Sample records for calcium 60

  1. Calcium (United States)

    ... Turn to calcium-fortified (or "calcium-set") tofu, soy milk, tempeh, soy yogurt, and cooked soybeans (edamame). Calcium-fortified foods. Look for calcium-fortified orange juice, soy or rice milk, breads, and cereal. Beans. You can get decent ...

  2. Calcium (United States)

    ... and blood vessels contract and expand, to secrete hormones and enzymes and to send messages through the nervous system. It is important to get plenty of calcium in the foods you eat. Foods rich in calcium include Dairy products such as milk, cheese, and yogurt Leafy, green vegetables Fish with ...

  3. Calcium (United States)

    ... from dietary supplements are linked to a greater risk of kidney stones, especially among older adults. But calcium from foods does not appear to cause kidney stones. For most people, other factors (such as not drinking enough fluids) probably have ...

  4. Calcium - urine (United States)

    Urinary Ca+2; Kidney stones - calcium in urine; Renal calculi - calcium in your urine; Parathyroid - calcium in urine ... Urine calcium level can help your provider: Decide on the best treatment for the most common type of kidney ...

  5. Calcium Carbonate (United States)

    Calcium carbonate is a dietary supplement used when the amount of calcium taken in the diet is not ... for healthy bones, muscles, nervous system, and heart. Calcium carbonate also is used as an antacid to relieve ...

  6. Calcium supplements (United States)

    ... this page: // 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 ...

  7. Effect of calcium oxide inclusion in beef feedlot diets containing 60% dried distillers grains with solubles on ruminal fermentation, diet digestibility, performance, and carcass characteristics. (United States)

    Nuñez, A J C; Felix, T L; Lemenager, R P; Schoonmaker, J P


    Two experiments were conducted to determine the effect of increasing dietary CaO on ruminal fermentation, diet digestibility, performance, and carcass characteristics of feedlot steers fed 60% dried distillers grains with solubles ( DDGS: ). In Exp. 1, 120 steers were allotted by weight (355 ± 7.9 kg) to 1 of 4 treatments containing 60% DDGS, 20% corn silage, 13.5 to 14.4% ground corn, 4% supplement, and 0 to 2.5% limestone on DM basis to determine the effects of CaO on performance and carcass characteristics. Treatments consisted of 0, 0.8, 1.6, or 2.4% CaO inclusion in the diet (DM basis), with CaO replacing limestone. Steers were slaughtered at a target BW of approximately 641 kg. In Exp. 2, 4 steers (initial BW = 288 ± 3 kg) were randomly allotted to the same diets in a 4 × 4 Latin square design (14-d periods) to determine the effects of CaO on ruminal pH, VFA, and nutrient digestibility. Statistical analyses were conducted using the MIXED procedure of SAS. Inclusion of CaO at 0.8, 1.6, and 2.4% increased ADG by 5.0, 3.9, and 0%, respectively, compared to 0% CaO (quadratic; P = 0.03). Intake was linearly decreased (P = 0.04) and G:F was linearly increased (P = 0.02) by CaO inclusion. Dressing percentage increased as CaO increased from 0 to 1.6% and then decreased for 2.4% CaO (quadratic; P diets. Inclusion of CaO up to 1.6% was effective in improving performance of feedlot cattle.

  8. Calcium Electroporation

    DEFF Research Database (Denmark)

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


    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

  9. Calcium Intake in the Moroccan Elderly

    Directory of Open Access Journals (Sweden)

    Sebbar El-houcine


    Full Text Available Introduction: Calcium intakes of elderly people are often below the recommendations which are 1200 mg/day. The advancing age may be accompanied by a loss of capacity to absorb additional calcium in case of deficiency. The aim of our work is to evaluate the calcium intake in the Moroccan elderly. Methods: The version translated into Arabic dialect Fardellone questionnaire is tested on a sample of 159 subjects aged over 60 years. Results: The study population includes 87 women (55%, 72 men (45%. The mean calcium intake was respectively 3078 mg by week (that means 440 mg/day. The assessment of calcium intake showed a deficiency and the average consumption of calcium per day is significantly lower than the recommended daily amount for this population. The comparison of both gender found a deficit higher among women than among men. Conclusion: Evaluation of the calcium intake is an essential tool for better management of metabolic bone diseases.

  10. Calcium Impact on Milk Gels Formation

    DEFF Research Database (Denmark)

    Koutina, Glykeria

    Calcium is one of the several elements that can be found in milk distributed between the micellar and the serum milk phase. Calcium is important from a nutritional point of view, but its contribution to the functional and structural properties of dairy products has only recently been...... acknowledgement. The presence of calcium in a dynamic equilibrium between the serum and the micellar milk phase make the distribution susceptible to certain physicochemical conditions and to technological treatments of milk resulting in fluctuations in pH and temperature and also sensitive to addition of calcium...... salts. The perturbation of calcium equilibria by these factors will affect the final properties of acid, calcium and rennet milk gels. By decreasing the pH from 6.0 to 5.2 (acid gels), the calcium equilibrium was significantly affected by temperature (4, 20, 30, 40 oC), and different combinations...

  11. Get Enough Calcium (United States)

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... women, don't get enough calcium. How much calcium do I need every day? Women: If you ...

  12. Calcium carbonate overdose (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 ...

  13. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

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


    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,

  14. Coronary Calcium Scan (United States)

    ... Back To Health Topics / Coronary Calcium Scan Coronary Calcium Scan Also known as Calcium Scan Test A coronary calcium scan is a CT scan of your heart that detects and measures the amount of calcium in the walls of your coronary arteries. Overview ...

  15. Calcium source (image) (United States)

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

  16. Calcium and bones (image) (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 ...

  17. Calcium hydroxide poisoning (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 ...

  18. Calcium Pyrophosphate Deposition (CPPD) (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 ...

  19. Calcium blood test (United States)

    ... page: // Calcium blood test To use the sharing features on this page, please enable JavaScript. The calcium blood test measures the level of calcium in the blood. ...

  20. Calcium Impact on Milk Gels Formation

    DEFF Research Database (Denmark)

    Koutina, Glykeria

    salts. The perturbation of calcium equilibria by these factors will affect the final properties of acid, calcium and rennet milk gels. By decreasing the pH from 6.0 to 5.2 (acid gels), the calcium equilibrium was significantly affected by temperature (4, 20, 30, 40 oC), and different combinations...... of temperature and pH may result in different final structure properties in dairy products such as cheese. A significant amount of calcium remained in the micelles between pH 4.8 and 4.6, this can contribute to the final strength of acid milk gels, such as in yogurt or in cream cheeses. After the gelation point......, a sudden solubilization of micellar calcium was observed at 50 oC and 60 oC, which revealed an interesting role of calcium during acidification at elevated temperatures. After enrichment of milk with calcium D-lactobionate, the added calcium was distributed between the micellar and serum milk phase at pH 6...

  1. Calcium absorption from fortified ice cream formulations compared with calcium absorption from milk. (United States)

    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


    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-fortified ice cream formulation that is lower in fat than regular ice cream and could provide a useful source of additional dietary calcium. Calcium absorption from two different ice cream formulations was determined in young adults and compared with milk. Sixteen healthy volunteers (25 to 45 years of age), recruited from the general public of The Netherlands, participated in a randomized, reference-controlled, double-blind cross-over study in which two test products and milk were consumed with a light standard breakfast on three separate occasions: a standard portion of ice cream (60 g) fortified with milk minerals and containing a low level (3%) of butter fat, ice cream (60 g) fortified with milk minerals and containing a typical level (9%) of coconut oil, and reduced-fat milk (1.7% milk fat) (200 mL). Calcium absorption was measured by the dual-label stable isotope technique. Effects on calcium absorption were evaluated by analysis of variance. Fractional absorption of calcium from the 3% butterfat ice cream, 9% coconut oil ice cream, and milk was 26%+/-8%, 28%+/-5%, and 31%+/-9%, respectively, and did not differ significantly (P=0.159). Results indicate that calcium bioavailability in the two calcium-fortified ice cream formulations used in this study is as high as milk, indicating that ice cream may be a good vehicle for delivery of calcium.

  2. Substitutions in Calcium Aluminates and Calcium Aluminoferrites. (United States)


  3. Can total cardiac calcium predict the coronary calcium score? (United States)

    Pressman, Gregg S; Crudu, Vitalie; Parameswaran-Chandrika, Anoop; Romero-Corral, Abel; Purushottam, Bhaskar; Figueredo, Vincent M


    Mitral annular calcification (MAC) shares the same risk factors as atherosclerosis and is associated with coronary artery disease as well as cardiovascular events. However, sensitivity and positive predictive value are low. We hypothesized that a global echocardiographic calcium score would better predict coronary atherosclerotic burden, as assessed by coronary artery calcium score (CAC), than MAC alone. An echocardiographic score was devised to measure global cardiac calcification in a semi-quantitative manner; this included calcification in the aortic valve and root, the mitral valve and annulus, and the sub-mitral apparatus. This score, and a simplified version, were compared with a similar calcification score by CT scan, as well as the CAC. There was a good correlation between the two global calcification scores; the echocardiographic score also correlated with CAC. Using CAC >400 as a measure of severe coronary atherosclerosis, an echocardiographic score ≥5 had a positive predictive value of 60%. Importantly, the simplified score performed equally well (≥3 had a positive predictive value of 62%). Global cardiac calcification, assessed by CT scan or echocardiography, correlates with the extent of coronary calcium. A semi-quantitative calcium score can be easily applied during routine echocardiographic interpretation and can alert the reader to the possibility of severe coronary atherosclerosis. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

  4. Calcium channel blocker overdose (United States)

    ... page: // Calcium-channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium-channel blockers are a type of medicine used to ...

  5. Fenoprofen calcium overdose (United States)

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

  6. Calcium signaling in lymphocytes and ELF fields. Evidence for an electric field metric and a site of interaction involving the calcium ion channel. (United States)

    Liburdy, R P


    Calcium influx increased during mitogen-activated signal transduction in thymic lymphocytes exposed to a 22 mT, 60 Hz magnetic field (E induced = 1.7 mV/cm, 37 degrees C, 60 min). To distinguish between an electric or a magnetic field dependence a special multi-ring annular cell culture plate based on Faraday's Law of Induction was employed. Studies show a dependence on the strength of the induced electric field at constant magnetic flux density. Moreover, exposure to a pure 60 Hz electric field or to a magnetically-induced electric field of identical strength resulted in similar changes in calcium transport. The first real-time monitoring of [Ca2+]i during application of a 60 Hz electric field revealed an increase in [Ca2+]i observed 100 s after mitogen stimulation; this suggests that the plateau phase rather than the early phase of calcium signaling was influenced. The hypothesis was tested by separating, in time, the early release of calcium from intracellular stores from the influx of extracellular calcium. In calcium-free buffer, 60 Hz field exerted little influence on the early release of calcium from intracellular stores. In contrast, addition of extracellular calcium during exposure enhanced calcium influx through the plasma membrane. Alteration of the plateau phase of calcium signaling implicates the calcium channel as a site of field interaction. In addition, an electric field exposure metric is mechanistically consistent with a cell-surface interaction site.

  7. Calcium and Mitosis (United States)

    Hepler, P.


    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.

  8. Calcium en cardioplegie

    NARCIS (Netherlands)

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


    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

  9. Evaluation of pH and calcium ion diffusion from calcium hydroxide pastes and MTA. (United States)

    Sáez, María Del M; López, Gabriela L; Atlas, Diana; de la Casa, María L


    The aim of this ex vivo study was to evaluate changes in pH and calcium ion diffusion through root dentin from calcium hydroxide (Ca (OH) 2) and mineral trioxide aggregate (MTA) pastes at 7, 30 and 60 days; and the relationship between pH and ion diffusion. Thirty-two human premolars were used. Crowns were sectioned and root canals instrumented and filled in with the following preparations: 1) Ca(OH) 2 + distilled water (n=7); 2) Ca(OH) 2 + 0.1% chlorhexidine gluconate (n=7); 3) MTA + distilled water (n=7); 4) MTA + 0.1% chlorhexidine gluconate (CHX) (n=7); 5) distilled water (n=2) (control); 6) 0.1% chlorhexidine gluconate (n=2) (control). The apex and coronary opening were sealed with IRM. Roots were placed in Eppendorf tubes with 1 ml distilled water at 37°C and 100% humidity. At baseline, 7, 30 and 60 days, pH was measured with pH meter, and calcium ion content in the solution was analyzed by atomic absorption spectrophotometry. The data were statistically analyzed using ANOVA, simple linear regression analysis and Pearson's correlation test. The highest pH values were achieved with calcium hydroxide pastes at 60 days (p ≤ 0.05). Calcium ions were released in all groups. The calcium hydroxide paste with distilled water at 60 days had the highest calcium ion value (p ≤ 0.01). There was a positive correlation between calcium and pH values. Sociedad Argentina de Investigación Odontológica.

  10. Clonorcis sinensis eggs are associated with calcium carbonate gallbladder stones. (United States)

    Qiao, Tie; Ma, Rui-hong; Luo, Zhen-liang; Yang, Liu-qing; Luo, Xiao-bing; Zheng, Pei-ming


    Calcium carbonate gallbladder stones were easily neglected because they were previously reported as a rare stone type in adults. The aim of this study was to investigate the relationship between calcium carbonate stones and Clonorchis sinensis infection. A total of 598 gallbladder stones were studied. The stone types were identified by FTIR spectroscopy. The C. sinensis eggs and DNA were detected by microscopic examination and real-time fluorescent PCR respectively. And then, some egg-positive stones were randomly selected for further SEM examination. Corresponding clinical characteristics of patients with different types of stones were also statistically analyzed. The detection rate of C. sinensis eggs in calcium carbonate stone, pigment stone, mixed stone and cholesterol stone types, as well as other stone types was 60%, 44%, 36%, 6% and 30%, respectively, which was highest in calcium carbonate stone yet lowest in cholesterol stone. A total of 182 stones were egg-positive, 67 (37%) of which were calcium carbonate stones. The C. sinensis eggs were found adherent to calcium carbonate crystals by both light microscopy and scanning electron microscopy. Patients with calcium carbonate stones were mainly male between the ages of 30 and 60, the CO2 combining power of patients with calcium carbonate stones were higher than those with cholesterol stones. Calcium carbonate gallbladder stones are not rare, the formation of which may be associated with C. sinensis infection. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Calcium channel blocker poisoning

    Directory of Open Access Journals (Sweden)

    Miran Brvar


    Full Text Available Background: Calcium channel blockers act at L-type calcium channels in cardiac and vascular smooth muscles by preventing calcium influx into cells with resultant decrease in vascular tone and cardiac inotropy, chronotropy and dromotropy. Poisoning with calcium channel blockers results in reduced cardiac output, bradycardia, atrioventricular block, hypotension and shock. The findings of hypotension and bradycardia should suggest poisoning with calcium channel blockers.Conclusions: Treatment includes immediate gastric lavage and whole-bowel irrigation in case of ingestion of sustainedrelease products. All patients should receive an activated charcoal orally. Specific treatment includes calcium, glucagone and insulin, which proved especially useful in shocked patients. Supportive care including the use of catecholamines is not always effective. In the setting of failure of pharmacological therapy transvenous pacing, balloon pump and cardiopulmonary by-pass may be necessary.

  12. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

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


    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 inhibi...

  13. Calcium and bones (United States)

    ... eat in their diet. Vitamin D is the hormone that helps the gut absorb more calcium. Many older adults have common risks that make bone health worse. Calcium intake in the diet (milk, cheese, yogurt) is low. Vitamin D levels are ...

  14. Calcium D-saccharate

    DEFF Research Database (Denmark)

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


    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...

  15. Extracellular Calcium and Magnesium

    African Journals Online (AJOL)

    ABSTRACT. The cause of preeclampsia remains unknown and calcium and magnesium supplement are being suggested as means of prevention. The objective of this study was to assess magnesium and calcium in the plasma and cerebrospinal fluid of Nigerian women with preedamp sia and eclampsia. Setting was ...

  16. Chemical analysis of the liberation of calcium and hydroxyl ions from calcium hydroxide pastes in connective tissue in the dog--Part I. (United States)

    Estrela, C; Pesce, H F


    The objective of this research is to chemically analyze calcium hydroxide pastes added to three hydrosoluble vehicles having different acid-base characteristics using polyethylene tubes implanted in subcutaneous connective tissue in a dog, evaluating the liberation of calcium and hydroxyl ions over a period of 7, 30, 45 and 60 days. The three vehicles were saline, anesthetic, and polyethylene glycol 400. Chemical analysis of the liberated calcium ions was done by means of conductimetry using EDTA for titration. Liberation of hydroxyl ions was determined by analogy of calcium ions liberated, which are in direct proportion to the molecular weight of calcium hydroxide.

  17. Cadmium induces transcription independently of intracellular calcium mobilization.

    Directory of Open Access Journals (Sweden)

    Brooke E Tvermoes

    Full Text Available BACKGROUND: Exposure to cadmium is associated with human pathologies and altered gene expression. The molecular mechanisms by which cadmium affects transcription remain unclear. It has been proposed that cadmium activates transcription by altering intracellular calcium concentration ([Ca(2+](i and disrupting calcium-mediated intracellular signaling processes. This hypothesis is based on several studies that may be technically problematic; including the use of BAPTA chelators, BAPTA-based fluorescent sensors, and cytotoxic concentrations of metal. METHODOLOGY/PRINCIPAL FINDING: In the present report, the effects of cadmium on [Ca(2+](i under non-cytotoxic and cytotoxic conditions was monitored using the protein-based calcium sensor yellow cameleon (YC3.60, which was stably expressed in HEK293 cells. In HEK293 constitutively expressing YC3.60, this calcium sensor was found to be insensitive to cadmium. Exposing HEK293::YC3.60 cells to non-cytotoxic cadmium concentrations was sufficient to induce transcription of cadmium-responsive genes but did not affect [Ca(2+](i mobilization or increase steady-state mRNA levels of calcium-responsive genes. In contrast, exposure to cytotoxic concentrations of cadmium significantly reduced intracellular calcium stores and altered calcium-responsive gene expression. CONCLUSIONS/SIGNIFICANCE: These data indicate that at low levels, cadmium induces transcription independently of intracellular calcium mobilization. The results also support a model whereby cytotoxic levels of cadmium activate calcium-responsive transcription as a general response to metal-induced intracellular damage and not via a specific mechanism. Thus, the modulation of intracellular calcium may not be a primary mechanism by which cadmium regulates transcription.


    NARCIS (Netherlands)



    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

  19. Calcium sensing in exocytosis

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Wu, Bingbing; Han, Weiping


    Neurotransmitters, neuropeptides and hormones are released through regulated exocytosis of synaptic vesicles and large dense core vesicles. This complex and highly regulated process is orchestrated by SNAREs and their associated proteins. The triggering signal for regulated exocytosis is usually...... an increase in intracellular calcium levels. Besides the triggering role, calcium signaling modulates the precise amount and kinetics of vesicle release. Thus, it is a central question to understand the molecular machineries responsible for calcium sensing in exocytosis. Here we provide an overview of our...

  20. Kinetics of calcium binding to dental biofilm bacteria. (United States)

    Leitão, Tarcísio Jorge; Cury, Jaime Aparecido; Tenuta, Livia Maria Andaló


    Dental biofilm bacteria can bind calcium ions and release them during a pH drop, which could decrease the driving force for dental demineralization (i.e. hydroxyapatite dissolution) occurring at reduced pHs. However, the kinetics of this binding and release is not completely understood. Here we validated a method to evaluate the kinetics of calcium binding and release to/from Streptococcus mutans, and estimated the importance of this reservoir as a source of ions. The kinetics of calcium binding was assessed by measuring the amount of bound calcium in S. mutans Ingbrit 1600 pellets treated with PIPES buffer, pH 7.0, containing 1 or 10 mM Ca; for the release kinetics, bacterial pellets previously treated with 1 mM or 10 mM Ca were exposed to the calcium-free or 1 mM Ca PIPES buffer, pH 7.0, for up to 60 min. Binding and release curves were constructed and parameters of kinetics were calculated. Also, calcium release was assessed by exposing pellets previously treated with calcium to a pH 5.0 buffer for 10 min. Calcium binding to bacteria was concentration-dependent and rapid, with maximum binding reached at 5 min. On the other hand, calcium release was slower, and according to the calculations, would never be complete in the groups pretreated with 10 mM Ca. Decreasing pH from 7.0 to 5.0 caused a release of calcium able to increase the surrounding fluid calcium concentration in 2 mM. The results suggest that dental biofilm bacteria may act as a calcium reservoir, rapidly binding ions from surrounding fluids, releasing them slowly at neutral pH and promptly during a pH drop.

  1. Bone repair in calcium-deficient rats: comparison of xylitol+calcium carbonate with calcium carbonate, calcium lactate and calcium citrate on the repletion of calcium. (United States)

    Hämäläinen, M M


    The potential value of xylitol in calcium therapy was evaluated by comparing the effect of dietary xylitol (50 g/kg diet) + calcium carbonate with the effects of calcium carbonate, calcium lactate and calcium citrate on bone repair of young male rats after the rats consumed for 3 wk a calcium-deficient diet (0.2 g Ca/kg diet). After this calcium-depletion period, the rats were fed for 2 wk one of four diets, each containing 5 g Ca/kg diet as one of the four dietary calcium sources. The diet of the control animals was supplemented with CaCO3 (5 g Ca/kg diet) throughout the study. The Ca-deficient rats showed low bone mass, low serum calcium and high serum 1,25-dihydroxycholecalciferol, parathyroid hormone (1-34 fraction) and osteocalcin concentrations. They also excreted magnesium, phosphate and hydroxyproline in the urine in high concentrations, and had high bone alkaline phosphatase and tartrate-resistant acid phosphatase activities. Most of these changes were reversed by the administered of the calcium salts. The highest recoveries of femoral dry weight, calcium, magnesium and phosphate were observed in the groups receiving xylitol+CaCO3 and calcium lactate. Calcium lactate and calcium citrate caused low serum phosphate concentration compared with rats receiving CaCO3 and with the age-matched Ca-replete controls. Xylitol-treated rats excreted more calcium and magnesium in urine than did the other rats, probably due to increased absorption of these minerals from the gut. These results suggest that dietary xylitol improves the bioavailability of calcium salts.

  2. Effects of elevated calcium on motor and exploratory activities of rats

    Directory of Open Access Journals (Sweden)

    Godinho A.F.


    Full Text Available The effects of serum and brain calcium concentration on rat behavior were tested by maintaining animals on either distilled water (N = 60 or water containing 1% calcium gluconate (N = 60 for 3 days. Animals that were maintained on high calcium drinking water presented increased serum calcium levels (control = 10.12 ± 0.46 vs calcium treated = 11.62 ± 0.51 µg/dl. Increase of brain calcium levels was not statistically significant. In the behavioral experiments each rat was used for only one test. Rats that were maintained on high calcium drinking water showed increased open-field behavior of ambulation (20.68% and rearing (64.57%. On the hole-board, calcium-supplemented animals showed increased head-dip (67% and head-dipping (126%, suggesting increased ambulatory and exploratory behavior. The time of social interaction was normal in animals maintained on drinking water containing added calcium. Rats supplemented with calcium and submitted to elevated plus-maze tests showed a normal status of anxiety and elevated locomotor activity. We conclude that elevated levels of calcium enhance motor and exploratory behavior of rats without inducing other behavioral alterations. These data suggest the need for a more detailed analysis of several current proposals for the use of calcium therapy in humans, for example in altered blood pressure states, bone mineral metabolism disorders in the elderly, hypocalcemic states, and athletic activities.

  3. Calcium – how and why?

    Indian Academy of Sciences (India)


    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 ...

  4. Calcium and Your Child (United States)

    ... Milk Allergy Figuring Out Food Labels What's a Vegetarian? Osteoporosis Minerals Your Bones Mineral Chart Vitamin D ... Need to Drink Milk? Lactose Intolerance Becoming a Vegetarian Soy Foods and Health Calcium Bones, Muscles, and ...

  5. Stoichiometry of Calcium Medicines (United States)

    Pinto, Gabriel


    The topic of calcium supplement and its effects on human lives is presented in the way of questions to the students. It enables the students to realize the relevance of chemistry outside the classroom surrounding.

  6. Magnesium, calcium and cancer

    National Research Council Canada - National Science Library

    Anghileri, Leopoldo J


    Magnesium ion (Mg(2+)) and calcium ion (Ca(2+)) control a diverse and important range of cellular processes, such as gene transcription, cell proliferation, neoplastic transformation, immune response and therapeutic treatment...

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

    DEFF Research Database (Denmark)

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


    The physiological significance and subcellular distribution of voltage dependent calcium channels was defined using calcium channel blockers to inhibit potassium induced rises in cytosolic calcium concentration in cultured mouse neocortical neurons. The cytosolic calcium concentration was measured...... channels were differentially distributed in somata, neurites and nerve terminals. omega-conotoxin MVIIC (omega-CgTx MVIIC) inhibited approximately 40% of the Ca(2+)-rise in both somata and neurites and 60% of the potassium induced [3H]GABA release, indicating that the Q-type channel is the quantitatively...... using the fluorescent calcium chelator fura-2. The types of calcium channels present at the synaptic terminal were determined by the inhibitory action of calcium channel blockers on potassium-induced [3H]GABA release in the same cell preparation. L-, N-, P-, Q- and R-/T-type voltage dependent calcium...

  8. [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.


    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

  9. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau


    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

  10. [Microbial geochemical calcium cycle]. (United States)

    Zavarzin, G A


    The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO2 from the atmosphere. The major part of calcium deposits was formed in the Precambrian, when prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g., cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rock predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is exposed by stromatolites, which are the most common organo-sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO2 does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the "soda continent", which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca2+. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial community, which was a precursor of stromatolites.

  11. Calcium orthophosphates in dentistry. (United States)

    Dorozhkin, Sergey V


    Dental caries, also known as tooth decay or a cavity, remains a major public health problem in the most communities even though the prevalence of disease has decreased since the introduction of fluorides for dental care. Therefore, biomaterials to fill dental defects appear to be necessary to fulfill customers' needs regarding the properties and the processing of the products. Bioceramics and glass-ceramics are widely used for these purposes, as dental inlays, onlays, veneers, crowns or bridges. Calcium orthophosphates belong to bioceramics but they have some specific advantages over other types of bioceramics due to a chemical similarity to the inorganic part of both human and mammalian bones and teeth. Therefore, calcium orthophosphates (both alone and as components of various formulations) are used in dentistry as both dental fillers and implantable scaffolds. This review provides brief information on calcium orthophosphates and describes in details current state-of-the-art on their applications in dentistry and dentistry-related fields. Among the recognized dental specialties, calcium orthophosphates are most frequently used in periodontics; however, the majority of the publications on calcium orthophosphates in dentistry are devoted to unspecified "dental" fields.

  12. Discovery and Development of Calcium Channel Blockers

    Directory of Open Access Journals (Sweden)

    Théophile Godfraind


    Full Text Available In the mid 1960s, experimental work on molecules under screening as coronary dilators allowed the discovery of the mechanism of calcium entry blockade by drugs later named calcium channel blockers. This paper summarizes scientific research on these small molecules interacting directly with L-type voltage-operated calcium channels. It also reports on experimental approaches translated into understanding of their therapeutic actions. The importance of calcium in muscle contraction was discovered by Sidney Ringer who reported this fact in 1883. Interest in the intracellular role of calcium arose 60 years later out of Kamada (Japan and Heibrunn (USA experiments in the early 1940s. Studies on pharmacology of calcium function were initiated in the mid 1960s and their therapeutic applications globally occurred in the the 1980s. The first part of this report deals with basic pharmacology in the cardiovascular system particularly in isolated arteries. In the section entitled from calcium antagonists to calcium channel blockers, it is recalled that drugs of a series of diphenylpiperazines screened in vivo on coronary bed precontracted by angiotensin were initially named calcium antagonists on the basis of their effect in depolarized arteries contracted by calcium. Studies on arteries contracted by catecholamines showed that the vasorelaxation resulted from blockade of calcium entry. Radiochemical and electrophysiological studies performed with dihydropyridines allowed their cellular targets to be identified with L-type voltage-operated calcium channels. The modulated receptor theory helped the understanding of their variation in affinity dependent on arterial cell membrane potential and promoted the terminology calcium channel blocker (CCB of which the various chemical families are introduced in the paper. In the section entitled tissue selectivity of CCBs, it is shown that characteristics of the drug, properties of the tissue, and of the stimuli are

  13. Calcium Signalling: Fishing Out Molecules of Mitochondrial Calcium Transport


    Hajnóczky, György; Csordás, György


    Cellular energy metabolism, survival and death are controlled by mitochondrial calcium signals originating in the cytoplasm. Now, RNAi studies link three proteins — MICU1, NCLX and LETM1 — to the previously unknown molecular mechanism of mitochondrial calcium transport.

  14. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate. (United States)

    Henrickson, Charles H.; Robinson, Paul R.


    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)

  15. Reductions in calcium uptake induced in rat brain synaptosomes by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kandasamy, S.B.; Howerton, T.C.; Hunt, W.A. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))


    Gamma irradiation (60Co) reduced KCl-stimulated voltage-dependent 45Ca2+ uptake in whole-brain, cortical, and striatal synaptosomes. The time course (3, 10, 30, and 60 s) of calcium uptake by irradiated (3 Gy) and nonirradiated synaptosomes, as well as the effect of KCl (15-65 mM), was measured in whole-brain synaptosomes. The fastest and highest rate of depolarization-dependent calcium uptake occurred at 3 s with 65 mM KCl. Irradiation reduced calcium uptake at all incubation times and KCl concentrations. Bay K 8644 enhancement of KCl-stimulated calcium influx was also reduced by radiation exposure. Nimodipine binding to dihydropyridine (DHP) L-type calcium channel receptors was not altered following radiation exposure. These results demonstrate an inhibitory effect of ionizing radiation on the voltage-sensitive calcium channels in rat brain synaptosomes that are not mediated by DHP receptors.

  16. Plasma phospholipid arachidonic acid content and calcium metabolism in idiopathic calcium nephrolithiasis. (United States)

    Baggio, B; Budakovic, A; Nassuato, M A; Vezzoli, G; Manzato, E; Luisetto, G; Zaninotto, M


    Reports of an increase in plasma and erythrocyte phospholipid arachidonic acid content and in urinary prostaglandin E2 (PGE2) excretion in patients with idiopathic calcium nephrolithiasis suggested their crucial role in the pathogenesis of hypercalciuria, a well-known risk factor for lithogenesis. To confirm this hypothesis, 15 healthy subjects and 20 nephrolithiasis patients were evaluated for plasma phospholipid polyunsaturated fatty acid content and PGE2 concentration, serum parathyroid hormone, 25 hydroxyvitamin D3, 1, 25-dihydroxyvitamin D3, and bone-specific alkaline phosphatase levels, as well as urinary excretion of calcium, biochemical markers of bone resorption (hydroxyproline and crossLaps), and intestinal calcium absorption. Furthermore, the effect of a 30-day fish-oil diet supplementation on the previously mentioned parameters was investigated in the patients. At baseline, patients compared with controls showed higher levels of plasma phospholipid arachidonic acid content (P = 0.002), PGE2 (P = 0.0004), serum 25-vitamin D3 (P = 0.001), and 1,25-vitamin D3 (P = 0.001), urinary excretion of calcium (P = 0.001), hydroxyproline (P = 0.007), and crossLaps (P = 0.019), as well as intestinal calcium absorption (P = 0.03 at 60 min). Fish oil supplementation induced a reduction in the plasma phospholipid arachidonic acid level (P < 0.0001), and except for serum concentrations of 25-vitamin D3, normalized baseline blood and urinary parameters, including intestinal calcium absorption. A close correlation between plasma PGE2 and serum 1,25-vitamin D3 (P = 0.004) and between phospholipid arachidonic acid and intestinal calcium absorption (P = 0.0002) and calciuria (P = 0.007) was observed, as well as between urine excretion of crossLaps and hydroxyproline (P < 0.0001), crossLaps and calcium (P < 0.0001), and hydroxyproline and calcium (P < 0.0001). These findings indicate that the phospholipid arachidonic acid content anomaly could represent the primary event

  17. Children's Bone Health and Calcium (United States)

    ... Email Share Dialog × Print Children's Bone Health and Calcium: Condition Information What is bone health and how ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

  18. Interstellar C60+


    Berne, Olivier; Mulas, Giacomo; Joblin, Christine


    Buckminsterfullerene (C60) was recently detected through its infrared emission bands in the interstellar medium (ISM), including in the proximity of massive stars, where physical conditions could favor the formation of the cationic form, C60+. In addition, C60+ was proposed as the carrier of two diffuse interstellar bands in the near-IR, although a firm identification still awaits for gas-phase spectroscopic data. We examined in details the Spitzer IRS spectra of the NGC 7023 reflection nebul...

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

    DEFF Research Database (Denmark)

    Timmermann, D B; Lund, T M; Belhage, B


    using the fluorescent calcium chelator fura-2. The types of calcium channels present at the synaptic terminal were determined by the inhibitory action of calcium channel blockers on potassium-induced [3H]GABA release in the same cell preparation. L-, N-, P-, Q- and R-/T-type voltage dependent calcium...... channels were differentially distributed in somata, neurites and nerve terminals. omega-conotoxin MVIIC (omega-CgTx MVIIC) inhibited approximately 40% of the Ca(2+)-rise in both somata and neurites and 60% of the potassium induced [3H]GABA release, indicating that the Q-type channel is the quantitatively...... in cytosolic calcium concentration. The results of this investigation demonstrate that pharmacologically distinct types of voltage dependent calcium channels are differentially localized in cell bodies, neurites and nerve terminals of mouse cortical neurons but that the Q-type calcium channel appears...

  20. Stable prenucleation calcium carbonate clusters


    Gebauer, Denis; Völkel, Antje; Cölfen, Helmut


    Calcium carbonate forms scales, geological deposits, biominerals, and ocean sediments. Huge amounts of carbon dioxide are retained as carbonate ions, and calcium ions represent a major contribution to water hardness. Despite its relevance, little is known about the precipitation mechanism of calcium carbonate, and specified complex crystal structures challenge the classical view on nucleation considering the formation of metastable ion clusters. We demonstrate that dissolved calcium carbonate...

  1. Assay for calcium channels

    Energy Technology Data Exchange (ETDEWEB)

    Glossmann, H.; Ferry, D.R.


    This chapter focuses on biochemical assays for Ca/sup 2 +/-selective channels in electrically excitable membranes which are blocked in electrophysiological and pharmacological experiments by verapamil, 1,4-dihydropyridines, diltiazen (and various other drugs), as well as inorganic di- or trivalent cations. The strategy employed is to use radiolabeled 1,4-dihydropyridine derivatives which block calcium channels with ED/sub 50/ values in the nanomolar range. Although tritiated d-cis-diltiazem and verapamil can be used to label calcium channels, the 1,4-dihydropyridines offer numerous advantages. The various sections cover tissue specificity of channel labeling, the complex interactions of divalent cations with the (/sup 3/H)nimodipine-labeled calcium channels, and the allosteric regulation of (/sup 3/H)nimodipine binding by the optically pure enantiomers of phenylalkylamine and benzothiazepine calcium channel blockers. A comparison of the properties of different tritiated 1,4-dihydropyridine radioligands and the iodinated channel probe (/sup 125/I)iodipine is given.

  2. Solar Imagery - Chromosphere - Calcium (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 500...

  3. The Plasma Membrane Calcium Pump (United States)

    Rasmussen, H.


    Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.

  4. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

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


    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...

  5. Impregnating Coal With Calcium Carbonate (United States)

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


    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.

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

    Directory of Open Access Journals (Sweden)

    Nanik Zubaidah


    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.

  7. Calcium signaling in taste cells. (United States)

    Medler, Kathryn F


    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. This article is part of a Special Issue entitled: 13th European Symposium on Calcium. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Importance of citrate and the calcium : citrate ratio in patients with calcium renal lithiasis and severe lithogenesis. (United States)

    Arrabal-Polo, Miguel Angel; Arrabal-Martin, Miguel; Arias-Santiago, Salvador; Garrido-Gomez, Juan; Poyatos-Andujar, Antonio; Zuluaga-Gomez, Armando


    Different studies have shown the importance of citrate in the formation of calcium stones. It has further been shown that the states of metabolic acidosis result in an increase in bone resorption and lower urinary citrate levels. Increasing the intake of citrate in these patients can reduce the lithogenic risk and improve bone mineral density (BMD), contributing to control of both diseases. The study shows the importance of citrate in patients with calcium stones and BMD loss. The deficit in citrate excretion is associated with a decrease in bone mineralization and increased β-crosslaps. A calcium : citrate ratio >0.25 in patients with calcium stones and loss of mineral density may predict severe lithogenic activity. To analyse the importance of urinary citrate and the urinary calcium : citrate ratio in patients with calcium renal lithiasis and severe lithogenesis compared with a control group of patients without lithiasis. A cross-sectional study of 115 patients in eastern Andalusia, Spain was conducted. The patients were divided into two groups: Group A: 56 patients aged 25-60 years without calcium renal lithiasis; Group B: 59 patients aged 25-60 years, presenting with calcium renal lithiasis and severe lithogenesis. The citrate levels and the calcium : citrate ratio in the patients' urine and the relationship of these two factors to lithiasic activity were analysed and compared. In Group B, 32.2% of the patients presented with hypocitraturia, compared with 14.3% of the patients in Group A (P = 0.02). The urinary citrate levels were lower in Group B than in Group A (P = 0.001) and the calcium : citrate ratio was higher in Group B than in Group A (P = 0.005). The results suggest that a patient urinary calcium : citrate ratio > 0.25 indicates severe lithogenesis (with a sensitivity of 89% and a specificity of 57%). After linear regression analysis, we found that the urinary citrate level is an independent factor associated with the changes in bone densitometry T

  9. Organoaqueous calcium chloride electrolytes for capacitive charge storage in carbon nanotubes at sub-zero-temperatures. (United States)

    Gao, Yun; Qin, Zhanbin; Guan, Li; Wang, Xiaomian; Chen, George Z


    Solutions of calcium chloride in mixed water and formamide are excellent electrolytes for capacitive charge storage in partially oxidised carbon nanotubes at unprecedented sub-zero-temperatures (e.g. 67% capacitance retention at -60 °C).

  10. Annual Feedback Is an Effective Tool for a Sustained Increase in Calcium Intake among Older Women

    Directory of Open Access Journals (Sweden)

    Geoffrey C. Nicholson


    Full Text Available We aimed to optimize calcium intake among the 2,000+ older women taking part in the Vital D study. Calcium supplementation was not included in the study protocol. Our hypothesis was that annual feedback of calcium intake and informing women of strategies to improve calcium intake can lead to a sustained increase in the proportion of women who consume adequate levels of the mineral. Calcium intake was assessed on an annual basis using a validated short food frequency questionnaire (FFQ. Supplemental calcium intake was added to the dietary estimate. Participants and their nominated doctor were sent a letter that the participant’s estimated daily calcium intake was adequate or inadequate based on a cutoff threshold of 800 mg/day. General brief statements outlining the importance of an adequate calcium intake and bone health were included in all letters. At baseline, the median daily consumption of calcium was 980 mg/day and 67 percent of 1,951 participants had calcium intake of at least 800 mg per day. Of the 644 older women advised of an inadequate calcium intake at baseline (< 800 mg/day, 386 (60% had increased their intake by at least 100 mg/day when re-assessed twelve months later. This desirable change was sustained at 24 months after baseline with almost half of these women (303/644 consuming over 800 mg calcium per day. This study devised an efficient method to provide feedback on calcium intake to over 2,000 older women. The improvements were modest but significant and most apparent in those with a low intake at baseline. The decreased proportion of these women with an inadequate intake of calcium 12- and 24-months later, suggests this might be a practical, low cost strategy to maintain an adequate calcium intake among older women.


    Barton, J.


    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.

  12. Calcium metabolism and cardiovascular function after spaceflight (United States)

    Hatton, Daniel C.; Yue, Qi; Dierickx, Jacqueline; Roullet, Chantal; Otsuka, Keiichi; Watanabe, Mitsuaki; Coste, Sarah; Roullet, Jean Baptiste; Phanouvang, Thongchan; Orwoll, Eric; hide


    To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P platelet free calcium (intracellular calcium concentration) were also reduced (P metabolism (P metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.

  13. Wolfhard Janke turns 60


    Editorial Board


    On December 11th, 2015, Wolfhard Janke, a member of the Editorial Board of ``Condensed Matter Physics'' and a leading expert in computer simulations in condensed matter physics, celebrated his 60th birthday.

  14. Models of calcium signalling

    CERN Document Server

    Dupont, Geneviève; Kirk, Vivien; Sneyd, James


    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...

  15. Reducing Severity of Late Blight (Phytophthora infestans and Improving Potato (Solanum tuberosum L. Tuber Yield with Pre-Harvest Application of Calcium Nutrients

    Directory of Open Access Journals (Sweden)

    Yewubnesh Wendimu Seifu


    Full Text Available The efficiency of pre-harvest application of calcium chloride alone, calcium nitrate alone, and combined application of calcium chloride and calcium nitrate (1:1 was evaluated in reducing the severity of P. infestans and improving potato tuber yield. Pot experiment was conducted in randomized complete block design with four replications. The treatments consisted of combination of two potato varieties (Shenkola and Gera and three types of calcium nutrients (calcium chloride alone, calcium nitrate alone, and calcium chloride mixed with calcium nitrate, each at three levels (5, 10, and 15 g per liter per plant and the control treatment (0 g of calcium nutrients. In comparison to the control treatment, the application of calcium nutrients significantly decreased the severity of late blight disease and improved potato tuber yield. The effect of calcium nutrients on the severity of late blight disease and potato tuber yield differed among the two potato varieties. The maximum severity reduction (60% was noticed in the Gera potato variety with the application of calcium chloride mixed with calcium nitrate (1:1, supplied at 15 g per plant. However, the highest average tuber yield was obtained with the application of calcium nitrate at 15 g per plant, and average tuber yield was increased by 77% in both potato varieties. Hence, foliar application of either calcium nitrate alone or calcium nitrate mixed with calcium chloride was found to be more efficient than the application of calcium chloride alone. This result suggests that the nitrate ion present in the calcium nitrate may make a difference in terms of reducing the severity of late blight disease and improving potato tuber yield. The lowered severity of late blight disease and the increased tuber yield in potato plants sprayed with calcium nutrients may be because of the higher accumulation of calcium in the plant tissue.

  16. Elemental calcium intake associated with calcium acetate/calcium carbonate in the treatment of hyperphosphatemia. (United States)

    Wilson, Rosamund J; Copley, J Brian


    Calcium-based and non-calcium-based phosphate binders have similar efficacy in the treatment of hyperphosphatemia; however, calcium-based binders may be associated with hypercalcemia, vascular calcification, and adynamic bone disease. A post hoc analysis was carried out of data from a 16-week, Phase IV study of patients with end-stage renal disease (ESRD) who switched to lanthanum carbonate monotherapy from baseline calcium acetate/calcium carbonate monotherapy. Of the intent-to-treat population (N=2520), 752 patients with recorded dose data for calcium acetate (n=551)/calcium carbonate (n=201) at baseline and lanthanum carbonate at week 16 were studied. Elemental calcium intake, serum phosphate, corrected serum calcium, and serum intact parathyroid hormone levels were analyzed. Of the 551 patients with calcium acetate dose data, 271 (49.2%) had an elemental calcium intake of at least 1.5 g/day at baseline, and 142 (25.8%) had an intake of at least 2.0 g/day. Mean (95% confidence interval [CI]) serum phosphate levels were 6.1 (5.89, 6.21) mg/dL at baseline and 6.2 (6.04, 6.38) mg/dL at 16 weeks; mean (95% CI) corrected serum calcium levels were 9.3 (9.16, 9.44) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Of the 201 patients with calcium carbonate dose data, 117 (58.2%) had an elemental calcium intake of at least 1.5 g/day, and 76 (37.8%) had an intake of at least 2.0 g/day. Mean (95% CI) serum phosphate levels were 5.8 (5.52, 6.06) mg/dL at baseline and 5.8 (5.53, 6.05) mg/dL at week 16; mean (95% CI) corrected serum calcium levels were 9.7 (9.15, 10.25) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Calcium acetate/calcium carbonate phosphate binders, taken to control serum phosphate levels, may result in high levels of elemental calcium intake. This may lead to complications related to calcium balance.

  17. First Quantification of Calcium Intake from Calcium-Dense Dairy Products in Dutch Fracture Patients (The Delft Cohort Study

    Directory of Open Access Journals (Sweden)

    Peter van den Berg


    Full Text Available Recommendations for daily calcium intake from dairy products are variable and based on local consensus. To investigate whether patients with a recent fracture complied with these recommendations, we quantified the daily dairy calcium intake including milk, milk drinks, pudding, yoghurt, and cheese in a Dutch cohort of fracture patients and compared outcomes with recent data of a healthy U.S. cohort (80% Caucasians. An observational study analyzed dairy calcium intakes of 1526 female and 372 male Dutch fracture patients older than 50. On average, participants reported three dairy servings per day, independently of age, gender or population density. Median calcium intake from dairy was 790 mg/day in females and males. Based on dairy products alone, 11.3% of women and 14.2% of men complied with Dutch recommendations for calcium intake (adults ≤ 70 years: 1100 mg/day and >70 years: 1200 mg/day. After including 450 mg calcium from basic nutrition, compliance raised to 60.5% and 59.1%, respectively, compared to 53.2% in the U.S. cohort. Daily dairy calcium intake is not associated with femoral neck bone mineral density (BMD T-scores or WHO Fracture Assessment Tool (FRAX risk scores for major fracture or hip fracture. However, when sub analyzing the male cohort, these associations were weakly negative. The prevalence of maternal hip fracture was a factor for current fracture risks, both in women and men. While daily dairy calcium intake of Dutch fracture patients was well below the recommended dietary intake, it was comparable to intakes in a healthy U.S. cohort. This questions recommendations for adding more additional dairy products to preserve adult skeletal health, particularly when sufficient additional calcium is derived from adequate non-dairy nutrition.

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


    Bizzozero, Julien; Scrivener, Karen


    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 ...

  19. Mixed calcium-magnesium pre-nucleation clusters enrich calcium


    Verch, Andreas; Antonietti, Markus; Cölfen, Helmut


    It is demonstrated that magnesium and carbonate ions can form pre-nucleation clusters in analogy to calcium carbonate. If a mixed calcium and magnesium solution is brought in contact with carbonate ions, mixed pre-nucleation clusters form. The equilibrium constants for their formation are reported revealing that over the entire range of possible cation mixing ratios, calcium gets enriched over magnesium in the pre-nucleation clusters. This can explain high magnesium contents in amorphous calc...

  20. Biological Reactions to Calcium Phosphate-coated Calcium Carbonate Particles

    National Research Council Canada - National Science Library

    Tetsunari NISHIKAWA; Kazuya MASUNO; Tomoharu OKAMURA; Kazuya TOMINAGA; Masahiro WATO; Mayu KOKUBU; Koichi IMAI; Shoji TAKEDA; Yoichro TAGUCHI; Masatoshi UEDA; Akio TANAKA


    [SYNOPSIS][Objectives]: In order to histopathologically investigate biological reactions to materials used for scaffolds, we examined the cytotoxicity to calcium particles in vitro and bioabsorption in vivo...

  1. The effect of calcium on the properties of charged phospholipid bilayers

    DEFF Research Database (Denmark)

    Pedersen, U.R.; Leidy, Chad; Westh, P.


    to sodium ions, calcium ions are localised in a narrow (∼ 10 Å) band around the phosphate group. The interaction of calcium with the lipid molecules enhances the molecular packing of the PG and PS lipids. This observation is in good agreement with emission spectra of the membrane partitioning probe Laurdan......-myristoyl-phosphatidyl-serine (DMPS) bilayers as well as a protonated di-myristoyl-phosphatidyl-serine (DMPSH) bilayer. We were particularly interested in calcium ions due to their important role in biological systems. Simulations performed in the presence of calcium ions (DMPG, DMPS) or sodium ions (DMPS) were run for 45–60 ns...... affected by the counterions, where calcium ions have a more pronounced effect than sodium ions. Calcium ions were found to be tightly bound to the anionic groups of the lipid molecules and as such appear to constitute an integral part of the membrane interface on nanoseconds time scales. In contrast...

  2. Osteoporosis, calcium and physical activity.


    Martin, A. D.; Houston, C S


    Sales of calcium supplements have increased dramatically since 1983, as middle-aged women seek to prevent or treat bone loss due to osteoporosis. However, epidemiologic studies have failed to support the hypothesis that larger amounts of calcium are associated with increased bone density or a decreased incidence of fractures. The authors examine the evidence from controlled trials on the effects of calcium supplementation and physical activity on bone loss and find that weight-bearing activit...

  3. Cardiovascular Effects of Calcium Supplements

    Directory of Open Access Journals (Sweden)

    Ian R. Reid


    Full Text Available Calcium supplements reduce bone turnover and slow the rate of bone loss. However, few studies have demonstrated reduced fracture incidence with calcium supplements, and meta-analyses show only a 10% decrease in fractures, which is of borderline statistical and clinical significance. Trials in normal older women and in patients with renal impairment suggest that calcium supplements increase the risk of cardiovascular disease. To further assess their safety, we recently conducted a meta-analysis of trials of calcium supplements, and found a 27%–31% increase in risk of myocardial infarction, and a 12%–20% increase in risk of stroke. These findings are robust because they are based on pre-specified analyses of randomized, placebo-controlled trials and are consistent across the trials. Co-administration of vitamin D with calcium does not lessen these adverse effects. The increased cardiovascular risk with calcium supplements is consistent with epidemiological data relating higher circulating calcium concentrations to cardiovascular disease in normal populations. There are several possible pathophysiological mechanisms for these effects, including effects on vascular calcification, vascular cells, blood coagulation and calcium-sensing receptors. Thus, the non-skeletal risks of calcium supplements appear to outweigh any skeletal benefits, and are they appear to be unnecessary for the efficacy of other osteoporosis treatments.

  4. Laser Sintered Calcium Phosphate Bone

    National Research Council Canada - National Science Library

    Vail, Neil


    ...) technology selective laser sintering (SLS). BME has successfully implemented a pilot facility to fabricate calcium phosphate implants using anatomical data coupled with the selective laser sintering process...

  5. 21 CFR 73.1070 - Calcium carbonate. (United States)


    ... precipitated calcium carbonate (CaCO3). (2) Color additive mixtures for drug use made with calcium carbonate... precipitated calcium carbonate in the United States Pharmacopeia XX (1980). (c) Uses and restrictions. Calcium... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Calcium carbonate. 73.1070 Section 73.1070 Food...

  6. 21 CFR 184.1191 - Calcium carbonate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium carbonate. 184.1191 Section 184.1191 Food... Specific Substances Affirmed as GRAS § 184.1191 Calcium carbonate. (a) Calcium carbonate (CaCO3, CAS Reg... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation...

  7. Be Brave PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    In this 60-second public service announcement, gynecologic cancer survivor, Jenny Allen, urges women to see a doctor if symptoms last two weeks or more.  Created: 8/4/2011 by National Center for Chronic Disease Prevention and Health Promotion.   Date Released: 8/4/2011.

  8. Opioid Prescribing PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the July 2017 CDC Vital Signs report. Higher opioid prescribing puts patients at risk for addiction and overdose. Learn what can be done about this serious problem.  Created: 7/6/2017 by Centers for Disease Control and Prevention (CDC).   Date Released: 7/6/2017.

  9. Babesiosis PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second PSA describes babesiosis, a preventable and treatable tickborne disease, including the signs and symptoms of infection and ways to prevent it.  Created: 4/25/2012 by Center for Global Health, Division of Parasitic Diseases and Malaria.   Date Released: 4/26/2012.

  10. FFA at 60. (United States)

    Harris, C. Coleman; And Others


    Consists of eight articles commemorating the 60th birthday of Future Farmers of America. Topics include (1) planning for the future, (2) private sector support, (3) international opportunities, (4) alumni support, (5) leadership and personal development, (6) public image, (7) agriscience, and (8) the agrimarketing initiative. (CH)

  11. Calcium signalling: fishing out molecules of mitochondrial calcium transport. (United States)

    Hajnóczky, György; Csordás, György


    Cellular energy metabolism, survival and death are controlled by mitochondrial calcium signals originating in the cytoplasm. Now, RNAi studies link three proteins - MICU1, NCLX and LETM1 - to the previously unknown molecular mechanism of mitochondrial calcium transport. Copyright © 2010 Elsevier Ltd. All rights reserved.

  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


    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 off...

  13. Calcium, vitamin D, and your bones (United States)

    ... page: // 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 ...

  14. Calcium Supplements: Do Men Need Them Too? (United States)

    ... Lifestyle Nutrition and healthy eating Should men take calcium supplements? Answers from Katherine Zeratsky, R.D., L. ... Most healthy men don't need to take calcium supplements. Calcium is important for men for optimal ...

  15. 60th Anniversary

    CERN Multimedia

    Staff Association


      The Staff Association is happy to announce the start of the festivities for its 60th anniversary. To mark this event, we asked a graphic designer, Kevin Moles, who works with the support of Fabienne Marcastel/DG, to create an anniversary logo. This is the model which was chosen. From now on, you can find the new logo on all our sites, and materials related to the anniversary. We would like to thank Kevin for his work and help. More details of the celebration will be communicated later, but please already reserve the evening of May 21, and come celebrate with us and help us blow out the 60 candles of the Staff Association.

  16. Childhood Obesity PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the August 2013 CDC Vital Signs report. The rate of obesity among low-income preschoolers has declined, but one in eight is still obese. This program briefly discusses what can be done.  Created: 8/6/2013 by Centers for Disease Control and Prevention (CDC).   Date Released: 8/6/2013.

  17. HIV Testing PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the December 2017 CDC Vital Signs report. In the U.S., about 15 percent of people who have HIV don't know they have it. Learn about the importance of testing, early diagnosis, and treatment.  Created: 11/28/2017 by Centers for Disease Control and Prevention (CDC).   Date Released: 11/28/2017.

  18. Heroin Epidemic PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the July 2015 CDC Vital Signs report. Heroin use and heroin-related overdose deaths are increasing. Most people are using it with other drugs, especially prescription opioid painkillers. Learn what can be done to prevent and treat the problem.  Created: 7/7/2015 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 7/7/2015.

  19. Secondhand Smoke PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the February 2015 CDC Vital Signs report. Secondhand smoke kills more than 400 infants and 41,000 adult nonsmokers every year. Learn what can be done to prevent secondhand smoke exposure.  Created: 2/3/2015 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 2/3/2015.

  20. Stable prenucleation calcium carbonate clusters. (United States)

    Gebauer, Denis; Völkel, Antje; Cölfen, Helmut


    Calcium carbonate forms scales, geological deposits, biominerals, and ocean sediments. Huge amounts of carbon dioxide are retained as carbonate ions, and calcium ions represent a major contribution to water hardness. Despite its relevance, little is known about the precipitation mechanism of calcium carbonate, and specified complex crystal structures challenge the classical view on nucleation considering the formation of metastable ion clusters. We demonstrate that dissolved calcium carbonate in fact contains stable prenucleation ion clusters forming even in undersaturated solution. The cluster formation can be characterized by means of equilibrium thermodynamics, applying a multiple-binding model, which allows for structural preformation. Stable clusters are the relevant species in calcium carbonate nucleation. Such mechanisms may also be important for the crystallization of other minerals.

  1. MH-60S Fleet Combat Support Helicopter (MH-60S) (United States)


    Aircraft Corporation was awarded July 6, 2012. These two contracts will complete the MH-60S production buys which conclude in FY 2015. MH-60S...UNCLASSIFIED 10 VMAX (KIAS) *Armed Helo FMC Rate (%) 60 60 56 60 60 *Armed Helo MC Rate (%) 75 75 69 74 74 *HC Interoperability (%) 100 N/A N/A N...Countermeasures Ao - Operational Availability CSAR - Combat Search and Rescue CV - Carrier deg - Degree F - Fahrenheit FMC - Fully Mission Capable G

  2. Hispanic Health PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the May 2015 CDC Vital Signs report. About one in six people living in the U.S. are Hispanic. The two leading causes of death in this group are heart disease and cancer, accounting for two out of five deaths. Unfortunately, many Hispanics face considerable barriers to getting high quality health care, including language and low income. Learn what can be done to reduce the barriers.  Created: 5/5/2015 by Office of Minority Health & Health Equity (OMHHE).   Date Released: 5/5/2015.

  3. Heart Age PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the September 2015 CDC Vital Signs report. Your heart age is the age of your heart and blood vessels as a result of your risk factors for heart attack and stroke. If you smoke or have high blood pressure, your heart age will be much higher than your actual age. Learn what you can do to lower your heart age and keep it low.  Created: 9/1/2015 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 9/1/2015.

  4. GOMA 6.0 :

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, Peter Randall; Rao, Rekha Ranjana; Chen, Ken S; Labreche, Duane A.; Sun, Amy Cha-Tien; Hopkins, Matthew M; Moffat, Harry K.; Roach, Robert Allen; Hopkins, Polly L.; Notz, Patrick K.; Roberts, Scott Alan; Sackinger, Philip A.; Subia, Samuel Ramirez; Wilkes, Edward Dean; Baer, Thomas A.; Noble, David R.; Secor, Robert B.


    Goma 6.0 is a finite element program which excels in analyses of multiphysical processes, particularly those involving the major branches of mechanics (viz. fluid/solid mechanics, energy transport and chemical species transport). Goma is based on a full-Newton-coupled algorithm which allows for simultaneous solution of the governing principles, making the code ideally suited for problems involving closely coupled bulk mechanics and interfacial phenomena. Example applications include, but are not limited to, coating and polymer processing flows, super-alloy processing, welding/soldering, electrochemical processes, and solid-network or solution film drying. This document serves as a users guide and reference.

  5. Trucker Safety PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the March 2015 CDC Vital Signs report. In 2012 in the United States, about 317,000 motor vehicle crashes involved a large truck. Twenty-six thousand truck drivers and their passengers were injured in these crashes, and about 700 died. Learn what can be done to help truck drivers stay safe.  Created: 3/3/2015 by National Institute for Occupational Safety and Health (NIOSH).   Date Released: 3/3/2015.

  6. Preventing Melanoma PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the June 2015 CDC Vital Signs report. Skin cancer is the most common form of cancer in the U.S. In 2011, there were more than 65,000 cases of melanoma, the most deadly form of skin cancer. Learn how everyone can help prevent skin cancer.  Created: 6/2/2015 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 6/2/2015.

  7. The effects of thermal stimuli on intracellular calcium change and histamine releases in rat basophilic leukemia mast cells (United States)

    Wu, Zu-Hui; Zhu, Dan; Chen, Ji-Yao; Zhou, Lu-Wei


    The effects of thermal stimuli on rat basophilic leukemia mast cells were studied. The cells in calcium-contained or calcium-free buffers were thermally stimulated in the temperature range of 25-60 °C. The corresponding calcium ion concentration in cells [Ca2+]i as well as the released histamine from cells was measured with fluorescence staining methods. The ruthenium red (RR), a block of membrane calcium channels (transient receptor potential family V (TRPV)), was used in experiments. Under the stimulus of 25-50 °C, no significant difference on [Ca2+]i was found between these three groups of the cells in calcium-contained buffer without or with RR and cells in calcium-free saline, indicating that the increased calcium in cytosol did not result from the extracellular buffer but came from the intracellular calcium stores. The [Ca2+]i continuously increased under the temperature of 50-60 °C, but the RR and calcium-free saline can obviously diminish the [Ca2+]i increase at these high temperatures, reflecting that the opening of the TRPV2 channels leads to a calcium influx resulting in the [Ca2+]i increment. The histamine release also became significant in these cases. Since the released histamine is a well-known mediator for the microcirculation promotion, the histamine release from mast cells could be one of the mechanisms of thermal therapy.

  8. Bone Mineral Density Accrual in Students with Autism Spectrum Disorders: Effects of Calcium Intake and Physical Training (United States)

    Goodarzi, Mahmood; Hemayattalab, Rasool


    The purpose of this study was to investigate the effects of weight bearing exercise and calcium intake on bone mineral density (BMD) of students with autism spectrum disorders. For this reason 60 boy students with autism disorder (age 8-10 years old) were assigned to four groups with no differences in age, BMD, calcium intake, and physical…

  9. Calcium metabolism & hypercalcemia in adults. (United States)

    Lumachi, F; Motta, R; Cecchin, D; Ave, S; Camozzi, V; Basso, S M M; Luisetto, G


    Calcium is essential for many metabolic process, including nerve function, muscle contraction, and blood clotting. The metabolic pathways that contribute to maintain serum calcium levels are bone remodeling processes, intestinal absorption and secretion, and renal handling, but hypercalcemia occurs when at least 2 of these 3 metabolic pathways are altered. Calcium metabolism mainly depends on the activity of parathyroid hormone (PTH). Its secretion is strictly controlled by the ionized serum calcium levels through a negative feed-back, which is achieved by the activation of calcium-sensing receptors (CaSRs) mainly expressed on the surface of the parathyroid cells. The PTH receptor in bone and kidney is now referred as PTHR1. The balance of PTH, calcitonin, and vitamin D has long been considered the main regulator of calcium metabolism, but the function of other actors, such as fibroblast growth factor-23 (FGF-23), Klotho, and TPRV5 should be considered. Primary hyperparathyroidism and malignancy are the most common causes of hypercalcemia, accounting for more than 90% of cases. Uncontrolled hypercalcemia may cause renal impairment, both temporary (alteration of renal tubular function) and progressive (relapsing nephrolithiasis), leading to a progressive loss of renal function, as well as severe bone diseases, and heart damages. Advances in the understanding of all actors of calcium homeostasis will be crucial, having several practical consequences in the treatment and prevention of hypercalcemia. This would allow to move from a support therapy, sometimes ineffective, to a specific and addressed therapy, especially in patients with chronic hypercalcemic conditions unsuitable for surgery.

  10. Calcium and Calcium Supplements: Achieving the Right Balance (United States)

    ... Duyff RL. American Dietetic Association Complete Food and Nutrition Guide. 4th ed. Hoboken, N.J.: John Wiley & Sons; 2012:140. Rosen HN. Calcium and vitamin D supplementation in osteoporosis. ...

  11. Calcium carbonate and calcium sulfate in Martian meteorite EETA79001 (United States)

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


    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.

  12. 21 CFR 184.1187 - Calcium alginate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005.... Calcium alginate is prepared by the neutralization of purified alginic acid with appropriate pH control...

  13. Extracellular and Intracellular Regulation of Calcium Homeostasis

    Directory of Open Access Journals (Sweden)

    Felix Bronner


    Full Text Available An organism with an internal skeleton must accumulate calcium while maintaining body fluids at a well-regulated, constant calcium concentration. Neither calcium absorption nor excretion plays a significant regulatory role. Instead, isoionic calcium uptake and release by bone surfaces causes plasma calcium to be well regulated. Very rapid shape changes of osteoblasts and osteoclasts, in response to hormonal signals, modulate the available bone surfaces so that plasma calcium can increase when more low-affinity bone calcium binding sites are made available and can decrease when more high-affinity binding sites are exposed. The intracellular free calcium concentration of body cells is also regulated, but because cells are bathed by fluids with vastly higher calcium concentration, their major regulatory mechanism is severe entry restriction. All cells have a calcium-sensing receptor that modulates cell function via its response to extracellular calcium. In duodenal cells, the apical calcium entry structure functions as both transporter and a vitamin D–responsive channel. The channel upregulates calcium entry, with intracellular transport mediated by the mobile, vitamin D–dependent buffer, calbindin D9K, which binds and transports more than 90% of the transcellular calcium flux. Fixed intracellular calcium binding sites can, like the body's skeleton, take up and release calcium that has entered the cell, but the principal regulatory tool of the cell is restricted entry.

  14. Calcium phosphates for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Canillas, M.; Pena, P.; Aza, A.H. de; Rodriguez, M.A.


    The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies. (Author)

  15. Polysulfide calcium as multyfunctional product

    Directory of Open Access Journals (Sweden)

    G. Abramova


    Full Text Available A modified method of producing of polysulfide calcium, the influence of various factors on the degree of polysulfide of product, as well as possible directions for its use as a multifunctional compound were considered.

  16. [Calcium metabolism after the menopause]. (United States)

    Kanovitch, D; Klotz, H P


    The authors recall the antagonism between estradiol and parathormone. Estradiol tends to lower serum calcium and fix calcium in the bones as shown by one of us 25 years ago. The mechanism of this action of estrogen on calcium metabolism has been determined by numerous authors but some points are still not clear, e.g. the interferences between estrogen and calcitonin. Classically, parathormone is known to increase bony reabsorption and raise serum calcium. After the menopause the gradual reduction in estradiol secretion leads to post-menopausal osteoporosis. It is better to administer estrogens prophylactically to women after the menopause provided a cervical smear and mammography have been carried out to eliminate latent carcinoma of the breast or uterine cervix.

  17. Calcium-sensing beyond neurotransmitters

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Han, Weiping


    Neurotransmitters, neuropeptides and hormones are released through the regulated exocytosis of SVs (synaptic vesicles) and LDCVs (large dense-core vesicles), a process that is controlled by calcium. Synaptotagmins are a family of type 1 membrane proteins that share a common domain structure. Most....... Also, we discuss potential roles of synaptotagmins in non-traditional endocrine systems....... synaptotagmins are located in brain and endocrine cells, and some of these synaptotagmins bind to phospholipids and calcium at levels that trigger regulated exocytosis of SVs and LDCVs. This led to the proposed synaptotagmin-calcium-sensor paradigm, that is, members of the synaptotagmin family function...... as calcium sensors for the regulated exocytosis of neurotransmitters, neuropeptides and hormones. Here, we provide an overview of the synaptotagmin family, and review the recent mouse genetic studies aimed at understanding the functions of synaptotagmins in neurotransmission and endocrine-hormone secretion...

  18. The influence of calcium supplementation on immobilised mixed microflora for biohydrogen production (United States)

    Lutpi, Nabilah Aminah; Shian, Wong Yee; Izhar, Tengku Nuraiti Tengku; Zainol, Noor Ainee; Kiong, Yiek Wee


    This study is aim to study the effect of calcium as supplement in attached growth system towards the enhancement of the hydrogen production performance. The effects of calcium ion for thermophilic biohydrogen production were studied by using a mixed culture, from palm oil mill effluent sludge and granular activated carbon (GAC) as the support material. Batch experiments were carried out at 60°C by feeding the anaerobic sludge bacteria with sucrose-containing synthetic medium at an initial pH of 5.5 under anaerobic conditions. The repeated batch cultivation process was conducted by adding different concentration of calcium at range 0.025g/L to 0.15g/L. The results showed that the calcium at 0.1 g/L was the optimal concentration to enhance the fermentative hydrogen production under thermophilic (60°C) conditions.

  19. Antimicrobial effect of calcium hydroxide as endo intracanal dressing on Streptococcus viridans

    Directory of Open Access Journals (Sweden)

    Nanik Zubaidah


    Full Text Available Calcium hydroxide had been used as the intra-canal dressing in endodontic treatment due to its high alkaline and antimicrobial capacity. It can also dissolve the necrotic tissue, prevent dental root resorbtion and regenerate a new hard tissue. The aim of this study was to determine the concentration of calcium hydroxide which had the highest antimicrobial effect on Streptococcus viridans. Samples were divided into 5 groups; each group consisted of 8 samples with different concentration of calcium hydroxide. Group I: 50%, group II: 55, Group III: 60%, Group IV: 65%, Group V: 70%. The antimicrobial testing was performed using diffusion method against Streptococcus viridans. The result of susceptibility test was showed by the inhibition zone diameter which measured with caliper (in millimeter. We analyzed the data using One-Way ANOVA test with significant difference 0.05 and subsequently LSD test. The study showed that calcium hydroxide with concentration 60% has the highest antimicrobial effect.

  20. Photophysics of C60 Colloids (United States)


    of C60 Colloids 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Andrew Clements 5d. PROJECT NUMBER 5e. C60 Colloids • Desired NLO Response • Overview of Nonlinear Scattering and Absorption • Previous Scholarship/Context • Thesis Question...Computer Modeling • Conclusions 2 UNCLASSIFIED UNCLASSIFIED Description of C60 Colloids C60 Molecules • Cage molecules composed of 60

  1. A comparison of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning. (United States)

    Bradberry, Sally; Vale, Allister


    This article reviews the experimental and clinical studies that have compared the efficacy (impact on urine lead excretion, blood and tissue lead concentrations, resolution of features and survival) of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning. It also summarizes the pharmacokinetic and pharmacodynamic aspects and the adverse effects of treatment. Medline, Toxline, and Embase were searched for all available years to June 2009. PHARMACOKINETICS AND PHARMACODYNAMICS: The absorption of oral DMSA is more complete than sodium calcium edetate; the latter has to be administered parenterally. Both antidotes are distributed predominantly extracellularly. Sodium calcium edetate is not metabolized, whereas DMSA is extensively metabolized to mixed disulfides of cysteine. The two antidotes have elimination half-lives of less than 60 min. There is no evidence that either antidote crosses the blood-brain barrier to any major extent. Sodium calcium edetate chelates lead by displacement of the central Ca2+ ion with Pb2+. The nature of the DMSA-lead chelate is less clearly defined. There is evidence that the mixed disulfides of cysteine are the active chelating moiety in humans. If this is the case, this suggests that chelation occurs principally, if not exclusively, in the kidney. The primary source of lead mobilized by sodium calcium edetate is bone with an additional contribution from kidney and liver. Comparison of the experimental studies is complicated by substantial variations in study design, particularly the antidote dose, the route and duration of treatment, the amount and duration of lead dosing, and lack of direct comparison between antidotes (comparison was usually made with control). In experimental studies that used equimolar and clinically relevant antidote doses and assessed the impact of DMSA and sodium calcium edetate on urine lead excretion and/or blood lead concentrations, similar results

  2. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pantothenate, calcium chloride double salt. 172.330 Section 172.330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

  3. Calcium affects on vascular endpoints

    Directory of Open Access Journals (Sweden)

    Patel Vaishali B


    Full Text Available Abstract Calcium is one of the most abundant minerals in the body and its metabolism is one of the basic biologic processes in humans. Although historically linked primarily to bone structural development and maintenance, calcium is now recognized as a key component of many physiologic pathways necessary for optimum health including cardiovascular, neurological, endocrine, renal, and gastrointestinal systems. A recent meta-analysis published in August 2011 showed a potential increase in cardiovascular events related to calcium supplementation. The possible mechanism of action of this correlation has not been well elucidated. This topic has generated intense interest due to the widespread use of calcium supplements, particularly among the middle aged and elderly who are at the most risk from cardiac events. Prior studies did not control for potential confounding factors such as the use of statins, aspirin or other medications. These controversial results warrant additional well-designed studies to investigate the relationship between calcium supplementation and cardiovascular outcomes. The purpose of this review is to highlight the current literature in regards to calcium supplementation and cardiovascular health; and to identify areas of future research.

  4. Acknowledgment - Issue 60

    Directory of Open Access Journals (Sweden)

    Executive Editor


    Full Text Available Biblios wish to acknowledge the support of the following professionals who participated in the review process of submissions for our issue 60.ReviewersAndré Ancona Lopez (Universidade de Brasília - UnB, BrasilGildenir Carolino Santos (Universidade Estadual de Campinas - UNICAMP, BrasilJacira Gil Bernardes (Universidade Federal do Rio Grande do Sul - UFRGS, BrasilRodrigo Donoso Vegas (Universidad de Chile - UCHILE, ChileSaúl Hiram Souto Fuentes (Universidad de Monterrey - UDEM, MéxicoReviewers invitedAlejandro Uribe Tirado (Universidad de Antioquia - UDEA, ColombiaFernanda Passini Moreno (Universidade de Brasília - UnB, BrasilJosé Bernal Rivas Fernández (Universidad de Costa Rica - UCR, Costa RicaMarta Lígia Pomim Valentim (Universidade Estadual Paulista - UNESP, BrasilOrlando Corzo Cauracurí (Universidad Nacional Mayor de San Marcos - UNMSM, PerúTerezinha Elisabeth da Silva (Universidade Estadual de Londrina - UEL, BrasilZaira Regina Zafalon (Universidade Federal de São Carlos - UFSCAR, BrasilIn the same way our acknowledge to University Library System (University of Pittsburgh - PITTS, USA by constant technical support and advice for our journal.

  5. 60 years of celebrations

    CERN Multimedia

    Katarina Anthony


    The first celebration of CERN's anniversary featured in the CERN Bulletin, 1979. As CERN wraps up a month of events surrounding its 60th anniversary, the Bulletin looks back on September 29ths that have come and gone. What was hitting the CERN headlines when the Organization turned 15 - 30 - 45? Brace yourselves for a trip back in time with previous birthday editions of the CERN (a.k.a. "Weekly") Bulletin.      Bulletin Issue No.1/1965  - Bulletin Issue No. 40/1969 The very first edition of the Weekly Bulletin arrived on CERN desktops on 29 March 1965. The Organization was only just out of its first decade, but it was already a hub of activity, as demonstrated by the various seminars and training events that graced the cover of the first Bulletin. By the time CERN turned 15 in 1969, the Organization was preparing for its second Open Day. Discussion of the event made the cover of the Bulletin, announcing that sections of the ISR were to be ...

  6. New Volleyballenes: Y20C60, La20C60, and Lu20C60


    Wang, Jing; Liu, Ying


    New stable Volleyballenes Y20C60, La20C60, and Lu20C60 molecular clusters have been proposed using first-principles density functional theory studies. In conjunction with recent findings for the scandium system, these findings establish Volleyballene M20C60 molecules as a stable general class of fullerene family. All M20C60 (M=Y, La, and Lu) molecules have Th point group symmetries and relatively large HOMO-LUMO gaps.

  7. Particle size of calcium carbonate does not affect apparent and standardized total tract digestibility of calcium, retention of calcium, or growth performance of growing pigs. (United States)

    Merriman, L A; Stein, H H


    Two experiments were conducted to evaluate particle size of calcium carbonate used in diets fed to growing pigs. Experiment 1 was conducted to determine apparent total tract digestibility (ATTD), standardized total tract digestibility (STTD), and retention of Ca among diets containing calcium carbonate produced to different particle sizes, and Exp. 2 was conducted to determine if growth performance of weanling pigs is affected by particle size of calcium carbonate. In Exp. 1, 4 diets based on corn and potato protein isolate were formulated to contain 0.70% Ca and 0.33% standardized total tract digestible P, but the calcium carbonate used in the diets was ground to 4 different particle sizes (200, 500, 700, or 1,125 μm). A Ca-free diet was formulated to determine basal endogenous losses of Ca. In Exp. 2, 4 diets were based on corn and soybean meal and the only difference among diets was that each diet contained calcium carbonate ground to the 4 particle sizes used in Exp. 1. In Exp. 1, 40 barrows (15.42 ± 0.70 kg initial BW) were allotted to the 5 diets with 8 replicate pigs per diet using a randomized complete block design, and in Exp. 2, 128 pigs with an initial BW of 9.61 ± 0.09 kg were randomly allotted to 4 experimental diets. Results of Exp. 1 indicated that basal endogenous losses of Ca were 0.329 g/kg DMI. The ATTD of Ca was 70.0 ± 3.2, 74.3 ± 2.7, 70.0 ± 2.9, and 72.1 ± 2.7 and the STTD of Ca was 74.2 ± 3.2, 78.5 ± 2.7, 74.1 ± 2.9, and 76.2 ± 2.7 for calcium carbonate ground to 200, 500, 700, or 1,125 μm, respectively. Retention of Ca was 67.4 ± 3.1, 70.4 ± 2.6, 63.9 ± 2.8, and 67.2 ± 2.2 for diets containing calcium carbonate ground to 200, 500, 700, or 1,125 μm, respectively. There were no differences among diets for ATTD of Ca, STTD of Ca, or retention of Ca. The ATTD of P was 64.5 ± 1.7, 66.8 ± 2.6, 64.2 ± 3.0, and 63.2 ± 1.7% and retention of P was 61.4 ± 1.4, 63.8 ± 2.8, 61.9 ± 2.8, and 60.9 ± 1.5 for diets containing calcium

  8. Calcium: the molecular basis of calcium action in biology and medicine

    National Research Council Canada - National Science Library

    Pochet, Roland; Donato, Rosario


    ... of Calcium Calcium Signalling in Excitable Cells Ca2+ Release in Muscle Cells by N. Macrez and J. Mironneau Calcium Signalling in Neurons Exemplified by Rat Sympathetic Ganglion Cells by S.J. M...

  9. Calcium supplementation increases blood creatinine concentration in a randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Elizabeth L Barry

    Full Text Available Calcium supplements are widely used among older adults for osteoporosis prevention and treatment. However, their effect on creatinine levels and kidney function has not been well studied.We investigated the effect of calcium supplementation on blood creatinine concentration in a randomized controlled trial of colorectal adenoma chemoprevention conducted between 2004-2013 at 11 clinical centers in the United States. Healthy participants (N = 1,675 aged 45-75 with a history of colorectal adenoma were assigned to daily supplementation with calcium (1200 mg, as carbonate, vitamin D3 (1000 IU, both, or placebo for three or five years. Changes in blood creatinine and total calcium concentration were measured after one year of treatment and multiple linear regression was used to estimate effects on creatinine concentrations.After one year of treatment, blood creatinine was 0.013±0.006 mg/dL higher on average among participants randomized to calcium compared to placebo after adjustment for other determinants of creatinine (P = 0.03. However, the effect of calcium treatment appeared to be larger among participants who consumed the most alcohol (2-6 drinks/day or whose estimated glomerular filtration rate (eGFR was less than 60 ml/min/1.73 m2 at baseline. The effect of calcium treatment on creatinine was only partially mediated by a concomitant increase in blood total calcium concentration and was independent of randomized vitamin D treatment. There did not appear to be further increases in creatinine after the first year of calcium treatment.Among healthy adults participating in a randomized clinical trial, daily supplementation with 1200 mg of elemental calcium caused a small increase in blood creatinine. If confirmed, this finding may have implications for clinical and public health recommendations for calcium NCT00153816.

  10. Prevention of Fractures in Older People with Calcium and Vitamin D

    Directory of Open Access Journals (Sweden)

    Caryl A. Nowson


    Full Text Available The greatest cause of fracture in older people is osteoporosis which contributes to increased morbidity and mortality in older people. A number of meta-analyses have been performed assessing the effectiveness of calcium supplementation alone, vitamin D supplementation alone and the combined therapy on bone loss and fracture reduction in older people. The results of these meta-analyses indicate that vitamin D supplementation alone is unlikely to reduce fracture risk, calcium supplementation alone has a modest effect in reducing total fracture risk, but compliance with calcium supplements is poor in the long term. The combination of calcium supplementation with vitamin D supplementation, particularly in those at risk of marginal and low vitamin D status reduces total fractures, including hip fractures. Therefore older people would be recommended to consume adequate dietary calcium (>1100 mg/day together with maintaining adequate vitamin D status (>60 nmol/L 25(OHD to reduce risk of fracture. It is a challenge to consume sufficient dietary calcium from dietary sources, but the increasing range of calcium fortified foods could assist in increasing the dietary calcium intake of older people. In addition to the usual dairy based food sources, vitamin D supplements are likely to be required for older people with reduced mobility and access to sunlight.

  11. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

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


    Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX....... Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none TTX-sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon...... 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...

  12. [Evaluation of the calcium intake in population of Marrakesh and its region: 1000 cases]. (United States)

    Ait Ouazar, M; Amine, M; Harifi, G; Ouilki, I; Younsi, R; Belkhou, A; El Bouchti, I; El Hassani, S


    The aim of our work is to evaluate the calcium intake in population of Marrakesh and its region by the translated version in Moroccan Arabic dialect of Fardellone questionnaire. The version translated into Arabic dialect Fardellone questionnaire is tested on a sample of 1000 subjects. The subjects aged less than 15 years accounted for 30.9% (n=309), those aged 15 to 59 62% (n=620) and those aged over 60 years 7.1% (n=71). The distribution by age group is calculated on the distribution of the Moroccan population. The study population includes 60.6% women (n=606), 39.4% of men (n=394). The mean calcium intake was respectively 5875 mg by week (that means 839 mg/day), 4899 mg by week (that means 699 mg/day), 3053 mg by week (that means 436 mg/day), in subjects aged less than 15, those aged 15 to 59, and those aged over 60 years. The average consumption of calcium per day is significantly lower than the recommended daily amount for the three age groups. Patients aged over 60 years is the age group most under nourished calcium. The comparison of both gender found a deficit higher among women than among men. Evaluation of the calcium intake is an essential tool for better management of metabolic bone diseases. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.

  13. Calcium metabolism and cardiovascular function after spaceflight (United States)

    Hatton, Daniel C.; Yue, Qi; Dierickx, Jacqueline; Roullet, Chantal; Otsuka, Keiichi; Watanabe, Mitsuaki; Coste, Sarah; Roullet, Jean Baptiste; Phanouvang, Thongchan; Orwoll, Eric; hide


    To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P parathyroid hormone levels (P animals (P = 0.057). However, mean arterial pressure was elevated (P animals fed low- compared with high-calcium diets (P parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.

  14. [Regulatory mechanism of calcium metabolism. (United States)

    Ozono, Keiichi

    It is often difficult for terrestrial animals to take enough calcium. To maintain serum or extracellular calcium levels is very important for muscle and nerve function. Two major regulators to increase the serum calcium levels are parathyroid hormone(PTH)and vitamin D. PTH binds to the G protein coupling receptor, PTH1R, and increases intracellular cAMP levels. Impirement in the PTH signalling causes many diseases such as pseudohypoparathyroidism and acrodysostosis with hormone resistance. Vitamin D is activated to 1,25-dihydroxyvitamin D[1,25(OH)2D]by two steps of hydroxylation which occurs in the Liver and Kidney. Then, 1,25(OH)2D binds to vitamin D receptor(VDR), which works as a ligand-dependent transcription factor. Hypocalcemia and hypercalcemia are caused by various disorders including abnormal regulation of PTH and vitamin D production and their signal transduction.

  15. Calcium signaling and cell proliferation. (United States)

    Pinto, Mauro Cunha Xavier; Kihara, Alexandre Hiroaki; Goulart, Vânia A M; Tonelli, Fernanda M P; Gomes, Katia N; Ulrich, Henning; Resende, Rodrigo R


    Cell proliferation is orchestrated through diverse proteins related to calcium (Ca(2+)) signaling inside the cell. Cellular Ca(2+) influx that occurs first by various mechanisms at the plasma membrane, is then followed by absorption of Ca(2+) ions by mitochondria and endoplasmic reticulum, and, finally, there is a connection of calcium stores to the nucleus. Experimental evidence indicates that the fluctuation of Ca(2+) from the endoplasmic reticulum provides a pivotal and physiological role for cell proliferation. Ca(2+) depletion in the endoplasmatic reticulum triggers Ca(2+) influx across the plasma membrane in an phenomenon called store-operated calcium entries (SOCEs). SOCE is activated through a complex interplay between a Ca(2+) sensor, denominated STIM, localized in the endoplasmic reticulum and a Ca(2+) channel at the cell membrane, denominated Orai. The interplay between STIM and Orai proteins with cell membrane receptors and their role in cell proliferation is discussed in this review. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Calcium regulation of muscle contraction. (United States)

    Szent-Györgyi, A G


    Calcium triggers contraction by reaction with regulatory proteins that in the absence of calcium prevent interaction of actin and myosin. Two different regulatory systems are found in different muscles. In actin-linked regulation troponin and tropomyosin regulate actin by blocking sites on actin required for complex formation with myosin; in myosin-linked regulation sites on myosin are blocked in the absence of calcium. The major features of actin control are as follows: there is a requirement for tropomyosin and for a troponin complex having three different subunits with different functions; the actin displays a cooperative behavior; and a movement of tropomyosin occurs controlled by the calcium binding on troponin. Myosin regulation is controlled by a regulatory subunit that can be dissociated in scallop myosin reversibly by removing divalent cations with EDTA. Myosin control can function with pure actin in the absence of tropomyosin. Calcium binding and regulation of molluscan myosins depend on the presence of regulatory light chains. It is proposed that the light chains function by sterically blocking myosin sites in the absence of calcium, and that the "off" state of myosin requires cooperation between the two myosin heads. Both myosin control and actin control are widely distributed in different organisms. Many invertebrates have muscles with both types of regulation. Actin control is absent in the muscles of molluscs and in several minor phyla that lack troponin. Myosin control is not found in striated vertebrate muscles and in the fast muscles of crustacean decapods, although regulatory light chains are present. While in vivo myosin control may not be excluded from vertebrate striated muscles, myosin control may be absent as a result of mutations of the myosin heavy chain.

  17. Calcium and boron for in vitro rooting of Nothofagus nervosa. (United States)

    Martínez Pastur, G M; Arena, M; Curvetto, N


    Several mineral compounds influence adventitious rooting, and those containing boron and calcium, play an important role. They are associated to the enzyme regulation, cell division, cellular metabolism (induction stage) and roots enlargement (expression stage). The aims of this work were to study the variation of the endogenous calcium and boron concentrations along the rooting, and determine their optimal concentrations in the rooting basal medium of Nothofagus nervosa. Significant variation in endogenous calcium concentrations was detected along the rooting phase, strongly correlated with rhizogenesis phenomenons and linked to total peroxidase variation as cited elsewhere. Calcium and boron concentrations in the basal medium significantly affected the rooting. Treatment containing 60 mg.L-1 Ca and 1 mg.L-1 B produced root formation in fewer days than other combinations. The variation of these nutrient concentrations in the medium is a useful tool to improve microcutting rooting. Roots are obtained earlier and in a shorter period of time, finally resulting in more homogeneous microplants with a better developed rooting system.

  18. Calcium ferrite formation from the thermolysis of calcium tris (maleato)

    Indian Academy of Sciences (India)

    stoichiometric quantities of aqueous solutions of calcium maleate, iron(III) maleate and maleic acid. The reaction mixture was concentrated on a water bath until a brown coloured product formed after the addition of excess of acetone. The complex was vacuum dried and its identity was established by chemical analysis.

  19. Calcium ferrite formation from the thermolysis of calcium tris ...

    Indian Academy of Sciences (India)

    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 ...

  20. MH-60R Multi-Mission Helicopter (MH-60R) (United States)


    Operations that replaces the aging SH-60B and SH-60F helicopters. The avionics upgrades over the existing SH-60B/F include: a glass cockpit common...1087 Contract Number: N00019-11-C-0077 Contract Type: Firm Fixed Price (FFP) Award Date: September 27, 2011 Definitization Date: September 27...2011 Contract Price Initial Contract Price ($M) Current Contract Price ($M) Estimated Price At Completion ($M) Target Ceiling Qty Target Ceiling Qty

  1. Calcium supplementation commencing before or early in pregnancy, or food fortification with calcium, for preventing hypertensive disorders of pregnancy. (United States)

    Hofmeyr, G Justus; Manyame, Sarah


    Pre-eclampsia is considerably more prevalent in low- than high-income countries. One possible explanation for this discrepancy is dietary differences, particularly calcium deficiency. Calcium supplementation in the second half of pregnancy reduces the serious consequences of pre-eclampsia and is recommended by the World Health Organization (WHO) for women with low dietary calcium intake, but has limited effect on the overall risk of pre-eclampsia. It is important to establish whether calcium supplementation before and in early pregnancy has added benefit. Such evidence would be justification for population-level fortification of staple foods with calcium. To determine the effect of calcium supplementation or food fortification with calcium, commenced before or early in pregnancy and continued at least until mid-pregnancy, on pre-eclampsia and other hypertensive disorders, maternal morbidity and mortality, as well as fetal and neonatal outcomes. We searched the Cochrane Pregnancy and Childbirth Trials Register (10 August 2017), PubMed (29 June 2017),, the WHO International Clinical Trials Registry Platform (ICTRP) (10 August 2017) and reference lists of retrieved studies. Randomised controlled trials of calcium supplementation or food fortification which include women of child bearing age not yet pregnant, or in early pregnancy. Cluster-RCTs, quasi-RCTs and trials published in abstract form only would have been eligible for inclusion in this review but none were identified. Cross-over designs are not appropriate for this intervention.The scope of this review is to consider interventions including calcium supplementation with or without additional supplements or treatments, compared with placebo or no intervention. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. This review is based on one RCT (involving 60 women) which looked at calcium plus additional supplements

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

    Directory of Open Access Journals (Sweden)

    Dmitry eSamigullin


    Full Text Available 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 dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 рА and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 µM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity.

  3. Calcium fertilization increases the concentration of calcium in sapwood and calcium oxalate in foliage of red spruce (United States)

    Kevin T. Smith; Walter C. Shortle; Jon H. Connolly; Rakesh Minocha; Jody Jellison


    Calcium cycling plays a key role in the health and productivity of red spruce forests in the northeastern US. A portion of the flowpath of calcium within forests includes translocation as Ca2+ in sapwood and accumulation as crystals of calcium oxalate in foliage. Concentrations of Ca in these tree tissues have been used as markers of...

  4. Calcium release from experimental dental materials. (United States)

    Okulus, Zuzanna; Buchwald, Tomasz; Voelkel, Adam


    The calcium release from calcium phosphate-containing experimental dental restorative materials was examined. The possible correlation of ion release with initial calcium content, solubility and degree of curing (degree of conversion) of examined materials was also investigated. Calcium release was measured with the use of an ion-selective electrode in an aqueous solution. Solubility was established by the weighing method. Raman spectroscopy was applied for the determination of the degree of conversion, while initial calcium content was examined with the use of energy-dispersive spectroscopy. For examined materials, the amount of calcium released was found to be positively correlated with solubility and initial calcium content. It was also found that the degree of conversion does not affect the ability of these experimental composites to release calcium ions. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Familial hypocalciuric hypercalcemia and calcium sensing receptor

    DEFF Research Database (Denmark)

    Mrgan, Monija; Nielsen, Sanne; Brixen, Kim


    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...

  6. Vitamin D, Calcium, and Bone Health (United States)

    ... Bone Health Featured Resource Find an Endocrinologist Search Vitamin D, Calcium, and Bone Health March 2012 Download ... also helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin ...

  7. 21 CFR 184.1229 - Calcium stearate. (United States)


    ... Specific Substances Affirmed as GRAS § 184.1229 Calcium stearate. (a) Calcium stearate (Ca(C17H35COO)2, CAS Reg. No. 1529-23-0) is the calcium salt of stearic acid derived from edible sources. It is prepared as... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium stearate. 184.1229 Section 184.1229 Food...

  8. Bioactive and Hemocompatible Calcium Sulphoaluminate Cement


    Acuña-Gutiérrez, Iván Omar; Escobedo-Bocardo, José Concepción; Almanza-Robles, José Manuel; Cortés-Hernández, Dora Alicia; Saldívar-Ramírez, Mirna María Guadalupe; Reséndiz-Hernández, Perla Janet; Zugasti-Cruz, Alejandro


    Calcium sulphoaluminate cement (CSAC) is an attractive candidate for biomedical applications due to its appropriate mechanical properties and high calcium content. In vitro bioactivity and hemocompatibility of calcium sulphoaluminate cement were assessed. The cement was prepared from a mixture of calcium sulphoaluminate (CSA) clinker, gypsum and water. Cement samples were immersed in a simulated body fluid (SBF) at 37 °C for different periods of time (7, 14 and 21 days). The analyses of these...

  9. Calcium Balance in Chronic Kidney Disease


    Hill Gallant, Kathleen M.; Spiegel, David M.


    Purpose of Review The kidneys play a critical role in the balance between the internal milieu and external environment. Kidney failure is known to disrupt a number of homeostatic mechanisms that control serum calcium and normal bone metabolism. However, our understanding of calcium balance throughout the stages of chronic kidney disease is limited and the concept of balance itself, especially with a cation as complex as calcium, is often misunderstood. Both negative and positive calcium balan...

  10. Calcium Balance in Chronic Kidney Disease. (United States)

    Hill Gallant, Kathleen M; Spiegel, David M


    The kidneys play a critical role in the balance between the internal milieu and external environment. Kidney failure is known to disrupt a number of homeostatic mechanisms that control serum calcium and normal bone metabolism. However, our understanding of calcium balance throughout the stages of chronic kidney disease is limited and the concept of balance itself, especially with a cation as complex as calcium, is often misunderstood. Both negative and positive calcium balance have important implications in patients with chronic kidney disease, where negative balance may increase risk of osteoporosis and fracture and positive balance may increase risk of vascular calcification and cardiovascular events. Here, we examine the state of current knowledge about calcium balance in adults throughout the stages of chronic kidney disease and discuss recommendations for clinical strategies to maintain balance as well as future research needs in this area. Recent calcium balance studies in adult patients with chronic kidney disease show that neutral calcium balance is achieved with calcium intake near the recommended daily allowance. Increases in calcium through diet or supplements cause high positive calcium balance, which may put patients at risk for vascular calcification. However, heterogeneity in calcium balance exists among these patients. Given the available calcium balance data in this population, it appears clinically prudent to aim for recommended calcium intakes around 1000 mg/day to achieve neutral calcium balance and avoid adverse effects of either negative or positive calcium balance. Assessment of patients' dietary calcium intake could further equip clinicians to make individualized recommendations for meeting recommended intakes.

  11. Electrochemical Induced Calcium Phosphate Precipitation

    NARCIS (Netherlands)

    Lei, Yang; Song, Bingnan; Weijden, van der Renata D.; Saakes, M.; Buisman, Cees J.N.


    Phosphorus (P) is an essential nutrient for living organisms and cannot be replaced or substituted. In this paper, we present a simple yet efficient membrane free electrochemical system for P removal and recovery as calcium phosphate (CaP). This method relies on in situ formation of hydroxide

  12. 21 CFR 582.7187 - Calcium alginate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is generally...

  13. Abnormalities of serum calcium and magnesium (United States)

    Neonatal hypocalcemia is defined as a total serum calcium concentration of <7 mg/dL or an ionized calcium concentration of <4 mg/dL (1mmol/L). In very low birth weight (VLBW) infants, ionized calcium values of 0.8 to 1 mmol/L are common and not usually associated with clinical symptoms. In larger in...

  14. Modularized study of human calcium signalling pathway

    Indian Academy of Sciences (India)


    When there is an extracellular change, cells get the message either by introduction of calcium ions into ... as it precipitates phosphate, the established energy currency of cells. Prolonged high intracellular calcium ... trigger proteins upon binding with free calcium ion(s) change their confirmation to modulate enzymes and ion ...

  15. 21 CFR 582.1191 - Calcium carbonate. (United States)


    ... Additives § 582.1191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use. This... 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...

  16. 21 CFR 582.5191 - Calcium carbonate. (United States)


    ... Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use. This... 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...

  17. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    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 ...

  18. Mitochondrial Calcium Sparkles Light Up Astrocytes. (United States)

    MacVicar, Brian A; Ko, Rebecca W Y


    Discrete calcium signals in the fine processes of astrocytes are a recent discovery and a new mystery. In a recent issue of Neuron, Agarwal et al. (2017) report that calcium efflux from mitochondria during brief openings of the mitochondrial permeability transition pore (mPTP) contribute to calcium microdomains. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  19. 21 CFR 182.1217 - Calcium phosphate. (United States)


    ... 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). (b...

  20. 21 CFR 582.1217 - Calcium phosphate. (United States)


    ... 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). (b...

  1. ORIGINAL ARTICLES Calcium supplementation to prevent pre ...

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Calcium supplementation to prevent pre-eclampsia - a systematic review. G J Hofmeyr, A Roodt, A N Atallah, L Duley. Background. Calcium supplementation during pregnancy may prevent high blood pressure and preterm labour. Objective. To assess the effects of calcium supplementation.

  2. Calcium Orthophosphate-Based Bioceramics

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin


    Full Text Available Various types of grafts have been traditionally used to restore damaged bones. In the late 1960s, a strong interest was raised in studying ceramics as potential bone grafts due to their biomechanical properties. A bit later, such synthetic biomaterials were called bioceramics. In principle, bioceramics can be prepared from diverse materials but this review is limited to calcium orthophosphate-based formulations only, which possess the specific advantages due to the chemical similarity to mammalian bones and teeth. During the past 40 years, there have been a number of important achievements in this field. Namely, after the initial development of bioceramics that was just tolerated in the physiological environment, an emphasis was shifted towards the formulations able to form direct chemical bonds with the adjacent bones. Afterwards, by the structural and compositional controls, it became possible to choose whether the calcium orthophosphate-based implants remain biologically stable once incorporated into the skeletal structure or whether they were resorbed over time. At the turn of the millennium, a new concept of regenerative bioceramics was developed and such formulations became an integrated part of the tissue engineering approach. Now calcium orthophosphate scaffolds are designed to induce bone formation and vascularization. These scaffolds are often porous and harbor different biomolecules and/or cells. Therefore, current biomedical applications of calcium orthophosphate bioceramics include bone augmentations, artificial bone grafts, maxillofacial reconstruction, spinal fusion, periodontal disease repairs and bone fillers after tumor surgery. Perspective future applications comprise drug delivery and tissue engineering purposes because calcium orthophosphates appear to be promising carriers of growth factors, bioactive peptides and various types of cells.

  3. Oxalate co-precipitation synthesis of calcium zirconate and calcium titanate powders.

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Sanchez, Bernadette A.; Tuttle, Bruce Andrew


    Fine powders of calcium zirconate (CaZrO{sub 3}, CZ) and calcium titanate (CaTiO{sub 3}, CT) were synthesized using a nonaqueous oxalate co-precipitation route from Ca(NO{sub 3}){sub 2}{center_dot}4 H{sub 2}O and group(IV) n-butoxides (Ti(OBu{sup n}){sub 4} or Zr(OBu{sup n}){sub 4}). Several reaction conditions and batch sizes (2-35 g) were explored to determine their influence on final particle size, morphology, and phase. Characterization of the as-prepared oxalate precursors, oven dried oxalate precursors (60-90 C), and calcined powders (635-900 C) were analyzed with TGA/DTA, XRD, TEM, and SEM. Densification and sintering studies on pressed CZ pellets at 1375 and 1400 C were also performed. Through the developed oxalate co-precipitation route, densification temperatures for CZ were lowered by 125 C from the 1500 C firing temperature required for conventional mixed oxide powders. Low field electrical tests of the CZ pellets indicated excellent dielectric properties with dielectric constants of {approx}30 and a dissipation factor of 0.0004 were measured at 1 kHz.

  4. Inhibition of choroidal angiogenesis by calcium dobesilate in normal Wistar and diabetic GK rats. (United States)

    Lameynardie, Stéphane; Chiavaroli, Carlo; Travo, Pierre; Garay, Ricardo P; Parés-Herbuté, Núria


    Calcium dobesilate reduces vascular endothelial growth factor (VEGF) over-expression in diabetic rat retina, but its effect on intraocular angiogenesis is unknown. Therefore, we tested calcium dobesilate for its in vitro and ex vivo effects on choroidal explant angiogenesis in spontaneously diabetic Goto-Kakizaki (GK) rats. Choroidal explants were cultured in gels of collagen. Budded microvessels numbers and VEGF formation were taken as markers of angiogenesis. Ex vivo studies were performed in GK rats orally given 100 mg/kg/day calcium dobesilate for 10 days. In vitro, calcium dobesilate dose- and time-dependently inhibited both microvessel formation and VEGF production, at concentrations >or=25 mug/ml (i.e. >or=60 microM), with complete inhibition at 100 microg/ml. Oral treatment of diabetic GK rats with calcium dobesilate induced a significant reduction of choroidal angiogenesis ex vivo (38.8% after 3 days of culture). In conclusion, calcium dobesilate inhibited choroidal explant angiogenesis both in vitro and ex vivo. This effect may be due, at least in part, to inhibition of VEGF production. Antiangiogenesis by calcium dobesilate can be involved in its therapeutic benefit in diabetic retinopathy.

  5. Optimized extraction of calcium malate from eggshell treated by PEF and an absorption assessment in vitro. (United States)

    Lin, Songyi; Wang, Liyan; Jones, Gregory; Trang, Hung; Yin, Yongguang; Liu, Jingbo


    Under optimized pulsed electric field (PEF) treatment for production of eggshell calcium malate (ESCM) by one-factor-at-a-time test and ternary quadratic regression orthogonal combination design (TQROCD), an absorption assessment of ESCM treated by the best conditions of PEF were performed in male mice with apparent calcium absorption rate (ACAR), serum alkalinity phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP), serum calcium and serum phosphorus, length of femurs and skeletal calcium content were studied. The highest dissoluble calcium malate content (7.075 mg/mL) was obtained with the 6.0% malic acid, the electric field intensity of 20 kV/cm, and pulse duration of 24 μs. In vitro, ESCM prepared by the best conditions of PEF at doses of 133.0 mg kg(-1) d(-1) for 70 d not only significantly improve the ALP activity, the femur length and calcium content of bone of the mice (PPEF could be taken as a highly effective, environmentally friendly and energy-saving method for preparation of ESCM, which treated by PEF could promote the absorption of calcium in vitro, extraordinary can promote bone development and a healthy bone. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Morphological Investigation of Calcium Carbonate during Ammonification-Carbonization Process of Low Concentration Calcium Solution


    Huaigang Cheng; Xiaoxi Zhang; Huiping Song


    Ultrafine calcium carbonate is a widely used cheap additive. The research is conducted in low degree supersaturation solution in order to study the polymorphic phases’ change and its factors of the calcium carbonate precipitate in the ammonification-carbonization process of the solution with calcium. Fine particles of calcium carbonate are made in the solution containing 0.015 mol/L of Ca2+. Over 98% of the calcium carbonate precipitate without ammonification resembles the morphology of calci...

  7. 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


    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...

  8. Renin release from permeabilized juxtaglomerular cells is stimulated by chloride but not by low calcium

    DEFF Research Database (Denmark)

    Jensen, B L; Skøtt, O


    The intracellular concentrations of calcium and chloride have been suggested to be involved in the control of renin secretion from juxtaglomerular (JG) cells. We have tested these propositions on permeabilized JG cells. Rat glomeruli with attached JG cells were isolated by the magnetic iron......M]. These maneuvers had no effect on renin release, while 1.5 mM calcium caused a stimulation, which was not inhibited by 50 mM sucrose. Isosmotic increases in the chloride concentration to 25, 60, and 132 mM resulted in prompt stimulations of renin release. Similarly, iodide and nitrate stimulated renin release. We...... conclude that renin release from permeabilized JG cells is unaffected by calcium concentrations in the nano- and micromolar range, while the release is stimulated by chloride or other permeant anions. We suggest that in intact JG cells an increase in calcium inhibits renin release through activation...

  9. Salivary calcium concentration as a screening tool for postmenopausal osteoporosis. (United States)

    Rabiei, Maryam; Masooleh, Irandokht Shenavar; Leyli, Ehsan Kazemnejad; Nikoukar, Laia Rahbar


    Measurements of salivary calcium level may be a useful screening tool for osteoporosis in postmenopausal women. The purpose of this study was to clarify whether this measure is valid compared with dual-energy X-ray (Bone Mineral Density) screening tools in osteoporosis. A case-control study was carried out in 40 postmenopausal women with osteoporosis (T-score ≤ -2.5) and 40 women without osteoporosis (T-score > -1 bone mineral density). Salivary samples were collected and calcium concentrations were measured and expressed as mg/dL. Receiver operating characteristic curve analyses was used to determine the optimal cut-off thresholds for salivary calcium in healthy postmenopausal women. The cut-off point for salivary calcium was 6.1 mg/dL. The sensitivity and specificity, respectively, for identifying women with osteoporosis, were 67.5 (95%CI 52.33-82.67) and 60% (95%CI 44.62-75.38). The area under curve (AUC) was 0.678 (95%CI 0.56-0.79), the positive predictive value (PPV) was 62.79 (95%CI 47.74-77.84) and negative predictive value (NPV) was 64.86% (95%CI 49.27-80.46). The positive likelihood ratio was 1.688 and the negative likelihood ratio was 0.542. Salivary calcium concentration discriminates between women with and without osteoporosis and constitutes a useful tool for screening for osteoporosis. © 2012 The Authors International Journal of Rheumatic Diseases © 2012 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

  10. Mammary-Specific Ablation of the Calcium-Sensing Receptor During Lactation Alters Maternal Calcium Metabolism, Milk Calcium Transport, and Neonatal Calcium Accrual (United States)

    Mamillapalli, Ramanaiah; VanHouten, Joshua; Dann, Pamela; Bikle, Daniel; Chang, Wenhan; Brown, Edward


    To meet the demands for milk calcium, the lactating mother adjusts systemic calcium and bone metabolism by increasing dietary calcium intake, increasing bone resorption, and reducing renal calcium excretion. As part of this adaptation, the lactating mammary gland secretes PTHrP into the maternal circulation to increase bone turnover and mobilize skeletal calcium stores. Previous data have suggested that, during lactation, the breast relies on the calcium-sensing receptor (CaSR) to coordinate PTHrP secretion and milk calcium transport with calcium availability. To test this idea genetically, we bred BLG-Cre mice with CaSR-floxed mice to ablate the CaSR specifically from mammary epithelial cells only at the onset of lactation (CaSR-cKO mice). Loss of the CaSR in the lactating mammary gland did not disrupt alveolar differentiation or milk production. However, it did increase the secretion of PTHrP into milk and decreased the transport of calcium from the circulation into milk. CaSR-cKO mice did not show accelerated bone resorption, but they did have a decrease in bone formation. Loss of the mammary gland CaSR resulted in hypercalcemia, decreased PTH secretion, and increased renal calcium excretion in lactating mothers. Finally, loss of the mammary gland CaSR resulted in decreased calcium accrual by suckling neonates, likely due to the combination of increased milk PTHrP and decreased milk calcium. These results demonstrate that the mammary gland CaSR coordinates maternal bone and calcium metabolism, calcium transport into milk, and neonatal calcium accrual during lactation. PMID:23782944

  11. Effects of caffeine on calcium release from the sarcoplasmic reticulum in frog skeletal muscle fibres. (United States)

    Klein, M G; Simon, B J; Schneider, M F


    1. Resting myoplasmic [Ca2+] and [Ca2+] transients (delta [Ca2+]) were monitored using Fura-2 fluorescence and Antipyrylazo III absorbance signals from voltage-clamped segments of cut frog skeletal muscle fibres in the presence and absence of 0.5 mM-caffeine. The rate of release (Rrel) of calcium from the sarcoplasmic reticulum was calculated from delta [Ca2+]. 2. delta [Ca2+] and Rrel were increased in caffeine for all pulses. The decline of delta [Ca2+] was slower after a given pulse in caffeine than without caffeine. Resting [Ca2+] was slightly elevated in caffeine. 3. The voltage dependence of the peak value of Rrel and of the steady level of Rrel at the end of a 60-120 ms pulse were both shifted towards more negative voltages in caffeine. For relatively small pulses the voltage at which a given release waveform was observed was also shifted to more negative voltages. 4. Intramembrane charge movements measured in the same fibres in which the above changes in Rrel were observed showed no significant changes in caffeine. 5. In caffeine calcium release continued for many milliseconds after the end of a short (10 ms) pulse. Continued release after a pulse was not observed without caffeine and was probably due to positive feedback of elevated [Ca2+] on calcium release resulting from calcium-induced calcium release in caffeine. 6. Intramembrane charge movements after short pulses showed no change in caffeine that could account for the continued calcium release after the pulse. 7. Continued release after short pulses in caffeine decreased as the pulse duration was increased and was absent for pulses of 60 ms or longer. Rrel also inactivated during such pulses. 8. Relatively large and long conditioning pulses in caffeine suppressed both the peak Rrel and the continued release after short pulses. Peak release and continued release after short pulses recovered in parallel with increasing recovery time following suppression by a conditioning pulse in caffeine. 9. These

  12. Apatite Formation from Amorphous Calcium Phosphate and Mixed Amorphous Calcium Phosphate/Amorphous Calcium Carbonate. (United States)

    Ibsen, Casper J S; Chernyshov, Dmitry; Birkedal, Henrik


    Crystallization from amorphous phases is an emerging pathway for making advanced materials. Biology has made use of amorphous precursor phases for eons and used them to produce structures with remarkable properties. Herein, we show how the design of the amorphous phase greatly influences the nanocrystals formed therefrom. We investigate the transformation of mixed amorphous calcium phosphate/amorphous calcium carbonate phases into bone-like nanocrystalline apatite using in situ synchrotron X-ray diffraction and IR spectroscopy. The speciation of phosphate was controlled by pH to favor HPO4 (2-) . In a carbonate free system, the reaction produces anisotropic apatite crystallites with large aspect ratios. The first formed crystallites are highly calcium deficient and hydrogen phosphate rich, consistent with thin octacalcium phosphate (OCP)-like needles. During growth, the crystallites become increasingly stoichiometric, which indicates that the crystallites grow through addition of near-stoichiometric apatite to the OCP-like initial crystals through a process that involves either crystallite fusion/aggregation or Ostwald ripening. The mixed amorphous phases were found to be more stable against phase transformations, hence, the crystallization was inhibited. The resulting crystallites were smaller and less anisotropic. This is rationalized by the idea that a local phosphate-depletion zone formed around the growing crystal until it was surrounded by amorphous calcium carbonate, which stopped the crystallization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Computational study of a calcium release-activated calcium channel (United States)

    Talukdar, Keka; Shantappa, Anil


    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.

  14. The Calcium Wave of Vegetable Cells

    Directory of Open Access Journals (Sweden)

    TD. Geydan


    Full Text Available Calcium is an essential nutrient for plants; it is involved in developmental processes and in responses to biotic and abiotic factors. Several signals that modify the calcium concentration in the cytoplasm, endoplasmic reticulum, nucleus and/or plastids have been observed. These changes in the calcium concentration in the cell interior are rapidly returned to basal levels, in the meantime, innumerable and complex signaling cascades. This note exposes the mechanisms of calcium transport through the cell membranes of the entrance of calcium in the plant cells.

  15. '60

    African Journals Online (AJOL)

    travail; même pour une affaire privée, il fallait être allié au pouvoir ou verser des pots de vins. L'on ne peut par .... Elle permet également d'impliquer une grande partie de la population au pouvoir et de la rendre responsable ... sport, développement rural, économie, droits de la femme, jeunesse,...C'est maintenant ce comité ...

  16. BRIC-60: Biological Research in Canisters (BRIC)-60 (United States)

    Richards, Stephanie E. (Compiler); Levine, Howard G.; Romero, Vergel


    The Biological Research in Canisters (BRIC) is an anodized-aluminum cylinder used to provide passive stowage for investigations evaluating the effects of space flight on small organisms. Specimens flown in the BRIC 60 mm petri dish (BRIC-60) hardware include Lycoperscion esculentum (tomato), Arabidopsis thaliana (thale cress), Glycine max (soybean) seedlings, Physarum polycephalum (slime mold) cells, Pothetria dispar (gypsy moth) eggs and Ceratodon purpureus (moss).

  17. Exopolysaccharides regulate calcium flow in cariogenic biofilms. (United States)

    Astasov-Frauenhoffer, Monika; Varenganayil, Muth M; Decho, Alan W; Waltimo, Tuomas; Braissant, Olivier


    Caries-associated biofilms induce loss of calcium from tooth surfaces in the presence of dietary carbohydrates. Exopolysaccharides (EPS) provide a matrix scaffold and an abundance of primary binding sites within biofilms. The role of EPS in binding calcium in cariogenic biofilms is only partially understood. Thus, the aim of the present study is to investigate the relationship between the calcium dissolution rates and calcium tolerance of caries-associated bacteria and yeast as well as to examine the properties of EPS to quantify its binding affinity for dissolved calcium. Calcium dissolution was measured by dissolution zones on Pikovskaya's agar. Calcium tolerance was assessed by isothermal microcalorimetry (IMC) by adding CaCl2 to the bacterial cultures. Acid-base titration and Fourier transform infrared (FTIR) spectroscopy were used to identify possible functional groups responsible for calcium binding, which was assessed by isothermal titration calorimetry (ITC). Lactobacillus spp. and mutans streptococci demonstrated calcium dissolution in the presence of different carbohydrates. All strains that demonstrated high dissolution rates also revealed higher rates of calcium tolerance by IMC. In addition, acidic functional groups were predominantly identified as possible binding sites for calcium ions by acid-base titration and FTIR. Finally, ITC revealed EPS to have a higher binding affinity for calcium compared, for example, to lactic acid. In conclusion, this study illustrates the role of EPS in terms of the calcium tolerance of cariogenic microbiota by determining the ability of EPS to control free calcium concentrations within the biofilms as a self-regulating mode of action in the pathogenesis of dental caries.

  18. Exopolysaccharides regulate calcium flow in cariogenic biofilms.

    Directory of Open Access Journals (Sweden)

    Monika Astasov-Frauenhoffer

    Full Text Available Caries-associated biofilms induce loss of calcium from tooth surfaces in the presence of dietary carbohydrates. Exopolysaccharides (EPS provide a matrix scaffold and an abundance of primary binding sites within biofilms. The role of EPS in binding calcium in cariogenic biofilms is only partially understood. Thus, the aim of the present study is to investigate the relationship between the calcium dissolution rates and calcium tolerance of caries-associated bacteria and yeast as well as to examine the properties of EPS to quantify its binding affinity for dissolved calcium. Calcium dissolution was measured by dissolution zones on Pikovskaya's agar. Calcium tolerance was assessed by isothermal microcalorimetry (IMC by adding CaCl2 to the bacterial cultures. Acid-base titration and Fourier transform infrared (FTIR spectroscopy were used to identify possible functional groups responsible for calcium binding, which was assessed by isothermal titration calorimetry (ITC. Lactobacillus spp. and mutans streptococci demonstrated calcium dissolution in the presence of different carbohydrates. All strains that demonstrated high dissolution rates also revealed higher rates of calcium tolerance by IMC. In addition, acidic functional groups were predominantly identified as possible binding sites for calcium ions by acid-base titration and FTIR. Finally, ITC revealed EPS to have a higher binding affinity for calcium compared, for example, to lactic acid. In conclusion, this study illustrates the role of EPS in terms of the calcium tolerance of cariogenic microbiota by determining the ability of EPS to control free calcium concentrations within the biofilms as a self-regulating mode of action in the pathogenesis of dental caries.

  19. Lithium prevents early cytosolic calcium increase and secondary injurious calcium overload in glycolytically inhibited endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Bosche, Bert, E-mail: [Department of Neurology, University of Duisburg-Essen (Germany); Max Planck Institute for Neurological Research with Klaus-Joachim-Zülch Laboratories of the Max Planck Society and the Medical Faculty of the University of Cologne (Germany); Schäfer, Matthias, E-mail: [Institute of Physiology, Justus-Liebig-University Giessen (Germany); Graf, Rudolf, E-mail: [Max Planck Institute for Neurological Research with Klaus-Joachim-Zülch Laboratories of the Max Planck Society and the Medical Faculty of the University of Cologne (Germany); Härtel, Frauke V., E-mail: [Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden (Germany); Schäfer, Ute, E-mail: [Research Unit for Experimental Neurotraumatology, Medical University of Graz (Austria); Noll, Thomas, E-mail: [Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden (Germany)


    Highlights: •We investigate free calcium as a central signalling element in endothelial cells. •Inhibition of glycolysis with 2-deoxy-D-glucose reduces cellular ATP. •This manoeuvre leads to a biphasic increase and overload of free calcium. •Pre-treatment with lithium for 24 h abolishes both phases of the calcium increase. •This provides a new strategy to protect endothelial calcium homeostasis and barrier function. -- Abstract: Cytosolic free calcium concentration ([Ca{sup 2+}]{sub i}) is a central signalling element for the maintenance of endothelial barrier function. Under physiological conditions, it is controlled within narrow limits. Metabolic inhibition during ischemia/reperfusion, however, induces [Ca{sup 2+}]{sub i} overload, which results in barrier failure. In a model of cultured porcine aortic endothelial monolayers (EC), we addressed the question of whether [Ca{sup 2+}]{sub i} overload can be prevented by lithium treatment. [Ca{sup 2+}]{sub i} and ATP were analysed using Fura-2 and HPLC, respectively. The combined inhibition of glycolytic and mitochondrial ATP synthesis by 2-desoxy-D-glucose (5 mM; 2-DG) plus sodium cyanide (5 mM; NaCN) caused a significant decrease in cellular ATP content (14 ± 1 nmol/mg protein vs. 18 ± 1 nmol/mg protein in the control, n = 6 culture dishes, P < 0.05), an increase in [Ca{sup 2+}]{sub i} (278 ± 24 nM vs. 71 ± 2 nM in the control, n = 60 cells, P < 0.05), and the formation of gaps between adjacent EC. These observations indicate that there is impaired barrier function at an early state of metabolic inhibition. Glycolytic inhibition alone by 10 mM 2-DG led to a similar decrease in ATP content (14 ± 2 nmol/mg vs. 18 ± 1 nmol/mg in the control, P < 0.05) with a delay of 5 min. The [Ca{sup 2+}]{sub i} response of EC was biphasic with a peak after 1 min (183 ± 6 nM vs. 71 ± 1 nM, n = 60 cells, P < 0.05) followed by a sustained increase in [Ca{sup 2+}]{sub i}. A 24-h pre-treatment with 10 mM of lithium

  20. Calcium precipitate induced aerobic granulation. (United States)

    Wan, Chunli; Lee, Duu-Jong; Yang, Xue; Wang, Yayi; Wang, Xingzu; Liu, Xiang


    Aerobic granulation is a novel biotechnology for wastewater treatment. This study refined existing aerobic granulation mechanisms as a sequencing process including formation of calcium precipitate under alkaline pH to form inorganic cores, followed by bacterial attachment and growth on these cores to form the exopolysaccharide matrix. Mature granules comprised an inner core and a matrix layer and a rim layer with enriched microbial strains. The inorganic core was a mix of different crystals of calcium and phosphates. Functional strains including Sphingomonas sp., Paracoccus sp. Sinorhizobium americanum strain and Flavobacterium sp. attached onto the cores. These functional strains promote c-di-GMP production and the expression by Psl and Alg genes for exopolysaccharide production to enhance formation of mature granules. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. 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


    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....

  2. Calcium intake is not associated with increased coronary artery calcification: the Framingham Study. (United States)

    Samelson, Elizabeth J; Booth, Sarah L; Fox, Caroline S; Tucker, Katherine L; Wang, Thomas J; Hoffmann, Udo; Cupples, L Adrienne; O'Donnell, Christopher J; Kiel, Douglas P


    Adequate calcium intake is known to protect the skeleton. However, studies that have reported adverse effects of calcium supplementation on vascular events have raised widespread concern. We assessed the association between calcium intake (from diet and supplements) and coronary artery calcification, which is a measure of atherosclerosis that predicts risk of ischemic heart disease independent of other risk factors. This was an observational, prospective cohort study. Participants included 690 women and 588 men in the Framingham Offspring Study (mean age: 60 y; range: 36-83 y) who attended clinic visits and completed food-frequency questionnaires in 1998-2001 and underwent computed tomography scans 4 y later in 2002-2005. The mean age-adjusted coronary artery-calcification Agatston score decreased with increasing total calcium intake, and the trend was not significant after adjustment for age, BMI, smoking, alcohol consumption, vitamin D-supplement use, energy intake, and, for women, menopause status and estrogen use. Multivariable-adjusted mean Agatston scores were 2.36, 2.52, 2.16, and 2.39 (P-trend = 0.74) with an increasing quartile of total calcium intake in women and 4.32, 4.39, 4.19, and 4.37 (P-trend = 0.94) in men, respectively. Results were similar for dietary calcium and calcium supplement use. Our study does not support the hypothesis that high calcium intake increases coronary artery calcification, which is an important measure of atherosclerosis burden. The evidence is not sufficient to modify current recommendations for calcium intake to protect skeletal health with respect to vascular calcification risk.

  3. Involvement of T1R3 in calcium-magnesium taste. (United States)

    Tordoff, Michael G; Shao, Hongguang; Alarcón, Laura K; Margolskee, Robert F; Mosinger, Bedrich; Bachmanov, Alexander A; Reed, Danielle R; McCaughey, Stuart


    Calcium and magnesium are essential for survival but it is unknown how animals detect and consume enough of these minerals to meet their needs. To investigate this, we exploited the PWK/PhJ (PWK) strain of mice, which, in contrast to the C57BL/6J (B6) and other inbred strains, displays strong preferences for calcium solutions. We found that the PWK strain also has strong preferences for MgCl2 and saccharin solutions but not representative salty, sour, bitter, or umami taste compounds. A genome scan of B6 x PWK F2 mice linked a component of the strain difference in calcium and magnesium preference to distal chromosome 4. The taste receptor gene, Tas1r3, was implicated by studies with 129.B6ByJ-Tas1r3 congenic and Tas1r3 knockout mice. Most notably, calcium and magnesium solutions that were avoided by wild-type B6 mice were preferred (relative to water) by B6 mice null for the Tas1r3 gene. Oral calcium elicited less electrophysiological activity in the chorda tympani nerve of Tas1r3 knockout than wild-type mice. Comparison of the sequence of Tas1r3 with calcium and saccharin preferences in inbred mouse strains found 1) an inverse correlation between calcium and saccharin preference scores across primarily domesticus strains, which was associated with an I60T substitution in T1R3, and 2) a V689A substitution in T1R3 that was unique to the PWK strain and thus may be responsible for its strong calcium and magnesium preference. Our results imply that, in addition to its established roles in the detection of sweet and umami compounds, T1R3 functions as a gustatory calcium-magnesium receptor.

  4. A Closer look at calcium absorption and the benefits and risks of dietary versus supplemental calcium. (United States)

    Booth, Anna; Camacho, Pauline


    To perform a thorough search of the literature on calcium research and specifically address the topic of calcium absorption. PubMed and Ovid were the main engines used for primary literature searches; textbooks, review articles, and book chapters are examples of the other sources used for supplemental information. Regarding calcium absorption, it seems apparent that the absorption efficiency of all calcium salts, regardless of solubility, is fairly equivalent and not significantly less than the absorption efficiency of dietary calcium. However, dietary calcium has been shown to have greater impact in bone building than supplemental calcium. This is likely due to improved absorption with meals and the tendency of people to intake smaller amounts more frequently, which is more ideal for the body's method of absorption. In addition, the cardiovascular risks of excessive calcium intake appear to be more closely related to calcium supplements than dietary calcium; this relationship continues to be controversial in the literature. We conclude that further studies are needed for direct comparison of supplemental and dietary calcium to fully establish if one is superior to the other with regard to improving bone density. We also propose further studies on the cardiovascular risk of long-term increased calcium intake and on physician estimates of patients' daily calcium intake to better pinpoint those patients who require calcium supplementation.

  5. Treatment of calcium dobesilate tablets capsules combined yimaikang for retinal vein occlusion

    Directory of Open Access Journals (Sweden)

    Hui-Juan Zheng


    Full Text Available AIM: To observe the clinical curative effect of calcium dobesilate capsule and yimaikang tablet for treating retinal vein occlusion(RVO. METHODS:A total of 120 patients(167 eyeswith RVO were divided into 2 groups at random. The control group of 60 cases(82 eyeswere given calcium dobesilate capsule, and the treatment group of 60 cases(85 eyesreceived calcium dobesilate capsule and yimaikang tablet. Changes of visual acuity and clinical effects after 3 courses of treatment were compared and analyzed for all patients. RESULTS: Markedly effective 15 cases(23 eyes, effective 42 cases(57 eyesand invalid 3 cases(5 eyesin the 60 cases(85 eyesof the treatment group, the total effective rate was 94.1%. Eighty-two eyes of 60 cases in the control group, markedly effective in 8 cases(12 eyes, effective 38 cases(49 eyes, ineffective 14 cases(21 eyes, The total effective rate was 74.4% in the control group. There were significant differences between the 2 groups of curative effect, and low incidence rate of adverse reaction. CONCLUSION: Calcium dobesilate capsules and yimaikang tablet is effective and safe in the treatment of RVO.

  6. CCN3 and calcium signaling

    Directory of Open Access Journals (Sweden)

    Li Chang Long


    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.

  7. Kinetics of calcium sulfoaluminate formation from tricalcium aluminate, calcium sulfate and calcium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xuerun, E-mail:; Zhang, Yu; Shen, Xiaodong, E-mail:; Wang, Qianqian; Pan, Zhigang


    The formation kinetics of tricalcium aluminate (C{sub 3}A) and calcium sulfate yielding calcium sulfoaluminate (C{sub 4}A{sub 3}$) and the decomposition kinetics of calcium sulfoaluminate were investigated by sintering a mixture of synthetic C{sub 3}A and gypsum. The quantitative analysis of the phase composition was performed by X-ray powder diffraction analysis using the Rietveld method. The results showed that the formation reaction 3Ca{sub 3}Al{sub 2}O{sub 6} + CaSO{sub 4} → Ca{sub 4}Al{sub 6}O{sub 12}(SO{sub 4}) + 6CaO was the primary reaction < 1350 °C with and activation energy of 231 ± 42 kJ/mol; while the decomposition reaction 2Ca{sub 4}Al{sub 6}O{sub 12}(SO{sub 4}) + 10CaO → 6Ca{sub 3}Al{sub 2}O{sub 6} + 2SO{sub 2} ↑ + O{sub 2} ↑ primarily occurred beyond 1350 °C with an activation energy of 792 ± 64 kJ/mol. The optimal formation region for C{sub 4}A{sub 3}$ was from 1150 °C to 1350 °C and from 6 h to 1 h, which could provide useful information on the formation of C{sub 4}A{sub 3}$ containing clinkers. The Jander diffusion model was feasible for the formation and decomposition of calcium sulfoaluminate. Ca{sup 2+} and SO{sub 4}{sup 2−} were the diffusive species in both the formation and decomposition reactions. -- Highlights: •Formation and decomposition of calcium sulphoaluminate were studied. •Decomposition of calcium sulphoaluminate combined CaO and yielded C{sub 3}A. •Activation energy for formation was 231 ± 42 kJ/mol. •Activation energy for decomposition was 792 ± 64 kJ/mol. •Both the formation and decomposition were controlled by diffusion.

  8. The Role of Calcium in Osteoporosis (United States)

    Arnaud, C. D.; Sanchez, S. D.


    Calcium requirements may vary throughout the lifespan. During the growth years and up to age 25 to 30, it is important to maximize dietary intake of calcium to maintain positive calcium balance and achieve peak bone mass, thereby possibly decreasing the risk of fracture when bone is subsequently lost. Calcium intake need not be greater than 800 mg/day during the relatively short period of time between the end of bone building and the onset of bone loss (30 to 40 years). Starting at age 40 to 50, both men and women lose bone slowly, but women lose bone more rapidly around the menopause and for about 10 years after. Intestinal calcium absorption and the ability to adapt to low calcium diets are impaired in many postmenopausal women and elderly persons owing to a suspected functional or absolute decrease in the ability of the kidney to produce 1,25(OH)2D2. The bones then become more and more a source of calcium to maintain critical extracellular fluid calcium levels. Excessive dietary intake of protein and fiber may induce significant negative calcium balance and thus increase dietary calcium requirements. Generally, the strongest risk factors for osteoporosis are uncontrollable (e.g., sex, age, and race) or less controllable (e.g., disease and medications). However, several factors such as diet, physical activity, cigarette smoking, and alcohol use are lifestyle related and can be modified to help reduce the risk of osteoporosis.

  9. Assessment of calcium intake by adolescents

    Directory of Open Access Journals (Sweden)

    Cristiane Franco de Oliveira


    Full Text Available OBJECTIVE: To evaluate the daily calcium intake of adolescents in schools from Chapecó, Santa Catarina, Southern Brazil, to check if calcium intake is in accordance with the Dietary Reference Intakes (DRI, and to investigate variables associated with daily calcium intake.METHODS: Cross-sectional study approved by the Institutional Review Board and developed in 2010. Students of the 8th grade completed questionnaires with personal data and questions about the calcium-rich foods intake frequency. In order to compare students with adequate (1300mg or inadequate intake of calcium/day (<1300mg, parametric and nonparametric tests were used.RESULTS: A total of 214 students with a mean age of 14.3±1.0 years were enrolled. The median daily calcium intake was 540mg (interquartile range - IQ: 312-829mg and only 25 students (11.7% had calcium intake within the recommendations of the DRI for age. Soft drink consumption ≥3 times/week was associated with a lower intake of calcium.CONCLUSIONS: Few students ingested adequate levels of calcium for the age group. It is necessary to develop a program to encourage a greater intake of calcium-rich foods in adolescence.

  10. The Risks and Benefits of Calcium Supplementation

    Directory of Open Access Journals (Sweden)

    Chan Soo Shin


    Full Text Available The association between calcium supplementation and adverse cardiovascular events has recently become a topic of debate due to the publication of two epidemiological studies and one meta-analysis of randomized controlled clinical trials. The reports indicate that there is a significant increase in adverse cardiovascular events following supplementation with calcium; however, a number of experts have raised several issues with these reports such as inconsistencies in attempts to reproduce the findings in other populations and questions concerning the validity of the data due to low compliance, biases in case ascertainment, and/or a lack of adjustment. Additionally, the Auckland Calcium Study, the Women's Health Initiative, and many other studies included in the meta-analysis obtained data from calcium-replete subjects and it is not clear whether the same risk profile would be observed in populations with low calcium intakes. Dietary calcium intake varies widely throughout the world and it is especially low in East Asia, although the risk of cardiovascular events is less prominent in this region. Therefore, clarification is necessary regarding the occurrence of adverse cardiovascular events following calcium supplementation and whether this relationship can be generalized to populations with low calcium intakes. Additionally, the skeletal benefits from calcium supplementation are greater in subjects with low calcium intakes and, therefore, the risk-benefit ratio of calcium supplementation is likely to differ based on the dietary calcium intake and risks of osteoporosis and cardiovascular diseases of various populations. Further studies investigating the risk-benefit profiles of calcium supplementation in various populations are required to develop population-specific guidelines for individuals of different genders, ages, ethnicities, and risk profiles around the world.

  11. What is C60. C60 no shotai wa

    Energy Technology Data Exchange (ETDEWEB)

    Osawa, E. (Toyohashi University of Technology, Aichi (Japan))


    This paper elucidates what C60 really is. C60(1) is a carbon cluster of a special structure with Cs bonded solidly, and is a molecule chemically. Sixty Sp[sup 2] mixed carbon atoms are distributed evenly on a sphere with a radius of 7[angstrom]. Molecules in a crystal are of nearly perfect sphere, with small inter-molecular contact and weak binding force, and spinning at more than one billion rotations per second. C60 is a carbon's fourth allotrope. Three types of modification have been known to date, including the rugby ball shaped fullerene. Fullerene has been studied actively resulting in successive new reports. It is manufactured basically using the Kraetchmer's resistive heating method at a yield of approximately 10%. A plasma discharge process and an improved laser irradiation process can raise the yield to as high as 20% or more. Industrial application of C60 is within reach. Developmental researches are being moved forward by private corporations in Japan. Its application may cover wide areas, including electric conductors, semiconductors and the like. Elucidation of its production mechanisms has been waited for, together with solving a problem of reducing C60 reagent price. 45 refs., 3 figs.


    Directory of Open Access Journals (Sweden)

    V. N. Khodyrev


    Full Text Available Aim:  To assess the providing an organism with vitamins (А, В2, С, Е, β-carotene, and calcium in osteoporosis patients by measuring their intake and plasma concentrations. Materials and methods: 108 pairs “osteoporosis patient – healthy volunteer” aged 64.29±9.73 years were formed using a “case-control” method. Real intake of vitamins and calcium was studied defining the frequency of food taking for a month using questionnaire method. Daily intake of vitamins А, В2, С, Е, β-carotene, and calcium was calculated based on the analysis of the frequency of food taking. Among the basic group, using randomized method, 60% of osteoporosis patients were selected who underwent definition of plasma levels of vitamins А, В2, С, and Е. The same study was performed in 60 control volunteers. Results: Correlation of the intake of vitamins A, C, and β-carotene with their plasma levels wasn’t noted. It may reveal an increased need in these nutrients in osteoporosis. According to the calcium intake, every osteoporosis patient can be attributed to a population category with deep insufficiency of calcium intake (less than 500 mg a day. Conclusion: The data obtained need further investigation and, first of all, in clinical and biochemical fields (enzymatic non-provision for calcium uptake, clinical manifestations of insufficient provision with nutrients. Solution of these problems would enable regulation of food intake concerning calcium uptake in osteoporosis.

  13. Influence of colloidal calcium phosphate level on the microstructure and rheological properties of rennet-induced skim milk gels

    DEFF Research Database (Denmark)

    Koutina, Glykeria; Knudsen, Jes Christian; Andersen, Ulf


    Colloidal calcium phosphate is an essential part of casein micelles and being responsible for their stability. Different mineralization of casein micelles was obtained by acidification of skim milk to pH 6.5, 6.0 or 5.5, followed by a dialysis method, using simulated milk ultrafiltrate without...... lactose, to obtain varying levels of micellar calcium and phosphorus but constant value of pH, serum and free calcium, and serum phosphorus. Bovine chymosin was added to the skim milk samples after dialysis and microstructural and rheological properties during gel formation were recorded at 30°C. Samples...

  14. Calcium signals can freely cross the nuclear envelope in hippocampal neurons: somatic calcium increases generate nuclear calcium transients


    Eder, Anja; Bading, Hilmar


    Abstract Background In hippocampal neurons, nuclear calcium signaling is important for learning- and neuronal survival-associated gene expression. However, it is unknown whether calcium signals generated by neuronal activity at the cell membrane and propagated to the soma can unrestrictedly cross the nuclear envelope to invade the nucleus. The nuclear envelope, which allows ion transit via the nuclear pore complex, may represent a barrier for calcium and has been suggested to insulate the nuc...

  15. Superconducting Continuous Graphene Fibers via Calcium Intercalation. (United States)

    Liu, Yingjun; Liang, Hui; Xu, Zhen; Xi, Jiabin; Chen, Genfu; Gao, Weiwei; Xue, Mianqi; Gao, Chao


    Superconductors are important materials in the field of low-temperature magnet applications and long-distance electrical power transmission systems. Besides metal-based superconducting materials, carbon-based superconductors have attracted considerable attention in recent years. Up to now, five allotropes of carbon, including diamond, graphite, C60, CNTs, and graphene, have been reported to show superconducting behavior. However, most of the carbon-based superconductors are limited to small size and discontinuous phases, which inevitably hinders further application in macroscopic form. Therefore, it raises a question of whether continuously carbon-based superconducting wires could be accessed, which is of vital importance from viewpoints of fundamental research and practical application. Here, inspired by superconducting graphene, we successfully fabricated flexible graphene-based superconducting fibers via a well-established calcium (Ca) intercalation strategy. The resultant Ca-intercalated graphene fiber (Ca-GF) shows a superconducting transition at ∼11 K, which is almost 2 orders of magnitude higher than that of early reported alkali metal intercalated graphite and comparable to that of commercial superconducting NbTi wire. The combination of lightness and easy scalability makes Ca-GF highly promising as a lightweight superconducting wire.

  16. Hydrophobic Calcium Carbonate for Cement Surface

    Directory of Open Access Journals (Sweden)

    Shashi B. Atla


    Full Text Available This report describes a novel way to generate a highly effective hydrophobic cement surface via a carbonation route using sodium stearate. Carbonation reaction was carried out at different temperatures to investigate the hydrophobicity and morphology of the calcium carbonate formed with this process. With increasing temperatures, the particles changed from irregular shapes to more uniform rod-like structures and then aggregated to form a plate-like formation. The contact angle against water was found to increase with increasing temperature; after 90 °C there was no further increase. The maximum contact angle of 129° was obtained at the temperature of 60 °C. It was also found that carbonation increased the micro hardness of the cement material. The micro hardness was found to be dependent on the morphology of the CaCO3 particles. The rod like structures which caused increased mineral filler produced a material with enhanced strength. The 13C cross polarization magic-angle spinning NMR spectra gave plausible explanation of the interaction of organic-inorganic moieties.

  17. Biodiesel production through transesterification over natural calciums

    Energy Technology Data Exchange (ETDEWEB)

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


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

  18. Calcium gluconate supplementation is effective to balance calcium homeostasis in patients with gastrectomy. (United States)

    Krause, M; Keller, J; Beil, B; van Driel, I; Zustin, J; Barvencik, F; Schinke, T; Amling, M


    We demonstrate histological evidence for hyperparathyroidism in patients with gastrectomy. This is, at least in part, explained by impaired calcium absorption, resulting in mineralization defects and secondary hyperparathyroidism. Additionally, we demonstrate improved bone mineralization in patients with gastrectomy after gluconate therapy and showed the effectiveness of calcium gluconate over carbonate to balance impaired calcium hemostasis in mice. Gastrectomy and hypochlorhydria due to long-term proton pump inhibitor therapy are associated with increased fracture risk because of intestinal calcium malabsorption. Hence, our objectives were to histologically investigate bone metabolism in patients with gastrectomy and to analyze the impact of calcium gluconate supplementation on skeletal integrity in the setting of impaired gastric acidification. Undecalcified bone biopsies of 26 gastrectomized individuals were histologically analyzed. In the clinical setting, we retrospectively identified 5 gastrectomized patients with sufficient vitamin D level, who were additionally supplemented with calcium gluconate and had a real bone mineral density (aBMD) follow-up assessments. A mouse model of achlorhydria (ATP4b-/-) was used to compare the effect of calcium gluconate and calcium carbonate supplementation on bone metabolism. Biopsies from gastrectomized individuals showed significantly increased osteoid, osteoclast, and osteoblast indices and fibroosteoclasia (p < 0.05) as well as impaired calcium distribution in mineralized bone matrix compared to healthy controls. Five gastrectomized patients with sufficient vitamin D level demonstrated a significant increase in aBMD after a treatment with calcium gluconate alone for at least 6 months (p < 0.05). Calcium gluconate was superior to calcium carbonate in maintaining calcium metabolism in a mouse model of achlorhydria. Gastrectomy is associated with severe osteomalacia, marrow fibrosis, and impaired calcium distribution

  19. Influence of calcium sources on microbially induced calcium carbonate precipitation by Bacillus sp. CR2. (United States)

    Achal, Varenyam; Pan, Xiangliang


    Stimulation of microbially induced calcium carbonate precipitation (MICCP) is likely to be influenced by calcium sources. In order to study such influences, we performed MICCP using Bacillus sp. CR2 in nutrient broth containing urea, supplemented with different calcium sources (calcium chloride, calcium oxide, calcium acetate and calcium nitrate). The experiment lasted 7 days, during which bacterial growth, urease activity, calcite production and pH were measured. Our results showed that calcium chloride is the better calcium source for MICCP process, since it provides higher urease activity and more calcite production. The influences of calcium sources on MICCP were further studied using Fourier transform-infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. These analyses confirmed that the precipitate formed was CaCO3 and composed of predominantly calcite crystals with a little amount of aragonite and vaterite crystals. The maximum yield of calcite precipitation was achievable with calcium chloride followed by calcium nitrate as a calcium source. The results of present study may be applicable to media preparation during efficient MICCP process.

  20. Calcium signals can freely cross the nuclear envelope in hippocampal neurons: somatic calcium increases generate nuclear calcium transients

    Directory of Open Access Journals (Sweden)

    Bading Hilmar


    Full Text Available Abstract Background In hippocampal neurons, nuclear calcium signaling is important for learning- and neuronal survival-associated gene expression. However, it is unknown whether calcium signals generated by neuronal activity at the cell membrane and propagated to the soma can unrestrictedly cross the nuclear envelope to invade the nucleus. The nuclear envelope, which allows ion transit via the nuclear pore complex, may represent a barrier for calcium and has been suggested to insulate the nucleus from activity-induced cytoplasmic calcium transients in some cell types. Results Using laser-assisted uncaging of caged calcium compounds in defined sub-cellular domains, we show here that the nuclear compartment border does not represent a barrier for calcium signals in hippocampal neurons. Although passive diffusion of molecules between the cytosol and the nucleoplasm may be modulated through changes in conformational state of the nuclear pore complex, we found no evidence for a gating mechanism for calcium movement across the nuclear border. Conclusion Thus, the nuclear envelope does not spatially restrict calcium transients to the somatic cytosol but allows calcium signals to freely enter the cell nucleus to trigger genomic events.

  1. Calcium signals can freely cross the nuclear envelope in hippocampal neurons: somatic calcium increases generate nuclear calcium transients (United States)

    Eder, Anja; Bading, Hilmar


    Background In hippocampal neurons, nuclear calcium signaling is important for learning- and neuronal survival-associated gene expression. However, it is unknown whether calcium signals generated by neuronal activity at the cell membrane and propagated to the soma can unrestrictedly cross the nuclear envelope to invade the nucleus. The nuclear envelope, which allows ion transit via the nuclear pore complex, may represent a barrier for calcium and has been suggested to insulate the nucleus from activity-induced cytoplasmic calcium transients in some cell types. Results Using laser-assisted uncaging of caged calcium compounds in defined sub-cellular domains, we show here that the nuclear compartment border does not represent a barrier for calcium signals in hippocampal neurons. Although passive diffusion of molecules between the cytosol and the nucleoplasm may be modulated through changes in conformational state of the nuclear pore complex, we found no evidence for a gating mechanism for calcium movement across the nuclear border. Conclusion Thus, the nuclear envelope does not spatially restrict calcium transients to the somatic cytosol but allows calcium signals to freely enter the cell nucleus to trigger genomic events. PMID:17663775

  2. Induced calcium carbonate precipitation using Bacillus species. (United States)

    Seifan, Mostafa; Samani, Ali Khajeh; Berenjian, Aydin


    Microbially induced calcium carbonate precipitation is an emerging process for the production of self-healing concrete. This study was aimed to investigate the effects and optimum conditions on calcium carbonate biosynthesis. Bacillus licheniformis, Bacillus sphaericus, yeast extract, urea, calcium chloride and aeration were found to be the most significant factors affecting the biomineralization of calcium carbonate. It was noticed that the morphology of microbial calcium carbonate was mainly affected by the genera of bacteria (cell surface properties), the viscosity of the media and the type of electron acceptors (Ca2+). The maximum calcium carbonate concentration of 33.78 g/L was achieved at the optimum conditions This value is the highest concentration reported in the literature.

  3. Calcium excretion in feces of ungulates. (United States)

    Schryver, H F; Foose, T J; Williams, J; Hintz, H F


    1. Fecal excretion of calcium was examined in 122 individual ungulates representing 7 species of Equidae, 3 species of Tapiridae, 3 species of Rhinocerotidae, 2 species of Elephantidae, 2 species of Hippopotamidae, 12 species of Bovidae, 2 species of Cervidae, 3 species of Camellidae and 1 species of Giraffidae. 2. Animals were fed timothy hay, a low calcium diet or alfalfa hay, a high calcium diet. 3. In a few cases oat straw or prairie hay was used instead of timothy hay. 4. Samples of feces were obtained from individuals daily for 4 days following a 20 day dietary equilibration period. 5. Feces of equids, tapirs, rhinoceros and elephants had a lower calcium concentration and a lower Ca/P ratio than feces of ruminants when the animals were fed diets of equivalent calcium content. 6. The findings suggest that the non-ruminant ungulate equids, tapirs, rhinoceros and elephants absorb a larger proportion of dietary calcium than ruminants do.

  4. Binding of calcium and carbonate to polyacrylates. (United States)

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


    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.


    Directory of Open Access Journals (Sweden)

    N.I. Taibulatov


    Full Text Available The article is dedicated to the urgent issue of the pediatrics — calcium deficit among children. The authors provide modern data on the scheme of the normal calcium exchange in the human body. They also review the main diseases related to the disorders of the pho sphorocalcic metabolism, requiring prompt prevention and treatment by calcium based medications. The researchers stress the diseases of the musculoskeletal system, as insufficient calcium, phosphorus and vitamins supply of the child's body chiefly effects the state of the skeletal and muscular tissue. They give recommendations how to use the vitamin and mineral complex to correct calcium deficit.Key words: calcium deficit, diseases of the musculoskeletal system, vitamin and mineral complex, children.

  6. Altered calcium signaling in cancer cells. (United States)

    Stewart, Teneale A; Yapa, Kunsala T D S; Monteith, Gregory R


    It is the nature of the calcium signal, as determined by the coordinated activity of a suite of calcium channels, pumps, exchangers and binding proteins that ultimately guides a cell's fate. Deregulation of the calcium signal is often deleterious and has been linked to each of the 'cancer hallmarks'. Despite this, we do not yet have a full understanding of the remodeling of the calcium signal associated with cancer. Such an understanding could aid in guiding the development of therapies specifically targeting altered calcium signaling in cancer cells during tumorigenic progression. Findings from some of the studies that have assessed the remodeling of the calcium signal associated with tumorigenesis and/or processes important in invasion and metastasis are presented in this review. The potential of new methodologies is also discussed. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Coronary artery calcium scoring: Influence of adaptive statistical iterative reconstruction using 64-MDCT. (United States)

    Gebhard, Cathérine; Fiechter, Michael; Fuchs, Tobias A; Ghadri, Jelena R; Herzog, Bernhard A; Kuhn, Felix; Stehli, Julia; Müller, Ennio; Kazakauskaite, Egle; Gaemperli, Oliver; Kaufmann, Philipp A


    Assessment of coronary artery calcification is increasingly used for cardiovascular risk stratification. We evaluated the reliability of calcium-scoring results using a novel iterative reconstruction algorithm (ASIR) on a high-definition 64-slice CT scanner, as such data is lacking. In 50 consecutive patients Agatston scores, calcium mass and volume score were assessed. Comparisons were performed between groups using filtered back projection (FBP) and 20-100% ASIR algorithms. Calcium score was measured in the coronary arteries, signal and noise were measured in the aortic root and left ventricle. In comparison with FBP, use of 20%, 40%, 60%, 80%, and 100% ASIR resulted in reduced image noise between groups (7.7%, 18.8%, 27.9%, 39.86%, and 48.56%, respectively; pASIR algorithms Agatston coronary calcium scoring significantly decreased compared with FBP algorithms (837.3 ± 130.3; 802.2 ± 124.9, 771.5 ± 120.7; 744.7 ± 116.8, 724.5 ± 114.2, and 709.2 ± 112.3 for 0%, 20%, 40%, 60%, 80%, and 100% ASIR, respectively, pASIR results in image noise reduction. However, ASIR image reconstruction techniques for HDCT scans decrease Agatston coronary calcium scores. Thus, one needs to be aware of significant changes of the scoring results caused by different reconstruction methods. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  8. Calcium Treatment for FeSi-killed Fe-13 Pct Cr Stainless Steel with Various Top Slag Compositions (United States)

    Wang, Qi; Wang, Lijun; Zhai, Jun; Li, Jianmin; Chou, Kuochih


    Calcium treatment of Fe-13 pct Cr stainless steel, with inclusion modification as its main purpose, was evaluated on a laboratory scale. The stability diagram of Ca-Al was obtained using the FactSage software and could be divided into three parts based on the [Al] content: the ultra-low-Al region, the low-Al region, and the medium-high-Al region. Each of these regions required different amounts of calcium for inclusion modification. The ferrosilicon deoxidation product could be modified into low melting temperature inclusions by a CaO-SiO2 top slag in the ultra-low-Al region ([Al] content less than 40 ppm). Calcium treatment was necessary to modify the ferrosilicon deoxidation product into low melting temperature inclusions in the low-Al region ([Al] content from 40 to 100 ppm) for the CaO-SiO2-Al2O3 top slag. Calcium addition has a "liquid window" where adding calcium can accelerate inclusion modification. Adding calcium for 15 and 30 minutes resulted in complete modification times of 45 and 60 minutes, respectively, which indicates that early calcium treatment can produce plastic inclusions sooner. The relationship between the steel and inclusion content was determined by fitting the experimental data in the low-Al region. An appropriate range of T.Ca/T.O (total calcium content/total oxygen content) for inclusion modification is 0.99 to 1.44.

  9. Calcium dobesilate: pharmacology and future approaches. (United States)

    Tejerina, T; Ruiz, E


    1. Calcium dobesilate (2,5-dihydroxybenzene sulfonate) is a drug commonly used in the treatment of diabetic retinopathy and chronic venous insufficiency. 2. The pharmacology of calcium dobesilate reveals its ability to decrease capillary permeability, as well as platelet aggregation and blood viscosity. 3. Furthermore, recent data show that calcium dobesilate increases endothelium-dependent relaxation owing to an increase in nitric oxide synthesis.

  10. Presynaptic calcium dynamics of learning neurons


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


    We present a new model for the dynamics of the presynaptic intracellular calcium concentration in neurons evoked by various stimulation protocols. The aim of the model is twofold: We want to discuss the calcium transients during and after specific stimulation protocols as they are used to induce long-term-depression and long-term-potentiation. In addition we would like to provide a general tool which allows the comparison of different calcium experiments. This may help to draw conclusions on ...

  11. Protein-Mediated Precipitation of Calcium Carbonate


    Izabela Polowczyk; Anna Bastrzyk; Marta Fiedot


    Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. In addition, the turbidity of the reaction solution was acquire...

  12. A step towards cinacalcet testing for the diagnosis of primary hyperparathyroidism: comparison with the standardized intravenous calcium loading. A pilot study. (United States)

    Cailleux, A; Vuillermet, P; Basuyau, J P; Ménard, J F; Lefebvre, H; Kuhn, J M; Prévost, G


    A calcium load to suppress parathyroid hormone (PTH) secretion can help to perform the diagnosis in some case of primary hyperparathyroidism (PHPT) with atypical presentation. A similar test with calcimimetic, which avoids hypercalcaemia, would be of interest. Our proof of concept study was conducted to compare firstly the results of a single-dose cinacalcet testing with those of the standardized short-time calcium load in healthy control (HC) and secondly the results of the single-dose cinacalcet testing in HC and in PHPT. Twelve HCs received in a random order, at a 2-week interval, either 0·33 mmol/kg calcium gluconate intravenously for 3 h, or a single oral dose of 30 mg or 60 mg cinacalcet. Twelve PHPTs received 30 mg cinacalcet and twelve other PHPTs 60 mg cinacalcet orally. Calcaemia and serum PTH levels were measured basally and then hourly for 6 h. In HC, plasma calcium did not significantly change after cinacalcet intake, whereas calcaemia rose up to 3·47 ± 0·05 mmol/l (mean ± SEM) at the end of the calcium load. PTH dropped from basal level to a similar extend (≥80%) with 60 mg cinacalcet and calcium load, whereas the decrease was significantly lesser (P standardized calcium load test; PHPT patients have a lower response to 60 mg cinacalcet than HC. © 2015 John Wiley & Sons Ltd.

  13. Calcium and magnesium levels in isolated mitochondria from human cardiac biopsies. (United States)

    Saetersdal, T; Engedal, H; Røli, J; Myklebust, R


    A non-enzymatic method is presented for isolating mitochondria from small-sized human cardiac samples, including ventricular needle biopsies of 15-25 mg of wet weight. Electron microscopy demonstrates that these fractions are rich in structurally well preserved mitochondria. Calcium and magnesium levels of fractions are determined by atomic absorption flame spectroscopy. Comparative analyses are made in similar fractions of the mouse ventricle. Calcium concentrations of mitocondria isolated in the presence of ruthenium red do not differ significantly between the human auricle and ventricle, averaging 61 nmol Ca/mg protein and 68 nmol Ca/mg protein, respectively. Mitochondrial calcium level is lower in the mouse ventricular fractions, averaging 7 nmol Ca/mg protein. Mitochondrial magnesium amounts to slightly less than 60% of the calcium levels in the human heart, while it exceeds the calcium level by more than 100 per cent in the mouse heart. There is no significant difference of mitochondrial calcium between normal auricles, and, auricles of patients with increased right atrial mean pressure and/or volume overload.

  14. The high prevalence of pathologic calcium crystals in pre-operative knees. (United States)

    Derfus, Beth A; Kurian, Jason B; Butler, Jeffrey J; Daft, Laureen J; Carrera, Guillermo F; Ryan, Lawrence M; Rosenthal, Ann K


    Calcium pyrophosphate dihydrate (CPPD) and basic calcium phosphate (BCP) crystals are important in the pathogenesis of osteoarthritis (OA) but are under recognized even in end stage disease. We determined the prevalence of these calcium crystals in synovial fluid (SF) of persons undergoing total knee arthroplasty for degenerative arthritis. SF samples were obtained from 53 knee joints undergoing total arthroplasty for a pre-operative diagnosis of OA. SF were analyzed via compensated light microscopy for CPPD crystals and a semiquantitative radiometric assay for BCP crystals. Fifty pre-operative radiographs were analyzed and graded according to the scale of Kellgren and Lawrence. Patients had an average age of 70 years at the time of surgery. CPPD and/or BCP crystals were identified in 60% of SF. Overall radiographic scores correlated with mean concentrations of BCP crystals. Higher mean radiographic scores correlated with the presence of calcium-containing crystals of either type in SF Radiographic chondrocalcinosis was identified in only 31% of those with SF CPPD. Pathologic calcium crystals were present in a majority of SF at the time of total knee arthroplasty. Intraoperative SF analysis could conveniently identify pathologic calcium crystals providing information that may be relevant to the future care of the patient's replaced joint and that of other joints. This information could also potentially aid in predicting the likelihood of the need for contralateral total knee arthroplasty.

  15. Cardioprotection mechanism of mangiferin on doxorubicin-induced rats: Focus on intracellular calcium regulation. (United States)

    Agustini, Femmi Dwinda; Arozal, Wawaimuli; Louisa, Melva; Siswanto, Soni; Soetikno, Vivian; Nafrialdi, Nafrialdi; Suyatna, Franciscus


    The molecular mechanism of doxorubicin (DOX) cardiotoxicity involves overproduction of free radicals that leads to intracellular calcium dysregulation and apoptosis. Mangiferin (MGR), a naturally occurring glucosylxanthone, has antioxidant and cardioprotective properties. However, its cardioprotection mechanism has yet to be revealed. This study determines whether the cardioprotective effect of MGR is caused by its effect on intracellular calcium regulation. Male Sprague-Dawley rats were induced by DOX intraperitoneally with a total dose of 15 mg/kg bw. MGR was given orally at the doses of 30 and 60 mg/kg bw/d for seven consecutive weeks. The parameters examined were mRNA expression levels of proinflammatory cytokine gene (TNF-α), calcium regulatory gene (SERCA2a) and proapoptotic genes (caspase-9 and caspase-12), as well as cytosolic and mitochondrial calcium levels. Treatment with MGR at 60 mg/kg bw/d significantly decreased the mRNA expression levels of TNF-α by 44.55% and caspase-9 by 52.79%, as well as the cytosolic calcium level by 24.15% (p  0.05). Meanwhile, MGR 30 mg/kg bw/d gave insignificant results in all parameters. MGR protected against DOX-induced cardiac inflammation and apoptosis via down-regulation of proapoptotic and proinflammatory gene expressions, upregulation of SERCA2a gene expression, and normalization of cytosolic calcium level. Thus, the cardioprotective effect of MGR is at least in part due to the regulation of intracellular calcium homeostasis.

  16. Glutathione-Induced Calcium Shifts in Chick Retinal Glial Cells.

    Directory of Open Access Journals (Sweden)

    Hercules R Freitas

    Full Text Available Neuroglia interactions are essential for the nervous system and in the retina Müller cells interact with most of the neurons in a symbiotic manner. Glutathione (GSH is a low-molecular weight compound that undertakes major antioxidant roles in neurons and glia, however, whether this compound could act as a signaling molecule in neurons and/or glia is currently unknown. Here we used embryonic avian retina to obtain mixed retinal cells or purified Müller glia cells in culture to evaluate calcium shifts induced by GSH. A dose response curve (0.1-10 mM showed that 5-10 mM GSH, induced calcium shifts exclusively in glial cells (later labeled and identified as 2M6 positive cells, while neurons responded to 50 mM KCl (labeled as βIII tubulin positive cells. BBG 100 nM, a P2X7 blocker, inhibited the effects of GSH on Müller glia. However, addition of DNQX 70 μM and MK-801 20 μM, non-NMDA and NMDA blockers, had no effect on GSH calcium induced shift. Oxidized glutathione (GSSG at 5 mM failed to induce calcium mobilization in glia cells, indicating that the antioxidant and/or structural features of GSH are essential to promote elevations in cytoplasmic calcium levels. Indeed, a short GSH pulse (60s protects Müller glia from oxidative damage after 30 min of incubation with 0.1% H2O2. Finally, GSH induced GABA release from chick embryonic retina, mixed neuron-glia or from Müller cell cultures, which were inhibited by BBG or in the absence of sodium. GSH also induced propidium iodide uptake in Müller cells in culture in a P2X7 receptor dependent manner. Our data suggest that GSH, in addition to antioxidant effects, could act signaling calcium shifts at the millimolar range particularly in Müller glia, and could regulate the release of GABA, with additional protective effects on retinal neuron-glial circuit.

  17. Mechanical Properties of a Calcium Dietary Supplement, Calcium Fumarate Trihydrate. (United States)

    Sun, Shijing; Henke, Sebastian; Wharmby, Michael T; Yeung, Hamish H-M; Li, Wei; Cheetham, Anthony K


    The mechanical properties of calcium fumarate trihydrate, a 1D coordination polymer considered for use as a calcium source for food and beverage enrichment, have been determined via nanoindentation and high-pressure X-ray diffraction with single crystals. The nanoindentation studies reveal that the elastic modulus (16.7-33.4 GPa, depending on crystallographic orientation), hardness (1.05-1.36 GPa), yield stress (0.70-0.90 GPa), and creep behavior (0.8-5.8 nm/s) can be rationalized in view of the anisotropic crystal structure; factors include the directionality of the inorganic Ca-O-Ca chain and hydrogen bonding, as well as the orientation of the fumarate ligands. High-pressure single-crystal X-ray diffraction studies show a bulk modulus of ∼ 20 GPa, which is indicative of elastic recovery intermediate between small molecule drug crystals and inorganic pharmaceutical ingredients. The combined use of nanoindentation and high-pressure X-ray diffraction techniques provides a complementary experimental approach for probing the critical mechanical properties related to tableting of these dietary supplements.

  18. Calcium dependence of inactivation of calcium release from the sarcoplasmic reticulum in skeletal muscle fibers. (United States)

    Simon, B J; Klein, M G; Schneider, M F


    The steady-state calcium dependence of inactivation of calcium release from the sarcoplasmic reticulum was studied in voltage-clamped, cut segments of frog skeletal muscle fibers containing two calcium indicators, fura-2 and anti-pyrylazo III (AP III). Fura-2 fluorescence was used to monitor resting calcium and relatively small calcium transients during small depolarizations. AP III absorbance signals were used to monitor larger calcium transients during larger depolarizations. The rate of release (Rrel) of calcium from the sarcoplasmic reticulum was calculated from the calcium transients. The equilibrium calcium dependence of inactivation of calcium release was determined using 200-ms prepulses of various amplitudes to elevate [Ca2+] to various steady levels. Each prepulse was followed by a constant test pulse. The suppression of peak Rrel during the test pulse provided a measure of the extent of inactivation of release at the end of the prepulse. The [Ca2+] dependence of inactivation indicated that binding of more than one calcium ion was required to inactivate each release channel. Half-maximal inactivation was produced at a [Ca2+] of approximately 0.3 microM. Variation of the prepulse duration and amplitude showed that the suppression of peak release was consistent with calcium-dependent inactivation of calcium release but not with calcium depletion. The same calcium dependence of inactivation was obtained using different amplitude test pulses to determine the degree of inactivation. Prepulses that produced near maximal inactivation of release during the following test pulse produced no suppression of intramembrane charge movement during the test pulse, indicating that inactivation occurred at a step beyond the voltage sensor for calcium release. Three alternative set of properties that were assumed for the rapidly equilibrating calcium-binding sites intrinsic to the fibers gave somewhat different Rrel records, but gave very similar calcium dependence of

  19. Protein-Mediated Precipitation of Calcium Carbonate. (United States)

    Polowczyk, Izabela; Bastrzyk, Anna; Fiedot, Marta


    Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. In addition, the turbidity of the reaction solution was acquired to monitor the kinetics of the calcium carbonate structure's growth in the investigated system. In this study, samples of CaCO₃ particles obtained with individual proteins, such as ovalbumin, lysozyme, and a mixture of the proteins, were characterized and compared with a control sample, i.e., synthesized without proteins. The obtained data indicated that the addition of ovalbumin to the reaction changed the morphology of crystals from rhombohedral to 'stack-like' structures. Lysozyme, however, did not affect the morphology of calcium carbonate, yet the presence of the protein mixture led to the creation of more complex composites in which the calcium carbonate crystals were constructed in protein matrices formed by the ovalbumin-lysozyme interaction. It was also observed that in the protein mixture, ovalbumin has a major influence on the CaCO₃ formation through a strong interaction with calcium ions, which leads to the coalescence and creation of a steric barrier reducing particle growth. The authors proposed a mechanism of calcium carbonate grain growth in the presence of both proteins, taking into account the interaction of calcium ions with the protein.

  20. Diuretics and disorders of calcium homeostasis. (United States)

    Grieff, Marvin; Bushinsky, David A


    Diuretics commonly are administered in disorders of sodium balance. Loop diuretics inhibit the Na-K-2Cl transporter and also increase calcium excretion. They are often used in the treatment of hypercalcemia. Thiazide diuretics block the thiazide-sensitive NaCl transporter in the distal convoluted tubule, and can decrease calcium excretion. They are often used in the treatment of nephrolithiasis. Carbonic anhydrase inhibitors decrease bicarbonate absorption and the resultant metabolic acidosis can increase calcium excretion. Their use can promote nephrocalcinosis and nephrolithiasis. This review will address the use of diuretics on disorders of calcium homeostasis. Copyright © 2011 Elsevier Inc. All rights reserved.


    Polyakova, E P; Ksenofontov, D A; Revyakin, A O; Ivanov, A A


    Experiments on goats and rabbits showed that zinc supplement to the diet leads to calcium concentration rise in muscle, bone and blood of animals. However, this rise was not adequate to increase in.zinc consumption. The bulk of alimentary zinc stayed in soluble fraction, dense endogen fraction and infusoria fraction of digesta and stimulated calcium release from food particles, it's accumulation in digesta fractions and calcium utilization on the whole. Authors estimate animal digesta as homeostatic, spatial organized, endogenic formation in which zinc and calcium are functionally dependent through enteral mucosa.

  2. The Electronic Structure of Calcium

    DEFF Research Database (Denmark)

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


    .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......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...

  3. Short communication: Urinary oxalate and calcium excretion by dogs and cats diagnosed with calcium oxalate urolithiasis

    NARCIS (Netherlands)

    Dijcker, J.C.; Kummeling, A.; Hagen-Plantinga, E.A.; Hendriks, W.H.


    Introduction Urine concentrations of oxalate and calcium play an important role in calcium oxalate (CaOx) urolith formation in dogs and cats, with high excretions of both substances increasing the chance of CaOx urolithiasis. In 17 CaOx-forming dogs, urine calcium:creatinine ratio (Ca:Cr) was found

  4. Impaired body calcium metabolism with low bone density and compensatory colonic calcium absorption in cecectomized rats

    NARCIS (Netherlands)

    Jongwattanapisan, P.; Suntornsaratoon, P.; Wongdee, K.; Dorkkam, N.; Krishnamra, N.; Charoenphandhu, N.


    An earlier study reported that cecal calcium absorption contributes less than 10% of total calcium absorbed by the intestine, although the cecum has the highest calcium transport rate compared with other intestinal segments. Thus, the physiological significance of the cecum pertaining to body

  5. AII amacrine cells express L-type calcium channels at their output synapses. (United States)

    Habermann, Christopher J; O'Brien, Brendan J; Wässle, Heinz; Protti, Dario A


    AII amacrine cells play a critical role in the high-fidelity signal transmission pathways involved with nighttime vision. The temporal properties of the light responses strongly depend on the transfer function at different synaptic stages and consequently on presynaptic calcium influx. AII light responses are complex waveforms generated by graded input, they comprise Na+-based spikes as well as a sustained component, and they are transferred to graded cone bipolar cells. It is, therefore, of interest to determine the properties of AII voltage-dependent calcium channels (VDCCs) to establish whether these cells express N-type and/or P/Q-type VDCCs, characteristic of spiking neurons, or whether they are more like graded neurons, which mostly use L-type VDCCs. We combined electrophysiological, molecular biological, and imaging techniques to characterize calcium currents and their sites of origin in mouse AII amacrine cells. Calcium currents activated at potentials more positive than -60 mV (maximally between -50 and -20 mV) and inactivated slowly. These currents were blocked by dihydropyridine (DHP) antagonists and were enhanced by the DHP agonist BayK 8644. Single-cell RT-PCR analysis of mRNA encoding for different calcium channel alpha subunits in AIIs revealed a consistent expression of the alpha1-D subunit. Calcium imaging of AII cells showed that the greatest change in intracellular calcium occurred in the lobular appendages, with minor changes being observed in the arboreal dendrites. Depolarization-induced calcium rises were also modulated by DHPs, suggesting that a particular kind of L-type VDCC, mainly localized to the lobular appendages, enables these spiking-capable neurons to release neurotransmitter in a sustained manner onto OFF-cone bipolar cells.

  6. Plasma membrane calcium pump and sodium-calcium exchanger in maintenance and control of calcium concentrations in platelets. (United States)

    Juska, Alfonsas


    The purpose of this research was to elucidate the activity of the mechanisms responsible for control of cytosolic calcium concentration in platelets by modeling the time-course of the concentration changing in response to discharge of the intracellular stores or store-operated calcium entry (SOCE). The parameters estimated as a result of model fitting to experimental data are related to physiological or pathological state of the cells. It has been shown that: (a) the time-course is determined by the passive calcium fluxes and activities of the corresponding mechanisms; (b) the decline in the concentration (after its rise) develops due to activity of plasma membrane calcium ATPase (PMCA) both in the case of discharge of the stores of platelets contained in calcium-free medium and in the case of SOCE; (c) impulsive extrusion of calcium in response to its sudden influx, presumably, is the main function of PMCA; (d) the function of sodium-calcium exchanger (NCX) is to extrude calcium excess by permanent counteracting its influx. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  7. The preparation of calcium superoxide at subambient temperatures and pressures. [oxygen source for breathing apparatus (United States)

    Ballou, E. V.; Wood, P. C.; Spitze, L. A.; Wydeven, T.; Stein, R.


    The effects of disproportionations at lower temperatures and also of a range of reaction chamber pressures on the preparation of calcium superoxide, Ca(O2)2, from calcium peroxide diperoxyhydrate were studied. About 60% purity of product was obtained by a disproportionation procedure. The significance of features of this procedure for a prospective scale-up of the mass prepared in a single experiment is considered. The optimum pressure for product purity was determined, and the use of a molecular sieve desiccant is described.

  8. Repassivation Potential of Alloy 22 in Sodium and Calcium Chloride Brines

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Ilevbare, G O; Carranza, R M


    A comprehensive matrix of 60 tests was designed to explore the effect of calcium chloride vs. sodium chloride and the ratio R of nitrate concentration over chloride concentration on the repassivation potential of Alloy 22. Tests were conducted using the cyclic potentiodynamic polarization (CPP) technique at 75 C and at 90 C. Results show that at a ratio R of 0.18 and higher nitrate was able to inhibit the crevice corrosion in Alloy 22 induced by chloride. Current results fail to show in a consistent way a different effect on the repassivation potential of Alloy 22 for calcium chloride solutions than for sodium chloride solutions.

  9. Child Passenger Safety PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement, based on the February 2014 Vital Signs release, discusses the importance of buckling up to reduce injuries and save lives.  Created: 2/4/2014 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 2/4/2014.

  10. NA60 frees the quarks

    CERN Multimedia


    Fitted with new state-of-the-art silicon detectors, NA60 is prepared to study the phase transition from confined hadronic matter to a deconfined (free) quark-gluon plasma, a state of matter which probably existed an instant after the Big Bang.

  11. PSA (:60) Moho/ Hongos (Mold)

    Centers for Disease Control (CDC) Podcasts


    Este anuncio de servicio público de 60 segundos habla sobre la importancia de eliminar el moho (hongos) después de una emergencia.  Created: 10/25/2017 by Centers for Disease Control and Prevention (CDC).   Date Released: 10/25/2017.

  12. Preventing Stroke Deaths PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the July 2017 CDC Vital Signs report. Higher opioid prescribing puts patients at risk for addiction and overdose. Learn what can be done about this serious problem.  Created: 9/6/2017 by Centers for Disease Control and Prevention (CDC).   Date Released: 9/6/2017.

  13. Raccoon Roundworm Infection PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second PSA describes the signs and symptoms of and ways to prevent Baylisascaris infection, a parasitic roundworm infection that is spread through raccoon feces.  Created: 8/27/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 8/28/2012.

  14. Pseudogout and Calcium Pyrophosphate Disease

    Directory of Open Access Journals (Sweden)

    Andrew Williamson


    Full Text Available History of present illness: A 53-year-old male presented with worsening right knee pain and swelling over the past 48 hours. He denied recent trauma to the knee, history of IV drug use, and recent illness. He had no history of diabetes, immunodeficiency, chronic steroids, rheumatologic disease, or knee replacement. He described the pain as sharp, non-radiating, and worse with movement. He was unable to walk due to pain. Significant findings: Radiographs of the knee showed multiple radio-dense lines paralleling the articular surface (see red arrows consistent with calcium pyrophosphate crystal deposition within the joint often seen in calcium pyrophosphate disease (CPPD also known as pseudogout. Discussion: Patients commonly present to the emergency department with non-traumatic joint pain. Arthrocentesis is an important diagnostic tool to evaluate for septic arthritis, gout, or pseudogout. Arthrocentesis can demonstrate crystals or abnormal cell count, gram stain, and culture.[1] In the evaluation of joint pain, plain films are usually obtained to evaluate for fracture, dislocation, effusion, or secondary signs of infection. In this case the classic x-ray supported the diagnosis of CPPD.2 The patient was found to have positively birefringent rhomboid shaped crystals consistent with pseudogout on arthrocentesis. Gram stain and culture were both negative. The patient was discharged with NSAIDs and had significant improvement in symptoms upon follow up with primary care physician in 3 days.

  15. Paclitaxel induces apoptosis in breast cancer cells through different calcium--regulating mechanisms depending on external calcium conditions. (United States)

    Pan, Zhi; Avila, Andrew; Gollahon, Lauren


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

  16. Spatiotemporal intracellular calcium dynamics during cardiac alternans (United States)

    Restrepo, Juan G.; Karma, Alain


    Cellular calcium transient alternans are beat-to-beat alternations in the peak cytosolic calcium concentration exhibited by cardiac cells during rapid electrical stimulation or under pathological conditions. Calcium transient alternans promote action potential duration alternans, which have been linked to the onset of life-threatening ventricular arrhythmias. Here we use a recently developed physiologically detailed mathematical model of ventricular myocytes to investigate both stochastic and deterministic aspects of intracellular calcium dynamics during alternans. The model combines a spatially distributed description of intracellular calcium cycling, where a large number of calcium release units are spatially distributed throughout the cell, with a full set of ionic membrane currents. The results demonstrate that ion channel stochasticity at the level of single calcium release units can influence the whole-cell alternans dynamics by causing phase reversals over many beats during fixed frequency pacing close to the alternans bifurcation. They also demonstrate the existence of a wide range of dynamical states. Depending on the sign and magnitude of calcium-voltage coupling, calcium alternans can be spatially synchronized or desynchronized, in or out of phase with action potential duration alternans, and the node separating out-of-phase regions of calcium alternans can be expelled from or trapped inside the cell. This range of states is found to be larger than previously anticipated by including a robust global attractor where calcium alternans can be spatially synchronized but out of phase with action potential duration alternans. The results are explained by a combined theoretical analysis of alternans stability and node motion using general iterative maps of the beat-to-beat dynamics and amplitude equations.

  17. Calcium Blood Test: MedlinePlus Lab Test Information (United States)

    ... this page: Calcium Blood Test To use the sharing features on this page, please enable JavaScript. What is a Calcium Blood Test? A calcium blood test measures the ...

  18. Rates of calcium carbonate removal from soils.

    NARCIS (Netherlands)

    Breemen, van N.; Protz, R.


    Mean annual rates of calcium carbonate removal from soils in a subarctic climate estimated from data on two chronosequences of calcareous storm ridges, appeared to be relatively constant through time. Concentrations of dissolved calcium carbonate in the soil solution in the study sites calculated

  19. Calcium and M'yocardial Infarction

    African Journals Online (AJOL)


    Mar 16, 1974 ... Urinary excretion of calcium tended to be even lower in these .... 16 March 1974. S.A. MEDICAL JOURNAL. 525. 150. 50. Fig. 5. Urine calcium in myocardial infarction (means and standard error relative to age). AGE OF PATIENT .... Plasma proteins and blood urea were also measured in. 10 consecutive ...

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

    Directory of Open Access Journals (Sweden)

    R. Mänd


    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.

  1. 21 CFR 182.8223 - Calcium pyrophosphate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pyrophosphate. 182.8223 Section 182.8223 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8223 Calcium...

  2. 21 CFR 182.8217 - Calcium phosphate. (United States)


    ... 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 HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8217 Calcium...

  3. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald


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

  4. Role of calcium in selenium cataract. (United States)

    Shearer, T R; David, L L

    The purpose of this research was to test the role of certain minerals in the formation of cataract caused by an overdose of selenium. Several pieces of information indicated that lenticular calcium may play an important role in selenite cataractogenesis: 1) Lens calcium concentrations in selenite treated rats were increased more than 5-fold, and the increase in lens calcium was localized in the nucleus. 2) Lens calcium concentrations were elevated at least one full day before actual formation of nuclear cataract, but serum calcium levels were not changed. 3) In older rats not susceptible to selenite cataract, lens calcium was not significantly increased. 4) No evidence was found for a generalized disruption in lens permeability, since no major changes in lens water, sodium, and potassium levels were observed, and 5) when levels of calcium observed in selenite cataract were added to solutions of soluble proteins from rat lenses, light scattering was increased. Selenium-overdose cataracts may provide an important model for studies on the role of calcium in cataractogenesis.

  5. Adding calcium improves lithium ferrite core (United States)

    Lessoff, H.


    Adding calcium increases uniformity of grain growth over a wide range of sintering temperatures and reduces porosity within the grain. Ferrite cores containing calcium have square hysteresis loops and high curie temperatures, making them useful in coincident current memories of digital electronic computers.

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

    DEFF Research Database (Denmark)

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


    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...

  7. Comparison of Serum Calcium and Magnesium Between ...

    African Journals Online (AJOL)

    The present study compared serum calcium and magnesium in forty preeclamptic (cases) and forty normotensive (control) pregnant women matched for age, parity, and socioeconomic status. Serum calcium and magnesium levels were measured using atomic absorption spectrophotometer. Statistical analysis was done ...

  8. Dairy Dilemma: Are You Getting Enough Calcium? (United States)

    ... body also needs vitamin D to absorb calcium. Nutrition surveys have shown that most people in the U.S. aren’t getting the calcium they need. If you’re avoiding milk and dairy ... taking nutritional supplements and choosing reduced-lactose or non-dairy ...


    NARCIS (Netherlands)



    Diet is a major determinant of colon cancer risk. Calcium may protect against colon cancer, presumably by binding cytotoxic bile acids and fatty acids. Numerous studies support this proposition. In subjects at risk for colon cancer oral calcium supplementation has been shown to reduce rectal

  10. Bespuiten met calcium kan neusrot voorkomen

    NARCIS (Netherlands)

    Blom-Zandstra, Greet; Marcelis, L.F.M.


    Oorzaak van neusrot bij paprika is een calciumtekort in de vrucht. Een bespuiting met calcium vlak na de bloei heeft een zeer gunstig effect. In bijgaande tabel gegevens over het effect van spuiten met calcium op het optreden van neusrot bij paprika

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

    Directory of Open Access Journals (Sweden)

    C.J. Van Dijk


    Full Text Available The effects of anionic salts in the transition diet on serum and urine calcium at calving and on peripartal health, subsequent milk production and fertility performance were studied in a well-managed, high-producing Friesland dairy herd. Over a period of a year, approximately 21 days before the expected date of calving, 28 pre-partum heifers and 44 multiparous dry cows were randomly allocated within parity to 1 of 2 transition diets, designated control and experimental anionic diets. The anionic diet contained the same quantities of the basic transition ration fed to the control group as well as a standard anionic salt mixture containing 118 g NH4Cl, 36 g (NH42SO4 and 68 g MgSO4 (total 222 g per animal per day. This reduced the DCAD to -11.68 mEq/100 g dietary dry matter compared to +13.57 for the control diet. Blood and urine were randomly sampled from 7 to 8 animals within each category within 3 hours post-partum. Serum calcium (total and ionised and creatinine, urine calcium and creatinine and the fractional clearance of calcium were assessed. Relevant clinical, milk production, and fertility data were collected. The total serum calcium (2.07 versus 1.60 mmol/ , serum ionised calcium (1.12 vs 1.02 mmol/ , urine calcium (0.92 vs 0.10 mmol/ and the fractional clearance of calcium (1.88 vs 0.09 % were significantly higher (P <0.01 at calving for multiparous cows fed the anionic diet compared to those fed the control diet. In the primiparous cows there were no significant differences in serumcalcium levels. However, the urine calcium (1.07 vs 0.43 mmol/ and the fractional clearance of calcium was higher (1.75 vs 0.45 % in cows fed the anionic diet (P <0.05 and 0.01 respectively. These results illustrated that there were benefits, although no differences were demonstrated with respect to health, milk production or fertility. The supplementation of diets with anionic salts in the last 2-3 weeks before calving has the potential to significantly

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

    Directory of Open Access Journals (Sweden)

    Sandra Tavares da Silva


    Full Text Available 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 at a temperature of 24°±2ºC, light/dark cycles of 12/12 hours, and deionized water available ad libitum. On the 8th week of the experiment, food consumption was measured and 24-hour urine and 4-day feces were collected to determine calcium balance [Balance=Ca intake-(Urinary Ca+Fecal Ca]. RESULTS: Animals with adequate calcium intake presented higher balances and rates of calcium absorption and retention (p<0.05 than those with inadequate calcium intake, regardless of caffeine intake (p<0.05. Caffeine intake did not affect urinary calcium excretion but increased balance (p<0.05 in the groups with adequate calcium intake. CONCLUSION: Adequate calcium intake attenuated the negative effects of estrogen deficiency and improved calcium balance even in the presence of caffeine.

  13. Store-operated calcium entry is essential for glial calcium signalling in CNS white matter. (United States)

    Papanikolaou, M; Lewis, A; Butt, A M


    'Calcium signalling' is the ubiquitous response of glial cells to multiple extracellular stimuli. The primary mechanism of glial calcium signalling is by release of calcium from intracellular stores of the endoplasmic reticulum (ER). Replenishment of ER Ca(2+) stores relies on store-operated calcium entry (SOCE). However, despite the importance of calcium signalling in glial cells, little is known about their mechanisms of SOCE. Here, we investigated SOCE in glia of the mouse optic nerve, a typical CNS white matter tract that comprises bundles of myelinated axons and the oligodendrocytes and astrocytes that support them. Using quantitative RT-PCR, we identified Orai1 channels, both Stim1 and Stim2, and the transient receptor potential M3 channel (TRPM3) as the primary channels for SOCE in the optic nerve, and their expression in both astrocytes and oligodendrocytes was demonstrated by immunolabelling of optic nerve sections and cultures. The functional importance of SOCE was demonstrated by fluo-4 calcium imaging on isolated intact optic nerves and optic nerve cultures. Removal of extracellular calcium ([Ca(2+)]o) resulted in a marked depletion of glial cytosolic calcium ([Ca(2+)]i), which recovered rapidly on restoration of [Ca(2+)]o via SOCE. 2-aminoethoxydiphenylborane (2APB) significantly decreased SOCE and severely attenuated ATP-mediated calcium signalling. The results provide evidence that Orai/Stim and TRPM3 are important components of the 'calcium toolkit' that underpins SOCE and the sustainability of calcium signalling in white matter glia.

  14. Plant Calcium Content: Ready to Remodel

    Directory of Open Access Journals (Sweden)

    Mary Lou Guerinot


    Full Text Available By identifying the relationship between calcium location in the plant cell and nutrient bioavailability, the plant characteristics leading to maximal calcium absorption by humans can be identified. Knowledge of plant cellular and molecular targets controlling calcium location in plants is emerging. These insights should allow for better strategies for increasing the nutritional content of foods. In particular, the use of preparation-free elemental imaging technologies such as synchrotron X-ray fluorescence (SXRF microscopy in plant biology may allow researchers to understand the relationship between subcellular location and nutrient bioavailability. These approaches may lead to better strategies for altering the location of calcium within the plant to maximize its absorption from fruits and vegetables. These modified foods could be part of a diet for children and adults identified as at-risk for low calcium intake or absorption with the ultimate goal of decreasing the incidence and severity of inadequate bone mineralization.

  15. Endoplasmic reticulum calcium stores in dendritic spines. (United States)

    Segal, Menahem; Korkotian, Eduard


    Despite decades of research, the role of calcium stores in dendritic spines structure, function and plasticity is still debated. The reasons for this may have to do with the multitude of overlapping calcium handling machineries in the neuron, including stores, voltage and ligand gated channels, pumps and transporters. Also, different cells in the brain are endowed with calcium stores that are activated by different receptor types, and their differential compartmentalization in dendrites, spines and presynaptic terminals complicates their analysis. In the present review we address several key issues, including the role of calcium stores in synaptic plasticity, their role during development, in stress and in neurodegenerative diseases. Apparently, there is increasing evidence for a crucial role of calcium stores, especially of the ryanodine species, in synaptic plasticity and neuronal survival.

  16. Application of Calcium Phosphate Materials in Dentistry

    Directory of Open Access Journals (Sweden)

    Jabr S. Al-Sanabani


    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.

  17. Calcium phosphate: a substitute for aluminum adjuvants? (United States)

    Masson, Jean-Daniel; Thibaudon, Michel; Bélec, Laurent; Crépeaux, Guillemette


    Calcium phosphate was used as an adjuvant in France in diphtheria, tetanus, pertussis and poliomyelitis vaccines. It was later completely substituted by alum salts in the late 80's, but it still remains as an approved adjuvant for the World Health Organization for human vaccination. Area covered: Thus, calcium phosphate is now considered as one of the substances that could replace alum salts in vaccines. The aim of this paper is to draw a review of existing data on calcium phosphate as an adjuvant in order to bring out the strengths and weaknesses for its use on a large scale. Expert commentary: Calcium phosphate is a compound naturally present in the organism, safe and already used in human vaccination. Beyond comparisons with the other adjuvants, calcium phosphate represents a good candidate to replace or to complete alum salts as a vaccine adjuvant.

  18. Plant Calcium Content: Ready to Remodel (United States)

    Yang, Jian; Punshon, Tracy; Guerinot, Mary Lou; Hirschi, Kendal D.


    By identifying the relationship between calcium location in the plant cell and nutrient bioavailability, the plant characteristics leading to maximal calcium absorption by humans can be identified. Knowledge of plant cellular and molecular targets controlling calcium location in plants is emerging. These insights should allow for better strategies for increasing the nutritional content of foods. In particular, the use of preparation-free elemental imaging technologies such as synchrotron X-ray fluorescence (SXRF) microscopy in plant biology may allow researchers to understand the relationship between subcellular location and nutrient bioavailability. These approaches may lead to better strategies for altering the location of calcium within the plant to maximize its absorption from fruits and vegetables. These modified foods could be part of a diet for children and adults identified as at-risk for low calcium intake or absorption with the ultimate goal of decreasing the incidence and severity of inadequate bone mineralization. PMID:23016135

  19. The calcium and vitamin D controversy

    DEFF Research Database (Denmark)

    Abrahamsen, Bo


    or subanalyses while maintaining balancing. Though large clinical RCTs currently evaluate the effects of higher vitamin D doses (equivalent to 50–83 μg/d) there is no current research effort regarding the calcium controversy. In the absence of such studies it is not possible to provide clinicians with evidence......Areas of the world where vitamin D levels are low for months of the year and intakes of calcium are high have a high prevalence of osteoporosis and cardiovascular disease. This suggests a public health message of avoiding calcium supplements and increasing vitamin D intake. No message could be more...... welcome as vitamin D can be given as a bolus while calcium must be taken daily and may be poorly tolerated. This approach is based on no evidence from intervention studies. Randomized controlled trials (RCTs) suggest that vitamin D given with calcium elicits a small reduction in fracture risk and deaths...

  20. Expert review on coronary calcium

    Directory of Open Access Journals (Sweden)

    Matthew J Budoff


    Full Text Available Matthew J Budoff, Khawar M GulDivision of Cardiology, Saint John’s Cardiovascular Research Center, Los Angeles Biomedical Research Institute at Harbor-UCLA, Torrance, California, USAAbstract: While there is no doubt that high risk patients (those with >20% ten year risk of future cardiovascular event need more aggressive preventive therapy, a majority of cardiovascular events occur in individuals at intermediate risk (10%–20% ten year risk. Accurate risk assessment may be helpful in decreasing cardiovascular events through more appropriate targeting of preventive measures. It has been suggested that traditional risk assessment may be refined with the selective use of coronary artery calcium (CAC or other methods of subclinical atherosclerosis measurement. Coronary calcification is a marker of atherosclerosis that can be quantified with the use of cardiac CT and it is proportional to the extent and severity of atherosclerotic disease. The published studies demonstrate a high sensitivity of CAC for the presence of coronary artery disease but a lower specificity for obstructive CAD depending on the magnitude of the CAC. Several large clinical trials found clear, incremental predictive value of CAC over the Framingham risk score when used in asymptomatic patients. Based on multiple observational studies, patients with increased plaque burdens (increased CAC are approximately ten times more likely to suffer a cardiac event over the next 3–5 years. Coronary calcium scores have outperformed conventional risk factors, highly sensitive C-reactive protein (CRP and carotid intima media thickness (IMT as a predictor of cardiovascular events. The relevant prognostic information obtained may be useful to initiate or intensify appropriate treatment strategies to slow the progression of atherosclerotic vascular disease. Current data suggests intermediate risk patients may benefit most from further risk stratification with cardiac CT, as CAC testing is

  1. Biocompatibility of a new nanomaterial based on calcium silicate implanted in subcutaneous connective tissue of rats

    Directory of Open Access Journals (Sweden)

    Petrović Violeta


    Full Text Available The aim of the study was to investigate rat connective tissue response to a new calcium silicate system 7, 15, 30 and 60 days after implantation. Twenty Wistar albino male rats received two tubes half-filled with a new calcium silicate system (NCSS or MTA in subcutaneous tissue. The empty half of the tubes served as controls. Five animals were sacrificed after 7, 15, 30 and 60 days and samples of the subcutaneous tissue around implanted material were submitted to histological analysis. The intensity of inflammation was evaluated based on the number of inflammatory cells present. Statistical analysis was performed using one way ANOVA and Holm Sidak's multiple comparison tests. Mild to moderate inflammatory reaction was observed after 7, 15 and 30 days around a NCSS while mild inflammatory reaction was detected after 60 days of implantation. In the MTA group, mild to moderate inflammatory reaction was found after 7 and 15 days while mild inflammatory reaction was present after 30 and 60 days. There was no statistically significant difference in the intensity of inflammatory reactions between the tested materials and control groups in any experimental period (ANOVA p>0.05. Regarding the intensity of inflammatory reactions at different experimental periods, a statistically significant difference was observed between 7 and 30 days, 7 and 60 days and 15 to 60 days for both materials. For the controls, a statistically significant difference was found between 7 and 60 days and 15 and 60 days of the experiment (Holm Sidak < p 0.001. Subcutaneous tissue of rats showed good tolerance to a new calcium silicate system. Inflammatory reaction was similar to that caused by MTA. [Projekat Ministarstva nauke Republike Srbije, br. 172026

  2. Positronium formation from C60 (United States)

    Hervieux, Paul-Antoine; Chakraborty, Anzumaan; Chakraborty, Himadri


    Due to the dominant electron capture by positrons from the molecular shell and the spatial dephasing across the shell-width, a powerful diffraction effect universally underlies the positronium (Ps) formation from C60. This results into trains of resonances in the Ps formation cross section as a function of the positron beam energy, producing structures in recoil momenta in analogy with classical single-slit diffraction fringes in the configuration space. C60 is modeled by a jellium-based local-density approximation (LDA) method and the Ps formation is treated by the continuum distorted-wave final-state (CDW-FS) approximation. The work may motivate application of the Ps formation spectroscopy to gas-phase nanoparticles and also the access target-level- as well as Ps-level-differential measurements. This work was supported by the U.S. National Science Foundation.

  3. Arthritis in America PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the March 2017 CDC Vital Signs report. Many adults in the United States have arthritis. Learn how to reduce the pain of arthritis, as well as manage the condition.  Created: 3/7/2017 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 3/7/2017.

  4. Preventing Norovirus Outbreaks PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the June 2014 CDC Vital Signs report. Norovirus infects about 20 million Americans each year. Learn how to protect yourself and your family from this very contagious, potentially serious illness.  Created: 6/3/2014 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 6/3/2014.

  5. Cancer and Obesity PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the October 2017 CDC Vital Signs report. Obesity is a leading cancer risk factor. Unfortunately, two out of three U.S. adults weigh more than recommended. Find out what can be done to help people get to and keep a healthy weight.  Created: 10/4/2017 by Centers for Disease Control and Prevention (CDC).   Date Released: 10/4/2017.

  6. Preventing Teen Pregnancy PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the April 2015 CDC Vital Signs report. Teen births in the U.S. have declined, but still, more than 273,000 infants were born to teens ages 15 to 19 in 2013. Learn about the most effective types of birth control.  Created: 4/7/2015 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 4/7/2015.

  7. Torleif Ericson 60th Birthday

    CERN Multimedia



    Plusieurs discours à l'occasion du 60me anniversaire de Torleif Ericson, physicien né à Lund (Suède), et remerciements pour son travail et son effort de relier la physique des particules à la physique nucléaire. A la fin de la cérémonie un document scientifique de 400 pages "die Festschrift" lui est remis comme cadeau d'anniversaire avec un grand nombre de contributions d'amis etc...

  8. Alcohol Poisoning Deaths PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second Public Service Announcement is based on the January 2015 CDC Vital Signs report. In the United States, an average of six people die every day from alcohol poisoning. Learn what you can do to prevent binge drinking and alcohol poisoning.  Created: 1/6/2015 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 1/6/2015.

  9. African American Health PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the May 2017 CDC Vital Signs report. The life expectancy of African Americans has improved, but it’s still an average of four years less than whites. Learn what can be done so all Americans can have the opportunity to pursue a healthy lifestyle.  Created: 5/2/2017 by Centers for Disease Control and Prevention (CDC).   Date Released: 5/2/2017.

  10. Prescription Painkiller Overdoses PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second public service announcement is based on the July 2013 CDC Vital Signs report. Prescription painkiller overdoses are an under-recognized and growing problem among women. This program includes things that women and health care providers can do to reduce the risk of overdose.  Created: 7/2/2013 by Centers for Disease Control and Prevention (CDC).   Date Released: 7/2/2013.

  11. Serum Ionized Calcium May Be Related to White Matter Lesion Volumes in Older Adults: A Pilot Study

    Directory of Open Access Journals (Sweden)

    John J. B. Anderson


    Full Text Available White matter lesions have detrimental effects upon older adults, while serum calcium levels have been associated with elevated vascular risk and may be associated with these lesions. Depression, a serious mental disorder characterized by disturbances in calcium metabolism, may be an important contributor to any calcium-lesion relationship. This cross-sectional pilot study examined the association between serum ionized calcium (the physiologically active form of calcium and white matter lesion volumes in a sample of depressed and non-depressed older adults (N = 42; 60 years and older. Serum ionized calcium was determined using an ion-selective electrode technique, while lesion volumes were estimated from magnetic resonance imaging using an automated expectation-maximization segmentation. A linear regression model, controlling for age and group (depression vs. comparison, showed a trend for a positive relationship between serum ionized calcium and white matter lesion volume (β = 4.34, SE = 2.27, t = 1.91, p = 0.063. Subsample analyses with depressed participants showed a significant positive relationship between higher ionic calcium and greater lesion volume (β = 6.41, SE = 2.53, t = 2.53, p = 0.018, but no association was found for non-depressed participants. Sex-specific subsample analyses showed a significant positive relationship between higher calcium and greater lesion volume in men only (β = 7.49, SE = 3.42, t = 2.19, p = 0.041. These preliminary results indicate that serum ionized calcium may be associated with white matter lesions in older adults, particularly among men and individuals with depression. Larger studies are needed to confirm these findings.

  12. Strontium Substitution for Calcium in Lithogenesis (United States)

    Blaschko, Sarah D.; Chi, Thomas; Miller, Joe; Flechner, Lawrence; Fakra, Sirine; Kapahi, Pankaj; Kahn, Arnold; Stoller, Marshall L.


    Purpose Strontium has chemical similarity to calcium, which enables the replacement of calcium by strontium in biomineralization processes. Incorporating strontium into human bone and teeth has been studied extensively but little research has been performed of the incorporation of strontium into urinary calculi. We used synchrotron based x-ray fluorescence and x-ray absorption techniques to examine the presence of strontium in different types of human kidney stones. Materials and Methods Multiple unique human stone samples were obtained via consecutive percutaneous nephrolithotomies/ureteroscopies. A portion of each stone was sent for standard laboratory analysis and a portion was retained for x-ray fluorescence and x-ray absorption measurements. X-ray fluorescence and x-ray absorption measurements determined the presence, spatial distribution and speciation of strontium in each stone sample. Results Traditional kidney stone analyses identified calcium oxalate, calcium phosphate, uric acid and cystine stones. X-ray fluorescence measurements identified strontium in all stone types except pure cystine. X-ray fluorescence elemental mapping of the samples revealed co-localization of calcium and strontium. X-ray absorption measurements of the calcium phosphate stone showed strontium predominately present as strontium apatite. Conclusions Advanced x-ray fluorescence imaging identified strontium in all calcium based stones, present as strontium apatite. This finding may be critical since apatite is thought to be the initial nidus for calcium stone formation. Strontium is not identified by standard laboratory stone analyses. Its substitution for calcium can be reliably identified in stones from multiple calcium based stone formers, which may offer opportunities to gain insight into early events in lithogenesis. PMID:23260568

  13. A comparison of total calcium, corrected calcium, and ionized calcium concentrations as indicators of calcium homeostasis among hypoalbuminemic dogs requiring intensive care. (United States)

    Sharp, Claire R; Kerl, Marie E; Mann, F A


    (1) To evaluate whether total calcium (tCa) correlates with ionized calcium (iCa) in hypoalbuminemic dogs; (2) to evaluate whether calcium adjusted for albumin (Alb), or total protein (TP), or both accurately predict iCa concentrations and hence can be used to monitor calcium homeostasis in critically ill hypoalbuminemic dogs; and (3) to evaluate factors associated with any potential discrepancy in calcium classification between corrected total and ionized values. Prospective observational clinical study. Small animal intensive care unit in a veterinary medical teaching hospital. Twenty-eight client-owned dogs with hypoalbuminemia. None. iCa was determined using ion-specific electrode methodology, on heparinized plasma. The tCa concentration was adjusted for Alb and TP using published equations. In total 29% (8/28) of the hypoalbuminemic, critically ill dogs in this study were hypocalcemic at intensive care unit admission, as determined by iCa measurement. Corrected calcium values failed to accurately classify calcium status in 67.9% and 64.3% of cases, according to whether the Alb-adjusted or TP-adjusted values, respectively, were used. The sensitivity and specificity of the tCa to evaluate hypocalcemia was 100% and 47%, respectively. The sensitivity and specificity of the correction formulae were 37.5% and 79% for the Alb-adjusted values and 37.5% and 74% for TP-adjusted values. tCa overestimated the presence of hypocalcemia and underestimated the presence of normocalcemia, while corrected calcium values overestimated the presence of normocalcemia and underestimated the presence of hypocalcemia. Calcium homeostasis in hypoalbuminemic critically ill dogs should be evaluated by iCa concentrations rather than tCa or calcium adjusted for Alb or TP. Given that tCa has 100% sensitivity for detecting hypocalcemia in this population it is recommended that all hypoalbuminemic and critically ill patients with low tCa should be evaluated with an iCa measurement.

  14. Labor force activity after 60

    DEFF Research Database (Denmark)

    Pedersen, Peder J.; Larsen, Mona


    In most OECD member countries labor force attachement has increased in recent years in the 60+ group. Focus in the paper is on the development in this area in Denmark, Norway and Sweden since the 1990s. The development in the same period in the German labor market is included as a frame of refere......In most OECD member countries labor force attachement has increased in recent years in the 60+ group. Focus in the paper is on the development in this area in Denmark, Norway and Sweden since the 1990s. The development in the same period in the German labor market is included as a frame...... in labor force participation is described based on register data and on labor force surveys along with indicators of cohort relevant changes in education and health. Focus in the paper includes also the gender aspect to accommodate stronger cohort effects for women than for men. The impact on labor force...... a brief survey of policy changes in the Scandinavian countries and Germany as other determinants of labor force participation in the 60 and older group....

  15. Tuning local calcium availability: cell-type-specific immobile calcium buffer capacity in hippocampal neurons. (United States)

    Matthews, Elizabeth A; Schoch, Susanne; Dietrich, Dirk


    It has remained difficult to ascribe a specific functional role to immobile or fixed intracellular calcium buffers in central neurons because the amount of these buffers is unknown. Here, we explicitly isolated the fixed buffer fraction by prolonged whole-cell patch-clamp dialysis and quantified its buffering capacity in murine hippocampal slices using confocal calcium imaging and the "added-buffer" approach. In dentate granule cells, the calcium binding ratio (κ) after complete washout of calbindin D28k (Cb), κfixed, displayed a substantial value of ∼100. In contrast, in CA1 oriens lacunosum moleculare (OLM) interneurons, which do not contain any known calcium-binding protein(s), κfixed amounted to only ∼30. Based on these values, a theoretical analysis of dendritic spread of calcium after local entry showed that fixed buffers, in the absence of mobile species, decrease intracellular calcium mobility 100- and 30-fold in granule cells and OLM cells, respectively, and thereby strongly slow calcium signals. Although the large κfixed alone strongly delays the spread of calcium in granule cells, this value optimizes the benefits of additionally expressing the mobile calcium binding protein Cb. With such high κfixed, Cb effectively increases the propagation velocity to levels seen in OLM cells and, contrary to expectation, does not affect the peak calcium concentration close to the source but sharpens the spatial and temporal calcium gradients. The data suggest that the amount of fixed buffers determines the temporal availability of calcium for calcium-binding partners and plays a pivotal role in setting the repertoire of cellular calcium signaling regimens.

  16. Diagnosis and assessment of skeletal related disease using calcium 41 (United States)

    Hillegonds, Darren J [Oakland, CA; Vogel, John S [San Jose, CA; Fitzgerald, Robert L [Encinitas, CA; Deftos, Leonard J [Del Mar, CA; Herold, David [Del Mar, CA; Burton, Douglas W [San Diego, CA


    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.

  17. Non-calcium desulphurisation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Qian Zhu [IEA Clean Coal Centre, London (United Kingdom)


    Flue gas desulphurisation (FGD) is traditionally based on limestone/lime sorbent. The majority of the installed FGD systems worldwide use limestone or lime as sorbent. However, technologies are rapidly evolving that allow desulphurisation in regions where there are limited resources of lime or limestone. These technologies provide alternatives to limestone/lime scrubbers for efficient and cost effective control of SO{sub 2} emissions from coal combustion. This report reviews the existing and emerging non-calcium based FGD processes as well as FGD technologies currently under development that apply new concepts and different approaches. It looks at the fundamentals and features of these processes, the recent technical advances and their applications in coal-fired power plants. The capital and operating costs of the processes are evaluated where information available. 66 refs., 15 figs., 10 tabs.

  18. Calcium-sensitive immunoaffinity chromatography

    DEFF Research Database (Denmark)

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


    Immunoaffinity chromatography is a powerful fractionation technique that has become indispensable for protein purification and characterization. However, it is difficult to retrieve bound proteins without using harsh or denaturing elution conditions, and the purification of scarce antigens...... to 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...... chromatography was superior to the traditional immunoaffinity chromatographies and resulted in a nine-fold improvement of the purification factor. The technique is applicable for the purification of proteins in complex mixtures by single-step fractionation without the denaturation of eluted antigens...

  19. [Study on the calcium-based sorbent for removal fluorine during coal combustion]. (United States)

    Li, Shu-ling; Qi, Qing-jie; Liu, Jian-zhong; Cao, Xin-yu; Zhou, Jun-hu; Cen, Ke-fa


    In the paper, the reaction of CaO-HF and fluorine removal mechanics at high temperature by blending calcium-based sorbents with coal during coal combustion were discussed, and test results about fluorine retention during coal combustion in fluidized bed and chain-grate furnace were reported. The results identified that lime and calcium-based sorbets developed can restratin the emission of fluorine during coal combustion. The efficiency of fluorine removal can reach 66.7%-70.0% at Ca/F 60-70 by blending lime with coal in fluidized bed combustion, and the efficiency of fluorine removal are between 57.32% and 75.19% by blending calcium-based sorbets with coal in chain-grate furnace combustion. Blending CaO or lime with coal during coal combustion can remove SO2 and HF simultaneously.

  20. The influence of calcium on technological properties and micropurity of steel castings

    Directory of Open Access Journals (Sweden)

    J. Hampl


    Full Text Available The paper analyzes the technological parameters, micro-purity and mechanical properties of castings of steel alloyed with calcium. The effect of calcium on the steel was analyzed on samples taken in the process of casting heavy castings and ingots of the weight of ranging from 40 000 to 60 000 kg. Samples for the determination of the liquidus temperature and the solidus temperature of cast steels were analysed using differential thermal analysis (DTA. The production of low alloyed steel grades was performed on the EAF - ASEA-SKF facilities and the production of highalloyed steels on the EAF - ASEA-SKF - SS-VOD facilities. The purity calcium was added into the steel by the injection of a stuffed profile.

  1. Calcium and vitamin D and risk of colorectal cancer: results from a large population-based case-control study in Newfoundland and Labrador and Ontario. (United States)

    Sun, Zhuoyu; Wang, Peizhong Peter; Roebothan, Barbara; Cotterchio, Michelle; Green, Roger; Buehler, Sharon; Zhao, Jinhui; Squires, Josh; Zhao, Jing; Zhu, Yun; Dicks, Elizabeth; Campbell, Peter T; Mclaughlin, John R; Parfrey, Patrick S


    Previous epidemiological studies have been suggestive but inconclusive in demonstrating inverse associations of calcium, vitamin D, dairy product intakes with risk of colorectal cancer (CRC). We conducted a large population-based comparison of such associations in Newfoundland and Labrador (NL) and Ontario (ON). A case control study design was used. Colorectal cancer cases were new CRC patients aged 20-74 years. Controls were a sex and age-group matched random sample of the population in each province. 1760 cases and 2481 controls from NL and ON were analyzed. Information on dietary intake and lifestyle was collected using self-administered food frequency and personal history questionnaires. Controls reported higher mean daily intakes of total calcium and total vitamin D than cases in both provinces. In ON, significant reduced CRC risk was associated with intakes of total calcium (OR of highest vs. lowest quintiles was 0.57, 95% CI 0.42-0.77, p(trend) = 0.03), total vitamin D (OR = 0.73, 95% CI 0.54-1.00), dietary calcium (OR = 0.76, 95% CI 0.60-0.97), dietary vitamin D (OR = 0.77, 95% CI 0.61-0.99), total dairy products and milk (OR = 0.78, 95% CI 0.60-1.00), calcium-containing supplements use (OR = 0.76). In NL, the inverse associations of calcium, vitamin D with CRC risk were most pronounced among calcium- or vitamin D-containing supplement users (OR = 0.67, 0.68, respectively). Results of this study add to the evidence that total calcium, dietary calcium, total vitamin D, dietary vitamin D, calcium- or vitamin D-containing supplement use may reduce the risk of CRC. The inverse associations of CRC risk with intakes of total dairy products and milk may be largely due to calcium and vitamin D.

  2. Dietary calcium from dairy and nondairy sources, and risk of symptomatic kidney stones. (United States)

    Taylor, Eric N; Curhan, Gary C


    Because of high correlations between dairy intake and total dietary calcium, previously reported associations between lower calcium intake and increased kidney stone risk represent de facto associations between milk products and risk. We examined associations between dietary calcium from nondairy and dairy sources, and symptomatic nephrolithiasis. We performed prospective studies in the Health Professionals Follow-up Study (HPFS) in 30,762 men, and in the Nurses' Health Study (NHS) I and II in 94,164 and 101,701 women, respectively. We excluded men 60 years old or older because we previously reported inverse associations between calcium intake and risk only in men younger than 60 years. Food frequency questionnaires were used to assess calcium intake every 4 years. We used Cox proportional hazards regression to adjust for age, body mass index, supplemental calcium, diet and other factors. We documented 5,270 incident kidney stones during the combined 56 years of followup. In participants in the highest vs the lowest quintile of nondairy dietary calcium the multivariate relative risk of kidney stones was 0.71 (95% CI 0.56-0.92, p for trend 0.007) in HPFS, 0.82 (95% CI 0.69-0.98, p trend 0.08) in NHS I and 0.74 (95% CI 0.63-0.87, p trend 0.002) in NHS II. When comparing the highest to the lowest quintile of dairy calcium, the multivariate relative risk was 0.77 (95% CI 0.63-0.95, p trend 0.01) for HPFS, 0.83 (95% CI 0.69-0.99, p trend 0.05) for NHS I and 0.76 (95% CI 0.65-0.88, p trend 0.001) for NHS II. Higher dietary calcium from nondairy or dairy sources is independently associated with a lower kidney stone risk. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  3. Qualitative discussion of prenucleation cluster role in crystallization of calcium carbonate under high concentration of magnesium based on experimental phenomena (United States)

    Zhang, Jie; Sun, Yuzhu; Yu, Jianguo


    Crystallization of calcium carbonate under high concentration of magnesium was studied. Interesting phenomena were observed. Approximately 80% of calcium ions stably existed in the solution up to 60 min after amorphous calcium carbonate was separated by centrifugation, and induction time was significantly affected by concentration and feeding rate of sodium carbonate when other operating conditions remained unchanged. Experiments and computer simulation have proved that prenucleation cluster exists during crystallization of calcium carbonate in solutions. This paper tried to figure out specific crystallization process of calcium carbonate under high concentration of magnesium, and to interpret unforeseen phenomena combining with the idea of prenucleation cluster. With regarding prenucleation cluster which can incorporate magnesium into its structure as amorphous calcium carbonate, most of the phenomena including significant influence of local mixing could be better understood. Prenucleation cluster played an important role in crystallization of calcium carbonate, which was related to the induction time, morphology and final product, thus more fundamental studies of prenucleation cluster structure and magnesium role in it should be done.

  4. Vitamin D deficiency and calcium intake in reference to increased body mass index in children and adolescents. (United States)

    Al-Musharaf, Sara; Al-Othman, Abdulaziz; Al-Daghri, Nasser M; Krishnaswamy, Soundararajan; Yusuf, Deqa S; Alkharfy, Khalid M; Al-Saleh, Yousef; Al-Attas, Omar S; Alokail, Majed S; Moharram, Osama; Yakout, Sobhy; Sabico, Shaun; Chrousos, George P


    Vitamin D deficiency has been linked to several chronic diseases in adults. Studies focusing on children and adolescents, however, are limited. In this randomized cross-sectional study, we aimed to determine the prevalence of vitamin D deficiency and its relationship with childhood obesity and dietary calcium intake among a population of healthy urban Saudi children and adolescents. To achieve this, 331 randomly selected Saudi children (53.8% females and 46.2% males) aged 6-17 years were included. Demographic, medical, and dietary information were collected; anthropometrics were measured. Levels of serum fasting glucose, lipid profile, 25(OH) D, and for albumin corrected calcium were analyzed. Vitamin D deficiency was noted in all subjects, with girls having significantly lower vitamin D levels than boys. Mean calcium intake was found to be 60% of the required dietary allowance (RDA), while the mean vitamin D intake was 23% of RDA. Vitamin D status and calcium intake were comparable in both normal and overweight/obese children and adolescents. Vitamin D status was highest among children who had calcium intake >800 mg/day. In adolescents there was insignificant but decreasing trend in BMI, which was observed to be highest among those whose calcium intake was 800 mg/day. results from this study suggest the importance of vitamin D fortification and increased dietary calcium in the Saudi diet to meet RDA requirements and avoid onset of vitamin D deficiency-related diseases in Saudi children and adolescents.


    Directory of Open Access Journals (Sweden)

    Happy Mulyani


    Full Text Available The objectives of this research are to study about influence of calcium hypochlorite dosage adjustment on tapioca wastewater chlorination toward efficiency of activated sludge treatment especially at MLVSS profile and percentage of COD removal. This research mainly divided into pre-chlorination and activated sludge treatment. Pre-chlorination taken place for 60 minutes at pH 8. The variation of calcium hypochlorite dosages which used are 58, 59, and 60 mg/L. Pre-chlorination effluent with no free chlorine residual then becomes activated sludge treatment influent. Sampling has done each aeration time interval 0, 2, 4, and 6 hour for analysis of COD and MLVSS content. Research result generally shows that addition of aeration time for each variation of calcium hypochlorite dosage will increase MLVSS and decrease COD content. Smallest value of COD effluent could achieved in the activated sludge treatment with calcium hipochlorite dosage 60 mg/L addition at influent during 4 hours aeration time. Addition of 58 mg/l calcium hypochlorite results highest MLVSS and percentage of COD removal.

  6. Relationship of calcium absorption with 25(OH)D and calcium intake in children with rickets. (United States)

    Thacher, Tom D; Abrams, Steven A


    Nutritional rickets has long been considered a disease caused by vitamin D deficiency, but recent data indicate that inadequate dietary calcium intake is an important cause of rickets, particularly in tropical countries. Children with rickets due to calcium deficiency do not have very low 25(OH)D concentrations, and serum 1,25(OH)(2) D values are markedly elevated. Studies of Nigerian children with rickets demonstrated they have high fractional calcium absorption. A high-phytate diet was demonstrated to increase calcium absorption compared with the fasting state, and enzymatic dephytinization did not significantly improve calcium absorption. When given vitamin D, children with rickets have a marked increase in 1,25(OH)(2) D concentrations without any change in fractional calcium absorption. No positive relationship was found between fractional calcium absorption and serum 25(OH)D concentrations in children on low-calcium diets. More research is needed to understand the interaction between calcium and vitamin D and the role of vitamin D in calcium absorption. © 2010 International Life Sciences Institute.

  7. Calcium phosphate scaffold from biogenic calcium carbonate by fast ambient condition reactions (United States)

    Dutta, Abhishek; Fermani, Simona; Arjun Tekalur, Srinivasan; Vanderberg, Abigail; Falini, Giuseppe


    Calcium phosphate biogenic materials are biocompatible and promote bioactivity and osteoconductivity, which implies their natural affinity and tendency to bond directly to bones subsequently replacing the host bone after implantation owing to its biodegradability. Calcium hydrogen phosphate dihydrate, CaHPO 4·2H 2O, is known to be a nucleation precursor, in aqueous solutions, for apatitic calcium phosphates and, hence, a potential starting material for bone substitutes. Numerous approaches, via hydrothermal and ambient synthetic routes, have been used to produce calcium phosphate from biogenic calcium carbonate, taking advantage of the peculiar architecture and composition of the latter. In this article, the lamellar region of the cuttlefish bone ( Sepia officinalis) was used as a framework for the organized deposition of calcium phosphate crystals, at ambient conditions via a fast procedure involving an amorphous calcium carbonate intermediate, and ending with a conversion to calcium phosphate and a fixation procedure, thereby resulting in direct conversion of biogenic calcium carbonate into calcium phosphates at ambient conditions from the scale of months to hours.

  8. Transgenic plants with increased calcium stores (United States)

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


    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.

  9. In vitro antioxidant properties of calcium dobesilate. (United States)

    Brunet, J; Farine, J C; Garay, R P; Hannaert, P


    Calcium dobesilate, a vascular protective agent, was tested in vitro for its scavenging action against oxygen free radicals. Calcium dobesilate was as potent as rutin to scavenge hydroxyl radicals (IC50 = 1.1 vs 0.7 microM, respectively). It was also able to scavenge superoxide radicals, but with 23 times less potency than rutin (IC50 = 682 vs 30 microM, respectively). Calcium dobesilate significantly reduced platelet activating factor (PAF)-induced chemiluminescence in human PMN cells and lipid peroxidation by oxygen free radicals in human erythrocyte membranes, although these actions required calcium dobesilate concentrations > or = 50 microM. Finally, in cultured bovine aortic endothelial cells, magnesium dobesilate reduced the increase in cytosolic free calcium induced by hydrogen peroxide and inhibited phenazine methosulfate-induced cell potassium loss. In conclusion, calcium dobesilate was effective in scavenging hydroxyl radicals in vitro, at therapeutically relevant concentrations. Conversely, higher concentrations of the compound were required to scavenge superoxide radicals or to protect the cells against the deleterious effects of intracellular reactive oxygen species. Further studies in vivo are required to determine if these antioxidant properties of calcium dobesilate can play a role in its vascular protective mechanisms.

  10. Intracellular sphingosine releases calcium from lysosomes (United States)

    Höglinger, Doris; Haberkant, Per; Aguilera-Romero, Auxiliadora; Riezman, Howard; Porter, Forbes D; Platt, Frances M; Galione, Antony; Schultz, Carsten


    To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC. DOI: PMID:26613410

  11. Calcium content of different compositions of gallstones and pathogenesis of calcium carbonate gallstones. (United States)

    Yu, Ji-Kuen; Pan, Huichin; Huang, Shing-Moo; Huang, Nan-Lan; Yao, Chung-Chin; Hsiao, Kuang-Ming; Wu, Chew-Wun


    Our aim was to investigate the calcium content of different gallstone compositions and the pathogenic mechanisms of calcium carbonate gallstones. Between August 2001 and July 2007, gallstones from 481 patients, including 68 calcium carbonate gallstones, were analyzed for total calcium content. Gallbladder bile samples from 33 cases and six controls were analyzed for pH, carbonate anion level, free-ionized calcium concentration and saturation index for calcium carbonate. Total calcium content averaged 75.6 %, 11.8 %, and 4.2 % for calcium carbonate, calcium bilirubinate and cholesterol gallstones. In 29.4 % of patients, chronic and/or intermittent cystic duct obstructions were caused by polypoid lesions in the neck region and 70.6 % were caused by stones. A total of 82 % of patients had chronic low-grade inflammation of the gallbladder wall and 18.0 % had acute inflammatory exacerbations. In the bile, we found the mean pH, mean carbonate anion, free-ionized calcium concentrations, and mean saturation index for calcium carbonate to be elevated in comparison to controls. From our study, we found chronic and/or intermittent cystic duct obstructions and low-grade GB wall inflammation lead to GB epithelium hydrogen secretion dysfunction. Increased calcium ion efflux into the GB lumen combined with increased carbonate anion presence increases SI_CaCO(3) from 1 to 22.4. Thus, in an alkaline milieu with pH 7.8, calcium carbonate begins to aggregate and precipitate. Copyright © 2012. Published by Elsevier B.V.

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

    Directory of Open Access Journals (Sweden)

    Nishiura J.L.


    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.

  13. Too Much Sodium PSA (:60)

    Centers for Disease Control (CDC) Podcasts


    This 60 second PSA is based on the February 2012 CDC Vital Signs report. Ninety percent of Americans age two and older eat too much sodium which can increase your risk for high blood pressure and often leads to heart disease and stroke, two leading causes of death in the US. Learn several small steps you can take to reduce the amount of sodium in your diet.  Created: 2/7/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 2/7/2012.

  14. Serum calcium and the calcium-sensing receptor polymorphism rs17251221 in relation to coronary heart disease, type 2 diabetes, cancer and mortality: the Tromsø Study. (United States)

    Jorde, Rolf; Schirmer, Henrik; Njølstad, Inger; Løchen, Maja-Lisa; Bøgeberg Mathiesen, Ellisiv; Kamycheva, Elena; Figenschau, Yngve; Grimnes, Guri


    Serum calcium measured in 27,158 subjects in 1994 and the calcium-sensing receptor polymorphism rs17251221 genotyped in 9,404 subjects were related to cardiovascular risk factors, incident myocardial infarction (MI), type 2 diabetes (T2DM), cancer and death during follow-up until 2008-2010. In a Cox regression model with adjustment for age, gender, smoking and body mass index, subjects with serum calcium 2.50-2.60 mmol/L had a significantly increased risk of incident MI [n = 1,802, hazards ratio (HR) 1.40, 95 % confidence interval (CI) 1.18, 1.66] and T2DM (n = 705, HR 1.49, 95 % CI 1.15, 1.94) and a significantly reduced risk of cancer (n = 2,222, HR 0.73, 95 % CI 0.62, 0.86) as compared to subjects with serum calcium 2.20-2.29 mmol/L. For rs17251221 there was a mean difference in serum calcium of 0.05 mmol/L between major and minor homozygote genotypes. No consistent, significant relation between rs17251221 and risk factors or the major hard endpoints were found. The minor homozygote genotype (high serum calcium) had a significant twofold increased risk (HR 2.32, 95 % CI 1.24, 4.36) for prostate cancer, as compared to the major homozygote. This may be clinically important if confirmed in other cohorts.

  15. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture* (United States)

    Mauceri, Daniela; Hagenston, Anna M.; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar


    Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. PMID:26231212

  16. Protein-Mediated Precipitation of Calcium Carbonate

    Directory of Open Access Journals (Sweden)

    Izabela Polowczyk


    Full Text Available Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, and Fourier transform infrared spectroscopy (FTIR measurements. In addition, the turbidity of the reaction solution was acquired to monitor the kinetics of the calcium carbonate structure’s growth in the investigated system. In this study, samples of CaCO3 particles obtained with individual proteins, such as ovalbumin, lysozyme, and a mixture of the proteins, were characterized and compared with a control sample, i.e., synthesized without proteins. The obtained data indicated that the addition of ovalbumin to the reaction changed the morphology of crystals from rhombohedral to ‘stack-like’ structures. Lysozyme, however, did not affect the morphology of calcium carbonate, yet the presence of the protein mixture led to the creation of more complex composites in which the calcium carbonate crystals were constructed in protein matrices formed by the ovalbumin-lysozyme interaction. It was also observed that in the protein mixture, ovalbumin has a major influence on the CaCO3 formation through a strong interaction with calcium ions, which leads to the coalescence and creation of a steric barrier reducing particle growth. The authors proposed a mechanism of calcium carbonate grain growth in the presence of both proteins, taking into account the interaction of calcium ions with the protein.

  17. Protein-Mediated Precipitation of Calcium Carbonate (United States)

    Polowczyk, Izabela; Bastrzyk, Anna; Fiedot, Marta


    Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. In addition, the turbidity of the reaction solution was acquired to monitor the kinetics of the calcium carbonate structure’s growth in the investigated system. In this study, samples of CaCO3 particles obtained with individual proteins, such as ovalbumin, lysozyme, and a mixture of the proteins, were characterized and compared with a control sample, i.e., synthesized without proteins. The obtained data indicated that the addition of ovalbumin to the reaction changed the morphology of crystals from rhombohedral to ‘stack-like’ structures. Lysozyme, however, did not affect the morphology of calcium carbonate, yet the presence of the protein mixture led to the creation of more complex composites in which the calcium carbonate crystals were constructed in protein matrices formed by the ovalbumin-lysozyme interaction. It was also observed that in the protein mixture, ovalbumin has a major influence on the CaCO3 formation through a strong interaction with calcium ions, which leads to the coalescence and creation of a steric barrier reducing particle growth. The authors proposed a mechanism of calcium carbonate grain growth in the presence of both proteins, taking into account the interaction of calcium ions with the protein. PMID:28774065

  18. Safety of calcium dobesilate in chronic venous disease, diabetic retinopathy and haemorrhoids. (United States)

    Allain, Hervé; Ramelet, Albert A; Polard, Elisabeth; Bentué-Ferrer, Danièle


    The aim of the present review is to consider the adverse effects and the safety profile of calcium dobesilate. Calcium dobesilate (Doxium) is a veno-tonic drug, which is widely prescribed in more than 60 countries from Europe, Latin America, Asia and the Middle East for three main indications: chronic venous disease, diabetic retinopathy and the symptoms of haemorrhoidal attack. Data sources used for this review comprise the international literature (1970-2003), a postmarketing surveillance (PMS) report for calcium dobesilate from OM Pharma (Geneva, Switzerland) covering the period 1974-1998, and periodic safety update reports (PSUR) covering the period 1995-2003 from the French Regulatory authorities pharmacovigilance database and OM Pharma. Data from the PMS report for 1974-1998 indicated that adverse events with calcium dobesilate did not occur very frequently and had the following distribution in terms of frequency: fever (26%), gastrointestinal disorders (12.5%), skin reactions (8.2%), arthralgia (4.3%), and agranulocytosis (4.3%). No deaths were attributed to calcium dobesilate in the PMS report. Using data on product use in the Swiss Compendium we estimated the prevalence of agranulocytosis to be 0.32 cases/million treated patients, i.e. ten times less than the calculated prevalence of agranulocytosis in the general population. Most adverse events are type B, i.e. rare and unrelated to the pharmacological properties of calcium dobesilate. This review concludes that the risk of an adverse effect with calcium dobesilate 500-1500 mg/day is low and constant over time. The recently raised problem of agranulocytosis (a total of 13 known cases drawn from all data sources) appears to be related to methodological bias. Such a review reinforces the need for a strong international pharmacovigilance organisation using similar methods to detect and analyse the adverse effects of drugs.

  19. Dietary calcium from dairy and non-dairy sources and risk of symptomatic kidney stones (United States)

    Taylor, Eric N.; Curhan, Gary C.


    Purpose Because of high correlations between dairy intake and total dietary calcium, previously reported associations between lower calcium intake and increased kidney stone risk represent de facto associations between milk products and risk. We sought to examine associations between dietary calcium from non-dairy and dairy sources and symptomatic nephrolithiasis. Materials and Methods We conducted prospective studies in the Health Professionals Follow-up Study (HPFS; N=30,762 men), the Nurses’ Health Study I (NHS I; N=94,164 women), and the Nurses’ Health Study II (NHS II; N=101,701 women). We excluded men ≥ 60 years old because we previously reported inverse associations between calcium intake and risk only in men kidney stones over a combined 56 years of follow-up. For participants in the highest compared to lowest quintile of non-dairy dietary calcium, the multivariable relative risks of kidney stones were 0.71 (95% CI 0.56–0.92; P for trend 0.007) for HPFS, 0.82 (0.69–0.98; P trend 0.08) for NHS I, and 0.74 (0.63–0.87; P trend 0.002) for NHS II. The multivariable relative risks comparing highest to lowest quintile of dairy calcium were 0.77 (0.63–0.95; P trend 0.01) for HPFS, 0.83 (0.69–0.99; P trend 0.05) for NHS I, and 0.76 (0.65–0.88; P trend 0.001) for NHS II. Conclusions Higher dietary calcium from either non-dairy or dairy sources is independently associated with lower kidney stone risk. PMID:23535174

  20. Technical description of the NTK1500/60-60

    Energy Technology Data Exchange (ETDEWEB)

    Soendergaard, Henrik


    The 1.5 MW turbine is a tree blade upwind rotor with a hub height of 60 m. The tube tower has a diameter of 3.8 m in top and 4.2 m at the base and is the world largest commercial three blade stall regulated wind turbine. The develeopment project is subsidized by EU under the THERMIE and JOULE II programs for demonstration for research respective development. The design process resulted in a smoothly formed nacelle placed on a double coned tower which `firmly holds` on to the nacelle. The overall design was finished in August 1994 and the turbine was erected in late August 1995 and set into commissioning in September 1995. The measuring program was started in September 1995 and will be completed in December 1997. (au)

  1. Calcium Signaling Is Required for Erythroid Enucleation.

    Directory of Open Access Journals (Sweden)

    Christina B Wölwer

    Full Text Available Although erythroid enucleation, the property of erythroblasts to expel their nucleus, has been known for 7ore than a century, surprisingly little is known regarding the molecular mechanisms governing this unique developmental process. Here we show that similar to cytokinesis, nuclear extrusion requires intracellular calcium signaling and signal transduction through the calmodulin (CaM pathway. However, in contrast to cytokinesis we found that orthochromatic erythroblasts require uptake of extracellular calcium to enucleate. Together these functional studies highlight a critical role for calcium signaling in the regulation of erythroid enucleation.

  2. Coronary artery calcium score: current status (United States)

    Neves, Priscilla Ornellas; Andrade, Joalbo; Monção, Henry


    The coronary artery calcium score plays an Important role In cardiovascular risk stratification, showing a significant association with the medium- or long-term occurrence of major cardiovascular events. Here, we discuss the following: protocols for the acquisition and quantification of the coronary artery calcium score by multidetector computed tomography; the role of the coronary artery calcium score in coronary risk stratification and its comparison with other clinical scores; its indications, interpretation, and prognosis in asymptomatic patients; and its use in patients who are symptomatic or have diabetes. PMID:28670030

  3. Adhesion property of epoxidized natural rubber (ENR-based adhesives containing calcium carbonate

    Directory of Open Access Journals (Sweden)


    Full Text Available The adhesion property (i.e. viscosity, loop tack and peel strength of epoxidized natural rubber (ENR 25 and ENR 50 grade-based pressure-sensitive adhesive was studied in the presence of calcium carbonate. The range of calcium carbonate loaded was from 10 to 50 parts per hundred parts of rubber (phr. Coumarone-indene resin was used as the tackifier and its concentration was fixed at 80 phr. Toluene was chosen as the solvent throughout the investigation. The substrates (PET film/paper were coated with the adhesive using a SHEEN hand coater at a coating thickness of 60 µm. Viscosity of the adhesive was measured by a HAAKE Rotary Viscometer whereas loop tack and peel strength were determined by a Llyod Adhesion Tester operating at 30 cm/min. Results show that viscosity of ENR-based adhesives increases gradually with increase in calcium carbonate loading due to the concentration effect of the filler. However, for loop tack and peel strength, it passes through a maximum at 30 phr calcium carbonate, an observation which is attributed to the optimum wettability of adhesive on the substrate at this adhesive composition. ENR 25-based adhesive consistently exhibits higher adhesion property than ENR 50 for all calcium carbonate loadings studied.

  4. Low temperature pyrolysis of coal or oil shale in the presence of calcium compounds (United States)

    Khan, M. Rashid


    A coal pyrolysis technique or process is described in which particulate coal is pyrolyzed in the presence of about 5 to 21 wt. % of a calcium compound selected from calcium oxide, calcined (hydrate) dolomite, or calcined calcium hydrate to produce a high quality hydrocarbon liquid and a combustible product gas which are characterized by low sulfur content. The pyrolysis is achieved by heating the coal-calcium compound mixture at a relatively slow rate at a temperature of about to C. over a duration of about 10 to 60 minutes in a fixed or moving bed reactor. The gas exhibits an increased yield in hydrogen and C.sub.1 -C.sub.8 hydrocarbons and a reduction in H.sub.2 S over gas obtainable by pyrolyzing cola without the calcium compound. The liquid product obtained is of a sufficient quality to permit its use directly as a fuel and has a reduced sulfur and oxygen content which inhibits polymerization during storage.

  5. Cost-effectiveness of vitamin D and calcium supplementation in the treatment of elderly women and men with osteoporosis. (United States)

    Hiligsmann, Mickaël; Ben Sedrine, Wafa; Bruyère, Olivier; Evers, Silvia M; Rabenda, Véronique; Reginster, Jean-Yves


    The supplementation with vitamin D and calcium has been recommended for elderly, specifically those with increased risk of fractures older than 65 years. This study aims to assess the cost-effectiveness of vitamin D and calcium supplementation in elderly women and men with osteoporosis and therefore to assess if this recommendation is justified in terms of cost-effectiveness. A validated model for economic evaluations in osteoporosis was used to estimate the cost per quality-adjusted life-year (QALY) gained of vitamin D/calcium supplementation compared with no treatment. The model was populated with cost and epidemiological data from a Belgian health-care perspective. Analyses were conducted in women and men with a diagnosis of osteoporosis (i.e. bone mineral density T-score ≤-2.5). A literature search was conducted to describe the efficacy of vitamin D and calcium in terms of fracture risk reduction. The cost per QALY gained of vitamin D/calcium supplementation was estimated at €40 578 and €23 477 in women and men aged 60 years, respectively. These values decreased to €7912 and €10 250 at the age of 70 years and vitamin D and calcium supplementation was cost-saving at the age of 80 years, meaning that treatment cost was less than the costs of treating osteoporotic fractures of the no-treatment group. This study suggests that vitamin D and calcium supplementation is cost-effective for women and men with osteoporosis aged over 60 years. From an economic perspective, vitamin D and calcium should therefore be administrated in these populations including those also taking other osteoporotic treatments. © The Author 2014. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

  6. Electrical resistivity and stoichiometry of KxC60, RbxC60, and CsxC60 films

    NARCIS (Netherlands)

    Haddon, R.C.; Perel, A.S.; Morris, R.C.; Chang, S.-H.; Fiory, A.T.; Hebard, A.F.; Palstra, T.T.M.; Kochanski, G.P.


    Electrical resistance measurements as a function of stoichiometry have been carried out on KxC60, RbxC60 and CsxC60 thin films for 060, ρmin=4×10-3 Ω cm (60°C), Rb3C60, ρmin=4×10-3 Ω cm, and Cs1C60, ρmin = 7×10-2 Ω cm. All of the annealed

  7. 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)


    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.

  8. Effects of Adding Chymosin to Milk on Calcium Homeostasis

    DEFF Research Database (Denmark)

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


    either chymosin or similar placebo was added. Compared with placebo, chymosin did not affect 24-h urinary calcium, calcium/creatinine ratio, plasma parathyroid hormone, calcitonin or ionized calcium levels. However, during the first 4 h after intake of milk with chymosin, urinary calcium-creatinine ratio...

  9. Does calcium constrain reproductive activity in insectivorous bats ...

    African Journals Online (AJOL)

    Insects are a poor source of dietary calcium and since they are seasonally abundant, it has been suggested that calcium availability may play a significant role in controlling the timing of reproduction in insectivorous bats. To assess the possible role of dietary calcium, we have measured bone calcium concentrations in ...

  10. Model of intracellular calcium cycling in ventricular myocytes. (United States)

    Shiferaw, Y; Watanabe, M A; Garfinkel, A; Weiss, J N; Karma, A


    We present a mathematical model of calcium cycling that takes into account the spatially localized nature of release events that correspond to experimentally observed calcium sparks. This model naturally incorporates graded release by making the rate at which calcium sparks are recruited proportional to the whole cell L-type calcium current, with the total release of calcium from the sarcoplasmic reticulum (SR) being just the sum of local releases. The dynamics of calcium cycling is studied by pacing the model with a clamped action potential waveform. Experimentally observed calcium alternans are obtained at high pacing rates. The results show that the underlying mechanism for this phenomenon is a steep nonlinear dependence of the calcium released from the SR on the diastolic SR calcium concentration (SR load) and/or the diastolic calcium level in the cytosol, where the dependence on diastolic calcium is due to calcium-induced inactivation of the L-type calcium current. In addition, the results reveal that the calcium dynamics can become chaotic even though the voltage pacing is periodic. We reduce the equations of the model to a two-dimensional discrete map that relates the SR and cytosolic concentrations at one beat and the previous beat. From this map, we obtain a condition for the onset of calcium alternans in terms of the slopes of the release-versus-SR load and release-versus-diastolic-calcium curves. From an analysis of this map, we also obtain an understanding of the origin of chaotic dynamics.

  11. The Incredible, Embryological Egg: Calcium and Strontium Isotopes Recapitulate Ontogeny (United States)

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


    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

  12. Vitamin D with calcium reduces mortality

    DEFF Research Database (Denmark)

    Rejnmark, Lars; Avenell, Alison; Masud, Tahir


    Introduction:Vitamin D may affect multiple health outcomes. If so, an effect on mortality is to be expected. Using pooled data from randomized controlled trials, we performed individual patient data (IPD) and trial level meta-analyses to assess mortality among participants randomized to either...... 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....... vitamin D alone or vitamin D with calcium.Subjects and Methods:Through a systematic literature search, we identified 24 randomized controlled trials reporting data on mortality in which vitamin D was given either alone or with calcium. From a total of 13 trials with more than 1000 participants each, eight...

  13. Excitons in solid C60

    Energy Technology Data Exchange (ETDEWEB)

    Shirley, Eric L.; Benedict, Lorin X.; Louie, Steven G.


    Exciton levels in undoped, solid C60 are calculated using a model Hamiltonian. We find excitation energies of 1.58 and 1.30 eV for the lowest singlet and triplet exciton, respectively, in comparison with the measured energies of 1.83 and 1.55 eV. Singlet and triplet states have similar energy diagrams, wherein exciton states having T{sub 2g}, T{sub 1g},G{sub g}, and H{sub g} symmetries are separated by up to several tenths of an electron volt. As a function of crystal momentum, exciton energies exhibit dispersion from 20 to 40 meV. Theoretical pressure derivatives of exciton energies are presented.

  14. Calcium Signaling and Cardiac Arrhythmias. (United States)

    Landstrom, Andrew P; Dobrev, Dobromir; Wehrens, Xander H T


    There has been a significant progress in our understanding of the molecular mechanisms by which calcium (Ca2+) ions mediate various types of cardiac arrhythmias. A growing list of inherited gene defects can cause potentially lethal cardiac arrhythmia syndromes, including catecholaminergic polymorphic ventricular tachycardia, congenital long QT syndrome, and hypertrophic cardiomyopathy. In addition, acquired deficits of multiple Ca2+-handling proteins can contribute to the pathogenesis of arrhythmias in patients with various types of heart disease. In this review article, we will first review the key role of Ca2+ in normal cardiac function-in particular, excitation-contraction coupling and normal electric rhythms. The functional involvement of Ca2+ in distinct arrhythmia mechanisms will be discussed, followed by various inherited arrhythmia syndromes caused by mutations in Ca2+-handling proteins. Finally, we will discuss how changes in the expression of regulation of Ca2+ channels and transporters can cause acquired arrhythmias, and how these mechanisms might be targeted for therapeutic purposes. © 2017 American Heart Association, Inc.

  15. Morphological Investigation of Calcium Carbonate during Ammonification-Carbonization Process of Low Concentration Calcium Solution

    Directory of Open Access Journals (Sweden)

    Huaigang Cheng


    Full Text Available Ultrafine calcium carbonate is a widely used cheap additive. The research is conducted in low degree supersaturation solution in order to study the polymorphic phases’ change and its factors of the calcium carbonate precipitate in the ammonification-carbonization process of the solution with calcium. Fine particles of calcium carbonate are made in the solution containing 0.015 mol/L of Ca2+. Over 98% of the calcium carbonate precipitate without ammonification resembles the morphology of calcite, while the introduction of ammonia can benefit the formation of vaterite. It was inferred that the main cause should be serious partial oversaturation or steric effects. Ammonia also helps to form the twin spherical calcium carbonate. However, particles formed in the process of ammonification-carbonization in solution with low concentration degree of calcium are not even with a scale of the particle diameter from 5 to 12 μm. Inorganic salts, alcohol, or organic acid salts have significant controlling effect on the particle diameter of calcium carbonate and can help to decrease the particle diameter to about 3 μm. Anionic surfactants can prevent the conglobation of calcium carbonate particles and shrink its diameter to 500 nm–1 μm.

  16. Calcium-induced calcium release supports recruitment of synaptic vesicles in auditory hair cells. (United States)

    Castellano-Muñoz, Manuel; Schnee, Michael E; Ricci, Anthony J


    Hair cells from auditory and vestibular systems transmit continuous sound and balance information to the central nervous system through the release of synaptic vesicles at ribbon synapses. The high activity experienced by hair cells requires a unique mechanism to sustain recruitment and replenishment of synaptic vesicles for continuous release. Using pre- and postsynaptic electrophysiological recordings, we explored the potential contribution of calcium-induced calcium release (CICR) in modulating the recruitment of vesicles to auditory hair cell ribbon synapses. Pharmacological manipulation of CICR with agents targeting endoplasmic reticulum calcium stores reduced both spontaneous postsynaptic multiunit activity and the frequency of excitatory postsynaptic currents (EPSCs). Pharmacological treatments had no effect on hair cell resting potential or activation curves for calcium and potassium channels. However, these drugs exerted a reduction in vesicle release measured by dual-sine capacitance methods. In addition, calcium substitution by barium reduced release efficacy by delaying release onset and diminishing vesicle recruitment. Together these results demonstrate a role for calcium stores in hair cell ribbon synaptic transmission and suggest a novel contribution of CICR in hair cell vesicle recruitment. We hypothesize that calcium entry via calcium channels is tightly regulated to control timing of vesicle fusion at the synapse, whereas CICR is used to maintain a tonic calcium signal to modulate vesicle trafficking. Copyright © 2016 the American Physiological Society.

  17. The effect of root dentin conditioning protocols on the push-out bond strength of three calcium silicate sealers

    NARCIS (Netherlands)

    Neelakantan, P.; Nandagopal, M.; Shemesh, H.; Wesselink, P.R.


    Objectives: To compare the effects of irrigation protocols on the push-out bond strength of calcium silicate materials at two different time periods (7-days and 3-months). Materials and methods: Root canals (n=300) were irrigated with one of the following (n=60): group 1 (3% NaOCl-17% EDTA); group 2

  18. Fractal aspects of calcium binding protein structures

    Energy Technology Data Exchange (ETDEWEB)

    Isvoran, Adriana [West University of Timisoara, Department of Chemistry, Pestalozzi 16, 300115 Timisoara (Romania)], E-mail:; Pitulice, Laura [West University of Timisoara, Department of Chemistry, Pestalozzi 16, 300115 Timisoara (Romania); Craescu, Constantin T. [INSERM U759/Institute Curie-Recherche, Centre Universitaire Paris-Sud, Batiment 112, 91405 Orsay (France); Chiriac, Adrian [West University of Timisoara, Department of Chemistry, Pestalozzi 16, 300115 Timisoara (Romania)


    The structures of EF-hand calcium binding proteins may be classified into two distinct groups: extended and compact structures. In this paper we studied 20 different structures of calcium binding proteins using the fractal analysis. Nine structures show extended shapes, one is semi-compact and the other 10 have compact shapes. Our study reveals different fractal characteristics for protein backbones belonging to different structural classes and these observations may be correlated to the physicochemical forces governing the protein folding.

  19. Understanding calcium dynamics experiments and theory

    CERN Document Server

    Malchow, Dieter


    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.

  20. Analytical models of calcium binding in a calcium channel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jinn-Liang [Department of Applied Mathematics, National Hsinchu University of Education, Hsinchu 300, Taiwan (China); Eisenberg, Bob [Department of Molecular Biophysics and Physiology, Rush University, Chicago, Illinois 60612 (United States)


    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{sup +} and Ca{sup 2+} for [CaCl{sub 2}] ranging from 10{sup −8} to 10{sup −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.

  1. Contribution of calcium oxalate to soil-exchangeable calcium (United States)

    Dauer, Jenny M.; Perakis, Steven S.


    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.

  2. Self-Setting Calcium Orthophosphate Formulations (United States)

    Dorozhkin, Sergey V.


    In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are bioactive and biodegradable grafting bioceramics in the form of a powder and a liquid. After mixing, both phases form pastes, which set and harden forming either a non-stoichiometric calcium deficient hydroxyapatite or brushite. Since both of them are remarkably biocompartible, bioresorbable and osteoconductive, self-setting calcium orthophosphate formulations appear to be promising bioceramics for bone grafting. Furthermore, such formulations possess excellent molding capabilities, easy manipulation and nearly perfect adaptation to the complex shapes of bone defects, followed by gradual bioresorption and new bone formation. In addition, reinforced formulations have been introduced, which might be described as calcium orthophosphate concretes. The discovery of self-setting properties opened up a new era in the medical application of calcium orthophosphates and many commercial trademarks have been introduced as a result. Currently such formulations are widely used as synthetic bone grafts, with several advantages, such as pourability and injectability. Moreover, their low-temperature setting reactions and intrinsic porosity allow loading by drugs, biomolecules and even cells for tissue engineering purposes. In this review, an insight into the self-setting calcium orthophosphate formulations, as excellent bioceramics suitable for both dental and bone grafting applications, has been provided. PMID:24956191

  3. Calcium signaling in human pluripotent stem cells. (United States)

    Apáti, Ágota; Berecz, Tünde; Sarkadi, Balázs


    Human pluripotent stem cells provide new tools for developmental and pharmacological studies as well as for regenerative medicine applications. Calcium homeostasis and ligand-dependent calcium signaling are key components of major cellular responses, including cell proliferation, differentiation or apoptosis. Interestingly, these phenomena have not been characterized in detail as yet in pluripotent human cell sates. Here we review the methods applicable for studying both short- and long-term calcium responses, focusing on the expression of fluorescent calcium indicator proteins and imaging methods as applied in pluripotent human stem cells. We discuss the potential regulatory pathways involving calcium responses in hPS cells and compare these to the implicated pathways in mouse PS cells. A recent development in the stem cell field is the recognition of so called "naïve" states, resembling the earliest potential forms of stem cells during development, as well as the "fuzzy" stem cells, which may be alternative forms of pluripotent cell types, therefore we also discuss the potential role of calcium homeostasis in these PS cell types. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. High speed two-photon imaging of calcium dynamics in dendritic spines: consequences for spine calcium kinetics and buffer capacity

    NARCIS (Netherlands)

    Cornelisse, L.N.; van Elburg, R.A.J.; Meredith, R.M.; Yuste, R.; Mansvelder, H.D.


    Rapid calcium concentration changes in postsynaptic structures are crucial for synaptic plasticity. Thus far, the determinants of postsynaptic calcium dynamics have been studied predominantly based on the decay kinetics of calcium transients. Calcium rise times in spines in response to single action

  5. High Speed Two-Photon Imaging of Calcium Dynamics in Dendritic Spines: : Consequences for Spine Calcium Kinetics and Buffer Capacity

    NARCIS (Netherlands)

    van Elburg, R.A.J.; Cornelisse, L.N; Meredith, R.M; Yuste, R; Mansvelder, H.D


    Rapid calcium concentration changes in postsynaptic structures are crucial for synaptic plasticity. Thus far, the determinants of postsynaptic calcium dynamics have been studied predominantly based on the decay kinetics of calcium transients. Calcium rise times in spines in response to single action

  6. Oral calcium carbonate affects calcium but not phosphorus balance in stage 3-4 chronic kidney disease. (United States)

    Hill, Kathleen M; Martin, Berdine R; Wastney, Meryl E; McCabe, George P; Moe, Sharon M; Weaver, Connie M; Peacock, Munro


    Patients with chronic kidney disease (CKD) are given calcium carbonate to bind dietary phosphorus, reduce phosphorus retention, and prevent negative calcium balance; however, data are limited on calcium and phosphorus balance during CKD to support this. Here, we studied eight patients with stage 3 or 4 CKD (mean estimated glomerular filtration rate 36 ml/min) who received a controlled diet with or without a calcium carbonate supplement (1500 mg/day calcium) during two 3-week balance periods in a randomized placebo-controlled cross-over design. All feces and urine were collected during weeks 2 and 3 of each balance period and fasting blood, and urine was collected at baseline and at the end of each week. Calcium kinetics were determined using oral and intravenous (45)calcium. Patients were found to be in neutral calcium and phosphorus balance while on the placebo. Calcium carbonate supplementation produced positive calcium balance, did not affect phosphorus balance, and produced only a modest reduction in urine phosphorus excretion compared with placebo. Calcium kinetics demonstrated positive net bone balance but less than overall calcium balance, suggesting soft-tissue deposition. Fasting blood and urine biochemistries of calcium and phosphate homeostasis were unaffected by calcium carbonate. Thus, the positive calcium balance produced by calcium carbonate treatment within 3 weeks cautions against its use as a phosphate binder in patients with stage 3 or 4 CKD, if these findings can be extrapolated to long-term therapy.

  7. Synthesis and characterization of cadmium-calcium hydroxyapatite solid solutions (United States)

    Zhao, Xin; Zhu, Yi-nian; Dai, Liu-qin


    A series of cadmium-calcium hydroxyapatite solid solutions was prepared by an aqueous precipitation method. By various means, the characterizations confirmed the formation of continuous solid solutions over all ranges of Cd/(Cd+Ca) atomic ratio. In the results, both lattice parameters a and c display slight deviations from Vegard's rule when the Cd/(Cd+Ca) atomic ratio is greater than 0.6. The particles change from smaller acicular to larger hexagonal columnar crystals as the Cd/(Cd+Ca) atomic ratio increases from 0-0.60 to 0.60-1.00. The area of the phosphate peak for symmetric P-O stretching decreases with the increase in Cd/(Cd+Ca) atomic ratio, and the peak disappears when the Cd/(Cd+Ca) atomic ratio is greater than 0.6; the two phosphate peaks of P-O stretching gradually merge together for the Cd/(Cd+Ca) atomic ratio near 0.60. These variations can be explained by a slight tendency of larger Cd ions to occupy M(2) sites and smaller Ca ions to prefer M(1) sites in the structure.

  8. The influence of environmental calcium concentrations on calcium flux, compensatory drinking and epithelial calcium channel expression in a freshwater cartilaginous fish. (United States)

    Allen, Peter J; Weihrauch, Dirk; Grandmaison, Vanessa; Dasiewicz, Patricia; Peake, Stephan J; Anderson, W Gary


    Calcium metabolism and mRNA levels of the epithelial calcium channel (ECaC) were examined in a freshwater cartilaginous fish, the lake sturgeon Acipenser fulvescens. Lake sturgeon were acclimated for ≥2 weeks to 0.1 (low), 0.4 (normal) or 3.3 (high) mmol l(-1) environmental calcium. Whole-body calcium flux was examined using (45)Ca as a radioactive marker. Net calcium flux was inward in all treatment groups; however, calcium influx was greatest in the low calcium environment and lowest in the high calcium environment, whereas efflux had the opposite relationship. A significant difference in the concentration of (45)Ca in the gastrointestinal tract (GIT) of fish in the low calcium environment led to the examination of drinking rate and calcium flux across the anterior-middle (mid) intestine. Drinking rate was not different between treatments; however, calcium influx across the mid-intestine in the low calcium treatment was significantly greater than that in both the normal and high calcium treatments. The lake sturgeon ECaC was 2831 bp in length, with a predicted protein sequence of 683 amino acids that shared a 66% identity with the closest sequenced ECaCs from the vertebrate phyla. ECaC mRNA levels were examined in the gills, kidney, pyloric caeca, mid-intestine and spiral intestine. Expression levels were highest in the gills, then the kidneys, and were orders of magnitude lower in the GIT. Contrary to existing models for calcium uptake in the teleost gill, ECaC expression was greatest in high calcium conditions and kidney ECaC expression was lowest in low calcium conditions, suggesting that cellular transport mechanisms for calcium may be distinctly different in these freshwater cartilaginous fishes.

  9. Acute effects of calcium carbonate, calcium citrate and potassium citrate on markers of calcium and bone metabolism in young women. (United States)

    Karp, Heini J; Ketola, Maarit E; Lamberg-Allardt, Christel J E


    Both K and Ca supplementation may have beneficial effects on bone through separate mechanisms. K in the form of citrate or bicarbonate affects bone by neutralising the acid load caused by a high protein intake or a low intake of alkalising foods, i.e. fruits and vegetables. Ca is known to decrease serum parathyroid hormone (S-PTH) concentration and bone resorption. We compared the effects of calcium carbonate, calcium citrate and potassium citrate on markers of Ca and bone metabolism in young women. Twelve healthy women aged 22-30 years were randomised into four controlled 24 h study sessions, each subject serving as her own control. At the beginning of each session, subjects received a single dose of calcium carbonate, calcium citrate, potassium citrate or a placebo in randomised order. The diet during each session was identical, containing 300 mg Ca. Both the calcium carbonate and calcium citrate supplement contained 1000 mg Ca; the potassium citrate supplement contained 2250 mg K. Markers of Ca and bone metabolism were followed. Potassium citrate decreased the bone resorption marker (N-terminal telopeptide of type I collagen) and increased Ca retention relative to the control session. Both Ca supplements decreased S-PTH concentration. Ca supplements also decreased bone resorption relative to the control session, but this was significant only for calcium carbonate. No differences in bone formation marker (bone-specific alkaline phosphatase) were seen among the study sessions. The results suggest that potassium citrate has a positive effect on the resorption marker despite low Ca intake. Both Ca supplements were absorbed well and decreased S-PTH efficiently.

  10. Protective effect of reduced glutathione C60 derivative against hydrogen peroxide-induced apoptosis in HEK 293T cells. (United States)

    Huang, Jin; Zhou, Chi; He, Jun; Hu, Zheng; Guan, Wen-Chao; Liu, Sheng-Hong


    Hydrogen peroxide (H2O2) and free radicals cause oxidative stress, which induces cellular injuries, metabolic dysfunction, and even cell death in various clinical abnormalities. Fullerene (C60) is critical for scavenging oxygen free radicals originated from cell metabolism, and reduced glutathione (GSH) is another important endogenous antioxidant. In this study, a novel water-soluble reduced glutathione fullerene derivative (C60-GSH) was successfully synthesized, and its beneficial roles in protecting against H2O2-induced oxidative stress and apoptosis in cultured HEK 293T cells were investigated. Fourier Transform infrared spectroscopy and (1)H nuclear magnetic resonance were used to confirm the chemical structure of C60-GSH. Our results demonstrated that C60-GSH prevented the reactive oxygen species (ROS)-mediated cell damage. Additionally, C60-GSH pretreatment significantly attenuated H2O2-induced superoxide dismutase (SOD) consumption and malondialdehyde (MDA) elevation. Furthermore, C60-GSH inhibited intracellular calcium mobilization, and subsequent cell apoptosis via bcl-2/bax-caspase-3 signaling pathway induced by H2O2 stimulation in HEK 293T cells. Importantly, these protective effects of C60-GSH were superior to those of GSH. In conclusion, these results suggested that C60-GSH has potential to protect against H2O2-induced cell apoptosis by scavenging free radicals and maintaining intracellular calcium homeostasis without evident toxicity.

  11. Nitrite-cured color and phosphate-mediated water binding of pork muscle proteins as affected by calcium in the curing solution. (United States)

    Zhao, Jing; Xiong, Youling L


    Calcium is a mineral naturally present in water and may be included into meat products during processing thereby influencing meat quality. Phosphates improve myofibril swelling and meat water-holding capacity (WHC) but can be sensitive to calcium precipitation. In this study, pork shoulder meat was used to investigate the impact of calcium at 0, 250, and 500 ppm and phosphate type [sodium pyrophosphate (PP), tripolyphosphate (TPP), and hexametaphopshate (HMP)] at 10 mM on nitrite-cured protein extract color at various pH levels (5.5, 6.0, and 6.5) and crude myofibril WHC at pH 6.0. Neither calcium nor phosphates present in the curing brines significantly affected the cured color. Increasing the pH tended to promote the formation of metmyoglobin instead of nitrosylmyoglobin. The ability of PP to enhance myofibril WHC was hampered (P water binding by myofibrils. The depressed muscle fiber swelling responding to added calcium as evidenced by phase contrast microscopy substantiated, to a certain extent, the deleterious effect of calcium, suggesting that hardness of curing water can significantly affect the quality of cured meat products. Although not affecting nitrite-cured color, calcium hampers the efficacy of phosphates to promote water binding by muscle proteins, underscoring the importance of water quality for brine-enhanced meat products. © 2012 Institute of Food Technologists®

  12. A high stability optical frequency reference based on thermal calcium atoms (United States)


    simple, compact optical frequency standard based upon thennal calcium atoms. Using a Ramsey- Borde specu·ometer we excite features with linewidths &#60 5kHz...Optical Frequency (kHz) Figure 2: Ramsey- Borde fringes , shown here with both recoil components. Fringe width is &#60 5kHz (FWHM). tlli.s theoretical value...send ~ 2 m W of the light to a fom-beam Ramsey- Borde spectrometer that excites the atoms in a thermal beam [3]. Atoms emerge from an aperture in theCa

  13. 60 years: sleek and stylish

    CERN Multimedia

    Anaïs Schaeffer


    As you are aware, CERN will be celebrating its 60th birthday in 2014. To mark the event, next year will be filled with exciting events... of which there will be a taster in the next issue of the Bulletin.   In the meantime, we are pleased to present the official logo for this important anniversary: created by the Graphic Design Service team, it elegantly combines the curves of the numbers 6 and 0 to mirror the shape of our accelerator chain, and in doing so pays homage to the technological prowess of CERN’s installations. The overlap of the 6 and the 0 also symbolises collaboration between countries, professions and people, which is one of the Organization’s fundamental values. The slightly tilted perspective of the logo suggests the geographical layout of CERN’s facilities as well as the dynamism of a forward-looking Laboratory. There’s an obvious nod to the CERN logo, but the new logo differs in the way it evokes a more festive spirit: formed of a loo...

  14. PTHrP regulation and calcium balance in sea bream (Sparus auratus L.) under calcium constraint

    NARCIS (Netherlands)

    Abbink, W.; Bevelander, G.S.; Hang, X.; Lu, W.; Guerreiro, P.M.; Spanings, T.; Canario, A.V.; Flik, G.


    Juvenile gilthead sea bream were exposed to diluted seawater (2.5 per thousand salinity; DSW) for 3 h or, in a second experiment, acclimated to DSW and fed a control or calcium-deficient diet for 30 days. Branchial Ca(2+) influx, drinking rate and plasma calcium levels were assessed. Sea bream

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

    DEFF Research Database (Denmark)

    Hounsgaard, J; Kiehn, O


    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......+ spikes and Ca2+ plateaux are present in dendrites of spinal motoneurones of the turtle....

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

    NARCIS (Netherlands)

    Schaafsma, A.; Beelen, G.M.


    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

  17. Calcium response to vitamin D supplementation

    Directory of Open Access Journals (Sweden)

    Francisco R. Spivacow


    Full Text Available Several studies show the importance of serum vitamin D sufficient levels to prevent multiple chronic diseases. However, vitamin D supplementation and its effects on urine calcium excretion remain controversial. The objective of this prospective and interventional study was to evaluate urine calcium excretion in women with normal calciuria or hypercalciuria, once serum vitamin D sufficiency was achieved. We studied 63 women with idiopathic hypercalciuria, (9 with renal lithiasis and 50 normocalciuric women. Both groups had serum vitamin D levels low (deficiency or insufficiency. Baseline urine calcium excretion was measured before being supplemented with vitamin D2 or D3 weekly or vitamin D3 100.000 IU monthly. Once serum vitamin D levels were corrected achieving at least 30 ng/ml, a second urine calcium excretion was obtained. Although in the whole sample we did not observe significant changes in urine calcium excretion according to the way of supplementation, some of those with weekly supplementation had significant higher urine calcium excretion, 19% (n = 12 of hypercalciuric women and 12% (n = 6 of the normocalciuric group. Monthly doses, also showed higher urine calcium excretion in 40% of hypercalciuric women (n = 4/10 and in 44% (n = 4/9 of the renal lithiasis hypercalciuric patients. In conclusion, different ways of vitamin D supplementation and adequate serum levels are safe in most patients, although it should be taken into account a subgroup, mainly with monthly loading doses, that could increase the calciuria significantly eventually rising renal lithiasis risk or bone mass loss, if genetically predisposed.


    Directory of Open Access Journals (Sweden)



    Full Text Available

    The osmotic dehydration kinetics of guavas in maltose solutions at 40 and 60ºBrix, with addition of 0, 0.6 and 1.2% of calcium lactate was studied in this paper and the final product quality was evaluated. The experiments were carried out up to 60 hours and samples were taken for analysis at different times to evaluate guavas weight reduction, water loss and sugar gain and to characterize the product according to its texture and color. After 24 hours of process the mass transfer of water and sugar between the osmotic solution and the fruit was negligible, showing that process equilibrium was reached. The increase of sugar concentration in the osmotic solution showed strong influence on the dehydration process, increasing the water loss and reducing sugar gain. The presence of calcium ions in the osmotic solution also influenced the kinetics of mass transfer and showed a strong influence on fruit texture. Higher values of stress and strain at failure were obtained when calcium lactate was employed. The effect of the different osmotic treatments on the color parameters was also investigated and significant changes were observed in the values of chroma C* and hue H* due to sugar concentration and calcium addition.

    KEYWORDS: Osmotic dehydration; kinetics; guava; maltose; calcium lactate.

  19. Calcium carbonate polyamorphism and its role in biomineralization: how many amorphous calcium carbonates are there? (United States)

    Cartwright, Julyan H E; Checa, Antonio G; Gale, Julian D; Gebauer, Denis; Sainz-Díaz, C Ignacio


    Although the polymorphism of calcium carbonate is well known, and its polymorphs--calcite, aragonite, and vaterite--have been highly studied in the context of biomineralization, polyamorphism is a much more recently discovered phenomenon, and the existence of more than one amorphous phase of calcium carbonate in biominerals has only very recently been understood. Here we summarize what is known about polyamorphism in calcium carbonate as well as what is understood about the role of amorphous calcium carbonate in biominerals. We show that consideration of the amorphous forms of calcium carbonate within the physical notion of polyamorphism leads to new insights when it comes to the mechanisms by which polymorphic structures can evolve in the first place. This not only has implications for our understanding of biomineralization, but also of the means by which crystallization may be controlled in medical, pharmaceutical, and industrial contexts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Bond strength of a calcium silicate-based sealer tested in bulk or with different main core materials. (United States)

    Nagas, Emre; Cehreli, Zafer; Uyanik, Mehmet Ozgur; Durmaz, Veli


    The aim of this study was to evaluate the influence of a calcium silicate-based sealer (iRoot SP), with or without a core material, on bond strength to radicular dentin, in comparison with various contemporary root filling systems. Root canals of freshly extracted single-rooted teeth (n = 60) were instrumented using rotary instruments. The roots were randomly assigned to one of the following experimental groups: (1) a calcium silicate-based sealer without a core material (bulk-fill); (2) a calcium silicate-based sealer + gutta-percha; (3) a calcium silicate-based sealer + Resilon; (4) a methacrylate resin-based sealer (RealSeal SE) + Resilon; (5) an epoxy resin-based sealer (AH Plus) + gutta-percha, and (6) a mineral trioxide aggregate-based endodontic sealer (MTA Fillapex) + gutta-percha. Four 1-mm-thick sections were obtained from the coronal aspect of each root (n = 40 slices/group). Push-out bond strength testing was performed at a cross-head speed of 1 mm/min, and the bond strength data were analyzed statistically by one-way analysis of variance and Tukey tests (p core filling materials. When the calcium silicate-based sealer was placed in bulk, its dislocation resistance was similar to that of commonly used sealer + core root filling systems. Thus, the concept of using a calcium silicate-based sealer in bulk can be more easily advocated in clinical practice.

  1. Biocompatibility and setting time of CPM-MTA and white Portland cement clinker with or without calcium sulfate

    Directory of Open Access Journals (Sweden)

    Clovis Monteiro BRAMANTE


    Full Text Available Objective To evaluate the biocompatibility and the setting time of Portland cement clinker with or without 2% or 5% calcium sulfate and MTA-CPM. Material and Methods Twenty-four mice (Rattus norvegicus received subcutaneously polyethylene tubes filled with Portland cement clinker with or without 2% or 5% calcium sulfate and MTA. After 15, 30 and 60 days of implantation, the animals were killed and specimens were prepared for microscopic analysis. For evaluation of the setting time, each material was analyzed using Gilmore needles weighing 113.5 g and 456.5 g, according to the ASTM specification Number C266-08 guideline. Data were analyzed by ANOVA and Tukey's test for setting time and Kruskal-Wallis and Dunn test for biocompatibility at 5% significance level. Results Histologic observation showed no statistically significant difference of biocompatibility (p>0.05 among the materials in the subcutaneous tissues. For the setting time, clinker without calcium sulfate showed the shortest initial and final setting times (6.18 s/21.48 s, followed by clinker with 2% calcium sulfate (9.22 s/25.33 s, clinker with 5% calcium sulfate (10.06 s/42.46 s and MTA (15.01 s/42.46 s. Conclusions All the tested materials showed biocompatibility and the calcium sulfate absence shortened the initial and final setting times of the white Portland cement clinker.

  2. Can calcium ionophore "use" in patients with diminished ovarian reserve increase fertilization and pregnancy rates? A randomized, controlled study. (United States)

    Caglar Aytac, Pinar; Kilicdag, Esra Bulgan; Haydardedeoglu, Bulent; Simsek, Erhan; Cok, Tayfun; Parlakgumus, Huriye Ayse


    To determine whether calcium ionophore solution can improve the fertilization rate in patients with diminished ovarian reserve whose partners have normal sperm parameters. Between January 2014 and August 2014, patients with diminished ovarian reserve were randomized to make artificial oocyte activation with calcium ionophore solution. University hospital. A total of 296 patients who had diminished ovarian reserve and partners with normal sperm parameters were included in the study. Metaphase 2 oocytes were treated with calcium ionophore solution (GM508 Cult-Active) for 15 minutes just after intracytoplasmic sperm injection. Fertilization rate, implantation rate, clinical pregnancy rate, ongoing pregnancy rate. Fertilization, implantation, pregnancy, and ongoing pregnancy rates for the calcium ionophore and control groups were 60.7% and 55.4%, 12.8% and 10.7%, 21% and 12.8%, and 10.9% and 6.1%, respectively. This is the first prospective, randomized, controlled study to analyze the effect of calcium ionophore solution on fertilization rate in patients with diminished ovarian reserve. We did not observe any differences in fertilization, clinical pregnancy, or ongoing pregnancy rates between the groups. We propose that fertilization ratios could not be increased by artificial oocyte activation via application of calcium ionophore solution in patients with diminished ovarian reserve. NCT02045914. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.


    African Journals Online (AJOL)

    cation exchange capacity (CECe) values of the soils were generally low: organic carbon content and Bray-1. Pvalues of the surface ... sum of exchangeable Ca, Mg, Na, K, Al and H. The difierence between CECg and CECe was calculated to represent the ..... The effect of soil Solution aluminum and calcium in root growth.

  4. Calcium-Induced calcium release during action potential firing in developing inner hair cells. (United States)

    Iosub, Radu; Avitabile, Daniele; Grant, Lisa; Tsaneva-Atanasova, Krasimira; Kennedy, Helen J


    In the mature auditory system, inner hair cells (IHCs) convert sound-induced vibrations into electrical signals that are relayed to the central nervous system via auditory afferents. Before the cochlea can respond to normal sound levels, developing IHCs fire calcium-based action potentials that disappear close to the onset of hearing. Action potential firing triggers transmitter release from the immature IHC that in turn generates experience-independent firing in auditory neurons. These early signaling events are thought to be essential for the organization and development of the auditory system and hair cells. A critical component of the action potential is the rise in intracellular calcium that activates both small conductance potassium channels essential during membrane repolarization, and triggers transmitter release from the cell. Whether this calcium signal is generated by calcium influx or requires calcium-induced calcium release (CICR) is not yet known. IHCs can generate CICR, but to date its physiological role has remained unclear. Here, we used high and low concentrations of ryanodine to block or enhance CICR to determine whether calcium release from intracellular stores affected action potential waveform, interspike interval, or changes in membrane capacitance during development of mouse IHCs. Blocking CICR resulted in mixed action potential waveforms with both brief and prolonged oscillations in membrane potential and intracellular calcium. This mixed behavior is captured well by our mathematical model of IHC electrical activity. We perform two-parameter bifurcation analysis of the model that predicts the dependence of IHCs firing patterns on the level of activation of two parameters, the SK2 channels activation and CICR rate. Our data show that CICR forms an important component of the calcium signal that shapes action potentials and regulates firing patterns, but is not involved directly in triggering exocytosis. These data provide important insights

  5. Store-operated calcium entry and increased endothelial cell permeability. (United States)

    Norwood, N; Moore, T M; Dean, D A; Bhattacharjee, R; Li, M; Stevens, T


    We hypothesized that myosin light chain kinase (MLCK) links calcium release to activation of store-operated calcium entry, which is important for control of the endothelial cell barrier. Acute inhibition of MLCK caused calcium release from inositol trisphosphate-sensitive calcium stores and prevented subsequent activation of store-operated calcium entry by thapsigargin, suggesting that MLCK serves as an important mechanism linking store depletion to activation of membrane calcium channels. Moreover, in voltage-clamped single rat pulmonary artery endothelial cells, thapsigargin activated an inward calcium current that was abolished by MLCK inhibition. F-actin disruption activated a calcium current, and F-actin stabilization eliminated the thapsigargin-induced current. Thapsigargin increased endothelial cell permeability in the presence, but not in the absence, of extracellular calcium, indicating the importance of calcium entry in decreasing barrier function. Although MLCK inhibition prevented thapsigargin from stimulating calcium entry, it did not prevent thapsigargin from increasing permeability. Rather, inhibition of MLCK activity increased permeability that was especially prominent in low extracellular calcium. In conclusion, MLCK links store depletion to activation of a store-operated calcium entry channel. However, inhibition of calcium entry by MLCK is not sufficient to prevent thapsigargin from increasing endothelial cell permeability.

  6. The spatial pattern of atrial cardiomyocyte calcium signalling modulates contraction. (United States)

    Mackenzie, Lauren; Roderick, H Llewelyn; Berridge, Michael J; Conway, Stuart J; Bootman, Martin D


    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 (approximately 2 microm) intervals throughout atrial myocytes, the subsarcolemmal calcium signal did not spread in a fully regenerative manner through the interior of a cell. Rather, there was a diminishing centripetal propagation of calcium. The lack of regeneration was due to mitochondria and SERCA pumps preventing the inward movement of calcium. Inhibiting these calcium buffering mechanisms allowed the globalisation of action potential-evoked responses. In addition, physiological positive inotropic agents, such as endothelin-1 and beta-adrenergic agonists, as well as enhanced calcium current, calcium store loading and inositol 1,4,5-trisphosphate infusion also led to regenerative global responses. The consequence of globalising calcium signals was a significant increase in cellular contraction. These data indicate how calcium signals and their consequences are determined by the interplay of multiple subcellular calcium management systems.

  7. Calcium Aluminate Cement Hydration Model

    Directory of Open Access Journals (Sweden)

    Matusinović, T.


    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

  8. Phase transitions in biogenic amorphous calcium carbonate (United States)

    Gong, Yutao

    Geological calcium carbonate exists in both crystalline phases and amorphous phases. Compared with crystalline calcium carbonate, such as calcite, aragonite and vaterite, the amorphous calcium carbonate (ACC) is unstable. Unlike geological calcium carbonate crystals, crystalline sea urchin spicules (99.9 wt % calcium carbonate and 0.1 wt % proteins) do not present facets. To explain this property, crystal formation via amorphous precursors was proposed in theory. And previous research reported experimental evidence of ACC on the surface of forming sea urchin spicules. By using X-ray absorption near-edge structure (XANES) spectroscopy and photoelectron emission microscopy (PEEM), we studied cross-sections of fresh sea urchin spicules at different stages (36h, 48h and 72h after fertilization) and observed the transition sequence of three mineral phases: hydrated ACC → dehydrated ACC → biogenic calcite. In addition, we unexpectedly found hydrated ACC nanoparticles that are surrounded by biogenic calcite. This observation indicates the dehydration from hydrated ACC to dehydrated ACC is inhibited, resulting in stabilization of hydrated ACC nanoparticles. We thought that the dehydration was inhibited by protein matrix components occluded within the biomineral, and we designed an in vitro assay to test the hypothesis. By utilizing XANES-PEEM, we found that SM50, the most abundant occluded matrix protein in sea urchin spicules, has the function to stabilize hydrated ACC in vitro.

  9. Do Calcium Supplements Predispose to Urolithiasis? (United States)

    Kozyrakis, Diomidis; Paridis, Dionysios; Karatzas, Anastasios; Soukias, Georgios; Dailiana, Zoi


    The purpose of this study was to investigate the role of calcium supplements, with or without vitamin D, in urinary stone formation in healthy population and in osteoporotic patients as well. Moreover, this review aims to clarify whether or not, and above which dose, they are associated with the risk of lithiasis. A research in Medline, Embase, and Scopus databases up to September 2015 was conducted using the following keywords: calcium, supplements, vitamin D, complications, lithiasis, and urinary stone. All types of studies were taken into account (cohort studies, reviews, meta-analyses), and in case they fulfilled the inclusion criteria, they were included in our review. The analysis of the data showed that calcium supplements, probably in association with anti osteoporotic treatment, do not create a predisposition towards lithiasis formation among women suffering from osteoporosis, neither among non-osteoporotic older men. In healthy postmenopausal as well as younger women, the supplements might increase susceptibility to urinary stone formation in long-term basis. The consumption of calcium supplements with the meals could play a protective role in women and younger males. There is certain evidence that supplements containing citrate may be more beneficial over the rest of calcium supplements, particularly when consumed during the meal. Osteoporotic women and healthy men are not at risk of stone formation. On the contrary, healthy women should be aware of the potential risk of developing urinary lithiasis in long-term basis.

  10. Voltage-Gated Calcium Channels in Nociception (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.

  11. Calcium's Role in Mechanotransduction during Muscle Development

    Directory of Open Access Journals (Sweden)

    Tatiana Benavides Damm


    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.

  12. Influence of calcium and magnesium salts on acid soil chemistry and calcium nutrition of apple

    Energy Technology Data Exchange (ETDEWEB)

    Pavan, M.A.; Bingham, F.T.; Peryea, F.J.

    Field experiments were conducted in two Brazilian orchards to examine the effects of soil applications of calcitic lime (Ca-lime), phosphogypsum, CaCl/sub 2/, and magnesite (Mg-lime) on soil chemistry and Ca nutrition of apple (Malus domestica Borkh, cv. Gala/MM 106). One orchard was on a low Ca, high Al Inceptisol; the second orchard was on a low Ca, low Al Oxisol. The resulting soil chemical changes were strongly influenced by the initial soil chemistry and the composition of the soil amendments. The effects of Ca-lime, added at a rate calculated to neutralize the topsoil exchange acidity, were restricted primarily to the upper 20 cm of the soil, where it increased pH, increased total dissolved and exchangeable Ca, eliminated dissolved Al, and reduced exchangeable Al. Phosphogypsum, added at Ca rates equivalent to the Ca-lime treatment, slightly reduced soil pH in the Inceptisol and slightly increased soil pH in the Oxisol. Phosphogypsum did not appreciably affect dissolved Al in the topsoil; however, it did reduce exchangeable Al but to a lesser degree than did Ca-lime or Mg-lime. Phosphogypsum increased exchangeable Ca and decreased exchangeable Al in the subsoil to a depth of 40 to 60 cm. Calcium chloride, added at Ca rates equivalent to the Ca-lime treatment, produced dissolved and exchangeable Ca increases similar to the phosphogypsum treatment; however, soluble and exchangeable Al were increased and pH slightly decreased through out the soil profiles.

  13. Calcium acetate or calcium carbonate for hyperphosphatemia of hemodialysis patients: a meta-analysis. (United States)

    Wang, Yong; Xie, Guoqiang; Huang, Yuanhang; Zhang, Han; Yang, Bo; Mao, Zhiguo


    High levels of serum phosphorus both at baseline and during follow-up are associated with increased mortality in dialysis patients, and administration of phosphate binders was independently associated with improved survival among hemodialysis population. Calcium-based phosphate binders are the most commonly used phosphate binders in developing countries for their relatively low costs. To compare the efficacy and safety between calcium carbonate and calcium acetate in the treatment of hyperphosphatemia in hemodialysis patients. PubMed, EMBASE, Cochrane Library, Google scholar and Chinese databases (Wanfang, Weipu, National Knowledge Infrastructure of China) were searched for relevant studies published before March 2014. Reference lists of nephrology textbooks and review articles were checked. A meta-analysis of randomized controlled trials (RCTs) and quasi-RCTs that assessed the effects and adverse events of calcium acetate and calcium carbonate in adult patients with MHD was performed using Review Manager 5.0. A total of ten studies (625 participants) were included in this meta-analysis. There was insufficient data in all-cause mortality and cardiovascular events for meta-analysis. Compared with calcium carbonate group, the serum phosphorus was significantly lower in calcium acetate group after4 weeks' administration (MD -0.15 mmol/L, 95% CI -0.28 to -0.01) and after 8 weeks' administration (MD -0.25 mmol/L, 95% CI -0.40 to -0.11). There was no difference in serum calcium levels or the incidence of hypercalcemia between two groups at 4 weeks and 8 weeks. No statistical difference was found in parathyroid hormone (PTH) levels or serum calcium by phosphorus (Ca x P) product. There was significantly higher risk of intolerance with calcium acetate treatment (RR 3.46, 95% CI 1.48 to 8.26). For hyperphosphatemia treatment, calcium acetate showed better efficacy and with a higher incidence of intolerance compared with calcium carbonate. There are insufficient data to

  14. Effect of potassium and calcium loading on healthy subjects under hypokinesia and physical exercise with fluid and salt supplements (United States)

    Zorbas, Yan G.; Naexu, Konstantin A.; Federenko, Youri F.


    The objective of this investigation was to determine the acute responses to the electrolyte challenges under hypokinesia and physical exercise (PE) of different intensities with fluid and salt supplementation (FSS). The studies were performed on 12 physically healthy male volunteers aged 19-24 years under 364 days of hypokinesia (decreased number of steps per day) with a set of PE with FSS. The volunteers were divided into two equal groups. The first group was subjected to a set of intensive PE and the second group was submitted to a set of moderate PE. Both groups of subjects consumed daily water and salt supplements that aimed to increase the body hydration level. For simulation of the hypokinetic effect all subjects were kept under an average of 3000 steps per day. Functional tests with a potassium chloride (KCl) and calcium lactate (Cal) load were performed during the hypokinetic period of 364 days and the 60-day prehypokinetic period that served as control, while both groups of subjects consumed daily calcium and potassium supplements. The concentration of electrolyte and hormone levels in the blood and their excretion rate in urine were determined. Renal excretion of calcium and potassium and the blood concentration thereof increased markedly in both groups of subjects. With the potassium chloride load tests the increased potassium excretion was accompanied by higher aldosterone and insulin blood levels, and with the calcium lactate load tests the increased calcium excretion was accompanied by a decreased parathyroid content in the blood. FSS and PE, regardless of intensity, failed to attenuate calcium and potassium losses. Additional intake of KCl and Cal also failed to normalize potassium and calcium abnormalities. It was concluded that during the KCl and Cal loading tests, the increased losses of potassium and calcium in the hypokinetic subjects were due to the inability of their bodies to retain these electrolytes, and that electrolyte abnormalities could

  15. Prevention and Treatment of Vitamin D and Calcium Deficiency in Children and Adolescents: Indian Academy of Pediatrics (IAP) Guidelines. (United States)

    Khadilkar, Anuradha; Khadilkar, Vaman; Chinnappa, Jagdish; Rathi, Narendra; Khadgawat, Rajesh; Balasubramanian, S; Parekh, Bakul; Jog, Pramod


    Vitamin D deficiency (VDD) is being increasingly reported from India from all age-groups. Reports suggest that VDD affects all age groups, from neonates to adolescents. Further, habitually low calcium intakes are also reported in Indian children. Given the multiple guidelines, peculiarities of Indian circumstances, changing lifestyles, and lack of fortification, the Indian Academy of Pediatrics (IAP) felt the need for a Practice Guideline for Pediatricians for the prevention and treatment of vitamin D and calcium deficiency in children and adolescents. The 'Guideline for Vitamin D and Calcium in Children' committee was formed by the IAP in September 2016. A consultative committee meeting was held in November 2016 in Mumbai. Evidence from Indian and international studies and other previous published recommendations, which were pertinent to the Indian circumstances, were collated for the preparation of these guidelines. To present a practice guideline for pediatricians for the prevention and treatment of deficiency of vitamin D and calcium in the Indian context. For the prevention of rickets in premature infants, 400 IU of vitamin D and 150-220 mg/kg of calcium, and in neonates, 400 IU of vitamin D and 200 mg of calcium are recommended daily. For prevention of rickets and hypocalcemia in infants (after neonatal period) upto 1 year of age, and from 1-18 years, 400 IU and 600 IU vitamin D/day and 250-500 mg/day and 600-800 mg/day of calcium, respectively, are recommended. For treatment of rickets in premature neonates, infants upto 1 year and from 1-18 years, 1000 IU, 2000 IU and 3000-6000 IU of vitamin D daily, respectively, and elemental calcium of 70-80 mg/kg/day in premature neonates and 500-800 mg daily for all children over that age are recommended. Larger doses of vitamin D may be given from 3 months to 18 years of age as 60,000 IU/week for 6 weeks.

  16. 40 CFR 60.471 - Definitions. (United States)


    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Definitions. 60.471 Section 60.471... Manufacture § 60.471 Definitions. As used in this subpart, all terms not defined herein shall have the meaning.... Electrostatic precipitator (ESP) means an air pollution control device in which solid or liquid particulates in...

  17. 40 CFR 60.391 - Definitions. (United States)


    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Definitions. 60.391 Section 60.391... Coating Operations § 60.391 Definitions. (a) All terms used in this subpart that are not defined below.... Electrostatic spray application means a spray application method that uses an electrical potential to increase...

  18. 21 CFR 558.60 - Arsanilate sodium. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Arsanilate sodium. 558.60 Section 558.60 Food and... in Animal Feeds § 558.60 Arsanilate sodium. (a) Appprovals. Type A medicated articles: 20, 50, or 100...) Arsanilate sodium may be used in accordance with the provisions of this section in the combinations provided...

  19. 14 CFR 60.11 - FSTD use. (United States)


    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false FSTD use. 60.11 Section 60.11 Aeronautics... SIMULATION TRAINING DEVICE INITIAL AND CONTINUING QUALIFICATION AND USE § 60.11 FSTD use. No person may use or allow the use of or offer the use of an FSTD for flight crewmember training or evaluation or for...

  20. 15 CFR 60.1 - Public information. (United States)


    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Public information. 60.1 Section 60.1 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade BUREAU OF THE CENSUS, DEPARTMENT OF COMMERCE PUBLIC INFORMATION § 60.1 Public information. The rules and procedures regarding...

  1. 46 CFR 151.50-60 - Benzene. (United States)


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Benzene. 151.50-60 Section 151.50-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-60 Benzene. The person in charge of a...

  2. 21 CFR 556.60 - Arsenic. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Arsenic. 556.60 Section 556.60 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND... New Animal Drugs § 556.60 Arsenic. Tolerances for total residues of combined arsenic (calculated as As...

  3. 10 CFR 60.65 - Representation. (United States)


    ... 10 Energy 2 2010-01-01 2010-01-01 false Representation. 60.65 Section 60.65 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN GEOLOGIC REPOSITORIES Participation by State Governments and Affected Indian Tribes § 60.65 Representation. Any person who acts under...

  4. 10 CFR 60.9 - Employee protection. (United States)


    ... occurs because the employee has engaged in protected activities. An employee's engagement in protected... 10 Energy 2 2010-01-01 2010-01-01 false Employee protection. 60.9 Section 60.9 Energy NUCLEAR... Provisions § 60.9 Employee protection. (a) Discrimination by a Commission licensee, an applicant for a...

  5. 40 CFR 791.60 - Review. (United States)


    ... 40 Protection of Environment 31 2010-07-01 2010-07-01 true Review. 791.60 Section 791.60...) DATA REIMBURSEMENT Review § 791.60 Review. (a) The hearing officer's proposed order shall become the... Agency review or the Administrator of his own initiative decides to review the proposed order. (b) The...

  6. 49 CFR 570.60 - Steering system. (United States)


    ... 49 Transportation 6 2010-10-01 2010-10-01 false Steering system. 570.60 Section 570.60... 10,000 Pounds § 570.60 Steering system. (a) System play. Lash or free play in the steering system... excessive lash or free play in the steering system. Table 2. Steering Wheel Free Play Values Steering wheel...

  7. 45 CFR 60.3 - Definitions. (United States)


    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Definitions. 60.3 Section 60.3 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION NATIONAL PRACTITIONER DATA BANK FOR ADVERSE INFORMATION ON PHYSICIANS AND OTHER HEALTH CARE PRACTITIONERS General Provisions § 60.3 Definitions. Act means...

  8. 21 CFR 640.60 - Source Plasma. (United States)


    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Source Plasma. 640.60 Section 640.60 Food and... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be Source Plasma. The product is defined as the fluid portion of human blood...

  9. 10 CFR 60.31 - Construction authorization. (United States)


    ... 10 Energy 2 2010-01-01 2010-01-01 false Construction authorization. 60.31 Section 60.31 Energy... REPOSITORIES Licenses Construction Authorization § 60.31 Construction authorization. Upon review and... authorize construction if it determines: (a) Safety. That there is reasonable assurance that the types and...

  10. 7 CFR 917.60 - Effective time. (United States)


    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 917.60 Section 917.60 Agriculture... CALIFORNIA Order Regulating Handling Miscellaneous Provisions § 917.60 Effective time. The provisions of this part and of any amendment thereto, shall become effective at such time as the Secretary may declare...

  11. 40 CFR 60.8 - Performance tests. (United States)


    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Performance tests. 60.8 Section 60.8... PERFORMANCE FOR NEW STATIONARY SOURCES General Provisions § 60.8 Performance tests. (a) Except as specified in... conduct performance test(s) and furnish the Administrator a written report of the results of such...

  12. 28 CFR 345.60 - Training pay. (United States)


    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Training pay. 345.60 Section 345.60... (FPI) INMATE WORK PROGRAMS Inmate Pay and Benefits § 345.60 Training pay. Inmates directed by the SOI to take a particular type of training in connection with a FPI job are to receive FPI pay if the...

  13. 7 CFR 956.60 - Marketing policy. (United States)


    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Marketing policy. 956.60 Section 956.60 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... VALLEY OF SOUTHEAST WASHINGTON AND NORTHEAST OREGON Regulation § 956.60 Marketing policy. (a) Preparation...

  14. 7 CFR 930.60 - Equity holders. (United States)


    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Equity holders. 930.60 Section 930.60 Agriculture... Regulations § 930.60 Equity holders. (a) Inventory reserve ownership. The inventory reserve shall be the sole responsibility of the handlers who place products into the inventory reserve. A handler's equity in the primary...

  15. 21 CFR 113.60 - Containers. (United States)


    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Containers. 113.60 Section 113.60 Food and Drugs... CONSUMPTION THERMALLY PROCESSED LOW-ACID FOODS PACKAGED IN HERMETICALLY SEALED CONTAINERS Control of Components, Food Product Containers, Closures, and In-Process Materials § 113.60 Containers. (a) Closures...

  16. 40 CFR 60.291 - Definitions. (United States)


    ... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Glass Manufacturing Plants § 60.291... approximate ranges of weight proportions: 60 to 80 percent silicon dioxide, 4 to 10 percent total R2O (e.g... composition of the following ranges of weight proportions: 50 to 60 percent silicon dioxide, 18 to 35 percent...

  17. 21 CFR 21.60 - Policy. (United States)


    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Policy. 21.60 Section 21.60 Food and Drugs FOOD... Exemptions § 21.60 Policy. It is the policy of the Food and Drug Administration that record systems should be exempted from the Privacy Act only to the extent essential to the performance of law enforcement functions...

  18. 42 CFR 441.60 - Continuing care. (United States)


    ... 42 Public Health 4 2010-10-01 2010-10-01 false Continuing care. 441.60 Section 441.60 Public... Periodic Screening, Diagnosis, and Treatment (EPSDT) of Individuals Under Age 21 § 441.60 Continuing care. (a) Continuing care provider. For purposes of this subpart, a continuing care provider means a...

  19. 42 CFR 483.60 - Pharmacy services. (United States)


    ... 42 Public Health 5 2010-10-01 2010-10-01 false Pharmacy services. 483.60 Section 483.60 Public... Care Facilities § 483.60 Pharmacy services. The facility must provide routine and emergency drugs and... the provision of pharmacy services in the facility; (2) Establishes a system of records of receipt and...

  20. 7 CFR 1215.60 - Reports. (United States)


    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Reports. 1215.60 Section 1215.60 Agriculture... CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information Order Reports, Books, and Records § 1215.60 Reports. (a) Each processor marketing popcorn directly to consumers, and each processor...

  1. 7 CFR 1216.60 - Reports. (United States)


    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Reports. 1216.60 Section 1216.60 Agriculture... INFORMATION ORDER Peanut Promotion, Research, and Information Order Reports, Books, and Records § 1216.60 Reports. (a) Each producer and first handler subject to this part shall be required to report to the...

  2. 42 CFR 60.57 - Reports. (United States)


    ... 42 Public Health 1 2010-10-01 2010-10-01 false Reports. 60.57 Section 60.57 Public Health PUBLIC... The School § 60.57 Reports. A school must submit reports to the Secretary at the times and in the manner the Secretary may reasonably prescribe. The school must retain a copy of each report for not less...

  3. 7 CFR 1209.60 - Reports. (United States)


    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Reports. 1209.60 Section 1209.60 Agriculture... CONSUMER INFORMATION ORDER Mushroom Promotion, Research, and Consumer Information Order Reports, Books and Records § 1209.60 Reports. (a) Each producer marketing mushrooms of that person's own production directly...

  4. 7 CFR 1218.60 - Reports. (United States)


    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Reports. 1218.60 Section 1218.60 Agriculture... INFORMATION ORDER Blueberry Promotion, Research, and Information Order Reports, Books, and Records § 1218.60 Reports. (a) Each first handler subject to this subpart may be required to provide to the Council...

  5. 7 CFR 1206.60 - Reports. (United States)


    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Reports. 1206.60 Section 1206.60 Agriculture... INFORMATION Mango Promotion, Research, and Information Order Definitions Reports, Books, and Records § 1206.60 Reports. (a) Each first handler will be required to provide to the Board periodically such information as...

  6. 47 CFR 3.60 - Reports. (United States)


    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Reports. 3.60 Section 3.60 Telecommunication... MARITIME AND MARITIME MOBILE-SATELLITE RADIO SERVICES Reporting Requirements § 3.60 Reports. (a) Initial... authority is required to submit to the FCC a report on additions, modifications or deletions to its list of...

  7. 42 CFR 422.60 - Election process. (United States)


    ... 42 Public Health 3 2010-10-01 2010-10-01 false Election process. 422.60 Section 422.60 Public...) MEDICARE PROGRAM MEDICARE ADVANTAGE PROGRAM Eligibility, Election, and Enrollment § 422.60 Election process... plan, and in which the MA organization arranges for the employer to process elections for Medicare...

  8. 27 CFR 27.60 - Beer. (United States)


    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Beer. 27.60 Section 27.60... TREASURY LIQUORS IMPORTATION OF DISTILLED SPIRITS, WINES, AND BEER General Requirements Marking and Labeling of Wines and Beer § 27.60 Beer. All imported beer is required to be released from customs custody...

  9. 38 CFR 60.1 - Purpose. (United States)


    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Purpose. 60.1 Section 60.1 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) FISHER HOUSES AND OTHER TEMPORARY LODGING § 60.1 Purpose. This part sets forth requirements regarding the use of...

  10. 10 CFR 60.142 - Design testing. (United States)


    ... 10 Energy 2 2010-01-01 2010-01-01 false Design testing. 60.142 Section 60.142 Energy NUCLEAR... Performance Confirmation Program § 60.142 Design testing. (a) During the early or developmental stages of construction, a program for in situ testing of such features as borehole and shaft seals, backfill, and the...

  11. 10 CFR 60.72 - Construction records. (United States)


    ... 10 Energy 2 2010-01-01 2010-01-01 false Construction records. 60.72 Section 60.72 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN GEOLOGIC REPOSITORIES Records, Reports, Tests, and Inspections § 60.72 Construction records. (a) DOE shall maintain records of...

  12. 7 CFR 3560.60 - Design requirements. (United States)


    ... design. All MFH must be residential in character, except as provided for in § 3560.58(b), and must meet... 7 Agriculture 15 2010-01-01 2010-01-01 false Design requirements. 3560.60 Section 3560.60... AGRICULTURE DIRECT MULTI-FAMILY HOUSING LOANS AND GRANTS Direct Loan and Grant Origination § 3560.60 Design...

  13. 46 CFR 46.10-60 - Control. (United States)


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Control. 46.10-60 Section 46.10-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES SUBDIVISION LOAD LINES FOR PASSENGER VESSELS Administration § 46.10-60 Control. (a) The District Director of Customs or the Coast Guard District Commander may...

  14. 46 CFR 42.07-60 - Control. (United States)


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Control. 42.07-60 Section 42.07-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Control, Enforcement, and Rights of Appeal § 42.07-60 Control. (a) The District Director of Customs or the Coast Guard...

  15. 40 CFR 60.4155 - Banking. (United States)


    ... Generating Units Hg Allowance Tracking System § 60.4155 Banking. (a) Hg allowances may be banked for future... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Banking. 60.4155 Section 60.4155 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF...

  16. 14 CFR 34.60 - Introduction. (United States)


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Introduction. 34.60 Section 34.60 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT FUEL VENTING AND... Gaseous Emissions (Aircraft and Aircraft Gas Turbine Engines) § 34.60 Introduction. (a) Except as provided...

  17. 40 CFR 87.60 - Introduction. (United States)


    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Introduction. 87.60 Section 87.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR... and Aircraft Gas Turbine Engines) § 87.60 Introduction. (a) Except as provided under § 87.5, the...

  18. 7 CFR 3550.60 - Escrow account. (United States)


    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Escrow account. 3550.60 Section 3550.60 Agriculture... DIRECT SINGLE FAMILY HOUSING LOANS AND GRANTS Section 502 Origination § 3550.60 Escrow account. RHS may require that customers deposit into an escrow account amounts necessary to ensure that the account will...

  19. 40 CFR 60.4156 - Account error. (United States)


    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Account error. 60.4156 Section 60.4156... Generating Units Hg Allowance Tracking System § 60.4156 Account error. The Administrator may, at his or her... account. Within 10 business days of making such correction, the Administrator will notify the Hg...

  20. 21 CFR 820.60 - Identification. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Identification. 820.60 Section 820.60 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES QUALITY SYSTEM REGULATION Identification and Traceability § 820.60 Identification. Each manufacturer shall...

  1. 41 CFR 60-999.2 - Display. (United States)


    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Display. 60-999.2 Section 60-999.2 Public Contracts and Property Management Other Provisions Relating to Public Contracts... CONTROL NUMBERS FOR OFCCP INFORMATION COLLECTION REQUIREMENTS § 60-999.2 Display. 41 CFR Part where the...

  2. Encapsulation of lawrencium into C{sub 60} fullerene: Lr@C{sub 60}versus Li@C{sub 60}

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Ambrish Kumar [Department of Physics, University of Lucknow, Lucknow, Uttar Pradesh 226007 (India); Pandey, Sarvesh Kumar [Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India); Misra, Neeraj, E-mail: [Department of Physics, University of Lucknow, Lucknow, Uttar Pradesh 226007 (India)


    The position of Lawrencium (Lr) in the periodic table has been debated several times. It has been noticed that some fundamental properties of Lr differ from the other elements of the actinide series and closely resemble those of alkali metal. To be specific, the first ionization energy of Lr 4.96 eV [Nature 520 (2015) 209] lies within the range assigned to alkali metals. Motivated by this fact, we study Lr@C{sub 60} for the first time and compared its electronic properties with those of Li@C{sub 60}. Using density functional theory and its time dependent version, we explore structures, vibrational infrared spectra, molecular orbital surfaces, density of states and electronic absorption spectra of Lr@C{sub 60} and Li@C{sub 60}. We notice that although Lr resides very close to the centre of C{sub 60} than Li does, the electronic properties of Lr@C{sub 60} closely resemble those of Li@C{sub 60}. For instance, Lr@C{sub 60} is as conducting and polarizable as Li@C{sub 60} due to almost equal frontier orbital energy gap and mean polarizability. This study is expected to provide further evidence where Lr atom mimics the alkali metal. - Highlights: • Lr@C{sub 60} has been studied for the first time. • Lr closely mimics the properties of Li. • Lr@C{sub 60} is as conducting as Li@C{sub 60}. • Lr@C{sub 60} is as polarizable as Li@C{sub 60}.

  3. Toxicity of calcium salts to aqueous microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Lakhina, K.G.; Dolganova, A.V.; Yakobi, L.K.


    This article investigates the toxicity of calcium to aqueous microogranisms by means of a procedure developed by VNII VODGEO (All-Union Scientific-Research Institute of Water Supply, Sewer Systems, Hydrotechnical Facilities, and Engineering Hydrogeology), with certain changes in the preparation of the culture water. Proposes that with this method, calcium toxicity can be determined for groups of microorganisms that are among the most important in biochemical wastewater treatment and self-purification of water bodies (saprophytes, phase I and II nitrifiers). Finds that calcium in the form of the hydroxide and chloride is nontoxic under the following conditions: for protozoa in concentrations up to 2 g/liter, for saprophytic bacteria up to 3 g/liter, for phase I nitrifiers up to 1 g/liter, and for phase II nitrifiers up to 0.1 g/liter.

  4. Magnesium and Calcium in Isolated Cell Nuclei (United States)

    Naora, H.; Naora, H.; Mirsky, A. E.; Allfrey, V. G.


    The calcium and magnesium contents of thymus nuclei have been determined and the nuclear sites of attachment of these two elements have been studied. The nuclei used for these purposes were isolated in non-aqueous media and in sucrose solutions. Non-aqueous nuclei contain 0.024 per cent calcium and 0.115 per cent magnesium. Calcium and magnesium are held at different sites. The greater part of the magnesium is bound to DNA, probably to its phosphate groups. Evidence is presented that the magnesium atoms combined with the phosphate groups of DNA are also attached to mononucleotides. There is reason to believe that those DNA-phosphate groups to which magnesium is bound, less than 1/10th of the total, are metabolically active, while those to which histones are attached seem to be inactive. PMID:13727745

  5. Calcium concentration in the CAPD dialysate

    DEFF Research Database (Denmark)

    Bro, S; Brandi, L; Daugaard, H


    with a reduced dialysate Ca concentration (1.00, 1.25, or 1.35 mmol/L) improved the tolerance to calcium carbonate and/or vitamin D metabolites and reduced the need for Al-containing phosphate binders. When using dialysate Ca 1.25 or 1.35 mmol/L, the initial decrease of plasma Ca and increase of PTH could easily......), doses of calcium carbonate, doses of vitamin D analogs, and requirements of aluminum-containing phosphate binders. STUDY SELECTION: Eleven studies of nonselected CAPD patients, and 13 studies of CAPD patients with hypercalcemia were reviewed. RESULTS: In nonselected CAPD patients, treatment...... for the progression of secondary hyperparathyroidism. When hypercalcemia was present in combination with suppressed PTH levels, a controlled increase of PTH could be obtained with a temporary discontinuation of vitamin D and/or a reduction of calcium carbonate treatment in combination with a dialysate Ca...


    Directory of Open Access Journals (Sweden)

    S A Vladimirov


    Full Text Available Objective: to study the incidence of osteoporosis (OP in patients with calcium pyrophosphate crystal deposition disease (CPCDD. Subjects and methods. Eighty patients with CPCDD were examined. Bone mineral density (BMD of the forearm, lumbar spine, and femoral neck was determined by dual-energy X-ray absorptiometry. Laboratory diagnosis involved determination of the blood levels of C-reactive protein, parathyroid hormone, calcium, magnesium, and phosphorus and the daily urinary excretion of calcium and phosphates. Results. The patients with OP were significantly older than those with normal BMD and osteopenia. Forearm bones were the most common isolated location of OP and osteopenia. Injuries in the history, traumatic fractures, and the intake of diuretics were somewhat more common in the patients diagnosed with OP. The incidence of hyperparathyroidism did not differ significantly in the groups.

  7. In situ preparation of Calcium hydroxide films

    Energy Technology Data Exchange (ETDEWEB)

    Dahle, S.; Voigts, F. [Institut fuer Physik und Physikalische Technologien, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Maus-Friedrichs, W., E-mail: [Institut fuer Physik und Physikalische Technologien, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Clausthaler Zentrum fuer Materialtechnik, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany)


    The in situ preparation of Calcium hydroxide films in an ultra high vacuum (UHV) is constrained by the decomposition of species at the surface and the absence of OH bulk diffusion. Therefore, it is not possible to prepare such films simply by water exposure to a Calcium layer. We present four different approaches for the preparation of Ca(OH){sub 2} films in an UHV. Two of these methods are found to be ineffective for the preparation, the other two are shown to produce Calcium hydroxide films. Both of the two effective procedures make use of H{sub 2} gas exposure. Metastable Induced Electron Spectroscopy, Ultraviolet Photoelectron Spectroscopy, and X-ray Photoelectron Spectroscopy are employed to verify quality and purity of the films.

  8. In situ preparation of calcium carbonate films

    Energy Technology Data Exchange (ETDEWEB)

    Dahle, S. [Clausthaler Zentrum fuer Materialtechnik, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Institut fuer Physik und Physikalische Technologien, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Voigts, F. [Institut fuer Physik und Physikalische Technologien, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Maus-Friedrichs, W., E-mail: [Clausthaler Zentrum fuer Materialtechnik, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Institut fuer Physik und Physikalische Technologien, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany)


    The in situ preparation of calcium carbonate films in an ultra high vacuum (UHV) is inhibited by the decomposition of CO{sub 2} molecules at the surface and the absence of CO{sub 2} bulk diffusion. Therefore, it is not possible to prepare such films simply by CO{sub 2} exposure to a calcium layer. We investigated different approaches for the preparation of CaCO{sub 3} films in an UHV. Among these, only the simultaneous evaporation of Ca atoms in a mixed O{sub 2} and CO{sub 2} atmosphere is able to produce well defined stoichiometric calcium carbonate films. Metastable Induced Electron Spectroscopy, Ultraviolet Photoelectron Spectroscopy and X-ray Photoelectron Spectroscopy are employed to verify quality and purity of the films.

  9. Calcination of calcium carbonate and blend therefor (United States)

    Mallow, William A.; Dziuk, Jr., Jerome J.


    A method for calcination of a calcium carbonate material comprising heating the calcium carbonate material to a temperature and for a time sufficient to calcine the material to the degree desired while in the presence of a catalyst; said catalyst comprising at least one fused salt having the formula MCO.sub.3.CaCO.sub.3.CaO.H.sub.2 O.sub.x, wherein M is an alkali metal and x is 0 to 1 and formed by fusing MCO.sub.3 and CaCO.sub.3 in a molar ratio of about 1:2 to 2:1, and a blend adapted to be heated to CaO comprising a calcium carbonate material and at least one such fused salt.

  10. Calcium pathway machinery at fertilization in echinoderms. (United States)

    Ramos, Isabela; Wessel, Gary M


    Calcium signaling in cells directs diverse physiological processes. The calcium waves triggered by fertilization is a highly conserved calcium signaling event essential for egg activation, and has been documented in every egg tested. This activity is one of the few highly conserved events of egg activation through the course of evolution. Echinoderm eggs, as well as many other cell types, have three main intracellular Ca(2+) mobilizing messengers - IP3, cADPR and NAADP. Both cADPR and NAADP were identified as Ca(2+) mobilizing messengers using the sea urchin egg homogenate, and this experimental system, along with the intact urchin and starfish oocyte/egg, continues to be a vital tool for investigating the mechanism of action of calcium signals. While many of the major regulatory steps of the IP3 pathway are well resolved, both cADPR and NAADP remain understudied in terms of our understanding of the fundamental process of egg activation at fertilization. Recently, NAADP has been shown to trigger Ca(2+) release from acidic vesicles, separately from the ER, and a new class of calcium channels, the two-pore channels (TPCs), was identified as the likely targets for this messenger. Moreover, it was found that both cADPR and NAADP can be synthesized by the same family of enzymes, the ADP-rybosyl cyclases (ARCs). In this context of increasing amount of information, the potential coupling and functional roles of different messengers, intracellular stores and channels in the formation of the fertilization calcium wave in echinoderms will be critically evaluated. Copyright © 2012. Published by Elsevier India Pvt Ltd.

  11. 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


    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.

  12. Calcium carbonate phase transformations during the carbonation reaction of calcium heavy alkylbenzene sulfonate overbased nanodetergents preparation. (United States)

    Chen, Zhaocong; Xiao, Shan; Chen, Feng; Chen, Dongzhong; Fang, Jianglin; Zhao, Min


    The preparation and application of overbased nanodetergents with excess alkaline calcium carbonate is a good example of nanotechnology in practice. The phase transformation of calcium carbonate is of extensive concern since CaCO(3) serves both as an important industrial filling material and as the most abundant biomineral in nature. Industrially valuable overbased nanodetergents have been prepared based on calcium salts of heavy alkylbenzene sulfonate by a one-step process under ambient pressure, the carbonation reaction has been monitored by the instantaneous temperature changes and total base number (TBN). A number of analytical techniques such as TGA, DLS, SLS, TEM, FTIR, and XRD have been utilized to explore the carbonation reaction process and phase transformation mechanism of calcium carbonate. An enhanced understanding on the phase transformation of calcium carbonate involved in calcium sulfonate nanodetergents has been achieved and it has been unambiguously demonstrated that amorphous calcium carbonate (ACC) transforms into the vaterite polymorph rather than calcite, which would be of crucial importance for the preparation and quality control of lubricant additives and greases. Our results also show that a certain amount of residual Ca(OH)(2) prevents the phase transformation from ACC to crystalline polymorphs. Moreover, a vaterite nanodetergent has been prepared for the first time with low viscosity, high base number, and uniform particle size, nevertheless a notable improvement on its thermal stability is required for potential applications. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Comparison of Ferrous Calcium Silicate Slag and Calcium Ferrite Slag Interactions with Magnesia-Chrome Refractories (United States)

    Kaur, R. R.; Swinbourne, D. R.; Wadsley, M. W.; Nexhip, C.


    The cost of maintaining and eventually replacing refractories as a result of slag attack is a significant cost component in the copper industry. Converting matte to blister copper takes place in reactors lined with direct-bonded magnesia-chrome refractories, and several continuous converting operations use calcium ferrite slag. Unfortunately, the low viscosity of calcium ferrite slag makes it aggressive toward the refractories. Ferrous calcium silicate (FCS) slag has been proposed as a replacement; however, the effect of this slag on magnesia-chrome refractories has not been studied. In this work, the interactions between FCS slag and magnesia-chrome refractory at 1573 K (1300 °C) with an oxygen partial pressure of 10-6 atm were studied and compared with that experienced with calcium ferrite slag under the same conditions. Both slags penetrated the pores in the refractory and caused compositional change in the chromite spinel intergranular bonding phase through cation interdiffusion, which resulted in cracking and debonding of periclase grains. It was observed that the refractory was penetrated much more deeply by calcium ferrite slag than FCS slag because of the higher surface tension and lower viscosity of calcium ferrite slag. As a result, the refractory was attacked less by FCS slag than it was by calcium ferrite slag. It is concluded that the use of FCS slag in continuous copper converting is likely to extend refractory life.

  14. Integrated 60GHz RF beamforming in CMOS

    CERN Document Server

    Yu, Yikun; van Roermund, Arthur H M


    ""Integrated 60GHz RF Beamforming in CMOS"" describes new concepts and design techniques that can be used for 60GHz phased array systems. First, general trends and challenges in low-cost high data-rate 60GHz wireless system are studied, and the phased array technique is introduced to improve the system performance. Second, the system requirements of phase shifters are analyzed, and different phased array architectures are compared. Third, the design and implementation of 60GHz passive and active phase shifters in a CMOS technology are presented. Fourth, the integration of 60GHz phase shifters

  15. Comparison of Calcium Hydroxide and Bioactive Glass after Direct Pulp Capping in Primary Teeth

    Directory of Open Access Journals (Sweden)

    R. Haghgoo


    Full Text Available Objective: Bioactive glass is often used as a filler material for repair of dental bone defects.In different studies osteogenic potential of this material was proved, but its dentinogenesisproperty is in doubt. The purpose of this study was to evaluate the histological pulp responses of Calcium hydroxide and Bioactive glass placed directly on exposed pulp tissues.Materials and Methods: Twenty teeth to be extracted due to orthodontic reasons were selected. These teeth were divided into two groups and treated with direct pulp capping.Calcium hydroxide was used for 10 teeth and Bioactive glass for 10 teeth. After 60 daysthe teeth were extracted and prepared for histological evaluation. Finally the data was analyzed with exact Fisher test.Results: All teeth treated with Calcium hydroxide showed inflammation. Internal resorption was seen in six teeth, abscess in five teeth and dentinal bridge in two teeth. Inflammationwas seen in three Bioactive glass samples and dentinal bridge in seven teeth, but internal resorption and abscess were not seen.Conclusion: Bioactive glass appears to be superior to Calcium hydroxide as a pulp capping agent in primary teeth.

  16. Clinical effect of PRP combined with calcium dobesilate in treatment of patients with DR

    Directory of Open Access Journals (Sweden)

    Li-Bo Wang


    Full Text Available AIM: To investigate the clinical effect of panretinal photocoagulation(PRPcombined with calcium dobesilate in treatment of diabetic retinopathy(DR. METHODS: Selected 120 cases(240 eyesof DR diagnosed in our hospital from January 2011 to January 2016 were retrospectively analyzed. According to whether calcium dobesilate was used, the treatment group was divided into two groups. Sixty cases were treated with PRP combined with calcium dobesilate, and 60 cases in the control group were treated with PRP only. The BCVA, CMT and clinical efficacy of the two groups were compared. RESULTS: Before treatment, there was no significant difference on BCVA between combined group and control group(P>0.05. After treatment, BCVA of combined group was higher than that of the control group(PP>0.05; after treatment, the combination group on CMT, neovascularization and fluorescein leakage area value were less than the control group(PPCONCLUSION:PRP combined with calcium dobesilate in treatment of DR has a more significant clinical effect than PRP alone.

  17. Synthesis of some calcium phosphate crystals using the useful biomass for immobilization of microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Kohiruimaki, T, E-mail: [Department of Technology, Hachinohe Institute of Technology, 88-1 Myo-oobiraki, Hachinohe-shi 031-8501 (Japan)


    Three sources of biomass generated by primary industry were used as the raw material for the synthesis of calcium phosphate crystals. Phosphoric acid was extracted from burned rice chaff using a 30% nitric acid solution, while scallop shells and gypsum of plasterboard were used as calcium sources. The calcium phosphate crystals were synthesized by a method involving homogeneous precipitation, and the relationship between the composition and shape of the crystals and the pH at the time of the precipitation was investigated. Monetite crystals in a petal form with a diameter ranging from 0.1 to 2 {mu}m were precipitated at pH 2.0, while granular apatite crystals with a mean diameter of 1 {mu}m were precipitated at pH 6.0. We also investigated the ability of the synthesized calcium phosphate crystals to immobilize lactic acid bacteria for practical use in industrial bioreactor. It was determined that monetite crystals with a diameter of 2 {mu}m had the highest ability to fix lactic acid bacteria. The population of lactic acid bacteria was estimated to exceed 1,300 bacteria per crystal surface of 50 {mu}m{sup 2} suggesting that these crystals may be of practical use in industrial fermenters.

  18. Clinical studies of bone metabolism using a simple model of calcium tracer kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Roncari, G.


    Bone metabolism studies were performed in 44 subjects with and without bone disease using a calcium tracer kinetics model, the central feature of which is an expanding exchangeable calcium pool. In normal subjects the accretion rate and the exchangeable calcium pool ranged from 1.49 to 8.45 (mean 3.9 +- 2.05) mg.d/sup -1/kg/sup -1/ and from 60 to 131 (mean 81.25 +- 18.11) -1/, respectively. The patients with osteogenesis imperfecta, Pierre Marie's disease and one out of two cases of hypoparathyroidism had values which fell within the normal range. Both the accretion rate and the exchangeable calcium pool were significantly elevated in patients with Paget's disease and with hyperparathyroidism. Uremic patients with generalizated bone lesions had accretion rates or both parameters elevated. As far as patients with successful renal transplant are concerned, the results suggest that this method is a very poor means for detecting bone disorders with only focal lesions. In contrast, the method can be very useful when persistent renal osteodystrophy or secondary hyperparathyroidism are suspected.

  19. Strontium enhances osseointegration of calcium phosphate cement: a histomorphometric pilot study in ovariectomized rats (United States)


    Background Calcium phosphate cements are used frequently in orthopedic and dental surgeries. Strontium-containing drugs serve as systemic osteoblast-activating medication in various clinical settings promoting mechanical stability of the osteoporotic bone. Methods Strontium-containing calcium phosphate cement (SPC) and calcium phosphate cement (CPC) were compared regarding their local and systemic effects on bone tissue in a standard animal model for osteoporotic bone. A bone defect was created in the distal femoral metaphysis of 60 ovariectomized Sprague-Dawley rats. CPC and SPC were used to fill the defects in 30 rats in each group. Local effects were assessed by histomorphometry at the implant site. Systemic effects were assessed by bone mineral density (BMD) measurements at the contralateral femur and the spine. Results Faster osseointegration and more new bone formation were found for SPC as compared to CPC implant sites. SPC implants exhibited more cracks than CPC implants, allowing more bone formation within the implant. Contralateral femur BMD and spine BMD did not differ significantly between the groups. Conclusions The addition of strontium to calcium phosphate stimulates bone formation in and around the implant. Systemic release of strontium from the SPC implants did not lead to sufficiently high serum strontium levels to induce significant systemic effects on bone mass in this rat model. PMID:23758869

  20. Incorporation of bitumen and calcium silicate in cement and lime stabilized soil blocks (United States)

    Kwan, W. H.; Cheah, C. B.; Ramli, M.; Al-Sakkaf, Y. K.


    Providing affordable housing is the most critical problem in many of the developing countries. Using earth materials in building construction is one of the feasible methods to address this issue and it can be a way towards sustainable construction as well. However, the published information on the stabilized soil blocks is limited. Therefore, the present study is conducted to examine the characterization of the soils and engineering properties of the stabilized soil blocks. Four types of stabilizer were used in the study, namely; cement, slaked lime, bitumen emulsion and calcium silicate. Cement and slaked lime were added at different percentages in the range of 5% to 15%, with interval of 2.5%. The percentage was determined based on weight of soil. Meanwhile, bitumen emulsion and calcium silicate were incorporated at various percentages together with 10% of cement. Dosage of bitumen emulsion is in the range of 2% to 10% at interval of 2% while calcium silicate was incorporated at 0.50%, 0.75%, 1.00%, 1.25%, 1.50% and 2.00%. Results show that cement is the most viable stabilizer for the soil block among all stabilizers in this study. The bulk density, optimum moisture content and compressive strengths were increased with the increasing cement content. The most suitable cement content was 10% added at moisture content of 12%. Lime, bitumen and calcium contents were recommended at 5.0%, 6.0% and 1.25%, respectively.

  1. Microgravity and clinorotation cause redistribution of free calcium in sweet clover columella cells (United States)

    Hilaire, E.; Paulsen, A. Q.; Brown, C. S.; Guikema, J. A.; Spooner, B. S. (Principal Investigator)


    In higher plants, calcium redistribution is believed to be crucial for the root to respond to a change in the direction of the gravity vector. To test the effects of clinorotation and microgravity on calcium localization in higher plant roots, sweet clover (Melilotus alba L.) seedlings were germinated and grown for two days on a slow rotating clinostat or in microgravity on the US Space Shuttle flight STS-60. Subsequently, the tissue was treated with a fixative containing antimonate (a calcium precipitating agent) during clinorotation or in microgravity and processed for electron microscopy. In root columella cells of clinorotated plants, antimonate precipitates were localized adjacent to the cell wall in a unilateral manner. Columella cells exposed to microgravity were characterized by precipitates mostly located adjacent to the proximal and lateral cell wall. In all treatments some punctate precipitates were associated with vacuoles, amyloplasts, mitochondria, and euchromatin of the nucleus. A quantitative study revealed a decreased number of precipitates associated with the nucleus and the amyloplasts in columella cells exposed to microgravity as compared to ground controls. These data suggest that roots perceive a change in the gravitational field, as produced by clinorotation or space flights, and respond respectively differently by a redistribution of free calcium.

  2. Bone turnover, calcium homeostasis, and vitamin D status in Danish vegans. (United States)

    Hansen, Tue H; Madsen, Marie T B; Jørgensen, Niklas R; Cohen, Arieh S; Hansen, Torben; Vestergaard, Henrik; Pedersen, Oluf; Allin, Kristine H


    A vegan diet has been associated with increased bone fracture risk, but the physiology linking nutritional exposure to bone metabolism has only been partially elucidated. This study investigated whether a vegan diet is associated with increased bone turnover and altered calcium homeostasis due to insufficient intake of calcium and vitamin D. Fractionated and total 25-hydroxyvitamin D (25(OH)-D), parathyroid hormone (PTH), calcium, and four bone turnover markers (osteocalcin, N-terminal propeptide of type I procollagen (PINP), bone-specific alkaline phosphatase (BAP), and C-terminal telopeptide of type I collagen (CTX)) were measured in serum from 78 vegans and 77 omnivores. When adjusting for seasonality and constitutional covariates (age, sex, and body fat percentage) vegans had higher concentrations of PINP (32 [95% CI: 7, 64]%, P = 0.01) and BAP (58 [95% CI: 27, 97]%, P Vegans had higher serum PTH concentration (38 [95% CI: 19, 60]%; P Vegans have higher levels of circulating bone turnover markers compared to omnivores, which may in the long-term lead to poorer bone health. Differences in dietary habits including intake of vitamin D and calcium may, at least partly, explain the observed differences.

  3. Calcium Oxalate: A Surface Treatment for Limestone

    Directory of Open Access Journals (Sweden)

    Tody M. Cezar


    Full Text Available This paper looks at the artificially induced surface conversion of calcium carbonate to the more durable calcium oxalate. Extensive research is being carried out on wall paintings and marble sculpture at the Opicificio delle Pietre Dure e Laboratori di Restauro in Florence, Encouraged by their work, I have researched the effectiveness of the conversion on English limestones. The treated samples have been compared to untreated samples for appearance, hardness, resistance to acid and alkali, porosity, and durability. The results have been assessed considering ease of use, effectiveness, and the appropriateness of the treatment.

  4. Evolutionary Diversity of the Mitochondrial Calcium Uniporter (United States)

    Bick, Alexander G.; Calvo, Sarah E.; Mootha, Vamsi K.


    Calcium uptake into mitochondria occurs via a recently identified ion channel called the uniporter. Here, we characterize the phylogenomic distribution of the uniporter’s membrane-spanning pore subunit (MCU) and regulatory partner (MICU1). Homologs of both components tend to co-occur in all major branches of eukaryotic life, but both have been lost along certain protozoan and fungal lineages. Several bacterial genomes also contain putative MCU homologs that may represent prokaryotic calcium channels. The analyses indicate that the uniporter may have been an early feature of mitochondria. PMID:22605770

  5. Biotic Nitrogen Enrichment Regulates Calcium Sources to Forests (United States)

    Pett-Ridge, J. C.; Perakis, S. S.; Hynicka, J. D.


    Calcium is an essential nutrient in forest ecosystems that is susceptible to leaching loss and depletion. Calcium depletion can affect plant and animal productivity, soil acid buffering capacity, and fluxes of carbon and water. Excess nitrogen supply and associated soil acidification are often implicated in short-term calcium loss from soils, but the long-term role of nitrogen enrichment on calcium sources and resupply is unknown. Here we use strontium isotopes (87Sr/86Sr) as a proxy for calcium to investigate how soil nitrogen enrichment from biological nitrogen fixation interacts with bedrock calcium to regulate both short-term available supplies and the long-term sources of calcium in montane conifer forests. Our study examines 22 sites in western Oregon, spanning a 20-fold range of bedrock calcium on sedimentary and basaltic lithologies. In contrast to previous studies emphasizing abiotic control of weathering as a determinant of long-term ecosystem calcium dynamics and sources (via bedrock fertility, climate, or topographic/tectonic controls) we find instead that that biotic nitrogen enrichment of soil can strongly regulate calcium sources and supplies in forest ecosystems. For forests on calcium-rich basaltic bedrock, increasing nitrogen enrichment causes calcium sources to shift from rock-weathering to atmospheric dominance, with minimal influence from other major soil forming factors, despite regionally high rates of tectonic uplift and erosion that can rejuvenate weathering supply of soil minerals. For forests on calcium-poor sedimentary bedrock, we find that atmospheric inputs dominate regardless of degree of nitrogen enrichment. Short-term measures of soil and ecosystem calcium fertility are decoupled from calcium source sustainability, with fundamental implications for understanding nitrogen impacts, both in natural ecosystems and in the context of global change. Our finding that long-term nitrogen enrichment increases forest reliance on atmospheric

  6. The effects of intracellular pH changes on resting cytosolic calcium in voltage-clamped snail neurones (United States)

    Willoughby, Debbie; Thomas, Roger C; Schwiening, Christof J


    We have investigated the effects of changing intracellular pH on intracellular free calcium concentration ([Ca2+]i) in voltage-clamped neurones of the snail Helix aspersa. Intracellular pH (pHi) was measured using the fluorescent dye 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS) and changed using weak acids and weak bases. Changes in [Ca2+]i were recorded using either fura-2 or calcium-sensitive microelectrodes. Acidification of the neurones with 5 mM or 20 mM propionate (∼0.2 or 0.3 pH units acidification, respectively) caused a small reduction in resting [Ca2+]i of 5 ± 2 nM (n = 4) and 7 ± 16 nM (n = 4), respectively. The removal of the 20 mM propionate after ∼40 min superfusion resulted in an alkalinization of ∼0.35 pH units and an accompanying rise in resting [Ca2+]i of 31 ± 9 nM (n = 4, P Helix neurones induced by superfusion with 3 mM concentrations of the weak bases trimethylamine (TMA), ammonium chloride (NH4Cl) and procaine were accompanied by significant (P < 0.05) increases in resting [Ca2+]i of 42 ± 4 nM (n = 26), 30 ± 7 nM (n = 5) and 36 ± 4 nM (n = 3), respectively. The effect of TMA (0.5-6 mM) on [Ca2+]i was dose dependent with an increase in [Ca2+]i during pHi increases of less than 0.1 pH units (0.5 mM TMA). Superfusion of neurones with zero calcium (1 mM EGTA) Ringer solution inhibited depolarization-induced calcium increases but not the calcium increase produced by the first exposure to TMA (3 mM). In the prolonged absence of extracellular calcium (∼50 min) TMA-induced calcium rises were decreased by 64 ± 10% compared to those seen in the presence of external calcium (P < 0.05). The calcium rise induced by TMA (3 mM) was reduced by 60 ± 5% following a 10 min period of superfusion with caffeine (10 mM) to deplete the endoplasmic reticulum (ER) stores of calcium (P < 0.05). Cyclopiazonic acid (10-30 μM CPA), an inhibitor of the ER calcium pump, inhibited the calcium rise produced by TMA (3 mM) and NH4Cl (3 mM) by 61 ± 4% compared

  7. Voltage-gated calcium flux mediatesEscherichia colimechanosensation. (United States)

    Bruni, Giancarlo N; Weekley, R Andrew; Dodd, Benjamin J T; Kralj, Joel M


    Electrically excitable cells harness voltage-coupled calcium influx to transmit intracellular signals, typically studied in neurons and cardiomyocytes. Despite intense study in higher organisms, investigations of voltage and calcium signaling in bacteria have lagged due to their small size and a lack of sensitive tools. Only recently were bacteria shown to modulate their membrane potential on the timescale of seconds, and little is known about the downstream effects from this modulation. In this paper, we report on the effects of electrophysiology in individual bacteria. A genetically encoded calcium sensor expressed in Escherichia coli revealed calcium transients in single cells. A fusion sensor that simultaneously reports voltage and calcium indicated that calcium influx is induced by voltage depolarizations, similar to metazoan action potentials. Cytoplasmic calcium levels and transients increased upon mechanical stimulation with a hydrogel, and single cells altered protein concentrations dependent on the mechanical environment. Blocking voltage and calcium flux altered mechanically induced changes in protein concentration, while inducing calcium flux reproduced these changes. Thus, voltage and calcium relay a bacterial sense of touch and alter cellular lifestyle. Although the calcium effectors remain unknown, these data open a host of new questions about E. coli , including the identity of the underlying molecular players, as well as other signals conveyed by voltage and calcium. These data also provide evidence that dynamic voltage and calcium exists as a signaling modality in the oldest domain of life, and therefore studying electrophysiology beyond canonical electrically excitable cells could yield exciting new findings.

  8. Calcium intake, polymorphisms of the calcium-sensing receptor, and recurrent/aggressive prostate cancer. (United States)

    Binder, Moritz; Shui, Irene M; Wilson, Kathryn M; Penney, Kathryn L; Mucci, Lorelei A; Kibel, Adam S


    To assess whether calcium intake and common genetic variants of the calcium-sensing receptor (CASR) are associated with either aggressive prostate cancer (PCa) or disease recurrence after prostatectomy. Calcium intake at diagnosis was assessed, and 65 common single-nucleotide polymorphisms (SNPs) in CASR were genotyped in 886 prostatectomy patients. We investigated the association between calcium intake and CASR variants with both PCa recurrence and aggressiveness (defined as Gleason score ≥4 + 3, stage ≥pT3, or nodal-positive disease). A total of 285 men had aggressive disease and 91 experienced recurrence. A U-shaped relationship between calcium intake and both disease recurrence and aggressiveness was observed. Compared to the middle quintile, the HR for disease recurrence was 3.07 (95% CI 1.41-6.69) for the lowest quintile and 3.21 (95% CI 1.47-7.00) and 2.97 (95% CI 1.37-6.45) for the two upper quintiles, respectively. Compared to the middle quintile, the OR for aggressive disease was 1.80 (95% CI 1.11-2.91) for the lowest quintile and 1.75 (95% CI 1.08-2.85) for the highest quintile of calcium intake. The main effects of CASR variants were not associated with PCa recurrence or aggressiveness. In the subgroup of patients with moderate calcium intake, 31 SNPs in four distinct blocks of high linkage disequilibrium were associated with PCa recurrence. We observed a protective effect of moderate calcium intake for PCa aggressiveness and recurrence. While CASR variants were not associated with these outcomes in the entire cohort, they may be associated with disease recurrence in men with moderate calcium intakes.

  9. Do calcium buffers always slow down the propagation of calcium waves? (United States)

    Tsai, Je-Chiang


    Calcium buffers are large proteins that act as binding sites for free cytosolic calcium. Since a large fraction of cytosolic calcium is bound to calcium buffers, calcium waves are widely observed under the condition that free cytosolic calcium is heavily buffered. In addition, all physiological buffered excitable systems contain multiple buffers with different affinities. It is thus important to understand the properties of waves in excitable systems with the inclusion of buffers. There is an ongoing controversy about whether or not the addition of calcium buffers into the system always slows down the propagation of calcium waves. To solve this controversy, we incorporate the buffering effect into the generic excitable system, the FitzHugh-Nagumo model, to get the buffered FitzHugh-Nagumo model, and then to study the effect of the added buffer with large diffusivity on traveling waves of such a model in one spatial dimension. We can find a critical dissociation constant (K = K(a)) characterized by system excitability parameter a such that calcium buffers can be classified into two types: weak buffers (K ∈ (K(a), ∞)) and strong buffers (K ∈ (0, K(a))). We analytically show that the addition of weak buffers or strong buffers but with its total concentration b(0)(1) below some critical total concentration b(0,c)(1) into the system can generate a traveling wave of the resulting system which propagates faster than that of the origin system, provided that the diffusivity D1 of the added buffers is sufficiently large. Further, the magnitude of the wave speed of traveling waves of the resulting system is proportional to √D1 as D1 --> ∞. In contrast, the addition of strong buffers with the total concentration b(0)(1) > b(0,c)(1) into the system may not be able to support the formation of a biologically acceptable wave provided that the diffusivity D1 of the added buffers is sufficiently large.

  10. Vitamin d deficiency is associated with insulin resistance independent of intracellular calcium, dietary calcium and serum levels of parathormone, calcitriol and calcium in premenopausal women. (United States)

    Ferreira, Thaís da Silva; Rocha, Tatiana Martins; Klein, Márcia Regina Simas Torres; Sanjuliani, Antonio Felipe


    There is evidence that vitamin D deficiency is associated with increased risk of cardiovascular disease. However, it is not known if this association is independent of dietary calcium, intracellular calcium and serum levels of parathormone, calcitriol and calcium. To investigate the independent relationship of vitamin D deficiency with insulin resistance, lipid profile, inflammatory status, blood pressure and endothelial function. Cross-sectional study conducted with 73 healthy Brazilian premenopausal women aged 18 - 50 years. All participants were evaluated for: 25 hydroxyvitamin D serum levels, anthropometric parameters, body composition, calcium metabolism, insulin resistance, lipoprotein profile, inflammatory status, blood pressure and endothelial function. Endothelial function was assessed by reactive hyperemia index using Endo-PAT 2000®. Women were stratified in two groups: with vitamin D deficiency (25 hydroxyvitamin D independent of dietary calcium, intracellular calcium and serum levels of parathormone, calcitriol and calcium in healthy premenopausal women. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  11. Raman Laser Polymerization of C60 Nanowhiskers

    Directory of Open Access Journals (Sweden)

    Ryoei Kato


    Full Text Available Photopolymerization of C60 nanowhiskers (C60NWs was investigated by using a Raman spectrometer in air at room temperature, since the polymerized C60NWs are expected to exhibit a high mechanical strength and a thermal stability. Short C60NWs with a mean length of 4.4 μm were synthesized by LLIP method (liquid-liquid interfacial precipitation method. The Ag(2 peak of C60NWs shifted to the lower wavenumbers with increasing the laser beam energy dose, and an energy dose more than about 1520 J/mm2 was found necessary to obtain the photopolymerized C60NWs. However, excessive energy doses at high-power densities increased the sample temperature and lead to the thermal decomposition of polymerized C60 molecules.

  12. Avian eggshell formation in calcium-rich and calcium-poor habitats: Importance of snail shells and anthropogenic calcium sources

    NARCIS (Netherlands)

    Graveland, J.


    Most passerines depend on the intake of calcium-rich material in addition to their normal food for proper eggshell formation and skeletal growth. A large proportion of Great Tits (Pants major) in forests on nutrient-poor soils in the Netherlands produce eggs with defective shells as a result of

  13. Synthesis of Portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance (United States)

    Chen, Irvin Allen

    Portland cement concrete, the most widely used manufactured material in the world, is made primarily from water, mineral aggregates, and portland cement. The production of portland cement is energy intensive, accounting for 2% of primary energy consumption and 5% of industrial energy consumption globally. Moreover, portland cement manufacturing contributes significantly to greenhouse gases and accounts for 5% of the global CO2 emissions resulting from human activity. The primary objective of this research was to explore methods of reducing the environmental impact of cement production while maintaining or improving current performance standards. Two approaches were taken, (1) incorporation of waste materials in portland cement synthesis, and (2) optimization of an alternative environmental friendly binder, calcium sulfoaluminate-belite cement. These approaches can lead to less energy consumption, less emission of CO2, and more reuse of industrial waste materials for cement manufacturing. In the portland cement part of the research, portland cement clinkers conforming to the compositional specifications in ASTM C 150 for Type I cement were successfully synthesized from reagent-grade chemicals with 0% to 40% fly ash and 0% to 60% slag incorporation (with 10% intervals), 72.5% limestone with 27.5% fly ash, and 65% limestone with 35% slag. The synthesized portland cements had similar early-age hydration behavior to commercial portland cement. However, waste materials significantly affected cement phase formation. The C3S--C2S ratio decreased with increasing amounts of waste materials incorporated. These differences could have implications on proportioning of raw materials for cement production when using waste materials. In the calcium sulfoaluminate-belite cement part of the research, three calcium sulfoaluminate-belite cement clinkers with a range of phase compositions were successfully synthesized from reagent-grade chemicals. The synthesized calcium sulfoaluminate

  14. Localization of calcium signals by a mobile calcium buffer in frog saccular hair cells. (United States)

    Roberts, W M


    A recent study (Roberts, 1993) of saccular hair cells from grass frogs (Rana pipiens) has suggested a mechanism by which the unusually high concentrations of calcium-binding proteins found in certain sensory receptors and neurons, particularly in the auditory system, can influence short-range intracellular calcium signaling. In frog saccular hair cells, the mechanism operates within arrays of calcium channels and calcium-activated potassium channels that are involved in the cells' electrical resonance and synaptic transmission. The present study tests the hypothesis that calbindin-D28k, one of the most abundant proteins in these cells, can serve as a mobile calcium buffer that reduces and localizes changes in the intracellular free-calcium concentration ([Ca2+]i) by shuttling calcium away from the channel arrays. Based upon theoretical analysis and computer modeling, it is shown that [Ca2+]i near one or more open channels quickly reaches a steady-state level determined primarily by two properties of the buffer, the mean time (tau c) before it captures a free-calcium ion and a replenishment factor (R), which are related to the buffer's diffusional mobility (DBu), association rate constant (kon), and concentration (Bo) by tau c = (konB0)-1 and R = B0DBu. Simulation of calcium entry through a channel array showed that approximately 1.5 mM of a molecule with the diffusional and binding properties expected for calbindin-D28k (Bo approximately 8 mM calcium-binding sites) is needed to reproduce the previous experimental results. A lower concentration (B0 = 2 mM) was almost completely depleted within the channel array by a modest calcium current (8 pA = 12% of calcium channels open), but still had two important effects: it caused [Ca2+]i to fall steeply with distance outside the array (space constant < 50 nm), and returned [Ca2+]i quickly to the resting level after the channels closed. A high concentration of calbindin-D28k can thus influence the cell's electrical

  15. Effects of extracellular calcium on calcium transport during hyperthermia of tumor cells. (United States)

    Anghileri, L J; Marcha, C; Crone-Escanyé, M C; Robert, J


    The effects of different concentrations of extracellular ion calcium on the transport of calcium by tumor cells have been studied by means of the uptake of radiocalcium. Tumor cells incubated at 45 degrees C take up 4-10 times the amount of radioactivity incorporated by cells incubated at 37 degrees C. The difference is still greater (up to 100 times) for the intracellular incorporation as assessed by elimination of the membrane-bound calcium by EGTA treatment. The possible mechanisms involved in this differential behavior are discussed.

  16. Degree of vinyl conversion in experimental amorphous calcium phosphate composites (United States)

    Tarle, Z.; Knežević, A.; Matošević, D.; Škrtić, D.; Ristić, M.; Prskalo, K.; Musić, S.


    An experimental dental composite, based on amorphous calcium phosphate (ACP) with the potential to arrest caries development and regenerate mineral-deficient tooth structures has recently been developed. The aim of this study was to assess the degree of vinyl conversion (DVC) attained in experimental composites based on zirconia-modified ACP. Photo-activated resins were based on ethoxylated bisphenol A dimethacrylate (EBPADMA) [ETHM series with varying EBPADMA/triethylene glycol dimethacrylate (TEGDMA) molar ratios assigned 0.5-ETHM I, 0.85-ETHM II and 1.35-ETHM III], or 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]-propane (Bis-GMA) [BTHZ series]. To asses a possible effect of filler particle size on DVC, composites containing 60 mass % resin and 40 mass % of either milled ACP (mACP; median diameter d m = 0.9 μm) or coarse ACP (cACP; d m = 6.0 μm) were prepared, and irradiated with LED curing unit for 40 s. The DVC was calculated as the % change in the ratio of the integrated peak areas between the aliphatic and aromatic absorption bands determined by Fourier transform infrared spectroscopy (FTIR). The highest DVCs values were attained in mACP-BTHZ, cACP-BTHZ and mACP-ETHM III formulations. DVC of tested ACP composites (on average (76.76 ± 4.43)%) compares well with or exceeds DVCs values reported for the majority of commercial materials.

  17. Biological applications of hydrophilic C60 derivatives (hC60s)- a structural perspective. (United States)

    Zhu, Xiaolei; Sollogoub, Matthieu; Zhang, Yongmin


    Reactive oxygen species (ROS) generation and radical scavenging are dual properties of hydrophilic C60 derivatives (hC60s). hC60s eliminate radicals in dark, while they produce reactive oxygen species (ROS) in the presence of irradiation and oxygen. Compared to the pristine C60 suspension, the aqueous solution of hC60s is easier to handle in vivo. hC60s are diverse and could be placed into two general categories: covalently modified C60 derivatives and pristine C60 solubilized non-covalently by macromolecules. In order to present in detail, the above categories are broken down into 8 parts: C60(OH)n, C60 with carboxylic acid, C60 with quaternary ammonium salts, C60 with peptide, C60 containing sugar, C60 modified covalently or non-covalently solubilized by cyclodextrins (CDs), pristine C60 delivered by liposomes, functionalized C60-polymer and pristine C60 solubilized by polymer. Each hC60 shows the propensity to be ROS producer or radical scavenger. This preference is dependent on hC60s structures. For example, major application of C60(OH)n is radical scavenger, while pristine C60/γ-CD complex usually serves as ROS producer. In addition, the electron acceptability and innate hydrophobic surface confer hC60s with O2 uptake inhibition, HIV inhibition and membrane permeability. In this review, we summarize the preparation methods and biological applications of hC60s according to the structures. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Simplified Citrate Anticoagulation for CRRT Without Calcium Replacement. (United States)

    Broman, Marcus; Klarin, Bengt; Sandin, Karin; Carlsson, Ola; Wieslander, Anders; Sternby, Jan; Godaly, Gabriela


    Since 2012, citrate anticoagulation is the recommended anticoagulation strategy for continuous renal replacement therapy (CRRT). The main drawback using citrate as anticoagulant compared with heparin is the need for calcium replacement and the rigorous control of calcium levels. This study investigated the possibility to achieve anticoagulation while eliminating the need for calcium replacement. This was successfully achieved by including citrate and calcium in all CRRT solutions. Thereby the total calcium concentration was kept constant throughout the extracorporeal circuit, whereas the ionized calcium was kept at low levels enough to avoid clotting. Being a completely new concept, only five patients with acute renal failure were included in a short, prospective, intensely supervised nonrandomized pilot study. Systemic electrolyte levels and acid-base parameters were stable and remained within physiologic levels. Ionized calcium levels declined slightly initially but stabilized at 1.1 mmol/L. Plasma citrate concentrations stabilized at approximately 0.6 mmol/L. All postfilter ionized calcium levels were CRRT.

  19. Calcium and Iron Levels in Some Fruits and Vegetables Commonly ...

    African Journals Online (AJOL)

    , Cabbage, Pepper, Spinach, and Tomato) in each case were analysed for their Calcium and iron levels using spectrophotometric method of analysis; From the results, it was found that the concentration of Calcium was highest in spinach ...

  20. Calcium supplementation to prevent pre-eclampsia - a systematic ...

    African Journals Online (AJOL)

    Calcium supplementation to prevent pre-eclampsia - a systematic review. ... To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child adverse ... Article Metrics.

  1. The effect of farmyard manure and calcium ammonium nitrate ...

    African Journals Online (AJOL)

    The effect of farmyard manure and calcium ammonium nitrate fertilisers on micronutrient density (iron, zinc, manganese, calcium and potassium) and seed yields of solanium villosum (black nightshade) and cleome gynandra (cat whiskers) on uetric nitisol.

  2. Peanut (Arachis hypogaea L.) Cultivar Response to Prohexadione Calcium (United States)

    Peanut digging efficiency can be reduced if row visibility is limited by excessive vegetation. The plant growth regulator prohexadione calcium retards vegetative growth and improves row visibility by inhibiting internode elongation. In some instances, prohexadione calcium also increases pod yield....

  3. Astrocyte calcium signalling orchestrates neuronal synchronization in organotypic hippocampal slices (United States)

    Sasaki, Takuya; Ishikawa, Tomoe; Abe, Reimi; Nakayama, Ryota; Asada, Akiko; Matsuki, Norio; Ikegaya, Yuji


    Astrocytes are thought to detect neuronal activity in the form of intracellular calcium elevations; thereby, astrocytes can regulate neuronal excitability and synaptic transmission. Little is known, however, about how the astrocyte calcium signal regulates the activity of neuronal populations. In this study, we addressed this issue using functional multineuron calcium imaging in hippocampal slice cultures. Under normal conditions, CA3 neuronal networks exhibited temporally correlated activity patterns, occasionally generating large synchronization among a subset of cells. The synchronized neuronal activity was correlated with astrocyte calcium events. Calcium buffering by an intracellular injection of a calcium chelator into multiple astrocytes reduced the synaptic strength of unitary transmission between pairs of surrounding pyramidal cells and caused desynchronization of the neuronal networks. Uncaging the calcium in the astrocytes increased the frequency of neuronal synchronization. These data suggest an essential role of the astrocyte calcium signal in the maintenance of basal neuronal function at the circuit level. PMID:24710057

  4. Calcium Supplements: A Risk Factor for Heart Attack? (United States)

    ... factor for heart attack? I've read that calcium supplements may increase the risk of heart attack. ... D. Some doctors think it's possible that taking calcium supplements may increase your risk of a heart ...

  5. Calcium Supplements: Do They Interfere with Blood Pressure Drugs? (United States)

    ... with blood pressure drugs? Is it true that calcium supplements may interact with blood pressure medications? Answers ... G. Sheps, M.D. Yes. In large amounts, calcium supplements may interact with some blood pressure medications. ...

  6. Beyond-root calcium fertilization of apple trees

    Directory of Open Access Journals (Sweden)

    Kazimierz Słowik


    Full Text Available Investigations were performed in the period 1977-1979 on the apple tree cultivar 'Fantazja', on rootstock A 2, M 7 and MM 106 on the effect of spraying with solution containing calcium on the incidence of bitter pit, breakdown, calcium content in the fruit flesh and other features of the fruits. Threefold spraying with calcium nitrate, calcium chloride or Anti-Stipp significantly limited the appearance of bitter pit and breakdown.

  7. Calcium Intake in Elderly Australian Women Is Inadequate

    Directory of Open Access Journals (Sweden)

    Colin W. Binns


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

  8. Modulation of L-type calcium channels by sodium ions.


    Balke, C W; Wier, W G


    It is universally believed that the removal of external sodium ions is without effect on calcium current. We now report that in enzymatically isolated guinea pig ventricular cells, the replacement of external sodium ions with certain other cations causes a 3- to 6-fold increase in peak L-type calcium current. The increase in current is reversibly blocked by L-type calcium-channel antagonists, not mediated by changes in internal calcium, and is inhibited by intracellular 5'-adenylyl imidodipho...

  9. How calcium makes endocytic receptors attractive

    DEFF Research Database (Denmark)

    Andersen, Christian B F; Moestrup, Søren K


    '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...

  10. Drying and Rehydration of Calcium Alginate Gels

    NARCIS (Netherlands)

    Vreeker, R.; Li, L.; Fang, Y.; Appelqvist, I.; Mendes, E.


    In this paper, we study the rehydration properties of air-dried calcium alginate gel beads. Rehydration is shown to depend on alginate source (i.e. mannuronic to guluronic acid ratio) and the salt concentration in the rehydration medium. Rehydration curves are described adequately by the empirical

  11. Pharmacological analysis of calcium antagonist receptors

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, I.J.


    This work focuses on two aspects of the action of calcium antagonist drugs, namely, the interaction of drugs with receptors for verapamil-like calcium antagonists, and the interactions of drugs with voltage-sensitive calcium fluxes in rat brain synaptosomes. From binding studies I have found that the ligand of choice for labeling the verapamil receptor is (-)(/sup 3/H)desmethoxy-verapamil. This drug labels potently, reversibly and stereoselectively two receptors in membranes prepared from rat brain and rabbit skeletal muscle tissues. In equilibrium studies dihydropyridine calcium antagonists interact in a non-competitive fashion, while many non-DHPs are apparently competitive. In-depth kinetic studies in skeletal muscle membranes indicate that the two receptors are linked in a negative heterotropic fashion, and that low-affinity binding of (-) (/sup 3/H)desmethoxy-verapamil may be to the diltiazem receptor. However, these studies were not able to distinguish between the hypothesis that diltiazem binds to spatially separate, allosterically coupled receptors, and the hypothesis that diltiazem binds to a subsite of the verapamil receptor.

  12. Physicochemical characterization of zinc-substituted calcium ...

    Indian Academy of Sciences (India)

    On the contrary, no changes of the crystallinity were observed for the brushite doped with Zn ions. Morphology of attained powders, visualized using scanningelectron microscopy exemplified structural changes between calcium phosphates conjugated with zinc ions. Many authors report that the addition of small amounts of ...

  13. Simulating cement microstructural evolution during calcium leaching

    NARCIS (Netherlands)

    Patel, R.A.; Perko, J.; Jacques, D.; De Schutter, G.; Van Breugel, K.; Ye, G.


    Calcium leaching is one of the important degradation mechanisms causing dissolution of the crystalline phases such as, AFm, portlandite increasing capillary porosity. Further it leads to decalcification of an amorphous C-S-H phase causing increase in the gel porosity and in turn degrading the long

  14. Serum Calcium, Inorganic Phosphates and some Haematological ...

    African Journals Online (AJOL)

    Objectives: Sickle cell disease has long been associated with bone deformities and pain. Mineral salts such as calcium and inorganic phosphate are critical in bone formation and metabolism. This investigation was designed to study the serum concentration of these minerals as well as some haematological parameters in ...

  15. 21 CFR 582.5217 - Calcium phosphate. (United States)


    ... 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 DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  16. 21 CFR 582.5210 - Calcium oxide. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium oxide. 582.5210 Section 582.5210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

  17. 21 CFR 582.5223 - Calcium pyrophosphate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium pyrophosphate. 582.5223 Section 582.5223 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  18. 21 CFR 582.5212 - Calcium pantothenate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium pantothenate. 582.5212 Section 582.5212 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  19. 21 CFR 582.5230 - Calcium sulfate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium sulfate. 582.5230 Section 582.5230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  20. 21 CFR 582.5195 - Calcium citrate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium citrate. 582.5195 Section 582.5195 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  1. 21 CFR 582.5201 - Calcium glycerophosphate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium glycerophosphate. 582.5201 Section 582.5201 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or...


    African Journals Online (AJOL)



    Mar 3, 2005 ... Objective: To assess the role of calcium in the development of clinical rickets among. Ethiopian children coming to Jimma Specialised Hospital outpatient, department. Design: Case control study. Settings: Jimma Specialised Teaching Hospital and surrounding urban and rural community in the catchment ...

  3. An improved calcium chloride method preparation and ...

    African Journals Online (AJOL)

    In this paper, we have reported a modified method for preparation and transformation of competent cells. This modified method, improved from a classical protocol, has made some modifications on the concentration of calcium chloride and competent bacteria solution, rotation speed in centrifugation and centrifugation time.

  4. Biocompatibility of bio based calcium carbonate nanocrystals ...

    African Journals Online (AJOL)

    Material and Methods: Transmission and field emission scanning electron microscopy (TEM and FESEM) were used for the characterisation of CaCO3 nanocrystals. Cytotoxicity and genotoxic effect of calcium carbonate nanocrystals in cultured mouse embryonic fibroblast NIH 3T3 cell line using various bioassays including ...

  5. Calcium carbonate precipitation by different bacterial strains ...

    African Journals Online (AJOL)

    Bacteria are capable of performing metabolic activities which thereby promote precipitation of calcium carbonate in the form of calcite. In this study, it is shown that microbial mineral precipitation was a result of metabolic activities of some specific microorganisms. Concrete microorganisms were used to improve the overall ...

  6. Fabrication and Evaluation of Rosuvastatin Calcium Fast ...

    African Journals Online (AJOL)

    Available online at · Original ... Revised accepted: 6 October 2015. Abstract. Purpose: To formulate fast-disintegrating tablets (FDT) of rosuvastatin calcium (RST) using β- ... promote dissolution, absorption and ultimately bioavailability thereby reducing particle size or.

  7. Calcium enhances cadmium tolerance and decreases cadmium ...

    African Journals Online (AJOL)

    These results suggest that cadmium uptake in lettuce plants is negatively associated with the presence of calcium in the culture medium, maybe due to a competition between these two cations for binding and absorption sites in roots. In conclusion, the results suggest that fertilization with Ca2+ appears to be a promising ...

  8. Osteophagia provide giraffes with phosphorus and calcium? (United States)

    Bredin, I P; Skinner, J D; Mitchell, G


    The daily requirement for calcium and phosphorus by giraffes to sustain the growth and maintenance of their skeletons is large. The source of sufficient calcium is browse. The source of necessary phosphorus is obscure, but it could be osteophagia, a frequently observed behaviour in giraffes. We have assessed whether bone ingested as a result of osteophagia can be digested in the rumen. Bone samples from cancellous (cervical vertebrae) and dense bones (metacarpal shaft) were immersed in the rumens of five sheep, for a period of up to 30 days, and the effect compared to immersion in distilled water and in artificial saliva for 30 days. Distilled water had no effect on the bones. Dense bone samples were softened by exposure to the saliva and rumen fluid, but did not lose either calcium or phosphorus. In saliva and rumen fluid the cancellous bone samples also softened, and their mass and volume decreased as a result of exposure to saliva, but in neither fluid did they lose significant amounts of calcium and phosphorus. We conclude that although saliva and rumen fluid can soften ingested bones, there is an insignificant digestion of bones in the rumen.

  9. [Intra-cystic renal calcium milk]. (United States)

    Meunier, B; Médart, L; Massart, J P; Collignon, L


    Intra-cystic renal calcium milk is a rare entity. The authors report a clinical case, and describe the radiographic and tomodensitometric appearances. This 50 year old patient has been followed up for more than ten years for urinary lithiasis with recurrent pain.

  10. Isolation and characterization of biogenic calcium carbonate ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 39; Issue 2. Isolation and characterization of biogenic calcium carbonate/phosphate from oral bacteria and their adhesion studies on YSZ-coated titanium substrate for dental implant application. GOBI SARAVANAN KALIARAJ KAMALAN KIRUBAHARAN G ...

  11. 76 FR 71459 - Prohexadione Calcium; Pesticide Tolerances (United States)


    ... requested that 40 CFR 180.547 be amended by establishing tolerances for residues of the plant growth... subgroups of consumers, including infants and children. Prohexadione calcium is not acutely toxic by the..., and kidneys were the target organ for toxicity in the dogs. Following repeated dermal exposures for 28...

  12. Effect of Ultrasound on Calcium Carbonate Crystallization

    NARCIS (Netherlands)

    Wagterveld, R.M.


    Scaling comprises the formation of hard mineral deposits on process or membrane equipment and calcium carbonate is the most common scaling salt. Especially in reverse osmosis (RO) membrane systems, scale formation has always been a serious limitation, causing flux decline, membrane degradation, loss

  13. Exploring the calcium isotope signature of

    NARCIS (Netherlands)

    Hippler, D.; Witbaard, R.; van Aken, H.M.; Buhl, D.; Immenhauser, A.


    The calcium-isotope composition (delta Ca-44/40) of the aragonitic bivalve Arctica islandica grown in laboratory and field cultures was investigated in terms of environmental and biological controls to explore its potential as a palaeoceanographic proxy. While we found no significant effect of

  14. Thermoluminescence dosimetry of rare earth doped calcium ...

    Indian Academy of Sciences (India)

    The thermoluminescence (TL) properties of calcium aluminate (CaAl2O4) doped with different rare earth ions have been studied and their suitability for radiation dosimetry applications is discussed. It is observed that monocalcium aluminate doped with cerium is a good dosimeter having linear response up to about 4 kGy of ...

  15. Effects of Calcium Ion, Calpains, and Calcium Channel Blockers on Retinitis Pigmentosa

    Directory of Open Access Journals (Sweden)

    Mitsuru Nakazawa


    Full Text Available Recent advances in molecular genetic studies have revealed many of the causative genes of retinitis pigmentosa (RP. These achievements have provided clues to the mechanisms of photoreceptor degeneration in RP. Apoptosis is known to be a final common pathway in RP and, therefore, a possible therapeutic target for photoreceptor rescue. However, apoptosis is not a single molecular cascade, but consists of many different reactions such as caspase-dependent and caspase-independent pathways commonly leading to DNA fractionation and cell death. The intracellular concentration of calcium ions is also known to increase in apoptosis. These findings suggest that calpains, one of the calcium-dependent proteinases, play some roles in the process of photoreceptor apoptosis and that calcium channel antagonists may potentially inhibit photoreceptor apoptosis. Herein, the effects of calpains and calcium channel antagonists on photoreceptor degeneration are reviewed.

  16. Successful pregnancy and childbirth after intracytoplasmic sperm injection with calcium ionophore oocyte activation in a globozoospermic patient. (United States)

    Tejera, Alberto; Mollá, Marta; Muriel, Lourdes; Remohí, Jose; Pellicer, Antonio; De Pablo, Jose Luis


    To check the effectiveness of intracytoplasmic sperm injection (ICSI) combined with assisted oocyte activation (AOA) in a globozoospermic patient. Case report. Instituto Valenciano de Infertilidad, Valencia, Spain. A patient with globozoospermia. ICSI was administered in 14 oocytes. ICSI combined with AOA, in which a small amount of calcium was injected followed by calcium ionophore exposure, was done in 9 oocytes. Fertilization rate and embryo quality was assessed in both groups. Chemical activation increased fertilization rate (55.6% vs. 35.7%) and the number of embryos with less multinucleation on day 2 (0 vs. 60%). Two embryos generated from AOA were transferred into the uterus (on day 3), resulting in a pregnancy and a healthy newborn. The AOA with calcium ionophore treatment improved fertilization rate and quality of the embryos, and was found to be an effective method for AOA in this patient with a low fertilization rate after previous ICSI treatment.

  17. Altered calcium metabolism: the probable major biochemical lesion ...

    African Journals Online (AJOL)

    These data are suggestive of altered calcium metabolism impairing cell membrane stabilization, the vasorelaxing effect of calcium and cell signaling. Altered calcium metabolism may be the major biochemical lesion underlying many pathological and clinical states of lead toxicity. Journal of Biomedical Investigation Vol.

  18. Dietary calcium intake and sunlight exposure among children aged ...

    African Journals Online (AJOL)

    Nutritional rickets can be caused by either or both calcium and vitamin D deficiencies, and can frequently occur in Africa. In Ethiopia, limited evidence exists regarding the calcium intake of children and their sunlight exposure practices. The purpose of this study was to assess information regarding dietary calcium intake and ...

  19. Magnesium: Origin and role in calcium-treated inclusions

    CSIR Research Space (South Africa)

    Pistorius, CP


    Full Text Available in calcium-treated steel is not fully clear, nor is the origin of the several percent of magnesium oxide that is often present in calcium-treated inclusions. To study this, steel was sampled after calcium treatment at an industrial steel plant...

  20. Enhanced expression of a calcium-dependent protein kinase from ...

    Indian Academy of Sciences (India)

    Among the downstream targets of calcium in plants, calcium-dependent protein kinases (CDPKs) form an interesting class of kinases which are activated by calcium binding. They have been implicated in a diverse array of responses to hormonal and environmental stimuli. In order to dissect the role of CDPKs in the moss ...

  1. Serum Calcium Level is Associated with Lipids in Young Nigerian ...

    African Journals Online (AJOL)

    cholesterol (VLDL‑c), total lipids and total calcium were assayed in 160 young women (110 OCP users and 50 controls) using colorimetric ... Emokpae and Uadia: Serum calcium correlates with lipid levels in women using low dose oral contraceptive pills ..... by increasing calcium absorption from diet in the intestine.

  2. Transfected parvalbumin alters calcium homeostasis in teratocarcinoma PCC7 cells

    DEFF Research Database (Denmark)

    Müller, B K; Kabos, P; Belhage, B


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

  3. Interactions of genotype, housing and dietary calcium in layer ...

    African Journals Online (AJOL)



    Aug 31, 2016 ... Castillo, C., Cuca, M., Pro, A., González, M. & Morales, E., 2004. Biological and economic optimum level of calcium in white leghorn laying hens. Poult. Sci. 83, 868-872. Cheng, T.K. & Coon, C.N., 1990. Effect of calcium source, particle size, limestone solubility in vitro and calcium intake level on layer bone ...

  4. Transfected parvalbumin alters calcium homeostasis in teratocarcinoma PCC7 cells

    DEFF Research Database (Denmark)

    Müller, B K; Kabos, P; Belhage, B


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

  5. Effect of nutrient calcium on the cell wall composition and ...

    African Journals Online (AJOL)

    The effect of calcium in the nutrient medium on kikuyu grass (Pennisetum clandestinum Hochst), grown in a solution culture, was investigated. Calcium had no effect on the lignin content of leaf material, but decreased the lignin content per unit stem cell wall. Calcium appeared to have no significant effect on either the ...

  6. FLIPR assays of intracellular calcium in GPCR drug discovery

    DEFF Research Database (Denmark)

    Hansen, Kasper Bø; Bräuner-Osborne, Hans


    -Galpha(q)-coupled GPCRs can be tweaked to modulate intracellular calcium by co-transfection with promiscuous or chimeric/mutated G proteins making the calcium assays broadly applicable in GPCR research. Third, the price of instruments capable of measuring fluorescent-based calcium indicators has become significantly less...

  7. Calcium and Vitamin D: Important at Every Age (United States)

    ... 100 Turnip greens, boiled, ½ cup 99 Broccoli, raw, 1 cup 90 Ice cream, vanilla, ½ cup 85 Soy or rice milk, fortified with calcium, 1 cup 80–500 (varies) Calcium Culprits Although a balanced diet aids calcium absorption, high levels of protein and ...

  8. Transfected parvalbumin alters calcium homeostasis in teratocarcinoma PCC7 cells

    DEFF Research Database (Denmark)

    Müller, B K; Kabos, P; Belhage, B


    Indirect evidence supports a protective role of some EF-hand calcium-binding proteins against calcium-induced neurotoxicity. Little is known about how these proteins influence cytosolic calcium levels. After cloning the parvalbumin cDNA into an expression vector, teratocarcinoma cells (PCC7) were...

  9. 21 CFR 582.6215 - Monobasic calcium phosphate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Monobasic calcium phosphate. 582.6215 Section 582.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use. This...

  10. 21 CFR 182.6215 - Monobasic calcium phosphate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Monobasic calcium phosphate. 182.6215 Section 182.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use. This...

  11. [Antiamyloid properties of fullerene C60 derivatives]. (United States)

    Bobylev, A G; Shpagina, M D; Bobyleva, L G; Okuneva, A D; Piotrovskiĭ, L B; Podlubnaia, Z A


    A comparative estimation of the ability of complexes of fullerene C60 with polyvinylpyrrolidone and fullerene C60 derivatives (the sodium salt of the polycarboxylic derivative of fullerene C60, sodium fullerenolate), has been carried out. The fullerenes destroyed amyloid fibrils of the Abeta(1-42) peptide of the brain and the muscle X-protein. A study of the effect of fullerenes on muscle actin showed that complexes of fullerene C60 with polyvinylpyrrolidone and sodium fullerenolate did not prevent the filament formation of actin, nor did they destroy its filaments in vitro. Conversely, sodium salt of the polycarboxylic derivative of fullerene C60 destroyed actin filaments and prevented their formation. It was concluded that sodium fullerenolate and complexes of fullerene C60 with polyvinylpyrrolidone are the most effective antiamyloid compounds among the fullerenes examined.

  12. Diagnosis of alterations of serum calcium metabolism. (United States)

    Lumachi, Franco; Cappelletti, Piero; Tozzoli, Renato; Basso, Stafano M M; Luisetto, Giovanni; Camozzi, Valentina


    Calcium is essential to homeostasis and functioning of multiple organ systems. Its circulating concentration is maintained within a very tight physiologic range: 2.25 and 2.50 mmol/L. Under physiological conditions, the ionized calcium concentration is regulated by the parathyroid hormone (PTH), and 1,25(OH)(2) vitamin D through interactions on target organs such as kidney, bone and intestine. In mild, moderate, and severe hypercalcemia, laboratory findings are essential in assessing and monitoring disease course and therapy. The main tools are specific standard biochemical tests able to assess calcium balance and renal function, and some specific biochemical tests, such as PTH, 25(OH) vitamin D, and genetic sequencing, used to clarify the cause of hypercalcemia and, subsequently, to determine appropriate therapy. Once hypercalcemia is confirmed by ionized calcium measurement, the intact PTH assay plays a crucial role to differentiate PTH-mediated from non-PTH-mediated hypercalcemia. Mild hypercalcemia is also present in up to 10-20% of patients treated with lithium for bipolar disorders, in 7-8% of those treated with thiazide diuretics, and in patients with prolonged immobilization, while very high (>3.5 mmol/L) serum calcium levels, together with low PTH, and a rapid increase of hypercalcemia, usually suggest a malignancy-associated hypercalcemic syndrome. The measurement of PTH-related protein, a tumor product that mimics certain action of PTH, is useful only in selected cases. The role of biochemical markers of bone turnover for predicting metastatic bone disease, and monitoring bone metabolic changes, and their usefulness as a predictive mean of the likelihood of bone loss or fractures risk is still unclear.

  13. Calcium signalling silencing in atrial fibrillation. (United States)

    Greiser, Maura


    Subcellular calcium signalling silencing is a novel and distinct cellular and molecular adaptive response to rapid cardiac activation. Calcium signalling silencing develops during short-term sustained rapid atrial activation as seen clinically during paroxysmal atrial fibrillation (AF). It is the first 'anti-arrhythmic' adaptive response in the setting of AF and appears to counteract the maladaptive changes that lead to intracellular Ca(2+) signalling instability and Ca(2+) -based arrhythmogenicity. Calcium signalling silencing results in a failed propagation of the [Ca(2+) ]i signal to the myocyte centre both in patients with AF and in a rabbit model. This adaptive mechanism leads to a substantial reduction in the expression levels of calcium release channels (ryanodine receptors, RyR2) in the sarcoplasmic reticulum, and the frequency of Ca(2+) sparks and arrhythmogenic Ca(2+) waves remains low. Less Ca(2+) release per [Ca(2+) ]i transient, increased fast Ca(2+) buffering strength, shortened action potentials and reduced L-type Ca(2+) current contribute to a substantial reduction of intracellular [Na(+) ]. These features of Ca(2+) signalling silencing are distinct and in contrast to the changes attributed to Ca(2+) -based arrhythmogenicity. Some features of Ca(2+) signalling silencing prevail in human AF suggesting that the Ca(2+) signalling 'phenotype' in AF is a sum of Ca(2+) stabilizing (Ca(2+) signalling silencing) and Ca(2+) destabilizing (arrhythmogenic unstable Ca(2+) signalling) factors. Calcium signalling silencing is a part of the mechanisms that contribute to the natural progression of AF and may limit the role of Ca(2+) -based arrhythmogenicity after the onset of AF. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

  14. Direct regulation of cytochrome c oxidase by calcium ions.

    Directory of Open Access Journals (Sweden)

    Tatiana Vygodina

    Full Text Available Cytochrome c oxidase from bovine heart binds Ca(2+ reversibly at a specific Cation Binding Site located near the outer face of the mitochondrial membrane. Ca(2+ shifts the absorption spectrum of heme a, which allowed previously to determine the kinetics and equilibrium characteristics of the binding. However, no effect of Ca(2+ on the functional characteristics of cytochrome oxidase was revealed earlier. Here we report that Ca(2+ inhibits cytochrome oxidase activity of isolated bovine heart enzyme by 50-60% with Ki of ∼1 µM, close to Kd of calcium binding with the oxidase determined spectrophotometrically. The inhibition is observed only at low, but physiologically relevant, turnover rates of the enzyme (∼10 s(-1 or less. No inhibitory effect of Ca(2+ is observed under conventional conditions of cytochrome c oxidase activity assays (turnover number >100 s(-1 at pH 8, which may explain why the effect was not noticed earlier. The inhibition is specific for Ca(2+ and is reversed by EGTA. Na(+ ions that compete with Ca(2+ for binding with the Cation Binding Site, do not affect significantly activity of the enzyme but counteract the inhibitory effect of Ca(2+. The Ca(2+-induced inhibition of cytochrome c oxidase is observed also with the uncoupled mitochondria from several rat tissues. At the same time, calcium ions do not inhibit activity of the homologous bacterial cytochrome oxidases. Possible mechanisms of the inhibition are discussed as well as potential physiological role of Ca(2+ binding with cytochrome oxidase. Ca(2+- binding at the Cation Binding Site is proposed to inhibit proton-transfer through the exit part of the proton conducting pathway H in the mammalian oxidases.


    NARCIS (Netherlands)



    The bandgap of solid C60 is found to be 2.3 +/- 0.1 eV. The on-site molecular C60 Coulomb interaction (U) as determined from the KVV C60 Auger spectrum is found to be 1.6 +/- .2 eV. This value of U is shown to be consistent with Frenkel type molecular excitons in the 1.5 - 2 eV range. These results

  16. Correlation Effects in Solid C60

    NARCIS (Netherlands)

    Lof, R.W.; Veenendaal, M.A. van; Heessels, A.; Jonkman, H.T.; Sawatzky, G.A.; Koopmans, H.


    The bandgap of solid C60 is found to be 2.3 ± 0.1 eV. The on-site molecular C60 Coulomb interaction (U) as determined from the KVV C60 Auger spectrum is found to be 1.6 ± .2 eV. This value of U is shown to be consistent with Frenkel type molecular excitons in the 1.5 - 2 eV range. These results lead

  17. 38 CFR 60.5 - Travel. (United States)


    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Travel. 60.5 Section 60.5... TEMPORARY LODGING § 60.5 Travel. As a condition for receiving temporary lodging under this part, a veteran must be required to travel either 50 or more miles, or at least two hours from his or her home to the...

  18. Dietary calcium intake and Renin Angiotensin System polymorphisms alter the blood pressure response to aerobic exercise: a randomized control design

    Directory of Open Access Journals (Sweden)

    Tsongalis Gregory J


    Full Text Available Abstract Background Dietary calcium intake and the renin angiotensin system (RAS regulate blood pressure (BP by modulating calcium homeostasis. Despite similar BP regulatory effects, the influence of dietary calcium intake alone and combined with RAS polymorphisms on the BP response following acute aerobic exercise (i.e., postexercise hypotension has not been studied. Thus, we examined the effect of dietary calcium intake and selected RAS polymorphisms on postexercise hypotension. Methods Subjects were men (n = 50, 43.8 ± 1.3 yr with high BP (145.3 ± 1.5/85.9 ± 1.1 mm Hg. They completed three experiments: non-exercise control and two cycle bouts at 40% and 60% of maximal oxygen consumption (VO2max. Subjects provided 3 d food records on five protocol-specific occasions. Dietary calcium intake was averaged and categorized as low (1R A/C were analyzed with molecular methods. Genotypes were reduced from three to two: ACE II/ID and ACE DD; or AT1R AA and AT1R CC/AC. Repeated measure ANCOVA tested if BP differed among experiments, dietary calcium intake level and RAS polymorphisms. Results Systolic BP (SBP decreased 6 mm Hg after 40% and 60% VO2max compared to non-exercise control for 10 h with LowCa (p 2max versus non-exercise control for 10 h among ACE II/ID (6 mm Hg and AT1R AA (8 mm Hg; and by 8 mm Hg after 40% VO2max among ACE DD and AT1R CC/CA (p 2max compared to non-exercise control for 10 h (p 2max (p ≥ 0.05. Conclusion SBP decreased after exercise compared to non-exercise control among men with low but not high dietary calcium intake. Dietary calcium intake interacted with the ACE I/D and AT1R A/C polymorphisms to further modulate postexercise hypotension. Interactions among dietary calcium intake, exercise intensity and RAS polymorphisms account for some of the variability in the BP response to exercise.

  19. Food labeling: health claims; calcium and osteoporosis, and calcium, vitamin D, and osteoporosis. Final rule. (United States)


    The Food and Drug Administration (FDA) is amending its labeling regulation authorizing a health claim on the relationship between calcium and a reduced risk of osteoporosis to include vitamin D so that, in addition to the claim for calcium and osteoporosis, an additional claim can be made for calcium and vitamin D and osteoporosis; eliminate the requirement that the claim list sex, race, and age as specific risk factors for the development of osteoporosis; eliminate the requirement that the claim does not state or imply that the risk of osteoporosis is equally applicable to the general U.S. population, and that the claim identify the populations at particular risk for the development of osteoporosis; eliminate the requirement that the claim identify the mechanism by which calcium reduces the risk of osteoporosis and instead make it optional; eliminate the requirement that the claim include a statement that a total dietary intake greater than 200 percent of the recommended daily intake (2,000 milligrams (mg) of calcium) has no further benefit to bone health when the food contains 400 mg or more of calcium per reference amount customarily consumed or per total daily recommended supplement intake; and allow reference for the need of physical activity in either of the health claims to be optional rather then required. This final rule is, in part, in response to a health claim petition submitted by The Beverage Institute for Health and Wellness, LLC.

  20. Calcium and calcium magnesium carbonate specimens submitted as urinary tract stones. (United States)

    Gault, M H; Chafe, L; Longerich, L; Mason, R A


    Of 8,129 specimens submitted as urinary stones from 6,095 patients, 67 from 15 patients were predominantly calcium carbonate or calcium magnesium carbonate (dolomite) by infrared analysis. Detailed study of 1 man and 4 women who submitted 3 or more such specimens showed that all were of aragonite calcium carbonate crystal form in 2 women and all calcite in the man. All 3 patients had a long history of nephrolithiasis preceding submission of calcium carbonate stones. There was frequent and often painful spontaneous passage of many small stones. Medullary sponge kidney was reported in 2 patients. Specimens submitted by the other 2 women included dolomite and quartz artifacts. Of the other 10 patients 4 had calcite and 1 had aragonite (possibly true stones). Five patients had artifacts with dolomite in 3 and mixed specimens in 2. True calcium carbonate kidney stones and calcium carbonate artifacts may be difficult to distinguish, and dolomite and quartz artifacts may require x-ray diffraction for clear-cut diagnosis.