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Sample records for chemical calcium indicators

  1. Fluorescent indicator dyes for calcium ions

    Science.gov (United States)

    Tsien, Roger Y. (Inventor); Grynkiewicz, Grzegorz (Inventor)

    1986-01-01

    The present invention discloses a new class of highly fluorescent indicator dyes that are specific for calcium ions. The new fluorescent indicator dyes combine a stilbene-type fluorophore with a tetracarboxylate parent Ca.sup.2+ chelating compound having the octacoordinate pattern of liganding groups characteristic of EGTA and BAPTA. Preferred forms contain extra heterocyclic bridges to reinforce the ethylenic bond of the stilbene and to reduce hydrophobicity. Compared to their widely used predecessor, quin2, the new dyes offer up to thirty-fold brighter fluorescence, major changes in wavelength (not just intensity) upon Ca.sup.2+ binding, slightly lower affinities for Ca.sup.2+, slightly longer wavelengths of excitation, and considerably improved selectivity for Ca.sup.2+ over other divalent cations. These properties, particularly the wavelength sensitivity to Ca.sup.2+, make the dyes useful indicators for many intracellular applications, especially in single cells, adherent cell layers, or bulk tissues. The present invention also discloses an improved method for synthesizing alpha-acyloxyalkyl bromides wherein the bromides so synthesized are free of contaminating bis(1-bromoalkyl)ether. The improved method is exemplified herein in the synthesis of acetoxymethyl bromide, a compound useful in preparing the acetoxymethyl esters disclosed herein as novel Ca.sup.2+ specific fluorescent indicators.

  2. 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.

  3. Sensitive red protein calcium indicators for imaging neural activity.

    Science.gov (United States)

    Dana, Hod; Mohar, Boaz; Sun, Yi; Narayan, Sujatha; Gordus, Andrew; Hasseman, Jeremy P; Tsegaye, Getahun; Holt, Graham T; Hu, Amy; Walpita, Deepika; Patel, Ronak; Macklin, John J; Bargmann, Cornelia I; Ahrens, Misha B; Schreiter, Eric R; Jayaraman, Vivek; Looger, Loren L; Svoboda, Karel; Kim, Douglas S

    2016-01-01

    Genetically encoded calcium indicators (GECIs) allow measurement of activity in large populations of neurons and in small neuronal compartments, over times of milliseconds to months. Although GFP-based GECIs are widely used for in vivo neurophysiology, GECIs with red-shifted excitation and emission spectra have advantages for in vivo imaging because of reduced scattering and absorption in tissue, and a consequent reduction in phototoxicity. However, current red GECIs are inferior to the state-of-the-art GFP-based GCaMP6 indicators for detecting and quantifying neural activity. Here we present improved red GECIs based on mRuby (jRCaMP1a, b) and mApple (jRGECO1a), with sensitivity comparable to GCaMP6. We characterized the performance of the new red GECIs in cultured neurons and in mouse, Drosophila, zebrafish and C. elegans in vivo. Red GECIs facilitate deep-tissue imaging, dual-color imaging together with GFP-based reporters, and the use of optogenetics in combination with calcium imaging. PMID:27011354

  4. Calcium phosphate bioceramics prepared from wet chemically precipitated powders

    Directory of Open Access Journals (Sweden)

    Kristine Salma

    2010-03-01

    Full Text Available In this work calcium phosphates were synthesized by modified wet chemical precipitation route. Contrary to the conventional chemical precipitation route calcium hydroxide was homogenized with planetary mill. Milling calcium oxide and water in planetary ball mill as a first step of synthesis provides a highly dispersed calcium hydroxide suspension. The aim of this work was to study the influence of main processing parameters of wet chemical precipitation synthesis product and to control the morphology, phase and functional group composition and, consequently, thermal stability and microstructure of calcium phosphate bioceramics after thermal treatment. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions after thermal processing (hydroxyapatite [HAp], β-tricalcium phosphate [β-TCP] and HAp/β-TCP by modified wet-chemical precipitation route. The β-TCP phase content in sintered bioceramics samples is found to be highly dependent on the changes in technological parameters and it can be controlled with ending pH, synthesis temperature and thermal treatment. Pure, crystalline and highly thermally stable (up to 1300°C HAp bioceramics with homogenous grainy microstructure, grain size up to 200–250 nm and high open porosity can be successfully obtained by powder synthesized at elevated synthesis temperature of 70°C and stabilizing ending pH at 9.

  5. Quantitative Chemical Indices of Weathered Igneous Rocks

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A study was conducted to compare the effectiveness of different weathering indices for characterising weathered igneous rocks of Hong Kong. Among eight chemical indices evaluated in this study, the Parker index has been found most suitable for a quantitative description of state of weathering. Based on geochemical results of 174 samples, the index decreases almost linearly with an increasing extent of weathering. The results enable a better understanding of the modification of geotechnical properties of igneous rocks associated with weathering processes.

  6. Differential mitochondrial calcium responses in different cell types detected with a mitochondrial calcium fluorescent indicator, mito-GCaMP2

    Institute of Scientific and Technical Information of China (English)

    Min Chen; Yanru Wang; Tingting Hou; Huiliang Zhang; Aijuan Qu; Xianhua Wang

    2011-01-01

    Mitochondrial calcium plays a crucial role in mitochondriai metabolism,cell calcium handling,and cell death.However,some mechanisms concerning mitochondrial calcium regulation are still unknown,especially how mitochondrial calcium couples with cytosolic calcium.In this work,we constructed a novel mitochondrial calcium fluorescent indicator (mito-GCaMP2) by genetic manipulation.Mito-GCaMP2 was imported into mitochondria with high efficiency and the fluorescent signals co-localized with that of tetramethyl rhodamine methyl ester,a mitochondrial membrane potential indicator.The mitochondrial inhibitors specifically decreased the signals of mito-GCaMP2.The apparent Kd of mito-GCaMP2 was 195.0 nmol/L at pH 8.0 in adult rat cardiomyocytes.Furthermore,we observed that mito-GCaMP2 preferred the alkaline pH surrounding of mitochondria.In HeLa cells,we found that mitochondrial calcium ([Ca2+]mito)responded to the changes of cytosolic calcium ([Ca2+]cyto)induced by histamine or thapasigargin.Moreover,external Ca2+ (100 μmol/L) directly induced an increase of [Ca2+]mito in permeabilized HeLa cells.However,in rat cardiomyocytes [Ca2+]mito did not respond to cytosolic calcium transients stimulated by electric pacing or caffeine.In permeabilized cardiomyocytes,600 nmol/L free Ca2+ repeatedly increased the fluorescent signals of mito-GCaMP2,which excluded the possibility that mito-GCaMP2 lost its function in cardiomyocytes mitochondria.These results showed that the response of mitochondrial calcium is diverse in different cell lineages and suggested that mitochondria in cardiomyocytes may have a special defense mechanism to control calcium flux.

  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. Raman spectroscopic studies of chemical speciation in calcium chloride melts

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; Lavender, Curt A.

    2005-02-01

    Raman spectroscopy was applied to CaCl2 melts at 900 degrees C under both non-electrolyzed and electrolyzed conditions. The later used titania cathodes supplied by TIMET, Inc. and graphite anodes. Use of pulse-gating to collect the Raman spectra successfully eliminated any interference from black-body radiation and other stray light. The spectrum of molten CaCl2 exhibited no distinct, resolvable bands that could be correlated with a calcium chloride complex similar to MgCl42- in MgCl2 melts. Rather, the low frequency region of the spectrum was dominated by a broad “tail” arising from collective oscillations of both charge and mass in the molten salt “network.” Additions of both CaO and Ca at concentrations of a percent or two resulted in no new features in the spectra. Addition of CO2, both chemically and via electrolysis at concentrations dictated by stability and solubility at 900 degrees C and 1 bar pressure, also produced no new bands that could be correlated with either dissolved CO2 or the carbonate ion. These results indicated that Raman spectroscopy, at least under the conditions evaluated in the research, was not well suited for following the reactions and coordination chemistry of calcium ions, nor species such as dissolved metallic Ca and CO2 that are suspected to impact current efficiency in titanium electrolysis cells using molten CaCl2. Raman spectra of TIMET titania electrodes were successfully obtained as a function of temperature up to 900 degrees C, both in air and in-situ in CaCl2 melts. However, spectra of these electrodes could only be obtained when the material was in the unreduced state. When reduced, either with hydrogen or within an electrolysis cell, the resulting electrodes exhibited no measurable Raman bands under the conditions used in this work.

  9. Bulk loading of calcium indicator dyes to study astrocyte physiology: key limitations and improvements using morphological maps

    OpenAIRE

    Reeves, Alexander; Shigetomi, Eiji; Khakh, Baljit S.

    2011-01-01

    Calcium signalling has been studied in astrocyte cell bodies using bulk loading of calcium indicator dyes and astrocytes are known to display intracellular calcium transients. An assumption in recent data on the neuronal impact of somatic astrocyte calcium transients has been that bulk loading reflects signalling in relevant astrocyte compartments such as processes. We assessed bulk loading using Sholl analysis (Sholl, 1953) of astrocytes loaded with common calcium indicator dyes and compared...

  10. Effects of selenium, calcium and calcium ionophore on human oocytes in vitro maturation in a chemically defined medium

    OpenAIRE

    Hessam Roustaei; Mohammad Hasan Fallahian; Fatemeh Peyghambari; Raheleh Aram; Mohammad Ali Sabbaghi; Elham Saboori; Mehri Makki; Abbas Ahmadi

    2012-01-01

    Background: In vitro maturation (IVM) of human oocytes is an emerging procedure quickly incorporated into the world of assisted reproductive technologies. As an effective method of in vitro maturation, several studies have reported the critical role of differentions on activating the complex process involved in both gamete maturation and fertilization. Objective: In this study, we supplemented a chemically defined medium with different combinations of selenium, calcium and calcium ionophore c...

  11. A Validated Stability Indicating RP-UPLC Method for Atrovastain Calcium

    OpenAIRE

    Khagga Mukkanti; Maddala Vijaya Lakshmi; Chimalakonda Kameswara Rao; Kakumani Kishore Kumar

    2012-01-01

    The present paper describes stability indicating reverse phase Ultra performance liquid chromatographic (RPLC) assay method for Atrovastatin Calcium in bulk drugs. The developed method is also applicable for the related substance determination and degradation products generated from forced decomposition studies. The drug substance was subjected to stress conditions of acid hydrolysis, base hydrolysis, oxidation, photolysis and thermal degradation. The degradation of Atrovastatin was observed ...

  12. Preliminary Study on Chemical Components and Uranium Content of Calcium Fluoride Waste

    Institute of Scientific and Technical Information of China (English)

    LIANG; Xiao-hu; YANG; Lei; YANG; Jin-ling; SONG; Zhi-jun

    2013-01-01

    In the uranium conversion process,UF4 reduction is needed using calcium as reduction regent,so a great deal of calcium fluoride are generated,in which a no negligible amount of uranium(about 5%alleged)can be left in the calcium fluoride wastes by the entrainment effect.It is meaningful to extract and purify the uranium from these wastes,but chemical components of these waste is needed primarily.

  13. Constructing Global Production Activity Indices: The Chemical Industry

    OpenAIRE

    Saswati Mahapatra; Thomas K Swift

    2012-01-01

    This article first presents the challenges involved in constructing consistent, timely, and reliable short-term measures of national, regional, and global industry activity. The chemical industry is used as a case study. Second, this article presents the comparison of the movement or fluctuations in industrial production indices and chemical production indices that aid in determining if production in the chemical industry can be used as a proxy for total production in an economy. The American...

  14. Effect of chemical mixing state on the hygroscopicity and cloud nucleation properties of calcium mineral dust particles

    Directory of Open Access Journals (Sweden)

    R. C. Sullivan

    2009-05-01

    Full Text Available Atmospheric mineral dust particles can alter cloud properties and thus climate by acting as cloud condensation nuclei (CCN that form cloud droplets. The CCN activation properties of various calcium mineral dust particles were studied experimentally to investigate the consequences of field observations showing the segregation of sulphate from nitrate and chloride between individual aged Asian dust particles, and the enrichment of oxalic acid in Asian dust. Each mineral's observed apparent hygroscopicity was primarily controlled by its solubility, which determines the degree to which the mineral's intrinsic hygroscopicity can be expressed. The significant increase in hygroscopicity caused by mixing soluble hygroscopic material with insoluble mineral particles is also presented. Insoluble minerals including calcium carbonate, representing fresh unprocessed dust, and calcium sulphate, representing atmospherically processed dust, had similarly small apparent hygroscopicities. Their activation is accurately described by a deliquescence limit following the Kelvin effect and corresponded to an apparent single-hygroscopicity parameter, κ, of ~0.001. Soluble calcium chloride and calcium nitrate, representing atmospherically processed mineral dust particles, were much more hygroscopic, activating similar to ammonium sulphate with κ~0.5. Calcium oxalate monohydrate (κ=0.05 was significantly less CCN-active than oxalic acid (κ=0.3, but not as inactive as its low solubility would predict. These results indicate that the common assumption that all mineral dust particles become more hygroscopic and CCN-active after atmospheric processing should be revisited. Calcium sulphate and calcium oxalate are two realistic proxies for aged mineral dust that remain non-hygroscopic. The dust's apparent hygroscopicity will be controlled by its chemical mixing state, which is determined by its mineralogy and the chemical reaction pathways it experiences

  15. Effect of chemical mixing state on the hygroscopicity and cloud nucleation properties of calcium mineral dust particles

    Directory of Open Access Journals (Sweden)

    R. C. Sullivan

    2009-01-01

    Full Text Available Atmospheric mineral dust particles can alter cloud properties and thus climate by acting as cloud condensation nuclei (CCN that form cloud droplets. The CCN activation properties of various calcium mineral dust particles were studied experimentally to investigate the consequences of field observations showing the segregation of sulfate from nitrate and chloride between individual aged Asian dust particles, and the enrichment of oxalic acid in Asian dust. Each mineral's observed apparent hygroscopicity was primarily controlled by its solubility, which determines the degree to which the mineral's intrinsic hygroscopicity can be expressed. The significant increase in hygroscopicity caused by mixing soluble hygroscopic material with insoluble mineral particles is also presented. Insoluble minerals including calcium carbonate, representing fresh unprocessed dust, and calcium sulfate, representing atmospherically processed dust, had similarly small apparent hygroscopicities. Their activation is accurately described by a deliquescence limit following the Kelvin effect and corresponded to an apparent single-hygroscopicity parameter, κ, of ~0.001. Soluble calcium chloride and calcium nitrate, representing atmospherically processed mineral dust particles, were much more hygroscopic, activating similar to ammonium sulfate with κ~0.5. Calcium oxalate monohydrate (κ=0.05 was significantly less CCN-active than oxalic acid (κ=0.3, but not as inactive as its low solubility would predict. These results indicate that the common assumption that all mineral dust particles become more hygroscopic and CCN-active after atmospheric processing should be revisited. Calcium sulfate and calcium oxalate are two realistic proxies for aged mineral dust that remain non-hygroscopic. The dust's apparent hygroscopicity will be controlled by its chemical mixing state, which is determined by its mineralogy and the chemical reaction pathways it experiences during

  16. USE OF CHEMICAL INVENTORY ACCURACY MEASUREMENTS AS LEADING INDICATORS

    Energy Technology Data Exchange (ETDEWEB)

    Kuntamukkula, M.

    2011-02-10

    Chemical safety and lifecycle management (CSLM) is a process that involves managing chemicals and chemical information from the moment someone begins to order a chemical and lasts through final disposition(1). Central to CSLM is tracking data associated with chemicals which, for the purposes of this paper, is termed the chemical inventory. Examples of data that could be tracked include chemical identity, location, quantity, date procured, container type, and physical state. The reason why so much data is tracked is that the chemical inventory supports many functions. These functions include emergency management, which depends upon the data to more effectively plan for, and respond to, chemical accidents; environmental management that uses inventory information to aid in the generation of various federally-mandated and other regulatory reports; and chemical management that uses the information to increase the efficiency and safety with which chemicals are stored and utilized. All of the benefits of having an inventory are predicated upon having an inventory that is reasonably accurate. Because of the importance of ensuring one's chemical inventory is accurate, many have become concerned about measuring inventory accuracy. But beyond providing a measure of confidence in information gleaned from the inventory, does the inventory accuracy measurement provide any additional function? The answer is 'Yes'. It provides valuable information that can be used as a leading indicator to gauge the health of a chemical management system. In this paper, we will discuss: what properties make leading indicators effective, how chemical inventories can be used as a leading indicator, how chemical inventory accuracy can be measured, what levels of accuracies should realistically be expected in a healthy system, and what a subpar inventory accuracy measurement portends.

  17. Genetically encoded calcium indicators for multi-color neural activity imaging and combination with optogenetics

    OpenAIRE

    Akerboom, Jasper; Carreras Calderón, Nicole; Tian, Lin; Wabnig, Sebastian; Prigge, Matthias; Tolö, Johan; Gordus, Andrew; Orger, Michael B; Severi, Kristen E.; Macklin, John J.; Patel, Ronak; Pulver, Stefan R.; Trevor J Wardill; Fischer, Elisabeth; Schüler, Christina

    2013-01-01

    This work was supported by Goethe University Frankfurt; Deutsche Forschungsgemeinschaft (DFG), grant EXC115; European Union FP7 grant “EUTrigTreat and German Research Council (DFG) Grant MI 685/2-1. Genetically encoded calcium indicators (GECIs) are powerful tools for systems neuroscience. Here we describe red, single-wavelength GECIs, "RCaMPs," engineered from circular permutation of the thermostable red fluorescent protein mRuby. High-resolution crystal structures of mRuby, the red senso...

  18. Performance indicators for monitoring safety management systems in chemical industry

    Directory of Open Access Journals (Sweden)

    M. Jovašević-Stojanović

    2009-01-01

    Full Text Available The development of the Safety Management System (SMS in chemical industry appears as one of the important requirements introduced by the EU "Seveso II" Directive on the control of major-accident hazards. This paper aims to provide a contribution regarding the SMS structure and the definition of the tools for assessing the effectiveness of this system by means of safety performance indicators. The performance indicators are linked to a reference values or policy targets, illustrating how far the SMS is from the desired level. We developed a system of performance indicators for SMS in chemical industry by using the concept of environmental performance indicators defined in standard ISO 14031. A set of three types of safety system performance indicators was proposed: management performance indicators, operational performance indicators and safety status indicators. These indicators represent the most important factors in the linkage between a possible cause of an accident and its effects.

  19. Extended phase homogeneity and electrical properties of barium calcium titanate prepared by the wet chemical methods

    International Nuclear Information System (INIS)

    Ca-substituted BaTiO3 with extended homogeneity range upto ∼50 mol% CaTiO3 have been prepared by three different chemical routes namely carbonate-oxalate (COBCT), gel-carbonate (GCBCT), and gel-to-crystallite conversion (GHBCT) followed by heat treatment above 1150 deg. C. X-ray powder diffraction (XRD) data show continuous decrease in the tetragonal unit cell parameters as well as c0/a0 ratio with CaTiO3 content, which are in accordance with the substitution of smaller sized Ca2+ ions at the barium sites. The microstructure as well as the dielectric properties are greatly influenced by the cationic ratio, α=(Ba+Ca)/Ti. The grain size decreases with CaTiO3 content for the stoichiometric samples (α=1), whereas ultrafine microstructure is observed in the case of off-stoichiometric samples (α>1) for the whole compositional range of CaTiO3 concentrations. Sharper εr-T characteristics at lower calcium content and broader εr-T with decreased εmax, in the higher calcium range are observed in the case of α=1. Whereas nanometer grained ceramics exhibiting diffuse εr-T characteristics are obtained in the case of α>1. The positive temperature coefficient of resistivity (PTCR) is realized for barium calcium titanate ceramics having 0.3 at.% Sb as the donor dopant for higher CaTiO3 (typically 30 mol%) containing samples (α=1), indicating that Ca2+ ions do not behave as acceptors if they were to substitute at the Ti4+ sites. Whereas the off-stoichiometric (α>1) ceramics retained high resistivity, indicative of the Ti-site occupancy for Ca2+ in fine grain ceramics

  20. 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.

  1. A neuron-based screening platform for optimizing genetically-encoded calcium indicators.

    Directory of Open Access Journals (Sweden)

    Trevor J Wardill

    Full Text Available Fluorescent protein-based sensors for detecting neuronal activity have been developed largely based on non-neuronal screening systems. However, the dynamics of neuronal state variables (e.g., voltage, calcium, etc. are typically very rapid compared to those of non-excitable cells. We developed an electrical stimulation and fluorescence imaging platform based on dissociated rat primary neuronal cultures. We describe its use in testing genetically-encoded calcium indicators (GECIs. Efficient neuronal GECI expression was achieved using lentiviruses containing a neuronal-selective gene promoter. Action potentials (APs and thus neuronal calcium levels were quantitatively controlled by electrical field stimulation, and fluorescence images were recorded. Images were segmented to extract fluorescence signals corresponding to individual GECI-expressing neurons, which improved sensitivity over full-field measurements. We demonstrate the superiority of screening GECIs in neurons compared with solution measurements. Neuronal screening was useful for efficient identification of variants with both improved response kinetics and high signal amplitudes. This platform can be used to screen many types of sensors with cellular resolution under realistic conditions where neuronal state variables are in relevant ranges with respect to timing and amplitude.

  2. Preparation and characterization of calcium aluminate by chemical synthesis

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Saturated Ca(OH)2 and AlCl3 solutions were used to synthesize calcium aluminate hydrate precipitates at room temperature; high purity calcium aluminate powders with stable phases were made by calcination of the precursors at a temperature as low as1100℃. PSD and BET analysis revealed the particles with sizes ranging from submicrometer to several micrometers and with a specific area of 13 m2/g. The measurement of hydraulic exotherm revealed that the exothermal rate is in peak for about 2 h. The exothermal quantities are 449.24 J/g at 12 h and 488.38 J/g at 24 h. Its strength development is quick and the 1 day curing strength is almost equal to 100% of the 3 days curing strength in the mortar test.

  3. Genetically encoded calcium indicators for multi-color neural activity imaging and combination with optogenetics

    Directory of Open Access Journals (Sweden)

    Jasper eAkerboom

    2013-03-01

    Full Text Available Genetically encoded calcium indicators (GECIs are powerful tools for systems neuroscience. Here we describe red, single-wavelength GECIs, RCaMPs, engineered from circular permutation of the thermostable red fluorescent protein mRuby. High-resolution crystal structures of mRuby, the red sensor RCaMP, and the recently published red GECI R-GECO1 give insight into the chromophore environments of the Ca2+-bound state of the sensors and the engineered protein domain interfaces of the different indicators. We characterized the biophysical properties and performance of RCaMP sensors in vitro and in vivo in Caenorhabditis elegans, Drosophila larvae, and larval zebrafish. Further, we demonstrate 2-color calcium imaging both within the same cell (registering mitochondrial and somatic [Ca2+] and between two populations of cells: neurons and astrocytes. Finally, we perform integrated optogenetics experiments, wherein neural activation via channelrhodopsin-2 (ChR2 or a red-shifted variant, and activity imaging via RCaMP or GCaMP, are conducted simultaneously, with the ChR2/RCaMP pair providing independently addressable spectral channels. Using this paradigm, we measure calcium responses of naturalistic and ChR2-evoked muscle contractions in vivo in crawling C. elegans. We systematically compare the RCaMP sensors to R-GECO1, in terms of action potential-evoked fluorescence increases in neurons, photobleaching, and photoswitching. R-GECO1 displays higher Ca2+ affinity and larger dynamic range than RCaMP, but exhibits significant photoactivation with blue and green light, suggesting that integrated channelrhodopsin-based optogenetics using R-GECO1 may be subject to artifact. Finally, we create and test blue, cyan and yellow variants engineered from GCaMP by rational design. This engineered set of chromatic variants facilitates new experiments in functional imaging and optogenetics.

  4. Bioactive calcium phosphate coating formed on micro-arc oxidized magnesium by chemical deposition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, G.Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Hu, J., E-mail: hujin@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ding, Z.K.; Wang, C. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2011-01-01

    In order to improve the bioactivity of the micro-arc oxidized magnesium, a calcium phosphate coating was formed on the surface of micro-arc oxidized magnesium using a chemical method. The microstructures of the substrate and the calcium phosphate coating before and after the simulated body fluids (SBF) incubation were characterized by X-ray diffraction, Fourier-transformed infrared spectroscopy and scanning electron microscopy. The results showed that the calcified coating was composed of calcium deficient hydroxyapatite (HA) and dicalcium phosphate dihydrate (DCPD). After SBF incubation, some new apatite formation on the calcified coating surface from SBF could be found. The corrosion behaviours of the samples in SBF were also investigated by potentiodynamic polarization curves and immersion tests. The results showed that calcium phosphate coating increased the corrosion potential, and decreased the hydrogen gas release.

  5. Comparing wastewater chemicals, indicator bacteria concentrations, and bacterial pathogen genes as fecal pollution indicators

    Science.gov (United States)

    Haack, S.K.; Duris, J.W.; Fogarty, L.R.; Kolpin, D.W.; Focazio, M.J.; Furlong, E.T.; Meyer, M.T.

    2009-01-01

    The objective of this study was to compare fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli [EC], and enterococci [ENT]) concentrations with a wide array of typical organic wastewater chemicals and selected bacterial genes as indicators of fecal pollution in water samples collected at or near 18 surface water drinking water intakes. Genes tested included esp (indicating human-pathogenic ENT) and nine genes associated with various animal sources of shiga-toxin-producing EC (STEC). Fecal pollution was indicated by genes and/or chemicals for 14 of the 18 tested samples, with little relation to FIB standards. Of 13 samples with genes (indicating varying animal sources of STEC) were detected in eight. Only the EC eaeA gene was positively correlated with FIB concentrations. Human-source fecal pollution was indicated by the esp gene and the human pharmaceutical carbamazepine in one of the nine samples that met all FIB recreational water quality standards. Escherichia coli rfbO157 and stx2c genes, which are typically associated with cattle sources and are of potential human health significance, were detected in one sample in the absence of tested chemicals. Chemical and gene-based indicators of fecal contamination may be present even when FIB standards are met, and some may, unlike FIB, indicate potential sources. Application of multiple water quality indicators with variable environmental persistence and fate may yield greater confidence in fecal pollution assessment and may inform remediation decisions. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  6. Selection and Evaluation of Chemical Indicators for Waste Stream Identification

    Science.gov (United States)

    DeVita, W. M.; Hall, J.

    2015-12-01

    Human and animal wastes pose a threat to the quality of groundwater, surface water and drinking water. This is especially of concern for private and public water supplies in agricultural areas of Wisconsin where land spreading of livestock waste occurs on thin soils overlaying fractured bedrock. Current microbial source tracking (MST) methods for source identification requires the use of polymerase chain reaction (PCR) techniques. Due to cost, these tests are often not an option for homeowners, municipalities or state agencies with limited resources. The Water and Environmental Analysis Laboratory sought to develop chemical methods to provide lower cost processes to determine sources of fecal waste using fecal sterols, pharmaceuticals (human and veterinary) and human care/use products in ground and surface waters using solid phase extraction combined with triple quadrupole mass spectrometry. The two separate techniques allow for the detection of fecal sterol and other chemical markers in the sub part per billion-range. Fecal sterol ratios from published sources were used to evaluate drinking water samples and wastewater from onsite waste treatment systems and municipal wastewater treatment plants. Pharmaceuticals and personal care products indicative of human waste included: acetaminophen, caffeine, carbamazepine, cotinine, paraxanthine, sulfamethoxazole, and the artificial sweeteners; acesulfame, saccharin, and sucralose. The bovine antibiotic sulfamethazine was also targeted. Well water samples with suspected fecal contamination were analyzed for fecal sterols and PPCPs. Results were compared to traditional MST results from the Wisconsin State Laboratory of Hygiene. Chemical indicators were found in 6 of 11 drinking water samples, and 5 of 11 were in support of MST results. Lack of detection of chemical indicators in samples contaminated with fecal waste supports the need for confirmatory methods and advancement of chemical indicator detection technologies.

  7. Provenance control on chemical indices of weathering (Taiwan river sands)

    Science.gov (United States)

    Garzanti, Eduardo; Resentini, Alberto

    2016-05-01

    Geochemical parameters obtained from the analysis of sediments and sedimentary rocks are widely used to infer weathering and paleo-weathering conditions in source areas. Chemical indices of weathering, however, may not reflect weathering only, or even principally. The concentration of chemical elements in terrigenous sediments is constrained by the original mineralogy of source rocks, and is thus provenance-dependent. Moreover, the mineralogy and consequently the geochemistry of sediments may undergo substantial modifications by diverse physical processes during transport and deposition, including recycling and hydraulic sorting by size, density or shape, and/or by chemical dissolution and precipitation during diagenesis. Around the island of Taiwan, temperature and rainfall are consistently high and relatively homogeneous, and no significant correlation is observed between geochemical and climatic parameters. Physical erosion, fostered by landslides induced by frequent earthquakes and typhoons, prevails because of high relief and extreme rates of tectonic uplift. In such a dynamic orogenic setting, all chemical indices of weathering are controlled principally by the geology of source terranes. Sedimentaclastic and metasedimentaclastic sands carried by western Taiwan rivers draining the pro-wedge display the strongest depletion in Na, Ca, Mg and Sr relative to average upper continental crust, and no depletion or even enrichment in K, Rb and Ba. Low WIP indices reflect erosion of phyllosilicate-dominated rocks in the Slate Belt and extensive recycling of clastic rocks exposed in the Western Foothills. Instead, metamorphiclastic sands carried by eastern Taiwan rivers draining the retro-wedge show no depletion or even enrichment in Mg and Ca, and low CIA and PIA, reflecting contributions from the Tailuko Belt and Coastal Range. Volcaniclastic sands have the same CIA values of their andesitic source rocks (47 ± 1 versus 47 ± 7), indicating that weathering is

  8. 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.

  9. Use of calcium/aluminum ratios as indicators of stress in forest ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Cronan, C.S. [Univ. of Maine, Orono, ME (United States); Grigal, D.F. [Univ. of Minnesota, St. Paul, MN (United States)

    1995-03-01

    The calcium/aluminum (Ca/Al) molar ratio of the soil solution provides a valuable measurement endpoint or ecological indicator for identification of approximate thresholds beyond which the risk of forest damage from Al stress and nutrient imbalances increases. The Ca/Al ratio can also be used as an indicator to assess forest ecosystem changes over time in response to acidic deposition, forest harvesting, or other processes contributing to acid soil infertility. Based on a critical review of literature on Al stress, we estimate that there is a 50:50 risk of adverse impacts on tree growth or nutrition when the soil solution Ca/Al ratio is as low as 1.0, a 75% risk when the soil solution ratio is as low as 0.5, and nearly a 100% risk when the soil solution Ca/Al molar ratio is as low as 0.2. The Ca/Al ratio of the soil solution can be corroborated with other complementary indices.

  10. Physical and chemical properties of fish and chicken bones as calcium source for mineral supplements

    Directory of Open Access Journals (Sweden)

    Worapot Suntornsuk

    2006-03-01

    Full Text Available Physical and chemical properties of two bones of two species of fish, hoki (Macruronus novaezelandiae and giant seaperch (Lates calcarifer Bloch., were compared with chicken bone to evaluate their composition for use as natural calcium supplement. The information could be useful for waste utilization in the food and pharmaceutical industries. Physical testing and chemical analyses were performed according to the USP 24 and BP 1998 standards under calcium carbonate monograph. Loss on drying found in hoki, giant seaperch and chicken bones was 12.4, 11.3 and 5.9 % w/w, calculated on dried basis, respectively. Total calcium determined by complexometric titration was 31.8, 28.1 and 32.2% w/w in hoki, giant seaperch and chicken bones, respectively. All samples contained carbonate and phosphate anion residues but gluconate, acetate and citrate were absent. The presence of calcium carbonate was confirmed by thermogravimetry. Results from all bones showed that limit tests for heavy metals, arsenic and iron complied with the USP standard, whereas barium, chloride and sulfate conformed to the BP standard. The magnesium and alkali metals in giant seaperch bone were within the BP limit (1.5%, but those of hoki and chicken bone exceeded the limit.

  11. Imaging activity in astrocytes and neurons with genetically encoded calcium indicators following in utero electroporation.

    Science.gov (United States)

    Gee, J Michael; Gibbons, Meredith B; Taheri, Marsa; Palumbos, Sierra; Morris, S Craig; Smeal, Roy M; Flynn, Katherine F; Economo, Michael N; Cizek, Christian G; Capecchi, Mario R; Tvrdik, Petr; Wilcox, Karen S; White, John A

    2015-01-01

    Complex interactions between networks of astrocytes and neurons are beginning to be appreciated, but remain poorly understood. Transgenic mice expressing fluorescent protein reporters of cellular activity, such as the GCaMP family of genetically encoded calcium indicators (GECIs), have been used to explore network behavior. However, in some cases, it may be desirable to use long-established rat models that closely mimic particular aspects of human conditions such as Parkinson's disease and the development of epilepsy following status epilepticus. Methods for expressing reporter proteins in the rat brain are relatively limited. Transgenic rat technologies exist but are fairly immature. Viral-mediated expression is robust but unstable, requires invasive injections, and only works well for fairly small genes (option of co-expressing a cytosolic tdTomato protein. A binary system consisting of a plasmid carrying a piggyBac inverted terminal repeat (ITR)-flanked CAG-GCaMP-IRES-tdTomato cassette and a separate plasmid encoding for expression of piggyBac transposase was employed to stably express GCaMP and tdTomato. The plasmids were co-electroporated on embryonic days 13.5-14.5 and astrocytic and neuronal activity was subsequently imaged in acute or cultured brain slices prepared from the cortex or hippocampus. Large spontaneous transients were detected in slices obtained from rats of varying ages up to 127 days. In this report, we demonstrate the utility of this toolset for interrogating astrocytic and neuronal activity in the rat brain. PMID:25926768

  12. Properties of Chemically Combusted Calcium Carbide Residue and Its Influence on Cement Properties

    OpenAIRE

    Hongfang Sun; Zishanshan Li; Jing Bai; Shazim Ali Memon; Biqin Dong; Yuan Fang; Weiting Xu; Feng Xing

    2015-01-01

    Calcium carbide residue (CCR) is a waste by-product from acetylene gas production. The main component of CCR is Ca(OH)2, which can react with siliceous materials through pozzolanic reactions, resulting in a product similar to those obtained from the cement hydration process. Thus, it is possible to use CCR as a substitute for Portland cement in concrete. In this research, we synthesized CCR and silica fume through a chemical combustion technique to produce a new reactive cementitious powder (...

  13. Chemical stabilization of mine waste with sewage sludge and calcium carbonate residues

    OpenAIRE

    Höckert, Linda

    2007-01-01

    Chemical stabilization of mine waste from Ljusnarsbergsfältet with sewage sludge and calcium carbonate residues Mine waste from Ljusnarsbergsfältet in Kopparberg, Sweden, is considered to constitute a great risk for human health and the surrounding environment. Some of the waste rock consists of sulphide minerals. When sulphide minerals come into contact with dissolved oxygen and precipitation, oxidation may occur resulting in acid mine drainage (AMD) and the release of heavy metals. The purp...

  14. OPTIMIZATION OF CHEMICALS USE FOR HIGHLY FILLED MECHANICAL GRADE PAPERS WITH PRECIPITATED CALCIUM CARBONATE

    OpenAIRE

    Yizhou Sang,; Michael McQuaid; Peter Englezos

    2011-01-01

    Response surface methodology was used with four factors to screen for the best starch and optimize the use of chemicals in order to maximize precipitated calcium carbonate (PCC) filler retention in a peroxide-bleached TMP suspension. Three commercial starches were used in conjunction with colloidal silica and flocculant. The PCC loading level and the interactions between PCC level, starch, flocculant, and silica were investigated, and empirical models were constructed. The empirical process m...

  15. Integration of calcium and chemical looping combustion using composite CaO/CuO-based materials.

    Science.gov (United States)

    Manovic, Vasilije; Anthony, Edward J

    2011-12-15

    Calcium looping cycles (CaL) and chemical looping combustion (CLC) are two new, developing technologies for reduction of CO(2) emissions from plants using fossil fuels for energy production, which are being intensively examined. Calcium looping is a two-stage process, which includes oxy-fuel combustion for sorbent regeneration, i.e., generation of a concentrated CO(2) stream. This paper discuss the development of composite materials which can use copper(II)-oxide (CuO) as an oxygen carrier to provide oxygen for the sorbent regeneration stage of calcium looping. In other words, the work presented here involves integration of calcium looping and chemical looping into a new class of postcombustion CO(2) capture processes designated as integrated CaL and CLC (CaL-CLC or Ca-Cu looping cycles) using composite pellets containing lime (CaO) and CuO together with the addition of calcium aluminate cement as a binder. Their activity was tested in a thermogravimetric analyzer (TGA) during calcination/reduction/oxidation/carbonation cycles. The calcination/reduction typically was performed in methane (CH(4)), and the oxidation/carbonation stage was carried out using a gas mixture containing both CO(2) and O(2). It was confirmed that the material synthesized is suitable for the proposed cycles; with the very favorable finding that reduction/oxidation of the oxygen carrier is complete. Various schemes for the Ca-Cu looping process have been explored here that would be compatible with these new composite materials, along with some different possibilities for flow directions among carbonator, calciner, and air reactor. PMID:22022778

  16. TEMPERATURE MEASUREMENT OF REFLECTED SHOCK WAVE BY USING CHEMICAL INDICATOR

    Institute of Scientific and Technical Information of China (English)

    Cui Jiping; He Yuzhong; Wang Su; Wang Jing; Fan Bingcheng

    2000-01-01

    This report describes a new method for measuring the temperature of the gas behind the reflected shock wave in shock tube,corresponding to the reservoir temperature of a shock tunnel,based on the chemical reaction of small amount of CF4 premixed in the test gas.The final product C2F4 is used as the temperature indicator,which is sampled and detected by a gas chromatography in the experiment.The detected concentration of C2F4 is correlated to the temperature of the reflected shock wave with the initial pressure P1 and test time γas parameters in the temperature range 3300K<T<5600K,pressure range 5kPa<P1<12kPa andγ≈0.4ms.

  17. Bioluminescent bacteria as indicators of chemical contamination of coastal waters.

    Science.gov (United States)

    Frischer, M E; Danforth, J M; Foy, T F; Juraske, R

    2005-01-01

    The ratio of bioluminescent to total bacteria (bioluminescent ratio, BLR) as an indicator of a variety of types of anthropogenic contamination of estuarine ecosystems was evaluated through a series of laboratory and field studies. Laboratory studies indicated that the BLR of natural bacterioplankton communities was proportionally reduced in the presence of a number of contaminants including diesel fuel and saltmarsh sediments co-contaminated with mercury and polychlorinated biphenyls (PCBs). Bioluminescent ratio inhibition was observed after short-term exposure to a contaminant suggesting a physiological rather than a population response of native microbial communities. Simulated eutrophication did not suppress the BLR. Field observations of the BLR were conducted weekly for a 2-yr period in the Skidaway River estuary, Georgia, USA. These observations revealed considerable seasonal variability associated with the BLR. Bioluminescent ratios were highest during the summer (25 +/- 15%), lower in the fall (6 +/- 5%) and spring (3 +/- 2%), and near zero during the winter. Although the BLR was not significantly correlated to salinity at a single site (Skidaway River estuary), the BLR was significantly correlated with salinity when sites within the same estuary system were compared (r2 = 0.93). Variation in BLR was not correlated to standard bacteriological indicators of water quality including total and fecal coliform bacteria. Comparison of the BLR from impacted and pristine estuarine sites during the fall suggested that anthropogenically impacted sites exhibited lower BLR than predicted from salinity versus BLR relationships developed in pristine systems. These observations suggest that the BLR could be used as a simple and reliable initial indicator of chemical contamination of estuarine systems resulting from human activity. PMID:15998855

  18. A Reassessment of Complementary Access Tools for Chemical Indicators

    Energy Technology Data Exchange (ETDEWEB)

    Siskind, Barry [Brookhaven National Lab. (BNL), Upton, NY (United States). Nonproliferation and National Security Dept.; Stern, Warren [Brookhaven National Lab. (BNL), Upton, NY (United States). Nonproliferation and National Security Dept.; Henzl, Vladimir [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-01

    The Complementary Access Working Group (CAWG) was set up as a multi-laboratory team with members from Brookhaven National Laboratory (BNL), Idaho National Laboratory (INL), Los Alamos National Laboratory (LANL), and Sandia National Laboratories (SNL) under the direction and funding provided by National Nuclear Security Administration (NNSA) through NA-241, Next Generation Safeguards Initiative (NGSI). During FY 13 the CAWG evaluated proliferation indicators based largely on a review of the 1996 version of the IAEA’s Physical Model (Phase 1). During FYs 13 and 14, the CAWG then selected technologies and specific portable and hand-held devices that could be used by the IAEA to identify the chemical compositions of materials found during complementary access (Phase 2). [Note that in this report “chemical” is used in a broad sense to include elements, metals, and alloys as well as chemical compounds.] In November 2014, the CAWG issued its Phase 3 report describing laboratory and field testing of three devices, each device representing a specific technology that the CAWG had selected as a result of the Phase 1 and Phase 2 activities. LANL and BNL continued measurements and analysis during FY15, leading to a reinterpretation of some of the Phase 3 results. This report serves a twofold purpose. The first section of the report compares and contrasts the Phase 3 testing with presently available preliminary results of the Karlsruhe workshop. The results of Phase 3 (and the reinterpretation of some of these results) as well as the preliminary results of the Karlsruhe workshop provide the rationale for the second section of this report. In Section 2 of this report, we revisit the combinations of signatures and technologies considered in Phases 2 and 3 of the CAWG effort. We do this to determine whether the three technologies and the matching instruments selected for the Phase 3 testing are more limited than initially thought. Based on this initial re-evaluation of the

  19. The chemical transformation of calcium in Shenhua coal during combustion in a muffle furnace

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Sida [North China Electric Power Univ., Beijing (China). School of Energy, Power and Mechanical Engineering; Ministry of Education, Beijing (China). Key Lab. of Condition Monitoring and Control for Power Plant Equipment; Zhuo, Yuqun; Chen, Changhe [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering; Ministry of Education, Beijing (China). Key Lab. for Thermal Science and Power Engineering; Shu, Xinqian [China Univ. of Mining and Technology, Beijing (China). School of Chemical and Environmental Engineering

    2013-07-01

    The chemical reaction characteristics of calcium in three samples of Shenhua coal, i.e. raw sample, hydrochloric acid washed sample and hydrochloric acid washed light fraction, during combustion in a muffle furnace have been investigated in this paper. Ca is bound by calcite and organic matter in Shenhua coal. X ray diffraction (XRD) phase analysis has been conducted to these samples' combustion products obtained by heating at different temperatures. It has been found that the organically-bound calcium could easily react with clays and transform into gehlenite and anorthite partially if combusted under 815 C, whilst the excluded minerals promoted the conversion of gehlenite to anorthite. Calcite in Shenhua coal decomposed into calcium oxide and partially transformed into calcium sulfate under 815 C, and formed gehlenite and anorthite under 1,050 C. Calcite and other HCl-dissolved minerals in Shenhua coal were responsible mainly for the characteristic that the clay minerals in Shenhua coal hardly became mullite during combustion.

  20. An amplified promoter system for targeted expression of calcium indicator proteins in the cerebellar cortex

    Directory of Open Access Journals (Sweden)

    Bernd eKuhn

    2012-07-01

    Full Text Available Recording of identified neuronal network activity using genetically encoded calcium indicators (GECIs requires labeling that is cell type-specific and bright enough for the detection of functional signals. However, specificity and strong expression are often not achievable using the same promoter. Here we present a combinatorial approach for targeted expression and single-cell-level quantification in which a weak promoter is used to drive trans-amplification under a strong general promoter. We demonstrated this approach using recombinant adeno-associated viruses (rAAVs to deliver the sequence of the GECI D3cpv in the mouse cerebellar cortex. Direct expression under the human synapsin promoter (hSYN led to high levels of expression (50-100 µM in five interneuron types of the cerebellar cortex but not in Purkinje cells (PCs (≤10 μM, yielding sufficient contrast to allow functional signals to be recorded from somata and processes in awake animals using two-photon microscopy. When the hSYN promoter was used to drive expression of the tetracycline transactivator (tTA, a second rAAV containing the bidirectional TET promoter (Ptetbi could drive strong D3cpv expression in PCs (10-300 µM, enough to allow reliable complex spike detection in the dendritic arbor. An amplified approach should be of use in monitoring neural processing in selected cell types and boosting expression of optogenetic probes. Additionally, we overcome cell toxicity associated with rAAV injection and/or local GECI overexpression by combining the virus injection with systemic pre-injection of hyperosmotic D-mannitol, and by this double the time window for functional imaging.

  1. Imaging activity in astrocytes and neurons with genetically encoded calcium indicators following in utero electroporation

    Directory of Open Access Journals (Sweden)

    J. Michael eGee

    2015-04-01

    Full Text Available Complex interactions between networks of astrocytes and neurons are beginning to be appreciated, but remain poorly understood. Transgenic mice expressing fluorescent protein reporters of cellular activity, such as the GCaMP family of genetically encoded calcium indicators, have been used to explore network behavior. However, in some cases, it may be desirable to use long-established rat models that closely mimic particular aspects of human conditions such as Parkinson’s disease and the development of epilepsy following status epilepticus. Methods for expressing reporter proteins in the rat brain are relatively limited. Transgenic rat technologies exist but are fairly immature. Viral-mediated expression is robust but unstable, requires invasive injections, and only works well for fairly small genes (< 5 kb. In utero electroporation offers a valuable alternative. IUE is a proven method for transfecting populations of astrocytes and neurons in the rat brain without the strict limitations on transgene size. We built a toolset of IUE plasmids carrying GCaMP variants 3, 6s or 6f driven by CAG and targeted to the cytosol or the plasma membrane. Because low baseline fluorescence of GCaMP can hinder identification of transfected cells, we included the option of co-expressing a cytosolic tdTomato protein. A binary system consisting of a plasmid carrying a piggyBac inverted terminal repeat-flanked CAG-GCaMP-IRES-tdTomato cassette and a separate plasmid encoding for expression of piggyBac transposase was employed to stably express GCaMP and tdTomato. The plasmids were co-electroporated on embryonic days 13.5-14.5 and astrocytic and neuronal activity was subsequently imaged in acute or cultured brain slices prepared from the cortex or hippocampus. Large spontaneous transients were detected in slices obtained from rats of varying ages up to 127 days. In this report, we demonstrate the utility of this toolset for interrogating astrocytic and neuronal

  2. Chemical surface modification of calcium carbonate particles with stearic acid using different treating methods

    Science.gov (United States)

    Cao, Zhi; Daly, Michael; Clémence, Lopez; Geever, Luke M.; Major, Ian; Higginbotham, Clement L.; Devine, Declan M.

    2016-08-01

    Calcium carbonate (CaCO3) is often treated with stearic acid (SA) to decrease its polarity. However, the method of application of the SA treatments has a strong influence on CaCO3 thermoplastic composite's interfacial structure and distribution. Several of papers describe the promising effects of SA surface treatment, but few compare the treatment process and its effect on the properties of the final thermoplastic composite. In the current study, we assessed a new SA treatment method, namely, complex treatment for polymer composite fabrication with HDPE. Subsequently, a comparative study was performed between the "complex" process and the other existing methods. The composites were assessed using different experiments included scanning electron microscopy (SEM), void content, density, wettability, differential scanning calorimetry (DSC), and tensile tests. It was observed that the "complex" surface treatment yielded composites with a significantly lower voids content and higher density compared to other surface treatments. This indicates that after the "complex" treatment process, the CaCO3 particles and HDPE matrix are more tightly packed than other methods. DSC and wettability results suggest that the "wet" and "complex" treated CaCO3 composites had a significantly higher heat of fusion and moisture resistance compared to the "dry" treated CaCO3 composites. Furthermore, "wet" and "complex" treated CaCO3 composites have a significantly higher tensile strength than the composites containing untreated and "dry" treated CaCO3. This is mainly because the "wet" and "complex" treatment processes have increased adsorption density of stearate, which enhances the interfacial interaction between matrix and filler. These results confirm that the chemical adsorption of the surfactant ions at the solid-liquid interface is higher than at other interface. From this study, it was concluded that the utilization of the "complex" method minimised the negative effects of void

  3. ZrO2 thin films to improve the chemical resistance of calcium matt glazes

    International Nuclear Information System (INIS)

    The chemical resistance of ceramic glazes susceptible to it, and more specifically the glazes formulated with a calcium matt frit, is enhanced by depositing on the surface a thin layer of zirconium oxide. A stabilized zirconia sol is the precursor of the layer, which is deposited by spray painting over the glaze, and with a mild heat treatment (Tmax ∼∼ 400 degree centigrade) is transformed into ZrO2 and anchored to the glazes surface. Chemical resistance tests show that the protected glaze does not suffer a visually significant attack by concentrated hydrochloric acid, conditions under which the same glaze without the coating is severely damaged. The used precursor generates a zirconium oxide layer that protects the underlying glaze, so that the chemical attack by the hydrochloric acid is confined to cracks and discontinuities in the deposited layer. (Author) 22 refs.

  4. Sustainability Indicators for Chemical Processes: III. Biodiesel Case Study

    Science.gov (United States)

    The chemical industry is one of the most important business sectors, not only economically, but also societally; as it allows humanity to attain higher standards and quality of life. Simultaneously, chemical products and processes can be the origin of potential human health and ...

  5. Chemical composition and dry matter digestibility of sugar cane oxide treated with calcium

    OpenAIRE

    C.O. Romão; G.G.P. Carvalho; V.M. Leite; Santos, A. S.; D.M.T. Chagas; O.L. Ribeiro; P.A. Oliveira; Magalhães, A F; A.J.V. Pires

    2014-01-01

    The aim of this study was to identify the most adequate level of calcium oxide (CaO) in the treatment of sugar cane by evaluating the chemical composition and in vitro digestibility of dry matter. The sugar cane was homogenized with CaO levels 0, 0.75, 1.5, 2.25, 3.0, 3.75 and 4.5%, in natura matter, for 24 hours. The dry matter and mineral matter increased, while the organic matter of the sugar cane decreased (P

  6. Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer

    OpenAIRE

    KUGA, Milton Carlos; DUARTE Marco Antonio Hungaro; SANT'ANNA-JÚNIOR, Arnaldo; KEINE, Kátia Cristina; FARIA, Gisele; Andrea Abi Rached DANTAS; GUIOTTI, Flávia Angélica

    2014-01-01

    Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. Objective: The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF) or containing 5% (MTAF5) or 10% (MTAF10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer. Material and Methods: The...

  7. Genetic visualization with an improved GCaMP calcium indicator reveals spatiotemporal activation of the spinal motor neurons in zebrafish

    OpenAIRE

    Muto, Akira; Ohkura, Masamichi; Kotani, Tomoya; Higashijima, Shin-ichi; Nakai, Junichi; Kawakami, Koichi

    2011-01-01

    Animal behaviors are generated by well-coordinated activation of neural circuits. In zebrafish, embryos start to show spontaneous muscle contractions at 17 to 19 h postfertilization. To visualize how motor circuits in the spinal cord are activated during this behavior, we developed GCaMP-HS (GCaMP-hyper sensitive), an improved version of the genetically encoded calcium indicator GCaMP, and created transgenic zebrafish carrying the GCaMP-HS gene downstream of the Gal4-recognition sequence, UAS...

  8. A Chemical Template for Synthesis of Molecular Sheets of Calcium Carbonate.

    Science.gov (United States)

    Rianasari, Ina; Benyettou, Farah; Sharma, Sudhir Kumar; Blanton, Thomas; Kirmizialtin, Serdal; Jagannathan, Ramesh

    2016-01-01

    Inspired by the discovery of graphene and its unique properties, we focused our research to develop a scheme to create nacre like lamellar structures of molecular sheets of CaCO3 interleaved with an organic material, namely carbon. We developed a facile, chemical template technique, using a formulation of poly(acrylic) acid (PAA) and calcium acetate to create lamellar stacks of single crystal sheets of CaCO3, with a nominal thickness of 17 Å, the same as a unit-cell dimension for calcite (c-axis = 17.062 Å), interleaved with amorphous carbon with a nominal thickness of 8 Å. The strong binding affinity between carboxylate anions and calcium cations in the formulation was used as a molecular template to guide CaCO3 crystallization. Computational modeling of the FTIR spectra showed good agreement with experimental data and confirmed that calcium ions are bridged between polymer chains, resulting in a net-like polymer structure. The process readily lends itself to explore the feasibility of creating molecular sheets of other important inorganic materials and potentially find applications in many fields such as super capacitors and "low k di-electric" systems. PMID:27145699

  9. A Chemical Template for Synthesis of Molecular Sheets of Calcium Carbonate

    Science.gov (United States)

    Rianasari, Ina; Benyettou, Farah; Sharma, Sudhir Kumar; Blanton, Thomas; Kirmizialtin, Serdal; Jagannathan, Ramesh

    2016-05-01

    Inspired by the discovery of graphene and its unique properties, we focused our research to develop a scheme to create nacre like lamellar structures of molecular sheets of CaCO3 interleaved with an organic material, namely carbon. We developed a facile, chemical template technique, using a formulation of poly(acrylic) acid (PAA) and calcium acetate to create lamellar stacks of single crystal sheets of CaCO3, with a nominal thickness of 17 Å, the same as a unit-cell dimension for calcite (c–axis = 17.062 Å), interleaved with amorphous carbon with a nominal thickness of 8 Å. The strong binding affinity between carboxylate anions and calcium cations in the formulation was used as a molecular template to guide CaCO3 crystallization. Computational modeling of the FTIR spectra showed good agreement with experimental data and confirmed that calcium ions are bridged between polymer chains, resulting in a net-like polymer structure. The process readily lends itself to explore the feasibility of creating molecular sheets of other important inorganic materials and potentially find applications in many fields such as super capacitors and “low k di-electric” systems.

  10. A Chemical Template for Synthesis of Molecular Sheets of Calcium Carbonate

    Science.gov (United States)

    Rianasari, Ina; Benyettou, Farah; Sharma, Sudhir Kumar; Blanton, Thomas; Kirmizialtin, Serdal; Jagannathan, Ramesh

    2016-01-01

    Inspired by the discovery of graphene and its unique properties, we focused our research to develop a scheme to create nacre like lamellar structures of molecular sheets of CaCO3 interleaved with an organic material, namely carbon. We developed a facile, chemical template technique, using a formulation of poly(acrylic) acid (PAA) and calcium acetate to create lamellar stacks of single crystal sheets of CaCO3, with a nominal thickness of 17 Å, the same as a unit-cell dimension for calcite (c–axis = 17.062 Å), interleaved with amorphous carbon with a nominal thickness of 8 Å. The strong binding affinity between carboxylate anions and calcium cations in the formulation was used as a molecular template to guide CaCO3 crystallization. Computational modeling of the FTIR spectra showed good agreement with experimental data and confirmed that calcium ions are bridged between polymer chains, resulting in a net-like polymer structure. The process readily lends itself to explore the feasibility of creating molecular sheets of other important inorganic materials and potentially find applications in many fields such as super capacitors and “low k di-electric” systems. PMID:27145699

  11. Complexometric titration with potenciometric indicator to determination of calcium and magnesium in soil extracts¹

    OpenAIRE

    Claudia Mara Pereira; Cristhiane Anete Neiverth; Shizuo Maeda; Marcela Guiotoku; Luziane Franciscon

    2011-01-01

    This study proposes a method of direct and simultaneous determination of the amount of Ca2+ and Mg2+ present in soil extracts using a Calcium Ion-Selective Electrode and by Complexometric Titration (ISE-CT). The results were compared to those obtained by conventional analytical techniques of Complexometric Titration (CT) and Flame Atomic Absorption Spectrometry (FAAS). There were no significant differences in the determination of Ca2+ and Mg2+ in comparison with CT and FAAS, at a 95 % confide...

  12. Calcium and chemical looping technology for power generation and carbon dioxide (CO2) capture solid oxygen- and CO2-carriers

    CERN Document Server

    Fennell, Paul

    2015-01-01

    Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture reviews the fundamental principles, systems, oxygen carriers, and carbon dioxide carriers relevant to chemical looping and combustion. Chapters review the market development, economics, and deployment of these systems, also providing detailed information on the variety of materials and processes that will help to shape the future of CO2 capture ready power plants. Reviews the fundamental principles, systems, oxygen carriers, and carbon dioxide carriers relevant to calcium and chemical loopingProvi

  13. Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer

    Directory of Open Access Journals (Sweden)

    Milton Carlos KUGA

    2014-06-01

    Full Text Available Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. Objective: The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF or containing 5% (MTAF5 or 10% (MTAF10 calcium hydroxide (CH, in weight, in comparison with AH Plus sealer. Material and Methods: The flowability test was performed according to the ISO 6876:2001 requirements. For the pH level and calcium ion release analyses, the sealers were placed individually (n=10 in plastic tubes and immersed in deionized water. After 24 hours, 7 and 14 days, the water in which each specimen had been immersed was evaluated to determine the pH level changes and calcium released. Flowability, pH level and calcium release data were analyzed statistically by the ANOVA test (α=5%. Results: In relation to flowability: MTAF>AH Plus>MTAF5>MTAF10. In relation to the pH level, for 24 h: MTAF5=MTAF10=MTAF>AH Plus; for 7 and 14 days: MTAF5=MTAF10>MTAF>AH Plus. For the calcium release, for all periods: MTAF>MTAF5=MTAF10>AH Plus. Conclusions: The addition of 5% CH to the MTA Fillapex (in weight is an alternative to reduce the high flowability presented by the sealer, without interfering in its alkalization potential.

  14. Assessment of the extended Koopmans' theorem for the chemical reactivity: Accurate computations of chemical potentials, chemical hardnesses, and electrophilicity indices.

    Science.gov (United States)

    Yildiz, Dilan; Bozkaya, Uğur

    2016-01-30

    The extended Koopmans' theorem (EKT) provides a straightforward way to compute ionization potentials and electron affinities from any level of theory. Although it is widely applied to ionization potentials, the EKT approach has not been applied to evaluation of the chemical reactivity. We present the first benchmarking study to investigate the performance of the EKT methods for predictions of chemical potentials (μ) (hence electronegativities), chemical hardnesses (η), and electrophilicity indices (ω). We assess the performance of the EKT approaches for post-Hartree-Fock methods, such as Møller-Plesset perturbation theory, the coupled-electron pair theory, and their orbital-optimized counterparts for the evaluation of the chemical reactivity. Especially, results of the orbital-optimized coupled-electron pair theory method (with the aug-cc-pVQZ basis set) for predictions of the chemical reactivity are very promising; the corresponding mean absolute errors are 0.16, 0.28, and 0.09 eV for μ, η, and ω, respectively. PMID:26458329

  15. Precision age indicators that exploit chemically peculiar stars

    OpenAIRE

    Worthey, Guy

    2015-01-01

    We would like to find a way to improve the determination of galaxy star formation history from integrated light spectroscopy. To this end, several classes of chemically peculiar (CP) stars arise during the course of normal evolution in single stars and noninteracting binary stars. An aging stellar population has periods of time in which CP stars contribute to the integrated light, and others in which the contributions fade. The HgMn stars, for example, occupy a narrow temperature range of 105...

  16. Correlating Wine Quality Indicators to Chemical and Sensory Measurements

    Directory of Open Access Journals (Sweden)

    Helene Hopfer

    2015-05-01

    Full Text Available Twenty-seven commercial Californian Cabernet Sauvignon wines of different quality categories were analyzed with sensory and chemical methods. Correlations between five quality proxies—points awarded during a wine competition, wine expert scores, retail price, vintage, and wine region—were correlated to sensory attributes, volatile compounds, and elemental composition. Wine quality is a multi-faceted construct, incorporating many different layers. Depending on the quality proxy studied, significant correlations between quality and attributes, volatiles and elements were found, some of them previously reported in the literature.

  17. Physiological adaptive indicators in fasted neonate broiler chicks in response to calcium gluconate injection.

    Science.gov (United States)

    Khosravinia, H

    2016-06-01

    Four hundred and eighty mixed-sex broiler chicks aged 3 h after hatching were allotted according to a completely random design in a 6 × 2 × 2 factorial schedule into two groups of 12 replications of 20 chicks each. The main experimental factors were fasting for 0, 6, 12, 24, 36 and 48 h after chick placement and calcium gluconate (Ca-glu) injection (0 and 0.6 ml). Live body weight (BW) of chicks decreased linearly (Y = 43.36-0.109BW0 h , r(2)  = 0.876) as neonatal fasting extended. Injection of 0.6 ml Ca-glu at 3 h post-hatching did not affect weight loss of chicks. Yolk residuals (YR) utilized linearly (Y = 5.75-0.062YR, r(2)  = 0.956) by 0.062 g/h in neonate fasted chicks up to 48 h, showing no effect of Ca-glu injection. Neonatal fasting periods longer than 12 h increased liver weight (p < 0.05). The mean absolute and proportional (% of BW0 h ) breast and leg weight were reduced linearly as neonatal fasting extended (p < 0.05). Serum glucose concentration increased up to 6 h and then reduced linearly to 150 mg/dl after 48-h fasting. The Ca-glu treatment influenced serum glucose level for a short period up to 6 h of fasting. Serum Ca concentration sharply increased up to threefolds in the birds received Ca-glu injection resulting in acute hypercalcemia, then decreased to the initial level after 24-h feed withdrawal (p < 0.05). The mean serum level for creatinine, uric acid, cholesterol, HDL, albumins and total proteins significantly increased during the fasting periods of 6 to 48 h and significantly elevated in the birds receiving 0.6-ml Ca-glu injection compared with the non-treated chicks (p < 0.05). It was concluded that subcutaneous administration of 0.6 ml Ca-glu in the chick's neck did not suitably support the increased metabolic demands for glucose and calcium in feed-deprived neonate chicks. PMID:26344414

  18. A chemical activity evaluation of two dental calcium silicate-based materials

    Directory of Open Access Journals (Sweden)

    Chalas Renata

    2015-06-01

    Full Text Available Calcium silicate-based materials are interesting products widely used in dentistry. The study was designed to compare the chemical reaction between analyzed two preparates and dentin during cavity lining. In our work, dentinal discs were prepared from human extracted teeth filled with Biodentine and MTA+. The samples were then analyzed by way of SEM, EDS and Raman spectroscopy. The obtained results revealed differences in elemental composition between both materials. Biodentine showed higher activity in contact with dentine. Moreover, the interfacial layer in the tooth filled by Biodentine was wider than that in the tooth filled with MTA+. The applied methods of analysis confirmed that both materials have a bioactive potential which is a promising ability.

  19. CHEMICAL WATER QUALITY INDICATORS IN BASIN FOREST PARCZEW

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    Antoni Grzywna

    2014-10-01

    Full Text Available This paper presents the characteristics of the chemistry of surface and ground water in the bottom of the river valley reclaimed Ochoza. Drained grassland accounts for 20% of the total catchment area and are located on organic soils in the valley Tyśmienica classified to the Natura 2000 sites. Analysis of physico-chemical properties of water are to assess the effects of anthropogenic transformation and identify factors that influence water quality in the study area. Water samples were collected in the years 2011–2012 in several points. The walls were characterized by surface water stagnant in the trenches, in July, blueberry plantation. Characterized by the highest quality of surface water runoff river with the test object. Occurring here throughout the growing season water flow reed growing on the bed and temporary impoundment of water contribute to the self-cleaning effect of water. Conducted at different times of the growing season (winter, spring, summer, autumn of water chemistry analysis allows to assess the impact of vegetation on the process of self-purification of water. Based on the survey it was found that the river is reduced by 26% BOD 5, COD by 37%, 12% phosphate and potassium by 13%. Concurrently, an increase in the content of nitrogen compounds – ammonia at 27% and 15% nitrate. The increase in the content of nitrogen compounds is particularly evident in the bottom of the object, which is probably associated with the deep trench causing excessive drying of the soil. The highest values of pollutants were recorded mostly in the spring probably due to the outflow of water from the drans.

  20. Influence of precursor solution parameters on chemical properties of calcium phosphate coatings prepared using Electrostatic Spray Deposition (ESD).

    NARCIS (Netherlands)

    Leeuwenburgh, S.C.G.; Wolke, J.G.C.; Schoonman, J.; Jansen, J.A.

    2004-01-01

    A novel coating technique, referred to as Electrostatic Spray Deposition (ESD), was used to deposit calcium phosphate (CaP) coatings with a variety of chemical properties. The relationship between the composition of the precursor solutions and the crystal and molecular structure of the deposited coa

  1. 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.

  2. The Chemical Enrichment History of the Fornax Dwarf Spheroidal Galaxy from the Infrared Calcium Triplet

    CERN Document Server

    Pont, F; Gallart, C; Hardy, E; Winnick, R A; Pont, Frederic; Zinn, Robert; Gallart, Carme; Hardy, Eduardo; Winnick, Rebeccah

    2004-01-01

    Near infrared spectra were obtained for 117 red giants in the Fornax dwarf spheroidal galaxy with the FORS1 spectrograph on the VLT, in order to study the metallicity distribution of the stars and to lift the age-metallicity degeneracy of the red giant branch (RGB) in the color-magnitude diagram (CMD). Metallicities are derived from the equivalent widths of the infrared Calcium triplet lines at 8498, 8542, and 8662 A, calibrated with data from globular clusters, the open cluster M67 and the LMC. For a substantial portion of the sample, the strength of the Calcium triplet is unexpectedly high, clearly indicating that the main stellar population of Fornax is significantly more metal-rich than could be inferred from the position of its RGB in the CMD. We show that the relative narrowness of the RGB in Fornax is caused by the superposition of stars of very different ages and metallicities. The metallicity distribution in Fornax is centered at [Fe/H]= -0.9, with a metal-poor tail extending to [Fe/H] ~= -2. While t...

  3. Lung adenocarcinoma with Lambert–Eaton myasthenic syndrome indicated by voltage-gated calcium channel: a case report

    Directory of Open Access Journals (Sweden)

    Arai Hiromasa

    2012-09-01

    Full Text Available Abstract Introduction Lambert–Eaton myasthenic syndrome is a rare disorder and it is known as a paraneoplastic neurological syndrome. Small cell lung cancer often accompanies this syndrome. Lambert–Eaton myasthenic syndrome associated with lung adenocarcinoma is extremely rare; there are only a few reported cases worldwide. Case presentation A 75-year-old Japanese man with a past history of chronic rheumatoid arthritis and Sjögren syndrome was diagnosed with Lambert–Eaton myasthenic syndrome by electromyography and serum anti-P/Q-type voltage-gated calcium channel antibody level preceding the diagnosis of lung cancer. A chest computed tomography to screen for malignant lesions revealed an abnormal shadow in the lung. Although a histopathological examination by bronchoscopic study could not reveal the malignancy, lung cancer was mostly suspected after the results of a chest computed tomography and [18F]-fluorodeoxyglucose positron emission tomography. An intraoperative diagnosis based on the frozen section obtained by tumor biopsy was adenocarcinoma so the patient underwent a lobectomy of the right lower lobe and lymph node dissection with video-assisted thoracoscopic surgery. The permanent pathological examination was the same as the frozen diagnosis (pT2aN1M0: Stage IIa: TNM staging 7th edition. Immunohistochemistry revealed that most of the cancer cells were positive for P/Q-type voltage-gated calcium channel. Conclusions Our case is a rare combination of Lambert–Eaton myasthenic syndrome associated with lung adenocarcinoma, rheumatoid arthritis and Sjögren syndrome, and to the best of our knowledge it is the first report that indicates the presence of voltage-gated calcium channel in lung adenocarcinoma by immunostaining.

  4. Proteomic analysis of renal calculi indicates an important role for inflammatory processes in calcium stone formation

    OpenAIRE

    Merchant, Michael L.; Cummins, Timothy D.; Wilkey, Daniel W.; Salyer, Sarah A.; Powell, David W.; Klein, Jon B.; Eleanor D. Lederer

    2008-01-01

    Even though renal stones/calculi occur in ∼10% of individuals, they are an enormous economic burden to the entire US health system. While the relative metabolic composition of renal calculi is generally known, there is no clear understanding of the genetics of renal stone formation, nor are there clear prognostic indicators of renal stone formation. The application of proteomics to the analysis of renal calculi axiomatically holds that insight into renal stone pathobiology can be gained by a ...

  5. Chemical characteristics and hemostatic performances of ordered mesoporous calcium-doped silica xerogels

    Energy Technology Data Exchange (ETDEWEB)

    Wu Xiaohui; Wei Jie; Lu Xun; Lv Yang; Chen Fangping; Zhang Yanglan; Liu Changsheng, E-mail: csliu@sh163.ne [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)

    2010-06-01

    A well-ordered mesoporous silicon dioxide calcium-doped xerogel (m-SXC) was synthesized by a sol-gel process. The in vitro bioactivity of the m-SXC was investigated by analyzing the apatite-forming ability in simulated body fluid (SBF) and MC3T3-E1 cell culture with materials, and the hemostatic activity of the m-SXC was determined by measuring the activated partial thromboplastin time (APTT) and prothrombin time (PT) in vitro. The results suggested that the m-SXC exhibited excellent in vitro bioactivity, with surface apatite formation for the m-SXC containing 10 w% Ca (m-SXC10) exceeding that containing 5 w% Ca (n-SXC5) and 0% Ca (m-SXC0) at 7 days, and the cell response test (MTT assay) and cell morphology observation demonstrated that these materials were biocompatible with no obvious negative effects on cellular viability. Moreover, the m-SXC with a high surface area (m-SXC0: 489.9 m{sup 2} g{sup -1}, m-SXC5: 466.5 m{sup 2} g{sup -1}, m-SXC10: 438.1 m{sup 2} g{sup -1}) possessed good hemostatic property because it could absorb a large amount of water from the blood, which could concentrate the components of blood and reduce the clotting time. Furthermore, the addition of calcium in the m-SXC had significant effects on the clotting time, in which the APTT (m-SXC0: 8 s, m-SXC5: 7 s, m-SXC10: 6 s, respectively) and PT (m-SXC0: 16 s, m-SXC5: 11 s, m-SXC10: 10 s, respectively) were shortened with the increase of Ca amounts in the m-SXC, indicating that incorporation of Ca in the m-SXC could improve its hemostatic activity.

  6. Physico-chemical properties and toxic effect of fruit-ripening agent calcium carbide

    Directory of Open Access Journals (Sweden)

    Mohammad Asif

    2012-01-01

    Full Text Available Ripening is the final stage of the maturation process, when the fruit changes color, softens and develops the flavor, texture and aroma that constitute optimum eating quality. This study was conducted to discuss the use of unsatisfactory calcium carbide to ripen fruits for domestic markets as well as their toxic effects on human health. The commonly used ripening agents are calcium carbide, acetylene, ethylene, propylene, ethrel (2-chloroethyl phosphonic acid, glycol, ethanol and some other agents. The calcium carbide is one of the most commonly used ripening agent for fruits, while other calcium salts like calcium ammonium nitrate, calcium chloride and calcium sulfate are used to delay fruit ripening agents for local fruit industries. The use of calcium carbide is being discouraged worldwide, due to associated health hazards. Calcium carbide treatment of food is extremely hazardous because it contains traces of arsenic and phosphorous, and once dissolved in water, it produces acetylene gas. Arsenic, phosphorous and acetylene gas may affect the different body organs and causes various health problems like headache, dizziness, mood disturbances, sleepiness, mental confusion, memory loss, cerebral edema, seizures and prolonged hypoxia.

  7. Properties of Chemically Combusted Calcium Carbide Residue and Its Influence on Cement Properties

    Directory of Open Access Journals (Sweden)

    Hongfang Sun

    2015-02-01

    Full Text Available Calcium carbide residue (CCR is a waste by-product from acetylene gas production. The main component of CCR is Ca(OH2, which can react with siliceous materials through pozzolanic reactions, resulting in a product similar to those obtained from the cement hydration process. Thus, it is possible to use CCR as a substitute for Portland cement in concrete. In this research, we synthesized CCR and silica fume through a chemical combustion technique to produce a new reactive cementitious powder (RCP. The properties of paste and mortar in fresh and hardened states (setting time, shrinkage, and compressive strength with 5% cement replacement by RCP were evaluated. The hydration of RCP and OPC (Ordinary Portland Cement pastes was also examined through SEM (scanning electron microscope. Test results showed that in comparison to control OPC mix, the hydration products for the RCP mix took longer to formulate. The initial and final setting times were prolonged, while the drying shrinkage was significantly reduced. The compressive strength at the age of 45 days for RCP mortar mix was found to be higher than that of OPC mortar and OPC mortar with silica fume mix by 10% and 8%, respectively. Therefore, the synthesized RCP was proved to be a sustainable active cementitious powder for the strength enhanced of building materials, which will result in the diversion of significant quantities of this by-product from landfills.

  8. OPTIMIZATION OF CHEMICALS USE FOR HIGHLY FILLED MECHANICAL GRADE PAPERS WITH PRECIPITATED CALCIUM CARBONATE

    Directory of Open Access Journals (Sweden)

    Yizhou Sang

    2011-02-01

    Full Text Available Response surface methodology was used with four factors to screen for the best starch and optimize the use of chemicals in order to maximize precipitated calcium carbonate (PCC filler retention in a peroxide-bleached TMP suspension. Three commercial starches were used in conjunction with colloidal silica and flocculant. The PCC loading level and the interactions between PCC level, starch, flocculant, and silica were investigated, and empirical models were constructed. The empirical process models were then employed to predict the retention and drainage. It was found that medium-charged cationic starch (S858 gave the highest total and filler retention, whereas high-charged cationic starch (S880 resulted in the best drainage. The ash content of the handsheet can be pushed up to 40% using the retention system with medium (S858 and high (S880 charged cationic starch. The high-charged cationic starch (S880 gave stronger paper, probably because of its higher affinity with the fiber and fines.

  9. Genetic visualization with an improved GCaMP calcium indicator reveals spatiotemporal activation of the spinal motor neurons in zebrafish.

    Science.gov (United States)

    Muto, Akira; Ohkura, Masamichi; Kotani, Tomoya; Higashijima, Shin-ichi; Nakai, Junichi; Kawakami, Koichi

    2011-03-29

    Animal behaviors are generated by well-coordinated activation of neural circuits. In zebrafish, embryos start to show spontaneous muscle contractions at 17 to 19 h postfertilization. To visualize how motor circuits in the spinal cord are activated during this behavior, we developed GCaMP-HS (GCaMP-hyper sensitive), an improved version of the genetically encoded calcium indicator GCaMP, and created transgenic zebrafish carrying the GCaMP-HS gene downstream of the Gal4-recognition sequence, UAS (upstream activation sequence). Then we performed a gene-trap screen and identified the SAIGFF213A transgenic fish that expressed Gal4FF, a modified version of Gal4, in a subset of spinal neurons including the caudal primary (CaP) motor neurons. We conducted calcium imaging using the SAIGFF213A; UAS:GCaMP-HS double transgenic embryos during the spontaneous contractions. We demonstrated periodic and synchronized activation of a set of ipsilateral motor neurons located on the right and left trunk in accordance with actual muscle movements. The synchronized activation of contralateral motor neurons occurred alternately with a regular interval. Furthermore, a detailed analysis revealed rostral-to-caudal propagation of activation of the ipsilateral motor neuron, which is similar to but much slower than the rostrocaudal delay observed during swimming in later stages. Our study thus demonstrated coordinated activities of the motor neurons during the first behavior in a vertebrate. We propose the GCaMP technology combined with the Gal4FF-UAS system is a powerful tool to study functional neural circuits in zebrafish. PMID:21383146

  10. Calcium Oxalate Crystals as an Indicator of Plant Stress in Conifers at two elevations on Mount Moosilauke, NH

    Science.gov (United States)

    Allen, M. N.; Rock, B. N.; Hale, S. R.; Graham, K. J.

    2007-12-01

    The research presented was conducted as part of Watershed Watch, a two-week hands-on summer program for undeclared entry-level undergraduates, designed to recruit and retain students in Science, Technology, Engineering, and Mathematics (STEM) disciplines. The research was conducted on needles of red spruce (Picea rubens) and balsam fir (Abies balsamea) at the University of New Hampshire. The presence of calcium oxalate crystals (CaOx) in the cell walls of spruce mesophyll cells has been reported as an indicator of environmental stress. To assess this, first and third year needles of both species were collected from Mt. Moosilauke (Woodstock, NH) at two elevations (790m and 960m). Needles were analyzed using reflectance spectroscopy and scanning electron microscopy (SEM). Estimates of chlorophyll and water were made using the Red Edge Inflection Point and the Moisture Stress Index. These were compared to SEM images of needle sections to visually correlate the amount of CaOx with the reflectance indices. Balsam fir from 790m have a higher occurrence of CaOx in their first and third year needles than from the 960m site, while spectroscopy results indicated less stress (i.e., higher chlorophyll and more water) at the lower site. This does not support a correlation between CaOx and stress factors in balsam fir. In red spruce, those needles with fewest CaOx had higher estimates of chlorophyll and water, supporting the correlation. Based on these results, more research is needed to fully understand the relationship between CaOx and plant stress in different species of conifers.

  11. Chemical analysis and molecular models for calcium-oxygen-carbon interactions in black carbon found in fertile Amazonian anthrosoils.

    Science.gov (United States)

    Archanjo, Braulio S; Araujo, Joyce R; Silva, Alexander M; Capaz, Rodrigo B; Falcão, Newton P S; Jorio, Ado; Achete, Carlos A

    2014-07-01

    Carbon particles containing mineral matter promote soil fertility, helping it to overcome the rather unfavorable climate conditions of the humid tropics. Intriguing examples are the Amazonian Dark Earths, anthropogenic soils also known as "Terra Preta de Índio'' (TPI), in which chemical recalcitrance and stable carbon with millenary mean residence times have been observed. Recently, the presence of calcium and oxygen within TPI-carbon nanoparticles at the nano- and mesoscale ranges has been demonstrated. In this work, we combine density functional theory calculations, scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transformed infrared spectroscopy, and high resolution X-ray photoelectron spectroscopy of TPI-carbons to elucidate the chemical arrangements of calcium-oxygen-carbon groups at the molecular level in TPI. The molecular models are based on graphene oxide nanostructures in which calcium cations are strongly adsorbed at the oxide sites. The application of material science techniques to the field of soil science facilitates a new level of understanding, providing insights into the structure and functionality of recalcitrant carbon in soil and its implications for food production and climate change. PMID:24892495

  12. Effects of Zn Content on Crystal Structure, Cytocompatibility, Antibacterial Activity, and Chemical Stability in Zn-Modified Calcium Silicate Coatings

    Science.gov (United States)

    Li, Kai; Yu, Jiangming; Xie, Youtao; Huang, Liping; Ye, Xiaojian; Zheng, Xuebin

    2013-08-01

    In our previous study, Zn-modified calcium silicate coatings possess not only excellent chemical stability but also well antibacterial activity. Still, effects of zinc content on these properties and cytocompatibility remain unclear. In this paper, two kinds of Zn-modified calcium silicate coatings (ZC0.3, ZC0.5) were fabricated on Ti-6Al-4V substrates via plasma spraying technology. X-ray diffraction results and transmission electron microscopy observations showed that the ZC0.5 coating was composed of pure hardystonite (Ca2ZnSi2O7) phase, while, besides Ca2ZnSi2O7 phase, the amorphous CaSiO3 phase was also detected in the ZC0.3 coating. Chemical stability in Tris-HCl buffer solution and antibacterial activity of the Zn-modified calcium silicate coatings increased with an increase in zinc content. In vitro cytocompatibility evaluation demonstrated that the proliferation and alkaline phosphatase activity and collagen type I (COLI) secretion of osteoblast-like MC3T3-E1 cells on Zn-modified coatings were significantly enhanced compared to the Zn-free coating and Ti-6Al-4V control, and no cytotoxicity appeared on Zn-modified coatings. The better antibacterial activity and the enhanced capability to promote MC3T3-E1 cells differentiation of Zn-modified coatings should be attributed to the slow and constant Zn2+ releasing from the coatings.

  13. Optical recording of neuronal activity with a genetically-encoded calcium indicator in anesthetized and freely moving mice

    Directory of Open Access Journals (Sweden)

    Henry Lütcke

    2010-04-01

    Full Text Available Fluorescent calcium (Ca2+ indicator proteins (FCIPs are promising tools for functional imaging of cellular activity in living animals. However, they have still not reached their full potential for in vivo imaging of neuronal activity due to limitations in expression levels, dynamic range, and sensitivity for reporting action potentials. Here, we report that viral expression of the ratiometric Ca2+ sensor yellow cameleon 3.60 (YC3.60 in pyramidal neurons of mouse barrel cortex enables in vivo measurement of neuronal activity with high dynamic range and sensitivity across multiple spatial scales. By combining juxtacellular recordings and two-photon imaging in vitro and in vivo, we demonstrate that YC3.60 can resolve single action potential (AP-evoked Ca2+ transients and reliably reports bursts of APs with negligible saturation. Spontaneous and whisker-evoked Ca2+ transients were detected in individual apical dendrites and somata as well as in local neuronal populations. Moreover, bulk measurements using wide-field imaging or fiber-optics revealed sensory-evoked YC3.60 signals in large areas of the barrel field. Fiber-optic recordings in particular enabled measurements in awake, freely moving mice and revealed complex Ca2+ dynamics, possibly reflecting different behavior-related brain states. Viral expression of YC3.60 - in combination with various optical techniques - thus opens a multitude of opportunities for functional studies of the neural basis of animal behavior, from dendrites to the levels of local and large-scale neuronal populations.

  14. Stability-Indicating RP-HPLC Method Development and Validation for the Determination of Rosuvastatin (Calcium In Pharmaceutical Dosage Form

    Directory of Open Access Journals (Sweden)

    Zahi Mohammad Turabi

    2014-04-01

    Full Text Available A stability indicating, accurate, specific, linear and sensitive reverse phase-HPLC method has been developed and validated for the determination of Rosuvastatin as calcium, (ROS in pharmaceutical dosage form. The chromatographic separation was performed using end capped (Luna C18 Column (250 mm × 4.6 mm, 5μm particle size. Mobile phase A was prepared by mixing 3.0g/l Ammonium dihydrogen phosphate in distilled water: Methanol: Acetonitrile: Tetrahydrofuran in the ratios (400:20:100:5v/v. To 1000 ml of the resulting solution 1 ml of triethylamine was added then the pH was adjusted to 6.3 with 5% v/v orthophosphoric acid. Mobile phase B was prepared by mixing Acetonitrile: Methanol: Tetrahydrofuran in the ratios (500:50:5v/v. Other chromatographic conditions such as flow rate set at 2.0 ml/min and 30°C column temperature with the detection wavelength at 243nm. The retention times of Rosuvastatin was found to be about 16 min. The linearity was performed in the concentration range of 40.0-60.0μg/ml with a squared correlation coefficient of 0.99998. The percentage purity of ROS was found to be >99.8%. The percentage recovery was determined for ROS and was found to be 100.067%. The developed analytical method has been validated for specificity, linearity, precision, accuracy, ruggedness and robustness which were within the acceptance limit according to ICH guidelines. All the degradation products obtained by stress conditions were found to be well separated from the principal peak, which means that the ROS peaks were highly pure in all chromatograms obtained. The developed method was successfully employed for routine quality control and stability analysis of ROS in pharmaceutical dosage forms.

  15. Physical and chemical protection of soil organic carbon in three agricultural soils with different contents of calcium carbonate

    International Nuclear Information System (INIS)

    The amount of organic carbon physically protected by entrapment within aggregates and through polyvalent cation organic matter bridging was determined on non-calcareous and calcareous soils. The composition of organic carbon in whole soils and 13C NMR analysis. High energy photo-oxidation was carried out on <53 μm fractions and results from the NMR spectra showed 17-40% of organic carbon was in a condensed aromatic form, most likely charcoal (char). The concept that organic material remaining after photo-oxidation may be physically protected within aggregates was investigated by treating soils with a mild acid prior to photo-oxidation. More organic material was protected in the calcareous than the non-calcareous soils, regardless of whether the calcium occurred naturally or was an amendment. Acid treatment indicated that the presence of exchangeable calcium reduced losses of organic material upon photo-oxidation by about 7% due to calcium bridging. These results have implications for N fertiliser recommendations based upon organic carbon content. Firstly, calcium does not impact upon degradability of organic material to an extent likely to affect N fertiliser recommendations. Secondly, standard assessment techniques overestimate active organic carbon content in soils with high char content. Copyright (2000) CSIRO Publishing

  16. Determination of cytoplasmic calcium concentration in Dryopteris spores: a developmentally non-disruptive technique for loading of the calcium indicator fura-2

    Science.gov (United States)

    Scheuerlein, R.; Schmidt, K.; Poenie, M.; Roux, S. J.

    1991-01-01

    Germination of Dryopteris spores is mediated by the physiologically active, far-red-absorbing form of phytochrome, Pfr, and external Ca2+ is necessary for the transduction of the light signal. Because knowledge about the cytoplasmic calcium ion concentration, [Ca2+]i, is of great importance for understanding the role of calcium during signal transduction, this value was measured using fura-2 in fern spores undergoing the normal developmental progression into germination. Fura-2 was loaded into the spores by electroporation, which does not disrupt the normal process of germination. The intensity of the fluorescence emission of the loaded fura-2 was analysed by a microspectrophotometric assay of single spores, and successful loading could be obtained by the application of ten electrical pulses (field strength 7.5 kV cm-1, half-life (time constant) 230 microseconds). Fura-2 was alternately excited by light of wavelengths 355 and 385 nm through an inverted fluorescence microscope, and the emitted fura-2 fluorescence was collected by a silicon-intensified video camera. The cytoplasmic calcium ion concentration was calculated from the ratio of the camera output obtained for both wavelengths and displayed by a pseudo-color technique. Spores responded to changes of the extracellular Ca2+ concentration, and this observation is considered as evidence that fura-2 is loaded into the cytoplasm. The substitution of a low external [Ca2+] (1 mM ethyleneglycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA)) by 1 mM CaCl2 caused a fast increase of [Ca2+]i from approx. 50 nM to above 500 nM. In contrast, the subsequent substitution of CaCl2 by EGTA decreased [Ca2+]i again below 100 nM within 0.5 h. Furthermore, the application of ionomycin could initiate a change in [Ca2+]i according to the Ca2+ gradient established between the extracellular medium and cytoplasm. In spores sown on a Ca(2+) -free medium, [Ca2+]i, analysed in a buffer containing EGTA, was found to be around

  17. Chemical and structural characterization of glass ionomer cements indicated for atraumatic restorative treatment.

    Science.gov (United States)

    Guedes, Orlando Aguirre; Borges, Álvaro Henrique; Bandeca, Matheus Coelho; Nakatani, Mariana Kyosen; de Araújo Estrela, Cyntia Rodrigues; de Alencar, Ana Helena Gonçalves; Estrela, Carlos

    2015-01-01

    Glass ionomer cements (GICs) are restorative materials, which clinical use has increased significantly during the last decade. The aim of the present study was to analyze the chemical constitution and surface morphology of four glass ionomer cements: Maxxion R, VitroFill, Vidrion R and Vitremer. Twelve polyethylene tubes with an internal diameter of 3 and 3 mm in length were prepared, filled and then transferred to a chamber with 95% relative humidity and a temperature of 37°C. The surface morphology of the tested materials was examined by scanning electron microscopy (SEM) and main components were investigated by energy-dispersive X-ray microanalysis (EDX). Scanning electron microscopy revealed irregular and rough external surface. Cracking was not observed. The main constituents were found to be aluminum, silicon, calcium, sodium and fluoride. Phosphorus, sulfur and barium were only observed in Vidrion R, while chlorine were only observed in Maxxion R. Elemental mapping of the outer surface revealed high concentration of aluminum and silicon. Significant irregularities on the surface of the tested materials were observed. The chemical constitution of all GIC was similar. PMID:25876952

  18. Development of Chemical Indicators of Groundwater Contamination Near the Carcass Burial Site

    Science.gov (United States)

    Kim, H.; Choi, J.; Kim, M.; Choi, J.; Lee, M.; Lee, H.; Jeon, S.; Bang, S.; Noh, H.; Yoo, J.; Park, S.; Kim, H.; Kim, D.; Lee, Y.; Han, J.

    2011-12-01

    A serious outbreak of foot and mouth disease (FMD) and avian influenza (AI) led to the culling of millions of livestock in South Korea from late 2010 to earlier 2011. Because of the scale of FMD and AI epidemic in Korea and rapid spread of the diseases, mass burial for the disposal of carcass was conducted to halt the outbreak. The improper construction of the burial site or inappropriate management of the carcass burial facility can cause the contamination of groundwater mainly due to the discharges of leachate through the base of disposal pit. The leachate from carcass burial contains by products of carcass decay such as amino acids, nitrate, ammonia and chloride. The presence of these chemical components in groundwater can be used as indicators demonstrating contamination of groundwater with leachate from carcass. The major concern about using these chemical indicators is that other sources including manures, fertilizers and waste waters from human or animal activities already exist in farming area. However, we lack the understanding of how groundwater contamination due to mass burial of carcass can be differentiated from the contamination due to livestock manures which shows similar chemical characteristics. The chemical compositions of the leachate from carcass burial site and the wastewater from livestock manure treatment facilities were compared. The chemical compositions considered include total organic carbon (TOC), total nitrogen (TN), nitrate, organic nitrogen (Organic nitrogen =TN-Ammonium Nitrogen- Nitrate nitrogen), ammonia, chloride, sodium, potassium and amino acids (20 analytes). The ratios of concentrations of the chemical compositions as indicators of contamination were determined to distinguish the sources of contamination in groundwater. Indicators which showed a linear relationship between two factors and revealed a distinct difference between the carcass leachate and livestock manure were chosen. In addition, the background level of the

  19. Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter

    International Nuclear Information System (INIS)

    Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 μM of each tetracycline-derived compound 20 min prior to exposure to 500 μM iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs–Ringer–HEPES buffer at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca2+ uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca2+ uptake and suppressed the Ca2+-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca2+ uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. - Highlights: • Minocycline and doxycycline are the only cytoprotective tetracyclines of those tested • Cytoprotective tetracyclines inhibit the MPT and mitochondrial calcium and iron uptake. • Cytoprotective tetracyclines protect by

  20. Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L.; Smith, Charles D. [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Lemasters, John J., E-mail: JJLemasters@musc.edu [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC (United States)

    2013-11-15

    Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 μM of each tetracycline-derived compound 20 min prior to exposure to 500 μM iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs–Ringer–HEPES buffer at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca{sup 2+} uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca{sup 2+} uptake and suppressed the Ca{sup 2+}-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca{sup 2+} uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. - Highlights: • Minocycline and doxycycline are the only cytoprotective tetracyclines of those tested • Cytoprotective tetracyclines inhibit the MPT and mitochondrial calcium and iron uptake. • Cytoprotective

  1. Long-term effects of soil management practices on selected indicators of chemical soil quality

    Directory of Open Access Journals (Sweden)

    Alicja Pecio

    2016-06-01

    Full Text Available The study was conducted in scope of Catch-C project “Compatibility of agricultural management practices and types of farming in the EU to enhance climate change mitigation and soil health” (7FP, realized in 2012–2014 by the consortium of partners from 10 European countries (http://www.catch-c.eu. This work reports the effects of soil management practices – under different soil and climatic conditions – on the selected soil chemical quality indicators, based on the analysis of data extracted from literature on long term experiments (LTEs in Europe, as well as from LTEs held by the Catch-C consortium partners. The dataset related to soil chemical quality indicators consisted of 1044 records and referred to 59 long-term trials. The following indicators of chemical soil quality were analyzed: pH, N total content, N total stock, C:N ratio, N mineral content, P and K availability. They are the most frequently used indicators in the European literature on long-term experiments collected in the Catch-C project database. Soil organic carbon, however, the most important indicator was not presented here, due to it was covered by a separate study on indicators for climate change mitigation. The indicators were analyzed using their response ratio (RR to a management practice. For a given treatment (management practice, this ratio was calculated as the quotient between the indicator value obtained in the treatment, and the indicator value in the reference treatment. The examples were: rotation (with cereals, with legume crops, with tuber or root crops, with grassland vs. adequate monoculture, catch/cover crops vs. no catch/cover crops, no-tillage and no-inversion tillage vs. conventional tillage, mineral fertilization vs. no fertilization, organic fertilization (compost, farmyard manure, slurry vs. mineral fertilization at the same available nitrogen input, crop residue incorporation vs. removal. All tested practices influenced soil chemical quality

  2. Evaluating Chemical Tracers as Indicators of Nitrate-Nitrogen Sources in Groundwater

    Science.gov (United States)

    Nitka, A.; DeVita, W.; McGinley, P.

    2014-12-01

    Groundwater nitrate-N concentrations greater than 3 mg/L usually indicate contamination from either agriculture or wastewater disposal. The objective of this study was to use chemical indicators to reliably determine sources of nitrate contamination in private wells. We developed an analytical method for a suite of human waste indicators. The selection of chemical tracers was based on their likely occurrence and mobility in groundwater. The suite included artificial sweeteners, pharmaceuticals and personal care products. Pesticide metabolites were used to identify contamination due to agricultural practices. A densely populated suburban area with adjacent agricultural land was selected. Eighteen private water supply wells and six monitoring wells were analyzed for nitrate-N and contaminant indicators. All of the wells with nitrate concentrations greater than 3 mg/L had at least one chemical indicator. Of these, 90% had two or more human waste contaminants, 40% had pesticide metabolites, and 30% had both. Of the wells with nitrate greater than 10 mg/L, 80% had two or more human waste indicators, 70% had pesticide metabolites, and 50% had both. The results of this research will help direct land management decisions and selection of appropriate water treatment options.

  3. Physico-Chemical Study of the Separation of Calcium Isotopes by Chemical Exchange Between Amalgam and Salt Solutions

    International Nuclear Information System (INIS)

    In a preliminary study of the isotopic exchange between Ca amalgam and aqueous or organic solutions of Ca salts, the main parameters governing the feasibility of a separation process based on these systems such as separation factor, exchange kinetics, rate of decomposition of the amalgam were investigated. The separation factor between 40Ca and 46Ca was found to be of the order of 1.02. The rate of the exchange reaction is rather low for aqueous solutions, extremely low for organic solutions. The amalgam seems not to be attacked by dimethyl-formamide solutions; but it is rapidly decomposed by aqueous solutions of Ca halides. This decomposition is slow in the case of aqueous solutions of calcium formate and still slower for Ca(OH)2; however, except in particular conditions, the observed rate is often much higher, owing to interfering reactions between amalgam and water vapor contained in H2 bubbles. (authors)

  4. Verrucomicrobial community structure and abundance as indicators for changes in chemical factors linked to soil fertility.

    Science.gov (United States)

    Navarrete, Acacio Aparecido; Soares, Tielle; Rossetto, Raffaella; van Veen, Johannes Antonie; Tsai, Siu Mui; Kuramae, Eiko Eurya

    2015-09-01

    Here we show that verrucomicrobial community structure and abundance are extremely sensitive to changes in chemical factors linked to soil fertility. Terminal restriction fragment length polymorphism fingerprint and real-time quantitative PCR assay were used to analyze changes in verrucomicrobial communities associated with contrasting soil nutrient conditions in tropical regions. In case study Model I ("Slash-and-burn deforestation") the verrucomicrobial community structures revealed disparate patterns in nutrient-enriched soils after slash-and-burn deforestation and natural nutrient-poor soils under an adjacent primary forest in the Amazonia (R = 0.819, P = 0.002). The relative proportion of Verrucomicrobia declined in response to increased soil fertility after slash-and-burn deforestation, accounting on average, for 4 and 2 % of the total bacterial signal, in natural nutrient-poor forest soils and nutrient-enriched deforested soils, respectively. In case study Model II ("Management practices for sugarcane") disparate patterns were revealed in sugarcane rhizosphere sampled on optimal and deficient soil fertility for sugarcane (R = 0.786, P = 0.002). Verrucomicrobial community abundance in sugarcane rhizosphere was negatively correlated with soil fertility, accounting for 2 and 5 % of the total bacterial signal, under optimal and deficient soil fertility conditions for sugarcane, respectively. In nutrient-enriched soils, verrucomicrobial community structures were related to soil factors linked to soil fertility, such as total nitrogen, phosphorus, potassium and sum of bases, i.e., the sum of calcium, magnesium and potassium contents. We conclude that community structure and abundance represent important ecological aspects in soil verrucomicrobial communities for tracking the changes in chemical factors linked to soil fertility under tropical environmental conditions. PMID:26184407

  5. Chemical synthesis and characterization of magnesium substituted amorphous calcium phosphate (MG-ACP)

    International Nuclear Information System (INIS)

    Amorphous calcium phosphate (ACP) was synthesized by a simple aqueous precipitation using CaCl2 and Na3PO4 in the presence of MgCl2 to ensure the formation of the ACP phase at room temperature. Magnesium substituted ACP phases corresponding to two different compositions representing the two most prominent calcium phosphate phases (hydroxyapatite: Ca + Mg/P = 1.67 and tricalcium phosphate: Ca + Mg/P = 1.5) were synthesized by this simple approach. Both compositions of ACP phases resulted in their transformation into β-tricalcium phosphate upon heat treatment in air at 600 deg. C. X-ray diffraction (XRD), heat treatment, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and Brunauer-Emmett-Teller (BET) analyses were used to characterize the phase, thermal stability, surface area, and morphology of the synthesized ACP powders corresponding to the two different nominal Ca/P compositions. Although it is known that α-TCP is the phase that appears upon heat treatment at 600 deg. C unsubstituted ACP, substitution of magnesium ion in ACP (both TCP and HA composition) stabilized the structure of β-TCMP phase at 600 deg. C. Moreover, FT-IR analysis revealed that the ACP phase regardless of the composition, exhibited characteristic bands corresponding to that of HA, with the exception of the ACP corresponding to HA composition which exhibited a prominent OH vibrational mode.

  6. Preparation, Physical-Chemical Characterization, and Cytocompatibility of Polymeric Calcium Phosphate Cements

    Directory of Open Access Journals (Sweden)

    Rania M. Khashaba

    2011-01-01

    Full Text Available Aim. Physicochemical mechanical and in vitro biological properties of novel formulations of polymeric calcium phosphate cements (CPCs were investigated. Methods. Monocalcium phosphate, calcium oxide, and synthetic hydroxyapatite were combined with either modified polyacrylic acid, light activated polyalkenoic acid, or polymethyl vinyl ether maleic acid to obtain Types I, II, and III CPCs. Setting time, compressive and diametral strength of CPCs was compared with zinc polycarboxylate cement (control. Specimens were characterized using X-ray diffraction, scanning electron microscopy, and infrared spectroscopy. In vitro cytotoxicity of CPCs and control was assessed. Results. X-ray diffraction analysis showed hydroxyapatite, monetite, and brushite. Acid-base reaction was confirmed by the appearance of stretching peaks in IR spectra of set cements. SEM revealed rod-like crystals and platy crystals. Setting time of cements was 5–12 min. Type III showed significantly higher strength values compared to control. Type III yielded high biocompatibility. Conclusions. Type III CPCs show promise for dental applications.

  7. Chemical forms of calcium in CA,Zn- and Ca,Cd-containing grains excreted by tobacco trichomes

    Energy Technology Data Exchange (ETDEWEB)

    Sarret, G.; Isaure, M.-P. [Environmental Geochemistry Group, LGIT, Univ. of Grenoble and CNRS, Grenoble cedex 9 (France)], E-mail: geraldine.sarret@ujf-grenoble.fr; Marcus, M.A. [Advanced Light Source (ALS), Lawrence Berkeley National Lab, Berkeley, California (United States); Harada, E. [Environmental Geochemistry Group, LGIT, Univ. of Grenoble and CNRS, Grenoble cedex 9 (France); Div. of Forest Resources, College of Forest Sciences, Kangwon National Univ., Chunchon, Kangwon-do (Korea, Republic of); Choi, Y.-E. [Div. of Forest Resources, College of Forest Sciences, Kangwon National Univ., Kangwon-do (Korea, Republic of); Pairis, S. [Inst. Neel CNRS-UJF, Dept. Matiere Condensee, Materiaux et Fonctions, Pole Instrumentation (Microscopie Electronique), Grenoble cedex 9 (France); Fakra, S. [Advanced Light Source (ALS), Lawrence Berkeley National Lab, Berkeley, California (United States); Manceau, A. [Environmental Geochemistry Group, LGIT, Univ. of Grenoble and CNRS, Grenoble cedex 9 (France)

    2007-10-15

    Tobacco (Nicotiana tabacum L. cv. Xanthi) plants exposed to toxic levels of zinc and cadmium excrete metals through their leaf trichomes (epidermal hairs) as Zn,Ca- and Cd,Ca-containing grains. Little is known about the nature and formation mechanism of these precipitates. The chemical, crystalline, and noncrystalline compositions of individual grains produced by tobacco were studied by scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX), micro-X-ray diffraction ({mu}XRD), and calcium K-edge micro X-ray absorption near edge structure ({mu}XANES) spectroscopy. Zinc is predominantly incorporated in calcite and cadmium in calcite and vaterite. Aragonite, which occurs occasionally, does not seem to contain trace metals. In addition to being precipitated in its three possible polymorphic forms, calcite, aragonite, and vaterite, calcium is also speciated as amorphous CaCO{sub 3} and possibly organic Ca in some grains. Most often, a particular grain consists of two or more crystalline and noncrystalline phases. The observed variability of intra- and inter-grain elemental and phase composition suggests that this biomineralization process is not constrained by biological factors but instead results from thermodynamically and kinetically controlled reactions. This study illustrates the potential of laterally resolved X-ray synchrotron radiation techniques ({mu}XRD and {mu}XANES) to study biomineralization and metal immobilization processes in plants. (author)

  8. Chemical forms of calcium in CA,Zn- and Ca,Cd-containing grains excreted by tobacco trichomes

    International Nuclear Information System (INIS)

    Tobacco (Nicotiana tabacum L. cv. Xanthi) plants exposed to toxic levels of zinc and cadmium excrete metals through their leaf trichomes (epidermal hairs) as Zn,Ca- and Cd,Ca-containing grains. Little is known about the nature and formation mechanism of these precipitates. The chemical, crystalline, and noncrystalline compositions of individual grains produced by tobacco were studied by scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX), micro-X-ray diffraction (μXRD), and calcium K-edge micro X-ray absorption near edge structure (μXANES) spectroscopy. Zinc is predominantly incorporated in calcite and cadmium in calcite and vaterite. Aragonite, which occurs occasionally, does not seem to contain trace metals. In addition to being precipitated in its three possible polymorphic forms, calcite, aragonite, and vaterite, calcium is also speciated as amorphous CaCO3 and possibly organic Ca in some grains. Most often, a particular grain consists of two or more crystalline and noncrystalline phases. The observed variability of intra- and inter-grain elemental and phase composition suggests that this biomineralization process is not constrained by biological factors but instead results from thermodynamically and kinetically controlled reactions. This study illustrates the potential of laterally resolved X-ray synchrotron radiation techniques (μXRD and μXANES) to study biomineralization and metal immobilization processes in plants. (author)

  9. Associations of chemical tracers and faecal indicator bacteria in a tropical urban catchment.

    Science.gov (United States)

    Ekklesia, E; Shanahan, P; Chua, L H C; Eikaas, H S

    2015-05-15

    Surface water contamination by human faecal wastes is a widespread hazard for human health. Faecal indicator bacteria (FIB) are the most widely used indicators to assess surface water quality but are less-human-specific and have the potential to survive longer and/or occur naturally in tropical areas. In this study, 13 wastewater chemicals (chloride, boron, orthosphophate, detergents as methylene blue active substances, cholesterol, cholestanol, coprostanol, diethylhexyl phthalate, caffeine, acetaminophen, ibuprofen, sucralose and saccharin) were investigated in order to evaluate tracers for human faecal and sewage contamination in tropical urban catchments. Surface water samples were collected at an hourly interval from sampling locations with distinct major land uses: high-density residential, low-density residential, commercial and industrial. Measured concentrations were analysed to investigate the association among indicators and tracers for each land-use category. Better correlations were found between different indicators and tracers in each land-use dataset than in the dataset for all land uses, which shows that land use is an important determinant of drain water quality. Data were further segregated based on the hourly FIB concentrations. There were better correlations between FIB and chemical tracers when FIB concentrations were higher. Therefore, sampling programs must be designed carefully to take the time of sampling and land use into account in order to effectively assess human faecal and sewage contamination in urban catchments. FIB is recommended as the first tier in assessment of surface water quality impairment and chemical tracers as the second tier. Acetaminophen and coprostanol are recommended as chemical tracers for high-density residential areas, while chloride, coprostanol and caffeine are recommended for low-density residential areas. PMID:25770447

  10. Study of Chemical Constituents and Medicinal Uses of Indicator Species of District Bannu

    OpenAIRE

    Rehman ullah khan; Saad Ullah khan; Sultan Mehmood; Ihsan ullah; Aziz Khan

    2013-01-01

    The present study was carried out to assess record and report the chemical constituents and ethnobotanical knowledge of indicator species of District Bannu. Medicinal outlines of about 57 plants were recorded through interview local people i.e. farmers, herbalists, hakims and Medicinal plants user dealers. The present investigation comprises the indigenous uses of 57 species belonging to 36 families of Angiosperms based upon their utility. Out of this rich Medicinal germplasm, 66.15% plants a...

  11. Applying surrogates and indicators to assess removal efficiency of trace organic chemicals during chemical oxidation of wastewaters.

    Science.gov (United States)

    Dickenson, Eric R V; Drewes, Jörg E; Sedlak, David L; Wert, Eric C; Snyder, Shane A

    2009-08-15

    To respond to concerns associated with wastewater-derived contaminants water utilities are looking for new approaches for monitoring trace organic chemicals in conventional and advanced water treatment processes. This study examines the use of a combination of surrogate parameters and indicator compounds tailored to monitor the removal efficiency of advanced oxidation processes employed by treatment plants engaged in indirect potable water reuse programs. Potential surrogate parameters and indicator compounds, identified by reviewing previous publications and classified by their structural properties, were tested in pilot- and full-scale treatment systems. Dilantin, DEET, meprobamate, and iopromide are good indicators to assess optimized oxidation conditions while ozonating tertiary-treated wastewaters. UVA reduction, ozone byproduct formation, such as simple organic acids, and ozone exposure correlated with "sweet spot" compounds, where ozone exposure correlated with trace organic removal across five tertiary-treated wastewaters. Findings indicate that the proposed framework can serve as a conservative monitoring approach for advanced oxidation processes as well as other indirect potable reuse processes to ensure proper removal of identified and unidentified wastewater-derived organic contaminants, to detect failures in system performance, and is protective of public health. PMID:19746720

  12. Use of otolith strontium:calcium and zinc:calcium ratios as an indicator of the habitat of Percophis brasiliensis Quoy & Gaimard, 1825 in the southwestern Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Esteban Avigliano

    2015-03-01

    Full Text Available We evaluate the simultaneous use of Sr: Ca and Zn: Ca ratios of the sagitta otolith as a potential indicator of the habitat of Percophis brasiliensis along a latitudinal gradient in the southwestern Atlantic Ocean (34-42ºS and 51-67ºW, in order to reliably identify fish stocks. Fish were collected in three sampling sites: Argentine-Uruguayan Common Fishing Zone (AUCFZ, El Rincón (ER and San Matías Gulf (SMG. The otolith Sr:Ca and Zn:Ca ratios were determined by ICP-OES and EDTA volumetric method. The otolith Sr:Ca ratio was similar in the three sampling sites, while the Zn:Ca ratio was significantly higher in AUCFZ than in ER and SMG for all age groups. The discriminant analysis showed an association between the otolith Sr:Ca and Zn:Ca ratios from ER and SMG. Present results suggest the potential occurrence of two fish stocks of P. brasiliensis in the study area.

  13. Chemical alteration of cement materials in a radioactive waste repository environment. 3. Development of reactive transport computational code combined with incongruent dissolution model of calcium silicate hydrates

    International Nuclear Information System (INIS)

    For long-term performance assessment of a cementitious disposal system for TRU waste, a so-called reactive transport computational code, being a numerical simulation code coupled a geochemical model suited to the system includes cement hydrate and a solute transport model, so-called reactive transport computational code, has been developed. The thermodynamic model previously developed in our institute for incongruent dissolution of calcium silicate hydrate (C-S-H) gel, which is a principal product of hydrated cement phase, was incorporated into a geochemical code, Harphrq, to evaluate chemical equilibrium conditions containing cement hydrates. This modification of the code enables a user to evaluate adequately the chemical equilibrium of a system including cement hydrate, such as a dissolution/precipitation of C-S-H gel and/or a change of Ca/Si ratio in C-S-H gel. The modified geochemical code was coupled onto a simplified solute transport code using a compartment model. The coupled code could simulate the processes where various chemical species in aqueous phase migrate through the homogeneous porous materials while locally maintaining chemical equilibrium. The developed reactive transport computational code was verified by comparison with experimental results on batch-type dissolution tests and column-type alteration tests under flow-through conditions of ordinary Portland cement hydrate. Predictive calculation results by the developed code were reasonably accordant with the experimental results, e.g. the distribution of constituent minerals and the composition of pore water in altered ordinary Portland cement hydrate. The validity of the developed code was therefore verified. Analysis on the results by the calculation could indicates special features such as a distribution of Ca/Si ratio in C-S-H gel along the water-flow in the column, and a re-precipitation of C-S-H gel in the downstream side of the dissolution front of C-S-H gel. (author)

  14. Obtainment of calcium carbonate from mussels shell

    International Nuclear Information System (INIS)

    The mussels and oyster shell are discarded at environment, and this accumulation is causing negative consequences to ecosystem. Calcium carbonate is main constituent of the shell chemical composition. Aiming to reduce environmental aggression and generate income to shellfish producer, there was the possibility of using these shells as an alternative to commercial calcium carbonate. For this physics, chemicals and thermal properties were evaluated, using X-ray fluorescence, thermogravimetric analysis, size distribution, abrasiveness and scanning electronic microscopy. The results indicate that mussels shells have an initial degradation temperature higher than commercial calcium carbonate e same lost weight behavior and 95% of shell chemical composition is calcium carbonate. The sample size distribution was influenced by grinding condition and time as well as its abrasiveness. (author)

  15. Chemical and mechanical consequences of environmental barrier coating exposure to calcium-magnesium-aluminosilicate.

    Energy Technology Data Exchange (ETDEWEB)

    Harder, B.; Ramirez-Rico, J.; Almer, J. D.; Kang, L.; Faber, K. (X-Ray Science Division); (NASA Glenn Research Center); (Univ. of Seville); (Rolls-Royce Corp.); (Northwestern Univ.)

    2011-06-01

    The success of Si-based ceramics as high-temperature structural materials for gas turbine applications relies on the use of environmental barrier coatings (EBCs) with low silica activity, such as Ba{sub 1-x}Sr{sub x}Al{sub 2}Si{sub 2}O{sub 8} (BSAS), which protect the underlying components from oxidation and corrosion in combustion environments containing water vapor. One of the current challenges concerning EBC lifetime is the effect of sandy deposits of calcium-magnesium-aluminosilicate (CMAS) glass that melt during engine operation and react with the EBC, changing both its composition and stress state. In this work, we study the effect of CMAS exposure at 1300 C on the residual stress state and composition in BSAS-mullite-Si-SiC multilayers. Residual stresses were measured in BSAS multilayers exposed to CMAS for different times using high-energy X-ray diffraction. Their microstructure was studied using a combination of scanning electron microscopy and transmission electron microscopy techniques. Our results show that CMAS dissolves the BSAS topcoat preferentially through the grain boundaries, dislodging the grains and changing the residual stress state in the topcoat to a nonuniform and increasingly compressive stress state with increasing exposure time. The presence of CMAS accelerates the hexacelsian-to-celsian phase transformation kinetics in BSAS, which reacts with the glass by a solution-reprecipitation mechanism. Precipitates have crystallographic structures consistent with Ca-doped celsian and Ba-doped anorthite.

  16. A confocal study of mechanism of 5-hydroxytryptaminoinduced intracellular calcium dynamics in cultured ratstomach fundus smooth muscle cells with a new Ca2+indicator STDIn-AM

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Xiaoling; (张小玲); YAN; Hongtao; (阎宏涛)

    2002-01-01

    A new fluorescent Ca2+ indicator STDIn-AM for detecting i transients in cultured smooth muscle cells is presented. By making a comparison, the difference between STDIn and fluo-3 is discussed in detail. Using the new Ca2+ indicator, the mechanism of 5-hydroxytryptamino (5-HT) induced intracellular calcium dynamics in stomach fundus smooth muscle cells (SFSMC) of rats is investigated. It is shown that in contrast with fluo-3, STDIn is uniformly distributed in the cytosolic compartment but excluded from the nucleus, when it is transfected into cells. This feature makes it a real cytosol Ca2+ indicator and can reflect changes of cytosol more accurately than that of fluo-3. In addition, STDIn responds to the i transients more sensitive and faster than fluo-3. The results also show that, the L-type Ca2+ channel inhibitor Mn9202 and the PLC inhibitor Compound 48/80 can significantly inhibit the i elevation induced by 5-HT, while the PKC inhibitor D-Sphingosine can enhance the effect of 5-HT. The results suggest that 5-HT acts by the way of 5-HT2 receptors on SFSMC, then through 5-HT2 receptors coupled IP3/Ca2+ and GC/PKC double signal transduction pathways to make Ca2+ release from intracellular Ca2+ stores and Ca2+ influx possibly through L-type calcium channels.

  17. A note on ‘some physical and chemical indices of clique-inserted lattices’

    International Nuclear Information System (INIS)

    This paper is to point out that proposition 3.3 and some results from ‘Some physical and chemical indices of clique-inserted lattices’ (Zhang 2013 J. Stat. Mech. P10004) are incorrect, since the fact that a subdivision graph of r-regular G is a (r, 2)-semigraph and the graphs of proposition did not satisfy the condition of one of lemmas cited therein. Moreover, some counterexamples are presented; a short proof of the corresponding correct theorem is deduced via utilizing the characteristic polynomial of the Laplacian matrix, which corrects the proposition 3.3 and some related results in Zhang [2]. (paper)

  18. A further tool to monitor the coffee roasting process: aroma composition and chemical indices.

    Science.gov (United States)

    Ruosi, Manuela R; Cordero, Chiara; Cagliero, Cecilia; Rubiolo, Patrizia; Bicchi, Carlo; Sgorbini, Barbara; Liberto, Erica

    2012-11-14

    Coffee quality is strictly related to its flavor and aroma developed during the roasting process, that, in their turn, depend on variety and origin, harvest and postharvest practices, and the time, temperature, and degree of roasting. This study investigates the possibility of combining chemical (aroma components) and physical (color) parameters through chemometric approaches to monitor the roasting process, degree of roasting, and aroma formation by analyzing a suitable number of coffee samples from different varieties and blends. In particular, a correlation between the aroma composition of roasted coffee obtained by HS-SPME-GC-MS and degree of roasting, defined by the color, has been researched. The results showed that aroma components are linearly correlated to coffee color with a correlation factor of 0.9387. The study continued looking for chemical indices: 11 indices were found to be linearly correlated to the color resulting from the roasting process, the most effective of them being the 5-methylfurfural/2-acetylfuran ratio (index). PMID:23083340

  19. Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter.

    Science.gov (United States)

    Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L; Smith, Charles D; Lemasters, John J

    2013-11-15

    Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50μM of each tetracycline-derived compound 20 min prior to exposure to 500μM iodoacetic acid plus 1mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs-Ringer-HEPES buffer at pH6.2 for 4h prior to reoxygenation at pH7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca(2+) uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca(2+) uptake and suppressed the Ca(2+)-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca(2+) uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. PMID:24012766

  20. Short-term effects of different organic amendments on soil chemical, biochemical and biological indicators

    Science.gov (United States)

    Mondelli, Donato; Aly, Adel; Yirga Dagnachew, Ababu; Piscitelli, Lea; Dumontet, Stefano; Miano, Teodoro

    2014-05-01

    The limited availability of animal manure and the high cost of good quality compost lead to difficult soil quality management under organic agriculture. Therefore, it is important to find out alternative organic soil amendments and more flexible strategies that are able to sustain crop productivity and maintain and enhance soil quality. A three years study was carried out in the experimental fields of the Mediterranean Agronomic Institute of Bari located in Valenzano, Italy. The main objective of this research is to investigate the effects of different fertility management strategies on soil quality in order to estimate the role of innovative matrices for their use in organic farming. The experiment consists of seven treatments applied to a common crop rotation. The treatments include alternative organic amendments (1- olive mill wastewater OMW, 2- residues of mushroom cultivation MUS, 3- coffee chaff COF), common soil amendments (4- compost COM, 5- faba bean intercropping LEG, 6- cow manure - MAN) and as a reference treatment (7- mineral fertilizer COV). The soil quality was assessed before and after the application of the treatments, through biological (microbial biomass carbon and nitrogen, soil respiration and metabolic quotient), biochemical (soil enzymatic activities: β-glucosidase, alkaline phospatase, urease, fluorescein diacetate (FDA) hydrolysis), and chemical (pH, soil organic carbon, soil organic matter, total nitrogen, available phosphorous, exchangeable potassium, dissolved organic carbon and total dissolved nitrogen) indicators. Based on the results obtained after the second year, all treatments were able to improve various soil chemical parameters as compared to mineral fertilizer. The incorporation of COF and OMW seemed to be more effective in improving soil total N and exchangeable K, while MAN significantly increased available P. All the amendments enhance dissolved organic C, soil respiration, microbial biomass and metabolic quotient as

  1. Pollution evaluation in the Shahrood River: Do physico-chemical and macroinvertebrate-based indices indicate same responses to anthropogenic activities?

    Science.gov (United States)

    Sharifinia, Moslem; Mahmoudifard, Abbas; Imanpour Namin, Javid; Ramezanpour, Zohreh; Yap, Chee Kong

    2016-09-01

    This study evaluates the impact of anthropogenic activities on the Shahrood River using water physico-chemical variables and macroinvertebrates data sets obtained over a period of 12 months between February 2012 and February 2013 at 8 sampling sites. Biotic indices i.e. FBI and BMWP based on macroinvertebrates and physico-chemical indices (MPI, HPI and NSF-WQI) were employed to evaluate the water quality status in connection with natural- and human-induced pressures. Based on physico-chemical indices, water quality was categorized as low polluted level and it is suitable for drinking purposes. The water quality based on biotic indices was related to the anthropic activities; a clear deterioration of the water quality was observed from upstream to downstream sites. The water quality along the river changed from very good (class I; reference sites) to good (class II; midstream sites) and turned into moderate (class III) and poor (class IV) quality (downstream sites). These findings indicate that biotic indices are more powerful indicators in assessing water quality than physico-chemical indices. Allocapnia, Glossosoma and Hesperoperla were exclusively related to least disturbed sites, and Naididae, Orthocladiinae and Ecdyonurus were found in sites showing notable degradation. Our results recommended that the use of macroinvertebrates could be employed as a cost-effective tool for biomonitoring and controlling of polluted riverine ecosystems in the Middle East. Finally, the results from this study may be useful not only for developing countries, but also for any organization struggling to use macroinvertebrate based indices with restricted financial resources and knowledge. PMID:27343865

  2. Evaluating Chemical Tracers in Suburban Groundwater as Indicators of Nitrate-Nitrogen Sources

    Science.gov (United States)

    Nitka, A.; DeVita, W. M.; McGinley, P.

    2015-12-01

    The CDC reports that over 15 million US households use private wells. These wells are vulnerable to contamination. One of the most common contaminants in private wells is nitrate. Nitrate has a health standard of 10 mg/L. This standard is set to prevent methemaglobinemia, or "blue baby" syndrome, in infants. In extreme cases it can affect breathing and heart function, and even lead to death. Elevated nitrate concentrations have also been associated with increased risk of thyroid disease, diabetes, and certain types of cancer. Unlike municipal wells, there is no mandatory testing of private wells. It is the responsibility of users to have their well water tested. The objective of this research was to identify the most useful chemical tracers for determining sources of nitrate in private water supplies. Chemical characteristics, such as mobility in groundwater and water solubility, as well as frequency of use, were considered when choosing source indicators. Fourteen pharmaceuticals and personal care products unique to human use were chosen to identify wells impacted by septic waste. A bovine antibiotic and five pesticide metabolites were used to identify contamination from agricultural sources. Eighteen private wells were selected in a suburban area with septic systems and adjacent agricultural land. The wells were sampled five times and analyzed to provide a temporal profile of nitrate and the tracers. The artificial sweetener sucralose was found in >70% of private wells. Wells with sucralose detected had nitrate concentrations between 5-15 mg/L. The herbicide metabolite metolachlor ESA was detected in 50% of the wells. These wells typically had the highest nitrate concentrations, often >10 mg/L. The common use and frequent detection of these two compounds made them the most reliable indicators of nitrate sources evaluated in this study. This information will help well owners determine appropriate treatment and remediation options and could direct future

  3. Mercury in some chemical fertilizers and the effect of calcium superphosphate on mercury uptake by corn seedlings (Zea mays L.).

    Science.gov (United States)

    Zhao, Xiulan; Wang, Dingyong

    2010-01-01

    Mercury (Hg) contents in ten chemical fertilizers were determined, and the effect of calcium superphosphate (CSP) on the uptake and translocation of Hg in corn seedlings was investigated by pot experiments. CSP was applied at the levels of 0, 66.7, and 133.4 mg P2O5/kg to Hg-treated (2 mg/kg) and untreated soils. CSP had the highest Hg content (5.1 mg/kg), followed by the NPK compound fertilizer 15-5-5 (15% N, 5% P2O5, 5% K2O) (1.2 mg/kg), then by nitrogen fertilizers (except for ammonia sulfate) and potassium fertilizers. Application of CSP did not obviously influence the biomass of corn roots, but it significantly increased the biomass of corn shoots in Hg-treated soil. Application of CSP at the levels of 66.7 and 133.4 mg P2O5/kg did not obviously influence the uptake of Hg by corn seedlings on soils without Hg treatment, but it decreased the Hg uptake of corn seedlings significantly on Hg-treated soils. The transfer coefficient of Hg in corn seedlings improved slightly on soils without Hg treatment, but decreased slightly on Hg-treated soils with the application of CSP. These results implied that CSP could ameliorate Hg toxicity to corn seedlings by inhibiting the uptake and the translocation of Hg in plants on Hg-polluted soils. PMID:21179956

  4. Physico-Chemical and Structural Interpretation of Discrete Derivative Indices on N-Tuples Atoms

    Science.gov (United States)

    Martínez-Santiago, Oscar; Marrero-Ponce, Yovani; Barigye, Stephen J.; Le Thi Thu, Huong; Torres, F. Javier; Zambrano, Cesar H.; Muñiz Olite, Jorge L.; Cruz-Monteagudo, Maykel; Vivas-Reyes, Ricardo; Vázquez Infante, Liliana; Artiles Martínez, Luis M.

    2016-01-01

    This report examines the interpretation of the Graph Derivative Indices (GDIs) from three different perspectives (i.e., in structural, steric and electronic terms). It is found that the individual vertex frequencies may be expressed in terms of the geometrical and electronic reactivity of the atoms and bonds, respectively. On the other hand, it is demonstrated that the GDIs are sensitive to progressive structural modifications in terms of: size, ramifications, electronic richness, conjugation effects and molecular symmetry. Moreover, it is observed that the GDIs quantify the interaction capacity among molecules and codify information on the activation entropy. A structure property relationship study reveals that there exists a direct correspondence between the individual frequencies of atoms and Hückel’s Free Valence, as well as between the atomic GDIs and the chemical shift in NMR, which collectively validates the theory that these indices codify steric and electronic information of the atoms in a molecule. Taking in consideration the regularity and coherence found in experiments performed with the GDIs, it is possible to say that GDIs possess plausible interpretation in structural and physicochemical terms. PMID:27240357

  5. Combined use of meio- and macrobenthic indices to assess complex chemical impacts on a stream ecosystem

    Science.gov (United States)

    McKnight, Ursula S.; Sonne, Anne T.; Rasmussen, Jes J.; Traunspurger, Walter; Höss, Sebastian; Bjerg, Poul L.

    2016-04-01

    habitats for overall ecosystem health, many biological indices tend only to reflect the ecological quality of surface water, rather than of the sedimentary zones where the accumulation of pollutants is often highest. To address this issue, we monitored meiobenthic (i.e. nematodes) and macrobenthic invertebrate communities along a pollution gradient in order to assess the impact of multiple stressors on a groundwater-fed stream, and thus quantify the link between chemical and ecological status. The studied stressors included point source pollutants originating from contaminated groundwater and aquaculture, and diffuse source pollutants originating from conventional agriculture and urban areas. The use of macrofauna is now well-accepted for assessing ecological integrity in aquatic ecosystems, but less is known about the application of meiofaunal community indicators. High abundance and ubiquitous distribution are two potential advantages for including meiofaunal indicators, and notably - for the case of groundwater-surface water interactions - they are particularly suitable for identifying changes in environmental conditions over smaller spatial scales. The results indicate a change in community composition for both meio- and macrobenthic fauna, pointing towards the presence of a local impact resulting from the discharging contaminated groundwater, which extends downstream along a dilution gradient of the groundwater contaminants. Ecological impacts could be linked to xenobiotic compounds coming from groundwater (both chlorinated solvents and pharmaceuticals), as well as the presence of trace metals of diffuse and/or biogenic origin.

  6. The Short-Term Effect of Chest Physiotherapy on Spirometric Indices in Chemical Warfare Victims Exposed to Mustard Gas

    OpenAIRE

    Abedi, A.; HR Koohestani; Z Roosta

    2008-01-01

    ABCTRACT Introduction & Objective: Chronic respiratory diseases are the most prevalent late sequels of sulfur mustard gas injury among Iranian chemical warfare victims. Chest physiotherapy is one of the useful methods in care, cure and infection prevention of these patients. The aim of this study was to determine the short-term effect of chest physiotherapy on spirometric indices in chemical warfare victims exposed to sulfur mustard gas. Materials & Methods: In this study, 27 of the chemical ...

  7. Sterilization of health care products - Chemical indicators - Part 3: Class 2 indicator systems for use in the Bowie and Dick-type steam penetration test. 2. ed.

    International Nuclear Information System (INIS)

    This part of ISO 11140 specifies the requirements for chemical indicators to be used in the steam penetration test for steam sterilizers for wrapped goods, e.g. instruments and porous materials. The indicator for this purpose is a Class 2 indicator as described in ISO 11140-1. Indicators complying with this part of ISO 11140 are intended for use in combination with the standard test pack as described in EN 285. This part of ISO 11140 does not consider the performance of the standard test pack, but does specify the performance of the indicator systems.The paper provides information on scope, normative references, terms and definitions, general requirements, indicator system format, performance requirements, packaging and labelling and quality assurance. 11 annexes report on the determination of strength after steam sterilization, the estimation of visual difference between colour of the substrate and the changed (or unchanged) indicator system by determination of relative reflectance density, the determination of indicator colour change on exposure to dry saturated steam, the determination of indicator colour change on exposure to dry heat, the accelerated ageing of test samples, the determination of transfer of indicator to standard test pack on processing, the determination of shelf life of the product, the steam exposure apparatus, the determination of sensitivity of the indicator to the presence of air, the air injection system and the standard test pack. Finally a bibliography is provided.

  8. Soft chemical synthesis and electrochemical properties of calcium ferrite-type LixMn2O4

    Science.gov (United States)

    Mamiya, Mikito; Tokiwa, Kazuyasu; Akimoto, Junji

    2016-04-01

    Calcium ferrite (CaFe2O4)-type LixMn2O4 was prepared via high-pressure and soft chemical synthesis method. The framework structure of CaFe2O4-type NaMn2O4 was synthesized from the stoichiometric mixture of Na2CO3 and MnO2 annealed by 1273 K for 1 h under 4.5 GPa. Na/Li ion-exchange of the CaFe2O4-type NaMn2O4 was carried out by soaking molten LiNO3 at 633 K for 12 h. The electrochemical properties of the ion-exchanged CaFe2O4-type LixMn2O4 were measured. The initial discharge profile in the voltage range from 4.0 to 1.0 V showed 458 mAh g-1 of the discharge capacity with two plateaus near 3.7 V and 2.7 V (vs. Li/Li+). The discharge capacity was decreased with increasing the cycle number. After 30 cycles, the capacity was decreased to 375 mAh g-1. When the range was set between 4.8 and 3.0 V, the discharge capacity was 113 mAh g-1 in initial, and 111 mAh g-1 after 50th cycle. The reference CaFe2O4-type LiMn2O4 was prepared via one-step high-pressure synthesis and compared the electrochemical properties with the ion-exchanged sample. The initial discharge capacity of the one-step synthesized one was 108 mAh g-1 at 1.0 V (vs. Li/Li+), which was 73% lower than the value of the ion-exchanged one.

  9. Calcium oxide/carbon dioxide reactivity in a packed bed reactor of a chemical heat pump for high-temperature gas reactors

    International Nuclear Information System (INIS)

    The thermal performance of a chemical heat pump that uses a calcium oxide/carbon dioxide reaction system was discussed as a heat storage system for utilizing heat output from high temperature gas reactors (HTGR). Calcium oxide/carbon dioxide reactivity for the heat pump was measured using a packed bed reactor containing 1.0 kg of reactant. The reactor was capable of storing heat at 900 deg. C by decarbonation of calcium carbonate and generating up to 997 deg. C by carbonation of calcium oxide. The amount of stored heat in the reactor was 800-900 kJ kg-1. The output temperature of the reactor could be controlled by regulating the carbonation pressure. The thermal storage performance of the reactor was superior to that of conventional sensible heat storage systems. A heat pump using this CaO/CO2 reactor is expected to contribute to thermal load leveling and to realize highly efficient utilization of HTGR output due to the high heat storage density and high-quality temperature output of the heat pump

  10. Effects of Exterior Abscisic Acid on Calcium Distribution of Mesophyll Cells and Calcium Concentration of Guard Cells in Maize Seedlings

    Institute of Scientific and Technical Information of China (English)

    GUO Xiu-lin; MA Yuan-yuan; LIU Zi-hui; LIU Bin-hui

    2008-01-01

    In this study, the direct effects of exterior abscisic acid (ABA) on both calcium distribution of mesophyll cells and cytosolic calcium concentration of guard cells were examined. The distribution of Ca2+ localization were observed with calcium antimonate precipitate-electromicroscopic-cyto-chemical methods after treated with ABA and pretreated with ethylene glycol-bis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), verapamil (Vp), and trifluoperazine (TFP). The laser scanning confocal microscopy was used to measure the cytosolic calcium concentrations of guard cells under different treatments. The results showed that the cytosolic Ca2+ concentration of mesophyll cells was induced to increase by ABA, but to decrease in both outside cell and the vacuoles within 10 min after treatments. The cytosolic calcium concentration of guard cells was increased gradually with the lag in treatment time. However, both EGTA and TFP could inverse those effects, indicating that the increase of cytosolic calcium induced by exterior ABA was mainly caused by calcium influx. The results also showed that calmodulin could influence both the calcium distribution of mesophyll cells and calcium concentration of guard cells. It shows that calmodulin participates in the process of ABA signal transduction, but the mechanism is not known as yet. The changes both calcium distribution of mesophyll cells and calcium concentration of guard cells further proved that the variations of cytosolic Ca2+ concentration induced by ABA were involved in the stomatal movements of maize seedlings.

  11. Study of Chemical Constituents and Medicinal Uses of Indicator Species of District Bannu

    Directory of Open Access Journals (Sweden)

    Rehman ullah khan

    2013-06-01

    Full Text Available The present study was carried out to assess record and report the chemical constituents and ethnobotanical knowledge of indicator species of District Bannu. Medicinal outlines of about 57 plants were recorded through interview local people i.e. farmers, herbalists, hakims and Medicinal plants user dealers. The present investigation comprises the indigenous uses of 57 species belonging to 36 families of Angiosperms based upon their utility. Out of this rich Medicinal germplasm, 66.15% plants are wild while 44.18%, species were found to be cultivated, 26.74% species are both wild and cultivated of the total flora of this area. The most important medicinal families are Solanaceae (7 spp, 12.28%, Asteraceae (5 spp, 8.77%, Mimosaceae (3 spp, 5.26%, Moraceae (3 spp, 5.26%, Malvaceae, Amaranthaceae, Chenopodiaceae, Euphorbiaceae, Papilionaceae, Plantaginaceae, and Rhamnaceae (2 spp, 3.51% While the remaining 25 families having 1 species each which is 1.75% of all families. The most common medicinal plants in the area are Abroma augusta (L. F., Acacia modesta wall., Achyranthes bidentata Blume , Albizia lebbeek L., Calotropis procera L., Capparis decidua Forsk Carthamus oxycantha M. B, Chenopodium album L., Citrus medica L., Citrullus colocynthis Schrad, Cuscuta reflexa Roxb, Cynodon dactylon L. Cyperus rotundrus L., Dodonia viscosa L., Eucalyptus globule L., Nerium oleander L., Papaver somniferum L., Trachy spermum ammi L. Typha orientallis J. Preslw., Vitex negundo L., Withania somnifera L., Xanthium strumarium L., Zizphus mauratiana Lam., Some plants have wild fruits i.e.., Solanum nigrum L., while Nerium oleander L. and Dodonaea viscosa (L. Jaeq are ornamental.

  12. 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.

  13. [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

  14. Physical–chemical and biological behavior of an amorphous calcium phosphate thin film produced by RF-magnetron sputtering

    International Nuclear Information System (INIS)

    This work evaluates the thermal reactivity and the biological reactivity of an amorphous calcium phosphate thin film produced by radio frequency (RF) magnetron sputtering onto titanium substrates. The analyses showed that the sputtering conditions used in this work led to the deposition of an amorphous calcium phosphate. The thermal treatment of this amorphous coating in the presence of H2O and CO2 promoted the formation of a carbonated HA crystalline coating with the entrance of CO32− ions into the hydroxyl HA lattice. When immersed in culture medium, the amorphous and carbonated coatings exhibited a remarkable instability. The presence of proteins increased the dissolution process, which was confirmed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Moreover, the carbonated HA coating induced precipitation independently of the presence of proteins under dynamic conditions. Despite this surface instability, this reactive calcium phosphate significantly improved the cellular behavior. The cell proliferation was higher on the Ticp than on the calcium phosphate coatings, but the two coatings increased cellular spreading and stress fiber formation. In this sense, the presence of reactive calcium phosphate coatings can stimulate cellular behavior. - Highlights: ► Functionalization of Ti with reactive CaP thin film by RF-magnetron sputtering. ► De-hydroxylation facilitating the insertion of CO32− into the HA lattice. ► High surface reactivity in the presence of culture medium. ► Cell behavior improved by the presence of reactive films.

  15. 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.

  16. Dynamic behavior of chemical reactivity indices in density functional theory: A Bohn-Oppenheimer quantum molecular dynamics study

    Indian Academy of Sciences (India)

    Shubin Liu

    2005-09-01

    Dynamic behaviors of chemical concepts in density functional theory such as frontier orbitals (HOMO/LUMO), chemical potential, hardness, and electrophilicity index have been investigated in this work in the context of Bohn-Oppenheimer quantum molecular dynamics in association with molecular conformation changes. Exemplary molecular systems like CH$^{+}_{5}$ , Cl- (H2O)30 and Ca2+ (H2O)15 are studied at 300 K in the gas phase, demonstrating that HOMO is more dynamic than LUMO, chemical potential and hardness often fluctuate concurrently. It is argued that DFT concepts and indices may serve as a good framework to understand molecular conformation changes as well as other dynamic phenomena.

  17. Methods of use of calcium hexa aluminate refractory linings and/or chemical barriers in high alkali or alkaline environments

    Science.gov (United States)

    McGowan, Kenneth A; Cullen, Robert M; Keiser, James R; Hemrick, James G; Meisner, Roberta A

    2013-10-22

    A method for improving the insulating character/and or penetration resistance of a liner in contact with at least one of an alkali and/or alkaline environments is provided. The method comprises lining a surface that is subject to wear by an alkali environment and/or an alkaline environment with a refractory composition comprising a refractory aggregate consisting essentially of a calcium hexa aluminate clinker having the formula CA.sub.6, wherein C is equal to calcium oxide, wherein A is equal to aluminum oxide, and wherein the hexa aluminate clinker has from zero to less than about fifty weight percent C.sub.12A.sub.7, and wherein greater than 98 weight percent of the calcium hexa aluminate clinker having a particle size ranging from -20 microns to +3 millimeters, for forming a liner of the surface. This method improves the insulating character/and or penetration resistance of the liner.

  18. Chemical Applications of Graph Theory: Part I. Fundamentals and Topological Indices.

    Science.gov (United States)

    Hansen, Peter J.; Jurs, Peter C.

    1988-01-01

    Explores graph theory and use of topological indices to predict boiling points. Lists three indices: Wiener Number, Randic Branching Index and Molecular Connectivity, and Molecular Identification numbers. Warns of inadequacies with stereochemistry. (ML)

  19. 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....

  20. Chemical indicators of cryoturbation and microbial processing throughout an alaskan permafrost soil depth profile

    Science.gov (United States)

    Although permafrost soils contain vast stores of carbon, we know relatively little about the chemical composition of their constituent organic matter. Soil organic matter chemistry is an important predictor of decomposition rates, especially in the initial stages of decomposition. Permafrost, organi...

  1. Chemical signals in the stingless bee, Frieseomelitta varia, indicate caste, gender, age, and reproductive status.

    Science.gov (United States)

    Nunes, Túlio M; Turatti, Izabel C C; Lopes, Norberto P; Zucchi, Ronaldo

    2009-10-01

    Chemical compounds on the cuticle are a rich source of information used during interactions among social insects. Despite the multitude of studies on these substances and their function in ants, wasps, and honeybees, little is known about this subject in stingless bees (Hymenoptera: Apidae, Meliponini). We studied the chemical composition of the cuticle of the stingless bee, Frieseomelitta varia, by gas chromatography-mass spectrometry (GC-MS), to investigate potential chemical variation among castes, gender, age, and reproductive status. We found differences in the cuticular hydrocarbon composition among workers, males, and queens, recording both qualitative and quantitative differences among individuals of different ages and gender. The cuticle of physogastric queens presented a chemical profile that was distinct from all other groups in the analysis, with high relative abundances of alkenes and alkadienes with 27, 29, and 31 carbon atoms. We discuss the possibility that these compounds signal a queen's presence to the colony, thereby initiating all vital worker-queen interactions. PMID:19813058

  2. 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 ...

  3. 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 ...

  4. 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

  5. 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...

  6. Reduced calcium-dependent mitochondrial damage underlies the reduced vulnerability of excitotoxicity-tolerant hippocampal neurons.

    Science.gov (United States)

    Pivovarova, Natalia B; Stanika, Ruslan I; Watts, Charlotte A; Brantner, Christine A; Smith, Carolyn L; Andrews, S Brian

    2008-03-01

    In central neurons, over-stimulation of NMDA receptors leads to excessive mitochondrial calcium accumulation and damage, which is a critical step in excitotoxic death. This raises the possibility that low susceptibility to calcium overload-induced mitochondrial damage might characterize excitotoxicity-resistant neurons. In this study, we have exploited two complementary models of preconditioning-induced excitotoxicity resistance to demonstrate reduced calcium-dependent mitochondrial damage in NMDA-tolerant hippocampal neurons. We have further identified adaptations in mitochondrial calcium handling that account for enhanced mitochondrial integrity. In both models, enhanced tolerance was associated with improved preservation of mitochondrial membrane potential and structure. In the first model, which exhibited modest neuroprotection, mitochondria-dependent calcium deregulation was delayed, even though cytosolic and mitochondrial calcium loads were quantitatively unchanged, indicating that enhanced mitochondrial calcium capacity accounts for reduced injury. In contrast, the second model, which exhibited strong neuroprotection, displayed further delayed calcium deregulation and reduced mitochondrial damage because downregulation of NMDA receptor surface expression depressed calcium loading. Reducing calcium entry also modified the chemical composition of the calcium-buffering precipitates that form in calcium-loaded mitochondria. It thus appears that reduced mitochondrial calcium loading is a major factor underlying the robust neuroprotection seen in highly tolerant cells. PMID:18036152

  7. Influence of Calcium Hydroxide Chemical, Multi-enzyme and Lactobacillus Biologic Processing on Nutritional Value and Digestibility of Rice Straw by Using Nylon-Bags

    Directory of Open Access Journals (Sweden)

    S. Salehpor

    2012-07-01

    Full Text Available This research has been conducted to survey the influence of chemical (Calcium Hydroxide, enzyme (Multi-enzyme and bacterial (lactobacillus processing on nutritional value and digestibility of rice straw by using nylon-bags and chemical methods. Processing performed for 60 days in anaerobic condition in 3-kg tanks by spraying method in 3 replications. The experiment conducted in complete block design and obtained data were analyzed through SAS and Neway software. After processing period, samples were dried and chemical compounds Crude Protein (CP, Neutral Detergent Fiber (NDF, Acid Detergent Fiber (ADF, Ether Extract (EE, Ash, Crude Fiber (CF, NFC (Non Fiber Carbohydrate, Nitrogen Free Extract (NFE and Organic Material (OM and in situ (at times 0, 4, 8, 16, 24, 48, 72 and 96 h techniques were conducted using 3 fistulated sheep weighted similar to incubation. All three processing methods decreased cellulose and hemicellulose materials in straw and straw in bacterial processing has the least ADF (51.2% and it has the most amount of ADF in enzyme processing (53.8%, chemical processing (57.9% and control group (58.2%. The same results obtained about NDF in straw so that straw has the least amount NDF in bacterial processing and it has the most amounts respectively in enzyme, chemical and control group processing. Amount of degradability and disappearance of dry matter in in situ technique was more in chemical processing than other processing and it is on an uptrend over passing time of incubation.

  8. A Combined Heuristic and Indicator-based Methodology for Design of Sustainable Chemical Process Plants

    DEFF Research Database (Denmark)

    Halim, Iskandar; Carvalho, Ana; Srinivasan, Rajagopalan;

    2011-01-01

    The current emphasis on sustainable production has prompted chemical plants to minimize raw material and energy usage without compromising on economics. While computer tools are available to assistin sustainability assessment, their applications are constrained to a specific domain of the design ......, comprehensive generation of design alternatives, and effective reduction of the optimization search space. The frame-work is illustrated using anacetone process and a methanol and dimethyl ether production case study....

  9. Chemical and Microbiological Examening of Final Meat Products as an Indicator of their Quality

    OpenAIRE

    Kuzelov, Aco

    2010-01-01

    The study shows the results from a chemical and microbiological examining of certain meat products produced from different types of pork meat (tenderloin - pork chop, ham, and collar) by a meat processing company from Republic of Macedonia. We have examined 10 pieces of tenderloin - pork chops, 10 pieces of pork ham and 10 pieces of pork collar. The pork tenderloin contained in average 71.72% of water, 28.88% of proteins, 5.98% of fat and 1.00% of minerals. The pork ham contain...

  10. Chemical Alteration on Mars Indicated by the Iron-Manganese Ratio

    Science.gov (United States)

    Yen, A. S.; Clark, B. C.; Ming, D. W.; Mittlefehldt, D. W.; Gellert, R.; Morris, R. V.

    2010-01-01

    The Alpha Particle X-ray Spectrometers (APXS) onboard the Mars Exploration Rovers (MER) have measured the chemical compositions of over 400 samples on the surface of Mars. Fe and Mn are among the elements which are well established by this instrumentation. Fe2+ and Mn2+ have nearly the same ionic radii and distribute similarly in primary igneous rocks, maintaining a consistent Fe:Mn ratio. Upon exposure to an oxidative weathering environment, Fe 3+ and Mn4+ are commonly formed, and elemental fractionation can occur. Thus, altered samples will typically exhibit a Fe:Mn ratio different from precursor materials.

  11. Estimation and characterization of physical and inorganic chemical indicators of water quality by using SAR images

    Science.gov (United States)

    Shareef, Muntadher A.; Toumi, Abdelmalek; Khenchaf, Ali

    2015-10-01

    Recently, remote sensing is considering one of the most important tools in studies of water scattering and water characterization. Traditional methods for monitoring pollutants depended on optical satellite rather than Radar data. Thus, many of Water Quality Parameters (WQP) from optical imagery are still limited. In this paper, a new approach based on the TerraSAR-X images has been presented which it is used to map the region of interest and to estimate physical and chemical WQPs. This approach based on a Small Perturbation Model (SPM) for the electromagnetic scattering is applied by using the Elfouhaily spectrum. A series of inversions have been included in this model started by finding the reflectivity from backscattering coefficients which are calculated from SAR images. Another inversion has been applied to find dielectric constant from the calculation models of the reflectivity (in HH and VV polarizations). Then, a Stogryn Debye formulation has been used to estimate temperature and salinity of water surface from SAR images. After many derivations we got a new model able to estimate temperature and salinity directly from backscattering coefficients obtained from radar images. Inorganic chemical parameters which are represented by Total Dissolved Salts (TDS) and the Electrical Conductivity (EC) are estimated directly from salinity. A tow dataset of instu data have been used to validate this work. The validation included a comparison between parameters measured in situ and those estimated from Terra SAR-X image.

  12. Physico-Chemical Study of the Separation of Calcium Isotopes by Chemical Exchange Between Amalgam and Salt Solutions; Etude physico-chimique de la separation des isotopes du calcium par echange chimique entre amalgame et solution saline

    Energy Technology Data Exchange (ETDEWEB)

    Duie, P.; Dirian, G. [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1962-07-01

    In a preliminary study of the isotopic exchange between Ca amalgam and aqueous or organic solutions of Ca salts, the main parameters governing the feasibility of a separation process based on these systems such as separation factor, exchange kinetics, rate of decomposition of the amalgam were investigated. The separation factor between {sup 40}Ca and {sup 46}Ca was found to be of the order of 1.02. The rate of the exchange reaction is rather low for aqueous solutions, extremely low for organic solutions. The amalgam seems not to be attacked by dimethyl-formamide solutions; but it is rapidly decomposed by aqueous solutions of Ca halides. This decomposition is slow in the case of aqueous solutions of calcium formate and still slower for Ca(OH){sub 2}; however, except in particular conditions, the observed rate is often much higher, owing to interfering reactions between amalgam and water vapor contained in H{sub 2} bubbles. (authors) [French] On a fait une etude preliminaire, pour des systemes amalgame de calcium - solution aqueuse ou organique de sels de calcium, des principaux parametres pouvant intervenir dans l'application d'un procede d'echange a l'enrichissement isotopique du calcium: facteur de separation, cinetique de l'echange, cinetique de la decomposition de l'amalgame. Les facteurs de separation {sup 40}Ca-{sup 46}Ca sont de l'ordre de 1,02. L'echange est assez lent pour les solutions aqueuses, extremement lent pour les solutions organiques. La decomposition de l'amalgame est pratiquement inexistante avec les solutions dans le dimethyl- formamide, appreciable pour les solutions alcooliques, rapide pour les solutions aqueuses d'halogenures; elle est normalement lente pour les solutions aqueuses de formiate et surtout de chaux, mais la decomposition est en general acceleree par une reaction parasite entre l'amalgame et l'eau a l'etat vapeur, reaction que l'on n'evite dans des

  13. Atributos químicos de solos influenciados pela substituição do carbonato por silicato de cálcio Soil chemical properties influenced by the substitution of calcium carbonate by calcium silicate

    Directory of Open Access Journals (Sweden)

    Renato Ferreira de Souza

    2008-08-01

    ácia do silicato de Ca foi inferior à de carbonato de Ca na melhoria das condições químicas do solo.The application of silicates to soils can result in increased soil cation exchange capacity (CEC, displace anions, especially H2PO4- (diacid phosphate, neutralize the pH and Al toxicity and, in general, increase the nutrient availability to plants. However, calcium silicates may be less efficient than calcium carbonates. To evaluate the effect of calcium carbonate substitution by calcium silicate on the soil chemical properties, especially on phosphorus availability, four experiments were conducted in an entirely randomized design with four replications, in a greenhouse. The treatments consisted of five levels (0, 25, 50, 75, and 100 % of calcium carbonate substitution by calcium silicate, with a 4:1 Ca:Mg stoichiometric and the same amount of CaO, enough to reach a 60 % base saturation. The treatments were applied to 4 dm³ samples of a sandy orthic Quartzarenic Neosol (Quartzpsament, a sandy loam dystrophic Red-Yellow Latosol (Oxisol, sandy clay loam dystrophic Red-Yellow Latosol (Oxisol and a clayey dystrophic Red Latosol (Oxisol; each soil represented one experiment. The pH values in H2O, P, phosphorus in the equilibrium solution (P-rem, K, Ca, Mg, Si, Al, H + Al, organic matter (OM, Cu, Mn, Zn and B, sum of bases (S, effective (t ant total (T CEC, base saturation (V and Al saturation (m were submitted to analysis of variance and simple regression models fitted as a function of CaCO3 substitution by CaSiO3 levels. It was observed that carbonate substitution by silicate promoted significant increases in the values of Si, Al, H + Al and m and reduction in the values of P-rem, pH, S, t and V. The values of Mehlich 1 P, K, Mg, OM, T, Mn, Cu, and B were not influenced significantly. A reduction in Zn availability was verified in the dystrophic orthic Quartzarenic Neosol only. Calcium silicate was less efficient than calcium carbonate in the improvement of soil chemical

  14. 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

  15. Talc indices from Boumnyebel (Central Cameroon), physico-chemical characteristics and geochemistry

    Science.gov (United States)

    Nkoumbou, C.; Njopwouo, D.; Villiéras, F.; Njoya, A.; Yonta Ngouné, C.; Ngo Ndjock, L.; Tchoua, F. M.; Yvon, J.

    2006-05-01

    Two talc schist occurrences were discovered in the Boumnyebel area, embedded in the Pan-African mica schist, at the junction between Archean, Eburnean and Neoproterozoic formations in Cameroon. They have been analysed by different techniques such as chemical analyses, XRD, DRIFTS, DTA and TG. The talc schist of the northern deposit contains talc (up to 95 wt%) with chlorite, goethite and lepidocrocite as minor minerals. The talc schist of the southern deposit has up to 88% of talc and is speckled with dark green phenoblasts of amphiboles (coexisting prismatic tremolite and magnesio-riebeckite). Due to its high talc content, the amphibole-free talc schist is economically attractive. Chemical analyses show that most of the rocks consist of SiO 2, MgO and Fe 2O 3, except the sample from the southern deposit that displays some amounts of Al 2O 3 and CaO. Among trace elements, Ni, Co and Cr are as high as in serpentinized peridotites, and suggest a protolith of ultrabasic nature. Chromium concentration in tremolite reaches 6178 ppm; most of the trace elements (Cd, Cr, Dy, Er, Eu, Ga, Gd, Ho, Lu, Nd, Pr, Sm, Sn, Sr, Tb, Tm, Y, Yb, Zr) are compatible with a tremolite lattice. The regional metamorphism yielded garnet micaschist nappes and thus belongs to the upper greenschist facies. Based on the high talc contents of the rocks and occasional coexisting tremolite and magnesio-riebeckite, the origin of the talc deposits is assigned to a hydrothermal alteration of ultramafic rocks. During the hydrothermal event, the fluid composition changed from silica-rich to lime-rich, but very few trace element contents were affected. Thus the low Rb, Sr, Th, Nb, K, Ta, Y, Zr, Hf, MREE and HREE and high Ni, Cr, Co contents of the rocks point to depleted peridotites (harzburgite-lherzolite) and pyroxenite as protoliths. The hydrothermal alteration is expressed in the positive cerium anomaly accompanied by little LREE enrichment of talc-rich rocks and hornblendite. The studied talc schist

  16. Density functional theory of chemical reactivity indices in some ion-molecule reaction systems

    International Nuclear Information System (INIS)

    Three isoelectronic reactions, proton transfer (PT), hydrogen abstraction (HA), and electron transfer (ET), of NH3+ with NH3, H2O, and HF have been studied using ab initio molecular orbital calculations. For the reaction of NH3+ + H2O, the energy of the transition state (TS) is higher than that of the reactants. This is consistent with the experimental observation that the rate constant is less than the average dipole orientation (ADO) rate constant. It seems reasonable that the reaction rate for the reaction NH3+ + H2O would hardly depend on the V2 mode of NH3+ at least for low-lying excited states (Eint≤ 0.714 eV) of the V2 mode, because the V2 contributes mainly to the normal mode orthogonal to the reaction coordinate at the TS. This is consistent with experimental observation. A similiar prediction can be made for the NH3+ + HF reaction. The electron transfer processes for the HA reactions have been examined in terms of the intrinsic reaction coordinate (IRC). The order of reactivity with NH3+ is NH3>H2O>HF. It is found that the degree of the electron transfer and the reactivity are correlated with the absolute hardness η of NH3, H2O, and HF. this is accord with the softness as the chemical reactivity index in the density functional theory. 25 refs., 6 fig., 4 tab

  17. THE "CHEMICAL OXYGEN DEMAND / TOTAL VOLATILE ACIDS" RATIO AS AN ANAEROBIC TREATABILITY INDICATOR FOR LANDFILL LEACHATES

    Directory of Open Access Journals (Sweden)

    R. C. Contrera

    2015-03-01

    Full Text Available Abstract In some operational circumstances a fast evaluation of landfill leachate anaerobic treatability is necessary, and neither Biochemical Methane Potential nor BOD/COD ratio are fast enough. Looking for a fast indicator, this work evaluated the anaerobic treatability of landfill leachate from São Carlos-SP (Brazil in a pilot scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR. The experiment was conducted at ambient temperature in the landfill area. After the acclimation, at a second stage of operation, the AnSBBR presented efficiency above 70%, in terms of COD removal, utilizing landfill leachate without water dilution, with an inlet COD of about 11,000 mg.L-1, a TVA/COD ratio of approximately 0.6 and reaction time equal to 7 days. To evaluate the landfill leachate biodegradability variation over time, temporal profiles of concentration were performed in the AnSBBR. The landfill leachate anaerobic biodegradability was verified to have a direct and strong relationship to the TVA/COD ratio. For a TVA/CODTotal ratio lower than 0.20, the biodegradability was considered low, for ratios between 0.20 and 0.40 it was considered medium, and above 0.40 it was considered high.

  18. NiTi shape memory alloys coated with calcium phosphate by plasma-spraying. Chemical and biological properties

    Energy Technology Data Exchange (ETDEWEB)

    Prymak, O.; Epple, M. [Institute of Inorganic Chemistry, University of Duisburg-Essen, D-45117 Essen (Germany); Bogdansk, D.; Esenwein, S.A.; Koeller, M. [Department of Surgery, BG Kliniken Bergmannsheil - Universitaetsklinik, Buerkle-de-la-Camp-Platz 1, D-44780 Bochum (Germany)

    2004-05-01

    Plates of superelastic nickel-titanium shape memory alloy (NiTi) were coated with calcium phosphate (hydroxyapatite) by high-temperature plasma-spraying. The porous layer of about 100 {mu}m thickness showed a good adhesion to the metallic substrate that withstood bending of the plate but detached upon cutting the plate. The biocompatibility was tested by cultivation of blood cells (whole blood and isolated granulocytes [a subpopulation of blood leukocytes]). As substrates, pure NiTi, plasma-spray-coated NiTi and calcium phosphate-coated NiTi prepared by a dip-coating process were used. The adhesion of whole blood cells to all materials was not significantly different. In contrast, isolated granulocytes showed an increased adhesion to both calcium phosphate-coated NiTi samples. However, compared to non-coated NiTi or dip-coated NiTi, the number of dead granulocytes adherent to plasma-sprayed surfaces was significantly increased for isolated granulocytes (p<0.01). (Abstract Copyright [2004], Wiley Periodicals, Inc.) [German] Bleche aus superelastischer Nickel-Titan-Legierung (NiTi) wurden durch Hochtemperatur-Plasmaspritzen mit Calciumphosphat (Hydroxylapatit) beschichtet. Die Haftung der ca. 100 {mu}m starken poroesen Schicht auf der metallischen Unterlage ist so gut, dass das Blech gebogen werden kann. Das Schneiden des Bleches fuehrte allerdings zur Abloesung der Schicht. Die Biokompatibilitaet der beschichteten Bleche wurde im Zellkulturexperiment mit Blutzellen (Vollblut und isolierte Granulozyten, [eine Subpopulation von Blutleukozyten]) untersucht. Zum Vergleich wurden reines NiTi und Calciumphosphat-beschichtetes NiTi (hergestellt durch einen Tauchprozess) ebenfalls in der Zellkultur untersucht. Die Adhaerenz der Vollblutzellen an die Materialien war nicht signifikant unterschiedlich. Im Gegensatz dazu zeigten isolierte Granulozyten eine hoehere Adhaesion auf beiden Calciumphosphat-beschichteten NiTi-Proben. Die Anzahl von toten Granulozyten war auf

  19. Assessing the potential hazard of chemical substances for the terrestrial environment. Development of hazard classification criteria and quantitative environmental indicators.

    Science.gov (United States)

    Tarazona, J V; Fresno, A; Aycard, S; Ramos, C; Vega, M M; Carbonell, G

    2000-03-20

    Hazard assessment constitutes an essential tool in order to evaluate the potential effects of chemical substances on organisms and ecosystems. It includes as a first step, hazard identification, which must detect the potential dangers of the substance (i.e. the kind of effects that the substance may produce), and a second step to quantify each danger and to set the expected dose/response relationships. Hazard assessment plays a key role in the regulation of chemical substances, including pollution control and sustainable development. However, the aquatic environment has largely received more attention than terrestrial ecosystems. This paper presents the extrapolation of several basic concepts from the aquatic to the terrestrial compartment, and suggests possibilities for their regulatory use. Two specific proposals are discussed. The first focuses on the scientific basis of the hazard identification-classification criteria included in the EU regulations and their extrapolation to the terrestrial environment. The second focuses on the OECD programme for environmental indicators and the development of a soil pollution pressure indicator to quantify the potential hazards for the soil compartment and its associated terrestrial ecosystem related to the toxic chemicals applied deliberately (i.e. pesticides) or not (i.e. heavy metals in sludge-based fertilisers; industrial spills) to the soil. PMID:10803544

  20. Chemical composition of water hyacinth (Eichhronia Crassipes) a comparison indication of heavy metal pollution in egyptian water bodies. Vol. 4

    International Nuclear Information System (INIS)

    Water hyacinth is tested as an indicator for pollution in egyptian fresh surface waters. Chemical composition of water hyacinth as affected area of collection (water bodies) was studied and the suitability of this plant as a biological indicator for water pollution is discussed. Water hyacinth samples were collected three times per year for two years (1991-1993). Sample sites include one location in the river nile (at Helwan area), one site in Ismaillia canal, (at Mostrod industrial area), and one site in Abo-Zabal drain (at Abo-Zabal city). The concentration of 19 major major and trace elements in plant samples were determined by prompt gamma-ray neutron activation analysis. Results indicated that plant parts as well as location have a significant effect on elements content. Water hyacinth roots showed high affinity for accumulation of trace elements. 5 tabs

  1. Preliminary studies of quality assessment of aquatic environments from Cluj suburban areas, based on some invertebrates bioindicators and chemical indicators

    Directory of Open Access Journals (Sweden)

    Gheorghe Stan

    2010-02-01

    Full Text Available Systematic categories of invertebrates bioindicators correlated with some chemical parameters,were an effective way to characterize the quality of lotic (Someş River and lentic (Lake Gilău aquatic environment from Cluj-Napoca area. Invertebrate fauna was represented by species belonging to the following dominant systematic categories: Nematoda, Annelida, Crustacea and Insecta. This paper containsalso some preliminary data on the bioindicators species belonging to Protozoa phylum. Dominant groups were crustaceans (the sampling points in Lake Gilău and annelids (Somes River and among species Gammarus pulex, Daphnia pulex, Tubifex tubifex. The fauna composition shows the β-α mesosaprobic character of the water, with an evolution from β mesosaprobity upstream the Cluj-Napoca city to polysaprobic downstream of the city. This aspect has been observed and analyzed according to chemical parameters (pH, TDS, ORP, EC, t and indices of saprobity (relative cleanliness, state of relative pollution, the deficit of species, saprobiological index.Systematic categories of invertebrates bioindicators correlated with some chemical parameters, were an effective way to characterize the quality of lotic (Someş River and lentic (Lake Gilău aquatic environment from Cluj-Napoca area. Invertebrate fauna was represented by species belonging to the following dominant systematic categories: Nematoda, Annelida, Crustacea and Insecta. This paper contains also some preliminary data on the bioindicators species belonging to Protozoa phylum. Dominant groups were crustaceans (the sampling points in Lake Gilău and annelids (Somes River and among species Gammarus pulex, Daphnia pulex, Tubifex tubifex. The fauna composition shows the β-α mesosaprobic character of the water, with an evolution from β mesosaprobity upstream the Cluj-Napoca city to polysaprobic downstream of the city. This aspect has been observed and analyzed according to chemical parameters (pH, TDS, ORP

  2. Chemical logging of geothermal wells

    Science.gov (United States)

    Allen, C.A.; McAtee, R.E.

    The presence of geothermal aquifers can be detected while drilling in geothermal formations by maintaining a chemical log of the ratio of the concentrations of calcium to carbonate and bicarbonate ions in the return drilling fluid. A continuous increase in the ratio of the concentrations of calcium to carbonate and bicarbonate ions is indicative of the existence of a warm or hot geothermal aquifer at some increased depth.

  3. Evaluation of specific ultraviolet absorbance as an indicator of the chemical composition and reactivity of dissolved organic carbon

    Science.gov (United States)

    Weishaar, J.L.; Aiken, G.R.; Bergamaschi, B.A.; Fram, M.S.; Fujii, R.; Mopper, K.

    2003-01-01

    Specific UV absorbance (SUVA) is defined as the UV absorbance of a water sample at a given wavelength normalized for dissolved organic carbon (DOC) concentration. Our data indicate that SUVA, determined at 254 nm, is strongly correlated with percent aromaticity as determined by 13C NMR for 13 organic matter isolates obtained from a variety of aquatic environments. SUVA, therefore, is shown to be a useful parameter for estimating the dissolved aromatic carbon content in aquatic systems. Experiments involving the reactivity of DOC with chlorine and tetramethylammonium hydroxide (TMAH), however, show a wide range of reactivity for samples with similar SUVA values. These results indicate that, while SUVA measurements are good predictors of general chemical characteristics of DOC, they do not provide information about reactivity of DOC derived from different types of source materials. Sample pH, nitrate, and iron were found to influence SUVA measurements.

  4. Phase formation and chemical phase equilibria in aqueous-based systems pertinent to waste-management: calcium oxide-alluminum oxide-borate-water, calcium oxide-lead oxide-phosphate-water and calcium oxide-arsenate-water

    Science.gov (United States)

    Bothe, James Vincent, Jr.

    This thesis explores three aqueous-based systems that have importance in the area of waste-management: (1) CaO-Alsb2Osb3-Bsb2Osb3-Hsb2O, (2) CaO-PbO-Psb2Osb5-Hsb2O and (3) CaO-Assb2Osb5-Hsb2O. More specifically, the objective of this research is to identify various precipitated compounds that can effectively immobilize certain elements that either directly or indirectly have an adverse effect on the environment. In the first quaternary system, CaO-Alsb2Osb3-Bsb2Osb3-Hsb2O, boron is the element desired to be ``fixed'' because ``free'' boron is the cause of delayed hardening in cement paste intended for the encapsulation of nuclear waste. Soluble boron also causes the cement paste to prematurely set, a phenomenon called ``flash-set.'' Isothermal calorimetry was used to track the progress of tricalcium aluminate hydration in the presence of boric acid and Ca(OH)sb2 and revealed the presence of a pronounced induction period, the length of which varied with both temperature and boric acid concentration. It was determined that a diffusion barrier, most likely an amorphous calcium borate, deposited onto the active anhydrous tricalcium aluminate grains inhibiting further hydration. Also, under certain conditions, the precipitation of crystalline 4CaO{*}Alsb2Osb3{*}1/2Bsb2Osb3{*}12Hsb2O may be responsible for the observed flash-set due to its flat, plate-like morphology. Another quaternary hydrate, 6CaO{*}Alsb2Osb3{*}2Bsb2Osb3{*}39Hsb2O (boro-ettringite) was also synthesized during this research and crystallized as hexagonal prisms. In contrast to the fast crystallization of 4CaO{*}Alsb2Osb3{*}1/2Bsb2Osb3{*}12Hsb2O, boro-ettringite was observed to form slowly and in stages with the precipitation of the transient phase CaO-Bsb2Osb3{*}6Hsb2O preceding it. Further investigation of these two hydrates lead to the construction of a quaternary phase diagram and to the determination of their solubility products (pKsp = -logKsp), which were determined to be 44.23 for boro

  5. Calcium phosphate thin films synthesized by pulsed laser deposition: Physico-chemical characterization and in vitro cell response

    Science.gov (United States)

    Mihailescu, I. N.; Torricelli, P.; Bigi, A.; Mayer, I.; Iliescu, M.; Werckmann, J.; Socol, G.; Miroiu, F.; Cuisinier, F.; Elkaim, R.; Hildebrand, G.

    2005-07-01

    We review the progress made by us using pulsed laser deposition (PLD) of two bioactive calcium phosphates: octacalcium phosphate (OCP) and Mn doped carbonated hydroxyapatite (Mn-CHA). Coatings of these materials well suited for biomimetic medical prostheses and pivots were synthesized on titanium substrates with a pulsed KrF* UV laser source. The best deposition conditions for Mn-CHA thin films were 13 Pa O 2, 400 °C with post heat treatment of 6 h in air enriched with water vapours. The coatings are stoichiometric and crystalline. For OCP, deposition at 150 °C in 50 Pa water vapor atmosphere, post treated by 6 h annealing in hot flux of water vapours, resulted in stoichiometric, but poorly-crystallized films. Degradation tests show different behavior for the OCP and Mn-CHA coatings. In vitro cell growth shows excellent adherence and biocompatibility of osteoblasts and fibroblasts in both OCP and Mn-CHA coatings. Human osteoblasts display normal proliferation and viability, and good differentiation behaviour.

  6. Calcium phosphate thin films synthesized by pulsed laser deposition: Physico-chemical characterization and in vitro cell response

    Energy Technology Data Exchange (ETDEWEB)

    Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, 77125 Bucharest-Magurele (Romania)]. E-mail: mihailes@ifin.nipne.ro; Torricelli, P. [Servizio di Chirurgia Sperimentale-Istituto di Ricerca Codivilla PuttiIOR, Bologna (Italy); Bigi, A. [Department of Chemistry ' G. Ciamician' , University of Bologna, 40126 Bologna (Italy); Mayer, I. [Department of Inorganic and Analytical Chemistry, Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Iliescu, M. [Institute of Physics and Chemistry of Materials, 67037 Strasbourg (France); Werckmann, J. [Institute of Physics and Chemistry of Materials, 67037 Strasbourg (France); Socol, G. [National Institute for Lasers, Plasma and Radiation Physics, 77125 Bucharest-Magurele (Romania); Miroiu, F. [National Institute for Lasers, Plasma and Radiation Physics, 77125 Bucharest-Magurele (Romania); Cuisinier, F. [Institut National de la Sante et de la Recherche Medicale, 67085 Strasbourg (France); Elkaim, R. [Institut National de la Sante et de la Recherche Medicale, 67085 Strasbourg (France); Hildebrand, G. [IBA e.V., Department of Biomaterials, Rosenhof, D-37308 Heilbad Heiligenstadt (Germany)

    2005-07-30

    We review the progress made by us using pulsed laser deposition (PLD) of two bioactive calcium phosphates: octacalcium phosphate (OCP) and Mn doped carbonated hydroxyapatite (Mn-CHA). Coatings of these materials well suited for biomimetic medical prostheses and pivots were synthesized on titanium substrates with a pulsed KrF* UV laser source. The best deposition conditions for Mn-CHA thin films were 13 Pa O{sub 2}, 400 deg. C with post heat treatment of 6 h in air enriched with water vapours. The coatings are stoichiometric and crystalline. For OCP, deposition at 150 deg. C in 50 Pa water vapor atmosphere, post treated by 6 h annealing in hot flux of water vapours, resulted in stoichiometric, but poorly-crystallized films. Degradation tests show different behavior for the OCP and Mn-CHA coatings. In vitro cell growth shows excellent adherence and biocompatibility of osteoblasts and fibroblasts in both OCP and Mn-CHA coatings. Human osteoblasts display normal proliferation and viability, and good differentiation behaviour.

  7. Calcium phosphate thin films synthesized by pulsed laser deposition: Physico-chemical characterization and in vitro cell response

    International Nuclear Information System (INIS)

    We review the progress made by us using pulsed laser deposition (PLD) of two bioactive calcium phosphates: octacalcium phosphate (OCP) and Mn doped carbonated hydroxyapatite (Mn-CHA). Coatings of these materials well suited for biomimetic medical prostheses and pivots were synthesized on titanium substrates with a pulsed KrF* UV laser source. The best deposition conditions for Mn-CHA thin films were 13 Pa O2, 400 deg. C with post heat treatment of 6 h in air enriched with water vapours. The coatings are stoichiometric and crystalline. For OCP, deposition at 150 deg. C in 50 Pa water vapor atmosphere, post treated by 6 h annealing in hot flux of water vapours, resulted in stoichiometric, but poorly-crystallized films. Degradation tests show different behavior for the OCP and Mn-CHA coatings. In vitro cell growth shows excellent adherence and biocompatibility of osteoblasts and fibroblasts in both OCP and Mn-CHA coatings. Human osteoblasts display normal proliferation and viability, and good differentiation behaviour

  8. 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

  9. 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.

  10. 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...

  11. Persistence of microbial and chemical pig manure markers as compared to faecal indicator bacteria survival in freshwater and seawater microcosms.

    Science.gov (United States)

    Solecki, O; Jeanneau, L; Jardé, E; Gourmelon, M; Marin, C; Pourcher, A M

    2011-10-01

    Natural seawater and freshwater microcosms inoculated with pig manure were set up to determine the persistence of pig faecal microbial and chemical markers in these two types of surface water. The concentrations of Lactobacillus amylovorus, the Bacteroidales Pig-2-Bac 16S rRNA genetic marker, five stanols and the evolution of two ratios of stanols, R1 (coprostanol to the sum of coprostanol and 24-ethylcoprostanol) and R2 (sitostanol to coprostanol) were analyzed during two months along with the concentration of Faecal Indicator Bacteria (FIB). Pig manure was inoculated to unfiltered water microcosms incubated aerobically at 18 °C in the dark. The faecal contamination load represented by the concentrations of culturable Escherichia coli and/or enterococci remained for two months in the freshwater and seawater microcosms water column. These concentrations followed a biphasic decay pattern with a 97% reduction of the initial amount during a first rapid phase (amylovorus marker and five stanols persisted as long as the indicators in both treatments. The Pig-2-Bac marker persisted 20 and 27 days in seawater and freshwater, respectively. The ratios R1 and R2 were in the range specific to pig manure until day 6 in both types of water. These results indicate that Pig-2-Bac, L. amylovorus and stanol ratios might be used in combination to complement FIB testing to determine the pig source of fecal pollution. However, stanol ratios are to be used when the time point of the discharge is known. PMID:21745675

  12. Effect of addition of nano-hydroxyapatite on physico-chemical and antibiofilm properties of calcium silicate cements

    Science.gov (United States)

    GUERREIRO-TANOMARU, Juliane Maria; VÁZQUEZ-GARCÍA, Fernando Antonio; BOSSO-MARTELO, Roberta; BERNARDI, Maria Inês Basso; FARIA, Gisele; TANOMARU, Mario

    2016-01-01

    ABSTRACT Objective Mineral Trioxide Aggregate (MTA) is a calcium silicate cement composed of Portland cement (PC) and bismuth oxide. Hydroxyapatite has been incorporated to enhance mechanical and biological properties of dental materials. This study evaluated physicochemical and mechanical properties and antibiofilm activity of MTA and PC associated with zirconium oxide (ZrO2) and hydroxyapatite nanoparticles (HAn). Material and Methods White MTA (Angelus, Brazil); PC (70%)+ZrO2 (30%); PC (60%)+ZrO2 (30%)+HAn (10%); PC (50%)+ZrO2 (30%)+HAn (20%) were evaluated. The pH was assessed by a digital pH-meter and solubility by mass loss. Setting time was evaluated by using Gilmore needles. Compressive strength was analyzed by mechanical test. Samples were radiographed alongside an aluminum step wedge to evaluate radiopacity. For the antibiofilm evaluation, materials were placed in direct contact with E. faecalis biofilm induced on dentine blocks. The number of colony-forming units (CFU mL-1) in the remaining biolfilm was evaluated. The results were submitted to ANOVA and the Tukey test, with 5% significance. Results There was no difference in pH levels of PC+ZrO2, PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p>0.05) and these cements presented higher pH levels than MTA (p<0.05). The highest solubility was observed in PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p<0.05). MTA had the shortest initial setting time (p<0.05). All the materials showed radiopacity higher than 3 mmAl. PC+ZrO2 and MTA had the highest compressive strength (p<0.05). Materials did not completely neutralize the bacterial biofilm, but the association with HAn provided greater bacterial reduction than MTA and PC+ZrO2 (p<0.05) after the post-manipulation period of 2 days. Conclusions The addition of HAn to PC associated with ZrO2 harmed the compressive strength and solubility. On the other hand, HAn did not change the pH and the initial setting time, but improved the radiopacity (HAn 10%), the final setting time

  13. 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.

  14. A new method for the study of the formation and transformation of calcium phosphate precipitates: effects of several chemical agents and Chinese folk medicines.

    Science.gov (United States)

    Hidaka, S; Abe, K; Liu, S Y

    1991-01-01

    A simple method of assaying the formation of amorphous calcium phosphate and its transformation to hydroxyapatite using a conventional pH meter and recorder is described. Its validity was confirmed by direct assay of calcium consumption with atomic absorption spectrophotometry. The method was used to study substances which influence the formation of amorphous calcium phosphate and its transformation to hydroxyapatite, such as albumin, casein, chondroitin sulphate, phospholipid, ATP, Mg2+, Sr2+, pyrophosphate and several Chinese folk medicines. PMID:1849399

  15. 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。

  16. Stable isotopes and chemical composition at different spatial scales indicate sink function of eroded OC in a tropical catchment

    Science.gov (United States)

    Chaplot, V.; Rumpel, C.; Fontaine, S.; Bouahom, B.; Valentin, C.

    2009-04-01

    Our objective was to evaluate the fate of eroded carbon at landscape level in a steep slope area of the Mekong basin submitted to traditional slash-and-burn (SAB) agriculture. We monitored carbon erosion at different spatial scales ranging from 1m² (micro-plot level) installed within a hillslope to 1×107 m² (watershed). Samples were taken throughout the 2003 rainy season, in order to quantitatively assess the fate of eroded OC. Laboratory analysis of the chemical composition of eroded OC by analysis for its elemental, istotopic (13C, 15N, 14C) and bulk chemical composition were performed to assess potential microbial decomposition of eroded sediment during transport and sedimentation. Our data show, that 92.7% of eroded OC were sedimented at a distance lower that 1.5m from its source. Analysis of the composition of eroded organic matter at different scales showed a significant decrease of the C/N ratio and an enrichment of 13C and 15N isotopes, which occurred within the hillslope and in first order reaches. These changes were interpreted as resulting from OC decomposition and used to assess the CO2 emissions, which might have occurred during the erosion process. Our results indicate, that within the hillslope, potential CO2 emissions with 0.43 gCm-2y-1 would be 3.3 times higher than the OC exports by water erosion but represented about 10% only of the OC deposited. Potential CO2 emissions during the transport from the hillslope to the watershed outlet would represent 14% of total eroded OC. Based on these results, we suggest that erosion induced OC sequestration amounts to 43 gCm-2y-1 in the hillslope and, 33 gCm-2y-1 at the watershed level.

  17. Preliminary geothermal model of volcanic areas in Ecuador based on chemical and isotopic investigation of thermal indicators

    International Nuclear Information System (INIS)

    Since 1986, the waters and gases of eight geothermal areas have been sampled and analysed to establish their chemical and isotopic composition. In Chachimbiro and Cuicocha 18O enrichment up to 5% and deuterium enrichment up to 20% have been observed. The isotopic variations seen in Chachimbiro could be explained by hypothetical deep geothermal water with a temperature range from 240 deg. C to surface temperature. The values observed in Cuicocha, on the other hand, are due to mixing of hot groundwater with fresh lagoon water. In other areas, the isotopic composition of the thermal waters basically corresponds to that of meteoric water falling from various altitudes ranging from 2500 to 4200 m above sea level. The Na/K ratios indicate reservoir temperatures for the chloride waters emerging in the Chachimbiro, Cuenca and Papallacta geothermal areas of approximately 240 deg. C, 210 deg. C and 200 deg. C, respectively. From the data on the Chalupas caldera it is impossible to construct any reasonable theory regarding the presence of a deep, high-temperature aquifer. Tungurahua volcano samples consist of sulphuric acid water with an isotopic composition similar to waters evaporating at about 200 deg. C. The number of samples from the Chimborazo area was too low to justify any assumptions about the thermal characteristics of the water. The waters in Tufino originate in surface aquifers modified by hot gases registering 230 deg. C on the geothermometers. (author). 24 refs, 12 figs, 1 tab

  18. 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 ...

  19. 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...

  20. 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 ...

  1. Impact of environmental chemicals, sociodemographic variables, depression, and clinical indicators of health and nutrition on self-reported health status

    Science.gov (United States)

    Public health researchers ideally integrate social, environmental, and clinical measures to identify predictors of poor health. Chemicals measured in human tissues are often evaluated in relation to intangible or rare health outcomes, or are studied one chemical at a time. Using ...

  2. 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...

  3. Urine risk factors in children with calcium kidney stones and their siblings.

    Science.gov (United States)

    Bergsland, Kristin J; Coe, Fredric L; White, Mark D; Erhard, Michael J; DeFoor, William R; Mahan, John D; Schwaderer, Andrew L; Asplin, John R

    2012-06-01

    Calcium nephrolithiasis in children is increasing in prevalence and tends to be recurrent. Although children have a lower incidence of nephrolithiasis than adults, its etiology in children is less well understood; hence, treatments targeted for adults may not be optimal in children. To better understand metabolic abnormalities in stone-forming children, we compared chemical measurements and the crystallization properties of 24-h urine collections from 129 stone formers matched to 105 non-stone-forming siblings and 183 normal, healthy children with no family history of stones, all aged 6 to 17 years. The principal risk factor for calcium stone formation was hypercalciuria. Stone formers have strikingly higher calcium excretion along with high supersaturation for calcium oxalate and calcium phosphate, and a reduced distance between the upper limit of metastability and supersaturation for calcium phosphate, indicating increased risk of calcium phosphate crystallization. Other differences in urine chemistry that exist between adult stone formers and normal individuals such as hyperoxaluria, hypocitraturia, abnormal urine pH, and low urine volume were not found in these children. Hence, hypercalciuria and a reduction in the gap between calcium phosphate upper limit of metastability and supersaturation are crucial determinants of stone risk. This highlights the importance of managing hypercalciuria in children with calcium stones. PMID:22358148

  4. 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)

  5. Chemical composition of the thermomineral waters of Josanicka Banja spa as an origin indicator, balneological valorization and geothermal potential

    Directory of Open Access Journals (Sweden)

    Milenić Dejan R.

    2015-01-01

    Full Text Available The chemical composition of the groundwater is directly dependent on the geological structure, hydrogeological and hydrochemical characteristics and as such it represents an output result of all the factors and processes which take place in the environment within which they were formed. The chemical composition of thermomineral waters often represents a crucial factor in determining the origin, balneological valorization and geothermal potential of the resources. This work presents the analysis of origin, belneological valorization and geothermal potential of Josanicka Banja spa, on the basis of the results gained through making the analyisis of chemical contents of the thermomineral waters which occur in the area. The ratio of concentrations of specific chemical components in the thermomineral waters of Josanicka Banja has served as the basic tool for ascertaining the origin of these waters. On the basis of the analysis of the main anion-cation and gas compositions as well as the contents of specific micro-components, a balneological valorization of these resources has been carried out. Apart from that this work also presents the calculation of the expected temperatures in the primary geothermal reservoir, which was carried out on the basis of the results of chemical analysis of thermomineral waters that occur in the area. Geothermal potential of about 4 MWt and significant contents of balneologically active components of the chemical composition of these waters, open up a possibility for their multi-purpose use, which is also presented in the work. [Projekat Ministarstva nauke Republike Srbije, br. TR 33053

  6. 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 ...

  7. 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

  8. The Integrated Calcium II Triplet as a Metallicity Indicator: Comparisons with High Resolution [Fe/H] in M31 Globular Clusters

    CERN Document Server

    Sakari, Charli M

    2015-01-01

    Medium resolution (R=4,000 to 9,000) spectra of the near infrared Ca II lines (at 8498, 8542, and 8662 A) in M31 globular cluster integrated light spectra are presented. In individual stars the Ca II triplet (CaT) traces stellar metallicity; this paper compares integrated CaT strengths to well determined, high precision [Fe/H] values from high resolution integrated light spectra. The target globular clusters cover a wide range in metallicity (from [Fe/H] = -2.1 to -0.2). While most are older than 10 Gyr, some may be of intermediate age (2-6 Gyr). A handful (3-6) have detailed abundances (e.g. low [Ca/Fe]) that indicate they may have been accreted from dwarf galaxies. Using various measurements and definitions of CaT strength, it is confirmed that for GCs with [Fe/H] < -0.4 and older than 2 Gyr the integrated CaT traces cluster [Fe/H] to within about 0.2 dex, independent of age. CaT lines in metal rich GCs are very sensitive to nearby atomic lines (and TiO molecular lines in the most metal rich GCs), largel...

  9. Obtainment of calcium carbonate from mussels shell; Obtencao de carbonato de calcio a partir de conchas de mariscos

    Energy Technology Data Exchange (ETDEWEB)

    Hamester, M.R.R.; Becker, D., E-mail: michele.rosa@sociesc.org.b [Sociedade Educacional de Santa Catarina (SOCIESC), Joinville, SC (Brazil). Mestrado Profissional em Engenharia Mecanica

    2010-07-01

    The mussels and oyster shell are discarded at environment, and this accumulation is causing negative consequences to ecosystem. Calcium carbonate is main constituent of the shell chemical composition. Aiming to reduce environmental aggression and generate income to shellfish producer, there was the possibility of using these shells as an alternative to commercial calcium carbonate. For this physics, chemicals and thermal properties were evaluated, using X-ray fluorescence, thermogravimetric analysis, size distribution, abrasiveness and scanning electronic microscopy. The results indicate that mussels shells have an initial degradation temperature higher than commercial calcium carbonate e same lost weight behavior and 95% of shell chemical composition is calcium carbonate. The sample size distribution was influenced by grinding condition and time as well as its abrasiveness. (author)

  10. Chemical alteration of cement materials in a radioactive waste repository environment. 1. Thermodynamic modelling for the dissolution and precipitation of calcium silicate hydrates

    International Nuclear Information System (INIS)

    Cementitious material, a potential waste packaging and backfilling material for the disposal of radioactive waste, is expected to provide both physical and chemical containment. In particular the ability to provide high-pH conditions, which depends on the solubility of the constituent hydrated minerals in cement matrices, is a very important parameter when considering the release of radionuclides from radio active wastes. For long-term safety assessment, it is necessary to develop a series of predictive calculation models. Several models have been proposed for the incongruent dissolution of calcium silicate hydrate (C-S-H) gel, which is the principal product of hydrated cement phases. In the repository, the re-precipitation of minerals would follow their dissolution when an equilibrated solution moves to the other regions and equilibrates with the constituent minerals there. However, previous models have not yet adequately quantitatively evaluated the re-precipitation or interaction of other minerals with the dissolution of C-S-H gel. In this study, therefore, a thermodynamic dissolution and precipitation model of C-S-H gel is proposed assuming a binary non-ideal solid solution of Ca(OH)2 and Si02. Dissolution and precipitation experiments on C-S-H gel were performed. C-S-H precipitates were prepared using two techniques. One was based on hydrolysis in a mixture of Ca and Si solutions and produced homogeneous gels. With the other technique, precipitates were prepared by contacting Ca(OH)2 solution with C-S-H gel with low Ca/Si ratios (0.47, 0.65, 0.9). The results were well predicted by the proposed model. Dissolution experiments on C-S-H gel coexisting with ettringite were also carried out. At Ca/Si>l.2 in C-S-H gel, the equilibrated pH and Ca and Si concentrations are nearly the same as those for C-S-H gel alone. At lower Ca/Si, interaction between ettringite and C-S-H dissolution was observed more clearly. The measured pH and Ca and Si concentrations were

  11. Calcium Forms,Subcelluar Distribution and Ultrastructure of Pulp Cells as Influenced by Calcium Deficiency in Apple (Malus pumila) Fruits

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-hui; ZHOU Wei

    2004-01-01

    Calcium in Red Fuji and Starkrimson apples during storage were fractionated by sequent extracting. Localization and distribution of calcium and influence of calcium nutrition on cell ultrastructure were observed by transmission electron microscopy combined with in situ precipitation of calcium with an improved method of potassium pyroantimonate technique. Results indicated that spraying calcium solution on surface of young fruits increased contents of calcium in all forms. During storage, contents of soluble calcium and pectic calcium declined and thosein calcium phosphate, calcium oxalate and calcium silicate increased. Calcium contents of Red Fuji in all forms were higher than those of Starkrimson, indicating that calcium accumulating capability of Red Fuji fruits preceded that of Starkrimson. Under transmission electron microscopy, calcium antimonite precipitates (CaAP) was mainly distributed in cell wall, tonoplast, nuclear membrane and nucleoplasm,much more CaAP deposited in vacuole. Calcium deficiency during storage leads to decrease of CaAP in locations mentioned above, disappearance of compartmentation, and entrance of CaAP to cytoplasm. Transformation from soluble calcium and pectic calcium to calcium phosphate,oxalate and damages of biomembranes structuraly and functionally resulted from calcium deficiency during storage were the crucial causation of physiological disorder.

  12. ZrO{sub 2} thin films to improve the chemical resistance of calcium matt glazes; Capas finas de ZrO{sub 2} para mejorar la resistencia quimica de los vidriados mates de calcio

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, M. D.; Mestre, S.; Orts, M. J.; Blasco, E.

    2012-11-01

    The chemical resistance of ceramic glazes susceptible to it, and more specifically the glazes formulated with a calcium matt frit, is enhanced by depositing on the surface a thin layer of zirconium oxide. A stabilized zirconia sol is the precursor of the layer, which is deposited by spray painting over the glaze, and with a mild heat treatment (T{sub m}ax {approx}{approx} 400 degree centigrade) is transformed into ZrO{sub 2} and anchored to the glazes surface. Chemical resistance tests show that the protected glaze does not suffer a visually significant attack by concentrated hydrochloric acid, conditions under which the same glaze without the coating is severely damaged. The used precursor generates a zirconium oxide layer that protects the underlying glaze, so that the chemical attack by the hydrochloric acid is confined to cracks and discontinuities in the deposited layer. (Author) 22 refs.

  13. 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. ...

  14. 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 ...

  15. 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 ...

  16. 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.

  17. Preliminary studies of quality assessment of aquatic environments from Cluj suburban areas, based on some invertebrates bioindicators and chemical indicators

    OpenAIRE

    Gheorghe Stan; Laurenţiu C. Stoian; A. Bianca Badea; Andrea Gagyi-Palffy

    2010-01-01

    Systematic categories of invertebrates bioindicators correlated with some chemical parameters,were an effective way to characterize the quality of lotic (Someş River) and lentic (Lake Gilău) aquatic environment from Cluj-Napoca area. Invertebrate fauna was represented by species belonging to the following dominant systematic categories: Nematoda, Annelida, Crustacea and Insecta. This paper containsalso some preliminary data on the bioindicators species belonging to Protozoa phylum. Dominant g...

  18. Persistence of microbial and chemical pig manure markers as compared to faecal indicator bacteria survival in freshwater and seawater microcosms

    OpenAIRE

    2011-01-01

    Natural seawater and freshwater microcosms inoculated with pig manure were set up to determine the persistence of pig faecal microbial and chemical markers in these two types of surface water. The concentrations of Lactobacillus amylovorus, the Bacteroidales Pig-2-Bac 165 rRNA genetic marker, five stanols and the evolution of two ratios of stanols, R(1) (coprostanol to the sum of coprostanol and 24-ethylcoprostanol) and R(2) (sitostanol to coprostanol) were analyzed during two months along wi...

  19. Karrikins Identified in Biochars Indicate Post-Fire Chemical Cues Can Influence Community Diversity and Plant Development

    Science.gov (United States)

    Kochanek, Jitka; Flematti, Gavin R.

    2016-01-01

    Background Karrikins are smoke-derived compounds that provide strong chemical cues to stimulate seed germination and seedling growth. The recent discovery in Arabidopsis that the karrikin perception system may be present throughout angiosperms implies a fundamental plant function. Here, we identify the most potent karrikin, karrikinolide (KAR1), in biochars and determine its role in species unique plant responses. Methods Biochars were prepared by three distinct commercial-scale pyrolysis technologies using systematically selected source material and their chemical properties, including karrikinolide, were quantified. Dose-response assays determined the effects of biochar on seed germination for two model species that require karrikinolide to break dormancy (Solanum orbiculatum, Brassica tourneforttii) and on seedling growth using two species that display plasticity to karrikins, biochar and phytotoxins (Lactuca sativa, Lycopersicon esculentum). Multivariate analysis examined relationships between biochar properties and the plant phenotype. Findings and Conclusions Results showed that karrikin abundant biochars stimulated dormant seed germination and seedling growth via mechanisms analogous to post-fire chemical cues. The individual species response was associated with its sensitivity to karrikinolide and inhibitory compounds within the biochars. These findings are critical for understanding why biochar influences community composition and plant physiology uniquely for different species and reaffirms that future pyrolysis technologies promise by-products that concomitantly sequester carbon and enhance plant growth for ecological and broader plant related applications. PMID:27536995

  20. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  1. Test-methods of chemical analysis with visual and scanner indication in ecoanalytical monitoring of nature reservoirs of Kirovograd region

    Directory of Open Access Journals (Sweden)

    Y. V. Bokhan

    2007-03-01

    Full Text Available The features of test analysis with visual and scanner indication for the exposure and semiquantitative determination of general pollutants and indices of water bodies’ quality are considered. Evaluation of some metrological descriptions of the known test-methods of pH determination, concentrations of the dissolved oxygen, nitrate- and phosphate-ions, ions of iron with visual and computer scanner-technologies using is offered.

  2. Production induced boiling and cold water entry in the Cerro Prieto geothermal reservoir indicated by chemical and physical measurements

    Energy Technology Data Exchange (ETDEWEB)

    Grant, M.A. (DSIR, Wellington, New Zealand); Truesdell, A.H.; Manon, A.

    1981-01-01

    Chemical and physical data suggest that the relatively shallow western part of the Cerro Prieto reservoir is bounded below by low permeability rocks, and above and at the sides by an interface with cooler water. There is no continuous permeability barrier around or immediately above the reservoir. Permeability within the reservoir is dominantly intergranular. Mixture with cooler water rather than boiling is the dominant cooling process in the natural state, and production causes displacement of hot water by cooler water, not by vapor. Local boiling occurs near most wells in response to pressure decreases, but no general vapor zone has formed.

  3. Effects of Adding Chymosin to Milk on Calcium Homeostasis

    DEFF Research Database (Denmark)

    Møller, Ulla Kristine; Jensen, Lars Thorbjørn; Mosekilde, Leif;

    2014-01-01

    Calcium intake and absorption is important for bone health. In a randomized double-blind cross-over trial, we investigated effects of adding chymosin to milk on the intestinal calcium absorption as measured by renal calcium excretion and indices of calcium homeostasis. The primary outcome of the...

  4. Chemical composition of Clarias Lazera (cuv and val., 1840) as an indicator of fish raising in treated sewage effluents

    International Nuclear Information System (INIS)

    The present study is one of the pioneer studies dealing with the possibility of growing fish in treated sewage water in Sudan. Khartoum sewage treatment plant - Green Belt area - was the main study site for this work, where fish was some how introduced to the canal which receives water from the last stage of treatment. Fish have reached large sizes and numbers, they are highly consumed by people of the area and widely marketed in the nearby localities. So this study aimed to discuss the potential health associated with the utilization of such fish for food, throwing light, on the advantages and disadvantages of fish culture in treated sewage effluent. The research was directed towards the study of the chemical composition of Clarias lazera (Cuv. and Val., 1840) (Garmout fish) being the only fish species in the area during the course of this study . Fish samples were collected from the Green Belt and the White Nile at the vicinity of Jebel Aulia reservoir which was taken as a control area for (April 1995 - April 1996). Basic biology was studies for each specimen, the concentrations of some of the hazardous and potentially hazardous heavy metals were investigated in the flesh of 30, randomly selected fish samples from both study sites, beside the major chemical body constituents : fats, proteins, moisture and ash in all specimens, to determine the quality of the flesh> Data obtained was analyzed, trying to correlate fish chemical composition to the surrounding environment. Treated sewage-fish showed higher weights and lengths than natural water-fish from the White Nile. Most of the hazardous metals investigated in the muscle tissues of treated sewage-fish were found to be of insignificant variation from that of natural water-fish (Mercury and Lead). They were found to be at lower levels than what is recommended by the International Agencies human consumption. The essential micronutrients for fish like Copper, Ferric (Iron) and Zinc showed significantly higher levels

  5. 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

  6. Mechanical and Thermal Dehydrogenation of the Mechano-Chemically Synthesized Calcium Alanate (Ca(AlH42 and Lithium Chloride (LiCl Composite

    Directory of Open Access Journals (Sweden)

    Robert A. Varin

    2015-06-01

    Full Text Available LiAlH4 and CaCl2 were employed for mechano-chemical activation synthesis (MCAS of Ca(AlH42 and LiCl hydride composite. After short ball milling time, their X-ray diffraction (XRD peaks are clearly observed. After ball milling for a longer duration than 0.5 h, the CaAlH5 diffraction peaks are observed which indicates that Ca(AlH42 starts decomposing during ball milling into CaAlH5+Al+1.5H2. It is estimated that less than 1 wt % H2 was mechanically dehydrogenated in association with decomposition reaction. After 2.5 h of ball milling, no Ca(AlH42 diffraction peaks were observed on XRD patterns which suggests that Ca(AlH42 was decomposed. Thermal behavior of ball milled powders, which was investigated by thermal gravimetric analysis (TGA and differential scanning calorimetry (DSC, indicates that a certain fraction of Ca(AlH42 could have been disordered/amorphized during ball milling being undetectable by XRD. The apparent activation energy for the decomposition of Ca(AlH42 and CaAlH5 equals 135 kJ/mol and 183 kJ/mol, respectively.

  7. Effects of oil sands related aquatic reclamation on yellow perch (Perca flavescens). 2. Chemical and biochemical indicators of exposure to oil sands related waters

    International Nuclear Information System (INIS)

    The impact that oil sands related waters may have on aquatic ecosystems and fish was examined. Regardless of the oil sands tailing reclamation method, the quality of surface waters will be affected by elevated salinity and organic acids as well as by increased concentrations of polycyclic aromatic hydrocarbons (PAHs). The study determined that since surface waters will eventually impact on fish, it would be useful to have a suite of biochemical and chemical indicators of exposure to families of compounds associated with oil sands related waters. Two indicators, mixed-function oxygenase (MFO) activity and bile PAH equivalent concentration are frequently used to quantify exposure of fishes to petroleum hydrocarbons. Adult yellow perch were stocked into experimental ponds containing oil sands related waters. After 5 and 11 months, the usefulness of MFO enzymes, conjugation enzymes, bile PAH metabolite concentrations and plasma steroid hormones in yellow perch were examined. The potential of these biochemical and chemical endpoints as predictive indicators of physiological and population-level impacts was examined. It was shown that MFO activity and bile PAH equivalents were good indicators of exposure to oil sands related waters, but they were not predictive of physiological endpoints. This suggests that physiological endpoints were influenced by ecological and not chemical factors. 28 refs., 1 tab., 4 figs

  8. Black poplar-tree (Populus nigra L.) bark as an alternative indicator of urban air pollution by chemical elements

    International Nuclear Information System (INIS)

    Capabilities of black poplar-tree (Populus nigra L.) bark as a biomonitor of atmospheric air pollution by chemical elements were tested against epiphytic lichens Xanthoria parietina (L.) and Physcia adscendens (Fr.). Concentrations of 40 macro and trace elements were determined using epicadmium and instrumental NAA. The data obtained were processed using non-parametric tests. A good correlation was found between concentrations of majority of elements in bark and lichens. On the accumulation capability bark turned out to be competitive with both lichens examined. The main inorganic components of black poplar-tree bark were revealed. A substrate influence on the concentrations of some elements in epiphytic lichens was established. An optimized procedure of bark pre-irradiation treatment was suggested. (author)

  9. A petrographic, chemical, and isotopic study of calcium-aluminum-rich inclusions and aluminum-rich chondrules from the Axtell (CV3) chondrite

    OpenAIRE

    Srinivasan, G.; Huss, G. R.; Wasserburg, G. J.

    2000-01-01

    Petrographic, compositional, and isotopic characteristics were studied for three calcium-aluminum-rich inclusions (CAIs) and four plagioclase-bearing chondrules (three of them Al-rich) from the Axtell (CV3) chondrite. All seven objects have analogues in Allende (CV3) and other primitive chondrites, yet Axtell, like most other chondrites, contains a distinctive suite of CAIs and chondrules. In common with Allende CAIs, CAIs in Axtell exhibit initial ^(26)Al/^(27)Al ratios ((^(26)Al/^(27)Al)0) ...

  10. Productivity in Physical and Chemical Science Predicts the Future Economic Growth of Developing Countries Better than Other Popular Indices

    OpenAIRE

    Jaffe, Klaus; Caicedo, Mario; Manzanares, Marcos; Gil, Mario; Rios, Alfredo; Florez, Astrid; Montoreano, Claudia; Davila, Vicente

    2013-01-01

    Scientific productivity of middle income countries correlates stronger with present and future wealth than indices reflecting its financial, social, economic or technological sophistication. We identify the contribution of the relative productivity of different scientific disciplines in predicting the future economic growth of a nation. Results show that rich and poor countries differ in the relative proportion of their scientific output in the different disciplines: countries with higher rel...

  11. Changes in formation gas composition and isotope content as indicators of unsaturated-zone chemical reactions related to recharge events

    International Nuclear Information System (INIS)

    The constituent composition and carbon and oxygen isotopes for CO2 in unsaturated-zone gases have been utilized to provide an independent means of determining what chemical reactions occurred during an extended artificial recharge experiment on the High Plains of Texas. Gas samples were collected from a sample point at a depth of 16 metres beneath a waterspreading basin to see what effect recharging water had on the unsaturated-zone atmosphere. Two different systems, one open and one closed, were sampled during this study. The 13C, 18O, Psub(CO2), and N/Ar data for gas collected during a 1975 experiment show the influence of unsaturated-zone gases being displaced by recharging waters, the trend towards equilibration with dissolved atmospheric gases as the sampling point is submerged by rising waters, the onset of a reducing environment and, following the termination of recharge, the slow recovery of the gas composition to pre-recharge conditions. The 13C content of the CO2 in the gases varied from -18.06% for the pre-recharge formation gas, to -10.01% for gases approaching equilibrium with dissolved atmospheric gases, to -38.01% for a CO2 produced from methane generated in a reducing evironment. The log Psub(CO2) for the above samples varied from -2.10 to -3.02 to -4.18 atmospheres, respectively. Recovery to pre-recharge unsaturated-zone atmospheric conditions took many months following the termination of recharge. (author)

  12. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium...

  13. Health indices of the rural population living in the area affected by the Krasnoyarsk mining and chemical combine

    International Nuclear Information System (INIS)

    Radioactive contamination of the floodplain of the Yenisei River with the wastes dumped by the Krasnoyarsk Mining, and Chemical Combine (MCC) might cause external and internal irradiation of a large part of rural population inhabiting the banks of the Yenisei. Due the lack of comprehensive data on the dose status and doses received by the population, the health parameters of the population were studied by comparing the recorded incidences of diseases and mortality in the areas located at different distances from the MCC, in the periods before and after the MCC was put into operation, and in different age groups. Also studied were territorial differences in the immunologic and immunogenetic statuses of some groups of population. It has been found out that in the district subjected to radioactive contamination (RAC-districts) there are characteristic shifts in the pathologies that are the main markers of the radiation factor. With possible accumulation of radiation doses the shifts become more distinct, and with the distance from the MCC less distinct. Time and space gradients of the cancer morbidity and mortality rate in the RAC-area have been found. In the riverside settlements of the RAC-area the mortality from malignant neoplasms (MN) of blood, blood-forming organs, and lymphatic system is higher than in the settlements located farther from the Yenisei. As the distance from the MCC down the Yenisei gets longer, the mortality of children due to congenital developmental defects and leukaemia decreases. The space gradient has been also found for most somatic disorders originating from stressogenic (psycho-emotional strain) and immunodeficient states. Besides increased incidence of cancer, in the RAC-area there is a higher incidence of pathological states determined to a large extent genetically - complicated pregnancies and their outcome, mortinatality, and congenital developmental defects. Investigations of immunologic and immunogenetic statuses of the RAC

  14. Productivity in physical and chemical science predicts the future economic growth of developing countries better than other popular indices.

    Directory of Open Access Journals (Sweden)

    Klaus Jaffe

    Full Text Available Scientific productivity of middle income countries correlates stronger with present and future wealth than indices reflecting its financial, social, economic or technological sophistication. We identify the contribution of the relative productivity of different scientific disciplines in predicting the future economic growth of a nation. Results show that rich and poor countries differ in the relative proportion of their scientific output in the different disciplines: countries with higher relative productivity in basic sciences such as physics and chemistry had the highest economic growth in the following five years compared to countries with a higher relative productivity in applied sciences such as medicine and pharmacy. Results suggest that the economies of middle income countries that focus their academic efforts in selected areas of applied knowledge grow slower than countries which invest in general basic sciences.

  15. AQUATIC HEMIPTERAN DIVERSITY AS INDICATORS OF MORE ENVIRONMENTAL EXTREMES: RELATION TO TOLERANT OF SOME PHYSICO-CHEMICAL CHARACTERISTICS OF WATER.

    Directory of Open Access Journals (Sweden)

    P P Joshi

    2012-01-01

    Full Text Available Seven families of aquatic bug of order Hemiptera belonging to neoptera of division Exopterygota occur in Nilona dam, Yavatmal were recorded in the year 2011. Behavior is surprisingly diagnostic with reference to species diversity and nature. Observe their habit, habitat selection and nature of feeding. On the basis of the results the indicator values have been analyzed and it is clear that Water boatman and Water striders can be tolerating more acidic pH. The low D.O., high CO2 and high chloride concentration have been tolerated only by Giant water bug. The high turbidity concentration can be faced successfully by Water striders. Expect Pigmy water bug the second range of pH, D.O., CO2, Chloride and turbidity concentration have been almost tolerated by all species. The third range of all the parameters can easily be tolerated by all.

  16. Stability and maturity of biowaste composts derived by small municipalities: Correlation among physical, chemical and biological indices.

    Science.gov (United States)

    Oviedo-Ocaña, E R; Torres-Lozada, P; Marmolejo-Rebellon, L F; Hoyos, L V; Gonzales, S; Barrena, R; Komilis, D; Sanchez, A

    2015-10-01

    Stability and maturity are important criteria to guarantee the quality of a compost that is applied to agriculture or used as amendment in degraded soils. Although different techniques exist to evaluate stability and maturity, the application of laboratory tests in municipalities in developing countries can be limited due to cost and application complexities. In the composting facilities of such places, some classical low cost on-site tests to monitor the composting process are usually implemented; however, such tests do not necessarily clearly identify conditions of stability and maturity. In this article, we have applied and compared results of stability and maturity tests that can be easily employed on site (i.e. temperature, pH, moisture, electrical conductivity [EC], odor and color), and of tests that require more complex laboratory techniques (volatile solids, C/N ratio, self-heating, respirometric index, germination index [GI]). The evaluation of the above was performed in the field scale using 2 piles of biowaste applied compost. The monitoring period was from day 70 to day 190 of the process. Results showed that the low-cost tests traditionally employed to monitor the composting process on-site, such as temperature, color and moisture, do not provide consistent determinations with the more complex laboratory tests used to assess stability (e.g. respiration index, self-heating, volatile solids). In the case of maturity tests (GI, pH, EC), both the on-site tests (pH, EC) and the laboratory test (GI) provided consistent results. Although, stability was indicated for most of the samples, the maturity tests indicated that products were consistently immature. Thus, a stable product is not necessarily mature. Conclusively, the decision on the quality of the compost in the installations located in developing countries requires the simultaneous use of a combination of tests that are performed both in the laboratory and on-site. PMID:26216503

  17. 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

  18. The applied indicators of water quality may underestimate the risk of chemical exposure to human population in reservoirs utilized for human supply-Southern Brazil.

    Science.gov (United States)

    Dos Santos, Debora Regina; Yamamoto, Flávia Yoshie; Filipak Neto, Francisco; Randi, Marco Antônio Ferreira; Garcia, Juan Esquivel; Costa, Daniele Dietrich Moura; Liebel, Samuel; Campos, Sandro Xavier; Voigt, Carmen Lúcia; de Oliveira Ribeiro, Ciro Alberto

    2016-05-01

    The knowledge concerning associations between chronic chemical exposure and many disorders with complex etiology involving gene-environment interactions is increasing, and new methods must be developed to improve water quality monitoring. The complexity of chemical mixtures in polluted aquatic environments makes the evaluation of toxic potential in those sites difficult, but the use of biomarkers and bioindicators has been recognized as a reliable tool to assess risk of exposure to biota and also the human population. In order to evaluate the use of fish and biomarkers to assess toxic potential and bioavailability of chemicals in human-related hydric resources, an in situ experiment was accomplished in two water reservoirs designated for human supply, which were previously evaluated by the local environmental regulatory agency through a set of physical, chemical, and classical biological parameters. Molecular, biochemical, and morphological biomarkers were performed in caged Oreochromis niloticus kept for 6 months in the studied reservoirs to assess potentially useful biomarkers to evaluate the quality of water for human supply. Chemical analysis of toxic metals in liver and muscle and polycyclic aromatic hydrocarbons (PAHs) in bile was considered to assess the bioavailability of pollutants and highlight human activity impact. The reservoir previously classified by a governmental agency as less impacted presented more risk of exposure to biota. These results were supported by chemical analysis, vitellogenin expression, histopathological findings (gonads, liver, and gills), as well as indicators of neurotoxic effects and oxidative stress in liver. The inclusion of some biomarkers as parameters in regulatory monitoring programs in reservoirs designated for human supply is strongly suggested to evaluate the risks of exposure to the human population. Thus, a revision of the traditional biological and physicochemical analysis utilized to establish the conditions of

  19. Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning

    Directory of Open Access Journals (Sweden)

    Motahareh Soltani

    2016-08-01

    Full Text Available Objectives: Aluminium phosphide (AlP is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3, a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. Methods: This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Results: Activated charcoal significantly reduced the volume of released gas (P <0.01. Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01. A gaseous adduct was formed in the reaction between pure AlP and boric acid. Conclusion: These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning.

  20. Phosphocitrate inhibits mitochondrial and cytosolic accumulation of calcium in kidney cells in vivo.

    Science.gov (United States)

    Tew, W P; Malis, C D; Howard, J E; Lehninger, A L

    1981-09-01

    Synthetic 3-phosphocitrate, an extremely potent inhibitor of calcium phosphate crystallization as determined in a nonbiological physical-chemical assay, has many similarities to a mitochondrial factor that inhibits crystallization of nondiffracting amorphous calcium phosphate. In order to determine whether phosphocitrate can prevent uptake and crystallization of calcium phosphate in mitochondria in vivo, it was administered intraperitoneally to animals given large daily doses of calcium gluconate or parathyroid hormone, a regimen that causes massive accumulation and crystallization of calcium phosphate in the mitochondria and cytosol of renal tubule cells in vivo. Administration of phosphocitrate greatly reduced the net uptake of Ca2+ by the kidneys and prevented the appearance of apatite-like crystalline structures within the mitochondrial matrix and cytosol of renal tubule cells. Phosphocitrate, which is a poor chelator of Ca2+, did not reduce the hypercalcemia induced by either agent. These in vivo observations therefore indicate that phosphocitrate acts primarily at the cellular level to prevent the extensive accumulation of calcium phosphate in kidney cells by inhibiting the mitochondrial accumulation or crystallization of calcium phosphate. PMID:6946490

  1. Chemical and isotopic tracers indicating groundwater/surface-water interaction within a boreal lake catchment in Finland

    Science.gov (United States)

    Rautio, Anne; Korkka-Niemi, Kirsti

    2015-03-01

    Stable isotopes (δ 18O, δD), dissolved silica (DSi) concentration and major ion composition were used to indicate groundwater/surface-water interaction between the aquifers, the rivers and a lake in the high-latitude Lake Pyhäjärvi catchment in Finland. Significant differences were recorded in water chemistry between the groundwater and surface waters, especially in the stable isotope composition and DSi concentrations, which could thus be used as tracers. The baseline data on isotopic patterns and hydrogeochemistry in the hydrological cycle were provided by a 1-year monitoring survey in this snow-type catchment area. The proportions of groundwater in the rivers, the lake inshore area and in a groundwater abstraction plant were calculated using stable isotopes and DSi. Two inflowing rivers had distinct differences in their water chemistry. DSi has potential as a tracer in the river environment, whereas stable isotopes were more applicable in the lake environment. Locally, near the shoreline, the effect of discharging groundwater on the lake-water quality could clearly be observed. Furthermore, infiltration of the lake water into the aquifer could be observed near the pumping wells onshore. This infiltration presents a potential risk for the water quality of water supply (intake) wells. Frequent sampling is needed as part of the evaluation of the level of groundwater/surface-water interaction in snow-type catchments in order to estimate the magnitude of seasonal variation. In groundwater/surface-water interaction studies, spring thaw and high-precipitation events could be problematic, in terms of both sampling and interpreting results.

  2. 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 ...

  3. 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 ...

  4. 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 ...

  5. 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 ...

  6. 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 ...

  7. 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 ...

  8. Calcium waves along the cleavage furrows in cleavage-stage Xenopus embryos and its inhibition by heparin

    OpenAIRE

    1996-01-01

    Calcium signaling is known to be associated with cytokinesis; however, the detailed spatio-temporal pattern of calcium dynamics has remained unclear. We have studied changes of intracellular free calcium in cleavage-stage Xenopus embryos using fluorescent calcium indicator dyes, mainly Calcium Green-1. Cleavage formation was followed by calcium transients that localized to cleavage furrows and propagated along the furrows as calcium waves. The calcium transients at the cleavage furrows were o...

  9. Gravity, Calcium, And Bone: Update, 1989

    Science.gov (United States)

    Arnaud, Sara B.; Morey-Holton, Emily

    1992-01-01

    Report reviews short-term flight and ground-based experiments on effects of 1 g and 0 g on skeletal adaptation, calcium metabolism, and growth processes. Results indicate two principal components of calcium metabolism-calcium endocrine system and bone - respond within days to changes in orientation of body in gravitation and to weightlessness. Effects of spaceflight or bed rest on biomechanics of bones more severe than on total body bone mass.

  10. Familial hypocalciuric hypercalcemia and calcium sensing receptor

    DEFF Research Database (Denmark)

    Mrgan, Monija; Nielsen, Sanne; Brixen, Kim

    2014-01-01

    Familial hypocalciuric hypercalcemia (FHH) is a lifelong, benign autosomal dominant disease characterized by hypercalcemia, normal to increased parathyroid hormone level, and a relatively low renal calcium excretion. Inactivation of the calcium-sensing receptor in heterozygous patients results in...... FHH, while in homozygous patients as well as in compound heterozygous or dominant negative heterozygous patients, it may result in neonatal severe hyperparathyroidism (NSHPT). Parathyroid surgery is not indicated in FHH and does not lower plasma calcium unless total parathyroidectomy is performed, in...

  11. Calcium pump kinetics determined in single erythrocyte ghosts by microphotolysis and confocal imaging.

    OpenAIRE

    Kubitscheck, U; Pratsch, L; Passow, H; Peters, R.

    1995-01-01

    The activity of the plasma membrane calcium pump was measured in single cells. Human red blood cell ghosts were loaded with a fluorescent calcium indicator and either caged calcium and ATP (protocol A) or caged ATP and calcium (protocol B). In a suitably modified laser scanning microscope either calcium or ATP were released by a short UV light pulse. The time-dependent fluorescence intensity of the calcium indicator was then followed in single ghosts by repetitive confocal imaging. The fluore...

  12. A contribution towards the risk assessment of soils from the São Domingos Mine (Portugal): Chemical, microbial and ecotoxicological indicators

    International Nuclear Information System (INIS)

    This study is a contribution towards a risk assessment of the São Domingos Mine area (Portugal), integrating information from: soil physicochemical characteristics, pseudo-total and bioavailable trace elements (As, Cd, Cr, Cu, Ni, Pb and Zn), ecotoxicological evaluation, and microbial indicators. The bioassays using soil eluates (seed germination, luminescent inhibition of Vibrio fischeri and Daphnia magna immobilization) confirmed the soil toxicity categorization obtained with the bioassays using soil (plant growth tests, Eisenia fetida mortality and avoidance behaviour). However, the soil identified as the most toxic using bioassays, was different from the expected when considering the results from pseudo-total and effective bioavailable trace elements. Taking in consideration the observations, it is highly recommended to complement the results from environmental chemistry with results from bioassays, in order to provide a more complete and relevant information on the bioavailability of contaminants and to characterize the risk of contaminated soils. - Highlights: ► Impaired soil retention and habitat functions for all tested soils. ► Aquatic and terrestrial bioassays agreed in the soil toxicity categorization. ► Do results obtained by chemical methods really translate into “biological availability”? ► In multi-contaminated sites, risk estimation based only on chemical methods is inadequate. ► Bioassays provide a more realistic risk assessment of contaminated sites. - Bioassays provide a more complete and relevant information to characterize the risk of contaminated soils, and should be used to complement chemical results.

  13. The effect of crop sequences on soil microbial, chemical and physical indicators and its relationship with soybean sudden death syndrome (complex of Fusarium species)

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Brandan, C.; Arzeno, J. L.; Huidobro, J.; Conforto, C.; Grumberg, B.; Hilton, S.; Bending, G. D.; Meriles, J. M.; Vargas-Gil, S.

    2014-06-01

    The effect of crop sequences on soil quality indicators and its relationship with sudden death syndrome (SDS, a complex of Fusarium species) was evaluated by physical, chemical, biochemical and molecular techniques. Regarding physical aspects, soybean/maize and maize mono culture exhibited the highest stable aggregate level, with values 41% and 43% higher than in soybean mono culture, respectively, and 133% higher than in bean mono culture. Bulk density (BD) was higher in soybean monoculture, being 4% higher than in bean monoculture. The chemical parameters organic matter, total N, P, K, Mg, Ca, and water holding capacity also indicated that soybean/maize and maize monoculture improved soil quality. Fungal and bacterial community fingerprints generated using Terminal Restriction Fragment Length Polymorphism analysis of intergenic transcribed spacer regions of rRNA genes and 16S rRNA genes, respectively, indicated a clear separation between the rotations. Fatty acid profiles evaluated by FAME showed that bean monoculture had higher biomass of Gram (+) bacteria and stress indicators than maize monoculture, while the soybean/maize system showed a significant increase in total microbial biomass (total FAMEs content) in comparison with soybean and bean monoculture. The incidence of SDS (Fusarium crassistipitatum) was markedly higher (15%) under soybean monoculture than when soybean was grown in rotation with maize. In the present work, soil microbial properties were improved under soybean/maize relative to continuous soybean. The improvement of soil health was one of the main causes for the reduction of disease pressure and crop yield improvement due to the benefits that crop rotation produces for soil quality. (Author)

  14. The effect of crop sequences on soil microbial, chemical and physical indicators and its relationship with soybean sudden death syndrome (complex of Fusarium species

    Directory of Open Access Journals (Sweden)

    Carolina Perez-Brandan

    2013-12-01

    Full Text Available The effect of crop sequences on soil quality indicators and its relationship with sudden death syndrome (SDS, a complex of Fusarium species was evaluated by physical, chemical, biochemical and molecular techniques. Regarding physical aspects, soybean/maize and maize monoculture exhibited the highest stable aggregate level, with values 41% and 43% higher than in soybean monoculture, respectively, and 133% higher than in bean monoculture. Bulk density (BD was higher in soybean monoculture, being 4% higher than in bean monoculture. The chemical parameters organic matter, total N, P, K, Mg, Ca, and water holding capacity also indicated that soybean/maize and maize monoculture improved soil quality. Fungal and bacterial community fingerprints generated using Terminal Restriction Fragment Length Polymorphism analysis of intergenic transcribed spacer regions of rRNA genes and 16S rRNA genes, respectively, indicated a clear separation between the rotations. Fatty acid profiles evaluated by FAME showed that bean monoculture had higher biomass of Gram (+ bacteria and stress indicators than maize monoculture, while the soybean/maize system showed a significant increase in total microbial biomass (total FAMEs content in comparison with soybean and bean monoculture. The incidence of SDS (Fusarium crassistipitatum was markedly higher (15% under soybean monoculture than when soybean was grown in rotation with maize. In the present work, soil microbial properties were improved under soybean/maize relative to continuous soybean. The improvement of soil health was one of the main causes for the reduction of disease pressure and crop yield improvement due to the benefits that crop rotation produces for soil quality.

  15. 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 ...

  16. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

    Thomsen, Louiza Bohn; Jörntell, Henrik; Midtgaard, Jens

    2010-01-01

    appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than 1 s...... affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be...

  17. Composition and genesis of calcium deposits in atheroma plaques.

    Science.gov (United States)

    Lara, María Jesús; Ros, Eduardo; Sierra, Manuel; Dorronsoro, Carlos; Aguilar, José

    2014-05-01

    The composition of atheromatous plaque determines its progression toward rupture or thrombosis. Although its histopathological structure has been widely studied, little attention has been paid to its structural and chemical composition and even less to its mineral component. Thirty-three atheromatous plaques were obtained by carotid thromboendarterectomy. Three types of materials were observed under polarized light microscopy: apatite crystals in the form of glomeruli (dark with plane polarized illumination and greensh with cross-polarized illumination); fibrous-like cholesterol (uncolored or grayish with plane-polarized illumination); and amorphous organic material as brownish deposits. SEM-EDX analysis showed an abundance of phosphorus and calcium in sufficient quantities to form calcium phosphates, and appreciably reduced levels of sodium. X-ray diffraction results differentiated samples into three groups: group I with predominance of hydroxyapatite-type crystals, group II with crystalline material containing an amorphous component, and group III with wholly amorphous material. The most abundant mineral in atheromatous plaque is hydroxyapatite, on which crystals of cholesterol and lipid nuclei are deposited, stratifying the plaque into layers that reflect the different stages of its formation. The difference in calcium and sodium concentrations between arteries with and without atheromata may indicate an important relationship in the pathophysiological development of calcium deposits. PMID:24134634

  18. 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...

  19. Minocycline and Doxycycline, but not Other Tetracycline-Derived Compounds, Protect Liver Cells from Chemical Hypoxia and Ischemia/Reperfusion Injury by Inhibition of the Mitochondrial Calcium Uniporter

    OpenAIRE

    Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L.; Smith, Charles D.; Lemasters, John J.

    2013-01-01

    Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 μM of each tetracycline-derived compound 20 min prior to exposure to 500 μM iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were...

  20. Role of calcium in gravity perception of plant roots

    Science.gov (United States)

    Evans, Michael L.

    Calcium ions may play a key role in linking graviperception by the root cap to the asymmetric growth which occurs in the elongation zone of gravistimulated roots. Application of calcium-chelating agents to the root cap inhibits gravitropic curvature without affecting growth. Asymmetric application of calcium to one side of the root cap induces curvature toward the calcium source, and gravistimulation induces polar movement of applied 45Ca2+ across the root cap toward the lower side. The action of calcium may be linked to auxin movement in roots since 1) auxin transport inhibitors interfere both with gravitropic curvature and gravi-induced polar calcium movement and 2) asymmetric application of calcium enhances auxin movement across the elongation zone of gravistimulated roots. Indirect evidence indicates that the calcium-modulated regulator protein, calmodulin, may be involved in either the transport or action of calcium in the gravitropic response mechanism of roots.

  1. The use of chemical and isotopic data as indicators of the origin of waters and dissolved salts in the Bambui calcareous aquifer (Bahia-Brazil)

    International Nuclear Information System (INIS)

    Samples of 25 wells located in the Bambui limestone aquifer in the region of Irece - Bahia, have been analised for the isotopic ratio 18O/16O and the major chemical species Ca, Mg, Na, K, Cl, SO4 and bicarbonate. The oxygen-18 data have been found to range between -2,62/00(in a thousand) to -6,66/00(in a thousand) relative to the universal Standard Mean Ocean Water (SMOW) and are compared with the values of the precipitation in the localities of Jacobina and Lencois (meteorological stations nearby) and with the values of the groundwater in sedimentary basins in northeastern Brazil. The comparison suggests that aquifer system is recharged by precipitation originated in northeastern Brazil, instead of originating on coast of Bahia, east of the area. Furthermore, the waters in aquifer are not found homogenized, having widely varying 18O and chemical composition and being of different ages. The strong correlation between the observations Ca, Mg, Na, Cl and TDS (total dissolved solids) suggests an aerosol origin of salts, not excluding the hypothesis of dissolution of rock, which concentrations. The comparison of characteristic ratios Mg/Ca, SO4/Cl and (Cl-Na)/Cl, a Piper diagrama and a dendrogram established by cluster analysis, indicates that the wells may be separated in to two groups according to the isotopic or geochemical environment to which they belong. These groups may represent the differents sources of salt proposed, one being from the limestone, the other having come from aerosols. (Author)

  2. Characterization of mandarin (Citrus deliciosa Ten.) essential oil. Determination of volatiles, non-volatiles, physico-chemical indices and enantiomeric ratios.

    Science.gov (United States)

    Bonaccorsi, Ivana; Dugo, Paola; Trozzi, Alessandra; Cotroneo, Antonella; Dugo, Giovanni

    2009-11-01

    An investigation of 27 samples of mandarin essential oils (Citrus deliciosa Tenore), industrially produced in Sicily during the 2007-2008 season, was performed to determine the composition of the volatile fraction by GC/FID and GC/MS-LRI, the enantiomeric distribution of some monoterpene hydrocarbons and linalol by Es-GC, the non-volatile oxygen heterocyclic components by RP-HPLC/PDA and the physico-chemical indices (relative density, refractive index, optical rotation, residue on evaporation, and UV spectroscopic CD value). This study up-dates the information available in the literature on Sicilian mandarin (C. deliciosa Ten.) essential oils, and provides information on the composition and quality parameters for the evaluation of this product. PMID:19967998

  3. Study of the chemical environment of cerium in low silica calcium aluminosilicate glasses by extended X-ray absorption fine structure (EXAFS)

    International Nuclear Information System (INIS)

    Full text. Currently, great attention has been given to rare earth doped optical glasses. These elements by having the 4f shell partially filled exhibit a wealth of sharp fluorescent transitions representing almost every region of the visible and near-infrared portions of the electromagnetic spectrum, being of interest in photonics, when embedded in the glass matrix. In addition cerium oxide possess high hardness and stability to high temperatures, and it has been used in industry in different ways such as catalysts, fuel and solar cells, ultraviolet radiation filters, oxygen sensors and in the polishing of materials. In this context, cerium doped low silica calcium aluminosilicate (LSCA) glasses are considered good candidates for solid state laser active medium due to their good mechanical, optical and thermal properties. Recently it was shown that LSCA glasses doped with cerium oxide is a source of emitting white light, which is of technological applications interest. However it is known that increasing the dopant concentration in the glass matrix, an interaction of rare earth ions takes place leading to a closer proximity between the rare earth ions, and thus a reduction in their quantum efficiency. In this work, the local structure of Cerium in LSCA glasses was characterized by Extended X-Ray Absorption Fine Structure Spectroscopy (EXAFS). The EXAFS and XANES measurements were performed in the Ce LIII-edge at the XAS beam line of LNLS facility (Campinas, Brazil) at room temperature. Structural parameters, coordination numbers (N), interatomic distance (R) and degree of disorder (σ2) were obtained from least squares fitting

  4. Groundwater quality impacts from the land application of treated municipal wastewater in a large karstic spring basin: Chemical and microbiological indicators

    International Nuclear Information System (INIS)

    Geochemical and microbiological techniques were used to assess water-quality impacts from the land application of treated municipal wastewater in the karstic Wakulla Springs basin in northern Florida. Nitrate-N concentrations have increased from about 0.2 to as high as 1.1 mg/L (milligrams per liter) during the past 30 years in Wakulla Springs, a regional discharge point for groundwater (mean flow about 11.3 m3/s) from the Upper Floridan aquifer (UFA). A major source of nitrate to the UFA is the approximately 64 million L/d (liters per day) of treated municipal wastewater applied at a 774 ha (hectare) sprayfield farming operation. About 260 chemical and microbiological indicators were analyzed in water samples from the sprayfield effluent reservoir, wells upgradient from the sprayfield, and from 21 downgradient wells and springs to assess the movement of contaminants into the UFA. Concentrations of nitrate-N, boron, chloride, were elevated in water samples from the sprayfield effluent reservoir and in monitoring wells at the sprayfield boundary. Mixing of sprayfield effluent water was indicated by a systematic decrease in concentrations of these constituents with distance downgradient from the sprayfield, with about a 10-fold dilution at Wakulla Springs, about 15 km (kilometers) downgradient from the sprayfield. Groundwater with elevated chloride and boron concentrations in wells downgradient from the sprayfield and in Wakulla Springs had similar nitrate isotopic signatures, whereas the nitrate isotopic composition of water from other sites was consistent with inorganic fertilizers or denitrification. The sprayfield operation was highly effective in removing most studied organic wastewater and pharmaceutical compounds and microbial indicators. Carbamazepine (an anti-convulsant drug) was the only pharmaceutical compound detected in groundwater from two sprayfield monitoring wells (1-2 ppt). One other detection of carbamazepine was found in a distant well water

  5. 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.

  6. Protein Adsorption of Calcium Phosphate Ceramics in vitro

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In order to provide valuable information for the design of new calcium phosphate bone repair materials, bone tissue engineering scaffold materials, and other clinical application, the interaction between calcium phosphate materials and proteins were investigated. The adsorption of the calcium phosphate ceramic to the protein was investigated by using FT- IR, XPS, SEM, and SDS- PAGE. As the results shown, the proteins were strongly adsorbed by the CPC, and a shift of the feature peak of the protein and also a chemical shift in the Ca2p and O1s bind energy of CPC was observed. This indicated that the acidic amino-group and alkaline amino- residue on the proteins' surface bonded to the Ca2 + in the β- TCP crystal by ionic bond and the proteins' alkaline amino groups to the oxygen in PO3-4 by hydrogen bond and electrostatic attraction. The adsorption mechanism of the protein in the CPC can be described as three ndsorption layers: irreversible chemical adsorption layer, physical adsorption layer and biomineralized adsorption layer.

  7. Transfected parvalbumin alters calcium homeostasis in teratocarcinoma PCC7 cells

    DEFF Research Database (Denmark)

    Müller, B K; Kabos, P; Belhage, B;

    1996-01-01

    transfected. Parvalbumin-transfected and mock-transfected cells were loaded with the calcium indicator fura-2 and were exposed, in the same dish, to different concentrations of the calcium ionophore A23187 or to KCI. The results show that parvalbumin-transfected PCC7 cells had much better calcium buffering...

  8. Stochastic models of intracellular calcium signals

    International Nuclear Information System (INIS)

    Cellular signaling operates in a noisy environment shaped by low molecular concentrations and cellular heterogeneity. For calcium release through intracellular channels–one of the most important cellular signaling mechanisms–feedback by liberated calcium endows fluctuations with critical functions in signal generation and formation. In this review it is first described, under which general conditions the environment makes stochasticity relevant, and which conditions allow approximating or deterministic equations. This analysis provides a framework, in which one can deduce an efficient hybrid description combining stochastic and deterministic evolution laws. Within the hybrid approach, Markov chains model gating of channels, while the concentrations of calcium and calcium binding molecules (buffers) are described by reaction–diffusion equations. The article further focuses on the spatial representation of subcellular calcium domains related to intracellular calcium channels. It presents analysis for single channels and clusters of channels and reviews the effects of buffers on the calcium release. For clustered channels, we discuss the application and validity of coarse-graining as well as approaches based on continuous gating variables (Fokker–Planck and chemical Langevin equations). Comparison with recent experiments substantiates the stochastic and spatial approach, identifies minimal requirements for a realistic modeling, and facilitates an understanding of collective channel behavior. At the end of the review, implications of stochastic and local modeling for the generation and properties of cell-wide release and the integration of calcium dynamics into cellular signaling models are discussed

  9. Stochastic models of intracellular calcium signals

    Energy Technology Data Exchange (ETDEWEB)

    Rüdiger, Sten, E-mail: sten.ruediger@physik.hu-berlin.de

    2014-01-10

    Cellular signaling operates in a noisy environment shaped by low molecular concentrations and cellular heterogeneity. For calcium release through intracellular channels–one of the most important cellular signaling mechanisms–feedback by liberated calcium endows fluctuations with critical functions in signal generation and formation. In this review it is first described, under which general conditions the environment makes stochasticity relevant, and which conditions allow approximating or deterministic equations. This analysis provides a framework, in which one can deduce an efficient hybrid description combining stochastic and deterministic evolution laws. Within the hybrid approach, Markov chains model gating of channels, while the concentrations of calcium and calcium binding molecules (buffers) are described by reaction–diffusion equations. The article further focuses on the spatial representation of subcellular calcium domains related to intracellular calcium channels. It presents analysis for single channels and clusters of channels and reviews the effects of buffers on the calcium release. For clustered channels, we discuss the application and validity of coarse-graining as well as approaches based on continuous gating variables (Fokker–Planck and chemical Langevin equations). Comparison with recent experiments substantiates the stochastic and spatial approach, identifies minimal requirements for a realistic modeling, and facilitates an understanding of collective channel behavior. At the end of the review, implications of stochastic and local modeling for the generation and properties of cell-wide release and the integration of calcium dynamics into cellular signaling models are discussed.

  10. Coupling Effect of Ion Channel Clusters on Calcium Signalling

    International Nuclear Information System (INIS)

    Based on a modified intracellular Ca2+ model involving diffusive coupling of two calcium ion channel clusters, the effects of coupling on calcium signalling are numerically investigated. The simulation results indicate that the diffusive coupling of clusters together with internal noise determine the calcium dynamics of single cluster, and for either homogeneous or heterogeneous coupled clusters, the synchronization of clusters, which is important to calcium signalling, is enhanced by the coupling effect

  11. Coupling Effect of Ion Channel Clusters on Calcium Signalling

    Institute of Scientific and Technical Information of China (English)

    TANG Jun; JIA Ya; YI Ming; MA Jun; YU Guang

    2008-01-01

    @@ Based on a modified intracellular Ca2+ model involving diffusive coupling of two calcium ion channel clusters,the effects of coupling on calcium signalling are numerically investigated.The simulation results indicate that the diffusive coupling of clusters together with internal noise determine the calcium dynamics of single cluster,and for either homogeneous or heterogeneous coupled clusters,the synchronization of clusters,which is important to calcium signalling,is enhanced by the coupling effect.

  12. Chemical stabilization and solidification of heavy metal contaminated dredged sludge from Hamburg harbour

    OpenAIRE

    Khorasani, Reza; Calmano, Wolfgang; Gottschalk, F.

    1988-01-01

    Contaminated sludges from Hamburg harbour have been stabilized by means of lime, calcium hydroxide, calcium carbonate, gypsum, trass, waste kiln dust, cement, coal fly ash, and red mud. Analysis of the solidification products by polarization microscope, electron microscope, x-ray diffraction, electron microprobe, and PIXE microprobe indicate that new minerals have been formed which stabilize the material and change, as confirmed by chemical extraction methods and leaching tests, the phase spe...

  13. A COMPARATIVE PHARMACEUTICAL STUDY ON CA (ION) SUBSTANCES OF VARIOUS AYURVEDIC CALCIUM COMPOUNDS

    OpenAIRE

    Saini Vinod; Shah Deepti; Mangal Gopesh; Garg Gunjan; Swarnkar Divya Prakash

    2013-01-01

    Various Ayurvedic calcium compounds, which are among the sudha vargiya dravya, are a rich source of calcium. These calcium compounds have wide range of therapeutic application. In chemical composition these compounds are same hence the present study was aimed to identify the rich percentage of calcium (as CaO) in these Bhasmas. Preparation of Ayurvedic calcium compounds i.e. praval bhasma, shankha bhasma, shukti bhasma, varatika bhasma, godanti bhasma and kukkutandatvak bhasma was done by sub...

  14. 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 ...

  15. 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 ...

  16. 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 ...

  17. 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 ...

  18. Effect of calcium/sodium ion exchange on the osmotic properties and structure of polyelectrolyte gels.

    Science.gov (United States)

    Horkay, Ferenc; Basser, Peter J; Hecht, Anne-Marie; Geissler, Erik

    2015-12-01

    We discuss the main findings of a long-term research program exploring the consequences of sodium/calcium ion exchange on the macroscopic osmotic and elastic properties, and the microscopic structure of representative synthetic polyelectrolyte (sodium polyacrylate, (polyacrylic acid)) and biopolymer gels (DNA). A common feature of these gels is that above a threshold calcium ion concentration, they exhibit a reversible volume phase transition. At the macroscopic level, the concentration dependence of the osmotic pressure shows that calcium ions influence primarily the third-order interaction term in the Flory-Huggins model of polymer solutions. Mechanical tests reveal that the elastic modulus is practically unaffected by the presence of calcium ions, indicating that ion bridging does not create permanent cross-links. At the microscopic level, small-angle neutron scattering shows that polyacrylic acid and DNA gels exhibit qualitatively similar structural features in spite of important differences (e.g. chain flexibility and chemical composition) between the two polymers. The main effect of calcium ions is that the neutron scattering intensity increases due to the decrease in the osmotic modulus. At the level of the counterion cloud around dissolved macroions, anomalous small-angle X-ray scattering measurements made on DNA indicate that divalent ions form a cylindrical sheath enveloping the chain, but they are not localized. Small-angle neutron scattering and small-angle X-ray scattering provide complementary information on the structure and interactions in polymer solutions and gels. PMID:26614803

  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. Localization and pharmacological characterization of voltage dependent calcium channels in cultured neocortical neurons

    DEFF Research Database (Denmark)

    Timmermann, D B; Lund, Trine Meldgaard; Belhage, B;

    2001-01-01

    The physiological significance and subcellular distribution of voltage dependent calcium channels was defined using calcium channel blockers to inhibit potassium induced rises in cytosolic calcium concentration in cultured mouse neocortical neurons. The cytosolic calcium concentration was measured...... using the fluorescent calcium chelator fura-2. The types of calcium channels present at the synaptic terminal were determined by the inhibitory action of calcium channel blockers on potassium-induced [3H]GABA release in the same cell preparation. L-, N-, P-, Q- and R-/T-type voltage dependent calcium...... most important voltage dependent calcium channel in all parts of the neuron. After treatment with thapsigargin the increase in cytosolic calcium was halved, indicating that calcium release from thapsigargin sensitive intracellular calcium stores is an important component of the potassium induced rise...

  2. [Discovering L-type calcium channels inhibitors of antihypertensive drugs based on drug repositioning].

    Science.gov (United States)

    Liang, Ying-xi; He, Yu-su; Jiang, Lu-di; Yue, Qiao-xin; Cui, Shuai; Bin, Li; Ye, Xiao-tong; Zhang, Xiao-hua; Zhang, Yang-ling

    2015-09-01

    This study was amid to construct the pharmacophore model of L-type calcium channel antagonist in the application of screening Drugbank and TCMD. This paper repositions the approved drugs resulting from virtual screening and discusses the relocation-based drug discovery methods, screening antihypertensive drugs with L-type calcium channel function from TCMD. Qualitative hypotheses wre generated by HipHop separately on the basis of 12 compounds with antagonistic action on L-type calcium channel expressed in rabbit cardiac muscle. Datebase searching method was used to evaluate the generated hypotheses. The optimum hypothesis was used to search Drugbank and TCMD. This paper repositions the approved drugs and evaluates the antihypertensive effect of the chemical constituent of traditional Chinese medicine resulting from virtual screening by the matching score and literature. The results showed that optimum qualitative hypothesis is with six features, which were two hydrogen-bond acceptors, four hydrophobic groups, and the CAI value of 2.78. Screening Drugbank achieves 93 approved drugs. Screening TCMD achieves 285 chemical constituents of traditional Chinese medicine. It was concluded that the hypothesis is reliable and can be used to screen datebase. The approved drugs resulting from virtual screening, such as pravastatin, are potentially L-type calcium channels inhibitors. The chemical constituents of traditional Chinese medicine, such as Arctigenin III and Arctigenin are potentially antihypertensive drugs. It indicates that Drug Repositioning based on hypothesis is possible. PMID:26983215

  3. 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

  4. 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

  5. Intercomparison 9711. pH, conductivity, alkalinity, nitrate + nitrite, chloride, sulfate, calcium, magnesium, sodium, potassium, total aluminium, reactive and non-labile aluminium, dissolved organic carbon, and chemical oxygen demand

    Energy Technology Data Exchange (ETDEWEB)

    Hovind, Haavard

    1997-09-22

    The work described in this report was a part of an international cooperative programme for assessment and monitoring of acidification of rivers and lakes. Two sample sets were prepared for intercomparison, one for determination of the major ions, the other for determination of aluminium fractions and unspecified organic matter. The samples were sent to 50 laboratories and 47 laboratories from 22 countries submitted results. Good agreement was found for chloride, sulfate, calcium, magnesium, sodium and the unspecific organic compounds, dissolved organic carbon and chemical oxygen demand, more than 80% being evaluated as acceptable for these analytic variables. The results for nitrate + nitrite and aluminium species did not agree well, probably because different methods were used to determine the aluminium species. On the whole, 78% of the results were within the general target accuracy of plus or minus 20%. Laboratories with results outside this accuracy should improve their methods if they want to analyse low-concentration samples. To improve the compatibility of the analytical results for aluminium fractions, it seems necessary to normalize the analytical methods and determination techniques used for these determinations. A total error of plus minus 0.2 pH units seems to be a reasonable assessment of the accuracy for pH measurements when weakly acid or neutral water samples not in CO{sub 2} equilibrium are analyzed. 7 refs., 1 fig., 34 tabs.

  6. Chemical and morphological characteristics of solid metal-bearing phases deposited in snow and stream sediment as indicators of their origin.

    Science.gov (United States)

    Miler, Miloš; Gosar, Mateja

    2015-02-01

    Detailed scanning electron microscopy/energy dispersive spectroscopy of metal-bearing particles in snow deposits and stream sediment from a steelworks area was performed. Identified metal-bearing phases were apportioned according to their chemical and morphological characteristics to anthropogenic phases and secondary weathering products. Anthropogenic metal-bearing phases are the most abundant in both media and are represented by various irregular ferrous oxides, ferrous alloys, spherical ferrous oxides, and ferrous silicates with variable contents of Cr, Mn, Ni, V, W, and Mo. Secondary weathering products are Al silicates, Fe oxy-hydroxides, and Fe oxy-hydroxy sulfates with minor contents of transition metals, resulting from weathering of anthropogenic phases and Pb-Zn ore minerals from a closed Pb-Zn mine located upstream from the study area. Comparison of anthropogenic metal-bearing phases in both media showed agreement in their compositions and morphologies and indicated their sources are high-temperature processes in steel production. It also showed that spherical metal-bearing phases were transported by the same transport medium, which is the atmosphere, while other phases were transported into stream sediment mostly by other pathways, such as precipitation runoff over contaminated surfaces. PMID:25233920

  7. 化学物相分析法测定瓮福磷尾矿中钙镁磷元素形态含量%Determination of Occurrence States of Calcium, Magnesium, Phosphorus in Wengfu Phosphorus Tailings by Chemical Phase Analysis

    Institute of Scientific and Technical Information of China (English)

    金绍祥

    2011-01-01

    用化学物相分析法测定瓮福磷尾矿中钙、镁、磷元素形态含量.结果表明,磷尾矿中钙主要以白云石的形式赋存,并有少量以方解石、磷酸盐形式存在;镁主要以白云石的形式赋存,并有少量以磷酸盐、硅酸盐形式存在;磷主要以磷灰石的形式赋存,并有少量以铁氧化物、独居石、磷钇矿形式存在.各元素形态加标回收率为97.6%~107.2%,相对标准偏差(RSD,n=12)为0.77%~4.85%.各元素形态分析结果表现出较好的稳定性,表明采用化学物相分析法测定瓮福磷尾矿中钙、镁、磷元素形态含量结果准确可靠.%The contents of calcium, magnesium and phosphorus species in Wengfu Phosphorus Tailings were determined by chemical phase analysis method. The results showed that calcium existed mainly as dolomite with a few as calcite and phosphate , magnesium existed mainly as dolomite with a few as phosphate and silicate and phosphorus existed mainly as phosphate with a few as iron oxides, monazite and xenotime. Standard recoveries for all species of the elements were 97.6% - 107. 2% with precision of 0. 77% -4. 85% RSD (n = 12). Speciation analysis results presented a good stability, which indicated that the analytical results of ccurrence states of Ca, Mg and P in Wengfu Phosphorus Tailings by chemical phase analysis method were accurate and reliable.

  8. 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.

  9. Role of Calcium Hydroxide in Endodontics: A Review

    OpenAIRE

    Arun A; Sangameshwar Sajjanshetty; Deepak Jain; Saujanya KP; Mohammed Mustafa; Laxmi Uppin; Mahnoor Kadri

    2012-01-01

    Calcium hydroxide is a multipurpose agent, and there have been an increasing number of indications for its use in endodontics. Some of its indications include inter-appointment intracanal medicaments, endodontic sealers, pulp capping agents, apexification, pulpotomy and weeping canals. The purpose of this article is to review the properties, advantages, disadvantages and various indications for the use of calcium hydroxide in endodontics.

  10. Assessment of the relationship between selected cardiovascular risk factors and the indices of intima-media thickness and coronary artery calcium score in various stages of chronic kidney disease.

    Science.gov (United States)

    Szarejko-Paradowska, Anna; Gluba-Brzózka, Anna; Pietruszyński, Robert; Rysz, Jacek

    2015-12-01

    Renal diseases pose a growing epidemiological and health problem worldwide. Cardiovascular diseases are the leading cause of deaths among patients with chronic kidney disease. Increased risk of atherosclerosis in these patients results from the occurrence of traditional and non-traditional risk factors. The aim of this study was to assess the relationship between selected risk factors for cardiovascular diseases (age, sex, dyslipidemia, hypertension, etc.), intima-media thickness and coronary artery calcium score in patients with chronic kidney disease stages 2, 3 and 4. This study included 60 patients with chronic kidney disease divided into 3 groups on the basis of disease stage and control group consisting of 20 individuals without diagnosed chronic kidney disease and cardiovascular diseases. Blood analysis and blood pressure measurements were taken. All patients underwent carotid artery ultrasound with the assessment of the intima-media thickness, and heart CT scan in order to assess the index of coronary artery calcification. Logistic regression analysis revealed statistically significant correlation between blood vessels calcification and age--the increase in age by 1 year was associated with the increase in the risk of coronary artery calcification by 6.7 %. The increase in IMT by about 0.1 mm raises the risk of calcification by about 2 %. Second logistic regression model revealed that one-year increase in age was associated with an increase in the risk of intima-media thickening by 6.5 %. Occurrence of hypertension was associated with a ninefold increase in intima-media thickening risk in comparison with patients with normal blood pressure. To sum up, age and hypertension were associated with the growth of IMT in CKD patients, while age and exposure to tobacco smoke were associated with the increase in coronary artery calcium score. The relationship between thickening of IMT and the increase in calcification index in patients was also observed in study

  11. Phases of Environmental Evolution Indicated by Primary Chemical Elements and Paleontological Records in the Upper Pleistocene-Holocene Series for the Salawusu River Valley, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Studies of lithology, sedimentary facies and the distribution regularity of SiO2 and Al2O3 contents and Al2O3/SiO2 ratio allow us to divide the Upper Pleistocene-Holocene Series represented by the Milanggouwan section in China's Salawusu River valley into six segments: MGS1, MGS2, MGS3,MGS4, MGS5 and MGS6. The boundary ages for MGS1 (the Dishaogouwan and Dagouwan Formations), MGS2 (the upper Chengchuan Formation), MGS3 (the middle Chengchuan Formation),MGS4 (the lower Chengchuan Formation), MGS5 (most strata of the Salawusu Formation) and MGS6 (the bottom of the Salawusu Formation and the top of the Lishi Formation) correspond to those of MIS1, MIS2, MIS3, MIS4, MIS5 and MIS6, respectively, from deep sea sediments or continental glaciers. MGS5 can be subdivided into five subsegments (MGS5a, MGS5b, MGS5c,MGS5d and MGS5e) and the boundary ages of these subsegments correspond to those of MIS5a,MIS5b, MIS5c, MIS5d and MIS5e, respectively. Based on the paleoenvironment and paleoecology indicated by the primary chemical elements, fossil vertebrates, mollusks and pollen grains, we hypothesize that MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6 and the subsegments of MGS5 match the corresponding stages for oxygen isotopes in the deep sea sediments and continental glaciers,and the substages of MIS5 in terms of climatic characters, further explaining the phenomena that determined the formation of the late Quaternary strata and the paleontology of the Salawusu River valley. These phenomena relate to fluctuations in the global climate (and particularly in the East Asian monsoon) during the glacial and interglacial periods.

  12. Modelling response patterns of physico-chemical indicators during high-rate composting of green waste for suppression of Pythium ultimum.

    Science.gov (United States)

    St Martin, Chaney C G; Bekele, Isaac; Eudoxie, Gaius D; Bristol, Dexter; Brathwaite, Richard A I; Campo, Kenia-Rosa

    2014-01-01

    High-rate composting studies on green waste, i.e. banana leaves (BL) and lawn clippings (LC), were conducted in 0.25-m3 rotary barrel composters to evaluate and model changes in key physico-chemical parameters during composting. Time to compost maturity and antagonistic effects and relationships of composts against Pythium ultimum were also investigated. Higher temperatures were achieved in LC compost (LCC), which did not translate to higher total organic carbon (TOC) loss but resulted in lower carbon to nitrogen ratio (C:N) and a more mature compost. With the exception of electrical conductivity (EC), net decreases were observed in pH, TOC and C:N across compost types. Total Kjeldahl nitrogen (TKN) showed a net increase in LCC and a net decrease in BLC. With the exception of TOC and pH, the results showed that compost type and time had a significant effect on the respective TKN, EC and C:N models. Compost temperature and TOC were best described by the critical exponential and rectangular hyperbola functions, respectively. Whereas TKN, C:N and pH were described using double Fourier functions and EC using Fourier functions. Composts achieved maturity within 19 days and significantly inhibited the growth of P. ultimum. Bacterial population was positively related to growth inhibition (GI) across compost types, whereas total microbial population had a positive relationship with GI in LCC. Evidence suggests that multiple groups of microorganisms contributed to GI through antibiosis and competition for resources. Composts were determined to be suitable for use as components of plant growth substrates based on compost maturity indices. PMID:24645438

  13. 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...

  14. On the composition and atomic arrangement of calcium-deficient hydroxyapatite: An ab-initio analysis

    International Nuclear Information System (INIS)

    A systematic study of defect constellations in calcium-deficient hydroxyapatite is reported. Along this line, we explore different arrangements for charge compensation, including cationic vacancies and substitutional defects. The overall defect constellation is governed by both the different proton affinity of the anions or energy costs related to vacancy formation and minimization of the Coulomb energy which implies small distances of the anionic and cationic defects. Depending on the type of the calcium-deficient site, this gives rise to two specific defect arrangements. Among these, the calcium ions forming triangles which embed the OH- ions of hydroxyapatite are most likely to be deficient. The resulting charge is compensated by protonation of the OH- ion within the deficient calcium-triangle and protonation of a PO43- ion in the nearest neighbourhood of the vacant calcium site. The strong energetic favouring of such constellations indicates that the commonly used chemical formulae Ca10-x(HPO4)x(PO4)6-x(OH)2-x(H2O)x (02O defect and a HPO42- defect adjacent to the deficient Ca site. The preferential defect arrangement reflects a compromise of local charge compensation, different proton affinities of the anions and hydrogen bonding

  15. Calcium Intake in Elderly Australian Women Is Inadequate

    Directory of Open Access Journals (Sweden)

    Colin W. Binns

    2010-09-01

    Full Text Available The role of calcium in the prevention of bone loss in later life has been well established but little data exist on the adequacy of calcium intakes in elderly Australian women. The aim of this study was to compare the dietary intake including calcium of elderly Australian women with the Australian dietary recommendation, and to investigate the prevalence of calcium supplement use in this population. Community-dwelling women aged 70–80 years were randomly recruited using the Electoral Roll for a 2-year protein intervention study in Western Australia. Dietary intake was assessed at baseline by a 3-day weighed food record and analysed for energy, calcium and other nutrients. A total of 218 women were included in the analysis. Mean energy intake was 7,140 ± 1,518 kJ/day and protein provided 19 ± 4% of energy. Mean dietary calcium intake was 852 ± 298 mg/day, which is below Australian recommendations. Less than one quarter of women reported taking calcium supplements and only 3% reported taking vitamin D supplements. Calcium supplements by average provided calcium 122 ± 427 mg/day and when this was taken into account, total calcium intake increased to 955 ± 504 mg/day, which remained 13% lower than the Estimated Average Requirement (EAR, 1,100 mg/day for women of this age group. The women taking calcium supplements had a higher calcium intake (1501 ± 573 mg compared with the women on diet alone (813 ± 347 mg. The results of this study indicate that the majority of elderly women were not meeting their calcium requirements from diet alone. In order to achieve the recommended dietary calcium intake, better strategies for promoting increased calcium, from both diet and calcium supplements appears to be needed.

  16. Sterilization of health care products - Chemical indicators - Part 4: Class 2 indicators as an alternative to the Bowie and Dick-type test for detection of steam penetration. 2. ed.

    International Nuclear Information System (INIS)

    This part of ISO 11140 specifies the performance of the indicator system in combination with the test load with which it is intended to be used. The test load may be presented with the indicator system already incorporated and intended for single use, or it may be intended for multiple use with a new indicator system to be inserted prior to each use. The indicator for which the performance is specified in this part of ISO 11140 is intended to indicate when steam penetration has been inadequate. The performance of the indicator specified in this part of ISO 11140 should be equivalent, but not necessarily identical, to the performance obtained in the Bowie and Dick-type test as described in ISO 11140-3. Equivalence should be regarded as providing a similar response to steam penetration with any differences being predictable and such that the necessary level of assurance of satisfactory steam penetration is provided. An indicator meeting this specification is not intended to identify which of the potential causes of poor steam penetration was responsible for the failure indicated by the test. This part of ISO 11140 specifies the performance for a Class 2 indicator to be used as an alternative to the Bowie and Dick-type test for steam sterilizers for wrapped health care goods (instruments, etc., and porous loads). The Bowie and Dick-type test is used for routine testing of steam sterilizers and validation of steam sterilization processes. An indicator complying with this part of ISO 11140 incorporates a specified material which is used as a test load. This test load may, or may not, be re-usable. This part of ISO 11140 does not specify requirements for the test load, but specifies the performance of the indicator in combination with the test load with which it is intended to be used. The indicator specified in this part of ISO 11140 is intended to identify poor steam penetration but does not necessarily indicate the cause of this poor steam penetration. This part of

  17. 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...

  18. 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

  19. Towards validating use of self reported health (SRH) for community-based studies: Impact of environmental chemicals, sociodemographic variables, depression, and clinical indicators of health and nutrition

    Science.gov (United States)

    Environmental health impact assessment (HIA) studies, should consider social, behavioral, nutritional, dietary, environmental exposure and health risk factors at both the individual and community levels. Chemicals measured in blood or urine are often evaluated in relation to one ...

  20. 21 CFR 184.1212 - Calcium pantothenate.

    Science.gov (United States)

    2010-04-01

    ... the B complex. Only the D-isomer of pantothenic acid has vitamin activity, although both the D-isomer...-propionaldehyde and pantolactone. (b) Calcium pantothenate meets the specifications of the Food Chemicals Codex..._regulations/ibr_locations.html. (c) In accordance with § 184.1(b)(1), the ingredient is used in food with...

  1. 21 CFR 184.1195 - Calcium citrate.

    Science.gov (United States)

    2010-04-01

    ... Food Chemicals Codex, 3d ed. (1981), pp. 49 and 50, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from the National Academy Press, 2101... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium citrate. 184.1195 Section 184.1195 Food...

  2. 21 CFR 184.1191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... process”. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 46... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium carbonate. 184.1191 Section 184.1191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  3. 21 CFR 184.1229 - Calcium stearate.

    Science.gov (United States)

    2010-04-01

    ... ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 64, which is incorporated... Codex are available from the National Academy Press, 2101 Constitution Ave. NW., Washington, DC 20418... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium stearate. 184.1229 Section 184.1229...

  4. 21 CFR 184.1210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

    ... specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 55, which is incorporated by reference. Copies are... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium oxide. 184.1210 Section 184.1210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...

  5. A Multiplexed Fluorescent Calcium and NFAT Reporter Gene Assay to Identify GPCR Agonists

    OpenAIRE

    Sheth, Heeral; Gorey, Colleen; Roush, Nicole; Smallman, Shelly; Collantes, Elizabeth; Santoro, Maxine; Olson, Barbara; Fitzgerald, Laura; Paul H. Lee; Shen, Xiqiang John

    2013-01-01

    Intracellular calcium response and resulting calcium signaling to an agonist-GPCR interaction are important for the measurement of compound activity in the GPCR drug development. The increase in cytosol calcium concentration can be measured by the fluorescent calcium indicator dye such as Fluo-4 in a quick assay (in 3-5 minutes) using the fluorescence imaging plate reader. The calcium signaling through the transcription factors such as NFAT that induces gene expression can be measured by the ...

  6. 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...

  7. 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.

  8. Paclitaxel Induces Apoptosis in Breast Cancer Cells through Different Calcium—Regulating Mechanisms Depending on External Calcium Conditions

    Directory of Open Access Journals (Sweden)

    Zhi Pan

    2014-02-01

    Full Text Available Previously, we reported that endoplasmic reticulum calcium stores were a direct target for paclitaxel initiation of apoptosis. Furthermore, the actions of paclitaxel attenuated Bcl-2 resistance to apoptosis through endoplasmic reticulum-mediated calcium release. To better understand the calcium-regulated mechanisms of paclitaxel-induced apoptosis in breast cancer cells, we investigated the role of extracellular calcium, specifically; whether influx of extracellular calcium contributed to and/or was necessary for paclitaxel-induced apoptosis. Our results demonstrated that paclitaxel induced extracellular calcium influx. This mobilization of extracellular calcium contributed to subsequent cytosolic calcium elevation differently, depending on dosage. Under normal extracellular calcium conditions, high dose paclitaxel induced apoptosis-promoting calcium influx, which did not occur in calcium-free conditions. In the absence of extracellular calcium an “Enhanced Calcium Efflux” mechanism in which high dose paclitaxel stimulated calcium efflux immediately, leading to dramatic cytosolic calcium decrease, was observed. In the absence of extracellular calcium, high dose paclitaxel’s stimulatory effects on capacitative calcium entry and apoptosis could not be completely restored. Thus, normal extracellular calcium concentrations are critical for high dose paclitaxel-induced apoptosis. In contrast, low dose paclitaxel mirrored controls, indicating that it occurs independent of extracellular calcium. Thus, extracellular calcium conditions only affect efficacy of high dose paclitaxel-induced apoptosis.

  9. Recording of calcium transient and analysis of calcium removal mechanisms in cardiac myocytes from rats and ground squirrels

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    With confocal microscopy, we recorded calcium transients and analyzed calcium removal rate at different temperatures in cardiac myocytes from the rat, a non-hibernator, and the ground squirrel, a hibernator. The results showed a remarkable increase of the diastolic level of calcium transients in the rat but no detectable change in the ground squirrel. Calcium transient of the ground squirrel, compared with that of the rat at the same temperature, had a shorter duration and showed a faster calcium removal. As indicated by the pharmacological effect of cyclopiazonic acid, calcium uptake by sarcoplasmic reticulum (SR) was the major mechanism of calcium removal, and was faster in the ground squirrel than in the rat. Our results confirmed the essential role of SR in hypothermia-tolerant adaptation, and negated the importance of Na-Ca exchange. We postulated the possibility to improve hypothermia-tolerance of the cardiac tissue of non-hibernating mammals.

  10. Effect of CuO on the Formation Mechanism of Calcium Sulphoaluminate

    Institute of Scientific and Technical Information of China (English)

    MA Suhua; SHEN Xiaohong; HUANG Yeping; ZHONG Baiqian

    2008-01-01

    Calcium sulphoaluminate was prepared with chemical reagents in this paper.The formation mechanism of calcium sulphoaluminate and effect of CuO on the formation mechanism of calcium sulphoaluminate were investigated by the chemical analysis,X-ray diffraction(XRD),and differential scanning calorimetry(DSC).The results show that there are three ways in the formation of calcium sulphoaluminate.CuO can promote the decomposition of calcium carbonate and decrease the formation temperature of calcium sulphoaluminate(C4A3S).When the burning temperature is below 1000℃,the addition of CuO can promote the formation of calcium sulphoaluminate,while CuO can not favor the formation of calcium sulphoaluminate above 1000℃.

  11. Adsorption of Pb(II) present in aqueous solution on calcium, strontium and barium hydroxy apatites

    International Nuclear Information System (INIS)

    Calcium, strontium and barium hydroxy apatites were successfully synthesized by chemical precipitation method, the obtained powders were characterized by the techniques of X-ray diffraction (XRD), scanning electron microscopy (Sem), semi-quantitative elemental analysis (EDS), infrared spectroscopy (IR), and N2 physisorption studies, complementary to these analytical techniques, was determined the surface fractal dimension (Df), and the amount of surface active sites of the materials, in order to know application as ceramic for water remediation. The ability of Pb(II) ion adsorption present in aqueous solution on the hydroxy apatites synthesized by batch type experiments was studied as a function of contact time, concentration of the adsorbate and temperature. The maximum lead adsorption efficiencies obtained were 0.31, 0.32 and 0.26 mg/g for calcium, strontium and barium hydroxy apatites respectively, achieved an equilibrium time of 20 minutes in the three solid-liquid systems studied. Experimental data were adequately adjusted at the adsorption kinetic model pseudo-second order, for the three cases. Moreover, experimental data of the strontium and calcium hydroxy apatites were adjusted to the Langmuir adsorption isotherm, indicating that the adsorption was through a monolayer, whereas barium hydroxyapatite was adjusted to the Freundlich adsorption isotherm, indicating a multilayer adsorption. The thermodynamic parameters obtained during adsorption studies as a function of temperature showed physisorption, exothermic and spontaneous processes respectively. The results showed that the calcium hydroxyapatite, strontium and barium are an alternative for the Pb(II) ion adsorption present in wastewaters. (Author)

  12. 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...

  13. Phosphocitrate inhibits mitochondrial and cytosolic accumulation of calcium in kidney cells in vivo.

    OpenAIRE

    Tew, W. P.; Malis, C D; Howard, J. E.; Lehninger, A L

    1981-01-01

    Synthetic 3-phosphocitrate, an extremely potent inhibitor of calcium phosphate crystallization as determined in a nonbiological physical-chemical assay, has many similarities to a mitochondrial factor that inhibits crystallization of nondiffracting amorphous calcium phosphate. In order to determine whether phosphocitrate can prevent uptake and crystallization of calcium phosphate in mitochondria in vivo, it was administered intraperitoneally to animals given large daily doses of calcium gluco...

  14. 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...

  15. An efficient calcium phosphate nanoparticle-based nonviral vector for gene delivery

    Directory of Open Access Journals (Sweden)

    Liu YC

    2011-04-01

    Full Text Available Yachun Liu1,2,*, Tao Wang1,*, Fangli He1,*, Qian Liu1,*, Dexi Zhang2, Shuanglin Xiang1, Shengpei Su2, Jian Zhang11Key Laboratory of Protein Chemistry and Developmental Biology, Ministry of Education of China, College of Life Sciences; 2Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Sustainable Resources Processing and Advanced Materials of Hunan Province, Ministry of Education of China, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, China*These authors contributed equally to this workBackground: Smaller nanoparticles facilitate the delivery of DNA into cells through endocytosis and improve transfection efficiency. The aim of this study was to determine whether protamine sulfate-coated calcium phosphate (PS-CaP could stabilize particle size and enhance transfection efficiency.Methods: pEGFP-C1 green fluorescence protein was employed as an indicator of transfection efficiency. Atomic force microscopy was used to evaluate the morphology and the size of the particles, and an MTT assay was introduced to detect cell viability and inhibition. The classical calcium phosphate method was used as the control.Results: Atomic force microscopy images showed that the PS-CaP were much smaller than classical calcium phosphate particles. In 293 FT, HEK 293, and NIH 3T3 cells, the transfection efficiency of PS-CaP was higher than for the classical calcium phosphate particles. The difference in efficiencies implies that the smaller nanoparticles may promote the delivery of DNA into cells through endocytosis and could improve transfection efficiency. In addition, PS-CaP could be used to transfect HEK 293 cells after one week of storage at 4°C with a lesser extent of efficiency loss compared with classical calcium phosphate, indicating that protamine sulfate may increase the stability of calcium phosphate nanoparticles. The cell viability inhibition assay indicated that

  16. 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

  17. Exocrine pancreatic enzyme and calcium secretion in health and pancreatitis.

    OpenAIRE

    Clain, J E; Barbezat, G O; Marks, I N

    1981-01-01

    Calcium, enzyme, and total protein secretion were measured in secretin stimulated pancreatic juice in health, "early" chronic pancreatitis, and in chronic calcific pancreatitis. Increased concentrations of trypsin, total protein, and calcium, and increased outputs of calcium and protein were shown to be present in the "early" stages of the disease, indicating that an environment conducive to the formation of protein plugs and possibly later calcification already exists.

  18. Radially expanding transglial calcium waves in the intact cerebellum

    OpenAIRE

    Hoogland, Tycho M; Kuhn, Bernd; Göbel, Werner; Huang, Wenying; Nakai, Junichi; HELMCHEN, Fritjof; Flint, Jane; Wang, Samuel S.-H.

    2009-01-01

    Multicellular glial calcium waves may locally regulate neural activity or brain energetics. Here, we report a diffusion-driven astrocytic signal in the normal, intact brain that spans many astrocytic processes in a confined volume without fully encompassing any one cell. By using 2-photon microscopy in rodent cerebellar cortex labeled with fluorescent indicator dyes or the calcium-sensor protein G-CaMP2, we discovered spontaneous calcium waves that filled approximately ellipsoidal domains of ...

  19. IAEA coordinated research project (CRP). The use of selected safety indicators (concentrations, fluxes) in the assessment of radioactive waste disposal. Report 5: Chemical weathering rates on the Baltic Shield of Finland for use as indicators of nuclear waste repository safety

    International Nuclear Information System (INIS)

    In this report the available information from the literature on chemical erosion and weathering rates in Finland and northern Sweden is reviewed and experimental data from recent followup studies in defined catchments is discussed. In glaciated terrain as in Finland the best estimates of chemical erosion rates are obtained when geochemical data of glacial till is used. Elemental fluxes in free-flowing rivers and river-lake systems have been studied in greater detail only in a few case studies. The Kalix river drainage basin investigations gave evidence that the mobilization of rare earth elements (REE) is determined by weathering processes in the upper till layers and that the C-horizon below about 0.75 m depth or generally below the groundwater table is practically unaffected by weathering. Also the removal of U from the watershed was found to happen mostly by groundwater flow through predominantly shallow aquifers. Another type of case study is constrained to regions where certain phenomena cause enhanced trace metal mobilization, as in a region stretched along the western coast of Finland where land-uplift exposes clay sediments rich in sulphides above the groundwater level, with the consequence of increased mobilization of a number of heavy metals. Very little quantitative information on elemental flux balances is available from river-lake systems. Some modelling has been attempted on one great lake system the lake Paeijaenne by use of fall-out nuclides. From the same lake a detailed record of sedimentation rates covering the whole period from the end of the latest glaciation to present is available and erosion rate variations since the end of the latest glaciation can be assessed. The main part of this study focusses on investigations of well-defined small catchments over a longer time period, where groundwater is discharging in springs. Geochemical fluxes worth mentioning seem to be constrained to the surficial geological layers which include overburden and

  20. Correlation between Biochemical Oxygen Demand and Chemical Oxygen Demand for Various Wastewater Treatment Plants in Egypt to Obtain the Biodegradability Indices

    OpenAIRE

    Khaled Zaher Abdallah; Gina Hammam

    2014-01-01

    Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) are the most commonly used parameters for the characterization of wastewaters. Both of these parameters have advantages and disadvantages, and the choice usually depends on many factors such as the time period required to determine each one of them. It is essential to obtain a correlation between BOD5 and COD for various wastewater treatment plants, to help in the design and operation of these plants. In this paper, the biodegr...

  1. 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.``

  2. Generation of a Homozygous Transgenic Rat Strain Stably Expressing a Calcium Sensor Protein for Direct Examination of Calcium Signaling

    OpenAIRE

    Kornélia Szebényi; András Füredi; Orsolya Kolacsek; Enikő Pergel; Zsuzsanna Bősze; Balázs Bender; Péter Vajdovich; József Tóvári; László Homolya; Gergely Szakács; László Héja; Ágnes Enyedi; Balázs Sarkadi; Ágota Apáti; Orbán, Tamás I.

    2015-01-01

    In drug discovery, prediction of selectivity and toxicity require the evaluation of cellular calcium homeostasis. The rat is a preferred laboratory animal for pharmacology and toxicology studies, while currently no calcium indicator protein expressing rat model is available. We established a transgenic rat strain stably expressing the GCaMP2 fluorescent calcium sensor by a transposon-based methodology. Zygotes were co-injected with mRNA of transposase and a CAG-GCaMP2 expressing construct, an...

  3. 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.

  4. 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...

  5. 40 CFR 721.10012 - Manganate (MnO21-), calcium (2:1).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Manganate (MnO21-), calcium (2:1). 721... Substances § 721.10012 Manganate (MnO21-), calcium (2:1). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as manganate (MnO2 1 -), calcium (2:1) (PMN...

  6. Modulation of intestinal absorption of calcium

    International Nuclear Information System (INIS)

    Absorption of ingested calcium (2ml of a 10mM CaCl2 solution + 45Ca) by the adult rat was shown to be facilitated by the simultaneous ingestion of an active carbohydrate, L-arabinose. As the carbohydrate concentration is increased from 10 to 200mM, the absorption of calcium is maximised at a level corresponding to about twice the control absorption level. A similar doubling of calcium absorption is obtained when a 100mM concentration of any one of a number of other carbohydrates is ingested simultaneously with a 10mM CaCl2 solution. Conversely, the simultaneous ingestion of increasing doses (10 to 100mM) of phosphate (NaH2PO4) with a 10mM CaCl2 solution results in decreased 45Ca absorption and retention by the adult rat. The maximum inhibition of calcium absorption by phosphate is independent of the concentration of the ingested calcium solution (from 5 to 50mM CaCl2). The simultaneous ingestion of CaCl2 (10mM) with lactose and sodium phosphate (50 and 10mM respectively) shows that the activation effect of lactose upon 45Ca absorption may be partly dissimulated by the presence of phosphate. These various observations indicate that, within a large concentration range (2 to 50mM CaCl2) calcium absorption appears to be a precisely modulated diffusion process. Calcium absorption varies (between minimum and maximum levels) as a function of the state of saturation by the activators (carbohydrates) and inhibitors (phosphate) of the calcium transport system

  7. Calcium spray dryer waste management: Design guidelines: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1987-09-01

    Calcium spray drying is a commercially available and applied technology used to control SO/sub 2/ emissions. This process is rapidly gaining utility acceptance. Because physical and chemical properties of wastes generated by calcium spray drying differ from those of conventional coal combustion by-products (fly ash and scrubber sludge) typical waste management practices may need to be altered. This report presents technical guidelines for designing and operating a calcium spray drying waste management system. Waste transfer, storage, pretreatment/conditioning, transport and disposal are addressed. The report briefly describes eighteen existing or planned calcium spray drying waste management systems. Results of waste property tests conducted as part of this study, and test data from other studies are reported and compared. Conceptual designs of both new and retrofit calcium spray drying waste management systems also are presented to demonstrate the economic impact of spray drying on waste management. Parametric cost sensitivity analyses illustrate the impact of significant design parameters on waste management costs. Existing calcium spray drying waste management experiences, as well as spray drying waste property data provided the basis for guideline development. Because existing calcium spray drying facilities burn low sulfur coal, this report is considered applicable only to calcium spray drying wastes produced from low sulfur coal. At this time, calcium spray drying is not expected to be feasible for high sulfur coal applications.

  8. 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.

  9. Calcium waves induced by large voltage pulses in fish keratocytes.

    OpenAIRE

    Brust-Mascher, I; Webb, W W

    1998-01-01

    Intracellular calcium waves in fish keratocytes are induced by the application of electric field pulses with amplitudes between 55 and 120 V/cm and full width at half-maximum of 65-100 ms. Calcium concentrations were imaged using two-photon excited fluorescence microscopy (Denk et al., 1990 Science. 248:73-76; Williams et al. 1994 FASEB J. 8:804-813) and the ratiometric calcium indicator indo-1. The applied electric field pulses induced waves with fast calcium rise times and slow decays, whic...

  10. Diagram of Calcium Movement in the Human Body

    Science.gov (United States)

    2002-01-01

    This diagram shows the normal pathways of calcium movement in the body and indicates changes (green arrows) seen during preliminary space flight experiments. Calcium plays a central role because 1) it gives strength and structure to bone and 2) all types of cells require it to function normally. To better understand how and why weightlessness induces bone loss, astronauts have participated in a study of calcium kinetics -- that is, the movement of calcium through the body, including absorption from food, and its role in the formation and breakdown of bone.

  11. Dense and porous titanium substrates with a biomimetic calcium phosphate coating

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, A.A., E-mail: aantunesr@yahoo.com.br [Powder Technology Laboratory, Materials Processing and Characterization Division, National Institute of Technology, No. 82 Venezuela Avenue, Room 602, 20081-312 Rio de Janeiro, RJ (Brazil); Balestra, R.M. [Powder Technology Laboratory, Materials Processing and Characterization Division, National Institute of Technology, No. 82 Venezuela Avenue, Room 602, 20081-312 Rio de Janeiro, RJ (Brazil); Rocha, M.N. [Metallurgical and Materials Engineering Program, COPPE, Federal University of Rio de Janeiro, P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil); Peripolli, S.B. [Materials Metrology Division, National Institute of Metrology, Normalization and Quality, No. 50 Nossa Senhora das Gracas Street, Building 3, 25250-020 Duque de Caxias, RJ (Brazil); Andrade, M.C. [Polytechnic Institute of Rio de Janeiro, Rio de Janeiro State University, s/n, Alberto Rangel Street, 28630-050 Nova Friburgo, RJ (Brazil); Pereira, L.C. [Metallurgical and Materials Engineering Program, COPPE, Federal University of Rio de Janeiro, P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil); Oliveira, M.V. [Powder Technology Laboratory, Materials Processing and Characterization Division, National Institute of Technology, No. 82 Venezuela Avenue, Room 602, 20081-312 Rio de Janeiro, RJ (Brazil)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer A biomimetic coating method with simplified solution is proposed. Black-Right-Pointing-Pointer Titanium substrates are submitted to chemical and heat treatments. Black-Right-Pointing-Pointer Titanium substrates are coated with biocompatible calcium phosphate phases. Black-Right-Pointing-Pointer The simplified solution shows potential to be applied as a coating technique. - Abstract: The present work studied a biomimetic method using a simplified solution (SS) with calcium and phosphorus ions for coating titanium substrates, in order to improve their bioactivity. Commercially pure titanium dense sheet, microporous and macroporous titanium samples, both produced by powder metallurgy, were treated in NaOH solution followed by heat-treating and immersed in SS for 7, 14 or 21 days. The samples characterization was performed by quantitative metallographic analysis, confocal scanning optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and low angle X-ray diffraction. The results showed coatings with calcium phosphate precipitation in all samples, with globular or plate-like morphology, typical of hydroxyapatite and octacalcium phosphate, respectively, indicating that the solution (SS) has potential for coating titanium substrates. In addition, the different surfaces of substrates had an effect on the formed calcium phosphate phase and thickness of coatings, depending on the substrate type and imersion time in the simplified solution.

  12. 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)

  13. Effects of calcium chelators on calcium distribution and protein solubility in rennet casein dispersions.

    Science.gov (United States)

    McIntyre, Irene; O' Sullivan, Michael; O' Riordan, Dolores

    2016-04-15

    This study investigated the effects of calcium chelating salts on calcium-ion activity (ACa(++)), calcium distribution, and protein solubility in model CaCl2 solutions (50 mmol L(-1)) or rennet casein dispersions (15 g/100 g). Disodium phosphate and trisodium citrate at concentrations of 10 and 30 mmol L(-1) and at ratios of 1:0, 2:1, 1:1, 1:2 and 0:1 were added to both systems. The CaCl2 system, despite its simplicity, was a good indicator of chelating salt-calcium interactions in rennet casein dispersions. Adding trisodium citrate either alone or as part of a mixed chelating salt system resulted in high levels of dispersed "chelated" calcium; conversely, disodium phosphate addition resulted in lower levels, while the ACa(++) decreased with increasing concentration of both chelating salts. Neither chelating salt produced high levels of soluble protein. Thus calcium chelating salts may play a more subtle role in modulating hydration during manufacture of casein-based matrices than simply solubilising calcium or protein. PMID:26616945

  14. 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.

  15. 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.

  16. Chemical sensor

    Science.gov (United States)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  17. Use of genetically encoded calcium indicators (GECIs combined with advanced motion tracking techniques to examine the behavior of neurons and glia in the enteric nervous system of the intact murine colon

    Directory of Open Access Journals (Sweden)

    Grant Willem Hennig

    2015-11-01

    Full Text Available Genetically encoded Ca2+ indicators (GECIs have been used extensively in many body systems to detect Ca2+ transients associated with neuronal activity. Their adoption in enteric neurobiology has been slower, although they offer many advantages in terms of selectivity, signal-to-noise and non-invasiveness. Our aims were to utilize a number of cell-specific promoters to express the Ca2+ indicator GCaMP3 in different classes of neurons and glia to determine their effectiveness in measuring activity in enteric neural networks during colonic motor behaviors. We developed several GCaMP3 mice: 1 Wnt1-GCaMP3, all enteric neurons and glia; 2 GFAP-GCaMP3, enteric glia; 3 nNOS-GaMP3, enteric nitrergic neurons, and 4 ChAT-GCaMP3, enteric cholinergic neurons. These mice allowed us to study the behavior of the enteric neurons in the intact colon maintained at a physiological temperature, especially during the colonic migrating motor complex (CMMC, using low power Ca2+ imaging. In this preliminary study, we observed neuronal and glial cell Ca2+ transients in specific cells in both the myenteric and submucous plexus in all of the transgenic mice variants. The number of cells that could be simultaneously imaged at low power (100-1000 active cells through the undissected gut required advanced motion tracking and analysis routines. The pattern of Ca2+ transients in myenteric neurons showed significant differences in response to spontaneous, oral or anal stimulation. Brief anal elongation or mucosal stimulation, which evokes a CMMC, were the most effective stimuli and elicited a powerful synchronized and prolonged burst of Ca2+ transients in many myenteric neurons, especially when compared with the same neurons during a spontaneous CMMC. In contrast, oral elongation, which normally inhibits CMMCs, appeared to suppress Ca2+ transients some of the neurons active during a spontaneous or an anally evoked CMMC. The activity in glial networks appeared to follow neural

  18. Role of Calcium Hydroxide in Endodontics: A Review

    Directory of Open Access Journals (Sweden)

    Arun A

    2012-01-01

    Full Text Available Calcium hydroxide is a multipurpose agent, and there have been an increasing number of indications for its use in endodontics. Some of its indications include inter-appointment intracanal medicaments, endodontic sealers, pulp capping agents, apexification, pulpotomy and weeping canals. The purpose of this article is to review the properties, advantages, disadvantages and various indications for the use of calcium hydroxide in endodontics.

  19. 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

  20. Rankings of iron, vitamin D, and calcium intakes in relation to maternal characteristics of pregnant Canadian women.

    Science.gov (United States)

    Morisset, Anne-Sophie; Weiler, Hope A; Dubois, Lise; Ashley-Martin, Jillian; Shapiro, Gabriel D; Dodds, Linda; Massarelli, Isabelle; Vigneault, Michel; Arbuckle, Tye E; Fraser, William D

    2016-07-01

    Iron, vitamin D, and calcium intakes in the prenatal period are important determinants of maternal and fetal health. The objective of this study was to examine iron, vitamin D, and calcium intakes from diet and supplements in relation to maternal characteristics. Data were collected in a subsample of 1186 pregnant women from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a cohort study including pregnant women recruited from 10 Canadian sites between 2008 and 2011. A food frequency questionnaire was administered to obtain rankings of iron, calcium, and vitamin D intake (16-21 weeks of pregnancy). Intakes from supplements were obtained from a separate questionnaire (6-13 weeks of pregnancy). Women were divided into 2 groups according to the median total intake of each nutrient. Supplement intake was an important contributor to total iron intake (median 74%, interquartile range (IQR) 0%-81%) and total vitamin D intake (median 60%, IQR 0%-73%), while the opposite was observed for calcium (median 18%, IQR 0%-27%). Being born outside of Canada was significantly associated with lower total intakes of iron, vitamin D, and calcium (p ≤ 0.01 for all). Consistent positive indicators of supplement use (iron, vitamin D, and calcium) were maternal age over 30 years and holding a university degree. In conclusion, among Canadian women, the probability of having lower iron, vitamin D, and calcium intakes is higher among those born outside Canada; supplement intake is a major contributor to total iron and vitamin D intakes; and higher education level and age over 30 years are associated with supplement intake. PMID:27324651

  1. Discourse and Review of Environmental Quality of River Bodies in India: An Appraisal of Physico-chemical and Biological Parameters as Indicators of Water Quality

    OpenAIRE

    Kumar Manoj; Pratap Kumar Padhy

    2015-01-01

    The present manuscript is an account of the studies conducted on some well known surface water bodies in India, with special emphasis on the river systems, to evaluate their quality status. The review covers the water quality estimation and identification of sources contributing to water quality deterioration. Commonly employed physicochemical and biological parameters as indicators of water quality have been thoroughly discussed. Some possible measures to prevent and control pollution of wat...

  2. Calcium and vitamin D supplementation increases spinal BMD in healthy, postmenopausal women

    DEFF Research Database (Denmark)

    Baeksgaard, L; Andersen, K P; Hyldstrup, Lars

    1998-01-01

    . Together with significant changes in serum calcium and serum parathyroid hormone, this indicates that a long-term calcium and vitamin supplement of 1 g elementary calcium (calcium carbonate) and 14 micrograms vitamin D3 increases intestinal calcium absorption. A positive effect on BMD was demonstrated......We undertook a double-masked, randomized, placebo-controlled trial to evaluate the effect of a calcium and vitamin D supplement and a calcium supplement plus multivitamins on bone loss at the hip, spine and forearm. The study was performed in 240 healthy women, 58-67 years of age. Duration of...... treatment was 2 years. Bone mineral density (BMD) was measured at the lumbar spine, hip and forearm. A dietary questionnaire was administered twice during the study and revealed a fairly good calcium and vitamin D intake (919 mg calcium/day; 3.8 micrograms vitamin D/day). An increase in lumbar spine BMD of...

  3. A quantitative model for presynaptic free calcium dynamics during the induction of long-term effects

    CERN Document Server

    Erler, F; Soff, G; Erler, Frido; Meyer-Hermann, Michael; Soff, Gerhard

    2002-01-01

    The presynaptic free calcium dynamics of neurons due to various stimulation protocols is investigated in a mathematical model. Especially, connections between free calcium dynamics and the induction of synaptic long-term effects are considered. The model includes calcium influx through voltage-directed calcium channels, calcium buffering by endogenous and exogenous buffers as well as calcium efflux through ATP-driven plasma membrane calcium pumps and sodium/calcium exchangers. A classification of parameters into universal (widely independent of neuron types) and specific ones (depending on neuron type and experimental setup) allows the applications of the model to different classes of neurons and experiments. This is demonstrated for single boutons of pyramidal neurons of the rat neocortex. The model parameters are determined using corresponding fluorescence measurements. The model enables us to reconstruct the free calcium dynamics in neurons as it would have been without fluorescence indicators starting fro...

  4. Preparation of novel bioactive nano-calcium phosphate-hydrogel composites

    Energy Technology Data Exchange (ETDEWEB)

    Juhasz, Judith A; Best, Serena M; Bonfield, William, E-mail: jaj33@cam.ac.u [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2010-02-15

    Nano-sized hydroxyapatite (nHA) and carbonate-substituted hydroxyapatite (nCHA) particles were incorporated into a poly-2-hydroxyethylmethacrylate/polycaprolactone (PHEMA/PCL) hydrogel at a filler content of 10 wt%. Fourier transform infrared absorption, transmission electron microscopy, x-ray diffraction and scanning electron microscopy were used to analyse the physical and chemical characteristics of the calcium phosphate fillers and resultant composites. Nano-sized calcium phosphate particles were produced with a needle-like morphology, average length of 50 nm and an aspect ratio of 3. The nanoparticles were uniformly distributed in the polymer matrix. The addition of both HA and CHA in nano-form enhanced the bioactivity and biocompatibility of the PHEMA/PCL matrix. The carbonate-substitution has allowed for improved bioactivity and biocompatibility of the resultant composite, indicating the potential of this material for use in bone tissue engineering.

  5. Preparation of novel bioactive nano-calcium phosphate-hydrogel composites

    International Nuclear Information System (INIS)

    Nano-sized hydroxyapatite (nHA) and carbonate-substituted hydroxyapatite (nCHA) particles were incorporated into a poly-2-hydroxyethylmethacrylate/polycaprolactone (PHEMA/PCL) hydrogel at a filler content of 10 wt%. Fourier transform infrared absorption, transmission electron microscopy, x-ray diffraction and scanning electron microscopy were used to analyse the physical and chemical characteristics of the calcium phosphate fillers and resultant composites. Nano-sized calcium phosphate particles were produced with a needle-like morphology, average length of 50 nm and an aspect ratio of 3. The nanoparticles were uniformly distributed in the polymer matrix. The addition of both HA and CHA in nano-form enhanced the bioactivity and biocompatibility of the PHEMA/PCL matrix. The carbonate-substitution has allowed for improved bioactivity and biocompatibility of the resultant composite, indicating the potential of this material for use in bone tissue engineering.

  6. Calcium wave of Brain Astrocytes

    Science.gov (United States)

    Cornell Bell, A. H.

    1997-03-01

    Time lapse confocal scanning laser microscopy was used to study hippocampal astrocyte cultures loaded with a calcium indicator, Fluo3-AM (4 uM). kThe neurotransmitter kainate (100uM) overwhelms the Na+-buffering capacity of astrocytes within 100 sec resulting in reversal of the Na+/Ca2+ exchanger. This results in a subcellular site where Ca2+ entering the cytoplasm contributes to a long-distance Ca2+ wave which travels at 20 um/sec without decrement. Image analysis has shown calcium waves not only at a high Kainate dose, but also at a low Kainate dose, e.g. 10uM. These are, however, shortlived and burried in an extremely noisy background and only detectable by analyzing the calcium waves images for spatio-temporal coherence. As the kainate dose increases, more large scale coherent structures with visible geometric features (spiral waves and target waves) can be observed. Multiple spiral waves are produced when the Kainate dose increases to 100 uM. These waves travel at a constant velocity across entire microscope fields for long time periods (>30 mins). Na+ channels have no effect on the Kainate wave. Voltage-gated Ca2+ channels are not involved and Ca2+ enters through reversal of the exchanger. Ca2+ release from stores does not contribute to the kainate wave. Removal of Na+ or Ca2+ from outside and the specific Na+/Ca2+ exchange inhibitor benzamil (10 uM) inhibit the kainate wave. A functional antibody to alpha6-Integrin which is localized to membrane regions between cells inhibits the spread of the kainate wave in a dose and time-dependent manner. Fluorescence Recovery after Photobleach (FRAP) techniques indicate that gap junctions remain open between cells. This would imply that Ca2+ or IP3 need not pass through the gap junction, but reversal of the exchanger would propel the Ca2+ wave at the cell surface.

  7. 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

  8. Chemical contamination of the Rybinsk Reservoir, northwest Russia: Relationship between liver polychlorinated biphenyls (PCB) content and health indicators in bream (Abramis brama)

    Science.gov (United States)

    Chuiko, G.M.; Tillitt, D.E.; Zajicek, J.L.; Flerov, B.A.; Stepanova, V.M.; Zhelnin, Y.Y.; Podgornaya, V.A.

    2007-01-01

    The Rybinsk Reservoir (Russia) is the largest artificial waterbody in Europe (4550 km2) and provides drinking water for population of the cities located along the coast line. Industrialization in Cherepovets at the northeastern portion of the reservoir, including one of the largest metallurgical facilities in Europe, has resulted in chemical contamination of the reservoir. The extent of polychlorinated biphenyls (PCB) contamination in bream liver, a common fish species, taken from six locations in the Rybinsk Reservoir and Volga River, and biochemical and morphometric biomarkers of fish health were investigated. Liver PCB concentrations ranged from non-detected to 3.4 ??g/g wet wt of liver, with the greatest concentrations found in fish taken near the industrialized area in Sheksna Reach of Rybinsk Reservoir. The source of the bream contamination is the PCB pollution of bottom organisms and sediments conditioned with industrialization facilities of Cherepovets. The patterns of the PCB congeners in the livers of bream taken near Cherepovets were similar at all of the stations that were sampled around the reservoir and Volga River. Among the common fish health biomarkers used only liver total ChE activity and liver-somatic index in bream near Cherepovets can reflect environmental pollution. Other morphometric (FCF, Clark's condition factors, and spleen-somatic index) and biochemical (protein content and acetylcholinesterase activity in the brain) biomarkers related with fish health varied among locations, but were not correlated to the concentrations of PCBs in the bream livers. ?? 2006 Elsevier Ltd. All rights reserved.

  9. Oxidative stress indicators and chemical contaminants in East Pacific green turtles (Chelonia mydas) inhabiting two foraging coastal lagoons in the Baja California peninsula.

    Science.gov (United States)

    Labrada-Martagón, Vanessa; Rodríguez, Paola A Tenorio; Méndez-Rodríguez, Lia C; Zenteno-Savín, Tania

    2011-08-01

    In order to determine the potential effects of contaminants in juveniles of East Pacific green turtle, Chelonia mydas, captured alive, circulating trace metal and organochlorine pesticide concentrations were correlated with body condition, antioxidant enzyme activities and lipid peroxidation levels. Turtles were sampled in Punta Abreojos (PAO) and Bahía Magdalena (BMA). Turtles from PAO showed higher silicon and cadmium concentrations, but lower α-hexachlorocyclohexane, γ-hexachlorocyclohexane, hexachlorobenzene and aldrin concentrations than individuals from BMA. In BMA cadmium concentration decreased as the standard carapace length of the turtles increased. In PAO concentrations of α-hexachlorocyclohexane, heptachlor and hexachlorobenzene were positively correlated with the weight of the individuals. Lipid peroxidation levels were positively correlated with cadmium concentrations. In turtles captured in PAO, enzymatic antioxidant activities correlated mostly with pesticide concentrations, while in individuals from BMA enzyme activities were correlated with trace element concentrations. Correlations between antioxidant enzyme activities and concentration of xenobiotics suggest physiological sensitivity of East Pacific green turtles to chemicals. Regional differences found could be influenced by habitat conditions such as currents, upwellings (PAO) and agricultural activities (BMA). We suggest that, combined, circulating contaminant concentrations, lipid peroxidation levels and antioxidant enzyme activities in sea turtles could be used as biomarkers of the habitat conditions. PMID:21377544

  10. Physicochemical characterization of zinc-substituted calcium phosphates

    Indian Academy of Sciences (India)

    DOROTA WALCZYK; DAGMARA MALINA; MILENA KRÓL; KLAUDIA PLUTA; AGNIESZKA SOBCZAK-KUPIEC

    2016-04-01

    Biocompatible and bioactive calcium phosphates can make chemical bonds with living bones. Improvement of their biological and physicochemical properties can be achieved by doping with various ions that are presented in natural apatites of bones. These substitutions influence lattice parameters, structure and morphology of apatites. In recent times great attention has been devoted to zinc ions that are the second most abundant trace element present in bones. Zinc embedded into calcium phosphate may enhance the bone formation and in addition exhibits antifungal and antibacterial properties. Therefore, it is rational to form structures incorporated with this ion. In this paper the incorporation of the Zn ions into natural and synthetic calcium phosphates has been reported.Natural hydroxyapatites (HAs) applied in this study were derived mainly from pork bones whereas both brushite and synthetic were formed using wet chemical methods. Ambient temperature synthesis leads to the formation ofbrushite, whereas the process performed at elevated temperature gives HA. Subsequently, attained structures were modified with Zn ions by using in situ or sorption procedures. Phase composition and morphology of obtained materials were determined by means of X-ray diffractometry, Fourier transform infrared spectroscopy and scanning electron microscopy equipped with energy-dispersive spectroscopy. Introduced XRD patterns depict changes of the crystallinity of HA with the increase in the amount of embedded zinc ions. On the contrary, no changes of the crystallinity were observed for the brushite doped with Zn ions. Morphology of attained powders, visualized using scanningelectron microscopy exemplified structural changes between calcium phosphates conjugated with zinc ions. Many authors report that the addition of small amounts of Zn ions leads to loss of crystallinity and decrease of lattice parameters. Interestingly, upon addition of Zn ions to the natural and synthetic HAp by sorption

  11. Behaviour of calcium carbonate in sea water

    Science.gov (United States)

    Cloud, P.E., Jr.

    1962-01-01

    Anomalies in the behaviour of calcium carbonate in natural solutions diminish when considered in context. Best values found by traditional oceanographie methods for the apparent solubility product constant K'CaCO3 in sea water at atmospheric pressure are consistent mineralogically-at 36 parts per thousand salinity and T-25??C, K'aragonlte is estimated as 1.12 ?? 10-6 and K'calcite as 0.61 ?? 10-6. At 30??C the corresponding values are 0.98 ?? 10-6 for aragonite and 0.53 ?? 10-6 for calcite. Because the K' computations do not compensate for ionic activity, however, they cannot give thermodynamically satisfactory results. It is of interest, therefore, that approximate methods and information now available permit the estimation from the same basic data of an activity product constant KCaCO3 close to that found in solutions to which Debye-Hu??ckel theory applies. Such methods indicate approximate Karagonite 7.8 ?? 10-9 for surface sea water at 29??C; Kcalcite would be proportionately lower. Field data and experimental results indicate that the mineralogy of precipitated CaCO3 depends primarily on degree of supersaturation, thus also on kinetic or biologic factors that facilitate or inhibit a high degree of supersaturation. The shallow, generally hypersaline bank waters west of Andros Island yield aragonitic sediments with O18 O16 ratios that imply precipitation mainly during the warmer months, when the combination of a high rate of evaporation, increasing salinity (and ionic strength), maximal temperatures and photosynthetic removal of CO2 result in high apparent supersaturation. The usual precipitate from solutions of low ionic strength is calcite, except where the aragonite level of supersaturation is reached as a result of diffusion phenomena (e.g. dripstones), gradual and marked evaporation, or biologic intervention. Published data also suggest the possibility of distinct chemical milieus for crystallographic variations in skeletal calcium carbonate. It appears

  12. Chemical analysis of radioactive liquid wastes. Volumetric dosage of sulfates in the presence of phosphates, 'nitrochromazo' being used as an indicator

    International Nuclear Information System (INIS)

    A simple titration technique of SO4 ions in the presence of PO4 ions has been perfected. The pH of the medium is stated to 1,7-2,0 the colour of the indicator changes from violet to blue. The method is quick, accurate and can be fitted to biological studies or in the industry of fertilizes. The synthesis method of nitrochromazo (acid 2, 7 bis (4 nitro 2 sulfobenzene 1 azo) 1-8 hydroxynaphthalene 3-6 disulfonic) is described. (authors)

  13. 21 CFR 184.1201 - Calcium glycerophosphate.

    Science.gov (United States)

    2010-04-01

    ... ingredient meets the specifications of the “Food Chemicals Codex,” 3d Ed. (1981), pp. 51-52, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium glycerophosphate. 184.1201 Section...

  14. The Influence of No-Till, Conventional Tillage and Nitrogen Fertilization on Physico-Chemical and Biological Indicators After Three Years of Monoculture Barley

    Directory of Open Access Journals (Sweden)

    Cristina Menta

    2008-12-01

    Full Text Available An experimental trial was carried out over three years at Cavacurta (Po valley, Italy on continuous barley. The soil was a coarse-loamy over sandy, mixed, mesic Fluventic Ustochrept. The experimental design was a split-plot with four replicates; the main factor was the soil management system (conventional tillage, CT, and no-tillage, NT, while the secondary factor was the nitrogen fertilization (N0 = 0, N1 = 50 and N2 = 90 kg N ha-1 year-1. At the end of the third year soil samples were taken in all plots at four depths (0-5, 5-10, 10-15 and 15-20 cm. For these samples, pH, organic matter, total N, available P and cation exchange capacity were determined. On the contrary, water aggregate stability was determined for a single layer (0-20 cm depth, excluding the N1 level of fertilization. The biological indicator, QBS-ar index, was studied only in the layer 0-10 cm. Statistical analysis shows that no-till positively influenced all the indices except for CEC and QBS-ar. N fertilization had significant effects on CEC only; in the upper layer, the value in N2 subplots was of approx. 1 cmol+ kg-1 higher than in N0 and N1 subplots. There was no significant interaction for any of the indices. As regards only the 0-20 cm layer, the most important results are as follows. The organic matter content in NT plots was significantly higher than in CT plots (32.6 vs 29.8 g kg-1, as was the total N (2.11 vs 1.97 g kg-1. No-till also had a very clear effect on the Olsen-P (12.3 vs 9.3 mg kg-1. The most remarkable result was found for the water aggregate stability: for NT plots the value was 246% higher than for CT plots (34.3 vs 9.9%. As regards the microarthropod community, the value of the QBS-ar index was between 90 and 126, a typical range for soil under barley.

  15. Alkenone δD as an ecological indicator: A culture and field study of physiologically-controlled chemical and hydrogen-isotopic variation in C37 alkenones

    Science.gov (United States)

    Wolhowe, Matthew D.; Prahl, Fredrick G.; Langer, Gerald; Oviedo, Angela Maria; Ziveri, Patrizia

    2015-08-01

    A combined culture and field study was conducted in order to (1) more firmly identify the physiological controls on hydrogen isotopic composition of C37 alkenones produced by open-ocean coccolithophores and (2) determine the degree to which these controls are manifested in a natural water column. Nutrient-limitation experiments in culture, combined with previously published data, show that net fractionation between the growth medium and alkenones (αK37) varies with cellular alkenone content and production rate, and, by extension, growth phase. It is hypothesized that the relationship of αK37 with cellular alkenone content and production rate is due to increased use of anabolic NADPH in response to high rates of lipid synthesis. Euphotic zone profiles of δDK37, measured in suspended material from the Gulf of California and Eastern Tropical North Pacific, decreased with depth and light availability, and did not correlate in any expected way with previously-suggested controls on αK37. It is possible that the field data are driven by behavior in light-limited cells that is not represented by the available, nutrient-limited culture data. If true, δDK37 may have utility as an indicator of production depth in settings prone to subsurface production maxima. Relationships between αK37, cell density, and the carbon-isotopic fractionation term εp, however, suggest that αK37 acts an indicator of growth rate, which in this setting is only partially dependent on light, consistent with our interpretation of the culture data. If this latter interpretation proves correct, δDK37 may be a powerful ecological proxy specific to these climatically-important, calcifying, temperature-encoding species.

  16. A mathematical model of T lymphocyte calcium dynamics derived from single transmembrane protein properties

    Directory of Open Access Journals (Sweden)

    Christine Dorothee Schmeitz

    2013-09-01

    Full Text Available Fate decision processes of T lymphocytes are crucial for health and disease. Whether a T lymphocyte is activated, divides, gets anergic or initiates apoptosis depends on extracellular triggers and intracellular signalling. Free cytosolic calcium dynamics plays an important role in this context. The relative contributions of store-derived calcium entry and calcium entry from extracellular space to T lymphocyte activation are still a matter of debate. Here we develop a quantitative mathematical model of T lymphocyte calcium dynamics in order to establish a tool which allows to disentangle cause-effect relationships between ion fluxes and observed calcium time courses. The model is based on single transmembrane protein characteristics which have been determined in independent experiments. This reduces the number of unknown parameters in the model to a minimum and ensures the predictive power of the model. Simulation results are subsequently used for an analysis of whole cell calcium dynamics measured under various experimental conditions. The model accounts for a variety of these conditions, which supports the suitability of the modelling approach. The simulation results suggest a model in which calcium dynamics dominantly relies on the opening of channels in calcium stores while calcium entry through calcium-release activated channels (CRAC is more associated with the maintenance of the T lymphocyte calcium levels and prevents the cell from calcium depletion. Our findings indicate that CRAC guarantees a long-term stable calcium level which is required for cell survival and sustained calcium enhancement.

  17. Calcium regulates caveolin-1 expression at the transcriptional level

    International Nuclear Information System (INIS)

    Highlights: ► Caveolin-1 expression is regulated by calcium signaling at the transcriptional level. ► An inhibitor of or siRNA to L-type calcium channel suppressed caveolin-1 expression. ► Cyclosporine A or an NFAT inhibitor markedly reduced caveolin-1 expression. ► Caveolin-1 regulation by calcium signaling is observed in several mouse cell lines. -- Abstract: Caveolin-1, an indispensable component of caveolae serving as a transformation suppressor protein, is highly expressed in poorly metastatic mouse osteosarcoma FBJ-S1 cells while highly metastatic FBJ-LL cells express low levels of caveolin-1. Calcium concentration is higher in FBJ-S1 cells than in FBJ-LL cells; therefore, we investigated the possibility that calcium signaling positively regulates caveolin-1 in mouse FBJ-S1 cells. When cells were treated with the calcium channel blocker nifedipine, cyclosporin A (a calcineurin inhibitor), or INCA-6 (a nuclear factor of activated T-cells [NFAT] inhibitor), caveolin-1 expression at the mRNA and protein levels decreased. RNA silencing of voltage-dependent L-type calcium channel subunit alpha-1C resulted in suppression of caveolin-1 expression. This novel caveolin-1 regulation pathway was also identified in mouse NIH 3T3 cells and Lewis lung carcinoma cells. These results indicate that caveolin-1 is positively regulated at the transcriptional level through a novel calcium signaling pathway mediated by L-type calcium channel/Ca2+/calcineurin/NFAT.

  18. Serum calcium levels are not associated with coronary heart disease

    Directory of Open Access Journals (Sweden)

    Jin Y

    2013-09-01

    Full Text Available Yuelong Jin,* Lianping He,* Quanhai Wang, Yan Chen, Xiaohua Ren, Hui Tang, Xiuli Song, Lingling Ding, Qin Qi, Zhiwei Huang, Jiegen Yu, Yingshui Yao Department of Preventive Medicine, Wannan Medical College, Wuhu, People's Republic of China *These authors contributed equally to this work Background: Numerous studies have reported that low calcium intake is related to a higher prevalence of cardiovascular disease. However, the relationship between serum calcium and coronary heart disease is unclear. The purpose of this study was to compare serum calcium levels in patients with coronary heart disease and those in healthy individuals. Methods: This retrospective, case-control study conducted in the People's Republic of China comprised 380 cases and 379 controls. Serum calcium levels, blood lipids, and anthropometric measurements were measured in both groups. The Student's unpaired t-test or Chi-square test was used to compare differences between cases and controls. Pearson's partial correlation coefficient was used to determine the association between serum calcium, blood lipids, and blood pressure in both groups. Results: Our results indicate that the average level of serum calcium in cases was higher than in controls. Serum calcium levels showed no correlation with any parameter except for triglycerides in either group. Conclusion: Overall, these data suggest that serum calcium has no influence on coronary heart disease or triglyceride levels in the general population. Keywords: serum calcium, hypertension, blood lipids

  19. 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)

  20. Mechanical behavior of a composite interface: Calcium-silicate-hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Palkovic, Steven D.; Moeini, Sina; Büyüköztürk, Oral, E-mail: obuyuk@mit.edu [Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Yip, Sidney [Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-07-21

    The generalized stacking fault (GSF) is a conceptual procedure historically used to assess shear behavior of defect-free crystalline structures through molecular dynamics or density functional theory simulations. We apply the GSF technique to the spatially and chemically complex quasi-layered structure of calcium-silicate-hydrates (C-S-H), the fundamental nanoscale binder within cementitious materials. A failure plane is enforced to calculate the shear traction-displacement response along a composite interface containing highly confined water molecules, hydroxyl groups, and calcium ions. GSF simulations are compared with affine (homogeneous) shear simulations, which allow strain to localize naturally in response to the local atomic environment. Comparison of strength and deformation behavior for the two loading methods shows the composite interface controls bulk shear deformation. Both models indicate the maximum shear strength of C-S-H exhibits a normal-stress dependency typical of cohesive-frictional materials. These findings suggest the applicability of GSF techniques to inhomogeneous structures and bonding environments, including other layered systems such as biological materials containing organic and inorganic interfaces.

  1. Mechanical behavior of a composite interface: Calcium-silicate-hydrates

    International Nuclear Information System (INIS)

    The generalized stacking fault (GSF) is a conceptual procedure historically used to assess shear behavior of defect-free crystalline structures through molecular dynamics or density functional theory simulations. We apply the GSF technique to the spatially and chemically complex quasi-layered structure of calcium-silicate-hydrates (C-S-H), the fundamental nanoscale binder within cementitious materials. A failure plane is enforced to calculate the shear traction-displacement response along a composite interface containing highly confined water molecules, hydroxyl groups, and calcium ions. GSF simulations are compared with affine (homogeneous) shear simulations, which allow strain to localize naturally in response to the local atomic environment. Comparison of strength and deformation behavior for the two loading methods shows the composite interface controls bulk shear deformation. Both models indicate the maximum shear strength of C-S-H exhibits a normal-stress dependency typical of cohesive-frictional materials. These findings suggest the applicability of GSF techniques to inhomogeneous structures and bonding environments, including other layered systems such as biological materials containing organic and inorganic interfaces

  2. Strontium randomly substituting for calcium in fish otolith aragonite.

    Science.gov (United States)

    Doubleday, Zoë A; Harris, Hugh H; Izzo, Christopher; Gillanders, Bronwyn M

    2014-01-01

    The chemistry of fish ear bones (otoliths) is used to address fundamental questions in fish ecology and fisheries science. It is assumed that strontium (Sr), the most important element used in otolith chemistry research, is bound within the aragonitic calcium carbonate lattice of otoliths via random chemical replacement of calcium; however, this has never been tested and three other alternatives exist with regard to how Sr may be incorporated. If any variation in the mode of incorporation occurs, otolith chemistry data may be misinterpreted, impacting how fish and fisheries are understood and managed. Using X-ray absorption spectroscopy (specifically, analysis of extended X-ray absorption fine structure or EXAFS), we investigated how Sr is incorporated within fish otoliths from seven species collected from a range of aquatic environments. For comparison, aragonitic structures from other aquatic taxa (cephalopods and coral) were also analyzed. The results consistently indicated for all samples that Sr randomly replaces Ca within the aragonite lattice. This research explicitly shows how Sr is bound within otoliths and validates a fundamental and long-held assumption in aquatic research. PMID:24299165

  3. Effects of vestibular nerve transection on the calcium incorporation of fish otoliths

    Science.gov (United States)

    Anken, Ralf H.; Edelmann, Elke; Rahmann, Hinrich

    2001-08-01

    Previous investigations revealed that the growth of fish inner ear otoliths (otolith size and calcium-incorporation) depends on the amplitude and the direction of gravity, suggesting the existence of a (negative) feedback mechanism. In search for the regulating unit, the vestibular nerve was transected unilaterally in neonate swordtail fish ( Xiphophorus helleri) which were subsequently incubated in the calcium-tracer alizarin-complexone. Calcium incorporation ceased on the transected head sides, indicating that calcium uptake is neurally regulated.

  4. 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...

  5. Voltage-Gated Calcium Channels in Nociception

    Science.gov (United States)

    Yasuda, Takahiro; Adams, David J.

    Voltage-gated calcium channels (VGCCs) are a large and functionally diverse group of membrane ion channels ubiquitously expressed throughout the central and peripheral nervous systems. VGCCs contribute to various physiological processes and transduce electrical activity into other cellular functions. This chapter provides an overview of biophysical properties of VGCCs, including regulation by auxiliary subunits, and their physiological role in neuronal functions. Subsequently, then we focus on N-type calcium (Cav2.2) channels, in particular their diversity and specific antagonists. We also discuss the role of N-type calcium channels in nociception and pain transmission through primary sensory dorsal root ganglion neurons (nociceptors). It has been shown that these channels are expressed predominantly in nerve terminals of the nociceptors and that they control neurotransmitter release. To date, important roles of N-type calcium channels in pain sensation have been elucidated genetically and pharmacologically, indicating that specific N-type calcium channel antagonists or modulators are particularly useful as therapeutic drugs targeting chronic and neuropathic pain.

  6. Waste indicators

    International Nuclear Information System (INIS)

    The Waste Indicator Project focuses on methods to evaluate the efficiency of waste management. The project proposes the use of three indicators for resource consumption, primary energy and landfill requirements, based on the life-cycle principles applied in the EDIP Project. Trial runs are made With the indicators on paper, glass packaging and aluminium, and two models are identified for mapping the Danish waste management, of which the least extensive focuses on real and potential savings. (au)

  7. Waste indicators

    Energy Technology Data Exchange (ETDEWEB)

    Dall, O.; Lassen, C.; Hansen, E. [Cowi A/S, Lyngby (Denmark)

    2003-07-01

    The Waste Indicator Project focuses on methods to evaluate the efficiency of waste management. The project proposes the use of three indicators for resource consumption, primary energy and landfill requirements, based on the life-cycle principles applied in the EDIP Project. Trial runs are made With the indicators on paper, glass packaging and aluminium, and two models are identified for mapping the Danish waste management, of which the least extensive focuses on real and potential savings. (au)

  8. Quality indicators

    DEFF Research Database (Denmark)

    Hjorth-Andersen, Christian

    1991-01-01

    In recent literature it has been suggested that consumers need have no knowledge of product quality as a number of quality indicators (or signals) may be used as substitutes. Very little attention has been paid to the empirical verification of these studies. The present paper is devoted...... to the issue of how well these indicators perform, using market data provided by consumer magazines from 3 countries. The results strongly indicate that price is a poor quality indicator. The paper also presents some evidence which suggests that seller reputation and easily observable characteristics are also...

  9. Precipitation of calcium carbonate and calcium phosphate under diffusion controlled mixing

    Energy Technology Data Exchange (ETDEWEB)

    Tsigabu Gebrehiwet; James R. Henriksen; Luanjing Guo; Don T. Fox; Hai Huang; Lee Tu; Yoshiko Fujita; Robert W. Smith; George Redden

    2014-07-01

    Multi-component mineral precipitation in porous, subsurface environments is challenging to simulate or engineer when in situ reactant mixing is controlled by diffusion. In contrast to well-mixed systems, the conditions that favor mineral precipitation in porous media are distributed along chemical gradients, which evolve spatially due to concurrent mineral precipitation and modification of solute transport in the media. The resulting physical and chemical characteristics of a mixing/precipitation zone are a consequence of coupling between transport and chemical processes, and the distinctive properties of individual chemical systems. We examined the spatial distribution of precipitates formed in “double diffusion” columns for two chemical systems, calcium carbonate and calcium phosphate. Polyacrylamide hydrogel was used as a low permeability, high porosity medium to maximize diffusive mixing and minimize pressure- and density-driven flow between reactant solutions. In the calcium phosphate system, multiple, visually dense and narrow bands of precipitates were observed that were reminiscent of previously reported Liesegang patterns. In the calcium carbonate system, wider precipitation zones characterized by more sparse distributions of precipitates and a more open channel structure were observed. In both cases, formation of precipitates inhibited, but did not necessarily eliminate, continued transport and mixing of the reactants. A reactive transport model with fully implicit coupling between diffusion, chemical speciation and precipitation kinetics, but where explicit details of nucleation processes were neglected, was able to qualitatively simulate properties of the precipitation zones. The results help to illustrate how changes in the physical properties of a precipitation zone depend on coupling between diffusion-controlled reactant mixing and chemistry-specific details of precipitation kinetics.

  10. 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...

  11. The calcium oxide influence on formation of manganese, calcium pyrovanadate solid solutions

    International Nuclear Information System (INIS)

    The X-ray graphic, derivatographic, microscopic and chemical methods are used to study solid solutions of manganese, calcium pyrovanadates containing 1-10 mass% CaO and the products of interaction of reprocessing charges of vanadium-containing converter slags intended for he formation of manganese and calcium pyrovanadates with additions of calcium oxide within 10-90 mass%. It is established that in the case of 1-6 mass% CaO content in manganese pyrovanadate solid interstitial solutions appear, while at 6-20 mass% CaO - solid substitution solutions form. The results of calculating elementary cell parameters as well as melting temperatures and pyrovanadate solid solution solubility depending on CaO content are presented. The best solubility of introduction solid solutions during vanadium extraction according to the lime technology is found

  12. 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.

  13. 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 ...

  14. Calcium chloride and calcium bromide aqueous solutions of technical and analytical grade in Lemna bioassay.

    Science.gov (United States)

    Vujević, M; Vidaković-Cifrek, Z; Tkalec, M; Tomíc, M; Regula, I

    2000-11-01

    Saturated water solutions of calcium chloride, calcium bromide and their 1:1 mixture are commonly used as "high density brines" for pressure control in oil wells. To compare the effect of these chemicals of technical grade with the effect of the chemicals of analytical grade the Lemna test was used. The multiplication rate, fresh weight, dry to fresh weight ratio, area covered by plants and chlorophyll content were measured as toxicity parameters. The concentrations of tested chemicals were 0.025, 0.05. 0.075 and 0.1 mol dm(-3). Generally, the chemicals of both technical and analytical grade in concentrations of 0.025 mol dm(-3) stimulated the Lemna minor growth, while tested chemicals in concentrations of 0.05 mol dm(-3) did not affect the growth significantly. The exceptions were results obtained by measuring fresh weight. Most of tested chemicals in concentrations of 0.075 mol dm(-3) and all chemicals in concentrations of 0.1 mol dm(-3) reduced the growth. No major differences between effects of tested chemicals of technical and analytical grade on plant growth were observed, except that tested chemicals of analytical grade in concentrations of 0.1 mol dm(-3) increased dry to fresh weight ratio much stronger than chemicals of technical grade. All tested chemicals in all concentrations increased chlorophyll content. After treatment with chemicals of analytical grade much higher increase of chlorophyll a concentration in comparison to increase of chlorophyll b was noticed, while chemicals of technical grade caused more prominent increase of chlorophyll b. PMID:11057678

  15. Calcium signaling and T-type calcium channels in cancer cell cycling

    Institute of Scientific and Technical Information of China (English)

    James T Taylor; Xiang-Bin Zeng; Jonathan E Pottle; Kevin Lee; Alun R Wang; Stephenie G Yi; Jennifer A S Scruggs; Suresh S Sikka; Ming Li

    2008-01-01

    Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells,free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear;however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers.

  16. An ex situ study of the adsorption of calcium phosphate from solution onto TiO2(110) and Al2O3(0001)

    Science.gov (United States)

    Murphy, M.; Walczak, M. S.; Hussain, H.; Acres, M. J.; Muryn, C. A.; Thomas, A. G.; Silikas, N.; Lindsay, R.

    2016-04-01

    Ex situ atomic force microscopy and x-ray photoelectron spectroscopy are employed to characterise the adsorption of calcium phosphate from an aqueous solution of CaCl2.H2O and KH2PO4 onto rutile-TiO2(110) and α-Al2O3(0001). Prior to immersion, the substrates underwent wet chemical preparation to produce well-defined surfaces. Calcium phosphate adsorption is observed on both rutile-TiO2(110) and α-Al2O3(0001), with atomic force microscopy images indicating island-type growth. In contrast to other studies on less well-defined TiO2 and Al2O3 substrates, the induction period for calcium phosphate nucleation appears to be comparable on these two surfaces.

  17. 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

  18. Dissolution kinetics of tuff rock and mechanism of chemical bond formation at the interface with cement grout

    International Nuclear Information System (INIS)

    The interaction of tuff rock and cement was studied to evaluate the effectiveness of sealing of tuff boreholes with cementitious grouts. Previous studies indicated chemical bond formation between tuff and cement. Dissolution studies were carried out on Topopah Spring member tuff and on tuff with cement. The results indicate the formation of calcium silicate and calcium aluminosilicate hydrates; phase identification is confirmed by XRD studies. The significance of the results obtained and their implications on properties of the interfacial region are included. 7 refs., 6 figs

  19. A novel biodegradable nicotinic acid/calcium phosphate composite coating on Mg–3Zn alloy

    International Nuclear Information System (INIS)

    A novel biodegradable composite coating is prepared to reduce the biodegradation rate of Mg–3Zn alloy. The Mg–3Zn substrate is first immersed into 0.02 mol L−1 nicotinic acid (NA) solution, named as vitamin B3, to obtain a pretreatment film, and then the electrodeposition of calcium phosphate coating with ultrasonic agitation is carried out on the NA pretreatment film to obtain a NA/calcium phosphate composite coating. Surface morphology is observed by scanning electron microscopy (SEM). Chemical composition is determined by X-ray diffraction (XRD) and EDX. Protection property of the coatings is evaluated by electrochemical tests. The biodegradable behavior is investigated by immersion tests. The results indicate that a thin but compact bottom layer can be obtained by NA pretreatment. The electrodeposition calcium phosphate coating consists of many flake particles and ultrasonic agitation can greatly improve the compactness of the coating. The composite coating is biodegradable and can reduce the biodegradation rate of Mg alloys in stimulated body fluid (SBF) for twenty times. The biodegradation process of the composite coating can be attributed to the gradual dissolution of the flake particles into chippings. - Highlights: ► NA/calcium phosphate composite coating is prepared to protect Mg–3Zn alloy implant. ► Nicotinic acid (vitamin B3) is available to obtain a protective bottom film. ► Ultrasonic agitation greatly improves the compactness of calcium phosphate coating. ► The composite coating can reduce the biodegradation rate of Mg–3Zn twenty times. ► The composite coating is biodegraded by the dissolution of flakes into chippings.

  20. A novel biodegradable nicotinic acid/calcium phosphate composite coating on Mg-3Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yingwei, E-mail: ywsong@imr.ac.cn; Shan, Dayong; Han, En-Hou

    2013-01-01

    A novel biodegradable composite coating is prepared to reduce the biodegradation rate of Mg-3Zn alloy. The Mg-3Zn substrate is first immersed into 0.02 mol L{sup -1} nicotinic acid (NA) solution, named as vitamin B{sub 3}, to obtain a pretreatment film, and then the electrodeposition of calcium phosphate coating with ultrasonic agitation is carried out on the NA pretreatment film to obtain a NA/calcium phosphate composite coating. Surface morphology is observed by scanning electron microscopy (SEM). Chemical composition is determined by X-ray diffraction (XRD) and EDX. Protection property of the coatings is evaluated by electrochemical tests. The biodegradable behavior is investigated by immersion tests. The results indicate that a thin but compact bottom layer can be obtained by NA pretreatment. The electrodeposition calcium phosphate coating consists of many flake particles and ultrasonic agitation can greatly improve the compactness of the coating. The composite coating is biodegradable and can reduce the biodegradation rate of Mg alloys in stimulated body fluid (SBF) for twenty times. The biodegradation process of the composite coating can be attributed to the gradual dissolution of the flake particles into chippings. - Highlights: Black-Right-Pointing-Pointer NA/calcium phosphate composite coating is prepared to protect Mg-3Zn alloy implant. Black-Right-Pointing-Pointer Nicotinic acid (vitamin B{sub 3}) is available to obtain a protective bottom film. Black-Right-Pointing-Pointer Ultrasonic agitation greatly improves the compactness of calcium phosphate coating. Black-Right-Pointing-Pointer The composite coating can reduce the biodegradation rate of Mg-3Zn twenty times. Black-Right-Pointing-Pointer The composite coating is biodegraded by the dissolution of flakes into chippings.

  1. 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...

  2. 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.

  3. 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....

  4. Plugging indicator

    International Nuclear Information System (INIS)

    It is often difficult to measure a plugging temperature when the impurity concentration in liquid sodium is low. Then, the plugging temperature is considered to be inferior to 1100C. Sometimes, a more precise indication is required. We propose a use for the plugging indicator which satisfies this type of requirement. A partial plugging of the indicator orifice is produced and increases at a constant temperature. A mathematical model describes this growth: it is based mainly on the kinetics of Na2O and NaH crystal growth and links the plugging time to oxygen or hydrogen concentrations. (orig.)

  5. Solar Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  6. A Simple Approach for an Eggshell-Based 3D-Printed Osteoinductive Multiphasic Calcium Phosphate Scaffold.

    Science.gov (United States)

    Dadhich, Prabhash; Das, Bodhisatwa; Pal, Pallabi; Srivas, Pavan K; Dutta, Joy; Ray, Sabyasachi; Dhara, Santanu

    2016-05-18

    Natural origin bioceramics are widely used for bone grafts. In the present study, an eggshell-derived bioceramic scaffold is fabricated by 3D printing as a potential bone-graft analogue. The eggshell, a biological waste material, was mixed with a specific ratio of phosphoric acid and chitosan to form a precursor toward the fabrication of an osteoinductive multiphasic calcium phosphate scaffold via a coagulation-assisted extrusion and sintering for a multiscalar hierarchical porous structure with improved mechanical properties. Physicochemical characterization of the formed scaffolds was carried out for phase analysis, surface morphology, and mechanical properties. A similar scaffold was prepared using a chemically synthesized calcium phosphate powder that was compared with the natural origin one. The higher surface area associated with the interconnected porosity along with multiple phases of the natural origin scaffold facilitated higher cell adhesion and proliferation compared to the chemically synthesized one. Further, the natural origin scaffold displayed relatively higher cell differentiation activity, as is evident by protein and gene expression studies. On subcutaneous implantation for 30 days, promising vascular tissue in-growth was observed, circumventing a major foreign body response. Collagen-rich vascular extracellular matrix deposition and osteocalcin secretion indicated bonelike tissue formation. Finally, the eggshell-derived multiphasic calcium phosphate scaffold displayed improvement in the mechanical properties with higher porosity and osteoinductivity compared to the chemically derived apatite and unveiled a new paradigm for utilization of biological wastes in bone-graft application. PMID:26853051

  7. Identification of CP12 as a Novel Calcium-Binding Protein in Chloroplasts

    Directory of Open Access Journals (Sweden)

    Agostinho Gomes Rocha

    2013-08-01

    Full Text Available Calcium plays an important role in the regulation of several chloroplast processes. However, very little is still understood about the calcium fluxes or calcium-binding proteins present in plastids. Indeed, classical EF-hand containing calcium-binding proteins appears to be mostly absent from plastids. In the present study we analyzed the stroma fraction of Arabidopsis chloroplasts for the presence of novel calcium-binding proteins using 2D-PAGE separation followed by calcium overlay assay. A small acidic protein was identified by mass spectrometry analyses as the chloroplast protein CP12 and the ability of CP12 to bind calcium was confirmed with recombinant proteins. CP12 plays an important role in the regulation of the Calvin-Benson-Bassham Cycle participating in the assembly of a supramolecular complex between phosphoribulokinase and glyceraldehyde 3-phosphate dehydrogenase, indicating that calcium signaling could play a role in regulating carbon fixation.

  8. Calcium-regulated in vivo protein phosphorylation in Zea mays L. root tips

    Science.gov (United States)

    Raghothama, K. G.; Reddy, A. S.; Friedmann, M.; Poovaiah, B. W.

    1987-01-01

    Calcium dependent protein phosphorylation was studied in corn (Zea mays L.) root tips. Prior to in vivo protein phosphorylation experiments, the effect of calcium, ethyleneglycol-bis-(beta-aminoethyl ether)-N-N' -tetraacetic acid (EGTA) and calcium ionophore (A-23187) on phosphorus uptake was studied. Calcium increased phosphorus uptake, whereas EGTA and A-23187 decreased it. Consequently, phosphorus concentration in the media was adjusted so as to attain similar uptake in different treatments. Phosphoproteins were analyzed by two-dimensional gel electrophoresis. Distinct changes in phosphorylation were observed following altered calcium levels. Calcium depletion in root tips with EGTA and A-23187 decreased protein phosphorylation. However, replenishment of calcium following EGTA and ionophore pretreatment enhanced phosphorylation of proteins. Preloading of the root tips with 32P in the presence of EGTA and A-23187 followed by a ten minute calcium treatment, resulted in increased phosphorylation indicating the involvement of calcium, calcium and calmodulin-dependent kinases. Calmodulin antagonist W-7 was effective in inhibiting calcium-promoted phosphorylation. These studies suggest a physiological role for calcium-dependent phosphorylation in calcium-mediated processes in plants.

  9. Circulating calcium concentrations, vascular disease and mortality: a systematic review.

    Science.gov (United States)

    Reid, I R; Gamble, G D; Bolland, M J

    2016-06-01

    Associations between serum calcium and vascular disease have been reported, but the consistency of these findings is unknown. We conducted a systematic review to determine whether circulating calcium concentrations are associated with risks of cardiovascular disease and death in normocalcaemic populations. We conducted PubMed searches up to 18 December 2014 and scrutinized reference lists of papers. Eligible studies related serum calcium to mortality or cardiovascular events in humans. A follow-up of at least one year was required for longitudinal studies. Studies in populations selected on the basis of renal disease or abnormal serum calcium were excluded. Two investigators performed independent data extraction. The results were tabulated and, where possible, meta-analysed. Five of 11 studies reported a statistically significant positive association between serum calcium and mortality. Meta-analysis of eight of these studies showed a hazard ratio of death of 1.13 (1.09, 1.18) per standard deviation of serum calcium. Eight of 13 studies reported a statistically significant positive association between serum calcium and cardiovascular disease. Meta-analysis of eight studies showed a hazard ratio of cardiovascular disease of 1.08 (1.04, 1.13) per standard deviation of serum calcium. For two studies reporting odds ratios, the pooled odds ratio per standard deviation was 1.22 (1.11, 1.32). When hazard ratios adjusted for cardiovascular risk factors were meta-analysed, the pooled hazard ratio was 1.04 (1.01, 1.08). Other studies demonstrated associations between serum calcium and stroke and between serum calcium and direct measurements of arterial disease and calcification. These observational data indicate that serum calcium is associated with vascular disease and death, but they cannot determine causality. PMID:26749423

  10. Concurrent imaging of synaptic vesicle recycling and calcium dynamics.

    Directory of Open Access Journals (Sweden)

    Haiyan eLi

    2011-11-01

    Full Text Available Synaptic transmission involves the calcium-dependent release of neurotransmitter from synaptic vesicles. Genetically encoded optical probes emitting different wavelengths of fluorescent light in response to neuronal activity offer a powerful approach to understand the spatial and temporal relationship of calcium dynamics to the release of neurotransmitter in defined neuronal populations. To simultaneously image synaptic vesicle recycling and changes in cytosolic calcium, we developed a red-shifted reporter of vesicle recycling based on a vesicular glutamate transporter, VGLUT1-mOrange2 (VGLUT1-mOr2, and a presynaptically-localized green calcium indicator, synaptophysin-GCaMP3 (SyGCaMP3 with a large dynamic range. The fluorescence of VGLUT1-mOr2 is quenched by the low pH of synaptic vesicles. Exocytosis upon electrical stimulation exposes the luminal mOr2 to the neutral extracellular pH and relieves fluorescence quenching. Re-acidification of the vesicle upon endocytosis again reduces fluorescence intensity. Changes in fluorescence intensity thus monitor synaptic vesicle exo- and endocytosis, as demonstrated previously for the green VGLUT1-pHluorin. To monitor changes in calcium, we fused the synaptic vesicle protein synaptophysin to the recently improved calcium indicator GCaMP3. SyGCaMP3 is targeted to presynaptic varicosities, and exhibits changes in fluorescence in response to electrical stimulation consistent with changes in calcium concentration. Using real-time imaging of both reporters expressed in the same synapses, we determine the time course of changes in VGLUT1 recycling in relation to changes in presynaptic calcium concentration. Inhibition of P/Q- and N-type calcium channels reduces calcium levels, as well as the rate of synaptic vesicle exocytosis and the fraction of vesicles released.

  11. Concurrent Imaging of Synaptic Vesicle Recycling and Calcium Dynamics

    Science.gov (United States)

    Li, Haiyan; Foss, Sarah M.; Dobryy, Yuriy L.; Park, C. Kevin; Hires, Samuel Andrew; Shaner, Nathan C.; Tsien, Roger Y.; Osborne, Leslie C.; Voglmaier, Susan M.

    2011-01-01

    Synaptic transmission involves the calcium dependent release of neurotransmitter from synaptic vesicles. Genetically encoded optical probes emitting different wavelengths of fluorescent light in response to neuronal activity offer a powerful approach to understand the spatial and temporal relationship of calcium dynamics to the release of neurotransmitter in defined neuronal populations. To simultaneously image synaptic vesicle recycling and changes in cytosolic calcium, we developed a red-shifted reporter of vesicle recycling based on a vesicular glutamate transporter, VGLUT1-mOrange2 (VGLUT1-mOr2), and a presynaptically localized green calcium indicator, synaptophysin-GCaMP3 (SyGCaMP3) with a large dynamic range. The fluorescence of VGLUT1-mOr2 is quenched by the low pH of synaptic vesicles. Exocytosis upon electrical stimulation exposes the luminal mOr2 to the neutral extracellular pH and relieves fluorescence quenching. Reacidification of the vesicle upon endocytosis again reduces fluorescence intensity. Changes in fluorescence intensity thus monitor synaptic vesicle exo- and endocytosis, as demonstrated previously for the green VGLUT1-pHluorin. To monitor changes in calcium, we fused the synaptic vesicle protein synaptophysin to the recently improved calcium indicator GCaMP3. SyGCaMP3 is targeted to presynaptic varicosities, and exhibits changes in fluorescence in response to electrical stimulation consistent with changes in calcium concentration. Using real time imaging of both reporters expressed in the same synapses, we determine the time course of changes in VGLUT1 recycling in relation to changes in presynaptic calcium concentration. Inhibition of P/Q- and N-type calcium channels reduces calcium levels, as well as the rate of synaptic vesicle exocytosis and the fraction of vesicles released. PMID:22065946

  12. Reduced levels of intracellular calcium releasing in spermatozoa from asthenozoospermic patients

    Directory of Open Access Journals (Sweden)

    García Juan F

    2009-02-01

    Full Text Available Abstract Background Asthenozoospermia is one of the most common findings present in infertile males characterized by reduced or absent sperm motility, but its aetiology remains unknown in most cases. In addition, calcium is one of the most important ions regulating sperm motility. In this study we have investigated the progesterone-evoked intracellular calcium signal in ejaculated spermatozoa from men with normospermia or asthenozoospermia. Methods Human ejaculates were obtained from healthy volunteers and asthenospermic men by masturbation after 4–5 days of abstinence. For determination of cytosolic free calcium concentration, spermatozoa were loaded with the fluorescent ratiometric calcium indicator Fura-2. Results Treatment of spermatozoa from normospermic men with 20 micromolar progesterone plus 1 micromolar thapsigargin in a calcium free medium induced a typical transient increase in cytosolic free calcium concentration due to calcium release from internal stores. Similar results were obtained when spermatozoa were stimulated with progesterone alone. Subsequent addition of calcium to the external medium evoked a sustained elevation in cytosolic free calcium concentration indicative of capacitative calcium entry. However, when progesterone plus thapsigargin were administered to spermatozoa from patients with asthenozoospermia, calcium signal and subsequent calcium entry was much smaller compared to normospermic patients. As expected, pretreatment of normospermic spermatozoa with both the anti-progesterone receptor c262 antibody and with progesterone receptor antagonist RU-38486 decreased the calcium release induced by progesterone. Treatment of spermatozoa with cytochalasin D or jasplakinolide decreased the calcium entry evoked by depletion of internal calcium stores in normospermic patients, whereas these treatments proved to be ineffective at modifying the calcium entry in patients with asthenozoospermia. Conclusion Our results suggest

  13. 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.

  14. Sustainability Indicators for Chemical Processes : I. Taxonomy

    Science.gov (United States)

    High demand and consumption rates of ecological materials and services to satisfy societal needs and for the dissipation of emissions are quickly exceeding the capacity that nature can provide. To avoid a tipping point situation, where ecological services may no longer be availa...

  15. Operational indicators

    International Nuclear Information System (INIS)

    The chapter presents the operational indicators related to budget, travel costs and tickets, the evolution of the annual program for regulatory inspection, the scientific production, requested patents and the numbers related to the production of the services offered by the Institution

  16. 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

  17. 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

  18. 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...

  19. 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.

  20. Calcium sulphate deposition on heated metal surfaces

    International Nuclear Information System (INIS)

    The accumulation of undesired matter at heat transfer surfaces (fouling) is a severe problem to industry. The growth of calcium sulphate dihydrate an heated metal surfaces has been examined and a mechanism for the effect of surface roughness on the amount of deposition has been proposed. A novel piece of equipment was designed and constructed in which the growth of crystals on heat transfer surfaces with different surface roughnesses could be observed under controlled solution conditions. The test section was a transparent rectangular channel into which three 25 mm diameter test pieces could be inserted such that the polished faces were planar with the rear face of the channel. The back faces of these test pieces were heated by contact with hot water. Using Reynolds numbers of 300 to 13,500 and calcium sulphate solutions with bulk concentrations from 20 to 50 mM Ca2+, no gross effect due to surface roughness was seen. However a limited effect, which distinguished grit-blasted surfaces from polished surfaces, was found in experiments with a bulk concentration from 28 to 33 mM Ca2+. In all of the experiments it was observed that the presence of bubbles enhanced crystal growth. It was also found that the amount of deposition formed on any surface decreased with decreasing dissolved oxygen content of the bulk solution. It is suggested that a bulk concentration of approximately 33 mM Ca2+ is a critical level of supersaturation, which corresponds with the so-called metastable limit of supersaturation. The surface roughness effect may be associated with two factors. Firstly, as the critical supersaturation is approached crystal growth is enhanced at certain sites, in particular the edges of bubbles. Secondly, very rough surfaces, such as grit-blasted surfaces, more readily support and initiate bubble formation and consequently the grit-blasted surface shows greater growth. Additional work with a different test rig, using a stagnant solution, indicated that suppression of

  1. 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.

  2. 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...

  3. Analytical and mechanical testing of high velocity oxy-fuel thermal sprayed and plasma sprayed calcium phosphate coatings.

    Science.gov (United States)

    Haman, J D; Chittur, K K; Crawmer, D E; Lucas, L C

    1999-01-01

    Plasma spraying (PS) is the most frequently used coating technique for implants; however, in other industries a cheaper, more efficient process, high-velocity oxy-fuel thermal spraying (HVOF), is in use. This process provides higher purity, denser, more adherent coatings than plasma spraying. The primary objective of this work was to determine if the use of HVOF could improve the mechanical properties of calcium phosphate coatings. Previous studies have shown that HVOF calcium phosphate coatings are more crystalline than plasma sprayed coatings. In addition, because the coatings are exposed to more complex loading profiles in vivo than standard ASTM tensile tests provide, a secondary objective of this study was to determine the applicability of four-point bend testing for these coatings. Coatings produced by HVOF and PS were analyzed by profilometry, diffuse reflectance Fourier transform infrared spectroscopy, X-ray diffraction, four-point bend, and ASTM C633 tensile testing. HVOF coatings were found to have lower amorphous calcium phosphate content, higher roughness values, and lower ASTM C633 bond strengths than PS coatings; however, both coatings had similar crystal unit cell sizes, phases present (including hydroxyapatite, beta-tricalcium phosphate, and tetracalcium phosphate), and four-point bend bond strengths. Thus, the chemical, structural, and mechanical results of this study, in general, indicate that the use of HVOF to produce calcium phosphate coatings is equivalent to those produced by plasma spraying. PMID:10556851

  4. Influence of calcium carbonate on extraction yield and quality of extra virgin oil from olive (Olea europaea L. cv. Coratina).

    Science.gov (United States)

    Squeo, G; Silletti, R; Summo, C; Paradiso, V M; Pasqualone, A; Caponio, F

    2016-10-15

    The aim of the research was to evaluate the effect of calcium carbonate (1%, 2%, and 4% of addition) at two different particle sizes (2.7μm and 5.7μm), added at the beginning of the malaxation phase, on both the extraction yield and the quality of oil obtained from Coratina olives at different ripening index. The results showed that calcium carbonate significantly increased the extraction yield of olive oil, more than affecting chemical indices. In particular, for less ripened olives, 1-2% of larger particle size calcium carbonate addiction determined a significant increase of the extraction effectiveness, ranging from 4.0 to 4.9%, while more ripened olives required higher amounts of coadjuvant (2-4% when using the larger particle size and 4% when using the smaller one), with a significant increase of the extraction yield up to 5%. Moreover, an increase of pungent perception was observed in some cases when adding calcium carbonate to more ripened olives. PMID:27173535

  5. 76 FR 81441 - Proposed Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2011-12-28

    ... chemical substances rutile, tin zinc, calcium-doped (CAS No. 389623-01- 2) and rutile, tin zinc, sodium... orders. The two chemical substances are identified as rutile, tin zinc, calcium-doped (PMN P-06-36; CAS..., tin zinc, calcium-doped and (P- 06-37) Rutile, tin zinc, sodium-doped. CAS numbers: (P-06-36)...

  6. The effect of calcium and chitosan metabolism to the excretion of radiostrontium in mice

    International Nuclear Information System (INIS)

    Chitosan, a natural nontoxic chelator, was reported to reduce whole body retention of radiostrontium in mice. As calcium has a similar chemical properties to strontium both of which be easily bound with hydroxyapatite structure, calcium can be either a competitor or enhancer to chitosan on the removal of radiostrontium. We compared the effect of chitosan and calcium on the excretion of ingested radiostrontium (85Sr). Chitosan or calcium(CaCl2) and usual food was mixed as 1:99 by weight. The mixed food to chitosan(group 1) or calcium(group 2) were given orally for 30 days before 85Sr administration. In other groups, mixed calcium and chitosan solution (group 3), 1% calcium (group 4), or 1% chitosan solution (group 5) was given for 7 days immediately after oral administration of 85SrCl2 (0.25μCi). In control group, no chitosan or calcium were given. Either chitosan or calcium was effective on the removal of 85Sr from mouse body (Table 1). Addition of calcium on chitosan did not improve or deteriorate the effect of chitosan on the removal of 85Sr from mouse body. In conclusion, calcium was similarly effective on the removal of 85Sr from mouse body. (author)

  7. Measuring corruption indicators and indices

    OpenAIRE

    MALITO, Debora Valentina

    2014-01-01

    This Working Paper is a background paper delivered to frame the workshop ‘Global Governance by Indicators: Measuring corruption and corruption indicators’ convened by the Global Governance Programme of the European University Institute in Florence on 17 and 18 October 2013. Successively it was developed further in EUI RSCAS WP 2014/37 - http://hdl.handle.net/1814/30582

  8. The pressure-induced calcium deposition on crosslinked polyurethanes.

    Science.gov (United States)

    Shunmugakumar, N; Jayabalan, M

    1992-06-01

    The pressure-induced calcium deposition in crosslinked polyurethane was studied. Two polyurethane systems, IPDI-PTMG/PPG-TMP and SMDI-PTMG/PPG-TMP were subjected to calcification under induced pressure. Calcium deposition in IPDI polymers was linear with the increase of soft segment (PTMG) content whereas in SMDI polymers the reverse trend was observed. Decreased phase mixing and hydrophilicity in the polymer (SMDI based) having increased soft segment content was attributed to the decreased calcification. The enhanced amount of calcium deposition under pressure indicates the possible influence of pressure on calcification. PMID:10078255

  9. Modification of oxygen and sulphur inclusions in steel by calcium treatment

    Directory of Open Access Journals (Sweden)

    T. Lis

    2009-04-01

    Full Text Available In the article, the results of examinations of changes in deformability of oxygen and sulphur inclusions in structural steel processed with calcium are discussed. The results obtained imply the positive influence of the calcium additives on the changes in geometry of oxygen and sulphur inclusions related to the modification of their chemical composition.

  10. 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...

  11. Regional distribution of calcium influx into bursting neurons detected with arsenazo III.

    OpenAIRE

    Graubard, K; Ross, W N

    1985-01-01

    Absorbance changes of the metallochromic indicator arsenazo III were used in conjunction with an array of 100 photodiodes to measure changes in intracellular calcium concentration at many positions simultaneously in identified neurons of the crab stomatogastric ganglion. When stimulated with intrasomatically injected current, several of these neurons showed calcium changes all over the cell, indicating that calcium channels were distributed widely in the neuropil and on the soma. When the mem...

  12. Cell response of calcium phosphate based ceramics, a bone substitute material

    Directory of Open Access Journals (Sweden)

    Juliana Marchi

    2013-01-01

    Full Text Available The aim of this study was to characterize calcium phosphate ceramics with different Ca/P ratios and evaluate cell response of these materials for use as a bone substitute. Bioceramics consisting of mixtures of hydroxyapatite (HAp and β-tricalcium phosphate (β-TCP powders in different proportions were pressed and sintered. The physical and chemical properties of these bioceramics were then characterized. Characterization of the biological properties of these materials was based on analysis of cell response using cultured fibroblasts. The number of cells attached to the samples was counted from SEM images of samples exposed to cell culture solution for different periods. These data were compared by analysis of variance (ANOVA complemented by the Tukey's test. The TCP sample had higher surface roughness and lower density. The adherence and growth of FMM1 cells on samples from all groups was studied. Even though the different calcium based ceramics exhibited properties which made them suitable as bone substitutes, those with higher levels of β-TCP revealed improved cell growth on their surfaces. These observations indicated two-phase calcium phosphate based materials with a β-TCP surface layer to be a promising bone substitute.

  13. Synthesis and characterization of calcium phosphate/collagen biocomposites doped with Zn{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maria Helena [Department of Dentistry, Federal University of Vales do Jequitinhonha e Mucuri-UFVJM, mailbox 38, Zip:39100-000, Diamantina, MG (Brazil)], E-mail: mariahelena.santos@gmail.com; Dias Heneine, Luis Guilherme [Department of Health Science, Ezequiel Dias Foundation, Belo Horizonte, MG (Brazil); Sander Mansur, Herman [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil)

    2008-05-01

    Composites were developed using calcium phosphate (CaP)/collagen (COL) doped with Zn{sup +2} to attempt the materials association with adequate properties for biological applications in the recovery of the bone tissue by trauma or pathogenies. Hydroxyapatite (HAP) and hydroxyapatite-{beta}tricalcium phosphate (HAP{beta}TCP) were synthesized and doped with zinc nitrate. High purity grade type I collagen was extracted and purified from bovine pericardium. CaP doped and undoped with Zn{sup +2} were produced with COL and the composites were developed using a simple mixture process. All samples were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction analysis (XRD. In addition, biocompatibility and cell viability were assessed by MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) using osteoblast cell culture. The results have indicated that both morphological and structural features and chemical composition of the composites were very similar to their precursors, collagen and calcium phosphate components. Also, the biocomposites presented a homogeneous aspect with the calcium phosphate particles aggregated to the collagen fibers. The biological evaluation of the composites in vitro showed cellular viability, presenting proliferation of the osteoblasts compared to the control cells (P < 0.05). The composites showed appropriate physical and biological properties creating more biologically active scaffolds that may support bone growth. Therefore, the novel developed biocomposites have high potential to be used for rebuilding small lesions in bone tissue engineering.

  14. The formation of calcium phosphate coatings by pulse laser deposition on the surface of polymeric ferroelectric

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Calcium phosphate coatings were obtained on ferroelectric polymer materials surface by using PLD method. • Obtained coatings have well-developed surface. • Depending on sputtering target composition it is possible to obtain crystalline or amorphous coating. • Formation of coating does not change the crystal structure of the ferroelectric polymer material. - Abstract: This work analyses the properties of calcium phosphate coatings obtained by pulsed laser deposition on the surface of the ferroelectric polymer material. Atomic force and scanning electron microscopy studies demonstrate that, regardless of the type of sputtering target, the calcium phosphate coatings have a multiscale rough surface that is potentially capable of promoting the attachment and proliferation of osteoblasts. This developed surface of the coatings is due to its formation mainly from a liquid phase. The chemical and crystalline composition of the coatings depends on the type of sputtering target used. It was shown that, regardless of the type of sputtering target, the crystalline structure of the ferroelectric polymer material does not change. Cell viability and adhesion studies of mesenchymal stromal cells on the coatings were conducted using flow cytometry and fluorescent microscopy. These studies indicated that the produced coatings are non-toxic

  15. Synthesis and characterization of calcium phosphate/collagen biocomposites doped with Zn2+

    International Nuclear Information System (INIS)

    Composites were developed using calcium phosphate (CaP)/collagen (COL) doped with Zn+2 to attempt the materials association with adequate properties for biological applications in the recovery of the bone tissue by trauma or pathogenies. Hydroxyapatite (HAP) and hydroxyapatite-βtricalcium phosphate (HAPβTCP) were synthesized and doped with zinc nitrate. High purity grade type I collagen was extracted and purified from bovine pericardium. CaP doped and undoped with Zn+2 were produced with COL and the composites were developed using a simple mixture process. All samples were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction analysis (XRD. In addition, biocompatibility and cell viability were assessed by MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) using osteoblast cell culture. The results have indicated that both morphological and structural features and chemical composition of the composites were very similar to their precursors, collagen and calcium phosphate components. Also, the biocomposites presented a homogeneous aspect with the calcium phosphate particles aggregated to the collagen fibers. The biological evaluation of the composites in vitro showed cellular viability, presenting proliferation of the osteoblasts compared to the control cells (P < 0.05). The composites showed appropriate physical and biological properties creating more biologically active scaffolds that may support bone growth. Therefore, the novel developed biocomposites have high potential to be used for rebuilding small lesions in bone tissue engineering

  16. The formation of calcium phosphate coatings by pulse laser deposition on the surface of polymeric ferroelectric

    Energy Technology Data Exchange (ETDEWEB)

    Bolbasov, E.N. [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation); Lapin, I.N.; Svetlichnyi, V.A. [Tomsk State University, 36 Lenin Avenue, Tomsk 634050 (Russian Federation); Lenivtseva, Y.D. [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation); Malashicheva, A. [Federal Almazov Medical Research Centre, 2 Akkuratova St., St. Petersburg 197341 (Russian Federation); St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034 (Russian Federation); ITMO University, Institute of translational Medicine, St. Petersburg (Russian Federation); Malashichev, Y. [St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034 (Russian Federation); Golovkin, A.S. [Federal Almazov Medical Research Centre, 2 Akkuratova St., St. Petersburg 197341 (Russian Federation); Anissimov, Y.G. [Griffith University, School of Natural Sciences, Engineering Dr., Southport, QLD 4222 (Australia); Tverdokhlebov, S.I., E-mail: tverd@tpu.ru [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation)

    2015-09-15

    Graphical abstract: - Highlights: • Calcium phosphate coatings were obtained on ferroelectric polymer materials surface by using PLD method. • Obtained coatings have well-developed surface. • Depending on sputtering target composition it is possible to obtain crystalline or amorphous coating. • Formation of coating does not change the crystal structure of the ferroelectric polymer material. - Abstract: This work analyses the properties of calcium phosphate coatings obtained by pulsed laser deposition on the surface of the ferroelectric polymer material. Atomic force and scanning electron microscopy studies demonstrate that, regardless of the type of sputtering target, the calcium phosphate coatings have a multiscale rough surface that is potentially capable of promoting the attachment and proliferation of osteoblasts. This developed surface of the coatings is due to its formation mainly from a liquid phase. The chemical and crystalline composition of the coatings depends on the type of sputtering target used. It was shown that, regardless of the type of sputtering target, the crystalline structure of the ferroelectric polymer material does not change. Cell viability and adhesion studies of mesenchymal stromal cells on the coatings were conducted using flow cytometry and fluorescent microscopy. These studies indicated that the produced coatings are non-toxic.

  17. Adherence and electrochemical behavior of calcium titanate coatings onto 304 stainless steel substrate

    International Nuclear Information System (INIS)

    Calcium titanate has been proposed as a coating for biomedical applications but it has not been reported characterization of adhesion failure mechanisms or electrochemical properties in time. In this work have been studied these properties of a calcium titanate coating growth onto AISI 304 steel deposited by r.f. magnetron sputtering. It was found that the coating has a critical adhesive load of 6.53 ± 0.14 N. With respect to its electrochemical properties potentiodynamic polarization curves show that the calcium titanate coating provides protection to AISI 304 steel. However. EIS indicates that even though metal dissolution occur through the pores in the coating, this leads to the precipitation of salts that block pores; this precipitates layer acts like and additional barrier to the metal dissolution in the system. The coatings deposition was carried out via magnetron sputtering during 4 hours at 500 grades C. The crystal structure of the films was determined by using glancing incident X-ray diffraction. The chemical composition of deposited films was performed by impedance dispersive X-ray spectroscopy (EDX) in the scanning electron microscopy (Jeol JSM-649 OLV Sem), and the grain size and the roughness was obtained using an atomic force microscopy from Asylum Research MFP-3D using a cantilever silicon tip in non-contact mode and calculated by scanning probe image processor. (Author)

  18. Adherence and electrochemical behavior of calcium titanate coatings onto 304 stainless steel substrate

    Energy Technology Data Exchange (ETDEWEB)

    Esguerra A, J.; Aguilar, Y. [Universidad del Valle, Escuela de Ingenieria de Materiales, TPMR, Calle 13 No. 100-00, A. A. 25360 Cali (Colombia); Aperador, W. [Escuela Colombiana de Ingenieria Julio Garavito, Escuela de Ingenieria Mecanica, AK 45 No. 205-59 (Autopista Norte), A. A. 14520 Bogota (Colombia); Alba de Sanchez, N. [Universidad Autonoma de Occidente, Grupo de Investigacion en Ciencia e Ingenieria de Materiales, Calle 25 No. 115-85, A. A. 2790 Cali (Colombia); Bolanos P, G.; Rincon, C., E-mail: johanna.esguerra@univalle.edu.co [Universidad del Cauca, Departamento de Fisica, Laboratorio de Fisica de Bajas Temperaturas, Calle 5 No. 4-70, A. A. 996 Popayan (Colombia)

    2014-07-01

    Calcium titanate has been proposed as a coating for biomedical applications but it has not been reported characterization of adhesion failure mechanisms or electrochemical properties in time. In this work have been studied these properties of a calcium titanate coating growth onto AISI 304 steel deposited by r.f. magnetron sputtering. It was found that the coating has a critical adhesive load of 6.53 ± 0.14 N. With respect to its electrochemical properties potentiodynamic polarization curves show that the calcium titanate coating provides protection to AISI 304 steel. However. EIS indicates that even though metal dissolution occur through the pores in the coating, this leads to the precipitation of salts that block pores; this precipitates layer acts like and additional barrier to the metal dissolution in the system. The coatings deposition was carried out via magnetron sputtering during 4 hours at 500 grades C. The crystal structure of the films was determined by using glancing incident X-ray diffraction. The chemical composition of deposited films was performed by impedance dispersive X-ray spectroscopy (EDX) in the scanning electron microscopy (Jeol JSM-649 OLV Sem), and the grain size and the roughness was obtained using an atomic force microscopy from Asylum Research MFP-3D using a cantilever silicon tip in non-contact mode and calculated by scanning probe image processor. (Author)

  19. Effect of calcium chloride and calcium lactate on quality and shelf-life of fresh-cut guava slices

    International Nuclear Information System (INIS)

    Present study was conducted to investigate the effectiveness of chemical treatments at low temperature on the quality of fresh-cut guava slices during 2011-12. Uniform sized guava slices were made free from seeds and treated with calcium chloride and calcium lactate with concentration 0.9%, 1.8%, 2.7% or 3.6%. After packing in plastic boxes, all treated samples were stored at 5 degree C + 2 degree C in a refrigerator for 24 days with 6 day interval between different removals. The results obtained from physico-chemical analysis showed decrease in firmness (111.67-12.67gf) and increase in browning (1.19-1.93nm) of guava slices compared to control with the passage of storage interval. Moreover, scores in taste (7.33-1.00), flavour (7.33-1.00), colour (7.50-1.00) and texture (7.67-1.00) of guava slices was also decreased with respect to interaction of treatments and storage period. Calcium chloride at the rate 2.7% showed significantly higher stability than other concentrations of calcium chloride and calcium lactate in delaying firmness and browning of fresh-cut guava slices along with maintaining their organoleptic properties for longer storage period. However, calcium chloride imparted undesirable bitterness to fresh-cut guava slices at the concentration of 3.6%. Based on the overall quality performance, 2.7% calcium chloride and 3.6% calcium lactate exhibited better results than other concentrations and control with storage life of 8 days at 5 degree C + 2 degree C. (author)

  20. Inotropic effect, binding properties, and calcium flux effects of the calcium channel agonist CGP 28392 in intact cultured embryonic chick ventricular cells

    International Nuclear Information System (INIS)

    CGP 28392 is a recently described dihydropyridine derivative with positive inotropic properties. To study the mechanism of action of this putative calcium channel agonist, we have related the effects of CGP 28392 on contraction (measured with an optical video system) and radioactive calcium uptake to ligand-binding studies in cultured, spontaneously beating chick embryo ventricular cells. CGP 28392 produced a concentration-dependent increase in amplitude and velocity of contraction (EC50 = 2 x 10(-7) M; maximum contractile effect = 85% of the calcium 3.6 mM response). Nifedipine produced a shift to the right of the concentration-effect curve for CGP 28392 without decreasing the maximum contractile response, suggesting competitive antagonism (pA2 = 8.3). Computer analysis of displacement of [3H]nitrendipine binding to intact heart cells by unlabeled CGP 28392 indicated a K /sub D/ = 2.2 +/- 0.95 x 10(-7) M, in good agreement with the EC50 for the inotropic effect. CGP 28392 increased the rate of radioactive calcium influx (+39% at 10 seconds) without altering beating rate, while nifedipine decreased radioactive calcium influx and antagonized the CGP 28392-induced increase in calcium influx. Our results indicate that, in intact cultured myocytes, CGP 28392 acts as a calcium channel agonist and competes for the dihydropyridine-binding site of the slow calcium channel. In contrast to calcium channel blockers, CGP 28392 increases calcium influx and enhances the contractile state

  1. Calcium Occupancy of N-terminal Sites within Calmodulin Induces Inhibition of the Ryanodine Receptor Calcium Release Channel

    Energy Technology Data Exchange (ETDEWEB)

    Boschek, Curt B; Jones, Terry E; Squier, Thomas C; Bigelow, Diana J

    2007-08-01

    Calmodulin (CaM) regulates calcium release from intracellular stores in skeletal muscle through its association with the ryanodine receptor (RyR1) calcium release channel, where CaM association enhances channel opening at resting calcium levels and its closing at micromolar calcium levels associated with muscle contraction. A high-affinity CaM-binding sequence (RyRp) has been identified in RyR1, which corresponds to a 30-residue sequence (i.e., K3614 – N3643) located within the central portion of the primary sequence. However, it is currently unclear whether the identified CaM-binding sequence a) senses calcium over the physiological range of calcium-concentrations associated with RyR1 regulation or b) plays a structural role unrelated to the calcium-dependent modulation of RyR1 function. Therefore, we have measured the calcium-dependent activation of the individual domains of CaM in association with RyRp and their relationship to the CaM-dependent regulation of RyR1. These measurements utilize an engineered CaM, permitting the site-specific incorporation of N-(1-pyrene) maleimide at either T34C (PyN-CaM) or T110C (PyC-CaM) in the N- and C-domains, respectively. Consistent with prior measurements, we observe a high-affinity association between both apo- and calcium-activated CaM and RyRp. Upon association with RyRp, fluorescence changes in PyN-CaM or PyC-CaM permit the measurement of the calcium-activation of these individual domains. Fluorescence changes upon calcium-activation of PyC-CaM in association with RyRp are indicative of high-affinity calcium-dependent activation of the C-terminal domain of CaM bound to RyRp at resting calcium levels and the activation of the N-terminal domain at levels of calcium associated cellular activation. In comparison, occupancy of calcium-binding sites in the N-domain of CaM mirrors the calcium-dependence of RyR1 inhibition observed at activating calcium levels, where [Ca]1/2 = 4.3 0.4 μM, suggesting a direct regulation of Ry

  2. Calcium metabolism in lithium-treated patients

    International Nuclear Information System (INIS)

    The bone mineral content (BMC) together with biochemical indices of calcium metabolism were measured in 83 manic-depressive patients on long-term lithium therapy. The patients were diagnosed and divided into a unipolar and a bipolar group according to strict symptomatic course criteria. The patients with bipolar course had a significantly decreased BMC (88% of normal, P < 0.001), while the unipolar patients had normal BMC. Both groups had biochemical changes consistent with primary hyperparathyroidism. (author)

  3. 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...

  4. X-Ray Diffraction Technique in the Analysis of Phases of Hydroxylapatite and Calcium Phosphate in a Human Jaw

    Directory of Open Access Journals (Sweden)

    Srđan D. Poštić

    2014-06-01

    Full Text Available Objective: Human jawbones consist mainly of hydroxylapatite. The aim of this study was to assess the structure of solid calcium phosphate compounds of the jawbone in cases of normal and osteoporotic JBs. Design: The X-ray diffraction technique was used to analyze the structure of samples of cadavers’ jawbones. The experimental JB samples were taken from an osteoporotic and atrophic jawbone, and control samples were from normal and nonosteoporotic bone samples. Results: Hydroxylapatite was the only phase in control bone samples. In experimental bone samples, the above-mentioned phase was registered, as well as monetite and brushite. Conclusion: The obtained data indicated that the changes of crystalographic forms of calcium phosphate in the physiologic system were balanced according to the possibility of change in the inorganic chemical system.

  5. Properties of the calcium-activated chloride current in heart

    OpenAIRE

    1992-01-01

    We used the whole cell patch clamp technique to study transient outward currents of single rabbit atrial cells. A large transient current, IA, was blocked by 4-aminopyridine (4AP) and/or by depolarized holding potentials. After block of IA, a smaller transient current remained. It was completely blocked by nisoldipine, cadmium, ryanodine, or caffeine, which indicates that all of the 4AP-resistant current is activated by the calcium transient that causes contraction. Neither calcium- activated...

  6. Cortical alveoli of Paramecium: a vast submembranous calcium storage compartment

    OpenAIRE

    1991-01-01

    The plasma membrane of Paramecium is underlain by a continuous layer of membrane vesicles known as cortical alveoli, whose function was unknown but whose organization had suggested some resemblance with muscle sarcoplasmic reticulum. The occurrence of antimonate precipitates within the alveoli first indicated to us that they may indeed correspond to a vast calcium storage site. To analyze the possible involvement of this compartment in calcium sequestration more directly, we have developed a ...

  7. Modulation of cytosolic-free calcium transients by changes in intracellular calcium-buffering capacity: correlation with exocytosis and O2-production in human neutrophils

    OpenAIRE

    1984-01-01

    The intracellularly trapped fluorescent calcium indicator, quin 2, was used not only to monitor changes in cytosolic-free calcium, [Ca2+]i, but also to assess the role of [Ca2+]i in neutrophil function. To increase cytosolic calcium buffering, human neutrophils were loaded with various quin 2 concentrations, and [Ca2+]i transients, granule content release as well as superoxide [O2-] production were measured in response to the chemotactic peptide formyl-methionyl-leucyl- phenylalanine (fMLP) a...

  8. Calcium Binding to Amino Acids and Small Glycine Peptides in Aqueous Solution: Toward Peptide Design for Better Calcium Bioavailability.

    Science.gov (United States)

    Tang, Ning; Skibsted, Leif H

    2016-06-01

    Deprotonation of amino acids as occurs during transfer from stomach to intestines during food digestion was found by comparison of complex formation constants as determined electrochemically for increasing pH to increase calcium binding (i) by a factor of around 6 for the neutral amino acids, (ii) by a factor of around 4 for anions of the acidic amino acids aspartic and glutamic acid, and (iii) by a factor of around 5.5 for basic amino acids. Optimized structures of the 1:1 complexes and ΔHbinding for calcium binding as calculated by density functional theory (DFT) confirmed in all complexes a stronger calcium binding and shorter calcium-oxygen bond length in the deprotonated form. In addition, the stronger calcium binding was also accompanied by a binding site shift from carboxylate binding to chelation by α-amino group and carboxylate oxygen for leucine, aspartate, glutamate, alanine, and asparagine. For binary amino acid mixtures, the calcium-binding constant was close to the predicted geometric mean of the individual amino acid binding constants indicating separate binding of calcium to two amino acids when present together in solution. At high pH, corresponding to conditions for calcium absorption, the binding affinity increased in the order Lys < Arg < Cys < Gln < Gly ∼ Ala < Asn < His < Leu < Glu< Asp. In a series of glycine peptides, calcium-binding affinity was found to increase in the order Gly-Leu ∼ Gly-Gly < Ala-Gly < Gly-His ∼ Gly-Lys-Gly < Glu-Cys-Gly < Gly-Glu, an ordering confirmed by DFT calculations for the dipeptides and which also accounted for large synergistic effects in calcium binding for up to 6 kJ/mol when compared to the corresponding amino acid mixtures. PMID:27159329

  9. Calcium dynamics and buffering in motoneurones of the mouse spinal cord.

    Science.gov (United States)

    Palecek, J; Lips, M B; Keller, B U

    1999-10-15

    1. A quantitative analysis of endogenous calcium homeostasis was performed on 65 motoneurones in slices of the lumbar spinal cord from 2- to 8-day-old mice by simultaneous patch-clamp and microfluorometric calcium measurements. 2. Somatic calcium concentrations were monitored with a temporal resolution in the millisecond time domain. Measurements were performed by using a monochromator for excitation and a photomultiplier detection system. 3. Somatic calcium signalling was investigated during defined voltage-clamp protocols. Calcium responses were observed for membrane depolarizations positive to -50 mV. A linear relation between depolarization time and free calcium concentrations ([Ca2+]i) indicated that voltage-dependent calcium influx dominated the response. 4. Endogenous calcium homeostasis was quantified by using the 'added buffer' approach. In the presence of fura-2 and mag-fura-5, calcium transients decayed according to a monoexponential function. Decay-time constants showed a linear dependence on dye concentration and the extrapolated constant in the absence of indicator dye was 371 +/- 120 ms (n = 13 cells, 21 C). 5. For moderate elevations (< 1 microM), recovery kinetics of depolarization-induced calcium transients were characterized by a calcium-independent, 'effective' extrusion rate gamma = 140 +/- 47 s-1 (n = 13 cells, 21 C). 6. The endogenous calcium binding ratio for fixed buffers in spinal motoneurones was kappaB' = 50 +/- 17 (n = 13 cells), indicating that less than 2 % of cytosolic calcium ions contributed to [Ca2+]i. 7. Endogenous binding ratios in spinal motoneurones were small compared to those found in hippocampal or cerebellar Purkinje neurones. From a functional perspective, they provided motoneurones with rapid dynamics of cytosolic [Ca2+]i for a given set of influx, extrusion and uptake mechanisms. 8. With respect to pathophysiological conditions, our measurements are in agreement with a model where the selective vulnerability of spinal

  10. 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.

  11. 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...

  12. 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...

  13. Indice d' évolution des coûts des installations industrielles chimiques et pétrochimiques en France Cost Variation Index for Chemical and Petrochemical Installations in France

    Directory of Open Access Journals (Sweden)

    Benchecroun N.

    2006-11-01

    Full Text Available Un indice de coût des installations chimiques et pétrochimiques pour la France avait été proposé par le Département Évaluation de I'IFP en 1984. La maintenance de celui-ci s'avérait difficile sans l'aide des moyens informatiques aujourd'hui disponibles. La mise à jour de cet indice (EVAL a été faite en y apportant une modification en ce qui concerne la base (1980 = 100 pour le mettre en conformité avec les recommendations de l'OCDE sur les séries statistiques. L'évolution des coûts reflétée par EVAL est comparée avec celle d'autres indices de coût d'installation, publics (PEI ou privés (BEICIP, ainsi qu'avec l'évolution des prix à la consommation. On note une bonne concordance avec l'indice BEICIP sur l'ensemble de la période (1975-1986 ainsi que le décrochement de l'évolution des coûts par rapport à celle des prix en 1982. La déviation présentée par l'indice PEI a conduit à bâtir un indice bicomposant (BIEVAL pour vérifier qu'un choix correct de la pondération main d'oeuvre/matériaux (67/33 ainsi que des séries d'indices élémentaires cohérentes permettaient de restituer une évolution comparable à celle donnée par les indices multicomposants. Le Département Evaluation de l'IFP dispose donc de deux indices quasi équivalents, EVAL et BIEVAL, l'avantage du second étant d'avoir un délai de réponse plus faible. Actuellement (décembre 1986, les dernières valeurs connues sont celles de juillet 1986 pour EVAL et d'octobre 1986 pour BIEVAL. A cost index for chemical and petrochemical installations in France was proposed by the IFP Process Evaluation Department in 1984, The maintenance of this index was difficult without the help of the computerized facilities now available. This index (EVAL has been updated with a change in the base (1980 = 100 to have it conform with OECD recommendations for statistical series. The variation in costs reflected by EVAL is compared with that of other public (PEI or private

  14. The effect of sourdough and calcium propionate on the microbial shelf-life of salt reduced bread.

    Science.gov (United States)

    Belz, Markus C E; Mairinger, Regina; Zannini, Emanuele; Ryan, Liam A M; Cashman, Kevin D; Arendt, Elke K

    2012-10-01

    The consumption of low-salt bread represents an efficient way to improve public health by decreasing cardiovascular health issues related to increased intakes of sodium chloride (NaCl). The reduction of NaCl influences the bread quality characteristics, in particular the shelf-life. Calcium propionate (CP) is commonly used in bread as an antifungal agent. Alternatively, sourdough can be used as a natural preservative. This work addresses the feasibility of NaCl reduction in wheat bread focussing on shelf-life and the compensation using sourdough as well as chemical preservatives. The impact of NaCl reduction and the addition of preservative agents in conjunction with different NaCl concentrations on the shelf-life of bread were tested under 'environmental' conditions in a bakery as well as using challenge tests against selected fungi. The challenge tests were performed using fungi commonly found in the bakery environment such as Penicillium expansum, Fusarium culmorum and Aspergillus niger. NaCl reduction decreased the shelf-life by 1-2 days. The addition of sourdough with antifungal activity prolonged the shelf-life to 12-14 days whereas the addition of 0.3 % calcium propionate prolonged the shelf-life to 10-12 days only. The fungal challenge tests revealed differences in the determined shelf-life between the different fungi based on their resistance. Similar antifungal performance was observed in sourdough breads and calcium propionate breads when tested against the different indicator moulds. The findings of this study indicate that addition of sourdough fermented using a specifically selected antifungal Lactobacillus amylovorus DSM 19280 can replace the chemical preservative calcium propionate addition and compensate for the reduced level and, therefore, guarantee the product safety of low-salt bread. PMID:22569634

  15. 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......

  16. Calcium phosphate ceramics in drug delivery

    Science.gov (United States)

    Bose, Susmita; Tarafder, Solaiman; Edgington, Joe; Bandyopadhyay, Amit

    2011-04-01

    Calcium phosphate (CaP) particulates, cements and scaffolds have attracted significant interest as drug delivery vehicles. CaP systems, including both hydroxyapaptite and tricalcium phosphates, possess variable stoichiometry, functionality and dissolution properties which make them suitable for cellular delivery. Their chemical similarity to bone and thus biocompatibility, as well as variable surface charge density contribute to their controlled release properties. Among specific research areas, nanoparticle size, morphology, surface area due to porosity, and chemistry controlled release kinetics are the most active. This article discusses CaP systems in their particulate, cements, and scaffold forms for drug, protein, and growth factor delivery toward orthopedic and dental applications.

  17. In vitro macrophage cytotoxicity of five calcium silicates.

    OpenAIRE

    Skaug, V; Davies, R.; Gylseth, B

    1984-01-01

    Five calcium silicate minerals (two naturally occurring and three synthetic compounds) with defined morphology and chemical composition were compared for their cytotoxic and lysosomal enzyme releasing effects on unstimulated mouse peritoneal macrophages in vitro. One synthetic material, a fibrous tobermorite, was cytotoxic towards the cells, and two naturally occurring wollastonites induced selective release of beta-glucuronidase from the cells.

  18. Mudanças fisiológicas e químicas em bananas 'Nanica' e 'Pacovan' tratadas com carbureto de cálcio Physiological and chemical changes in 'Nanica' and 'Pacovan' bananas treated with calcium carbide

    Directory of Open Access Journals (Sweden)

    Dijauma Honório Nogueira

    2007-01-01

    Full Text Available O objetivo deste trabalho foi avaliar mudanças fisiológicas e químicas em bananas 'Nanica' e 'Pacovan' tratadas com elevadas doses de carbureto de cálcio (CaC2, para geração de acetileno. Os frutos foram colhidos no estádio de maturação II (verdes com leves traços amarelos. As pencas foram acondicionadas em caixas de madeira (50 x 50 x 40 cm, revestidas internamente com papel alumínio, hermeticamente fechadas e tratadas com quatro doses de CaC2 (0; 15; 30 e 45 g.m-3 e (0; 7; 15 e 30 g.m-3 para 'Nanica' e 'Pacovan', respectivamente. Foi utilizado um delineamento inteiramente casualizado, em esquema fatorial 4 x 6 (4 doses e 6 períodos de avaliação, com três repetições. As características avaliadas foram: atividade respiratória, conteúdos de amido, açúcares redutores (AR e clorofila total, e evolução da coloração do fruto (escala de 1-7. O acetileno liberado do CaC2 resultou em aumento da taxa respiratória, degradação do amido e elevação dos teores de AR, degradação da clorofila e intensificação da coloração amarela, uniformizando o amadurecimento, sobretudo para a cultivar Pacovan.The aim of this work was to evaluate physiological changes in 'Nanica' and 'Pacovan' bananas treated with high doses of calcium carbide (CaC2 as a generator of acetylene. Fruits were harvested in the maturity stage II (green fruit with light yellow stains. Hands were placed into wood boxes (50 x 50 x 40 cm internally covered with foil paper, hermetically closed, and treated with 4 doses of calcium carbide (0, 15, 30 and 45 g. m-3 and (0, 7, 15 and 30 g. m-3 for 'Nanica' and 'Pacovan', respectively. It was utilized a completely randomized experimental design, 4 x 6 factorial scheme (4 doses and 6 evaluation periods. The characteristics evaluated were: respiratory activity, starch and reducing sugars (RS, total chlorophyll, and color evolution (1-7 scale. The acetylene released from CaC2 resulted in an increase of respiratory rate

  19. 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.

  20. A field method for the determination of calcium and magnesium in limestone and dolomite

    Science.gov (United States)

    Shapiro, Leonard; Brannock, Walter Wallace

    1957-01-01

    The method is an adaptation of a procedure described by Betz and Noll1 in 1950. Calcium and magnesium are determined by visual titration using Versene (disodium ethylenediamine tetraacetate) with Murexide (ammonium purpurate) as the indicator for calcium and Eriochrome Black T as the indicator for magnesium.

  1. Effect of Indole Butyric Acid on the Transportation of Stored Calcium in Malus hupehensis Rhed. Seedling

    Institute of Scientific and Technical Information of China (English)

    LI Jia; YANG Hong-qiang; YAN Tian-li; SHU Huai-rui

    2006-01-01

    Calcium (Ca) plays an important role in the metabolism of higher plants. Recently, research on Ca2+ in plants has been focused especially at the cellular and molecular levels. Uptake, transport, and distribution are also very important for Ca to accomplish its function at the whole-plant level. In this experiment, one-year-old apple seedlings (M. hupehensis Rehd.) were investigated to determine the distribution of stored Ca, the different forms of Ca, and Ca2+-ATPase activity after treatment with indole butyric acid (IBA). The results showed that the total Ca measured in mature leaves and Ca2+-ATPase activity in tender leaves were higher compared with those in the control (CK). Calcium nitrate and calcium chloride (ALe-Ca) and calcium phosphate and calcium carbonate (HAC-Ca) decreased in both mature leaves and shoots,whereas water-soluble calcium (H2O-Ca), calcium pectate (NaCl-Ca), and calcium oxalate (HCl-Ca) increased. The percentage of active calcium, calcium pectate, and water-soluble calcium increased, whereas the percentage of calcium phosphate and calcium carbonate decreased. When treated with IBA, calcium fractions and percentage of the different forms of Ca was enhanced in 40 part per million (ppm) IBA compared with 20 ppm IBA and water. The results indicated that IBA increased the percentage of both active calcium (NaCl-Ca and H2O-Ca) in tender shoots and boosted the transportation of stored Ca in plants. IBA promoted Ca2+-ATPase activity and Ca2+ uptake in tender shoots of M. hupehensis. It can improve the total Ca contents and the relative percentage of Ca.

  2. 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

  3. 13C nuclear magnetic resonance study of the complexation of calcium by taurine

    International Nuclear Information System (INIS)

    13C Nuclear magnetic resonance chemical shifts, 1J/sub c-c/ scalar coupling constants, spin-lattice relaxation times, and nuclear Overhauser effects were determined for taurine-[1, 2 13C] and a taurine-[1 13C] and taurine-[2 13C] mixture in the presence and absence of calcium. Comparison of taurine titration shifts to values for related compounds reveals some unusual electronic properties of the taurine molecule. Stability constants of 1:1 calcium complexes with taurine zwitterions and anions, as well as their 13C chemical shifts, were obtained by least squares analysis of titration curves measured in the presence of calcium. The stability constants of calcium-taurine complexes were significantly lower than previous values and led to estimates that only approximately one percent of intracellular calcium of mammalian myocardial cells would exist in a taurine complex

  4. 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.

  5. 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 ...

  6. 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 ...

  7. 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

  8. Effect of high dietary calcium on weight management in rats

    International Nuclear Information System (INIS)

    The present study was undertaken to find out a suitable dietary regime to maintain a lower prevalence of overweight or obesity by adjusting the diet components. Therefore, male Swiss albino rats were selected according to their ages and divided into two main groups, i.e., premature and mature groups. Each rat group was divided into 4 subgroups and each subgroup was fed on a diet of varied composition. Serum levels of lipids, calcium, phosphorous and testosterone were determined in addition to body weight measurement. The results indicate non-significant decrease of percentage of body weight gain in premature rats fed on high-calcium diets while significant decrease of percentage of body weight gain in mature rats fed on the same diet composition. The levels of serum HDL-C, LDL-C, triglycerides and testosterone were significantly decreased in premature rats fed high- calcium diets. In premature rats, only rat subgroup fed on high calcium from milk, showed a significant decrease in serum cholesterol levels. Calcium and phosphorus levels exhibited non- significant change between premature rats. In mature rats, LDL-C data demonstrate nonsignificant changes while cholesterol and triglyceride levels were significantly decreased in rats fed high -calcium diet compared to control. HDL-C level revealed a significant decrease in sera of mature rats fed on high calcium from milk. Serum testosterone levels were significantly decreased in mature rats fed low- fat diets or low fat diets supplemented with high- calcium level. In general, one would suggest to consume low fat diet (4%) supplemented with high calcium from dry skimmed milk fortified with hydroxyapatite as suitable dietary program to avoid overweight or obesity.

  9. Calcium regulates caveolin-1 expression at the transcriptional level

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiao-Yan; Huang, Cheng-Cheng; Kan, Qi-Ming [Laboratory of Tumor Biology and Glycobiology, Department of Life Sciences, Shenyang Pharmaceutical University, Shenyang 110016, People' s Republic of China (China); Li, Yan [Experimental Animal Center, Department of Life Sciences, Shenyang Pharmaceutical University, Shenyang 110016, People' s Republic of China (China); Liu, Dan; Zhang, Xue-Cheng [Laboratory of Tumor Biology and Glycobiology, Department of Life Sciences, Shenyang Pharmaceutical University, Shenyang 110016, People' s Republic of China (China); Sato, Toshinori [Department of Biosciences and Informatics, Keio University, Hiyoshi, Yokohama 223-8522 (Japan); Yamagata, Sadako [Laboratory of Tumor Biology and Glycobiology, Department of Life Sciences, Shenyang Pharmaceutical University, Shenyang 110016, People' s Republic of China (China); Yamagata, Tatsuya, E-mail: tcyamagata@gmail.com [Laboratory of Tumor Biology and Glycobiology, Department of Life Sciences, Shenyang Pharmaceutical University, Shenyang 110016, People' s Republic of China (China)

    2012-09-28

    Highlights: Black-Right-Pointing-Pointer Caveolin-1 expression is regulated by calcium signaling at the transcriptional level. Black-Right-Pointing-Pointer An inhibitor of or siRNA to L-type calcium channel suppressed caveolin-1 expression. Black-Right-Pointing-Pointer Cyclosporine A or an NFAT inhibitor markedly reduced caveolin-1 expression. Black-Right-Pointing-Pointer Caveolin-1 regulation by calcium signaling is observed in several mouse cell lines. -- Abstract: Caveolin-1, an indispensable component of caveolae serving as a transformation suppressor protein, is highly expressed in poorly metastatic mouse osteosarcoma FBJ-S1 cells while highly metastatic FBJ-LL cells express low levels of caveolin-1. Calcium concentration is higher in FBJ-S1 cells than in FBJ-LL cells; therefore, we investigated the possibility that calcium signaling positively regulates caveolin-1 in mouse FBJ-S1 cells. When cells were treated with the calcium channel blocker nifedipine, cyclosporin A (a calcineurin inhibitor), or INCA-6 (a nuclear factor of activated T-cells [NFAT] inhibitor), caveolin-1 expression at the mRNA and protein levels decreased. RNA silencing of voltage-dependent L-type calcium channel subunit alpha-1C resulted in suppression of caveolin-1 expression. This novel caveolin-1 regulation pathway was also identified in mouse NIH 3T3 cells and Lewis lung carcinoma cells. These results indicate that caveolin-1 is positively regulated at the transcriptional level through a novel calcium signaling pathway mediated by L-type calcium channel/Ca{sup 2+}/calcineurin/NFAT.

  10. Calmidazolium evokes high calcium fluctuations in Plasmodium falciparum.

    Science.gov (United States)

    Budu, Alexandre; Gomes, Mayrim M; Melo, Pollyana M; El Chamy Maluf, Sarah; Bagnaresi, Piero; Azevedo, Mauro F; Carmona, Adriana K; Gazarini, Marcos L

    2016-03-01

    Calcium and calmodulin (CaM) are important players in eukaryote cell signaling. In the present study, by using a knockin approach, we demonstrated the expression and localization of CaM in all erythrocytic stages of Plasmodium falciparum. Under extracellular Ca(2+)-free conditions, calmidazolium (CZ), a potent CaM inhibitor, promoted a transient cytosolic calcium ([Ca(2+)]cyt) increase in isolated trophozoites, indicating that CZ mobilizes intracellular sources of calcium. In the same extracellular Ca(2+)-free conditions, the [Ca(2+)]cyt rise elicited by CZ treatment was ~3.5 fold higher when the endoplasmic reticulum (ER) calcium store was previously depleted ruling out the mobilization of calcium from the ER by CZ. The effects of the Ca(2+)/H(+) ionophore ionomycin (ION) and the Na(+)/H(+) ionophore monensin (MON) suggest that the [Ca(2+)]cyt-increasing effect of CZ is driven by the removal of Ca(2+) from at least one Ca(2+)-CaM-related (CaMR) protein as well as by the mobilization of Ca(2+) from intracellular acidic calcium stores. Moreover, we showed that the mitochondrion participates in the sequestration of the cytosolic Ca(2+) elicited by CZ. Finally, the modulation of membrane Ca(2+) channels by CZ and thapsigargin (THG) was demonstrated. The opened channels were blocked by the unspecific calcium channel blocker Co(2+) but not by 2-APB (capacitative calcium entry inhibitor) or nifedipine (L-type Ca(2+) channel inhibitor). Taken together, the results suggested that one CaMR protein is an important modulator of calcium signaling and homeostasis during the Plasmodium intraerythrocytic cell cycle, working as a relevant intracellular Ca(2+) reservoir in the parasite. PMID:26689736

  11. Characterization of ionomycin as a calcium ionophore.

    Science.gov (United States)

    Liu, C; Hermann, T E

    1978-09-10

    The ionophorous properties of a new antibiotic, ionomycin, have been studied. It was found that the antibiotic is capable of extracting calcium ion from the bulk of an aqueous phase into an organic phase. The antibiotic also acts as a mobile ion carrier to transport the cation across a solvent barrier. The divalent cation selectivity order for ionomycin as determined by ion competition experiments was found to be: Ca greater than Mg greater than Sr = Ba, where the binding of strontium and barium by the antibiotic is insignificant. The antibiotic also binds La3+ to some extent, but its complexation with monovalent alkali metal ions is negligible. Measurement of the binding of ionomycin with Ca2+ indicates that ionomycin complexes and transports calcium ion in a one to one stoichiometry. PMID:28319

  12. Analysis of fish otoliths by electrothermal vaporization inductively coupled plasma mass spectrometry: aspects of precipitating otolith calcium with hydrofluoric acid for trace element determination.

    Science.gov (United States)

    Arslan, Zikri

    2005-03-15

    A method is developed for determination of trace elements, including Ag, As, Cd, Co, Cr, Cu, Mn, Ni, Se, Tl and Zn, in fish otoliths by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). Hydrofluoric acid was used to precipitate calcium resulting from acid dissolution of otolith calcium carbonate. Initial acidity of the sample solution influenced the precipitation efficiency of calcium fluoride. Up to 99.5% of Ca was precipitated in solutions that contained less than 2% (v/v) HNO(3). Recoveries of the elements obtained from spiked artificial otolith solutions were between 90 and 103%. Stabilization of the elements within the ETV cell was achieved with 0.3mug Pd/0.2mug Rh chemical modifier that also afforded optimum sensitivity for multielement determination. The method was validated by the analysis of a fish otolith reference material (CRM) of emperor snapper, and then applied to the determination of the trace elements in otoliths of several fish species captured in Raritan Bay, New Jersey. Results indicated that fish physiology and biological processes could influence the levels of Cu, Mn, Se and Zn in the otoliths of fish inhabiting a similar aqueous environment. Otolith concentrations of Cr and Ni did not show any significant differences among different species. Concentrations for Ag, As, Cd, Co and Tl were also not significantly different, but were very low indicating low affinity of otolith calcium carbonate to these elements. PMID:18969949

  13. 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...

  14. Functional separation of deep cytoplasmic calcium from subplasmalemmal space calcium in cultured human uterine smooth muscle cells.

    Science.gov (United States)

    Young, Roger C; Zhang, PeiSheng

    2004-07-01

    For smooth muscle, two important functions of free intracellular calcium (Ca(2+)(i)) are modulation of plasma membrane excitability properties and modulation of the contractile apparatus. As proposed by van Breemen, Ca(2+)(i) can be divided into the subplasmalemmal space (Ca(2+)(sps)) and the deep cytosol (Ca(2+)(d)) by the superficial calcium buffer barrier. Using these distinctions, Ca(2+)(sps) activates the large conductance calcium-activated potassium channel (BK), and Ca(2+)(d) binds calcium-dependent fluorescent probes in the cytoplasm. We present here combined fluorescence-patch clamp experiments designed to simultaneously assess Ca(2+)(d) and Ca(2+)(sps) in cultured human uterine smooth muscle cells. Open probabilities (P(o)) of the BK channel were measured using the cell-attached patch clamp technique. P(o) was used to approximate changes of [Ca(2+)(sps)]. Relative concentrations of Ca(2+)(d) were approximated by observing fluorescence of Calcium green-1 (F). Under control conditions, we found similar time courses for rises of P(o) and F following 10nM oxytocin (OT) addition. In parallel experiments, but with lanthanum (La(3+)) added to the bath to block transmembrane calcium flux, P(o) was only slightly affected, but F increases were delayed and blunted. These data paradoxically indicate that following OT stimulation, the primary source of calcium for Ca(2+)(sps) is internal stores, and calcium entry from the extracellular space is required to raise Ca(2+)(d). When cells were exposed to cyclopiazonic acid (CPA) to release SR calcium stores, P(o) increased slowly, then persisted at large values. The persistence of P(o) rises suggests that removal of calcium from the subplasmalemmal space is primarily via reuptake into the SR. In the presence of La(3+), OT-induced rises of F were slightly prolonged, suggesting that transmembrane calcium flux contributes to decreasing Ca(2+)(d), but is not the primary mechanism. In summary, these data demonstrate that Ca(2

  15. Effect of lactose on intestinal absorption of calcium

    International Nuclear Information System (INIS)

    Calcium absorption was immediately increased when lactose was administered in large amounts in the intestine of standard rats fed on a vitamin D diet. The same effect could be reproduced with lactulose, a glucid un-hydrolyzed by lactase and unabsorbed. The occurrence of a saturation process for high doses of calcium agrees with a biochemical process through a carrier; this process was not inhibited by actinomycin D, which does not agree with a 'de novo' synthesis of a calcium binding protein; yet activation of the preexisting protein cannot be excluded. The intestinal effect of lactose resulted in an inhibition of bone catabolism in the adult normocalcemic rat indicating a possible interference of thyrocalcitonin. Finally in the young rat, hypocalcemic by lack of vitamin D, on account of the lactose effect, calcium can be considered as a 'third messenger' in the chain of intracellular events between the interaction of the parathyroid hormone with the bone receptor and the expression of its activity. (author)

  16. Relation of urinary calcium and magnesium excretion to blood pressure

    DEFF Research Database (Denmark)

    Kesteloot, Hugo; Tzoulaki, Ioanna; Brown, Ian J;

    2011-01-01

    Data indicate an inverse association between dietary calcium and magnesium intakes and blood pressure (BP); however, much less is known about associations between urinary calcium and magnesium excretion and BP in general populations. The authors assessed the relation of BP to 24-hour excretion...... of calcium and magnesium in 2 cross-sectional studies. The International Study of Macro- and Micro-Nutrients and Blood Pressure (INTERMAP) comprised 4,679 persons aged 40-59 years from 17 population samples in China, Japan, the United Kingdom, and the United States, and the International Cooperative Study......) of higher urinary calcium excretion (associations were smaller for diastolic BP) in INTERMAP. Qualitatively similar associations were observed in INTERSALT analyses. Associations between magnesium excretion and BP were small and nonsignificant for most of the models examined. The present data suggest...

  17. Injectable bioactive calcium-magnesium phosphate cement for bone regeneration

    International Nuclear Information System (INIS)

    Novel injectable and degradable calcium-magnesium phosphate cement (CMPC) with rapid-setting characteristic was developed by the introduction of magnesium phosphate cement (MPC) into calcium phosphate cement (CPC). The calcium-magnesium phosphate cement prepared under the optimum P/L ratio exhibited good injectability and desired workability. It could set within 10 min at 37 0C in 100% relative humidity and the compressive strength could reach 47 MPa after setting for 48 h, indicating that the prepared cement has relatively high initial mechanical strength. The results of in vitro degradation experiments demonstrated the good degradability of the injectable CMPC, and its degradation rate occurred significantly faster than that of pure CPC in simulated body fluid (SBF) solution. It can be concluded that the novel injectable calcium-magnesium phosphate cement is highly promising for a wide variety of clinical applications, especially for the development of minimally invasive techniques.

  18. 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.

  19. Allopregnanolone-induced rise in intracellular calcium in embryonic hippocampal neurons parallels their proliferative potential

    Directory of Open Access Journals (Sweden)

    Brinton Roberta

    2008-12-01

    Full Text Available Abstract Background Factors that regulate intracellular calcium concentration are known to play a critical role in brain function and neural development, including neural plasticity and neurogenesis. We previously demonstrated that the neurosteroid allopregnanolone (APα; 5α-pregnan-3α-ol-20-one promotes neural progenitor proliferation in vitro in cultures of rodent hippocampal and human cortical neural progenitors, and in vivo in triple transgenic Alzheimer's disease mice dentate gyrus. We also found that APα-induced proliferation of neural progenitors is abolished by a calcium channel blocker, nifedipine, indicating a calcium dependent mechanism for the proliferation. Methods In the present study, we investigated the effect of APα on the regulation of intracellular calcium concentration in E18 rat hippocampal neurons using ratiometric Fura2-AM imaging. Results Results indicate that APα rapidly increased intracellular calcium concentration in a dose-dependent and developmentally regulated manner, with an EC50 of 110 ± 15 nM and a maximal response occurring at three days in vitro. The stereoisomers 3β-hydroxy-5α-hydroxy-pregnan-20-one, and 3β-hydroxy-5β-hydroxy-pregnan-20-one, as well as progesterone, were without significant effect. APα-induced intracellular calcium concentration increase was not observed in calcium depleted medium and was blocked in the presence of the broad spectrum calcium channel blocker La3+, or the L-type calcium channel blocker nifedipine. Furthermore, the GABAA receptor blockers bicuculline and picrotoxin abolished APα-induced intracellular calcium concentration rise. Conclusion Collectively, these data indicate that APα promotes a rapid, dose-dependent, stereo-specific, and developmentally regulated increase of intracellular calcium concentration in rat embryonic hippocampal neurons via a mechanism that requires both the GABAA receptor and L-type calcium channel. These data suggest that AP

  20. Chemical composition of the essential oils of Citrus sinensis cv. valencia and a quantitative structure-retention relationship study for the prediction of retention indices by multiple linear regression

    Directory of Open Access Journals (Sweden)

    Larijani Kambiz

    2011-01-01

    Full Text Available The chemical composition of the volatile fraction obtained by head-space solid phase microextraction (HS-SPME, single drop microextraction (SDME and the essential oil obtained by cold-press from the peels of C. sinensis cv. valencia were analyzed employing gas chromatography-flame ionization detector (GC-FID and gas chromatography-mass spectrometry (GC-MS. The main components were limonene (61.34 %, 68.27 %, 90.50 %, myrcene (17.55 %, 12.35 %, 2.50 %, sabinene (6.50 %, 7.62 %, 0.5 % and α-pinene (0 %, 6.65 %, 1.4 % respectively obtained by HS-SPME, SDME and cold-press. Then a quantitative structure-retention relationship (QSRR study for the prediction of retention indices (RI of the compounds was developed by application of structural descriptors and the multiple linear regression (MLR method. Principal components analysis was used to select the training set. A simple model with low standard errors and high correlation coefficients was obtained. The results illustrated that linear techniques such as MLR combined with a successful variable selection procedure are capable of generating an efficient QSRR model for prediction of the retention indices of different compounds. This model, with high statistical significance (R2 train = 0.983, R2 test = 0.970, Q2 LOO = 0.962, Q2 LGO = 0.936, REP(% = 3.00, could be used adequately for the prediction and description of the retention indices of the volatile compounds.

  1. Application of Box-Behnken design to prepare gentamicin-loaded calcium carbonate nanoparticles.

    Science.gov (United States)

    Maleki Dizaj, Solmaz; Lotfipour, Farzaneh; Barzegar-Jalali, Mohammad; Zarrintan, Mohammad-Hossein; Adibkia, Khosro

    2016-09-01

    The aim of this research was to prepare and optimize calcium carbonate (CaCO3) nanoparticles as carriers for gentamicin sulfate. A chemical precipitation method was used to prepare the gentamicin sulfate-loaded CaCO3 nanoparticles. A 3-factor, 3-level Box-Behnken design was used for the optimization procedure, with the molar ratio of CaCl2: Na2CO3 (X1), the concentration of drug (X2), and the speed of homogenization (X3) as the independent variables. The particle size and entrapment efficiency were considered as response variables. Mathematical equations and response surface plots were used, along with the counter plots, to relate the dependent and independent variables. The results indicated that the speed of homogenization was the main variable contributing to particle size and entrapment efficiency. The combined effect of all three independent variables was also evaluated. Using the response optimization design, the optimized Xl-X3 levels were predicted. An optimized formulation was then prepared according to these levels, resulting in a particle size of 80.23 nm and an entrapment efficiency of 30.80%. It was concluded that the chemical precipitation technique, together with the Box-Behnken experimental design methodology, could be successfully used to optimize the formulation of drug-incorporated calcium carbonate nanoparticles. PMID:25950955

  2. Dairy meals of hospitalized children as a source of energy, calcium and phosphorus in satisfying their daily needs

    Directory of Open Access Journals (Sweden)

    Diana Vukman

    2016-07-01

    Full Text Available A dairy meal is defined as a specific food serving composed from milk and dairy products. Because of its nutritional value and complex chemical composition, milk and dairy products play an important role in the diet of children and represent a rich source of calcium, phosphorus, as well as valuable proteins, B vitamins and minerals. Healthy children should consume at least three servings of dairy products daily, which contributes to the total energy and nutrients that children need. The needs of an unhealthy child are often higher than those who are healthy and depend on the state of the body. The aim of this study was to determine the incidence of consumption of dairy meals in hospitalized children and to find out if their energy needs, as well as their need for calcium and phosphorus through the consumption of the same were met. Significant differences were found between recommended energy intake from dairy products and actual energy intake from consumed milk and dairy products in three Croatian regions (P=0.021 tested. The highest values were recorded in central Croatia (253 Kcal or 34.4 % and the lowest in the northern Croatian coastal region (17.05 Kcal or 20.1 %, which indicates a greater representation of milk and dairy meals in children’s daily menu. Furthermore, hospitalized children meet almost half of their recommended daily intake of calcium and phosphorus from dairy meals for all three regions. The highest rate was found in central Croatia, 48.7 % or 400 mg of calcium, respectively 42.9 % or 322.69 mg phosphorus, while the remaining portion of calcium and phosphorus originates from different rich non-dairy food sources. In all regions the most common forms of dairy foods consumed were milk and dairy desserts.

  3. Stability analysis for complexes in calcium-alkali bromide solutions

    International Nuclear Information System (INIS)

    We discuss the dependence of the stability of tetrahedral complexes in molten halide mixtures on the halogen species. This is done by calculating the equilibrium concentration of (CaBr4)2- complexes in calcium-alkali bromide solutions as a function of composition, in comparison with earlier calculations on the calcium-alkali chloride systems. The comparison supports a possible trend of increasing stability from chlorides to bromides, provided that halogen polarizability or chemical bonding contribute appreciably to the binding of a complex. Supporting evidence is noted and further experiments are suggested. (author). 10 refs, 2 figs

  4. Calcium-phosphate-osteopontin particles for caries control

    DEFF Research Database (Denmark)

    Schlafer, Sebastian

    Oftentimes caries lesions develop in protected sites that are difficult to access by self-performed mechanical tooth cleaning. At present, there is a growing interest in chemical adjuncts to mechanical procedures of oral hygiene that aim at biofilm control rather than biofilm eradication. Calcium...... drops to 6 or below and release buffering phosphate ions that stabilize biofilm pH above the critical level for enamel dissolution. With that twofold approach, calcium-phosphate-osteopontin particles may make a relevant contribution to clinical caries control....

  5. Determination of (210)Po in calcium supplements and the possible related dose assessment to the consumers.

    Science.gov (United States)

    Strumińska-Parulska, Dagmara I

    2015-12-01

    The aim of this pioneer study was to investigate the most popular calcium supplements as a potential additional source of polonium (210)Po in human diet. The analyzed calcium pharmaceutics contained organic or inorganic calcium compounds; some from natural sources as mussels' shells, fish extracts, or sedimentary rocks. The objectives of this research were to investigate the naturally occurring (210)Po activity concentrations in calcium supplements, find the correlations between (210)Po concentration in medicament and calcium chemical form, and calculate the effective radiation dose connected to analyzed calcium supplement consumption. As results showed, (210)Po concentrations in natural origin calcium supplements (especially sedimentary rocks) were higher than the other analyzed. Also the results of (210)Po analysis obtained for inorganic forms of calcium supplements were higher. The highest (210)Po activity concentrations were determined in mineral tablets made from sedimentary rocks: dolomite and chalk - 3.88 ± 0.22 and 3.36 ± 0.10 mBq g(-1) respectively; while the lowest in organic calcium compounds: calcium lactate and calcium gluconate - 0.07 ± 0.02 and 0.17 ± 0.01 mBq g(-1). The annual effective radiation doses from supplements intake were estimated as well. The highest annual radiation dose from (210)Po taken with 1 tablet of calcium supplement per day was connected to sample made from chalk - 2.5 ± 0.07 μSv year(-1), while the highest annual radiation dose from (210)Po taken with 1 g of pure calcium per day was connected to dolomite - 12.7 ± 0.70 μSv year(-1). PMID:26318774

  6. Calcium Carbonate Nucleation in an Alkaline Lake Surface Water, Pyramid Lake, Nevada, USA

    Science.gov (United States)

    Reddy, M.M.; Hoch, A.

    2012-01-01

    Calcium concentration and calcite supersaturation (??) needed for calcium carbonate nucleation and crystal growth in Pyramid Lake (PL) surface water were determined during August of 1997, 2000, and 2001. PL surface water has ?? values of 10-16. Notwithstanding high ??, calcium carbonate growth did not occur on aragonite single crystals suspended PL surface water for several months. However, calcium solution addition to PL surface-water samples caused reproducible calcium carbonate mineral nucleation and crystal growth. Mean PL surface-water calcium concentration at nucleation was 2.33 mM (n = 10), a value about nine times higher than the ambient PL surface-water calcium concentration (0.26 mM); mean ?? at nucleation (109 with a standard deviation of 8) is about eight times the PL surface-water ??. Calcium concentration and ?? regulated the calcium carbonate formation in PL nucleation experiments and surface water. Unfiltered samples nucleated at lower ?? than filtered samples. Calcium concentration and ?? at nucleation for experiments in the presence of added particles were within one standard deviation of the mean for all samples. Calcium carbonate formation rates followed a simple rate expression of the form, rate (mM/min) = A (??) + B. The best fit rate equation "Rate (?? mM/?? min) = -0.0026 ?? + 0.0175 (r = 0.904, n = 10)" was statistically significant at greater than the 0.01 confidence level and gives, after rearrangement, ?? at zero rate of 6.7. Nucleation in PL surface water and morphology of calcium carbonate particles formed in PL nucleation experiments and in PL surface-water samples suggest crystal growth inhibition by multiple substances present in PL surface water mediates PL calcium carbonate formation, but there is insufficient information to determine the chemical nature of all inhibitors. ?? 2011 U.S. Government.

  7. Osteoinduction of calcium phosphate biomaterials in small animals

    International Nuclear Information System (INIS)

    Although osteoinduction mechanism of calcium phosphate (CP) ceramics is still unclear, several essential properties have been reported, such as chemical composition, pore size and porosity, etc. In this study, calcium phosphate powder (Ca3(PO4)2, CaP, group 1), biphasic calcium phosphate ceramic powder (BCP, group 2), and intact BCP rods (group 3) were implanted into leg muscles of mice and dorsal muscles of rabbits. One month and three months after implantation, samples were harvested for biological and histological analysis. New bone tissues were observed in 10/10 samples in group 1, 3/10 samples in group 2, and 9/10 samples in group 3 at 3rd month in mice, but not in rabbits. In vitro, human mesenchymal stem cells (hMSCs) were cultured with trace CaP and BCP powder, and osteogenic differentiation was observed at day 7. Our results suggested that chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation. - Highlights: ► Intrinsic osteoinduction of calcium phosphate biomaterials was observed implanted in muscles of mice. ► Biomaterials powder also has osteoinduction property. ► Osteogenic genes and protein could be detected by RT-PCR and Western blot in implanted biomaterials. ► Osteogenic phenomenon could be observed by electron microscopy. ► The chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation

  8. 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

  9. Physiological response and quality attributes of peach fruit cv florida king as affected by different treatments of calcium chloride, putrescine and salicylic acid

    International Nuclear Information System (INIS)

    Despite the ample increase in peach growing area, improvement in quality and average yield is still negligible. The influence of foliar application of calcium chloride (CaCl/sub 2/), putrescine (PUT) and salicylic acid (SA) on fruit yield and physico-chemical characteristics of 'Florida King' peach cultivar was evaluated for two consecutive years (2011 and 2012). Results indicated that, application of CaCl/sub 2/ (1%), PUT (1, 2 and 3 mM) and SA (2 and 3 mM) increased fruit weight , fruit diameter, pulp: stone ratio and yield compared to control. In addition, fruit harvested from these growth elicitors treated trees did not show significant difference in total soluble solids and total sugar contents. All treatments resulted in higher fruit firmness, acidity and ascorbic acid contents than control. Higher calcium treatments proved toxic and significantly increased the calcium level in leaves and fruit. From present work it can be referred that spraying of CaCl/sub 2/, PUT and SA, significantly affected yield, and physico-chemical characteristics of peach cv. 'Florida King'. These growth elicitors are considered safe chemicals and can be applied to enhance production and improve fruit quality of peach without compromising the food safety standards. (author)

  10. 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.

  11. Putative nanobacteria represent physiological remnants and culture by-products of normal calcium homeostasis.

    Directory of Open Access Journals (Sweden)

    John D Young

    Full Text Available Putative living entities called nanobacteria (NB are unusual for their small sizes (50-500 nm, pleomorphic nature, and accumulation of hydroxyapatite (HAP, and have been implicated in numerous diseases involving extraskeletal calcification. By adding precipitating ions to cell culture medium containing serum, mineral nanoparticles are generated that are morphologically and chemically identical to the so-called NB. These nanoparticles are shown here to be formed of amorphous mineral complexes containing calcium as well as other ions like carbonate, which then rapidly acquire phosphate, forming HAP. The main constituent proteins of serum-derived NB are albumin, fetuin-A, and apolipoprotein A1, but their involvement appears circumstantial since so-called NB from different body fluids harbor other proteins. Accordingly, by passage through various culture media, the protein composition of these particles can be modulated. Immunoblotting experiments reveal that antibodies deemed specific for NB react in fact with either albumin, fetuin-A, or both, indicating that previous studies using these reagents may have detected these serum proteins from the same as well as different species, with human tissue nanoparticles presumably absorbing bovine serum antigens from the culture medium. Both fetal bovine serum and human serum, used earlier by other investigators as sources of NB, paradoxically inhibit the formation of these entities, and this inhibition is trypsin-sensitive, indicating a role for proteins in this inhibitory process. Fetuin-A, and to a lesser degree albumin, inhibit nanoparticle formation, an inhibition that is overcome with time, ending with formation of the so-called NB. Together, these data demonstrate that NB are most likely formed by calcium or apatite crystallization inhibitors that are somehow overwhelmed by excess calcium or calcium phosphate found in culture medium or in body fluids, thereby becoming seeds for calcification. The

  12. Intracellular pH changes induced by calcium influx during electrical activity in molluscan neurons

    OpenAIRE

    1980-01-01

    Simultaneous measurements of electrical activity and light absorbance have been made on nerve cell bodies from Archidoris monteryensis injected with indicator dyes. pH indicators, phenol red and bromocresol purple, and arsenazo III, which under normal conditions is primarily a calcium indicator have been employed. Voltage clamp pulses which induced calcium influx caused an absorbance decrease of the pH dyes indicating an internal acidification. The onset of the pH drop lagged the onset of Ca2...

  13. [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

  14. Chemical processes of coal for use in power plants. Part 1: Approximate analysis and associated indexes of pulverized coal; Procesos quimicos del carbon para su uso en centrales termoelectricas. Parte 1: Analisis aproximado e indices asociados del carbon pulverizado

    Energy Technology Data Exchange (ETDEWEB)

    Altamirano-Bedolla, J. A.; Manzanares-Papayanopoulos, E.; Herrera-Velarde, J. R. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: emp@iie.org.mx

    2010-11-15

    The usage of hydrocarbons, such as natural gas, oil products and coal, will be the main source of energy to the mankind for next generations. Therefore, the actual research and technological developments point out to employ with high efficiency those fuels. The main interests are to release most of the energy as possible and to guide the combustion reactions. It is well known that during the combustion process of coal, the chemical energy is converted to thermal energy, which it allows the steam production, and therefore to produce energy through an electric generator. The main interest of the work presented here is to study the behavior of the coal combustion processes in function of the approximate analysis and some associate indices of that analysis, to point out the optimization of the coal usage as main fuel in electrical power generation plants. [Spanish] El uso de hidrocarburos como son el gas natural, los derivados del petroleo y el carbon mineral, continuara siendo en las proximas decadas la principal fuente de energia de la humanidad. Por consiguiente, la investigacion cientifica y los desarrollos tecnologicos actualmente se enfocan en emplear de manera mas eficiente dichos combustibles, satisfaciendo entre otros factores, dos intereses principales: liberar la mayor cantidad de energia, reduciendo al minimo el material combustible no quemado, y direccionar las reacciones del proceso de combustion para minimizar la cantidad de productos no deseados resultantes de la reaccion. A traves de los procesos quimicos de combustion del carbon, se transforma la energia quimica a energia termica, lo que permite la produccion de vapor para a su vez impulsar una turbina la cual esta acoplada a un generador electrico. El objetivo del presente trabajo es el estudio del comportamiento de los procesos quimicos que se llevan a cabo durante las reacciones de combus-tion del carbon en funcion del analisis aproximado y de los indices asociados resultantes de dicho analisis; lo

  15. The use of leaves and roots of Laurus novocanariensis as an indicator for soil and rock chemical composition in the environment of a subtropical cloud forest (Tenerife, Canary Islands, Spain).

    Science.gov (United States)

    Heidak, M.; Glasmacher, U. A.; Schöler, H. F.; Hernández-Moreno, J. M.

    2012-04-01

    On the Canary Island of Tenerife exists a sensitive and endangered ecosystem called "laurel forest". Laurel forest is an endemic type of a humid subtropical forest and it still covers a terrain of roughly 60 km2 on Tenerife (nearly 7% of the territory) (FERNANDEZ et al. 2001). The existing Laurel forest soils have been developed on different rocks. Corresponding to different moisture regimes, Vertisols, Alfisols, Ultisols, and Inceptisols are developed on basaltic lava flows. Inceptisols, allophanic Andisols, and vitric Andisols are present on pyroclastic rocks (ARNALDS et al., 2007). Three volcanic rock types of the basanite-phonolite assemblage are recognised (Rothe, 2008): Basic (basanites, ankaramites), intermediate (trachybasanites, plagioclase phonolites), and salic (trachyte, trachyphonolite, phonolite). Trachytes (sensu stricto) are comparatively rare. The present study aims to understand the element cycle and feed back mechanism between volcanic rocks, soils, roots, and leaves. Laurus novocanariensis stands as a key example how leaves and roots in a subtropical cloud forest, such as on Canary Islands, can be used as an indicator for soil and rock geochemistry. To obtain a wide spectrum of inorganic elements, we chose for our samples a combination of ICP-OES and ICP-MS. Our results show clearly that certain elements are enriched or depleted in leaves and roots. Other elements mirror the chemical composition of the soils and the volcanic rocks in great detail. This study indicates that Laurus novocanariensis can be used to trace the element distribution of certain elements from volcanic rocks thru soils to roots and leaves without a large disturbance of a sensitive ecosystem.

  16. 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.

  17. The effect of calcium hydroxide on the steroid component of Ledermix® and Odontopaste®

    OpenAIRE

    Athanassiadis, M; Jacobsen, N.; Parashos, P

    2011-01-01

    Aim To investigate the chemical interaction of calcium hydroxide with the corticosteroid triamcinolone acetonide in Ledermix® Paste and in Odontopaste®, a new steroid/antibiotic paste. Methodology Validated methods were developed to analyse the interaction of calcium hydroxide in two forms, Pulpdent® Paste and calcium hydroxide powder, with triamcinolone acetonide within Odontopaste® and Ledermix® Paste. High-performance liquid chromatography (HPLC) was used to analyse the mixed samples of th...

  18. Calcium status in premenopausal and post menopausal women

    International Nuclear Information System (INIS)

    Background: In postmenopausal women, the two major causes of bone loss are oestrogen deficiency after menopause and age related processes. Bone turnover increases to high levels and oestrogen deficiency may induce calcium loss by indirect effects on extra skeletal calcium homeostasis. Objective of this study was to evaluate calcium status in pre-menopausal and postmenopausal women. Methods: This cross sectional study was carried out in 34 premenopausal women and 33 postmenopausal women, in Department of Physiology, Services Institute of Medical Sciences, Lahore. Height and weight of each woman were taken to find out the body mass index (BMI). Serum calcium, parathyroid hormone and calcitonin levels of each subject were determined. Results: Premenopausal women were obese (BMI>30 Kg/m/sup 2/) while postmenopausal women were overweight (BMI>25 Kg/m/sup 2/). Serum calcium levels were significantly lower in postmenopausal women than in pre-menopausal women, while serum parathyroid hormone levels were significantly higher in postmenopausal woman. Serum calcitonin level was not significantly different in the two groups. Conclusion: Postmenopausal women are calcium deficient and have increased bone turnover as indicated by increased serum parathyroid hormone levels. (author)

  19. Fibroblast-Like Synoviocytes Induce Calcium Mineral Formation and Deposition

    Directory of Open Access Journals (Sweden)

    Yubo Sun

    2014-01-01

    Full Text Available Calcium crystals are present in the synovial fluid of 65%–100% patients with osteoarthritis (OA and 20%–39% patients with rheumatoid arthritis (RA. This study sought to investigate the role of fibroblast-like synoviocytes (FLSs in calcium mineral formation. We found that numerous genes classified in the biomineral formation process, including bone gamma-carboxyglutamate (gla protein/osteocalcin, runt-related transcription factor 2, ankylosis progressive homolog, and parathyroid hormone-like hormone, were differentially expressed in the OA and RA FLSs. Calcium deposits were detected in FLSs cultured in regular medium in the presence of ATP and FLSs cultured in chondrogenesis medium in the absence of ATP. More calcium minerals were deposited in the cultures of OA FLSs than in the cultures of RA FLSs. Examination of the micromass stained with nonaqueous alcoholic eosin indicated the presence of birefringent crystals. Phosphocitrate inhibited the OA FLSs-mediated calcium mineral deposition. These findings together suggest that OA FLSs are not passive bystanders but are active players in the pathological calcification process occurring in OA and that potential calcification stimuli for OA FLSs-mediated calcium deposition include ATP and certain unidentified differentiation-inducing factor(s. The OA FLSs-mediated pathological calcification process is a valid target for the development of disease-modifying drug for OA therapy.

  20. Some studies on calcium phosphate embedded in polyvinyl alcohol matrix before and after γ-irradiation

    International Nuclear Information System (INIS)

    The Ca-P ratio in polymer matrix was adjusted to 1.67 as in hydroxyapatite. The complexed polyvinyl alcohol (PVA) materials exhibit the characteristic absorption bands of phosphate at 601 and 962 cm-1 indicating the presence of (HPO4)-1 anions in the structure. The X-ray diffraction (XRD) revealed that the reaction between Ca and P ions in the PVA medium has a great effect on polymeric matrix crystallization. After irradiation, XRD results for sample c showed more sharp peaks indicating that irradiation can break the principal chemical bonds and favoring additional crystallization processes and therefore the crystallinity increases. An improvement in the thermal stability of PVA doped with calcium phosphate could be seen with the increase of calcium phosphate intercalated with PVA. The surfaces of films were analyzed by scanning electron microscope (SEM) before and after γ-irradiation. The formation of hydroxyapatite is confirmed by energy dispersive X-ray spectroscopy (EDX analysis). The electric conduction data were interpreted on the basis of an intrachain one-dimensional interpolaron hopping model of Kuivalainen.

  1. Study on the complexation of humic substances with calcium ion by ion selective electrode method

    International Nuclear Information System (INIS)

    Introduction: Humic substances (HS), which are one of main organic components in soil and aquatic environment, can influence the migration and fate of nuclides through formation of complexes. To quantitatively describe such complex formation, it is essential to consider the formation of major dissolved constituents ions, such as alkali or alkali earth ions, with HSUI. This paper reports the result on the study of the complex formation of calcium ion with soil HS and polyacrylic acid, where polyacrylic acid is selected to observed the effect of heterogeneous composition of HS. Experimental: As an initial solution for the titration experiment, the fixed amounts of calcium ion, NaNO3 solution and HS or PAA were mixed in a 150 mL plastic bottle, which was covered with Laboatory Film (Parafilm 'M'). Then, a fixed amount of NaOH solution was added step by step and the concentration of calcium ion and pH in solution were measured (IM-40S ion meter, DKK.TOA CORP. Japan) simultaneously after each addition. All the experiments were conducted in the 0.01 mol/L NaNO3 solution at 298.2 K in temperature under Ar atmosphere. The humic substances, Elliott soil humic acid (HA) (Cat.No.1sl02H) and Elliott soil Fulvic acid (FA) (Cat.No. lsl02H ), were obtained from International Humic Substances Society(IHSS). Polyacrylic acids (PAA) were obtained from polyscience Inc.(M.W. ca. 450.000). The other chemicals are of analytical grade. De-ionized water (Milli-Q Pureline, Yamato, Japan) was used to prepare the solution. Results and discussion: Fig. 1. shows tile typical titration curves of 500 mg/L HA containing 0.00, 6.24, 20.4, 41.6 mg/L total calcium ion in 0.010 mol/L NaN3 at 298.2 K under Ar atmosphere. The differences between the titration curves of the solution with and without calcium ion indicate the formation of complex with HA. Fig. 1 also shows the plots of the concentration of free calcium ion versus the amounts of added NaOH obtained from the titration of the solution with

  2. 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...

  3. Monitoring of intracellular free calcium in perfused rat liver.

    Science.gov (United States)

    Ruttner, Z; Ligeti, L; Reinlib, L; Hines, K; McLaughlin, A C

    1993-06-01

    Fluorescent calcium indicators have been widely used to assess cytoplasmic calcium concentration in cells. To examine the role of calcium ions on different physiological functions (e.g. in case of liver; bile secretion, glucose metabolism, etc.) there is a need for whole organ studies. We have developed a technique to estimate intracellular free calcium changes in perfused rat liver. Krebs-Henseleit perfused livers were loaded with 7 microM or 35 microM Indo-1/AM. An area 3 mm in diameter and approximately 300 microns in depth was illuminated at 340 nm. Fluorescence was monitored with photomultiplier tubes at 3 wavelengths (400 nm for Ca-bound dye, 504 nm for free dye and 464 nm for NADH). The viability of liver preparations was assessed by measurement of the concentrations of lactate dehydrogenase and alanine aminotransferase in the effluent. Loading of the livers with 7 microM Indo-1/AM via the portal vein resulted in a 5-fold increase of fluorescence at 400 nm. However the dye 'leaked' out of the liver with a half-time of 18 min. Probenecid (a specific anion carrier blocker) inhibited loss of dye in a dose dependent fashion (2.5-10 mM). Transient calcium elevations were observed in response to vasopressin (5-50 nM) at physiological levels, ethanol (0.3-0.8 M) and the calcium ionophore, ionomycin. Certain limitations were apparent with this approach: (1) it was necessary to use an anion carrier blocker to maintain a relatively steady dye concentration; (2) endogenous NADH fluorescence interfered with the calcium signal; and (3) absolute values of calcium concentration could not be determined. PMID:8358770

  4. Scientific Opinion on the Tolerable Upper Intake Level of calcium

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies

    2012-07-01

    Full Text Available

    Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to re-evaluate the safety in use of calcium. The Panel was requested to consider if the Tolerable Upper Intake Level (UL for calcium established by the SCF in 2003 (2,500 mg/day for adults, including pregnant and lactating women, which was based on different intervention studies of long duration in which total daily calcium intakes of 2,500 mg from both diet and supplements were tolerated without adverse effects, needed to be changed on the basis of new available evidence. A number of placebo controlled human intervention studies in adults published since then also showed that total daily calcium intakes of 2,500 mg from both diet and supplements are tolerated without adverse effects. The Panel considers that no relationship has been established between long-term calcium intakes from diet and supplements and increased risk of nephrolithiasis, cardiovascular disease or prostate cancer. No new data have become available which would require a revision of the UL for calcium for adults, including pregnant and lactating women, of 2,500 mg. No new data have become available which would allow the setting of a UL for infants, children or adolescents. Data from European populations indicate that intakes of calcium in high consumers among adult males can be close to the UL. Although available data do not allow the setting of a UL for infants, children or adolescents, no risk has been identified with highest current levels of calcium intake in these age groups.

  5. Adsorption of Potassium and Calcium Ions by Variable Charge Soils

    Institute of Scientific and Technical Information of China (English)

    LIHONG-YAN; JIGUO-LIANG

    1992-01-01

    Interactions of potassium and calcium ions with four typical variable charge soils in South China were examined by measuring pK-0.5pCa value with a potassium ion-selective electrode and a calcium ion-selective electrode,and pK value with a potassium ion-selective electrode.The results showed that adsorption of potassium and calcium ions increased with soil suspension pH,and the tendency of the pK-0.5pCa value changing with pH differed with respect to pH range and potassium to calcium ratio.Adsorption of equal amount of calcium and potassium ions led to release of an identical number of protons,suggesting similar adsorption characteristics of these two ions when adsorbed by variable charge soils.Compared with red soil,latosol and lateritic red soil had higher adsorption selectivities for calcium ion.The red soil had a greater affinity for potassium ion than that for calcium ion at low concentration,which seems to result from its possession of 2:1 type minerals,such as vermiculite and mica with a high affinity for potassium ion.The results indicated that adsorption of potassium and calcium ions by the variable charge soils was chiefly caused by the electrostatic attraction between the cations and the soil surfaces.Moreover,it was found that sulfate could affect the adsorption by changing soil surface properties and by forming ion-pair.

  6. Two Dimensional Finite Element Model to Study Calcium Distribution in Oocytes

    Science.gov (United States)

    Naik, Parvaiz Ahmad; Pardasani, Kamal Raj

    2015-06-01

    Cytosolic free calcium concentration is a key regulatory factor and perhaps the most widely used means of controlling cellular function. Calcium can enter cells through different pathways which are activated by specific stimuli including membrane depolarization, chemical signals and calcium depletion of intracellular stores. One of the important components of oocyte maturation is differentiation of the Ca2+ signaling machinery which is essential for egg activation after fertilization. Eggs acquire the ability to produce the fertilization-specific calcium signal during oocyte maturation. The calcium concentration patterns required during different stages of oocyte maturation are still not completely known. Also the mechanisms involved in calcium dynamics in oocyte cell are still not well understood. In view of above a two dimensional FEM model has been proposed to study calcium distribution in an oocyte cell. The parameters such as buffers, ryanodine receptor, SERCA pump and voltage gated calcium channel are incorporated in the model. Based on the biophysical conditions the initial and boundary conditions have been framed. The model is transformed into variational form and Ritz finite element method has been employed to obtain the solution. A program has been developed in MATLAB 7.10 for the entire problem and executed to obtain numerical results. The numerical results have been used to study the effect of buffers, RyR, SERCA pump and VGCC on calcium distribution in an oocyte cell.

  7. Calcium carbonate as a possible dosimeter for high irradiation doses

    International Nuclear Information System (INIS)

    The aim of this work is to analyze the interactions of 5 MeV electron beam radiation and a 290 MeV/u Carbon beam with calcium carbonate (powder) at 298 K and at different irradiation doses, for the potential use of calcium carbonate as a high-dose dosimeter. The irradiation doses with the electron beam were from 0.015 to 9 MGy, and with Carbon beam from 1.5 kGy to 8 kGy. High-energy radiation induces the formation of free radicals in solid calcium carbonate that can be detected and measured by electron paramagnetic resonance (EPR). An increase of the EPR response for some of the free radicals produced in the sample was observed as a function of the irradiation dose. These measurements are reproducible; the preparation of the sample is simple and inexpensive; and the signal is stable for several months. The response curves show that the dosimeter tends to saturate at 10 MGy. Based on these properties, we propose this chemical compound as a high-dose dosimeter, mainly for electron irradiation. - Highlights: • This work analyzed the interactions of 5 MeV electron beam radiation and a 290 MeV/u Carbon beam with calcium carbonate (powder) at 298 K and at different irradiation doses. • The main goal is to search the potential use of calcium carbonate as a high-dose dosimeter. • High-energy radiation induces the formation of free radicals in solid calcium carbonate that can be detected and measured by electron paramagnetic resonance (EPR). • An increase of the EPR response for some of the free radicals produced in the sample was observed as a function of the irradiation dose. • We propose this chemical compound as a high-dose dosimeter, mainly for electron irradiation

  8. Raloxifene neutralizes the adverse effects of glutamate on cultured neurons by regulation of calcium oscillations.

    Science.gov (United States)

    Zhou, Xiangyu; Yang, Zhendong; Han, Li; Li, Xiaoyong; Feng, Meina; Zhang, Teng; Luo, Hongbin; Zhu, Liping; Zhang, Jiwei; Zhang, Qi; Hu, Qinghua

    2015-10-01

    Calcium dyshomeostasis is an important pathology of memory impairment. However, the mechanism of how calcium dyshomeostasis impairs neurons has remained elusive. The aim of the present study was to reveal the influence of calcium dyshomeostasis on the expression of calcium memory‑associated proteins and the ability of raloxifene to neutralize the adverse effects of glutamate on cultured neurons by regulation of calcium oscillations. After neurons were treated with various concentrations of glutamate alone or with raloxifene, the expression of calcium memory‑associated proteins and the influence on calcium dyshomeostasis was assessed. The results indicated that glutamate regulated calcium oscillation waves and expression of calcium memory‑associated protein in a concentration‑dependent manner. Raloxifene increased the expression of these proteins as well as neuronal survival. It is therefore concluded that glutamate regulated calcium oscillations in a dose‑dependent manner, while raloxifene protected neurons from destruction through glutamate exposure and at the same time neutralized the decrease in expression of the memory‑associated proteins. PMID:26252350

  9. 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

  10. Synthesis and characterization of zirconium-doped calcium phosphate biomaterial

    International Nuclear Information System (INIS)

    A new synthesis route for the production of calcium phosphate biomaterial was developed by using organic di-(2-ethylhexyl) phosphoric acid (DEHPA) mixed with calcium hydroxide slurry. Unlike the conventional involving chemical precipitation process this new method involves a sol-gel process. Another advantage of this method is the starting material DEHPA can form strong bonding with many elements including zirconium and rare earths. This makes it suitable to be used as drug delivery material especially those involving bone related disease. It also improves the biomaterial strength with the presence of zirconium oxide phase. From XRD analysis, the result shows the present of HA, α-TCP and β-TCP. The addition of different rare elements on to the calcium phosphate will varies the amount of these three phases. SEM analysis was also performed to study the morphology of the calcium phosphate material. The presence of the rare earths on to the calcium phosphate was established by using the EDS technique. (Author)

  11. Calcium oxalate crystals in eucalypt ectomycorrhizae: morphochemical characterization.

    Science.gov (United States)

    Pylro, Victor Satler; de Freitas, André Luiz Moreira; Otoni, Wagner Campos; da Silva, Ivo Ribeiro; Borges, Arnaldo Chaer; Costa, Maurício Dutra

    2013-01-01

    Ectomycorrhizal fungi are ubiquitous in forest ecosystems, benefitting plants principally by increasing the uptake of water and nutrients such as calcium from the soil. Previous work has demonstrated accumulation of crystallites in eucalypt ectomycorrhizas, but detailed morphological and chemical characterization of these crystals has not been performed. In this work, cross sections of acetic acid-treated and cleared ectomycorrhizal fragments were visualized by polarized light microscopy to evaluate the location of crystals within cortical root cells. Ectomycorrhizal sections were also observed by scanning electron microscopy (SEM) coupled with energy dispersive x-ray (EDS) microprobe analysis. The predominant forms of crystals were crystal sand (granules) and concretions. Calcium, carbon and oxygen were detected by EDS as constituent elements and similar elemental profiles were observed between both crystal morphologies. All analyzed crystalline structures were characterized as calcium oxalate crystals. This is the first report of the stoichiometry and morphology of crystals occurring in eucalypt ectomycorrhizas in tropical soils. The data corroborates the role of ectomycorrhizae in the uptake and accumulation of calcium in the form of calcium oxalate crystals in hybrid eucalypt plants. PMID:23844062

  12. Calcium oxalate crystals in eucalypt ectomycorrhizae: morphochemical characterization.

    Directory of Open Access Journals (Sweden)

    Victor Satler Pylro

    Full Text Available Ectomycorrhizal fungi are ubiquitous in forest ecosystems, benefitting plants principally by increasing the uptake of water and nutrients such as calcium from the soil. Previous work has demonstrated accumulation of crystallites in eucalypt ectomycorrhizas, but detailed morphological and chemical characterization of these crystals has not been performed. In this work, cross sections of acetic acid-treated and cleared ectomycorrhizal fragments were visualized by polarized light microscopy to evaluate the location of crystals within cortical root cells. Ectomycorrhizal sections were also observed by scanning electron microscopy (SEM coupled with energy dispersive x-ray (EDS microprobe analysis. The predominant forms of crystals were crystal sand (granules and concretions. Calcium, carbon and oxygen were detected by EDS as constituent elements and similar elemental profiles were observed between both crystal morphologies. All analyzed crystalline structures were characterized as calcium oxalate crystals. This is the first report of the stoichiometry and morphology of crystals occurring in eucalypt ectomycorrhizas in tropical soils. The data corroborates the role of ectomycorrhizae in the uptake and accumulation of calcium in the form of calcium oxalate crystals in hybrid eucalypt plants.

  13. Investigation of calcium phosphate coatings for biomedical applications

    International Nuclear Information System (INIS)

    Calcium phosphate is the main constituent of our bone and tooth minerals. The use of this bioactive material for coating implant such as artificial joint prosthesis, therefore, can promote biological fixation and enhance biocompatibility. Our initial work has been focused on the evaluation of experimental conditions of coating preparation and the effects of post-deposition calcium phosphate coatings on stainless steel substrates. The coating layers were produced by the precipitation technique and coatings were carried out in sol-gel by the dipping method. For comparison purposes a wet method was used to obtain a fine calcium phosphate ceramic powder for fabrication of microcrystal suspension used as a coating material. Scanning electron microscopy (SEM), energy dispersive microanalysis (EDS), energy dispersive x-ray fluorescence (EDXRF) and x-ray diffraction (XRD) were used to characterise the morphology, chemical composition and structure of the coatings. The results showed that the dip coating of stainless steel substrates using viscous solutions lead to the formation of porous calcium phosphate layers. These results suggested that fabrication of bioactive calcium phosphate coatings using this route offers significant advantages over the currently used methods due to considerably lower temperature process involved and may produce better result for substrates with complex shapes

  14. Purification and partial characterization of a calcium-stimulated protease from the cyanobacterium, Anabaena variabilis.

    Science.gov (United States)

    Lockau, W; Massalsky, B; Dirmeier, A

    1988-03-01

    A calcium-stimulated protease was purified to apparent homogeneity from the heterocyst-forming cyanobacterium Anabaena variabilis ATCC 29413. As judged from experiments with inhibitors and chromogenic peptide substrates, the enzyme is a serine protease with a substrate specificity like trypsin. Its apparent relative molecular mass is 52,000. Calcium depletion inhibits the enzymic activity by 92%. Half-maximal activity requires about 0.5 microM free Ca2+. The enzyme binds to a hydrophobic column in a calcium-dependent manner, indicating calcium-induced exposure of a hydrophobic domain. The possible role of the protease in heterocyst differentiation is discussed. PMID:3127208

  15. Effect of high calcium concentration influents on enhanced biological phosphorus removal process

    International Nuclear Information System (INIS)

    In this work, the effect of calcium concentration in wastewater on the polyphosphate accumulating organisms (PAO) is investigated as well as its influence in PAO metabolism, specifically in the YPO4 (ratio between phosphorus release and acetic acid uptake). For this study a sequencing batch reactor (SBR) anaerobic-aerobic was used, in which the PAO enriched biomass was exposed to different calcium concentrations in the influent wastewater. The results indicate that until a given calcium level in the influent wastewater (35 mg Ca/l) the metabolism is not affect, but higher calcium concentrations lead to significant YPO4 decline. (Author) 18 refs.

  16. Targeted cellular ionic calcium chelation by oxalates: Implications for the treatment of tumor cells

    Directory of Open Access Journals (Sweden)

    Embi Abraham

    2012-12-01

    Full Text Available Abstract Background In malignant melanoma, it has been published that up to 40% of cancer patients will suffer from brain metastasis. The prognosis for these patients is poor, with a life expectancy of 4 to 6 months. Calcium exchange is involved in numerous cell functions. Recently, three types of cellular calcium sequestration have been reported in the medical literature. The first describes a transgenic mouse model in which an increase of aberrant calcium channels triggers hypertrophy and apoptosis. The second provides a protective mechanism whereby astrocytes in the brain inhibit apoptosis of tumor cells by moving ionic calcium out of the tumor cells thru gap junctions. The third is via calcium chelation, which causes cell apoptosis by converting ionic calcium into a calcium salt. This process has been shown to operate in atrial myocardial cells, thus not allowing the intracellular calcium stores to flow through the myocytes intercalated discs. Ideally chemotherapeutic agents would be those that initiate apoptosis in tumor cells. Presentation of the Hypothesis We hypothesize that the recent reported intracellular calcium sequestration by oxalate chelation, due to its chemical process of converting ionic calcium into a calcium salt, may inhibit the protective effect of astrocytes on brain tumor metastasized melanoma cells by not allowing free calcium to leave the metastatic cells, simultaneously apoptosis of tumor and some healthy adjacent cells could occur. This hypothesis could be extended to include other cancerous tumors such as skin cancers amongst others. Testing the hypothesis Using the experimental model showing the protective mechanism of co-cultured reactive astrocytes and tumor cells treated with oxalates could be used to test this hypothesis in vitro. The calcium specific von Kossa technique could be used to confirm the presence of chelated intracellular calcium architecture of the metastatic cells (which is a sign of apoptosis

  17. 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...

  18. High concentration of calcium ions in Golgi apparatus

    Institute of Scientific and Technical Information of China (English)

    XUESHAOBAI; M.ROBERTNICOUD; 等

    1994-01-01

    The interphase NIH3T3 cells were vitally fluorescentstained with calcium indicator fluo-3 and Glogi probe C6-NBD-ceramide,and then the single cells were examined by laser scanning confocal microscopy(LSCFM) for subcellular distributions of Ca2+ and the location of Golgi apparatus.In these cells,the intracellular Ca2+ were found to be highly concentrated in the Golgi apparatus.The changes of distribution of cytosolic high Ca2+ region and the Golgi apparatus coincided with the cell cycle phase.In calcium free medium,when the plasma membrane of the cells which had been loaded with fluo-3/AM were permeated by digitonin,the fluorescence of the Golgi region decreased far less than that of the cytosol.Our results indicated that the Glogi lumen retained significantly high concentration of free calcium.

  19. Intracellular calcium affects prestin's voltage operating point indirectly via turgor-induced membrane tension

    Science.gov (United States)

    Song, Lei; Santos-Sacchi, Joseph

    2015-12-01

    Recent identification of a calmodulin binding site within prestin's C-terminus indicates that calcium can significantly alter prestin's operating voltage range as gauged by the Boltzmann parameter Vh (Keller et al., J. Neuroscience, 2014). We reasoned that those experiments may have identified the molecular substrate for the protein's tension sensitivity. In an effort to understand how this may happen, we evaluated the effects of turgor pressure on such shifts produced by calcium. We find that the shifts are induced by calcium's ability to reduce turgor pressure during whole cell voltage clamp recording. Clamping turgor pressure to 1kPa, the cell's normal intracellular pressure, completely counters the calcium effect. Furthermore, following unrestrained shifts, collapsing the cells abolishes induced shifts. We conclude that calcium does not work by direct action on prestin's conformational state. The possibility remains that calcium interaction with prestin alters water movements within the cell, possibly via its anion transport function.

  20. Protein-specific localization of a rhodamine-based calcium-sensor in living cells.

    Science.gov (United States)

    Best, Marcel; Porth, Isabel; Hauke, Sebastian; Braun, Felix; Herten, Dirk-Peter; Wombacher, Richard

    2016-06-28

    A small synthetic calcium sensor that can be site-specifically coupled to proteins in living cells by utilizing the bio-orthogonal HaloTag labeling strategy is presented. We synthesized an iodo-derivatized BAPTA chelator with a tetramethyl rhodamine fluorophore that allows further modification by Sonogashira cross-coupling. The presented calcium sensitive dye shows a 200-fold increase in fluorescence upon calcium binding. The derivatization with an aliphatic linker bearing a terminal haloalkane-function by Sonogashira cross-coupling allows the localization of the calcium sensor to Halo fusion proteins which we successfully demonstrate in in vitro and in vivo experiments. The herein reported highly sensitive tetramethyl rhodamine based calcium indicator, which can be selectively localized to proteins, is a powerful tool to determine changes in calcium levels inside living cells with spatiotemporal resolution. PMID:27072883

  1. Extracellular Ca2+ is a danger signal activating the NLRP3 inflammasome through G protein-coupled calcium sensing receptors

    DEFF Research Database (Denmark)

    Rossol, Manuela; Pierer, Matthias; Raulien, Nora; Quandt, Dagmar; Meusch, Undine; Rothe, Kathrin; Schubert, Kristin; Schöneberg, Torsten; Schaefer, Michael; Krügel, Ute; Smajilovic, Sanela; Bräuner-Osborne, Hans; Baerwald, Christoph; Wagner, Ulf

    2012-01-01

    calcium activates the NLRP3 inflammasome via stimulation of G protein-coupled calcium sensing receptors. Activation is mediated by signalling through the calcium-sensing receptor and GPRC6A via the phosphatidyl inositol/Ca(2+) pathway. The resulting increase in the intracellular calcium concentration...... this effect was inhibited in GPRC6A(-/-) mice. Our results demonstrate that G-protein-coupled receptors can activate the inflammasome, and indicate that increased extracellular calcium has a role as a danger signal and amplifier of inflammation....

  2. 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.

  3. Anode properties of alloy Zn 55 Al alloyed by calcium in the medium of NaCl

    International Nuclear Information System (INIS)

    The results of studies of influence of calcium additives on anode properties of zinc-aluminium alloy Zn 55 Al are given. Chemical composition and results of studies of corrosion-electrochemical properties of Zn 55 Al alloy alloyed by calcium are considered.

  4. Structure and properties of gadolinium loaded calcium phosphate glasses

    International Nuclear Information System (INIS)

    The glass samples with composition xGd2O3–(50 − x)CaO–50P2O5 (0 ⩽ x ⩽ 9 mol%) were prepared by the conventional melt quench method. The structure and properties of gadolinium loaded in calcium phosphate glasses were investigated using XRD, SEM, DTA, IR and Raman spectroscopy. The XRD and SEM analysis for the samples show that the majority of samples are amorphous, and crystallization occurs when the content of Gd2O3 containing is up to 6 mol%. Two main crystalline phases, Ca2P2O7 and Gd3(P2O7)3, are embedded in an amorphous matrix. IR and Raman data indicate that glass structure consists of predominantly metaphosphate (Q2) units and the depolymerization of phosphate network with the addition of Gd2O3. Both the chemical durability and the glass transition temperature (Tg) are improved with the increase of Gd2O3, which suggests that the Gd acts a role of strengthening the cross-links between the phosphate chains of the glass

  5. Layered Metal Hydroxides Containing Calcium and Their Structural Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Hyun; Heo, Il; Lee, Sung Han; Oh, Jae Min [College of Science and Technology, Yonsei University, Wonju (Korea, Republic of); Paek, Seung Min [Kyungpook National University, Daegu (Korea, Republic of); Park, Chung Berm; Choi, Ae Jin [National Institute of Horticultural and Herbal Science of R and D Eumseong (Korea, Republic of); Choy, Jin Ho [Ewha Womans University, Seoul (Korea, Republic of)

    2012-06-15

    Layered metal hydroxides (LMHs) containing calcium were synthesized by coprecipitation in solution having two different trivalent metal ions, iron and aluminum. Two mixed metal solutions (Ca{sup 2+}/Al{sup 3+} and Ca{sup 2+}/Fe{sup 3+} = 2/1) were added to sodium hydroxide solution and the final pH was adjusted to {approx}11.5 and {approx}13 for CaAl-and CaFe-LMHs. Powder X-ray diffraction (XRD) for the two LMH samples showed well developed (00l) diffractions indicating 2-dimensional crystal structure of the synthesized LMHs. Rietveld refinement of the X-ray diffraction pattern, the local structure analysis through X-ray absorption spectroscopy, and thermal analysis also confirmed that the synthesized precipitates show typical structure of LMHs. The chemical formulae, Ca{sub 2.04}Al{sub 1}(OH){sub 6}(NO{sub 3}){center_dot}5.25H{sub 2}O and Ca{sub 2.01}Fe{sub 1}(OH){sub 6}(NO{sub 3}){center_dot}4.75H{sub 2}O were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Particle morphology and thermal behavior for the synthesized LMHs were examined by field emission scanning electron microscopy and thermogravimetric differential scanning calorimetry

  6. Solvatochromic Dyes as pH-Independent Indicators for Ionophore Nanosphere-Based Complexometric Titrations.

    Science.gov (United States)

    Zhai, Jingying; Xie, Xiaojiang; Bakker, Eric

    2015-12-15

    For half a century, complexometric titrations of metal ions have been performed with water-soluble chelators and indicators that typically require careful pH control. Very recently, ion-selective nanosphere emulsions were introduced that exhibit ion-exchange properties and are doped with lipophilic ionophores originally developed for chemical ion sensors. They may serve as novel, highly selective and pH independent complexometric reagents. While ion optode emulsions have been demonstrated as useful indicators for such titrations, they exhibit a pH cross-response that unfortunately complicates the identification of the end point. Here, we present pH-independent optode nanospheres as indicators for complexometric titrations, with calcium as an initial example. The nanospheres incorporate an ionic solvatochromic dye (SD), ion exchanger and ionophore. The solvatochromic dye will be only expelled from the core of the nanosphere into the aqueous solution at the end point at which point it results in an optical signal change. The titration curves are demonstrated to be pH-independent and with sharper end points than with previously reported chromoionophore-based optical nanospheres as indicator. The calcium concentration in mineral water was successfully determined using this method. PMID:26595520

  7. Preparation of TiO2 nanotubes/mesoporous calcium silicate composites with controllable drug release.

    Science.gov (United States)

    Xie, Chunling; Li, Ping; Liu, Yan; Luo, Fei; Xiao, Xiufeng

    2016-10-01

    Nanotube structures such as TiO2 nanotube (TNT) arrays produced by self-ordering electrochemical anodization have been extensively explored for drug delivery applications. In this study, we presented a new implantable drug delivery system that combined mesoporous calcium silicate coating with nanotube structures to achieve a controllable drug release of water soluble and antiphlogistic drug loxoprofen sodium. The results showed that the TiO2 nanotubes/mesoporous calcium silicate composites were successfully fabricated by a simple template method and the deposition of mesoporous calcium silicate increased with the soaking time. Moreover, the rate of deposition of biological mesoporous calcium silicate on amorphous TNTs was better than that on anatase TNTs. Further, zinc-incorporated mesoporous calcium silicate coating, produced by adding a certain concentration of zinc nitrate into the soaking system, displayed improved chemical stability. A significant improvement in the drug release characteristics with reduced burst release and sustained release was demonstrated. PMID:27287140

  8. In vitro release modulation from crosslinked pellets for site-specific drug delivery to the gastrointestinal tract. II. Physicochemical characterization of calcium-alginate, calcium-pectinate and calcium-alginate-pectinate pellets.

    Science.gov (United States)

    Pillay, V; Fassihi, R

    1999-05-20

    Pellets of calcium-alginate, calcium-pectinate and calcium-alginate-pectinate were produced via crosslinking in an aqueous medium for site-specific drug delivery in the gastrointestinal tract. A comparative study of their physicochemical characteristics by means of texture analysis, modulated temperature differential scanning calorimetry (MTDSC), scanning electron microscopy and swelling dynamics under different pH conditions was undertaken. It was found that the incorporation of low methoxylated pectin (i.e., degree of methoxylation approximately 35%) together with alginate appears to influence the degree of crosslinking and subsequently the physical, mechanical and resilience behavior. In general, texture analysis of various pellets indicated that both strength and resilience profiles were in the order of calcium-alginate>/=calcium-alginate-pectinate>calcium-pectinate. Calcium-alginate pellets were found to be viscoelastic, while calcium-pectinate was highly brittle. Through the application of MTDSC, depolymerization transitions, reversing and non-reversing heat flow were determined and interpreted for each formulation. Scanning electron microscopy and micro-thermal analysis revealed distinct morphological differences in each case. The influence of and nature of crosslinking, and textural properties of such pellets on drug release rate modulation is discussed. PMID:10332058

  9. "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...

  10. 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...

  11. 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 ...

  12. 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

  13. 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

  14. Mitochondrial response and calcium ion change in apoptotic insect cells induced by SfaMNPV

    Institute of Scientific and Technical Information of China (English)

    XIU Meihong; PENG Jianxin; HONG Huazhu

    2005-01-01

    Mitochondrial responses and changes of calcium ions in apoptotic insect SL-1 cells induced by Syngrapha falcifera multiple nuclear polyhedrosis virus (SfaMNPV) are reported in this paper. By using Rhodamine 123 as a fluorescent labeling probe, flow cytometry analysis and confocal laser scanning microscope observation we observed that the mitochondrial transmembrane potential (△Ψm) began to decrease in SL-1 cells at 4 h post infection and △Ψm reduced continuously with the extension of virus infection. Western blotting indicated that the Bcl-2 level in the mitochondria gradually declined and was down- regulated. Cells undergoing apoptosis were found to have an elevation of cytochrome c in the cytosol and a corresponding decrease in the mitochondria, which indicated that cytochrome c was released from mitochondria into cytosol. These results suggest that mitochondrion-mediated apoptotic signal transduction pathway exists in apoptotic insect cell induced by SfaMNPV. Cytosolic free calcium ([Ca2+]i) concentration rapidly increased after SfaMNPV infection and the elevated calcium was tested to come partly from extracelllular calcium ion influx. Flow cytometry analysis indicated that the apoptosis in SL-1 cells was not influenced by established cytosolic calcium clamped conditions and the EGTA inhibiting calcium influx. Therefore, neither the elevation of cytosolic calcium ion nor extracellular calcium entry was the inducing factor of apoptosis, which hinted that the depletion of ER Ca2+ store contributed to SL-1 cell apoptosis induced by SfaMNPV.

  15. Continental weathering following a Cryogenian glaciation: Evidence from calcium and magnesium isotopes

    Science.gov (United States)

    Kasemann, Simone A.; Pogge von Strandmann, Philip A. E.; Prave, Anthony R.; Fallick, Anthony E.; Elliott, Tim; Hoffmann, Karl-Heinz

    2014-06-01

    A marked ocean acidification event and elevated atmospheric carbon dioxide concentrations following the extreme environmental conditions of the younger Cryogenian glaciation have been inferred from boron isotope measurements. Calcium and magnesium isotope analyses offer additional insights into the processes occurring during this time. Data from Neoproterozoic sections in Namibia indicate that following the end of glaciation the continental weathering flux transitioned from being of mixed carbonate and silicate character to a silicate-dominated one. Combined with the effects of primary dolomite formation in the cap dolostones, this caused the ocean to depart from a state of acidification and return to higher pH after climatic amelioration. Differences in the magnitude of stratigraphic isotopic changes across the continental margin of the southern Congo craton shelf point to local influences modifying and amplifying the global signal, which need to be considered in order to avoid overestimation of the worldwide chemical weathering flux.

  16. Effect of ionizing radiation and calcium on plasma membrane structure

    International Nuclear Information System (INIS)

    Plasma membrane thymocytes were irradiated with doses of 10-104 Gy in the presence of 125 and 1125 μ mol of Ca2+ per 1 mg of membrane proteins. Fluorescence of 1-anilinonaphthalene-8-sulphonate and the degree of puren eximerization were determined. The data obtained indicate that calcium can exert a stabilizing effect on the plasma membrane structure affected by radiation

  17. 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

  18. 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

  19. 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

  20. Intramuscular calcium movements: Experiments from the Soviet Biosatellite Biocosmos

    Science.gov (United States)

    Goblet, C.; Holy, X.; Mounier, Y.

    Experiments have been performed in skeletal muscle fibres from the lateral head of gastrocnemius muscle of female rats. Changes in intramuscular calcium movements due to microgravity conditions have been tested by tension measurements in chemically skinned muscle fibres. Our results show that microgravity induces i) a decrease in maximal muscle strength developped by contractile proteins ii) a decrease of intensity and rate of both Ca release and Ca uptake by the sarcoplasmic reticulum.

  1. Calcium Oxalate Crystals in Eucalypt Ectomycorrhizae: Morphochemical Characterization

    OpenAIRE

    Pylro, Victor Satler; de Freitas, André Luiz Moreira; Otoni, Wagner Campos; da Silva, Ivo Ribeiro; Borges, Arnaldo Chaer; Costa, Maurício Dutra

    2013-01-01

    Ectomycorrhizal fungi are ubiquitous in forest ecosystems, benefitting plants principally by increasing the uptake of water and nutrients such as calcium from the soil. Previous work has demonstrated accumulation of crystallites in eucalypt ectomycorrhizas, but detailed morphological and chemical characterization of these crystals has not been performed. In this work, cross sections of acetic acid-treated and cleared ectomycorrhizal fragments were visualized by polarized light microscopy to e...

  2. 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...

  3. 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.

  4. Influence of calcium on ceramide-1-phosphate monolayers.

    Science.gov (United States)

    Oliveira, Joana S L; Brezesinski, Gerald; Hill, Alexandra; Gericke, Arne

    2016-01-01

    Ceramide-1-phosphate (C1P) plays an important role in several biological processes, being identified as a key regulator of many protein functions. For instance, it acts as a mediator of inflammatory responses. The mediation of the inflammation process happens due to the interaction of C1P with the C2 domain of cPLA2α, an effector protein that needs the presence of submicromolar concentrations of calcium ions. The aim of this study was to determine the phase behaviour and structural properties of C1P in the presence and absence of millimolar quantities of calcium in a well-defined pH environment. For that purpose, we used monomolecular films of C1P at the soft air/liquid interface with calcium ions in the subphase. The pH was varied to change the protonation degree of the C1P head group. We used surface pressure versus molecular area isotherms coupled with other monolayer techniques as Brewster angle microscopy (BAM), infrared reflection-absorption spectroscopy (IRRAS) and grazing incidence X-ray diffraction (GIXD). The isotherms indicate that C1P monolayers are in a condensed state in the presence of calcium ions, regardless of the pH. At higher pH without calcium ions, the monolayer is in a liquid-expanded state due to repulsion between the negatively charged phosphate groups of the C1P molecules. When divalent calcium ions are added, they are able to bridge the highly charged phosphate groups, enhancing the regular arrangement of the head groups. Similar solidification of the monolayer structure can be seen in the presence of a 150 times larger concentration of monovalent sodium ions. Therefore, calcium ions have clearly a strong affinity for the phosphomonoester of C1P. PMID:26977381

  5. Mathematical model for calcium-assisted epidermal homeostasis.

    Science.gov (United States)

    Kobayashi, Yasuaki; Sawabu, Yusuke; Kitahata, Hiroyuki; Denda, Mitsuhiro; Nagayama, Masaharu

    2016-05-21

    Using a mathematical model of the epidermis, we propose a mechanism of epidermal homeostasis mediated by calcium dynamics. We show that calcium dynamics beneath the stratum corneum can reduce spatio-temporal fluctuations of the layered structure of the epidermis. We also demonstrate that our model can reproduce experimental results that the recovery from a barrier disruption is faster when the disrupted site is exposed to air. In particular, simulation results indicate that the recovery speed depends on the size of barrier disruption. PMID:26953648

  6. Productivity and nutritive value of bluestem grass fertilized with calcium and magnesium silicate

    OpenAIRE

    Cinthya Souza Santana; Laura Souza Santos; Greiciele de Morais; Luiz Arnaldo Fernandes; Luciana Castro Geraseev

    2016-01-01

    This study evaluated the effect of application of calcium and magnesium silicate on the productivity, chemical composition and in situ ruminal degradation of bluestem grass (Andropogon gayanus Kunth, cv. Baeti; Embrapa 23) during the rainy and dry seasons. The design consisted of completely randomized blocks in a 6x2 factorial scheme (six silicate doses and two cutting seasons), arranged in plots subdivided over time. The plots were the calcium and magnesium silicate doses (0, 200, 400, 600, ...

  7. The effect of dietary calcium and phosphorus supplementation in zeolite a treated dry cows on periparturient calcium and phosphorus homeostasis

    DEFF Research Database (Denmark)

    Thilsing, Trine; Larsen, T; Jørgensen, R J;

    2007-01-01

    Previous studies have proved the possibility of preventing parturient hypocalcaemia by zeolite A supplementation during the dry period, and a recent in vitro study has indicated a marked calcium (Ca) as well as phosphorus (P) binding effect of zeolite A in rumen fluid solutions. Because of the co...

  8. 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

  9. 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

  10. Formulation Optimization of Rosuvastatin Calcium-Loaded Solid Lipid Nanoparticles by 32 Full-Factorial Design

    Directory of Open Access Journals (Sweden)

    Kruti A. Dhoranwala

    2015-12-01

    Full Text Available The present investigation was aimed at developing Rosuvastatin Calcium loaded solid lipid nanoparticles (SLNs. The SLNs were prepared using high pressure homogenization technique. Glyceryl monostearate (GMS and Poloxamer 188 were employed as lipid carrier and surfactant respectively. A two factor, three level (32 full factorial design was applied to study the effect of independent variables i.e. amount of GMS (X1 and amount of Poloxamer 188 (X2 on dependent variables i.e. Particle size (Y1 and % entrapment efficiency (Y2. Particles size, % entrapment efficiency (%EE, zeta potential, drug content, in vitro drug release and particles morphology were evaluated for SLNs. Contour plots and response surface plots showed visual representation of relationship between the experimental responses (dependent variables and the set of input (independent variables. The adequacy of the regression model was verified by a check point analysis. The optimized batch (B10 contained 2.2 gm of GMS and 1% of Poloxamer 188. Batch B 10 exhibited mean particle size of 529.6 nm ± 6.36 nm; polydispersity index (PDI of 0.306 ± 0.042; zeta potential of -31.88 mV ± (-2.50 mV and %EE of 48.90% ± 1.72%. The drug release experiments exhibited an initial rapid release followed by sustained release extended upto 36 h. Differential scanning calorimetry (DSC studies showed that there was no chemical interaction between drug (Rosuvastatin Calcium and lipid (GMS whereas scanning electron microscopy (SEM studies indicated that Rosuvastatin Calcium loaded SLNs are spherical, discrete and homogenous. Accelerated stability studies showed that there was no significant change occurring in the responses after storage for a total period of 3 months.

  11. Sound construction of risk indicators

    DEFF Research Database (Denmark)

    Sørensen, Peter Borgen; Kjær, Christian; Thomsen, Marianne

      In spite of the great effort in the area of environmental risk assessment of chemicals, a critical amount of uncertainty is still a reality due to high complexity of the governing risk problem. Unexpected adverse effects may thus take place event though the risk assessment predicts no-risk. Some...... chemicals are even lacking risk assessment due to a priori judgment based on risk screening methods that bypass further risk assessment activity. It is thus advisable to set up a safety net under the risk assessment of chemicals and this poster suggests a supporting paradigm using risk indicators....... The purpose is to develop a novel approach for risk indicators that can support risk minimization. Risk indicators can identify risk reduction and thus yield a time trend analysis of the progress in risk level. Another option is to evaluate the current condition in relation to a reference condition defined...

  12. Effects of extremely low frequency electromagnetic fields on intracellular calcium transients in cardiomyocytes.

    Science.gov (United States)

    Wei, Jinhong; Sun, Junqing; Xu, Hao; Shi, Liang; Sun, Lijun; Zhang, Jianbao

    2015-03-01

    Calcium transients play an essential role in cardiomyocytes and electromagnetic fields (EMF) and affect intracellular calcium levels in many types of cells. Effects of EMF on intracellular calcium transients in cardiomyocytes are not well studied. The aim of this study was to assess whether extremely low frequency electromagnetic fields (ELF-EMF) could affect intracellular calcium transients in cardiomyocytes. Cardiomyocytes isolated from neonatal Sprague-Dawley rats were exposed to rectangular-wave pulsed ELF-EMF at four different frequencies (15 Hz, 50 Hz, 75 Hz and 100 Hz) and at a flux density of 2 mT. Intracellular calcium concentration ([Ca(2+)]i) was measured using Fura-2/AM and spectrofluorometry. Perfusion of cardiomyocytes with a high concentration of caffeine (10 mM) was carried out to verify the function of the cardiac Na(+)/Ca(2+) exchanger (NCX) and the activity of sarco(endo)-plasmic reticulum Ca(2+)-ATPase (SERCA2a). The results showed that ELF-EMF enhanced the activities of NCX and SERCA2a, increased [Ca(2+)]i baseline level and frequency of calcium transients in cardiomyocytes and decreased the amplitude of calcium transients and calcium level in sarcoplasmic reticulum. These results indicated that ELF-EMF can regulate calcium-associated activities in cardiomyocytes. PMID:24499289

  13. Noscapine protects OLN-93 oligodendrocytes from ischemia-reperfusion damage: Calcium and nitric oxide involvement.

    Science.gov (United States)

    Nadjafi, S; Ebrahimi, S-A; Rahbar-Roshandel, N

    2015-12-01

    This study was carried out to evaluate the effects of noscapine, a benzylisoquinoline alkaloid from opium poppy, on oligodendrocyte during ischemia/reperfusion-induced excitotoxic injury. Changes in intracellular calcium levels due to chemical ischemia and nitric oxide (NO) production during ischemia/reperfusion were evaluated as the hallmarks of ischemia-derived excitotoxic event. OLN-93 cell line (a permanent immature rat oligodendrocyte) was used as a model of oligodendrocyte. 30- or 60-minute-oxygen-glucose deprivation/24 hours reperfusion were used to induce excitotoxicity. MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) assay was used to evaluate cell viability. Ratiometric fluorescence microscopy using Ca(2+)-sensitive indicator Fura-2/AM was utilized to assess intracellular calcium levels. NO production was evaluated by Griess method. Noscapine (4 μM) significantly attenuated intracellular Ca(2+) elevation (P < 0.001). Also, noscapine significantly decreased NO production during a 30-minute oxygen-glucose deprivation/reperfusion (P < 0.01). The inhibitory effect of noscapine (4 μM) on intracellular Ca(2+) was greater than ionotropic glutamate receptors antagonists. Noscapine is protective against ischemia/reperfusion-induced excitotoxic injury in OLN-93 oligodendrocyte. This protective effect seems to be related to attenuation of intracellular Ca(2+) overload and NO production. PMID:26690027

  14. The Role of Calcium Scoring in Coronary CTA

    Directory of Open Access Journals (Sweden)

    N Shirvandehi

    2009-01-01

    Full Text Available "nCoronary artery disease is the single largest cause of mortality, and is implicated in one of every five deaths. Conventional risk factors fail to identify one third of deaths caused by CAD. The currently available screening tools for coronary artery disease include Framingham risk assessment, clinical examination, and stress testing. "nIt is of interest that most coronary events occur in the territory of coronary arteries that do not demonstrate prior high grade stenosis. "nComplications of atherosclerotic plaque such as rupture or erosion with subsequent thrombus formation are important events leading to acute coronary syndrome. "nMany different factors including plaque composition, hemodynamic, endothelial function, and blood thrombogenicity may influence which plaques lead to hemodynamically significant events. "nNonetheless, there is a strong relation between the extent of coronary plaque burden and the risk of coronary event. "nSince atherosclerosis is the only disease process associated with calcification of coronary arteries, the degree of coronary calcification as demonstrated by CT is predictive of the overall burden of atherosclerotic plaque. "nThe role of coronary calcium scoring in assessing the risk for future coronary events has been a subject of considerable controversy. It is most important to understand that an elevated burden of coronary calcium may not indicate the presence of significant coronary stenosis, but is associated with a higher risk of a coronary event. "nCalcium scoring is based on the identification of high density material within the coronary circulation on a noncontrast CTscan. Both the EBCT and MDCT have been used for the evaluation of coronary calcium. "nThe current literature suggests that MDCT is comparable to EBCT for coronary calcium screening. "nCalcium scoring is a simple test that should take no more than 5 minutes. A prospective ECG gated scan with 3 mm slice thickness is obtained from the level of

  15. Topological Indices Study of Molecular Structure in Anticancer Drugs

    OpenAIRE

    Wei Gao; Weifan Wang; Mohammad Reza Farahani

    2016-01-01

    Numerous studies indicate that there is strong inherent relationship between the chemical characteristics of chemical compounds and drugs (e.g., boiling point and melting point) and their molecular structures. Topological indices defined on these chemical molecular structures can help researchers better understand the physical features, chemical reactivity, and biological activity. Thus, the study of the topological indices on chemical structure of chemical materials and drugs can make up for...

  16. 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.)

  17. Casein Phosphopeptide-Amorphous Calcium Phosphate Nanocomplexes: A Structural Model.

    Science.gov (United States)

    Cross, Keith J; Huq, N Laila; Reynolds, Eric C

    2016-08-01

    Tryptic digestion of the calcium-sensitive caseins yields casein phosphopeptides (CPP) that contain clusters of phosphorylated seryl residues. The CPP stabilize calcium and phosphate ions through the formation of complexes. The calcium phosphate in these complexes is biologically available for intestinal absorption and remineralization of subsurface lesions in tooth enamel. We have studied the structure of the complexes formed by the CPP with calcium phosphate using a variety of nuclear magnetic resonance (NMR) techniques. Translational diffusion measurements indicated that the β-CN(1-25)-ACP nanocomplex has a hydrodynamic radius of 1.526 ± 0.044 nm at pH 6.0, which increases to 1.923 ± 0.082 nm at pH 9.0. (1)H NMR spectra were well resolved, and (3)JH(N)-H(α) measurements ranged from a low of 5.5 Hz to a high of 8.1 Hz. Total correlation spectroscopy and nuclear Overhauser effect spectroscopy spectra were acquired and sequentially assigned. Experiments described in this paper have allowed the development of a structural model of the β-CN(1-25)-amorphous calcium phosphate nanocomplex. PMID:27434168

  18. The mechanical environment modulates intracellular calcium oscillation activities of myofibroblasts.

    Directory of Open Access Journals (Sweden)

    Charles Godbout

    Full Text Available Myofibroblast contraction is fundamental in the excessive tissue remodeling that is characteristic of fibrotic tissue contractures. Tissue remodeling during development of fibrosis leads to gradually increasing stiffness of the extracellular matrix. We propose that this increased stiffness positively feeds back on the contractile activities of myofibroblasts. We have previously shown that cycles of contraction directly correlate with periodic intracellular calcium oscillations in cultured myofibroblasts. We analyze cytosolic calcium dynamics using fluorescent calcium indicators to evaluate the possible impact of mechanical stress on myofibroblast contractile activity. To modulate extracellular mechanics, we seeded primary rat subcutaneous myofibroblasts on silicone substrates and into collagen gels of different elastic modulus. We modulated cell stress by cell growth on differently adhesive culture substrates, by restricting cell spreading area on micro-printed adhesive islands, and depolymerizing actin with Cytochalasin D. In general, calcium oscillation frequencies in myofibroblasts increased with increasing mechanical challenge. These results provide new insight on how changing mechanical conditions for myofibroblasts are encoded in calcium oscillations and possibly explain how reparative cells adapt their contractile behavior to the stresses occurring in normal and pathological tissue repair.

  19. 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

  20. In vitro osteoblast-like and endothelial cells' response to calcium silicate/calcium phosphate cement

    International Nuclear Information System (INIS)

    This study aims to investigate the interaction between calcium silicate/calcium phosphate cement (CS/CPC) and osteogenesis, in particular the in vitro osteoblast-like and endothelial cells' response to CS/CPC. The effect of CS/CPC on cell attachment, proliferation and differentiation of murine osteoblast-like cell MC3T3-E1, as well as the influence on the cell attachment and proliferation of human umbilical vein endothelial cell (HUVEC), was studied in detail. Our results indicated that CS/CPC exhibited excellent biocompatibility to the osteoblast-like cells. Moreover, the morphology and cytoskeleton organization of MC3T3-E1 cultured on the CS/CPC disks suggested that CS/CPC induced better cell adhesion and cell spreading. Simultaneously, cell proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 were significantly improved after 3 and 7 days of culture on CS/CPC disks in comparison with CPC disks. Additionally, on CS/CPC disks, HUVEC attached well on day 1 and cell proliferation was also greatly enhanced by day 7. Collectively, these results suggest that the introduction of calcium silicate may improve the cell response involved in the osteogenesis and thus may be beneficial to further modify CPC as a better bone repairing material.