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Sample records for calcium 40 beams

  1. Ion beam deposition of calcium hydroxyapatite

    International Nuclear Information System (INIS)

    Calcium hydroxyapatite has been sputtered on glass and Ti-6Al-4V substrates using a 1.5 kV argon ion beam. The films have been examined by X- ray diffraction analysis, energy dispersive spectroscopy, scanning electron microscopy, and adhesion testing. Results of this experimentation are presented

  2. 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...

  3. Microanalyses of the hydroxyl—poly—calcium sodium phosphate coatings produced by ion beam assisted deposition

    Institute of Scientific and Technical Information of China (English)

    LIUZhong-Yang; WANGChang-Xing; 等

    2002-01-01

    Thin calcium phosphate catings on titanium alloy substrates were prepared by Ar+ ion beam assisted deposition(IBAD) from hydroxyl-poly-calcium sodium phosphate(HPPA) target.The coatings were analyzed by XRD,FTIR,XPS,These analyses revealed that the as-deposited films were amorphous or no apparent crystallinity.No distinct absorption band of the hydroxyl group was observed in FTIR spectra of the coatings but new absorption bands were presented for CO3-2,The calcium to phosphorous ratio of these catings in different IBAD conditions varied from 0.46 to 3.36.

  4. The effect of E-beam irradiation on the sterilization for calcium lactate

    International Nuclear Information System (INIS)

    The sterilization of calcium lactate as food additive was performed by electron beam. The quality, numbers of colony, gather mold and yeasts were determined before and after irradiation. It was found that the mortality of microbes significantly decreased with the increment of absorbed doses and the D10 value of colony number was determined to be 4.38 kGy. And the quality of calcium lactate satisfied the food standard though its mass fraction decreased a little after irradiation with electron beam of 10 kGy. (authors)

  5. 40 CFR 424.40 - Applicability; description of the covered calcium carbide furnaces with wet air pollution control...

    Science.gov (United States)

    2010-07-01

    ... covered calcium carbide furnaces with wet air pollution control devices subcategory. 424.40 Section 424.40... FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Covered Calcium Carbide Furnaces With Wet Air Pollution... with wet air pollution control devices subcategory. The provisions of this subpart are applicable...

  6. 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...

  7. Detection of coronary calcium with electron beam tomography in coronary artery disease

    International Nuclear Information System (INIS)

    Purpose: Coronary calcium is a powerful indicator of arteriosclerosis and can be detected very precisely with electron beam tomography. The method can be applied in patients with known coronary artery disease or in asymptomatic patients at risk of arteriosclerotic disease. Results: At the University of Munich we performed an EBT scan of the heart in 1100 patients within the last year. In 567 patients coronary angiography was performed also (±3 days). Confirming previous reports in the literature, we found a correlation of the calcium score with the age and gender of the patients. Severe coronary artery disease (stenoses ≥ 75%) was associated with significantly more calcium than less severe CAD. The calcium score did not discriminate between one-, two- and three-vessel disease. The site of calcification does not correlate with the localization of stenoses. Thirty-three percent of the patients with significant coronary artery disease showed a normal age-adjusted calcium score; a total of 8.1% of patients with severe stenoses did not reveal any coronary calcification (score =0). With asymptomatic patients there are only a few studies available. Soft plaques cannot be detected with EBT, but in most patients soft plaques occur together with hard plaques. Our results show that spiral CT of the newest generation may also be used for calcium screening. There was an excellent correlation of the calcium scores of EBT and spiral CT at all levels of calcification. Discussion: Coronary calcium is a sensitive marker of coronary artery disease. In the clinical setting EBT is indicated in patients with known coronary artery disease (to evaluate prognosis), in patients who are unable to perform a stress test, and in patients with atypical chest pain. However, lack of calcification may be associated with severe stenoses in a minority of patients. The clinical value in asymptomatic patients needs to be defined: Randomized studies are necessary. We see a possible indication in

  8. Fabrication and characterization of graded calcium phosphate coatings produced by ion beam sputtering/mixing deposition

    International Nuclear Information System (INIS)

    Ion beam sputtering/mixing deposition was used to produce thin calcium phosphate coatings on titanium substrate from the hydroxyapatite target. It was found that as-deposited coatings were amorphous. No distinct absorption band of the hydroxyl group was observed in FTIR spectra of the coatings but new absorption bands were present for CO32-, which was brought about during the deposition process. Scanning electron microscopy revealed that the deposited coatings had a uniform and dense structure. The calcium to phosphorous ratio of these coatings varied between 2.0 and 8.0. Analyses of XPS data revealed that the coating could be divided into four distinctive zones, and a graded structure was achieved in the as-received coating. Scratch tests showed that the coatings adhered well to the substrate

  9. Lenticular energy metabolism during exogenous calcium deprivation and during recovery: effects of dextran-40.

    Science.gov (United States)

    Glonek, T; Kopp, S J; Greiner, J V; Sanders, D R

    1985-02-01

    Phosphatic metabolites of the intact rabbit lens were quantitated as a function of time by phosphorus-31 nuclear magnetic resonance (P-31 NMR) spectroscopy during in vitro incubations at 37 degrees C in calcium-sufficient and calcium-deficient modified Earle's buffer with and without the osmotic agent, Dextran-40. Intralenticular pH was determined from the resonance shift position of inorganic orthophosphate (Pi). Incubation of lenses in calcium-deficient buffer resulted in a pronounced, time-dependent decrease in lenticular adenosine triphosphate (ATP) levels. The half-life of ATP within the lens was 11 hr under these experimental conditions. A concomitant, essentially stoichiometric increase in adenosine diphosphate and Pi levels was observed also. The other phosphatic metabolites were unaffected by exogenous calcium deprivation except for adenosine and inosine monophosphate which accumulated with time. Dextran-40 (6%), which has been shown to prevent lens swelling under these same experimental conditions, did not influence the metabolic responses of the lens to external calcium deprivation and did not facilitate subsequent restoration of lens phosphatic metabolites following restoration of a physiologic calcium concentration to the supporting medium. The Dextran-40 did, however, promote the retention of intralenticular pH environment during the experimental period. These findings suggest that the previously reported Dextran-40-dependent recovery of intralenticular sodium and potassium concentrations to control levels following 10 hr of incubation in calcium-deficient media cannot be attributed to a direct energy-sparing action of Dextran-40 on lenticular energy metabolism. Instead, the mechanistic basis for the action of Dextran-40 would appear to be related to its colloid osmotic properties and its ability to prevent lenticular swelling, which otherwise occurs in the absence of Dextran under these experimental conditions. PMID:2579839

  10. Correlation between obstructive coronary artery disease and electron beam tomography coronary artery calcium scan

    International Nuclear Information System (INIS)

    To determine the correlation between obstructive coronary artery disease and electron beam tomography coronary artery calcium(EBT CAC) scan and to measure the difference in calcium score according to symptoms. Materials and Methods : Fifty-six patients underwent EBT CAC scanning and either coronary angiography or stress thallium 201 scanning or the treadmill test. When the results were positive, coronary artery obstructive disease(CAOD) was assumed to be present. The patients were divided into three groups : symptomatic CAOD,asymptomatic CAOD, and asymptomatic non- CAOD; those with a previous history of myocardial ischemia or who showed positive results in any of the three tests relating to typical symptoms of angina were assigned to the symptomatic group. Results : The number of cases assigned to group to group 1,2 and 3 was 19, 16 and 21, respectively; total CAC scores were 571 ± 751, 600 ± 726 293± 401, respectively. The difference in CAC score between asymptomatic CAOD and asymptomatic non- CAOD was not statistically significant(p=0.079) but in asymptomatic CAOD, the score tended to be higher. The CAC score was not different between symptomatic and asymptomatic CAOD(p>0.1). When the CAC threshold was 1, sensitivity was 89% and specificity was 14%;when the threshold was 200, sensitivity was 60% and specificity was 67%. Conclusion : When the EBT CAC score is high, further evaluation provides early evidence of coronary artery obstructive disease

  11. Nanocrystalline biphasic resorbable calcium phosphate (HAp/β-TCP) thin film prepared by electron beam evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Elayaraja, K.; Chandra, V. Sarath; Joshy, M.I. Ahymah; Suganthi, R.V. [Crystal Growth Centre, Anna University, Chennai 600025, Tamil Nadu (India); Asokan, K. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kalkura, S. Narayana, E-mail: kalkura@yahoo.com [Crystal Growth Centre, Anna University, Chennai 600025, Tamil Nadu (India)

    2013-06-01

    Biphasic calcium phosphate (BCP) thin film having resorbable β-tricalcium phosphate (β-TCP) and non-resorbable hydroxyapatite (HAp) phases having enhanced bioactivity was synthesized by electron beam evaporation technique. Nanosized BCP was deposited as a layer (500 nm) on (0 0 1) silicon substrate by electron beam evaporation and crystalline phase of samples were found to improve on annealing at 700 °C. Uniform deposition of calcium phosphate on silicon substrate was verified from elemental mapping using scanning electron microscope (SEM-EDX). Annealing of the samples led to a decrease in surface roughness, hydrophobicity and dissolution of the coating layer. Amoxicillin loaded thin films exhibited significant bacterial resistance. In addition, BCP thin films did not exhibit any cytotoxicity. Antibiotics incorporated BCP coated implants might prevent the post-surgical infections and could promote bone-bonding of orthopedic devices.

  12. Nanocrystalline biphasic resorbable calcium phosphate (HAp/β-TCP) thin film prepared by electron beam evaporation technique

    International Nuclear Information System (INIS)

    Biphasic calcium phosphate (BCP) thin film having resorbable β-tricalcium phosphate (β-TCP) and non-resorbable hydroxyapatite (HAp) phases having enhanced bioactivity was synthesized by electron beam evaporation technique. Nanosized BCP was deposited as a layer (500 nm) on (0 0 1) silicon substrate by electron beam evaporation and crystalline phase of samples were found to improve on annealing at 700 °C. Uniform deposition of calcium phosphate on silicon substrate was verified from elemental mapping using scanning electron microscope (SEM-EDX). Annealing of the samples led to a decrease in surface roughness, hydrophobicity and dissolution of the coating layer. Amoxicillin loaded thin films exhibited significant bacterial resistance. In addition, BCP thin films did not exhibit any cytotoxicity. Antibiotics incorporated BCP coated implants might prevent the post-surgical infections and could promote bone-bonding of orthopedic devices.

  13. Segregation and evaporation behaviors of aluminum and calcium in silicon during solidification process induced by electron beam

    International Nuclear Information System (INIS)

    An experimental investigation into the removal of aluminum (Al) and calcium (Ca) from molten silicon by using electron beam melting was carried out. Based on the distributions of Al and Ca along the growth direction of the ingot under different solidification conditions, the influence of segregation and evaporation behaviors on the removal of such impurities with both high saturated vapor pressure and low segregation coefficients was investigated. The results showed that the distributions of impurities depend upon the interaction between segregation and evaporation, so that the removal efficiency can be further improved by adjusting the melting parameters. Compared with the traditional electron beam melting process, the energy consumption decreases by 20% during the whole melting and solidification process. It is considered to be a more effective way for the purification of silicon and the reduction of energy consumption by electron beam melting. (paper)

  14. RESIDUAL GAS IONIZATION BEAM PROFILE MONITOR ON 40MeV H— BEAM TRANSPORT LINE

    Institute of Scientific and Technical Information of China (English)

    徐伟鹏; E.Takasaki

    1995-01-01

    The monitor is composed of a pair of electrodes,a single stage of microchannel plate,a phosphor screen,a CCD camera and a PC computer,To obtain a good uniform collecting field,forming electrodes system is used instead of that with a resistive divider,The readout system is performed by the phosphor screen and the CCD camera because the spatial resolution is not limited by the mechanical structure like the anode strip type and such video display system is very useful for beam studies and operation of the 40MeV linac,Besides,the design and test results are described in detail.

  15. High-power continuous-wave tunable 544- and 272-nm beams based on a diode-oscillator fiber-amplifier for calcium spectroscopy

    Science.gov (United States)

    Ko, Kwang-Hoon; Kim, Yonghee; Park, Hyunmin; Cha, Yong-Ho; Kim, Taek-Soo; Lee, Lim; Lim, Gwon; Han, Jaemin; Ko, Kwang-Hee; Jeong, Do-Young

    2015-08-01

    Continuous-wave single-frequency tunable 544- and 272-nm beams have been demonstrated by the second- and fourth-harmonic conversions of a 1088-nm fundamental beam from a diode-oscillator fiber-amplifier. The single-pass second-harmonic generation with a MgO-doped periodically poled stoichiometric LiTaO3 crystal and the external-cavity frequency-doubling technique with a bulk BBO crystal were employed to achieve an approximately 6-W 544-nm beam and a 1.5-W 272-nm beam, respectively. We characterized the second- and fourth-harmonic generations and discussed their applications to calcium spectroscopy.

  16. Nanoclusters of CaSe in calcium-doped Bi2Se3 grown by molecular-beam epitaxy

    Science.gov (United States)

    Shang, Panju; Guo, Xin; Zhao, Bao; Dai, Xianqi; Bin, Li; Jia, Jinfeng; Li, Quan; Xie, Maohai

    2016-02-01

    In calcium (Ca) doped Bi2Se3 films grown by molecular beam epitaxy, nanoclusters of CaSe are revealed by high-angle annular dark field imaging and energy dispersive x-ray spectroscopy analysis using a scanning transmission electron microscope. As the interface between the ordinary insulator CaSe and topological insulator, Bi2Se3, can host topological nontrivial interface state, this represents an interesting material system for further studies. We show by first principles total energy calculations that aggregation of Ca atoms in Bi2Se3 is driven by energy minimization and a preferential intercalation of Ca in the van der Waals gap between quintuple layers of Bi2Se3 induces reordering of atomic stacking and causes an increasing amount of stacking faults in film. The above findings also provide an explanation of less-than-expected electrical carrier (hole) concentrations in Ca-doped samples.

  17. 40 CFR 415.300 - Applicability; description of the calcium carbonate production subcategory.

    Science.gov (United States)

    2010-07-01

    ... calcium carbonate production subcategory. 415.300 Section 415.300 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbonate Production Subcategory § 415.300 Applicability; description of the calcium carbonate production subcategory. The provisions of this subpart are applicable to...

  18. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Science.gov (United States)

    2010-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to...

  19. Improved laser damage threshold performance of calcium fluoride optical surfaces via Accelerated Neutral Atom Beam (ANAB) processing

    Science.gov (United States)

    Kirkpatrick, S.; Walsh, M.; Svrluga, R.; Thomas, M.

    2015-11-01

    Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface

  20. 40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No....

  1. Primary attenuation coefficient of a p(66)/Be(40) neutron therapy beam

    International Nuclear Information System (INIS)

    The concept of primary and scattered dose components of a radiotherapy beam is commonly used in radiotherapy planning. Four different methods which have been used for photon beams, were applied to determine the primary dose linear attenuation coefficient in water in a p(66)/Be(40) neutron beam. They were: the extrapolation of measured tissue-maximum ratios to zero field size; linear attenuation measurements; dose measurements in phantom with and without a central axis attenuator; and fitting a central axis kerma model, based on convolution techniques, to measured percentage depth dose data. 15 refs., 3 figs., 1 tab

  2. The TFTR 40 MW neutral beam injection system and DT operations

    International Nuclear Information System (INIS)

    Since December 1993, TFTR has performed DT experiments using tritium fuel provided mainly by neutral beam injection. Significant alpha particle populations and reactor-like conditions have been achieved at the plasma core, and fusion output power has risen to a record 10.7 MW using a record 40 MW NB heating. Tritium neutral beams have injected into over 480 DT plasmas and greater than 500 kCi have been processed through the neutral beam gas, cryo, and vacuum systems. Beam tritium injections, as well as tritium feedstock delivery and disposal, have now become part of routine operations. Shot reliability with tritium is about 90% and is comparable to deuterium shot reliability. This paper describes the neutral beam DT experience including the preparations, modifications, and operating techniques that led to this high level of success, as well as the critical differences in beam operations encountered during DT operations. Also, the neutral beam maintenance and repair history during DT operations, the corrective actions taken, and procedures developed for handling tritium contaminated components are discussed in the context of supporting a continuous DT program

  3. Response of silicon multistrip detectors and a cesium iodide scintillator to a calcium ion beam of 0.5 GeV/u

    International Nuclear Information System (INIS)

    We have constructed and operated charge preamplifiers for silicon strip detectors with a dynamic range extending from fractions of minimum ionising particle (MIP) up to 16 124 MIPs. These silicon detectors combined with time-of-flight counters and cesium iodide scintillator form a segment of the VENUS detector that has been exposed to a calcium beam of 0.5 GeV/u at the GSI accelerator. The aim of the instrument is the identification of all nuclides of the periodic table of the elements. Measurements of electronic noise, cross-talk among channels and energy deposit resolutions in various experimental conditions for silicon detectors are given. The measured light output of the CsI(Tl) crystal induced by calcium is compared with that extrapolated from lower-energy data of various nuclide species determined in other experiments. The charge resolution for calcium ions, determined by the dE/dx detectors and TOF counters of time resolution of 55±7 ps, amounts to 0.42 charge units (rms). Improvements in ion discrimination with respect to the present detector configuration are considered. (orig.)

  4. Response of silicon multistrip detectors and a cesium iodide scintillator to a calcium ion beam of 0.5 GeV/u

    Energy Technology Data Exchange (ETDEWEB)

    Codino, A.; Miozza, M.; Brunetti, M.T.; Checcucci, B.; Federico, C.; Grimani, C.; Lanfranchi, M.; Macchiaiolo, T.; Menichelli, M.; Maffei, P.; Vocca, H. [Istituto Nazionale di Fisica Nucleare, Perugia (Italy); Plouin, F. [Laboratoire National de Saturne, 91191 Gif-sur-Yvette Cedex (France)

    1997-10-21

    We have constructed and operated charge preamplifiers for silicon strip detectors with a dynamic range extending from fractions of minimum ionising particle (MIP) up to 16 124 MIPs. These silicon detectors combined with time-of-flight counters and cesium iodide scintillator form a segment of the VENUS detector that has been exposed to a calcium beam of 0.5 GeV/u at the GSI accelerator. The aim of the instrument is the identification of all nuclides of the periodic table of the elements. Measurements of electronic noise, cross-talk among channels and energy deposit resolutions in various experimental conditions for silicon detectors are given. The measured light output of the CsI(Tl) crystal induced by calcium is compared with that extrapolated from lower-energy data of various nuclide species determined in other experiments. The charge resolution for calcium ions, determined by the dE/dx detectors and TOF counters of time resolution of 55{+-}7 ps, amounts to 0.42 charge units (rms). Improvements in ion discrimination with respect to the present detector configuration are considered. (orig.). 12 refs.

  5. Characterization of 1 MW, 40 keV, 1 s neutral beam for plasma heating

    International Nuclear Information System (INIS)

    Neutral beam with geometrical focusing for plasma heating in moderate-size plasma devices has been developed in Budker Institute of Nuclear Physics, Novosibirsk. When operated with hydrogen, the neutral beam power is 1 MW, pulse duration is 1 s, beam energy is 40 keV, and angular divergence is 1.2 deg. Initial ion beam is extracted and accelerated by triode multiapertures ion-optical system. To produce 1 MW neutral beam, about 40 A proton current is extracted with nominal current density of 320 mA/cm2. Ion-optical system has 200 mm diameter grids with 44% transparency. The grids have inertia cooling and heat is removed between the pulses by water flowing in channels placed on periphery of the grids. A plasma emitter for ion extraction is produced by rf-plasma box. Ion species mix of rf plasma source amounts to 70%, 20%, and 10% of H+, H2+, and H3+ ions, respectively, by current. Heavy impurities contribute less than 0.3%.

  6. Ground-water activation from the upcoming operation of MI40 beam absorber

    International Nuclear Information System (INIS)

    During the course of normal operation, a particle accelerator can produce radionuclides in the adjacent soil and in the beam line elements through the interactions of accelerated particles and/or secondary particles produced in the beam absorbers, targets, and sometimes elsewhere through routine beam losses. The production and concentration of these radionuclides depends on the beam parameters such as energy, intensity, particle type, and target configuration. The radionuclides produced in the soil can potentially migrate to the ground water. Soil activation and migration to the ground water depends on the details of the local hydrogeology. Generally, very few places such as the beam stops, target stations, injection and extraction sectors can have high enough radiation fields to produce radionuclides in the soil outside the enclosures. During the design, construction, or an upgrade in the intensity of existing beams, measures are taken to minimize the production of activated soil. The only leachable radionuclides known to be produced in the Fermilab soil are 3H, 7Be , 22Na, 45Ca and 54Mn and it has been determined that only 3H, and 22Na, because of their longer half lives and greater leachabilities, may significantly impact ground water resources.In the past, Fermilab has developed and used the Single Resident Well Model (SRWM) to estimate the ground water activation. Recently, the Concentration Model (CM), a more realistic method which depends on the site hydrogeology has been developed to decide the shielding requirements of the high radiation sites, and to calculate the ground water activation and its subsequent migration to the aquifer. In this report, the concentration of radionuclide released to the surface waters and the aquifer around the MI40 beam absorber are calculated. Subsequently, the ultimate limit on the primary proton beam intensity to be aborted on the Main Injector beam absorber is determined

  7. Performance testing of the LUEhR-40M structure with an accelerated beam

    International Nuclear Information System (INIS)

    The results of experimental investigation of the prototype of the accelerating structure of the therapeutic linear accelerator of the LUEhR-40M model with an accelerating beam are presented. The accelerating structure is the standing wave biperiodic structure with inner coupling cells of 1.6 m length. The design energy of accelerated electrons equalling 20 MeV (during single electron beam passage through an accelerating structure) is obtained. 60 % of accelerated particles are accumulated in the energy interval of (20±1) MeV at 20 mA pulse current and at 3.6 MW SHF-power at the structure input

  8. The primary attenuation coefficient of a p(66)+Be(40) neutron therapy beam

    International Nuclear Information System (INIS)

    The concept of primary and scattered dose components of a radiotherapy beam is commonly used in radiotherapy planning. Four different methods which have been used for photon beams were applied to determine the primary dose linear attenuation coefficient in water (μo) in a p(66)+Be(40) neutron therapy beam. They were: (a) the extrapolation of measured tissue-maximum ratios to zero field size, (b) linear attenuation measurements, (c) dose measurements in phantom with and without a central axis attenuator, and (d) fitting a central axis kerma model, based on convolution techniques, to measured percentage depth dose data. The μo values obtained agree well with each other and vary between 0.071 cm-1 and 0.075 cm-1. (author)

  9. Effects of calcium phosphate coating to SLA surface implants by the ion-beam-assisted deposition method on self-contained coronal defect healing in dogs

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the healing of self-contained coronal defects on a sand-blasted, large-grit, acid-etched (SLA) surface implant, which had a calcium phosphate (CaP) coating applied by ion-beam-assisted deposition (IBAD). We also evaluated the effect of heating the coating to different temperatures. The CaP-coated SLA implants exhibited a slightly larger bone healing capacity in the self-contained coronal defect than SLA implants, indicating that combining SLA surface implants and a CaP coating by the IBAD method had synergistic effects on bone healing. There was no difference in the healing capacity between 350 deg. C and 450 deg. C heat treatment of the coating layer.

  10. Effects of calcium phosphate coating to SLA surface implants by the ion-beam-assisted deposition method on self-contained coronal defect healing in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Heun-Joo; Song, Ji-Eun; Um, Yoo-Jung; Chae, Gyung Joon; Jung, Ui-Won; Kim, Chang-Sung; Choi, Seong-Ho [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Chung, Sung-Min [Dentium Co., Seoul (Korea, Republic of); Lee, In-Seop, E-mail: shchoi726@yuhs.a [Institute of Physics and Applied Physics, Atomic-scale Surface Science Research Center, Yonsei University, Seoul (Korea, Republic of)

    2009-08-15

    The aim of this study was to evaluate the healing of self-contained coronal defects on a sand-blasted, large-grit, acid-etched (SLA) surface implant, which had a calcium phosphate (CaP) coating applied by ion-beam-assisted deposition (IBAD). We also evaluated the effect of heating the coating to different temperatures. The CaP-coated SLA implants exhibited a slightly larger bone healing capacity in the self-contained coronal defect than SLA implants, indicating that combining SLA surface implants and a CaP coating by the IBAD method had synergistic effects on bone healing. There was no difference in the healing capacity between 350 deg. C and 450 deg. C heat treatment of the coating layer.

  11. A model for quantitative correction of coronary calcium scores on multidetector, dual source, and electron beam computed tomography for influences of linear motion, calcification density, and temporal resolution : A cardiac phantom study

    NARCIS (Netherlands)

    Greuter, M. J. W.; Groen, J. M.; Nicolai, L. J.; Dijkstra, H.; Oudkerk, M.

    2009-01-01

    Purpose: The objective of this study is to quantify the influence of linear motion, calcification density, and temporal resolution on coronary calcium determination using multidetector computed tomography (MDCT), dual source CT (DSCT), and electron beam tomography (EBT) and to find a quantitative me

  12. Electron beam CT versus 16-slice spiral CT: how accurately can we measure coronary artery calcium volume?

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate how accurately CAC volume we can be measured using electron beam computed tomography (CT) and 16-slice spiral CT. CAC models with known volume attached to a cardiac phantom were scanned. The error of measurement, variability between measured and real volumes, and inter-scan measurement variability were obtained. For spiral CT, seven different parameters were included: (1) slice thickness (0.625 mm, 1.25 mm and 2.5 mm), (2) retrospective spiral electrocardiograph (ECG)-gated or prospective axial ECG-triggering, (3) overlapping or non-overlapping. The error of measurement was 15% on electron beam CT and 8-20% on spiral CT. CAC volumes were underestimated in 92% and overestimated in 8% of the electron beam CT scans. Volumes were underestimated in 79%, correct in 5% and overestimated in 16% of the spiral CT scans. The best measurement and the least variability was observed on 0.625-mm retrospective spiral ECG-gated CT (error of 8%), a significant result (t-test: P<0.01) when compared with electron beam CT. CAC volume measurement on CT scanners may be significantly different and often underestimates the real volume of CAC. For precise evaluation of CAC volume, thin-slice retrospective spiral ECG-gated scan using a spiral CT scanner is desirable. (orig.)

  13. 40W high beam quality 532nm green laser with LBO intracavity-frequecy-doubling

    Science.gov (United States)

    Liu, Xuesheng; Li, Jing; Liu, Youqiang; Wang, Zhiyong

    2014-12-01

    A high-power high-beam-quality 1064nm Nd:YAG rod laser and SHG by intracavity-frequency-doubling are reported. With two common side-pumped Nd:YAG rod modules in the short cavity, we achieved an 78.5W near diffraction-limited pulsed wave 1064nm laser(M2=1.5) with pulse frequency 30kHz, pulse width 94ns and a good power stability of +/-1% for over two hours. Finally, a 40W pulsed green laser with pulse width of 92ns in a near diffraction-limited beam (M2=1.45) is generated using an LBO crystal as the frequency doubler in the cavity.

  14. Note: Effect of hot liner in producing 40,48Ca beam from RIKEN 18-GHz electron cyclotron resonance ion source

    Science.gov (United States)

    Ozeki, K.; Higurashi, Y.; Kidera, M.; Nakagawa, T.

    2015-01-01

    In order to produce a high-intensity and stable 48Ca beam from the RIKEN 18-GHz electron cyclotron resonance ion source, we have begun testing the production of a calcium beam using a micro-oven. To minimize the consumption rate of the material (48Ca), we introduced the "hot liner" method and investigated the effect of the liner on the material consumption rate. The micro-oven was first used to produce the 48Ca beam for experiments in the RIKEN radioisotope beam factory, and a stable beam could be supplied for a long time with low consumption rate.

  15. Total body neutron activation analysis of calcium: calibration and normalisation

    International Nuclear Information System (INIS)

    An irradiation system has been designed, using a neutron beam from a cyclotron, which optimises the uniformity of activation of calcium. Induced activity is measured in a scanning, shadow-shield whole-body counter. Calibration has been effected and reproducibility assessed with three different types of phantom. Corrections were derived for variations in body height, depth and fat thickness. The coefficient of variation for repeated measurements of an anthropomorphic phantom was 1.8% for an absorbed dose equivalent of 13 mSv (1.3 rem). Measurements of total body calcium in 40 normal adults were used to derive normalisation factors which predict the normal calcium in a subject of given size and age. The coefficient of variation of normalised calcium was 6.2% in men and 6.6% in women, with the demonstration of an annual loss of 1.5% after the menopause. The narrow range should make single measurements useful for diagnostic purposes. (author)

  16. In-beam γ-ray spectroscopy of 38,40,42Si

    International Nuclear Information System (INIS)

    Excited states in the nuclei 38,40,42Si have been studied using in-beam γ-ray spectroscopy following multi-nucleon removal reactions to investigate the systematics of excitation energies along the Z=14 isotopic chain. The most probable candidates for the transition from the yrast 4+ state were tentatively assigned among several γ lines newly observed in the present study. The energy ratios between the 21+ and 41+ states were obtained to be 2.09(5), 2.56(5) and 2.93(5) for 38,40,42Si, respectively, indicating a rapid development of deformation in Si isotopes from N=24 to, at least, N=28. (authors)

  17. 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 ...

  18. 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 ...

  19. Beam Effects from an Increase of LINAC Current from 40 ma to 49 Milliamperes

    Energy Technology Data Exchange (ETDEWEB)

    Ray Tomlin

    2002-06-05

    On March 25, 2002 the FNAL Linac had been running at a decreased 40 ma of beam current for some time. Both the 400 MeV Linac and the 8GeV Booster had been tuned to optimum running during that time. Optimum running for the Booster was at 4.1e12 per pulse. Losses at injection and at transition were limiting intensity at the time. By March 26, 2002 the Linac beam current had been increased to 49 ma. The optimum Booster intensity immediately jumped to 4.5e12 per pulse and increased in the next few days to 4.8e12 and 5e12 per pulse. Booster was not retuned until early April when a low-loss 5.0e12 was obtained for stacking operations. Linac current had sagged to 47 ma by then. Measurements were made on the 25th at 40 ma and the 26th and 27th at 49 ma. This is a report and discussion of those measurements.

  20. 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...

  1. Measurements in the beam direction of the 40Ar projectile fragmentation at 44 MeV/A

    International Nuclear Information System (INIS)

    Accurate beam direction measurements (0±3mr) have been performed on the 40Ar projectile fragmentation on a Ni target, at 44 MeV/u, by using the telescopic mode on the double spectrometer LISE at GANIL. Sampling results on Al and Au targets are also presented. Velocity distributions are analysed for fragments of masses from 10 to 45. As expected from a study of the forward angle physics, the presented beam direction measurements (0 deg) and the grazing angle ones (3 deg) exhibit spectacular differences. The most probable velocities are found much closer to the beam one at 0 deg than at 3 deg. The velocity-integrated mass-yields obtained in the beam direction exhibit a regular exponential rise from A ∼ 18 to A ∼ 40. The role of diffraction is to be examined. (author) 24 refs., 13 figs., 2 tabs

  2. Enhanced bone forming ability of SLA-treated Ti coated with a calcium phosphate thin film formed by e-beam evaporation

    International Nuclear Information System (INIS)

    With an electron-beam evaporation process, a calcium phosphate (Ca-P) thin film of ∼500 nm thick was deposited on sand blasted with large grits and acid etched (SLA) Ti without changing the typical morphology of the SLA surface. Dissolution behavior was investigated by measuring the amount of dissolved phosphate ions with ion chromatography after immersing the SLA Ti sample coated with a Ca-P film in 1 ml de-ionized water maintained at 37 0C for different periods of soaking time, and the surface morphology was observed with field emission scanning electron microscopy. The amount of phosphate ions increased quickly right after immersion but began to decrease after 2 days of immersion by redeposition with Ca ions as apatite, and the amount of biomimetic apatite increased with the extended soaking time. The Saos-2 cell was more attached on the coated surface, and the in vivo evaluation was that the Ca-P deposited SLA implant greatly improved the new bone formation ability.

  3. Enhanced bone forming ability of SLA-treated Ti coated with a calcium phosphate thin film formed by e-beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeongil [Restorative Dentistry, School of Dental Medicine, University at Buffalo, NY 14214 (United States); Choi, Seong-Ho [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, Seoul 120-752 (Korea, Republic of); Chung, Sung-Min; Li, Long-Hao [Dentium Clinic Implantium Institute, Seoul 135-879 (Korea, Republic of); Lee, In-Seop, E-mail: inseop@yonsei.ac.k [Atomic-Scale Surface Science Research Center, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2010-08-01

    With an electron-beam evaporation process, a calcium phosphate (Ca-P) thin film of {approx}500 nm thick was deposited on sand blasted with large grits and acid etched (SLA) Ti without changing the typical morphology of the SLA surface. Dissolution behavior was investigated by measuring the amount of dissolved phosphate ions with ion chromatography after immersing the SLA Ti sample coated with a Ca-P film in 1 ml de-ionized water maintained at 37 {sup 0}C for different periods of soaking time, and the surface morphology was observed with field emission scanning electron microscopy. The amount of phosphate ions increased quickly right after immersion but began to decrease after 2 days of immersion by redeposition with Ca ions as apatite, and the amount of biomimetic apatite increased with the extended soaking time. The Saos-2 cell was more attached on the coated surface, and the in vivo evaluation was that the Ca-P deposited SLA implant greatly improved the new bone formation ability.

  4. Electron beam welding of flanges with tubular shafts of steel 40KhNMA

    International Nuclear Information System (INIS)

    The results are presented of elaborating the technological process for the electron beam welding of flanges with a tube of the 40KhNMA steel and of investigation into the quality of the welded joints. A welded piece has been fabricated conforming to the technology suggested observing the parameters worked-out in the following sequence: assembling the piece; pre-welding of the edges in some points; welding; high tempering; welds quality control; removal of the seam reinforcement inside of the tube and the weld root to the depth of 2 mm; quenching; tempering; welds quality control; finishing. The welds quality control consists in visual inspection, ultrasonic testing, magnetic flaw detection, as well as X-ray and metallographic analyses. The mechanical properties are studied on notched samples cut out of the welded joints. The test results have shown that the mechanical properties of the welded joints meet the requirements on the same level with the base metal

  5. CALCIUM SIGNALING, ION CHANNELS AND MORE: THE DT40 SYSTEM AS A MODEL OF VERTEBRATE ION HOMEOSTASIS AND CELL PHYSIOLOGY

    OpenAIRE

    Perraud, Anne-Laure; Schmitz, Carsten; Scharenberg, Andrew M.

    2006-01-01

    The DT40 B-lymphocyte cell line is a chicken bursal lymphocyte tumor cell line which grows rapidly, expresses a variety of types of constitutive and signal dependent ion transport systems., and supports the efficient use of stable and conditional genetic manipulations. Below, we review the use of DT40 cells in dissecting molecular mechanisms involved in Ca2+, Mg2+, and Zn2+ transport physiology. These studies highlight the flexibility and advantages the DT40 environment offers to investigator...

  6. Single atom detection of calcium isotopes by atom trap trace analysis

    CERN Document Server

    Hoekstra, S; Morgenstern, R; Wilschut, H W; Hoekstra, R

    2005-01-01

    We demonstrate a combination of an isotopically purified atom beam and a magneto-optical trap which enables the single atom detection of all stable isotopes of calcium (40, 42, 43, 44, 46 and 48). These isotopes range in abundance from 96.9 % (40Ca) to 0.004 (46Ca). The trap is loaded from an atomic beam which is decelerated in a Zeeman slower and subsequently deflected over an angle of 30 degrees by optical molasses. The isotope selectivity of the Zeeman slower and the deflection stage is investigated experimentally and compared with Monte Carlo simulations.

  7. Fragmentation Cross Sections of Medium-Energy 35Cl, 40Ar, and 48TiBeams on Elemental Targets

    Energy Technology Data Exchange (ETDEWEB)

    Zeitlin, C.; Guetersloh, S.; Heilbronn, L.; Miller, J.; Fukumura,A.; Iwata, Y.; Murakami, T.; Sihver, L.; Mancusi, D.

    2007-12-08

    Charge-changing and fragment production cross sections at 0degrees have been obtained for interactions of 290, 400, and 650MeV/nucleon 40Ar beams, 650 and 1000 MeV/nucleon 35Cl beams, and a 1000MeV/nucleon 48Ti beam. Targets of C, CH2, Al, Cu, Sn, and Pb were used.Using standard analysis methods, we obtain fragment cross sections forcharges as low as 8 for Cl and Ar beams, and as low as 10 for the Tibeam. Using data obtained with small-acceptance detectors, we reportfragment production cross sections for charges as low as 5, corrected foracceptance using a simple model of fragment angular distributions. Withthe lower-charged fragment cross sections, we cancompare the data topredictions from several models (including NUCFRG2, EPAX2, and PHITS) ina region largely unexplored in earlier work. As found in earlier workwith other beams, NUCFRG2 and PHITS predictions agree reasonably wellwith the data for charge-changing cross sections, but do not accuratelypredict the fragment production cross sections. The cross sections forthe lightest fragments demonstrate the inadequacy of several models inwhich the cross sections fall monotonically with the charge of thefragment. PHITS, despite not agreeing particularly well with the fragmentproduction cross sections on average, nonetheless qualitativelyreproduces somesignificant features of the data that are missing from theother models.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-01-01

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

  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. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Science.gov (United States)

    2010-07-01

    ...-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721...-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium... identified as D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium...

  11. Light particle coincidences with gross structure in energy spectra from the 40Ca+40Ca collision

    International Nuclear Information System (INIS)

    Angular correlations between light charged particles and heavy ion fragments from the 40Ca + 40Ca collision have been investigated. The high excitation energy structure previously observed in inclusive experiments is strongly populated in coincidence with protons for calcium and potassium fragments, with alphas for argon fragments. Particles emitted in coincidence with the structure are strongly focused and have a velocity close to the velocity of the beam, whereas the yield of evaporation decay is very small

  12. Calcium and Cancer Prevention: Strengths and Limits of the Evidence

    Science.gov (United States)

    ... calcium carbonate has about 40 percent elemental calcium, meaning that 500 mg of calcium carbonate actually contains ... in this trial also contained vitamin D (400 international units [ IU ]). During ... and calcium in relation to prostate cancer risk among more than 142, ...

  13. 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 ...

  14. 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...

  15. 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 ...

  16. Comparative testing of transmission Si detectors with an 40Ar beam (33 MeV/A)

    International Nuclear Information System (INIS)

    Seven available current fabrication detectors, which are 300 μm thick, have been tested in the reaction chamber ''Cyrano'', the detected particles are Argon 40 ions (33 MeV/A), elastically scattered on a natural lead target

  17. 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 ...

  18. A cardiac phantom study on quantitative correction of coronary calcium score on multi-detector, dual source, and electron beam tomography for velocity, calcification density, and acquisition time

    Science.gov (United States)

    Greuter, Marcel J. W.; Groen, Jaap M.; Nicolai, Lieuwe J.; Dijkstra, Hildebrand; Oudkerk, Matthijs

    2009-02-01

    Objective: To quantify the influence of velocity, calcification density and acquisition time on coronary calcium determination using multi-detector CT, dual-source CT and EBT. Materials and Methods: Artificial arteries with four calcifications of increasing density were attached to a robotic arm to which a linear movement was applied between 0 and 120 mm/s (step 10 mm/s). The phantom was scanned five times on 64-slice MDCT, DSCT and EBT using a standard acquisition protocol and the average Agatston score was determined. Results: Increasing motion artifacts were observed at increasing velocities on all scanners, with increasing severity from EBT to DSCT to 64-slice MDCT. The Agatston score showed a linear dependency on velocity from which a correction factor was derived. This correction factor showed a linear dependency on calcification density (0.92density of individual calcifications. The dependency of the Agatston score on velocity shows a linear behaviour on calcification density. A quantitative method could be derived which corrects the measured calcium score for the influence of velocity, calcification density and acquisition time.

  19. 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. ...

  20. 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 ...

  1. 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 ...

  2. The readout of the LHC beam luminosity monitor Accurate shower energy measurements at a 40 MHz repetition rate

    CERN Document Server

    Manfredi, P F; Speziali, V; Traversi, G; Manghisoni, M; Re, V; Denes, P; Placidi, Massimo; Ratti, A; Turner, W C; Datte, P S; Millaud, J E

    2004-01-01

    The LHC beam luminosity monitor is based on the following principle. The neutrals that originate in LHC at every PP interaction develop showers of minimum ionizing particles in the absorbers placed in front of the separation dipoles. The shower energy, measured by suitable detectors in the absorbers is proportional to the number of neutral particles and, therefore, to the luminosity. The principle lends itself to a luminosity measurement on a bunch-by-bunch basis. However, to make such a measurement feasible, the system must comply with extremely stringent requirements. Its speed of operation must match the 40 MHz bunch repetition rate of LHC. Besides, the detector must stand extremely high radiation doses. This paper discusses the solutions adopted to comply with these requirements.

  3. Visualizing calcium responses to acetylcholine convection along endothelium of arteriolar networks in Cx40BAC-GCaMP2 transgenic mice

    OpenAIRE

    Bagher, Pooneh; Davis, Michael J.; Segal, Steven S.

    2011-01-01

    Acetylcholine evokes endothelium-dependent vasodilation subsequent to a rise in intracellular calcium. Despite widespread application in human and animal studies, calcium responses to intravascular ACh have not been visualized in vivo. Microiontophoresis of ACh in tissue adjacent to an arteriole activates abluminal muscarinic receptors on endothelial cells within a “local” region of diffusion, but it is unknown whether ACh released in such fashion gains access to the flow stream resulting in ...

  4. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

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

    1984-01-01

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

  5. Ablation depth control with 40 nm resolution on ITO thin films using a square, flat top beam shaped femtosecond NIR laser

    Science.gov (United States)

    Kim, Hoon-Young; Yoon, Ji-Wook; Choi, Won-Suk; Kim, Kwang-Ryul; Cho, Sung-Hak

    2016-09-01

    We reported on the ablation depth control with a resolution of 40 nm on indium tin oxide (ITO) thin film using a square beam shaped femtosecond (190 fs) laser (λp=1030 nm). A slit is used to make the square, flat top beam shaped from the Gaussian spatial profile of the femtosecond laser. An ablation depth of 40 nm was obtained using the single pulse irradiation at a peak intensity of 2.8 TW/cm2. The morphologies of the ablated area were characterized using an optical microscope, atomic force microscope (AFM), and energy dispersive X-ray spectroscopy (EDS). Ablations with square and rectangular types with various sizes were demonstrated on ITO thin film using slits with varying x-y axes. The stereo structure of the ablation with the depth resolution of approximately 40 nm was also fabricated successfully using the irradiation of single pulses with different shaped sizes of femtosecond laser.

  6. Binding of calcium and carbonate to polyacrylates.

    Science.gov (United States)

    Tribello, Gareth A; Liew, CheeChin; Parrinello, Michele

    2009-05-21

    Polyacrylate molecules can be used to slow the growth of calcium carbonate. However, little is known about the mechanism by which the molecules impede the growth rate. A recent computational study (Bulo et al. Macromolecules 2007, 40, 3437) used metadynamics to investigate the binding of calcium to polyacrylate chains and has thrown some light on the coiling and precipitation of these polymers. We extend these simulations to examine the binding of calcium and carbonate to polyacrylate chains. We show that calcium complexed with both carbonate and polyacrylate is a very stable species. The free energies of calcium-carbonate-polyacrylate complexes, with different polymer configurations, are calculated, and differences in the free energy of the binding of carbonate are shown to be due to differences in the amount of steric hindrance about the calcium, which prevents the approach of the carbonate ion. PMID:19400592

  7. Pulse compression below 40fs at 1μm: The first step towards a short-pulse, high-energy beam line at LULI

    Science.gov (United States)

    Chen, Xiaowei; Zou, Jiping; Martin, Luc; Simon, Francois; Lopez-Martens, Rodrigo; Audebert, Patrick

    2010-08-01

    We present the upgrading project ELFIE (Equipement Laser de Forte Intensité et Energie) based on the "100TW" mixed Nd:glass CPA laser system at 1μm at LULI, which includes an energy enhancement and the development of a short-pulse, high-energy, good temporal contrast beam line (50fs/5J). We report the first experimental step towards the short-pulse, high-energy beam line: spectral broadening above 60nm from 7nm and temporal pulse compression below 40fs from 300fs at 1μm through a Krypton-filled hollow fiber compressor.

  8. Calcium and caffeine interaction in increased calcium balance in ovariectomized rats

    OpenAIRE

    Sandra Tavares da Silva; Neuza Maria Brunoro Costa; Frederico Souzalima Caldoncelli Franco; Antônio José Natali

    2013-01-01

    OBJECTIVE: This study investigated the effects of caffeine intake associated with inadequate or adequate calcium intake in laparotomized or ovariectomized rats by means of the calcium balance. Forty adults Wistar rats were ovariectomized or laparotomized. METHODS: The animals (n=40) were randomly placed in eight groups receiving the AIN-93 diet with 100% or 50% of the recommended calcium intake with or without added caffeine (6mg/kg/day). The animals were kept in individuals metabolic cages a...

  9. 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 ...

  10. 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 ...

  11. 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 ...

  12. 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 ...

  13. 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 ...

  14. 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 ...

  15. Fragmentation and direct transfer reactions for 40Ar incident beam on 27Al target at 1760 MeV

    International Nuclear Information System (INIS)

    Peripheral collision studies performed with 40Ar projectiles at 44 MeV/A and 27Al target show that both fragmentation and transfer reactions can be discerned in this type of interaction. The experimental observation of fragments with masses charges and velocities close to those of the incident beam are the signature of transfer reactions and a detailed analysis of the energy spectra of such fragments has been carried out and interpreted in terms of a direct diffraction transfer model. On the other hand, for large mass transfer reactions, abrasion is the suitable mechanism. Inclusive fragment measurement together with the appropriate residual nuclei-fragment coincidence results then provides experimental data in good agreement with the theoretical predictions obtained from a participant spectator model. These investigations also indicate that the separation energies of the participant from the spectator nucleus, at least within the framework of the above model, can be interpreted in terms of a friction force which becomes more efficient as the projectile energy decreases. (author)

  16. Beam-Beam Effects

    OpenAIRE

    Herr, W; Pieloni, T.

    2016-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities.

  17. Beam-Beam Effects

    CERN Document Server

    Herr, W

    2014-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities.

  18. Design, fabrication and VNA testing of an auto-focussing buncher section for 40 keV, 500 mA DC electron beam injection

    International Nuclear Information System (INIS)

    A buncher section for the 40 keV, DC electron beam has been designed in such a way so that it will act as a buncher and focuser to the injected electron beam. The autofocussing effect is obtained by introducing a slow rise of the Eacc in the first buncher cell. The RF phase focusing force is proportional to the factor (βγ2)-1 and it damps out very quickly as the particle becomes relativistic. Taking this dependency into account, the field asymmetry is introduced only in the first bunching cavity. This paper presents the electromagnetic (EM) design of the RF structure, beam dynamics, fabrication and the measurements of the EM parameters with VNA. (author)

  19. Cold and Slow Molecular Beam

    OpenAIRE

    Rasmussen, Julia; Patterson, Dave; Lu, Hsin-I; Wright, Matthew; Doyle, John M.

    2011-01-01

    Employing a two-stage cryogenic buffer gas cell, we produce a cold, hydrodynamically extracted beam of calcium monohydride molecules with a near effusive velocity distribution. Beam dynamics, thermalization and slowing are studied using laser spectroscopy. The key to this hybrid, effusive-like beam source is a “slowing cell” placed immediately after a hydrodynamic, cryogenic source [Patterson et al., J. Chem. Phys., 2007, 126, 154307]. The resulting CaH beams are created in two regimes. In on...

  20. 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 ...

  1. Contribution of intracellular calcium and pH in ischemic uncoupling of cardiac gap junction channels formed of connexins 43, 40, and 45: a critical function of C-terminal domain.

    Directory of Open Access Journals (Sweden)

    Giriraj Sahu

    Full Text Available Ischemia is known to inhibit gap junction (GJ mediated intercellular communication. However the detail mechanisms of this inhibition are largely unknown. In the present study, we determined the vulnerability of different cardiac GJ channels formed of connexins (Cxs 43, 40, and 45 to simulated ischemia, by creating oxygen glucose deprived (OGD condition. 5 minutes of OGD decreased the junctional conductance (Gj of Cx43, Cx40 and Cx45 by 53±3%, 64±1% and 85±2% respectively. Reduction of Gj was prevented completely by restricting the change of both intracellular calcium ([Ca(2+]i and pH (pHi with potassium phosphate buffer. Clamping of either [Ca(2+]i or pHi, through BAPTA (2 mM or HEPES (80 mM respectively, offered partial resistance to ischemic uncoupling. Anti-calmodulin antibody attenuated the uncoupling of Cx43 and Cx45 significantly but not of Cx40. Furthermore, OGD could reduce only 26±2% of Gj in C-terminus (CT truncated Cx43 (Cx43-Δ257. Tethering CT of Cx43 to the CT-truncated Cx40 (Cx40-Δ249, and Cx45 (Cx45-Δ272 helped to resist OGD mediated uncoupling. Moreover, CT domain played a significant role in determining the junction current density and plaque diameter. Our results suggest; OGD mediated uncoupling of GJ channels is primarily due to elevated [Ca(2+]i and acidic pHi, though the latter contributes more. Among Cx43, Cx40 and Cx45, Cx43 is the most resistant to OGD while Cx45 is the most sensitive one. CT of Cx43 has major necessary elements for OGD induced uncoupling and it can complement CT of Cx40 and Cx45.

  2. Prestress Loss and Bending Capacity of Pre-cracked 40 Year-Old PC Beams Exposed to Marine Environment

    Directory of Open Access Journals (Sweden)

    Dasar Amry

    2016-01-01

    Full Text Available Six prestressed concrete beams (PC beam were used for evaluation, consist of four post-tension beams (PC-O and two pre-tension beams (PC-R. In order to investigate the effect of crack on prestress loss and bending capacity after long-term exposed, prestressed concrete beams were pre-crack and then exposed to marine environment. Experimental work was carried out to evaluate PC beams performance after long-term exposed. In addition, visual observations and load bearing capacity test was carried out. Furthermore, evaluation of prestress loss conducted using three-point loading bending test and the remaining tendon forces in the beam were determined using Crack Re-opening Method. The experimental results revealed that prestress loss was increased due to corrosion of strand/wire which affected by the pre-crack on the prestressed beams. Approximately a prestress loss around 26% and 30% was recorded for post-tension and pre-tension beams respectively.

  3. 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...

  4. Calcium score of small coronary calcifications on multidetector computed tomography

    DEFF Research Database (Denmark)

    Groen, J M; Kofoed, K F; Zacho, M;

    2013-01-01

    Multi detector computed tomography (MDCT) underestimates the coronary calcium score as compared to electron beam tomography (EBT). Therefore clinical risk stratification based on MDCT calcium scoring may be inaccurate. The aim of this study was to assess the feasibility of a new phantom which...

  5. Study of the new CSAR62 positive tone electron-beam resist at 40 keV electron energy

    Science.gov (United States)

    Andok, R.; Bencurova, A.; Vutova, K.; Koleva, E.; Nemec, P.; Hrkut, P.; Kostic, I.; Mladenov, G.

    2016-03-01

    One of the few "top-down" methods for nano-device fabrication is the electron-beam lithography, which allows flexible patterning of various structures with a nanoscale resolution down to less than 10 nm. Thinner, more etching durable, and more sensitive e-beam resists are required for the better control, linearity, and uniformity of critical dimensions of structures for nano-device fabrication. Within the last decade, researchers have made significant efforts to improve the resolution of the nanoscale e-beam lithography. The resist material properties are an important factor governing the resolution. Only the e-beam resist ZEP 520 of the Japanese manufacturer ZEON is characterized by relatively good properties and thus meets most users' expectations. This paper deals with the investigation and simulation of the characteristics of the new less-expensive AR-P 6200 (CSAR 62) positive e-beam resist (available since May 2013, manufactured by Allresist GmbH company).

  6. 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 ...

  7. 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 ...

  8. 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 ...

  9. 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 ...

  10. 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

  11. 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.

  12. 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

  13. Beam-beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, A.

    1994-12-01

    The term beam-beam effects is usually used to designate different phenomena associated with interactions of counter-rotating beams in storage rings. Typically, the authors speak about beam-beam effects when such interactions lead to an increase of the beam core size or to a reduction of the beam lifetime or to a growth of particle`s population in the beam halo and a correspondent increase of the background. Although observations of beam-beam effects are very similar in most storage rings, it is very likely that every particular case is largely unique and machine-dependent. This constitutes one of the problems in studying the beam-beam effects, because the experimental results are often obtained without characterizing a machine at the time of the experiment. Such machine parameters as a dynamic aperture, tune dependencies on amplitude of particle oscillations and energy, betatron phase advance between the interaction points and some others are not well known, thus making later analysis uncertain. The authors begin their discussion with demonstrations that beam-beam effects are closely related to non linear resonances. Then, they will show that a non linearity of the space charge field is responsible for the excitation of these resonances. After that, they will consider how beam-beam effects could be intensified by machine imperfections. Then, they will discuss a leading mechanism for the formation of the beam halo and will describe a new technique for beam tails and lifetime simulations. They will finish with a brief discussion of the coherent beam-beam effects.

  14. Coronary artery calcium score using electron beam tomography in the patients with acute obstructive coronary arterial disease : comparative study within asymptomatic high-risk group of atherosclerosis and chronic obstructive coronary arterial disease group

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Seok Jong; Choi, Byoung Wook; Choe, Kyu Ok [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    2001-04-01

    To compare, through analysis of the coronary artery calcium (CAC) score and the risk factors for atherosclerosis, the characteristics of acute coronary syndrome between an asymptomatic high-risk group of atherosclerosis patients and a chronic coronary arterial obstructive disease(CAOD) group. The CAC scores of an asymptomatic high-risk group of atherosclerosis patients (group I, n=284), a chronic CAOD croup (group II, n=39) and an acute coronary syndrome group (group III, n=21) were measured by electron beam tomography. Forty-seven patients with CAOD from groups II and III underwent coronary angiography, and we scrutinized age, sex and risk factors including diabetes mellitus, hypertension, obesity, smoking, hypercholesterolemia and low high-density lipoproteinemia. The numbers of stenotic coronary arterial branches and degree of stenosis revealed by coronary angiography were also recorded. We determined the differences between the three groups in terms of CAC score and the risk factors, the relationship between CAC score and risk factors, and the characteristic features of each type of CAOD group. The mean CA score of group III (135.1) was not statistically different from that of group I (135.7) or group II (365.8). Among patients aged below 50, the mean CAC score of group III (127.4) was significantly higher than that of group I (6.2), (p=0.0006). The mean CAC score at the sixth decade was also significantly different between group I(81.5) and group II (266.9). The mean age of group III (54.2 years) was significantly lower than that of group I (58.1 years) (p=0.047) and of group II (60.1) (p=0.022). There was significant correlation between the number of stenotic coronary arterial branches and log(CAC +1) (p<.01). The square root of the CAC score and the maximal degree of stenosis was also well correlated (p<.01). There was no difference in the mean number of risk factors among the three groups, though the incidence of smoking in group III was significantly

  15. Coronary artery calcium score using electron beam tomography in the patients with acute obstructive coronary arterial disease : comparative study within asymptomatic high-risk group of atherosclerosis and chronic obstructive coronary arterial disease group

    International Nuclear Information System (INIS)

    To compare, through analysis of the coronary artery calcium (CAC) score and the risk factors for atherosclerosis, the characteristics of acute coronary syndrome between an asymptomatic high-risk group of atherosclerosis patients and a chronic coronary arterial obstructive disease(CAOD) group. The CAC scores of an asymptomatic high-risk group of atherosclerosis patients (group I, n=284), a chronic CAOD croup (group II, n=39) and an acute coronary syndrome group (group III, n=21) were measured by electron beam tomography. Forty-seven patients with CAOD from groups II and III underwent coronary angiography, and we scrutinized age, sex and risk factors including diabetes mellitus, hypertension, obesity, smoking, hypercholesterolemia and low high-density lipoproteinemia. The numbers of stenotic coronary arterial branches and degree of stenosis revealed by coronary angiography were also recorded. We determined the differences between the three groups in terms of CAC score and the risk factors, the relationship between CAC score and risk factors, and the characteristic features of each type of CAOD group. The mean CA score of group III (135.1) was not statistically different from that of group I (135.7) or group II (365.8). Among patients aged below 50, the mean CAC score of group III (127.4) was significantly higher than that of group I (6.2), (p=0.0006). The mean CAC score at the sixth decade was also significantly different between group I(81.5) and group II (266.9). The mean age of group III (54.2 years) was significantly lower than that of group I (58.1 years) (p=0.047) and of group II (60.1) (p=0.022). There was significant correlation between the number of stenotic coronary arterial branches and log(CAC +1) (p<.01). The square root of the CAC score and the maximal degree of stenosis was also well correlated (p<.01). There was no difference in the mean number of risk factors among the three groups, though the incidence of smoking in group III was significantly

  16. 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

  17. 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...

  18. Neutron spectra produced by 30, 35 and 40 MeV proton beams at KIRAMS MC-50 cyclotron with a thick beryllium target

    Science.gov (United States)

    Shin, Jae Won; Bak, Sang-In; Ham, Cheolmin; In, Eun Jin; Kim, Do Yoon; Min, Kyung Joo; Zhou, Yujie; Park, Tae-Sun; Hong, Seung-Woo; Bhoraskar, V. N.

    2015-10-01

    Neutrons over a wide range of energies are produced by bombarding a 1.05 cm thick beryllium target with protons of different energies delivered by the MC-50 Cyclotron of the Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux Φ(En) versus neutron energy En, produced by protons of 30, 35, and 40 MeV energies, was obtained by using the GEANT4 code with a data-based hadronic model. For the experimental validation of the simulated neutron spectra, a number of pure aluminum and iron oxide samples were irradiated with the neutrons produced by 30, 35, and 40 MeV protons at 20 μA beam current. The gamma-ray activities of 24Na and 56Mn produced, respectively, through 27Al(n,α)24Na and 56Fe(n,p)56Mn reactions were measured by a HPGe detector. The neutron flux Φ(En) at each neutron energy from the simulation was multiplied with the evaluated cross-sections σ(En) of the respective nuclear reaction, and the summation ∑ Φ(En) σ(En) was calculated over the neutron spectrum for each proton energy of 30, 35, and 40 MeV. The measured gamma-ray activities of 24Na and 56Mn were found in good agreement with the activities estimated by using the summed values of ∑ Φ(En) σ(En) along with other parameters in a neutron activation method.

  19. 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...

  20. 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

  1. Protein kinase C interaction with calcium: a phospholipid-dependent process.

    LENUS (Irish Health Repository)

    Bazzi, M D

    1990-08-21

    The calcium-binding properties of calcium- and phospholipid-dependent protein kinase C (PKC) were investigated by equilibrium dialysis in the presence and the absence of phospholipids. Calcium binding to PKC displayed striking and unexpected behavior; the free proteins bound virtually no calcium at intracellular calcium concentrations and bound limited calcium (about 1 mol\\/mol of PKC) at 200 microM calcium. However, in the presence of membranes containing acidic phospholipids, PKC bound at least eight calcium ions per protein. The presence of 1 microM phorbol dibutyrate (PDBu) in the dialysis buffer had little effect on these calcium-binding properties. Analysis of PKC-calcium binding by gel filtration under equilibrium conditions gave similar results; only membrane-associated PKC bound significant amounts of calcium. Consequently, PKC is a member of what may be a large group of proteins that bind calcium in a phospholipid-dependent manner. The calcium concentrations needed to induce PKC-membrane binding were similar to those needed for calcium binding (about 40 microM calcium at the midpoint). However, the calcium concentration required for PKC-membrane binding was strongly influenced by the phosphatidylserine composition of the membranes. Membranes with higher percentages of phosphatidylserine required lower concentrations of calcium. These properties suggested that the calcium sites may be generated at the interface between PKC and the membrane. Calcium may function as a bridge between PKC and phospholipids. These studies also suggested that calcium-dependent PKC-membrane binding and PKC function could be regulated by a number of factors in addition to calcium levels and diacylglycerol content of the membrane.

  2. Observation of color center peaks in calcium fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, T. [LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, AZ 85287-1704, USA (United States); Garvie, L.A.J. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Rez, P., E-mail: Peter.Rez@asu.edu [Department of Physics, Arizona State University, Tempe, AZ 85287-1504 (United States)

    2015-06-15

    Alkali halides such as calcium fluoride all have color center defects that absorb light in the visible region. Using a moncochromator equipped, aberration corrected, scanning transmission electron microscope (STEM) we recorded spectra showing the time evolution of the generation of F and H centers in calcium fluoride. The final stage of electron beam irradiation is the formation of metallic calcium nanoparticles. High resolution low loss spectra for the Vacuum Ultraviolet region were also recorded. - Highlights: • Color center defects clearly identified by high resolution EELS of CaF{sub 2}. • Both F Centers and H Centers produced by electron beam irradiation. • Ultimately metallic calcium is left as evidenced by plasmon and density of states. • High resolution low loss (VUV) spectra also recorded.

  3. Observation of color center peaks in calcium fluoride

    International Nuclear Information System (INIS)

    Alkali halides such as calcium fluoride all have color center defects that absorb light in the visible region. Using a moncochromator equipped, aberration corrected, scanning transmission electron microscope (STEM) we recorded spectra showing the time evolution of the generation of F and H centers in calcium fluoride. The final stage of electron beam irradiation is the formation of metallic calcium nanoparticles. High resolution low loss spectra for the Vacuum Ultraviolet region were also recorded. - Highlights: • Color center defects clearly identified by high resolution EELS of CaF2. • Both F Centers and H Centers produced by electron beam irradiation. • Ultimately metallic calcium is left as evidenced by plasmon and density of states. • High resolution low loss (VUV) spectra also recorded

  4. STUDY OF SERUM TOTAL CALCIUM, IO NIZED CALCIUM AND TOTAL PROTEIN CONCENTRATIONS IN POSTMENOPAUSAL WOMEN

    Directory of Open Access Journals (Sweden)

    SK.Deepthi

    2015-05-01

    Full Text Available Menopause and ageing is associated with accelerated loss of cortical bone. Osteoporotic fractures are common cause of morbidity and mortality in adult Indian women due to ageing. This study was conducted to evaluate the levels of serum calcium, ionized calcium and total protein levels in postmenopausal women and to assess its relation with ageing. Study includes 70 women (40 post menopausal and 30 prem enopausal women serum alkaline phosphatase, serum calcium, ionized calcium and total proteins, serum albumin were estimated in both cases and controls. There is decrease in serum calcium in postmenopausal; wo men when compared to premenopausal women. There was no significant change in ionized calcium in both cases and controls. ALP is highly significant P<0.001. In postmenopausal women suggesting there is high alkaline phosphotase activity in postmenopausal women as a result of the inhibitory effects of estrogen on bone turnover rate which is dependent on age and body mass index. Decrease in serum albumin was seen in postmenopausal wo men which is the reason for decrease in serum calcium level which is inturn related to ageing effect.

  5. 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...

  6. Growth, grain yield and calcium, potassium and magnesium accumulation in common bean plants as related to calcium nutrition

    Directory of Open Access Journals (Sweden)

    Lucas da Silva Domingues

    2016-04-01

    Full Text Available The objective of this work was to evaluate the plant growth and grain yield characteristics and the accumulation of calcium, potassium and magnesium in the leaves and grains of common bean cultivars grown with different calcium concentrations in the nutrient solution. Two experiments were conducted with nutrient solutions in a soilless system in a greenhouse. In the first experiment, five calcium concentrations (1.10, 1.65, 2.20, 2.75 and 3.30 mmol L-1 and three common bean cultivars (Iraí, BRS Expedito and Carioca were evaluated. Higher calcium concentrations (2.20, 2.75, 3.30, 3.85, 4.40 and 4.95 mmol L-1and two common bean cultivars (BRS Expedito and Carioca were tested in the second experiment. Dry mass of the shoot and root, grain yield and calcium accumulation in the leaves and grains increased linearly in common bean plants supplied with calcium concentrations between 2.20 and 4.95 mmol L-1. The high calcium concentration did not reduce the accumulation of calcium, potassium and magnesium in the leaves and grains. Common bean plants grown with high calcium concentrations present higher dry mass of the shoot and root, high grain yield and high calcium concentration in the leaves and grains.

  7. 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...

  8. 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

  9. 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

  10. Neutron stimulated emission computed tomography applied to the assessment of calcium deposition due to the presence of microcalcifications associated with breast cancer

    International Nuclear Information System (INIS)

    In this paper we presented an application of the Neutron Stimulated Emission Computed Tomography (NSECT), which uses a thin beam of fast neutrons to stimulate stable nuclei in a sample, emitting characteristic gamma radiation. The photon energy is unique and it is used to identify the emitting nuclei. This technique was applied for evaluating the calcium isotopic composition changing due to the development of breast microcalcifications. A particular situation was simulated in which clustered microcalcifications were modeled with diameters less than 1.40 mm. In this case, neutron beam breast spectroscopy was successful in detecting the counting changes in the photon emission spectra for energies, which are characteristics of 40Ca isotope in a low deposited dose rate. (author)

  11. GRP40介导游离脂肪酸对葡萄糖刺激的胰岛素分泌和β细胞内钙离子浓度的变化%GPR40 mediates the effects of FFAs on glucose stimulated insulin secretion and the change of intracellular calcium concentration in pancreatic β cells

    Institute of Scientific and Technical Information of China (English)

    张莹; 程桦; 徐明彤; 张少玲; 黎峰; 杨川; 严励; 李焱

    2009-01-01

    目的 探讨G蛋白耦联受体40(GPR40)是否介导游离脂肪酸(FFAs)短期、长期作用对小鼠胰岛NIT-1 β细胞葡萄糖刺激的胰岛素分泌(GSIS)及胞内钙离子浓度的影响.方法 利用siRNA技术抑制GPR40在NIT-1细胞的表达,ELISA法检测棕榈酸、油酸短期(2 h)、长期(48 h)干预对NIT-1细胞GSIS的影响,激光共聚焦显微镜下观察GSIS过程中细胞内钙离子的变化.结果 FFAs短期干预促进空转染组、对照siRNA转染组GSIS水平(P<0.01),而对GPR40 siRNA组GSIS无明显影响,该组细胞GSIS水平明显低于空转染组和对照siRNA转染组(P<0.01).FFAs长期干预明显抑制空转染组、对照siRNA转染组细胞GSIS水平,对GPR40 siRNA组GSIS无明显影响.空转染组、对照siRNA组GSIS水平低于GPR40siRNA组(P<0.05).激光共聚焦显微镜结果显示,在GSIS过程中,FFAs短期干预后,GPR40 siRNA组胞内钙离子浓度峰值明显低于对照siRNA组(棕榈酸:5.10 vs 7.02,油酸:4.27 vs 6.21,均P<0.05);而FFAs长期干预后,GPR40 siRNA组胞内钙离子浓度峰值明显高于对照siRNA组(棕榈酸:3.24 vs 1.21,油酸:2.83 vs 1.18,均P<0.05).结论 GPR40介导FFAs对GSIS和胞内钙离子浓度变化的短期刺激和长期抑制作用.%Objective To investigate whether G-protein coupled receptor 40(GPR40)mediates short-term and long-term effects of free fatty acids (FFAs) on glucose stimulated insulin secretion (GSIS) and the change of [Ca2+]i in mouse insulinoma NIT-1 cells.Methods The expression of GPR40 in NIT-1 cells was inhibited by siRNA.The short-term and long-term effects of saturated (palmitate) or unsaturated (oleate) fatty acids on GSIS in NIT-1 cells transfected with GPR40 siRNA were examined.Insulin was measured by ELISA.The change in intracellular calcium concentration was observed by laser confocal scanning microscopy after NIT-1 cells were incubated with Fluo-3/AM.Results The short-term treatment of FFAs increased GSIS from NIT-1 cells transfected

  12. Beam Instrumentation and Diagnostics

    CERN Document Server

    Strehl, Peter

    2006-01-01

    This treatise covers all aspects of the design and the daily operations of a beam diagnostic system for a large particle accelerator. A very interdisciplinary field, it involves contributions from physicists, electrical and mechanical engineers and computer experts alike so as to satisfy the ever-increasing demands for beam parameter variability for a vast range of operation modi and particles. The author draws upon 40 years of research and work, most of them spent as the head of the beam diagnostics group at GSI. He has illustrated the more theoretical aspects with many real-life examples that will provide beam instrumentation designers with ideas and tools for their work.

  13. 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...

  14. 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....

  15. AAPM protocol for 40-300 kV x-ray beam dosimetry in radiotherapy and radiobiology

    International Nuclear Information System (INIS)

    The American Association of Physicists in Medicine (AAPM) presents a new protocol, developed by the Radiation Therapy Committee Task Group 61, for reference dosimetry of low- and medium-energy x rays for radiotherapy and radiobiology (40 kV≤tube potential≤300 kV). It is based on ionization chambers calibrated in air in terms of air kerma. If the point of interest is at or close to the surface, one unified approach over the entire energy range shall be used to determine absorbed dose to water at the surface of a water phantom based on an in-air measurement (the 'in-air' method). If the point of interest is at a depth, an in-water measurement at a depth of 2 cm shall be used for tube potentials ≥100 kV (the 'in-phantom' method). The in-phantom method is not recommended for tube potentials <100 kV. Guidelines are provided to determine the dose at other points in water and the dose at the surface of other biological materials of interest. The protocol is based on an up-to-date data set of basic dosimetry parameters, which produce consistent dose values for the two methods recommended. Estimates of uncertainties on the final dose values are also presented

  16. 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)

  17. Calcium scoring using 64-slice MDCT, dual source CT and EBT : a comparative phantom study

    NARCIS (Netherlands)

    Groen, Jaap M.; Greuter, Marcel J. W.; Vliegenthart, R.; Suess, C.; Schmidt, B.; Zijlstra, F.; Oudkerk, M.

    2008-01-01

    Purpose Assessment of calcium scoring (Ca-scoring) on a 64-slice multi-detector computed tomography (MDCT) scanner, a dual-source computed tomography (DSCT) scanner and an electron beam tomography (EBT) scanner with a moving cardiac phantom as a function of heart rate, slice thickness and calcium de

  18. [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

  19. 40 CFR 415.311 - Specialized definitions.

    Science.gov (United States)

    2010-07-01

    ... AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Calcium Hydroxide Production..., the general definitions, abbreviations and methods of analysis set forth in 40 CFR part 401...

  20. Dissolution kinetics of calcium phosphate coatings.

    Science.gov (United States)

    Burke, E M; Lucas, L C

    1998-01-01

    Plasma spray and high velocity oxy-fuel (HVOF) techniques produce coatings with varying composition and amounts of amorphous and crystalline phases. For coatings containing greater amorphous phases, a higher release of calcium ions is evident when samples are placed in Hank's calcium-free balanced salt solutions. Calcium is released from the amorphous phases in the coating, a conclusion that is supported by x-ray powder diffraction (XRD) results. Ion beam sputtering and RF magnetron sputtering under lower energy conditions produce amorphous coatings that will dissolve in a very short time period. When heat treated, crystalline phases are produced in the coatings. Heat-treated coatings are significantly more stable than the amorphous coatings. The dissolution rates of both amorphous and crystalline coatings produced by RF magnetron sputtering have been measured under constant solution conditions at pH 6.50. No reprecipitation is possible under these conditions. The amorphous coating dissolved at a significantly higher rate than the heat-treated coating. Reprecipitation of calcium phosphate onto amorphous coatings is possible in a physiological pH solution. Under these conditions, the dissolution rate of the amorphous coating is four times slower than at the pH 6.50 conditions. PMID:10196809

  1. Effects of a high magnetic field on structure evolution and properties of the molecular beam vapor deposited Fe60Ni40 nanoparticles thin films

    International Nuclear Information System (INIS)

    The Fe60Ni40 (in atomic %) nanoparticles (NPs) thin films with 90 nm thickness were prepared on 25 and 400 °C quartz substrates by using the molecular beam vapor deposition (MBVD) method under a 6 T high magnetic field (HMF). The effects of a HMF on the structure evolution and properties of Fe–Ni thin films were studied by using X-ray diffraction, atomic force microscopy, transmission electron microscopy, vibrating sample magnetometer and four-point probe method. The results show that the crystallinity of thin films is enhanced by a 6 T HMF, and a 6 T HMF changes phase composition of thin films on 25 °C substrate. It is found that the nanoparticle size decreases; the nanoparticle size distribution becomes narrow, and the root mean square (rms) roughness of thin films decreases under a 6 T HMF relative to that without HMF. These lead to the decrease of coercive force, and the increase of in-plane remanence ratio under a 6 T HMF

  2. 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

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

    International Nuclear Information System (INIS)

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

  4. Nonlinear beam-beam resonances

    International Nuclear Information System (INIS)

    Head-on collisions of bunched beams are considered, assuming the two colliding beams have opposite charges. A few experimental observations are described. The single resonance analysis is developed that is applicable to the strong-weak case of the beam-beam interaction. In this case, the strong beam is unperturbed by the beam-beam interaction; motions of the weak beam particles are then analyzed in the presence of the nonlinear electromagnetic force produced by the strong beam at the collision points. The coherent motions of the two coupled strong beams are shown to exhibit distinct nonlinear resonance behavior. 16 refs., 22 figs

  5. Isotopic Anomalies in CP Stars: Helium, Mercury, Platinum, and Calcium

    CERN Document Server

    Cowley, C R; Castelli, F

    2007-01-01

    We review the classical observational results for isotopic abundance variations for several elements in CP stars. We concentrate on the "newest" anomaly, in calcium. The cosmically very rare isotope, Ca-48 can rival and even dominate the more common, alpha nuclide, Ca-40. Relevant examples are found in the hot, non-magnetic HgMn stars, and the field horizontal-branch star, Feige 86. The calcium anomaly is also present in cool, magnetic stars, including the notorious HD 101065, Przybylski's star.

  6. Morphology and electronic structure of nanoscale powders of calcium hydroxyapatite

    OpenAIRE

    Kurgan, Nataly; Karbivskyy, Volodymyr; Kasyanenko, Vasyl

    2015-01-01

    Atomic force microscopy, infrared spectroscopy and NMR studied morphological and physicochemical properties of calcium hydroxyapatite powders produced by changing the temperature parameters of synthesis. Features of morphology formation of calcium hydroxyapatite nanoparticles with an annealing temperature within 200°C to 1,100°C were determined. It is shown that the particle size of the apatite obtained that annealed 700°C is 40 nm corresponding to the particle size of apatite in native bone....

  7. 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)

  8. 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...

  9. Diversity of calcium speciation in leaves of Primulina species (Gesneriaceae

    Directory of Open Access Journals (Sweden)

    Qingwen Qi

    2014-07-01

    Full Text Available Primulina is a genus containing typical “stone plants” or “cave plants” that show a high degree of edaphic specialization in the karst limestone regions of southwest China. Most species of the genus occur only on calcareous soils developed from carbonate bedrock, while a few species are found only on the red soil developed from the Danxia landform or acidic soil developed from sandshale bedrock. The aim of this study is to investigate the diversity and characteristics of calcium absorption and storage in Primulina from different soil substrates. Calcium in leaves was determined for plants sampled from 15 populations representing 11 Primulina species occurring on calcareous soil, red soil or acid soil. We analyzed the main types of calcium found in leaves, and compared the calcium content within and among species from different soil types. The results revealed a general high level of leaf calcium content in Primulina species compared with other plants from the karst regions of southwest China. However, we found a significant difference in calcium content among Primulina species from different soil types, with high average calcium content (2,285.6 mg/kg in Primulina from calcareous soil relative to low levels present in Primulina from both acid soil (1,379.3 mg/kg and Danxia red soil (1,329.1 mg/kg. The main form of calcium stored in most Primulina species (9 out of 11 was pectate calcium, which accounted for 31.6–64.2% of the total calcium in the leaves. In contrast, for two species, P. linearifolia and P. medica, which grow on soil with a pH > 8, the main calcium form was soluble calcium, which accounted for about 40% of the total calcium in plant leaves. In addition, differences in calcium amount and type were recorded within species from either the same or different soil types. These results suggest that there is variation in calcium speciation found in Primulina at both interspecific and intraspecific levels. Our findings provide a

  10. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  11. 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...

  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. Electron beam collimation with a 40 000 tip metallic double-gate field emitter array and in-situ control of nanotip sharpness distribution

    OpenAIRE

    Helfenstein, P.; Guzenko, V.A.; Fink, H W; Tsujino, S

    2013-01-01

    The generation of highly collimated electron beams from a double-gate field emitter array with 40000 metallic tips and large collimation gate apertures is reported. Field emission beam measurements demonstrated the reduction of the beam envelope down to the array size by applying a negative potential to the on-chip gate electrode for the collimation of individual field emission beamlets. Owing to the optimized gate structure, the concomitant decrease of the emission current was minimal, leadi...

  15. 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

  16. 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...

  17. Characterization of a silver-incorporated calcium phosphate film by RBS and its antimicrobial effects

    International Nuclear Information System (INIS)

    A thin calcium phosphate film was synthesized on both commercially pure Ti and Si wafers by electron beam evaporation of hydroxyapatite as an evaporant with simultaneous Ar ion beam bombardments. Silver was introduced into an ion-beam-assisted deposition of a calcium phosphate thin film for antimicrobial effect. The amount of incorporated silver ions was controlled by immersing calcium-phosphate-coated samples in different AgNO3 concentrations, and Rutherford backscattering spectrometry (RBS) was employed to measure the amounts of substituted silver. The higher concentration of silver in the calcium phosphate film was more effective in reducing the bacteria of Escherichia coli ATCC 8739 and Streptococcus mutans OMZ 65 on contact with respect to controls

  18. Characterization of a silver-incorporated calcium phosphate film by RBS and its antimicrobial effects

    Energy Technology Data Exchange (ETDEWEB)

    Han, I-H [Institute of Physics and Applied Physics, and Atomic-Scale Surface Science Research Center, Yonsei University, Seou1 120-749 (Korea, Republic of); Lee, I-S [Institute of Physics and Applied Physics, and Atomic-Scale Surface Science Research Center, Yonsei University, Seou1 120-749 (Korea, Republic of); Song, J-H [Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, M-H [Department of Medical Engineering, Yonsei University, Seoul 120-752 (Korea, Republic of); Park, J-C [Department of Medical Engineering, Yonsei University, Seoul 120-752 (Korea, Republic of); Lee, G-H [Korea Institute of Machinery and Materials, Chang-Won 641-010 (Korea, Republic of); Sun, X-D [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Chung, S-M [Implantium Research Center, Seoul 135-879 (Korea, Republic of)

    2007-09-15

    A thin calcium phosphate film was synthesized on both commercially pure Ti and Si wafers by electron beam evaporation of hydroxyapatite as an evaporant with simultaneous Ar ion beam bombardments. Silver was introduced into an ion-beam-assisted deposition of a calcium phosphate thin film for antimicrobial effect. The amount of incorporated silver ions was controlled by immersing calcium-phosphate-coated samples in different AgNO{sub 3} concentrations, and Rutherford backscattering spectrometry (RBS) was employed to measure the amounts of substituted silver. The higher concentration of silver in the calcium phosphate film was more effective in reducing the bacteria of Escherichia coli ATCC 8739 and Streptococcus mutans OMZ 65 on contact with respect to controls.

  19. 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.

  20. 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....

  1. Bessel Beams

    OpenAIRE

    McDonald, Kirk T

    2000-01-01

    Scalar Bessel beams are derived both via the wave equation and via diffraction theory. While such beams have a group velocity that exceeds the speed of light, this is a manifestation of the "scissors paradox" of special relativty. The signal velocity of a modulated Bessel beam is less than the speed of light. Forms of Bessel beams that satisfy Maxwell's equations are also given.

  2. Electron beam collimation with a 40 000 tip metallic double-gate field emitter array and in-situ control of nanotip sharpness distribution

    Energy Technology Data Exchange (ETDEWEB)

    Helfenstein, P.; Guzenko, V. A.; Tsujino, S. [Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen-PSI (Switzerland); Fink, H.-W. [Physik Institut, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich (Switzerland)

    2013-01-28

    The generation of highly collimated electron beams from a double-gate field emitter array with 40000 metallic tips and large collimation gate apertures is reported. Field emission beam measurements demonstrated the reduction of the beam envelope down to the array size by applying a negative potential to the on-chip gate electrode for the collimation of individual field emission beamlets. Owing to the optimized gate structure, the concomitant decrease of the emission current was minimal, leading to a net enhancement of the current density. Furthermore, a noble gas conditioning process was successfully applied to the double-gate device to improve the beam uniformity in-situ with orders of magnitude increase of the active emission area. The results show that the proposed double-gate field emission cathodes are promising for high current and high brightness electron beam applications such as free-electron lasers and THz power devices.

  3. Electron beam collimation with a 40 000 tip metallic double-gate field emitter array and in-situ control of nanotip sharpness distribution

    Science.gov (United States)

    Helfenstein, P.; Guzenko, V. A.; Fink, H.-W.; Tsujino, S.

    2013-01-01

    The generation of highly collimated electron beams from a double-gate field emitter array with 40000 metallic tips and large collimation gate apertures is reported. Field emission beam measurements demonstrated the reduction of the beam envelope down to the array size by applying a negative potential to the on-chip gate electrode for the collimation of individual field emission beamlets. Owing to the optimized gate structure, the concomitant decrease of the emission current was minimal, leading to a net enhancement of the current density. Furthermore, a noble gas conditioning process was successfully applied to the double-gate device to improve the beam uniformity in-situ with orders of magnitude increase of the active emission area. The results show that the proposed double-gate field emission cathodes are promising for high current and high brightness electron beam applications such as free-electron lasers and THz power devices.

  4. 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...

  5. 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

  6. 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

  7. 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...

  8. 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.

  9. 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.

  10. 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...

  11. 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. The response of one of the radicals decreased with the 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. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Negron M, A.; Ramos B, S.; Camargo R, C. [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Uribe, R. M. [Kent State University, College of Technology, Kent OH (United States); Gomez V, V. [UNAM, Instituto de Quimica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Kobayashi, K., E-mail: negron@nucleares.unam.mx [Yokohama National University (Japan)

    2014-08-15

    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. The response of one of the radicals decreased with the 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. (author)

  13. Beam dumping at ISABELLE

    International Nuclear Information System (INIS)

    Safely ejecting the approx. 40 MJ stored energy per beam at ISABELLE is clearly a major problem, both for experimental apparatus and for superconducting magnets. Intensive study of this problem is just beginning. A brief review of the current status is presented

  14. Calcium and lithium ion production for laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, M.; Palm, K.; Stifler, C.; Steski, D.; Ikeda, S.; Kumaki, M.; Kanesue, T.

    2015-08-23

    Calcium and lithium ion beams are required by NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) to simulate the effects of cosmic radiation. To find out difficulties to provide such high reactive material as laser targets, the both species were experimentally tested. Plate-shaped lithium and calcium targets were fabricated to create ablation plasmas with a 6ns, 1064nm Nd:YAG laser. We found significant oxygen contamination in both the Ca and Li high-charge-state beams due to the rapid oxidation of the surfaces. A large-spot-size, low-power-density laser was then used to analyze the low-charge-state beams without scanning the targets. The low-charge-state Ca beam did not have any apparent oxygen contamination, showing the potential to clean the target entirely with a low-power beam once in the chamber. The Li target was clearly still oxidizing in the chamber after each low-power shot. To measure the rate of oxidation, we shot the low-power laser at the target repeatedly at 10sec, 30sec, 60sec, and 120sec interval lengths, showing a linear relation between the interval time and the amount of oxygen in the beam.

  15. Calcium and lithium ion production for laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, M., E-mail: okamura@bnl.gov [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Palm, K. [Department of Physics, Cornell University, Ithaca, New York 14853-2501 (United States); Stifler, C. [Engineering Physics Systems Department, Providence College, Providence, Rhode Island 02918 (United States); Steski, D.; Kanesue, T. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Ikeda, S. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa (Japan); Kumaki, M. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Research Institute for Science and Engineering, Waseda University, Tokyo (Japan)

    2016-02-15

    Calcium and lithium ion beams are required by NASA Space Radiation Laboratory at Brookhaven National Laboratory to simulate the effects of cosmic radiation. To identify the difficulties in providing such highly reactive materials as laser targets, both species were experimentally tested. Plate shaped lithium and calcium targets were fabricated to create ablation plasmas with a 6 ns 1064 nm neodymium-doped yttrium aluminum garnet laser. We found significant oxygen contamination in both the Ca and Li high charge state beams due to the rapid oxidation of the surfaces. A large spot size, low power density laser was used to create low charge state beams without scanning the targets. The low charge state Ca beam did not have any apparent oxygen contamination, showing the potential to clean the target entirely of oxide with a low power beam once in the chamber. The Li target was clearly still oxidizing in the chamber after each low power shot. To measure the rate of oxidation, we shot the low power laser at the target repeatedly at 10 s, 30 s, 60 s, and 120 s interval lengths, showing a linear relation between the interval time and the amount of oxygen in the beam.

  16. Calcium and lithium ion production for laser ion source

    International Nuclear Information System (INIS)

    Calcium and lithium ion beams are required by NASA Space Radiation Laboratory at Brookhaven National Laboratory to simulate the effects of cosmic radiation. To identify the difficulties in providing such highly reactive materials as laser targets, both species were experimentally tested. Plate shaped lithium and calcium targets were fabricated to create ablation plasmas with a 6 ns 1064 nm neodymium-doped yttrium aluminum garnet laser. We found significant oxygen contamination in both the Ca and Li high charge state beams due to the rapid oxidation of the surfaces. A large spot size, low power density laser was used to create low charge state beams without scanning the targets. The low charge state Ca beam did not have any apparent oxygen contamination, showing the potential to clean the target entirely of oxide with a low power beam once in the chamber. The Li target was clearly still oxidizing in the chamber after each low power shot. To measure the rate of oxidation, we shot the low power laser at the target repeatedly at 10 s, 30 s, 60 s, and 120 s interval lengths, showing a linear relation between the interval time and the amount of oxygen in the beam

  17. Calcium and lithium ion production for laser ion source

    Science.gov (United States)

    Okamura, M.; Palm, K.; Stifler, C.; Steski, D.; Ikeda, S.; Kumaki, M.; Kanesue, T.

    2016-02-01

    Calcium and lithium ion beams are required by NASA Space Radiation Laboratory at Brookhaven National Laboratory to simulate the effects of cosmic radiation. To identify the difficulties in providing such highly reactive materials as laser targets, both species were experimentally tested. Plate shaped lithium and calcium targets were fabricated to create ablation plasmas with a 6 ns 1064 nm neodymium-doped yttrium aluminum garnet laser. We found significant oxygen contamination in both the Ca and Li high charge state beams due to the rapid oxidation of the surfaces. A large spot size, low power density laser was used to create low charge state beams without scanning the targets. The low charge state Ca beam did not have any apparent oxygen contamination, showing the potential to clean the target entirely of oxide with a low power beam once in the chamber. The Li target was clearly still oxidizing in the chamber after each low power shot. To measure the rate of oxidation, we shot the low power laser at the target repeatedly at 10 s, 30 s, 60 s, and 120 s interval lengths, showing a linear relation between the interval time and the amount of oxygen in the beam.

  18. Evaluation of the local hadronic calibration with combined beam-test data for the endcap and forward calorimeters of ATLAS in the pseudorapidity region 2.5<|η|<4.0

    International Nuclear Information System (INIS)

    The local hadronic calibration scheme developed for the reconstruction and calibration of jets and missing transverse energy in ATLAS has been evaluated using data obtained during combined beam tests of modules of the ATLAS liquid argon endcap and forward calorimeters. These tests covered the pseudorapidity range of 2.5<|η|<4.0. The analysis has been performed using special sets of calibration weights and corrections obtained with the GEANT4 simulation of a detailed beam-test setup. The evaluation itself has been performed through the careful study of specific calorimeter performance parameters such as e.g. energy response and resolution, shower shapes, as well as different physics lists of the GEANT4 simulation.

  19. 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...

  20. Assessment of food calcium radioprotection effectiveness against cesium-137, added alone and with iodine-131

    International Nuclear Information System (INIS)

    New fish product with addition of food calcium had radioprotective properties, resulted in decreased cesium-137 content in organs and tissues of animals by 40-60% and lesser changes in differential blood count and biochemical indexes of blood serum

  1. 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...

  2. Relativistic electron beams above thunderclouds

    DEFF Research Database (Denmark)

    Füellekrug, M.; Roussel-Dupre, R.; Symbalisty, E. M. D.;

    2011-01-01

    Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency similar to 40-400 kHz which they radiate. The electron beams occur similar to 2-9 ms after positive cloud-to-ground lightning discharges at heights between similar to 22-72 km above...... thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams of...... electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of similar to 7MeV to transport a total charge of similar to-10mC upwards. The impulsive current similar to 3 x 10(-3) Am-2 associated with relativistic electron beams above thunderclouds is...

  3. Relativistic electron beams above thunderclouds

    Directory of Open Access Journals (Sweden)

    M. Füllekrug

    2011-05-01

    Full Text Available Non-luminous relativistic electron beams above thunderclouds are detected by radio remote sensing with low frequency radio signals from 40–400 kHz. The electron beams occur 2–9 ms after positive cloud-to-ground lightning discharges at heights between 22–72 km above thunderclouds. The positive lightning discharges also cause sprites which occur either above or before the electron beam. One electron beam was detected without any luminous sprite occurrence which suggests that electron beams may also occur independently. Numerical simulations show that the beamed electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of 7 MeV to transport a total charge of 10 mC upwards. The impulsive current associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.

  4. Solid state NMR study calcium phosphate ceramics

    International Nuclear Information System (INIS)

    High-resolution 31P and 1H NMR spectra at 40 and 121 MHz 31P and 300 MHz 1H of synthetic and biological samples of calcium phosphates have been obtained by magic angle spinning (MAS) at spinning speeds up to 6.5 kHz, and high power proton decoupling. The samples include crystalline hydroxyapatite, a deficient hydroxyapatite characterized by a Ca/P atomic ratio of 1.5, a poorly crystallized hydroxyapatite, monetite, brushite, octacalcium phosphate, β-tricalcium phosphate and rabbit femoral bone. The interactions between nuclei in unlike structures and the mobility of acid protons are discussed. (author). 11 refs.; 2 figs.; 1 tab

  5. Scattering lengths of calcium and barium isotopes

    OpenAIRE

    Dammalapati, U.; Willmann, L.; Knoop, S.

    2011-01-01

    We have calculated the s-wave scattering length of all the even isotopes of calcium (Ca) and barium (Ba), in order to investigate the prospect of Bose-Einstein condensation (BEC). For Ca we have used an accurate molecular potential based on detailed spectroscopic data. Our calculations show that Ca does not provide other isotopes alternative to the recently Bose condensed 40Ca that suffers strong losses because of a very large scattering length. For Ba we show by using a model potential that ...

  6. 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.

  7. 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...

  8. 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.

  9. 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...

  10. 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...

  11. Calcium phosphates in Ca(2+)-fortified milk: phase identification and quantification by Raman spectroscopy.

    Science.gov (United States)

    Arifin, Martha; Swedlund, Peter J; Hemar, Yacine; McKinnon, Ian R

    2014-12-17

    Calcium phosphate nanoclusters (CPNs) are important for the structure, function, and nutrient density of many dairy products. Phosphorylated amino acids in caseins stabilize calcium phosphate as nanoclusters which are amorphous to X-ray diffraction and exist within casein micelles, and these CPNs play a key role in micelle stability. Addition of calcium to milk results in further calcium phosphate removal from the serum, and there is uncertainty about the nature of the material formed and its stability. In this work we investigate both the solution and colloidal phases in CaCl2 enriched bovine milk to identify, quantify, and determine the solubility of the calcium phosphate material formed in response to calcium addition to milk. The P-O stretching bands are quite distinct in the Raman spectra of the main synthetic calcium phosphate mineral phases, including the amorphous calcium phosphate phase. In response to adding between 5 and 40 mM CaCl2 to milk, the serum phosphate concentration decreased asymptotically from 7.5 ± 0.2 to 0.54 ± 0.05 mM. Using Raman spectroscopy with a combination of internal and external standards, it was possible to show that the calcium phosphate material formed after Ca(2+) addition to milk was the same as amorphous calcium phosphate nanoclusters present in the absence of added calcium. The use of an internal standard allowed a quantitative analysis of the spectra which demonstrated that the amorphous calcium phosphate formed accounted for all of the calcium and phosphate that was removed from solution in response to calcium addition. PMID:25414967

  12. 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......

  13. 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.

  14. 40 CFR 98.190 - Definition of the source category.

    Science.gov (United States)

    2010-07-01

    .... (a) Lime manufacturing plants (LMPs) engage in the manufacture of a lime product (e.g., calcium oxide, high-calcium quicklime, calcium hydroxide, hydrated lime, dolomitic quicklime, dolomitic hydrate, or... in 40 CFR 63.7081(a)(1). (b) This source category includes all LMPs unless the LMP is located at...

  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. Calcium scoring using 64-slice MDCT, dual source CT and EBT: a comparative phantom study

    OpenAIRE

    Groen, Jaap M.; Greuter, Marcel J. W.; Vliegenthart, R.; Suess, C.; Schmidt, B.; Zijlstra, F.; Oudkerk, M.

    2007-01-01

    Purpose Assessment of calcium scoring (Ca-scoring) on a 64-slice multi-detector computed tomography (MDCT) scanner, a dual-source computed tomography (DSCT) scanner and an electron beam tomography (EBT) scanner with a moving cardiac phantom as a function of heart rate, slice thickness and calcium density. Methods and materials Three artificial arteries with inserted calcifications of different sizes and densities were scanned at rest (0 beats per minute) and at 50–110 beats per minute (bpm) w...

  17. The citotoxicity of calcium hydroxide intracanal dressing by MTT assay

    Directory of Open Access Journals (Sweden)

    Nanik Zubaidah

    2007-12-01

    Full Text Available Calcium hydroxide had been used as the intracanal dressing in endodontic treatment due to its high alkaline and high antimicrobial capacity. It also be able to dissolve the necrotic tissue, prevent the root resorbtion and regenerate a new hard tissue. The aim of this study is to identify the concentration of calcium hydroxide that has the lowest citotoxicity. There are 5 groups, each group had 8 samples with different concentration of calcium hydroxide. Group I: 50%, Group II: 55%, Group III: 60%, Group IV: 65% and Group V: 70%. The citotoxicity test by using enzymatic assay of MTT [3-(4.5- dimethylthiazol-2yl ]-2.5 diphenyl tetrazolium bromide, against fibroblast cell (BHK-21. The result of susceptibility test was showed by the citotoxicity detection of the survive cell of fibroblast that was measured spectrophotometrically using 595 nm beam. The data was analyzed using One-Way ANOVA test with significant difference α = 0.05 and subsequently LSD test. The result showed that in concentration 50%, 55%, 60%, 65%, and 70% calcium hydroxide had low toxicity, but calcium hydroxide 60%, had the lowest toxicity.

  18. 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 ...

  19. 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 ...

  20. 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

  1. 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)

  2. Beam - cavity interaction beam loading

    International Nuclear Information System (INIS)

    The interaction of a beam with a cavity and a generator in cyclic accelerators or storage rings is investigated. Application of Maxwell's equations together with the nonuniform boundary condition allows one to get an equivalent circuit for a beam-loaded cavity. The general equation for beam loading is obtained on the basis of the equivalent circuit, and the beam admittance is calculated. Formulas for power consumption by a beam-loaded cavity are derived, and the optimal tuning and coupling factor are analyzed. (author)

  3. 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...

  4. Analytical models of calcium binding in a calcium channel

    International Nuclear Information System (INIS)

    The anomalous mole fraction effect of L-type calcium channels is analyzed using a Fermi like distribution with the experimental data of Almers and McCleskey [J. Physiol. 353, 585 (1984)] and the atomic resolution model of Lipkind and Fozzard [Biochemistry 40, 6786 (2001)] of the selectivity filter of the channel. Much of the analysis is algebraic, independent of differential equations. The Fermi distribution is derived from the configuration entropy of ions and water molecules with different sizes, different valences, and interstitial voids between particles. It allows us to calculate potentials and distances (between the binding ion and the oxygen ions of the glutamate side chains) directly from the experimental data using algebraic formulas. The spatial resolution of these results is comparable with those of molecular models, but of course the accuracy is no better than that implied by the experimental data. The glutamate side chains in our model are flexible enough to accommodate different types of binding ions in different bath conditions. The binding curves of Na+ and Ca2+ for [CaCl2] ranging from 10−8 to 10−2 M with a fixed 32 mM background [NaCl] are shown to agree with published Monte Carlo simulations. The Poisson-Fermi differential equation—that includes both steric and correlation effects—is then used to obtain the spatial profiles of energy, concentration, and dielectric coefficient from the solvent region to the filter. The energy profiles of ions are shown to depend sensitively on the steric energy that is not taken into account in the classical rate theory. We improve the rate theory by introducing a steric energy that lumps the effects of excluded volumes of all ions and water molecules and empty spaces between particles created by Lennard-Jones type and electrostatic forces. We show that the energy landscape varies significantly with bath concentrations. The energy landscape is not constant

  5. Frozen Beams

    CERN Document Server

    Okamoto, Hiromi

    2005-01-01

    In general, the temperature of a charged particle beam traveling in an accelerator is very high. Seen from the rest frame of the beam, individual particles randomly oscillate about the reference orbit at high speed. This internal kinetic energy can, however, be removed by introducing dissipative interactions into the system. As a dissipative process advances, the beam becomes denser in phase space or, in other words, the emittance is more diminished. Ideally, it is possible to reach a "zero-emittance" state where the beam is Coulomb crystallized. The space-charge repulsion of a crystalline beam just balances the external restoring force provided by artificial electromagnetic elements. In this talk, general discussion is made of coasting and bunched crystalline beams circulating in a storage ring. Results of molecular dynamics simulations are presented to demonstrate the dynamic nature of various crystalline states. A possible method to approach such an ultimate state of matter is also discussed.

  6. 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

  7. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  8. LEDA BEAM DIAGNOSTICS INSTRUMENTATION: BEAM POSITION MONITORS

    International Nuclear Information System (INIS)

    The Low Energy Demonstration Accelerator (LEDA) facility located at Los Alamos National Laboratory (LANL) accelerates protons to an energy of 6.7-MeV and current of 100-mA operating in either a pulsed or cw mode. Of key importance to the commissioning and operations effort is the Beam Position Monitor system (BPM). The LEDA BPM system uses five micro-stripline beam position monitors processed by log ratio processing electronics with data acquisition via a series of custom TMS32OC40 Digital Signal Processing (DSP) boards. Of special interest to this paper is the operation of the system, the log ratio processing, and the system calibration technique. This paper will also cover the DSP system operations and their interaction with the main accelerator control system

  9. 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.

  10. Theoretical evaluation of induced radioactivity in food products by electron or X-ray beam sterilization

    International Nuclear Information System (INIS)

    We evaluate first the energy density for electrons or X-ray beams necessary to produce a reference level of 1 kilogray at the maximum of dose, as a function of energy, for electrons and bremsstrahlung photons, based on experimental data obtained on radio-therapy beams, from 4 to 32 MeV, and irradiation beams from production plant CARIC. Then from the production of neutrons on the tungsten target and from (γn) reactions on the deuterium content of the irradiated food, the slowing down and capture of these neutrons is estimated. Radioisotopes can be produced by (γn) reactions on iodine, and to a lesser extent on tin, lead, barium, etc., but the major contribution is neutron activation, where the more critical elements are sodium, chlorine, potassium, magnesium, phosphorus, calcium. Induced activity is compared to natural activity coming from potassium 40, carbon 14 and radium, contained in all foods. For electrons up to 1 Mrad the induced activity remains of the order of a few percent of natural activity, for energies below 10 to 11 MeV. Bremsstrahlung X-ray irradiations can give comparable levels as soon as the energy of the generating electron beam is above 3 MeV. The induced activity decays within a few days. (author)

  11. Dose-dependent ATP depletion and cancer cell death following calcium electroporation, relative effect of calcium concentration and electric field strength.

    Directory of Open Access Journals (Sweden)

    Emilie Louise Hansen

    Full Text Available Electroporation, a method for increasing the permeability of membranes to ions and small molecules, is used in the clinic with chemotherapeutic drugs for cancer treatment (electrochemotherapy. Electroporation with calcium causes ATP (adenosine triphosphate depletion and cancer cell death and could be a novel cancer treatment. This study aims at understanding the relationship between applied electric field, calcium concentration, ATP depletion and efficacy.In three human cell lines--H69 (small-cell lung cancer, SW780 (bladder cancer, and U937 (leukaemia, viability was determined after treatment with 1, 3, or 5 mM calcium and eight 99 μs pulses with 0.8, 1.0, 1.2, 1.4 or 1.6 kV/cm. Fitting analysis was applied to quantify the cell-killing efficacy in presence of calcium. Post-treatment intracellular ATP was measured in H69 and SW780 cells. Post-treatment intracellular ATP was observed with fluorescence confocal microscopy of quinacrine-labelled U937 cells.Both H69 and SW780 cells showed dose-dependent (calcium concentration and electric field decrease in intracellular ATP (p<0.05 and reduced viability. The 50% effective cell kill was found at 3.71 kV/cm (H69 and 3.28 kV/cm (SW780, reduced to 1.40 and 1.15 kV/cm (respectively with 1 mM calcium (lower EC50 for higher calcium concentrations. Quinacrine fluorescence intensity of calcium-electroporated U937 cells was one third lower than in controls (p<0.0001.Calcium electroporation dose-dependently reduced cell survival and intracellular ATP. Increasing extracellular calcium allows the use of a lower electric field.This study supports the use of calcium electroporation for treatment of cancer and possibly lowering the applied electric field in future trials.

  12. 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.

  13. Beam Instabilities

    CERN Document Server

    Rumolo, G

    2014-01-01

    When a beam propagates in an accelerator, it interacts with both the external fields and the self-generated electromagnetic fields. If the latter are strong enough, the interplay between them and a perturbation in the beam distribution function can lead to an enhancement of the initial perturbation, resulting in what we call a beam instability. This unstable motion can be controlled with a feedback system, if available, or it grows, causing beam degradation and loss. Beam instabilities in particle accelerators have been studied and analysed in detail since the late 1950s. The subject owes its relevance to the fact that the onset of instabilities usually determines the performance of an accelerator. Understanding and suppressing the underlying sources and mechanisms is therefore the key to overcoming intensity limitations, thereby pushing forward the performance reach of a machine.

  14. CT measurement of coronary calcium mass: impact on global cardiac risk assessment

    International Nuclear Information System (INIS)

    Coronary calcium mass percentiles can be derived from electron beam CT as well as from multidetector-row CT of all manufacturers. Coronary calcium mass may serve as a more individualized substitute for age for cardiac risk stratification. The aim was to investigate the potential impact of CT coronary calcium mass quantification on cardiac risk stratification using an adjusted Framingham score. Standardized coronary calcium mass was determined by multidetector-row CT in a total of 1,473 patients (1,038 male, 435 female). The impact on risk stratification of replacing the traditional Framingham age point score by a point score based on calcium mass relative to age was tested. Any coronary calcium found in males in the age group of 20-34 years and females in the age group of 20-59 years results in an increase of the Framingham score by 9 and 4-7 points, respectively. Only in males 65 years of age and older, none or minimal amounts of coronary calcium decrease the Framingham score by three points. The coronary calcium mass and age-related scoring system may have impact on the reassignment of patients with an intermediate Framingham risk to a lower or higher risk group. (orig.)

  15. 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...

  16. Calcium Orthophosphates as Bioceramics: State of the Art

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2010-11-01

    Full Text Available In the late 1960s, much interest was raised in regard to biomedical applications of various ceramic materials. A little bit later, such materials were named bioceramics. This review is limited to bioceramics prepared from calcium orthophosphates only, which belong to the categories of bioactive and bioresorbable compounds. There have been a number of important advances in this field during the past 30–40 years. Namely, by structural and compositional control, it became possible to choose whether calcium orthophosphate bioceramics were biologically stable once incorporated within the skeletal structure or whether they were resorbed over time. At the turn of the millennium, a new concept of calcium orthophosphate bioceramics—which is able to promote regeneration of bones—was developed. Presently, calcium orthophosphate bioceramics are available in the form of particulates, blocks, cements, coatings, customized designs for specific applications and as injectable composites in a polymer carrier. Current biomedical applications include artificial replacements for hips, knees, teeth, tendons and ligaments, as well as repair for periodontal disease, maxillofacial reconstruction, augmentation and stabilization of the jawbone, spinal fusion and bone fillers after tumor surgery. Exploratory studies demonstrate potential applications of calcium orthophosphate bioceramics as scaffolds, drug delivery systems, as well as carriers of growth factors, bioactive peptides and/or various types of cells for tissue engineering purposes.

  17. 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

  18. Vitamin D does not increase calcium absorption in young women: a randomized clinical trial.

    Science.gov (United States)

    Gallagher, J Christopher; Jindal, Prachi S; Smith, Lynette M

    2014-01-01

    It is commonly said that vitamin D should be used to increase calcium absorption. We tested this statement in a dose-response study of vitamin D on calcium absorption. A total of 198 white and African American women, aged 25 to 45 years, with vitamin D insufficiency, serum 25-hydroxyvitamin D (25OHD) ng/mL, were randomized in a double-blind study to vitamin D3 400, 800, 1600, 2400 IU, or placebo. A calcium supplement was given to increase mean calcium intake at baseline from 706 mg/d to 1031 mg/d. Calcium absorption was measured at baseline and after 12 months using a single isotope method with radiocalcium45 and 100 mg of calcium. Mean baseline serum 25OHD was 13.4 ng/mL (33.5 nmol/L) and increased to 40 ng/mL (100 nmol/L) on the highest dose of 2400 IU. Using a multivariate regression analysis with significant predictors, baseline absorption, calcium intake, and weight, there was no increase in 12-month calcium absorption compared with baseline on any dose of vitamin D in either whites or African Americans. There was no significant relationship between 12-month calcium absorption and final serum 25OHD. In an analysis of calcium absorption and serum 25OHD at baseline, serum 25OHD levels were divided into groups: 0 to 5, 6 to 10, 11 to 15, or 16 to 20 ng/mL. There was no evidence of a threshold decrease in calcium absorption or serum 1,25 dihydroxyvitamin D (1,25(OH)2 D) amongst the lowest groups. Vitamin D doses up to 2400 IU daily did not increase calcium absorption. No threshold level of serum 25OHD for calcium absorption was found at baseline or in the longitudinal study, suggesting that active transport of calcium is saturated at very low serum 25OHD levels ng/mL. There is no need to recommend vitamin D for increasing calcium absorption in normal subjects. Very efficient calcium absorption at very low levels of serum 25OHD explains why people do not develop osteomalacia provided that dietary intakes of calcium and phosphorus are adequate. PMID

  19. 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

  20. Binding of [125I]iodipine to parathyroid cell membranes: Evidence of a dihydropyridine-sensitive calcium channel

    International Nuclear Information System (INIS)

    The parathyroid cell is unusual, in that an increase in extracellular calcium concentrations inhibits PTH release. Calcium channels are glycoproteins that span cell membranes and allow entry of extracellular calcium into cells. We have demonstrated that the calcium channel agonist (+)202-791, which opens calcium channels, inhibits PTH release and that the antagonist (-)202-791, which closes calcium channels, stimulates PTH release. To identify the calcium channels responsible for these effects, we used a radioligand that specifically binds to calcium channels. Bovine parathyroid cell membranes were prepared and incubated under reduced lighting with [125I] iodipine (SA, 2000 Ci/mmol), which recognizes 1,4-dihydropyridine-sensitive calcium channels. Bound ligand was separated from free ligand by rapid filtration through Whatman GF/B filters. Nonspecific binding was measured by the inclusion of nifedipine at 10 microM. Specific binding represented approximately 40% of the total binding. The optimal temperature for [125I] iodipine binding was 4 C, and binding reached equilibrium by 30 min. The equilibrium dissociation constant (Kd) was approximately 550 pM, and the maximum number of binding sites was 780 fmol/mg protein. Both the calcium channel agonist (+)202-791 and antagonist (-)202-791 competitively inhibited [125I] iodipine binding, with 50% inhibition concentrations of 20 and 300 nM, respectively. These data indicate the presence of dihydropyridine-sensitive calcium channels on parathyroid cell membranes

  1. 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...

  2. Effect of Electron beam on Prepared HAP-Gel Composition

    Directory of Open Access Journals (Sweden)

    Naima A. El Gendy*,Tawfik M. S.**, and Asma M. Nour

    2014-04-01

    Full Text Available Background: Polyvinyl alcohol liquid PVAl was used as the organic carrier for Hydroxylapatite-gel (Hap-gel composite. PVAl has the ability to form a nano- hydroxylapatite polyvinyl alcohol composite gel which has a wide range of uses in different environmental and medical applications. Prepared Hap-gel is known to have a very similar composition to human bone and is used as a substitute for bones in compound fractures and artificial dentures. Matreia and Methods: In this work prepared HAP- gel was exposed to a high ionizing radiation electron beam (5 kilo Gray and an aqueous solution containing aluminum ions (Al+. Some investigations were done to illustrate the effect of radiation exposure and aluminum contamination on prepared Hap-gel. Results: Energy dispersive X-ray analysis (EDx showed that the electron beam used caused an obvious increase in the calcium ions (Ca++ content of the prepared Hap-gel from 60% to 65.69 % with a prominent decrease in phosphorus ions (P + content from 40 % to 34.31 % in addition to an increase in the Ca/P ratio from 1.5 to 1.91. Exposure of the pre-irradiated Hap-gel samples to aluminium ions (Al+ resulted in a noticeable decrease in Ca++ content from 65.69 atomic % to 32.14 % atomic % and a further noticeable decrease in P+ content from 34.31 % atomic % to 13 atomic % as well as an increase in the Ca/P ratio from 1.91 to 2.47. The levels for the original prepared Hap-gel were Ca++; 60 atomic % and P+; 40 atomic %. It was deduced that exposure of the Hap-gel to Al+ had a further damaging effect on the pre-irradiated Hap-gel composition in addition to the damaging effect that the electron beam used induced on the samples. Conclusions: it could be concluded that electron beams and Al+ have an injurious effect on human bone tissue taking into consideration the similarity in composition between Hap-gel and bones. Therefore, this study could be beneficial in the field of osteoporosis research and assist the

  3. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    Energy Technology Data Exchange (ETDEWEB)

    Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A [Department of Tissue Regeneration, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hedhammar, My; Johansson, Jan [Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, the Biomedical Centre, Box 575, 751 23 Uppsala (Sweden); Blom, Tobias; Leifer, Klaus [Department of Engineering Sciences, Uppsala University, Box 534, S-751 21 Uppsala (Sweden)

    2010-08-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  4. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    International Nuclear Information System (INIS)

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  5. Molecular beams

    International Nuclear Information System (INIS)

    This book is a timeless and rather complete theoretical and experimental treatment of electric and magnetic resonance molecular-beam experiments for studying the radio frequency spectra of atoms and molecules. The theory of interactions of the nucleus with atomic and molecular fields is extensively presented. Measurements of atomic and nuclear magnetic moments, electric multipole moments, and atomic fine and hyperfine structure are detailed. Useful but somewhat outdated chapters on gas kinetics, molecular beam design, and experimental techniques are also included

  6. BEAM applications to polymer materials

    International Nuclear Information System (INIS)

    Recently papers about beam applications to polymers have been increasing rapidly both in the fundamental and applied fields. Fairly large number of papers have been published in the fundamental aspects of radiation effects of beam applications to polymers such as pulse radiolysis and high density electronic excitation effects. A number of papers have been published in the more applied aspects of beam applications to polymers such as radiation processing and curing. The present paper describes recent beam applications to polymers. 1. Radiation Effects on Polymers; Radiation effects on polymers have been studied for more than 40 years. Most of work on radiation effects on polymers has been carried out by using high energy photon (gamma-ray) and electron beams, since polymers are sensitive to any kinds of ionizing radiation. Even non-ionizing radiation such as ultraviolet and visible light excites electronic excited states of polymers and then photo-chemical reactions of polymers are induced from the electronic excited states. Studies on radiation effects of other ionizing radiation on polymers have not been so popular for a long time. Recently application of new radiation such as ion beams to polymers have been worthy of remark in fields of advanced science and technology, since new radiation beams induce different radiation effects from those induced by high energy gamma-rays and electrons. 2. Beam Applications of Polymers; Recent progress in beam applications to polymers such as radiation processing and curing, x-ray and electron beam microlithography, and applications of new beams such as ion beams to polymers has been reviewed. (author)

  7. Velocity distribution measurements in atomic beams generated using laser induced back-ablation

    CERN Document Server

    Denning, A; Lee, S; Ammonson, M; Bergeson, S D

    2008-01-01

    We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a sub-thermal atomic beam.

  8. Calcium isotopes in wine

    Science.gov (United States)

    Holmden, C. E.

    2011-12-01

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

  9. Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

    OpenAIRE

    Ganesan Lavanya; Josephraj Jegan

    2015-01-01

    This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study...

  10. Calcium Orthophosphates as Bioceramics: State of the Art

    OpenAIRE

    Sergey V. Dorozhkin

    2010-01-01

    In the late 1960s, much interest was raised in regard to biomedical applications of various ceramic materials. A little bit later, such materials were named bioceramics. This review is limited to bioceramics prepared from calcium orthophosphates only, which belong to the categories of bioactive and bioresorbable compounds. There have been a number of important advances in this field during the past 30–40 years. Namely, by structural and compositional control, it became possible to choose whet...

  11. "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...

  12. LHC beam instrumentation detectors and acquisition systems

    International Nuclear Information System (INIS)

    An overview of some of the detectors and acquisition systems being developed for measuring and controlling beam parameters in the LHC. The two largest systems concern the measurement of beam position, with over 1000 monitors, and beam loss, with over 3000 monitors. For the beam position system a novel wide band time normaliser has been developed to allow bunch-by-bunch 40MHz acquisitions with a dynamic range greater than 30dB and an overall linearity of better than 1%. Also mentioned will be the acquisition system for the fast beam current transformers and the development of CdTe detectors for luminosity monitoring. [author

  13. 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...

  14. 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 ...

  15. The influence of chronic administration of calcium carbonate on the bioavailability of oral ciprofloxacin.

    OpenAIRE

    Sahai, J; Healy, D P; Stotka, J; Polk, R E

    1993-01-01

    Six healthy male volunteers participated in a two-period, two-treatment study to determine the effect of chronic calcium carbonate administration on ciprofloxacin bioavailability. There was a mean reduction of 40% in Cmax and 43% in AUC when calcium carbonate was administered with ciprofloxacin, compared with ciprofloxacin alone (P < 0.05). There were no changes in either half-life or tmax. It is therefore recommended that patients being treated with ciprofloxacin for serious infections refra...

  16. 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

  17. 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

  18. 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

  19. Early Side Effects of Three-Dimensional Conformal External Beam Accelerated Partial Breast Irradiation to a Total Dose of 40 Gy in One Week (A Phase II Trial)

    Energy Technology Data Exchange (ETDEWEB)

    Bourgier, Celine, E-mail: bourgier@igr.fr [Department of Radiation Oncology, Institut Gustave Roussy, Villejuif (France); Pichenot, Charlotte; Verstraet, Rodolfe [Department of Physics, Institut Gustave Roussy, Villejuif (France); El Nemr, Mohamed; Heymann, Steve [Department of Radiation Oncology, Institut Gustave Roussy, Villejuif (France); Biron, Bruno [Department of Physics, Institut Gustave Roussy, Villejuif (France); Delaloge, Suzette [Department of Breast Oncology, Institut Gustave Roussy, Villejuif (France); Mathieu, Marie-Christine [Department of Pathology, Institut Gustave Roussy, Villejuif (France); Garbay, Jean-Remy [Department of Breast Surgery, Institut Gustave Roussy, Villejuif (France); Bourhis, Jean [Department of Radiation Oncology, Institut Gustave Roussy, Villejuif (France); Taghian, Alphonse G. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States); Marsiglia, Hugo [Department of Radiation Oncology, Institut Gustave Roussy, Villejuif (France); Radiotherapy Unit, University of Florence, Florence (Italy)

    2011-12-01

    Purpose: Several accelerated partial breast irradiation (APBI) techniques are described in the literature, and apparently, the three-dimensional (3D)-conformal technique is being used increasingly. Nonetheless, the optimal radiation dose is not yet known. Here, we report feasibility and early toxicities of APBI delivering 40 Gy over 5 days, in a phase II trial. Methods and Materials: From October 2007 to September 2008, 25 patients with pT1N0 cancer received 3D-conformal APBI. The prescribed radiation dose was 40 Gy in 4-Gy fractions given twice daily. This technique used two minitangents and an 'en face' electron field. Toxicities were systematically assessed at 1, 2, and 6 months and then once every 6 months. Results: The planning tumor volume for evaluation (PTV{sub E}VAL) coverage was adequate: the mean dose to the PTV{sub E}VAL was 41.8 Gy (range, 41-42.4 Gy). Mean doses to the ipsilateral lung and heart were 1.6 Gy (range, 1.0-2.3 Gy) and 1.2 Gy (range, 1.0-1.6 Gy), respectively. One and two months after completion of APBI, most patients had no or mild erythema (n = 16 patients at 1 month; n = 25 patients at 2 months); none of these patients developed moist desquamation. After a median follow-up of 12 months, only 1 patient had a significant moderate field contracture (grade 2). Other reported late toxicities were grade 1. Conclusions: 3D-conformal APBI (with two minitangents and an 'en face' electron field) using a total dose of 40 Gy in 10 fractions twice daily over 5 days achieved appropriate PTV{sub E}VAL coverage and offered significant sparing of normal tissue. Early tolerance was excellent.

  20. Early Side Effects of Three-Dimensional Conformal External Beam Accelerated Partial Breast Irradiation to a Total Dose of 40 Gy in One Week (A Phase II Trial)

    International Nuclear Information System (INIS)

    Purpose: Several accelerated partial breast irradiation (APBI) techniques are described in the literature, and apparently, the three-dimensional (3D)-conformal technique is being used increasingly. Nonetheless, the optimal radiation dose is not yet known. Here, we report feasibility and early toxicities of APBI delivering 40 Gy over 5 days, in a phase II trial. Methods and Materials: From October 2007 to September 2008, 25 patients with pT1N0 cancer received 3D-conformal APBI. The prescribed radiation dose was 40 Gy in 4-Gy fractions given twice daily. This technique used two minitangents and an “en face” electron field. Toxicities were systematically assessed at 1, 2, and 6 months and then once every 6 months. Results: The planning tumor volume for evaluation (PTVEVAL) coverage was adequate: the mean dose to the PTVEVAL was 41.8 Gy (range, 41–42.4 Gy). Mean doses to the ipsilateral lung and heart were 1.6 Gy (range, 1.0–2.3 Gy) and 1.2 Gy (range, 1.0–1.6 Gy), respectively. One and two months after completion of APBI, most patients had no or mild erythema (n = 16 patients at 1 month; n = 25 patients at 2 months); none of these patients developed moist desquamation. After a median follow-up of 12 months, only 1 patient had a significant moderate field contracture (grade 2). Other reported late toxicities were grade 1. Conclusions: 3D-conformal APBI (with two minitangents and an “en face” electron field) using a total dose of 40 Gy in 10 fractions twice daily over 5 days achieved appropriate PTVEVAL coverage and offered significant sparing of normal tissue. Early tolerance was excellent.

  1. 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

  2. Beam emittance and beam disruption

    International Nuclear Information System (INIS)

    Beam disruption during the collision of intense relativistic bunches has been studied by R. Hollebeek. In the case of oppositely charged bunches, focussing effects occur causing a decrease in the effective bunch cross section, and thereby an increase of luminosity by an enhancement factor H. The term disruption derives from the fact that the beam emittance changes markedly during the collision. 1 ref., 1 fig., 1 tab

  3. 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

  4. 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...

  5. Measurement of calcium content of gallstones by computed tomography and the relationship between gallbladder function and calcification of gallstones

    Energy Technology Data Exchange (ETDEWEB)

    Yoneda, Masashi; Tamasawa, Naoki; Takebe, Kazuo (Hirosaki Univ. (Japan). School of Medicine); Makino, Isao; Sakuraba, Kiyoshi; Tamura, Toyokazu

    1990-08-01

    To evaluate the relationship between gallbladder function and calcification of gallstones, we studied gallbladder contractility by oral cholecystography, the computed tomography (CT) number of stones for 30 gallstone patients, calcium content of 13 stones operatively extirpated, and the degree of inflammatory change in 13 surgical gallbladder specimens. There was significant correlation between the calcium content and CT numbers of stones, and 1% of the calcium content of gallstone was approximately equal to 40 Hounsfield Units (HU) of the CT number. The calcium content of stones in patients with normal gallbladder contractility was extrapolated to be below 1.5%, while that with poor contractility ranged from 0% to 21%. Additionally there is a possibility that calcium content increases, related to the inflammatory change of gallbladder. Hence our results suggested that measurement of the CT number of stones is useful to evaluate the calcium content of gallstones, and that the gallbladder contractility could be one of the factors to influence calcification of stones. (author).

  6. 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

  7. 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

  8. 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.

  9. Response to an oral calcium load in nephrolithiasis patients with fluctuating parathyroid hormone and ionized calcium levels

    Directory of Open Access Journals (Sweden)

    S.A. Gomes

    2004-09-01

    Full Text Available the response to an oral calcium load test was assessed in 17 hypercalciuric nephrolithiasis patients who presented elevated parathyroid hormone (PTH irrespective of the ionized calcium (sCa2+ levels. Blood samples were collected at baseline (0 min and at 60 and 180 min after 1 g calcium load for serum PTH, total calcium, sCa2+, and 1.25(OH2D3 determinations. According to the sCa2+ level at baseline, patients were classified as normocalcemic (N = 9 or hypercalcemic (N = 8. Six healthy subjects were also evaluated as controls. Bone mineral density was reduced in 14/17 patients. In the normocalcemic group, mean PTH levels at 0, 60 and 180 min (95 ± 76, 56 ± 40, 57 ± 45 pg/ml, respectively did not differ from the hypercalcemic group (130 ± 75, 68 ± 35, 80 ± 33 pg/ml but were significantly higher compared to healthy subjects despite a similar elevation in sCa2+ after 60 and 180 min vs baseline in all 3 groups. Mean total calcium and 1.25(OH2D3 were similar in the 3 groups. Additionally, we observed that 5 of 9 normocalcemic patients presented a significantly higher concentration-time curve for serum PTH (AUC0',60',180' than the other 4 patients and the healthy subjects, suggesting a primary parathyroid dysfunction. These data suggest that the individual response to an oral calcium load test may be a valuable dynamic tool to disclose a subtle primary hyperparathyroidism in patients with high PTH and fluctuating sCa2+ levels, avoiding repeated measurements of both parameters.

  10. Response to an oral calcium load in nephrolithiasis patients with fluctuating parathyroid hormone and ionized calcium levels

    Directory of Open Access Journals (Sweden)

    Gomes S.A.

    2004-01-01

    Full Text Available the response to an oral calcium load test was assessed in 17 hypercalciuric nephrolithiasis patients who presented elevated parathyroid hormone (PTH irrespective of the ionized calcium (sCa2+ levels. Blood samples were collected at baseline (0 min and at 60 and 180 min after 1 g calcium load for serum PTH, total calcium, sCa2+, and 1.25(OH2D3 determinations. According to the sCa2+ level at baseline, patients were classified as normocalcemic (N = 9 or hypercalcemic (N = 8. Six healthy subjects were also evaluated as controls. Bone mineral density was reduced in 14/17 patients. In the normocalcemic group, mean PTH levels at 0, 60 and 180 min (95 ± 76, 56 ± 40, 57 ± 45 pg/ml, respectively did not differ from the hypercalcemic group (130 ± 75, 68 ± 35, 80 ± 33 pg/ml but were significantly higher compared to healthy subjects despite a similar elevation in sCa2+ after 60 and 180 min vs baseline in all 3 groups. Mean total calcium and 1.25(OH2D3 were similar in the 3 groups. Additionally, we observed that 5 of 9 normocalcemic patients presented a significantly higher concentration-time curve for serum PTH (AUC0',60',180' than the other 4 patients and the healthy subjects, suggesting a primary parathyroid dysfunction. These data suggest that the individual response to an oral calcium load test may be a valuable dynamic tool to disclose a subtle primary hyperparathyroidism in patients with high PTH and fluctuating sCa2+ levels, avoiding repeated measurements of both parameters.

  11. 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.)

  12. Silicon microfabricated beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A., E-mail: aliman@ppinang.uitm.edu.my; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A. [Faculty of Electrical Engineering, Universiti Teknologi MARA Malaysia, 40450, Shah Alam, Selangor (Malaysia); Ain, M. F. [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300,Nibong Tebal, Pulau Pinang (Malaysia)

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  13. A 0.1–40 GHz broadband MEMS clamped–clamped beam capacitive power sensor based on GaAs technology

    International Nuclear Information System (INIS)

    This paper presents a 0.1–40 GHz broadband MEMS capacitive power sensor based on GaAs technology. An impedance compensation method utilizing a T-matching network is proposed to expand bandwidth. A lumped parameter model is established, the reflection coefficient, the voltage on the membrane and the sensitivity of RF-power detection are derived based on the multi-reflection transmission line theory. Performances of different up-states before pull-in are analysed when the membrane is electrostatic actuated. The proposed capacitive power sensor has been fabricated using GaAs process and MEMS technology. A controllable lateral etching technique is used to improve the sensitivity of RF-power detection and a low-spring-constant membrane is obtained. Measurement results show that return and insertion losses (S11 and S21) are less than −20.31 and 0.29 dB up to 40 GHz, respectively. DC voltage measurement indicates a low pull-in voltage of 10 V. Sensitivities of different operating frequencies are measured to be 11.6 aF mW−1 at 5 GHz, 11.3 aF mW−1 at 15 GHz, 10.8 aF mW−1 at 25 GHz and 10.4 aF mW−1 at 35 GHz. Frequency dependence measurements show a decreasing trend of sensitivity with the increase of frequency. (paper)

  14. Multispot two-photon imaging of mice heart tissue detecting calcium waves

    Science.gov (United States)

    de Mauro, C.; Cecchetti, C. A.; Alfieri, D.; Borile, G.; Mongillo, M.; Pavone, F. S.

    2012-06-01

    High rate, full field image acquisition in multiphoton imaging is achievable by parallelization of the excitation and of the detection paths. Via a Diffractive Optical Elements (DOEs) which splits a pulsed laser, and a spatial resolved descanned detection path, a new approach to microscopy has been developed. By exploiting the three operating mode, single beam, 16 beamlets or 64 beamlets, the best experimental conditions can be found by adapting the power per beamlet. This Multiphoton Multispot system (MCube) has been characterized in thick tissue samples, and subsequently used for the first time for Ca2+ imaging of acute heart slices. A test sample with fixed mice heart slices with embedded sub-resolution fluorescent beads has been used to test the capability of optical axial resolution up to ~200 microns in depth. Radial and axial resolutions of 0.6 microns and 3 microns have been respectively obtained with a 40X water immersion objective, getting close to the theoretical limit. Then images of heart slices cardiomyocites, loaded with Fluo4-AM have been acquired. The formation of Ca2+ waves during electrostimulated beating has been observed, and the possibility of easily acquire full frame images at 15 Hz (16 beamlets) has been demonstrated, towards the in vivo study of time resolved cellular dynamics and arrhythmia trigger mechanisms in particular. A very high speed two-photon Random Access system for in vivo electrophysiological studies, towards the correlation of voltage and calcium signals in arrhythmia phenomena, is now under developing at Light4tech.

  15. Neutron production by neutral beam sources

    Energy Technology Data Exchange (ETDEWEB)

    Berkner, K.H.; Massoletti, D.J.; McCaslin, J.B.; Pyle, R.V.; Ruby, L.

    1979-11-01

    Neutron yields, from interactions of multiampere 40- to 120-keV deuterium beams with deuterium atoms implanted in copper targets, have been measured in order to provide input data for shielding of neutral-deuterium beam facilities for magnetic fusion experiments.

  16. Clinical usefulness of multidetector-row CT to evaluate coronary artery calcium score in type 2 diabetes

    International Nuclear Information System (INIS)

    According to recent studies, multidetector-row CT (MDCT) with a retrospective electrocardiogram (ECG)-gating reconstruction algorithm shows a high correlation with coronary artery calcium score determined using electron-beam CT. Diabetes leads to many macrovascular complications, including coronary artery disease. The aim of this study was to evaluate risk factors for cardiac macroangiopathy in type 2 diabetes using MDCT. An observational cross-sectional study was performed in 90 patients with diabetes mellitus. Coronary calcium data was acquired by MDCT (SOMATOM Volume Zoom, Siemens AG, Medical Solutions, Germany). Physical examinations, laboratory data, glycemic control, and control of other risk factors were analyzed. The coronary artery calcium score increased with age. Multivariant analysis revealed that the coronary calcium score was closely correlated with electrocardiogram evaluation and control of hypertension. Coronary artery calcium score as determined by MDCT can be used as a screening radiological examination for cardiac macroangiopathy in diabetes patients with electrocardiogram abnormality and hypertension. (author)

  17. Changes in intracellular calcium in brain cells of aged rats

    Institute of Scientific and Technical Information of China (English)

    Yu Li; Yunpeng Cao

    2008-01-01

    BACKGROUND: Studies have shown that voltage-dependent calcium influx, and enhancement of certain calcium-dependent processes in neurons, is related to aging. OBJECTIVE: To observe changes in intracellular calcium ([Ca2+]i) in neurons of aged rats, and to compare with young rats. DESIGN, TIME AND SETTING: A randomized control experiment of neurophysiology was performed at the Central Laboratory of School of Pharmaceutical Science, China Medical University from June to August 2004. MATERIALS: Ten male, healthy, Wistar rats, 19 months old, were selected for the aged group. Ten male, 3-month-old, Wistar rats were selected for the young control group. Fura-2/AM was provided by the Institute of Pharmaceutical Research of Chinese Academy of Medical Sciences, and the F-2000 fluorospectrophotometer was a product of Hitachi, Japan. METHODS: Fluorescence Fura-2 spectrophotometer was used to measure [Ca2+]i in acutely dissociated brain cells of aged and young rats. The concentration of extracellular potassium was controlled by adding different volumes of chloridated potassium solution of high concentration. MAIN OUTCOME MEASURES: [Ca2+]i in neurons of young and aged rats in the presence of 1 mmol/L extracellular calcium concentration and 0 mmol/L (resting state), 5, 10, 20, and 40 mmol/L extracellular potassium. Absolute increase of [Ca2+]i in neurons of young and aged rats when extraceUular potassium was 5,10,20, 40 mmol/L. RESULTS: In the presence of 1 mmol/L extracellular Ca2+ and 0 mmol/L (resting state), 5, 10, 20, and 40 mmol/L extracellular potassium, [Ca2+]i in the neurons of aged rats was significantly less than that in young rats (P 0.05). CONCLUSION: The overload of [Ca2+]i in neurons of aged rats is greater than that of young rats under the same circumstances.

  18. Physical vapor deposition and patterning of calcium fluoride films

    International Nuclear Information System (INIS)

    Physical vapor deposition of calcium fluoride (CaF2) thin films was performed via electron beam evaporation, resistive/thermal evaporation, and nonreactive radio frequency sputtering. Patterning of the resultant ''usable'' thin films was then also attempted in several ways, including by shadow mask deposition, liftoff, and direct chemical etching. Resistive evaporation produced the most stable films, having polycrystalline morphology with a moderately strong preference to the 331 orientation. The cleanest patterning results were obtained via a polymer/metal liftoff. The results and implications of each of the various deposition and patterning techniques are discussed.

  19. Complex formation ions calcium with macromolecules pectin

    International Nuclear Information System (INIS)

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

  20. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Devkanya Dutta

    2000-12-01

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

  1. Dairy Dilemma: Are You Getting Enough Calcium?

    Science.gov (United States)

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

  2. Calcium, vitamin D, and your bones

    Science.gov (United States)

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

  3. Theoretical evaluation of induced radioactivity in food products by electron — or X-ray beam sterilization

    Science.gov (United States)

    Leboutet, H.; Aucouturier, J.

    We evaluate first the energy density for electrons or X-ray beams necessary to produce a reference level of 1 kilogray at the maximum of dose, as a function of energy, for electrons and bremsstrahlung photons ( BX rays), based on experimental data obtained on radio-therapy beams, from 4 to 32 MeV, and irradiation beams from production plant CARIC. Then from the production of neutrons on the tungsten target and from (γ n) reactions on the deuterium content of the irradiated food, the slowing down and capture of these neutrons is estimated. Radioisotopes can be produced by (γ n) reactions on iodine, and to a lesser extent on tin, lead, barium, etc., but the major contribution is neutron activation, where the more critical elements are sodium, chlorine, potassium, magnesium, phosphorus, calcium. Induced activity is compared to natural activity coming from potassium 40, carbon 14 and radium, contained in all foods. We conclude that for electrons up to 1 Mrad the induced activity remains of the order of a few percent of natural activity, for energies below 10-11 MeV. Bremsstrahlung X-ray irradiations can give comparable levels as soon as the energy of the generating electron beam is above 3 MeV. The induced activity decays within a few days. There is only a small increase of induced activity as the energy changes from 5 to 10 MeV, for the same total applied dose.

  4. Gelsolin mediates calcium-dependent disassembly of Listeria actin tails

    Science.gov (United States)

    Larson, Laura; Arnaudeau, Serge; Gibson, Bruce; Li, Wei; Krause, Ryoko; Hao, Binghua; Bamburg, James R.; Lew, Daniel P.; Demaurex, Nicolas; Southwick, Frederick

    2005-01-01

    The role of intracellular Ca2+ in the regulation of actin filament assembly and disassembly has not been clearly defined. We show that reduction of intracellular free Ca2+ concentration ([Ca2+]i) to <40 nM in Listeria monocytogenes-infected, EGFP–actin-transfected Madin–Darby canine kidney cells results in a 3-fold lengthening of actin filament tails. This increase in tail length is the consequence of marked slowing of the actin filament disassembly rate, without a significant change in assembly rate. The Ca2+-sensitive actin-severing protein gelsolin concentrates in the Listeria rocket tails at normal resting [Ca2+]i and disassociates from the tails when [Ca2+]i is lowered. Reduction in [Ca2+]i also blocks the severing activity of gelsolin, but not actin-depolymerizing factor (ADF)/cofilin microinjected into Listeria-infected cells. In Xenopus extracts, Listeria tail lengths are also calcium-sensitive, markedly shortening on addition of calcium. Immunodepletion of gelsolin, but not Xenopus ADF/cofilin, eliminates calcium-sensitive actin-filament shortening. Listeria tail length is also calcium-insensitive in gelsolin-null mouse embryo fibroblasts. We conclude that gelsolin is the primary Ca2+-sensitive actin filament recycling protein in the cell and is capable of enhancing Listeria actin tail disassembly at normal resting [Ca2+]i (145 nM). These experiments illustrate the unique and complementary functions of gelsolin and ADF/cofilin in the recycling of actin filaments. PMID:15671163

  5. Masses of exotic calcium isotopes pin down nuclear forces

    CERN Document Server

    Wienholtz, F; Blaum, K; Borgmann, Ch; Breitenfeldt, M; Cakirli, R B; George, S; Herfurth, F; Holt, J D; Kowalska, M; Kreim, S; Lunney, D; Manea, V; Menéndez, J; Neidherr, D; Rosenbusch, M; Schweikhard, L; Schwenk, A; Simonis, J; Stanja, J; Wolf, R N; Zuber, K

    2013-01-01

    The properties of exotic nuclei on the verge of existence play a fundamental part in our understanding of nuclear interactions. Exceedingly neutron-rich nuclei become sensitive to new aspects of nuclear forces. Calcium, with its doubly magic isotopes $^{40}$Ca and $^{48}$Ca, is an ideal test for nuclear shell evolution, from the valley of stability to the limits of existence. With a closed proton shell, the calcium isotopes mark the frontier for calculations with three-nucleon forces from chiral effective field theory. Whereas predictions for the masses of $^{51}$Ca and $^{52}$Ca have been validated by direct measurements$^4$, it is an open question as to how nuclear masses evolve for heavier calcium isotopes. Here we report the mass determination of the exotic calcium isotopes $^{53}$Ca and $^{54}$Ca, using the multi-reflection time-of-flight mass spectrometer of ISOLTRAP at CERN. The measured masses unambiguously establish a prominent shell closure at neutron number N = 32, in excellent agreement with our t...

  6. Quantification of Calcium Isotope Fractionation in Ectomycorrhizal Trees

    Science.gov (United States)

    Hoff, C. J.; Bryce, J. G.; Hobbie, E. A.; Colpaert, J. V.; Bullen, T. D.

    2005-12-01

    Calcium plays a significant role in many forest ecosystem processes and is required for plant growth. Within plants, calcium is a critical component of cell walls and membranes, signaling processes, and charge balances (1). Current efforts to quantify Ca cycling in ecosystems rely on large-scale ecosystem manipulations (e.g., 2) or mass balances (e.g., 3) and indirect chemical proxies, Ca/Sr or Sr isotopic systems (e.g., 4). The measurement of Ca isotopes may provide more direct information about the calcium sources and fluxes within and between the geological (mineral and soil) and biological (fungi and plants) components of terrestrial ecosystems. To examine calcium isotopic variability systematically, we measured the fractionation between roots and needles in cultured Scots pine ( Pinus sylvestris) seedlings. Our samples include roots and needles from trees grown at low or high nutrient supply rates (3% or 5% per day). Because mycorrhizal fungi are intimately involved in plant nutrient supply, we also tested whether mycorrhizal colonization by Suillus bovinus affected calcium isotopic fractionation. Initial results demonstrate that at a low nutrient supply rate there is a small but measurable fractionation (averaging 0.58 ‰) between the roots and needles of individual trees; the needles are enriched in 40Ca compared to the roots. The root-needle fractionation is unaffected by mycorrhizal colonization. Ongoing analyses will address both the consistency of the root-needle fractionation and the impacts of nutrient supply rate on fractionation. Preliminary results suggest that higher nutrient supply rates lead to decreased root-needle fractionation. Analyses underway will also address whether different fungal species ( Thelephora terrestris) affect the documented root-needle fractionation. Isotope signatures of calcium source materials will complete our sample suite and will be used to assess fractionation during uptake. Ultimately, the results of this study will

  7. Calcium channel blockers and Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Yi Tan; Yulin Deng; Hong Qing

    2012-01-01

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

  8. Calcium channel blockers and Alzheimer's disease★

    OpenAIRE

    Tan, Yi; Deng, Yulin; Qing, Hong

    2012-01-01

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

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

    Science.gov (United States)

    Liang, Willmann

    2008-01-01

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

  10. Electrophysical properties of calcium orthovanadate

    International Nuclear Information System (INIS)

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

  11. LHC beam loss pattern recognition

    CERN Document Server

    Marsili, A; Puzo, P

    2011-01-01

    One of the systems protecting CERN’s Large Hadron Collider (LHC) is the Beam Loss Monitoring system (BLM). More than 3600 monitors are installed around the ring. The beam losses are permanently integrated over 12 different time intervals (from 40 microseconds to 84 seconds). When any loss exceeds the thresholds defined for the integration window, the beam is removed from the machine. Understanding the origin of a beam loss is crucial for machine operation, as it can help to avoid a repetition of the same scenario. The signals read from given monitors can be considered as entries of a vector. This article presents how a loss map of unknown cause can be decomposed using vector based analysis derived from well-known loss scenarios. The algorithms achieving this decomposition are described, as well as the accuracy of the results.

  12. 21 CFR 582.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  13. 21 CFR 182.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  14. 21 CFR 582.5217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  15. 21 CFR 582.1191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

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

  16. 21 CFR 582.5191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

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

  17. 21 CFR 73.1070 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

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

  18. 21 CFR 582.1205 - Calcium hydroxide.

    Science.gov (United States)

    2010-04-01

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

  19. 21 CFR 182.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

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

  20. 21 CFR 582.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

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

  1. Calcium dynamics in vascular smooth muscle

    OpenAIRE

    Amberg, Gregory C.; Navedo, Manuel F.

    2013-01-01

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

  2. 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

  3. Dosimetric properties of germanium doped calcium borate glass subjected to 6 MV and 10 MV X-ray irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Tengku Kamarul Bahri, T.N.H., E-mail: tnhidayah2@gmail.com [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru (Malaysia); Wagiran, H.; Hussin, R.; Saeed, M.A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru (Malaysia); Hossain, I. [Department of Physics, College of Science and Arts, King Abdul Aziz University, 21911 Rabigh (Saudi Arabia); Ali, H. [Department of Radiotherapy and Oncology, Hospital Sultan Ismail, 81100 Johor Bahru (Malaysia)

    2014-10-01

    Highlights: •The TL properties of 29.9CaO–70B{sub 2}O{sub 3}: 0.1GeO{sub 2} glass has been investigated. •We exposed glass samples to 6 MV and 10 MV in a dose range of 0.5–4.0 Gy. •This glass has a potential material to be used for application in radiotherapy. -- Abstract: Germanium doped calcium borate glasses are investigated in term of thermoluminescence properties to seek their possibility to use as glass radiation dosimeter. The samples were exposed to 6 MV, and 10 MV photon beams in a dose range of 0.5–4.0 Gy. There is a single and broad thermoluminescence glow curve that exhibits its maximum intensity at about 300 °C. Linear dose response behavior has been found in this dose range for the both photon energies. Effective atomic number, TL sensitivity, and reproducibility have also been studied. It is found that the sensitivity of germanium doped sample at 6 MV is only 1.28% and it is superior to the sensitivity at 10 MV. The reproducibility of germanium doped sample is good with a percentage of relative error less than 10%. The results indicate that this glass has a potential to be used as a radiation dosimetry, especially for application in radiotherapy.

  4. Calcium and available phosphorus levels for laying hens in second production cycle

    OpenAIRE

    K Pelicia; EA Garcia; ABG Faitarone; de Silva AP; DA Berto; AB Molino; F Vercese

    2009-01-01

    This experiment studied the effect of four calcium (3.0, 3.5, 4.0, and 4.5%) and four available phosphorus levels (0.25, 0.30, 0.35, and 0.40%) in the diet of semi-heavy commercial layers after molting. Hisex Brown® layers between 90 and 108 weeks of age were distributed in a completely randomized experimental design with a 4x4 factorial arrangement with 16 treatments of five replicates of eight birds each. mortality, egg production, feed intake, egg mass, average egg weight, calcium and phos...

  5. Energy loss and charge state distribution of calcium ions in dense moderately coupled carbon plasma

    International Nuclear Information System (INIS)

    loss depends more sensitively on the plasma ionization degree than on the projectile charge state. Finally the energy loss and the charge state distribution of a calcium ion beam have been experimentally investigated in the considered hohlraum plasma. The energy loss has been measured with a time of flight method and the charge state distribution with a magnet charge state spectrometer. The measurements show an increase of the energy loss of more than 80% from (22±3) keV/(μg/cm2) in solid carbon to (40±4) keV/(μg/cm2) in carbon plasma. The experimental results lie 10 to 15% above the predictions of common stopping power theories. The measured charge state distribution of the ion beam after interaction with the plasma shows no significant difference with the distribution after interaction with a cold carbon foil, as expected from the simulations. The measured mean charge state for cold carbon is 16.8±1.2 and the value after the interaction with the plasma is 16.9±1.4.

  6. GABA(A) Increases Calcium in Subventricular Zone Astrocyte-Like Cells Through L- and T-Type Voltage-Gated Calcium Channels

    DEFF Research Database (Denmark)

    Young, Stephanie Z; Platel, Jean-Claude; Nielsen, Jakob V;

    2010-01-01

    induced Ca(2+) increases in 40-50% of SVZ astrocytes. GABA(A)-induced Ca(2+) increases were prevented with nifedipine and mibefradil, blockers of L- and T-type voltage-gated calcium channels (VGCC). The L-type Ca(2+) channel activator BayK 8644 increased the percentage of GABA(A)-responding astrocyte...

  7. Relativistic electron beams above thunderclouds

    Directory of Open Access Journals (Sweden)

    M. Füllekrug

    2011-08-01

    Full Text Available Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency ∼40–400 kHz which they radiate. The electron beams occur ∼2–9 ms after positive cloud-to-ground lightning discharges at heights between ∼22–72 km above thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of ∼7 MeV to transport a total charge of ∼−10 mC upwards. The impulsive current ∼3 × 10−3 Am−2 associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.

  8. Application of diamond based beam loss monitors

    International Nuclear Information System (INIS)

    The LHC has an operational stored energy of 130MJ per beam. Only a small percentage of beam losses in the LHC equipment can damage material or lead to magnet quenches. Therefore, it is important to monitor different types of beam losses, e.g. scattering on residual gas particles, UFOs, collisions and injection losses. A detailed understanding of beam loss mechanisms is necessary to reduce them and ensure save operation. Two different beam loss monitors are installed in the LHC tunnel: ionization chambers and diamond sensors. Ionization chambers trigger a beam dump if beam losses exceed a certain threshold. They have a time resolution of 40um (half LHC turn) which is not sufficient to resolve bunch-by-bunch beam losses. Diamond sensors have a nanosecond time resolution and can therefore detect bunch-by-bunch beam losses. This time resolution allows an analysis of various types of beam losses and an understanding of the mechanisms. For the first time beam loss intensities were measured bunch-by-bunch caused by different origins of losses. Beam loss measurements using diamond sensors will be presented. The results are compared to simulations and good qualitative agreement was found. The potential of diamond sensors for LHC and experiment applications are discussed.

  9. Application of diamond based beam loss monitors

    Energy Technology Data Exchange (ETDEWEB)

    Hempel, Maria [Brandenburgische Technische Univ. Cottbus (Germany); DESY, Zeuthen (Germany); CERN, Geneva (Switzerland); Baer, Tobias [CERN, Geneva (Switzerland); Hamburg Univ. (Germany); Castro Carballo, Elena Maria [DESY, Zeuthen (Germany); Lohmann, Wolfgang [Brandenburgische Technische Univ. Cottbus (Germany); DESY, Zeuthen (Germany); Schmidt, Ruediger [CERN, Geneva (Switzerland)

    2013-07-01

    The LHC has an operational stored energy of 130MJ per beam. Only a small percentage of beam losses in the LHC equipment can damage material or lead to magnet quenches. Therefore, it is important to monitor different types of beam losses, e.g. scattering on residual gas particles, UFOs, collisions and injection losses. A detailed understanding of beam loss mechanisms is necessary to reduce them and ensure save operation. Two different beam loss monitors are installed in the LHC tunnel: ionization chambers and diamond sensors. Ionization chambers trigger a beam dump if beam losses exceed a certain threshold. They have a time resolution of 40um (half LHC turn) which is not sufficient to resolve bunch-by-bunch beam losses. Diamond sensors have a nanosecond time resolution and can therefore detect bunch-by-bunch beam losses. This time resolution allows an analysis of various types of beam losses and an understanding of the mechanisms. For the first time beam loss intensities were measured bunch-by-bunch caused by different origins of losses. Beam loss measurements using diamond sensors will be presented. The results are compared to simulations and good qualitative agreement was found. The potential of diamond sensors for LHC and experiment applications are discussed.

  10. Synthesis of hollow spherical calcium phosphate nanoparticles using polymeric nanotemplates

    International Nuclear Information System (INIS)

    Poly(methylmethacrylate)-block-poly(methacrylic acid) (PMMA-b-PMAA) copolymer was synthesized by an atom transfer radical polymerization (ATRP) technique. The block copolymer was employed as a template for the controlled precipitation of calcium phosphate from aqueous solution at different pH values. A Ca2+ ion selective electrode was used to study the interactions between Ca2+ ions and the polymer, which indicated a possible weak interaction between Ca2+ and un-ionized MAA segments at pH∼4.0 in addition to electrostatic interaction between Ca2+ and ionized MAA segments at higher pH. An interesting structure representing that of a superstructure consisting of hybrid nano-filaments was observed by the transmission electron microscope at pH∼4.0. The filaments originated from a core of similar size to primary polymer aggregates, suggesting that cooperative interactions at a local level between dissolving calcium phosphate clusters and disassembling polymer segments are responsible for the secondary growth process. A hollow spherical morphology was obtained at pH∼7.0 and 9.0. Such calcium phosphate/polymer monohybrids with complex morphologies are interesting and might be useful as novel drug delivery carriers, ceramics precursors, reinforcing fillers or biomedical implants

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

    OpenAIRE

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

    2010-01-01

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

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

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

    OpenAIRE

    Zenei Taira, Zenei

    2013-01-01

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

  14. Calcium Carbonate versus Sevelamer Hydrochloride as Phosphate Binders after Long-Term Disease Progression in 5/6 Nephrectomized Rats

    Directory of Open Access Journals (Sweden)

    Suvi Törmänen

    2014-01-01

    Full Text Available Our aim was to compare the effects of calcium carbonate and sevelamer-HCl treatments on calcium-phosphate metabolism and renal function in 5/6 nephrectomized (NX rats so that long-term disease progression preceded the treatment. After 15-week progression, calcium carbonate (3.0%, sevelamer-HCl (3.0%, or control diets (0.3% calcium were given for 9 weeks. Subtotal nephrectomy reduced creatinine clearance (−40%, plasma calcidiol (−25%, and calcitriol (−70% and increased phosphate (+37%, parathyroid hormone (PTH (11-fold, and fibroblast growth factor-23 (FGF-23 (4-fold. In NX rats, calcium carbonate diet increased plasma (+20% and urinary calcium (6-fold, reduced plasma phosphate (−50% and calcidiol (−30%, decreased creatinine clearance (−35% and FGF 23 (−85%, and suppressed PTH without influencing blood pH. In NX rats, sevelamer-HCl increased urinary calcium (4-fold and decreased creatinine clearance (−45%, PTH (−75%, blood pH (by 0.20 units, plasma calcidiol (−40%, and calcitriol (−65%. Plasma phosphate and FGF-23 were unchanged. In conclusion, when initiated after long-term progression of experimental renal insufficiency, calcium carbonate diet reduced plasma phosphate and FGF-23 while sevelamer-HCl did not. The former induced hypercalcemia, the latter induced acidosis, while both treatments reduced vitamin D metabolites and deteriorated renal function. Thus, delayed initiation influences the effects of these phosphate binders in remnant kidney rats.

  15. Calcium signals and calcium channels in osteoblastic cells

    Science.gov (United States)

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

    1998-01-01

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

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

    Science.gov (United States)

    Talukdar, Keka; Shantappa, Anil

    2016-05-01

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

  17. Spectroscopy and Stark-effect of Rydberg states in Ca and Sr in an atomic beam experiment

    International Nuclear Information System (INIS)

    Rydberg states of Calcium and Strontium were excited by laser radiation in an atomic beam experiment. Such spectroscopy of the Rydberg series could be done in both elements and also the Stark effect was examined in Strontium. (BEF)

  18. Misrepair of DNA double-strand breaks after exposure to heavy-ion beams causes a peak in the LET-RBE relationship with respect to cell killing in DT40 cells

    International Nuclear Information System (INIS)

    To determine the radiobiological mechanisms underlying relative biological effectiveness (RBE) and the repair efficiencies of DNA double-strand breaks (DSBs) as a function of linear energy transfer (LET), we exposed cells of the chicken B-lymphocyte cell line DT40 and its DSB repair pathway-deficient derivatives to heavy-ion beams produced at the Heavy-Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), Chiba, Japan. The relationship between LET and cell lethality was investigated in the DNA DSB repair gene knockouts Ku70-/-, Rad54-/-, and Ku70-/-Rad54-/-, and in the wild-type cells. We found that cell-cycle stage and activity of the DNA DSB repair pathways influence LET-mediated biological effects. An expected LET-RBE relationship was observed in the cells capable of DNA repair, but no peak was found in the RBE with respect to cell survival in the Ku70-/-Rad54-/- cells or in Ku70-/- cells in the G1 and early S cell-cycle phases (when no sister chromatids were present and homologous recombination could not occur). These findings suggest that the peak in RBE is caused by deficient repair of the DNA DSBs. (author)

  19. Contribution to the study of calcium metabolism in the deficiency of testosterone

    International Nuclear Information System (INIS)

    Kinetic parameters of calcium mobilization in rats were determined to estimate the role of testosterone in the metabolism of this ion. Calcium multicompartimental theory was combined to and used in measurements of metabolic balance (for 45CaCl2 or 40CaCl2). Three groups of 60 day old rats were used: G I-control; G II-castrated; G III-castrated and treated with testosterone propionate. Data were obtained from measurements of Ca++ in samples of plasma, feces and urine. Balance studies suggest that calcium level in blood plasma remained constant in all groups, the increase of bone reabsorption in groups II and III being counterbalanced by the elevation of the urinary excrection. This result implies the equilibrium occurring at renal level. Intestinal calcium absorption remained the same in the three groups of animals, indicating that testosterone has no consistent effect at intestinal level. The increase of total calcium in feces of groups II and III arises from a great endogenous secretion. A significant negative balance of calcium was also observed in these groups. This fact permits the conclusion that in the absence of testosterone the organism doesn't retain calcium efficiently. (M.A.)

  20. Cytoplasmic calcium levels in protoplasts from the cap and elongation zone of maize roots

    Science.gov (United States)

    Kiss, H. G.; Evans, M. L.; Johnson, J. D.

    1991-01-01

    Calcium has been implicated as a key component in the signal transduction process of root gravitropism. We measured cytoplasmic free calcium in protoplasts isolated from the elongation zone and cap of primary roots of light-grown, vertically oriented seedlings of Zea mays L. Protoplasts were loaded with the penta-potassium salts of fura-2 and indo-1 by incubation in acidic solutions of these calcium indicators. Loading increased with decreasing pH but the pH dependence was stronger for indo-1 than for fura-2. In the case of fura-2, loading was enhanced only at the lowest pH (4.5) tested. Dyes loaded in this manner were distributed predominantly in the cytoplasm as indicated by fluorescence patterns. As an alternative method of loading, protoplasts were incubated with the acetoxymethylesters of fura-2 and indo-1. Protoplasts loaded by this method exhibited fluorescence both in the cytoplasm and in association with various organelles. Cytoplasmic calcium levels measured using spectrofluorometry, were found to be 160 +/- 40 nM and 257 +/- 27 nM, respectively, in populations of protoplasts from the root cap and elongation zone. Cytoplasmic free calcium did not increase upon addition of calcium to the incubation medium, indicating that the passive permeability to calcium was low.

  1. Beam transport

    International Nuclear Information System (INIS)

    The beam diagnostic components for both the transfer and the high-energy beamlines perform well except for some of the scanners whose noise pick-up has become a problem, especially at low beam intensities. This noise pick-up is primarily due to deterioration of the bearings in the scanner. At some locations in the high-energy beamlines, scanners were replaced by harps as the scanners proved to be practically useless for the low-intensity beams required in the experimental areas. The slits in the low-energy beamline, which are not water-cooled, have to be repaired at regular intervals because of vacuum leaks. Overheating causes the ceramic feedthroughs to deteriorate resulting in the vacuum leaks. Water-cooled slits have been ordered to replace the existing slits which will later be used in the beamlines associated with the second injector cyclotron SPC2. The current-measurement system will be slightly modified and should then be much more reliable. 3 figs

  2. Substitution of calcium by strontium within selected calcium phosphates

    Science.gov (United States)

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

    1993-06-01

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

  3. Calcium biofortification and bioaccessibility in soilless "baby leaf" vegetable production.

    Science.gov (United States)

    D'Imperio, Massimiliano; Renna, Massimiliano; Cardinali, Angela; Buttaro, Donato; Serio, Francesco; Santamaria, Pietro

    2016-12-15

    Calcium is an essential nutrient for human health, because it is a structural component and takes part in a variety of biological processes. The aim of this study was to increase Ca content of baby leaf vegetables (BLV: basil, mizuna, tatsoi and endive), as fresh-cut products. For the production of biofortified BLV, a floating system with two level of Ca (100 and 200mgL(-1)) in the nutrient solution was used. In addition, the assessment of bioaccessibility of Ca, by in vitro digestion process, was performed. In all vegetables, the Ca biofortification (200mgL(-1)) caused a significant Ca enrichment (9.5% on average) without affecting vegetables growth, oxalate contents and marketable quality. Calcium bioaccessibility ranged from 25% (basil) to 40% (endive) but the biofortified vegetables showed more bioaccessible Ca. These results underline the possibility to obtain Ca biofortified BLV by using agronomic approaches. PMID:27451166

  4. External Beam Therapy (EBT)

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z External Beam Therapy (EBT) External beam therapy (EBT) is a ... follow-up should I expect? What is external beam therapy and how is it used? External beam ...

  5. USING CALCIUM CARBONATE WHISKERS AS PAPERMAKING FILLER

    Directory of Open Access Journals (Sweden)

    Xiaoyu Chen

    2011-05-01

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

  6. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    Directory of Open Access Journals (Sweden)

    Choksi Krishna

    2011-03-01

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

  7. Electron beam ion source and electron beam ion trap (invited).

    Science.gov (United States)

    Becker, Reinard; Kester, Oliver

    2010-02-01

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not "sorcery" but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future. PMID:20192368

  8. Neutron stimulated emission computed tomography applied to the assessment of calcium deposition due to the presence of microcalcifications associated with breast cancer; Tomografia computadorizada de emissao estimulada por neutrons aplicada para avaliar a deposicao de calcio devido a presenca de microcalcificacoes associadas ao cancer de mama

    Energy Technology Data Exchange (ETDEWEB)

    Viana, Rodrigo S.S.; Yoriyaz, Helio [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, (SP) (Brazil)

    2011-07-01

    In this paper we presented an application of the Neutron Stimulated Emission Computed Tomography (NSECT), which uses a thin beam of fast neutrons to stimulate stable nuclei in a sample, emitting characteristic gamma radiation. The photon energy is unique and it is used to identify the emitting nuclei. This technique was applied for evaluating the calcium isotopic composition changing due to the development of breast microcalcifications. A particular situation was simulated in which clustered microcalcifications were modeled with diameters less than 1.40 mm. In this case, neutron beam breast spectroscopy was successful in detecting the counting changes in the photon emission spectra for energies, which are characteristics of 4{sup 0C}a isotope in a low deposited dose rate. (author)

  9. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    International Nuclear Information System (INIS)

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H3PO4/P2O5/Et3PO4 followed by acid–base reaction with Ca(OAc)2 to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for 1H, and 31P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO4 or CaCl2 were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min

  10. [Calcium pyrophosphate dihydrate deposition disease].

    Science.gov (United States)

    Koitschev, C; Kaiserling, E; Koitschev, A

    2003-08-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  12. Self-diffusion of calcium ions in soda-lime and slag glasses

    International Nuclear Information System (INIS)

    The self-diffusion coefficients of calcium ions in 16Na2O.12CaO.72SiO2(wt%) glass and 40CaO.20Al2O3.40SiO2(wt%) slag glass at temperatures near and below transition point have been measured employing radio-isotope 45Ca. The concentration gradient of radio-activity in surface layer of glass samples after diffusion annealing was determined by counting the residual activity with a GM-tube counter on the surface by progressively chemical etching away the material in steps of about 1 micron meter. It was found that the self-diffusion coefficients of calcium ions in both glasses below the transition point were of the order of 10-14 -- 10-16 cm2/s, suggesting that the mobility of calcium ions was extremely small in the solid glasses. The activation energy for diffusion of calcium ions in solid glasses was about 60 kcal/mol, which seemed to be reasonable in comparison with the electrostatic binding energy between cation and oxygen ion. The self-diffusion coefficients of calcium ions in the slag glass agrees closely with those of oxygen ions below the transition point, while the self-diffusion coefficients of calcium ions in the soda-lime glass are greater by one order of magnitude than those of oxygen ions in the same glass. The difference of diffusion behavior of calcium ions in the slag and the soda-lime glasses may be attributed to action of alkali ions on the mobility of calcium ions. (auth.)

  13. Test Beam Coordination: 2003 ATLAS Combined Test Beam

    CERN Multimedia

    Di Girolamo, B.

    The 2003 Test Beam Period The 2003 Test Beam period has been very fruitful for ATLAS. In spite of several days lost because of the accelerator problems, ATLAS has been able to achieve many results: FCAL has completed the calibration program in H6 Tilecal has completed the calibration program in H8 Pixel has performed extensive studies with normal and high intensity beams (up to 1.4*108 hadrons/spill) SCT has completed a variety of studies with quite a high number of modules operated concurrently TRT has performed several studies at high, low and very low energy (first use of the new H8 beam in the range 1 to 9 GeV) Muons (MDT,RPC and TGC) have been operating a large setup for about 5 months. The almost final MDT ROD (MROD) has been integrated in the readout and the final trigger electronics for TGC and RPC has been tested and certified with normal beam and during dedicated 40 MHz beam periods. The TDAQ has exploited a new generation prototype successfully and the new Event Filter infrastructure f...

  14. Influence of calcium oxalate crystal accumulation on the calcium content of seeds from Medicago truncatula.

    Science.gov (United States)

    Nakata, Paul A

    2012-04-01

    Crystals of calcium oxalate often form in cells adjacent to the vascular bundles in the tissues along the xylem stream. This spatial crystal pattern suggests a role for calcium oxalate formation in regulating calcium transport and partitioning to edible organs such as seeds. To investigate this potential role, microscopic and biochemical comparisons were conducted on the different tissues of Medicago truncatula wild-type and the calcium oxalate defective (cod) 5 which lacks the ability to accumulate prismatic crystals in the cells adjacent to the vascular bundles. Calcium measurements showed that cod5 seeds had more calcium and cod5 pods contained less calcium than the corresponding wild-type tissues. Roots, stems, and leaves from cod5 and wild-type had similar calcium content. Although cod5 was devoid of prismatic crystals, cod5 pods were observed to form druse crystals of calcium oxalate not found in wild-type pods. Taken together these findings suggest a functional role for calcium oxalate formation in regulating calcium transport to the seeds. Regulating calcium uptake at the roots also appeared to be another point of control in determining seed calcium content. Overall, regulating the long distance transport and partitioning of calcium to the seeds appears to be a complex process with multiple points of control. PMID:22325887

  15. Serum calcium in pulmonary tuberculosis

    OpenAIRE

    Subhash C. Sharma

    1981-01-01

    Serum calcium was studied serially in 94 patients with active pulmonary tuberculosis. An equal number of age- and sex-matched patients with chronic obstructive pulmonary disease were controls. Seventy patients in the study group were normocalcaemic and 10 were hypercalcaemic. These 10 were on a higher supplement of vitamin D than the 70 normocalcaemic patients. There was a positive correlation between the daily vitamin intake and the degree and duration of hypercalcaemia. None of the controls...

  16. Drying dichloromethane over calcium hydride

    OpenAIRE

    sprotocols

    2015-01-01

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

  17. CCN3 and calcium signaling

    Directory of Open Access Journals (Sweden)

    Li Chang Long

    2003-08-01

    Full Text Available Abstract The CCN family of genes consists presently of six members in human (CCN1-6 also known as Cyr61 (Cystein rich 61, CTGF (Connective Tissue Growth Factor, NOV (Nephroblastoma Overexpressed gene, WISP-1, 2 and 3 (Wnt-1 Induced Secreted Proteins. Results obtained over the past decade have indicated that CCN proteins are matricellular proteins, which are involved in the regulation of various cellular functions, such as proliferation, differentiation, survival, adhesion and migration. The CCN proteins have recently emerged as regulatory factors involved in both internal and external cell signaling. CCN3 was reported to physically interact with fibulin-1C, integrins, Notch and S100A4. Considering that, the conformation and biological activity of these proteins are dependent upon calcium binding, we hypothesized that CCN3 might be involved in signaling pathways mediated by calcium ions. In this article, we review the data showing that CCN3 regulates the levels of intracellular calcium and discuss potential models that may account for the biological effects of CCN3.

  18. Characteristics of the interaction of calcium with casein submicelles as determined by analytical affinity chromatography

    International Nuclear Information System (INIS)

    Interaction of calcium with casein submicelles was investigated in CaCl2 and calcium phosphate buffers and with synthetic milk salt solutions using the technique of analytical affinity chromatography. Micelles that had been prepared by size exclusion chromatography with glycerolpropyl controlled-pore glass from fresh raw skim milk that had never been cooled, were dialyzed at room temperature against calcium-free imidazole buffer, pH 6.7. Resulting submicelles were covalently immobilized on succinamidopropyl controlled-pore glass (300-nm pore size). Using 45Ca to monitor the elution retardation, the affinity of free Ca2+ and calcium salt species was determined at temperatures of 20 to 40 degrees C and pH 6.0 to 7.5. Increasing the pH in this range or increasing the temperature strengthened the binding of calcium to submicelles, similar to previous observations with individual caseins. However, the enthalpy change obtained from the temperature dependence was considerably greater than that reported for alpha s1- and beta-caseins. Furthermore, the elution profiles for 45Ca in milk salt solutions were decidedly different from those in CaCl2 or calcium phosphate buffers and the affinities were also greater. For example, at pH 6.7 and 30 degrees C the average dissociation constant for the submicelle-calcium complex is 0.074 mM for CaCl2 and calcium phosphate buffers, vs 0.016 mM for the milk salt solution. The asymmetric frontal boundaries and higher average affinities observed with milk salts may be due to binding of calcium salts with greater affinity in addition to the binding of free Ca2+ in these solutions

  19. The role of calcium in human aging.

    Science.gov (United States)

    Beto, Judith A

    2015-01-01

    Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance. PMID:25713787

  20. 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

  1. Bone healing around nanocrystalline hydroxyapatite, deproteinized bovine bone mineral, biphasic calcium phosphate, and autogenous bone in mandibular bone defects

    DEFF Research Database (Denmark)

    Broggini, Nina; Bosshardt, Dieter D; Jensen, Simon S;

    2015-01-01

    with nanocrystalline hydroxyapatite (HA-SiO), deproteinized bovine bone mineral (DBBM), biphasic calcium phosphate (BCP) with a 60/40% HA/β-TCP (BCP 60/40) ratio, or particulate autogenous bone (A) for histological and histomorphometric analysis. At 2 weeks, percent filler amongst the test groups (DBBM (35.65%), HA...

  2. Beam quality measure for vector beams.

    Science.gov (United States)

    Ndagano, Bienvenu; Sroor, Hend; McLaren, Melanie; Rosales-Guzmán, Carmelo; Forbes, Andrew

    2016-08-01

    Vector beams have found a myriad of applications, from laser materials processing to microscopy, and are now easily produced in the laboratory. They are usually differentiated from scalar beams by qualitative measures, for example, visual inspection of beam profiles after a rotating polarizer. Here we introduce a quantitative beam quality measure for vector beams and demonstrate it on cylindrical vector vortex beams. We show how a single measure can be defined for the vector quality, from 0 (purely scalar) to 1 (purely vector). Our measure is derived from a quantum toolkit, which we show applies to classical vector beams. PMID:27472580

  3. STIM1 is a Calcium Sensor Specialized for Digital Signaling

    OpenAIRE

    Bird, Gary S.; Hwang, Sung-Yong; Smyth, Jeremy T.; Fukushima, Miwako; Boyles, Rebecca R.; Putney, James W.

    2009-01-01

    When cells are activated by calcium-mobilizing agonists at low, physiological concentrations, the resulting calcium signals generally take the form of repetitive regenerative discharges of stored calcium, termed calcium oscillations [1]. These intracellular calcium oscillations have long fascinated biologists as representing a mode of digitized intracellular signaling. Recent work has highlighted the role of calcium influx as an essential component of calcium oscillations [2]. This influx occ...

  4. Beam propagation

    International Nuclear Information System (INIS)

    The main part of this thesis consists of 15 published papers, in which the numerical Beam Propagating Method (BPM) is investigated, verified and used in a number of applications. In the introduction a derivation of the nonlinear Schroedinger equation is presented to connect the beginning of the soliton papers with Maxwell's equations including a nonlinear polarization. This thesis focuses on the wide use of the BPM for numerical simulations of propagating light and particle beams through different types of structures such as waveguides, fibers, tapers, Y-junctions, laser arrays and crystalline solids. We verify the BPM in the above listed problems against other numerical methods for example the Finite-element Method, perturbation methods and Runge-Kutta integration. Further, the BPM is shown to be a simple and effective way to numerically set up the Green's function in matrix form for periodic structures. The Green's function matrix can then be diagonalized with matrix methods yielding the eigensolutions of the structure. The BPM inherent transverse periodicity can be untied, if desired, by for example including an absorptive refractive index at the computational window edges. The interaction of two first-order soliton pulses is strongly dependent on the phase relationship between the individual solitons. When optical phase shift keying is used in coherent one-carrier wavelength communication, the fiber attenuation will suppress or delay the nonlinear instability. (orig.)

  5. Performance of an rf beam monitor on the NBS-Los Alamos racetrack microtron

    International Nuclear Information System (INIS)

    A prototype rf beam-position, current, and phase monitor has been used on the 100-keV injector beamline of the racetrack microtron (RTM) where performance was measured with the chopped and bunched beam. This monitor works with both a pulsed beam and a cw beam. The pulsed beam consists of beam pulses with a FWHM of 40 ns. The rf beam monitor was tested with beam currents from approx. 50 to 600 μA. The rf beam monitor will be described and its performance will be reported. 6 refs., 5 figs

  6. Clogging and Cementation Caused by Calcium or Iron Biogrouts

    Science.gov (United States)

    Ivanov, V.; Chu, J.; Naeimi, M.

    2012-12-01

    Chemical grouts are often used to reduce the hydraulic conductivity of soil for seepage control purposes. However, chemical grouts can be expensive and environmentally unfriendly. Therefore, two new biogrouts were tested for their bioclogging and biocementation properties. The first was calcium-based biogrout, which contained urease-producing bacteria, calcium chloride and urea for the crystallization of calcite due to enzymatic hydrolysis of urea. The second was iron-based biogrout, which consisted of urease-producing bacteria, ferric chelate, and urea for the precipitation of ferric hydroxide and carbonate due to enzymatic hydrolysis of urea. The permeability of sand (P, 10^-5 m/s), treated with calcium-based biogrout, linearly decreased as a function of the content of precipitated calcium (C, % w/w) according to the following equation: P = 5.1 - 4.0 C. Meanwhile, the permeability of sand treated with iron-based biogrout dropped to 2.7x10^-6 m/s at content of precipitated iron (F, % w/w) about 0.35 % w/w , by the equation: P = 5.1 - 14.6 F , and then slowly decreased to 1.4x10^-7 m/s at content of precipitated iron 1.8% w/w by the following equation: P = 0.36 - 0.23F. Both biogrouts have approximately same efficiency in the reduction of permeability of sand to low values. However, the mechanisms of bioclogging are probably different because the reduction of permeability by calcium-based biogrout was described by linear function of precipitated calcium but the reduction of permeability by iron-based biogrout showed two steps of the clogging. Different functions and mechanisms were related probably to the different type of precipitates. The images of biogrouted sand samples show that calcium-based biogrout produced white amorphous or crystallised calcium carbonate, while iron-based biogrout produced gel-like brown precipitate without visible crystals. The unconfined compressive strengths of the sand treated with different biogrouts (Y, kPa) increased by power

  7. Fortification of all-purpose wheat-flour tortillas with calcium lactate, calcium carbonate, or calcium citrate is acceptable.

    Science.gov (United States)

    Romanchik-Cerpovicz, Joelle E; McKemie, Rebecca J

    2007-03-01

    Fortification helps provide adequate nutrients for individuals not meeting daily needs. Foods may be fortified with calcium to assist individuals with lactose intolerance and others preferring not to consume traditional forms of dairy. This study examined the quality of all-purpose wheat-flour tortillas fortified with calcium lactate, calcium carbonate, or calcium citrate. These tortillas were compared to similarly prepared nonfortified flour tortillas (control) and commercial nonfortified flour tortillas. Calcium-fortified tortillas contained 114 mg elemental calcium per standard serving (48 g tortilla), an 8.6-fold increase compared to nonfortified tortillas. Moisture contents and rollabilities of all tortillas were similar. Consumers (N=87) evaluated each tortilla in duplicate using a hedonic scale and reported liking the appearance, texture, flavor, aftertaste, and overall acceptability of all tortillas. However, the appearance of control tortillas was preferred over commercial tortillas (Ptortillas or those fortified with calcium carbonate was preferred over the control (Ptortillas, suggesting that appearance and aftertaste may not influence willingness to purchase. Overall, this study shows that fortification of flour tortillas with various forms of calcium is a feasible alternative calcium source. PMID:17324671

  8. Operational test of micro-oven for 48Ca beam

    Science.gov (United States)

    Ozeki, K.; Kageyama, T.; Kidera, M.; Higurashi, Y.; Nakagawa, T.

    2014-02-01

    In order to supply a high-intensity and stable 48Ca beam from the RIKEN 18-GHz electron cyclotron resonance ion source, we are conducting operational tests of a micro-oven. A mixture of CaO and Al powders is placed into the crucible of the micro-oven and heated to produce metallic calcium by a reductive reaction. The successful production of a calcium beam was confirmed. In addition, we reduced the material consumption rate by using a so-called "hot liner," and we enhanced the beam intensity by applying a negative voltage bias to the micro-oven, the effect of which is similar to the effect of a "biased disk."

  9. Funnel-web spider venom and a toxin fraction block calcium current expressed from rat brain mRNA in Xenopus oocytes.

    OpenAIRE

    Lin, J. W.; Rudy, B.; Llinás, R

    1990-01-01

    Injection of rat brain mRNA into Xenopus oocytes has been shown to induce a calcium current (ICa) that is insensitive to dihydropyridine and omega-conotoxin. We examined the effect of funnel-web spider venom on two aspects of this expressed ICa: (i) the calcium-activated chloride current [ICl(Ca)] and (ii) the currents carried by barium ions through calcium channels (IBa). In the presence of 1.8 mM extracellular calcium, ICl(Ca) tail current became detectable between -30 and -40 mV from a hol...

  10. Transmission of the Neutral Beam Heating Beams at TJ-II

    International Nuclear Information System (INIS)

    Neutral beam injection heating has been development for the TJ-II stellarator. The beam has a port-through power between 700-1500 kW and injection energy 40 keV. The sensibility of the injection system to the changes of several parameters is analysed. Beam transmission is limited by losses processes since beam is born into the ions source until is coming into the fusion machine. For the beam transmission optimization several beam diagnostics have been developed. A carbon fiber composite (CFC) target calorimeter has been installed at TJ-II to study in situ the power density distribution of the neutral beams. The thermographic print of the beam can be recorded and analysed in a reliable way due to the highly anisotropic thermal conductivity of the target material. With the combined thermographic and calorimetric measurements it has been possible to determine the power density distribution of the beam. It has been found that a large beam halo is present, which can be explained by the extreme misalignment of the grids. This kind of halo has a deleterious effect on beam transport and must be minimized in order to improve the plasma heating capability of the beams. (Author) 155 refs

  11. Biphasic calcium phosphate in periapical surgery

    OpenAIRE

    Suneelkumar, Chinni; Datta, Krithika; Manali R Srinivasan; Kumar, Sampath T

    2008-01-01

    Calcium phosphate ceramics like hydroxyapatite and β -tricalcium phosphate (β -TCP) possess mineral composition that closely resembles that of the bone. They can be good bone substitutes due to their excellent biocompatibility. Biphasic calcium phosphate is a bone substitute which is a mixture of hydroxyapatite and β -tricalcium phosphate in fixed ratios. Studies have demonstrated the osteoconductive potential of this composition. This paper highlights the clinical use of biphasic calcium pho...

  12. 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.

  13. Gravity, calcium, and bone - Update, 1989

    Science.gov (United States)

    Arnaud, Sara B.; Morey-Holton, Emily

    1990-01-01

    Recent results obtained on skeletal adaptation, calcium metabolism, and bone browth during short-term flights and ground simulated-microgravity experiments are presented. Results demonstrate that two principal components of calcium metabolism respond within days to changes in body position and to weightlessness: the calcium endocrine system and bone characteristics. Furthermore, results of recent studies imply that bone biomechanics are more severely affected by spaceflight exposures than is the bone mass.

  14. 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...

  15. Overbased Calcium sulfonate Detergent Technology Overview

    Institute of Scientific and Technical Information of China (English)

    MA Qing-gao; MUIR Ronald J.

    2009-01-01

    Overbased calcium sulfonate is used widely as detergent in automotive and marine lubricants, as well as various industrial oil applications. In this paper, the process to produce overbased calcium sulfonate is overviewed. The sulfonate structure and molecular weight and its molecular weight distribution, the enclosed calcium carbonate nanoparticle size and crystalline structure, properties of the carrier oil, all influence its properties, such as stability, viscosity, and detergency of the system.

  16. Calcium carboorthovanadate - a new compound with the apa

    International Nuclear Information System (INIS)

    Data on calcium carboorthovanadate, Ca10(VO4)6CO3, a new compound with an appatite structure based on calcium orthovanadate, are reported. The synthesis has been conducted in a stoichiometric mixture of finely ground calcium carbonate and calcium orthovanadate. It is found that calcium carboorthovanadate belongs to the hexagonal syngony and has an apatite structure. An analysis of the infrared spectra of initial compounds and calcium carboorthovanadate confirmed the presence of carbonate (CO3)2- and orthovanadate (VO4)3 groupings in the latter. On heating in air, beginning with 450 deg C calcium carboorthovanadate decomposes at a slow rate into calcium oxide, calcium orthovanadate, and carbon dioxide

  17. The effect of GlycoPEGylation on the physical stability of human rFVIIa with increasing calcium chloride concentration

    DEFF Research Database (Denmark)

    Plesner, Bitten; Westh, Peter; Hvidt, Søren;

    2011-01-01

    The effects of calcium chloride on the structural, kinetic and thermal stability of recombinant human factor VIIa (rFVIIa) were investigated using rFVIIa and two GlycoPEGylated recombinant human FVIIa derivatives, a linear 10 kDa PEG and a branched 40 kDa PEG, respectively. Three different CaCl(2...... thermally induced aggregation of the GlycoPEGylated rFVIIa compounds is unaffected by an increasing calcium chloride concentration....

  18. Calcium supplements: do they help or harm?

    Science.gov (United States)

    Manson, Joann E; Bassuk, Shari S

    2014-01-01

    Current recommendations for calcium intake call for 1,000 mg per day for women ages 19-50 and 1,200 mg per day for women over age 50 to ensure bone health. Given recent concerns that calcium supplements may raise risk for cardiovascular disease and kidney stones, women should aim to meet this recommendation primarily by eating a calcium-rich diet and taking calcium supplements only if needed to reach the RDA goal (often only approximately 500 mg per day in supplements is required). PMID:23880796

  19. 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...

  20. Peroxisome is a reservoir of intracellular calcium.

    Science.gov (United States)

    Raychaudhury, Bikramjit; Gupta, Shreedhara; Banerjee, Shouvik; Datta, Salil C

    2006-07-01

    We have examined fura 2-loaded purified peroxisomes under confocal microscope to prove that this mammalian organelle is a store of intracellular calcium pool. Presence of calcium channel and vanadate sensitive Ca(2+)-ATPase in the purified peroxisomal membrane has been demonstrated. We have further observed that machineries to maintain calcium pool in this mammalian organelle are impaired during infection caused by Leishmania donovani. Results reveal that peroxisomes have a merit to play a significant role in the metabolism of intracellular calcium. PMID:16713100

  1. How calcium makes endocytic receptors attractive

    DEFF Research Database (Denmark)

    Andersen, Christian B F; Moestrup, Søren K

    2014-01-01

    receptor. Endosomal acidification and calcium efflux lead to the essential ligand-receptor affinity switch and separation. Recent data, including crystal structures of receptor-ligand complexes, now reveal how calcium, in different types of domain scaffolds, functions in a common way as a removable...... 'lynchpin' that stabilizes favorable positioning of ligand-attractive receptor residues. In addition to explaining how calcium depletion can cause ligand-receptor dissociation, the new data add further insight into how acidification contributes to dissociation through structural changes that affect the...... receptor calcium sites....

  2. 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.

  3. 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

  4. Unexpectedly large charge radii of neutron-rich calcium isotopes

    Science.gov (United States)

    Garcia Ruiz, R. F.; Bissell, M. L.; Blaum, K.; Ekström, A.; Frömmgen, N.; Hagen, G.; Hammen, M.; Hebeler, K.; Holt, J. D.; Jansen, G. R.; Kowalska, M.; Kreim, K.; Nazarewicz, W.; Neugart, R.; Neyens, G.; Nörtershäuser, W.; Papenbrock, T.; Papuga, J.; Schwenk, A.; Simonis, J.; Wendt, K. A.; Yordanov, D. T.

    2016-06-01

    Despite being a complex many-body system, the atomic nucleus exhibits simple structures for certain `magic’ numbers of protons and neutrons. The calcium chain in particular is both unique and puzzling: evidence of doubly magic features are known in 40,48Ca, and recently suggested in two radioactive isotopes, 52,54Ca. Although many properties of experimentally known calcium isotopes have been successfully described by nuclear theory, it is still a challenge to predict the evolution of their charge radii. Here we present the first measurements of the charge radii of 49,51,52Ca, obtained from laser spectroscopy experiments at ISOLDE, CERN. The experimental results are complemented by state-of-the-art theoretical calculations. The large and unexpected increase of the size of the neutron-rich calcium isotopes beyond N = 28 challenges the doubly magic nature of 52Ca and opens new intriguing questions on the evolution of nuclear sizes away from stability, which are of importance for our understanding of neutron-rich atomic nuclei.

  5. Unexpectedly large charge radii of neutron-rich calcium isotopes

    CERN Document Server

    Garcia Ruiz, R F; Blaum, K; Ekström, A; Frömmgen, N; Hagen, G; Hammen, M; Hebeler, K; Holt, J D; Jansen, G R; Kowalska, M; Kreim, K; Nazarewicz, W; Neugart, R; Neyens, G; Nörtershäuser, W; Papenbrock, T; Papuga, J; Schwenk, A; Simonis, J; Wendt, K A; Yordanov, D T

    2016-01-01

    Despite being a complex many-body system, the atomic nucleus exhibits simple structures for certain ‘magic’ numbers of protons and neutrons. The calcium chain in particular is both unique and puzzling: evidence of doubly magic features are known in 40,48Ca, and recently suggested in two radioactive isotopes, 52,54Ca. Although many properties of experimentally known calcium isotopes have been successfully described by nuclear theory, it is still a challenge to predict the evolution of their charge radii. Here we present the first measurements of the charge radii of 49,51,52Ca, obtained from laser spectroscopy experiments at ISOLDE, CERN. The experimental results are complemented by state-of-the-art theoretical calculations. The large and unexpected increase of the size of the neutron-rich calcium isotopes beyond N = 28 challenges the doubly magic nature of 52Ca and opens new intriguing questions on the evolution of nuclear sizes away from stability, which are of importance for our understanding of neutron-...

  6. Calcium Absorption from Fortified Ice Cream Formulations Compared with Calcium Absorption from Milk

    OpenAIRE

    van der Hee, Regine M.; Miret, Silvia; Slettenaar, Marieke; Duchateau, Guus S.M.J.E.; Rietveld, Anton G.; Wilkinson, Joy E.; Quail, Patricia J.; Berry, Mark J.; Dainty, Jack R.; Teucher, Birgit; Fairweather-Tait, Susan J

    2009-01-01

    Objective Optimal bone mass in early adulthood is achieved through appropriate diet and lifestyle, thereby protecting against osteoporosis and risk of bone fracture in later life. Calcium and vitamin D are essential to build adequate bones, but calcium intakes of many population groups do not meet dietary reference values. In addition, changes in dietary patterns are exacerbating the problem, thereby emphasizing the important role of calcium-rich food products. We have designed a calcium-fort...

  7. Association of Urinary Calcium Excretion with Serum Calcium and Vitamin D Levels

    OpenAIRE

    A Rathod; Bonny, O; Guessous, I; Suter, P M; Conen, D; Erne, P; Binet, I; Gabutti, L; Gallino, A; Muggli, F; Hayoz, D; Pechere-Bertschi, A; Paccaud, F.; Burnier, M.; Bochud, M

    2015-01-01

    BACKGROUND AND OBJECTIVES: Population-based data on urinary calcium excretion are scarce. The association of serum calcium and circulating levels of vitamin D [25(OH)D2 or D3] with urinary calcium excretion in men and women from a population-based study was explored. DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS: Multivariable linear regression was used to explore factors associated with square root-transformed 24-hour urinary calcium excretion (milligrams per 24 hours) taken as the dep...

  8. Drosophila mushroom body Kenyon cells generate spontaneous calcium transients mediated by PLTX-sensitive calcium channels.

    OpenAIRE

    Jiang, Shaojuan Amy; Campusano, Jorge M.; Su, Hailing; O'Dowd, Diane K.

    2005-01-01

    Spontaneous calcium oscillations in mushroom bodies of late stage pupal and adult Drosophila brains have been implicated in memory consolidation during olfactory associative learning. This study explores the cellular mechanisms regulating calcium dynamics in Kenyon cells, principal neurons in mushroom bodies. Fura-2 imaging shows that Kenyon cells cultured from late stage Drosophila pupae generate spontaneous calcium transients in a cell autonomous fashion, at a frequency similar to calcium o...

  9. The Electronic Structure of Calcium

    DEFF Research Database (Denmark)

    Jan, J.-P.; Skriver, Hans Lomholt

    1981-01-01

    The electronic structure of calcium under pressure is re-examined by means of self-consistent energy band calculations based on the local density approximation and using the linear muffin-tin orbitals (LMTO) method with corrections to the atomic sphere approximation included. At zero pressure.......149 Ryd, respectively, relative to the s band, give the best possible agreement. Under increasing pressure the s and p electrons are found to transfer into the d band, and Ca undergoes metal-semimetal-metal electronic transitions. Calculations of the bandstructure and the electronic pressure, including...

  10. Physicochemical investigation of calcium bromtechnetate

    International Nuclear Information System (INIS)

    Calcium hexabromotechnetate is extracted for the first time and its composition corresponding to the CaTcBr6 formula is determined. Using the thermal analysis method the anhydrous salt stability boundaries are found. The X-ray phase analysis has shown the compound to be isostructural with (NH4)2TcI6 and has a rhombic b.c.c. crystal lattice with the following parameters: a=10.39+-0.01, b=7.34+-0.01 and c=7.45+-0.001A. At 380-420 deg C CaTcBr6 decomposes to Tc, CaBr2 and Br

  11. Calcium Imaging Perspectives in Plants

    Directory of Open Access Journals (Sweden)

    Chidananda Nagamangala Kanchiswamy

    2014-03-01

    Full Text Available The calcium ion (Ca2+ is a versatile intracellular messenger. It provides dynamic regulation of a vast array of gene transcriptions, protein kinases, transcription factors and other complex downstream signaling cascades. For the past six decades, intracellular Ca2+ concentration has been significantly studied and still many studies are under way. Our understanding of Ca2+ signaling and the corresponding physiological phenomenon is growing exponentially. Here we focus on the improvements made in the development of probes used for Ca2+ imaging and expanding the application of Ca2+ imaging in plant science research.

  12. Barium calcium hydroxyapatite solid solutions

    International Nuclear Information System (INIS)

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

  13. Calcium

    Science.gov (United States)

    ... for lunch; and beans, salsa, taco sauce, and cheese for dinner. Create mini-pizzas by topping whole-wheat English muffins or bagels with pizza sauce and low-fat mozzarella or soy cheese. Try whole-grain crackers with low-fat cheese ...

  14. Calcium

    Science.gov (United States)

    ... eliminates in urine, feces, and sweat. These include consumption of alcohol- and caffeine-containing beverages as well as intake ... and older 2,000 mg Pregnant and breastfeeding teens 3,000 mg Pregnant and breastfeeding adults 2, ...

  15. High current precision long pulse electron beam position monitor

    CERN Document Server

    Nelson, S D; Fessenden, T J; Holmes, C

    2000-01-01

    Precision high current long pulse electron beam position monitoring has typically experienced problems with high Q sensors, sensors damped to the point of lack of precision, or sensors that interact substantially with any beam halo thus obscuring the desired signal. As part of the effort to develop a multi-axis electron beam transport system using transverse electromagnetic stripline kicker technology, it is necessary to precisely determine the position and extent of long high energy beams for accurate beam position control (6 - 40 MeV, 1 - 4 kA, 2 μs beam pulse, sub millimeter beam position accuracy.) The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (< 20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt position measurements.

  16. Inhibitory efficacy of calcium cyanamide on the pathogens of replant diseases in strawberry

    Institute of Scientific and Technical Information of China (English)

    WANG Lijing; HU Tongle; JI Lijing; CAO Keqiang

    2007-01-01

    Replant diseases in strawberry caused by Rhizoctonia solani,Fusarium oxysporum and Verticillium dahliae are serious problems for its sustainable production under continuous cropping.This research studied the inhibitory effect of calcium cyanamide on pathogenic fungi in Petri dishes and on sterilized soil.Results indicated that calcium cyanamide had an obvious inhibitory effect on three pathogens on potato dextrose agar (PDA) plates.Among them,the inhibitory effect on Rhizoctonia solani was the highest.As the concentrations of calcium cyanamide was increased from 0.1 to 10 mg/mL,the inhibition rate on mycelial growth increased from -1.43% to 100%.Inhibitory effects on Fusarium oxysporum and Verticillium dahliae also existed on Petri dishes but to a lesser extent.Similar results were also observed in sterilized soil.When the concentration of calcium cyanamide in sterilized soil was 0.1%,the inhibitory effect on Fusarium oxysporum and Verticillium dahliae was 68.46% and 54.46%,respectively.The inhibitive effect of calcium cyanamide on Fusariurn oxysporum and Verticillium dahliae increased quickly as the soil moisture changed from 10% to 40% for Verticillium dahliae and from 10% to 60% forFusarium oxysporum.This indicated that the inhibitive effect of calcium cyanamide could be influenced greatly by the moisture content in the soil.

  17. Colliding beam physics at Fermilab: interaction regions, beam storage, antiproton cooling, production, and colliding

    Energy Technology Data Exchange (ETDEWEB)

    Walker, J.K. (ed.)

    1977-01-01

    The purpose of the colliding beams experment department at Fermilab was to bring about collisions of the stored beams in the energy doubler/saver and main ring, and construct experimental areas with appropriate detectors. To explore the feasibility of using the main ring as a storage device, several studies were carried out to investigate beam growth, loss, and the backgrounds in detectors at possible intersection regions. This range of developments constituted the major topics at the 1977 Summer Study reported here. Emphasis in part one is on interaction regions, beam storage, antiproton cooling, production, and colliding. 40 papers from this part are included in the data base. (GHT)

  18. Hypercalcemia Associated with Calcium Supplement Use: Prevalence and Characteristics in Hospitalized Patients

    Directory of Open Access Journals (Sweden)

    Maria C. Machado

    2015-03-01

    Full Text Available Background: The ingestion of large amounts of milk and antacids to treat peptic ulcer disease was a common cause of hypercalcemia in the past (the “milk-alkali syndrome”. The current popularity of calcium and supplements has given rise to a similar problem. Objectives: To evaluate the prevalence and characteristics of hypercalcemia induced by calcium intake (“calcium supplement syndrome”; or CSS in hospitalized patients. Methods: We conducted a retrospective; electronic health record (EHR-based review of patients with hypercalcemia over a 3-year period. Diagnosis of CSS was based on the presence of hypercalcemia; a normal parathyroid hormone (PTH level; renal insufficiency; metabolic alkalosis; a history of calcium intake; and documented improvement with treatment. Results: Of the 72 patients with non-PTH mediated hypercalcemia; 15 (20.8% satisfied all the criteria for the diagnosis of CSS. Calcium; vitamin D; and multivitamin ingestion were significantly associated with the diagnosis (p values < 0.0001; 0.014; and 0.045 respectively; while the presence of hypertension; diabetes; and renal insufficiency showed a trend towards statistical significance. All patients received intravenous fluids; and six (40% received calcium-lowering drugs. The calcium level at discharge was normal 12 (80% of patients. The mean serum creatinine and bicarbonate levels decreased from 2.4 and 35 mg/dL on admission respectively; to 1.6 mg/dL and 25.6 mg/dL at discharge respectively. Conclusion: The widespread use of calcium and vitamin D supplementation can manifest as hypercalcemia and worsening of kidney function in susceptible individuals. Awareness among health care professionals can lead to proper patient education regarding these health risks.

  19. Beam halo in high-intensity beams

    International Nuclear Information System (INIS)

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam

  20. 40 CFR 180.547 - Prohexadione calcium; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ..., straw 1 1.2 Hog, kidney 0.10 Hog, meat byproducts, except kidney 0.05 Horse, kidney 0.10 Horse, meat byproducts, except kidney 0.05 Peanut 1.0 Peanut, hay 0.60 Sheep, kidney 0.10 Sheep, meat byproducts, except....10 Cattle, meat byproducts, except kidney 0.05 Fruit, pome, group 11 3.0 Goat, kidney 0.10 Goat,...

  1. Calcium and Vitamin D: Important at Every Age

    Science.gov (United States)

    ... supported by your browser. Home Bone Basics Nutrition Calcium and Vitamin D: Important at Every Age Publication ... Osteoporosis Program For Your Information The Role of Calcium Calcium is needed for our heart, muscles, and ...

  2. LEDA beam diagnostics instrumentation: Beam current measurement

    International Nuclear Information System (INIS)

    The Low Energy Demonstration Accelerator (LEDA) facility located at Los Alamos National Laboratory (LANL) accelerates protons to an energy of 6.7 MeV and current of 100 mA operating in either a pulsed or cw mode. Two types of current measurements are used. The first is an AC or pulsed-current measurement which uses three LANL built toroids. They are placed in the beamline in such a way as to measure important transmission parameters and act as a differential current-loss machine protection system. The second system is a DC current measurement used to measure cw beam characteristics and uses toroids from Bergoz Inc. There are two of these systems, so they can also be used for transmission measurements. The AC system uses custom processing electronics whereas the DC system uses a modified Bergoz registered electronics system. Both systems feature data acquisition via a series of custom TMS320C40 Digital Signal Processing (DSP) boards. Of special interest to this paper is the operation of these systems, the calibration technique, the differential current loss measurements and fast-protection processing, current droop characteristics for the AC system, and existing system noise levels. This paper will also cover the DSP system operations and their interaction with the main accelerator control system

  3. Clinical validation of dialysable calcium in relation to other methods of serum calcium measurement.

    OpenAIRE

    Prince, R. L.; Langton, S R

    1985-01-01

    Dialysable calcium (CaD) values were measured by a simple technique not interfered with by protein bound calcium and validation attempted by comparison with concentrations of ionised calcium (CaI) and clinical categorisation. CaD values were also compared with total calcium (CaT) and albumin adjusted calcium (CaA) concentrations. The normal ranges for CaD, CaT, CaA, and CaI were calculated from the results in healthy blood donors. In 50 normal subjects CaD was more highly correlated with CaI ...

  4. Calcium measurements with electron probe X-ray and electron energy loss analysis

    International Nuclear Information System (INIS)

    This paper presents a broad survey of the rationale for electron probe X-ray microanalysis (EPXMA) and the various methods for obtaining qualitative and quantitative information on the distribution and amount of elements, particularly calcium, in cryopreserved cells and tissues. Essential in an introductory consideration of microanalysis in biological cryosections is the physical basis for the instrumentation, fundamentals of X-ray spectrometry, and various analytical modes such as static probing and X-ray imaging. Some common artifacts are beam damage and contamination. Inherent pitfalls of energy dispersive X-ray systems include Si escape peaks, doublets, background, and detector calibration shifts. Quantitative calcium analysis of thin cryosections is carried out in real time using a multiple least squares fitting program on filtered X-ray spectra and normalizing the calcium peak to a portion of the continuum. Recent work includes the development of an X-ray imaging system where quantitative data can be retrieved off-line. The minimum detectable concentration of calcium in biological cryosections is approximately 300 mumole kg dry weight with a spatial resolution of approximately 100 A. The application of electron energy loss (EELS) techniques to the detection of calcium offers the potential for greater sensitivity and spatial resolution in measurement and imaging. Determination of mass thickness with EELS can facilitate accurate calculation of wet weight concentrations from frozen hydrated and freeze-dried specimens. Calcium has multiple effects on cell metabolism, membrane transport and permeability and, thus, on overall cell physiology or pathophysiology. Cells can be rapidly frozen for EPXMA during basal or altered functional conditions to delineate the location and amount of calcium within cells. 72 references

  5. An Intracellular Calcium Oscillations Model Including Mitochondrial Calcium Cycling

    Institute of Scientific and Technical Information of China (English)

    SHI Xiao-Min; LIU Zeng-Rong

    2005-01-01

    @@ Calcium is a ubiquitous second messenger. Mitochondria contributes significantly to intracellular Ca2+ dynamics.The experiment of Kaftan et al. [J. Biol. Chem. 275(2000) 25465] demonstrated that inhibiting mitochondrial Ca2+ uptake can reduce the frequency of cytosolic Ca2+ concentration oscillations of gonadotropes. By considering the mitochondrial Ca2+ cycling we develop a three-variable model of intracellular Ca2+ oscillations based on the models of Atri et al. [Biophys. J. 65 (1993) 1727] and Falcke et al. [Biophys. J. 77 (1999) 37]. The model reproduces the fact that mitochondrial Ca2+ cycling increases the frequency of cytosolic Ca2+ oscillations, which accords with Kaftan's results. Moreover the model predicts that when the mitochondria overload with Ca2+, the cytosolic Ca2+ oscillations vanish, which may trigger apoptosis.

  6. Beam imaging sensor

    Energy Technology Data Exchange (ETDEWEB)

    McAninch, Michael D.; Root, Jeffrey J.

    2016-07-05

    The present invention relates generally to the field of sensors for beam imaging and, in particular, to a new and useful beam imaging sensor for use in determining, for example, the power density distribution of a beam including, but not limited to, an electron beam or an ion beam. In one embodiment, the beam imaging sensor of the present invention comprises, among other items, a circumferential slit that is either circular, elliptical or polygonal in nature.

  7. Bone Up on the Need for Calcium.

    Science.gov (United States)

    Mann, Peggy

    1987-01-01

    Most grade-schoolers drink milk at each meal, but teens, especially girls, often switch to carbonated soda at mealtime just as they should be building up their bone bank of calcium. Why calcium is important and how to get enough of it are covered. (MT)

  8. 21 CFR 182.8217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.8217 Section 182.8217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  9. Calcium, snails, and birds: a case study

    Directory of Open Access Journals (Sweden)

    R. Mänd

    2000-10-01

    Full Text Available Recent studies have shown that wild birds breeding in acidified areas have difficulties with obtaining sufficient calcium for their eggshells, and that the cause of it is the shortage of land snails. Many birds have to search for Ca-rich snail shells on a daily basis during egg production. Molluscs depend on litter calcium, which has decreased due to acidification of the environment. Calcium limitation may be a widespread phenomenon also in non-acidified, naturally Ca-poor areas. The problem is that while in the latter areas the time for development of specific adaptations may have been sufficient, then in acidified areas, on the contrary, calcium shortage is a recent phenomenon. Therefore, since the extent of calcium limitation in non-acidified areas is hard to derive from observational data, experimental approach is needed. We provide experimental evidence that specific calcium deficit does affect reproductive traits also in the birds breeding in naturally base-poor habitats. Our study was conducted in a heterogeneous woodland area in Estonia containing deciduous forest patches as well as base-poor pine forest with low snail abundance. Ca supplementation, using snail shell and chicken eggshell fragments, was carried out for pied flycatchers and great tits. Extra calcium affected positively several reproductive traits like egg volume and eggshell thickness, start of breeding, and fledglings’ parameters. The negative relationship between calcium availability and lay-date suggests that birds adjust their breeding tactics to conditions of Ca deficiency, for example, by postponing laying.

  10. Calcium Free Asbestos for Fuel Cells

    Science.gov (United States)

    Snitzer, B. A.

    1983-01-01

    Organic-acid salt removes unwanted calcium without weakening asbestos. Asbestos mixed with disodium ethylene diamine tetraacetic acid (disodium EDTA) in water and agitated for 2 hours. After disodium EDTA solution is drained away, asbestos contains only 0.02 to 0.1 percent calcium. Fiber structure of asbestos unaffected.

  11. 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

  12. Stochastic Kinetics of Intracellular Calcium Oscillations

    Institute of Scientific and Technical Information of China (English)

    陈昌胜; 曾仁端

    2003-01-01

    A stochastic model of intracellular calcium oscillations is put forward by taking into account the random opening-closing of Ca2+ channels in endoplasmic reticulum (ER) membrane. The numerical results of the stochastic model show simple and complex calcium oscillations, which accord with the experiment results.

  13. 21 CFR 172.410 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Anticaking Agents § 172.410 Calcium...

  14. Engineering calcium oxalate crystal formation in Arabidopsis

    Science.gov (United States)

    Many plants accumulate crystals of calcium oxalate. Just how these crystals form remains unknown. To gain insight into the mechanisms regulating calcium oxalate crystal formation, a crystal engineering approach was initiated utilizing the non-crystal accumulating plant, Arabidopsis. The success of t...

  15. 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.

  16. Particularities of thermal expansion of calcium vanadates

    International Nuclear Information System (INIS)

    Temperature dependence of unit cell parameters of calcium vanadates Ca(VO3)2, Ca2V2O7 and Ca3(VO4)2 is studied. It is shown that lattice parameters of meta- and pyrovanadates change monotonously. Lattice parameters of calcium orthovanadate change sharply and unmonotonously at 400-500 deg C

  17. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

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

  18. ALG-2, a multifunctional calcium binding protein?

    DEFF Research Database (Denmark)

    Tarabykina, Svetlana; Mollerup, Jens; Winding Gojkovic, P.;

    2004-01-01

    ALG-2 was originally discovered as a pro-apoptotic protein in a genetic screen. Due to its ability to bind calcium with high affinity it was postulated to provide a link between the known effect of calcium in programmed cell death and the molecular death execution machinery. This review article...

  19. 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.

  20. Indium sulfide precipitation from hydrochloric acid solutions of calcium and sodium chlorides

    International Nuclear Information System (INIS)

    The effect of precipitation duration, acid concentration, indium complexing with chloride ions on the process of indium sulfide chemical precipitation in hydrochloric acid solutions, precipitate composition and dispersity are studied. It is established that indium sulfide solubility increases in solutions with acid concentration exceeding 0.40-0.45 mol/l. Calcium and indium chloride addition to diluted hydrochloric solutions greatly increases the solubility of indium sulfide. The effect of calcium chloride on In2S3 solubility is higher than that of sodium chloride

  1. Effect of different retarders on the hydration of calcium sulfoaluminate eco-cement pastes

    OpenAIRE

    García-Maté, Marta; De la Torre, Ángeles G.; Aranda, Miguel A. G.; Santacruz, Isabel

    2014-01-01

    The manufacture of Calcium SulfoAluminate (CSA) cements is more environmentally friendly than that of OPC [1] as their production releases up to 40% less CO2 than the latter. The main performances of CSA cements are fast setting time, good-chemical resistance properties and high early strengths. CSA cements are prepared by mixing CSA clinker with different amounts of a calcium sulfate set regulator such as gypsum (CaSO4•2H2O), bassanite (CaSO4•½H2O), or anhydrite (CaSO4), or mixtures of th...

  2. Indoleamines and calcium channels influence morphogenesis in in vitro cultures of Mimosa pudica L.

    OpenAIRE

    Ramakrishna, Akula; Giridhar, Parvatam; Ravishankar, G.A.

    2009-01-01

    The present article reports the interplay of indoleamine neurohormones viz. serotonin, melatonin and calcium channels on shoot organogenesis in Mimosa pudica L. In vitro grown nodal segments were cultured on MS medium with B5 vitamins containing Serotonin (SER) and Melatonin (MEL) at 100 µM and indoleamine inhibitors viz. serotonin to melatonin conversion inhibitor p-chlorophenylalanine (p-CPA) at 40 µM, serotonin reuptake inhibitor (Prozac) 20 µM. In another set of experiment, calcium at 5 m...

  3. Application of Calcium Phosphate Materials in Dentistry

    Directory of Open Access Journals (Sweden)

    Jabr S. Al-Sanabani

    2013-01-01

    Full Text Available Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1 application of calcium phosphate into various fields in dentistry; (2 improving mechanical properties of calcium phosphate; (3 biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials such as hydroxyapatite and tricalcium phosphate which are currently used in dental and medical fields.

  4. Omega spectrometer ready for SPS beams

    CERN Multimedia

    1977-01-01

    Two different beams arrive into the Omega magnet: - a tagged photon beam for a charm search - experiment WA4 by the Bonn-CERN-Daresbury-Ecole Polytechnique-Glasgow-Lancaster-Manchester-Orsay-Sheffield Collaboration; - a separated hadron beam, at first for a beam-dump experiment - WA12 by the Birmingham-CERN-Ecole Polytechnique-MPI, Munich-Neuchâtel Collaboration. Beams of either negative or positive pions or kaons, protons or antiprotons, all at an energy around 40 GeV were made to impinge on a copper target where a shower of hadrons was produced and, on occasion, two muons which before detection passed through an iron absorber (not visible here). WA12 was completed in February 1977. At the centre, on top of the superconducting magnet, the hut containing the TV cameras, These observe the particle events occurring in the spark chambers in the magnet below.

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

    Science.gov (United States)

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

    2012-05-15

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

  6. An AC phase measuring interferometer for measuring dn/dT of fused silica and calcium fluoride at 193 nm

    Energy Technology Data Exchange (ETDEWEB)

    Shagam, R.N.

    1998-09-01

    A novel method for the measurement of the change in index of refraction vs. temperature (dn/dT) of fused silica and calcium fluoride at the 193 nm wavelength has been developed in support of thermal modeling efforts for the development of 193 nm-based photolithographic exposure tools. The method, based upon grating lateral shear interferometry, uses a transmissive linear grating to divide a 193 nm laser beam into several beam paths by diffraction which propagate through separate identical material samples. One diffracted order passing through one sample overlaps the undiffracted beam from a second sample and forms interference fringes dependent upon the optical path difference between the two samples. Optical phase delay due to an index change from heating one of the samples causes the interference fringes to change sinusoidally with phase. The interferometer also makes use of AC phase measurement techniques through lateral translation of the grating. Results for several samples of fused silica and calcium fluoride are demonstrated.

  7. Calcium: a code coupling tool

    International Nuclear Information System (INIS)

    Today, the calculation performances of computers allow the precise and global simulation of complex industrial processes such as the functioning of a nuclear reactor core. One can question the need for the elaboration of new global numerical models in order to make use of the overall capability of computers. Another less time consuming solution consist in the coupling of existing well validated numerical models in order to make them working together. This paper presents the basic principles of the coupling of numerical codes, the tools required, the Calcium tool for codes coupling and an example of application of this tool in the coupling of the THYC (EdF), COCCINELLE (EdF) and CATHARE (CEA-EdF-Framatome) codes for the modeling of the thermal-hydraulic and neutronic behaviour of a reactor core during accidental situation. (J.S.)

  8. Bivalves build their shells from amorphous calcium carbonate

    Science.gov (United States)

    Jacob, D. E.; Wirth, R.; Soldati, A. L.; Wehrmeister, U.

    2012-04-01

    One of the most common shell structures in the bivalve class is the prism and nacre structure. It is widely distributed amongst both freshwater and marine species and gives cultured pearls their sought-after lustre. In freshwater bivalves, both shell structures (prism and nacre) consist of aragonite. Formation of the shell form an amorphous precursor phase is a wide-spread strategy in biomineralization and presents a number of advantages for the organisms in the handling of the CaCO3 material. While there is already evidence that larval shells of some mollusk species use amorphous calcium carbonate (ACC) as a transient precursor phase for aragonite, the use of this strategy by adult animals was only speculated upon. We present results from in-situ geochemistry, Raman spectroscopy and focused-ion beam assisted TEM on three species from two different bivalve families that show that remnants of ACC can be found in shells from adult species. We show that the amorphous phase is not randomly distributed, but is systematically found in a narrow zone at the interface between periostracum and prism layer. This zone is the area where spherulitic CaCO3- structures protrude from the inner periostracum to form the initial prisms. These observations are in accordance with our earlier results on equivalent structures in freshwater cultured pearls (Jacob et al., 2008) and show that the original building material for the prisms is amorphous calcium carbonate, secreted in vesicles at the inner periostracum layer. Quantitative temperature calibrations for paleoclimate applications using bivalve shells are based on the Mg-Ca exchange between inorganic aragonite (or calcite) and water. These calibrations, thus, do not take into account the biomineral crystallization path via an amorphous calcium carbonate precursor and are therefore likely to introduce a bias (a so-called vital effect) which currently is not accounted for. Jacob et al. (2008) Geochim. Cosmochim. Acta 72, 5401-5415

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

    Science.gov (United States)

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

    2011-12-01

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

  10. A symplectic coherent beam-beam model

    International Nuclear Information System (INIS)

    We consider a simple one-dimensional model to study the effects of the beam-beam force on the coherent dynamics of colliding beams. The key ingredient is a linearized beam-beam kick. We study only the quadrupole modes, with the dynamical variables being the 2nd-order moments of the canonical variables q, p. Our model is self-consistent in the sense that no higher order moments are generated by the linearized beam-beam kicks, and that the only source of violation of symplecticity is the radiation. We discuss the round beam case only, in which vertical and horizontal quantities are assumed to be equal (though they may be different in the two beams). Depending on the values of the tune and beam intensity, we observe steady states in which otherwise identical bunches have sizes that are equal, or unequal, or periodic, or behave chaotically from turn to turn. Possible implications of luminosity saturation with increasing beam intensity are discussed. Finally, we present some preliminary applications to an asymmetric collider. 8 refs., 8 figs

  11. Literature in Focus Beta Beams: Neutrino Beams

    CERN Document Server

    2009-01-01

    By Mats Lindroos (CERN) and Mauro Mezzetto (INFN Padova, Italy) Imperial Press, 2009 The beta-beam concept for the generation of electron neutrino beams was first proposed by Piero Zucchelli in 2002. The idea created quite a stir, challenging the idea that intense neutrino beams only could be produced from the decay of pions or muons in classical neutrino beams facilities or in future neutrino factories. The concept initially struggled to make an impact but the hard work by many machine physicists, phenomenologists and theoreticians over the last five years has won the beta-beam a well-earned position as one of the frontrunners for a possible future world laboratory for high intensity neutrino oscillation physics. This is the first complete monograph on the beta-beam concept. The book describes both technical aspects and experimental aspects of the beta-beam, providing students and scientists with an insight into the possibilities o...

  12. Stationary digital chest tomosynthesis for coronary artery calcium scoring

    Science.gov (United States)

    Wu, Gongting; Wang, Jiong; Potuzko, Marci; Harman, Allison; Pearce, Caleb; Shan, Jing; Lee, Yueh Z.; Zhou, Otto; Lu, Jianping

    2016-03-01

    The coronary artery calcium score (CACS) measures the buildup of calcium on the coronary artery wall and has been shown to be an important predictor of the risk of coronary artery diseases (CAD). Currently CACS is measured using CT, though the relatively high cost and high radiation dose has limited its adoption as a routine screening procedure. Digital Chest Tomosynthesis (DCT), a low dose and low cost alternative to CT, and has been shown to achieve 90% of sensitivity of CT in lung disease screening. However commercial DCT requires long scanning time and cannot be adapted for high resolution gated cardiac imaging, necessary for CACS. The stationary DCT system (s- DCT), developed in our lab, has the potential to significantly shorten the scanning time and enables high resolution cardiac gated imaging. Here we report the preliminary results of using s-DCT to estimate the CACS. A phantom heart model was developed and scanned by the s-DCT system and a clinical CT in a phantom model with realistic coronary calcifications. The adapted fan-beam volume reconstruction (AFVR) method, developed specifically for stationary tomosynthesis systems, is used to obtain high resolution tomosynthesis images. A trained cardiologist segmented out the calcifications and the CACS was obtained. We observed a strong correlation between the tomosynthesis derived CACS and CT CACS (r2 = 0.88). Our results shows s-DCT imaging has the potential to estimate CACS, thus providing a possible low cost and low dose imaging protocol for screening and monitoring CAD.

  13. Production of precipitated calcium carbonate from calcium silicates and carbon dioxide

    International Nuclear Information System (INIS)

    The possibilities for reducing carbon dioxide emissions from the pulp and paper industry by calcium carbonation are presented. The current precipitated calcium carbonate (PCC) production uses mined, crushed calcium carbonate as raw materials. If calcium silicates were used instead, carbon dioxide emissions from the calcination of carbonates would be eliminated. In Finland, there could, thus, be a potential for eliminating 200 kt of carbon dioxide emissions per year, considering only the PCC used in the pulp and paper industry. A preliminary investigation of the feasibility to produce PCC from calcium silicates and the potential to replace calcium carbonate as the raw material was made. Calcium carbonate can be manufactured from calcium silicates by various methods, but only a few have been experimentally verified. The possibility and feasibility of these methods as a replacement for the current PCC production process was studied by thermodynamic equilibrium calculations using HSC software and process modelling using Aspen Plus[reg]. The results from the process modelling showed that a process that uses acetic acid for extraction of the calcium ions is a high potential option for sequestering carbon dioxide by mineral carbonation. The main obstacle seems to be the limited availability and relatively high price of wollastonite, which is a mineral with high calcium silicate content. An alternative is to use the more common, but also more complex, basalt rock instead

  14. Effect of calcium intake on urinary oxalate excretion in calcium stone-forming patients

    Directory of Open Access Journals (Sweden)

    Nishiura J.L.

    2002-01-01

    Full Text Available Dietary calcium lowers the risk of nephrolithiasis due to a decreased absorption of dietary oxalate that is bound by intestinal calcium. The aim of the present study was to evaluate oxaluria in normocalciuric and hypercalciuric lithiasic patients under different calcium intake. Fifty patients (26 females and 24 males, 41 ± 10 years old, whose 4-day dietary records revealed a regular low calcium intake (<=500 mg/day, received an oral calcium load (1 g/day for 7 days. A 24-h urine was obtained before and after load and according to the calciuria under both diets, patients were considered as normocalciuric (NC, N = 15, diet-dependent hypercalciuric (DDHC, N = 9 or diet-independent hypercalciuric (DIHC, N = 26. On regular diet, mean oxaluria was 30 ± 14 mg/24 h for all patients. The 7-day calcium load induced a significant decrease in mean oxaluria compared to the regular diet in NC and DIHC (20 ± 12 vs 26 ± 7 and 27 ± 18 vs 32 ± 15 mg/24 h, respectively, P<0.05 but not in DDHC patients (22 ± 10 vs 23 ± 5 mg/24 h. The lack of an oxalate decrease among DDHC patients after the calcium load might have been due to higher calcium absorption under higher calcium supply, with a consequent lower amount of calcium left in the intestine to bind with oxalate. These data suggest that a long-lasting regular calcium consumption <500 mg was not associated with high oxaluria and that a subpopulation of hypercalciuric patients who presented a higher intestinal calcium absorption (DDHC tended to hyperabsorb oxalate as well, so that oxaluria did not change under different calcium intake.

  15. Transgenic plants with increased calcium stores

    Science.gov (United States)

    Wyatt, Sarah (Inventor); Tsou, Pei-Lan (Inventor); Robertson, Dominique (Inventor); Boss, Wendy (Inventor)

    2004-01-01

    The present invention provides transgenic plants over-expressing a transgene encoding a calcium-binding protein or peptide (CaBP). Preferably, the CaBP is a calcium storage protein and over-expression thereof does not have undue adverse effects on calcium homeostasis or biochemical pathways that are regulated by calcium. In preferred embodiments, the CaBP is calreticulin (CRT) or calsequestrin. In more preferred embodiments, the CaBP is the C-domain of CRT, a fragment of the C-domain, or multimers of the foregoing. In other preferred embodiments, the CaBP is localized to the endoplasmic reticulum by operatively associating the transgene encoding the CaBP with an endoplasmic reticulum localization peptide. Alternatively, the CaBP is targeted to any other sub-cellular compartment that permits the calcium to be stored in a form that is biologically available to the plant. Also provided are methods of producing plants with desirable phenotypic traits by transformation of the plant with a transgene encoding a CaBP. Such phenotypic traits include increased calcium storage, enhanced resistance to calcium-limiting conditions, enhanced growth and viability, increased disease and stress resistance, enhanced flower and fruit production, reduced senescence, and a decreased need for fertilizer production. Further provided are plants with enhanced nutritional value as human food or animal feed.

  16. A Proposed Mechanism for the Thermal Denaturation of a Recombinant Bacillus Halmapalus Alpha-amylase - the Effect of Calcium Ions

    Science.gov (United States)

    Nielsen, Anders D.; Pusey, Marc L.; Fuglsang, Claus C.; Westh, Peter

    2003-01-01

    The thermal stability of a recombinant alpha-amylase from Bacillus halmapalus alpha-amylase (BHA) has been investigated using circular dichroism spectroscopy (CD) and differential scanning calorimetry (DSC). This alpha-amylase is homologous to other Bacillus alpha-amylases where previous crystallographic studies have identified the existence of 3 calcium binding sites in the structure. Denaturation of BHA is irreversible with a Tm of approximately 89 C, and DSC thermograms can be described using a one-step irreversible model. A 5 C increase in T(sub m) in the presence of 10 fold excess CaCl2 was observed. However, a concomitant increase in the tendency to aggregate was also observed. The presence of 30-40 fold excess calcium chelator (EDTA or EGTA) results in a large destabilization of BHA corresponding to about 40 C lower T(sub m), as determined by both CD and DSC. Ten fold excess EGTA reveals complex DSC thermograms corresponding to both reversible and irreversible transitions, which possibly originate from different populations of BHA:calcium complexes. The observations in the present study have, in combination with structural information of homologous alpha-amylases, provided the basis for the proposal of a simple denaturation mechanism of BHA. The proposed mechanism describes the irreversible thermal denaturation of different BHA:calcium complexes and the calcium binding equilibrium involved. Furthermore, the model accounts for a temperature induced reversible structural change associated with calcium binding.

  17. Calcium: A Nutrient Deserving a Special Issue

    Directory of Open Access Journals (Sweden)

    Susan J. Whiting

    2010-10-01

    Full Text Available Interest in calcium has continued since the 1980s when its role in promoting bone growth and retention was established in clinical trials of children and postmenopausal women. The human nutrition functions now attributed to calcium have expanded beyond bone health to include other conditions such as body weight maintenance. While most efforts have been focused on the findings that dietary intakes are low, there are emerging data on safety concerns of excess amounts. This Special Issue on calcium nutrition, spanning the lifecycle from critically ill neonates through to older adults, has been written by some of the leading researchers in this field.

  18. Sorption of UO22+ on calcium carbonate

    International Nuclear Information System (INIS)

    Sorption of uranyl ions on calcium carbonate from aqueous solutions featuring different concentration of calcium nitrate was studied experimentally. It is shown that uranium sorption decreases with calcium concentration growth in solution, irrespective of the ratio of solid phase and solution masses. Specific sorption of uranium per unit of the sorbent surface depends linearly on the ratio of UO22+ and Ca2+ ions activities in solution with proportionality factor (sorption equilibrium constant) 1.71 ± 0.16 mol/m2 at 20 deg C

  19. Calcium signaling in physiology and pathophysiology

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  20. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-Sem; Song, Minsoo, E-mail: minsoosong00@gmail.com; Lee, Eun-Jung; Shin, Ueon Sang, E-mail: usshin12@dankook.ac.kr

    2015-06-01

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H{sub 3}PO{sub 4}/P{sub 2}O{sub 5}/Et{sub 3}PO{sub 4} followed by acid–base reaction with Ca(OAc){sub 2} to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for {sup 1}H, and {sup 31}P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO{sub 4} or CaCl{sub 2} were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min.

  1. Ion beam diagnosis

    International Nuclear Information System (INIS)

    This report is an introduction to ion beam diagnosis. After a short description of the most important ion beam parameters measurements of the beam current by means of Faraday cups, calorimetry, and beam current transformers and measurements of the beam profile by means of viewing screens, profile grids and scanning devices, and residual gas ionization monitors are described. Finally measurements in the transverse and longitudinal phase space are considered. (HSI)

  2. The beam dump tunnels

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    In these images workers are digging the tunnels that will be used to dump the counter-circulating beams. Travelling just a fraction under the speed of light, the beams at the LHC will each carry the energy of an aircraft carrier travelling at 12 knots. In order to dispose of these beams safely, a beam dump is used to extract the beam and diffuse it before it collides with a radiation shielded graphite target.

  3. Modulation of Intracellular Calcium Levels by Calcium Lactate Affects Colon Cancer Cell Motility through Calcium-Dependent Calpain

    OpenAIRE

    Pasupathi Sundaramoorthy; Jae Jun Sim; Yeong-Su Jang; Siddhartha Kumar Mishra; Keun-Yeong Jeong; Poonam Mander; Oh Byung Chul; Won-Sik Shim; Seung Hyun Oh; Ky-Youb Nam; Hwan Mook Kim

    2015-01-01

    Cancer cell motility is a key phenomenon regulating invasion and metastasis. Focal adhesion kinase (FAK) plays a major role in cellular adhesion and metastasis of various cancers. The relationship between dietary supplementation of calcium and colon cancer has been extensively investigated. However, the effect of calcium (Ca2+) supplementation on calpain-FAK-motility is not clearly understood. We sought to identify the mechanism of FAK cleavage through Ca2+ bound lactate (CaLa), its downstrea...

  4. Tx1, from Phoneutria nigriventer spider venom, interacts with dihydropyridine sensitive-calcium channels in GH3 cells

    International Nuclear Information System (INIS)

    The aim of this work was to use the binding assay of tritiated-dihydropyridine and radioiodinated Tx1, isolated from the Phoneutria nigriventer venom, in order to show the presence of Cav1 calcium channels on pituitary tumour cell (GH3). We showed that GH3 cells have specific sites for 125I-Tx1, which are sensitive to nifedipine (∼20%). Reverse competition assay with 3H-PN200-110 (40% inhibition) and electrophysiological data (50% inhibition) suggest that Cav1 calcium channels are target sites for this toxin. To summarize, Tx1 binds to specific sites on GH3 cells and this interaction results in Cav1 calcium channel blockade. 3H-PN200-110 and 125I-Tx1 binding assays proved to be useful tools to show the presence of calcium channels on GH3 cells. (author)

  5. Structures of apicomplexan calcium-dependent protein kinases reveal mechanism of activation by calcium

    Energy Technology Data Exchange (ETDEWEB)

    Wernimont, Amy K; Artz, Jennifer D.; Jr, Patrick Finerty; Lin, Yu-Hui; Amani, Mehrnaz; Allali-Hassani, Abdellah; Senisterra, Guillermo; Vedadi, Masoud; Tempel, Wolfram; Mackenzie, Farrell; Chau, Irene; Lourido, Sebastian; Sibley, L. David; Hui, Raymond (Toronto); (WU-MED)

    2010-09-21

    Calcium-dependent protein kinases (CDPKs) have pivotal roles in the calcium-signaling pathway in plants, ciliates and apicomplexan parasites and comprise a calmodulin-dependent kinase (CaMK)-like kinase domain regulated by a calcium-binding domain in the C terminus. To understand this intramolecular mechanism of activation, we solved the structures of the autoinhibited (apo) and activated (calcium-bound) conformations of CDPKs from the apicomplexan parasites Toxoplasma gondii and Cryptosporidium parvum. In the apo form, the C-terminal CDPK activation domain (CAD) resembles a calmodulin protein with an unexpected long helix in the N terminus that inhibits the kinase domain in the same manner as CaMKII. Calcium binding triggers the reorganization of the CAD into a highly intricate fold, leading to its relocation around the base of the kinase domain to a site remote from the substrate binding site. This large conformational change constitutes a distinct mechanism in calcium signal-transduction pathways.

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

    Science.gov (United States)

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

    2008-06-01

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

  7. Technology obtaining of nitrogen fertilizer from the calcium is containing waste of production of calcium saltpetre

    OpenAIRE

    Власян, Світлана Варужанівна; Шестозуб, Анатолій Борисович; Волошин, Микола Дмитрович

    2013-01-01

    The new technology of obtaining nitrogen fertilizer from calcium-containing sludge of calcium saltpeter production is considered in the paper. The main objective of the research is the development of processing technology of sludge of calcium saltpeter production into alkaline nitrogen fertilizer, analysis of the composition of initial material and finished product, testing of fertilizer by means of vegeta­tive studies and determination of expenditure of drying agent that is exhaust gases of ...

  8. In vivo Calcium Imaging of Evoked Calcium Waves in the Embryonic Cortex

    OpenAIRE

    Yuryev, Mikhail; Pellegrino, Christophe; Jokinen, Ville; Andriichuk, Liliia; Khirug, Stanislav; Khiroug, Leonard; Rivera, Claudio

    2016-01-01

    The dynamics of intracellular calcium fluxes are instrumental in the proliferation, differentiation, and migration of neuronal cells. Knowledge thus far of the relationship between these calcium changes and physiological processes in the developing brain has derived principally from ex vivo and in vitro experiments. Here, we present a new method to image intracellular calcium flux in the cerebral cortex of live rodent embryos, whilst attached to the dam through the umbilical cord. Using this ...

  9. Relationship between sealing ability of Activ GP and Gutta Flow and methods of calcium hydroxide removal

    Directory of Open Access Journals (Sweden)

    Vineeta Nikhil

    2012-01-01

    Full Text Available Aim: To evaluate the effect of method of calcium hydroxide intracanal dressing removal, on sealing ability of Gutta Flow and Activ GP. Materials and Methods: Seventy extracted mandibular premolars were sectioned at CEJ and canals were prepared with profile 4% rotary file till #40. Canals were filled with calcium hydroxide, coronally sealed with Cavit G and stored at 37°C. After 7 days, samples were divided on the basis of calcium hydroxide removal method (Master apical file, Navi Tip FX, and F File and obturating material (Activ GP and Gutta Flow. Three coats of nail polish were applied except 2 mm around apical foramen and samples were immersed in India ink dye, sectioned, and observed under stereomicroscope for microleakage. Results: The results were statistically analyzed with one way ANOVA-F with Tukey HSD test with the null hypothesis set as 5%. Conclusions: The seal of the canal system was adversely impacted by residual calcium hydroxide when Activ GP and Gutta Flow were used as obturating material and the sealing ability of Activ GP and Gutta Flow was better when MAF was used for removal of calcium hydroxide than F file or Navi tip FX.

  10. 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...

  11. Assessment of calcium content of lumbarspine by computed tomography

    International Nuclear Information System (INIS)

    Assessment of calcium content of lumbar spine by computed tomography was performed on 76 patients without bone disease and 15 patients with chronic renal failure. Calcium content of medulla and cortex was calculated by CT number. Relationship between calcium content of medulla, cortex and age was discussed. The necessity of midline scan of lumbar spine to obtain the accurate calcium was also stressed. (author)

  12. 21 CFR 172.120 - Calcium disodium EDTA.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium disodium EDTA. 172.120 Section 172.120 Food... Food Preservatives § 172.120 Calcium disodium EDTA. The food additive calcium disodium EDTA (calcium... 100 Promote color retention. 1 By weight of egg yolk portion. (2) With disodium EDTA...

  13. Selective extraction of calcium on tri-n-butyl phosphate plasticized selective extraction of calcium on tri-n-butyl phosphate plasticized polyurethane foam for its spectrophotometric determination in glass and ceramics.

    Science.gov (United States)

    Mondal, Jayanta K; Kundu, Dipali

    2005-12-01

    The present paper describes the application of a solid phase extraction system in order to separate traces of calcium from glass and ceramics for its spectrophotometric determination. The method is based on the extraction of calcium from sodium hydroxide solution by tri-n-butyl phosphate (TBP) loaded polyurethane foam (PUF), followed by its elution in hydrochloric acid. The spectrophotometric measurement of the absorbance of calcium complex with calconcarboxylic acid (2-hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3-naphthoic acid) takes place at pH 12. The following parameters were studied: effects of sodium hydroxide concentration and temperature on the extraction of calcium, time of equilibration for quantitative calcium extraction, effect of TBP concentration, effect of hydrochloric acid concentration for quantitative elution of calcium from PUF, effect of pH and concentration of calconcarboxylic acid for quantitative formation of the complex with calcium, effect of acetone on the stability of calcium-calconcarboxylic acid complex and influence of diverse ions on calcium sorption by TBP-loaded PUF. The results show that calcium traces can be separated onto TBP-loaded PUF from 0.25 mol L(-1) NaOH at 30 +/- 5 degrees C within 30 min. PUF was loaded with TBP in CCl4 (40% v/v). Elution of calcium was done in 1.0 mol l(-1) HCl. The calcium formed a complex with calconcarboxylic acid at pH 12 and absorbance was measured at 560 nm in acetone-water medium. Molar absorptivity was found to be 1.082 x 10(4) l mol(-1) cm(-1). The method obeys Beer's law from 0.10 to 5.0 microg ml(-1) Ca. The validity of the method was established by its successful application in NIST standard reference materials. The method proposed was applied to determine calcium in glass and ceramic materials. The results of the proposed method are comparable with the results of ICP-AES analysis and they are found to be in good agreement. PMID:16379392

  14. Geometrically focused neutral beam accelerators

    International Nuclear Information System (INIS)

    A more reliable 40 kV, 65 A power supply drain at 0.4 A/cm2, neutral-beam accelerator was developed for the Tandem Mirror Experiment (TMX). Multiple slotted aperture grids of 60% transparency are fabricated from refractory metal wires mounted to form a spherical surface. This geometrically focuses the beam by aiming individual beamlets at the center of curvature of the spherical grid (r = 3.2 m). We attain greater reliability and faster conditioning with geometrical focusing than with the previous technique of electrostatically steering beamlets to a common point. Electrostatic steering, accomplished by offsetting grid wires, is satisfactory if the offset of a beamlet is much less than the distance from the beamlet to the grids. It was found that Pierce Angle entrance grids performed better if sharper edged. A redesigned accelerator grid support structure reduced the number of ceramic-to-metal vacuum joints, and eliminated O rings between precisely aligned parts. The suppressor grid feedthrough is required to withstand a maximum voltage of 15 kV occurring during breakdown, greatly exceeding the operating voltage of 1.5 kV. Convenient fabrication and assembly techniques have been developed. Assembly of accelerators and plasma sources in a clean room appears to reduce the conditioning time. Following the successful testing of the prototype, eight 40 kV accelerators were built for TMX. Furthermore, ten 20 kV versions were built that are modifiable to 40 kV by exchanging the entrance grid

  15. Astrocyte calcium signaling: the third wave.

    Science.gov (United States)

    Bazargani, Narges; Attwell, David

    2016-01-27

    The discovery that transient elevations of calcium concentration occur in astrocytes, and release 'gliotransmitters' which act on neurons and vascular smooth muscle, led to the idea that astrocytes are powerful regulators of neuronal spiking, synaptic plasticity and brain blood flow. These findings were challenged by a second wave of reports that astrocyte calcium transients did not mediate functions attributed to gliotransmitters and were too slow to generate blood flow increases. Remarkably, the tide has now turned again: the most important calcium transients occur in fine astrocyte processes not resolved in earlier studies, and new mechanisms have been discovered by which astrocyte [Ca(2+)]i is raised and exerts its effects. Here we review how this third wave of discoveries has changed our understanding of astrocyte calcium signaling and its consequences for neuronal function. PMID:26814587

  16. 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)

  17. Modeling and analysis of calcium bromide hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-05-15

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

  18. Discrete stochastic modeling of calcium channel dynamics

    CERN Document Server

    Baer, M E; Levine, H; Tsimring, L S; Baer, Markus; Falcke, Martin; Levine, Herbert; Tsimring, Lev S.

    1999-01-01

    We propose a simple discrete stochastic model for calcium dynamics in living cells. Specifically, the calcium concentration distribution is assumed to give rise to a set of probabilities for the opening/closing of channels which release calcium thereby changing those probabilities. We study this model in one dimension, analytically in the mean-field limit of large number of channels per site N, and numerically for small N. As the number of channels per site is increased, the transition from a non-propagating region of activity to a propagating one changes in nature from one described by directed percolation to that of deterministic depinning in a spatially discrete system. Also, for a small number of channels a propagating calcium wave can leave behind a novel fluctuation-driven state, in a parameter range where the limiting deterministic model exhibits only single pulse propagation.

  19. Discrete Stochastic Modeling of Calcium Channel Dynamics

    International Nuclear Information System (INIS)

    We propose a discrete stochastic model for calcium dynamics in living cells. A set of probabilities for the opening/closing of calcium channels is assumed to depend on the calcium concentration. We study this model in one dimension, analytically in the limit of a large number of channels per site N , and numerically for small N . As the number of channels per site is increased, the transition from a nonpropagating region of activity to a propagating one changes from one described by directed percolation to that of deterministic depinning in a spatially discrete system. Also, for a small number of channels a propagating calcium wave can leave behind a novel fluctuation-driven state. (c) 2000 The American Physical Society

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

    International Nuclear Information System (INIS)

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

  1. Characterization of Calcium Compounds in Opuntia ficus indica as a Source of Calcium for Human Diet

    OpenAIRE

    Isela Rojas-Molina; Elsa Gutiérrez-Cortez; Moustapha Bah; Alejandra Rojas-Molina; César Ibarra-Alvarado; Eric Rivera-Muñoz; Alicia del Real; Ma. de los Angeles Aguilera-Barreiro

    2015-01-01

    Analyses of calcium compounds in cladodes, soluble dietary fiber (SDF), and insoluble dietary fiber (IDF) of Opuntia ficus indica are reported. The characterization of calcium compounds was performed by using Scanning Electron Microscopy, Energy Dispersive Spectrometry, X-ray diffraction, and infrared spectroscopy. Atomic Absorption Spectroscopy and titrimetric methods were used for quantification of total calcium and calcium compounds. Whewellite (CaC2O4·H2O), weddellite (CaC2O4·(H2O)2.375),...

  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. Calcium entry into guinea-pig jejunum cells after calcium stores depletion.

    Science.gov (United States)

    Pacaud, P; Bolton, T B

    1991-01-01

    1) Membrane currents were recorded under voltage-clamp from cells using patch-clamp pipettes. Cells were dialysed with potassium-free caesium solution to block any Ca-activated K-current. The pipette solution contained Indo-1 and the ratio of the emissions from this dye at 480 and 405 nm was used to estimate the free calcium concentration in the cell. 2) Carbachol applied to the cell evoked at -50 mV an initial increase in the intracellular calcium concentration (Cai) followed by a smaller sustained rise (plateau); the changes in inward cationic current (ICarb) closely followed changes in Cai. Calcium entry blockers did not affect these responses. 3) The initial peak in Cai produced by carbachol was due to calcium store release: it was present in calcium-free solution, and unchanged at +50 mV, but it was abolished by prior application of caffeine (10 mM) to the cell or by inclusion of heparin (which blocks D-myoinositol 1,4,5-trisphosphate receptors) in the pipette. 4) The sustained rise (plateau) in Cai produced by carbachol was due to the entry of calcium into the cell down its electrochemical gradient as it was affected by changing the cell membrane potential or the calcium concentration in the bathing solution. As the sustained rise in Cai produced by caffeine had similar properties it was suggested that depletion of calcium stores can evoke an increased calcium entry into the cell through some pathway. PMID:1665265

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

  5. Effect of albumin and free calcium concentrations on calcium binding in vitro.

    OpenAIRE

    Besarab, A; DeGuzman, A; Swanson, J W

    1981-01-01

    In vivo equilibrium dialysis studies were performed to define further the characteristics of calcium binding to bovine albumin. The concentration range for albumin (1 to 9 g/dl) as well as ultrafilterable calcium (0.5 to 2.5 mM) studied encompassed those that might be ordinarily encountered in most clinical situations. Major differences in the regressions of total calcium on ultrafilterable calcium occurred at albumin concentrations of 1, 2, and 9 g/dl but only small differences at albumin co...

  6. Study of calcium chloride and calcium nitrate purification on inorganic sorbents

    International Nuclear Information System (INIS)

    Purification of calcium chloride and calcium nitrate from iron, chromium, manganese and cobalt impurities by sorption on some inorganic collectors are considered in this article. Study was conducted by means of radioactive-tracer technique at concurrent use of several γ-radioactive isotopes. As a collectors were used hydrated aluminium and zirconium oxides. Dependence of effectiveness of precipitation by collectors on ph-value of medium, quantity of collector, nature and concentration of components is studied. Optimal parameters of purification of calcium chloride and calcium nitrate are defined.

  7. 21 CFR 201.70 - Calcium labeling.

    Science.gov (United States)

    2010-04-01

    ... product is more than 3.2 grams: “Ask a doctor before use if you have 1 kidney stones a calcium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201.72(c) may be combined, if applicable, provided the ingredients are listed in alphabetical order, e.g., a calcium or sodium restricted diet. 1...

  8. 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

  9. Oral calcium supplementation in peripartum dairy cows.

    Science.gov (United States)

    Oetzel, Garrett R

    2013-07-01

    Hypocalcemia in dairy cattle around parturition can be manifest as clinical milk fever or subclinical hypocalcemia. Subclinical hypocalcemia has the greatest economic effect because it affects a much higher proportion of cows. Oral calcium supplements are used to mitigate the effects of both forms of hypocalcemia. Oral calcium supplements are appropriate for cows displaying early clinical signs of hypocalcemia and prophylactically to lessen the negative impacts of hypocalcemia. PMID:23809900

  10. DETERMINATION OF CALCIUM CONTENT IN DIETARY SUPPLEMENTS

    OpenAIRE

    Marjanović-Balaban, Željka R.; Antunović, Vesna R.; Jelić, Dijana R.; Živković, Tanja M.

    2015-01-01

    Calcium is a macro element that is very important for the human body: its content and circulation in the body is large, it serves as the electrolyte, it has a building role and participates in the process of metabolism. The European Union, the World Health Organization (WHO) and the Ministry of Food and Drug (Food and Drug Administration, FDA) gave the RDA (Recommended Dietary Allowances,) for this macro element. The absorption and bioavailability of the calcium may vary depending on a number...

  11. Rickets induced by calcium or phosphate depletion.

    OpenAIRE

    Abugassa, S.; Svensson, O.

    1990-01-01

    We studied the effects of calciopenia and phosphopenia on longitudinal growth, skeletal mineralization, and development of rickets in young Sprague-Dawley rats. At an age of 21 days, two experimental groups were given diets containing 0.02% calcium or 0.02% phosphorus; otherwise the diets were nutritionally adequate. After 7, 14, and 21 days, five animals from each group were randomly chosen. The animals were anaesthetized and blood samples were drawn for analysis of calcium, phosphorus, and ...

  12. Gel time of calcium acrylate grouting material.

    Science.gov (United States)

    Han, Tong-Chun

    2004-08-01

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

  13. Understanding calcium dynamics experiments and theory

    CERN Document Server

    Malchow, Dieter

    2003-01-01

    Intracellular Calcium is an important messenger in living cells. Calcium dynamics display complex temporal and spatial structures created by the concentration patterns which are characteristic for a nonlinear system operating far from thermodynamic equilibrium. Written as a set of tutorial reviews on both experimental facts and theoretical modelling, this volume is intended as an introduction and modern reference in the field for graduate students and researchers in biophysics, biochemistry and applied mathematics.

  14. Intense positron beams: linacs

    International Nuclear Information System (INIS)

    Beams of monoenergetic positrons with energies of a few eV to many keV have been used in experiments in atomic physics, solid-state physics and materials science. The production of positron beams from a new source, an electron linac, is described. Intense, pulsed beams of low-energy positrons were produced by a high-energy beam from an electron linac. The production efficiency, moderator geometry, beam spot size and other positron beam parameters were determined for electrons with energies from 60 to 120 MeV. Low-energy positron beams produced with a high-energy electron linac can be of much higher intensity than those beams currently derived from radioactive sources. These higher intensity beams will make possible positron experiments previously infeasible. 10 references, 1 figure

  15. A theory of Plasma Membrane Calcium Pump stimulation and activity

    CERN Document Server

    Graupner, M; Meyer-Hermann, M; Erler, Frido; Graupner, Michael; Meyer-Hermann, Michael

    2003-01-01

    The ATP-driven Plasma Membrane Calcium (PMCA) pump is characterized by a high affinity to calcium and a low transport rate compared to other transmembrane calcium transport proteins. It plays a crucial role for calcium extrusion from cells. Calmodulin is an intracellular calcium buffering protein which is capable in its Calcium-liganded form to stimulate the PMCA pump by increasing both, the affinity to calcium and the maximum calcium transport rate. We introduce a new model of this stimulation process and deduce analytical expressions for experimental observables in order to determine the model parameter on the basis of specific experiments. Furthermore a model for the pumping activity is developed. In contrast to the biological process we have to describe the pumping rate behavior by assuming a ATP:Calcium stoichiometry of 2 in order to reproduce experimental data. The conjunction of the description of calcium pumping and the stimulation model fully and correctly simulates PMCA pump function. Therewith the ...

  16. Beam instability studies at the APS

    International Nuclear Information System (INIS)

    The Argonne Advanced Photon Source, APS (Fig. 1), is a 7-GeV positron storage ring with a circumference of 1104 m. It has a ''third generation, DBA or Chasman-Green'' lattice composed of 40 sectors each having a ∼6 m long zero-dispersion straight-section for accommodating insertion devices. Neighboring straight-sections are connected by a 360 degrees/40 = 9 degrees double-bend-achromatic bending section designed to produce the smallest emittance attainable with reasonable component parameter values and dynamic apertures. Thus, it is a very strongly focusing lattice with vx = 35.22 and vy = 14.30. The beam chamber of the storage ring including all rf, vacuum and photon beam components is designed to ensure that a beam current > 100 mA can be stably stored. We expect that the maximum stable beam current could be as high as 300 mA. This paper will give some details of the studies and computations to ensure the stability of such a beam. The discussions will be organized in the following three parts: Coupled-bunch instability caused by the higher-order modes (HOMs) of the rf cavities; Single-bunch instability due to the resistive wall impedance; and Single-bunch instability due to broadband impedances arising from beam chamber irregularities

  17. Calcium and available phosphorus levels for laying hens in second production cycle

    Directory of Open Access Journals (Sweden)

    K Pelicia

    2009-03-01

    Full Text Available This experiment studied the effect of four calcium (3.0, 3.5, 4.0, and 4.5% and four available phosphorus levels (0.25, 0.30, 0.35, and 0.40% in the diet of semi-heavy commercial layers after molting. Hisex Brown® layers between 90 and 108 weeks of age were distributed in a completely randomized experimental design with a 4x4 factorial arrangement with 16 treatments of five replicates of eight birds each. mortality, egg production, feed intake, egg mass, average egg weight, calcium and phosphorus intake, feed conversion ratio (per dozen eggs and per kg eggs, eggshell percentage and thickness, eggshell strength, eggshell weight per surface area (ESWSA, yolk percentage and color, albumen percentage, albumen and yolk heights, and blood and excreta calcium and phosphorus concentrations. There was no interaction (P>0.05 between dietary Ca and avP for any of the studied parameters. There were linear increases in Ca intake (P0.05 by dietary Ca and avP levels. The diet containing 4.5% calcium improved feed conversion ratio per dozen eggs and eggshell quality. The lowest avP level fed (0.25% is sufficient to maintain the performance and the egg quality of semi-heavy commercial layers after molting.

  18. The effect of calcium and phosphorus supplementation on metabolic bone disorders in premature infants

    International Nuclear Information System (INIS)

    Objective: To determine the impact of calcium and phosphorus on radiological and biochemical characteristics of osteopenia in premature infants. Methods: The randomised clinical trial study was conducted at Valie-e-Asr Hospital of Zanjan city, Iran, from December 2010 to June 2011. It involved monitoring 40 premature neonates over a period of six months. The babies, who were fed with breast milk and 400 units of vitamin D daily, were randomly divided into two equal groups. One group received supplement of calcium and phosphorus. Serum calcium, phosphorus and alkaline phosphatase levels as well as growth parameters (including weight, height, and head circumference) were measured every two weeks. At the end of the study, wrist X-ray was done for evaluation of osteopenia. Data was analysed using SPSS 16. Results: Radiological changes, characteristic of osteopenia, were found in 8(40%) cases and 13(65%) controls (p<0.113). The mean of weight, length and head circumference increased significantly from second to sixth week during follow-up (p<0.0001). Phosphorus and alkaline phosphatase activity decreased significantly from second to sixth week of follow-up (p<0.02, p<0.01 respectively). However, repeated measurement analyses did not show significant effect of intervention in biochemical and growth parameters in the trial group. Conclusion: The study didn't show significant effect of calcium and phosphorus on prevention of osteopenia and improvement of growth. Further studies of longer duration and with different doses of supplement are recommended. (author)

  19. Two cavity autoacceleration of an intense relativistic electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, P.D.; Lockner, T.R.

    1985-01-01

    Two autoacceleration cavities have been used to accelerate an 11-kA electron beam from 2 MeV to approx. =2.8 MeV. The two 40-..cap omega.. cavities each accelerated the beam by approx. =400 kV with no observable interaction between the two cavities over several cavity transmit times. 6 figs.

  20. Two cavity autoacceleration of an intense relativistic electron beam

    International Nuclear Information System (INIS)

    Two autoacceleration cavities have been used to accelerate an 11-kA electron beam from 2 MeV to approx. =2.8 MeV. The two 40-Ω cavities each accelerated the beam by approx. =400 kV with no observable interaction between the two cavities over several cavity transmit times. 6 figs

  1. A calcium-induced calcium release mechanism mediated by calsequestrin.

    Science.gov (United States)

    Lee, Young-Seon; Keener, James P

    2008-08-21

    Calcium (Ca(2+))-induced Ca(2+) release (CICR) is widely accepted as the principal mechanism linking electrical excitation and mechanical contraction in cardiac cells. The CICR mechanism has been understood mainly based on binding of cytosolic Ca(2+) with ryanodine receptors (RyRs) and inducing Ca(2+) release from the sarcoplasmic reticulum (SR). However, recent experiments suggest that SR lumenal Ca(2+) may also participate in regulating RyR gating through calsequestrin (CSQ), the SR lumenal Ca(2+) buffer. We investigate how SR Ca(2+) release via RyR is regulated by Ca(2+) and calsequestrin (CSQ). First, a mathematical model of RyR kinetics is derived based on experimental evidence. We assume that the RyR has three binding sites, two cytosolic sites for Ca(2+) activation and inactivation, and one SR lumenal site for CSQ binding. The open probability (P(o)) of the RyR is found by simulation under controlled cytosolic and SR lumenal Ca(2+). Both peak and steady-state P(o) effectively increase as SR lumenal Ca(2+) increases. Second, we incorporate the RyR model into a CICR model that has both a diadic space and the junctional SR (jSR). At low jSR Ca(2+) loads, CSQs are more likely to bind with the RyR and act to inhibit jSR Ca(2+) release, while at high SR loads CSQs are more likely to detach from the RyR, thereby increasing jSR Ca(2+) release. Furthermore, this CICR model produces a nonlinear relationship between fractional jSR Ca(2+) release and jSR load. These findings agree with experimental observations in lipid bilayers and cardiac myocytes. PMID:18538346

  2. Contribution of calcium oxalate to soil-exchangeable calcium

    Science.gov (United States)

    Dauer, Jenny M.; Perakis, Steven S.

    2013-01-01

    Acid deposition and repeated biomass harvest have decreased soil calcium (Ca) availability in many temperate forests worldwide, yet existing methods for assessing available soil Ca do not fully characterize soil Ca forms. To account for discrepancies in ecosystem Ca budgets, it has been hypothesized that the highly insoluble biomineral Ca oxalate might represent an additional soil Ca pool that is not detected in standard measures of soil-exchangeable Ca. We asked whether several standard method extractants for soil-exchangeable Ca could also access Ca held in Ca oxalate crystals using spike recovery tests in both pure solutions and soil extractions. In solutions of the extractants ammonium chloride, ammonium acetate, and barium chloride, we observed 2% to 104% dissolution of Ca oxalate crystals, with dissolution increasing with both solution molarity and ionic potential of cation extractant. In spike recovery tests using a low-Ca soil, we estimate that 1 M ammonium acetate extraction dissolved sufficient Ca oxalate to contribute an additional 52% to standard measurements of soil-exchangeable Ca. However, in a high-Ca soil, the amount of Ca oxalate spike that would dissolve in 1 M ammonium acetate extraction was difficult to detect against the large pool of exchangeable Ca. We conclude that Ca oxalate can contribute substantially to standard estimates of soil-exchangeable Ca in acid forest soils with low soil-exchangeable Ca. Consequently, measures of exchangeable Ca are unlikely to fully resolve discrepancies in ecosystem Ca mass balance unless the contribution of Ca oxalate to exchangeable Ca is also assessed.

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

    Science.gov (United States)

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

    2011-12-01

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

  4. Membrane associated complexes in calcium dynamics modelling

    International Nuclear Information System (INIS)

    Mitochondria not only govern energy production, but are also involved in crucial cellular signalling processes. They are one of the most important organelles determining the Ca2+ regulatory pathway in the cell. Several mathematical models explaining these mechanisms were constructed, but only few of them describe interplay between calcium concentrations in endoplasmic reticulum (ER), cytoplasm and mitochondria. Experiments measuring calcium concentrations in mitochondria and ER suggested the existence of cytosolic microdomains with locally elevated calcium concentration in the nearest vicinity of the outer mitochondrial membrane. These intermediate physical connections between ER and mitochondria are called MAM (mitochondria-associated ER membrane) complexes. We propose a model with a direct calcium flow from ER to mitochondria, which may be justified by the existence of MAMs, and perform detailed numerical analysis of the effect of this flow on the type and shape of calcium oscillations. The model is partially based on the Marhl et al model. We have numerically found that the stable oscillations exist for a considerable set of parameter values. However, for some parameter sets the oscillations disappear and the trajectories of the model tend to a steady state with very high calcium level in mitochondria. This can be interpreted as an early step in an apoptotic pathway. (paper)

  5. Applications of power beaming from space-based nuclear power stations. [Laser beaming to airplanes; microwave beaming to ground

    Energy Technology Data Exchange (ETDEWEB)

    Powell, J.R.; Botts, T.E.; Hertzberg, A.

    1981-01-01

    Power beaming from space-based reactor systems is examined using an advanced compact, lightweight Rotating Bed Reactor (RBR). Closed Brayton power conversion efficiencies in the range of 30 to 40% can be achieved with turbines, with reactor exit temperatures on the order of 2000/sup 0/K and a liquid drop radiator to reject heat at temperatures of approx. 500/sup 0/K. Higher RBR coolant temperatures (up to approx. 3000/sup 0/K) are possible, but gains in power conversion efficiency are minimal, due to lower expander efficiency (e.g., a MHD generator). Two power beaming applications are examined - laser beaming to airplanes and microwave beaming to fixed ground receivers. Use of the RBR greatly reduces system weight and cost, as compared to solar power sources. Payback times are a few years at present prices for power and airplane fuel.

  6. The effect of dimethylsulfoxide on the calcium paradox.

    OpenAIRE

    Ruigrok, T. J.; Moes, D.; Slade, A.M.; Nayler, W. G.

    1981-01-01

    Reperfusion of isolated rat hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). Experiments were undertaken to study the effect of dimethylsulfoxide (DMSO) on the occurrence of the calcium paradox in rat heart muscle. DMSO (1.4 mol/l) was added to the calcium-free or the reperfusion medium. Cell damage was quantitated in terms of creatine kinase (CK) release, cardiac electrogram (CEG) changes, and ultras...

  7. Factors to consider in the selection of a calcium supplement.

    OpenAIRE

    Shangraw, R F

    1989-01-01

    Calcium supplements are widely used, yet many questions remain as to the absorption of various calcium salts. Because the solubility of many calcium salts is dependent upon pH, the type of salt used, the condition of the patient, and the time of administration should be considered. Studies show that many calcium supplements on the market today do not meet standards of quality established in the "U.S. Pharmacopeia" (USP). Consumers must be discerning about the products they purchase. Calcium s...

  8. The spatial pattern of atrial cardiomyocyte calcium signalling modulates contraction

    OpenAIRE

    Mackenzie, L; Roderick, H Llewelyn; Berridge, MJ; Conway, SJ; Bootman, MD

    2004-01-01

    We examined the regulation of calcium signalling in atrial cardiomyocytes during excitation-contraction coupling, and how changes in the distribution of calcium impacts on contractility. Under control conditions, calcium transients originated in subsarcolemmal locations and showed local regeneration through activation of calcium-induced calcium release from ryanodine receptors. Despite functional ryanodine receptors being expressed at regular (~2 μm) intervals throughout atrial myocytes, the ...

  9. Increased absolute calcium binding to albumin in hypoalbuminaemia.

    OpenAIRE

    Besarab, A; Caro, J F

    1981-01-01

    The amount of calcium bound to protein was measured in 30 patients with differing diseases and varying degrees of hypoalbuminaemia. Total serum calcium increased directly with both serum albumin and ultrafilterable calcium concentrations. The estimated amount of calcium bound per gram of albumin varied inversely with the albumin concentration, decreasing from 2.1 to 1.0 mg calcium/g albumin as albumin concentration increased from 1.7 to 3.1 g/dl. Circulating parathyroid hormone (PTH) concentr...

  10. Effect of calcium on adsorptive removal of As(III) and As(V) by iron oxide-based adsorbents

    KAUST Repository

    Uwamariya, V.

    2014-06-25

    The effects of calcium on the equilibrium adsorption capacity of As(III) and As(V) onto iron oxide-coated sand (IOCS) and granular ferric hydroxide (GFH) were investigated through batch experiments, rapid small-scale column tests (RSSCT) and kinetics modelling. Batch experiments showed that at calcium concentrations≤20 mg/L, high As(III) and As(V) removal efficiencies by IOCS and GFH are achieved at pH 6. An increase of the calcium concentration to 40 and 80 mg/L reversed this trend, giving higher removal efficiencies at higher pH (8). The adsorption capacities of IOCS and GFH at an equilibrium arsenic concentration of 10 g/L were found to be between 2.0 and 3.1 mg/g for synthetic water without calcium and between 2.8 and 5.3 mg/g when 80 mg/L of calcium was present at the studied pH values. After 10 hours of filter run in RSSCT, approximately 1000 empty bed volumes, the ratios of C/Co for As(V) were 26% and 18% for calcium-free model water; and only 1% and 0.2% after addition of 80 mg/L of Ca for filter columns with IOCS and GFH, respectively. The adsorption of As(III) and As(V) onto GFH follows a second-order reaction, with and without addition of calcium. The adsorption of As(III) and As(V) onto IOCS follows a first-order reaction without calcium addition, and moves to the second-reaction-order kinetics when calcium is added. Based on the intraparticle diffusion model, the main controlling mechanism for As(III) adsorption is intraparticle diffusion, while surface diffusion contributes greatly to the adsorption of As(V).

  11. Red Liriope platyphylla stimulated the insulin secretion through the regulation of calcium concentration in rat insulinoma cells and animal models.

    Science.gov (United States)

    Lee, Hye-Ryun; Kim, Ji-Eun; Lee, Young-Ju; Kwak, Moon-Hwa; Im, Dong-Soon; Hwang, Dae-Youn

    2013-06-01

    The aim of this study was to investigate the effects of Red L. platyphylla (RLP) on calcium and glucose levels during insulin secretion. To achieve this, alteration of insulin and calcium concentrations was measured in rat insulinoma-1 (INS-1) cells and animal models in response to RLP treatment. In INS-1 cells, maximum secretion of insulin was detected upon treatment with 200 µg/mL of RLP for 20 min. Nifedipine, an L-type calcium channel blocker, effectively inhibited insulin secretion from INS-1 cells. Regarding calcium levels, the maximum concentration of intracellular calcium in INS-1 cells was obtained by treatment with 100 µg/mL of RLP, whereas this level was reduced under conditions of 200 µg/mL of RLP. Further, RLP-treated INS-1 cells showed a higher level of intracellular calcium than that of L. platyphylla (LP), Korea White Ginseng (KWG), or Korea Red Ginseng (KRG)-treated cells. This RLP-induced increase in intracellular calcium was abrogated but not completely abolished upon treatment with 40 µM nifedipine in a dose-dependent manner. Furthermore, the insulin level was dramatically elevated upon co-treatment with high concentrations of glucose and RLP, whereas it was maintained at a low level in response to glucose and RLP co-treatment at low concentrations. In an animal experiment, the serum concentration of calcium increased or decreased upon RLP treatment according to glucose level compared to vehicle treatment. Therefore, these results suggest that insulin secretion induced by RLP treatment may be tightly correlated with calcium regulation, which suggests RLP is an excellent candidate for diabetes treatment. PMID:23825481

  12. Effect of combining different calcium concentration dialysate on calcium balance in peritoneal dialysis patients

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hui-ping; WU Bei; LU Li-xia; QIAO Jie; WU Xiang-lan; WANG Mei

    2012-01-01

    Background Calcium and phosphorus metabolic disturbance are common in dialysis patients and associated with increased morbidity and mortality.Therefore,maintaining the balance of calcium and phosphate metabolism and suitable intact parathyroid hormone(iPTH)level has become the focus of attention.We investigated the effects of different peritoneal dialysate calcium concentrations on calcium phosphate metabolism and iPTH in continuous ambulatory peritoneal dialysis(CAPD)patients.Methods Forty stable CAPD patients with normal serum calcium were followed for six months of treatment with 1.25 mmol/L calcium dialysate(DCa1.25,PD4,22 patients)or a combination of 1.75 mmol/L calcium dialysate(DCa1.75,PD2)and PD4(18 patients)twice a day respectively.Total serum calcium(after albumin correction),serum phosphorus,iPTH,alkaline phosphatase(ALP)and blood pressure were recorded before and 1,3 and 6 months after treatment commenced.Results No significant difference was found in baseline serum calcium,phosphorus between the two patient groups,but the levels of iPTH were significantly different.No significant changes were found in the dosage of calcium carbonate and active vitamin D during 6 months.In the PD4 group,serum calcium level at the 1st,3rd,6th months were significantly lower than the baseline(P<0.05).There was no significant difference in serum phosphorus after 6 months treatment.iPTH was significantly higher(P<0.001)at the 1st,3rd,and 6th months compared with the baseline.No differences were seen in ALP and blood pressure.In the PD4+PD2 group,no significant changes in serum calcium,phosphorus,iPTH,ALP and BP during the 6-month follow-up period.Conclusions Treatment with 1.25 mmol/L calcium dialysate for six months can decrease serum calcium,increase iPTH,without change in serum phosphorus,ALP,and BP.The combining of PD4 and PD2 can stabilize the serum calcium and avoid fluctuations in iPTH levels.

  13. Small field dosimetry and analysis of flattening filter free beams in true beam system

    Directory of Open Access Journals (Sweden)

    K R Muralidhar

    2015-01-01

    Full Text Available Aim of Study: The purpose of this study was to report the dosimetric characteristics of the small fields in flattening filter free (FFF beams (output measurements, profile analysis, surface dose and consistency generated by medical linear accelerator and its variation with respect to flattened beams (FB. Materials and Methods: Surface doses were obtained for field sizes 1 × 1-40 × 40 cm 2 . Field width and penumbra were analyzed for field sizes 1 × 1-40 × 40 cm 2 . To take output factors for small fields, diode and micro chamber were used and data was taken at a source-to-surface distance (SSD and extended SSD. Consistency checked for the dosimetric data for 1 year. Results: Surface doses were higher in FFF compared with FB up to 20 × 20 cm 2 field size. Measured field sizes were slightly lesser in FFF and penumbra values were increased with respect to field size in both FB and FFF. For small fields, diode values have shown more promising results than micro chamber. Small field output measurements at nominal SSD and extended SSD were well in agreement with each other. FFF beams showed good data consistency in 1 year duration. Conclusion: Small field dosimetry, surface dose, profile analysis and consistency of FFF beams in FFF photon beams were derived and data shown good consistency during 1 year duration.

  14. Increased calcium absorption from synthetic stable amorphous calcium carbonate: Double-blind randomized crossover clinical trial in post-menopausal women

    Science.gov (United States)

    Calcium supplementation is a widely recognized strategy for achieving adequate calcium intake. We designed this blinded, randomized, crossover interventional trial to compare the bioavailability of a new stable synthetic amorphous calcium carbonate (ACC) with that of crystalline calcium carbonate (C...

  15. Beam Dynamics and Beam Losses - Circular Machines

    CERN Document Server

    Kain, V

    2016-01-01

    A basic introduction to transverse and longitudinal beam dynamics as well as the most relevant beam loss mechanisms in circular machines will be presented in this lecture. This lecture is intended for physicists and engineers with little or no knowledge of this subject.

  16. Electron beam instabilities in gyrotron beam tunnels

    International Nuclear Information System (INIS)

    Electron beam instabilities occurring in a gyrotron electron beam can induce an energy spread which might significantly deteriorate the gyrotron efficiency. Three types of instabilities are considered to explain the important discrepancy found between the theoretical and experimental efficiency in the case of quasi-optical gyrotrons (QOG): the electron cyclotron maser instability, the Bernstein instability and the Langmuir instability. The low magnetic field gradient in drift tubes of QOG makes that the electron cyclotron maser instability can develop in the drift tube at very low electron beam currents. Experimental measurements show that with a proper choice of absorbing structures in the beam tunnel, this instability can be suppressed. At high beam currents, the electrostatic Bernstein instability can induce a significant energy spread at the entrance of the interaction region. The induced energy spread scales approximately linearly with the electron beam density and for QOG one observes that the beam density is significantly higher than the beam density of an equivalent cylindrical cavity gyrotron. (author) figs., tabs., refs

  17. Beam-beam issues in asymmetric colliders

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M.A.

    1992-07-01

    We discuss generic beam-beam issues for proposed asymmetric e{sup +}- e{sup -} colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II).

  18. High precision electron beam diagnostic system for high current long pulse beams

    International Nuclear Information System (INIS)

    As part of the effort to develop a multi-axis electron beam transport system using stripline kicker technology for DARHT II applications, it is necessary to precisely determine the position and extent of long high energy beams (6-40 MeV, 1-4 kA, 2 microseconds) for accurate position control. The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (<20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt measurements performed using capacitive pick-off probes. Likewise, transmission line traveling wave probes have problems with multi-bounce effects due to these longer pulse widths. Finally, the high energy densities experienced in these applications distort typical foil beam position measurements

  19. Anodic Behavior of Alloy 22 in Calcium Chloride and in Calcium Chloride Plus Calcium Nitrate Brines

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K J; Day, S D; Ilevbare, G O; Whalen, M T; King, K J; Hust, G A; Wong, L L; Estill, J C; Rebak, R B

    2003-05-13

    Alloy 22 (UNS N60622) is a nickel-based alloy, which is extensively used in aggressive industrial applications, especially due to its resistance to localized corrosion and stress corrosion cracking in high chloride environments. The purpose of this work was to characterize the anodic behavior of Alloy 22 in concentrated calcium chloride (CaCl{sub 2}) brines and to evaluate the inhibitive effect of nitrate, especially to localized corrosion. Standard electrochemical tests such as polarization resistance and cyclic polarization were used. Results show that the corrosion potential of Alloy 22 was approximately -360 mV in the silver-silver chloride (SSC) scale and independent of the tested temperature. Cyclic polarization tests showed that Alloy 22 was mainly susceptible to localized attack in 5 M CaCl{sub 2} at 75 C and higher temperatures. The addition of nitrate in a molar ratio of chloride to nitrate equal to 10 increased the onset of localized corrosion to approximately 105 C. The addition of nitrate to the solution also decreased the uniform corrosion rate and the passive current of the alloy.

  20. Electron beam treatment of textile dyeing wastewater

    International Nuclear Information System (INIS)

    A pilot plant with e-beam for treating 1,000m3/day of dyeing wastewater were constructed and started in operation from 1998, together with the biological treatment facility. The wastewater from various stages of the existing purification process can be treated with electron beam in this plant, and it will give rise to elaborate the optimal technology of the electron beam treatment of wastewater with increased reliability at instant changes in the composition of wastewater. Installation of the e-beam treatment results in decolorizing and destructive oxidation of organic impurities in wastewater, appreciable to reduction of chemical reagent consumption, in reduction of the treatment time, and in increase in flow rate limit of existing facilities by 30-40%. Commercial plants for treating over 10,000m3/day each, based upon this pilot experimental result, will start in construction from 2001 by the support of IAEA and Korean Government. (author)

  1. Update on calcium pyrophosphate deposition.

    Science.gov (United States)

    Abhishek, Abhishek; Doherty, Michael

    2016-01-01

    Calcium pyrophosphate crystal deposition (CPPD) associates with ageing, osteoarthritis (OA), uncommon metabolic diseases, mutations and polymorphisms in the ankylosis human gene (ANKH). CPPD is frequently polyarticular, occurs due to a generalised articular predisposition, and the association between CPPD and OA is joint specific, for example CPPD associates with knee OA, but not with hip OA. Other recently identified associations include knee malalignment (knee CC), low cortical BMD and soft-tissue calcification. CPPD is generally asymptomatic. A recent study reported that knees with OA plus CC at the index joint, or at distant joints (in absence of index joint CC), were more likely to have attrition. CPPD can cause acute CPP crystal arthritis, chronic CPP crystal inflammatory arthritis, and is frequently present in joints with OA. Joint aspiration remains the gold standard for diagnosing CPPD, although other promising techniques are emerging. Patients with polyarticular or young onset CPPD should be screened for underlying metabolic abnormalities, however, such testing can be unrewarding. The treatment of CPPD is symptomatic. Acute CPP crystal arthritis is treated with rest, local application of ice-packs, joint aspiration, colchicine and/or intra-articular corticosteroid injection (once infection is excluded). Colchicine, low-dose corticosteroids, hydroxychloroquine and radiosynovectomy are recommended for the treatment of chronic or recurrent acute CPP crystal arthritis. Recent RCTs did not confirm any benefit from methotrexate, and although there is increasing interest in the use of anti-IL1 agents for acute or chronic CPP crystal arthritis, their efficacy has not been formally examined. Unlike gout, currently there are no treatments to eliminate CPP crystal deposits. PMID:27586801

  2. Thai Research Reactor (TRR-1/M1) Neutron Beam Measurements

    International Nuclear Information System (INIS)

    Full text: Neutron beam tube of neutron radiography facility at Thai Research Reactor (TRR-1/M1) Thailand Institute of Nuclear Technology (public organization) is a divergent beam. The rectangular open-end of the beam tube is 16 cm x 17 cm while the inner-end is closed to the reactor core. The neutron beam size was measured using 20 cm x 40 cm neutron imaging plate. The measurement at the position 100 cm from the end of the collimator has shown that the beam size was 18.2 cm x 19.0 cm. Gamma ray in neutron the beam was also measured by the identical position using industrial X ray film. The area of gamma ray was 27.8 cm x 31.1 cm with the highest intensity found to be along the neutron beam circumference

  3. Beam Loss in Linacs

    CERN Document Server

    Plum, M A

    2016-01-01

    Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

  4. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...... beam is \\SI{4\\times10}{mm}. It is reinforced with a \\SI{3}{mm} high steel band covering the full width of the beam. The experimental setup is described and results for this beam are presented. Furthermore, the results for three similar experiments with a \\SI{6}{mm} steel band reinforcement are briefly...

  5. Space charge dominated beams

    International Nuclear Information System (INIS)

    After an introductory section on the relationship between emittance and beam Coulomb energy we discuss the properties of space charge dominated beams in progressive steps: from uniformly charged bunched beams to non-uniformly charged beams to correlation effects between particles (simulation beams or 'crystalline' beams). A practical application can be found in the beam dynamics of a high-current injector. The concept of correlation energy is of practical interest in computer simulation of high-brilliance beams, where one deals with an artificially enhanced two-particle Coulomb energy, if many real particles are combined into one simulation super-particle. This can be a source of non-physical emittance growth. (orig./HSI)

  6. Laser-Beam Separator

    Science.gov (United States)

    Mcdermid, I. S.

    1984-01-01

    Train of prisms and optical stop separate fundamental beam of laser from second and higher order harmonics of beam produced in certain crystals and by stimulated Raman scattering in gases and liquids.

  7. Eggshell powder, a comparable or better source of calcium than purified calcium carbonate: Piglet studies

    NARCIS (Netherlands)

    Schaafsma, A.; Beelen, G.M.

    1999-01-01

    Powdered chicken eggshells might be an interesting and widely available source of calcium. In two studies using piglets we determined the digestibility of calcium from different diets. The first study compared casein-based diets with CaCO3 (CasCC) or eggshell powder (CasES). The second study compare

  8. Calcium spikes and calcium plateaux evoked by differential polarization in dendrites of turtle motoneurones in vitro

    DEFF Research Database (Denmark)

    Hounsgaard, J; Kiehn, O

    1993-01-01

    The ability of dendrites in turtle motoneurones to support calcium spikes and calcium plateaux was investigated using differential polarization by applied electric fields. 2. Electric fields were generated by passing current through transverse slices of the turtle spinal cord between two plate...

  9. The L-Type Calcium Channel Blocker Nifedipine Impairs Extinction, but Not Reduced Contingency Effects, in Mice

    Science.gov (United States)

    Jami, Shekib; Barad, Mark; Cain, Christopher K.; Godsil, Bill P.

    2005-01-01

    We recently reported that fear extinction, a form of inhibitory learning, is selectively blocked by systemic administration of L-type voltage-gated calcium channel (LVGCC) antagonists, including nifedipine, in mice. We here replicate this finding and examine three reduced contingency effects after vehicle or nifedipine (40 mg/kg) administration.…

  10. Characterization of dihydropyridine-sensitive calcium channels

    International Nuclear Information System (INIS)

    The structural and regulatory properties of the dihydropyridine-sensitive calcium channel were studied by isolating protein components of the channel complex from both cardiac and skeletal muscle. Hydrodynamic characterization of the (+)-(3H)PN200-110-labeled cardiac calcium channel revealed that the protein components of the complex had a total molecular mass of 370,000 daltons, a Stokes radius of 86 angstrom, and a frictional ratio of 1.3. A technique is described for the rapid incorporation of the CHAPS solubilized skeletal muscle calcium channel complex into phospholipid vesicles. 45Ca2+ uptake into phospholipid vesicles containing calcium channels was inhibited by phenylalkalamine calcium antagonists. Wheat germ lectin followed by DEAE chromatography of the CHAPS solubilized complex resulted in the dissociation of regulatory components of the complex from channel components. The DEAE preparation gave rise to 45Ca2+ uptake that was not inhibited by verapamil but was inhibited by GTPgS activated G0. The inhibition of 45Ca2+ uptake by verapamil was restored by co-reconstitution of wash fractions from wheat germ lectin chromatography. Phosphorylation of polypeptides in this fraction by polypeptide-dependent protein kinase prevented the restoration of verapamil sensitivity. The partial purification of an endogenous skeletal muscle ADP-ribosyltransferase is also described. ADP-ribosylation of the α2 subunit of the calcium channel complex is enhanced by polylysine and inhibited by GTPγS, suggesting that regulation of this enzyme is under the control of GTP binding proteins. These results suggest a complex model, involving a number of different protein components, for calcium channel regulation in skeletal muscle

  11. Propagation of realistic beams in underdense plasma

    International Nuclear Information System (INIS)

    The effect of beam structure on propagation through underdense plasma is examined in two different examples. First, it is shown that the distribution of intensities within a laser beam affects how the beam deflects in the presence of transverse plasma flow. A detailed analysis of beam deflection shows that the rate scales linearly with intensity and plasma density, and inversely with plasma temperature. When the plasma flow is subsonic, the deflection rate is proportional to the ion damping decrement, and scales as M/(1 - M2)3/2, where M is the transverse flow Mach number. When the plasma flow is supersonic, the deflection rate scales as 1/[M(M2 - 1)1/2]. Next, the effect of beam structure on channel formation by very intense laser beer is studied. A diffraction-limited beam with 40 TW of input power forms a channel through 4OOpm of plasma, whereas when this beam is phase aberrated, channel formation does not occur

  12. Papillary and Nonpapillary Calcium Oxalate Monohydrate Renal Calculi: Comparative Study of Etiologic Factors

    OpenAIRE

    Enrique Pieras; Antonia Costa-Bauz; Margarita Ramis; Felix Grases

    2006-01-01

    Calcium oxalate monohydrate (COM) renal calculi can be classified into two groups: papillary and nonpapillary. In this paper, a comparative study between etiologic factors of COM papillary and nonpapillary calculi is performed. The study included 40 patients with COM renal calculi. The urine of these individuals was analyzed. Case history, lifestyle, and dietetic habits were obtained.No significant differences between urinary biochemical data of both groups were observed; 50% of COM papillary...

  13. PARTICLE BEAM TRACKING CIRCUIT

    Science.gov (United States)

    Anderson, O.A.

    1959-05-01

    >A particle-beam tracking and correcting circuit is described. Beam induction electrodes are placed on either side of the beam, and potentials induced by the beam are compared in a voltage comparator or discriminator. This comparison produces an error signal which modifies the fm curve at the voltage applied to the drift tube, thereby returning the orbit to the preferred position. The arrangement serves also to synchronize accelerating frequency and magnetic field growth. (T.R.H.)

  14. Beam Dynamics for ARIA

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl August Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-10-14

    Beam dynamics issues are assessed for a new linear induction electron accelerator being designed for flash radiography of large explosively driven hydrodynamic experiments. Special attention is paid to equilibrium beam transport, possible emittance growth, and beam stability. It is concluded that a radiographic quality beam will be produced possible if engineering standards and construction details are equivalent to those on the present radiography accelerators at Los Alamos.

  15. Slow kaon beams

    International Nuclear Information System (INIS)

    A short description is given of considerations for the design of low-momentum kaon beam lines. Relevant data for the performance of seven existing and decommissioned slow kaon beams are presented. For single-stage separated beams the observed ratio all/K- is greater than 50 for momenta less than 500 MeV/c. We recommend a two-stage separated beam with perhaps an upstream cleanup section for maximal purity

  16. Welding by laser beam

    International Nuclear Information System (INIS)

    A laser which does not require a vacuum and the beam from which can be projected over a distance without loss of power is sited outside a welding zone and the beam projected through a replaceable laser transparent window. The window is designed and shaped to facilitate access of the beam of workpiece items to be welded in containment. Either the workpiece or the laser beam may be moved during welding. (author)

  17. Proton beam writing

    OpenAIRE

    Frank Watt; Breese, Mark B H; Bettiol, Andrew A; Jeroen A. van Kan

    2007-01-01

    Proton beam (p-beam) writing is a new direct-writing process that uses a focused beam of MeV protons to pattern resist material at nanodimensions. The process, although similar in many ways to direct writing using electrons, nevertheless offers some interesting and unique advantages. Protons, being more massive, have deeper penetration in materials while maintaining a straight path, enabling p-beam writing to fabricate three-dimensional, high aspect ratio structures with vertical, smooth side...

  18. Electron beam focusing system

    Energy Technology Data Exchange (ETDEWEB)

    Dikansky, N.; Nagaitsev, S.; Parkhomchuk, V.

    1997-09-01

    The high energy electron cooling requires a very cold electron beam. Thus, the electron beam focusing system is very important for the performance of electron cooling. A system with and without longitudinal magnetic field is presented for discussion. Interaction of electron beam with the vacuum chamber as well as with the background ions and stored antiprotons can cause the coherent electron beam instabilities. Focusing system requirements needed to suppress these instabilities are presented.

  19. Biocompatibility and bone formation of flexible, cotton wool-like PLGA/calcium phosphate nanocomposites in sheep

    OpenAIRE

    Schneider, Oliver D; Mohn, Dirk; Fuhrer, Roland; Klein, Karina; Kämpf, Käthi; Nuss, Katja M; Sidler, Michèle; Zlinszky, Katalin; von Rechenberg, Brigitte; Stark, Wendelin J

    2011-01-01

    Background: The purpose of this preliminary study was to assess the in vivo performance of synthetic, cotton wool-like nanocomposites consisting of a biodegradable poly(lactide-co-glycolide) fibrous matrix and containing either calcium phosphate nanoparticles (PLGA/CaP 60:40) or silver doped CaP nanoparticles (PLGA/Ag-CaP 60:40). Besides its extraordinary in vitro bioactivity the latter biomaterial (0.4 wt% total silver concentration) provides additional antimicrobial properties for treating ...

  20. Carotid bifurcation calcium and correlation with percent stenosis of the internal carotid artery on CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    McKinney, Alexander M.; Casey, Sean O.; Teksam, Mehmet; Truwit, Charles L.; Kieffer, Stephen [University of Minnesota Medical School, Departments of Radiology, Minneapolis, MN (United States); Lucato, Leandro T. [Clinics Hospital, University of Sao Paulo, Sao Paulo (Brazil); Smith, Maurice [Johns Hopkins University, Department of Biomedical Engineering, Baltimore, MD (United States)

    2005-01-01

    The aim of this paper was to determine the correlation between calcium burden (expressed as a volume) and extent of stenosis of the origin of the internal carotid artery (ICA) by CT angiography (CTA). Previous studies have shown that calcification in the coronary arteries correlates with significant vessel stenosis, and severe calcification (measured by CT) in the carotid siphon correlates with significant (greater than 50% stenosis) as determined angiographically. Sixty-one patients (age range 50-85 years) underwent CT of the neck with intravenous administration of iodinated contrast for a variety of conditions. Images were obtained with a helical multidetector array CT scanner and reviewed on a three-dimensional workstation. A single observer manipulated window and level to segment calcified plaque from vascular enhancement in order to quantify vascular calcium volume (cc) in the region of the bifurcation of the common carotid artery/ICA origin, and to measure the extent of ICA stenosis near the origin. A total of 117 common carotid artery bifurcations were reviewed. A ''significant'' stenosis was defined arbitrarily as >40% (to detect lesions before they become hemodynamically significant) of luminal diameter on CTA using NASCET-like criteria. All ''significant'' stenoses (21 out of 117 carotid bifurcations) had measurable calcium. We found a relatively strong correlation between percent stenosis and the calcium volume (Pearson's r= 0.65, P<0.0001). We also found that there was an even stronger correlation between the square root of the calcium volume and the percent stenosis as measured by CTA (r= 0.77, P<0.0001). Calcium volumes of 0.01, 0.03, 0.06, 0.09 and 0.12 cc were used as thresholds to evaluate for a ''significant'' stenosis. A receiver operating characteristic (ROC) curve demonstrated that thresholds of 0.06 cc (sensitivity 88%, specificity 87%) and 0.03 cc (sensitivity 94%, specificity

  1. Carotid bifurcation calcium and correlation with percent stenosis of the internal carotid artery on CT angiography

    International Nuclear Information System (INIS)

    The aim of this paper was to determine the correlation between calcium burden (expressed as a volume) and extent of stenosis of the origin of the internal carotid artery (ICA) by CT angiography (CTA). Previous studies have shown that calcification in the coronary arteries correlates with significant vessel stenosis, and severe calcification (measured by CT) in the carotid siphon correlates with significant (greater than 50% stenosis) as determined angiographically. Sixty-one patients (age range 50-85 years) underwent CT of the neck with intravenous administration of iodinated contrast for a variety of conditions. Images were obtained with a helical multidetector array CT scanner and reviewed on a three-dimensional workstation. A single observer manipulated window and level to segment calcified plaque from vascular enhancement in order to quantify vascular calcium volume (cc) in the region of the bifurcation of the common carotid artery/ICA origin, and to measure the extent of ICA stenosis near the origin. A total of 117 common carotid artery bifurcations were reviewed. A ''significant'' stenosis was defined arbitrarily as >40% (to detect lesions before they become hemodynamically significant) of luminal diameter on CTA using NASCET-like criteria. All ''significant'' stenoses (21 out of 117 carotid bifurcations) had measurable calcium. We found a relatively strong correlation between percent stenosis and the calcium volume (Pearson's r= 0.65, P<0.0001). We also found that there was an even stronger correlation between the square root of the calcium volume and the percent stenosis as measured by CTA (r= 0.77, P<0.0001). Calcium volumes of 0.01, 0.03, 0.06, 0.09 and 0.12 cc were used as thresholds to evaluate for a ''significant'' stenosis. A receiver operating characteristic (ROC) curve demonstrated that thresholds of 0.06 cc (sensitivity 88%, specificity 87%) and 0.03 cc (sensitivity 94%, specificity 76%) generated the best combinations of sensitivity and

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

    Indian Academy of Sciences (India)

    B S Randhawa; Kamaljeet Sweety

    2000-08-01

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

  3. Calcium carbonate scaling kinetics determined from radiotracer experiments with calcium-47

    International Nuclear Information System (INIS)

    The deposition rate of calcium carbonate on a heat-transfer surface has been measured using a calcium-47 radiotracer and compared to the measured rate of thermal fouling. The crystalline phase of calcium carbonate that precipitates depends on the degree of supersaturation at the heat-transfer surface, with aragonite precipitating at higher supersaturations and calcite precipitating at lower supersaturations. Whereas the mass deposition rates were constant with time, the thermal fouling rates decreased throughout the course of each experiment as a result of densification of the deposit. It is proposed that the densification was driven by the temperature gradient across the deposit together with the retrograde solubility of calcium carbonate. The temperature dependence of the deposition rate yielded an activation energy of 79 ± 4 kJ/mol for the precipitation of calcium carbonate on a heat-transfer surface. (author)

  4. Skin injuries afflicting three oil workers following contact with calcium bromide and/or calcium chloride.

    Science.gov (United States)

    Saeed, W R; Distante, S; Holmes, J D; Kolhe, P S

    1997-01-01

    Calcium bromide brine is a highly concentrated aqueous solution of calcium bromide and calcium chloride. It is used extensively in the oil industry. This solution and its components are recognized as causes of skin injury and information is available from the manufacturers on their safe use and handling. Two patients who were injured following unprotected skin exposure to this solution and one patient who was injured following exposure to calcium chloride powder are reported. All sustained skin injuries characterised by an absence of pain and a delayed clinical appearance of the full extent of the injury. Furthermore healing was complicated by graft loss or was slow. Although organic bromine compounds are recognized as a cause of skin injuries, no previous reports of such injuries to humans secondary to calcium chloride or bromide exposure were found in the medical literature. Our experience with these patients is described. PMID:9568340

  5. Effect of dietary calcium and phosphorus on intestinal calcium absorption and vitamin D metabolism

    International Nuclear Information System (INIS)

    To understand better dietary regulation of intestinal calcium absorption, a quantitative assessment of the metabolites in plasma and duodenum of rats given daily doses of radioactive vitamin D3 and diets differing in calcium and phosphorus content was made. All known vitamin D metabolites were ultimately identified by high-pressure liquid chromatography. In addition to the known metabolites (25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D3, 1,25-dihydroxyvitamin D3, 25,26-dihydroxyvitamin D3, and 1,24,25-trihydroxyvitamin D3), several new and unidentified metabolites were found. In addition to 1,25-dihydroxyvitamin D3 and 1,24,25-trihydroxyvitamin D3, the levels of some of the unknown metabolites could be correlated with intestinal calcium transport. However, whether or not any of these metabolites plays a role in the stimulation of intestinal calcium absorption by low dietary calcium or low dietary phosphorus remains unknown

  6. Removal of Pb (II from Aqueous Solutions Using Mixtures of Bamboo Biochar and Calcium Sulphate, and Hydroxyapatite and Calcium Sulphate

    Directory of Open Access Journals (Sweden)

    Ahmed Hassan

    2016-01-01

    Full Text Available Sorption characteristics of Pb(II from aqueous solutions through a low-cost adsorbent mixture comprising of Bamboo biochar (BB and Calcium Sulphate (CS, and a more expensive mixture of Hydroxyapatite (HAP and Calcium Sulphate (CS, were investigated. The effects of equilibrium contact time, and adsorbate concentration conducted in batch experiments were studied. Adsorption equilibrium was established in 40 (min. The adsorption mechanism of Pb(II from these two adsorbent mixtures was carried out through a kinetic rate order. A pseudo second-order kinetic model was applied for the adsorption processes. The model yielded good correlation (R2 >0.999 of the experimental data. Adsorption of Pb(II using (BB&CS and (HAP&CS correlated well (R2 >0.99 with both the Langmuir and Freundlich isotherm equations under the concentration range studied. Hence, the effectiveness of an inexpensive natural material (BB&CS mixture in Pb(II removal is established, and is promising for use in other heavy metal adsorptions.

  7. Beam injection into RHIC

    International Nuclear Information System (INIS)

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. The authors describe the injection zone and its bottlenecks. They report on the commissioning of the injection system, on beam based measurements of the kickers and the application program to steer the beam

  8. Beams 92: Proceedings

    International Nuclear Information System (INIS)

    This report contains papers on the following topics: Ion beam papers; electron beam, bremsstrahlung, and diagnostics papers; radiating Z- pinch papers; microwave papers; electron laser papers; advanced accelerator papers; beam and pulsed power applications papers; pulsed power papers; and these papers have been indexed separately elsewhere

  9. An Electromagnetic Beam Converter

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to an electromagnetic beam converter and a method for conversion of an input beam of electromagnetic radiation having a bell shaped intensity profile a(x,y) into an output beam having a prescribed target intensity profile l(x',y') based on a further development of the...

  10. Klystron beam bunching

    International Nuclear Information System (INIS)

    A detailed description of electron-beam bunching phenomena in klystrons is presented. Beam harmonic current is defined, both space-charge and ballistic bunching are analyzed, Ramo's theorem is used to describe how a bunched beam drives a cavity, and a general cavity model including external coupling is provided. (author)

  11. Accelerating nondiffracting beams

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Shaohui; Li, Manman; Yao, Baoli, E-mail: yaobl@opt.ac.cn; Yu, Xianghua; Lei, Ming; Dan, Dan; Yang, Yanlong; Min, Junwei; Peng, Tong

    2015-06-05

    We present a set of beams which combine the properties of accelerating beams and (conventional) diffraction-free beams. These beams can travel along a desired trajectory while keeping an approximately invariant transverse profile, which may be (higher-order) Bessel-, Mathieu- or parabolic-nondiffracting-like beams, depending on the initial complex amplitude distribution. A possible application of these beams presented here may be found in optical trapping field. For example, a higher-order Bessel-like beam, which has a hollow (transverse) pattern, is suitable for guiding low-refractive-index or metal particles along a curve. - Highlights: • A set of beams having arbitrary trajectories of accelerating and nondiffracting behaviors are generalized and presented. • Bessel-like accelerating beams are generalized to the higher-order (hollow) version. • Mathieu-like accelerating beams and parabolic-nondiffracting-like accelerating beams are presented. • A possible application of these beams may be found in optical trapping and guiding of particles.

  12. Bone calcium turnover during pregnancy and lactation in women with low calcium diets is associated with calcium intake and circulating insulin-like growth factor 1 concentrations

    Science.gov (United States)

    BACKGROUND: Few data exist on longitudinal changes in bone calcium turnover rates across pregnancy and lactation. OBJECTIVE: Our aim was to characterize calcium kinetic variables and predictors of these changes across pregnancy and early lactation in women with low calcium intakes. DESIGN: Stable ca...

  13. Role of mitochondria and network connectivity in intercellular calcium oscillations

    CERN Document Server

    Dokukina, I V; Grachev, E A; Gunton, J D; Dokukina, Irina V.; Gracheva, Maria E.; Grachev, Eugene A.; Gunton, James D.

    2005-01-01

    Mitochondria are large-scale regulators of cytosolic calcium under normal cellular conditions. In this paper we model the complex behavior of mitochondrial calcium during the action of inositol 1,4,5-trisphosphate on a single cell and find results that are in good agreement with recent experimental studies. We also study the influence of the cellular network connectivity on intercellular signalling via gap junction diffusion. We include in our model the dependence of the junctional conductivity on the cytosolic calcium concentrations in adjacent cells. We consider three different mechanisms of calcium wave propagation through gap junctions: via calcium diffusion, inositol 1,4,5-trisphosphate diffusion, and both calcium and inositol 1,4,5-trisphosphate diffusion. We show that inositol 1,4,5-trisphosphate diffusion is the mechanism of calcium wave propagation and that calcium diffusion is the mechanism of synchronization of cytosolic calcium oscillations in adjacent cells. We also study the role of different to...

  14. 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.

  15. In-situ observation on the transformation of calcium phosphate cement into hydroxyapatite

    International Nuclear Information System (INIS)

    In the present study, the in-situ transformation of calcium phosphate cement into hydroxyapatite (HAp) within the first hour is monitored with a synchrotron X-ray beam. A disodium hydrogen phosphate solution is used as cement liquid to activate the reaction between dicalcium phosphate anhydrous (DCPA) and calcium hydroxide (Ca(OH)2). The XRD analysis indicates that the amounts of DCPA and Ca(OH)2 first decrease within the first min of the reaction. Then, the intensity of DCPA's XRD peaks starts to increase instead in the period of 5 to 20 min. After 20 min, the DCPA particles are consumed slowly to form fine HAp particles. Large pores are evident upon the completion of reaction.

  16. Calcium phosphate holmium-166 ceramic to addition in bone cement: synthesis and characterization

    International Nuclear Information System (INIS)

    Spine metastases are a common and painful complication of cancer. The treatment often consists of bone cement injection (vertebroplasty or kyphoplasty) within vertebral body for vertebrae stabilization, followed by external beam radiation therapy. Recently, researchers introduced the concept of radioactive bone cement for spine tumors therapy. Then, investigations about bioactive and radioactive materials became interesting. In this study, we present the synthesis of calcium phosphate incorporated holmium (CaP-Ho) via sol-gel technique, and its characterization by XRD, FT-IR, NA and SEM. Results showed a multiphasic bioceramic composed mainly of hydroxyapatite, β-tricalcium phosphate, holmium phosphate and traces of calcium pyrophosphate. Furthermore, the nuclide Ho-166 was the major radioisotope produced. Despite that, the radioactive bioceramic CaP-166Ho must be investigated in clinical trials to assure its efficacy and safety on spine tumors treatment (author)

  17. Calcium phosphate holmium-166 ceramic to addition in bone cement: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Donanzam, Blanda A.; Campos, Tarcisio P.R., E-mail: campos@nuclear.ufmg.b [Universidade do Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Dept. de Engenharia Nuclear; Dalmazio, Ilza; Valente, Eduardo S., E-mail: id@cdtn.b, E-mail: valente@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    Spine metastases are a common and painful complication of cancer. The treatment often consists of bone cement injection (vertebroplasty or kyphoplasty) within vertebral body for vertebrae stabilization, followed by external beam radiation therapy. Recently, researchers introduced the concept of radioactive bone cement for spine tumors therapy. Then, investigations about bioactive and radioactive materials became interesting. In this study, we present the synthesis of calcium phosphate incorporated holmium (CaP-Ho) via sol-gel technique, and its characterization by XRD, FT-IR, NA and SEM. Results showed a multiphasic bioceramic composed mainly of hydroxyapatite, {beta}-tricalcium phosphate, holmium phosphate and traces of calcium pyrophosphate. Furthermore, the nuclide Ho-166 was the major radioisotope produced. Despite that, the radioactive bioceramic CaP-{sup 166}Ho must be investigated in clinical trials to assure its efficacy and safety on spine tumors treatment (author)

  18. 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.

  19. Vitamin D with Calcium Reduces Mortality

    DEFF Research Database (Denmark)

    Rejnmark, Lars; Avenell, Alison; Masud, Tahir;

    2012-01-01

    ,528 randomized participants (86.8% females) with a median age of 70 (interquartile range, 62-77) yr. Vitamin D with or without calcium reduced mortality by 7% [hazard ratio, 0.93; 95% confidence interval (CI), 0.88-0.99]. However, vitamin D alone did not affect mortality, but risk of death was reduced if vitamin...... D was given with calcium (hazard ratio, 0.91; 95% CI, 0.84-0.98). The number needed to treat with vitamin D plus calcium for 3 yr to prevent one death was 151. Trial level meta-analysis (24 trials with 88,097 participants) showed similar results, i.e. mortality was reduced with vitamin D plus...... calcium (odds ratio, 0.94; 95% CI, 0.88-0.99), but not with vitamin D alone (odds ratio, 0.98; 95% CI, 0.91-1.06).Conclusion:Vitamin D with calcium reduces mortality in the elderly, whereas available data do not support an effect of vitamin D alone....

  20. Calcium and bone disorders in pregnancy

    Directory of Open Access Journals (Sweden)

    Shriraam Mahadevan

    2012-01-01

    Full Text Available Significant transplacental calcium transfer occurs during pregnancy, especially during the last trimester, to meet the demands of the rapidly mineralizing fetal skeleton. Similarly, there is an obligate loss of calcium in the breast milk during lactation. Both these result in considerable stress on the bone mineral homeostasis in the mother. The maternal adaptive mechanisms to conserve calcium are different in pregnancy and lactation. During pregnancy, increased intestinal absorption of calcium from the gut mainly due to higher generation of calcitriol (1,25 dihydroxy vitamin D helps in maintaining maternal calcium levels. On the other hand, during lactation, the main compensatory mechanism is skeletal resorption due to increased generation of parathormone related peptide (PTHrP from the breast. Previous studies suggest that in spite of considerable changes in bone mineral metabolism during pregnancy, parity and lactation are not significantly associated with future risk for osteoporosis. However, in India, the situation may not be the same as a significant proportion of pregnancies occur in the early twenties when peak bone mass is not yet achieved. Further, malnutrition, anemia and vitamin D deficiency are commonly encountered in this age group. This may have an impact on future bone health of the mother. It may also probably provide an opportunity for health care providers for prevention. Other metabolic bone diseases like hypoparathyroidism, hyperparathyroidism and pseudohypoparathyroidism are rarely encountered in pregnancy. Their clinical implications and management are also discussed.

  1. Calcium And Zinc Deficiency In Preeclamptic Women

    Directory of Open Access Journals (Sweden)

    Sultana Ferdousi

    2011-12-01

    Full Text Available Background: Pre-eclampsia is the most common medical complication of pregnancy associated withincreased maternal and infant mortality and morbidity. Reduced serum calcium and zinc levels arefound associated with elevated blood pressure in preeclampsia. Objective: To observe serum calciumand zinc levels in preeclamptic women. Methods: This cross sectional study was carried out in theDepartment of Physiology, Bangabandhu Sheikh Mujib Medical University, Shahbag, Dhaka betweenJuly 2009 to June 2010. In this study, 60 pregnant women of preeclampsia, aged 18-39 years withgestational period more than 20th weeks were included as the study (group B. For comparison ageand gestational period matched 30 normotensive pregnant women control (group A were also studied.All the subjects were selected from Obstetric and Gynae In and Out patient Department of BSMMUand Dhaka Medical College Hospital. Serum calcium was measured by Colorimetric method and serumzinc was measured by Spectrophotometric method. Data were analysed by independent sample t testand Pearson’s correlation coefficient test. Results: Mean serum calcium and zinc levels weresignificantly (p<0.001 lower in study group than those of control group. Again, serum calcium andzinc showed significant negative correlation with SBP and DBP in preeclamptic women. Conclusion:This study concludes that serum calcium and zinc deficiency may be one of the risk factor ofpreeclampsia. Therefore, early detection and supplementation to treat this deficiency may reduce theincidence of preeclampsia.

  2. Calcium's Role in Mechanotransduction during Muscle Development

    Directory of Open Access Journals (Sweden)

    Tatiana Benavides Damm

    2014-01-01

    Full Text Available Mechanotransduction is a process where cells sense their surroundings and convert the physical forces in their environment into an appropriate response. Calcium plays a crucial role in the translation of such forces to biochemical signals that control various biological processes fundamental in muscle development. The mechanical stimulation of muscle cells may for example result from stretch, electric and magnetic stimulation, shear stress, and altered gravity exposure. The response, mainly involving changes in intracellular calcium concentration then leads to a cascade of events by the activation of downstream signaling pathways. The key calcium-dependent pathways described here include the nuclear factor of activated T cells (NFAT and mitogen-activated protein kinase (MAPK activation. The subsequent effects in cellular homeostasis consist of cytoskeletal remodeling, cell cycle progression, growth, differentiation, and apoptosis, all necessary for healthy muscle development, repair, and regeneration. A deregulation from the normal process due to disuse, trauma, or disease can result in a clinical condition such as muscle atrophy, which entails a significant loss of muscle mass. In order to develop therapies against such diseased states, we need to better understand the relevance of calcium signaling and the downstream responses to mechanical forces in skeletal muscle. The purpose of this review is to discuss in detail how diverse mechanical stimuli cause changes in calcium homeostasis by affecting membrane channels and the intracellular stores, which in turn regulate multiple pathways that impart these effects and control the fate of muscle tissue.

  3. Pushing the limits - beam

    CERN Document Server

    Métral, E

    2011-01-01

    Many collective effects were observed in 2010, first when the intensity per bunch was increased and subsequently when the number of bunches was pushed up and the bunch spacing was reduced. After a review of the LHC performance during the 2010 run, with a particular emphasis on impedances and related single-beam coherent instabilities, but mentioning also beam-beam and electron cloud issues, the potential of the LHC for 2011 will be discussed. More specifically, the maximum bunch/beam intensity and the maximum beam brightness the LHC should be able to swallow will be compared to what the injectors can provide.

  4. Association of Urinary Calcium Excretion with Serum Calcium and Vitamin D Levels

    Science.gov (United States)

    Rathod, Anita; Bonny, Olivier; Guessous, Idris; Suter, Paolo M.; Conen, David; Erne, Paul; Binet, Isabelle; Gabutti, Luca; Gallino, Augusto; Muggli, Franco; Hayoz, Daniel; Péchère-Bertschi, Antoinette; Paccaud, Fred

    2015-01-01

    Background and objectives Population-based data on urinary calcium excretion are scarce. The association of serum calcium and circulating levels of vitamin D [25(OH)D2 or D3] with urinary calcium excretion in men and women from a population-based study was explored. Design, settings, participants, & measurements Multivariable linear regression was used to explore factors associated with square root–transformed 24-hour urinary calcium excretion (milligrams per 24 hours) taken as the dependent variable with a focus on month-specific vitamin D tertiles and serum calcium in the Swiss Survey on Salt Study. Results In total, 624 men and 669 women were studied with mean ages of 49.2 and 47.0 years, respectively (age range=15–95 years). Mean urinary calcium excretion was higher in men than in women (183.05 versus 144.60 mg/24 h; P<0.001). In adjusted models, the association (95% confidence interval) of square root urinary calcium excretion with protein–corrected serum calcium was 1.78 (95% confidence interval, 1.21 to 2.34) mg/24 h per milligram per deciliter in women and 0.59 (95% confidence interval, −0.11 to 1.29) mg/24 h per milligram per deciliter in men. Men in the third 25(OH)D3 tertile had higher square root urinary calcium excretion than men in the first tertile (0.99; 95% confidence interval, 0.36 to 1.63 mg/24 h per nanogram per milliliter), and the corresponding association was 0.32 (95% confidence interval, −0.22 to 0.85) mg/24 h per nanogram per milliliter in women. These sex differences were more marked under conditions of high urinary sodium or urea excretions. Conclusions There was a positive association of serum calcium with urinary calcium excretion in women but not men. Vitamin 25(OH)D3 was associated with urinary calcium excretion in men but not women. These results suggest important sex differences in the hormonal and dietary control of urinary calcium excretion. PMID:25518946

  5. In vivo measurement of calcium by prompt-gamma neutron activation analysis

    International Nuclear Information System (INIS)

    This paper describes phantom experiments to assess the feasibility of measuring both part- and total-body calcium by the prompt - as opposed to the more usual delayed - neutron activation technique. The results indicate that a 30 min irradiation of a 20 cm length of the lumbar spine with a collimated beam of 252Cf neutrons, would yield approximately 2500 counts in the 6.420 MeV main and escape peaks, with a statistical precision of less than 5%, for a dose equivalent of 20 mSv. The proposed detection system, consisting of two 20% efficient germanium detectors positioned above the subject, i.e. on the side opposite the incident neutron beam, would provide improved uniformity of measurement compared with the usual situation where activation and counting are performed from the same side. The on-line technique also enables the subject to be scanned across the neutron beam to provide a measure of total-body calcium. In this case it would be possible to make an analysis to the same degree of precision for an average whole-body dose equivalent of only 1 to 1.3 mSv. 10 references, 3 figures, 1 table

  6. Nuclear reaction studies with radioactive 17 F beams

    International Nuclear Information System (INIS)

    Full text: Radioactive 17 F beams were produced at the Holifield Radioactive Ion Beam Facility using the Isotope Separator On Line (ISOL) technique. A 40 MeV deuteron beam provided by the Oak Ridge Isochronous Cyclotron (ORIC) was used to bombard a hafnium oxide target to produce 17 F by the 16 O(d,n) reaction. The 17 F ions were mass analysed and subsequently accelerated by the 25 MV tandem. Two of the experiments using accelerated 17 F beams will be reported: the breakup of 170 MeV 17 F by 208 Pb and the simultaneous emission of two protons from a resonance in 18 Ne. (Author)

  7. Strain in silicon nanowire beams

    Science.gov (United States)

    Ureña, Ferran; Olsen, Sarah H.; Šiller, Lidija; Bhaskar, Umesh; Pardoen, Thomas; Raskin, Jean-Pierre

    2012-12-01

    In this work, strain in silicon free standing beams loaded in uniaxial tension is experimentally and theoretically investigated for strain values ranging from 0 to 3.6%. The fabrication method allows multiple geometries (and thus strain values) to be processed simultaneously on the same wafer while being studied independently. An excellent agreement of strain determined by two non-destructive characterization techniques, Raman spectroscopy and mechanical displacement using scanning electron microscopy (SEM) markers, is found for all the sample lengths and widths. The measured data also show good agreement with theoretical predictions of strain based upon continuum mechanical considerations, giving validity to both measurement techniques for the entire range of strain values. The dependence of Young's modulus and fracture strain on size has also been analyzed. The Young's modulus is determined using SEM and compared with that obtained by resonance-based methods. Both methods produced a Young's modulus value close to that of bulk silicon with values obtained by resonance-based methods being slightly lower. Fracture strain is analyzed in 40 sets of samples with different beam geometries, yielding values up to 3.6%. The increase in fracture strain with decreasing beam width is compared with previous reports. Finally, the role of the surface on the mechanical properties is analyzed using UV and visible lasers having different penetration depths in silicon. The observed dependence of Raman shift on laser wavelength is used to assess the thermal conductivity of deformed silicon.

  8. Cluster ion beam evaporation

    International Nuclear Information System (INIS)

    Cluster ions can be made by the supercooling due to adiabatic expansion of substances to be vaporized which are ejected from a nozzle. This paper is described on the recent progress of studies concerning the cluster beam. The technique of cluster ion beam has been applied for the studies of thermonuclear plasma, the fabrication of thin films, crystal growth and electronic devices. The density of cluster ion beam is larger than that of atomic ion beam, and the formation of thin films can be easily done in high vacuum. This method is also useful for epitaxial growth. Metallic vapour cluster beam was made by the help of jetting rare gas beam. Various beam sources were developed. The characteristics of these sources were measured and analyzed. (Kato, T.)

  9. Dynamics of beam halo in mismatched beams

    International Nuclear Information System (INIS)

    High-power proton linacs for nuclear materials transmutation and production, and new accelerator-driven neutron spallation sources must be designed to control beam-halo formation, which leads to beam loss. The study of particle-core models is leading to a better understanding of the causes and characteristics of beam halo produced by space-charge forces in rms mismatched beams. Detailed studies of the models have resulted in predictions of the dependence of the maximum amplitude of halo particles on a mismatch parameter and on the space-charge tune-depression ratio. Scaling formulas have been derived which will provide guidance for choosing the aperture radius to contain the halo without loss. (author)

  10. Luminescent properties of calcium iodide crystals

    International Nuclear Information System (INIS)

    The influence of preparation conditions, temperature and X radiation on luminescent properties of calcium iodide scintillating crystals is studied, the results are provided. The results obtained when studying spectral characteristics of CaI2 and CaI2:H2 crystals in case of optical and X-ray excitation in the temperature range of 90-400 K, allowance made for data obtained when studying luminescent properties of calcium iodide crystals activated by Cl-, Br-, OH- and Ca2+ impurities, permit assumption that band 236 nm observed in excitation spectra of calcium iodide crystals can stem from noncontrolled hydrogen impurity. Luminescence of the crystals with the maximum in the range of 395 nm is assigned to radiation recombination of excitons localized on H- ions

  11. Calcium metabolism evaluated by 47Ca kinetics

    International Nuclear Information System (INIS)

    Optimization of a four-crystal stretcher geometry whole-body (WB) counter was performed. The measured geometric characteristic did not differ significantly from the theoretically calculated characteristic (p>0.05). The linearity of the WB counter was high in the range 3.7 kBq to 3.7 MBq. Longtime variability of local background was CV = 3.7 per cent. In vivo sensitivity was calculated to 18 cpm/kBq and the detection limit to about 5 kBq. The reproducibility was estimated to 0.7 per cent. The WB counter was used in 47Ca turnover and calcium balance studies of 15 normal individuals. The data were analysed according to a modification of the expanding calcium pool model using an improved Bauer-Carlsson-Lindquist formulation. Variability and method errors of main parameters for calcium metabolism were evaluated. (Auth.)

  12. Glial calcium signaling in physiology and pathophysioilogy

    Institute of Scientific and Technical Information of China (English)

    Alexei VERKHRASKY

    2006-01-01

    Neuronal-glial circuits underlie integrative processes in the nervous system.Function of glial syncytium is,to a very large extent,regulated by the intracellular calcium signaling system.Glial calcium signals are triggered by activation of multiple receptors,expressed in glial membrane,which regulate both Ca2+ entry and Ca2+ release from the endoplasmic reticulum.The endoplasmic reticulum also endows glial cells with intracellular excitable media,which is able to produce and maintain long-ranging signaling in a form of propagating Ca2+ waves.In pathological conditions,calcium signals regulate glial response to injury,which might have both protective and detrimental effects on the nervous tissue.

  13. X-ray fluorescence with synchrotron radiation to elemental analysis of lead and calcium content of primary teeth

    International Nuclear Information System (INIS)

    Primary teeth were analyzed by micro-SRXRF. The aim of this study was to determine the elemental distribution of lead and calcium in different regions of primary incisor of children living in a notoriously contaminated area (Santo Amaro da Purificacao, Bahia State, Brazil). The measurements were performed in standard geometry of 45 deg. incidence, exciting with a white beam and using a conventional system collimation (orthogonal slits) in the XRF beamline at the Synchrotron Light National Laboratory (Campinas, Brazil).

  14. 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

  15. 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.

  16. Characterization of Calcium Compounds in Opuntia ficus indica as a Source of Calcium for Human Diet

    Directory of Open Access Journals (Sweden)

    Isela Rojas-Molina

    2015-01-01

    Full Text Available Analyses of calcium compounds in cladodes, soluble dietary fiber (SDF, and insoluble dietary fiber (IDF of Opuntia ficus indica are reported. The characterization of calcium compounds was performed by using Scanning Electron Microscopy, Energy Dispersive Spectrometry, X-ray diffraction, and infrared spectroscopy. Atomic Absorption Spectroscopy and titrimetric methods were used for quantification of total calcium and calcium compounds. Whewellite (CaC2O4·H2O, weddellite (CaC2O4·(H2O2.375, and calcite (CaCO3 were identified in all samples. Significant differences (P≤0.05 in the total calcium contents were detected between samples. CaC2O4·H2O content in cladodes and IDF was significantly higher (P≤0.05 in comparison to that observed in SDF, whereas minimum concentration of CaCO3 was detected in IDF with regard to CaCO3 contents observed in cladodes and SDF. Additionally, molar ratio oxalate : Ca2+ in all samples changed in a range from 0.03 to 0.23. These results support that calcium bioavailability in O. ficus indica modifies according to calcium compounds distribution.

  17. 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.

  18. Calcium deposits in the common carotid artery

    International Nuclear Information System (INIS)

    Complete text of publication follows. Arterial calcification consists mainly of calcium apatite and takes place at two sites in the vessel wall: the intima and the media. Intimal calcification occurs exclusively within atherosclerotic plaques, while medial calcification may develop independently [1]. Ultrasound examination of the carotid arteries is performed routinely to assess pathological alterations. Large calcified plaques in the carotid arteries can be detected by B-mode ultrasonography easily as high frequency ultrasound does not penetrate calcium and have been investigated extensively. In this study our aim was to determine the calcium distribution in the vessel wall itself, excluding large plaques, and to make the first step towards investigating the relationship between the calcium distributional maps and the respective ultrasonic images. The carotid arteries of five elderly (age 71±9 years) and one young (age 27 years) deceased patients were excised at autopsy and were investigated with a medical ultrasound equipment in a tank containing saline solution. Scan sequences were videotaped and images of previously marked cross-sections were transferred to a computer. Small pieces of the arteries were cut and quench frozen. Sections of 60μm from the middle of the scanned segments (30mm proximal to the bifurcation) were cut in a cryostat. The cryosections were transferred to microprobe target holders. The elemental distribution of the samples were determined by particle induced X-ray emission (PIXE) at the Debrecen microprobe [2]. True elemental maps and absolute concentration values were evaluated with a new software (True Pixe Imaging) [3]. The average calcium content of the scanned areas varied between 1000 and 9000μg/g in the slices of the common carotid arteries of the elderly patients. In contrast, scanned areas in the slices from the young subject contained only 600-800μg/g calcium. The concentration of calcium could reach even 3.75% along the wide

  19. NMR study of hydrated calcium silicates

    International Nuclear Information System (INIS)

    Radioactive wastes storage methods are developed by the CEA. As cements are important materials as well for hours living radioisotopes than for years living radioisotopes, a better knowledge of this material will allow to anticipate its behaviour and to obtain safer storage methods. The structure of calcium silicates (C-S-H) (main constituent of cements) have then been determined in this thesis by nuclear magnetic resonance. This method has allow to explain in structural terms, the different calcium rates that can be measured in the C-S-H too. (O.M.)

  20. Synthesis and characterization of porous calcium phosphate

    International Nuclear Information System (INIS)

    The porous calcium phosphate was prepared by the continuous precipitation method using Ca(NO3)2.4H2O and NH4H2PO4 salts. The synthesized material was structurally and superficially characterized using the XRD, BET, IR TGA and SEM techniques. The obtained inorganic material was identified as calcium phosphate that presents a great specific area for what can be efficiently used as adsorbent material for adsorption studies in the radioactive wastes treatment present in aqueous solution. (Author)