish cities can be considered an important complementary source of calcium.

  17. Effect of Preharvest Calcium Treatments on Sweet Cherry Fruit Quality

    OpenAIRE

    Deniz EROGUL

    2014-01-01

    In this study, the effects of different foliar calcium compounds on fruit cracking and quality of sweet cherry variety ‘0900 Ziraat’ were investigated. Calcium caseinate, calcium chloride, calcium hydroxide and calcium nitrate were used as foliar sprays. Calcium applications reduced the cracking index 38% to 66% compared to cherries that did not receive foliar treatment. The most efficient applications for decreasing cracking were calcium hydroxide and calcium chloride. Calcium chloride and c...

  18. Stochastic Simulation of Cardiac Ventricular Myocyte Calcium Dynamics and Waves

    OpenAIRE

    Tuan, Hoang-Trong Minh; Williams, George S.B.; Chikando, Aristide C.; Sobie, Eric A.; Lederer, W. Jonathan; Jafri, M. Saleet

    2011-01-01

    A three dimensional model of calcium dynamics in the rat ventricular myocyte was developed to study the mechanism of calcium homeostasis and pathological calcium dynamics during calcium overload. The model contains 20,000 calcium release units (CRUs) each containing 49 ryanodine receptors. The model simulates calcium sparks with a realistic spontaneous calcium spark rate. It suggests that in addition to the calcium spark-based leak, there is an invisible calcium leak caused by the stochastic ...

  19. Nuclear Reactions

    OpenAIRE

    Bertulani, C. A.

    2009-01-01

    Nuclear reactions generate energy in nuclear reactors, in stars, and are responsible for the existence of all elements heavier than hydrogen in the universe. Nuclear reactions denote reactions between nuclei, and between nuclei and other fundamental particles, such as electrons and photons. A short description of the conservation laws and the definition of basic physical quantities is presented, followed by a more detailed account of specific cases: (a) formation and decay of compound nuclei;...

  20. Aging and calcium as an environmental factor.

    Science.gov (United States)

    Fujita, T

    1985-12-01

    Calcium deficiency is a constant menace to land-abiding animals, including mammals. Humans enjoying exceptional longevity on earth are especially susceptible to calcium deficiency in old age. Low calcium and vitamin D intake, short solar exposure, decreased intestinal absorption, and falling renal function with insufficient 1,25(OH)2 vitamin D biosynthesis all contribute to calcium deficiency, secondary hyperparathyroidism, bone loss and possibly calcium shift from the bone to soft tissue, and from the extracellular to the intracellular compartment, blunting the sharp concentration gap between these compartments. The consequences of calcium deficiency might thus include not only osteoporosis, but also arteriosclerosis and hypertension due to the increase of calcium in the vascular wall, amyotrophic lateral sclerosis and senile dementia due to calcium deposition in the central nervous system, and a decrease in cellular function, because of blunting of the difference in extracellular-intracellular calcium, leading to diabetes mellitus, immune deficiency and others (Fig. 6). PMID:2943880

  1. Transport of Calcium Ions into Mitochondria.

    Science.gov (United States)

    Xu, Zhaolong; Zhang, Dayong; He, Xiaolan; Huang, Yihong; Shao, Hongbo

    2016-06-01

    To uptake calcium ions of mitochondria is of significant functional connotation for cells, because calcium ions in mitochondria are involved in energy production, regulatory signals transfer, and mitochondrial permeability transition pore opening and even programmed cell death of apoptosis, further playing more roles in plant productivity and quality. Cytoplasmic calcium ions access into outer mitochondrial membrane (OMM) from voltage dependent anion-selective channel (VDAC) and were absorbed into inner mitochondrial membrane (IMM) by mitochondrial calcium uniporter (MCU), rapid mitochondrial calcium uptake (RaM) or mitochondrial ryanodine receptor (mRyR). Although both mitochondria and the mechanisms of calcium transport have been extensively studied, but there are still long-standing or even new challenges. Here we review the history and recent discoveries of the mitochondria calcium ions channel complex involved calcium assimilation, and discuss the role of calcium ions into mitochondria. PMID:27252588

  2. Reaction of 1,3-di-tert-butyl-2,2-dimethyl-4,4-dichloro-1,3,2,4lambda4-diazasila-stannetidine with silver trifluoromethanesulphonate : the crystal structure of polymeric 1,3-di-tert-butyl-2,4-dimethyl-2,4-ditrifluoromethanesulphonate-1,3,2,4lambda 5-diazasilastannetidine

    OpenAIRE

    Veith, Michael; Royan, Bruce W.; Huch, Volker

    1993-01-01

    When 1,3-di-tert-butyl-2,2-dimethyl-4,4-dichloro-1,3,2,4lambda2-diazasilastannetid ine (1) is allowed to react with the chloride abstracting reagent AgCF3SO3 the chlorides are displaced by triflates forming 2. At the same time a rearrangement in the molecule takes place, one of the methyl groups on silicon migrating to tin in exchange of a triflate. In the solid the new compound 2 is a coordination polymer with trigonal bi-pyramidal tin centers, which exhibit quite unusual short Sn-N bonds in...

  3. The role of calcium in cell injury. A review.

    Science.gov (United States)

    Trump, B F; Berezesky, I K; Laiho, K U; Osornio, A R; Mergner, W J; Smith, M W

    1980-01-01

    The role of calcium in cell injury is currently under investigation in many laboratories. It appears that movement of calcium between extra- to intracellular compartments and between various intracellular compartments plays a key role in determining many important reactions of cells both to lethal and sublethal injuries of diverse types as well as in adaptive new steady states. Prevention and/or modification of calcium movements has implication for the control of cell population growth, the prevention of cancer, and the retrieval of victims of shock, myocardial infarction and stroke. Regardless of what type of initial injury occurs, for example ischemia or direct cell membrane damage, the cell undergoes calcium accumulation either by impaired energy metabolism and/or plasmalemmal alterations. This elevated intracellular calcium concentration is responsible for cytoskeletal modifications which alter cell shape, the activation of phospholipases which results in perpetuation of membrane damage and finally, mitochondrial calcification. Although such changes have been partially characterized biochemically and morphologically, some obscure points continue to need clarification. The importance of determing the event(s) responsible for cell death is directly related to the potential capability of their manipulation. Therefore, this could result in the development and/or modification of pharmacologic interventions for the control and prevention of many human diseases. It is the purpose of this paper to review the present state of the art regarding the role of calcium in cell injury, to put it into perspective concerning organelle changes from the standpoint of morphology, and to indicate the present and future role of analytical microscopy in furthering the understanding of these processes. PMID:6999604

  4. Curing process and kinetics of CMC/E44/DDM systems%CMC/E44/DDM体系固化过程及动力学

    Institute of Scientific and Technical Information of China (English)

    董红星; 赵庆晨; 张进; 陈野; 岳国君; 刘文信; 刘劲松; 刘立佳; 张春红

    2014-01-01

    The influence of sodium carboxy methyl cellulose (CMC) on the curing process of epoxy resin E44 with 4,4′-diamino diphenyl methane (DDM) was studied by using infrared spectra and thermal analytical methods. Infrared spectra indicated that the CMC contributed to forming more polyether structures during the curing process. The study of non-isothermal curing kinetics by differential scanning calorimeters (DSC) showed that CMC accelerated curing reaction of E44/DDM and reduced reaction activation energy in the initial reaction stage. The iso-conversional method and the autocatalytic model were used to analyze the curing process of E44/DDM and CMC/E44/DDM systems respectively. A kinetic model was built. The changes of activation energy (E)versus conversion (a) were obtained by the Starink’s iso-conversional method for E44/DDM system and CMC/E44/DDM systems respectively. The activation energy (E) of E44/DDM system was reduced obviously with increasing conversion. When CMC content was the same, activation energy of the CMC system with high molecular weight was higher than that with low molecular weight. However, for the CMC/E44/DDM system, as the degree of conversion increased, variation ofE was not obvious. The SB (m,n) autocatalytic kinetic model was used to describe the curing reaction process of the studied system. The model parameters were calculated by using the Levenberg-Marquardt method. The SB model showed a good agreement with experimental data of CMC/E44/DDM system. However, the SB model showed a relatively bad agreement with experimental data of E44/DDM system. AnE variable autocatalytic kinetic model was proposed to describe the curing process of E44/DDM system due to the obvious change of activation energy and the model parameters calculated with the Levenberg-Marquardt method. Compared with the SB model, this model showed a better agreement with the experimental data of E44/DDM system. The results of the research provide theoretical basis for

  5. Optimizing calcium selective fluorimetric nanospheres.

    Science.gov (United States)

    Kisiel, Anna; Kłucińska, Katarzyna; Gniadek, Marianna; Maksymiuk, Krzysztof; Michalska, Agata

    2015-11-01

    Recently it was shown that optical nanosensors based on alternating polymers e.g. poly(maleic anhydride-alt-1-octadecene) were characterized by a linear dependence of emission intensity on logarithm of concentration over a few of orders of magnitude range. In this work we focus on the material used to prepare calcium selective nanosensors. It is shown that alternating polymer nanosensors offer competitive performance in the absence of calcium ionophore, due to interaction of the nanospheres building blocks with analyte ions. The emission increase corresponds to increase of calcium ions contents in the sample within the range from 10(-4) to 10(-1) M. Further improvement in sensitivity (from 10(-6) to 10(-1) M) and selectivity can be achieved by incorporating calcium ionophore in the nanospheres. The optimal results were obtained for core-shell nanospheres, where the core was prepared from poly(styrene-co-maleic anhydride) and the outer layer from poly(maleic anhydride-alt-1-octadecene). Thus obtained chemosensors were showing linear dependence of emission on logarithm of calcium ions concentration within the range from 10(-7) to 10(-1) M. PMID:26452839

  6. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    International Nuclear Information System (INIS)

    By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca9Sr(PO4)6(OH)2 - CaSr9(PO4)6(OH)2. The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice

  7. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    OpenAIRE

    Ueda, Yukari; Taira, Zenei

    2013-01-01

    We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 mg/kg, and is not affected by anions. Results after oral calcium administration of 150 mg/kg showed that the intes...

  8. Effect of solute concentration on fibroin regulated biomineralization of calcium phosphate

    International Nuclear Information System (INIS)

    In this paper we used UV/Visible method to study the effect of solute concentration on fibroin regulated biomineralization of calcium phosphate. During the reaction process, ultraviolet-visible spectrophotometer was used to track the extinction in the reaction solution. It is found that kinetics of the biomineralization can be strongly affected by the presence of fibroin. Fibroin with higher concentration has more positive effect on the biomineralization process. Under the appropriate reaction conditions, wave crest and wave trough appear in the kinetic curves of fibroin biomineralization. The wave crest and wave trough phenomenon is mainly related with the process of phase separation. X-ray Diffraction (XRD) result shows the calcium phosphate before the wave trough is mainly amorphous calcium phosphate, while after the wave trough crystal of hydroxyapatite (HA) and brushite (DCPD) are the mainly ingredients

  9. Downregulation of CD44 reduces doxorubicin resistance of CD44+CD24- breast cancer cells

    Directory of Open Access Journals (Sweden)

    Phuc PV

    2011-06-01

    Full Text Available Pham Van Phuc, Phan Lu Chinh Nhan, Truong Hai Nhung, Nguyen Thanh Tam, Nguyen Minh Hoang, Vuong Gia Tue, Duong Thanh Thuy, Phan Kim NgocLaboratory of Stem Cell Research and Application, University of Science, Vietnam National University, Ho Chi Minh, VietnamBackground: Cells within breast cancer stem cell populations have been confirmed to have a CD44+CD24- phenotype. Strong expression of CD44 plays a critical role in numerous types of human cancers. CD44 is involved in cell differentiation, adhesion, and metastasis of cancer cells.Methods: In this study, we reduced CD44 expression in CD44+CD24- breast cancer stem cells and investigated their sensitivity to an antitumor drug. The CD44+CD24- breast cancer stem cells were isolated from breast tumors; CD44 expression was downregulated with siRNAs followed by treatment with different concentrations of the antitumor drug.Results: The proliferation of CD44 downregulated CD44+CD24- breast cancer stem cells was decreased after drug treatment. We noticed treated cells were more sensitive to doxorubicin, even at low doses, compared with the control groups.Conclusions: It would appear that expression of CD44 is integral among the CD44+CD24- cell population. Reducing the expression level of CD44, combined with doxorubicin treatment, yields promising results for eradicating breast cancer stem cells in vitro. This study opens a new direction in treating breast cancer through gene therapy in conjunction with chemotherapy.Keywords: antitumor drugs, breast cancer stem cells, CD44, CD44+CD24- cells, doxorubicin

  10. Effect of calcium chloride addition on ice cream structure and quality.

    Science.gov (United States)

    Costa, F F; Resende, J V; Abreu, L R; Goff, H D

    2008-06-01

    The influence of calcium fortification by the addition of calcium chloride on quality parameters of ice cream based on physical properties was investigated, as was the effect of kappa-carrageenan at modifying the effects of this calcium fortification. Four ice cream mixes of conventional composition, with added kappa-carrageenan (0 or 0.025%) and added calcium chloride (0 or 4.4 g L(-1) = 40 mM of added Ca(2+)), were prepared. Modulated temperature-differential scanning calorimetry was used to investigate the effect of calcium chloride on the nucleation temperature, enthalpy of melting, and freezing point depression. The protein composition of 15.4% (wt/wt) reconstituted skim milk powder solutions with or without 4.4 g L(-1) added CaCl(2) and in the supernatant after ultracentrifugation was determined. Fat particle size distributions in ice cream were characterized by light scattering. Ice crystal sizes before and after temperature cycling were determined by cold-stage light microscopy. The results demonstrated that the addition of calcium chloride led to a substantial increase in ice crystal sizes and in fat partial coalescence, which were exacerbated by the addition of kappa-carrageenan. These results can be explained by the interaction between Ca(2+) ions and casein micelles, rather than any effects on freezing point depression. The calcium ions led to a more compact micelle, less serum beta-casein, and high fat destabilization, all of which would be expected to reduce macromolecular structure and volume occupancy in the unfrozen phase, which led to increased rates of ice recrystallization. PMID:18487638

  11. Intestinal absorption of calcium from foodstuffs as compared to a pharmaceutical preparation.

    Science.gov (United States)

    Werner, E; Hansen, Ch; Roth, P; Kaltwasser, J P

    1999-01-01

    Only few data are available on intestinal calcium absorption from foodstuffs and composite meals in humans. The aim of the study was to compare intraindividually the calcium absorption from milk and from a breakfast with that from a pharmaceutical calcium preparation of equal calcium content. In 8 healthy volunteers between 44 and 58 years of age, the intestinal calcium absorption was measured in randomized order applying the double isotope technique from: (1) 500ml of fresh milk (equivalent to 620mg Ca), (2) a test meal composed of 250 g curd, 150g yoghurt, 3 slices pineapple, 2 breakfast rolls, 2 cups of coffee, 10g of coffee cream, 20g butter, 50g jam and 20g honey (equivalent to 580mg Ca), and (3) a lactogluconate effervescent tablet (equivalent to 500mgCa). All test doses were given on an empty stomach and labelled with 20mg 44Ca. Simultaneously, 5mg 42Ca in a sterile isotonic solution were injected intravenously. The mean values of the absorbed fractions are 24.0% +/- 5.4% (mean +/-SD), 17.9% +/- 7.1%, and 28.7% +/- 9.1% for the milk, for the meal and for the tablet respectively. The data show that less calcium is absorbed from foodstuffs as compared to a preparation of optimal bioavailability. But in this study only the difference between absorption from the milk and from the meal was statistically significant. Therefore, it is possible to obtain a sufficient calcium supply of the human body also by properly selected foodstuffs. PMID:10902536

  12. Calcium release-activated calcium current in rat mast cells.

    Science.gov (United States)

    Hoth, M; Penner, R

    1993-06-01

    1. Whole-cell patch clamp recordings of membrane currents and fura-2 measurements of free intracellular calcium concentration ([Ca2+]i) were used to study the biophysical properties of a calcium current activated by depletion of intracellular calcium stores in rat peritoneal mast cells. 2. Calcium influx through an inward calcium release-activated calcium current (ICRAC) was induced by three independent mechanisms that result in store depletion: intracellular infusion of inositol 1,4,5-trisphosphate (InsP3) or extracellular application of ionomycin (active depletion), and intracellular infusion of calcium chelators (ethylene glycol bis-N,N,N',N'-tetraacetic acid (EGTA) or 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)) to prevent reuptake of leaked-out calcium into the stores (passive depletion). 3. The activation of ICRAC induced by active store depletion has a short delay (4-14 s) following intracellular infusion of InsP3 or extracellular application of ionomycin. It has a monoexponential time course with a time constant of 20-30 s and, depending on the complementary Ca2+ buffer, a mean normalized amplitude (at 0 mV) of 0.6 pA pF-1 (with EGTA) and 1.1 pA pF-1 (with BAPTA). 4. After full activation of ICRAC by InsP3 in the presence of EGTA (10 mM), hyperpolarizing pulses to -100 mV induced an instantaneous inward current that decayed by 64% within 50 ms. This inactivation is probably mediated by [Ca2+]i, since the decrease of inward current in the presence of the fast Ca2+ buffer BAPTA (10 mM) was only 30%. 5. The amplitude of ICRAC was dependent on the extracellular Ca2+ concentration with an apparent dissociation constant (KD) of 3.3 mM. Inward currents were nonsaturating up to -200 mV. 6. The selectivity of ICRAC for Ca2+ was assessed by using fura-2 as the dominant intracellular buffer (at a concentration of 2 mM) and relating the absolute changes in the calcium-sensitive fluorescence (390 nm excitation) with the calcium current integral

  13. Calcium phosphate in catheter encrustation.

    Science.gov (United States)

    Cox, A J; Harries, J E; Hukins, D W; Kennedy, A P; Sutton, T M

    1987-02-01

    Encrusted catheters from nine female patients were the source of samples of deposits which were examined by X-ray diffraction, atomic absorption spectroscopy, infra-red spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. In eight samples the only crystalline phase which could be clearly distinguished by X-ray diffraction was ammonium magnesium orthophosphate hexahydrate, NH4MgPO4 X 6H2O, which occurs naturally as the mineral struvite. However, atomic absorption spectroscopy revealed an appreciable concentration of calcium in all samples. Calcium phosphates have previously been detected in catheter deposits. Infra-red and EXAFS spectra were consistent with the calcium phosphate being present as a poorly crystalline hydroxyapatite. Thus the deposits appear to consist of a mixture of crystalline struvite and a form of hydroxyapatite which is not fully crystalline. PMID:3030487

  14. African Studies Abstracts Online: number 44, 2013

    OpenAIRE

    African Studies Centre

    2013-01-01

    ASA Online provides a quarterly overview of journal articles and edited works on Africa in the field of the social sciences and the humanities available in the ASC library. Issue 44 (2013). African Studies Centre, Leiden.

  15. 44 CFR 10.11 - Environmental information.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Environmental information. 10... Environmental information. Interested persons may contact the Environmental Officer or the Regional Administrator for information regarding FEMA's compliance with NEPA....

  16. 44 CFR 204.42 - Eligible costs.

    Science.gov (United States)

    2010-10-01

    ... under State law and procedure and complying with 44 CFR part 13. (b) Equipment and supplies. Eligible... the firefighting effort or activities. This includes minimal repairs to bulldozer lines, camps,...

  17. The effect of variable calcium and very low calcium diets on human calcium metabolism. Ph.D. Thesis. Final Report

    Science.gov (United States)

    Chu, J.

    1971-01-01

    The effects of a very low calcium diet, with variable high and low protein intake, on the dynamics of calcium metabolism and the mechanism of calciuretics, are examined. The experiment, using male subjects, was designed to study the role of intestinal calcium absorption on urinary calcium excretion, and the rate of production of endogeneously secreted calcium in the gastrointestinal tract. The study showed an average of 70% fractional absorption rate during very low calcium intake, and that a decrease in renal tubular reabsorption of calcium is responsible for calciuretic effects of high protein intake. The study also indicates that there is a tendency to develop osteoporosis after long periods of low calcium intake, especially with a concurrent high protein intake.

  18. Tumoral calcium pyrophosphate deposition disease

    International Nuclear Information System (INIS)

    A report of two patients in which a soft tissue mass, initially regarded as a malignant tumor, was shown to be the result of calcium pyrophosphate deposition disease. The first case, a woman aged 71 years, presented with a mass involving the right fifth finger. In the second case, also a women aged 71 years, the lesion involved the tissues adjacent to the right hip. Each lesion consisted of a mass of highly cellular tissue containing deposits of calcium pyrophosphate dihydrate crystals. The clinical, radiological, and pathological features of the two cases are compared with those of seven similar cases reported in the literature. (orig.)

  19. Synthesis and Formation Mechanisms of Calcium Ferrite Compounds

    Institute of Scientific and Technical Information of China (English)

    Hesham I. Saleh

    2004-01-01

    Calcium ferrite compounds were prepared using calcium nitrate and iron nitrate with different molar ratios, 1:1, 0.5:1, and 1:0.5,respectively. The reactions of formation were investigated at different temperatures following the differential thermal analysis (DTA) results. Calcium ferrite compounds are CaFeO3, Ca2FeO3.5, Ca2Fe2O5, CaFe2O4, CaFe4O7, Ca7.2Fe0.8Fe30O53,Ca3Fe15O25, Ca4Fe14O25, and Ca4Fe9O17. Other reactive species of calcium nitrate are still present after firing at 450℃.Compounds were characterized using X-ray diffraction (XRD), DTA, TG, magnetic susceptibility, infrared spectra and scanning electron microscope (SEM). It is concluded that the formation mechanism of Ca-ferrite compounds depends mainly on the valency of iron cations which in role depends on its molar ratio and the existing atmosphere.

  20. Immobilization of calcium oxide solid reactant on a yttria fabric and thermodynamic analysis of UT-3 thermochemical hydrogen production cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Man Su [Mechanical and Aerospace Engineering, University of Florida, P.O. Box 116300, Gainesville, FL 32611 (United States); Goswami, D. Yogi; Stefanakos, Elias K. [Clean Energy Research Center, University of South Florida, 4202 E Fowler Avenue Tampa, FL 33620 (United States)

    2009-01-15

    UT-3 cycle has been considered as one of the most promising thermochemical processes for hydrogen production. In order to make the cycle practical, however, the solid reactants in the cyclic reactions must have adequate lifespan and better kinetics. In this paper, hydrolysis reaction of calcium bromide, the slowest process in the cycle, was investigated theoretically and experimentally. A new type of calcium oxide reactant was fabricated by dispersing and fixing it on a yttria fabric via a comparatively straightforward and inexpensive immobilization process. The characteristics and cyclic performance of the prepared fabric samples were evaluated and compared with the conventional calcium oxide pellets. It was shown that the calcium oxide immobilized on the yttria fabric had continuous higher reactivity and comparable hydrolysis rate compared with the conventional calcium oxide pellets. A theoretical analysis of the thermodynamic cycle was also conducted. The effect of excess steam on the equilibrium conversion was significant; however, the reaction temperature was limited due to the melting point of calcium bromide. By continuously removing the product gas, the conversion in the hydrolysis reaction which is the slowest reaction in the cycle could be completed theoretically. This hypothesis was found to be true based on the experimental tests. (author)

  1. The Incredible, Embryological Egg: Calcium and Strontium Isotopes Recapitulate Ontogeny

    Science.gov (United States)

    Gordon, G. W.; Skulan, J. L.

    2011-12-01

    Embryological development reflects evolutionary history. Understanding the processes of fetal growth is important for curing human birth defects and predicting damage to ecosystems from environmental insults. Tracing enzymatic and hormonal gradients during development, and correlating them to genetic cues dominate modern embryology. Previous work done tracing the mass transfer of elements has generally been limited to isotope spikes in vitro. Natural mass-dependent Ca and Sr isotopic ratios and radiogenic Sr isotopes have the potential to reveal both source and biochemical mechanism information about processes in vivo, but have not previously been extensively explored. The process when a hen lays a fertilized egg that becomes a chick includes formation and dissolution of calcium phosphate (bone) and calcium carbonate (shell). Skulan and DePaolo (1999) showed that chickens have 2% δ44/42Ca between a hen's bones and an egg white; this span represents more than 80% of the entire range of natural Ca isotope variation and illustrates there is significant variation to investigate. A striking feature of archosaurian development that also occurs in many mammals, including humans, is mass transfer of calcium from mother to embryo. The yolk of the domestic hen matures over 7-9 days, but the albumen, shell membranes and shell form in less than 20 hours. Domestic laying hens are at the physiological limit of egg production and selective breeding is no longer an effective method of increasing egg production. 60-75% of the shell's ~1.5 g of calcium comes from dietary sources, while 25-40% comes from the hen's medullary bone. Medullary bone is spicules formed in the marrow of long bones, and is a store of dietary calcium rapidly available for eggshell secretion. During in ovo development, the embryo's skeleton is formed from calcium in the yolk and by bulk dissolution of the eggshell's inner aspect via carbonic anhydrase in a process that has an effect on bone density similar to

  2. Complex formation ions calcium with macromolecules pectin

    International Nuclear Information System (INIS)

    In clause the mechanism of sorption of ions of calcium by macromolecules of pectin is opened. Is shown, that the linkage of ions of calcium descends on acid bunches of pectin, and process carries cooperative character

  3. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Devkanya Dutta

    2000-12-01

    Activation of receptors coupled to the phospholipase C/IP3 signalling pathway results in a rapid release of calcium from its intracellular stores, eventually leading to depletion of these stores. Calcium store depletion triggers an influx of extracellular calcium across the plasma membrane, a mechanism known as the store-operated calcium entry or capacitative calcium entry. Capacitative calcium current plays a key role in replenishing calcium stores and activating various physiological processes. Despite considerable efforts, very little is known about the molecular nature of the capacitative channel and the signalling pathway that activates it. This review summarizes our current knowledge about store operated calcium entry and suggests possible hypotheses for its mode of activation.

  4. Dairy Dilemma: Are You Getting Enough Calcium?

    Science.gov (United States)

    ... Dairy Dilemma Dairy Dilemma Are You Getting Enough Calcium? You may be avoiding dairy products because of ... But dairy products are a major source of calcium, vitamin D and other nutrients that are important ...

  5. Calcium, vitamin D, and your bones

    Science.gov (United States)

    ... can break easily, even without an obvious injury. Vitamin D helps your body absorb calcium. Eat foods that provide the right amounts of calcium, vitamin D, and protein. This kind of diet will give ...

  6. Biodiesel production through transesterification over natural calciums

    Energy Technology Data Exchange (ETDEWEB)

    Ngamcharussrivichai, Chawalit [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Phyathai Rd., Patumwan, Bangkok 10330 (Thailand); Center of Excellence for Petroleum, Petrochemicals and Advanced Materials, Chulalongkorn University, Phyathai Rd., Patumwan, Bangkok 10330 (Thailand); Nunthasanti, Pramwit; Tanachai, Sithikorn; Bunyakiat, Kunchana [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Phyathai Rd., Patumwan, Bangkok 10330 (Thailand)

    2010-11-15

    Transesterification of palm kernel oil (PKO) with methanol over various natural calciums, including limestone calcite, cuttlebone, dolomite, hydroxyapatite, and dicalcium phosphate, has been investigated at 60 C and 1 atm. The study showed that dolomite, mainly consisting of CaCO{sub 3} and MgCO{sub 3}, is the most active catalyst. The calcination temperature largely affected the physicochemical properties, as evidenced by N{sub 2} adsorption-desorption measurement, TGA, SEM and XRD, and the transesterification performance of the resultant catalysts. It was found that the calcination of dolomite at 800 C resulted in a highly active mixed oxide. CaO was suggested to be the catalytically active site responsible for the methyl ester formation. Under the suitable reaction conditions, the amount of dolomite calcined at 800 C = 6 wt.% based on the weight of oil, the methanol/oil molar ratio = 30, and the reaction time = 3 h, the methyl ester content of 98.0% can be achieved. The calcined dolomite can be reused many times. The analyses of some important fuel properties indicated that the biodiesel produced had the properties that meet the standard of biodiesel and diesel fuel issued by the Department of Energy Business, Ministry of Energy, Thailand. (author)

  7. Calcium channel blockers and Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Yi Tan; Yulin Deng; Hong Qing

    2012-01-01

    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofi-brillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers in-volved in Alzheimer's disease therapy.

  8. Calcium channel blockers and Alzheimer's disease★

    OpenAIRE

    Tan, Yi; Deng, Yulin; Qing, Hong

    2012-01-01

    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofibrillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers involved in...

  9. Photoelectron spectroscopy investigation of the C60/calcium interface

    Energy Technology Data Exchange (ETDEWEB)

    Wetzstein, Holger; Schoell, Achim; Reinert, Friedrich [Experimental Physics VII, Julius-Maximilians-University of Wuerzburg, D-97074 Wuerzburg (Germany); Bunandar, Darius [Department of Physics, University of Texas at Austin, Austin, TX 78712-0264 (United States); Schafferhans, Julia; Deibel, Carsten [Experimental Physics VI, Julius-Maximilians-University of Wuerzburg, D-97074 Wuerzburg (Germany)

    2011-07-01

    Device lifetime is a crucial point for organic solar cells. Therefore it is important to understand the degradation mechanisms as well as their consequence on the performance of these photovoltaic devices. We observed a characteristic S-shape in the I/V-curves of P3HT/PCBM-bulk heterojunction cells with calcium contacts. A tentative origin of this behavior is a reaction of the calcium with oxygen, which leads to alterations in the regime of the anode interface. To shed more light on this issue we investigated the electronic structure of the Ca/C{sub 60} interface, which serves as a model for the PCBM/Ca contact. X-ray (XPS) and ultra-violet photoelectron spectroscopy (UPS) measurements were performed on C{sub 60} layers adsorbed on epitaxially grown Calcium as well as on Ca deposited on C{sub 60}. In both cases, the data clearly show the formation of an interface state due to the charge transfer from the Ca into the C{sub 60}, which is an indication for a chemical reaction. Moreover, we studied the effect of oxygen exposure on the interfacial chemical and electronic structure under conditions comparable to the conditions during device operation.

  10. Teaching Calcium-Induced Calcium Release in Cardiomyocytes Using a Classic Paper by Fabiato

    Science.gov (United States)

    Liang, Willmann

    2008-01-01

    This teaching paper utilizes the materials presented by Dr. Fabiato in his review article entitled "Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum." In the review, supporting evidence of calcium-induced calcium release (CICR) is presented. Data concerning potential objections to the CICR theory are discussed as well. In…

  11. Hydrogen Evolution on Supported Incomplete Cubane-type [Mo3S4](4+) Electrocatalysts

    DEFF Research Database (Denmark)

    Jaramillo, Thomas; Bonde, Jacob Lindner; Zhang, Jingdong;

    2008-01-01

    Electrocatalytic properties of biomimetic supported incomplete cubane-type [Mo3S4](4+) clusters are investigated. The activity toward the hydrogen evolution reaction (HER) is evaluated on both a high surface area gas diffusion electrode in a membrane electrode assembly and on highly orientated...

  12. Electrophysical properties of calcium orthovanadate

    International Nuclear Information System (INIS)

    The electron conductivity, dielectric permeability and magnetic susceptibility of calcium orthovanadate are studied. It is shown that structural transformations bring about changes in the nature of electrophysical properties of Ca3(VO4)2 and cause the charge redistribution in VO43- anion groups

  13. The Validity and Reliability of the Turkish Version of the Obsessive Beliefs Questionnaire-44 (OBQ-44)

    OpenAIRE

    Murat BOYSAN; Lütfullah BEŞİROĞLU; Nuralay ÇETİNKAYA; Atli, Abdullah; Adem AYDIN

    2010-01-01

    Objective: Cognitive factors have a central place in the etiology and persistenceof obsessive-compulsive disorder (OCD). The aim of the study was to evaluatepsychometric properties of the Turkish version of the ObsessiveBeliefs Questionnaire-44 (OBQ-44). Original factor structure of the OBQ-44 anddiscrimination characteristic of the instrument between OCD patients andnonclinical population were evaluated extensively in Turkish sample.Methods: Data were collected from 175 healthy subjects and ...

  14. 48 CFR 53.301-44 - Standard Form 44, Purchase Order-Invoice-Voucher.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Standard Form 44, Purchase Order-Invoice-Voucher. 53.301-44 Section 53.301-44 Federal Acquisition Regulations System FEDERAL..., Purchase Order—Invoice—Voucher. EC01MY91.021 EC01MY91.022 EC01MY91.023 EC01MY91.024...

  15. Butyl acetate synthesis using immobilized lipase in calcium alginate beads

    International Nuclear Information System (INIS)

    The esterification reaction of acetic acid and n-butanol using immobilized lipase encapsulated in calcium alginate beads (Lipase - CAB) and in chitosan coated calcium alginate beads (Lipase-CCAB) in n-hexane under mild reaction conditions were studied. Effects of temperature and substrate concentration (acetic acid and n-butanol) using Lipase - CAB, Lipase - CCAB and free lipase on the esterification reaction and their thermal stability towards esterification reaction were investigated. Results of temperature studies showed that the butyl acetate conversion increased with increase of temperature and reached the highest yield of about 70% around 50 degree Celsius for both immobilized systems but the yield of product catalyzed by free enzyme decreased as temperature was increased. Thermal stabilities studies showed that the Lipase-CCAB and Lipase-CAB were stable throughout the temperature range of 30-60 degree Celsius. However, free lipase became less stable at temperatures higher than 50 degree Celsius. The substrates, n-butanol and acetic acid exerted different effects on the esterification reaction and the reaction was favoured by higher acetic acid concentration than butanol. Kinetics parameters, Km and Vmax values for both substrates and the specific activities of the three enzyme system were also determined. The beads morphology was examined using SEM. Batch-wise operational stability studies for both immobilized systems demonstrated that the immobilized lipase performed better in the batch wise reactor system than the continuous bioreactor system and that the immobilized lipase remained active for at least 5 cycles of batch wise esterification reactions. (author)

  16. 21 CFR 582.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  17. 21 CFR 182.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  18. 21 CFR 582.5217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.5217 Section 582.5217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  19. 21 CFR 582.1191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium carbonate. 582.1191 Section 582.1191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  20. 21 CFR 582.5191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium carbonate. 582.5191 Section 582.5191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  1. 21 CFR 73.1070 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Calcium carbonate. 73.1070 Section 73.1070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1070 Calcium carbonate. (a) Identity. (1) The color additive calcium carbonate is a fine,...

  2. 21 CFR 582.1205 - Calcium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  3. 21 CFR 182.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 182.2227 Section 182.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Anticaking Agents § 182.2227 Calcium silicate. (a) Product. Calcium silicate....

  4. 21 CFR 582.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 582.2227 Section 582.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c)...

  5. Calcium dynamics in vascular smooth muscle

    OpenAIRE

    Amberg, Gregory C.; Navedo, Manuel F.

    2013-01-01

    Smooth muscle cells are ultimately responsible for determining vascular luminal diameter and blood flow. Dynamic changes in intracellular calcium are a critical mechanism regulating vascular smooth muscle contractility. Processes influencing intracellular calcium are therefore important regulators of vascular function with physiological and pathophysiological consequences. In this review we discuss the major dynamic calcium signals identified and characterized in vascular smooth muscle cells....

  6. Lactulose stimulates calcium absorption in postmenopausal women

    NARCIS (Netherlands)

    Heuvel, E.G.H.M. van den; Muijs, T.; Dokkum, W. van; Schaafsma, G.

    1999-01-01

    Animal studies have indicated that calcium absorption is increased by lactulose, a synthetic disaccharide. Therefore, the influence of lactulose on calcium absorption was measured in postmenopausal women who may benefit from the possible enhancing effect of lactulose on calcium absorption. Twelve po

  7. Half-life of {sup 44}Ti

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Kutschera, W.; Castagnoli, G. [Instituto di Cosmogeofisica, Torino (Italy); Paul, M. [Hebrew Univ., Jerusalem (Israel)

    1995-08-01

    The measurement of the {sup 44}Ti half-life, started 3 years ago, is still continuing. The goal of this measurement is to determine the half-life of {sup 44}Ti, which is {approximately}52 y, to a precision of {approximately}5%. An accurate value of this half-life is of interest to cosmologists who need it to determine the production of heavy elements in supernova. Three sets of samples - a pure 200-nCi {sup 44}Ti sample, a pure 300-nCi {sup 60}Co source, and a mixed {sup 44}Ti-{sup 60}Co source of similar strength - were prepared and their spectra are being measured with Ge spectrometers at Argonne, Torino and Jerusalem. Each sample is counted for a period of 2 days, at approximate intervals of 4 months. The room background is also measured for the same length of time. We hope to start data analysis at the end of summer and obtain a value for the {sup 44}Ti half-life.

  8. Sodium/Calcium Exchangers Selectively Regulate Calcium Signaling in Mouse Taste Receptor Cells

    OpenAIRE

    Szebenyi, Steven A.; Laskowski, Agnieszka I.; Medler, Kathryn F.

    2010-01-01

    Taste cells use multiple signaling mechanisms to generate appropriate cellular responses to discrete taste stimuli. Some taste stimuli activate G protein coupled receptors (GPCRs) that cause calcium release from intracellular stores while other stimuli depolarize taste cells to cause calcium influx through voltage-gated calcium channels (VGCCs). While the signaling mechanisms that initiate calcium signals have been described in taste cells, the calcium clearance mechanisms (CCMs) that contrib...

  9. Calcium electroporation in three cell lines; a comparison of bleomycin and calcium, calcium compounds, and pulsing conditions

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gissel, Hanne; Hojman, Pernille;

    2013-01-01

    BACKGROUND: Electroporation with calcium (calcium electroporation) can induce ATP depletion-associated cellular death. In the clinical setting, the cytotoxic drug bleomycin is currently used with electroporation (electrochemotherapy) for palliative treatment of tumors. Calcium electroporation...... offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium...... electroporation and electrochemotherapy. METHODS: The effects of calcium electroporation and bleomycin electroporation (alone or in combination) were compared in three different cell lines (DC-3F, transformed Chinese hamster lung fibroblast; K-562, human leukemia; and murine Lewis Lung Carcinoma). Furthermore...

  10. Association of Calcium-Sensing Receptor (CASR rs 1801725 with Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Fateme Rostami

    2012-07-01

    Full Text Available Background: Calcium induces apoptosis in intestinal epithelial cells and subsequently prevents colorectal cancer through ion calcium receptor. Calcium-sensing receptor mutation reduces the expression of this receptor, and subsequently in reduces calcium transportation. Many studies have shown that Calcium-sensing receptor gene polymorphism may increase the risk of colorectal cancer. The purpose of this study is to assess the prevalence of calcium-sensing receptor polymorphisms (rs 1801725 in Iran society and to examine the role of this polymorphism in the increased risk of colorectal cancer (CRC.Materials and Methods: The research was a case-control study. 105 patients with colorectal cancer and 105 controls were randomly studied using polymerase chain reaction and restriction fragment length polymorphism. χ2 test and software 16- SPSS were used for statistical analysis.Results: In patient samples, the frequency of the genotypes TT, GT, GG in gene CASR rs 1801725 was respectively 64.8, 32.4, and 2.9 and the frequency of this polymorphism in control samples was respectively 51.2, 45.7, and 2.9. Frequency of allele G in patient samples was 0/48 and frequency of allele T was 0.25. In addition, Frequency of allele G in control samples was 0.74 and Frequency of allele T was calculated 0.19.Conclusion: The results show that calcium-sensing receptor variant (1801725 rs is not associated with increased risk of colorectal cancer.

  11. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    OpenAIRE

    Zenei Taira, Zenei

    2013-01-01

    Yukari Ueda, Zenei TairaFaculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, JapanAbstract: We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 ...

  12. Dual role of CD44 isoforms in ampullary adenocarcinoma: CD44s predicts poor prognosis in early cancer and CD44ν is an indicator for recurrence in advanced cancer

    OpenAIRE

    Wu, Cheng-Lin; Chao, Ying-Jui; Yang, Ta-Ming; Chen, Yi-Ling; Chang, Kung-Chao; HSU, HUI-PING; Shan, Yan-Shen; Lai, Ming-Derg

    2015-01-01

    Background Although postoperative adjuvant chemoradiotherapies prevent recurrence for some patients with ampullary cancer, the recurrence rate is as high as 29 % in patients with stage I cancer. In an effort to identify predictors of recurrence in patients with ampullary adenocarcinoma, we investigated the clinical value of assessing standard and variant forms of CD44. Methods Immunohistochemistry staining and reverse-transcription polymerase chain reaction (RT-PCR) was used to detect standar...

  13. ACTION OF SILICATO OF CALCIUM AND MAGNESIUM IN THE REDUCTION Cercospora

    Directory of Open Access Journals (Sweden)

    Franciane Diniz Cogo

    2011-07-01

    Full Text Available The aim of this study was to evaluate the response of coffee plants (Coffea arabica Catuaí IAC-44 with different doses of calcium silicate and magnesium in relation to incidence of Cercospora spot coffeicola and plant growth. The experiment was conducted in nursery seedling production of coffee from the Federal Institute of Southern Minas Gerais, Campus Machado, MG randomized blocks with five replications and the treatment used a source of silicon, calcium silicate and magnesium in doses - 0 (control, 75, 150, 225 300 g/m2. The application of silicon in the soil causes the reduction to Cercospora coffeicola. The application of calcium silicate and magnesium affect the growth characteristics and was effective in inducing gray leaf spot, via ground coffee seedlings in nurseries.

  14. Experimental research on combustion fluorine retention using calcium-based sorbets during coal combustion (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    QI Qing-jie; LIN Zhi-yan; LIU Jian-zhong; WU Xian; ZHOU Jun-hu; CEN Ke-fa

    2008-01-01

    In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermo-dynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention.

  15. Effects on anionic salts in a pre-partum dairy ration on calcium metabolism

    OpenAIRE

    C.J. Van Dijk; D.C. Lourens

    2001-01-01

    The effects of anionic salts in the transition diet on serum and urine calcium at calving and on peripartal health, subsequent milk production and fertility performance were studied in a well-managed, high-producing Friesland dairy herd. Over a period of a year, approximately 21 days before the expected date of calving, 28 pre-partum heifers and 44 multiparous dry cows were randomly allocated within parity to 1 of 2 transition diets, designated control and experimental anionic diets. The anio...

  16. Zinc recovery from spent ZnO catalyst by carbon in the presence of calcium carbonate

    Science.gov (United States)

    Hsu, Hua-Ching; Lin, Chun-I.; Chen, Hsi-Kuei

    2004-02-01

    Zinc recovery from the spent zinc oxide catalyst by carbon in the presence of calcium carbonate was studied using an X-ray diffractometer (XRD), an atomic absorption spectrometer (AAS), and a scanning electron microscope (SEM). The spent zinc oxide catalyst was determined to be composed of 87.5 wt pct zinc oxide and 3.1 wt pct zinc sulfide. The results of X-ray diffractometry revealed that calcium carbonate decomposed to calcium oxide and carbon dioxide; zinc oxide and zinc sulfide were reduced to zinc vapor and carbon monoxide evolving from solid sample; and sulfur content was scavenged as calcium sulfide remained in the solid. Steps involved in this reaction system were summarized to explain the overall reaction. The experimental results of atomic absorption spectrometry showed that the initial rate of zinc recovery and final zinc recovery can be increased by increasing either the sample height, the reaction temperature or the initial bulk density. Furthermore, they were found to increase with decrease in either the argon flow rate, the molar ratio of Zntotal/C, the molar ratio of Zntotal/CaCO3, the grain size of the spent catalyst, the agglomerate size of carbon, or the agglomerate size of calcium carbonate. Empirical expressions of the initial rate of zinc recovery and final zinc recovery have been determined.

  17. Calcium signals and calcium channels in osteoblastic cells

    Science.gov (United States)

    Duncan, R. L.; Akanbi, K. A.; Farach-Carson, M. C.

    1998-01-01

    Calcium (Ca2+) channels are present in non-excitable as well as in excitable cells. In bone cells of the osteoblast lineage, Ca2+ channels play fundamental roles in cellular responses to external stimuli including both mechanical forces and hormonal signals. They are also proposed to modulate paracrine signaling between bone-forming osteoblasts and bone-resorbing osteoclasts at local sites of bone remodeling. Calcium signals are characterized by transient increases in intracellular Ca2+ levels that are associated with activation of intracellular signaling pathways that control cell behavior and phenotype, including patterns of gene expression. Development of Ca2+ signals is a tightly regulated cellular process that involves the concerted actions of plasma membrane and intracellular Ca2+ channels, along with Ca2+ pumps and exchangers. This review summarizes the current state of knowledge concerning the structure, function, and role of Ca2+ channels and Ca2+ signals in bone cells, focusing on the osteoblast.

  18. Computational study of a calcium release-activated calcium channel

    Science.gov (United States)

    Talukdar, Keka; Shantappa, Anil

    2016-05-01

    The naturally occurring proteins that form hole in membrane are commonly known as ion channels. They play multiple roles in many important biological processes. Deletion or alteration of these channels often leads to serious problems in the physiological processes as it controls the flow of ions through it. The proper maintenance of the flow of ions, in turn, is required for normal health. Here we have investigated the behavior of a calcium release-activated calcium ion channel with pdb entry 4HKR in Drosophila Melanogaster. The equilibrium energy as well as molecular dynamics simulation is performed first. The protein is subjected to molecular dynamics simulation to find their energy minimized value. Simulation of the protein in the environment of water and ions has given us important results too. The solvation energy is also found using Charmm potential.

  19. Developing a Clinically Useful Calcium Isotope Biomarker

    Science.gov (United States)

    Romaniello, Stephen J.; Anbar, Ariel D.; Gordon, Gwyneth W.; Skulan, Joseph L.; Smith, Scott M.; Zwart, Sara R.; Monge, Jorge; Fonseca, Rafael

    2016-01-01

    Naturally-occurring Ca is mixture of six isotopes Ca-40, Ca-42, Ca-43, Ca-44, Ca-46, Ca-48). Biological reaction rates and equilibrium constants depend slightly, but measurably, on atomic mass, causing the relative abundances of Ca isotopes to vary between different tissues. During bone formation, light isotopes of Ca are preferentially incorporated into bone, leaving soft tissue depleted in light isotopes. In contrast, bone resorption exhibits no isotopic preference, and thus transfers the light isotope signature of bone back to soft tissue. This balance makes the Ca isotope composition of soft tissue (e.g. serum, urine) a highly sensitive, quantitative tracer for whole-body bone mineral balance (BMB).

  20. Application of a novel calcium looping process for production of heat and carbon dioxide enrichment of greenhouses

    International Nuclear Information System (INIS)

    Highlights: • The greenhouse calcium looping process was developed by ASPEN Plus simulator. • In this process, the carbonation reaction provides required heat during night time. • The calcination reaction provides required carbon dioxide during day time. • This novel process saves up to 72% energy compared to the fossil fuel burners. • The process thermodynamically attributes to zero emission of carbon dioxide. - Abstract: Greenhouses typically employ conventional burner systems to suffice heat and carbon dioxide required for plant growth. The energy requirement and carbon dioxide emissions from fossil fuel burner are generally high. As an alternative, this paper describes a novel greenhouse calcium looping process which is expected to decrease the energy requirements and associated carbon dioxide emissions. The conceptual design of greenhouse calcium looping process is carried out in the ASPEN Plus v 7.3 simulator. In a greenhouse calcium looping process, the calcination reaction is considered to take place during day time in order to provide the required optimum carbon dioxide between 1000 and 2000 ppm, while the carbonation reaction is occurred during night time to provide required heat. The process simulations carried out in ASPEN indicates that greenhouse calcium looping process theoretically attributes to zero emission of carbon dioxide. Moreover, in a scenario modelling study compared to the conventional natural gas burner system, the heat duty requirements in the greenhouse calcium looping process were found to reduce by as high as 72%

  1. Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: Early fluorapatite formation in a phosphate-containing solution

    OpenAIRE

    Gandolfi, M.G.; Taddei, P.; Siboni, F.; Modena, E.; Ginebra Molins, Maria Pau; Prati, Claudio

    2011-01-01

    Gandolfi MG, Taddei P, Siboni F, Modena E, Ginebra MP, Prati C. Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: early fluorapatite formation in a phosphate-containing solution. International Endodontic Journal, 44, 938–949, 2011. Aim To test the chemical–physical properties and apatite-forming ability of experimental fluoride-doped calcium silicate cements designed to create novel bioactive materials for use in endodontics ...

  2. Substitution of calcium by strontium within selected calcium phosphates

    Science.gov (United States)

    Rokita, E.; Hermes, C.; Nolting, H.-F.; Ryczek, J.

    1993-06-01

    Sr incorporation in the molecules of amorphous calcium phosphate, apatitic tricalcium phosphate, hydroxyapatite, octacalcium phosphate and dicalcium phosphate dihydrate was investigated. The concentration of Sr ranged from 225 to 1010 μ g / g, i.e. it overlapped with the physiological range of Sr concentrations in human bone. The leading experimental technique was extended X-ray absorption fine structure (EXAFS) at the Sr K edge. Results of these studies demonstrated the following: (1) Sr incorporation in the calcium phosphates is compound-dependent, (2) the coordination of incorporated Sr atoms in the Ca-P molecules is similar to that of Ca atoms, but interatomic distances are ≈0.015 nm larger, (3) in apatitic tricalcium phosphate, hydroxyapatite and octacalcium phosphate lattices Sr atoms may occupy selected Ca sites, which was not the case for dicalcium phosphate dihydrate, (4) in the apatite lattice Sr atoms are coordinated by 6 PO 4 tetrahedrals and (5) EXAFS spectra at the K edge of the incorporated Sr may be used to distinguish the structures of amorphous calcium phosphate, dicalcium phosphate dihydrate as well as apatite and its derivatives (apatitic tricalcium phosphate, octacalcium phosphate).

  3. USING CALCIUM CARBONATE WHISKERS AS PAPERMAKING FILLER

    Directory of Open Access Journals (Sweden)

    Xiaoyu Chen

    2011-05-01

    Full Text Available Whiskers, having large length/diameter ratio, are fiber-shaped single crystals. The technical possibility of using calcium carbonate whiskers as papermaking filler to replace conventional powder-like calcium carbonate was investigated. The results showed that it may be feasible to use calcium carbonate whisker as papermaking filler. Compared with conventional precipitated calcium carbonate, calcium carbonate whisker had higher retention efficiency. The use of calcium carbonate whisker also favorably affected the strength properties of paper sheets. A model was proposed to suggest the mechanism for paper strength improvement. The whiskers filled in paper sheets could increase the friction between fibers, thus increasing bonding strength. Moreover, the strength properties of paper were further improved because calcium carbonate whiskers were partly embedded in pulp fiber walls.

  4. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    Directory of Open Access Journals (Sweden)

    Choksi Krishna

    2011-03-01

    Full Text Available The objective of present study is to evaluate the effects of calcium carbonate and calcium gluconate on acute and subacute inflammation and to study their possible interactions with Aspirin. Calcium carbonate (10 mg/kg and calcium gluconate (5 mg/kg were administered individually and also co-administered along with sub therapeutic dose Aspirin (50mg/kg to study their interaction. The inflammation was induced by carrageenan or a foreign body. Both calcium carbonate and calcium gluconate could not show significant anti-inflammatory activity on their own in acute as well as subacute inflammation models. Aspirin at sub-anti-inflammatory dose (50mg/Kg when co-administered along with calcium salts produced the significant anti-inflammatory response which was comparable to anti-inflammatory response of aspirin at therapeutic dose (200mg/Kg. Also co-adminostration minimized the gastro-toxicity of aspirin.

  5. Investigating calcium polyphosphate addition to a conventional calcium phosphate cement for bone-interfacing applications

    Science.gov (United States)

    Krausher, Jennifer Lynn

    Calcium phosphate cements (CPCs) are of great interest in bone regeneration applications because of their biocompatibility and osteoconductivity, and as delivery vehicles for therapeutics; however, delivery applications have been limited by adverse interactions between therapeutics and the cement setting reaction. Amorphous calcium polyphosphate (CPP) yields a biodegradable material with a demonstrated drug delivery capacity following appropriate processing. The incorporation of drug-loaded CPP into a CPC is under consideration as a method of minimizing adverse interactions and extending drug release. This thesis represents the first investigation into the effects of CPP addition on the properties, setting and antibiotic release profile of a conventional apatitic calcium phosphate cement. As-made, gelled and vancomycin-loaded CPP particulate were added to the powder component of a conventional dicalcium phosphate/tetracalcium phosphate CPC. The setting behaviour, set properties and microstructure of the resulting CPP-CPCs were evaluated with setting time testing (Gilmore needle method), pH testing, mechanical testing, SEM imaging, XRD and FTIR analysis. In vitro degradation and elution behaviour were evaluated by monitoring calcium release (atomic absorbance spectroscopy), mechanical strength and vancomycin release (UV-visual spectrophotometry). CPP addition was found to increase the setting time, reduce the mechanical strength and inhibit the conversion of the CPC starting powders to the set apatitic phase. The most likely mechanism for the observed effect of CPP addition was the adsorption of polyphosphate chains on the particle surfaces, which would inhibit the dissolution of the starting powders and the conversion of apatite precursor phases to apatite, leading to reduced mechanical properties. The detrimental effects of CPP were reduced by limiting the CPP fraction to less than a few weight per cent and increasing the size of the CPP particulate. CPP

  6. Study of the de-excitation of the 44Ti nuclei light charged particles

    International Nuclear Information System (INIS)

    The deexcitation process of the 44Ti compound nuclei, produced by fusion-evaporation reactions, has been studied at bombarding energies Elab 44Ti has been populated through two reactions: 16O + 28Si at bombarding energies Elab(16O) = 76, 96 and 112 MeV, and 32S + 12C at Elab(32S) = 180 and 225 MeV. The exclusive experimental data, angular and energy distributions, have been analysed with the statistical code CACARIZO. The well identified evaporation channels have been precisely studied to determine the energy distributions of the residual nuclei. The calculations reproduce the sequential emission of α particles in the deexcitation chains, however, the emission of nucleons is partially misunderstood. In both reactions, the energy distribution of the protons indicates a temperature in residual nuclei lower than predicted. The dynamical deformation induced for the highest angular momenta has been quantified with an axis ratio of 2:1. (author)

  7. Piezonuclear Reactions

    CERN Document Server

    Cardone, Fabio; Petrucci, Andrea

    2010-01-01

    In this paper, we deal with the subject of piezonuclear reactions, namely nuclear reactions (of new type) triggered by pressure waves. We discuss the experimental evidences obtained in the last two decades, which can be summarized essentially as follows: experiments in cavitation of liquids, where transmutation of elements, creation of elements and emission of neutrons have been observed; emission of neutrons in brittle failure of solids subjected to mechanical pressure; alteration of the lifetime of un unstable element (thorium) subjected to cavitation. A theoretical model to explain these facts is proposed. Future perspectives of these experimental and theoretical investigations are also underlined.

  8. Reaction mechanisms

    International Nuclear Information System (INIS)

    The 1988 progress report of the Reaction Mechanisms laboratory (Polytechnic School, France), is presented. The research topics are: the valence bond methods, the radical chemistry, the modelling of the transition states by applying geometric constraints, the long range interactions (ion - molecule) in gaseous phase, the reaction sites in gaseous phase and the mass spectroscopy applications. The points of convergence between the investigations of the mass spectroscopy and the theoretical chemistry teams, as well as the purposes guiding the research programs, are discussed. The published papers, the conferences, the congress communications and the thesis, are also reported

  9. Mechanism of calcium phosphates precipitation in liquid crystals; Mecanisme de precipitation de phosphates de calcium dans des cristaux liquides

    Energy Technology Data Exchange (ETDEWEB)

    Prelot, B.; Zemb, T

    2004-04-01

    The possibility of using as a precursor an easily wet meso-porous powder would be a breakthrough in the preparation of nuclear waste storage ceramics. A concentrated solution containing ions to be stored would wet a dry powder and then, subjected to mild compression, lead to a micro-crystalline matrix of calcium phosphate at acceptable temperatures. Since no porous calcium phosphate different from calcined bone (patented) is described as porous precursor, we have compared the different synthesis routes towards meso-porous ceramics. First, we considered homogeneous precipitation of slats in water: using initially off-stoichiometry in reaction, micron-sized hydroxyapatite particles are produced with a specific surface up to 100 m{sup 2}/g. Then, we consider the classical route of precipitation of an hybrid material in the miscibility gap of a phase diagram, when an hexagonal liquid crystal is used a matrix for precipitation. The surfactant family consists in single chain surfactants containing phosphates as head-group to poison the growing surface of calcium phosphate nano-domains. Since the reaction is still too brutal, we considered using a cat-anionic precursor material of controllable surface charge. For certain concentrations and molar ratios, a new structure not yet described in surfactant precipitation literature is observed: since the periodicity is lower than twice the chain length, a disordered constant curvature monolayer (instead of the classical cylinder of twice chain length diameter) of surfactant is implied. Finally, we have investigated synthesis routes implying slow dissolution of pre-formed calcium phosphate in an already existing hexagonal matrix. For all these routes of synthesis, micro-structural determinations using SAXS, WARS and BET are performed, with a special attention to comparison of the precipitation material, the matrix obtained with all elements present, and also the material obtained after calcinations. (authors)

  10. The Validity and Reliability of the Turkish Version of the Obsessive Beliefs Questionnaire-44 (OBQ-44

    Directory of Open Access Journals (Sweden)

    Murat BOYSAN

    2010-09-01

    Full Text Available Objective: Cognitive factors have a central place in the etiology and persistenceof obsessive-compulsive disorder (OCD. The aim of the study was to evaluatepsychometric properties of the Turkish version of the ObsessiveBeliefs Questionnaire-44 (OBQ-44. Original factor structure of the OBQ-44 anddiscrimination characteristic of the instrument between OCD patients andnonclinical population were evaluated extensively in Turkish sample.Methods: Data were collected from 175 healthy subjects and 62 patients with OCDwho applied to the Psychiatry Clinic at Yüzüncü Y›l University. Subjects wereadministered the SCID-I, the Obsessive Beliefs Questionnaire-44 (OBQ-44, thePadua Inventory (PI-41, the Yale-Brown Obsessive Compulsive Scale (Y-BOKS,the Metacognitions Questionnaire-30 (MCQ-30, the Thought Action Fusion Scale(TAFS, the White Bear Suppression Inventory (WBSI, the Penn Inventory ofScrupulosity (PIOS, the Penn State Worry Questionnaire (PSWQ, and theBeck Depression Inventory (BDI. Data were analyzed in order to evaluate thereliability and validity of the OBQ-44.Results: The three-factor original structure tested using confirmatory factoranalysis was observed to be highly consistent with the data obtained from thestudy. OCD patients reported significantly higher scores on OBQ-44 rather thancontrols. Correlations of the OBQ-44 scores with psychological variables weregenerally significant. Inner consistency coefficient for the OBQ-44 was α0,95 andtest-retest correlation between two points at 30-day time course was r=0.79.Conclusion: The Turkish version of the OBQ-44 has adequate validity and reliability inclinical and nonclinical Turkish sample.(Archives of Neuropsychiatry 2010; 47: 216-22

  11. [Calcium pyrophosphate dihydrate deposition disease].

    Science.gov (United States)

    Koitschev, C; Kaiserling, E; Koitschev, A

    2003-08-01

    Calcium pyrophosphate dihydrate deposition disease (CPPD) of the temporomandibular joint is rare. The disorder is characterized by the presence of crystal deposits within the affected joint. The deposition of crystals in adjacent soft tissue may lead to the formation of pseudotumors. This form of the disease is called tophaceous pseudogout and typically affects the temporomandibular joint. It is difficult to differentiate the disease, particularly from malignant tumors, on the clinical and radiographic findings alone. The diagnosis is based on histological identification of the calcium pyrophosphate crystals. We present an unusually advanced case of tophaceous pseudogout of the temporomandibular joint. The etiology, clinical and diagnostic criteria as well as treatment options are discussed on the basis of our own experience and a review of the literature. PMID:12942180

  12. Testosterone increases urinary calcium excretion and inhibits expression of renal calcium transport proteins

    DEFF Research Database (Denmark)

    Hsu, Yu-Juei; Dimke, Henrik Anthony; Schoeber, Joost P H;

    2010-01-01

    Although gender differences in the renal handling of calcium have been reported, the overall contribution of androgens to these differences remains uncertain. We determined here whether testosterone affects active renal calcium reabsorption by regulating calcium transport proteins. Male mice had...... higher urinary calcium excretion than female mice and their renal calcium transporters were expressed at a lower level. We also found that orchidectomized mice excreted less calcium in their urine than sham-operated control mice and that the hypocalciuria was normalized after testosterone replacement...... calcium transport. Thus, our study shows that gender differences in renal calcium handling are, in part, mediated by the inhibitory actions of androgens on TRPV5-mediated active renal calcium transport....

  13. 44 CFR 150.3 - Nomination process.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Nomination process. 150.3... Nomination process. (a) The Nominating Officials nominating Firefighters and Civil Defense Officers shall... earliest practicable date after the performance of the act or acts for which the nomination is...

  14. 44 CFR 62.22 - Judicial review.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Judicial review. 62.22 Section 62.22 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... ADJUSTMENT OF CLAIMS Claims Adjustment, Claims Appeals, and Judicial Review § 62.22 Judicial review. (a)...

  15. 44 CFR 295.43 - Judicial review.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Judicial review. 295.43... Judicial review. As an alternative to arbitration, a Claimant dissatisfied with the outcome of an Administrative Appeal may seek judicial review of the decision by bringing a civil lawsuit against FEMA in...

  16. 44 CFR 6.57 - Judicial review.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Judicial review. 6.57 Section... SECURITY GENERAL IMPLEMENTATION OF THE PRIVACY ACT OF 1974 Requests To Amend Records § 6.57 Judicial review... requestor may seek judicial review of that determination. A civil action must be filed in the...

  17. 44 CFR 7.15 - Judicial review.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Judicial review. 7.15 Section...-Assisted Programs-General § 7.15 Judicial review. Action taken pursuant to section 602 of the Act is subject to judicial review as provided in section 603 of the Act....

  18. 44 CFR 19.405 - Housing.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Housing. 19.405 Section 19... Prohibited § 19.405 Housing. (a) Generally. A recipient shall not, on the basis of sex, apply different rules... related to housing, except as provided in this section (including housing provided only to...

  19. 44 CFR 206.3 - Policy.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 206.3 Section 206.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE General § 206.3 Policy. It is the policy of FEMA to...

  20. 44 CFR 327.3 - Policy.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 327.3 Section 327.3... PREPAREDNESS POLICY ON USE OF GOVERNMENT-OWNED INDUSTRIAL PLANT EQUIPMENT BY PRIVATE INDUSTRY (DMO-10A) § 327.3 Policy. (a) General. (1) Primary reliance for defense production shall be placed upon private...

  1. 44 CFR 206.341 - Policy.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 206.341 Section 206... SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Coastal Barrier Resources Act § 206.341 Policy. It shall be the policy of FEMA to achieve the goals of CBRA in carrying out disaster relief on units of...

  2. 44 CFR 312.3 - Policy.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 312.3 Section 312.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY... Policy. (a) It is the policy of FEMA to provide a means of assistance to States and their...

  3. 44 CFR 12.3 - Policy.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 12.3 Section 12.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL ADVISORY COMMITTEES § 12.3 Policy. In determining whether an advisory committee should be...

  4. 44 CFR 331.2 - Policy.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 331.2 Section 331.2... SURPLUS AREAS § 331.2 Policy. (a) It is the policy of the Federal Government to award appropriate... locating procurement where the needed labor force and facilities are fully available. (b) This policy...

  5. 44 CFR 334.2 - Policy.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 334.2 Section 334.2... PREPAREDNESS GRADUATED MOBILIZATION RESPONSE § 334.2 Policy. (a) As established in Executive Order 12656, the policy of the United States is to have sufficient emergency response capabilities at all levels...

  6. 44 CFR 10.4 - Policy.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 10.4 Section 10.4... GENERAL ENVIRONMENTAL CONSIDERATIONS General § 10.4 Policy. (a) FEMA shall act with care to assure that... mitigation and flood insurance, it does so in a manner consistent with national environmental policies....

  7. 44 CFR 295.2 - Policy.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 295.2 Section 295.2 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY CERRO GRANDE FIRE ASSISTANCE CERRO GRANDE FIRE ASSISTANCE General § 295.2 Policy. It is our policy...

  8. 44 CFR 9.2 - Policy.

    Science.gov (United States)

    2010-10-01

    ... Agency to provide leadership in floodplain management and the protection of wetlands. Further, the Agency... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Policy. 9.2 Section 9.2 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND...

  9. 44 CFR 79.9 - Grant administration.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Grant administration. 79.9... § 79.9 Grant administration. (a) The Grantee must follow FEMA grant requirements, including submission of performance and financial status reports, and shall follow adequate competitive...

  10. 44 CFR 206.365 - Loan administration.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Loan administration. 206.365... administration. (a) Funding. (1) FEMA will disburse funds to the local government when requested, generally in... government shall submit a copy of its most recent financial report (if not submitted previously)...

  11. 44 CFR 206.375 - Loan administration.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Loan administration. 206.375... administration. (a) Funding. (1) FEMA will disburse funds to the local government when requested, generally in... government shall submit a copy of its most recent financial report (if not submitted previously)...

  12. 44 CFR 13.41 - Financial reporting.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Financial reporting. 13.41... Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5) of this section... supplementary or other forms as may from time to time be authorized by OMB, for: (i) Submitting...

  13. 44 CFR 5.25 - Available materials.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Available materials. 5.25... Agency Information, Rules, Orders, Policies, and Similar Material § 5.25 Available materials. FEMA materials which are available under this subpart are as follows: (a) Final opinions and orders made in...

  14. 44 CFR 79.5 - Application process.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Application process. 79.5 Section 79.5 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... § 79.5 Application process. (a) Applicant or grantee. (1) States will be notified of the...

  15. 44 CFR 352.29 - Appeal process.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Appeal process. 352.29 Section 352.29 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... Participation § 352.29 Appeal process. (a) Any interested party may appeal a determination made by the...

  16. 44 CFR 10.7 - Planning.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Planning. 10.7 Section 10.7... GENERAL ENVIRONMENTAL CONSIDERATIONS Agency Implementing Procedures § 10.7 Planning. (a) Early planning. The Regional Administrator shall integrate the NEPA process with other planning at the...

  17. 44 CFR 71.4 - Documentation.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Documentation. 71.4 Section... LEGISLATION § 71.4 Documentation. (a) In order to obtain a new policy of flood insurance for a structure which... protected area,” the owner of the structure must submit the documentation described in this section in...

  18. 44 CFR 206.151 - Food commodities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Food commodities. 206.151... Food commodities. (a) The Administrator will assure that adequate stocks of food will be ready and... section, the Administrator may direct the Secretary of Agriculture to purchase food commodities...

  19. 44 CFR 402.2 - Restricted commodities.

    Science.gov (United States)

    2010-10-01

    ... Positive List (15 CFR part 399) (as amended from time to time) of the Comprehensive Export Schedule of the... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Restricted commodities. 402.2... SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.2 Restricted commodities. The...

  20. 44 CFR 312.5 - Personnel.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Personnel. 312.5 Section 312... SECURITY PREPAREDNESS USE OF CIVIL DEFENSE PERSONNEL, MATERIALS, AND FACILITIES FOR NATURAL DISASTER PURPOSES § 312.5 Personnel. FEMA contributes to the development and support of emergency...

  1. 44 CFR 19.310 - Recruitment.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Recruitment. 19.310 Section... RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 19.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 19.300 through...

  2. 44 CFR 19.510 - Recruitment.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Recruitment. 19.510 Section... Programs or Activities Prohibited § 19.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where...

  3. 42 CFR 414.44 - Transition rules.

    Science.gov (United States)

    2010-10-01

    ... § 414.44 Transition rules. (a) Adjusted historical payment basis—(1) All services other than radiology and nuclear medicine services. For all physician services other than radiology services, furnished in... prevailing charge applied in the fee schedule area for the service in CY 1991, as determined by CMS...

  4. 44 CFR 12.7 - Charter.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Charter. 12.7 Section 12.7 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY... also be furnished at the time of filing to the Library of Congress, Exchange and Gift Division,...

  5. 27 CFR 30.44 - Weighing containers.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Weighing containers. 30.44... Weighing containers. (a) Weighing containers of more than 10 wine gallons. The weight of containers having.... (b) Weighing containers of 10 wine gallons or less. The weight for containers of a capacity of...

  6. 44 CFR 350.9 - Exercises.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Exercises. 350.9 Section 350.9 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND... its boundaries or is within the 10-mile plume exposure pathway Emergency Planning Zone of such...

  7. 44 CFR 15.8 - Gambling.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Gambling. 15.8 Section 15.8... CENTER § 15.8 Gambling. We prohibit participating in games for money or other personal property, including the operation of gambling devices, the conduct of a lottery or pool, or the sale or purchase...

  8. 44 CFR 13.32 - Equipment.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Equipment. 13.32 Section 13... LOCAL GOVERNMENTS Post-Award Requirements Changes, Property, and Subawards § 13.32 Equipment. (a) Title. Subject to the obligations and conditions set forth in this section, title to equipment acquired under...

  9. 44 CFR 75.11 - Standards.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Standards. 75.11 Section 75... PROPERTIES UNDER SELF-INSURANCE PLAN Standards for Exemption § 75.11 Standards. (a) In order to be exempt... hazards which are covered under the Standard Flood Insurance Policy. (3) Provide coverage to...

  10. 44 CFR 9.5 - Scope.

    Science.gov (United States)

    2010-10-01

    ..., as amended, and the issuance of an exception to a community under 44 CFR 60.6(b). (See also § 9.9(e... and 306; (2) Emergency Support Teams (section 304); (3) Unemployment Assistance (section 407); (4... structure is one which has previously sustained structural damage from flooding due to a major disaster...

  11. 44 CFR 9.18 - Responsibilities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Responsibilities. 9.18... HOMELAND SECURITY GENERAL FLOODPLAIN MANAGEMENT AND PROTECTION OF WETLANDS § 9.18 Responsibilities. (a) Regional Administrators' responsibilities. Regional Administrators shall, for all actions falling...

  12. 44 CFR 10.5 - Responsibilities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Responsibilities. 10.5... Responsibilities. (a) The Regional Administrators shall, for each action not categorically excluded from this... impact statements and assign lead agency responsibility when more than one FEMA office or...

  13. 44 CFR 207.4 - Responsibilities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Responsibilities. 207.4... HOMELAND SECURITY DISASTER ASSISTANCE MANAGEMENT COSTS § 207.4 Responsibilities. (a) General. This section identifies key responsibilities of FEMA and grantees in carrying out section 324 of the Stafford Act, 42...

  14. 44 CFR 206.362 - Responsibilities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Responsibilities. 206.362 Section 206.362 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... Responsibilities. (a) The local government shall submit the financial information required by FEMA in...

  15. 44 CFR 79.3 - Responsibilities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Responsibilities. 79.3... § 79.3 Responsibilities. (a) Federal Emergency Management Agency (FEMA). Administer and provide... responsibilities of the “State” as the term is used in this part, as applicant or grantee, described in...

  16. 44 CFR 201.3 - Responsibilities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Responsibilities. 201.3... HOMELAND SECURITY DISASTER ASSISTANCE MITIGATION PLANNING § 201.3 Responsibilities. (a) General. This section identifies the key responsibilities of FEMA, States, and local/tribal governments in carrying...

  17. 44 CFR 206.372 - Responsibilities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Responsibilities. 206.372 Section 206.372 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... Responsibilities. (a) The local government shall submit the financial information required by FEMA in...

  18. 44 CFR 323.3 - Responsibilities.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Responsibilities. 323.3...) § 323.3 Responsibilities. (a) As stated in The National Plan for Emergency Preparedness, the direction of resources mobilization is a Federal responsibility. However, in the period immediately...

  19. Photovoltaic barometer 44% of growth in 2000

    International Nuclear Information System (INIS)

    During the year 2000, worldwide production of solar cells increased by 44% and installed capacity in the European Union rose by 29%. This trend should be reinforced in 2001 with new national programmes pertaining to grid-linked photovoltaic systems coming into effect and due to the increasing involvement of the big oil industrial groups in the sector. (author)

  20. 44 CFR 19.525 - Fringe benefits.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Fringe benefits. 19.525... Programs or Activities Prohibited § 19.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance,...

  1. 44 CFR 80.13 - Application information.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Application information. 80.13 Section 80.13 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT... deed restriction language, which shall be consistent with the FEMA model deed restriction that...

  2. 44 CFR 13.11 - State plans.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false State plans. 13.11 Section 13.11 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND... provisions, (2) Repeat the assurance language in the statutes or regulations, or (3) Develop its own...

  3. 44 CFR 1.8 - Regulations review.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Regulations review. 1.8 Section 1.8 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... the rule from the public; (3) The complexity of the rule, including need for review of language...

  4. 44 CFR 80.21 - Closeout requirements.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Closeout requirements. 80.21 Section 80.21 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... restriction language to meet the requirements of this part; (b) A photo of each property site after...

  5. 44 CFR 19.235 - Statutory amendments.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Statutory amendments. 19.235 Section 19.235 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... of factors related to the individual's personal appearance, poise, and talent. The pageant,...

  6. 44 CFR 208.43 - Rehabilitation.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Rehabilitation. 208.43... Agreements § 208.43 Rehabilitation. DHS will reimburse costs incurred to return System equipment and... Activation. (3) Personnel costs associated with equipment cache rehabilitation. DHS will reimburse...

  7. 44 CFR 16.160 - Communications.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Communications. 16.160... ACTIVITIES CONDUCTED BY THE FEDERAL EMERGENCY MANAGEMENT AGENCY § 16.160 Communications. (a) The agency shall take appropriate steps to ensure effective communication with applicants, participants, personnel...

  8. 44 CFR 7.942 - Mediation.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Mediation. 7.942 Section 7..., Conciliation, and Enforcement Procedures § 7.942 Mediation. (a) FEMA will promptly refer to a mediation agency... participate in the mediation process to the extent necessary to reach an agreement or for the mediator to...

  9. 44 CFR 295.42 - Arbitration.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Arbitration. 295.42 Section... SECURITY CERRO GRANDE FIRE ASSISTANCE CERRO GRANDE FIRE ASSISTANCE Dispute Resolution § 295.42 Arbitration. (a) Initiating arbitration. A Claimant who is dissatisfied with the outcome of the...

  10. 44 CFR 59.4 - References.

    Science.gov (United States)

    2010-10-01

    ... 1954, as amended by the Housing and Community Development Act of 1974 (24 CFR 600.72). (12) Executive... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false References. 59.4 Section 59.4... References. (a) The following are statutory references for the National Flood Insurance Program, under...

  11. 44 CFR 5.46 - Fee schedule.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Fee schedule. 5.46 Section 5... SECURITY GENERAL PRODUCTION OR DISCLOSURE OF INFORMATION Fees § 5.46 Fee schedule. (a) Manual searches for... schedule programs, such as but not limited to the Government Printing Office or the National...

  12. 44 CFR 72.3 - Fee schedule.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Fee schedule. 72.3 Section 72.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND... PROCESSING MAP CHANGES § 72.3 Fee schedule. (a) For requests for CLOMRs, LOMRs, and PMRs based on...

  13. 44 CFR 295.41 - Administrative appeal.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Administrative appeal. 295.41 Section 295.41 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... supplement the statement of reasons and provide any additional documentary evidence supporting the...

  14. 44 CFR 68.9 - Admissible evidence.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Admissible evidence. 68.9 Section 68.9 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... admissible. (b) Documentary and oral evidence shall be admissible. (c) Admissibility of non-expert...

  15. 44 CFR 5.3 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Definitions. 5.3 Section 5.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY... means all books, papers, maps, photographs, or other documentary materials, regardless of physical...

  16. 44 CFR 300.3 - Financial assistance.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Financial assistance. 300.3... HOMELAND SECURITY PREPAREDNESS DISASTER PREPAREDNESS ASSISTANCE § 300.3 Financial assistance. (a) The... responsibilities for IFG, crisis counseling, mass care or other functional responsibilities; (7) Training for...

  17. 44 CFR 150.7 - Selection process.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Selection process. 150.7... Selection process. (a) President's Award. Nominations for the President's Award shall be reviewed, and... cause an evaluation and selection of the nominees to be made in accordance with the requirements...

  18. HI in Group Interactions: HCG 44

    CERN Document Server

    Hess, Kelley M; Yahya, Sahba; Leisman, Lukas; Serra, Paolo; Lucero, Danielle M; Passmoor, Sean S; Carignan, Claude

    2016-01-01

    Extending deep observations of the neutral atomic hydrogen (HI) to the environment around galaxy groups can reveal a complex history of group interactions which is invisible to studies that focus on the stellar component. Hickson Compact Group 44 (HCG 44) is a nearby example and we have combined HI data from the Karoo Array Telescope, Westerbork Synthesis Radio Telescope, and Arecibo Legacy Fast ALFA survey, in order to achieve high column density sensitivity (N_HI < 2x10^18 cm^-2) to the neutral gas over a large field-of-view beyond the compact group itself. We find the giant HI tail north of HCG 44 contains 1.1x10^9 M_Sun of gas and extends 450 kpc from the compact group: twice as much mass and 33% further than previously detected. However, the additional gas is still unable to account for the known HI deficiency of HCG 44. The tail likely formed through a strong tidal interaction and HI clouds in the tail have survived for 1 Gyr or more after being stripped. This has important implications for understan...

  19. 44 CFR 206.345 - Exceptions.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Exceptions. 206.345 Section 206.345 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF..., and of the access thereto; (4) Repair of facilities for scientific research, including but not...

  20. 44 CFR 67.8 - Appeal procedure.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Appeal procedure. 67.8 Section 67.8 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... technical or scientific data submitted by the community that tend to negate or contradict the...

  1. 44 CFR 7.10 - Compliance information.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Compliance information. 7.10... in FEMA-Assisted Programs-General § 7.10 Compliance information. (a) Cooperation and assistance. The... such information, as the responsible agency official or his designee may determine to be necessary...

  2. 44 CFR 5.6 - Congressional information.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Congressional information. 5... HOMELAND SECURITY GENERAL PRODUCTION OR DISCLOSURE OF INFORMATION General Provisions § 5.6 Congressional information. Nothing in this part authorizes withholding information from the Congress except when...

  3. 44 CFR 321.8 - Reports.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Reports. 321.8 Section 321.8... ADMINISTRATION) § 321.8 Reports. The Department of Defense, Department of Energy, and Maritime Administration shall furnish the Administrator of the Federal Emergency Management Agency with reports on items...

  4. 44 CFR 401.3 - Reports.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Reports. 401.3 Section 401.3... RESTRICTIONS (T-1) § 401.3 Reports. Persons subject to this order shall submit such reports to the Assistant... Reports Act....

  5. 44 CFR 327.5 - Reports.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Reports. 327.5 Section 327.5 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY... Reports. Such reports of operations under this order as may be required by the Federal...

  6. 44 CFR 206.343 - Scope.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Scope. 206.343 Section 206.343 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND... orientation which is unrelated to development is not subject to the requirements of these regulations....

  7. 44 CFR 19.500 - Employment.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Employment. 19.500 Section 19.500 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND... from leaves of absence, leave for pregnancy, childbirth, false pregnancy, termination of...

  8. 44 CFR 19.300 - Admission.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Admission. 19.300 Section 19.300 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND... against or exclude any person on the basis of pregnancy, childbirth, termination of pregnancy, or...

  9. 44 CFR 9.4 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... Disaster Relief Act of 1974 (42 U.S.C. 5145 and 5146). See 44 CFR part 205, subpart E. Enhance means to... resource values (agriculture, aquaculture, forestry). New Construction means the construction of a new... Places or a State Inventory of Historic Places. Support means to encourage, allow, serve or...

  10. 44 CFR 209.2 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... project, in accordance with FEMA guidance and using a FEMA-approved methodology. FEMA will review the... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Definitions. 209.2 Section 209.2 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF...

  11. 44 CFR 19.540 - Advertising.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Advertising. 19.540 Section 19.540 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR...

  12. Influence of calcium oxalate crystal accumulation on the calcium content of seeds from Medicago truncatula.

    Science.gov (United States)

    Nakata, Paul A

    2012-04-01

    Crystals of calcium oxalate often form in cells adjacent to the vascular bundles in the tissues along the xylem stream. This spatial crystal pattern suggests a role for calcium oxalate formation in regulating calcium transport and partitioning to edible organs such as seeds. To investigate this potential role, microscopic and biochemical comparisons were conducted on the different tissues of Medicago truncatula wild-type and the calcium oxalate defective (cod) 5 which lacks the ability to accumulate prismatic crystals in the cells adjacent to the vascular bundles. Calcium measurements showed that cod5 seeds had more calcium and cod5 pods contained less calcium than the corresponding wild-type tissues. Roots, stems, and leaves from cod5 and wild-type had similar calcium content. Although cod5 was devoid of prismatic crystals, cod5 pods were observed to form druse crystals of calcium oxalate not found in wild-type pods. Taken together these findings suggest a functional role for calcium oxalate formation in regulating calcium transport to the seeds. Regulating calcium uptake at the roots also appeared to be another point of control in determining seed calcium content. Overall, regulating the long distance transport and partitioning of calcium to the seeds appears to be a complex process with multiple points of control. PMID:22325887

  13. Serum calcium in pulmonary tuberculosis

    OpenAIRE

    Subhash C. Sharma

    1981-01-01

    Serum calcium was studied serially in 94 patients with active pulmonary tuberculosis. An equal number of age- and sex-matched patients with chronic obstructive pulmonary disease were controls. Seventy patients in the study group were normocalcaemic and 10 were hypercalcaemic. These 10 were on a higher supplement of vitamin D than the 70 normocalcaemic patients. There was a positive correlation between the daily vitamin intake and the degree and duration of hypercalcaemia. None of the controls...

  14. Effects on anionic salts in a pre-partum dairy ration on calcium metabolism

    Directory of Open Access Journals (Sweden)

    C.J. Van Dijk

    2001-07-01

    Full Text Available The effects of anionic salts in the transition diet on serum and urine calcium at calving and on peripartal health, subsequent milk production and fertility performance were studied in a well-managed, high-producing Friesland dairy herd. Over a period of a year, approximately 21 days before the expected date of calving, 28 pre-partum heifers and 44 multiparous dry cows were randomly allocated within parity to 1 of 2 transition diets, designated control and experimental anionic diets. The anionic diet contained the same quantities of the basic transition ration fed to the control group as well as a standard anionic salt mixture containing 118 g NH4Cl, 36 g (NH42SO4 and 68 g MgSO4 (total 222 g per animal per day. This reduced the DCAD to -11.68 mEq/100 g dietary dry matter compared to +13.57 for the control diet. Blood and urine were randomly sampled from 7 to 8 animals within each category within 3 hours post-partum. Serum calcium (total and ionised and creatinine, urine calcium and creatinine and the fractional clearance of calcium were assessed. Relevant clinical, milk production, and fertility data were collected. The total serum calcium (2.07 versus 1.60 mmol/ , serum ionised calcium (1.12 vs 1.02 mmol/ , urine calcium (0.92 vs 0.10 mmol/ and the fractional clearance of calcium (1.88 vs 0.09 % were significantly higher (P <0.01 at calving for multiparous cows fed the anionic diet compared to those fed the control diet. In the primiparous cows there were no significant differences in serumcalcium levels. However, the urine calcium (1.07 vs 0.43 mmol/ and the fractional clearance of calcium was higher (1.75 vs 0.45 % in cows fed the anionic diet (P <0.05 and 0.01 respectively. These results illustrated that there were benefits, although no differences were demonstrated with respect to health, milk production or fertility. The supplementation of diets with anionic salts in the last 2-3 weeks before calving has the potential to significantly

  15. Mechanisms of calcium transport in small intestine. Overall review of the contract, September 1, 1972--March 1, 1976

    Energy Technology Data Exchange (ETDEWEB)

    DeLuca, H.F.

    1976-01-01

    Progress is reported in the following areas of research: role of high molecular weight protein in calcium transport in vitamin D deficient chicks; subcellular localization of 1,25-(OH)/sub 2/D/sub 3/; receptor proteins for 1,25-(OH)/sub 2/D/sub 3/; effects of high calcium diet, strontium diet, EHDP, and parathyroidectomy on intestinal calcium transport in chicks; effects of analogs of 1,25-(OH)/sub 2/D/sub 3/ on intestinal calcium transport; discrimination by chicks against vitamin D/sub 2/ compounds by metabolism; effects of extract of Solanum malacoxylan on intestinal calcium absorption in nephrectomized rats; and role of vitamin D in phosphate transport reactions in the intestine. (HLW)

  16. Synthesis, crystal structures, and magnetic properties of two three-dimensional octacyanotungstate(Ⅳ)-based bimetallic frameworks with 4,4'-bipyridine dioxide (4,4'-dpdo)

    Institute of Scientific and Technical Information of China (English)

    YUAN Mei; GAO Song; ZHAO Fei; ZHANG Wen; WANG Zhe-Ming

    2009-01-01

    The reaction of [HN(n-C4H9)3]3[WⅤ(CN)8]·4H2O, 4,4'-bipyridine dioxide(4,4'-dpdo), end MnCl2·4H2O or crystallizes in the orthorhombic system, space group P21212 with cell constants α=10.397(2) A, b=11.321(2) A, c=12.295(3) A and Z=2, whereas 2 crystallizes in the monoclinic system, space group P21/c with cell constants a=13.038(3) A, b=13.784(3) A, c=13.225(3) A, β=93.44(3)g and Z=4. In complex 1, each [WⅣ(CN)8]4- unit with a square antiprismatic geometry is connected to four Mn2 dimers through four bridging CN- ions forming wavelike alternating -W-Mn2-W-Mn2- layers, which are further linked through 4,4'-dpdo ligands coordinated to the Mn ions into a three-dimensional open framework. In complex 2, each [WⅣ(CN)8]4- ion still adopts a square antiprismallc geometry, whereas it bonds to seven copper ions through seven CN- ions leading to cage-like undulate layers further bridged by 4,4'-dpdo ligands into a three-dimensional network. Due to the bridging role of the long rigid 4,4"-dpdo ligand, there exist plenty of large cavities in the open frameworks of complexes 1 and 2 occupied by solvent clusters containing H2O or CH3OH molecules. To our knowledge, it is noted that 4,4'-dpdo displays a μ-4,4,4',4' mode, which was first experimentally observed, although predicted before. Magnetic studies show that complex 1 displays an antiferromagnetic coupling between MnⅡ ions, while complex 2 ex-hibits a weak ferromagnetic interaction between CuⅡ ions.

  17. CCN3 and calcium signaling

    Directory of Open Access Journals (Sweden)

    Li Chang Long

    2003-08-01

    Full Text Available Abstract The CCN family of genes consists presently of six members in human (CCN1-6 also known as Cyr61 (Cystein rich 61, CTGF (Connective Tissue Growth Factor, NOV (Nephroblastoma Overexpressed gene, WISP-1, 2 and 3 (Wnt-1 Induced Secreted Proteins. Results obtained over the past decade have indicated that CCN proteins are matricellular proteins, which are involved in the regulation of various cellular functions, such as proliferation, differentiation, survival, adhesion and migration. The CCN proteins have recently emerged as regulatory factors involved in both internal and external cell signaling. CCN3 was reported to physically interact with fibulin-1C, integrins, Notch and S100A4. Considering that, the conformation and biological activity of these proteins are dependent upon calcium binding, we hypothesized that CCN3 might be involved in signaling pathways mediated by calcium ions. In this article, we review the data showing that CCN3 regulates the levels of intracellular calcium and discuss potential models that may account for the biological effects of CCN3.

  18. Class and Home Problems: Carbon Dioxide Capture from Coal-Fired Power Plants Using Calcium Looping

    Science.gov (United States)

    Deshpande, Niranjani; Phalak, Nihar; Fan, Liang-Shih; Sundaresan, Sankaran

    2015-01-01

    Calcium looping is based on the simple premise of the reversible reaction between CO[subscript 2] and CaO. This reaction can be used for separation of CO2 from a mixture of gases; most notably the technology finds applications in CO[subscript 2] removal from gas streams in fossil fuel-based energy systems. This article gives a brief overview of…

  19. ANNUAL REPORT. THE INFLUENCE OF CALCIUM CARBONATE GRAIN COATINGS ON CONTAMINANT REACTIVITY IN VADOSE ZONE SEDIMENTS

    Science.gov (United States)

    The primary objective of this project is to investigate the role of calcium carbonate grain coatings on adsorption and heterogeneous reduction reactions of key chemical and radioactive contaminants in sediments on the Hanford Site. Research will ascertain whether these coatings p...

  20. The use of calcium carbide in one-pot synthesis of symmetric diaryl ethynes.

    Science.gov (United States)

    Zhang, Weiwei; Wu, Huayue; Liu, Zhiqing; Zhong, Ping; Zhang, Lin; Huang, Xiaobo; Cheng, Jiang

    2006-12-14

    An efficient Pd-catalyzed copper and amine free coupling reaction of acetylene and aryl bromides was achieved with calcium carbide as an acetylene source, using inorganic base and easily prepared, air-stable aminophosphine ligand in common organic solvents, providing symmetric diaryl ethynes in one-pot with yields ranged from moderate to excellent. PMID:17345742

  1. Effect of calcium on adsorptive removal of As(III) and As(V) by iron oxide-based adsorbents

    KAUST Repository

    Uwamariya, V.

    2014-06-25

    The effects of calcium on the equilibrium adsorption capacity of As(III) and As(V) onto iron oxide-coated sand (IOCS) and granular ferric hydroxide (GFH) were investigated through batch experiments, rapid small-scale column tests (RSSCT) and kinetics modelling. Batch experiments showed that at calcium concentrations≤20 mg/L, high As(III) and As(V) removal efficiencies by IOCS and GFH are achieved at pH 6. An increase of the calcium concentration to 40 and 80 mg/L reversed this trend, giving higher removal efficiencies at higher pH (8). The adsorption capacities of IOCS and GFH at an equilibrium arsenic concentration of 10 g/L were found to be between 2.0 and 3.1 mg/g for synthetic water without calcium and between 2.8 and 5.3 mg/g when 80 mg/L of calcium was present at the studied pH values. After 10 hours of filter run in RSSCT, approximately 1000 empty bed volumes, the ratios of C/Co for As(V) were 26% and 18% for calcium-free model water; and only 1% and 0.2% after addition of 80 mg/L of Ca for filter columns with IOCS and GFH, respectively. The adsorption of As(III) and As(V) onto GFH follows a second-order reaction, with and without addition of calcium. The adsorption of As(III) and As(V) onto IOCS follows a first-order reaction without calcium addition, and moves to the second-reaction-order kinetics when calcium is added. Based on the intraparticle diffusion model, the main controlling mechanism for As(III) adsorption is intraparticle diffusion, while surface diffusion contributes greatly to the adsorption of As(V).

  2. The role of calcium in human aging.

    Science.gov (United States)

    Beto, Judith A

    2015-01-01

    Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance. PMID:25713787

  3. Rapid screening assay for calcium bioavailability studies

    International Nuclear Information System (INIS)

    Calcium bioavailability has been studied by numerous techniques. The authors report here the use of the gamma emitting isotope of calcium (47Ca) in a whole body retention assay system. In this system, calcium sources are administered by oral gavage and subsequent counts are determined and corrected for isotopic decay. Unlike iron and zinc retention curves, which exhibit a 2-3 day equilibration period, calcium reaches equilibration after 24 hours. Autoradiographic analysis of the femurs indicate that the newly absorbed calcium is rapidly distributed to the skeletal system. Moreover, the isotope is distributed along the entire bone. Comparisons of calcium bioavailability were made using intrinsic/extrinsic labeled milk from two species i.e. rat and goat as well as CaCO3. In addition, extrinsic labeled cow milk was examined. In the rat, the extrinsic labeled calcium from milk was better absorbed than the intrinsic calcium. This was not the case in goat milk or the calcium carbonate which exhibited no significant differences. Chromatographic analysis of the labeled milk indicates a difference in distribution of the 47Ca. From these data, the authors recommend the use of this assay system in calcium bioavailability studies. The labeling studies and comparisons indicate caution should be used, however, in labeling techniques and species milk comparison

  4. STIM1 is a Calcium Sensor Specialized for Digital Signaling

    OpenAIRE

    Bird, Gary S.; Hwang, Sung-Yong; Smyth, Jeremy T.; Fukushima, Miwako; Boyles, Rebecca R.; Putney, James W.

    2009-01-01

    When cells are activated by calcium-mobilizing agonists at low, physiological concentrations, the resulting calcium signals generally take the form of repetitive regenerative discharges of stored calcium, termed calcium oscillations [1]. These intracellular calcium oscillations have long fascinated biologists as representing a mode of digitized intracellular signaling. Recent work has highlighted the role of calcium influx as an essential component of calcium oscillations [2]. This influx occ...

  5. Functionalizing Liposomes with anti-CD44 Aptamer for Selective Targeting of Cancer Cells.

    Science.gov (United States)

    Alshaer, Walhan; Hillaireau, Hervé; Vergnaud, Juliette; Ismail, Said; Fattal, Elias

    2015-07-15

    CD44 receptor protein is found to be overexpressed by many tumors and is identified as one of the most common cancer stem cell surface markers including tumors affecting colon, breast, pancreas, and head and neck, making this an attractive receptor for therapeutic targeting. In this study, 2'-F-pyrimidine-containing RNA aptamer (Apt1), previously selected against CD44, was successfully conjugated to the surface of PEGylated liposomes using the thiol-maleimide click reaction. The conjugation of Apt1 to the surface of liposomes was confirmed by the change in size and zeta potential and by migration on agarose gel electrophoresis. The binding affinity of Apt1 was improved after conjugation compared to free-Apt1. The cellular uptake for Apt1-Lip was tested by flow cytometry and confocal imaging using the two CD44(+) cell lines, human lung cancer cells (A549) and human breast cancer cells (MDA-MB-231), and the CD44(-) cell line, mouse embryonic fibroblast cells (NIH/3T3). The results showed higher sensitivity and selectivity for Apt1-Lip compared to the blank liposomes (Mal-Lip). In conclusion, we demonstrate a successful conjugation of anti-CD44 aptamer to the surface of liposome and binding preference of Apt1-Lip to CD44-expressing cancer cells and conclude to a promising potency of Apt1-Lip as a specific drug delivery system. PMID:25343502

  6. Relationship of Calcium with Renal, Intestinal and Hormonal Status in Healthy Women

    International Nuclear Information System (INIS)

    The present study was performed on 38 healthy female volunteers to assess the role of renal, intestinal and hormonal control of calcium level in female with different ages. Women were divided into 4 groups: 25-35 years (12 females), 36-43 years (9 females), 44-49 years (10 females) and 55-59 years (7 females). From the fasting blood sample at the mid menstrual cycle (first three groups), the following parameters were determined: Hemoglobin, fasting blood sugar, creatinine, uric acid, calcium, inorganic phosphorus, magnesium, vitamin B12, folic acid, testosterone, progesterone, prolactin, thyroxin, female Follicle stimulating hormone (FSH) ,and Luteinizing hormone LH. Significant increase in uric acid and creatinine, and significant decrease of folic acid and vitamin B12 were detected among the last group. In addition, there are several significant correlations between calcium and other parameters tested in the first three groups while, no any significant correlation was detected in the last group. These results denoted that increased calcium excretion due to partial renal insufficiency in the elder females could play a role in calcium homeostasis rather than intestinal absorption

  7. Modelling of a plasma reactor for the synthesis of calcium carbide

    International Nuclear Information System (INIS)

    Plasma synthesis of calcium carbide was investigated using calcium oxide and graphite powders. A semi-batch spout-fluid bed reactor with a DC plasma torch was used for the study. Argon was used to initiate the plasma and hydrogen gas was then added to increase power and raise the plasma jet enthalpy. Experimental results showed that the reactor consisted of two different zones: a high temperature reaction zone and a well minded isothermal bed zone. The size of the reaction zone and the particle flow rate into the jet depended on the net plasma power. The reaction rate was correlated by a shrinking core, reaction control model and showed excellent fit for conditions where hydrogen was present in the plasma gas and heat transfer limitations were negligible. The apparent activation energy of the reaction was determined to be 377 kJ/mol (90 kcal/mol). Extrapolatin of the reaction model and the experimental results indicated that a plasma fluid bed process could be a technically viable and a more efficient alternative for the production of calcium carbide

  8. Production of a {sup 44} Ti target and its cross section of thermal neutron capture; Producao de um alvo de {sup 44} Ti e sua secao de choque para captura de neutrons termicos

    Energy Technology Data Exchange (ETDEWEB)

    Ejnisman, R

    1993-12-31

    A study of the production of a {sup 44} Ti target was carried out aiming the determination of its thermal neutron capture cross-section. With this purpose, the cross-section of the reaction {sup 45} Sc(p,2 n) {sup 44} Ti was determined in the energies 16-, 18-, 20-22- and 45 MeV. The cross-section of the reactions (p,n) {sup 45} Ti, (p,pn) {sup 44m} Sc, (p,pn) {sup 44g} Sc and (p,p2n){sup 43} Sc were also measured. The results in the low energy region are in good agreement with a previous work by McGee et al. On the other hand, the cross-section at 45 MeV is different from McGee`s result and indicates the existence of an abnormal behavior of the excitation function at higher energies. Furthermore, a radiochemical separation method was developed in order to eliminate Sc from the {sup 44} Ti target which was irradiated with neutrons. It was possible to determine an upper limit for the cross-section of the reaction {sup 44} Ti (n, {gamma}) of 4 x 10{sup 3} b. At last, it is presented a discussion of the results obtained and their possible astrophysical implications. (author) 94 refs.

  9. 44 CFR 206.207 - Administrative and audit requirements.

    Science.gov (United States)

    2010-10-01

    ... administrative requirements of 44 CFR parts 13 and 206; (H) Compliance with the audit requirements of 44 CFR part... in FEMA regulations at 44 CFR part 13 or OMB Circular A-110 as appropriate. (2) Federal audit. In accordance with 44 CFR part 13, FEMA may elect to conduct a Federal audit of the disaster assistance grant...

  10. Fortification of all-purpose wheat-flour tortillas with calcium lactate, calcium carbonate, or calcium citrate is acceptable.

    Science.gov (United States)

    Romanchik-Cerpovicz, Joelle E; McKemie, Rebecca J

    2007-03-01

    Fortification helps provide adequate nutrients for individuals not meeting daily needs. Foods may be fortified with calcium to assist individuals with lactose intolerance and others preferring not to consume traditional forms of dairy. This study examined the quality of all-purpose wheat-flour tortillas fortified with calcium lactate, calcium carbonate, or calcium citrate. These tortillas were compared to similarly prepared nonfortified flour tortillas (control) and commercial nonfortified flour tortillas. Calcium-fortified tortillas contained 114 mg elemental calcium per standard serving (48 g tortilla), an 8.6-fold increase compared to nonfortified tortillas. Moisture contents and rollabilities of all tortillas were similar. Consumers (N=87) evaluated each tortilla in duplicate using a hedonic scale and reported liking the appearance, texture, flavor, aftertaste, and overall acceptability of all tortillas. However, the appearance of control tortillas was preferred over commercial tortillas (Ptortillas or those fortified with calcium carbonate was preferred over the control (Ptortillas, suggesting that appearance and aftertaste may not influence willingness to purchase. Overall, this study shows that fortification of flour tortillas with various forms of calcium is a feasible alternative calcium source. PMID:17324671

  11. Calcium carbonate crystallisation at the microscopic level

    CERN Document Server

    Dobson, P S

    2001-01-01

    The primary concern of this thesis is the investigation of crystal nucleation and growth processes, and the effect of foreign substrates on the rate, extent and mechanism of crystallisation, with particular emphasis on the calcium carbonate system. A methodology, based on the in-line mixing of two stable solutions, which permits the continuous delivery of a solution with a constant, known supersaturation, has been developed and characterised. This has been used to induce CaCO sub 3 crystallisation in experimental systems involving the channel flow and wall jet techniques. The channel flow method has been adapted to facilitate the study of crystal growth at a single calcite crystal. Ca sup 2 sup + ion selective electrodes have been employed as a means of monitoring depletion of the supersaturated solution, downstream of the crystal substrate. The data obtained suggested a growth rate constant of 3x10 sup - sup 1 sup 2 mol cm sup - sup 2 s sup - sup 1 (and a reaction order of 1.52 on supersaturation). The ex-si...

  12. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Go J., E-mail: medical21go@yahoo.co.jp; Saya, Hideyuki

    2014-01-10

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup high}/ c-Myc {sup low} and proliferative cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup low}/ c-Myc {sup high}.

  13. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    International Nuclear Information System (INIS)

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 high/ Fbw7 high/ c-Myc low and proliferative cancer stem-like cells with CD44v8-10 high/ Fbw7 low/ c-Myc high

  14. Binding of calcium and carbonate to polyacrylates.

    Science.gov (United States)

    Tribello, Gareth A; Liew, CheeChin; Parrinello, Michele

    2009-05-21

    Polyacrylate molecules can be used to slow the growth of calcium carbonate. However, little is known about the mechanism by which the molecules impede the growth rate. A recent computational study (Bulo et al. Macromolecules 2007, 40, 3437) used metadynamics to investigate the binding of calcium to polyacrylate chains and has thrown some light on the coiling and precipitation of these polymers. We extend these simulations to examine the binding of calcium and carbonate to polyacrylate chains. We show that calcium complexed with both carbonate and polyacrylate is a very stable species. The free energies of calcium-carbonate-polyacrylate complexes, with different polymer configurations, are calculated, and differences in the free energy of the binding of carbonate are shown to be due to differences in the amount of steric hindrance about the calcium, which prevents the approach of the carbonate ion. PMID:19400592

  15. Calcium Carbide: A Unique Reagent for Organic Synthesis and Nanotechnology.

    Science.gov (United States)

    Rodygin, Konstantin S; Werner, Georg; Kucherov, Fedor A; Ananikov, Valentine P

    2016-04-01

    Acetylene, HC≡CH, is one of the primary building blocks in synthetic organic and industrial chemistry. Several highly valuable processes have been developed based on this simplest alkyne and the development of acetylene chemistry has had a paramount impact on chemical science over the last few decades. However, in spite of numerous useful possible reactions, the application of gaseous acetylene in everyday research practice is rather limited. Moreover, the practical implementation of high-pressure acetylene chemistry can be very challenging, owing to the risk of explosion and the requirement for complex equipment; special safety precautions need to be taken to store and handle acetylene under high pressure, which limit its routine use in a standard laboratory setup. Amazingly, recent studies have revealed that calcium carbide, CaC2 , can be used as an easy-to-handle and efficient source of acetylene for in situ chemical transformations. Thus, calcium carbide is a stable and inexpensive acetylene precursor that is available on the ton scale and it can be handled with standard laboratory equipment. The application of calcium carbide in organic synthesis will bring a new dimension to the powerful acetylene chemistry. PMID:26898248

  16. A honeycomb composite of mollusca shell matrix and calcium alginate.

    Science.gov (United States)

    You, Hua-jian; Li, Jin; Zhou, Chan; Liu, Bin; Zhang, Yao-guang

    2016-03-01

    A honeycomb composite is useful to carry cells for application in bone, cartilage, skin, and soft tissue regenerative therapies. To fabricate a composite, and expand the application of mollusca shells as well as improve preparing methods of calcium alginate in tissue engineering research, Anodonta woodiana shell powder was mixed with sodium alginate at varying mass ratios to obtain a gel mixture. The mixture was frozen and treated with dilute hydrochloric acid to generate a shell matrix/calcium alginate composite. Calcium carbonate served as the control. The composite was transplanted subcutaneously into rats. At 7, 14, 42, and 70 days after transplantation, frozen sections were stained with hematoxylin and eosin, followed by DAPI, β-actin, and collagen type-I immunofluorescence staining, and observed using laser confocal microscopy. The composite featured a honeycomb structure. The control and composite samples displayed significantly different mechanical properties. The water absorption rate of the composite and control group were respectively 205-496% and 417-586%. The composite (mass ratio of 5:5) showed good biological safety over a 70-day period; the subcutaneous structure of the samples was maintained and the degradation rate was lower than that of the control samples. Freezing the gel mixture afforded control over chemical reaction rates. Given these results, the composite is a promising honeycomb scaffold for tissue engineering. PMID:26700239

  17. 44 BWR Waste Package Loading Curve Evaluation

    International Nuclear Information System (INIS)

    The objective of this calculation is to evaluate the required minimum burnup as a function of average initial boiling water reactor (BWR) assembly enrichment that would permit loading of fuel into a potential 44 BWR waste package (WP). The potential WP design is illustrated in Attachment I. The scope of this calculation covers a range of initial enrichments from 1.5 through 5.0 weight percent U-235, and a burnup range of 0 through 50 GWd/mtU

  18. 44 BWR Waste Package Loading Curve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    J.M. Scaglione

    2001-11-05

    The objective of this calculation is to evaluate the required minimum burnup as a function of average initial boiling water reactor (BWR) assembly enrichment that would permit loading of fuel into a potential 44 BWR waste package (WP). The potential WP design is illustrated in Attachment I. The scope of this calculation covers a range of initial enrichments from 1.5 through 5.0 weight percent U-235, and a burnup range of 0 through 50 GWd/mtU.

  19. LERF Basin 44 Process Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    LUECK, K.J.

    1999-08-31

    This document presents a plan to process a portion of the Liquid Effluent Retention Facility (LERF) Basin 44 wastewater through the 200 Area Effluent Treatment Facility (ETF). The objective of this process test is to determine the most effective/efficient method to treat the wastewater currently stored in LERF Basin 44. The process test will determine the operational parameters necessary to comply with facility effluent discharge permit limits (Ecology 1995) and the Environmental Restoration Disposal Facility (ERDF) acceptance criteria (BHI-00139), while achieving ALARA goals and maintaining the integrity of facility equipment. A major focus of the test plan centers on control of contamination due to leaks and/or facility maintenance. As a pre-startup item, all known leaks will be fixed before the start of the test. During the course of the test, a variety of contamination control measures will be evaluated for implementation during the treatment of the remaining Basin 44 inventory. Of special interest will be techniques and tools used to prevent contamination spread during sampling and when opening contaminated facility equipment/piping. At the conclusion of the test, a post ALARA review will be performed to identify lessons learned from the test run which can be applied to the treatment of the remaining Basin 44 inventory. The volume of wastewater to be treated during this test run is 500,000 gallons. This volume limit is necessary to maintain the ETF radiological inventory limits per the approved authorization basis. The duration of the process test is approximately 30 days.

  20. Translocation and bonding of calcium (45Ca) in two-year-old seedlings of spruce (Picea abies[L.] Karst.) and pine (Pinus sylvestris L.)

    International Nuclear Information System (INIS)

    Within the framework of the project ''Effect of liming and magnesium fertilization on the uptake, transport, and chemical bonding form of calcium and magnesium in conifers'', experiments regarding the calcium budget of two-year-old spruce and pine seedlings under conditions of controlled nutrition in a gravel culture were carried out. Two variants of calcium nutrition demonstrated which of the mechanisms in the calcium metabolism of trees are dependent on changes in element availability. Root labelling using the radioactive tracer 45Ca permitted aimed investigation of the uptake and translocation of calcium during shoot formation in May. The functional importance of the investigated nutritive element was characterized by breaking up the total calcium contents (45Ca) into the three essential chemical bonding forms (water-soluble Ca, Ca-pectate, Ca-oxalate) for the different tree fractions.- The culture experiments led to the conclusion that the root tips are most important as sites of calcium uptake. Translocation within the roots to the shoot took place via diffusion and exchange displacement as a function of calcium supply in the nutritive solution. There is no clue to support the assumption of a regulation of calcium uptake in spruces; in pines, by contrast, it cannot be excluded.- From a nutrition-physiological viewpoint, a total calcium content of 2 mg per gramme of dry mass is to be considered as sufficient. As this target is always attained, even where calcium supply is scarce, it is not appropriate to equate increased calcium availability with enhanced nutrient supply. Rather, the results discussed seem to support the theory that the trees now need to detoxicate excessively high calcium concentrations, which are liable to endanger the physiological cell metabolism, by a reaction with oxalic acid resulting in the formation of calcium oxalate. (orig.)