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Sample records for calcium nitrate inhibitor

  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. The effect of farmyard manure and calcium ammonium nitrate on ...

    African Journals Online (AJOL)

    The effect of farmyard manure and calcium ammonium nitrate on vegetative growth, leaf yield and nutritive quality of Cleome gynadra (Cat Whiskers) in Keiyo District, ... extension workers and farmers, are receiving renewed interest as a possible intervention to food insecurity and malnutrition among resource-poor farmers.

  3. Effects of Calcium Lignosulfonate and Silicic Acid on Ammonium Nitrate Degradation

    Directory of Open Access Journals (Sweden)

    Ahmet Ozan Gezerman

    2014-01-01

    Full Text Available Ammonium nitrate salts are the most commonly used nitrogenous fertilizers in industry. However, storage of ammonium nitrate is problematic, since its initial properties can decline because of environmental factors, leading to large economic losses. In this study, in order to prevent the caking and degradation of ammonium nitrate, an alternative composition with additional calcium lignosulfonate and silicic acid was studied. The resulting fertilizer was analyzed by screening analysis, ion chromatography, and electron microscopy methods.

  4. Sandia National Laboratories Small-Scale Sensitivity Testing (SSST) Report: Calcium Nitrate Mixtures with Various Fuels.

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Jason Joe [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2014-07-01

    Based upon the presented sensitivity data for the examined calcium nitrate mixtures using sugar and sawdust, contact handling/mixing of these materials does not present hazards greater than those occurring during handling of dry PETN powder. The aluminized calcium nitrate mixtures present a known ESD fire hazard due to the fine aluminum powder fuel. These mixtures may yet present an ESD explosion hazard, though this has not been investigated at this time. The detonability of these mixtures will be investigated during Phase III testing.

  5. In situ field measurements of ammonia volatilization from urea and calcium ammonium nitrate applied to grassland

    NARCIS (Netherlands)

    Velthof, G.L.; Oenema, O.; Postmus, J.; Prins, W.H.

    1990-01-01

    Ammonia (NH3) volatilization from urea and calcium ammonium nitrate (CAN) broadcast to permanent grassland on a clay soil was measured in-situ, using a system of wind-tunnels. When CAN was applied virtually no NH3 volatilized. More than half of the 1

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  7. Synthesis of porous poly(acrylamide hydrogels using calcium carbonate and its application for slow release of potassium nitrate

    Directory of Open Access Journals (Sweden)

    2009-05-01

    Full Text Available Porous poly(acrylamide was synthesized using calcium carbonate microparticles and subsequent acid treatment to remove the calcium carbonate. Methylenebisacrylamide and ammonium persulfate/sodium metabisulfite were used as crosslinking agent and redox initiator, respectively. The porous structure of resulted hydrogels was confirmed using SEM micrographs. The effect of methylenebisacrylamide concentration and calcium carbonate amount on the swelling of the hydrogels was investigated. The results showed that the effect of methylenebisacrylamide and calcium carbonate variables on the swelling is reverse. The hydrogels were subsequently utilized for the loading of potassium nitrate. Potassium nitrate as active agent was loaded into hydrogels and subsequently the release of this active agent was investigated. In these series of investigation, the effect of content of loading, methylenebisacrylamide and calcium carbonate amount on the release of potassium nitrate from hydrogels was investigated.

  8. Aromatase inhibitors and calcium absorption in early stage breast cancer.

    Science.gov (United States)

    Tevaarwerk, Amye; Burkard, Mark E; Wisinski, Kari B; Shafer, Martin M; Davis, Lisa A; Gogineni, Jyothi; Crone, Elizabeth; Hansen, Karen E

    2012-07-01

    To investigate the effect of aromatase inhibitors (AI) on intestinal calcium absorption, measured using the gold-standard dual stable calcium isotope method. In this pilot study, we recruited 10 postmenopausal women with hormone receptor-positive breast cancer who planned to initiate AI therapy; women receiving chemotherapy were excluded. Women completed two 24 h inpatient calcium absorption study visits, the first prior to AI therapy and the second at least 6 weeks following onset of AI therapy. We calculated total fractional calcium absorption (TFCA) using the dose-corrected fractional recovery of two stable isotopes from 24 h urine collections. Ten postmenopausal women (mean±SD age, 66±7 years; 25(OH)D 40±7 ng/mL, and total calcium intake of 1,714±640 mg/day) exhibited no change in TFCA related to AI therapy (0.155±0.042 prior to and 0.160±0.064 following AI therapy, p=1.0). Subjects exhibited a surprisingly small decline in serum estradiol levels with AI therapy that was not statistically significant. However, there was a significant correlation between duration of AI therapy and the decline in serum estradiol levels (r=-0.65, p=0.040). In this pilot study, AI therapy did not decrease TFCA. Women with early stage breast cancer exhibited an unexpectedly low TFCA, most likely due to their high calcium intake. The null effect of AI therapy on TFCA might relate to the brief duration of AI therapy, the minimal effect of AI therapy on estradiol levels, subjects' high calcium intake or excellent vitamin D status.

  9. Elemental source attribution signatures for calcium ammonium nitrate (CAN) fertilizers used in homemade explosives

    Energy Technology Data Exchange (ETDEWEB)

    Fraga, Carlos G.; Mitroshkov, Alexander V.; Mirjankar, Nikhil S.; Dockendorff, Brian P.; Melville, Angie M.

    2017-11-01

    Calcium ammonium nitrate (CAN) is a widely available fertilizer composed of ammonium nitrate mixed with some form of calcium carbonate such as limestone or dolomite. CAN is also frequently used to make homemade explosives. The potential of using elemental profiling and chemometrics to match both pristine and reprocessed CAN fertilizers to their factories for use in future forensic investigations was examined. Inductively coupled plasma-mass spectrometry (ICP-MS) analysis was performed on 64 elements in 125 samples from 11 CAN stocks from 6 different CAN factories. Fisher ratio, degree-of-class-separation, and partial least squares discriminant analysis (PLSDA) were used to develop a model using the concentrations of Na, V, Mn, Cu, Ga, Sr, Ba and U to classify a validation set of CAN samples into 5 factory groups; one group was two factories from the same fertilizer company. In terms of the pristine CAN samples, i.e., unadulterated prills, 64% of the test samples were matched to their correct factory group with zero false positives. The same PLSDA model was used to correctly match 100% of the CAN samples that were reprocessed by crushing and mixing the CAN with powdered sugar. In the case of crushed CAN samples mixed with aluminum powder, correct matches were made for zero to 100% of the samples depending on the factory the CAN originated. Remarkably, for one factory, 100% of the ammonium nitrate samples that were extracted from CAN using tap or bottled water were matched to the correct CAN factory group. Lastly, the water-insoluble (calcium carbonate) portions of CAN provided a greater degree of discrimination between factories than the water-soluble portions of CAN. In summary, this work illustrates that sourcing unadulterated CAN fertilizer can potentially be done with high frequency and high confidence using elemental profiling and chemometrics while the sourcing of reprocessed CAN is dependent on how much an adulterant alters the recovered elemental profile of

  10. Effect of lithium nitrate and calcium nitrate composition on the thermal properties of quaternary molten salts mixture for heat transfer application

    Science.gov (United States)

    Ahmad, Nuratikah Nadhirah Binti; Yunos, Nursyafiqah Binti; Muhammad, Wan Nur Azrina Binti Wan; Mohamad, Md Nor Anuar Bin; Yusof, Farazila Binti

    2017-10-01

    Mixed molten salt is considered as a promising medium for both heat transfer and energy storage in thermal power because of its many advantages such as low the melting point, large heat capacity, good thermal stability and low cost. In order to determine the thermal properties of the molten salt, the nitrate quaternary mixture of the molten salt are prepared based on the different composition of the lithium nitrate and calcium nitrate. The other salts in the mixture are potassium nitrate and sodium nitrate. Mixture of molten salts were heated in furnace at 150°C for 4 hours and increased the temperature to 400°C for 8 hours for homogenize the salt mixture. Then, decreased the temperature to 115°C for an hour. The melting point and thermal stability of the mixture was determined by using thermogravimetric analysis [TGA] while the heat capacity was determined by using differential scanning calorimetry [DSC]. The lowest melting point using different composition of lithium nitrate, 10wt%NaNO3, 4Owt%KNO3, 20wt%Ca[NO3]2, 30wt%LiNO3 which is 97.1°C while the heat capacity is 6.33 J/g°C. For the experiment using various composition of calcium nitrate, the lowest melting point is from 14wt% NaNO3 + 48wt% KNO3 + 13wt% LiNO3 + 25wt% Ca[NO3]2 which is 111.7°C and the heat capacity is 2.06 J/g °C. From the result, the addition of lithium nitrate in the quaternary molten salts give more effect to the reduction of melting point value but higher heat capacity.

  11. Efficacy of Mixtures of Magnesium, Citrate and Phytate as Calcium Oxalate Crystallization Inhibitors in Urine.

    Science.gov (United States)

    Grases, Felix; Rodriguez, Adrian; Costa-Bauza, Antonia

    2015-09-01

    The main aim of the current study was to evaluate the effectiveness of mixtures of magnesium, citrate and phytate as calcium oxalate crystallization inhibitors. A turbidimetric assay in synthetic urine was performed to obtain induction times for calcium oxalate crystallization in the absence and presence of different mixtures of inhibitors. The morphology of calcium oxalate crystals in the absence or presence of inhibitors and mixtures of the inhibitors was evaluated in 2 crystallization experiments at low and high calcium oxalate supersaturation. The crystals formed were examined using scanning electron microscopy. Examination of crystallization induction times revealed clear inhibitory effects of magnesium, citrate and phytate on calcium oxalate crystallization, supporting usefulness in the treatment and prevention of calcium oxalate nephrolithiasis. Significant synergistic effects between magnesium and phytate were observed. Scanning electron microscopy images revealed that phytate is a powerful crystal growth inhibitor of calcium oxalate, totally preventing the formation of trihydrate and monohydrate. In addition to crystallization inhibition capacity, citrate and magnesium avoided calcium oxalate crystallization by decreasing its supersaturation. The synergistic effect between magnesium and phytate on calcium oxalate crystallization suggests that a combination of these 2 compounds may be highly useful as antilithiasis therapy. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  12. Phase evolution during heat treatment of amorphous calcium phosphate derived from fast nitrate synthesis

    Directory of Open Access Journals (Sweden)

    Zoltan Z. Zyman

    2017-06-01

    Full Text Available The phase evolution in amorphous calcium phosphate (ACP, with a Ca/P ratio of 1 : 1, derived from the fast nitrate synthesis using different conditions, was studied in temperature range 20-980°C. ACP crystallized within 600-700°C and the phase composition depended on the synthesis duration. It was firstly revealed that for an extremely short synthesis (1min two metastable phases α′-CPP and α′-TCP of the high-temperature calcium pyrophosphate α-CPP and tricalcium phosphate α-TCP were crystallized. For a longer synthesis (5min, α′- CPP and minor β-CPP crystallized. The metastable phases gradually transformed to stable polymorphs β-CPP and β-TCP above 800°C, and a biphasic mixture β-CPP/β-TCP or β-CPP formed at 980°C. The crystallization of the metastable phases was attributed to the Ostwald step rule. A mechanism for the formation of TCP (Ca/P = 1.5 from ACP (Ca/P = 1 was proposed. The prepared powders of β-CPP/β-TCP, β-CPP or initial ACP were fine-grained and would have enhanced sinterability. Contribution to the densification was demonstrated due to the thermal transformation of the metastable polymorphs into stable phases having higher densities.

  13. Evidence of a Lead Metathesis Product from Calcium Hydroxyapatite Dissolution in Lead Nitrate Solution

    Directory of Open Access Journals (Sweden)

    Oratai Saisa-ard

    2014-01-01

    Full Text Available Calcium hydroxyapatite, CaHAp, synthesized by the precipitation method, was utilized to study the calcium-lead metathesis reaction on dissolution in a lead nitrate solution under reflux conditions to prepare larger lead hydroxyapatite, PbHAp, crystals from CaHAp. SEM images show development of crystalline PbHAp on the surfaces of CaHAp. The needle-like crystal morphology observed for PbHAp after 24 h reaction time developed into hexagonal-rod crystal morphology within 48 h reaction time. The largest PbHAp crystals obtained from 48 h reaction time have approximate size of 10 × 10 × 40 μm. Powder X-ray diffraction results show mixed phases of CaHAp and PbHAp due to difficulty in separating the PbHAp product from the CaHAp substrate. The PbHAp peaks observed after 24 h of reaction sharpen and increase in intensity after 48 h of reaction confirming that the PbHAp phase is the major product for the 48 h reaction time. EDX results of the crystalline products show high intensity Pb peaks with lead to phosphorous ratio (5 : 3 as expected for PbHAp. Lower intensity Ca peaks are also observed, consistent with incomplete coverage of the CaHAp growth substrate.

  14. Elemental source attribution signatures for calcium ammonium nitrate (CAN) fertilizers used in homemade explosives.

    Science.gov (United States)

    Fraga, Carlos G; Mitroshkov, Alexander V; Mirjankar, Nikhil S; Dockendorff, Brian P; Melville, Angie M

    2017-11-01

    Calcium ammonium nitrate (CAN) is a widely available fertilizer composed of ammonium nitrate (AN) mixed with some form of calcium carbonate such as limestone or dolomite. CAN is also frequently used to make homemade explosives. The potential of using elemental profiling and chemometrics to match both pristine and reprocessed CAN fertilizers to their factories of origin for use in future forensic investigations was examined. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine the concentrations of 64 elements in 125 samples from 11 CAN stocks from 6 different CAN factories. Using Fisher ratio and degree-of-class-separation, the elements Na, V, Mn, Cu, Ga, Sr, Ba and U were selected for classification of the CAN samples into 5 factory groups; one group was two factories from the same fertilizer company. Partial least squares discriminant analysis (PLSDA) was used to develop a classification model which was tested on a separate set of samples. The test set included samples that were analyzed at a different time period and samples from factory stocks that were not part of the training set. For pristine CAN samples, i.e., unadulterated prills, 73% of the test samples were matched to their correct factory group with the remaining 27% undetermined using strict classification. The same PLSDA model was used to correctly match all CAN samples that were reprocessed by mixing with powdered sugar. For CAN samples that were reprocessed by mixing with aluminum or by extraction of AN with tap or bottled water, correct classification was observed for one factory group, but source matching was confounded with adulterant interference for two other factories. The elemental signatures of the water-insoluble (calcium carbonate) portions of CAN provided a greater degree of discrimination between factories than the water-soluble portions of CAN. In summary, this work illustrates the strong potential for matching unadulterated CAN fertilizer samples to their

  15. Feed intake, growth, and body and carcass attributes of feedlot steers supplemented with two levels of calcium nitrate or urea.

    Science.gov (United States)

    Hegarty, R S; Miller, J; Oelbrandt, N; Li, L; Luijben, J P M; Robinson, D L; Nolan, J V; Perdok, H B

    2016-12-01

    Nitrate supplementation has been shown to be effective in reducing enteric methane emission from ruminants, but there have been few large-scale studies assessing the effects of level of nitrate supplementation on feed intake, animal growth, or carcass and meat quality attributes of beef cattle. A feedlot study was conducted to assess the effects of supplementing 0.25 or 0.45% NPN in dietary DM as either urea (Ur) or calcium nitrate (CaN) on DMI, ADG, G:F, and carcass attributes of feedlot steers ( = 383). The levels of NPN inclusion were selected as those at which nitrate has previously achieved measurable mitigation of enteric methane. The higher level of NPN inclusion reduced ADG as did replacement of Ur with CaN ( nitrate-supplemented cattle to have a slower rate of eating (g DMI/min) than Ur-supplemented cattle. When adjusted for BW, neither NPN source nor inclusion level affected cross-sectional area of the LM or fatness measured on the live animal. Similarly, there were no significant main effects of treatments on dressing percentage or fat depth or muscling attributes of the carcass after adjustment for HCW ( > 0.05). Analysis of composited meat samples showed no detectable nitrates or nitrosamines in raw or cooked meat, and the level of nitrate detected in meat from nitrate-supplemented cattle was no higher than for Ur-fed cattle ( > 0.05). We conclude that increasing NPN inclusion from 0.25 to 0.45% NPN in dietary DM and replacing Ur with CaN decreased ADG in feedlot cattle without improving G:F.

  16. Comparative evaluation of a dentifrice containing calcium sodium phosphosilicate to a dentifrice containing potassium nitrate for dentinal hypersensitivity: A clinical study

    National Research Council Canada - National Science Library

    Satyapal, Tanya; Mali, Rohini; Mali, Amita; Patil, Vishakha

    2014-01-01

    .... This study was designed to assess the efficacy of a new toothpaste containing 5% calcium sodium phosphosilicate for the treatment of dentinal hypersensitivity and also compare it with 5% potassium nitrate...

  17. Dietary calcium supplementation enhances efficacy but also toxicity of EGFR inhibitor therapy for colon cancer.

    Science.gov (United States)

    Rinella, Erica S; Bankaitis, Eric D; Threadgill, David W

    2012-02-01

    The inverse correlation between levels of dietary calcium and colorectal cancer (CRC) incidence has been extensively investigated. However, the impact of supplemental calcium on cancer therapy remains unknown. We used four models of CRC, Caco-2 and HCT116 human cancer cell lines and Apc (Min/+) and azoxymethane carcinogen-induced mouse models, to investigate the impact of a western-style diet low in calcium (0.05%) vs. a similar diet but supplemented with calcium (5%) on therapeutic targeting of the epidermal growth factor receptor (EGFR). We found that calcium supplementation combined with pharmacologic blockade of EGFR results in an additive effect on tumor growth inhibition in all models. Unexpectedly, the combined use of dietary calcium supplementation and EGFR inhibitors also resulted in elevated toxicity suggesting that careful consideration be given when combining dietary supplements with prescribed cancer therapies.

  18. Bax inhibitor 1, a modulator of calcium homeostasis, confers affective resilience

    OpenAIRE

    Hunsberger, Joshua G.; Machado-Vieira, Rodrigo; Austin, Daniel R.; Zarate, Carlos; Chuang, De-Maw; Chen, Guang; Reed, John C.; Manji, Husseini K.

    2011-01-01

    The endoplamic reticulum (ER) is a critical site for intracellular calcium storage as well as protein synthesis, folding, and trafficking. Disruption of these processes is gaining support for contributing to heritable vulnerability of certain diseases. Here, we investigated Bax inhibitor 1 (BI-1), an anti-apoptotic protein that primarily resides in the ER and associates with B-cell lymphoma 2 (Bcl-2) and Bcl-XL, as an affective resiliency factor through its modulation of calcium homeostasis. ...

  19. Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

    Science.gov (United States)

    Lee, J. S.; Mulkey, T. J.; Evans, M. L.

    1984-01-01

    Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

  20. Bax inhibitor 1, a modulator of calcium homeostasis, confers affective resilience.

    Science.gov (United States)

    Hunsberger, Joshua G; Machado-Vieira, Rodrigo; Austin, Daniel R; Zarate, Carlos; Chuang, De-Maw; Chen, Guang; Reed, John C; Manji, Husseini K

    2011-07-27

    The endoplasmic reticulum (ER) is a critical site for intracellular calcium storage as well as protein synthesis, folding, and trafficking. Disruption of these processes is gaining support for contributing to heritable vulnerability of certain diseases. Here, we investigated Bax inhibitor 1 (BI-1), an anti-apoptotic protein that primarily resides in the ER and associates with B-cell lymphoma 2 (Bcl-2) and Bcl-XL, as an affective resiliency factor through its modulation of calcium homeostasis. We found that transgenic (TG) mice with BI-1 reinforced expression, via the neuronal specific enolase promoter, showed protection against the learned helplessness (LH) paradigm, an animal model to test stress coping. TG mice were also protected against anhedonia following both serotonin and catecholamine depletion as measured in two different models, the female urine sniffing test and the saccharine preference test. In addition, we used primary mouse cortical cultures to explore the ability of BI-1 to influence calcium homeostasis under basal conditions and also following challenge with thapsigargin (THPS), an inhibitor of sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA) that disrupts calcium homeostasis. TG neurons showed decreased basal cytosolic calcium levels and decreased Ca(2+) cytosolic accumulation following challenge with THPS as compared to WT neuronal cultures. Together, these data suggest that BI-1, through its actions on calcium homeostasis, may confer affective resiliency in multiple animal models of depression and anhedonia. Published by Elsevier B.V.

  1. Does calcium in drinking water modify the association between nitrate in drinking water and risk of death from colon cancer?

    Science.gov (United States)

    Chiu, Hui-Fen; Tsai, Shang-Shyue; Chen, Pei-Shih; Wu, Trong-Neng; Yang, Chun-Yuh

    2011-09-01

    The objective of this study was to explore whether calcium (Ca) levels in drinking water modified the effects of nitrate on colon cancer risk. A matched case-control study was used to investigate the relationship between the risk of death from colon cancer and exposure to nitrate in drinking water in Taiwan. All colon cancer deaths of Taiwan residents from 2003 through 2007 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cases by gender, year of birth and year of death. Information on the levels of nitrate-nitrogen (NO(3)-N) and Ca in drinking water have been collected from Taiwan Water Supply Corporation (TWSC). The municipality of residence for cases and controls was assumed to be the source of the subject's NO(3)-N and Ca exposure via drinking water. We observed evidence of an interaction between drinking water NO(3)-N and Ca intake via drinking water. This is the first study to report effect modification by Ca intake from drinking water on the association between NO(3)-N exposure and risk of colon cancer mortality.

  2. Rapid, high-temperature, field test method for evaluation of geothermal calcium carbonate scale inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G.

    1986-09-01

    A new test method is described that allows the rapid field testing of calcium carbonate scale inhibitors at 500/sup 0/F (260/sup 0/C). The method evolved from use of a full-flow test loop on a well with a mass flow rate of about 1 x 10/sup 6/ lbm/hr (126 kg/s). It is a simple, effective way to evaluate the effectiveness of inhibitors under field conditions. Five commercial formulations were chosen for field evaluation on the basis of nonflowing, laboratory screening tests at 500/sup 0/F (260/sup 0/C). Four of these formulations from different suppliers controlled calcium carbonate scale deposition as measured by the test method. Two of these could dislodge recently deposited scale that had not age-hardened. Performance-profile diagrams, which were measured for these four effective inhibitors, show the concentration interrelationship between brine calcium and inhibitor concentrations at which the formulations will and will not stop scale formation in the test apparatus. With these diagrams, one formulation was chosen for testing on the full-flow brine line. The composition was tested for 6 weeks and showed a dramatic decrease in the scaling occurring at the flow-control valve. This scaling was about to force a shutdown of a major, long-term flow test being done for reservoir economic evaluations. The inhibitor stopped the scaling, and the test was performed without interruption.

  3. Nitrate Reduction in Canned Apples and Pears Using Calcium Hydrogen Phosphate (CaHPO4

    Directory of Open Access Journals (Sweden)

    Parisa Ziarati*

    2017-09-01

    Full Text Available Background: The aim of this study was to introduce a new and economical method for reduction of nitrate content in canned apples and pears. Methods: The nitrate content was determined before and after treatment with CaHPO4 ranging from 0.01% to 0.1% using spectroscopic method in 2015 in Pharmaceutical Sciences Research Center, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran- Iran. The effect of treatment time at three different time points (30, 60, 90 min was determined. Sensory evaluation was performed using five-point hedonic scales. Results: Nitrate content in fresh fruit is significantly (P<0.05 lower than canned products; this may be explained by the effect of water for washing fruits during processing. The mean value of nitrate in canned apples were significantly (P<0.05 higher compared to the canned pears; this may be related to the type of fruits and its texture and composition. Nitrate content of canned apples and pears were decreased from 233.24±24.90 to 128.80±0.423 and 195.11±20.32 to 118.804±0.634 mg/kg, respectively. Different concentration of CaHPO4 did not influence sensory attributes of canned apples while overall acceptance of canned pears decreased only in 0.1% CaHPO4 (P<0.05. The most efficient time for treating by CaHPO4 was 90 min, but the most practical one is recommended 30 min. Addition of CaHPO4 did not change pH of canned samples. Conclusion: Application of CaHPO4 is suggested as a novel, safe and economical method for removal of nitrate in canned products.

  4. Ceria nanoparticles vis-à-vis cerium nitrate as corrosion inhibitors for silica-alumina hybrid sol-gel coating

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmi, R.V. [Surface Engineering Division, Council of Scientific and Industrial Research – National Aerospace Laboratories, HAL Airport Road, Kodihalli, Bengaluru 560017 (India); Aruna, S.T., E-mail: staruna194@gmail.com [Surface Engineering Division, Council of Scientific and Industrial Research – National Aerospace Laboratories, HAL Airport Road, Kodihalli, Bengaluru 560017 (India); Sampath, S. [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bengaluru 560012 (India)

    2017-01-30

    Highlights: • Corrosion protection efficiency comparison of ceria nanoparticles and cerium nitrate. • Silica-alumina hybrid coating exhibited good barrier protection. • Detailed XPS study confirm the hybrid structure and presence of Ce species in coating. • Loss of cerium ions not prevalent in ceria doped coating unlike that of cerium nitrate. • Ceria increased the coating integrity, corrosion inhibition and barrier protection. - Abstract: The present work provides a comparative study on the corrosion protection efficiency of defect free sol-gel hybrid coating containing ceria nanoparticles and cerium nitrate ions as corrosion inhibitors. Less explored organically modified alumina-silica hybrid sol-gel coatings are synthesized from 3-glycidoxypropyltrimethoxysilane and aluminium-tri-sec-butoxide. The microemulsion derived nanoparticles and the hybrid coatings are characterized and compared with coatings containing cerium nitrate. Corrosion inhibiting capability is assessed using electrochemical impedance spectroscopy. Scanning Kelvin probe measurements are also conducted on the coatings for identifying the apparent corrosion prone regions. Detailed X-ray photoelectron spectroscopy (XPS) analysis is carried out to comprehend the bonding and corrosion protection rendered by the hybrid coatings.

  5. Protein arginine deiminase 2 binds calcium in an ordered fashion: implications for inhibitor design.

    Science.gov (United States)

    Slade, Daniel J; Fang, Pengfei; Dreyton, Christina J; Zhang, Ying; Fuhrmann, Jakob; Rempel, Don; Bax, Benjamin D; Coonrod, Scott A; Lewis, Huw D; Guo, Min; Gross, Michael L; Thompson, Paul R

    2015-04-17

    Protein arginine deiminases (PADs) are calcium-dependent histone-modifying enzymes whose activity is dysregulated in inflammatory diseases and cancer. PAD2 functions as an Estrogen Receptor (ER) coactivator in breast cancer cells via the citrullination of histone tail arginine residues at ER binding sites. Although an attractive therapeutic target, the mechanisms that regulate PAD2 activity are largely unknown, especially the detailed role of how calcium facilitates enzyme activation. To gain insights into these regulatory processes, we determined the first structures of PAD2 (27 in total), and through calcium-titrations by X-ray crystallography, determined the order of binding and affinity for the six calcium ions that bind and activate this enzyme. These structures also identified several PAD2 regulatory elements, including a calcium switch that controls proper positioning of the catalytic cysteine residue, and a novel active site shielding mechanism. Additional biochemical and mass-spectrometry-based hydrogen/deuterium exchange studies support these structural findings. The identification of multiple intermediate calcium-bound structures along the PAD2 activation pathway provides critical insights that will aid the development of allosteric inhibitors targeting the PADs.

  6. Heat capacity and density of solutions of calcium and cadmium nitrates in N-methylpyrrolidone at 298.15 K

    Science.gov (United States)

    Novikov, A. N.; Rassokhina, L. Yu.

    2013-08-01

    The heat capacity and density of solutions of calcium and cadmium nitrates in N-methylpyrrolidone (MP) at 298.15 K are studied by calorimetry and densimetry. The obtained data are discussed in relation to certain features of solvation and complex formation in solutions of these salts. The standard partial molar heat capacities and volumes (overline {C_{p^2 }^0 } and overline {V_2^0 }) of the electrolytes in MP are calculated. The standard heat capacities overline {C_{p^i }^0 } and volumes overline {V_i^0 } of Ca2+ and Cd2+ ions in MP at 298.15 K were determined, along with the contribution from specific interactions to the values of overline {C_{p^i }^0 } and overline {V_i^0 } of Cd2+ ions in MP solution.

  7. Measuring calcium, potassium, and nitrate in plant nutrient solutions using ion-selective electrodes in hydroponic greenhouse of some vegetables.

    Science.gov (United States)

    Vardar, Gökay; Altıkatoğlu, Melda; Ortaç, Deniz; Cemek, Mustafa; Işıldak, İbrahim

    2015-01-01

    Generally, the life cycle of plants depends on the uptake of essential nutrients in a balanced manner and on toxic elements being under a certain concentration. Lack of control of nutrient levels in nutrient solution can result in reduced plant growth and undesired conditions such as blossom-end rot. In this study, sensitivity and selectivity tests for various polyvinylchloride (PVC)-based ion-selective membranes were conducted to identify those suitable for measuring typical concentration ranges of macronutrients, that is, NO(3-), K(+), and Ca(2+), in hydroponic solutions. The sensitivity and selectivity of PVC-membrane-based ion-selective sensors prepared with tetradodecylammoniumnitrate for NO(3-), valinomycin for K(+), and Ca ionophore IV for Ca(2+) were found to be satisfactory for measuring NO(3-), K(+), and Ca(2+) ions in nutrient solutions over typical ranges of hydroponic concentrations. Potassium, calcium, and nitrate levels that were utilized by cucumber and tomato seedlings in the greenhouse were different. The findings show that tomato plants consumed less amounts of nitrate than cucumber plants over the first 2 months of their growth. We also found that the potassium intake was higher than other nutritional elements tested for all plants. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

  8. The effect of urea with urease inhibitors and urea on yield and nitrate content in potato tubers

    Directory of Open Access Journals (Sweden)

    Karel Drápal

    2013-01-01

    Full Text Available The three-year field trial was established on two localities – Žabčice and Valečov in 2010–2012. Seven variants of nitrogen fertilization in four replications have been involved in this experiment – 100% of urea (U, 80% of urea, 60% of urea, 100% of UreaStabil (US, 80% of UreaStabil and 60% of UreaStabil, whilst 100% corresponded to 90 kg N.ha−1 after subtracting the content of Nmin in the soil, and the control variant without fertilization by mineral nitrogen. The two varieties with different lengths of vegetation periods have been chosen for the experiment – the early variety Karin and the mid-early variety Red Anna. In all cases, samples for the yield and qualitative analyses have been taken according to the phenological phase – the beginning of physiological maturity. The obtained results show that the highest average yield has been achieved in the variant of 100% of urea – 40.95 t. ha−1, the yield of this variant was statistically significantly higher than the yield of the other variants of fertilization (P < 0.05. Variants treated by urea without the urease inhibitor reached an average yield of 37.62 t.ha−1. However, this yield was not statistically significantly higher when comparing to the urea with the urease inhibitor (P > 0.05. In regard to localities, a relatively high average yield (44.58 t.ha−1 has been achieved on a characteristically potato-growing locality Valečov. This yield was statistically significantly higher than the one attained on the Žabčice locality (P < 0.05. In respect to varieties, the mid-early variety Red Anna attained a higher average yield (39.65 t. ha−1. Likewise, this yield was statistically significantly higher than the one of the early variety Karin (P < 0.05. The best year was 2012, in which the average yield of 38.73 t.ha−1 was achieved. This yield was statistically significantly higher than the yield of the year 2010 (P < 0.05. As far as nitrates are concerned, the

  9. Regulation of NKG2D-ligand cell surface expression by intracellular calcium after HDAC-inhibitor treatment

    DEFF Research Database (Denmark)

    Jensen, Helle; Hagemann-Jensen, Michael Henrik; Lauridsen, Felicia Kathrine Bratt

    2013-01-01

    cell surface expression on melanoma cells and Jurkat T-cells. A NKG2D-dependent cytolytic assay and staining with a recombinant NKG2D-Fc fusion protein showed that calcium chelation impaired the functional ability of NKG2D-ligands induced by HDAC-inhibitor treatment. The HDAC-inhibitor induced cell......-cells. We further show that secretion and cell surface binding of the calcium-regulating protein galectin-1 is enhanced upon HDAC-inhibitor treatment of melanoma cells. However, binding of galectin-1 to cell surface glycoproteins was not critical for constitutive or HDAC-inhibitor induced MICA/B and ULBP2...

  10. Comparative evaluation of a dentifrice containing calcium sodium phosphosilicate to a dentifrice containing potassium nitrate for dentinal hypersensitivity: A clinical study

    Directory of Open Access Journals (Sweden)

    Tanya Satyapal

    2014-01-01

    Full Text Available Background: Calcium sodium phosphosilicate is a recently introduced desensitizing agent which acts by occluding the dentinal tubules and also resists acid decalcification. This study was designed to assess the efficacy of a new toothpaste containing 5% calcium sodium phosphosilicate for the treatment of dentinal hypersensitivity and also compare it with 5% potassium nitrate. Materials and Methods: Sixty patients with the chief complaint of dentinal hypersensitivity were enrolled and randomly divided into two groups. The visual analog scale (VAS scores were taken for water and air stimuli at baseline, 3 weeks after usage of the respective toothpaste, and 3 weeks after discontinuation of the respective toothpaste. Results: Both the groups showed reduction in hypersensitivity scores at 3 weeks and 6 weeks for air stimulus and cold water. The calcium sodium phosphosilicate group, however, showed significantly reduction in hypersensitivity compared to the potassium nitrate group at any time point for both measures of hypersensitivity. Conclusion: The 5% calcium sodium phosphosilicate group showed immense reduction in dentinal hypersensitivity symptoms. The 5% calcium sodium phosphosilicate showed prolonged effects even after discontinuation as compared to 5% potassium nitrate, due to its dentinal tubular occlusion property.

  11. Effects of a new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate and potassium leaching in two soils.

    Science.gov (United States)

    Wu, Shao-Fu; Wu, Liang-Huan; Shi, Qi-Wei; Wang, Zhong-Qiang; Chen, Xian-You; Li, Yong-Shan

    2007-01-01

    In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate (NO3(-)-N) and potassium (K) leaching in the sandy loam soil and clay loam soil. The results showed that DMPP with ammonium sulphate nitrate (ASN) ((NH4)2SO4 and NH4NO3) or urea could reduce NO3(-)-N leaching significantly, whereas ammonium (NH4(+)-N) leaching increased slightly. In case of total N (NO3(-)-N+NH4(+)-N), losses by leaching during the experimental period (40 d) were 37.93 mg (urea), 31.61 mg (urea+DMPP), 108.10 mg (ASN), 60.70 mg (ASN+DMPP) in the sandy loam soil, and 30.54 mg (urea), 21.05 mg (urea+DMPP), 37.86 mg (ASN), 31.09 mg (ASN+DMPP) in the clay loam soil, respectively. DMPP-amended soil led to the maintenance of relatively high levels of NH4(+)-N and low levels of NO3(-)-N in soil, and nitrification was slower. DMPP supplementation also resulted in less potassium leached, but the difference was not significant except the treatment of ASN and ASN+DMPP in the sandy loam soil. Above results indicate that DMPP is a good nitrification inhibitor, the efficiency of DMPP seems better in the sandy loam soil than in the clay loam soil and lasts longer.

  12. Effects of ethylene inhibitors, silver nitrate (AgNO3), cobalt chloride ...

    African Journals Online (AJOL)

    Significant increase in shoot regeneration, leaf chlorophyll content and rooting occurred when silver nitrate (AgNO3), cobalt chloride (CoCl2) or aminooxyacetic acid (AOA) were added to banana culture medium. The highest numbers of shoots per explants shoot length and leaf surface area was obtained when media were ...

  13. Inhibitors of arachidonate-regulated calcium channel signaling suppress triggered activity induced by the late sodium current.

    Science.gov (United States)

    Wolkowicz, Paul; Umeda, Patrick K; Sharifov, Oleg F; White, C Roger; Huang, Jian; Mahtani, Harry; Urthaler, Ferdinand

    2014-02-05

    Disturbances in myocyte calcium homeostasis are hypothesized to be one cause for cardiac arrhythmia. The full development of this hypothesis requires (i) the identification of all sources of arrhythmogenic calcium and (ii) an understanding of the mechanism(s) through which calcium initiates arrhythmia. To these ends we superfused rat left atria with the late sodium current activator type II Anemonia sulcata toxin (ATXII). This toxin prolonged atrial action potentials, induced early afterdepolarization, and provoked triggered activity. The calmodulin-dependent protein kinase II (CaMKII) inhibitor KN-93 (N-[2-[[[3-(4-chlorophenyl)-2-propenyl]methylamino]methyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulphon-amide) suppressed ATXII triggered activity but its inactive congener KN-92 (2-[N-(4-methoxy benzenesulfonyl)]amino-N-(4-chlorocinnamyl)-N-methylbenzylamine) did not. Neither drug affected normal atrial contractility. Calcium entry via L-type channels or calcium leakage from sarcoplasmic reticulum stores are not critical for this type of ectopy as neither verapamil ((RS)-2-(3,4-dimethoxyphenyl)-5-{[2-(3,4-dimethoxyphenyl)ethyl]-(methyl)amino}-2-prop-2-ylpentanenitrile) nor ryanodine affected ATXII triggered activity. By contrast, inhibitors of the voltage independent arachidonate-regulated calcium (ARC) channel and the store-operated calcium channel specifically suppressed ATXII triggered activity without normalizing action potentials or affecting atrial contractility. Inhibitors of cytosolic calcium-dependent phospholipase A2 also suppressed triggered activity suggesting that this lipase, which generates free arachidonate, plays a key role in ATXII ectopy. Thus, increased left atrial late sodium current appears to activate atrial Orai-linked ARC and store operated calcium channels, and these voltage-independent channels may be unexpected sources for the arrhythmogenic calcium that underlies triggered activity. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Calcium

    Science.gov (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 ...

  15. Neem seed oil: a potent nitrification inhibitor to control nitrate leaching after incorporation of crop residues

    OpenAIRE

    Opoku, A; Chaves, B; De Neve, Stefaan

    2014-01-01

    The effect of neem seed oil and neem leaf extract as organic nitrification inhibitors (NIs) on the accumulation of NH4+ and NO3-, and nitrification inhibition after incorporation of crop residue was investigated in an incubation experiment. Dicyandiamide (DCD) applications of 15 and 30 kg active ingredient ha(-1) were used as low and high doses of a synthetic NI. Soil samples were amended with 21 g kg(-1) cauliflower leaves and treated with NIs at a rate of 30 kg ha(-1) of neem seed oil, 60 k...

  16. Feed intake, growth, and body and carcass attributes of feedlot steers supplemented with two levels of calcium nitrate or urea

    NARCIS (Netherlands)

    Hegarty, R.S.; Miller, J.; Oelbrandt, N.; Li, L.; Luijben, J.P.M.; Robinson, D.L.; Nolan, J.V.; Perdok, H.B.

    2016-01-01

    Nitrate supplementation has been shown to be effective in reducing enteric methane emission from ruminants, but there have been few large-scale studies assessing the effects of level of nitrate supplementation on feed intake, animal growth, or carcass and meat quality attributes of beef cattle. A

  17. Comparative Behaviour of Nitrite and Nitrate for the Protection of Rebar Corrosion

    Science.gov (United States)

    Ahmad, Altaf; Kumar, Anil

    2017-10-01

    Corrosion of rebar steel due to environmental causes has been studied through various approaches, and among the protection techniques use of inhibitors has gained encouragement. Nitrites and nitrates of sodium have gained sufficient scientific coverage. Recently, nitrites and nitrates of calcium have been verified in some studies, which, however, needs further experimentation through different angles. Simple polarization technique has been utilized in the present study to compare inhibitive efficiency of these salts of sodium and calcium, which indicate that calcium salts are more efficient.

  18. Effective mitigation of nitrate leaching and nitrous oxide emissions in intensive vegetable production systems using a nitrification inhibitor, dicyandiamide

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Min; Sun, Xuecheng; Hu, Chengxiao; Tan, Qiling; Zhao, Changsheng [Huazhong Agricultural Univ., Wuhan (China). Key Lab. of Subtropical Agricultural Resources and Environment; Di, Hong J. [Lincoln Univ., Christchurch (New Zealand). Center for Soil and Environment Research

    2011-07-15

    Vegetable production is one of the most intensive agricultural systems with high rates of nitrogen (N) fertilizer use and irrigation, conditions conducive for nitrate (NO{sub 3}{sup -}) leaching, and nitrous oxide (N{sub 2}O) emissions. The objective of this study was to determine the effectiveness of a nitrification inhibitor, dicyandiamide (DCD), in decreasing NO{sub 3}{sup -} leaching and N{sub 2}O emissions in vegetable production systems. Twenty-four undisturbed soil monolith lysimeters (610 mm in diameter; 700 mm in depth; surface area, 0.29 m{sup 2}) with two different soils, Huangzongrang (alfisol) and Chaotu (fluvisols), were collected and installed in a field lysimeter facility in Central China under irrigated vegetable production conditions. Urea fertilizer was applied at 650 kg N ha{sup -1}, and DCD was applied at 10 kg ha{sup -1} to the lysimeters planted with three kinds of vegetables (capsicum, Capsicum annuum L.; amaranth, Amaranthus mangostanus L.; radish, Raphanus sativus L.). The results showed that DCD reduced NO3- leaching by 58.5% and 36.2% and N{sub 2}O emissions factor by 83.8% and 72.7% in the two soils. The average NO{sub 3}{sup -}-N concentration in the drainage water was decreased from 4.9 mg NL{sup -1} to 2.3 mg NL{sup -1} and from 4.4 mg NL{sup -1} to 3.3 mg NL{sup -1}, in the Huangzongrang and Chaotu soils, respectively. In addition to the environmental benefits, the use of DCD also increased the yields of capsicum and radish in alfisol soil significantly (P < 0.01); only the amaranth yield in fluvisol soil was declined (P < 0.01), and the other vegetables yields were not affected. Total N concentrations of the three vegetables were increased significantly (P < 0.01) with the application of DCD with urea compared with urea alone. These results showed that the nitrification inhibitor DCD has the potential to significantly reduce NO{sub 3}{sup -} leaching and N{sub 2}O emissions and to make vegetable farming more environmentally

  19. Calcium

    Science.gov (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 ...

  20. A FluoPol-ABPP PAD2 high-throughput screen identifies the first calcium site inhibitor targeting the PADs.

    Science.gov (United States)

    Lewallen, Daniel M; Bicker, Kevin L; Madoux, Franck; Chase, Peter; Anguish, Lynne; Coonrod, Scott; Hodder, Peter; Thompson, Paul R

    2014-04-18

    The protein arginine deiminases (PADs) catalyze the post-translational hydrolysis of peptidyl-arginine to form peptidyl-citrulline in a process termed deimination or citrullination. PADs likely play a role in the progression of a range of disease states because dysregulated PAD activity is observed in a host of inflammatory diseases and cancer. For example, recent studies have shown that PAD2 activates ERα target gene expression in breast cancer cells by citrullinating histone H3 at ER target promoters. To date, all known PAD inhibitors bind directly to the enzyme active site. PADs, however, also require calcium ions to drive a conformational change between the inactive apo-state and the fully active calcium bound holoenzyme, suggesting that it would be possible to identify inhibitors that bind the apoenzyme and prevent this conformational change. As such, we set out to develop a screen that can identify PAD2 inhibitors that bind to either the apo or calcium bound form of PAD2. Herein, we provide definitive proof of concept for this approach and report the first PAD inhibitor, ruthenium red (Ki of 17 μM), to preferentially bind the apoenzyme.

  1. Assessment of the acute toxicity of eutrophic sediments after the addition of calcium nitrate (Ibirité reservoir, Minas Gerais-SE Brazil: initial laboratory experiments

    Directory of Open Access Journals (Sweden)

    H. Janke

    Full Text Available This study evaluated the acute toxicity of sediment in a eutrophic reservoir after remediation with a calcium nitrate solution to retain phosphorus. The study involved microcosms of surface sediments and water from the sediment-water interface in the Ibirité reservoir. This reservoir, located in the vicinity of metropolitan Belo Horizonte (Minas Gerais, SE Brazil, is a water body that receives treated effluents from an oil refinery (REGAP-Petrobras, as well as high loads of untreated urban effluents from the city of Ibirité and surrounding areas and industrial effluents from a major industrial park. Incubation times of the treatment experiments were: t = 0, t = 5, t = 10, t = 25, t = 50, t = 85 and t = 135 days. One control microcosm and three treated microcosms were analysed in each time interval. Acute toxicity of water samples was assessed with Ceriodaphnia silvestrii Daday, 1902 and that of bulk sediment samples with Chironomus xanthus Rempel, 1939. Toxicity tests were carried out concomitantly with chemical analyses of dissolved inorganic nitrogen species (ammonia, nitrate and nitrite, sulfate and metals in the water samples of the microcosms. Acid volatile sulfides (AVS, simultaneously extracted metal (SEM and potentially bioavailable metal were analyzed in bulk sediment samples. Neither of the tested organisms showed toxicity in the control microcosm samples. The water column of the treated microcosm showed toxicity to C. silvestrii, starting at t = 10 days, while the sediment pore water toxicity started at t = 0 day. However, toxicity was found to decline from t = 85 days to t = 135 days. Sediments showed toxicity to C. xanthus during the entire experiment, except at the longest incubation time (t = 135 days. The overall results indicate that nitrate, which reached concentrations exceeding 1,200 mg N-NO3- L-1 in the sediment pore water of the treated microcosms, was most probably responsible for the toxicity of the samples. Although

  2. Exploring NMR ensembles of calcium binding proteins: Perspectives to design inhibitors of protein-protein interactions

    Directory of Open Access Journals (Sweden)

    Craescu Constantin T

    2011-05-01

    Full Text Available Abstract Background Disrupting protein-protein interactions by small organic molecules is nowadays a promising strategy employed to block protein targets involved in different pathologies. However, structural changes occurring at the binding interfaces make difficult drug discovery processes using structure-based drug design/virtual screening approaches. Here we focused on two homologous calcium binding proteins, calmodulin and human centrin 2, involved in different cellular functions via protein-protein interactions, and known to undergo important conformational changes upon ligand binding. Results In order to find suitable protein conformations of calmodulin and centrin for further structure-based drug design/virtual screening, we performed in silico structural/energetic analysis and molecular docking of terphenyl (a mimicking alpha-helical molecule known to inhibit protein-protein interactions of calmodulin into X-ray and NMR ensembles of calmodulin and centrin. We employed several scoring methods in order to find the best protein conformations. Our results show that docking on NMR structures of calmodulin and centrin can be very helpful to take into account conformational changes occurring at protein-protein interfaces. Conclusions NMR structures of protein-protein complexes nowadays available could efficiently be exploited for further structure-based drug design/virtual screening processes employed to design small molecule inhibitors of protein-protein interactions.

  3. Calcium

    Science.gov (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. Substituted imidazopyridazines are potent and selective inhibitors of Plasmodium falciparum calcium-dependent protein kinase 1 (PfCDPK1)

    OpenAIRE

    Chapman, Timothy M.; Osborne, Simon A.; Bouloc, Nathalie; Large, Jonathan M.; Wallace, Claire; Birchall, Kristian; Ansell, Keith H.; Jones, Hayley M.; Taylor, Debra; Clough, Barbara; Green, Judith L.; Holder, Anthony A.

    2013-01-01

    A series of imidazopyridazines which are potent inhibitors of Plasmodium falciparum calcium-dependent protein kinase 1 (PfCDPK1) was identified from a high-throughput screen against the isolated enzyme. Subsequent exploration of the SAR and optimisation has yielded leading members which show promising in vitro anti-parasite activity along with good in vitro ADME and selectivity against human kinases. Initial in vivo testing has revealed good oral bioavailability in a mouse PK study and modest...

  5. Inhibitors

    Science.gov (United States)

    ... and exercise, immune tolerance therapy, and needs of older adults with hemophilia and an inhibitor. For more information, visit https://www.hemophilia.org/Events-Educational-Programs/Inhibitor-Education/Inhibitor-Education-Summits The NHF’s Inhibitor Education Summits ...

  6. FLORESCIMENTO E FRUTIFICAÇÃO DE MANGUEIRA COM USO DE PACLOBUTRAZOL, ETHEPHON E NITRATO DE CÁLCIO FLOWERING AND FRUTIFICATION OF MANGO WITH USE OF PACLOBUTRAZOL, ETHEPHON AND CALCIUM NITRATE

    Directory of Open Access Journals (Sweden)

    VANDER MENDONÇA

    2001-08-01

    Full Text Available Este trabalho objetivou testar diferentes doses de Paclobutrazol (PBZ, ethephon e nitrato de cálcio na indução do florescimento e na produção da mangueira (Mangifera indica L. cv. Tommy Atkins, localizada no pomar didático da ESAM em Mossoró-RN, no ano de 1999/2000. O delineamento experimental utilizado foi em blocos casualizados, no esquema fatorial 2x2x3, assim distribuídos: T1 1000 mg.L-1 de PBZ+ 2% de nitrato de cálcio; T2 1000 mg.L-1 de PBZ + 2% de nitrato de cálcio + 1,0 mL.L-1 de ethephon; T3 1000 mg.L-1 de PBZ + 2% de nitrato de cálcio + 3,0 mL.L-1 de ethephon; T4 1000 mg. L-1 de PBZ + 3% de nitrato de cálcio; T5 1000 mg.L-1 de PBZ + 3% de nitrato de cálcio + 1,0 mL.L-1 de ethephon; T6 1000 mg.L-1 de PBZ + 3% de nitrato de cálcio + 3,0 mL.L-1 de ethephon ; T7 1500 mg.L-1 de PBZ + 2% de nitrato de cálcio; T8 1500 mg.L-1 de PBZ + 2% de nitrato de cálcio + 1,0 mL.L-1 de ethephon; T9 1500 mg.L-1 de PBZ + 2% de nitrato de cálcio + 3,0 mL.L-1 de ethephon; T10 1500 mg.L-1 de PBZ+ 3% de nitrato de cálcio; T11 1500 mg.L-1 de PBZ + 3% de nitrato de cálcio + 1,0 mL.L-1 de ethephon.L; T12 1500 mg.L-1 de PBZ + 3% de nitrato de cálcio + 3,0 mL.L-1 de ethephon, com 4 repetições. A mangueira teve um maior florescimento (81,75% com 2% de nitrato de cálcio e 1500 mg. L-1 de PBZ, o número de frutos por planta teve seu maior valor (86 frutos com 3% de nitrato de c��lcio e 1500 mg L-1 de PBZ e o peso do fruto foi maior (425,5g na dosagem de 3mL.L-1 de ethephon. Os produtos aplicados não diferenciaram entre si em relação à produção.This work had the objective of testing distinct concentrations of Paclobutrazol, ethephon and calcium nitrate to induce flowering in the production of the mango cv. Tommy Atkins, located in the didactic orchard of the Superior School of Agriculture of Mossoró. The experiment was developped in the year of 1999/2000. A randomized experimental block design, was used in the factorial scheme 2x2x3

  7. Infusum Daun Alpukat Sebagai Inhibitor Kristalisasi Kalsium Oksalat pada Ginjal (THE AVOCADO LEAVES INFUSUM AS INHIBITOR ON RENAL CALCIUM OXALATE CRYSTALIZATION

    Directory of Open Access Journals (Sweden)

    Rini Madyastuti

    2016-01-01

    Full Text Available Urine crystal is a crystal nucleus which tend to form urine stone. The case of urine stone seems to beincreased every year. Crystallization could induce acute tubular necrosis which impact on renal dysfunction.The signs of this condition are high level of urea, creatinine and decrease glomerulus filtration rate. Theobjective of this research was to evaluate the effects of infusum Persea americana Mill as an inhibitorcrystallization which induced by ethylene glycol on white male rats. 20 male rats were divided into 4groups; K1 as negative group received only distilled water ad libitum, K2 as positive group receiveddistilled water containing ethylene glycol, K3 (dose 5% and K4 (dose 10% as treatment groups receivedwater containing ethylene glycol and avocado leaves infusion. Phytochemsitry screening of infusion avocadoleaves consisted of flavonoid, saponin, tanine and quinone. Result of analysis showed that the level ofureum and creatinine on K2 was higher than K3 and K4 group. The increased level could be inhibited byinfusion avocado leaves. The measurement of glomerular filtration rate in treatment groups wassignificantly different (p<0.05. Descriptive histopathology observation showed that renal lesio in grouptreatment (K3 and K4 were declined. Large crystal calcium oxalate on K2 group was observed by usingpolarized microscope, whereas small crystal calcium oxalate were seen in the infusion of avocado leavesgroups. These result showed the ability of infusion of avocado leaves as an inhibitor on the growth ofcrystallization calcium oxalate

  8. Current concepts in combination therapy for the treatment of hypertension: combined calcium channel blockers and RAAS inhibitors

    Directory of Open Access Journals (Sweden)

    Alberto F Rubio-Guerra

    2009-11-01

    Full Text Available Alberto F Rubio-Guerra1, David Castro-Serna2, Cesar I Elizalde Barrera2, Luz M Ramos-Brizuela21Metabolic and Research Clinic, 2Internal Medicine Department, Hospital General de Ticomán SS DF, MéxicoAbstract: Recent guidelines for the management of hypertension recommend target blood pressures <140/90 mmHg in hypertensive patients, or <130/80 mmHg in subjects with diabetes, chronic kidney disease, or coronary artery disease. Despite the availability and efficacy of antihypertensive drugs, most hypertensive patients do not reach the recommended treatment targets with monotherapy, making combination therapy necessary to achieve the therapeutic goal. Combination therapy with 2 or more agents is the most effective method for achieving strict blood pressure goals. Fixed-dose combination simplifies treatment, reduces costs, and improves adherence. There are many drug choices for combination therapy, but few data are available about the efficacy and safety of some specific combinations. Combination therapy of calcium antagonists and inhibitors of the renin-angiotensin-aldosterone system (RAAS are efficacious and safe, and have been considered rational by both the JNC 7 and the 2007 European Society of Hypertension – European Society of Cardiology guidelines for the management of arterial hypertension. The aim of this review is to discuss some relevant issues about the use of combinations with calcium channel blockers and RAAS inhibitors in the treatment of hypertension.Keywords: hypertension, calcium channel blockers, renin-angiotensin-aldosterone system inhibitors, fixed-dose combination, adherence

  9. Optimization of an Imidazopyridazine Series of Inhibitors of Plasmodium falciparum Calcium-Dependent Protein Kinase 1 (PfCDPK1)

    OpenAIRE

    Chapman, Timothy M.; Osborne, Simon A.; Wallace, Claire; Birchall, Kristian; Bouloc, Nathalie; Jones, Hayley M.; Ansell, Keith H.; Taylor, Debra L.; Clough, Barbara; Green, Judith L.; Holder, Anthony A.

    2014-01-01

    A structure-guided design approach using a homology model of Plasmodium falciparum calcium-dependent protein kinase 1 (PfCDPK1) was used to improve the potency of a series of imidazopyridazine inhibitors as potential antimalarial agents. This resulted in high affinity compounds with PfCDPK1 enzyme IC50 values less than 10 nM and in vitro P. falciparum antiparasite EC50 values down to 12 nM, although these compounds did not have suitable ADME properties to show in vivo efficacy in a mouse mode...

  10. [Does the diuretic effect of calcium inhibitors play an important role in the hypertensive efficacy?].

    Science.gov (United States)

    Maldonado Martin, A; Gil Extremera, B; Rubio Luengo, M A

    1995-04-08

    Calcium ions play an important role in the pathophysiology of hypertension. Calcium antagonists, a group of first line drugs in the treatment of hypertension, reduce the intracellular content of calcium in vascular smooth muscle cells, and decrease the peripheral vascular resistance and blood pressure. These drugs differ from other vasodilators in that they also have natriuretic effects; thus they can affect the kidney on three levels: Renal haemodynamics are affected by increased renal blood flow, and increased glomerular filtration rate. Changes in the renin-angiotensin system can decrease aldosterone secretion. Finally, they affect sodium management by acting directly on the renal tubule, increasing sodium excretion and inhibiting tubular reabsorption of this ion. The natriuretic effect of calcium antagonists is independent of the subject's sodium balance. The vasodilating action of these drugs is therefore accompanied by a natriuretic effect that makes satisfactory control of hypertension possible without placing the patient on a low-salt or salt-free diet.

  11. Ilex paraguariensis extracts are potent inhibitors of nitrosative stress: a comparative study with green tea and wines using a protein nitration model and mammalian cell cytotoxicity.

    Science.gov (United States)

    Bixby, Mindy; Spieler, Lauren; Menini, Teresita; Gugliucci, Alejandro

    2005-06-03

    Due to the increasing importance of nitrosative stress in pathology and the efficacy displayed by flavonoids in cancelling the effects of peroxynitrite, we decided to conduct a comparative study of three commonly used beverages with the highest polyphenol contents and proven antioxidant properties: mate (Ilex paraguariensis); green tea (Camelia sinensis) extracts and white and red wines of the main varietals. We directly evaluated and compared the extracts and wines as protein nitration inhibitors using 3-nitrotyrosine as a biomarker, we studied the extracts as protectors from OONO-induced cytotoxicity in two mammalian cell lines. Both green tea and mate extracts have a high polyphenol content, in the case of Ip, its higher concentration and higher free radical quenching activity on the DPPH assay may be mainly due to the sui generis extraction procedure. When BSA was incubated in the presence of SIN-1, a time and dose dependent nitration of the protein is clearly shown. Co-incubation of BSA with Ip, green tea or red wines led to a dose dependent inhibition of the effect. Ip displayed the highest inhibitory activity, followed by red wines and the green tea. Dilutions as low as 1/1500 produced more than 80% inhibition of albumin nitration. When we studied peroxynitrite-induced cytotoxicity in murine RAW 264.7 macrophages and 31EG4 mammary cells., we found a potent, dose-dependent protective effect that was Ilex paraguariensis > red wines > green tea. Taken together, our results indicate that when the herbal preparations studied here are prepared the way they are usually drunk, Ip displays the highest inhibition of protein nitration, and the highest promotion of cell survival, whereas green tea or red wines display significant but lesser effects at the same concentrations. Further studies aiming at isolation of the active principles and assessment of their bioavailability are warranted.

  12. Effect of Angiotensin-Converting Enzyme Inhibitor/Calcium Antagonist Combination Therapy on Renal Function in Hypertensive Patients With Chronic Kidney Disease: Chikushi Anti-Hypertension Trial - Benidipine and Perindopril.

    Science.gov (United States)

    Okuda, Tetsu; Okamura, Keisuke; Shirai, Kazuyuki; Urata, Hidenori

    2018-02-01

    Appropriate blood pressure control suppresses progression of chronic kidney disease (CKD). If an angiotensin-converting enzyme (ACE) inhibitor is ineffective, adding a calcium antagonist is recommended. We compared the long-term effect of two ACE inhibitor/calcium antagonist combinations on renal function in hypertensive patients with CKD. Patients who failed to achieve the target blood pressure (systolic/diastolic: hypertensive patients with diabetic nephropathy, combined therapy with an ACE inhibitor and T/L type calcium antagonist may prevent deterioration of renal function more effectively than an ACE inhibitor/L type calcium antagonist combination.

  13. Application of poly(aspartic acid-citric acid copolymer compound inhibitor as an effective and environmental agent against calcium phosphate in cooling water systems

    Directory of Open Access Journals (Sweden)

    Yu-ling Zhang

    2016-12-01

    Full Text Available Poly(aspartic acid-citric acid copolymer (PAC is a new product of poly(carboxylic acid scale inhibitor. The study aims to develop a “green” water treatment agent for calcium phosphate scale. The article compares the efficiency of three polymeric antiscalants, poly(aspartic acid-citric acid copolymer (PAC, polymaleic acid (HPMA and a compound inhibitor (PAC-HPMA, for calcium phosphate scale prevention under varying experimental conditions. Inhibitor concentration, calcium concentration, system pH, temperature and experimental time were varied to determine their influences on inhibitor performance by the static scale inhibition method. The copolymer (PAC was characterized by FTIR, 1H NMR and 13C NMR. The compound inhibitor was applied in the actual circulating cooling water system. An atomic force microscope (AFM, X-ray powder diffraction (XRD and a scale formation process analysis were used to explore the scale inhibition mechanism. The results showed that scale inhibition rates of PAC, HPMA and PAC-HPMA against Ca3(PO42 were, respectively, about 23%, 41.5% and 63% when the dosage was 8 mg/L in the experiment. The compound inhibitor showed the better inhibition performance than the above two kinds of monomers. Under the actual working conditions, the inhibition rate of compound inhibitor was close to 100% and completely met the actual application requirements of scale inhibitor in circulating cooling water systems. The main inhibition mechanism was the decomposition-chelation dispersion effect. The compound inhibitor can be used as an efficient “green” scale inhibitor for calcium phosphate.

  14. A high-throughput assay for evaluating state dependence and subtype selectivity of Cav2 calcium channel inhibitors.

    Science.gov (United States)

    Dai, Ge; Haedo, Rodolfo J; Warren, Vivien A; Ratliff, Kevin S; Bugianesi, Randal M; Rush, Alison; Williams, Mark E; Herrington, James; Smith, McHardy M; McManus, Owen B; Swensen, Andrew M

    2008-04-01

    Cav2.2 channels play a critical role in pain signaling by controlling synaptic transmission between dorsal root ganglion neurons and dorsal horn neurons. The Cav2.2-selective peptide blocker ziconotide (Prialt, Elan Pharmaceuticals, Dublin, Ireland) has proven efficacious in pain relief, but has a poor therapeutic index and requires intrathecal administration. This has provided impetus for finding an orally active, state-dependent Cav2.2 inhibitor with an improved safety profile. Members of the Cav2 subfamily of calcium channels are the main contributors to central and peripheral synaptic transmission, but the pharmacological effects of blocking each subtype is not yet defined. Here we describe a high-throughput fluorescent assay using a fluorometric imaging plate reader (FLIPR [Molecular Devices, Sunnyvale, CA]) designed to quickly evaluate the state dependence and selectivity of inhibitors across the Cav2 subfamily. Stable cell lines expressing functional Cav2 channels (Ca(V)alpha, beta(3), and alpha(2)delta subunits) were co-transfected with an inward rectifier (Kir2.3) so that membrane potential, and therefore channel state, could be controlled by external potassium concentration. Following cell incubation in drug with varying concentrations of potassium, a high potassium trigger was added to elicit calcium influx through available, unblocked channels. State-dependent inhibitors that preferentially bind to channels in the open or inactivated state can be identified by their increased potency at higher potassium concentrations, where cells are depolarized and channels are biased towards these states. Although the Cav2 channel subtypes differ in their voltage dependence of inactivation, by adjusting pre-trigger potassium concentrations, the degree of steady-state inactivation can be more closely matched across Cav2 subtypes to assess molecular selectivity.

  15. Combination effect of sponge iron and calcium nitrate on severely eutrophic urban landscape water: an integrated study from laboratory to fields.

    Science.gov (United States)

    Wang, Guan-Bai; Wang, Yi; Zhang, Ying

    2018-01-06

    In this study, the in situ restoration of urban landscape water through the combined application of sponge iron (SI) and calcium nitrate (CN) was conducted in the Xi'an Moat of China. The combination effect of SI and CN on the phosphorus (P) control was explored through laboratory and field experiments. Results showed that the optimum mass ratio of SI and CN was 4:1, and the optimum dosage of combined SI and CN was 1.4 g/L for controlling eutrophication in the water body at Xi'an Moat. The field experiment demonstrated that SI and CN efficiently controlled P concentration in overlying and interstitial water and obtained a maximum efficiency of 88.6 and 65.2% in soluble reactive P locking, respectively. The total P, organic P, and Ca-bound P contents in sediment simultaneously increased by 7.7, 15.2, and 2.4%, respectively, after 56 days. Therefore, the combined application of SI and CN achieved the goal of transferring the P from overlying and interstitial water to the sediment. Considering the environmental effect and economic investment, the combined application of SI and CN at a mass ratio of 4:1 and dosage of 1.4 g/L is an excellent choice for the in situ rehabilitation of eutrophic water with a high internal P load.

  16. Content of zinc, iron, calcium and their absorption inhibitors in foods commonly consumed in Ethiopia

    NARCIS (Netherlands)

    Umeta, M.; West, C.E.; Fufa, H.

    2005-01-01

    The zinc, iron, calcium, phosphorus, phytate, tannin and moisture content of 36 foods consumed in rural Ethiopia were analysed. The foods analysed included those based on cereals, starchy tubers and roots, and legumes and vegetables as well as some fruits. Although many foods were relatively rich in

  17. Calcium ionophore (A-23187 induced peritoneal eicosanoid biosynthesis: a rapid method to evaluate inhibitors of arachidonic acid metabolism in vivo

    Directory of Open Access Journals (Sweden)

    T. S. Rao

    1993-01-01

    Full Text Available The present investigation characterizes calcium ionophore (A-23187 induced peritoneal eicosanoid biosynthesis in the rat. Intraperitoneal injection of A-23187 (20 μg/rat stimulated marked biosynthesis of 6-keto-PGF1α (6-KPA, TxB2, LTC4 and LTB4, with no detectable changes on levels of PGE2. Levels of all eicosanoids decreased rapidly after a peak which was seen as early as 5 min. Enzyme markers of cellular contents of neutrophils and mononuclear cells, MPO and NAG respectively, decreased rapidly after ionophore injection; this was followed by increases after 60 min. Indomethacin, a selective cyclooxygenase inhibitor, and zileuton and ICI D-2138, two selective 5-lipoxygenase inhibitors attenuated prostaglandin and leukotriene pathways respectively. Oral administration of zileuton (20 mg/kg, p.o. inhibited LTB4 biosynthesis for up to 6 h suggesting a long duration of pharmacological activity in the rats consistent with its longer half-life. The rapid onset and the magnitude of increases in levels of eicosanoids render the ionophore induced peritoneal eicosanoid biosynthesis a useful model to evaluate pharmacological profiles of inhibitors of eicosanoid pathways in vivo.

  18. ACE inhibitors and calcium antagonists in the treatment of congestive heart failure

    DEFF Research Database (Denmark)

    Hansen, J F

    1995-01-01

    The increased mortality after myocardial infarction is related to the risk of reinfarction, sudden death, and the development and progression of heart failure; in congestive heart failure it is due to the progression of heart failure and sudden death. ACE inhibitors have been proven to prevent...... cardiovascular events, especially the progression of heart failure, in postinfarct patients with reduced ejection fraction and heart failure in the SAVE and AIRE trials. In patients with congestive heart failure, ACE inhibitor treatment has prevented cardiovascular death and reduced morbidity due to progressive...... by prevention of reinfarction and sudden death. Combination treatment with both verapamil, which has pronounced antiischemic properties and prevents sudden death and reinfarction, and an ACE inhibitor, which prevents the progression of heart failure, is a possibility for future cardiovascular therapy...

  19. Low-dose combination therapy: the rationalization for an ACE inhibitor and a calcium channel blocker in higher risk patients.

    Science.gov (United States)

    Kaplan, N M

    2001-05-01

    As more high-risk hypertensives are treated and the need for more intensive antihypertensive therapy is recognized, combination therapies are increasingly used. For initial therapy, particularly for relatively low-risk patients, low-dose combinations are often appropriate. For those who require additional therapy, higher doses of combinations may provide further efficacy while minimizing dose-dependent side effects of monotherapy, thereby improving adherence to therapy. Those combination agents should provide 24-h control with one daily dose, thereby ensuring protection in the early morning hours. Combining an angiotensin converting enzyme inhibitor and a calcium channel blocker is a rational approach to treating hypertension. Not only does it provide significantly better blood pressure control than individual components used as monotherapy, it also minimizes dose-dependent side effects. Also, combining agents from different classes results in complementary mechanisms of action that provide other cardiovascular protective benefits.

  20. Ion and inhibitor binding of the double-ring ion selectivity filter of the mitochondrial calcium uniporter.

    Science.gov (United States)

    Cao, Chan; Wang, Shuqing; Cui, Tanxing; Su, Xun-Cheng; Chou, James J

    2017-04-04

    The calcium (Ca2+) uniporter of mitochondria is a holocomplex consisting of the Ca2+-conducting channel, known as mitochondrial calcium uniporter (MCU), and several accessory and regulatory components. A previous electrophysiology study found that the uniporter has high Ca2+ selectivity and conductance and this depends critically on the conserved amino acid sequence motif, DXXE (Asp-X-X-Glu) of MCU. A recent NMR structure of the MCU channel from Caenorhabditis elegans revealed that the DXXE forms two parallel carboxylate rings at the channel entrance that seem to serve as the ion selectivity filter, although direct ion interaction of this structural motif has not been addressed. Here, we use a paramagnetic probe, manganese (Mn2+), to investigate ion and inhibitor binding of this putative selectivity filter. Our paramagnetic NMR data show that mutants with a single carboxylate ring, NXXE (Asn-X-X-Glu) and DXXQ (Asp-X-X-Gln), each can bind Mn2+ specifically, whereas in the WT the two rings bind Mn2+ cooperatively, resulting in ∼1,000-fold higher apparent affinity. Ca2+ can specifically displace the bound Mn2+ at the DXXE site in the channel. Furthermore, titrating the sample with the known channel inhibitor ruthenium 360 (Ru360) can displace Mn2+ binding from the solvent-accessible Asp site but not the inner Glu site. The NMR titration data, together with structural analysis of the DXXE motif and molecular dynamics simulation, indicate that the double carboxylate rings at the apex of the MCU pore constitute the ion selectivity filter and that Ru360 directly blocks ion entry into the filter by binding to the outer carboxylate ring.

  1. The effect of calcium channel blockers and calmodulin inhibitors on the macrophage factor-stimulated synthesis of collagenase by rabbit chondrocytes.

    Science.gov (United States)

    Nolan, J C; Gathright, C E; Wagner, L E

    1988-08-01

    Macrophages and monocytes secrete a factor(s) which can stimulate the synthesis of collagenase in synovial cells and in chondrocytes. Incubation of rabbit chondrocytes with macrophage conditioned medium (MCM) and with the calcium channel blockers, nifedipine, verapamil or diltiazem (up to 200 microM) had no effect on collagenase synthesis. However, TMB-8 (8-[N,N-diethylamino]-octyl 3,4,5-trimethoxybenzoate hydrochloride), an inhibitor of internal calcium movement, did inhibit the process with an IC50 of approximately 130 microM. The calmodulin antagonists, trifluoperazine, chlorpromazine and calmidazolium (R-24571) were effective inhibitors of the process with IC50's of 40 microM, 18 microM and 3.5 microM, respectively. Collagenase activity itself was not affected by these agents. The data suggests that calmodulin and/or internal calcium movement may play a role in the macrophage factor-stimulated synthesis of collagenase in rabbit chondrocytes.

  2. Process for preparing concentrated byproduct nitrate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Rado, T.A.

    1988-07-12

    This patent describes a process for preparing a concentrated aqueous solution of ammonium nitrate, further containing sulfate ions and a substantially reduced portion of calcium ions from a dilute aqueous waste stream. The stream is characterized by having a neutral pH and containing ammonium nitrate and sulfate ions and calcium ions.

  3. Differential nitrate accumulation, nitrate reduction, nitrate reductase ...

    African Journals Online (AJOL)

    Differential nitrate accumulation, nitrate reduction, nitrate reductase activity, protein production and carbohydrate biosynthesis in response to potassium and sodium ... due to the positive effects of potassium on the enzyme activity, sugars transport, water and nutrient transport, protein synthesis and carbohydrate metabolism.

  4. [Effect of calcium-independent phospholipase A(2) inhibitor in reducing hepatocyte lipoapoptosis and improving insulin resistance].

    Science.gov (United States)

    Shi, H B; Fu, J F; Huang, Y; Liu, L R

    2017-01-20

    Objective: To investigate the effect of calcium-independent phospholipase A(2) (iPLA(2)) inhibitor in reducing hepatocyte lipoapoptosis and improving insulin resistance. Methods: A total of 28 male Sprague-Dawley rats were randomly divided into the following three groups: 12 rats in group I (normal control group) were given normal diet for 18 weeks; 8 rats in group II (non-alcoholic fatty liver disease model group) were given high-fat diet for 18 weeks; 8 rats in group III (iPLA(2) inhibitor group) were given high-fat diet for 18 weeks and intraperitoneal injection of the iPLA(2) inhibitor bromoenol lactone 150 μg/kg once every other day since week 15 (14 times of injection in total). All the rats were sacrificed at the same time, and body weight and liver weight were measured. Blood lipids, serum enzymes, fasting blood glucose, fasting insulin, free fatty acid, and serum iPLA(2) concentration were measured in each group, and liver pathological changes were evaluated. The terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling was used to measure the level of hepatocyte apoptosis and the apoptotic index was calculated. Quantitative PCR was used to measure the mRNA expression of iPLA(2). The Student-Newman-Keuls test and the chi-square test were used for comparison of parameters between groups I, II, and III. P increases in triglyceride (0.75±0.05 mmol/L vs 1.20±0.13 mmol/L, P insulin (0.89±0.52 mmol/L vs 1.29±0.52 mmol/L, P insulin sensitivity index (0.52±0.21 vs 0.27±0.11, P increases in apoptotic cells and apoptotic index (0.58%±0.17% vs 39.69%±4.96%, P increases in serum iPLA(2) concentration (2.92±0.08 ng/ml vs 3.28±0.14 ng/ml, P insulin (1.29±0.52 mmol/L vs 0.80±0.09 mmol/L, P increase in insulin sensitivity index (0.27±0.11 vs 0.45±0.09, P increase in the expression of iPLA(2) in rats with non-alcoholic fatty liver disease, and iPLA2 inhibitor can reduce hepatocyte lipoapoptosis and improve insulin resistance.

  5. Use of digoxin, diuretics, beta blockers, angiotensin-converting enzyme inhibitors, and calcium channel blockers in older patients in an academic hospital-based geriatrics practice.

    Science.gov (United States)

    Fishkind, D; Paris, B E; Aronow, W S

    1997-07-01

    To investigate the prevalence of and indications for digoxin use and the prevalence of beta blocker and calcium channel blocker use in older patients with previous myocardial infarction or coronary artery disease (CAD), and the prevalence of use of diuretics, beta blockers, angiotensin-converting enzyme (ACE) inhibitors, and calcium channel blockers in older patients with hypertension in an academic hospital-based geriatrics practice. A retrospective analysis of charts from 528 unselected older patients, seen from June 1995 through July 1996 at an academic hospital-based geriatrics practice, was performed to investigate the prevalence of digoxin use and indications for digoxin use, the prevalence of beta blocker and calcium channel blocker use in older patients with previous myocardial infarction or coronary artery disease (CAD), and the prevalence of use of diuretics, beta blockers, angiotensin-converting enzyme (ACE) inhibitors, and calcium channel blockers in older patients with hypertension. An academic hospital-based, primary care geriatrics practice staffed by fellows in a geriatrics training program and full-time faculty geriatricians. A total of 416 women and 112 men, mean age 81 +/- 8 years (range 58 to 101), were included in the study. Ninety-two of the 528 patients (17%) were taking digoxin. Recorded indications for digoxin were atrial fibrillation with or without congestive heart failure (CHF) in 39% of patients, CHF with sinus rhythm and abnormal left ventricular ejection fraction (LVEF) in 18% of patients, a clinical assessment of CHF with sinus rhythm and no recorded measurement of LVEF in 20% of patients, paroxysmal atrial fibrillation in 14% of patients, and coronary artery disease (CAD) in 9% of patients. Of 121 patients with previous myocardial infarction, 23 (19%) were prescribed beta blockers, and 54 (45%) were taking calcium channel blockers. Of 173 patients with CAD, 41 (24%) were treated with beta blockers, and 79 (46%) were taking calcium

  6. Intercomparison 9610, pH, conductivity, alkalinity, nitrate + nitrite, chloride, sulfate, calcium, magnesium, sodium, potassium, total aluminium, reactive and non-labile aluminium, dissolved organic carbon, and chemical oxygen demand (ICP Waters report)

    OpenAIRE

    Hovind, H.

    1996-01-01

    36 laboratories in 21 countries participated in intercomparison 9610. Two sample sets, one for the major ions and one for organic matter and aluminium fractions, were used. Based on the general target accuracy of + 20%, 70% of the results were acceptable. More than 80% of the result pairs were acceptable for conductivity, nitrate+nitrite, calcium, sodium and dissolved organic carbon. For pH only 55% of the result pairs were acceptable in relation to the extended target accuracy of + 0.2 units...

  7. ω-Tbo-IT1-New Inhibitor of Insect Calcium Channels Isolated from Spider Venom.

    Science.gov (United States)

    Mikov, Alexander N; Fedorova, Irina M; Potapieva, Natalia N; Maleeva, Ekaterina E; Andreev, Yaroslav A; Zaitsev, Alexey V; Kim, Kira K; Bocharov, Eduard V; Bozin, Timur N; Altukhov, Dmitry A; Lipkin, Alexey V; Kozlov, Sergey A; Tikhonov, Denis B; Grishin, Eugene V

    2015-11-27

    Novel disulfide-containing polypeptide toxin was discovered in the venom of the Tibellus oblongus spider. We report on isolation, spatial structure determination and electrophysiological characterization of this 41-residue toxin, called ω-Tbo-IT1. It has an insect-toxic effect with LD50 19 μg/g in experiments on house fly Musca domestica larvae and with LD50 20 μg/g on juvenile Gromphadorhina portentosa cockroaches. Electrophysiological experiments revealed a reversible inhibition of evoked excitatory postsynaptic currents in blow fly Calliphora vicina neuromuscular junctions, while parameters of spontaneous ones were not affected. The inhibition was concentration dependent, with IC50 value 40 ± 10 nM and Hill coefficient 3.4 ± 0.3. The toxin did not affect frog neuromuscular junctions or glutamatergic and GABAergic transmission in rat brains. Ca(2+) currents in Calliphora vicina muscle were not inhibited, whereas in Periplaneta americana cockroach neurons at least one type of voltage gated Ca(2+) current was inhibited by ω-Tbo-IT1. Thus, the toxin apparently acts as an inhibitor of presynaptic insect Ca(2+) channels. Spatial structure analysis of the recombinant ω-Tbo-IT1 by NMR spectroscopy in aqueous solution revealed that the toxin comprises the conventional ICK fold containing an extended β-hairpin loop and short β-hairpin loop which are capable of making "scissors-like mutual motions".

  8. Long-term mTOR inhibitors administration evokes altered calcium homeostasis and platelet dysfunction in kidney transplant patients

    Science.gov (United States)

    López, Esther; Berna-Erro, Alejandro; Bermejo, Nuria; Brull, José María; Martinez, Rocío; Garcia Pino, Guadalupe; Alvarado, Raul; Salido, Ginés María; Rosado, Juan Antonio; Cubero, Juan José; Redondo, Pedro Cosme

    2013-01-01

    The use of the mammal target of rapamycin (mTOR) inhibitors has been consolidated as the therapy of election for preventing graft rejection in kidney transplant patients, despite their immunosuppressive activity is less strong than anti-calcineurin agents like tacrolimus and cyclosporine A. Furthermore, as mTOR is widely expressed, rapamycin (a macrolide antibiotic produced by Streptomyces hygroscopicus) is recommended in patients presenting neoplasia due to its antiproliferative actions. Hence, we have investigated whether rapamycin presents side effects in the physiology of other cell types different from leucocytes, such as platelets. Blood samples were drawn from healthy volunteers and kidney transplant patients long-term medicated with rapamycin: sirolimus and everolimus. Platelets were either loaded with fura-2 or directly stimulated, and immunoassayed or fixed with Laemmli's buffer to perform the subsequent analysis of platelet physiology. Our results indicate that rapamycin evokes a biphasic time-dependent alteration in calcium homeostasis and function in platelets from kidney transplant patients under rapamycin regime, as demonstrated by the reduction in granule secretion observed and subsequent impairment of platelet aggregation in these patients compared with healthy volunteers. Platelet count was also reduced in these patients, thus 41% of patients presented thrombocytopenia. All together our results show that long-term administration of rapamycin to kidney transplant patients evokes alteration in platelet function. PMID:23577651

  9. Targeting voltage-gated calcium channels: developments in peptide and small-molecule inhibitors for the treatment of neuropathic pain

    Science.gov (United States)

    Vink, S; Alewood, PF

    2012-01-01

    Chronic pain affects approximately 20% of people worldwide and places a large economic and social burden on society. Despite the availability of a range of analgesics, this condition is inadequately treated, with complete alleviation of symptoms rarely occurring. In the past 30 years, the voltage-gated calcium channels (VGCCs) have been recognized as potential targets for analgesic development. Although the majority of the research has been focused on Cav2.2 in particular, other VGCC subtypes such as Cav3.2 have recently come to the forefront of analgesic research. Venom peptides from marine cone snails have been proven to be a valuable tool in neuroscience, playing a major role in the identification and characterization of VGCC subtypes and producing the first conotoxin-based drug on the market, the ω-conotoxin, ziconotide. This peptide potently and selectively inhibits Cav2.2, resulting in analgesia in chronic pain states. However, this drug is only available via intrathecal administration, and adverse effects and a narrow therapeutic window have limited its use in the clinic. Other Cav2.2 inhibitors are currently in development and offer the promise of an improved route of administration and safety profile. This review assesses the potential of targeting VGCCs for analgesic development, with a main focus on conotoxins that block Cav2.2 and the developments made to transform them into therapeutics. PMID:22725651

  10. Nitrate reduction

    Science.gov (United States)

    Dziewinski, Jacek J.; Marczak, Stanislaw

    2000-01-01

    Nitrates are reduced to nitrogen gas by contacting the nitrates with a metal to reduce the nitrates to nitrites which are then contacted with an amide to produce nitrogen and carbon dioxide or acid anions which can be released to the atmosphere. Minor amounts of metal catalysts can be useful in the reduction of the nitrates to nitrites. Metal salts which are formed can be treated electrochemically to recover the metals.

  11. Differential nitrate accumulation, nitrate reduction, nitrate reductase ...

    African Journals Online (AJOL)

    use

    2011-12-07

    Dec 7, 2011 ... biosynthesis. Carbohydrate metabolism produces both the carbon skeletons and ferredoxin for nitrate assimilation. Inhibition of photosynthesis prevents the production of the reduced ferredoxin required for nitrite reduction in chloroplasts, which leads to nitrate and nitrite accumulation (Commichau et al., ...

  12. Role of prefrontal cortical calcium-independent phospholipase A2 in antinociceptive effect of the norepinephrine reuptake inhibitor antidepresssant maprotiline.

    Science.gov (United States)

    Chew, Wee-Siong; Shalini, Suku-Maran; Torta, Federico; Wenk, Markus R; Stohler, Christian; Yeo, Jin-Fei; Herr, Deron R; Ong, Wei-Yi

    2017-01-06

    The prefrontal cortex is essential for executive functions such as decision-making and planning. There is also accumulating evidence that it is important for the modulation of pain. In this study, we investigated a possible role of prefrontal cortical calcium-independent phospholipase A2 (iPLA2) in antinociception induced by the norepinephrine reuptake inhibitor (NRI) and tetracyclic (tricyclic) antidepressant, maprotiline. Intraperitoneal injections of maprotiline increased iPLA2 mRNA and protein expression in the prefrontal cortex. This treatment also reduced grooming responses to von-Frey hair stimulation of the face after facial carrageenan injection, indicating decreased sensitivity to pain. The antinociceptive effect of maprotiline was abrogated by iPLA2 antisense oligonucleotide injection to the prefrontal cortex, indicating a role of this enzyme in antinociception. In contrast, injection of iPLA2 antisense oligonucleotide to the somatosensory cortex did not reduce the antinociceptive effect of maprotiline. Lipidomic analysis of the prefrontal cortex showed decrease in phosphatidylcholine species, but increase in lysophosphatidylcholine species, indicating increased PLA2 activity, and release of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) after maprotiline treatment. Differences in sphingomyelin/ceramide were also detected. These changes were not observed in maprotiline-treated mice that received iPLA2 antisense oligonucleotide to the prefrontal cortex. Metabolites of DHA and EPA may help to strengthen a known supraspinal antinociceptive pathway from the prefrontal cortex to the periaqueductal gray. Together, results indicate a role of prefrontal cortical iPLA2 and its enzymatic products in the antinociceptive effect of maprotiline. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. Imidazopyridazines as potent inhibitors of Plasmodium falciparum calcium-dependent protein kinase 1 (PfCDPK1): Preparation and evaluation of pyrazole linked analogues

    OpenAIRE

    Large, Jonathan M.; Osborne, Simon A.; Smiljanic-Hurley, Ela; Ansell, Keith H.; Jones, Hayley M.; Taylor, Debra L.; Clough, Barbara; Green, Judith L.; Holder, Anthony A.

    2013-01-01

    The structural diversity and SAR in a series of imidazopyridazine inhibitors of Plasmodium falciparum calcium dependent protein kinase 1 (PfCDPK1) has been explored and extended. The opportunity to further improve key ADME parameters by means of lowering log?D was identified, and this was achieved by replacement of a six-membered (hetero)aromatic linker with a pyrazole. A short SAR study has delivered key examples with useful in vitro activity and ADME profiles, good selectivity against a hum...

  14. Inhibitors of ORAI1 Prevent Cytosolic Calcium-Associated Injury of Human Pancreatic Acinar Cells and Acute Pancreatitis in 3 Mouse Models.

    Science.gov (United States)

    Wen, Li; Voronina, Svetlana; Javed, Muhammad A; Awais, Muhammad; Szatmary, Peter; Latawiec, Diane; Chvanov, Michael; Collier, David; Huang, Wei; Barrett, John; Begg, Malcolm; Stauderman, Ken; Roos, Jack; Grigoryev, Sergey; Ramos, Stephanie; Rogers, Evan; Whitten, Jeff; Velicelebi, Gonul; Dunn, Michael; Tepikin, Alexei V; Criddle, David N; Sutton, Robert

    2015-08-01

    Sustained activation of the cytosolic calcium concentration induces injury to pancreatic acinar cells and necrosis. The calcium release-activated calcium modulator ORAI1 is the most abundant Ca(2+) entry channel in pancreatic acinar cells; it sustains calcium overload in mice exposed to toxins that induce pancreatitis. We investigated the roles of ORAI1 in pancreatic acinar cell injury and the development of acute pancreatitis in mice. Mouse and human acinar cells, as well as HEK 293 cells transfected to express human ORAI1 with human stromal interaction molecule 1, were hyperstimulated or incubated with human bile acid, thapsigargin, or cyclopiazonic acid to induce calcium entry. GSK-7975A or CM_128 were added to some cells, which were analyzed by confocal and video microscopy and patch clamp recordings. Acute pancreatitis was induced in C57BL/6J mice by ductal injection of taurolithocholic acid 3-sulfate or intravenous' administration of cerulein or ethanol and palmitoleic acid. Some mice then were given GSK-7975A or CM_128, which inhibit ORAI1, at different time points to assess local and systemic effects. GSK-7975A and CM_128 each separately inhibited toxin-induced activation of ORAI1 and/or activation of Ca(2+) currents after Ca(2+) release, in a concentration-dependent manner, in mouse and human pancreatic acinar cells (inhibition >90% of the levels observed in control cells). The ORAI1 inhibitors also prevented activation of the necrotic cell death pathway in mouse and human pancreatic acinar cells. GSK-7975A and CM_128 each inhibited all local and systemic features of acute pancreatitis in all 3 models, in dose- and time-dependent manners. The agents were significantly more effective, in a range of parameters, when given at 1 vs 6 hours after induction of pancreatitis. Cytosolic calcium overload, mediated via ORAI1, contributes to the pathogenesis of acute pancreatitis. ORAI1 inhibitors might be developed for the treatment of patients with pancreatitis

  15. Bone health and adherence to vitamin D and calcium therapy in early breast cancer patients on endocrine therapy with aromatase inhibitors.

    Science.gov (United States)

    Bošković, Lidija; Gašparić, Maja; Petković, Marija; Gugić, Damir; Lovasić, Ingrid Belac; Soldić, Željko; Miše, Branka Petrić; Dabelić, Nina; Vazdar, Ljubica; Vrdoljak, Eduard

    2017-02-01

    Randomized trials involving aromatase inhibitors (AIs) in the adjuvant treatment of breast cancer patients have reported increased osteoporosis risk. Bone loss can be reduced with appropriate life style, vitamin D and calcium supplements, and with bisphosphonate therapy. The aim of this analysis was to investigate adherence to vitamin D and calcium in postmenopausal breast cancer patients receiving adjuvant non-steroidal AIs, and oncologists' adherence to the bone health guidelines. This prospective study included 438 newly diagnosed patients and those who have already been receiving non-steroidal AIs for up to 3.5 years. Median endocrine therapy duration before recruitment in the study was 10.5 months (interquartile 4.8-26.6). Densitometry was performed on 142 patients (32.4%) before initiation of endocrine therapy, and on additional 38 (8.6%) patients at second study visit. Densitometry was not performed on 258 (59%) patients. Vitamin D and calcium were prescribed to 329/438 (75.1%) patients at some point during the study. Patients who took more than 80% of the prescribed dose were considered adherent. Self-reported adherence was 88.4%. Osteoporosis was diagnosed in 24 patients (5.5%) of the total study population, bearing in mind that 258/438 (59%) patients did not have densitometry. Bisphosphonates were prescribed to 54/438 (12.3%) patients, whilst only 19 (35.2%) of those had osteoporosis. In this analysis, lack of oncologists' adherence to the bone health guidelines was observed. In addition, a significant proportion of the patients did not adhere to the vitamin D and calcium. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Calcium channel blockers, angiotensin receptor blockers, and angiotensin-converting enzyme inhibitors: Effectiveness in combination with diuretics or β-blockers for treating hypertension

    Directory of Open Access Journals (Sweden)

    John D Bisognano

    2007-11-01

    Full Text Available John D Bisognano1, Trent McLaughlin2, Craig S Roberts3, Simon SK Tang31Internal Medicine Department, Cardiology Division, the University of Rochester Medical Center, Rochester, NY, USA; 2NDC Health, Phoenix, Arizona, USA; 3Pfizer Inc, New York, NY, USAAbstract: This retrospective database analysis compared the effectiveness of dihydropyridine calcium channel blockers (DHPs, angiotensin-converting enzyme (ACE inhibitors, and angiotensin receptor blockers (ARBs added to diuretics or β-blockers. Adults with hypertension treated with diuretic or β-blocker monotherapy between 1998 and 2001 were identified from a large US electronic medical records database of primary care practices. Patients were required to have a baseline blood pressure (BP ≥140/90 mmHg (≥130/80 mmHg for diabetes mellitus and recorded BP measurements within 6 months before and 1–12 months following index date. Patients were matched 1:1:1 by propensity score to correct for differences in baseline characteristics. 1875 patients met study criteria and 660 (220 in each cohort were matched based on propensity scores. Matched cohorts had no significant differences in baseline characteristics. Mean changes in systolic/diastolic BP were –17.5/–8.8, –15.7/–6.3, and –13.0/–8.0 mmHg with DHPs, ACE inhibitors, and ARBs, respectively. Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High BP 6/7 goal attainment for each regimen was 47.3%, 40.0%, and 32.2%, respectively. DHPs, ACE inhibitors, and ARBs improved BP when added to patients’ β-blocker or diuretic therapy. The greatest benefits were observed with DHPs, followed by ACE inhibitors, then ARBs.Keywords: hypertension, amlodipine besylate, lisinopril, valsartan, Joint National Committee (JNC 6 and 7

  17. Influence of beet sugar, calcium lactate, and Staphylococcus xylosus (with nitrate reductase activity) on the chemical, microbiological, and sensorial properties of Persian uncured frankfurters.

    Science.gov (United States)

    Tahmouzi, Saeed; Razavi, Seyed Hadi; Safari, Mohammad; Emam-Djomeh, Zahra

    2012-10-01

    This study investigated the effects of beet sugar (BS), calcium lactate (CL), and Staphylococcus xylosus (SX) on the general characteristics of uncured frankfurters. Minimum residual nitrite was observed in samples with a high level of BS and S. xylosus (8log(10) l0 viable cfu/g) after 2 mo. There was an increase in total aerobic counts in frankfurters after 4 wk. Samples containing higher BS and CL had no Clostridium perfringens at storage time. Histamine content was similar for all treatments except SX. No differences were observed in textural properties among the treatments. Water activity was decreased significantly in treatment CL1+BS2. The results indicated that samples treated with BS or CL had (P marketing these products. © 2012 Institute of Food Technologists®

  18. Pilot study to evaluate a water displacement technique to compare effects of diuretics and ACE inhibitors to alleviate lower extremity edema due to dihydropyridine calcium antagonists.

    Science.gov (United States)

    Weir, M R; Rosenberger, C; Fink, J C

    2001-09-01

    Combination therapy is required in many patients to achieve goal blood pressure (BP). Calcium antagonists are highly effective antihypertensive drugs in a broad range of demographic groups. Yet, higher doses are associated with an increased frequency of lower extremity edema. The purpose of our open label, single-center clinical trial was to evaluate the use of concomitant pharmacologic therapies to attenuate the lower extremity edema associated with dihydropyridine calcium antagonists therapy using a water displacement technique. Forty-seven patients received 5 mg/day of oral amlodipine for a period of 6 weeks after a 4-week wash-out off of all antihypertensive medications to establish baseline BP. They were then randomized to receive either an additional 5 mg of amlodipine, 25 mg of hydrochlorothiazide (HCTZ), or 20 mg of benazepril for an additional 6 weeks. Blood pressure determinations and water displacement measurements were obtained at the end of the 4-week placebo wash-out period, after 6 weeks of 5 mg/day of oral amlodipine therapy, and after an additional 6 weeks of 5 mg of amlodipine and randomized drug therapy. Adjusted BP reductions (based on pretreatment BP) were -6.8/-3.8 mm Hg for the 10-mg amlodipine group, -9.9/-8.2 mm Hg for the amlodipine (5 mg)/HCTZ (25 mg) group, and -26.2/-16.4 mm Hg for the amlodipine (5 mg)/benazepril (20 mg) group (P increase in lower extremity edema water displacement in response to 5 mg/day of oral amlodipine therapy (36.2%). Adding 5 mg of amlodipine to a baseline of 5 mg of amlodipine resulted in no net change in lower extremity edema (+58.0 mL,+ 0.6% change, n=5). Adding 25 mg of HCTZ reduced lower extremity edema by a mean of 136.3 mL (-11.1% change, n=4). Benazepril reduced water displacement by 204.4 mL (-14.3% change, n=8). Our pilot study indicates that adding an angiotensin converting enzyme inhibitor to a dihydropyridine calcium channel blocker is the most effective way to not only reduce systolic and diastolic

  19. Stapled Voltage-Gated Calcium Channel (CaV) α-Interaction Domain (AID) Peptides Act As Selective Protein-Protein Interaction Inhibitors of CaV Function.

    Science.gov (United States)

    Findeisen, Felix; Campiglio, Marta; Jo, Hyunil; Abderemane-Ali, Fayal; Rumpf, Christine H; Pope, Lianne; Rossen, Nathan D; Flucher, Bernhard E; DeGrado, William F; Minor, Daniel L

    2017-06-21

    For many voltage-gated ion channels (VGICs), creation of a properly functioning ion channel requires the formation of specific protein-protein interactions between the transmembrane pore-forming subunits and cystoplasmic accessory subunits. Despite the importance of such protein-protein interactions in VGIC function and assembly, their potential as sites for VGIC modulator development has been largely overlooked. Here, we develop meta-xylyl (m-xylyl) stapled peptides that target a prototypic VGIC high affinity protein-protein interaction, the interaction between the voltage-gated calcium channel (CaV) pore-forming subunit α-interaction domain (AID) and cytoplasmic β-subunit (CaVβ). We show using circular dichroism spectroscopy, X-ray crystallography, and isothermal titration calorimetry that the m-xylyl staples enhance AID helix formation are structurally compatible with native-like AID:CaVβ interactions and reduce the entropic penalty associated with AID binding to CaVβ. Importantly, electrophysiological studies reveal that stapled AID peptides act as effective inhibitors of the CaVα1:CaVβ interaction that modulate CaV function in an CaVβ isoform-selective manner. Together, our studies provide a proof-of-concept demonstration of the use of protein-protein interaction inhibitors to control VGIC function and point to strategies for improved AID-based CaV modulator design.

  20. Long-term mTOR inhibitors administration evokes altered calcium homeostasis and platelet dysfunction in kidney transplant patients

    OpenAIRE

    López, Esther; Berna-Erro, Alejandro; Bermejo, Nuria; Brull, José María; Martinez, Rocío; Garcia Pino, Guadalupe; Alvarado, Raul; Salido, Ginés María; Rosado, Juan Antonio; Cubero, Juan José; Redondo, Pedro Cosme

    2013-01-01

    The use of the mammal target of rapamycin (mTOR) inhibitors has been consolidated as the therapy of election for preventing graft rejection in kidney transplant patients, despite their immunosuppressive activity is less strong than anti-calcineurin agents like tacrolimus and cyclosporine A. Furthermore, as mTOR is widely expressed, rapamycin (a macrolide antibiotic produced by Streptomyces hygroscopicus) is recommended in patients presenting neoplasia due to its antiproliferative actions. Hen...

  1. Insights on alterations to the rumen ecosystem by nitrate and nitrocompounds

    Directory of Open Access Journals (Sweden)

    Elizabeth eLatham

    2016-03-01

    Full Text Available Nitrate and certain short chain nitrocompounds and nitro-oxy compounds are being investigated as dietary supplements to reduce economic and environmental costs associated with ruminal methane emissions. Thermodynamically, nitrate is a preferred electron acceptor in the rumen that consumes electrons at the expense of methanogenesis during dissimilatory reduction to an intermediate, nitrite, which is primarily reduced to ammonia although small quantities of nitrous oxide may also be produced. Short chain nitrocompounds act as direct inhibitors of methanogenic bacteria although certain of these compounds may also consume electrons at the expense of methanogenesis and are effective inhibitors of important foodborne pathogens. Microbial and nutritional consequences of incorporating nitrate into ruminant diets typically results in increased acetate production. Unlike most other methane-inhibiting supplements, nitrate decreases or has no effect on propionate production. The type of nitrate salt added influences rates of nitrate reduction, rates of nitrite accumulation and efficacy of methane reduction, with sodium and potassium salts being more potent than calcium nitrate salts. Digestive consequences of adding nitrocompounds to ruminant diets are more variable and may in some cases increase propionate production. Concerns about the toxicity of nitrate’s intermediate product, nitrite, to ruminants necessitate management, as animal poisoning may occur via methemoglobinemia. Certain of the naturally occurring nitrocompounds, such as 3-nitro-1-propionate or 3-nitro-1-propanol also cause poisoning but via inhibition of succinate dehydrogenase. Typical risk management procedures to avoid nitrite toxicity involve gradually adapting the animals to higher concentrations of nitrate and nitrite, which could possibly be used with the nitrocompounds as well. A number of organisms responsible for nitrate metabolism in the rumen have been characterized. To date a

  2. Beta-blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, nitrate-hydralazine, diuretics, aldosterone antagonist, ivabradine, devices and digoxin (BANDAID(2) ): an evidence-based mnemonic for the treatment of systolic heart failure.

    Science.gov (United States)

    Chia, N; Fulcher, J; Keech, A

    2016-06-01

    Heart failure causes significant morbidity and mortality, with recognised underutilisation rates of guideline-based therapies. Our aim was to review current evidence for heart failure treatments and derive a mnemonic summarising best practice, which might assist physicians in patient care. Treatments were identified for review from multinational society guidelines and recent randomised trials, with a primary aim of examining their effects in systolic heart failure patients on mortality, hospitalisation rates and symptoms. Secondary aims were to consider other clinical benefits. MEDLINE and EMBASE were searched using a structured keyword strategy and the retrieved articles were evaluated methodically to produce an optimised reference list for each treatment. We devised the mnemonic BANDAID (2) , standing for beta-blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, nitrate-hydralazine (or potentially neprilysin inhibitor), diuretics, aldosterone antagonist, ivabradine, devices (automatic implantable cardioverter defibrillator, cardiac resynchronisation therapy or both) and digoxin as a representation of treatments with strong evidence for their use in systolic heart failure. Treatment with omega-3 fatty acids, statins or anti-thrombotic therapies has limited benefits in a general heart failure population. Adoption of this mnemonic for current evidence-based treatments for heart failure may help improve prescribing rates and patient outcomes in this debilitating, high mortality condition. © 2016 Royal Australasian College of Physicians.

  3. Characterization of the intracellular and the plasma membrane Ca2+-ATPases in fractionated pig brain membranes using calcium pump inhibitors.

    Science.gov (United States)

    Salvador, J M; Mata, A M

    1998-03-15

    The Ca2+-ATPase activity of isolated membranes and purified plasma membrane ATPase from pig brain was measured in the presence of specific inhibitors. The inhibition of the enzymatic activity by vanadate presents a lower affinity in microsomes than in the synaptic plasma membrane vesicles, showing K0.5 of 0.4 and 0.2 microM, respectively. The purified enzyme showed a higher sensitivity to vanadate with a K0.5 of 0.10 microM. Thapsigargin (Tg) and 2,5-di(tert-butyl)-1,4-benzohydroquinone (BHQ) were stronger inhibitors of the Ca2+-ATPase activity in microsomes than in the synaptic membrane vesicles. The activity of the purified enzyme was not affected by Tg and only partially by BHQ. Cyclopiazonic acid inhibited the enzymatic activity in all fractions, being more sensitive in microsomes. The microsome preparation incorporated 32P from [gamma-32P]ATP into two main proteins that appear at approx 110,000 and 140,000. According to the inhibition pattern, the lower phosphorylated band was identified as the sarco(endo)plasmic reticulum Ca2+-ATPase, being in a higher percentage than the upper band. Synaptic membrane vesicles also incorporated radioactive 32P into two protein bands. The 140,000 protein (upper band) shows the typical behavior of the purified plasma membrane Ca2+-ATPase, being more abundant in this preparation than the organellar Ca2+-pump (lower band). This study highlights the heterogeneous nature of the Ca2+-ATPase activity measured in brain membrane fractions. Copyright 1998 Academic Press.

  4. ω-Tbo-IT1–New Inhibitor of Insect Calcium Channels Isolated from Spider Venom

    Science.gov (United States)

    Mikov, Alexander N.; Fedorova, Irina M.; Potapieva, Natalia N.; Maleeva, Ekaterina E.; Andreev, Yaroslav A.; Zaitsev, Alexey V.; Kim, Kira K.; Bocharov, Eduard V.; Bozin, Timur N.; Altukhov, Dmitry A.; Lipkin, Alexey V.; Kozlov, Sergey A.; Tikhonov, Denis B.; Grishin, Eugene V.

    2015-01-01

    Novel disulfide-containing polypeptide toxin was discovered in the venom of the Tibellus oblongus spider. We report on isolation, spatial structure determination and electrophysiological characterization of this 41-residue toxin, called ω-Tbo-IT1. It has an insect-toxic effect with LD50 19 μg/g in experiments on house fly Musca domestica larvae and with LD50 20 μg/g on juvenile Gromphadorhina portentosa cockroaches. Electrophysiological experiments revealed a reversible inhibition of evoked excitatory postsynaptic currents in blow fly Calliphora vicina neuromuscular junctions, while parameters of spontaneous ones were not affected. The inhibition was concentration dependent, with IC50 value 40 ± 10 nM and Hill coefficient 3.4 ± 0.3. The toxin did not affect frog neuromuscular junctions or glutamatergic and GABAergic transmission in rat brains. Ca2+ currents in Calliphora vicina muscle were not inhibited, whereas in Periplaneta americana cockroach neurons at least one type of voltage gated Ca2+ current was inhibited by ω-Tbo-IT1. Thus, the toxin apparently acts as an inhibitor of presynaptic insect Ca2+ channels. Spatial structure analysis of the recombinant ω-Tbo-IT1 by NMR spectroscopy in aqueous solution revealed that the toxin comprises the conventional ICK fold containing an extended β-hairpin loop and short β-hairpin loop which are capable of making “scissors-like mutual motions”. PMID:26611444

  5. [The effect of ACE inhibitors, beta blockers and calcium antagonists on the responses to pressor stress tests in the elderly hypertensive patients].

    Science.gov (United States)

    Suzuki, Y; Kuwajima, I; Aono, T; Toyoshima, T; Ozawa, T

    1996-01-01

    The purpose of the study was to elucidate the effects of antihypertensive drugs on the hemodynamics in elderly hypertensive patients. Forty-two elderly hypertensives (mean 72 +/- 5 years) were given either ACE inhibitors (A group: perindopril in 10 and captopril in 4 cases), beta blockers (B group: arotinolol in 15 cases) or calcium antagonists (C group: nifedipine in 3 and nitrendipine in 10 cases) for 8-12 weeks. The responses to handgrip and mental arithmetic stress and cardiac functional changes were determined by echocardiography before and after the medications. The decrease in blood pressure at rest and on the stress tests was similar among the three groups, though the hemodynamic responses to the stress tests showed some differences. In the A group, no hemodynamic changes were seen either at rest or on the stress tests after the medication. In the B group, the heart rate and the cardiac output were decreased at rest, and the increase of them on the stress tests were diminished after the medication. On the contrary, the heart rate and the cardiac output were increased, and showed exaggerated responses on the stress tests in the C group. In conclusion, in antihypertensive treatment of elderly hypertensive patients it is important to consider the effects of the antihypertensive drugs on the hemodynamics, although the comparable decrease in blood pressure is expected.

  6. Canine myocardial dihydropyridine binding sites: a positron emission tomographic study with the calcium channel inhibitor 11C-S11568.

    Science.gov (United States)

    Valette, H; Crouzel, C; Syrota, A; Fuseau, C; Bourachot, M L

    1994-01-01

    The in vivo determination of the density of dihydropyridine (DHP) binding sites will allow the assessment of pathophysiological changes associated with heart disease. The calcium channel antagonist S 11568: (+/-)(amino-7 dioxa-2,5 heptyl)-2(dichloro -2,3 phenyl) -4 methyl-6dihydro -1,4 pyridine has an in vitro profile of high potency and of high selectivity for the L-type Ca2+ channel. S 11568 was labelled by a reaction between 11C-diazomethane and the precursor 6-(7-amino-2,5-dioxa heptyl)-4-(2,3-dichloro phenyl)-5-(ethoxycarbonyl)-2 methyl-1,4 dihydro nicotinic acid. (+)-PN 200 110, a DHP with in vitro high affinity for the L-type Ca2+ channel, was also radiolabeled. Positron emission tomographic (PET) studies of both 11C-DHP myocardial uptake were performed in Beagle dogs. 11C-(+)-PN 200 110 had a rapid wash-out from myocardium. In contrary, after a bolus injection, 11C-S 11568 myocardial concentration increased to reach a maximum in 1-2 minutes and then remained in a plateau with a slight downslope while the blood concentration fell rapidly. Myocardial uptake was 2 to 4 fold higher than lung uptake, leading to a good contrast on PET images. Pre-treatment with unlabeled S 11568 (2 mumol/kg or 6 mumol/kg over 15 minutes) reduced myocardial uptake by 60% and 80%, respectively. Specific binding was estimated during a displacement experiment: bolus of unlabeled S 11568: 1 mumol/kg followed by a continuous infusion of 3 mumol/kg over 2 hours. It was found to represent 80% of the total binding. To assess influence of S 11568 on coronary blood flow and therefore on the myocardial tracer delivery, coronary blood flow was measured using 15O-H2O and PET at baseline and following bolus injections of 0.4, 0.8, 2 mumol/kg of S 11568. Only the higher dose increased coronary blood flow. This is the in vivo demonstration of the binding characteristics to myocardial tissue of a DHP ligand. Such properties make S 11568 suitable for PET experiments. The studies of DHP binding

  7. Imidazopyridazine inhibitors of Plasmodium falciparum calcium dependent protein kinase 1 also target cGMP-dependent protein kinase and heat shock protein 90 to kill the parasite at different stages of intracellular development.

    OpenAIRE

    Green, JL; Moon, RW; Whalley, D; Bowyer, PW; Wallace, C.; Rochani, A; Nageshan, RK; Howell, SA; Grainger, M.; Jones, HM; Ansell, KH; Chapman, TM; Taylor, DL; Osborne, SA; Baker, DA

    2015-01-01

    : Imidazopyridazine compounds are potent, ATP-competitive inhibitors of calcium-dependent protein kinase 1 (CDPK1) and of Plasmodium falciparum parasite growth in vitro. Here, we show that these compounds can be divided into two classes depending on the nature of the aromatic linker between the core and the R2 substituent group. Class 1 compounds have a pyrimidine linker and inhibit parasite growth at late schizogony, whereas class 2 compounds have a nonpyrimidine linker and inhibit growth in...

  8. Effect of nitrate on microbial perchlorate reduction

    Science.gov (United States)

    Sun, Y.; Coates, J. D.

    2007-12-01

    nitrate, transcripts of perchlorate reductase and chlorite dismutase were analyzed to determine possible transcriptional regulation from nitrate. During growth transition studies, increase in the level of transcripts necessary for nitrate reduction and perchlorate reduction was observed concomitantly with decrease in the concentration of nitrate and perchlorate respectively suggesting transcriptional regulation was involved in the preferential utilization of nitrate and that nitrate might be a transcriptional inhibitor of perchlorate reduction. Again, using non-growth washed cell suspensions of perchlorate grown D. aromatica, a decrease of transcript level of the perchlorate reductase but not the chlorite dismutase was observed after incubation with nitrate. In conclusion, from physiological and molecular evidence, nitrate negatively regulates transcription of perchlorate reductase thus inhibiting perchlorate reduction. This result is unexpected as it is in contrast to the accepted dogma that microorganisms regulate their metabolisms to utilize electron acceptors in a sequential manner based on thermodynamic optimization which would imply that perchlorate should be used preferentially to nitrate.

  9. The Effect of a Novel Highly Selective Inhibitor of the Sodium/Calcium Exchanger (NCX) on Cardiac Arrhythmias in In Vitro and In Vivo Experiments.

    Science.gov (United States)

    Kohajda, Zsófia; Farkas-Morvay, Nikolett; Jost, Norbert; Nagy, Norbert; Geramipour, Amir; Horváth, András; Varga, Richárd S; Hornyik, Tibor; Corici, Claudia; Acsai, Károly; Horváth, Balázs; Prorok, János; Ördög, Balázs; Déri, Szilvia; Tóth, Dániel; Levijoki, Jouko; Pollesello, Piero; Koskelainen, Tuula; Otsomaa, Leena; Tóth, András; Baczkó, István; Leprán, István; Nánási, Péter P; Papp, Julius Gy; Varró, András; Virág, László

    2016-01-01

    In this study the effects of a new, highly selective sodium-calcium exchanger (NCX) inhibitor, ORM-10962 were investigated on cardiac NCX current, Ca2+ transients, cell shortening and in experimental arrhythmias. The level of selectivity of the novel inhibitor on several major transmembrane ion currents (L-type Ca2+ current, major repolarizing K+ currents, late Na+ current, Na+/K+ pump current) was also determined. Ion currents in single dog ventricular cells (cardiac myocytes; CM), and action potentials in dog cardiac multicellular preparations were recorded utilizing the whole-cell patch clamp and standard microelectrode techniques, respectively. Ca2+ transients and cell shortening were measured in fluorescent dye loaded isolated dog myocytes. Antiarrhythmic effects of ORM-10962 were studied in anesthetized ouabain (10 μg/kg/min i.v.) pretreated guinea pigs and in ischemia-reperfusion models (I/R) of anesthetized coronary artery occluded rats and Langendorff perfused guinea pigs hearts. ORM-10962 significantly reduced the inward/outward NCX currents with estimated EC50 values of 55/67 nM, respectively. The compound, even at a high concentration of 1 μM, did not modify significantly the magnitude of ICaL in CMs, neither had any apparent influence on the inward rectifier, transient outward, the rapid and slow components of the delayed rectifier potassium currents, the late and peak sodium and Na+/K+ pump currents. NCX inhibition exerted moderate positive inotropic effect under normal condition, negative inotropy when reverse, and further positive inotropic effect when forward mode was facilitated. In dog Purkinje fibres 1 μM ORM-10962 decreased the amplitude of digoxin induced delayed afterdepolarizations (DADs). Pre-treatment with 0.3 mg/kg ORM-10962 (i.v.) 10 min before starting ouabain infusion significantly delayed the development and recurrence of ventricular extrasystoles (by about 50%) or ventricular tachycardia (by about 30%) in anesthetized guinea pigs

  10. Angiotensin Converting-Enzyme Inhibitors, Angiotensin Receptor Blockers, and Calcium Channel Blockers Are Associated with Prolonged Vascular Access Patency in Uremic Patients Undergoing Hemodialysis.

    Directory of Open Access Journals (Sweden)

    Fu-An Chen

    Full Text Available Vascular access failure is a huge burden for patients undergoing hemodialysis. Many efforts have been made to maintain vascular access patency, including pharmacotherapy. Angiotensin converting enzyme inhibitor (ACE-I, angiotensin receptor blocker (ARB, and calcium channel blocker (CCB are known for their antihypertensive and cardio-protective effects, however, their effects on long-term vascular access patency are still inconclusive.We retrospectively enrolled patients commencing maintenance hemodialysis between January 1, 2000, and December 31, 2006 by using National Health Insurance Research Database in Taiwan. Primary patency was defined as the date of first arteriovenous fistula (AVF or arteriovenous graft (AVG creation to the time of access thrombosis or any intervention aimed to maintain or re-establish vascular access patency. Cox proportional hazards models were used to adjust the influences of patient characteristics, co-morbidities and medications.Total 42244 patients were enrolled in this study, 37771 (89.4% used AVF, 4473 (10.6% used AVG as their first long term dialysis access. ACE-I, ARB, and CCB use were all associated with prolonged primary patency of AVF [hazard ratio (HR 0.586, 95% confidence interval (CI 0.557-0.616 for ACE-I use; HR 0.532, CI 0.508-0.556 for ARB use; HR 0.485, CI 0.470-0.501 for CCB use] and AVG (HR 0.557, CI 0.482-0.643 for ACE-I use, HR 0.536, CI 0.467-0.614 for ARB use, HR 0.482, CI 0.442-0.526 for CCB use.In our analysis, ACE-I, ARB, and CCB were strongly associated with prolonged primary patency of both AVF and AVG. Further prospective randomized studies are still warranted to prove the causality.

  11. Optimisation and validation of a high throughput screening compatible assay to identify inhibitors of the plasma membrane calcium ATPase pump--a novel therapeutic target for contraception and malaria.

    Science.gov (United States)

    Mohamed, Tamer M A; Zakeri, Simon A; Baudoin, Florence; Wolf, Markus; Oceandy, Delvac; Cartwright, Elizabeth J; Gul, Sheraz; Neyses, Ludwig

    2013-01-01

    ATPases, which constitute a major category of ion transporters in the human body, have a variety of significant biological and pathological roles. However, the lack of high throughput assays for ATPases has significantly limited drug discovery in this area. We have recently found that the genetic deletion of the ATP dependent calcium pump PMCA4 (plasma membrane calcium/calmodulin dependent ATPase, isoform 4) results in infertility in male mice due to a selective defect in sperm motility. In addition, recent discoveries in humans have indicated that a single nucleotide polymorphism (SNP) in the PMCA4 gene determines the susceptibility towards malaria plasmodium infection. Therefore, there is an urgent need to develop specific PMCA4 inhibitors. In the current study, we aim to optimise and validate a high throughput screening compatible assay using recombinantly expressed PMCA4 and the HTRF® Transcreener® ADP (TR-FRET) assay to screen a drug library. PMCA4 membrane microsomes were prepared from HEK293 cells overexpressing PMCA4. Western blot quantification revealed nearly nine-fold increased expression of PMCA4 compared to LacZ (control virus)-infected cells. Maximal PMCA4 microsomal activity was achieved in the TR-FRET assay with 15ng/μl microsomal concentration, 30-minute pre-incubation with compounds at 37°C, and calcium buffering with 1mM EGTA providing 1μM free-calcium. Finally a dose-response curve for carboxyeosin (a non-specific PMCA inhibitor) under optimised conditions showed significant PMCA4 inhibition. Upon confirmation that the assay was suitable for high-throughput screening, we have screened the ChemBioNet small molecule library (~21,000 compounds) against the PMCA4 assay to identify those that are its apparent inhibitors. This screening yielded 1,494 primary hits. We have optimised the HTRF® Transcreener® ADP assay for high-throughput screening to identify PMCA4 inhibitors. The output of the screening campaign has provided preliminary chemical

  12. Calcium - urine

    Science.gov (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 ...

  13. Nitrate removal using natural clays modified by acid thermoactivation

    Science.gov (United States)

    Mena-Duran, C. J.; Sun Kou, M. R.; Lopez, T.; Azamar-Barrios, J. A.; Aguilar, D. H.; Domínguez, M. I.; Odriozola, J. A.; Quintana, P.

    2007-04-01

    Groundwater pollution by nitrates is a widespread problem in many locations in the world. The underground aquatic mantle of the Peninsula of Yucatan is highly vulnerable due to its karstic nature. Adsorption methods are a good choice for nitrate elimination. In this work, a natural calcium bentonite was modified by acid thermoactivation with HCl and H 2SO 4, and tested as a media for nitrate removal in an aqueous solution. The nitrate concentration in the solution was measured by FT-IR, using the Lambert-Beer law. Clay characterization was carried out by X-ray diffraction and FT-IR spectroscopy; surface area was measured by the BET method.

  14. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  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

    2017-10-01

    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. Ipso Nitration. Regiospecific Nitration via Ipso Nitration Products.

    Science.gov (United States)

    1985-05-20

    borohydride in methanol followed by vacuum evaporation and low temperature liquid-liquid extraction . As a com- plementary method, means of preparing 1,4...or phenyl acetate. The reaction is formally an elimination of the elements of nitrous acid and has been characterized as an El-like elimination...diastereomeric adducts formed by nitration of furfural diacetate and methyl furoate with acetyl nitrate. The solvolytic chemistry of these adducts has been

  17. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate and potassium nitrate. 181.33...-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions issued by the U.S. Department of Agriculture for use as sources of...

  18. Nitrate accumulation in spinach

    NARCIS (Netherlands)

    Steingröver, Eveliene Geertruda

    1986-01-01

    Leafy vegetables, like spinach, may contain high concentrations of nitrate. In the Netherlands, about 75% of mean daily intake of nitrate orginates from the consumption of vegatables. Hazards to human health are associated with the reduction of nitrate to nitrite. Acute nitrite poisoning causes

  19. Combination of low calcium with Y-27632 rock inhibitor increases the proliferative capacity, expansion potential and lifespan of primary human keratinocytes while retaining their capacity to differentiate into stratified epidermis in a 3D skin model.

    Directory of Open Access Journals (Sweden)

    Xanthe L Strudwick

    Full Text Available Human keratinocytes are difficult to isolate and have a limited lifespan. Traditionally, immortalised keratinocyte cell lines are used in vitro due to their ability to bypass senescence and survive indefinitely. However these cells do not fully retain their ability to differentiate in vitro and they are unable to form a normal stratum corneum in organotypic culture. Here we aimed to generate a pool of phenotypically similar keratinocytes from human donors that could be used in monolayer culture, without a fibroblast feeder layer, and in 3D human skin equivalent models. Primary human neonatal epidermal keratinocytes (HEKn were cultured in low calcium, (0.07 mM media, +/-10 μM Y-27632 ROCK inhibitor (HEKn-CaY. mRNA and protein was extracted and expression of differentiation markers Keratin 14 (K14, Keratin 10 (K10 and Involucrin (Inv assessed by qRT-PCR and Western blotting. The differentiation potential of the HEKn-CaY cultures was assessed by increasing calcium levels and removing the Y-27632 for 72 hrs prior to assessment of K14, K10 and Inv. The ability of the HEKn-CaY, to form a stratified epithelium was assessed using a human skin equivalent (HSE model in the absence of Y-27632. Increased proliferative capacity, expansion potential and lifespan of HEKn was observed with the combination of low calcium and 10 μM ROCK inhibitor Y-27632. The removal of Y-27632 and the addition of high calcium to induce differentiation allowed the cells to behave as primary keratinocytes even after extended serial passaging. Prolonged lifespan HEK-CaYs were capable of forming an organised stratified epidermis in 3D HSE cultures, demonstrating their ability to fully stratify and retain their original, primary characteristics. In conclusion, the use of 0.07 mM Calcium and 10 μM Y-27632 in HEKn monocultures provides the opportunity to culture primary human keratinocytes without a cell feeder layer for extended periods of culture whilst retaining their ability to

  20. Ammonium nitrate explosion hazards

    Directory of Open Access Journals (Sweden)

    Negovanović Milanka

    2015-01-01

    Full Text Available Ammonium nitrate (AN primarily is used as a fertilizer but it is also very important compound in the production of industrial explosives. The application of ammonium nitrate in the production of industrial explosives was related with the early era of Nobel dynamite and widely increased with the appearance of blasting agents such as ANFO and Slurry, in the middle of the last Century. Throughout the world millions of tons of ammonium nitrate are produced annually and handled without incident. Although ammonium nitrate generally is used safely, accidental explosions involving AN have high impact resulting in loss of lives and destruction of property. The paper presents the basic properties of ammonium nitrate as well as hazards in handling of ammonium nitrate in order to prevent accidents. Several accidents with explosions of ammonium nitrate resulted in catastrophic consequences are listed in the paper as examples of non-compliance with prescribed procedures.

  1. Calcium Carbonate

    Science.gov (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 ...

  2. Calcium supplements

    Science.gov (United States)

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

  3. Influence of calcium sources on microbially induced calcium carbonate precipitation by Bacillus sp. CR2.

    Science.gov (United States)

    Achal, Varenyam; Pan, Xiangliang

    2014-05-01

    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.

  4. Nitrogen uptake by heterotrophic bacteria and phytoplankton in the nitrate-rich Thames estuary

    OpenAIRE

    J. J. Middelburg; Nieuwenhuize, J.

    2000-01-01

    The uptake of ammonium, nitrate, amino acids and urea was examined in the nitrate-rich Thames estuary and adjacent area in the North Sea during February 1999. The majority of uptake was by heterotrophic bacteria, as demonstrated by addition of a prokaryotic inhibitor that lowered uptake rates by 82, 66, 49 and 86 % for ammonium, nitrate, amino acids and urea, respectively. Amino acids were preferred over ammonium and urea, which in turn were preferred over nitrate. Urea was not important as n...

  5. Intercomparison 9812. pH, conductivity, alkalinity, nitrate + nitrite, chloride, sulfate, calcium, magnesium, sodium, potassium, total aluminium, reactive and non-labile aluminium, dissolved organic carbon, and chemical oxygen demand (ICP Waters report 49/1998)

    OpenAIRE

    Hovind, H.

    1998-01-01

    43 laboratories in 20 countries participated in intercomparison 9812. One sample set for the determination of major ions, organic matter and aluminium fractions, were used. Based on the general target accuracy of * 20 %, 74 % of the results were acceptable. More than 80 % of the result pairs were acceptable for conductivity, nitrate + nitrite, sulfate, sodium, and dissolved organic carbon. For pH only 55 % of the result pairs were acceptable in relation to the extended target accuracy of * 0....

  6. Genetic basis for nitrate resistance in Desulfovibrio strains

    Directory of Open Access Journals (Sweden)

    Hannah eKorte

    2014-04-01

    Full Text Available Nitrate is an inhibitor of sulfate-reducing bacteria (SRB. In petroleum production sites, amendments of nitrate and nitrite are used to prevent SRB production of sulfide that causes souring of oil wells. A better understanding of nitrate stress responses in the model SRB, Desulfovibrio vulgaris Hildenborough and Desulfovibrio alaskensis G20, will strengthen predictions of environmental outcomes. Nitrate inhibition of SRB has historically been considered to result from the generation of small amounts of nitrite, to which SRB are quite sensitive. Here we explored the possibility that nitrate might inhibit SRB by a mechanism other than through nitrite inhibition. We found that nitrate-stressed D. vulgaris cultures grown in lactate-sulfate conditions eventually grew in the presence of high concentrations of nitrate, and their resistance continued through several subcultures. Nitrate consumption was not detected over the course of the experiment, suggesting adaptation to nitrate. With high-throughput genetic approaches employing TnLE-seq for D. vulgaris and a pooled mutant library of D. alaskensis, we determined the fitness of many transposon mutants of both organisms in nitrate stress conditions. We found that several mutants, including homologs present in both strains, had a greatly increased ability to grow in the presence of nitrate but not nitrite. The mutated genes conferring nitrate resistance included the gene encoding the putative Rex transcriptional regulator (DVU0916/Dde_2702, as well as a cluster of genes (DVU0251-DVU0245/Dde_0597-Dde_0605 that is poorly annotated. Follow-up studies with individual D. vulgaris transposon and deletion mutants confirmed high-throughput results. We conclude that, in D. vulgaris and D. alaskensis, nitrate resistance in wild-type cultures is likely conferred by spontaneous mutations. Furthermore, the mechanisms that confer nitrate resistance may be different from those that confer nitrite resistance.

  7. Beyond-root calcium fertilization of apple trees

    Directory of Open Access Journals (Sweden)

    Kazimierz Słowik

    2013-12-01

    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.

  8. Cloning and nitrate induction of nitrate reductase mRNA

    OpenAIRE

    Cheng, Chi-Lien; Dewdney, Julia; Kleinhofs, Andris; Goodman, Howard M.

    1986-01-01

    Nitrate is the major source of nitrogen taken from the soil by higher plants but requires reduction to ammonia prior to incorporation into amino acids. The first enzyme in the reducing pathway is a nitrate-inducible enzyme, nitrate reductase (EC 1.6.6.1). A specific polyclonal antiserum raised against purified barley nitrate reductase has been used to immunoprecipitate in vivo labeled protein and in vitro translation products, demonstrating that nitrate induction increases nitrate reductase p...

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

    OpenAIRE

    Hovind, H.

    1997-01-01

    47 laboratories in 22 countries participated in intercomparison 9711. One sample set for the determination of major ions, organic matter and aluminium fractions, were used. Based on the general target accuracy of + 20%, 78% of the results were acceptable. More than 80% of the result pairs were acceptable for chloride, sulfate, calcium, mangnesium, sodium, dissolved organic carbon and chemical oxygen demand. For pH only 43% of the result pairs were acceptable in relation to the extended target...

  10. Effects of free air carbon dioxide enrichment (FACE) on nitrogen assimilation and growth of winter wheat under nitrate and ammonium fertilization.

    Science.gov (United States)

    Dier, Markus; Meinen, Rieke; Erbs, Martin; Kollhorst, Lena; Baillie, Christin-Kirsty; Kaufholdt, David; Kücke, Martin; Weigel, Hans-Joachim; Zörb, Christian; Hänsch, Robert; Manderscheid, Remy

    2018-01-01

    A 2-year Free Air CO 2 Enrichment (FACE) experiment was conducted with winter wheat. It was investigated whether elevated atmospheric CO 2 concentration (e[CO 2 ]) inhibit nitrate assimilation and whether better growth and nitrogen acquisition under e[CO 2 ] can be achieved with an ammonium-based fertilization as it was observed in hydroponic culture with wheat. Under e[CO 2 ] a decrease in nitrate assimilation has been discussed as the cause for observed declines in protein concentration in C 3 cereals. Wheat was grown under ambient [CO 2 ] and e[CO 2 ] (600 ppm) with three levels (deficiency, optimal, and excessive) of nitrate-based fertilization (calcium ammonium nitrate; CAN) or with optimal ammonium-based fertilization. Ammonium fertilization was applied via injection of an ammonium solution into the soil in the 1st year and by surface application of urea combined with nitrification inhibitors (UNI) in the 2nd year. Results showed that ammonium-based fertilization was successfully achieved in the 2nd year with respect to nitrification control, as soil ammonium concentration was considerably higher over the growing season for UNI fertilized plots compared to optimal CAN plots. Also, stem nitrate concentration, flag leaf nitrate reductase activity, and transcript levels were lower in UNI fertilized plants compared to optimal CAN. Regarding the e[CO 2 ] effect on nitrate reductase activity and transcript levels, no alteration could be observed for any nitrogen fertilizer treatment. Flag leaf growth was stimulated under e[CO 2 ] leading to an enhanced nitrate reductase activity referred to m 2 ground area at late flowering being in line with a higher nitrogen acquisition under e[CO 2 ]. Moreover, nitrogen acquisition was considerably higher in nitrate fertilized plants compared to ammonium fertilized plants under e[CO 2 ]. Our results obtained under field conditions show that a change from nitrate- to ammonium-based fertilization will not lead to a better growth

  11. Enhanced expression of a calcium-dependent protein kinase from ...

    Indian Academy of Sciences (India)

    Unknown

    low calcium medium; LNM, low nitrate medium; LPM, low phosphate medium; LSM, low sulphate medium; MMG, minimal medium with glucose; NR, nitrate ... processes like pollen tube growth (Picton and Steer 1983) and cytokinin induced bud ... melanogaster and Saccharomyces cerevisiae. The CDPK genes are highly ...

  12. Calcium-dependent, interleukin 1-converting enzyme inhibitor-insensitive degradation of lamin B1 and DNA fragmentation in isolated thymocyte nuclei.

    Science.gov (United States)

    McConkey, D J

    1996-09-13

    Recent work suggests that the proteolytic degradation of the nuclear lamins is a common event in apoptosis, although the nature of the proteases involved is still not clear. Our previous work showed that the degradation of lamin B1 in glucocorticoid-treated thymocytes occurs via a Ca2+-sensitive mechanism and that exogenous Ca2+ promotes lamin degradation in isolated thymocyte nuclei from untreated cells. Here we demonstrate that peptide-based inhibitors of the interleukin 1beta-converting enzyme family of cysteine proteases (Tyr-Val-Ala-Asp fluoromethyl ketone) and of the nuclear scaffold multicatalytic proteinase (Ala-Pro-Phe chloromethyl ketone) block the degradation of lamin B1 to a 21-kDa fragment in thymocytes treated with glucocorticoid, the Ca2+-mobilizing agent thapsigargin, or antibodies to the T cell receptor. However, among a panel of inhibitors specific for several different proteases implicated in apoptosis, only tosylphenylalanyl chloromethyl ketone and the nuclear scaffold protease inhibitor block lamin degradation, histone H1 cleavage, and DNA fragmentation in isolated thymocyte nuclei incubated with Ca2+. Overexpression of human BCL-2 in nuclei by stable transfection resulted in an inhibition of Ca2+-stimulated lamin degradation and DNA fragmentation, suggesting that endogenous nuclear BCL-2 regulates activation of the nuclear scaffold protease. The results demonstrate the existence of an alternative pathway of lamin degradation and DNA fragmentation mediated by a resident Ca2+-stimulated nuclear protease that is not directly dependent upon activation of the interleukin 1beta-converting enzyme family of cell death regulators.

  13. Why do hypertensive patients of African ancestry respond better to calcium blockers and diuretics than to ACE inhibitors and β-adrenergic blockers? A systematic review

    Science.gov (United States)

    2013-01-01

    Background Clinicians are encouraged to take an individualized approach when treating hypertension in patients of African ancestry, but little is known about why the individual patient may respond well to calcium blockers and diuretics, but generally has an attenuated response to drugs inhibiting the renin-angiotensin system and to β-adrenergic blockers. Therefore, we systematically reviewed the factors associated with the differential drug response of patients of African ancestry to antihypertensive drug therapy. Methods Using the methodology of the systematic reviews narrative synthesis approach, we sought for published or unpublished studies that could explain the differential clinical efficacy of antihypertensive drugs in patients of African ancestry. PUBMED, EMBASE, LILACS, African Index Medicus and the Food and Drug Administration and European Medicines Agency databases were searched without language restriction from their inception through June 2012. Results We retrieved 3,763 papers, and included 72 reports that mainly considered the 4 major classes of antihypertensive drugs, calcium blockers, diuretics, drugs that interfere with the renin-angiotensin system and β-adrenergic blockers. Pharmacokinetics, plasma renin and genetic polymorphisms did not well predict the response of patients of African ancestry to antihypertensive drugs. An emerging view that low nitric oxide and high creatine kinase may explain individual responses to antihypertensive drugs unites previous observations, but currently clinical data are very limited. Conclusion Available data are inconclusive regarding why patients of African ancestry display the typical response to antihypertensive drugs. In lieu of biochemical or pharmacogenomic parameters, self-defined African ancestry seems the best available predictor of individual responses to antihypertensive drugs. PMID:23721258

  14. Agricultural nitrate pollution

    DEFF Research Database (Denmark)

    Anker, Helle Tegner

    2015-01-01

    Despite the passing of almost 25 years since the adoption of the EU Nitrates Directive, agricultural nitrate pollution remains a major concern in most EU Member States. This is also the case in Denmark, although a fairly strict regulatory regime has resulted in almost a 50 per cent reduction...... in nitrogen leaching since the mid-80s. Nevertheless, further effort is needed, particularly in ecologically sensitive areas. This article discusses different regulatory approaches – and in particular the need for a differentiated nitrate regulation tailored to meet site-specific ecological demands – from...... of the mandatory specification standards of the Nitrates Directive combined with additional instruments to address the need for severe restrictions on fertiliser use or cultivation practices in the most ecologically vulnerable areas....

  15. A novel Glycine soja cysteine proteinase inhibitor GsCPI14, interacting with the calcium/calmodulin-binding receptor-like kinase GsCBRLK, regulated plant tolerance to alkali stress.

    Science.gov (United States)

    Sun, Xiaoli; Yang, Shanshan; Sun, Mingzhe; Wang, Sunting; Ding, Xiaodong; Zhu, Dan; Ji, Wei; Cai, Hua; Zhao, Chaoyue; Wang, Xuedong; Zhu, Yanming

    2014-05-01

    It has been well demonstrated that cystatins regulated plant stress tolerance through inhibiting the cysteine proteinase activity under environmental stress. However, there was limited information about the role of cystatins in plant alkali stress response, especially in wild soybean. Here, in this study, we focused on the biological characterization of a novel Glycine soja cystatin protein GsCPI14, which interacted with the calcium/calmodulin-binding receptor-like kinase GsCBRLK and positively regulated plant alkali stress tolerance. The protein-protein interaction between GsCBRLK and GsCPI14 was confirmed by using split-ubiquitin based membrane yeast two-hybrid analysis and bimolecular fluorescence complementation assay. Expression of GsCPI14 was greatly induced by salt, ABA and alkali stress in G. soja, and GsCBRLK overexpression (OX) in Glycine max promoted the stress induction of GmCPI14 expression under stress conditions. Furthermore, we found that GsCPI14-eGFP fusion protein localized in the entire Arabidopsis protoplast and onion epidermal cell, and GsCPI14 showed ubiquitous expression in different tissues of G. soja. In addition, we gave evidence that the GST-GsCPI14 fusion protein inhibited the proteolytic activity of papain in vitro. At last, we demonstrated that OX of GsCPI14 in Arabidopsis promoted the seed germination under alkali stress, as evidenced by higher germination rates. GsCPI14 transgenic Arabidopsis seedlings also displayed better growth performance and physiological index under alkali stress. Taken together, results presented in this study demonstrated that the G. soja cysteine proteinase inhibitor GsCPI14 interacted with the calcium/calmodulin-binding receptor-like kinase GsCBRLK and regulated plant tolerance to alkali stress.

  16. Nitrate in groundwater of the United States, 1991-2003

    Science.gov (United States)

    Burow, Karen R.; Nolan, Bernard T.; Rupert, Michael G.; Dubrovsky, Neil M.

    2010-01-01

    An assessment of nitrate concentrations in groundwater in the United States indicates that concentrations are highest in shallow, oxic groundwater beneath areas with high N inputs. During 1991-2003, 5101 wells were sampled in 51 study areas throughout the U.S. as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) program. The well networks reflect the existing used resource represented by domestic wells in major aquifers (major aquifer studies), and recently recharged groundwater beneath dominant land-surface activities (land-use studies). Nitrate concentrations were highest in shallow groundwater beneath agricultural land use in areas with well-drained soils and oxic geochemical conditions. Nitrate concentrations were lowest in deep groundwater where groundwater is reduced, or where groundwater is older and hence concentrations reflect historically low N application rates. Classification and regression tree analysis was used to identify the relative importance of N inputs, biogeochemical processes, and physical aquifer properties in explaining nitrate concentrations in groundwater. Factors ranked by reduction in sum of squares indicate that dissolved iron concentrations explained most of the variation in groundwater nitrate concentration, followed by manganese, calcium, farm N fertilizer inputs, percent well-drained soils, and dissolved oxygen. Overall, nitrate concentrations in groundwater are most significantly affected by redox conditions, followed by nonpoint-source N inputs. Other water-quality indicators and physical variables had a secondary influence on nitrate concentrations.

  17. Calcium Signaling Pathway Is Associated with the Long-Term Clinical Response to Selective Serotonin Reuptake Inhibitors (SSRI and SSRI with Antipsychotics in Patients with Obsessive-Compulsive Disorder.

    Directory of Open Access Journals (Sweden)

    Hidehiro Umehara

    Full Text Available Selective serotonin reuptake inhibitors (SSRI are established first-line pharmacological treatments for obsessive-compulsive disorder (OCD, while antipsychotics are used as an augmentation strategy for SSRI in OCD patients who have either no response or a partial response to SSRI treatment. The goal of the present study was to identify genetic variants and pathways that are associated with the long-term clinical response of OCD patients to SSRI or SSRI with antipsychotics.We first performed a genome-wide association study of 96 OCD patients to examine genetic variants contributing to the response to SSRI or SSRI with antipsychotics. Subsequently, we conducted pathway-based analyses by using Improved Gene Set Enrichment Analysis for Genome-wide Association Study (i-GSEA4GWAS to examine the combined effects of genetic variants on the clinical response in OCD.While we failed to detect specific genetic variants associated with clinical responses to SSRI or to SSRI with an atypical antipsychotic at genome-wide levels of significance, we identified 8 enriched pathways for the SSRI treatment response and 5 enriched pathways for the treatment response to SSRI with an antipsychotic medication. Notably, the calcium signaling pathway was identified in both treatment responses.Our results provide novel insight into the molecular mechanisms underlying the variability in clinical response to SSRI and SSRI with antipsychotics in OCD patients.

  18. Management of Microbial Nitrate Production in Agricultural Soils

    OpenAIRE

    Shi, Wei

    1998-01-01

    Nitrate (NO3-) is of central importance in the internal soil nitrogen (N) cycle. While animal wastes and nitrification inhibitors have been used in modern agriculture for decades, their effects on soil NO3- production in relation to ammonium (NH4+) availability and nitrifier population activity in agricultural soils receiving animal wastes or nitrification inhibitors. Several laboratory and field studies assessed the impacts of variously treated dairy wastes and the effects of repeated lon...

  19. Nitrogen uptake by heterotrophic bacteria and phytoplankton in the nitrate-rich Thames estuary

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.

    2000-01-01

    The uptake of ammonium, nitrate, amino acids and urea was examined in the nitrate-rich Thames estuary and adjacent area in the North Sea during February 1999. The majority of uptake was by heterotrophic bacteria, as demonstrated by addition of a prokaryotic inhibitor that lowered uptake rates by 82,

  20. Nitration of petroleum porphyrins

    Energy Technology Data Exchange (ETDEWEB)

    Sailova, R.V.; Aksenov, V.S.; Isobayev, M.D.; Numanov, I.U.

    1983-01-01

    The reaction of nitration of demetallized porphyrins (Pr) from oils from the Kichik Bel deposit is studied and an attempt is made to evaluate the reactivity of the meso and pyrrole positions in the porphyrine system and to note the ways to produce new, promising chemical substances on the basis of the oil. The fractions isolated and chromatographically purified were analyzed through an electron absorption spectroscopy method. The demetallization of the vanadylporphyrines was conducted by orthophosphoric acid. A concentrate of demetallized porphyrines, liberated from impurities through a method of tower chromatography in Al203, was used for the nitration. A number of nitrating agents were tested, including concentrated HNO3, HNO3 plus CH5COOH (polar), HNO3 plus H2SO4. A proton magnetic resonance (PMR) and spectroscopic method showed that a mole of the porphyrines in the concentrate on the average contains 2 pyrrole and 3 to 4 unsubstituted mesopositions.

  1. Yttrium Nitrate mediated Nitration of Phenols at room temperature in ...

    Indian Academy of Sciences (India)

    Rapid nitration of electron rich phenols using Y(NO₃)₃.6H₂O in glacial acetic acid at room temperature was observed with good yield. The method allows nitration of phenols without oxidation, and isolation of nitration product in a rapid and simple way. The described method is selective for phenols.

  2. 4-Methoxyanilinium nitrate

    Directory of Open Access Journals (Sweden)

    Hajer Rahmouni

    2011-09-01

    Full Text Available The title compound, C7H10NO+·NO3−, crystallized with two p-ansidinium cations and two nitrate anions in the asymmetric unit. As well as Columbic and van der Waals forces, moleucles interact via multiple bifurcated N—H...O hydrogen bonds that help consolidate the crystal packing, resulting in a three-dimensional network.

  3. Bioactivity studies of calcium magnesium silicate prepared from eggshell waste by sol–gel combustion synthesis

    Directory of Open Access Journals (Sweden)

    Rajan Choudhary

    2015-06-01

    Full Text Available The present study focused on the synthesis of calcium magnesium silicate (akermanite, Ca2MgSi2O7 using eggshell biowaste (as calcium source, magnesium nitrate and tetraethyl orthosilicate (TEOS as starting materials. Sol–gel combustion method was adopted to obtain calcium magnesium silicate. Citric acid was used as a fuel (reducing agent and nitrate ions present in the metal nitrates acts as an oxidizing agent during combustion process. The characterization of synthesized calcium magnesium silicate was carried out by powder X-ray diffraction (XRD, Fourier transform infrared (FTIR and scanning electron microscopy (SEM techniques. Calcium magnesium silicate crystallite size was observed in nano regime which can effectively mimic natural bone apatite composition. In-vitro bioactivity was investigated by immersing calcium magnesium silicate pellet in simulated body fluid (SBF for three weeks. Results show effective deposition of crystallized hydroxyapatite (HAP layer on its surface and predicting its possibilities for applications in hard tissue regeneration.

  4. Calcium Electroporation

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  5. Diuretics and disorders of calcium homeostasis.

    Science.gov (United States)

    Grieff, Marvin; Bushinsky, David A

    2011-11-01

    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.

  6. 4-Methoxybenzylammonium nitrate

    Directory of Open Access Journals (Sweden)

    P. Umarani

    2017-08-01

    Full Text Available In the title salt, C8H12NO+·NO3−, the 4-methoxybenzylammonium cation lies in the mirror plane m of space group Pnma and is thus planar by symmetry. The nitrate anion is also planar by symmetry, with an N...;O group in the mirror plane and one O atom in a general position. The dihedral angle between the benzene ring and the planar nitrate anion is constrained to be exactly 90°, because of the relative special positions for both ions. In the crystal, the cations are connected to the anions by C—H...O, C—H...N, N—H...N and N—H...O hydrogen bonds. Further, the crystal structure also features two C—H...π interactions involving the benzene ring of the cation, forming a three-dimensional network.

  7. Nitrate in drinking water

    DEFF Research Database (Denmark)

    Schullehner, Jörg; Hansen, Birgitte; Sigsgaard, Torben

    Annual nationwide exposure maps for nitrate in drinking water in Denmark from the 1970s until today will be presented based on the findings in Schullehner & Hansen (2014) and additional work on addressing the issue of private well users and estimating missing data. Drinking water supply in Denmark...... is highly decentralized and fully relying on simple treated groundwater. At the same time, Denmark has an intensive agriculture, making groundwater resources prone to nitrate pollution. Drinking water quality data covering the entire country for over 35 years are registered in the public database Jupiter....... In order to create annual maps of drinking water quality, these data had to be linked to 2,852 water supply areas, which were for the first time digitized, collected in one dataset and connected to the Jupiter database. Analyses of the drinking water quality maps showed that public water supplies...

  8. Nitrates and nitrites intoxications’ management

    Directory of Open Access Journals (Sweden)

    Alexandra Trif

    2007-12-01

    Full Text Available The study pointed out the major sources for clinical and subclinical intoxications with nitrates/nitrites (drinking water and nitrates containing fertilizers, circumstances that determine fertilizers to became sources of intoxication (excessive fertilization/consecutive high level of nitrates in fodders, free access of animals to the fertilizers, administration into the diet instead of natrium chloride, factors that determine high nitrates accumulation in fodders despite optimal fertilization (factors related to the plants, soil, clime, harvest methods, storage, agrotechnical measures, nitrates/nitrites toxicity (over 45 ppm nitrates in drinking water, over 0.5 g nitrate/100 g D.M fodder/diet, the factors that influence nitrates/nitrites toxicity ( species, age, rate of feeding, diet balance especially energetically, pathological effects and symptoms (irritation and congestions on digestive tract, resulting diarrhoea, transformation of hemoglobin into methemoglobin determining severe respiratory insufficiency, vascular collapse, low blood pressure inthe acute nitrates intoxication; hypotiroidism, hypovitaminosis A, reproductive disturbances(abortion, low rate of fertility, dead born offspring, diarrhoea and/or respiratory insufficiency in new born e.g. calves, immunosuppression, decrease of milk production in chronic intoxication. There were presented some suggestions concerning management practices to limit nitrate intoxication (analyze of nitrates/nitrites in water and fodders, good management of the situation of risk ,e .g. dilution of the diet with low nitrate content fodders, feeding with balanced diet in energy, protein, minerals and vitamins, accommodation to high nitrate level diet, avoid grazing one week after a frost period, avoid feeding chop green fodders stored a couple of days, monitoring of health status of animals fed with fodders containing nitrates at risk level, a.o..

  9. Nitrate biosensors and biological methods for nitrate determination.

    Science.gov (United States)

    Sohail, Manzar; Adeloju, Samuel B

    2016-06-01

    The inorganic nitrate (NO3‾) anion is present under a variety of both natural and artificial environmental conditions. Nitrate is ubiquitous within the environment, food, industrial and physiological systems and is mostly present as hydrated anion of a corresponding dissolved salt. Due to the significant environmental and toxicological effects of nitrate, its determination and monitoring in environmental and industrial waters are often necessary. A wide range of analytical techniques are available for nitrate determination in various sample matrices. This review discusses biosensors available for nitrate determination using the enzyme nitrate reductase (NaR). We conclude that nitrate determination using biosensors is an excellent non-toxic alternative to all other available analytical methods. Over the last fifteen years biosensing technology for nitrate analysis has progressed very well, however, there is a need to expedite the development of nitrate biosensors as a suitable alternative to non-enzymatic techniques through the use of different polymers, nanostructures, mediators and strategies to overcome oxygen interference. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Inhibition Effect of Miconazole Nitrate on the Corrosion of Mild Steel in Hydrochloric Acid Medium

    Directory of Open Access Journals (Sweden)

    J. Ishwara Bhat

    2011-01-01

    Full Text Available The corrosion inhibition of mild steel by miconazole nitrate, an antifungal drug has been investigated using potentiodynamic polarization, electrochemical impedance spectroscopy technique, and weight loss methods. The experimental results suggested miconazole nitrate is a good corrosion inhibitor for mild steel in 1 M hydrochloric acid medium. The inhibition efficiency increased with increase in inhibitor concentration. The thermodynamic parameters were determined and discussed. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the surface of mild steel following Langmuir adsorption isotherm.

  11. Calcium gluconate supplementation is effective to balance calcium homeostasis in patients with gastrectomy.

    Science.gov (United States)

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

    2015-03-01

    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

  12. Fluorescence dynamics in supercooled (acetamide + calcium nitrate) molten mixtures

    Science.gov (United States)

    Gazi, Harun Al Rasid; Guchhait, Biswajit; Daschakraborty, Snehasis; Biswas, Ranjit

    2011-01-01

    Fluorescence dynamics of a polar solute probe in molten (CH3CONH2 + Ca(NO3)2·4.37H2O) mixtures have been measured in order to probe the solute-medium interactions in such complex systems. Steady state and time-resolved measurements bear no signatures of mega-value of the static dielectric constant, strong heterogeneity and extremely slow relaxation times reported in dielectric relaxation experiments for these molten mixtures. Subsequent applications of a semi-molecular theory reveal both the solute-medium dipole-dipole and ion-dipole interactions contribute significantly to the measured Stokes' shifts. Calculated average solvation times in the underdamped and overdamped limits of frictional solvent response agree semi-quantitatively with those from time-resolved measurements.

  13. Get Enough Calcium

    Science.gov (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 ...

  14. Calcium carbonate overdose

    Science.gov (United States)

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

  15. Nitrate storage and dissimilatory nitrate reduction by eukaryotic microbes

    DEFF Research Database (Denmark)

    Kamp, Anja; Høgslund, Signe; Risgaard-Petersen, Nils

    2015-01-01

    The microbial nitrogen cycle is one of the most complex and environmentally important element cycles on Earth and has long been thought to be mediated exclusively by prokaryotic microbes. Rather recently, it was discovered that certain eukaryotic microbes are able to store nitrate intracellularly...... and use it for dissimilatory nitrate reduction in the absence of oxygen. The paradigm shift that this entailed is ecologically significant because the eukaryotes in question comprise global players like diatoms, foraminifers, and fungi. This review article provides an unprecedented overview of nitrate...... storage and dissimilatory nitrate reduction by diverse marine eukaryotes placed into an eco-physiological context. The advantage of intracellular nitrate storage for anaerobic energy conservation in oxygen-depleted habitats is explained and the life style enabled by this metabolic trait is described...

  16. Neuroprotective effect of selective DPP-4 inhibitor in experimental vascular dementia.

    Science.gov (United States)

    Jain, Swati; Sharma, Bhupesh

    2015-12-01

    Vascular risk factors are associated with a higher incidence of dementia. Diabetes mellitus is considered as a main risk factor for Alzheimer's disease and vascular dementia. Both forms of dementia are posing greater risk to the world population and are increasing at a faster rate. In the past we have reported the induction of vascular dementia by experimental diabetes. This study investigates the role of vildagliptin, a dipeptidyl peptidase-4 inhibitor in the pharmacological interdiction of pancreatectomy diabetes induced vascular endothelial dysfunction and subsequent vascular dementia in rats. Attentional set shifting and Morris water-maze test were used for assessment of learning and memory. Vascular endothelial function, blood brain barrier permeability, serum glucose, serum nitrite/nitrate, oxidative stress (viz. aortic superoxide anion, brain thiobarbituric acid reactive species and brain glutathione), brain calcium and inflammation (myeloperoxidase) were also estimated. Pancreatectomy diabetes rats have shown impairment of endothelial function, blood brain barrier permeability, learning and memory along with increase in brain inflammation, oxidative stress and calcium. Administration of vildagliptin has significantly attenuated pancreatectomy induced impairment of learning, memory, endothelial function, blood brain barrier permeability and biochemical parameters. It may be concluded that vildagliptin, a dipeptidyl peptidase-4 inhibitor may be considered as potential pharmacological agents for the management of pancreatectomy induced endothelial dysfunction and subsequent vascular dementia. The selective modulators of dipeptidyl peptidase-4 may further be explored for their possible benefits in vascular dementia. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Kinetics of Leaching Calcium from Dolomite

    Directory of Open Access Journals (Sweden)

    Azizi, A.

    2011-06-01

    Full Text Available Magnesia is obtained from magnesite ore and the production process applied should remove accompanying minerals that reduce its refractoriness. Given that magnesite reservoirs are more exploited and largely exhausted, there is a growing need for production of magnesia on the basis of other magnesium minerals. Dolomite is a promising source of magnesia because it forms large deposits, is easy to exploit, and generally contains a small quantity of impurities.The kinetics of calcium leaching from dolomite by magnesium-nitrate solution has been studied. The research program included the influence of temperature, mass fraction of magnesium nitrate in solution, dolomite particle size and leaching time. Time dependence of calcium leaching is described by relevant kinetic equations. Rate coefficients, their temperature dependence and Arrhenius activation energy have been determined.

  18. Oxalate synthesis in leaves is associated with root uptake of nitrate and its assimilation in spinach (Spinacia oleracea L.) plants.

    Science.gov (United States)

    Liu, Xiao Xia; Zhou, Kai; Hu, Yan; Jin, Rong; Lu, Ling Li; Jin, Chong Wei; Lin, Xian Yong

    2015-08-15

    Excessive accumulation of oxalate in numerous vegetables adversely affects their quality as food. While it is known that nitrate could effectively stimulate oxalate accumulation in many vegetables, little information is available about the mechanism of nitrate-induced oxalate accumulation. In this study, we examined the association of oxalate synthesis with nitrate uptake and assimilation in two genotypes of spinach (Spinacia oleracea L.), Heizhenzhu and Weilv. Increasing nitrate levels resulted in enhanced synthesis of oxalate, as well as increased root uptake of nitrate and leaf activities of nitrate reductase (NR) and glutamine synthetase (GS) for both genotypes. Correlation analysis revealed that oxalate accumulation in spinach leaves was positively related with rate of nitrate uptake by roots, as well as leaf activities of NR and GS. Addition of plasmalemma H(+)-ATPase inhibitor sodium vanadate (Na3VO4) significantly decreased leaf oxalate accumulation in both genotypes. Presence of NR or GS inhibitors led to reduction of leaf oxalate contents, GS/NR activities and decreased nitrate uptake rate. Significantly higher levels of nitrate root uptake, leaf NR and GS activities were observed in the high-oxalate genotype Heizhenzhu than in Weilv. Oxalate synthesis in leaves of spinach is not only positively associated with root uptake of nitrate, but also with its assimilation within the plants. © 2014 Society of Chemical Industry.

  19. Evaluation of nitrate destruction methods

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, P.A. [Oak Ridge National Lab., TN (United States); Kurath, D.E.; Guenther, R. [Pacific Northwest Lab., Richland, WA (United States)

    1993-03-30

    A wide variety of high nitrate-concentration aqueous mixed [radioactive and Resource Conservation and Recovery Act (RCRA) hazardous] wastes are stored at various US Department of Energy (DOE) facilities. These wastes will ultimately be solidified for final disposal, although the waste acceptance criteria for the final waste form is still being determined. Because the nitrates in the wastes will normally increase the volume or reduce the integrity of all of the waste forms under consideration for final disposal, nitrate destruction before solidification of the waste will generally be beneficial. This report describes and evaluates various technologies that could be used to destroy the nitrates in the stored wastes. This work was funded by the Department of Energy`s Office of Technology Development, through the Chemical/Physical Technology Support Group of the Mixed Waste Integrated Program. All the nitrate destruction technologies will require further development work before a facility could be designed and built to treat the majority of the stored wastes. Several of the technologies have particularly attractive features: the nitrate to ammonia and ceramic (NAC) process produces an insoluble waste form with a significant volume reduction, electrochemical reduction destroys nitrates without any chemical addition, and the hydrothermal process can simultaneously treat nitrates and organics in both acidic and alkaline wastes. These three technologies have been tested using lab-scale equipment and surrogate solutions. At their current state of development, it is not possible to predict which process will be the most beneficial for a particular waste stream.

  20. TREATMENT OF AMMONIUM NITRATE SOLUTIONS

    Science.gov (United States)

    Boyer, T.W.; MacHutchin, J.G.; Yaffe, L.

    1958-06-10

    The treatment of waste solutions obtained in the processing of neutron- irradiated uranium containing fission products and ammonium nitrate is described. The object of this process is to provide a method whereby the ammonium nitrate is destroyed and removed from the solution so as to permit subsequent concentration of the solution.. In accordance with the process the residual nitrate solutions are treated with an excess of alkyl acid anhydride, such as acetic anhydride. Preferably, the residual nitrate solution is added to an excess of the acetic anhydride at such a rate that external heat is not required. The result of this operation is that the ammonium nitrate and acetic anhydride react to form N/sub 2/ O and acetic acid.

  1. 4-Methoxybenzamidinium nitrate

    Directory of Open Access Journals (Sweden)

    Simona Irrera

    2012-12-01

    Full Text Available The title salt, C8H11N2O+·NO3−, was synthesized by a reaction between 4-methoxybenzamidine (4-amidinoanisole and nitric acid. The asymmetric unit comprises a non-planar 4-methoxybenzamidinium cation and a nitrate anion. In the cation, the amidinium group has two similar C—N bond lengths [1.302 (3 and 1.313 (3 Å] and its plane forms a dihedral angle of 32.66 (5° with the mean plane of the benzene ring. The nitrate–amidinium ion pair is not planar, as the dihedral angle between the planes defined by the CN2+ and NO3− units is 19.28 (6°. The ionic components are associated in the crystal via N—H...O hydrogen bonds, resulting in a three-dimensional network.

  2. Some History of Nitrates

    Science.gov (United States)

    Barnum, Dennis W.

    2003-12-01

    The history of saltpeter is an interesting combination of chemistry, world trade, technology, politics, and warfare. Originally it was obtained from the dirt floors of stables, sheep pens, pigeon houses, caverns, and even peasants' cottages; any place manure and refuse accumulated in soil under dry conditions. When these sources became inadequate to meet demand it was manufactured on saltpeter plantations, located in dry climates, where piles of dirt, limestone, and manure were allowed to stand for three to five years while soil microbes oxidized the nitrogen to nitrate—an example of early bioengineering. Extensive deposits of sodium nitrate were mined in the Atacama Desert in northern Chile from 1830 until the mid 1920s when the mines were displaced by the Haber Ostwald process.

  3. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

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

    1984-01-01

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

  4. Application of classification-tree methods to identify nitrate sources in ground water.

    Science.gov (United States)

    Spruill, Timothy B; Showers, William J; Howe, Stephen S

    2002-01-01

    A study was conducted to determine if nitrate sources in ground water (fertilizer on crops, fertilizer on golf courses, irrigation spray from hog (Sus scrofa) wastes, and leachate from poultry litter and septic systems) could be classified with 80% or greater success. Two statistical classification-tree models were devised from 48 water samples containing nitrate from five source categories. Model 1 was constructed by evaluating 32 variables and selecting four primary predictor variables (delta 15N, nitrate to ammonia ratio, sodium to potassium ratio, and zinc) to identify nitrate sources. A delta 15N value of nitrate plus potassium > 18.2 indicated animal sources; a value nitrate to ammonia ratio > 575 indicated inorganic fertilizer on agricultural crops; a ratio nitrate from golf courses. A sodium to potassium ratio > 3.2 indicated septic-system wastes; a ratio 2.8 indicated spray wastes from hog lagoons; a value nitrate to ammonia ratio, calcium to magnesium ratio, and sodium to potassium ratio) to distinguish categories. Both models were able to distinguish all five source categories with better than 80% overall success and with 71 to 100% success in individual categories using the learning samples. Seventeen water samples that were not used in model development were tested using Model 2 for three categories, and all were correctly classified. Classification-tree models show great potential in identifying sources of contamination and variables important in the source-identification process.

  5. strawberry to various ratios of ammonium to nitrate nitrogen in nutrient

    African Journals Online (AJOL)

    Jane

    2011-10-03

    Oct 3, 2011 ... Hydroponic production of vegetables and ornamentals. Embryo Publications, Athens, Greece, pp. 179–210. Tabatabaei SJ, Fatemi L, Fallahi E (2006). Effect of ammonium: nitrate ratio on yield, calcium concentration, and photosynthesis rate in strawberry, J. Plant Nutr., 29: 1273–1285. Tabatabei SJ, Yusefi ...

  6. Effects of nitrate addition on phosphorus retention in an eutrophic reservoir : laboratory experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, T.; Janke, H.; Colzato, M.; Beraldo, D.; Mozeto, A. [Univ. Federal de Sao Carlos (Brazil); Botta, C. [Univ. de Sao Paulo (Brazil); Nascimento, M. [Comissao Nacional de Energia Nuclear, Brasilia (Brazil)

    2010-07-01

    The Ibrite reservoir in southeast Brazil is polluted with effluents from an oil refinery as well as domestic untreated sewage from cities in the region. In this study, calcium nitrate was used as a sediment remediation technology in order to reduce phosphorus availability. Experiments were conducted in microcosms incubated for up to 135 days. Ceriodaphnia silvestrii and Vibrio fisheri were used to conduct an acute toxicity assessment of the water column and pore water of the sediments. Chironomus xanthus was used to assess bulk sediments. Results of the chemical analyses showed that high values of acid volatile sulfide in the sediments decreased by 99 per cent after 135 days of incubation. Approximately 50 per cent of the soluble reactive phosphorus was removed from the water column. The toxicity of the tested organisms was attributed to high nitrate concentrations in pore water sediments. Results indicated that calcium nitrate is not suitable as a sediment remediation technology.

  7. Yttrium Nitrate mediated Nitration of Phenols at room temperature in ...

    Indian Academy of Sciences (India)

    Mg(NO3)2,6 VO(NO3)3, Fe(NO3)3, (Me4N)NO3, Ph2. PCl/I2/AgNO3,7 and Zirconyl Nitrate8 were used as the source of nitronium ion. However, these methods need extra reagents such as solid acid or ionic liquids and heating condition. Therefore, finding a green nitration method at ambient temperature is highly desirable.

  8. Nitrate storage and dissimilatory nitrate reduction by eukaryotic microbes

    OpenAIRE

    Anja eKamp; Signe eHøgslund; Nils eRisgaard-Petersen; Peter eStief

    2015-01-01

    The microbial nitrogen cycle is one of the most complex and environmentally important element cycles on Earth and has long been thought to be mediated exclusively by prokaryotic microbes. Rather recently, it was discovered that certain eukaryotic microbes are able to store nitrate intracellularly and use it for dissimilatory nitrate reduction in the absence of oxygen. The paradigm shift that this entailed is ecologically significant because the eukaryotes in question comprise global players l...

  9. Enhanced xanthine oxidoreductase expression and tissue nitrate reduction in germ free mice.

    Science.gov (United States)

    Huang, Liyue; Borniquel, Sara; Lundberg, Jon O

    2010-02-15

    The nitrate-nitrite-NO pathway is emerging as an alternative to the l-arginine/NO-synthase pathway for the generation of NO in mammals. Bioactivation of the stable nitrate anion involves initial reduction to nitrite by commensal bacteria in the gastrointestinal tract. Nitrite is then further metabolized in blood and tissues to form nitric oxide (NO) and other bioactive nitrogen oxides. In addition to nitrate reduction by bacteria, a functional mammalian nitrate reductase activity was recently explored. It was demonstrated that xanthine oxidoreductase (XOR) and possibly other enzymes can catalyze nitrate reduction under normoxic conditions in vivo. In the present study, we compared nitrate reduction in germ free (GF) and conventional mice. One aim was to see if the complete lack of bacterial nitrate reduction in the GF mice would be associated with an upregulation of mammalian nitrate reductase activity. Sodium nitrate (NaNO(3)) or placebo (NaCl) was injected intraperitoneally and blood and tissues were collected 1.5-2h later for measurements of nitrate and nitrite and in some cases analyses of protein expression. Tissue and plasma levels of nitrate increased to a similar extent in conventional and GF animals after nitrate administration. Plasma nitrite was 3-fold higher in GF mice receiving nitrate compared to placebo while this effect of nitrate was absent in the conventional mice. In GF mice pretreated with the xanthine oxidase inhibitor allopurinol the increase in nitrite was attenuated. The levels of nitrite in the liver and small intestine increased after the nitrate load in GF mice but not in the conventional mice. Anaerobic nitrate reduction to nitrite in intestinal tissue homogenates was also accelerated in GF mice. Studies of tissue protein levels revealed increased expression of XOR in the livers of GF animals. We conclude that XOR expression in tissues is enhanced in germ free mice and this may explain the apparently greater tissue nitrate reductase

  10. Coronary Calcium Scan

    Science.gov (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 ...

  11. Nitration Reactions of Ethyl Centralite

    Science.gov (United States)

    1975-05-01

    seront utilisees dans les etudes de stabilite du vieillissement accglgre des poudres ä canon. (NC) ABSTRACT Preliminary experiments are described where...quantity for definite characterization. Detailed examination by thin layer chromato- graphy of residues from nitration experiments, however

  12. Avaliação de doses e épocas de aplicação de nitrato de cálcio em cobertura na cultura do rabanete Evaluation of calcium nitrate level and timing of top-dressing in radish

    Directory of Open Access Journals (Sweden)

    Antonio Ismael Inácio Cardoso

    2001-11-01

    Full Text Available Este experimento foi realizado para avaliar o efeito de doses e épocas de aplicação de nitrogênio em cobertura na cultura do rabanete (cultivar Redondo Vermelho. Foram avaliados sete tratamentos com cinco repetições e parcelas com 1,2 m x 0,8 m (espaçamento de 20 cm x 5 cm, no delineamento experimental em blocos ao acaso. Os tratamentos resultaram da combinação dos fatores época da adubação em cobertura [9 e 20 dias após a semeadura (DAS] e doses de nitrogênio (100; 200 e 300 kg/ha na forma de nitrato de cálcio, além da testemunha, sem adubação em cobertura. Em geral, a época de aplicação foi mais importante que o nível de N em cobertura. Quando a adubação foi realizada 9 DAS obteve-se uma produção de 10,30 t/ha de folhas, 10,6 t/ha de raízes (total e 6,20 t/ha de raízes comerciais, superior à adubação realizada aos 20 DAS (7,7 t/ha, 5,8 t/ha e 2,7 t/ha de folhas, raízes totais e raízes comerciais, respectivamente. Quanto às doses de N, a produção de raízes comerciais foi superior com 300 kg/ha (5,1 t/ha em comparação a 100 kg/ha (3,6 t/ha. Para as condições em que foi realizado este experimento, as maiores produções de raízes comerciais foram obtidas com 200 ou 300 kg/ha de N, aplicados 9 DAS, recomendando-se 200 kg/ha pelo menor gasto com este insumo.This trial was set out to evaluate the effect of levels and timing of top-dressing with calcium nitrate in radish (cv Redondo Vermelho. Seven treatments [resulted of the combination of two factors: timing of top-dressing (9 and 20 days after sowing-DAS and N level (100; 200 and 300 kg/ha, besides a standard without top-dressing] were evaluated in a randomized complete block design, with five replicates and plots with 1.2 m x 0.8 m. In general, timing of top-dressing was more important than N levels. When fertilization was made 9 DAS shoot yield was 10.3 t/ha, total root yield was 10.6 t/ha and commercial root yield was 6.2 t/ha, superior to fertilization

  13. 21 CFR 172.170 - Sodium nitrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate. 172.170 Section 172.170 Food and... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... sablefish, smoked, cured salmon, and smoked, cured shad, so that the level of sodium nitrate does not exceed...

  14. Calcium source (image)

    Science.gov (United States)

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

  15. Calcium and bones (image)

    Science.gov (United States)

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

  16. Calcium hydroxide poisoning

    Science.gov (United States)

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

  17. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

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

  18. Calcium blood test

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003477.htm 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. ...

  19. Nitric oxide-derived urinary nitrate as a marker of intestinal bacterial translocation in rats.

    Science.gov (United States)

    Oudenhoven, I M; Klaasen, H L; Lapré, J A; Weerkamp, A H; Van der Meer, R

    1994-07-01

    Bacterial translocation across the gut wall may lead to bacteremia and sepsis. Bacteriological analyses are laborious and time consuming, which precludes a rapid diagnosis of bacterial translocation. Synthesis of nitric oxide by macrophages is a primary response to bacterial infections. Therefore, the aim of this study was to examine whether NO-derived nitrate excretion in urine can be used as a rapid and quantitative marker of intestinal bacterial translocation. The kinetics of urinary nitrate excretion was determined in rats intraperitoneally injected with increasing doses of Salmonella enteritidis lipopolysaccharide. Subsequently, the response to bacterial translocation was studied in rats infected orally with different doses of viable, invasive S. enteritidis. Increasing the lipopolysaccharide dose from 0.05 to 0.50 mg/kg resulted in a transient, dose-dependent, almost 10-fold increase in urinary nitrate excretion. Administration of the NO synthase inhibitor NG-nitro-L-arginine methyl ester merely inhibited the increase in nitrate excretion after lipopolysaccharide injection. Increasing the infective dose of viable Salmonella resulted in a time- and dose-dependent exponential increase in nitrate output. Translocation was a prerequisite for provoking a nitrate response. Total urinary nitrate excretion after infection and classical infection parameters, such as weight of the mesenteric lymph nodes and population levels of Salmonella in feces, were highly correlated. Urinary nitrate excretion is a quantitative, noninvasive biomarker of intestinal bacterial translocation, which can be used to follow the course of a systemic infection.

  20. Nitrate metabolism in the gromiid microbial universe

    DEFF Research Database (Denmark)

    Høgslund, Signe; Risgaard-Petersen, Nils; Cedhagen, Tomas

    Eukaryotic nitrate respiration supported by intracellular nitrate storages contributes substantially to the nitrogen cycle. Research focus is currently directed towards two phyla: Foraminifera and diatoms, but the widespread Gromia in the Rhizaria may be another key organism. These giant protists...... to the findings of eukaryotic mediated nitrate reduction in some foraminifera and diatoms, nitrate respiration in gromiids seems to be mediated by bacterial endosymbionts. The role of endobionts in nitrate accumulating eukaryotes is of fundamental importance for understanding the evolutionary path...

  1. Sodium nitrate ingestion increases skeletal muscle nitrate content in humans.

    Science.gov (United States)

    Nyakayiru, Jean; Kouw, Imre W K; Cermak, Naomi M; Senden, Joan M; van Loon, Luc J C; Verdijk, Lex B

    2017-09-01

    Nitrate ([Formula: see text]) ingestion has been shown to have vasoactive and ergogenic effects that have been attributed to increased nitric oxide (NO) production. Recent observations in rodents suggest that skeletal muscle tissue serves as an endogenous [Formula: see text] "reservoir." The present study determined [Formula: see text] contents in human skeletal muscle tissue in a postabsorptive state and following ingestion of a sodium nitrate bolus (NaNO 3 ). Seventeen male, type 2 diabetes patients (age 72 ± 1 yr; body mass index 26.5 ± 0.5 kg/m 2 ; means ± SE) were randomized to ingest a dose of NaNO 3 (NIT; 9.3 mg [Formula: see text]/kg body wt) or placebo (PLA; 8.8 mg NaCl/kg body wt). Blood and muscle biopsy samples were taken before and up to 7 h following [Formula: see text] or placebo ingestion to assess [Formula: see text] [and plasma nitrite ([Formula: see text])] concentrations. Additionally, basal plasma and muscle [Formula: see text] concentrations were assessed in 10 healthy young (CON-Y; age 21 ± 1 yr) and 10 healthy older (CON-O; age 75 ± 1 yr) control subjects. In all groups, baseline [Formula: see text] concentrations were higher in muscle (NIT, 57 ± 7; PLA, 61 ± 7; CON-Y, 80 ± 10; CON-O, 54 ± 6 µmol/l) than in plasma (NIT, 35 ± 3; PLA, 32 ± 3; CON-Y, 38 ± 3; CON-O, 33 ± 3 µmol/l; P ≤ 0.011). Ingestion of NaNO 3 resulted in a sustained increase in plasma [Formula: see text], plasma [Formula: see text], and muscle [Formula: see text] concentrations (up to 185 ± 25 µmol/l) in the NIT group (time effect P nitrate ingestion is usually limited to the changes observed in plasma nitrate and nitrite concentrations. The present investigation assessed the skeletal muscle nitrate content in humans during the postabsorptive state, as well as following dietary nitrate ingestion. We show that basal nitrate content is higher in skeletal muscle tissue than in plasma and that ingestion of a dietary nitrate bolus strongly increases both plasma

  2. NITRATE DESTRUCTION LITERATURE SURVEY AND EVALUATION CRITERIA

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J.

    2011-02-01

    This report satisfies the initial phase of Task WP-2.3.4 Alternative Sodium Recovery Technology, Subtask 1; Develop Near-Tank Nitrate/Nitrite Destruction Technology. Some of the more common anions in carbon steel waste tanks at SRS and Hanford Site are nitrate which is corrosive, and nitrite and hydroxide which are corrosion inhibitors. At present it is necessary to periodically add large quantities of 50 wt% caustic to waste tanks. There are three primary reasons for this addition. First, when the contents of salt tanks are dissolved, sodium hydroxide preferentially dissolves and is removed. During the dissolution process the concentration of free hydroxide in the tank liquid can decrease from 9 M to less than 0.2 M. As a result, roughly half way through the dissolution process large quantities of sodium hydroxide must be added to the tank to comply with requirements for corrosion control. Second, hydroxide is continuously consumed by reaction with carbon dioxide which occurs naturally in purge air used to prevent buildup of hydrogen gas inside the tanks. The hydrogen is generated by radiolysis of water. Third, increasing the concentration of hydroxide increases solubility of some aluminum compounds, which is desirable in processing waste. A process that converts nitrate and nitrite to hydroxide would reduce certain costs. (1) Less caustic would be purchased. (2) Some of the aluminum solid compounds in the waste tanks would become more soluble so less mass of solids would be sent to High Level Vitrification and therefore it would be not be necessary to make as much expensive high level vitrified product. (3) Less mass of sodium would be fed to Saltstone at SRS or Low Level Vitrification at Hanford Site so it would not be necessary to make as much low level product. (4) At SRS less nitrite and nitrate would be sent to Defense Waste Processing Facility (DWPF) so less formic acid would be consumed there and less hydrogen gas would be generated. This task involves

  3. Gualou Guizhi decoction reverses brain damage with cerebral ischemic stroke, multi-component directed multi-target to screen calcium-overload inhibitors using combination of molecular docking and protein-protein docking.

    Science.gov (United States)

    Hu, Juan; Pang, Wen-Sheng; Han, Jing; Zhang, Kuan; Zhang, Ji-Zhou; Chen, Li-Dian

    2018-12-01

    Stroke is a disease of the leading causes of mortality and disability across the world, but the benefits of drugs curative effects look less compelling, intracellular calcium overload is considered to be a key pathologic factor for ischemic stroke. Gualou Guizhi decoction (GLGZD), a classical Chinese medicine compound prescription, it has been used to human clinical therapy of sequela of cerebral ischemia stroke for 10 years. This work investigated the GLGZD improved prescription against intracellular calcium overload could decreased the concentration of [Ca2+]i in cortex and striatum neurone of MCAO rats. GLGZD contains Trichosanthin and various small molecular that they are the potential active ingredients directed against NR2A, NR2B, FKBP12 and Calnodulin target proteins/enzyme have been screened by computer simulation. "Multicomponent systems" is capable to create pharmacological superposition effects. The Chinese medicine compound prescriptions could be considered as promising sources of candidates for discovery new agents.

  4. Nitrate reduction functional genes and nitrate reduction potentials persist in deeper estuarine sediments. Why?

    National Research Council Canada - National Science Library

    Papaspyrou, Sokratis; Smith, Cindy J; Dong, Liang F; Whitby, Corinne; Dumbrell, Alex J; Nedwell, David B

    2014-01-01

    Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon...

  5. The putative P-gp inhibitor telmisartan does not affect the transcellular permeability and cellular uptake of the calcium channel antagonist verapamil in the P-glycoprotein expressing cell line MDCK II MDR1

    DEFF Research Database (Denmark)

    Saaby, Lasse; Tfelt-Hansen, Peer; Brodin, Birger

    2015-01-01

    of verapamil. Fluxes of radiolabelled verapamil across MDCK II MDR1 monolayers were measured in the absence and presence of the putative P-gp inhibitor telmisartan (a clinically approved drug compound). Verapamil displayed a vectorial basolateral-to-apical transepithelial efflux across the MDCK II MDR1...

  6. The relationship between the nitrogen and nitrate content and nitrate ...

    African Journals Online (AJOL)

    The interrelationships between the nitrate-N and nitrogen content and dry matter yield of Midmar ryegrass (Lolium multiflorum cv. Midmar) were investigated. Data were collected from N fertility trials, from two seasons (1985 and 1987) on four soil sites (Metz, Griffin, Clovelly and Katspruit) with N fertilizer rates ranging from 0 ...

  7. The effect of nitrate on ethylene biofiltration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Hun, E-mail: lee323@alumni.purdue.edu [Department of Agricultural and Biological Engineering, Purdue University, 225 South University St., West Lafayette, 47907-2093 IN (United States); Li, Congna; Heber, Albert J. [Department of Agricultural and Biological Engineering, Purdue University, 225 South University St., West Lafayette, 47907-2093 IN (United States)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Ethylene biofiltration strongly depends on nitrate concentrations and media types. Black-Right-Pointing-Pointer We examine reduced N supply can increase ethylene removals in biofilters. Black-Right-Pointing-Pointer Perlite medium is better for ethylene biofiltration than activated carbon medium. - Abstract: This study investigated the effects of filter media types and nitrate (NO{sub 3}{sup -}) concentrations in nutrient solutions on C{sub 2}H{sub 4} biofiltration. A new nutrient solution with zero NO{sub 3}{sup -} concentration was supplied to two perlite-bed biotrickling filters, two perlite-bed biofilters, and two GAC (Granular Activated Carbon)-bed biofilters, while the other with 2 g L{sup -1} of NO{sub 3}{sup -} was used for the other two GAC biofilters. All reactors underwent a total test duration of over 175 days with an EBRT (Empty Bed Residence Time) of 30 s, inlet gas flow rate of 7 L min{sup -1}, and inlet C{sub 2}H{sub 4} concentrations of 20-30 mg m{sup -3}. NO{sub 3}{sup -} concentration and media type significantly affected the C{sub 2}H{sub 4} removal efficiencies in all types of biofiltration. The perlite media with no NO{sub 3}{sup -} achieved C{sub 2}H{sub 4} removal efficiencies 10-50% higher than the others. A NO{sub 3}{sup -} concentration as high as 2 g L{sup -1} in the original nutrient solution may act as an inhibitor that suppresses the growth or activity of C{sub 2}H{sub 4} degraders. In addition, the perlite media resulted in higher C{sub 2}H{sub 4} removal efficiencies than GAC media, because the hydrophilic surface of the perlite leads to a higher moisture content and thus to favorable microbial growth.

  8. Workgroup Report: Drinking-Water Nitrate and Health—Recent Findings and Research Needs

    Science.gov (United States)

    Ward, Mary H.; deKok, Theo M.; Levallois, Patrick; Brender, Jean; Gulis, Gabriel; Nolan, Bernard T.; VanDerslice, James

    2005-01-01

    Human alteration of the nitrogen cycle has resulted in steadily accumulating nitrate in our water resources. The U.S. maximum contaminant level and World Health Organization guidelines for nitrate in drinking water were promulgated to protect infants from developing methemoglobinemia, an acute condition. Some scientists have recently suggested that the regulatory limit for nitrate is overly conservative; however, they have not thoroughly considered chronic health outcomes. In August 2004, a symposium on drinking-water nitrate and health was held at the International Society for Environmental Epidemiology meeting to evaluate nitrate exposures and associated health effects in relation to the current regulatory limit. The contribution of drinking-water nitrate toward endogenous formation of N-nitroso compounds was evaluated with a focus toward identifying subpopulations with increased rates of nitrosation. Adverse health effects may be the result of a complex interaction of the amount of nitrate ingested, the concomitant ingestion of nitrosation cofactors and precursors, and specific medical conditions that increase nitrosation. Workshop participants concluded that more experimental studies are needed and that a particularly fruitful approach may be to conduct epidemiologic studies among susceptible subgroups with increased endogenous nitrosation. The few epidemiologic studies that have evaluated intake of nitrosation precursors and/or nitrosation inhibitors have observed elevated risks for colon cancer and neural tube defects associated with drinking-water nitrate concentrations below the regulatory limit. The role of drinking-water nitrate exposure as a risk factor for specific cancers, reproductive outcomes, and other chronic health effects must be studied more thoroughly before changes to the regulatory level for nitrate in drinking water can be considered. PMID:16263519

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

    OpenAIRE

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

    1981-01-01

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

  10. [Effect of lignosulfonates on controlling of urea nitrogen transformation and nitrate accumulation in vegetable].

    Science.gov (United States)

    Wang, Dehan; Peng, Junjie; Lin, Huidong; Liao, Zongwen

    2003-09-01

    Indoor cultivation experiment and plot field experiment were conducted to study the effect of lignosulfonates on urea nitrogen transformation in soil and the mechanism of controlling nitrate pollution in vegetable. Results showed that lignosulfonates behaved inhibition effect on urea hydrolysis compared with the contrast treatment, the contents of remainder urea nitrogen treated with lignosulfonates was more than that of another kind of urease inhibitor hydroquinone in soil after 69 hours' cultivation. Lignosulfonates could reduce contents of nitrate in cabbage, it as well increase contents of vitamin C in a large degree, enhance the nitrate reductase activity, then accelerated nitrogen assimilation in plants. The urease activity was lower and contents of ammonium nitrogen in soil was larger after ingathering, lignosulfonates could keep nitrogen release slowly, and could be used as a kind of effective inhibitor to nitrogen fertilizer in the controlled-release fertilizers.

  11. Influência da aplicação de gesso na produção de matéria seca, na relação nitrogênio: enxofre e concentrações de enxofre, cobre, nitrogênio e nitrato em pastagens de Brachiaria decumbens Stapf Influence of calcium sulphate fertilization on dry matter yield, nitrogen/sulfur relation and sulphur, copper, nitrogen and nitrate concentrations in Brachiaria decumbens Stapf

    Directory of Open Access Journals (Sweden)

    L.M. Guedes

    2000-10-01

    Full Text Available Em solo classificado como latossolo vermelho-amarelo, de pH igual a 5,2, foram estudados o efeito da adição crescente do gesso agrícola (CaSO4.2H2O nos níveis de 0 t/ha (T; 0,5 t/ha (TA; 1,0 t/ha (TB e 1,5 t/ha (TC, combinados com a aplicação de 20kg/ha de nitrogênio sob a forma de uréia mais 80kg de K2O/ha sob a forma de cloreto de potássio, sobre a produção de matéria seca (MS da Brachiaria decumbens Stapf, no período de janeiro a dezembro. O delineamento experimental foi o de blocos ao acaso, com quatro repetições. Foram realizados três cortes (após 77, 133 e 341 dias do início do experimento para determinar a produção de matéria seca/ha e as concentrações de enxofre (S, nitrogênio (N, cobre (Cu e nitrato na forrageira. Observou-se que a produção de MS foi influenciada pelos tratamentos e época de corte da forrageira. Porém, não houve aumento significativo na produção de MS para níveis de adubação acima de 0,5 t/ha. As concentrações de S, N, Cu e nitrato não foram influenciadas pelos tratamentos.The study was conducted in a Brachiaria decumbens pasture, in a dark red-yellow latosol, pH 5.2, with the objective of evaluating the influence of crescent levels of calcium sulphate application and cutting-age on dry matter yield and on N, S, Cu and nitrate content. Four treatments and three cuts were done as follow: T (control, 0 ton/ha of calcium sulphate; TA, 0.5 ton/ha; TB, 1.0 ton/ha; and TC, 1.5 ton/ha. The cuts were done 77, 133 and 341 days after the beginning of the experiment. The experiment was set in a randomized complete block design, with four replications. The dry matter yield of TA, TB and TC showed differences (P0.05 between TA, TB and TC. Concentrations of S, Cu, N and nitrate in dry matter did not show differences (P>0.05 between treatments. However, the grass cutting-age influenced grass mineral concentrations (P<0.05 in all treatments.

  12. Effects of melatonin on seedling growth, mineral nutrition, and nitrogen metabolism in cucumber under nitrate stress.

    Science.gov (United States)

    Zhang, Ruimin; Sun, Yunkuo; Liu, Zeyu; Jin, Wen; Sun, Yan

    2017-05-01

    In China, excessive use of nitrogen fertilizers in glasshouses leads to nitrate accumulations in soil and plants, which then limits productivity. Melatonin, an evolutionarily highly conserved molecule, has a wide range of functions in plants. We analyzed the effects of melatonin pretreatment on the growth, mineral nutrition, and nitrogen metabolism in cucumber (Cucumis sativus L. "Jin You No. 1") when seedlings were exposed to nitrate stress. An application of 0.1 mmol/L melatonin significantly improved the growth of plants and reduced their susceptibility to damage due to high nitrate levels (0.6 mol/L) during the ensuing period of stress treatment. Although excess nitrate led to an increase in the concentrations of nitrogen, potassium, and calcium, as well as a decrease in levels of phosphorus and magnesium, exogenous melatonin generally had the opposite effect except for a further rise in calcium concentrations. Pretreatment also significantly reduced the accumulations of nitrate nitrogen and ammonium nitrogen and enhanced the activities of enzymes involved in nitrogen metabolism. Expression of Cs-NR and Cs-GOGAT, two genes that function in that metabolism, was greatly down-regulated when plants were exposed to 0.6 mol/L nitrate, but was up-regulated in plants that had received the 0.1 mmol/L melatonin pretreatment. Our results are the first evidence that melatonin has an important role in modulating the composition of mineral elements and nitrogen metabolism, thereby alleviating the inhibitory effect on growth normally associated with nitrate stress. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Efficiency of nitrate uptake in spinach : impact of external nitrate concentration and relative growth rate on nitrate influx and efflux

    NARCIS (Netherlands)

    Ter Steege, MW; Stulen, [No Value; Wiersema, PK; Posthumus, F; Vaalburg, W

    1999-01-01

    Regulation of nitrate influx and efflux in spinach (Spinacia oleracea L., cv. Subito), was studied in short-term label experiments with N-13- and N-15-nitrate. Nitrate fluxes were examined in relation to the N demand for growth, defined as relative growth rate (RGR) times plant N concentration.

  14. 2,5-Dimethylanilinium nitrate

    Directory of Open Access Journals (Sweden)

    Wajda Smirani

    2009-08-01

    Full Text Available In the title salt, C8H12N+·NO3−, all non-H atoms of the cation lie on mirror planes. The nitrate counteranion has m symmetry and acts as a hydrogen-bond acceptor of N—H...O hydrogen bonds, connecting the cations and anions into layers running parallel to the ab plane.

  15. Nitrate Removal from Ground Water: A Review

    OpenAIRE

    Archna; Surinder K. Sharma; Ranbir Chander Sobti

    2012-01-01

    Nitrate contamination of ground water resources has increased in Asia, Europe, United States, and various other parts of the world. This trend has raised concern as nitrates cause methemoglobinemia and cancer. Several treatment processes can remove nitrates from water with varying degrees of efficiency, cost, and ease of operation. Available technical data, experience, and economics indicate that biological denitrification is more acceptable for nitrate removal than reverse osmosis and ion ex...

  16. Plasma nitrate and nitrite are increased by a high nitrate supplement, but not by high nitrate foods in older adults

    Science.gov (United States)

    Miller, Gary D.; Marsh, Anthony P.; Dove, Robin W.; Beavers, Daniel; Presley, Tennille; Helms, Christine; Bechtold, Erika; King, S. Bruce; Kim-Shapiro, Daniel

    2012-01-01

    Little is known about the effect of dietary nitrate on the nitrate/nitrite/NO (nitric oxide) cycle in older adults. We examined the effect of a 3-day control diet vs. high nitrate diet, with and without a high nitrate supplement (beetroot juice), on plasma nitrate and nitrite kinetics, and blood pressure using a randomized four period cross-over controlled design. We hypothesized that the high nitrate diet would show higher levels of plasma nitrate/nitrite and blood pressure compared to the control diet, which would be potentiated by the supplement. Participants were eight normotensive older men and women (5 female, 3 male, 72.5±4.7 yrs) with no overt disease or medications that affect NO metabolism. Plasma nitrate and nitrite levels and blood pressure were measured prior to and hourly for 3 hours after each meal. The mean daily changes in plasma nitrate and nitrite were significantly different from baseline for both control diet+supplement (p<0.001 and =0.017 for nitrate and nitrite, respectively) and high nitrate diet+supplement (p=0.001 and 0.002), but not for control diet (p=0.713 and 0.741) or high nitrate diet (p=0.852 and 0.500). Blood pressure decreased from the morning baseline measure to the three 2 hr post-meal follow-up time-points for all treatments, but there was no main effect for treatment. In healthy older adults, a high nitrate supplement consumed at breakfast elevated plasma nitrate and nitrite levels throughout the day. This observation may have practical utility for the timing of intake of a nitrate supplement with physical activity for older adults with vascular dysfunction. PMID:22464802

  17. Nitrate reductase assay using sodium nitrate for rapid detection of multidrug resistant tuberculosis

    Science.gov (United States)

    Macedo, Maíra Bidart; Groll, Andrea Von; Fissette, Krista; Palomino, Juan Carlos; da Silva, Pedro Eduardo Almeida; Martin, Anandi

    2012-01-01

    We validated the nitrate reductase assay (NRA) for the detection of multidrug-resistant Mycobacterium tuberculosis (MDR-TB) using sodium nitrate (NaNO3) in replacement of potassium nitrate (KNO3) as nitrate source. NaNO3 is cheaper than KNO3 and has no restriction on use which facilitates the implementation of NRA to detect MDR-TB. PMID:24031916

  18. Nitrate reductase assay using sodium nitrate for rapid detection of multidrug resistant tuberculosis

    OpenAIRE

    Macedo, Ma?ra Bidart; Groll, Andrea Von; Fissette, Krista; Palomino, Juan Carlos; da Silva, Pedro Eduardo Almeida; Martin, Anandi

    2012-01-01

    We validated the nitrate reductase assay (NRA) for the detection of multidrug-resistant Mycobacterium tuberculosis (MDR-TB) using sodium nitrate (NaNO3) in replacement of potassium nitrate (KNO3) as nitrate source. NaNO3 is cheaper than KNO3 and has no restriction on use which facilitates the implementation of NRA to detect MDR-TB.

  19. Nitrate tolerance impairs nitric oxide-mediated vasodilation in vivo

    DEFF Research Database (Denmark)

    Laursen, Jørn Bech; Boesgaard, Søren; Poulsen, Henrik E.

    1996-01-01

    Nitrates, Nitrate tolerence, Nitric oxide, acetylcholine, N-acetylcholine, N-acetylcysteine, L-NAME, Rat, Anesthetized......Nitrates, Nitrate tolerence, Nitric oxide, acetylcholine, N-acetylcholine, N-acetylcysteine, L-NAME, Rat, Anesthetized...

  20. 76 FR 47238 - Ammonium Nitrate From Russia

    Science.gov (United States)

    2011-08-04

    ... COMMISSION Ammonium Nitrate From Russia Determination On the basis of the record \\1\\ developed in the subject... order on ammonium nitrate from Russia would be likely to lead to continuation or recurrence of material... Commission are contained in USITC Publication 4249 (August 2011), entitled Ammonium Nitrate from Russia...

  1. 76 FR 11273 - Ammonium Nitrate From Russia

    Science.gov (United States)

    2011-03-01

    ... COMMISSION Ammonium Nitrate From Russia AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the suspended investigation on ammonium nitrate from Russia... investigation on ammonium nitrate from Russia would be likely to lead to continuation or recurrence of material...

  2. XPS and GDOES Characterization of Porous Coating Enriched with Copper and Calcium Obtained on Tantalum via Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Krzysztof Rokosz

    2016-01-01

    Full Text Available XPS and GDOES characterizations of porous coatings on tantalum after Plasma Electrolytic Oxidation (PEO at 450 V for 3 minutes in electrolyte containing concentrated (85% phosphoric acid with calcium nitrate and copper (II nitrate are described. Based on the obtained data, it may be concluded that the PEO coating consists of tantalum (Ta5+, calcium (Ca2+, copper (Cu2+  and Cu+, and phosphates (PO43-. It has to be pointed out that copper and calcium are distributed throughout the volume. The authors also propose a new model of PEO, based on the derivative of GDOES signals with sputtering time.

  3. Substitutions in Calcium Aluminates and Calcium Aluminoferrites.

    Science.gov (United States)

    ALUMINUM COMPOUNDS, *CEMENTS, * CALCIUM COMPOUNDS, * FERRITES , *SCIENTIFIC RESEARCH, INFRARED SPECTROSCOPY, X RAY DIFFRACTION, CHEMICAL COMPOSITION, SUBSTITUTES, CHEMICAL ANALYSIS, ALKALI METAL COMPOUNDS.

  4. Nitrate Deposition to Surface Snow at Summit, Greenland, Following the 9 November 2000 Solar Proton Event

    Science.gov (United States)

    Duderstadt, Katharine A.; Dibb, Jack E.; Schwadron, Nathan A.; Spence, Harlan E.; Jackman, Charles Herbert; Randall, Cora E.; Solomon, Stanley C.; Mills, Michael J.

    2014-01-01

    This study considers whether spurious peaks in nitrate ions in snow sampled at Summit, Greenland from August 2000 to August 2002 are related to solar proton events. After identifying tropospheric sources of nitrate on the basis of correlations with sulfate, ammonium, sodium, and calcium, we use the three-dimensional global Whole Atmosphere Community Climate Model (WACCM) to examine unaccounted for nitrate spikes. Model calculations confirm that solar proton events significantly impact HOx, NOx, and O3 levels in the mesosphere and stratosphere during the weeks and months following the major 9 November 2000 solar proton event. However, SPE-enhanced NOy calculated within the atmospheric column is too small to account for the observed nitrate ion peaks in surface snow. Instead, our WACCM results suggest that nitrate spikes not readily accounted for by measurement correlations are likely of anthropogenic origin. These results, consistent with other recent studies, imply that nitrate spikes in ice cores are not suitable proxies for individual SPEs and motivate the need to identify alternative proxies.

  5. Analytical Chemistry and Materials Characterization Results for Debris Recovered from Nitrate Salt Waste Drum S855793

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Patrick Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chamberlin, Rebecca M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schwartz, Daniel S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Worley, Christopher Gordon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Garduno, Katherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lujan, Elmer J. W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Borrego, Andres Patricio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Castro, Alonso [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Colletti, Lisa Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fulwyler, James Brent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Holland, Charlotte S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Keller, Russell C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Klundt, Dylan James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martin, Frances Louise [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Montoya, Dennis Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Myers, Steven Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Porterfield, Donivan R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schake, Ann Rene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schappert, Michael Francis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Soderberg, Constance B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Spencer, Khalil J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stanley, Floyd E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Thomas, Mariam R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Townsend, Lisa Ellen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Xu, Ning [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-16

    Solid debris was recovered from the previously-emptied nitrate salt waste drum S855793. The bulk sample was nondestructively assayed for radionuclides in its as-received condition. Three monoliths were selected for further characterization. Two of the monoliths, designated Specimen 1 and 3, consisted primarily of sodium nitrate and lead nitrate, with smaller amounts of lead nitrate oxalate and lead oxide by powder x-ray diffraction. The third monolith, Specimen 2, had a complex composition; lead carbonate was identified as the predominant component, and smaller amounts of nitrate, nitrite and carbonate salts of lead, magnesium and sodium were also identified. Microfocused x-ray fluorescence (MXRF) mapping showed that lead was ubiquitous throughout the cross-sections of Specimens 1 and 2, while heteroelements such as potassium, calcium, chromium, iron, and nickel were found in localized deposits. MXRF examination and destructive analysis of fragments of Specimen 3 showed elevated concentrations of iron, which were broadly distributed through the sample. With the exception of its high iron content and low carbon content, the chemical composition of Specimen 3 was within the ranges of values previously observed in four other nitrate salt samples recovered from emptied waste drums.

  6. Nitrate Removal from Ground Water: A Review

    Directory of Open Access Journals (Sweden)

    Archna

    2012-01-01

    Full Text Available Nitrate contamination of ground water resources has increased in Asia, Europe, United States, and various other parts of the world. This trend has raised concern as nitrates cause methemoglobinemia and cancer. Several treatment processes can remove nitrates from water with varying degrees of efficiency, cost, and ease of operation. Available technical data, experience, and economics indicate that biological denitrification is more acceptable for nitrate removal than reverse osmosis and ion exchange. This paper reviews the developments in the field of nitrate removal processes which can be effectively used for denitrifying ground water as well as industrial water.

  7. Calcium channel blocker overdose

    Science.gov (United States)

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

  8. Fenoprofen calcium overdose

    Science.gov (United States)

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

  9. Dietary nitrate supplementation and exercise performance.

    Science.gov (United States)

    Jones, Andrew M

    2014-05-01

    Dietary nitrate is growing in popularity as a sports nutrition supplement. This article reviews the evidence base for the potential of inorganic nitrate to enhance sports and exercise performance. Inorganic nitrate is present in numerous foodstuffs and is abundant in green leafy vegetables and beetroot. Following ingestion, nitrate is converted in the body to nitrite and stored and circulated in the blood. In conditions of low oxygen availability, nitrite can be converted into nitric oxide, which is known to play a number of important roles in vascular and metabolic control. Dietary nitrate supplementation increases plasma nitrite concentration and reduces resting blood pressure. Intriguingly, nitrate supplementation also reduces the oxygen cost of submaximal exercise and can, in some circumstances, enhance exercise tolerance and performance. The mechanisms that may be responsible for these effects are reviewed and practical guidelines for safe and efficacious dietary nitrate supplementation are provided.

  10. Oxypurines, protein, glucose and the functional state of blood vasculature are markers of renal calcium stone-forming processes? Observations in men with idiopathic recurrent calcium urolithiasis.

    Science.gov (United States)

    Manoharan, Mahimaidos; Schwille, Paul O

    2002-03-01

    In idiopathic calcium urolithiasis the relationships between oxypurines, accompanying proteins and glucose in urine and plasma, and the associated metabolic activity (MA) are unknown. To establish whether MA is related to these parameters and to calcium oxalate crystallization, or whether it reflects a reaction of metabolism to systemic insults was the major goal of the work. One hundred fifty one males were studied in three trials: trial 1 (n=130 patients) and trial 2 (n=24 patients) were cross-sectional; trial 3 included 11 patients and 14 controls). Mean age was 46 years (trials 1 and 2) and 29 years (trial 3). In trial 1 the stratification was based on the median urinary oxypurine excretion, in trial 2 on the median plasma oxypurine concentration (below or above: Low and High subgroups). No dietary restrictions were imposed, but standardized ambulatory laboratory testing was carried out. MA was quantitated by a score. Established analytical methods were used, except for oxypurine measurement which was done by high performance liquid chromatography. Patients with kidney stones tended to be overweight (body mass index >25 kg/(m)2) and to have fasting hyperglycemia. In trial 1 severe oxypurinuria, and especially severe xanthinuria, was associated with an increase in urinary pH, creatinine clearance, proteins, uric acid, malonedialdehyde (indicator of lipid peroxidation), systolic blood pressure, and with a decrease in plasma uric acid (synonymous with a decrease of antioxidant capacity). Tubular reabsorption of proteins and stone-forming substances was diminished but MA remained unchanged despite slightly increased calcium oxalate crystal growth. In trial 2 high adenosine and xanthine coincided with elevated systolic and diastolic blood pressure, high uric acid with high urinary malonedialdehyde, high summed oxypurines minus uric acid with an increase of diastolic blood pressure, glycemia and MA; urinary nitrate (indicator of systemic vasodilation) was unchanged

  11. 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

    2007-08-11

    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.

  12. 5-Chloro-8-hydroxyquinolinium nitrate

    Directory of Open Access Journals (Sweden)

    Seik Weng Ng

    2009-06-01

    Full Text Available The 5-chloro-8-hydroxyquinolinium cation in the the title ion pair, C9H7ClNO+·NO3−, is approximately coplanar with the nitrate anion [dihedral angle = 16.1 (1°]. Two ion pairs are hydrogen bonded (2 × O—H...O and 2 × N—H...O about a center of inversion, generating an R44(14 ring.

  13. 2-Amino-5-chloropyridinium nitrate

    Directory of Open Access Journals (Sweden)

    Donia Zaouali Zgolli

    2009-11-01

    Full Text Available The title structure, C5H6ClN2+·NO3−, is held together by extensive hydrogen bonding between the NO3− ions and 2-amino-5-chloropyridinium H atoms. The cation–anion N—H...O hydrogen bonds link the ions into a zigzag- chain which develops parallel to the b axis. The structure may be compared with that of the related 2-amino-5-cyanopyridinium nitrate.

  14. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

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

  15. Effect of biocides and anionic homopolymeric inhibitors on the ...

    African Journals Online (AJOL)

    This paper describes the effect of biocides and of the anionic homopolymeric inhibitors on the precipitation behavior of calcium fluoride (CaF2).The efficiency of inhibitors in the presence and absence of biocides was calculated using the half-life (t1/2) approach, where 50% of the concentration has been precipitated.

  16. Trifluoroacetic anhydride-catalyzed nitration of toluene as an approach to the specific analysis of nitrate by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Smythe, G A; Matanovic, G; Yi, D; Duncan, M W

    1999-01-01

    The nitration of aromatic compounds by electrophilic substitution is often utilized in analyses of nitrate concentrations in physiological samples by gas chromatographic methods. Problems associated with the use of concentrated sulfuric acid, which is normally used to catalyze this reaction, led us to investigate an alternative method. We describe here a facile GC/MS assay for nitrate in plasma or urine samples which takes advantage of the ability of trifluoroacetic anhydride (TFAA) to catalyze the nitration of aromatics. Toluene, utilized as both reaction solvent and electrophile, was shown to react with nitrate in the presence of TFAA to quantitatively produce the three nitrotoluene isomers (ratio o-:m:p-, approx 57:3:40). Following the incorporation of 15N-labeled nitrate as internal standard, nitrotoluene was quantified using GC/MS by analysis of the selected the ion pairs m/z 120 and 121 (M+ -OH) for the o-isomer or m/z 137 and 138 (molecular ion, M+) for the p-isomer. The limit of detection for nitrate after TFAA-catalyzed conversion to nitrotoluene was less than 100 fmol on column (s/n; 40:1). The TFAA-based GC/MS assay was compared with that utilizing the usual catalyst, concentrated sulfuric acid. With the exception of samples containing nitroarginine analogues, good correlation was found for urine or plasma samples analyzed using either a standard sulfuric acid-catalyzed method or the TFAA-catalyzed procedure. Nitroarginine analogues, which can be present in samples following their use as nitric oxide synthase inhibitors, did not decompose under the conditions of the TFAA-catalyzed assay and, hence, do not give rise to significant interference with nitrate analysis in this procedure. In contrast, catalytic sulfuric acid caused nitroarginine analogues to decompose (essentially quantitatively) and cause spuriously high nitrate levels in samples. The use of TFAA as a catalyst for the nitration of toluene enables a facile and sensitive GC/MS analysis for

  17. Calcium en cardioplegie

    NARCIS (Netherlands)

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

    1985-01-01

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

  18. Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth

    Directory of Open Access Journals (Sweden)

    F. Paulot

    2016-02-01

    Full Text Available We update and evaluate the treatment of nitrate aerosols in the Geophysical Fluid Dynamics Laboratory (GFDL atmospheric model (AM3. Accounting for the radiative effects of nitrate aerosols generally improves the simulated aerosol optical depth, although nitrate concentrations at the surface are biased high. This bias can be reduced by increasing the deposition of nitrate to account for the near-surface volatilization of ammonium nitrate or by neglecting the heterogeneous production of nitric acid to account for the inhibition of N2O5 reactive uptake at high nitrate concentrations. Globally, uncertainties in these processes can impact the simulated nitrate optical depth by up to 25 %, much more than the impact of uncertainties in the seasonality of ammonia emissions (6 % or in the uptake of nitric acid on dust (13 %. Our best estimate for fine nitrate optical depth at 550 nm in 2010 is 0.006 (0.005–0.008. In wintertime, nitrate aerosols are simulated to account for over 30 % of the aerosol optical depth over western Europe and North America. Simulated nitrate optical depth increases by less than 30 % (0.0061–0.010 in response to projected changes in anthropogenic emissions from 2010 to 2050 (e.g., −40 % for SO2 and +38 % for ammonia. This increase is primarily driven by greater concentrations of nitrate in the free troposphere, while surface nitrate concentrations decrease in the midlatitudes following lower concentrations of nitric acid. With the projected increase of ammonia emissions, we show that better constraints on the vertical distribution of ammonia (e.g., convective transport and biomass burning injection and on the sources and sinks of nitric acid (e.g., heterogeneous reaction on dust are needed to improve estimates of future nitrate optical depth.

  19. Nitrate salts suppress sporulation and production of enterotoxin in Clostridium perfringens strain NCTC8239.

    Science.gov (United States)

    Yasugi, Mayo; Otsuka, Keisuke; Miyake, Masami

    2016-10-01

    Clostridium perfringens type A is a common source of food-borne illness in humans. Ingested vegetative cells sporulate in the small intestinal tract and in the process produce C. perfringens enterotoxin (CPE). Although sporulation plays a critical role in the pathogenesis of food-borne illness, the molecules triggering/inhibiting sporulation are still largely unknown. It has previously been reported by our group that sporulation is induced in C. perfringens strain NCTC8239 co-cultured with Caco-2 cells in Dulbecco's Modified Eagle Medium (DMEM). In contrast, an equivalent amount of spores was not observed when bacteria were co-cultured in Roswell Park Memorial Institute-1640 medium (RPMI). In the present study it was found that, when these two media are mixed, RPMI inhibits sporulation and CPE production induced in DMEM. When a component of RPMI was added to DMEM, it was found that calcium nitrate (Ca[NO 3 ] 2 ) significantly inhibits sporulation and CPE production. The number of spores increased when Ca(NO 3 ) 2 -deficient RPMI was used. The other nitrate salts significantly suppressed sporulation, whereas the calcium salts used did not. qPCR revealed that nitrate salts increased expression of bacterial nitrate/nitrite reductase. Furthermore, it was found that nitrite and nitric oxide suppress sporulation. In the sporulation stages, Ca(NO 3 ) 2 down-regulated the genes controlled by Spo0A, a master regulator of sporulation, but not spo0A itself. Collectively, these results indicate that nitrate salts suppress sporulation and CPE production by down-regulating Spo0A-regulated genes in C. perfringens strain NCTC8239. Nitrate reduction may be associated with inhibition of sporulation. © 2016 The Societies and John Wiley & Sons Australia, Ltd.

  20. Calcium antagonists and the diabetic hypertensive patient

    DEFF Research Database (Denmark)

    Parving, H H; Rossing, P

    1993-01-01

    reduces albuminuria, delays the progression of nephropathy, and postpones renal insufficiency in diabetic nephropathy. Calcium antagonists and angiotensin converting enzyme inhibitors induce an acute increase in the glomerular filtration rate, renal plasma flow, and renal sodium excretion...... nephropathy alone and is rapidly rising. Increased arterial blood pressure is an early and common finding in incipient and overt diabetic nephropathy. Fluid and sodium retention with normal concentrations of active renin, angiotensin I and II, and aldosterone has been demonstrated in diabetic renal disease...

  1. Reduction of nitrates in Cucumis sativus L. seedlings II. Influence of tungsten and vanadium on nitrate reductase and adenosine triphosphatase activities

    Directory of Open Access Journals (Sweden)

    Józef Buczek

    2014-01-01

    Full Text Available ATPases isolated from the roots of cucumber seedlings activated by Mg+2 ions in experiments in vitro, were fairly distinctly inhibited by Ca-2 ions, very slightly inhibited by fluorides and molybdenum ions while NO3- anions had no effect on the level of ATPase activity studied. Introduction into the nutrient of 10-4 M Na2WO4 or 10-3 M Na VO3 (inhibitors of nitrate reductase NR distinctly inhibited activity of the ATPase under study especially of fractions IIa and III, and inhibited NR activity and lowered uptake of NO3-. WO4-2 and VO3 inhibited to the same extent absorption and reduction of NO3- in the initial phase of NR induction, whereas at a later stage both inhibitors checked reduction to a greater degree than uptake of NO3-. The results indicate the possibility of certain ATPase participation in assimilating nitrates, and suggest that in the initial stage of biosynthesis of the NR enzyme system, activity of the enzyme is distinctly dependent upon NO3- transport and the level of NR activity limited by the amount of nitrate taken up. At a later an additional mechanism of NO3- transport probably functions, not connected with simultaneous reduction of nitrates. On the basis of results the Butz and Jackson (1977 hypothesis concerning a model for the absorption and reduction of NO3- by plant tissues is discussed.

  2. [ALK inhibitor].

    Science.gov (United States)

    Mano, Hiroyuki

    2011-01-01

    While lung cancer is the leading cause of cancer deaths worldwide, the molecular mechanism underlying its carcinogenesis is mainly unknown. We have discovered a small, fusion-type tyrosine kinase EML4-ALK that is generated through a tiny inversion within the short arm of human chromosome 2. Transgenic mice expressing EML4-ALK in lung developed hundreds of lung cancer nodules soon after birth, but such nodules were readily eradicated upon treatment with an ALK inhibitor. Clinical trials for EML4-ALK-positive lung cancer with an ALK inhibitor is ongoing, with its interim results being highly promising.

  3. Nitrate and Nitrogen Oxides: Sources, Health Effects and Their Remediation.

    Science.gov (United States)

    Hakeem, Khalid Rehman; Sabir, Muhammad; Ozturk, Munir; Akhtar, Mohd Sayeed; Ibrahim, Faridah Hanum

    Increased use of nitrogenous (N) fertilizers in agriculture has significantly altered the global N-cycle because they release nitrogenous gases of environmental concerns. The emission of nitrous oxide (N2O) contributes to the global greenhouse gas accumulation and the stratospheric ozone depletion. In addition, it causes nitrate leaching problem deteriorating ground water quality. The nitrate toxicity has been reported in a number of studies showing the health hazards like methemoglobinemia in infants and is a potent cause of cancer. Despite these evident negative environmental as well as health impacts, consumption of N fertilizer cannot be reduced in view of the food security for the teeming growing world population. Various agronomic and genetic modifications have been practiced to tackle this problem. Some agronomic techniques adopted include split application of N, use of slow-release fertilizers, nitrification inhibitors and encouraging the use of organic manure over chemical fertilizers. As a matter of fact, the use of chemical means to remediate nitrate from the environment is very difficult and costly. Particularly, removal of nitrate from water is difficult task because it is chemically non-reactive in dilute aqueous solutions. Hence, the use of biological means for nitrate remediation offers a promising strategy to minimize the ill effects of nitrates and nitrites. One of the important goals to reduce N-fertilizer application can be effectively achieved by choosing N-efficient genotypes. This will ensure the optimum uptake of applied N in a balanced manner and exploring the molecular mechanisms for their uptake as well as metabolism in assimilatory pathways. The objectives of this paper are to evaluate the interrelations which exist in the terrestrial ecosystems between the plant type and characteristics of nutrient uptake and analyze the global consumption and demand for fertilizer nitrogen in relation to cereal production, evaluate the various methods

  4. Protective effect of dietary nitrate on experimental gastritis in rats.

    Science.gov (United States)

    Larauche, Muriel; Anton, Pauline M; Garcia-Villar, Rafaël; Theodorou, Vassilia; Frexinos, Jacques; Buéno, Lionel; Fioramonti, Jean

    2003-06-01

    Nitrates have long been considered as harmful dietary components and judged responsible for deleterious effects on human health, leading to stringent regulations concerning their levels in food and water. However, recent studies demonstrate that dietary nitrate may have a major role in human health as a non-immune mechanism for host defence, through its metabolism to NO in the stomach. NO is a versatile molecule and although evidence exists showing that administration of low doses of exogenous NO protects against gastrointestinal inflammation, higher NO doses have been shown to exacerbate injury. So, the effect of an ingestion of nitrates in doses corresponding to a normal diet in human consumers on an experimental gastritis induced by iodoacetamide in rats was investigated. During gastritis one of the following compounds was given orally: water; KNO3; the NO donor sodium nitroprusside; the NO scavenger haemoglobin given with either water or KNO3. N(G)-nitro-l-arginine methyl ester (l-NAME), a non-specific NO synthase inhibitor, was administered with either water, iodoacetamide alone, or combined with KNO3. After killing, the stomach was resected and microscopic damage scores, myeloperoxidase and NO synthase activities were determined. Iodoacetamide-induced gastritis was significantly reduced by KNO3 administration, an effect which was reproduced by sodium nitroprusside and reversed by haemoglobin. l-NAME induced gastric mucosal damage in itself, and KNO3 did not prevent the gastritis induced by iodoacetamide associated with l-NAME. In conclusion, dietary nitrate exerts a protective effect against an experimental gastritis in rats by releasing NO in the stomach but such an effect requires the production of endogenous NO.

  5. Angiogenesis Inhibitors

    Science.gov (United States)

    ... blood vessels “feed” growing tumors with oxygen and nutrients , allowing the cancer cells to invade nearby tissue , to move throughout ... any angiogenesis inhibitors currently being used to treat cancer in humans? Yes. The U.S. Food and Drug Administration (FDA) has approved bevacizumab to ...

  6. Microdamage induced calcium efflux from bone matrix activates intracellular calcium signaling in osteoblasts via L-type and T-type voltage-gated calcium channels.

    Science.gov (United States)

    Jung, Hyungjin; Best, Makenzie; Akkus, Ozan

    2015-07-01

    Mechanisms by which bone microdamage triggers repair response are not completely understood. It has been shown that calcium efflux ([Ca(2+)]E) occurs from regions of bone undergoing microdamage. Such efflux has also been shown to trigger intracellular calcium signaling ([Ca(2+)]I) in MC3T3-E1 cells local to damaged regions. Voltage-gated calcium channels (VGCCs) are implicated in the entry of [Ca(2+)]E to the cytoplasm. We investigated the involvement of VGCC in the extracellular calcium induced intracellular calcium response (ECIICR). MC3T3-E1 cells were subjected to one dimensional calcium efflux from their basal aspect which results in an increase in [Ca(2+)]I. This increase was concomitant with membrane depolarization and it was significantly reduced in the presence of Bepridil, a non-selective VGCC inhibitor. To identify specific type(s) of VGCC in ECIICR, the cells were treated with selective inhibitors for different types of VGCC. Significant changes in the peak intensity and the number of [Ca(2+)]I oscillations were observed when L-type and T-type specific VGCC inhibitors (Verapamil and NNC55-0396, respectively) were used. So as to confirm the involvement of L- and T-type VGCC in the context of microdamage, cells were seeded on devitalized notched bone specimen, which were loaded to induce microdamage in the presence and absence of Verapamil and NNC55-0396. The results showed significant decrease in [Ca(2+)]I activity of cells in the microdamaged regions of bone when L- and T-type blockers were applied. This study demonstrated that extracellular calcium increase in association with damage depolarizes the cell membrane and the calcium ions enter the cell cytoplasm by L- and T-type VGCCs. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Nitrates

    Science.gov (United States)

    ... cover all of the possible uses, warnings, side effects, or interactions with other medicines and vitamin or herbal supplements. ... you should check with your doctor. Common side effects: Dizziness Headaches Flushing of your face and neck Upset stomach or throwing up Low ...

  8. [Relationship between vegetable nutrition and nitrate content].

    Science.gov (United States)

    Li, Huihe; Wang, Zhengyin; Li, Baozhen

    2004-09-01

    Nitrate accumulation in vegetables, which related well to vegetable nutrition, becomes one of the limiting factors of non-pollution vegetables production. Preference to nitrate is the nutritional characteristic of vegetables. Nitrate is absorbed by vegetables through high-affinity transport system (HATS) and low-affinity transport system (LATS), and is reduced and transformed under the effect of such essential elements as molybdenum, manganese, iron, copper, sulphur and phosphorus. In this paper, the effects of essential elements on nitrate absorption and reductive transform were reviewed, and the relationships of nitrate accumulation in vegetables with vegetable nutrition of nitrogen, phosphorus, potassium and mid-and microelements as well as with balanced fertilization were discussed. The research keys in the field were prospected for controlling nitrate accumulation, improving vegetables' quality and producing non-pollution vegetables.

  9. Nitrate contamination of groundwater and its countermeasures

    Energy Technology Data Exchange (ETDEWEB)

    Mitamura, Hisayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The inevitable increases of food production and energy consumption with an increase in world population become main causes of an increase of nitrate load to the environment. Although nitrogen is essential for the growth of animal and plant as a constituent element of protein, excessive nitrate load to the environment contaminates groundwater resources used as drinking water and leads to seriously adverse effects on the health of man and livestock. In order to clarify the problem of nitrate contamination of groundwater and search a new trend of technology development from the viewpoint of environment remediation and protection, the present paper has reviewed adverse effects of nitrate on human health, the actual state of nitrogen cycle, several kinds of nitrate sources, measures for reducing nitrate level, etc. (author)

  10. Mechanisms of direct inhibition of the respiratory sulfate-reduction pathway by (per)chlorate and nitrate.

    Science.gov (United States)

    Carlson, Hans K; Kuehl, Jennifer V; Hazra, Amrita B; Justice, Nicholas B; Stoeva, Magdalena K; Sczesnak, Andrew; Mullan, Mark R; Iavarone, Anthony T; Engelbrektson, Anna; Price, Morgan N; Deutschbauer, Adam M; Arkin, Adam P; Coates, John D

    2015-06-01

    We investigated perchlorate (ClO(4)(-)) and chlorate (ClO(3)(-)) (collectively (per)chlorate) in comparison with nitrate as potential inhibitors of sulfide (H(2)S) production by mesophilic sulfate-reducing microorganisms (SRMs). We demonstrate the specificity and potency of (per)chlorate as direct SRM inhibitors in both pure cultures and undefined sulfidogenic communities. We demonstrate that (per)chlorate and nitrate are antagonistic inhibitors and resistance is cross-inducible implying that these compounds share at least one common mechanism of resistance. Using tagged-transposon pools we identified genes responsible for sensitivity and resistance in Desulfovibrio alaskensis G20. We found that mutants in Dde_2702 (Rex), a repressor of the central sulfate-reduction pathway were resistant to both (per)chlorate and nitrate. In general, Rex derepresses its regulon in response to increasing intracellular NADH:NAD(+) ratios. In cells in which respiratory sulfate reduction is inhibited, NADH:NAD(+) ratios should increase leading to derepression of the sulfate-reduction pathway. In support of this, in (per)chlorate or nitrate-stressed wild-type G20 we observed higher NADH:NAD(+) ratios, increased transcripts and increased peptide counts for genes in the core Rex regulon. We conclude that one mode of (per)chlorate and nitrate toxicity is as direct inhibitors of the central sulfate-reduction pathway. Our results demonstrate that (per)chlorate are more potent inhibitors than nitrate in both pure cultures and communities, implying that they represent an attractive alternative for controlling sulfidogenesis in industrial ecosystems. Of these, perchlorate offers better application logistics because of its inhibitory potency, solubility, relative chemical stability, low affinity for mineral cations and high mobility in environmental systems.

  11. Groundwater Head Control of Catchment Nitrate Export

    Science.gov (United States)

    Musolff, A.; Schmidt, C.; Rode, M.; Fleckenstein, J. H.

    2014-12-01

    Elevated nutrient fluxes from agricultural catchments affect downstream water resources. A method to assess nutrient fluxes is the evaluation of the export regime. The export regime classifies the relation between concentration and discharge and integrates mobilization as well as retention processes. Solutes can be exported chemostatically (variance of concentration regimes of nitrate in a series of neighboring sub-catchments of the Central German River Bode catchment. We found an accretion pattern of nitrate with increasing concentration when discharge is increasing and thus a chemodynamic export regime. Here we follow a nested approach and have a closer look at the controls of nitrate export in the small (1.4 km2) headwater catchment of the Sauerbach stream. The Sauerbach catchment is dominated by agricultural land use and is characterized by tile drains. We hypothesize that discharge as well as nitrate export is controlled by the groundwater head variability over time. To that end we follow a joint data analysis of discharge, groundwater heads and nitrate concentrations in groundwater, tile drains and surface water. At the gauging station the nitrate export is chemodynamic exhibiting the typical accretion pattern also found at the larger scale. Our data analysis shows that nitrate export regime is in two ways controlled by the depth to groundwater and the groundwater head variability: Discharge increases with increasing groundwater heads due to the activation of tile drains. On the other hand, depth to groundwater and passage through the unsaturated zone is the major control of aquifer nitrate concentration. At wells with larger depth to groundwater nitrate concentrations are significantly lower than at more shallow wells indicating retention processes in the unsaturated zone. Therefore the concentration in the stream increases with increasing heads since the activated tiles drain shallow groundwater with higher nitrate concentrations. We can thus show that the

  12. Development of a thresholding algorithm for calcium classification at multiple CT energies

    Science.gov (United States)

    Ng, LY.; Alssabbagh, M.; Tajuddin, A. A.; Shuaib, I. L.; Zainon, R.

    2017-05-01

    The objective of this study was to develop a thresholding method for calcium classification with different concentration using single-energy computed tomography. Five different concentrations of calcium chloride were filled in PMMA tubes and placed inside a water-filled PMMA phantom (diameter 10 cm). The phantom was scanned at 70, 80, 100, 120 and 140 kV using a SECT. CARE DOSE 4D was used and the slice thickness was set to 1 mm for all energies. ImageJ software inspired by the National Institute of Health (NIH) was used to measure the CT numbers for each calcium concentration from the CT images. The results were compared with a developed algorithm for verification. The percentage differences between the measured CT numbers obtained from the developed algorithm and the ImageJ show similar results. The multi-thresholding algorithm was found to be able to distinguish different concentrations of calcium chloride. However, it was unable to detect low concentrations of calcium chloride and iron (III) nitrate with CT numbers between 25 HU and 65 HU. The developed thresholding method used in this study may help to differentiate between calcium plaques and other types of plaques in blood vessels as it is proven to have a good ability to detect the high concentration of the calcium chloride. However, the algorithm needs to be improved to solve the limitations of detecting calcium chloride solution which has a similar CT number with iron (III) nitrate solution.

  13. Morphometric and microscopic evaluation of the effect of gallium nitrate as a root canal dressing in rat teeth submitted to late replantation Avaliação morfométrica e microscópica do efeito do nitrato de gálio usado como curativo intracanal em dentes de ratos reimplantados tardiamente

    Directory of Open Access Journals (Sweden)

    Graziela Garrido Mori

    2006-12-01

    Full Text Available The purpose of this study was to test a gallium nitrate solution, a resorption inhibitor, employed as a root canal dressing in teeth submitted to late replantation. Thirty maxillary right central incisors of rats were avulsed and kept dry for thirty minutes. The teeth were instrumented and the root surfaces were treated with 1% hypochlorite solution followed by application of 2% sodium fluoride. Thereafter, the teeth were divided into two groups according to the root canal dressing: Group I, solution of gallium nitrate; and Group II, calcium hydroxide paste. The teeth were then replanted in their respective sockets. The animals were killed at 15, 30 and 60 days after replantation and the samples were processed for morphometric and microscopic analysis. The results demonstrated that the gallium nitrate solution and the calcium hydroxide paste limited the root resorption, yet they did not impair its occurrence. It may be concluded that gallium nitrate solution and calcium hydroxide paste demonstrated similar performance.Este trabalho tem como objetivo testar a solução de nitrato de gálio, um inibidor da reabsorção, como curativo intracanal para dentes reimplantados tardiamente. Trinta incisivos centrais superiores direitos de ratos foram avulsionados e mantidos a seco por trinta minutos. Todos os dentes tiveram os canais radiculares instrumentados e a superfície radicular tratada com hipoclorito de sódio a 1%, seguido de fluoreto de sódio a 2%. Após isso, os dentes foram divididos em dois grupos de acordo com a medicação intracanal: no grupo I, foi usada solução de nitrato de gálio e grupo II, pasta de hidróxido de cálcio. Todos os dentes foram, então, reimplantados em seus respectivos alvéolos. Passados 15, 30 e 60 dias do reimplante, os animais foram sacrificados e as peças obtidas, processadas em laboratório para análise microscópica e morfométrica. Os resultados mostraram que a solução de nitrato de gálio e a pasta de

  14. Nitrate removal from water by ion exchange

    Directory of Open Access Journals (Sweden)

    Marija Nujić

    2017-01-01

    Full Text Available High concentrations of nitrate in water, both in surface and in groundwater, is a consequence of geological composition of soil or human activity. Increased concentrations of nitrate in drinking water is a serious hazard to human health, causing abnormalities such as cancerous growth in human digestion system, while excessive nitrate intake via drinking water can cause methemoglobinemia in infants. Furthermore, the presence of nitrate in aquifers can stimulate eutrophication, which compromise the growth of algae and depletion of dissolved oxygen. Natural and chemical fertilizers in crop production, detergent manufacturing, uncontrolled land discharge of municipal wastewater, and industrial wastes have been identified as the main sources of nitrate in water sources. Nitrate is a stable, highly soluble ion that is difficult to remove by conventional water treatment methods such as coagulation and flocculation. The ion exchange is the most widely used procedure for removing nitrate from water. In this research the possibility of removing nitrate from water was examined by using commercial ion exchangers: Duolite A7 and Relite A490, respectively. The influence of the initial concentration of nitrate (10, 50 and 100 mg/l, the contact time (15 - 1440 min and the mass of the ion exchanger (0.1 to 0.6 g was also examined.

  15. Measurement of isoprene nitrates by GCMS

    Science.gov (United States)

    Mills, Graham P.; Hiatt-Gipson, Glyn D.; Bew, Sean P.; Reeves, Claire E.

    2016-09-01

    According to atmospheric chemistry models, isoprene nitrates play an important role in determining the ozone production efficiency of isoprene; however this is very poorly constrained through observations as isoprene nitrates have not been widely measured. Measurements have been severely restricted largely due to a limited ability to measure individual isoprene nitrate isomers. An instrument based on gas chromatography/mass spectrometry (GCMS) and the associated calibration methods are described for the speciated measurements of individual isoprene nitrate isomers. Five of the primary isoprene nitrates which formed in the presence of NOx by reaction of isoprene with the hydroxyl radical (OH) in the Master Chemical Mechanism are identified using known isomers on two column phases and are fully separated on the Rtx-200 column. Three primary isoprene nitrates from the reaction of isoprene with the nitrate radical (NO3) are identified after synthesis from the already identified analogous hydroxy nitrate. A Tenax adsorbent-based trapping system allows the analysis of the majority of the known hydroxy and carbonyl primary isoprene nitrates, although not the (1,2)-IN isomer, under field-like levels of humidity and showed no impact from typical ambient concentrations of NOx and ozone.

  16. Nitrate reduction in sulfate-reducing bacteria.

    Science.gov (United States)

    Marietou, Angeliki

    2016-08-01

    Sulfate-reducing bacteria (SRBs) gain their energy by coupling the oxidation of organic substrate to the reduction of sulfate to sulfide. Several SRBs are able to use alternative terminal electron acceptors to sulfate such as nitrate. Nitrate-reducing SRBs have been isolated from a diverse range of environments. In order to be able to understand the significance of nitrate reduction in SRBs, we need to examine the ecology and physiology of the nitrate-reducing SRB isolates. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Administration of an angiotensin-converting enzyme inhibitor improves vascular function and urinary albumin excretion in low-risk essential hypertensive patients receiving anti-hypertensive treatment with calcium channel blockers. Organ-protecting effects independent of anti-hypertensive effect.

    Science.gov (United States)

    Watanabe, Yoshihiko; Takasugi, E; Shitakura, K; Okajima, K; Hota, N; Kubo, Y; Nunoda, S; Otsuka, K

    2011-01-01

    Concomitant administration of calcium channel blockers (CCBs) and angiotensin-converting enzyme inhibitors (ACEIs) to hypertensive patients at high risk for cardiovascular disease can prevent cardiovascular disease occurrence, but the effects of this treatment on renal and vascular function in low-risk hypertensive patients are unknown. The current study was an open-label prospective study. Hypertensive patients with no history of cardiovascular disease who had not met their blood pressure (BP) goals with CCB treatment were administered perindopril and followed for 6 months. Both home and office BP were significantly lowered by perindopril administration. The morning/evening (M/E) ratios calculated from home BP were 1.31 and 1.05 for systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively. When the patients were divided into two groups based on the presence or absence of an anti-hypertensive response, urinary albumin excretion, and cardio ankle vascular index were significantly reduced by perindopril administration in all the subjects, irrespective of the presence or absence of anti-hypertensive reaction. In low-risk hypertensive patients, perindopril improves renal and vascular function probably via its persistent anti-hypertensive effects and the concomitant effects of CCB.

  18. Calcium channel blocker poisoning

    Directory of Open Access Journals (Sweden)

    Miran Brvar

    2005-04-01

    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.

  19. Climate-induced changes in high elevation stream nitrate dynamics

    Science.gov (United States)

    Baron, J.S.; Schmidt, T.M.; Hartman, M.D.

    2009-01-01

    Mountain terrestrial and aquatic ecosystems are responsive to external drivers of change, especially climate change and atmospheric deposition of nitrogen (N). We explored the consequences of a temperature-warming trend on stream nitrate in an alpine and subalpine watershed in the Colorado Front Range that has long been the recipient of elevated atmospheric N deposition. Mean annual stream nitrate concentrations since 2000 are higher by 50% than an earlier monitoring period of 1991-1999. Mean annual N export increased by 28% from 2.03 kg N ha-1yr-1 before 2000 to 2.84 kg N ha-1yr-1 in Loch Vale watershed since 2000. The substantial increase in N export comes as a surprise, since mean wet atmospheric N deposition from 1991 to 2006 (3.06 kg N ha-1 yr-1) did not increase. There has been a period of below average precipitation from 2000 to 2006 and a steady increase in summer and fall temperatures of 0.12??C yr-1 in both seasons since 1991. Nitrate concentrations, as well as the weathering products calcium and sulfate, were higher for the period 2000-2006 in rock glacier meltwater at the top of the watershed above the influence of alpine and subalpine vegetation and soils. We conclude the observed recent N increases in Loch Vale are the result of warmer summer and fall mean temperatures that are melting ice in glaciers and rock glaciers. This, in turn, has exposed sediments from which N produced by nitrification can be flushed. We suggest a water quality threshold may have been crossed around 2000. The phenomenon observed in Loch Vale may be indicative of N release from ice features such as rock glaciers worldwide as mountain glaciers retreat. ?? 2009 Blackwell Publishing Ltd.

  20. Reactions between water-soluble organic acids and nitrates in atmospheric aerosols: Recycling of nitric acid and formation of organic salts

    Science.gov (United States)

    Wang, Bingbing; Laskin, Alexander

    2014-03-01

    Atmospheric particles often include a complex mixture of nitrate and secondary organic materials accumulated within the same individual particles. Nitrate as an important inorganic component can be chemically formed in the atmosphere. For instance, formation of sodium nitrate (NaNO3) and calcium nitrate (Ca(NO3)2) occurs when nitrogen oxides and nitric acid (HNO3) react with sea salt and calcite, respectively. Organic acids contribute a significant fraction of photochemically formed secondary organics that can condense on the preexisting nitrate-containing particles. Here we present a systematic microanalysis study on chemical composition of laboratory-generated particles composed of water-soluble organic acids and nitrates (i.e., NaNO3 and Ca(NO3)2) using computer-controlled scanning electron microscopy with energy-dispersive X-ray microanalysis and Fourier transform infrared microspectroscopy. The results show that water-soluble organic acids can react with nitrates and release gaseous HNO3 during the dehydration process. These reactions are attributed to acid displacement of nitrate with weak organic acids driven by the evaporation of HNO3 into gas phase because of its relatively high volatility. The reactions result in significant nitrate depletion and formation of organic salts in mixed organic acids/nitrate particles that, in turn, may affect their physical and chemical properties relevant to atmospheric environment and climate. Airborne nitrate concentrations are estimated by thermodynamic calculations corresponding to various nitrate depletions in selected organic acids of atmospheric relevance. The results indicate a potential mechanism of HNO3 recycling that may further affect concentrations of gas and condensed phase species in the atmosphere and the heterogeneous reaction chemistry between them.

  1. Effects of calcium paste as a seed coat on growth, yield and ...

    African Journals Online (AJOL)

    The present study was conducted to study the effect of coating the seeds with calcium paste before sowing, on plant growth, yield, the contents of some antioxidants and the activities of carbonic anhydrase and nitrate reductase in the Pisum sativum L. leaves under the influence of NaCl stress. NaCl stress reduced plant ...

  2. Ammonium nitrate fertiliser production based on biomass - environmental effects from a life cycle perspective.

    Science.gov (United States)

    Ahlgren, Serina; Baky, Andras; Bernesson, Sven; Nordberg, Ke; Norén, Olle; Hansson, Per-Anders

    2008-11-01

    Ammonium nitrate and calcium ammonium nitrate are the most commonly used straight nitrogen fertilisers in Europe, accounting for 43% of the total nitrogen used for fertilisers. They are both produced in a similar way; carbonate can be added as a last step to produce calcium ammonium nitrate. The environmental impact, fossil energy input and land use from using gasified biomass (cereal straw and short rotation willow (Salix) coppice) as feedstock in ammonium nitrate production were studied in a cradle-to-gate evaluation using life cycle assessment methodology. The global warming potential in the biomass systems was only 22-30% of the impact from conventional production using natural gas. The eutrophication potential was higher for the biomass systems due to nutrient leaching during cultivation, while the acidification was about the same in all systems. The primary fossil energy use was calculated to be 1.45 and 1.37MJ/kg nitrogen for Salix and straw, respectively, compared to 35.14MJ for natural gas. The biomass production was assumed to be self-supporting with nutrients by returning part of the ammonium nitrate produced together with the ash from the gasification. For the production of nitrogen from Salix, it was calculated that 3914kg of nitrogen can be produced every year from 1ha, after that 1.6% of the produced nitrogen has been returned to the Salix production. From wheat straw, 1615kg of nitrogen can be produced annually from 1ha, after that 0.6% of the nitrogen has been returned.

  3. 4-Methoxy-N,N′-diphenylbenzamidinium nitrate

    Directory of Open Access Journals (Sweden)

    Renata S. Silva

    2016-09-01

    Full Text Available The asymmetric unit of the title salt N,N′-diphenyl-4-methoxybenzamidinium nitrate, C20H19N2O+·NO3−, comprises two independent N,N′-diphenyl-4-methoxybenzamidinium cations and two nitrate anions. The crystal structure features N—H...O hydrogen bonds and C—H...O contacts responsible for the packing.

  4. Spectrophotometric Determination of Nitrate and Phosphate Levels ...

    African Journals Online (AJOL)

    MBI

    2013-04-09

    Apr 9, 2013 ... for drinking, it must meet certain physical, chemical and microbiological criteria set by international organizations such as World Health. Organization (APHA, 1989). Nitrate is a family of chemical compounds containing atoms of nitrogen and oxygen occurring naturally. Nitrate is critical to the continuation of.

  5. Nitrate dynamics in artificially drained nested watersheds

    Science.gov (United States)

    Billy, C.; Birgand, F.; Sebilo, M.; Billen, G.; Tournebize, J.; Kao, C.

    There is concern that subsurface drainage, by destroying or by-passing active denitrification areas, may prevent nitrate retention processes and enhance nitrate contamination of surface water by agriculture. To address this question, we studied the flow and concentration signatures of drainage waters and their transformations in a series of 5 nested watersheds, from 1 to 100 km 2 area, in the Brie region near Paris (France). At all scales, nitrate concentrations are generally higher during the winter drainage season compared to the low flow periods (late spring to early fall). High nitrate concentrations characterizing drainage waters are visible at the 1st, 2nd and 3rd stream order but are “diluted” by surface runoff from forested zones and buffered by groundwater contributions. The analysis of nitrate chemographs and nitrate budgets established for the different nested watersheds show significant nitrogen retention. Isotopic measurements indicate that the nitrate pool is enriched in δ 15N- NO3- as its concentration decreases. Direct estimation of benthic denitrification with benthic chambers allowed concluding that benthic denitrification is not the only retention mechanism and that “underground” denitrification, affecting nitrate on its way from the base of the root zone down to the limit of the river bed, may in fact dominate nitrogen retention processes even in this intensively drained watershed.

  6. Intravesical silver nitrate for refractory hemorrhagic cystitis.

    Science.gov (United States)

    Montgomery, Brian D; Boorjian, Stephen A; Ziegelmann, Matthew J; Joyce, Daniel D; Linder, Brian J

    2016-09-01

    Hemorrhagic cystitis is a challenging clinical entity with limited evidence available to guide treatment. The use of intravesical silver nitrate has been reported, though supporting literature is sparse. Here, we sought to assess outcomes of patients treated with intravesical silver nitrate for refractory hemorrhagic cystitis. We identified nine patients with refractory hemorrhagic cystitis treated at our institution with intravesical silver nitrate between 2000-2015. All patients had failed previous continuous bladder irrigation with normal saline and clot evacuation. Treatment success was defined as requiring no additional therapy beyond normal saline irrigation after silver nitrate instillation prior to hospital discharge. Median patient age was 80 years (IQR 73, 82). Radiation was the most common etiology for hemorrhagic cystitis 89% (8/9). Two patients underwent high dose (0.1%-0.4%) silver nitrate under anesthesia, while the remaining seven were treated with doses from 0.01% to 0.1% via continuous bladder irrigation for a median of 3 days (range 2-4). All nine patients (100%) had persistent hematuria despite intravesical silver nitrate therapy, requiring additional interventions and red blood cell transfusion during the hospitalization. There were no identified complications related to intravesical silver nitrate instillation. Although well tolerated, we found that intravesical silver nitrate was ineffective for bleeding control, suggesting a limited role for this agent in the management of patients with hemorrhagic cystitis.

  7. Spectrophotometric Determination of Nitrate in Vegetables Using ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    ABSTRACT: A rapid and sensitive spectrophotometric method for the determination of nitrate in vegetables is described. The method is based on the measurement of the absorbance of yellow sodium nitrophenoxide formed via the reaction of phenol with the vegetable-based nitrate in presence of sulphuric acid.

  8. Spectrophotometric determination of nitrate in vegetables using ...

    African Journals Online (AJOL)

    A rapid and sensitive spectrophotometric method for the determination of nitrate in vegetables is described. The method is based on the measurement of the absorbance of yellow sodium nitrophenoxide formed via the reaction of phenol with the vegetable-based nitrate in presence of sulphuric acid. The analytical ...

  9. 76 FR 46907 - Ammonium Nitrate Security Program

    Science.gov (United States)

    2011-08-03

    ..., killing hundreds and injuring thousands at the U.S. embassies in Dar es Salaam, Tanzania, and Nairobi... Congress has aided in evaluating many of the approaches contained in this NPRM. The Department's report can... will address the definition of ammonium nitrate. Congress has defined ammonium nitrate for purposes of...

  10. The crystal structure of urea nitrate

    NARCIS (Netherlands)

    Harkema, Sybolt; Feil, D.

    1969-01-01

    The structure of urea nitrate has been solved, by the use of three-dimensional X-ray data. Data were collected using Cu Ke and Mo K0~ radiations. The structure consists of layers with urea and nitrate groups held together by hydrogen bonds. The positions of all hydrogen atoms were found. The final R

  11. Microglass spheres in ammonium nitrate explosives

    OpenAIRE

    Y. Kazakov; G. Turesheva; Olga Golovchenko; N. Bergeneva; R. Seisembayev

    2010-01-01

    Developed consisting the explosive ammonium nitrate, paraffin and mikrosteklosfer. Due to the input of the explosive paraffin increased water resistance of explosives to 60 minutes. By entering into the explosive mikrosteklosfers been improved caking indices, since steklomikrosfers and paraffin was formed seal between the granules of ammonium nitrate.

  12. Microglass spheres in ammonium nitrate explosives

    Directory of Open Access Journals (Sweden)

    Y. Kazakov

    2010-03-01

    Full Text Available Developed consisting the explosive ammonium nitrate, paraffin and mikrosteklosfer. Due to the input of the explosive paraffin increased water resistance of explosives to 60 minutes. By entering into the explosive mikrosteklosfers been improved caking indices, since steklomikrosfers and paraffin was formed seal between the granules of ammonium nitrate.

  13. The contributions of nitrate uptake and efflux to isotope fractionation during algal nitrate assimilation

    Science.gov (United States)

    Karsh, K. L.; Trull, T. W.; Sigman, D. M.; Thompson, P. A.; Granger, J.

    2014-05-01

    In order to strengthen environmental application of nitrate N and O isotopes, we measured the N and O isotopic fractionation associated with cellular nitrate uptake and efflux in the nitrate-assimilating marine diatom Thalassiosira weissflogii. We isolated nitrate uptake and efflux from nitrate reduction by growing the cells in the presence of tungsten, which substitutes for molybdenum in assimilatory nitrate reductase, yielding an inactive enzyme. After growth on ammonium and then N starvation, cells were exposed to nitrate. Numerical models fit to the evolution of intracellular nitrate concentration and N and O isotopic composition yielded distinct N isotope effects (15ɛ) for nitrate uptake and nitrate efflux (2.0 ± 0.3‰ and 1.2 ± 0.4‰, respectively). The O isotope effects (18ɛ) for nitrate uptake and nitrate efflux were indistinguishable (2.8 ± 0.6‰), yielding a ratio of O to N isotopic fractionation for uptake of 1.4 ± 0.4 and for efflux of 2.3 ± 0.9. The 15ɛ for nitrate uptake can account for at most 40% of the organism-level N isotope effect (15ɛorg) measured in laboratory studies of T. weissflogii and in the open ocean (typically 5‰ or greater). This observation supports previous evidence that most isotope fractionation during nitrate assimilation is due to intracellular nitrate reduction, with nitrate efflux allowing the signal to be communicated to the environment. An O to N fractionation ratio (18ɛorg:15ɛorg) of ˜1 has been measured for nitrate assimilation in algal cultures and linked to the N and O isotope effects of nitrate reductase. Our results suggest that the ratios of O to N fractionation for both nitrate uptake and efflux may be distinct from a ratio of 1, to a degree that could cause the net 18ɛorg:15ɛorg to rise appreciably above 1 when 15ɛorg is low (e.g., yielding a ratio of 1.1 when 15ɛorg is 5‰). However, field and culture studies have consistently measured nearly equivalent fractionation of N and O isotopes in

  14. Nitrate reduction in an unconfined sandy aquifer

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Boesen, Carsten; Kristiansen, Henning

    1991-01-01

    Nitrate distribution and reduction processes were investigated in an unconfined sandy aquifer of Quaternary age. Groundwater chemistry was studied in a series of eight multilevel samplers along a flow line, deriving water from both arable and forested land. Results show that plumes of nitrate...... processes of O2 and NO3- occur at rates that are fast compared to the rate of downward water transport. Nitrate-contaminated groundwater contains total contents of dissolved ions that are two to four times higher than in groundwater derived from the forested area. The persistence of the high content...... of total dissolved ions in the NO3- free anoxic zone indicates the downward migration of contaminants and that active nitrate reduction is taking place. Nitrate is apparently reduced to N2 because both nitrite and ammonia are absent or found at very low concentrations. Possible electron donors...

  15. Linseed plus nitrate in the diet for fattening bulls: effects on methane emission, animal health and residues in offal.

    Science.gov (United States)

    Doreau, M; Arbre, M; Popova, M; Rochette, Y; Martin, C

    2018-03-01

    The combination of linseed and nitrate is known to decrease enteric methane emission in dairy cows but few studies have been carried out in fattening cattle for animal liveweight gain, enteric methane emission, animal health and presence of residues in beef products. To address this gap, 16 young bulls received a control (C) diet between weaning at 9 months and 14 months, then were split into two groups of eight balanced on feed intake, BW gain and methane emission to receive either the C diet or a diet moderately supplemented with extruded linseed and calcium nitrate (LN) for 2 months before being slaughtered. On a dry matter (DM) basis, the C diet contained 70% baled grass silage and 30% concentrate mainly made of maize, wheat and rapeseed meal. In the LN diet, rapeseed meal and a fraction of cereals were replaced by 35% extruded linseed and 6% calcium nitrate; linseed fatty acids and nitrate supply in the LN diet were 1.9% and 1.0%, respectively. Methane emission was measured continuously using the GreenFeed system. Methaemoglobin was determined every week in peripheral blood from bulls receiving the LN diet. Nitrate and nitrite concentrations were determined in rumen, liver and tongue sampled at slaughter. Dry matter intake tended to be lower for LN diet (P=0.10). Body weight gain was lower for LN diet (P=0.01; 1.60 and 1.26 kg/day for C and LN diet, respectively). Daily methane emission was 9% lower (Panimals and was always lower than 5.6%, suggesting an absence of risk to animal health. Nitrite and nitrate concentrations in offal did not differ between C and LN diets. In conclusion, a moderate supply of linseed and nitrate in bull feed failed to decrease enteric methane yield and impaired bull liveweight gain but without adverse effects for animal health and food safety.

  16. Respiratory Nitrate Ammonification by Shewanella oneidensis MR-1▿

    OpenAIRE

    Cruz-García, Claribel; Murray, Alison E.; Klappenbach, Joel A.; Stewart, Valley; Tiedje, James M.

    2006-01-01

    Anaerobic cultures of Shewanella oneidensis MR-1 grown with nitrate as the sole electron acceptor exhibited sequential reduction of nitrate to nitrite and then to ammonium. Little dinitrogen and nitrous oxide were detected, and no growth occurred on nitrous oxide. A mutant with the napA gene encoding periplasmic nitrate reductase deleted could not respire or assimilate nitrate and did not express nitrate reductase activity, confirming that the NapA enzyme is the sole nitrate reductase. Hence,...

  17. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

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

    2016-01-01

    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and inhibi...

  18. Calcium and bones

    Science.gov (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 ...

  19. Calcium D-saccharate

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  20. 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 ...

  1. A microstructural study of the degradation and calcium release from hydroxyapatite-calcium oxide ceramics made by infiltration.

    Science.gov (United States)

    Zhang, Qinghao; Schmelzer, Eva; Gerlach, Jörg C; Nettleship, Ian

    2017-04-01

    Hydroxyapatite pellets, partially densified in a low-temperature heat treatment, were infiltrated with calcium nitrate solution followed by in-situ precipitation of Ca(OH)2 and CaCO3. The infiltrated bodies were then densified to high relative density and the calcium carbonate transformed to calcium oxide during sintering and resulted in biphasic hydroxyapatite-CaO ceramics. This work investigated the influence of the infiltration on surface morphology, weight change, and microstructural-level degradation caused by exposure to saline at pH=7.4 and a temperature of 20°C. The CaO rendered the materials more susceptible to degradation, and released calcium into the saline faster than single phase, calcium deficient hydroxyapatite (HA) that were used as a control. In consequence, these ceramics could be used to release calcium into the culture microenvironments of bone tissue or bone marrow cells next to a scaffold surface. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Inhibition of large conductance calcium-dependent potassium ...

    African Journals Online (AJOL)

    We tested the hypothesis that Rho-kinase inhibits the large-conductance, calcium and voltage dependent potassium (BKCa) channels thereby promoting vasoconstriction. Our results show that the Rho-kinase inhibitor, Y-27632, induced concentration-dependent relaxation in rat mesenteric artery. The selective BKCa ...

  3. The effect of calcium on auxin depletion-induced tomato ...

    African Journals Online (AJOL)

    Yomi

    2012-10-09

    Oct 9, 2012 ... L-1 CaCl2) were applied to each set of dishes to estimate the function of calcium and the IAA transport inhibitor on abscission. One dish without any treatment served as the control. Fifty explants were inserted from the distal end into a Petri dish and ten of such dishes of explants were used as replicates.

  4. Tidal pumping facilitates dissimilatory nitrate reduction in intertidal marshes

    National Research Council Canada - National Science Library

    Zheng, Yanling; Hou, Lijun; Liu, Min; Liu, Zhanfei; Li, Xiaofei; Lin, Xianbiao; Yin, Guoyu; Gao, Juan; Yu, Chendi; Wang, Rong; Jiang, Xiaofen

    2016-01-01

    ...s. Intertidal sediments are important hotspots of dissimilatory nitrate reduction and interacting nitrogen cycling microorganisms, but the effect of tides on dissimilatory nitrate reduction, including...

  5. The effects of dietary nitrate, pH and temperature on nitrate reduction in the human oral cavity

    OpenAIRE

    Bojić Danijela V.; Bojić Aleksandar Lj.; Perović Jelica M.

    2004-01-01

    Dietary nitrate is metabolized to nitrite by bacterial flora on the posterior surface of the tongue leading to increased salivary nitrite concentrations. In the acidic environment in the stomach, nitrite forms nitrous acid, a potent nitro sating agent. The aim of this study was to examine the effects of dietary nitrate, pH and temperature on nitrate reduction in the human oral cavity. Nitrate reduction was monitored by nitrate reduction assay based on incubation of nitrate test solutions in t...

  6. Novel Peptide with Specific Calcium-Binding Capacity from Schizochytrium sp. Protein Hydrolysates and Calcium Bioavailability in Caco-2 Cells

    Directory of Open Access Journals (Sweden)

    Xixi Cai

    2016-12-01

    Full Text Available Peptide-calcium can probably be a suitable supplement to improve calcium absorption in the human body. In this study, a specific peptide Phe-Tyr (FY with calcium-binding capacity was purified from Schizochytrium sp. protein hydrolysates through gel filtration chromatography and reversed phase HPLC. The calcium-binding capacity of FY reached 128.77 ± 2.57 μg/mg. Results of ultraviolet spectroscopy, fluorescence spectroscopy, and infrared spectroscopy showed that carboxyl groups, amino groups, and amido groups were the major chelating sites. FY-Ca exhibited excellent thermal stability and solubility, which were beneficial to be absorbed and transported in the basic intestinal tract of the human body. Moreover, the calcium bioavailability in Caco-2 cells showed that FY-Ca could enhance calcium uptake efficiency by more than three times when compared with CaCl2, and protect calcium ions against dietary inhibitors, such as tannic acid, oxalate, phytate, and Zn2+. Our findings further the progress of algae-based peptide-calcium, suggesting that FY-Ca has the potential to be developed as functionally nutraceutical additives.

  7. Proteomic analysis of a rare urinary stone composed of calcium carbonate and calcium oxalate dihydrate: a case report.

    Science.gov (United States)

    Kaneko, Kiyoko; Matsuta, Yosuke; Moriyama, Manabu; Yasuda, Makoto; Chishima, Noriharu; Yamaoka, Noriko; Fukuuchi, Tomoko; Miyazawa, Katsuhito; Suzuki, Koji

    2014-03-01

    The objective of the present study was to investigate the matrix protein of a rare urinary stone that contained calcium carbonate. A urinary stone was extracted from a 34-year-old male patient with metabolic alkalosis. After X-ray diffractometry and infrared analysis of the stone, proteomic analysis was carried out. The resulting mass spectra were evaluated with protein search software, and matrix proteins were identified. X-ray diffraction and infrared analysis confirmed that the stone contained calcium carbonate and calcium oxalate dihydrate. Of the identified 53 proteins, 24 have not been previously reported from calcium oxalate- or calcium phosphate-containing stones. The protease inhibitors and several proteins related to cell adhesion or the cytoskeleton were identified for the first time. We analyzed in detail a rare urinary stone composed of calcium carbonate and calcium oxalate dihydrate. Considering the formation of a calcium carbonate stone, the new identified proteins should play an important role on the urolithiasis process in alkaline condition. © 2013 The Japanese Urological Association.

  8. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

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

    1993-01-01

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

  9. Effects of cropping system and rates of nitrogen in animal slurry and mineral fertilizer on nitrate leaching from a sandy loam

    DEFF Research Database (Denmark)

    Thomsen, Ingrid Kaag; Hansen, Jørgen Frederik; Kjellerup, Viggo K.

    1993-01-01

    Leaching of nitrate from a sandy loam cropped with spring barley, winter wheat and grass was compared in a 4-year lysimeter study. Crops were grown continuously or in a sequence including sugarbeet. Lysimeters were unfertilized or supplied with equivalent amounts of inorganic nitrogen in calcium...... ley of perennial ryegrass wheat grown in rotation wheat

  10. Photodegradation of Paracetamol in Nitrate Solution

    Science.gov (United States)

    Meng, Cui; Qu, Ruijuan; Liang, Jinyan; Yang, Xi

    2010-11-01

    The photodegradation of paracetamol in nitrate solution under simulated solar irradiation has been investigated. The degradation rates were compared by varying environmental parameters including concentrations of nitrate ion, humic substance and pH values. The quantifications of paracetamol were conducted by HPLC method. The results demonstrate that the photodegradation of paracetamol followed first-order kinetics. The photoproducts and intermediates of paracetamol in the presence of nitrate ions were identified by extensive GC-MS method. The photodegradation pathways involving. OH radicals as reactive species were proposed.

  11. Nitrate dry deposition measurements with surrogate surfaces

    Science.gov (United States)

    Zhu, Xiang

    Nitrate dry deposition is one of the most important topics in the study of the dry deposition of acidic and acidifying substances. This study measured nitrate dry deposition to (1) a water surface sampler (WSS) which was recently developed in the Department of Chemical and Environmental Engineering at Illinois Institute of Technology, (2) a Nylasorb filter on a knife-edge surrogate surface and (3) a greased strip on a knife-edge surrogate surface. Airborne nitric acid (HNO3), nitrous acid (HNO2), and nitrogen dioxide (NO2) concentrations were also measured concurrently with the flux measurements. These measurements were then used to evaluate the utility of using surrogate surfaces, and in particular the WSS, to measure nitrate dry deposition. The nitrogen containing species that may be responsible for nitrate dry deposition to the WSS include nitrogen monoxide (NO), NO2, peroxyacetyl nitrate (PAN), ammonia (NH3) and ammonium (NH4+), HNO2,/ HNO3, and particulate nitrate. Theoretical calculations and experiments showed that HNO3 and particulate nitrate appear to be the major nitrate contributors to the water surface sampler. Nitrate dry deposition to the water surface, Nylasorb filter and the greased strip were measured during the daytime in June and July 1995 and during both the day and night time in September and October 1995. The results showed that during the daytime in June and July the average nitrate dry deposition to the WSS (36.28 mg/m2-day) was much higher than that to the Nylasorb filter (14.04 mg/m2-day). However, during September and October there is no statistically significant difference in nitrate deposition flux between the WSS (average 4.59 mg/m2-day for the nighttime and 10.58 mg/m2-day for the daytime) and the Nylasorb filter (average 4.53 mg/m2-day for the nighttime and 8.87 mg/m2-day). A set of three experiments showed that particulate nitrate fluxes measured with the greased strip were underestimated due to the loss of volatile particulate

  12. Divergent action of calcium channel blockers on ATP-binding cassette protein expression.

    Science.gov (United States)

    Hasegawa, Kazuhiro; Wakino, Shu; Kanda, Takeshi; Yoshioka, Kyoko; Tatematsu, Satoru; Homma, Koichiro; Takamatsu, Ichiro; Sugano, Naoki; Hayashi, Koichi

    2005-12-01

    Calcium channel blockers (CCBs) are widely used in clinical practice, and have been reported to be effective in preventing the progression of atherosclerosis. We examined whether various types of calcium channel blockers affected the expression of ATP binding cassette transporter A1 (ABCA1), a factor contributing to anti-atherogenesis. Undifferentiated monocytic cell line, THP-1 cells were maintained in RPMI 1640 medium and treated with different kinds of calcium channel blockers. Among the calcium channel blockers tested, aranidipine and efonidipine increased ABCA1 protein expression without an increase in ABCA1 mRNA expression, whereas other calcium channel blockers (eg, nifedipine, amlodipine, and nicardipine) or T-type calcium channel blockers (eg, mibefradil and nickel chloride) failed to upregulate ABCA1 expression. H89, a protein kinase A inhibitor inhibited the aranidipine-induced ABCA1 protein expression, whereas genistein (a tyrosine kinase inhibitor), or AG490 (a JAK-2 inhibitor) had no effects. Neither of these inhibitors suppressed the efonidipine-induced ABCA1 protein expression. Intracellular cAMP levels were elevated only by aranidipine, but not by efonidipine. In conclusion, aranidipine and efonidipine have the ability to induce ABCA1 protein by distinct mechanisms; protein kinase A is involved in the aranidipine-induced ABCA1 upregulation. This non-class effect of calcium channel blockers may potentially offer beneficial action in the treatment of hypertensive subjects with atherosclerosis.

  13. Calcium sensing in exocytosis

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Wu, Bingbing; Han, Weiping

    2012-01-01

    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...

  14. Phase diagram of ammonium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Dunuwille, Mihindra; Yoo, Choong-Shik, E-mail: csyoo@wsu.edu [Department of Chemistry and Institute for Shock Physics, Washington State University, Pullman, Washington 99164 (United States)

    2013-12-07

    Ammonium Nitrate (AN) is a fertilizer, yet becomes an explosive upon a small addition of chemical impurities. The origin of enhanced chemical sensitivity in impure AN (or AN mixtures) is not well understood, posing significant safety issues in using AN even today. To remedy the situation, we have carried out an extensive study to investigate the phase stability of AN and its mixtures with hexane (ANFO–AN mixed with fuel oil) and Aluminum (Ammonal) at high pressures and temperatures, using diamond anvil cells (DAC) and micro-Raman spectroscopy. The results indicate that pure AN decomposes to N{sub 2}, N{sub 2}O, and H{sub 2}O at the onset of the melt, whereas the mixtures, ANFO and Ammonal, decompose at substantially lower temperatures. The present results also confirm the recently proposed phase IV-IV{sup ′} transition above 17 GPa and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400°C.

  15. Technical Report on Hydroxylamine Nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Harlow, Donald G. [Dept. of Energy (DOE), Washington DC (United States); Felt, Rowland E. [Dept. of Energy (DOE), Washington DC (United States); Agnew, Steve [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Barney, G. Scott [B& W Hanford Company, Richland, WA (United States); McKibben, J. Malvyn [Westinghouse Savannah River Company, Aiken, SC (United States); Garber, Robert [Parallax Inc., Rocklin, CA (United States); Lewis, Margie [Parallax Inc., Rocklin, CA (United States)

    1998-02-01

    This report presents the chemical properties and safe conditions for handling and storing solutions of hydroxylamine nitrate (HAN, NH2OH•HNO3 or NH3OH+) in nitric acid (HNO3). Section 1.0 summarizes the accidents experienced within the Department of Energy (DOE) weapons complex involving HAN or hydroxylamine sulfate (HAS), a chemical with similar properties. Section 2.0 describes past and current uses of HAN by DOE, the U.S. Military and foreign countries. Section 3.0 presents the basic chemistry of HAN, including chemical reaction and energy content equations. Section 4.0 provides experience and insights gained from previous uncontrolled reactions involving HAN and experimental data from Hanford & Savannah River Site (SRS). This information was used to develop safe conditions for the storage and handling of HAN as presented in Section 5.0. Section 6.0 summarizes recommendations for safe facility operations involving HAN and future research needs.

  16. 77 FR 65532 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice of Rescission of...

    Science.gov (United States)

    2012-10-29

    ... International Trade Administration Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice... the antidumping duty order on solid fertilizer grade ammonium nitrate (ammonium nitrate) from the... Administrative Review: Solid Fertilizer Grade Ammonium Nitrate (Ammonium Nitrate) from the Russian Federation...

  17. Mechanisms of Peroxynitrite Mediated Nitration of Tyrosine

    Science.gov (United States)

    Gunaydin, Hakan; Houk, K. N.

    2009-01-01

    The mechanisms of tyrosine nitration by peroxynitrous acid or nitrosoperoxycarbonate were investigated with the CBS-QB3 method. Either the protonation of peroxynitrite, or a reaction with carbon dioxide gives a reactive peroxide intermediate. Peroxynitrous acid mediated nitration of phenol occurs via the unimolecular decomposition to give nitrogen dioxide and hydroxyl radicals. Nitrosoperoxycarbonate also undergoes unimolecular decomposition to give carbonate and nitrogen dioxide radicals. The reactions of tyrosine with the hydroxyl or carbonate radicals give a phenoxy radical intermediate. The reaction of the nitrogen dioxide with this radical intermediate followed by tautomerization gives nitrated tyrosine in both cases. According to CBS-QB3 calculations, the rate-limiting step for the nitration of phenol is the decomposition of peroxynitrous acid or of nitrosoperoxycarbonate. PMID:19374346

  18. ROE Wet Nitrate Deposition 2011-2013

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 2011 to 2013. Summary data in this indicator were provided by EPA’s...

  19. [Nitrate concentrations in tap water in Spain].

    Science.gov (United States)

    Vitoria, Isidro; Maraver, Francisco; Sánchez-Valverde, Félix; Armijo, Francisco

    2015-01-01

    To determine nitrate concentrations in drinking water in a sample of Spanish cities. We used ion chromatography to analyze the nitrate concentrations of public drinking water in 108 Spanish municipalities with more than 50,000 inhabitants (supplying 21,290,707 potential individuals). The samples were collected between January and April 2012. The total number of samples tested was 324. The median nitrate concentration was 3.47 mg/L (range: 0.38-66.76; interquartile range: 4.51). The water from 94% of the municipalities contained less than 15 mg/L. The concentration was higher than 25mg/L in only 3 municipalities and was greater than 50mg/L in one. Nitrate levels in most public drinking water supplies in municipalities inhabited by almost half of the Spanish population are below 15 mg/L. Copyright © 2014 SESPAS. Published by Elsevier Espana. All rights reserved.

  20. Nitrate Waste Treatment Sampling and Analysis Plan

    Energy Technology Data Exchange (ETDEWEB)

    Vigil-Holterman, Luciana R. [Los Alamos National Laboratory; Martinez, Patrick Thomas [Los Alamos National Laboratory; Garcia, Terrence Kerwin [Los Alamos National Laboratory

    2017-07-05

    This plan is designed to outline the collection and analysis of nitrate salt-bearing waste samples required by the New Mexico Environment Department- Hazardous Waste Bureau in the Los Alamos National Laboratory (LANL) Hazardous Waste Facility Permit (Permit).

  1. Nitrate reduction in geologically heterogeneous catchments

    DEFF Research Database (Denmark)

    Refsgaard, Jens Christian; Auken, Esben; Bamberg, Charlotte A.

    2014-01-01

    In order to fulfil the requirements of the EU Water Framework Directive nitrate load from agricultural areas to surface water in Denmark needs to be reduced by about 40%. The regulations imposed until now have been uniform, i.e. the same restrictions for all areas independent of the subsurface...... conditions. Studies have shown that on a national basis about 2/3 of the nitrate leaching from the root zone is reduced naturally, through denitrification, in the subsurface before reaching the streams. Therefore, it is more cost-effective to identify robust areas, where nitrate leaching through the root...... the entire catchment. However, as distributed models often do not include local scale hydrogeological heterogeneities, they are typically not able to make accurate predictions at scales smaller than they are calibrated. We present a framework for assessing nitrate reduction in the subsurface...

  2. ROE Wet Nitrate Deposition 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 1989 to 1991. Summary data in this indicator were provided by EPA’s...

  3. Bone repair in calcium-deficient rats: comparison of xylitol+calcium carbonate with calcium carbonate, calcium lactate and calcium citrate on the repletion of calcium.

    Science.gov (United States)

    Hämäläinen, M M

    1994-06-01

    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.

  4. Calcium – how and why?

    Indian Academy of Sciences (India)

    Unknown

    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 ...

  5. Mechanisms of Peroxynitrite Mediated Nitration of Tyrosine

    OpenAIRE

    Gunaydin, Hakan; Houk, K. N.

    2009-01-01

    The mechanisms of tyrosine nitration by peroxynitrous acid or nitrosoperoxycarbonate were investigated with the CBS-QB3 method. Either the protonation of peroxynitrite, or a reaction with carbon dioxide gives a reactive peroxide intermediate. Peroxynitrous acid mediated nitration of phenol occurs via the unimolecular decomposition to give nitrogen dioxide and hydroxyl radicals. Nitrosoperoxycarbonate also undergoes unimolecular decomposition to give carbonate and nitrogen dioxide radicals. Th...

  6. Is beetroot juice more effective than sodium nitrate? The effects of equimolar nitrate dosages of nitrate-rich beetroot juice and sodium nitrate on oxygen consumption during exercise.

    Science.gov (United States)

    Flueck, Joelle Leonie; Bogdanova, Anna; Mettler, Samuel; Perret, Claudio

    2016-04-01

    Dietary nitrate has been reported to lower oxygen consumption in moderate- and severe-intensity exercise. To date, it is unproven that sodium nitrate (NaNO3(-); NIT) and nitrate-rich beetroot juice (BR) have the same effects on oxygen consumption, blood pressure, and plasma nitrate and nitrite concentrations or not. The aim of this study was to compare the effects of different dosages of NIT and BR on oxygen consumption in male athletes. Twelve healthy, well-trained men (median [minimum; maximum]; peak oxygen consumption: 59.4 mL·min(-1)·kg(-1) [40.5; 67.0]) performed 7 trials on different days, ingesting different nitrate dosages and placebo (PLC). Dosages were 3, 6, and 12 mmol nitrate as concentrated BR or NIT dissolved in plain water. Plasma nitrate and nitrite concentrations were measured before, 3 h after ingestion, and postexercise. Participants cycled for 5 min at moderate intensity and further 8 min at severe intensity. End-exercise oxygen consumption at moderate intensity was not significantly different between the 7 trials (p = 0.08). At severe-intensity exercise, end-exercise oxygen consumption was ~4% lower in the 6-mmol BR trial compared with the 6-mmol NIT (p = 0.003) trial as well as compared with PLC (p = 0.010). Plasma nitrite and nitrate concentrations were significantly increased after the ingestion of BR and NIT with the highest concentrations in the 12-mmol trials. Plasma nitrite concentration between NIT and BR did not significantly differ in the 6-mmol (p = 0.27) and in the 12-mmol (p = 0.75) trials. In conclusion, BR might reduce oxygen consumption to a greater extent compared with NIT.

  7. A search for nitrates in Martian meteorites

    Science.gov (United States)

    Grady, Monica M.; Wright, I. P.; Pillinger, C. T.

    1995-03-01

    Martian atmospheric nitrogen is highly enriched in N-15; nitrates formed by interaction of the atmosphere with the Martian regolith should therefore also be characterized by an elevated delta N-15 value. A search has been made for nitrates in two Martian meteorites, in order to determine the extent of possible regolith-atmosphere interaction. Shock-produced glass from the Elephant Moraine (EET) A79001 shergottite (E1,149) and a water-soluble extract from Nakhla were analyzed by Fourier transform infrared (FTIR) spectroscopy and stepped combustion-stable isotope mass spectrometry. FTIR of both meteorites had features at 1375/cm and 1630/cm, consistent with nitrates. On account of their low thermal stability, nitrates break down at temperatures below 600 C; in this temperature range, E1,149 yeilded approximately 1250 ppb nitrogen with delta N-15 -8 +/- 5%. If this nitrogen is from a nitrate, then it cannot be distinquished from terrestial salts by its isotopic composition. The water-soluble extract from Nakhla also released nitrogen at low temperatures, approximately 17 ppb with delta N-15 approximately -11 +/- 4%. Since Nakhla is an observed 'fall', this is unlikely to be a terrestial weathering product. Nitrates apparently occur in E1,149 and Nakhla, but in very low abundance, and their origin is unclear. The isotopic composition of the salts, which is within the range of that proposed for Martian magmatic volatiles, is far removed from that of nitrogen in the present-day Martian atmosphere. If the nitrates are Martian in origin, they did not form in recent times from reactions involving atmospheric gases. Rather, the nitrates could be the result of an earlier episode of atmospheric interaction with the regolith, or with implantation of magmatic volatiles introduced during degassing.

  8. Multiple mechanisms of nitrate sensing by Arabidopsis nitrate transceptor NRT1.1.

    Science.gov (United States)

    Bouguyon, E; Brun, F; Meynard, D; Kubeš, M; Pervent, M; Leran, S; Lacombe, B; Krouk, G; Guiderdoni, E; Zažímalová, E; Hoyerová, K; Nacry, P; Gojon, A

    2015-03-02

    In Arabidopsis the plasma membrane nitrate transceptor (transporter/receptor) NRT1.1 governs many physiological and developmental responses to nitrate. Alongside facilitating nitrate uptake, NRT1.1 regulates the expression levels of many nitrate assimilation pathway genes, modulates root system architecture, relieves seed dormancy and protects plants from ammonium toxicity. Here, we assess the functional and phenotypic consequences of point mutations in two key residues of NRT1.1 (P492 and T101). We show that the point mutations differentially affect several of the NRT1.1-dependent responses to nitrate, namely the repression of lateral root development at low nitrate concentrations, and the short-term upregulation of the nitrate-uptake gene NRT2.1, and its longer-term downregulation, at high nitrate concentrations. We also show that these mutations have differential effects on genome-wide gene expression. Our findings indicate that NRT1.1 activates four separate signalling mechanisms, which have independent structural bases in the protein. In particular, we present evidence to suggest that the phosphorylated and non-phosphorylated forms of NRT1.1 at T101 have distinct signalling functions, and that the nitrate-dependent regulation of root development depends on the phosphorylated form. Our findings add to the evidence that NRT1.1 is able to trigger independent signalling pathways in Arabidopsis in response to different environmental conditions.

  9. Calcium and Your Child

    Science.gov (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 ...

  10. Stoichiometry of Calcium Medicines

    Science.gov (United States)

    Pinto, Gabriel

    2005-01-01

    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.

  11. Magnesium, calcium and cancer

    National Research Council Canada - National Science Library

    Anghileri, Leopoldo J

    2009-01-01

    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...

  12. Nitrate Adsorption on Clay Kaolin: Batch Tests

    Directory of Open Access Journals (Sweden)

    Morteza Mohsenipour

    2015-01-01

    Full Text Available Soils possessing kaolin, gibbsite, goethite, and hematite particles have been found to have a natural capacity to attenuate pollution in aqueous phase. On the other hand, the hydroxyl group in soil increases anion exchange capacity under a low pH condition. The main objective of this paper was to evaluate effects of kaolin on nitrate reduction under acidic condition. In order to analyze the kaolin adsorption behaviour under various conditions, four different concentrations of nitrate, 45, 112.5, 225, and 450 mgNO3-/L, with a constant pH equal to 2, constant temperature equal to 25°C, and exposure period varying from 0 to 150 minutes were considered. The capacity of nitrate adsorption on kaolin has also been studied involving two well-known adsorption isotherm models, namely, Freundlich and Longmuir. The results revealed that approximately 25% of the nitrate present in the solution was adsorbed on clay kaolin. The laboratory experimental data revealed that Freundlich adsorption isotherm model was more accurate than Longmuir adsorption model in predicting of nitrate adsorption. Furthermore, the retardation factor of nitrate pollution in saturated zone has been found to be approximately 4 in presence of kaolin, which indicated that kaolin can be used for natural scavenger of pollution in the environment.

  13. Trace nitrate in oxic waters

    Science.gov (United States)

    Zafiriou, O. C.; Ball, L. A.; Hanley, Q.

    1992-08-01

    We describe a modified (Garside, 1982, Marine Chemistry, 11, 159-167) nitrite method that permits measurements down to subnanomolar concentrations and present datafrom Atlantic and Carribean deepwater profiles for comparison with a published Pacific section. This important intermediate in the nitrogen cycle was detected in all samples. Concentrations were consistently lowest (0.1-0.4 nM) in oligotrophic surface waters. Below 1 km, carribean and Southwest Sargasso sea nitrite concentrations were 0.4-1 nM, decreasing with increasing depth; reported Pacific [NO 2] averages are several times higher. Profiles in the upper kilometer beneath the classical primary nitrate maximum (PNM) were qualitatively similar, exhibiting a smooth supra-exponential drop with depth to vvalues of ˜1-4 nM at 1 km. Then nitrite inventory in this "tail" of the PNM above 1 km with 1 nM ≤[NO 2]≤50 nM roughly equals that in the classical PNM. Significant differences among profiles in the 0.1-1 km regionn are observed, consistent with nitrite pool turnover of 3-7 days estimated from Redfield stoichiometry and tritium-helium ages. Thus seasonal and/or regional variations in factors altering the nitrite production-consumption balance, rather than transport, seem to be responsible for nitrite variability. Nitrite profiles with anomalous midwater or near-bottom fine structure, including multi-point maxima and minima, were found along the Venezuelan continental margin and at ≈ 13°N. These featurers are tentatively ascribed to boundary effects, as hydrographic and circumstantial evidence suggests that these waters interacted previously with the bottom.

  14. Efficacy and safety of calcium channel blockers in heart failure : Focus on recent trials with second-generation dihydropyridines

    NARCIS (Netherlands)

    de Vries, RJM; van Veldhuisen, DJ; Dunselman, PHJM

    Background Chronic heart failure (CHF) has high morbidity and mortality rates despite treatment with angiotensin-converting-enzyme inhibitors, diuretics, and digoxin. Adjunctive-vasodilation through calcium channel blockade has been suggested as potentially useful, However, the first-generation

  15. Historical Tracking of Nitrate in Contrasting Vineyard Using Water Isotopes and Nitrate Depth Profiles

    Science.gov (United States)

    Sprenger, M.; Erhardt, M.; Riedel, M.; Weiler, M.

    2015-12-01

    The European Water Framework Directive (EWFD) aims to achieve a good chemical status for the groundwater bodies in Europe by the year 2015. Despite the effort to reduce the nitrate pollution from agriculture within the last two decades, there are still many groundwater aquifers that exceed nitrate concentrations above the EWFD threshold of 50 mg/l. Viticulture is seen as a major contributor of nitrate leaching and sowing of a green cover was shown to have a positive effect on lowering the nitrate loads in the upper 90 cm of the soil. However, the consequences for nitrate leaching into the subsoil were not yet tested. We analyzed the nitrate concentrations and pore water stable isotope composition to a depth of 380 cm in soil profiles under an old vineyard and a young vineyard with either soil tillage or permanent green cover in between the grapevines. The pore water stable isotopes were used to calibrate a soil physical model, which was then used to infer the age of the soil water at different depths. This way, we could relate elevated nitrate concentrations below an old vineyard to tillage processes that took place during the winter two years before the sampling. We further showed that the elevated nitrate concentration in the subsoil of a young vineyard can be related to the soil tillage prior to the planting of the new vineyard. If the soil is kept bare due to tillage, a nitrate concentration of 200 kg NO3--N/ha is found in 290 to 380 cm depth 2.5 years after the installation of the vineyard. The amount of nitrate leaching is considerably reduced due to a seeded green cover between the grapevines that takes up a high share of the mobilized nitrate reducing a potential contamination of the groundwater.

  16. Role of the organic matter in calcium oxalate lithiasis.

    Science.gov (United States)

    Grases, Felix; Isern, Bernat; Perello, Joan; Costa-Bauza, Antonia

    2005-05-01

    Urine contains variable amounts of organic matter derived from cell degradation. The cellular detritus is composed by membranous and cytosolic glycoproteins, etc. The aim of this paper was to study the role of organic matter in calcium oxalate crystal development and to evaluate the action of some crystallization inhibitors on this process. Crystallization studies were carried out on urine in stagnant urine as well as under flow conditions, in presence and absence of cellular debris. Low amounts of cellular debris (when batch conditions were used), exhibited some inhibitory activity on heterogeneous nucleation of calcium oxalate monohydrate crystals, probably due to glycoproteins. Increasing amounts of cellular debris, however, promoted the nucleation of calcium oxalate monohydrate crystals. When cellular debris was retained in a cavity with a urine flow, this organic matter effectively induced the development of primary aggregates of calcium oxalate monohydrate crystals (crystallization range 2.8 mg/h per mg of organic matter). Presence of crystallization inhibitors prevented or minimized crystal development. These findings show that cell debris provides the necessary elements for the development of oxalate crystals and that this process can be effectively inhibited by presence of crystallization inhibitors.

  17. Acetate biodegradation by anaerobic microorganisms at high pH and high calcium concentration

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Takahiro, E-mail: t-yoshida@rwmc.or.j [Central Research Institute of Electric Power Industry (CRIEPI), Nuclear Technology Research Laboratory, 2-11-1, Iwado-kita, Komae, Tokyo 201-8511 (Japan)

    2011-02-15

    Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic {sup 14}C compounds in cementitious repositories. Tamagawa river sediment or Teganuma pond sediment was anaerobically cultured with 5 mM acetate and 10 mM nitrate at pH 9.5-12 at 30 {sup o}C. After 20 and 90 days, the acetate concentration of the culture medium was analyzed and found to have decreased below 5 mM at pH {<=} 11. On the other hand, it did not decrease when either sediment was incubated in the absence of nitrate. These results suggest that nitrate-reducing bacteria can biodegrade acetate under more alkaline conditions than the reported pH range in which nitrate-reducing bacteria can exhibit activity. Acetate biodegradation was also examined at a high calcium concentration. Sediments were anaerobically cultured at pH 9.5 with 5 mM acetate and 10 mM nitrate in solution, equilibrated with ordinary Portland cement hydrate, in which the Ca concentration was 14.6 mM. No decrease in acetate concentration after incubation of the sediments was observed, nor was it lower than in the absence of cementitious composition, suggesting that kinetics of acetate biodegradation by anaerobic microorganisms is lowered by a high Ca concentration. - Research highlights: {yields} Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic {sup 14}C compounds in cementitious repositories. {yields} Nitrate-reducing bacteria can biodegrade acetate at pH {<=} 11. {yields} Kinetics of acetate biodegradation by anaerobic microorganisms might be lowered by a high Ca concentration.

  18. Effect of dietary nitrate level on enteric methane production, hydrogen emission, rumen fermentation, and nutrient digestibility in dairy cows.

    Science.gov (United States)

    Olijhoek, D W; Hellwing, A L F; Brask, M; Weisbjerg, M R; Højberg, O; Larsen, M K; Dijkstra, J; Erlandsen, E J; Lund, P

    2016-08-01

    Nitrate may lower methane production in ruminants by competing with methanogenesis for available hydrogen in the rumen. This study evaluated the effect of 4 levels of dietary nitrate addition on enteric methane production, hydrogen emission, feed intake, rumen fermentation, nutrient digestibility, microbial protein synthesis, and blood methemoglobin. In a 4×4 Latin square design 4 lactating Danish Holstein dairy cows fitted with rumen, duodenal, and ileal cannulas were assigned to 4 calcium ammonium nitrate addition levels: control, low, medium, and high [0, 5.3, 13.6, and 21.1g of nitrate/kg of dry matter (DM), respectively]. Diets were made isonitrogenous by replacing urea. Cows were fed ad libitum and, after a 6-d period of gradual introduction of nitrate, adapted to the corn-silage-based total mixed ration (forage:concentrate ratio 50:50 on DM basis) for 16d before sampling. Digesta content from duodenum, ileum, and feces, and rumen liquid were collected, after which methane production and hydrogen emissions were measured in respiration chambers. Methane production [L/kg of dry matter intake (DMI)] linearly decreased with increasing nitrate concentrations compared with the control, corresponding to a reduction of 6, 13, and 23% for the low, medium, and high diets, respectively. Methane production was lowered with apparent efficiencies (measured methane reduction relative to potential methane reduction) of 82.3, 71.9, and 79.4% for the low, medium, and high diets, respectively. Addition of nitrate increased hydrogen emissions (L/kg of DMI) quadratically by a factor of 2.5, 3.4, and 3.0 (as L/kg of DMI) for the low, medium, and high diets, respectively, compared with the control. Blood methemoglobin levels and nitrate concentrations in milk and urine increased with increasing nitrate intake, but did not constitute a threat for animal health and human food safety. Microbial crude protein synthesis and efficiency were unaffected. Total volatile fatty acid

  19. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

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

  20. [Microbial geochemical calcium cycle].

    Science.gov (United States)

    Zavarzin, G A

    2002-01-01

    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.

  1. An unexpected truth: increasing nitrate loading can decrease nitrate export from watersheds

    Science.gov (United States)

    Askarizadeh Bardsiri, A.; Grant, S. B.; Rippy, M.

    2015-12-01

    The discharge of anthropogenic nitrate (e.g., from partially treated sewage, return flows from agricultural irrigation, and runoff from animal feeding operations) to streams can negatively impact both human and ecosystem health. Managing these many point and non-point sources to achieve some specific end-point—for example, reducing the annual mass of nitrate exported from a watershed—can be a challenge, particularly in rapidly growing urban areas. Adding to this complexity is the fact that streams are not inert: they too can add or remove nitrate through assimilation (e.g., by stream-associated plants and animals) and microbially-mediated biogeochemical reactions that occur in streambed sediments (e.g., respiration, ammonification, nitrification, denitrification). By coupling a previously published correlation for in-stream processing of nitrate [Mulholland et al., Nature, 2008, 452, 202-205] with a stream network model of the Jacksons Creek watershed (Victoria, Australia) I demonstrate that managing anthropogenic sources of stream nitrate without consideration of in-stream processing can result in a number of non-intuitive "surprises"; for example, wastewater effluent discharges that increase nitrate loading but decrease in-stream nitrate concentrations can reduce the mass of nitrate exported from a watershed.

  2. Relationships between nitrate uptake and nitrate reductase activity in Cucumis sativus L.

    Directory of Open Access Journals (Sweden)

    Grażyna Kłobus

    2014-01-01

    Full Text Available Anti-NR IgG fragments obtained after papain digestion of polyclonal antibodies gave the positive immunological reaction with both, a soluble and plasma membrane-bound nitrate reductase. Anti-NR antibody as well as IgG fragments almost totally inhibited the nitrate reductase activity in cytosol proving a crossreaction of antibody with the catalytic site of a soluble NR. Anti-NR IgG fragments, but not undigested polyclonal antibodies affected the activity of the nitrate reductase associated with plasma membranes. Discrepancy in the action of intact antibodies and fragments obtained after they digestion were interpreted as a consequence of same differences in the ability of those molecules to the penetration through the membrane. Undigested anti-NR antibody have no effect on the nitrate uptake by intact plants, as well as by the right-side plasma membrane vesicles. On the other hand, IgG fragments of polyclonal antibodies abolished almost totally the nitrate uptake in the case of intact seedlings, but have only slight effect on the N03 uptake in plasma membranes. On the basis of above findings, some relations between nitrate uptake and its assimilation inside the cell are suggested. Since IgG fragments only slightly changed the N03 absorption in vesicles whereas the activity of plasmalemma associated nitrate reductase was strongly repressed, we concluded that the PM-NR is not structurally involved in the nitrate transport through the membrane.

  3. Peroxynitrite and protein nitration in the pathogenesis of diabetic peripheral neuropathy.

    Science.gov (United States)

    Stavniichuk, Roman; Shevalye, Hanna; Lupachyk, Sergey; Obrosov, Alexander; Groves, John T; Obrosova, Irina G; Yorek, Mark A

    2014-11-01

    Peroxynitrite, a product of the reaction of superoxide with nitric oxide, causes oxidative stress with concomitant inactivation of enzymes, poly(ADP-ribosylation), mitochondrial dysfunction and impaired stress signalling, as well as protein nitration. In this study, we sought to determine the effect of preventing protein nitration or increasing peroxynitrite decomposition on diabetic neuropathy in mice after an extended period of untreated diabetes. C57Bl6/J male control and diabetic mice were treated with the peroxynitrite decomposition catalyst Fe(III) tetramesitylporphyrin octasulfonate (FeTMPS, 10 mg/kg/day) or protein nitration inhibitor (-)-epicatechin gallate (20 mg/kg/day) for 4 weeks, after an initial 28 weeks of hyperglycaemia. Untreated diabetic mice developed motor and sensory nerve conduction velocity deficits, thermal and mechanical hypoalgesia, tactile allodynia and loss of intraepidermal nerve fibres. Both FeTMPS and epicatechin gallate partially corrected sensory nerve conduction slowing and small sensory nerve fibre dysfunction without alleviation of hyperglycaemia. Correction of motor nerve conduction deficit and increase in intraepidermal nerve fibre density were found with FeTMPS treatment only. Peroxynitrite injury and protein nitration are implicated in the development of diabetic peripheral neuropathy. The findings indicate that both structural and functional changes of chronic diabetic peripheral neuropathy can be reversed and provide rationale for the development of a new generation of antioxidants and peroxynitrite decomposition catalysts for treatment of diabetic peripheral neuropathy. Published in 2014. This article is a U.S. Government work and is in the public domain in the USA.

  4. Calcium orthophosphates in dentistry.

    Science.gov (United States)

    Dorozhkin, Sergey V

    2013-06-01

    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.

  5. Dependence of nitrate-induced oxalate accumulation on nitrate reduction in rice leaves.

    Science.gov (United States)

    Tian, Hua; Jiang, Linrong; Liu, Ee; Zhang, Jianjun; Liu, Fang; Peng, Xinxiang

    2008-06-01

    Oxalate, a common constituent in many plants, is known to play important functional roles in plants. However, excess levels of oxalate in edible parts of plants adversely affect their quality as food. Understanding the regulatory mechanism in plants, particularly in food crops, is of both scientific and practical significance. While a number of studies have shown that nitrate can efficiently induce oxalate accumulation in plants, how it elicits such an effect is not well understood. This study aimed to gain a further insight into the mechanism underlying the nitrate-induced oxalate accumulation. Nitrate-N efficiently caused oxalate accumulation in rice leaves, depending on the nitrate concentrations and treatment time. In contrast, same nitrogen molar levels of the other N forms such as nitrite, ammonium, glutamate and urea either had no effect on the accumulation or even reduced the oxalate level. When glutamate, glutamine, asparate and asparagine were added into the nutrient solution that already contained saturating concentration of nitrate, both oxalate levels and NR activity were correspondingly decreased. In all of these modes of treatment, the change in NR activity was positively paralleled to that in oxalate levels. For a further confirmation, we generated the transgenic rice plants with a NR interference gene introduced. The result further demonstrated that in the transgenic plants, unlike in wild-type plants, oxalate was no longer able to accumulate in response to the nitrate treatment even though the endogenous nitrate levels were substantially elevated. Taken together, our results suggest that the nitrate-induced oxalate accumulation in rice leaves is dependent on the NR-catalyzed nitrate reduction, rather than on nitrate itself or nitrite reduction or its downstream metabolites.

  6. The influence of Glyceria maxima and nitrate input on the composition and nitrate metabolism of the dissimilatory nitrate-reducing bacterial community

    NARCIS (Netherlands)

    Nijburg, J.W.; Laanbroek, H.J.

    1997-01-01

    The influence of nitrate addition and the presence of Glyceria maxima (reed sweetgrass) on the composition and nitrate metabolism of the dissimilatory nitrate-reducing bacterial community was investigated. Anoxic freshwater sediment was incubated in pots with or without G. maxima and with or without

  7. The influence of Glyceria maxima and nitrate input on the composition and nitrate metabolism of the dissimilatory nitrate-reducing bacterial community

    NARCIS (Netherlands)

    Nijburg, J.W.; Laanbroek, H.J.

    1997-01-01

    The influence of nitrate addition and the presence of Glyceria maxima (reed sweetgrass) on the composition and nitrate metabolism of the dissimilatory nitrate-reducing bacterial community was investigated. Anoxic freshwater sediment was incubated in pots with or without G. maxima and with or

  8. Effects of calcium source on biochemical properties of microbial CaCO3 precipitation

    Directory of Open Access Journals (Sweden)

    Jing eXu

    2015-12-01

    Full Text Available The biochemical properties of CaCO3 precipitation induced by Sporosarcina pasteurii, an ureolytic type microorganism, were investigated. Effects of calcium source on the precipitation process were examined, since calcium source plays a key role in microbiologically-induced mineralization. Regardless of the calcium source type, three distinct stages in the precipitation process were identified by Ca2+, NH4+, pH and cell density monitoring. Compared with stage 1 and 3, stage 2 was considered as the most critical part since biotic CaCO3 precipitation occurs during this stage. Kinetics studies showed that the microbial CaCO3 precipitation rate for calcium lactate was over twice of that for calcium nitrate, indicating that calcium lactate is more beneficial for the cell activity, which in turn determines urease production and CaCO3 precipitation. X-ray diffraction analysis confirmed the CaCO3 crystal as calcite, although scanning electron microscopy revealed a difference in crystal size and morphology if calcium source was different. The findings of this paper further suggest a promising application of microbiologically-induced CaCO3 precipitation in remediation of surface and cracks of porous media, e.g. cement-based composites, particularly by using organic source of calcium lactate.

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

    OpenAIRE

    Hajnóczky, György; Csordás, György

    2010-01-01

    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.

  10. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    Science.gov (United States)

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

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

  11. In vitro pharmacology of R 80122, a novel phosphodiesterase inhibitor

    NARCIS (Netherlands)

    Wilhelm, D.; Wilffert, B.; Janssens, W.J.; Leidig, A.; Meuter, C.; Ebbert, M.; Peters, Thies

    1992-01-01

    The cardiac in vitro effects of R 80122, a novel phosphodiesterase (PDE) inhibitor, were investigated and compared with those of the reference compound milrinone and of the calcium-sensitizer adibendan. In guinea pig left atria, both milrinone and R 80122 increased contractile force; 10 μM milrinone

  12. Proton Pump Inhibitor Use and the Antifracture Efficacy of Alendronate

    DEFF Research Database (Denmark)

    Abrahamsen, Bo; Eiken, Pia Agnete; Eastell, Richard

    2011-01-01

    Background: Proton pump inhibitors (PPIs) are widely used in elderly patients and are frequently coadministered in users of oral bisphosphonates. Biologically, PPIs could affect the absorption of calcium, vitamin B12, and bisphosphonates and could affect the osteoclast proton pump, thus interacting...

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

    DEFF Research Database (Denmark)

    Jensen, B L; Skøtt, O

    1994-01-01

    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...

  14. [Can nitrates lead to indirect toxicity?].

    Science.gov (United States)

    Hamon, M

    2007-09-01

    For many years, nitrates have been used, at low dosages, as an additive in salted food. New laws have been promulgated to limit their concentration in water due to increased levels found in soils, rivers and even the aquifer. Although nitrate ions themselves have not toxic properties, bacterial reduction into nitrite ions (occurring even in aqueous medium) can lead to nitrous anhydride, which in turn generates nitrosonium ions. Nitrosium ions react with secondary amine to give nitrosamines, many of which are cancer-inducing agents at very low doses. Opinions on this toxicity are clear-cut and difficult to reconcile. In fact, increased levels are due, in a large part, to the use of nitrates as fertiliéers but also to bacterial transformation of human and animal nitrogenous wastes such as urea.

  15. Excess nitrate loads to coastal waters reduces nitrate removal efficiency: mechanism and implications for coastal eutrophication.

    Science.gov (United States)

    Lunau, Mirko; Voss, Maren; Erickson, Matthew; Dziallas, Claudia; Casciotti, Karen; Ducklow, Hugh

    2013-05-01

    Terrestrial ecosystems are becoming increasingly nitrogen-saturated due to anthropogenic activities, such as agricultural loading with artificial fertilizer. Thus, more and more reactive nitrogen is entering streams and rivers, primarily as nitrate, where it is eventually transported towards the coastal zone. The assimilation of nitrate by coastal phytoplankton and its conversion into organic matter is an important feature of the aquatic nitrogen cycle. Dissolved reactive nitrogen is converted into a particulate form, which eventually undergoes nitrogen removal via microbial denitrification. High and unbalanced nitrate loads to the coastal zone may alter planktonic nitrate assimilation efficiency, due to the narrow stochiometric requirements for nutrients typically shown by these organisms. This implies a cascade of changes for the cycling of other elements, such as carbon, with unknown consequences at the ecosystem level. Here, we report that the nitrate removal efficiency (NRE) of a natural phytoplankton community decreased under high, unbalanced nitrate loads, due to the enhanced recycling of organic nitrogen and subsequent production and microbial transformation of excess ammonium. NRE was inversely correlated with the amount of nitrate present, and mechanistically controlled by dissolved organic nitrogen (DON), and organic carbon (Corg) availability. These findings have important implications for the management of nutrient runoff to coastal zones. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  16. Children's Bone Health and Calcium

    Science.gov (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 ...

  17. Nitrate Promotes Capsaicin Accumulation in Capsicum chinense Immobilized Placentas

    Science.gov (United States)

    Aldana-Iuit, Jeanny G.; Sauri-Duch, Enrique; Miranda-Ham, María de Lourdes; Castro-Concha, Lizbeth A.; Cuevas-Glory, Luis F.; Vázquez-Flota, Felipe A.

    2015-01-01

    In chili pepper's pods, placental tissue is responsible for the synthesis of capsaicinoids (CAPs), the compounds behind their typical hot flavor or pungency, which are synthesized from phenylalanine and branched amino acids. Placental tissue sections from Habanero peppers (Capsicum chinense Jacq.) were immobilized in a calcium alginate matrix and cultured in vitro, either continuously for 28 days or during two 14-day subculture periods. Immobilized placental tissue remained viable and metabolically active for up to 21 days, indicating its ability to interact with media components. CAPs contents abruptly decreased during the first 7 days in culture, probably due to structural damage to the placenta as revealed by scanning electron microcopy. CAPs levels remained low throughout the entire culture period, even though a slight recovery was noted in subcultured placentas. However, doubling the medium's nitrate content (from 40 to 80 mM) resulted in an important increment, reaching values similar to those of intact pod's placentas. These data suggest that isolated pepper placentas cultured in vitro remain metabolically active and are capable of metabolizing inorganic nitrogen sources, first into amino acids and, then, channeling them to CAP synthesis. PMID:25710024

  18. Nitrate Promotes Capsaicin Accumulation in Capsicum chinense Immobilized Placentas

    Directory of Open Access Journals (Sweden)

    Jeanny G. Aldana-Iuit

    2015-01-01

    Full Text Available In chili pepper’s pods, placental tissue is responsible for the synthesis of capsaicinoids (CAPs, the compounds behind their typical hot flavor or pungency, which are synthesized from phenylalanine and branched amino acids. Placental tissue sections from Habanero peppers (Capsicum chinense Jacq. were immobilized in a calcium alginate matrix and cultured in vitro, either continuously for 28 days or during two 14-day subculture periods. Immobilized placental tissue remained viable and metabolically active for up to 21 days, indicating its ability to interact with media components. CAPs contents abruptly decreased during the first 7 days in culture, probably due to structural damage to the placenta as revealed by scanning electron microcopy. CAPs levels remained low throughout the entire culture period, even though a slight recovery was noted in subcultured placentas. However, doubling the medium’s nitrate content (from 40 to 80 mM resulted in an important increment, reaching values similar to those of intact pod’s placentas. These data suggest that isolated pepper placentas cultured in vitro remain metabolically active and are capable of metabolizing inorganic nitrogen sources, first into amino acids and, then, channeling them to CAP synthesis.

  19. Stable prenucleation calcium carbonate clusters

    OpenAIRE

    Gebauer, Denis; Völkel, Antje; Cölfen, Helmut

    2008-01-01

    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...

  20. Exposure to extremely low frequency electromagnetic fields alters the calcium dynamics of cultured entorhinal cortex neurons.

    Science.gov (United States)

    Luo, Fen-Lan; Yang, Nian; He, Chao; Li, Hong-Li; Li, Chao; Chen, Fang; Xiong, Jia-Xiang; Hu, Zhi-An; Zhang, Jun

    2014-11-01

    Previous studies have revealed that extremely low frequency electromagnetic field (ELF-EMF) exposure affects neuronal dendritic spine density and NMDAR and AMPAR subunit expressions in the entorhinal cortex (EC). Although calcium signaling has a critical role in control of EC neuronal functions, however, it is still unclear whether the ELF-EMF exposure affects the EC neuronal calcium homeostasis. In the present study, using whole-cell recording and calcium imaging, we record the whole-cell inward currents that contain the voltage-gated calcium currents and show that ELF-EMF (50Hz, 1mT or 3mT, lasting 24h) exposure does not influence these currents. Next, we specifically isolate the high-voltage activated (HVA) and low-voltage activated (LVA) calcium channels-induced currents. Similarly, the activation and inactivation characteristics of these membrane calcium channels are also not influenced by ELF-EMF. Importantly, ELF-EMF exposure reduces the maximum amplitude of the high-K(+)-evoked calcium elevation in EC neurons, which is abolished by thapsigargin, a Ca(2+) ATPase inhibitor, to empty the intracellular calcium stores of EC neurons. Together, these findings indicate that ELF-EMF exposure specifically influences the intracellular calcium dynamics of cultural EC neurons via a calcium channel-independent mechanism. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Assay for calcium channels

    Energy Technology Data Exchange (ETDEWEB)

    Glossmann, H.; Ferry, D.R.

    1985-01-01

    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

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of full-disk images of the sun in Calcium (Ca) II K wavelength (393.4 nm). Ca II K imagery reveal magnetic structures of the sun from about 500...

  3. Demonstration of phosphates in calcium deposits: a modification of von Kossa's reaction.

    Science.gov (United States)

    Puchtler, H; Meloan, S N

    1978-07-12

    It has been suggested that in von Kóss'as technic silver cations replace calcium bound to phosphate or carbonate groups and are then reduced to black metallic silver during exposure to light. However, in test tube experiments silver phosphate retains its yellow color for days. These differences between reactions of pure calcium phosphates and calcium deposits in tissues were emphasized already by von Kóssa; he regarded only the initial yellow coloration of calcium diagnostic for calcium phosphates and deplored the subsequent blackening caused by organic compounds. Von Kóssa's experiments were easily reproducible. A review of the literature showed that reduction of silver nitrate by organic compounds was well known in the 19th century. For histochemical studies of phosphates it was deemed desirable to avoid the formation of black by-products. Sections of paraffin-embedded human tissues were exposed to solutions of silver nitrate in subdued light or darkness then treated with sodium thiosulfate. Silver phosphate was yellow to yellowish brown; other tissue structures remained colorless. No darkening was observed in sections stored for eight years. Other compounds which form yellow silver salts, e.g. iodides and periodates, are unlikely to occur in paraffin sections of human tissues.

  4. The Plasma Membrane Calcium Pump

    Science.gov (United States)

    Rasmussen, H.

    1983-01-01

    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.

  5. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

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

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...

  6. Impregnating Coal With Calcium Carbonate

    Science.gov (United States)

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

    1991-01-01

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

  7. Silver nitrate masquerading as a radiopaque foreign body.

    Science.gov (United States)

    Healy, Claragh; Canney, Mark; Murphy, Adrian; Regan, Padraic

    2007-04-01

    Silver nitrate is commonly used as a method of chemical cauterization to areas of hypergranulation. We report two cases wherein silver nitrate in the hand was misinterpreted radiologically as foreign bodies.

  8. Generation of nitryl chloride from chlorotrimethylsilane-acetyl nitrate ...

    Indian Academy of Sciences (India)

    Administrator

    amyl nitrate does not yield NO2Cl with silicon reagent. However, acetyl nitrate reacts successfully with chlorotrimethylsi- lane to give nitryl chloride, which is characterized by its UV spectrum. If it is generated in presence of ketoximes ...

  9. The effect of prolonged dietary nitrate supplementation on atherosclerosis development

    NARCIS (Netherlands)

    Marsch, Elke; Theelen, Thomas L.; Janssen, Ben J. A.; Briede, Jacco J.; Haenen, Guido R.; Senden, Joan M. G.; van Loon, Lucas J. C.; Poeze, Martijn; Bierau, Jörgen; Gijbels, Marion J.; Daemen, Mat J. A. P.; Sluimer, Judith C.

    2016-01-01

    Short term dietary nitrate or nitrite supplementation has nitric oxide (NO)-mediated beneficial effects on blood pressure and inflammation and reduces mitochondrial oxygen consumption, possibly preventing hypoxia. As these processes are implicated in atherogenesis, dietary nitrate was hypothesized

  10. 76 FR 70366 - Ammonium Nitrate Security Program

    Science.gov (United States)

    2011-11-14

    ... benefits of enabling AN Agents to provide AN Purchasers' identity verification information directly to... FURTHER INFORMATION CONTACT: Ammonium Nitrate Security Program Manager, U.S. Department of Homeland... additional information on public meeting facilities, information on access to those facilities for...

  11. Modular Regiospecific Synthesis of Nitrated Fatty Acids

    DEFF Research Database (Denmark)

    Hock, Katharina J.; Grimmer, Jennifer; Göbel, Dominik

    2016-01-01

    Endogenous nitrated fatty acids are an important class of signaling molecules. Herein a modular route for the efficient and regiospecific preparation of nitrooleic acids as well as various analogues is described. The approach is based on a simple set of alkyl halides as common building blocks...

  12. EFFECT OF AMMONIUM NITRATE SOLUTIONS ON ...

    African Journals Online (AJOL)

    EFFECT OF AMMONIUM NITRATE SOLUTIONS ON FERTILIZATION. AND DEVELOPMENT OF THE SEA URCHIN,. PARECHINUS ANGULOSUS. P. J. GREENWOOD & A. C. BROWN. Department o/Zoology, University o/Cape Town. ASTRACT. Eggs and sperm of Parechinus have been placed in sea water containing 1, ...

  13. Standoff Raman measurement of nitrates in water

    Science.gov (United States)

    Sadate, S.; Kassu, A.; Farley, C. W.; Sharma, A.; Hardisty, J.; Lifson, Miles T. K.

    2011-09-01

    The identification and real time detection of explosives and hazardous materials are of great interest to the Army and environmental monitoring/protection agencies. The application and efficiency of the remote Raman spectroscopy system for real time detection and identification of explosives and other hazardous chemicals of interest, air pollution monitoring, planetary and geological mineral analysis at various standoff distances have been demonstrated. In this paper, we report the adequacy of stand-off Raman system for remote detection and identification of chemicals in water using dissolved sodium nitrate and ammonium nitrate for concentrations between 200ppm and 5000ppm. Nitrates are used in explosives and are also necessary nutrients required for effective fertilizers. The nitrates in fertilizers are considered as potential sources of atmospheric and water pollution. The standoff Raman system used in this work consists of a 2-inch refracting telescope for collecting the scattered Raman light and a 785nm laser operating at 400mW coupled with a small portable spectrometer.

  14. Trend Analyses of Nitrate in Danish Groundwater

    DEFF Research Database (Denmark)

    Hansen, B.; Thorling, L.; Dalgaard, Tommy

    2012-01-01

    This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis of distribut......This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis...... of distribution, trends and trend reversals in the groundwater nitrate concentration. Secondly, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Thirdly, groundwater recharge CFC (Chlorofluorocarbon) age determination allows linking of the first...... two dataset. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater. Regulation and technical improvements in the intensive farming in Denmark have succeeded...

  15. Denitration of High Nitrate Salts Using Reductants

    Energy Technology Data Exchange (ETDEWEB)

    HD Smith; EO Jones; AJ Schmidt; AH Zacher; MD Brown; MR Elmore; SR Gano

    1999-05-03

    This report describes work conducted by Pacific Northwest National Laboratory (PNNL), in conjunction with Idaho National Engineering and Environmental Laboratory (INEEL), to remove nitrates in simulated low-activity waste (LAW). The major objective of this work was to provide data for identifying and demonstrating a technically viable and cost-effective approach to condition LAW for immobilization (grout).

  16. Spectrophotometric Determination of Nitrate in Vegetables Using ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    The method is based on the measurement of the absorbance of yellow sodium nitrophenoxide formed ... The high concentration of nitrogen in soil may lead to ... nitrate-nitrogen. The reaction is quantitative and analogous to that reported by Tanaka et al. (1982). JASEM ISSN 1119-8362. All rights reserved. J. Appl. Sci.

  17. Spectrophotometric Determination of Nitrate and Phosphate Levels ...

    African Journals Online (AJOL)

    Twelve drinking water samples from boreholes were collected from various sampling sites around the vicinity of Kura irrigated farmlands using polythene plastic containers and were analysed for the nitrate and phosphate levels using uV – visible spectrophotometer. From the results, it was found that all the samples had ...

  18. Nitrate induced anaemia in home dialysis patients

    Energy Technology Data Exchange (ETDEWEB)

    Salvadori, M.; Martinelli, F.; Comparini, L.; Bandini, S.; Sodi, A.

    1985-01-01

    Many home dialysis patients in Florence and the surrounding area suddenly showed an unusual anaemia. All used a softener for water treatment. They demonstrated methaemoglobinaemia, Heinz bodies and reduction in plasma haptoglobin indicating Hb oxidation. Tap water analysis showed excessive nitrates. The substitution of the softeners with deionisers solved this important and unusual clinical problem.

  19. Nitrate Salt Surrogate Blending Scoping Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-13

    Test blending equipment identified in the “Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing”. Determine if the equipment will provide adequate mixing of zeolite and surrogate salt/Swheat stream; optimize equipment type and operational sequencing; impact of baffles and inserts on mixing performance; and means of validating mixing performance

  20. The Path to Nitrate Salt Disposition

    Energy Technology Data Exchange (ETDEWEB)

    Funk, David John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-16

    The topic is presented in a series of slides arranged according to the following outline: LANL nitrate salt incident as thermal runaway (thermally sensitive surrogates, full-scale tests), temperature control for processing, treatment options and down selection, assessment of engineering options, anticipated control set for treatment, and summary of the overall steps for RNS.

  1. Evidence for a plasma-membrane-bound nitrate reductase involved in nitrate uptake of Chlorella sorokiniana

    Science.gov (United States)

    Tischner, R.; Ward, M. R.; Huffaker, R. C.

    1989-01-01

    Anti-nitrate-reductase (NR) immunoglobulin-G (IgG) fragments inhibited nitrate uptake into Chlorella cells but had no affect on nitrate uptake. Intact anti-NR serum and preimmune IgG fragments had no affect on nitrate uptake. Membrane-associated NR was detected in plasma-membrane (PM) fractions isolated by aqueous two-phase partitioning. The PM-associated NR was not removed by sonicating PM vesicles in 500 mM NaCl and 1 mM ethylenediaminetetraacetic acid and represented up to 0.8% of the total Chlorella NR activity. The PM NR was solubilized by Triton X-100 and inactivated by Chlorella NR antiserum. Plasma-membrane NR was present in ammonium-grown Chlorella cells that completely lacked soluble NR activity. The subunit sizes of the PM and soluble NRs were 60 and 95 kDa, respectively, as determined by sodium-dodecyl-sulfate electrophoresis and western blotting.

  2. Simultaneous removal of nitrate and hydrogen sulfide by autotrophic denitrification in nitrate-contaminated water treatment.

    Science.gov (United States)

    Liu, Yongjie; Chen, Nan; Liu, Ying; Liu, Hengyuan; Feng, Chuanping; Li, Miao

    2018-02-23

    Nitrate contamination is a risk to human health and may cause eutrophication, whereas H 2 S is an undesirable constituent in biogas. In order to better understand denitrification using gaseous H 2 S as electron donor, this study investigated denitrification at different molar ratios of sulfur and nitrogen (S/N ratios) and H 2 S dosages. Although nitrate continued to decrease, a lag in sulfate generation was observed, implying the generation of sulfide oxidizing intermediates, which accumulated even though nitrate was in excess at lower S/N ratios of 0.19 and 0.38. More addition of H 2 S could result in a longer lag of sulfate generation. Before depletion of dissolved sulfide, denitrification could proceed with little nitrite accumulation. High throughout sequencing analysis identified two major genera, Thiobacillus and Sulfurimonas, that were responsible for autotrophic denitrification. The simultaneous removal of nitrate and H 2 S using a wide range of concentrations could be able to be achieved.

  3. Impact of Sulfide on Nitrate Conversion in Eutrophic Nitrate-Rich Marine Sludge

    DEFF Research Database (Denmark)

    Schwermer, Carsten U.; Krieger, Bärbel; Lavik, Gaute

    2006-01-01

    and Environmental Sciences, Volcani Research Center, Bet-Dagan, Israel Multiple anaerobic processes are responsible for carbon mineralization in eutrophic nitrate-rich marine environments (e.g., upwelling areas, estuaries, and aquacultures), involving electron acceptors from both the nitrogen and sulfur cycle....... The interaction of these processes is less understood. Our aim was to investigate the functional interaction of nitrate reduction, denitrification and sulfate reduction in an anaerobic marine sludge. We hypothesize that sulfide (from sulfate reduction) (i) causes incomplete denitrification, and (ii) directs......, at the highest sulfide concentration tested (1.6 mM), only 22% and 20% of the nitrate added were converted to N2 and ammonium, respectively, while N2O became the main end product (56%). These findings were corroborated by pure culture experiments with nitrate-reducing and denitrifying isolates from the sludge...

  4. Proton pump inhibitors and osteoporosis

    DEFF Research Database (Denmark)

    Andersen, Bjarne Nesgaard; Johansen, Per Birger; Abrahamsen, Bo

    2016-01-01

    PURPOSE OF REVIEW: The purpose of the review is to provide an update on recent advances in the evidence based on proton pump inhibitors (PPI) as a possible cause of osteoporosis and osteoporotic fractures. This review focuses, in particular, on new studies published in the last 18 months and a di......PURPOSE OF REVIEW: The purpose of the review is to provide an update on recent advances in the evidence based on proton pump inhibitors (PPI) as a possible cause of osteoporosis and osteoporotic fractures. This review focuses, in particular, on new studies published in the last 18 months...... and a discussion of these findings and how this has influenced our understanding of this association, the clinical impact and the underlying pathophysiology. RECENT FINDINGS: New studies have further strengthened existing evidence linking use of PPIs to osteoporosis. Short-term use does not appear to pose a lower...... risk than long-term use. There is a continued lack of conclusive studies identifying the pathogenesis. Direct effects on calcium absorption or on osteoblast or osteoclast action cannot at present plausibly explain the mechanism. SUMMARY: The use of PPIs is a risk factor for development of osteoporosis...

  5. Benefits of Safer Drinking Water: The Value of Nitrate Reduction

    OpenAIRE

    Crutchfield, Stephen R.; Cooper, Joseph C.; Hellerstein, Daniel

    1997-01-01

    Nitrates in drinking water, which may come from nitrogen fertilizers applied to crops, are a potential health risk. This report evaluates the potential benefits of reducing human exposure to nitrates in the drinking water supply. In a survey, respondents were asked a series of questions about their willingness to pay for a hypothetical water filter, which would reduce their risk of nitrate exposure. If nitrates in the respondent's drinking water were to exceed the EPA minimum safety standard,...

  6. Identification of nitrate sources and discharge-depending nitrate dynamics in a mesoscale catchment

    Science.gov (United States)

    Mueller, Christin; Strachauer, Ulrike; Brauns, Mario; Musolff, Andreas; Kunz, Julia Vanessa; Brase, Lisa; Tarasova, Larisa; Merz, Ralf; Knöller, Kay

    2017-04-01

    During the last decades, nitrate concentrations in surface and groundwater have increased due to land use change and accompanying application of fertilizer in agriculture as well as increased atmospheric deposition. To mitigate nutrient impacts on downstream aquatic ecosystems, it is important to quantify potential nitrate sources, instream nitrate processing and its controls in a river system. The objective of this project is to characterize and quantify (regional) scale dynamics and trends in water and nitrogen fluxes of the entire Holtemme river catchment in central Germany making use of isotopic fingerprinting methods. Here we compare two key date sampling campaigns in 2014 and 2015, with spatially highly resolved measurements of discharge at 23 sampling locations including 11 major tributaries and 12 locations at the main river. Additionally, we have data from continuous runoff measurements at 10 locations operated by the local water authorities. Two waste water treatment plants contribute nitrogen to the Holtemme stream. This contribution impacts nitrate loads and nitrate isotopic signatures depending on the prevailing hydrological conditions. Nitrogen isotopic signatures in the catchment are mainly controlled by different sources (nitrified soil nitrogen in the headwater and manure/ effluents from WWTPs in the lowlands) and increase with raising nitrate concentrations along the main river. Nitrate loads at the outlet of the catchment are extremely different between both sampling campaigns (2014: NO3- = 97 t a-1, 2015: NO3- = 5 t a-1) which is associated with various runoff (2014: 0.8 m3 s-1, 2015: 0.2 m3 s-1). In 2015, the inflow from WWTP's raises the NO3- loads and enriches δ18O-NO3 values. Generally, oxygen isotope signatures from nitrate are more variable and are controlled by biogeochemical processes in concert with the oxygen isotopic composition of the ambient water. Elevated δ18O-NO3 in 2015 are most likely due to higher temperatures and lower

  7. Molten nitrate salt technology development status report

    Energy Technology Data Exchange (ETDEWEB)

    Carling, R.W.; Kramer, C.M.; Bradshaw, R.W.; Nissen, D.A.; Goods, S.H.; Mar, R.W.; Munford, J.W.; Karnowsky, M.M.; Biefeld, R.N.; Norem, N.J.

    1981-03-01

    Recognizing thermal energy storage as potentially critical to the successful commercialization of solar thermal power systems, the Department of Energy (DOE) has established a comprehensive and aggressive thermal energy storage technology development program. Of the fluids proposed for heat transfer and energy storage molten nitrate salts offer significant economic advantages. The nitrate salt of most interest is a binary mixture of NaNO/sub 3/ and KNO/sub 3/. Although nitrate/nitrite mixtures have been used for decades as heat transfer and heat treatment fluids the use has been at temperatures of about 450/sup 0/C and lower. In solar thermal power systems the salts will experience a temperature range of 350 to 600/sup 0/C. Because central receiver applications place more rigorous demands and higher temperatures on nitrate salts a comprehensive experimental program has been developed to examine what effects, if any, the new demands and temperatures have on the salts. The experiments include corrosion testing, environmental cracking of containment materials, and determinations of physical properties and decomposition mechanisms. This report details the work done at Sandia National Laboratories in each area listed. In addition, summaries of the experimental programs at Oak Ridge National Laboratory, the University of New York, EIC Laboratories, Inc., and the Norwegian Institute of Technology on molten nitrate salts are given. Also discussed is how the experimental programs will influence the near-term central receiver programs such as utility repowering/industrial retrofit and cogeneration. The report is designed to provide easy access to the latest information and data on molten NaNO/sub 3//KNO/sub 3/ for the designers and engineers of future central receiver projects.

  8. Production of citric and oxalic acids and solubilization of calcium phosphate by Penicillium bilaii.

    OpenAIRE

    Cunningham, J. E.; Kuiack, C

    1992-01-01

    An isolate of Penicillium bilaii previously reported to solubilize mineral phosphates and enhance plant uptake of phosphate was studied. Using agar media with calcium phosphate and the pH indicator alizarin red S, the influence of the medium composition on phosphate solubility and medium acidification was recorded. The major acidic metabolites produced by P. bilaii in a sucrose nitrate liquid medium were found to be oxalic acid and citric acid. Citric acid production was promoted under nitrog...

  9. Selective Nitrate Binding in Competitive Hydrogen Bonding Solvents: Do Anion–π Interactions Facilitate Nitrate Selectivity?**

    Science.gov (United States)

    Watt, Michelle M.; Zakharov, Lev N.

    2013-01-01

    New tripodal urea receptors demonstrate preferential binding of anions over competitive hydrogen bonding solvents. 1H NMR titrations in 10% DMSO-d6/CDCl3 show a higher affinity for nitrate over the halides for the fluorinated receptor, which is lost when the fluorines are removed. An “anion–π” interaction between the nitrate and the π-system of the ethynyl-substituted arene is proposed as the source of this selectivity. PMID:23939999

  10. Mammalian nitrate biosynthesis: mouse macrophages produce nitrite and nitrate in response to Escherichia coli lipopolysaccharide

    Energy Technology Data Exchange (ETDEWEB)

    Stuehr, D.J.; Marletta, M.A.

    1985-11-01

    Escherichia coli lipopolysaccharide (LPS)-induced nitrate biosynthesis was studied in LPS-sensitive C3H/He and LPS-resistant C3H/HeJ mice. Intraperitoneal injection of 15 ..mu..g of LPS led to a temporary 5- to 6-fold increase in blood nitrate concentration in the C3H/He strain. Levels of nitrate excreted in the urine were also increased. In contrast, no increase was observed in the C3H/HeJ strain with LPS injections up to 175 ..mu..g. Furthermore, thioglycolate-elicited peritoneal macrophages from C3H/He, but not from C3H/HeJ mice, produced nitrite (60%) and nitrate (40%) when cultured with LPS (10 ..mu..g/ml). T-lymphocyte addition/depletion experiments showed the presence of T cells enhanced this response. However, LPS did not cause nitrite or nitrate production in cultures of spleen lymphocytes from either strain. LPS-induced nitrate synthesis was also observed with nude mice and CBA/N mice, indicating that neither functional T lymphocytes nor LPS-responsive B lymphocytes were required for the response in vivo. This was consistent with the in vitro results showing macrophages alone were competent. Mycobacterium bovis infection of C3H/He and C3H/HeJ mice resulted in a large increase in nitrate production over the course of the infection for both strains, suggesting T-lymphocyte-mediated activation of macrophages as a potent stimulus for nitrate biosynthesis. The synthesis of nitrite is significant in that it can directly participate in the endogenous formation of nitrosamines and may also be involved in some aspect of the chemistry of cytotoxicity.

  11. Thromboxane-induced pulmonary vasoconstriction: involvement of calcium.

    Science.gov (United States)

    Farrukh, I S; Michael, J R; Summer, W R; Adkinson, N F; Gurtner, G H

    1985-01-01

    Infusion of tert-butyl hydroperoxide (t-bu-OOH) or arachidonic acid into rabbit pulmonary arteries stimulated thromboxane B2 (TxB2) production and caused pulmonary vasoconstriction. Both phenomena were blocked by cyclooxygenase inhibitors or a thromboxane synthase inhibitor. The increase in pulmonary arterial pressure caused by either t-bu-OOH or arachidonic acid infusion correlated with the concentration of TxB2 in the effluent perfusate. The concentration of TxB2 in the effluent perfusate, however, was always 10-fold greater after arachidonic acid infusion. In the rabbit pulmonary vascular bed lipoxygenase products did not appear involved in the vasoactive response to t-bu-OOH or exogenous arachidonic acid infusion. Calcium entry blockers or a calcium-free perfusate prevented the thromboxane-induced pulmonary vasoconstriction. Calmodulin inhibitors also blocked the pulmonary vasoconstriction induced by t-bu-OOH without affecting the production of TxB2 or prostacyclin. These results suggest that thromboxane causes pulmonary vasoconstriction by increasing cytosol calcium concentration.

  12. Occurrence of elevated nitrate in groundwaters of Krishna delta, India

    African Journals Online (AJOL)

    Nitrate concentrations were measured in the groundwater samples of Krishna delta, India. The results indicate a large variation of nitrate from 10 - 135 mg/l. In 79 groundwater samples, about 39% shows high nitrate contents (>50 mg/l), which is more than the permissible limits in drinking water. In north Krishna delta 49% ...

  13. Nitrate removal by electro-bioremediation technology in Korean soil

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jeong-Hee [Korea Electro technology Research Institute, Electric Power Research Division, Electrokinetics Research Group, 70 Boolmosangil, Changwon, 641-120 (Korea, Republic of); Maruthamuthu, Sundaram, E-mail: biocorrcecri@gmail.com [Korea Electro technology Research Institute, Electric Power Research Division, Electrokinetics Research Group, 70 Boolmosangil, Changwon, 641-120 (Korea, Republic of); Lee, Hyun-Goo; Ha, Tae-Hyun [Korea Electro technology Research Institute, Electric Power Research Division, Electrokinetics Research Group, 70 Boolmosangil, Changwon, 641-120 (Korea, Republic of); Bae, Jeong-Hyo, E-mail: jhbae@keri.re.kr [Korea Electro technology Research Institute, Electric Power Research Division, Electrokinetics Research Group, 70 Boolmosangil, Changwon, 641-120 (Korea, Republic of)

    2009-09-15

    The nitrate concentration of surface has become a serious concern in agricultural industry through out the world. In the present study, nitrate was removed in the soil by employing electro-bioremediation, a hybrid technology of bioremediation and electrokinetics. The abundance of Bacillus spp. as nitrate reducing bacteria were isolated and identified from the soil sample collected from a greenhouse at Jinju City of Gyengsangnamdo, South Korea. The nitrate reducing bacterial species were identified by 16 s RNA sequencing technique. The efficiency of bacterial isolates on nitrate removal in broth was tested. The experiment was conducted in an electrokinetic (EK) cell by applying 20 V across the electrodes. The nitrate reducing bacteria (Bacillus spp.) were inoculated in the soil for nitrate removal process by the addition of necessary nutrient. The influence of nitrate reducers on electrokinetic process was also studied. The concentration of nitrate at anodic area of soil was higher when compared to cathode in electrokinetic system, while adding bacteria in EK (EK + bio) system, the nitrate concentration was almost nil in all the area of soil. The bacteria supplies electron from organic degradation (humic substances) and enhances NO{sub 3}{sup -} reduction (denitrification). Experimental results showed that the electro-bio kinetic process viz. electroosmosis and physiological activity of bacteria reduced nitrate in soil environment effectively. Involvement of Bacillus spp. on nitrification was controlled by electrokinetics at cathode area by reduction of ammonium ions to nitrogen gas. The excellence of the combined electro-bio kinetics technology on nitrate removal is discussed.

  14. Nitrate in ground water of Beed City of Maharashtra (India).

    Science.gov (United States)

    Abdul Raheem, Shaikh; Husain, Sayyed; Farooqui, Mazahar

    2013-10-01

    An attempt was made to investigate the water pollution caused by nitrate in the ground water of Beed City of Maharashtra inIndia. The samples were collected randomly at different time periods from different places of Beed City and analysed for nitrate contents. The level of nitrate was found high and above permissible limit in the groundwater of the city.

  15. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    NARCIS (Netherlands)

    Balk, Melike; Laverman, A.M.; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought

  16. Nitrate concentration in drinking water supplies in selected ...

    African Journals Online (AJOL)

    Elevated levels of nitrate in drinking water have been associated with adverse health effects. Most susceptible to nitrate toxicity are infants under six months of age and pregnant women. This study assesses the nitrate concentration of 48 randomly selected wells in an urban-slum setting in Ibadan South East Local ...

  17. Nitrate pollution of Neogene alluvium aquifer in Morogoro ...

    African Journals Online (AJOL)

    Concern over nitrate pollution of groundwater in integrated water quality management has been growing recently. The levels of nitrate in wells from septic tanks and urban agriculture with nitrogen fertilizers application may increase the potential groundwater pollution by nitrate. The purpose of this study was to determine the ...

  18. A nitrate sensitive planar optode; performance and interferences

    DEFF Research Database (Denmark)

    Pedersen, Lasse; Dechesne, Arnaud; Smets, Barth F.

    2015-01-01

    We present a newly developed nitrate sensitive planar optode. It exhibits a linear response to nitrate from 1 to 50 mM at pH 8.0, a fast response time below 10 s and a good lifetime, allowing for fast two dimensional nitrate measurements over long periods of time. Interference from nitrite...

  19. Measuring nitrate and nitrite concentrations in vegetables, fruits in ...

    African Journals Online (AJOL)

    Nitrosamine is derived from nitrate and it seems as one of the factors and causes of gastrointestinal cancer in adults and Methemoglobinemia (blue baby syndrome). Eighty percent of nitrate enters to the body through vegetables and fruits, so in this study nitrate concentration in available vegetables and fruits at Shiraz was ...

  20. Regioselective nitration of aromatic substrates in zeolite cages

    Indian Academy of Sciences (India)

    Phenol is nitrated regioselectively by fuming nitric acid inside the cages of faujasite zeolites (dependent on the loading level) and a remarkable orthoselectivity is observed in solid state nitration. Toluene and chlorobenzene also containing ortho-/para-orienting substituents, undergo faster nitration, though the ...

  1. Nitrate to ammonia ceramic (NAC) bench scale stabilization study

    Energy Technology Data Exchange (ETDEWEB)

    Caime, W.J.; Hoeffner, S.L. [RUST - Clemson Technical Center, Anderson, SC (United States)

    1995-10-01

    Department of Energy (DOE) sites such as the Hanford site, Idaho National Engineering Laboratory (INEL), Savannah River site, Oak Ridge National Laboratory (ORNL) have large quantities of sodium-nitrate based liquid wastes. A process to reduce the nitrates to ammonia has been developed at ORNL. This technology creates a sludge lower in nitrates. This report describes stabilization possibilities of the sludge.

  2. Seasonal Distribution of Nitrate and Nitrite Levels in Eleme Abattoir ...

    African Journals Online (AJOL)

    MICHAEL

    should be periodic evaluation of nitrate and nitrite levels in the area. @ JASEM .... Table 6: Comparison of the levels of Nitrate and Nitrite in Surface and Groundwater in the Dry Season with WHO (1988) Standards. Unaffected ... Table 7: Calculated Ratios of Nitrate and Nitrite to WHO (1988) Guideline values. Season Ratios ...

  3. Nitrate concentration in greenhouse lettuce: a modelling study

    NARCIS (Netherlands)

    Seginer, I.; Buwalda, F.; Straten, van G.

    1998-01-01

    A simple two-state-variable model was developed to describe the nitrate concentration in lettuce when nitrate supply is unlimited. A central element of the model is a negative correlation between the concentrations of soluble carbohydrates and nitrate in the cell sap, a correlation which reflects

  4. Headache characteristics during the development of tolerance to nitrates

    DEFF Research Database (Denmark)

    Christiansen, I; Iversen, Helle Klingenberg; Olesen, J

    2000-01-01

    Recent studies suggest that nitric oxide (NO) plays an important role in nitrate-induced headache and in spontaneous migraine attacks. Organic nitrates act as prodrugs for NO and headache is a predominant adverse effect of nitrates but often disappears during continuous treatment. Insight...

  5. Optimum conditions for cotton nitrate reductase extraction and ...

    African Journals Online (AJOL)

    GREGO

    nitrate transformation into nitrite (µg of NO2. -/min/g F.W) is observed when incubation period of enzyme is short (1 to 5 min). Key words: Extraction, dosage, nitrate reductase activity, callus, cotton. INTRODUCTION. Nitrate reductase (EC. 1.7.99.4) is an oxidoreductase enzyme involved in nitrogen assimilation in plant. It.

  6. 78 FR 32690 - Certain Ammonium Nitrate From Ukraine

    Science.gov (United States)

    2013-05-31

    ... COMMISSION Certain Ammonium Nitrate From Ukraine Determination On the basis of the record \\1\\ developed in... antidumping duty order on certain ammonium nitrate from Ukraine would be likely to lead to continuation or... Publication 4396 (May 2013), entitled Certain Ammonium Nitrate from Ukraine: Investigation No. 731-TA-894...

  7. FLAME DENITRATION AND REDUCTION OF URANIUM NITRATE TO URANIUM DIOXIDE

    Science.gov (United States)

    Hedley, W.H.; Roehrs, R.J.; Henderson, C.M.

    1962-06-26

    A process is given for converting uranyl nitrate solution to uranium dioxide. The process comprises spraying fine droplets of aqueous uranyl nitrate solution into a hightemperature hydrocarbon flame, said flame being deficient in oxygen approximately 30%, retaining the feed in the flame for a sufficient length of time to reduce the nitrate to the dioxide, and recovering uranium dioxide. (AEC)

  8. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium... the provisions of this section. (a) Sodium nitrate-urea complex is a clathrate of approximately two...

  9. Calcium signaling in taste cells.

    Science.gov (United States)

    Medler, Kathryn F

    2015-09-01

    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.

  10. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, B.B.

    1995-08-01

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660{plus_minus}0.092 at 25 C, and extraction enthalpy is -5. 46{plus_minus}0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 {times} 10{sup 6}{plus_minus}3.56 {times} 10{sup 4} at 25 C; reaction enthalpy was -9.610{plus_minus}0.594 kcal/mol. Nitration complexation constant is 8.412{plus_minus}0.579, with an enthalpy of -10.72{plus_minus}1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured.

  11. Alpha glucosidase inhibitors

    National Research Council Canada - National Science Library

    Kalra, Sanjay

    2014-01-01

    Alpha glucosidase inhibitors (AGIs) are a unique class of anti-diabetic drugs. Derived from bacteria, these oral drugs are enzyme inhibitors which do not have a pancreato -centred mechanism of action...

  12. Proton pump inhibitors

    Science.gov (United States)

    Proton pump inhibitors (PPIs) are medicines that work by reducing the amount of stomach acid made by glands in ... Proton pump inhibitors are used to: Relieve symptoms of acid reflux, or gastroesophageal reflux disease (GERD). This is a ...

  13. Study on the Effect of Calcium and Potassium Spray on Date Bunch Fading Disorder

    Directory of Open Access Journals (Sweden)

    Hosein Shekofteh

    2017-02-01

    Full Text Available Introduction: Date bunch fading disorder has been one of the most important problems, which caused economic damage to date plantation area of Iran. It has been first reported on Mozafti cultivar in Kahnuj area, Kerman province. It has often been observed on soft and mid ripening cultivars such as Mozafti, Mordaseng and Kalote. Furthermore, it usually appears on Mozafti cultivar when fruits change from Khalal to Rutab stage. The most important symptoms of this disorder are sudden wilting of fruits and necrotic strips on the upper surface of the main bunch stalk. Incidence and development of these symptoms increase by high temperature, low relative humidity, and hot and dry wind. Several research studies have been carried out on this disorder so far, but the only research about the effect of nutrition on disorder was performed by Rosta (2003. The aim of the present study was to investigate the effect of calcium and potassium spray on date bunch fading and some traits of date fruit in Rigan region, Kerman province. Materials and Methods: The experiment was conducted based on randomized complete block designs with three replicates in Rigan located in east south of Kerman province, Iran, in 2012. Treatments were: T1: control, T2: spray of calcium nitrate at the concentration of 5 ppm, T3: spray of potassium sulfate at the concentration of 5 ppm, and T4: combined spray of calcium nitrate and potassium sulfate at the concentration of 5 ppm. Treatments were applied at Kimri, Hobabok and Khalal stages. Sampling was performed from 3 date palms (3 bunches from each date palm were selected randomly at the second date harvest. Totally, the traits of 200 fruits were measured in each date palm. The traits measured in the present study were: fruit length, fruit diameter, fruit weight, stone weight, stone diameter, and bunch fading percentage. Results and Discussions: According to the data of variance analysis, treatments had a significant effect on wet fruit

  14. Impact of calcium signaling during infection of Neisseria meningitidis to human brain microvascular endothelial cells.

    Science.gov (United States)

    Asmat, Tauseef M; Tenenbaum, Tobias; Jonsson, Ann-Beth; Schwerk, Christian; Schroten, Horst

    2014-01-01

    The pili and outer membrane proteins of Neisseria meningitidis (meningococci) facilitate bacterial adhesion and invasion into host cells. In this context expression of meningococcal PilC1 protein has been reported to play a crucial role. Intracellular calcium mobilization has been implicated as an important signaling event during internalization of several bacterial pathogens. Here we employed time lapse calcium-imaging and demonstrated that PilC1 of meningococci triggered a significant increase in cytoplasmic calcium in human brain microvascular endothelial cells, whereas PilC1-deficient meningococci could not initiate this signaling process. The increase in cytosolic calcium in response to PilC1-expressing meningococci was due to efflux of calcium from host intracellular stores as demonstrated by using 2-APB, which inhibits the release of calcium from the endoplasmic reticulum. Moreover, pre-treatment of host cells with U73122 (phospholipase C inhibitor) abolished the cytosolic calcium increase caused by PilC1-expressing meningococci demonstrating that active phospholipase C (PLC) is required to induce calcium transients in host cells. Furthermore, the role of cytosolic calcium on meningococcal adherence and internalization was documented by gentamicin protection assay and double immunofluorescence (DIF) staining. Results indicated that chelation of intracellular calcium by using BAPTA-AM significantly impaired PilC1-mediated meningococcal adherence to and invasion into host endothelial cells. However, buffering of extracellular calcium by BAPTA or EGTA demonstrated no significant effect on meningococcal adherence to and invasion into host cells. Taken together, these results indicate that meningococci induce calcium release from intracellular stores of host endothelial cells via PilC1 and cytoplasmic calcium concentrations play a critical role during PilC1 mediated meningococcal adherence to and subsequent invasion into host endothelial cells.

  15. Impact of calcium signaling during infection of Neisseria meningitidis to human brain microvascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Tauseef M Asmat

    Full Text Available The pili and outer membrane proteins of Neisseria meningitidis (meningococci facilitate bacterial adhesion and invasion into host cells. In this context expression of meningococcal PilC1 protein has been reported to play a crucial role. Intracellular calcium mobilization has been implicated as an important signaling event during internalization of several bacterial pathogens. Here we employed time lapse calcium-imaging and demonstrated that PilC1 of meningococci triggered a significant increase in cytoplasmic calcium in human brain microvascular endothelial cells, whereas PilC1-deficient meningococci could not initiate this signaling process. The increase in cytosolic calcium in response to PilC1-expressing meningococci was due to efflux of calcium from host intracellular stores as demonstrated by using 2-APB, which inhibits the release of calcium from the endoplasmic reticulum. Moreover, pre-treatment of host cells with U73122 (phospholipase C inhibitor abolished the cytosolic calcium increase caused by PilC1-expressing meningococci demonstrating that active phospholipase C (PLC is required to induce calcium transients in host cells. Furthermore, the role of cytosolic calcium on meningococcal adherence and internalization was documented by gentamicin protection assay and double immunofluorescence (DIF staining. Results indicated that chelation of intracellular calcium by using BAPTA-AM significantly impaired PilC1-mediated meningococcal adherence to and invasion into host endothelial cells. However, buffering of extracellular calcium by BAPTA or EGTA demonstrated no significant effect on meningococcal adherence to and invasion into host cells. Taken together, these results indicate that meningococci induce calcium release from intracellular stores of host endothelial cells via PilC1 and cytoplasmic calcium concentrations play a critical role during PilC1 mediated meningococcal adherence to and subsequent invasion into host endothelial cells.

  16. Calcium carbonate nucleation in an alkaline lake surface water, Pyramid Lake, Nevada, USA

    Science.gov (United States)

    Reddy, Michael M.; Hoch, Anthony

    2012-01-01

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

  17. DISTILLATION OF CALCIUM

    Science.gov (United States)

    Barton, J.

    1954-07-27

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

  18. Calcium metabolism and cardiovascular function after spaceflight

    Science.gov (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

    2002-01-01

    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.

  19. Sodium nitrate supplementation does not enhance performance of endurance athletes.

    Science.gov (United States)

    Bescós, Raúl; Ferrer-Roca, Ventura; Galilea, Pedro A; Roig, Andreu; Drobnic, Franchek; Sureda, Antoni; Martorell, Miquel; Cordova, Alfredo; Tur, Josep A; Pons, Antoni

    2012-12-01

    Supplementation with inorganic nitrate has been suggested to be an ergogenic aid for athletes as nitric oxide donor. The purpose of this study was to determine whether ingestion of inorganic sodium nitrate benefits well-trained athletes performing a 40-min exercise test in laboratory conditions. In addition, we investigated the effect of this supplement on plasma levels of endothelin-1 (ET-1) and in nitrated proteins. Thirteen trained athletes participated in this randomized, double-blind, crossover study. They performed a 40-min cycle ergometer distance-trial test after two 3-d periods of dietary supplementation with sodium nitrate (10 mg·kg of body mass) or placebo. Concentration of plasma nitrate (256 ± 35 μM) and nitrite (334 ± 86 nM) increased significantly (P nitrate supplementation compared with placebo (nitrate: 44 ± 11 μM; nitrite: 187 ± 43 nM). In terms of exercise performance, there were no differences in either the mean distance (nitrate: 26.4 ± 1.1 km; placebo: 26.3 ± 1.2 km; P = 0.61) or mean power output (nitrate: 258 ± 28 W; placebo: 257 ± 28 W; P = 0.89) between treatments. Plasma ET-1 increased significantly (P nitrate (4.0 ± 0.8 pg·mL) and placebo (2.4 ± 0.4 pg·mL) conditions. This increase was significantly greater (P nitrate group. Levels of nitrated proteins did not differ between treatments (nitrate: preexercise, 91% ± 23%; postexercise, 81% ± 23%; placebo: preexercise, 95% ± 20%; postexercise, 99% ± 19%). Sodium nitrate supplementation did not improve a 40-min distance-trial performance in endurance athletes. In addition, concentration of plasma ET-1 increased significantly after exercise after supplementation with sodium nitrate.

  20. Protein Tyrosine Nitration: Selectivity, physicochemical and biological consequences, denitration and proteomics methods for the identification of tyrosine-nitrated proteins

    NARCIS (Netherlands)

    Abello, N.; Kerstjens, H.A.M.; Postma, D.S; Bischoff, Rainer

    2009-01-01

    Protein tyrosine nitration (PTN) is a post-translational modification occurring under the action of a nitrating agent. Tyrosine is modified in the 3-position of the phenolic ring through the addition of a nitro group (NO2). In the present article, we review the main nitration reactions and elucidate

  1. Models of calcium signalling

    CERN Document Server

    Dupont, Geneviève; Kirk, Vivien; Sneyd, James

    2016-01-01

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

  2. Laboratory Column Experiments for Sequential Treatment of Nitrate and Phosphate in Groundwater

    Science.gov (United States)

    Jeen, S. W.; Jin, T. U.; Ha, J. H.

    2016-12-01

    Nitrogen and phosphorous are known as primary nutrients to cause eutrophication in surface water. Considering surface water and groundwater interactions, reduction in nutrients load from groundwater to surface water may alleviate possible outbreak of eutrophication. In this study, laboratory column experiments were performed to sequentially treat nitrate and phosphate in groundwater. Two columns were set up: the first column was targeted to treat nitrate using organic carbon materials and the second column was to treat phosphate using basic oxygen furnace (BOF) slag. The two columns were then connected to sequentially treat the two nutrients. The results showed that 20 mg/L NO3-N was completely reduced within 40 cm distance at a flow velocity of 20 cm/day through microbial denitrification process. Small amounts of nitrite and ammonia were detected, but the majority of nitrate is considered to be transformed to nitrogen gas. Phosphate (10 mg/L as PO4-P) was rapidly removed within less than 5 cm distance by phosphate mineral (e.g., hydroxyapatite) precipitation due to increases in pH, alkalinity, and calcium concentrations. When the two columns were sequentially connected, the general performances were similar to those when each column was assessed separately. However, additional phosphate removal in the first column was observed, possibly due to adsorption of phosphate onto the organic carbon materials. This study shows that nitrate and phosphate in groundwater can be effectively treated through passive treatment systems, such as permeable reactive barriers (PRBs), and they can contribute to reduction in nutrients load to surface water.

  3. Elemental calcium intake associated with calcium acetate/calcium carbonate in the treatment of hyperphosphatemia.

    Science.gov (United States)

    Wilson, Rosamund J; Copley, J Brian

    2017-01-01

    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.

  4. Open-Source Photometric System for Enzymatic Nitrate Quantification.

    Directory of Open Access Journals (Sweden)

    B T Wittbrodt

    Full Text Available Nitrate, the most oxidized form of nitrogen, is regulated to protect people and animals from harmful levels as there is a large over abundance due to anthropogenic factors. Widespread field testing for nitrate could begin to address the nitrate pollution problem, however, the Cadmium Reduction Method, the leading certified method to detect and quantify nitrate, demands the use of a toxic heavy metal. An alternative, the recently proposed Environmental Protection Agency Nitrate Reductase Nitrate-Nitrogen Analysis Method, eliminates this problem but requires an expensive proprietary spectrophotometer. The development of an inexpensive portable, handheld photometer will greatly expedite field nitrate analysis to combat pollution. To accomplish this goal, a methodology for the design, development, and technical validation of an improved open-source water testing platform capable of performing Nitrate Reductase Nitrate-Nitrogen Analysis Method. This approach is evaluated for its potential to i eliminate the need for toxic chemicals in water testing for nitrate and nitrite, ii reduce the cost of equipment to perform this method for measurement for water quality, and iii make the method easier to carryout in the field. The device is able to perform as well as commercial proprietary systems for less than 15% of the cost for materials. This allows for greater access to the technology and the new, safer nitrate testing technique.

  5. Nitrates in drinking water and the risk of death from brain cancer: does hardness in drinking water matter?

    Science.gov (United States)

    Ho, Chi-Kung; Yang, Ya-Hui; Yang, Chun-Yuh

    2011-01-01

    The objectives of this study were to (1) examine the relationship between nitrate levels in public water supplies and risk of death from brain cancer and (2) determine whether calcium (Ca) and magnesium (Mg) levels in drinking water might modify the influence of nitrates on development of brain cancer. A matched cancer case-control study was used to investigate the relationship between the risk of death from brain cancer and exposure to nitrates in drinking water in Taiwan. All brain cancer deaths of Taiwan residents from 2003 through 2008 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to cancer cases by gender, year of birth, and year of death. Information on the levels of nitrate-nitrogen (NO₃-N), Ca, and Mg in drinking water was obtained from Taiwan Water Supply Corporation (TWSC). The municipality of residence for cancer cases and controls was presumed to be the source of the subject's NO₃-N, Ca, and Mg exposure via drinking water. Relative to individuals whose NO₃-N exposure level was water with a NO₃-N exposure ≥ 0.38 ppm. No marked effect modification was observed due to Ca and Mg intake via drinking water on brain cancer occurrence.

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

    OpenAIRE

    Bizzozero, Julien; Scrivener, Karen

    2015-01-01

    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 ...

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

    OpenAIRE

    Verch, Andreas; Antonietti, Markus; Cölfen, Helmut

    2012-01-01

    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...

  8. Understanding nitrate assimilation and its regulation in microalgae.

    Science.gov (United States)

    Sanz-Luque, Emanuel; Chamizo-Ampudia, Alejandro; Llamas, Angel; Galvan, Aurora; Fernandez, Emilio

    2015-01-01

    Nitrate assimilation is a key process for nitrogen (N) acquisition in green microalgae. Among Chlorophyte algae, Chlamydomonas reinhardtii has resulted to be a good model system to unravel important facts of this process, and has provided important insights for agriculturally relevant plants. In this work, the recent findings on nitrate transport, nitrate reduction and the regulation of nitrate assimilation are presented in this and several other algae. Latest data have shown nitric oxide (NO) as an important signal molecule in the transcriptional and posttranslational regulation of nitrate reductase and inorganic N transport. Participation of regulatory genes and proteins in positive and negative signaling of the pathway and the mechanisms involved in the regulation of nitrate assimilation, as well as those involved in Molybdenum cofactor synthesis required to nitrate assimilation, are critically reviewed.

  9. Silver nanoparticles can attenuate nitrative stress

    Directory of Open Access Journals (Sweden)

    Mariusz Zuberek

    2017-04-01

    Full Text Available We have reported previously that glucose availability can modify toxicity of silver nanoparticles (AgNPs via elevation of antioxidant defence triggered by increased mitochondrial generation of reactive oxygen species. In this study, we examined the effect of glucose availability on the production of reactive nitrogen species in HepG2 cells and modification of nitrative stress by AgNPs. We found that lowering the glucose concentration increased expression of genes coding for inducible nitric oxide syntheas, NOS2 and NOS2A resulting in enhanced production of nitric oxide. Surprisingly, AgNPs decreased the level of nitric oxide accelerated denitration of proteins nitrated by exogenous peroxynitrite in cells grown in the presence of lowered glucose concentration, apparently due to further induction of protective proteins.

  10. Exogenous Calcium Enhances the Photosystem II Photochemistry Response in Salt Stressed Tall Fescue

    Directory of Open Access Journals (Sweden)

    Guangyang Wang

    2017-11-01

    Full Text Available Calcium enhances turfgrass response to salt stress. However, little is known about PSII photochemical changes when exogenous calcium was applied in salinity-stressed turfgrass. Here, we probe into the rearrangements of PSII electron transport and endogenous ion accumulation in tall fescue (Festuca arundinacea Schreber treated with exogenous calcium under salt stress. Three-month-old seedlings of genotype “TF133” were subjected to the control (CK, salinity (S, salinity + calcium nitrate (SC, and salinity + ethylene glycol tetraacetic acid (SE. Calcium nitrate and ethylene glycol tetraacetic acid was used as exogenous calcium donor and calcium chelating agent respectively. At the end of a 5-day duration treatment, samples in SC regime had better photochemistry performance on several parameters than salinity only. Such as the Area (equal to the plastoquinone pool size, N (number of QA- redox turnovers until Fm is reached, ψE0, or δRo (Efficiencdy/probability with which a PSII trapped electron is transferred from QA to QB or PSI acceptors, ABS/RC (Absorbed photon flux per RC. All the above suggested that calcium enhanced the electron transfer of PSII (especially beyond QA- and prevented reaction centers from inactivation in salt-stressed tall fescue. Furthermore, both grass shoot and root tissues generally accumulated more C, N, Ca2+, and K+ in the SC regime than S regime. Interrelated analysis indicated that ψE0, δRo, ABS/RC, C, and N content in shoots was highly correlated to each other and significantly positively related to Ca2+ and K+ content in roots. Besides, high salt increased ATP6E and CAMK2 transcription level in shoot at 1 and 5 day, respectively while exogenous calcium relieved it. In root, CAMK2 level was reduced by Salinity at 5 day and exogenous calcium recovered it. These observations involved in electron transport capacity and ion accumulation assist in understanding better the protective role of exogenous calcium in tall

  11. Impact of adding nitrate or increasing the lipid content of two contrasting diets on blood methaemoglobin and performance of two breeds of finishing beef steers.

    Science.gov (United States)

    Duthie, C-A; Rooke, J A; Troy, S; Hyslop, J J; Ross, D W; Waterhouse, A; Roehe, R

    2016-05-01

    Adding nitrate to the diet or increasing the concentration of dietary lipid are effective strategies for reducing enteric methane emissions. This study investigated their effect on health and performance of finishing beef cattle. The experiment was a two×two×three factorial design comprising two breeds (CHX, crossbred Charolais; LU, Luing); two basal diets consisting of (g/kg dry matter (DM), forage to concentrate ratios) 520 : 480 (Mixed) or 84 : 916 (Concentrate); and three treatments: (i) control with rapeseed meal as the main protein source replaced with either (ii) calcium nitrate (18 g nitrate/kg diet DM) or (iii) rapeseed cake (RSC, increasing acid hydrolysed ether extract from 25 to 48 g/kg diet DM). Steers (n=84) were allocated to each of the six basal diet×treatments in equal numbers of each breed with feed offered ad libitum. Blood methaemoglobin (MetHb) concentrations (marker for nitrate poisoning) were monitored throughout the study in steers receiving nitrate. After dietary adaptation over 28 days, individual animal intake, performance and feed efficiency were recorded for a test period of 56 days. Blood MetHb concentrations were low and similar up to 14 g nitrate/kg diet DM but increased when nitrate increased to 18 g nitrate/kg diet DM (P0.05). Neither basal diet nor treatment affected carcass quality (P>0.05), but CHX steers achieved a greater killing out proportion (Pdiet or increasing the level of dietary lipid through the use of cold-pressed RSC, did not adversely affect health or performance of finishing beef steers when used within the diets studied.

  12. 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

    2010-01-01

    [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...

  13. Localization of the calcium-regulated citrate transport process in proximal tubule cells.

    Science.gov (United States)

    Hering-Smith, Kathleen S; Mao, Weibo; Schiro, Faith R; Coleman-Barnett, Joycelynn; Pajor, Ana M; Hamm, L Lee

    2014-06-01

    Urinary citrate is an important inhibitor of calcium-stone formation. Most of the citrate reabsorption in the proximal tubule is thought to occur via a dicarboxylate transporter NaDC1 located in the apical membrane. OK cells, an established opossum kidney proximal tubule cell line, transport citrate but the characteristics change with extracellular calcium such that low calcium solutions stimulate total citrate transport as well as increase the apparent affinity for transport. The present studies address several fundamental properties of this novel process: the polarity of the transport process, the location of the calcium-sensitivity and whether NaDC1 is present in OK cells. OK cells grown on permeable supports exhibited apical >basolateral citrate transport. Apical transport of both citrate and succinate was sensitive to extracellular calcium whereas basolateral transport was not. Apical calcium, rather than basolateral, was the predominant determinant of changes in transport. Also 2,3-dimethylsuccinate, previously identified as an inhibitor of basolateral dicarboxylate transport, inhibited apical citrate uptake. Although the calcium-sensitive transport process in OK cells is functionally not typical NaDC1, NaDC1 is present in OK cells by Western blot and PCR. By immunolocalization studies, NaDC1 was predominantly located in discrete apical membrane or subapical areas. However, by biotinylation, apical NaDC1 decreases in the apical membrane with lowering calcium. In sum, OK cells express a calcium-sensitive/regulated dicarboxylate process at the apical membrane which responds to variations in apical calcium. Despite the functional differences of this process compared to NaDC1, NaDC1 is present in these cells, but predominantly in subapical vesicles.

  14. Analysis of nitrate reductase mRNA expression and nitrate reductase activity in response to nitrogen supply

    OpenAIRE

    Gholamreza Kavoosi; Sadegh Balotf; Homeira Eshghi; Hasan Hasani

    2014-01-01

    Nitrate is one of the major sources of nitrogen for the growth of plants. It is taken up by plant roots and transported to the leaves where it is reduced to nitrite in the. The main objective of this research was to investigate stimulatory effects of sodium nitrate, potassium nitrate, ammonia and urea on the production/generation of the nitrate reductase mRNA in Triticum aestivum plants. The plants were grown in standard nutrient solution for 21 days and then starved in a media without nitrat...

  15. Isomers of nitric acid and chlorine nitrate

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, M.P.; Francl, M.M.; Rowland, F.S.; Hehre, W.J.

    1988-09-22

    Ab initio molecular orbital calculations at the HF/6-31G* and MP2/6-31G* levels have been performed on nitric acid and chlorine nitrate. Equilibrium geometries and electric dipole moments obtained from the MP2/6-31G* calculations are in good agreement with the respective experimental values, normal-mode (harmonic) vibrational frequencies and frequency shifts due to isotopic substitution calculated at this level support the most recent gas-phase infrared assignments for chlorine nitrate but suggest a reversal in the assignment of v/sub 5/ and v/sub 6/ for nitric acid. Calculations at the same levels of theory were also performed on peroxynitrous acid (HOONO) and chlorine peroxynitrite (ClOONO). The former is found to be 35 kcal/mol less stable than nitric acid at the MP2/6-31G* level; chlorine peroxynitrite is 30 kcal/mol higher in energy than chlorine nitrate. The possible role of these high-energy isomers in atmospheric processes is discussed.

  16. Modulation of intracellular calcium levels by calcium lactate affects colon cancer cell motility through calcium-dependent calpain.

    Science.gov (United States)

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

    2015-01-01

    Cancer cell motility is a key phenomenon regulating invasion and metastasis. Focal adhesion kinase (FAK) plays a major role in cellular adhesion and metastasis of various cancers. The relationship between dietary supplementation of calcium and colon cancer has been extensively investigated. However, the effect of calcium (Ca2+) supplementation on calpain-FAK-motility is not clearly understood. We sought to identify the mechanism of FAK cleavage through Ca2+ bound lactate (CaLa), its downstream signaling and role in the motility of human colon cancer cells. We found that treating HCT116 and HT-29 cells with CaLa immediately increased the intracellular Ca2+ (iCa2+) levels for a prolonged period of time. Ca2+ influx induced cleavage of FAK into an N-terminal FAK (FERM domain) in a dose-dependent manner. Phosphorylated FAK (p-FAK) was also cleaved in to its p-N-terminal FAK. CaLa increased colon cancer cells motility. Calpeptin, a calpain inhibitor, reversed the effects of CaLa on FAK and pFAK cleavage in both cancer cell lines. The cleaved FAK translocates into the nucleus and modulates p53 stability through MDM2-associated ubiquitination. CaLa-induced Ca2+ influx increased the motility of colon cancer cells was mediated by calpain activity through FAK and pFAK protein destabilization. In conclusion, these results suggest that careful consideration may be given in deciding dietary Ca2+ supplementation to patient undergoing treatment for metastatic cancer.

  17. Nitrite and nitrate concentrations and metabolism in breast milk, infant formula, and parenteral nutrition.

    Science.gov (United States)

    Jones, Jesica A; Ninnis, Janet R; Hopper, Andrew O; Ibrahim, Yomna; Merritt, T Allen; Wan, Kim-Wah; Power, Gordon G; Blood, Arlin B

    2014-09-01

    Dietary nitrate and nitrite are sources of gastric NO, which modulates blood flow, mucus production, and microbial flora. However, the intake and importance of these anions in infants is largely unknown. Nitrate and nitrite levels were measured in breast milk of mothers of preterm and term infants, infant formulas, and parenteral nutrition. Nitrite metabolism in breast milk was measured after freeze-thawing, at different temperatures, varying oxygen tensions, and after inhibition of potential nitrite-metabolizing enzymes. Nitrite concentrations averaged 0.07 ± 0.01 μM in milk of mothers of preterm infants, less than that of term infants (0.13 ± 0.02 μM) (P parenteral nutrition were equivalent to or lower than those of breast milk. Freeze-thawing decreased nitrite concentration ~64%, falling with a half-life of 32 minutes at 37°C. The disappearance of nitrite was oxygen-dependent and prevented by ferricyanide and 3 inhibitors of lactoperoxidase. Nitrite concentrations in breast milk decrease with storage and freeze-thawing, a decline likely mediated by lactoperoxidase. Compared to adults, infants ingest relatively little nitrite and nitrate, which may be of importance in the modulation of blood flow and the bacterial flora of the infant GI tract, especially given the protective effects of swallowed nitrite. © 2013 American Society for Parenteral and Enteral Nutrition.

  18. Regulation of Nitrate Transport in Citrus Rootstocks Depending on Nitrogen Availability

    Science.gov (United States)

    Cerezo, Miguel; Camañes, Gemma; Flors, Víctor; Primo-Millo, Eduardo

    2007-01-01

    Previously, we reported that in Citrus plants, nitrate influx through the plasmalemma of roots cells follows a biphasic pattern, suggesting the existence of at least two different uptake systems, a high and low affinity transport system (HATS and LATS, respectively). Here, we describe a novel inducible high affinity transport system (iHATS). This new nitrate transport system has a high capacity to uptake nitrate in two different Citrus rootstocks (Cleopatra mandarin and Troyer citrange). The iHATS was saturable, showing higher affinity than constitutive high affinity transport system (cHATS) to the substrate NO3−. The Vmax for this saturable component iHATS was higher than cHATS, reaching similar values in both rootstocks. Additionally, we studied the regulation of root NO3− uptake mediated by both HATS (iHATS and cHATS) and LATS. In both rootstocks, cHATS is constitutive and independent of N-status. Concerning the regulation of iHATS, this system is upregulated by NO3− and down-regulated by the N status and by NO3− itself when plants are exposed to it for a longer period of time. LATS in Cleopatra mandarin and Troyer citrange rootstocks is repressed by the N-status. The use of various metabolic uncouplers or inhibitors indicated that NO3− net uptake mediated by iHATS and LATS was an active transport system in both rootstocks. PMID:19516998

  19. DETERMINATION OF CORROSION INHIBITOR CRITERIA FOR TYPE III IIIA TANKS DURING SALT DISSOLUTION OPERATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B

    2008-01-04

    Preparation of high level waste for vitrification involves in part the dissolution of salt cake from the carbon steel storage tanks. The salt crystals composing this cake are high in nitrate concentration with the interstitial liquid being high in hydroxide and nitrite concentration. During the salt dissolution process, a stage is reached in which the inhibitors, hydroxide and nitrite, are insufficient to prevent nitrate stress corrosion cracking (SCC) and fall outside the requirements of the corrosion control program. Additional inhibitors, which are necessary to meet the requirements, may be counterproductive to the efficiency of the process and waste minimization. Corrosion testing was initiated to better characterize the necessary inhibitor concentration for high nitrate waste during salt dissolution processing. A four-phase test program is being conducted: (1) electrochemical characterization, (2) accelerated or polarized U-bend testing, (3) long-term (non-polarized) U-bend testing and (4) vapor space U-bend tests. Electrochemical testing, which included cyclic potentiodynamic polarization (CPP), linear polarization resistance (LPR) and open-circuit potential (OCP) measurements, was performed to identify stress corrosion cracking susceptibility, to characterize pitting resistance and to determine the general corrosion rate. Polarized U-bend tests were utilized to assess the effect of minimum inhibitor concentrations and heat treatment on SCC and to determine test parameters for future long-term U-bend testing. Results from CPP, LPR and OCP tests demonstrated that carbon steel formed a protective oxide film and the potential became electropositive during exposure to the waste at all inhibitor concentrations. The tenacity of this film improved as the inhibitor concentration level was increased and the temperature was decreased. This passive film increased the resistance to localized corrosion significantly. Therefore if any of these inhibitor levels are selected

  20. Osteoporosis, calcium and physical activity.

    OpenAIRE

    Martin, A. D.; Houston, C S

    1987-01-01

    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...

  1. Cardiovascular Effects of Calcium Supplements

    Directory of Open Access Journals (Sweden)

    Ian R. Reid

    2013-07-01

    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.

  2. Laser Sintered Calcium Phosphate Bone

    National Research Council Canada - National Science Library

    Vail, Neil

    1999-01-01

    ...) 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...

  3. 21 CFR 73.1070 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 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...

  4. 21 CFR 184.1191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 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...

  5. Effect of honey on oxidation, chlorination and nitration by purified equine myeloperoxidase

    Directory of Open Access Journals (Sweden)

    Saad Aissat

    2017-09-01

    Full Text Available Objective: To evaluate the antioxidant effect of honey using two classical methods generally used, and for the first time to test the effect of honey on the oxidation, chlorination and nitration by purified equine myeloperoxidase (MPO. Methods: The antioxidant activity of three Algerian honey samples (nectar honey, mixed honey and honeydew honey was evaluated by two classical methods, the ferric- reducing/antioxidant power (FRAP assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH radical-scavenging capacity. Results: Honeydew honey had the highest reducing power and DPPH radical-scavenging activity, whereas nectar honey showed the lowest reducing power and DPPH radical-scavenging activity. All honey samples showed a significant inhibitory effect on the chlorination activity of equine MPO, but honeydew honey was the weakest inhibitor. The three samples were poorly inhibitor on the MPO oxidation and nitration activities, except for nectar honey that exerted an inhibitory effect at the highest tested concentration of 10%. These later results seem to contradict those obtained with DPPH and FRAP. Conclusions: The antioxidant capacity of honey is mainly due to the phenolic compounds and flavonoids it contained. It has been suggested that MPO might be involved in the antioxidant, not pro-oxidant, activity of phenolic compounds.

  6. Habitual Dietary Nitrate Intake in Highly Trained Athletes.

    Science.gov (United States)

    Jonvik, Kristin L; Nyakayiru, Jean; van Dijk, Jan-Willem; Wardenaar, Floris C; van Loon, Luc J C; Verdijk, Lex B

    2017-04-01

    Although beetroot juice, as a nitrate carrier, is a popular ergogenic supplement among athletes, nitrate is consumed through the regular diet as well. We aimed to assess the habitual dietary nitrate intake and identify the main contributing food sources in a large group of highly trained athletes. Dutch highly trained athletes (226 women and 327 men) completed 2-4 web-based 24-hr dietary recalls and questionnaires within a 2- to 4-week period. The nitrate content of food products and food groups was determined systematically based on values found in regulatory reports and scientific literature. These were then used to calculate each athlete's dietary nitrate intake from the web-based recalls. The median[IQR] habitual nitrate intake was 106[75-170] mg/d (range 19-525 mg/d). Nitrate intake correlated with energy intake (ρ = 0.28, p athletes (12.8[9.2-20.0] vs 9.4[6.2-13.8] mg/MJ; p athletes (150[88-236] vs 114[61-183] g/d; p athletes was 106 mg, with large interindividual variation. Dietary nitrate intake was strongly associated with the intake of vegetables. Increasing the intake of nitrate-rich vegetables in the diet might serve as an alternative strategy for nitrate supplementation.

  7. Growing patterns to produce 'nitrate-free' lettuce (Lactuca sativa).

    Science.gov (United States)

    Croitoru, Mircea Dumitru; Muntean, Daniela-Lucia; Fülöp, Ibolya; Modroiu, Adriana

    2015-01-01

    Vegetables can contain significant amounts of nitrate and, therefore, may pose health hazards to consumers by exceeding the accepted daily intake for nitrate. Different hydroponic growing patterns were examined in this work in order to obtain 'nitrate-free lettuces'. Growing lettuces on low nitrate content nutrient solution resulted in a significant decrease in lettuces' nitrate concentrations (1741 versus 39 mg kg(-1)), however the beneficial effect was cancelled out by an increase in the ambient temperature. Nitrate replacement with ammonium was associated with an important decrease of the lettuces' nitrate concentration (from 1896 to 14 mg kg(-1)) and survival rate. An economically feasible method to reduce nitrate concentrations was the removal of all inorganic nitrogen from the nutrient solution before the exponential growth phase. This method led to lettuces almost devoid of nitrate (10 mg kg(-1)). The dried mass and calcinated mass of lettuces, used as markers of lettuces' quality, were not influenced by this treatment, but a small reduction (18%, p < 0.05) in the fresh mass was recorded. The concentrations of nitrite in the lettuces and their modifications are also discussed in the paper. It is possible to obtain 'nitrate-free' lettuces in an economically feasible way.

  8. Nitrate removal using Brevundimonas diminuta MTCC 8486 from ground water.

    Science.gov (United States)

    Kavitha, S; Selvakumar, R; Sathishkumar, M; Swaminathan, K; Lakshmanaperumalsamy, P; Singh, A; Jain, S K

    2009-01-01

    Brevundimonas diminuta MTCC 8486, isolated from marine soil of coastal area of Trivandrum, Kerala, was used for biological removal of nitrate from ground water collected from Kar village of Pali district, Rajasthan. The organism was found to be resistance for nitrate up to 10,000 mg L(-1). The optimum growth conditions for biological removal of nitrate were established in batch culture. The effect of carbon sources on nitrate removal was investigated using mineral salt medium (MSM) containing 500 mg L(-1) of nitrate to select the most effective carbon source. Among glucose and starch as carbon source, glucose at 1% concentration increased the growth (182+/-8.24 x 10(4) CFU mL(-1)) and induced maximum nitrate reduction (86.4%) at 72 h. The ground water collected from Kar village, Pali district of Rajasthan containing 460+/-5.92 mg L(-1) of nitrate was subjected to three different treatment processes in pilot scale (T1 to T3). Higher removal of nitrate was observed in T2 process (88%) supplemented with 1% glucose. The system was scaled up to 10 L pilot scale treatment plant. At 72 h the nitrate removal was observed to be 95% in pilot scale plant. The residual nitrate level (23+/-0.41 mg L(-1)) in pilot scale treatment process was found to be below the permissible limit of WHO.

  9. Management of Nitrate m Groundwater: A Simulation Study

    Directory of Open Access Journals (Sweden)

    M. Ahmed

    2001-01-01

    Full Text Available Agriculture may cause nitrate and other chemicals to enter into groundwater systems. Nitrate in drinking water is considered a health hazard. A study was conducted to assess the extent of nitrate pollution of groundwater caused by agriculture and to evaluate the possibility of using the LEACHN model to manage nitrate entry into groundwater of agricultural areas of Al-Batinah, which is the most important agricultural region of Oman. Groundwater samples were collected and analyzed to assess the problem and to detect possible trends. Soil sampling and analyses were done to demonstrate the difference in the nitrate concentration in agricultural and non-agricultural soils. A questionnaire survey was conducted to gather information on agricultural practices, fertilizer input, and other possible sources of nitrate pollution. Results from the study show that 23% of groundwater samples have a concentration of nitrate-N concentration of 10 mg/l and 34% samples exceed 8 mg/l. Agricultural soils have higher levels of nitrate compared to non- agricultural soils. Results also demonstrate that nitrate levels in groundwater in Al-Batinah are rising. Application of the ‘LEACHN’ model demonstrated its suitability for use as a management tool to reduce nitrate leaching to groundwater by controlling fertilizer and water input.

  10. Role of Oxidative Stress in the Induction of Metallothionein-2A and Heme Oxygenase-1 Gene Expression by the Antineoplastic Agent Gallium Nitrate in Human Lymphoma Cells

    Science.gov (United States)

    Yang, Meiying; Chitambar, Christopher R.

    2008-01-01

    The mechanisms of action of gallium nitrate, an antineoplastic drug, are only partly understood. Using a DNA microarray to examine genes induced by gallium nitrate in CCRF-CEM cells, we found that gallium increased metallothionein-2A (MT2A) and heme oxygenase-1 (HO-1) gene expression and altered the levels of other stress-related genes. MT2A and HO-1 were increased after 6 and 16 h of incubation with gallium nitrate. An increase in oxidative stress, evidenced by a decrease in cellular GSH and GSH/GSSG ratio, and an increase in dichlorodihydrofluoroscein (DCF) fluorescence, was seen after 1 – 4 h incubation of cells with gallium nitrate. DCF fluorescence was blocked by the mitochondria-targeted antioxidant mitoquinone. N-acetyl-L-cysteine blocked gallium-induced MT2A and HO-1 expression and increased gallium’s cytotoxicity. Studies with a zinc-specific fluoroprobe suggested that gallium produced an expansion of an intracellular labile zinc pool, suggesting an action of gallium on zinc homeostasis. Gallium nitrate increased the phosphorylation of p38 mitogen-activated protein kinase and activated Nrf-2, a regulator of HO-1 gene transcription. Gallium-induced Nrf-2 activation and HO-1 expression were diminished by a p38 MAP kinase inhibitor. We conclude that gallium nitrate induces cellular oxidative stress as an early event which then triggers the expression of HO-1 and MT2A through different pathways. PMID:18586083

  11. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    KAUST Repository

    Balk, Melike

    2015-03-02

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils.

  12. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    Directory of Open Access Journals (Sweden)

    Melike eBalk

    2015-03-01

    Full Text Available Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests.The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden under the nitrate-limited conditions of most mangrove forest soils.

  13. Impact of ammonium nitrate and sodium nitrate on tadpoles of Alytes obstetricans.

    Science.gov (United States)

    Garriga, Núria; Montori, A; Llorente, G A

    2017-07-01

    The presence of pesticides, herbicides and fertilisers negatively affect aquatic communities in general, and particularly amphibians in their larval phase, even though sensitivity to pollutants is highly variable among species. The Llobregat Delta (Barcelona, Spain) has experienced a decline of amphibian populations, possibly related to the reduction in water quality due to the high levels of farming activity, but also to habitat loss and alteration. We studied the effects of increasing ammonium nitrate and sodium nitrate levels on the survival and growth rate of Alytes obstetricans tadpoles under experimental conditions. We exposed larvae to increasing concentrations of nitrate and ammonium for 14 days and then exposed them to water without pollutants for a further 14 days. Only the higher concentrations of ammonium (>33.75 mg/L) caused larval mortality. The growth rate of larvae was reduced at ≥22.5 mg/L NH 4 + , although individuals recovered and even increased their growth rate once exposure to the pollutant ended. The effect of nitrate on growth rate was detected at ≥80 mg/L concentrations, and the growth rate reduction in tadpoles was even observed during the post-exposure phase. The concentrations of ammonium with adverse effects on larvae are within the range levels found in the study area, while the nitrate concentrations with some adverse effect are close to the upper range limit of current concentrations in the study area. Therefore, only the presence of ammonium in the study area is likely to be considered of concern for the population of this species, even though the presence of nitrate could cause some sublethal effects. These negative effects could have an impact on population dynamics, which in this species is highly sensitive to larval mortality due to its small clutch size and prolonged larval period compared to other anuran amphibians.

  14. Calcium signalling: fishing out molecules of mitochondrial calcium transport.

    Science.gov (United States)

    Hajnóczky, György; Csordás, György

    2010-10-26

    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.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    BACKGROUND: Electroporation with calcium (calcium electroporation) can induce ATP depletion-associated cellular death. In the clinical setting, the cytotoxic drug bleomycin is currently used with electroporation (electrochemotherapy) for palliative treatment of tumors. Calcium electroporation off...

  16. Microwave-assisted biomimetic synthesis of hydroxyapatite using different sources of calcium.

    Science.gov (United States)

    Türk, S; Altınsoy, I; ÇelebiEfe, G; Ipek, M; Özacar, M; Bindal, C

    2017-07-01

    In this study, some properties of biomimetic synthesized hydroxyapatite by using different sources of calcium were investigated. Biomimetic synthesis of hydroxyapatite was carried out in microwave oven using 1.5 simulated body fluid (SBF) solution having different calcium sources with 800W power for 15min. As phosphorus source di-ammonium hydrogen phosphate ((NH4)2HPO4) while for each sample as a calcium sources calcium chloride (CaCl2), calcium nitrate tetra hydrate (Ca(NO3)2·4H2O) and calcium hydroxide (Ca(OH)2) were utilized, respectively. For comparison, precipitation process was also performed in only 1.5 SBF solution without calcium and phosphorus sources. The presence of phases in synthesized hydroxyapatite was confirmed by XRD. The crystallinity and crystalline size of the phases in as synthesized powders were also calculated by using XRD data. It was found that the unique phase is hydroxyapatite (HAp, Ca5(PO4)3(OH)) by using the calcium nitrate tetra hydrate and calcium hydroxide sources, while the dominant phases are tri-calcium phosphates (TCP) and HAp for CaCl2 source and 1.5SBF which does not contain any additional Ca source. SEM studies revealed that nano-hexagonal rods and nano-spherical hydroxyapatites could be synthesized by using this process. Energy-dispersive X-ray spectroscopy (EDS) analysis revealed that the Ca/P ratio near to be as 1.5 which is the value for HAp in bone. Raman and Fourier transform-infrared spectroscopy (FT-IR) results combined with the X-ray diffraction (XRD) indicates that dominantly the present of single phase is HAp. The crystal size and fraction crystallinity of as synthesized HAp powders were changed between 29.5 and 45.4nm and 0.53-2.37, respectively. Results showed that microwave assisted biomimetic synthesis is a promising method for obtaining HAp powders in shorter process time. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Using Nitrate Isotopes to Distinguish Pathways along which Unprocessed Atmospheric Nitrate is Transported through Forests to Streams

    Science.gov (United States)

    Sebestyen, S. D.

    2013-12-01

    Evaluation of natural abundance oxygen and nitrogen isotopes in nitrate has revealed that atmospheric deposition of nitrate to forests sometimes has direct effects on the timing and magnitude of stream nitrate concentrations. Large amounts of unprocessed atmospheric nitrate have sometimes been found in streams during snowmelt and stormflow events. Despite increasing evidence that unprocessed atmospheric nitrate may be transported without biological processing to streams at various times and multiple locations, little has been reported about specific hydrological processes. I synthesized research findings from a number of studies in which nitrate isotopes have been measured over the past decade. Unprocessed nitrate may predominate in surficial soil waters after rainfall and snowmelt events relative to nitrate that originated from nitrification. Although transport to deep groundwater may be important in the most nitrogen saturated catchments, the transport of unprocessed atmospheric nitrate along shallow subsurface flowpaths is likely more important in many moderately N-polluted ecosystems, which predominate in the northeastern USA where most of my study sites are located. The presence of unprocessed atmospheric nitrate in surficial soils was linked to stream nitrate concentrations when large amounts of unprocessed nitrate were occasionally routed along lateral, shallow subsurface flowpaths during stormflow events. During these events, water tables rose to saturate shallow-depth soils. When catchments were drying or dryer, atmospheric nitrate was completely consumed by biological processing as flowpaths shifted from lateral to vertical transport through soils. The source areas of unprocessed atmospheric nitrate were usually limited to soils that were adjacent to streams, with little to no near-surface saturation and transport of unprocessed nitrate from more distal hillslope positions. The occasional large amounts of unprocessed atmospheric nitrate in soil water

  18. Seasonal variations in nitrate content, total nitrogen, and nitrate reductase activities of macrophytes from a chalk stream in Upper Bavaria.

    Science.gov (United States)

    Melzer, A; Kaiser, R

    1986-07-01

    11 macrophytic species from a groundwater influenced chalk stream in Upper Bavaria were investigated during a period of one year in order to determine differences in the endogenous nitrate content, in total nitrogen content and in nitrate reductase activity (NRA). Nitrate concentrations of different plants taken from the same site of the river varied by a factor of approximately 103. A maximum of 1,958 μmol NO 3- g-1 dry w. could be measured in the petioles of Nasturtium officinale, which accounts for 12% of plant dry w. Very high values were also found in Callitriche obtusangula and Veronica angallis-aquatica. In comparison to the ambient water, mean accumulation rates of up to 131 could be found. In Fontinalis antipyretica, the plant poorest in nitrate, the ratio was only 1.24:1. Elodea canadensis belonged to a group of plants having very low nitrate concentrations. Since NRA was very low too, it is assumed that nitrogen nutrition of this species depends rather on ammonia than on nitrate. With a few exceptions nitrate content of different plant organs varied markedly. In general they were lowest in leaves and highest in shoot axes. Appreciable amounts of nitrate were also found in the roots of plants. No correlation could be found between endogenous nitrate content and NRA. In contrast to endogenous nitrate content and NRA, total nitrogen concentrations of the plants did not differ significantly.

  19. Evaluating Ecosystem Services for Reducing Groundwater Nitrate Contamination: Nitrate Attenuation in the Unsaturated and Saturated Zones

    Science.gov (United States)

    Wang, J.

    2013-12-01

    Nitrates are the most common type of groundwater contamination in agricultural regions. Environmental policies targeting nitrates have focused on input control (e.g., restricted fertilizer application), intermediate loads control (e.g., reduce nitrate leached from crop fields), and final loads control (e.g., reduce catchment nitrate loads). Nitrate loads can be affected by hydrological processes in both unsaturated and saturated zones. Although many of these processes have been extensively investigated in literature, they are commonly modeled as exogenous to farm management. A couple of recent studies by scientists from the Lawrence Livermore National Laboratory show that in some situations nitrate attenuation processes in the unsaturated/saturated zone, particularly denitrification, can be intensified by certain management practices to mitigate nitrate loads. Therefore, these nitrate attenuation processes can be regarded as a set of ecosystem services that farmers can take advantage of to reduce their cost of complying with environmental policies. In this paper, a representative California dairy farm is used as a case study to show how such ecosystem attenuation services can be framed within the farm owner's decision-making framework as an option for reducing groundwater nitrate contamination. I develop an integrated dynamic model, where the farmer maximizes discounted net farm profit over multiple periods subject to environmental regulations. The model consists of three submodels: animal-waste-crop, hydrologic, and economic model. In addition to common choice variables such as irrigation, fertilization, and waste disposal options, the farmer can also endogenously choose from three water sources: surface water, deep groundwater (old groundwater in the deep aquifer that is not affected by farm effluent in the short term), and shallow groundwater (drainage water that can be recycled via capture wells at the downstream end of the farm). The capture wells not only

  20. Calcium, vitamin D, and your bones

    Science.gov (United States)

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

  1. Calcium Supplements: Do Men Need Them Too?

    Science.gov (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 ...

  2. Sulphonamides as corrosion inhibitor: Experimental and DFT studies

    Science.gov (United States)

    Obayes, Hasan R.; Al-Amiery, Ahmed A.; Alwan, Ghadah H.; Abdullah, Thamer Adnan; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar

    2017-06-01

    Inhibitors are synthetic and natural molecules have various functional groups like double or triple bonds and heteroatoms; N, O or S, which permit adsorption onto the MS (metal surface). These inhibitors have the ability to adsorb onto the MS and block the active site that was reducing the corrosion rate. Inhibition efficiencies of the investigated compounds: Sulfacetamide (SAM), Sulfamerazine (SMR), Sulfapyridine (SPY) and Sulfathiazole (STI), as inhibitors in corrosive solution were evaluated based on weight loss technique. Nitro and Amino groups were chosen for the study of the substituted reaction of four corrosion inhibitor compounds: SAM, SMR, SPY and STI, theoretically utilizing the thickness capacities hypothesis DFT (density functions theory) method with the level [rB3LYP/6-311G(d,p)]. Our research demonstrated that the nitration of studied molecules lead to a diminishing in inhibition efficiencies, group lead to an increase in inhibition efficiency. Compared with corrosion inhibitor molecules these results gave a significant improvement in inhibition efficiency for corrosion inhibitor molecules.

  3. Effects of Staphylococcus aureus-hemolysin A on calcium signalling in immortalized human airway epithelial cells.

    Science.gov (United States)

    Eichstaedt, Stefanie; Gäbler, Karoline; Below, Sabine; Müller, Christian; Kohler, Christian; Engelmann, Susanne; Hildebrandt, Petra; Völker, Uwe; Hecker, Michael; Hildebrandt, Jan-Peter

    2009-02-01

    Part of the innate defence of bronchial epithelia against bacterial colonization is secretion of salt and water which generally depends on coordinated actions of receptor-mediated cAMP- and calcium signalling. The hypothesis that Staphylococcus aureus-virulence factors interfere with endogenous signals in host cells was tested by measuring agonist-mediated changes in [Ca(2+)](i) in S9 cells upon pre-incubation with bacterial secretory products. S9 cells responded to mAChR-activation with calcium release from intracellular stores and capacitative calcium influx. Treatment of cells with culture supernatants of S. aureus (COL) or with recombinant alpha-hemolysin (Hla) resulted in time- and concentration-dependent changes in [Ca(2+)](i). High concentrations of Hla (2000 ng/ml) resulted in elevations in [Ca(2+)](i) elicited by accelerated calcium influx. A general Hla-mediated permeabilization of S9 cell membranes to small molecules, however, did not occur. Lower concentrations of Hla (200 ng/ml) induced a reduction in [Ca(2+)](i)-levels during the sustained plateau phase of receptor-mediated calcium signalling which was abolished by pre-incubation of cells with carboxyeosin, an inhibitor of the plasma membrane calcium-ATPase. This indicates that low concentrations of Hla change calcium signalling by accelerating pump-driven extrusion of Ca(2+) ions. In vivo, such a mechanism may result in attenuation of calcium-mediated cellular defence functions and facilitation of bacterial adherence to the bronchial epithelium.

  4. Laboratory study of nitrate photolysis in Antarctic snow

    DEFF Research Database (Denmark)

    Berhanu, Tesfaye A.; Meusinger, Carl; Erbland, Joseph

    2014-01-01

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [" Laboratory study of nitrate photolysis...... in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry," J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate (15N, 17O, and 18O) provide...... additional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters...

  5. Mechanisms involved in calcium deficiency development in tomato fruit in response to gibberellins

    Science.gov (United States)

    Although gibberellins (GAs) have been shown to induce the calcium deficiency disorder, blossom-end rot (BER), development in tomato fruit (Solanum lycopersicum), the mechanisms involved remain largely unexplored. Our objectives were to better understand how GAs and a GA biosynthesis inhibitor affect...

  6. Impact of weather variability on nitrate leaching

    Science.gov (United States)

    Richards, Karl; Premrov, Alina; Hackett, Richard; Coxon, Catherine

    2016-04-01

    The loss of nitrate (NO3 - N) to water via leaching and overland flow contributes to eutrophication of freshwaters, transitional and near coastal waters with agriculture contributing significantly to nitrogen (N) loading to these water. Environmental regulations, such as the Nitrates and Water Framework Directives, have increased constraints on farmers to improve N management in regions at risk of NO3--N loss to water. In addition, farmers also have to manage their systems within a changing climate as the imapcts of climate change begin to impact resulting in more frequent extreme events such as floods and droughts. The objective of this study was to investigate the link between weather volatility and the concentration of leached NO3--N spring barley. Leaching was quantified under spring barley grown on a well-drained, gravelly sandy soil using ceramic cup samplers over 6 drainage years under the same farming practices and treatments. Soil solution NO3--N concentrations under spring barley grown by conventional inversion ploughing and reduced tillage were compared to weather parameters over the period. Weather was recorded at a national Met Eireann weather station on site. Soil solution NO3--N varied significantly between years. Within individual years NO3--N concentrations varied over the drainage season, with peak concentrations generally observed in the autumn time, decreasing thereafter. Under both treatments there was a three-fold difference in mean annual soil solution NO3--N concentration over the 6 years with no change in the agronomic practices (crop type, tillage type and fertiliser input). Soil solution nitrate concentrations were significantly influenced by weather parameters such as rainfall, effective drainage and soil moisture deficit. The impact of climate change in Ireland could lead to increased NO3--N loss to water further exacerbating eutrophication of sensitive estuaries. The increased impact on eutrophication of waters, related to climatic

  7. Calcium dobesilate in the treatment of diabetic retinopathy.

    Science.gov (United States)

    Garay, Ricardo P; Hannaert, Patrick; Chiavaroli, Carlo

    2005-01-01

    The incidence of diabetic retinopathy is still increasing in developed countries. Tight glycemic control and laser therapy reduce vision loss and blindness, but do not reverse existing ocular damage and only slow the progression of the disease. New pharmacologic agents that are currently under development and are specifically directed against clearly defined biochemical targets (i.e. aldose reductase inhibitors and protein kinase C-beta inhibitors) have failed to demonstrate significant efficacy in the treatment of diabetic retinopathy in clinical trials. In contrast, calcium dobesilate (2,5-dihydroxybenzenesulfonate), which was discovered more than 40 years ago and is registered for the treatment of diabetic retinopathy in more than 20 countries remains, to our knowledge, the only angioprotective agent that reduces the progression of this disease. An overall review of published studies involving calcium dobesilate (CLS 2210) depicts a rather 'non-specific' compound acting moderately, but significantly, on the various and complex disorders that contribute to diabetic retinopathy. Recent studies have shown that calcium dobesilate is a potent antioxidant, particularly against the highly damaging hydroxyl radical. In addition, it improves diabetic endothelial dysfunction, reduces apoptosis, and slows vascular cell proliferation.

  8. Stable prenucleation calcium carbonate clusters.

    Science.gov (United States)

    Gebauer, Denis; Völkel, Antje; Cölfen, Helmut

    2008-12-19

    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.

  9. 4-[(2-Hydroxybenzylamino]pyridinium nitrate

    Directory of Open Access Journals (Sweden)

    Shan Gao

    2012-08-01

    Full Text Available The planes of the aromatic rings in the cation of the title salt, C12H13N2O+·NO3−, are twisted along the –CH2—NH– single bond by 75.3 (1°. In the crystal, the phenol O, amine N and pyridinium N atoms are hydrogen-bond donors to the O atoms of the nitrate counter-ions. These hydrogen bonds lead to the formation of a layer in the crystal.

  10. Difficulties in the Nitrates Directive Implementation in Romania

    OpenAIRE

    MIHĂIESCU Tania; R. MIHĂIESCU; Antonia ODAGIU

    2010-01-01

    The EU Nitrates Directive (Council Directive 91/676/EEC) forms an integrate part of the Water FrameworkDirective and is one of the key instruments in the protection of waters against agricultural pressures [6]. The NitratesDirective aims to protect water quality across Europe by reducing water pollution caused or induced by nitrates fromagricultural sources and by promoting the use of good agricultural practices. Implementation of this directive hasproved to be a major challenge for Member St...

  11. Implementation of the eu nitrates directive in Turkey

    OpenAIRE

    BİLGİN YILDIRIM, Hatice; DEMİR, Süleyman

    2012-01-01

    The EU Nitrates Directive is of a prime importance in respect of sustaining the natural resources for the reduction and prevention of nitrate pollution resulting from agricultural activities, and it constitutes an integral part of the EU Water Framework Directive. Accepted by the European Council in 1991, the directive entered into force being published in Official Gazette in 2004 in Turkey as “Regulation on the Protection of Waters against Pollution Caused by Nitrates from Agricultural Sourc...

  12. Micromachined Amperometric Nitrate Sensor with an Anion Permeable Membrane

    OpenAIRE

    Kim, Dohyun; Goldberg, Ira; Judy, J W

    2004-01-01

    A nitrate-sensing system that consists of a micromachined sensor substrate, anion-permeable membrane, integrated microfluidic channels, and standard fluidic connectors has been designed, fabricated, assembled, and tested. Our microsensor was designed for in-situ monitoring of nitrate concentrations in ground water. A silver electrode was patterned for amperometric nitrate detection. An electrochemically oxidized silver electrode was used as a reference electrode. Microfluidic channels were fa...

  13. Immobilization of nitrate reductase onto epoxy affixed silver nanoparticles for determination of soil nitrates.

    Science.gov (United States)

    Sachdeva, Veena; Hooda, Vinita

    2015-08-01

    Epoxy glued silver nanoparticles were used as immobilization support for nitrate reductase (NR). The resulting epoxy/AgNPs/NR conjugates were characterized at successive stages of fabrication by scanning electron microscopy and fourier transform infrared spectroscopy. The immobilized enzyme system exhibited reasonably high conjugation yield (37.6±0.01 μg/cm(2)), with 93.54±0.88% retention of specific activity. Most favorable working conditions of pH, temperature and substrate concentration were ascertained to optimize the performance of epoxy/AgNPs/NR conjugates for soil nitrate quantification. The analytical results for soil nitrate determination were consistent, reliable and reproducible. Minimum detection limit of the method was 0.05 mM with linearity from 0.1 to 11.0 mM. The % recoveries of added nitrates (0.1 and 0.2 mM) wereEpoxy/AgNPs bound NR had a half-life of 18 days at 4 °C and retained 50% activity after 15 reuses. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Aluminum nitrate recrystallization and recovery from liquid extraction raffinates

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, W.L.; Compere, A.L.; Googin, J.M.; Huxtable, W.P.

    1991-09-01

    The solid sludges resulting form biodenitrification of discarded aluminum nitrate are the largest Y-12 Plant process solid waste. Aluminum nitrate feedstocks also represent a major plant materials cost. The chemical constraints on aluminum nitrate recycle were investigated to determine the feasibility of increasing recycle while maintaining acceptable aluminum nitrate purity. Reported phase behavior of analogous systems, together with bench research, indicated that it would be possible to raise the recycle rate from 35% to between 70 and 90% by successive concentration and recrystallization of the mother liquor. A full scale pilot test successfully confirmed the ability to obtain 70% recycle in existing process equipment.

  15. Oxygen exchange between nitrate molecules during nitrite oxidation by Nitrobacter.

    Science.gov (United States)

    DiSpirito, A A; Hooper, A B

    1986-08-15

    During oxidation of nitrite, cells of Nitrobacter winogradskyi are shown to catalyze the active exchange of oxygen atoms between exogenous nitrate molecules (production of 15N16/18O3- during incubation of 14N16/18O3-, 15N16O3-, and 15N16O2- in H216O). Little, if any, exchange of oxygens between nitrate and water also occurs (production of 15N16/18O3- during incubation of 15N16O3- and 14N16O2- in H218O). 15N species of nitrate were assayed by 18O-isotope shift in 15N NMR. Taking into account the O-exchange reactions which occur during nitrite oxidation, H2O is seen to be the source of O in nitrate produced by oxidation of nitrite by N. winogradskyi. The data do not establish whether the nitrate-nitrate O exchange is catalyzed by nitrite oxidase (H2O + HNO2----HNO3 + 2H+ + 2e-) or nitrate reductase (HNO3 + 2H+ + 2e-----HNO2 + H2O) or both enzymes in consort. The nitrate-nitrate exchange reaction suggests the existence of an oxygen derivative of a H2O-utilizing oxidoreductase.

  16. Significant accumulation of nitrate in Chinese semi-humid croplands

    Science.gov (United States)

    Zhou, Junyu; Gu, Baojing; Schlesinger, William H.; Ju, Xiaotang

    2016-04-01

    Soil nitrate is important for crop growth, but it can also leach to groundwater causing nitrate contamination, a threat to human health. Here, we report a significant accumulation of soil nitrate in Chinese semi-humid croplands based upon more than 7000 samples from 141 sites collected from 1994 to 2015. In the 0-4 meters depth of soil, total nitrate accumulation reaches 453 ± 39, 749 ± 75, 1191 ± 89, 1269 ± 114, 2155 ± 330 kg N ha-1 on average in wheat, maize, open-field vegetables (OFV), solar plastic-roofed greenhouse vegetables (GHV) and orchard fields, respectively. Surprisingly, there is also a comparable amount of nitrate accumulated in the vadose-zone deeper than 4 meters. Over-use of N fertilizer (and/or manure) and a declining groundwater table are the major causes for this huge nitrate reservoir in the vadose-zone of semi-humid croplands, where the nitrate cannot be denitrified due to the presence of oxygen and lack of carbon sources. Future climatic change with more extreme rainfall events would increase the risk of accumulated nitrate moving downwards and threatening groundwater nitrate contamination.

  17. Is nitrate an endocrine active compound in fish?

    DEFF Research Database (Denmark)

    Mose, M. P.; Kinnberg, Karin Lund; Bjerregaard, Poul

    were exposed to nitrate and nitrite from hatch to sexual maturation (60 d) and sex ratio and vitellogenin concentrations were determined. Juvenile brown trout were exposed in a short-term experiment and the concentrations of vitellogenin were determined. The sex ratio in zebrafish was not affected......Nitrate and nitrite taken up into fish may be reduced to NO which is known to be a signalling compound in the organism contributing to the regulation of i.e. steroid synthesis. Exposure of male rats to nitrate and nitrite results in reduced plasma concentrations of testosterone (also nitrate...

  18. NITRATE REDUCTASE ACTIVITY DURING HEAT SHOCK IN WINTER WHEAT

    Directory of Open Access Journals (Sweden)

    Klimenko S.B.

    2006-03-01

    Full Text Available Nitrates are the basic source of nitrogen for the majority of plants. Absorption and transformation of nitrates in plants are determined by external conditions and, first of all, temperature and light intensity. The influence of the temperature increasing till +40 0С on activity of nitrate reductase was studied. It is shown, that the rise of temperature was accompanied by sharp decrease of activity nitrate reductase in leaves of winter wheat, what, apparently, occurred for the account deactivations of enzyme and due to its dissociation.

  19. DPP-4 inhibitors

    DEFF Research Database (Denmark)

    Deacon, Carolyn F.

    2016-01-01

    Dipeptidyl peptidase (DPP)-4 inhibitors inhibit the activity of the enzyme responsible for the initial rapid degradation of the incretin hormones, thereby enhancing their antihyperglycemic effects.......Dipeptidyl peptidase (DPP)-4 inhibitors inhibit the activity of the enzyme responsible for the initial rapid degradation of the incretin hormones, thereby enhancing their antihyperglycemic effects....

  20. Vascular calcification: Inducers and inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Donghyun, E-mail: dhlee@cau.ac.kr [Department of Biomedical Engineering, Division of Integrative Engineering, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul 156-756 (Korea, Republic of)

    2011-09-15

    Highlights: {center_dot} Types of vascular calcification processes. {center_dot} Inducers of vascular calcification. {center_dot} Inhibitors of vascular calcifications. {center_dot} Clinical utility for vascular calcification therapy. {center_dot} Implications for the development of new tissue engineering strategies. - Abstract: Unlike the traditional beliefs, there are mounting evidences suggesting that ectopic mineral depositions, including vascular calcification are mostly active processes, many times resembling that of the bone mineralization. Numbers of agents are involved in the differentiation of certain subpopulation of smooth muscle cells (SMCs) into the osteoblast-like entity, and the activation and initiation of extracellular matrix ossification process. On the other hand, there are factors as well, that prevent such differentiation and ectopic calcium phosphate formation. In normal physiological environments, activities of such procalcific and anticalcific regulatory factors are in harmony, prohibiting abnormal calcification from occurring. However, in certain pathophysiological conditions, such as atherosclerosis, chronic kidney disease (CKD), and diabetes, such balances are altered, resulting in abnormal ectopic mineral deposition. Understanding the factors that regulate the formation and inhibition of ectopic mineral formation would be beneficial in the development of tissue engineering strategies for prevention and/or treatment of such soft-tissue calcification. Current review focuses on the factors that seem to be clinically relevant and/or could be useful in developing future tissue regeneration strategies. Clinical utilities and implications of such factors are also discussed.

  1. Does the evidence about health risks associated with nitrate ingestion warrant an increase of the nitrate standard for drinking water?

    Directory of Open Access Journals (Sweden)

    Benjamin Nigel

    2006-09-01

    Full Text Available Abstract Several authors have suggested that it is safe to raise the health standard for nitrate in drinking water, and save money on measures associated with nitrate pollution of drinking water resources. The major argument has been that the epidemiologic evidence for acute and chronic health effects related to drinking water nitrate at concentrations near the health standard is inconclusive. With respect to the chronic effects, the argument was motivated by the absence of evidence for adverse health effects related to ingestion of nitrate from dietary sources. An interdisciplinary discussion of these arguments led to three important observations. First, there have been only a few well-designed epidemiologic studies that evaluated ingestion of nitrate in drinking water and risk of specific cancers or adverse reproductive outcomes among potentially susceptible subgroups likely to have elevated endogenous nitrosation. Positive associations have been observed for some but not all health outcomes evaluated. Second, the epidemiologic studies of cancer do not support an association between ingestion of dietary nitrate (vegetables and an increased risk of cancer, because intake of dietary nitrate is associated with intake of antioxidants and other beneficial phytochemicals. Third, 2–3 % of the population in Western Europe and the US could be exposed to nitrate levels in drinking water exceeding the WHO standard of 50 mg/l nitrate, particularly those living in rural areas. The health losses due to this exposure cannot be estimated. Therefore, we conclude that it is not possible to weigh the costs and benefits from changing the nitrate standard for drinking water and groundwater resources by considering the potential consequences for human health and by considering the potential savings due to reduced costs for nitrate removal and prevention of nitrate pollution.

  2. Regulation of transcript level and synthesis of nitrate reductase by phytochrome and nitrate in turions of Spirodela polyrhiza (L.) Schleiden.

    Science.gov (United States)

    Appenroth, K J; Oelmüller, R; Schuster, C; Mohr, H

    1992-11-01

    Control by light and nitrate of the appearance of nitrate reductase (NR; EC 1.6.6.1) in the turions of Spirodela polyrhiza (L.) Schieiden was investigated during the pre-germination phase, i.e. up to 120 h after the transfer from after-ripening to germination conditions. Turions are particularily suited for this type of coaction study since control of nitrate uptake by light and long-distance transport of nitrate do not play a role. Control of NR gene expression was mainly studied between 72 and 120 h after transfer to germination conditions (phase II of the pre-germination process). It was found that the effect of light on NR appearance is exerted via phytochrome. The light effect on enzyme synthesis was only observed in the presence of nitrate. On the other hand, in darkness, the NR level decreased to almost zero even in the presence of an optimum supply of nitrate. It is concluded that in phase II a coaction of light (phytochrome) and nitrate is required to bring about NR synthesis. However, when nitrate was applied to turions - following a dark incubation without nitrate - the turions responded to nitrate even in darkness with strong NR synthesis. This response was augmented by light. The highest transcript levels were observed in the presence of both factors, light and nitrate. As a single factor, light was more effective in stimulating the transcript level than nitrate. However, no correlation between the transcript level and the rate of enzyme synthesis was observed. This is consistent with the previous conclusion (Schuster et al. 1988, Planta 174, 426-432) that in higher plants control at the transcript level is only coarse and does not determine quantitatively the output at the level of enzyme protein.

  3. Nitrate radicals and biogenic volatile organic compounds ...

    Science.gov (United States)

    Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO3) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO3-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number of important uncertainties remain. These include an incomplete understanding of the rates, mechanisms, and organic aerosol yields for NO3-BVOC reactions, lack of constraints on the role of heterogeneous oxidative processes associated with the NO3 radical, the difficulty of characterizing the spatial distributions of BVOC and NO3 within the poorly mixed nocturnal atmosphere, and the challenge of constructing appropriate boundary layer schemes and non-photochemical mechanisms for use in state-of-the-art chemical transport and chemistry–climate models. This review is the result of a workshop of the same title held at the Georgia Institute of Technology in June 2015. The first half of the review summarizes the current literature on NO3-BVOC chemistry, with a particular focus on recent advances in

  4. Chlorination and nitration of soy isoflavones.

    Science.gov (United States)

    Boersma, B J; Patel, R P; Kirk, M; Jackson, P L; Muccio, D; Darley-Usmar, V M; Barnes, S

    1999-08-15

    Diets enriched in soy foods containing a high concentration of isoflavonoids are associated with a decrease in the incidence of several chronic inflammatory diseases. Studies with experimental models of diseases, such as atherosclerosis, suggest that these effects can be ascribed to the biological properties of the isoflavones. Since the isoflavones and tyrosine have structural similarities and modifications to tyrosine by inflammatory oxidants such as hypochlorous acid (HOCl) and peroxynitrite (ONOO(-)) have been recently recognized, we hypothesized that the isoflavones also react with HOCl and ONOO(-). Using an in vitro approach, we demonstrate in the present study that the isoflavones genistein, daidzein, and biochanin-A can be chlorinated and nitrated by these oxidants. These reactions were investigated using high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance. In the reaction with HOCl, both mono- and dichlorinated derivatives of genistein and biochanin-A are formed, whereas with daidzein only a monochlorinated derivative was detected. The reaction between genistein or daidzein and ONOO(-) yielded a mononitrated product. However, no nitrated product was detected with biochanin-A. Furthermore, the reaction between genistein and sodium nitrite and HOCl yielded a chloronitrogenistein derivative, as well as a dichloronitrogenistein derivative. These results indicate that the ability of the isoflavones to react with these oxidant species depends on their structure and suggest that they could be formed under conditions where these reactive species are generated under pathological conditions. Copyright 1999 Academic Press.

  5. Factors influencing the crystallisation of calcium oxalate in urine - critique

    Science.gov (United States)

    Robertson, W. G.; Scurr, D. S.; Bridge, Christine M.

    1981-05-01

    This article describes in vivo and in vitro studies carried out to determine the factors which influence the nucleation, crystal growth and crystal aggregation of calcium oxalate in urine. It covers the roles of urinary supersaturation, the oxalate/calcium ratio of urine, the relative importance of hyperoxaluria and hypercalciuria in causing crystalluria and the importance of crystalluria in the genesis of calcium oxalate stones. In vitro studies on seeded crystal growth and aggregation and on the spontaneous precipitation of calcium oxalate define some of the macromolecular factors in urine which promote and inhibit crystal growth and aggregation. Fractionation of the urinary macromolecular anions shows that the major inhibitors are in the acidic glycosaminoglycan fraction with relatively minor contributions from Tamm-Horsfall mucoprotein and from RNA. One insoluble residue acts as a weak promoter of growth and aggregation but when re-combined with the inhibitory fractions the promoter effect is cancelled out. The net effect of urine is to inhibit strongly growth and aggregation.

  6. Amorphous Calcium Carbonate Based-Microparticles for Peptide Pulmonary Delivery.

    Science.gov (United States)

    Tewes, Frederic; Gobbo, Oliviero L; Ehrhardt, Carsten; Healy, Anne Marie

    2016-01-20

    Amorphous calcium carbonate (ACC) is known to interact with proteins, for example, in biogenic ACC, to form stable amorphous phases. The control of amorphous/crystalline and inorganic/organic ratios in inhalable calcium carbonate microparticles may enable particle properties to be adapted to suit the requirements of dry powders for pulmonary delivery by oral inhalation. For example, an amorphous phase can immobilize and stabilize polypeptides in their native structure and amorphous and crystalline phases have different mechanical properties. Therefore, inhalable composite microparticles made of inorganic (i.e., calcium carbonate and calcium formate) and organic (i.e., hyaluronan (HA)) amorphous and crystalline phases were investigated for peptide and protein pulmonary aerosol delivery. The crystalline/amorphous ratio and polymorphic form of the inorganic component was altered by changing the microparticle drying rate and by changing the ammonium carbonate and HA initial concentration. The bioactivity of the model peptide, salmon calcitonin (sCT), coprocessed with alpha-1-antitrypsin (AAT), a model protein with peptidase inhibitor activity, was maintained during processing and the microparticles had excellent aerodynamic properties, making them suitable for pulmonary aerosol delivery. The bioavailability of sCT after aerosol delivery as sCT and AAT-loaded composite microparticles to rats was 4-times higher than that of sCT solution.

  7. Calcium-regulated import of myosin IC into the nucleus.

    Science.gov (United States)

    Maly, Ivan V; Hofmann, Wilma A

    2016-06-01

    Myosin IC is a molecular motor involved in intracellular transport, cell motility, and transcription. Its mechanical properties are regulated by calcium via calmodulin binding, and its functions in the nucleus depend on import from the cytoplasm. The import has recently been shown to be mediated by the nuclear localization signal located within the calmodulin-binding domain. In the present paper, it is demonstrated that mutations in the calmodulin-binding sequence shift the intracellular distribution of myosin IC to the nucleus. The redistribution is displayed by isoform B, described originally as the "nuclear myosin," but is particularly pronounced with isoform C, the normally cytoplasmic isoform. Furthermore, experimental elevation of the intracellular calcium concentration induces a rapid import of myosin into the nucleus. The import is blocked by the importin β inhibitor importazole. These findings are consistent with a mechanism whereby calmodulin binding prevents recognition of the nuclear localization sequence by importin β, and the steric inhibition of import is released by cell signaling leading to the intracellular calcium elevation. The results establish a mechanistic connection between the calcium regulation of the motor function of myosin IC in the cytoplasm and the induction of its import into the nucleus. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Atomic structure of intracellular amorphous calcium phosphate deposits.

    Science.gov (United States)

    Betts, F; Blumenthal, N C; Posner, A S; Becker, G L; Lehninger, A L

    1975-01-01

    The radial distribution function calculated from x-ray diffraction of mineralized cytoplasmic structures isolated from the hepatopancreas of the blue crab (Callinectes sapidus) is very similar to that previously found for synthetic amorphous calcium phosphate. Both types of mineral apparently have only short-range atomic order, represented as a neutral ion cluster of about 10 A in longest dimension, whose probable composition is expressed by the formula Ca9(PO4)6. The minor differences observed are attributed to the presence in the biological mineral of significant amounts of Mg-2+ and ATP. Synthetic amorphous calcium phosphate in contact with a solution containing an amount of ATP equivalent to that of the biological mineral failed to undergo conversion to the thermodynamically more stable hydroxyapatite. The amorphous calcium phosphate of the cytoplasmic mineral granules is similarly stable, and does not undergo conversion to hydroxyapatite, presumably owing to the presence of ATP and Mg-2+, known in inhibitors of the conversion process. The physiological implications of mineral deposits consisting of stabilized calcium phosphate ion clusters are discussed. PMID:1056015

  9. Assessing the Role of Sewers and Atmospheric Deposition as Nitrate Contamination Sources to Urban Surface Waters using Stable Nitrate Isotopes

    Science.gov (United States)

    Sikora, M. T.; Elliott, E. M.

    2009-12-01

    Excess nitrate (NO3-) contributes to the overall degraded quality of streams in many urban areas. These systems are often dominated by impervious surfaces and storm sewers that can route atmospherically deposited nitrogen, from both wet and dry deposition, to waterways. Moreover, in densely populated watersheds there is the potential for interaction between urban waterways and sewer systems. The affects of accumulated nitrate in riverine and estuary systems include low dissolved oxygen, loss of species diversity, increased mortality of aquatic species, and general eutrophication of the waterbody. However, the dynamics of nitrate pollution from each source and it’s affect on urban waterways is poorly constrained. The isotopes of nitrogen and oxygen in nitrate have been proven effective in helping to distinguish contamination sources to ground and surface waters. In order to improve our understanding of urban nitrate pollution sources and dynamics, we examined nitrate isotopes (δ15N and δ18O) in base- and stormflow samples collected over a two-year period from a restored urban stream in Pittsburgh, Pennsylvania (USA). Nine Mile Run drains a 1,600 hectare urban watershed characterized by 38% impervious surface cover. Prior work has documented high nitrate export from the watershed (~19 kg NO3- ha-1 yr-1). Potential nitrate sources to the watershed include observed sewer overflows draining directly to the stream, as well as atmospheric deposition (~23 kg NO3- ha-1 yr-1). In this and other urban systems with high percentages of impervious surfaces, there is likely minimal input from nitrate derived from soil or fertilizer. In this presentation, we examine spatial and temporal patterns in nitrate isotopic composition collected at five locations along Nine Mile Run characterized by both sanitary and combined-sewer cross-connections. Preliminary isotopic analysis of low-flow winter streamwater samples suggest nitrate export from Nine Mile Run is primarily influenced by

  10. Difference between Burley Tobacco and Flue-Cured Tobacco in Nitrate Accumulation and Chemical Regulation of Nitrate and TSNA Contents

    Directory of Open Access Journals (Sweden)

    Yafei Li

    2017-01-01

    Full Text Available Tobacco-specific nitrosamines (TSNAs are harmful carcinogens, with nitrate as a precursor of their formation. Nitrate content is considerably higher in burley tobacco than in flue-cured tobacco, but little has been reported on the differences between types of nitrate accumulation during development. We explored nitrate accumulation prior to harvest and examined the effects of regulatory substances aimed at decreasing nitrate and TSNA accumulation. In growth experiments, nitrate accumulation in burley and flue-cured tobacco initially increased but then declined with the highest nitrate content observed during a fast-growth period. When treating tobacco crops with molybdenum (Mo during fast growth, nitrate reductase activity in burley tobacco increased significantly, but the NO3-N content decreased. These treatments also yielded significant reductions in NO3-N and TSNA contents. Therefore, we suggest that treatment with Mo during the fast-growth period and a Mo-Gfo (Mo-glufosinate combination at the maturity stage is an effective strategy for decreasing nitrate and TSNAs during cultivation.

  11. Effect of Sodium Nitrate and Nitrate Reducing Bacteria on Methane Production and Fermentation with Buffalo Rumen Liquor

    OpenAIRE

    Pillanatham Civalingam Sakthivel; Devki Nandan Kamra; Neeta Agarwal; Lal Chandra Chaudhary

    2012-01-01

    Nitrate can serve as a terminal electron acceptor in place of carbon dioxide and inhibit methane emission in the rumen and nitrate reducing bacteria might help enhance the reduction of nitrate/nitrite, which depends on the type of feed offered to animals. In this study the effects of three levels of sodium nitrate (0, 5, 10 mM) on fermentation of three diets varying in their wheat straw to concentrate ratio (700:300, low concentrate, LC; 500:500, medium concentrate, MC and 300:700, high conce...

  12. Calcium metabolism & hypercalcemia in adults.

    Science.gov (United States)

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

    2011-01-01

    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.

  13. Nitrate leaching from short-hydroperiod floodplain soils

    Science.gov (United States)

    Huber, B.; Luster, J.; Bernasconi, S. M.; Shrestha, J.; Graf Pannatier, E.

    2012-11-01

    Numerous studies have shown the importance of riparian zones to reduce nitrate (NO3-) contamination coming from adjacent agricultural land. Much less is known about nitrogen (N) transformations and nitrate fluxes in riparian soils with short hydroperiods (1-3 days of inundation) and there is no study that could show whether these soils are a N sink or source. Within a restored section of the Thur River in NE Switzerland, we measured nitrate concentrations in soil solutions as an indicator of the net nitrate production. Samples were collected along a quasi-successional gradient from frequently inundated gravel bars to an alluvial forest, at three different depths (10, 50 and 100 cm) over a one-year period. Along this gradient we quantified N input (atmospheric deposition and sedimentation) and N output (leaching) to create a nitrogen balance and assess the risk of nitrate leaching from the unsaturated soil to the groundwater. Overall, the main factor explaining the differences in nitrate concentrations was the field capacity (FC). In subsoils with high FCs and VWC near FC, high nitrate concentrations were observed, often exceeding the Swiss and EU groundwater quality criterions of 400 and 800 μmol L-1, respectively. High sedimentation rates of river-derived nitrogen led to apparent N retention up to 200 kg N ha-1 yr-1 in the frequently inundated zones. By contrast, in the mature alluvial forest, nitrate leaching exceeded total N input most of the time. As a result of the large soil N pools, high amounts of nitrate were produced by nitrification and up to 94 kg N-NO3- ha-1 yr-1 were leached into the groundwater. Thus, during flooding when water fluxes are high, nitrate from soils can contribute up to 11% to the total nitrate load in groundwater.

  14. Coupled jump rotational dynamics in aqueous nitrate solutions.

    Science.gov (United States)

    Banerjee, Puja; Yashonath, Subramanian; Bagchi, Biman

    2016-12-21

    A nitrate ion (NO3-) with its trigonal planar geometry and charges distributed among nitrogen and oxygen atoms can couple to the extensive hydrogen bond network of water to give rise to unique dynamical characteristics. We carry out detailed atomistic simulations and theoretical analyses to investigate these aspects and report certain interesting findings. We find that the nitrate ions in aqueous potassium nitrate solution exhibit large amplitude rotational jump motions that are coupled to the hydrogen bond rearrangement dynamics of the surrounding water molecules. The jump motion of nitrate ions bears certain similarities to the Laage-Hynes mechanism of rotational jump motions of tagged water molecules in neat liquid water. We perform a detailed atomic-level investigation of hydrogen bond rearrangement dynamics of water in aqueous KNO3 solution to unearth two distinct mechanisms of hydrogen bond exchange that are instrumental to promote these jump motions of nitrate ions. As observed in an earlier study by Xie et al., in the first mechanism, after breaking a hydrogen bond with nitrate ion, water forms a new hydrogen bond with a water molecule, whereas the second mechanism involves just a switching of hydrogen bond between the two oxygen atoms of the same nitrate ion (W. J. Xie et al., J. Chem. Phys. 143, 224504 (2015)). The magnitude as well as nature of the reorientational jump of nitrate ion for the two mechanisms is different. In the first mechanism, nitrate ion predominantly undergoes out-of-plane rotation, while in the second mechanism, in-plane reorientation of NO3- is favourable. These have been deduced by computing the torque on the nitrate ion during the hydrogen bond switching event. We have defined and computed the time correlation function for coupled reorientational jump of nitrate and water and obtained the associated relaxation time which is also different for the two mechanisms. These results provide insight into the relation between the coupled

  15. Dietary nitrate and blood pressure: evolution of a new nutrient?

    Science.gov (United States)

    Ashworth, Ann; Bescos, Raul

    2017-05-17

    Dietary nitrate is mainly obtained from vegetables, especially green leafy vegetables and beetroot. As a result of early research, dietary nitrate is currently viewed as a contaminant linked to increased risks of stomach cancer and methaemoglobinaemia. Consequently, nitrate levels are restricted in certain vegetables and in water supplies to ensure exposure levels remain below an acceptable daily intake of 3·7 mg/kg per d. The average nitrate intake in the UK is approximately 70 mg/d, although some population groups, such as vegetarians, may consume three times that amount. However, recent studies in the last decade suggest that dietary nitrate can significantly reduce systolic blood pressure via the nitrate-nitrite-NO pathway. A small, downward shift in systolic blood pressure across the population could significantly reduce the incidence of hypertension and mortality from CVD such as stroke. Interestingly, vegetarians tend to have lower levels of blood pressure than omnivores and epidemiological studies suggest that vegetarians have lower risks of CVD. Recent evidence is mainly focused on the acute effects of dietary nitrate supplementation and there is a lack of data looking at the chronic effects of high nitrate consumption in humans. Nevertheless, due to potential health benefits, some authors are recommending that nitrate should be considered as a nutrient necessary for health, rather than as a contaminant which needs to be restricted. This review will discuss the emerging role of dietary nitrate in the control of blood pressure and whether there is sufficient evidence to state that nitrate is a 'new' nutrient.

  16. Calcium and Calcium Supplements: Achieving the Right Balance

    Science.gov (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. http://www.uptodate.com/home/index. ...

  17. Calcium-antagonist effects of quercetin on aortic smooth muscle.

    Science.gov (United States)

    Morales, M A; Lozoya, X

    1994-08-01

    Relaxation induced by quercetin was studied on aortic rings depolarized with KCl and on Ca2+ dependent aortic contraction. Quercetin's actions as a cyclooxygenase inhibitor were compared with those of indomethacin. To determine the possible effects of quercetin on internal Ca2+ mobilization, it was assayed on aortic muscle contracted with caffeine. Quercetin relaxes aortic smooth muscle contracted with KCl (RC50 = 1.8 x 10(-4) M) and induces a rightward displacement of Ca2+ curves. The relaxation induced by quercetin is higher than that produced by indomethacin, suggesting that its action is independent of cyclooxygenase inhibition. Caffeine-induced aortic contraction was not modified by quercetin, suggesting that its effect should not involve internal calcium modulation. Our results further support the thesis that the spasmolytic action of quercetin arises from its negative modulation of calcium entry to the smooth muscle.

  18. A calcium-dependent ergosterol mutant of Saccharomyces cerevisiae.

    Science.gov (United States)

    Crowley, J H; Tove, S; Parks, L W

    1998-08-01

    ERG24 is the structural gene for the C14-sterol reductase in yeast. A lack of activity in that enzyme, mediated either by the morpholine fungicides or the insertional inactivation of ERG24, causes the accumulation of the aberrant sterol ignosterol. Cells producing this sterol are unable to grow aerobically in the routine laboratory medium, YPD. However, growth does occur on a synthetic defined medium. A novel calcium-dependent phenotype associated with alterations in the ergosterol biosynthetic pathway in yeast is described. In addition, reduction of yeast growth with an azole inhibitor of the C-14 sterol de-methylase was also modulated by an excess of calcium ions in the culture medium. These results define a new effect of ergosterol deficiency and provide important practical implications for utilizing morpholine and azole sterol biosynthetic-inhibiting fungicides.

  19. Calcium carbonate and calcium sulfate in Martian meteorite EETA79001

    Science.gov (United States)

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

    1987-01-01

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

  20. Gastric S-nitrosothiol formation drives the antihypertensive effects of oral sodium nitrite and nitrate in a rat model of renovascular hypertension.

    Science.gov (United States)

    Pinheiro, Lucas C; Amaral, Jefferson H; Ferreira, Graziele C; Portella, Rafael L; Ceron, Carla S; Montenegro, Marcelo F; Toledo, Jose Carlos; Tanus-Santos, Jose E

    2015-10-01

    Many effects of nitrite and nitrate are attributed to increased circulating concentrations of nitrite, ultimately converted into nitric oxide (NO(•)) in the circulation or in tissues by mechanisms associated with nitrite reductase activity. However, nitrite generates NO(•) , nitrous anhydride, and other nitrosating species at low pH, and these reactions promote S-nitrosothiol formation when nitrites are in the stomach. We hypothesized that the antihypertensive effects of orally administered nitrite or nitrate involve the formation of S-nitrosothiols, and that those effects depend on gastric pH. The chronic effects of oral nitrite or nitrate were studied in two-kidney, one-clip (2K1C) hypertensive rats treated with omeprazole (or vehicle). Oral nitrite lowered blood pressure and increased plasma S-nitrosothiol concentrations independently of circulating nitrite levels. Increasing gastric pH with omeprazole did not affect the increases in plasma nitrite and nitrate levels found after treatment with nitrite. However, treatment with omeprazole severely attenuated the increases in plasma S-nitrosothiol concentrations and completely blunted the antihypertensive effects of nitrite. Confirming these findings, very similar results were found with oral nitrate. To further confirm the role of gastric S-nitrosothiol formation, we studied the effects of oral nitrite in hypertensive rats treated with the glutathione synthase inhibitor buthionine sulfoximine (BSO) to induce partial thiol depletion. BSO treatment attenuated the increases in S-nitrosothiol concentrations and antihypertensive effects of oral nitrite. These data show that gastric S-nitrosothiol formation drives the antihypertensive effects of oral nitrite or nitrate and has major implications, particularly to patients taking proton pump inhibitors. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Phorbol ester stimulates calcium sequestration in saponized human platelets

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K.; Nachmias, V.T.

    1987-11-25

    When platelets are activated by agonists, calcium (Ca2+) is released from an intracellular storage site. Recent studies using fura-2 show that, after thrombin stimulation, the rise in free calcium is transient and returns to base-line levels in 2-3 min, while the transient following ADP stimulation lasts only 15-20 s. We reported previously that the phorbol ester 12,13-phorbol myristate acetate (PMA), added at nanomolar levels after thrombin, immediately accelerated the rate of return of calcium to the base line severalfold. In the present study, we used both intact and saponized platelets to determine whether this is due to stimulation of calcium sequestration. Using fura-2 and intact platelets, we found 1) that PMA stimulated the restoration of free Ca2+ levels after ADP as well as after thrombin, and 2) that H-7, an inhibitor of protein kinase C (Ca2+/phospholipid-dependent enzyme), slowed the return of Ca2+ to baseline levels. Using saponized platelets, we also found 3) that pretreatment of platelets with PMA before saponin treatment increased the ATP-dependent /sup 45/Ca2+ uptake 2-fold, with a half-maximal effect at 5 nm; 4) that most of the Ca2+ released by ionomycin or by myoinositol 1,4,5-trisphosphate; and 5) that a GTP-binding protein inhibitor, guanosine 5'-O-(2-thiodiphosphate), decreased basal or PMA-stimulated /sup 45/Ca2+ uptake in saponin-treated platelets. Our data suggest that activation of protein kinase C stimulates the sequestration of Ca2+ independently of cAMP or myoinositol 1,4,5-trisphosphate.

  2. Regioselective nitration of aromatic substrates in zeolite cages

    Indian Academy of Sciences (India)

    Unknown

    (wherein polynitration is a serious handicap to selective nitration) in zeolite environment is not explored. With these goals in mind, we have reported17 recently regioselective nitration of phenol inside the cages/channels of zeolite media using fuming nitric acid. In our attempts to delineate the mechanism in detail and also to ...

  3. The role of inorganic nitrate and nitrite in CVD.

    Science.gov (United States)

    Jackson, Jacklyn; Patterson, Amanda J; MacDonald-Wicks, Lesley; McEvoy, Mark

    2017-12-01

    CVD is the leading cause of death worldwide, a consequence of mostly poor lifestyle and dietary behaviours. Although whole fruit and vegetable consumption has been consistently shown to reduce CVD risk, the exact protective constituents of these foods are yet to be clearly identified. A recent and biologically plausible hypothesis supporting the cardioprotective effects of vegetables has been linked to their inorganic nitrate content. Approximately 60-80 % inorganic nitrate exposure in the human diet is contributed by vegetable consumption. Although inorganic nitrate is a relatively stable molecule, under specific conditions it can be metabolised in the body to produce NO via the newly discovered nitrate-nitrite-NO pathway. NO is a major signalling molecule in the human body, and has a key role in maintaining vascular tone, smooth muscle cell proliferation, platelet activity and inflammation. Currently, there is accumulating evidence demonstrating that inorganic nitrate can lead to lower blood pressure and improved vascular compliance in humans. The aim of this review is to present an informative, balanced and critical review of the current evidence investigating the role of inorganic nitrate and nitrite in the development, prevention and/or treatment of CVD. Although there is evidence supporting short-term inorganic nitrate intakes for reduced blood pressure, there is a severe lack of research examining the role of long-term nitrate intakes in the treatment and/or prevention of hard CVD outcomes, such as myocardial infarction and cardiovascular mortality. Epidemiological evidence is needed in this field to justify continued research efforts.

  4. Predicting SOA from organic nitrates in the southeastern United States

    Science.gov (United States)

    Organic nitrates have been identified as an important component of ambient aerosol in the Southeast United States. In this work, we use the Community Multiscale Air Quality (CMAQ) model to explore the relationship between gas-phase production of organic nitrates and their subsequ...

  5. Nitrate and nitrite in biology, nutrition and therapeutics

    NARCIS (Netherlands)

    Lundberg, J.O.; van Faassen, E.E.H.|info:eu-repo/dai/nl/071100938; Gladwin, M.T.; Ahluwalia, A.; Benjamin, N.

    2009-01-01

    Inorganic nitrate and nitrite from endogenous or dietary sources are metabolized in vivo to nitric oxide (NO) and other bioactive nitrogen oxides. The nitrate-nitrite-NO pathway is emerging as an important mediator of blood flow regulation, cell signaling, energetics and tissue responses to hypoxia.

  6. CU(II): catalyzed hydrazine reduction of ferric nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Karraker, D.G.

    1981-11-01

    A method is described for producing ferrous nitrate solutions by the cupric ion-catalyzed reduction of ferric nitrate with hydrazine. The reaction is complete in about 1.5 hours at 40/sup 0/C. Hydrazoic acid is also produced in substantial quantities as a reaction byproduct.

  7. Biological nitrate removal from synthetic wastewater using a fungal ...

    African Journals Online (AJOL)

    A series of lignocellulosic fungi, capable of cellulase and/or xylanase production, were isolated from soil to be used for cellulose degradation and nitrate removal from nitrate-rich wastewater in simple one-stage anaerobic bioreactors containing grass cuttings as source of cellulose. The fungal consortium, consisting of six ...

  8. Nitrate, Nitrite, and Ammonium Variability in Drinking Water Distribution Systems.

    Science.gov (United States)

    Schullehner, Jörg; Stayner, Leslie; Hansen, Birgitte

    2017-03-09

    Accurate assessments of exposure to nitrate in drinking water is a crucial part of epidemiological studies investigating long-term adverse human health effects. However, since drinking water nitrate measurements are usually collected for regulatory purposes, assumptions on (1) the intra-distribution system variability and (2) short-term (seasonal) concentration variability have to be made. We assess concentration variability in the distribution system of nitrate, nitrite, and ammonium, and seasonal variability in all Danish public waterworks from 2007 to 2016. Nitrate concentrations at the exit of the waterworks are highly correlated with nitrate concentrations within the distribution net or at the consumers' taps, while nitrite and ammonium concentrations are generally lower within the net compared with the exit of the waterworks due to nitrification. However, nitrification of nitrite and ammonium in the distribution systems only results in a relatively small increase in nitrate concentrations. No seasonal variation for nitrate, nitrite, or ammonium was observed. We conclude that nitrate measurements taken at the exit of the waterworks are suitable to calculate exposures for all consumers connected to that waterworks and that sampling frequencies in the national monitoring programme are sufficient to describe temporal variations in longitudinal studies.

  9. Seasonal Distribution of Nitrate and Nitrite Levels in Eleme Abattoir ...

    African Journals Online (AJOL)

    The study deals with the seasonal distribution of nitrate (NO3) and nitrite (NO2) levels in Eleme Abattoir environment. Samples of soil, surface water and groundwater were collected from areas unaffected and those affected by abattoir activities. For the soils from the affected area and control points respectively, nitrate levels ...

  10. Ginger-supplemented diet ameliorates ammonium nitrate-induced ...

    African Journals Online (AJOL)

    The present study was designed to evaluate the capacity of ginger to repair the oxidative stress induced by ammonium nitrate. 50 male rats were divided into 5 groups; they underwent an oral treatment of ammonium nitrate and/or ginger (N mg/kg body weight + G% in diet) during 30 days. Group I served as control (C); ...

  11. Nitrate leaching and pesticide use in energy crops

    DEFF Research Database (Denmark)

    Jørgensen, Uffe

    2006-01-01

    Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well.......Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well....

  12. Nitrite and nitrate determinations in plasma: a critical evaluation

    NARCIS (Netherlands)

    Moshage, H.; Kok, B.; Huizenga, J. R.; Jansen, P. L.

    1995-01-01

    Plasma nitrite and nitrate determinations are increasingly being used in clinical chemistry as markers for the activity of nitric oxide synthase and the production of nitric oxide radicals. However, a systematic evaluation of the determination of nitrite and nitrate in plasma has not been performed.

  13. State of nitrate pollution in groundwater in South Africa

    CSIR Research Space (South Africa)

    Maherry, A

    2010-09-01

    Full Text Available The study of nitrate concentrations in South and southern Africa is not a new subject (Tredoux and Talma, 2006, Tredoux et al., 2004), with the publication of a nitrate distribution map in 2001. However, these studies were constrained by the amount...

  14. Removal of phosphate and nitrate from aqueous solution using ...

    African Journals Online (AJOL)

    The aim of the present study was the removal of phosphate and nitrate by sodium alginate seagrass (Cymodocea rotundata) beads from aqueous solutions. The adsorption characteristics of phosphate and nitrate on the seagrass beads were optimized under different operational parameters like adsorbent dosage, initial ...

  15. Nitration of Substituted Phenols by Different Efficient Heterogeneous ...

    African Journals Online (AJOL)

    NJD

    sulphate (III) and 4) silica sulphuric acid (IV) in CH2Cl2 at room temperature and high yields. Optimum conditions for theses systems and the regioselectivities of the reactions are reported. KEYWORDS. Nitration, nitrophenols, sodium nitrate, oxalic acid dihydrate, sodium hydrogen sulphate, aluminum hydrogen sulphate, ...

  16. determination of nitrite, nitrate and total nitrogen in vegetable samples

    African Journals Online (AJOL)

    The above colour reaction system has been applied successfully for the determination of nitrite, nitrate and total nitrogen in vegetable samples. Unreduced samples give direct measure for nitrite whilst reduction of samples by copperized-cadmium column gives total nitrogen content and their difference shows nitrate content ...

  17. Determination of Nitrate Concentrations in Dutsin-MA Fadama Land ...

    African Journals Online (AJOL)

    Chemical analysis of water from Dutsinma Fadama Land was conducted for ten consecutive months (January to October) using Spectrophotometric measurement, to determine the level of nitrate in the water. The result of the study showed that the level of nitrate exceeded WHO recommended value in all the sampling sites.

  18. Nitrate-nitrogen removal with small-scale reverse osmosis ...

    African Journals Online (AJOL)

    The nitrate-nitrogen concentration in water supplied to clinics in Limpopo Province is too high to be fit for human consumption (35 to 75 mg/ℓ NO3-N). Therefore, small-scale technologies (reverse osmosis, ion-exchange and electrodialysis) were evaluated for nitrate-nitrogen removal to make the water potable (< 10 mg/ℓ ...

  19. Removal of Nitrate From Aqueous Solution Using Rice Chaff

    Directory of Open Access Journals (Sweden)

    Dehghani

    2015-09-01

    Full Text Available Background Nitrate is largely dissolved in the surface and ground water, due to its high solubility. Continual uptake of nitrite through drinking water can lead to problems and diseases (such as blue baby for humans, especially children. Objectives The aim of this study was to develop a new and inexpensive method for the removal of nitrate from water. In this regard, the possibility of using chaff for removal of nitrate from aqueous solutions was studied and the optimum operating conditions of nitrate removal was determined. Materials and Methods This is a cross-sectional study conducted in laboratory scale. The UV spectrophotometer at a wavelength of maximum absorbance (220 nm was used to determine the nitrate concentration. The effect of pH, amount of chaff, temperature, and contact time were investigated. Results The result of this study revealed that chaff as an absorbent could remove nitrate from solutions, and the efficiency of adsorption increased as contact time increased from 5 to 30 minutes, amount of chaff increased from 1 to 3 g, temperature increased in a range of 300 - 400°C and the amount of pH decreased from 10 to 3. The maximum adsorption rate was around pH 3 (53.14%. Conclusions It was shown that the removal efficiency of nitrate was directly proportional to the amount of chaff, temperature, and contact time but inversely to the pH. This study showed that nitrate removal by chaff is a promising technique.

  20. Diatoms respire nitrate to survive dark and anoxic conditions

    DEFF Research Database (Denmark)

    Kamp, Anja; de Beer, Dirk; Nitsch, Jana L.

    2011-01-01

    +, indicating dissimilatory nitrate reduction to ammo- nium (DNRA). DNRA is an anaerobic respiration process that is known mainly from prokaryotic organisms, and here shown as dis- similatory nitrate reduction pathway used by a eukaryotic photo- troph. Similar to large sulfur bacteria and benthic foraminifera...

  1. Spatial assessment of animal manure spreading and groundwater nitrate pollution

    Directory of Open Access Journals (Sweden)

    Roberta Infascelli

    2009-11-01

    Full Text Available Nitrate concentration in groundwater has frequently been linked to non-point pollution. At the same time the existence of intensive agriculture and extremely intensive livestock activity increases the potential for nitrate pollution in shallow groundwater. Nitrate used in agriculture could cause adverse effects on human and animal health. In order to evaluate the groundwater nitrate pollution, and how it might evolve in time, it is essential to develop control systems and to improve policies and incentives aimed at controlling the amount of nitrate entering downstream water systems. The province of Caserta in southern Italy is characterized by high levels of animal manure loading. A comparison between manure nitrogen production and nitrate concentration in groundwater was carried out in this area, using geostatistical tools and spatial statistics. The results show a discrepancy between modelling of nitrate leaching and monitoring of the groundwater and, moreover, no spatial correlation between nitrogen production in livestock farms and nitrate concentration in groundwater, suggesting that producers are not following the regulatory procedures for the agronomic use of manure. The methodology developed in this paper could be applied also in other regions in which European Union fertilization plans are not adequately followed.

  2. Light-induced protein nitration and degradation with HONO emission

    Science.gov (United States)

    Meusel, Hannah; Elshorbany, Yasin; Kuhn, Uwe; Bartels-Rausch, Thorsten; Reinmuth-Selzle, Kathrin; Kampf, Christopher J.; Li, Guo; Wang, Xiaoxiang; Lelieveld, Jos; Pöschl, Ulrich; Hoffmann, Thorsten; Su, Hang; Ammann, Markus; Cheng, Yafang

    2017-10-01

    Proteins can be nitrated by air pollutants (NO2), enhancing their allergenic potential. This work provides insight into protein nitration and subsequent decomposition in the presence of solar radiation. We also investigated light-induced formation of nitrous acid (HONO) from protein surfaces that were nitrated either online with instantaneous gas-phase exposure to NO2 or offline by an efficient nitration agent (tetranitromethane, TNM). Bovine serum albumin (BSA) and ovalbumin (OVA) were used as model substances for proteins. Nitration degrees of about 1 % were derived applying NO2 concentrations of 100 ppb under VIS/UV illuminated conditions, while simultaneous decomposition of (nitrated) proteins was also found during long-term (20 h) irradiation exposure. Measurements of gas exchange on TNM-nitrated proteins revealed that HONO can be formed and released even without contribution of instantaneous heterogeneous NO2 conversion. NO2 exposure was found to increase HONO emissions substantially. In particular, a strong dependence of HONO emissions on light intensity, relative humidity, NO2 concentrations and the applied coating thickness was found. The 20 h long-term studies revealed sustained HONO formation, even when concentrations of the intact (nitrated) proteins were too low to be detected after the gas exchange measurements. A reaction mechanism for the NO2 conversion based on the Langmuir-Hinshelwood kinetics is proposed.

  3. Effect of nitrate on anaerobic azo dye reduction.

    Science.gov (United States)

    Cirik, Kevser; Kitiş, Mehmet; Çinar, Özer

    2013-01-01

    The aim of the study was to investigate the effect of nitrate on anaerobic color removal efficiencies. For this aim, anaerobic-aerobic sequencing batch reactor (SBR) fed with a simulated textile effluent including Remazol Brilliant Violet 5R azo dye was operated with a total cycle time of 12 h, including anaerobic (6 h) and aerobic cycles (6 h). Microorganism grown under anaerobic phase of the reactor was exposed to different amounts of competitive electron acceptor (nitrate) and performance of the system was determined by monitoring color removal efficiency, nitrate removal, nitrite formation and removal, oxidation reduction potential, color removal rate, chemical oxygen demand (COD), specific anaerobic enzyme (azo reductase) and aerobic enzyme (catechol 1,2 dioxygenase), and formation and removal of aromatic amines. Variations of population dynamics of microorganisms exposed to various amount of nitrate were identified by denaturing gradient gel electrophoresis (DGGE). It was found that nitrate has adverse effect on anaerobic color removal efficiency and color removal was achieved after denitrification process was completed. It was found that nitrate stimulates the COD removal efficiency and accelerates the COD removal in the first hour of anaerobic phase. About 90 % total COD removal efficiencies were achieved in which microorganism exposed to increasing amount of nitrate. Population dynamics of microorganisms exposed to various amount of nitrate were changed and diversity was increased.

  4. Distribution of nitrate in the water resources of Pakistan

    African Journals Online (AJOL)

    AJL

    Full Length Research Paper. Distribution of nitrate in the water resources of. Pakistan. Muhammad Aslam Tahir* and Hifza Rasheed. Pakistan Council of Research in Water Resources, Islamabad, Pakistan. Accepted 8 September, 2008. Water quality monitoring activities have recognized the nitrate contamination in the ...

  5. Biochemistry of protein tyrosine nitration in cardiovascular pathology.

    Science.gov (United States)

    Peluffo, Gonzalo; Radi, Rafael

    2007-07-15

    Several pathologies of the cardiovascular system are associated with an augmented production of nitric oxide and/or superoxide-derived oxidants and/or alteration in the antioxidant detoxification pathways that lead to nitroxidative stress. One important consequence of these reactive intermediates at the biochemical level is the nitration of protein tyrosines, which is performed through either of two of the relevant nitration pathways that operate in vivo, namely peroxynitrite and heme peroxidase-dependent nitration. Proteins nitrated at tyrosine residues have been detected in several compartments of the cardiovascular system. In this review a selection of nitrated proteins in plasma (fibrinogen, plasmin, Apo-1), vessel wall (Apo-B, cyclooxygenase, prostaglandin synthase, Mn-superoxide dismutase) and myocardium (myofibrillar creatine kinase, alpha-actinin, sarcoplasmic reticulum Ca(2+) ATPase) are analyzed in the context of cardiovascular disease. Nitration of tyrosine can affect protein function, which could directly link nitroxidative stress to the molecular alterations found in disease. While some proteins are inactivated by nitration (e.g. Mn-SOD) others undergo a gain-of-function (e.g. fibrinogen) that can have an ample impact on the pathophysiology of the cardiovascular system. Nitrotyrosine is also emerging as a novel independent marker of cardiovascular disease. Pharmacological strategies directed towards inhibiting protein nitration will assist to shed light on the relevance of this post-translational modification to human cardiovascular pathology.

  6. Occurrence and Toxicological Significance of Nitrate and Nitrite in ...

    African Journals Online (AJOL)

    Aim: To determine and evaluate the levels of nitrate and nitrite in some commercial infant formula in view of the health implications of these factors. Method: Nitrate and nitrite, which may create significant health problems in infants, were determined in four commercial infant formula. The public health and toxicological ...

  7. determination of nitrate concentrations in dutsin-ma fadama land

    African Journals Online (AJOL)

    DR. AMINU

    2014-06-01

    Jun 1, 2014 ... However, children under one year of age and pregnant women are at risk for adverse effects. Records have shown that infants are typically exposed to unsafe levels of nitrate in drinking water when it is used to make up formula milk or other types of feeds. In older children and adults, nitrate is absorbed and.

  8. Distribution and Sources of Nitrate-Nitrogen in Kansas Groundwater

    Directory of Open Access Journals (Sweden)

    Margaret A. Townsend

    2001-01-01

    Full Text Available Kansas is primarily an agricultural state. Irrigation water and fertilizer use data show long- term increasing trends. Similarly, nitrate-N concentrations in groundwater show long-term increases and exceed the drinking-water standard of 10 mg/l in many areas. A statistical analysis of nitrate-N data collected for local and regional studies in Kansas from 1990 to 1998 (747 samples found significant relationships between nitrate-N concentration with depth, age, and geographic location of wells. Sources of nitrate-N have been identified for 297 water samples by using nitrogen stable isotopes. Of these samples, 48% showed fertilizer sources (+2 to +8 and 34% showed either animal waste sources (+10 to +15 with nitrate-N greater than 10 mg/l or indication that enrichment processes had occurred (+10 or above with variable nitrate-N or both. Ultimate sources for nitrate include nonpoint sources associated with past farming and fertilization practices, and point sources such as animal feed lots, septic systems, and commercial fertilizer storage units. Detection of nitrate from various sources in aquifers of different depths in geographically varied areas of the state indicates that nonpoint and point sources currently impact and will continue to impact groundwater under current land uses.

  9. Nitration of phenolic compounds and oxidation of hydroquinones ...

    Indian Academy of Sciences (India)

    agrochemicals, perfumes, and plastics.1–3 Traditionally, the nitration of aromatic rings was accomplished with mixed concentrated nitric-sulfuric acids. This reaction is notoriously unselective for nitration of substituted aromatic compounds such as phenols and anilines because they may be oxidized or polynitrated under.

  10. Influences of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen and soil salt-ion leaching.

    Science.gov (United States)

    Yu, Qiaogang; Ye, Xuezhu; Chen, Yingxu; Zhang, Zhijian; Tian, Guangming

    2008-01-01

    An undisturbed heavy clay soil column experiment was conducted to examine the influence of the new nitrification inhibitor, 3,4-dimethylpyrazole phosphate (DMPP), on nitrogen and soil salt-ion leaching. Regular urea was selected as the nitrogen source in the soil. The results showed that the cumulative leaching losses of soil nitrate-N under the treatment of urea with DMPP were from 57.5% to 63.3% lower than those of the treatment of urea without DMPP. The use of nitrification inhibitors as nitrate leaching retardants may be a proposal in regulations to prevent groundwater contaminant. However, there were no great difference between urea and urea with DMPP treatments on ammonium-N leaching. Moreover, the soil salt-ion leaching losses of Ca2+, Mg2+, K+, and Na+ were reduced from 26.6% to 28.8%, 21.3% to 27.8%, 33.3% to 35.5%, and 21.7% to 32.1%, respectively. So, the leaching losses of soil salt-ion were declined for nitrification inhibitor DMPP addition, being beneficial to shallow groundwater protection and growth of crop. These results indicated the possibility of ammonium or ammonium producing compounds using nitrification inhibitor DMPP to control the nitrate and nutrient cation leaching losses, minimizing the risk of nitrate pollution in shallow groundwater.

  11. Modulation of intracellular calcium levels by calcium lactate affects colon cancer cell motility through calcium-dependent calpain.

    Directory of Open Access Journals (Sweden)

    Pasupathi Sundaramoorthy

    Full Text Available Cancer cell motility is a key phenomenon regulating invasion and metastasis. Focal adhesion kinase (FAK plays a major role in cellular adhesion and metastasis of various cancers. The relationship between dietary supplementation of calcium and colon cancer has been extensively investigated. However, the effect of calcium (Ca2+ supplementation on calpain-FAK-motility is not clearly understood. We sought to identify the mechanism of FAK cleavage through Ca2+ bound lactate (CaLa, its downstream signaling and role in the motility of human colon cancer cells. We found that treating HCT116 and HT-29 cells with CaLa immediately increased the intracellular Ca2+ (iCa2+ levels for a prolonged period of time. Ca2+ influx induced cleavage of FAK into an N-terminal FAK (FERM domain in a dose-dependent manner. Phosphorylated FAK (p-FAK was also cleaved in to its p-N-terminal FAK. CaLa increased colon cancer cells motility. Calpeptin, a calpain inhibitor, reversed the effects of CaLa on FAK and pFAK cleavage in both cancer cell lines. The cleaved FAK translocates into the nucleus and modulates p53 stability through MDM2-associated ubiquitination. CaLa-induced Ca2+ influx increased the motility of colon cancer cells was mediated by calpain activity through FAK and pFAK protein destabilization. In conclusion, these results suggest that careful consideration may be given in deciding dietary Ca2+ supplementation to patient undergoing treatment for metastatic cancer.

  12. 21 CFR 184.1187 - Calcium alginate.

    Science.gov (United States)

    2010-04-01

    ... 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

    2001-01-01

    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. Src Dependent Pancreatic Acinar Injury Can Be Initiated Independent of an Increase in Cytosolic Calcium.

    Directory of Open Access Journals (Sweden)

    Vivek Mishra

    Full Text Available Several deleterious intra-acinar phenomena are simultaneously triggered on initiating acute pancreatitis. These culminate in acinar injury or inflammatory mediator generation in vitro and parenchymal damage in vivo. Supraphysiologic caerulein is one such initiator which simultaneously activates numerous signaling pathways including non-receptor tyrosine kinases such as of the Src family. It also causes a sustained increase in cytosolic calcium- a player thought to be crucial in regulating deleterious phenomena. We have shown Src to be involved in caerulein induced actin remodeling, and caerulein induced changes in the Golgi and post-Golgi trafficking to be involved in trypsinogen activation, which initiates acinar cell injury. However, it remains unclear whether an increase in cytosolic calcium is necessary to initiate acinar injury or if injury can be initiated at basal cytosolic calcium levels by an alternate pathway. To study the interplay between tyrosine kinase signaling and calcium, we treated mouse pancreatic acinar cells with the tyrosine phosphatase inhibitor pervanadate. We studied the effect of the clinically used Src inhibitor Dasatinib (BMS-354825 on pervanadate or caerulein induced changes in Src activation, trypsinogen activation, cell injury, upstream cytosolic calcium, actin and Golgi morphology. Pervanadate, like supraphysiologic caerulein, induced Src activation, redistribution of the F-actin from its normal location in the sub-apical area to the basolateral areas, and caused antegrade fragmentation of the Golgi. These changes, like those induced by supraphysiologic caerulein, were associated with trypsinogen activation and acinar injury, all of which were prevented by Dasatinib. Interestingly, however, pervanadate did not cause an increase in cytosolic calcium, and the caerulein induced increase in cytosolic calcium was not affected by Dasatinib. These findings suggest that intra-acinar deleterious phenomena may be initiated

  15. Calcium phosphates for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-01

    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)

  16. Polysulfide calcium as multyfunctional product

    Directory of Open Access Journals (Sweden)

    G. Abramova

    2012-12-01

    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.

  17. [Calcium metabolism after the menopause].

    Science.gov (United States)

    Kanovitch, D; Klotz, H P

    1976-02-16

    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.

  18. Calcium-sensing beyond neurotransmitters

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Han, Weiping

    2009-01-01

    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...

  19. Anoxic Activated Sludge Monitoring with Combined Nitrate and Titrimetric Measurements

    DEFF Research Database (Denmark)

    Petersen, B.; Gernaey, Krist; Vanrolleghem, P.A.

    2002-01-01

    An experimental procedure for anoxic activated sludge monitoring with combined nitrate and titrimetric measurements is proposed and evaluated successfully with two known carbon sources, (-)acetate and dextrose. For nitrate measurements an ion-selective nitrate electrode is applied to allow...... for frequent measurements, and thereby the possibility for detailed determination of the denitrification biokinetics. An internal nitrate electrode calibration is implemented in the experiments to avoid the often-encountered electrode drift problem. It was observed that the best experimental design...... was with the carbon source in excess, since excess nitrate provoked nitrite build-up thereby complicating the data interpretation. A conceptual model could quantitatively describe the experimental observations and thus link the experimentally measured proton production with the consumption of electron acceptor...

  20. 76 FR 23569 - Termination of the Suspension Agreement on Solid Fertilizer Grade Ammonium Nitrate From the...

    Science.gov (United States)

    2011-04-27

    ... International Trade Administration Termination of the Suspension Agreement on Solid Fertilizer Grade Ammonium... (``AD'') Investigation on Solid Fertilizer Grade Ammonium Nitrate from the Russian Federation (``the... determine whether imports of solid fertilizer grade ammonium nitrate (``ammonium nitrate'') from Russia were...

  1. Silver-doped calcium phosphate nanoparticles: synthesis, characterization, and toxic effects toward mammalian and prokaryotic cells.

    Science.gov (United States)

    Peetsch, Alexander; Greulich, Christina; Braun, Dieter; Stroetges, Christian; Rehage, Heinz; Siebers, Bettina; Köller, Manfred; Epple, Matthias

    2013-02-01

    Spherical silver-doped calcium phosphate nanoparticles were synthesized in a co-precipitation route from calcium nitrate/silver nitrate and ammonium phosphate in a continuous process and colloidally stabilized by carboxymethyl cellulose. Nanoparticles with 0.39 wt% silver content and a diameter of about 50-60 nm were obtained. The toxic effects toward mammalian and prokaryotic cells were determined by viability tests and determination of the minimal inhibitory and minimal bactericidal concentrations (MIC and MBC). Three mammalian cells lines, i.e. human mesenchymal stem cells (hMSC) and blood peripheral mononuclear cells (PBMC, monocytes and T-lymphocytes), and two prokaryotic strains, i.e. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were used. Silver-doped calcium phosphate nanoparticles and silver acetate showed similar effect toward mammalian and prokaryotic cells with toxic silver concentrations in the range of 1-3 μg mL(-1). Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Thermal Decomposition of Nitrated Tributyl Phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Paddleford, D.F. [Westinghouse Savannah River Company, Aiken, SC (United States); Hou, Y.; Barefield, E.K.; Tedder, D.W.; Abdel-Khalik, S.I. [Georgia Institute of Technology, GA (United States)

    1995-01-01

    Contact between tributyl phosphate and aqueous solutions of nitric acid and/or heavy metal nitrate salts at elevated temperatures can lead to exothermic reactions of explosive violence. Even though such operations have been routinely performed safely for decades as an intrinsic part of the Purex separation processes, several so-called ``red oil`` explosions are known to have occurred in the United States, Canada, and the former Soviet Union. The most recent red oil explosion occurred at the Tomsk-7 separations facility in Siberia, in April 1993. That explosion destroyed part of the unreinforced masonry walls of the canyon-type building in which the process was housed, and allowed the release of a significant quantity of radioactive material.

  3. Removal of gadolinium nitrate from heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, E.W.

    2000-03-22

    Work was conducted to develop a cost-effective process to purify 181 55-gallon drums containing spent heavy water moderator (D2O) contaminated with high concentrations of gadolinium nitrate, a chemical used as a neutron poison during former nuclear reactor operations at the Savannah River Site (SRS). These drums also contain low level radioactive contamination, including tritium, which complicates treatment options. Presently, the drums of degraded moderator are being stored on site. It was suggested that a process utilizing biological mechanisms could potentially lower the total cost of heavy water purification by allowing the use of smaller equipment with less product loss and a reduction in the quantity of secondary waste materials produced by the current baseline process (ion exchange).

  4. [Mechanisms of nitroxide-ergic dysregulation in tissues of parodontium in rats under combined excessive sodium nitrate and fluoride intake].

    Science.gov (United States)

    Богданов, Алексей В; Гришко, Юлия М; Костенко, Виталий А

    intake of inorganic nitrates is typically accompanied by production of excessive amount of nitric oxide (NO), which level is maintained by the mechanism of autoregulation known as the NO cycle. Hypothetically, this process may be disrupted with fluorides that are able to suppress arginase pathway of L-arginine metabolism, which competes with NO-synthase pathway. to study mechanisms of disregulation of oxidative (NO-synthase) and non-oxidative (arginase) metabolic pathways of L-arginine in the tissues of periodontium under combined excessive sodium nitrate and fluoride intake. these investigations were carried out on 90 white Wistar rats. Homogenates of parodontium soft tissues were used to assess spectrophotometrically the total activities of NO-synthase (NOS), arginase, ornithine decarboxylase as well as the peroxynitrite concentration. typical for the isolated sodium nitrate administration inhibition of total NOS activity varies under combined administration of nitrate and sodium fluoride and is usually manifested by its hyperactivation that is accompanied by an increase in peroxynitrite concentration. At this time arginase and ornithine decarboxylase activity is observed to be substantially reduced. The administration of aminoguanidine, an iNOS inhibitor, (20 mg/kg, twice a week during the experiment) increases arginase and ornithine decarboxylase activities, and the administration of L-arginine (500 mg/kg, twice a week) results in the increase of arginase activity. The administration of L-selenomethionine, a peroxynitrite scavenger (3 mg/kg, twice a week), and JSH-23 (4-methyl-N-(3-phenylpropyl) benzene-1,2-diamine, an inhibitor of NF-κB activation (1 mg/kg, twice a week) for modeling binary nitrate and fluoride intoxication reduces the total concentration of NOS activity and peroxynitrite concentration, and increases ornithine decarboxylase activity. the combined effect of nitrate and sodium fluoride for 30 days leads to disregulatory increased activity of NO

  5. The exo-proteome and exo-metabolome of Nostoc punctiforme (Cyanobacteria) in the presence and absence of nitrate.

    Science.gov (United States)

    Vilhauer, Laura; Jervis, Judith; Ray, W Keith; Helm, Richard F

    2014-05-01

    The ability of nitrogen-fixing filamentous Cyanobacteria to adapt to multiple environments comes in part from assessing and responding to external stimuli, an event that is initiated in the extracellular milieu. While it is known that these organisms produce numerous extracellular substances, little work has been done to characterize both the metabolites and proteins present under standard laboratory growth conditions. We have assessed the extracellular milieu of Nostoc punctiforme when grown in liquid culture in the presence and absence of a nitrogen source (nitrate). The extracellular proteins identified were enriched in integrin β-propellor domains and calcium-binding sites with sequences unique to N. punctiforme, supporting a role for extracellular proteins in modulating species-specific recognition and behavior processes. Extracellular proteases are present and active under both conditions, with the cells grown with nitrate having a higher activity when normalized to chlorophyll levels. The released metabolites are enriched in peptidoglycan-derived tetrasaccharides, with higher levels in nitrate-free media.

  6. Characterisation of occupational exposure to air contaminants in a nitrate fertiliser production plant.

    Science.gov (United States)

    Hovland, Kristin H; Thomassen, Yngvar; Skaugset, Nils Petter; Skyberg, Knut; Skogstad, Marit; Bakke, Berit

    2012-08-01

    The aim of this study was to characterise personal exposures to dust, acid vapours, and gases among workers in a Norwegian nitrate fertiliser production plant, as part of an ongoing epidemiological study. In total, 178 inhalable and 179 thoracic aerosol mass fraction samples were collected from randomly chosen workers (N = 141) from three compound fertiliser departments (A, B and C), a calcium nitrate fertiliser production department, nitric acid- and ammonia-production departments, and a shipping department. The overall median inhalable and thoracic aerosol mass concentrations were generally low (1.1 mg m(-3) (min-max: <0.93-45) and 0.21 mg m(-3) (min-max: <0.085-11), respectively). Workers at the compound fertiliser departments B and C had significantly higher inhalable aerosol mass air concentrations compared to the other departments (p < 0.05), except for compound fertiliser department A; however, the difference between the compound fertiliser department C and calcium nitrate department was slightly above the significant level. Workers at the compound fertiliser department A had significantly higher thoracic aerosol mass air concentrations compared to the other departments (p < 0.05), except for compound fertiliser departments B and C. The results indicate that the extrathoracic aerosol fraction of the aerosol compared to the thoracic fraction dominated in most departments. Measurement of the main constituents Ca, K, Mg, and P in the water-soluble and water-insoluble aerosol mass fractions showed that the air concentrations of these elements were low. There is, however, a shift towards more water-soluble species as the production goes from raw material with phosphate rock towards the final product of fertilisers. Overall, the arithmetic mean of water-soluble Ca in the thoracic mass fraction was 51% (min-max: 1-100). A total of 169 personal samples were analysed for HNO(3) vapour and HF. The highest median concentration of HNO(3) (0.63 mg m(-3)) was in the

  7. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Science.gov (United States)

    2010-04-01

    ... 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...

  8. Influence of maleic acid copolymers on calcium orthophosphates crystallization at low temperature

    Science.gov (United States)

    Pelin, Irina M.; Popescu, Irina; Suflet, Dana M.; Aflori, Magdalena; Bulacovschi, Victor

    2013-08-01

    The goal of this study was to investigate the maleic acid copolymers role on calcium orthophosphates crystallization at low temperature. In this respect, two maleic acid copolymers with different structures [poly(sodium maleate-co-vinyl acetate) and poly(sodium maleate-co-methyl methacrylate)] were used. The syntheses of the calcium orthophosphates in the absence and in the presence of the copolymers were performed through the wet chemical method using calcium nitrate, ammonium dihydrogen phosphate and ammonium hydroxide as reactants. The syntheses were monitored in situ by potentiometric and conductometric measurements. To ensure the transformation of less thermodynamically stable calcium orthophosphates into more stable forms, the samples were aged 30 days in mother solutions, at room temperature. The presence of the copolymers in the final products was evidenced by FTIR spectroscopy and thermogravimetric analysis. Scanning and transmission electron microscopy and laser light scattering measurements gave information about the composites morphology and the size of the formed structures. X-ray diffraction evidenced that, as a function of comonomer structure and of copolymer concentration, the products could contain hydroxyapatite with low crystallinity, calcium-deficient or carbonated hydroxyapatite. At high concentration of poly(sodium maleate-co-methyl methacrylate) the transformation of brushite into apatitic structures was inhibited.

  9. Neocortical GABA release at high intracellular sodium and low extracellular calcium: an anti-seizure mechanism.

    Science.gov (United States)

    Rassner, Michael P; Moser, Andreas; Follo, Marie; Joseph, Kevin; van Velthoven-Wurster, Vera; Feuerstein, Thomas J

    2016-04-01

    In epilepsy, the GABA and glutamate balance may be disrupted and a transient decrease in extracellular calcium occurs before and during a seizure. Flow Cytometry based fluorescence activated particle sorting experiments quantified synaptosomes from human neocortical tissue, from both epileptic and non-epileptic patients (27.7% vs. 36.9% GABAergic synaptosomes, respectively). Transporter-mediated release of GABA in human and rat neocortical synaptosomes was measured using the superfusion technique for the measurement of endogenous GABA. GABA release was evoked by either a sodium channel activator or a sodium/potassium-ATPase inhibitor when exocytosis was possible or prevented, and when the sodium/calcium exchanger was active or inhibited. The transporter-mediated release of GABA is because of elevated intracellular sodium. A reduction in the extracellular calcium increased this release (in both non-epileptic and epileptic, except Rasmussen encephalitis, synaptosomes). The inverse was seen during calcium doubling. In humans, GABA release was not affected by exocytosis inhibition, that is, it was solely transporter-mediated. However, in rat synaptosomes, an increase in GABA release at zero calcium was only exhibited when the exocytosis was prevented. The absence of calcium amplified the sodium/calcium exchanger activity, leading to elevated intracellular sodium, which, together with the stimulation-evoked intracellular sodium increment, enhanced GABA transporter reversal. Sodium/calcium exchange inhibitors diminished GABA release. Thus, an important seizure-induced extracellular calcium reduction might trigger a transporter- and sodium/calcium exchanger-related anti-seizure mechanism by augmenting transporter-mediated GABA release, a mechanism absent in rats. Uniquely, the additional increase in GABA release because of calcium-withdrawal dwindled during the course of illness in Rasmussen encephalitis. Seizures cause high Na(+) influx through action potentials. A

  10. Tyrosine-Nitrated Proteins: Proteomic and Bioanalytical Aspects.

    Science.gov (United States)

    Batthyány, Carlos; Bartesaghi, Silvina; Mastrogiovanni, Mauricio; Lima, Analía; Demicheli, Verónica; Radi, Rafael

    2017-03-01

    "Nitroproteomic" is under active development, as 3-nitrotyrosine in proteins constitutes a footprint left by the reactions of nitric oxide-derived oxidants that are usually associated to oxidative stress conditions. Moreover, protein tyrosine nitration can cause structural and functional changes, which may be of pathophysiological relevance for human disease conditions. Biological protein tyrosine nitration is a free radical process involving the intermediacy of tyrosyl radicals; in spite of being a nonenzymatic process, nitration is selectively directed toward a limited subset of tyrosine residues. Precise identification and quantitation of 3-nitrotyrosine in proteins has represented a "tour de force" for researchers. Recent Advances: A small number of proteins are preferential targets of nitration (usually less than 100 proteins per proteome), contrasting with the large number of proteins modified by other post-translational modifications such as phosphorylation, acetylation, and, notably, S-nitrosation. Proteomic approaches have revealed key features of tyrosine nitration both in vivo and in vitro, including selectivity, site specificity, and effects in protein structure and function. Identification of 3-nitrotyrosine-containing proteins and mapping nitrated residues is challenging, due to low abundance of this oxidative modification in biological samples and its unfriendly behavior in mass spectrometry (MS)-based technologies, that is, MALDI, electrospray ionization, and collision-induced dissociation. The use of (i) classical two-dimensional electrophoresis with immunochemical detection of nitrated proteins followed by protein ID by regular MS/MS in combination with (ii) immuno-enrichment of tyrosine-nitrated peptides and (iii) identification of nitrated peptides by a MIDAS™ experiment is arising as a potent methodology to unambiguously map and quantitate tyrosine-nitrated proteins in vivo. Antioxid. Redox Signal. 26, 313-328.

  11. Proteome responses to nitrate in bioethanol production contaminant Dekkera bruxellensis.

    Science.gov (United States)

    Neto, Adauto Gomes Barbosa; Pestana-Calsa, Maria Clara; de Morais, Marcos Antonio; Calsa, Tercilio

    2014-06-02

    Dekkera bruxellensis is an industrially relevant yeast, especially in bioethanol production. The capacity of D. bruxellensis to assimilate nitrate can confer advantages of this yeast over Saccharomyces cerevisiae at industrial conditions. In the present work we present the consequences of nitrate assimilation, using ammonium as reference, to the proteomics of D. bruxellensis. Thirty-four protein spots were overproduced in nitrate medium and were identified by MS-TOF/TOF analysis and were putatively identified by using local Mascot software. Apart from the overexpression of genes of nitrate metabolism, ATP synthesis and PPP and TCA pathways previously reported, cultivation on nitrate induced overproduction of glycolytic enzymes, which corroborate the high energy demand and NADH availability for nitrate assimilation. Overproduction of alcohol dehydrogenase (Adh) protein was also observed. Proteomic profile of D. bruxellensis cultivated in nitrate and described in the present work agrees with the hypothesis of metabolic flux regulation, making available the energy in the form of NADH to support nitrate assimilation. This work contributes with an initial picture of proteins presenting differential accumulation in industrial contaminant yeast, in strict association with possible metabolic responses to nitrate as sole nitrogen source in cultivation medium. The present study investigated the gene expression at translational level of yeast D. bruxellensis for nitrate assimilation. This study corroborated with biological models that consider the ability to assimilate this nitrogen source confers advantages on this yeast during the fermentation process industry. However, larger studies are needed in this way as our group is investigating new proteins under LC-MS/MS approach. Together, these studies will help in understanding the operation of networks and cellular regulation of the process of assimilation of nitrogen sources for the D. bruxellensis, unravelling new aspects of

  12. Calcium affects on vascular endpoints

    Directory of Open Access Journals (Sweden)

    Patel Vaishali B

    2012-03-01

    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.

  13. Isoprene oxidation by nitrate radical: alkyl nitrate and secondary organic aerosol yields

    Directory of Open Access Journals (Sweden)

    A. W. Rollins

    2009-09-01

    Full Text Available Alkyl nitrates and secondary organic aerosol (SOA produced during the oxidation of isoprene by nitrate radicals has been observed in the SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber chamber. A 16 h dark experiment was conducted with temperatures at 289–301 K, and maximum concentrations of 11 ppb isoprene, 62.4 ppb O3 and 31.1 ppb NOx. We find the yield of nitrates is 70±8% from the isoprene + NO3 reaction, and the yield for secondary dinitrates produced in the reaction of primary isoprene nitrates with NO3 is 40±20%. We find an effective rate constant for reaction of NO3 with the group of first generation oxidation products to be 7×10−14 molecule−1 cm3 s−1. At the low total organic aerosol concentration in the chamber (max=0.52 μg m−3 we observed a mass yield (ΔSOA mass/Δisoprene mass of 2% for the entire 16 h experiment. However a comparison of the timing of the observed SOA production to a box model simulation of first and second generation oxidation products shows that the yield from the first generation products was <0.7% while the further oxidation of the initial products leads to a yield of 14% (defined as ΔSOA/Δisoprene2x where Δisoprene2x is the mass of isoprene which reacted twice with NO3. The SOA yield of 14% is consistent with equilibrium partitioning of highly functionalized C5 products of isoprene oxidation.

  14. Solidification of Acidic, High Nitrate Nuclear Wastes by Grouting or Absorption on Silica Gel

    Energy Technology Data Exchange (ETDEWEB)

    A. K. Herbst; S. V. Raman; R. J. Kirkham

    2004-01-01

    The use of grout and silica gel were explored for the solidification of four types of acidic, high nitrate radioactive wastes. Two methods of grouting were tested: direct grouting and pre-neutralization. Two methods of absorption on silica gel were also tested: direct absorption and rotary spray drying. The waste simulant acidity varied between 1 N and 12 N. The waste simulant was neutralized by pre-blending calcium hydroxide with Portland cement and blast furnace slag powders prior to mixing with the simulant for grout solidification. Liquid sodium hydroxide was used to partially neutralize the simulant to a pH above 2 and then it was absorbed for silica gel solidification. Formulations for each of these methods are presented along with waste form characteristics and properties. Compositional variation maps for grout formulations are presented which help determine the optimum "recipe" for a particular waste stream. These maps provide a method to determine the proportions of waste, calcium hydroxide, Portland cement, and blast furnace slag that provide a waste form that meets the disposal acceptance criteria. The maps guide researchers in selecting areas to study and provide an operational envelop that produces acceptable waste forms. The grouts both solidify and stabilize the wastes, while absorption on silica gel produces a solid waste that will not pass standard leaching procedures (TCLP) if required. Silica gel wastes can be made to pass most leach tests if heated to 600ºC.

  15. REMOVAL OF ADDED NITRATE IN COTTON BURR COMPOST, MULCH COMPOST, AND PEAT: MECHANISMS AND POTENTIAL USE FOR GROUNDWATER NITRATE REMEDIATION

    Science.gov (United States)

    We conducted batch tests on the nature and kinetics of removal of added nitrate in cotton burr compost, mulch compost, and sphagnum peat that may be potentially used in a permeable reactive barrier (PRB) for groundwater nitrate remediation. A rigorous steam autoclaving protocol (...

  16. Determination of major sodium iodide symporter (NIS) inhibitors in drinking waters using ion chromatography with conductivity detector.

    Science.gov (United States)

    Cengiz, Mehmet Fatih; Bilgin, Ayse Kevser

    2016-02-20

    Goiter is an important health problem all over the world and iodine deficiency is its most common cause. Perchlorate, thiocyanate and nitrate (called as major NIS inhibitors) are known to competitively inhibit iodide uptake by the thyroid gland and thus, human exposure to major NIS inhibitors is a public health concern. In this study, an ion chromatographic method for the determination of most common NIS inhibitor ions in drinking waters was developed and validated. This is the first study where an analytical method is used for the determination of major NIS inhibitors in drinking water by an ion chromatography system in a single run. Chromatographic separations were achieved with an anion-exchange column and separated ions were identified by a conductivity detector. The method was found to be selective, linear, precise accurate and true for all of interested ions. The limits of the detections (LOD) were estimated at 0.003, 0.004 and 0.025mgL(-1) for perchlorate, thiocyanate and nitrate, respectively. Possible interference ions in drinking waters were examined for the best separation of NIS inhibitors. The excellent method validation data and proficiency test result (Z-score for nitrate: -0.1) of the FAPAS(®) suggested that the developed method could be applied for determination of NIS inhibitor residues in drinking waters. To evaluate the usefulness of the method, 75 drinking water samples from Antalya/Turkey were analyzed for NIS inhibitors. Perchlorate concentrations in the samples ranged from not detected (less than LOD) to 0.07±0.02mgL(-1) and the range of nitrate concentrations were found to be 3.60±0.01mgL(-1) and 47.42±0.40mgL(-1). No thiocyanate residues were detected in tested drinking water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Anti-corrosion performance of composite inhibitor for N80 steel in NaIO4 solution

    Science.gov (United States)

    Zhao, Liqiang; Zhu, Yanhua; Zhang, Jian; Liu, Pingli; Liu, Yigang; Meng, Xianghai; Liu, Changlong

    2017-10-01

    A kind of composite inhibitor was chosen and compounded by zinc nitrate, sodium silicate, sodium tri-polyphosphate by orthogonal design method. The anti-corrosion performance of this composite inhibitor for N80 steel in sodium periodate solution was investigated through electrochemical measurements and soaking experiments, followed by corrosion morphology observations and corrosion products analysis. The results indicated that the composite inhibitor is a cathodic inhibitor and suitable for application in sodium periodate solution, the inhibition efficiency of optimal inhibitor can reach to 95.3%. The composite inhibitor inhibited the corrosion process by preventing the contact of corrosive medium and steel surface through formation of a protective film on the surface of N80 steel.

  18. Ratiometric analysis of fura red by flow cytometry: a technique for monitoring intracellular calcium flux in primary cell subsets.

    Directory of Open Access Journals (Sweden)

    Emily R Wendt

    Full Text Available Calcium flux is a rapid and sensitive measure of cell activation whose utility could be enhanced with better techniques for data extraction. We describe a technique to monitor calcium flux by flow cytometry, measuring Fura Red calcium dye by ratiometric analysis. This technique has several advantages: 1 using a single calcium dye provides an additional channel for surface marker characterization, 2 allows robust detection of calcium flux by minority cell populations within a heterogeneous population of primary T cells and monocytes 3 can measure total calcium flux and additionally, the proportion of responding cells, 4 can be applied to studying the effects of drug treatment, simultaneously stimulating and monitoring untreated and drug treated cells. Using chemokine receptor activation as an example, we highlight the utility of this assay, demonstrating that only cells expressing a specific chemokine receptor are activated by cognate chemokine ligand. Furthermore, we describe a technique for simultaneously stimulating and monitoring calcium flux in vehicle and drug treated cells, demonstrating the effects of the Gαi inhibitor, pertussis toxin (PTX, on chemokine stimulated calcium flux. The described real time calcium flux assay provides a robust platform for characterizing cell activation within primary cells, and offers a more accurate technique for studying the effect of drug treatment on receptor activation in a heterogeneous population of primary cells.

  19. Functional, genetic and bioinformatic characterization of a calcium/calmodulin kinase gene in Sporothrix schenckii

    Directory of Open Access Journals (Sweden)

    Rodriguez-del Valle Nuri

    2007-11-01

    Full Text Available Abstract Background Sporothrix schenckii is a pathogenic, dimorphic fungus, the etiological agent of sporotrichosis, a subcutaneous lymphatic mycosis. Dimorphism in S. schenckii responds to second messengers such as cAMP and calcium, suggesting the possible involvement of a calcium/calmodulin kinase in its regulation. In this study we describe a novel calcium/calmodulin-dependent protein kinase gene in S. schenckii, sscmk1, and the effects of inhibitors of calmodulin and calcium/calmodulin kinases on the yeast to mycelium transition and the yeast cell cycle. Results Using the PCR homology approach a new member of the calcium/calmodulin kinase family, SSCMK1, was identified in this fungus. The cDNA sequence of sscmk1 revealed an open reading frame of 1,221 nucleotides encoding a 407 amino acid protein with a predicted molecular weight of 45.6 kDa. The genomic sequence of sscmk1 revealed the same ORF interrupted by five introns. Bioinformatic analyses of SSCMK1 showed that this protein had the distinctive features that characterize a calcium/calmodulin protein kinase: a serine/threonine protein kinase domain and a calmodulin-binding domain. When compared to homologues from seven species of filamentous fungi, SSCMK1 showed substantial similarities, except for a large and highly variable region that encompasses positions 330 – 380 of the multiple sequence alignment. Inhibition studies using calmodulin inhibitor W-7, and calcium/calmodulin kinase inhibitors, KN-62 and lavendustin C, were found to inhibit budding by cells induced to re-enter the yeast cell cycle and to favor the yeast to mycelium transition. Conclusion This study constitutes the first evidence of the presence of a calcium/calmodulin kinase-encoding gene in S. schenckii and its possible involvement as an effector of dimorphism in this fungus. These results suggest that a calcium/calmodulin dependent signaling pathway could be involved in the regulation of dimorphism in this fungus

  20. The influence of potassium and calcium ions on nitrogen metabolism of cucumber seedlings

    Directory of Open Access Journals (Sweden)

    Genowefa Kubik-Dobosz

    2014-01-01

    Full Text Available It was found that K+ or Ca2+ deficiency in a nitrate or ammonium medium increased the amount of accumulated total and non-protein nitrogen in some organs of cucumber seedlings, as also caused changes in accumulated potassium and calcium. Lack of K+ or Ca2+ in a medium which did not contain nitrogen led to an increased level of glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase activity in the cotyledons and roots of cucumbers. Similar changes in the activity of these enzymes were noted in certain organs of seedlings growing in nitrate or ammonium medium with decreased K+ or Ca2+ contents, although the magnitude of these changes depended upon the applied dosage of these cations, the form of mineral nitrogen, developmental phase of plants and the plant organ dealt with.