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1

Mechanism by which ammonium bicarbonate and ammonium sulfate inhibit mycotoxigenic fungi.  

PubMed Central

In this study we examined the mechanism by which ammonium bicarbonate inhibits mycotoxigenic fungi. Elevated extracellular pH, alone, was not responsible for the antifungal activity. Although conidia of Penicillium griseofulvum and Fusarium graminearum had internal pH (pHi) values as high as 8.0 in buffer at an external pH (pHo) of 9.5, their viability was not markedly affected. The pHi values from conidia equilibrated in glycine-NaOH-buffered treatments without ammonium bicarbonate or ammonium sulfate were similar to values obtained from buffered treatments containing the ammonium salts. Thus, inhibition did not appear to be directly related to increased pHi. Ammonium sulfate in buffered media at pH greater than or equal to 8.7 was as inhibitory as ammonium bicarbonate, but was completely ineffective at pH less than or equal to 7.8. The hypothesis that free ammonia caused the fungal inhibition was tested by using ammonium sulfate as a model for ammonium bicarbonate. Viability, expressed as log CFU/ml, and percent germination of P. griseofulvum and F. graminearum decreased dramatically as the free ammonia concentration increased. Germination rate ratios (the germination rate in buffered ammonium sulfate divided by the germination rate in buffer alone) decreased linearly as the free ammonia concentration increased, further establishing NH3 as the toxic agent. Ammonium bicarbonate inhibits fungi because the bicarbonate anion supplies the alkalinity necessary to establish an antifungal concentration of free ammonia.

DePasquale, D A; Montville, T J

1990-01-01

2

Physical exercise after induced alkalosis (bicarbonate or Tris-buffer)  

Microsoft Academic Search

Summary  The influence of bicarbonate and Tris-buffer infusions on the performance capacity for maximal, brief exercise (400 m run) was studied using 10 normal males in their twenties. Run time, maximal lactate concentration and heart rate remained unchanged after the buffer infusions. As a result of the induced elevated buffering capacity, the average pH after exercise was about 0.1 unit higher.

W. Kindermann; J. Keul; G. Huber

1977-01-01

3

Formation of amino acids from ammonium bicarbonate or ammonium formate by contact glow-discharge electrolysis  

Microsoft Academic Search

In this paper, we describe the formation of amino acids from ammonium bicarbonate or ammonium formate in ammoniac~tl aqueous solution by contact glow-discharge electrolysis (CGDE). CGDE is a chemical change due to the glow discharge between a solution containing various ions or substrates and the elctrode in contact with the solution [2]. Several studies have been reported recently on the

K. Harada; S. Suzuki

1977-01-01

4

Biocompatibility and buffers: Effect of bicarbonate-buffered peritoneal dialysis fluids on peritoneal cell function  

Microsoft Academic Search

Biocompatibility and buffers: Effect of bicarbonate-buffered peritoneal dialysis fluids on peritoneal cell function.BackgroundConventional peritoneal dialysis fluids (PDF) have been shown to compromise the function of both leukocytes and human peritoneal mesothelial cells (HPMC). Various in vitro studies have identified the low initial pH in combination with high lactate content, as well as the hyperosmolality and high glucose concentration present in

Achim Jörres; Thorsten O Bender; André Finn; Janusz Witowski; Sibylle Fröhlich; Gerhard M Gahl; Ulrich Frei; Heiko Keck; Jutta Passlick-Deetjen

1998-01-01

5

Effects of ammonium bicarbonate on the electrospray mass spectra of proteins: evidence for bubble-induced unfolding.  

PubMed

Many protein investigations by electrospray ionization (ESI) mass spectrometry (MS) strive to ensure a "native" solvent environment, i.e., nondenaturing conditions up to the point of gas-phase ion formation. Ideally, these studies would employ a volatile pH buffer to mitigate changes in H(+) concentration that can occur during ESI. Ammonium acetate is a commonly used additive, despite its low buffering capacity at pH 7. Ammonium bicarbonate provides greatly improved pH stabilization, thus offering an interesting alternative. Surprisingly, protein analyses in bicarbonate at pH 7 tend to result in the formation of very high charge states, similar to those obtained when electrospraying unfolded proteins in a denaturing solvent. This effect has been reported previously (Sterling, H. J.; Cassou, C. A.; Susa, A. C.; Williams, E. R. Anal. Chem. 2012, 84, 3795), but its exact mechanistic origin remains unclear. ESI-mediated unfolding does not take place in acetate under otherwise identical conditions. We demonstrate that heating of protein-containing bicarbonate solutions results in extensive foaming, caused by CO2 outgassing. In contrast, acetate solutions do not generate foam. Protein denaturation caused by gas bubbles is a well-known phenomenon. Adsorption to the gas/liquid interface is accompanied by major conformational changes that allow the protein to act as a surfactant. The foaming of beer is a manifestation of this effect. Bubble formation in bicarbonate during ESI is facilitated by collisional and blackbody droplet heating. Our data imply that heat and bubbles act synergistically to cause unfolding during the electrospray process, while proteins reside in ESI droplets. Because of this effect we advise against the use of ammonium bicarbonate for native ESI-MS. Ammonium acetate represents a gentler droplet environment, despite its low buffering capacity. PMID:23724896

Hedges, Jason B; Vahidi, Siavash; Yue, Xuanfeng; Konermann, Lars

2013-07-01

6

Physical Compatibility of Magnesium Sulfate and Sodium Bicarbonate in a Pharmacy-compounded Bicarbonate-buffered Hemofiltration Solution  

PubMed Central

PURPOSE To assess the physical compatibility of magnesium sulfate and sodium bicarbonate in a pharmacy-compounded bicarbonate-buffered hemofiltration solution used at the National Institutes of Health Clinical Center (http://www.cc.nih.gov). METHODS Two hemofiltration fluid formulations with a bicarbonate of 50 mEq/L and a magnesium of 1.5 mEq/L or 15 mEq/L were prepared in triplicate with an automated compounding device. The hemofiltration solution with a bicarbonate of 50 mEq/L and a magnesium of 1.5 mEq/L contains the maximum concentration of additives that we use in clinical practice. The hemofiltration solution of 15 mEq/L of magnesium and 50 mEq/L of bicarbonate was used to study the physicochemical properties of this interaction. The solutions were stored without light protection at 22 to 25 °C for 48 hours. Physical compatibility was assessed by visual inspection and microscopy. The pH of the solutions was assayed at 3 to 4 hours and 52 to 53 hours after compounding. In addition, electrolyte and glucose concentrations in the solutions were assayed at two time points after preparation: 3 to 4 hours and 50 to 51 hours. RESULTS No particulate matter was observed by visual and microscopic inspection in the compounded hemofiltration solutions at 48 hours. Electrolyte and glucose concentrations and pH were similar at both time points after solution preparation. CONCLUSION Magnesium sulfate (1.5 mEq/L) and sodium bicarbonate (50 mEq/L) were physically compatible in a pharmacy-compounded bicarbonate-buffered hemofiltration solution at room temperature without light protection at 48 hours.

Moriyama, Brad; Henning, Stacey A.; Jin, Haksong; Kolf, Mike; Rehak, Nadja N.; Danner, Robert L.; Walsh, Thomas J.; Grimes, George J.

2011-01-01

7

Bicarbonate/lactate- and bicarbonate-buffered peritoneal dialysis fluids improve ex vivo peritoneal macrophage TNFalpha secretion.  

PubMed

Peritoneal macrophage (PMO) function was examined ex vivo after their in vivo exposure to either acidic, lactate-buffered solutions (PD4; 40 mM lactate, pH 5.2), bicarbonate/lactate-buffered solution (TBL; 25 mM/15 mM bicarbonate/lactate, pH 7.3), or bicarbonate-buffered solution (TB; 38 mM bicarbonate, pH 7.3), containing either 1.36 or 3.86% glucose. Initial experiments demonstrated that tumor necrosis factor-alpha (TNFalpha) release (assessed by TNF-direct immunoassay [DIA]) from PMO isolated from the peritoneal cavities of patients exposed to conventional fluid (PD4 1.36% glucose) was lowest after 30 min of intraperitoneal dwell (3591+/-1200 versus 28,946+/-9359 for 240-min dwell [pg/ml], n=5, P < 0.05). Five patients were exposed on 3 successive days to PD4, TBL, and TB for 30-min acute dwells containing 1.36% glucose in the first week and 3.86% glucose during the second. PMO TNFalpha release was assessed after ex vitro exposure to lipopolysaccharide (LPS). Exposure of PMO to TBL or TB (1.36% glucose) resulted in a significant increase in the generation of TNFalpha (pg/2 X 10(6) PMO) compared with PD4. TBL: 68,659+/-35,633, TB: 53,682+/-26,536 versus PD4 17,107+/-8996 (LPS 1.0 ng/ml, n=5 patients, P=0.043 versus PD4 for both). PMO that were recovered from PD4 and TB dwells (3.86% glucose) showed no significant difference in TNFalpha secretion (21,661+/-6934 and 23,923+/-9147, respectively). In contrast, exposure to TBL resulted in a significant increase (41,846+/-11,471) compared with PD4 (LPS 1.0 ng/ml, n=5 patients, P=0.043). These data demonstrate enhanced PMO function after in vivo exposure to bicarbonate- and bicarbonate/lactate-buffered solutions. This response was sustained in TBL alone at the highest glucose concentrations. These results suggest that the newer solutions, and particularly bicarbonate/lactate, might improve host defense status in peritoneal dialysis patients. PMID:9697673

MacKenzie, R K; Holmes, C J; Moseley, A; Jenkins, J P; Williams, J D; Coles, G A; Faict, D; Topley, N

1998-08-01

8

In vivo exposure to bicarbonate/lactate- and bicarbonate-buffered peritoneal dialysis fluids improves ex vivo peritoneal macrophage function.  

PubMed

The impact on peritoneal macrophage (PMO) function of acidic lactate-buffered (Lac-PDF [PD4]; 40 mmol/L of lactate; pH 5.2) and neutral-pH, bicarbonate-buffered (TB; 38 mmol/L of bicarbonate; pH 7. 3) and bicarbonate/lactate-buffered (TBL; 25 mmol/L of bicarbonate/15 mmol/L of lactate; pH 7.3) peritoneal dialysis fluids (PDFs) was compared during a study of continuous therapy with PD4, TB, or TBL. During a run-in phase of 6 weeks when all patients (n = 15) were treated with their regular dialysis regimen with Lac-PDF, median PMO tumor necrosis factor alpha (TNFalpha) release values were 203.6, 89.9, and 115.5 pg TNFalpha/10(6) PMO in the patients subsequently randomized to the PD4, TB, and TBL treatment groups, respectively. Median stimulated TNFalpha values (serum-treated zymosan [STZ], 10 microgram/mL) were 1,894.6, 567.3, and 554.5 pg TNFalpha/10(6) PMO in the same groups, respectively. During the trial phase of 12 weeks, when the three groups of patients (n = 5 per group) were randomized to continuous treatment with PD4, TB, or TBL, median constitutive TNFalpha release values were 204.7, 131.4, and 155.4 pg TNFalpha/10(6) PMO, respectively. Stimulated TNFalpha values (STZ, 10 microgram/mL) were 1,911, 1,832, and 1,378 pg TNFalpha/10(6) PMO in the same groups, respectively. Repeated-measures analysis of variance comparing the run-in phase with the trial phase showed that PMO TNFalpha release was significantly elevated in patients treated with both TB (P = 0.040) and TBL (P = 0.014) but not in patients treated with Lac-PDF (P = 0. 795). These data suggest that patients continuously exposed to bicarbonate- and bicarbonate/lactate-buffered PDFs might have better preserved PMO function and thus improved host defense status. PMID:10620552

Mackenzie, R K; Jones, S; Moseley, A; Holmes, C J; Argyle, R; Williams, J D; Coles, G A; Pu, K; Faict, D; Topley, N

2000-01-01

9

EFFECTS OF LIMESTONE AND SODIUM BICARBONATE BUFFERS ON RUMEN MEASUREMENTS AND RATE OF PASSAGE IN CATTLE  

Microsoft Academic Search

Summary Eight rumen-fistulated cattle (four Angus steers and four nonlactating Holstein cows) were fed a cracked corn-based concentrate (65% of dry matter) and corn silage (35% of dry matter) diet containing: (1) no buffer, (2) 2.5% limestone, (3) 2% sodium bicarbonate (NaHCO3) or (4) 1.25% limestone and 1.25% NaHCO3. Each diet was fed at approximately maintenance and-two times maintenance levels

G. L. Haaland; H. F. Tyrrell

10

An automated system for monitoring and regulating the pH of bicarbonate buffers.  

PubMed

The bicarbonate buffer is considered as the most biorelevant buffer system for the simulation of intestinal conditions. However, its use in dissolution testing of solid oral dosage forms is very limited. The reason for this is the thermodynamic instability of the solution containing hydrogen carbonate ions and carbonic acid. The spontaneous loss of carbon dioxide (CO(2)) from the solution results in an uncontrolled increase of the pH. In order to maintain the pH on the desired level, either a CO(2) loss must be completely avoided or the escaped CO(2) has to be replaced by quantitative substitution, i.e. feeding the solution with the respective amount of gas, which re-acidifies the buffer after dissociation. The present work aimed at the development of a device enabling an automatic pH monitoring and regulation of hydrogen carbonate buffers during dissolution tests. PMID:23468339

Garbacz, Grzegorz; Ko?odziej, Bartosz; Koziolek, Mirko; Weitschies, Werner; Klein, Sandra

2013-06-01

11

Radiolysis of aqueous solutions of ammonium bicarbonate over a large dose range  

NASA Astrophysics Data System (ADS)

Oxygen-free aqueous solutions of 0.05 mol dm -3 ammonium and sodium bicarbonate were studied after receiving various doses of 60Co gammas (0.01-400 kGy) or 0.5-20 Gy pulses of 10 Mev electrons. Formate and oxalate were found to be the main radiolytic products, in addition to trace amounts of formaldehyde and an unidentified polymer. A large initial yield of formate in the ?-radiolysis, G( HCOO-)=2.2, is due to the reaction COO - + HCO -3?HCOO -+CO -3. The efficiency of organic synthesis within the large dose range studied is low and is explained by efficient pathways leading to the reformation of bicarbonate, where the reaction COO -+CO -3 is particularly significant. Computer fitting of the data obtained gives k(COO - + HCO -3)=(2±0.4) x 10 3 dm 3 mol -1 s -1, k(COO -+CO -3) = (5±1) x 10 7 dm 3 mol -1 s -1, k(NH 2+HCO -3)< 10 4 dm 3 mol -1 s -1, and k(NH 2+CO -3) = (1.5±0.5) x 10 9 dm 3 mol -1 s -1.

Dragani?, Z. D.; Negrón-Mendoza, A.; Sehested, K.; Vujoševi?, S. I.; Navarro-Gonzáles, R.; Albarrán-Sanchez, M. G.; Dragani?, I. G.

12

Bicarbonate buffered ultrafiltration leads to a physiologic priming solution in pediatric cardiac surgery.  

PubMed

Pediatric cardiopulmonary bypass (CPB) involves a high ratio of priming blood volume to patient blood volume. The composition of packed red blood cells (RBCs) is very unphysiological in terms of acid-base, electrolyte and metabolite values. Therefore, we tested the hypothesis whether ultrafiltration of the prime and replacement with bicarbonate buffered hemofiltration solution (BB-HS) is sufficient for reducing the metabolic load and reaching a physiologic state. For planned surgery of congenital heart defects with cardiopulmonary bypass, 20 CPB circuits were primed with BB-HS, gelatin and 1 unit of RBCs. The fluid was hemofiltrated using an ultrahemofilter at 300 ml/min until approximately 1000 ml of ultrafiltrate was restored with BB-HS. Blood gas analyses were obtained from the priming blood, once before and once after bicarbonate buffered ultrafiltration (BBUF). The measured substrates decreased significantly (P<0.001) after BBUF (glucose from 13.0+/-2.6 to 6.3+/-1.0 and lactate from 3.8+/-1.5 to 2.3+/-1.0 mmol/l). Acid-base parameters increased (P<0.001) to normal or high normal values (pH from 7.01+/-0.09 to 7.68+/-0.12; HCO(3) from 12.1+/-2.4 to 25.4+/-3.6 mmol/l and BE from -15.4+/-3.6 to -0.8+/-3.7 mmol/l). Even the electrolytes sodium, potassium and calcium changed significantly (P<0.001) toward the physiologic range. BBUF is an efficient method of reducing the metabolic load of priming. After BBUF, even the electrolyte and acid-base balance reached a physiologic state, which is important for minimizing electrolyte and acid-base disturbances after initiation of CPB. PMID:18718953

Osthaus, Wilhelm Alexander; Sievers, Jan; Breymann, Thomas; Suempelmann, Robert

2008-12-01

13

Evolution of a physiological pH 6.8 bicarbonate buffer system: Application to the dissolution testing of enteric coated products  

Microsoft Academic Search

The use of compendial pH6.8 phosphate buffer to assess dissolution of enteric coated products gives rise to poor in vitro–in vivo correlations because of the inadequacy of the buffer to resemble small intestinal fluids. A more representative and physiological medium, pH6.8 bicarbonate buffer, was developed to evaluate the dissolution behaviour of enteric coatings. The bicarbonate system was evolved from pH7.4

Fang Liu; Hamid A. Merchant; Rucha P. Kulkarni; Maram Alkademi; Abdul W. Basit

2011-01-01

14

In vitro effects of bicarbonate and bicarbonate-lactate buffered peritoneal dialysis solutions on mesothelial and neutrophil function.  

PubMed

The inclusion of bicarbonate in the formulation of peritoneal dialysis solutions may avoid the in vitro impairment of certain cell functions seen with acidic lactate-based fluids. The supranormal physiological levels of HCO3- and PCO2 inherent in such formulations may, however, not be biocompatible. This study compared the in vitro biocompatibility of a pH 5.2 lactate-based formulation with formulations containing either 40 mM lactate at pH 7.4, 38 mM HCO3- at pH 6.8 (PCO2 at approximately 240 mm Hg) or 7.4 (PCO2 at approximately 60 mm Hg), and 25 mM HCO3- plus 15 mM lactate at pH 6.8 (PCO2 at approximately 160 mm Hg) or 7.4 (PCO2 at approximately 40 mm Hg). Significant release of lactate dehydrogenase or decreases in ATP content by human peritoneal mesothelial cells (HPMC) and human peripheral polymorphonuclear leukocytes (PMN) after a 30-min exposure to each test solution was only seen with the pH 5.2 lactate-based fluid. The ATP content of HPMC exposed to this fluid returned to control levels after 30 min of recovery in M199 control medium but showed a trend toward decreasing ATP content at 240 min. Similarly, interleukin (IL)-1 beta-induced IL-6 synthesis by HPMC was also only significantly reduced by the pH 5.2 lactate solution. PMN chemiluminescence was unaffected by 30-min exposure to all test solutions except for the pH 5.2 lactate formulation. Staphylococcus epidermidis phagocytosis was reduced to between 46 to 57% of control with all test solutions except the pH 5.2 lactate solution, which further suppressed the chemiluminescence response to 17% of control. These data suggest that short exposure to supranormal physiological levels of HCO3- and PCO2 does not impair HPMC or PMN viability and function. Furthermore, neutral pH lactate-containing solutions show equivalent biocompatibility to bicarbonate-based ones. PMID:8785390

Topley, N; Kaur, D; Petersen, M M; Jörres, A; Williams, J D; Faict, D; Holmes, C J

1996-02-01

15

Evolution of a physiological pH 6.8 bicarbonate buffer system: application to the dissolution testing of enteric coated products.  

PubMed

The use of compendial pH 6.8 phosphate buffer to assess dissolution of enteric coated products gives rise to poor in vitro-in vivo correlations because of the inadequacy of the buffer to resemble small intestinal fluids. A more representative and physiological medium, pH 6.8 bicarbonate buffer, was developed to evaluate the dissolution behaviour of enteric coatings. The bicarbonate system was evolved from pH7.4 Hanks balanced salt solution to produce a pH 6.8 bicarbonate buffer (modified Hanks buffer, mHanks), which resembles the ionic composition and buffer capacity of intestinal milieu. Prednisolone tablets were coated with a range of enteric polymers: hypromellose phthalate (HP-50 and HP-55), cellulose acetate phthalate (CAP), hypromellose acetate succinate (HPMCAS-LF and HPMCAS-MF), methacrylic acid copolymers (EUDRAGIT® L100-55, EUDRAGIT® L30D-55 and EUDRAGIT® L100) and polyvinyl acetate phthalate (PVAP). Dissolution of coated tablets was carried out using USP-II apparatus in 0.1M HCl for 2h followed by pH 6.8 phosphate buffer or pH 6.8 mHanks bicarbonate buffer. In pH 6.8 phosphate buffer, the various enteric polymer coated products displayed rapid and comparable dissolution profiles. In pH 6.8 mHanks buffer, drug release was delayed and marked differences were observed between the various coated tablets, which is comparable to the delayed disintegration times reported in the literature for enteric coated products in the human small intestine. In summary, the use of pH 6.8 physiological bicarbonate buffer (mHanks) provides more realistic and discriminative in vitro release assessment of enteric coated formulations compared to compendial phosphate buffer. PMID:21255647

Liu, Fang; Merchant, Hamid A; Kulkarni, Rucha P; Alkademi, Maram; Basit, Abdul W

2011-05-01

16

Better preservation of peritoneal morphologic features and defense in rats after long-term exposure to a bicarbonate/lactate-buffered solution.  

PubMed

The long-term effects of a standard lactate-buffered dialysis fluid and a new, two-chamber, bicarbonate/lactate-buffered dialysis fluid (with fewer glucose degradation products and a neutral pH) were compared in an in vivo peritoneal exposure model. Rats were given daily injections, via an access port, of 10 ml of standard solution or bicarbonate/lactate-buffered solution for 9 to 10 wk. The omentum, peritoneum, and mesothelial cell layer were screened for morphologic changes. In addition, the bacterial clearing capacity of the peritoneal cells was studied. Significantly more milky spots and blood vessels were observed in the omenta of animals treated with standard solution (P < 0.03 for both parameters). Electron-microscopic analysis demonstrated dramatic changes in the appearance of the vascular endothelial cells of the milky spots and a severely damaged or even absent mesothelium on the peritoneal membrane of the standard solution-treated animals. In contrast, the mesothelium was still present in the bicarbonate/lactate-buffered solution group, although the cells lost microvilli. Both peritoneal dialysis fluids significantly increased the density of mesothelial cells (per square millimeter) on the surface of the liver and the thickness of the submesothelial extracellular matrix of the peritoneum (both P < 0.04 for both fluids versus control). A significantly better ex vivo bacterial clearing capacity was observed with peritoneal cells from the bicarbonate/lactate-buffered solution group, compared with the standard solution group (P < 0.05 in both experiments). These results demonstrate that instillation of bicarbonate/lactate-buffered solution into rats for 9 to 10 wk preserves both morphologic and immune parameters much more effectively, compared with standard solution. These findings may be of considerable clinical importance. PMID:11729248

Hekking, L H; Zareie, M; Driesprong, B A; Faict, D; Welten, A G; de Greeuw, I; Schadee-Eestermans, I L; Havenith, C E; van den Born, J; ter Wee, P M; Beelen, R H

2001-12-01

17

Population analysis of mesothelium in situ and in vivo exposed to bicarbonate-buffered peritoneal dialysis fluid.  

PubMed

Population analysis of mesothelium (PAM) done using the in vivo and almost in situ technique of mesothelial cell imprints revealed that lactate-buffered solutions had detrimental effects upon cell viability, that high glucose concentration affected cytokinesis, whereas the association of both components led to a decreased density population of cells showing a larger surface area. In the present study, PAM was done on mesothelium of mice exposed to bicarbonate-buffered peritoneal dialysis fluid (BBF) with glucose concentrations of 1.5 and 4.25%, for periods of time of 2 h, 15 and 30 days, as well as after recovery intervals of 7 and 30 days, BBF did not affect mesothelial cell viability. However, the increased incidence of multinucleated cells observed with both glucose concentrations, more marked with the 4.25% solution, suggests a detrimental effect upon the mechanism of cytokinesis. Furthermore, the higher the glucose concentration, the higher the mean-cell cytoplasmic surface area and the proportion of large cells, both resulting most probably from the regulatory volume increase developed by cells continuously exposed to hyperosmolar fluids. So far, evidence presented in this study suggests once more that BBF is remarkably more compatible with a higher quality of adaptation and survival of the exposed mesothelium than the lactated fluid. The question of whether the alterations induced by the high concentration of glucose result from a specific effect of glucose, by the coincidental hyperosmolarity, or by both still remains unanswered. PMID:8773348

Gotloib, L; Wajsbrot, V; Shostak, A; Kushnier, R

1996-01-01

18

Coral reef calcifiers buffer their response to ocean acidification using both bicarbonate and carbonate  

PubMed Central

Central to evaluating the effects of ocean acidification (OA) on coral reefs is understanding how calcification is affected by the dissolution of CO2 in sea water, which causes declines in carbonate ion concentration [CO32?] and increases in bicarbonate ion concentration [HCO3?]. To address this topic, we manipulated [CO32?] and [HCO3?] to test the effects on calcification of the coral Porites rus and the alga Hydrolithon onkodes, measured from the start to the end of a 15-day incubation, as well as in the day and night. [CO32?] played a significant role in light and dark calcification of P. rus, whereas [HCO3?] mainly affected calcification in the light. Both [CO32?] and [HCO3?] had a significant effect on the calcification of H. onkodes, but the strongest relationship was found with [CO32?]. Our results show that the negative effect of declining [CO32?] on the calcification of corals and algae can be partly mitigated by the use of HCO3? for calcification and perhaps photosynthesis. These results add empirical support to two conceptual models that can form a template for further research to account for the calcification response of corals and crustose coralline algae to OA.

Comeau, S.; Carpenter, R. C.; Edmunds, P. J.

2013-01-01

19

A Prospective, Randomized, Double-Blind Study of the Anesthetic Efficacy of Sodium Bicarbonate Buffered 2% Lidocaine With 1 : 100,000 Epinephrine in Inferior Alveolar Nerve Blocks  

PubMed Central

Abstract The authors, using a crossover design, randomly administered, in a double-blind manner, inferior alveolar nerve (IAN) blocks using a buffered 2% lidocaine with 1?:?100,000 epinephrine/sodium bicarbonate formulation and an unbuffered 2% lidocaine with 1?:?100,000 epinephrine formulation at 2 separate appointments spaced at least 1 week apart. An electric pulp tester was used in 4-minute cycles for 60 minutes to test for anesthesia of the first and second molars, premolars, and lateral and central incisors. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes, and the 80 reading was continuously sustained for 60 minutes. For the buffered 2% lidocaine with 1?:?100,000 epinephrine/sodium bicarbonate formulation, successful pulpal anesthesia ranged from 10–71%. For the unbuffered 2% lidocaine with 1?:?100,000 epinephrine formulation, successful pulpal anesthesia ranged from 10–72%. No significant differences between the 2 anesthetic formulations were noted. The buffered lidocaine formulation did not statistically result in faster onset of pulpal anesthesia or less pain during injection than did the unbuffered lidocaine formulation. We concluded that buffering a 2% lidocaine with 1?:?100,000 epinephrine with sodium bicarbonate, as was formulated in the current study, did not statistically increase anesthetic success, provide faster onset, or result in less pain of injection when compared with unbuffered 2% lidocaine with 1?:?100,000 epinephrine for an IAN block.

Whitcomb, Michael; Drum, Melissa; Reader, Al; Nusstein, John; Beck, Mike

2010-01-01

20

Accelerating the dissolution of enteric coatings in the upper small intestine: Evolution of a novel pH 5.6 bicarbonate buffer system to assess drug release.  

PubMed

Despite rapid dissolution in compendial phosphate buffers, gastro resistant (enteric coated) products can take up to 2h to disintegrate in the human small intestine, which clearly highlights the inadequacy of the in vitro test method to predict in vivo behaviour of these formulations. The aim of this study was to establish the utility of a novel pH 5.6 bicarbonate buffer, stabilized by an Auto pH™ System, as a better surrogate of the conditions of the proximal small intestine to investigate the dissolution behaviour of standard and accelerated release enteric double coating formulations. Prednisolone tablets were coated with 3 or 5mg/cm(2) of partially neutralized EUDRAGIT(®) L 30 D-55, HP-55 or HPMC adjusted to pH 6 or 8. An outer layer of EUDRAGIT(®) L 30 D-55 was applied at 5mg/cm(2). For comparison purposes, a standard single layer of EUDRAGIT(®) L 30 D-55 was applied to the tablets. Dissolution was carried out using USP II apparatus in 0.1M HCl for 2h, followed by pH 5.6 bicarbonate buffer. EUDRAGIT(®) L 30 D-55 single-coated tablets showed a slow drug release with a lag time of 75min in buffer, whereas release from the EUDRAGIT(®) L 30 D-55 double-coated tablets was accelerated. These in vitro lag times closely match the in vivo disintegration times for these coated tablets reported previously. Drug release was further accelerated from modified double coatings, particularly in the case of coatings with a thinner inner layer of HP-55 or HPMC (pH 8 and KH2PO4). This study confirms that the pH 5.6 bicarbonate buffer system offers significant advantages during the development of dosage forms designed to release the drug in the upper small intestine. PMID:24727141

Varum, Felipe J O; Merchant, Hamid A; Goyanes, Alvaro; Assi, Pardis; Zboranová, Veronika; Basit, Abdul W

2014-07-01

21

Continuous dialysis with bicarbonate/lactate-buffered peritoneal dialysis fluids results in a long-term improvement in ex vivo peritoneal macrophage function.  

PubMed

To circumvent the potentially negative consequences of long-term exposure to unphysiologic acidic lactate-buffered peritoneal dialysis fluids (PDF), neutral pH solutions buffered with bicarbonate/lactate have recently been introduced in phase 2 and 3 clinical trials. This study examines the longitudinal changes in peritoneal macrophage (PMØ) function in patients dialyzed continuously with either lactate (LPD; 40 mM lactate, pH 5.2)-buffered or bicarbonate/lactate (TBL; 25 mM/15 mM bicarbonate/lactate, pH 7.3)-buffered PDF. Before the study, during the run in period of a phase 3 clinical trial, all patients had been taking LPD for at least the previous 18 wk. At the beginning of the study (day 0), both constitutive and serum-treated zymosan (STZ) stimulated tumor necrosis factor alpha (TNF-alpha) synthesis were assessed in PMØ isolated from 12-h dwell effluent (with 1.36% glucose) in all patients. The patients were subsequently randomized to either continuous TBL or LPD therapy and PMØ function was assessed after further 3- and 6-mo periods in all patients. At all time points measured STZ induced a dose-dependent increase in PMØ TNF-alpha secretion (P = 0.043 versus control for doses greater than 100 microg/ml). In patients continuously dialyzed with LPD, constitutive PMØ TNF-alpha synthesis levels (mean +/- SEM, pg/10(6) PMØ per18 h, n = 5 patients) were 154 +/- 65, 261 +/- 60, and 101 +/- 99 at 0, 3, and 6 mo, respectively. Stimulated STZ (1000 microg/ml) levels were 1340 +/- 519, 1046 +/- 586, and 758 +/- 250 at 0, 3, and 6 mo, respectively. In patients dialyzed with TBL, constitutive PMØ TNF-alpha synthesis levels (pg/10(6) PMØ per 18 h, n = 5 patients) were 300 +/- 136, 106 +/- 35, and 213 +/- 62 at 0, 3, and 6 mo, respectively. Stimulated STZ (1000 microg/ml) levels were 1969 +/- 751, 1541 +/- 330, and 2670 +/- 671 at 0, 3, and 6 mo, respectively. At 6 mo, STZ-stimulated PMØ TNF-alpha synthesis was significantly higher in patients treated with TBL compared with those treated with LPD (P = 0.0035). These data suggest that in patients continuously dialyzed with a neutral pH solution, there is a long-term improvement in PMØ function compared with patients on conventional therapy. Better PMØ function suggests improved host defense status and may affect the peritoneum's susceptibility to infection and potentially reduce the negative consequences of repeated intraperitoneal inflammation on long-term membrane function. PMID:11792769

Jones, Suzanne; Holmes, Clifford J; Mackenzie, Ruth K; Stead, Rachel; Coles, Gerald A; Williams, John D; Faict, Dirk; Topley, Nicholas

2002-01-01

22

Method of uranium reclamation from aqueous systems by reactive ion exchange. [US DOE patent application; anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands  

Microsoft Academic Search

A reactive ion exchange method for separation and recovery of values of uranium, neptunium, plutonium, or americium from substantially neutral aqueous systems of said metals comprises contacting said system with an effective amount of a basic anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands to achieve nearly 100% sorption of said actinyl ion

1981-01-01

23

Comparative anti-ulcerogenic study of pantoprazole formulation with and without sodium bicarbonate buffer on pyloric ligated rat  

PubMed Central

Objective: To compare the anti-ulcer activity of buffered pantoprazole tablet against plain pantoprazole in pyloric ligated rats. Materials and Methods: In vivo pyloric ligated ulcerogenesis model was used to assess the effect of buffered pantoprazole on the volume of the gastric content, pH, total and free acidity, and ulcerogenic lesion. Pantoprazole level in gastric content and concurrently in stomach tissue was assessed by High Performance Liquid Chromatography (HPLC) analysis. Results: Buffered tablet effectively increases the pH of the gastric content above 4 up to 6 h (P<0.001) protecting pantoprazole from acid degradation resulting in high concentration in the gastric content and stomach tissue. Conclusions: This study substantiates better, faster and prolonged bioavailability of pantoprazole-buffered tablet compared to plain pantoprazole.

Bigoniya, Papiya; Shukla, A.; Singh, C. S.; Gotiya, P.

2011-01-01

24

Internal Active Thermal Control System (IATCS) Sodium Bicarbonate/Carbonate Buffer in an Open Aqueous Carbon Dioxide System and Corollary Electrochemical/Chemical Reactions Relative to System pH Changes  

NASA Technical Reports Server (NTRS)

The International Space Station (ISS) Internal Active Thermal Control System (IATCS) experienced a number of chemical changes driven by system absorption of CO2 which altered the coolant’s pH. The natural effects of the decrease in pH from approximately 9.2 to less than 8.4 had immediate consequences on system corrosion rates and corrosion product interactions with specified coolant constituents. The alkalinity of the system was increased through the development and implementation of a carbonate/bicarbonate buffer that would increase coolant pH to 9.0 – 10.0 and maintain pH above 9.0 in the presence of ISS cabin concentrations of CO2 up to twenty times higher than ground concentrations. This paper defines how a carbonate/bicarbonate buffer works in an open carbon dioxide system and summarizes the analyses performed on the buffer for safe and effective application in the on-orbit system. The importance of the relationship between the cabin environment and the IATCS is demonstrated as the dominant factor in understanding the system chemistry and pH trends before and after addition of the carbonate/bicarbonate buffer. The paper also documents the corollary electrochemical and chemical reactions the system has experienced and the rationale for remediation of these effects with the addition of the carbonate/bicarbonate buffer.

Stegman, Thomas W.; Wilson, Mark E.; Glasscock, Brad; Holt, Mike

2014-01-01

25

Dialysis solutions buffered with lactate or bicarbonate: in vitro comparison of two dialysis solutions on human peritoneal cell growth from ESRD and non-ESRD patients.  

PubMed

In order to evaluate the injury to the mesothelial cell layer during long-term peritoneal dialysis (PD), a dialysis solution (solution A), buffered with bicarbonate, stabilized with 10 mmol/L glycylglycine, and sterilized by filtration (0.22 micron double filtration, pH = 7.4), was compared to traditional heat sterilized lactate solution (solution B) on human mesothelial cell cultures. The respective effects of both solutions were evaluated on first passage cells by 3H thymidine incorporation after 72-, 96-, 120-, and 144-h contact. Mesothelial cells to be cultured were obtained from the omentum biopsies of 7 end-stage renal disease (ESRD) patients (during first peritoneal catheter placement) and from 7 non-ESRD patients undergoing abdominal surgery. Solution A (diluted 1/5) induced a time-dependent stimulation of growth in 6 cases of ESRD patient cell cultures, and inhibition occurred only in 1 case. Stimulation was also observed in 5 non-ESRD patient cell cultures, and no effect occurred in 2 cases. Solution B inhibited growth in all the cultures except in 1 case of an ESRD patient in which no effect was observed. This study shows that solution A induced mesothelial cell proliferation, while an inhibitory effect of solution B was observed. No significant differences were observed between the sensitivity of mesothelial cells from ESRD and non-ESRD patients. Further analysis will be carried out to identify precisely the cause of the differences observed: buffer or glycylglycine by themselves and/or glucose by-products. PMID:7999836

Fougeray, S; Slingeneyer, A; Bastide, J M; Mion, C; Bastide, M

1994-01-01

26

Effect of two-chambered bicarbonate lactate-buffered peritoneal dialysis fluids on peripheral blood mononuclear cell and polymorphonuclear cell function in vitro.  

PubMed

Low pH, high osmolality, increasing glucose concentration, and glucose degradation products (GDP) formed during heat sterilization of conventional peritoneal dialysis (PD) fluids have been shown to have a detrimental effect on cells involved in peritoneal host defense. The two-chambered PD fluid bag in which glucose at pH approximately 3 is separated from a bicarbonate (25 mmol/L)-lactate (15 mmol/L) buffer during heat sterilization permits PD fluids with lower GDP to be delivered to the patient at neutral pH. To establish the possible benefit of two-chambered bag PD fluids on peripheral blood mononuclear cell (PBMC) and polymorphonuclear (PMN) cell function, we compared conventional 1.5% Dianeal (1.5%D) with 1.5% two-chambered bag bicarbonate-lactate (1.5%D-B), and conventional 4.25% Dianeal (4.25%D) with 4.25% two-chambered bag bicarbonate-lactate (4.25%D-B). Furthermore, to study the effect of the sterilization process on PBMC and PMN function, we compared filter-sterilized 4.25%D (4.25%D-F) with 4.25%D and 4.25%D-B. PBMC were harvested by Ficoll-Hypaque separation, and 2.5 x 10(6) cells in RPMI were incubated with an equal volume of the test fluids for 4 hours, pelleted, and resuspended in RPMI containing 10 ng endotoxin for a further 20 hours. Tumor necrosis factor alpha (TNF-alpha) production by endotoxin-stimulated PBMC was not significantly different (P = 0.10) between 1.5%D-B and 1.5%D, but was significantly higher (P = 0.01) with 4.25%D-B compared with 4.25%D. PBMC exposed to filter-sterilized fluid (4.25%D-F) showed significantly higher endotoxin-stimulated TNF-alpha production compared with 4.25%D (P = 0.02), but was not significantly different from 4.25%D-B (P = 0.40). PMN were harvested by Ficoll-Hypaque separation and 10 x 10(6) cells incubated with test fluids for 30 minutes. After incubation, phagocytosis (phagocytosis index) was determined by the uptake of 14C-labeled Staphylococcus aureus, oxidative burst by reduction of ferricytochrome C to ferrocytochrome C on stimulation with PMA, and enzyme release by measurement of endotoxin-stimulated bactericidal/permeability increasing protein (BPI). Bicarbonate-lactate two-chambered fluids of similar osmolality and glucose concentration conferred a significant improvement in phagocytosis (P = 0.02 for 1.5%D-B and P < 0.001 for 4.25%D-B). Oxidative burst and BPI release were significantly higher in 4.25%D-B compared with 4.25%D (P < 0.001). Filter-sterilized 4.25%D-F conferred a significant improvement in phagocytosis and oxidative burst compared with 4.25%D (P < 0.001) or 4.25%D-B (P < 0.001). Furthermore, conventional 4.25%D was associated with significantly lower BPI release compared with 4.25%D-F (P = 0.01). GDP's acetaldehyde and 5-HMF were analyzed in 4.25%D-B, 4.25%D, and 4.25%D-F. Acetaldehyde was below the lower limit (0.79 ppm) of the standard curve in 4.25%D-B and 4.25%D-F fluids but was detected (3.76 to 5.12 ppm) in all of the 4.25%D fluids. Relative levels of 5-HMF in the 4.25%D-B (0.032 to 0.041 Abs @ 284 nm) and 4.25%D (0.031 to 0.036 Abs @ 284 nm) were similar. The lowest levels (0.001 Abs @ 284 nm) were observed in the filter-sterilized 4.25%D-F. The beneficial effects of two-chambered bicarbonate lactate-buffered PD fluids on PBMC and PMN function are probably related to reduction of GDP from heat sterilization of glucose in a separate chamber at a lower pH. This improvement in biocompatibility could have a beneficial affect on peritoneal defenses. PMID:9370184

Sundaram, S; Cendoroglo, M; Cooker, L A; Jaber, B L; Faict, D; Holmes, C J; Pereira, B J

1997-11-01

27

Bicarbonate Test  

MedlinePLUS

... CO 2 Content; Bicarb; HCO 3 - Formal name: Bicarbonate Related tests: Electrolytes ; Sodium ; Potassium ; Chloride ; CMP ; BMP ; Blood Gases Total CO 2 or bicarbonate is different than the partial pressure of CO ...

28

Evaluation of stainless steel cathodes and a bicarbonate buffer for hydrogen production in microbial electrolysis cells using a new method for measuring gas production  

Microsoft Academic Search

Microbial electrolysis cells (MECs) are often examined for hydrogen production using non-sustainable phosphate buffered solutions (PBS), although carbonate buffers have been shown to work in other bioelectrochemical systems with a platinum (Pt) catalyst. Stainless steel (SS) has been shown to be an effective catalyst for hydrogen evolution in MECs, but it has not been tested with carbonate buffers. We evaluated

Jack R. Ambler; Bruce E. Logan

2011-01-01

29

Method of uranium reclamation from aqueous systems by reactive ion exchange. [US DOE patent application; anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands  

DOEpatents

A reactive ion exchange method for separation and recovery of values of uranium, neptunium, plutonium, or americium from substantially neutral aqueous systems of said metals comprises contacting said system with an effective amount of a basic anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands to achieve nearly 100% sorption of said actinyl ion onto said resin and an aqueous system practically free of said actinyl ions. The method is operational over an extensive range of concentrations from about 10/sup -6/ M to 1.0 M actinyl ion and a pH range of about 4 to 7. The method has particulr application to treatment of waste streams from Purex-type nuclear fuel reprocessing facilities and hydrometallurgical processes involving U, Np, P, or Am.

Maya, L.

1981-11-05

30

The molecular mechanism of neural induction: neural differentiation of Triturus ectoderm exposed to Hepes buffer  

Microsoft Academic Search

Ectoderm was isolated from early gastrula stages of Triturus alpestris and cultured in salt solution buffered with either bicarbonate or Hepes as the principal buffer substance. When bicarbonate was the principal buffer substance or when bicarbonate was omitted, the isolated ectoderm formed atypical epidermis. When Hepes was added as a buffer substance, neural tissue was formed in a high percentage

Hildegard Tiedemann

1986-01-01

31

21 CFR 184.1137 - Ammonium carbonate.  

Code of Federal Regulations, 2013 CFR

...NH4 )2 CO3 , CAS Reg. No. 8000-73-5) is a mixture of ammonium bicarbonate (NH4 HCO3 ) and ammonium carbamate (NH2 COONH4 ). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and...

2013-04-01

32

Internal acid buffering in San Joaquin Valley fog drops and its influence on aerosol processing  

NASA Astrophysics Data System (ADS)

Although several chemical pathways exist for S(IV) oxidation in fogs and clouds, many are self-limiting: as sulfuric acid is produced and the drop pH declines, the rates of these pathways also decline. Some of the acid that is produced can be buffered by uptake of gaseous ammonia. Additional internal buffering can result from protonation of weak and strong bases present in solution. Acid titrations of high pH fog samples (median pH=6.49) collected in California's San Joaquin Valley reveal the presence of considerable internal acid buffering. In samples collected at a rural location, the observed internal buffering could be nearly accounted for based on concentrations of ammonia and bicarbonate present in solution. In samples collected in the cities of Fresno and Bakersfield, however, significant additional, unexplained buffering was present over a pH range extending from approximately four to seven. The additional buffering was found to be associated with dissolved compounds in the fogwater. It could not be accounted for by measured concentrations of low molecular weight ( C1- C3) carboxylic acids, S(IV), phosphate, or nitrophenols. The amount of unexplained buffering in individual fog samples was found to correlate strongly with the sum of sample acetate and formate concentrations, suggesting that unmeasured organic species may be important contributors. Simulation of a Bakersfield fog episode with and without the additional, unexplained buffering revealed a significant impact on the fog chemistry. When the additional buffering was included, the simulated fog pH remained 0.3-0.7 pH units higher and the amount of sulfate present after the fog evaporated was increased by 50%. Including the additional buffering in the model simulation did not affect fogwater nitrate concentrations and was found to slightly decrease ammonium concentrations. The magnitude of the buffering effect on aqueous sulfate production is sensitive to the amount of ozone present to oxidize S(IV) in these high pH fogs.

Collett, Jeffrey L.; Hoag, Katherine J.; Rao, Xin; Pandis, Spyros N.

33

Addition of Sodium Bicarbonate to Rations of Pre and Postpartum Dairy Cows1  

Microsoft Academic Search

Sodium bicarbonate was added to complete mixed rations to evaluate the effect of buffer addition on adaptation to high-energy rations by dairy cows in early lactation. Forty-five Holstein cows were assigned to one of three treatment groups: control pre- and postpartum; control prepartum, buffer postpartum; and buffer pre- and postpartum. Rations consisted of 85% chopped grass hay: 15% concentrate prepartum

L. H. Kilmer; L. D. Muller; P. J. Wangsness

1980-01-01

34

DIETHANOLAMINE-CARBON DIOXIDE BUFFER PRODUCES ETHYLENE  

EPA Science Inventory

Carbon dioxide concentrates in containers are frequently controlled by using a diethanolamine-bicarbonate buffer. Current studies show that this buffer produces ethylene and that the production increases with increasing pH and/or time in the incubation vessel. Ethylene is not pro...

35

Addition of Sodium Bicarbonate to Rations of Postpartum Dairy Cows: Physiological and Metabolic Effects1  

Microsoft Academic Search

Sodium bicarbonate was added to complete mixed rations to characterize physiological, metabolic, and ruminal changes immediately postpartum when dairy cows are switched abruptly from a low energy ration prepartum to a high energy ration postpartum. Twelve Holstein cows were paired and assigned randomly to either a control or buffered ration containing .8% sodium bicarbonate. Ra- tions consisted of 50% corn

L. H. Kilmer; L. D. Muller; T. J. Snyder

1981-01-01

36

Bicarbonate\\/lactate-based peritoneal dialysis solution increases cancer antigen 125 and decreases hyaluronic acid levels  

Microsoft Academic Search

Bicarbonate\\/lactate peritoneal dialysate increases cancer antigen 125 and decreases hyaluronic acid levels.BackgroundIn a randomized, controlled trial comparing a pH neutral, bicarbonate\\/lactate (B\\/L)-buffered PD solution to conventional acidic, lactate-buffered solution (C), the overnight dialysate levels of markers of inflammation\\/wound healing [hyaluronic acid (HA)], mesothelial cell mass\\/membrane integrity [cancer antigen 125 (CA125)], and fibrosis [transforming growth factor-?1 (TGF-?1) and procollagen I peptides

Suzanne Jones; Clifford J. Holmes; Raymond T. Krediet; Ruth Mackenzie; Dirk Faict; Anders Tranaeus; John D. Williams; Gerald A. Coles; Nicholas Topley

2001-01-01

37

Reaction of reductively activated mitomycin C with aqueous bicarbonate: Isolation and characterization of an oxazolidinone derivative of cis-1-hydroxy-2,7-diaminomitosene.  

PubMed

The reductive activation of mitomycin C in aqueous bicarbonate buffer resulted in the formation of a previously unknown compound, characterized as an oxazolidinone derivative of cis-1-hydroxy-2,7-diaminomitosene. This compound is the result of a cyclization reaction of bicarbonate with the aziridine ring of aziridinomitosene, and was observed at bicarbonate concentrations close to those present in physiological plasma. PMID:19954979

Paz, Manuel M

2010-01-01

38

Aldosterone Deficiency and Renal Bicarbonate Reabsorption.  

National Technical Information Service (NTIS)

Selective aldosterone deficiency was induced in 16 dogs. All of these animals developed hyperkalemic metabolic acidosis. Bicarbonate reabsorption was measured in these animals. At low plasma bicarbonate concentrations (15 to 24 mEq. per liter) bicarbonate...

M. G. White N. A. Kurtzman P. M. Meserol P. W. W. Rogers

1971-01-01

39

Attractiveness to mexican fruit flies of combinations of acetic acid with ammonium\\/amino attractants with emphasis on effects of hunger  

Microsoft Academic Search

Ammonium acetate was more attractive than other ammonium salts to Mexican fruit flies (Anastrepha ludens) in an orchard test. We hypothesized that acetic acid enhanced the attractiveness of ammonia in the orchard test and that acetic acid may similarly enhance attractiveness of AMPu, an attractant consisting of a mixture of ammonium bicarbonate or ammonium carbonate, methylamine HCl, and putrescine. In

D. C. Robacker; D. S. Moreno; A. B. Demilo

1996-01-01

40

Studies on bicarbonate transporters and carbonic anhydrase in porcine non-pigmented ciliary epithelium  

PubMed Central

Purpose Bicarbonate transport plays a role in aqueous humor (AH) secretion. Here, we examined bicarbonate transport mechanisms and carbonic anhydrase (CA) in porcine non-pigmented ciliary epithelium (NPE). Methods Cytoplasmic pH (pHi) was measured in cultured porcine NPE loaded with BCECF. Anion exchanger (AE), sodium bicarbonate cotransporter (NBC) and CA were examined by RT-PCR and immunolocalization. AH secretion was measured in the intact porcine eye using a fluorescein dilution technique. Results Anion exchanger AE2, CAII and CAIV were abundant in the NPE layer. In cultured NPE superfused with a CO2/HCO3? free HEPES buffer, exposure to a CO2/HCO3?-containing buffer caused a rapid acidification followed by a gradual pHi increase. Subsequent removal of CO2/HCO3? with HEPES buffer caused rapid alkalinization followed by gradual pHi decrease. The rate of gradual alkalinization after addition of HCO3?/CO2 was inhibited by sodium-free conditions, DIDS, CA inhibitors acetazolamide and methazolamide but not by Na-H exchange inhibitor dimethylamiloride or low chloride buffer. The phase of gradual acidification after removal of HCO3?/CO2 was inhibited by DIDS, acetazolamide, methazolamide and by low chloride buffer. DIDS reduced baseline pHi. In the intact eye, DIDS and acetazolamide reduced AH secretion by 25% and 44% respectively. Conclusion The results suggest the NPE uses a Na+-HCO3? cotransporter to import bicarbonate and a Cl?/HCO3? exchanger to export bicarbonate. CA influences the rate of bicarbonate transport. AE2, CAII and CAIV are enriched in the NPE layer of the ciliary body and their coordinated function may contribute to AH secretion by effecting bicarbonate transport into the eye.

Shahidullah, Mohammad; C-H, To; Pelis, Ryan M.; Delamere, Nicholas A

2009-01-01

41

Chloride and bicarbonate transport in rat resistance arteries.  

PubMed Central

1. The role of chloride and bicarbonate in the control of intracellular pH (pHi) was assessed in segments of rat mesenteric resistance arteries (internal diameter about 200 microns) by measurements of chloride efflux with 36Cl-, of pHi with the pH-sensitive dye 2',7'-bis-(2-carboxyethyl)-5 (and-6)-carboxyfluorescein (BCECF) and of membrane potential with intracellular electrodes. 2. The main questions addressed were whether the previously demonstrated sodium-coupled uptake of bicarbonate in these arteries was also coupled to chloride efflux, and whether sodium-independent Cl(-)-HCO3- exchange was present and played a role in regulation of pHi. 3. The 36Cl- efflux was unaffected by acidification induced by an NH4Cl pre-pulse in the presence as well as in the absence of bicarbonate. This was also true in sodium-free media and in vessels depolarized by high potassium. 4. The membrane potential was unaffected by the acidification associated with wash-out of NH4Cl, and the net acid extrusion during recovery of pHi from the acidification was not affected significantly by depolarization. 5. In the absence of bicarbonate, omission of extracellular chloride caused no change in pHi, but reduced 36Cl- efflux. By contrast, in the presence of bicarbonate, omission of chloride caused an increase in pHi but no change in 36Cl- efflux. Furthermore, the anion transport inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) inhibited the increase in pHi seen in the presence of bicarbonate and reduced the 36Cl- efflux in the presence of bicarbonate. 6. The presence of bicarbonate had no significant effect on the rate of recovery of pHi or the rate of increase of intracellular acid equivalents after an NH4Cl induced alkalinization; also the buffering power was not significantly different in the absence and presence of bicarbonate. Moreover these parameters were not significantly affected by DIDS, although DIDS as previously demonstrated reduced the rate of recovery of pHi from acidification. 7. The membrane potential was not significantly affected by the alkalinization associated with addition of NH4Cl and the rate of recovery of pHi from the alkalinization was not affected by depolarization. 8. The effects of NH4Cl and PCO2 on 36Cl- efflux were complex and could not easily be explained by the changes in pHi.(ABSTRACT TRUNCATED AT 400 WORDS)

Aalkjaer, C; Hughes, A

1991-01-01

42

Bicarbonate exporting transporters in the ovine ruminal epithelium.  

PubMed

In order to stabilize the intraruminal pH, bicarbonate secretion by the ruminal epithelium seems to be an important prerequisite. The present study therefore focussed on the characterization of bicarbonate exporting systems in ruminal epithelial cells. Intracellular pH (pH(i)) was measured spectrofluorometrically in primary cultured ruminal epithelial cells loaded with the pH-sensitive fluorescent dye, 2,7-bis(carboxyethyl)-5(6')-carboxyfluorescein acetomethyl ester. Switching from CO2/HCO3- -buffered to HEPES-buffered solution caused a rapid intracellular alkalinization followed by a counter-regulation towards initial pH(i). The recovery of pH(i) was dependent upon extracellular chloride, but independent of extracellular sodium. Adding 500 microM H2DIDS significantly reduced the increase of pH(i). For further characterization of the bicarbonate exporting systems, we tested the ability to reverse the direction from HCO3- export to import in the absence of sodium and chloride. Under sodium and chloride-free conditions, counter-regulation after CO2-induced pH(i) decrease did not differ from pH(i) recovery in the presence of sodium and chloride. Existence of bicarbonate exporting systems in cultured ruminal epithelial cells and intact ruminal epithelium was verified by reverse transcription polymerase chain reaction (RT-PCR). Using RT-PCR and subsequent sequencing, expression of mRNA encoding for AE2, DRA and PAT1 could be found. Bicarbonate exporting systems could therefore be detected both on the functional and structural level. PMID:15926041

Bilk, S; Huhn, K; Honscha, K U; Pfannkuche, H; Gäbel, G

2005-07-01

43

Buffering the aqueous phase pH in water-in-CO{sub 2} microemulsions  

SciTech Connect

Water-in-oil (w/o) microemulsions have been exploited for use in a wide range of applications, including chemical and enzymatic reactions, protein and metal extraction, and the production of nanoparticles. Microemulsions are attractive systems for studying such applications because they have the ability to function as a universal solvent medium by solubilizing high concentrations of both polar and apolar molecules within their dispersed aqueous and continuous oil phases, respectively. The addition of organic and inorganic buffers to nanometer size water-in-CO{sub 2} microemulsion droplets stabilized by ammonium perfluoropolyether (PFPE-NH{sub 4}) results in an increase in pH from 3 to values of 5--7. The effects of temperature, pressure, buffer type, buffer concentration, ionic strength, and CO{sub 2} solubility on the pH inside water-in-CO{sub 2} microemulsions and on biphasic water-CO{sub 2} systems were measured by the hydrophilic indicator 4-nitrophenyl-2-sulfonate and were predicted accurately with thermodynamic models. In both systems, modest buffer loadings result in a steep pH jump from 2.5 pH units. Further increases in pH require large amounts of base to overcome buffering due to the carbonic acid-bicarbonate equilibrium. A pH approaching neutrality was obtained in w/c microemulsions with approximately 1.5 mol kg{sup {minus}1} NaOH. At high buffer loadings, the effects of temperature and pressure on pH values are negligible.

Holmes, J.D.; Ziegler, K.J.; Audriani, M.; Lee, C.T. Jr.; Bhargava, P.A.; Johnston, K.P. [Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering] [Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering; Steytler, D.C. [Univ. of East Anglia, Norwich (United Kingdom). School of Chemical Sciences] [Univ. of East Anglia, Norwich (United Kingdom). School of Chemical Sciences

1999-07-08

44

pH and Bicarbonate Effects on Mitochondrial Anion Accumulation  

PubMed Central

Mitochondria from rabbit and dog renal cortex were incubated with 1 mM 14C-weak acid anions in media containing low (10 mM) or high (40 mM) concentrations of bicarbonate and the steady-state accumulation of labeled anion in the matrix was measured. In the absence of an energy source, no concentration of 14C-anion in the mitochondrial matrix space was present, but the anion concentration was significantly higher at low- than at high-bicarbonate concentration. Addition of an energy source, usually ascorbate plus tetramethyl-p-phenylenediamine, led to increases in matrix space anion levels and to accentuation of the difference in anion uptake between low- and high-bicarbonate media, so that two to four times as much anion was present at low- than at high-bicarbonate concentrations. The anions affected included substrates for which inner membrane carriers are present in mitochondria, such as citrate, ?-ketoglutarate, malate, and glutamate, as well as substances which diffuse passively across the inner membrane such as acetate and formate. When a nonbicarbonate medium buffered with Hepes was used, pH change did not alter anion uptake although anion concentrations exceeding those in the medium still developed when an energy source was present. The difference in mitochondrial anion accumulation between low- and high-bicarbonate levels diminished with decreasing temperature or with increasing anion concentration in the medium. Estimation of intramitochondrial pH with [14C]5,5-dimethyl-oxazolidine-2,4-dione showed that the pH gradient across the inner mitochondrial membrane was significantly greater with 10 than with 40 mM bicarbonate in the medium. A hypothesis is described that relates this effect of pH and bicarbonate on mitochondrial anion accumulation to the very rapid changes in substrate levels in renal cortex, which develop when acute metabolic acidosis or alkalosis is produced in the intact animal. It is suggested that an abrupt fall in systemic pH and bicarbonate is associated with a shift in substrate in renal cortex out of the cytoplasm and into mitochondria, where some of the added substrate is metabolized. Reduction in the size of the cytoplasmic pool of substrate occurs with relatively little accompanying change in the size of the mitochondrial pool, thus causing a net reduction in the total tissue pool. This mechanism accounts for the reduction in tissue levels of many mitochondrial substrates observed acutely in metabolic acidosis. In metabolic alkalosis, reversal of these effects leads to expansion of the cytoplasmic pool, thereby resulting in the rise in tissue levels of substrates which occurs in this condition.

Simpson, David P.; Hager, Steven R.

1979-01-01

45

Buffer Biology.  

ERIC Educational Resources Information Center

Presents a science experiment in which students test the buffering capacity of household products such as shampoo, hand lotion, fizzies candy, and cola. Lists the standards addressed in this experiment and gives an example of a student lab write-up. (YDS)

Morgan, Kelly

2000-01-01

46

Effect of Dietary Sodium Bicarbonate and Magnesium Oxide on Production and Physiology in Early Lactation1  

Microsoft Academic Search

Twenty cows were in an experiment to measure effects of dietary buffers, sodium bicarbonate and magnesium oxide, on ration adjustment and incidence of metabolic problems in the first 8 wk postpartum. Cows were fed 2.7 kg grain per day and alfalfa ad libitum prepartum and switched immediately to a complete ration of 40% corn silage and 60% con- centrate (dry

R. A. Erdman; R. L. Botts; R. W. Hemken; L. S. Bull

1980-01-01

47

77 FR 50613 - Didecyl Dimethyl Ammonium Carbonate and Didecyl Dimethyl Ammonium Bicarbonate; Exemption From the...  

Federal Register 2010, 2011, 2012, 2013

...jointly referred to as DDACB on food contact surfaces when applied...exposure databases. The dietary food exposure assessment was performed...risk assessment for the Group I Cluster is based on an assessment of...Safety 1. Dietary risk from food and feed uses. EPA...

2012-08-22

48

[Bicarbonate-containing dialysate: a critical study].  

PubMed

Renewed interest in bicarbonate as the dialysate base replacement during hemodialysis has introduced new settings on acetate-dialysate delivery systems commercially available. Numerous technical problems are associated with unstable bicarbonate solutions. Therefore, several precautions must be observed: 1) Bicarbonate dialysis requires two concentrates: one containing the base replacement bicarbonate and the other containing basically calcium and magnesium chlorides, 2) A two-stream proportioning system afforded by an appropriate dialysate delivery machine should be used to mix the bicarbonate and acid concentrates, in order to ensure on-line production of the final dialysate, 3) Additional monitors, such as pH monitor, are required to prevent misuse of concentrates. These new ancillary equipments and the relatively high cost of bicarbonate concentrates could slow down the extension of bicarbonate dialysis which is potentially beneficial for all dialysis patients. PMID:6664418

Man, N K; Jehenne, G; Funck-Brentano, J L

1983-01-01

49

Adaptations in urea ammonium excretion in metabolic acidosis in the rat: a reinterpretation.  

PubMed

1. The effects of oral hydrochloric acid, ammonium chloride, sodium bicarbonate and ammonium bicarbonate on urea and ammonium excretion in rats on a constant diet were studied. 2. Hydrochloric acid acidosis significantly reduced urea excretion in the rat, with an equimolar increase in NH+4 excretion and no change in their sum. In ammonium chloride acidosis, most of the additional nitrogen intake is excreted as NH+4 and a small percentage as urea. The converse holds true after administration of ammonium bicarbonate. The physiological significance of this is discussed. 3. The shift in nitrogen excretion from urea to NH+4 in acidosis is interpreted on the basis of bicarbonate production and utilization. Urea formation utilizes HCO-3. For amino acid sources, this utilization is offset by the metabolism of the carbon skeleton, which gives rise to HCO-3. When waste nitrogen is excreted as NH+4, no bicarbonate is utilized and the new HCO-3, generated by the carbon skeleton, hels to maintain hydrogen ion homeostasis. PMID:1056282

Oliver, J; Bourke, E

1975-06-01

50

The electrogenic sodium bicarbonate cotransporter NBCe1 is a high-affinity bicarbonate carrier in cortical astrocytes.  

PubMed

The electrogenic sodium bicarbonate cotransporter NBCe1 (SLC4A4) is a robust regulator of intracellular H(+) and a significant base carrier in many cell types. Using wild-type (WT) and NBCe1-deficient (NBC-KO) mice, we have studied the role of NBCe1 in cortical astrocytes in culture and in situ by monitoring intracellular H(+) using the H(+)-sensitive dye BCECF [2',7'-bis-(carboxyethyl)-5-(and-6)-carboxyfluorescein] in wide-field and confocal microscopy. Adding 0.1-3 mm HCO3(-) to an O2-gassed, HEPES-buffered saline solution lowered the intracellular H(+) concentration with a Km of 0.65 mm HCO3(-) in WT astrocytes, but slowly raised [H(+)]i in NBCe1-KO astrocytes. Human NBCe1 heterologously expressed in Xenopus oocytes could be activated by adding 1-3 mm HCO3(-), and even by residual HCO3(-) in a nominally CO2/HCO3(-)-free saline solution. Our results demonstrate a surprisingly high apparent bicarbonate sensitivity mediated by NBCe1 in cortical astrocytes, suggesting that NBCe1 may operate over a wide bicarbonate concentration in these cells. PMID:24453308

Theparambil, Shefeeq M; Ruminot, Iván; Schneider, Hans-Peter; Shull, Gary E; Deitmer, Joachim W

2014-01-22

51

Effects of sodium bicarbonate ingestion on swim performance in youth athletes  

PubMed Central

The purpose of this study was to evaluate the effect of oral administration of sodium bicarbonate (300 mg·kg-1 b.w.) on swim performance in competitive, (training experience of 6.6 ± 0.6 years) youth, (15.1 ± 0.6 years) male swimmers. The subjects completed a test trial, in a double blind fashion, on separate days, consisting of 4 x 50m front crawl swims with a 1st minute passive rest interval twice, on two occasions: after ingestion of bicarbonate or placebo, 72 hours apart, at the same time of the day. Blood samples were drawn from the finger tip three times during each trial; upon arrival to the laboratory, 60 min after ingestion of placebo or the sodium bicarbonate solution and after the 4 x 50m test, during the 1st min of recovery. Plasma lactate concentration, blood pH, standard bicarbonate and base excess were evaluated. The total time of the 4 x 50 m test trial improved from 1.54.28 to 1.52.85s, while statistically significant changes in swimming speed were recorded only during the first 50m sprint (1.92 vs. 1.97 m·s-1, p < 0.05). Resting blood concentration of HCO-3 increased following the ingestion of sodium bicarbonate from 25.13 to 28.49 mM (p < 0.05). Sodium bicarbonate intake had a statistically significant effect on resting blood pH (7.33 vs. 7.41, p < .05) as well as on post exercise plasma lactate concentration (11.27 vs. 13.06 mM, p < 0.05)). Collectively, these data demonstrate that the ingestion of sodium bicarbonate in youth athletes is an effective buffer during high intensity interval swimming and suggest that such a procedure can be used in youth athletes to increase training intensity as well as swimming performance in competition at distances from 50 to 200 m. Key points Sodium bicarbonate is an effective ergogenic aid, also in youth athletes. Sodium bicarbonate intake improves swimming sprint performance. Sodium bicarbonate intake increases resting blood pH and bicarbonate level

Zajac, Adam; Cholewa, Jaroslaw; Poprzecki, Stanislaw; Waskiewicz, Zbigniew; Langfort, Jozef

2009-01-01

52

Effect of ranitidine on basal and bicarbonate enhanced intragastric PCO2: a tonometric study  

Microsoft Academic Search

A high intragastric PCO2 (iPCO2), determined tonometrically, is the main factor participating in a low gastric intramucosal pH (pHi) and may point to gastric mucosal ischaemia. iPCO2 might also increase, however, after buffering of gastric acid by bicarbonate; the magnitude of this effect and the efficacy of H2 blockers to prevent it are unclear. Ten healthy volunteers (20-24 years) were

J J Kolkman; A B Groeneveld; S G Meuwissen

1994-01-01

53

Electrofocusing in Buffers.  

National Technical Information Service (NTIS)

Methods of electrofocusing in amphoteric or non-amphoteric buffers is disclosed. In such methods, buffers are employed as carrier constituents, and optionally as anolyte and catholyte. Using a buffer electrofocusing system, stability with time has been ac...

A. Chrambach N. Y. Nguyen

1977-01-01

54

Bicarbonate in diabetic ketoacidosis - a systematic review  

Microsoft Academic Search

Objective  This study was designed to examine the efficacy and risk of bicarbonate administration in the emergent treatment of severe\\u000a acidemia in diabetic ketoacidosis (DKA).\\u000a \\u000a \\u000a \\u000a \\u000a Methods  PUBMED database was used to identify potentially relevant articles in the pediatric and adult DKA populations. DKA intervention\\u000a studies on bicarbonate administration versus no bicarbonate in the emergent therapy, acid-base studies, studies on risk association\\u000a with

Horng Ruey Chua; Antoine Schneider; Rinaldo Bellomo

2011-01-01

55

21 CFR 184.1736 - Sodium bicarbonate.  

Code of Federal Regulations, 2013 CFR

...with carbon dioxide. As carbon dioxide is absorbed, a suspension of sodium bicarbonate forms. The slurry is filtered, forming a cake which is washed and dried. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed....

2013-04-01

56

Buffer Modulation of Menadione-Induced Oxidative Stress in Saccharomyces cerevisiae  

PubMed Central

The objective of this study was to compare in vivo the effects of bicarbonate and phosphate buffers on surviving and menadione-induced oxidative stress in yeast cells. The latter were treated with different concentrations of menadione in the presence of these two buffers. If at 25 mM concentration of buffers menadione only slightly reduced yeast surviving, at 50 mM concentration cell killing by menadione was much more pronounced in bicarbonate than in phosphate buffer. Although the content of protein carbonyl groups did not show development of oxidative stress under menadione-induced stress, inactivation of aconitase and decrease in glutathione level mirrored its induction. However, cellular glutathione and aconitase activity decrease did not correlate with yeast survival. In vitro, aconitase was more quickly inactivated in 50 mM carbonate, than in 50 mM phosphate buffer. The possible involvement of the carbonate radical in these processes is discussed.

Lushchak, Oleh V.; Bayliak, Maria M.; Korobova, Olha V.; Levine, Rodney L.; Lushchak, Volodymyr I.

2012-01-01

57

Effect of Two Nitrogen Forms on the Growth and Iron Nutrition of Pea Cultivated in Presence of Bicarbonate  

Microsoft Academic Search

Two cultivars of pea: ‘PS210713’ (‘PS’), sensitive to iron deficiency, and ‘Marveille de Kelvedon’ (‘MK’), tolerant, were cultivated in controlled climatic conditions during one month, on a nutrient solution containing either nitrate (NO3 , 4 mM) or ammonium (NH4 , 4 mM) and in the presence of bicarbonate (10 mM). The effects of these nitrogen forms on the growth and

Zouhaier Barhoumi; Mokdad Rabhi; Mohamed Gharsalli

2007-01-01

58

40 CFR 415.140 - Applicability; description of the sodium bicarbonate production subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the sodium bicarbonate production subcategory. ...MANUFACTURING POINT SOURCE CATEGORY Sodium Bicarbonate Production Subcategory ...Applicability; description of the sodium bicarbonate production...

2009-07-01

59

40 CFR 415.140 - Applicability; description of the sodium bicarbonate production subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the sodium bicarbonate production subcategory. ...MANUFACTURING POINT SOURCE CATEGORY Sodium Bicarbonate Production Subcategory ...Applicability; description of the sodium bicarbonate production...

2010-07-01

60

Bicarbonate and bicarbonate/lactate peritoneal dialysis solutions for the treatment of infusion pain.  

PubMed

A randomized, double-blind, cross-over study was undertaken to determine the effects of novel bicarbonate (38 mM) and bicarbonate (25 mM)/lactate (15 mM) containing peritoneal dialysis (PD) solutions on infusion pain in patients who experienced inflow pain with conventional lactate (40 mM) solution. Pain was assessed using a verbal rating scale and the validated McGill Pain Questionnaire (MPQ). Eighteen patients were recruited to the study. Both novel solutions resulted in highly statistically significant reductions in inflow pain compared to the control lactate solution, as assessed with both the verbal rating scale and the MPQ. For all pain variables assessed, the bicarbonate/lactate solution was more effective than the bicarbonate solution in alleviating pain. In conclusion, both solutions reduced the infusion pain experienced with control solution, but the bicarbonate/lactate solution appears to be the most effective. In contrast to the most widespread current treatment, which is the manual injection of sodium bicarbonate, the bicarbonate/lactate solution does not have the associated increased risk of peritonitis. PMID:9551418

Mactier, R A; Sprosen, T S; Gokal, R; Williams, P F; Lindbergh, M; Naik, R B; Wrege, U; Gröntoft, K C; Larsson, R; Berglund, J; Tranaeus, A P; Faict, D

1998-04-01

61

Bicarbonate and functional CFTR channel are required for proper mucin secretion and link cystic fibrosis with its mucus phenotype  

PubMed Central

Cystic fibrosis (CF) is caused by a nonfunctional chloride and bicarbonate ion channel (CF transmembrane regulator [CFTR]), but the link to the phenomenon of stagnant mucus is not well understood. Mice lacking functional CFTR (Cftr?508) have no lung phenotype but show similar ileal problems to humans. We show that the ileal mucosa in CF have a mucus that adhered to the epithelium, was denser, and was less penetrable than that of wild-type mice. The properties of the ileal mucus of CF mice were normalized by secretion into a high concentration sodium bicarbonate buffer (?100 mM). In addition, bicarbonate added to already formed CF mucus almost completely restored the mucus properties. This knowledge may provide novel therapeutic options for CF.

Gustafsson, Jenny K.; Ermund, Anna; Ambort, Daniel; Johansson, Malin E.V.; Nilsson, Harriet E.; Thorell, Kaisa; Hebert, Hans; Sjovall, Henrik

2012-01-01

62

DWPF ammonium ion analysis  

SciTech Connect

Ammonium nitrate production during the operation of the Defense Waste Processing Facility (DWPF) has been identified as a major problem. The accumulation of ammonium nitrate deposits in the vent system of the chemical processing cell has substantial safety implications and will require analysis of ammonium ions within DWPF process samples. As a part of the research and development of the DWPF at TNX, an ammonium analysis method developed by Dionex Corporation has been identified and confirmed to provide the required information. This memorandum describes the technical basis of the method, the accuracy and precision of the method, known interferences, and maintenance details.

Eibling, R.E.

1992-06-05

63

Influence of steady-state alterations in acid-base equilibrium on the fate of administered bicarbonate in the dog.  

PubMed Central

Previous workers have shown that metabolic acidosis increases the apparent space through which administered bicarbonate is distributed. This finding has been ascribed to the accompanying acidemia and to the consequent availability of a large quantity of hydrogen ion that accumulates on nonbicarbonate tissue buffers during the development of acidosis. To test this hypothesis, bicarbonate space was measured in dogs with a broad range of steady-state plasma [HCO-3] in association with alkalemia as well as with acidemia. Appropriate combinations of pH and plasma [HCO-3] were achieved by pretreating the animals to produce graded degrees of each of the four cardinal, chronic acid-base disorders. Metabolic acidosis (n = 15) was produced by prolonged HCl-feeding; metabolic alkalosis (n = 17) by diuretics and a chloride-free diet; and respiratory acidosis (n = 9) and alkalosis (n = 8) by means of an environmental chamber. Animals with normal acid-base status (n = 4) were also studied. Sodium bicarbonate (5 mmol/kg) was infused over 10 min to the unanesthetized animals; observations were carried out over 90 min. The results obtained from animals with metabolic acid-base disturbances demonstrated an inverse relationship between bicarbonate space and initial plasma pH, confirming the previous findings of others. By contrast, the results obtained in animals with respiratory acid-base disturbances demonstrated a direct relationship between bicarbonate space and initial plasma pH. The pooled data revealed that bicarbonate space is, in fact, quite independent of the initial pH but is highly correlated with the initial level of extracellular [HCO-3]; dogs with low extracellular [HCO-3] (congruent to 10 meq/liter) whether acidemic or alkalemic, have a bicarbonate space that is 25% larger than normal and some 50% larger than in dogs with high extracellular [HCO-3] (congruent to 50 meq/liter). We conclude from these results that the increased bicarbonate space in metabolic acidosis (and respiratory alkalosis) does not reflect the availability of more hydrogen ions for release during bicarbonate administration, but merely evidences the wider range of titration (delta pH) of nonbicarbonate buffers that occurs during alkali loading whenever plasma [HCO-3] is low.

Adrogue, H J; Brensilver, J; Cohen, J J; Madias, N E

1983-01-01

64

Sodium Bicarbonate in Chemical Flooding: Part 1: Topical Report.  

National Technical Information Service (NTIS)

To compare oil recovery and alkali consumption in alkaline flooding using sodium bicarbonate with other alkaline agents, coreflooding experiments were performed in turn with viscosified sodium bicarbonate and viscosified sodium carbonate solutions. Oil re...

D. A. Peru P. B. Lorenz

1987-01-01

65

Reappraisal of bicarbonate secretion by the human oesophagus.  

PubMed Central

BACKGROUND AND AIMS: Administration of omeprazole to healthy volunteers was recently reported to increase proximal duodenal mucosal bicarbonate secretion. As human oesophagus also secretes bicarbonate, the hypothesis was tested that omeprazole may stimulate oesophageal bicarbonate secretion and thus contribute to the therapeutic efficacy of the drug in gastro-oesophageal reflux disease. SUBJECTS AND METHODS: In nine healthy volunteers, oesophageal "steady state" perfusion of a 10 cm open segment of distal oesophagus was performed twice in random order. The volunteers were pretreated with either 60 mg/day omeprazole for three days and 80 mg intravenous omeprazole before perfusion or 600 mg/day ranitidine for three days and 50 mg/h intravenously during the perfusion. Saliva and samples of aspirate from the perfused oesophagus and stomach were collected and bicarbonate concentrations were measured. RESULTS: The median rates (95% confidence intervals) of intrinsic oesophageal bicarbonate secretion, corrected for contaminating salivary and gastric bicarbonate, were 89 (33-150) and 121 (63-203) mumol/h/10 cm (p > 0.5) in omeprazole and ranitidine treated subjects respectively. Salivary and gastric bicarbonate contaminating the oesophagus accounted for 14% and 3%, respectively, of total oesophageal bicarbonate output. CONCLUSIONS: Bicarbonate secretory capacity of the human oesophagus is less than previously assumed, and the clinical relevance of intrinsic oesophageal bicarbonate for mucosal defence may be overestimated. As omeprazole and ranitidine did not affect bicarbonate secretion differently there was no evidence that omeprazole acts on bicarbonate secretory cells in the oesophageal mucosa.

Mertz-Nielsen, A; Hillings?, J; Bukhave, K; Rask-Madsen, J

1997-01-01

66

The Bicarbonate Transporter Is Essential for Bacillus anthracis Lethality  

PubMed Central

In the pathogenic bacterium Bacillus anthracis, virulence requires induced expression of the anthrax toxin and capsule genes. Elevated CO2/bicarbonate levels, an indicator of the host environment, provide a signal ex vivo to increase expression of virulence factors, but the mechanism underlying induction and its relevance in vivo are unknown. We identified a previously uncharacterized ABC transporter (BAS2714-12) similar to bicarbonate transporters in photosynthetic cyanobacteria, which is essential to the bicarbonate induction of virulence gene expression. Deletion of the genes for the transporter abolished induction of toxin gene expression and strongly decreased the rate of bicarbonate uptake ex vivo, demonstrating that the BAS2714-12 locus encodes a bicarbonate ABC transporter. The bicarbonate transporter deletion strain was avirulent in the A/J mouse model of infection. Carbonic anhydrase inhibitors, which prevent the interconversion of CO2 and bicarbonate, significantly affected toxin expression only in the absence of bicarbonate or the bicarbonate transporter, suggesting that carbonic anhydrase activity is not essential to virulence factor induction and that bicarbonate, and not CO2, is the signal essential for virulence induction. The identification of this novel bicarbonate transporter essential to virulence of B. anthracis may be of relevance to other pathogens, such as Streptococcus pyogenes, Escherichia coli, Borrelia burgdorferi, and Vibrio cholera that regulate virulence factor expression in response to CO2/bicarbonate, and suggests it may be a target for antibacterial intervention.

Wilson, Adam C.; Soyer, Magali; Hoch, James A.; Perego, Marta

2008-01-01

67

The rhesus protein RhCG: a new perspective in ammonium transport and distal urinary acidification  

Microsoft Academic Search

Urinary acidification is a complex process requiring the coordinated action of enzymes and transport proteins and resulting in the removal of acid and the regeneration of bicarbonate. Proton secretion is mediated by luminal H+-ATPases and requires the parallel movement of NH3, and its protonation to NH4+, to provide sufficient buffering. It has been long assumed that ammonia secretion is a

Carsten A Wagner; Olivier Devuyst; Hendrica Belge; Soline Bourgeois; Pascal Houillier

2011-01-01

68

Renal bicarbonate reabsorption in the new-born dog  

PubMed Central

1. Renal bicarbonate reabsorption was measured in thirty new-born dogs 2-27 days of age. Plasma bicarbonate was varied in the puppies by exchanging their blood with blood containing high levels of bicarbonate and low levels of chloride. 2. The exchange transfusion resulted in increases of plasma pH, PCO2 and bicarbonate in the puppies without changing plasma sodium and potassium or glomerular filtration rate (g.f.r.) and body weight. 3. There was no tubular reabsorption maximum (Tm) for bicarbonate and reabsorption values as high as 50 ?equiv/ml. g.f.r. could be attained. No animals excreted bicarbonate at plasma levels below 25 mM and some animals had plasma bicarbonate threshold values in excess of 40 mM. 4. Bicarbonate reabsorption increased as arterial PCO2 rose (r = 0·62) but this was due to the rise of filtered bicarbonate since (a) there was no correlation between arterial PCO2 and bicarbonate reabsorption when factored by filtered bicarbonate and (b) lowering arterial PCO2 by mechanical hyperventilation did not reduce bicarbonate reabsorption corrected for filtered load. 5. Inhibition of renal carbonic anhydrase by acetazolamide (50 mg/kg) resulted in an inhibition of bicarbonate reabsorption of only 4·5 ?equiv/ml. g.f.r. (less than 20% of the total). Even with renal carbonic anhydrase inhibited, there was no bicarbonate Tm and bicarbonate reabsorption values as high as 40 ?equiv/ml. g.f.r. could be attained. 6. There was good correlation (r = 0·82) between inhibition of sodium and bicarbonate reabsorption during renal carbonic anhydrase inhibition. However, with carbonic anhydrase inhibited, there was no correlation between arterial PCO2 and bicarbonate reabsorption. 7. These results demonstrate that tubular bicarbonate reabsorption mechanisms in the new-born dog are as efficient as those reported for the adult as long as body fluid and plasma sodium and potassium levels are carefully maintained. 8. The results are also consistent with a bicarbonate reabsorptive mechanism explained either by direct ionic bicarbonate reabsorption or by hydrogen ion secretion with diffusion of carbonic acid.

Kleinman, Leonard I.

1978-01-01

69

Comparison of in vitro AGE formation between standard PD fluid and a novel bicarbonate/lactate formulation.  

PubMed

Peritoneal advanced glycation end-product (AGE) formation may be accelerated by glucose degradation products produced as a consequence of heat sterilization of peritoneal dialysis (PD) fluid. The formation of these degradation products is reduced if the glucose is separated from the buffers during heat sterilization. This pilot study compared in vitro AGE formation in PD fluid (1.36% and 3.86% glucose) heat sterilized in a two-compartment bag (bicarbonate/lactate buffer) with that in a standard, single-compartment bag (lactate buffer, Dianeal). Peritoneal dialysis fluids were incubated with human serum albumin (HSA, 1 g/L), as a model protein, at 37 degrees C for 0, 5, and 20 days. Formation of AGEs was assessed by measuring fluorescence at each time point. Advanced glycation end-product formation was greater in lactate PD fluid compared with bicarbonate/lactate PD fluid of equivalent glucose strength. Advanced glycation end-product formation in the lactate PD fluid containing 1.36% glucose was comparable to that in the bicarbonate/lactate PD fluid containing 3.86% glucose. The rate of increase in fluorescence per day was greater in the first 5 days of incubation than in the subsequent 15 days. These results are compatible with the presence of greater amounts of glucose-degradation products in the standard single-compartment bag resulting in enhanced AGE formation. PMID:10649722

Millar, D J; Holmes, C; Faict, D; Dawnay, A

1998-01-01

70

CHLORIDEDETERMINATION IN HIGH IONIC STRENGTH SOLUTION OF AMMONIUM ACETATE USING NEGATIVE ION ELECTRON SPRAY IONIZATION (HPLC/MS)  

EPA Science Inventory

A precise ion chromatography method has been developed for the determination of chloride in high ionic strength ammonium acetate solutions (10-5 M-5 M) using sodium carbonate/sodium bicarbonate as eluent. Negative ion electrospray ionization (ESI) mass spectrometry was used for q...

71

Bicarbon valve - European multicenter clinical evaluation  

Microsoft Academic Search

Objective: Fifteen collaborating centers in eight countries present their pooled experience with the new Bicarbon™ bileaflet valve. Methods: Between 4\\/90 and 4\\/96, 1351 patients, 806 males and 545 females, aged 10 to 83, mean 58.4±12.4, underwent valve implantation. Operations: AVR, 726; MVR, 475; DVR, 150. Additional procedures: CABG, 211; TV repair, 64; other, 152. Results: Mortality: 67 early (seven valve

J. B Borman; W. G. B Brands; L Camilleri; M Cotrufo; W Daenen; I Gandjbakhch; C Infantes; A Khayat; F Laborde; A Pellegrini; A Piwnica; B Reichart; R Sharony; R Walesby; H Warembourg

1998-01-01

72

Bicarbon valve - European multicenter clinical evaluation  

Microsoft Academic Search

Objective: Fifteen collaborating centers in eight countries present their pooled experience with the new Bicarbon y bileaflet valve. Methods: Between 4\\/90 and 4\\/96, 1351 patients, 806 males and 545 females, aged 10 to 83, mean 58.4 ? 12.4, underwent valve implantation. Operations: aortic valve replacement (AVR), 726; mitral valve replacement (MVR), 475; double valve replacement (DVR), 150. Additional procedures: CABG,

J. B. Bormana; W. G. B. Brandsc; L. Camilleri; M. Cotrufoe; I. Gandjbakhch; C. Infantes; A. Khayati; F. Laborde; A. Pellegrini; A. Piwnica; B. Reichart; R. Sharony; R. Walesby; H. Warembourg; Clermond Ferrand; Grosshadern Klinikum

2010-01-01

73

Ammonium nitrate explosive systems  

DOEpatents

Novel explosives which comprise mixtures of ammonium nitrate and an ammonium salt of a nitroazole in desired ratios are disclosed. A preferred nitroazole is 3,5-dinitro-1,2,4-triazole. The explosive and physical properties of these explosives may readily be varied by the addition of other explosives and oxidizers. Certain of these mixtures have been found to act as ideal explosives.

Stinecipher, Mary M. (Los Alamos, NM); Coburn, Michael D. (Los Alamos, NM)

1981-01-01

74

Sodium Is Not Required for Chloride Efflux via Chloride/Bicarbonate Exchanger from Rat Thymic Lymphocytes  

PubMed Central

Sodium-dependent Cl?/HCO3? exchanger acts as a chloride (Cl?) efflux in lymphocytes. Its functional characterization had been described when Cl? efflux was measured upon substituting extracellular sodium (Na+) by N-methyl-D-glucamine (NMDG). For Na+ and Cl? substitution, we have used D-mannitol or NMDG. Thymocytes of male Wistar rats aged 7–9 weeks were used and intracellular Cl? was measured by spectrofluorimetry using MQAE dye in bicarbonate buffers. Chloride efflux was measured in a Cl?-free buffer (Cl? substituted with isethionate acid) and in Na+ and Cl?-free buffer with D-mannitol or with NMDG. The data have shown that Cl? efflux is mediated in the absence of Na+ in a solution containing D-mannitol and is inhibited by H2DIDS. Mathematical modelling has shown that Cl? efflux mathematical model parameters (relative membrane permeability, relative rate of exchanger transition, and exchanger efficacy) were the same in control and in the medium in which Na+ had been substituted by D-mannitol. The net Cl? efflux was completely blocked in the NMDG buffer. The same blockage of Cl? efflux was caused by H2DIDS. The study results allow concluding that Na+ is not required for Cl? efflux via Cl?/HCO3? exchanger. NMDG in buffers cannot be used for substituting Na+ because NMDG inhibits the exchanger.

Stakisaitis, Donatas; Meilus, Vaidevutis; Juska, Alfonsas; Matusevicius, Paulius; Didziapetriene, Janina

2014-01-01

75

Sodium acetate as a replacement for sodium bicarbonate in medical toxicology: a review.  

PubMed

Sodium bicarbonate is central to the treatment of many poisonings. When it was placed on the FDA drug shortage list in 2012, alternative treatment strategies to specific poisonings were considered. Many hospital pharmacies, poison centers, and medical toxicologists proposed sodium acetate as an adequate alternative, despite a paucity of data to support its use in medical toxicology. The intention of this review is to educate the clinician on the use of sodium acetate and to advise them on the potential adverse events when given in excess. We conducted a literature search focused on the pharmacology of sodium acetate, its use as a buffer in pathologic acidemia and dialysis baths, and potential adverse events associated with excess sodium acetate infusion. It appears safe to replace sodium bicarbonate infusion with sodium acetate on an equimolar basis. The metabolism of acetate, however, is more complex than bicarbonate. Future prospective studies will be needed to confirm the efficacy of sodium acetate in the treatment of the poisoned patient. PMID:23636658

Neavyn, Mark J; Boyer, Edward W; Bird, Steven B; Babu, Kavita M

2013-09-01

76

The anaerobic oxidation of ammonium  

Microsoft Academic Search

From recent research it has become clear that at least two different possibilities for anaerobic ammonium oxidation exist in nature. `Aerobic' ammonium oxidizers like Nitrosomonas eutropha were observed to reduce nitrite or nitrogen dioxide with hydroxylamine or ammonium as electron donor under anoxic conditions. The maximum rate for anaerobic ammonium oxidation was about 2 nmol NH+4 min?1 (mg protein)?1 using

Mike S. M Jetten; Marc Strous; Katinka T van de Pas-Schoonen; Jos Schalk; Udo G. J. M van Dongen; Astrid A van de Graaf; Susanne Logemann; Gerard Muyzer; Mark C. M van Loosdrecht; J. Gijs Kuenen

1998-01-01

77

Bicarbonate Contributes to GABAA Receptor-Mediated Neuronal Excitation in Surgically-Resected Human Hypothalamic Hamartomas  

PubMed Central

SUMMARY The role of bicarbonate (HCO3-) in GABAA receptor-mediated depolarization of human hypothalamic hamartoma (HH) neurons was investigated using cellular electrophysiological and calcium imaging techniques. Activation of GABAA receptors with muscimol (30 ?M) provoked neuronal excitation in over 70% of large (18-22 ?M) HH neurons in HCO3- buffer. Subsequent perfusion of HCO3--free HEPES buffer produced partial suppression of muscimol-induced excitation. Additionally, 53% of large HH neurons under HCO3--free conditions exhibited reduced intracellular calcium accumulation by muscimol. These results suggest that HCO3- efflux through GABAA receptors on a subpopulation of large HH neurons may contribute to membrane depolarization and subsequent activation of L-type calcium channels.

Do-Young, Kim; Fenoglio, Kristina A.; Kerrigan, John F.; Rho, Jong M.

2009-01-01

78

Molecular Structure of Ammonium ion  

NSDL National Science Digital Library

The first widespread production of ammonium compounds occurred during the 1890s when ammonium sulfate was produced as a by-product from coke oven gas. Ammonium ion is produced as a product of the reaction of water and ammonia. Often, ammonium salts are isomorphous. They have a similar solubility to potassium and rubidium salts, whose ions are similar in size to ammonium. The ion is most stable in the presence of a large compound with a single negative charge.

2002-09-10

79

Tri-State Buffer  

NSDL National Science Digital Library

This interactive presentation, created by Terry Bartelt and hosted by the Electromechanical Digital Library, discusses the tri-state buffer used in devices employing digital circuitry. A tri-state buffer is "one type of device that is used in digital circuits receiving two logic states but producing three different types of output signals." The presentation is filled with useful flash animations presenting the buffer's use. Furthermore, a series of slides presents the application of this device in different situations. Once complete, a short four-question quiz is provided to test the full understanding of the different concepts.

Bartelt, Terry L.

2009-04-20

80

Analysis of bicarbonate binding to crocodilian hemoglobin.  

PubMed

Crocodilian hemoglobin has a high intrinsic oxygen affinity but does not react with those organic phosphate esters that normally control the oxygen affinity of blood in higher vertebrates. Instead, its oxygen affinity is greatly lowered by CO2. The present study was undertaken to determine the nature of the CO2 binding to the hemoglobin of a crocodilian species, the Caiman, both qualitatively and quantitatively. The following parameters were measured: (a) carbamino compounds of deoxy- and oxyhemoglobin, (b) the effect of CO2 (at constant pH) on the oxygen affinity of Caiman hemoglobin, (c) total CO2 concentration of hemoglobin solutions at different pH and pCO2 values, and (d) the effect of CO2 on CD spectra of Caiman aquomethemoglobin. An analysis of the results of these measurements revealed that CO2 binding in the form of carbamate was not oxygen-linked and cannot, therefore, mediate the CO2 effect on the oxygen affinity. It was found, however, that 2 mol of bicarbonate can be bound/hemoglobin tetramer and that the association constant of the bicarbonate anion greatly depends upon the state of ligation. At pH 7.02 and 25 degrees C, a numerical value of 2.0 X 10(3) M-1 was obtained for deoxyhemoglobin, while for oxyhemoglobin no significant bicarbonate binding could be observed. At more alkaline pH (pH greater than or equal to 7.5), the association constant for deoxyhemoglobin decreases. Circular dichroism of Caiman aquomethemoglobin decreased considerably in the 287-nm region upon addition of CO2 at constant pH, an effect very similar to the one caused by inositol hexaphosphate in human aquomethemoglobin. PMID:7263661

Bauer, C; Forster, M; Gros, G; Mosca, A; Perrella, M; Rollema, H S; Vogel, D

1981-08-25

81

Mechanisms of contrast-induced nephropathy reduction for saline (NaCl) and sodium bicarbonate (NaHCO3).  

PubMed

Nephropathy following contrast media (CM) exposure is reduced by administration before, during, and after the contrast procedure of either isotonic sodium chloride solution (Saline) or isotonic sodium bicarbonate solution (IsoBicarb). The reasons for this reduction are not well established for either sodium salt; probable mechanisms are discussed in this paper. For Saline, the mechanism for the decrease in CIN is likely related primarily to the increased tubular flow rates produced by volume expansion and therefore a decreased concentration of the filtered CM during transit through the kidney tubules. Furthermore, increased tubular flow rates produce a slight increase in tubular pH resulting from a fixed acid excretion in an increased tubular volume. The mechanism for the decreased CIN associated with sodium bicarbonate includes the same mechanisms listed for Saline in addition to a renal pH effect. Increased filtered bicarbonate anion raises both tubular pH and tubular bicarbonate anion levels toward blood physiologic levels, thus providing increased buffer for reactive oxygen species (ROS) formed in the tubules as a result of exposure to CM in renal tubular fluid. PMID:24826379

Burgess, W Patrick; Walker, Phillip J

2014-01-01

82

Mechanisms of Contrast-Induced Nephropathy Reduction for Saline (NaCl) and Sodium Bicarbonate (NaHCO3)  

PubMed Central

Nephropathy following contrast media (CM) exposure is reduced by administration before, during, and after the contrast procedure of either isotonic sodium chloride solution (Saline) or isotonic sodium bicarbonate solution (IsoBicarb). The reasons for this reduction are not well established for either sodium salt; probable mechanisms are discussed in this paper. For Saline, the mechanism for the decrease in CIN is likely related primarily to the increased tubular flow rates produced by volume expansion and therefore a decreased concentration of the filtered CM during transit through the kidney tubules. Furthermore, increased tubular flow rates produce a slight increase in tubular pH resulting from a fixed acid excretion in an increased tubular volume. The mechanism for the decreased CIN associated with sodium bicarbonate includes the same mechanisms listed for Saline in addition to a renal pH effect. Increased filtered bicarbonate anion raises both tubular pH and tubular bicarbonate anion levels toward blood physiologic levels, thus providing increased buffer for reactive oxygen species (ROS) formed in the tubules as a result of exposure to CM in renal tubular fluid.

Burgess, W. Patrick; Walker, Phillip J.

2014-01-01

83

Honeycomb-like graphitic ordered macroporous carbon prepared by pyrolysis of ammonium bicarbonate  

SciTech Connect

Graphical abstract: Honeycomb-like graphitic macroporous carbon (HGMC) with big pores centered at 1-3 {mu}m, has been prepared by controlling the reaction temperature and amount of NH{sub 4}HCO{sub 3} at 550 {sup o}C in a sealed reaction system. Possible formation processes of HGMC are discussed on the experimental results. It is believed that the in situ formed MgO microparticles play a template role during the preparation of HGMC. Highlights: {yields} Honeycomb-like graphitic carbon was synthesized at 550 {sup o}C. {yields} The honeycomb-like graphitic carbon is macroposous structures. {yields} The formed MgO microparticles play a template role during the HGMC formation. {yields} The method can be expended to synthesize other porous or hollow carbon material. -- Abstract: Honeycomb-like graphitic macroporous carbon (HGMC) was synthesized by means of pyrolysis of NH{sub 4}HCO{sub 3} using Mg powder as reductant in an autoclave at 550 {sup o}C. The characterization of structure and morphology was carried out by X-ray diffraction (XRD), Raman spectrum, field-emission scanning electron microscopy (FESEM), and (High-resolution) transmission electron microscope [(HR)TEM]. The results of nitrogen adsorption-desorption indicate that the products are macropore materials with the pore size of 1-3 {mu}m, and the Brunauer-Emett-Teller (BET) surface area was 14 m{sup 2}/g. As a typical morphology, the possible growth process of HGMC was also investigated and discussed. The experimental results show that the in situ formed MgO microparticles play a template role during the HGMC formation.

Wang, Liancheng [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, Shandong 250100 (China)] [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, Shandong 250100 (China); Zhang, Junhao, E-mail: jhzhang6@mail.ustc.edu.cn [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, Shandong 250100 (China) [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, Shandong 250100 (China); School of Biology and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Xu, Liqiang; Qian, Yitai [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, Shandong 250100 (China)] [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, Shandong 250100 (China)

2011-10-15

84

Bench-to-bedside review: Treating acid-base abnormalities in the intensive care unit - the role of buffers  

PubMed Central

The recognition and management of acid–base disorders is a commonplace activity for intensivists. Despite the frequency with which non-bicarbonate-losing forms of metabolic acidosis such as lactic acidosis occurs in critically ill patients, treatment is controversial. This article describes the properties of several buffering agents and reviews the evidence for their clinical efficacy. The evidence supporting and refuting attempts to correct arterial pH through the administration of currently available buffers is presented.

Gehlbach, Brian K; Schmidt, Gregory A

2004-01-01

85

Studies on Ammonium Perchlorate Combustion.  

National Technical Information Service (NTIS)

This publication contains four articles: The effect of aluminum on the combustion of ammonium perchlorate with polyformaldehyde; Kinetics of the high-temperature thermal decomposition of ammonium perchlorate; Causes for anomalies during combustion of ammo...

A. A. Zenin G. B. Manelis A. P. Glazkova L. D. Romodanova

1969-01-01

86

40 CFR 180.1177 - Potassium bicarbonate; exemption from the requirement of a tolerance.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Potassium bicarbonate; exemption from the requirement...Exemptions From Tolerances § 180.1177 Potassium bicarbonate; exemption from the requirement...tolerance. The biochemical pesticide potassium bicarbonate is exempted from...

2013-07-01

87

40 CFR 180.1176 - Sodium bicarbonate; exemption from the requirement of a tolerance.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Sodium bicarbonate; exemption from the requirement...Tolerances § 180.1176 Sodium bicarbonate; exemption from the requirement... The biochemical pesticide sodium bicarbonate is exempted from the...

2010-07-01

88

40 CFR 180.1176 - Sodium bicarbonate; exemption from the requirement of a tolerance.  

Code of Federal Regulations, 2010 CFR

... 2009-07-01 false Sodium bicarbonate; exemption from the requirement...Tolerances § 180.1176 Sodium bicarbonate; exemption from the requirement... The biochemical pesticide sodium bicarbonate is exempted from the...

2009-07-01

89

Cytosolic Ca2+ Buffers  

PubMed Central

“Ca2+ buffers,” a class of cytosolic Ca2+-binding proteins, act as modulators of short-lived intracellular Ca2+ signals; they affect both the temporal and spatial aspects of these transient increases in [Ca2+]i. Examples of Ca2+ buffers include parvalbumins (? and ? isoforms), calbindin-D9k, calbindin-D28k, and calretinin. Besides their proven Ca2+ buffer function, some might additionally have Ca2+ sensor functions. Ca2+ buffers have to be viewed as one of the components implicated in the precise regulation of Ca2+ signaling and Ca2+ homeostasis. Each cell is equipped with proteins, including Ca2+ channels, transporters, and pumps that, together with the Ca2+ buffers, shape the intracellular Ca2+ signals. All of these molecules are not only functionally coupled, but their expression is likely to be regulated in a Ca2+-dependent manner to maintain normal Ca2+ signaling, even in the absence or malfunctioning of one of the components.

Schwaller, Beat

2010-01-01

90

Metabolic effects of bicarbonate in the treatment of diabetic ketoacidosis  

Microsoft Academic Search

The effect of intravenous bicarbonate on the changes in intermediary metabolites during the initial treatment of diabetic ketoacidosis was examined in 16 patients. The results were compared with the changes seen in 16 patients receiving intravenous saline. Infusion of 150 mmol (mEq) bicarbonate significantly delayed the fall in blood lactate, lactate:pyruvate ratio, and total ketone bodies observed in the saline

P J Hale; J Crase; M Nattrass

1984-01-01

91

Bicarbonate reabsorption in the dog with experimental renal disease  

Microsoft Academic Search

Bicarbonate reabsorption in the dog with experimental renal disease. Renal bicarbonate reabsorption (expressed per unit of glomerular filtration rate, GFR) has been reported to be diminished in uremic man and uremic rats. Both the increases in parathyroid hormone concentrations and in natriuretic forces have been considered to play a role in this change. The increased kaliuresis per nephron observed in

R William Schmidt; Neal S Bricker; George Gavellas

1976-01-01

92

Effect of Sodium Bicarbonate Preloading on Ischemic Renal Failure.  

National Technical Information Service (NTIS)

Rats pretreated with sodium bicarbonate were functionally protected from the damage of bilateral renal artery occlusion. The rise in serum creatinine (day 1 minus day 0) during the first 24 h after ischemia was lower in the bicarbonate-loaded animals vers...

J. L. Atkins

1986-01-01

93

Improved acidosis correction and recovery of mesothelial cell mass with neutral-pH bicarbonate dialysis solution among children undergoing automated peritoneal dialysis.  

PubMed

Acid-base balance and peritoneal membrane longevity are of utmost relevance for pediatric patients undergoing peritoneal dialysis (PD). PD fluids with neutral pH and reduced glucose degradation product contents are considered more biocompatible, because they preserve peritoneal cell functions in vitro. To investigate the clinical effects of a novel PD fluid buffered with 34 mM pure bicarbonate at neutral pH, a randomized, prospective, crossover comparison with conventional, acidic, 35 mM lactate PD fluid was performed for two consecutive 12-wk periods with 28 children (age, 6 mo to 15 yr) undergoing automated PD (APD). Blood bicarbonate levels and arterial pH were significantly higher after 3 mo of bicarbonate PD (24.6 +/- 2.3 mM and 7.43 +/- 0.06, respectively), compared with lactate PD (22.8 +/- 3.9 mM and 7.38 +/- 0.05, respectively; P < 0.05). This effect was reversible among patients who returned from bicarbonate to lactate fluid. Low initial pH and young patient age independently predicted increased blood pH during bicarbonate APD. Peritoneal equilibration tests revealed subtle changes in solute transport, with a less steep creatinine equilibration curve during bicarbonate dialysis, suggesting reduced peritoneal vasodilation. The peritoneal release of carcinogen antigen-125 increased twofold during bicarbonate APD (29 +/- 15 versus 15 +/- 8 U/ml per 4 h, P < 0.01), which is consistent with recovery of the mesothelial cell layer. This effect was fully reversed when the patients returned to lactate fluid. Effluent carcinogen antigen-125 levels were inversely correlated with peritoneal glucose exposure during lactate but not bicarbonate APD, indicating improved in vivo mesothelial cell tolerance of high-dose glucose with the neutral-pH PD fluid with reduced glucose degradation product content. Among children undergoing APD, neutral-pH, bicarbonate-buffered PD fluid provides more effective correction of metabolic acidosis and better preservation of peritoneal cell mass than do conventional, acidic, lactate-based fluids. PMID:14514742

Haas, Susanne; Schmitt, Claus Peter; Arbeiter, Klaus; Bonzel, Klaus-Eugen; Fischbach, Michel; John, Ulrike; Pieper, Anne-Kathrin; Schaub, Thomas Patrick; Passlick-Deetjen, Jutta; Mehls, Otto; Schaefer, Franz

2003-10-01

94

Potassium bicarbonate, but not sodium bicarbonate, reduces urinary calcium excretion and improves calcium balance in healthy men  

Microsoft Academic Search

Potassium bicarbonate, but not sodium bicarbonate, reduces urinary calcium excretion and improves calcium balance in healthy men. Previous studies demonstrated that the administration of NaHCO3 or sodium citrate had either only a small effect to reduce urinary Ca excretion or no effect, but that potassium citrate significantly reduced urinary Ca excretion. In order to further evaluate and compare the effects

Jacob Lemann; Richard W Gray; Joan A Pleuss

1989-01-01

95

Ammonium Homeostasis and Human Rhesus Glycoproteins  

Microsoft Academic Search

The brain ammonium production is detoxified by astrocytes, the gut ammonium production is detoxified by hepatic cells, and the renal ammonium production plays a major role in renal acid excretion. As a result of ammonium handling in these organs, the ammonium and pH values are strictly regulated in plasma. Up until recently, it was accepted that mammalian cell transmembrane ammonium

Gabrielle Planelles

2007-01-01

96

Stimulation of Guanylyl Cyclase-D by Bicarbonate  

PubMed Central

Guanylyl cyclases (GCs) catalyze the conversion of GTP to the second messenger cGMP. While some transmembrane GCs are receptors for extracellular ligands, other transmembrane GCs such as retinal-specific GC-E and GC-F are stimulated by cellular proteins. GC-D is expressed in a special group of olfactory sensory neurons. However, the direct regulatory mechanism of GC-D activity is not completely understood. Here we have demonstrated that bicarbonate directly increases the activity of purified GC-D. Bicarbonate also increases the cGMP levels in cells expressing GC-D. These results identify bicarbonate as a small molecule that regulates GC-D.

Guo, Dagang; Zhang, J. Jillian; Huang, Xin-Yun

2009-01-01

97

Buffered Telemetry Demodulator  

NASA Technical Reports Server (NTRS)

Buffered telemetry demodulator (BTD) is radio receiver designed mainly for recovery of low-rate data binery phase-modulated onto square-wave subcarrier on sinusoidal or suppressed sinusoidal carrier signal and received at low symbol-to-noise ratio. In BTD, received signal not only processed in real time but also recorded and subsequently reprocessed to recover data otherwise lost. BTD could be implemented on general-purpose computer workstation.

Tsou, Haiping; Hinedi, Sami M.; Shah, Biren; Lee, Robert

1995-01-01

98

Simultaneous routing and buffer insertion with restrictions on buffer locations  

Microsoft Academic Search

During the routing of global interconnects, macro blocks formuseful routing regions which allow wires to go through but forbidbuffers to be inserted. They give restrictions on bufferlocations. In this paper, we take these buffer location restrictionsinto consideration and solve the simultaneous mazerouting and buffer insertion problem. Given a block placementdefining buffer location restrictions and a pair of pins(a source and

Hai Zhou; D. F. Wong; I-Min Liu; Adnan Aziz

1999-01-01

99

Hydrothermal synthesis of ammonium illite  

USGS Publications Warehouse

Synthetic gel and glass of illitic composition, natural kaolinite, and mixed-layer illite-smectite were used as starting materials for hydrothermal synthesis of ammonium illite. Ammonium illite was prepared from synthetic gel by hydrothermal treatment at 300??C. The onset of crystallization began within 3 h, and well-crystallized ammonium illite appeared at 24 h. Increasing reaction time (up to four weeks) led to many illite layers per crystal. In the presence of equivalent proportions of potassium and ammonium, the gel was transformed to illite with equimolar contents of K and NH4. In contrast, synthesis using glass under the same conditions resulted in a mixture of mixed-layer ammonium illite-smectite with large expandability and discrete illite. Hydrothermal treatments of the fine fractions of natural kaolinite and illite-smectite produced ammonium illite from kaolinite but the illite-smectite remained unchanged.

Sucha, V.; Elsass, F.; Eberl, D. D.; Kuchta, L'.; Madejova, J.; Gates, W. P.; Komadel, P.

1998-01-01

100

Distal Renal Tubular Acidosis in Infancy: A Bicarbonate Wasting State  

ERIC Educational Resources Information Center

Studied were three unrelated infants with distal renal tubular acidosis (a condition characterized by an inability to acidify the urine to minimal pH levels resulting in the loss of bicarbonates). (DB)

Rodriguez-Soriano, J.; And Others

1975-01-01

101

Bicarbonate is a recycling substrate for cyanase  

SciTech Connect

Cyanase catalyzes HCO/sub 3//sup -/-dependent decomposition of cyanate to NH/sub 4//sup +/ and HCO/sub 3//sup -/. Previous studies provided evidence that carbamate is an initial product and that the kinetic mechanism is rapid equilibrium random (HCO/sub 3//sup -/ serving as substrate as opposed to activator). Direct evidence for this mechanism was obtained in this study by (1) identifying the products formed from (/sup 14/C)HCO/sub 3//sup -/ or (/sup 14/C)OCN/sup -/, (2) identifying the products formed from (/sup 13/C)HCO/sub 3//sup -/ in the presence of (/sup 18/O)H/sub 2/O, and (3) determining whether CO/sub 2/ or HCO/sub 3//sup -/ serve as substrate and are formed as product. Carbon dioxide (not HCO/sub 3//sup -/) is produced in stoichiometric amounts from both HCO/sub 3//sup -/ and OCN/sup -/. Bicarbonate (not CO/sub 2/) is the substrate. Oxygen-18 from (/sup 18/O)H/sub 2/O is not incorporated into CO/sub 2/ formed from either HCO/sub 3//sup -/ or OCN/sup -/. These results indicate that decomposition of cyanate is not a hydrolysis reaction and that HCO/sub 3//sup -/ functions as a substrate.

Johnson, W.V.; Anderson, P.M.

1987-05-01

102

CCMR: Investigation of Potential Buffer Solutions and Concentrations for an Electrochemical Microfluidic Biosensor  

NSDL National Science Digital Library

Biosensors are analytical devices that are being used to detect a variety of analytes including pathogens via antibody recognition. Liposomes have been used in the Baeumner research group for signal generation and amplification. In one detection strategy, electrochemical signals are being reported by entrapping a redox couple in the inner cavity of the liposomes and releasing them upon detection of the pathogen. The main task of this research was the optimization of a buffer system that can be used for the entrapment of the redox couple and does not inhibit the oxidation and reduction reactions on a gold electrode. Potassium ferrihexacyanide and potassium ferrohexacyanide (ferri/ferrohexacyanide) were used as redox couple and dissolved in 0.01M bicarbonate buffer, pH 7.0; 0.01M and 0.1M sodium borate buffers, pH 7.0; and 0.01M and 0.1M phosphate buffers, pH 7.0. The current produced by flowing each of these solutions through a 500μm long by 50μm deep channel in polydimethylsiloxane (PDMS) over the interdigitated ultramicroelectrode array (IDUA) was measured using amperometry. The resulting signal peaks created by the redox cycling of ferri/ferrohexacyanide on the electrode were compared. A 10μM solution of ferri/ferrohexacyanide gave signals of 0.44nA in 0.01M phosphate buffer, 0.41nA in sodium borate, 0.37nA in sodium borate diluted in phosphate buffer, and 0.04nA in 0.01M bicarbonate. Since the phosphate buffer cannot be used for liposome synthesis, it was determined that the sodium borate buffer might be the best alternative.

Wiles, Laura K.

2009-08-15

103

Effect of Sodium Bicarbonate Preloading on Ischemic Renal Failure  

Microsoft Academic Search

Rats pretreated with sodium bicarbonate were functionally protected from the damage of bilateral renal artery occlusion. The rise in serum creatinine (day 1 minus day 0) during the first 24 h after ischemia was 2.88 ± 0.28 mg% in the bicarbonate-loaded animals versus 3.90 ± 0.26 mg% in their matched controls (p ? 0.01). Pretreatment with acetazolamide produced a similar

James L. Atkins

1986-01-01

104

Effect of bismuth subcitrate on amphibian gastroduodenal bicarbonate secretion  

Microsoft Academic Search

The ulcer healing and cytoprotective properties of colloidal bismuth (De-Nol) are well established although its mode of action is unclear. We have examined the action of bismuth subcitrate, the active ingredient of De-Nol, on gastroduodenal bicarbonate secretion by isolated amphibian mucosa. Addition of bismuth subcitrate (10(-6) to 10(-4) M) to the luminal solution produced a dose dependent increase in bicarbonate

C J Shorrock; J R Crampton; L C Gibbons; W D Rees

1989-01-01

105

The Bicarbonate Transporter Is Essential for Bacillus anthracis Lethality  

Microsoft Academic Search

In the pathogenic bacterium Bacillus anthracis, virulence requires induced expression of the anthrax toxin and capsule genes. Elevated CO2\\/bicarbonate levels, an indicator of the host environment, provide a signal ex vivo to increase expression of virulence factors, but the mechanism underlying induction and its relevance in vivo are unknown. We identified a previously uncharacterized ABC transporter (BAS2714-12) similar to bicarbonate

Adam C. Wilson; Magali Soyer; James A. Hoch; Marta Perego

2008-01-01

106

Proteins contribute insignificantly to the intrinsic buffering capacity of yeast cytoplasm  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer We predicted buffering capacity of yeast proteome from protein abundance data. Black-Right-Pointing-Pointer We measured total buffering capacity of yeast cytoplasm. Black-Right-Pointing-Pointer We showed that proteins contribute insignificantly to buffering capacity. -- Abstract: Intracellular pH is maintained by a combination of the passive buffering of cytoplasmic dissociable compounds and several active systems. Over the years, a large portion of and possibly most of the cell's intrinsic (i.e., passive non-bicarbonate) buffering effect was attributed to proteins, both in higher organisms and in yeast. This attribution was not surprising, given that the concentration of proteins with multiple protonable/deprotonable groups in the cell exceeds the concentration of free protons by a few orders of magnitude. Using data from both high-throughput experiments and in vitro laboratory experiments, we tested this concept. We assessed the buffering capacity of the yeast proteome using protein abundance data and compared it to our own titration of yeast cytoplasm. We showed that the protein contribution is less than 1% of the total intracellular buffering capacity. As confirmed with NMR measurements, inorganic phosphates play a crucial role in the process. These findings also shed a new light on the role of proteomes in maintaining intracellular pH. The contribution of proteins to the intrinsic buffering capacity is negligible, and proteins might act only as a recipient of signals for changes in pH.

Poznanski, Jaroslaw [Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw (Poland)] [Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw (Poland); Szczesny, Pawel [Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw (Poland) [Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw (Poland); Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw (Poland); Ruszczynska, Katarzyna [Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw (Poland)] [Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw (Poland); Zielenkiewicz, Piotr [Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw (Poland) [Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw (Poland); Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw (Poland); Paczek, Leszek, E-mail: leszek.paczek@wum.edu.pl [Department of Immunology, Transplantology and Internal Medicine, Warsaw Medical University, Warsaw (Poland)] [Department of Immunology, Transplantology and Internal Medicine, Warsaw Medical University, Warsaw (Poland)

2013-01-11

107

Valuation of forested buffers  

NASA Astrophysics Data System (ADS)

The research concentrated on two fronts: (1) defining relationships between land use complex and nitrate and sediment concentrations; and (2) developing a method for assessing the extent of potential and water quality improvements available through land management options and their associated costs. In this work, selected basins of the Fish River (Alabama) were delineated, land use/land cover types were classified, and "contributing zones" were delineated using Geographic Information System (GIS) and Remote Sensing (RS) analytical tools. Water samples collected from these basins were analyzed for their nutrient contents. Based on measured nitrate and sediment concentrations in basin streams, a linkage model was developed. This linkage model relates land use/land cover with the pollution levels in the stream. The linkage model was evaluated at three different scales: (1) the basin scale; (2) the contributing zone scale; and (3) the stream buffer/riparian zone scale. The contributing zone linkage model suggests that forests act as a sink or transformation zone. Residential/urban/built-up areas were identified as the strongest contributors of nitrate in the contributing zones model and active agriculture was identified as the second largest contributor. Regression results for the "land use/land cover diversity" model (stream buffer/riparian zone scale) suggest that areas that are close (adjacent) to the stream and any disturbances in these areas will have major impacts on stream water quality. The economic model suggests the value of retiring lands from agricultural land uses to forested buffers varies from 0 to 3067 per hectare, depending on the types of crops currently grown. Along with conversion costs, this land value forms the basis for estimates of the costs of land management options for improving (or maintaining) water quality throughout the study area. The model also shows the importance of stream-side management zones, which are key to maintenance of stream water quality.

Basnyat, Prakash

108

Bicarbonate attenuates arterial desaturation during maximal exercise in humans.  

PubMed

The contribution of pH to exercise-induced arterial O2 desaturation was evaluated by intravenous infusion of sodium bicarbonate (Bic, 1 M; 200-350 ml) or an equal volume of saline (Sal; 1 M) at a constant infusion rate during a "2,000-m" maximal ergometer row in five male oarsmen. Blood-gas variables were corrected to the increase in blood temperature from 36.5 +/- 0.3 to 38.9 +/- 0.1 degrees C (P < 0.05; means +/- SE), which was established in a pilot study. During Sal exercise, pH decreased from 7.42 +/- 0.01 at rest to 7.07 +/- 0.02 but only to 7.34 +/- 0.02 (P < 0.05) during the Bic trial. Arterial PO2 was reduced from 103.1 +/- 0.7 to 88.2 +/- 1.3 Torr during exercise with Sal, and this reduction was not significantly affected by Bic. Arterial O2 saturation was 97.5 +/- 0.2% at rest and decreased to 89.0 +/- 0.7% during Sal exercise but only to 94.1 +/- 1% with Bic (P < 0.05). Arterial PCO2 was not significantly changed from resting values in the last minute of Sal exercise, but in the Bic trial it increased from 40.5 +/- 0.5 to 45.9 +/- 2.0 Torr (P < 0.05). Pulmonary ventilation was lowered during exercise with Bic (155 +/- 14 vs. 142 +/- 13 l/min; P < 0.05), but the exercise-induced increase in the difference between the end-tidal O2 pressure and arterial PO2 was similar in the two trials. Also, pulmonary O2 uptake and changes in muscle oxygenation as determined by near-infrared spectrophotometry during exercise were similar. The enlarged blood-buffering capacity after infusion of Bic attenuated acidosis and in turn arterial desaturation during maximal exercise. PMID:12133884

Nielsen, Henning B; Bredmose, Per P; Strømstad, Morten; Volianitis, Stefanos; Quistorff, Bjørn; Secher, Niels H

2002-08-01

109

Optimization of the capillary zone electrophoresis loading limit and resolution of proteins, using triethylamine, ammonium formate and acidic pH  

Microsoft Academic Search

Capillary zone electrophoresis (CZE) of five model proteins (lysozyme, myoglobin, ribonuclease A, ?-lactalbumin, and trypsinogen), using ammonium formate as the electrophoretic buffer and triethylamine (TEA) as a buffer additive at pH 2.5, was used for protein separation. The electrophoretic behavior of these proteins was examined with respect to various concentrations (10–40 mM) of TEA and of ammonium formate. Based on

Huey G. Lee; Dominic M. Desiderio

1997-01-01

110

Ammonium generation during SRAT cycle  

SciTech Connect

During the IDMS noble-metal demonstration runs ammonium nitrate deposition was found in the vessel vent system of the feed preparation area. In the bench-scale experiments of studying the hydrogen generation during the sludge treatment cycle, ammonium ion production was also monitored. It was found that: During a simulation of the DWPF Cold Chemical Runs SRAT cycle no detectable amount of ammonium ions was generated when treating a non-noble-metal containing sludge simulant according to the nitric acid flowsheet. Ammonium ions were generated during the SRAT-SME cycle when treating the noble-metal containing sludge with either formic acid or nitric acid/late-washing PHA. This is due to the reaction between formic acid and nitrate catalyzed by the noble metals in the sludge simulant. Ammonium ion production closely followed the hydrogen evolution from the catalytic decomposition of formic acid. This report summarizes the results of the production of ammonia during the SRAT cycle.

Hsu, C.W.

1992-10-13

111

Effect of sodium bicarbonate ingestion upon repeated sprints.  

PubMed Central

The purpose of the study was to assess the effect of sodium bicarbonate ingestion upon repeated bouts of intensive short duration exercise. Twenty-three subjects participated in the investigation (8 females and 15 males, age 21.4 +/- 2.3, mean +/- sd). Subjects completed six trials; three following the ingestion of sodium bicarbonate (300 mg/kg body weight) and three following the ingestion of a placebo (8 g sodium chloride). Each trial consisted of ten ten-second sprints on a cycle ergometer with 50 seconds recovery between each sprint. 'Peak power' and 'average power output' during each ten second sprint was measured from the flywheel of the ergometer using a light-sensitive monitor (Cranlea) linked to a BBC microcomputer. The power outputs recorded during each ten-second sprint of the bicarbonate trials were then compared with those recorded during the corresponding sprint of the placebo trials. The bicarbonate trials produced higher mean 'average power' outputs in all ten of the ten-second sprints, with the difference in 'average power' output being statistically significant in eight of these (p less than 0.05). The results also revealed that the difference in the 'average power' outputs attained during the bicarbonate and placebo trials increased as the number of sprint repetitions increased (p less than 0.01). 'Peak power' output was also greater in the bicarbonate trials with it being significantly higher (p less than 0.001) during the final ten-second sprint. It was concluded that during exercise consisting of repeated, short-duration sprints, power output was enhanced following the ingestion of sodium bicarbonate, (300 mg/kg body weight).

Lavender, G; Bird, S R

1989-01-01

112

Ammonium Regulation in Aspergillus nidulans  

PubMed Central

l-Glutamate uptake, thiourea uptake, and methylammonium uptake and the intracellular ammonium concentration were measured in wild-type and mutant cells of Aspergillus nidulans held in various concentrations of ammonium and urea. The levels of l-glutamate uptake, thiourea uptake, nitrate reductase, and hypoxanthine dehydrogenase activity are determined by the extracellular ammonium concentration. The level of methylammonium uptake is determined by the intracellular ammonium concentration. The uptake and enzyme characteristics of the ammonium-derepressed mutants, meaA8, meaB6, DER3, amrA1, xprD1, and gdhA1, are described. The gdhA mutants lack normal nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase (NADP-GDH) activity and are derepressed with respect to both external and internal ammonium. The other mutant classes are derepressed only with respect to external ammonium. The mutants meaA8, DER3, amrA1, and xprD1 have low levels of one or more of the l-glutamate, thiourea, and methylammonium uptake systems. A model for ammonium regulation in A. nidulans is put forward which suggests: (i) NADP-GDH located in the cell membrane complexes with extracellular ammonium. This first regulatory complex determines the level of l-glutamate uptake, thiourea uptake, nitrate reductase, and xanthine dehydrogenase by repression or inhibition, or both. (ii) NADP-GDH also complexes with intracellular ammonium. This second and different form of regulatory complex determines the level of methylammonium uptake by repression or inhibition, or both.

Pateman, J. A.; Kinghorn, J. R.; Dunn, Etta; Forbes, E.

1973-01-01

113

76 FR 70366 - Ammonium Nitrate Security Program  

Federal Register 2010, 2011, 2012, 2013

...NPRM for the Ammonium Nitrate Security Program. The agenda for the public...Department's Ammonium Nitrate Security Program Web site, at http://www.dhs...programs/ammonium-nitrate-security-program.shtm. This...

2011-11-14

114

76 FR 62311 - Ammonium Nitrate Security Program  

Federal Register 2010, 2011, 2012, 2013

...NPRM) for the Ammonium Nitrate Security Program. The agenda for the public...Department's Ammonium Nitrate Security Program Web site in mid-October at http...programs/ammonium-nitrate-security-program.shtm. Each...

2011-10-07

115

EnFET for urea determination in biological fluids using ammonium ion detection  

NASA Astrophysics Data System (ADS)

In this paper a method of urease immobilization on the surface of the Siloprene membrane of the ammonium ion sensitive ChemFET is presented. The usability of the sensor for determination of urea in solutions at pH typical for biological fluids (pH 6 to pH 7.5) has been investigated. Due to the fact that the sensor exhibits high sensitivity to samples of low buffer capacity, the method of preliminary sample treatment, consisting in addition of buffers at adequate buffer capacity was developed. The sensors were tested in dialysate and blood plasma.

Dawgul, Marek; Trybun, Tomasz; Pijanowska, Dorota G.; Torbicz, Wladyslaw

2003-09-01

116

Role of calcium signaling in epithelial bicarbonate secretion.  

PubMed

Transepithelial bicarbonate secretion plays a key role in the maintenance of fluid and protein secretion from epithelial cells and the protection of the epithelial cell surface from various pathogens. Epithelial bicarbonate secretion is mainly under the control of cAMP and calcium signaling. While the physiological roles and molecular mechanisms of cAMP-induced bicarbonate secretion are relatively well defined, those induced by calcium signaling remain poorly understood in most epithelia. The present review summarizes the current status of knowledge on the role of calcium signaling in epithelial bicarbonate secretion. Specifically, this review introduces how cytosolic calcium signaling can increase bicarbonate secretion by regulating membrane transport proteins and how it synergizes with cAMP-induced mechanisms in epithelial cells. In addition, tissue-specific variations in the pancreas, salivary glands, intestines, bile ducts, and airways are discussed. We hope that the present report will stimulate further research into this important topic. These studies will provide the basis for future medicines for a wide spectrum of epithelial disorders including cystic fibrosis, Sjögren's syndrome, and chronic pancreatitis. PMID:24598807

Jung, Jinsei; Lee, Min Goo

2014-06-01

117

A Radiochemical Microtechnique for the Determination of Traces of Ammonia And Ammonium Salts  

Microsoft Academic Search

A radiochemical procedure for the determination of traces of ammonia and ammonium ions in aqueous solutions is presented. In a buffered medium ammonia is precipita- 203 203 ted by Hg(II) as Hg2NCl. If the same amount of the radioreagent is always employed, a negative linear correlation is obtained between the amount of ammonia to be determined and the activity of

A. Teckentrup; D. Klockow

1980-01-01

118

Dimethyl Dioctadecyl Ammonium Bromide (DDA)Induced Arthritis in Rats: a Model of Experimental Arthritis  

Microsoft Academic Search

A single intradermal injection of 2mg of dimethyl dioctadecyl ammonium bromide (DDA) in phosphate buffered saline (PBS) could induce polyarthritis in both LEW and DA rats with low incidence and severity whereas 2mg of DDA in incomplete Freund's adjuvant (IFA) could induce very severe polyarthritis with 100% incidence in LEW rats. Histology of DDA-induced arthritis (DIA) revealed cellular infiltration, synovial

Li Zhang; Cong Long Zheng; Osamu Tokunaga; Osamu Kohashi

2000-01-01

119

The buffering capacity of crystalloid and colloid resuscitation solutions.  

PubMed

The buffering capacities of common colloid and crystalloid resuscitation solutions were compared in vitro. An equal volume of each resuscitation solution was titrated above and below its initial pH with 0.14 N sodium hydroxide or 0.11 N hydrochloric acid. The volume (+/- S.D.) of titration solution necessary to lower the pH one unit (7.1-6.1) in these solutions was less than 0.5 ml for normal saline, less than 0.5 ml for Ringer's lactate, 1.9 +/- 0.1 ml for Plasmalyte-A, 2.0 +/- 0.23 ml for Plasmalyte-R, 8.8 +/- 0.17 ml for human serum albumin (HSA), 45 +/- 2.2 ml for human fresh frozen plasma (FFP), and 50 +/- 6.6 ml for swine FFP. With the method of this in vitro study, human fresh frozen plasma was 25-50 times better as an acid buffer than the crystalloid solutions and approx. 5 times better than human serum albumin (HSA). On an equal volume basis, it was the superior resuscitation solution as a buffer, probably because of combined bicarbonate and protein content. PMID:2989996

Traverso, L W; Medina, F; Bolin, R B

1985-03-01

120

Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters  

Microsoft Academic Search

The concept of anaerobic ammonium oxidation (ANAMMOX) is presently of great interest. The functional bacteria belonging to\\u000a the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile, the ANAMMOX is equally valuable\\u000a in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic\\u000a nitrogen removal over nitrite (CANON) have been developed, and lab-scale experiments proved that both

Lei Zhang; Ping Zheng; Chong-jian Tang; Jin Ren-cun

2008-01-01

121

Metabolism of nitrate- and ammonium-nitrogen absorbed from ammonium nitrate and ammonium sulfate in the tobacco plant  

Microsoft Academic Search

In water culture experiments with tobacco plants, ammonium nitrate has been generally used as a nitrogen source. In a comparison among various nitrogen sources for water cultured tobacco, better growth has been obtained with ammonium nitrate than with sodium nitrate and ammonium sulfate (1). It has been shown that both ammonium- and nitrate-nitrogen are simultaneously absorbed by the tobacco plant

Daisuke Yoshida

1966-01-01

122

Control of Proximal Bicarbonate Reabsorption in Normal and Acidotic Rats  

PubMed Central

This free-flow micropuncture study examined the dependence of bicarbonate reabsorption in the rat superficial proximal convoluted tubule to changes in filtered bicarbonate load, and thereby the contribution of the proximal tubule to the whole kidney's response to such changes. The independent effects of extracellular fluid (ECF) volume expansion and of acidosis on proximal bicarbonate reabsorption were also examined. When the plasma volume contraction incurred by the micropuncture preparatory surgery was corrected by isoncotic plasma infusion (?1.3% body wt), single nephron glomerular filtration rate (SNGFR), and the filtered total CO2 load increased by 50%. Absolute proximal reabsorption of total CO2 (measured by microcalorimetry) increased by 30%, from 808±47 during volume contraction to 1,081±57 pmol/min·g kidney wt after plasma repletion, as fractional total CO2 reabsorption decreased from 0.90 to 0.77. Aortic constriction in these plasma-repleted rats returned the filtered load and reabsorption of total CO2 to the previous volume contracted levels. In other animals isohydric ECF expansion with plasma (5% body wt) or Ringer's solution (10% body wt), or both, produced no further diminution in fractional proximal total CO2 reabsorption (0.76-0.81). Metabolic acidosis was associated with very high fractional proximal total CO2 reabsorptive rates of 0.82 to 0.91 over a wide range of SNGFR and ECF volumes. At a single level of SNGFR, end-proximal total CO2 concentration progressively decreased from 5.6±0.5 to 1.6 ±0.2 mM as arterial pH fell from 7.4 to 7.1. Expansion of ECF volume in the acidotic rats did not inhibit the ability of the proximal tubule to lower end-proximal total CO2 concentrations to minimal levels. In conclusion, bicarbonate reabsorption in the superficial proximal convoluted tubule is highly load-dependent (75-90%) in normal and acidotic rats. No inhibitory effect of ECF volume per se on proximal bicarbonate reabsorption, independent of altering the filtered bicarbonate load, could be discerned. Acidosis enabled the end-proximal luminal bicarbonate concentration to fall below normal values and reduced distal bicarbonate delivery.

Cogan, Martin G.; Maddox, David A.; Lucci, Marjory S.; Rector, Floyd C.; Mueller, Monika R.; Wong, Kenneth R.

1979-01-01

123

Control of proximal bicarbonate reabsorption in normal and acidotic rats.  

PubMed

This free-flow micropuncture study examined the dependence of bicarbonate reabsorption in the rat superficial proximal convoluted tubule to changes in filtered bicarbonate load, and thereby the contribution of the proximal tubule to the whole kidney's response to such changes. The independent effects of extracellular fluid (ECF) volume expansion and of acidosis on proximal bicarbonate reabsorption were also examined. When the plasma volume contraction incurred by the micropuncture preparatory surgery was corrected by isoncotic plasma infusion ( congruent with1.3% body wt), single nephron glomerular filtration rate (SNGFR), and the filtered total CO(2) load increased by 50%. Absolute proximal reabsorption of total CO(2) (measured by microcalorimetry) increased by 30%, from 808+/-47 during volume contraction to 1,081+/-57 pmol/min.g kidney wt after plasma repletion, as fractional total CO(2) reabsorption decreased from 0.90 to 0.77. Aortic constriction in these plasma-repleted rats returned the filtered load and reabsorption of total CO(2) to the previous volume contracted levels. In other animals isohydric ECF expansion with plasma (5% body wt) or Ringer's solution (10% body wt), or both, produced no further diminution in fractional proximal total CO(2) reabsorption (0.76-0.81). Metabolic acidosis was associated with very high fractional proximal total CO(2) reabsorptive rates of 0.82 to 0.91 over a wide range of SNGFR and ECF volumes. At a single level of SNGFR, end-proximal total CO(2) concentration progressively decreased from 5.6+/-0.5 to 1.6 +/-0.2 mM as arterial pH fell from 7.4 to 7.1. Expansion of ECF volume in the acidotic rats did not inhibit the ability of the proximal tubule to lower end-proximal total CO(2) concentrations to minimal levels. In conclusion, bicarbonate reabsorption in the superficial proximal convoluted tubule is highly load-dependent (75-90%) in normal and acidotic rats. No inhibitory effect of ECF volume per se on proximal bicarbonate reabsorption, independent of altering the filtered bicarbonate load, could be discerned. Acidosis enabled the end-proximal luminal bicarbonate concentration to fall below normal values and reduced distal bicarbonate delivery. PMID:500804

Cogan, M G; Maddox, D A; Lucci, M S; Rector, F C

1979-11-01

124

High performance ammonium nitrate propellant  

NASA Technical Reports Server (NTRS)

A high performance propellant having greatly reduced hydrogen chloride emission is presented. It is comprised of: (1) a minor amount of hydrocarbon binder (10-15%), (2) at least 85% solids including ammonium nitrate as the primary oxidizer (about 40% to 70%), (3) a significant amount (5-25%) powdered metal fuel, such as aluminum, (4) a small amount (5-25%) of ammonium perchlorate as a supplementary oxidizer, and (5) optionally a small amount (0-20%) of a nitramine.

Anderson, F. A. (inventor)

1979-01-01

125

The anaerobic oxidation of ammonium.  

PubMed

From recent research it has become clear that at least two different possibilities for anaerobic ammonium oxidation exist in nature. 'Aerobic' ammonium oxidizers like Nitrosomonas eutropha were observed to reduce nitrite or nitrogen dioxide with hydroxylamine or ammonium as electron donor under anoxic conditions. The maximum rate for anaerobic ammonium oxidation was about 2 nmol NH4+ min-1 (mg protein)-1 using nitrogen dioxide as electron acceptor. This reaction, which may involve NO as an intermediate, is thought to generate energy sufficient for survival under anoxic conditions, but not for growth. A novel obligately anaerobic ammonium oxidation (Anammox) process was recently discovered in a denitrifying pilot plant reactor. From this system, a highly enriched microbial community with one dominating peculiar autotrophic organism was obtained. With nitrite as electron acceptor a maximum specific oxidation rate of 55 nmol NH4+ min-1 (mg protein)-1 was determined. Although this reaction is 25-fold faster than in Nitrosomonas, it allowed growth at a rate of only 0.003 h-1 (doubling time 11 days). 15N labeling studies showed that hydroxylamine and hydrazine were important intermediates in this new process. A novel type of hydroxylamine oxidoreductase containing an unusual P468 cytochrome has been purified from the Anammox culture. Microsensor studies have shown that at the oxic/anoxic interface of many ecosystems nitrite and ammonia occur in the absence of oxygen. In addition, the number of reports on unaccounted high nitrogen losses in wastewater treatment is gradually increasing, indicating that anaerobic ammonium oxidation may be more widespread than previously assumed. The recently developed nitrification systems in which oxidation of nitrite to nitrate is prevented form an ideal partner for the Anammox process. The combination of these partial nitrification and Anammox processes remains a challenge for future application in the removal of ammonium from wastewater with high ammonium concentrations. PMID:9990725

Jetten, M S; Strous, M; van de Pas-Schoonen, K T; Schalk, J; van Dongen, U G; van de Graaf, A A; Logemann, S; Muyzer, G; van Loosdrecht, M C; Kuenen, J G

1998-12-01

126

Oracle Log Buffer Queueing  

SciTech Connect

The purpose of this document is to investigate Oracle database log buffer queuing and its affect on the ability to load data using a specialized data loading system. Experiments were carried out on a Linux system using an Oracle 9.2 database. Previous experiments on a Sun 4800 running Solaris had shown that 100,000 entities per minute was an achievable rate. The question was then asked, can we do this on Linux, and where are the bottlenecks? A secondary question was also lurking, how can the loading be further scaled to handle even higher throughput requirements? Testing was conducted using a Dell PowerEdge 6650 server with four CPUs and a Dell PowerVault 220s RAID array with 14 36GB drives and 128 MB of cache. Oracle Enterprise Edition 9.2.0.4 was used for the database and Red Hat Linux Advanced Server 2.1 was used for the operating system. This document will detail the maximum observed throughputs using the same test suite that was used for the Sun tests. A detailed description of the testing performed along with an analysis of bottlenecks encountered will be made. Issues related to Oracle and Linux will also be detailed and some recommendations based on the findings.

Rivenes, A S

2004-12-08

127

Mechanisms of buffer therapy resistance  

PubMed Central

Many studies have shown that the acidity of solid tumors contributes to local invasion and metastasis. Oral pH buffers can specifically neutralize the acidic pH of tumors and reduce the incidence of local invasion and metastatic formation in multiple murine models. However, this effect is not universal as we have previously observed that metastasis is not inhibited by buffers in some tumor models, regardless of buffer used. B16-F10 (murine melanoma), LL/2 (murine lung) and HCT116 (human colon) tumors are resistant to treatment with lysine buffer therapy, whereas metastasis is potently inhibited by lysine buffers in MDA-MB-231 (human breast) and PC3M (human prostate) tumors. In the current work, we confirmed that sensitive cells utilized a pH-dependent mechanism for successful metastasis supported by a highly glycolytic phenotype that acidifies the local tumor microenvironment resulting in morphological changes. In contrast, buffer-resistant cell lines exhibited a pH-independent metastatic mechanism involving constitutive secretion of matrix degrading proteases without elevated glycolysis. These results have identified two distinct mechanisms of experimental metastasis, one of which is pH-dependent (buffer therapy sensitive cells) and one which is pH-independent (buffer therapy resistant cells). Further characterization of these models has potential for therapeutic benefit.

Bailey, Kate M.; Wojtkowiak, Jonathan W.; Cornnell, Heather H.; Ribeiro, Maria C.; Balagurunathan, Yoganand; Hashim, Arig Ibrahim; Gillies, Robert J.

2014-01-01

128

Facilitated Lactate Transport by MCT1 when Coexpressed with the Sodium Bicarbonate Cotransporter (NBC) in Xenopus Oocytes  

PubMed Central

Monocarboxylate transporters (MCT) and sodium-bicarbonate cotransporters (NBC) transport acid/base equivalents and coexist in many epithelial and glial cells. In nervous systems, the electroneutral MCT1 isoform cotransports lactate and other monocarboxylates with H+, and is believed to be involved in the shuttling of energy-rich substrates between astrocytes and neurons. The NBC cotransports bicarbonate with sodium and generates a membrane current. We have expressed these transporter proteins, cloned from rat brain (MCT1) and human kidney (NBC), alone and together, by injecting the cRNA into oocytes of the frog Xenopus laevis, and measured intracellular pH changes and membrane currents under voltage-clamp with intracellular microelectrodes, and radiolabeled lactate uptake into the oocytes. We determined the cytosolic buffer capacity, the H+ and lactate fluxes as induced by 3 and 10 mM lactate in oocytes expressing MCT1 and/or NBC, and in water-injected oocytes, in salines buffered with 5 mM HEPES alone or with 5% CO2/10 mM HCO3? (pH 7.0). In MCT1 + NBC- but not in MCT1- or NBC-expressing oocytes, lactate activated a Na+- and HCO3?-dependent membrane current, indicating that lactate/H+ cotransport via MCT1, due to the induced pH change, stimulates NBC activity. Lactate/H+ cotransport by MCT1 was increased about twofold when MCT1 was expressed together with NBC. Our results suggest that the facilitation of MCT1 transport activity is mainly due to the increase in apparent buffer capacity contributed by the NBC, and thereby suppresses the build-up of intracellular H+ during the influx of lactate/H+, which would reduce MCT1 activity. Hence these membrane transporters functionally cooperate and are able to increase ion/metabolite transport activity.

Becker, Holger M.; Broer, Stefan; Deitmer, Joachim W.

2004-01-01

129

Capillary electrophoresis with detection by inverse UV spectroscopy and electrospray mass spectrometry for the examination of quaternary ammonium herbicides  

Microsoft Academic Search

The value of capillary electrophoresis (CE) and combined capillary electrophoresis-electrospray mass spectrometry (CE-ES-MS) for the analysis of simple quaternary ammonium ions, including herbicides, has been assessed. Choline, chlormequat, known contaminants of their formulation products, and some other small ammonium cations have been examined. Lacking a chromophore, the cations were detected by inverse UV absorption utilizing a buffer containing creatinine as

Darren Wycherley; Malcolm E. Rose; Kevin Giles; Therese M. Hutton; Duncan A. Rimmer

1996-01-01

130

Adverse Effect of Ammonium Salts on the Antibacterial Activity of Paraformaldehyde Solutions  

PubMed Central

The antibacterial activity of aqueous solutions of paraformaldehyde in concentrations from 0.1 to 0.4% (w/v) is bacteriostatic rather than bactericidal in the presence or absence of ammonium chloride. The presence of ammonium chloride significantly lengthened the time of exposure to paraformaldehyde necessary for inhibition of growth of the test organism (Staphylococcus aureus FDA 209) when unbuffered solutions were used. Elevation of the pH of the reacting mixture of paraformaldehyde and ammonium chloride by partial buffering lengthened the time of exposure necessary for inhibition of growth of the test organism. Decrease of antibacterial activity was concomitant with the disappearance of paraformaldehyde from the reacting mixture. The reaction of paraformaldehyde with ammonium chloride was rapid at room temperature (25 C) and at pH levels near neutrality. The fate of the reacting paraformaldehyde, including the possibility of the formation of hexamethylenetetramine or methylenimine, is discussed with particular reference to loss of antibacterial activity.

Myers, G. E.; McCready, R. G. L.

1963-01-01

131

Removal of co-present chromate and arsenate by zero-valent iron in groundwater with humic acid and bicarbonate.  

PubMed

The interactions of co-present Cr(VI) and As(V), and the influences of humic acid and bicarbonate in the process of Cr(VI) and As(V) removal by Fe(0) were investigated in a batch setting using simulated groundwater with 5 mM NaCl, 1 mM Na(2)SO(4), and 0.8 mM CaCl(2) as background electrolytes at an initial pH value of 7. Cr(VI) and As(V) were observed to be subject to different impacts induced by co-existing As(V) or Cr(VI), humic acid and bicarbonate, originating from their distinct removal mechanisms by Fe(0). Cr(VI) removal is a reduction-dominated process, whereas As(V) removal principally involves adsorption onto iron corrosion products. Experimental results showed that Cr(VI) removal was not affected by the presence of As(V) and humic acid. However, As(V) removal appeared to be inhibited by co-present Cr(VI). When the Cr(VI) concentration was 2, 5, and 10 mg/L, in the absence of humic acid and bicarbonate, As(V) removal rate constants were decreased by 27.9%, 49.0%, and 61.2%, respectively, which probably resulted from competition between Cr(VI) and As(V) for adsorption sites of the iron corrosion products. Furthermore, the presence of humic acid significantly varied As(V) removal kinetics by delaying the formation and aggregation of iron hydroxides due to the formation of soluble Fe-humate complexes and stably dispersed fine iron hydroxides colloids. In the presence of bicarbonate, both Cr(VI) and As(V) removal was increased and the inhibitory effect of Cr(VI) on As(V) removal was suppressed, resulting from the buffering effects and the promoted iron corrosion induced by bicarbonate, and the formation of CaCO(3) in solution, which enhanced As(V) adsorption. PMID:19321187

Liu, Tongzhou; Rao, Pinhua; Mak, Mark S H; Wang, Peng; Lo, Irene M C

2009-05-01

132

In-situ leaching of South Texas uranium ores - 2. Oxidative removal of adsorbed ammonium ions with sodium hypochlorite  

SciTech Connect

This paper reports a laboratory study of the oxidative destruction, by sodium hypochlorite, of ammonium ions adsorbed on relatively reduced South Texas uranium ore. Included are an assessment of reaction stoichiometry, determination of some major reaction pathways and side reactions, and identification of several intermediates. Adsorbed ammonium ions were completely removed by 0.5% sodium hypochlorite with the concentration of ammonia in the effluent falling to a very low value after 10-15 pore volumes of the oxidant. Substantial quantities of sulfate, reflecting oxidation of sulfide minerals such as pyrite, were formed. Large amounts of uranium were leached out, and substantial amounts of calcium and magnesium ions were also produced during the pre-saturation with ammonium bicarbonate during the oxidation stage. 28 refs.

Paul, J.M.; Johnson, W.F.; Fletcher, A.; Venuto, P.B.

1981-01-01

133

Improving Eggshell Quality at High Temperatures with Dietary Sodium Bicarbonate  

Microsoft Academic Search

Two experiments were conducted that confirmed the hypothesis that a dietary bicarbonate supplement will improve eggshell quality in hens at high temperatures as long as feed is consumed during the period of eggshell formation. End-of-lay hens were maintained on continuous light at temperatures of 30 and 35 C. Individual egg weights and shell quality measures for each hen were calculated

D. BALNAVE; S. K. MUHEEREZA

134

Hormonal regulation of bicarbonate secretion in the biliary epithelium.  

PubMed Central

Bicarbonate excretion in bile is a major function of the biliary epithelium. It is driven by the apically located Cl-/HCO3- exchanger which is functionally coupled with a cAMP-dependent Cl- channel (CFTR). A number of hormones and/or neuropeptides with different mechanisms and at different intracellular levels regulate, in concert, the processes underlying bicarbonate excretion in the biliary epithelium. Secretin induces a bicarbonate rich choleresis by stimulating the activity of the Cl-/HCO3- exchanger by cAMP and protein kinase A mediated phosphorylation of CFTR regulatory domain. Protein phosphatase 1/2A are involved in the run-down of secretory stimulus after secretin removal. Acetylcholine potentiates secretin-choleresis by inducing a Ca(++)-calcineurin mediated "sensitization" of adenyl cyclase to secretin. Bombesin and vasoactive intestinal peptide also enhance the Cl-/HCO3- exchanger activity, but the intracellular signal transduction pathway has not yet been defined. Somatostatin and gastrin inhibit basal and/or secretin-stimulated bicarbonate excretion by down-regulating the secretin receptor and decreasing cAMP intracellular levels induced by secretin.

Alvaro, D.; Gigliozzi, A.; Fraioli, F.; Romeo, R.; Papa, E.; Delle Monache, M.; Capocaccia, L.

1997-01-01

135

Sodium Bicarbonate for the Treatment of Lactic Acidosis  

Microsoft Academic Search

Lactic acidosis often challenges the intensivist and is associated with a strikingly high mortality. Treatment involves discerning and correcting its underlying cause, ensuring adequate oxygen delivery to tissues, reducing oxygen demand through sedation and mechanical ventilation, and (most controversially) attempting to alkalinize the blood with IV sodium bicarbonate. Here we review the literature to answer the following questions: Is a

Sean M. Forsythe; Gregory A. Schmidt

136

Exercise in the Heat. Effects of Saline or Bicarbonate Infusion.  

National Technical Information Service (NTIS)

Adult, male rats (N=17/group, 300-320 g, physically untrained) were exercised (9.14 m/min) in the heat (35 C) to hyperthermic exhaustion (Tre = 43 C) after infusion of 2 ml of 7.5% sodium bicarbonate (BIC) or 2 ml of 0.9% sodium chloride (SAL). BIC or SAL...

R. P. Francesconi R. W. Hubbard

1983-01-01

137

Haemodynamic consequences of changing bicarbonate and calcium concentrations in haemodialysis fluids  

Microsoft Academic Search

Background. In a previous study we demonstrated that mild metabolic alkalosis resulting from standard bicarbon- ate haemodialysis induces hypotension. In this study, we have further investigated the changes in systemic haemo- dynamics induced by bicarbonate and calcium, using non- invasive procedures. Methods. In a randomized controlled trial with a single- blind, crossover design, we sequentially changed the dialysate bicarbonate and

Luca Gabutti; Giorgia Bianchi; Davide Soldini; Claudio Marone; Michel Burnier

138

On the influence of extracellular fluid volume expansion on bicarbonate reabsorption in the rat.  

PubMed

Bicarbonate reabsorption is classically regarded as a rate-limited process characterized by saturation kinetics. The tubular maximum (Tm), however, varies with glomerular filtration rate. Thus bicarbonate reabsorption, in common with sodium reabsorption, is characterized by glomerulo-tubular balance. The examination of bicarbonate reabsorption is accomplished using the bicarbonate titration technique; however, this method in its traditional form leads to marked expansion of extracellular fluid (ECF) volume. The possibility exists, therefore, that glomerulo-tubular balance for bicarbonate is altered by the volume expansion and thus that the classic pattern of reabsorption may actually reflect inhibited bicarbonate reabsorptive capacity. The present studies were performed in rats to examine this possibility. Bicarbonate titration studies were performed in two groups of animals: (a) those in which ECF volume expansion was minimized; and (b) those in which ECF volume expansion was exaggerated. In the first group, no Tm for bicarbonate was observed either in the majority of individual rats studied or in a group plot for all rats studied despite the fact that plasma bicarbonate concentrations were increased to values in excess of 60 mEq/liter. In the second group, a clear Tm was demonstrated both in individual animals and in group data and there was a lowered threshold for the excretion of bicarbonate. The data thus lend support to the view that the "normal" Tm for bicarbonate may actually represent an inhibited level of bicarbonate reabsorption induced by ECF volume expansion. PMID:5822583

Purkerson, M L; Lubowitz, H; White, R W; Bricker, N S

1969-09-01

139

Electrodialysis operation with buffer solution  

DOEpatents

A new method for improving the efficiency of electrodialysis (ED) cells and stacks, in particular those used in chemical synthesis. The process entails adding a buffer solution to the stack for subsequent depletion in the stack during electrolysis. The buffer solution is regenerated continuously after depletion. This buffer process serves to control the hydrogen ion or hydroxide ion concentration so as to protect the active sites of electrodialysis membranes. The process enables electrodialysis processing options for products that are sensitive to pH changes.

Hryn, John N. (Naperville, IL); Daniels, Edward J. (Orland Park, IL); Krumdick, Greg K. (Crete, IL)

2009-12-15

140

Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters*  

PubMed Central

The concept of anaerobic ammonium oxidation (ANAMMOX) is presently of great interest. The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile, the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite (CANON) have been developed, and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control. Successful full-scale practice in the Netherlands will accelerate application of the process in future. This review introduces the microbiology and more focuses on application of the ANAMMOX process.

Zhang, Lei; Zheng, Ping; Tang, Chong-jian; Jin, Ren-cun

2008-01-01

141

Determination of thalidomide in transport buffer for Caco-2 cell monolayers by high-performance liquid chromatography with ultraviolet detection  

Microsoft Academic Search

We report simple validated HPLC methods for the determination of thalidomide in the transport buffer for the human colonic cell line (Caco-2) cell monolayers. An aliquot of 50 ?l of the mixture was injected onto a Spherex C18 column (150×4.6 mm; 5 ?m) at a flow-rate of 0.5 ml\\/min of mobile phase consisting of acetonitrile–10 mM ammonium acetate buffer (24:76,

Shufeng Zhou; Yan Li; Phillip Kestell; James W Paxton

2003-01-01

142

Grocery store baking soda. A source of sodium bicarbonate in the management of chronic metabolic acidosis.  

PubMed

Oral sodium bicarbonate is used to treat metabolic acidosis in patients with renal tubular acidosis. Since infants and young children are unable to swallow tablets, those affected must ingest sodium bicarbonate in a powder or liquid form. Pharmacy-weighed sodium bicarbonate is expensive and inconvenient to obtain; some pharmacists are reluctant to provide it. We determined that the sodium bicarbonate contained in 8-oz boxes of Arm and Hammer Baking Soda was sufficiently constant in weight that, dissolved in water to a given volume, it yielded a quantitatively acceptable therapeutic solution of sodium bicarbonate at a cost of approximately 3 percent of that of pharmacy-weighed sodium bicarbonate. Grocery store baking soda can be a safe, economical, and convenient source of sodium bicarbonate for the treatment of chronic metabolic acidosis in infants and young children. PMID:6319065

Booth, B E; Gates, J; Morris, R C

1984-02-01

143

Isotonic sodium bicarbonate-triggered emodin release from borate stabilized emodin nanoparticles-loaded polymeric microgel films.  

PubMed

Hydrosoluble emodin-borate (EmB) nanoparticles (NPs) were fabricated by a simple solvent exchange method to address emodin's poor water solubility. As the result, negative charges were introduced in the surface of EmB NPs. In addition, layer-by-layer assembled multilayer films containing cation-rich polymeric microgels (named PAHD) and sodium carboxymethyl cellulose (NaCMC) were employed as drug carrier. Anionic EmB can be loaded into the PAHD/CMC multilayer films. The influences of various experimental parameters on cargo capacity of the PAHD/CMC film were studied in detail. The loaded EmB can be released in the form of emodin molecule in presence of isotonic sodium bicarbonate (ISB) solution. Gratifyingly, EmB did not almost release in presence of water, PBS buffer solution, 0.9% normal saline, and 5% glucose solution. PMID:24755249

Wang, Lin; Wang, Xiaohan; Li, Xiaozhou

2014-07-20

144

Grocery Store Baking SodaA Source of Sodium Bicarbonate in the Management of Chronic Metabolic Acidosis  

Microsoft Academic Search

Oral sodium bicarbonate is used to treat metabolic acidosis in patients with renal tubular acidosis. Since infants and young children are unable to swallow tablets, those affected must ingest sodium bicarbonate in a powder or liquid form. Pharmacy-weighed sodium bicarbonate is expensive and inconvenient to obtain; some pharmacists are reluctant to provide it. We determined that the sodium bicarbonate contained

Beverley E. Booth; Jay Gates; R. Curtis Morris

1984-01-01

145

Cyclo-hexyl-ammonium nitrate  

PubMed Central

In the title salt, C6H14N+·NO3 ?, the cyclo­hexyl ring adopts a chair conformation. The ammonium group occupies an equatorial position and the crystal struture is stabilized by inter­molecular N—H?O hydrogen-bonding inter­actions, resulting in a three-dimensional network.

Bagabas, Abdulaziz A.; Aboud, Mohamed F. A.; Shemsi, Ahsan M.; Addurihem, Emad S.; Al-Othman, Zeid A.; Chidan Kumar, C. S.; Fun, Hoong-Kun

2014-01-01

146

Cyclo-hexyl-ammonium nitrate.  

PubMed

In the title salt, C6H14N(+)·NO3 (-), the cyclo-hexyl ring adopts a chair conformation. The ammonium group occupies an equatorial position and the crystal struture is stabilized by inter-molecular N-H?O hydrogen-bonding inter-actions, resulting in a three-dimensional network. PMID:24764971

Bagabas, Abdulaziz A; Aboud, Mohamed F A; Shemsi, Ahsan M; Addurihem, Emad S; Al-Othman, Zeid A; Chidan Kumar, C S; Fun, Hoong-Kun

2014-03-01

147

Buffer gas acquisition and storage  

NASA Astrophysics Data System (ADS)

The acquisition and storage of buffer gases (primarily argon and nitrogen) from the Mars atmosphere provides a valuable resource for blanketing and pressurizing fuel tanks and as a buffer gas for breathing air for manned missions. During the acquisition of carbon dioxide (CO2), whether by sorption bed or cryo-freezer, the accompanying buffer gases build up in the carbon dioxide acquisition system, reduce the flow of CO2 to the bed, and lower system efficiency. It is this build up of buffer gases that provide a convenient source, which must be removed, for efficient capture of CO2. Removal of this buffer gas barrier greatly improves the charging rate of the CO2 acquisition bed and, thereby, maintains the fuel production rates required for a successful mission. Consequently, the acquisition, purification, and storage of these buffer gases are important goals of ISRU plans. Purity of the buffer gases is a concern e.g., if the CO2 freezer operates at 140 K, the composition of the inert gas would be approximately 21 percent CO2, 50 percent nitrogen, and 29 percent argon. Although there are several approaches that could be used, this effort focused on a hollow-fiber membrane (HFM) separation method. This study measured the permeation rates of CO2, nitrogen (N2), and argon (Ar) through a multiple-membrane system and the individual membranes from room temperature to 193 K and 10 kPa to 300 kPa. Concentrations were measured with a gas chromatograph. The end result was data necessary to design a system that could separate CO2, N2, and Ar. .

Parrish, Clyde F.; Lueck, Dale E.; Jennings, Paul A.

2001-02-01

148

Transplastomic integration of a cyanobacterial bicarbonate transporter into tobacco chloroplasts.  

PubMed

Improving global yields of agricultural crops is a complex challenge with evidence indicating benefits in productivity are achieved by enhancing photosynthetic carbon assimilation. Towards improving rates of CO2 capture within leaf chloroplasts, this study shows the versatility of plastome transformation for expressing the Synechococcus PCC7002 BicA bicarbonate transporter within tobacco plastids. Fractionation of chloroplast membranes from transplastomic tob(BicA) lines showed that ~75% of the BicA localized to the thylakoid membranes and ~25% to the chloroplast envelope. BicA levels were highest in young emerging tob(BicA) leaves (0.12 ?mol m(-2), ?7mg m(-2)) accounting for ~0.1% (w/w) of the leaf protein. In these leaves, the molar amount of BicA was 16-fold lower than the abundant thylakoid photosystem II D1 protein (~1.9 ?mol m(-2)) which was comparable to the 9:1 molar ratio of D1:BicA measured in air-grown Synechococcus PCC7002 cells. The BicA produced had no discernible effect on chloroplast ultrastructure, photosynthetic CO2-assimilation rates, carbon isotope discrimination, or growth of the tob(BicA) plants, implying that the bicarbonate transporter had little or no activity. These findings demonstrate the utility of plastome transformation for targeting bicarbonate transporter proteins into the chloroplast membranes without impeding growth or plastid ultrastructure. This study establishes the span of experimental measurements required to verify heterologous bicarbonate transporter function and location in chloroplasts and underscores the need for more detailed understanding of BicA structure and function to identify solutions for enabling its activation and operation in leaf chloroplasts. PMID:24965541

Pengelly, J J L; Förster, B; von Caemmerer, S; Badger, M R; Price, G D; Whitney, S M

2014-07-01

149

Sodium bicarbonate ingestion improves performance in interval swimming  

Microsoft Academic Search

Summary  In an effort to determine the effects of bicarbonate (NaHCO3) ingestion on exercise performance, ten male college swimmers were studied during five different trials. Each trial consisted of five 91.4m (100-yd) front crawl swims with a two-minute rest interval between each bout. The trials consisted of two NaHCO3 treatments, two placebo trials and one test with no-drink. One hour before

Jiaping Gao; David L. Costill; Craig A. Horswill; Sung H. Park

1988-01-01

150

Sodium bicarbonate reduces postharvest decay development on melons  

Microsoft Academic Search

Sodium bicarbonate (SBC) inhibited in vitro mycelial growth of A. alternata, Fusarium spp. and R. stolonifer. SBC action was fungistatic rather than fungicidal. Coating commercially harvested ‘Galia’ and ‘Ein-Dor’ melons with wax containing 2% SBC reduced decay incidence after storage and shelf life simulation by four to seven-fold, to a commercially acceptable level of 6–7%, compared to untreated or waxed-treated

Y. Aharoni; E. Fallik; A. Copel; M. Gil; S. Grinberg; J. D. Klein

1997-01-01

151

Transplastomic integration of a cyanobacterial bicarbonate transporter into tobacco chloroplasts  

PubMed Central

Improving global yields of agricultural crops is a complex challenge with evidence indicating benefits in productivity are achieved by enhancing photosynthetic carbon assimilation. Towards improving rates of CO2 capture within leaf chloroplasts, this study shows the versatility of plastome transformation for expressing the Synechococcus PCC7002 BicA bicarbonate transporter within tobacco plastids. Fractionation of chloroplast membranes from transplastomic tobBicA lines showed that ~75% of the BicA localized to the thylakoid membranes and ~25% to the chloroplast envelope. BicA levels were highest in young emerging tobBicA leaves (0.12 ?mol m–2, ?7mg m–2) accounting for ~0.1% (w/w) of the leaf protein. In these leaves, the molar amount of BicA was 16-fold lower than the abundant thylakoid photosystem II D1 protein (~1.9 ?mol m–2) which was comparable to the 9:1 molar ratio of D1:BicA measured in air-grown Synechococcus PCC7002 cells. The BicA produced had no discernible effect on chloroplast ultrastructure, photosynthetic CO2-assimilation rates, carbon isotope discrimination, or growth of the tobBicA plants, implying that the bicarbonate transporter had little or no activity. These findings demonstrate the utility of plastome transformation for targeting bicarbonate transporter proteins into the chloroplast membranes without impeding growth or plastid ultrastructure. This study establishes the span of experimental measurements required to verify heterologous bicarbonate transporter function and location in chloroplasts and underscores the need for more detailed understanding of BicA structure and function to identify solutions for enabling its activation and operation in leaf chloroplasts.

Pengelly, J. J. L.; Forster, B.; von Caemmerer, S.; Badger, M. R.; Price, G. D.; Whitney, S. M.

2014-01-01

152

Comparison of zwitterionic N-alkylaminomethanesulfonic acids to related compounds in the Good buffer series  

PubMed Central

Summary Several N-alkyl and N,N-dialkylaminomethanesulfonic acids were synthesized (as zwitterions and/or sodium salts) to be tested for utility as biological buffers at lower pH levels than existing Good buffer compounds (aminoalkanesulfonates with a minimum of two carbons between amine and sulfonic acid groups as originally described by Norman Good, and in common use as biological buffers). Our hypothesis was that a shorter carbon chain (one carbon) between the amino and sulfonic acid groups should lower the ammonium ion pK a values. The alkylaminomethanesulfonate compounds were synthesized in aqueous solution by reaction of primary or secondary amines with formaldehyde/sodium hydrogensulfite addition compound. The pK a values of the ammonium ions of this series of compounds (compared to existing Good buffers) was found to correlate well with the length of the carbon chain between the amino and sulfonate moeties, with a significant decrease in amine basicity in the aminomethanesulfonate compounds (pK a decrease of 2 units or more compared to existing Good buffers). An exception was found for the 2-hydroxypiperazine series which shows only a small pK a decrease, probably due to the site of protonation in this compound (as confirmed by X-ray crystal structure). X-ray crystallographic structures of two members of the series are reported. Several of these compounds have pK a values that would indicate potential utility for buffering at pH levels below the normal physiological range (pK a values in the range of 3 to 6 without aqueous solubility problems) – a range that is problematic for currently available Good buffers. Unfortunately, the alkylaminomethanesulfonates were found to degrade (with loss of their buffering ability) at pH levels below the pK a value and were unstable at elevated temperature (as when autoclaving) – thus limiting their utility.

Hilliard, Newton P; Chhatre, Suneel A; Timofeeva, Tatiana V; Yakovenko, Andrey A; Dei, Daniel K; Mensah, Enoch A

2010-01-01

153

21 CFR 184.1138 - Ammonium chloride.  

Code of Federal Regulations, 2010 CFR

...12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The less soluble sodium salt separates out at elevated temperatures, and ammonium chloride is recovered from the filtrate on...

2009-04-01

154

21 CFR 184.1138 - Ammonium chloride.  

Code of Federal Regulations, 2010 CFR

...12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The less soluble sodium salt separates out at elevated temperatures, and ammonium chloride is recovered from the filtrate on...

2010-01-01

155

Electrochemical Studies on Silicate and Bicarbonate Ions for Corrosion Inhibitors  

NASA Astrophysics Data System (ADS)

Several types of carbon and high-strength low-alloy (HSLA) steels are being considered for use in the underground reinforcement of the Yucca Mountain Nuclear Waste Repository. In this study, potentiodynamic polarization under reducing conditions was used to determine the corrosion rates (CRs) and passivity behavior of AISI 4340 steel using different combinations of sodium silicate (Na2SiO3) and sodium bicarbonate (NaHCO3), in both pure water (PW) and simulated seawater (SW, 3.5 pct NaCl). These experiments were carried out to examine the potential inhibiting properties of the silicate or bicarbonate ions on the surface of the steel. The addition of sodium silicate to solution reduced the observed CR at room temperature to 19 ?m/y at 0.005 M concentration and 7 ?m/y at 0.025 M concentration in PW. The addition of sodium bicarbonate increased the CR from 84 ?m/y (C = 0.1 M) to 455 ?m/y (C = 1 M). These same behaviors were also observed at higher temperatures.

Mohorich, Michael E.; Lamb, Joshua; Chandra, Dhanesh; Daemen, Jaak; Rebak, Raul B.

2010-10-01

156

Supplemental Data in Support of Bicarbonate of Soda Stripping, Phase 1, Volume 2. Fresh Sodium Bicarbonate Paint-Stripping Media, Titration Graphs and Data.  

National Technical Information Service (NTIS)

The data in this supplemental document is to support the Bicarbonate of Soda Stripping - Phase I report. This data was used to calculate the titration endpoints for the fresh and spent sodium bicarbonate paint-stripping media. This information was used to...

J. E. Findley K. L. Gering L. A. Polson M. D. Argyle T. L. Harris

1992-01-01

157

Interaction of chloride and bicarbonate transport across the basolateral membrane of rabbit proximal straight tubule. Evidence for sodium coupled chloride/bicarbonate exchange.  

PubMed Central

The existence of chloride/bicarbonate exchange across the basolateral membrane and its physiologic significance were examined in rabbit proximal tubules. S2 segments of the proximal straight tubule were perfused in vitro and changes in intracellular pH (pHi) and chloride activity (aCli) were monitored by double-barreled microelectrodes. Total peritubular chloride replacement with gluconate increased pHi by 0.8, and this change was inhibited by a pretreatment with an anion transport inhibitor, SITS. Peritubular bicarbonate reduction increased aCli, and most of this increase was lost when ambient sodium was totally removed. The reduction rates of pHi induced by a peritubular bicarbonate reduction or sodium removal were attenuated by 20% by withdrawal of ambient chloride. SITS application to the bath in the control condition quickly increased pHi, but did not change aCli. However, the aCli slightly decreased in response to SITS when the basolateral bicarbonate efflux was increased by reducing peritubular bicarbonate concentration. It is concluded that sodium coupled chloride/bicarbonate exchange is present in parallel with sodium-bicarbonate cotransport in the basolateral membrane of the rabbit proximal tubule, and it contributes to the basolateral bicarbonate and chloride transport.

Sasaki, S; Yoshiyama, N

1988-01-01

158

21 CFR 184.1133 - Ammonium alginate.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Ammonium alginate. 184.1133 Section 184.1133 Food and...Substances Affirmed as GRAS § 184.1133 Ammonium alginate. (a) Ammonium alginate (CAS Reg. No. 9005-34-9) is the...

2010-01-01

159

Extraction of urea and ammonium ion  

NASA Technical Reports Server (NTRS)

Water purification system keeps urea and ammonium ion concentration below toxic limits in recirculated water of closed loop aquatic habitat. Urea is first converted to ammonium ions and carbon dioxide by enzygmatic action. Ammonium ions are removed by ion exchange. Bioburden is controlled by filtration through 0.45 micron millipore filters.

Anselmi, R. T.; Husted, R. R.; Schulz, J. R.

1977-01-01

160

An adaptive predictor for media playout buffering  

Microsoft Academic Search

Receiver playout buffers are required to smooth network delay variations for multimedia streams. Playout buffer algorithms such as those commonly used in the Internet, autoregressively measure the network delay and variation and adjust the buffer delay accordingly, to avoid packets arriving too late. In this work, we attempt to adjust the buffer delay based on a prediction of the network

Phillip Deleon; Cormac J. Sreenan

1999-01-01

161

Sodium Coupled Bicarbonate Influx Regulates Intracellular and Apical pH in Cultured Rat Caput Epididymal Epithelium  

PubMed Central

Background The epithelium lining the epididymis provides an optimal acidic fluid microenvironment in the epididymal tract that enable spermatozoa to complete the maturation process. The present study aims to investigate the functional role of Na+/HCO3? cotransporter in the pH regulation in rat epididymis. Method/Principal Findings Immunofluorescence staining of pan cytokeratin in the primary culture of rat caput epididymal epithelium showed that the system was a suitable model for investigating the function of epididymal epithelium. Intracellular and apical pH were measured using the fluorescent pH sensitive probe carboxy-seminaphthorhodafluor-4F acetoxymethyl ester (SNARF-4F) and sparklet pH electrode respectively to explore the functional role of rat epididymal epithelium. In the HEPES buffered Krebs-Henseleit(KH) solution, the intracellular pH (pHi) recovery from NH4Cl induced acidification in the cultured caput epididymal epithelium was completely inhibited by amiloride, the inhibitor of Na+/H+ exchanger (NHE). Immediately changing of the KH solution from HEPES buffered to HCO3? buffered would cause another pHi recovery. The pHi recovery in HCO3? buffered KH solution was inhibited by 4, 4diisothiocyanatostilbene-2, 2-disulfonic acid (DIDS), the inhibitor of HCO3? transporter or by removal of extracellular Na+. The extracellular pH measurement showed that the apical pH would increase when adding DIDS to the apical side of epididymal epithelial monolayer, however adding DIDS to the basolateral side had no effect on apical pH. Conclusions The present study shows that sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured caput epididymal epithelium.

Yang, Deng-Liang; Zhang, Geng; Chen, Si-Liang; Ruan, Ye-Chun; Ye, Ke-Nan; Cheng, Christopher H. K.; Zhou, Wen-Liang

2011-01-01

162

Phase diagram of ammonium nitrate  

NASA Astrophysics Data System (ADS)

Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.

Dunuwille, M.; Yoo, C. S.

2014-05-01

163

Determination of homologues of quaternary ammonium surfactants by capillary electrophoresis using indirect UV detection  

Microsoft Academic Search

This investigation describes the simultaneous separation of two major non-chromophoric quaternary ammonium surfactants, alkyltrimethyl- and dialkyldimethylammonium compounds (ATMACs and DADMACs, respectively), by capillary electrophoresis (CE) using indirect UV detection. The most effective separation conditions was 10mM phosphate buffer with 57.5% tetrahydrofuran and 3mM sodium dodecyl sulfate (SDS) at pH 4.3, and the sample hydrodynamic injection of up to 20s at

Hsueh-Ying Liu; Wang-Hsien Ding

2004-01-01

164

Ammonium Toxicity and Potassium Limitation in Yeast  

PubMed Central

DNA microarray analysis of gene expression in steady-state chemostat cultures limited for potassium revealed a surprising connection between potassium and ammonium: potassium limits growth only when ammonium is the nitrogen source. Under potassium limitation, ammonium appears to be toxic for Saccharomyces cerevisiae. This ammonium toxicity, which appears to occur by leakage of ammonium through potassium channels, is recapitulated under high-potassium conditions by over-expression of ammonium transporters. Although ammonium toxicity is well established in metazoans, it has never been reported for yeast. To characterize the response to ammonium toxicity, we examined the filtrates of these cultures for compounds whose excretion might serve to detoxify the ammonium (such as urea in mammals). Using liquid chromatography–tandem mass spectrometry to assay for a wide array of metabolites, we detected excreted amino acids. The amounts of amino acids excreted increased in relation to the severity of growth impairment by ammonium, suggesting that amino acid excretion is used by yeast for ammonium detoxification.

Hess, David C; Lu, Wenyun; Rabinowitz, Joshua D; Botstein, David

2006-01-01

165

Investigation of crystallization kinetics of sodium bicarbonate in a continuous stirred tank crystallizer  

NASA Astrophysics Data System (ADS)

In our previous work [J. Crystal Growth 263 (2004) 459], a supersaturation determination method using a high-precision densimeter was designed and developed for monitoring sodium bicarbonate supersaturation in the sodium carbonate-bicarbonate system, a two-component solution in equilibrium. In the present paper, we apply this method to the study of sodium bicarbonate continuous crystallization. It gives us access to the sodium bicarbonate supersaturation evolution. The sodium bicarbonate supersaturation evolution and their crystallization kinetics obtained in a continuous stirred tank crystallizer are investigated under different operational conditions, such as residence time, initial supersaturation and seeding. The induction time determined by density measurements is discussed. Mathematical modeling is used to interpret the supersaturation evolution. It is shown that measuring the density gives satisfying performances for studying the crystallization of a two-component solution in equilibrium, such as the sodium carbonate-bicarbonate system.

Zhu, Yi; Haut, Benoît; Halloin, Veronique; Delplancke-Ogletree, Marie-Paule

2005-08-01

166

Bicarbonate Ion as a Critical Factor in Photosynthetic Oxygen Evolution 1  

PubMed Central

Bicarbonate ion, not dissolved CO2 gas, is shown to increase 4- to 5-fold the rate of dichlorophenol indophenol reduction by isolated maize (Zea mays) chloroplasts. Glutaraldehyde fixed chloroplasts continue to exhibit bicarbonate-dependent 2,6-dichlorophenol indophenol reduction. Bicarbonate is shown to act close to the oxygen-evolving site, i.e. prior to the electron donation site of diphenyl carbazide to photosystem II. Dark incubation and light pretreatment of chloroplasts in various concentrations of bicarbonate, just prior to assay, indicate that bicarbonate binds to chloroplasts in the dark and is released again as the Hill reaction proceeds in the light. It is suggested that bicarbonate ions may play a critical role in the oxygen-evolving process in photosynthesis.

Stemler, Alan; Govindjee

1973-01-01

167

The effect of sodium bicarbonate and sodium citrate ingestion on anaerobic power during intermittent exercise  

Microsoft Academic Search

Summary  The effect of sodium bicarbonate and sodium citrate ingestion on cycling performance in three 30 s Wingate Anaerobic Tests\\u000a separated by 6 min recovery periods has been studied using 6 male subjects. Subjects ingested either sodium bicarbonate (B),\\u000a sodium bicarbonate plus sodium citrate (BC), sodium citrate (C) or sodium chloride (P) 2.5 h prior to exercise in a dose of

M. Parry-Billings; D. P. M. MacLaren

1986-01-01

168

Molecular Cloning of a New Sodium Bicarbonate Cotransporter cDNA from Human Retina  

Microsoft Academic Search

Sodium bicarbonate cotransport is an electrogenic process and a principal regulator of pH. A recently cloned sodium bicarbonate cotransporter (NBC1) is predominantly expressed in kidney. The presence of several isoforms is suggested from functional studies. We have cloned a new member of this family from human retina, which was named hNBC2 (for human sodium bicarbonate cotransporter 2). The hNBC2 has

Kenichi Ishibashi; Sei Sasaki; Fumiaki Marumo

1998-01-01

169

Anion?exchange membrane, water, and sodium bicarbonate extractions as soil tests for phosphorus  

Microsoft Academic Search

Three techniques were evaluated as soil P tests for western Canadian soils: anion?exchange membrane (AEM), water, and bicarbonate extraction. The AEM, water, and bicarbonate?extractable total P represented novel approaches to compare to the widely used bicarbonate?extractable inorganic P (traditional Olsen) soil test. In a range of Saskatchewan soils, similar trends in predicted relative P availability were observed for AEM, water

J. J. Schoenau; W. Z. Huang

1991-01-01

170

Hemodynamic Effects of Peritoneal Dialysis Solutions on the Rat Peritoneal Membrane: Role of Acidity, Buffer Choice, Glucose Concentration, and Glucose Degradation Products  

Microsoft Academic Search

Conventional peritoneal dialysis fluids (PDF) are unphysiologic because of their hypertonicity, high glucose and lactate concentrations, acidic pH, and presence of glucose degradation products (GDP). Long-term exposure to conven- tional PDF may cause functional and structural alterations of the peritoneal membrane. New PDF have a neutral pH, a low GDP content, and contain bicarbonate or lactate as the buffer. Intravital

SISKA MORTIER; S. DE VRIESE; JOHAN VAN DE VOORDE; THOMAS P. SCHAUB; JUTTA PASSLICK-DEETJEN; NORBERT H. LAMEIRE

2002-01-01

171

Regulation and roles of bicarbonate transporters in cancer  

PubMed Central

A unifying feature of solid tumors is a markedly altered pH profile compared to normal tissues. This reflects that solid tumors, despite completely different origins, often share several phenotypic properties with implications for intra- and extracellular pH. These include: a metabolic shift in most cancer cells toward more acid-producing pathways, reflecting both oncogenic signaling and the development of hypoxia in poorly perfused regions of the tumors; the poorly perfused and often highly dense tumor microenvironment, reducing the diffusive flux of acid equivalents compared to that in normal tissues; and the markedly altered regulation of the expression and activity of pH-regulatory transport proteins in cancer cells. While some of these properties of tumors have been well described in recent years, the great majority of the research in this clinically important area has focused on proton transport, in particular via the Na+/H+ exchanger 1 (SLC9A1, NHE1) and various H+ ATPases. We have, however, recently demonstrated that at least under some conditions, including in vitro models of HER2 positive breast cancer, and measurements obtained directly in freshly dissected human mammary carcinomas, bicarbonate transporters such as the electroneutral Na+, HCO?3 cotransporter (SLC4A7, NBCn1), are upregulated and play central roles in pH regulation. In this review, we summarize and discuss the current knowledge regarding the regulation and roles of bicarbonate transporters in cancer. Furthermore, we present new analyses of publicly available expression data demonstrating widely altered expression levels of SLC4- and SLC26 family transporters in breast-, lung-, and colon cancer patients, and we hypothesize that bicarbonate transporter dysregulation may have both diagnostic and therapeutic potential in cancer treatment.

Gorbatenko, Andrej; Olesen, Christina W.; Boedtkjer, Ebbe; Pedersen, Stine F.

2014-01-01

172

Effects of Oral Sodium Bicarbonate in Patients with CKD  

PubMed Central

Summary Background and objectives Metabolic acidosis contributes to muscle breakdown in patients with CKD, but whether its treatment improves functional outcomes is unknown. The choice of dose and tolerability of high doses remain unclear. In CKD patients with mild acidosis, this study evaluated the dose–response relationship of alkali with serum bicarbonate, its side effect profile, and its effect on muscle strength. Design, setting, participants, & measurements In this single-blinded pilot study from March of 2009 to August of 2010, 20 adults with estimated GFR 15–45 ml/min per 1.73 m2 and serum bicarbonate 20–24 mEq/L were treated during successive 2-week periods with placebo followed by escalating oral NaHCO3 doses (0.3, 0.6, and 1.0 mEq/kg per day). At each visit, handgrip strength and time required to complete 5 and 10 repetitions of a sit-to-stand test were measured. Results Each 0.1 mEq/kg per day increase in dose produced a 0.33 mEq/L (95% confidence interval=0.23–0.43 mEq/L) higher serum bicarbonate. Sit-to-stand time improved after 6 weeks of oral NaHCO3 (23.8±1.4 versus 22.2±1.6 seconds for 10 repetitions, P=0.002), and urinary nitrogen excretion decreased (?0.70 g/g creatinine [95% confidence interval=?1.11 to ?0.30] per 0.1 mEq/kg per day higher dose). No statistically significant change was seen in handgrip strength (29.5±9.6 versus 28.4±9.4 kg, P=0.12). Higher NaHCO3 doses were not associated with increased BP or greater edema. Conclusions NaHCO3 supplementation produces a dose-dependent increase in serum bicarbonate and improves lower extremity muscle strength after a short-term intervention in CKD patients with mild acidosis. Long-term studies are needed to determine if this finding translates into improved functional status.

Melamed, Michal L.; Bauer, Carolyn; Raff, Amanda C.; Hostetter, Thomas H.

2013-01-01

173

Possibility of safe processing of ammonium nitrate solutions with ammonium formate impurity  

SciTech Connect

Results are presented from research aimed at the development of a method for effective utilization of production wastes consisting of ammonium nitrate solutions with comparatively low concentrations, containing ammonium formate as an impurity. From these data it can be seen that with increasing content of ammonium formate, there is a trend toward a higher level of explosive properties of the ammonium nitrate and higher shock sensitivity. The experimental data also show that the ammonium nitrate samples obtained by preconcentrating the original solutions with the ammonium formate to 80-83% NH/sub 4/NO/sub 3/, followed by fluid-bed granulation, have the highest shock sensitivity.

Kil'man, Y.I.; Usachev, V.A.; Vakhrushev, Y.A.

1985-06-20

174

Equilibrium Studies of Sodium-Ammonium, Potassium-Ammonium, and Calcium-Ammonium Exchanges on Clinoptilolite Zeolite  

Microsoft Academic Search

Forward and reverse ion-exchange isotherms for the binary sodium-ammonium, potassium-ammonium, and calcium-ammonium systems on clinoptilolite have been measured in aqueous solutions at a total concentration of 0.1 equiv\\/dm and at 298 K. Prior to exchange experiments it was attempted to prepare homoionic forms of the zeolite by exhaustive treatments with appropriate salt solutions of cations. With no binary exchanges, full

M. A. Jama; H. Yuecel

1989-01-01

175

Buffered electrochemical polishing of niobium  

Microsoft Academic Search

The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a “damaged”\\u000a surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance\\u000a of the cavities is characterized by a sharp degradation of the quality factor at high surface magnetic field, a phenomenon\\u000a referred to as “Q-drop”. In

Gianluigi Ciovati; Hui Tian; Sean G. Corcoran

2011-01-01

176

Ammonium azide under hydrostatic compression  

NASA Astrophysics Data System (ADS)

The properties of ammonium azide NH4N3 upon compression were investigated using first-principles density functional theory. The equation of state was calculated and the mechanism of a phase transition experimentally observed at 3.3 GPa is elucidated. Novel polymorphs of NH4N3 were found using a simple structure search algorithm employing random atomic displacements upon static compression. The structures of three new polymorphs, labelled as B, C, and D, are similar to those of other metal azides.

Landerville, A. C.; Steele, B. A.; Oleynik, I. I.

2014-05-01

177

Neurogenic regulation of proximal bicarbonate and chloride reabsorption.  

PubMed

Although a change in renal nerve activity is known to alter proximal reabsorption, it is unclear whether reabsorption of NaHCO3 or NaCl or both are affected. Sprague-Dawley rats (n = 10) were studied using free-flow micropuncture techniques during euvolemia and following acute ipsilateral denervation. Glomerular filtration rate and single nephron glomerular filtration rate were stable. Absolute proximal bicarbonate reabsorption fell following denervation (933 +/- 40 to 817 +/- 30 pmol/min) with a parallel reduction in chloride reabsorption (1,643 +/- 116 to 1,341 +/- 129 peq/min). Urinary sodium, potassium, bicarbonate, and chloride excretion all increased significantly. To further assess the physiological significance of neurogenic modulation of proximal transport, other rats (n = 6) were subjected to acute unilateral nephrectomy (AUN). There is evidence that AUN induces a contralateral natriuresis (renorenal reflex) at least partially by causing inhibition of efferent renal nerve traffic. AUN caused significant changes in proximal NaHCO3 and NaCl reabsorption as well as in whole kidney electrolyte excretion in the same pattern as had denervation. Prior denervation of the remaining kidney prevented the proximal and whole kidney response to AUN (n = 6). In conclusion, depression of renal nerve activity inhibits both NaHCO3 and NaCl reabsorption in the rat superficial proximal convoluted tubule. The data are consistent with the hypothesis that changes in renal nerve activity modify whole kidney electrolyte excretion under physiological conditions at least partially by regulating proximal transport. PMID:3942224

Cogan, M G

1986-01-01

178

Ammonium Metabolism in the Green Hydra Symbiosis  

Microsoft Academic Search

Abstract. Inhibitors of enzymes,of ammonium,assimi- lation were used to test if assimilation of ammonium,in the green,hydra-Chlorella symbiosis,was,due,to host or symbionts. Both methionine sulphoximine (MSX, an in- hibitor of glutamine synthetase, found in both host and symbionts) and azaserine (AZS, an inhibitor of 2-oxoglu- tarate amido transferase, not found in the host) inhibited ammonium,uptake by the intact symbiosis. MSX was taken

P. J. Mcauley

1995-01-01

179

ANAEROBIC AMMONIUM OXIDATION IN THE MARINE ENVIRONMENT  

Microsoft Academic Search

Oceanographers noticed already many years ago that far less ammonium accumulated in anoxic fjords and basins, than would be\\u000a expected from the stoichiometry of heterotrophic denitrification. It was suggested that this ‘missing’ ammonium was oxidized\\u000a with nitrate to freeN2. Since then several otherworkers have argued based on chemical profiles that ammonium is oxidized anaerobically in oxygen\\u000a deficient marine sediments and

Marcel M. M. Kuypers; Gaute Lavik; Bo Thamdrup

180

Physiological aspects of ammonium and nitrate fertilization  

Microsoft Academic Search

Various physiological effects of ammonium, nitrate and mixed ammonium?nitrate nutrition of plants have been studied in this laboratory during the last years. Some of the characteristic distinctions observed between plants growing on these nitrogen sources are described and discussed. Biomass production of ammonium?grown plants increased with K concentration in the nutrient medium between 0.1 to 3 mM , while nitrate?fed

S. H. Lips; E. O. Leidi; M. Silberbush; M. I. M. Soares; O. E. M. Lewis

1990-01-01

181

Buffer Replacement Algorithms for Multimedia Storage Systems  

Microsoft Academic Search

In a disk-based storage system, a buffer cache is usedto reduce the number of disk I\\/O. The buffer manageris responsible for buffer replacement to free memoryin order to accommodate new data blocks from disk.An optimal buffer replacement algorithm is one whichyields the lowest number of cache misses and as a resultthe lowest number of disk I\\/O. In general, optimalbuffer replacement

Banu Özden; Rajeev Rastogi; Abraham Silberschatz

1996-01-01

182

Structural study of ammonium metatungstate  

SciTech Connect

Several techniques have been used to study the structure of the Keggin-type polyoxometalate salt ammonium metatungstate (AMT)-(NH{sub 4}){sub 6}[H{sub 2}W{sub 12}O{sub 40}]*nH{sub 2}O, a potential fuel cell catalyst. The dehydrated salt is comprised of a mixture of crystallites of different unit cells in a centered eutactic cubic configuration, with an average unit cell of a{approx_equal}12.295. Varied orientations of the Keggin ions in the cubic arrangement create the differences, and orientational variation within each unit cell size represents an energy well. Progressive hydration of each crystallite leads to expansion of the lattice, with the degree of expansion depending on the locations of the water added in relation to the Keggin ion, which is influenced by cation location and hydrogen bonding. The structural hypothesis is supported by electron diffraction of single and multicrystal samples, by powder density measurements, X-ray powder diffraction studies, synchrotron powder X-ray diffraction, and a priori structural modeling studies. Based on the structure, projected active site densities are compared with nanostructured platinum catalysts for fuel cell application. - Graphical abstract: The structure of ammonium metatungstate powders are highly dependent on hydration and POM molecule rotation, with cation and hydrogen bonding forces directing a mixture of structures that have been studied with bulk and single-crystal methods. The illustration shows Monte Carlo simulated anion structural disorder for the fully dehydrated form of the title compound.

Christian, Joel B. [OSRAM SYLVANIA Global Tungsten and Powders, Towanda, PA 18848 (United States); SUNY at Binghamton, Materials Science Program, Binghamton, NY 13902 (United States)], E-mail: joel.christian@sylvania.com; Whittingham, M. Stanley [SUNY at Binghamton, Materials Science Program, Binghamton, NY 13902 (United States)

2008-08-15

183

Capillary electrophoresis–electrospray ionization mass spectrometry using uncoated fused-silica capillaries and alkaline buffer solution for the analysis of small carboxylic acids  

Microsoft Academic Search

A simple and cost-effective capillary electrophoresis\\/mass spectrometric (CE\\/MS) method for the analysis of small carboxylic acids including succinate, malate, tartarate, maleinate and citrate, is described. All CE\\/MS experiments were performed with uncoated fused-silica capillaries and with alkaline volatile buffer solution (ammonium formate buffer, pH 10). Since sheath liquids have significant effects on the sensitivity in typical CE\\/MS applications, the effects

Hirokazu Sawada; Chika Nogami

2004-01-01

184

Sizing Buffers for Pipelined Forwarding Engine  

Microsoft Academic Search

Packet buffers in routers constitute a central element of packet networks. Selecting appropriate buffer size is an important and open research problem. This paper aims to size buffers for forwarding engine known as one of the main parts of a router. First, a high-speed pipeline which is designed for forwarding engine is presented, and its memory analysis model is also

Yufeng Li; Peng Yi; Han Qiu; Julong Lan

2006-01-01

185

Doped LZO buffer layers for laminated conductors  

DOEpatents

A laminated conductor includes a metallic substrate having a surface, a biaxially textured buffer layer supported by the surface of the substrate, the biaxially textured buffer layer comprising LZO and a dopant for mitigating metal diffusion through the LZO, and a biaxially textured conductor layer supported by the biaxially textured buffer layer.

Paranthaman, Mariappan Parans (Knoxville, TN) [Knoxville, TN; Schoop, Urs (Westborough, MA) [Westborough, MA; Goyal, Amit (Knoxville, TN) [Knoxville, TN; Thieme, Cornelis Leo Hans (Westborough, MA) [Westborough, MA; Verebelyi, Darren T. (Oxford, MA) [Oxford, MA; Rupich, Martin W. (Framingham, MA) [Framingham, MA

2010-03-23

186

Exploiting a buffer overflow using metasploit framework  

Microsoft Academic Search

Buffer overflow has been used for many years as an effective mean for system penetration to gain remote access [2, 3, 5, 6, 7]. Buffer overflow exploitation takes advantage of weak software programming such as boundary check for memory usage of declared buffers somewhere in the program to undermine software security and exploit its vulnerability so that attacker can remotely

Mustapha Refai

2006-01-01

187

Buffer Management for Wireless Media Streaming  

Microsoft Academic Search

We study playout buffer management at the receiver for supporting multimedia streaming services over unreliable wireless links. On one hand, memory is a precious resource on portable wireless devices and must be used judiciously. On the other hand, allocating a big playout buffer to a media streaming application reduces the probability of a playout in- terruption\\/freeze due to buffer underflow,

Aditya Dua; Nicholas Bambos

2007-01-01

188

Study of Buffer Size in Internet Routers.  

National Technical Information Service (NTIS)

In this report, we summarize the results of our small buffer project. The goals of the project were (1) to model the behavior of TCP in a network where the routers have very small buffers, (2) to determine a rule for sizing buffers in such networks, and (...

D. Towsley

2006-01-01

189

Functional characterization of NBC4: a new electrogenic sodium-bicarbonate cotransporter.  

PubMed

Sodium-bicarbonate cotransporters are homologous membrane proteins mediating the electrogenic or electroneutral transport of sodium and bicarbonate. Of the functionally characterized sodium-bicarbonate cotransporters (NBC), NBC1 proteins are known to be electrogenic. Here we report the cloning and functional characterization of NBC4c, a new splice variant of the NBC4 gene. At the amino acid level, NBC4c is 56% identical to NBC1 protein variants and 40% identical to electroneutral NBC3. When expressed in mammalian cells, NBC4c mediates electrogenic sodium-bicarbonate cotransport. The transport of sodium and bicarbonate is chloride independent and is completely inhibited by DIDS. NBC4c transcripts were detected in several tissues including brain, heart, kidney, testis, pancreas, muscle, and peripheral blood leukocytes. The data indicate that NBC4c is an electrogenic sodium-bicarbonate cotransporter. The finding that both NBC1 and NBC4c proteins function as electrogenic sodium-bicarbonate cotransporters will aid in determining the structural motifs responsible for this unique functional property, which distinguishes these transporters from other members of the bicarbonate transporter superfamily. PMID:11788353

Sassani, Pejvak; Pushkin, Alexander; Gross, Eitan; Gomer, Alla; Abuladze, Natalia; Dukkipati, Ramanath; Carpenito, Gerardo; Kurtz, Ira

2002-02-01

190

Failure of Adjunctive Bicarbonate to Improve Outcome in Severe Pediatric Diabetic Ketoacidosis  

Microsoft Academic Search

Study objective: Although adjunctive intravenous bicarbonate therapy is commonly recommended for children with severe diabetic ketoacidosis (DKA), no studies assessing clinical outcome with this therapy have ever been performed. Our objective was to determine whether bicarbonate therapy influenced outcome for pediatric DKA. Methods: The study was a retrospective consecutive case series of 147 admissions for severe DKA (initial pH ?7.15

Steven M Green; Steven G Rothrock; Jeffrey D Ho; Roger D Gallant; Rodney Borger; Tamara L Thomas; Grenith J Zimmerman

1998-01-01

191

SODIUM BENTONITE OR SODIUM BICARBONATE AS AIDS IN FEEDING HIGH-CONCENTRATE DIETS TO LAMBS 1  

Microsoft Academic Search

SUMMARY Studies were conducted to compare bento- nite and sodium bicarbonate as dietary aids in adaptation and subsequent performance of lambs fed high-concentrate diets under various conditions of protein supplementation. Three protein variations, including no supplemental protein (NSP), soybean meal (SBM) or urea, were factored with a control, 2% or 4% sodium bentonite, and 2% or 4% sodium bicarbonate in

G. B. Huntington; R. J. Emerick; L. B. Embry

2010-01-01

192

Electrogenic sodium/bicarbonate cotransport in rabbit renal cortical basolateral membrane vesicles.  

PubMed Central

The present studies examined the mechanism of bicarbonate transport across basolateral membrane vesicles prepared from rabbit renal cortex. Isotopic sodium uptake was stimulated by bicarbonate when compared with gluconate (2.5 nmol/mg protein per 5 s versus 1.4 nmol/mg protein per 5 s), and this process was inhibited by disulfonic stilbenes. Imposition of an interior-positive potassium diffusion potential further stimulated isotopic sodium uptake to 3.4 nmol/mg protein per 5 s, an effect that occurred only in the presence of bicarbonate and was blocked by disulfonic stilbenes. Kinetic analysis of the rate of bicarbonate-dependent sodium uptake as a function of sodium concentration revealed saturable stimulation with a Vmax of 2.7 nmol/mg protein per 2 s and a Km of 10.4 mM. The effect of bicarbonate concentration on bicarbonate-dependent sodium uptake was more complex. The present results demonstrate an electrogenic (negatively charged) sodium/bicarbonate cotransporter in basolateral membrane vesicles from the rabbit renal cortex. The electrogenicity implies a stoichiometry of at least two bicarbonate ions for each sodium ion.

Akiba, T; Alpern, R J; Eveloff, J; Calamina, J; Warnock, D G

1986-01-01

193

Effects of acetate and bicarbonate hemodialysis on cardiac function in chronic dialysis patients  

Microsoft Academic Search

Effects of acetate and bicarbonate hemodialysis on cardiac function in chronic dialysis patients. Previous studies have suggested that acetate hemodialysis causes myocardial depression. This study examines the acute effects of hemodialysis using, alternately, bicarbonate and acetate in the dialysate, on cardiac function in ten patients. These patients were also studied during acetate dialysis using a large surface area (SA) dialyzer.

B Rai Mehta; Diane Fischer; Masood Ahmad; Thomas D Dubose

1983-01-01

194

Decline of acid-sensitive plant species in heathland can be attributed to ammonium toxicity in combination with low pH.  

PubMed

The effects of increasing ammonium concentrations in combination with different pH levels were studied on five heathland plant species to determine whether their occurrence and decline could be attributed to ammonium toxicity and/or pH levels. Plants were grown in growth media amended with four different ammonium concentrations (10, 100, 500 and 1000 micromol l(-1)) and two pH levels resembling acidified (pH 3.5 or 4) and weakly buffered (pH 5 or 5.5) situations. Survival of Antennaria dioica and Succisa pratensis was reduced by low pH in combination with high ammonium concentrations. Biomass decreased with increased ammonium concentrations and decreasing pH levels. Internal pH of the plants decreased with increasing ammonium concentrations. Survival of Calluna vulgaris, Deschampsia flexuosa and Gentiana pneumonanthe was not affected by ammonium. Moreover, biomass increased with increasing ammonium concentrations. Biomass production of G. pneumonanthe reduced at low pH levels. A decline of acid-sensitive species in heathlands was attributed to ammonium toxicity effects in combination with a low pH. PMID:15819917

van den Berg, Leon J L; Dorland, Edu; Vergeer, Philippine; Hart, Miron A C; Bobbink, Roland; Roelofs, Jan G M

2005-05-01

195

Effect of lactate supplementation and sodium bicarbonate on 40-km cycling time trial performance.  

PubMed

The use of nutritional supplements to improve sporting performance and increase training adaptations is commonplace among athletes and is an expanding market in terms of product choice and availability. The purpose of this study was to examine the effects of 2 ergogenic aids with extracellular blood buffering potential, namely sodium bicarbonate (NaHCO3) and a lactate supplement, during a 40-km cycling time trial. Seven recreationally active men (age, 22.3 ± 3.3 years; height, 182.5 ± 6.5 cm; body mass, 79.2 ± 6.3 kg) completed five 40-km cycling time trials, including a familiarization trial in a randomized, blind, double placebo-controlled design. Subjects ingested (a) 300 mg·kg-1 body mass NaHCO3 (BICARB), (b) 45 mg·kg-1 body mass sodium chloride (PL-BICARB) as the placebo for the NaHCO3 trial, (c) 1115 mg lactate (LACTATE), or (d) plain flour as the placebo for the lactate trial (PL-LACTATE) 60 minutes before exercise. There was no significant difference in performance between the 4 conditions (p > 0.05). Although NaHCO3 ingestion induced significant changes in all the acid-base variables (all p < 0.05), no significant change was seen following lactate ingestion (p > 0.05). Subjects in the LACTATE condition did have a significantly higher heart rate (p < 0.05) without experiencing any greater perceived exertion (p > 0.05) than the other 3 conditions. Neither NaHCO3 nor lactate supplementation seem to improve 40-km cycling time trial performance. However, the potential benefits following LACTATE regarding perceived exertion require further research. PMID:23660571

Northgraves, Matthew J; Peart, Daniel J; Jordan, Christian A; Vince, Rebecca V

2014-01-01

196

Approach to the hemodialysis patient with an abnormal serum bicarbonate concentration.  

PubMed

We present a patient receiving hemodialysis with a persistently high serum bicarbonate concentration to illustrate the evaluation and management issues for patients with both high (>25mEq/L) and low (<20mEq/L) pretreatment values. Patients with high serum bicarbonate concentrations typically are malnourished and have low rates of endogenous acid production. Evaluation should begin with assessment of whether an acute and potentially reversible cause of metabolic alkalosis is present. If not, management should be directed at treating malnutrition. By contrast, patients with low predialysis serum bicarbonate concentrations, in the absence of an acute and reversible cause, may benefit from increasing the level by an adjustment in dialysate bicarbonate concentration. However, the level at which one should intervene and to what extent serum bicarbonate concentration should be increased are unresolved issues. Whether such an intervention will reduce mortality risk has not been determined. PMID:24731739

Lisawat, Panupong; Gennari, F John

2014-07-01

197

Influence of bicarbonate ions on the deterioration of mortar bars in sulfate solutions  

SciTech Connect

This work investigates the influence of bicarbonate ions on the deterioration of cementitious material exposed to sulfate ions. Mortars based on a CEM I and on a CEM III/B cement were investigated. Experimental investigations were compared to thermodynamic modeling and phase characterization to understand the differences in deterioration. The presence of bicarbonate ions significantly reduced the expansion of the CEM I mortars. Thermodynamic modeling showed that at high concentrations of bicarbonate ettringite and gypsum become unstable. Microstructural characterization combined with information from thermodynamic modeling suggests that conditions of high supersaturation with respect to ettringite are unlikely in the samples exposed in solutions containing bicarbonate. Consequently, expansive forces are not generated by the crystallization pressure of ettringite. There was little expansion of the CEM III/B sample even in the sodium sulfate solution. In the bicarbonate solution this mortar showed a highly leached zone at the surface in which calcite was observed.

Kunther, W., E-mail: Wolfgang.Kunther@empa.ch [Empa, Laboratory for Concrete and Construction Chemistry, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Lothenbach, B. [Empa, Laboratory for Concrete and Construction Chemistry, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland)] [Empa, Laboratory for Concrete and Construction Chemistry, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Scrivener, K. [EPFL, Laboratory of Construction Materials, CH-1015 Lausanne (Switzerland)] [EPFL, Laboratory of Construction Materials, CH-1015 Lausanne (Switzerland)

2013-02-15

198

EXCHANGE PROPERTIES OF AMMONIUM SALTS OF 12-HETEROPOLYACIDS. IV. Cs EXCHANGE ON AMMONIUM PHOSPHOTUNGSTATE AND PHOSPHOMOLYBDATE  

Microsoft Academic Search

Functional relations have been established describing cesium sorption on ; ammonium phosphotungstate (NHâPW) and ammonium phosphomolybdate (NHâ; PMo) as a function of the concentrations of nitric acid, ammonium nitrate, and ; cesium in the solution, and on the amount of sorbent. (auth);

J Krtil

1962-01-01

199

Biological Treatment of Ammonium-Rich Wastewater with the Partial Nitrification and Anaerobic Ammonium Oxidation  

Microsoft Academic Search

The aim of the investigation was to evaluate the nitrogen removal efficiency by using the combined partial nitrification and anaerobic ammonium oxidation (anammox) process for high-strength ammonium synthetic wastewater. The partial nitrification and anaerobic ammonium oxidation reactors were inoculate with domesticated sludge and operated respectively during the startup period. Subsequently, they were combined for stable operation when the partial nitrification

Qinglin Xie; Xiaoxia Li; Shaoyuan Bai; Yanhong Li

2010-01-01

200

Equilibrium studies of sodium-ammonium potassium-ammonium, and calcium-ammonium exchanges on clinoptilolite zeolite  

SciTech Connect

Forward and reverse ion-exchange isotherms for the binary sodium-ammonium, potassium-ammonium, and calcium-ammonium systems on clinoptilolite have been measured in aqueous solutions at a total concentration of 0.1 equiv/dm{sup 3} and at 298 K. Prior to exchange experiments it was attempted to prepare homoionic forms of the zeolite by exhaustive treatments with appropriate salt solutions of cations. With no binary exchanges, full replacement of the cation by the ammonium ion is observed, which conflicts with some earlier work on clinoptilolite. Despite the observed partial exchange levels, clinoptilolite shows a very high preference for ammonium ion over sodium and calcium but not over potassium. Thermodynamic values for the exchanges were calculated and compared with data in the literature. Both the selectivity and thermodynamic affinity sequence, in agreement with previous work reported in the literature, are K{sup +} > NH{sub 4}{sup +} > Na{sup +} > Ca{sup 2+}.

Jama, M.A.; Yuecel, H. (Middle East Technical Univ., Ankara (Turkey))

1989-12-01

201

On the influence of extracellular fluid volume expansion and of uremia on bicarbonate reabsorption in man.  

PubMed

The patterns of bicarbonate reabsorption during increasing plasma concentrations were studied in subjects with a range of glomerular filtration rates (GFR) from 170 to 2 ml/min. In a group of five subjects with GFR values above 30 ml/min, paired bicarbonate titration studies were performed first under conditions which minimized extracellular fluid (ECF) volume expansion, and second under conditions which were conducive to exaggerated expansion of ECF volume. In patients with GFR values below 30 ml/min, a single protocol was employed. Studies also were performed on two patients with far advanced renal disease who were nephrotic and exhibited a sodium-retaining state. When ECF volume expansion was minimized in the nonuremic subjects, values for bicarbonate reabsorption were well in excess of the usually accepted Tm level and over the range of plasma bicarbonate concentrations employed, no evidence of a Tm phenomenon was observed. A similar pattern emerged in the two nephrotic patients despite the presence of uremia. However, with both exaggerated expansion of ECF volume (GFR greater than 30) and in patients with advanced renal disease in the absence of exaggerated ECF volume expansion a tendency towards saturation kinetics for bicarbonate reabsorption was demonstrable. In comparing the minimized with the exaggerated expansion studies, evidence emerged for a decrease in both bicarbonate reabsorption per unit of GFR and the absolute rate of bicarbonate reabsorption. When ECF volume expansion was exaggerated in uremic patients after stable rates of bicarbonate reabsorption had been achieved, a decrease in reabsorption per unit of GFR and in absolute bicarbonate reabsorption occurred. The possible relationship of the factors controlling sodium excretion to the observed patterns of bicarbonate reabsorption is considered in the text. PMID:5441550

Slatopolsky, E; Hoffsten, P; Purkerson, M; Bricker, N S

1970-05-01

202

Interrelationships of chloride, bicarbonate, sodium, and hydrogen transport in the human ileum  

PubMed Central

Using a triple-lumen constant perfusion system, the following observations were made in normal subjects. First, chloride, bicarbonate, and sodium were found to exhibit net movement across ileal mucosa against electrochemical gradients. Second, during perfusion with a balanced electrolyte solution simulating plasma, the ileum generally absorbed, but sometimes secreted fluid. A reciprocal net movement of chloride and bicarbonate was noted when sodium movement was zero. Increasing rates of sodium absorption were associated with decreasing bicarbonate secretion rates and finally bicarbonate absorption. Even when bicarbonate was absorbed ileal contents were alkalinized (by contraction of luminal volume). Third, net chloride movement was found to be sensitive to bicarbonate concentration in ileal fluid. For instance, chloride was absorbed from solutions containing 14 or 44 mEq/liter of bicarbonate, but was secreted when ileal fluid contained 87 mEq/liter of bicarbonate. Fourth, when chloridefree (sulfate) solutions were infused, the ileum absorbed sodium bicarbonate and the ileal contents were acidified. Fifth, when plasma-like solutions were infused, the potential difference (PD) between skin and ileal lumen was near zero and did not change when chloride was replaced by sulfate in the perfusion solution. These results suggest that ileal electrolyte transport occurs via a simultaneous double exchange, Cl/HCO2 and Na/H. In this model neither the anion nor the cation exchange causes net ion movement; net movement results from the chemical reaction between hydrogen and bicarbonate. No other unitary model explains all of the following observations: (a) human ileal transport in vivo is essentially nonelectrogenic even though Na, Cl, and HCO3 are transported against electrochemical gradients, (b) the ileum can secrete as well as absorb, (c) ileal contents are alkalinized during absorption of or during secretion into a plasma-like solution, and (d) the ileum acidifies its contents when sulfate replaces chloride. Data obtained with a carbonic anhydrase inhibitor support the proposed model.

Turnberg, Leslie A.; Bieberdorf, Frederick A.; Morawski, Stephen G.; Fordtran, John S.

1970-01-01

203

Increased serum triglycerides and reduced HDL cholesterol in male rats after intake of ammonium chloride for 3 weeks  

PubMed Central

Background Previous data suggested that intake of sodas and other acid beverages might be associated with increased levels of serum triglycerides, lowered HDL cholesterol, and increased formation of mono unsaturated fatty acids, which are the preferred ones for triglyceride synthesis. The present work is an extension of these studies. Methods Thirty male rats were divided into 3 groups. All groups were given the same food, but various beverages: water (W), ammonium chloride, 200 mmol/L (AC), or sodium bicarbonate, 200 mmol/L (SB). Serum triglycerides, HDL cholesterol, and the fatty acid distribution in total serum lipids were determined. Delta9-desaturase in serum lipids was estimated by the ratio of palmitoleic to palmitic acid, and by the oleic/stearic acid ratio. Correlation and ANOVA were used to study associations and group differences. Results After 3 weeks, the AC group had higher triglyceride concentration and higher Delta9 desaturase indexes, but lower serum HDL and body weight as compared with the SB and W groups. In each of the groups, the oleic acid/stearic acid ratio correlated positively with serum triglycerides; in the pooled group the correlation coefficient was r?=?0.963, p<0.01. Conclusions Rats ingesting ammonium chloride as compared with sodium bicarbonate responded with increased desaturase indexes, increased serum triglycerides, and lowered HDL cholesterol concentration, thereby possibly contributing to explain the increased triglyceride concentration previously observed in subjects with a frequent intake of acid beverages, such as sodas containing carbonic acid, citric acid, and phosphoric acid.

2013-01-01

204

Improving Water Quality With Conservation Buffers  

NASA Astrophysics Data System (ADS)

Conservation buffer technologies are new approaches that need wider application. In-field buffer practices work best when used in combination with other buffer types and other conservation practices. Vegetative barriers may be used in combination with edge-of-field buffers to protect and improve their function and longevity by dispersing runoff and encouraging sediment deposition upslope of the buffer. It's important to understand how buffers can be managed to help reduce nutrient transport potential for high loading of nutrients from manure land application sites, A restored riparian wetland buffer retained or removed at least 59 percent of the nitrogen and 66 percent of the phosphorus that entered from an adjacent manure land application site. The Bear Creek National Restoration Demonstration Watershed project in Iowa has been the site of riparian forest buffers and filter strips creation; constructed wetlands to capture tile flow; stream-bank bioengineering; in-stream structures; and controlling livestock grazing. We need field studies that test various widths of buffers of different plant community compositions for their efficacy in trapping surface runoff, reducing nonpoint source pollutants in subsurface waters, and enhancing the aquatic ecosystem. Research is needed to evaluate the impact of different riparian grazing strategies on channel morphology, water quality, and the fate of livestock-associated pathogens and antibiotics. Integrating riparian buffers and other conservation buffers into these models is a key objective in future model development.

Lowrance, R.; Dabney, S.; Schultz, R.

2003-12-01

205

Phase diagram of ammonium nitrate.  

PubMed

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 N2, N2O, and H2O 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' transition above 17 GPa and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400°C. PMID:24320387

Dunuwille, Mihindra; Yoo, Choong-Shik

2013-12-01

206

Tri-benzyl-ammonium chloride.  

PubMed

Single crystals of the title salt, C21H21NH(+)·Cl(-), were isolated as a side product from the reaction involving [(C6H5CH2)3NH]2[HPO4] and Sn(CH3)3Cl in ethanol. Both the cation and the anion are situated on a threefold rotation axis. The central N atom in the cation has a slightly distorted tetra-hedral environment, with angles ranging from 107.7 to 111.16?(10)°. In the crystal, the tri-benzyl-ammonium cations and chloride anions are linked through N-H?Cl and C-H?Cl hydrogen bonds, leading to the formation of infinite chains along [001]. The crystal studied was a merohedral twin. PMID:24860409

Diallo, Waly; Diop, Libasse; Plasseraud, Laurent; Cattey, Hélène

2014-05-01

207

Tri-benzyl-ammonium chloride  

PubMed Central

Single crystals of the title salt, C21H21NH+·Cl?, were isolated as a side product from the reaction involving [(C6H5CH2)3NH]2[HPO4] and Sn(CH3)3Cl in ethanol. Both the cation and the anion are situated on a threefold rotation axis. The central N atom in the cation has a slightly distorted tetra­hedral environment, with angles ranging from 107.7 to 111.16?(10)°. In the crystal, the tri­benzyl­ammonium cations and chloride anions are linked through N—H?Cl and C—H?Cl hydrogen bonds, leading to the formation of infinite chains along [001]. The crystal studied was a merohedral twin.

Diallo, Waly; Diop, Libasse; Plasseraud, Laurent; Cattey, Helene

2014-01-01

208

Winter Wheat Fertilization: Post Ammonium Nitrate  

Microsoft Academic Search

Summary The potential for overwinter losses of nitrogen by denitrification and leaching have led to the recommendation that nitrogen fertilization of winter wheat be done using ammonium nitrate broadcast in the spring. However, spring broadcast application of urea can result in significant loss of nitrogen by volatilization and immobilization by surface residues. Since prilled ammonium nitrate is not available for

R. Byron Irvine; Guy Lafond; Randy Kutcher

209

Experimental acidification of two biogeochemically-distinct neotropical streams: buffering mechanisms and macroinvertebrate drift.  

PubMed

Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (~6) than streams that do not receive IGF (pH ~5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO(3)(-)) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 ?eq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 ?eq/L (40%). Protonation of HCO(3)(-) was an important buffering mechanism in both streams. Base cation, Fe(2+), and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 ?eq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 ?eq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and suggest that low-solute poorly buffered streams might be particularly vulnerable to episodic acidification. PMID:23201647

Ardón, Marcelo; Duff, John H; Ramírez, Alonso; Small, Gaston E; Jackman, Alan P; Triska, Frank J; Pringle, Catherine M

2013-01-15

210

Buffered Electrochemical Polishing of Niobium  

SciTech Connect

The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a 'damaged' surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance of the cavities is characterized by a sharp degradation of the quality factor when the surface magnetic field exceeds about 90 mT, a phenomenon referred to as 'Q-drop'. In cavities made of polycrystalline fine grain (ASTM 5) niobium, the Q-drop can be significantly reduced by a low-temperature ({approx} 120 C) 'in-situ' baking of the cavity if the chemical treatment was EP rather than BCP. As part of the effort to understand this phenomenon, we investigated the effect of introducing a polarization potential during buffered chemical polishing, creating a process which is between the standard BCP and EP. While preliminary results on the application of this process to Nb cavities have been previously reported, in this contribution we focus on the characterization of this novel electrochemical process by measuring polarization curves, etching rates, surface finish, electrochemical impedance and the effects of temperature and electrolyte composition. In particular, it is shown that the anodic potential of Nb during BCP reduces the etching rate and improves the surface finish.

Gianluigi Ciovati, Hui Tian, Sean Corcoran

2011-03-01

211

The origin of high sodium bicarbonate waters in the Atlantic and Gulf Coastal Plains  

USGS Publications Warehouse

Some sodium bicarbonate waters at depth in the Atlantic and Gulf Coastal Plains have the same bicarbonate content as the shallower calcium bicarbonate waters in the same formation and appear to be the result of replacement of calcium by sodium through the action of base-exchange minerals. Others, however, contain several hundred parts per million more of bicarbonate than any of the calcium bicarbonate waters and much more bicarbonate than can be attributed to solution of calcium carbonate through the action of carbon dioxide derived from the air and soil. As the waters in the Potomac group (Cretaceous) are all low in sulphate and as the environmental conditions under which the sediments of the Potomac group were deposited do not indicate that large amounts of sulphate are available for solution, it does not seem probable that carbon dioxide generated by chemical or biochemical breakdown of sulphate is responsible for the high sodium bicarbonate waters in this area. Sulphate as a source of oxygen is not necessary for the generation of carbon dioxide by carbonaceous material. Oxygen is an important constituent of carbonaceous material and carbon dioxide is a characteristic decomposition product of such material-as, for example, peat and lignite. Experimental work showed that distilled water, calcium bicarbonate water, and sodium bicarbonate water, after contact with lignite, calcium carbonate, and permutite (a base-exchange material), had all increased greatly in sodium bicarbonate content and had become similar in chemical character and in mineral content to high sodium bicarbonate waters found in the Coastal Plain. The tests indicated that carbonaceous material can act as a source of carbon dioxide, which, when dissolved in water, enables it to take into solution more calcium carbonate. If base-exchange materials are also present to replace calcium with sodium, a still greater amount of bicarbonate can be held in solution. The presence of carbonaceous material, together with calcium carbonate and base-exchange minerals in a formation is, therefore, sufficient to account for the occurrence in it of high sodium bicarbonate waters. ?? 1950.

Foster, M. D.

1950-01-01

212

21 CFR 582.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Aluminum ammonium sulfate. 582.1127 Section...General Purpose Food Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

2013-04-01

213

21 CFR 182.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Aluminum ammonium sulfate. 182.1127 Section...Purpose GRAS Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

2013-04-01

214

40 CFR 721.10582 - Quaternary ammonium compound (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Quaternary ammonium compound (generic). 721.10582 Section... § 721.10582 Quaternary ammonium compound (generic). (a) Chemical substance...identified generically as quaternary ammonium compound (PMN P-10-571) is subject...

2013-07-01

215

40 CFR 721.655 - Ethoxylated alkyl quaternary ammonium compound.  

Code of Federal Regulations, 2013 CFR

...Ethoxylated alkyl quaternary ammonium compound. 721.655 Section 721.655 ...Ethoxylated alkyl quaternary ammonium compound. (a) Chemical substance and significant...ethoxylated alkyl quaternary ammonium compound (PMN P-96-573) is subject...

2013-07-01

216

40 CFR 721.10302 - Zinc ammonium phosphate (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Zinc ammonium phosphate (generic). 721.10302 Section...Substances § 721.10302 Zinc ammonium phosphate (generic). (a) Chemical substance...identified generically as zinc ammonium phosphate (PMN P-00-442) is subject...

2013-07-01

217

21 CFR 184.1141a - Ammonium phosphate, monobasic.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Ammonium phosphate, monobasic. 184.1141a Section 184...Affirmed as GRAS § 184.1141a Ammonium phosphate, monobasic. (a) Ammonium phosphate, monobasic (NH4 H2 PO4 , CAS...

2013-04-01

218

40 CFR 721.10099 - Dialkyl dimethyl ammonium carbonate (generic).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Dialkyl dimethyl ammonium carbonate (generic). 721.10099...721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a...generically as dialkyl dimethyl ammonium carbonate (1:1) (PMN...

2010-07-01

219

40 CFR 721.10099 - Dialkyl dimethyl ammonium carbonate (generic).  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Dialkyl dimethyl ammonium carbonate (generic). 721.10099...721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a...generically as dialkyl dimethyl ammonium carbonate (1:1) (PMN...

2009-07-01

220

Ammonium Uptake by Micronesian Species of Gracilaria (Rhodophyta).  

National Technical Information Service (NTIS)

Research was carried out to examine the kinetics of ammonium uptake by thalli of several Gracilaria species from Micronesia to evaluate their relative potential for removing ammonium from mariculture systems. It was found that ammonium uptake was dependen...

S. G. Nelson R. N. Tsutsui

1981-01-01

221

Evidence for a Bicarbonate "Escort" Site in Haemophilus influenzae ?-Carbonic Anhydrase†, ‡  

PubMed Central

The Haemophilus influenzae ?-carbonic anhydrase (HICA) allosteric site variants V47A and G41A were overexpressed and purified to homogeneity. These variants have kcat/Km values similar to wild-type enzyme, and exhibit a similar dramatic decrease in catalytic activity at pH values below 8.0. However, both HICA-G41A and -V47A were serendipitously found to bind sulfate ion or bicarbonate ion near pairs of Glu50 and Arg64 residues located on the dimerization interface. In the case of HICA-V47A, bicarbonate ions simultaneously bind to both the dimerization interface and the allosteric sites. For HICA-G41A, 2 of 12 chains in the asymmetric unit bind bicarbonate ion exclusively at the dimerization interface, while the remaining 10 chains bind bicarbonate ion exclusively at the allosteric site. We propose that the new anion binding site along the dimerization interface of HICA is an “escort” site that represents an intermediate along the ingress/egress route of bicarbonate ion to/from the allosteric binding site. The structural evidence for sulfate binding at the “escort” site suggests that the mechanism of sulfate activation of HICA is the result of sulfate ion competing for bicarbonate at the “escort” site, preventing passage of bicarbonate from bulk solution to its allosteric site.

Rowlett, Roger S.; Hoffmann, Katherine M.; Failing, Hannah; Mysliwiec, Margaret M.; Samardzic, Dejan

2010-01-01

222

Bicarbonate secretion in the murine gallbladder--lessons for the treatment of cystic fibrosis.  

PubMed

The epithelium lining the gallbladder of mammalian species has absorptive and secretory functions. An important function is the secretion of a bicarbonate rich fluid that helps neutralise stomach acid and provides an appropriate environment for intestinal enzymes. In cystic fibrosis (CF) this secretory function is lost. This study concerns the bicarbonate secreting activity of murine gallbladders in vitro using wild type and CF mice and four main questions are considered as follows: a) Does the murine gallbladder secrete bicarbonate electrogenically and is this prevented in CF? b) Can the secretory activity in CF gallbladders be restored by gene therapy or pharmacologically? c) How is the cystic fibrosis transmembrane conductance regulator (CFTR) involved in bicarbonate secretion? d) Does the data offer prospects for the treatment of CF?. Work from both the author's laboratory and the literature will be reviewed. Consideration of the currently available data indicates that the wild type murine gallbladder does secrete bicarbonate electrogenically and that this is absent in CF mice. Further it has been demonstrated that bicarbonate secretory activity can be restored by both gene therapy and by the use of drugs. The role of CFTR in bicarbonate secretion remains equivocal. Much evidence suggests that CFTR can act as a channel for HCO(3)(-) ions as well as Cl(-) ions, while others propose a parallel arrangement of CFTR with a Cl(-)/HCO(3)(-) exchanger is necessary. The matter is further complicated by the regulatory role of CFTR on other transporting activities. Opportunities for possible application to man are discussed. PMID:11875268

Cuthbert, A W

2001-07-01

223

Sodium bicarbonate to prevent cardiac surgery-associated kidney injury: the end of a dream?  

PubMed Central

The rationale of urine alkalinization through intravenous sodium bicarbonate to prevent cardiac surgery-associated acute kidney injury relies on several pathophysiological arguments. Urine alkalinization is easily feasible in the ICU setting and is often considered to be associated with few side effects. In a previous issue of Critical Care, a retrospective study evaluates the effect of routine intravenous bicarbonate use to prevent cardiac surgery-associated acute kidney injury with cardiopulmonary bypass. This commentary discusses recent data on the use of bicarbonate to prevent cardiac surgery-associated acute kidney injury.

2012-01-01

224

Sodium bicarbonate to prevent cardiac surgery-associated kidney injury: the end of a dream?  

PubMed

ABSTRACT: The rationale of urine alkalinization through intravenous sodium bicarbonate to prevent cardiac surgery-associated acute kidney injury relies on several pathophysiological arguments. Urine alkalinization is easily feasible in the ICU setting and is often considered to be associated with few side effects. In a previous issue of Critical Care, a retrospective study evaluates the effect of routine intravenous bicarbonate use to prevent cardiac surgery-associated acute kidney injury with cardiopulmonary bypass. This commentary discusses recent data on the use of bicarbonate to prevent cardiac surgery-associated acute kidney injury. PMID:23234469

Hougardy, Jean-Michel; De Backer, Daniel

2012-12-12

225

Microbially mediated clinoptilolite regeneration in a multifunctional permeable reactive barrier used to remove ammonium from landfill leachate contamination: laboratory column evaluation.  

PubMed

This study focuses on multifunctional permeable reactive barrier (multibarrier) technology, combining microbial degradation and abiotic ion exchange processes for removal of ammonium from landfill leachate contamination. The sequential multibarrier concept relies on the use of a clinoptilolite-filled buffer compartment to ensure a robust ammonium removal in case of temporary insufficient microbial activities. An innovative strategy was developed to allow in situ clinoptilolite regeneration. Laboratory-scale clinoptilolite-filled columns were first saturated with ammonium, using real landfill leachate as well as synthetic leachates as feed media. Other inorganic metal cations, typically present in landfill leachate, had a detrimental influence on the ammonium removal capacity by competing for clinoptilolite exchange sites. On the other hand, the metals had a highly favorable impact on regeneration of the saturated material. Feeding the columns with leachate deprived from ammonium (e.g., by microbial nitrification in an upgradient compartment), resulted in a complete release of the previously sorbed ammonium from the clinoptilolite, due to exchange with metal cations present in the leachate. The released ammonium is then available for microbial consumption in a downgradient compartment. The regeneration process resulted in a slightly increased ammonium exchange capacity afterward. The described strategy throws a new light on sustainable use of sorption materials for in situ groundwater remediation, by avoiding the need for material replacement and the use of external chemical regenerants. PMID:20387879

Nooten, Thomas Van; Diels, Ludo; Bastiaens, Leen

2010-05-01

226

Unit 8: Buffers for Biochemical Reactions  

NSDL National Science Digital Library

The last of an eight-unit teaching and training module from Promega, this "introductory buffers laboratory is for use in undergraduate or highschool courses that cover basic topics in molecular biology or biochemistry" and includes "laboratories to illustrate basic chemistry concepts related to buffers and their functions." This unit is math-intensive, aimed at helping students feel comfortable performing laboratory calculations. It includes a lecture presentation ("Buffers for Biological Systems") and a students' and instructors' laboratory protocol.

2013-07-05

227

Optimization of buffer injection for the effective bioremediation of chlorinated solvents in aquifers  

NASA Astrophysics Data System (ADS)

Various techniques have been proposed to enhance biologically-mediated reductive dechlorination of chlorinated solvents in the subsurface, including the addition of fermentable organic substrate for the generation of H2 as an electron donor. One rate-limiting factor for enhanced dechlorination is the pore fluid pH. Organic acids and H+ ions accumulate in dechlorination zones, generating unfavorable conditions for microbial activity (pH < 6.5). The pH variation is a nonlinear function of the amount of reduced chlorinated solvents, and is affected by the organic material fermented, the chemical composition of the pore fluid and the soil's buffering capacity. Consequently, in some cases enhanced remediation schemes rely on buffer injection (e.g., bicarbonate) to alleviate this problem, particularly in the presence of solvent nonaqueous phase liquid (NAPL) source zones. However, the amount of buffer required - particularly in complex, evolving biogeochemical environments - is not well understood. To investigate this question, this work builds upon a geochemical numerical model (Robinson et al., Science of the Total Environment, submitted), which computes the amount of additional buffer required to maintain the pH at a level suitable for bacterial activity for batch systems. The batch model was coupled to a groundwater flow/solute transport/chemical reaction simulator to permit buffer optimization computations within the context of flowing systems exhibiting heterogeneous hydraulic, physical and chemical properties. A suite of simulations was conducted in which buffer optimization was examined within the bounds of the minimum concentration necessary to sustain a pH favorable to microbial activity and the maximum concentration to avoid excessively high pH values (also not suitable to bacterial activity) and mineral precipitation (e.g., calcite, which may lead to pore-clogging). These simulations include an examination of the sensitivity of this buffer concentration range to aquifer heterogeneity and groundwater velocity. This work is part of SABRE (Source Area BioREmediation), a collaborative international research project that aims to evaluate and improve enhanced bioremediation of chlorinated solvent source zones. In this context, numerical simulations are supporting the upscaling of the technique, including identifying the most appropriate buffer injection strategies for field applications

Brovelli, A.; Robinson, C.; Barry, A.; Kouznetsova, I.; Gerhard, J.

2008-12-01

228

Phase diagram of ammonium nitrate  

SciTech Connect

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.

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)] [Department of Chemistry and Institute for Shock Physics, Washington State University, Pullman, Washington 99164 (United States)

2013-12-07

229

All-optical buffering for DPSK packets  

NASA Astrophysics Data System (ADS)

Advanced modulation formats, such as DPSK, DQPSK, QAM, have become the mainstream technologies in the optical network over 40Gb/s, the DPSK format is the fundamental of all advanced modulation formats. Optical buffers, as a key element for temporarily storing packets in order to synchronization or contention resolution in optical nodes, must be adapted to this new requirement. Different from other current buffers to store the NRZ or RZ format, an all-optical buffer of storing DPSK packets based on nonlinear polarization rotation in SOA is proposed and demonstrated. In this buffer, a section of PMF is used as fiber delay line to maintain the polarization states unchanged, the driver current of SOA is optimized, and no amplifier is required in the fiber loop. A packet delay resolution of 400ns is obtained and storage for tens rounds is demonstrated without significant signal degradation. Using proposed the new tunable DPSK demodulator, bit error rate has been measured after buffering for tens rounds for 10Gb/s data payload. Configurations for First-in First-out (FIFO) buffer or First-in Last-out (FILO) buffer are proposed based on this buffer. The buffer is easy control and suitable for integration. The terminal contention caused by different clients can be mitigated by managing packets delays in future all-optical network, such as optical packet switching network and WDM switching network.

Liu, Guodong; Wu, Chongqing; Liu, Lanlan; Wang, Fu; Mao, Yaya; Sun, Zhenchao

2013-12-01

230

Substrate specificity of Rhbg: ammonium and methyl ammonium transport  

PubMed Central

Rhbg is a nonerythroid membrane glycoprotein belonging to the Rh antigen family. In the kidney, Rhbg is expressed at the basolateral membrane of intercalated cells of the distal nephron and is involved in NH4+ transport. We investigated the substrate specificity of Rhbg by comparing transport of NH3/NH4+ with that of methyl amine (hydrochloride) (MA/MA+), often used to replace NH3/NH4+, in oocytes expressing Rhbg. Methyl amine (HCl) in solution exists as neutral methyl amine (MA) in equilibrium with the protonated methyl ammonium (MA+). To assess transport, we used ion-selective microelectrodes and voltage-clamp experiments to measure NH3/NH4+- and MA/MA+-induced intracellular pH (pHi) changes and whole cell currents. Our data showed that in Rhbg oocytes, NH3/NH4+ caused an inward current and decrease in pHi consistent with electrogenic NH4+ transport. These changes were significantly larger than in H2O-injected oocytes. The NH3/NH4+-induced current was not inhibited in the presence of barium or in the absence of Na+. In Rhbg oocytes, MA/MA+ caused an inward current but an increase (rather than a decrease) in pHi. MA/MA+ did not cause any changes in H2O-injected oocytes. The MA/MA+-induced current and pHi increase were saturated at higher concentrations of MA/MA+. Amiloride inhibited MA/MA+-induced current and the increase in pHi in oocytes expressing Rhbg but had no effect on control oocytes. These results indicate that MA/MA+ is transported by Rhbg but differently than NH3/NH4+. The protonated MA+ is likely a direct substrate whose transport resembles that of NH4+. Transport of electroneutral MA is also enhanced by expression of Rhbg.

Abdulnour-Nakhoul, Solange M.; Boulpaep, Emile L.; Rabon, Edd; Schmidt, Eric; Hamm, L. Lee

2010-01-01

231

RETRACTED: Response to Comment on "Intravenous Sodium Bicarbonate Therapy in Severely Acidotic Diabetic Ketoacidosis".  

PubMed

Duhon B, Attridge RL, Hughes DW. Response to comment on "Intravenous Sodium Bicarbonate Therapy in Severely Acidotic Diabetic Ketoacidosis" [published online December 5, 2013]. Ann Pharmacother. doi:10.1177/1060028013513885. PMID:24311726

2014-06-01

232

Bicarbonate-Induced Iron Complexes and Iron Absorption: One Effect of Pancreatic Secretions.  

National Technical Information Service (NTIS)

The addition of sodium bicarbonate to iron solutions produces both soluble macromolecular iron chelates and iron precipitates and causes decreased absorption of test doses of iron by normal guinea pigs. Similar physicochemical changes occur when iron solu...

B. I. Benjamin S. Cortell M. E. Conrad

1967-01-01

233

The Structure and Spectroscopy of Cyanate and Bicarbonate Ions. Astrophysical Implications  

NASA Astrophysics Data System (ADS)

Cyanate and bicarbonate are two ions that play active roles in many fields of physics and chemistry, including biological sciences and astrochemistry. We present here a comprehensive study of these species covering a range of phases and methodologies. We have performed theoretical calculations on the isolated ions and their hydrates with one to four water molecules, and in clusters with 15 water molecules. The predicted infrared spectra are compared with observed spectra from experiments where liquid droplets of their solutions are frozen at 14 K on a substrate, to mimic some astrophysical conditions. Crystals of cyanate and bicarbonate sodium and potassium salts are also studied experimental and theoretically. As well, the spontaneous decomposition of cyanate into bicarbonate is documented from the spectra of an aged solution. Finally, the possible astrophysical observation of bicarbonate in water-containing particles is discussed.

Moreno, M. A.; Maté, B.; Rodríguez-Lazcano, Y.; Gálvez, O.; Gómez, P. C.; Herrero, V. J.; Escribano, R.

2013-10-01

234

Thermal Analysis Studies of Ammonium Uranyl Carbonate.  

National Technical Information Service (NTIS)

The simultaneous thermogravimetry and differential thermal analysis of the ammonium uranyl carbonate powder were performed with heat balance in the following atmosphers: Air, Ar and Ar-8%H/sub 2/. The thermogravimetry and differential thermal analysis cur...

X. Cao X. Ma F. Wang N. Liu C. Ji

1988-01-01

235

21 CFR 184.1133 - Ammonium alginate.  

Code of Federal Regulations, 2010 CFR

...CAS Reg. No. 9005-34-9) is the ammonium salt of alginic acid, a natural polyuronide constituent of certain brown...alginate is prepared by the neutralization of purified alginic acid with appropriate pH control agents....

2009-04-01

236

Decomposition of Four Ammonium Nitrate Propellants.  

National Technical Information Service (NTIS)

The biodegradability of four ammonium nitrate propellants, trimethylammonium nitrate (TMAN), isopropylammonium nitrate (IPAN), triethanolammonium nitrate (TEAN), and hydroxylammonium nitrate (HAN) was assessed in batch and continuous cultures under a vari...

D. L. Kaplan D. J. Emerson P. A. Riley A. M. Kaplan

1983-01-01

237

A sodium bicarbonate transporter from sea urchin spermatozoa.  

PubMed

Bicarbonate (HCO3-) transporters play crucial roles in cell-signaling pathways and are essential for cell viability. Here we describe the first cloning and localization of a HCO3- transporter from sperm of the sea urchin, Strongylocentrotus purpuratus. The deduced protein is 1214 amino acids and has a calculated molecular mass of 135 kDa. The annotated protein coding region of the transporter gene consists of 24 exons. The most similar human protein is the Na+/HCO3- cotransporter-2 (NBC2), which has 53% identity and 68% similarity to the sea urchin protein. The sea urchin protein shares the major structural features of HCO3- transporters, including 13 transmembrane segments, a DIDS (4,4-diiodothiocyanatostilbene-2, 2-disulfonic acid) binding motif and N-linked glycosylation sites. It has longer N- and C-terminal cytoplasmic domains compared to human HCO3- transporters. The sea urchin protein possesses a relatively long 3rd extracellular loop with four conserved cysteine residues. This is characteristic for Na+/HCO3- cotransporters, but not for anion exchangers, suggesting that the sea urchin protein is a Na+/HCO3- cotransporter. It is therefore designated as Sp-NBC. A neighbor-joining tree shows that Sp-NBC branches closer to the electroneutral type of HCO3- transporters. Western immunoblots and immunoflourescence show that Sp-NBC is concentrated in the flagellar plasma membrane, suggesting a role in motility regulation. PMID:16603323

Gunaratne, Herath Jayantha; Nomura, Mamoru; Moy, Gary W; Vacquier, Victor D

2006-06-21

238

Impaired pancreatic ductal bicarbonate secretion in cystic fibrosis.  

PubMed

Patients with cystic fibrosis demonstrate a defect in HCO(3)(-) secretion by their pancreatic duct cells. However, attempts toward understanding or correcting this defect have been hampered by a lack of knowledge regarding the cellular and molecular mechanisms mediating HCO(3)(-) transport in these cells. Recent functional and molecular studies indicate a major role for a basolateral electrogenically-driven Na(+):HCO(3)(-) cotransporter (NBC1) in mediating the transport of HCO(3)(-) into the duct cells. The HCO(3)(-) exits at the lumen predominantly via two recently discovered apical HCO(3)(-) transporters. cAMP, which mediates the stimulatory effect of secretin on pancreatic ductal HCO(3)(-) secretion, potentiates the basolateral Na(+):HCO(3)(-) cotransporter due to generation of a favorable electrogenic gradient as a result of membrane depolarization by Cl(-)-secreting cystic fibrosis transmembrane conductance regulator (CFTR). Two apical HCO(3)(-) transporters drive the secretion of bicarbonate into the pancreatic duct lumen. Molecular and functional studies indicate that CFTR upregulates the expression of these two apical HCO(3)(-) transporters. In addition, CFTR may also upregulate the expression of certain water channels and facilitate the secretion of fluid into the duct lumen. In brief, current research suggests that the defect in pancreatic HCO(3)(-) secretion in patients with cystic fibrosis is multifactorial and involves the alteration in the function/expression of transporters at the basolateral and luminal membrane domains of the duct cells. PMID:11875265

Soleimani, M

2001-07-01

239

Bicarbonate of soda paint stripping process validation and material characterization  

NASA Technical Reports Server (NTRS)

The Aircraft Production Division at San Antonio Air Logistics Center has conducted extensive investigation into the replacement of hazardous chemicals in aircraft component cleaning, degreasing, and depainting. One of the most viable solutions is process substitution utilizing abrasive techniques. SA-ALC has incorporated the use of Bicarbonate of Soda Blasting as one such substitution. Previous utilization of methylene chloride based chemical strippers and carbon removal agents has been replaced by a walk-in blast booth in which we remove carbon from engine nozzles and various gas turbine engine parts, depaint cowlings, and perform various other functions on a variety of parts. Prior to implementation of this new process, validation of the process was performed, and materials and waste stream characterization studies were conducted. These characterization studies examined the effects of the blasting process on the integrity of the thin-skinned aluminum substrates, the effects of the process on both air emissions and effluent disposal, and the effects on the personnel exposed to the process.

Haas, Michael N.

1995-01-01

240

Ammonium and urea removal by Spirulina platensis  

Microsoft Academic Search

Different concentrations either of ammonium chloride or urea were used in batch and fed-batch cultivations of Spirulina platensis to evaluate the possibility of substituting nitrate by cheaper reduced nitrogen sources in wastewaters biotreatment. The\\u000a maximum nitrogen concentration able to sustain the batch growth of this microalga without inhibition was 1.7 mM in both cases.\\u000a Ammonium chloride was limiting for the growth

A. Converti; S. Scapazzoni; A. Lodi; J. C. M. Carvalho

2006-01-01

241

Efficient degradation of organic pollutants in aqueous solution with bicarbonate-activated hydrogen peroxide  

Microsoft Academic Search

Bicarbonate anion is an efficient activator for hydrogen peroxide to generate many active oxygen species including peroxymonocarbonate (HCO4-), superoxide ion (O2-) and singlet oxygen (1O2). This study aims to understand the oxidative degradation of organic pollutants including methyl blue, methyl orange, rhodamine B, and 4-chlorophenol, with H2O2 activated by sodium bicarbonate at room temperature. The obtained results indicate that such

Aihua Xu; Xiaoxia Li; Hui Xiong; Guochuan Yin

2011-01-01

242

Haemodynamic consequences of changing bicarbonate and calcium concentrations in haemodialysis fluids  

PubMed Central

Background. In a previous study we demonstrated that mild metabolic alkalosis resulting from standard bicarbonate haemodialysis induces hypotension. In this study, we have further investigated the changes in systemic haemodynamics induced by bicarbonate and calcium, using non-invasive procedures. Methods. In a randomized controlled trial with a single-blind, crossover design, we sequentially changed the dialysate bicarbonate and calcium concentrations (between 26 and 35?mmol/l for bicarbonate and either 1.25 or 1.50?mmol/l for calcium). Twenty-one patients were enrolled for a total of 756 dialysis sessions. Systemic haemodynamics was evaluated using pulse wave analysers. Bioimpedance and BNP were used to compare the fluid status pattern. Results. The haemodynamic parameters and the pre-dialysis BNP using either a high calcium or bicarbonate concentration were as follows: systolic blood pressure (+5.6 and ?4.7?mmHg; P < 0.05 for both), stroke volume (+12.3 and +5.2?ml; P < 0.05 and ns), peripheral resistances (?190 and ?171 dyne s cm?5; P < 0.05 for both), central augmentation index (+1.1% and ?2.9%; ns and P < 0.05) and BNP (?5 and ?170?ng/l; ns and P < 0.05). The need of staff intervention was similar in all modalities. Conclusions. Both high bicarbonate and calcium concentrations in the dialysate improve the haemodynamic pattern during dialysis. Bicarbonate reduces arterial stiffness and ameliorates the heart tolerance for volume overload in the interdialytic phase, whereas calcium directly increases stroke volume. The slight hypotensive effect of alkalaemia should motivate a probative reduction of bicarbonate concentration in dialysis fluid for haemodynamic reasons, only in the event of failure of classical tools to prevent intradialytic hypotension.

Gabutti, Luca; Bianchi, Giorgia; Soldini, Davide; Marone, Claudio; Burnier, Michel

2009-01-01

243

Rheogenic sodium-bicarbonate cotransport in the peritubular cell membrane of rat renal proximal tubule  

Microsoft Academic Search

The mechanism of bicarbonate transport across the peritubular cell membrane was investigated in rat kidney proximal tubules in situ by measuring cell pH and cell Na+ activity in response to sudden reduction of peritubular Na+ and\\/or HCO3-. The following observations were made: 1. sudden peritubular reduction of either ion concentration produced the same transient depolarizing potential response; 2. bicarbonate efflux

K. Yoshitomi; B.-Ch. Burckhardt; E. Frömter

1985-01-01

244

Effect of Sodium Bicarbonate Administration on Mortality in Patients with Lactic Acidosis: A Retrospective Analysis  

PubMed Central

Background Lactic acidosis is a common cause of high anion gap metabolic acidosis. Sodium bicarbonate may be considered for an arterial pH <7.15 but paradoxically depresses cardiac performance and exacerbates acidosis by enhancing lactate production. This study aimed to evaluate the cause and mortality rate of lactic acidosis and to investigate the effect of factors, including sodium bicarbonate use, on death. Methods We conducted a single center analysis from May 2011 through April 2012. We retrospectively analyzed 103 patients with lactic acidosis among 207 patients with metabolic acidosis. We used SOFA and APACHE II as severity scores to estimate illness severity. Multivariate logistic regression analysis and Cox regression analysis models were used to identify factors that affect mortality. Results Of the 103 patients with a mean age of 66.1±11.4 years, eighty-three patients (80.6%) died from sepsis (61.4%), hepatic failure, cardiogenic shock and other causes. The percentage of sodium bicarbonate administration (p?=?0.006), catecholamine use, ventilator care and male gender were higher in the non-survival group than the survival group. The non-survival group had significantly higher initial and follow-up lactic acid levels, lower initial albumin, higher SOFA scores and APACHE II scores than the survival group. The mortality rate was significantly higher in patients who received sodium bicarbonate. Sodium bicarbonate administration (p?=?0.016) was associated with higher mortality. Independent factors that affected mortality were SOFA score (Exp (B)?=?1.72, 95% CI?=?1.12–2.63, p?=?0.013) and sodium bicarbonate administration (Exp (B)?=?6.27, 95% CI?=?1.10–35.78, p?=?0.039). Conclusions Lactic acidosis, which has a high mortality rate, should be evaluated in patients with metabolic acidosis. In addition, sodium bicarbonate should be prescribed with caution in the case of lactic acidosis because sodium bicarbonate administration may affect mortality.

Kim, Hyun Jeong; Son, Young Ki; An, Won Suk

2013-01-01

245

Urease-independent chemotactic responses of Helicobacter pylori to urea, urease inhibitors, and sodium bicarbonate.  

PubMed Central

Helicobacter pylori CPY3401 and an isogenic urease-negative mutant, HPT73, showed chemotactic responses to urea, flurofamide (a potent urease inhibitor), and sodium bicarbonate. Since urea and sodium bicarbonate are secreted through the gastric epithelial surface and hydrolysis of urea by urease on the bacterial surface is essential for colonization, the chemotactic response of H. pylori may be crucial for its colonization and persistence in the stomach.

Mizote, T; Yoshiyama, H; Nakazawa, T

1997-01-01

246

Comparison of three buffers used in the formulation of buffered charcoal yeast extract medium.  

PubMed

Growth of Legionella spp. on buffered charcoal yeast extract medium supplemented with alpha-ketoglutarate and formulated with 3-(n-morpholino)propanesulfonic acid (MOPS), 3-(n-morpholino)-2-hydroxypropanesulfonic acid (MOPSO), or n-(2-acetamido)-2-aminoethanesulfonic acid (ACES) buffer was similar. With three exceptions, growth was no different in buffered yeast extract broth supplemented with alpha-ketoglutarate and formulated with MOPS or ACES buffer. PMID:8308131

Edelstein, P H; Edelstein, M A

1993-12-01

247

Bicarbonate-induced activation of taurocholate transport across the basal plasma membrane of human term trophoblast.  

PubMed

The efflux of [14C]taurocholate from previously loaded vesicles, obtained from basal plasma membrane of human trophoblast, was studied. Apparent Km (620 microM) and Vmax (1.79 nmol.min-1.mg protein-1) values were similar to those found in influx experiments (Marin et al., Gastroenterology 99: 1431-1438, 1990). Transmembrane gradients of both bicarbonate (100 mM) and unlabeled taurocholate (0.5 mM) accelerated [14C]taurocholate efflux. The bicarbonate-induced effect was not abolished by carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and K(+)-valinomycin voltage clamp. Neither was it mimicked by 5,5'-dimethyloxazolidine 2,4-dione (DMO) or by other organic (taurine, glycine, lactate, or acetate) or inorganic (Cl-, SCN-, HPO24-, or SO24-) anions, and it was not sensitive to carbonic anhydrase inhibitors. No effect of bicarbonate was observed either in the absence of gradient or in the presence of a cis-directed gradient. Bicarbonate-induced transstimulation was related to an increase in the value for the apparent Vmax (+30%). Study of the stoichiometry suggests that the most probable coupling ratio is one, bicarbonate: taurocholate. In summary, these results provide evidence for the existence of a bicarbonate-driven anion exchange in the basal plasma membrane of the human term placental trophoblast. PMID:2058676

el-Mir, M Y; Eleno, N; Serrano, M A; Bravo, P; Marin, J J

1991-06-01

248

Intestinal transport of water, sodium & glucose from an electrolyte solution with & without bicarbonate.  

PubMed

In this study we have evaluated the role of bicarbonate on water and sodium transport in normal and secreting ilea of rabbits as controversy exists regarding the inclusion of bicarbonate in oral rehydration solution (ORS). In anaesthetized rabbits 10 cm closed ileal loops were constructed and filled with 5 ml of an electrolyte solution with and without bicarbonate, which contained polyethylene glycol (PEG; mol wt 4,000) as a non-absorbable marker. The fluid was withdrawn after an hour and analyzed for PEG, sodium and glucose. Similar studies were carried out in loops one hour after exposure to 1 microgram/ml of purified cholera toxin. Body temperature was maintained at 37 degrees C during the experiment by using a lamp. The mean +/- SE of water and sodium absorption, with bicarbonate versus without bicarbonate, was -1.4 +/- 0.1 vs -1.1 +/- 0.3 ml/h/10 cm, and -340.8 +/- 23.0 vs -308.4 +/- 35.6 mM/h/10 cm, respectively from secreting rabbit ilea. A similar effect was observed in normal ilea. It is concluded that bicarbonate containing electrolyte solution has no additional promoting effect on water and sodium absorption in normal or secreting ilea of rabbits. PMID:8952178

Islam, S; Mahalanabis, D; Chowdhury, A K; Sarker Abdul Wahed, S A; Rahman, A S

1996-10-01

249

Resilience to suicidality: The buffering hypothesis  

Microsoft Academic Search

Recent years have seen a growing interest into resilience to suicidality, which has been described as a perception or set of beliefs which buffer individuals from suicidality in the face of stressors. The current review extends this research by introducing the buffering hypothesis, a framework for the investigation of resilience to suicidality. The key proposal of this is that psychological

Judith Johnson; Alex M. Wood; Patricia Gooding; Peter J. Taylor; Nicholas Tarrier

2011-01-01

250

Shaking table testing of geofoam seismic buffers  

Microsoft Academic Search

The paper describes the experimental design and results of tests used to investigate the use of compressible EPS (geofoam) seismic buffers to attenuate dynamic loads against rigid retaining wall structures. The tests were carried out using 1-m-high models mounted on a large shaking table. Three different geofoam buffer materials retaining a sand soil were tested under idealized dynamic loading conditions.

Richard J. Bathurst; Saman Zarnani; Andrew Gaskin

2007-01-01

251

Modeling buffer layer IGBTs for circuit simulation  

Microsoft Academic Search

The dynamic behavior of commercially available buffer layer IGBTs is described. It is shown that buffer layer IGBTs become much faster at high voltages than nonbuffer layer IGBTs with similar low voltage characteristics. Because the fall times specified in manufacturers' data sheets do not reflect the voltage dependence of switching speed, a new method of selecting devices for different circuit

1995-01-01

252

Database buffer paging in virtual storage systems  

Microsoft Academic Search

Three models, corresponding to different sets of assumptions, are analyzed to study the behavior of a database buffer in a paging environment. The models correspond to practical situations and vary in their search strategies and replacement algorithms. The variation of I\\/O cost with respect to buffer size is determined for the three models. The analysis is valid for arbitrary database

Tomás Lang; Christopher Wood; Eduardo B. Fernández

1977-01-01

253

UNDERSTANDING, DERIVING, AND COMPUTING BUFFER CAPACITY  

EPA Science Inventory

Derivation and systematic calculation of buffer capacity is a topic that seems often to be neglected in chemistry courses and given minimal treatment in most texts. However, buffer capacity is very important in the chemistry of natural waters and potable water. It affects corro...

254

Buffer Management for Video Database Systems  

Microsoft Academic Search

Future multimedia information systems are likely to manage thousands of videos with various lengths and display requirements. Mismatch of playback and delivery rates of compressed video data requires sophisticated buffer management algorithms to guarantee smooth playback of video data. In this paper, we address some of the many design and operational issues including buffer size requirements, refreshing policies, and support

Doron Rotem; J. Leon Zhao

1995-01-01

255

The buffer capacity of airway epithelial secretions  

PubMed Central

The pH of airway epithelial secretions influences bacterial killing and mucus properties and is reduced by acidic pollutants, gastric reflux, and respiratory diseases such as cystic fibrosis (CF). The effect of acute acid loads depends on buffer capacity, however the buffering of airway secretions has not been well characterized. In this work we develop a method for titrating micro-scale (30 ?l) volumes and use it to study fluid secreted by the human airway epithelial cell line Calu-3, a widely used model for submucosal gland serous cells. Microtitration curves revealed that HCO?3 is the major buffer. Peak buffer capacity (?) increased from 17 to 28 mM/pH during forskolin stimulation, and was reduced by >50% in fluid secreted by cystic fibrosis transmembrane conductance regulator (CFTR)-deficient Calu-3 monolayers, confirming an important role of CFTR in HCO?3 secretion. Back-titration with NaOH revealed non-volatile buffer capacity due to proteins synthesized and released by the epithelial cells. Lysozyme and mucin concentrations were too low to buffer Calu-3 fluid significantly, however model titrations of porcine gastric mucins at concentrations near the sol-gel transition suggest that mucins may contribute to the buffer capacity of ASL in vivo. We conclude that CFTR-dependent HCO?3 secretion and epithelially-derived proteins are the predominant buffers in Calu-3 secretions.

Kim, Dusik; Liao, Jie; Hanrahan, John W.

2014-01-01

256

Buffer control scheme in multimedia synchronization  

Microsoft Academic Search

We present a complete synchronization scheme for multimedia information systems. The playout schedule is ensured by setting medium retrieval schedule based on the suitable control time at each different medium servers and by providing a suitable buffer for each medium at the client side. Because of the asynchronous nature of the network and the host operating system, certain buffer management

A. Hac; Cindy X. Xue

1997-01-01

257

The influence of ammonium on nitrate reduction in wheat seedlings  

Microsoft Academic Search

Ammonium markedly inhibited nitrate absorption by nitrogenstarved wheat seedlings but did not decrease the proportion of absorbed nitrate that was reduced. Seedlings high in nitrate (absorbed prior to the experimental periods) reduced similar amounts of this nitrate regardless of whether or not ammonium was present and being absorbed during the period of measurement. Ammonium or products of ammonium assimilation did

P. L. Minotti; Doris Craig Williams; W. A. Jackson

1969-01-01

258

Optimization of protein buffer cocktails using Thermofluor.  

PubMed

The stability and homogeneity of a protein sample is strongly influenced by the composition of the buffer that the protein is in. A quick and easy approach to identify a buffer composition which increases the stability and possibly the conformational homogeneity of a protein sample is the fluorescence-based thermal-shift assay (Thermofluor). Here, a novel 96-condition screen for Thermofluor experiments is presented which consists of buffer and additive parts. The buffer screen comprises 23 different buffers and the additive screen includes small-molecule additives such as salts and nucleotide analogues. The utilization of small-molecule components which increase the thermal stability of a protein sample frequently results in a protein preparation of higher quality and quantity and ultimately also increases the chances of the protein crystallizing. PMID:23385769

Reinhard, Linda; Mayerhofer, Hubert; Geerlof, Arie; Mueller-Dieckmann, Jochen; Weiss, Manfred S

2013-02-01

259

[Mechanical buffering characteristics of feline paw pads].  

PubMed

In the long time of natural evolution, the bodies of some animals, such as feline, that live in the wild and complicate surroundings have evolved to possess outstanding buffering characteristics, which make the animals adapt to the environment perfectly. These animals generally have well-developed paw pads under their soles to play an important role in attenuating the intensity of impact when they land on the ground. Investigating the buffering characteristics of these animals' paw pads could help us to design "bionic" buffering and energy-absorption devices. In this paper, based on observations of animal jumping test, a simple mass-spring-buffer model was proposed to explore the buffering characteristics of the animals' paw pads. By analytically solving the differential equations of this model, the parameters concerned with paw pads functions were discussed and some significant results were obtained. PMID:23469538

Zhang, Xiaopeng; Yang, Jialing; Yu, Hui

2012-12-01

260

No effect of bicarbonate treatment on insulin sensitivity and glucose control in non-diabetic older adults.  

PubMed

Chronic mild metabolic acidosis is common among older adults, and limited evidence suggests that it may contribute to insulin resistance and type-2 diabetes. This analysis was conducted to determine whether bicarbonate supplementation, an alkalinizing treatment, improves insulin sensitivity or glucose control in non-diabetic older adults. Fasting blood glucose and insulin were measured in stored samples from subjects who had completed a 3-month clinical trial of bicarbonate supplementation to improve indicators of bone and muscle health. One hundred and fifty three ambulatory, non-diabetic adults aged 50 years and older were studied. Subjects were randomized to one of two bicarbonate groups (67.5 mmol/day of potassium bicarbonate or sodium bicarbonate) or to one of two no-bicarbonate groups (67.5 mmol/day of placebo or potassium chloride). Subjects remained on treatment throughout the 3-month study. The primary outcome measures were changes in fasting plasma glucose, serum insulin and HOMA-IR, an index of insulin resistance. Bicarbonate supplementation reduced net acid excretion (adjusted mean±SEM for the change in NAE/creatinine, mmol/mmol, was 0.23±0.22 in the no-bicarbonate group compared with -3.53±0.22 in the bicarbonate group, P<0.001) but had no effect on fasting plasma glucose, serum insulin, or HOMA-IR. In conclusion, bicarbonate supplementation does not appear to improve insulin sensitivity or glucose control in non-diabetic older adults. PMID:21046483

Harris, Susan S; Dawson-Hughes, Bess

2010-10-01

261

Sorption of quaternary ammonium compounds to municipal sludge  

Microsoft Academic Search

The sorptive behavior of four quaternary ammonium compounds (QACs) – hexadecyl trimethyl ammonium chloride (C16TMA), dodecyl trimethyl ammonium chloride (C12TMA), hexadecyl benzyl dimethyl ammonium chloride (C16BDMA), and dodecyl benzyl dimethyl ammonium chloride (C12BDMA) – to municipal primary, waste activated, mesophilic digested, and thermophilic digested sludges was assessed at 22°C. Batch adsorption of all four separately tested QACs to primary sludge

Zainab Z. Ismail; Ulas Tezel; Spyros G. Pavlostathis

2010-01-01

262

Plasma exchange successfully treats central pontine myelinolysis after acute hypernatremia from intravenous sodium bicarbonate therapy  

PubMed Central

Background Osmotic demyelination syndrome (ODS) primarily occurs after rapid correction of severe hyponatremia. There are no proven effective therapies for ODS, but we describe the first case showing the successful treatment of central pontine myelinolysis (CPM) by plasma exchange, which occurred after rapid development of hypernatremia from intravenous sodium bicarbonate therapy. Case presentation A 40-year-old woman presented with general weakness, hypokalemia, and metabolic acidosis. The patient was treated with oral and intravenous potassium chloride, along with intravenous sodium bicarbonate. Although her bicarbonate deficit was 365 mEq, we treated her with an overdose of intravenous sodium bicarbonate, 480 mEq for 24 hours, due to the severity of her acidemia and her altered mental status. The next day, she developed hypernatremia with serum sodium levels rising from 142.8 mEq/L to 172.8 mEq/L. Six days after developing hypernatremia, she exhibited tetraparesis, drooling, difficulty swallowing, and dysarthria, and a brain MRI revealed high signal intensity in the central pons with sparing of the peripheral portion, suggesting CPM. We diagnosed her with CPM associated with the rapid development of hypernatremia after intravenous sodium bicarbonate therapy and treated her with plasma exchange. After two consecutive plasma exchange sessions, her neurologic symptoms were markedly improved except for mild diplopia. After the plasma exchange sessions, we examined the patient to determine the reason for her symptoms upon presentation to the hospital. She had normal anion gap metabolic acidosis, low blood bicarbonate levels, a urine pH of 6.5, and a calyceal stone in her left kidney. We performed a sodium bicarbonate loading test and diagnosed distal renal tubular acidosis (RTA). We also found that she had Sjögren’s syndrome after a positive screen for anti-Lo, anti-Ra, and after the results of Schirmer’s test and a lower lip biopsy. She was discharged and treated as an outpatient with oral sodium bicarbonate and potassium chloride. Conclusion This case indicates that serum sodium concentrations should be carefully monitored in patients with distal RTA receiving intravenous sodium bicarbonate therapy. We should keep in mind that acute hypernatremia and CPM can be associated with intravenous sodium bicarbonate therapy, and that CPM due to acute hypernatremia may be effectively treated with plasma exchange.

2014-01-01

263

Influence of calcium ions on the crystallization of sodium bicarbonate  

NASA Astrophysics Data System (ADS)

In industrial crystallization of sodium bicarbonate (sodium hydrogenocarbonate), the presence of calcium ions in solutions is unavoidable due to the production process. The understanding of the Ca 2+ role in NaHCO 3 crystallization would be helpful for improving the quality of the final products. The influence of calcium ions on NaHCO 3 crystallization was investigated in a 5-l mixed suspension mixed product removal crystallizer under controlled conditions. A density meter was used for continuous supersaturation monitoring. After a steady state had been reached, different CaCl 2 amounts were added at a constant flow rate. It was found that limited calcium ion levels in the system reduce drastically the nucleation frequency of NaHCO 3 and has a limited influence on crystal growth rate. The supersaturation measurements and other methods confirmed this phenomenon. The relationship between the Ca 2+ influence on NaHCO 3 crystallization, the calcium carbonate solubility and its metastable zone in concentrated NaHCO 3 solution was established. In fact, Ca 2+ has a maximum effect on NaHCO 3 crystallization kinetics when the saturation of calcium carbonate in NaHCO 3 solution has been reached, and the effect is constant in the metastable zone. The excess of Ca 2+ precipitates in NaHCO 3 solution as CaCO 3, as observed by energy dispersive X-ray and X-ray diffraction. This explained why an increasing Ca 2+ concentration in the solution has a limited influence on NaHCO 3 crystal size distribution and habit, but decreases the crystal purity. It is also confirmed that an impurity as Ca 2+ has no influence on the equilibrium NaHCO 3-Na 2CO 3.

Zhu, Yi; Demilie, Paul; Davoine, Perrine; Cartage, Thierry; Delplancke-Ogletree, Marie-Paule

2005-02-01

264

Two fluoroalcohols as components of basic buffers for liquid chromatography electrospray ionization mass spectrometric determination of antibiotic residues.  

PubMed

Two fluoroalcohols--1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol (HFTB)--were evaluated for the first time as volatile buffer acids in the basic mobile phase for reversed-phase chromatography with electrospray ionization-mass spectrometric (LC-ESI-MS) detection of five antibiotics. Chromatographic separation as well as positive and negative ion ESI-MS intensities using these novel buffer components were compared to traditional buffer systems. Overall, the highest signal intensities and best chromatographic separation for the five antibiotics (ciprofloxacin, norfloxacin, ofloxacin, sulfadimethoxine and sulfamethoxazole) were achieved using 5 mM HFIP as the buffer acid to methanol : water mobile phase (pH of the aqueous component adjusted to 9.0 with ammonium hydroxide). Comparable results were achieved using 5 mM HFTB (pH adjusted to 9.0 with ammonium hydroxide). The suitability of HFIP for analysis of antibiotic residues in lettuce is demonstrated. PMID:21922097

Kipper, Karin; Herodes, Koit; Leito, Ivo; Nei, Lembit

2011-11-01

265

The thermal decomposition behavior of ammonium perchlorate and of an ammonium-perchlorate-based composite propellant  

Microsoft Academic Search

The thermal decomposition of ammonium perchlorate (AP) and ammonium-perchlorate-based composite propellants is studied using the simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) technique. The main objective of the present work is to evaluate whether the STMBMS can provide new data on these materials that will have sufficient detail on the reaction mechanisms and associated reaction kinetics to permit creation of

R. Behrens; L. Minier

1998-01-01

266

Ammonium triggers lateral root branching in Arabidopsis in an AMMONIUM TRANSPORTER1;3-dependent manner.  

PubMed

Root development is strongly affected by the plant's nutritional status and the external availability of nutrients. Employing split-root systems, we show here that local ammonium supply to Arabidopsis thaliana plants increases lateral root initiation and higher-order lateral root branching, whereas the elongation of lateral roots is stimulated mainly by nitrate. Ammonium-stimulated lateral root number or density decreased after ammonium or Gln supply to a separate root fraction and did not correlate with cumulative uptake of (15)N-labeled ammonium, suggesting that lateral root branching was not purely due to a nutritional effect but most likely is a response to a sensing event. Ammonium-induced lateral root branching was almost absent in a quadruple AMMONIUM TRANSPORTER (qko, the amt1;1 amt1;2 amt1;3 amt2;1 mutant) insertion line and significantly lower in the amt1;3-1 mutant than in the wild type. Reconstitution of AMT1;3 expression in the amt1;3-1 or in the qko background restored higher-order lateral root development. By contrast, AMT1;1, which shares similar transport properties with AMT1;3, did not confer significant higher-order lateral root proliferation. These results show that ammonium is complementary to nitrate in shaping lateral root development and that stimulation of lateral root branching by ammonium occurs in an AMT1;3-dependent manner. PMID:21119058

Lima, Joni E; Kojima, Soichi; Takahashi, Hideki; von Wirén, Nicolaus

2010-11-01

267

Sediment retention in rangeland riparian buffers.  

PubMed

Controlling nonpoint-source sediment pollution is a common goal of riparian management, but there is little quantitative information about factors affecting performance of rangeland riparian buffers. This study evaluated the influence of vegetation characteristics, buffer width, slope, and stubble height on sediment retention in a Montana foothills meadow. Three vegetation types (sedge wetland, rush transition, bunchgrass upland) were compared using twenty-six 6- x 2-m plots spanning 2 to 20% slopes. Plots were clipped moderately (10-15 cm stubble) or severely (2-5 cm stubble). Sediment (silt + fine sand) was added to simulated overland runoff 6, 2, or 1 m above the bottom of each plot. Runoff was sampled at 15-s to > 5-min intervals until sediment concentrations approached background levels. Sediment retention was affected strongly by buffer width and moderately by vegetation type and slope, but was not affected by stubble height. Mean sediment retention ranged from 63 to > 99% for different combinations of buffer width and vegetation type, with 94 to 99% retention in 6-m-wide buffers regardless of vegetation type or slope. Results suggest that rangeland riparian buffers should be at least 6 m wide, with dense vegetation, to be effective and reliable. Narrower widths, steep slopes, and sparse vegetation increase risk of sediment delivery to streams. Vegetation characteristics such as biomass, cover, or density are more appropriate than stubble height for judging capacity to remove sediment from overland runoff, though stubble height may indirectly indicate livestock impacts that can affect buffer performance. PMID:12809315

Hook, Paul B

2003-01-01

268

Buffer-regulated biocorrosion of pure magnesium.  

PubMed

Magnesium (Mg) alloys are being actively investigated as potential load-bearing orthopaedic implant materials due to their biodegradability in vivo. With Mg biomaterials at an early stage in their development, the screening of alloy compositions for their biodegradation rate, and hence biocompatibility, is reliant on cost-effective in vitro methods. The use of a buffer to control pH during in vitro biodegradation is recognised as critically important as this seeks to mimic pH control as it occurs naturally in vivo. The two different types of in vitro buffer system available are based on either (i) zwitterionic organic compounds or (ii) carbonate buffers within a partial-CO(2) atmosphere. This study investigated the influence of the buffering system itself on the in vitro corrosion of Mg. It was found that the less realistic zwitterion-based buffer did not form the same corrosion layers as the carbonate buffer, and was potentially affecting the behaviour of the hydrated oxide layer that forms on Mg in all aqueous environments. Consequently it was recommended that Mg in vitro experiments use the more biorealistic carbonate buffering system when possible. PMID:22190196

Kirkland, Nicholas T; Waterman, Jay; Birbilis, Nick; Dias, George; Woodfield, Tim B F; Hartshorn, Richard M; Staiger, Mark P

2012-02-01

269

A novel structure of optical buffer  

NASA Astrophysics Data System (ADS)

Optical buffers are critical for low packet-loss probability in future photonic packet-switched networks. In particular, they would be required to store packets during rate conversion and header processing, and to overcome the receiver's bottleneck. They would be required for queuing packets while transmitters await access to the network. In this paper, we present a novel structure of optical buffer with compact size. This kind of optical buffer is based on a collinear 3x3 fiber coupler in which three fibers are completely in the same plane and weakly coupled. A SOA is used as its nonlinear element as well as an amplifier in it.The experiment result will be also given in the paper. Storage results obtained with this novel structure optical buffer at 100Mb/s will be presented first and then its capacity is extended to higher data rates of 2.5Gb/s, more compatible with present optical networks. Storage has been observed for time up to 1.568ms(more than 32 circulations) in both cases without obvious degration. The novel structure of optical buffer could be a more compact device which makes it possible to be integrated in a chip. SOA in the buffer is used as a nonlinear element as well as an amplifier to compensate loss in the buffer loop. The buffer needs low control power for switch operation. It is easy to control 'write' and 'erase' operation because the same TOAD switch in the buffer can be used for both 'write' and 'erase' operation.

Liu, AiMing; Wu, Chongqing; Gao, Huali; Gong, Yandong; Shum, Ping

2005-02-01

270

Effects of combined creatine and sodium bicarbonate supplementation on repeated sprint performance in trained men.  

PubMed

Creatine and sodium bicarbonate supplementation independently increase exercise performance, but it remains unclear whether combining these 2 supplements is more beneficial on exercise performance. The purpose of this study was to evaluate the impact of combining creatine monohydrate and sodium bicarbonate supplementation on exercise performance. Thirteen healthy, trained men (21.1 ± 0.6 years, 23.5 ± 0.5 kg·m(-2), 66.7 ± 5.7 ml·(kg·m)(-1) completed 3 conditions in a double-blinded, crossover fashion: (a) Placebo (Pl; 20 g maltodextrin + 0.5 g·kg(-1) maltodextrin), (b) Creatine (Cr; 20 g + 0.5 g·kg(-1) maltodextrin), and (c) Creatine plus sodium bicarbonate (Cr + Sb; 20 g + 0.5 g·kg(-1) sodium bicarbonate). Each condition consisted of supplementation for 2 days followed by a 3-week washout. Peak power, mean power, relative peak power, and bicarbonate concentrations were assessed during six 10-second repeated Wingate sprint tests on a cycle ergometer with a 60-second rest period between each sprint. Compared with Pl, relative peak power was significantly higher in Cr (4%) and Cr + Sb (7%). Relative peak power was significantly lower in sprints 4-6, compared with that in sprint 1, in both Pl and Cr. However, in Cr + Sb, sprint 6 was the only sprint significantly lower compared with sprint 1. Pre-Wingate bicarbonate concentrations were significantly higher in Cr + Sb (10%), compared with in Pl and Cr, and mean concentrations remained higher after sprint 6, although not significantly. Combining creatine and sodium bicarbonate supplementation increased peak and mean power and had the greatest attenuation of decline in relative peak power over the 6 repeated sprints. These data suggest that combining these 2 supplements may be advantageous for athletes participating in high-intensity, intermittent exercise. PMID:23254493

Barber, James J; McDermott, Ann Y; McGaughey, Karen J; Olmstead, Jennifer D; Hagobian, Todd A

2013-01-01

271

Calcium sulphate in ammonium sulphate solution  

USGS Publications Warehouse

Calcium sulphate, at 25?? C., is two-thirds as soluble in dilute (o.i mol per liter) and twice as soluble in concentrated (3 mois per liter) ammonium sulphate solution as in water. The specific electric conductivity of concentrated ammonium sulphate solutions is lessened by saturating with calcium sulphate. Assuming that dissociation of ammonium sulphate takes place into 2NH4?? and SO4" and of calcium sulphate into Ca and SO4" only, and that the conductivity is a measure of such dissociation, the solubility of calcium sulphate in dilute ammonium sulphate solutions is greater than required by the mass-law. The conductivity of the dilute mixtures may be accurately calculated by means of Arrhenius' principle of isohydric solutions. In the data obtained in these calculations, the concentration of non-dissociated calcium sulphate decreases with increasing ammonium sulphate. The work as a whole is additional evidence of the fact that we are not yet in possession of all the factors necessary for reconciling the mass-law to the behavior of electrolytes. The measurements above described were made in the chemical laboratory of the University of Michigan.

Sullivan, E. C.

1905-01-01

272

Acute sodium bicarbonate loading has negligible effects on resting and exercise blood pressure but causes gastrointestinal distress  

PubMed Central

Oral ingestion of sodium bicarbonate (bicarbonate loading) has acute ergogenic effects on short-duration, high-intensity exercise. Because sodium bicarbonate is 27% sodium, ergogenic doses (i.e. 300 mg·kg?1) result in sodium intakes well above the Dietary Reference Intakes upper limit of 2300 mg/day. Therefore, it is conceivable that bicarbonate loading could have hypertensive effects. Therefore, we performed a double-blind cross-over trial to evaluate the hypothesis that bicarbonate loading increases resting and exercise blood pressure (BP). A secondary hypothesis was that bicarbonate loading causes gastrointestinal distress. Eleven endurance-trained men and women (exercise frequency, 4.6±0.4 sessions/wk; duration, 65±6 min/session) underwent testing on two occasions in random sequence: once after bicarbonate loading (300 mg·kg?1) and once after placebo ingestion. BP and heart rate (HR) were measured before bicarbonate or placebo consumption, 30 minutes after consumption, during 20 min of steady state submaximal cycling exercise, and during recovery. Bicarbonate loading did not affect systolic BP during rest, exercise, or recovery (p=0.38 for main treatment effect). However, it resulted in modestly higher diastolic BP (main treatment effect, +3.3±1.1 mmHg, p=0.01) and higher HR (main treatment effect, +10.1±2.4 bpm, p=0.002). Global ratings of gastrointestinal distress severity (0–10 scale) were greater after bicarbonate ingestion (5.1±0.5 vs. 0.5±0.2, p<0.0001). Furthermore, 10 of the 11 subjects (91%) experienced diarrhea, 64% experience bloating and thirst, and 45% experienced nausea after bicarbonate loading. In conclusion, although a single, ergogenic dose of sodium bicarbonate does not appear to have acute, clinically important effects on resting or exercise BP, it does cause substantial GI distress.

Kahle, Laura E.; Kelly, Patrick V.; Eliot, Kathrin A.; Weiss, Edward P.

2013-01-01

273

Sodium-bicarbonate cotransport occurs in rat kidney cortical membranes but not in rat small intestinal basolateral membranes.  

PubMed Central

Basolateral membrane vesicles were isolated from rat kidney cortex and small intestinal enterocytes. Both membrane preparations show ATP-dependent calcium uptake and cytochalasin B-sensitive D-glucose transport. In renal membranes, sodium influx is stimulated by bicarbonate; bicarbonate-dependent sodium flux is membrane-potential-dependent and inhibited by 4,4'-di-isothiocyanato-2, 2'-stilbenedisulphanic acid ('DIDS'). Small intestinal basolateral membranes do not show bicarbonate-dependent sodium fluxes.

Hagenbuch, B; Stange, G; Murer, H

1987-01-01

274

Acute sodium bicarbonate loading has negligible effects on resting and exercise blood pressure but causes gastrointestinal distress.  

PubMed

Oral ingestion of sodium bicarbonate (bicarbonate loading) has acute ergogenic effects on short-duration, high-intensity exercise. Because sodium bicarbonate is 27% sodium, ergogenic doses (ie, 300 mg?kg?¹) result in sodium intakes well above the Dietary Reference Intakes upper limit of 2300 mg/day. Therefore, it is conceivable that bicarbonate loading could have hypertensive effects. Therefore, we performed a double-blind crossover trial to evaluate the hypothesis that bicarbonate loading increases resting and exercise blood pressure (BP). A secondary hypothesis was that bicarbonate loading causes gastrointestinal distress. Eleven endurance-trained men and women (exercise frequency, 4.6 ± 0.4 sessions/wk; duration, 65 ± 6 min/session) underwent testing on two occasions in random sequence: once after bicarbonate loading (300 mg?kg?¹) and once after placebo ingestion. BP and heart rate were measured before bicarbonate or placebo consumption, 30 minutes after consumption, during 20 min of steady state submaximal cycling exercise, and during recovery. Bicarbonate loading did not affect systolic BP during rest, exercise, or recovery (P = .38 for main treatment effect). However, it resulted in modestly higher diastolic BP (main treatment effect, +3.3 ± 1.1 mmHg, P = .01) and higher heart rate (main treatment effect, +10.1 ± 2.4 beats per minute, P = .002). Global ratings of gastrointestinal distress severity (0-10 scale) were greater after bicarbonate ingestion (5.1 ± 0.5 vs 0.5 ± 0.2, P < .0001). Furthermore, 10 of the 11 subjects (91%) experienced diarrhea, 64% experience bloating and thirst, and 45% experienced nausea after bicarbonate loading. In conclusion, although a single, ergogenic dose of sodium bicarbonate does not appear to have acute, clinically important effects on resting or exercise BP, it does cause substantial gastrointestinal distress. PMID:23746564

Kahle, Laura E; Kelly, Patrick V; Eliot, Kathrin A; Weiss, Edward P

2013-06-01

275

Automatic initialisation of buffer composition estimation for on-line analysis of unknown buffer solutions.  

PubMed

An automatic initialisation procedure for extracting useful information about buffer composition from a titration experiment is presented in this paper. The initialisation procedure identifies which buffering components are present in the sample from a relatively long list of buffers expected in the system monitored. The procedure determines approximate pKa values of the buffers and evaluates their maximum and minimum concentrations. This information is then used to start an optimisation procedure to fit the model of the buffer components to the titration data and to accurately determine buffer concentrations and pKa values. The procedure has been integrated as a software layer around the buffer capacity optimum model builder (BOMB) that fits a buffer-capacity model to a measured buffer-capacity curve to estimate model properties (pKa values and concentrations). The reliability and robustness of the resulting buffer capacity software (BCS) were tested using a titrimetric analyser simulator (TAS). The BCS was then validated off-line and on-line. PMID:16184364

Zaher, Usama E; Vanrolleghem, Peter A

2005-10-01

276

Spacecraft Optical Disk Recorder Memory Buffer Control.  

National Technical Information Service (NTIS)

The goal of this project is to develop an Application Specific Integrated Circuit (ASIC) for use in the control electronics of the Spacecraft Optical Disk Recorder (SODR). Specifically, this project is to design an extendable memory buffer controller ASIC...

R. F. Hodson

1992-01-01

277

Certifying the Absence of Buffer Overflows.  

National Technical Information Service (NTIS)

Despite increased awareness and efforts to reduce buffer overflows, they continue to be the cause of most software vulnerabilities. In large part, these problems are due to the widespread use of unsafe library routines among programmers. For reasons of ef...

S. Chaki S. Hissam

2006-01-01

278

Sodium bicarbonate supplementation improves hypertrophy-type resistance exercise performance.  

PubMed

The aim of the present study was to examine the effects of sodium bicarbonate (NaHCO(3)) administration on lower-body, hypertrophy-type resistance exercise (HRE). Using a double-blind randomized counterbalanced design, 12 resistance-trained male participants (mean ± SD; age = 20.3 ± 2 years, mass = 88.3 ± 13.2 kg, height = 1.80 ± 0.07 m) ingested 0.3 g kg(-1) of NaHCO(3) or placebo 60 min before initiation of an HRE regimen. The protocol employed multiple exercises: squat, leg press, and knee extension, utilizing four sets each, with 10-12 repetition-maximum loads and short rest periods between sets. Exercise performance was determined by total repetitions generated during each exercise, total accumulated repetitions, and a performance test involving a fifth set of knee extensions to failure. Arterialized capillary blood was collected via fingertip puncture at four time points and analyzed for pH, [HCO(3)(-)], base excess (BE), and lactate [Lac(-)]. NaHCO(3) supplementation induced a significant alkaline state (pH: NaHCO(3): 7.49 ± 0.02, placebo: 7.42 ± 0.02, P < 0.05; [HCO(3)(-)]: NaHCO(3): 31.50 ± 2.59, placebo: 25.38 ± 1.78 mEq L(-1), P < 0.05; BE: NaHCO(3): 7.92 ± 2.57, placebo: 1.08 ± 2.11 mEq L(-1), P < 0.05). NaHCO(3) administration resulted in significantly more total repetitions than placebo (NaHCO(3): 139.8 ± 13.2, placebo: 134.4 ± 13.5), as well as significantly greater blood [Lac(-)] after the exercise protocol (NaHCO(3): 17.92 ± 2.08, placebo: 15.55 ± 2.50 mM, P < 0.05). These findings demonstrate ergogenic efficacy for NaHCO(3) during HRE and warrant further investigation into chronic training applications. PMID:22941193

Carr, Benjamin M; Webster, Michael J; Boyd, Joseph C; Hudson, Geoffrey M; Scheett, Timothy P

2013-03-01

279

The use of sodium bicarbonate in oral hygiene products and practice.  

PubMed

Early dentifrices contained natural ingredients, mostly in coarse particle form, and were quite abrasive. Salts, either sodium chloride, sodium bicarbonate, or a mixture of both, have also been used for tooth cleaning because of their ready availability and low cost. Because of both their relatively low intrinsic hardness and their high solubility, another advantage is low abrasivity. Their biggest disadvantage is a salty, unpalatable taste. Many modern dentifrices that contain sodium bicarbonate, either as the sole abrasive or one of several, disguise the saltiness with flavoring and sweetening agents. An almost inverse relationship exists between the percentage of baking soda in a dentifrice and its abrasivity. Sodium bicarbonate has no anticaries activity per se but is compatible with fluoride. In high concentrations, sodium bicarbonate is bactericidal against most periodontal pathogens. Most clinical studies have not found significant differences in periodontal response to baking soda as compared with other commercial dentifrices, probably because of its rapid clearance from the gingival sulcus. Sodium bicarbonate may not be the "magic bullet" for curing dental diseases, but its safety (if ingested), low abrasivity, low cost, and compatibility with fluoride make it a consummate dentifrice ingredient. PMID:12017930

Newbrun, E

1997-01-01

280

The use of sodium bicarbonate in oral hygiene products and practice.  

PubMed

Early dentifrices contained natural ingredients, mostly in coarse particle form, and were quite abrasive. Salts, either sodium chloride, sodium bicarbonate, or a mixture of both, have also been used for tooth cleaning because of their ready availability and low cost. Because of both their relatively low intrinsic hardness and their high solubility, another advantage is low abrasivity. Their biggest disadvantage is a salty, unpalatable taste. Many modern dentifrices that contain sodium bicarbonate, either as the sole abrasive or one of several, disguise the saltiness with flavoring and sweetening agents. An almost inverse relationship exists between the percentage of baking soda in a dentifrice and its abrasivity. Sodium bicarbonate has no anticaries activity per se but is compatible with fluoride. In high concentrations, sodium bicarbonate is bactericidal against most periodontal pathogens. Most clinical studies have not found significant differences in periodontal response to baking soda as compared with other commercial dentifrices, probably because of its rapid clearance from the gingival sulcus. Sodium bicarbonate may not be the "magic bullet" for curing dental diseases, but its safety (if ingested), low abrasivity, low cost, and compatibility with fluoride make it a consummate dentifrice ingredient. PMID:11524863

Newbrun, E

1996-01-01

281

Baroreflex Buffering and Susceptibility to Vasoactive Drugs  

Microsoft Academic Search

Background—The overall effect of vasoactive drugs on blood pressure is determined by a combination of the direct effect on vascular tone and an indirect baroreflex-mediated effect, a baroreflex buffering of blood pressure. Differences in baroreflex function affect the responsiveness to vasoactive medications, particularly baroreflex buffering of blood pressure; however, the magnitude is not known. Methods and Results—We characterized baroreflex function

Jens Jordan; Jens Tank; John R. Shannon; Andre Diedrich; Axel Lipp; Christoph Schröder; Guy Arnold; Arya M. Sharma; Italo Biaggioni; David Robertson; Friedrich C. Luft

282

Implementing Virtual Buffer for Electric Power Grids  

Microsoft Academic Search

The electric power grid is a vital network for every aspect of our life. The lack of buffer between generation and consumption\\u000a makes the power grid unstable and fragile. While large scale power storage is not technically and economically feasible at\\u000a present stage, we argue that a virtual buffer could be effectively implemented through a demand side management strategy built

Rong Gao; Lefteri H. Tsoukalas

2007-01-01

283

Beltway Buffers: Avoiding the OS Traffic Jam  

Microsoft Academic Search

Beltway buffers are operating system I\\/O paths optimised for high-throughput network applications. The key architec- tural feature of Beltway buffers is that all I\\/O takes place in long-lived, allocation-free, shared ringbuffers. Advantages of this design are (1) improved throughput through system-wide copy, context-switch and allocation avoidance and judicious use of the data cache, (2) transparent integration of peripheral hardware and

Willem De Bruijn; Herbert Bos

2008-01-01

284

Efficient Quality-Based Playout Buffer Algorithm  

Microsoft Academic Search

Playout buffers are used in VoIP systems to compensate for network delay\\u000ajitter by making a trade-off between delay and loss. In this work we propose a\\u000aplayout buffer algorithm that makes the trade-off based on maximization of\\u000aconversational speech quality, aiming to keep the computational complexity\\u000alowest possible. We model the network delay using a Pareto distribution and\\u000ashow

Emine Zerrin Sakir; Christian Feldbauer

2009-01-01

285

Molecular doping of graphene with ammonium groups  

SciTech Connect

Successful doping of an electronic material entails the existence of stable dopant configurations that cause a shift in the Fermi level without altering significantly the electronic states of the host system. The selection of chemical groups that satisfy these conditions when adsorbed on graphene is still an open challenge. Here we show with first-principles calculations that ammonium groups meet the criteria of stable physisorption and efficient doping of graphene. We also describe processes of deactivation of ammonium dopants through their dissociation over graphene impurities or nanoribbon edges. Finally, we show that carbon nanotubes can be used to spatially confine the dopants and avert their edge-related de-activation.

Tsetseris, L. [Vanderbilt University; Pantelides, Sokrates T [ORNL

2012-01-01

286

On the evaporation of ammonium sulfate solution  

SciTech Connect

Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 {+-} 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.

Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

2009-07-16

287

On the evaporation of ammonium sulfate solution.  

PubMed

Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 +/- 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly. PMID:19861551

Drisdell, Walter S; Saykally, Richard J; Cohen, Ronald C

2009-11-10

288

Key Physiology of Anaerobic Ammonium Oxidation  

PubMed Central

The physiology of anaerobic ammonium oxidizing (anammox) aggregates grown in a sequencing batch reactor was investigated quantitatively. The physiological pH and temperature ranges were 6.7 to 8.3 and 20 to 43°C, respectively. The affinity constants for the substrates ammonium and nitrite were each less than 0.1 mg of nitrogen per liter. The anammox process was completely inhibited by nitrite concentrations higher than 0.1 g of nitrogen per liter. Addition of trace amounts of either of the anammox intermediates (1.4 mg of nitrogen per liter of hydrazine or 0.7 mg of nitrogen per liter of hydroxylamine) restored activity completely.

Strous, Marc; Kuenen, J. Gijs; Jetten, Mike S. M.

1999-01-01

289

ACS Science Data Buffer Check/Self-Tests for CS Buffer RAM and MIE RAM  

NASA Astrophysics Data System (ADS)

The ACS Science Buffer RAM is checked for bit flips during SAA passages. This is followed by a Control Section {CS} self-test consisting of writing/reading a specified bit pattern from each memory location in Buffer RAM and a similar test for MIE RAM. The MIE must be placed in BOOT mode for its self-test. The CS Buffer RAM self-test as well as the bit flip tests are all done with the CS in Operate.

Balzano, V.

2001-07-01

290

A Buffer that Mimics the SMP Buffer for Determining Lime Requirement of Soil  

Microsoft Academic Search

The Shoemaker-McLean-Pratt (SMP) buffer used for determining lime requirement of soil contains chromium and p-nitrophenol, which classifies the solution as a hazardous waste. A buffer without hazard- ous chemicals producing the same pH as SMP buffer would eliminate hazardous waste and have no effect on agronomic interpretation. Chemicals chosen to replace chromium and p-nitrophenol were 2-(N- morpholino)ethanesulfonic acid monohydrate (MES)

F. J. Sikora

2006-01-01

291

Growth evolution of ammonium oxotrifluorotitanate discoid crystal on glass prepared by ammonium hexafluorotitanate and boric acid  

NASA Astrophysics Data System (ADS)

A high quality ammonium oxofluorotitanate discoid crystal is grown on glass with an aqueous solution of ammonium hexafluorotitanate and boric acid in this study. The glass acts as a scavenger to enhance the nucleation of ammonium oxofluorotitanate crystal, and the growth evolution is examined. The composition and structure are examined by Raman spectroscopy, Fourier-transform infrared spectrometry, x-ray diffraction and high-resolution transmission electron microscopy. The discoid crystal shows high crystalline quality and composition uniformity. The energy bandgap is 3.7 eV.

Lee, Ming-Kwei; Shih, Tsung-Hsiang

2010-01-01

292

Survival after an amniotic fluid embolism following the use of sodium bicarbonate.  

PubMed

Amniotic fluid embolism (AFE) is a rare and potentially fatal complication of pregnancy. In this case report, we highlight the successful use of sodium bicarbonate in a patient with an AFE. We present a case of a 38-year-old mother admitted for an elective caesarean section. Following the delivery of her baby, the mother suffered a cardiac arrest. Following a protracted resuscitation, transoesophageal echocardiography demonstrated evidence of acute pulmonary hypertension, with an empty left ventricle and an over-distended right ventricle. In view of these findings and no improvement noted from on-going resuscitation, sodium bicarbonate was infused as a pulmonary vasodilator. Almost instantaneous return of spontaneous circulation was noted, with normalisation of cardiac parameters. We propose that in patients suspected with AFE and who have been unresponsive to advance cardiac life support measures, and where right ventricular failure is present with acidosis and/or hypercarbia, the use of sodium bicarbonate should be considered. PMID:24879737

Evans, Sorcha; Brown, Brigid; Mathieson, Matthew; Tay, Stan

2014-01-01

293

Use of sodium bicarbonate to treat tricyclic antidepressant-induced arrhythmias in a patient with alkalosis.  

PubMed Central

Sodium bicarbonate has been recommended for the treatment of arrhythmias induced by tricyclic antidepressants. It is unclear, however, whether this therapy is effective only in the presence of acidosis. A case is presented in which there was an immediate response to sodium bicarbonate in three episodes of ventricular tachycardia despite the presence of alkalosis on two of the three occasions. Given the poor response to conventional therapy of arrhythmias induced by tricyclic antidepressants the use of sodium bicarbonate may be reasonable even in the presence of alkalosis. However, in the presence of pre-existing respiratory or metabolic alkalosis, such therapy is not without risk, and it is suggested that it be reserved for life-threatening situations when the arrhythmia has failed to respond to hyperventilation or antiarrhythmics or both.

Molloy, D W; Penner, S B; Rabson, J; Hall, K W

1984-01-01

294

Deletion of the anion exchanger Slc26a4 (pendrin) decreases apical Cl?/HCO3? exchanger activity and impairs bicarbonate secretion in kidney collecting duct  

PubMed Central

The anion exchanger Pendrin, which is encoded by SLC26A4 (human)/Slc26a4 (mouse) gene, is localized on the apical membrane of non-acid-secreting intercalated (IC) cells in the kidney cortical collecting duct (CCD). To examine its role in the mediation of bicarbonate secretion in vivo and the apical Cl?/HCO3? exchanger in the kidney CCD, mice with genetic deletion of pendrin were generated. The mutant mice show the complete absence of pendrin expression in their kidneys as assessed by Northern blot hybridization, Western blot, and immunofluorescence labeling. Pendrin knockout (KO) mice display significantly acidic urine at baseline [pH 5.20 in KO vs. 6.01 in wild type (WT); P < 0.0001] along with elevated serum HCO3? concentration (27.4 vs. 24 meq/l in KO vs. WT, respectively; P < 0.02), consistent with decreased bicarbonate secretion in vivo. The urine chloride excretion was comparable in WT and KO mice. For functional studies, CCDs were microperfused and IC cells were identified by their ability to trap the pH fluorescent dye BCECF. The apical Cl?/HCO3? exchanger activity in B-IC and non-A, non-B-IC cells, as assessed by intracellular pH monitoring, was significantly reduced in pendrin-null mice. The basolateral Cl?/HCO3? exchanger activity in A-IC cells and in non-A, non-B-IC cells, was not different in pendrin KO mice relative to WT animals. Urine NH4+ (ammonium) excretion increased significantly, consistent with increased trapping of NH3 in the collecting duct in pendrin KO mice. We conclude that Slc26a4 (pendrin) deletion impairs the secretion of bicarbonate in vivo and reduces apical Cl?/HCO3? exchanger activity in B-IC and non-A, non-B-IC cells in CCD. Additional apical Cl?/HCO3? exchanger(s) is (are) present in the CCD.

Amlal, Hassane; Petrovic, Snezana; Xu, Jie; Wang, Zhaohui; Sun, Xuming; Barone, Sharon

2010-01-01

295

Effect of Beta-Alanine With and Without Sodium Bicarbonate on 2,000-m Rowing Performance.  

PubMed

Purpose: To examine the effect of beta-alanine only and beta-alanine with sodium bicarbonate supplementation on 2,000-m rowing performance. Methods: Twenty well-trained rowers (age 23 ± 4 y; height 1.85 ± 0.08 m; body mass 82.5 ± 8.9 kg) were assigned to either a placebo or beta-alanine (6.4 g·d-1 for 4 weeks) group. A 2,000-m rowing time trial (TT) was performed before supplementation (Baseline) and after 28 and 30 days of supplementation. The post supplementation trials involved supplementation with either maltodextrin or sodium bicarbonate in a double-blind, crossover design, creating four study conditions (placebo with maltodextrin; placebo with sodium bicarbonate; beta-alanine with maltodextrin; beta-alanine with sodium bicarbonate). Blood lactate, pH, bicarbonate, and base excess were measured pre-TT, immediately post-TT and at TT+5 min. Performance data were analyzed using magnitude based inferences. Results: Beta-alanine supplementation was very likely to be beneficial to 2,000-m rowing performance (6.4 ± 8.1 s effect compared with placebo), with the effect of sodium bicarbonate having a likely benefit (3.2 ± 8.8 s). There was a small (1.1 ± 5.6 s) but possibly beneficial additional effect when combining chronic beta-alanine supplementation with acute sodium bicarbonate supplementation compared with chronic beta-alanine supplementation alone. Sodium bicarbonate ingestion led to increases in plasma pH, base excess, bicarbonate, and lactate concentrations. Conclusions: Both chronic beta-alanine and acute sodium bicarbonate supplementation alone had positive effects on 2,000-m rowing performance. The addition of acute sodium bicarbonate to chronic beta-alanine supplementation may further enhance rowing performance. PMID:24172994

Hobson, Ruth M; Harris, Roger C; Martin, Dan; Smith, Perry; Macklin, Ben; Gualano, Bruno; Sale, Craig

2013-10-01

296

Erythrocyte lysis in isotonic solution of ammonium chloride: theoretical modeling and experimental verification.  

PubMed

A mathematical model of erythrocyte lysis in isotonic solution of ammonium chloride is presented in frames of a statistical approach. The model is used to evaluate several parameters of mature erythrocytes (volume, surface area, hemoglobin concentration, number of anionic exchangers on membrane, elasticity and critical tension of membrane) through their sphering and lysis measured by a scanning flow cytometer (SFC). SFC allows measuring the light-scattering pattern (indicatrix) of an individual cell over the angular range from 10 degrees to 60 degrees . Comparison of the experimentally measured and theoretically calculated light scattering patterns allows discrimination of spherical from non-spherical erythrocytes and evaluation of volume and hemoglobin concentration for individual spherical cells. Three different processes were applied for erythrocytes sphering: (1) colloid osmotic lysis in isotonic solution of ammonium chloride, (2) isovolumetric sphering in the presence of sodium dodecyl sulphate and albumin in neutrally buffered isotonic saline, and (3) osmotic fragility test in hypotonic media. For the hemolysis in ammonium chloride, the evolution of distributions of sphered erythrocytes on volume and hemoglobin content was monitored in real-time experiments. The analysis of experimental data was performed in the context of a statistical approach, taking into account that parameters of erythrocytes vary from cell to cell. PMID:18083194

Chernyshev, Andrey V; Tarasov, Peter A; Semianov, Konstantin A; Nekrasov, Vyacheslav M; Hoekstra, Alfons G; Maltsev, Valeri P

2008-03-01

297

Bicarbonate disruption of the pulmonary endothelial barrier via activation of endogenous soluble adenylyl cyclase, isoform 10.  

PubMed

It is becoming increasingly apparent that cAMP signals within the pulmonary endothelium are highly compartmentalized, and this compartmentalization is critical to maintaining endothelial barrier integrity. Studies demonstrate that the exogenous soluble bacterial toxin, ExoY, and heterologous expression of the forskolin-stimulated soluble mammalian adenylyl cyclase (AC) chimera, sACI/II, elevate cytosolic cAMP and disrupt the pulmonary microvascular endothelial barrier. The barrier-disruptive effects of cytosolic cAMP generated by exogenous soluble ACs are in contrast to the barrier-protective effects of subplasma membrane cAMP generated by transmembrane AC, which strengthens endothelial barrier integrity. Endogenous soluble AC isoform 10 (AC10 or commonly known as sAC) lacks transmembrane domains and localizes within the cytosolic compartment. AC10 is uniquely activated by bicarbonate to generate cytosolic cAMP, yet its role in regulation of endothelial barrier integrity has not been addressed. Here we demonstrate that, within the pulmonary circulation, AC10 is expressed in pulmonary microvascular endothelial cells (PMVECs) and pulmonary artery endothelial cells (PAECs), yet expression in PAECs is lower. Furthermore, pulmonary endothelial cells selectively express bicarbonate cotransporters. While extracellular bicarbonate generates a phosphodiesterase 4-sensitive cAMP pool in PMVECs, no such cAMP response is detected in PAECs. Finally, addition of extracellular bicarbonate decreases resistance across the PMVEC monolayer and increases the filtration coefficient in the isolated perfused lung above osmolality controls. Collectively, these findings suggest that PMVECs have a bicarbonate-sensitive cytosolic cAMP pool that disrupts endothelial barrier integrity. These studies could provide an alternative mechanism for the controversial effects of bicarbonate correction of acidosis of acute respiratory distress syndrome patients. PMID:23686854

Obiako, Boniface; Calchary, Wendy; Xu, Ningyong; Kunstadt, Ryan; Richardson, Bianca; Nix, Jessica; Sayner, Sarah L

2013-07-15

298

Intestinal bicarbonate secretion by marine teleost fish--why and how?  

PubMed

Intestinal fluids of most marine teleosts are alkaline (pH 8.4-9.0) and contain high levels of HCO(3)(-) equivalents (40-130 mM) which are excreted at a significant rate (>100 microEq kg(-1) h(-1)). Recent research reveals the following about this substantial HCO(3)(-) secretion: (1) It is not involved in acid-base regulation or neutralisation of stomach acid, but increases in parallel with drinking rate at elevated ambient salinities suggesting a role in osmoregulation; (2) In species examined so far, all sections of the intestine can secrete bicarbonate; (3) The secretion is dependent on mucosal Cl(-), sensitive to mucosal DIDS, and immuno-histochemistry indicates involvement of an apical Cl(-)/HCO(3)(-) exchanger. In addition, hydration of CO(2) via carbonic anhydrase in combination with proton extrusion appears to be essential for bicarbonate secretion. The mode of proton extrusion is currently unknown but potential mechanisms are discussed. One consequence of the luminal alkalinity and high bicarbonate concentrations is precipitation of calcium and magnesium as carbonate complexes. This precipitation is hypothesised to reduce the osmolality of intestinal fluids and thus play a potential role in water absorption and osmoregulation. The present studies on European flounder reveal that elevated luminal calcium (but not magnesium) concentrations stimulate intestinal bicarbonate secretion both acutely and chronically, in vitro and in vivo. At the whole animal level, the result of this elevated bicarbonate secretion was increased calcium precipitation with an associated reduction in the osmolality of rectal fluids and plasma. These observations suggest direct functional links between intestinal bicarbonate secretion, divalent cation precipitation and osmoregulation in marine teleost fish. PMID:12421549

Wilson, Rod W; Wilson, Jonathan M; Grosell, Martin

2002-11-13

299

Detonation Performance of Aluminium - Ammonium Nitrate Explosives  

Microsoft Academic Search

The research on an effect of aluminium contents on detonation characteristics of ammonium nitrate explosives was carried out. Measurements of detonation velocity were performed. Parameters of blast waves produced by charges of the investigated explosives detonating in an open space were measured by the use of piezoelectric gauges. Quasi-static pressure measurements were conducted in a steel chamber of 0.15 m

Józef PASZULA; Waldemar A. TRZCI?SKI

300

Ammonium in plant tissue: Real or artifact?  

Microsoft Academic Search

Tissue analysis of plant material is used to estimate the level of sufficiency or deficiency of any particular nutrient. Published values of ammoniumammonia reported in plant cell extracts would have been toxic to plants, if these values are really present in the cell. We believe that the ammonia determined in plant tissue is actually ammonium produced by the decomposition of

Uzi Kafkafi

1997-01-01

301

2-Arylacetic anhydrides as ammonium enolate precursors.  

PubMed

Readily prepared 2-arylacetic anhydrides act as convenient ammonium enolate precursors in isothiourea (HBTM-2.1)-mediated catalytic asymmetric intermolecular Michael addition-lactonisation processes, giving diverse synthetic building blocks in good yield with high diastereo- and enantiocontrol (up to 98?:?2 dr and >99% ee). PMID:24292454

Morrill, Louis C; Ledingham, Lyndsay A; Couturier, Jean-Philippe; Bickel, Jasmine; Harper, Andrew D; Fallan, Charlene; Smith, Andrew D

2014-01-28

302

21 CFR 184.1138 - Ammonium chloride.  

Code of Federal Regulations, 2013 CFR

...NH4 Cl, CAS Reg. No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution...strengthener as defined in § 170.3(o)(6) of this chapter; a flavor enhancer as defined in § 170.3(o)(11) of this...

2013-04-01

303

Stable Ammonium Bisulfate Clusters in the Atmosphere  

Microsoft Academic Search

Liquid drop model based equilibrium thermodynamics predicts that in the presence of even small ammonia concentrations practically all the atmospheric sulfuric acid molecules are bound to tiny, stable ammonium-bisulfate clusters. Hitherto sulfuric acid has been believed to form hydrates with water. Thermodynamic theory predicts correctly the hydrate formation observed experimentally. Results from ab initio computer simulations contradict the thermodynamic results

Hanna Vehkamäki; Ismo Napari; Markku Kulmala; Madis Noppel

2004-01-01

304

Diamond Head Revisited with Ammonium Dichromate.  

ERIC Educational Resources Information Center

The classroom demonstration using ammonium dichromate to simulate a volcanic eruption can be modified into a more dramatic and accurate representation of the geologic processes involved in the formation of a volcanic crater. The materials, demonstration setup, safety procedures, and applications to instruction are presented. (Author/WB)

Arrigoni, Edward

1981-01-01

305

Ammonium O,O-dicyclohexyl phosphorodithioate.  

PubMed

The structure of the title compound, NH4+.C12H22O2PS2-, consists of a polymeric arrangement of ammonium cations and O,O-dicyclohexyl phosphorodithioate anions linked through N-H...O and N-H...S hydrogen bonds. These interactions result in the formation of (100) sheets. PMID:16518052

Soylu, Mustafa Serkan; Ya?an, Mehtap; Cali?kan, Nezihe; Bati, Bekir; Büyükgüngör, Orhan

2006-03-01

306

Near infrared detection of ammonium minerals.  

USGS Publications Warehouse

Diagnostic near-infrared spectral features have been identified for minerals with ammonium (NH4+) bound in the crystal structure. Near-infrared detection of NH4-bearing minerals may provide useful information for prospecting for certain ore deposits and may provide a better understanding of the nitrogen cycle within geologic environments.-from Authors

Krohn, M. D.; Altaner, S. P.

1987-01-01

307

Permeation of ammonia across bilayer lipid membranes studied by ammonium ion selective microelectrodes.  

PubMed Central

Ammonium ion and proton concentration profiles near the surface of a planar bilayer lipid membrane (BLM) generated by an ammonium ion gradient across the BLM are studied by means of microelectrodes. If the concentration of the weak base is small compared with the buffer capacity of the medium, the experimental results are well described by the standard physiological model in which the transmembrane transport is assumed to be limited by diffusion across unstirred layers (USLs) adjacent to the membrane at basic pH values (pH > pKa) and by the permeation across the membrane itself at acidic pH values. In a poorly buffered medium, however, these predictions are not fulfilled. A pH gradient that develops within the USL must be taken into account under these conditions. From the concentration distribution of ammonium ions recorded at both sides of the BLM, the membrane permeability for ammonia is determined for BLMs of different lipid composition (48 x 10(-3) cm/s in the case of diphytanoyl phosphatidylcholine). A theoretical model of weak electrolyte transport that is based on the knowledge of reaction and diffusion rates is found to describe well the experimental profiles under any conditions. The microelectrode technique can be applied for the study of the membrane permeability of other weak acids or bases, even if no microsensor for the substance under study is available, because with the help of the theoretical model the membrane permeability values can be estimated from pH profiles alone. The accuracy of such measurements is limited, however, because small changes in the equilibrium constants, diffusion coefficients, or concentrations used for computations create a systematic error.

Antonenko, Y N; Pohl, P; Denisov, G A

1997-01-01

308

Association of Serum Bicarbonate Levels With Gait Speed and Quadriceps Strength in Older Adults  

PubMed Central

BACKGROUND Metabolic acidosis is associated with skeletal muscle proteolysis, and alkali supplementation has demonstrated improvements in lean body mass and urinary nitrogen wasting in several studies. However, the association of acidosis with functional outcomes has not been examined on a population-based level. STUDY DESIGN Cross-sectional study. SETTING & PARTICIPANTS 2,675 nationally representative adults 50 years of age and older in the National Health and Nutrition Examination Survey 1999 – 2002. FACTOR Serum bicarbonate level. OUTCOMES Low gait speed (gait speed) and low peak torque (peak torque) were defined as being in the lowest sex-specific quartile of gait speed and peak torque, respectively. MEASUREMENTS Serum bicarbonate was measured in all participants. gait speed was determined from a 20-foot timed walk. peak torque was calculated using peak isokinetic knee extensor force. RESULTS Serum bicarbonate <23 mEq/L was present in 22.7% of the cohort. Compared to participants with bicarbonate ?23 mEq/L, those with bicarbonate <23 mEq/L had higher body-mass index and serum albumin, were more likely to have low socioeconomic status, a diagnosis of diabetes mellitus, or glomerular filtration rate <60 mL/min/1.73 m2, and were less likely to use diuretics. Serum bicarbonate <23 mEq/L, compared with ?23 mEq/L, was associated with low gait speed (OR, 1.43; 95% confidence interval (CI), 1.04 – 1.95) and low peak torque (OR, 1.36; 95% CI, 1.07 – 1.74) after multivariable adjustment. The association with low peak torque was modified by race/ethnicity among women but not men (ORs of 1.52 (95% CI 1.08 – 2.13) for men, 2.33 (95% CI 1.23 – 4.44) for non- white women, and 0.93 (95% CI 0.47 – 1.82) for white women). LIMITATIONS Cross-sectional study using a single measurement of bicarbonate. CONCLUSIONS Lower serum bicarbonate levels are associated with slower gait speed and reduced quadriceps strength in older adults. Further studies should examine the effect of alkali therapy on functional outcomes.

Abramowitz, Matthew K.; Hostetter, Thomas H.; Melamed, Michal L.

2011-01-01

309

The Sodium-Driven Chloride/Bicarbonate Exchanger in Presynaptic Terminals  

PubMed Central

The sodium-driven chloride/bicarbonate exchanger (NDCBE), a member of the SLC4 family of bicarbonate transporters, was recently found to modulate excitatory neurotransmission in hippocampus. By using light and electron microscopic immunohistochemistry, we demonstrate here that NDCBE is expressed throughout the adult rat brain, and selectively concentrates in presynaptic terminals, where it is closely associated with synaptic vesicles. NDCBE is in most glutamatergic axon terminals, and is also present in the terminals of parvalbumin-positive ?-aminobutyric acid (GABA)ergic cells. These findings suggest that NDCBE can regulate glutamatergic transmission throughout the brain, and point to a role for NDCBE as a possible regulator of GABAergic neurotransmission.

Burette, Alain C.; Weinberg, Richard J.; Sassani, Patrick; Abuladze, Natalia; Kao, Liyo; Kurtz, Ira

2013-01-01

310

EXCHANGE PROPERTIES OF AMMONIUM SALTS OF 12-HETEROPOLYACIDS. V. SORPTION OF ALKALI METALS ON AMMONIUM PHOSPHOMOLYBDATOTUNGSTATE  

Microsoft Academic Search

The exchange properties of ammonium salts of phosphomolybdatotungstic ; acid (NHâPMoW) with various molar ratios of Mo: W are described. The ; uptake of cesium and rubidium is shown. Goed separation was obtained. (M.C.G.);

J. Krtil; I. Krivy

1963-01-01

311

Ammonium Sulfate Coprecipitation Antibody Determination with Purified Staphylococcal Enterotoxins.  

National Technical Information Service (NTIS)

The ammonium sulfate coprecipitation technique of Farr was applied to purified enterotoxins of Staphylococcus aureus. Studies with iodine 131-labeled enterotoxins A, B, and C, using 1.6 M ammonium sulfate for coprecipitation, revealed differences in the a...

J. Gruber G. G. Wright

1969-01-01

312

THE EFFECT OF ORGANOPHOSPHORUS PESTICIDES ON ESTUARINE AMMONIUM OXIDIZERS  

EPA Science Inventory

The effects of seven thiophosphorus pesticides and their degradation products on estuarine ammonium oxidizers were examined. Using an axenic, closed-culture, high cell density assay, the pesticides caused little inhibition of ammonium oxidation. However, the degradation product o...

313

Thermodynamics of Aqueous Solutions of Quaternary Ammonium Salts.  

National Technical Information Service (NTIS)

Activity and osmotic coefficients were determined by the isopiestic method, and density measurements were made in order to determine partial molal volumes. The solute salts were n-tetra-butyl ammonium bromide and fluoride, tetra methyl ammonium fluoride, ...

W. Y. Wen

1965-01-01

314

Technology for processing ammonium rhodanide of coking plants into high-purity ammonium thiocyanate and thiourea  

SciTech Connect

The regularities of the reversible reaction of isomerization of ammonium thiocyanate (NH{sub 4}NCS) into thiourea (NH{sub 2}){sub 2}CS, and the reverse reaction, were analyzed. An ecologically clean and highly efficient method for the extraction, purification, separation, and production of isomers from the coal byproduct ammonium thiocyanate was developed based on the measured volatilities of NH{sub 4}NCS and (NH{sub 2}){sub 2}CS.

Urakaev, F.K. [Institute of Geology & Mineral SB RAS, Novosibirsk (Russian Federation)

2009-04-15

315

Modelling growth responses of soil nitrifiers to additions of ammonium sulphate and ammonium chloride  

Microsoft Academic Search

Summary Following the addition of 0–75 ?mole N g?1 as ammonium chloride or ammonium sulphate to a sandy loam soil the nitrate formed was measured daily for a period of 15–17 days. The nitrate produced as a function of time was described using the Monod equation for microbial growth. An optimisation technique is described for obtaining, from the nitrification time

P. R. Darrah; P. H. Nye; R. E. White

1985-01-01

316

Lower serum bicarbonate and a higher anion gap are associated with lower cardiorespiratory fitness in young adults  

PubMed Central

Lower levels of serum bicarbonate and a higher anion gap have been associated with insulin resistance and hypertension in the general population. Whether these associations extend to other cardiovascular disease risk factors is unknown. To clarify this, we examined the association of serum bicarbonate and anion gap with cardiorespiratory fitness in 2714 adults aged 20–49 years in the 1999–2004 National Health and Nutrition Examination Survey. The mean serum bicarbonate was 24.6 mEq/L and the mean anion gap was 10.26 mEq/L, with fitness determined by submaximal exercise testing. After multivariable adjustment, gender, length of fasting, soft drink consumption, systolic blood pressure, serum phosphate, and hemoglobin were independently associated with both the serum bicarbonate and the anion gap. Low fitness was most prevalent among those in the lowest quartile of serum bicarbonate or highest quartile of anion gap. After multivariable adjustment, a one standard deviation higher serum bicarbonate or anion gap was associated with an odds ratio for low fitness of 0.80 (95% CI 0.70–0.91) and 1.30 (95% CI 1.15–1.48), respectively. The association of bicarbonate with fitness may be mediated by differences in lean body mass. Thus, lower levels of serum bicarbonate and higher levels of anion gap are associated with lower cardiorespiratory fitness in adults aged 20–49 years in the general population.

Abramowitz, Matthew K.; Hostetter, Thomas H.; Melamed, Michal L.

2012-01-01

317

Control of Citrus Green Mold by Carbonate and Bicarbonate Salts and the Influence of Commercial Postharvest Practices on Their Efficacy  

Microsoft Academic Search

Smilanick, J. L., Margosan, D. A., Mlikota, F., Usall, J., and Michael, I. F. 1999. Control of citrus green mold by carbonate and bicarbonate salts and the influence of commercial posthar- vest practices on their efficacy. Plant Dis. 83: 139-145. The toxicity to Penicillium digitatum and practical use of carbonate and bicarbonate salts to control green mold were determined. The

Joseph L. Smilanick; Dennis A. Margosan; Franka Mlikota; Josep Usall; Ibrahim F. Michael

1999-01-01

318

How does glutamine synthetase activity determine plant tolerance to ammonium?  

Microsoft Academic Search

The wide range of plant responses to ammonium nutrition can be used to study the way ammonium interferes with plant metabolism\\u000a and to assess some characteristics related with ammonium tolerance by plants. In this work we investigated the hypothesis\\u000a of plant tolerance to ammonium being related with the plants’ capacity to maintain high levels of inorganic nitrogen assimilation\\u000a in the

C. Cruz; A. F. M. Bio; M. D. Domínguez-Valdivia; P. M. Aparicio-Tejo; C. Lamsfus; M. A. Martins-Loução

2006-01-01

319

Contribution of ammonium ions to the lethality and antimetamorphic effects of ammonium perchlorate.  

PubMed

Ammonium perchlorate (AP) is a widespread military waste product in the United States and is a potent thyroid function disruptor in all vertebrates tested thus far. To determine the relative contribution of ammonium ions to the toxicity of AP, we exposed embryonic and larval Xenopus laevis to various concentrations of sodium perchlorate (SP) or ammonium chloride (AC). Ammonium perchlorate was significantly more lethal than SP; 5-d LC50s were 83 and 2,780 mg/L, respectively. To determine whether ammonium ions contribute to the antithyroid effects of AP, we exposed embryonic and larval X. laevis to two sublethal, environmentally relevant concentrations of AP or identical concentrations of AC or SP. At the smaller concentration, only AP delayed metamorphosis and reduced hindlimb growth. Sodium perchlorate and AP, but not AC, prevented metamorphosis and reduced hindlimb growth at the greater concentration. Although AP was slightly more effective in reducing outward manifestations of thyroid disruption, both perchlorate salts, unlike AC, caused profound histopathologic changes in the thyroid. Exposure to the higher concentration of either perchlorate salt produced a feminizing effect, resulting in a skewed sex ratio. We conclude that ammonium ions contribute significantly to the toxicity of AP but not to the direct antithyroid effects of perchlorate. PMID:16629145

Goleman, Wanda L; Carr, James A

2006-04-01

320

Effects of buffers on milk fatty acids and mammary arteriovenous differences in dairy cows fed Ca salts of fatty acids.  

PubMed

Ten Holstein cows in early lactation were used in a replicated 5 x 5 Latin square design to study the effects of MgO and three buffers added to diets containing Ca salts of canola oil fatty acids. Treatments were 1) control (basal diet; no buffer). 2) 1.1% NaHCO3 plus 1.1% KHCO3, 3) 1.9% NaHCO3, 4) 0.5% MgO, and 5) 2.0% Na sesquicarbonate (percentage of dry matter). The control diet contained 53% grass silage, 43% concentrate, and 4% Ca salts. Body weight, intake, milk yield, and percentages of milk fat, protein, and lactose were unaffected by treatments. Buffers and MgO tended to increase triacylglycerol extraction by the mammary gland and changed the proportions of some fatty acids in milk. Arterial concentrations of acetate and triacylglycerol were correlated with their respective arteriovenous differences. Extraction by the mammary gland was high for acetate (approximately equal to 58.2%), triacylglycerol (approximately equal to 47.3%) propionate (approximately equal to 34.6%), and glucose (approximately equal to 24.3%). Extraction of free fatty acids, phospholipids, or cholesterol was negligible. Mammary triacylglycerol arteriovenous difference tended to be higher than when MgO was fed than when NaHCO3 was fed. Sodium sesquicarbonate, NaHCO3, and the blend of bicarbonate buffers increased C18:2 in milk fat when compared with the control treatment. The concentration of C18:2 in milk fat decreased when MgO was fed, but the ratio of cis-C18:1 to trans-C18:1 increased compared with effects of dietary NaHCO3. Medium-chain fatty acids in milk fat tended to be higher than Na sesquicarbonate than with NaHCO3. Buffers and MgO modified the profiles of fatty acids in milk. PMID:9710770

Thivierge, M C; Chouinard, P Y; Lévesque, J; Girard, V; Seoane, J R; Brisson, G J

1998-07-01

321

75 FR 14082 - Ammonium Salts of Fatty Acids (C8  

Federal Register 2010, 2011, 2012, 2013

...the active ingredient ammonium salts of higher fatty acids (C ...requiring a tolerance for ammonium salts of fatty acids (C 8 -C...is established for Ammonium salts of fatty acids (C 8 -C...approval under the Paperwork Reduction Act (PRA),...

2010-03-24

322

Enhancement of activated sludge performance on ammonium removal by clinoptilolite  

Microsoft Academic Search

This study evaluated the influence of clinoptilolite on the performance of activated sludge system shocked by high concentration of ammonium. The ammonium and chemical oxygen demand (COD) removal from the experimental reactor containing clinoptilolite and from the clinoptilolite-free control reactor was determined. The ammonium and COD removal was approximately 8 and 20% higher in the experimental reactor than in the

Bing Xie; Xingchun Dai; Yatong Xu

2006-01-01

323

Integration of Anaerobic Ammonium Oxidation, Methanogensis and Denitrification  

Microsoft Academic Search

If EGSB reactor was inoculated with the aerobic activated sludge, then after the reactor start-up operation of 120 d, Granular sludge can be formed. Denitrification bacteria and anaerobic ammonium oxidation bacteria were cultured and enriched for 270 d in EGSB reactor with nitrite and ammonium. The removal efficiency of COD was 85%, ammonium nitrogen 35%, nitrite nitrogen 99.9%, and total

Zu Bo; Shiqiang Wei

2011-01-01

324

21 CFR 573.560 - Iron ammonium citrate.  

Code of Federal Regulations, 2013 CFR

...Drugs 6 2013-04-01 2013-04-01 false Iron ammonium citrate. 573.560 Section 573.560...OF ANIMALS Food Additive Listing § 573.560 Iron ammonium citrate. Iron ammonium citrate may be safely used in animal...

2013-04-01

325

40 CFR 721.6070 - Alkyl phosphonate ammonium salts.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Alkyl phosphonate ammonium salts. 721.6070 Section 721.6070 ...721.6070 Alkyl phosphonate ammonium salts. (a) Chemical substances and significant...generically as alkyl phosphonate ammonium salts (PMNs P-93-725 and...

2012-07-01

326

40 CFR 721.6070 - Alkyl phosphonate ammonium salts.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Alkyl phosphonate ammonium salts. 721.6070 Section 721.6070 ...721.6070 Alkyl phosphonate ammonium salts. (a) Chemical substances and significant...generically as alkyl phosphonate ammonium salts (PMNs P-93-725 and...

2010-07-01

327

[Preparation and testing of buffers for fibrinogen].  

PubMed

Chloride-citrate-glucose solution was used in fibrinogen preparation for intravenous administration. Concentrated hydrochloric acid previously used for preparation of buffers for fibrinogen has been replaced by the diluted one enabling easier and more precise buffer pH regulation and faster fibrinogen dissolution. Procedure for spectrophotometric determination of the total citrate ion buffer system, sodium-citrate and citric acid was developed. Obtained results were within the prescribed limits but the ones obtained by officinal titration in non-aqueous medium were significantly decreased. Glucose was determined before sterilization by polymetric, and after sterilization by iodometric procedure. Chloride content was determined by coulometric titration and sodium content by flame photometry. Used analytic methods are simple and obtained results accurate and reproducible. PMID:8553608

Poprzen, V; Popovi?, R; Antunovi?, M

1994-01-01

328

Liquid-liquid phase separation in particles containing organics mixed with ammonium sulfate, ammonium bisulfate, ammonium nitrate or sodium chloride  

NASA Astrophysics Data System (ADS)

As the relative humidity varies from high to low values in the atmosphere, particles containing organic species and inorganic salts may undergo liquid-liquid phase separation. The majority of the laboratory work on this subject has used ammonium sulfate as the inorganic salt. In the following we studied liquid-liquid phase separation in particles containing organics mixed with the following salts: ammonium sulfate, ammonium bisulfate, ammonium nitrate and sodium chloride. In each experiment one organic was mixed with one inorganic salt and the liquid-liquid phase separation relative humidity (SRH) was determined. Since we studied 23 different organics mixed with four different salts, a total of 92 different particle types were investigated. Out of the 92 types, 49 underwent liquid-liquid phase separation. For all the inorganic salts, liquid-liquid phase separation was never observed when the oxygen-to-carbon elemental ratio (O : C) ≥ 0.8 and was always observed for O : C < 0.5. For 0.5 ≤ O : C < 0.8, the results depended on the salt type. Out of the 23 organic species investigated, the SRH of 20 organics followed the trend: (NH4)2SO4 ≥ NH4HSO4 ≥ NaCl ≥ NH4NO3. This trend is consistent with previous salting out studies and the Hofmeister series. Based on the range of O : C values found in the atmosphere and the current results, liquid-liquid phase separation is likely a frequent occurrence in both marine and non-marine environments.

You, Y.; Renbaum-Wolff, L.; Bertram, A. K.

2013-12-01

329

Liquid-liquid phase separation in particles containing organics mixed with ammonium sulfate, ammonium bisulfate, ammonium nitrate or sodium chloride  

NASA Astrophysics Data System (ADS)

As the relative humidity varies from high to low values in the atmosphere, particles containing organics and inorganic salts may undergo liquid-liquid phase separation. The majority of the laboratory work on this subject has used ammonium sulfate as the inorganic salt. In the following we studied liquid-liquid phase separation in particles containing organics mixed with the following salts: ammonium sulfate, ammonium bisulfate, ammonium nitrate and sodium chloride. In each experiment one organic was mixed with one inorganic salt and the liquid-liquid phase separation relative humidity (SRH) was determined. Since we studied 23 different organics mixed with four different salts, a total of 92 different particle types were investigated. Out of the 92 types, 49 underwent liquid-liquid phase separation. For all the inorganic salts, liquid-liquid phase separation was never observed when the oxygen-to-carbon elemental ratio (O:C) was ? 0.8 and was always observed for O:C<0.5. For 0.5 ? O:C< 0.8, the results depended on the salt type. Out of the 23 organics investigated, the SRH of 20 organics followed the trend: (NH4)2SO4 ? NH4HSO4 ? NaCl ? NH4NO3. This trend is consistent with previous salting-out studies and the Hofmeister series. Based on the range of O:C values found in the atmosphere and the current results, liquid-liquid phase separation is likely a frequent occurrence in both marine and non-marine environments.

You, Y.; Renbaum-Wolff, L.; Bertram, A. K.

2013-07-01

330

Buffer-gas cooling of diatomic molecules  

NASA Astrophysics Data System (ADS)

Development of novel methods of molecular cooling and progress towards a general technique for molecular trapping are reported. Buffer-gas cooling of laser-ablated molecules is used to produce 1012 molecules of lead monoxide PbO in the ground X1Sigma(v? = 0) state at 4 K, opening a possibility for improved sensitivity of searches for the electric dipole moment of the electron. A new method of loading atoms and molecules into a buffer gas cell is developed, and is used to produce 1012 Rb atoms at 4.5 K and 1012 molecules of imidogen NH X3Sigma-(v? = 0) at <6 K. A next-generation trapping apparatus combining a molecular-beam loaded buffer gas cell with an in-vacuum 4.5-Tesla magnetic trap is developed. A critical parameter in buffer-gas-based magnetic trapping, the Zeeman relaxation rate in molecule-helium collisions, is measured for collisions of calcium monofluoride CaF with He. Up to 5 x 10 13 CaF X2Sigma+(v? = 0) molecules are produced via laser ablation at temperature of 2 K in helium buffer gas; the Zeeman relaxation rate is found to be 7.7 x 10 -15 cm3s-1. The result is consistent with a recent theoretical prediction, which indicates that the theory may be successfully used to predict suitability of molecular candidates for buffer-gas based trapping experiments and supports the continued use of new theoretical approaches to the calculation of molecular collisional processes.

Egorov, Dimitri Michael

331

Flexible and Adaptable Buffer Management Techniques for Database Management Systems  

Microsoft Academic Search

The problem of buffer management in database management systems is concerned with theefficient main memory allocation and management for answering database queries. Previous workson buffer allocation are based either exclusively on the availability of buffers at runtime or on theaccess patterns of queries. In this paper, we first propose a unified approach for buffer allocation inwhich both of these considerations

Christos Faloutsos; Raymond T. Ng; Timos K. Sellis

1995-01-01

332

Role of the venous system in hemodynamics during ultrafiltration and bicarbonate dialysis  

Microsoft Academic Search

Role of the venous system in hemodynamics during ultrafiltration and bicarbonate dialysis. A reduced venous compliance (VC) and inadequate venoconstriction may impair hemodynamics during hemodialysis, the first by impairing plasma volume preservation and by inducing a steep fall in central venous pressure (CVP) during minor plasma volume loss, the second by inadequate mobilization of hemodynamically inactive blood volume. For the

Jeroen P Kooman; Ulrich Gladziwa; Georg Böcker; Luc MAB van Bortel; Johannes P van Hooff; Karel ML Leunissen

1992-01-01

333

Stress Corrosion Cracking Characteristics of a Range of Pipeline Steels in Carbonate-Bicarbonate Solution  

Microsoft Academic Search

Stress corrosion cracking (SCC) characteristics of a range of pipeline steels immersed in a carbonate-bicarbonate solution were studied in terms of the deleterious effects of small-amplitude cyclic loading on threshold stress, together with the increase of crack nucleation and the decrease of average crack growth rates with increasing test times. Data were reported on conditions for coalescence or otherwise of

R. N. Parkins; W. K. Blanchard Jr; E. N. Belhimer

1993-01-01

334

Flotation of sodium carbonate and sodium bicarbonate salts from their saturated brines  

Microsoft Academic Search

The flotation behavior of sodium carbonates and sodium bicarbonate has been studied with dodecyl amine hydrochloride (DAH) and sodium dodecyl sulfate (SDS) as part of a research program to evaluate the potential of flotation technology for use in the trona industry. Laboratory microflotation experiments generally show that flotation of sodium carbonate salts is possible at least to some extent with

O Ozcan; J. D Miller

2002-01-01

335

Effect of Prepartum Energy, Body Condition, and Sodium Bicarbonate on Production of Cows in Early Lactation  

Microsoft Academic Search

In trial 1, the effects of dietary energy (102, 131 or 162% of requirement) in the dry period and of sodium bicarbonate (0 or .75% of diet dry matter) in early lactation were assessed with 31 cows in a 3 × 2 factorial arrangement of treatments. Body condition and weight increased linearly with prepartum energy. Dry matter intake and milk

Y. Boisclair; D. G. Grieve; J. B. Stone; O. B. Allen; G. K. Macleod

1986-01-01

336

Experimental Tricyclic Antidepressant Toxicity: A Randomized, Controlled Comparison of Hypertonic Saline Solution, Sodium Bicarbonate, and Hyperventilation  

Microsoft Academic Search

Study objective: We sought to compare the effects of hypertonic sodium chloride solution (HTS), sodium bicarbonate solution, and hyperventilation (HV) on severe tricyclic antidepressant (TCA) toxicity in a swine model. Methods: Twenty-four mixed-breed, domestic swine of either sex were given an intravenous infusion of nortriptyline (NT) until development of both a QRS duration longer than 120 ms and a systolic

James L McCabe; Daniel J Cobaugh; James J Menegazzi; John Fata

1998-01-01

337

Adding Sodium Bicarbonate to Lidocaine Enhances the Depth of Epidural Blockade  

Microsoft Academic Search

It is controversial whether adding CO, or sodium bicar- bonate to local anesthetics enhances the depth of epi- dural blockade. Repeated electrical stimulation is a re- liable test for assessing epidural analgesia and evokes temporal summation. We used this test to investigate the analgesic effect of lidocaine, with or without CO, or bicarbonate. Twenty-four patients undergoing epi- dural blockade with

Michele Curatolo; Steen Petersen-Felix; Lars Arendt-Nielsen; Rolf Lauber; Henrik Hogstrom; Pasquale Scaramozzino; Martin Luginbiihl; Thomas J. Sieber; Alex M. Zbinden

1998-01-01

338

Precipitating sandy aluminium hydroxide from sodium aluminate solution by the neutralization of sodium bicarbonate  

Microsoft Academic Search

In the sinter process for alumina production, it is still difficult to produce sandy aluminium hydroxide by the carbonation of sodium aluminate solution. Therefore, a precisely controllable and feasible process for the precipitation of sandy aluminium hydroxide from the supersaturated sodium aluminate solution neutralized by sodium bicarbonate aqueous solution is proposed for the first time, in which the neutralization reagent

Yan Li; Yifei Zhang; Chao Yang; Yi Zhang

2009-01-01

339

Synergistic effect of calcium and bicarbonate in enhancing arsenate release from ferrihydrite  

NASA Astrophysics Data System (ADS)

Many groundwater systems contain anomalously high arsenic concentrations, associated with less than expected retention of As by adsorption to iron (hydr)oxides. Although carbonates are ubiquitous in aquifers, their relationship to arsenate mobilization is not well characterized. This research examines arsenate release from poorly crystalline iron hydroxides in abiotic systems containing calcium and magnesium with bicarbonate under conditions of static and dynamic flow (pH 7.5-8). Aqueous arsenic levels remained low when arsenate-bearing ferrihydrite was equilibrated with artificial groundwater solution containing Ca, Mg, and HCO 3-. In batch titrations in which a solution of Ca and HCO 3- was added repeatedly, the ferrihydrite surface became saturated with adsorbed Ca and HCO 3-, and aqueous As levels increased by 1-2 orders of magnitude. In columns containing Ca or Mg and HCO 3-, As solubility initially mimicked titrations, but then rapidly increased by an additional order of magnitude (reaching 12 ?M As). Separately, calcium chloride and other simple salts did not induce As release, although sodium bicarbonate and lactate facilitated minor As release under flow. Results indicate that adsorption of calcium or magnesium with bicarbonate leads to As desorption from ferrihydrite, to a degree greater than expected from competitive effects alone, especially under dynamic flow. This desorption may be an important mechanism of As mobilization in As-impacted, circumneutral aquifers, especially those undergoing rapid mineralization of organic matter, which induces calcite dissolution and the production of dissolved calcium and bicarbonate.

Saalfield, Samantha L.; Bostick, Benjamin C.

2010-09-01

340

Crack Cocaine-Induced Cardiac Conduction Abnormalities Are Reversed by Sodium Bicarbonate Infusion  

PubMed Central

We report a dramatic case of a 19-year-old man with crack cocaine overdose with important clinical complications as cardiac arrest due to ventricular fibrillation and epileptics status. During this intoxication, electrocardiographic abnormalities similar to those found in tricyclic antidepressant poisoning were observed, and they were reversed by intravenous sodium bicarbonate infusion.

Miranda, Carlos Henrique; Pazin-Filho, Antonio

2013-01-01

341

Combating inadequate anesthesia in periapical infections, with sodium bicarbonate: a clinical double blind study.  

PubMed

INTRODUCTION: Local anesthetics are generally much less effective when administered in inflamed tissues. PURPOSE: This study was conducted to validate the addition of sodium bicarbonate in local anesthetics to increase its effectiveness as local infiltrations in teeth associated with periapical infections. METHODS: Two hundred subjects requiring extraction of maxillary teeth with periapical infections were enrolled. These subjects were divided in two groups of 100 subjects each. One group received local infiltration with 2 % lignocaine and 1:80,000 adrenaline, and the other group received local infiltration with sodium bicarbonate as an adjunct to the above mentioned local anesthetic solution. All extractions were performed using a consistent intra-alveolar technique by a single operator. Both the patient and the operator were blinded to the contents of local anesthetic solution. Data related to the onset of action of local anesthesia, pain experienced by the patient while undergoing extraction on two scales-"the visual analog scale and the verbal response scale", and any requirement of repeated injections during the procedure was recorded. RESULTS: Clinical and statistical data confirmed that the addition of sodium bicarbonate in local anesthetics did increase the efficacy of local anesthesia in inflamed tissues. CONCLUSION: It has been observed in this study that the action of sodium bicarbonate in local anesthetics increases the pH levels of these solutions, thus possibly making them more effective in an acidic environment. PMID:23740399

Gupta, Savina; Mandlik, Geetanjali; Padhye, Mukul N; Kini, Yogesh K; Kakkar, Shruti; Hire, Abhinav Vijay

2013-06-01

342

Crack cocaine-induced cardiac conduction abnormalities are reversed by sodium bicarbonate infusion.  

PubMed

We report a dramatic case of a 19-year-old man with crack cocaine overdose with important clinical complications as cardiac arrest due to ventricular fibrillation and epileptics status. During this intoxication, electrocardiographic abnormalities similar to those found in tricyclic antidepressant poisoning were observed, and they were reversed by intravenous sodium bicarbonate infusion. PMID:23762070

Miranda, Carlos Henrique; Pazin-Filho, Antônio

2013-01-01

343

Sodium bicarbonate improves the chance of resuscitation after 10 minutes of cardiac arrest in dogs  

Microsoft Academic Search

The likelihood of successful defibrillation and resuscitation decreases as the duration of cardiac arrest increases. Prolonged cardiac arrest is also associated with the development of acidosis. These experiments were designed to determine whether administration of sodium bicarbonate and\\/or adrenaline in combination with a brief period of cardiopulmonary resuscitation (CPR) prior to defibrillation would improve the outcome of prolonged cardiac arrest

Elaine C. M. Leong; Jason C. Bendall; Anita C. Boyd; Rosemarie Einstein

2001-01-01

344

Sodium bicarbonate supplementation prevents skilled tennis performance decline after a simulated match.  

PubMed

The supplementation of sodium bicarbonate (NaHCO3) could increase performance or delay fatigue in intermittent high-intensity exercise. Prolonged tennis matches result in fatigue, which impairs skilled performance. The aim of this study was to investigate the effect of NaHCO3 supplementation on skilled tennis performance after a simulated match. Nine male college tennis players were recruited for this randomized cross-over, placebo-controlled, double-blind study. The participants consumed NaHCO3 (0.3 g. kg-1) or NaCl (0.209 g. kg-1) before the trial. An additional supplementation of 0.1 g. kg-1 NaHCO3 or 0.07 g. kg-1 NaCl was ingested after the third game in the simulated match. The Loughborough Tennis Skill Test was performed before and after the simulated match. Post-match [HCO3-] and base excess were significantly higher in the bicarbonate trial than those in the placebo trial. Blood [lactate] was significantly increased in the placebo (pre: 1.22 ± 0.54; post: 2.17 ± 1.46 mM) and bicarbonate (pre: 1.23 ± 0.41; post: 3.21 ± 1.89 mM) trials. The match-induced change in blood [lactate] was significantly higher in the bicarbonate trial. Blood pH remained unchanged in the placebo trial (pre: 7.37 ± 0.32; post: 7.37 ± 0.14) but was significantly increased in the bicarbonate trial (pre: 7.37 ± 0.26; post: 7.45 ± 0.63), indicating a more alkaline environment. The service and forehand ground stroke consistency scores were declined significantly after the simulated match in the placebo trial, while they were maintained in the bicarbonate trial. The match-induced declines in the consistency scores were significantly larger in the placebo trial than those in the bicarbonate trial. This study suggested that NaHCO3 supplementation could prevent the decline in skilled tennis performance after a simulated match. PMID:20977701

Wu, Ching-Lin; Shih, Mu-Chin; Yang, Chia-Cheng; Huang, Ming-Hsiang; Chang, Chen-Kang

2010-01-01

345

Long-term oral sodium bicarbonate supplementation does not improve serum albumin levels in hemodialysis patients.  

PubMed

Metabolic acidosis, a frequent event in hemodialysis patients, has been implicated as a potential cause of protein-energy malnutrition. Unfortunately, correction of metabolic acidosis by means of high bicarbonate concentration in the dialysate does not seem to lead to significant changes in nutritional parameters. The project was a single-arm, open-label, 12-month pilot study at a university-based tertiary care center aimed at evaluating whether correction of metabolic acidosis through long-term oral sodium bicarbonate supplementation improves serum albumin levels and other nutritional parameters in patients undergoing maintenance hemodialysis. Twenty highly acidotic hemodialysis patients patients were invited to consume an oral supplementation of sodium bicarbonate (1 g, thrice daily), for 12 months. Patients were followed at baseline and every month, until month 12. At each follow-up visit, dry body weight, BMI, blood pressure, presence of edema, venous bicarbonate, and serum albumin were measured. Total lymphocyte count, fasting total cholesterol and C-reactive protein were assessed every 2 months. At baseline and at 12 months, the subjective global assessment of nutritional status and the protein equivalent of nitrogen appearance normalized to actual body weight were determined. Plasma bicarbonate level rose from 18.1 +/- 2.7 to 22.1 +/- 4.5 mmol/l after 10 months (p = 0.001). Mean serum albumin levels were 3.8 +/- 0.2 mg/dl at baseline and 3.9 +/- 0.2 at the end of the study. Repeated measure ANOVA showed that there was no significant effect of bicarbonate treatment on serum albumin levels (p = 0.29), dry weight (p = 0.1), serum total cholesterol (p = 0.97), total lymphocyte count (p = 0.69), or C-reactive protein (p = 0.85). Mean subjective global assessment score was 4.53 +/- 0.37 at baseline and 4.58 +/- 0.54 at 12 months (p = 0.1). Mean nPNA (g/kg/day) was 0.86 +/- 0.05 at baseline and 0.85 +/- 0.08 at month 12. The present study demonstrates that long-term oral sodium bicarbonate at the dose of 1 gram thrice daily has no significant effect on nutritional status of HD patients. PMID:17409769

Bossola, Maurizio; Giungi, Stefania; Tazza, Luigi; Luciani, Giovanna

2007-01-01

346

Sodium bicarbonate supplementation prevents skilled tennis performance decline after a simulated match  

PubMed Central

The supplementation of sodium bicarbonate (NaHCO3) could increase performance or delay fatigue in intermittent high-intensity exercise. Prolonged tennis matches result in fatigue, which impairs skilled performance. The aim of this study was to investigate the effect of NaHCO3 supplementation on skilled tennis performance after a simulated match. Nine male college tennis players were recruited for this randomized cross-over, placebo-controlled, double-blind study. The participants consumed NaHCO3 (0.3 g. kg-1) or NaCl (0.209 g. kg-1) before the trial. An additional supplementation of 0.1 g. kg-1 NaHCO3 or 0.07 g. kg-1 NaCl was ingested after the third game in the simulated match. The Loughborough Tennis Skill Test was performed before and after the simulated match. Post-match [HCO3-] and base excess were significantly higher in the bicarbonate trial than those in the placebo trial. Blood [lactate] was significantly increased in the placebo (pre: 1.22 ± 0.54; post: 2.17 ± 1.46 mM) and bicarbonate (pre: 1.23 ± 0.41; post: 3.21 ± 1.89 mM) trials. The match-induced change in blood [lactate] was significantly higher in the bicarbonate trial. Blood pH remained unchanged in the placebo trial (pre: 7.37 ± 0.32; post: 7.37 ± 0.14) but was significantly increased in the bicarbonate trial (pre: 7.37 ± 0.26; post: 7.45 ± 0.63), indicating a more alkaline environment. The service and forehand ground stroke consistency scores were declined significantly after the simulated match in the placebo trial, while they were maintained in the bicarbonate trial. The match-induced declines in the consistency scores were significantly larger in the placebo trial than those in the bicarbonate trial. This study suggested that NaHCO3 supplementation could prevent the decline in skilled tennis performance after a simulated match.

2010-01-01

347

High-performance multiqueue buffers for VLSI communication switches  

Microsoft Academic Search

A type of buffer called a dynamically allocated multiqueue (DAMQ) buffer, designed for use in n×n switches, is presented. This buffer provides efficient handling of variable-length packets and the forwarding of packets in non-FIFO (first-in-first-out) order. The microarchitecture of the DAMQ buffer and its controller is described in the context of the ComCoBB communication coprocessor for multicomputers. The DAMQ buffer

Y. Tamir; Gregory L. Frazier

1988-01-01

348

Performance Analysis of Buffering Schemes on Wormhole Routers  

Microsoft Academic Search

Wormhole switched input-buffered and middle-buffered routers with virtual channels are analyzed in this paper. Middle buffering refers to the placement of virtual channels between the demultiplexers and multiplexers of a crossbar switch. An analytical model for multistage interconnection networks using middle-buffered switches is developed. In addition, extensive simulation is conducted to assess the performance of the two buffering techniques in

Younes M. Boura; Chita R. Das

1997-01-01

349

Oxidation of ammonium sulfite in aqueous solutions using ozone technology  

NASA Astrophysics Data System (ADS)

How to deal with unstable ammonium sulfite, the byproduct of flue gas desulfuration by ammonia absorption methods, has been a difficult problem in recent years. Oxidation of ammonium sulfite in aqueous solutions using ozone produced by a surface discharge system was investigated in the paper. The oxidation efficiency of ammonium sulfite by ozone and traditional air aeration were compared, and the factors including ozone concentration, gas flow rate, initial concentration of ammonium sulfite solution and reaction temperature were discussed. The results show that the oxidation efficiency of ammonium sulfite by ozone technology reached nearly 100% under the optimum conditions, which had a significant increase compared with that by air aeration.

Li, Yue; Shang, Kefeng; Lu, Na; Li, Jie; Wu, Yan

2013-03-01

350

Bis(tri-ethyl-ammonium) chloranilate  

PubMed Central

In the crystal structure of the title compound [systematic name: bis­(tri­ethyl­ammonium) 2,5-di­chloro-3,6-dioxo­cyclo­hexa-1,4-diene-1,4-diolate], 2C6H16N+·C6Cl2O4 2?, the chloranilate anion lies on an inversion center. The tri­ethyl­ammonium cations are linked on both sides of the anion via bifurcated N—H?(O,O) and weak C—H?O hydrogen bonds to give a centrosymmetric 2:1 aggregate. The 2:1 aggregates are further linked by C—H?O hydrogen bonds into a zigzag chain running along [01-1].

Gotoh, Kazuma; Maruyama, Shinpei; Ishida, Hiroyuki

2013-01-01

351

High Pressure NMR Study of Ammonium Thiocyanate  

NASA Astrophysics Data System (ADS)

Wide-line proton NMR spectra of ammonium thiocyanate have been recorded at 77 K as a function of external hydrostatic pressure. Contrary to expectations the line-width and the second moment decrease with the increase of pressure. This, however, is in accordance with the anomalous behaviour observed in other magnetic resonance studies of this compound and can be understood in terms of the change of electron density around the nitrogen atom of the SCN- group.

Ramanathan, K. V.

1993-06-01

352

Decyl-ammonium octa-noate  

PubMed Central

The title compound, C10H24N+·C8H15O2 ?, forms a layered structure in which inter­molecular N+—H?O hydrogen bonds connect anions and cations, forming a two-dimensional network parallel to (010). The n-alkyl chains of the decyl­ammonium cations pack according to an ortho­rhom­bic ‘subcell’ with approximate dimensions 5.1 × 7.3?Å, and they are significantly distorted from planarity.

Jefferson, Andrew E.; Sun, Chenguang; Bond, Andrew D.; Clarke, Stuart M.

2011-01-01

353

Corrosion and repairs of ammonium carbamate decomposers  

SciTech Connect

Corrosion-erosion problems occurred in the carbon steel base metal of the ammonium carbamate decomposers in an urea extraction process lined with type 316L (UNS S31603) urea grade stainless steel. The cladding was replaced by weld overlay using a semiautomatic gas metal arc welding process. The first layer was alloy 25%Cr-15%Ni-2%Mo (UNS W30923); the second layer was alloy 25%Cr-22%Ni-2%Mo (UNS W31020).

De Romero, M.F.; Galban, J.P. [Pequivan S.A., Maracaibo (Venezuela)

1996-05-01

354

Bicarbonate can improve the prognostic value of the MELD score for critically ill patients with cirrhosis.  

PubMed

Abstract The prognosis of critically ill patients with cirrhosis is poor. Our aim was to identify an objective variable that can improve the prognostic value of the Model of End-Stage Liver Disease (MELD) score in patients who have cirrhosis and are admitted to the intensive care unit (ICU). This retrospective cohort study included 177 patients who had liver cirrhosis and were admitted to the ICU. Data pertaining to arterial blood gas-related parameters and other variables were obtained on the day of ICU admission. The overall ICU mortality rate was 36.2%. The bicarbonate (HCO3) level was found to be an independent predictor of ICU mortality (odds ratio, 2.3; 95% confidence interval [CI], 1.0-4.8; p?=?0.038). A new equation was constructed (MELD-Bicarbonate) by replacing total bilirubin by HCO3 in the original MELD score. The area under the receiver operating characteristic curve for predicting ICU mortality was 0.76 (95% CI, 0.69-0.84) for the MELD-Bicarbonate equation, 0.73 (95% CI, 0.65-0.81) for the MELD score, and 0.71 (95% CI, 0.63-0.80) for the Acute Physiology and Chronic Health Evaluation II score. Bicarbonate level assessment, as an objective and reproducible laboratory test, has significant predictive value in critically ill patients with cirrhosis. In contrast, the predictive value of total bilirubin is not as prominent in this setting. The MELD-Bicarbonate equation, which included three variables (international normalized ratio, creatinine level, and HCO3 level), showed better prognostic value than the original MELD score in critically ill patients with cirrhosis. PMID:24601755

Chen, Cheng-Yi; Pan, Chi-Feng; Wu, Chih-Jen; Chen, Han-Hsiang; Chen, Yu-Wei

2014-07-01

355

Sodium bicarbonate-based hydration prevents contrast-induced nephropathy: a meta-analysis  

PubMed Central

Background Contrast-induced nephropathy is the leading cause of in-hospital acute renal failure. This side effect of contrast agents leads to increased morbidity, mortality, and health costs. Ensuring adequate hydration prior to contrast exposure is highly effective at preventing this complication, although the optimal hydration strategy to prevent contrast-induced nephropathy still remains an unresolved issue. Former meta-analyses and several recent studies have shown conflicting results regarding the protective effect of sodium bicarbonate. The objective of this study was to assess the effectiveness of normal saline versus sodium bicarbonate for prevention of contrast-induced nephropathy. Methods The study searched MEDLINE, EMBASE, Cochrane databases, International Pharmaceutical Abstracts database, ISI Web of Science (until 15 December 2008), and conference proceedings for randomized controlled trials that compared normal saline with sodium bicarbonate-based hydration regimen regarding contrast-induced nephropathy. Random-effects models were used to calculate summary odds ratios. Results A total of 17 trials including 2,633 subjects were pooled. Pre-procedural hydration with sodium bicarbonate was associated with a significant decrease in the rate of contrast-induced nephropathy (odds ratios 0.52; 95% confidence interval 0.34–0.80, P = 0.003). Number needed to treat to prevent one case of contrast-induced nephropathy was 16 (95% confidence interval 10–34). No significant differences in the rates of post-procedure hemodialysis (P = 0.20) or death (P = 0.53) was observed. Conclusion Sodium bicarbonate-based hydration was found to be superior to normal saline in prevention of contrast-induced nephropathy in this updated meta-analysis.

Meier, Pascal; Ko, Dennis T; Tamura, Akira; Tamhane, Umesh; Gurm, Hitinder S

2009-01-01

356

Effect of prolonged bicarbonate administration on plasma potassium in terminal renal failure.  

PubMed

In hemodialysis patients with hyperkalemia, i.v. sodium bicarbonate has recently been found to be ineffective in lowering plasma potassium within one hour. In the present study the effect of a prolonged bicarbonate infusion on plasma potassium was investigated. Twelve patients with terminal renal failure who were on hemodialysis were infused i.v. with 8.4% sodium bicarbonate (4 mmol/min) for one hour and with 1.4% (0.5 mmol/min) for five hours (total amount 390 mmol). Plasma bicarbonate rose from 17.5 at baseline to 28.4 and 29.6 mmol/liter, and blood pH from 7.32 to 7.46 and 7.48 at one and six hours, respectively. Plasma potassium did not change significantly after one and two hours (6.04 at baseline, 5.91 and 5.77 mmol/liter, respectively). Only at four and six hours did a moderate decline to 5.44 (P less than 0.05) and to 5.30 (P less than 0.01) occur, of which approximately half was calculated to be due to ECF volume expansion. However, no change or a very moderate decrease was observed in three patients even after six hours (+0.19, -0.32, -0.33 mmol/liter). Five patients with higher baseline plasma potassium (6.15 to 8.15 mmol/liter) behaved like seven with lower levels (5.25 to 5.87 mmol/liter). Tented T-waves in the ECG of seven patients disappeared after one hour only in one patient. Plasma aldosterone, norepinephrine and epinephrine were normal to elevated before and tended to fall during i.v. bicarbonate. Plasma dopamine and insulin were in the normal range.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1552710

Blumberg, A; Weidmann, P; Ferrari, P

1992-02-01

357

Equation of State of Ammonium Nitrate  

NASA Astrophysics Data System (ADS)

Ammonium nitrate (AN) is a widely used fertilizer and mining explosive. AN is commonly used in ammonium nitrate-fuel oil (ANFO), which is a mixture of explosive-grade AN prills and fuel oil in a 94:6 ratio by weight. ANFO is a non-ideal explosive with measured detonation velocities around 4 km/s. The equation of state properties and known initiation behavior of neat AN are limited. We present the results of a series of gas gun-driven plate impact experiments on pressed neat ammonium nitrate at 1.72 g/cm3. No evidence of initiation was observed under shock loading to 22 GPa. High pressure x-ray diffraction experiments in diamond anvil cells provided insight into the high pressure phase behavior over the same pressure range (to 25 GPa), as well as a static isotherm at ambient temperature. From the isotherm and thermodynamic properties at ambient conditions, a preliminary unreacted equation of state (EOS) has been developed based on the Murnaghan isotherm and Helmholtz formalism [1], which compares favorably with the available experimental Hugoniot data on several densities of AN.

Robbins, David L.; Sheffield, Stephen A.; Dattelbaum, Dana M.; Velisavljevic, Nenad; Stahl, David B.

2009-12-01

358

Detection of the Ammonium Ion in Space  

NASA Astrophysics Data System (ADS)

We report on the detection of a narrow feature at 262816.73 MHz toward Orion and the cold prestellar core B1-bS which we attribute to the 10-00 line of the deuterated ammonium ion, NH3D+. The observations were performed with the IRAM 30 m radio telescope. The carrier has to be a light molecular species as it is the only feature detected over 3.6 GHz of bandwidth. The hyperfine structure is not resolved, indicating a very low value for the electric quadrupolar coupling constant of nitrogen which is expected for NH3D+ as the electric field over the N nucleus is practically zero. Moreover, the feature is right at the predicted frequency for the 10-00 transition of the ammonium ion, 262817 ± 6 MHz (3?), using rotational constants derived from new infrared data obtained in our laboratory in Madrid. The estimated column density is (1.1 ± 0.2) × 1012 cm-2. Assuming a deuterium enhancement similar to that of NH2D, we derive N(NH_4^+) ~= 2.6 × 1013 cm-2, i.e., an abundance for ammonium of a few 10-11. This work was based on observations carried out with the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain)

Cernicharo, J.; Tercero, B.; Fuente, A.; Domenech, J. L.; Cueto, M.; Carrasco, E.; Herrero, V. J.; Tanarro, I.; Marcelino, N.; Roueff, E.; Gerin, M.; Pearson, J.

2013-07-01

359

Queueing analysis of finite buffer token networks  

Microsoft Academic Search

This paper introduces analytic models for evaluating demand assignment protocols in realistic finite buffer\\/finite station network configurations. We present a solution for implicit and explicit token passing systems enabling us to model local area networks, such as Token Bus. We provide, for the first time, a tractable approximate solution by using an approach based on restricted occupancy urn models. The

Aura Ganz; Imrich Chlamtac

1988-01-01

360

Buffered DDA command generation in a CNC  

Microsoft Academic Search

In a computerized numerical controller (CNC), interpolating more than one block in a sampling interval, increases the feed rate. Some commands skipped by the generator are pre-saved in a circular buffer, to provide faster operation than that of a conventional digital differential analyzer. The feed rate can be increased when programmed distances are short. The high feed rate is confirmed

Yih-Fang Chang

2003-01-01

361

Antibody buffering of a ligand in vivo  

NASA Astrophysics Data System (ADS)

Clearance is the practical limit on drug action. Here we propose a means of slowing clearance, thereby extending drug lifetime in vivo by "antibody buffering." In this process, a drug and an anti-drug antibody are coadministered. Most of the drug is bound to the antibody, preventing the drug from acting, but also preventing its elimination. A dynamic free drug pool is established by reversible dissociation from the antibody. The free drug is active and can be eliminated, but the free pool is constantly replenished by reequilibration from the antibody-drug complex, giving a long effective lifetime. Here we explore antibody buffering experimentally by using a model compound, 2-phenyloxazol-5-one--aminobutyrate (Ox), as a drug proxy. We show that antibody buffering can extend by an order of magnitude the plasma lifetime of Ox in rats, and that the steady-state Ox level depends on the molecular properties of the antibody used to buffer the Ox. In addition, the anti-Ox antibody can be recharged with drug in vivo to extend Ox lifetime without additional antibody administration, making this technique even more suitable for possible clinical application. drug delivery | pharmacokinetics | immunotherapy | antibody-antigen interactions

O'Hear, Carol E.; Foote, Jefferson

2005-01-01

362

Stochastic analysis of moisture buffering in rooms  

Microsoft Academic Search

SUMMARY: This paper presents a stochastic method to obtain design values for the necessary moisture buffering of wall materials in order to prevent moisture damage. The difference in maximal and minimal relative humidity in the room during a day is chosen as an indicator for the moisture damage risk. Choosing an acceptable probability of occurrence of moisture damage allows then

Jan Carmeliet; Dominique Derome

363

Buffer layers on biaxially textured metal substrates  

DOEpatents

A method is disclosed for forming a biaxially textured buffer layer on a biaxially oriented metal substrate by using a sol-gel coating technique followed by pyrolyzing/annealing in a reducing atmosphere. This method is advantageous for providing substrates for depositing electronically active materials thereon.

Shoup, Shara S. (Woodstock, GA); Paranthamam, Mariappan (Knoxville, TN); Beach, David B. (Knoxville, TN); Kroeger, Donald M. (Knoxville, TN); Goyal, Amit (Knoxville, TN)

2001-01-01

364

Delay Reduction Techniques for Playout Buffering  

Microsoft Academic Search

Receiver synchronization of continuous mediastreams is required to deal with delay differences and variationsresulting from delivery over packet networks suchas the Internet. This function is commonly provided usingper-stream playout buffers which introduce additionaldelay in order to produce a playout schedule which meetsthe synchronization requirements. Packets which arrive aftertheir scheduled playout time are considered late and arediscarded. In this paper, we

Cormac J. Sreenan; Jyh-cheng Chen; Prathima Agrawal; B. Narendran

2000-01-01

365

A new view-buffer splatting algorithm  

Microsoft Academic Search

Splatting is an important object-order direct volume rendering algorithm which projects each voxel onto the view plane and composite it into a accumulating image by using a preintegrated interpolation kernels called footprint. Popular sheet-buffer based splatting algorithms overcome most problems at the cost of leading to popping artifacts. In this paper we present a new splatting volume rendering method which

Zhigang Sun; Jiawan Zhang; Jizhou Sun; Zunce Wei

2003-01-01

366

Acclimation and toxicity of high ammonium concentrations to unicellular algae.  

PubMed

A literature review on the effects of high ammonium concentrations on the growth of 6 classes of microalgae suggests the following rankings. Mean optimal ammonium concentrations were 7600, 2500, 1400, 340, 260, 100 ?M for Chlorophyceae, Cyanophyceae, Prymnesiophyceae, Diatomophyceae, Raphidophyceae, and Dinophyceae respectively and their tolerance to high toxic ammonium levels was 39,000, 13,000, 2300, 3600, 2500, 1200 ?M respectively. Field ammonium concentrations <100 ?M would not likely reduce the growth rate of most microalgae. Chlorophytes were significantly more tolerant to high ammonium than diatoms, prymnesiophytes, dinoflagellates, and raphidophytes. Cyanophytes were significantly more tolerant than dinoflagellates which were the least tolerant. A smaller but more complete data set was used to estimate ammonium EC?? values, and the ranking was: Chlorophyceae>Cyanophyceae, Dinophyceae, Diatomophyceae, and Raphidophyceae. Ammonia toxicity is mainly attributed to NH? at pHs >9 and at pHs <8, toxicity is likely associated with the ammonium ion rather than ammonia. PMID:24533997

Collos, Yves; Harrison, Paul J

2014-03-15

367

Role of the buffer solution in the chemical deposition of CdS films for CIGS solar cell applications  

NASA Astrophysics Data System (ADS)

In this work, the effects of NH4Ac on the structural and the electro-optical properties of CdS films were investigated. CdS thin films were deposited on soda-lime glass and indium-tin-oxide (ITO) coated glass from a chemical bath containing 0.025 M cadmium acetate, 0 M ~ 0.2 M ammonium acetate, 0.5 M thiourea, and ammonia. Cadmium acetate was the cadmium source, ammonium acetate served as a buffer, ammonia was the complexing agent, and thiourea was the source of sulfur. A commonl- available chemical bath deposition system was successfully modified to obtain precise control over the pH of the solution at 75 °C during the deposition. Chemically deposited CdS films were studied by using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), optical transmittance, and electrical resistivity measurements.

Lee, Sooho; Kim, Donguk; Baek, Dohyun; Hong, Byoungyou; Yi, Junsin; Lee, Jaehyeong; Park, Yong Seob; Choi, Wonseok

2014-05-01

368

In situ continuous monitoring of chloride, nitrate and ammonium in a temporary stream Comparison with standard methods.  

PubMed

A multi-parameter probe was used for in situ chloride, nitrate and ammonium measurements in a temporary stream (Ribeira da Pardiela, in the South of Portugal). Comparison with standard analytical methods was performed for all elements. For chloride, the results of the probe depicted the same behaviour as that obtained with the standard method, although it is clear that the matrix effects were present. For nitrate, the results obtained with the probe were in agreement with the other standard methods used, except for samples collected during drought, when the stream water became brownish and exhaled an offensive smell, due to the decomposition of organic matter. For ammonium, surprisingly the probe show to be the best option, the phenate method being affected by matrix effects. The results still suggest an interference of the bicarbonate ion on nitrate determination, but standard additions approach was shown to minimize most of the matrix effects. Recoveries were reasonable to good for all the three anions under scrutiny. PMID:19071428

Capelo, S; Mira, F; de Bettencourt, A M

2007-02-28

369

COS Science Data Buffer Check/Self-Tests for CS Buffer RAM and DIB RAM  

NASA Astrophysics Data System (ADS)

The COS Science Buffer RAM is checked for bit flips during SAA passages. This is followed by a Control Section {CS} self-test consisting of writing/reading a specified bit pattern from each memory location in Buffer RAM and a similar test for DIB RAM. The DIB must be placed in BOOT mode for its self-test. The CS Buffer RAM self-test as well as the bit flip tests are all done with the CS in Operate. Supports Activity COS-03;

Welty, Alan

2008-07-01

370

Hydrothermally grown ZnO buffer layer for the growth of highly (4 wt%) Ga-doped ZnO epitaxial thin films on MgAl 2O 4 (1 1 1) substrates  

NASA Astrophysics Data System (ADS)

Gallium (4 wt%) doped ZnO (GZO) thin films were deposited on hydrothermally grown ZnO buffered and non-buffered MgAl 2O 4 (1 1 1) substrates by RF magnetron sputtering technique at a growth temperature of 250 °C. The epitaxial ZnO buffer layer was deposited on the MgAl 2O 4 (1 1 1) substrate by a hydrothermal technique using aqueous solutions of zinc nitrate hexahydrate, ammonium nitrate and ammonium hydroxide at 90 °C. The effect of the ZnO buffer layer on the crystallinity, epitaxial nature, surface morphology, optical and electrical properties of the GZO thin films is investigated. X-ray diffraction and transmission electron microscopy showed that the hydrothermally grown ZnO buffer layer and GZO thin film grown on the hydrothermally grown ZnO buffered substrate were grown epitaxially with an orientation relationship of (0 0 0 1)[?(1 1 1)[O4. However, the GZO thin films grown on the non-buffered substrate are polycrystalline in nature with a hexagonal wurtzite phase. The room temperature photoluminescence spectra of the GZO epitaxial thin films grown on the buffered substrate revealed a sharp near band edge emission peak and a lower broad deep-level emission peak compared to the polycrystalline GZO thin film grown on a non-buffered substrate. The electrical resistivity of the GZO thin films is found to be proved from 4.69×10 -3 to 2.27×10 -3 ? cm by introducing the hydrothermally grown ZnO buffer layer between the GZO thin film and MgAl 2O 4 (1 1 1) substrate.

Shin, Seung Wook; Kwon, Ye Bin; Moholkar, A. V.; Heo, Gi-Seok; Jung, In Ok; Moon, Jong-Ha; Kim, Jin Hyeok; Lee, Jeong Yong

2011-05-01

371

The effect of varying levels of sodium bicarbonate on polychlorinated biphenyl dechlorination in Hudson River sediment cultures.  

PubMed

The addition of different concentrations of sodium bicarbonate had a profound effect on 2,3,4,5-chlorobiphenyl (2,3,4,5-CB) dechlorination in Hudson River sediment cultures. The most extensive dechlorination was observed in cultures to which 100 mg l(-1) bicarbonate was added. Cultures amended with 1000 mg l(-1) bicarbonate had the least extensive dechlorination, with 2,4-CB and 2,5-CB as predominant end-products. A significant loss of total chlorinated biphenyl mass was observed in cultures to which < or = 500 mg l(-1) bicarbonate was added, suggesting that degradation beyond chlorinated biphenyls occurred. The dynamics of acetate formation were different among the treatments, with high acetate concentrations detected throughout the 303-day experiment in cultures to which 1000 mg l(-1) bicarbonate had been added. Sodium bicarbonate addition also had a significant impact on bacterial community structure as detected by polymerase chain reaction-denaturant gradient gel electrophoresis (PCR-DGGE) of 16S rRNA gene fragments. Three putative polychlorinated biphenyl (PCB) dechlorinators were identified; one Dehalococcoides-like population was detected in all enrichment cultures, whereas two Dehalobacter-like populations were only detected in the enrichment cultures with the most extensive dechlorination. These results suggest that the availability of bicarbonate, and potentially sodium, may affect PCB dechlorination in Hudson River sediment and thus need to be taken into consideration when assessing the fate of PCBs or implementing bioremediation. PMID:16817937

Yan, Tao; LaPara, Timothy M; Novak, Paige J

2006-07-01

372

The effect of varying levels of sodium bicarbonate on polychlorinated biphenyl dechlorination in Hudson River sediment cultures  

PubMed Central

Summary The addition of different concentrations of sodium bicarbonate had a profound effect on 2,3,4,5-chlorobiphenyl (2,3,4,5-CB) dechlorination in Hudson River sediment cultures. The most extensive dechlorination was observed in cultures to which 100 mg l?1 bicarbonate was added. Cultures amended with 1000 mg l?1 bicarbonate had the least extensive dechlorination, with 2,4-CB and 2,5-CB as predominant end-products. A significant loss of total chlorinated biphenyl mass was observed in cultures to which ?500 mg l?1 bicarbonate was added, suggesting that degradation beyond chlorinated biphenyls occurred. The dynamics of acetate formation were different among the treatments, with high acetate concentrations detected throughout the 303-day experiment in cultures to which 1000 mg l?1 bicarbonate had been added. Sodium bicarbonate addition also had a significant impact on bacterial community structure as detected by polymerase chain reaction-denaturant gradient gel electrophoresis (PCR-DGGE) of 16S rRNA gene fragments. Three putative polychlorinated biphenyl (PCB) dechlorinators were identified; one Dehalococcoides-like population was detected in all enrichment cultures, whereas two Dehalobacter-like populations were only detected in the enrichment cultures with the most extensive dechlorination. These results suggest that the availability of bicarbonate, and potentially sodium, may affect PCB dechlorination in Hudson River sediment and thus need to be taken into consideration when assessing the fate of PCBs or implementing bioremediation.

Yan, Tao; LaPara, Timothy M.; Novak, Paige J.

2007-01-01

373

Sodium Bicarbonate Treatment during Transient or Sustained Lactic Acidemia in Normoxic and Normotensive Rats  

PubMed Central

Introduction Lactic acidosis is a frequent cause of poor outcome in the intensive care settings. We set up an experimental model of lactic acid infusion in normoxic and normotensive rats to investigate the systemic effects of lactic acidemia per se without the confounding factor of an underlying organic cause of acidosis. Methodology Sprague Dawley rats underwent a primed endovenous infusion of L(+) lactic acid during general anesthesia. Normoxic and normotensive animals were then randomized to the following study groups (n?=?8 per group): S) sustained infusion of lactic acid, S+B) sustained infusion+sodium bicarbonate, T) transient infusion, T+B transient infusion+sodium bicarbonate. Hemodynamic, respiratory and acid-base parameters were measured over time. Lactate pharmacokinetics and muscle phosphofructokinase enzyme's activity were also measured. Principal Findings Following lactic acid infusion blood lactate rose (P<0.05), pH (P<0.05) and strong ion difference (P<0.05) drop. Some rats developed hemodynamic instability during the primed infusion of lactic acid. In the normoxic and normotensive animals bicarbonate treatment normalized pH during sustained infusion of lactic acid (from 7.22±0.02 to 7.36±0.04, P<0.05) while overshoot to alkalemic values when the infusion was transient (from 7.24±0.01 to 7.53±0.03, P<0.05). When acid load was interrupted bicarbonate infusion affected lactate wash-out kinetics (P<0.05) so that blood lactate was higher (2.9±1 mmol/l vs. 1.0±0.2, P<0.05, group T vs. T+B respectively). The activity of phosphofructokinase enzyme was correlated with blood pH (R2?=?0.475, P<0.05). Conclusions pH decreased with acid infusion and rose with bicarbonate administration but the effects of bicarbonate infusion on pH differed under a persistent or transient acid load. Alkalization affected the rate of lactate disposal during the transient acid load.

Valenza, Franco; Pizzocri, Marta; Salice, Valentina; Chevallard, Giorgio; Fossali, Tommaso; Coppola, Silvia; Froio, Sara; Polli, Federico; Gatti, Stefano; Fortunato, Francesco; Comi, Giacomo P.; Gattinoni, Luciano

2012-01-01

374

Coupled microrings data buffer using fast light  

NASA Astrophysics Data System (ADS)

We present a theoretical study of a trap-door optical buffer based on a coupled microrings add/drop filter (ADF) utilizing the white light cavity (WLC). The buffer "trap-door" can be opened and closed by tuning the resonances of the microrings comprising the ADF and trap/release optical pulses. We show that the WLC based ADF yields a maximally flat filter which exhibits superior performances in terms of bandwidth and flatness compared to previous design approaches. We also present a realistic, Silicon-over-Insulator based, design and performance analysis taking into consideration the realistic properties and limitations of the materials and the fabrication process, leading to delays exceeding 850ps for 80GHz bandwidth, and a corresponding delay-bandwidth product of approximately 70.

Scheuer, Jacob; Shahriar, Selim

2013-03-01

375

Spacecraft optical disk recorder memory buffer control  

NASA Astrophysics Data System (ADS)

This paper discusses the research completed under the NASA-ASEE summer faculty fellowship program. The project involves development of an Application Specific Integrated Circuit (ASIC) to be used as a Memory Buffer Controller (MBC) in the Spacecraft Optical Disk System (SODR). The SODR system has demanding capacity and data rate specifications requiring specialized electronics to meet processing demands. The system is being designed to support Gigabit transfer rates with Terabit storage capability. The complete SODR system is designed to exceed the capability of all existing mass storage systems today. The ASIC development for SODR consist of developing a 144 pin CMOS device to perform format conversion and data buffering. The final simulations of the MBC were completed during this summer's NASA-ASEE fellowship along with design preparations for fabrication to be performed by an ASIC manufacturer.

Hodson, Robert F.

1993-12-01

376

How Close Is Safe? Buffer Zone Development  

NSDL National Science Digital Library

The effects of volcanoes on both the environment and people are the focus of this investigation. Students are introduced to the term "buffer" and are tasked with creating a possible buffer zone around Mount St. Helens. Students begin by assigning 32 pre-written statements related to volcanoes into categories of cause, effect and human responses. The chart, along with true-color and false-color LandSat images from 1980 and 1999, are used to study the eruption of Mount St. Helens to determine that possible buffer zone. The URL opens to the investigation directory, with links to teacher and student materials, lesson extensions, resources, teaching tips, and assessment strategies. As the first investigation in this module entitled, "Volcanoes- Local Hazard, Global Issue," the teacher's guide will begin with a two-page module overview and list of all standards addressed. This is Investigation 1 of three found in the Grades 5-8 Module 1 of Mission Geography. The Mission Geography curriculum integrates data and images from NASA missions with the National Geography Standards. Each of the three investigations in Module 1, while related, can be done independently.

377

Estimating the buffer capacity of forest soils  

SciTech Connect

The organic-matter content of New England soils is an index of buffer capacity, and can be measured to indicate how forest soils might respond to acid precipitation. Buffer capacity, as defined herein, is the milliequivalents of H/sup +/ or OH/sup -/ that must be added to a kilogram of soil to change its pH by one unit. As such, it is an index of how soil pH will respond to H/sup +/ in acid precipitation. At four locations in New England, the buffer capacity of organic and mineral horizons for well-drained forest soils under second-growth forests and in new and regrowing clearcuts was measured. The sites included a spruce-fir forest in central Maine, two northern hardwood forests in northern New Hampshire, and a central hardwood forest in southern Connecticut. Soil materials were titrated by adding known amounts of HCl or NaOH and measuring the pH after 24 hours. Details on methods were given in this paper. 1 table.

Hornbeck, J.W.; Federer, C.A.

1985-11-01

378

Estimation of bottom ammonium affinity in the New Caledonia lagoon  

NASA Astrophysics Data System (ADS)

Ammonium affinity of New Caledonia lagoon benthic communities was measured during the course of 33 in situ enrichment experiments, in order to estimate the contribution of benthos to ammonium fluxes. Ammonium chloride was injected into enclosures pushed into the sediment, in order to obtain a concentration of 20 22 ?mol l-1 in the enclosed water which approximated the interstitial water content. Ammonium kinetic uptake was then followed for two hours. Grey-sand bottom displayed the highest affinity for ammonium, but white-sand and muddy bottom affinity was of the same order of magnitude. Macrophytes, and microphytes (when macrophytes are absent), account for the bulk of ammonium bottom uptake. As a result, grey-sand bottoms with their dense macrophyte cover represent a sink for water column nitrogen and play a key role in nutrient cycling of the lagoon.

Boucher, G.; Clavier, J.; Garrigue, C.

1994-01-01

379

Human BTR1, a new bicarbonate transporter superfamily member and human AE4 from kidney.  

PubMed

We report the cloning, characterization, and chromosomal localization of two novel human members of the bicarbonate transporter superfamily, BTR1 (Bicarbonate Transporter Related protein-1) and AE4 (Anion Exchange protein 4). BTR1 is a novel mammalian protein. The BTR1 gene maps to chromosome 20p12 and encodes a 100 kDa protein predominantly expressed in the kidney, salivary glands, testis, thyroid glands, and trachea. The AE4 gene maps to chromosome 5q23-31 and encodes a 104 kDa protein expressed mainly in the kidney. Human AE4 shares 84% identity with the recently reported rabbit AE4, a sodium independent, Cl(-)/HCO(-)(3) exchanger located on the apical membrane of beta-intercalated kidney cells. PMID:11302728

Parker, M D; Ourmozdi, E P; Tanner, M J

2001-04-20

380

Transformation of sodium bicarbonate and CO2 into sodium formate over NiPd nanoparticle catalyst.  

PubMed

The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability. PMID:24790945

Wang, Mengnan; Zhang, Jiaguang; Yan, Ning

2013-01-01

381

Sodium Bicarbonate Enhances the Severity of Infection in Neutropenic Mice Orally Inoculated with Listeria monocytogenes EGD  

PubMed Central

Epidemiological studies have suggested an association between antacid therapy and development of listeriosis in humans. In this study we used a neutropenic mouse model to demonstrate that oral administration of sodium bicarbonate shortly before intragastric (i.g.) inoculation with Listeria monocytogenes EGD (serotype 1/2a) significantly increased the severity of the resulting systemic infection. An explanation for this observation is provided by evidence that L. monocytogenes EGD is rapidly inactivated in synthetic gastric fluid at pH below 5. A second strain of L. monocytogenes (CM [serotype 1/2b]) exhibited little ability to cause systemic infection following i.g. inoculation and was not significantly enhanced by administration of sodium bicarbonate. Strain CM was readily inactivated in synthetic gastric fluid even at pH 7. These data suggest that gastric acidity and enzymes provide some innate defense against gastrointestinal listeriosis in neutropenic mice.

Czuprynski, C. J.; Faith, N. G.

2002-01-01

382

Transformation of sodium bicarbonate and CO2 into sodium formate over NiPd nanoparticle catalyst  

PubMed Central

The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability.

Wang, Mengnan; Zhang, Jiaguang; Yan, Ning

2013-01-01

383

META-ANALYSIS OF NITROGEN REMOVAL IN RIPARIAN BUFFERS  

EPA Science Inventory

Riparian buffer zones, the vegetated region adjacent to streams and wetlands, are thought to be effective at intercepting and controlling nitrogen loads entering water bodies. Riparian buffer width may be positively related to nitrogen removal effectiveness by influencing nitrog...

384

Multiphasic Buffer Systems. Instructions for Use of the Systems Catalogue.  

National Technical Information Service (NTIS)

The terminology of the 'Systems Catalogue' is explained. Instructions are given for the procedure by which a multiphasic buffer system, optimal for the particular application, can be identified by System Number for retrieval from the Multiphasic Buffer Sy...

T. M. Jovin M. L. Dante A. Chrambach

1970-01-01

385

Complexation of buffer constituents with neutral complexation agents: part I. Impact on common buffer properties.  

PubMed

The complexation of buffer constituents with the complexation agent present in the solution can very significantly influence the buffer properties, such as pH, ionic strength, or conductivity. These parameters are often crucial for selection of the separation conditions in capillary electrophoresis or high-pressure liquid chromatography (HPLC) and can significantly affect results of separation, particularly for capillary electrophoresis as shown in Part II of this paper series (Beneš, M.; Riesová, M.; Svobodová, J.; Tesa?ová, E.; Dubský, P.; Gaš, B. Anal. Chem. 2013, DOI: 10.1021/ac401381d). In this paper, the impact of complexation of buffer constituents with a neutral complexation agent is demonstrated theoretically as well as experimentally for the model buffer system composed of benzoic acid/LiOH or common buffers (e.g., CHES/LiOH, TAPS/LiOH, Tricine/LiOH, MOPS/LiOH, MES/LiOH, and acetic acid/LiOH). Cyclodextrins as common chiral selectors were used as model complexation agents. We were not only able to demonstrate substantial changes of pH but also to predict the general complexation characteristics of selected compounds. Because of the zwitterion character of the common buffer constituents, their charged forms complex stronger with cyclodextrins than the neutral ones do. This was fully proven by NMR measurements. Additionally complexation constants of both forms of selected compounds were determined by NMR and affinity capillary electrophoresis with a very good agreement of obtained values. These data were advantageously used for the theoretical descriptions of variations in pH, depending on the composition and concentration of the buffer. Theoretical predictions were shown to be a useful tool for deriving some general rules and laws for complexing systems. PMID:23889602

Riesová, Martina; Svobodová, Jana; Tošner, Zden?k; Beneš, Martin; Tesa?ová, Eva; Gaš, Bohuslav

2013-09-17

386

The buffering ability of commonly employed cardiopulmonary bypass solutions and alkalizing agents.  

PubMed

This experiment evaluated the hydrogen ion (H+) buffering capacity (BC) of solutions and alkalizing agents employed during cardiopulmonary bypass (CPB). A solution's BC can be determined when a known quantity of H+ is titrated into the solution and the change () in pH (-log of the hydrogen ion activity ([H+]a)) is measured ([H+]a/mmole H+). Eleven solutions were studied:Lactated Ringers (LR), 0.9% NaCl (NS), Plasma-Lyte A, Hespan (6% hetastarch), banked donor blood with citrate phosphate dextrose adenine (CPDA-1), fresh donor blood, THAM, sodium bicarbonate (NaHCO3; 1 mEq/ml), high potassium crystalloid cardioplegic solution (HKCCPS), oxygenated crystalloid cardioplegic solution (OCCPS), and adult crystalloid priming solution (AP) per institutional protocol. The solutions were studied at three temperatures: 37 degrees C, 28 degrees C, and 18 degrees C. The null hypothesis stated there was no difference in the BC of the solutions studied. The solutions were first titrated to the same starting pH of 8.0. The solutions were then titrated with a predetermined concentration of hydrochloric acid (HCl) to a pH of 7.0. A higher quantity of H+ added to a solution indicated a greater ability of that solution to buffer H+ within pH limits of 8.0 to 7.0. The data was analyzed with a two way ANOVA and Bonferonni method. A p value < 0.05 was considered to be statistically significant. The significant results of our study indicated that THAM demonstrated the best BC, followed in decreasing order by NaHCO3, banked blood, fresh blood, HKCCPS, AP, OCCPS, Plasmalyte, LR, Hespan, and NS. PMID:10155362

Crawford, R E; Bliss, L M; Schneider, M E; Phelps, V K; Gilmore, R V; Harris, H K; Westendorff, B E; Koenig, G K; Mashburn, P C; Galloway, M W

1995-09-01

387

Anaerobic ammonium oxidation discovered in a denitrifying fluidized bed reactor  

Microsoft Academic Search

Until now, oxidation of ammonium has only been known to proceed under aerobic conditions. Recently, we observed that NH4+ was disappearing from a denitrifying fluidized bed reactor treating effluent from a methanogenic reactor. Both nitrate and ammonium consumption increased with concomitant gas production. A maximum ammonium removal rate of 0.4 kg N · m?3 · d?1 (1.2 mM\\/h) was observed.

A. Mulder; A. A. van de Graaf; L. A. Robertson; J. G. Kuenen

1995-01-01

388

Solid Solutions in the System Ammonium Nitrate-Potassium Nitrate  

Microsoft Academic Search

BY phase work on the system ammonium nitrate-potassium nitrate-water, Janëcke1,2 showed that below 23° C. two types of solid solution can exist: potassium nitrate dissolved in ammonium nitrate (form III) and ammonium nitrate in potassium nitrate (form II). At higher temperatures there is an increasing amount of another phase which is of a different crystalline form from any of the

R. V. Coates; J. M. Crewe

1961-01-01

389

The effects of elevated levels of sodium bicarbonate (NaHCO?) on the acute power output and time to fatigue of maximally stimulated mouse soleus and EDL muscles.  

PubMed

This study examined the effects of elevated buffer capacity [~32 mM HCO?(-)] through administration of sodium bicarbonate (NaHCO?) on maximally stimulated isolated mouse soleus (SOL) and extensor digitorum longus (EDL) muscles undergoing cyclical length changes at 37 °C. The elevated buffering capacity was of an equivalent level to that achieved in humans with acute oral supplementation. We evaluated the acute effects of elevated [HCO?(-)] on (1) maximal acute power output (PO) and (2) time to fatigue to 60 % of maximum control PO (TLIM60), the level of decline in muscle PO observed in humans undertaking similar exercise, using the work loop technique. Acute PO was on average 7.0 ± 4.8 % greater for NaHCO?-treated EDL muscles (P < 0.001; ES = 2.0) and 3.6 ± 1.8 % greater for NaHCO?-treated SOL muscles (P < 0.001; ES = 2.3) compared to CON. Increases in PO were likely due to greater force production throughout shortening. The acute effects of NaHCO? on EDL were significantly greater (P < 0.001; ES = 0.9) than on SOL. Treatment of EDL (P = 0.22; ES = 0.6) and SOL (P = 0.19; ES = 0.9) with NaHCO? did not alter the pattern of fatigue. Although significant differences were not observed in whole group data, the fatigability of muscle performance was variable, suggesting that there might be inter-individual differences in response to NaHCO? supplementation. These results present the best indication to date that NaHCO? has direct peripheral effects on mammalian skeletal muscle resulting in increased acute power output. PMID:23203385

Higgins, M F; Tallis, J; Price, M J; James, R S

2013-05-01

390

The bicarbonate concentration in human saliva does not exceed the plasma level under normal physiological conditions  

Microsoft Academic Search

Depending on the secretion rate and nature of the stimulus applied, the bicarbonate concentration ([HCO3\\u000a –]) in human saliva has been shown to vary from 1 to 60 mM, with the highest values obtained in secretions from the parotid\\u000a and submandibular glands. We conducted the present study on five healthy young males, in order to determine whether human\\u000a saliva [HCO3

Allan Bardow; Joop Madsen; Birgitte Nauntofte

2000-01-01

391

Initiation of stress corrosion cracking for pipeline steels in a carbonate-bicarbonate solution  

Microsoft Academic Search

The linearly increasing stress test (LIST) was used to study the stress corrosion cracking (SCC) behavior of a range of pipeline\\u000a steels in carbonate-bicarbonate solution under stress rate control at different applied potentials. Stress corrosion cracking,\\u000a at potentials below -800 mV(SCE), was attributed to hydrogen embrittlement. Stress corrosion cracking, in the potential range\\u000a from about-700 to -500 mV(SCE), was attributed

Z. F. Wang; A. Atrens

1996-01-01

392

Native, but not thermally denatured lactoferrin solubilizes iron in the presence of bicarbonate ions  

Microsoft Academic Search

Lactoferrin (Lf) can solubilize more than a 70-fold molar equivalent of iron in the presence of bicarbonate anions. Iron solubilized\\u000a by Lf (FeLf) is a useful food product for iron fortification, preventing anaemia with no risk of toxicity. However, the mechanism\\u000a underlying this iron solubilization is not yet well understood. The objective of this study was to investigate the effects

Hiroshi M. Ueno; Ken Kato; Noriko Ueda; Hirokazu Matsui; Hadjime Nakajima

393

Differential Effects of N-Acetylcysteine, Theophylline or Bicarbonate on Contrast-Induced Rat Renal Vasoconstriction  

Microsoft Academic Search

Background: Vasoconstriction and reactive oxygen species (ROS) accumulation following contrast media (CM) injection are the key factors triggering CM-induced nephropathy. We compared the effects of N-acetylcysteine (NAC), theophylline or sodium bicarbonate on intrarenal vasoconstriction and ROS generation in a rat model of CM-induced nephropathy. Methods: Following a 3-day dehydration, Sprague-Dawley rats received CM (Telebrix) or sham ‘CM’ injection of 0.9%

Shai Efrati; Sylvia Berman; Ilia Ilgiyeav; Yariv Siman-Tov; Zhan Averbukh; Joshua Weissgarten

2009-01-01

394

Effect of cimetidine and sodium bicarbonate on pancreatic replacement therapy in cystic fibrosis  

Microsoft Academic Search

Fifteen patients with cystic fibrosis and pancreatic insufficiency were studied during four randomised seven day treatment periods in which they received only pancreatic supplement (Pancrelipase, 27 capsules per day) or supplement plus cimetidine (20 mg\\/kg body weight\\/24 h) or sodium bicarbonate (15 g\\/m2\\/24 h) alone or in combination. Dietary intake was not fixed but was restricted to foods of known

P R Durie; L Bell; W Linton; M L Corey; G G Forstner

1980-01-01

395

Epinephrine and sodium bicarbonate during CPR following asphyxial cardiac arrest in rats  

Microsoft Academic Search

Although high-dose epinephrine during CPR improves coronary perfusion pressure (CoPP) and rate of return of spontaneous circulation (ROSC) in some models, its impact on long term outcome (? 72 h) has not been evaluated. Previous studies of sodium bicarbonate (NaHCO3) therapy during CPR indicate that beneficial effects may be dependent on epinephrine (EPI) dose. We hypothesized that EPI and NaHCO3

Robert W. Neumar; Nicholas G. Bircher; Ka Ming Sim; Fung Xiao; Kathy Swales Zadach; Ann Radovsky; Laurence Katz; Ewe Ebmeyer; Peter Safar

1995-01-01

396

Towards a sustainable synthesis of formate salts: combined catalytic methanol dehydrogenation and bicarbonate hydrogenation.  

PubMed

Formate salts are important chemicals widely used in everyday products. The current industrial-scale manufacture of formates requires CO at high pressure and harsh reaction conditions. Herein, we describe a new process for these products without the utilization of hazardous gases and chemicals. By application of ruthenium pincer complexes, a simultaneous methanol dehydrogenation and bicarbonate hydrogenation reaction proceeds, which provides a green synthesis of formate salts with excellent TON (>18?000), TOF (>1300?h(-1) ), and yield (>90?%). PMID:24888820

Liu, Qiang; Wu, Lipeng; Gülak, Samet; Rockstroh, Nils; Jackstell, Ralf; Beller, Matthias

2014-07-01

397

Sodium bicarbonate reduces viability and alters aflatoxin distribution of Aspergillus parasiticus in Czapek's agar.  

PubMed Central

The potential of sodium bicarbonate to inhibit growth of and aflatoxin synthesis by Aspergillus parasiticus was examined in Czapek's agar (CA), a medium in which fluorescence under UV light indicates aflatoxin production. Incorporation of sodium bicarbonate (SB) into CA at 0.011, 0.022, and 0.033 mol% reduced cell viability 63-, 10(3)-, and greater than 10(7)-fold, respectively. Colonies resulting from surviving cells did not fluoresce under UV light, but thin-layer chromatography analysis of culture extracts detected aflatoxins. Potassium bicarbonate (KB) at 0.011 and 0.022 mol% produced inhibitory effects similar to those of SB, but NaCl and silica had no effect. After 7 days, control cultures had the normal aflatoxin distribution (B1 greater than G1 greater than B2 greater than G2), but this distribution shifted to B2 greater than B1 approximately equal to G2 greater than G1 during prolonged incubation. Cultures supplemented with SB and KB contained mostly aflatoxins B1 and G1 after 28 days. Both SB and KB raised the pH of CA to 7.5 to 8.5 at the time of growth. Culture growth on CA adjusted to pH 7.5 to 8.5 with NaOH was not inhibited but exhibited reduced fluorescence and elevated levels of aflatoxins B1 and G1. Thus, while bicarbonate inhibition of growth could not be attributed to pH elevation, the lack of culture fluorescence on CA-SB and CA-KB and the altered aflatoxin distribution were caused by the ability of SB and KB to elevate pH.

Montville, T J; Goldstein, P K

1987-01-01

398

Reversal of flecainide-induced ventricular arrhythmia by hypertonic sodium bicarbonate in dogs  

Microsoft Academic Search

Flecainide occasionally produces incessant ventricular tachycardia that is difficult to treat. Reports of uncontrolled clinical studies have suggested a therapeutic role for hypertonic sodium bicarbonate (NaHCO3). To test this observation, spontaneous and pacing-induced arrhythmia canine models were designed. In the spontaneous model, flecainide was infused at 0.5 mg\\/kg\\/min until ventricular tachycardia occurred spontaneously. In the pacing-induced model, flecainide was infused

David M Salerno; Maryann M Murakami; Roland B Johnston; Daniel E Keyler; Paul R Pentel

1995-01-01

399

Evaluation of resveratrol oxidation in vitro and the crucial role of bicarbonate ions.  

PubMed

Polyphenols can oxidize in culture medium and produce artifacts in cell culture studies. However, the extent and mechanism of the oxidation of resveratrol, a polyphenol abundant in red wine, is unclear. We investigated the oxidation of resveratrol in vitro and the effects of various components of the culture medium on the degradation of resveratrol and the production of H(2)O(2). We found that 96% of resveratrol at a concentration of 200 microM was degraded in Base Modified Eagle Medium after 24 h of incubation at 37 degrees C, producing about 90 microM of H(2)O(2). Including sodium bicarbonate in the medium markedly stimulated resveratrol degradation and H(2)O(2) production. In sum, we found that bicarbonate ions played a crucial role in the oxidative degradation of resveratrol in vitro, and that the degradation of resveratrol can be avoided by withdrawing sodium bicarbonate from the medium. A mechanism for the oxidation of resveratrol is proposed. PMID:20057154

Yang, Nae-Cherng; Lee, Cheng-Hao; Song, Tuzz-Ying

2010-01-01

400

A new role for bicarbonate secretion in cervico-uterine mucus release  

PubMed Central

Cervical mucus thinning and release during the female reproductive cycle is thought to rely mainly on fluid secretion. However, we now find that mucus released from the murine reproductive tract critically depends upon concurrent bicarbonate (HCO3?) secretion. Prostaglandin E2 (PGE2)- and carbachol-stimulated mucus release was severely inhibited in the absence of serosal HCO3?, HCO3? transport, or functional cystic fibrosis transmembrane conductance regulator (CFTR). In contrast to mucus release, PGE2- and carbachol-stimulated fluid secretion was not dependent on bicarbonate or on CFTR, but was completely blocked by niflumic acid. We found stimulated mucus release was severely impaired in the cystic fibrosis ?F508 reproductive tract, even though stimulated fluid secretion was preserved. Thus, CFTR mutations and/or poor bicarbonate secretion may be associated with reduced female fertility associated with abnormal mucus and specifically, may account for the increased viscosity and lack of cyclical changes in cervical mucus long noted in women with cystic fibrosis.

Muchekehu, Ruth W; Quinton, Paul M

2010-01-01

401

Differential responses in pear and quince genotypes induced by Fe deficiency and bicarbonate.  

PubMed

Most of the studies carried out on Fe deficiency condition in arboreous plants have been performed, with the exception of those carried out on plants grown in the field, in hydroponic culture utilizing a total iron depletion growth condition. This can cause great stress to plants. By introducing Fe deficiency induced by the presence of bicarbonate, we found significant differences between Pyrus communis L. cv. Conference and Cydonia oblonga Mill. BA29 and MA clones, characterized by different levels of tolerance to chlorosis. Pigment content and the main protein-pigment complexes were investigated by HPLC and protein gel blot analysis, respectively. While similar changes in the structural organization of photosystems (PSs) were observed in both species under Fe deficiency, a different reorganization of the photosynthetic apparatus was found in the presence of bicarbonate between tolerant and susceptible genotypes, in agreement with the photosynthetic electron transport rate measured in isolated thylakoids. In order to characterize the intrinsic factors determining the efficiency of iron uptake in a tolerant genotype, the main mechanisms induced by Fe deficiency in Strategy I species, such as Fe3+-chelate reductase (EC 1.16.1.7) and H+-ATPase (EC 3.6.3.6) activities, were also investigated. We demonstrate that physiological and biochemical root responses in quince and pear are differentially affected by iron starvation and bicarbonate supply, and we show a high correlation between tolerance and Strategy I activation. PMID:19269060

Donnini, Silvia; Castagna, Antonella; Ranieri, Annamaria; Zocchi, Graziano

2009-07-15

402

Physiological responses of Tunisian grapevine varieties to bicarbonate-induced iron deficiency.  

PubMed

Plants are frequently submitted to iron deficiency when growing on calcareous soils, which contain high concentrations of bicarbonate. The purpose of this study was to investigate the variability of physiological responses of Tunisian grapevine varieties to bicarbonate-induced iron chlorosis. Vine woodcuttings of seven autochthonous Tunisian varieties (Khamri, Mahdaoui, Blan3, Saouadi, Arich Dressé, Beldi and Balta4), two rootstocks (140Ru and S.O.4), and an introduced table variety (Cardinal) were cultivated on inert sand for 2 months using a complete nutrient solution (20 microM Fe) that was either well supplied or not supplied with 10 mM HCO3-. Young leaves of plants cultivated on bicarbonate-enriched medium showed characteristic symptoms of iron chlorosis, although the intensity of the symptoms depended on the variety and the rootstock. Chlorosis score confirmed these observations since the most sensitive varieties showed the highest values. This variability in tolerance to iron deficiency was also displayed when analysing the physiological parameters (shoot length, plant dry weight, and chlorophyll concentration) and the iron contents in the 4th leaf. Analysis of morphological and physiological parameters showed three behaviour groups. The first one corresponded to tolerant varieties (Khamri, Mahdaoui, and the root-stock: 140Ru), the second included moderately tolerant vines (Saouadi, Arich Dressé, Blanc3, and the rootstock: S.O.4) and the third represented the sensitive ones (Balta4, Beldi, and Cardinal). PMID:15832686

Ksouri, Riadh; Gharsalli, Mohamed; Lachaal, Mokhtar

2005-03-01

403

Uranium(VI) interactions with mackinawite in the presence and absence of bicarbonate and oxygen  

USGS Publications Warehouse

Mackinawite, Fe(II)S, samples loaded with uranium (10-5, 10-4, and 10-3 mol U/g FeS) at pH 5, 7, and 9, were characterized using X-ray absorption spectroscopy and X-ray diffraction to determine the effects of pH, bicarbonate, and oxidation on uptake. Under anoxic conditions, a 5 g/L suspension of mackinawite lowered 5 × 10-5 M uranium(VI) to below 30 ppb (1.26 × 10-7 M) U. Between 82 and 88% of the uranium removed from solution by mackinawite was U(IV) and was nearly completely reduced to U(IV) when 0.012 M bicarbonate was added. Near-neighbor coordination consisting of uranium–oxygen and uranium-uranium distances indicates the formation of uraninite in the presence and absence of bicarbonate, suggesting reductive precipitation as the dominant removal mechanism. Following equilibration in air, mackinawite was oxidized to mainly goethite and sulfur and about 76% of U(IV) was reoxidized to U(VI) with coordination of uranium to axial and equatorial oxygen, similar to uranyl. Additionally, uranium-iron distances, typical of coprecipitation of uranium with iron oxides, and uranium-sulfur distances indicating bidentate coordination of U(VI) to sulfate were evident. The affinity of mackinawite and its oxidation products for U(VI) provides impetus for further study of mackinawite as a potential reactive medium for remediation of uranium-contaminated water.

Gallegos, Tanya J.; Fuller, Christopher C.; Webb, Samuel M.; Betterton, William J.

2013-01-01

404

Can potassium citrate replace sodium bicarbonate and potassium chloride of oral rehydration solution?  

PubMed Central

Ninety four children aged less than 5 years with diarrhoeal dehydration and acidosis were treated randomly with either World Health Organisation (WHO) oral rehydration solution containing sodium chloride, potassium chloride, sodium bicarbonate and glucose or an oral solution with tripotassium citrate monohydrate replacing the sodium bicarbonate and potassium chloride in the WHO solution. Fifty five children (58%) were hypokalaemic (potassium less than 3.5 mmol/l) on admission. All but two in the citrate group were successfully treated. There were no significant differences in rehydration solution intake, stool output, gain in body weight, and fall in plasma specific gravity and haematocrit between the two treatment groups after 48 hours' treatment. Significant improvement in the serum potassium concentration was observed in the hypokalaemic children receiving potassium citrate solution compared with children receiving WHO solution after 24 and 48 hours' treatment. None developed hyperkalaemia. Although children receiving potassium citrate solution corrected their acidosis at a slower rate than the WHO solution group during the first 24 hours, by 48 hours satisfactory correction was observed in all. Tripotassium citrate can safely replace sodium bicarbonate and potassium chloride and may be the most useful and beneficial treatment for diarrhoea and associated hypokalaemia.

Islam, M R

1985-01-01

405

The Sodium Bicarbonate Cotransporter (NBCe1) Is Essential for Normal Development of Mouse Dentition*  

PubMed Central

Proximal renal tubular acidosis (pRTA) is a syndrome caused by abnormal proximal tubule reabsorption of bicarbonate resulting in metabolic acidosis. Patients with mutations to the SLC4A4 gene (coding for the sodium bicarbonate cotransporter NBCe1), have pRTA, growth delay, ocular defects, and enamel abnormalities. In an earlier report, we provided the first evidence that enamel cells, the ameloblasts, express NBCe1 in a polarized fashion, thereby contributing to trans-cellular bicarbonate transport. To determine whether NBCe1 plays a critical role in enamel development, we studied the expression of NBCe1 at various stages of enamel formation in wild-type mice and characterized the biophysical properties of enamel in NBCe1?/? animals. The enamel of NBCe1?/? animals was extremely hypomineralized and weak with an abnormal prismatic architecture. The expression profile of amelogenin, a known enamel-specific gene, was not altered in NBCe1?/? animals. Our results show for the first time that NBCe1 expression is required for the development of normal enamel. This study provides a mechanistic model to account for enamel abnormalities in certain patients with pRTA.

Lacruz, Rodrigo S.; Nanci, Antonio; White, Shane N.; Wen, Xin; Wang, HongJun; Zalzal, Sylvia F.; Luong, Vivian Q.; Schuetter, Verna L.; Conti, Peter S.; Kurtz, Ira; Paine, Michael L.

2010-01-01

406

Evidence for a Detrimental Effect of Bicarbonate Therapy in Hypoxic Lactic Acidosis  

NASA Astrophysics Data System (ADS)

Lactic acidosis, a clinical syndrome caused by the accumulation of lactic acid, is characterized by lactate concentration in blood greater than 5 mM. Therapy usually consists of intravenous sodium bicarbonate (NaHCO3), but resultant mortality is greater than 60 percent. The metabolic and systemic effects of NaHCO3 therapy of hypoxic lactic acidosis in dogs were studied and compared to the effects of sodium chloride or no therapy. Sodium bicarbonate elevated blood lactate concentrations to a greater extent than did either sodium chloride or no treatment. Despite the infusion of NaHCO3, both arterial pH and bicarbonate concentration decreased by a similar amount in all three groups of dogs. Additional detrimental effects of NaHCO3 were observed on the cardiovascular system, including decreases in cardiac output and blood pressure that were not observed with either sodium chloride or no treatment. Thus there is evidence for a harmful effect of NaHCO3 in the treatment of hypoxic lactic acidosis.

Graf, Helmut; Leach, William; Arieff, Allen I.

1985-02-01

407

EFFECTS OF SODIUM BICARBONATE INGESTION ON PERFORMANCE AND PERCEPTUAL RESPONSES IN A LABORATORY-SIMULATED BMX CYCLING QUALIFICATION SERIES  

Microsoft Academic Search

Zabala, M, Requena, B, Sanchez-Munoz, C, Gonzalez-Badillo, JJ, Garcõ´a, I, Oopik, V, and Paasuke, M. Effects of sodium bicarbonate ingestion on performance and perceptual responses in a laboratory-simulated BMX cycling qualification series. J Strength Cond Res 22(5): 1645-1653, 2008—The objective of this study was to examine the effect of sodium bicarbonate (NaHCO32) ingestion on performance and perceptual responses in a

MIKEL ZABALA; BERNARDO REQUENA; CRISTOBAL SANCHEZ-MUNOZ; JUAN JOSEGONZALEZ-BADILLO; INMACULADA GARCIA; VAHUR OOPIK; MATI PAASUKE

408

Influence of Dietary Sodium and Potassium Bicarbonate and Total Potassium on Heat-Stressed Lactating Dairy Cows1  

Microsoft Academic Search

Objectives were to study effects of heat stress, 0 or .85% sodium bicarbonate, 0 or 1.0% potassium bicarbonate, and 1.0 or 1.5% total dietary potassium on production and physiological responses of dairy cows. Eighteen lactating Holsteins were assigned to shade (control) or no shade (heat stress) lots continuously for three consecutive 35-day periods and to different dietary treatments each period.

P. L. Schneider; D. K. Beede; C. J. Wilcox; R. J. Collier

1984-01-01

409

Effect of Feeding Sodium and Potassium Bicarbonate on Milk Fat, Rumen pH, and Volatile Fatty Acid Production1  

Microsoft Academic Search

SUM~M:ARY Sodium or potassium bicarbonates (1 lb\\/day) were added to the rations of cows fed grain to appetite and 2 lb. of long or pelleted hay. These bicarbonates prevented the decline in milk fat percentage frequently associated with such rations. The pH of the rumen contents was increased, but the molar proportion of the acids was not appreciably altered. The

R. S. Emery; L. D. Brown

1961-01-01

410

Effect of Oral Sodium Bicarbonate Supplementation on Interdialytic Weight Gain, Plasma Sodium Concentrations and Predialysis Blood Pressure in Hemodialysis Patients  

Microsoft Academic Search

Background: Correction of metabolic acidosis in dialysis patients should be considered of paramount importance. However, consuming sodium bicarbonate tablets during the interdialytic interval to reach predialysis bicarbonate levels of 23–24 mmol\\/l is not widespread due to the fear of greater interdialytic weight gain and fluid overload. For this reason we investigated in a cross-sectional and in an interventional study the

Ezio Movilli; Paola Gaggia; Corrado Camerini; Giuliano Brunori; Valerio Vizzardi; Giovanni Cancarini

2005-01-01

411

Diversity of ammonium-oxidizing bacteria in a granular sludge anaerobic ammonium-oxidizing (anammox) reactor.  

PubMed

The ammonium-oxidizing microbial community was investigated in a granular sludge anaerobic ammonium-oxidizing (anammox) reactor that was operated for about 1 year with high anaerobic ammonium oxidation activity (up to 0.8 kg NH(4)(+)-N m(-3) day(-1)). A Planctomycetales-specific 16S rRNA gene library was constructed to analyse the diversity of the anaerobic ammonium-oxidizing bacteria (AnAOB). Most of the specifically amplified sequences (15/16) were similar to each other (> 99%) but were distantly related to all of the previously recognized sequences (< 94%), with the exception of an unclassified anammox-related clone, KSU-1 (98%). An ammonia monooxygenase (amoA) gene library was also analysed to investigate the diversity of 'aerobic' ammonium-oxidizing bacteria (AAOB) from the beta-Proteobacteria. Most of the amoA gene fragments (53/55) clustered in the Nitrosomonas europaea-Nitrosococcus mobilis group which has been reported to prevail under oxygen-limiting conditions. The quantitative results from real-time polymerase chain reaction (PCR) amplification showed that the dominant AnAOB comprised approximately 50% of the total bacterial 16S rRNA genes in the reactor, whereas the AAOB of beta-Proteobacteria represented only about 3%. A large fragment (4008 bp) of the rRNA gene cluster of the dominant AnAOB (AS-1) in this reactor sludge was sequenced and compared with sequences of other Planctomycetales including four anammox-related candidate genera. The partial sequence of hydrazine-oxidizing enzyme (hzo) of dominant AnAOB was also identified using new designed primers. Based on this analysis, we propose to tentatively name this new AnAOB Candidatus'Jettenia asiatica'. PMID:18479446

Quan, Zhe-Xue; Rhee, Sung-Keun; Zuo, Jian-E; Yang, Yang; Bae, Jin-Woo; Park, Ja Ryeong; Lee, Sung-Taik; Park, Yong-Ha

2008-11-01

412

Distinct and additive effects of sodium bicarbonate and continuous mild heat stress on fiber type shift via calcineurin/NFAT pathway in human skeletal myoblasts.  

PubMed

Ingestion of sodium bicarbonate (NaHCO3) is known to enhance athletic performance, probably via increased extracellular buffering capacity. At present, little is known about the direct effects of NaHCO3 on myogenesis, especially in vitro. Here, we examined the effects of NaHCO3 and the combined effects of NaHCO3 and continuous mild heat stress (CMHS) at 39°C on the differentiation of human skeletal muscle myoblasts (HSMMs). Levels of myosin heavy chain (MyHC) type I mRNA increased with increasing NaHCO3 concentrations; in contrast, those of MyHC IIx decreased. The NaHCO3-induced fast-to-slow shift was additively enhanced by CMHS. Likewise, intracellular calcium levels and expression of three factors, nuclear factor of activated T cells c2 (NFATc2), NFATc4, and peroxisome-proliferator-activated receptor-? coactivator-1?, were upregulated with increasing NaHCO3 concentrations; moreover, these effects of NaHCO3 were additively enhanced by CMHS. Overexpression experiments and small interfering RNA-mediated knockdown experiments confirmed that NFATc2 and NFATc4 were involved in MyHC I regulation. The present study provided evidence that NaHCO3 and CMHS distinctly and additively induced a fast-to-slow fiber type shift through changes in intracellular calcium levels and the modulation of calcium signaling. PMID:23703530

Yamaguchi, Tetsuo; Omori, Maiko; Tanaka, Nobuho; Fukui, Naoshi

2013-08-01

413

Defending Embedded Systems Against Buffer Overflow via Hardware\\/Software  

Microsoft Academic Search

Buffer overflow attacks have been causing serious secu- rity problems for decades. With more embedded systems networked, it becomes an important research problem to defend embedded systems against buffer overflow attacks. In this paper, we propose the Hardware\\/Software Address Protection (HSAP) technique to solve this problem. We first classify buffer overflow attacks into two categories (stack smashing attacks and function

Zili Shao; Qingfeng Zhuge; Yi He; Edwin Hsing-mean Sha

2003-01-01

414

On the design of power buffer and its applications  

Microsoft Academic Search

A power electronics-based buffer is examined in which through control of its PWM converters, the buffer-load combination is driven to operate under either constant power or constant impedance modes. A battery, incorporated within the buffer, provides the energy storage facility to facilitate the necessary power flow control. Real power demand from upstream supply is regulated under fault condition, and the

S. S. Choi; X. Y. Wang; D. M. Vilathgamuwa

2008-01-01

415

Determination of Sr in soil by tungsten coil atomic emission spectrometry  

Microsoft Academic Search

Strontium was determined in soil by tungsten coil atomic emission spectrometry (WCAES). Since aluminum enhances strontium emission and is a common component of soil, it was first necessary to develop a method to remove aluminum from digested soil solutions. This was accomplished by buffering solutions to a pH of 5.5 with ammonium bicarbonate. Each buffered solution was filtered through a

Arthur L. Salido; Bradley T. Jones

416

A bicarbonate ion as a general base in the mechanism of peptide hydrolysis by dizinc leucine aminopeptidase  

PubMed Central

The active sites of aminopeptidase A (PepA) from Escherichia coli and leucine aminopeptidase from bovine lens are isostructural, as shown by x-ray structures at 2.5 ? and 1.6 ? resolution, respectively. In both structures, a bicarbonate anion is bound to an arginine side chain (Arg-356 in PepA and Arg-336 in leucine aminopeptidase) very near two catalytic zinc ions. It is shown that PepA is activated about 10-fold by bicarbonate when l-leucine p-nitroanilide is used as a substrate. No activation by bicarbonate ions is found for mutants R356A, R356K, R356M, and R356E of PepA. In the suggested mechanism, the bicarbonate anion is proposed to facilitate proton transfer from a zinc-bridging water nucleophile to the peptide leaving group. Thus, the function of the bicarbonate ion as a general base is similar to the catalytic role of carboxylate side chains in the presumed mechanisms of other dizinc or monozinc peptidases. A mutational analysis shows that Arg-356 influences activity by binding the bicarbonate ion but is not essential for activity. Mutation of the catalytic Lys-282 reduces kcat/Km about 10,000-fold.

Strater, Norbert; Sun, Lee; Kantrowitz, E. R.; Lipscomb, William N.

1999-01-01

417

Augmented bicarbonate reabsorption by both the proximal and distal nephron maintains chloride-deplete metabolic alkalosis in rats.  

PubMed Central

Whether augmented bicarbonate reabsorption by renal tubular epithelium contributes to the maintenance of chloride-deplete metabolic alkalosis is not clear. This study used free-flow micropuncture to investigate bicarbonate reabsorption by surface nephron segments in a rat model of diuretic-induced alkalosis compared to control. The proximal and distal nephron of the alkalotic animals had higher values for both delivered load to and absolute reabsorption from these segments. The proximal tubules of alkalotic and control animals had similar values for the slopes of the linear regression of delivered load vs. reabsorption and for the bicarbonate tubular fluid to plasma (TF/P) ratio at the late proximal tubule. By contrast, the corresponding analysis for the distal segment of alkalotic animals revealed a greater slope (0.98 vs. 0.81, P less than 0.003) and a smaller bicarbonate TF/P ratio at the late distal tubule (0.10 vs. 0.16, P less than 0.006). The data indicate that augmented bicarbonate reabsorption by both the proximal and distal nephron contributes to maintaining the alkalosis of this model. The data suggest primary stimulation of bicarbonate reabsorption in the distal nephron and load-dependent reabsorption in the proximal tubule.

Wesson, D E

1989-01-01

418

The stoichiometry of the electrogenic sodium bicarbonate cotransporter NBC1 is cell-type dependent  

PubMed Central

The pancreatic variant of the sodium bicarbonate cotransporter, pNBC1, mediates basolateral bicarbonate influx in the exocrine pancreas by coupling the transport of bicarbonate to that of sodium, with a 2 HCO3?:1 Na+ stoichiometry. The kidney variant, kNBC1, mediates basolateral bicarbonate efflux in the proximal tubule by coupling the transport of 3 HCO3? to 1 Na+. The molecular basis underlying the different stoichiometries is not known. pNBC1 and kNBC1 are 93 % identical to each other with 41 N-terminal amino acids of kNBC1 replaced by 85 distinct amino acids in pNBC1. In this study we tested the hypothesis that the differences in stoichiometry are related to the difference between the N-termini of the two proteins. Mouse renal proximal tubule and collecting duct cells, deficient in both pNBC1- and kNBC1-mediated electrogenic sodium bicarbonate cotransport function were transfected with either pNBC1 or kNBC1. Cells were grown on a permeable support to confluence, mounted in an Ussing chamber and permeabilized apically with amphotericin B. Current through the cotransporter was isolated as the difference current due to the reversible inhibitor dinitrostilbene disulfonate. The stoichiometry was calculated from the reversal potential by measuring the current-voltage relationships of the cotransporter at different Na+ concentration gradients. Our data indicate that both kNBC1 and pNBC1 can exhibit either a 2:1 or 3:1 stoichiometry depending on the cell type in which each is expressed. In proximal tubule cells, both pNBC1 and kNBC1 exhibit a 3 HCO3?:1 Na+ stoichiometry, whereas in collecting duct cells, they have a 2:1 stoichiometry. These data argue against the hypothesis that the stoichiometric differences are related to the difference between the N-termini of the two proteins. Moreover, the results suggest that as yet unidentified cellular factor(s) may modify the stoichiometry of these cotransporters.

Gross, E; Hawkins, K; Abuladze, N; Pushkin, A; Cotton, C U; Hopfer, U; Kurtz, I

2001-01-01

419

Buffer for a gamma-insensitive optical sensor with gas and a buffer assembly  

DOEpatents

A buffer assembly for a gamma-insensitive gas avalanche focal plane array operating in the ultra-violet/visible/infrared energy wavelengths and using a photocathode and an avalanche gas located in a gap between an anode and the photocathode. The buffer assembly functions to eliminate chemical compatibility between the gas composition and the materials of the photocathode. The buffer assembly in the described embodiment is composed of two sections, a first section constructed of glass honeycomb under vacuum and a second section defining a thin barrier film or membrane constructed, for example, of Al and Be, which is attached to and supported by the honeycomb. The honeycomb section, in turn, is supported by and adjacent to the photocathode.

Kruger, Hans W. (Walnut Creek, CA)

1994-01-01

420

Buffer for a gamma-insensitive optical sensor with gas and a buffer assembly  

DOEpatents

A buffer assembly is disclosed for a gamma-insensitive gas avalanche focal plane array operating in the ultra-violet/visible/infrared energy wavelengths and using a photocathode and an avalanche gas located in a gap between an anode and the photocathode. The buffer assembly functions to eliminate chemical compatibility between the gas composition and the materials of the photocathode. The buffer assembly in the described embodiment is composed of two sections, a first section constructed of glass honeycomb under vacuum and a second section defining a thin barrier film or membrane constructed, for example, of Al and Be, which is attached to and supported by the honeycomb. The honeycomb section, in turn, is supported by and adjacent to the photocathode. 7 figures.

Kruger, H.W.

1994-05-10

421

How does glutamine synthetase activity determine plant tolerance to ammonium?  

PubMed

The wide range of plant responses to ammonium nutrition can be used to study the way ammonium interferes with plant metabolism and to assess some characteristics related with ammonium tolerance by plants. In this work we investigated the hypothesis of plant tolerance to ammonium being related with the plants' capacity to maintain high levels of inorganic nitrogen assimilation in the roots. Plants of several species (Spinacia oleracea L., Lycopersicon esculentum L., Lactuca sativa L., Pisum sativum L. and Lupinus albus L.) were grown in the presence of distinct concentrations (0.5, 1.5, 3 and 6 mM) of nitrate and ammonium. The relative contributions of the activity of the key enzymes glutamine synthetase (GS; under light and dark conditions) and glutamate dehydrogenase (GDH) were determined. The main plant organs of nitrogen assimilation (root or shoot) to plant tolerance to ammonium were assessed. The results show that only plants that are able to maintain high levels of GS activity in the dark (either in leaves or in roots) and high root GDH activities accumulate equal amounts of biomass independently of the nitrogen source available to the root medium and thus are ammonium tolerant. Plant species with high GS activities in the dark coincide with those displaying a high capacity for nitrogen metabolism in the roots. Therefore, the main location of nitrogen metabolism (shoots or roots) and the levels of GS activity in the dark are an important strategy for plant ammonium tolerance. The relative contribution of each of these parameters to species tolerance to ammonium is assessed. The efficient sequestration of ammonium in roots, presumably in the vacuoles, is considered as an additional mechanism contributing to plant tolerance to ammonium nutrition. PMID:16292661

Cruz, C; Bio, A F M; Domínguez-Valdivia, M D; Aparicio-Tejo, P M; Lamsfus, C; Martins-Loução, M A

2006-04-01

422

Concentrated Flow through a Riparian Buffer: A Case Study  

NASA Astrophysics Data System (ADS)

Riparian buffers are often used for in-situ treatment of agricultural runoff. Although the benefits of riparian buffers are well recongized, concentration of flow can restrict the efficiency of contaminant removal. This study evaluates flow concentration at a agricultural site near Manhattan, Kansas. Manual and automated GIS analyses of a high-resolution digital elevation model were used to determine the fraction of runoff contributing to each buffer segment. Subsequent simulation of the system in WEPP (Water Erosion and Prediction Project) demonstrates the extent to which flow concentration affects buffer efficiency. Recommendations are presented for the design of adaptive-width buffers.

Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

2005-05-01

423

Liquid Chromatography-Tandem Mass Spectrometry for Analysis of Intestinal Permeability of Loperamide in Physiological Buffer  

PubMed Central

Analysis of in vitro samples with high salt concentrations represents a major challenge for fast and specific quantification with liquid chromatography-tandem mass spectrometry (LC-MS/MS). To investigate the intestinal permeability of opioids in vitro employing the Ussing chamber technique, we developed and validated a fast, sensitive and selective method based on LC–MS/MS for the determination of loperamide in HEPES-buffered Ringer's solution. Chromatographic separation was achieved with an Atlantis dC18 column, 2.1 mm×20 mm, 3 µm particle size and a gradient consisting of methanol/0.1% formic acid and ammonium acetate. The flow rate was 0.7 ml/min, and the total run time was 3 min. For quantification, two mass transitions for loperamide and a deuterated internal standard (methadone-d3) were used. The lower limit of loperamide quantification was 0.2 ng/ml. This new LC-MS/MS method can be used for the detection of loperamide in any experimental setup using HEPES-buffered Ringer's solution as a matrix compound.

Rubelt, Miriam S.; Amasheh, Salah; Grobosch, Thomas; Stein, Christoph

2012-01-01

424

Magnetorheological elastomer and its application on impact buffer  

NASA Astrophysics Data System (ADS)

In this study, a new magnetorheological elastomer (MRE) based buffer is proposed and its vibration isolation performance is investigated. The MRE buffer with a compact structure is first designed in order to accomplish the maximization of the variable stiffness range. The working characteristics of the MRE buffer are then measured and the model of MRE is established. On the basis of the experimental data, the control model of the MRE buffer is also formulated. A two-degree-of-freedom dynamic model with an MRE buffer is then developed. An intelligent control strategy, human simulated intelligent control (HSIC), is proposed to reduce the impact during the drop crash. Finally, the proposed MRE buffer and controller are validated numerically and experimentally. The results show that the proposed MRE buffer and the control strategy can reduce the impact acceleration effectively.

Fu, J.; Yu, M.; Dong, X. M.; Zhu, L. X.

2013-02-01

425

Antifungal activity of gemini quaternary ammonium salts.  

PubMed

A series of gemini quaternary ammonium chlorides and bromides with various alkyl chain and spacer lengths was synthesized. The most active compounds against fungi were chlorides with 10 carbon atoms within the hydrophobic chain. Among these compounds were few with no hemolytic activity at minimal inhibitory concentrations. None of the tested compounds were cytotoxic and mutagenic. Cationic gemini surfactants poorly reduced the adhesion of microorganisms to the polystyrene plate, but inhibited the filamentation of Candida albicans. One of the tested compounds eradicated C. albicans and Rodotorula mucilaginosa biofilm, what could be important in overcoming catheter-associated infections. It was also shown that gemini surfactants enhanced the sensitivity of C. albicans to azoles and polyenes, thus they might be potentially used in combined therapy against fungi. PMID:23827647

Ob??k, Ewa; Piecuch, Agata; Krasowska, Anna; Luczy?ski, Jacek

2013-12-14

426

Hydrothermal oxidation of organic wastes using reclaimed ammonium nitrate  

SciTech Connect

Ammonium nitrate is being studied as an alternative for ammonium perchlorate as an oxidizing agent in Department of Defense 1.1 and 1.3 rocket propellants. Use of ammonium nitrate would eliminate the HCl produced by ammonium perchlorate upon thermal decomposition. To stabilize the ammonium nitrate, which suffers from phase instability, potassium dinitramide (KDN) is added. This increased use of ammonium nitrate will ultimately create a need for environmentally responsible processes to reuse ammonium nitrate extracted from demilitarized rocket motors. Ammonium Nitrate was investigated as an oxidizing agent for methanol, acetic acid and phenol. High removal of organic, ammonia and nitrate was achieved at stoichiometric concentrations. The oxidation of ammonia by nitrate was much faster than the oxidation of either methanol or acetic acid. Phenol, however, was in strong competition with ammonia for the oxidizer (nitrate). Nitrogen products included N{sub 2}, N{sub 2}O, NO{sub 2{sup {minus}}} as well as toxic NO and trace amounts of NO{sub 2}. Carbon products were CO{sub 2}, HCO{sub 3{sup {minus}}}, CO{sub 3}{sup 2{minus}}, and CO.

Proesmans, P.I.; Luan, L.; Buelow, S.J.

1996-04-01

427

Cetyltrimethyl ammonium bromide assisted hydrothermal growth of hematite hollow cubes  

Microsoft Academic Search

Hematite hollow cubes have been prepared by forced hydrolysis of ferric chloride solutions under hydrothermal conditions. The effects of reaction time, reaction temperature and cetyltrimethyl ammonium bromide on the transformation process from akageneite to hematite were investigated in detail. The products were characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. It is found that cetyltrimethyl ammonium

Wei-Wei Wang; Jia-Liang Yao

2010-01-01

428

THE MASS ACCOMMODATION COEFFICIENT OF AMMONIUM NITRATE AEROSOL. (R823514)  

EPA Science Inventory

The mass transfer rate of pure ammonium nitrate between the aerosol and gas phases was quantified experimentally by the use of the tandem differential mobility analyzer/scanning mobility particle sizer (TDMA/SMPS) technique. Ammonium nitrate particles 80-220 nm in diameter...

429

21 CFR 184.1296 - Ferric ammonium citrate.  

Code of Federal Regulations, 2010 CFR

...of 16.5 to 18.5 percent iron, approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish brown or garnet red scales or granules or as a brownish-yellowish powder. (2) Ferric ammonium citrate (iron (III) ammonium...

2009-04-01

430

Ammonium removal from wastewaters using natural New Zealand zeolites  

Microsoft Academic Search

Ammoniacal nitrogen (ammonia and ammonium) in agricultural wastewaters can promote eutrophication of receiving waters and be potentially toxic to fish and other aquatic life. Zeolites, which are hydrated aluminum?silicate minerals, have an affinity for ammonium ions (NH4 ) and are, therefore, potentially useful in removing this contaminant from wastewaters. The major objectives of this study were to evaluate the capacity

M. L. Nguyen; C. C. Tanner

1998-01-01

431

Subcellular localization of ammonium transporters in Dictyostelium discoideum  

Microsoft Academic Search

BACKGROUND: With the exception of vertebrates, most organisms have plasma membrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional purposes. Dictyostelium discoideum has three ammonium transporters, Amts A, B and C. Our present work used fluorescent fusion proteins to determine the cellular localization of the Amts and tested the hypothesis that the transporters mediate

Janet H Kirsten; Yanhua Xiong; Carter T Davis; Charles K Singleton

2008-01-01

432

Anaerobic ammonium oxidation by anammox bacteria in the Black Sea  

Microsoft Academic Search

The availability of fixed inorganic nitrogen (nitrate, nitrite and ammonium) limits primary productivity in many oceanic regions. The conversion of nitrate to N2 by heterotrophic bacteria (denitrification) is believed to be the only important sink for fixed inorganic nitrogen in the ocean. Here we provide evidence for bacteria that anaerobically oxidize ammonium with nitrite to N2 in the world's largest

Marcel M. M. Kuypers; A. Olav Sliekers; Gaute Lavik; Markus Schmid; Bo Barker Jørgensen; J. Gijs Kuenen; Jaap S. Sinninghe Damsté; Marc Strous; Mike S. M. Jetten

2003-01-01

433

Prediction of ammonium salt deposition in hydroprocessing air cooler tubes  

Microsoft Academic Search

Corrosion by wet ammonium salt is one of the main causes to the failure of reactor effluent air cooler (REAC) tubes. Based on a failure case, this paper presents the dynamic process of ammonium chloride (NH4Cl) deposition. A finite element method was used for the numerical simulation of the flow field, temperature field and concentration field to analysis this deposition

Guofu Ou; Haozhe Jin; Haoping Xie; Jing Cao; Jie Qiu

2011-01-01

434

Ammonium ion adsorption with sepiolite: use of transient uptake method  

Microsoft Academic Search

Extent of environmental pollution is increased by technological development. Especially in industrialized areas, ecological equilibrium is affected by wastewater formed with industrial wastes. The more important pollutants for water are nitrogen compounds, which are threatening the human health. Ammonium removal from solution was investigated using Turkish sepiolite, having average particle dimension of 2.05 mm. Ammonium uptake experiments for two different

Suna Balci; Yücel Dinçel

2002-01-01

435

AMMONIUM SULFATE AND BISULFATE FORMATION IN AIR PREHEATERS  

EPA Science Inventory

The overall goal of this study was to investigate the problems which result from deposition of ammonium sulfates in an air preheater. More specifically, the study had three major objectives. The first was to determine the conditions under which ammonium sulfates are expected to f...

436

Ammonium determination in soil extracts by the salicylate method  

Microsoft Academic Search

An ammonium determination, based on formation of a substituted indophenol with sodiumsalicylate as phenolic reagent, has been reexamined. An increase of 70% in absorbancy compared with existing salicylate methods in soil science, and an increase in reproducibility compared with pre?existing equivalent methods in other disciplines were obtained. The method can be applied satisfactorily for ammonium in 2M KCl soil extracts

A. J. Kempers; A. Zweers

1986-01-01

437

Ammonium and methylammonium transport in Rhodobacter sphaeroides.  

PubMed Central

Rhodobacter sphaeroides maintained intracellular ammonium pools of 1.1 to 2.6 mM during growth in several fixed nitrogen sources as well as during diazotrophic growth. Addition of 0.15 mM NH4+ to washed, nitrogen-free cell suspensions was followed by linear uptake of NH4+ from the medium and transient formation of intracellular pools of 0.9 to 1.5 mM NH4+. Transport of NH4+ was shown to be independent of assimilation by glutamine synthetase because intracellular pools of over 1 mM represented NH4+ concentration gradients of at least 100-fold across the cytoplasmic membrane. Ammonium pools of over 1 mM were also found in non-growing cell suspensions in nitrogen-free medium after glutamine synthetase was inhibited with methionine sulfoximine. In NH4+-free cell suspensions, methylammonium (14CH3NH3+) was taken up rapidly, and intracellular concentrations of 0.4 to 0.5 mM were maintained. The 14CH3NH3+ pool was not affected by methionine sulfoximine. Unlike NH4+ uptake, 14CH3NH3+ uptake in nitrogen-free cell suspensions was repressed by growth in NH4+. These results suggest that R. sphaeroides may produce an NH4+-specific transport system in addition to the NH4+/14CH3NH3+ transporter. This second transporter is able to produce normal-size NH4+ pools but has very little affinity for 14CH3NH3+ and is not repressed by growth in high concentrations of NH4+. Images

Cordts, M L; Gibson, J

1987-01-01

438

40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...  

Code of Federal Regulations, 2010 CFR

...Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow...from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow...from ammonium hydroxide - maleic anhydride polymer and...

2009-07-01

439

Solubilities in the ammonium thiosulfate-urea-ammonium nitrate-water system at 0°C  

Microsoft Academic Search

Solubilities in the system CO(NH2)2-NH4NO3-(NH4)2S2O3-H2O were obtained at 0°C and pH values between 6.12 and 7.33. The new composition of matter, (NH4)6(S2O3)2(NO3)2·CO(NH2)2, was identified and characterized chemically and microscopically. Stable high-analyses solution fertilizers can be produced at 0°C utilizing waste ammonium thiosulfate solutions with standard ammonium nitrate and urea fertilizer materials. A 31-0-0-5.6S grade (%N-%P2O5-%K2O-Other) fertilizer solution can be formed

A. W. Frazier; Y. K. Kim; C. L. Griffin

1990-01-01

440

GREENHOUSE TOMATO RESPONSE TO LOW AMMONIUM-NITROGEN CONCENTRATIONS AND DURATION OF AMMONIUM-NITROGEN SUPPLY  

Microsoft Academic Search

High ammonium-nitrogen (NH4-N) concentration in solution may adversely affect greenhouse tomato (Lycopersicon esculentum Mill.) yield, but it has been reported that small NH4-N fractions improve yield and may increase vegetative growth and nutrient element uptake. The effects of short- or long-term supply of NH4-N to tomato plants is not clear, and further information is required to determine how it can

M. Sandoval-Villa; E. A. Guertal; C. W. Wood

2001-01-01