Sample records for acetate buffer solution

  1. Blood biochemical changes in pigs after infusion with acetate-buffered or lactate-buffered crystalloid solutions.

    PubMed

    Keibl, Claudia; Sipos, Wolfgang; Ponschab, Martin; Schlimp, Christoph J

    2015-06-19

    Perioperative fluid therapy is an important component of many medical procedures with animals. Buffered crystalloid solutions avoid inducing metabolic acidosis, but lactated solutions can elevate blood lactate concentrations and acetated solutions have not been thoroughly investigated using large animals. Here, the authors compare blood biochemical parameters in 20 juvenile pigs after perioperative fluid administration of an acetate-buffered solution (Elo-Mel isoton, EMI) or a lactate-buffered solution (lactated Ringer's solution, LRS). The authors measured blood lactate, glucose and electrolyte concentrations before and after administering the test fluid during surgery. Blood lactate concentration after administration was significantly higher in pigs that received LRS than in pigs that received EMI, but glucose and electrolyte concentrations did not differ significantly between treatment groups before or after administration. These findings suggest that EMI might be a preferable option for perioperative fluid therapy in pigs. PMID:26091132

  2. Effect of acetate and carbonate buffers on the photolysis of riboflavin in aqueous solution: a kinetic study.

    PubMed

    Ahmad, Iqbal; Anwar, Zubair; Iqbal, Kefi; Ali, Syed Abid; Mirza, Tania; Khurshid, Adeela; Khurshid, Aqeela; Arsalan, Adeel

    2014-06-01

    The photolysis of riboflavin (RF) in the presence of acetate buffer (pH 3.8-5.6) and carbonate buffer (pH 9.2-10.8) has been studied using a multicomponent spectrophotometric method for the simultaneous assay of RF and its photoproducts. Acetate and carbonate buffers have been found to catalyze the photolysis reaction of RF. The apparent first-order rate constants for the acetate-catalyzed reaction range from 0.20 to 2.86 × 10(-4) s(-1) and for the carbonate-catalyzed reaction from 3.33 to 15.89 × 10(-4) s(-1). The second-order rate constants for the interaction of RF with the acetate and the carbonate ions range from 2.04 to 4.33 × 10(-4) M(-1) s(-1) and from 3.71 to 11.80 × 10(-4) M(-1) s(-1), respectively. The k-pH profile for the acetate-catalyzed reaction is bell shaped and for the carbonate-catalyzed reaction a steep curve. Both HCO3(-) and CO3(2-) ions are involved in the catalysis of the photolysis reaction in alkaline solution. The rate constants for the HCO3(-) and CO3(2-) ions catalyzed reactions are 0.72 and 1.38 × 10(-3) M(-1) s(-1), respectively, indicating a major role of CO3(2-) ions in the catalysis reaction. The loss of RF fluorescence in acetate buffer suggests an interaction between RF and acetate ions to promote the photolysis reaction. The optimum stability of RF solutions is observed in the pH range 5-6, which is suitable for pharmaceutical preparations. PMID:24504494

  3. Glassy carbon electrode modified by conductive polyaniline coating for determination of trace lead and cadmium ions in acetate buffer solution

    Microsoft Academic Search

    Zhaomeng Wang; Erjia Liu; Xing Zhao

    2011-01-01

    Polyaniline (PANI) coatings were electrodeposited on the surfaces of glassy carbon electrodes (GCEs) to form new electrodes, i.e. PANI\\/GCEs. It was found that with increased deposition time, the PANI coatings became more compact while the charge transfer resistance of the coatings became higher. The PANI\\/GCEs were used to detect Cd2+ and Pb2+ ions contained in 0.1M acetate buffer solutions using

  4. Concentrating aqueous acetate solutions with tertiary amines 

    E-print Network

    Lee, Champion

    1993-01-01

    Water may be extracted from aqueous calcium acetate or sodium acetate solutions using low miscibility, low molecular weight tertiary amines, e.g. triethylamine (TEA) and N,N- dietliylmethylaniine (DEMA). This novel extraction technology...

  5. The interaction of sodium dodecyl sulfate and urea with cat-fish collagen solutions in acetate buffer: hydrodynamic and thermodynamic studies.

    PubMed

    Rose, C; Mandal, A B

    1996-02-01

    Cat-fish collagen was extracted and characterized. Shrinkage temperature of cat-fish collagen is 54.5 degrees C. SDS-PAGE pattern indicated that the cat-fish collagen is Type I in nature. The ratio of proline and hydroxyproline is 1:2 and it suggests cat-fish collagen is vertebrate. The molecular weight of cat-fish collagen was determined by using molecular sieve chromatography and it was found to be 3 20,000 Da. The mutual interaction of cat-fish collagen with SDS and urea was studied at various temperatures. The results suggest that the aggregation of collagen is facilitated by the presence of SDS, whereas hindered by urea. The various thermodynamic parameters were estimated from viscosity measurements and the transfer of collagen into SDS micelles, urea and the reverse phenomenon was analysed. These transfer properties are temperature-dependent. Our thermodynamic results are also able to predict the exact denaturation temperature as well as the structural order of water in the collagen in various environments. The hydrated volumes, Vh of collagen in buffer, SDS, and urea environments using Simha-Einstein equation and intrinsic viscosity were also calculated. The low intrinsic viscosity [eta] and high Vh value of collagen in an SDS environment compared to buffer and other environments suggested a more workable system in cosmetic and dermatological preparations. The one and two-hydrogen-bonded models of this collagen in various environments have been analysed. The calculated thermodynamic parameters varied with the concentration of collagen as well as concentration of additives. The change of thermodyanamic parameters from coiled-coil to random-coil conformation upon denaturation of collagen were calculated from the amount of proline and hydroxyproline residues and compared with viscometric results. Denaturation enthalpy of the catfish collagen in buffer, SDS and urea environments has also been determined by differential scanning calorimetric (DSC) measurements, and the results are in good agreement with the viscosity-derived values. The assymmetry and molecular geometry of this collagen in buffer, SDS and urea environments are also computed. Overall, our hydrodynamic and thermodynamic results suggest that the stability of the collagen in the additive environments is in the following order: SDS > buffer > urea. PMID:8852752

  6. A sensitive negative-ion electrospray ionization mass spectrometry detection for metallothionein in tris(hydroxymethyl)aminomethane acetate buffer

    NASA Astrophysics Data System (ADS)

    Shen, Jin-Can; Lu, Su-Ge; Zhuang, Zhi-Xia; Wang, Xiao-Ru; Lee, Frank S. C.

    2005-05-01

    Although positive-ion (PI) electrospray ionisation mass spectrometry (ESI-MS) has been usually applied for the analysis of native metallothioneins (MT) isoforms binding with metal ions, it suffers from the lack of insensitivity under neural conditions because of the low efficiency of protonation during ESI process. In this study, multiply deprotonated metallothionein (Zn7-MT-2a), produced from tris(hydroxymethyl)aminomethane (TRIS) acetate solutions under near neutral condition, was analyzed by negative-ion (NI) ESI-MS. Compared with the ammonium acetate buffer system which has been normally used for ESI-MS experiments, the use of TRIS acetate buffer results in the formation of more abundant ions and higher charge states of MT-2a, and consequently higher intensity is attained. The sensitivity enhancement of the system could be explained by the high gas-phase proton affinity, small molecular volume of the anion (acetate), and the high hydrogen consumption by TRIS in the buffer system, which would all favor the deprotonation of the analyte during NI-ESI process. Factors that may affect the NI-ESI responses, such as acid added in buffer, pH and concentration of TRIS acetate had been evaluated, and the result showed that using acetic acid, lower pH under the pH range evaluated, higher concentration of TRIS acetate all favored the MS detection of MT-2a. Our finding sheds light on a buffer system that may offer substantial sensitivity advantages in the studying of weakly bound, non-covalent complexes such as metal binding MTs, which are usually analyzed under near neutral conditions.

  7. A new strategy to stabilize oxytocin in aqueous solutions: I. The effects of divalent metal ions and citrate buffer.

    PubMed

    Avanti, Christina; Amorij, Jean-Pierre; Setyaningsih, Dewi; Hawe, Andrea; Jiskoot, Wim; Visser, Jan; Kedrov, Alexej; Driessen, Arnold J M; Hinrichs, Wouter L J; Frijlink, Henderik W

    2011-06-01

    In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na(+) and K(+)) and divalent metal ions (Ca(2+), Mg(2+), and Zn(2+)) were tested all as chloride salts. The effect of combinations of buffers and metal ions on the stability of aqueous oxytocin solutions was determined by RP-HPLC and HP-SEC after 4 weeks of storage at either 4°C or 55°C. Addition of sodium or potassium ions to acetate- or citrate-buffered solutions did not increase stability, nor did the addition of divalent metal ions to acetate buffer. However, the stability of aqueous oxytocin in aqueous formulations was improved in the presence of 5 and 10 mM citrate buffer in combination with at least 2 mM CaCl(2), MgCl(2), or ZnCl(2) and depended on the divalent metal ion concentration. Isothermal titration calorimetric measurements were predictive for the stabilization effects observed during the stability study. Formulations in citrate buffer that had an improved stability displayed a strong interaction between oxytocin and Ca(2+), Mg(2+), or Zn(2+), while formulations in acetate buffer did not. In conclusion, our study shows that divalent metal ions in combination with citrate buffer strongly improved the stability of oxytocin in aqueous solutions. PMID:21448747

  8. A nitrilo-tri-acetic-acid/acetic acid route for the deposition of epitaxial cerium oxide films as high temperature superconductor buffer layers

    SciTech Connect

    Thuy, T.T.; Lommens, P.; Narayanan, V.; Van de Velde, N.; De Buysser, K.; Herman, G.G.; Cloet, V. [Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 - S3, 9000 Gent (Belgium); Van Driessche, I., E-mail: Isabel.Vandriessche@UGent.b [Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 - S3, 9000 Gent (Belgium)

    2010-09-15

    A water based cerium oxide precursor solution using nitrilo-tri-acetic-acid (NTA) and acetic acid as complexing agents is described in detail. This precursor solution is used for the deposition of epitaxial CeO{sub 2} layers on Ni-5at%W substrates by dip-coating. The influence of the complexation behavior on the formation of transparent, homogeneous solutions and gels has been studied. It is found that ethylenediamine plays an important role in the gelification. The growth conditions for cerium oxide films were Ar-5% gas processing atmosphere, a solution concentration level of 0.25 M, a dwell time of 60 min at 900 {sup o}C and 5-30 min at 1050 {sup o}C. X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), pole figures and spectroscopic ellipsometry were used to characterize the CeO{sub 2} films with different thicknesses. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) was used to determine the carbon residue level in the surface of the cerium oxide film, which was found to be lower than 0.01%. Textured films with a thickness of 50 nm were obtained. - Graphical abstract: Study of the complexation and hydrolysis behavior of Ce{sup 4+} ions in the presence of nitrilo-tri-acetic acid and the subsequent development of an aqueous chemical solution deposition route suited for the processing of textured CeO{sub 2} buffer layers on Ni-W tapes.

  9. Ozone decomposition in aqueous acetate solutions

    SciTech Connect

    Sehested, K.; Holcman, J.; Bjergbakke, E.; Hart, E.J.

    1987-01-01

    The acetate radical ion reacts with ozone with a rate constant of k = (1.5 +/- 0.5) x 10Z dmT mol s . The products from this reaction are CO2, HCHO, and O2 . By subsequent reaction of the peroxy radical with ozone the acetate radical ion is regenerated through the OH radical. A chain decomposition of ozone takes place. It terminates when the acetate radical ion reacts with oxygen forming the unreactive peroxy acetate radical. The chain is rather short as oxygen is developed, as a result of the ozone consumption. The inhibiting effect of acetate on the ozone decay is rationalized by OH scavenging by acetate and successive reaction of the acetate radical ion with oxygen. Some products from the bimolecular disappearance of the peroxy acetate radicals, however, react further with ozone, reducing the effectiveness of the stabilization.

  10. Sample Questions (1) Phosphate buffered saline (PBS) is a buffer solution commonly used in biological research.

    E-print Network

    California at San Diego, University of

    Sample Questions (1) Phosphate buffered saline (PBS) is a buffer solution commonly used in biological research. It is a water-based salt solution containing sodium phosphate, sodium chloride and of the solutions match those of the human body (isotonic). The most common composition of PBS (1X) has

  11. Effect of Tris-acetate buffer on endotoxin removal from human-like collagen used biomaterials.

    PubMed

    Zhang, Huizhi; Fan, Daidi; Deng, Jianjun; Zhu, Chenghui; Hui, Junfeng; Ma, Xiaoxuan

    2014-09-01

    Protein preparation, which has active ingredients designated for the use of biomaterials and therapeutical protein, is obtained by genetic engineering, but products of genetic engineering are often contaminated by endotoxins. Because endotoxin is a ubiquitous and potent proinflammatory agent, endotoxin removal or depletion from protein is essential for researching any biomaterials. In this study, we have used Tris-acetate (TA) buffer of neutral pH value to evaluate endotoxins absorbed on the Pierce high-capacity endotoxin removal resin. The effects of TA buffer on pH, ionic strength, incubation time as well as human-like collagen (HLC) concentration on eliminating endotoxins are investigated. In the present experiments, we design an optimal method for TA buffer to remove endotoxin from recombinant collagen and use a chromogenic tachypleus amebocyte lysate (TAL) test kit to measure the endotoxin level of HLC. The present results show that, the endotoxins of HLC is dropped to 8.3EU/ml at 25 mM TA buffer (pH7.8) with 150 mM NaCl when setting incubation time at 6h, and HLC recovery is about 96%. Under this experimental condition, it is proved to exhibit high efficiencies of both endotoxin removal and collagen recovery. The structure of treated HLC was explored by Transmission Electron Microscopy (TEM), demonstrating that the property and structure of HLC treated by TA buffer are maintained. Compared to the most widely used endotoxin removal method, Triton X-114 extraction, using TA buffer can obtain the non-toxic HLC without extra treatment for removing the toxic substances in Triton X-114. In addition, the present study aims at establishing a foundation for further work in laboratory animal science and providing a foundation for medical grade biomaterials. PMID:25063101

  12. Application of Acetate Buffer in pH Adjustment of Mash and its Influence on Fuel Ethanol Fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 2M sodium acetate buffer at pH 4.2 was used to adjust pH of liquefied mashes in a simultaneous saccharification and fermentation (SSF) procedure. Although 5 mL of the buffer did not bring the pH values of the mashes (~100 mL) from a sorghum hybrid to 4.2, it kept the system stable (pH from 4.7 to ...

  13. On the Preparation of Buffer Solutions.

    ERIC Educational Resources Information Center

    Thomson, Bruce M.; Kessick, Michael A.

    1981-01-01

    Presents a method, suitable for use on programmable calculators, which allows calculation of the pH and ionic strength (I) of a mixed solution of salts of an acid or amounts necessary to produce a solution of a particular pH and I. Includes limitations when using the calculations described. (SK)

  14. CHEMICAL SOLUTION DEPOSITION BASED OXIDE BUFFERS AND YBCO COATED CONDUCTORS

    SciTech Connect

    Paranthaman, Mariappan Parans [ORNL

    2011-01-01

    We have reviewed briefly the growth of buffer and high temperature superconducting oxide thin films using a chemical solution deposition (CSD) method. In the Rolling-Assisted Biaxially Textured Substrates (RABiTS) process, developed at Oak Ridge National Laboratory, utilizes the thermo mechanical processing to obtain the flexible, biaxially oriented copper, nickel or nickel-alloy substrates. Buffers and Rare Earth Barium Copper Oxide (REBCO) superconductors have been deposited epitaxially on the textured nickel alloy substrates. The starting substrate serves as a template for the REBCO layer, which has substantially fewer weak links. Buffer layers play a major role in fabricating the second generation REBCO wire technology. The main purpose of the buffer layers is to provide a smooth, continuous and chemically inert surface for the growth of the REBCO film, while transferring the texture from the substrate to the superconductor layer. To achieve this, the buffer layers need to be epitaxial to the substrate, i.e. they have to nucleate and grow in the same bi-axial texture provided by the textured metal foil. The most commonly used RABiTS multi-layer architectures consist of a starting template of biaxially textured Ni-5 at.% W (Ni-W) substrate with a seed (first) layer of Yttrium Oxide (Y2O3), a barrier (second) layer of Yttria Stabilized Zirconia (YSZ), and a Cerium Oxide (CeO2) cap (third) layer. These three buffer layers are generally deposited using physical vapor deposition (PVD) techniques such as reactive sputtering. On top of the PVD template, REBCO film is then grown by a chemical solution deposition. This article reviews in detail about the list of oxide buffers and superconductor REBCO films grown epitaxially on single crystal and/or biaxially textured Ni-W substrates using a CSD method.

  15. Evaluation of the acetate buffer attack of a sequential extraction scheme for marine particulate metal speciation studies by scanning electron microscopy with energy dispersive X-ray analysis

    Microsoft Academic Search

    F Baffi; C Ianni; M Ravera; F Soggia; E Magi

    1998-01-01

    Scanning electron microscopy, with energy dispersive X-ray analysis (SEM-EDX), has been used to evaluate and possibly optimize, the first step (acetate buffer attack for exchangeable and carbonatic fractions) of a sequential selective extraction scheme. The extraction has been performed on two different particulates, a certified reference plankton and a real marine suspended particulate, using an increased acetate concentration and various

  16. The vapour pressures of saturated aqueous solutions of magnesium, calcium, nickel and zinc acetates and molar enthalpies of solution of magnesium, calcium, zinc and lead acetates

    Microsoft Academic Search

    Alexander Apelblat; Eli Korin

    2001-01-01

    Vapour pressures of water over saturated solutions of magnesium, calcium, nickel and zinc acetates were determined as a function of temperature. The vapour pressures served to evaluate the water activities, osmotic coefficients and molar enthalpies of vaporization. Molar enthalpies of solution of magnesium acetate tetrahydrate,?solHm (T= 294.71K ;m= 0.01 mol · kg?1) =?(15.65 ± 0.97)kJ · mol?1; calcium acetate,?solHm (T=

  17. Effects of buffered 2.3%, buffered 0.9%, and non-buffered 0.9% irrigation solutions on nasal mucosa after septoplasty.

    PubMed

    Süslü, Nilda; Bajin, Münir Demir; Süslü, Ahmet Emre; O?retmeno?lu, O?uz

    2009-05-01

    A prospective randomized study was designed to compare the effect of different irrigation solutions on mucociliary clearance and nasal patency and to compare the limitations of the used solutions, such as nasal burning by a visual analog scale. Forty-five patients who underwent septoplasty were divided into three groups postoperatively. Each group was administered with 2.3% buffered hypertonic seawater, buffered isotonic saline solution and non-buffered isotonic saline, respectively, as irrigation fluid. Saccharine test and acoustic rhinometer were used to determine mucociliary activity and nasal patency. Patients were asked about the burning sensation using a 10-cm visual analog scale. There was no significant difference in saccharine clearance time (SCT) on the 5th postoperative day between the three groups (P = 0.07). On the 20th day, there was a significant difference in SCT between the hypertonic buffered seawater group and non-buffered isotonic saline (P = 0.003). Buffered hypertonic seawater improved nasal airway patency more than the buffered isotonic saline (P = 0.004). Buffered hypertonic solutions used after endonasal surgery have been advantageous for both mucociliary clearance and postoperative decongestion. PMID:18802718

  18. Hydrolysis and photolysis of flumioxazin in aqueous buffer solutions.

    PubMed

    Kwon, Jeong-Wook; Armbrust, Kevin L; Grey, Timothy L

    2004-09-01

    To determine the degradation rates and degradation products of the herbicide flumioxazin in aqueous buffer solutions (pH 5, 7 and 9), its hydrolysis and photolysis were investigated at 30 degrees C in the dark, and in a growth chamber fitted with fluorescent lamps simulating the UV output of sunlight. The rate of hydrolysis of flumioxazin was accelerated by increasing pH. The t(1/2) values at pH 5, 7 and 9 were 16.4, 9.1 and 0.25 h, respectively. Two degradation products were detected and their structural assignments were made on the basis of LC-MS data. Degradation product I was detected in all buffer solutions while degradation product II was detected in acidic buffer only. Both degradation products appeared to be stable to further hydrolysis. After correcting for the effects of hydrolysis, the photolytic degradation rate also increased as a function of pH and was approximately 10 times higher at pH 7 than that at pH 5, showing t(1/2) values of 4.9 and 41.5 h, respectively. Degradation products formed by photolysis were the same as those formed by hydrolysis. Flumioxazin was degraded more extensively at high pH and should degrade in surface water. PMID:15382510

  19. Closed Form Solution to Simultaneous Buffer Insertion/Sizing and Wire Sizing

    E-print Network

    Chu, Chris C.-N.

    information (i.e., choice for wire width and buffer size) is required. But at the synthesis and planningClosed Form Solution to Simultaneous Buffer Insertion/Sizing and Wire Sizing CHRIS CHU Iowa State problem of an interconnect wire by simultaneously considering buffer insertion, buffer sizing and wire

  20. Advanced titania buffer layer architectures prepared by chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Kunert, J.; Bäcker, M.; Brunkahl, O.; Wesolowski, D.; Edney, C.; Clem, P.; Thomas, N.; Liersch, A.

    2011-08-01

    Chemical solution deposition (CSD) was used to grow high-quality (100) oriented films of SrTiO3 (STO) on CSD CaTiO3 (CTO), Ba0.1Ca0.9TiO3 (BCT) and STO seed and template layers. These template films bridge the lattice misfit between STO and the nickel-tungsten (NiW) substrate, assisting in dense growth of textured STO. Additional niobium (Nb) doping of the STO buffer layer reduces oxygen diffusion which is necessary to avoid undesired oxidation of the NiW. The investigated templates offer suitable alternatives to established standard buffer systems like La2Zr2O7 (LZO) and CeO2 for coated conductors.

  1. Buffered lidocaine and bupivacaine mixture - the ideal local anesthetic solution?

    PubMed

    Best, Corliss A; Best, Alyssa A; Best, Timothy J; Hamilton, Danielle A

    2015-01-01

    The use of injectable local anesthetic solutions to facilitate pain-free surgery is an integral component of many procedures performed by the plastic surgeon. In many instances, a solution that has both rapid onset and prolonged duration of analgesia is optimal. A combination of lidocaine and bupivacaine, plain or with epinephrine, is readily available in most Canadian health care settings where such procedures are performed, and fulfills these criteria. However, commercially available solutions of both medications are acidic and cause a burning sensation on injection. Buffering to neutral pH with sodium bicarbonate is a practical method to mitigate the burning sensation, and has the added benefit of increasing the fraction of nonionized lipid soluble drug available. The authors report on the proportions of the three drugs to yield a neutral pH, and the results of an initial survey regarding the use of the combined solution with epinephrine in hand surgery. PMID:26090348

  2. Effects of buffered 2.3%, buffered 0.9%, and non-buffered 0.9% irrigation solutions on nasal mucosa after septoplasty

    Microsoft Academic Search

    Nilda Süslü; Münir Demir Bajin; Ahmet Emre Süslü; O?uz Ö?retmeno?lu

    2009-01-01

    A prospective randomized study was designed to compare the effect of different irrigation solutions on mucociliary clearance\\u000a and nasal patency and to compare the limitations of the used solutions, such as nasal burning by a visual analog scale. Forty-five\\u000a patients who underwent septoplasty were divided into three groups postoperatively. Each group was administered with 2.3% buffered\\u000a hypertonic seawater, buffered isotonic

  3. Electrochemical behaviour of silver in borate buffer solutions

    NASA Astrophysics Data System (ADS)

    Zaky, Ayman M.; Assaf, Fawzi H.; Abd El Rehim, Sayed S.; Mohamed, Basheer M.

    2004-01-01

    The electrochemical behaviour of Ag in aqueous 0.15 M borax and 0.15 M boric acid buffer solution was studied under various conditions using cyclic voltammetry and potentiostatic techniques. It was found that the anodic polarization curve of Ag in borate buffer solution was characterized by the appearance of two potential regions, active and passive, prior to the oxygen evolution reaction. The active potential region was characterized by the appearance of three anodic peaks, the first two peaks A 1 and A 2 correspond to the oxidation of Ag and formation of [Ag(OH) 2] - soluble compound and a passive film of Ag 2O on the electrode surface. The third anodic peak corresponds to the conversion of both [Ag(OH) 2] - and Ag 2O to Ag 2O 2. X-ray diffraction patterns confirmed the existence of Ag 2O and Ag 2O 2 passive layers on the electrode surface potentiodynamically polarized up to 800 mV. Potentiostatic current transient measurements showed that the formation of Ag 2O and Ag 2O 2 involves a nucleation and growth mechanism under diffusion control.

  4. In situ XANES study of the passive film formed on iron in borate buffer and in sodium acetate

    SciTech Connect

    Oblonsky, L.J.; Ryan, M.P.; Isaacs, S. [and others

    1996-12-31

    The passive film formed on Fe in pH 8.4 borate buffer (0. 1 36 M) over a broad potential range was characterized by in situ XANES (x-ray absorption near edge structure). On stepping the potential to a value between -0.6 V and +0.4 V (MSE), a passive film forms without detectable dissolution. The edge position indicates that the valence state of Fe in the film is 10 {+-} 5% Fe{sup 2+} and 90 {+-} 5% Fe{sup 3+}. Formation of a passive film at potentials between -0.8 V and -0.65 V is associated with dissolution prior to passivation, and a lower average valence state of 17 {+-} 5% Fe{sup 2+} and 83 {+-} 5% Fe{sup 3+}. At -0.9 V, the Fe did not passivate. The passive film that forms in pH 8.2 sodium acetate (0.1 M) at +0.4 V gives an edge similar to the high potential passive film formed in borate buffer, but dissolution occurs prior to passivation.

  5. Photocatalytic decomposition of cortisone acetate in aqueous solution.

    PubMed

    Romão, Joana Sobral; Hamdy, Mohamed S; Mul, Guido; Baltrusaitis, Jonas

    2015-01-23

    The photocatalytic decomposition of cortisone 21-acetate (CA), a model compound for the commonly used steroid, cortisone, was studied. CA was photocatalytically decomposed in a slurry reactor with the initial rates between 0.11 and 0.46 mg L(-1)min(-1) at 10 mg L(-1) concentration, using the following heterogeneous photocatalysts in decreasing order of their catalytic activity: ZnO>Evonik TiO2 P25>Hombikat TiO2>WO3. Due to the lack of ZnO stability in aqueous solutions, TiO2 P25 was chosen for further experiments. The decomposition reaction was found to be pseudo-first order and the rate constant decreased as a function of increasing initial CA concentration. Changing the initial pH of the CA solution did not affect the reaction rate significantly. The decomposition reaction in the presence of the oxidizing sacrificial agent sodium persulfate showed an observed decomposition rate constant of 0.004 min(-1), lower than that obtained for TiO2 P25 (0.040 min(-1)). The highest photocatalytic degradation rate constant was obtained combining both TiO2 P25 and S2O8(2-) (0.071 min(-1)) showing a synergistic effect. No reactive intermediates were detected using LC-MS showing fast photocatalytic decomposition kinetics of CA. PMID:24953705

  6. CLOSED FORM SOLUTION TO SIMULTANEOUS BUFFER INSERTION/SIZING AND WIRE SIZING

    E-print Network

    Chu, Chris C.-N.

    m RD L b l2 CL # of buffers? Segment lengths? Segment widths? Where to insert? Buffer sizes? OUTPUTCLOSED FORM SOLUTION TO SIMULTANEOUS BUFFER INSERTION/SIZING AND WIRE SIZING Chris C. N. Chu and D insert bu ers between any two adjacent segments. The sizes of bu ers and the lengths and widths

  7. The vapour pressures over saturated aqueous solutions of sodium and potassium acetates, chlorates, and perchlorates

    Microsoft Academic Search

    Alexander Apelblat; Emanuel Manzurola

    2007-01-01

    Vapour pressures of water over saturated solutions of sodium acetate, potassium acetate, sodium perchlorate, and potassium perchlorate were determined over the (278 to 318)K temperature range and compared with available in the literature data. The cases of saturated solutions of sodium chlorate and potassium chlorate are also considered. The determined vapour pressures were used to obtain the water activities, the

  8. On the Structure of Cellulose Acetate Molecules in Acetone Solution

    Microsoft Academic Search

    Seymour J. Singer; Herman Mark

    1948-01-01

    Data obtained from sedimentation velocity and viscosity measurements on a series of cellulose acetate fractions in acetone are interpreted in terms of two models, the impenetrable ellipsoid of rotation and the uniform density random coil. The lack of agreement using the former model is shown to be a real effect, rather than one determined by experimental inaccuracy. As other investigations

  9. Corona contraction and polyelectrolyte complexation of polybasic micelles in buffered aqueous solution

    NASA Astrophysics Data System (ADS)

    Laaser, Jennifer; Jiang, Yaming; Reineke, Theresa; Lodge, Timothy

    2015-03-01

    We investigate the pH- and ionic strength-induced contraction of polycationic micelles with a polystyrene core and poly(dimethylaminoethyl methacrylate) corona in buffered aqueous solutions, and report on complexation of these micelles with poly(styrene sulfonate) under varying ionic strength conditions. We find that in monoprotic buffers, the micelle corona behaves as a salted osmotic brush, as has been observed for other block polyelectrolyte micelle systems in unbuffered solutions. In polyprotic buffers, however, we find that concentration of the charged buffer species in the micelle corona shifts the buffer dissociation equilibrium farther toward multivalent species than in the bulk, resulting in an anomalously high degree of corona contraction. In our complexation experiments, we observe multimodal size distributions that evolve on timescales of days to weeks at physiologically relevant ionic strengths, which may have implications for the design of gene- and drug-delivery vehicles using these types of interpolyelectrolyte complexes.

  10. [Influence of buffer solutions on the performance of microbial fuel cell electricity generation].

    PubMed

    Qiang, Lin; Yuan, Lin-jiang; Ding, Qing

    2011-05-01

    Microbial fuel cell (MFC) is a potential green technology due to its application in wastewater treatment and renewable energy generation. Phosphate buffer solution (PBS) has been commonly used in MFC studies to maintain a suitable pH for electricity generating bacteria and/or to increase the solution conductivity. However, it has some drawbacks using PBS in MFC: One is that the addition of a high concentration of phosphate buffer in MFCs is expensive, especially for the application in wastewater treatment; the other is that phosphates can contribute to the eutrophication conditions of water bodies if the effluents are discharged without the removal of phosphates. By adding PBS buffer as the comparison, the study investigated the effect of borax buffer and in the absence of buffer on the performance of electrical power, coulomb efficiency and effluent pH. 200 mmol/L PBS was the best, conductivity was 1.973 mS/cm,the maximum power density was 36.4 mW/m2 and the maximum coulomb efficiency was 2.92%, effluent pH was almost at (7.00 +/- 0.05). 100 mmol/L borax buffer solution, conductivity was 1.553 mS/cm; the maximum power density was 26.2 mW/m2 coulomb efficiency of 6.26%, which was 2.14 times to PBS and greatly increased the electron recovery efficiency with the effluent pH was (7.35 +/- 0.05). While free buffer solution conductivity was 0.314 mS/cm, maximum power density was 27.64 mW/m2; coulomb efficiency was 2.82% and the effluent pH of approximately 7.43. The electrolyte which in absence of buffer solution conductivity was 1/6 of adding PBS buffer, 1/5 of borax buffer, while its power density lower 8.76 mW/mr2 than adding PBS and higher 1.24 mW/m2 than borax buffer. The results showed that adding the suitable concentration of borax buffer may improve the electron recovery efficiency and under batch conditions, MFC run successfully without adding buffer solution to MFC. PMID:21780615

  11. Inhibition of Protein Carbamylation in Urea Solution Using Ammonium Containing Buffers

    PubMed Central

    Sun, Shisheng; Zhou, Jian-Ying; Yang, Weiming; Zhang, Hui

    2013-01-01

    Urea solution is one of the most commonly employed protein denaturants for protease digestion in proteomic studies. However, it has long been recognized that urea solution can cause carbamylation at the N-termini of proteins/peptides and at the side chain amino groups of lysine and arginine residues. Protein/peptide carbamylation blocks protease digestion and affects protein identification and quantification in mass spectrometry analysis by blocking peptide amino groups from isotopic/isobaric labeling and changing peptide charge states, retention times and masses. In addition, protein carbamylation during sample preparation makes it difficult to study in vivo protein carbamylation. In this study, we compared the peptide carbamylation in urea solutions of different buffers and found that ammonium containing buffers were the most effective buffers to inhibit protein carbamylation in urea solution. The possible mechanism of carbamylation inhibition by ammonium containing buffers is discussed, and a revised procedure for the protease digestion of proteins in urea and ammonium containing buffers was developed to facilitate its application in proteomic research. PMID:24161613

  12. Simultaneous pollutant removal and electricity generation in denitrifying microbial fuel cell with boric acid-borate buffer solution.

    PubMed

    Chen, Gang; Zhang, Shaohui; Li, Meng; Wei, Yan

    2015-03-01

    A double-chamber denitrifying microbial fuel cell (MFC), using boric acid-borate buffer solution as an alternative to phosphate buffer solution, was set up to investigate the influence of buffer solution concentration, temperature and external resistance on electricity generation and pollutant removal efficiency. The result revealed that the denitrifying MFC with boric acid-borate buffer solution was successfully started up in 51 days, with a stable cell voltage of 205.1 ± 1.96 mV at an external resistance of 50 ?. Higher concentration of buffer solution favored nitrogen removal and electricity generation. The maximum power density of 8.27 W/m(3) net cathodic chamber was obtained at a buffer solution concentration of 100 mmol/L. An increase in temperature benefitted electricity generation and nitrogen removal. A suitable temperature for this denitrifying MFC was suggested to be 25 °C. Decreasing the external resistance favored nitrogen removal and organic matter consumption by exoelectrogens. PMID:25768227

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

    NSDL National Science Digital Library

    Wiles, Laura K.

    2009-08-15

    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 500?m long by 50?m 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 10?M 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.

  14. EXAMINATION OF DIFFERENT PRESERVATIVES FOR TODARODES PACIFICUS PARALARVAE FIXED WITH BORAX-BUFFERED FORMALIN-SEAWATER SOLUTION

    Microsoft Academic Search

    Tsuneo Goto

    2005-01-01

    The effects of different preservatives on 36 Todarodes pacificus paralarvae were examined. After fixation in a solution of borax-buffered 2-4% formaldehyde in seawater, each dorsal mantle length was measured and dorsal chromatophores were photographed. The paralarvae were divided into the following six different preservatives; 1) 5% phosphate-buffered formalin, 2) 5% borax-buffered formalin, 3) 5% hexamine-buffered formalin, 4) 99% ethanol, 5)

  15. Buffer behavior of brucite in removing copper from acidic solution

    Microsoft Academic Search

    L. Shao; Y. Zhou; J. F. Chen; W. Wu; S. C. Lu

    2005-01-01

    Brucite was employed as a natural adsorbent to explore its capacity of removing Cu2+ from an acidic solution. Experimental results indicate that brucite has a good neutralization capacity for acidity. The final pH of brucite suspensions rises to 3.47 and 7.91 respectively with initial pH of 1.49 and 2.09, and Cu2+ adsorption on brucite is 1.85% and 96.31% accordingly. The

  16. Analytical steady-state solution to the rapid buffering approximation near an open Ca2+ channel.

    PubMed Central

    Smith, G D

    1996-01-01

    We derive an analytical steady-state solution for the Ca2+ profile near an open Ca2+ channel based on a transport equation which describes the buffered diffusion of Ca2+ in the presence of rapid stationary and mobile Ca2+ buffers (Wagner and Keizer, 1994). This steady-state rapid buffering approximation gives an upper bound on local Ca2+ elevations such as Ca2+ puffs or sparks when conditions for the validity of the rapid buffering approximation are met and is an alternative to approximations that assume that mobile buffers are unsaturable. This result also provides an analytical estimate of the cytosolic Ca2+ domain concentration ([Ca2+]d) near a channel pore and shows the dependence of [Ca2+]d on moderate concentrations of endogenous mobile buffer, Ca2+ indicator dye, and bulk cytosolic Ca2+. Assuming a simple relationship between [Ca2+]d and the lumenal depletion domain of an intracellular Ca2+ channel, lumenal and cytosolic Ca2+ profiles are matched to give an implicit analytical expression for the effect of bulk lumenal Ca2+ on [Ca2+]d. PMID:8968577

  17. EQUALIZING THE ELECTRIC FIELD INTENSITY WITHIN CHICK BRAIN IMMERSED IN BUFFER SOLUTION AT DIFFERENT CARRIER FREQUENCIES

    EPA Science Inventory

    Presented here are the numerical relationships between incident power densities that produce the same average electric field intensity within a chick brain half immersed in buffered saline solution and exposed to a uniform electromagnetic field at carrier frequencies of 50, 147, ...

  18. Catalytic Deprotection of Acetals In Strongly Basic Solution Usinga Self-Assembled Supramolecular 'Nanozyme'

    SciTech Connect

    Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

    2007-07-26

    Acetals are among the most commonly used protecting groups for aldehydes and ketones in organic synthesis due to their ease of installation and resistance to cleavage in neutral or basic solution.[1] The common methods for hydrolyzing acetals almost always involve the use of either Broensted acid or Lewis acid catalysts.[2] Usually aqueous acids or organic solutions acidified with organic or inorganic acids have been used for reconversion of the acetal functionality to the corresponding carbonyl group; however, recently a number of reports have documented a variety of strategies for acetal cleavage under mild conditions. These include the use of Lewis acids such as bismuth(III)[3] or cerium(IV),[4, 5] functionalized silica gel, such as silica sulfuric acid[6] or silica-supported pyridinium p-toluene sulfonate,[7] or the use of silicon-based reagents such as TESOTf-2,6-Lutidine.[8] Despite these mild reagents, all of the above conditions require either added acid or overall acidic media. Marko and co-workers recently reported the first example of acetal deprotection under mildly basic conditions using catalytic cerium ammonium nitrate at pH 8 in a water-acetonitrile solution.[5] Also recently, Rao and co-workers described a purely aqueous system at neutral pH for the deprotection of acetals using {beta}-cyclodextrin as the catalyst.[9] Herein, we report the hydrolysis of acetals in strongly basic aqueous solution using a self-assembled supramolecular host as the catalyst. During the last decade, we have used metal-ligand interactions for the formation of well-defined supramolecular assemblies with the stoichiometry M{sub 4}L{sub 6}6 (M = Ga{sup III} (1 refers to K{sub 12}[Ga{sub 4}L{sub 6}]), Al{sup III}, In{sup III}, Fe{sup III}, Ti{sup IV}, or Ge{sup IV}, L = N,N{prime}-bis(2,3-dihydroxybenzoyl)-1,5-diaminonaphthalene) (Figure 1).[10] The metal ions occupy the vertices of the tetrahedron and the bisbidentate catecholamide ligands span the edges. The strong mechanical coupling of the ligands transfers the chirality from one metal center to the other, thereby requiring the {Delta}{Delta}{Delta}{Delta} or {Lambda}{Lambda}{Lambda}{Lambda} configurations of the assembly. While the 12- overall charge imparts water solubility, the naphthalene walls of the assembly provide a hydrophobic environment which is isolated from the bulk aqueous solution. This hydrophobic cavity has been utilized to kinetically stabilize a variety of water-sensitive guests such as tropylium,[11] iminium ions,[12] diazonium ions,[13] and reactive phosphonium species.[14] Furthermore, 1 has been used to encapsulate catalysts[15] for organic transformations as well as act as a catalyst for the 3-aza-Cope rearrangement of enammonium substrates[16] and the hydrolysis of acid-labile orthoformates.[17] Our recent work using 1 as a catalyst for orthoformate hydrolysis prompted our investigation of the ability of 1 to catalyze the deprotection of acetals (Scheme 1). With the ability of 1 to favor encapsulation of monocationic guests, we anticipated that the rates of acetal hydrolysis could be accelerated by stabilization of any of the cationic protonated intermediates along the mechanistic pathway upon encapsulation in 1. In contrast to the stability of 2,2-dimethoxypropane in H{sub 2}O at pH 10, addition of the acetal to a solution of 1 at this pH quickly yielded the products of hydrolysis (acetone and methanol). Addition of a strongly binding inhibitor for the interior cavity of 1, such as NEt{sub 4}{sup +} (log (K{sub a}) = 4.55), inhibited the overall reaction, confirming that 1 is active in the catalysis.

  19. Anglesite (PbSO 4) solubility in acetate solutions: The determination of stability constants for lead acetate complexes to 85°C

    NASA Astrophysics Data System (ADS)

    Giordano, Thomas H.

    1989-02-01

    Anglesite solubilities were determined at 25, 40, 55, 70, and 85°C in solutions with equal molal concentrations of acetic acid and sodium acetate (each ranging from 0.001 to 0.25 m) and at pH values near 4.6. Experiments were conducted using 1000 ml, externally heated glass reaction vessels, and lead concentrations were measured using atomic absorption spectrophotometry. For run conditions with free acetate concentrations less than about 0.01 m, measured a anglesite solubilities are less than or equal to 100 mg/l. Above free acetate concentrations of 0.01 m, measured anglesite solubilities rise sharply to concentrations near 1000 mg/l. Extracted from these solubility data, by a numerical successive linear extrapolation method, were stoichiometries and thermodynamic stability constants (ionic strength = 0) for the complexes Pb(CH 3COO) + and Pb(CH 3COO) 2. Log K1 and log K2 values for the formation reactions Pb + + CH 3COO - = PbCH 3COO + and Pb 2+ + 2CH 3COO - = Pb(CH 3COO) 2 respectively are log K1: (2.4±0.1, 25°C), (2.4±0.1, 40°C), (2.5±0.1, 55°C), (2.6±0.1, 70°C), (2.7±0.2, 85°C) and log K2: (3.4±0.4, 25°C), (3.6±0.2, 40°C), (3.8 ±0.2, 55°C), (4.0±0.2, 70°C), (4.3±0.2, 85°C). Lead hydrolysis was found to be significant in those experiments conducted at 70 and 85°C. However, hydrolyzed lead was not detected at 25, 40, and 55°C. PbOH + as percent of total observed lead ranged from 0.2 to 24% and 2 to 86% in those experiments at 70 and 85°C, respectively. Calculations of lead speciation in acetate solutions show that the equivalence point for PbCH 3COO + and Pb(CH 3COO) 2 shifts to lower acetate concentrations from 25 to 85°C. These speciation calculations also suggest that lead acetate complexes could be significant in high acetate formation waters. These waters typically contain at least 1,000 ppm acetate (0.017 molal as acetic acid). Furthermore, if these waters are not too acid and if concentrations of competing ligands are low, lead acetate complexes should be the dominant lead species.

  20. Effect of acetic NaF solution on the corrosion behavior of stainless steel orthodontic brackets.

    PubMed

    Jang, Hee-Song; Son, Woo-Sung; Park, Soo-Byung; Kim, Hyung-Il; Yong, Hoon Kwon

    2006-06-01

    This study assessed the effect of acetic NaF solutions on stainless steel orthodontic brackets. Acetic acid was added to a 0.1% NaF solution to make two solutions, one with pH 3.5 and the other with pH 6. For the two different stainless steel brackets (Tomy, Dentaurum) used in this study, they had a similar elemental composition--except with Mo (molybdenum) in the Tomy bracket. The brackets were then immersed in the prepared test solutions for three days and their responses evaluated. In terms of hydrofluoric acid (HF) concentration, the 0.1%/pH 3.5 solution showed a high HF concentration at 227 ppm, while that of 0.1%/pH 6 solution was very low at 7 ppm. In terms of color change and element release, only the Dentaurum brackets in 0.1%/pH 3.5 solution showed an appreciable color change (deltaE* = 4.0) and released a great amount of elements (Fe, Cr, Ni, Mn) after three days. Otherwise, regardless of pH value and product, only minor color change (deltaE* < 1.0) and negligible element release occurred. In terms of surface modification, no visible changes in surface morphology were observed in any product after immersion in test solutions. PMID:16916238

  1. Dehydration of ethyl acetate aqueous solution by pervaporation using PVA\\/PAN hollow fiber composite membrane

    Microsoft Academic Search

    Hai-Kuan Yuan; Jie Ren; Xiao-Hua Ma; Zhen-Liang Xu

    2011-01-01

    Using poly(vinyl alcohol) (PVA) as coating material, tartaric acid (Tac) and maleic anhydride (Mac) as cross-linking agents and the poly(acrylonitrile) (PAN) hollow fiber ultrafiltration membrane as support layer, the PVA\\/PAN composite membrane was prepared by dip-coating method used for pervaporation (PV) dehydration of ethyl acetate (EAc)\\/H2O solution. The PVA\\/PAN composite membrane was characterized by FT-IR spectra and SEM. The effects

  2. Anodic oxidation of 3,4-dihydroxyphenylacetic acid on carbon electrodes in acetic acid solutions

    Microsoft Academic Search

    Slawomir Michalkiewicz; Agata Skorupa

    2010-01-01

    The electrochemical oxidation of 3,4-dihydroxyphenylacetic acid (DOPAC) on a carbon fiber microelectrode (CF) and a glassy carbon macroelectrode (GC) in glacial acetic acid solutions was investigated using voltammetric techniques. Voltammograms recorded at these electrodes show well-defined single waves or peaks. The proposed mechanism of the anodic oxidation of DOPAC consists of two successive one-electron one-proton steps. The loss of the

  3. Viscosity Behavior of ?-Amino Acids in Acetate Salt Solutions at Temperatures (303.15 to 323.15) K

    NASA Astrophysics Data System (ADS)

    Siddique, Jamal Akhter; Naqvi, Saeeda

    2012-01-01

    Viscosities of l-lysine monohydrochloride, l-histidine, and l-arginine in 1 m (mol · kg-1) aqueous solutions of sodium acetate, potassium acetate, and calcium acetate salts has been determined at (303.15, 308.15, 313.15, 318.15, and 323.15) K. The Falkenhagen coefficient, A, and Jones-Dole coefficient, B, relative viscosity, and specific viscosity of the solutions have also been determined using the measured viscosities. The results are interpreted in terms of solute-solute and solute-solvent interactions occurring in the system under investigation and also discussed in terms of the structure-making/breaking ability of the solute in these salt solutions. The structure making/breaking abilities of the solutes in the studied systems are strongly influenced by temperature.

  4. Low temperature heteroepitaxy of InP on Si(111) substrates treated with buffered HF solution

    NASA Astrophysics Data System (ADS)

    Ababou, Y.; Masut, R. A.; Yelon, A.; Poulin, S.

    1995-06-01

    Low temperature metalorganic vapor phase heteroepitaxy of InP on Si(111) using buffered HF solutions for preparation of the Si surface is reported. X-ray photoelectron spectroscopy analysis showed no presence of chemisorbed contaminants on the substrate surface after surface preparation. We used high-resolution x-ray diffraction to characterize the quality of the InP epilayers. Optimum InP layers were obtained when the surface was treated with a buffered HF solution with a pH of 6.2, which produces the minimum substrate surface roughness, as reported in the literature. The InP layers grown on normally oriented Si(111) show the presence of large antiphase domains.

  5. The Acid Hydrolysis Mechanism of Acetals Catalyzed by a Supramolecular Assembly in Basic Solution

    SciTech Connect

    Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

    2008-09-24

    A self-assembled supramolecular host catalyzes the hydrolysis of acetals in basic aqueous solution. The mechanism of hydrolysis is consistent with the Michaelis-Menten kinetic model. Further investigation of the rate limiting step of the reaction revealed a negative entropy of activation ({Delta}S{double_dagger} = -9 cal mol{sup -1}K{sup -1}) and an inverse solvent isotope effect (k(H{sub 2}O)/k(D{sub 2}O) = 0.62). These data suggest that the mechanism of hydrolysis that takes place inside the assembly proceeds through an A-2 mechanism, in contrast to the A-1 mechanism operating in the uncatalyzed reaction. Comparison of the rates of acetal hydrolysis in the assembly with the rate of the reaction of unencapsulated substrates reveals rate accelerations of up to 980 over the background reaction for the substrate diethoxymethane.

  6. Radiolysis of aqueous solutions of acetic acid in the presence of Na-montmorillonite

    NASA Technical Reports Server (NTRS)

    Navarro-Gonzalez, R.; Negron-Mendoza, A.; Ramos, S.; Ponnamperuma, C.

    1990-01-01

    The gamma-irradiation of 0.8 mol dm-3 aqueous, oxygen-free acetic acid solutions was investigated in the presence or absence of Na-montmorillonite. H2, CH4, CO, CO2, and several polycarboxylic acids were formed in all systems. The primary characteristics observed in the latter system were: (1) Higher yield of the decomposition of acetic acid; (2) Lower yield of the formation of polycarboxylic acids; (3) No effect on the formation of methane; (4) Higher yield of the formation of carbon dioxide; and (5) The reduction of Fe3+ in the octahedral sites of Na-montmorillonite. A possible reaction scheme was proposed to account for the observed changes. The results are important in understanding heterogeneous processes in radiation catalysis and might be significant to prebiotic chemistry.

  7. Evaluation of prolonged exposure of lacquered tinplate cans to a citrate buffer solution using electrochemical techniques

    Microsoft Academic Search

    J. M. Bastidas; J. M. Cabañes; R. Catalá

    1997-01-01

    Four lots of tinplate cans, internally coated with water- and organic solvent-based epoxyphenolic lacquer, were studied. A 0.1 M citric-citrate test buffer solution (pH 3.5) was packed at 90 °C, sterilised at 121 °C and stored at room temperature. A full opened can was used as the working electrode and electrolytic cell. Electrochemical a.c. and d.c. experiments were conducted after

  8. Novel nutrient solutions for zinc nutrition research: buffering free zinc 2+ with synthetic chelators and P with hydroxyapatite

    Microsoft Academic Search

    David R. Parker

    1993-01-01

    Chelator-buffered nutrient solutions, in which computed free Zn2+ activities are buffered at =10-10.0M by including an excess of a synthetic chelator such as EDTA, have recently shown promise as a means of precisely regulating Zn nutritional status. A further refinement that would eliminate the confounding effect of high (and often phytotoxic) shoot P concentrations in solution-grown, Zn-deficient plants is also

  9. Biomimetic oxidation of indole-3-acetic acid and related substrates with hydrogen peroxide catalysed by 5,10,15,20-tetrakis 2?,6?-dichloro-3?-sulfonatophenyl)porphyrinatoiron(III) hydrate in aqueous solution and AOT reverse micelles

    Microsoft Academic Search

    S. M. S. Chauhan; P. P. Mohapatra; Bhanu Kalra; T. S. Kohli; S. Satapathy

    1996-01-01

    The reaction of indole-3-acetic acid (IAA) with hydrogen peroxide catalysed by 5,10,15,20-tetrakis(2?,6?-dichloro-3?-sulfonatophenyl)porphyrinatoiron(III)hydrate [Cl8TPPS4Fe(III)(OH2)2] gives indole-3-carbinol (IC) and indole-3-carboxaldehyde (IA) in aqueous buffer solution. The oxidation of IAA with H2O2 in the presence of Cl8TPPS4Fe(III)(OH2)2 in AOT reverse micelles gives higher yields of IA than in aqueous solution at the same pH. The yields of different oxidation products in AOT reverse

  10. Nonclinical safety evaluation of boric acid and a novel borate-buffered contact lens multi-purpose solution, Biotrue™ multi-purpose solution

    Microsoft Academic Search

    David M. Lehmann; Megan E. Cavet; Mary E. Richardson

    Multipurpose solutions (MPS) often contain low concentrations of boric acid as a buffering agent. Limited published literature has suggested that boric acid and borate-buffered MPS may alter the corneal epithelium; an effect attributed to cytotoxicity induced by boric acid. However, this claim has not been substantiated. We investigated the effect of treating cells with relevant concentrations of boric acid using

  11. Hydrolysis of chlorantraniliprole and cyantraniliprole in various pH buffer solutions.

    PubMed

    Sharma, Ashok K; Zimmerman, William T; Lowrie, Chris; Chapleo, Simon

    2014-04-23

    The hydrolysis reactions of [(14)C]-chlorantraniliprole (CLAP) and cyantraniliprole (CNAP) were investigated in sterile buffer solutions at pH 4, 7, and 9. Both compounds displayed similar degradation reactions. The reactions observed were intramolecular cyclizations and rearrangements instead of the anticipated amide hydrolysis to carboxylic acids. Despite a minor difference in their structures, the degradation rates for the two compounds were substantially different. The reaction rates were examined at multiple temperatures to understand the mechanistic aspects of the underlying transformations. Similarities and differences in the hydrolysis behavior of these compounds in various pH values and temperatures are described. PMID:24694259

  12. Electrospinning of chitosan solutions in acetic acid with poly(ethylene oxide).

    PubMed

    Duan, Bin; Dong, Cunhai; Yuan, Xiaoyan; Yao, Kangde

    2004-01-01

    Electrospinning of chitosan solutions with poly(ethylene oxide) (PEO) in an aqueous solution of 2 wt% acetic acid was studied. The properties of the chitosan/PEO solutions, including conductivity, surface tension and viscosity, were measured. Morphology of the electrospun chitosan/PEO was observed by using scanning electron micrographs. Results showed that the ultrafine fibers could be generated after addition of PEO in 2:1 or 1:1 mass ratios of chitosan to PEO from 4-6 wt% chitosan/PEO solutions at 15 kV voltage, 20 cm capillary-collector distance and flow rate 0.1 ml/h. During electrospinning of the chitosan/PEO solutions, ultrafine fibers with diameters from 80 nm to 180 nm were obtained, while microfibers with visually thicker diameters could be formed as well. Results of X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and differential scanning calorimeter exhibited the larger electrospun microfibers were almost entirely made from PEO, while the electrospun ultrafine fibers mainly contained chitosan. PMID:15255527

  13. Characteristics of thin cellulose ester films spin-coated from acetone and ethyl acetate solutions

    Microsoft Academic Search

    J. Amim Jr; P. M. Kosaka; D. F. S. Petri

    2008-01-01

    Spin-coated films of cellulose acetate (CA), cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB) and carboxymethylcellulose\\u000a acetate butyrate (CMCAB) have been characterized by ellipsometry, atomic force microscopy (AFM) and contact angle measurements.\\u000a The films were spin-coated onto silicon wafers, a polar surface. Mean thickness values were determined by means of ellipsometry\\u000a and AFM as a function of polymer concentration in

  14. Production of ethyl acetate from dilute ethanol solutions by Candida utilis

    Microsoft Academic Search

    David W. Armstrong; Stanley M. Martin; Hiroshi Yamazaki

    1984-01-01

    The conversion of ethanol to ethyl acetate has an advantage as a method of ethanol recovery since ethyl acetate is amenable to simple solvent extraction. The potential of Candida utilis in this conversion was studied. The kinetics of accumulation of ethanol and ethyl acetate in glucose-grown C. utilis showed that ester formation resulted from ethanol utilization under appropriate aeration and

  15. Advantage of buffered solutions or automated capnometry in air-filled balloons for use in gastric tonometry

    Microsoft Academic Search

    B. Temmesfeld-Wollbrück; A. Szalay; H. Olschewski; F. Grimminger; W. Seeger

    1997-01-01

    Objective: To test accuracy, reproducibility and time constants of pCO2 measurement with the tonometric technique, using different media for filling the silastic balloon (saline, phosphate buffer,\\u000a citrate buffer, air) and employing different analyzer devices (ABL3, ABL330, Nova Stat 5, automated capnometry). Design: Comparative laboratory study of different tonometric techniques, measuring test solutions with known pCO2 values due to pre-equilibration with

  16. Development of Solution Buffer Layers for RABiTS Based YBCO Coated Conductors

    SciTech Connect

    Paranthaman, Mariappan Parans [ORNL; Qiu, Xiaofeng [ORNL; Kim, Kyunghoon [ORNL; Shi, D. [University of Cincinnati; Zhang, Yifei [ORNL; Li, Xiaoping [American Superconductor Corporation, Westborough, MA; Sathyamurthy, Srivatsan [ORNL; Thieme, C. L. H. [American Superconductor Corporation, Westborough, MA; Rupich, M. W. [American Superconductor Corporation, Westborough, MA

    2010-01-01

    The main objective of this research is to find a suitable alternate solution based seed layer for the standard RABiTS three-layer architecture of physical vapor deposited CeO2 cap/YSZ barrier/Y2O3 seed on Ni-5%W metal tape. In the present work, we have identified CeO2 buffer layer as a potential replacement for Y2O3 seeds. Using a metal-organic deposition (MOD) process, we have grown smooth, crack-free, epitaxial thin films of CeO2 (both pure and Zr, Cu and Gd-doped) directly on biaxially textured Ni-5W substrates in short lengths. Detailed XRD studies indicate that a single epitaxial CeO2 phase with slightly improved out-of-plane texture compared to the texture of underlying Ni-W substrates can be achieved in pure, undoped CeO2 samples. We have also demonstrated the growth of YSZ barrier layers on pure CeO2 seeds using sputtering. Both sputtered CeO2 cap layers and MOD-YBCO films were grown epitaxially on these YSZ-buffered MOD-CeO2/Ni-5W substrates. High critical currents per unit width, Ic of 264 A/cm (critical current density, Jc of 3.3 MA/cm2) at 77 K and 0.01 T was achieved for 0.8 m thick MOD-YBCO films grown on MOD-CeO2 seeds. These results indicate that CeO2 films can be grown directly on Ni-5W substrates and still support high performance YBCO coated conductors. This work holds promise for a route for producing low-cost buffer architecture for RABiTS based YBCO coated conductors.

  17. Development of Solution Buffer Layers for RABiTS Based YBCO Coated Conductors

    SciTech Connect

    Paranthaman, Mariappan Parans [ORNL; Qiu, Xiaofeng [ORNL; List III, Frederick Alyious [ORNL; Zhang, Yifei [ORNL; Li, Xiaoping [American Superconductor Corporation, Westborough, MA; Sathyamurthy, Srivatsan [ORNL; Thieme, C. L. H. [American Superconductor Corporation, Westborough, MA; Rupich, M. W. [American Superconductor Corporation, Westborough, MA

    2011-01-01

    Abstract The main objective of this research is to find a suitable alternate solution based seed layer for the standard RABiTS three-layer architecture of physical vapor deposited CeO cap/YSZ barrier/Y O seed on Ni-5%W metal tape. In the present work, we have identified CeO buffer layer as a potential replacement for Y O seeds. Using a metal-organic deposition (MOD) process, we have grown smooth, crack-free, epitaxial thin films of CeO (pure and Zr, Cu and Gd-doped) directly on biaxially textured Ni-5W substrates in short lengths. Detailed XRD studies indicate that a single epitaxial CeO phase with slightly improved out-of-plane texture compared to the texture of the underlying Ni-W substrates can be achieved in pure, undoped CeO samples. We have also demonstrated the growth of YSZ barrier layers on pure CeO seeds using sputtering. Both sputtered CeO cap layers and MOD-YBCO films were grown epitaxially on these YSZ-buffered MOD-CeO /Ni-5W substrates. High critical currents per unit width, of 264 A/cm (critical current density, of 3.3 MA/cm ) at 77 K and 0.01 T was achieved for 0.8 m thick MOD-YBCO films grown on MOD-CeO seeds. These results indicate that CeO films can be grown directly on Ni-5W substrates and still support high performance YBCO coated conductors. This work holds promise for a route for producing low-cost buffer architecture for RABiTS based YBCO coated conductors.

  18. 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...

  19. A study of the copper electrode behavior in borax buffer solutions containing chloride ions and benzotriazole-type inhibitors by voltammetry and the photocurrent response method

    Microsoft Academic Search

    Guo-Ding Zhou; Hua Shao; B. H. Loo

    1997-01-01

    The electrochemical behavior of the Cu electrode in borax buffer solutions containing chloride ions and benzotriazole (BTA)-type inhibitors was studied by voltammetry and the photocurrent response method. A p-type photoresponse was observed from the Cu electrode in the pure borax buffer solutions. However, an n-type photoresponse was observed in chloride-containing borax buffer solutions if the Cl? concentration exceeded 0.08%. The

  20. Electrophoresis Buffers And Solutions Use ACS grade chemicals and dH2O for all buffers.

    E-print Network

    Aris, John P.

    % Acrylamide Solution For SDS-PAGE: 200 ml 60 g Acrylamide 1.6 g Methylene Bis acrylamide (1:37.5) Bring to 200 27.5 g Boric Acid 3.72 g Na2EDTA-2dH2O (ultrapure) 40% Acrylamide Stock Solution For Nucleic Acid Gels: 200ml 76 g Acrylamide 4 g Methylene Bis acrylamide (1:19) Bring to 200 ml with dH2O. Store at 4°C

  1. Sol-gel preparation of ZnO films with extremely preferred orientation along (002) plane from zinc acetate solution

    Microsoft Academic Search

    Masashi Ohyama; Hiromitsu Kouzuka; Toshinobu Yoko

    1997-01-01

    ZnO films with preferred orientation along the (002) plane were fabricated by the sol-gel method using Zn(CH3COO)2 · 2H2O as starting material. A homogeneous and stable solution was prepared by dissolving the zinc acetate in a solution of 2-methoxyethanol and monoethanolamine. ZnO films highly oriented along the (002) plane were obtained by preheating the dip-coating films at temperatures from 200°

  2. Growth of layered basic zinc acetate in methanolic solutions and its pyrolytic transformation into porous zinc oxide films.

    PubMed

    Hosono, Eiji; Fujihara, Shinobu; Kimura, Toshio; Imai, Hiroaki

    2004-04-15

    Layered basic zinc acetate (LBZA), Zn(5)(OH)(8)(CH(3)COO)(2).2H(2)O, was deposited on glass substrates by a chemical bath deposition (CBD) method using methanolic solutions of zinc acetate dihydrate. The substrates were put into bottles filled with the solutions and sealed up and were kept at 60 degrees C in a drying oven. Immersion time necessary for the deposition of LBZA films was typically more than 28 h. This was a key to inducing heterogeneous nucleation of LBZA through control over a degree of supersaturation in the evolution of a unique, nest-like morphology. Hydration water contained by zinc acetate dihydrate was quantitatively enough to promote hydrolysis of zinc acetate. The LBZA films were transformed into nanocrystalline, porous ZnO films without morphological deformation by heating at 150 degrees C in air. A mechanism of the formation of the nest-like morphology was discussed based on nonaqueous solution reactions, nucleation, and crystal growth during the CBD process. PMID:15028503

  3. Production of ethyl acetate from dilute ethanol solutions by Candida utilis

    SciTech Connect

    Armstrong, D.W.; Martin, S.M.; Yamazaki, H.

    1984-01-01

    The conversion of ethanol to ethyl acetate has an advantage as a method of ethanol recovery since ethyl acetate is amenable to simple solvent extraction. The potential of Candida utilis in this conversion was studied. The kinetics of accumulation of ethanol and ethyl acetate in glucose-grown C. utilis showed that ester formation resulted from ethanol utilization under appropriate aeration and was inhibited by Fe/sup 3 +/ supplementation. Candida utilis converted ethanol to ethyl acetate optimally at pH 5.0-7.0. The five-hour rate of ester production increased as the ethanol concentration increased to 10 g/L, and rapidly declined to zero at concentrations exceeding 35 g/L. Thus, C. utilis has potential to recover dilute ethanol in the form of ethyl acetate.

  4. Structural and optical characterizations of ZnO aerogel nanopowder synthesized from zinc acetate ethanolic solution

    NASA Astrophysics Data System (ADS)

    Djouadi, D.; Meddouri, M.; Chelouche, A.

    2014-11-01

    ZnO aerogel powder has been synthesized by a modified sol-gel process using zinc acetate ethanolic solution. XRD, SEM, EDAX, FTIR, UV-visible absorption and photoluminescence (PL) techniques have been used to characterize the as-prepared and the annealed ZnO aerogel powders. The as-prepared ZnO powder has a well-defined polycrystalline hexagonal wurtzite structure. This measurement has demonstrated that the lattice parameters are lower than the standard ones indicating that drying in supercritical conditions of ethanol does not affect the crystallinity but acts as a compressive agent. EDAX measurements show that the obtained aerogel contains only O and Zn elements. Annealing improves the crystallinity in the low DRX angles and decreases the crystalline quality in the high diffraction angles. Also, annealing acts as a tensile agent and increases the lattice parameters. FTIR spectra confirm the annealing effect by the apparition of the strong Zn-O vibration band. The ZnO absorption band shifts to lower wave numbers after annealing indicating an increase in the Zn-O bond length and confirms the XRD results. UV-visible results show a decrease of the ZnO aerogel optical band gap after annealing and confirm the thermal decompression effect on the lattice parameters. The photoluminescence measurements show that the annealing of ZnO aerogel favors the thermal generation of zinc interstitials and oxygen vacancies defects existing in the as-prepared zinc oxide aerogel and shifts the emission toward lower energies.

  5. Toxicological study of a glucose-added acetic acid maintenance infusion solution (VEEN 3G Inj.) local irritation test.

    PubMed

    Onodera, K; Kawaguch, M; Shibata, M; Kagawa, M; Kojima, J; Shimizu, K; Yoneko, M; Wachi, M

    2002-01-01

    The local irritating effect of Veen 3G Inj. (glucose-added acetic acid maintenance infusion solution) was examined in male rabbits. We studied the local irritating effect of the infusion solution compared with that of Ringer's solution, 5% sulfobromophthalein sodium injection, distilled water for injection or glucose-added Ringer's solution. In the vascular irritation test, macroscopical and histopathological changes induced by the infusion solution were not observed in the vessels. Moreover, in the hemolytic test, hemolysis of rabbit erythrocyte was not observed in the mixture with the infusion solution. In the present study, no change suggesting irritation by the infusion solution was observed in the in vivo vascular irritation test using the auricular vein of rabbits or in the in vitro hemolytic test using rabbit erythrocyte. In conclusion, in clinical use the infusion solution produces extremely slight adverse effects, such as vessel pain and phlebitis on the injection site. PMID:12073764

  6. PHOSPHORUS AND ZINC INTERACTIONS AND THEIR RELATIONSHIPS WITH OTHER NUTRIENTS IN MAIZE GROWN IN CHELATOR-BUFFERED NUTRIENT SOLUTION

    Microsoft Academic Search

    Brandt A. Nichols; Bryan G. Hopkins; Von D. Jolley; Bruce L. Webb; Bryan G. Greenwood; Joshua R. Buck

    2012-01-01

    Maize (Zea mays L.) is common in potato (Solanum tuberosum L.) cropping systems and is especially susceptible to zinc (Zn) deficiency, possibly related to induced potato demand for high phosphorus (P). Three chelator-buffered nutrient solution experiments were evaluated for maize response to establish ranges of deficient, sufficient, and excessive Zn and P and to evaluate interactions. Zinc concentrated in roots

  7. Determination of bromide ions in seawater by capillary zone electrophoresis using diluted artificial seawater as the buffer solution

    Microsoft Academic Search

    Keiichi Fukushi; Keisuke Watanabe; Sahori Takeda; Shin-Ichi Wakida; Masataka Yamane; Kunishige Higashi; Kazuo Hiiro

    1998-01-01

    A novel capillary zone electrophoresis method was developed for the determination of bromide ion in seawater. A tenfold-diluted artificial seawater was adopted as the buffer solution, to prevent interference from high concentrations of chloride ion in seawater. No electroosmotic flow reverser was used to shorten the analysis time. It was found that the peak area and migration time for bromide

  8. Zinc-phosphorus interactions in two cultivars of tomato ( Lycopersicon esculentum L.) grown in chelator-buffered nutrient solutions

    Microsoft Academic Search

    D. R. Parker; J. J. Aguilera; D. N. Thomason

    1992-01-01

    Zinc-phosphorus interactions have been frequently studied using a diverse number of crop species, but attainment of reproducible Zn deficiencies, especially severe ones, has been hampered by the use of conventional hydroponic solutions wherein contaminating levels of Zn are often near-adequate for normal growth. We utilized novel, chelator-buffered nutrient solutions for precise imposition of Zn deficiencies. Tomato (Lycopersicon esculentum L. cv.

  9. Enhancement of the absorption of CO{sub 2} in alkaline buffer solutions: Joint action of two enhancers

    SciTech Connect

    Vazquez, G.; Chenlo, F.; Pereira, G.; Vazquez, P. [Univ. of Santiago de Compostela (Spain). Dept. of Chemical Engineering] [Univ. of Santiago de Compostela (Spain). Dept. of Chemical Engineering

    1999-05-01

    The authors measured the absorption of CO{sub 2} in alkaline 0.5 M/0.5 M sodium carbonate/bicarbonate buffers containing either saccharose and sodium arsenite or saccharose and formaldehyde. Absorption enhancement increased upon increasing the concentration of either of the catalysts, but the joint action of the two was always less than the sum of their individual effects, the difference being a function of the acidities and concentrations of the catalysts and the pH of the carbonate/bicarbonate buffer solution

  10. Plasma acetate, gluconate and interleukin-6 profiles during and after cardiopulmonary bypass: a comparison of Plasma-Lyte 148 with a bicarbonate-balanced solution

    Microsoft Academic Search

    Paul G Davies; Balasubramanian Venkatesh; Thomas J Morgan; Jeffrey J Presneill; Peter S Kruger; Bronwyn J Thomas; Michael S Roberts; Julie Mundy

    2011-01-01

    INTRODUCTION: As even small concentrations of acetate in the plasma result in pro-inflammatory and cardiotoxic effects, it has been removed from renal replacement fluids. However, Plasma-Lyte 148 (Plasma-Lyte), an electrolyte replacement solution containing acetate plus gluconate is a common circuit prime for cardio-pulmonary bypass (CPB). No published data exist on the peak plasma acetate and gluconate concentrations resulting from the

  11. Structural Characterization of Apomyoglobin Self-Associated Species in Aqueous Buffer and Urea Solution

    PubMed Central

    Chow, Charles; Kurt, Ne?e; Murphy, Regina M.; Cavagnero, Silvia

    2006-01-01

    The biophysical characterization of nonfunctional protein aggregates at physiologically relevant temperatures is much needed to gain deeper insights into the kinetic and thermodynamic relationships between protein folding and misfolding. Dynamic and static laser light scattering have been employed for the detection and detailed characterization of apomyoglobin (apoMb) soluble aggregates populated at room temperature upon dissolving the purified protein in buffer at pH 6.0, both in the presence and absence of high concentrations of urea. Unlike the ?-sheet self-associated aggregates previously reported for this protein at high temperatures, the soluble aggregates detected here have either ?-helical or random coil secondary structure, depending on solvent and solution conditions. Hydrodynamic diameters range from 80 to 130 nm, with semiflexible chain-like morphology. The combined use of low pH and high urea concentration leads to structural unfolding and complete elimination of the large aggregates. Even upon starting from this virtually monomeric unfolded state, however, protein refolding leads to the formation of severely self-associated species with native-like secondary structure. Under these conditions, kinetic apoMb refolding proceeds via two parallel routes: one leading to native monomer, and the other leading to a misfolded and heavily self-associated state bearing native-like secondary structure. PMID:16214860

  12. Decontamination of aquatic vegetable leaves by removing trace toxic metals during pickling process with acetic acid solution.

    PubMed

    Wu, Wenbiao; Yang, Yixing

    2011-01-01

    The heavy-metal content of aquatic plants is mainly dependent upon their ecological system. This study indicated that although the toxic heavy-metal contents could be above the recommended maximum levels depending upon their concentrations in growing water, they can be decontaminated by pickling with 5% acetic acid solution. Almost all Cd, Hg, Ba, or Sb and 99.5% Pb, 96.7% Ag, or 97.1% Al were removed from Water Spinach leaves by soaking in acetic acid solution. For Water-Shield leaves, almost all Cd, Hg, Pb, Ba, or Sb and 95.0% Ag or 96.1% Al were removed. For Watercress leaves, almost all Cd, Hg, Ba, or Sb and 99.0% Pb or 99.7% Ag were removed. For Water Hyacinth leaves, almost all Cd, Ba, or Sb and 99.0% Hg, 98.5% Pb, 95.0% Ag, or 98.7% Al were removed. PMID:21888602

  13. Adsorption of Cu 2+ and Cd 2+ from aqueous solution by mercapto-acetic acid modified orange peel

    Microsoft Academic Search

    Liang Sha; Guo Xueyi; Feng Ningchuan; Tian Qinghua

    2009-01-01

    The present article describes the adsorption behaviors of Cu2+ and Cd2+ on mercapto-acetic acid modified orange peel. The prepared adsorbents were characterized using Malvern Zetasizer, infrared spectrophotometer and infrared C–S analyzer. The effect of various parameters like solution pH, contact time, and initial metal ion concentration on adsorption efficiencies of these two metals were studied systematically by batch experiments. Adsorption

  14. Cross-linked HTPB-based polyurethaneurea membranes for recovery of ethyl acetate from aqueous solution by pervaporation

    Microsoft Academic Search

    Yunxiang Bai; Jinwen Qian; Chunfang Zhang; Lin Zhang; Quanfu An; Huanlin Chen

    2008-01-01

    Cross-linked hydroxy terminated polybutadiene (HTPB)-based polyurethaneurea (PU), HTPB–DVB–PU, was synthesized by a three-step polymerization process. It was firstly used as membrane material to recover aroma, ethyl acetate (EA), from aqueous solution by pervaporation (PV). The effects of the content of cross-linker DVB, EA concentration in feed, and operating temperature on the PV performance of HTPB–DVB–PU membranes were investigated. The membranes

  15. Habit changes of NaBrO 3 crystals grown from aqueous solution doped with sodium acetate

    Microsoft Academic Search

    Masayo Sone; Tetsuo Inoue; Shin-ichiro Yanagiya; Atsushi Mori

    2002-01-01

    The effects of doping of sodium acetate upon the habit changes of NaBrO3 crystals have been investigated. The crystals were grown from aqueous solution under the following conditions: (i) supersaturations, ln(C\\/Ce)=0–0.4, (Ce: equilibrium mol fraction); (ii) growth temperatures, 15–43°C. The gross morphologies of crystals have taken on three distinct forms: tetrahedral {111} habit, cubic {100} and intermediate ({111}+{100}) habits. The

  16. Enhanced efficiency of inverted polymer solar cells by using solution-processed TiOx/CsOx cathode buffer layer

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaodong; Fan, Xi; Sun, Xianke; Zhang, Yunli; Zhu, Ziqiang

    2015-01-01

    In this work, a double-buffer film of TiOx coated with CsOx (TiOx/CsOx) was solution prepared to be applied in poly(3-hexylthiophene):indene-C60 bisadduct (P3HT:ICBA) and P3HT:[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) inverted polymer solar cells (PSCs). Compared with TiOx films and CsOx films, the TiOx/CsOx double-buffer film exhibited a favorable energy-level alignment among TiOx, CsOx, and the electron acceptor of PCBM or ICBA a better surface morphology; and an enhanced wetting and adhesion property with a contact angle of 21.0°, leading to a higher electron mobility of 5.52 × 10-3 cm2 V-1·s-1. Moreover, the P3HT:ICBA and P3HT:PCBM photovoltaic devices with the double-buffer film showed the best power conversion efficiency up to 5.65% and 3.76%, respectively. Our results not only present that the double-buffer film is superior than the single film of TiOx and CsOx, but also imply that the solution-processed film has a potential to be generally used in roll-to-roll processed organic photovoltaic devices.

  17. Improving impurities clearance by amino acids addition to buffer solutions for chromatographic purifications of monoclonal antibodies.

    PubMed

    Ishihara, Takashi; Hosono, Mareto

    2015-07-15

    The performance of amino acids in Protein A affinity chromatography, anion exchange chromatography and cation exchange chromatography for monoclonal antibody purification was investigated. Glycine, threonine, arginine, glutamate, and histidine were used as buffer components in the equilibration, washing, and elution steps of these chromatographies. Improved clearance of impurity, high molecular weight species (HMW) and host cell proteins (HCP) was observed in the purification processes when using the amino acids as base-buffer constituents, additives or eluents compared with that of buffers without these amino acids. In addition, we designed a buffer system in which the mobile phases were composed of only a single amino acid, histidine, and applied it to the above three chromatographies. Effective HMW and HCP clearance was also obtained in this manner. These results suggest that amino acids may enhance impurity clearance during the purification of monoclonal antibodies. PMID:26057847

  18. The effect of acetate concentration, solution pH and conductivity on the anodic stripping voltammetry of lead and cadmium ions at in situ bismuth-plated carbon microelectrodes

    Microsoft Academic Search

    L. Baldrianova; P. Agrafiotou; I. Svancara; A. D. Jannakoudakis; S. Sotiropoulos

    2011-01-01

    The use of carbon microdisc electrode substrates allowed Pb(II) and Cd(II) anodic stripping voltammetry at in situ plated bismuth films to be studied in an extended acetate buffer\\/electrolyte concentration range that includes very low or zero acetate levels. The change of the Pb and Cd Square Wave Anodic Stripping Voltammetry (SWASV) peak height with acetate concentration, pH and conductivity has

  19. A study of the behavior of copper electrodes in buffered borax solutions containing BTA-type inhibitors by photoelectrochemical methods

    Microsoft Academic Search

    Qun-jie Xu; Guo-ding Zhou

    2008-01-01

    Purpose – The purpose of this paper is to provide useful information pertaining to the corrosion inhibition mechanism of BTA and its derivatives on copper. Design\\/methodology\\/approach – The photoelectrochemical behavior of copper electrodes in buffered borax solutions (pH 9.2) containing BTA and its derivatives was comparatively studied by using a photoelectrochemical technique. It was possible to analyze the inhibition mechanism

  20. Stabilizing effect of citrate buffer on the photolysis of riboflavin in aqueous solution.

    PubMed

    Ahmad, Iqbal; Sheraz, Muhammad Ali; Ahmed, Sofia; Kazi, Sadia Hafeez; Mirza, Tania; Aminuddin, Mohammad

    2011-05-01

    In the present investigation the photolysis of riboflavin (RF) in the presence of citrate species at pH 4.0-7.0 has been studied. A specific multicomponent spectrophotometric method has been used to assay RF in the presence of photoproducts during the reactions. The overall first-order rate constants (k obs ) for the photolysis of RF range from 0.42 to 1.08×10(-2) min(-1) in the region. The values of k obs have been found to decrease with an increase in citrate concentration indicating an inhibitory effect of these species on the rate of reaction. The second-order rate constants for the interaction of RF with total citrate species causing inhibition range from 1.79 to 5.65×10(-3) M(-1) min(-1) at pH 4.0-7.0. The log k-pH profiles for the reactions at 0.2-1.0 M citrate concentration show a gradual decrease in k obs and the value at 1.0 M is more than half compared to that of k 0, i.e., in the absence of buffer, at pH 5.0. Divalent citrate ions cause a decrease in RF fluorescence due to the quenching of the excited singlet state resulting in a decrease in the rate of reaction and consequently leading to the stabilization of RF solutions. The greater quenching of fluorescence at pH 4.0 compared to that of 7.0 is in accordance with the greater concentration of divalent citrate ions (99.6%) at that pH. The trivalent citrate ions exert a greater inhibitory effect on the rate of RF photolysis compared to that of the divalent citrate ions probably as a result of excited triplet state quenching. The values of second-order rate constants for the interaction of divalent and trivalent citrate ions are 0.44×10(-2) and 1.06×10(-3) M(-1) min(-1), respectively, indicating that the trivalent ions exert a greater stabilizing effect, compared to the divalent ions, on RF solutions. PMID:25755977

  1. Efficient quantum dot light-emitting diodes with solution-processable molybdenum oxide as the anode buffer layer.

    PubMed

    He, Shaojian; Li, Shusheng; Wang, Fuzhi; Wang, Andrew Y; Lin, Jun; Tan, Zhan'ao

    2013-05-01

    Quantum dot light-emitting diodes (QD-LEDs) are characterized by pure and saturated emission colors with narrow bandwidth. Optimization of the device interface is an effective way to achieve stable and high-performance QD-LEDs. Here we utilized solution-processed molybdenum oxide (MoOx) as the anode buffer layer on ITO to build efficient QD-LEDs. Using MoOx as the anode buffer layer provides the QD-LED with good Ohmic contact and a small charge transfer resistance. The device luminance is nearly independent of the thickness of the MoOx anode buffer layer. The QD-LEDs with a MoOx anode buffer layer exhibit a maximum luminance and luminous efficiency of 5230 cd m(-2) and 0.67 cd A(-1) for the yellow emission at 580 nm, and 7842 cd m(-2) and 1.49 cd A(-1) for the red emission at 610 nm, respectively. PMID:23558319

  2. The Effect of Crystallizing and Non-crystallizing Cosolutes on Succinate Buffer Crystallization and the Consequent pH Shift in Frozen Solutions

    SciTech Connect

    Sundaramurthi, Prakash; Suryanarayanan, Raj (UMM)

    2011-09-06

    To effectively inhibit succinate buffer crystallization and the consequent pH changes in frozen solutions. Using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD), the crystallization behavior of succinate buffer in the presence of either (i) a crystallizing (glycine, mannitol, trehalose) or (ii) a non-crystallizing cosolute (sucrose) was evaluated. Aqueous succinate buffer solutions, 50 or 200 mM, at pH values 4.0 or 6.0 were cooled from room temperature to -25 C at 0.5 C/min. The pH of the solution was measured as a function of temperature using a probe designed to function at low temperatures. The final lyophiles prepared from these solutions were characterized using synchrotron radiation. When the succinic acid solution buffered to pH 4.0, in the absence of a cosolute, was cooled, there was a pronounced shift in the freeze-concentrate pH. Glycine and mannitol, which have a tendency to crystallize in frozen solutions, remained amorphous when the initial pH was 6.0. Under this condition, they also inhibited buffer crystallization and prevented pH change. At pH 4.0 (50 mM initial concentration), glycine and mannitol crystallized and did not prevent pH change in frozen solutions. While sucrose, a non-crystallizing cosolute, did not completely prevent buffer crystallization, the extent of crystallization was reduced. Sucrose decomposition, based on XRD peaks attributable to {beta}-D-glucose, was observed in frozen buffer solutions with an initial pH of 4.0. Trehalose completely inhibited crystallization of the buffer components when the initial pH was 6.0 but not at pH 4.0. At the lower pH, the crystallization of both trehalose dihydrate and buffer components was evident. When retained amorphous, sucrose and trehalose effectively inhibited succinate buffer component crystallization and the consequent pH shift. However, when trehalose crystallized or sucrose degraded to yield a crystalline decomposition product, crystallization of buffer was observed. Similarly, glycine and mannitol, two widely used bulking agents, inhibited buffer component crystallization only when retained amorphous. In addition to stabilizing the active pharmaceutical ingredient, lyoprotectants may prevent solution pH shift by inhibiting buffer crystallization.

  3. Removal of dicyclohexyl acetic acid from aqueous solution using ultrasound, ozone and their combination.

    PubMed

    Kumar, Pardeep; Headley, John; Peru, Kerry; Bailey, Jon; Dalai, Ajay

    2014-01-01

    Naphthenic acids are a complex mixture of organic components, some of which include saturated alkyl-substituted cycloaliphatic carboxylic acids and acyclic aliphatic acids. They are naturally found in hydrocarbon deposits like oil sand, petroleum, bitumen and crude oil. In this study, the oxidation of a relatively high molecular weight naphthenic acid (Dicyclohexyl acetic acid) was investigated using ozonation, ultrasonication and hydrogen peroxide alone and their combinations. Effects on oxidation of dicyclohexyl acetic acid (DAA) were measured for different concentrations of ozone ranging between 0.7 to 3.3 mg L(-1) and pH in the range 6 to 10. Ultrasonication and hydrogen peroxide alone were not effective to oxidize dicyclohexyl acetic acid, but combining ultrasonication with H2O2 had a significant effect on oxidation of dicyclohexyl acetic acid with maximum removal reaching to 84 ± 2.2% with 81 ± 2.1% reduction in chemical oxygen demand (COD). Synergistic effects were observed for combining ultrasonication with ozonation and resulted in 100% DAA removal with 98 ± 0.8% reduction in COD within 15 min at 3.3 mg L(-1) ozone concentration and 130 Watts ultrasonication power. The reaction conditions obtained for the maximum oxidation of DAA and COD removal were used for the degradation of naphthenic acids mixture extracted from oil sands process water (OSPW). The percentage oxidation of NAs mixture extracted from OSPW was 89.3 ± 1.1% in ozonation and combined ozonation and ultrasonication, but COD removal observed was 65 ± 1.2% and 78 ± 1.4% for ozonation and combined ozonation and ultrasonication treatments, respectively. PMID:25137539

  4. Fabrication of a solution-processed thin-film transistor using zinc oxide nanoparticles and zinc acetate

    NASA Astrophysics Data System (ADS)

    Lee, Sul; Jeong, Sunho; Kim, Dongjo; Park, Bong Kyun; Moon, Jooho

    2007-07-01

    We have fabricated a solution-processed ZnO thin-film transistor without vacuum deposition. ZnO nanoparticles were prepared by the polyol method from zinc acetate, polyvinyl pyrrolidone, and diethyleneglycol. The solution-processable semiconductor ink was prepared by dispersing the synthesized ZnO in a solvent. Inverted stagger type thin-film transistors were fabricated by spin casting the ZnO ink on the heavily doped Si wafer with 200 nm thick SiO 2, followed by evaporation of Cr/Au source and drain electrodes. After the drying and heat treatment at 600 ?C, a relatively dense ZnO film was obtained. The film characteristics were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). In order to obtain the electrical properties of the solution-derived transistor, the on-off ratio, threshold voltage, and mobility were measured.

  5. Functionalization of carbon nanotubes with proteins and quantum dots in aqueous buffer solutions

    E-print Network

    Falvo, Michael

    , they are not soluble in aqueous buffers. Through noncovalent functionalization with 1-pbase, the MWCNT are stably suspended for a period on the order of weeks. The interaction of the 1-pbase and the MWCNT sidewall and the six-membered carbon rings of the MWCNT.6 The MWCNT were observed to undergo a phase transfer from

  6. Thiazoles as corrosion inhibitors for mild steel in formic and acetic acid solutions

    Microsoft Academic Search

    M. A. Quraishi; H. K. Sharma

    2005-01-01

    2-(N,N-dimethylamino) benzylidene imino-4-(4-methyl phenyl)-1,3-thiazole (DIMPT), 2-benzylidene imino-4-(4-methyl phenyl)-1,3-thiazole (BIMPT), 2-salicylidene imino-4-(4-methyl phenyl)-1,3-thiazole (SIMPT) and 2-cinnamylidene imino-4-(4-methyl phenyl)-1,3-thiazole (CIMPT) were synthesized in the laboratory and their influence on the inhibition of corrosion of mild steel in 20 formic acid and 20 acetic acid was investigated by weight loss and potentiodynamic polarization techniques. The inhibition efficiency of these compounds was found to

  7. Proposing buffer zones and simple technical solutions for safeguarding river water quality and public health

    NASA Astrophysics Data System (ADS)

    Podimata, M. V.; Bekri, E. S.; Yannopoulos, P. C.

    2012-04-01

    Alfeios River Basin (ARB) constitutes one of the major hydrologic basins (?3650km2) of Peloponnisos peninsula in Southern Greece. It is drained by Alfeios River and its tributaries, such as Lousios, Ladhon, Erymanthos, Kladheos, Selinous etc. The present manuscript takes a closer look at the importance of tributary basins and focuses on Erymanthos sub-basin that covers about 360 km2. Erymanthos River springs from Erymanthos Mountain that reaches altitudes of 2200 m and discharges 10 m3/sec, approximately, during the winter period, presenting a sound decrease from half to about an order of magnitude during summertime. Two factors stand out as reasons to select Erymanthos sub-basin as a case study. First, the sub-basin presents a significant variety of ecosystems and comprises a very important river system, since Erymanthos Tributary satisfies, among other uses, drinking water supply for a great majority of citizens in the region. Second, authors' experience of the study area in Research Program Pythagoras II, funded by the European Social Fund (ESF) and the Operational Program for Educational and Vocational Training II (EPEAEK II) of Greece, offers a basis for better understanding of the real problems in the area. Erymanthos watershed, in fact, faces a lot of pressures, in several levels, provoked by human activities and Erymanthos Tributary is vulnerable to pollution. Recognizing the importance of clean water for healthy people, a developing economy, and a sustainable environment, the challenge of the present paper is elaborating human-induced pressures in the study area, analyzing their effects, estimating pollution factors and proposing integrated solutions/tools and a number of methodologies/initiatives used to overcome the problem of contaminating water supply in a catchment that lacks of wastewater treatment and disposal systems. The preservation of a good ecological status in Erymanthos River is not only a necessity for achieving the goals of EU Water Framework Directive (WFD) 2000/60, but a practical necessity for the safeguarding of public health and ecosystem health, in general. The present study aims at developing a simple methodology for assessing spatial distribution characteristics of pollution in Erymanthos catchment. Pollution loads at various sites in Erymanthos watershed were illustrated with Geographical Information System (GIS). Flow rates of Erymanthos River were also taken into consideration. Based on previous studies, in situ river discharges have been compared to simulated discharges in order to calibrate the rainfall-runoff model ENNS which can then predict future scenarios regarding the river flow rates with consideration of climate change effects. The goal of this study is to detect the pertinent points and suggest a) suitable buffer zones in areas with high pollution risk and b) simple technical works in order to prevent the main channel of Erymanthos River from direct polluting discharges. The above systems could also act supportively in groundwater enrichment, forest protection and soil erosion prevention. Authors believe that the results of the study could assist authorities and engineers to design and develop strategies of improving river water quality and safeguarding public health. The proposed measures may be applicable to other catchments as well.

  8. Stability of curcumin in buffer solutions and characterization of its degradation products

    Microsoft Academic Search

    Ying-Jan Wang; Min-Hsiung Pan; Ann-Lii Cheng; Liang-In Lin; Yuan-Soon Ho; Chang-Yao Hsieh; Jen-Kun Lin

    1997-01-01

    The degradation kinetics of curcumin under various pH conditions and the stability of curcumin in physiological matrices were investigated. When curcumin was incubated in 0.1 M phosphate buffer and serum-free medium, pH 7.2 at 37°C, about 90% decomposed within 30 min. A series of pH conditions ranging from 3 to 10 were tested and the result showed that decomposition was

  9. Size Control of (99m)Tc-tin Colloid Using PVP and Buffer Solution for Sentinel Lymph Node Detection.

    PubMed

    Kim, Eun-Mi; Lim, Seok Tae; Sohn, Myung-Hee; Jeong, Hwan-Jeong

    2015-06-01

    Colloidal particle size is an important characteristic that allows mapping sentinel nodes in lymphoscintigraphy. This investigation aimed to introduce different ways of making a (99m)Tc-tin colloid with a size of tens of nanometers. All agents, tin fluoride, sodium fluoride, poloxamer-188, and polyvinylpyrrolidone (PVP), were mixed and labeled with (99m)Tc. Either phosphate or sodium bicarbonate buffers were used to adjust the pH levels. When the buffers were added, the size of the colloids increased. However, as the PVP continued to increase, the size of the colloids was controlled to within tens of nanometers. In all samples, phosphate buffer added PVP (30 mg) stabilized tin colloid ((99m)Tc-PPTC-30) and sodium bicarbonate solution added PVP (50 mg) stabilized tin colloid ((99m)Tc-BPTC-50) were chosen for in vitro and in vivo studies. (99m)Tc-BPTC-50 (<20 nm) was primarily located in bone marrow and was then secreted through the kidneys, and (99m)Tc-PPTC-30 (>100 nm) mainly accumulated in the liver. When a rabbit was given a toe injection, the node uptake of (99m)Tc-PPTC-30 decreased over time, while (99m)Tc-BPTC-50 increased. Therefore, (99m)Tc-BPTC-50 could be a good candidate radiopharmaceutical for sentinel node detection. The significance of this study is that nano-sized tin colloid can be made very easily and quickly by PVP. PMID:26028937

  10. Nanofiltration of rhodium tris(triphenylphosphine) catalyst in ethyl acetate solution

    NASA Astrophysics Data System (ADS)

    Shaharun, Maizatul S.; Mustafa, Ahmad K.; Taha, Mohd F.

    2012-09-01

    Solvent resistant nanofiltration (SRNF) using polymer membranes has recently received enhanced attention due to the search for cleaner and more energy-efficient technologies. The large size of the rhodium tris(triphenylphosphine) [HRh(CO)(PPh3)3] catalyst (>400 Da) - relative to other components of the hydroformylation reaction provides the opportunity for a membrane separation based on retention of the catalyst species while permeating the solvent. The compatibility of the solvent-polyimide membrane (DuraMem{trade mark, serif} 200 and DuraMem{trade mark, serif} 500) combinations was assessed in terms of the membrane stability in solvent plus non-zero solvent flux at 2.0 MPa. Good HRh(CO)(PPh3)3 rejection (>0.95) and solvent fluxes of 9.9 L/m2?h1 at 2.0 MPa were obtained in the catalyst-ethyl acetate-DuraMem 500 system. The effect of pressure and catalyst concentration on the solvent flux and catalyst rejection was conducted on the catalyst-ethyl acetate-membrane systems. Increasing pressure substantially improved both solvent flux and catalyst rejection, while increasing catalyst concentration was found to be beneficial in terms of substantial increases in catalyst rejection without significantly affecting solvent flux.

  11. Effect of borate buffer on the photolysis of riboflavin in aqueous solution.

    PubMed

    Ahmad, Iqbal; Ahmed, Sofia; Sheraz, Muhammad Ali; Vaid, Faiyaz H M

    2008-11-13

    The photolysis of riboflavin (RF) in the presence of borate buffer (0.1-0.5M) at pH 8.0-10.5 has been studied using a specific multicomponent spectrophotometric method for the determination of RF and photoproducts, formylmethylflavin (FMF), lumichrome (LC) and lumiflavin (LF). The overall first-order rate constants for the photolysis of RF (1.55-4.36 x 10(-2)min(-1)) and the rate constants for the formation of FMF (1.16-3.52 x 10(-2)min(-1)) and LC (0.24-0.84 x 10(-2)min(-1)) have been determined. The values of all these rate constants decrease with an increase in buffer concentration suggesting the inhibition of photolysis reaction by borate species. The kinetic data support the formation of a RF-borate complex involving the ribityl side chain to cause the inhibition of photolysis. The second-order rate constants for the borate inhibited reaction range from 1.17-3.94 x 10(-2)M(-1)min(-1). The log k-pH profiles for the reaction at various buffer concentrations indicate a gradual increase in rate, with pH, up to 10 followed by a decrease in rate at pH 10.5 probably due to ionization of RF and quenching of fluorescence by borate species. A graph of second-order rate constants against pH is a sigmoid curve showing that the rate of photolysis increases with an increase in pH. The results suggest the involvement of excited singlet state, in addition to excited triplet state, in the formation of LC. PMID:18760621

  12. Habit changes of NaBrO 3 crystals grown from aqueous solution doped with sodium acetate

    NASA Astrophysics Data System (ADS)

    Sone, Masayo; Inoue, Tetsuo; Yanagiya, Shin-ichiro; Mori, Atsushi

    2002-04-01

    The effects of doping of sodium acetate upon the habit changes of NaBrO 3 crystals have been investigated. The crystals were grown from aqueous solution under the following conditions: (i) supersaturations, ln (C/C e)=0-0.4 , ( Ce: equilibrium mol fraction); (ii) growth temperatures, 15-43°C. The gross morphologies of crystals have taken on three distinct forms: tetrahedral {1 1 1} habit, cubic {1 0 0} and intermediate ({1 1 1}+{1 0 0}) habits. The result of habit changes was shown in a plot of growth temperature against supersaturation as compared to the results from non-doping and doping of 1.15 mol% acetic acid (J. Crystal Growth 158 (1996) 336; J. Crystal Growth 212 (2000) 507). The dependency of the growth rates upon the growth temperatures was investigated under the conditions where the supersaturation was kept constant. It was found that the growth rates of {1 0 0} were drastically reduced at higher growth temperatures.

  13. Calcium buffering is required to maintain bone stiffness in saline solution.

    PubMed

    Gustafson, M B; Martin, R B; Gibson, V; Storms, D H; Stover, S M; Gibeling, J; Griffin, L

    1996-09-01

    This work determined whether mineral dissolution due to prolonged testing or storage of bone specimens in normal saline would alter their elastic modulus. In one experiment, small pieces of equine third metacarpal bone were soaked in normal saline supplemented with varying amounts of CaCl2. Changing Ca ion concentrations in the bath were monitored and the equilibrium concentration was determined. In a second experiment, the elastic moduli of twenty 4 x 10 x 100 mm equine third metacarpal beams were determined non-destructively in four-point bending. Half the beams were then soaked for 10 days in normal saline, and the other half in saline buffered to the bone mineral equilibrium point with Ca ions. Modulus measurements were repeated at 6 and 10 days. The equilibrium Ca ion concentration for bone specimens was found to be 57.5 mg l-1. The modulus of bone specimens soaked in normal saline significantly diminished 2.4%, whereas the modulus of those soaked in calcium-buffered saline did not change significantly. PMID:8872276

  14. The preparation of accelerator targets by the evaporation of acetate-organic solutions in the presence of NH/sub 3/ gas

    SciTech Connect

    Cai, S.Y.; Ghiorso, A.; Hoffman, D.C.

    1987-03-01

    The chemical methods described in this paper have been developed for preparation of isotopic targets for bombardment by accelerator-produced ions. Three systems are compared: nitrate-, chloride-, and acetate-organic solutions. The best method was found to be the metallic acetate-organic solution system, evaporated onto the substrate in the presence of ammonia gas. A detailed procedure is given for this method. The targets obtained by the acetate-organic solution system are uniform and adherent. The hydroxide forms fine crystals of good quality for target thicknesses from a few ..mu..g/cm/sup 2/ to several mg/cm/sup 2/. Thicknesses up to 5 mg/cm/sup 2/ of Eu as the oxide were obtained by this method. The process is simple and fast. 18 refs., 1 tab.

  15. Comparative spectroscopic and mechanistic study of chelation properties of fisetin with iron in aqueous buffered solutions. Implications on in vitro antioxidant activity.

    PubMed

    Dimitri? Markovi?, Jasmina M; Markovi?, Zoran S; Brdari?, Tanja P; Filipovi?, Nenad D

    2011-05-01

    Fisetin (3,3',4',7-tetrahydroxyflavone) has been investigated for its ability to bind iron in a wide range of pH values of acetate and phosphate buffered solutions. To assess the relevant interactions of iron with fisetin, combined spectroscopic (UV/visible, Raman, MS) and theoretical approaches were used. The chelation sites, stoichiometry, stability and the dependence of the complexes structures on pH were defined. The results pointed to the formation of two iron-fisetin complexes with stoichiometries of 1 : 1 and 1 : 2, depending on the pH. Results of vibrational analysis and theoretical calculations implicated the 3-hydroxyl-4-carbonyl group as a chelating site in acidic media while catechol (3'-hydroxyl-4'-hydroxyl) group was identified as the chelating group in neutral and alkaline media. Determined relative, conditional, stability constants with iron-fisetin were in the range from 6 × 10(4) dm(3) mol(-1) to 7 × 10(9) dm(6) mol(-2). Competition experiments demonstrated that fisetin bound iron less strongly than EDTA and citric acid under the investigated experimental conditions. Rate constant values calculated for the fast step of the DPPH reduction for fisetin and the iron-fisetin complex are k(1) = 225.75 dm(3) mol(-1) s(-1) and k(1) = 658.00 dm(3) mol(-1) s(-1). These values fit within the interval of the rate constant values which are typical for antioxidants which have a single polyphenolic nucleus. The equilibrium geometries, optimized at the B3LYP/6-311 + G(d,p) and M06/6-311 + G(d,p) levels of theory, predicted structural modifications between the ligand molecule in the free state and in the complex structure. The theoretical model has been validated by both vibrational and electronic spectroscopies. PMID:21431152

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

    PubMed

    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

    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

  17. Basics of base in hemodialysis solution: Dialysate buffer production, delivery and decontamination.

    PubMed

    Desai, N

    2015-01-01

    Hemodialysis requires the use of high volumes of freshly prepared, clean dialysate to foster the removal of low molecular weight metabolites (i.e., urea) and to correct the electrolyte and acid-base imbalance of chronic renal failure. Dialysate is produced by mixing clean, AAMI grade water with both an acid and base concentrate. This purpose of this report is to describe production, mixing and delivery of the buffer component of dialysate, and to also to address the cost, safety and feasibility of producing online bicarbonate. As endotoxin contaminated dialysate has been associated with the release of key mediators in acute and chronic inflammatory diseases associated with long-term hemodialysis therapy, aspects of disinfecting a bicarbonate delivery loop are also addressed. PMID:26199467

  18. Inhibitory effect of hydroxypropyl methylcellulose acetate succinate on drug recrystallization from a supersaturated solution assessed using nuclear magnetic resonance measurements.

    PubMed

    Ueda, Keisuke; Higashi, Kenjirou; Yamamoto, Keiji; Moribe, Kunikazu

    2013-10-01

    We examined the inhibitory effect of hydroxypropyl methylcellulose acetate succinate (HPMC-AS) on drug recrystallization from a supersaturated solution using carbamazepine (CBZ) and phenytoin (PHT) as model drugs. HPMC-AS HF grade (HF) inhibited the recrystallization of CBZ more strongly than that by HPMC-AS LF grade (LF). 1D-1H NMR measurements showed that the molecular mobility of CBZ was clearly suppressed in the HF solution compared to that in the LF solution. Interaction between CBZ and HF in a supersaturated solution was directly detected using nuclear Overhauser effect spectroscopy (NOESY). The cross-peak intensity obtained using NOESY of HF protons with CBZ aromatic protons was greater than that with the amide proton, which indicated that CBZ had hydrophobic interactions with HF in a supersaturated solution. In contrast, no interaction was observed between CBZ and LF in the LF solution. Saturation transfer difference NMR measurement was used to determine the interaction sites between CBZ and HF. Strong interaction with CBZ was observed with the acetyl substituent of HPMC-AS although the interaction with the succinoyl substituent was quite small. The acetyl groups played an important role in the hydrophobic interaction between HF and CBZ. In addition, HF appeared to be more hydrophobic than LF because of the smaller ratio of the succinoyl substituent. This might be responsible for the strong hydrophobic interaction between HF and CBZ. The intermolecular interactions between CBZ and HPMC-AS shown by using NMR spectroscopy clearly explained the strength of inhibition of HPMC-AS on drug recrystallization. PMID:24025080

  19. Interfacial energetics of globular–blood protein adsorption to a hydrophobic interface from aqueous-buffer solution

    PubMed Central

    Krishnan, Anandi; Liu, Yi-Hsiu; Cha, Paul; Allara, David; Vogler, Erwin A

    2005-01-01

    Adsorption isotherms of nine globular proteins with molecular weight (MW) spanning 10–1000?kDa confirm that interfacial energetics of protein adsorption to a hydrophobic solid/aqueous-buffer (solid–liquid, SL) interface are not fundamentally different than adsorption to the water–air (liquid–vapour, LV) interface. Adsorption dynamics dampen to a steady-state (equilibrium) within a 1?h observation time and protein adsorption appears to be reversible, following expectations of Gibbs' adsorption isotherm. Adsorption isotherms constructed from concentration-dependent advancing contact angles ?a of buffered-protein solutions on methyl-terminated, self-assembled monolayer surfaces show that maximum advancing spreading pressure, ?amax, falls within a relatively narrow 10

  20. Inhibition mechanism of hydroxypropyl methylcellulose acetate succinate on drug crystallization in gastrointestinal fluid and drug permeability from a supersaturated solution.

    PubMed

    Ueda, Keisuke; Higashi, Kenjirou; Kataoka, Makoto; Yamashita, Shinji; Yamamoto, Keiji; Moribe, Kunikazu

    2014-10-01

    The effects of drug-crystallization inhibitor in bile acid/lipid micelles solution on drug permeation was evaluated during the drug crystallization process. Hydroxypropyl methylcellulose acetate succinate (HPMC-AS) was used as a drug-crystallization inhibitor, which efficiently suppressed dexamethasone (DEX) crystallization in a gastrointestinal fluid model containing sodium taurocholate (NaTC) and egg-phosphatidylcholine (egg-PC). Changes of molecular state of supersaturated DEX during the DEX crystallization process was monitored in real time using proton nuclear magnetic resonance (1H NMR). It revealed that DEX distribution to bulk water and micellar phases formed by NaTC and egg-PC was not changed during the DEX crystallization process even in the presence of HPMC-AS. DEX permeation during DEX crystallization was evaluated using dissolution/permeability system. The combination of crystallization inhibition by HPMC-AS and micellar encapsulation by NaTC and egg-PC led to considerably higher DEX concentrations and improvement of DEX permeation at the beginning of the DEX crystallization process. Crystallization inhibition by HPMC-AS can efficiently work even in the micellar solution, where NaTC/egg-PC micelles encapsulates some DEX. It was concluded that a crystallization inhibitor contributed to improvement of permeation of a poorly water-soluble drug in gastrointestinal fluid. PMID:24953904

  1. Evaluation of an enhanced oxidation method for the destruction of ethylene diamine tetra-acetic acid (EDTA) and related compounds in aqueous solution

    Microsoft Academic Search

    Narinder Bains; Martin Goosey; Runveer Hayer

    2003-01-01

    Ethylene diamine tetra-acetic acid (EDTA) and other chelates are widely employed in the electroless copper plating solutions and related chemistries used in printed circuit board (PCB) manufacturing. EDTA in particular, imparts many benefits to these processes but it is also becoming increasingly undesirable from an effluent treatment and environmental perspective. Consequently, there is a need to remove EDTA and similar

  2. Haemolysis of various mammalian erythrocytes in sodium chloride, glucose and phosphate-buffer solutions

    Microsoft Academic Search

    Toshiaki Matsuzawa; Yasushi Ikarashi

    1979-01-01

    Summary Mouse, rat, rabbit, hamster, cow, pig, sheep, guinea- pig, dog and human erythrocytes were studied. A 0·9% or stronger solution of sodium chloride com- pletely prevented haemolysis; sheep and pig erythro- cytes appeared the more fragile, while human and dog erythrocytes were not haemolized in concentrations of 0·4% or more. Haemolysis of human, rabbit, cow, hamster, guineapig, pig and

  3. Amidolytic, procoagulant, and activation-suppressing proteins produced by contact activation of blood factor XII in buffer solution.

    PubMed

    Golas, Avantika; Yeh, Chyi-Huey Joshua; Siedlecki, Christopher A; Vogler, Erwin A

    2011-12-01

    The relative proportions of enzymes with amidolytic or procoagulant activity produced by contact activation of the blood zymogen factor XII (FXII, Hageman factor) in buffer solution depends on activator surface chemistry/energy. As a consequence, chromogenic assay of amidolytic activity (cleavage of amino acid bonds in s-2302 chromogen) does not correlate with the traditional plasma coagulation time assay for procoagulant activity (protease activity inducing clotting of blood plasma). Amidolytic activity did not vary significantly with activator particle surface energy, herein measured as water adhesion tension ?(o)=?(lv)(o)cos?(a) ; where ?(lv)(o) is pure buffer interfacial tension and ?(a) is the advancing contact angle. By contrast, procoagulant activity varied as a parabolic-like function of ?(o), high at both hydrophobic and hydrophilic extremes of activator surface energy and falling through a broad minimum within a 20

  4. Acid neutralizing processes in an alpine watershed front range, Colorado, U.S.A.-1: Buffering capacity of dissolved organic carbon in soil solutions

    USGS Publications Warehouse

    Iggy, Litaor M.; Thurman, E.M.

    1988-01-01

    Soil interstitial waters in the Green Lakes Valley, Front Range, Colorado were studied to evaluate the capacity of the soil system to buffer acid deposition. In order to determine the contribution of humic substances to the buffering capacity of a given soil, dissolved organic carbon (DOC) and pH of the soil solutions were measured. The concentration of the organic anion, Ai-, derived from DOC at sample pH and the concentration of organic anion, Ax- at the equivalence point were calculated using carboxyl contents from isolated and purified humic material from soil solutions. Subtracting Ax- from Ai- yields the contribution of humic substances to the buffering capacity (Aequiv.-). Using this method, one can evaluate the relative contribution of inorganic and organic constituents to the acid neutralizing capacity (ANC) of the soil solutions. The relative contribution of organic acids to the overall ANC was found to be extremely important in the alpine wetland (52%) and the forest-tundra ecotone (40%), and somewhat less important in the alpine tundra sites (20%). A failure to recognize the importance of organic acids in soil solutions to the ANC will result in erroneous estimates of the buffering capacity in the alpine environment of the Front Range, Colorado. ?? 1988.

  5. Immobilizing DNA on gold via thiol modification for atomic force microscopy imaging in buffer solutions.

    PubMed

    Hegner, M; Wagner, P; Semenza, G

    1993-12-28

    Thiols, dialkylsulfides, and dialkyldisulfides are known to be chemisorbed with high affinity on gold. We have prepared DNAs of specific length and sequence carrying thiol groups at each end. For this purpose, primers with an HS-(CH2)6-arm at the 5'-end were used to amplify segments of plasmid DNA via the polymerase chain reaction. These thiolated DNAs bind strongly to the large, ultraflat Au surfaces which we have recently described [Hegner, M. et al. (1993) Surface Sci. 291, 39-46], and can be imaged by AFM in liquids (aqueous solutions or propanol). The lengths obtained in the AFM images are consistent with the DNA being in a native B-conformation. PMID:8282109

  6. Determination of electrochemical parameters and corrosion rate for carbon steel in un-buffered sodium chloride solutions using a superposition model

    Microsoft Academic Search

    Luis Cáceres; Tomás Vargas; Leandro Herrera

    2007-01-01

    Corrosion of carbon steel in un-buffered NaCl solutions was studied applying linear potential sweep technique to a rotating disk electrode. Current–potential curves were obtained from linear potential sweep at a rate of 1mVs?1 in solution with concentrations in the range 0.02–1M NaCl and rotation rates in the range 170–370rads?1, at 22°C. Potential sweeps, which were conducted in the potential range

  7. Influence of temperature, chloride ions and chromium element on the electronic property of passive film formed on carbon steel in bicarbonate\\/carbonate buffer solution

    Microsoft Academic Search

    D. G. Li; Y. R. Feng; Z. Q. Bai; J. W. Zhu; M. S. Zheng

    2007-01-01

    The influences of temperature, chloride ions and chromium element on the electronic property of passive film formed on carbon steel in NaHCO3\\/Na2CO3 buffer solution are investigated by capacitance measurement and electrochemical impedance spectroscopy (EIS). The results show that the passive film appears n-type semiconductive character; with increasing the solution temperature, the addition of chromium into carbon steel and increasing the

  8. Molecular Structure of Sodium acetate

    NSDL National Science Digital Library

    2002-08-26

    Sodium acetate is known for its ability to supercool. It freezes at 130 degrees, but can exist as a liquid at a much lower temperature. In order to melt solidified sodium acetate, however, every single crystal must liquify, otherwise the material will recrystallize. Sodium acetate has been used as a deicer for roads and runways. It is also used a component of buffer systems and in the manufacture of pharmaceuticals and heat pads. The compound is quite stable. It may act as an irritant and be harmful if inhaled or absorbed through the skin.

  9. Determination of copper, cadmium, lead and bismuth in phosphoric acid solutions by atomic-absorption spectrometry after extraction with diethylammonium diethyldithiocarbamate and butyl acetate.

    PubMed

    Nikolova, B; Jordanov, N

    1982-10-01

    The possibility of applying diethylammonium diethyldithiocarbamate and butyl acetate for the extraction of copper, cadmium, lead and bismuth from molar solutions of orthophosphoric acid, and from solutions containing up to 55% pyrophosphoric acid and 20% tripolyphosphoric acid has been investigated. Some characteristics of the various diethylammonium diethyldithiocarbamate-butyl acetate-phosphoric acid systems are described. Suitable conditions have been found for flame atomic-absorption spectrometric determination of the ions extracted. This extraction/AAS approach has been used to determine copper, cadmium, lead and bismuth in some iron-, aluminium- and tin-containing samples dissolved in concentrated orthophosphoric acid. The same approach is used for determining 10(-5)-10(-6)% copper, cadmium and lead in orthophosphoric acid and in alkali-metal mono and dihydrogen phosphates. PMID:18963249

  10. Passivity of 316L stainless steel in borate buffer solution studied by Mott–Schottky analysis, atomic absorption spectrometry and X-ray photoelectron spectroscopy

    Microsoft Academic Search

    Zhicao Feng; Xuequn Cheng; Chaofang Dong; Lin Xu; Xiaogang Li

    2010-01-01

    The passivity of 316L stainless steel in borate buffer solution has been investigated by Mott–Schottky, atomic absorption spectrometry (AAS) and X-ray photoelectron spectroscopy (XPS). The results indicate that the polarization curve in the passive region possesses several turning potentials (0 VSCE, 0.2 VSCE, 0.4 VSCE, 0.6 VSCE and 0.85 VSCE). The passive films formed at turning potentials perform different electrochemical

  11. Disinfection of bronchoscopes, contaminated in vitro with Mycobacterium tuberculosis, Mycobacterium avium-intracellulare and Mycobacterium chelonae in sputum, using stabilized, buffered peracetic acid solution (‘Nu-Cidex’)

    Microsoft Academic Search

    A. M. Middleton; M. V. Chadwick; H. Gaya

    1997-01-01

    The efficacy of 0·35% stabilized buffered peracetic acid solution (‘Nu-Cidex’) against clinical isolates of Mycobacterium tuberculosis, Mycobacterium avium-intracellulare and Mycobacterium chelonae in homogenized sputum was tested. An in-use method, using an automated bronchoscope washing machine, showed that over 10 cycles, at a disinfectant contact time of 5 min, M. tuberculosis and M. chelonae were effectively eradicated from the bronchoscope, even

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

    PubMed

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

    2011-05-01

    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

  13. The application of AC impedance to study the performance of lacquered aluminium specimens in acetic acid solution

    Microsoft Academic Search

    J. D Scantlebury; K Gali?

    1997-01-01

    Aluminium tubes with single and double coat solvent based and water based lacquers, based on epoxy-phenolic resins, were analysed. To determine the electrochemical parameters to correlate with the actual behaviour of a collapsible tube, impedance spectroscopy was used. The measurements were performed in 3% (v\\/v) acetic acid, at room temperature. After impedance measurements specimens surface were analysed by scanning electron

  14. Eslicarbazepine acetate.

    PubMed

    McCormack, Paul L; Robinson, Dean M

    2009-01-01

    Eslicarbazepine acetate, a prodrug of eslicarbazepine (S-licarbazepine), is a novel, voltage-gated sodium channel antagonist under development for the adjunctive treatment of adult patients experiencing treatment-refractory partial-onset seizures. * In phase III trials, eslicarbazepine acetate 800 and 1200 mg once daily significantly reduced seizure frequency compared with placebo over 12 weeks of maintenance treatment in adults experiencing partial-onset seizures who were taking 1-3 concomitant antiepileptic drugs. * During long-term, open-label treatment for up to 1 year, eslicarbazepine acetate at a median dosage of 800 mg once daily produced sustained reductions from baseline in seizure frequency. * Long-term treatment with eslicarbazepine acetate significantly improved from baseline health-related quality of life as assessed by the Quality-of-Life in Epilepsy Inventory-31 instrument. Similarly, eslicarbazepine acetate significantly reduced depressive symptoms assessed by the Montgomery-Asberg Depression Rating Scale. * Eslicarbazepine acetate was generally well tolerated in clinical trials. The majority of treatment-emergent adverse events were of mild to moderate severity and most occurred early in treatment. PMID:19062776

  15. Dissolution and compaction of albite sand in distilled water and pH-buffered carboxylic acid solutions: experiments at 100 degrees and 160 degrees C 

    E-print Network

    Carpenter, Thomas Doyle

    1995-01-01

    of difunctional anions such as oxalate and malonate (Carothers and Kharaka, 1978; Surdam et al. , 1984; Workman and Hanor, 1985; Fisher, 1987; MacGowan and Surdam, 1988; Fisher and Boles, 1990). Organic acid anions found in formation waters have an average...) determined the rates of dissolution for orthoclase m pH-buffered solutions containing oxalate at 70' and 95'C. Oxalate was shown to increase the dissolution rate by a factor of four compared to oxalate-free solutions at a similar pH. In these batch...

  16. Effects of alcohol and buffer treatments on the activity and enantioselectivity of Candida rugosa lipase.

    PubMed

    Takaç, Serpil; Unlü, Ay?e Ezgi

    2009-01-01

    Several treatments were employed on Candida rugosa lipase (CRL) to improve its biocatalytic performance. Besides conventional alcohol treatment conditions, the effects of pH of the buffer solution used in the treatment as well as the changes in stirring, dialysis, and centrifugation steps of the treatment procedure were investigated for the first time for the resolution of racemic naproxen methyl ester. The highest enantioselectivity and conversion in S-naproxen production were achieved by CRL treated with pH 7.5 buffer solution. The elimination of the centrifugation step resulted in an increase in the enantioselectivity, whereas alcohol treatment of CRL was found to be inconvenient for S-naproxen production. Higher activity for p-nitrophenyl acetate was achieved when 20% butanol and pH 4 buffer solution were used, and when dialysis and stirring times were shortened. PMID:19291575

  17. TES buffer-induced phase separation of aqueous solutions of several water-miscible organic solvents at 298.15 K: Phase diagrams and molecular dynamic simulations

    NASA Astrophysics Data System (ADS)

    Taha, Mohamed; Lee, Ming-Jer

    2013-06-01

    Water and the organic solvents tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1-propanol, 2-propanol, tert-butanol, acetonitrile, or acetone are completely miscible in all proportions at room temperature. Here, we present new buffering-out phase separation systems that the above mentioned organic aqueous solutions can be induced to form two liquid phases in the presence of a biological buffer 2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid (TES). The lower liquid phase is rich in water and buffer, and the upper phase is organic rich. This observation has both practical and mechanistic interests. The phase diagrams of these systems were constructed by experimental measurements at ambient conditions. Molecular dynamic (MD) simulations were performed for TES + water + THF system to understand the interactions between TES, water, and organic solvent at molecular level. Several composition-sets for this system, beyond and inside the liquid-liquid phase-splitting region, have been simulated. Interestingly, the MD simulation for compositions inside the phase separation region showed that THF molecules are forced out from the water network to start forming a new liquid phase. The hydrogen-bonds, hydrogen-bonds lifetimes, hydrogen-bond energies, radial distribution functions, coordination numbers, the electrostatic interactions, and the van der Waals interactions between the different pairs have been calculated. Additionally, MD simulations for TES + water + tert-butanol/acetonitrile/acetone phase separation systems were simulated. The results from MD simulations provide an explanation for the buffering-out phenomena observed in [TES + water + organic solvent] systems by a mechanism controlled by the competitive interactions of the buffer and the organic solvent with water. The molecular mechanism reported here is helpful for designing new benign separation materials.

  18. An efficient buffer-mediated control between free radical substitution and proton-coupled electron transfer: dehalogenation of iodoethane by the ?-hydroxyethyl radical in aqueous solution.

    PubMed

    Ljubi?, Ivan; Matasovi?, Brunislav; Bonifa?i?, Marija

    2013-11-01

    A remarkable buffer-mediated control between free-radical substitution (FRS) and proton-coupled electron transfer (PCET) is demonstrated for the reaction between iodoethane and the ?-hydroxyethyl radical in neutral aqueous solution in the presence of bicarbonate or phosphate buffer. The reaction is initiated by the ?-radiolysis of the water solvent, and the products, either the iodine atom (FRS) or anion (PCET), are analysed using ion chromatographic and spectrophotometric techniques. A detailed insight into the mechanism is gained by employing density functional theory (M06-2X), Møller-Plesset perturbation treatment to the second order (MP2), and multireference methods (CASSCF/CASPT2). Addition of a basic buffer anion is indispensable for the reaction to occur and the competition between the two channels depends subtly on its proton accepting affinity, with FRS being the dominant channel in the phosphate and PCET in the bicarbonate containing solutions. Unlike the former, the latter channel sustains a chain-like process which significantly enhances the dehalogenation. The present systems furnish an example of the novel PCET/FRS dichotomy, as well as insights into possibilities of its efficient control. PMID:24061544

  19. Solution-processed nanocomposites containing molybdenum oxide and gold nanoparticles as anode buffer layers in plasmonic-enhanced organic photovoltaic devices.

    PubMed

    Tan, Kim-Shih; Chuang, Ming-Kai; Chen, Fang-Chung; Hsu, Chain-Shu

    2013-12-11

    Solution-processed nanocomposites containing molybdenum oxide (MoO3) and gold nanoparticles (Au NPs) have been used as anode buffer layers in organic photovoltaic devices (OPVs). The resulting devices exhibit a remarkable enhancement in power conversion efficiency after Au NPs were incorporated into the device. Such enhancements can be attributed to the localized surface plasmon resonance induced by the metallic nanostructures. We have also found that the rate of exciton generation and the probability of exciton dissociation were increased. Furthermore, the devices made of the MoO3 buffer layer containing Au NPs exhibited superior stability. This work opens up the possibility of fabricating OPVs with both high efficiency and a prolonged lifetime. PMID:24229393

  20. The interaction of sodium dodecyl sulfate and urea with cat-fish collagen solutions in acetate buffer: hydrodynamic and thermodynamic studies

    Microsoft Academic Search

    Chellan Rose; Asit B. Mandal

    1996-01-01

    Cat-fish collagen was extracted and characterized. Shrinkage temperature of cat-fish collagen is 54.5°C. SDS-PAGE pattern indicated that the cat-fish collagen is Type I in nature. The ratio of proline and hydroxyproline is 1:2 and it suggests cat-fish collagen is vertebrate. The molecular weight of cat-fish collagen was determined by using molecular sieve chromatography and it was found to be 3

  1. Natural dissolved organic matter mobilizes Cd but does not affect the Cd uptake by the green algae Pseudokirchneriella subcapitata (Korschikov) in resin buffered solutions.

    PubMed

    Verheyen, Liesbeth; Versieren, Liske; Smolders, Erik

    2014-09-01

    Natural dissolved organic matter (DOM) can have contrasting effects on metal bioaccumulation in algae because of complexation reactions that reduce free metal ion concentrations and because of DOM adsorption to algal surfaces which promote metal adsorption. This study was set up to reveal the role of different natural DOM samples on cadmium (Cd) uptake by the green algae Pseudokirchneriella subcapitata (Korschikov). Six different DOM samples were collected from natural freshwater systems and isolated by reverse osmosis. In addition, one (13)C enriched DOM sample was isolated from soil to trace DOM adsorption to algae. Algae were exposed to standardized solutions with or without these DOM samples, each exposed at equal DOM concentrations and at equal non-toxic Cd(2+) activity (?4 nM) that was buffered with a resin. The DOM increased total dissolved Cd by factors 3-16 due to complexation reactions at equal Cd(2+) activity. In contrast, the Cd uptake was unaffected by DOM or increased maximally 1.6 fold ((13)C enriched DOM). The (13)C analysis revealed that maximally 6% of algal C was derived from DOM and that this can explain the small increase in biomass Cd. It is concluded that free Cd(2+) and not DOM-complexed Cd is the main bioavailable form of Cd when solution Cd(2+) is well buffered. PMID:24874007

  2. Molecular Structure of Phenylmercuric acetate

    NSDL National Science Digital Library

    2004-11-10

    Phenylmercuric acetate is white to white-yellow crystalline powder that is odorless. This phenyl mercury compound is used mainly as a fungicide, herbicide, slimicide and bacteriocide. Phenylmercuric acid serves as a preservative in canned paint, eye ointments and drops, injectable solutions, skin disinfectants and in cosmetics products such as hair shampoos, mouthwashes and toothpastes. It is also used in contraceptive gels and foams. Phenylmercuric acetate is prepared by interaction of benzene with mercuric acetate in glacial acetic acid. Phenylmercuric acetate's former production and use as a fungicide and as a mildew inhibitor in paints may have resulted in its direct release to the environment. This substance is very toxic to aquatic organisms and may be hazardous to the environment.

  3. Growth of thick La2Zr2O7 buffer layers for coated conductors by polymer-assisted chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Zhao, Yong; Xia, Yudong; Guo, Chunsheng; Cheng, C. H.; Zhang, Yong; Zhang, Han

    2015-06-01

    La2Zr2O7 (LZO) epitaxial films have been deposited on LaAlO3 (LAO) (1 0 0) single-crystal surface and bi-axially textured NiW (2 0 0) alloy substrate by polymer-assisted chemical solution deposition, and afterwards studied with XRD, SEM and AFM approaches. Highly in-plane and out-of-plane oriented, dense, smooth, crack free and with a sufficient thickness (>240 nm) LZO buffer layers have been obtained on LAO (1 0 0) single-crystal surface; The films deposited on NiW (2 0 0) alloy substrate are also found with high degree in-plane and out-of-plane texturing, good density with pin-hole-free, micro-crack-free nature and a thickness of 300 nm. Highly epitaxial 500 nm thick YBa2Cu3O7-x (YBCO) thin film exhibits the self-field critical current density (Jc) reached 1.3 MA/cm2 at 77 K .These results demonstrate the LZO epi-films obtained with current techniques have potential to be a buffer layer for REBCO coated conductors.

  4. Biomimetic apatite formation on calcium phosphate-coated titanium in Dulbecco's phosphate-buffered saline solution containing CaCl(2) with and without fibronectin.

    PubMed

    Chen, Cen; Lee, In-Seop; Zhang, Sheng-Min; Yang, Hyeong Cheol

    2010-06-01

    Calcium phosphate (CaP) thin films with different degrees of crystallinity were coated on the surfaces of commercially pure titanium by electron beam evaporation. The details of apatite nucleation and growth on the coating layer were investigated in Dulbecco's phosphate-buffered saline solutions containing calcium chloride (DPBS) or DPBS with fibronectin (DPBSF). The surfaces of the samples were examined by field emission scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The concentrations of fibronectin and calcium ions (Ca(2+)) were monitored by the bicinchoninic acid method (BCA) and use of a calcium assay kit (DICA-500), respectively. Apatite initially formed at the fastest rate on the CaP-coated samples with the lowest degree of crystallinity and reached the maximum Ca(2+) concentration after immersion in DPBS solution for 15min. After 15min the concentration of Ca(2+) decreased with the growth of apatite on the coating layers. For all the samples the maximum Ca(2+) concentration in the DPBS solutions decreased with increasing crystallinity and immersion time to reach the maximum concentration increased. The presence of fibronectin in the DPBS solutions delayed the formation and affected the morphology of the apatite. Fibronectin incorporated into apatite deposited on the surface of titanium did not affect its biological activity in terms of promoting osteoblast adhesion. PMID:19962459

  5. The buffering-out effect and phase separation in aqueous solutions of EPPS buffer with 1-propanol, 2-propanol, or 2-methyl-2-propanol at T = 298.15 K

    Microsoft Academic Search

    Mohamed Taha; Han-Lan Teng; Ming-Jer Lee

    Buffering-out is a new liquid–liquid phase separation phenomenon observed in mixtures containing a buffer as a mass separating agent. The (liquid+liquid) equilibrium (LLE) and (solid+liquid+liquid) equilibrium (SLLE) data were measured for the ternary systems {3-[4-(2-hydroxyethyl)piperazin-1-yl]propanesulfonic acid (EPPS) buffer+1-propanol, 2-propanol, or 2-methyl-2-propanol+water} at T=298.15K under atmospheric pressure. The phase boundary data were fitted to an empirical equation relating to the concentrations

  6. Effect of different concentrations of acetic, citric, and propionic acid dipping solutions on bacterial contamination of raw chicken skin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial contamination of raw, processed poultry may include spoilage bacteria and foodborne pathogens. We evaluated different combinations of organic acid (OA) wash solutions for their ability to reduce bacterial contamination of raw chicken skin and to inhibit growth of spoilage bacteria and path...

  7. Cathode buffer layers based on vacuum and solution deposited poly(3,4-ethylenedioxythiophene) for efficient inverted organic solar cells

    E-print Network

    Barr, Miles C.

    Vacuum and solution processed versions of poly(3,4-ethylenedioxythiophene) (PEDOT) are used as cathode interlayers in inverted organic photovoltaic cells comprising tetraphenyldibenzoperiflanthene as the electron donor and ...

  8. Effect of Cadmium and Iron on Rice (Oryza Sativa L.) Plant in Chelator-Buffered Nutrient Solution

    Microsoft Academic Search

    Tapan Adhikari; Elisha Tel-Or; Yael Libal; Moshe Shenker

    2006-01-01

    To better understand the mechanisms responsible for differences in uptake and distribution of cadmium (Cd), nutrient-solution experiments were conducted with different varieties of rice (Oryza sativa), ‘Khitish’ and ‘CNRH3’. The plants were grown in a complete nutrient solution with different levels of pCd (-log free Cd activity) and pFe [-log free iron (Fe) activity]. The required concentrations of chelating agent

  9. Measuring system for the rapid determination of the concentration of coated micrometer-sized paramagnetic particles suspended in aqueous buffer solutions

    NASA Astrophysics Data System (ADS)

    Hawkins, Peter; Luxton, Richard; Macfarlane, James

    2001-01-01

    Coated paramagnetic particles (PMPs) with diameters typically 1-10 ?m are widely used in biomedical investigations, including immunoassays and molecular biology. In this article we describe an investigation into a measuring system to determine rapidly the concentration of PMPs in suspension in a buffer solution in a pot. The measuring system is based on a coil in a parallel resonant circuit with a capacitor. The sample pot is placed in the coil, causing the inductance of the coil to increase and the resonant frequency to decrease. The decrease in resonant frequency is directly related to the concentration of PMPs in the pot. Using a circuit based on a Colpitts oscillator it is possible to determine the concentration of PMPs in the pot with an error of about 10% over the range 0-9 mg g-1. Much more accurate measurements (error <1%) are possible using a circuit design based on a phase-locked loop.

  10. Thermal decomposition of the ammonium zinc acetate citrate precursor for aqueous chemical solution deposition of ZnO

    Microsoft Academic Search

    K. Van Werde; D. Mondelaers; G. Vanhoyland; D. Nelis; M. K. Van Bael; J. Mullens; L. C. Van Poucke; B. Van Der Veken; H. O. Desseyn

    2002-01-01

    The thermal decomposition of an aqueous chemical solution deposition Zn2+-precursor is studied by HT-DRIFT (high temperature diffuse reflectance infrared Fourier transform spectroscopy), on-line coupled TGA-EGA (thermogravimetric analysis - evolved gas analysis by Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS)), and HT-XRD (high temperature X-ray diffraction). Using these complementary techniques, it is found that the a-hydroxyl group of the

  11. Solution Processing of Cadmium Sulfide Buffer Layer and Aluminum-Doped Zinc Oxide Window Layer for Thin Films Solar Cells

    NASA Astrophysics Data System (ADS)

    Alam, Mahboob; Islam, Mohammad; Achour, Amine; Hayat, Ansar; Ahsan, Bilal; Rasheed, Haroon; Salam, Shahzad; Mujahid, Mohammad

    2014-07-01

    Cadmium sulfide (CdS) and aluminum-doped zinc oxide (Al:ZnO) thin films are used as buffer layer and front window layer, respectively, in thin film solar cells. CdS and Al:ZnO thin films were produced using chemical bath deposition (CBD) and sol-gel technique, respectively. For CBD CdS, the effect of bath composition and temperature, dipping time and annealing temperature on film properties was investigated. The CdS films are found to be polycrystalline with metastable cubic crystal structure, dense, crack-free surface morphology and the crystallite size of either few nanometers or 12-17 nm depending on bath composition. In case of CdS films produced with 1:2 ratio of Cd and S precursors, spectrophotometer studies indicate quantum confinement effect, owing to extremely small crystallite size, with an increase in Eg value from 2.42 eV (for bulk CdS) to 3.76 eV along with a shift in the absorption edge toward 330 nm wavelength. The optimum annealing temperature is 400°C beyond which film properties deteriorate through S evaporation and CdO formation. On the other hand, Al:ZnO films prepared via spin coating of precursor sols containing 0.90-1.10 at.% Al show that, with an increase in Al concentration, the average grain size increases from 28 nm to 131 nm with an associated decrease in root-mean-square roughness. The minimum value of electrical resistivity, measured for the films prepared using 0.95 at.% Al in the precursor sol, is 2.7 × 10-4 ? ? cm. The electrical resistivity value rises upon further increase in Al doping level due to introduction of lattice defects and Al segregation to the grain boundary area, thus limiting electron transport through it.

  12. Chemical bath deposited (CBD)ZnO buffer layer for CIGS solar cells

    Microsoft Academic Search

    R. Mikami; H. Miyazaki; T. Abe; A. Yamada; M. Konagai

    2003-01-01

    Zinc oxide was grown by a chemical bath deposition (CBD) method and it was applied to a buffer layer for Cu(InGa)Se\\/sub 2\\/ solar cells. The film was deposited with a solution of zinc acetate (Zn(CH\\/sub 3\\/COO)) and ethylenediamine (NH\\/sub 2\\/CH\\/sub 2\\/CH\\/sub 2\\/NH\\/sub 2\\/) or ammonia (NH\\/sub 4\\/OH). The films grown with a NH\\/sub 4\\/OH-base solution showed good morphology and adhesion

  13. Labradorite dissolution in aqueous organic acid solutions: an experimental study 

    E-print Network

    Ahmed, MD. Raquib Uddin

    1995-01-01

    H-buffered solutions of 0.07m acetate(pHi=3.5, 4.7, 5.4), 0.07m acetate0.005m oxalate (pHi=4.4), and 0.07m acetate-0.005m citrate (pHi=4.4). Pore fluid flow was essentially constant (25-30 ml/hr) for rate studies and semi-static and slow (0.03-0.3 ml/hr) for solubility...

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

    PubMed

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

    1996-02-01

    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

  15. Phytophthora erythroseptica (Pink Rot) Development in Russet Norkotah Potato Grown in Buffered Hydroponic Solutions I. Calcium Nutrition Effects

    Microsoft Academic Search

    Jared H. Benson; Brad Geary; Jeffrey S. Miller; Von D. Jolley; Bryan G. Hopkins; Mikel R. Stevens

    2009-01-01

    Phytophthora erythroseptica Pethyb. causes a disease known as pink rot in potatoes, which is responsible for substantial pre and post harvest tuber loss.\\u000a Disease outbreaks are associated with excessive soil moisture, moderate temperature, late season development, and a lack of\\u000a potato cultivar resistance. Because disease resistance is becoming less effective, understanding other potential solutions\\u000a is critical. Mineral nutrition of plants

  16. Direct Measurement of 59Fe-Labeled Fe2+ Influx in Roots of Pea Using a Chelator Buffer System to Control Free Fe2+ in Solution.

    PubMed Central

    Fox, T. C.; Shaff, J. E.; Grusak, M. A.; Norvell, W. A.; Chen, Y.; Chaney, R. L.; Kochian, L. V.

    1996-01-01

    Fe2+ transport in plants has been difficult to quantify because of the inability to control Fe2+ activity in aerated solutions and non-specific binding of Fe to cell walls. In this study, a Fe(II)-3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4[prime]4"-disulfonic acid buffer system was used to control free Fe2+ in uptake solutions. Additionally, desorption methodologies were developed to adequately remove nonspecifically bound Fe from the root apoplasm. This enabled us to quantify unidirectional Fe2+ influx via radiotracer (59Fe) uptake in roots of pea (Pisum sativum cv Sparkle) and its single gene mutant brz, an Fe hyperaccumulator. Fe influx into roots was dramatically inhibited by low temperature, indicating that the measured Fe accumulation in these roots was due to true influx across the plasma membrane rather than nonspecific binding to the root apoplasm. Both Fe2+ influx and Fe translocation to the shoots were stimulated by Fe deficiency in Sparkle. Additionally, brz, a mutant that constitutively exhibits high ferric reductase activity, exhibited higher Fe2+ influx rates than +Fe-grown Sparkle. These results suggest that either Fe deficiency triggers the induction of the Fe2+ transporter or that the enhanced ferric reductase activity somehow stimulates the activity of the existing Fe2+ transport protein. PMID:12226276

  17. Catalytic ozonation of refractory organic model compounds in aqueous solution by aluminum oxide

    Microsoft Academic Search

    Mathias Ernst; Franck Lurot; Jean-Christophe Schrotter

    2004-01-01

    Batch experiments on catalytic ozonation in buffered and non-buffered solution of refractory organic compounds like oxalic, acetic, salicylic and succinic acids are presented. The concentration of dissolved organic carbon (DOC) in each test was 60mg\\/l and the applied batch procedure allowed a clear distinction between adsorptive and reaction processes. Results have confirmed that Al2O3 can be an effective catalyst for

  18. Acetate induced enhancement of photocatalytic hydrogen peroxide production from oxalic acid and dioxygen.

    PubMed

    Yamada, Yusuke; Nomura, Akifumi; Miyahigashi, Takamitsu; Ohkubo, Kei; Fukuzumi, Shunichi

    2013-05-01

    The addition of acetate ion to an O2-saturated mixed solution of acetonitrile and water containing oxalic acid as a reductant and 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh(+)-NA) as a photocatalyst dramatically enhanced the turnover number of hydrogen peroxide (H2O2) production. In this photocatalytic H2O2 production, a base is required to facilitate deprotonation of oxalic acid forming oxalate dianion, which acts as an actual electron donor, whereas a Brønsted acid is also necessary to protonate O2(•-) for production of H2O2 by disproportionation. The addition of acetate ion to a reaction solution facilitates both the deprotonation of oxalic acid and the protonation of O2(•-) owing to a pH buffer effect. The quantum yield of the photocatalytic H2O2 production under photoirradiation (? = 334 nm) of an O2-saturated acetonitrile-water mixed solution containing acetate ion, oxalic acid and QuPh(+)-NA was determined to be as high as 0.34, which is more than double the quantum yield obtained by using oxalate salt as an electron donor without acetate ion (0.14). In addition, the turnover number of QuPh(+)-NA reached more than 340. The reaction mechanism and the effect of solvent composition on the photocatalytic H2O2 production were scrutinized by using nanosecond laser flash photolysis. PMID:23631436

  19. Development of an Amperometric Acetic Acid Sensor in Organic System

    Microsoft Academic Search

    Shin Lin; Tse-Chuan Chou

    An amperometric method was developed by using a lead working electrode in acetonitrile organic solution for detecting acetic acid. The mechanisms of electrochemical reaction were corresponding to the reduction of acetic ions in acetonitrile organic solution. The steady state amperometric current resulted from the reduction of acetic ions to produce the aldehyde in a two-electron process. In the organic sensing

  20. REMOTE Shared Memory Buffer #2

    E-print Network

    ;#12;#12;Command Buffer Buffer Status Command Buffer Buffer Status Buffer StatusCommand Buffer Process RCS Process RCS Process RCS Write status messages Read command messages Module 1 Module 3 W rite com m and m

  1. Copper corrosion in buffered and non-buffered synthetic seawater: a comparative study

    Microsoft Academic Search

    JoãoPedro Ferreira; JoãoAlexandre Rodrigues; InêsTeodoraElias da Fonseca

    2004-01-01

    The electrochemical behaviour of copper in neutral buffered and non-buffered synthetic seawater and in pure chloride solutions has been studied by cyclic voltammetry, weight loss measurements, open circuit potential and scanning electron microscopy (SEM). Values of the repassivation potentials of Cu in non-buffered and buffered synthetic seawater, at 50 mV s -1, were 0.12 and 0.46 V vs. SCE, respectively. The sharpness, heights

  2. Evidences of the formation of a tin(IV) complex in citric-citrate buffer solution: A study based on voltammetric, FTIR and ab initio calculations

    NASA Astrophysics Data System (ADS)

    Bichara, Laura Cecilia; Fiori Bimbi, María Victoria; Gervasi, Claudio Alfredo; Alvarez, Patricia Eugenia; Brandán, Silvia Antonia

    2012-01-01

    We studied the Sn(IV)-complex, [Sn(C 6H 4O 7) 2] 2- formed after anodic dissolution of a tin surface through its passive oxide film in citric-citrate aqueous solution buffer pH 3. Tin-complex was experimentally characterized using infrared spectroscopy while ab initio calculations were made to study its structure and vibrational properties. These calculations gave us a precise knowledge of the normal modes of vibration taking into account that in the complex the molecule comprises a system of two citrate ions that are attached to a central Sn(IV) atom. The coordination about Sn(IV) consists of a distorted octahedral SnO 6 where two tridentate citrates are bonding to the central metal. The calculated harmonic vibrational frequencies are consistent with the experimental vibrational spectra. The theoretical calculations of the wavenumbers allowed us to obtain a tentative assignment of the observed spectral features. The nature of the different Sn-O and Sn ? O bonds in the complex and their topological properties were investigated by means of natural bond orbital (NBO) analysis and Bader's atoms in the molecule (AIM) theory, respectively.

  3. An experimental study of zinc chloride speciation from 300 to 600 °C and 0.5 to 2.0 kbar in buffered hydrothermal solutions

    USGS Publications Warehouse

    Cygan, G.L.; Hemley, J.J.; d'Angelo, W. M.

    1994-01-01

    The solubility of sphalerite (ZnS) was measured in KCl-HCl-H2O solutions at 300-600??C and 0.5-2.0 kbar. The silicate assemblage K-feldspar-muscovite (or andalusite)-quartz was used to buffer the solution to acid conditions, resulting in the total solubility reaction 2K+ + KAl2AlSi3O10(OH)2 + 6SiO2 + ZnS + nCl- = ZnCln(2-n) + 3KAlSi3O8 + H2S. (muscovite) (quartz) (sphalerite) (K-feldspar) A computer retrieval technique was used to derive average chloride ligand numbers for chlorozinc species at 0.25-2.0 molal total chloride. This technique mathematically solves for the average ligand number using a series of pertinent chemical relations at P and T. Mono- and di-chlorozinc species were found to predominate throughout the pressure-temperature-composition range investigated. The logarithms of the first and second dissociation constants for ZnCl20 were evaluated over the P-T range; for example, at 1 kbar, the values -0.41 and -1.42 were computed for the logarithm of the first dissociation constant, while -7.62 and -10.57 were computed for the logarithm of the second dissociation constant, for 400 and 500??C, respectively. Results are compared to past studies conducted at subcritical conditions and differ in that we find no evidence for more highly coordinated chloro-zinc species except possibly for ZnCl3- at 600??C, 1 and 2 kbar. Our results are consistent with electrostatic theory, which favors lower charged to neutral molecules in low dielectric-constant media. ?? 1994.

  4. Some Observations on the Emulsion Polymerization of Ethyl Methacrylate Initiated by Potassium Persulfate at 50°C in a Phosphate Buffer Solution of pH 6.85 and at a Low Monomer\\/Water Ratio

    Microsoft Academic Search

    T. K. Paul; M. Banerjee; R. S. Konar

    1981-01-01

    The emulsion polymerization of ethyl methacrylate initiated by the potassium persulfate (I) at 50°C in the presence of an anionic detergent (S), i.e., sodium lauryl sulfate at a low monomer\\/water ratio, has been ineestigated kinetically by the coneentional dilatometric and graeimetric methods in a phosphate buffer solution of pH 6.85. The number of latex particles per mL of the aqueous

  5. Method for regeneration of electroless nickel plating solution

    DOEpatents

    Eisenmann, Erhard T. (5423 Vista Sandia, NE., Albuquerque, NM 87111)

    1997-01-01

    An electroless nickel(EN)/hypophosphite plating bath is provided employing acetic acid/acetate as a buffer and which is, as a result, capable of perpetual regeneration while avoiding the production of hazardous waste. A regeneration process is provided to process the spent EN plating bath solution. A concentrated starter and replenishment solution is provided for ease of operation of the plating bath. The regeneration process employs a chelating ion exchange system to remove nickel cations from spent EN plating solution. Phosphites are then removed from the solution by precipitation. The nickel cations are removed from the ion exchange system by elution with hypophosphorous acid and the nickel concentration of the eluate adjusted by addition of nickel salt. The treated solution and adjusted eluate are combined, stabilizer added, and the volume of resulting solution reduced by evaporation to form the bath starter and replenishing solution.

  6. Method for regeneration of electroless nickel plating solution

    DOEpatents

    Eisenmann, E.T.

    1997-03-11

    An electroless nickel(EN)/hypophosphite plating bath is provided employing acetic acid/acetate as a buffer and which is, as a result, capable of perpetual regeneration while avoiding the production of hazardous waste. A regeneration process is provided to process the spent EN plating bath solution. A concentrated starter and replenishment solution is provided for ease of operation of the plating bath. The regeneration process employs a chelating ion exchange system to remove nickel cations from spent EN plating solution. Phosphites are then removed from the solution by precipitation. The nickel cations are removed from the ion exchange system by elution with hypophosphorus acid and the nickel concentration of the eluate adjusted by addition of nickel salt. The treated solution and adjusted eluate are combined, stabilizer added, and the volume of resulting solution reduced by evaporation to form the bath starter and replenishing solution. 1 fig.

  7. Ferroelectric thin film bismuth titanate prepared from acetate precursor

    Microsoft Academic Search

    Yanxia Lu; David T. Hoelzer; Walter A. Schulze; Bmce Tuttle; B. G. Potter

    1994-01-01

    Bismuth titanate (Bi4Ti3O12) thin films were fabricated by spin coat deposition-rapid thermal processing (RTP) technique. Acetate derived solution for deposition was synthesized by blending dissolved bismuth acetate in aqueous acetic acid, and then adding with titanium acetate. A series of electrically insulating, semiconducting and conducting substrates were evaluated for Bi4 Ti3O12 films deposition. While X-ray diffraction and TEM analyses indicated

  8. An improvement to the ligand optimisation method (LOM) for measuring the apparent dissociation constant and ligand purity in Ca2+ and Mg2+ buffer solutions.

    PubMed

    McGuigan, John A S; Kay, James W; Elder, Hugh Y

    2014-01-01

    In Ca(2+)/Mg(2+) buffers the calculated ionised concentrations ([X(2+)]) can vary by up to a factor of seven. Since there are no defined standards it is impossible to check calculated [X(2+)], making measurement essential. The ligand optimisation method (LOM) is an accurate method to measure [X(2+)] in Ca(2+)/Mg(2+) buffers; independent estimation of ligand purity extends the method to pK(/) < 4. To simplify calculation, Excel programs ALE and AEC were compiled for LOM and its extension. This paper demonstrates that the slope of the electrode in the pX range 2.000-3.301 deviates from Nernstian behaviour as it depends on the value of the lumped interference, ?. ALE was modified to include this effect; this modified program SALE, and the programs ALE and AEC were used on simulated data for Ca(2+)-EGTA and Mg(2+)-ATP buffers, to calculate electrode and buffer characteristics as a function of ?. Ca(2+)-electrodes have a ? < 10(-6) mol/l and there was no difference amongst the three methods. The ? for Mg(2+)-electrodes lies between 10(-5) and 1.5 (?) 10(-5) mol/l and calculated [Mg(2+)] with ALE were around 3% less than the true value. SALE and AEC correctly predicted [Mg(2+)]. SALE was used to recalculate K(/) and pK(/) on measured data for Ca(2+)-EGTA and Mg(2+)-EDTA buffers. These results demonstrated that it is pK(/) that is normally distributed. Until defined standards are available, [X(2+)] in Ca(2+)/Mg(2+) buffers have to be measured. The most appropriate method is to use Ca(2+)/Mg(2) electrodes combined with the Excel programs SALE or AEC. PMID:24836054

  9. Pallidol hexa­acetate ethyl acetate monosolvate

    PubMed Central

    Mao, Qinyong; Taylor, Dennis K.; Ng, Seik Weng; Tiekink, Edward R. T.

    2013-01-01

    The entire mol­ecule of pallidol hexa­acetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis­[4-(acet­yloxy)phen­yl]-4b,5,9b,10-tetra­hydro­indeno­[2,1-a]indene-1,3,6,8-tetrayl tetra­acetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate mol­ecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009 ?). Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexa­acetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100?Å) is 54.73?(6)°, indicating a significant fold in the mol­ecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70?(5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carb­oxy)—C—C torsion angles = ?70.24?(14), ?114.43?(10) and ?72.54?(13)°]. In the crystal, a three-dimensional architecture is sustained by C—H?O inter­actions which encompass channels in which the disordered ethyl acetate mol­ecules reside. PMID:24046702

  10. Adaptively biased sequential importance sampling for rare events in reaction networks with comparison to exact solutions from finite buffer dCME method

    NASA Astrophysics Data System (ADS)

    Cao, Youfang; Liang, Jie

    2013-07-01

    Critical events that occur rarely in biological processes are of great importance, but are challenging to study using Monte Carlo simulation. By introducing biases to reaction selection and reaction rates, weighted stochastic simulation algorithms based on importance sampling allow rare events to be sampled more effectively. However, existing methods do not address the important issue of barrier crossing, which often arises from multistable networks and systems with complex probability landscape. In addition, the proliferation of parameters and the associated computing cost pose significant problems. Here we introduce a general theoretical framework for obtaining optimized biases in sampling individual reactions for estimating probabilities of rare events. We further describe a practical algorithm called adaptively biased sequential importance sampling (ABSIS) method for efficient probability estimation. By adopting a look-ahead strategy and by enumerating short paths from the current state, we estimate the reaction-specific and state-specific forward and backward moving probabilities of the system, which are then used to bias reaction selections. The ABSIS algorithm can automatically detect barrier-crossing regions, and can adjust bias adaptively at different steps of the sampling process, with bias determined by the outcome of exhaustively generated short paths. In addition, there are only two bias parameters to be determined, regardless of the number of the reactions and the complexity of the network. We have applied the ABSIS method to four biochemical networks: the birth-death process, the reversible isomerization, the bistable Schlögl model, and the enzymatic futile cycle model. For comparison, we have also applied the finite buffer discrete chemical master equation (dCME) method recently developed to obtain exact numerical solutions of the underlying discrete chemical master equations of these problems. This allows us to assess sampling results objectively by comparing simulation results with true answers. Overall, ABSIS can accurately and efficiently estimate rare event probabilities for all examples, often with smaller variance than other importance sampling algorithms. The ABSIS method is general and can be applied to study rare events of other stochastic networks with complex probability landscape.

  11. Properties of Pb(0.92)La(0.08)Zr(0.52)Ti(0.48)O(3) thin films grown on SrRuO(3) buffered nickel and silicon substrates by chemical solution deposition

    SciTech Connect

    Narayanan, M.; Ma, B.; Tong, S.; Koritala, R.; Balachandran, U. (Energy Systems); ( MSD)

    2012-01-01

    Ferroelectric film-on-foil capacitors are suitable to replace discrete passive components in the quest to develop electronic devices that show superior performance and are smaller in size. The film-on-foil approach is the most practical method to fabricate such components. Films of Pb{sub 0.92}La{sub 0.08}Zr{sub 0.52}Ti{sub 0.48}O{sub 3} (PLZT) were deposited on SrRuO{sub 3} (SRO) buffer films over nickel and silicon substrates. High-quality polycrystalline SRO thin-film electrodes were first deposited by chemical solution deposition. A phase pure, dense, uniform microstructure with grain size <100 nm was obtained in films crystallized at 700 C. The room-temperature resistivity of the SRO films crystallized at 700 C was {approx}800-900 {mu}{Omega}-cm. The dielectric properties of sol-gel derived PLZT capacitors on SRO-buffered nickel were evaluated as a function of temperature, bias field, and frequency, and the results were compared to those of the same films on silicon substrates. The comparison demonstrated the integrity of the buffer layer and its compatibility with nickel substrates. Device-quality dielectric properties were measured on PLZT films deposited on SRO-buffered nickel foils and found to be superior to those for PLZT on SRO-buffered silicon and expensive platinized silicon. These results suggest that SRO films can act as an effective barrier layer on nickel substrates suitable for embedded capacitor applications.

  12. Spray pyrolysis deposition of ZnO thin films on FTO coated substrates from zinc acetate and zinc chloride precursor solution at different growth temperatures

    Microsoft Academic Search

    Ü. Alver; A. Kudret; S. Tekerek

    2011-01-01

    ZnO thin films were fabricated using zinc chloride and zinc acetate precursors by the spray pyrolysis technique on FTO coated glass substrates. The ZnO films were grown in different deposition temperature ranges varying from 400 to 550°C. Influences of substrate temperature and zinc precursors on crystal structure, morphology and optical property of the ZnO thin films were investigated. XRD patterns

  13. Poly(ethylene-co-vinyl acetate) (EVA) as wax inhibitor of a Brazilian crude oil: oil viscosity, pour point and phase behavior of organic solutions

    Microsoft Academic Search

    André L. C Machado; Elizabete F Lucas; Gaspar González

    2001-01-01

    Several techniques have been used to minimize the problems caused by the wax deposition, and the continuous addition of polymeric inhibitors is considered an attractive technological alternative. The addition of copolymers like polyacrylates, polymethacrylates or poly(ethylene-co-vinyl acetate) (EVA) permit to inhibit the deposition phenomenon; nonetheless, this effect is specific, i.e. similar copolymers present different performance depending on their physical–chemical properties

  14. Dissolution reaction and surface iron speciation of UICC crocidolite in buffered solution at pH 7.4: A combined ICP-OES, XPS and TEM investigation

    NASA Astrophysics Data System (ADS)

    Pacella, Alessandro; Fantauzzi, Marzia; Turci, Francesco; Cremisini, Carlo; Montereali, Maria Rita; Nardi, Elisa; Atzei, Davide; Rossi, Antonella; Andreozzi, Giovanni B.

    2014-02-01

    The dissolution reaction and the surface modifications of crocidolite asbestos fibres incubated for 0.5, 1, 24, 48, 168 and 1440 h in a phosphate buffered solution at pH 7.4 with and without hydrogen peroxide were investigated. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) was used to monitor the ion release into solution, X-ray Photoelectron Spectroscopy (XPS) was performed to unveil the chemistry of the leached surface, and High Resolution Transmission Electron Microscopy (HR-TEM) was carried out to monitor the structural modifications of the fibres. No significant differences were observed between dissolution experiments carried out with and without H2O2 with the exception of results after the first hour, from which it may be inferred that the dissolution proceeds faster in the presence of H2O2 but only in its very early steps. Congruent mobilization of Si and Mg from crocidolite was observed, increasing with time especially in the range between 1 and 48 h, while Ca decreased after 48 h and Fe was not detected at any incubation time. In the undersaturated conditions (0-48 h), dissolution rate of UICC crocidolite fibres has been estimated to be d(Si)/dt = 0.079 ?mol h-1. The fibre surface modification is continuous with time: XPS results showed a regular depletion of Si and Mg and enrichment of Fe along dissolution. The Fe2p3/2 signal on the surface was fitted with four components at 709.0, 710.5, 711.6 and 712.8 eV binding energy values corresponding to: (i) Fe(II)-O and (ii) Fe(III)-O surrounded by oxygen atoms in the silicate structure, (iii) Fe(III)-OOH as a product of the dissolution process, and (iv) Fe in a phosphate precipitate (Fe-P), respectively. The evolution of Fe speciation on the crocidolite surface was followed by integrating the four photoemission peaks, and results showed that the oxidative environment promotes the formation of Fe(III)-O (up to 37% Fetot) and of Fe-P species (up to 16% Fetot), which are found on the fibre surface at the end of the dissolution experiment. HR-TEM showed that the crocidolite lattice structure, the fibrous habit and the high aspect ratio are preserved upon leaching, while Fe-bearing nanoparticles, likely amorphous and possibly displaced on top of the fibres, become clearly visible. As a conclusion, coating of the crocidolite fibres was demonstrated to occur due to precipitation of Fe-rich phases (both phosphates and oxide-hydroxides). The occurrence of such iron armouring may modulate asbestos toxicity and possibly be the initial step in the formation of asbestos ferruginous bodies.

  15. Buffer strips trap contaminants

    E-print Network

    Nebraska-Lincoln, University of

    ideal width for riparian buffer strips in Midwest. They trap sediment, nutrients and pesticides. That maater Buffer strips trap contaminants Three research and demonstration projects seek to determine kes riparian buffer strips a valuable tool in preventing nonpo int sour ce pollution, according

  16. VIRTUAL FRAME BUFFER INTERFACE

    NASA Technical Reports Server (NTRS)

    Wolfe, T. L.

    1994-01-01

    Large image processing systems use multiple frame buffers with differing architectures and vendor supplied user interfaces. This variety of architectures and interfaces creates software development, maintenance, and portability problems for application programs. The Virtual Frame Buffer Interface program makes all frame buffers appear as a generic frame buffer with a specified set of characteristics, allowing programmers to write code which will run unmodified on all supported hardware. The Virtual Frame Buffer Interface converts generic commands to actual device commands. The virtual frame buffer consists of a definition of capabilities and FORTRAN subroutines that are called by application programs. The virtual frame buffer routines may be treated as subroutines, logical functions, or integer functions by the application program. Routines are included that allocate and manage hardware resources such as frame buffers, monitors, video switches, trackballs, tablets and joysticks; access image memory planes; and perform alphanumeric font or text generation. The subroutines for the various "real" frame buffers are in separate VAX/VMS shared libraries allowing modification, correction or enhancement of the virtual interface without affecting application programs. The Virtual Frame Buffer Interface program was developed in FORTRAN 77 for a DEC VAX 11/780 or a DEC VAX 11/750 under VMS 4.X. It supports ADAGE IK3000, DEANZA IP8500, Low Resolution RAMTEK 9460, and High Resolution RAMTEK 9460 Frame Buffers. It has a central memory requirement of approximately 150K. This program was developed in 1985.

  17. Technical Note The b-function and variable stream buffer mapping: a note on ‘A GIS method for riparian water quality buffer generation’

    Microsoft Academic Search

    Wei-Ning Xiang; Wendy Lee Stratton

    1996-01-01

    Mapping variable stream buffers in a vector environment in which buffer width values are delineated often yields inaccurate results. Possible vector solutions are either ineffective or inefficient, An alternate raster approach is presented here in which a buffer effectiveness-achievement function (b-function) is introduced to map desirable buffer zones at an individual cell level based upon areal differentiations in physical and

  18. An all chemical solution deposition approach for the growth of highly textured CeO2 cap layers on La2Zr2O7-buffered long lengths of biaxially textured Ni W substrates for YBCO-coated conductors

    Microsoft Academic Search

    S. Engel; K. Knoth; R. Hühne; L. Schultz; B. Holzapfel

    2005-01-01

    A reel-to-reel, dip coating process has been developed to continuously deposit epitaxial La2Zr2O7 (LZO) and CeO2 on 5 m long cube-textured {100} (001)Ni tapes. Recent results for La2Zr2O7 and CeO2 buffer layers deposited on long lengths of Ni substrate for the realization of YBa2Cu3O7-x (YBCO)-coated conductors are presented. The major achievement is the development of a new all chemical solution

  19. Preparation of vinyl acetate

    DOEpatents

    Tustin, Gerald Charles (Kingsport, TN); Zoeller, Joseph Robert (Kingsport, TN); Depew, Leslie Sharon (Kingsport, TN)

    1998-01-01

    This invention pertains to the preparation of vinyl acetate by contacting a mixture of hydrogen and ketene with a heterogeneous catalyst containing a transition metal to produce acetaldehyde, which is then reacted with ketene in the presence of an acid catalyst to produce vinyl acetate.

  20. Doped with Sodium Acetate and Metallic Sodium

    NASA Astrophysics Data System (ADS)

    Tada, Satoki; Isoda, Yukihiro; Udono, Haruhiko; Fujiu, Hirofumi; Kumagai, Shunji; Shinohara, Yoshikazu

    2014-06-01

    We have investigated the thermoelectric properties of p-type Na-doped Mg2 Si0.25Sn0.75 solid solutions prepared by liquid-solid reaction and hot-pressing methods. Na was introduced into Mg2Si0.25Sn0.75 by using either sodium acetate (CH3COONa) or metallic sodium (2 N). The samples doped with sodium acetate consisted of phases with antifluorite structure and a small amount of MgO as revealed by x-ray diffraction, whereas the sample doped with metallic sodium contained the Sn, MgO, and Mg2SiSn phases. The hole concentrations of Mg1.975Na0.025Si0.25Sn0.75 doped by sodium acetate and metallic sodium were 1.84 × 1025 m-3 and 1.22 × 1025 m-3, respectively, resulting in resistivities of 4.96 × 10-5 ? m (sodium acetate) and 1.09 × 10-5 ? m (metallic sodium). The Seebeck coefficients were 198 ?V K-1 (sodium acetate) and 241 ?V K-1 (metallic sodium). The figures of merit for Mg1.975Na0.025Si0.25Sn0.75 were 0.40 × 10-3 K-1 (sodium acetate) and 0.25 × 10-3 K-1 (metallic sodium) at 400 K. Thus, sodium acetate is a suitable Na dopant for Mg2Si1- x Sn x .

  1. Miscibility studies on blends of cellulose acetate and nylon 6

    Microsoft Academic Search

    G. M Shashidhara; K. H Guruprasad; A Varadarajulu

    2002-01-01

    Miscibility studies on cellulose secondary acetate(CA)\\/Nylon 6(N6) blends have been carried out in this work. Dilute solution viscometry for the blend solutions using formic acid as the common solvent shows the existence of miscibility window.

  2. Buffer Therapy for Cancer

    PubMed Central

    Ribeiro, Maria de Lourdes C; Silva, Ariosto S.; Bailey, Kate M.; Kumar, Nagi B.; Sellers, Thomas A.; Gatenby, Robert A.; Ibrahim-Hashim, Arig; Gillies, Robert J.

    2013-01-01

    Oral administration of pH buffers can reduce the development of spontaneous and experimental metastases in mice, and has been proposed in clinical trials. Effectiveness of buffer therapy is likely to be affected by diet, which could contribute or interfere with the therapeutic alkalinizing effect. Little data on food pH buffering capacity was available. This study evaluated the pH and buffering capacity of different foods to guide prospective trials and test the effect of the same buffer (lysine) at two different ionization states. Food groups were derived from the Harvard Food Frequency Questionnaire. Foods were blended and pH titrated with acid from initial pH values until 4.0 to determine “buffering score”, in mmol H+/pH unit. A “buffering score” was derived as the mEq H+ consumed per serving size to lower from initial to a pH 4.0, the postprandial pH of the distal duodenum. To differentiate buffering effect from any metabolic byproduct effects, we compared the effects of oral lysine buffers prepared at either pH 10.0 or 8.4, which contain 2 and 1 free base amines, respectively. The effect of these on experimental metastases formation in mice following tail vein injection of PC-3M prostate cancer cells were monitored with in vivo bioluminescence. Carbohydrates and dairy products’ buffering score varied between 0.5 and 19. Fruits and vegetables showed a low to zero buffering score. The score of meats varied between 6 and 22. Wine and juices had negative scores. Among supplements, sodium bicarbonate and Tums® had the highest buffering capacities, with scores of 11 and 20 per serving size, respectively. The “de-buffered” lysine had a less pronounced effect of prevention of metastases compared to lysine at pH 10. This study has demonstrated the anti-cancer effects of buffer therapy and suggests foods that can contribute to or compete with this approach to manage cancer. PMID:24371544

  3. StackGuard: Automatic Adaptive Detection and Prevention of Buffer-Overflow Attacks

    Microsoft Academic Search

    Crispin Cowan; Calton Pu; Dave Maier; Heather Hinton; Jonathan Walpole; Peat Bakke; Steve Beattie; Aaron Grier; Perry Wagle; Qian Zhang

    1998-01-01

    This paper presents a systematic solution to the per- sistent problem of buffer overflow attacks. Buffer over- flow attacks gained notoriety in 1988 as part of the Morris Worm incident on the Internet. While it is fairly simple to fix individual buffer overflow vulnerabilities, buffer overflow attacks continue to this day. Hundreds of at- tacks have been discovered, and while

  4. Patterned buffer layer promotes maskless lateral epitaxial overgrowth of low-dislocation-density ZnO films in aqueous solution at low temperature

    NASA Astrophysics Data System (ADS)

    Chen, Hou-Guang; Shih, Yung-Hui; Yu, Ming-Yang

    2015-04-01

    In this article, we describe a facile approach, with the assistance of a stripe-patterned ZnAl2O4 buffer layer, for the maskless lateral epitaxial growth (LEO) of low-dislocation-density ZnO films. During hydrothermal processing, the selective-area epitaxial growth of ZnO mesas occurred preferentially on ZnAl2O4 stripes. The ZnO growth subsequently occurred in the lateral direction; eventually, adjacent stripe-patterned ZnO mesas coalesced to form a continuous film. The dislocation density at the coalesced LEO ZnO was 108 cm?2. The photoluminescence of LEO-grown ZnO films featured a strong near-band-edge ultraviolet emission, but other defect-related visible emissions were suppressed almost entirely, indicating a significant improvement in crystalline quality.

  5. The effect of acetic acid and acetate on CO2 corrosion of carbon steel

    Microsoft Academic Search

    Dong Liu; ZhenYu Chen; XingPeng Guo

    2008-01-01

    Purpose – The purpose of this paper is to consider the effect of acetic acid and acetate on the anodic and cathodic reactions of carbon steel present in CO2 corrosion. Design\\/methodology\\/approach – The corrosion behaviour of carbon steel (N80) in CO2-saturated 1% NaCl solution at 50°C and 0.1 MPa was investigated by using weight-loss tests, electrochemical methods (polarization curves and

  6. Tetragonal Chicken Egg White Lysozyme Solubility in Sodium Chloride Solutions

    NASA Technical Reports Server (NTRS)

    Forsythe, Elizabeth L.; Judge, Russell A.; Pusey, Marc L.

    1998-01-01

    The solubility of chicken egg white lysozyme, crystallized in the tetragonal form was measured in sodium chloride solutions from 1.6 to 30.7 C, using a miniature column solubility apparatus. Sodium chloride solution concentrations ranged from 1 to 7% (w/v). The solutions were buffered with 0.1 M sodium acetate buffer with the solubility being measured at pH values in 0.2 pH unit increments in the range pH 4.0 to 5.4, with data also included at pH 4.5. Lysozyme solubility was found to increase with increases in temperature and decreasing salt concentration. Solution pH has a varied and unpredictable effect on solubility.

  7. Norethisterone and norethisterone acetate.

    PubMed

    1979-12-01

    This monograph on norethisterone and its acetate (NOR) includes chemical and physical data (synonyms and trade names), structural and molecular formulae and molecular weight of NOR, chemical and physical properties of NOR, and the production, use, occurrence, and analysis of NOR. Production of NOR and its acetate, both of which are not known to occur naturally, occurs via conversion of estrone to its methyl ester which is reduced to estradiol 3-methyl ether with lithium aluminum hydride; NOR acetate is synthesized by acetylating NOR with acetic anhydride in pyridine. NOR has been used for human medicine in a variety of ways: 1) to treat amenorrhea, 2) to treat dysfunctional uterine bleeding, and 3) for treating endometriosis. It has also been used to treat premenstrual tension and dysmenorrhea. Medicinal use of NOR acetate is similar to that for NOR. Analytical procedures for determining NOR as a bulk chemical are presented tabularly. Biological data relevant to the evaluation of carcinogenic risk to humans are presented briefly. With experimental animals, when administered alone NOR and/or its acetate increased the incidence of benign liver tumors in male mice and of pituitary tumors in females; females also suffered granulosa-cell ovarian tumors. NOR in combination with an estrogen increased incidence of pituitary tumors in mice of both sexes. NOR is embryolethal in some species and produces virilization in female fetuses. It is concluded that there is limited evidence for the carcinogenicity of NOR and its acetate in animals. Human studies are not available, but NOR is implicated causally as a progestogenic element in side effects of combined oral contraceptive usage. PMID:120838

  8. Tri-State Buffer

    NSDL National Science Digital Library

    Bartelt, Terry L. M.

    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.

  9. A study of the synergistic interaction of asbestos fibers with cigarette tar extracts for the generation of hydroxyl radicals in aqueous buffer solution.

    PubMed

    Valavanidis, A; Balomenou, H; Macropoulou, I; Zarodimos, I

    1996-01-01

    Several models attempt to explain the synergistic increase in lung cancer among workers exposed to asbestos fibers, who were smokers at the same time. It is known that reactive oxygen species (ROS) are important mediators in asbestos-induced diseases, especially cancer. We studied quantitatively the formation of ROS (by spin trapping with DMPO) in aqueous buffer suspensions containing crocidolite (UICC), chrysotile (UICC and commercial, long fibers) alone, and in combination with aqueous cigarette tar extracts. It was observed that asbestos and cigarette tar act in a cooperative or synergistic way in the generation of hydroxyl radical spin adducts. Grinding of asbestos fibers and addition of EDTA (iron chelator) enhanced the intensity of the ESR signal. This enhancement progressed with time, probably due to the reaction of the extracted iron with the slow released hydrogen peroxide from tar extracts. It was observed a fivefold increase in the ESR signal (for crocidolite and aqueous tar extracts) in the formation of hydroxyl radicals via an iron-catalyzed Fenton reaction. These experimental results are suggest to be strong evidence to the fact that lung cancer has been found in asbestos workers exposed to high concentrations of fibers in the working environment who were smokers, and only rarely in nonsmokers. PMID:8728034

  10. Effects of acetic acid\\/acetic anhydride ratios on the properties of corn starch acetates

    Microsoft Academic Search

    Cherif Ibrahima Khalil Diop; Hai Long Li; Bi Jun Xie; John Shi

    2011-01-01

    Corn starch was pre-treated with acetic acid and then acetylated by acetic anhydride under microwave irradiation. The effects of molar ratios of these two reagents on the acetylation of starch were investigated. Starch acetate with a high degree of substitution (DS, 2.93) was obtained at a molar ratio (acetic acid\\/acetic anhydride) of 1:1. However, the DS should tend to decrease

  11. pH-dependent effect of magnesium sulfate on the stability of penicillin G potassium solution.

    PubMed

    Das Gupta, V; Stewart, K R

    1985-03-01

    The effect of magnesium sulfate on the stability of penicillin G potassium solutions (0.5 mg/mL) was investigated using a stability-indicating high-performance liquid chromatography method. The penicillin G potassium powder buffered with and without citrate was used. Twelve aqueous duplicate penicillin solutions with various concentrations of magnesium sulfate and with or without buffers were prepared and stored at room temperature. Data on clarity, pH values, and HPLC assay results were determined at intervals during the 10-day storage period. The results indicated that the presence of high concentrations of magnesium sulfate in unbuffered penicillin solutions can cause large pH changes and the degradation of penicillin. However, the effect of magnesium sulfate on the stability of penicillin G potassium was negligible in the buffered solutions. Solutions with a constant pH value of 5.6 prepared using 0.1 M acetate buffer with and without magnesium sulfate showed similar apparent first-order degradation after the 10-day storage period at 24 degrees C. During decomposition, the pH values of the unbuffered solutions decreased for three days and then started increasing in most solutions. The degradation of penicillin G potassium by magnesium sulfate in aqueous solutions resulted from decreases in pH values of the solutions. PMID:3985024

  12. Sodium bicarbonate and Alkaten as buffers in beef cattle diets 

    E-print Network

    Boerner, Benedict Joseph

    1985-01-01

    to decrease levels below control values while 3. 0% NaHCO 3 increased acetate. Propionate and butyr ate were similar across treaments. In contrast, decreased total VFA concentration was measured by Emmanuel et al. ( 1970). Although no individual acid...:50 ( cracked corn concentrate: roughage ) with no buffer, 2 ) 90: 10 with no buffer, 3) 50:50 with 1% 5, 4) 90: 10 with 1% 5, 5) 50:50 with 1% A and 6) 90: 10 with 1% A. In the feeding trial, 48 Hereford X Angus steers were fed diets 2, 4 and 6. Propionate...

  13. Evaluation of AmpouledTonometeredBufferSolutions as a Quality ControlSystemfor pH, p2, andPo2Measurement

    Microsoft Academic Search

    A. H. J. Maas; A. H. Veefklnd; R. A. M. Van den Camp; A. J. Teunissen; E. K. A. Winckers; A. P. Jansen

    In response to the need for an adequate quality-control system for blood-pH and blood-gas analyzers, we inves- tigated the practical application of ampouled phosphate- bicarbonate-thioride solutions tonometered with mixtwes of carbon dioxide, oxygen, and nitrogen.This system offers three discrete sets of pH, p02, Po2 values, which are consistent with normal and pathophysiologicaily high and low values. The stated values were

  14. Efficient Organic Photovoltaic Cells Using Hole-Transporting MoO3 Buffer Layers Converted from Solution-Processed MoS2 Films

    Microsoft Academic Search

    Shogo Kato; Ryo Ishikawa; Yosuke Kubo; Hajime Shirai; Keiji Ueno

    2011-01-01

    We introduce a new method to fabricate a MoO3 hole-transporting layer for organic photovoltaic cells (OPVs). We fabricated a MoS2 film from its solution and converted it to MoO3. MoS2 has a lamellar crystal structure similar to graphite, and it can be exfoliated into monolayer MoS2 dispersible in water. Li atoms were first intercalated into van der Waals gaps of

  15. Buffer Capacity of a Polyprotic Acid: First Derivative of the Buffer Capacity and pKa Values of Single and Overlapping Equilibria

    Microsoft Academic Search

    Agustin G. Asuero

    2007-01-01

    Buffer capacity appears in a variety of fields, and its approximate calculation is of practical importance for the design of new buffer solutions, being also a quantity related to titrations. The aims of this paper are (i) to devise simple expressions for the buffer capacity and its first derivative for a polyprotic acid, which may be easily extended to a

  16. Ulipristal acetate: in uterine fibroids.

    PubMed

    Croxtall, Jamie D

    2012-05-28

    Ulipristal acetate, a selective progesterone-receptor modulator, inhibits the proliferation and induces apoptosis of leiomyoma cells in vitro. It also modulates the expression of vascular endothelial growth factors and hormone receptors and modulates extracellular matrix breakdown in leiomyoma cells but not in myometrial cells. In two randomized, double-blind, multinational phase III trials of 13 weeks' duration in women aged 18-50 years with uterine fibroids, a once-daily regimen of oral ulipristal acetate 5 mg/day controlled excessive uterine bleeding (primary endpoint) in ?90% of patients. Ulipristal acetate 5 mg/day was more effective than placebo and was shown to be noninferior to intramuscular leuprolide acetate 3.75 mg once monthly in controlling uterine bleeding. Uterine bleeding was rapidly controlled by ulipristal acetate. Approximately half of recipients of ulipristal acetate 5 mg/day became amenorrhoeic within the first 10 days of treatment. Furthermore, uterine bleeding was controlled significantly more rapidly for recipients of ulipristal acetate than recipients of leuprolide acetate. A significantly greater median reduction from baseline in total fibroid volume was observed for recipients of ulipristal acetate 5 mg once daily than recipients of placebo following 13 weeks' treatment (coprimary endpoint). For patients who did not undergo surgery, the volume reduction was maintained for at least 6 months after discontinuing treatment. Ulipristal acetate was generally well tolerated in women with uterine fibroids. The incidence of hot flush occurred with a significantly lower frequency for recipients of ulipristal acetate than for recipients of leuprolide acetate. PMID:22568731

  17. The boundary lubrication of chemically grafted and cross-linked hyaluronic acid in phosphate buffered saline and lipid solutions measured by the surface forces apparatus.

    PubMed

    Yu, Jing; Banquy, Xavier; Greene, George W; Lowrey, Daniel D; Israelachvili, Jacob N

    2012-01-31

    High molecular weight hyaluronic acid (HA) is present in articular joints and synovial fluid at high concentrations; yet despite numerous studies, the role of HA in joint lubrication is still not clear. Free HA in solution does not appear to be a good lubricant, being negatively charged and therefore repelled from most biological, including cartilage, surfaces. Recent enzymatic experiments suggested that mechanically or physically (rather than chemically) trapped HA could function as an "adaptive" or "emergency" boundary lubricant to eliminate wear damage in shearing cartilage surfaces. In this work, HA was chemically grafted to a layer of self-assembled amino-propyl-triethoxy-silane (APTES) on mica and then cross-linked. The boundary lubrication behavior of APTES and of chemically grafted and cross-linked HA in both electrolyte and lipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) solutions was tested with a surface forces apparatus (SFA). Despite the high coefficient of friction (COF) of ? ? 0.50, the chemically grafted HA gel significantly improved the lubrication behavior of HA, particularly the wear resistance, in comparison to free HA. Adding more DOPC lipid to the solution did not improve the lubrication of the chemically grafted and cross-linked HA layer. Damage of the underlying mica surface became visible at higher loads (pressure >2 MPa) after prolonged sliding times. It has generally been assumed that damage caused by or during sliding, also known as "abrasive friction", which is the main biomedical/clinical/morphological manifestation of arthritis, is due to a high friction force and, therefore, a large COF, and that to prevent surface damage or wear (abrasion) one should therefore aim to reduce the COF, which has been the traditional focus of basic research in biolubrication, particularly in cartilage and joint lubrication. Here we combine our results with previous ones on grafted and cross-linked HA on lipid bilayers, and lubricin-mediated lubrication, and conclude that for cartilage surfaces, a high COF can be associated with good wear protection, while a low COF can have poor wear resistance. Both of these properties depend on how the lubricating molecules are attached to and organized at the surfaces, as well as the structure and mechanical, viscoelastic, elastic, and physical properties of the surfaces, but the two phenomena are not directly or simply related. We also conclude that to provide both the low COF and good wear protection of joints under physiological conditions, some or all of the four major components of joints-HA, lubricin, lipids, and the cartilage fibrils-must act synergistically in ways (physisorbed, chemisorbed, grafted and/or cross-linked) that are still to be determined. PMID:22148857

  18. Effect of surface chemistries and characteristics of Ti6Al4V on the Ca and P adsorption and ion dissolution in Hank's ethylene diamine tetra-acetic acid solution.

    PubMed

    Chang, E; Lee, T M

    2002-07-01

    This study examined the influence of chemistries and surface characteristics of Ti6Al4V on the adsorption of Ca and P species and ion dissolution behavior of the material exposed in Hank's solution with 8.0 mM ethylene diamine tetra-acetic acid at 37 degrees C. The variation of chemistries of the alloy and nano-surface characteristics (chemistries of nano-surface oxides, amphoteric OH group adsorbed on oxides, and oxide thickness) was effected by surface modification and three passivation methods (34% nitric acid passivation. 400 degrees C heated in air, and aged in 100 degrees C water). X-ray photoelectron spectroscopy and Auger electron spectroscopy were used for surface analyses. The chemistries of nano-surface oxides in a range studied should not change the capability of Ca and P adsorption. Nor is the capability affected significantly by amphoteric OH group and oxide thickness. However, passivations influence the surface oxide thickness and the early stage ion dissolution rate of the alloy. The rate-limiting step of the rate can be best explained by metal-ion transport through the oxide film, rather than hydrolysis of the film. Variation of the chemistries of titanium alloy alters the electromotive force potential of the metal, thereby affecting the corrosion and ion dissolution rate. PMID:12069333

  19. Differential Buffer Ring Oscillator

    E-print Network

    Ayazi, Farrokh

    Differential Buffer delay Ring Oscillator Replica-feedback current souce bias circuit VDD = 2.4 - 3. The clock generator is based on a 3-stage differential ring oscillator. The compensation technique to appropriately change the control voltage of the differential ring oscillator. Measurements made across

  20. A new method to clean industrial water from acetic acid via esterification

    Microsoft Academic Search

    C. L. Bianchi; V. Ragaini; C. Pirola; G. Carvoli

    2003-01-01

    The valorisation of very low concentration of acetic acid (6%, w\\/w) was investigated by reacting with n-butanol and 2-ethyl-1-hexanol taking advantage of the different solubilities of acetic acid and acetic ester in water. The esterification of very diluted solution of acetic acid with alcohol is a reversible reaction and the conversion is greatly restricted by equilibrium limitation. Therefore, the peculiarity

  1. Grain-oriented ferroelectric bismuth titanate thin film prepared from acetate precursor

    Microsoft Academic Search

    Yanxia Lu; David T. Hoelzer; Walter A. Schulze; Bruce Tuttle; B. G. Potter

    1996-01-01

    Bismuth titanate (Bi4Ti3O12) thin films were fabricated by a spin coating deposition and rapid thermal processing (RTP) technique. The acetate-derived solution for deposition was synthesized by blending dissolved bismuth acetate in aqueous acetic acid and then adding titanium acetate. A series of electrically insulating, semiconducting and conducting substrates were evaluated for Bi4Ti3O12 films deposition. X-ray diffraction indicated that the initial

  2. Effect of passivation on the dissolution behavior of Ti6A14V and vacuum-brazed Ti6A14V in Hank's ethylene diamine tetra-acetic acid solution Part I Ion release.

    PubMed

    Lee, T M; Chang, E; Yang, C Y

    1999-09-01

    This work aims to investigate the effects of three factors, namely: (1) two differently prepared materials (as-polished Ti6A14V and 2 h brazed Ti6A14V); (2) three different surface passivation treatments (34% nitric acid passivation, 400 degrees C heated in air, and aged in 100 degrees C de-ionized water); and (3) periods of immersion time (up to 32 days), on trace element release in Hank's ethylene diamine tetra-acetic acid (EDTA) solution. After passivation and autoclaving treatment, the specimens were immersed in 8.0 mM EDTA in Hank's solution and maintained at 37 degrees C for periods of time up to 32 days. The 400 degrees C -treated specimens exhibit a substantial reduction in constituent release, which may be attributed to the higher thickness and rutile structure of the surface oxides. For acid-passivated and water-aged treatments, a highly significant decrease in the trace levels of Ti, A1, and V is detected from the brazed Ti6A14V compared to those obtained from the Ti6A14V specimens. It is hypothesized that an anatase-rutile transformation of surface TiO_2 is likely to occur, accelerated by the elements of copper and nickel in the brazed specimens. In addition, a significant time-related decrease in constituent release rate is observed for all kinds of specimens throughout the 0-8 day experimental period. The implication of the results is discussed. PMID:15348105

  3. Evaluation of hypromellose acetate succinate (HPMCAS) as a carrier in solid dispersions.

    PubMed

    Tanno, Fumié; Nishiyama, Yuichi; Kokubo, Hiroyasu; Obara, Sakaé

    2004-01-01

    The utility of hypromellose acetate succinate (HPMCAS), a cellulosic enteric coating agent, as a carrier in a solid dispersion of nifedipine (NP) was evaluated in comparison with other polymers, including hypromellose (HPMC), hypromellose phthalate (HPMCP), methacrylic acid ethyl acrylate copolymer (MAEA), and povidone (PVP). An X-ray diffraction study showed that the minimum amount of HPMCAS required to make the drug completely amorphous was the same as that of other cellulosic polymers, and less than that in dispersions using non-cellulosic polymers. Hypromellose acetate succinate showed the highest drug dissolution level from its solid dispersion in a dissolution study using a buffer of pH 6.8. This characteristic was unchanged after a storage test at high temperature and high humidity. The inhibitory effect of HPMCAS on recrystallization of NP from a supersaturated solution was the greatest among all the polymers examined. Further, the drug release pattern could be modulated by altering the ratio of succinoyl and acetyl moieties in the polymer chain. Our results indicate that HPMCAS is an attractive candidate for use as a carrier in solid dispersions. PMID:15000425

  4. The quantitation of buffering action I. A formal & general approach

    PubMed Central

    Schmitt, Bernhard M

    2005-01-01

    Background Although "buffering" as a homeostatic mechanism is a universal phenomenon, the quantitation of buffering action remains controversial and problematic. Major shortcomings are: lack of a buffering strength unit for some buffering phenomena, multiple and mutually incommensurable units for others, and lack of a genuine ratio scale for buffering strength. Here, I present a concept of buffering that overcomes these shortcomings. Theory Briefly, when, for instance, some "free" H+ ions are added to a solution (e.g. in the form of strong acid), buffering is said to be present when not all H+ ions remain "free" (i.e., bound to H2O), but some become "bound" (i.e., bound to molecules other than H2O). The greater the number of H+ ions that become "bound" in this process, the greater the buffering action. This number can be expressed in two ways: 1) With respect to the number of total free ions added as "buffering coefficient b", defined in differential form as b = d(bound)/d(total). This measure expresses buffering action from nil to complete by a dimensionless number between 0 and 1, analogous to probabilites. 2) With respect to the complementary number of added ions that remain free as "buffering ratio B", defined as the differential B = d(bound)/d(free). The buffering ratio B provides an absolute ratio scale, where buffering action from nil to perfect corresponds to dimensionless numbers between 0 and infinity, and where equal differences of buffering action result in equal intervals on the scale. Formulated in purely mathematical, axiomatic form, the concept reveals striking overlap with the mathematical concept of probability. However, the concept also allows one to devise simple physical models capable of visualizing buffered systems and their behavior in an exact yet intuitive way. Conclusion These two measures of buffering action can be generalized easily to any arbitrary quantity that partitions into two compartments or states, and are thus suited to serve as standard units for buffering action. Some exemplary treatments of classical and non-classical buffering phenomena are presented in the accompanying paper. PMID:15769288

  5. 4-Carbamoylpiperidinium acetate monohydrate.

    PubMed

    Smith, Graham; Wermuth, Urs D

    2010-01-01

    In the structure of the title compound, C(6)H(13)N(2)O(+)·C(2)H(3)O(2) (-)·H(2)O, the amide H atoms of the cations form centrosymmetric cyclic hydrogen-bonding associations incorporating two water mol-ecules [graph set R(4) (2)(8)], which are conjoint with cyclic water-bridged amide-amide associations [R(4) (4)(12)] and larger R(4) (4)(20) associations involving the water mol-ecule and the acetate anions, which bridge through the piperidinium H-bond donors, giving an overall three-dimensional framework structure. PMID:21589458

  6. 4-Carbamoylpiperidinium acetate monohydrate

    PubMed Central

    Smith, Graham; Wermuth, Urs D.

    2010-01-01

    In the structure of the title compound, C6H13N2O+·C2H3O2 ?·H2O, the amide H atoms of the cations form centrosymmetric cyclic hydrogen-bonding associations incorporating two water mol­ecules [graph set R 4 2(8)], which are conjoint with cyclic water-bridged amide–amide associations [R 4 4(12)] and larger R 4 4(20) associations involving the water mol­ecule and the acetate anions, which bridge through the piperidinium H-bond donors, giving an overall three-dimensional framework structure. PMID:21589458

  7. Virginia Tech - Buffer Pool

    NSDL National Science Digital Library

    Cliff Shaffer

    Allows user to select from FIFO, LRU, and LFU page replacement strategies. User then gives a series of page requests and the AV shows the decisions made regarding page replacement. Simple to use, clearly shows the process. It would be nice if the user could pick the size of the backing memory and the buffer pool. Recommended as lecture aide, standalone, self-study suppliment to tutorial or lecture.

  8. XP13512 [(+/-)-1-([(alpha-isobutanoyloxyethoxy)carbonyl] aminomethyl)-1-cyclohexane acetic acid], a novel gabapentin prodrug: I. Design, synthesis, enzymatic conversion to gabapentin, and transport by intestinal solute transporters.

    PubMed

    Cundy, Kenneth C; Branch, Russell; Chernov-Rogan, Tania; Dias, Tracy; Estrada, Toño; Hold, Karin; Koller, Kerry; Liu, Xiaoli; Mann, Adam; Panuwat, Matt; Raillard, Stephen P; Upadhyay, Shubhra; Wu, Quincey Q; Xiang, Jia-Ning; Yan, Hui; Zerangue, Noa; Zhou, Cindy X; Barrett, Ronald W; Gallop, Mark A

    2004-10-01

    Gabapentin is thought to be absorbed from the intestine of humans and animals by a low-capacity solute transporter localized in the upper small intestine. Saturation of this transporter at doses used clinically leads to dose-dependent pharmacokinetics and high interpatient variability, potentially resulting in suboptimal drug exposure in some patients. XP13512 [(+/-)-1-([(alpha-isobutanoyloxyethoxy)carbonyl] aminomethyl)-1-cyclohexane acetic acid] is a novel prodrug of gabapentin designed to be absorbed throughout the intestine by high-capacity nutrient transporters. XP13512 was stable at physiological pH but rapidly converted to gabapentin in intestinal and liver tissue from rats, dogs, monkeys, and humans. XP13512 was not a substrate or inhibitor of major cytochrome P450 isoforms in transfected baculosomes or liver homogenates. The separated isomers of XP13512 showed similar cleavage in human tissues. The prodrug demonstrated active apical to basolateral transport across Caco-2 cell monolayers and pH-dependent passive permeability across artificial membranes. XP13512 inhibited uptake of (14)C-lactate by human embryonic kidney cells expressing monocarboxylate transporter type-1, and direct uptake of prodrug by these cells was confirmed using liquid chromatography-tandem mass spectrometry. XP13512 inhibited uptake of (3)H-biotin into Chinese hamster ovary cells overexpressing human sodium-dependent multivitamin transporter (SMVT). Specific transport by SMVT was confirmed by oocyte electrophysiology studies and direct uptake studies in human embryonic kidney cells after tetracycline-induced expression of SMVT. XP13512 is therefore a substrate for several high-capacity absorption pathways present throughout the intestine. Therefore, administration of the prodrug should result in improved gabapentin bioavailability, dose proportionality, and colonic absorption compared with administration of gabapentin. PMID:15146028

  9. Acid Rain Experiments: Soil Buffering

    NSDL National Science Digital Library

    This experiment will help students understand that soil sometimes contains substances, like limestone, that buffer acids or bases, and that some salts in soil may also act as buffers. They will collect soil samples from their lawn, garden, or school and look for buffering effects by observing the pH change of an acid mixture poured through the samples. If the water collected from the sample is less acidic than the original mixture, then the soil is buffering some of the acid. If it does not change, then the soil may not be capable of buffering acids.

  10. The Endogenous Calcium Buffer and the Time Course of Transducer Adaptation in Auditory Hair Cells

    Microsoft Academic Search

    A. J. Ricci; R. Fettiplace

    1998-01-01

    anism that is sensitive to the level of internal calcium buffer. We have used the properties of transducer adaptation to compare the effects of exogenous calcium buffers in the patch electrode solution with those of the endogenous buffer assayed with perforated-patch recording. The endogenous buffer of the hair bundle was equivalent to 0.1-0.4 mM BAPTA and, in a majority of

  11. Oral acetate supplementation after prolonged moderate intensity exercise enhances early muscle glycogen resynthesis in horses.

    PubMed

    Waller, Amanda P; Geor, Raymond J; Spriet, Lawrence L; Heigenhauser, George J F; Lindinger, Michael I

    2009-08-01

    Oral acetate supplementation enhances glycogen synthesis in some mammals. However, while acetate is a significant energy source for skeletal muscle at rest in horses, its effects on glycogen resynthesis are unknown. We hypothesized that administration of an oral sodium acetate-acetic acid solution with a typical grain and hay meal after glycogen-depleting exercise would result in a rapid appearance of acetate in blood with rapid uptake by skeletal muscle. It was further hypothesized that acetate taken up by muscle would be converted to acetyl CoA (and acetylcarnitine), which would be metabolized to CO2 and water via the tricarboxylic acid cycle, generating ATP within the mitochondria and thereby allowing glucose taken up by muscle to be preferentially incorporated into glycogen. Gluteus medius biopsies and jugular venous blood were sampled from nine exercise-conditioned horses on two separate occasions, at rest and for 24 h following a competition exercise test (CET) designed to simulate the speed and endurance test of a 3 day event. After the CETs, horses were allowed water ad libitum and either 8 l of a hypertonic sodium acetate-acetic acid solution via nasogastric gavage followed by a typical hay-grain meal (acetate treatment) or a hay-grain meal alone (control treatment). The CET significantly decreased muscle glycogen concentration by 21 and 17% in the acetate and control treatments, respectively. Acetate supplementation resulted in a rapid and sustained increase in plasma [acetate]. Skeletal muscle [acetyl CoA] and [acetylcarnitine] were increased at 4 h of recovery in the acetate treatment, suggesting substantial tissue extraction of the supplemented acetate. Acetate supplementation also resulted in an enhanced rate of muscle glycogen resynthesis during the initial 4 h of the recovery period compared with the control treatment; however, by 24 h of recovery there was no difference in glycogen replenishment between trials. It is concluded that oral acetate could be an alternative energy source in the horse. PMID:19429643

  12. Design and synthesis of novel isoelectric buffers 

    E-print Network

    Lalwani, Sanjiv Kumar Shankerdass

    2006-04-12

    of the appropriate acrylamido weak acid or weak base derivatives (the buffering species) and an acrylamido strong acid or strong base derivative (the titrating species) [10,11], commercially available as Immobilines [12]. These Immobiline-based isoelectric... flow parallel to the gel surface. The anti-convective barrier formed by the gel is then breached and bulk mixing of the solutions from different chambers occurs. The acrylamido acidic and basic side groups also hydrolyze off from the gel, leaving...

  13. Facile hydrolysis and alcoholysis of palladium acetate.

    PubMed

    Bedford, Robin B; Bowen, John G; Davidson, Russell B; Haddow, Mairi F; Seymour-Julen, Annabelle E; Sparkes, Hazel A; Webster, Ruth L

    2015-05-26

    Palladium(II) acetate is readily converted into [Pd3 (?(2) -OH)(OAc)5 ] (1) in the presence of water in a range of organic solvents and is also slowly converted in the solid state. Complex 1 can also be formed in nominally anhydrous solvents. Similarly, the analogous alkoxide complexes [Pd3 (?(2) -OR)(OAc)5 ] (3) are easily formed in solutions of palladium(II) acetate containing a range of alcohols. An examination of a representative Wacker-type oxidation shows that the Pd-OH complex 1 and a related Pd-oxo complex 4 can be excluded as potential catalytic intermediates in the absence of exogenous water. PMID:25865439

  14. In vitro hydrolysis of poly(L-lactide) crystalline residues as extended-chain crystallites. Part I: long-term hydrolysis in phosphate-buffered solution at 37 degrees C.

    PubMed

    Tsuji, Hideto; Ikarashi, Kensaku

    2004-11-01

    Poly(L-lactide) (PLLA) crystalline residues or extended-chain crystallites containing a trace amount of chains in an amorphous state were prepared by hydrolysis of crystallized PLLA films in a phosphate-buffered solution (PBS) at 97 degrees C for 40h. Their in vitro hydrolysis behavior and mechanism were investigated in PBS at 37 degrees C for the periods of time up to 512 days using gel permeation chromatography (GPC), gravimetry, differential scanning calorimetry, and wide angle X-ray diffractometry. The GPC results showed that the hydrolysis of the crystalline residues proceeded from their surface composed of very short chains with a free end along the chain direction but the hydrolysis from their lateral surface could not be traced. The average hydrolysis rates of PLLA crystalline residues estimated from the changes of number-average and peak top molecular weights (M(n) and M(t), respectively) were 5.31 and 5.01gmol(-1)day(-1), respectively. Such low hydrolysis rates mean that the PLLA crystalline residues can remain for a long period such as ca. 2x10(3) days (ca. 5.5 years) in the human body even after PLLA loses its functions as biomaterials. The increased melting temperature (T(m)) and crystallinity (X(c)) (in 320 days), and the decreased half-widths of X-ray diffraction peaks (in 320 days) during hydrolysis were attributed to the decreased lattice disorder of the PLLA crystalline residues. On the other hand, the decreased X(c) for the hydrolysis period exceeding 320 days was ascribed to the decreased thickness or M(n) of the crystalline residues, which increased the effect of the surface having a large surface energy. PMID:15142725

  15. Specific ion and buffer effects on protein-protein interactions of a monoclonal antibody.

    PubMed

    Roberts, D; Keeling, R; Tracka, M; van der Walle, C F; Uddin, S; Warwicker, J; Curtis, R

    2015-01-01

    Better predictive ability of salt and buffer effects on protein-protein interactions requires separating out contributions due to ionic screening, protein charge neutralization by ion binding, and salting-in(out) behavior. We have carried out a systematic study by measuring protein-protein interactions for a monoclonal antibody over an ionic strength range of 25 to 525 mM at 4 pH values (5, 6.5, 8, and 9) in solutions containing sodium chloride, calcium chloride, sodium sulfate, or sodium thiocyante. The salt ions are chosen so as to represent a range of affinities for protein charged and noncharged groups. The results are compared to effects of various buffers including acetate, citrate, phosphate, histidine, succinate, or tris. In low ionic strength solutions, anion binding affinity is reflected by the ability to reduce protein-protein repulsion, which follows the order thiocyanate > sulfate > chloride. The sulfate specific effect is screened at the same ionic strength required to screen the pH dependence of protein-protein interactions indicating sulfate binding only neutralizes protein charged groups. Thiocyanate specific effects occur over a larger ionic strength range reflecting adsorption to charged and noncharged regions of the protein. The latter leads to salting-in behavior and, at low pH, a nonmonotonic interaction profile with respect to sodium thiocyanate concentration. The effects of thiocyanate can not be rationalized in terms of only neutralizing double layer forces indicating the presence of an additional short-ranged protein-protein attraction at moderate ionic strength. Conversely, buffer specific effects can be explained through a charge neutralization mechanism, where buffers with greater valency are more effective at reducing double layer forces at low pH. Citrate binding at pH 6.5 leads to protein charge inversion and the formation of attractive electrostatic interactions. Throughout the report, we highlight similarities in the measured protein-protein interaction profiles with previous studies of globular proteins and of antibodies providing evidence that the behavior will be common to other protein systems. PMID:25389571

  16. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Sodium acetate. 582.1721 Section 582...Purpose Food Additives § 582.1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is generally...

  17. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Sodium acetate. 582.1721 Section 582...Purpose Food Additives § 582.1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is generally...

  18. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Sodium acetate. 582.1721 Section 582...Purpose Food Additives § 582.1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is generally...

  19. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Sodium acetate. 582.1721 Section 582...Purpose Food Additives § 582.1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is generally...

  20. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight. (2...C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by weight....

  1. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight. (2...C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by weight....

  2. Ulipristal acetate for emergency contraception.

    PubMed

    Russo, J A; Creinin, M D

    2010-09-01

    Ulipristal acetate is a progesterone receptor modulator. As an emergency contraceptive, a 30-mg micronized formulation is effective for use up to 120 h from unprotected sexual intercourse. Ulipristal acetate acts as an antagonist of the progesterone receptor at the transcriptional level and a competitive antagonist of glucocorticoid receptor function. In contrast to other contraceptives, it has little effect on sex hormone-binding globulin. Although a single small study demonstrated some potential endometrial effects after ulipristal acetate administration, the clinical relevance of these findings is unclear. The incidence of adverse events in clinical trials for emergency contraception has typically been minimal, with one study showing a higher than expected incidence of nausea upon ulipristal acetate use. Ulipristal acetate, like other emergency contraceptive products, can lengthen the time to the next expected menstruation. Ulipristal acetate may have several advantages over currently approved emergency contraceptives. When compared to levonorgestrel, ulipristal acetate maintains its efficacy for a full 120 h, whereas levonorgestrel formulations have declining efficacy over that time frame. Moreover, although the copper intrauterine device (IUD) is highly effective as an emergency contraceptive, accessibility is an issue since the IUD requires a skilled provider for insertion. PMID:20967297

  3. Ulipristal acetate: contraceptive or contragestive?

    PubMed

    Keenan, Jeffrey A

    2011-06-01

    Ulipristal acetate is the first selective progesterone receptor modulator approved for postcoital contraception in the US. It appears to be significantly more effective in inhibition of ovulation than other forms of emergency contraception. However, ulipristal acetate is structurally similar to mifepristone, and several lines of evidence suggest that a postfertilization mechanism of action is also operative. This mechanism of action is considered to be contragestive versus contraceptive. Ulipristal acetate administration is contraindicated in a known or suspected pregnancy; however, it could quite possibly be used as an effective abortifacient. Health-care providers should inform patients of the possibility of both mechanisms of action with use of this drug. PMID:21666088

  4. Mechanisms of buffer therapy resistance

    PubMed Central

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

    2014-01-01

    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. PMID:24862761

  5. Antibiofilm Properties of Acetic Acid

    PubMed Central

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup; Nielsen, Anne K.; Johansen, Helle Krogh; Homøe, Preben; Høiby, Niels; Givskov, Michael; Kirketerp-Møller, Klaus

    2015-01-01

    Bacterial biofilms are known to be extremely tolerant toward antibiotics and other antimicrobial agents. These biofilms cause the persistence of chronic infections. Since antibiotics rarely resolve these infections, the only effective treatment of chronic infections is surgical removal of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms. PMID:26155378

  6. Methanogenesis from acetate: enrichment studies.

    PubMed

    Baresi, L; Mah, R A; Ward, D M; Kaplan, I R

    1978-07-01

    An acetate enrichment culture was initiated by inoculating anaerobic sludge from a mesophilic methane digestor into a mineral salts medium with calcium acetate as the sole carbon and energy source. This enrichment was maintained indefinitely by weekly transfer into medium of the same composition. A study of this enrichment disclosed an unexpected age-dependent inhibition of methanogenesis by H2 and formate which apparently differed from the inhibition by chloroform and benzyl viologen. This age-dependent inhibition indicated that microbial interactions of the mixed enrichment population may play a regulatory role in methane formation. Futhermore, stimulation of methanogenesis in the acetate enrichment by addition of yeast extract showed a nutrient limitation which indicated that syntrophic interactions leading to formation of growth factors may also occur. A model is presented to illustrate the possible interrelationships between methanogenic and nonmethanogenic bacteria in their growth and formation of methane and carbon dioxide from acetate. PMID:697356

  7. Counterflow immunoisotachophoresis on cellulose acetate membranes.

    PubMed

    Abelev, G I; Karamova, E R

    1984-11-01

    Discontinuous electrophoresis on cellulose acetate membranes with the use of 0.06 M Tris-HCl (pH 6.7) as the leading electrolyte and 0.012 M Tris-beta-alanine (pH 8.6) as the terminating one results in concentration of the proteins present in the system on the Cl-/beta-alanine- boundary. If the antigen solution is placed in a "pocket" ahead of the moving boundary, a counterflow to the cathode arises due to electroendosmosis. At constant voltage the migration rate of the boundary drops and that of electroendosmosis does not change until they become equal. In such a stationary position, the antigen-containing solution is passing through the Cl-/beta-alanine- boundary to the cathode, while all the proteins are completely "absorbed" on the boundary as highly concentrated bands. Addition of ampholytes to the antigen solution contributes to the isotachophoretic separation of a protein mixture on the strip. The concentrated and separated antigens can be revealed by immunofixation, immunodiffusion, or crossed immunoelectrophoresis in gel. The technique is approximately 100 times more sensitive compared to the usual immunodiffusion and immunoelectrophoresis methods on cellulose acetate membranes, and is applicable to the detection of trace amounts of antigens in the urine, liquor, amniotic fluid, tears, and other biological fluids with low protein contents. PMID:6528978

  8. Effects of Environmental Parameters on the Formation and Turnover of Acetate by Forest Soils

    PubMed Central

    Kusel, K.; Drake, H. L.

    1995-01-01

    The capacity to form acetate from endogenous matter was a common property of diverse forest soils when incubated under anaerobic conditions. At 15 to 20(deg)C, acetate synthesis occurred without appreciable delay when forest soils were incubated as buffered suspensions or in microcosms at various percentages of their maximum water holding capacity. Rates for acetate formation with soil suspensions ranged from 35 to 220 (mu)g of acetate per g (dry weight) of soil per 24 h, and maximal acetate concentrations obtained in soil suspensions were two- to threefold greater than those obtained with soil microcosms at the average water holding capacity of the soil. Cellobiose degradation in soil suspensions yielded H(inf2) as a transient product. Under anaerobic conditions, supplemental H(inf2) and CO(inf2) were directed towards the acetogenic synthesis of acetate, and enrichments yielded a syringate-H(inf2)-consuming acetogenic consortium. At in situ temperatures, acetate was a relatively stable anaerobic end product; however, extended incubation periods induced acetoclastic methanogenesis and sulfate reduction. Higher mesophilic and thermophilic temperatures greatly enhanced the capacity of soils to form methane. Although methanogenic and sulfate-reducing activities under in situ-relevant conditions were negligible, these findings nonetheless demonstrated the occurrence of methanogens and sulfate-reducing bacteria in these aerated terrestrial soils. In contrast to the protracted stability of acetate under anaerobic conditions at 15 to 20(deg)C with unsupplemented soils, acetate formed by forest soils was rapidly consumed in the presence of oxygen and nitrate, and substrate-product stoichiometries indicated that acetate turnover was coupled to oxygen-dependent respiration and denitrification. The collective results suggest that acetate formed under anaerobic conditions might constitute a trophic link between anaerobic and aerobic processes in forest soils. PMID:16535147

  9. Molecular Structure of Acetic acid

    NSDL National Science Digital Library

    2003-06-02

    Acetic Acid commonly associated with vinegar; it is the most commercially important organic acid and is used to manufacture a wide range of chemical products, such as plastics and insecticides. Acetic acid is produced naturally by Aceto bacteria but, except for making vinegar, is usually made through synthetic processes. Ethanoic acid is used as herbicide, as a micro-biocide, as a fungicide and for pH adjustment.

  10. Simultaneous determination of 2-naphthoxyacetic acid and indole-3-acetic acid by first derivation synchronous fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, Xiangxiang; Wan, Yiqun

    2013-07-01

    A simple, rapid, sensitive and selective method for simultaneously determining 2-naphthoxyacetic acid (BNOA) and Indole-3-Acetic Acid (IAA) in mixtures has been developed using derivation synchronous fluorescence spectroscopy based on their synchronous fluorescence. The synchronous fluorescence spectra were obtained with ?? = 100 nm in a pH 8.5 NaH2PO4-NaOH buffer solution, and the detected wavelengths of quantitative analysis were set at 239 nm for BNOA and 293 nm for IAA respectively. The over lapped fluorescence spectra were well separated by the synchronous derivative method. Under optimized conditions, the limits of detection (LOD) were 0.003 ?g/mL for BNOA and 0.012 ?g/mL for IAA. This method is simple and expeditious, and it has been successfully applied to the determination of 2-naphthoxyacetic acid and indole-3-acetic acid in fruit juice samples with satisfactory results. The samples were only filtrated through a 0.45 ?m membrane filter, which was free from the tedious separation procedures. The obtaining recoveries were in the range of 83.88-87.43% for BNOA and 80.76-86.68% for IAA, and the relative standard deviations were all less than 5.0%. Statistical comparison of the results with high performance liquid chromatography Mass Spectrometry (HPLC-MS) method revealed good agreement and proved that there were no significant difference in the accuracy and precision between these two methods.

  11. Degradation of acetic acid with sulfate radical generated by persulfate ions photolysis

    Microsoft Academic Search

    Justine Criquet; Nathalie Karpel Vel Leitner

    2009-01-01

    The photolysis of S2O82- was studied for the removal of acetic acid in aqueous solution and compared with the H2O2\\/UV system. The SO4- radicals generated from the UV irradiation of S2O82- ions yield a greater mineralization of acetic acid than the OH radicals. Acetic acid is oxidized by SO4- radicals without significant formation of intermediate by-products. Increasing system pH results

  12. Oracle Log Buffer Queueing

    SciTech Connect

    Rivenes, A S

    2004-12-08

    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.

  13. Agarose gel electrophoresis Solutions and reagents

    E-print Network

    Abou Elela, Sherif

    to 1L Adjust pH to 8.3 with NaOH or acetic acid Store at RT TBE (5X) Tris 54g EDTA 4.65g Boric Acid 24g ddH2O up to 1L Adjust pH to 8.3 with boric acid Store at RT - Ethidium bromide (EtBr), 10 mg/ml (20) -Electrophoresis buffer: TAE buffer (Tris, acetate, EDTA) 50X, 1L Tris 242g Acetic acid 57,1ml EDTA 100ml ddH2O up

  14. Unusual buffer action of free-standing nanoscopically confined water.

    PubMed

    Liao, Kylin; Xu, Xiaozhou; Du, Xuezhong

    2010-01-15

    The acid-base properties of nanoscopic water confined in the black soap films (BSFs), which were prepared from aqueous solutions of sodium dodecylsulphate (SDS) with the dye neutral red (NR) as a pH probe, were investigated using a combination of UV-vis and FTIR spectroscopy. For the SDS micellar solutions at pH 1.0-9.5 adjusted with HCl/NaOH solutions and at pH 9.4 with ammonium buffered solution, the aqueous core thicknesses in the corresponding BSFs ranged from 2.7 to 6.2 nm, and the nanoscopically confined water exhibits unusual buffer action resistant not only to acidic/alkaline solutions but also to standard buffer solution. In the heavily water-depleted confined zones, it is most likely that charge pairs in proton-transfer reactions could not be formed effectively and proton transfer was prohibited in the absence of sufficient solvating ability. Theoretical analyzes indicated that the buffer action of the nanoscopic water originated from the confinement effect of two charged surfaces of the BSFs. These results might inspire deeper understanding and further studies of biobuffering, enzyme superactivity, acid-catalyzed reactions, and Nafion fuel cell membranes. PMID:19846104

  15. Application Studies of Cellulose Acetate and Polymethylmethacrylate Blend Ultrafiltration Membranes

    Microsoft Academic Search

    S. Vidya; D. Mohan

    2010-01-01

    The preparation of novel membranes based on cellulose acetate and polymethylmethacrylate blends in the absence and presence of the pore former by solution blending and ultrafiltration set up was carried out. The effect of compaction time on pure water flux at higher transmembrane pressure for various polymer compositions of the above blends both in the presence and absence of the

  16. Stabilizing effect of acetate salts and HCO-3 in digestors receiving high levels of glucose.

    PubMed

    Robbins, J E; Armold, M T; Weiel, J E; Runquist, E A

    1983-10-01

    Anaerobic digestors were fed daily with dairy cattle manure (5% total solids) augmented with 0-20 mM glucose and were monitored daily for gas volume and composition and volatile acid content. Propionate accumulated in digestors that were fed glucose at initial digestor concentrations of 10 mM or more. Digestors that received 14-20 mM glucose failed, but identical digestors that received 20 mM glucose plus 10 mM acetate or HCO-3 did not fail. The sparing effect of HCO-3 was primarily buffering and the similar behavior of digestors that received acetate suggest that acetate metabolism perhaps provided additional HCO-3 for buffering. Analyses of H2 and volatile acid concentrations during a 6-8-h period following feeding in digestors fed glucose or glucose plus acetate showed that propionate and H2 accumulated simultaneously and that H2 concentrations were 3 microM or less. Monitoring 13C-labeled glucose metabolism via 13C nuclear magnetic resonance indicated that glucose was primarily converted to lactate and that the major product from lactate was propionate in both glucose and glucose plus acetate fermentations. PMID:6661702

  17. 1,3,5-Tris(phenyl-2-benzimidazole)-benzene cathode buffer layer thickness dependence in solution-processable organic solar cell based on 1,4,8,11,15,18,22,25-octahexylphthalocyanine

    NASA Astrophysics Data System (ADS)

    De Roméo Banoukepa, Gilles; Fujii, Akihiko; Shimizu, Yo; Ozaki, Masanori

    2015-04-01

    Studies on the insertion effects of a cathode buffer layer on bulk heterojunction organic solar cell based on 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2) and 1-(3-methoxy-carbonyl)-propyl-1-1-phenyl-(6,6)C61 (PCBM) by using 1,3,5-tris(phenyl-2-benzimidazole)-benzene (TPBi) as a cathode buffer layer material have been carried out. The external quantum efficiency and the short-circuit current markedly increased, resulting in the enhancement of the power conversion efficiency. The solar cell performance has been discussed from the atomic force microscopy, photoelectron yield spectroscopy and X-ray photoelectron spectroscopy measurements.

  18. Optimal trellis-based buffered compression and fast approximations.

    PubMed

    Ortega, A; Ramchandran, K; Vetterli, M

    1994-01-01

    The authors formalize the description of the buffer-constrained adaptive quantization problem. For a given set of admissible quantizers used to code a discrete nonstationary signal sequence in a buffer-constrained environment, they formulate the optimal solution. They also develop slightly suboptimal but much faster approximations. These solutions are valid for any globally minimum distortion criterion, which is additive over the individual elements of the sequence. As a first step, they define the problem as one of constrained, discrete optimization and establish its equivalence to some of the problems studied in the field of integer programming. Forward dynamic programming using the Viterbi algorithm is shown to provide a way of computing the optimal solution. Then, they provide a heuristic algorithm based on Lagrangian optimization using an operational rate-distortion framework that, with computing complexity reduced by an order of magnitude, approaches the optimally achievable performance. The algorithms can serve as a benchmark for assessing the performance of buffer control strategies and are useful for applications such as multimedia workstation displays, video encoding for CD-ROMs, and buffered JPEG coding environments, where processing delay is not a concern but decoding buffer size has to be minimized. PMID:18291907

  19. LC determination of octreotide acetate in compound formulations of Sandostatin ® and diamorphine hydrochloride

    Microsoft Academic Search

    N Kyaterekera; J. N. A Tettey; G. G Skellern; D. G Watson; J Urie; J. R McDade; H Fielding

    1999-01-01

    The determination of octreotide acetate in compound formulations of Sandostatin® and diamorphine hydrochloride by RP–LC is described. Octreotide acetate, diamorphine hydrochloride and their respective degradants, [des-Thr-ol8]-octreotide and 6-O-acetylmorphine, were baseline resolved using a Lichrospher-60 RP-select B column with a mobile phase composition of acetonitrile\\/phosphate buffer (pH 7.4, 20 mM) (35:65 v\\/v) with UV detection at 210 nm. The method is

  20. Taraxerol acetate at 100 K.

    PubMed

    Billodeaux, D R; Benavides, G A; Fischer, N H; Fronczek, F R

    1999-12-15

    The title triterpene, D-friedoolean-14-en-3 beta-yl acetate, C32H52O2, was isolated from dichloromethane extracts of the roots of common ragweed Ambrosia artemisiifolia. The skeleton contains five fused six-membered rings with an average Csp3-Csp3 bond distance of 1.549 (6) A and one double bond of length 1.348 (6) A. The D and E rings are cis-fused. The compound also contains a beta-oriented acetate group with a C-O distance 1.461 (5) A. PMID:10641284

  1. Solution properties of polygalacturonic acid

    PubMed Central

    Stoddart, R. W.; Spires, I. P. C.; Tipton, K. F.

    1969-01-01

    1. The specimen of polygalacturonic acid used in these studies was shown to contain very little neutral sugar, methyl ester groups or ash, and only residues of galacturonic acid. Its electrophoretic homogeneity was examined in pyridine–acetic acid buffer at pH6·5 and in borate buffer at pH9·2. The distribution of effective particle weights was shown to be fairly narrow. 2. The pH-titration curve of the polymer gave a pK value of 3·7. 3. The interaction of the polymer with Ruthenium Red was studied and titration curves were obtained for the spectral shifts associated with the formation of a complex. 4. Optical-rotatory-dispersion studies showed that the Drude constant, ?c, was dependent on pH. 5. Polygalacturonic acid was shown to display non-Newtonian properties in solution and to have an anomalously high relative specific viscosity at low concentrations. 6. Studies were made of the pH-dependence of the sedimentation coefficient of the polymer. 7. These results are discussed in terms of the structure of the molecule and their relevance to the properties of pectic substances. PMID:5343801

  2. Water-promoted One-step Anodic Acetoxylation of Benzene to Phenyl Acetate with High Selectivity

    NASA Astrophysics Data System (ADS)

    Pei, Juan; Qin, Song; Li, Gui-ying; Hu, Chang-wei

    2011-04-01

    One-step anodic acetoxylation of benzene to phenyl acetate was studied in acetic acid-water solution using a one-compartment electrochemical cell in galvanostatic mode. Compared to the anhydrous system, the addition of water improved the current efficiency for the electro-synthesis of phenyl acetate. The maximum efficiency reached 4.8% with the selectivity of 96% to phenyl acetate when the electrolysis was carried out under the optimal conditions. The investigation also indicated that the concentration of phenyl acetate increased linearly in 12 h and reached 1.07 g/L with the selectivity of 95%. Cyclic voltammetry experiments showed that the adsorption of benzene at Pt anode enhanced by the addition of water was critical to the formation of phenyl acetate. An activated benzene mechanism was proposed for the anodic acytoxylation, and the analysis of gas products demonstrated that Kolbe reaction was the main side reaction.

  3. Buffer Gas Acquisition and Storage

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F.; Lueck, Dale E.; Jennings, Paul A.; Callahan, Richard A.; Delgado, H. (Technical Monitor)

    2001-01-01

    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 CO, 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 (ND, and argon (Ar) through a multiple-membrane system and the individual membranes from room temperature to 193K and 10 kpa to 300 kPa. Concentrations were measured with a gas chromatograph that used a thermoconductivity (TCD) detector with helium (He) as the carrier gas. The general trend as the temperature was lowered was for the membranes to become more selective, In addition, the relative permeation rates between the three gases changed with temperature. The end result was to provide design parameters that could be used to separate CO2 from N2 and Ar.

  4. Understanding the Science Behind Riparian Forest Buffers

    E-print Network

    Liskiewicz, Maciej

    for fish and wildlife, and to benefit landowners and communities. The width of the buffer and the type for funding (for example, a particular buffer width, type of vegetation, and/or length of time the buffer must, and often have different requirements to qualify for funding (for example, wider or narrower buffer widths

  5. The weak spots of saliva buffering tests.

    PubMed

    Buchgraber, Barbara; Kqiku, Lumnije; Reibnegger, Gilbert; Städtler, Peter

    2013-09-01

    Saliva buffering test is in need of improvements. This article illustrates the most commonly used saliva buffering capacity tests and its major problems. Starting with Ericsson and his laboratory buffer capacity test and all the way to Kitasako a lot of issues are to release. The aim of this paper is to put saliva buffering tests up to serious discussion. PMID:24308249

  6. Phytogenic biosynthesis and emission of methyl acetate.

    PubMed

    Jardine, Kolby; Wegener, Frederik; Abrell, Leif; van Haren, Joost; Werner, Christiane

    2014-02-01

    Acetylation of plant metabolites fundamentally changes their volatility, solubility and activity as semiochemicals. Here we present a new technique termed dynamic (13) C-pulse chasing to track the fate of C1-3 carbon atoms of pyruvate into the biosynthesis and emission of methyl acetate (MA) and CO2 . (13) C-labelling of MA and CO2 branch emissions respond within minutes to changes in (13) C-positionally labelled pyruvate solutions fed through the transpiration stream. Strong (13) C-labelling of MA emissions occurred only under pyruvate-2-(13) C and pyruvate-2,3-(13) C feeding, but not pyruvate-1-(13) C feeding. In contrast, strong (13) CO2 emissions were only observed under pyruvate-1-(13) C feeding. These results demonstrate that MA (and other volatile and non-volatile metabolites) derive from the C2,3 atoms of pyruvate while the C1 atom undergoes decarboxylation. The latter is a non-mitochondrial source of CO2 in the light generally not considered in studies of CO2 sources and sinks. Within a tropical rainforest mesocosm, we also observed atmospheric concentrations of MA up to 0.6 ppbv that tracked light and temperature conditions. Moreover, signals partially attributed to MA were observed in ambient air within and above a tropical rainforest in the Amazon. Our study highlights the potential importance of acetyl coenzyme A (CoA) biosynthesis as a source of acetate esters and CO2 to the atmosphere. PMID:23862653

  7. Inhibition of Ice Growth and Recrystallization by Zirconium Acetate and Zirconium Acetate Hydroxide

    PubMed Central

    Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications. PMID:23555701

  8. Inhibition of ice growth and recrystallization by zirconium acetate and zirconium acetate hydroxide.

    PubMed

    Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications. PMID:23555701

  9. Kinetics of Imidazole Catalyzed Ester Hydrolysis: Use of Buffer Dilutions to Determine Spontaneous Rate, Catalyzed Rate, and Reaction Order.

    ERIC Educational Resources Information Center

    Lombardo, Anthony

    1982-01-01

    Described is an advanced undergraduate kinetics experiment using buffer dilutions to determine spontaneous rate, catalyzed rate, and reaction order. The reaction utilized is hydrolysis of p-nitro-phenyl acetate in presence of imidazole, which has been shown to enhance rate of the reaction. (Author/JN)

  10. Good’s buffers as a basis for developing self-buffering and biocompatible ionic liquids for biological research†

    PubMed Central

    Taha, Mohamed; e Silva, Francisca A.; Quental, Maria V.; Ventura, Sónia P. M.; Freire, Mara G.; Coutinho, João A. P.

    2014-01-01

    This work reports a promising approach to the development of novel self-buffering and biocompatible ionic liquids for biological research in which the anions are derived from biological buffers (Good’s buffers, GB). Five Good’s buffers (Tricine, TES, CHES, HEPES, and MES) were neutralized with four suitable hydroxide bases (1-ethyl-3-methylimidazolium, tetramethylammonium, tetraethylammonium, and tetrabutylammonium) producing 20 Good’s buffer ionic liquids (GB-ILs). The presence of the buffering action of the synthesized GB-ILs was ascertained by measuring their pH-profiles in water. Moreover, a series of mixed GB-ILs with wide buffering ranges were formulated as universal buffers. The impact of GB-ILs on bovine serum albumin (BSA), here used as a model protein, is discussed and compared with more conventional ILs using spectroscopic techniques, such as infrared and dynamic light scattering. They appear to display, in general, a greater stabilizing effect on the protein secondary structure than conventional ILs. A molecular docking study was also carried out to investigate on the binding sites of GB-IL ions to BSA. We further used the QSAR-human serum albumin binding model, log K(HSA), to calculate the binding affinity of some conventional ILs/GB-ILs to HSA. The toxicity of the GB and GB-ILs was additionally evaluated revealing that they are non-toxic against Vitro fischeri. Finally, the GB-ILs were also shown to be able to form aqueous biphasic systems when combined with aqueous solutions of inorganic or organic salts, and we tested their extraction capability for BSA. These systems were able to extract BSA with an outstanding extraction efficiency of 100% in a single step for the GB-IL-rich phase, and, as a result, the use of GB-IL-based ABS for the separation and extraction of other added-value biomolecules is highly encouraging and worthy of further investigation. PMID:25729325

  11. Buffer Sizing for Minimum Energy-Delay Product by Using an Approximating Polynomial

    E-print Network

    Pedram, Massoud

    Buffer Sizing for Minimum Energy-Delay Product by Using an Approximating Polynomial Chang Woo Kang to derive sizing rules for buffered chains, which optimize the overall energy-delay product. Categories result in a poor solution in terms of the energy-delay product. The focus of this work is on multi

  12. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the specifications of the Food...

  13. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the specifications of the Food...

  14. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the specifications of the Food...

  15. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the specifications of the Food...

  16. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the specifications of the Food...

  17. Electron tunneling studies of Mn12-Acetate 

    E-print Network

    Ma, Lianxi

    2008-10-10

    We used self-assembling tunnel junctions (SATJs) to study the electron transport through films of the molecular magnets, Mn12-Acetate. Pulse laser deposition (PLD) was used to deposit two monolayers of Mn12-Acetate on ...

  18. Recovery of dilute acetic acid through esterification in a reactive distillation column

    Microsoft Academic Search

    B. Saha; S. P. Chopade; S. M. Mahajani

    2000-01-01

    The recovery of acetic acid from its dilute aqueous solutions is a major problem in both petrochemical and fine chemical industries. The conventional methods of recovery are azeotropic distillation, simple distillation and liquid–liquid extraction. Physical separations such as distillation and extraction suffer from several drawbacks. The esterification of an aqueous solution (30%) of acetic acid with n-butanol\\/iso-amyl alcohol is a

  19. Preparation of transparent, electrically conducting ZnO film from zinc acetate and alkoxide

    Microsoft Academic Search

    Y. Ohya; H. Saiki; Y. Takahashi

    1994-01-01

    Very uniform and transparent zinc oxide thin films doped with aluminium and indium were fabricated by the dip-coating technique using solutions prepared by the ethanolamine method. As starting materials, zinc acetate and zinc n-propoxide were used. Zinc acetate and propoxide are soluble in PriOH in the presence of diethanolamine, although they are hardly soluble without the amine. The prepared solutions

  20. Synthesis and regeneration of lead (IV) acetate

    SciTech Connect

    Boyle, T.J.; Al-Shareef, H.N.; Moore, G.J. [Sandia National Labs., Albuquerque, NM (United States). Advanced Materials Lab.

    1996-11-01

    Lead acetate [Pb(O{sub 2}CMe){sub 4}] was easily synthesized from a warm solution of Pb{sub 3}O{sub 4}, HO{sub 2}CMe and O(OCMe){sub 2} following literature preparations when the appropriate measures to minimize water contamination were followed. Furthermore, Pb(O{sub 2}CMe){sub 4} which has been decomposed (evidenced by the appearance of a purple color due to oxidation) can be regenerated using a similar preparatory route. Introduction of Pb(O{sub 2}CMe){sub 4} from the two routes outlined above into the IMO process for production of PZT thin films gave films with comparable ferroelectric properties to commercially available Pb(O{sub 2}CMe){sub 4} precursors. However, the freshly synthesized material yields PZT films with better properties compared to the recycled material.

  1. 21 CFR 73.2396 - Lead acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a...additive lead acetate may be safely used in cosmetics intended for coloring hair on the scalp...The amount of the lead acetate in the cosmetic shall be such that the lead...

  2. 21 CFR 73.2396 - Lead acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a...additive lead acetate may be safely used in cosmetics intended for coloring hair on the scalp...The amount of the lead acetate in the cosmetic shall be such that the lead...

  3. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

  4. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

  5. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

  6. Influence of glyphosate on the copper dissolution in phosphate buffer

    NASA Astrophysics Data System (ADS)

    Coutinho, C. F. B.; Silva, M. O.; Machado, S. A. S.; Mazo, L. H.

    2007-01-01

    The electrochemical behavior of copper microelectrode in phosphate buffer in the presence of glyphosate was investigated by electrochemical techniques. It was observed that the additions of glyphosate in the phosphate buffer increased the anodic current of copper microelectrode and the electrochemical dissolution was observed. This phenomenon could be associated with the Cu(II) complexation by glyphosate forming a soluble complex. Physical characterization of the surface showed that, in absence of glyphosate, an insoluble layer covered the copper surface; on the other hand, in presence of glyphosate, it was observed a corroded copper surface with the formation of glyphosate complex in solution.

  7. Asymmetric cyclopropanation of ketene silyl acetal with allylic acetate catalyzed by a palladium complex

    Microsoft Academic Search

    Akiharu Satake; Hitomi Kadohama; Hiroyuki Koshino; Tadashi Nakata

    1999-01-01

    The first asymmetric cyclopropanation of ketene silyl acetal with allylic acetate was achieved. New chiral oxazolidinylpyrazole ligands and their ?3-allylpalladium complexes were synthesized. Reaction of cinnamyl acetate with ketene silyl acetal of ethyl isobutylate in the presence of a palladium complex gave a phenyl cyclopropane derivative in 20? 54%ee.

  8. Partner Buffering of Attachment Insecurity

    PubMed Central

    Simpson, Jeffry A.; Overall, Nickola C.

    2014-01-01

    Insecurely attached people have less happy, unstable romantic relationships, but the quality of their relationships should depend on how their partners regulate them. Some partners find ways to buffer (emotionally and behaviorally regulate) insecurely attached individuals, which makes them feel better, behave more constructively, and improves their relationships. Understanding when and how this important interpersonal process works requires a dyad-centered approach. In this article, we describe core tenets of attachment theory and the two forms of attachment insecurity (anxiety and avoidance). We then present the Dyadic Regulation Model of Insecurity Buffering, which explains how and why certain types of buffering behaviors soothe the worries and improve the relationship perceptions and behaviors of anxious or avoidant people. We next review studies of couples trying to resolve major conflicts that illustrate some ways in which partners can successfully buffer the insecure reactions of anxious and avoidant individuals. We conclude by discussing other traits and social contexts to which our model can be applied. PMID:25214722

  9. Intrinsic buffering capacity of feedstuffs

    Microsoft Academic Search

    Sylvie Giger-Reverdin; Christine Duvaux-Ponter; Daniel Sauvant; Olivier Martin; Rudy Müller

    2002-01-01

    Since acidosis is a major pathological risk for ruminants, we have defined a new method for the measurement of the intrinsic buffering capacity (BC) of feeds, by modeling the resistance of a feedstuff to the addition of an acid or a base. We compared results obtained on 24 feedstuffs with a strong acid and a strong base to those measured

  10. Acetic acid induces pH-independent cellular energy depletion in Salmonella enterica.

    PubMed

    Tan, Sin Mei; Lee, Sui Mae; Dykes, Gary A

    2015-03-01

    Weak organic acids are widely used as preservatives and disinfectants in the food industry. Despite their widespread use, the antimicrobial mode of action of organic acids is still not fully understood. This study investigated the effect of acetic acid on the cell membranes and cellular energy generation of four Salmonella strains. Using a nucleic acid/protein assay, it was established that acetic acid did not cause leakage of intracellular components from the strains. A scanning electron microscopy study further confirmed that membrane disruption was not the antimicrobial mode of action of acetic acid. Some elongated Salmonella cells observed in the micrographs indicated a possibility that acetic acid may inhibit DNA synthesis in the bacterial cells. Using an ATP assay, it was found that at a neutral pH, acetic acid caused cellular energy depletion with an ADP/ATP ratio in the range between 0.48 and 2.63 (p<0.05) that was apparent for the four Salmonella strains. We suggest that this effect was probably due solely to the action of undissociated acid molecules. The antimicrobial effect of acetic acid was better under acidic conditions (ADP/ATP ratio of 5.56 ± 1.27; p<0.05), where the role of both pH and undissociated acid molecules can act together. We concluded that the inhibitory effect of acetic acid is not solely attributable to acidic pH but also to undissociated acid molecules. This finding has implication for the use of acetic acid as an antimicrobial against Salmonella on food products, such as chicken meat, which can buffer its pH. PMID:25562466

  11. SEPARATION OF PROTEINS BY ION EXCHANGE AND MEMBRANE CHROMATOGRAPHY: BUFFER COMPOSITION, INTERFERING IMPURITIES AND FOULING CONSIDERATIONS

    E-print Network

    Imam, Tahmina

    2010-01-16

    solution properties (pH, ionic strength, buffer ions) in order to maximize lysozyme purification by a strong cation exchange resin. The interaction of phytic acid, a major impurity, present in transgenic rice extracts, that contributes to decreased lysozyme...

  12. Stacked switched capacitor energy buffer architecture

    E-print Network

    Chen, Minjie, S.M. Massachusetts Institute of Technology

    2012-01-01

    Electrolytic capacitors are often used for energy buffering applications, including buffering between single-phase ac and dc. While these capacitors have high energy density compared to film and ceramic capacitors, their ...

  13. Preparation and characterization of manganese(IV) in aqueous acetic acid.

    PubMed

    Jee, Joo-Eun; Pestovsky, Oleg; Bakac, Andreja

    2010-12-28

    Mn(IV) acetate was generated in acetic acid solutions and characterized by UV-vis spectroscopy, magnetic susceptibility, and chemical reactivity. All of the data are consistent with a mononuclear manganese(IV) species. Oxidation of several substrates was studied in glacial acetic acid (HOAc) and in 95:5 HOAc-H(2)O. The reaction with excess Mn(OAc)(2) produces Mn(OAc)(3) quantitatively with mixed second-order kinetics, k (25.0 °C) = 110 ± 4 M(-1) s(-1) in glacial acetic acid, and 149 ± 3 M(-1) s(-1) in 95% AcOH, ?H(‡) = 55.0 ± 1.2 kJ mol(-1), ?S(‡) = -18.9 ± 4.1 J mol(-1) K(-1). Sodium bromide is oxidized to bromine with mixed second order kinetics in glacial acetic acid, k = 220 ± 3 M(-1) s(-1) at 25 °C. In 95% HOAc, saturation kinetics were observed. PMID:21046054

  14. Diffusivelike buffering and saturation of large rivers.

    PubMed

    Métivier, F

    1999-11-01

    We use mass balance data from Asian rivers together with a first-order diffusive simplification of the St. Venant-Exner equations to characterize river flood plain processes and discuss the reaction of a large model river to a hill slope supply of eroded masses. The simple analytical solution derived for the long-term profile of the river bed shows that (i) the system converges towards a state in which it reacts to perturbations in erosion of the landscape by small-amplitude oscillations around an average "stationary" state, (ii) to have an effective influence on the river plain profile, the perturbations need to have frequencies smaller than the characteristic frequencies of the river system, and (iii) this river buffering might be linked with a possible long-term saturation of the system carrying capacity. PMID:11970481

  15. Throughput Region of Finite-Buffered Networks

    E-print Network

    , IEEE, and Devavrat Shah, Member, IEEE Abstract--Most of the current communication networks, including buffer-size. In this paper, we study the effect of finite buffer-size on the performance of networks theory, flow-controlled networks, scheduling, packet switching, buffered crossbars. Ç 1 INTRODUCTION MOST

  16. Riparian buffers and potentially unstable ground

    Microsoft Academic Search

    Swee May Tang; David R. Montgomery

    1995-01-01

    The spatial coincidence between riparian buffers of various widths and extents and potentially unstable ground was quantified using a physically based model for shallow landslide initiation and GIS for two watersheds on the Olympic Peninsula, Washington, USA. The proportion of the potentially unstable ground in each watershed within riparian buffers is a function of both buffer width and the extent

  17. Distribution of furfuryl alcohol between water and butyl acetate

    SciTech Connect

    Veber, N.V.; Khisamotdinova, A.I.; Tabachova, S.I.

    1985-06-10

    This paper studies the distribution of furfuryl alcohol between water and butyl acetate, which has a comparatively low solubility in water (0.5 g in 100 ml of water), forming a heterogeneous azeotropic mixture. Butyl acetate is capable of giving a hydrogen bond at the carbonyl oxygen with hydroxyl compounds, which serves as the basis for its use as an extraction reagent. The distribution of furfuryl alcohol between water and butyl acetate was studied without salting out agents, and also in the presence of sodium chloride. The experiments were conducted with model solutions of freshly redistilled furfuryl alcohol by shaking equal volumes of the phases in a separatory funnel at 18-20 C. An analysis of furfuryl alcohol in experiments without salting out was performed by a titrimetric method. The results of the distribution of furfuryl alcohol without salting out agents are presented in a table. The distribution of furfuryl alcohol in butyl acetate in the presence of sodium chloride was studied in a smaller range of concentrations.

  18. Biodegradable cellulose acetate nanofiber fabrication via electrospinning.

    PubMed

    Christoforou, Theopisti; Doumanidis, Charalabos

    2010-09-01

    Nanofiber manufacturing is one of the key advancements in nanotechnology today. Over the past few years, there has been a tremendous growth of research activities to explore electrospinning for nanofiber formation from a rich variety of materials. This quite simple and cost effective process operates on the principle that the solution is extracted under the action of a high electric field. Once the voltage is sufficiently high, a charged jet is ejected following a complicated looping trajectory. During its travel, the solvent evaporates leaving behind randomly oriented nanofibers accumulated on the collector. The combination of their nanoscale dimensionality, high surface area, porosity, flexibility and superior strength makes the electrospun fibers suitable for several value-added applications, such as filters, protecting clothes, high performance structures and biomedical devices. In this study biodegradable cellulose acetate (CA) nanofibrous membranes were produced using electrospinning. The device utilized consisted of a syringe equipped with a metal needle, a microdialysis pump, a high voltage supply and a collector. The morphology of the yielded fibers was determined using SEM. The effect of various parameters, including electric field strength, tip-to-collector distance, solution feed rate and composition on the morphological features of the electrospun fibers was examined. The optimum operating conditions for the production of uniform, non-beaded fibers with submicron diameter were also explored. The biodegradable CA nanofiber membranes are suitable as tissue engineering scaffolds and as reinforcements of biopolymer matrix composites in foils by ultrasonic welding methods. PMID:21133179

  19. High effective cytosolic H(+) buffering in mouse cortical astrocytes attributable to fast bicarbonate transport.

    PubMed

    Theparambil, Shefeeq M; Deitmer, Joachim W

    2015-09-01

    Cytosolic H(+) buffering plays a major role for shaping intracellular H(+) shifts and hence for the availability of H(+) for biochemical reactions and acid/base-coupled transport processes. H(+) buffering is one of the prime means to protect the cell from large acid/base shifts. We have used the H(+) indicator dye BCECF and confocal microscopy to monitor the cytosolic H(+) concentration, [H(+) ]i , in cultured cortical astrocytes of wild-type mice and of mice deficient in sodium/bicarbonate cotransporter NBCe1 (NBCe1-KO) or in carbonic anhydrase isoform II (CAII-KO). The steady-state buffer strength was calculated from the amplitude of [H(+) ]i transients as evoked by CO2 /HCO3 (-) and by butyric acid in the presence and absence of CO2 /HCO3 (-) . We tested the hypotheses if, in addition to instantaneous physicochemical H(+) buffering, rapid acid/base transport across the cell membrane contributes to the total, "effective" cytosolic H(+) buffering. In the presence of 5% CO2 /26 mM HCO3 (-) , H(+) buffer strength in astrocytes was increased 4-6 fold, as compared with that in non-bicarbonate, HEPES-buffered solution, which was largely attributable to fast HCO3 (-) transport into the cells via NBCe1, supported by CAII activity. Our results show that within the time frame of determining physiological H(+) buffering in cells, fast transport and equilibration of CO2 /H(+) /HCO3 (-) can make a major contribution to the total "effective" H(+) buffer strength. Thus, "effective" cellular H(+) buffering is, to a large extent, attributable to membrane transport of base equivalents rather than a purely passive physicochemical process, and can be much larger than reported so far. Not only physicochemical H(+) buffering, but also rapid import of HCO3 (-) via the electrogenic sodium-bicarbonate cotransporter NBCe1, supported by carbonic anhydrase II (CA II), was identified to enhance cytosolic H(+) buffer strength substantially. GLIA 2015;63:1581-1594. PMID:25820238

  20. Improving Water Quality With Conservation Buffers

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

    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.

  1. Cobalt (II) chloride promoted formation of honeycomb patterned cellulose acetate films

    Microsoft Academic Search

    Olga Naboka; Anke Sanz-Velasco; Per Lundgren; Peter Enoksson; Paul Gatenholm

    CoCl2 containing honeycomb patterned films were prepared from cellulose acetate (CA)\\/CoCl2\\/acetone solutions by the breath figure method in a wide range of humidities. Size and pore regularity depend on the CA\\/CoCl2 molar ratio and humidity. When replacing CoCl2 with Co(NO3)2 or CoBr2, no formation of ordered porosity in the cellulose acetate films is observed. According to data from scanning electron

  2. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...reporting. (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  3. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...reporting . (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  4. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...reporting . (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  5. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...reporting . (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  6. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...reporting . (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  7. Positron scattering from vinyl acetate

    NASA Astrophysics Data System (ADS)

    Chiari, L.; Zecca, A.; Blanco, F.; García, G.; Brunger, M. J.

    2014-09-01

    Using a Beer-Lambert attenuation approach, we report measured total cross sections (TCSs) for positron scattering from vinyl acetate (C4H6O2) in the incident positron energy range 0.15-50 eV. In addition, we also report an independent atom model with screening corrected additivity rule computation results for the TCSs, differential and integral elastic cross sections, the positronium formation cross section and inelastic integral cross sections. The energy range of these calculations is 1-1000 eV. While there is a reasonable qualitative correspondence between measurement and calculation for the TCSs, in terms of the energy dependence of those cross sections, the theory was found to be a factor of ˜2 larger in magnitude at the lower energies, even after the measured data were corrected for the forward angle scattering effect.

  8. Fungal degradation of polyvinyl acetate.

    PubMed

    García Trejo, A

    1988-08-01

    Certain Aspergillus and Penicillium strains isolated from soil grow well and degrade a commercial sample of polyvinyl acetate (PVA, 4.5 g liter-1) when it is used as the only carbon source. These strains showed an increase in dry weight after 11 days of incubation, along with a depletion of carbohydrates, protein, and deoxyribonucleic acid. This was interpreted as an active turnover of the above metabolites during the degradation. This effect was greatly enhanced by equilibrating the carbon:nitrogen ratio by addition of yeast extract in the original culture. The increase in esterase activity and the loss of viscosity were also considered evidence of the fungal degradation. Isolation of the enzyme was attempted, but unsuccessful. PMID:3181066

  9. Improvements in multimedia data buffering using master/slave architecture

    SciTech Connect

    Sheikh, S.; Ganesan, R. [Widener Univ., PA (United States)

    1996-12-31

    Advances in the networking technology and multimedia technology has necessitated a need for multimedia servers to be robust and reliable. Existing solutions have direct limitations such as I/O bottleneck and reliability of data retrieval. The system can store the stream of incoming data if enough buffer space is available or the mass storage is clearing the buffer data faster than queue input. A single buffer queue is not sufficient to handle the large frames. Queue sizes are normally several megabytes in length and thus in turn will introduce a state of overflow. The system should also keep track of the rewind, fast forwarding, and pause requests, otherwise queue management will become intricate. In this paper, we present a master/slave (server that is designated to monitor the workflow of the complete system. This server holds every other information of slaves by maintaining a dynamic table. It also controls the workload on each of the systems by redistributing request to others or handles the request by itself) approach which will overcome the limitations of today`s storage and also satisfy tomorrow`s storage needs. This approach will maintain the system reliability and yield faster response by using more storage units in parallel. A network of master/slave can handle many requests and synchronize them at all times. Using dedicated CPU and a common pool of queues we explain how queues can be controlled and buffer overflow can be avoided. We propose a layered approach to the buffering problem and provide a read-ahead solution to ensure continuous storage and retrieval of multimedia data.

  10. Modeling epidemic information dissemination on mobile devices with finite buffers

    Microsoft Academic Search

    Christoph Lindemann; Oliver P. Waldhorst

    2005-01-01

    Epidemic algorithms have recently been proposed as an effective solution for disseminating information in large-scale peer-to-peer (P2P) systems and in mobile ad hoc networks (MANET). In this paper, we present a modeling approach for steady-state analysis of epidemic dissemination of information in MANET. As major contribution, the introduced approach explicitly represents the spread of multiple data items, finite buffer capacity

  11. Role of fluoride in accelerating the reactions of dialkylstannylene acetals.

    PubMed

    Lu, Simiao; Boyd, Russell J; Grindley, T Bruce

    2015-03-20

    The most common method for achieving the regioselective monoalkylation of diols involves formation of dialkylstannylene acetals as intermediates. Reactions of dialkylstannylene acetals with alkyl halides are slow, but rates are enhanced by addition of fluoride or other nucleophiles. The mechanism of the fluoride-accelerated alkylation of dialkylstannylene acetals was studied at several levels of theory in the gas phase, in N,N-dimethylformamide (DMF) solution, and in DMF solution in the presence of tetramethylammonium ions. The reactive species were adducts involving addition of fluoride to tin. Under the conditions that most closely simulated experiment, reactions from fluoridated monomers and monofluoridated dimers were calculated to have similar activation energies. In the transition states in the rate-determining steps for the two pathways, carbon-oxygen bond formation was between 60 and 75% complete while tin-oxygen bond cleavage was much less advanced, between 6 and 16% complete. A test of Sn-O bond dissociation indicated that the "Sn-O bond cleavage first" mechanism is not a minimum energy pathway. PMID:25668481

  12. Acetic Acid Can Catalyze Succinimide Formation from Aspartic Acid Residues by a Concerted Bond Reorganization Mechanism: A Computational Study

    PubMed Central

    Takahashi, Ohgi; Kirikoshi, Ryota; Manabe, Noriyoshi

    2015-01-01

    Succinimide formation from aspartic acid (Asp) residues is a concern in the formulation of protein drugs. Based on density functional theory calculations using Ace-Asp-Nme (Ace = acetyl, Nme = NHMe) as a model compound, we propose the possibility that acetic acid (AA), which is often used in protein drug formulation for mildly acidic buffer solutions, catalyzes the succinimide formation from Asp residues by acting as a proton-transfer mediator. The proposed mechanism comprises two steps: cyclization (intramolecular addition) to form a gem-diol tetrahedral intermediate and dehydration of the intermediate. Both steps are catalyzed by an AA molecule, and the first step was predicted to be rate-determining. The cyclization results from a bond formation between the amide nitrogen on the C-terminal side and the side-chain carboxyl carbon, which is part of an extensive bond reorganization (formation and breaking of single bonds and the interchange of single and double bonds) occurring concertedly in a cyclic structure formed by the amide NH bond, the AA molecule and the side-chain C=O group and involving a double proton transfer. The second step also involves an AA-mediated bond reorganization. Carboxylic acids other than AA are also expected to catalyze the succinimide formation by a similar mechanism. PMID:25588215

  13. Effects of sodium lactate and acetic acid derivatives on the quality and sensory characteristics of hot-boned pork sausage patties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sodium lactate and acetic acid derivatives were evaluated for their effects on color retention, microbial growth, and sensory attributes of hot-boned pork sausage patties. Treatments included: (a) sodium lactate (L), (b) buffered vinegar (V), (c) sodium lactate and vinegar mixture (LV), (d) control ...

  14. Manufacturing Ethyl Acetate From Fermentation Ethanol

    NASA Technical Reports Server (NTRS)

    Rohatgi, Naresh K.; Ingham, John D.

    1991-01-01

    Conceptual process uses dilute product of fermentation instead of concentrated ethanol. Low-concentration ethanol, extracted by vacuum from fermentation tank, and acetic acid constitutes feedstock for catalytic reaction. Product of reaction goes through steps that increases ethyl acetate content to 93 percent by weight. To conserve energy, heat exchangers recycle waste heat to preheat process streams at various points.

  15. Buffered Electrochemical Polishing of Niobium

    SciTech Connect

    Gianluigi Ciovati, Hui Tian, Sean Corcoran

    2011-03-01

    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.

  16. Thermodynamic and experimental study of chemical bath deposition of Zn(S,O,OH) buffer layers in basic aqueous ammonia solutions. Cell results with electrodeposited CuIn(S,Se) 2 absorbers

    Microsoft Academic Search

    C. Hubert; N. Naghavi; B. Canava; A. Etcheberry; D. Lincot

    2007-01-01

    This paper presents a thermodynamic study of Chemical Bath Deposition (CBD) of zinc sulphide based films in aqueous ammonia solutions. The aim is a better understanding of ammonia and temperature effects on the deposition conditions and films composition. The formation of solid phases has been predicted by means of the precipitation conditions of ZnO, Zn(OH)2 and ZnS as a function

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

    PubMed

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

    2013-01-15

    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

  18. Riparian buffers and potentially unstable ground

    Microsoft Academic Search

    Swee May Tang; David R. Montgomery

    1995-01-01

    The spatial coincidence between riparian buffers of various widths and extents and potentially unstable ground was quantified\\u000a using a physically based model for shallow landslide initiation and GIS for two watersheds on the Olympic Peninsula, Washington,\\u000a USA. The proportion of the potentially unstable ground in each watershed within riparian buffers is a function of both buffer\\u000a width and the extent

  19. Effect of Organic Acid Additions on the General and Localized Corrosion Susceptibility of Alloy 22 in Chloride Solutions

    SciTech Connect

    Carranza, R M; Giordano, C M; Rodr?guez, M A; Ilevbare, G O; Rebak, R B

    2007-08-28

    Electrochemical studies such as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 (N06022) in 1M NaCl solutions at various pH values from acidic to neutral at 90 C. All the tested material was wrought Mill Annealed (MA). Tests were also performed in NaCl solutions containing weak organic acids such as oxalic, acetic, citric and picric. Results show that the corrosion rate of Alloy 22 was significantly higher in solutions containing oxalic acid than in solutions of pure NaCl at the same pH. Citric and picric acids showed a slightly higher corrosion rate, and acetic acid maintained the corrosion rate of pure chloride solutions at the same pH. Organic acids revealed to be weak inhibitors for crevice corrosion. Higher concentration ratios, compared to nitrate ions, were needed to completely inhibit crevice corrosion in chloride solutions. Results are discussed considering acid dissociation constants, buffer capacity and complex formation constants of the different weak acids.

  20. All-optical buffering for DPSK packets

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  1. SODR Memory Control Buffer Control ASIC

    NASA Technical Reports Server (NTRS)

    Hodson, Robert F.

    1994-01-01

    The Spacecraft Optical Disk Recorder (SODR) is a state of the art mass storage system for future NASA missions requiring high transmission rates and a large capacity storage system. This report covers the design and development of an SODR memory buffer control applications specific integrated circuit (ASIC). The memory buffer control ASIC has two primary functions: (1) buffering data to prevent loss of data during disk access times, (2) converting data formats from a high performance parallel interface format to a small computer systems interface format. Ten 144 p in, 50 MHz CMOS ASIC's were designed, fabricated and tested to implement the memory buffer control function.

  2. Microencapsulation techniques using ethyl acetate as a dispersed solvent: effects of its extraction rate on the characteristics of PLGA microspheres

    Microsoft Academic Search

    Hongkee Sah

    1997-01-01

    Ethyl acetate solvent evaporation and extraction processes were developed to prepare poly(d,l-lactide-co-glycolide) microspheres. The microencapsulation processes first emulsified a polymer-containing ethyl acetate solution with a 1% aqueous polyvinyl alcohol solution (W1) to make an oil-in-water (O\\/W1) emulsion. The O:W1 phase ratio was carefully chosen so as to saturate the W1 by a small proportion of the dispersed solvent and to

  3. Ulipristal acetate in emergency contraception.

    PubMed

    Goldstajn, Marina Sprem; Baldani, Dinka Pavici?; Skrgati?, Lana; Radakovi?, Branko; Vrbi?, Hrvoje; Cani?, Tomislav

    2014-03-01

    Despite the widespread availability of highly effective methods of contraception, unintended pregnancy is common. Unplanned pregnancies have been linked to a range of health, social and economic consequences. Emergency contraception reduces risk of pregnancy after unprotected intercourse, and represents an opportunity to decrease number of unplanned pregnancies and abortions. Emergency contraception pills (ECP) prevent pregnancy by delaying or inhibiting ovulation, without interfering with post fertilization events. If pregnancy has already occurred, ECPs will not be effective, therefore ECPs are not abortificants. Ulipristal acetate (17alpha-acetoxy-11beta-(4N-N,N-dymethilaminophenyl)-19-norpregna--4,9-diene-3,20-dione) is the first drug that was specifically developed and licensed for use as an emergency contraceptive. It is an orally active, synthetic, selective progesterone modulator that acts by binding with high affinity to the human progesterone receptor where it has both antagonist and partial agonist effects. It is a new molecular entity and the first compound in a new pharmacological class defined by the pristal stem. Up on the superior clinical efficacy evidence, UPA has been quickly recognized as the most effective emergency contraceptive pill, and recently recommended as the first prescription choice for all women regardless of the age and timing after intercourse. This article provides literature review of UPA and its role in emergency contraception. PMID:24851646

  4. Pressure-induced aggregation of ?-lactoglobulin in ph 7.0 buffers

    Microsoft Academic Search

    S. Funtenberger; E. Dumay; J. C. Cheftel

    1995-01-01

    Solutions of a ?-lactoglobulin isolate in water, in potassium phosphate buffer (20 or 50 mmol\\/L), and in pressure-resistant buffers, at a protein concentration of 25 g\\/kg and at pH 7.0, were processed at 150, 250, 350 or 450 MPa and 25 °C, for 15 min, then stored at 4 °C, usually for 24 h, before analysis. Bis-Tris (20 or 50

  5. Melatonin: Buffering the Immune System

    PubMed Central

    Carrillo-Vico, Antonio; Lardone, Patricia J.; Álvarez-Sánchez, Nuria; Rodríguez-Rodríguez, Ana; Guerrero, Juan M.

    2013-01-01

    Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed. PMID:23609496

  6. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  7. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  8. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  9. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  10. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  11. Reductive dechlorination of carbon tetrachloride using buffered alkaline ascorbic acid.

    PubMed

    Lin, Ya-Ting; Liang, Chenju

    2015-10-01

    Alkaline ascorbic acid (AA) was recently discovered as a novel in-situ chemical reduction (ISCR) reagent for remediating chlorinated solvents in the subsurface. For this ISCR process, the maintenance of an alkaline pH is essential. This study investigated the possibility of the reduction of carbon tetrachloride (CT) using alkaline AA solution buffered by phosphate and by NaOH. The results indicated that CT was reduced by AA, and chloroform (CF) was a major byproduct at a phosphate buffered pH of 12. However, CT was completely reduced by AA in 2M NaOH without CF formation. In the presence of iron/soil minerals, iron could be reduced by AA and Fe(2+) tends to precipitate on the mineral surface to accelerate CT degradation. A simultaneous transfer of hydrogenolysis and dichloroelimination would occur under phosphate buffered pH 12. This implies that a high alkaline environment is a crucial factor for maintaining the dominant pathway of two electron transfer from dianionic AA to dehydroascorbic acid, and to undergo dichloroelimination of CT. Moreover, threonic acid and oxalic acid were identified to be the major AA decomposition products in alkaline solutions. PMID:25912910

  12. Giant liposomes in physiological buffer using electroformation in a flow chamber

    E-print Network

    Mayer, Michael

    Giant liposomes in physiological buffer using electroformation in a flow chamber Daniel J. Estes April 2005 Abstract We describe a method to obtain giant liposomes (diameter 10­100 Am) in solutions electroformation on ITO electrodes, we formed surface-attached giant liposomes in solutions of glycerol in a flow

  13. Using Input Buffers for Streaming XSLT Processing

    Microsoft Academic Search

    Jana Dvoráková; Filip Zavoral

    2009-01-01

    We present a buffering streaming engine for processing top-down XSLT transformations. It consists of an analyzer and a transformer. The analyzer examines given top-down XSLT and XSD, and gen- erates fragments which identify parts of XSD need to be buffered when XSLT is applied. The fragments are passed to the transformer which processes XSLT on an input XML document conforming

  14. Optimal Buffering for Streaming XPath Evaluation

    Microsoft Academic Search

    Sudarshan S. Chawathe

    We motivate and present a definition of optimal buffering for streaming evaluation of XPath queries. We consider a large fragment of XPath that includes multiple (correlated) subqueries and reverse (up the document tree) axes. We de- scribe a method for XPath evaluation with optimal buffer- ing. We present the results of an experimental evaluation of our methods based on our

  15. NC machining with G-buffer method

    Microsoft Academic Search

    Takafumi Saito; Tokiichiro Takahashi

    1991-01-01

    The G-buffer method is applied to NC machining. A total NC system is created that consists of all essential functions, such as tool path generation, path verification, and feed rate control. Moreover, any combination of object surface and tool shape is acceptable. By utilizing G-buffers created from a parallel projection, the required NC functions are realized as image processing operations.

  16. 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...

  17. Making Fast Buffer Insertion Even Faster via

    E-print Network

    Shi, Weiping "Peter"

    . Lillis, Cheng and Lin [TCAS 96]: O(b2n2) time and space for b buffer types. Shi and Li [DAC 04]: O) time and space for b buffer types. Minimum Cost Lillis, Cheng and Lin [TCAS 96]: pseudo-polynomial time

  18. Buffer Tank Design for Acceptable Control Performance

    E-print Network

    Skogestad, Sigurd

    ), and neutralization vessels. We start with a definition: A buffer tank is a unit where the holdup (volume) is exploited to provide smoother operation. We here focus on buffer tanks for liquids, although most, accumulators, or inventories. 2 #12;In both cases the tank volume is exploited, and a larger volume gives

  19. Ability of subsoils to buffer extremely acidic simulated coal-pile leachates

    SciTech Connect

    Zelmanowitz, S. [Coast Guard Academy, New London, CT (United States); Boyle, W.C.; Armstrong, D.E.; Park, J.K. [Univ. of Wisconsin, Madison, WI (United States)

    1995-11-01

    Coal piles stored directly on soil surfaces may pose a risk of ground-water contamination, particularly when extremely acidic coal-pile leachates, which contain elevated concentrations of heavy metals, are generated. Soil-column experiments were run to evaluate the ability of a sand, a silt loam, and a silt loam amended with 4% CaCO{sub 3} to buffer dilute H{sub 2}SO{sub 4} solutions (pH 3.5 and 1.5) and a synthetic coal-pile leachate (a pH 1.5 H{sub 2}SO{sub 4} solution containing metal sulfate salts). Both silt-loam soils were able to buffer the pH 3.5 H{sub 2}SO{sub 4} solution for the entire leaching period (more than 50 pore volumes), but the sand was not. The buffering capacities of all three soils were insufficient to neutralize pH 1.5 acid and synthetic coal-pile leachates. The sand exhibited the least buffering, and the silt loam at a low flow rate and the silt loam amended with CaCO{sub 3} showed the greatest buffering. The buffering capacities of both silt loam soils were exhausted more rapidly when leached with synthetic coal-pile leachate rather than pH 1.5 H{sub 2}SO{sub 4} solution. This suggests that soil-buffering studies using pure acid solutions may underpredict contamination due to coal-pile leachates. The results indicate that there is a potential for ground-water contamination due to coal-pile storage, particularly where leachates are acidic ad coarse textured soils exist. Coal storage practices should be adopted that protect soils and ground water from acidification and metals contamination.

  20. Characterization of the spherical intermediates and fibril formation of hCT in HEPES solution using solid-state 13C-NMR and transmission electron microscopy.

    PubMed

    Itoh-Watanabe, Hikari; Kamihira-Ishijima, Miya; Kawamura, Izuru; Kondoh, Masashi; Nakakoshi, Masamichi; Sato, Michio; Naito, Akira

    2013-10-21

    Human calcitonin (hCT) is a 32-amino acid peptide hormone that contains an intrachain disulfide bridge between Cys1 and Cys7 and a proline amide at the C-terminus. hCT tends to associate to form a fibril precipitate of the same type as amyloid fibrils, and hence has been studied as a model of amyloid fibril formation. The fibrillation process in N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid (HEPES) solution was examined using transmission electron microscopy. The rate of hCT fibrillation in HEPES solution was much lower than in phosphate buffer and acetic acid solution. Spherical intermediate aggregates (nuclei) were observed during the early stage of fibril formation. Short proto-fibrils appeared on the surface of the spherical intermediates. Subsequently, the spherical intermediates transformed directly into long proto-fibrils, which then elongated into mature hCT fibrils. The fibrillation process was also examined using solid-state (13)C-NMR spectroscopy, which indicated that the fibril structure was a ?-sheet in the central region and a mixture of random coils and ?-sheets at the C-terminus. The kinetics of fibril formation was examined in terms of a two-step autocatalytic reaction mechanism. The first-step nucleation rate (k1) was lower in HEPES solution than in phosphate buffer and acetic acid solution because the half-life of the intermediates is significantly longer in HEPES solution. In contrast, the second-step fibril elongation rate (k2) was similar in HEPES solution and acidic solutions. Specific interaction of HEPES molecules with hCT may stabilize the spherical intermediates and consequently inhibit the fibril elongation process of hCT. PMID:24002168

  1. Acetic Acid Off Gassing in Clamshell Enclosures

    E-print Network

    Brewer, Allison

    2013-01-01

    . This presentation will investigate the use of acid detection strips (A-D strips) to study acetic acid off gassing occurring in custom-made, cloth covered book boxes constructed and used by conservators in research libraries....

  2. Fragrance material review on 4-methylbenzyl acetate.

    PubMed

    McGinty, D; Letizia, C S; Api, A M

    2012-09-01

    A toxicologic and dermatologic review of 4-methylbenzyl acetate when used as a fragrance ingredient is presented. 4-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 4-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, skin irritation, skin sensitization, and elicitation data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414643

  3. Complexation of thorium(IV) with acetate at variable temperatures.

    PubMed

    Rao, Linfeng; Zhang, Zhicheng; Zanonato, PierLuigi; Di Bernardo, Plinio; Bismondo, Arturo; Clark, Sue B

    2004-09-21

    The complexation between Th(IV) and acetate in 1.05 mol kg(-1) NaClO4 was studied at variable temperatures (10, 25, 40, 55 and 70 degrees C). The formation constants of five successive complexes, Th(Ac)j(4-j)+ where Ac = CH3COO- and j = 1-5, and the molar enthalpies of complexation were determined by potentiometry and calorimetry. Extended X-ray absorption fine structure spectroscopy (EXAFS) provided additional information on the complexes in solution. The effect of temperature on the stability of the complexes is discussed in terms of the electrostatic model. PMID:15349159

  4. Methanogenesis from acetate: a nonmethanogenic bacterium from an anaerobic acetate enrichment.

    PubMed

    Ward, D M; Mah, R A; Kaplan, I R

    1978-06-01

    A methanogenic acetate enrichment was initiated by inoculation of an acetate-mineral salts medium with domestic anaerobic digestor sludge and maintained by weekly transfer for 2 years. The enrichment culture contained a Methanosarcina and several obligately anaerobic nonmethanogenic bacteria. These latter organisms formed varying degrees of association with the Methanosarcina, ranging from the nutritionally fastidious gram-negative rod called the satellite bacterium to the nutritionally nonfastidious Eubacterium limosum. The satellite bacterium had growth requirements for amino acids, a peptide, a purine base, vitamin B12, and other B vitamins. Glucose, mannitol, starch, pyruvate, cysteine, lysine, leucine, isoleucine, arginine, and asparagine stimulated growth and hydrogen production. Acetate was neither incorporated nor metabolized by the satellite organism. Since acetate was the sole organic carbon source in the enrichment culture, organism(s) which metabolize acetate (such as the Methanosarcina) must produce substrates and growth factors for associated organisms which do not metabolize acetate. PMID:677881

  5. Isolation of acetic acid bacteria from honey

    Microsoft Academic Search

    Kanlaya Kappeng; Wasu Pathom-aree

    Four thermotolerant acetic acid bacteria designated as CMU1, CMU2, CMU3 and CMU4 were isolated from six honey samples produced by three native bee species in northern Thailand, namely the dwarf honey bee (Apis florea), Asian honey bee (A. cerena) and giant honey bee (A. dorsata). All isolates were tested for their tolerance to acetic acid and ethanol at 30?C and

  6. Nomegestrol acetate/estradiol: in oral contraception.

    PubMed

    Yang, Lily P H; Plosker, Greg L

    2012-10-01

    Nomegestrol acetate/estradiol is a combined oral contraceptive with approval in many countries. This fixed-dose combination tablet contains nomegestrol acetate, a highly selective progestogen, and estradiol, a natural estrogen. It is the first monophasic combined oral contraceptive to contain estradiol, and is taken in 28-day cycles, consisting of 24 active therapy days with 4 placebo days (i.e. 24/4-day cycles). In two large, 1-year, randomized, open-label, multicentre, phase III trials in healthy adult women (aged 18-50 years), nomegestrol acetate/estradiol was at least as effective as drospirenone/ethinylestradiol as contraceptive therapy, as the pregnancy rates in women aged 18-35 years (primary efficacy population) in terms of the Pearl Index (primary endpoint) were numerically lower with nomegestrol acetate/estradiol, although the between-group difference was not statistically significant. In both trials, nomegestrol acetate/estradiol was given in a 24/4-day cycle, and drospirenone/ethinylestradiol was given in a 21/7-day cycle. The criteria for using condoms in case of forgotten doses were less stringent in the nomegestrol acetate/estradiol group than in the drospirenone/ethinylestradiol group. Nomegestrol acetate/estradiol therapy for up to 1 year was generally well tolerated in healthy adult women, with an acceptable tolerability profile in line with that expected for a combined oral contraceptive. The most commonly reported adverse events were acne and abnormal withdrawal bleeding (most often shorter, lighter or absent periods). Overall, compared with drospirenone/ethinylestradiol, nomegestrol acetate/estradiol appeared to be associated with less favourable acne-related outcomes, and shorter, lighter or absent periods. PMID:22950535

  7. Improvement of lipid stability of refrigerated rainbow trout (Oncorhynchus mykiss) fillets by pre-storage ?-tocopherol acetate dipping treatment

    PubMed Central

    Ehsani, Ali; Jasour, Mohammad Sedigh

    2012-01-01

    One of the simplest methods for short-term handling and storage of fish is the refrigeration in combination with dip treatments. This study was conducted to determine the effect of pre-storage ?-tocopherol acetate dipping treatments on lipid stability of refrigerated rainbow trout fillets. Trout fillets were dipped in ?-tocopherol acetate solutions (200 and 500 mg kg-1 flesh) and subsequently stored in a refrigerator at 4 ?C for 12 days. Control samples received no ?-tocopherol acetate during dip treatment. At the end of 0, 3, 6, 9 and 12 days of storage, lipid damage analysis of trout fillets was performed. A continuous notable increase (p < 0.05) in peroxide value (PV), thiobarbituric acid (TBA) and free fatty acid (FFA) was observed for all samples throughout the storage period. Although throughout the storage period the lipid hydrolysis (FFA) of fish fillets was not affected by ?-tocopherol acetate solutions, successful (p < 0.05) inhibition of lipid oxidation (PV and TBA) in refrigerated trout fillets was possible with dip treatment in ?-tocopherol acetate solutions (200 and 500 mg kg-1 flesh). There was no significant (p > 0.05) effect of increasing ?-tocopherol acetate concentration on the lipid deterioration of fish fillets. These results indicated that ?-tocopherol acetate especially at lower level (200 mg kg-1 flesh) was very effective in retarding the lipid oxidation. PMID:25653770

  8. Influence of amino acids, buffers, and ph on the ?-irradiation-induced degradation of alginates.

    PubMed

    Ulset, Ann-Sissel T; Mori, Hideki; Dalheim, Marianne Ø; Hara, Masayuki; Christensen, Bjørn E

    2014-12-01

    Alginate-based biomaterials and medical devices are commonly subjected to ?-irradiation as a means of sterilization, either in the dry state or the gel (hydrated) state. In this process the alginate chains degrade randomly in a dose-dependent manner, altering alginates' material properties. The addition of free radical scavenging amino acids such as histidine and phenylalanine protects the alginate significantly against degradation, as shown by monitoring changes in the molecular weight distributions using SEC-MALLS and determining the pseudo first order rate constants of degradation. Tris buffer (0.5 M), but not acetate, citrate, or phosphate buffers had a similar effect on the degradation rate. Changes in pH itself had only marginal effects on the rate of alginate degradation and on the protective effect of amino acids. Contrary to previous reports, the chemical composition (M/G profile) of the alginates, including homopolymeric mannuronan, was unaltered following irradiation up to 10 kGy. PMID:25412478

  9. Acetate Oxidation Is the Dominant Methanogenic Pathway from Acetate in the Absence of Methanosaetaceae†

    PubMed Central

    Karakashev, Dimitar; Batstone, Damien J.; Trably, Eric; Angelidaki, Irini

    2006-01-01

    The oxidation of acetate to hydrogen, and the subsequent conversion of hydrogen and carbon dioxide to methane, has been regarded largely as a niche mechanism occurring at high temperatures or under inhibitory conditions. In this study, 13 anaerobic reactors and sediment from a temperate anaerobic lake were surveyed for their dominant methanogenic population by using fluorescent in situ hybridization and for the degree of acetate oxidation relative to aceticlastic conversion by using radiolabeled [2-14C]acetate in batch incubations. When Methanosaetaceae were not present, acetate oxidation was the dominant methanogenic pathway. Aceticlastic conversion was observed only in the presence of Methanosaetaceae. PMID:16820524

  10. High stability buffered phase comparator

    NASA Technical Reports Server (NTRS)

    Adams, W. A.; Reinhardt, V. S. (inventors)

    1984-01-01

    A low noise RF signal phase comparator comprised of two high stability driver buffer amplifiers driving a double balanced mixer which operate to generate a beat frequency between the two RF input signals coupled to the amplifiers from the RF sources is described. The beat frequency output from the mixer is applied to a low noise zero crossing detector which is the phase difference between the two RF inputs. Temperature stability is provided by mounting the amplifiers and mixer on a common circuit board with the active circuit elements located on one side of a circuit board and the passive circuit elements located on the opposite side. A common heat sink is located adjacent the circuit board. The active circuit elements are embedded into the bores of the heat sink which slows the effect of ambient temperature changes and reduces the temperature gradients between the active circuit elements, thus improving the cancellation of temperature effects. The two amplifiers include individual voltage regulators, which increases RF isolation.

  11. Sediment retention in rangeland riparian buffers.

    PubMed

    Hook, Paul B

    2003-01-01

    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

  12. Electrophoretic mobilities of erythrocytes in various buffers

    NASA Technical Reports Server (NTRS)

    Plank, L. D.; Kunze, M. E.; Todd, P. W.

    1985-01-01

    The calibration of space flight equipment depends on a source of standard test particles, this test particle of choice is the fixed erythrocyte. Erythrocytes from different species have different electrophoretic mobilities. Electrophoretic mobility depends upon zeta potential, which, in turn depends upon ionic strength. Zeta potential decreases with increasing ionic strength, so cells have high electrophoretic mobility in space electrophoresis buffers than in typical physiological buffers. The electrophoretic mobilities of fixed human, rat, and rabbit erythrocytes in 0.145 M salt and buffers of varying ionic strength, temperature, and composition, to assess the effects of some of the unique combinations used in space buffers were characterized. Several effects were assessed: glycerol or DMSO (dimethylsulfoxide) were considered for use as cryoprotectants. The effect of these substances on erythrocyte electrophoretic mobility was examined. The choice of buffer depended upon cell mobility. Primary experiments with kidney cells established the choice of buffer and cryoprotectant. A nonstandard temperature of EPM in the suitable buffer was determined. A loss of ionic strength control occurs in the course of preparing columns for flight, the effects of small increases in ionic strength over the expected low values need to be evaluated.

  13. A Systematic Approach to the Design of Buffer Tanks

    E-print Network

    Skogestad, Sigurd

    a buffer tank with liquid volume Î ¢ Ñ¿£ , in- ). Zheng and Mahajanam (1998) find the necessary buffer tank volume by optimization and use#12;A Systematic Approach to the Design of Buffer Tanks Audun Faanes £ ½ Sigurd Skogestad

  14. A novel structure of optical buffer

    NASA Astrophysics Data System (ADS)

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

    2005-02-01

    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.

  15. Buffer Repeaters April 20, 1998 1 Buffer Repeaters

    E-print Network

    Harris, David Money

    are widely used to combat the quadratic delay of long on-chip wires. A conven- tional repeater is a CMOS term is the only difference from the inverter-based repeater solution, reflecting the extra delay times larger and the second inverter drives a receiver at the end of the line k times smaller. Thus

  16. Acetate Transport and Utilization in the Rat Brain

    PubMed Central

    Deelchand, Dinesh K.; Shestov, Alexander A.; Koski, Dee M.; U?urbil, Kâmil; Henry, Pierre-Gilles

    2009-01-01

    Acetate, a glial-specific substrate, is an attractive alternative to glucose for the study of neuronal-glial interactions. The present study investigates the kinetics of acetate uptake and utilization in the rat brain in vivo during infusion of [2-13C]acetate using NMR spectroscopy. When plasma acetate concentration was increased, the rate of brain acetate utilization (CMRace) increased progressively and reached close to saturation for plasma acetate concentration > 2-3 mM, whereas brain acetate concentration continued to increase. The Michaelis-Menten constant for brain acetate utilization ( KMutil=0.01±0.14mM) was much smaller than for acetate transport through the blood-brain barrier ( KMt=4.18±0.83mM). The maximum transport capacity of acetate through the blood-brain barrier ( Vmaxt=0.96±0.18?mol/g/min) was nearly two-fold higher than the maximum rate of brain acetate utilization ( Vmaxutil=0.50±0.08?mol/g/min). We conclude that, under our experimental conditions, brain acetate utilization is saturated when plasma acetate concentrations increase above 2-3 mM. At such high plasma acetate concentration, the rate-limiting step for glial acetate metabolism is not the blood-brain barrier, but occurs after entry of acetate into the brain. PMID:19393008

  17. Direct detection of the acetate-forming activity of the enzyme acetate kinase.

    PubMed

    Fowler, Matthew L; Ingram-Smith, Cheryl J; Smith, Kerry S

    2011-01-01

    Acetate kinase, a member of the acetate and sugar kinase-Hsp70-actin (ASKHA) enzyme superfamily, is responsible for the reversible phosphorylation of acetate to acetyl phosphate utilizing ATP as a substrate. Acetate kinases are ubiquitous in the Bacteria, found in one genus of Archaea, and are also present in microbes of the Eukarya. The most well characterized acetate kinase is that from the methane-producing archaeon Methanosarcina thermophila. An acetate kinase which can only utilize PP(i) but not ATP in the acetyl phosphate-forming direction has been isolated from Entamoeba histolytica, the causative agent of amoebic dysentery, and has thus far only been found in this genus. In the direction of acetyl phosphate formation, acetate kinase activity is typically measured using the hydroxamate assay, first described by Lipmann, a coupled assay in which conversion of ATP to ADP is coupled to oxidation of NADH to NAD(+) by the enzymes pyruvate kinase and lactate dehydrogenase, or an assay measuring release of inorganic phosphate after reaction of the acetyl phosphate product with hydroxylamine. Activity in the opposite, acetate-forming direction is measured by coupling ATP formation from ADP to the reduction of NADP(+) to NADPH by the enzymes hexokinase and glucose 6-phosphate dehydrogenase. Here we describe a method for the detection of acetate kinase activity in the direction of acetate formation that does not require coupling enzymes, but is instead based on direct determination of acetyl phosphate consumption. After the enzymatic reaction, remaining acetyl phosphate is converted to a ferric hydroxamate complex that can be measured spectrophotometrically, as for the hydroxamate assay. Thus, unlike the standard coupled assay for this direction that is dependent on the production of ATP from ADP, this direct assay can be used for acetate kinases that produce ATP or PP(i). PMID:22214984

  18. Stability of exenatide in poly(D,L-lactide-co-glycolide) solutions: a simplified investigation on the peptide degradation by the polymer.

    PubMed

    Liang, Rongcai; Zhang, Renyu; Li, Xiang; Wang, Aiping; Chen, Daquan; Sun, Kaoxiang; Liu, Wanhui; Li, Youxin

    2013-11-20

    A solution model can be used to elucidate drug stability issues in a complex system. The aim of this study was to investigate the interaction between poly(D,L-lactide-co-glycolide) (PLGA) and exenatide in organic solvent-acetate buffer saline (ABS) solutions. The effect of solvent composition on exenatide stability was investigated first. In the selected 90:10 dimethyl sulfoxide (DMSO):ABS solution, exenatide stability was examined as a function of PLGA comonomer ratios, molecular weight (Mw) and concentrations. The specific rotation analysis and second derivative UV absorbance spectroscopy were used to monitor the variation of exenatide higher order structure. The effect of ABS pH on the interaction was also investigated. Exenatide degradation products were characterized by HPLC-MS/MS. It was found that exenatide was relatively stable in glacial acetic acid (HAc)-ABS solutions, whereas DMSO content had a strong influence on the conformation state and stability of exenatide. PLGA 50:50 promoted exenatide degradation more than PLGA 75:25 and poly(D,L-lactide) (PLA). Lower Mw and higher concentration of PLGA were beneficial for exenatide degradation. Exenatide was more stable in 90:10 DMSO:ABS (pH 3.0) solution than in 90:10 DMSO:ABS (pH 4.5 and 3.0) solutions during the incubation. HPLC-MS/MS analysis of exenatide demonstrated that acylation was the main degradation route of the peptide. PMID:23994054

  19. Redox buffered hydrofluoric acid etchant for the reduction of galvanic attack during release etching of MEMS devices having noble material films

    SciTech Connect

    Hankins, Matthew G. (Albuquerque, NM)

    2009-10-06

    Etchant solutions comprising a redox buffer can be used during the release etch step to reduce damage to the structural layers of a MEMS device that has noble material films. A preferred redox buffer comprises a soluble thiophosphoric acid, ester, or salt that maintains the electrochemical potential of the etchant solution at a level that prevents oxidation of the structural material. Therefore, the redox buffer preferentially oxidizes in place of the structural material. The sacrificial redox buffer thereby protects the exposed structural layers while permitting the dissolution of sacrificial oxide layers during the release etch.

  20. Synthesis of strontium bismuth niobate (SrBi 2Nb 2O 9) using an aqueous acetate–citrate precursor gel: thermal decomposition and phase formation

    Microsoft Academic Search

    D. Nelis; D. Mondelaers; G. Vanhoyland; A. Hardy; K. Van Werde; H. Van den Rul; M. K. Van Bael; J. Mullens; L. C. Van Poucke; J. D’Haen

    2005-01-01

    An aqueous solution–gel route was developed for the preparation of the ferroelectric material strontium bismuth niobate (SrBi2Nb2O9, SBN). Starting from aqueous Bi3+-acetate and Sr2+-acetate solutions and an aqueous peroxo-citrato-Nb5+-precursor solution, this method offers a low-cost and environmentally friendly alternative to the conventional sol–gel techniques. With regard to the deposition of thin films, it is important to gain insight in the

  1. An acetate switch regulates stress erythropoiesis.

    PubMed

    Xu, Min; Nagati, Jason S; Xie, Jian; Li, Jiwen; Walters, Holly; Moon, Young-Ah; Gerard, Robert D; Huang, Chou-Long; Comerford, Sarah A; Hammer, Robert E; Horton, Jay D; Chen, Rui; Garcia, Joseph A

    2014-09-01

    The hormone erythropoietin (EPO), which is synthesized in the kidney or liver of adult mammals, controls erythrocyte production and is regulated by the stress-responsive transcription factor hypoxia-inducible factor-2 (HIF-2). We previously reported that the lysine acetyltransferase CREB-binding protein (CBP) is required for HIF-2? acetylation and efficient HIF-2-dependent EPO induction during hypoxia. We now show that these processes require acetate-dependent acetyl CoA synthetase 2 (ACSS2). In human Hep3B hepatoma cells and in EPO-generating organs of hypoxic or acutely anemic mice, acetate levels rise and ACSS2 is required for HIF-2? acetylation, CBP-HIF-2? complex formation, CBP-HIF-2? recruitment to the EPO enhancer and efficient induction of EPO gene expression. In acutely anemic mice, acetate supplementation augments stress erythropoiesis in an ACSS2-dependent manner. Moreover, in acquired and inherited chronic anemia mouse models, acetate supplementation increases EPO expression and the resting hematocrit. Thus, a mammalian stress-responsive acetate switch controls HIF-2 signaling and EPO induction during pathophysiological states marked by tissue hypoxia. PMID:25108527

  2. A mammalian acetate switch regulates stress erythropoiesis

    PubMed Central

    Xu, Min; Nagati, Jason S.; Xie, Jian; Li, Jiwen; Walters, Holly; Moon, Young-Ah; Gerard, Robert D.; Huang, Chou-Long; Comerford, Sarah A.; Hammer, Robert E.; Horton, Jay D.; Chen, Rui; Garcia, Joseph A.

    2014-01-01

    Endocrine erythropoietin (Epo), which is synthesized in the kidney or liver of adult mammals, controls erythrocyte production and is regulated by the stress-responsive transcription factor Hypoxia Inducible Factor 2 (HIF-2). We previously reported that the lysine acetyltransferase Cbp is required for HIF-2? acetylation and efficient HIF-2 dependent Epo induction during hypoxia. We now show these processes require acetate-dependent acetyl CoA synthetase 2 (Acss2). In Hep3B hepatoma cells and in Epo-generating organs of hypoxic or acutely anemic mice, acetate levels increase and Acss2 is required for HIF-2? acetylation, Cbp/HIF-2? complex formation and recruitment to the Epo enhancer, and efficient Epo induction. In acutely anemic mice, acetate supplementation augments stress erythropoiesis in an Acss2-dependent manner. In acquired and genetic chronic anemia mouse models, acetate supplementation also increases Epo expression and resting hematocrits. Thus, a mammalian stress-responsive acetate switch controls HIF-2 signaling and Epo induction during pathophysiological states marked by tissue hypoxia. PMID:25108527

  3. Controlled Chemical Doping of Semiconductor Nanocrystals Using Redox Buffers

    SciTech Connect

    Engel, Jesse H.; Surendranath, Yogesh; Alivisatos, Paul

    2013-07-09

    Semiconductor nanocrystal solids are attractive materials for active layers in next-generation optoelectronic devices; however, their efficient implementation has been impeded by the lack of precise control over dopant concentrations. Herein we demonstrate a chemical strategy for the controlled doping of nanocrystal solids under equilibrium conditions. Exposing lead selenide nanocrystal thin films to solutions containing varying proportions of decamethylferrocene and decamethylferrocenium incrementally and reversibly increased the carrier concentration in the solid by 2 orders of magnitude from their native values. This application of redox buffers for controlled doping provides a new method for the precise control of the majority carrier concentration in porous semiconductor thin films.

  4. Photo- and thermal degradation of piroxicam in aqueous solution.

    PubMed

    Aminuddin, M; Nazim, U; Ahmad, I

    2011-07-01

    Light and temperature have considerable effect on the degradation of piroxicam in aqueous solutions. The pH and acetate buffer ions also affect the degradation process. The apparent first-order rate constants for the photochemical and thermal degradation of piroxicam have been determined as 2.04-10.01 and 0.86-3.06×10(-3) min(-1), respectively. The first-order plots for the degradation of piroxicam showed good linearity within a range of 20-50% loss of piroxicam at pH 2.0-12.0. The rate-pH profile for the photodegradation of piroxicam is a U-shaped curve and for the thermal degradation a bell-shaped curve in the pH range of 2.0-12.0. The thermal degradation of piroxicam was maximum around pH 6.0. It is increased in the presence of acetate ions but was not affected by citrate and phosphate ions. PMID:22707821

  5. How Might New Neurons Buffer Against Stress?

    MedlinePLUS

    How Might New Neurons Buffer Against Stress? Recent News Boys Prescribed Antipsychotics More Often July 1, 2015 Study May Help VA ... Treatments (71 items) Clues Emerging from Studies in New Porter Neuroscience Center July 18, 2014 • Science Update ...

  6. Competitive Parallel Disk Prefetching and Buffer Management

    E-print Network

    Barve, Rakesh; Kallahalla, Mahesh; Varman, Peter J.; Vitter, Jeffrey Scott

    2000-01-01

    We provide a competitive analysis framework for online prefetching and buffer management algorithms in parallel I/O systems, using a read-once model of block references. This has widespread applicability to key I/O-bound applications...

  7. Synthesis of ethyl acetate employing celite-immobilized lipase of Bacillus cereus MTCC 8372.

    PubMed

    Verma, M L; Azmi, W; Kanwar, S S

    2009-09-01

    A wide range of fatty acid esters can be synthesized by esterification and transesterification reactions catalyzed by lipases in non-aqueous systems. In the present study, immobilization of a purified alkaline extra-cellular lipase of Bacillus cereus MTCC 8372 by adsorption on diatomaceous earth (celite) for synthesis of ethyl acetate via transesterification route was investigated. B. cereus lipase was deposited on celite (77% protein binding efficiency) by direct binding from aqueous solution. Immobilized lipase was used to synthesis of ethyl acetate from vinyl acetate and ethanol in n -nonane. Various reaction conditions, such as biocatalyst concentration, substrates concentration, choices of solvents ( n -alkanes), incubation time, temperature, molecular sieves (3A x 1.5 mm), and water activity(a w ), were optimized. The immobilized lipase (25 mg/ml) was used to perform transesterification in n -alkane(s) that resulted in approximately 73.7 mM of ethyl acetate at 55 degrees C in n -nonane under shaking (160 rpm) after 15 h, when vinyl acetate and ethanol were used in a equimolar ratio (100 mM each). Addition of molecular sieves (3A x 1.5 mm) as well as effect of water activity of saturated salt solutions (KI, KCl and KNO 3 ) to the transesterification efficiency has inhibitory effect. Batch operational stability tests indicated that immobilized lipase had retained 50% of its original catalytic activity after four consecutive batches of 15 h each. PMID:19789138

  8. Hormetic effect of ionic liquid 1-ethyl-3-methylimidazolium acetate on bacteria.

    PubMed

    Nancharaiah, Y V; Francis, A J

    2015-06-01

    The biological effect of ionic liquids (ILs) is one of the highly debated topics as they are being contemplated for various industrial applications. 1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]) showed remarkable hormesis on anaerobic Clostridium sp. and aerobic Pseudomonas putida. Bacterial growth was stimulated at up to 2.5 g L(-1) and inhibited at >2.5 g L(-1) of [EMIM][Ac]. The growth of Clostridium sp. and P. putida were higher by 0.4 and 4-fold respectively, in the presence of 0.5 g L(-1) [EMIM][Ac]. Assessment of the effect of [EMIM][Ac] under different growth conditions showed that the hormesis of [EMIM][Ac] was mediated via regulation of medium pH. Hormetic effect of [EMIM][Ac] was evident only in medium with poor buffering capacity and in the presence of a fermentable substrate as the carbon source. The hormetic effect of [EMIM][Ac] on bacterial growth is most likely associated with the buffering capacity of acetate anion. These observations have implications in ILs toxicity studies and ecological risk assessment. PMID:25703901

  9. Hormetic effect of ionic liquid 1-ethyl-3-methylimidazolium acetate on bacteria

    DOE PAGESBeta

    Nancharaiah, Y. V.; Francis, A. J.

    2015-06-01

    The biological effect of ionic liquids (ILs) is one of the highly debated topics as they are being contemplated for various industrial applications. 1-ethyl-2-methylimidazolium acetate ([EMIM][Ac]) showed remarkable hormesis on anaerobic Clostridium sp. and aerobic Psueudomonas putida. Bacterial growth was stimulated at up to 2.5 g L-1 and inhibited at > 2.5 g L-1 of ([EMIM][Ac]). The growth of Clostridium sp. and P. putida were higher by 0.4 and 4-fold respectively, in the presense of 0.5 g L-1 of ([EMIM][Ac]). Assessment of the effect of [EMIM][Ac] under different growth conditions showed that the hormesis of [EMIM][Ac] was mediated via regulationmore »of medium pH. Hormetic effect of [EMIM][Ac] was evident only in medium with poor buffering capacity and in the presence of a fermentable substrate as the carbon source. The hormetic effect of [EMIM][Ac] on bacterial growth is most likely associated with the buffering capacity of acetate anion. These observations have implications in ILs toxicity studies and ecological risk assessment.« less

  10. Buffer Standards for the Physiological pH of the Zwitterionic Compound, DIPSO from 5 to 55°C

    PubMed Central

    Roy, Lakshmi N.; Roy, Rabindra N.; LeNoue, Sean R.; Denton, Cole E.; Fuge, Michael S.; Dunseth, Craig D.; Roy, Chandra N.; Hayden, Shawn M.; Wollen, Joshua T.; Sreepada, Kripa

    2009-01-01

    The values of the second dissociation constant, pK2, and related thermodynamic quantities of 3-[N,N-bis (2-hydroxyethyl)amino]-2-hydroxypropanesulfonic acid (DIPSO) have already been reported over the temperature range 5 to 55°C including 37°C. This paper reports the pH values of four NaCl-free buffer solutions and four buffer composition containing NaCl salt at I = 0.16 mol·kg?1. Conventional paH values are reported for all eight buffer solutions. The operational pH values have been calculated for four buffer solutions recommended as pH standards, at 25 and 37°C after correcting the liquid junction potentials with the flowing junction cell. PMID:20160870

  11. ABS: Adaptive Buffer Sizing for Heterogeneous Networks

    Microsoft Academic Search

    Yueping Zhang; Dmitri Loguinov

    2008-01-01

    Abstract—Most existing criteria [3], [5], [9] for sizing router buffers rely on explicit formulation,of the relationship between buffer size and characteristics of Internet traffic. However, this is a non-trivial, if not impossible, task given that the number of flows, their individual RTTs, and congestion control methods, as well as flow responsiveness, are unknown. In this paper, we undertake,a completely,different approach,that

  12. Electron conducting buffer layers in organic photovoltaics

    Microsoft Academic Search

    Brian E. Lassiter; Guodan Wei; Xin Xiao; Siyi Wang; Mark E. Thompson; Stephen R. Forrest

    2011-01-01

    It is common to incorporate a cathode-side buffer layer in organic photovoltaic devices (OPVs) to mitigate damage from the evaporation of metal onto the underlying acceptor layer (e.g. C60), which can lead to exciton quenching and\\/or a barrier to charge extraction. Additionally, these materials can act as both an optical spacer and an exciton blocking layer. One class of buffer

  13. Determination of Unknown Concentrations of Sodium Acetate Using the Method of Standard Addition and Proton NMR: An Experiment for the Undergraduate Analytical Chemistry Laboratory

    ERIC Educational Resources Information Center

    Rajabzadeh, Massy

    2012-01-01

    In this experiment, students learn how to find the unknown concentration of sodium acetate using both the graphical treatment of standard addition and the standard addition equation. In the graphical treatment of standard addition, the peak area of the methyl peak in each of the sodium acetate standard solutions is found by integration using…

  14. Chemistry of enol ethers. LXXIX. Reaction of glutaconaldehyde acetals and their derivatives with heterocyclic compounds. The synthesis of tricarbocyanine dyes

    SciTech Connect

    Makin, S.M.; Kruglikova, R.I.; Shavrygina, O.A.; Kolobova, T.P.; Popova, T.P.; Tagirov, T.K.

    1988-03-10

    The acetal forms of glutaconaldehyde (2,6-dialkoxypyrans, 1,1,5,5-tetraalkoxy-2-pentenes, 5,5-dialkoxy-2-pentenals, and 1,3,5,5-tetraalkoxy-1-pentenes) are capable of reacting with quaternary salts of heterocyclic bases containing an active methyl group in acetic anhydride solution and in the presence of triethylamine with the formation of tricarbocyanine dyes. Syntheses are reported of unsubstituted thio-, indo-, and quinotricarbocyanines and derivatives with various substituents in the polymethine chain. The reaction proceeds readily upon heating glutaconaldehyde derivatives with quaternary salts in acetic anhydride in the presence of triethylamine.

  15. Distinguishing between Luminal and Localized Proton Buffering Pools in Thylakoid Membranes1

    PubMed Central

    Ewy, Robert G.; Dilley, Richard A.

    2000-01-01

    The dual gradient energy coupling hypothesis posits that chloroplast thylakoid membranes are energized for ATP formation by either a delocalized or a localized proton gradient geometry. Localized energy coupling is characterized by sequestered domains with a buffering capacity of approximately 150 nmol H+ mg?1 chlorophyll (Chl). A total of 30 to 40 nmol mg?1 Chl of the total sequestered domain buffering capacity is contributed by lysines with anomolously low pKas, which can be covalently derivatized with acetic anhydride. We report that in thylakoid membranes treated with acetic anhydride, luminal acidification by a photosystem I (duraquinol [DQH2] to methyl viologen [MV]) proton pumping partial reaction was nearly completely inhibited, as measured by three separate assays, yet surprisingly, H+ accumulation still occurred to the significant level of more than 100 nmol H+ mg Chl?1, presumably into the sequestered domains. The treatment did not increase the observed rate constant of dark H+ efflux, nor was electron transport significantly inhibited. These data provide support for the existence of a sequestered proton translocating pathway linking the redox reaction H+ ion sources with the CF0 H+ channel. The sequestered, low-pKa Lys groups appear to have a role in the H+ diffusion process and chemically modifying them blocks the putative H+ relay system. PMID:10677451

  16. Heuristic Models for Material Discharge from Landscapes with Riparian Buffers

    Microsoft Academic Search

    Donald E. Weller; Thomas E. Jordan; David L. Correll

    1998-01-01

    For landscapes with riparian buffers, we develop and analyze models pre- dicting landscape discharge based on material release by an uphill source area, the spatial distribution of riparian buffer along a stream, and retention within the buffer. We model the buffer as a grid of cells, and each cell transmits a fixed fraction of the materials it receives. We consider

  17. A REVIEW OF THE SCIENTIFIC LITERATURE ON RIPARIAN BUFFER

    E-print Network

    Rosemond, Amy Daum

    1 A REVIEW OF THE SCIENTIFIC LITERATURE ON RIPARIAN BUFFER WIDTH, EXTENT AND VEGETATION Seth Wenger-defensible basis for determining riparian buffer width, extent and vegetation. This docu- ment presents the results erosion. Studies have yielded a range of recom- mendations for buffer widths; buffers as narrow as 4.6 m

  18. An Efficient Buffer Memory System for Subarray Access

    Microsoft Academic Search

    Jong Won Park

    2001-01-01

    Many current graphical display systems utilize a buffer memory system to contain a two-dimensional image array to be modified and displayed. In order to speed up the update of the buffer memory system, it is required that the buffer memory system accesses many image points within an image subarray in parallel. This paper proposes an efficient buffer memory system for

  19. Counterexample-Guided SMT-Driven Optimal Buffer Sizing

    E-print Network

    Seshia, Sanjit A.

    Counterexample-Guided SMT-Driven Optimal Buffer Sizing Bryan A. Brady1 Daniel Holcomb1 Sanjit A of network-on-chip (NoC) designs depends crucially on the size of buffers in NoC components. While buffers latency. In this paper, we present a new approach for minimizing the cumulative buffer size in on- chip

  20. Treatment of Pedophilia with Leuprolide Acetate

    Microsoft Academic Search

    Nancy Raymond; Bean Robinson; Chris Kraft; Barry Rittberg; Eli Coleman

    2002-01-01

    To date, the literature on the treatment of individuals who have committed sexual offenses has focused primarily on psychotherapeutic interventions and the use of antiandrogens. Recently case reports and small series supporting the efficacy of other psychiatric medication, such as serotonin reuptake inhibitors, have been published. Only a few publications have looked at the efficacy of leuprolide acetate, an LH-RH

  1. Heat Bonding of Irradiated Ethylene Vinyl Acetate

    NASA Technical Reports Server (NTRS)

    Slack, D. H.

    1986-01-01

    Reliable method now available for joining parts of this difficult-tobond material. Heating fixture encircles ethylene vinyl acetate multiplesocket part, providing heat to it and to tubes inserted in it. Fixtures specially designed to match parts to be bonded. Tube-and-socket bonds made with this technique subjected to tensile tests. Bond strengths of 50 percent that of base material obtained consistently.

  2. Fragrance material review on ?-methylbenzyl acetate.

    PubMed

    McGinty, D; Letizia, C S; Api, A M

    2012-09-01

    A toxicologic and dermatologic review of ?-methylbenzyl acetate when used as a fragrance ingredient is presented. ?-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for ?-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, and repeated dose data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22406576

  3. Fragrance material review on benzyl acetate.

    PubMed

    McGinty, D; Vitale, D; Letizia, C S; Api, A M

    2012-09-01

    A toxicologic and dermatologic review of benzyl acetate when used as a fragrance ingredient is presented. Benzyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for benzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, phototoxicity, toxicokinetics, repeated dose, reproductive toxicity, genotoxicity, or carcinogenicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Refer Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22387848

  4. Process for the preparation of vinyl acetate

    DOEpatents

    Tustin, Gerald Charles (Kingsport, TN); Zoeller, Joseph Robert (Kingsport, TN); Depew, Leslie Sharon (Kingsport, TN)

    1998-01-01

    This invention pertains to the preparation of vinyl acetate by contacting within a contact zone a mixture of ketene and acetaldehyde with an acid catalyst at about one bar pressure and between about 85.degree. and 200.degree. C. and removing the reaction products from the contact zone.

  5. boxcar, width, [buffer, /decimate] Boxcar smoothing clip, datamin, datamax, [buffer, /blank] Truncate spectrum to a min and max data value

    E-print Network

    Groppi, Christopher

    Other boxcar, width, [buffer, /decimate] Boxcar smoothing clip, datamin, datamax, [buffer, /blank the data end-to-end mediansub, width, [buffer] Subtract the median filtered values of the given width from] Truncate spectrum to a min and max data value decimate, [nchan, startat, buffer, ok] Decimate the spectrum

  6. Potential Efficiency of Riparian Vegetated Buffer Strips in Intercepting Soluble Compounds in the Presence of Subsurface Preferential Flows.

    PubMed

    Allaire, Suzanne Edith; Sylvain, Claudia; Lange, Sébastien F; Thériault, George; Lafrance, Pierre

    2015-01-01

    Buffer strips have been widely recognized as to promote infiltration, deposition and sorption of contaminants for protecting surface water against agricultural contamination. However, such strips do not intercept all contaminants, particularly soluble ones. Although preferential flow (PF) has been suggested as one factor among several decreasing the efficiency of buffer strips, the mechanisms involved are not well understood. This project examines buffer strip efficiency at intercepting solutes when subsurface PF occurs. Two soluble sorbed tracers, FD&C Blue #1 and rhodamine WT, were applied on an agricultural sandy loam soil to evaluate the ability of a naturally vegetated buffer strip to intercept soluble contaminants. Rhodamine was applied about 15 m from the creek, while the Blue was applied 15 m to 165 m from the creek. Tracer concentration was measured over a two-year period in both the creek and the buffer strip through soil and water samples. Although the tracers traveled via different pathways, they both quickly moved toward the creek, passing beneath the buffer strip through the soil matrix. Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used. The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed. PMID:26147093

  7. Potential Efficiency of Riparian Vegetated Buffer Strips in Intercepting Soluble Compounds in the Presence of Subsurface Preferential Flows

    PubMed Central

    Allaire, Suzanne Edith; Sylvain, Claudia; Lange, Sébastien F.; Thériault, George; Lafrance, Pierre

    2015-01-01

    Buffer strips have been widely recognized as to promote infiltration, deposition and sorption of contaminants for protecting surface water against agricultural contamination. However, such strips do not intercept all contaminants, particularly soluble ones. Although preferential flow (PF) has been suggested as one factor among several decreasing the efficiency of buffer strips, the mechanisms involved are not well understood. This project examines buffer strip efficiency at intercepting solutes when subsurface PF occurs. Two soluble sorbed tracers, FD&C Blue #1 and rhodamine WT, were applied on an agricultural sandy loam soil to evaluate the ability of a naturally vegetated buffer strip to intercept soluble contaminants. Rhodamine was applied about 15 m from the creek, while the Blue was applied 15 m to 165 m from the creek. Tracer concentration was measured over a two-year period in both the creek and the buffer strip through soil and water samples. Although the tracers traveled via different pathways, they both quickly moved toward the creek, passing beneath the buffer strip through the soil matrix. Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used. The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed. PMID:26147093

  8. Calcium Gluconate in Phosphate Buffered Saline Increases Gene Delivery with Adenovirus Type 5

    E-print Network

    Hemminki, Akseli

    Calcium Gluconate in Phosphate Buffered Saline Increases Gene Delivery with Adenovirus Type 5 Marko the calcium and phosphate present in the serum mix to precipitate, and this was responsible for enhanced gene calcium and phosphate are present in many solutions. To translate this into an approach potentially

  9. A universal building block for the approximate analysis of a shared buffer ATM switch architecture

    Microsoft Academic Search

    Demetres D. Kouvatsos; Spiros G. Denazis

    1994-01-01

    A universal analytic approximation is proposed for the performance analysis of a general queueing model of a shared buffer ATM switch architecture with bursty arrivals. The forms of the joint, aggregate and marginal state probabilities are characterised via entropy maximisation. As an application, a continuous-time maximum entropy (ME) solution is implemented at equilibrium by assuming that the arrival process to

  10. Author's personal copy Evaluation of stainless steel cathodes and a bicarbonate buffer

    E-print Network

    ), although carbonate buffers have been shown to work in other bioelectrochemical systems with a platinum (Pt, where bacteria oxidize the substrate, donate the electrons to the anode, and produce protons which go into solution. The electrons travel through the circuit and combine with protons on the cathode, usually

  11. Phenyl Acetate Preparation from Phenol and Acetic Acid: Reassessment of a Common Textbook Misconception.

    ERIC Educational Resources Information Center

    Hocking, M. B.

    1980-01-01

    Reassesses a common textbook misconception that "...phenols cannot be esterified directly." Results of experiments are discussed and data tables provided of an effective method for the direct preparation of phenyl acetate. (CS)

  12. Acetic Acid Detection Threshold in Synthetic Wine Samples of a Portable Electronic Nose

    PubMed Central

    Macías, Miguel Macías; Manso, Antonio García; Orellana, Carlos Javier García; Velasco, Horacio Manuel González; Caballero, Ramón Gallardo; Chamizo, Juan Carlos Peguero

    2013-01-01

    Wine quality is related to its intrinsic visual, taste, or aroma characteristics and is reflected in the price paid for that wine. One of the most important wine faults is the excessive concentration of acetic acid which can cause a wine to take on vinegar aromas and reduce its varietal character. Thereby it is very important for the wine industry to have methods, like electronic noses, for real-time monitoring the excessive concentration of acetic acid in wines. However, aroma characterization of alcoholic beverages with sensor array electronic noses is a difficult challenge due to the masking effect of ethanol. In this work, in order to detect the presence of acetic acid in synthetic wine samples (aqueous ethanol solution at 10% v/v) we use a detection unit which consists of a commercial electronic nose and a HSS32 auto sampler, in combination with a neural network classifier (MLP). To find the characteristic vector representative of the sample that we want to classify, first we select the sensors, and the section of the sensors response curves, where the probability of detecting the presence of acetic acid will be higher, and then we apply Principal Component Analysis (PCA) such that each sensor response curve is represented by the coefficients of its first principal components. Results show that the PEN3 electronic nose is able to detect and discriminate wine samples doped with acetic acid in concentrations equal or greater than 2 g/L. PMID:23262483

  13. Simultaneous Capillary Gas Chromatographic Determination of Cyproterone Acetate and 15?-Hydroxycyproterone Acetate in Urine

    Microsoft Academic Search

    Jasmina Novakovic; Eva Tvrzická

    1993-01-01

    The simultaneous capillary GC determination of underivatized antiandrogen cyproterone acetate (CPA) and its active metabolite 15?-hydroxycyproterone acetate (OH-CPA) in spiked urine was performed on a flexible VCOT quartz capillary column, coated with a non-polar CP-Sil 5 CB liquid phase. A split\\/splitless injector and a flame-ionization detector were used. Equilin was used as an internal standard, and resolution of all the

  14. 21 CFR 520.1341 - Megestrol acetate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Megestrol acetate tablets. 520.1341 Section 520.1341 Food and...ANIMAL DRUGS § 520.1341 Megestrol acetate tablets. (a) Specifications. Each tablet contains 5 or 20 milligrams of megestrol...

  15. 21 CFR 520.1341 - Megestrol acetate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Megestrol acetate tablets. 520.1341 Section 520.1341 Food and...ANIMAL DRUGS § 520.1341 Megestrol acetate tablets. (a) Specifications. Each tablet contains 5 or 20 milligrams of megestrol...

  16. Studies on an acetate-fermenting strain of Methanosarcina.

    PubMed

    Mah, R A; Smith, M R; Baresi, L

    1978-06-01

    An acetate-fermenting strain of Methanosarcina was isolated from an acetate enrichment culture inoculated with anaerobic sludge from a waste treatment digestor. In pure culture, this organism fermented acetate in the absence of added hydrogen at rates comparable in magnitude to those found in digestor systems. This rate was significantly higher than previously obtained for pure cultures of this genus. Mineral components of yeast extract were highly stimulatory for cultures growing on methanol. Comparable stimulation was not observed for cultures growing on acetate. Labeling studies indicated that acetate was converted to methane and CO2 as predicted by previous studies on mixed cultures. Total oxidation or reduction of acetate was not the mechanism of conversion of acetate to methane by the pure culture. The ability of this strain to form colonies or to produce methane from acetate was apparently influenced by the choice of substrate and conditions used for growing the inoculum. PMID:677880

  17. Myelin basic protein purified on an ion-exchange continuous polymer bed in the presence of ethylene glycol and salt possesses activity against p -nitrophenyl acetate

    Microsoft Academic Search

    Jan Sedzik; Jamil Mohammad; Stellan Hjertén

    1995-01-01

    In this paper we describe a fast and mild method based on the use of a unique cation exchanger and buffers containing ethylene glycol and salt for the purification of the myelin basic protein (MBP; MW 18.5 kDa). MBP thus purified hydrolyses catalytically p-nitrophenyl acetate. This esterase activity facilitates not only the purification of MBP but also indicates that probably

  18. Expression of Acetate Permease-like (apl) Genes in Subsurface Communities of Geobacter Species Under Fluctuating Acetate Concentrations

    SciTech Connect

    Elifantz, H.; N'Guessan, A. L.; Mouser, Paula; Williams, Kenneth H.; Wilkins, Michael J.; Risso, Carla; Holmes, Dawn; Long, Philip E.; Lovley, Derek R.

    2010-09-01

    The addition of acetate to uranium-contaminated aquifers in order to stimulate the growth and activity of Geobacter species that reduce uranium is a promising in situ bioremediation option. Optimizing this bioremediation strategy requires that suf?cient acetate be added to promote Geobacter species growth. We hypothesized that under acetate-limiting conditions, subsurface Geobacter species would increase the expression of either putative acetate symporters genes (aplI and aplII). Acetate was added to a uranium-contaminated aquifer (Ri?e, CO) in two continuous amendments separated by 5 days of groundwater ?ush to create changing acetate concentrations. While the expression of aplI in monitoring well D04 (high acetate) weakly correlated with the acetate concentration over time, the transcript levels for this gene were relatively constant in well D08 (low acetate). At the lowest acetate concentrations during the groundwater ?ush, the transcript levels of aplII were the highest. The expression of aplII decreased 2–10-fold upon acetate reintroduction. However, the overall instability of acetate concentrations throughout the experiment could not support a robust conclusion regarding the role of apl genes in response to acetate limitation under ?eld conditions, in contrast to previous chemostat studies, suggesting that the function of a microbial community cannot be inferred based on lab experiments alone.

  19. Suitability of the pH buffers 3-[N-N-bis(hydroxyethyl)amino]-2-hydroxypropanesulfonic acid and N-2-hydroxyethylpiperazine-N?-2-ethanesulfonic acid for in vitro copper toxicity studies

    Microsoft Academic Search

    O. M. Lage; M. T. S. D. Vasconcelos; H. M. V. M. Soares; J. M. Osswald; F. Sansonetty; A. M. Parente; R. Salema

    1996-01-01

    The influence of the zwitterionic (ampholytic) pH buffers, 3-[N-N-bis(hydroxyethyl)amino]-2-hydroxypropanesulfonic acid (DIPSO, 10 mM) and N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES, 25 mM), on the toxicity of copper(II) to the marine dinoflagellate, Amphidinium carterae, was investigated. For this purpose, DIPSO or HEPES buffered complete ESAW (enrichment solution artificial seawater) growth media as well as simplified (enrichment solution deficient) buffered media were assayed in the

  20. On the buffer capacity of CO 2 -charged seawater used for carbonation and subsequent mineral sequestration

    Microsoft Academic Search

    Domenik Wolff-Boenisch

    2011-01-01

    Successful mineral trapping of carbon dioxide faces the challenge of effectively titrating a CO2-charged acidic injection solution to pH conditions favorable to carbonate precipitation -using the rock as primary alkalinity source. To illustrate the magnitude of this task, buffer capacities of seawater solutions equilibrated with different partial pressure of CO2 are presented, under open and closed conditions. A number of

  1. Post-harvest Riparian Buffer Response: Implications for Wood Recruitment Modeling and Buffer Design

    NASA Astrophysics Data System (ADS)

    Liquori, Michael K.

    2006-02-01

    Despite the importance of riparian buffers in providing aquatic functions to forested streams, few studies have sought to capture key differences in ecological and geomorphic processes between buffered sites and forested conditions. This study examines post-harvest buffer conditions from 20 randomly selected harvest sites within a managed tree farm in the Cascade Mountains of western Washington. Post-harvest wind derived treefall rates in buffers up to three years post-harvest averaged 268 trees/km/year, 26 times greater than competition-induced mortality rate estimates. Treefall rates and stem breakage were strongly tied to tree species and relatively unaffected by stream direction. Observed treefall direction is strongly biased toward the channel, irrespective of channel or buffer orientation. Fall direction bias can deliver significantly more wood recruitment relative to randomly directed treefall, suggesting that models that utilize the random fall assumption will significantly underpredict recruitment. A simple estimate of post-harvest wood recruitment from buffers can be obtained from species specific treefall and breakage rates, combined with bias corrected recruitment probability as a function of source distance from the channel. Post-harvest wind effects may reduce the standing density of trees enough to significantly reduce or eliminate competition mortality and thus indirectly alter bank erosion rates, resulting in substantially different wood recruitment dynamics from buffers as compared to unmanaged forests.

  2. Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins

    ERIC Educational Resources Information Center

    Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

    2011-01-01

    A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

  3. Original article Ethanol and acetic-acid tolerance

    E-print Network

    Paris-Sud XI, Université de

    Original article Ethanol and acetic-acid tolerance in Indian geographical populations of Drosophila clines of ethanol toler- ance (1.5-4.2%) and acetic-acid tolerance (2.9-4.9%) were observed in adult individuals of 4 geographical populations of Drosophila immigrans. Thus, both ethanol and acetic

  4. Solutions : WtPercentToMolarity (4 Variations)

    NSDL National Science Digital Library

    A common concentration unit used commercially is percent weight per volume (%W/V) which is the number of grams of solute in 100 mL of solution. A bottle of vinegar contains 5 %W/V acetic acid (CH 3 COOH). What is the molar concentration of acetic acid in the vinegar?

  5. Stability of poly(D,L-lactide-co-glycolide) and leuprolide acetate in in-situ forming drug delivery systems.

    PubMed

    Dong, W Y; Körber, M; López Esguerra, V; Bodmeier, R

    2006-10-10

    In-situ forming drug delivery systems are prepared by dissolving a drug and a biodegradable polymer (poly(D,L-lactide-co-glycolide), PLGA) in a biocompatible organic solvent (In-situ implant, ISI) or further emulsified into an external phase (oil or aqueous solution), resulting in oil-in-oil or oil-in-water emulsions (In-situ forming microparticles, ISM). The chemical stability of PLGA and the drug is a major concern. In this study, the stability of PLGA and leuprolide acetate in the in-situ forming systems and lyophilized sponges was investigated. The degradation of PLGA increased with increasing storage temperature and water content in the biocompatible solvents. A faster degradation occurred in polar protic solvents (2-pyrrolidone, PEG 400, triethyl citrate) than in polar aprotic solvents (N-methyl-2-pyrrolidone, DMSO, triacetin, ethyl acetate). The presence of leuprolide acetate significantly accelerated PLGA degradation, especially in solution state. PLGA was stable in oily suspensions at 4 degrees C and degraded only slightly faster than solid powder at 25 degrees C. No interaction between the oils and the PLGA was observed as indicated by an unchanged T(g) of approx. 47 degrees C. PLGA underwent a slight degradation at 4 degrees C after 150 days in water and saturated sodium chloride solution. The degradation was slower in saturated sodium chloride solution than in water at 25 degrees C. Residual acetic acid in lyophilized sponges facilitated the PLGA degradation in contrast to dioxane. Leuprolide acetate did not affect the PLGA stability negatively. However, lidocaine significantly enhanced the polymer degradation in the sponges. Finally, leuprolide acetate was chemically stable in the sponges, the oils and the polymer solutions in suspension state, but unstable (aggregation) when dissolved in the polymer solutions and stored at 25 degrees C and 40 degrees C. PMID:16963145

  6. Assessment Guidelines for Managing Cellulose Acetate Collections

    NSDL National Science Digital Library

    2001-01-01

    Photographic negatives, motion picture film, microfilm, and sound recordings produced from the 1930s into the 1950s often used cellulose acetate as the transparent plastic carrier. As anyone who has ever come in contact with it well knows, its strong vinegar-like scent is hard to miss. Unfortunately, over time, the material is prone to deterioration, which eventually renders it unusable. In an effort to help guide libraries in Australia with this problem, the National Library of Australia has created this document. It provides assistance in identification of cellulose acetate (vs. other similar materials) and establishes criteria to assess condition, cultural importance, and use within the library or storage context. The document guides readers through the first step in a strategy for preserving these collections.

  7. Ulipristal acetate: the newest emergency contraceptive.

    PubMed

    Wilton, Jeanne M

    2012-01-01

    More than 50 percent of pregnancies in the United States are unplanned. Emergency contraception has been shown to possibly reduce the risk of pregnancy by as much as 75 percent. Ulipristal acetate is a selective progesterone receptor modulator that was approved by the U.S. Food and Drug Administration (FDA) for emergency contraceptive use in August 2010. This article reviews information on its mechanism of action, efficacy, safety and implications for women's health nurses. PMID:22900810

  8. Mechanical and optical characterization of cellulose acetate

    Microsoft Academic Search

    H. Ishikawa; S. Tadano

    1988-01-01

    To obtain the basic relations for photo-viscoelastoplastic stress analysis using cellulose acetate, the effect of strain rate\\u000a as well as room temperature on mechanical and optical properties was precisely investigated by the uniaxial tension test.\\u000a As a result, the nonlinear stress-strain, the non-linear-stress-fringe order and the nonlinear-fringe-order strain relations\\u000a were uniquely reoresented in their nondimensional forms regardless of strain rate

  9. Calcium magnesium acetate production and cost reduction

    SciTech Connect

    Leuschner, A.P.

    1988-02-01

    The New York State Energy Research and Development Authority (Energy Authority), Consolidated Edison Company of New York, Inc. (ConEd), the New York State Department of Transportation (NYSDOT), the New York State Thruway Authority (NYSTA), Chevron Chemical Company, the National Corn Growers Association (NCGA), and the Massachusetts Department of Public Works (MDPW) sponsored a research program to develop technology capable of producing Calcium Magnesium Acetate (CMA), an alternative road deicer, at a quality and cost which will allow its increased use. The objectives of this program were to determine the feasibility of: (1) producing CMA from regionally available waste and low grade organic feedstocks via biochemical engineering technologies; (2) operating the fermentation at concentrated product levels to reduce energy requirements and minimize drying process costs; (3) using this production approach to produce an environmentally acceptable CMA product; and (4) using and adapting an existing facility for a CMA commercial demonstration plant. The experimental program included:(1) selection of microorganisms for their ability to grow in the absence of sodium chloride and to tolerate high concentrations of calcium, magnesium, and acetate ions; (2) analysis of waste feedstocks for their potential conversion to acetate; (3) analysis of waste organic material for impurities in CMA that could carry over into the environment; (4) batch experiments to determine pH tolerance, growth in the absence of sodium chloride (NaCl), tolerance to magnesium, calcium and acetate ions, effect of substrate concentration, acid distribution, and acid production; and (5) semi-continuous laboratory scale anaerobic digestion experiments to determine loading rates, conversion efficiencies, and other design data. 67 refs., 33 figs., 66 tabs.

  10. Nonlinear Dielectric Relaxation Spectra of Polyvinyl Acetate

    Microsoft Academic Search

    Takeo Furukawa; Kiyokazu Matsumoto

    1992-01-01

    The frequency spectra of the linear and third nonlinear permittivities, \\\\varepsilon1* and \\\\varepsilon3*, have been measured for polyvinyl acetate (PVAc) at temperatures above Tg. The Debye relaxation of \\\\varepsilon1* associated with the micro-Brownian motion of noncrystalline segments is found to be accompanied by the complex frequency dependence of \\\\varepsilon3* due to combined contributions from the intrinsic nonlinear dielectricity and the

  11. Understanding the Science Behind Riparian Forest Buffers

    E-print Network

    Liskiewicz, Maciej

    on the stream's con- dition and on the adjoining watershed will help deter- mine how wide the buffer should be). Watershed To understand the forces affecting a par- ticular stream segment, it is important to look at the entire watershed (Figure 2). A stream is influenced by many factors, including the area's geology

  12. A Discovery Chemistry Experiment on Buffers

    ERIC Educational Resources Information Center

    Kulevich, Suzanne E.; Herrick, Richard S.; Mills, Kenneth V.

    2014-01-01

    The Holy Cross Chemistry Department has designed and implemented an experiment on buffers as part of our Discovery Chemistry curriculum. The pedagogical philosophy of Discovery Chemistry is to make the laboratory the focal point of learning for students in their first two years of undergraduate instruction. We first pose questions in prelaboratory…

  13. Buffer layers on biaxially textured metal substrates

    DOEpatents

    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

    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.

  14. Research Councils: Buffers under Cross Pressures.

    ERIC Educational Resources Information Center

    Fenger, Pim

    1992-01-01

    The role of national research councils as buffers between the state and the scientific community is discussed from three perspectives--research councils as part of a stratified, dispersed decision-making structure; a para-governmental organization; and promoting transnationalization of scientific and educational exchange. Pressures and threats on…

  15. A Review of Buffer Strip Design Algorithms

    Microsoft Academic Search

    Leon J. Bren

    Strips of trees left along streams (buffers) are a fundamental protection against stream pollution in forest harvesting. However this raises the question of just how wide such strips should be, and this has important effects on the economic productivity of land-based ventures. Various algorithms for computation of the appropriate width are reviewed in the light of the author's research. It

  16. DETERGENTS & BUFFERS 10394 Pacific Center Court

    E-print Network

    Lebendiker, Mario

    DETERGENTS & BUFFERS 10394 Pacific Center Court San Diego, CA 92121 (858) 450-9600 Customer Service: (800) 854-3417 Technical Service: (800) 628-8470 Fax: (800) 776-0999 CALBIOCHEM IONIC DETERGENTS BATC Tauroursodeoxycholic Acid, Sodium Salt 580549 521.7 -- -- -- 1 g 5 g TOPPS 615000 350.5 4.5 -- -- 5 g Detergent Cat. No

  17. Buffering children from marital conflict and dissolution.

    PubMed

    Katz, L F; Gottman, J M

    1997-06-01

    Examined several protective mechanisms that may reduce deleterious correlates of marital conflict and marital dissolution in young children. One set of potential buffers focused on parent-child interaction: parental warmth, parental scaffolding/praise, and inhibition of parental rejection. As a second set of potential buffers, each parent was interviewed about their "meta-emotion philosophy"--that is, their feelings about their own emotions, and their attitudes and responses to their children's anger and sadness. The third set of potential buffers concerned intraindividual characteristics of the child, including the child's intelligence and regulatory physiology (basal vagal tone and vagal suppression). Fifty-six families with a preschool child were studied at two time points: when the children were 5 years old (Time 1) and again when the children were 8 years old (Time 2). At Time 1, naturalistic observations of marital and parent-child interaction were conducted and assessment of child regulatory physiology was obtained through measures of basal vagal tone and suppression of vagal tone. Parents were also interviewed individually about their feelings about their own and their children's emotions, and children's intelligence was assessed. At Time 2, assessment of child outcomes were obtained, including observations of peer interaction, mother ratings of behavior problems and mother and teacher ratings of peer aggression, mother ratings of child physical illness, and measures of achievement. Results indicated that all Time 1 buffering factors protected children in face of marital conflict and dissolution. PMID:9169376

  18. Buffer overflow asymptotics for multiplexed regulated traffic

    Microsoft Academic Search

    Yu Ying; Fabrice Guillemin; Ravi Mazumdar; Catherine Rosenberg

    2008-01-01

    By characterizing the worst case profile, which maximizes the content of a buffer fed with leaky bucket regulated flows in packet telecommunication networks, we derive a tight upper bound in the many-sources regime for the tail distribution of the workload generated by these flows in a FIFO queue with constant service rate. Furthermore, we compare this workload distribution with an

  19. Silver acetate interactions with nicotine and non-nicotine smoke components.

    PubMed

    Rose, Jed E; Behm, Frédérique M; Murugesan, Thangaraju; McClernon, F Joseph

    2010-12-01

    Oral topical silver-containing formulations were marketed in the 1970s and 1980s as smoking deterrents, based on the finding that when using such formulations, an unpleasant taste occurs upon smoking. This approach has not been widely adopted, however, in part because of a lack of efficacy data. The advent of new pharmacologic treatments for smoking cessation renews the possibility that such a taste aversion approach may be a useful adjunct to smoking cessation treatment. This study explored the basic mechanistic question of whether topical oral silver acetate solution interacts with nicotine as opposed to non-nicotine smoke constituents. We recruited 20 smoking volunteers to rate nicotine-containing or denicotinized cigarettes, as well as the Nicotrol nicotine vapor inhaler and sham (air) puffs. In two sessions, subjects rated the sensory and hedonic qualities of puffs after rinsing their mouths with either silver acetate solution or deionized water (placebo). Silver acetate relative to placebo solution substantially reduced liking and satisfaction ratings for the usual brand and denicotinized cigarettes; in contrast, for the nicotine inhaler these ratings were unaffected by the silver-based treatment. These results support the conclusion that silver acetate not only renders the taste of cigarette smoke less appealing, but also that the compound appears to interact selectively with non-nicotine smoke constituents. Moreover, these data suggest silver acetate would be compatible with buccal nicotine delivery systems (e.g., nicotine lozenge or gum). Combined use of taste aversion with nicotine replacement therapy could provide the smoker with additional assistance to resist relapse. Further exploration is warranted of the use of silver-based preparations as a short-term adjunct to smoking cessation treatment. PMID:21186921

  20. Buffer-dependent fragmentation of a humanized full-length monoclonal antibody

    PubMed Central

    Salinas, Branden A; Sathish, Hasige A; Shah, Ambarish U; Carpenter, John F; Randolph, Theodore W

    2014-01-01

    During storage stability studies of a monoclonal antibody (mAb) it was determined that the primary route of degradation involved fragmentation into lower molecular weight species. The fragmentation was characterized with size-exclusion high performance liquid chromatography (SE-HPLC), SDS-PAGE and matrix assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. Fragmentation proceeded via hydrolysis, likely catalyzed by trace metal ions, of a peptide bond in the hinge region of the mAb’s heavy chain, which produced two prominent low molecular weight species during storage: a single, free Fab fragment and a Fab+Fc fragment. The fragmentation is observed in phosphate-buffered solutions at two ionic strengths but not in histidine-buffered solutions at identical ionic strengths. Chaotrope-induced and thermally-induced unfolding studies of the mAb indicated differences in the unfolding pathways between the two buffer solutions. This folding intermediate observed during chaotrope-induced unfolding was further characterized by intrinsic fluorescence quenching, which suggested that a small portion of the molecule is resistant to chaotrope-induced unfolding in histidine buffer systems. The thermally-induced unfolding indicates a reduction in cooperativity of the unfolding process in the presence of histidine relative to phosphate. A relationship between the histidine-induced effects on unfolding pathway and the relative resistance to fragmentation is suggested. PMID:20091831

  1. Experimental evidence of an acetate transporter protein and characterization of acetate activation in aceticlastic methanogenesis of Methanosarcina mazei.

    PubMed

    Welte, Cornelia; Kröninger, Lena; Deppenmeier, Uwe

    2014-10-01

    Aceticlastic methanogens metabolize acetate to methane and carbon dioxide. The central metabolism and the electron transport chains of these organisms have already been investigated. However, no particular attention has been paid to the mechanism by which acetate enters the archaeal cell. In our study we investigated Methanosarcina mazei acetate kinase (Ack) and the acetate uptake reaction. At a concentration of 2 mM acetate, the Ack activity in cell extract of M. mazei was not limiting for the methane formation rate. Instead, the methanogenesis rate was controlled by the substrate concentration and increased 10-fold at 10 mM acetate. Subsequently, we analyzed the involvement of the putative acetate permease MM_0903 using a corresponding deletion mutant. At 2 mM acetate, only 25% of the wild-type methane formation rate was measured in the mutant. This indicated that the supply of acetate to Ack was limiting the rate of methane formation. Moreover, the mutant revealed an increased acetate kinase activity compared with the wild type. These results show for the first time that an acetate transporter is involved in aceticlastic methanogenesis and may be an important factor in the acetate threshold concentration for methanogenesis of Methanosarcina spp. PMID:25088360

  2. Baroreflex buffering and susceptibility to vasoactive drugs

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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 and responses to vasoactive drugs in patients with idiopathic orthostatic intolerance, patients with essential hypertension, patients with monogenic hypertension and brachydactyly, patients with multiple system atrophy, and control subjects. We used phenylephrine sensitivity during ganglionic blockade as a measure of baroreflex buffering. Phenylephrine (25 microg) increased systolic blood pressure 6+/-1.6 mm Hg in control subjects, 6+/-1.1 mm Hg in orthostatic intolerance patients, 18+/-3.9 mm Hg in patients with essential hypertension, 31+/-3.4 mm Hg in patients with monogenic hypertension, and 25+/-3.4 mm Hg in patients with multiple system atrophy. Similar differences in sensitivities between groups were observed with nitroprusside. The sensitivity to vasoactive drugs was highly correlated with baroreflex buffering function and to a lesser degree with baroreflex control of heart rate. In control subjects, sensitivities to nitroprusside and phenylephrine infusions were correlated with baroreflex heart rate control and sympathetic nerve traffic. CONCLUSIONS: Our findings are consistent with an important effect of baroreflex blood pressure buffering on the sensitivity to vasoactive drugs. They suggest that even moderate changes in baroreflex function may have a substantial effect on the sensitivity to vasoactive medications.

  3. Simultaneous determination of norepinephrine, serotonin, and 5-hydroxyindole-3-acetic acid in microdialysis samples from rat brain by microbore column liquid chromatography with fluorescence detection following derivatization with benzylamine.

    PubMed

    Yoshitake, Takashi; Fujino, Kaoru; Kehr, Jan; Ishida, Junichi; Nohta, Hitoshi; Yamaguchi, Masatoshi

    2003-01-15

    A microbore column liquid chromatographic method for the simultaneous determination of norepinephrine (NE), serotonin (5-HT), and 5-hydroxyindole-3-acetic acid (5HIAA) in microdialysis samples from rat brain is described. The method is based on precolumn derivatization of NE, 5HT, and 5HIAA with benzylamine in the presence of potassium hexacyanoferrate(III) resulting in the corresponding highly fluorescent and stable benzoxazole derivatives. A 15-microl sample was mixed with 15 microl derivatization reagent solution containing 0.3M 3-cyclohexylaminopropanesulfonic acid buffer (pH 12.0), 0.5M benzylamine, 10mM potassium hexacyanoferrate(III), and methanol (1/1/1/12, v/v/v/v). The derivatization was carried out at 50 degrees C for 20 min. The benzylamine derivatives of NE, 5HT, and 5HIAA were separated on a reversed-phase column (100 x 1.0mm i.d., packed with C18 silica, 5 microm) within 30 min. The mobile phase consisted of 15 mM acetate buffer (pH 5.0) and acetonitrile (31%, v/v); the flow rate was 50 microl/min. The detection limits (signal-to-noise ratio of 3) for NE, 5HT, and 5HIAA in the injection volume of 20 microl were 90, 210, and 260 amol, respectively. Microdialysis samples were collected in 7.5-min intervals from the probes implanted in the hippocampus and prefrontal cortex of awake rats. The basal levels of NE, 5HT, and 5HIAA in the dialysates from the hippocampus were 4.2+/-0.5, 4.9+/-0.6, and 934.1 +/- 63.4 fmol/20 microl, and those from the prefrontal cortex were 6.0+/-1.2,5.51.3, and 669.1 +/- 96.0 fmol/20 microl (mean +/- SE, n=25), respectively. The NE and 5HT levels were altered by perfusion of high-potassium or low-calcium solution and following antidepressant drugs imipramine and desipramine. It is concluded that the new fluorescence derivatization method in combination with microbore column liquid chromatography allows the simultaneous determination of NE, 5HT, and 5HIAA in the microdialysis samples at higher sensitivity, providing easier maintenance in routine use than that achieved by high-performance liquid chromatographic methods with electrochemical detection. PMID:12531196

  4. Influence of different buffer gases on synthesis of few-layered graphene by arc discharge method

    NASA Astrophysics Data System (ADS)

    Shen, Baoshou; Ding, Jijun; Yan, Xingbin; Feng, Wangjun; Li, Jun; Xue, Qunji

    2012-03-01

    Few-layered graphene sheets were synthesized by direct current arc discharge using different buffer gases. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) and four-probe method. Moreover, the hydrophobility and the field emission properties of the sprayed-coating graphene films prepared by a direct solution process were studied. As a result, the generation of graphene sheets shows strong dependence on the composition of buffer gases and containing H2 buffer gases are necessary to prepare few-layered graphene sheets. The graphene sheets produced in H2-He buffer gases have better crystallinity and higher specific surface area compared with those produced in others containing H2 buffer gases. The as-obtained graphene sheets are mainly no more than 5 layers and their lateral dimensions are about 40-200 nm. The graphene sheets show excellent thermal stability and there is only less than 3 wt.% weight loss up to 800 °C in N2 atmosphere. The graphene sheets can be easily dispersed into ethanol and the as-obtained suspension can be stable for more than two months. The sprayed graphene films show good hydrophobility and a typical cold cathode field emission behavior.

  5. Adaptation and tolerance of bacteria against acetic acid.

    PubMed

    Tr?ek, Janja; Mira, Nuno Pereira; Jarboe, Laura R

    2015-08-01

    Acetic acid is a weak organic acid exerting a toxic effect to most microorganisms at concentrations as low as 0.5 wt%. This toxic effect results mostly from acetic acid dissociation inside microbial cells, causing a decrease of intracellular pH and metabolic disturbance by the anion, among other deleterious effects. These microbial inhibition mechanisms enable acetic acid to be used as a preservative, although its usefulness is limited by the emergence of highly tolerant spoilage strains. Several biotechnological processes are also inhibited by the accumulation of acetic acid in the growth medium including production of bioethanol from lignocellulosics, wine making, and microbe-based production of acetic acid itself. To design better preservation strategies based on acetic acid and to improve the robustness of industrial biotechnological processes limited by this acid's toxicity, it is essential to deepen the understanding of the underlying toxicity mechanisms. In this sense, adaptive responses that improve tolerance to acetic acid have been well studied in Escherichia coli and Saccharomyces cerevisiae. Strains highly tolerant to acetic acid, either isolated from natural environments or specifically engineered for this effect, represent a unique reservoir of information that could increase our understanding of acetic acid tolerance and contribute to the design of additional tolerance mechanisms. In this article, the mechanisms underlying the acetic acid tolerance exhibited by several bacterial strains are reviewed, with emphasis on the knowledge gathered in acetic acid bacteria and E. coli. A comparison of how these bacterial adaptive responses to acetic acid stress fit to those described in the yeast Saccharomyces cerevisiae is also performed. A systematic comparison of the similarities and dissimilarities of the ways by which different microbial systems surpass the deleterious effects of acetic acid toxicity has not been performed so far, although such exchange of knowledge can open the door to the design of novel approaches aiming the development of acetic acid-tolerant strains with increased industrial robustness in a synthetic biology perspective. PMID:26142387

  6. The Minimal Buffering Requirements of Congestion Controlled Interactive Multimedia Applications

    E-print Network

    Walpole, Jonathan

    The Minimal Buffering Requirements of Congestion Controlled Interactive Multimedia Applications to study the minimal buffering requirements of congestion controlled multimedia applications. Applications in the Internet must use congestion control protocols, which vary transmission rates according to network

  7. 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...

  8. Superconducting Bi-Ca-Sr-Cu oxide thin films by spray pyrolysis of metal acetates

    NASA Astrophysics Data System (ADS)

    Vaslow, Dale F.; Dieckmann, Gunter H.; Elli, David Dawson; Ellis, Arthur B.; Holmes, D. Scott; Lefkow, Anthony; MacGregor, Mark; Nordman, James E.; Petras, Michael F.; Yang, Yifeng

    1988-07-01

    Superconducting Bi-Ca-Sr-Cu oxide thin films have been prepared on ZrO2-coated silicon (111) wafers by spray pyrolysis of metal acetate precursors followed by rapid annealing to 850 °C in air. Resistivity measurements indicate a broad superconducting transition with Tc onset near 90 K and zero resistivity below 60 K. The films are highly oriented with the c axis normal to the substrate surface and can be indexed to a tetragonal structure with lattice parameters of a=3.832(1) Å and c=30.78(5) Å. Both x-ray photoelectron spectroscopy and x-ray diffraction measurements indicate the loss of Ca to the ZrO2 buffer layer.

  9. Removal of acetic acid from simulated hemicellulosic hydrolysates by emulsion liquid membrane with organophosphorus extractants.

    PubMed

    Lee, Sang Cheol

    2015-09-01

    Selective removal of acetic acid from simulated hemicellulosic hydrolysates containing xylose and sulfuric acid was attempted in a batch emulsion liquid membrane (ELM) system with organophosphorus extractants. Various experimental variables were used to develop a more energy-efficient ELM process. Total operation time of an ELM run with a very small quantity of trioctylphosphine oxide as the extractant was reduced to about a third of those required to attain almost the same extraction efficiency as obtained in previous ELM works without any extractant. Under specific conditions, acetic acid was selectively separated with a high degree of extraction and insignificant loss of xylose, and its purity and enrichment ratio in the stripping phase were higher than 92% and 6, respectively. Also, reused organic membrane solutions exhibited the extraction efficiency as high as fresh organic solutions did. These results showed that the current ELM process would be quite practical. PMID:26056774

  10. Stream water responses to timber harvest: Riparian buffer width effectiveness

    Microsoft Academic Search

    Barton D. Clinton

    2011-01-01

    Vegetated riparian buffers are critical for protecting aquatic and terrestrial processes and habitats in southern Appalachian ecosystems. In this case study, we examined the effect of riparian buffer width on stream water quality following upland forest management activities in four headwater catchments. Three riparian buffer widths were delineated prior to cutting; 0m (no-buffer), 10m, and 30m, and one reference site

  11. Exact analysis of asymmetric polling systems with single buffers

    Microsoft Academic Search

    T. Takine; Y. Takahashi; T. Hasegawa

    1988-01-01

    A unified approach to general asymmetric polling systems with a single buffer at each station is presented. Two variations of single-buffer polling system are considered: the conventional system and the buffer-relaxation system. In the conventional system, a new massage is not allowed to queue until the previous message has been completely transmitted, while in the buffer-relaxation system, a newly arriving

  12. Studies of Solution Deposited Cerium Oxide Thin Films on Textured Ni-Alloy Substractes for YBCO Superconductor

    SciTech Connect

    Stewart, Erin L [ORNL; Bhuiyan, Md S [ORNL; Sathyamurthy, Srivatsan [ORNL; Paranthaman, Mariappan Parans [ORNL

    2006-01-01

    Cerium oxide (CeO2) buffer layers play an important role for the development of YBa2Cu3O7-x (YBCO) based superconducting tapes using the rolling assisted biaxially textured substrates (RABiTS) approach. The chemical solution deposition (CSD) approach has been used to grow epitaxial CeO2 films on textured Ni-3 a 4% W alloy substrates with various starting precursors of ceria. Precursors such as cerium acetate, cerium acetylacetonate, cerium 2-ethylhexanoate, cerium nitrate, and cerium trifluoroacetate were prepared in suitable solvents. The optimum growth conditions for these cerium precursors were Ar-4% H2 gas processing atmosphere, solution concentration levels of 0.2-0.5 M, a dwell time of 15 min, and a process temperature range of 1050-1150 degrees C. X-ray diffraction, AFM, SEM, and optical microscopy were used to characterize the CeO2 films. Highly textured CeO2 layers were obtained on Ni-W substrates with both cerium acetate and cerium acetylacetonate as starting precursors. YBCO films with a Jc of 1.5 MA/cm2 were obtained on cerium acetylacetonate-based CeO2 films with sputtered YSZ and CeO2 cap layers.

  13. Studies of solution deposited cerium oxide thin films on textured Ni-alloy substrates for YBCO superconductor

    SciTech Connect

    Stewart, E. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Bhuiyan, M.S. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Sathyamurthy, S. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Paranthaman, M. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States)]. E-mail: paranthamanm@ornl.gov

    2006-06-15

    Cerium oxide (CeO{sub 2}) buffer layers play an important role for the development of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) based superconducting tapes using the rolling assisted biaxially textured substrates (RABiTS) approach. The chemical solution deposition (CSD) approach has been used to grow epitaxial CeO{sub 2} films on textured Ni-3 at.% W alloy substrates with various starting precursors of ceria. Precursors such as cerium acetate, cerium acetylacetonate, cerium 2-ethylhexanoate, cerium nitrate, and cerium trifluoroacetate were prepared in suitable solvents. The optimum growth conditions for these cerium precursors were Ar-4% H{sub 2} gas processing atmosphere, solution concentration levels of 0.2-0.5 M, a dwell time of 15 min, and a process temperature range of 1050-1150 deg. C. X-ray diffraction, AFM, SEM, and optical microscopy were used to characterize the CeO{sub 2} films. Highly textured CeO{sub 2} layers were obtained on Ni-W substrates with both cerium acetate and cerium acetylacetonate as starting precursors. YBCO films with a J {sub c} of 1.5 MA/cm{sup 2} were obtained on cerium acetylacetonate-based CeO{sub 2} films with sputtered YSZ and CeO{sub 2} cap layers.

  14. Spacecraft optical disk recorder memory buffer control

    NASA Technical Reports Server (NTRS)

    Hodson, Robert F.

    1993-01-01

    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.

  15. Compatibility of buffered uranium carbides with tungsten.

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.

    1971-01-01

    Results of compatibility tests between tungsten and hyperstoichiometric uranium carbide alloys run at 1800 C for 1000 and 2500 hours. These tests compared tungsten-buffered uranium carbide with tungsten-buffered uranium-zirconium carbide. The zirconium carbide addition appeared to widen the homogeneity range of the uranium carbide, making additional carbon available for reaction. Reaction layers could be formed by either of two diffusion paths, one producing UWC2, while the second resulted in the formation of W2C. UWC2 acts as a diffusion barrier for carbon and slows the growth of the reaction layer with time, while carbon diffusion is relatively rapid in W2C, allowing equilibrium to be reached in less than 2500 hours at a temperature of 1800 C.

  16. Improving HTTP-based video performance using network flow buffering

    Microsoft Academic Search

    Jesse Steinberg; Joseph Pasquale

    2010-01-01

    We present network flow buffering, which is the use of a remote flow-regulating buffer that is deployed between a Web client and server to improve performance of HTTP-based playback of video. We show that HTTP enhanced with network flow buffering significantly improves performance, especially under high packet loss and highly variable bandwidth conditions, when compared with using either straight HTTP

  17. Load-Balanced Combined Input-Crosspoint Buffered Packet Switches

    Microsoft Academic Search

    Roberto Rojas-Cessa; Ziqian Dong

    2011-01-01

    Combined input-crosspoint buffered (CICB) switches can achieve high switching performance without speedup. However, the dedicated crosspoint buffers in a CICB switch may not be efficiently used, and throughput degradation may occur. This throughput degradation is especially observable under flows with high data rates and long distances between the line cards and the buffered crossbar. This paper introduces two load-balanced CICB

  18. An Optical Crosspoint Buffered Switching Architecture Lin Cai,1, 2

    E-print Network

    Wai, Ping-kong Alexander

    of the critical components of optical packet switching. Current optical buffers are mainly based on fiber delay buffers for output contention resolution have been proposed [1-3]. These switches focus on using optical if the optical fiber transmission rate is high. To have proper buffer scheduling, the central scheduler has

  19. Nearly optimal FIFO buffer management for DiffServ

    Microsoft Academic Search

    Zvi Lotker; Boaz Patt-Shamir

    2002-01-01

    We consider a FIFO buffer with finite storage space. An arbitrary input stream of packets arrives at the buffer, but the output stream rate is bounded, so overflows may occur. Motivated by DiffServ, we assume that each packet has value either 1 or ?, for some ? > 1. The buffer management task is to decide which packets to drop

  20. Buffer Layer Assisted Laser Patterning of Metals on Surfaces

    E-print Network

    Asscher, Micha

    , variable width metallic wires. By employing laser desorption of a physisorbed buffer gas, a grating of goldBuffer Layer Assisted Laser Patterning of Metals on Surfaces Gabriel Kerner and Micha Asscher controlled metallic clusters via buffer layer assisted growth (BLAG).9-11 To create clusters, the metal

  1. Meta-Analysis of Nitrogen Removal in Riparian Buffers

    Microsoft Academic Search

    Paul M. Mayer; Steven K. Reynolds; Marshall D. McCutchen; Timothy J. Canfield

    2007-01-01

    Riparian buffers, the vegetated region adjacent to streams and wet- lands, are thought to be effective at intercepting and reducing nitrogen loads entering water bodies. Riparian buffer width is thought to be positively related to nitrogen removal effectiveness by influencing nitrogen retention or removal. We surveyed the scientific literature containing data on riparian buffers and nitrogen concentration in streams and

  2. Centralized Buffer Router with Elastic Links and Bubble Flow Control

    E-print Network

    Lee, Hsien-Hsin "Sean"

    Centralized Buffer Router with Elastic Links and Bubble Flow Control Syed Minhaj Hassan Georgia: sudha@ece.gatech.edu Abstract--While router buffers have been used as performance multipliers elastic bubble router - a router micro-architecture based on the use of centralized buffers (CB

  3. Permeation performance of Cellulose acetate propionate\\/polyvinylidine fluoride blend membranes by phase inversion

    Microsoft Academic Search

    Kuo-Liang Chuang; Ming-Chi Hsieh; Yun-Chieh Su; Hui-Hsin Tseng; Li-Luen Huang

    2010-01-01

    In this study, cellulose acetate propionate (CAP) and polyvinylidene fluoride (PVDF) were selected to prepare porous-blend membrane by wet phase inversion method. The effect of the CAP and PVDF concentration of the casting solution on membrane morphology structure and thermal stability was investigated by scanning electron microscopy (SEM) and thermal gravimetry\\/differential scanning calorimetry (TGA\\/DSC). The pure water flux by the

  4. Zinc nutrition and levels of endogenous lndole?3?acetic acid in radish shoots

    Microsoft Academic Search

    Balal Hossain; Norihiro Hirata; Yoshitaka Nagatomo; Masahito Suiko; Hiroshi Takaki

    1998-01-01

    Radish (Raphanus sativus cv. Akamaru?Hatsukadaikon) was grown for several experiments in a glasshouse with zinc (Zn) supply in the nutrient solution. Lack of Zn resulted in stunted growth and reduced leaf of radish shoots were observed. Two?dimensional thin layer chromatography (TLC) and gas chromatography?mass spectrometry (GC?MS) analysis revealed the presence of endogenous indole?3?acetic acid (IAA) in Zn?deficient radish shoots. An

  5. Optimization of buffer rod geometry using MATLAB

    Microsoft Academic Search

    Niels Hoppe; Alf Püttmer; Peter Hauptmann

    2001-01-01

    Several applications of ultrasonic techniques are limited by the signal-to-noise ratio (SNR). Transducers in these applications usually operate in the pulse-echo mode. Several transducers, especially those for high temperatures, use buffer rods. Interference of the echo signal and noise causes errors of both amplitude and phase measurement of the detected echoes. In this work we discuss the influence of major

  6. Eslicarbazepine acetate (BIA 2-093)

    Microsoft Academic Search

    Luis Almeida; Patrício Soares-da-Silva

    2007-01-01

    Summary  Eslicarbazepine acetate (ESL) [(S)-(?)-10-acetoxy-10, 11-dihydro-5H-dibenz[b,f]azepine-5-carboxamide], formerly known as BIA 2-093, is a novel central nervous system (CNS)-active compound with anticonvulsant\\u000a activity. It behaves as a voltage-gated sodium channel (VGSC) blocker and is currently under clinical development for the\\u000a treatment of epilepsy and bipolar disorder. ESL shares with carbamazepine and oxcarbazepine the dibenzazepine nucleus bearing\\u000a the 5-carboxamide substitute, but is structurally

  7. A potentiometric study of Eu 3+ complexation with acetate ligand from 25 to 170°C at P sat

    NASA Astrophysics Data System (ADS)

    Zotov, Alexander V.; Tagirov, Boris R.; Diakonov, Igor I.; Ragnarsdottir, K. Vala

    2002-10-01

    Thermodynamic properties for europium acetate (EuCH 3COO 2+ and Eu(CH 3COO) 2+) complexes were studied by potentiometry at temperatures from 25 to 170°C at the saturation pressure of water. The thermodynamic association constants (K 1 and K 2) for the reaction Eu3+ + n Acite- = EuAcn3-n. were determined by two different experimental approaches at 25 to 75°C and 75 to 170°C. Logarithms of measured association constants increase with increasing temperature, showing that Eu-Ac complexing increases as temperature rises. Log K1 for EuCH 3COO 2+ increases from 2.91 at 25°C to 4.25 at 170°C, whereas log K2 for Eu(CH 3COO) 2+ increases from 4.83 at 25°C to 7.39 at 170°C. Species distribution calculated in this study using the experimentally determined association constants suggests that in acetate-bearing solutions (?0.05 m) Eu-acetate complexes dominate over the free ion above pH of 4 to temperatures of at least 200°C. At equal total acetate and carbonate concentrations and at 25°C, the relative stability of carbonate and acetate complexes is close. However, as the temperature rises the relative stability of carbonate versus acetate complexes is model dependent.

  8. Stable acetate production in extreme-thermophilic (70°C) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens

    NASA Astrophysics Data System (ADS)

    Zhang, Fang; Zhang, Yan; Ding, Jing; Dai, Kun; van Loosdrecht, Mark C. M.; Zeng, Raymond J.

    2014-06-01

    The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in extreme-thermophilic (70°C) mixed culture fermentation. The continuous stirred tank reactor (CSTR) was stable operated during 100 days, in which acetate accounted for more than 90% of metabolites in liquid solutions. The yields of acetate, methane and biomass in CSTR were 1.5 +/- 0.06, 1.0 +/- 0.13 and 0.4 +/- 0.05 mol/mol glucose, respectively, close to the theoretical expected values. The CSTR effluent was stable and no further conversion occurred when incubated for 14 days in a batch reactor. In fed-batch experiments, acetate could be produced up to 34.4 g/L, significantly higher than observed in common hydrogen producing fermentations. Acetate also accounted for more than 90% of soluble products formed in these fed-batch fermentations. The microbial community analysis revealed hydrogenotrophic methanogens (mainly Methanothermobacter thermautotrophicus and Methanobacterium thermoaggregans) as 98% of Archaea, confirming that high temperature will select hydrogenotrophic methanogens over aceticlastic methanogens effectively. This work demonstrated a potential application to effectively produce acetate as a value chemical and methane as an energy gas together via mixed culture fermentation.

  9. 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.

  10. Foam-buffered laser-matter interactions

    SciTech Connect

    Mason, R.J.; Kopp, R.A.; Vu, H.X.; Wilson, D.C.; Goldman, S.R.; Watt, R.G.

    1997-10-01

    Recent experiments indicate that low-density foam buffer layers can significantly mitigate the perturbing effects of beam non-uniformities in direct drive laser-matter interactions. Results of a computational study with a 2D ALE code are reported here. Typical targets consisted of 50 {micro}m of 50 mg/cm{sup 3} C{sub 10}H{sub 8}O{sub 4} foam attached to a 10 {micro}m foil and covered with 250 {angstrom} of gold. These targets were exposed to {approximately} 1.2 ns, flat topped, green light pulses at {approximately} 1.4 {times} 10{sup 14} W/cm{sup 2} intensity, bearing 30 {micro}m lateral perturbations. Without the buffer layers the foils were severely disrupted after 1 ns of laser illumination. Buffering could provide stability for more than 2 ns of full shell acceleration. This study shows that the high thermal conductivity of the foam results in flattened shocks in the foam plasma, communicating a smoothed laser drive to the accelerated shells. Preheat from the gold hastens conversion of solid foam to the smoothing heated plasma.

  11. Calculated and measured [Ca(2+)] in buffers used to calibrate Ca(2+) macroelectrodes.

    PubMed

    McGuigan, John A S; Stumpff, Friederike

    2013-05-01

    The ionized concentration of calcium in physiological buffers ([Ca(2+)]) is normally calculated using either tabulated constants or software programs. To investigate the accuracy of such calculations, the [Ca(2+)] in EGTA [ethylene glycol-bis(?-aminoethylether)-N,N,N|,N|-tetraacetic acid], BAPTA [1,2-bis(o-aminophenoxy) ethane-N,N,N|,N|-tetraacetic acid], HEDTA [N-(2-hydroxyethyl)-ethylenediamine-N,N|,N|-triacetic acid], and NTA [N,N-bis(carboxymethyl)glycine] buffers was estimated using the ligand optimization method, and these measured values were compared with calculated values. All measurements overlapped in the pCa range of 3.51 (NTA) to 8.12 (EGTA). In all four buffer solutions, there was no correlation between measured and calculated values; the calculated values differed among themselves by factors varying from 1.3 (NTA) to 6.9 (EGTA). Independent measurements of EGTA purity and the apparent dissociation constants for HEDTA and NTA were not significantly different from the values estimated by the ligand optimization method, further substantiating the method. Using two calibration solutions of pCa 2.0 and 3.01 and seven buffers in the pCa range of 4.0-7.5, calibration of a Ca(2+) electrode over the pCa range of 2.0-7.5 became a routine procedure. It is proposed that such Ca(2+) calibration/buffer solutions be internationally defined and made commercially available to allow the precise measurement of [Ca(2+)] in biology. PMID:23333223

  12. Continuous processing of recombinant proteins: integration of refolding and purification using simulated moving bed size-exclusion chromatography with buffer recycling.

    PubMed

    Wellhoefer, Martin; Sprinzl, Wolfgang; Hahn, Rainer; Jungbauer, Alois

    2014-04-11

    Continuous processing of recombinant proteins was accomplished by combining continuous matrix-assisted refolding and purification by tandem simulated moving bed (SMB) size-exclusion chromatography (SEC). Recombinant proteins, N(pro) fusion proteins from inclusion bodies were dissolved with NaOH and refolded in the SMB system with a closed-loop set-up with refolding buffer as the desorbent buffer and buffer recycling of the refolding buffer of the raffinate by tangential flow filtration. For further purification of the refolded proteins, a second SMB operation also based on SEC was added. The whole system could be operated isocratically with refolding buffer as the desorbent buffer, and buffer recycling could also be applied in the purification step. Thus, a significant reduction in buffer consumption was achieved. The system was evaluated with two proteins, the N(pro) fusion pep6His and N(pro) fusion MCP-1. Refolding solution, which contained residual N(pro) fusion peptide, the cleaved autoprotease N(pro), and the cleaved target peptide was used as feed solution. Full separation of the cleaved target peptide from residual proteins was achieved at a purity and recovery in the raffinate and extract, respectively, of approximately 100%. In addition, more than 99% of the refolding buffer of the raffinate was recycled. A comparison of throughput, productivity, and buffer consumption of the integrated continuous process with two batch processes demonstrated that up to 60-fold higher throughput, up to 180-fold higher productivity, and at least 28-fold lower buffer consumption can be obtained by the integrated continuous process, which compensates for the higher complexity. PMID:24630055

  13. Enzymatic Synthesis of Isopropyl Acetate by Immobilized Bacillus cereus Lipase in Organic Medium

    PubMed Central

    Verma, Madan Lal; Azmi, Wamik; Kanwar, Shamsher Singh

    2011-01-01

    Selective production of fragrance fatty acid ester from isopropanol and acetic acid has been achieved using silica-immobilized lipase of Bacillus cereus MTCC 8372. A purified thermoalkalophilic extracellular lipase was immobilized by adsorption onto the silica. The effects of various parameters like molar ratio of substrates (isopropanol and acetic acid; 25 to 100?mM), concentration of biocatalyst (25–125?mg/mL), reaction time, reaction temperature, organic solvents, molecular sieves, and initial water activity were studied for optimal ester synthesis. Under optimized conditions, 66.0?mM of isopropyl acetate was produced when isopropanol and acetic acid were used at 100?mM: 75?mM in 9?h at 55°C in n-heptane under continuous shaking (160?rpm) using bound lipase (25?mg). Addition of molecular sieves (3?Å ×?1.5?mm) resulted in a marked increase in ester synthesis (73.0?mM). Ester synthesis was enhanced by water activity associated with pre-equilibrated saturated salt solution of LiCl. The immobilized lipase retained more than 50% of its activity after the 6th cycle of reuse. PMID:21603222

  14. Visualization of Early Events in Acetic Acid Denaturation of HIV-1 Protease: A Molecular Dynamics Study

    PubMed Central

    Borkar, Aditi Narendra; Rout, Manoj Kumar; Hosur, Ramakrishna V.

    2011-01-01

    Protein denaturation plays a crucial role in cellular processes. In this study, denaturation of HIV-1 Protease (PR) was investigated by all-atom MD simulations in explicit solvent. The PR dimer and monomer were simulated separately in 9 M acetic acid (9 M AcOH) solution and water to study the denaturation process of PR in acetic acid environment. Direct visualization of the denaturation dynamics that is readily available from such simulations has been presented. Our simulations in 9 M AcOH reveal that the PR denaturation begins by separation of dimer into intact monomers and it is only after this separation that the monomer units start denaturing. The denaturation of the monomers is flagged off by the loss of crucial interactions between the ?-helix at C-terminal and surrounding ?-strands. This causes the structure to transit from the equilibrium dynamics to random non-equilibrating dynamics. Residence time calculations indicate that denaturation occurs via direct interaction of the acetic acid molecules with certain regions of the protein in 9 M AcOH. All these observations have helped to decipher a picture of the early events in acetic acid denaturation of PR and have illustrated that the ?-helix and the ?-sheet at the C-terminus of a native and functional PR dimer should maintain both the stability and the function of the enzyme and thus present newer targets for blocking PR function. PMID:21738569

  15. Plasmacatalytic removal of lead acetate assisted by precipitation.

    PubMed

    Haddou, Nabila; Ghezzar, Mouffok Redouane; Abdelmalek, Fatiha; Ognier, Stéphanie; Martel, Marc; Addou, Ahmed

    2014-07-01

    The Gliding Arc Discharge (GAD) is an efficient non-thermal plasma technique able to degrade organic compounds dispersed in water at atmospheric pressure. The degradation of the organometallic lead acetate (PbAc) in aqueous solution was performed by two distinct plasmageneous processes: GAD and GAD/TiO2. The global oxidation of the organic matter was followed by Chemical Oxygen Demand (COD) and the mineralization was determined by the Total Organic Carbon (TOC). The Pb(2+) ions released during the degradation process were measured by Atomic Absorption Spectroscopy (AAS). For 2h of GAD treatment, the degradation rate of PbAc (10mM) reached 83% and for the same duration of GAD/TiO2 process ([TiO2]=1gL(-1)), it reached 93%. The release of Pb(2+) ions in the solution was respectively of 95% and 57% for GAD and GAD/TiO2 processes. The released Pb(2+) ions were removed by precipitation process in a basic medium at pH=11.1. A reaction mechanism was proposed to explain the PbAc molecule degradation and the Pb(2+) elimination. PMID:24462087

  16. Platinum acetate blue: synthesis and characterization.

    PubMed

    Cherkashina, Natalia V; Kochubey, Dmitry I; Kanazhevskiy, Vladislav V; Zaikovskii, Vladimir I; Ivanov, Vladimir K; Markov, Alexander A; Klyagina, Alla P; Dobrokhotova, Zhanna V; Kozitsyna, Natalia Yu; Baranovsky, Igor B; Ellert, Olga G; Efimov, Nikolai N; Nefedov, Sergei E; Novotortsev, Vladimir M; Vargaftik, Michael N; Moiseev, Ilya I

    2014-08-18

    Platinum acetate blue (PAB) of the empirical formula Pt(OOCMe)2.5±0.25, a byproduct in the synthesis of crystalline platinum(II) acetate Pt4(OOCMe)8, is an X-ray amorphous substance containing platinum in the oxidation state between (II) and (III). Typical PAB samples were studied with X-ray diffraction, differential thermal analysis-thermogravimetric, extended X-ray absorption fine structure, scanning electron microscopy, transmission electron microscopy, magnetochemistry, and combined quantum chemical density functional theory-molecular mechanics modeling to reveal the main structural features of the PAB molecular building blocks. The applicability of PAB to the synthesis of platinum complexes was demonstrated by the preparation of the new homo- and heteronuclear complexes Pt(II)(dipy)(OOCMe)2 (1), Pt(II)(?-OOCMe)4Co(II)(OH2) (2), and Pt(III)2(OOCMe)4(O3SPhMe)2 (3) with the use of PAB as starting material. PMID:25102316

  17. [Ulipristal acetate, 5mg: a new alternative].

    PubMed

    Monleón Sancho, Javier; Romaguera, Eugenia; Romero, Ainhoa; Higueras, Gema; Morcillo, Inmaculada; Fuster, Sonia

    2013-07-01

    Fibroids have a high prevalence (approaching 50%) in the female population. Although they are a benign entity, they represent a health problem of considerable magnitude, causing hemorrhaging, pain and sterility. Surgical treatment is currently safe and effective, but in recent decades numerous less invasive alternatives have appeared, such as uterine artery embolization and thermal ablation (HIFU and radiofrequency). New possibilities for medical treatment have also emerged, such as GnRh analogues, aromatase inhibitors and selective progesterone receptor modulators (SPRMs). SPRMs act through progesterone receptors and behave as agonists or antagonists in various target organs. Among them, ulipristal acetate (UA) inhibits the proliferation and induction of apoptosis and cell death pathways in leiomyoma cells, translating at the clinical level to smaller fibroids and lower uterine volumes, with no significant side effects. UA also produces amenorrhea in most patients. Randomized, phase III (PEARL I and II) clinical trials have shown the efficacy and security of UA versus placebo and leuprolide acetate (LA). UA is similar to LA, and superior to placebo in controlling bleeding and decreasing the size of the fibroid, with fewer side effects than LA. The safety and tolerance of UA have been satisfactory. UA is a reality in the preoperative treatment of fibroids, with broad potential for further development. PMID:24314567

  18. Atmospheric formic and acetic acids in Venezuela

    NASA Astrophysics Data System (ADS)

    Sanhueza, Eugenio; Figueroa, Luis; Santana, Magaly

    Gas, phase and rain concentrations of HCOOH and CH 3COOH have been measured at various sites in the savannah climatic region, a cloud forest site and a coastal site in Venezuela. Gas phase and rain water were sampled using the aqueous scrubber technique and a wet only collector, respectively. Analyses were made by ion chromatography. The results indicate that formic and acetic acids are important components of the Venezuelan atmosphere. They are homogeneously distributed, suggesting a widespread source. Boundary layer concentrations during the dry season (HCOOH, 1.8 ppbv; CH 3COOH, 1.25 ppbv) are higher than in the wet season (HCOOH, 1.0 ppbv; CH 3COOH, 0.7 ppbv), mainly due to a longer lifetime of the acid during the dry season (˜6 days) compared with the wet season (˜2 days). The overall concentrations in rain are 7.0 and 4.0 ?M for formic and acetic acids, respectively. The estimated annual total depositions are: HCOOH, 17 mmol m -2 yr -1 and CH 3COOH,10 mmol m -2 yr -1; around half of the acids are removed by dry deposition. It is established that a larger source (˜1.8 times) of both acids is present during the wet season. We speculate that atmospheric oxidation of hydrocarbons should be the main source of HCOOH and CH 3COOH in the Venezuelan atmosphere; soil emissions could make a significant contribution during the dry season.

  19. Concentrated Flow through a Riparian Buffer: A Case Study

    NASA Astrophysics Data System (ADS)

    Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

    2005-05-01

    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.

  20. Studies on the compatibility and specific interaction in cellulose acetate hydrogen phthalate (CAP) and poly methyl methacrylate (PMMA) blend

    Microsoft Academic Search

    V Rao; P. V Ashokan; M. H Shridhar

    1999-01-01

    Compatibility of cellulose acetate hydrogen phthalate (CAP) and poly methyl methacrylate (PMMA) has been investigated by solution viscometric, ultrasonic and differential scanning calorimetric (DSC) methods. From viscosity measurements, Krigbaum and Wall polymer–polymer interaction parameter is evaluated. Ultrasonic velocity and adiabatic compressibilites versus blend composition are plotted, and found to be linear. Tg values are calculated using Gordon–Taylor and Fox equations.

  1. Resolving the electrospinnability zones and diameter prediction for the electrospinning of the gelatin/water/acetic acid system.

    PubMed

    Erencia, Marisa; Cano, Francisco; Tornero, Jose A; Macanás, Jorge; Carrillo, Fernando

    2014-06-24

    The development of suitable biomimetic scaffolds is a fundamental requirement of tissue engineering. Although electrospinning has emerged as an effective method for producing such scaffolds of nanometer-sized fibers, the influence of solution characteristics on the morphology of the resulting nanofibers depends on each polymer solution system. In this study, gelatin nanofibers and microfibers were prepared via electrospinning using mixtures of water and acetic acid at different ratios as solvents. The viscosities of gelatin solutions before electrospinning were analyzed and two different behaviors were found as a function of the solvent composition, taking into account classic models of polymer science. A power law relationship between viscosity and gelatin concentration was found for each solvent system, and an empirical model including the influence of acetic acid was obtained for aqueous systems. Moreover, a ternary diagram considering gelatin, water, and acetic acid mass fractions was constructed as a tool to establish the electrospinnability domains in terms of fiber occurrence and morphology. Also, the isodiametric curves were defined in the fibers region. Finally, in order to correlate the diameter of electrospun nanofibers and the electrospinnability zones, the Berry number was used. However, as its only allows the range of electrospinnability to be established for a fixed solvent composition, a new dimensionless parameter (Bemod) was suggested to take into account all the acetic acid aqueous solutions as a single solvent. PMID:24870557

  2. Studies of ultrasonic velocity in aqueous solutions of electrolytes

    Microsoft Academic Search

    M. Pancholy; S. P. Singal

    1963-01-01

    Summary  Measurements of sound velocity in aqueous solutions of sodium formate, sodium acetate, sodium propionate, sodium iso-valerate,\\u000a calcium formate, calcium acetate, calcium propionate, lead acetate and zinc sulphate support Eucken’s theory which envisages\\u000a a decrease in the number of aggregates of water molecules as the temperature rises. The other derived characteristics such\\u000a as adiabatic compressibility, apparent molal compressibility and apparent molal

  3. Buffer for a gamma-insensitive optical sensor with gas and a buffer assembly

    DOEpatents

    Kruger, H.W.

    1994-05-10

    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.

  4. Effects of poly(ethylene oxide) and ZnO nanoparticles on the morphology, tensile and thermal properties of cellulose acetate nanocomposite fibrous film

    Microsoft Academic Search

    Chonticha Pittarate; Tipaporn Yoovidhya; Walaiporn Srichumpuang; Narupol Intasanta; Saowakon Wongsasulak

    2011-01-01

    A bio-based fibrous film intended to be used as a food-packaging component was electrospun from blend solutions of cellulose acetate (CA) in neat acetic acid and poly(ethylene oxide) (PEO) in 90% ethanol. The CA\\/PEO blend ratios were varied to determine the effects of PEO on the morphology, moisture-adsorption and tensile properties of the blended fibrous films. Zinc oxide nanoparticles (ZnO

  5. Determination of rate constants for the reactions of H, OH and eaq with indole-3-acetic acid and other plant hormones

    Microsoft Academic Search

    R. S. Shetiya; K. N. Rao; J. Shankar

    1972-01-01

    In the radiolysis of aqueous solutions of indole, indole-3-acetic acid, indole-3-propionic acid, 1-naphthylacetic acid and phenylacetic acid, the absolute rate constants of their reactions with H and OH have been determined by competition kinetics using 2-propanol as the competitor. Hydrated electron reaction rate constants have been determined for indoie, indole-3-acetic acid and indole-3-propionic acid at pH = 11 using the

  6. Liquid-phase oxidation of propylene to propylene glycol acetates over Pd\\/C and Pt?Pd\\/C: Effect of platinum on catalyst activity and metal dispersity

    Microsoft Academic Search

    A. V. Karandin; E. V. Gusevskaya; V. A. Likholobov; E. M. Moroz; V. I. Zaikovskii

    1992-01-01

    Kinetics of oxidation of propylene to propylene glycol and its acetates in acetic acid solutions of lithium nitrate over Pd\\/C and Pd?Pt\\/C catalysts has been studied. Catalysts were investigated using X-ray phase analysis and electron microscopy. Platinum introduction into catalyst increases the metal dispersity and the catalyst stability but produces no effect on the nature of surface sites active in

  7. Production of low-cost calcium magnesium acetate (CMA) as an environmentally friendly deicer from cheese whey

    SciTech Connect

    Yang, S.T.; Zhu, H.; Li, Y.; Tang, I.C. [Ohio State Univ., Columbus, OH (United States)

    1993-12-31

    About 28 billion lbs of cheese whey are being wasted in the US because of the high biological oxygen demand (BOD) of whey, disposing of surplus whey is a pollution problem. An innovative, wide-scale solution to the whey disposal problem is to use whey as a zero- or low-cost feedstock for the production of an environmentally safe, noncorrosive, road deicer-calcium magnesium acetate (CMA). CMA can be used to replace some of the 10 to 14 million tons road salt used in the North America for deicing. A novel anaerobic fermentation process is developed to produce calcium magnesium acetate (CMA) from whey permeate. A co-culture consisting of homolactic (S. lactis) and homoacetic (C. formicoaceticum) bacteria was used to convert whey lactose to lactate and then to acetate in continuous, immobilized cell bioreactors. The acetate yield from lactose was {approximately}95% (wt/wt), and the final concentration of acetic acid was 4%. The acetic acid present in the fermentation broth can be recovered by solvent-extraction with a tertiary amine and reacted with dolomitic lime (Ca/MgO) to form a concentrated (>25%) CMA solution. About 25 tons CMA can be produced from a plant processing 1 million lbs whey permeate (4.5% lactose) per day. The production costs are estimated at {approximately}$220/ton CMA, which is only about one third of the present market price for CMA deicer. Therefore, about 0.8 million tons/yr CMA deicer can be produced from the currently unused whey. This will partially fulfill market demand for economically and environmentally sound chemicals for roadway deicing. This also will provide a viable solution to the whey disposal problem currently facing many dairies in the North America.

  8. Hybrid Silicon AWG Lasers and Buffers

    NASA Astrophysics Data System (ADS)

    Kurczveil, Geza

    Silicon photonics promises the low cost integration of optical components with CMOS electronics thus enabling optical interconnects in future generation processors. The hybrid silicon platform (HSP) is one approach to make optically active components on silicon. While many optical components on the HSP have been demonstrated, few photonic integrated circuits (PICs), consisting of multiple elements, have been demonstrated. In this dissertation, two Hybrid Silicon PICs and their building blocks will be presented. The first PIC to be presented is a multiwavelength laser based on an AWG. It consists of Fabry-Perot cavities integrated with hybrid silicon amplifiers and an intracavity filter in the form of an AWG with a channel spacing of 360 GHz. Four-channel lasing operation is shown. Single-sided fiber-coupled output powers as high as 35 µW are measured. The SMSR is as high as 35 dB. Various device characteristics are compromised as the AWG was attacked during the III-V process, thus showing the need to properly protect passive components during III-V processing. The second PIC to be presented is a fully integrated optical buffer. The device consists of a hybrid silicon switch, a 1.1 m long silicon waveguide, and cascaded hybrid silicon amplifiers. The passive delay line is protected by dielectric layers to limit passive losses to 0.5 dB/cm. Noise filters in the form of saturable absorbers are integrated in the buffer to allow for a larger number of recirculations in the delay line compared to a delay without filters. Tapers are used to transition the mode from the passive region to the hybrid region with losses as low as 0.22 dB per transition and reflectivities below -35 dB. Error free operation of the hybrid silicon switch is demonstrated in all four paths. The integrated buffer failed due to low yield, showing the current limitations of the HSP.

  9. Improved textured La 2Zr 2O 7 buffer on La 3TaO 7 seed for all-MOD Buffer/YBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Parans Paranthaman, M.; Bhuiyan, M. S.; Sathyamurthy, S.; Heatherly, L.; Cantoni, C.; Goyal, A.

    2008-09-01

    The overall purpose of this research is to develop a potentially low-cost, high throughput, high yield, manufacturing process for buffer deposition, and to gain a fundamental understanding of buffer layers required for an all metal-organic deposition (MOD) based chemical solution approach. This understanding is critical to the development of a reliable, robust, low-cost, long-length manufacturing process of 2G wires. The standard RABiTS architectures consists of a starting template of biaxially textured Ni-W (5 at.%) substrate with a seed layer of Y 2O 3, a barrier layer of YSZ, and a CeO 2 cap. In this three-layer architecture, all the buffers are deposited using reactive sputtering. We have recently demonstrated that the barrier properties and the performance of MOD La 2Zr 2O 7 (LZO) match that of sputtered YSZ layers. In this work, the texture of MOD LZO was also improved by inserting a sputtered Y 2O 3 seed layer on which LZO grows without any degradation of texture. Significant improvement in the texture of sputtered Y 2O 3 seeds on NiW substrates is usually observed which is then transferred to the LZO layer. A key challenge for an all-solution approach is to replace the sputtered seed layer with a possible MOD seed layer with improved texture and on which no degradation of LZO texture occurs. Very recently, we have grown MOD La 3TaO 7 (LTO) seeds directly on biaxially textured Ni-W (3 at.%) with improved texture. In this study, we report a systematic investigation of the growth MOD LZO barrier layer on MOD LTO seeds. Preliminary results show that it is possible to grow MOD LZO with improved texture on MOD LTO seeds. This approach could be potentially used for future all MOD buffer/YBCO coated conductors.

  10. ZnS/Zn(O,OH)S-based buffer layer deposition for solar cells

    DOEpatents

    Bhattacharya, Raghu N. (Littleton, CO)

    2009-11-03

    The invention provides CBD ZnS/Zn(O,OH)S and spray deposited ZnS/Zn(O,OH)S buffer layers prepared from a solution of zinc salt, thiourea and ammonium hydroxide dissolved in a non-aqueous/aqueous solvent mixture or in 100% non-aqueous solvent. Non-aqueous solvents useful in the invention include methanol, isopropanol and triethyl-amine. One-step deposition procedures are described for CIS, CIGS and other solar cell devices.

  11. Recovery of Escherichia coli ATCC 25922 in phosphate buffered saline after treatment with high hydrostatic pressure

    Microsoft Academic Search

    Shigenobu Koseki; Kazutaka Yamamoto

    2006-01-01

    Escherichia coli ATCC 25922 in phosphate buffered saline solution (PBS, pH 7.1, 108 CFU\\/ml) was inactivated by high hydrostatic pressure (HHP, 400 to 600 MPa) treatment at 25 °C for 10 min. Colonies of E. coli were not detected on non-selective plate count agar immediately after a HHP-treatment of at least 550 MPa. E. coli subjected to at least 500 MPa in PBS were incubated at

  12. Buffer layers and articles for electronic devices

    DOEpatents

    Paranthaman, Mariappan P.; Aytug, Tolga; Christen, David K.; Feenstra, Roeland; Goyal, Amit

    2004-07-20

    Materials for depositing buffer layers on biaxially textured and untextured metallic and metal oxide substrates for use in the manufacture of superconducting and other electronic articles comprise RMnO.sub.3, R.sub.1-x A.sub.x MnO.sub.3, and combinations thereof; wherein R includes an element selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, and A includes an element selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Ra.

  13. Photoluminescence of cellulose acetate and silica sphere composite

    NASA Astrophysics Data System (ADS)

    Kang, Kwang-Sun

    2014-08-01

    Strong blue and green light emission has been observed from the cellulose acetate (CA) and silica sphere composite. Two different amounts of silica spheres were mixed in the CA solution to fabricate large area super-hydrophobic films. The silica spheres and CA solution ratios were 0.07:4.0 (SSCA-A) and 0.14:4.0 (SSCA-B). The milky color solution of SSCA-A and SSCA-B slowly turned to light yellow and red, respectively, with the time passed. The colors became intense yellow and red for the SSCA-A and SSCA-B, respectively, after 38 days. FTIR spectra show more absorption at 3478 cm-1 corresponding sbnd OH stretching vibration, at 2963 cm-1 caused by sbnd CH stretching vibration, at 1746 and 1713 cm-1 representing the Cdbnd O stretching vibration, and at 1100 cm-1 corresponding sbnd Rsbnd OH and Sisbnd Osbnd Si stretching vibration for CA and silica. Therefore, aged SSCA-A and SSCA-B have more sbnd OH, sbnd CH, sbnd Cdbnd O, and Sisbnd Osbnd Si groups than pure CA. UV-visible spectra show the absorption peaks at 410 nm for both SSCA-A and SSCA-B. Photoluminescence (PL) peaks were shifted toward longer wavelength with the increase of the excitation wavelength and became maximum at approximately 470 nm with excitation wavelength at 400 nm for the SSCA-A. There were two maximum luminescence peaks at 470 and 530 nm with the excitation wavelength at 400 and 470 nm, respectively, for the SSCA-B. The luminescence peak shift was due to the multiple emission center proved by the different excitation energy.

  14. Ulipristal acetate: a new emergency contraceptive.

    PubMed

    Sullivan, Jade L; Bulloch, Marilyn N

    2011-07-01

    Ulipristal acetate (UPA) is a newly developed emergency contraceptive currently available in the USA and Europe. It is approved as a 30 mg one-time dose taken within 120 h (5 days) of unprotected intercourse or failed contraception. This selective progesterone receptor modulator appears to be more effective than the levonorgestrel-containing emergency contraceptive, which must be taken within 72 h of unprotected intercourse. According to pharmacodynamic trials, UPA delays follicular maturation and ovulation. In addition, UPA may modulate the endometrium. Both Phase III clinical trials found that UPA does not lose efficacy within the 120-h dosing interval. Throughout all phases of clinical studies, UPA was shown to be well tolerated with only minimal adverse drug reactions, all of which are similar to competitor therapies. PMID:22114852

  15. Leuprolide acetate treatment of catamenial pneumothorax.

    PubMed

    Garris, P D; Sokol, M S; Kelly, K; Whitman, G F; Plouffe, L

    1994-01-01

    A 35-year-old nulligravid female with a 20 pack year history of smoking and continuous OC use since age 16 presented with recurrent pneumothoraces coinciding with the onset of menses at age 28. At that time she underwent a right partial pleurectomy and lobectomy, which demonstrated bullous disease but no glandular or stromal elements. Although catamenial respiratory discomfort persisted while on OCs, no pneumothoraces were documented until age 33 at which time she was given the diagnosis of catamenial pneumothorax. A diagnostic laparoscopy failed to demonstrate endometriosis or the presence of diaphragmatic defects. In an effort to preserve her fertility, she began a course of LA-GnRH-a therapy with depot LA. Because of disabling vasomotor and emotional side effects, continuous conjugated estrogens and MPA acetate were given as add-back therapy. She has remained symptom and side effect free for over 2 years on this regimen. PMID:8293833

  16. 4-Carbamoylpiperidinium phenyl-acetate hemihydrate.

    PubMed

    Smith, Graham; Wermuth, Urs D

    2010-01-01

    The asymmetric unit of the title compound, C(6)H(13)N(2)O(+)·C(8)H(7)O(2) (-)·0.5H(2)O, comprises two isonipecotamide cations, two phenyl-acetate anions and a water mol-ecule of solvation. The hydrogen-bonding environments for both sets of ion pairs are essentially identical with the piperidinium and amide 'ends' of each cation involved in lateral heteromolecular hydrogen-bonded cyclic N-H?O associations [graph set R(2) (2)(11)] which incorporate a single carboxyl O-atom acceptor. These cyclic motifs enclose larger R(5) (5)(21) cyclic systems, forming sheet substructures which lie parallel to (101) and are linked across b by the single water mol-ecule via water O-H?O(c) (c = carboxylate) associations, giving a duplex-sheet structure. PMID:21589544

  17. 4-Carbamoylpiperidinium phenyl­acetate hemihydrate

    PubMed Central

    Smith, Graham; Wermuth, Urs D.

    2010-01-01

    The asymmetric unit of the title compound, C6H13N2O+·C8H7O2 ?·0.5H2O, comprises two isonipecotamide cations, two phenyl­acetate anions and a water mol­ecule of solvation. The hydrogen-bonding environments for both sets of ion pairs are essentially identical with the piperidinium and amide ‘ends’ of each cation involved in lateral heteromolecular hydrogen-bonded cyclic N—H?O associations [graph set R 2 2(11)] which incorporate a single carboxyl O-atom acceptor. These cyclic motifs enclose larger R 5 5(21) cyclic systems, forming sheet substructures which lie parallel to (101) and are linked across b by the single water mol­ecule via water O—H?Oc (c = carboxylate) associations, giving a duplex-sheet structure. PMID:21589544

  18. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

    NASA Technical Reports Server (NTRS)

    Reinecke, D. M.; Bandurski, R. S.

    1988-01-01

    Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

  19. Damage tolerance of woven graphite-epoxy buffer strip panels

    NASA Technical Reports Server (NTRS)

    Kennedy, John M.

    1990-01-01

    Graphite-epoxy panels with S glass buffer strips were tested in tension and shear to measure their residual strengths with crack-like damage. The buffer strips were regularly spaced narrow strips of continuous S glass. Panels were made with a uniweave graphite cloth where the S glass buffer material was woven directly into the cloth. Panels were made with different width and thickness buffer strips. The panels were loaded to failure while remote strain, strain at the end of the slit, and crack opening displacement were monitoring. The notched region and nearby buffer strips were radiographed periodically to reveal crack growth and damage. Except for panels with short slits, the buffer strips arrested the propagating crack. The strength (or failing strain) of the panels was significantly higher than the strength of all-graphite panels with the same length slit. Panels with wide, thick buffer strips were stronger than panels with thin, narrow buffer strips. A shear-lag model predicted the failing strength of tension panels with wide buffer strips accurately, but over-estimated the strength of the shear panels and the tension panels with narrow buffer strips.

  20. Raj JainThe Ohio State University 96-0517R1 Buffer Requirements96-0517R1 Buffer Requirements96-0517R1 Buffer Requirements

    E-print Network

    Jain, Raj

    Raj JainThe Ohio State University 1 96-0517R1 Buffer Requirements96-0517R1 Buffer Requirements96, Rohit Goyal, Sonia Fahmy TheOhioStateUniversity SaragurM.Srinidhi SterlingSoftwareandNASALewisResearchCenter Contact: Jain@CIS.Ohio-State.Edu http://www.cis.ohio-state.edu/~Jain/ #12;Raj JainThe Ohio State

  1. Analysis of the stable carbon isotope composition of formic and acetic acids.

    PubMed

    Lee, Xinqing; Zhang, Like; Huang, Daikuan; An, Ning; Yang, Fang; Jiang, Wei; Fang, Bin

    2013-05-15

    Formic and acetic acids are ubiquitous in the environment and in many biological processes. Analysis of the stable carbon isotope composition (?(13)C) of formic and acetic acids is important to understanding their biogeochemical cycles. However, it has been faced with poor accuracy and high detection limits due to their low carbon number, high hydrophilicity, and semi-volatility. Here we developed an analytical technique by needle trap and gas chromatography-isotope ratio mass spectrometry (GC-IRMS). The organic acids in aqueous solution were extracted using a NeedlEx needle through purge-and-trap and were analyzed by GC-IRMS for ?(13)C. The procedures incur no isotope fractionation. Defined as the point at which the mean ?(13)C is statistically the same as the given value and the analytical error starts rising, the method's detection limits are 200 and 100 mg/L for formic and acetic acids, respectively, with an uncertainty of approximately 0.5‰ in direct extraction and analysis. They were lowered to 1 mg/L with precision of 0.9‰ after samples were subjected to preconcentration. The method was successfully applied to natural samples as diverse as precipitation, vinegars, ant plasma, and vehicle exhaust, which vary considerably in concentration and matrix of the organic acids. It is applicable to the organic acids in not only aqueous solution but also gaseous phase. PMID:23395975

  2. Controlled release of triprolidine using ethylene-vinyl acetate membrane and matrix systems.

    PubMed

    Shin, Sang-Chul; Lee, Hyun-Jin

    2002-09-01

    The studies on the permeability of triprolidine through ethylene-vinyl acetate (EVA) copolymer membrane using two-chamber diffusion cell was carried out to develop the controlled delivery system. To evaluate the effect of drug concentration in reservoir, polyethylene glycol (PEG) 400 was added to saline solution as a solubilizer and a sink condition was maintained in the receptor solution. The permeation rate of drug through EVA membrane was proportional to PEG 400 volume fraction. A linear relationship existed between the permeation rate and the reciprocal of the membrane thickness. Triprolidine-containing matrix was fabricated with EVA copolymer to control the release of the drug. The plasticizers was added for preparing the pore structure of EVA membranes to increase the drug release. The effects of PEG 400, vinyl acetate (VA) contents of EVA, membrane thickness, drug concentration, temperature, and plasticizers, on drug release were studied. The release rate of drug from the EVA matrix increased with PEG 400 volume fraction, increased temperature and drug loading doses. An increased vinyl acetate comonomer content in EVA membrane increased the drug release rate and permeability coefficient. Among the plasticizers used such as alkyl citrates and phthalates, tetra ethyl citrate showed the best enhancing effects showing the enhancement factor of 1.88. The release of triprolidine from the EVA matrix follows a diffusion controlled model, where the quantity released per unit area is proportional to the square root of time. The controlled release of triprolidine could be achieved using the EVA polymer including the plasticizer. PMID:12191692

  3. Leaching of spent lead acid battery paste components by sodium citrate and acetic acid.

    PubMed

    Zhu, Xinfeng; He, Xiong; Yang, Jiakuan; Gao, Linxia; Liu, Jianwen; Yang, Danni; Sun, Xiaojuan; Zhang, Wei; Wang, Qin; Kumar, R Vasant

    2013-04-15

    A sustainable method, with minimal pollution and low energy cost in comparison with the conventional smelting methods, is proposed for treating components of spent lead-acid battery pastes in aqueous organic acid(s). In this study, PbO, PbO2, and PbSO4, the three major components in a spent lead paste, were individually reacted with a mixture of aqueous sodium citrate and acetic acid solution. Pure lead citrate precursor of Pb3(C6H5O7)2 · 3H2O is the only product crystallized in each leaching experiment. Conditions were optimized for individual lead compounds which were then used as the basis for leaching real industrial spent paste. In this work, efficient leaching process is achieved and raw material cost is reduced by using aqueous sodium citrate and acetic acid, instead of aqueous sodium citrate and citric acid as reported in a pioneering hydrometallurgical method earlier. Acetic acid is not only cheaper than citric acid but is also more effective in aiding dissolution of the lead compounds thus speeding up the leaching process in comparison with citric acid. Lead citrate is readily crystallized from the aqueous solution due to its low solubility and can be combusted to directly produce leady oxide as a precursor for making new battery pastes. PMID:23500418

  4. Permeation study of five formulations of alpha-tocopherol acetate through human cadaver skin.

    PubMed

    Mahamongkol, Hansa; Bellantone, Robert A; Stagni, Grazia; Plakogiannis, Fotios M

    2005-01-01

    Alpha-tocopherol (AT) is the vitamin E homologue with the highest in vivo biological activity. AT protects against the carcinogenic and mutagenic activity of ionizing radiation and chemical agents, and possibly against UV-induced cutaneous damage. For stability consideration, alpha-tocopherol is usually used as its prodrug ester, alpha-tocopherol acetate (ATA), which once absorbed into the skin is hydrolyzed to alpha-tocopherol, the active form. The objective of this research was to characterize in vitro the permeation properties of ATA from various solutions and gel formulations. Permeation studies were conducted using modified Franz diffusion cells and human cadaver skin as the membrane. Specifically, 5% (w/w) alpha-tocopherol acetate was formulated in the following vehicles: ethanol, isopropyl myristate, light mineral oil, 1% Klucel gel in ethanol, and 3% Klucel gel in ethanol (w/w). The receiver temperature was 37 degrees C. Samples from the receiver were collected at 2, 4, 6, 8, 12, 24, 30, 36, and 48 hours and analyzed by HPLC for concentrations of alpha-tocopherol acetate and alpha-tocopherol. The permeabilities of ATA through human cadaver skin were 1.0x10(-4), 1.1x10(-2), 1.4x10(-4), 2.1x10(-4), and 4.7x10(-4) cm/h for the ethanol solution, isopropyl myristate solution, light mineral oil solution, 1% Klucel gel, and 3% Klucel gel, respectively. The results show that the formulation had relatively minor effects on the permeability coefficients of ATA through cadaver skin in all cases except for the isopropyl myristate solution. PMID:15868062

  5. Heterogeneous catalyst for the production of acetic anhydride from methyl acetate

    DOEpatents

    Ramprasad, D.; Waller, F.J.

    1999-04-06

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

  6. Heterogeneous catalyst for the production of acetic anhydride from methyl acetate

    DOEpatents

    Ramprasad, Dorai (Allentown, PA); Waller, Francis Joseph (Allentown, PA)

    1999-01-01

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

  7. Transport through a Heterogeneous Alluvial Aquifer beneath an Agricultural Riparian Buffer

    NASA Astrophysics Data System (ADS)

    Johnson, R.; Mather, A. L.; Smith, E. A.; Green, C. T.

    2012-12-01

    Riparian buffer zones between agricultural fields and streams are intended to attenuate the groundwater transport of non-point-source pollutants. However, if the spatial variability in the alluvial aquifer structure provides pathways for rapid transit across the buffer, the effectiveness for mitigating transport of pollutants to the stream may be limited. The main objective of this work was to examine the effects of alluvial aquifer heterogeneity on groundwater transport beneath an agricultural riparian buffer. This was assessed first by performing a natural-gradient tracer experiment and characterizing the site heterogeneity through hydraulic conductivity profiling. Second, the field hydraulic conductivity data were used with a meandering geostatistical model to represent aquifer heterogeneity and a numerical groundwater model was constructed to simulate the tracer experiment. The tracer experiment showed that a portion of the injected plume (~10% of the total mass) moved at high velocity, while a significant fraction of the mass moved slowly and remained near the injection location. Both the tracer test and the numerical modeling indicate that transport velocities of a meter per day are likely to be present in localized regions throughout the riparian buffer. This highlights the dependence of solute residence time in the riparian zone, and therefore the concentrations arriving in rivers, on the local geological structure.

  8. Acetic acid recovery from a hybrid biological-hydrothermal treatment process of sewage sludge - a pilot plant study.

    PubMed

    Andrews, J; Dare, P; Estcourt, G; Gapes, D; Lei, R; McDonald, B; Wijaya, N

    2015-03-01

    A two-stage process consisting of anaerobic fermentation followed by sub-critical wet oxidation was used to generate acetic acid from sewage sludge at pilot scale. Volatile fatty acids, dominated by propionic acid, were produced over 4-6 days in the 2,000 L fermentation reactor, which also achieved 31% solids reduction. Approximately 96% of the carbon was retained in solution over the fermentation stage. Using a 200 L wet oxidation reactor operating in batch mode, the second stage achieved 98% volatile suspended solids (VSS) destruction and 67% total chemical oxygen demand (tCOD) destruction. Acetic acid produced in this stage was recalcitrant to further degradation and was retained in solution. The gross yield from VSS was 16% for acetic acid and 21% for volatile fatty acids across the process, higher than reported yields for wet oxidation alone. The pilot plant results showed that 72% of the incoming phosphorus was retained in the solids, 94% of the nitrogen became concentrated in solution and 41% of the carbon was converted to a soluble state, in a more degradable form. Acetic acid produced from the process has the potential to be used to offset ethanol requirements in biological nutrient removal plants. PMID:25768220

  9. Inhibition of enamel demineralization by buffering effect of S-PRG filler-containing dental sealant.

    PubMed

    Kaga, Masayuki; Kakuda, Shinichi; Ida, Yusuke; Toshima, Hirokazu; Hashimoto, Masanori; Endo, Kazuhiko; Sano, Hidehiko

    2014-02-01

    The buffering capacity and inhibitory effects on enamel demineralization of two commercially available dental sealants were evaluated in this study. The effects of filler particles were also examined. Disks of enamel and cured sealant materials of BeautiSealant (silica or S-PRG filler) or Teethmate F-1 were incubated in lactic acid solutions (pH 4.0) for 1-6 d. The pH changes and amounts of ions released in the solutions were assessed, and enamel surfaces were observed using a scanning electron microscope. The pH of the solution with BeautiSealant (S-PRG filler) was neutralized from pH 4.0 to pH 6.1 (after incubation for 1 d) and from pH 4.0 to pH 6.7 (after incubation for 6 d). In addition, no release of calcium ions was detected and the enamel surface was morphologically intact in scanning electron microscopy images. However, the pH of the solution with Teethmate F-1 remained below pH 4.0 during incubation from days 1 to 6. Calcium release was increased in solutions up to and after 6 d of incubation. Scanning electron microscopy images showed that the structures of hydroxyapatite rods were exposed at the specimen surfaces as a result of demineralization. Ions released from S-PRG filler-containing dental sealant rapidly buffered the lactic acid solution and inhibited enamel demineralization. PMID:24372898

  10. Biodegradable Blends of Cellulose Acetate and Starch: Production and Properties

    Microsoft Academic Search

    Jean M. Mayer; Glenn R. Elion; Charles M. Buchanan; Barbara K. Sullivan; Sheldon D. Pratt; David L. Kaplan

    1995-01-01

    Blends of cellulose acetate (2.5 degree of substitution) and starch were melt processed and evaluated for mechanical properties, biodegradability during composting, and marine and soil toxicity. Formulations containing, on a weight basis, 57% cellulose acetate (CA), 25% corn starch (St) and 19% propylene glycol (PG) had mechanical properties similar to polystyrene. Increasing plasticizer or starch content lowered tensile strength. Simulated

  11. Synthesis and characterization of cellulose acetate produced from recycled newspaper

    Microsoft Academic Search

    Guimes Rodrigues Filho; Douglas Santos Monteiro; Carla da Silva Meireles; Rosana Maria Nascimento de Assunção; Daniel Alves Cerqueira; Hernane Silva Barud; Sidney J. L. Ribeiro; Younes Messadeq

    2008-01-01

    In this work, the viability of recycling newspaper for producing cellulose acetate was tested. Newspaper recycling is extremely important not only for the environment preservation, but also from the economical point of view of aggregating value to this residue. Cellulose acetate was produced from a homogeneous acetylation, and then characterized by FTIR, DSC and TGA. Acetylation times were 48h for

  12. Transition-Metal-Catalyzed Carbonylation of Methyl Acetate.

    ERIC Educational Resources Information Center

    Polichnowski, S. W.

    1986-01-01

    Presents a study of the rhodium-catalyzed, ioding-promoted carbonylation of methyl acetate. This study provides an interesting contrast between the carbonylation of methyl acetate and the carbonylation of methanol when similar rhodium/iodine catalyst systems are used. (JN)

  13. Anaerobic thermophilic fermentation for acetic acid production from milk permeate.

    PubMed

    Talabardon, M; Schwitzguébel, J P; Péringer, P

    2000-01-01

    Fermentation of milk permeate to produce acetic acid under anaerobic thermophilic conditions (approximately 60 degrees C) was studied. Although none of the known thermophilic acetogenic bacteria can ferment lactose, it has been found that one strain can use galactose and two strains can use lactate. Moorella thermoautotrophica DSM 7417 and M. thermoacetica DSM 2955 were able to convert lactate to acetate at thermophilic temperatures with a yield of approximately 0.93 g g(-1). Among the strains screened for their abilities to produce acetate and lactate from lactose, Clostridium thermolacticum DSM 2910 was found precisely to produce large amounts of lactate and acetate. However, it also produced significant amounts of ethanol, CO2 and H2. The lactate yield was affected by cell growth. During the exponential phase, acetate, ethanol, CO2 and H2 were the main products of fermentation with an equimolar acetate/ethanol ratio, whereas during the stationary phase, only lactic acid was produced with a yield of 4 mol per mol lactose, thus reaching the maximal theoretical value. When this bacterium was co-cultured with M. thermoautotrophica, lactose was first converted mainly to lactic acid, then to acetic acid, with a zero residual lactic acid concentration and an overall yield of acetate around 80%. Under such conditions, only 13% of the fermented lactose was converted to ethanol by C. thermolacticum. PMID:10784299

  14. Original article Ethanol and acetic-acid tolerances

    E-print Network

    Paris-Sud XI, Université de

    Original article Ethanol and acetic-acid tolerances in Drosophila melanogaster: similar maternal) Summary - Ethanol and acetic-acid tolerances were studied in a cross between 2 geo- graphic races disappeared in the F2. Further investigations demonstrated that for ethanol tolerance, the large difference

  15. Liquid-liquid equilibria of the ternary systems water + acetic acid + ethyl acetate and water + acetic acid + isophorene (3,5,5-trimethyl-2-cyclohexen-1-one)

    SciTech Connect

    Colombo, A.; Battilana, P.; Ragaini, V.; Bianchi, C.L. [Milan Univ. (Italy). Dept. of Physical Chemistry and Electrochemistry] [Milan Univ. (Italy). Dept. of Physical Chemistry and Electrochemistry; Carvoli, G. [Chemial S.p.A., Cavaglia (Italy)] [Chemial S.p.A., Cavaglia (Italy)

    1999-01-01

    Liquid-liquid equilibria for the ternary systems water + acetic acid + ethyl acetate and water + acetic acid + isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) were measured over the temperature range (283 to 313) K. The results were used to estimate the interaction parameters between each of the three compounds of the systems studied for the NRTL and UNIQUAC models. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models; experimental data were successfully reproduced. The UNIQUAC model was the most accurate in correlating the overall equilibrium composition of the studied systems. Also the NRTL model satisfactorily predicted the equilibrium composition. Isophorone experimentally resulted in a better extraction capacity for acetic acid and in a lower miscibility with water.

  16. Potassium acetate and potassium lactate enhance the microbiological and physical properties of marinated catfish fillets.

    PubMed

    Kin, Sovann; Schilling, M Wes; Smith, Brian S; Silva, Juan L; Kim, Taejo; Pham, Alessandra J; Campano, Stephen G

    2011-05-01

    Sodium or potassium salts such as lactate and acetate can be used to inhibit the growth of spoilage bacteria and food-borne pathogens, and thereby prolong the shelf-life of refrigerated seafood. However, minimal information is available regarding the combined effects of potassium salts (acetate and lactate) with an agglomerated phosphate blend on the quality and safety of refrigerated catfish fillets. The objective of this study was to determine the microbiological and quality characteristics of marinated catfish fillets treated with organic acid salts. Catfish fillets were vacuum-tumbled with a brine solution with and without the added organic acid salts, at 10% over initial, raw weight prior to tray-packing and storage at 4 °C for 14 d. Fillets were evaluated for yields, color, pH, tenderness, consumer acceptability, and shelf-life. No differences (P > 0.05) existed among the treated and untreated fillets with regards to solution pick-up and pH, but all treated fillets increased (P < 0.05) cooking yields and Intl. Commission on Illumination (CIE) a* values, and decreased (P < 0.05) CIE L* and b* values in the catfish fillets when compared to the untreated fillets. The fillets treated with a combination of potassium acetate and potassium lactate had lower (P < 0.05) psychrotrophic plate counts and lower spoilage scores than the control treatments on days 7, 10, and 14. In addition, consumers preferred (P < 0.05) treated catfish fillets (fried) with respect to appearance, flavor, and overall acceptability over the negative control. In conclusion, the combination of potassium acetate and potassium lactate enhanced sensory quality and extended the shelf-life of refrigerated catfish fillets. PMID:22417369

  17. Interleaving buffer insertion and transistor sizing into a single optimization

    Microsoft Academic Search

    Yanbin Jiang; Sachin S. Sapatnekar; Cyrus Bamji; Juho Kim

    1998-01-01

    This work presents strategies to insert buffers in a circuit, combined with gate sizing, to achieve better power- delay and area-delay tradeoffs. The purpose of this work is to examine how combining a sizing algorithm with buffer insertion will help us achieve better area-delay or power-delay tradeoffs, and to determine where and when to insert buffers in a circuit. The

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

    Microsoft Academic Search

    W. Kindermann; J. Keul; G. Huber

    1977-01-01

    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.

  19. Enhancing soluble phosphorus removal within buffer strips using industrial by-products.

    PubMed

    Habibiandehkordi, Reza; Quinton, John N; Surridge, Ben W J

    2014-11-01

    Using industrial by-products (IBPs) in conjunction with buffer strips provides a potentially new strategy for enhancing soluble phosphorus (P) removal from agricultural runoff. Here, we investigate the feasibility of this approach by assessing the P sorption properties of IBPs at different solution-IBPs contact time (1-120 min) and solution pH (3, 5.5, 7.5), as well as possible adverse environmental effects including P desorption or heavy metal mobilisation from IBPs. Batch experiments were carried out on two widely available IBPs in the UK that demonstrated high P sorption capacity but different physicochemical characteristics, specifically ochre and Aluminium (Al) based water treatment residuals (Al-WTR). A series of kinetic sorption-desorption experiments alongside kinetic modelling were used to understand the rate and the mechanisms of P removal across a range of reaction times. The results of the kinetic experiments indicated that P was initially sorbed rapidly to both ochre and Al-WTR, followed by a second phase characterised by a slower sorption rate. The excellent fits of kinetic sorption data to a pseudo-second order model for both materials suggested surface chemisorption as the rate-controlling mechanism. Neither ochre nor Al-WTR released substantial quantities of either P or heavy metals into solution, suggesting that they could be applied to buffer strip soils at recommended rates (?30 g kg(-1) soil) without adverse environmental impact. Although the rate of P sorption by freshly-generated Al-WTR applied to buffer strips reduced following air-drying, this would not limit its practical application to buffer strips in the field if adequate contact time with runoff was provided. PMID:24928382

  20. Oxidation of indole-3-acetic acid and oxindole-3-acetic acid to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glucopyranoside in Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Nonhebel, H. M.; Bandurski, R. S.

    1984-01-01

    Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid --> Oxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid-glucoside.

  1. J. Chem. Soc., Perkin Trans. 2, 1997 821 Mechanism of the Beckmann rearrangement in sulfuric acid solution

    E-print Network

    Nguyen, Minh Tho

    a Beckmann mixture consists of a solution of acetic acid and acetic anhydride, saturated with gaseous hydrogen chloride, an oleum solution contains sulfuric acid and sulfur trioxide (H2SO4 SO3). An aqueous aqueous solutions of H2SO4, alicyclic oximes undergo hydrolysis rather than BR. In the industrial

  2. Measurement of the rates of oxindole-3-acetic acid turnover, and indole-3-acetic acid oxidation in Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Nonhebel, H. M.; Bandurski, R. S. (Principal Investigator)

    1986-01-01

    Oxindole-3-acetic acid is the principal catabolite of indole-3-acetic acid in Zea mays seedlings. In this paper measurements of the turnover of oxindole-3-acetic acid are presented and used to calculate the rate of indole-3-acetic acid oxidation. [3H]Oxindole-3-acetic acid was applied to the endosperm of Zea mays seedlings and allowed to equilibrate for 24 h before the start of the experiment. The subsequent decrease in its specific activity was used to calculate the turnover rate. The average half-life of oxindole-3-acetic acid in the shoots was found to be 30 h while that in the kernels had an average half-life of 35h. Using previously published values of the pool sizes of oxindole-3-acetic acid in shoots and kernels from seedlings of the same age and variety, and grown under the same conditions, the rate of indole-3-acetic acid oxidation was calculated to be 1.1 pmol plant-1 h-1 in the shoots and 7.1 pmol plant-1 h-1 in the kernels.

  3. Concentrated Flow through a Riparian Buffer: A Case Study

    NASA Astrophysics Data System (ADS)

    Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

    2004-05-01

    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 extend to which flow concentration affects buffer efficiency.

  4. Formation of ethyl acetate by Kluyveromyces marxianus on whey during aerobic batch cultivation at specific trace element limitation.

    PubMed

    Urit, Thanet; Stukert, Anton; Bley, Thomas; Löser, Christian

    2012-12-01

    Kluyveromyces marxianus is able to transform lactose into ethyl acetate as a bulk product which offers a chance for an economical reuse of whey-borne sugar. Ethyl acetate is highly volatile and allows its process-integrated recovery by stripping from the aerated bioreactor. Extensive formation of ethyl acetate by K. marxianus DSM 5422 required restriction of yeast growth by a lack of trace elements. Several aerobic batch processes were done in a 1-L stirred reactor using whey-borne culture medium supplemented with an individual trace element solution excluding Mn, Mo, Fe, Cu, or Zn for identifying the trace element(s) crucial for the observed ester synthesis. Only a lack of Fe, Cu, or Zn restricted yeast growth while exclusion of Mn and Mo did not exhibit any effect due to a higher amount of the latter in the used whey. Limitation of growth by Fe or Cu caused significant production of ethyl acetate while limitation by Zn resulted in formation of ethanol. A lack of Fe or Cu obviously makes the respiratory chain inefficient resulting in an increased mitochondrial NADH level followed by a reduced metabolic flux of acetyl-SCoA into the citrate cycle. Synthesis of ethyl acetate from acetyl-SCoA and ethanol by alcoholysis is thus interpreted as an overflow metabolism. PMID:22573271

  5. Highly Porous Regenerated Cellulose Fiber Mats via the Co-Forcespinning of Cellulose Acetate for Separator Applications

    NASA Astrophysics Data System (ADS)

    Castillo, Alejandro; Mao, Yuanbing

    2015-03-01

    Improvements in battery technology are necessary for the transition away from a fossil fuel based economy. An important bottle-neck in battery efficiency is the quality of the separator, which separates the cathode and anode to prevent a short-circuit while still allowing the ions in solution to flow as close to unabated as possible. In this work solutions of cellulose acetate, polyvinyldiflourine (pvdf), and polyvinylpyrrolidone (pvp) dissolved in a 2:1 v/v acetone/dimethylacetamide solvent mixture were Forcespun to create nonwoven fiber mats of nanoscale diameter. These mats were then soaked in a NaOH solution so as to both strip the pvp from the fiber as well as regenerate cellulose from its acetate derivative for the purpose of creating high surface area, nanoporous, hydrophilic, and ioniclly conductive cellulose/pvdf nonwoven mats for the purposes of testing their suitability as battery separators

  6. New cadmium-free buffer layers as heterojunction partners on Cu(In,Ga)(S,Se)2 thin film solar cells

    Microsoft Academic Search

    W. Eisele; A. Ennaoui; P. Schubert-Bischoff; M. Giersig; C. Pettenkofer; J. Krauser; M. Lux-Steiner; T. Riedle; N. Esser; S. Zweigart; F. Karg

    2000-01-01

    A Zn(Se,OH) buffer layer deposited by chemical bath process on Cu(In,Ga)(S,Se)2 (CIGSS) absorbers is investigated. Before deposition of the actual ZnSe layer, the absorber is immersed in a Zn-containing solution (Zn treatment). Transmission electron microscopy (TEM) pictures of the buffer layer exhibit two different areas: a dark structured layer containing small crystals of ZnSe and a bright amorphous layer, which

  7. Surface Treatments of Nb by Buffered Electropolishing

    SciTech Connect

    Wu, Andy T. [JLAB; Rimmer, Robert A. [JLAB; Ciovati, Gianluigi [JLAB; Manus, Robert L. [JLAb; Reece, Charles E. [JLAB; Williams, J. S. [JLAB; Eozénou, F. [CEA, Gif-sur-Yvette; Jin, S. [PKU/IHIP, Beijing; Lin, L. [PKU/IHIP, Beijing; Lu, X.Y. [PKU/IHIP, Beijing; Mammosser, John D. [JLAB; Wang, E. [BNL

    2009-11-01

    Buffered electropolishing (BEP) is a Nb surface treatment technique developed at Jefferson Lab1. Experimental results obtained from flat Nb samples show2-4 that BEP can produce a surface finish much smoother than that produced by the conventional electropolishing (EP), while Nb removal rate can be as high as 4.67 ?m/min. This new technique has been applied to the treatments of Nb SRF single cell cavity employing a vertical polishing system5 constructed at JLab as well as a horizontal polishing system at CEA Saclay. Preliminary results show that the accelerating gradient can reach 32 MV/m for a large grain cavity and 26.7 MV/m for a regular grain cavity. In this presentation, the latest progresses from the international collaboration between Peking University, CEA Saclay, and JLab on BEP will be summarized.

  8. Huge capacity optical packet switching and buffering.

    PubMed

    Shinada, Satoshi; Furukawa, Hideaki; Wada, Naoya

    2011-12-12

    We demonstrate 2.56 Tbit/s/port dual-polarization DWDM/DQPSK variable-length optical packet (20 Gbit/s × 64 wavelengths × 2 polarizations) switching and buffering by using a 2×2 optical packet switch (OPS) system. The optical data plane of the OPS system was constructed of multi-connected electro-optical switches and fiber delay lines. The accumulated polarization dependent loss of each optical path in the data plane was less than 5 dB. This low-polarization-dependence OPS system enabled us to handle DWDM/DQPSK optical packets (1.28 Tbit/s/port) with time-varying polarization after transmission through 100 km fiber in the field. PMID:22274050

  9. Natriuretic peptides buffer renin-dependent hypertension.

    PubMed

    Demerath, Theo; Staffel, Janina; Schreiber, Andrea; Valletta, Daniela; Schweda, Frank

    2014-06-15

    The renin-angiotensin-aldosterone system and cardiac natriuretic peptides [atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP)] are opposing control mechanisms for arterial blood pressure. Accordingly, an inverse relationship between plasma renin concentration (PRC) and ANP exists in most circumstances. However, PRC and ANP levels are both elevated in renovascular hypertension. Because ANP can directly suppress renin release, we used ANP knockout (ANP(-/-)) mice to investigate whether high ANP levels attenuate the increase in PRC in response to renal hypoperfusion, thus buffering renovascular hypertension. ANP(-/-) mice were hypertensive and had reduced PRC compared with that in wild-type ANP(+/+) mice under control conditions. Unilateral renal artery stenosis (2-kidney, 1-clip) for 1 wk induced similar increases in blood pressure and PRC in both genotypes. Unexpectedly, plasma BNP concentrations in ANP(-/-) mice significantly increased in response to two-kidney, one-clip treatment, potentially compensating for the lack of ANP. In fact, in mice lacking guanylyl cyclase A (GC-A(-/-) mice), which is the common receptor for both ANP and BNP, renovascular hypertension was markedly augmented compared with that in wild-type GC-A(+/+) mice. However, the higher blood pressure in GC-A(-/-) mice was not caused by disinhibition of the renin system because PRC and renal renin synthesis were significantly lower in GC-A(-/-) mice than in GC-A(+/+) mice. Thus, natriuretic peptides buffer renal vascular hypertension via renin-independent effects, such as vasorelaxation. The latter possibility is supported by experiments in isolated perfused mouse kidneys, in which physiological concentrations of ANP and BNP elicited renal vasodilatation and attenuated renal vasoconstriction in response to angiotensin II. PMID:24717731

  10. Pharmacokinetics and drug interactions of eslicarbazepine acetate.

    PubMed

    Bialer, Meir; Soares-da-Silva, Patricio

    2012-06-01

    Eslicarbazepine acetate (ESL) is a novel once-daily antiepileptic drug (AED) approved in Europe since 2009 that was found to be efficacious and well tolerated in a phase III clinical program in adult patients with partial onset seizures previously not controlled with treatment with one to three AEDs, including carbamazepine (CBZ). ESL shares with CBZ and oxcarbazepine (OXC) the dibenzazepine nucleus bearing the 5-carboxamide substitute, but is structurally different at the 10,11 position. This molecular variation results in differences in metabolism, preventing the formation of toxic epoxide metabolites such as carbamazepine-10,11-epoxide. Unlike OXC, which is metabolized to both eslicarbazepine and (R)-licarbazepine, ESL is extensively converted to eslicarbazepine. The systemic exposure to eslicarbazepine after ESL oral administration is approximately 94% of the parent dose, with minimal exposure to (R)-licarbazepine and OXC. After ESL oral administration, the effective half-life (t(1/2,eff) ) of eslicarbazepine was 20-24 h, which is approximately two times longer than its terminal half-life (t(1/2)). At clinically relevant doses (400-1,600 mg/day) ESL has linear pharmacokinetics (PK) with no effects of gender or moderate liver impairment. However, because eslicarbazepine is eliminated primarily (66%) by renal excretion, dose adjustment is recommended for patients with renal impairment. Eslicarbazepine clearance is induced by phenobarbital, phenytoin, and CBZ and it dose-dependently decreases plasma exposure of oral contraceptive and simvastatin. PMID:22612290

  11. Eslicarbazepine acetate for partial-onset seizures.

    PubMed

    Rauchenzauner, Markus; Luef, Gerhard

    2011-12-01

    Eslicarbazepine acetate (ESL), a new voltage-gated sodium channel blocker that is chemically related to carbamazepine and partially metabolized to oxcarbazepine, has attracted attention as results of previous Phase II and III studies demonstrated and confirmed efficacy and tolerability of ESL 800 and 1200 mg once daily as add-on therapy for adult patients with drug-resistant partial-onset seizures. In children, efficacy data point towards a dose-dependent decrease in seizure frequency and tolerability analyses showed a low incidence of mild drug-related adverse effects at 5 and 15 mg/kg/day. The most frequently reported adverse effects were dizziness, somnolence, headache, diplopia, nausea and vomiting. The convenience of once-daily dosing and a short/simple titration regimen in combination with a comparative efficacy and tolerability profile might promote ESL as a valid alternative to the current adjunctive antiepileptic drug therapy armamentarium for drug-resistant partial seizures in adults. Since clinical trials in children and adolescents on ESL efficacy and safety are ongoing and data already published are far from conclusive, the therapeutic value of ESL in this special population has to be established in the near future. PMID:22091592

  12. Micelles Protect and Concentrate Activated Acetic Acid

    NASA Astrophysics Data System (ADS)

    Todd, Zoe; House, C.

    2014-01-01

    As more and more exoplanets are discovered and the habitability of such planets is considered, one can turn to searching for the origin of life on Earth in order to better understand what makes a habitable planet. Activated acetic acid, or methyl thioacetate, has been proposed to be central to the origin of life on Earth, and also as an important energy currency molecule in early cellular evolution. We have investigated the hydrolysis of methyl thioacetate under various conditions. Its uncatalyzed rate of hydrolysis is about three orders of magnitude faster (K = 0.00663 s^-1; 100°C, pH 7.5, concentration = 0.33mM) than published rates for its catalyzed production making it unlikely to accumulate under prebiotic conditions. However, we also observed that methyl thioacetate was protected from hydrolysis when inside its own hydrophobic droplets. We found that methyl thioacetate protection from hydrolysis was also possible in droplets of hexane and in the membranes of nonanoic acid micelles. Thus, the hydrophobic regions of prebiotic micelles and early cell membranes could have offered a refuge for this energetic molecule increasing its lifetime in close proximity to the reactions for which it would be needed. Methyl thioacetate could thus be important for the origin of life on Earth and perhaps for better understanding the potential habitability of other planets.

  13. Emergency contraception: potential role of ulipristal acetate.

    PubMed

    Gemzell-Danielsson, Kristina; Meng, Chun-Xia

    2010-01-01

    Unintended pregnancy is a global reproductive health problem. Emergency contraception (EC) provides women with a safe means of preventing unwanted pregnancies after having unprotected intercourse. While 1.5 mg of levonorgestrel (LNG) as a single dose or in 2 doses with 12 hours apart is the currently gold standard EC regimen, a single dose of 30 mg ulipristal acetate (UPA) has recently been proposed for EC use up to 120 hours of unprotected intercourse with similar side effect profiles as LNG. The main mechanism of action of both LNG and UPA for EC is delaying or inhibiting ovulation. However, the 'window of effect' for LNG EC seems to be rather narrow, beginning after selection of the dominant follicular and ending when luteinizing hormone peak begins to rise, whereas UPA appears to have a direct inhibitory effect on follicular rupture which allows it to be also effective even when administered shortly before ovulation, a time period when use of LNG is no longer effective. These experimental findings are in line with results from a series of clinical trials conducted recently which demonstrate that UPA seems to have higher EC efficacy compared to LNG. This review summarizes some of the data available on UPA used after unprotected intercourse with the purpose to provide evidence that UPA, a new type of second-generation progesterone receptor modulator, represents a new evolutionary step in EC treatment. PMID:21072297

  14. PHA based denitrification: municipal wastewater vs. acetate.

    PubMed

    Krasnits, Eli; Beliavsky, Michael; Tarre, Sheldon; Green, Michal

    2013-03-01

    Denitrification of municipal wastewater based on bacterial storage polymers-Polyhydroxyalkanoates (PHA) - was investigated in biofilm sequencing batch reactors, as a part of a two sludge system for wastewater treatment and in comparison to acetate based synthetic wastewater. The results show that PHA based denitrification (PBD) of real wastewater can be a viable alternative, especially for wastewater with low COD/N ratio, without the need for external carbon source addition. High nitrate removal capacity of about 40-50 mg N/L with a low COD/N requirement of about 4-5, were observed. It was found that entrapped particulate organic matter contributed additional reducing power, on top of the storage materials, thus allowing for the high nitrate reduction capacity. Daily removal rates were similar to those of extensive treatment systems (0.24-0.31 gr N/L reactor*d). Large differences in storage yield and composition between biomass grown on synthetic and municipal wastewater were observed. PMID:23395755

  15. Polyvinyl acetate-based film coatings.

    PubMed

    Kolter, K; Dashevsky, A; Irfan, Muhamad; Bodmeier, R

    2013-12-01

    Polyvinyl acetate-based colloidal aqueous polymer dispersion Kollicoat(®) SR 30 D results in coatings characterized by moderate swelling behaviour, lipophilicity, pH-independent permeability for actives and high flexibility to withstand mechanical stress and is therefore used for controlled release coating. The colloidal aqueous polymer dispersion of Kollicoat(®) SR 30 D can be easily processed due to an optimal low minimum film forming temperature (MFT) of 18 °C without plasticizer addition and a thermal after-treatment (curing) of coated pellets. The drug release from Kollicoat(®) SR 30 D coated pellets was almost pH independent. Drug release could be easily adjusted by coating level or addition of soluble pore forming polymers. Physically stable Kollicoat(®) SR 30 D dispersions were obtained with the water-soluble polymers Kollidon(®) 30 and Kollicoat(®) IR up to 50% w/w. The addition of only 10% w/w triethyl citrate as plasticizer improved the flexibility of the films significantly and allowed compaction of the pellets. The drug release was almost independent of the compression force and the pellet content of the tablets. The inclusion of various tableting excipients slightly affected the drug release, primarily because of a different disintegration rate of the tablets. A combination of Kollicoat(®) SR 30 D and Kollicoat(®) IR with higher coating levels>10 mg/cm(2) is a relatively new alternative to OROS system which does not require drilling. PMID:24076229

  16. Analysis of three variables in sampling solutions used to assay bacteria of hands: type of solution, use of antiseptic neutralizers, and solution temperature.

    PubMed Central

    Larson, E L; Strom, M S; Evans, C A

    1980-01-01

    Tests were performed using the sterile bag technique to determine the effects of type of sampling solution, use of antiseptic neutralizers, and solution temperature on the detection and quantitation of bacteria on hands. Using paired hand cultures, three sampling solutions were compared: quarter-strength Ringer solution, a phosphate buffer containing Triton X-100, and the same buffer containing antiseptic neutralizers. The phosphate buffer containing Triton X-100 was significantly better than quarter-strength Ringer solution in mean bacterial yield; the neutralizer-containing sampling solution was slightly better than Triton X-100-containing solution, although differences were not significant at the P = 0.05 level. Temperature (6 or 23 degrees C) of the sampling solution showed no consistent effect on bacterial yield from hands tested with the fluid containing neutralizers. PMID:7012171

  17. 40 CFR 180.1258 - Acetic acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Acetic acid; exemption from the requirement...From Tolerances § 180.1258 Acetic acid; exemption from the requirement...residues of the biochemical pesticide acetic acid when used as a...

  18. 40 CFR 180.1258 - Acetic acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Acetic acid; exemption from the requirement...From Tolerances § 180.1258 Acetic acid; exemption from the requirement...residues of the biochemical pesticide acetic acid when used as a...

  19. Comparative shell buffering properties correlate with anoxia tolerance in freshwater turtles.

    PubMed

    Jackson, Donald C; Taylor, Sarah E; Asare, Vivian S; Villarnovo, Dania; Gall, Jonathan M; Reese, Scott A

    2007-02-01

    Freshwater turtles as a group are more resistant to anoxia than other vertebrates, but some species, such as painted turtles, for reasons not fully understood, can remain anoxic at winter temperatures far longer than others. Because buffering of lactic acid by the shell of the painted turtle is crucial to its long-term anoxic survival, we have tested the hypothesis that previously described differences in anoxia tolerance of five species of North American freshwater turtles may be explained at least in part by differences in their shell composition and buffering capacity. All species tested have large mineralized shells. Shell comparisons included 1) total shell CO2 concentration, 2) volume of titrated acid required to hold incubating shell powder at pH 7.0 for 3 h (an indication of buffer release from shell), and 3) lactate concentration of shell samples incubated to equilibrium in a standard lactate solution. For each measurement, the more anoxia-tolerant species (painted turtle, Chrysemys picta; snapping turtle, Chelydra serpentina) had higher values than the less anoxia-tolerant species (musk turtle, Sternotherus odoratus; map turtle, Graptemys geographica; red-eared slider, Trachemys scripta). We suggest that greater concentrations of accessible CO2 (as carbonate or bicarbonate) in the more tolerant species enable these species, when acidotic, to release more buffer into the extracellular fluid and to take up more lactic acid into their shells. We conclude that the interspecific differences in shell composition and buffering can contribute to, but cannot explain fully, the variations observed in anoxia tolerance among freshwater turtles. PMID:17008457

  20. Selective formation of organo, organo-aqueous, and hydro gel-like materials from partially hydrolysed poly(vinyl acetate)s based on different boron-containing crosslinkers.

    PubMed

    Angelova, L V; Leskes, M; Berrie, B H; Weiss, R G

    2015-06-17

    Viscoelastic, gel-like, polymeric dispersions (HVPDs) can be prepared by crosslinking polyols with borax or boric acid in water under alkaline conditions. Rheologically similar HVPDs have been prepared in organic liquids containing no water or hydroxylic groups through crosslinking partially or fully hydrolysed poly(vinyl acetate)s with trimethyl borate, boric acid, or borax. The organo-HVPDs are water-sensitive and rheoreversible on exposure to water. They were characterised rheologically and by solution and solid-state (11)B NMR spectroscopy. Spectroscopic analyses show the presence of mono- and di-diol crosslinks, as well as non-crosslinked boron species in HVPDs prepared with trimethyl borate or boric acid. The number of crosslinks in organo-HVPDs prepared with borax increased over the course of several days. Results from solution and solid-state (11)B NMR spectroscopy are comparable; no solid-like component was detectable. We demonstrate that hydro, organo, or organo-aqueous HVPDs can be obtained from partially hydrolysed poly(vinyl acetate)s by 'tuning' the structure of the boron-based crosslinker. PMID:26027551

  1. Developing suitable buffers to capture transport cycling behavior.

    PubMed

    Madsen, Thomas; Schipperijn, Jasper; Christiansen, Lars Breum; Nielsen, Thomas Sick; Troelsen, Jens

    2014-01-01

    The association between neighborhood built environment and cycling has received considerable attention in health literature over the last two decades, but different neighborhood definitions have been used and it is unclear which one is most appropriate. Administrative or fixed residential spatial units (e.g., home-buffer-based neighborhoods) are not necessarily representative for environmental exposure. An increased understanding of appropriate neighborhoods is needed. GPS cycling tracks from 78 participants for 7?days form the basis for the development and testing of different neighborhood buffers for transport cycling. The percentage of GPS points per square meter was used as indicator of the effectiveness of a series of different buffer types, including home-based network buffers, shortest route to city center buffers, and city center-directed ellipse-shaped buffers. The results show that GPS tracks can help us understand where people go and stay during the day, which can help us link built environment with cycling. Analysis showed that the further people live from the city center, the more elongated are their GPS tracks, and the better an ellipse-shaped directional buffer captured transport cycling behavior. In conclusion, we argue that in order to be able to link built environment factors with different forms of physical activity, we must study the most likely area people use. In this particular study, to capture transport cycling, with its relatively large radius of action, city center-directed ellipse-shaped buffers yielded better results than traditional home-based network buffer types. The ellipse-shaped buffer types could therefore be considered an alternative to more traditional buffers or administrative units in future studies of transport cycling behavior. PMID:24926478

  2. Computerized image analysis for acetic acid induced intraepithelial lesions

    NASA Astrophysics Data System (ADS)

    Li, Wenjing; Ferris, Daron G.; Lieberman, Rich W.

    2008-03-01

    Cervical Intraepithelial Neoplasia (CIN) exhibits certain morphologic features that can be identified during a visual inspection exam. Immature and dysphasic cervical squamous epithelium turns white after application of acetic acid during the exam. The whitening process occurs visually over several minutes and subjectively discriminates between dysphasic and normal tissue. Digital imaging technologies allow us to assist the physician analyzing the acetic acid induced lesions (acetowhite region) in a fully automatic way. This paper reports a study designed to measure multiple parameters of the acetowhitening process from two images captured with a digital colposcope. One image is captured before the acetic acid application, and the other is captured after the acetic acid application. The spatial change of the acetowhitening is extracted using color and texture information in the post acetic acid image; the temporal change is extracted from the intensity and color changes between the post acetic acid and pre acetic acid images with an automatic alignment. The imaging and data analysis system has been evaluated with a total of 99 human subjects and demonstrate its potential to screening underserved women where access to skilled colposcopists is limited.

  3. Crystal structure of a mixed solvated form of amoxapine acetate

    PubMed Central

    Bhardwaj, Rajni M.; Raval, Vishal; Oswald, Iain D. H.; Florence, Alastair J.

    2015-01-01

    The mixed solvated salt 4-(2-chloro­dibenzo[b,f][1,4]oxazepin-11-yl)piperazin-1-ium acetate–acetic acid–cyclo­hexane (2/2/1), C17H17ClN3O+·C2H3O2 ?·C2H4O2·0.5C6H12, crystallizes with one mol­ecule of protonated amoxapine (AXPN), an acetate anion and a mol­ecule of acetic acid together with half a mol­ecule of cyclo­hexane. In the centrosymmetric crystal, both enanti­omers of the protonated AXPN mol­ecule stack alternatively along [001]. Acetate anions connect the AXPN cations through N—H?O hydrogen bonding in the [010] direction, creating a sheet lying parallel to (100). The acetic acid mol­ecules are linked to the acetate anions via O—H?O hydrogen bonds within the sheets. Within the sheets there are also a number of C—H?O hydrogen bonds present. The cyclo­hexane solvent mol­ecules occupy the space between the sheets. PMID:25878802

  4. Perspectives for the biotechnological production of ethyl acetate by yeasts.

    PubMed

    Löser, Christian; Urit, Thanet; Bley, Thomas

    2014-06-01

    Ethyl acetate is an environmentally friendly solvent with many industrial applications. The production of ethyl acetate currently proceeds by energy-intensive petrochemical processes which are based on natural gas and crude oil without exception. Microbial synthesis of ethyl acetate could become an interesting alternative. The formation of esters as aroma compounds in food has been repeatedly reviewed, but a survey which deals with microbial synthesis of ethyl acetate as a bulk product is missing. The ability of yeasts for producing larger amounts of this ester is known for a long time. In the past, this potential was mainly of scientific interest, but in the future, it could be applied to large-scale ester production from renewable raw materials. Pichia anomala, Candida utilis, and Kluyveromyces marxianus are yeasts which convert sugar into ethyl acetate with a high yield where the latter is the most promising one. Special attention was paid to the mechanism of ester synthesis including regulatory aspects and to the maximum and expectable yield. Synthesis of much ethyl acetate requires oxygen which is usually supplied by aeration. Ethyl acetate is highly volatile so that aeration results in its phase transfer and stripping. This stripping process cannot be avoided but requires adequate handling during experimentation and offers a chance for a cost-efficient process-integrated recovery of the synthesized ester. PMID:24788328

  5. Recovering/concentrating of hemicellulosic sugars and acetic acid by nanofiltration and reverse osmosis from prehydrolysis liquor of kraft based hardwood dissolving pulp process.

    PubMed

    Ahsan, Laboni; Jahan, M Sarwar; Ni, Yonghao

    2014-03-01

    This work investigated the feasibility of recovering and concentrating sugars and acetic acid (HAc) from prehydrolysis liquor (PHL) of the kraft-based dissolving pulp process prior to fermentation of hemicellulosic sugars, by the combination of activated carbon adsorption, nanofiltration (NF) and reverse osmosis (RO) processes. To reduce the fouling PHL was subjected to adsorption on activated carbon, then the treated PHL (TPHL) passed through a nanofiltration (NF DK) membrane to retain the sugars, and the permeate of acetic acid rich solution was passed through a reverse osmosis membrane (RO SG). It was found that for NF process sugars were concentrated from 48 to 227g/L at a volume reduction factor (VRF) of 5 while 80 to 90% of acetic acid was permeated. For the reverse osmosis process, 68% of acetic acid retention was achieved at pH 4.3 and 500 psi pressure and the HAc concentration increased from 10 to 50g/L. PMID:24434701

  6. SAGA complex components and acetate repression in Aspergillus nidulans.

    PubMed

    Georgakopoulos, Paraskevi; Lockington, Robin A; Kelly, Joan M

    2012-11-01

    Alongside the well-established carbon catabolite repression by glucose and other sugars, acetate causes repression in Aspergillus nidulans. Mutations in creA, encoding the transcriptional repressor involved in glucose repression, also affect acetate repression, but mutations in creB or creC, encoding components of a deubiquitination system, do not. To understand the effects of acetate, we used a mutational screen that was similar to screens that uncovered mutations in creA, creB, and creC, except that glucose was replaced by acetate to identify mutations that were affected for repression by acetate but not by glucose. We uncovered mutations in acdX, homologous to the yeast SAGA component gene SPT8, which in growth tests showed derepression for acetate repression but not for glucose repression. We also made mutations in sptC, homologous to the yeast SAGA component gene SPT3, which showed a similar phenotype. We found that acetate repression is complex, and analysis of facA mutations (lacking acetyl CoA synthetase) indicates that acetate metabolism is required for repression of some systems (proline metabolism) but not for others (acetamide metabolism). Although plate tests indicated that acdX- and sptC-null mutations led to derepressed alcohol dehydrogenase activity, reverse-transcription quantitative real-time polymerase chain reaction showed no derepression of alcA or aldA but rather elevated induced levels. Our results indicate that acetate repression is due to repression via CreA together with metabolic changes rather than due to an independent regulatory control mechanism. PMID:23173087

  7. Clostridiumm ljungdahlii, an anaerobic ethanol and acetate producing microorganism

    DOEpatents

    Gaddy, J.L.; Clausen, E.C.

    1992-12-22

    A newly discovered microorganism was isolated in a biologically pure culture and designated Clostridium ljungdahlii, having the identifying characteristics of ATCC No. 49587. Cultured in an aqueous nutrient medium under anaerobic conditions, this microorganism is capable of producing ethanol and acetate from CO and H[sub 2]O and/or CO[sub 2] and H[sub 2] in synthesis gas. Under optimal growth conditions, the microorganism produces acetate in preference to ethanol. Conversely, under non-growth conditions, ethanol production is favored over acetate. 3 figs.

  8. Performance of slotted ALOHA satellite channels with finite buffer

    Microsoft Academic Search

    D. V. Ramana; V. V. S. Sarma

    1982-01-01

    The behavior of the slotted ALOHA satellite channel with a finite buffer at each of the user terminals is studied. Approximate relationships between the queuing delay, overflow probabilities and buffer size are derived as functions of the system input parameters (i.e. the number of users, the traffic intensity, the transmission and retransmission probabilities) for two cases found in the literature:

  9. The effect of systemic errors on optimal project buffers

    Microsoft Academic Search

    Dan Trietsch

    2005-01-01

    Existing mathematical models for setting buffers for time or cost in project management assume that project activities are statistically independent. This leads to a highly counterintuitive and damaging conclusion that project buffers should become relatively negligible for projects with long chains of activities. We present a model that considers the statistical dependence between activities caused by estimation bias. We show

  10. Influence of buffer on resonance frequency of thermoacoustic engine

    Microsoft Academic Search

    G. B Chen; J. P Jiang; J. L Shi; T. Jin; K. Tang; Y. L Jiang; N. Jiang; Y. H Huang

    2002-01-01

    Frequency matching is of great importance to a thermoacoustically driven pulse tube refrigeration system. To compute the resonance frequency of thermoacoustic engines, the fluid impedance method is introduced. The calculations of the thermoacoustic engines with different arrangements of buffer have been carried out. The influence of the buffer arrangements and the volume on the resonance frequency as well as the

  11. Cable Modem Buffer Management in DOCSIS Jim Martin,

    E-print Network

    Martin, Jim

    Cable Modem Buffer Management in DOCSIS Networks Jim Martin, James Westall School of Computing queue located in the cable modem. The strategy must contend with conflicting goals: large buffers might) amount of data. However, the upstream data rate available to a cable modem varies with the number

  12. CS 429H, Spring 2014 Lab 5: The Buffer Bomb

    E-print Network

    Witchel, Emmett

    CS 429H, Spring 2014 Lab 5: The Buffer Bomb Assigned: March 6, 2014, Due: March 20, 2014 convention it wants, so long as it's consistent. Hand Out Instructions You can obtain your buffer bomb bomb program you will attack. makecookie: Generates a "cookie" based on your userid. hex2raw: A utility

  13. Current isolating epitaxial buffer layers for high voltage photodiode array

    DOEpatents

    Morse, Jeffrey D. (Martinez, CA); Cooper, Gregory A. (Pleasant Hill, CA)

    2002-01-01

    An array of photodiodes in series on a common semi-insulating substrate has a non-conductive buffer layer between the photodiodes and the semi-insulating substrate. The buffer layer reduces current injection leakage between the photodiodes of the array and allows optical energy to be converted to high voltage electrical energy.

  14. Buffer waveguides for flow measurement in hot fluids

    Microsoft Academic Search

    Yi Liu; Lawrence C. Lynnworth; Maurits A. Zimmerman

    1998-01-01

    To obtain reliable ultrasonic flow measurements in the 200–300 C range continuously, with possible excursions to 450 C. buffer waveguides can be used to separate the piezoelement from the hot fluid. It is important that the buffer waveguides do not corrupt the signals. Until recently, this goal has been elusive because of dispersion, multipaths. mode conversion and beam spread (diffraction

  15. Fifteenmile Creek Riparian Buffers Project, Annual Report 2002-2003

    Microsoft Academic Search

    Graves; Ron

    2004-01-01

    This project implements riparian buffer systems in the Mid-Columbia, addressing limiting factors identified in the Fifteenmile Subbasin Summary, June 30, 2000. The project is providing the technical planning support needed to implement at least 36 riparian buffer system contracts on approximately 872 acres covering an estimated 40 miles of anadromous fish streams over a three year period. During this second

  16. Modeling of riparian vegetated buffer strip width and placement

    Microsoft Academic Search

    Young-Fa Lin; Chao-Yuan Lin; Wen-Chieh Chou; Wen-Tzu Lin; Jing-Shyan Tsai; Cho-Fu Wu

    2004-01-01

    This study addressed the suitable width for riparian vegetated buffer strips (RVBS) using topographic analyses, attenuation curves, and an index model. The Chi Chia Wang Stream is susceptible to pollution because of highly saturated hydraulic conductivity and excessive fertilizer use in the nearby cultivated lands. The buffer strip widths calculated from a potassium attenuation curve in the vegetable plot were

  17. Wasco Riparian Buffer Project, Annual Report 2003-2004

    Microsoft Academic Search

    Graves; Ron

    2003-01-01

    This project implements riparian buffer systems in the Mid-Columbia, addressing limiting factors identified in the Deschutes River Sub-basin Summary, March 2, 2001. This project is providing the technical planning support needed to implement at least 20 riparian buffer system contracts on approximately 800 acres covering an estimated 36 miles of anadromous fish streams. During this second year of implementation, 17

  18. Vegetated buffer management practice to improve surface water quality

    Microsoft Academic Search

    M. Zhang; X. Zhang; X. Liu

    2007-01-01

    Vegetated buffer best management practices (BMPs) installed in agricultural landscapes have been suggested as promising candidate tactics to reduce erosion and offsite transportation of agrochemicals. A wide range of vegetated buffer management practices have been installed in many areas to reduce agrochemical loss from applied fields, to filter sediments from tailwaters, and to deter their transportation to water bodies. This

  19. A First Step Towards Automated Detection of Buffer Overrun Vulnerabilities

    Microsoft Academic Search

    David Wagner; Jeffrey S. Foster; Eric A. Brewer; Alexander Aiken

    2000-01-01

    We describe a new technique for finding potential buffer overrun vulnerabilities in security-critical C code. The k ey to success is to use static analysis: we formulate detec- tion of buffer overruns as an integer range analysis prob- lem. One major advantage of static analysis is that secu- rity bugs can be eliminated before code is deployed. We have implemented

  20. Part III: Routers with very small buffers Mihaela Enachescu

    E-print Network

    Ganjali, Yashar

    Part III: Routers with very small buffers Mihaela Enachescu Department of Computer Science Stanford Roughgarden Department of Computer Science Stanford University tim@cs.stanford.edu ABSTRACT Internet routers. Unfortunately, a widely used rule-of-thumb says we need a bandwidth-delay product of buffering at each router so