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Sample records for acetate buffer medium

  1. Simultaneous analysis of several antiretroviral nucleosides in rat-plasma by high-performance liquid chromatography with UV using acetic acid/hydroxylamine buffer Test of this new volatile medium-pH for HPLC-ESI-MS/MS.

    PubMed

    Bezy, Vincent; Morin, Philippe; Couerbe, Philippe; Leleu, Ghislaine; Agrofoglio, Luigi

    2005-07-25

    Zalcitabine (ddC), lamivudine (3TC), didanosine (ddI), stavudine (d4T), carbovir (CBV), zidovudine (AZT), tenofovir (PMPA) and its administrated form (tenofovir diisoproxyl fumarate, TDF), are nucleosides currently approved in HIV therapy. To facilitate pharmacokinetics studies, a specific reversed-phase high-performance liquid chromatography (HPLC) method was developed for their analysis in rat plasma. The method involved a quantitative recovery of these drugs from rat plasma by solid-phase extraction on Oasis HLB Waters cartridges followed by optimised HPLC separation on an Atlantis dC18 column with acetic acid-hydroxylamine buffer (ionic strength 5mM, pH 7)-acetonitrile elution gradient. Quantitation was performed by HPLC/UV at 260 nm. Linear calibration curves were obtained within a 30-10,000 ng/mL plasma concentration range. Correlation coefficients (r2) greater than 0.992 were obtained by least-squares regression and limits of quantification were in 30-90 ng/mL concentration range. Quantitative parameters (accuracy, intra-day repeatability and inter-day reproducibility) yielded satisfactory results. Finally, a new buffer, obtained with acetic acid and hydroxylamine, has been tested in HPLC/ESI-MS/MS and appears to be an efficient volatile buffer in the medium 5-7 pH range. Indeed, at pH 7 and low ionic strength (5 mM), its buffer capacity is one hundred times higher to that obtained for the usual acetic acid/ammonia buffer.

  2. Tested Demonstrations: Buffer Capacity of Various Acetic Acid-Sodium Acetate Systems: A Lecture Experiment.

    ERIC Educational Resources Information Center

    Donahue, Craig J.; Panek, Mary G.

    1985-01-01

    Background information and procedures are provided for a lecture experiment which uses indicators to illustrate the concept of differing buffer capacities by titrating acetic acid/sodium acetate buffers with 1.0 molar hydrochloric acid and 1.0 molar sodium hydroxide. A table with data used to plot the titration curve is included. (JN)

  3. The Effects of Acetate Buffer Concentration on Lysozyme Solubility

    NASA Technical Reports Server (NTRS)

    Forsythe, Elizabeth L.; Pusey, Marc L.

    1996-01-01

    The micro-solubility column technique was employed to systematically investigate the effects of buffer concentration on tetragonal lysozyme solubility. While keeping the NaCl concentrations constant at 2%, 3%, 4%, 5% and 7%, and the pH at 4.0, we have studied the solubility of tetragonal lysozyme over an acetate buffer concentration range of 0.01M to 0.5M as a function of temperature. The lysozyme solubility decreased with increasing acetate concentration from 0.01M to 0.1M. This decrease may simply be due to the net increase in solvent ionic strength. Increasing the acetate concentration beyond 0.1M resulted in an increase in the lysozyme solubility, which reached a peak at - 0.3M acetate concentration. This increase was believed to be due to the increased binding of acetate to the anionic binding sites of lysozyme, preventing their occupation by chloride. In keeping with the previously observed reversal of the Hoffmeister series for effectiveness of anions in crystallizing lysozyme, acetate would be a less effective precipitant than chloride. Further increasing the acetate concentration beyond 0.3M resulted in a subsequent gradual decrease in the lysozyme solubility at all NaCl concentrations.

  4. Application of acetate buffer in pH adjustment of sorghum mash and its influence on fuel ethanol fermentation.

    PubMed

    Zhao, Renyong; Bean, Scott R; Crozier-Dodson, Beth Ann; Fung, Daniel Y C; Wang, Donghai

    2009-01-01

    A 2 M sodium acetate buffer at pH 4.2 was tried to simplify the step of pH adjustment in a laboratory dry-grind procedure. Ethanol yields or conversion efficiencies of 18 sorghum hybrids improved significantly with 2.0-5.9% (3.9% on average) of relative increases when the method of pH adjustment changed from traditional HCl to the acetate buffer. Ethanol yields obtained using the two methods were highly correlated (R (2) = 0.96, P < 0.0001), indicating that the acetate buffer did not influence resolution of the procedure to differentiate sorghum hybrids varying in fermentation quality. Acetate retarded the growth of Saccharomyces cerevisiae, but did not affect the overall fermentation rate. With 41-47 mM of undissociated acetic acid in mash of a sorghum hybrid at pH 4.7, rates of glucose consumption and ethanol production were inhibited during exponential phase but promoted during stationary phase. The maximum growth rate constants (mu(max)) were 0.42 and 0.32 h(-1) for cells grown in mashes with pH adjusted by HCl and the acetate buffer, respectively. Viable cell counts of yeast in mashes with pH adjusted by the acetate buffer were 36% lower than those in mashes adjusted by HCl during stationary phase. Coupled to a 5.3% relative increase in ethanol, a 43.6% relative decrease in glycerol was observed, when the acetate buffer was substituted for HCl. Acetate helped to transfer glucose to ethanol more efficiently. The strain tested did not use acetic acid as carbon source. It was suggested that decreased levels of ATP under acetate stress stimulate glycolysis to ethanol formation, increasing its yield at the expense of biomass and glycerol production.

  5. 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.

  6. 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 ...

  7. 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.

  8. Zymomonas with improved ethanol production in medium containing concentrated sugars and acetate

    SciTech Connect

    Caimi, Perry G.; Chou, Yat-Chen; Franden, Mary Ann; Knoke, Kyle; Tao, Luan; Viitanen, Paul V.; Zhang, Min; Zhang, Yuying

    2010-09-28

    Through screening of a Zymomonas mutant library the himA gene was found to be involved in the inhibitory effect of acetate on Zymomonas performance. Xylose-utilizing Zymomonas further engineered to reduce activity of the himA gene were found to have increased ethanol production in comparison to a parental strain, when cultured in medium comprising xylose and acetate.

  9. Graphene ultrathin film electrode for detection of lead ions in acetate buffer solution.

    PubMed

    Wang, Zhaomeng; Liu, Erjia

    2013-01-15

    Few-layer graphene ultrathin films were synthesized via solid-state carbon diffusion from amorphous carbon (a-C) thin layers sputtering coated on Si substrates with or without a SiO(2) layer, which an a-C layer was covered by a nickel (Ni) layer as a catalyst. When the Ni/a-C bilayer coated samples were heated at 1000°C the carbon (C) atoms from the a-C layers diffused into the top Ni layers to form a C rich surface. Upon rapid cooling, the C atoms accumulated on the surface of the Ni layers and formed graphene ultrathin films through nucleation and growth processes. The formation of graphene ultrathin films was confirmed by Raman spectroscopy, high resolution transmission electron microscopy (HR-TEM), electron diffraction, field-emission scanning electron microscopy (FE-SEM) and 4-point probe. The synthesized graphene ultrathin films were used as working electrodes for detection of trace heavy metal ions (Pb(2+), as low as 7 nM) in acetate buffer solutions (pH 5.3) using square wave anodic stripping voltammetry (SWASV). The effects of substrate surface condition and Ni layer thickness on the structure and electrochemical properties of graphene ultrathin film electrodes were investigated in detail. Compared to conventional diamond-like carbon (DLC) electrodes, the graphene electrodes developed in this study had better repeatability, higher sensitivity and higher resistance to passivation caused by surface active species.

  10. Graphene ultrathin film electrode for detection of lead ions in acetate buffer solution.

    PubMed

    Wang, Zhaomeng; Liu, Erjia

    2013-01-15

    Few-layer graphene ultrathin films were synthesized via solid-state carbon diffusion from amorphous carbon (a-C) thin layers sputtering coated on Si substrates with or without a SiO(2) layer, which an a-C layer was covered by a nickel (Ni) layer as a catalyst. When the Ni/a-C bilayer coated samples were heated at 1000°C the carbon (C) atoms from the a-C layers diffused into the top Ni layers to form a C rich surface. Upon rapid cooling, the C atoms accumulated on the surface of the Ni layers and formed graphene ultrathin films through nucleation and growth processes. The formation of graphene ultrathin films was confirmed by Raman spectroscopy, high resolution transmission electron microscopy (HR-TEM), electron diffraction, field-emission scanning electron microscopy (FE-SEM) and 4-point probe. The synthesized graphene ultrathin films were used as working electrodes for detection of trace heavy metal ions (Pb(2+), as low as 7 nM) in acetate buffer solutions (pH 5.3) using square wave anodic stripping voltammetry (SWASV). The effects of substrate surface condition and Ni layer thickness on the structure and electrochemical properties of graphene ultrathin film electrodes were investigated in detail. Compared to conventional diamond-like carbon (DLC) electrodes, the graphene electrodes developed in this study had better repeatability, higher sensitivity and higher resistance to passivation caused by surface active species. PMID:23200357

  11. Pseudomonas aeruginosa produces phosphatidyltris(hydroxymethyl)aminomethane and derivatives when grown in Tris-buffered medium.

    PubMed

    Abbes, Imen; Rihouey, Christophe; Hardouin, Julie; Dé, Emmanuelle; Jouenne, Thierry; Alexandre, Stéphane

    2016-08-01

    For optimal growth of a microorganism, the pH of the culture medium should be set at an optimum value. For that reason, growth media require buffering agents. We show in this study that, when grown in a medium supplemented with tris(hydroxymethyl)aminomethane (Tris), Pseudomonas aeruginosa is able to use this organic compound to produce new phospholipids. We thus pointed out that phosphatidyltris(hydroxymethyl)aminomethane as well as diphosphatidyltris(hydroxymethyl)aminomethane was detected in membrane lipid extracts of bacteria grown in Tris-buffered medium. Moreover, the amounts of lysoglycerophospholipids in the lipidome of P. aeruginosa grown in Tris-buffered medium increased leading to the presence of lysophosphatidylglycerol and lysophosphatidyltris(hydroxymethyl)aminomethane as well as other lysophospholipid derivatives. Finally, we investigated the effect of the presence of these exogenous phospholipids on the susceptibility of P. aeruginosa to some antibiotics. We observed a decrease of the minimal inhibitory concentrations of different antibiotic families, i.e., fluoroquinolones, aminoglycosides, ß-lactams and polymyxins, proving the importance of the buffer choice for growth medium and its impact on the lipidome. PMID:27126915

  12. Aniline blue-containing buffered charcoal-yeast extract medium for presumptive identification of Legionella species

    SciTech Connect

    Holmes, R.L.

    1982-04-01

    By utilizing buffered charcoal-yeast extract medium containing 0.01% aniline blue in conjunction with a long-wave UV light, the differentiation of five species of Legionella was facilitated. L. pneumophila, when grown on this medium, did not absorb the aniline blue dye; however, L. micdadei, L. dumoffii, L. bozemanii, and L. gormanii absorbed the dye in varying amounts and produced colonies of various shades of blue.

  13. Quantitative Screening of Agrochemical Residues in Fruits and Vegetables by Buffered Ethyl Acetate Extraction and LC-MS/MS Analysis.

    PubMed

    Jadhav, Manjusha R; Oulkar, Dasharath P; Shabeer T P, Ahammed; Banerjee, Kaushik

    2015-05-13

    A buffered ethyl acetate extraction method is proposed for the simultaneous analysis of 296 agrochemicals in a wide range of fruit and vegetable matrices by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The optimized quantity of acetate buffer (1% acetic acid + 0.5 g of sodium acetate per 10 g of sample) adjusted the pH of each test matrix to 5-6, which in turn significantly improved recoveries of acidic and basic compounds. The role of diethylene glycol (used in the evaporation step) on signal suppression of certain compounds was evaluated, and its quantity was optimized to minimize such an effect. The method was validated in grape, mango, drumstick, bitter gourd, capsicum, curry leaf, and okra as per the DG-SANCO/12571/2013 guidelines. Recoveries in the fortification range of 1-40 μg/kg were within 70-120% with associated relative standard deviations below 20% for most of the compounds. The method has potential for regulatory and commercial applications with a generic approach. PMID:25639652

  14. Zymomonas with improved ethanol production in medium containing concentrated sugars and acetate

    SciTech Connect

    Caimi, Perry G.; Chou, Yat-Chen; Franden, Mary Ann; Knoke, Kyle; Tao, Luan; Viitanen, Paul V.; Zhang, Min; Zhang, Yuying

    2011-03-01

    Through screening of a Zymomonas mutant library the himA gene was found to be involved in the inhibitory effect of acetate on Zymomonas performance. Xylose-utilizing Zymomonas strains further engineered to reduce activity of the himA gene were found to have increased ethanol production in comparison to a parental strain, when cultured in mixed-sugars medium comprising xylose, and, in particular, in the presence of acetate.

  15. Effects of sodium acetate buffer on chitosan sponge properties and in vivo degradation in a rat intramuscular model.

    PubMed

    Parker, Ashley Cox; Smith, James Keaton; Reves, Benjamin; Jennings, Jessica Amber; Bumgardner, Joel D; Haggard, Warren O

    2015-02-01

    Chitosan sponges were developed for adjunctive local antibiotic delivery to reduce bacteria in wounds. There is a need to increase sponge degradation for rapid clearance from the wound site during initial wound care. This work examined the effect of using 0.25 M sodium acetate buffers, at pH 4.6 or 5.6, to fabricate sponges with an amorphous chitosan polymer structure. Sponges were evaluated for their crystallinity, thermal, spectroscopic, and morphological properties, in addition to in vitro degradation, and cytocompatibility analysis using normal human dermal fibroblasts. In vivo degradation and biocompatibility were also examined after 4 and 10 days in rat intramuscular tissues. Both buffered chitosan sponge variations exhibited decreases in crystallinity and thermal decomposition temperatures, and increases in surface roughness, which resulted in over 40% increases in degradation over 10 days in vitro compared to the neutral sponges. There were no significant differences between sponges during in vivo degradation over 10 days with respect to histomorphometric analysis of the recovered sponges. These results demonstrated that the acetate buffer did change characteristic chitosan sponge material properties, and increasing the in vivo sponge degradation rate will require balancing material characteristics and processing.

  16. Acid-base and respiratory properties of a buffered bovine erythrocyte perfusion medium.

    PubMed

    Lindinger, M I; Heigenhauser, G J; Jones, N L

    1986-05-01

    Current research in organ physiology often utilizes in situ or isolated perfused tissues. We have characterized a perfusion medium associated with excellent performance characteristics in perfused mammalian skeletal muscle. The perfusion medium consisting of Krebs-Henseleit buffer, bovine serum albumin, and fresh bovine erythrocytes was studied with respect to its gas-carrying relationships and its response to manipulation of acid-base state. Equilibration of the perfusion medium at base excess of -10, -5, 0, 5, and 10 mmol X L-1 to humidified gas mixtures varying in their CO2 and O2 content was followed by measurements of perfusate hematocrit, hemoglobin concentration, pH, Pco2, Cco2, Po2, and percent oxygen saturation. The oxygen dissociation curve was similar to that of mammalian bloods, having a P50 of 32 Torr (1 Torr = 133.3 Pa), Hill's constant n of 2.87 +/- 0.15, and a Bohr factor of -0.47, showing the typical Bohr shifts with respect to CO2 and pH. The oxygen capacity was calculated to be 190 mL X L-1 blood. The carbon dioxide dissociation curve was also similar to that of mammalian blood. The in vitro nonbicarbonate buffer capacity (delta [HCO3-] X delta pH-1) at zero base excess was -24.6 and -29.9 mmol X L-1 X pH-1 for the perfusate and buffer, respectively. The effects of reduced oxygen saturation on base excess and pH of the medium were quantified. The data were used to construct an acid-base alignment diagram for the medium, which may be used to quantify the flux of nonvolatile acid or base added to the venous effluent during tissue perfusions.

  17. 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.; Van Driessche, I.

    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.

  18. A new medium containing mupirocin, acetic acid, and norfloxacin for the selective cultivation of bifidobacteria.

    PubMed

    Vlková, Eva; Salmonová, Hana; Bunešová, Věra; Geigerová, Martina; Rada, Vojtěch; Musilová, Šárka

    2015-08-01

    Various culture media have been proposed for the isolation and selective enumeration of bifidobacteria. Mupirocin is widely used as a selective factor along with glacial acetic acid. TOS (transgalactosylated oligosaccharides) medium supplemented with mupirocin is recommended by the International Dairy Federation for the detection of bifidobacteria in fermented milk products. Mupirocin media with acetic acid are also reliable for intestinal samples in which bifidobacteria predominate. However, for complex samples containing more diverse microbiota, the selectivity of mupirocin media is limited. Resistance to mupirocin has been demonstrated by many anaerobic bacteria, especially clostridia. The objective was to identify an antibiotic that inhibits the growth of clostridia and allows the growth of bifidobacteria, and to use the identified substance to develop a selective cultivation medium for bifidobacteria. The susceptibility of bifidobacteria and clostridia to 12 antibiotics was tested on agar using the disk diffusion method. Only norfloxacin inhibited the growth of clostridia and did not affect the growth of bifidobacteria. Using both pure cultures and faecal samples from infants, adults, calves, lambs, and piglets, the optimal concentration of norfloxacin in solid cultivation media was determined to be 200 mg/L. Our results showed that solid medium containing norfloxacin (200 mg/L) in combination with mupirocin (100 mg/L) and glacial acetic acid (1 mL/L) is suitable for the enumeration and isolation of bifidobacteria from faecal samples of different origins.

  19. A new medium containing mupirocin, acetic acid, and norfloxacin for the selective cultivation of bifidobacteria.

    PubMed

    Vlková, Eva; Salmonová, Hana; Bunešová, Věra; Geigerová, Martina; Rada, Vojtěch; Musilová, Šárka

    2015-08-01

    Various culture media have been proposed for the isolation and selective enumeration of bifidobacteria. Mupirocin is widely used as a selective factor along with glacial acetic acid. TOS (transgalactosylated oligosaccharides) medium supplemented with mupirocin is recommended by the International Dairy Federation for the detection of bifidobacteria in fermented milk products. Mupirocin media with acetic acid are also reliable for intestinal samples in which bifidobacteria predominate. However, for complex samples containing more diverse microbiota, the selectivity of mupirocin media is limited. Resistance to mupirocin has been demonstrated by many anaerobic bacteria, especially clostridia. The objective was to identify an antibiotic that inhibits the growth of clostridia and allows the growth of bifidobacteria, and to use the identified substance to develop a selective cultivation medium for bifidobacteria. The susceptibility of bifidobacteria and clostridia to 12 antibiotics was tested on agar using the disk diffusion method. Only norfloxacin inhibited the growth of clostridia and did not affect the growth of bifidobacteria. Using both pure cultures and faecal samples from infants, adults, calves, lambs, and piglets, the optimal concentration of norfloxacin in solid cultivation media was determined to be 200 mg/L. Our results showed that solid medium containing norfloxacin (200 mg/L) in combination with mupirocin (100 mg/L) and glacial acetic acid (1 mL/L) is suitable for the enumeration and isolation of bifidobacteria from faecal samples of different origins. PMID:25865525

  20. 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.

    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.

  1. Finding the lost open-circuit voltage in polymer solar cells by UV-ozone treatment of the nickel acetate anode buffer layer.

    PubMed

    Wang, Fuzhi; Sun, Gang; Li, Cong; Liu, Jiyan; Hu, Siqian; Zheng, Hua; Tan, Zhan'ao; Li, Yongfang

    2014-06-25

    Efficient polymer solar cells (PSCs) with enhanced open-circuit voltage (Voc) are fabricated by introducing solution-processed and UV-ozone (UVO)-treated nickel acetate (O-NiAc) as an anode buffer layer. According to X-ray photoelectron spectroscopy data, NiAc partially decomposed to NiOOH during the UVO treatment. NiOOH is a dipole species, which leads to an increase in the work function (as confirmed by ultraviolet photoemission spectroscopy), thus benefitting the formation of ohmic contact between the anode and photoactive layer and leading to increased Voc. In addition, the UVO treatment improves the wettability between the substrate and solvent of the active layer, which facilitates the formation of an upper photoactive layer with better morphology. Further, the O-NiAc layer can decrease the series resistance (Rs) and increase the parallel resistance (Rp) of the devices, inducing enhanced Voc in comparison with the as-prepared NiAc-buffered control devices without UVO treatment. For PSCs based on the P3HT:PCBM system, Voc increases from 0.50 to 0.60 V after the NiAc buffer layer undergoes UVO treatment. Similarly, in the P3HT:ICBA system, the Voc value of the device with a UVO-treated NiAc buffer layer increases from 0.78 to 0.88 V, showing an enhanced power conversion efficiency of 6.64%.

  2. Finding the lost open-circuit voltage in polymer solar cells by UV-ozone treatment of the nickel acetate anode buffer layer.

    PubMed

    Wang, Fuzhi; Sun, Gang; Li, Cong; Liu, Jiyan; Hu, Siqian; Zheng, Hua; Tan, Zhan'ao; Li, Yongfang

    2014-06-25

    Efficient polymer solar cells (PSCs) with enhanced open-circuit voltage (Voc) are fabricated by introducing solution-processed and UV-ozone (UVO)-treated nickel acetate (O-NiAc) as an anode buffer layer. According to X-ray photoelectron spectroscopy data, NiAc partially decomposed to NiOOH during the UVO treatment. NiOOH is a dipole species, which leads to an increase in the work function (as confirmed by ultraviolet photoemission spectroscopy), thus benefitting the formation of ohmic contact between the anode and photoactive layer and leading to increased Voc. In addition, the UVO treatment improves the wettability between the substrate and solvent of the active layer, which facilitates the formation of an upper photoactive layer with better morphology. Further, the O-NiAc layer can decrease the series resistance (Rs) and increase the parallel resistance (Rp) of the devices, inducing enhanced Voc in comparison with the as-prepared NiAc-buffered control devices without UVO treatment. For PSCs based on the P3HT:PCBM system, Voc increases from 0.50 to 0.60 V after the NiAc buffer layer undergoes UVO treatment. Similarly, in the P3HT:ICBA system, the Voc value of the device with a UVO-treated NiAc buffer layer increases from 0.78 to 0.88 V, showing an enhanced power conversion efficiency of 6.64%. PMID:24878826

  3. Acetate in mixotrophic growth medium affects photosystem II in Chlamydomonas reinhardtii and protects against photoinhibition.

    PubMed

    Roach, Thomas; Sedoud, Arezki; Krieger-Liszkay, Anja

    2013-10-01

    Chlamydomonas reinhardtii is a photoautotrophic green alga, which can be grown mixotrophically in acetate-supplemented media (Tris-acetate-phosphate). We show that acetate has a direct effect on photosystem II (PSII). As a consequence, Tris-acetate-phosphate-grown mixotrophic C. reinhardtii cultures are less susceptible to photoinhibition than photoautotrophic cultures when subjected to high light. Spin-trapping electron paramagnetic resonance spectroscopy showed that thylakoids from mixotrophic C. reinhardtii produced less (1)O2 than those from photoautotrophic cultures. The same was observed in vivo by measuring DanePy oxalate fluorescence quenching. Photoinhibition can be induced by the production of (1)O2 originating from charge recombination events in photosystem II, which are governed by the midpoint potentials (Em) of the quinone electron acceptors. Thermoluminescence indicated that the Em of the primary quinone acceptor (QA/QA(-)) of mixotrophic cells was stabilised while the Em of the secondary quinone acceptor (QB/QB(-)) was destabilised, therefore favouring direct non-radiative charge recombination events that do not lead to (1)O2 production. Acetate treatment of photosystem II-enriched membrane fragments from spinach led to the same thermoluminescence shifts as observed in C. reinhardtii, showing that acetate exhibits a direct effect on photosystem II independent from the metabolic state of a cell. A change in the environment of the non-heme iron of acetate-treated photosystem II particles was detected by low temperature electron paramagnetic resonance spectroscopy. We hypothesise that acetate replaces the bicarbonate associated to the non-heme iron and changes the environment of QA and QB affecting photosystem II charge recombination events and photoinhibition.

  4. Methyl Acetate and Its Singly Deuterated Isotopomers in the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Das, Ankan; Majumdar, Liton; Sahu, Dipen; Gorai, Prasanta; Sivaraman, B.; Chakrabarti, Sandip K.

    2015-07-01

    Methyl acetate ({{CH}}3{{COOCH}}3) has been recently observed by the IRAM 30 m radio telescope in Orion, though the presence of its deuterated isotopomers is yet to be confirmed. We therefore study the properties of various forms of methyl acetate, namely, {{CH}}3{{COOCH}}3, {{CH}}2{{DCOOCH}}3, and {{CH}}3{{COOCH}}2{{D}}. Our simulation reveals that these species could be produced efficiently in both gas and ice phases. Production of methyl acetate could follow radical-radical reaction between acetyl ({{CH}}3{CO}) and methoxy ({{CH}}3{{O}}) radicals. To predict abundances of {{CH}}3{{COOCH}}3 along with its two singly deuterated isotopomers and its two isomers (ethyl formate and hydroxyacetone), we prepare a gas-grain chemical network to study the chemical evolution of these molecules. Since gas-phase rate coefficients for methyl acetate and its related species are unknown, either we consider similar rate coefficients for similar types of reactions (by following existing databases) or we carry out quantum chemical calculations to estimate the unknown rate coefficients. For the surface reactions, we use adsorption energies of reactants from some earlier studies. Moreover, we perform quantum chemical calculations to obtain spectral properties of methyl acetate in infrared and sub-millimeter regions. We prepare two catalog files for the rotational transitions of {{CH}}2{{DCOOCH}}3 and {{CH}}3{{COOCH}}2{{D}} in JPL format, which could be useful for their detection in regions of interstellar media where {{CH}}3{{COOCH}}3 has already been observed.

  5. 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

  6. Growth of Chlamydomonas reinhardtii in acetate-free medium when co-cultured with alginate-encapsulated, acetate-producing strains of Synechococcus sp. PCC 7002

    DOE PAGES

    Therien, Jesse B.; Zadvornyy, Oleg A.; Posewitz, Matthew C.; Bryant, Donald A.; Peters, John W.

    2014-10-18

    The model alga Chlamydomonas reinhardtii requires acetate as a co-substrate for optimal production of lipids, and the addition of acetate to culture media has practical and economic implications for algal biofuel production. We demonstrate the growth of C. reinhardtii on acetate provided by mutant strains of the cyanobacterium Synechococcus sp. PCC7002.

  7. Buffer Capacity: An Undergraduate Laboratory Experiment.

    ERIC Educational Resources Information Center

    Russo, Steven O.; Hanania, George I. H.

    1987-01-01

    Describes a quantitative experiment designed to demonstrate buffer action and the measurement of buffer capacity. Discusses how to make acetate buffers, determine their buffer capacity, plot the capacity/pH curve, and interpret the data obtained. (TW)

  8. Tris-sucrose buffer system: a new specially designed medium for extracellular invertase production by immobilized cells of isolated yeast Cryptococcus laurentii MT-61.

    PubMed

    Aydogan, Mehmet Nuri; Taskin, Mesut; Canli, Ozden; Arslan, Nazli Pinar; Ortucu, Serkan

    2014-01-01

    The aims of the present study were to isolate new yeasts with high extracellular (exo) invertase activity and to investigate the usability of buffer systems as invertase production media by immobilized yeast cells. Among 70 yeast isolates, Cryptococcus laurentii MT-61 had the highest exo-invertase activity. Immobilization of yeast cells was performed using sodium alginate. Higher exo-invertase activity for immobilized cells was achieved in tris-sucrose buffer system (TSBS) compared to sodium acetate buffer system and potassium phosphate buffer system. TSBS was prepared by dissolving 30 g of sucrose in 1 L of tris buffer solution. The optimum pH, temperature, and incubation time for invertase production with immobilized cells were determined as 8.0, 35 °C and 36 h in TSBS, respectively. Under optimized conditions, maximum exo-invertase activity was found to be 28.4 U/mL in sterile and nonsterile TSBS. Immobilized cells could be reused in 14 and 12 successive cycles in sterile and nonsterile TSBS without any loss in the maximum invertase activity, respectively. This is the first report which showed that immobilized microbial cells could be used as a biocatalyst for exo-invertase production in buffer system. As an additional contribution, a new yeast strain with high invertase activity was isolated.

  9. Potentially lethal and DNA radiation damage: similarities in inhibition of repair by medium containing D/sub 2/O and by hypertonic buffer

    SciTech Connect

    Ben-Hur, E.; Utsumi, H.; Elkind, M.M.

    1980-10-01

    Killing of log-phase V79 Chinese hamster cells by ionizing radiation is enhanced when cells are treated immediately after irradiation with anisotonic phosphate-buffered saline or with medium containing 90% D/sub 2/O. These treatments are not toxic to unirradiated cells. In medium containing D/sub 2/O, cells are unable to repair sublethal damage; however, repair occurs after a shift to normal medium. Thus, as is observed with anisotonic buffer, enhanced killing by medium containing D/sub 2/O does not prevent cells from repairing sublethal damage. Further aspects of the enhanced expression of potentially lethal damage by medium containing D/sub 2/O and by anisotonic buffer are also similar. For example, both are largely ineffective after treatments involving nonionizing radiation, and both treatments retard the repair of DNA breaks. From the foregoing, and the partial overlapping of enhanced killing due to medium containing D/sub 2/O and due to hypertonic saline, we infer that the latter treatments affect the repair, or reparability, of the same sensitive targets.

  10. Improvement of sensitivity of electrolyte cathode discharge atomic emission spectrometry (ELCAD-AES) for mercury using acetic acid medium.

    PubMed

    Shekhar, R

    2012-05-15

    A method has been developed to improve the sensitivity of the electrolyte cathode discharge atomic emission spectrometry (ELCAD-AES) for mercury determination. Effects of various low molecular weight organic solvents at different volume percentages as well as at different acid molarities on the mercury signal were investigated using ELCAD-AES. The addition of few percent of organic solvent, acetic acid produced significant enhancement in mercury signal. Acetic acid of 5% (v/v) with the 0.2M acidity has been found to give 500% enhancement for mercury signal in flow injection mode. Under the optimized parameters the repeatability, expressed as the percentage relative standard deviation of spectral peak area for mercury with 5% acetic acid was found to be 10% for acid blank solution and 5% for 20 ng/mL mercury standard based on multiple measurements with a multiple sample loading in flow injection mode. Limit of detection of this method was determined to be 2 ng/mL for inorganic mercury. The proposed method has been validated by determining mercury in certified reference materials, Tuna fish (IAEA-350) and Aquatic plant (BCR-060). Accuracy of the method for the mercury determination in the reference materials has been found to be between 3.5% and 5.9%. This study enhances the utility of ELCAD-AES for various types of biological and environmental materials to quantify total mercury at very low levels. PMID:22483872

  11. Improvement of sensitivity of electrolyte cathode discharge atomic emission spectrometry (ELCAD-AES) for mercury using acetic acid medium.

    PubMed

    Shekhar, R

    2012-05-15

    A method has been developed to improve the sensitivity of the electrolyte cathode discharge atomic emission spectrometry (ELCAD-AES) for mercury determination. Effects of various low molecular weight organic solvents at different volume percentages as well as at different acid molarities on the mercury signal were investigated using ELCAD-AES. The addition of few percent of organic solvent, acetic acid produced significant enhancement in mercury signal. Acetic acid of 5% (v/v) with the 0.2M acidity has been found to give 500% enhancement for mercury signal in flow injection mode. Under the optimized parameters the repeatability, expressed as the percentage relative standard deviation of spectral peak area for mercury with 5% acetic acid was found to be 10% for acid blank solution and 5% for 20 ng/mL mercury standard based on multiple measurements with a multiple sample loading in flow injection mode. Limit of detection of this method was determined to be 2 ng/mL for inorganic mercury. The proposed method has been validated by determining mercury in certified reference materials, Tuna fish (IAEA-350) and Aquatic plant (BCR-060). Accuracy of the method for the mercury determination in the reference materials has been found to be between 3.5% and 5.9%. This study enhances the utility of ELCAD-AES for various types of biological and environmental materials to quantify total mercury at very low levels.

  12. Effects of acetic acid and arginine on pH elevation and growth of Bacillus licheniformis in an acidified cucumber juice medium.

    PubMed

    Yang, Zhenquan; Meng, Xia; Breidt, Frederick; Dean, Lisa L; Arritt, Fletcher M

    2015-04-01

    Bacillus licheniformis has been shown to cause pH elevation in tomato products having an initial pH below 4.6 and metabiotic effects that can lead to the growth of pathogenic bacteria. Because of this, the organism poses a potential risk to acidified vegetable products; however, little is known about the growth and metabolism of this organism in these products. To clarify the mechanisms of pH change and growth of B. licheniformis in vegetable broth under acidic conditions, a cucumber juice medium representative of a noninhibitory vegetable broth was used to monitor changes in pH, cell growth, and catabolism of sugars and amino acids. For initial pH values between pH 4.1 to 6.0, pH changes resulted from both fermentation of sugar (lowering pH) and ammonia production (raising pH). An initial pH elevation occurred, with starting pH values of pH 4.1 to 4.9 under both aerobic and anaerobic conditions, and was apparently mediated by the arginine deiminase reaction of B. licheniformis. This initial pH elevation was prevented if 5 mM or greater acetic acid was present in the brine at the same pH. In laboratory media, under favorable conditions for growth, data indicated that growth of the organism was inhibited at pH 4.6 with protonated acetic acid concentrations of 10 to 20 mM, corresponding to 25 to 50 mM total acetic acid; however, growth inhibition required greater than 300 mM citric acid (10-fold excess of the amount in processed tomato products) products under similar conditions. The data indicate that growth and pH increase by B. licheniformis may be inhibited by the acetic acid present in most commercial acidified vegetable products but not by the citric acid in many tomato products.

  13. Optimization of moisture content for wheat seedling germination in a cellulose acetate medium for a space flight experiment.

    PubMed

    Johnson, C F; Dreschel, T W; Brown, C S; Wheeler, R M

    1996-01-01

    The Porous Tube Plant Nutrient Delivery System (PTPNDS), a hydrophilic, microporous ceramic tube hydroponic system designed for microgravity, will be tested in a middeck locker of the Space Shuttle. The flight experiment will focus on hardware operation and assess its ability to support seed germination and early seedling growth in microgravity. The water controlling system of the PTPNDS hardware has been successfully tested during the parabolic flight of the KC-135. One challenge to the development of the space flight experiment was to devise a method of holding seeds to the cylindrical porous tube. The seed-holder must provide water and air to the seed, absorb water from the porous tube, withstand sterilization, provide a clear path for shoots and roots to emerge, and be composed of flight qualified materials. In preparation for the flight experiment, a wheat seed-holder has been designed that utilizes a cellulose acetate plug to facilitate imbibition and to hold the wheat seeds in contact with the porous tube in the correct orientation during the vibration of launch and the microgravity environment of orbit. Germination and growth studies with wheat at a range of temperatures showed that optimal moisture was 78% (by weight) in the cellulose acetate seed holders. These and other design considerations are discussed.

  14. Optimization of moisture content for wheat seedling germination in a cellulose acetate medium for a space flight experiment

    NASA Astrophysics Data System (ADS)

    Johnson, C. F.; Dreschel, T. W.; Brown, C. S.; Wheeler, R. M.

    1996-01-01

    The Porous Tube Plant Nutrient Delivery System (PTPNDS), a hydrophilic, microporous ceramic tube hydroponic system designed for microgravity, will be tested in a middeck locker of the Space Shuttle. The flight experiment will focus on hardware operation and assess its ability to support seed germination and early seedling growth in microgravity. The water controlling system of the PTPNDS hardware has been successfully tested during the parabolic flight of the KC-135. One challenge to the development of the space flight experiment was to devise a method of holding seeds to the cylindrical porous tube. The seed-holder must provide water and air to be seed, absorb water from the porous tube, withstand sterilization, provide a clear path for shoots and roots to emerge, and be composed of flight qualified materials. In preparation for the flight experiment, a wheat seed-holder has been designed that utilizes a cellulose acetate plug to facilitate imbibition and to hold the wheat seeds in contact with the porous tube in the correct orientation during the vibration of launch and the microgravity environment of orbit. Germination and growth studies with wheat at a range of temperatures showed that optimal moisture was 78% (by weight) in the cellulose acetate seed holders. These and other design considerations are discussed.

  15. Optimization of moisture content for wheat seedling germination in a cellulose acetate medium for a space flight experiment.

    PubMed

    Johnson, C F; Dreschel, T W; Brown, C S; Wheeler, R M

    1996-01-01

    The Porous Tube Plant Nutrient Delivery System (PTPNDS), a hydrophilic, microporous ceramic tube hydroponic system designed for microgravity, will be tested in a middeck locker of the Space Shuttle. The flight experiment will focus on hardware operation and assess its ability to support seed germination and early seedling growth in microgravity. The water controlling system of the PTPNDS hardware has been successfully tested during the parabolic flight of the KC-135. One challenge to the development of the space flight experiment was to devise a method of holding seeds to the cylindrical porous tube. The seed-holder must provide water and air to the seed, absorb water from the porous tube, withstand sterilization, provide a clear path for shoots and roots to emerge, and be composed of flight qualified materials. In preparation for the flight experiment, a wheat seed-holder has been designed that utilizes a cellulose acetate plug to facilitate imbibition and to hold the wheat seeds in contact with the porous tube in the correct orientation during the vibration of launch and the microgravity environment of orbit. Germination and growth studies with wheat at a range of temperatures showed that optimal moisture was 78% (by weight) in the cellulose acetate seed holders. These and other design considerations are discussed. PMID:11538804

  16. Optimization of moisture content for wheat seedling germination in a cellulose acetate medium for a space flight experiment

    NASA Technical Reports Server (NTRS)

    Johnson, C. F.; Dreschel, T. W.; Brown, C. S.; Wheeler, R. M.

    1996-01-01

    The Porous Tube Plant Nutrient Delivery System (PTPNDS), a hydrophilic, microporous ceramic tube hydroponic system designed for microgravity, will be tested in a middeck locker of the Space Shuttle. The flight experiment will focus on hardware operation and assess its ability to support seed germination and early seedling growth in microgravity. The water controlling system of the PTPNDS hardware has been successfully tested during the parabolic flight of the KC-135. One challenge to the development of the space flight experiment was to devise a method of holding seeds to the cylindrical porous tube. The seed-holder must provide water and air to the seed, absorb water from the porous tube, withstand sterilization, provide a clear path for shoots and roots to emerge, and be composed of flight qualified materials. In preparation for the flight experiment, a wheat seed-holder has been designed that utilizes a cellulose acetate plug to facilitate imbibition and to hold the wheat seeds in contact with the porous tube in the correct orientation during the vibration of launch and the microgravity environment of orbit. Germination and growth studies with wheat at a range of temperatures showed that optimal moisture was 78% (by weight) in the cellulose acetate seed holders. These and other design considerations are discussed.

  17. Optimization of moisture content for wheat seedling germination in a cellulose acetate medium for a space flight experiment

    NASA Technical Reports Server (NTRS)

    Johnson, Corinne F.; Dreschel, Thomas W.; Brown, Christopher S.; Wheeler, Raymond M.

    1994-01-01

    The Porous Tube Plant Nutrient Delivery System (PTPNDS), a hydrophilic, microporous ceramic tube hydroponic system designed for microgravity, will be tested in a middeck locker of the Space Shuttle. The flight experiment will focus on hardware operation and assess its ability to support seed germination and early seedling growth in microgravity. The water controlling system of the PTPNDS hardware has been successfully tested during the parabolic flight of the KC-135. One challenge to the development of the spaceflight experiment was to devise a method of holding seeds to the cylindrical porous tube. The seed holder must provide water and air to the seed, absorb water from the porous tube, withstand sterilization, provide a clear path for shoots and roots to emerge, and be composed of flight qualified materials. In preparation for the flight experiment, a wheat seed-holder has been designed that utilizes a cellulose acetate plug to facilitate imbibition and to hold the wheat seeds in contact with the porous tube in the correct orientation during the vibration of launch and the microgravity environment of orbit. Germination and growth studies with wheat at a range of temperatures showed that optimal moisture was 78% (by weight) in the cellulose acetate seed holders. These and other design considerations are discussed.

  18. Effects of Growth Medium on Matrix-Assisted Laser Desorption–Ionization Time of Flight Mass Spectra: a Case Study of Acetic Acid Bacteria

    PubMed Central

    Wieme, Anneleen D.; Spitaels, Freek; Aerts, Maarten; De Bruyne, Katrien; Van Landschoot, Anita

    2014-01-01

    The effect of the growth medium used on the matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectra generated and its consequences for species and strain level differentiation of acetic acid bacteria (AAB) were determined by using a set of 25 strains. The strains were grown on five different culture media that yielded a total of more than 600 mass spectra, including technical and biological replicates. The results demonstrate that the culture medium can have a profound effect on the mass spectra of AAB as observed in the presence and varying signal intensities of peak classes, in particular when culture media do not sustain optimal growth. The observed growth medium effects do not disturb species level differentiation but strongly affect the potential for strain level differentiation. The data prove that a well-constructed and robust MALDI-TOF mass spectrometry identification database should comprise mass spectra of multiple reference strains per species grown on different culture media to facilitate species and strain level differentiation. PMID:24362425

  19. Influence of the finite linewidth of the laser radiation spectrum on the shape of the coherent population trapping resonance line in an optically dense medium with a buffer gas

    SciTech Connect

    Barantsev, K. A. Popov, E. N.; Litvinov, A. N.

    2015-11-15

    The theory of coherent population trapping resonance is developed for the finite linewidth of the laser radiation spectrum in an optically dense medium of Λ atoms in a cell with a buffer gas. Equations are derived for the atomic density matrix and laser emission spectrum transfer in a cell with working and buffer gases at a finite temperature. The dependence of the quality factor of coherent population trapping resonance on the linewidth of the laser radiation spectrum is studied by measuring transmitted radiation and fluorescence signals.

  20. Growth of Chlamydomonas reinhardtii in acetate-free medium when co-cultured with alginate-encapsulated, acetate-producing strains of Synechococcus sp. PCC 7002

    SciTech Connect

    Therien, Jesse B.; Zadvornyy, Oleg A.; Posewitz, Matthew C.; Bryant, Donald A.; Peters, John W.

    2014-10-18

    The model alga Chlamydomonas reinhardtii requires acetate as a co-substrate for optimal production of lipids, and the addition of acetate to culture media has practical and economic implications for algal biofuel production. We demonstrate the growth of C. reinhardtii on acetate provided by mutant strains of the cyanobacterium Synechococcus sp. PCC7002.

  1. Further investigations of enhancing effect of medium-chain triglycerides on d-alpha-tocopherol acetate absorption from lecithin-dispersed preparations in rat small intestine.

    PubMed

    Fukui, E; Tabuchi, H; Kurosaki, Y; Nakayama, T; Kimura, T

    1989-12-01

    The effect of medium-chain triglycerides (MCTG) in lecithin-dispersed d-alpha-tocopherol acetate (VEA) preparation on intestinal absorption of VEA was investigated in rats using the in situ loop experiment. When VEA preparations containing soybean phosphatidylcholine (PC) and various amounts of MCTG were administered, the amount of VEA absorbed in 2 h was not significantly different among them. However, the amounts of total VE, sum of VEA and d-alpha-tocopherol (VE), remaining in the luminal fluid and the intestinal tissue were dependent on the MCTG content. Total VE remaining in the intestinal tissue after the administration of a VEA/PC/MCTG (5/16/1 by weight) preparation was nearly twice of VEA/PC (5/16) preparation, although the effect of MCTG varied with the increase or decrease in the MCTG content. Moreover, the increased tissue accumulation of total VE by the VEA/PC/MCTG (5/16/1) preparation resulted in an increase in the plasma VE concentration after the removal of the luminal fluid. No effect of pretreatment with PC/MCTG (1/1) dispersion on the tissue accumulation of total VE from VEA/PC (5/16) preparation was observed. Furthermore, the plasma concentration of VE from VEA and/or VE taken up in the tissue from the VEA/PC preparation was not increased by the treatment with the PC/MCTG dispersion. These results suggest that MCTG should coexist in the luminal VEA preparation to enhance the mucosal uptake. A similar enhancing effect was also observed by the addition of the metabolite of MCTG, a medium-chain fatty acid.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Electrochemical behaviour of technetium in acetic buffer

    NASA Astrophysics Data System (ADS)

    Courson, O.; Le Naour, C.; David, F.; Bolyos, A.; Maslennikov, A.; Papadopoulos, N.

    1999-01-01

    In order to understand the complex reduction mechanism of pertechnetate ions on mercury electrode we have developed electrochemical techniques which use an additional time parameter to the classical methods applied on mercury microelectrode: 3 Dimensional polarography and 3D differential capacity measurements have been investigated in addition with coulometry, cyclic voltammetry, and radioactivity determinations. We have concluded that the first VII→III reduction wave, which have been described in literature, has to be associated with the successive VII→V reactions followed by the disproportion of Tc(V) and formation of Tc(VI) and insoluble tetravalent species which are adsorbed on the electrode and reduced to trivalent ions. Then, reduction of Tc(III) to Tc(0) is reached through Tc(II) and Tc(I) intermediate species. The intermediates are characterised depending on the time window of observation.

  3. Enhancing effect of medium-chain triglycerides on intestinal absorption of d-alpha-tocopherol acetate from lecithin-dispersed preparations in the rat.

    PubMed

    Fukui, E; Kurohara, H; Kageyu, A; Kurosaki, Y; Nakayama, T; Kimura, T

    1989-02-01

    The effect of formulations of lecithin-dispersed preparation on the absorption of d-alpha-tocopherol acetate (VEA) from the small intestine was investigated in rats. When lecithin-dispersed preparations containing VEA or polysorbate 80 (PS-80)-solubilized solution of VEA were intraduodenally administered, VEA was hydrolyzed to d-alpha-tocopherol (VE) and was not detected in the plasma nor in the thoracic lymph. The maximum plasma concentration (Cmax) of VE after the intraduodenal administration of a preparation consisting of VEA, soybean phosphatidylcholine (PC) and medium-chain triglycerides (MCTG) (VEA/PC/MCTG, 5/16/1 by weight) was highest among the VEA preparations, and PS-80-solubilized solution gave the lowest Cmax. AUC of VE up to 24 h was also increased by the addition of MCTG to VEA/PC preparation. In the thoracic duct-fistula rat, the transport of VE into the thoracic lymph was increased by the administration of the VEA/PC/MCTG preparation significantly more than the VEA/PC preparation; the cumulative amounts of VE recovered in the thoracic lymph up to 24 h were 23.2 +/- 0.5% and 10.9 +/- 1.5% of dose, respectively. The plasma concentration of VE was not increased in the thoracic duct-fistula rat even after the intraduodenal administration of VEA preparations, suggesting that VE is not transported directly to the systemic circulation, but by way of the lymphatic route. The lymphatic transport of VE following the intraduodenal administration of VEA/PC/MCTG preparation was markedly diminished by the simultaneous administration of Pluronic L-81 emulsion, an inhibitor of chylomicron formation. It is suggested that the chylomicron is essential to the lymphatic transport of VE from VEA preparations.

  4. Buffer capacity of biologics--from buffer salts to buffering by antibodies.

    PubMed

    Karow, Anne R; Bahrenburg, Sven; Garidel, Patrick

    2013-01-01

    Controlling pH is essential for a variety of biopharmaceutical process steps. The chemical stability of biologics such as monoclonal antibodies is pH-dependent and slightly acidic conditions are favorable for stability in a number of cases. Since control of pH is widely provided by added buffer salts, the current study summarizes the buffer characteristics of acetate, citrate, histidine, succinate, and phosphate buffers. Experimentally derived values largely coincide with values calculated from a model that had been proposed in 1922 by van Slyke. As high concentrated protein formulations become more and more prevalent for biologics, the self-buffering potential of proteins becomes of relevance. The current study provides information on buffer characteristics for pH ranges down to 4.0 and up to 8.0 and shows that a monoclonal antibody at 50 mg/mL exhibits similar buffer capacity as 6 mM citrate or 14 mM histidine (pH 5.0-6.0). Buffer capacity of antibody solutions scales linearly with protein concentration up to more than 200 mg/mL. At a protein concentration of 220 mg/mL, the buffer capacity resembles the buffer capacity of 30 mM citrate or 50 mM histidine (pH 5.0-6.0). The buffer capacity of monoclonal antibodies is practically identical at the process relevant temperatures 5, 25, and 40°C. Changes in ionic strength of ΔI=0.15, in contrast, can alter the buffer capacity up to 35%. In conclusion, due to efficient self-buffering by antibodies in the pH range of favored chemical stability, conventional buffer excipients could be dispensable for pH stabilization of high concentrated protein solutions.

  5. Buffer Biology.

    ERIC Educational Resources Information Center

    Morgan, Kelly

    2000-01-01

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

  6. Antimicrobial activity of borate-buffered solutions.

    PubMed Central

    Houlsby, R D; Ghajar, M; Chavez, G O

    1986-01-01

    A minimal salts medium adjusted to physiological pH and osmolality was buffered with either 0.3% phosphate or 1.2% borate and evaluated for antimicrobial activity. The borate-buffered medium, either with or without a carbon source, exhibited significant antimicrobial activity against 15 Pseudomonas strains, 12 strains of enteric bacteria, and 7 strains of staphylococci. The borate-buffered system appears suitable for use as a generic vehicle for ophthalmic pharmaceutical agents. PMID:3729341

  7. Initial inhomogeneity-induced crazy-clock behavior in the iodate-arsenous acid reaction in a buffered medium under stirred batch conditions.

    PubMed

    Valkai, László; Csekő, György; Horváth, Attila K

    2015-09-14

    It is unambiguously demonstrated that in the case of an autocatalytic reaction, initial inhomogeneities induced by the imperfectly mixed part of the overall volume may result in a serious irreproducibility of the individual kinetic runs. A statistically meaningful number of repetitions, however, gives rise to a reproducible cumulative probability distribution curve often referred to as a support of the stochastic feature. The iodate-arsenous acid reaction being autocatalytic with respect to both iodide and hydrogen ions displays clock behavior. However, the time lag necessary for the appearance of iodine, even in buffered solution, varies in an apparently random manner. Careful analysis of the variation of the different parameters like stirring rate, overall volume, geometry of the reactor and the way of mixing the reactants led us to conclude that the fate of the individual samples is determined at the initial stage when the reacting system is per se inhomogeneous. The place, the size of the so-called ignition volume, where the reacting system is imperfectly stirred, as well as the residence time spent there by the imperfectly mixed reactants all seem to depend on external factors. PMID:26239390

  8. Mesoxalaldehyde acetals

    SciTech Connect

    Gordeeva, G.N.; Kalashnikov, S.M.; Popov, Yu.N.; Kruglov, E.A.; Imashev, U.B.

    1987-11-10

    The treatment of methylglyoxal acetals by alkyl nitrites in the presence of the corresponding aliphatic alcohols and hydrochloric acid leads to the formation of linear mesoxalaldehyde acetals, whose structure was established by NMR spectroscopy and mass spectrometry. The major pathways for the decomposition of these molecules upon electron impact were established.

  9. Kinetic buffers.

    PubMed

    Alibrandi, Giuseppe; Fabbrizzi, Luigi; Licchelli, Maurizio; Puglisi, Antonio

    2015-01-12

    This paper proposes a new type of molecular device that is able to act as an inverse proton sponge to slowly decrease the pH inside a reaction vessel. This makes the automatic monitoring of the concentration of pH-sensitive systems possible. The device is a composite formed of an alkyl chloride, which kinetically produces acidity, and a buffer that thermodynamically modulates the variation in pH value. Profiles of pH versus time (pH-t plots) have been generated under various experimental conditions by computer simulation, and the device has been tested by carrying out automatic spectrophotometric titrations, without using an autoburette. To underline the wide variety of possible applications, this new system has been used to realize and monitor HCl uptake by a di-copper(II) bistren complex in a single run, in a completely automatic experiment.

  10. Enhancement of oral bioavailability of d-alpha-tocopherol acetate by lecithin-dispersed aqueous preparation containing medium-chain triglycerides in rats.

    PubMed

    Kimura, T; Fukui, E; Kageyu, A; Kurohara, H; Kurosaki, Y; Nakayama, T; Morita, Y; Shibusawa, K; Ohsawa, S; Takeda, Y

    1989-02-01

    In order to evaluate oral dosage forms of d-alpha-tocopherol acetate (VEA), d-alpha-tocopherol (VE) concentration in the plasma was examined following oral administration of three VEA preparations; lecithin-dispersed aqueous preparation, polysorbate 80 (PS-80)-solubilized aqueous solution and soybean oil solution. The lecithin-dispersed preparation gave the highest Cmax and the largest AUC0-24h, while Tmax was delayed. In the thoracic duct fistula rat, no increase in VE plasma concentration was observed after intraduodenal administration of lecithin-dispersed VEA preparation via the lymphatic route. The delayed Tmax and prolonged VE plasma concentration obtained with the lecithin-dispersed preparation in comparison with PS-80-solubilized aqueous solution could be explained by the different route of absorption.

  11. Buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions: from protein buffer capacity prediction to bioprocess applications.

    PubMed

    Bahrenburg, Sven; Karow, Anne R; Garidel, Patrick

    2015-04-01

    Protein therapeutics, including monoclonal antibodies (mAbs), have significant buffering capacity, particularly at concentrations>50 mg/mL. This report addresses pH-related issues critical to adoption of self-buffered monoclonal antibody formulations. We evaluated solution conditions with protein concentrations ranging from 50 to 250 mg/mL. Samples were both buffer-free and conventionally buffered with citrate. Samples were non-isotonic or adjusted for isotonicity with NaCl or trehalose. Studies included accelerated temperature stability tests, shaking stability studies, and pH changes in infusion media as protein concentrate is added. We present averaged buffering slopes of capacity that can be applied to any mAb and present a general method for calculating buffering capacity of buffer-free, highly concentrated antibody liquid formulations. In temperature stability tests, neither buffer-free nor conventionally buffered solution conditions showed significant pH changes. Conventionally buffered solutions showed significantly higher opalescence than buffer-free ones. In general, buffer-free solution conditions showed less aggregation than conventionally buffered solutions. Shaking stability tests showed no differences between buffer-free and conventionally buffered solutions. "In-use" preparation experiments showed that pH in infusion bag medium can rapidly approximate that of self-buffered protein concentrate as concentrate is added. In summary, the buffer capacity of proteins can be predicted and buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions. PMID:25641961

  12. Buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions: from protein buffer capacity prediction to bioprocess applications.

    PubMed

    Bahrenburg, Sven; Karow, Anne R; Garidel, Patrick

    2015-04-01

    Protein therapeutics, including monoclonal antibodies (mAbs), have significant buffering capacity, particularly at concentrations>50 mg/mL. This report addresses pH-related issues critical to adoption of self-buffered monoclonal antibody formulations. We evaluated solution conditions with protein concentrations ranging from 50 to 250 mg/mL. Samples were both buffer-free and conventionally buffered with citrate. Samples were non-isotonic or adjusted for isotonicity with NaCl or trehalose. Studies included accelerated temperature stability tests, shaking stability studies, and pH changes in infusion media as protein concentrate is added. We present averaged buffering slopes of capacity that can be applied to any mAb and present a general method for calculating buffering capacity of buffer-free, highly concentrated antibody liquid formulations. In temperature stability tests, neither buffer-free nor conventionally buffered solution conditions showed significant pH changes. Conventionally buffered solutions showed significantly higher opalescence than buffer-free ones. In general, buffer-free solution conditions showed less aggregation than conventionally buffered solutions. Shaking stability tests showed no differences between buffer-free and conventionally buffered solutions. "In-use" preparation experiments showed that pH in infusion bag medium can rapidly approximate that of self-buffered protein concentrate as concentrate is added. In summary, the buffer capacity of proteins can be predicted and buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions.

  13. Biodegradation of cellulose acetate by Neisseria sicca.

    PubMed

    Sakai, K; Yamauchi, T; Nakasu, F; Ohe, T

    1996-10-01

    Bacteria capable of assimilating cellulose acetate, strains SB and SC, were isolated from soil on a medium containing cellulose acetate as a carbon source, and identified as Neisseria sicca. Both strains degraded cellulose acetate membrane filters (degree of substitution, DS, mixture of 2.8 and 2.0) and textiles (DS, 2.34) in a medium containing cellulose acetate (DS, 2.34) or its oligomer, but were not able to degrade these materials in a medium containing cellobiose octaacetate. Biodegradation of cellulose acetate (DS, 1.81 and 2.34) on the basis of biochemical oxygen demand reached 51 and 40% in the culture of N. sicca SB and 60 and 45% in the culture of N. sicca SC within 20 days. A decrease in the acetyl content of degraded cellulose acetate films and powder was confirmed by infrared and nuclear magnetic resonance analyses. After 10-day cultivation of N. sicca SB and SC, the number-average molecular weight of residual cellulose acetate decreased by 9 and 5%, respectively. Activities of enzymes that released acetic acid and produced reducing sugars from cellulose acetate were mainly present in the culture supernatant. Reactivity of enzymes for cellulose acetate (DS, 1.81) was higher than that for cellulose acetate (DS, 2.34).

  14. Ethyl acetate

    Integrated Risk Information System (IRIS)

    Ethyl acetate ; CASRN 141 - 78 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  15. Phenylmercuric acetate

    Integrated Risk Information System (IRIS)

    Phenylmercuric acetate ; CASRN 62 - 38 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  16. Vinyl acetate

    Integrated Risk Information System (IRIS)

    Vinyl acetate ; CASRN 108 - 05 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  17. Ammonium acetate

    Integrated Risk Information System (IRIS)

    Ammonium acetate ; CASRN 631 - 61 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  18. Thallium acetate

    Integrated Risk Information System (IRIS)

    Jump to main content . Integrated Risk Information System Recent Additions | Contact Us Search : All EPA IRIS • You are here : EPA Home • Research • Environmental Assessment • IRIS • IRIS Summaries Redirect Page As of September 30 , 2009 , the assessment summary for Thallium acetate is included in t

  19. Application of cellulose acetate for controlled release of thymol.

    PubMed

    Milovanovic, Stoja; Markovic, Darka; Aksentijevic, Ksenija; Stojanovic, Dusica B; Ivanovic, Jasna; Zizovic, Irena

    2016-08-20

    Cellulose acetate (CA) was investigated as a carrier towards development of material with controlled release of thymol as a natural substance with strong antibacterial properties using high pressure techniques. Effect of thymol content on CA was confirmed by SEM, FTIR and DSC methods. Kinetic of thymol release from CA was tested using simulated gastric and intestinal fluids (hydrochloric acid and phosphate buffer saline). Results were correlated with Korsmeyer-Peppas and Weibull model. Depending on the thymol content and chemical nature of the release medium, the time of thymol release varied from one to three days indicating CA as a promising carrier of thymol with potential uses from medicine to agriculture. The impregnated CA showed antibacterial activity against 23 tested bacterial strains including methicillin-resistant Staphylococcus aureus (MRSA) which is particularly important bearing in mind that this strain causes fatal infections in humans and animals. PMID:27178940

  20. Application of cellulose acetate for controlled release of thymol.

    PubMed

    Milovanovic, Stoja; Markovic, Darka; Aksentijevic, Ksenija; Stojanovic, Dusica B; Ivanovic, Jasna; Zizovic, Irena

    2016-08-20

    Cellulose acetate (CA) was investigated as a carrier towards development of material with controlled release of thymol as a natural substance with strong antibacterial properties using high pressure techniques. Effect of thymol content on CA was confirmed by SEM, FTIR and DSC methods. Kinetic of thymol release from CA was tested using simulated gastric and intestinal fluids (hydrochloric acid and phosphate buffer saline). Results were correlated with Korsmeyer-Peppas and Weibull model. Depending on the thymol content and chemical nature of the release medium, the time of thymol release varied from one to three days indicating CA as a promising carrier of thymol with potential uses from medicine to agriculture. The impregnated CA showed antibacterial activity against 23 tested bacterial strains including methicillin-resistant Staphylococcus aureus (MRSA) which is particularly important bearing in mind that this strain causes fatal infections in humans and animals.

  1. Acetate dialysate versus bicarbonate dialysate: a continuing controversy.

    PubMed

    Diamond, S M; Henrich, W L

    1987-01-01

    The use of bicarbonate dialysate as the buffer during routine dialysis is growing. This discussion reviews several of the comparative trials in which bicarbonate and acetate buffers have been tested. Effects of the two buffers on BP, cardiac function, and pulmonary performance are discussed. Costs of the two systems are also compared. Patients who seem most likely to benefit from bicarbonate dialysate include those with a reduced muscle mass in whom a high sodium dialysate has not prevented hypotension. PMID:3028133

  2. 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.

  3. 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

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

    SciTech Connect

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

    2015-02-19

    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 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.

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

    DOE PAGES

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

    2015-02-19

    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

  6. Common data buffer

    NASA Technical Reports Server (NTRS)

    Byrne, F.

    1981-01-01

    Time-shared interface speeds data processing in distributed computer network. Two-level high-speed scanning approach routes information to buffer, portion of which is reserved for series of "first-in, first-out" memory stacks. Buffer address structure and memory are protected from noise or failed components by error correcting code. System is applicable to any computer or processing language.

  7. Influence of cell culture medium composition on in vitro dissolution behavior of a fluoride-containing bioactive glass.

    PubMed

    Shah, Furqan A; Brauer, Delia S; Wilson, Rory M; Hill, Robert G; Hing, Karin A

    2014-03-01

    Bioactive glasses are used clinically for bone regeneration, and their bioactivity and cell compatibility are often characterized in vitro, using physiologically relevant test solutions. The aim of this study was to show the influence of varying medium characteristics (pH, composition, presence of proteins) on glass dissolution and apatite formation. The dissolution behavior of a fluoride-containing bioactive glass (BG) was investigated over a period of one week in Eagle's Minimal Essential Medium with Earle's Salts (MEM), supplemented with either, (a) acetate buffer, (b) 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer, (c) HEPES + carbonate, or (d) HEPES + carbonate + fetal bovine serum. Results show pronounced differences in pH, ion release, and apatite formation over 1 week: Despite its acidic pH (pH 5.8 after BG immersion, as compared to pH 7.4-8.3 for HEPES-containing media), apatite formation was fastest in acetate buffered (HEPES-free) MEM. Presence of carbonate resulted in formation of calcite (calcium carbonate). Presence of serum proteins, on the other hand, delayed apatite formation significantly. These results confirm that the composition and properties of a tissue culture medium are important factors during in vitro experiments and need to be taken into consideration when interpreting results from dissolution or cell culture studies. PMID:23554092

  8. 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

  9. Aluminum elution and precipitation in glass vials: effect of pH and buffer species.

    PubMed

    Ogawa, Toru; Miyajima, Makoto; Wakiyama, Naoki; Terada, Katsuhide

    2015-02-01

    Inorganic extractables from glass vials may cause particle formation in the drug solution. In this study, the ability of eluting Al ion from borosilicate glass vials, and tendencies of precipitation containing Al were investigated using various pHs of phosphate, citrate, acetate and histidine buffer. Through heating, all of the buffers showed that Si and Al were eluted from glass vials in ratios almost the same as the composition of borosilicate glass, and the amounts of Al and Si from various buffer solutions at pH 7 were in the following order: citrate > phosphate > acetate > histidine. In addition, during storage after heating, the Al concentration at certain pHs of phosphate and acetate buffer solution decreased, suggesting the formation of particles containing Al. In citrate buffer, Al did not decrease in spite of the high elution amount. Considering that the solubility profile of aluminum oxide and the Al eluting profile of borosilicate glass were different, it is speculated that Al ion may be forced to leach into the buffer solution according to Si elution on the surface of glass vials. When Al ions were added to the buffer solutions, phosphate, acetate and histidine buffer showed a decrease of Al concentration during storage at a neutral range of pHs, indicating the formation of particles containing Al. In conclusion, it is suggested that phosphate buffer solution has higher possibility of forming particles containing Al than other buffer solutions.

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

    PubMed

    Riesová, Martina; Svobodová, Jana; Tošner, Zdeněk; Beneš, Martin; Tesařová, Eva; Gaš, Bohuslav

    2013-09-17

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

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

    PubMed

    Riesová, Martina; Svobodová, Jana; Tošner, Zdeněk; Beneš, Martin; Tesařová, Eva; Gaš, Bohuslav

    2013-09-17

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

  12. INFLUENCE OF ORGANIC BUFFERS ON BACTERIOCIN PRODUCTION BY STREPTOCOCCUS THERMOPHILUS ST110

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of the organic buffer salts MES, MOPS and PIPES on the growth of S. thermophilus ST110, medium pH and accumulation of the antipediococcal bacteriocin thermophilin 110 were evaluated in whey permeate media over a period of 24 h. In non buffered medium, thermophilin 110 production at 37°C ...

  13. Preparation of vinyl acetate

    DOEpatents

    Tustin, Gerald Charles; Zoeller, Joseph Robert; Depew, Leslie Sharon

    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.

  14. Preparation of vinyl acetate

    DOEpatents

    Tustin, G.C.; Zoeller, J.R.; Depew, L.S.

    1998-03-24

    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.

  15. Sphingolipids contribute to acetic acid resistance in Zygosaccharomyces bailii.

    PubMed

    Lindahl, Lina; Genheden, Samuel; Eriksson, Leif A; Olsson, Lisbeth; Bettiga, Maurizio

    2016-04-01

    Lignocellulosic raw material plays a crucial role in the development of sustainable processes for the production of fuels and chemicals. Weak acids such as acetic acid and formic acid are troublesome inhibitors restricting efficient microbial conversion of the biomass to desired products. To improve our understanding of weak acid inhibition and to identify engineering strategies to reduce acetic acid toxicity, the highly acetic-acid-tolerant yeast Zygosaccharomyces bailii was studied. The impact of acetic acid membrane permeability on acetic acid tolerance in Z. bailii was investigated with particular focus on how the previously demonstrated high sphingolipid content in the plasma membrane influences acetic acid tolerance and membrane permeability. Through molecular dynamics simulations, we concluded that membranes with a high content of sphingolipids are thicker and more dense, increasing the free energy barrier for the permeation of acetic acid through the membrane. Z. bailii cultured with the drug myriocin, known to decrease cellular sphingo-lipid levels, exhibited significant growth inhibition in the presence of acetic acid, while growth in medium without acetic acid was unaffected by the myriocin addition. Furthermore, following an acetic acid pulse, the intracellular pH decreased more in myriocin-treated cells than in control cells. This indicates a higher inflow rate of acetic acid and confirms that the reduction in growth of cells cultured with myriocin in the medium with acetic acid was due to an increase in membrane permeability, thereby demonstrating the importance of a high fraction of sphingolipids in the membrane of Z. bailii to facilitate acetic acid resistance; a property potentially transferable to desired production organisms suffering from weak acid stress. PMID:26416641

  16. Sphingolipids contribute to acetic acid resistance in Zygosaccharomyces bailii.

    PubMed

    Lindahl, Lina; Genheden, Samuel; Eriksson, Leif A; Olsson, Lisbeth; Bettiga, Maurizio

    2016-04-01

    Lignocellulosic raw material plays a crucial role in the development of sustainable processes for the production of fuels and chemicals. Weak acids such as acetic acid and formic acid are troublesome inhibitors restricting efficient microbial conversion of the biomass to desired products. To improve our understanding of weak acid inhibition and to identify engineering strategies to reduce acetic acid toxicity, the highly acetic-acid-tolerant yeast Zygosaccharomyces bailii was studied. The impact of acetic acid membrane permeability on acetic acid tolerance in Z. bailii was investigated with particular focus on how the previously demonstrated high sphingolipid content in the plasma membrane influences acetic acid tolerance and membrane permeability. Through molecular dynamics simulations, we concluded that membranes with a high content of sphingolipids are thicker and more dense, increasing the free energy barrier for the permeation of acetic acid through the membrane. Z. bailii cultured with the drug myriocin, known to decrease cellular sphingo-lipid levels, exhibited significant growth inhibition in the presence of acetic acid, while growth in medium without acetic acid was unaffected by the myriocin addition. Furthermore, following an acetic acid pulse, the intracellular pH decreased more in myriocin-treated cells than in control cells. This indicates a higher inflow rate of acetic acid and confirms that the reduction in growth of cells cultured with myriocin in the medium with acetic acid was due to an increase in membrane permeability, thereby demonstrating the importance of a high fraction of sphingolipids in the membrane of Z. bailii to facilitate acetic acid resistance; a property potentially transferable to desired production organisms suffering from weak acid stress.

  17. Comparative evaluation of tensile bond strength of a polyvinyl acetate-based resilient liner following various denture base surface pre-treatment methods and immersion in artificial salivary medium: An in vitro study

    PubMed Central

    Philip, Jacob M.; Ganapathy, Dhanraj M.; Ariga, Padma

    2012-01-01

    Background and Aim: This study was formulated to evaluate and estimate the influence of various denture base resin surface pre-treatments (chemical and mechanical and combinations) upon tensile bond strength between a poly vinyl acetate-based denture liner and a denture base resin. Materials and Methods: A universal testing machine was used for determining the bond strength of the liner to surface pre-treated acrylic resin blocks. The data was analyzed by one-way analysis of variance and the t-test (α =.05). Results: This study infers that denture base surface pre-treatment can improve the adhesive tensile bond strength between the liner and denture base specimens. The results of this study infer that chemical, mechanical, and mechano-chemical pre-treatments will have different effects on the bond strength of the acrylic soft resilient liner to the denture base. Conclusion: Among the various methods of pre-treatment of denture base resins, it was inferred that the mechano-chemical pre-treatment method with air-borne particle abrasion followed by monomer application exhibited superior bond strength than other methods with the resilient liner. Hence, this method could be effectively used to improve bond strength between liner and denture base and thus could minimize delamination of liner from the denture base during function. PMID:23293485

  18. Adaptation and tolerance of bacteria against acetic acid.

    PubMed

    Trček, 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

  19. Sphingolipids contribute to acetic acid resistance in Zygosaccharomyces bailii

    PubMed Central

    Lindahl, Lina; Genheden, Samuel; Eriksson, Leif A.; Olsson, Lisbeth

    2015-01-01

    ABSTRACT Lignocellulosic raw material plays a crucial role in the development of sustainable processes for the production of fuels and chemicals. Weak acids such as acetic acid and formic acid are troublesome inhibitors restricting efficient microbial conversion of the biomass to desired products. To improve our understanding of weak acid inhibition and to identify engineering strategies to reduce acetic acid toxicity, the highly acetic‐acid‐tolerant yeast Zygosaccharomyces bailii was studied. The impact of acetic acid membrane permeability on acetic acid tolerance in Z. bailii was investigated with particular focus on how the previously demonstrated high sphingolipid content in the plasma membrane influences acetic acid tolerance and membrane permeability. Through molecular dynamics simulations, we concluded that membranes with a high content of sphingolipids are thicker and more dense, increasing the free energy barrier for the permeation of acetic acid through the membrane. Z. bailii cultured with the drug myriocin, known to decrease cellular sphingo­lipid levels, exhibited significant growth inhibition in the presence of acetic acid, while growth in medium without acetic acid was unaffected by the myriocin addition. Furthermore, following an acetic acid pulse, the intracellular pH decreased more in myriocin‐treated cells than in control cells. This indicates a higher inflow rate of acetic acid and confirms that the reduction in growth of cells cultured with myriocin in the medium with acetic acid was due to an increase in membrane permeability, thereby demonstrating the importance of a high fraction of sphingolipids in the membrane of Z. bailii to facilitate acetic acid resistance; a property potentially transferable to desired production organisms suffering from weak acid stress. Biotechnol. Bioeng. 2016;113: 744–753. © 2015 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. PMID:26416641

  20. 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.

  1. Development of a simple, low-cost and eurytopic medium based on Pleurotus eryngii for lactic acid bacteria.

    PubMed

    Zhao, Yancun; Wang, Ying; Song, Zhiwei; Shan, Chengjun; Zhu, Runjie; Liu, Fengquan

    2016-12-01

    Lactic acid bacteria (LAB) are a group of important beneficial microorganisms for human, but their growth is restricted to the habitats with rich nutrients. In order to develop a simple, low-cost and efficient medium based on the mushroom Pleurotus eryngii, this study evaluated the effects of different treatment methods for the mushroom, concentration of the mushroom, buffers, tween 80, MgSO4·7H2O, MnSO4·4H2O, CuSO4·5H2O, riboflavin and ascorbic acid on the growth of Lactococcus lactis subsp. lactis SLPE1-3. An optimized medium was developed, which was composed of the mushroom at 200 g/L, the buffer sodium acetate at 5 g/L, and riboflavin at 0.5 mg/L. The mushroom was ground, boiled and filtered for the filtrate in advance. In this optimized medium which was named as PSR medium, the population density of SLPE1-3 sharply reached 2.13 × 10(9) CFU/mL within 18 h of incubation, and still maintained 1.17 × 10(8) CFU/mL at 120 h. In addition, this study found that 6 kinds of LAB could grow almost well, and maintained high survival in PSR medium compared to M17 or MRS medium, including Lactococcus lactis subsp. lactis, Lactobacillus plantarum, Lactococcus lactis subsp. cremoris, Lactobacillus paracasei, Pediococcus pentosaceus and Lactobacillus rhamnosus. These results showed that PSR medium was a simple, low cost and eurytopic medium for the cultivation of LAB, and could replace MRS or M17 medium in the food industry, biomedicine and laboratory. PMID:27590888

  2. Acetate as Sole Carbon and Energy Source for Growth of Methanosarcina Strain 227

    PubMed Central

    Smith, Michael R.; Mah, Robert A.

    1980-01-01

    Methanosarcina strain 227 grew rapidly and produced methane on a mineral medium containing acetate as the sole added organic substrate. Cell yields but not doubling times were affected by the presence or absence of yeast extract. Greater cell yields occurred in yeast extract medium than in mineral medium. Radioactive labeling studies showed that acetate was decarboxylated in mineral medium, as was shown previously in complex medium. The specific radioactivity of methane produced per specific acitvity of acetate added was not significantly different in yeast extract medium compared with mineral medium. Unequivocal evidence indicates that the cleavage of acetate to methane and carbon dioxide provided the energy for growth in the presence or absence of other organic compounds; these latter compounds do not serve as energy sources, electron donors, or significant sources of methane during this aceticlastic reaction. PMID:16345576

  3. Virtual Frame Buffer Interface Program

    NASA Technical Reports Server (NTRS)

    Wolfe, Thomas L.

    1990-01-01

    Virtual Frame Buffer Interface program makes all frame buffers appear as generic frame buffer with specified set of characteristics, allowing programmers to write codes that run unmodified on all supported hardware. Converts generic commands to actual device commands. Consists of definition of capabilities and FORTRAN subroutines called by application programs. Developed in FORTRAN 77 for DEC VAX 11/780 or DEC VAX 11/750 computer under VMS 4.X.

  4. Critical evaluation of buffering solutions for pKa determination by capillary electrophoresis.

    PubMed

    Fuguet, Elisabet; Reta, Mario; Gibert, Carme; Rosés, Martí; Bosch, Elisabeth; Ràfols, Clara

    2008-07-01

    The performance of the most common and also some other less common CE buffers has been tested for the pKa determination of several types of compounds (pyridine, amines, and phenols). The selected buffers cover a pH ranging from 3.7 to 11.8. Whereas some buffers, like acetic acid/acetate, BisTrisH+/BisTris, TrisH+/Tris, CHES/CHES-, and CAPS/CAPS- can be used with all type of analytes, others like ammonium/ammonia, butylammonium/butylammonia, ethylammonium/ethylammonia, diethylammonium/diethylammonia, and hydrogenphosphate/phosphate are not recommended because they interact with a wide range of compounds. The rest of the tested buffers (dihydrogenphosphate/hydrogenphosphate, MES/MES-, HEPES/HEPES-, and boric acid/borate) can show specific interactions depending on the nature of the analytes, and their use in some applications should be restricted.

  5. Methane from acetate.

    PubMed

    Ferry, J G

    1992-09-01

    The general features are known for the pathway by which most methane is produced in nature. All acetate-utilizing methanogenic microorganisms contain CODH which catalyzes the cleavage of acetyl-CoA; however, the pathway differs from all other acetate-utilizing anaerobes in that the methyl group is reduced to methane with electrons derived from oxidation of the carbonyl group of acetyl-CoA to CO2. The current understanding of the methanogenic fermentation of acetate provides impressions of nature's novel solutions to problems of methyl transfer, electron transport, and energy conservation. The pathway is now at a level of understanding that will permit productive investigations of these and other interesting questions in the near future. PMID:1512186

  6. Delineation of myocardial oxygen utilization with carbon-11-labeled acetate

    SciTech Connect

    Brown, M.; Marshall, D.R.; Sobel, B.E.; Bergmann, S.R.

    1987-09-01

    Although positron-emission tomography (PET) with labeled fatty acid delineates infarct size and permits qualitative assessment of fatty acid utilization, quantification of oxidative metabolism is limited by complex alterations in the pattern of utilization of fatty acid during ischemia and reperfusion. Because metabolism of acetate by myocardium is less complex than that of glucose or palmitate, we characterized kinetics of utilization of radiolabeled acetate in 37 isolated rabbit hearts perfused with modified Krebs-Henseleit buffer and performed a pilot tomographic study in man. Results of initial experiments with carbon-14-labeled acetate (/sup 14/C-acetate) indicated that the steady-state extraction fraction of acetate averaged 61.5 +/- 4.0% in control hearts (n = 4), 93.6 +/- 0.9% in hearts rendered ischemic (n = 4), and 54.8 +/- 4.0% in hearts reperfused after 60 min of ischemia (n = 3). Oxidation of /sup 14/C-acetate, assessed from the rate of efflux of /sup 14/CO/sub 2/ in the venous effluent, correlated closely with the rate of oxygen consumption under diverse metabolic conditions (r = .97, p less than .001). In addition, no significant differences were observed between rates of efflux of total /sup 14/C in all chemical species (reflecting total clearance of tracer from myocardium) and efflux of /sup 14/CO/sub 2/. Clearance of /sup 11/C-acetate, measured externally with gamma probes in normal and ischemic myocardium, correlated closely with clearance of /sup 14/C-acetate measured directly in the effluent (r = .99, p less than .001) and with overall myocardial oxygen consumption (r = .95, p less than .001). Accumulation and clearance of /sup 11/C-acetate from human myocardium with PET demonstrated kinetics comparable to those seen with radiolabeled acetate in vitro.

  7. Efficient reduction of the formation of by-products and improvement of production yield of 2,3-butanediol by a combined deletion of alcohol dehydrogenase, acetate kinase-phosphotransacetylase, and lactate dehydrogenase genes in metabolically engineered Klebsiella oxytoca in mineral salts medium.

    PubMed

    Jantama, Kaemwich; Polyiam, Pattharasedthi; Khunnonkwao, Panwana; Chan, Sitha; Sangproo, Maytawadee; Khor, Kirin; Jantama, Sirima Suvarnakuta; Kanchanatawee, Sunthorn

    2015-07-01

    Klebsiella oxytoca KMS005 (∆adhE∆ackA-pta∆ldhA) was metabolically engineered to improve 2,3-butanediol (BDO) yield. Elimination of alcohol dehydrogenase E (adhE), acetate kinase A-phosphotransacetylase (ackA-pta), and lactate dehydrogenase A (ldhA) enzymes allowed BDO production as a primary pathway for NADH re-oxidation, and significantly reduced by-products. KMS005 was screened for the efficient glucose utilization by metabolic evolution. KMS005-73T improved BDO production at a concentration of 23.5±0.5 g/L with yield of 0.46±0.02 g/g in mineral salts medium containing 50 g/L glucose in a shake flask. KMS005-73T also exhibited BDO yields of about 0.40-0.42 g/g from sugarcane molasses, cassava starch, and maltodextrin. During fed-batch fermentation, KMS005-73T produced BDO at a concentration, yield, and overall and specific productivities of 117.4±4.5 g/L, 0.49±0.02 g/g, 1.20±0.05 g/Lh, and 27.2±1.1 g/gCDW, respectively. No acetoin, lactate, and formate were detected, and only trace amounts of acetate and ethanol were formed. The strain also produced the least by-products and the highest BDO yield among other Klebsiella strains previously developed. PMID:25895450

  8. Acetate utilization and macromolecular synthesis during sporulation of yeast.

    PubMed

    Esposito, M S; Esposito, R E; Arnaud, M; Halvorson, H O

    1969-10-01

    Acetate utilization and macromolecule synthesis during sporulation (meiosis) of Saccharomyces cerevisiae were studied. When diploid cells are transferred from glucose nutrient medium to acetate sporulation medium at early stationary phase, respiration of the exogenously supplied acetate proceeds without any apparent lag. At the completion of ascospore development, 62% of the acetate carbon consumed has been respired, 22% remains in the soluble pool, and 16% is incorporated into lipids, protein, nucleic acids, and other cell components. Measurements of the rate of protein synthesis during sporulation reveal two periods of maximal synthetic activity: an early phase coincidental with increases in deoxyribonucleic acid, ribonucleic acid, and protein cellular content and a later phase during ascospore formation. Experiments in which protein synthesis was inhibited at intervals during sporulation indicate that protein synthesis is required both for the initiation and completion of ascus development.

  9. 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.

  10. Ring Buffered Network Bus

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This report describes the research effort to demonstrate the integration of a data sharing technology, Ring Buffered Network Bus, in development by Dryden Flight Research Center, with an engine simulation application, the Java Gas Turbine Simulator, in development at the University of Toledo under a grant from the Glenn Research Center. The objective of this task was to examine the application of the RBNB technologies as a key component in the data sharing, health monitoring and system wide modeling elements of the NASA Aviation Safety Program (AVSP) [Golding, 1997]. System-wide monitoring and modeling of aircraft and air safety systems will require access to all data sources which are relative factors when monitoring or modeling the national airspace such as radar, weather, aircraft performance, engine performance, schedule and planning, airport configuration, flight operations, etc. The data sharing portion of the overall AVSP program is responsible for providing the hardware and software architecture to access and distribute data, including real-time flight operations data, among all of the AVSP elements. The integration of an engine code capable of numerically "flying" through recorded flight paths and weather data using a software tool that allows for distributed access of data to this engine code demonstrates initial steps toward building a system capable of monitoring and modeling the National Airspace.

  11. Mechanisms of buffer therapy resistance.

    PubMed

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

    2014-04-01

    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.

  12. 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.

  13. Clostridiumm ljungdahlii, an anaerobic ethanol and acetate producing microorganism

    DOEpatents

    Gaddy, James L.; Clausen, Edgar C.

    1992-01-01

    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.

  14. Viscometric study of chitosan solutions in acetic acid/sodium acetate and acetic acid/sodium chloride.

    PubMed

    Costa, Cristiane N; Teixeira, Viviane G; Delpech, Marcia C; Souza, Josefa Virginia S; Costa, Marcos A S

    2015-11-20

    A viscometric study was carried out at 25°C to assess the physical-chemical behavior in solution and the mean viscometric molar mass (M¯v) of chitosan solutions with different deacetylation degrees, in two solvent mixtures: medium 1-acetic acid 0.3mol/L and sodium acetate 0.2mol/L; and medium 2-acetic acid 0.1mol/L and sodium chloride 0.2mol/L. Different equations were employed, by graphical extrapolation, to calculate the intrinsic viscosities [η] and the viscometric constants, to reveal the solvent's quality: Huggins (H), Kraemer (K) and Schulz-Blaschke (SB). For single-point determination, the equations used were SB, Solomon-Ciuta (SC) and Deb-Chanterjee (DC), resulting in a faster form of analysis. The values of ̄M¯v were calculated by applying the equation of Mark-Houwink-Sakurada. The SB and SC equations were most suitable for single-point determination of [η] and ̄M¯v and the Schulz-Blachke constant (kSB), equal to 0.28, already utilized for various systems, can also be employed to analyze chitosan solutions under the conditions studied.

  15. Influence of different buffers (HEPES/MOPS) on keratinocyte cell viability and microbial growth.

    PubMed

    Dias, Kássia de Carvalho; Barbugli, Paula Aboud; Vergani, Carlos Eduardo

    2016-06-01

    This study assessed the effect of the buffers 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) and 3-(N-morpholino) propanesulfonic acid (MOPS) on keratinocyte cell viability and microbial growth. It was observed that RPMI buffered with HEPES, supplemented with l-glutamine and sodium bicarbonate, can be used as a more suitable medium to promote co-culture. PMID:27060444

  16. Extractive fermentation of acetic acid

    SciTech Connect

    Busche, R.M.

    1991-12-31

    In this technoeconomic evaluation of the manufacture of acetic acid by fermentation, the use of the bacterium: Acetobacter suboxydans from the old vinegar process was compared with expected performance of the newer Clostridium thermoaceticum bacterium. Both systems were projected to operate as immobilized cells in a continuous, fluidized bed bioreactor, using solvent extraction to recover the product. Acetobacter metabolizes ethanol aerobically to produce acid at 100 g/L in a low pH medium. This ensures that the product is in the form of a concentrated extractable free acid, rather than as an unextractable salt. Unfortunately, yields from glucose by way of the ethanol fermentation are poor, but near the biological limits of the organisms involved. Conversely, C. thermoaceticum is a thermophilic anaerobe that operates at high fermentation rates on glucose at neutral pH to produce acetate salts directly in substantially quantitative yields. However, it is severely inhibited by product, which restricts concentration to a dilute 20 g/L. An improved Acetobacter system operating with recycled cells at 50 g/L appears capable of producing acid at $0.38/lb, as compared with a $0.29/lb price for synthetic acid. However, this system has only a limited margin for process improvement. The present Clostridium system cannot compete, since the required selling price would be $0.42/lb. However, if the organism could be adapted to tolerate higher product concentrations at acid pH, selling price could be reduced to $0.22/lb, or about 80% of the price of synthetic acid.

  17. Rapid demineralization in acidic buffers.

    PubMed

    Eggert, F M; Germain, J P

    1979-01-22

    The demineralization of routine histological specimens in buffers of weakly ionized organic acids, unbuffered formic acid, and EDTA was investigated. The rate of demineralization was measured by a chemical method and from radiographs. Lactate-containing buffers and buffers of formic acid with its potassium salt were more rapid in effect than any other agent. Acidic buffers and unbuffered formic acid produced rapid diffuse demineralization with secondary precipitation of calcium salts. Preservation of dental enamel in such buffers resulted from the significantly slower rate of enamel demineralization than that for bone and dentine. In rapid demineralizing agents the secondary salts were quickly redissolved while in slow buffers these salts persisted. Multivalent ions such as citrate and maleate slowed the rate of demineralization, and a citrate-containing buffer was the slowest of all the agents tested. Demineralization in EDTA exhibited a different pattern with the establishment of a well-defined front of demineralization without apparent reprecipitation. EDTA attacked enamel, bone and dentine at the same rate. An attempt was made to relate the observed rates of demineralization to current theories of the demineralization process.

  18. Electrodialysis operation with buffer solution

    DOEpatents

    Hryn, John N.; Daniels, Edward J.; Krumdick, Greg K.

    2009-12-15

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

  19. Acetate Production by Methanogenic Bacteria

    PubMed Central

    Westermann, Peter; Ahring, Birgitte K.; Mah, Robert A.

    1989-01-01

    Methanosarcina barkeri MS and 227 and Methanosarcina mazei S-6 produced acetate when grown on H2-CO2, methanol, or trimethylamine. Marked differences in acetate production by the two bacterial species were found, even though methane and cell yields were nearly the same. M. barkeri produced 30 to 75 μmol of acetate per mmol of CH4 formed, but M. mazei produced only 8 to 9 μmol of acetate per mmol of CH4. PMID:16348006

  20. INFLUENCE OF GROWTH MEDIUM ON ASSIMILATORY ACTIVITIES OF ESCHERICHIA COLI

    PubMed Central

    Clifton, C. E.

    1963-01-01

    Clifton, C. E. (Stanford University, Stanford, Calif.). Influence of growth medium on assimilatory activities of Escherichia coli. J. Bacteriol. 85:1371–1377. 1963.—Nutrient agargrown cells assimilate about 50% of the glucose added to washed suspensions (phosphate buffer, pH 7.2, 30 C), as indicated by O2 consumption or C14-uptake from uniformly labeled glucose. Most of the nonassimilated glucose is oxidized, but a small portion remains in forms other than glucose in the suspension medium. Cells from glucose agar, however, assimilate only about 20 to 30% of the U-glucose and ferment a considerable portion of the remainder, the extent of each being determined in part at least by growth conditions. Evidence is presented that this behavior is the result of metabolic controls induced during growth. C14 from U-glucose appeared in all fractions of either agar- or glucose agar-grown cells, the highest percentage being present in cellular matter insoluble in hot 5% trichloroacetic acid. Data on the distribution of C14 from 1-, 2-, and 6-glucose, and from acetate and pyruvate, are also presented. PMID:14047232

  1. Acetate dependence of tumors.

    PubMed

    Comerford, Sarah A; Huang, Zhiguang; Du, Xinlin; Wang, Yun; Cai, Ling; Witkiewicz, Agnes K; Walters, Holly; Tantawy, Mohammed N; Fu, Allie; Manning, H Charles; Horton, Jay D; Hammer, Robert E; McKnight, Steven L; Tu, Benjamin P

    2014-12-18

    Acetyl-CoA represents a central node of carbon metabolism that plays a key role in bioenergetics, cell proliferation, and the regulation of gene expression. Highly glycolytic or hypoxic tumors must produce sufficient quantities of this metabolite to support cell growth and survival under nutrient-limiting conditions. Here, we show that the nucleocytosolic acetyl-CoA synthetase enzyme, ACSS2, supplies a key source of acetyl-CoA for tumors by capturing acetate as a carbon source. Despite exhibiting no gross deficits in growth or development, adult mice lacking ACSS2 exhibit a significant reduction in tumor burden in two different models of hepatocellular carcinoma. ACSS2 is expressed in a large proportion of human tumors, and its activity is responsible for the majority of cellular acetate uptake into both lipids and histones. These observations may qualify ACSS2 as a targetable metabolic vulnerability of a wide spectrum of tumors.

  2. 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.

  3. Free flow cell electrophoresis using zwitterionic buffer

    NASA Technical Reports Server (NTRS)

    Rodkey, R. Scott

    1990-01-01

    Studies of a zwitterionic buffer formulated for cell electrophoresis were done using the McDonnell-Douglas Continuous Flow Electrophoresis System. Standard buffers were analyzed for their stability in the electrical field and the results showed that both buffers tested were inherently unstable. Further, titration studies showed that the standards buffers buffered poorly at the pH employed for electrophoresis. The zwitterionic buffer buffered well at its nominal pH and was shown to be stable in the electrical field. Comparative studies of the buffer with standard cell separation buffers using formalin fixed rabbit and goose red blood cells showed that the zwitterionic buffer gave better resolution of the fixed cells. Studies with viable hybridoma cells showed that buffer Q supported cell viability equal to Hank's Balanced Salt Solution and that hybridoma cells in different stages of the growth cycle demonstrated reproducible differences in electrophoretic mobility.

  4. Redox responses in yeast to acetate as the carbon source.

    PubMed

    Minard, Karyl I; McAlister-Henn, L

    2009-03-01

    Following a shift to medium with acetate as the carbon source, a parental yeast strain exhibited a transient moderate 20% reduction in total cellular [NAD(+)+NADH] but showed a approximately 10-fold increase in the ratio of [NAD(+)]:[NADH] after 36h. A mutant strain (idhDelta) lacking the tricarboxylic acid cycle enzyme isocitrate dehydrogenase had 50% higher cellular levels of [NAD(+)+NADH] relative to the parental strain but exhibited similar changes in cofactor concentrations following a shift to acetate medium, despite an inability to grow on that carbon source; essentially all of the cofactor was in the oxidized form within 36h. The salvage pathway for NAD(H) biosynthesis was found to be particularly important for viability during early transition of the parental strain to stationary phase in acetate medium. However, oxygen consumption was not affected, suggesting that the NAD(H) produced during this time may support other cellular functions. The idhDelta mutant exhibited increased flux through the salvage pathway in acetate medium but was dependent on the de novo pathway for viability. Long-term chronological lifespans of the parental and idhDelta strains were similar, but viability of the mutant strain was dependent on both pathways for NAD(H) biosynthesis.

  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.

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

    PubMed

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

    1999-11-01

    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 simple, selective, precise and suitable for the determination of octreotide acetate in admixture.

  7. Buffer Effects in the Solubility, Nucleation and Growth of Chicken Egg White Lysozyme

    NASA Technical Reports Server (NTRS)

    Gibson, Ursula J.

    1999-01-01

    The growth of protein crystals is important for determination of their three-dimensional structure, which relates to their biochemical functions and to the practical goal of designing pharmaceuticals to modify that function. While many proteins have been successfully crystallized by a variety of methods, there is still limited understanding of the process of nucleation and growth of even the simplest proteins. Chicken egg-white lysozyme (CEWL) is readily crystallized under a variety of conditions, and studies underway at MSFC are designed to elucidate the mechanisms by which the crystals nucleate and grow. We have investigated the effect of buffer choice on the solubility, nucleation and growth of CEWL. CEWL was purified by dialysis against a .05M phosphate buffer and chromatographic separation from contaminants in a sepharose column. Solubility studies were made as a function of buffer concentration for phosphate and formate buffers, and the nucleation and growth of crystals at 10 C was studied as a function of pH for oxalate, succinate, formate, butyrate, carbonate, phosphate and acetate buffer solutions. The solubility data support the conclusion that there is a solubility minimum as a function of buffer concentration for amphiphilic molecules, while no minimum is observed for a phosphate buffer. Nucleation is suppressed at pH greater than pKa for all buffers except phosphate. The aspect ratio of the (110) faces is shown to be a function of crystal size, rather than pH.

  8. Beneficial Effect of Acetic Acid on the Xylose Utilization and Bacterial Cellulose Production by Gluconacetobacter xylinus.

    PubMed

    Yang, Xiao-Yan; Huang, Chao; Guo, Hai-Jun; Xiong, Lian; Luo, Jun; Wang, Bo; Chen, Xue-Fang; Lin, Xiao-Qing; Chen, Xin-De

    2014-09-01

    In this work, acetic acid was found as one promising substrate to improve xylose utilization by Gluconacetobacter xylinus CH001. Also, with the help of adding acetic acid into medium, the bacterial cellulose (BC) production by G. xylinus was increased significantly. In the medium containing 3 g l(-1) acetic acid, the optimal xylose concentration for BC production was 20 g l(-1). In the medium containing 20 g l(-1) xylose, the xylose utilization and BC production by G. xylinus were stimulated by acetic acid within certain concentration. The highest BC yield (1.35 ± 0.06 g l(-1)) was obtained in the medium containing 20 g l(-1) xylose and 3 g l(-1) acetic acid after 14 days. This value was 6.17-fold higher than the yield (0.21 ± 0.01 g l(-1)) in the medium only containing 20 g l(-1) xylose. The results analyzed by FE-SEM, FTIR, and XRD showed that acetic acid affected little on the microscopic morphology and physicochemical characteristics of BC. Base on the phenomenon observed, lignocellulosic acid hydrolysates (xylose and acetic acid are main carbon sources present in it) could be considered as one potential substrate for BC production.

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

    NASA Astrophysics Data System (ADS)

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

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

  10. Buffering New Information during Reading.

    ERIC Educational Resources Information Center

    Haberlandt, Karl; Graesser, Arthur C.

    1989-01-01

    Describes two subject-paced reading experiments in which word-reading times were collected using the moving-window method. Finds that reading times of content words increase more steeply than reading times for function words. Discusses results in terms of buffer models of reading, the processing of different lexical classes, and hypotheses which…

  11. Buffering in cyclic gene networks

    NASA Astrophysics Data System (ADS)

    Glyzin, S. D.; Kolesov, A. Yu.; Rozov, N. Kh.

    2016-06-01

    We consider cyclic chains of unidirectionally coupled delay differential-difference equations that are mathematical models of artificial oscillating gene networks. We establish that the buffering phenomenon is realized in these system for an appropriate choice of the parameters: any given finite number of stable periodic motions of a special type, the so-called traveling waves, coexist.

  12. Bi-directional ACET micropump for on-chip biological applications.

    PubMed

    Vafaie, Reza Hadjiaghaie; Ghavifekr, Habib Badri; Van Lintel, Harald; Brugger, Juergen; Renaud, Philippe

    2016-03-01

    The ability to control and pump high ionic strength fluids inside microchannels forms a major advantage for clinical diagnostics and drug screening processes, where high conductive biological and physiological buffers are used. Despite the known potential of AC electro-thermal (ACET) effect in different biomedical applications, comparatively little is known about controlling the velocity and direction of fluid inside the chip. Here, we proposed to discretize the conventional electrodes to form various asymmetric electrode structures in order to control the fluid direction by simple switching the appropriate electric potential applied to the discretized electrodes. The ACET pumping effect was numerically studied by solving electrical, thermal and hydrodynamic multi-physic coupled equations to optimize the geometrical dimensions of the discretized system. PBS solutions with different ionic strength were seeded with 1 μm sized fluorescent particles and electrothermally driven fluid motion was observed inside the channel for different electrode structures. Experimental analyses confirm that the proposed micropump is efficient for a conductivity range between 0.1 and 1 S/m and the efficiency improves by increasing the voltage amplitude. Behavior of the proposed electrode-electrolyte system is discussed by lumped circuit model. Frequency response of system illustrated that the optimal frequency range increases by increasing the conductivity of medium. For 0.18 S/m PBS solution, the constant pumping effect was observed at frequency range between 100 kHz and 1 MHz, while frequency range of 100 kHz to 5 MHZ was observed for 0.42 S/m. The characteristics of experimental results were in good agreement with the theoretical model. PMID:26790840

  13. Comparison of growth, acetate production, and acetate inhibition of Escherichia coli strains in batch and fed-batch fermentations.

    PubMed Central

    Luli, G W; Strohl, W R

    1990-01-01

    The growth characteristics and acetate production of several Escherichia coli strains were compared by using shake flasks, batch fermentations, and glucose-feedback-controlled fed-batch fermentations to assess the potential of each strain to grow at high cell densities. Of the E. coli strains tested, including JM105, B, W3110, W3100, HB101, DH1, CSH50, MC1060, JRG1046, and JRG1061, strains JM105 and B were found to have the greatest relative biomass accumulation, strain MC1060 accumulated the highest concentrations of acetic acid, and strain B had the highest growth rates under the conditions tested. In glucose-feedback-controlled fed-batch fermentations, strains B and JM105 produced only 2 g of acetate.liter-1 while accumulating up to 30 g of biomass.liter-1. Under identical conditions, strains HB101 and MC1060 accumulated less than 10 g of biomass.liter-1 and strain MC1060 produced 8 g of acetate.liter-1. The addition of various concentrations of sodium acetate to the growth medium resulted in a logarithmic decrease, with respect to acetate concentration, in the growth rates of E. coli JM105, JM105(pOS4201), and JRG1061. These data indicated that the growth of the E. coli strains was likely to be inhibited by the acetate they produced when grown on media containing glucose. A model for the inhibition of growth of E. coli by acetate was derived from these experiments to explain the inhibition of acetate on E. coli strains at neutral pH. PMID:2187400

  14. Comparison of growth, acetate production, and acetate inhibition of Escherichia coli strains in batch and fed-batch fermentations.

    PubMed

    Luli, G W; Strohl, W R

    1990-04-01

    The growth characteristics and acetate production of several Escherichia coli strains were compared by using shake flasks, batch fermentations, and glucose-feedback-controlled fed-batch fermentations to assess the potential of each strain to grow at high cell densities. Of the E. coli strains tested, including JM105, B, W3110, W3100, HB101, DH1, CSH50, MC1060, JRG1046, and JRG1061, strains JM105 and B were found to have the greatest relative biomass accumulation, strain MC1060 accumulated the highest concentrations of acetic acid, and strain B had the highest growth rates under the conditions tested. In glucose-feedback-controlled fed-batch fermentations, strains B and JM105 produced only 2 g of acetate.liter-1 while accumulating up to 30 g of biomass.liter-1. Under identical conditions, strains HB101 and MC1060 accumulated less than 10 g of biomass.liter-1 and strain MC1060 produced 8 g of acetate.liter-1. The addition of various concentrations of sodium acetate to the growth medium resulted in a logarithmic decrease, with respect to acetate concentration, in the growth rates of E. coli JM105, JM105(pOS4201), and JRG1061. These data indicated that the growth of the E. coli strains was likely to be inhibited by the acetate they produced when grown on media containing glucose. A model for the inhibition of growth of E. coli by acetate was derived from these experiments to explain the inhibition of acetate on E. coli strains at neutral pH. PMID:2187400

  15. Quantum magnetic deflagration in acetate.

    PubMed

    Hernández-Mínguez, A; Hernandez, J M; Macià, F; García-Santiago, A; Tejada, J; Santos, P V

    2005-11-18

    We report controlled ignition of magnetization reversal avalanches by surface acoustic waves in a single crystal of acetate. Our data show that the speed of the avalanche exhibits maxima on the magnetic field at the tunneling resonances of Mn(12). Combined with the evidence of magnetic deflagration in Mn(12) acetate, this suggests a novel physical phenomenon: deflagration assisted by quantum tunneling. PMID:16384178

  16. Quantum magnetic deflagration in acetate.

    PubMed

    Hernández-Mínguez, A; Hernandez, J M; Macià, F; García-Santiago, A; Tejada, J; Santos, P V

    2005-11-18

    We report controlled ignition of magnetization reversal avalanches by surface acoustic waves in a single crystal of acetate. Our data show that the speed of the avalanche exhibits maxima on the magnetic field at the tunneling resonances of Mn(12). Combined with the evidence of magnetic deflagration in Mn(12) acetate, this suggests a novel physical phenomenon: deflagration assisted by quantum tunneling.

  17. Vacuum ultraviolet and infrared spectra of condensed methyl acetate on cold astrochemical dust analogs

    SciTech Connect

    Sivaraman, B.; Nair, B. G.; Mason, N. J.; Lo, J.-I.; Cheng, B.-M.; Kundu, S.; Davis, D.; Prabhudesai, V.; Krishnakumar, E.; Raja Sekhar, B. N.

    2013-12-01

    Following the recent report of the first identification of methyl acetate (CH{sub 3}COOCH{sub 3}) in the interstellar medium (ISM), we have carried out vacuum ultraviolet (VUV) and infrared (IR) spectroscopy studies on methyl acetate from 10 K until sublimation in an ultrahigh vacuum chamber simulating astrochemical conditions. We present the first VUV and IR spectra of methyl acetate relevant to ISM conditions. Spectral signatures clearly showed molecular reorientation to have started in the ice by annealing the amorphous ice formed at 10 K. An irreversible phase change from amorphous to crystalline methyl acetate ice was found to occur between 110 K and 120 K.

  18. Matching phosphate and maleate buffer systems for dissolution of weak acids: Equivalence in terms of buffer capacity of bulk solution or surface pH?

    PubMed

    Cristofoletti, Rodrigo; Dressman, Jennifer B

    2016-06-01

    The development of in vitro dissolution tests able to anticipate the in vivo fate of drug products has challenged pharmaceutical scientists over time, especially in the case of ionizable compounds. In the seminal model proposed by Mooney et al. thirty-five years ago, the pH at the solid-liquid interface (pH0) was identified as a key parameter in predicting dissolution rate. In the current work it is demonstrated that the in vitro dissolution of the weak acid ibuprofen in maleate and phosphate buffer systems is a function of the pH0, which in turn is affected by properties of the drug and the medium. The reported pH0 for ibuprofen dissolution in bicarbonate buffer, the predominant buffer species in the human small intestine under fasting conditions, can be achieved by reducing the phosphate buffer concentration to 5.0mM or the maleate buffer concentration to 2.2mM. Using this approach to identify the appropriate buffer/buffer capacity combination for in vitro experiments in FaSSIF-type media, it would be possible to increase the physiological relevance of this important biopharmaceutics tool. However, the necessity of monitoring and adjusting the bulk pH during the experiments carried out in 5.0mM phosphate or 2.2mM maleate buffers must also be taken into consideration. PMID:27032508

  19. Matching phosphate and maleate buffer systems for dissolution of weak acids: Equivalence in terms of buffer capacity of bulk solution or surface pH?

    PubMed

    Cristofoletti, Rodrigo; Dressman, Jennifer B

    2016-06-01

    The development of in vitro dissolution tests able to anticipate the in vivo fate of drug products has challenged pharmaceutical scientists over time, especially in the case of ionizable compounds. In the seminal model proposed by Mooney et al. thirty-five years ago, the pH at the solid-liquid interface (pH0) was identified as a key parameter in predicting dissolution rate. In the current work it is demonstrated that the in vitro dissolution of the weak acid ibuprofen in maleate and phosphate buffer systems is a function of the pH0, which in turn is affected by properties of the drug and the medium. The reported pH0 for ibuprofen dissolution in bicarbonate buffer, the predominant buffer species in the human small intestine under fasting conditions, can be achieved by reducing the phosphate buffer concentration to 5.0mM or the maleate buffer concentration to 2.2mM. Using this approach to identify the appropriate buffer/buffer capacity combination for in vitro experiments in FaSSIF-type media, it would be possible to increase the physiological relevance of this important biopharmaceutics tool. However, the necessity of monitoring and adjusting the bulk pH during the experiments carried out in 5.0mM phosphate or 2.2mM maleate buffers must also be taken into consideration.

  20. Aqueous stability of leuprolide acetate: effect of temperature, dissolved oxygen, pH and complexation with β-cyclodextrin.

    PubMed

    Rahimi, Mehdi; Mobedi, Hamid; Behnamghader, Aliasghar

    2016-01-01

    In the present research, the aqueous stability of leuprolide acetate (LA) in phosphate buffered saline (PBS) medium was studied (pH = 2.0-7.4). For this purpose, the effect of temperature, dissolved oxygen and pH on the stability of LA during 35 days was investigated. Results showed that the aqueous stability of LA was higher at low temperatures. Degassing of the PBS medium partially increased the stability of LA at 4 °C, while did not change at 37 °C. The degradation of LA was accelerated at lower pH values. In addition, complexes of LA with different portions of β-cyclodextrin (β-CD) were prepared through freeze-drying procedure and characterized by Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC) analyses. Studying their aqueous stability at various pH values (2.0-7.4) showed LA/β-CD complexes exhibited higher stability when compared with LA at all pH values. The stability of complexes was also improved by increasing the portion of LA/β-CD up to 1/10.

  1. Cell buffer with built-in test

    NASA Technical Reports Server (NTRS)

    Ott, William E. (Inventor)

    2004-01-01

    A cell buffer with built-in testing mechanism is provided. The cell buffer provides the ability to measure voltage provided by a power cell. The testing mechanism provides the ability to test whether the cell buffer is functioning properly and thus providing an accurate voltage measurement. The testing mechanism includes a test signal-provider to provide a test signal to the cell buffer. During normal operation, the test signal is disabled and the cell buffer operates normally. During testing, the test signal is enabled and changes the output of the cell buffer in a defined way. The change in the cell buffer output can then be monitored to determine if the cell buffer is functioning correctly. Specifically, if the voltage output of the cell buffer changes in a way that corresponds to the provided test signal, then the functioning of the cell buffer is confirmed. If the voltage output of the cell buffer does not change correctly, then the cell buffer is known not to be operating correctly. Thus, the built in testing mechanism provides the ability to quickly and accurately determine if the cell buffer is operating correctly. Furthermore, the testing mechanism provides this functionality without requiring excessive device size and complexity.

  2. The influence of the nature of background anions on the buffer capacity of glycine-containing electrolytes for nickel electroplating

    NASA Astrophysics Data System (ADS)

    Dolgikh, O. V.; Zuen, Vu Tkhi; Sotskaya, N. V.

    2009-06-01

    The buffer properties of acetate, sulfate, and chloride glycine-containing electrolytes for nickel electroplating were studied. Various forms of the amino acid and background anions were shown to act in solution as two buffer systems related by competitive complex formation. The buffer capacity of a solution was then the result of the joint action of these systems. The contribution of each of them was determined by its absolute concentration in solution on the one hand and changes in this concentration caused by the addition of H+ or OH- ions on the other.

  3. Laser velocimeter (autocovariance) buffer interface

    NASA Technical Reports Server (NTRS)

    Clemmons, J. I., Jr.

    1981-01-01

    A laser velocimeter (autocovariance) buffer interface (LVABI) was developed to serve as the interface between three laser velocimeter high speed burst counters and a minicomputer. A functional description is presented of the instrument and its unique features which allow the studies of flow velocity vector analysis, turbulence power spectra, and conditional sampling of other phenomena. Typical applications of the laser velocimeter using the LVABI are presented to illustrate its various capabilities.

  4. Operation of static and flowing Cs DPAL with different buffer gas mixtures

    NASA Astrophysics Data System (ADS)

    Knize, R. J.; Zhdanov, B. V.; Rotondaro, M. T.; Shaffer, M. K.

    2016-03-01

    Cs DPAL operation using Ethane, Methane and mixtures of these hydrocarbons with noble gases He and Ar as a buffer gases for spin-orbit relaxation was studied in this work. The best Cs DPAL performance in continuous wave operation with flowing gain medium was achieved using pure Methane, pure Ethane or a mixture of Ethane (minimum of 200 Torr) and He with a total buffer gas pressure of 300 torr.

  5. RESEARCH NEEDS IN RIPARIAN BUFFER RESTORATION

    EPA Science Inventory

    Riparian buffer restorations are used as management tools to produce favorable water quality impacts; moreover, the basis for riparian buffers as an instrument of water quality restoration rests on a relatively firm foundation. However, the extent to which buffers can restore rip...

  6. Doped LZO buffer layers for laminated conductors

    DOEpatents

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

    2010-03-23

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

  7. [Postoperative refractory chylothorax which was improved by octreotide acetate].

    PubMed

    Gabe, Atsushi; Seki, Masahiro; Taira, Naohiro; Katsura, Morihiro; Ishida, Tomoki; Kang, Yukijya; Kubota, Tadao; Yamashiro, Toshimitsu; Uehara, Tetsuo; Sunagawa, Tohru; Ohkubo, Kazuaki

    2012-03-01

    A 77-year-old male with chronic hepatitis and liver cirrhosis underwent a right middle-lower lobectomy and lymph node dissection because of non-small cell carcinoma of the lung. On the 1st post-operative day (POD1), a large quantity of chylous pleural effusion was recognized after he initiated oral intake. The diagnosis was postoperative chylothorax. Conservative therapy including a medium chain tryglyceride diet and total parental nutrition were not effective. Considering of the patient's past history, we decided to continue conservative therapy using octreotide acetate on POD7. After administration of the octreotide acetate, the volume of chylous pleural effusion gradually decreased. The chest tube was removed on POD19. Octeotide acetate should be a choice for the conservative treatment of postoperative refractory chylothorax.

  8. Buffering Capacity and Membrane H+ Conductance of Neutrophilic and Alkalophilic Gram-Positive Bacteria

    PubMed Central

    Rius, Núria; Lorén, José G.

    1998-01-01

    Buffering capacity and membrane H+ conductance were examined in three gram-positive bacteria, Staphylococcus aureus, Bacillus subtilis, and Bacillus alcalophilus. An acid pulse technique was used to measure both parameters. The buffering capacity and membrane H+ conductance of B. alcalophilus are influenced by the pH of the medium and the culture conditions. Suspensions of B. alcalophilus cells from both H. A. medium and l-malate medium cultures grown at pH 10.5 exhibited higher values for these parameters than cells grown at pH 8.5. B. alcalophilus grown aerobically had a lower buffering capacity and a lower membrane conductance for protons than the neutrophilic bacteria S. aureus and B. subtilis. Fermenting cells exhibited significantly higher values for both variables than respiring cells. PMID:9546171

  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. 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

  11. 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.

  12. Retention of ionisable compounds on high-performance liquid chromatography XVII. Estimation of the pH variation of aqueous buffers with the change of the methanol fraction of the mobile phase.

    PubMed

    Subirats, Xavier; Bosch, Elisabeth; Rosés, Martí

    2007-01-01

    The use of methanol-aqueous buffer mobile phases in HPLC is a common election when performing chromatographic separations of ionisable analytes. The addition of methanol to the aqueous buffer to prepare such a mobile phase changes the buffer capacity and the pH of the solution. In the present work, the variation of these buffer properties is studied for acetic acid-acetate, phosphoric acid-dihydrogenphosphate-hydrogenphosphate, citric acid-dihydrogencitrate-hydrogencitrate-citrate, and ammonium-ammonia buffers. It is well established that the pH change of the buffers depends on the initial concentration and aqueous pH of the buffer, on the percentage of methanol added, and on the particular buffer used. The proposed equations allow the pH estimation of methanol-water buffered mobile phases up to 80% in volume of organic modifier from initial aqueous buffer pH and buffer concentration (before adding methanol) between 0.001 and 0.01 mol L(-1). From both the estimated pH values of the mobile phase and the estimated pKa of the ionisable analytes, it is possible to predict the degree of ionisation of the analytes and therefore, the interpretation of acid-base analytes behaviour in a particular methanol-water buffered mobile phase.

  13. Buffered Communication Analysis in Distributed Multiparty Sessions

    NASA Astrophysics Data System (ADS)

    Deniélou, Pierre-Malo; Yoshida, Nobuko

    Many communication-centred systems today rely on asynchronous messaging among distributed peers to make efficient use of parallel execution and resource access. With such asynchrony, the communication buffers can happen to grow inconsiderately over time. This paper proposes a static verification methodology based on multiparty session types which can efficiently compute the upper bounds on buffer sizes. Our analysis relies on a uniform causality audit of the entire collaboration pattern - an examination that is not always possible from each end-point type. We extend this method to design algorithms that allocate communication channels in order to optimise the memory requirements of session executions. From these analyses, we propose two refinements methods which respect buffer bounds: a global protocol refinement that automatically inserts confirmation messages to guarantee stipulated buffer sizes and a local protocol refinement to optimise asynchronous messaging without buffer overflow. Finally our work is applied to overcome a buffer overflow problem of the multi-buffering algorithm.

  14. Acetate-mediated growth inhibition in sterol 14alpha-demethylation-deficient cells of Candida albicans.

    PubMed

    Shimokawa, O; Nakayama, H

    1999-01-01

    Candida albicans is a fungus thought to be viable in the presence of a deficiency in sterol 14alpha-demethylation. We showed in a strain of this species that the deficiency, caused either by a mutation or by an azole antifungal agent, made the cells susceptible to growth inhibition by acetate included in the culture medium. Studies with a mutant demonstrated that the inhibition was complete at a sodium acetate concentration of 0.24 M (20 g/liter) and was evident even at a pH of 8, the latter result indicating the involvement of acetate ions rather than the undissociated form of acetic acid. In fluconazole-treated cells, sterol profiles determined by thin-layer chromatography revealed that the minimum sterol 14alpha-demethylation-inhibitory concentrations (MDICs) of the drug, thought to be the most important parameter for clinical purposes, were practically identical in the media with and without 0.24 M acetate and were equivalent to the MIC in the acetate-supplemented medium. The acetate-mediated growth inhibition of azole-treated cells was confirmed with two additional strains of C. albicans and four different agents, suggesting the possibility of generalization. From these results, it was surmised that the acetate-containing medium may find use in azole susceptibility testing, for which there is currently no method capable of measuring MDICs directly for those fungi whose viability is not lost as a result of sterol 14alpha-demethylation deficiency. Additionally, the acetate-supplemented agar medium was found to be useful in detecting reversions from sterol 14alpha-demethylation deficiency to proficiency. PMID:9869573

  15. Retention of ionisable compounds on high-performance liquid chromatography XIX. pH variation in mobile phases containing formic acid, piperazine and tris as buffering systems and methanol as organic modifier.

    PubMed

    Subirats, Xavier; Bosch, Elisabeth; Rosés, Martí

    2009-07-10

    In previous works a model to estimate the pH of methanol-aqueous buffer mobile phases from the aqueous pH and concentration of the buffer and the fraction of organic modifier was developed. This model was successfully applied and validated for buffers prepared from ammonia, acetic, phosphoric and citric acids. In the present communication this model has been extended to formic acid, piperazine and tris(hydroxymethyl)aminomethane buffers. Prior to the modelling work, the pK(a) values of the studied buffers at several methanol-water compositions were determined.

  16. Buffered Electrochemical Polishing of Niobium

    SciTech Connect

    Gianluigi Ciovati; Tian, Hui; Corcoran, Sean

    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 (? 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.

  17. Role of the glyoxylate pathway in acetic acid production by Acetobacter aceti.

    PubMed

    Sakurai, Kenta; Yamazaki, Shoko; Ishii, Masaharu; Igarashi, Yasuo; Arai, Hiroyuki

    2013-01-01

    Wild-type Acetobacter aceti NBRC 14818 possesses genes encoding isocitrate lyase (aceA) and malate synthase (glcB), which constitute the glyoxylate pathway. In contrast, several acetic acid bacteria that are utilized for vinegar production lack these genes. Here, an aceA-glcB knockout mutant of NBRC 14818 was constructed and used for investigating the role of the glyoxylate pathway in acetate productivity. In medium containing ethanol as a carbon source, the mutant grew normally during ethanol oxidation to acetate, but exhibited slower growth than that of the wild-type strain as the accumulated acetate was oxidized. The mutant grew similarly to that of the wild-type strain in medium containing glucose as a carbon source, indicating that the glyoxylate pathway was not necessary for glucose utilization. However, in medium containing both ethanol and glucose, the mutant exhibited significantly poorer growth and lower glucose consumption compared to the wild-type strain. Notably, the mutant oxidized ethanol nearly stoichiometrically to acetate, which was retained in the medium for a longer period of time than the acetate produced by wild-type strain. The features of the aceA-glcB knockout mutant revealed here indicate that the lack of the glyoxylate pathway is advantageous for industrial vinegar production by A. aceti.

  18. Focusing Light Beams To Improve Atomic-Vapor Optical Buffers

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry; Matsko, Andrey; Savchenkov, Anatoliy

    2010-01-01

    Specially designed focusing of light beams has been proposed as a means of improving the performances of optical buffers based on cells containing hot atomic vapors (e.g., rubidium vapor). There is also a companion proposal to improve performance by use of incoherent optical pumping under suitable conditions. Regarding the proposal to use focusing: The utility of atomic-vapor optical buffers as optical storage and processing devices has been severely limited by nonuniform spatial distributions of intensity in optical beams, arising from absorption of the beams as they propagate in atomic-vapor cells. Such nonuniformity makes it impossible to optimize the physical conditions throughout a cell, thereby making it impossible to optimize the performance of the cell as an optical buffer. In practical terms simplified for the sake of brevity, "to optimize" as used here means to design the cell so as to maximize the group delay of an optical pulse while keeping the absorption and distortion of the pulse reasonably small. Regarding the proposal to use incoherent optical pumping: For reasons too complex to describe here, residual absorption of light is one of the main impediments to achievement of desirably long group delays in hot atomic vapors. The present proposal is directed toward suppressing residual absorption of light. The idea of improving the performance of slow-light optical buffers by use of incoherent pumping overlaps somewhat with the basic idea of Raman-based slow-light systems. However, prior studies of those systems did not quantitatively answer the question of whether the performance of an atomic vapor or other medium that exhibits electromagnetically induced transparency (EIT) with Raman gain is superior to that of a medium that exhibits EIT without Raman gain.

  19. Biophysical stability of hyFc fusion protein with regards to buffers and various excipients.

    PubMed

    Lim, Jun Yeul; Kim, Nam Ah; Lim, Dae Gon; Eun, Chang-yong; Choi, Donghoon; Jeong, Seong Hoon

    2016-05-01

    A novel non-cytolytic hybrid Fc (hyFc) with an intact Ig structure without any mutation in the hyFc region, was developed to construct a long-acting agonistic protein. The stability of interleukin-7 (IL-7) fused with the hyFc (GXN-04) was evaluated to develop early formulations. Various biophysical methods were utilized and three different buffer systems with various pH ranges were investigated including histidine-acetate, sodium citrate, and tris buffers. Various excipients were incorporated into the systems to obtain optimum protein stability. Two evident thermal transitions were observed with the unfolding of IL-7 and hyFc. The Tm and ΔH increased with pH, suggesting increased conformational stability. Increased Z-average size with PDI and decreased zeta potential with pH increase, with the exception of tris buffer, showed aggregation issues. Moreover, tris buffer at higher pH showed aggregation peaks from DLS. Non-ionic surfactants were effective against agitation by outcompeting protein molecules for hydrophobic surfaces. Sucrose and sorbitol accelerated protein aggregation during agitation, but exhibited a protective effect against oxidation, with preferential exclusion favoring the compact states of GXN-04. The stability of GXN-04 was varied by basal buffers and excipients, hence the buffers and excipients need to be evaluated carefully to achieve the maximum stability of proteins. PMID:26851357

  20. 21 CFR 173.228 - Ethyl acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the specifications of the Food Chemicals Codex, 1 (Ethyl Acetate; p. 372, 3d Ed., 1981), which are... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ethyl acetate. 173.228 Section 173.228 Food and..., Lubricants, Release Agents and Related Substances § 173.228 Ethyl acetate. Ethyl acetate (CAS Reg. No....

  1. 21 CFR 173.228 - Ethyl acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the specifications of the Food Chemicals Codex, 1 (Ethyl Acetate; p. 372, 3d Ed., 1981), which are... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethyl acetate. 173.228 Section 173.228 Food and..., Lubricants, Release Agents and Related Substances § 173.228 Ethyl acetate. Ethyl acetate (CAS Reg. No....

  2. 21 CFR 73.2396 - Lead acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Lead acetate. 73.2396 Section 73.2396 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a) Identity. The color additive lead acetate is the trihydrate of lead (2+) salt of acetic acid. The color additive has the chemical formula...

  3. 21 CFR 73.2396 - Lead acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Lead acetate. 73.2396 Section 73.2396 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a) Identity. The color additive lead acetate is the trihydrate of lead (2+) salt of acetic acid. The color additive has the chemical formula...

  4. 21 CFR 73.2396 - Lead acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Lead acetate. 73.2396 Section 73.2396 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a) Identity. The color additive lead acetate is the trihydrate of lead (2+) salt of acetic acid. The color additive has the chemical formula...

  5. 21 CFR 73.2396 - Lead acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Lead acetate. 73.2396 Section 73.2396 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a) Identity. The color additive lead acetate is the trihydrate of lead (2+) salt of acetic acid. The color additive has the chemical formula...

  6. 21 CFR 73.2396 - Lead acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Lead acetate. 73.2396 Section 73.2396 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a) Identity. The color additive lead acetate is the trihydrate of lead (2+) salt of acetic acid. The color additive has the chemical formula...

  7. O-Allylation of phenols with allylic acetates in aqueous media using a magnetically separable catalytic system

    EPA Science Inventory

    Allylic ethers were synthesized in water using magnetically recoverable heterogeneous Pd catalyst via O-allylation of phenols with allylic acetates under ambient conditions. Aqueous reaction medium, easy recovery of the catalyst using an external magnet, efficient recycling, and ...

  8. New aspects on the preparation of [11C]acetate--a simple and fast approach via distillation.

    PubMed

    Mitterhauser, Markus; Wadsak, Wolfgang; Krcal, Andreas; Schmaljohann, Joern; Bartosch, Ewald; Eidherr, Harald; Viernstein, Helmut; Kletter, Kurt

    2004-12-01

    [11C]Acetate, initially developed for nuclear cardiology has gained increased interest also for oncological problems. A conjoint problem of all preparation methods is the high sensitivity of the Grignard-precursor to moisture, demanding long cleaning and drying procedures of apparatus and reaction vials. Our rationale was to simplify and accelerate the preparation of [11C]acetate by the development of an inert, sterile and disposable system. The present publication deals with the remote-controlled preparation of [11C]acetate via distillation into a buffer ready to use.

  9. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium acetate. 184.1185 Section 184.1185 Food... GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by...

  10. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium acetate. 184.1185 Section 184.1185 Food and... Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may...

  11. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium acetate. 184.1185 Section 184.1185 Food... Specific Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid....

  12. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium acetate. 184.1185 Section 184.1185 Food... Specific Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid....

  13. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium acetate. 184.1185 Section 184.1185 Food... Specific Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid....

  14. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... acetate, 2-methoxyethanol, and 2-methoxyethanol acetate. 721.10001 Section 721.10001 Protection of...-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate. (a) Chemical substances and significant...-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and...

  15. 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

  16. Buffer strips in composites at elevated temperature

    NASA Technical Reports Server (NTRS)

    Bigelow, C. A.

    1983-01-01

    The composite material 'buffer strip' concept is presently investigated at elevated temperatures for the case of graphite/polyimide buffer strip panels using a (45/0/45/90)2S layup, where the buffer strip material was 0-deg S-glass/polyimide. Each panel was loaded in tension until it failed, and radiographs and crack opening displacements were recorded during the tests to determine fracture onset, fracture arrest, and the extent of damage in the buffer strip after crack arrest. At 177 + or - 3 C, the buffer strips increased the panel strength by at least 40 percent in comparison with panels without buffer strips. Compared to similar panels tested at room temperature, those tested at elevated temperature had lower residual strengths, but higher failure strains.

  17. Analysis of proteins responsive to acetic acid in Acetobacter: molecular mechanisms conferring acetic acid resistance in acetic acid bacteria.

    PubMed

    Nakano, Shigeru; Fukaya, Masahiro

    2008-06-30

    Acetic acid bacteria are used for industrial vinegar production because of their remarkable ability to oxidize ethanol and high resistance to acetic acid. Although several molecular machineries responsible for acetic acid resistance in acetic acid bacteria have been reported, the entire mechanism that confers acetic acid resistance has not been completely understood. One of the promising methods to elucidate the entire mechanism is global analysis of proteins responsive to acetic acid by two-dimensional gel electrophoresis. Recently, two proteins whose production was greatly enhanced by acetic acid in Acetobacter aceti were identified to be aconitase and a putative ABC-transporter, respectively; furthermore, overexpression or disruption of the genes encoding these proteins affected acetic acid resistance in A. aceti, indicating that these proteins are involved in acetic acid resistance. Overexpression of each gene increased acetic acid resistance in Acetobacter, which resulted in an improvement in the productivity of acetic acid fermentation. Taken together, the results of the proteomic analysis and those of previous studies indicate that acetic acid resistance in acetic acid bacteria is conferred by several mechanisms. These findings also provide a clue to breed a strain having high resistance to acetic acid for vinegar fermentation.

  18. WFC3 SS Science Data Buffer Test

    NASA Astrophysics Data System (ADS)

    MacKenty, John

    2012-10-01

    Part of side switch activities.The WFC3 Science Buffer RAM is checked for bit flips during SAA passages. This is followed by a Control Section {CS} self-test consisting of writing/reading a specified bit pattern from each memory location in Buffer RAM. The CS Buffer RAM self-test as well as the bit flip tests are all done with the CS in OPERATE.ID:WF03

  19. Signature-based store checking buffer

    DOEpatents

    Sridharan, Vilas; Gurumurthi, Sudhanva

    2015-06-02

    A system and method for optimizing redundant output verification, are provided. A hardware-based store fingerprint buffer receives multiple instances of output from multiple instances of computation. The store fingerprint buffer generates a signature from the content included in the multiple instances of output. When a barrier is reached, the store fingerprint buffer uses the signature to verify the content is error-free.

  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. Cadmium resistance screening in nitrilotriacetate-buffered minimal media. [Rhizobium fredii

    SciTech Connect

    Angle, J.S. ); Chaney, R.L. )

    1989-08-01

    Media used to determine the MICs of heavy metals for bacteria are unreliable because organic components in the media bind or chelate most of the metal being studied. To define specific metal activity in media and to maintain metal activity at a constant level, HEPES-MES (N-2-hydroxyethylpiperazine-N{prime}-2-ethanesulfonic acid-2-(N-morpholine)ethanesulfonic acid) salts medium with arabinose medium was modified, and the modified medium was used to examine the MIC of cadmium for Rhizobium fredii USDA 201. Arabinose-HEPES-MES was modified by addition of the chelator nitrilotriacetate to buffer the supply of free Cd{sup 2+} ion to maintain a constant Cd activity and by the use of only MES to buffer pH (buffered arabinose-MES medium (BAM)). Ca and Mg were supplied at the normal levels for soil solutions, and other trace elements were supplied at the levels required for normal growth of plants. The concentration of free Cd{sup 2+} ion was calculated by using the computer program GEOCHEM-PC with a corrected data base. The Cd MIC in BAM was 14.0 {mu}M, while that in a tryptone-yeast extract medium was 107 {mu}M. The results indicate that substantial free Cd{sup 2+} is removed from solution in most standard media, resulting in falsely high MICs. The new BAM medium allows for the precise determination of MICs, thus avoiding the uncertainties associated with other media.

  3. Cell Electrosensitization Exists Only in Certain Electroporation Buffers

    PubMed Central

    Dermol, Janja; Pakhomova, Olga N.; Pakhomov, Andrei G.; Miklavčič, Damijan

    2016-01-01

    Electroporation-induced cell sensitization was described as the occurrence of a delayed hypersensitivity to electric pulses caused by pretreating cells with electric pulses. It was achieved by increasing the duration of the electroporation treatment at the same cumulative energy input. It could be exploited in electroporation-based treatments such as electrochemotherapy and tissue ablation with irreversible electroporation. The mechanisms responsible for cell sensitization, however, have not yet been identified. We investigated cell sensitization dynamics in five different electroporation buffers. We split a pulse train into two trains varying the delay between them and measured the propidium uptake by fluorescence microscopy. By fitting the first-order model to the experimental results, we determined the uptake due to each train (i.e. the first and the second) and the corresponding resealing constant. Cell sensitization was observed in the growth medium but not in other tested buffers. The effect of pulse repetition frequency, cell size change, cytoskeleton disruption and calcium influx do not adequately explain cell sensitization. Based on our results, we can conclude that cell sensitization is a sum of several processes and is buffer dependent. Further research is needed to determine its generality and to identify underlying mechanisms. PMID:27454174

  4. Cell Electrosensitization Exists Only in Certain Electroporation Buffers.

    PubMed

    Dermol, Janja; Pakhomova, Olga N; Pakhomov, Andrei G; Miklavčič, Damijan

    2016-01-01

    Electroporation-induced cell sensitization was described as the occurrence of a delayed hypersensitivity to electric pulses caused by pretreating cells with electric pulses. It was achieved by increasing the duration of the electroporation treatment at the same cumulative energy input. It could be exploited in electroporation-based treatments such as electrochemotherapy and tissue ablation with irreversible electroporation. The mechanisms responsible for cell sensitization, however, have not yet been identified. We investigated cell sensitization dynamics in five different electroporation buffers. We split a pulse train into two trains varying the delay between them and measured the propidium uptake by fluorescence microscopy. By fitting the first-order model to the experimental results, we determined the uptake due to each train (i.e. the first and the second) and the corresponding resealing constant. Cell sensitization was observed in the growth medium but not in other tested buffers. The effect of pulse repetition frequency, cell size change, cytoskeleton disruption and calcium influx do not adequately explain cell sensitization. Based on our results, we can conclude that cell sensitization is a sum of several processes and is buffer dependent. Further research is needed to determine its generality and to identify underlying mechanisms. PMID:27454174

  5. Reductive opening of carbohydrate phenylsulfonylethylidene (PSE) acetals.

    PubMed

    Chéry, Florence; Cabianca, Elena; Tatibouët, Arnaud; De Lucchi, Ottorino; Lindhorst, Thisbe K; Rollin, Patrick

    2015-11-19

    The phenylsulfonylethylidene (PSE) acetal is a relatively new protecting group in carbohydrate chemistry. However, carbohydrate-derived phenylsulfonylethylidene (PSE) acetals show a different behavior in reductive desulfonylation than simple symmetrical acetals. Here we have investigated various SET-type reaction conditions in order to open PSE acetals regioselectively and to produce chiral ω-hydroxyethenyl ethers. Whereas sodium amalgam leads to a mixture of regioisomeric vinyl ethers besides the ethylidene acetal, samarium iodide is suited for regioselective ring opening. This is shown with seven different carbohydrate PSE acetals, both of the 1,3-dioxane and the 1,3-dioxolane type. PMID:26469209

  6. Genome-wide identification of Saccharomyces cerevisiae genes required for tolerance to acetic acid

    PubMed Central

    2010-01-01

    Background Acetic acid is a byproduct of Saccharomyces cerevisiae alcoholic fermentation. Together with high concentrations of ethanol and other toxic metabolites, acetic acid may contribute to fermentation arrest and reduced ethanol productivity. This weak acid is also a present in lignocellulosic hydrolysates, a highly interesting non-feedstock substrate in industrial biotechnology. Therefore, the better understanding of the molecular mechanisms underlying S. cerevisiae tolerance to acetic acid is essential for the rational selection of optimal fermentation conditions and the engineering of more robust industrial strains to be used in processes in which yeast is explored as cell factory. Results The yeast genes conferring protection against acetic acid were identified in this study at a genome-wide scale, based on the screening of the EUROSCARF haploid mutant collection for susceptibility phenotypes to this weak acid (concentrations in the range 70-110 mM, at pH 4.5). Approximately 650 determinants of tolerance to acetic acid were identified. Clustering of these acetic acid-resistance genes based on their biological function indicated an enrichment of genes involved in transcription, internal pH homeostasis, carbohydrate metabolism, cell wall assembly, biogenesis of mitochondria, ribosome and vacuole, and in the sensing, signalling and uptake of various nutrients in particular iron, potassium, glucose and amino acids. A correlation between increased resistance to acetic acid and the level of potassium in the growth medium was found. The activation of the Snf1p signalling pathway, involved in yeast response to glucose starvation, is demonstrated to occur in response to acetic acid stress but no evidence was obtained supporting the acetic acid-induced inhibition of glucose uptake. Conclusions Approximately 490 of the 650 determinants of tolerance to acetic acid identified in this work are implicated, for the first time, in tolerance to this weak acid. These are

  7. A kinetic study of isoamyl acetate synthesis by immobilized lipase-catalyzed acetylation in n-hexane.

    PubMed

    Romero, M D; Calvo, L; Alba, C; Daneshfar, A

    2007-01-01

    The objective of this work was to propose a reaction mechanism and to develop a rate equation for the synthesis of isoamyl acetate by acylation of the corresponding alcohol with acetic anhydride using the lipase Novozym 435 in n-hexane. The reaction between isoamyl alcohol and acetic anhydride occurred at high rate in first place. Then, if excess alcohol was used, produced acetic acid further reacted with remaining alcohol, leading to yields higher than 100% (based on initial acetic anhydride content). This reaction was much slower and took place only when acetic anhydride had been totally consumed. Optimal pH for Novozym 435 was 7.7. Acetic acid strongly inactivated the enzyme but it was partially caused by the pH drop in the biocatalyst aqueous microenvironment. Acetic anhydride also showed an important inhibition effect. On the contrary, isoamyl alcohol and isoamyl acetate had no negative effect on the lipase. The analysis of the initial rate data showed that reaction followed a Ping-Pong Bi-Bi mechanism with inhibition by acetic anhydride. The kinetic constants were obtained by multiple regression analysis of experimental findings. Equation predictions and experimental reaction rate values matched very well at conditions where acetic acid concentration in the medium was low.

  8. High stability buffered phase comparator

    NASA Technical Reports Server (NTRS)

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

    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.

  9. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine...

  10. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine...

  11. Supramolecular buffering by ring-chain competition.

    PubMed

    Paffen, Tim F E; Ercolani, Gianfranco; de Greef, Tom F A; Meijer, E W

    2015-02-01

    Recently, we reported an organocatalytic system in which buffering of the molecular catalyst by supramolecular interactions results in a robust system displaying concentration-independent catalytic activity. Here, we demonstrate the design principles of the supramolecular buffering by ring-chain competition using a combined experimental and theoretical approach. Our analysis shows that supramolecular buffering of a molecule is caused by its participation as a chain stopper in supramolecular ring-chain equilibria, and we reveal here the influence of various thermodynamic parameters. Model predictions based on independently measured equilibrium constants corroborate experimental data of several molecular systems in which buffering occurs via competition between cyclization, growth of linear chains, and end-capping by the chain-stopper. Our analysis reveals that the effective molarity is the critical parameter in optimizing the broadness of the concentration regime in which supramolecular ring-chain buffering occurs as well as the maximum concentration of the buffered molecule. To conclude, a side-by-side comparison of supramolecular ring-chain buffering, pH buffering, and molecular titration is presented.

  12. Riparian buffer transpiration and watershed scale impacts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forested riparian buffers are prevalent throughout the Southeastern Coastal Plain Region of the United States (US). Because they make up a significant portion of the regional landscape, transpiration within these riparian buffers is believed to have an important impact on the hydrologic budget of r...

  13. The buffer capacity of airway epithelial secretions

    PubMed Central

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

    2014-01-01

    The pH of airway epithelial secretions influences bacterial killing and mucus properties and is reduced by acidic pollutants, gastric reflux, and respiratory diseases such as cystic fibrosis (CF). The effect of acute acid loads depends on buffer capacity, however the buffering of airway secretions has not been well characterized. In this work we develop a method for titrating micro-scale (30 μl) volumes and use it to study fluid secreted by the human airway epithelial cell line Calu-3, a widely used model for submucosal gland serous cells. Microtitration curves revealed that HCO−3 is the major buffer. Peak buffer capacity (β) increased from 17 to 28 mM/pH during forskolin stimulation, and was reduced by >50% in fluid secreted by cystic fibrosis transmembrane conductance regulator (CFTR)-deficient Calu-3 monolayers, confirming an important role of CFTR in HCO−3 secretion. Back-titration with NaOH revealed non-volatile buffer capacity due to proteins synthesized and released by the epithelial cells. Lysozyme and mucin concentrations were too low to buffer Calu-3 fluid significantly, however model titrations of porcine gastric mucins at concentrations near the sol-gel transition suggest that mucins may contribute to the buffer capacity of ASL in vivo. We conclude that CFTR-dependent HCO−3 secretion and epithelially-derived proteins are the predominant buffers in Calu-3 secretions. PMID:24917822

  14. Field effect transistors improve buffer amplifier

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Unity gain buffer amplifier with a Field Effect Transistor /FET/ differential input stage responds much faster than bipolar transistors when operated at low current levels. The circuit uses a dual FET in a unity gain buffer amplifier having extremely high input impedance, low bias current requirements, and wide bandwidth.

  15. FIFO Buffer for Asynchronous Data Streams

    NASA Technical Reports Server (NTRS)

    Bascle, K. P.

    1985-01-01

    Variable-rate, asynchronous data signals from up to four measuring instruments or other sources combined in first-in/first-out (FIFO) buffer for transmission on single channel. Constructed in complementary metal-oxide-semiconductor (CMOS) logic, buffer consumes low power (only 125 mW at 5V) and conforms to aerospace standards of reliability and maintainability.

  16. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes...

  17. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes...

  18. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes...

  19. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes...

  20. Buffer Management Simulation in ATM Networks

    NASA Technical Reports Server (NTRS)

    Yaprak, E.; Xiao, Y.; Chronopoulos, A.; Chow, E.; Anneberg, L.

    1998-01-01

    This paper presents a simulation of a new dynamic buffer allocation management scheme in ATM networks. To achieve this objective, an algorithm that detects congestion and updates the dynamic buffer allocation scheme was developed for the OPNET simulation package via the creation of a new ATM module.

  1. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes...

  2. African American College Women's Suicide Buffers.

    ERIC Educational Resources Information Center

    Marion, Michelle S.; Range, Lillian M.

    2003-01-01

    To examine the relationships buffers may have with suicide ideation, 300 African American female college students completed measures of suicide ideation and buffers. Three variables accounted for a significant and unique portion of the variance in suicide ideation: family support, a view that suicide is unacceptable, and a collaborative religious…

  3. 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...

  4. Optimization of protein buffer cocktails using Thermofluor.

    PubMed

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

    2013-02-01

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

  5. Migration behaviour of discontinuous buffers in capillary electrophoresis during protein enrichment.

    PubMed

    Li, Ting; Booker, Christina J; Yeung, Ken K-C

    2012-10-21

    Capillary electrophoresis (CE) is not only an effective separation technique, but can also serve as a sample preparation tool for enrichment and purification at sub-microliter sample volumes. Our approach is based on the use of a discontinuous buffer system consisting of an acid and a base (acetate and ammonium). Proteins and/or peptides with isoelectric points between the pH values of these two buffers will become stacked at the neutralization reaction boundary (NRB). To understand the mechanism of the NRB formation and the electrophoretic migration of various ions during the enrichment, we performed experiments using myoglobin and mesityl oxide to reveal the ion migration patterns at the buffer junction, and utilized Simul 5 to computer simulate the process. The simulated results closely resembled the experimental data, and together, they effectively revealed the characteristics of the discontinuous buffers. Importantly, the discovery allowed the manipulation of NRB behaviours by controlling the discontinuous buffer composition. To illustrate this, the removal of urea as an unwanted background molecule from the enriched protein sample was achieved based on the acquired information.

  6. Carbon-isotopic analysis of dissolved acetate

    NASA Technical Reports Server (NTRS)

    Gelwicks, J. T.; Hayes, J. M.

    1990-01-01

    Heating of dried, acetate-containing solids together with oxalic acid dihydrate conveniently releases acetic acid for purification by gas chromatography. For determination of the carbon-isotopic composition of total acetate, the acetate-containing zone of the chromatographic effluent can be routed directly to a combustion furnace coupled to a vacuum system allowing recovery, purification, and packaging of CO2 for mass-spectrometric analysis. For analysis of methyl carbon, acetic acid can be cryogenically trapped from the chromatographic effluent, then transferred to a tube containing excess NaOH. The tube is evacuated, sealed, and heated to 500 degrees C to produce methane by pyrolysis of sodium acetate. Subsequent combustion of the methane allows determination of the 13C content at the methyl position in the parent acetate. With typical blanks, the standard deviation of single analyses is less than 0.4% for acetate samples larger than 5 micromoles. A full treatment of uncertainties is outlined.

  7. 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.

  8. Enhanced expression of aconitase raises acetic acid resistance in Acetobacter aceti.

    PubMed

    Nakano, Shigeru; Fukaya, Masahiro; Horinouchi, Sueharu

    2004-06-15

    Acetobacter spp. are used for industrial vinegar production because of their high ability to oxidize ethanol to acetic acid and high resistance to acetic acid. Two-dimensional gel electrophoretic analysis of a soluble fraction of Acetobacter aceti revealed the presence of several proteins whose production was enhanced, to various extents, in response to acetic acid in the medium. A protein with an apparent molecular mass of 100 kDa was significantly enhanced in amount by acetic acid and identified to be aconitase by NH2-terminal amino acid sequencing and subsequent gene cloning. Amplification of the aconitase gene by use of a multicopy plasmid in A. aceti enhanced the enzymatic activity and acetic acid resistance. These results showed that aconitase is concerned with acetic acid resistance. Enhancement of the aconitase activity turned out to be practically useful for acetic acid fermentation, because the A. aceti transformant harboring multiple copies of the aconitase gene produced a higher concentration of acetic acid with a reduced growth lag-time.

  9. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium acetate. 184.1721 Section 184.1721 Food and....1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3 or C2H3O2Na·3H2O, CAS Reg. No. 6131-90-4) is the sodium salt of acetic acid and occurs naturally in plant and animal tissues....

  10. The effect of pH and buffer concentration on anode biofilms of Thermincola ferriacetica.

    PubMed

    Lusk, Bradley G; Parameswaran, Prathap; Popat, Sudeep C; Rittmann, Bruce E; Torres, Cesar I

    2016-12-01

    We assessed the effects of pH and buffer concentration on current production and growth of biofilms of Thermincola ferriacetica - a thermophilic, Gram-positive, anode-respiring bacterium (ARB) - grown on anodes poised at a potential of -0.06V vs. SHE in microbial electrolysis cells (MECs) at 60°C. T. ferriacetica generated current in the pH range of 5.2 to 8.3 with acetate as the electron donor and 50mM bicarbonate buffer. Maximum current density was reduced by ~80% at pH5.2 and ~14% at 7.0 compared to pH8.3. Increasing bicarbonate buffer concentrations from 10mM to 100mM resulted in an increase in the current density by 40±6%, from 6.8±1.1 to 11.2±2.7Am(-2), supporting that more buffer alleviated pH depression within T. ferriacetica biofilms. Confocal laser scanning microscopy (CLSM) images indicated that higher bicarbonate buffer concentrations resulted in larger live biofilm thicknesses: from 68±20μm at 10mM bicarbonate to >150μm at 100mM, supporting that buffer availability was a strong influence on biofilm thickness. In comparison to mesophilic Geobacter sulfurreducens biofilms, the faster transport rates at higher temperature and the ability to grow at relatively lower pH allowed T. ferriacetica to produce higher current densities with lower buffer concentrations.

  11. The effect of pH and buffer concentration on anode biofilms of Thermincola ferriacetica.

    PubMed

    Lusk, Bradley G; Parameswaran, Prathap; Popat, Sudeep C; Rittmann, Bruce E; Torres, Cesar I

    2016-12-01

    We assessed the effects of pH and buffer concentration on current production and growth of biofilms of Thermincola ferriacetica - a thermophilic, Gram-positive, anode-respiring bacterium (ARB) - grown on anodes poised at a potential of -0.06V vs. SHE in microbial electrolysis cells (MECs) at 60°C. T. ferriacetica generated current in the pH range of 5.2 to 8.3 with acetate as the electron donor and 50mM bicarbonate buffer. Maximum current density was reduced by ~80% at pH5.2 and ~14% at 7.0 compared to pH8.3. Increasing bicarbonate buffer concentrations from 10mM to 100mM resulted in an increase in the current density by 40±6%, from 6.8±1.1 to 11.2±2.7Am(-2), supporting that more buffer alleviated pH depression within T. ferriacetica biofilms. Confocal laser scanning microscopy (CLSM) images indicated that higher bicarbonate buffer concentrations resulted in larger live biofilm thicknesses: from 68±20μm at 10mM bicarbonate to >150μm at 100mM, supporting that buffer availability was a strong influence on biofilm thickness. In comparison to mesophilic Geobacter sulfurreducens biofilms, the faster transport rates at higher temperature and the ability to grow at relatively lower pH allowed T. ferriacetica to produce higher current densities with lower buffer concentrations. PMID:27450427

  12. Origin and yields of acetic acid in pentose-based Maillard reaction systems.

    PubMed

    Davidek, Tomas; Gouézec, Elisabeth; Devaud, Stéphanie; Blank, Imre

    2008-04-01

    The formation of acetic acid from pentoses was studied in aqueous buffered systems (90-120 degrees C, pH 6.0-8.0) containing equimolar concentrations of 13C-labeled xylose and glycine. Acetic acid was quantified by gas chromatography-mass spectroscopy using an isotope dilution assay. Acetic acid was mainly formed from the C-1/C-2 carbon atoms of xylose (77-87%), while small amounts were also formed from the C-4/C-5 atoms of the pentose sugar (9-15%). Temperature and pH had only a small effect on the relative contribution of the sugar carbon atoms to acetic acid. These results support beta-dicarbonyl cleavage of 1-deoxypento-2,4-diulose as a major pathway leading to acetic acid in pentose-based Maillard reaction systems under food processing conditions. Acetic acid was confirmed as a major degradation product of pentoses at the early stage of the Maillard reaction, yielding 16 mol% and 28 mol% at pH 6.0 and pH 8.0, respectively. PMID:18448822

  13. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  14. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  15. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  16. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  17. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  18. 21 CFR 556.380 - Melengestrol acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Melengestrol acetate. 556.380 Section 556.380 Food... Tolerances for Residues of New Animal Drugs § 556.380 Melengestrol acetate. A tolerance of 25 parts per billion is established for residues of the parent compound, melengestrol acetate, in fat of cattle....

  19. 21 CFR 582.6185 - Calcium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Calcium acetate. 582.6185 Section 582.6185 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium acetate. (a) Product. Calcium acetate. (b) Conditions of use. This substance is...

  20. 21 CFR 582.6185 - Calcium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium acetate. 582.6185 Section 582.6185 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium acetate. (a) Product. Calcium acetate. (b) Conditions of use. This substance is...

  1. 21 CFR 582.6185 - Calcium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Calcium acetate. 582.6185 Section 582.6185 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium acetate. (a) Product. Calcium acetate. (b) Conditions of use. This substance is...

  2. 21 CFR 582.6185 - Calcium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Calcium acetate. 582.6185 Section 582.6185 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium acetate. (a) Product. Calcium acetate. (b) Conditions of use. This substance is...

  3. 21 CFR 582.6185 - Calcium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium acetate. 582.6185 Section 582.6185 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium acetate. (a) Product. Calcium acetate. (b) Conditions of use. This substance is...

  4. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  5. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  6. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  7. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  8. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  9. Photochemistry of 2-nitrobenzylidene acetals.

    PubMed

    Sebej, Peter; Solomek, Tomás; Hroudná, L'ubica; Brancová, Pavla; Klán, Petr

    2009-11-20

    Photolysis of dihydroxy compounds (diols) protected as 2-nitrobenzylidene acetals (ONBA) and subsequent acid- or base-catalyzed hydrolysis of the 2-nitrosobenzoic acid ester intermediates result in an efficient and high-yielding release of the substrates. We investigated the scope and limitations of ONBA photochemistry and expanded upon earlier described two-step procedures to show that the protected diols of many structural varieties can also be liberated in a one-pot procedure. In view of the fact that the acetals of nonsymmetrically substituted diols are converted into one of the corresponding 2-nitrosobenzoic acid ester isomers with moderate to high regioselectivity, the mechanism of their formation was studied using various experimental techniques. The experimental data were found to be in agreement with DFT-based quantum chemical calculations that showed the preferential cleavage occurs on the acetal C-O bond in the vicinity of more electron-withdrawing (or less electron-donating) groups. The study also revealed considerable complexity in the cleavage mechanism and that the structural variations in the substrate can significantly alter the reaction pathway. This deprotection strategy was found to be also applicable for 2-thioethanol when released from the corresponding monothioacetal in the presence of a reducing agent, such as ascorbic acid.

  10. Buffer-regulated biocorrosion of pure magnesium.

    PubMed

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

    2012-02-01

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

  11. 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.

  12. Eliminating Cell Broadband Engine™ DMA Buffer Overflows

    NASA Astrophysics Data System (ADS)

    Murase, Masana

    This paper presents effective and efficient implementation techniques for DMA buffer overflow elimination on the Cell Broadband Engine™ (Cell/B.E.) processor. In the Cell/B.E. programming model, application developers manually issue DMA commands to transfer data from the system memory to the local memories of the Cell/B.E. cores. Although this allows us to eliminate cache misses or cache invalidation overhead, it requires careful management of the buffer arrays for DMA in the application programs to prevent DMA buffer overflows. To guard against DMA buffer overflows, we introduced safe DMA handling functions for the applications to use. To improve and minimize the performance overhead of buffer overflow prevention, we used three different optimization techniques that take advantage of SIMD operations: branch-hint-based optimizations, jump-table-based optimizations and self-modifying-based optimizations. Our optimized implementation prevents all DMA buffer overflows with minimal performance overhead, only 2.93% average slowdown in comparison to code without the buffer overflow protection.

  13. 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.

  14. Optically pumped alkali laser and amplifier using helium-3 buffer gas

    DOEpatents

    Beach, Raymond J.; Page, Ralph; Soules, Thomas; Stappaerts, Eddy; Wu, Sheldon Shao Quan

    2010-09-28

    In one embodiment, a laser oscillator is provided comprising an optical cavity, the optical cavity including a gain medium including an alkali vapor and a buffer gas, the buffer gas including .sup.3He gas, wherein if .sup.4He gas is also present in the buffer gas, the ratio of the concentration of the .sup.3He gas to the .sup.4He gas is greater than 1.37.times.10.sup.-6. Additionally, an optical excitation source is provided. Furthermore, the laser oscillator is capable of outputting radiation at a first frequency. In another embodiment, an apparatus is provided comprising a gain medium including an alkali vapor and a buffer gas including .sup.3He gas, wherein if .sup.4He gas is also present in the buffer gas, the ratio of the concentration of the .sup.3He gas to the .sup.4He gas is greater than 1.37.times.10.sup.-6. Other embodiments are also disclosed.

  15. Heterotrophic and mixotrophic growth of Micractinium pusillum Fresenius in the presence of acetate and glucose: effect of light and acetate gradient concentration.

    PubMed

    Bouarab, L; Dauta, A; Loudiki, M

    2004-06-01

    The main objective of this study was to determine the importance of secondary mechanism of organic carbon utilization (mixotrophic and heterotrophic modes) in addition to CO2 fixation (photoautotrophic mode) in the green alga, Micractinium pusillum Fresenius (chlorophyta), isolated from a waste stabilization pond. The growth was studied in the presence of acetate and glucose. The incorporation rate of 14C- acetate was measured in the light and in the dark at different concentrations. Finally, in order to underline the role of photosynthesis and respiration processes in the acetate assimilation, the effect of two specific metabolic inhibitors, a specific inhibitor of photosystem II (DCMU) and an uncoupler respiratory (DNP), has been studied. The obtained results showed that M. pusillum grows in the presence of organic substrates, i.e., glucose and acetate, in the light (mixotrophic growth) as well as in the dark (Heterotrophic growth). The growth was much more important in the light than in the dark and more in the presence of glucose than of acetate. In the light, the presence of acetate led to a variation of growth parameters mumax, iotaopt, and beta. The effect of acetate gradient on the growth of the microalga was severe as soon as its concentration in the medium was higher. The acetate uptake followed a Michaelis-Menten kinetic in the light as well as in the dark. The capacity of assimilation was slightly higher in the dark. The utilization of DNP and DCMU indicates that acetate incorporation is an active process depending on both anabolic (photosynthesis) and catabolic (respiration) metabolisms, corroborating the model of the Michaelis-Menten kinetic.

  16. Acetate Dissimilation and Assimilation in Mycobacterium tuberculosis Depend on Carbon Availability

    PubMed Central

    Rücker, Nadine; Billig, Sandra; Bücker, René; Jahn, Dieter; Wittmann, Christoph

    2015-01-01

    ABSTRACT Mycobacterium tuberculosis persists inside granulomas in the human lung. Analysis of the metabolic composition of granulomas from guinea pigs revealed that one of the organic acids accumulating in the course of infection is acetate (B. S. Somashekar, A. G. Amin, C. D. Rithner, J. Troudt, R. Basaraba, A. Izzo, D. C. Crick, and D. Chatterjee, J Proteome Res 10:4186–4195, 2011, doi:http://dx.doi.org/10.1021/pr2003352), which might result either from metabolism of the pathogen or might be provided by the host itself. Our studies characterize a metabolic pathway by which M. tuberculosis generates acetate in the cause of fatty acid catabolism. The acetate formation depends on the enzymatic activities of Pta and AckA. Using actyl coenzyme A (acetyl-CoA) as a substrate, acetyl-phosphate is generated and finally dephosphorylated to acetate, which is secreted into the medium. Knockout mutants lacking either the pta or ackA gene showed significantly reduced acetate production when grown on fatty acids. This effect is even more pronounced when the glyoxylate shunt is blocked, resulting in higher acetate levels released to the medium. The secretion of acetate was followed by an assimilation of the metabolite when other carbon substrates became limiting. Our data indicate that during acetate assimilation, the Pta-AckA pathway acts in concert with another enzymatic reaction, namely, the acetyl-CoA synthetase (Acs) reaction. Thus, acetate metabolism might possess a dual function, mediating an overflow reaction to release excess carbon units and resumption of acetate as a carbon substrate. IMPORTANCE During infection, host-derived lipid components present the major carbon source at the infection site. β-Oxidation of fatty acids results in the formation of acetyl-CoA. In this study, we demonstrate that consumption of fatty acids by Mycobacterium tuberculosis activates an overflow mechanism, causing the pathogen to release excess carbon intermediates as acetate. The Pta

  17. Glucose metabolism and effect of acetate in ovine adipocytes.

    PubMed

    Yang, Y T; White, L S; Muir, L A

    1982-08-01

    Isolated ovine adipocytes were incubated in vitro with specifically labeled 14C-glucose in the presence or absence of acetate. The flux patterns of glucose carbon through major metabolic pathways were estimated. When glucose was added as the sole substrate, approximately equal portions of glucose carbon (10%) were oxidized to CO2 in the pentose phosphate pathway, in the pyruvate dehydrogenase reaction and in the citrate cycle. Fifteen percent of the glucose carbon was incorporated into fatty acids and 43% was released as lactate and pyruvate. Addition of acetate to the medium increased glucose carbon uptake by 1.5-fold. Most of this increase was accounted for by a sevenfold increase in the activity of the pentose phosphate pathway. Acetate increased glucose carbon fluxes via pentose phosphate pathway to triose phosphates, from triose phosphate to pyruvate, into glyceride glycerol, into lactate and pyruvate and into pyruvate dehydrogenase and citrate cycle CO2. Glucose carbon incorporated into fatty acids was decreased 50% by acetate while, carbon fluxes through the phosphofructokinase-aldolase reactions were not significantly increased. Results of this study suggest that, when glucose is the sole substrate, the conversion of glucose to fatty acids in ovine adipocytes may not be limited by the maximum capacity of hexokinase, the pentose phosphate pathway or enzymes involved in the conversion of triose phosphates to pyruvate and of pyruvate to fatty acid. Acetate increased glucose utilization apparently by increasing activity of the pentose phosphate pathway as a result of enhanced NADPH utilization for fatty acid synthesis. PMID:7142048

  18. Tolerance to acetic acid is improved by mutations of the TATA-binding protein gene.

    PubMed

    An, Jieun; Kwon, Hyeji; Kim, Eunjung; Lee, Young Mi; Ko, Hyeok Jin; Park, Hongjae; Choi, In-Geol; Kim, Sooah; Kim, Kyoung Heon; Kim, Wankee; Choi, Wonja

    2015-03-01

    Screening a library of overexpressing mutant alleles of the TATA-binding gene SPT15 yielded two Saccharomyces cerevisiae strains (MRRC 3252 and 3253) with enhanced tolerance to acetic acid. They were also tolerant to propionic acid and hydrogen peroxide. Transcriptome profile analysis identified 58 upregulated genes and 106 downregulated genes in MRRC 3252. Stress- and protein synthesis-related transcription factors were predominantly enriched in the upregulated and downregulated genes respectively. Eight deletion mutants for some of the highly downregulated genes were acetic acid-tolerant. The level of intracellular reactive oxygen species was considerably lessened in MRRC 3252 and 3253 upon exposure to acetic acid. Metabolome profile analysis revealed that intracellular concentrations of 5 and 102 metabolites were increased and decreased, respectively, in MRRC 3252, featuring a large increase of urea and a significant decrease of amino acids. The dur1/2Δmutant, in which the urea degradation gene DUR1/2 is deleted, displayed enhanced tolerance to acetic acid. Enhanced tolerance to acetic acid was also observed on the medium containing a low concentration of amino acids. Taken together, this study identified two SPT15 alleles, nine gene deletions and low concentration of amino acids in the medium that confer enhanced tolerance to acetic acid.

  19. 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.

  20. Buffer layer for thin film structures

    DOEpatents

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2010-06-15

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  1. Buffer layer for thin film structures

    DOEpatents

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2006-10-31

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  2. Buffer regulation of calcium puff sequences.

    PubMed

    Fraiman, Daniel; Dawson, Silvina Ponce

    2014-02-01

    Puffs are localized Ca(2 +) signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP3). They are the result of the liberation of Ca(2 +) from the endoplasmic reticulum through the coordinated opening of IP3 receptor/channels clustered at a functional release site. The presence of buffers that trap Ca(2 +) provides a mechanism that enriches the spatio-temporal dynamics of cytosolic calcium. The expression of different types of buffers along the cell's life provides a tool with which Ca(2 +) signals and their responses can be modulated. In this paper we extend the stochastic model of a cluster of IP3R-Ca(2 +) channels introduced previously to elucidate the effect of buffers on sequences of puffs at the same release site. We obtain analytically the probability laws of the interpuff time and of the number of channels that participate of the puffs. Furthermore, we show that under typical experimental conditions the effect of buffers can be accounted for in terms of a simple inhibiting function. Hence, by exploring different inhibiting functions we are able to study the effect of a variety of buffers on the puff size and interpuff time distributions. We find the somewhat counter-intuitive result that the addition of a fast Ca(2 +) buffer can increase the average number of channels that participate of a puff.

  3. Increase in peroxisome number and the gene expression of putative glyoxysomal enzymes in Chlamydomonas cells supplemented with acetate.

    PubMed

    Hayashi, Yasuko; Sato, Nagisa; Shinozaki, Akiko; Watanabe, Mariko

    2015-01-01

    We cultured Chlamydomonas reinhardtii cells in a minimal culture medium supplemented with various concentrations of acetate, fatty acids, ethanol, fatty alcohols, or sucrose. The presence of acetate (0.5 or 1.0%, w/v) was advantageous for cell growth. To determine whether peroxisomes are involved in fatty acid and fatty alcohol metabolism, we investigated the dynamics of peroxisomes, including changes in their number and size, in the presence of acetate, ethanol, and sucrose. The total volume of peroxisomes increased when cells were grown with acetate, but did not change when cells were grown with ethanol or sucrose. We analyzed cell growth on minimal culture medium supplemented with various fatty acids (carbon chain length ranging from one to ten) to investigate which fatty acids are metabolized by C. reinhardtii. Among them, acetate caused the greatest increase in growth when added to minimal culture media. We analyzed the transcript levels of genes encoding putative glyoxysomal enzymes. The transcript levels of genes encoding malate synthase, malate dehydrogenase, isocitrate lyase, and citrate synthase increased when Chlamydomonas cells were grown on minimal culture medium supplemented with acetate. Our results suggest that Chlamydomonas peroxisomes are involved in acetate metabolism via the glyoxylate cycle.

  4. Expression and specificity profile of the major acetate transporter AcpA in Aspergillus nidulans.

    PubMed

    Sá-Pessoa, Joana; Amillis, Sotiris; Casal, Margarida; Diallinas, George

    2015-03-01

    AcpA has been previously characterized as a high-affinity transporter essential for the uptake and use of acetate as sole carbon source in Aspergillus nidulans. Here, we follow the expression profile of AcpA and define its substrate specificity. AcpA-mediated acetate transport is detected from the onset of conidiospore germination, peaks at the time of germ tube emergence, and drops to low basal levels in germlings and young mycelia, where a second acetate transporter is also becoming apparent. AcpA activity also responds to acetate presence in the growth medium, but is not subject to either carbon or nitrogen catabolite repression. Short-chain monocarboxylates (benzoate, formate, butyrate and propionate) inhibit AcpA-mediated acetate transport with apparent inhibition constants (Ki) of 16.89±2.12, 9.25±1.01, 12.06±3.29 and 1.44±0.13mM, respectively. AcpA is also shown not to be directly involved in ammonia export, as proposed for its Saccharomyces cerevisiae homologue Ady2p. In the second part of this work, we search for the unknown acetate transporter expressed in mycelia, and for other transporters that might contribute to acetate uptake. In silico analysis, genetic construction of relevant null mutants, and uptake assays, reveal that the closest AcpA homologue (AN1839), named AcpB, is the 'missing' secondary acetate transporter in mycelia. We also identify two major short-chain carboxylate (lactate, succinate, pyruvate and malate) transporters, named JenA (AN6095) and JenB (AN6703), which however are not involved in acetate uptake. This work establishes a framework for further exploiting acetate and carboxylate transport in filamentous ascomycetes. PMID:25708319

  5. Photo-effects on the viscosity of titania nanoparticle suspensions in conducting and insulating medium

    NASA Astrophysics Data System (ADS)

    Smith, York R.; Heermance, David; Smith, Ryan N.

    2016-02-01

    The effect of illumination on the viscosity of titania suspensions in silicone oil (insulating medium) and an aqueous buffer (conducting medium) was investigated. Commercially available P25 anatase titania was suspended at a volume fraction of 0.5%. A 12.3% increase in viscosity was observed when silicone oil suspension was used as the medium, while a 2.47% decrease in viscosity was observed for the aqueous buffer suspension after exposure to UV-vis irradiation. The capability of the suspension medium to scavenge photoinduced charges results in the observed photorheological effects. The results presented here demonstrate a new method for influencing the rheological properties of nanoparticle suspensions.

  6. Helenalin Acetate in in vitro Propagated Plants of Arnica montana.

    PubMed

    Malarz, J; Stojakowska, A; Dohnal, B; Kisiel, W

    1993-02-01

    Propagated "IN VITRO" shoots and plantlets of ARNICA MONTANA L. (Asteraceae) have been shown to produce sesquiterpene lactones, i.e. helenalin and 11,13-dihydrohelenalin esters. The compounds were detected in green organs only; roots of the plantlets contained no sesquiterpene lactones. The helenalin acetate content in leaves of the plantlets (0.073% dry wt) was 4-times higher than in proliferated shoots (0.016% dry wt). The best rate of shoot multiplication was achieved on MS medium, supplemented with NAA 0.5mg/l and Kn 2.5 mg/l (formation of 22 shoots within 8 weeks).

  7. Biofiltration of ethyl acetate by Pseudomonas putida immobilized on walnut shell.

    PubMed

    Zare, Hossein; Najafpour, Ghasem; Rahimnejad, Mostafa; Tardast, Ali; Gilani, Saeedeh

    2012-11-01

    A biofilter packed with walnut shells was used to eliminate ethyl acetate from an air stream. The shells treated with NaOH were used as medium for immobilization of Pseudomonas putida PTCC 1694. At an empty bed residence time (EBRT) of 60s, a removal efficiency of 99% was achieved at inlet concentrations lower than 430ppm of ethyl acetate. The removal efficiency decreased below 80% with an increase in inlet concentration of ethyl acetate. When the EBRT was increased to 75 s, the removal efficiency remained above 80% even though the inlet loading rate was increased to 421g/m(3)h. Michaelis-Menten type and zero-order diffusion limited models were employed and the predicted data perfectly matched the experimental data. Thus P. putida immobilized on walnut shell has potential for the removal of ethyl acetate from air streams.

  8. Kinetic model for methanogenesis of acetic acid in a multireactor system

    SciTech Connect

    Bhadra, A.; Mukhopadhyay, S.N.; Ghose, T.K.

    1984-01-01

    Bioconversion of acetic acid to methane by a crude culture of methanogens in a continuous multireactor system was investigateed. Culture of methanogens was drawn from an active cow-dung digester (12 days) and was grown in a semisynthetic medium (pH 6.3, 37/sup 0/C) with acetic acid as the sole carbon source. The solubilities of CO/sub 2/, HCO/sub 3//sup -/ and CO/sub 3//sup 2 -/ increased with the rise in pH and exercised considerable influence on the gas composition. Various mechanisms for methanogenesis of acetic acid based on the available pathways were considered. Experimental data were compared with these mechansims, the best fit was determined, and the corresponding rate expression was identified. This mechanism predicted that, of the total methane produced, 72% comes from acetic acid directly and 28% via the CO/sub 2/ reduction route.

  9. Biofiltration of ethyl acetate by Pseudomonas putida immobilized on walnut shell.

    PubMed

    Zare, Hossein; Najafpour, Ghasem; Rahimnejad, Mostafa; Tardast, Ali; Gilani, Saeedeh

    2012-11-01

    A biofilter packed with walnut shells was used to eliminate ethyl acetate from an air stream. The shells treated with NaOH were used as medium for immobilization of Pseudomonas putida PTCC 1694. At an empty bed residence time (EBRT) of 60s, a removal efficiency of 99% was achieved at inlet concentrations lower than 430ppm of ethyl acetate. The removal efficiency decreased below 80% with an increase in inlet concentration of ethyl acetate. When the EBRT was increased to 75 s, the removal efficiency remained above 80% even though the inlet loading rate was increased to 421g/m(3)h. Michaelis-Menten type and zero-order diffusion limited models were employed and the predicted data perfectly matched the experimental data. Thus P. putida immobilized on walnut shell has potential for the removal of ethyl acetate from air streams. PMID:22940351

  10. Low noise buffer amplifiers and buffered phase comparators for precise time and frequency measurement and distribution

    NASA Technical Reports Server (NTRS)

    Eichinger, R. A.; Dachel, P.; Miller, W. H.; Ingold, J. S.

    1982-01-01

    Extremely low noise, high performance, wideband buffer amplifiers and buffered phase comparators were developed. These buffer amplifiers are designed to distribute reference frequencies from 30 KHz to 45 MHz from a hydrogen maser without degrading the hydrogen maser's performance. The buffered phase comparators are designed to intercompare the phase of state of the art hydrogen masers without adding any significant measurement system noise. These devices have a 27 femtosecond phase stability floor and are stable to better than one picosecond for long periods of time. Their temperature coefficient is less than one picosecond per degree C, and they have shown virtually no voltage coefficients.

  11. Influence of amino acids, buffers, and ph on the γ-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 γ-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.

  12. Medroxyprogesterone acetate exacerbates glutamate excitotoxicity.

    PubMed

    Nilsen, Jon; Morales, Alison; Brinton, Roberta Diaz

    2006-07-01

    We previously demonstrated that progesterone functions as a neuroprotective agent whereas medroxyprogesterone acetate (MPA; Provera) does not. Moreover, MPA antagonized the neuroprotective and neurotrophic outcomes induced by 17beta-estradiol (E2). Towards developing effective hormone therapies for protection against neurodegeneration, we sought to determine whether formulation, chemical features or prevention versus treatment mode of exposure affected the outcome of MPA treatment in survival of primary hippocampal neurons. Results of these analyses indicated that both crystalline MPA and a pharmaceutical formulation (Depo-Provera) lacked neuroprotective efficacy, indicating that the effects were not dependent upon MPA formulation. Likewise, MPA in the prevention and treatment paradigms were equally ineffective at promoting neuronal survival, indicating that timing of MPA administration was not a factor. Further, the detrimental effects of MPA were not due to the presence of the acetate group, as medroxyprogesterone was as ineffective as MPA in promoting neuronal survival. Moreover, MPA pretreatment exacerbated neuron death induced by glutamate excitotoxicity as indicated by a 40% increase in neuron death determined by direct live/dead cell count and a commensurate increase in the number of positive cells by terminal deoxynucleotidyl transferase-mediated nick end-labeling. Collectively these results predict that the progestin formulation of hormone therapy will affect the vulnerability of the central nervous system to degenerative insults.

  13. Dexamethasone and Acetate Modulate Cytoplasmic Leptin in Bovine Preadipocytes

    PubMed Central

    Yonekura, Shinichi; Hirota, Shohei; Tokutake, Yukako; Rose, Michael T.; Katoh, Kazuo; Aso, Hisashi

    2014-01-01

    Hormonal and nutrient signals regulate leptin synthesis and secretion. In rodents, leptin is stored in cytosolic pools of adipocytes. However, not much information is available regarding the regulation of intracellular leptin in ruminants. Recently, we demonstrated that leptin mRNA was expressed in bovine intramuscular preadipocyte cells (BIP cells) and that a cytoplasmic leptin pool may be present in preadipocytes. In the present study, we investigated the expression of cytoplasmic leptin protein in BIP cells during differentiation as well as the effects of various factors added to the differentiation medium on its expression in BIP cells. Leptin mRNA expression was observed only at 6 and 8 days after adipogenic induction, whereas the cytoplasmic leptin concentration was the highest on day 0 and decreased gradually thereafter. Cytoplasmic leptin was detected at 6 and 8 days after adipogenic induction, but not at 4 days after adipogenic induction. The cytoplasmic leptin concentration was reduced in BIP cells at 4 days after treatment with dexamethasone, whereas cytoplasmic leptin was not observed at 8 days after treatment. In contrast, acetate significantly enhanced the cytoplasmic leptin concentration in BIP cells at 8 days after treatment, although acetate alone did not induce adipocyte differentiation in BIP cells. These results suggest that dexamethasone and acetate modulate the cytoplasmic leptin concentration in bovine preadipocytes. PMID:25049989

  14. Understanding Palladium Acetate from a User Perspective.

    PubMed

    Carole, William A; Colacot, Thomas J

    2016-06-01

    The behavior of palladium acetate is reviewed with respect to its synthesis, characterization, structure (in both solution and solid state), and activation pathways. In addition, comparisons of catalytic activities between pure palladium acetate and two common byproducts, Pd3 (OAc)5 (NO2 ) and polymeric [Pd(OAc)2 ]n , typically present in commercially available material are reviewed. Hence, this minireview serves as a concise guide for the users of palladium acetate from both academia and industry. PMID:27125630

  15. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... sodium sulfate and sodium bicarbonate. (b) The ingredient meets the specifications of the Food Chemicals... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium acetate. 184.1721 Section 184.1721 Food and... Substances Affirmed as GRAS § 184.1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3...

  16. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... sodium sulfate and sodium bicarbonate. (b) The ingredient meets the specifications of the Food Chemicals... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium acetate. 184.1721 Section 184.1721 Food and... Substances Affirmed as GRAS § 184.1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3...

  17. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... sodium sulfate and sodium bicarbonate. (b) The ingredient meets the specifications of the Food Chemicals... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium acetate. 184.1721 Section 184.1721 Food and... Substances Affirmed as GRAS § 184.1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3...

  18. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... sodium sulfate and sodium bicarbonate. (b) The ingredient meets the specifications of the Food Chemicals... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium acetate. 184.1721 Section 184.1721 Food and... Substances Affirmed as GRAS § 184.1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3...

  19. 12 CFR 324.11 - Capital conservation buffer and countercyclical capital buffer amount.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... Additional limitations on distributions may apply to an FDIC-supervised institution under 12 CFR 303.241 and... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Capital conservation buffer and countercyclical capital buffer amount. 324.11 Section 324.11 Banks and Banking FEDERAL DEPOSIT INSURANCE...

  20. Undergraduate Chemistry Students' Perceptions of and Misconceptions about Buffers and Buffer Problems

    ERIC Educational Resources Information Center

    Orgill, MaryKay; Sutherland, Aynsley

    2008-01-01

    Both upper- and lower-level chemistry students struggle with understanding the concept of buffers and with solving corresponding buffer problems. While it might be reasonable to expect general chemistry students to struggle with this abstract concept, it is surprising that upper-level students in analytical chemistry and biochemistry continue to…

  1. 12 CFR 3.11 - Capital conservation buffer and countercyclical capital buffer amount.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... or Federal savings association under subparts H and I of this part; 12 CFR 5.46, 12 CFR part 5, subpart E; 12 CFR part 6. (b) Countercyclical capital buffer amount. (1) General. An advanced approaches... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Capital conservation buffer and...

  2. 12 CFR 217.11 - Capital conservation buffer and countercyclical capital buffer amount.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... distributions. Additional limitations on distributions may apply to a Board-regulated institution under 12 CFR 225.4, 12 CFR 225.8, and 12 CFR 263.202. (b) Countercyclical capital buffer amount. (1) General. An... 12 Banks and Banking 2 2014-01-01 2014-01-01 false Capital conservation buffer and...

  3. 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.

  4. Nonlinear spelling in graphemic buffer deficit.

    PubMed

    Schubert, Teresa; Nickels, Lyndsey

    2015-01-01

    In this paper, we describe a case of nonlinear spelling and its implications for theories of the graphemic buffer. C.T.J., an individual with an acquired deficit of the graphemic buffer, often wrote the letters of his responses in a nonlinear temporal order when writing to dictation. The spatial ordering of the letters was maintained: Letters in the later positions of the words were written towards the right side of the response, even when written before letters in earlier positions. This unusual phenomenon has been briefly reported in three prior cases but this study provides the most detailed analysis of the phenomenon to date. We specifically contend that the decoupling of the temporal and spatial aspects of spelling is difficult to reconcile with competitive queuing accounts of the graphemic buffer. PMID:27355609

  5. Meta-analysis of nitrogen removal in riparian buffers.

    PubMed

    Mayer, Paul M; Reynolds, Steven K; McCutchen, Marshall D; Canfield, Timothy J

    2007-01-01

    Riparian buffers, the vegetated region adjacent to streams and wetlands, 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 groundwater to identify trends between nitrogen removal effectiveness and buffer width, hydrological flow path, and vegetative cover. Nitrogen removal effectiveness varied widely. Wide buffers (>50 m) more consistently removed significant portions of nitrogen entering a riparian zone than narrow buffers (0-25 m). Buffers of various vegetation types were equally effective at removing nitrogen but buffers composed of herbaceous and forest/herbaceous vegetation were more effective when wider. Subsurface removal of nitrogen was efficient, but did not appear to be related to buffer width, while surface removal of nitrogen was partly related to buffer width. The mass of nitrate nitrogen removed per unit length of buffer did not differ by buffer width, flow path, or buffer vegetation type. Our meta-analysis suggests that buffer width is an important consideration in managing nitrogen in watersheds. However, the inconsistent effects of buffer width and vegetation on nitrogen removal suggest that soil type, subsurface hydrology (e.g., soil saturation, groundwater flow paths), and subsurface biogeochemistry (organic carbon supply, nitrate inputs) also are important factors governing nitrogen removal in buffers.

  6. Acetate Assimilation by Nitrobacter agilis in Relation to Its “Obligate Autotrophy”

    PubMed Central

    Smith, Arnold J.; Hoare, Derek S.

    1968-01-01

    Acetate (1 to 10 mm) had no effect on the rate of nitrite oxidation or exponential growth by Nitrobacter agilis. However, acetate-1-14C and -2-14C were both assimilated by growing cultures, and acetate carbon contributed 33 to 39% of newly synthesized cell carbon. Carbon from acetate was incorporated into all of the major cell constituents, including most of the amino acids of cell protein and poly-β-hydroxybutyrate (PHB). Cultures grown in the presence of acetate showed a significant increase in turbidity, attributable in part to protein synthesis and the accumulation of PHB in the “post-exponential phase,” when the supply of nitrite was completely exhausted. Cell suspensons of N. agilis assimilated acetate in the absence of bicarbonate and even in the absence of nitrite. However, the addition of nitrite increased the rate of acetate assimilation by cell suspensions. The distribution of 14C-acetate incorporated by cell suspensions was qualitatively similar to that found with growing cultures. Cell suspensions of N. agilis slowly oxidized acetate to CO2. Addition of nitrite suppressed CO2 production from acetate but increased the assimilation of acetate carbon into cell material. N. agilis contained all the enzymes of the tricarboxylic acid cycle. Growth of N. agilis in the presence of acetate did not significantly affect the levels of the enzymes of the tricarboxylic acid cycle, but did result in a 100-fold increase in the specific activity of isocitratase. In contrast, carboxydismutase was partially repressed. N. agilis was grown heterotrophically through seven transfers on a medium containing acetate and casein hydrolysate. The addition of nitrite increased the rate of heterotrophic growth. Heterotrophically grown organisms still retained their ability to grow autotrophically with nitrite. However, these organisms oxidized nitrite at a slower rate. Organisms from autotrophic and heterotrophic cultures were analyzed to determine the mean guanine plus

  7. Riparian forests buffer panel final report

    SciTech Connect

    1996-10-01

    The Chesapeake Executive Council adopted Directive 94-1 which called upon the Chesapeake Bay Program to develop a set of goals and actions to increase the focus on riparian stewardship and enhance efforts to conserve and restore riparian forest buffers. The Council appointed a panel to recommend a set of policies, recommend an accepted definition of forest buffers, and suggest quantifiable goals. The Panel was a diverse group of thirty-one members, comprised of federal, state, and local government representatives, scientists, land managers, citizens, and farming, development, forest industry, and environmental interests. This report contains our principal findings and recommendations.

  8. Preparation of Buffers. An Experiment for Quantitative Analysis Laboratory

    NASA Astrophysics Data System (ADS)

    Buckley, P. T.

    2001-10-01

    In our experience, students who have a solid grounding in the theoretical aspects of buffers, buffer preparation, and buffering capacity are often at a loss when required to actually prepare a buffer in a research setting. However, there are very few published laboratory experiments pertaining to buffers. This laboratory experiment for the undergraduate quantitative analysis lab gives students hands-on experience in the preparation of buffers. By preparing a buffer to a randomly chosen pH value and comparing the theoretical pH to the actual pH, students apply their theoretical understanding of the Henderson-Hasselbalch equation, activity coefficients, and the effect of adding acid or base to a buffer. This experiment gives students experience in buffer preparation for research situations and helps them in advanced courses such as biochemistry where a fundamental knowledge of buffer systems is essential.

  9. Anaerobic degradation of lactate by syntrophic associations of methanosarcina barkeri and desulfovibrio species and effect of H2 on acetate degradation

    SciTech Connect

    McInerney, M.J.; Bryant, M.P.

    1981-02-01

    When grown in the absence of added sulfate, cocultures of Desulfovibrio desulfuricans or Desulfovibrio vulgaris with Methanobrevibacter smithii (Methanobacterium ruminantium), which uses H2 and CO2 for methanogenesis, degraded lactate, with the production of acetate and CH4. When D. desulfuricans or D. vulgaris was grown in the absence of added sulfate in coculture with Methanosarcina barkeri (type strain), which uses both H2-CO2 and acetate for methanogenesis, lactate was stoichiometrically degraded to CH4 and presumably to CO2. During the first 12 days of incubation of the D. desulfuricans-M. barkeri coculture, lactate was completely degraded, with almost stoichiometric production of acetate and CH4. Later, acetate was degraded to CH4 and presumably to CO2. In experiments in which 20 mM acetate and 0 to 20 mM lactate were added to D. desulfuricans-M. barkeri cocultures, no detectable degradation of acetate occurred until the lactate was catabolized. The ultimate rate of acetate utilization for methanogenesis was greater for those cocultures receiving the highest levels of lactate. A small amount of H2 was detected in cocultures which contained D. desulfuricans and M. barkeri until after all lactate was degraded. The addition of H2, but not of lactate, to the growth medium inhibited acetate degradation by pure cultures of M. barkeri. Pure cultures of M. barkeri produced CH4 from acetate at a rate equivalent to that observed for cocultures containing M. barkeri. Inocula of M. barkeri grown with H2-CO2 as the methanogenic substrate produced CH4 from acetate at a rate equivalent to that observed for acetate-grown inocula when grown in a rumen fluid-vitamin-based medium but not when grown in a yeast extract-based medium. The results suggest that H2 produced by the Desulfovibrio species during growth with lactate inhibited acetate degradation by M. barkeri. (Refs. 26).

  10. 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 ...

  11. Validation of a multi-analyte HPLC-DAD method for determination of uric acid, creatinine, homovanillic acid, niacinamide, hippuric acid, indole-3-acetic acid and 2-methylhippuric acid in human urine.

    PubMed

    Remane, Daniela; Grunwald, Soeren; Hoeke, Henrike; Mueller, Andrea; Roeder, Stefan; von Bergen, Martin; Wissenbach, Dirk K

    2015-08-15

    During the last decades exposure sciences and epidemiological studies attracts more attention to unravel the mechanisms for the development of chronic diseases. According to this an existing HPLC-DAD method for determination of creatinine in urine samples was expended for seven analytes and validated. Creatinine, uric acid, homovanillic acid, niacinamide, hippuric acid, indole-3-acetic acid, and 2-methylhippuric acid were separated by gradient elution (formate buffer/methanol) using an Eclipse Plus C18 Rapid Resolution column (4.6mm×100mm). No interfering signals were detected in mobile phase. After injection of blank urine samples signals for the endogenous compounds but no interferences were detected. All analytes were linear in the selected calibration range and a non weighted calibration model was chosen. Bias, intra-day and inter-day precision for all analytes were below 20% for quality control (QC) low and below 10% for QC medium and high. The limits of quantification in mobile phase were in line with reported reference values but had to be adjusted in urine for homovanillic acid (45mg/L), niacinamide 58.5(mg/L), and indole-3-acetic acid (63mg/L). Comparison of creatinine data obtained by the existing method with those of the developed method showing differences from -120mg/L to +110mg/L with a mean of differences of 29.0mg/L for 50 authentic urine samples. Analyzing 50 authentic urine samples, uric acid, creatinine, hippuric acid, and 2-methylhippuric acid were detected in (nearly) all samples. However, homovanillic acid was detected in 40%, niacinamide in 4% and indole-3-acetic acid was never detected within the selected samples.

  12. Variation in Resistance of Mycobacterium paratuberculosis to Acid Environments as a Function of Culture Medium

    PubMed Central

    Sung, Nackmoon; Collins, Michael T.

    2003-01-01

    Acid resistance of Mycobacterium paratuberculosis was examined as a function of growth conditions (i.e., in vitro growth medium and pH). M. paratuberculosis was cultured in either fatty acid-containing medium (7H9-OADC) or glycerol-containing medium (WR-GD or 7H9-GD) at two culture pHs (pHs 6.0 and 6.8). Organisms produced in these six medium and pH conditions were then tested for resistance to acetate buffer at pHs 3, 4, 5, and 6 at 20°C. A radiometric culture method (BACTEC) was used to quantify viable M. paratuberculosis cell data at various acid exposure times, and D values (decimal reduction times, or the times required to kill a 1-log10 concentration of bacteria) were determined. Soluble proteins of M. paratuberculosis grown under all six conditions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to identify proteins that may be associated with acid resistance or susceptibility. The culture medium affected growth rate and morphology: thin floating sheets of cells were observed in 7H9-OADC versus confluent, thick, waxy, and wrinkled pellicles in WR-GD. Culture medium pH affected growth rate (which was highest at pH 6.0), but it had little or no effect on D values for M. paratuberculosis at any test pH. When grown in 7H9-OADC, M. paratuberculosis was more acid resistant at all test pHs (higher D values) than when grown in WR-GD. Glycerol appeared to be the culture medium component most responsible for lower levels of M. paratuberculosis acid resistance. When glycerol was substituted for OADC in the 7H9 medium, D values were significantly lower than those of 7H9-OADC-grown M. paratuberculosis and were approximately the same as those for M. paratuberculosis grown in WR-GD medium. Comparison of the SDS-PAGE protein profiles for M. paratuberculosis cultures grown in 7H9-OADC, WR-GD, or 7H9-GD medium revealed that increased expression of 34.2- and 14.0-kDa proteins was associated with higher levels of acid resistance of M

  13. MrpA functions in energy conversion during acetate-dependent growth of Methanosarcina acetivorans.

    PubMed

    Jasso-Chávez, Ricardo; Apolinario, Ethel E; Sowers, Kevin R; Ferry, James G

    2013-09-01

    The role of the multisubunit sodium/proton antiporter (Mrp) of Methanosarcina acetivorans was investigated with a mutant deleted for the gene encoding the MrpA subunit. Antiporter activity was 5-fold greater in acetate-grown versus methanol-grown wild-type cells, consistent with the previously published relative levels of mrp transcript. The rate, final optical density, and dry weight/methane ratio decreased for the mutant versus wild type when cultured with a growth-limiting concentration of acetate. All growth parameters of the mutant or wild type were identical when grown with methanol in medium containing a growth-limiting Na(+) concentration of 1.04 M. The lag phase, growth rate, and final optical density for growth of the mutant were suboptimal compared to the wild type when cultured with acetate in medium containing either 0.54 or 1.04 M Na(+). The addition of 25 mM NaCl to resting cell suspensions stimulated ATP synthesis driven by a potassium diffusion potential. ATP synthesis was greater in wild-type than mutant cells grown with acetate, a trend that held for methanol-grown cells, albeit less pronounced. Both sodium and proton ionophores reduced ATP synthesis in the wild type grown with either substrate. The results indicated that the Mrp complex is essential for efficient ATP synthesis and optimal growth at the low concentrations of acetate encountered in the environment.

  14. In vivo predictive dissolution: transport analysis of the CO2 , bicarbonate in vivo buffer system.

    PubMed

    Krieg, Brian J; Taghavi, Seyed Mohammad; Amidon, Gordon L; Amidon, Gregory E

    2014-11-01

    Development of an oral in vivo predictive dissolution medium for acid drugs with a pKa in the physiological range (e.g., Biopharmaceutics Classification System Class IIa) requires transport analysis of the complex in vivo CO2 /bicarbonate buffering system. In this report, we analyze this buffer system using hydrodynamically defined rotating disk dissolution. Transport analysis of drug flux was predicted using the film model approach of Mooney et al based on equilibrium assumptions as well as accounting for the slow hydration reaction, CO2 + H2 O → H2 CO3 . The accuracy of the models was compared with experimentally determined results using the rotating disk dissolution of ibuprofen, indomethacin, and ketoprofen. The equilibrium and slow hydration reaction rate models predict significantly different dissolution rates. The experimental results are more accurately predicted by accounting for the slow hydration reaction under a variety of pH and hydrodynamic conditions. Although the complex bicarbonate buffering system requires further consideration given its dynamic nature in vivo, a simplifying irreversible reaction (IRR) transport analysis accurately predicts in vitro rotating disk dissolution rates of several carboxylic acid drugs. This IRR transport model provides further insight into bicarbonate buffer and can be useful in developing more physiologically relevant buffer systems for dissolution testing.

  15. Peak distortion in the column liquid chromatographic determination of omeprazole dissolved in borax buffer.

    PubMed

    Arvidsson, T; Collijn, E; Tivert, A M; Rosén, L

    1991-11-22

    Injection of a sample containing omeprazole dissolved in borax buffer (pH 9.2) into a reversed-phase liquid chromatographic system consisting of a mixture of acetonitrile and phosphate buffer (pH 7.6) as the mobile phase and a C18 surface-modified silica as the solid phase resulted under special conditions in split peaks of omeprazole. The degree of peak split and the retention time of omeprazole varied with the concentration of borax in the sample solution and the ionic strength of the mobile phase buffer as well as with the column used. Borax is eluted from the column in a broad zone starting from the void volume of the column. The retention is probably due to the presence of polyborate ions. The size of the zone varies with the concentration of borax in the sample injected. In the borax zone the pH is increased compared with the pH of the mobile phase, and when omeprazole (a weak acid) is co-eluting in the borax zone its retention is affected. In the front part and in the back part of the borax zone, pH gradients are formed, and these gradients can induce the peak splitting. When the dissolving medium is changed to a phosphate buffer or an ammonium buffer at pH 9 no peak distortion of omeprazole is observed.

  16. Buffers more than buffering agent: introducing a new class of stabilizers for the protein BSA.

    PubMed

    Gupta, Bhupender S; Taha, Mohamed; Lee, Ming-Jer

    2015-01-14

    In this study, we have analyzed the influence of four biological buffers on the thermal stability of bovine serum albumin (BSA) using dynamic light scattering (DLS). The investigated buffers include 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES), 4-(2-hydroxyethyl)-1-piperazine-propanesulfonic acid (EPPS), 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid sodium salt (HEPES-Na), and 4-morpholinepropanesulfonic acid sodium salt (MOPS-Na). These buffers behave as a potential stabilizer for the native structure of BSA against thermal denaturation. The stabilization tendency follows the order of MOPS-Na > HEPES-Na > HEPES ≫ EPPS. To obtain an insight into the role of hydration layers and peptide backbone in the stabilization of BSA by these buffers, we have also explored the phase transition of a thermoresponsive polymer, poly(N-isopropylacrylamide (PNIPAM)), a model compound for protein, in aqueous solutions of HEPES, EPPS, HEPES-Na, and MOPS-Na buffers at different concentrations. It was found that the lower critical solution temperatures (LCST) of PNIPAM in the aqueous buffer solutions substantially decrease with increase in buffer concentration. The mechanism of interactions between these buffers and protein BSA was probed by various techniques, including UV-visible, fluorescence, and FTIR. The results of this series of studies reveal that the interactions are mainly governed by the influence of the buffers on the hydration layers surrounding the protein. We have also explored the possible binding sites of BSA with these buffers using a molecular docking technique. Moreover, the activities of an industrially important enzyme α-chymotrypsin (α-CT) in 0.05 M, 0.5 M, and 1.0 M of HEPES, EPPS, HEPES-Na, and MOPS-Na buffer solutions were analyzed at pH = 8.0 and T = 25 °C. Interestingly, the activities of α-CT were found to be enhanced in the aqueous solutions of these investigated buffers. Based upon the Jones-Dole viscosity parameters, the

  17. Tri-color emission and colorimetric recognition of acetate using semicarbazide and thio-semicarbazide derivatives: Experimental and computational studies

    NASA Astrophysics Data System (ADS)

    Lohar, Sisir; Sinha, Sougata; Ghosh, Subrata; Das, Debasis

    2016-02-01

    Two new fluorescence probes having semicarbazide (DSC) and thio-semicarbazide (DTSC) units have been derived upon reaction with 2-hydroxy-5-methylbenzene-1,3-dialdehyde. Both the probes show excellent selectivity for acetate ion in DMSO medium whereby DTSC generates tricolor emission. The association constants of DSC and DTSC for acetate are 6.6×104 M- 1 and 2 × 103 M- 1 respectively with corresponding detection limits, 1.06×10- 7M and 2.5×10- 6 M. Density functional theoretical (DFT) studies nicely demonstrate the interaction between the DTSC and acetate ion.

  18. 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.

  19. Change in the plasmid copy number in acetic acid bacteria in response to growth phase and acetic acid concentration.

    PubMed

    Akasaka, Naoki; Astuti, Wiwik; Ishii, Yuri; Hidese, Ryota; Sakoda, Hisao; Fujiwara, Shinsuke

    2015-06-01

    Plasmids pGE1 (2.5 kb), pGE2 (7.2 kb), and pGE3 (5.5 kb) were isolated from Gluconacetobacter europaeus KGMA0119, and sequence analyses revealed they harbored 3, 8, and 4 genes, respectively. Plasmid copy numbers (PCNs) were determined by real-time quantitative PCR at different stages of bacterial growth. When KGMA0119 was cultured in medium containing 0.4% ethanol and 0.5% acetic acid, PCN of pGE1 increased from 7 copies/genome in the logarithmic phase to a maximum of 12 copies/genome at the beginning of the stationary phase, before decreasing to 4 copies/genome in the late stationary phase. PCNs for pGE2 and pGE3 were maintained at 1-3 copies/genome during all phases of growth. Under a higher concentration of ethanol (3.2%) the PCN for pGE1 was slightly lower in all the growth stages, and those of pGE2 and pGE3 were unchanged. In the presence of 1.0% acetic acid, PCNs were higher for pGE1 (10 copies/genome) and pGE3 (6 copies/genome) during the logarithmic phase. Numbers for pGE2 did not change, indicating that pGE1 and pGE3 increase their PCNs in response to acetic acid. Plasmids pBE2 and pBE3 were constructed by ligating linearized pGE2 and pGE3 into pBR322. Both plasmids were replicable in Escherichia coli, Acetobacter pasteurianus and G. europaeus, highlighting their suitability as vectors for acetic acid bacteria.

  20. Change in the plasmid copy number in acetic acid bacteria in response to growth phase and acetic acid concentration.

    PubMed

    Akasaka, Naoki; Astuti, Wiwik; Ishii, Yuri; Hidese, Ryota; Sakoda, Hisao; Fujiwara, Shinsuke

    2015-06-01

    Plasmids pGE1 (2.5 kb), pGE2 (7.2 kb), and pGE3 (5.5 kb) were isolated from Gluconacetobacter europaeus KGMA0119, and sequence analyses revealed they harbored 3, 8, and 4 genes, respectively. Plasmid copy numbers (PCNs) were determined by real-time quantitative PCR at different stages of bacterial growth. When KGMA0119 was cultured in medium containing 0.4% ethanol and 0.5% acetic acid, PCN of pGE1 increased from 7 copies/genome in the logarithmic phase to a maximum of 12 copies/genome at the beginning of the stationary phase, before decreasing to 4 copies/genome in the late stationary phase. PCNs for pGE2 and pGE3 were maintained at 1-3 copies/genome during all phases of growth. Under a higher concentration of ethanol (3.2%) the PCN for pGE1 was slightly lower in all the growth stages, and those of pGE2 and pGE3 were unchanged. In the presence of 1.0% acetic acid, PCNs were higher for pGE1 (10 copies/genome) and pGE3 (6 copies/genome) during the logarithmic phase. Numbers for pGE2 did not change, indicating that pGE1 and pGE3 increase their PCNs in response to acetic acid. Plasmids pBE2 and pBE3 were constructed by ligating linearized pGE2 and pGE3 into pBR322. Both plasmids were replicable in Escherichia coli, Acetobacter pasteurianus and G. europaeus, highlighting their suitability as vectors for acetic acid bacteria. PMID:25575969

  1. O-buffer: a framework for sample-based graphics.

    PubMed

    Qu, Huamin; Kaufman, Arie E

    2004-01-01

    We present an innovative modeling and rendering primitive, called the O-buffer, as a framework for sample-based graphics. The 2D or 3D O-buffer is, in essence, a conventional image or a volume, respectively, except that samples are not restricted to a regular grid. A sample position in the O-buffer is recorded as an offset to the nearest grid point of a regular base grid (hence the name O-buffer). The O-buffer can greatly improve the expressive power of images and volumes. Image quality can be improved by storing more spatial information with samples and by avoiding multiple resamplings. It can be exploited to represent and render unstructured primitives, such as points, particles, and curvilinear or irregular volumes. The O-buffer is therefore a unified representation for a variety of graphics primitives and supports mixing them in the same scene. It is a semiregular structure which lends itself to efficient construction and rendering. O-buffers may assume a variety of forms including 2D O-buffers, 3D O-buffers, uniform O-buffers, nonuniform O-buffers, adaptive O-buffers, layered-depth O-buffers, and O-buffer trees. We demonstrate the effectiveness of the O--buffer in a variety of applications, such as image-based rendering, point sample rendering, and volume rendering. PMID:18579969

  2. Analysis of mutational lesions of acetate metabolism in Neurospora crassa by 13C nuclear magnetic resonance.

    PubMed Central

    Thomas, G H; Baxter, R L

    1987-01-01

    The adaptation of Neurospora crassa mycelium to growth on acetate as the sole carbon source was examined by using 13C nuclear magnetic resonance. Extracts were examined by nuclear magnetic resonance at various times after transfer of the mycelium from medium containing sucrose to medium containing [2-13C]acetate as the sole carbon source. The label was initially seen to enter the alanine, glutamate, and glutamine pools, and after 6 h 13C-enriched trehalose was evident, indicating that gluconeogenesis was occurring. Analysis of the isotopomer ratios in the alanine and glutamate-glutamine pools indicated that substantial glyoxylate cycle activity became evident between 2 and 4 h after transfer. Immediately after transfer of the mycelium to acetate medium, the alanine pool increased to about four times its previous level, only a small fraction of which was enriched with 13C. The quantity of 13C-enriched alanine remained almost constant between 2 and 7.5 h after the transfer, whereas the overall alanine pool decreased to its original level. The selective catabolism of the unenriched alanine leads us to suggest that the alanine pool is partitioned into two compartments during adaptation. Two acetate-nonutilizing mutants were also studied by this technique. An acu-3 strain, deficient for isocitrate lyase (EC 4.1.3.1) activity, showed metabolic changes consistent with this lesion. An acp strain, previously thought to be deficient in an inducible acetate permease, took up [2-13C]acetate but showed no evidence of glyoxylate cycle activity despite synthesizing the necessary enzymes; the lesion was therefore reinterpreted. PMID:2947898

  3. 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

  4. Body Buffer Zone and Proxemics in Blocking.

    ERIC Educational Resources Information Center

    Stockwell, John C.; Bahs, Clarence W.

    This paper investigates the effect of personal body buffer zones on compositional arrangements staged by novice directors. Relationships between directors' concepts of personal space and their projection of its dimensions into staging are studied through the use of a variety of proximity measures--distance, area angles of approach, and physical…

  5. 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…

  6. Negative feedback buffers effects of regulatory variants

    PubMed Central

    Bader, Daniel M; Wilkening, Stefan; Lin, Gen; Tekkedil, Manu M; Dietrich, Kim; Steinmetz, Lars M; Gagneur, Julien

    2015-01-01

    Mechanisms conferring robustness against regulatory variants have been controversial. Previous studies suggested widespread buffering of RNA misexpression on protein levels during translation. We do not find evidence that translational buffering is common. Instead, we find extensive buffering at the level of RNA expression, exerted through negative feedback regulation acting in trans, which reduces the effect of regulatory variants on gene expression. Our approach is based on a novel experimental design in which allelic differential expression in a yeast hybrid strain is compared to allelic differential expression in a pool of its spores. Allelic differential expression in the hybrid is due to cis-regulatory differences only. Instead, in the pool of spores allelic differential expression is not only due to cis-regulatory differences but also due to local trans effects that include negative feedback. We found that buffering through such local trans regulation is widespread, typically compensating for about 15% of cis-regulatory effects on individual genes. Negative feedback is stronger not only for essential genes, indicating its functional relevance, but also for genes with low to middle levels of expression, for which tight regulation matters most. We suggest that negative feedback is one mechanism of Waddington's canalization, facilitating the accumulation of genetic variants that might give selective advantage in different environments. PMID:25634765

  7. The buffer effect in neutral electrolyte supercapacitors

    NASA Astrophysics Data System (ADS)

    Vindt, Steffen T.; Skou, Eivind M.

    2016-02-01

    The observation that double-layer capacitors based on neutral aqueous electrolytes can have significantly wider usable potential windows than those based on acidic or alkaline electrolytes is studied. This effect is explained by a local pH change taking place at the electrode surfaces, leading to a change in the redox potential of water in opposite directions on the two electrodes, resulting in the wider stability window. The magnitude of this effect is suggested to be dependent on the buffer capacity, rather than the intrinsic pH value of the electrolyte. This is confirmed by studying the impact of addition of a buffer to such systems. It is shown that a 56 % higher dynamic storage capacity may be achieved, simply by controlling the buffer capacity of the electrolyte. The model system used, is based on a well-known commercial activated carbon (NORIT™ A SUPRA) as the electrode material, aqueous potassium nitrate as the electrolyte and potassium phosphates as the buffer system.

  8. Buffer layers on biaxially textured metal substrates

    DOEpatents

    Shoup, Shara S.; Paranthamam, Mariappan; Beach, David B.; Kroeger, Donald M.; Goyal, Amit

    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.

  9. 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.

  10. 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

  11. Basal buffer systems for a newly glycosylated recombinant human interferon-β with biophysical stability and DoE approaches.

    PubMed

    Kim, Nam Ah; Song, Kyoung; Lim, Dae Gon; Hada, Shavron; Shin, Young Kee; Shin, Sangmun; Jeong, Seong Hoon

    2015-10-12

    The purpose of this study was to develop a basal buffer system for a biobetter version of recombinant human interferon-β 1a (rhIFN-β 1a), termed R27T, to optimize its biophysical stability. The protein was pre-screened in solution as a function of pH (2-11) using differential scanning calorimetry (DSC) and dynamic light scattering (DLS). According to the result, its experimental pI and optimal pH range were 5.8 and 3.6-4.4, respectively. Design of experiment (DoE) approach was developed as a practical tool to aid formulation studies as a function of pH (2.9-5.7), buffer (phosphate, acetate, citrate, and histidine), and buffer concentration (20 mM and 50 mM). This method employed a weight-based procedure to interpret complex data sets and to investigate critical key factors representing protein stability. The factors used were Tm, enthalpy, and relative helix contents which were obtained by DSC and Fourier Transform Infrared spectroscopy (FT-IR). Although the weights changed by three responses, objective functions from a set of experimental designs based on four buffers were highest in 20 mM acetate buffer at pH 3.6 among all 19 scenarios tested. Size exclusion chromatography (SEC) was adopted to investigate accelerated storage stability in order to optimize the pH value with susceptible stability since the low pH was not patient-compliant. Interestingly, relative helix contents and storage stability (monomer remaining) increased with pH and was the highest at pH 4.0. On the other hand, relative helix contents and thermodynamic stability decreased at pH 4.2 and 4.4, suggesting protein aggregation issues. Therefore, the optimized basal buffer system for the novel biobetter was proposed to be 20 mM acetate buffer at pH 3.8±0.2.

  12. 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.

  13. Modulation of involucrin and envelope competence in human keratinocytes by hydrocortisone, retinyl acetate, and growth arrest.

    PubMed

    Cline, P R; Rice, R H

    1983-07-01

    Involucrin accumulation and ionophore-assisted envelope formation, markers of keratinocyte differentiation, were found to be highly dependent on culture conditions in the malignant epidermal keratinocyte line, SCC-13, derived from a human squamous cell carcinoma. In confluent cultures, approximately one-half of the cells were competent to form envelopes when grown in medium without hydrocortisone or retinyl acetate supplementation. Addition of hydrocortisone to the medium during growth resulted in up to 90% competence, while addition of retinyl acetate instead resulted in as low as 10% competence. Hydrocortisone partially antagonized the effect of retinyl acetate when both agents were added together. Involucrin levels, measured by radioimmunoassay, were modulated essentially in parallel with envelope competence under the various conditions tested. When the cells were grown in medium supplemented with hydrocortisone, the levels shortly after confluence were over 50-fold higher than in sparse cultures. Regardless of hydrocortisone or retinyl acetate addition, less than 1% of the cells were competent in sparse cultures of growing cells, but up to 90% exhibited this property after growth arrest in serum-free medium containing hydrocortisone. High levels of competence were correlated with cessation of cell division but not with loss of colony-forming efficiency; under optimal conditions, two-thirds of the cells were capable of both envelope formation and colony initiation. Normal human epidermal cells showed a 4- to 5-fold increase in envelope competence from sparse to confluent culture but were insensitive to the suppressive effect of retinyl acetate. The results suggest that some potential differentiated character of malignant keratinocytes may be suppressed in vivo by physiological agents such as vitamin A.

  14. The Effects of pH on the Growth and Aspect Ratio of Chicken Egg White Lysozyme Crystals Prepared in Different Buffers

    NASA Technical Reports Server (NTRS)

    Gibson, U. J.; Horrell, E. E.; Kou, Y.; Pusey, Marc

    2000-01-01

    We have measured the nucleation and aspect ratio of CEWL crystals grown by vapor diffusion in acetate, butyrate, carbonate, succinate, and phosphate buffers in a range of pH spanning the pK(sub a) of these buffers. The nucleation numbers drop off significantly in the vicinity of pK(sub a) for each of the buffers except the phosphate system, in which we used only the pH range around the second titration point(pK2). There is a concomitant increase in the sizes of the crystals. Some typical nucleation number results are shown. These data support and extend other observations. In addition, we have examined changes in aspect ratio which accompany the suppression of nucleation within each buffer system. The length of the face in the [001] direction was measured, and compared to the width of the (110) face in the [110] type directions. We find that while the aspect ratio of the crystals is affected by pH, it is dominated by a correlation with the size of the crystals. Small crystals are longer in the [0011 direction than crystals that are larger (higher pH within a buffer system). This relationship is found to hold independent of the choice of buffer. These results are consistent with those of Judge et al, who used a batch process which resulted in uniform sizing of crystals at each pH. In these experiments, we specifically avoid agitating the protein/salt buffer mixture when combining the two. This permits the formation of a range of sizes at a given pH. The results for a .05 M acetate 5% NaCl buffer are also shown. We will discuss these results in light of a growth model.

  15. Activation of AMP-Activated Protein Kinase and Stimulation of Energy Metabolism by Acetic Acid in L6 Myotube Cells.

    PubMed

    Maruta, Hitomi; Yoshimura, Yukihiro; Araki, Aya; Kimoto, Masumi; Takahashi, Yoshitaka; Yamashita, Hiromi

    2016-01-01

    Previously, we found that orally administered acetic acid decreased lipogenesis in the liver and suppressed lipid accumulation in adipose tissue of Otsuka Long-Evans Tokushima Fatty rats, which exhibit hyperglycemic obesity with hyperinsulinemia and insulin resistance. Administered acetic acid led to increased phosphorylation of AMP-activated protein kinase (AMPK) in both liver and skeletal muscle cells, and increased transcripts of myoglobin and glucose transporter 4 (GLUT4) genes in skeletal muscle of the rats. It was suggested that acetic acid improved the lipid metabolism in skeletal muscles. In this study, we examined the activation of AMPK and the stimulation of GLUT4 and myoglobin expression by acetic acid in skeletal muscle cells to clarify the physiological function of acetic acid in skeletal muscle cells. Acetic acid added to culture medium was taken up rapidly by L6 cells, and AMPK was phosphorylated upon treatment with acetic acid. We observed increased gene and protein expression of GLUT4 and myoglobin. Uptake of glucose and fatty acids by L6 cells were increased, while triglyceride accumulation was lower in treated cells compared to untreated cells. Furthermore, treated cells also showed increased gene and protein expression of myocyte enhancer factor 2A (MEF2A), which is a well-known transcription factor involved in the expression of myoglobin and GLUT4 genes. These results indicate that acetic acid enhances glucose uptake and fatty acid metabolism through the activation of AMPK, and increases expression of GLUT4 and myoglobin.

  16. Activation of AMP-Activated Protein Kinase and Stimulation of Energy Metabolism by Acetic Acid in L6 Myotube Cells.

    PubMed

    Maruta, Hitomi; Yoshimura, Yukihiro; Araki, Aya; Kimoto, Masumi; Takahashi, Yoshitaka; Yamashita, Hiromi

    2016-01-01

    Previously, we found that orally administered acetic acid decreased lipogenesis in the liver and suppressed lipid accumulation in adipose tissue of Otsuka Long-Evans Tokushima Fatty rats, which exhibit hyperglycemic obesity with hyperinsulinemia and insulin resistance. Administered acetic acid led to increased phosphorylation of AMP-activated protein kinase (AMPK) in both liver and skeletal muscle cells, and increased transcripts of myoglobin and glucose transporter 4 (GLUT4) genes in skeletal muscle of the rats. It was suggested that acetic acid improved the lipid metabolism in skeletal muscles. In this study, we examined the activation of AMPK and the stimulation of GLUT4 and myoglobin expression by acetic acid in skeletal muscle cells to clarify the physiological function of acetic acid in skeletal muscle cells. Acetic acid added to culture medium was taken up rapidly by L6 cells, and AMPK was phosphorylated upon treatment with acetic acid. We observed increased gene and protein expression of GLUT4 and myoglobin. Uptake of glucose and fatty acids by L6 cells were increased, while triglyceride accumulation was lower in treated cells compared to untreated cells. Furthermore, treated cells also showed increased gene and protein expression of myocyte enhancer factor 2A (MEF2A), which is a well-known transcription factor involved in the expression of myoglobin and GLUT4 genes. These results indicate that acetic acid enhances glucose uptake and fatty acid metabolism through the activation of AMPK, and increases expression of GLUT4 and myoglobin. PMID:27348124

  17. Activation of AMP-Activated Protein Kinase and Stimulation of Energy Metabolism by Acetic Acid in L6 Myotube Cells

    PubMed Central

    Maruta, Hitomi; Yoshimura, Yukihiro; Araki, Aya; Kimoto, Masumi; Takahashi, Yoshitaka; Yamashita, Hiromi

    2016-01-01

    Previously, we found that orally administered acetic acid decreased lipogenesis in the liver and suppressed lipid accumulation in adipose tissue of Otsuka Long-Evans Tokushima Fatty rats, which exhibit hyperglycemic obesity with hyperinsulinemia and insulin resistance. Administered acetic acid led to increased phosphorylation of AMP-activated protein kinase (AMPK) in both liver and skeletal muscle cells, and increased transcripts of myoglobin and glucose transporter 4 (GLUT4) genes in skeletal muscle of the rats. It was suggested that acetic acid improved the lipid metabolism in skeletal muscles. In this study, we examined the activation of AMPK and the stimulation of GLUT4 and myoglobin expression by acetic acid in skeletal muscle cells to clarify the physiological function of acetic acid in skeletal muscle cells. Acetic acid added to culture medium was taken up rapidly by L6 cells, and AMPK was phosphorylated upon treatment with acetic acid. We observed increased gene and protein expression of GLUT4 and myoglobin. Uptake of glucose and fatty acids by L6 cells were increased, while triglyceride accumulation was lower in treated cells compared to untreated cells. Furthermore, treated cells also showed increased gene and protein expression of myocyte enhancer factor 2A (MEF2A), which is a well-known transcription factor involved in the expression of myoglobin and GLUT4 genes. These results indicate that acetic acid enhances glucose uptake and fatty acid metabolism through the activation of AMPK, and increases expression of GLUT4 and myoglobin. PMID:27348124

  18. Micronized fibres affect in vitro fermentation under normal buffered and osmotic stress conditions using porcine inocula.

    PubMed

    Aumiller, T; Mosenthin, R; Rink, F; Hartung, K; Weiss, E

    2015-12-01

    In this in vitro study, the modified Hohenheim gas test was used to determine fermentation activity and bacterial composition of pig's faecal microbial inoculum, when fermenting a standard pig diet with varying levels of crude protein (CP; 20, 24 and 28% CP), and supplemented with one of three fibre sources manufactured by micronization treatment. These were wheat envelopes (MWE), pea fibre (MPF) and lupine fibre (MLF). For comparison, inulin was used. As intestinal bacteria have to cope with varying osmotic conditions in their ecosystem, fermentation was performed under normal buffered and osmotic stress conditions. After 24 h of fermentation, total gas production and ammonia production were measured. In addition, the effect of MWE and inulin on short-chain fatty acid (SCFA) production and numbers of total eubacteria, Lactobacillus spp., Bifidobacterium spp., Enterobacteriaceae, Enterococcus spp., Clostridium cluster XIVa and Clostridium cluster IV, were determined using quantitative real-time PCR. Under normal buffered conditions, supplementation of MWE resulted in increased (p < 0.05) SCFA, acetic, propionic and valerianic acid production at CP levels of 20 and 28%. There was an increase (p < 0.05) in ammonia production for the micronized supplements, and for MWE an increased (p < 0.05) branched-chain proportion was observed, possibly due to higher availability of protein for fermentation which was released during the micronization process. Osmotic stress conditions reduced (p < 0.05) total gas as well as total SCFA, acetic and propionic acid production for all treatments, while cell counts were increased (p < 0.05) for Bifidobacterium spp., Enterococcus spp. and Lactobacillus spp. Under normal buffered conditions in combination with 24 and 28% CP levels, lactobacilli were increased for MWE, compared to inulin (p < 0.05). In conclusion, micronized supplements such as MWE may beneficially modulate pigs' intestinal microbiota by increasing SCFA production in

  19. Synthesis of Gold Nanoparticles with Buffer-Dependent Variations of Size and Morphology in Biological Buffers

    NASA Astrophysics Data System (ADS)

    Ahmed, Syed Rahin; Oh, Sangjin; Baba, Rina; Zhou, Hongjian; Hwang, Sungu; Lee, Jaebeom; Park, Enoch Y.

    2016-02-01

    The demand for biologically compatible and stable noble metal nanoparticles (NPs) has increased in recent years due to their inert nature and unique optical properties. In this article, we present 11 different synthetic methods for obtaining gold nanoparticles (Au NPs) through the use of common biological buffers. The results demonstrate that the sizes, shapes, and monodispersity of the NPs could be varied depending on the type of buffer used, as these buffers acted as both a reducing agent and a stabilizer in each synthesis. Theoretical simulations and electrochemical experiments were performed to understand the buffer-dependent variations of size and morphology exhibited by these Au NPs, which revealed that surface interactions and the electrostatic energy on the (111) surface of Au were the determining factors. The long-term stability of the synthesized NPs in buffer solution was also investigated. Most NPs synthesized using buffers showed a uniquely wide range of pH stability and excellent cell viability without the need for further modifications.

  20. Synthesis of Gold Nanoparticles with Buffer-Dependent Variations of Size and Morphology in Biological Buffers.

    PubMed

    Ahmed, Syed Rahin; Oh, Sangjin; Baba, Rina; Zhou, Hongjian; Hwang, Sungu; Lee, Jaebeom; Park, Enoch Y

    2016-12-01

    The demand for biologically compatible and stable noble metal nanoparticles (NPs) has increased in recent years due to their inert nature and unique optical properties. In this article, we present 11 different synthetic methods for obtaining gold nanoparticles (Au NPs) through the use of common biological buffers. The results demonstrate that the sizes, shapes, and monodispersity of the NPs could be varied depending on the type of buffer used, as these buffers acted as both a reducing agent and a stabilizer in each synthesis. Theoretical simulations and electrochemical experiments were performed to understand the buffer-dependent variations of size and morphology exhibited by these Au NPs, which revealed that surface interactions and the electrostatic energy on the (111) surface of Au were the determining factors. The long-term stability of the synthesized NPs in buffer solution was also investigated. Most NPs synthesized using buffers showed a uniquely wide range of pH stability and excellent cell viability without the need for further modifications.

  1. Conversion to eslicarbazepine acetate monotherapy

    PubMed Central

    French, Jacqueline; Jacobson, Mercedes P.; Pazdera, Ladislav; Gough, Mallory; Cheng, Hailong; Grinnell, Todd; Blum, David

    2016-01-01

    Objective: To assess the efficacy and safety of eslicarbazepine acetate (ESL) monotherapy. Methods: This post hoc pooled analysis of 2 randomized double-blind studies (093-045 and -046) included adults with partial-onset seizures medically uncontrolled by 1 or 2 antiepileptic drugs (AEDs). Following the baseline period (8 weeks), eligible patients were randomized 2:1 to receive ESL 1,600 mg or 1,200 mg once daily for 18 weeks; the primary endpoint was study exit by meeting predefined exit criteria (signifying worsening seizure control). In each study, treatment was considered effective if the upper 95% confidence limit for exit rate was lower than the historical control threshold (65.3%). Results: Pooled exit rates were as follows: ESL 1,600 mg = 20.6% (95% confidence interval: 15.6%–26.8%); ESL 1,200 mg = 30.8% (23.0%–40.5%). Use of 2 baseline AEDs or rescue medication, US location, epilepsy duration ≥20 years, and higher maximum baseline seizure frequency were associated with higher exit risks. Median percent reductions in standardized seizure frequency between baseline and the 18-week double-blind period were as follows: ESL 1,600 mg = 43.2%; ESL 1,200 mg = 35.7%; baseline carbamazepine use was associated with smaller reductions. Safety profiles were similar between ESL doses. Conclusions: Exit rates for ESL monotherapy (1,600 mg and 1,200 mg once daily) were lower than the historical control threshold, irrespective of baseline AED use and region, with no additional safety concerns identified. Clinical factors and location clearly influence treatment responses in conversion-to-monotherapy trials. Classification of evidence: This pooled analysis provides Class IV evidence that for adults with medically uncontrolled partial-onset seizures, ESL monotherapy is well tolerated and effective. PMID:26911639

  2. Intravitreal injection of octreotide acetate.

    PubMed

    Robertson, J E; Westra, I; Woltering, E A; Winthrop, K L; Barrie, R; O'Dorisio, T M; Holmes, D

    1997-04-01

    This study was conducted to determine the feasibility of injecting the somatostatin analogue, octreotide acetate (OA), into the vitreous cavity. Previous work suggests that octreotide effectively inhibits angiogenesis in vitro, thus its use in vivo may slow the progression of proliferative eye disease. Fifty micrograms of aqueous OA in 50 microliters aqueous solution was injected into the mid-vitreous of kitten eyes (n = 6), and OA levels were monitored over 4 days. A long-acting release form of octreotide (OA-LAR) was also injected into the mid-vitreous of rabbit eyes at doses of 0.36 (n = 16), 1.1 (n = 1), 2.1 (n = 1), 4.05 (n = 1), 8.2 (n = 1), and 36 mg (n = 3) in solution; and octreotide concentrations were measured at various time points over 42 days. OA concentrations were determined by a highly specific radioimmunoassay. Aqueous octreotide was eliminated rapidly (t1/2 = 16 hours) from the vitreous of the kitten eye, with only negligible amounts recoverable 4 days post-injection. In the long-acting form, OA in the rabbit eye reached peak levels at 28 days. By 42 days, OA levels had declined to the 14-day level. Doses of OA-LAR of 1.1 mg or less produced no gross evidence of clinical toxicity and elicited no grossly visible ocular side effects. Doses greater than 1.1 mg produced significant toxicity, including cataracts and rubeosis. The 28-day peak release for long-acting OA implies that monthly intravitreal injections could provide continual high levels of OA. Intravitreal injection of long-acting OA provides sustained, high concentrations of drug, and deserves further study as a potential treatment of proliferative eye diseases.

  3. 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 (λ = 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.

  4. Analysis of acrylamido-buffers for isoelectric focusing by capillary zone electrophoresis.

    PubMed

    Righetti, P G; Ettori, C; Chiari, M

    1991-01-01

    Immobilized pH gradients use a series of weak acrylamido acids and bases (Immobiline) to create a pH gradient along the separation axis. These buffers can be degraded in water by two mechanisms: (i) hydrolysis of the amido bond, with generation of free acrylic acid and either an amino acid or a diamine; (ii) autopolymerization to oligomers and/or n-mers. In order to check for these degradation products, different capillary zone electrophoresis systems for analysis of all Immobilines have been devised. The acidic compounds are resolved in 100 mM acetate, pH 4.0, whereas the alkaline Immobilines are separated in 50 mM phosphate buffer, pH 7.7 (or pH 7.2 for the weaker species). Polymers of alkaline Immobilines are resolved in 50 mM phosphate buffer, pH 2.5, in 1% Ficoll-400. All Immobilines are detected underivatized, by their adsorption at 214 or 254 nm. A calibration curve has been constructed for quantification of acrylic acid contamination. As little as 1 mol% of acrylic acid contamination in Immobiline solutions can be detected, with a sensitivity limit below 0.2 mM (at the injection port). PMID:2050100

  5. Evaluating the effects of buffer conditions and extremolytes on thermostability of granulocyte colony-stimulating factor using high-throughput screening combined with design of experiments.

    PubMed

    Ablinger, Elisabeth; Hellweger, Monika; Leitgeb, Stefan; Zimmer, Andreas

    2012-10-15

    In this study, we combined a high-throughput screening method, differential scanning fluorimetry (DSF), with design of experiments (DoE) methodology to evaluate the effects of several formulation components on the thermostability of granulocyte colony stimulating factor (G-CSF). First we performed a primary buffer screening where we tested thermal stability of G-CSF in different buffers, pH values and buffer concentrations. The significance of each factor and the two-way interactions between them were studied by multivariable regression analysis. pH was identified as most critical factor regarding thermal stability. The most stabilizing buffer, sodium glutamate, and sodium acetate were determined for further investigations. Second we tested the effect of 6 naturally occurring extremolytes (trehalose, sucrose, ectoine, hydroxyectoine, sorbitol, mannitol) on the thermal stability of G-CSF, using a central composite circumscribed design. At low pH (3.8) and low buffer concentration (5 mM) all extremolytes led to a significant increase in thermal stability except the addition of ectoine which resulted in a strong destabilization of G-CSF. Increasing pH and buffer concentration led to an increase in thermal stability with all investigated extremolytes. The described systematic approach allowed to create a ranking of stabilizing extremolytes at different buffer conditions.

  6. 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.

  7. Wintering bird response to fall mowing of herbaceous buffers

    USGS Publications Warehouse

    Blank, P.J.; Parks, J.R.; Dively, G.P.

    2011-01-01

    Herbaceous buffers are strips of herbaceous vegetation planted between working agricultural land and streams or wetlands. Mowing is a common maintenance practice to control woody plants and noxious weeds in herbaceous buffers. Buffers enrolled in Maryland's Conservation Reserve Enhancement Program (CREP) cannot be mowed during the primary bird nesting season between 15 April and 15 August. Most mowing of buffers in Maryland occurs in late summer or fall, leaving the vegetation short until the following spring. We studied the response of wintering birds to fall mowing of buffers. We mowed one section to 10-15 cm in 13 buffers and kept another section unmowed. Ninety-two percent of birds detected in buffers were grassland or scrub-shrub species, and 98% of all birds detected were in unmowed buffers. Total bird abundance, species richness, and total avian conservation value were significantly greater in unmowed buffers, and Savannah Sparrows (Passerculus sandwichensis), Song Sparrows (Melospiza melodia), and White-throated Sparrows (Zonotrichia albicollis) were significantly more abundant in unmowed buffers. Wintering bird use of mowed buffers was less than in unmowed buffers. Leaving herbaceous buffers unmowed through winter will likely provide better habitat for wintering birds. ?? 2011 by the Wilson Ornithological Society.

  8. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture.

    PubMed

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

    2015-09-18

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

  9. Estimating the buffer capacity of forest soils

    SciTech Connect

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

    1985-11-01

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

  10. Influence of organic buffers on bacteriocin production by Streptococcus thermophilus ST110.

    PubMed

    Somkuti, George A; Gilbreth, Stefanie E

    2007-08-01

    The effect of the organic buffer salts MES, MOPS, and PIPES on the growth of S. thermophilus ST110, medium pH, and accumulation of the antipediococcal bacteriocin thermophilin 110 were evaluated in whey permeate media over a period of 24 h. In nonbuffered medium, thermophilin 110 production at 37 degrees C paralleled the growth of S. thermophilus ST110 and reached a maximum after 8-10 h. Addition of organic buffer salts decreased the drop in medium pH and resulted in increased biomass (dry cells; microg/mL) and higher yields of thermophilin 110 (units/microg cells). The best results were obtained by the addition of 1% (w/v) MES to the medium, which reduced the pH drop to 1.8 units after 10 h of growth (compared to 2.3 pH units in the control) and resulted in a 1.5-fold increase in cell mass (495 microg/mL) and a 7-fold increase in thermophilin 110 yield (77 units/microg dry cells) over the control. The results showed that whey permeate-based media may be suitable for producing large amounts of thermophilin 110 needed for controlling spoilage pediococci in industrial wine and beer fermentations.

  11. Fragrance material review on 3-phenylpropyl acetate.

    PubMed

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

    2012-09-01

    A toxicologic and dermatologic review of 3-phenylpropyl acetate when used as a fragrance ingredient is presented. 3-Phenylpropyl 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 3-phenylpropyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, skin sensitization, and toxicokinetics 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.

  12. Fragrance material review on anisyl acetate.

    PubMed

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

    2012-09-01

    A toxicologic and dermatologic review of anisyl acetate when used as a fragrance ingredient is presented. Anisyl 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 anisyl acetate were evaluated, then summarized, and includes: physical properties, skin irritation, skin sensitization, elicitation, and phototoxicity 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.

  13. Fragrance material review on piperonyl acetate.

    PubMed

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

    2012-09-01

    A toxicologic and dermatologic review of piperonyl acetate when used as a fragrance ingredient is presented. Piperonyl 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 piperonyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, toxicokinetics, and genotoxicity 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.

  14. Fragrance material review on 2-phenylpropyl acetate.

    PubMed

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

    2012-09-01

    A toxicologic and dermatologic review of 2-phenylpropyl acetate when used as a fragrance ingredient is presented. 2-Phenylpropyl 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 2-phenylpropyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, and skin sensitization 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.

  15. 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.

  16. 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...

  17. The erosion kinetics of conventional and resin-modified glass-ionomer luting cements in acidic buffer solutions.

    PubMed

    Hazar-Yoruc, Binnaz; Bavbek, Andac Barkin; Özcan, Mutlu

    2012-01-01

    This study investigated the erosion kinetics of conventional and resin-modified glass-ionomer luting cements in acidic buffer solutions as a function of time. Disc shaped specimens were prepared from conventional (Ketac-Cem: KTC) and resin-modified glass ionomer cements (Fuji Plus: FP) and immersed in three acidic buffer solutions (0.01 M) namely, acetic acid/sodium acetate (AA(B)), lactic acid/sodium lactate (LA(B)) and citric acid/sodium citrate (CA(B)) with a constant pH of 4.1 and stored for 1, 8, 24, 48, 80, 120 and 168 h. F concentration was determined using ion-specific electrode. Si, Ca and Al concentrations were determined by atomic absorption spectroscopy. Ca, Al, Si and F solubility rates in both FP and KTC were the highest in CA(B) solution. The erosion rates of both FP and KTC in all buffer solutions increased as a function of immersion time. The amount of F eluted from FP was more than that of KTC. The total amount of elements released from FP was less than KTC in all solutions. PMID:23207217

  18. Retention of ionisable compounds on high-performance liquid chromatography. XV. Estimation of the pH variation of aqueous buffers with the change of the acetonitrile fraction of the mobile phase.

    PubMed

    Subirats, Xavier; Bosch, Elisabeth; Rosés, Martí

    2004-12-01

    The most commonly used mobile phases in reversed-phase high-performance liquid chromatography (RP-HPLC) are hydro-organic mixtures of an aqueous buffer and an organic modifier. The addition of this organic solvent to buffered aqueous solutions involves a variation of the buffer properties (pH and buffer capacity). In this paper, the pH variation is studied for acetic acid-acetate, phosphoric acid-dihydrogenphosphate-hydrogenphosphate, citric acid-dihydrogencitrate-citrate, and ammonium-ammonia buffers. The proposed equations allow pH estimation of acetonitrile-water buffered mobile phases up to 60% (v/v) of organic modifier and initial aqueous buffer concentrations between 0.001 and 0.1 mol L(-1), from the initial aqueous pH. The estimated pH variation of the mobile phase and the pKa variation of the analytes allow us to predict the degree of ionisation of the analytes and from this and analyte hydrophobicities, to interpret the relative retention and separation of analyte mixtures.

  19. Acetate limitation and nitrite accumulation during denitrification

    SciTech Connect

    Oh, J.; Silverstein, J.

    1999-03-01

    Nitrite accumulated in denitrifying activated sludge mixed liquor when the carbon and electron source, acetate, was limited. If acetate was added to obtain a carbon-to-nitrogen (C:N) ratio in the range of 2:1 to 3:1, nitrate was completely consumed at the same rate with no nitrite accumulation, indicating that nitrate concentration controlled the respiration rate as long as sufficient substrate was present. However, when acetate was reduced to a C:N ratio of 1:1, while nitrate continued to be consumed, > 50% of the initial nitrate-nitrogen accumulated as nitrite and 29% persisted as nitrite throughout an endogenous denitrification period of 8--9 h. While nitrite accumulated during acetate-limited denitrification, the specific nitrate reduction rate increased significantly compared with the rate when excess acetate was provided as follows: 0.034 mg-NO{sub 3}-N/mg-mixed liquid volatile suspended solids/h versus 0.023 mg-NO{sub 3}-N/mg-mixed liquid volatile suspended solids/h, respective. This may be explained by nitrate respiration out-competing nitrite respiration for limited acetate electrons. Complete restoration of balanced denitrification and elimination of nitrite accumulation during denitrification required several weeks after the C:N ratio was increased back to 2:1.

  20. Lack of Buffering by Composites Promotes Shift to More Cariogenic Bacteria.

    PubMed

    Nedeljkovic, I; De Munck, J; Slomka, V; Van Meerbeek, B; Teughels, W; Van Landuyt, K L

    2016-07-01

    Secondary caries (SC) remains a very important problem with composite restorations. The objectives of this study were to test the acid-buffering ability of several restorative materials and to evaluate whether buffering of the restorative material has an impact on the microbial composition of the biofilm. Disk-shaped specimens of conventional composite, composite with surface prereacted glass-ionomer filler particles (so-called giomer), glass-ionomer cement (GIC), amalgam, and hydroxyapatite (HAp) (control) were exposed to aqueous solutions with pH 4, 5, 6, and 7 and to the medium containing bacteria-produced acids, and pH changes were recorded over several days. Next, material specimens were immersed in bacterial growth medium with pH adjusted to 5. After a 24-h incubation, the extracts were collected and inoculated with a cariogenic (Streptococcus mutans) and a noncariogenic (Streptococcus sanguinis) species. The bacterial growth was monitored both in a single-species model by spectrophotometry and in a dual-species model by viability quantitative polymerase chain reaction. Amalgam and HAp showed the strongest acid-buffering ability, followed by the GIC and the giomer, while the conventional composite did not exhibit any buffering capacity. Furthermore, due to the lack of acid-buffering abilities, composite was not able to increase the pH of the medium (pH 5), which, in the absence of antibacterial properties, allowed the growth of S. mutans, while the growth of S. sanguinis, a less aciduric species, was completely inhibited. A similar effect was observed when bacteria were cultured together: there was a higher percentage of S. mutans and lower percentage of S. sanguinis with the conventional composite than with other materials and HAp. In conclusion, conventional composites lack the ability to increase the local pH, which leads to the outgrowth of more acidogenic/aciduric bacteria and higher cariogenicity of the biofilm. Together with lack of antibacterial

  1. A Review of Effectiveness of Riparian Buffers in Agricultural Areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There has been growing recognition of the importance of riparian buffers between agricultural fields and waterbodies in recent years. Riparian buffers play an important role in mitigating the impacts of land use activities on water quality and aquatic ecosystems. Riparian buffer systems have been st...

  2. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Boundary pillars and buffer zones. 3931... EXPLORATION AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  3. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Boundary pillars and buffer zones. 3931... EXPLORATION AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  4. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Boundary pillars and buffer zones. 3931... EXPLORATION AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  5. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Boundary pillars and buffer zones. 3931... AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones. (a... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  6. Selective Isolation of Bacillus sphaericus from Soil by Use of Acetate as the Only Major Source of Carbon

    PubMed Central

    Massie, Julie; Roberts, Graham; White, Peter J.

    1985-01-01

    A simple chemically defined medium containing sodium acetate (37 or 74 mM) as the only major source of carbon was inoculated with soil from various locations. The bacteria which grew most rapidly at 30°C were almost entirely strains of Bacillus sphaericus and Arthrobacter species. Pasteurization of the soils made the medium selective for B. sphaericus. Several new strains were isolated, and the peptidoglycans of their cell walls were examined. PMID:16346815

  7. Deconvoluting the effects of buffer salt concentration in hydrophilic interaction chromatography on a zwitterionic stationary phase.

    PubMed

    West, Caroline; Auroux, Emeline

    2016-08-26

    Quantitative structure-retention relationships (QSRRs) furnish a detailed and reliable description of the role and extent of different molecular interactions that can be established between the analytes and the chromatographic system. Among QSRRs, the solvation parameter model using Abraham descriptors has gained acceptance as a general tool to explore the factors affecting retention in chromatographic systems. We have previously shown how a modified version of the solvation parameter model, with two extra terms to take account of interactions occurring with ionic and ionizable species (with positive and/or negative charges), could be applied to the characterization of hydrophilic interaction chromatographic (HILIC) systems. In the present study, we will show how this methodology can be used to evaluate the effects of increasing buffer salt concentration on retention and separation in a HILIC system. A commercial stationary phase possessing a sulfobetaine zwitterionic bonded ligand (Nucleodur HILIC) was used with a mobile phase composed of 80% acetonitrile and 20% pwwH4 ammonium acetate buffer, with aqueous buffer concentrations varying from 10 to 100mM, resulting in overall concentrations ranging from 2 to 20mM in the mobile phase. Retention factors were measured for a selection of 76 probe analytes. The chosen compounds are small molecules presenting a wide diversity of molecular structures and are relevant to biomedical and pharmaceutical applications. The QSRR models obtained allow for a rationalization of the interactions contributing to retention and separation in the HILIC system considered and shed some light on the effect of varying buffer salt concentration, namely the progressive transition from ion-exchange and electrostatic-repulsion mechanisms to hydrophilic partitioning. PMID:27475992

  8. Characterization of a recombinant flocculent Saccharomyces cerevisiae strain that co-ferments glucose and xylose: II. influence of pH and acetic acid on ethanol production.

    PubMed

    Matsushika, Akinori; Sawayama, Shigeki

    2012-12-01

    The inhibitory effects of pH and acetic acid on the co-fermentation of glucose and xylose in complex medium by recombinant flocculent Saccharomyces cerevisiae MA-R4 were evaluated. In the absence of acetic acid, the fermentation performance of strain MA-R4 was similar between pH 4.0-6.0, but was negatively affected at pH 2.5. The addition of acetic acid to batch cultures resulted in negligible inhibition of several fermentation parameters at pH 6.0, whereas the interactive inhibition of pH and acetic acid on the maximum cell and ethanol concentrations, and rates of sugar consumption and ethanol production were observed at pH levels below 5.4. The inhibitory effect of acetic acid was particularly marked for the consumption rate of xylose, as compared with that of glucose. With increasing initial acetic acid concentration, the ethanol yield slightly increased at pH 5.4 and 6.0, but decreased at pH values lower than 4.7. Notably, ethanol production was nearly completely inhibited under low pH (4.0) and high acetic acid (150-200 mM) conditions. Together, these results indicate that the inhibitory effects of acetic acid and pH on ethanol fermentation by MA-R4 are highly synergistic, although the inhibition can be reduced by increasing the medium pH. PMID:23076570

  9. Isolation of acetic, propionic and butyric acid-forming bacteria from biogas plants.

    PubMed

    Cibis, Katharina Gabriela; Gneipel, Armin; König, Helmut

    2016-02-20

    In this study, acetic, propionic and butyric acid-forming bacteria were isolated from thermophilic and mesophilic biogas plants (BGP) located in Germany. The fermenters were fed with maize silage and cattle or swine manure. Furthermore, pressurized laboratory fermenters digesting maize silage were sampled. Enrichment cultures for the isolation of acid-forming bacteria were grown in minimal medium supplemented with one of the following carbon sources: Na(+)-dl-lactate, succinate, ethanol, glycerol, glucose or a mixture of amino acids. These substrates could be converted by the isolates to acetic, propionic or butyric acid. In total, 49 isolates were obtained, which belonged to the phyla Firmicutes, Tenericutes or Thermotogae. According to 16S rRNA gene sequences, most isolates were related to Clostridium sporosphaeroides, Defluviitoga tunisiensis and Dendrosporobacter quercicolus. Acetic, propionic or butyric acid were produced in cultures of isolates affiliated to Bacillus thermoamylovorans, Clostridium aminovalericum, Clostridium cochlearium/Clostridium tetani, C. sporosphaeroides, D. quercicolus, Proteiniborus ethanoligenes, Selenomonas bovis and Tepidanaerobacter sp. Isolates related to Thermoanaerobacterium thermosaccharolyticum produced acetic, butyric and lactic acid, and isolates related to D. tunisiensis formed acetic acid. Specific primer sets targeting 16S rRNA gene sequences were designed and used for real-time quantitative PCR (qPCR). The isolates were physiologically characterized and their role in BGP discussed.

  10. Sequential injection redox or acid-base titration for determination of ascorbic acid or acetic acid.

    PubMed

    Lenghor, Narong; Jakmunee, Jaroon; Vilen, Michael; Sara, Rolf; Christian, Gary D; Grudpan, Kate

    2002-12-01

    Two sequential injection titration systems with spectrophotometric detection have been developed. The first system for determination of ascorbic acid was based on redox reaction between ascorbic acid and permanganate in an acidic medium and lead to a decrease in color intensity of permanganate, monitored at 525 nm. A linear dependence of peak area obtained with ascorbic acid concentration up to 1200 mg l(-1) was achieved. The relative standard deviation for 11 replicate determinations of 400 mg l(-1) ascorbic acid was 2.9%. The second system, for acetic acid determination, was based on acid-base titration of acetic acid with sodium hydroxide using phenolphthalein as an indicator. The decrease in color intensity of the indicator was proportional to the acid content. A linear calibration graph in the range of 2-8% w v(-1) of acetic acid with a relative standard deviation of 4.8% (5.0% w v(-1) acetic acid, n=11) was obtained. Sample throughputs of 60 h(-1) were achieved for both systems. The systems were successfully applied for the assays of ascorbic acid in vitamin C tablets and acetic acid content in vinegars, respectively.

  11. The Fate of Acetic Acid during Glucose Co-Metabolism by the Spoilage Yeast Zygosaccharomyces bailii

    PubMed Central

    Rodrigues, Fernando; Sousa, Maria João; Ludovico, Paula; Santos, Helena; Côrte-Real, Manuela; Leão, Cecília

    2012-01-01

    Zygosaccharomyces bailii is one of the most widely represented spoilage yeast species, being able to metabolise acetic acid in the presence of glucose. To clarify whether simultaneous utilisation of the two substrates affects growth efficiency, we examined growth in single- and mixed-substrate cultures with glucose and acetic acid. Our findings indicate that the biomass yield in the first phase of growth is the result of the weighted sum of the respective biomass yields on single-substrate medium, supporting the conclusion that biomass yield on each substrate is not affected by the presence of the other at pH 3.0 and 5.0, at least for the substrate concentrations examined. In vivo 13C-NMR spectroscopy studies showed that the gluconeogenic pathway is not operational and that [2−13C]acetate is metabolised via the Krebs cycle leading to the production of glutamate labelled on C2, C3 and C4. The incorporation of [U-14C]acetate in the cellular constituents resulted mainly in the labelling of the protein and lipid pools 51.5% and 31.5%, respectively. Overall, our data establish that glucose is metabolised primarily through the glycolytic pathway, and acetic acid is used as an additional source of acetyl-CoA both for lipid synthesis and the Krebs cycle. This study provides useful clues for the design of new strategies aimed at overcoming yeast spoilage in acidic, sugar-containing food environments. Moreover, the elucidation of the molecular basis underlying the resistance phenotype of Z. bailii to acetic acid will have a potential impact on the improvement of the performance of S. cerevisiae industrial strains often exposed to acetic acid stress conditions, such as in wine and bioethanol production. PMID:23285028

  12. Acetate Production from Oil under Sulfate-Reducing Conditions in Bioreactors Injected with Sulfate and Nitrate

    PubMed Central

    Callbeck, Cameron M.; Agrawal, Akhil

    2013-01-01

    Oil production by water injection can cause souring in which sulfate in the injection water is reduced to sulfide by resident sulfate-reducing bacteria (SRB). Sulfate (2 mM) in medium injected at a rate of 1 pore volume per day into upflow bioreactors containing residual heavy oil from the Medicine Hat Glauconitic C field was nearly completely reduced to sulfide, and this was associated with the generation of 3 to 4 mM acetate. Inclusion of 4 mM nitrate inhibited souring for 60 days, after which complete sulfate reduction and associated acetate production were once again observed. Sulfate reduction was permanently inhibited when 100 mM nitrate was injected by the nitrite formed under these conditions. Pulsed injection of 4 or 100 mM nitrate inhibited sulfate reduction temporarily. Sulfate reduction resumed once nitrate injection was stopped and was associated with the production of acetate in all cases. The stoichiometry of acetate formation (3 to 4 mM formed per 2 mM sulfate reduced) is consistent with a mechanism in which oil alkanes and water are metabolized to acetate and hydrogen by fermentative and syntrophic bacteria (K. Zengler et al., Nature 401:266–269, 1999), with the hydrogen being used by SRB to reduce sulfate to sulfide. In support of this model, microbial community analyses by pyrosequencing indicated SRB of the genus Desulfovibrio, which use hydrogen but not acetate as an electron donor for sulfate reduction, to be a major community component. The model explains the high concentrations of acetate that are sometimes found in waters produced from water-injected oil fields. PMID:23770914

  13. Buffer for a gamma-insensitive optical sensor with gas and a buffer assembly

    DOEpatents

    Kruger, Hans W.

    1994-01-01

    A buffer assembly for a gamma-insensitive gas avalanche focal plane array operating in the ultra-violet/visible/infrared energy wavelengths and using a photocathode and an avalanche gas located in a gap between an anode and the photocathode. The buffer assembly functions to eliminate chemical compatibility between the gas composition and the materials of the photocathode. The buffer assembly in the described embodiment is composed of two sections, a first section constructed of glass honeycomb under vacuum and a second section defining a thin barrier film or membrane constructed, for example, of Al and Be, which is attached to and supported by the honeycomb. The honeycomb section, in turn, is supported by and adjacent to the photocathode.

  14. 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.

  15. Synthetic laser medium

    DOEpatents

    Stokowski, Stanley E.

    1989-01-01

    A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chormium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

  16. Synthetic laser medium

    DOEpatents

    Stokowski, S.E.

    1987-10-20

    A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chromium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

  17. 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.

  18. 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.

  19. Analysis of a hybrid, unidirectional buffer strip laminate

    NASA Technical Reports Server (NTRS)

    Dharani, L. R.; Goree, J. G.

    1983-01-01

    A method of analysis capable of predicting accurately the fracture behavior of a unidirectional composite laminate containing symmetrically placed buffer strips is presented. As an example, for a damaged graphite/epoxy laminate, the results demonstrate the manner in which to select the most efficient combination of buffer strip properties necessary to inhibit crack growth. Ultimate failure of the laminate after crack arrest can occur under increasing load either by continued crack extension through the buffer strips or the crack can jump the buffer strips. For some typical hybrid materials it is found that a buffer strip spacing-to-width ratio of about four to one is the most efficient.

  20. Analysis of a hybrid-undirectional buffer strip laminate

    NASA Technical Reports Server (NTRS)

    Dharani, L. R.; Goree, J. G.

    1983-01-01

    A method of analysis capable of predicting accurately the fracture behavior of a unidirectional composite laminate containing symmetrically placed buffer strips is presented. As an example, for a damaged graphite/epoxy laminate, the results demonstrate the manner in which to select the most efficient combination of buffer strip properties necessary to inhibit crack growth. Ultimate failure of the laminate after the arrest can occur under increasing load either by continued crack extension through the buffer strips or the crack can jump the buffer strips. For some typical hybrid materials it is found that a buffer strip spacing to width ratio of about four to one is the most efficient.

  1. k(+)-buffer: An Efficient, Memory-Friendly and Dynamic k-buffer Framework.

    PubMed

    Vasilakis, Andreas-Alexandros; Papaioannou, Georgios; Fudos, Ioannis

    2015-06-01

    Depth-sorted fragment determination is fundamental for a host of image-based techniques which simulates complex rendering effects. It is also a challenging task in terms of time and space required when rasterizing scenes with high depth complexity. When low graphics memory requirements are of utmost importance, k-buffer can objectively be considered as the most preferred framework which advantageously ensures the correct depth order on a subset of all generated fragments. Although various alternatives have been introduced to partially or completely alleviate the noticeable quality artifacts produced by the initial k-buffer algorithm in the expense of memory increase or performance downgrade, appropriate tools to automatically and dynamically compute the most suitable value of k are still missing. To this end, we introduce k(+)-buffer, a fast framework that accurately simulates the behavior of k-buffer in a single rendering pass. Two memory-bounded data structures: (i) the max-array and (ii) the max-heap are developed on the GPU to concurrently maintain the k-foremost fragments per pixel by exploring pixel synchronization and fragment culling. Memory-friendly strategies are further introduced to dynamically (a) lessen the wasteful memory allocation of individual pixels with low depth complexity frequencies, (b) minimize the allocated size of k-buffer according to different application goals and hardware limitations via a straightforward depth histogram analysis and (c) manage local GPU cache with a fixed-memory depth-sorting mechanism. Finally, an extensive experimental evaluation is provided demonstrating the advantages of our work over all prior k-buffer variants in terms of memory usage, performance cost and image quality. PMID:26357252

  2. k(+)-buffer: An Efficient, Memory-Friendly and Dynamic k-buffer Framework.

    PubMed

    Vasilakis, Andreas-Alexandros; Papaioannou, Georgios; Fudos, Ioannis

    2015-06-01

    Depth-sorted fragment determination is fundamental for a host of image-based techniques which simulates complex rendering effects. It is also a challenging task in terms of time and space required when rasterizing scenes with high depth complexity. When low graphics memory requirements are of utmost importance, k-buffer can objectively be considered as the most preferred framework which advantageously ensures the correct depth order on a subset of all generated fragments. Although various alternatives have been introduced to partially or completely alleviate the noticeable quality artifacts produced by the initial k-buffer algorithm in the expense of memory increase or performance downgrade, appropriate tools to automatically and dynamically compute the most suitable value of k are still missing. To this end, we introduce k(+)-buffer, a fast framework that accurately simulates the behavior of k-buffer in a single rendering pass. Two memory-bounded data structures: (i) the max-array and (ii) the max-heap are developed on the GPU to concurrently maintain the k-foremost fragments per pixel by exploring pixel synchronization and fragment culling. Memory-friendly strategies are further introduced to dynamically (a) lessen the wasteful memory allocation of individual pixels with low depth complexity frequencies, (b) minimize the allocated size of k-buffer according to different application goals and hardware limitations via a straightforward depth histogram analysis and (c) manage local GPU cache with a fixed-memory depth-sorting mechanism. Finally, an extensive experimental evaluation is provided demonstrating the advantages of our work over all prior k-buffer variants in terms of memory usage, performance cost and image quality.

  3. Iodine--iodide reference electrode for potentiometric titrations of bases in acetic acid.

    PubMed

    Maccà, Carlo; Soldà, Lidia

    2002-03-01

    The suitability of the half-cell Pt/I2, KI in glacial acetic acid as reference electrode for potentiometric titrations of weak bases in the same medium was investigated. This electrode is easily prepared. It has been found very convenient in use and performing at least as well as the best electrodes used for the same purpose. Some phenomenological aspects of the behaviour of the above half-cell, of interest for the use as the reference electrode in the laboratory practice have been observed, that show important differences respect aqueous medium and other organic solvents.

  4. DNA microarray analyses of the long-term adaptive response of Escherichia coli to acetate and propionate.

    PubMed

    Polen, T; Rittmann, D; Wendisch, V F; Sahm, H

    2003-03-01

    In its natural environment, Escherichia coli is exposed to short-chain fatty acids, such as acetic acid or propionic acid, which can be utilized as carbon sources but which inhibit growth at higher concentrations. DNA microarray experiments revealed expression changes during exponential growth on complex medium due to the presence of sodium acetate or sodium propionate at a neutral external pH. The adaptive responses to acetate and propionate were similar and involved genes in three categories. First, the RNA levels for chemotaxis and flagellum genes increased. Accordingly, the expression of chromosomal fliC'-'lacZ and flhDC'-'lacZ fusions and swimming motility increased after adaptation to acetate or propionate. Second, the expression of many genes that are involved in the uptake and utilization of carbon sources decreased, indicating some kind of catabolite repression by acetate and propionate. Third, the expression of some genes of the general stress response increased, but the increases were more pronounced after short-term exposure for this response than for the adaptive response. Adaptation to propionate but not to acetate involved increased expression of threonine and isoleucine biosynthetic genes. The gene expression changes after adaptation to acetate or propionate were not caused solely by uncoupling or osmotic effects but represented specific characteristics of the long-term response of E. coli to either compound. PMID:12620868

  5. 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.

  6. Spacecraft optical disk recorder memory buffer control

    NASA Technical Reports Server (NTRS)

    Hodson, Robert F.

    1992-01-01

    The goal of this project is to develop an Application Specific Integrated Circuit (ASIC) for use in the control electronics of the Spacecraft Optical Disk Recorder (SODR). Specifically, this project is to design an extendable memory buffer controller ASIC for rate matching between a system Input/Output port and the SODR's device interface. The aforementioned goal can be partitioned into the following sub-goals: (1) completion of ASIC design and simulation (on-going via ASEE fellowship); (2) ASIC Fabrication (at ASIC manufacturer); and (3) ASIC Testing (NASA/LaRC, Christopher Newport University).

  7. Branch target buffer design and optimization

    NASA Technical Reports Server (NTRS)

    Perleberg, Chris H.; Smith, Alan J.

    1993-01-01

    Consideration is given to two major issues in the design of branch target buffers (BTBs), with the goal of achieving maximum performance for a given number of bits allocated to the BTB design. The first issue is BTB management; the second is what information to keep in the BTB. A number of solutions to these problems are reviewed, and various optimizations in the design of BTBs are discussed. Design target miss ratios for BTBs are developed, making it possible to estimate the performance of BTBs for real workloads.

  8. An optimized buffer controlled data compression system

    NASA Technical Reports Server (NTRS)

    Dosik, P. H.; Schwartz, M.

    1974-01-01

    The digital data compression system considered uses a buffer controlled aperture algorithm which minimizes the mean-squared error between the reconstructed receiver output and transmitter input. The data compression technique selected is based on the zero-order floating aperture prediction rule. It is assumed that the statistics of the input data are initially uniformly distributed, stationary, and first-order Markov. The problem is solved for stationary data. An approach is presented for extending the results to slowly varying uniformly distributed nonstationary Markov data.

  9. In vitro dissolution of proton-pump inhibitor products intended for paediatric and geriatric use in physiological bicarbonate buffer.

    PubMed

    Liu, Fang; Shokrollahi, Honaz

    2015-05-15

    Proton-pump inhibitor (PPI) products based on enteric coated multiparticulates are design to meet the needs of patients who cannot swallow tablets such as children and older adults. Enteric coated PPI preparations exhibit delays in in vivo absorption and onset of antisecretory effects, which is not reflected by the rapid in vitro dissolution in compendial pH 6.8 phosphate buffer commonly used for assessment of these products. A more representative and physiological medium, pH 6.8 mHanks bicarbonate buffer, was used in this study to evaluate the in vitro dissolution of enteric coated multiparticulate-based PPI products. Commercially available omeprazole, lansoprazole and esomeprazole products were subject to dissolution tests using USP-II apparatus in pH 4.5 phosphate buffer saline for 45 min (acid stage) followed by pH 6.8 phosphate buffer or pH 6.8 mHanks bicarbonate buffer. In pH 6.8 phosphate buffer, all nine tested products displayed rapid and comparable dissolution profiles meeting the pharmacopeia requirements for delayed release preparations. In pH 6.8 mHanks buffer, drug release was delayed and failed the pharmacopeia requirements from most enteric coated preparations. Despite that the same enteric polymer, methacrylic acid-ethyl acrylate copolymer (1:1), was applied to all commercial multiparticulate-based products, marked differences were observed between dissolution profiles of these preparations. The use of pH 6.8 physiological bicarbonate (mHanks) buffer can serve as a useful tool to provide realistic and discriminative in vitro release assessment of enteric coated PPI preparations and to assist rational formulation development of these products. PMID:25746736

  10. In vitro dissolution of proton-pump inhibitor products intended for paediatric and geriatric use in physiological bicarbonate buffer.

    PubMed

    Liu, Fang; Shokrollahi, Honaz

    2015-05-15

    Proton-pump inhibitor (PPI) products based on enteric coated multiparticulates are design to meet the needs of patients who cannot swallow tablets such as children and older adults. Enteric coated PPI preparations exhibit delays in in vivo absorption and onset of antisecretory effects, which is not reflected by the rapid in vitro dissolution in compendial pH 6.8 phosphate buffer commonly used for assessment of these products. A more representative and physiological medium, pH 6.8 mHanks bicarbonate buffer, was used in this study to evaluate the in vitro dissolution of enteric coated multiparticulate-based PPI products. Commercially available omeprazole, lansoprazole and esomeprazole products were subject to dissolution tests using USP-II apparatus in pH 4.5 phosphate buffer saline for 45 min (acid stage) followed by pH 6.8 phosphate buffer or pH 6.8 mHanks bicarbonate buffer. In pH 6.8 phosphate buffer, all nine tested products displayed rapid and comparable dissolution profiles meeting the pharmacopeia requirements for delayed release preparations. In pH 6.8 mHanks buffer, drug release was delayed and failed the pharmacopeia requirements from most enteric coated preparations. Despite that the same enteric polymer, methacrylic acid-ethyl acrylate copolymer (1:1), was applied to all commercial multiparticulate-based products, marked differences were observed between dissolution profiles of these preparations. The use of pH 6.8 physiological bicarbonate (mHanks) buffer can serve as a useful tool to provide realistic and discriminative in vitro release assessment of enteric coated PPI preparations and to assist rational formulation development of these products.

  11. Effect of selected dietary buffers upon utilization of concentrate- or roughage-based cattle diets: laboratory studies.

    PubMed

    Hall, M W; Thomas, E E

    1984-07-01

    Four chemical buffers were evaluated with in vitro rumen fermentation studies using both an 80% concentrate and a 50% roughage diet. Treatments included a positive control (PC), negative control (NC) and four buffered diets in which 500 mg of either CaHPO4, CaCO3, NaHCO3 or Na4P2O7 were added. The PC consisted of unbuffered diet with one part rumen fluid and four parts McDougall's artificial saliva. In the unbuffered NC and buffered treatments, three-fourths of the artificial saliva was replaced by iso-osmotic saline. In the concentrate-based diet, NaHCO3 and Na4P2O7 elevated (P less than .05) pH above the NC. Starch digestion and total VFA were increased (P less than .05) by NaHCO3 compared with the NC while the molar proportion of individual VFA was not altered. Tetrasodium pyrophosphate had no effect on starch digestion or total VFA, but did increase (P less than .05) the molar proportion of acetic acid. Regarding the 50% roughage diet, both NaHCO3 and Na4P2O7 elevated (P less than .05) starch and cellulose digestion and total VFA compared with the NC. Both NaHCO3 and Na4P2O7 increased (P less than .05) the molar proportion of acetate to equal that of the PC. Tetrasodium pyrophosphate decreased (P less than .05) apparent starch digestion compared with the NC, but increased (P less than .05) the molar proportion of acetate. Compared with the NC, CaHPO4 and Na4P2O7 increased the quantity of microbial alpha-amino N in both diets. Soluble P was highly correlated with microbial protein synthesis in both the concentrate- and roughage-based diets (.92 and .90, respectively).

  12. Substitution of carbonate buffer by water for IgG immobilization in enzyme linked immunosorbent assay.

    PubMed

    Shrivastav, Tulsidas G; Basu, Anupam; Kariya, Kiran P

    2003-01-01

    The first step of enzyme linked immunosorbent assay (ELISA), namely, adsorption of antigen or antibody to the plastic microtiter well plate, was studied as a function of insolubility of IgG in water. Immobilization efficiency was assessed in terms of number of wells coated per milliliter of primary antiserum. We have compared different coating/immobilization protocols, i.e., direct and indirect immobilization of primary antibody to the plastic microtiter well plate using carbonate buffer and phosphate buffer with glutaraldehyde. We have observed efficient coating when the immobilization of primary antibody through an immunobridge technique was performed, where water was used as a coating medium. It gave a higher number of wells coated per milliliter of anti-serum (primary or secondary) than other compared coating protocols and it allowed the use of serum (non-immune) and anti-serum (primary and secondary antibody) dilutions, avoiding the need for gamma-globulin purification from normal and immunized serum. PMID:12778971

  13. Acetic acid production from food wastes using yeast and acetic acid bacteria micro-aerobic fermentation.

    PubMed

    Li, Yang; He, Dongwei; Niu, Dongjie; Zhao, Youcai

    2015-05-01

    In this study, yeast and acetic acid bacteria strains were adopted to enhance the ethanol-type fermentation resulting to a volatile fatty acids yield of 30.22 g/L, and improve acetic acid production to 25.88 g/L, with food wastes as substrate. In contrast, only 12.81 g/L acetic acid can be obtained in the absence of strains. The parameters such as pH, oxidation reduction potential and volatile fatty acids were tested and the microbial diversity of different strains and activity of hydrolytic ferment were investigated to reveal the mechanism. The optimum pH and oxidation reduction potential for the acetic acid production were determined to be at 3.0-3.5 and -500 mV, respectively. Yeast can convert organic matters into ethanol, which is used by acetic acid bacteria to convert the organic wastes into acetic acid. The acetic acid thus obtained from food wastes micro-aerobic fermentation liquid could be extracted by distillation to get high-pure acetic acid.

  14. Acetylation of Starch with Vinyl Acetate in Imidazolium Ionic Liquids and Characterization of Acetate Distribution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch was acetylated with vinyl acetate in different 1-butyl-3-methylimidazolium (BMIM) salts as solvent in effort to produce starches with different acetylation patterns. Overall degree of substitution was much higher for basic anions such as acetate and dicyanimide (dca) than for neutral anions ...

  15. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... new uses subject to 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. 110-49-6) are subject to reporting under this section for the significant new...

  16. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... new uses subject to 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. 110-49-6) are subject to reporting under this section for the significant new...

  17. Electromembrane extraction and HPLC analysis of haloacetic acids and aromatic acetic acids in wastewater.

    PubMed

    Alhooshani, Khalid; Basheer, Chanbasha; Kaur, Jagjit; Gjelstad, Astrid; Rasmussen, Knut E; Pedersen-Bjergaard, Stig; Lee, Hian Kee

    2011-10-30

    For the first time, haloacetic acids and aromatic acetic acids were extracted from wastewater samples using electromembrane extraction (EME). A thin layer of toluene immobilized on the walls of a polypropylene membrane envelope served as an artificial supported liquid membrane (SLM). The haloacetic acids (HAAs) (chloroacetic acid, dichloroacetic acid, and trifluoroacetic acid) and aromatic acetic acids (phenylacetic acid and p-hydroxyphenylacetic acid) were extracted through the SLM and into an alkalized aqueous buffer solution. The buffer solution was located inside the membrane envelope. The electrical potential difference sustained over the membrane acted as the driving force for the transport of haloacetic acids into the membrane by electrokinetic migration. After extraction, the extracts were analyzed by high-performance liquid chromatography-ultraviolet detection. The detection limits were between 0.072 and 40.3 ng L(-1). The calibration plot linearity was in the range of 5 and 200 μg L(-1) while the correlation coefficients for the analytes ranged from 0.9932 to 0.9967. Relative recoveries were in the range of 87-106%. The extraction efficiency was found to be comparable to that of solid-phase extraction.

  18. Buffers in daphnid culture and bioassay

    SciTech Connect

    Keating, K.I.; Caffrey, P.B.; Dagbusan, B.C.

    1996-03-01

    When an algal diet is employed, or precipitation of dissolved inorganics during autoclaving is likely, or test circumstances introduce pH changes, addition of a buffer to daphnid culture or bioassay media is appropriate. Glycylglycine, employed in this research for 20 years, is unsuitable for general use because it required microbe-free cultures. In contrast, n-hydroxyethyl piperazine-n-2-propane sulfonic acid (HEPPSO) and N-2-hydroxyethyl piperazine-N{prime}-2-ethane sulfonic acid (HEPES) offer safe and effective pH control at 300 ppm for animals, 400 ppm for algae (weight excludes Na), with no requirement for microbe-free cultures. No negative effects on fecundity, monitored in both single and multigeneration tests, or on vigor, measured by acute bioassay performance, were observed. The 48-h LC50 for glycylglycine is approximately 4,500 ppm. No deaths occur at or below 10,000 ppm of either HEPES or HEPPSO. When bioassayed against zinc (as chloride), animals reared in cultures buffered by HEPES, HEPPSO, or glycylglycine and tested in unfed acute bioassays performed similarly, allowing 100% survival in 1,000 ppb in 48 h with an CL50 of approximately 1,750 ppb.

  19. Buffering Mechanism of the Atmospheric Oxidation Capacity

    NASA Astrophysics Data System (ADS)

    Lelieveld, J.; Gromov, S.; Pozzer, A.; Taraborrelli, D.

    2015-12-01

    Millions of tons pollutant and greenhouse gases per year are emitted and subsequently removed from the atmosphere through oxidation reactions. The oxidation products are typically more soluble or have a low vapor pressure so that they become subject to deposition processes. The atmospheric oxidation capacity is primarily maintained by hydroxyl (OH) radicals, which initiate reaction chains that can recycle or destroy OH. Key questions are if the oxidation capacity is affected by growing pollution emissions, to what extent it is buffered by OH recycling, and how regions with specific photochemical and pollution characteristics act together through atmospheric transport at a global scale. While previous generations atmospheric chemistry-transport models have discounted OH recycling with schemes that lumped or truncated reaction sequences, we present an approach that does justice to the intricate interactions between reactive carbon, nitrogen and oxygen species. This gives rise to a global buffering mechanism of the oxidation capacity that explains the observed small variability of methane and other gases that are removed by reaction with OH.

  20. Dynamic Protonation Equilibrium of Solvated Acetic Acid

    SciTech Connect

    Gu, Wei; Frigato, Tomaso; Straatsma, TP; Helms, Volkhard H.

    2007-04-13

    For the first time, the dynamic protonation equilibrium between an amino acid side chain analogue and bulk water as well as the diffusion properties of the excess proton were successfully reproduced through unbiased computer simulations. During a 50 ns Q-HOP MD simulation, two different regimes of proton transfer were observed. Extended phases of frequent proton swapping between acetic acid and nearby water were separated by phases where the proton freely diffuses in the simulation box until it is captured again by acetic acid. The pKa of acetic acid was calculated around 3.0 based on the relative population of protonated and deprotonated states and the diffusion coefficient of excess proton was computed from the average mean squared displacement in the simulation. Both calculated values agree well with the experimental measurements.

  1. Leuprolide acetate-induced generalized papular eruption.

    PubMed

    Burris, Katy; Ding, Catherine Y; Lim, Geoffrey F S

    2014-06-01

    Leuprolide acetate, a gonadotropin-releasing hormone agonist, is used in the treatment of prostate cancer. We report a unique case of a disseminated papular rash following leuprolide acetate injections in a 65-year-old man that shares clinical and histopathological features of papuloerythroderma of Ofuji. Leuprolide-induced papuloerythroderma, as well as a limited number of other disseminated cutaneous eruptions caused by this drug, is extremely rare, with only one case previously reported. Our case calls attention to this uncommon side effect in a commonly used hormonal therapy.

  2. 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.

  3. Enhanced sensitivity RNA gel loading buffer that enables efficient RNA separation on native gels.

    PubMed

    Gregg, Keqin; Zhou, Wenli; Ji, Wan; Davis, Sara

    2004-02-01

    RNA gel analysis is essential for quality assessment of RNA preparations for subsequent analysis such as microarrays and real-time PCRs. The routinely used standard electrophoresis of RNA through formaldehyde-containing agarose gels is not only labor-intensive and time-consuming, but also involves sizeable quantities of hazardous materials. Above all, it is not sensitive, requiring more than 1 microgram of RNA for the assay. Current gene expression profiling with microarrays and real-time PCR often involves limiting amounts of RNA. It is therefore important to have a more sensitive way to analyze RNA. Here we report an improved ethidium bromide-based RNA gel analysis system with our Superload buffer that increases sensitivity to 12.5 ng of total RNA and allows RNA analysis on a regular native Tris-acetate EDTA (TAE) agarose gel.

  4. High rates of [1-14C]acetate incorporation into the lipid of isolated spinach chloroplasts.

    PubMed Central

    Roughan, P G; Slack, C R; Holland, R

    1976-01-01

    Spinach chloroplasts, isolated by techniques yielding preparations with high O2- evolving activity, showed rates of light-dependent acetate incorporation into lipids 3-4 fold higher than any previously reported. Incorporation rates as high as 500 nmol of acetate/h per mg of chlorophyll were measured in buffered sorbitol solutions containing only NaHCO3 and [1-14C]acetate, and as high as 800 nmol/h per mg of chlorophyll when 0.13 mM-Triton X-100 was also included in the reaction media. The fatty acids synthesized were predominantly oleic (70-80% of the total fatty acid radioactivity) and palmitic (20-25%) with only minor amounts (1-5%) of linoleic acid. Linolenic acid synthesis was not detected in the system in vitro. Free fatty acids accounted for 70-90% of the radioactivity incorporated and the remainder was shared fairly evenly between 1,2-diacylglycerols and polar lipids. Oleic acid constituted 80-90% of the free fatty acids synthesized, but the diacylglycerols and polar lipids contained slightly more palmitic acid than oleic acid. Triton X-100 stimulated the synthesis of diacylglycerols 3-6 fold, but stimulated free fatty acid synthesis only 1-1.5-fold. Added glycerol 1-phosphate stimulated both the synthesis of diacylglycerols and palmitic acid relative to oleic acid, but did not increase acetate incorporation into total chloroplast lipids. CoA and ATP, when added separately, stimulated acetate incorporation into chloroplast lipids to variable extents and had no effect on the types of lipid synthesized, but when added together resulted in 34% of the incorporated acetate appearing in long-chain acyl-CoA. Pyruvate was a much less effective precursor of chloroplast fatty acids than was acetate. PMID:985452

  5. Multiple cytosolic calcium buffers in posterior pituitary nerve terminals.

    PubMed

    McMahon, Shane M; Chang, Che-Wei; Jackson, Meyer B

    2016-03-01

    Cytosolic Ca(2+) buffers bind to a large fraction of Ca(2+) as it enters a cell, shaping Ca(2+) signals both spatially and temporally. In this way, cytosolic Ca(2+) buffers regulate excitation-secretion coupling and short-term plasticity of release. The posterior pituitary is composed of peptidergic nerve terminals, which release oxytocin and vasopressin in response to Ca(2+) entry. Secretion of these hormones exhibits a complex dependence on the frequency and pattern of electrical activity, and the role of cytosolic Ca(2+) buffers in controlling pituitary Ca(2+) signaling is poorly understood. Here, cytosolic Ca(2+) buffers were studied with two-photon imaging in patch-clamped nerve terminals of the rat posterior pituitary. Fluorescence of the Ca(2+) indicator fluo-8 revealed stepwise increases in free Ca(2+) after a series of brief depolarizing pulses in rapid succession. These Ca(2+) increments grew larger as free Ca(2+) rose to saturate the cytosolic buffers and reduce the availability of Ca(2+) binding sites. These titration data revealed two endogenous buffers. All nerve terminals contained a buffer with a Kd of 1.5-4.7 µM, and approximately half contained an additional higher-affinity buffer with a Kd of 340 nM. Western blots identified calretinin and calbindin D28K in the posterior pituitary, and their in vitro binding properties correspond well with our fluorometric analysis. The high-affinity buffer washed out, but at a rate much slower than expected from diffusion; washout of the low-affinity buffer could not be detected. This work has revealed the functional impact of cytosolic Ca(2+) buffers in situ in nerve terminals at a new level of detail. The saturation of these cytosolic buffers will amplify Ca(2+) signals and may contribute to use-dependent facilitation of release. A difference in the buffer compositions of oxytocin and vasopressin nerve terminals could contribute to the differences in release plasticity of these two hormones.

  6. An insight into the role of phosphotransacetylase (pta) and the acetate/acetyl-CoA node in Escherichia coli

    PubMed Central

    Castaño-Cerezo, Sara; Pastor, José M; Renilla, Sergio; Bernal, Vicente; Iborra, José L; Cánovas, Manuel

    2009-01-01

    Background Acetate metabolism in Escherichia coli plays an important role in the control of the central metabolism and in bioprocess performance. The main problems related to the use of E. coli as cellular factory are i) the deficient utilization of carbon source due to the excretion of acetate during aerobic growth, ii) the inhibition of cellular growth and protein production by acetate and iii) the need for cofactor recycling (namely redox coenzymes and free CoASH) to sustain balanced growth and cellular homeostasis. Results This work analyzes the effect of mutations in the acetate excretion/assimilation pathways, acetyl-CoA synthethase (acs) and phosphotransacetylase (pta), in E. coli BW25113 grown on glucose or acetate minimal media. Biomass and metabolite production, redox (NADH/NAD+) and energy (ATP) state, enzyme activities and gene expression profiles related to the central metabolism were analyzed. The knock-out of pta led to a more altered phenotype than that of acs. Deletion of pta reduced the ability to grow on acetate as carbon source and strongly affected the expression of several genes related to central metabolic pathways. Conclusion Results showed that pta limits biomass yield in aerobic glucose cultures, due to acetate production (overflow metabolism) and its inefficient use during glucose starvation. Deletion of pta severely impaired growth on acetate minimal medium and under anaerobiosis due to decreased acetyl-coenzyme A synthethase, glyoxylate shunt and gluconeogenic activities, leading to lower growth rate. When acetate is used as carbon source, the joint expression of pta and acs is crucial for growth and substrate assimilation, while pta deletion severely impaired anaerobic growth. Finally, at an adaptive level, pta deficiency makes the strain more sensitive to environmental changes and de-regulates the central metabolism. PMID:19852855

  7. Trypanosomatidae produce acetate via a mitochondrial acetate:succinate CoA transferase.

    PubMed

    Van Hellemond, J J; Opperdoes, F R; Tielens, A G

    1998-03-17

    Hydrogenosome-containing anaerobic protists, such as the trichomonads, produce large amounts of acetate by an acetate:succinate CoA transferase (ASCT)/succinyl CoA synthetase cycle. The notion that mitochondria and hydrogenosomes may have originated from the same alpha-proteobacterial endosymbiont has led us to look for the presence of a similar metabolic pathway in trypanosomatids because these are the earliest-branching mitochondriate eukaryotes and because they also are known to produce acetate. The mechanism of acetate production in these organisms, however, has remained unknown. Four different members of the trypanosomatid family: promastigotes of Leishmania mexicana mexicana, L. infantum and Phytomonas sp., and procyclics of Trypanosoma brucei were analyzed as well as the parasitic helminth Fasciola hepatica. They all use a mitochondrial ASCT for the production of acetate from acetyl CoA. The succinyl CoA that is produced during acetate formation by ASCT is recycled presumably to succinate by a mitochondrial succinyl CoA synthetase, concomitantly producing ATP from ADP. The ASCT of L. mexicana mexicana promastigotes was further characterized after partial purification of the enzyme. It has a high affinity for acetyl CoA (Km 0.26 mM) and a low affinity for succinate (Km 6.9 mM), which shows that significant acetate production can occur only when high mitochondrial succinate concentrations prevail. This study identifies a metabolic pathway common to mitochondria and hydrogenosomes, which strongly supports a common origin for these two organelles.

  8. Synthesis of dipeptide precursors with an immobilized thermolysin in ethyl acetate.

    PubMed

    Nagayasu, T; Miyanaga, M; Tanaka, T; Sakiyama, T; Nakanishi, K

    1994-05-01

    N-(Benzyloxycarbonyl)-L-aspartyl-L-phenylalanine methyl ester (Z-AspPheOMe), a precursor of the aspartame, and N-(benzyloxycarbonyl)-L-phenylalanyl-Lphenylalanine methyl ester (Z-PhePheOMe) were synthesized from the respective amino acid derivatives with an immobilized thermolysin (EC 3.4.24.4) in ethyl acetate. Various factors affecting the synthesis of these dipeptide precursors were clarified. The initial synthetic rate was the highest at the water content of 3.5% for both reactions. The substrate concentration dependencies of the initial synthetic rate of Z-AspkPheOMe and Z-PhePheOMe with the immobilized enzyme in ethyl acetate were different from those in an aqueous buffer solution saturated with ethyl acetate but similar to those in the aqueous/organic biphasic system using the free enzyme. Particularly, the initial synthetic rate of Z-AspPhOMe increased in order higher than first order with respect to the concentration of L-phenylalanine methyl ester (PheOMe), whereas it decreased sharply with the concentration of N-(benzyloxycarbonyl)-L-aspartic acid (Z-Asp). Such kinetic behavior could be explained by regarding the inside of the immobilized enzyme as being a biphasic mode composed from the organic phase and aqueous phase where the enzymatic reaction takes place. The reaction in the aqueous/organic biphasic system using the free enzyme could be simulated by taking into consideration the partition of the substrate and the initial rate of synthesis in the aqueous buffer saturated with ethyl acetate. Based on this analysis, the rate of reaction with the immobilized enzyme in ethyl acetate could also be predicted. Z-AsPheOMe and Z-PhePheOMe were synthesized by the fed-batch method where the acid component of the substrate was intermittently added during the course of reaction and by the batch method. In the synthesis of Z-AspPheOMe, the synthetic rate and maximum yield of reaction as well as the stability of the immobilized enzyme were higher in the fed

  9. Acetate production from whey lactose using co-immobilized cells of homolactic and homoacetic bacteria in a fibrous-bed bioreactor

    SciTech Connect

    Huang, Y.; Yang, S.T.

    1998-11-20

    Acetate was produced from whey lactose in batch and fed-batch fermentations using co-immobilized cells of Clostridium formicoaceticum and Lactococcus lactis. The cells were immobilized in a spirally wound fibrous sheet packed in a 0.45-L column reactor, with liquid circulated through a 5-L stirred-tank fermentor. Industrial-grade nitrogen sources, including corn steep liquor, casein hydrolysate, and yeast hydrolysate, were studied as inexpensive nutrient supplements to whey permeate and acid whey. Supplementation with either 2.5% (v/v) corn steep liquor or 1.5 g/L casein hydrolysate was adequate for the cocultured fermentation. The overall acetic acid yield from lactose was 0.9 g/g, and the productivity was 0.25 g/(L h). Both lactate and acetate at high concentrations inhibited the homoacetic fermentation. To overcome these inhibitions, fed-batch fermentations were used to keep lactate concentration low and to adapt cells to high-concentration acetate. The final acetate concentration obtained in the fed-batch fermentations were used to keep lactate concentration low and to adapt cells to high-concentration acetate. The final acetate concentration obtained in the fed-batch fermentation was 75 g/L, which was the highest acetate concentration ever produced by C. formicoaceticum. Even at this high acetate concentration, the overall productivity was 0.18 g/(L h) based on the total medium volume and 1.23 g/(L h) based on the fibrous-bed reactor volume. The cells isolated from the fibrous-bed bioreactor at the end of this study were more tolerant to acetic acid than the original culture used to seed the bioreactor, indicating that adaptation and natural selection of acetate-tolerant strains occurred. This cocultured fermentation process could be used to produce a low-cost acetate deicer from whey permeate and acid whey.

  10. Contraction of rat thoracic aorta strips induced by phorbol 12-myristate 13-acetate

    SciTech Connect

    Itoh, H.; Lederis, K.

    1987-02-01

    Phorbol 12-myristate 13-acetate (PMA) induced a slow and progressive increase in tension of rat thoracic aorta strips in the presence of extracellular CaS . Complete relaxation could not be obtained in CaS -free buffer containing 1 mM ethyleneglycol-bis(US -aminoethylether)-N,N'-tetraacetic acid (EGTA) and 10 X M PMA. In the absence of extracellular CaS , PMA (10 X M) induced a small but sustained contraction which was not altered by the addition of another 2 mM EGTA and 3 x 10 V M verapamil. Papaverine (10 U M) relaxed the PMA-induced contraction to the base line, but phentolamine (10 V M), cyproheptadine (10 V M), atropine (10 V M) and tetrodotoxine (10 W M) did not change the contraction. CaS -depleted muscle strips, prepared by four repeated applications of 10 X M norepinephrine in CaS -free buffer, were contracted by 10 X M PMA, but at a lower maximum tension than nontreated strips. The action of PMA on rat aorta strips in CaS -free buffer did not require the presence of the adventitial layer or endothelial cells. These results suggest that PMA may induce activation of protein kinase C and smooth muscle contraction in the absence of extracellular CaS , without an increase in myoplasmic CaS .

  11. Microscopic optical buffering in a harmonic potential

    PubMed Central

    Sumetsky, M.

    2015-01-01

    In the early days of quantum mechanics, Schrödinger noticed that oscillations of a wave packet in a one-dimensional harmonic potential well are periodic and, in contrast to those in anharmonic potential wells, do not experience distortion over time. This original idea did not find applications up to now since an exact one-dimensional harmonic resonator does not exist in nature and has not been created artificially. However, an optical pulse propagating in a bottle microresonator (a dielectric cylinder with a nanoscale-high bump of the effective radius) can exactly imitate a quantum wave packet in the harmonic potential. Here, we propose a tuneable microresonator that can trap an optical pulse completely, hold it as long as the material losses permit, and release it without distortion. This result suggests the solution of the long standing problem of creating a microscopic optical buffer, the key element of the future optical signal processing devices. PMID:26689546

  12. Common data buffer system. [communication with computational equipment utilized in spacecraft operations

    NASA Technical Reports Server (NTRS)

    Byrne, F. (Inventor)

    1981-01-01

    A high speed common data buffer system is described for providing an interface and communications medium between a plurality of computers utilized in a distributed computer complex forming part of a checkout, command and control system for space vehicles and associated ground support equipment. The system includes the capability for temporarily storing data to be transferred between computers, for transferring a plurality of interrupts between computers, for monitoring and recording these transfers, and for correcting errors incurred in these transfers. Validity checks are made on each transfer and appropriate error notification is given to the computer associated with that transfer.

  13. Active Oxygen Metabolites and Thromboxane in Phorbol Myristate Acetate Toxicity to the Isolated, Perfused Rat Lung.

    NASA Astrophysics Data System (ADS)

    Carpenter, Laurie Jean

    When administered intravenously or intratracheally to rats, rabbits and sheep, phorbol myristate acetate (PMA) produces changes in lung morphology and function are similar to those seen in humans with the adult respiratory distress syndrome (ARDS). Therefore, it is thought that information about the mechanism of ARDS development can be gained from experiments using PMA-treated animals. Currently, the mechanisms by which PMA causes pneumotoxicity are unknown. Results from other studies in rabbits and in isolated, perfused rabbit lungs suggest that PMA-induced lung injury is mediated by active oxygen species from neutrophils (PMN), whereas studies in sheep and rats suggest that PMN are not required for the toxic response. The role of PMN, active oxygen metabolites and thromboxane (TxA_2) in PMA-induced injury to isolated, perfused rat lungs (IPLs) was examined in this thesis. To determine whether PMN were required for PMA to produce toxicity to the IPL, lungs were perfused for 30 min with buffer containing various concentrations of PMA (in the presence or absence of PMN). When concentrations >=q57 ng/ml were added to medium devoid of added PMN, perfusion pressure and lung weight increased. When a concentration of PMA (14-28 ng/ml) that did not by itself cause lungs to accumulate fluid was added to the perfusion medium containing PMN (1 x 10 ^8), perfusion pressure increased, and lungs accumulated fluid. These results indicate that high concentrations of PMA produce lung injury which is independent of PMN, whereas injury induced by lower concentrations is PMN-dependent. To examine whether active oxygen species were involved in mediating lung injury induced by PMA and PMN, lungs were coperfused with the oxygen radical scavengers SOD and/or catalase. Coperfusion with either or both of these enzymes totally protected lungs against injury caused by PMN and PMA. These results suggest that active oxygen species (the hydroxyl radical in particular), mediate lung injury in

  14. Cost of riparian buffer zones: A comparison of hydrologically adapted site-specific riparian buffers with traditional fixed widths

    NASA Astrophysics Data System (ADS)

    Tiwari, T.; Lundström, J.; Kuglerová, L.; Laudon, H.; Öhman, K.; Ågren, A. M.

    2016-02-01

    Traditional approaches aiming at protecting surface waters from the negative impacts of forestry often focus on retaining fixed width buffer zones around waterways. While this method is relatively simple to design and implement, it has been criticized for ignoring the spatial heterogeneity of biogeochemical processes and biodiversity in the riparian zone. Alternatively, a variable width buffer zone adapted to site-specific hydrological conditions has been suggested to improve the protection of biogeochemical and ecological functions of the riparian zone. However, little is known about the monetary value of maintaining hydrologically adapted buffer zones compared to the traditionally used fixed width ones. In this study, we created a hydrologically adapted buffer zone by identifying wet areas and groundwater discharge hotspots in the riparian zone. The opportunity cost of the hydrologically adapted riparian buffer zones was then compared to that of the fixed width zones in a meso-scale boreal catchment to determine the most economical option of designing riparian buffers. The results show that hydrologically adapted buffer zones were cheaper per hectare than the fixed width ones when comparing the total cost. This was because the hydrologically adapted buffers included more wetlands and low productive forest areas than the fixed widths. As such, the hydrologically adapted buffer zones allows more effective protection of the parts of the riparian zones that are ecologically and biogeochemically important and more sensitive to disturbances without forest landowners incurring any additional cost than fixed width buffers.

  15. The Multimission Image Processing Laboratory's virtual frame buffer interface

    NASA Technical Reports Server (NTRS)

    Wolfe, T.

    1984-01-01

    Large image processing systems use multiple frame buffers with differing architectures and vendor supplied interfaces. This variety of architectures and interfaces creates software development, maintenance and portability problems for application programs. Several machine-dependent graphics standards such as ANSI Core and GKS are available, but none of them are adequate for image processing. Therefore, the Multimission Image Processing laboratory project has implemented a programmer level virtual frame buffer interface. This interface makes all frame buffers appear as a generic frame buffer with a specified set of characteristics. This document defines the virtual frame uffer interface and provides information such as FORTRAN subroutine definitions, frame buffer characteristics, sample programs, etc. It is intended to be used by application programmers and system programmers who are adding new frame buffers to a system.

  16. Process for the preparation of vinyl acetate

    DOEpatents

    Tustin, G.C.; Zoeller, J.R.; Depew, L.S.

    1998-02-17

    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 and 200 C and removing the reaction products from the contact zone.

  17. Process for the preparation of vinyl acetate

    DOEpatents

    Tustin, Gerald Charles; Zoeller, Joseph Robert; Depew, Leslie Sharon

    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.

  18. 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.

  19. Fragrance material review on phenethyl acetate.

    PubMed

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

    2012-09-01

    A toxicologic and dermatologic review of phenethyl acetate when used as a fragrance ingredient is presented. Phenethyl 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 phenethyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, toxicokinetics, repeated dose, genotoxicity, and carcinogenicity 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.

  20. 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.

  1. Advanced Colloids Experiment (ACE-T1)

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Sicker, Ron; Brown, Dan; Eustace, John

    2015-01-01

    Increment 45 - 46 Science Symposium presentation of Advanced Colloids Experiment (ACE-T1) to RPO. The purpose of this event is for Principal Investigators to present their science objectives, testing approach, and measurement methods to agency scientists, managers, and other investigators.

  2. Corrosion of stainless steel during acetate production

    SciTech Connect

    Qi, J.S.; Lester, G.C.

    1996-07-01

    Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CH{sub 3}COOH under the process conditions commonly practiced in industry. The corrosive action of the catalyst occurred only in the presence of water. Thus, for the batch processes, corrosion occurred mostly during the initial stage of esterification, where water produced by the reaction created an aqueous environment. After water was distilled off, the corrosion rate declined to a negligible value. The corrosion inhibitor copper sulfate, often used in industrial acetate processes, was found to work well for a low-temperature process (< 95 C) such as in production of butyl acetate, but it accelerated corrosion in the glycol ether acetate processes where temperatures were > 108 C. Process conditions that imparted low corrosion rates were determined.

  3. Cellulose Acetate Membranes: Electron Microscopy of Structure.

    PubMed

    Riley, R; Gardner, J O; Merten, U

    1964-02-21

    Electron photomicrographs of cellulose acetate membranes used in the reverse osmosis processof water desalination reveal a dense surface layer with a porous substructure. The high rate oftransmission for water can be correlated with the thickness of the dense layer on the air-driedsurface of the membrane.

  4. Synthesis of Cellulose Acetate from Cotton Byproducts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton burr and cottonseed hull are relatively inexpensive cotton byproducts. In an effort to derive greater value out of these natural renewable materials, we have succeeded in converting part of them into cellulose acetate without prior chemical breakdown or physical separation of cellulose, ligni...

  5. The role of activated acetate intermediates in the control of Escherichia coli biofilm amounts

    PubMed Central

    Mugabi, Robert; Sandgren, Daniel; Born, Megan; Leith, Ian; Horne, Shelley M.; Prüβ, Birgit M.

    2013-01-01

    A previous study postulated that acetate metabolism was a metabolic sensory mechanism that related information about E. coli’s environment to the formation of biofilms (Prüβ et al., Arch. Microbiol. 2010). Considering that mutants in pta ackA (no acetyl phosphate) and ackA (high acetyl phosphate) exhibited similarly increased biofilm amounts and three dimensional structures, the hypothesis for this study was that acetyl Co-A was a more likely mediator of the acetate effect than acetyl phosphate. The effect of acetate metabolism on biofilm amounts was detailed by using single carbon sources rather than the previously used mixed amino acid medium, as well as mutations in additional genes that contribute to acetate metabolism (ldhA, pflA, pflB). In summary, the mutations in ackA, pta ackA, and ldhA increased biofilm amounts in the presence of maltose, D-trehalose, D-mannose, and L-rhamnose, all of which get converted to acetyl-CoA. The ackA mutant also exhibited increased biofilm amounts in the presence of inosine and thymidine. The mutation in pflA decreased biofilm amounts in the presence of maltotriose, uridine, D-serine, and acetate. Since ackA, pta ackA, and ldhA mutants are expected to exhibit increased intracellular acetyl-CoA levels, and pflA and pflB mutants likely exhibit decreased acetyl-CoA concentrations, we believe that acetyl-CoA is the activated acetate intermediate that controls biofilm amounts. PMID:24324879

  6. Acetal phosphatidic acids: novel platelet aggregating agents.

    PubMed

    Brammer, J P; Maguire, M H; Walaszek, E J; Wiley, R A

    1983-05-01

    1 Palmitaldehyde, olealdehyde and linolealdehyde acetal phosphatidic acids induced rapid shape change and dose-dependent biphasic aggregation of human platelets in platelet-rich plasma; aggregation was reversible at low doses and irreversible at high doses of the acetal phosphatidic acids. The palmitaldehyde congener elicited monophasic dose-dependent aggregation of sheep platelets in platelet-rich plasma.2 The threshold concentration for palmitaldehyde acetal phosphatidic acid (PGAP)-induced platelet aggregation was 2.5-5 muM for human platelets and 0.25-0.5 muM for sheep platelets. PGAP was 4-5 times as potent versus human platelets as the olealdehyde and linolealdehyde acetal phosphatidic acids, which were equipotent.3 PGAP-induced irreversible aggregation of [(14)C]-5-hydroxytryptamine ([(14)C]-5-HT)-labelled human platelets in platelet-rich plasma was accompanied by release of 44.0+/-2.4% (s.e.) of the platelet [(14)C]-5-HT; reversible aggregation was not associated with release. In contrast, PGAP-induced release of [(14)C]-5-HT-labelled sheep platelets was dose-dependent.4 The adenosine diphosphate (ADP) antagonist, 2-methylthio-AMP, and the cyclo-oxygenase inhibitor, aspirin, abolished PGAP-induced second phase aggregation and release in human platelets but did not affect the first, reversible, phase of aggregation. Both the first and second phases of PGAP-induced aggregation were abolished by chlorpromazine, by the phospholipase A(2) inhibitor, mepacrine, and by nmolar concentrations of prostaglandin E(1) (PGE(1)); these agents abolished the second, but not the first phase of ADP-induced aggregation.5 The related phospholipids, lecithin, lysolecithin and phosphatidic acid, at <100 muM, neither induced aggregation of human platelets in platelet-rich plasma, nor modified PGAP-induced aggregation; 1-palmityl lysophosphatidic acid elicited aggregation of human platelets at a threshold concentration of 100 muM.6 It is concluded that the acetal phosphatidic acids

  7. Grass buffers for playas in agricultural landscapes: A literature synthesis

    USGS Publications Warehouse

    Melcher, Cynthia P.; Skagen, Susan K.

    2005-01-01

    Future research should entail multiple-scale approaches at regional, wetland-complex, and individual watershed scales. Information needs include direct measures of buffer effectiveness in ‘real-world’ systems, refinement and field tests of buffer-effectiveness models, how buffers may affect floral and faunal communities of playas, and basic ecological information on playa function and playa wildlife ecology. Understanding how wildlife communities respond to patch size and habitat fragmentation is crucial for addressing questions regarding habitat quality of grass buffers in playa systems.

  8. 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.

  9. Buffers affect the bending rigidity of model lipid membranes.

    PubMed

    Bouvrais, Hélène; Duelund, Lars; Ipsen, John H

    2014-01-14

    In biophysical and biochemical studies of lipid bilayers the influence of the used buffer is often ignored or assumed to be negligible on membrane structure, elasticity, or physical properties. However, we here present experimental evidence, through bending rigidity measurements performed on giant vesicles, of a more complex behavior, where the buffering molecules may considerably affect the bending rigidity of phosphatidylcholine bilayers. Furthermore, a synergistic effect on the bending modulus is observed in the presence of both salt and buffer molecules, which serves as a warning to experimentalists in the data interpretation of their studies, since typical lipid bilayer studies contain buffer and ion molecules.

  10. Solubilization of proteins: the importance of lysis buffer choice.

    PubMed

    Peach, Mandy; Marsh, Noelle; Miskiewicz, Ewa I; MacPhee, Daniel J

    2015-01-01

    The efficient extraction of proteins of interest from cells and tissues is not always straightforward. Here we demonstrate the differences in extraction of the focal adhesion protein Kindlin-2 from choriocarcinoma cells using NP-40 and RIPA lysis buffer. Furthermore, we demonstrate the use of a more denaturing urea/thiourea lysis buffer for solubilization, by comparing its effectiveness for solubilization of small heat-shock proteins from smooth muscle with the often utilized RIPA lysis buffer. Overall, the results demonstrate the importance of establishing the optimal lysis buffer for specific protein solubilization within the experimental workflow.

  11. An assessment of buffer strips for improving damage tolerance

    NASA Technical Reports Server (NTRS)

    Poe, C. C., Jr.; Kennedy, J. M.

    1981-01-01

    Graphite/epoxy panels with buffer strips were tested in tension to measure their residual strength with crack-like damage. Panels were made with 45/0/-45/90(2S) and 45/0/450(2S) layups. The buffer strips were parallel to the loading directions. They were made by replacing narrow strips of the 0 deg graphite plies with strips of either 0 deg S-Glass/epoxy or Kevlar-49/epoxy on either a one for one or a two for one basis. In a third case, O deg graphite/epoxy was used as the buffer material and thin, perforated Mylar strips were placed between the 0 deg piles and the cross-plies to weaken the interfaces and thus to isolate the 0 deg plies. Some panels were made with buffer strips of different widths and spacings. The buffer strips arrested the cracks and increased the residual strengths significantly over those plain laminates without buffer strips. A shear-lag type stress analysis correctly predicted the effects of layups, buffer material, buffer strip width and spacing, and the number of plies of buffer material.

  12. Back contact buffer layer for thin-film solar cells

    DOEpatents

    Compaan, Alvin D.; Plotnikov, Victor V.

    2014-09-09

    A photovoltaic cell structure is disclosed that includes a buffer/passivation layer at a CdTe/Back contact interface. The buffer/passivation layer is formed from the same material that forms the n-type semiconductor active layer. In one embodiment, the buffer layer and the n-type semiconductor active layer are formed from cadmium sulfide (CdS). A method of forming a photovoltaic cell includes the step of forming the semiconductor active layers and the buffer/passivation layer within the same deposition chamber and using the same material source.

  13. MES Buffer Affects Arabidopsis Root Apex Zonation and Root Growth by Suppressing Superoxide Generation in Root Apex.

    PubMed

    Kagenishi, Tomoko; Yokawa, Ken; Baluška, František

    2016-01-01

    In plants, growth of roots and root hairs is regulated by the fine cellular control of pH and reactive oxygen species (ROS). MES, 2-(N-morpholino)ethanesulfonic acid as one of the Good's buffers has broadly been used for buffering medium, and it is thought to suit for plant growth with the concentration at 0.1% (w/v) because the buffer capacity of MES ranging pH 5.5-7.0 (for Arabidopsis, pH 5.8). However, many reports have shown that, in nature, roots require different pH values on the surface of specific root apex zones, namely meristem, transition zone, and elongation zone. Despite the fact that roots always grow on a media containing buffer molecule, little is known about impact of MES on root growth. Here, we have checked the effects of different concentrations of MES buffer using growing roots of Arabidopsis thaliana. Our results show that 1% of MES significantly inhibited root growth, the number of root hairs and length of meristem, whereas 0.1% promoted root growth and root apex area (region spanning from the root tip up to the transition zone). Furthermore, superoxide generation in root apex disappeared at 1% of MES. These results suggest that MES disturbs normal root morphogenesis by changing the ROS homeostasis in root apex. PMID:26925066

  14. MES Buffer Affects Arabidopsis Root Apex Zonation and Root Growth by Suppressing Superoxide Generation in Root Apex

    PubMed Central

    Kagenishi, Tomoko; Yokawa, Ken; Baluška, František

    2016-01-01

    In plants, growth of roots and root hairs is regulated by the fine cellular control of pH and reactive oxygen species (ROS). MES, 2-(N-morpholino)ethanesulfonic acid as one of the Good’s buffers has broadly been used for buffering medium, and it is thought to suit for plant growth with the concentration at 0.1% (w/v) because the buffer capacity of MES ranging pH 5.5–7.0 (for Arabidopsis, pH 5.8). However, many reports have shown that, in nature, roots require different pH values on the surface of specific root apex zones, namely meristem, transition zone, and elongation zone. Despite the fact that roots always grow on a media containing buffer molecule, little is known about impact of MES on root growth. Here, we have checked the effects of different concentrations of MES buffer using growing roots of Arabidopsis thaliana. Our results show that 1% of MES significantly inhibited root growth, the number of root hairs and length of meristem, whereas 0.1% promoted root growth and root apex area (region spanning from the root tip up to the transition zone). Furthermore, superoxide generation in root apex disappeared at 1% of MES. These results suggest that MES disturbs normal root morphogenesis by changing the ROS homeostasis in root apex. PMID:26925066

  15. Quantifying the sensitivity of G. oxydans ATCC 621H and DSM 3504 to osmotic stress triggered by soluble buffers.

    PubMed

    Luchterhand, B; Fischöder, T; Grimm, A R; Wewetzer, S; Wunderlich, M; Schlepütz, T; Büchs, J

    2015-04-01

    In Gluconobacter oxydans cultivations on glucose, CaCO3 is typically used as pH-buffer. This buffer, however, has disadvantages: suspended CaCO3 particles make the medium turbid, thereby, obstructing analysis of microbial growth via optical density and scattered light. Upon searching for alternative soluble pH-buffers, bacterial growth and productivity was inhibited most probably due to osmotic stress. Thus, this study investigates in detail the osmotic sensitivity of G. oxydans ATCC 621H and DSM 3504 using the Respiratory Activity MOnitoring System. The tested soluble pH-buffers and other salts attained osmolalities of 0.32-1.19 osmol kg(-1). This study shows that G. oxydans ATCC 621H and DSM 3504 respond quite sensitively to increased osmolality in comparison to other microbial strains of industrial interest. Osmolality values of >0.5 osmol kg(-1) should not be exceeded to avoid inhibition of growth and product formation. This osmolality threshold needs to be considered when working with soluble pH-buffers.

  16. Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions.

    PubMed

    Casella, S; Piccione, D; Ielati, S; Bocchino, E G; Piccione, G

    2013-06-01

    The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome-citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incubated with two different experimental buffer solutions (buffer A: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM glucose; and buffer B: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM MgCl2) in a water bath for 1 h at 25 °C and 37 °C. Normal erythrocytes, suspended at 3% hematocrit, were used to measure the SO4= influx by absorption spectrophotometry at 425 nm wavelength. Unpaired Student's t-test showed a statistically significant decrease (P < 0.01) of rate constants in equine erythrocytes at 25 °C versus 37 °C using both experimental buffer solutions. Comparing the buffer A with buffer B unpaired Student's t-test showed statistically lower values (P < 0.0001) for A solution versus B solution both at 25 °C and at 37 °C. The greater inhibition of SO4 (=) influx measured in equine erythrocytes indicates the increased formation of the sulfydryl bonds in band 3 and the modulation of the sulfydryl groups, culminating in the conformational changes in band 3.

  17. Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions.

    PubMed

    Casella, S; Piccione, D; Ielati, S; Bocchino, E G; Piccione, G

    2013-06-01

    The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome-citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incubated with two different experimental buffer solutions (buffer A: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM glucose; and buffer B: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM MgCl2) in a water bath for 1 h at 25 °C and 37 °C. Normal erythrocytes, suspended at 3% hematocrit, were used to measure the SO4= influx by absorption spectrophotometry at 425 nm wavelength. Unpaired Student's t-test showed a statistically significant decrease (P < 0.01) of rate constants in equine erythrocytes at 25 °C versus 37 °C using both experimental buffer solutions. Comparing the buffer A with buffer B unpaired Student's t-test showed statistically lower values (P < 0.0001) for A solution versus B solution both at 25 °C and at 37 °C. The greater inhibition of SO4 (=) influx measured in equine erythrocytes indicates the increased formation of the sulfydryl bonds in band 3 and the modulation of the sulfydryl groups, culminating in the conformational changes in band 3. PMID:23015199

  18. What's in your buffer? Solute altered millisecond motions detected by solution NMR.

    PubMed

    Wong, Madeline; Khirich, Gennady; Loria, J Patrick

    2013-09-17

    To date, little work has been conducted on the relationship between solute and buffer molecules and conformational exchange motion in enzymes. This study uses solution NMR to examine the effects of phosphate, sulfate, and acetate in comparison to MES- and HEPES-buffered references on the chemical shift perturbation and millisecond, chemical, or conformational exchange motions in the enzyme ribonuclease A (RNase A), triosephosphate isomerase (TIM) and HisF. The results indicate that addition of these solutes has a small effect on (1)H and (15)N chemical shifts for RNase A and TIM but a significant effect for HisF. For RNase A and TIM, Carr-Purcell-Meiboom-Gill relaxation dispersion experiments, however, show significant solute-dependent changes in conformational exchange motions. Some residues show loss of millisecond motions relative to the reference sample upon addition of solute, whereas others experience an enhancement. Comparison of exchange parameters obtained from fits of dispersion data indicates changes in either or both equilibrium populations and chemical shifts between conformations. Furthermore, the exchange kinetics are altered in many cases. The results demonstrate that common solute molecules can alter observed enzyme millisecond motions and play a more active role than what is routinely believed.

  19. Influence of amino acids, buffers, and ph on the γ-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 γ-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

  20. 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)

  1. The microwave spectrum of n-hexyl acetate and structural aspects of n-alkyl acetates

    NASA Astrophysics Data System (ADS)

    Attig, T.; Kannengießer, R.; Kleiner, I.; Stahl, W.

    2014-04-01

    The microwave spectrum of n-hexyl acetate was recorded in the range of 10-13.5 GHz using the Aachen MB-FTMW spectrometer. The rotational constants of the most abundant conformer were determined to be A = 3.3591100(32) GHz, B = 0.39596553(53) GHz, and C = 0.36999804(31) GHz. Quantum chemical calculations for specific conformers were carried out at the MP2/6-311++G(d,p) level. The programs XIAM and BELGI were used to analyze the internal rotation of the acetyl methyl group. The observed conformer of n-hexyl acetate was compared to the lowest energy conformers of n-butyl acetate and n-pentyl acetate.

  2. Isolation of an enzyme complex with carbon monoxide dehydrogenase activity containing corrinoid and nickel from acetate-grown Methanosarcina thermophila.

    PubMed Central

    Terlesky, K C; Nelson, M J; Ferry, J G

    1986-01-01

    Fast protein liquid chromatography of cell extract from methanol- or acetate-grown Methanosarcina thermophila resolved two peaks of CO dehydrogenase activity. The activity of one of the CO dehydrogenases was sixfold greater in acetate-grown compared with methanol-grown cells. This CO dehydrogenase was purified to apparent homogeneity (70 mumol of methyl viologen reduced per min per mg of protein) and made up greater than 10% of the cellular protein of acetate-grown cells. The native enzyme (Mr 250,000) formed aggregates with an Mr of approximately 1,000,000. The enzyme contained five subunits (Mrs 89,000, 71,000, 60,000, 58,000, and 19,000), suggesting a multifunctional enzyme complex. Nickel, iron, cobalt, zinc, inorganic sulfide, and a corrinoid were present in the complex. The UV-visible spectrum suggested the presence of iron-sulfur centers. The electron paramagnetic resonance spectrum contained g values of 2.073, 2.049, and 2.028; these features were broadened in enzyme that was purified from cells grown in the presence of medium enriched with 61Ni, indicating the involvement of this metal in the spectrum. The pattern of potassium cyanide inhibition indicated that cyanide binds at or near the CO binding site. The properties of the enzyme imply an involvement in the dissimilation of acetate to methane, possibly by cleavage of acetate or activated acetate. Images PMID:3023296

  3. Stereoselective synthesis of the dimethyl acetals of. beta. ,. gamma. -unsaturated aldehydes from alkyl trans-2-methoxypropyl ketones

    SciTech Connect

    Kulinkovich, O.G.; Tishchenko, I.G.; Sorokin, V.L.

    1986-01-10

    trans-(2-Methoxycyclopropyl)carbinols were obtained in the form of equimolar mixtures of diastereomers by the reaction of the respective alkyl trans-2-methoxy-cyclopropyl ketones with lithium aluminum hydride or organometallic compounds. Methanolysis of the products in an acidic medium leads to high yields of the dimethyl acetals of trans- and cis-..beta..,..gamma..-unsaturated aldehydes, in which the content of the trans isomer amounts to 55-70%. The dimethyl acetals of trans-..beta..-..gamma..-unsaturated aldehydes can be produced by this method with greater stereoselectivity by reduction in the degree of transformation of the initial carbinols.

  4. COS Side 2 Science Data Buffer Check/Self-Tests for CS Buffer RAM and DIB RAM

    NASA Astrophysics Data System (ADS)

    Bacinski, John

    2013-10-01

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

  5. Ca(2+) Binding and Transport Studied with Ca(2+)/EGTA Buffers and (45)Ca(2+).

    PubMed

    Sehgal, Pankaj; Olesen, Claus; Møller, Jesper V

    2016-01-01

    The chapter describes procedures useful for determination of Ca(2+) binding by membranous Ca(2+)-ATPase based on the correction for the removal of Ca(2+) present in a non-bound state in the suspension medium. This is done by a filtration procedure that retains the membranous material on the Millipore filters. With suitable sucking devices it is possible to gently remove without dehydration nearly all medium from the Ca(2+) containing membranes, except that required for wetting of the filters on which they are deposited. Correction for this effect can be done with a double-filter where the radioactive content of the lower (protein-free) filter is subtracted from that present in the upper filter for calculation of Ca(2+) binding. This methodology can be used to study the effect of inhibitors on Ca(2+) binding and -transport, and with Ca(2+)/EGTA buffers to explore the Ca(2+) binding affinities and cooperative aspects of the two transport sites.

  6. Oral delivery of octreotide acetate in Intravail® improves uptake, half-life, and bioavailability over subcutaneous administration in male Swiss webster mice.

    PubMed

    Maggio, Edward T; Grasso, Patricia

    2011-04-11

    The most effective option for the medical treatment of patients with acromegaly is the use of somatostatin analogs. Octreotide acetate is a synthetic analog of somatostatin, with similar effects but a prolonged duration of action. Octreotide acetate is routinely given by subcutaneous (s.c.) or intramuscular injection. In the present study, we examined the feasibility of oral delivery of octreotide acetate reconstituted with increasing concentrations (0.5%, 1.5% and 3.0%) of Intravail®, a patented alkylsaccharide transmucosal absorption enhancing agent. The pharmacokinetics of orally delivered (by gavage) octreotide acetate in Intravail® were compared to those of octreotide acetate administered subcutaneously in sodium acetate buffer to male Swiss Webster mice. Oral delivery of octreotide acetate in 0.5% Intravail® significantly enhanced total uptake (1254.08ng/ml/min vs. 311.63ng/ml/min, respectively), serum half-life (52.1min vs. 1.3min, respectively), and relative bioavailability (4.0 vs. 1.0, respectively) when compared to delivery by s.c. injection. Higher concentrations of Intravail ®did not further enhance uptake, serum half-life, or bioavailability. The results of this study indicate that oral delivery of octreotide acetate in Intravail®is feasible, and is an effective method of administration which significantly improves uptake, bioavailability and half-life when compared to s.c. injection. Thus, oral delivery of octreotide acetate in Intravail® may have significant potential as a novel, non-invasive approach to the treatment of acromegaly and octreotide-mediated symptoms of carcinoid and VIP-secreting tumors.

  7. [The use of antioxidants (alpha-tocopherol acetate) in the treatment of diabetes mellitus].

    PubMed

    Kuznetsov, N S; Abulela, A M; Neskoromnyĭ, V N

    1993-01-01

    The authors have examined the time course of lipid peroxidation processes and the levels of total lipids in red cell membranes and blood plasma of diabetics administered alpha-tocopherol acetate. Patients with medium-severe diabetes of the first and second types were divided into 2 groups. Group 1 patients were administered only traditional sugar-reducing treatment, in Group 2 alpha-tocopherol acetate in a daily dose 300 mg was added to such therapy. Similar examinations were carried out in both the groups before and after the treatment. Lipid peroxidation levels and the content of total lipids were found significantly increased in the cellular membranes and blood plasma of Group 2 patients, whereas in Group 1 no changes of this kind were detected. Therapy with alpha-tocopherol acetate normalized lipid peroxidation processes in the red cell membranes and the total lipid content in the blood plasma, reduced the blood plasma level of lipid peroxidation products and the content of total lipids in red cell membranes. These results permit a conclusion on the favorable effect of alpha-tocopherol acetate on blood plasma lipid peroxidation and total lipid levels in diabetics.

  8. Ethanol and acetate production by Clostridium ljungdahlii and Clostridium autoethanogenum using resting cells.

    PubMed

    Cotter, Jacqueline L; Chinn, Mari S; Grunden, Amy M

    2009-04-01

    Combined gasification and fermentation technologies can potentially produce biofuels from renewable biomass. Gasification generates synthesis gas consisting primarily of CO, CO(2), H(2), N(2), with smaller amounts of CH(4), NO(x), O(2), C(2) compounds, ash and tars. Several anaerobic bacteria species can ferment bottled mixtures of pure synthesis gas constituents. However, there are challenges to maintaining culture viability of synthesis gas exposed cells. This study was designed to enhance culture stability and improve ethanol-to-acetate ratios using resting (non-growing) cells in synthesis gas fermentation. Resting cell states were induced in autotrophic Clostridium ljungdahlii cultures with minimal ethanol and acetate production due to low metabolic activity compared to growing cell production levels of 5.2 and 40.1 mM of ethanol and acetate. Clostridium autoethanogenum cultures were not induced into true resting states but did show improvement in total ethanol production (from 5.1 mM in growing cultures to 9.4 in one nitrogen-limited medium) as well as increased shifts in ethanol-to-acetate production ratios.

  9. Strong mutator phenotype drives faster adaptation from growth on glucose to growth on acetate in Salmonella.

    PubMed

    Le Bars, Hervé; Bonnaure-Mallet, Martine; Barloy-Hubler, Frédérique; Jolivet-Gougeon, Anne; Bousarghin, Latifa

    2014-10-01

    The metabolic adaptation of strong mutator strains was studied to better understand the link between the strong mutator phenotype and virulence. Analysis of the growth curves of isogenic strains of Salmonella, which were previously grown in M63 glucose media, revealed that the exponential phase of growth was reached earlier in an M63 acetate medium with strong mutator strains (mutated in mutS or in mutL) than with normomutator strains (P<0.05). Complemented strains confirmed the direct role of the strong mutator phenotype in this faster metabolic adaptation to the assimilation of acetate. In a mixed cell population, proliferation of strong mutators over normomutators was observed when the carbon source was switched from glucose to acetate. These results add to the sparse body of knowledge about strong mutators and highlight the selective advantage conferred by the strong mutator phenotype to adapt to a switch of carbon source in the environment. This work may provide clinically useful information given that there is a high prevalence of strong mutators among pathogenic strains of Salmonella and that acetate is the principal short chain fatty acid of the human terminal ileum and colon where Salmonella infection is localized.

  10. Evaluation of the potential carcinogenicity of cadmium, cadium acetate, cadmium bromide, cadmium chloride. Final report

    SciTech Connect

    Not Available

    1988-06-01

    Cadmium is a probable human carcinogen, classified as weight-of-evidence Group B1 under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). Evidence on potential carcinogenicity from animal studies is Sufficient, and the evidence from human studies is Limited. The potency factor (F) for cadmium is estimated to be 57.9/(mg/kg/day) (based on epidemiology data for cadmium workers), placing it in potency group 2 according to the CAG's methodology for evaluating potential carcinogens (U.S. EPA, 1986b). Cadmium weight of evidence and potency are based on epidemiology data for cadmium workers exposed to cadmium oxide and/or cadmium fume. Although human data for cadmium salts are lacking, due to the responsiveness of animals to soluble cadmium compounds, especially cadmium chloride, the weight of evidence and potency for cadmium acetate, cadmium bromide and cadmium chloride are considered to be the same as those cadmium compounds to which workers are exposed. Thus, cadmium acetate, cadmium bromide, and cadmium chloride are all classified as weight-of-evidence Group and the potency group, cadmium, cadmium acetate, cadmium bromide, and cadmium chloride are assigned MEDIUM hazard rankings for the purposes of RQ adjustment. Combining the weight-of-evidence group and the potency group, carbon tetrachloride is assigned a MEDIUM hazard ranking for the purposes of RQ adjustment.

  11. Ligand-enhanced electrokinetic remediation of metal-contaminated marine sediments with high acid buffering capacity.

    PubMed

    Masi, Matteo; Iannelli, Renato; Losito, Gabriella

    2016-06-01

    The suitability of electrokinetic remediation for removing heavy metals from dredged marine sediments with high acid buffering capacity was investigated. Laboratory-scale electrokinetic remediation experiments were carried out by applying two different voltage gradients to the sediment (0.5 and 0.8 V/cm) while circulating water or two different chelating agents at the electrode compartments. Tap water, 0.1 M citric acid and 0.1 M ethylenediaminetetraacetic acid (EDTA) solutions were used respectively. The investigated metals were Zn, Pb, V, Ni and Cu. In the unenhanced experiment, the acid front could not propagate due to the high acid buffering capacity of the sediments; the production of OH(-) ions at the cathode resulted in a high-pH environment causing the precipitation of CaCO3 and metal hydroxides. The use of citric acid prevented the formation of precipitates, but solubilisation and mobilisation of metal species were not sufficiently achieved. Metal removal was relevant when EDTA was used as the conditioning agent, and the electric potential was raised up to 0.8 V/cm. EDTA led to the formation of negatively charged complexes with metals which migrated towards the anode compartment by electromigration. This result shows that metal removal from sediments with high acid buffering capacity may be achieved by enhancing the electrokinetic process by EDTA addition when the acidification of the medium is not economically and/or environmentally sustainable. PMID:26490900

  12. 21 CFR 582.5892 - a-Tocopherol acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5892 a-Tocopherol acetate. (a) Product. a-Tocopherol acetate. (b) Conditions of use....

  13. 21 CFR 582.5892 - a-Tocopherol acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5892 a-Tocopherol acetate. (a) Product. a-Tocopherol acetate. (b) Conditions of use....

  14. 21 CFR 582.5892 - a-Tocopherol acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5892 a-Tocopherol acetate. (a) Product. a-Tocopherol acetate. (b) Conditions of use....

  15. Hypermedia as medium

    NASA Technical Reports Server (NTRS)

    Dede, Christopher J.

    1990-01-01

    Claims and rebuttals that hypermedia (the associative, nonlinear interconnection of multimedia materials) is a fundamentally innovative means of thinking and communicating are described. This representational architecture has many advantages that make it a major advance over other media; however, it also has several intrinsic problems that severly limits its effectiveness as a medium. These advantages and limits in applications are discussed.

  16. Holographic recording medium

    NASA Technical Reports Server (NTRS)

    Gange, Robert Allen (Inventor)

    1977-01-01

    A holographic recording medium comprising a conductive substrate, a photoconductive layer and an electrically alterable layer of a linear, low molecular weight hydrocarbon polymer has improved fatigue resistance. An acrylic barrier layer can be interposed between the photoconductive and electrically alterable layers.

  17. 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 sufficient 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 (Rifle, CO) in two continuous amendments separated by 5 days of groundwater flush 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 flush, 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 field conditions, in contrast to previous chemostat studies, suggesting that the function of a microbial community cannot be inferred based on lab experiments alone.

  18. Expression of acetate permease-like (apl) genes in subsurface communities of Geobacter species under fluctuating acetate concentrations

    SciTech Connect

    Elifantz, H.; N'Guessan, L.A.; Mouser, P.J.; Williams, K H.; Wilkins, M J.; Risso, C.; Holmes, D.E.; Long, P.E.; Lovley, D.R.

    2010-03-01

    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 sufficient 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 (Rifle, CO) in two continuous amendments separated by 5 days of groundwater flush 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 flush, 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 field conditions, in contrast to previous chemostat studies, suggesting that the function of a microbial community cannot be inferred based on lab experiments alone.

  19. An acetate bound cobalt oxide catalyst for water oxidation: role of monovalent anions and cations in lowering overpotential.

    PubMed

    Dey, Subal; Mondal, Biswajit; Dey, Abhishek

    2014-06-28

    A homogeneous solution of Co(II) in acetate buffer at pH 7 is found to be an efficient water oxidation catalyst (WOC) showing significantly greater current density than Co(II) in phosphate buffer (Co-Pi) under identical conditions owing to the higher solubility of the former. When electrodeposited on ITO/FTO electrodes it forms acetate bound cobalt(II)-oxide materials (Co-Ac-WOC) showing a catalytic current density of 0.1 mA cm(-2) at 830 mV and 1 mA cm(-2) at 1 V in a pH 7 buffer solution. The morphology of Co-Ac-WOC and its evolution with time and deposition potential is investigated with AFM, HR-TEM and SEM. The chemical composition of Co-Ac-WOC is investigated using XPS, EDX, ATR-FTIR and combustion analysis which indicate that this material has a CoO core with chloride and acetate anions bound to the Co center. Sodium is found to be integrated in the Co-Ac-WOC. The presence of the sodium and chloride ions lowers the onset potential for the oxygen evolution reaction (OER) by 240 mV relative to the classic Co-Pi at pH 7. The lower onset potential and higher OER current lowers the exchange current density to 10(-6.7) A cm(-2) in Co-Ac-WOC relative to 10(-8)-10(-10) A cm(-2) in Co-Pi and its derivatives.

  20. Separating acetic acid from furol (furfural) by electrodialysis method

    SciTech Connect

    Guan, S.F.; Li, C.S. Ye, S.T.; Shen, S.Y.; Wang, Y.T.; Yu, S.H.

    1981-01-01

    Furfural production by hydrolysis of fibrous plant materials is accompanied by formation of acetic acid in amounts depending on the material used. The amount of acetic formed in the hydrolysis of the fruit shell of oil-tea camellia (Camellia oleosa) (an oilseed-bearing tree) is equal to the amount of furfural. The acetic acid can be separated from the furfural and concentrated to 10% by electrodialysis. A smaller amount of furfural is separated with acetic acid.

  1. Gold-catalyzed cyclization of allenyl acetal derivatives

    PubMed Central

    Vasu, Dhananjayan; Pawar, Samir Kundlik

    2013-01-01

    Summary The gold-catalyzed transformation of allenyl acetals into 5-alkylidenecyclopent-2-en-1-ones is described. The outcome of our deuterium labeling experiments supports a 1,4-hydride shift of the resulting allyl cationic intermediates because a complete deuterium transfer is observed. We tested the reaction on various acetal substrates bearing a propargyl acetate, giving 4-methoxy-5-alkylidenecyclopent-2-en-1-ones 4 via a degradation of the acetate group at the allyl cation intermediate. PMID:24062838

  2. A wide bandwidth CCD buffer memory system

    NASA Technical Reports Server (NTRS)

    Siemens, K.; Wallace, R. W.; Robinson, C. R.

    1978-01-01

    A prototype system was implemented to demonstrate that CCD's can be applied advantageously to the problem of low power digital storage and particularly to the problem of interfacing widely varying data rates. CCD shift register memories (8K bit) were used to construct a feasibility model 128 K-bit buffer memory system. Serial data that can have rates between 150 kHz and 4.0 MHz can be stored in 4K-bit, randomly-accessible memory blocks. Peak power dissipation during a data transfer is less than 7 W, while idle power is approximately 5.4 W. The system features automatic data input synchronization with the recirculating CCD memory block start address. System expansion to accommodate parallel inputs or a greater number of memory blocks can be performed in a modular fashion. Since the control logic does not increase proportionally to increase in memory capacity, the power requirements per bit of storage can be reduced significantly in a larger system.

  3. Microbial Community Diversity in Agroforestry and Grass Buffer Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agroforesty and grass buffer systems have long been promoted as a soil conservation practice that yields many environmental benefits. Previous research has described the ability of buffer systems to retain nutrients, slow water flow and soil erosion, or mitigate the potentially harmful effects of e...

  4. Methods for improved growth of group III nitride buffer layers

    DOEpatents

    Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

    2014-07-15

    Methods are disclosed for growing high crystal quality group III-nitride epitaxial layers with advanced multiple buffer layer techniques. In an embodiment, a method includes forming group III-nitride buffer layers that contain aluminum on suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. A hydrogen halide or halogen gas is flowing into the growth zone during deposition of buffer layers to suppress homogeneous particle formation. Some combinations of low temperature buffers that contain aluminum (e.g., AlN, AlGaN) and high temperature buffers that contain aluminum (e.g., AlN, AlGaN) may be used to improve crystal quality and morphology of subsequently grown group III-nitride epitaxial layers. The buffer may be deposited on the substrate, or on the surface of another buffer. The additional buffer layers may be added as interlayers in group III-nitride layers (e.g., GaN, AlGaN, AlN).

  5. Current isolating epitaxial buffer layers for high voltage photodiode array

    DOEpatents

    Morse, Jeffrey D.; Cooper, Gregory A.

    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.

  6. Improved pH buffering agent for sodium hypochlorite

    NASA Technical Reports Server (NTRS)

    Nash, J. R.; Veeder, L. N.

    1969-01-01

    Sodium citrate/citric acid was found to be an effective buffer for pH control when used with sodium hypochlorite. The mixture does not corrode aluminum. The buffer appears to form a type of conversion coating that may provide corrosion-resistant properties to aluminum in other applications.

  7. Cyproterone acetate in treatment of precocious puberty.

    PubMed Central

    Kauli, R; Pertzelan, A; Prager-Lewin, R; Grünebaum, M; Laron, Z

    1976-01-01

    Twenty-nine children (23 girls, 6 boys) with precocious puberty were treated with cyproterone acetate for various periods of time ranging from 6 months to 3 years 4 months. They received an oral dose ranging from 70-150 mg/m2 per day, or an intramuscular depot injection once a fortnight or once a month at a dose ranging from 107-230 mg/m2. Both forms of therapy were found to suppress the signs of sexual maturation, but the oral form proved to be superior. Only the younger patients with a bone age under 11 years showed a beneficial effect upon linear growth and bone maturation. No side effects were noted, but additional advantageous effects upon behaviour and sociability were. It is concluded that at present cyproterone acetate by mouth is the drug of choice in the treatment of precocious puberty. The treatment should be initiated as early as possible to attain maximum benefit. PMID:952553

  8. 21 CFR 182.8892 - α-Tocopherol acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false α-Tocopherol acetate. 182.8892 Section 182.8892 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...-Tocopherol acetate. (a) Product. α-Tocopherol acetate. (b) Conditions of use. This substance is...

  9. 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…

  10. 21 CFR 182.8892 - α-Tocopherol acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true α-Tocopherol acetate. 182.8892 Section 182.8892 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...-Tocopherol acetate. (a) Product. α-Tocopherol acetate. (b) Conditions of use. This substance is...

  11. 21 CFR 182.8892 - α-Tocopherol acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false α-Tocopherol acetate. 182.8892 Section 182.8892 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...-Tocopherol acetate. (a) Product. α-Tocopherol acetate. (b) Conditions of use. This substance is...

  12. 21 CFR 582.5892 - a-Tocopherol acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false a-Tocopherol acetate. 582.5892 Section 582.5892 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5892 a-Tocopherol acetate. (a) Product. a-Tocopherol acetate. (b) Conditions of use....

  13. 21 CFR 582.5892 - a-Tocopherol acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false a-Tocopherol acetate. 582.5892 Section 582.5892 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5892 a-Tocopherol acetate. (a) Product. a-Tocopherol acetate. (b) Conditions of use....

  14. 21 CFR 182.8892 - α-Tocopherol acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false α-Tocopherol acetate. 182.8892 Section 182.8892...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8892 α-Tocopherol acetate. (a) Product. α-Tocopherol acetate. (b) Conditions of use. This substance is generally recognized as safe when used in...

  15. Acetate concentrations and oxidation in salt marsh sediments

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Acetate concentrations and rates of acetate oxidation and sulfate reduction were measured in S. alterniflora sediments in New Hampshire and Massachusetts. Pore water extracted from cores by squeezing or centrifugation contained in greater than 0.1 mM acetate and, in some instances, greater than 1.0 mM. Pore water sampled nondestructively contained much less acetate, often less than 0.01 mM. Acetate was associated with roots, and concentrations varied with changes in plant physiology. Acetate turnover was very low whether whole core or slurry incubations were used. Radiotracers injected directly into soils yielded rates of sulfate reduction and acetate oxidation not significantly different from core incubation techniques. Regardless of incubation method, acetate oxidation did not account for a substantial percentage of sulfate reduction. These results differ markedly from data for unvegetated coastal sediments where acetate levels are low, oxidation rate constants are high, and acetate oxication rates greatly exceed rates of sulfate reduction. The discrepancy between rates of acetate oxidation and sulfate reduction in these marsh soils may be due either to the utilization of substrates other than acetate by sulfate reducers or artifacts associated with measurements of organic utilization by rhizosphere bacteria. Care must be taken when interpreting data from salt marsh sediments since the release of material from roots during coring may affect the concentrations of certain compounds as well as influencing results obtained when sediment incubations are employed.

  16. 21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Ethyl alcohol containing ethyl acetate. The feed additive ethyl alcohol containing ethyl acetate meets the requirement of 27 CFR 21.62, being not less than 92.5 percent ethyl alcohol, each 100 gallons... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ethyl alcohol containing ethyl acetate....

  17. 21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Ethyl alcohol containing ethyl acetate. The feed additive ethyl alcohol containing ethyl acetate meets the requirement of 27 CFR 21.62, being not less than 92.5 percent ethyl alcohol, each 100 gallons... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ethyl alcohol containing ethyl acetate....

  18. 21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Ethyl alcohol containing ethyl acetate. The feed additive ethyl alcohol containing ethyl acetate meets the requirement of 27 CFR 21.62, being not less than 92.5 percent ethyl alcohol, each 100 gallons... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Ethyl alcohol containing ethyl acetate....

  19. 21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Ethyl alcohol containing ethyl acetate. The feed additive ethyl alcohol containing ethyl acetate meets the requirement of 27 CFR 21.62, being not less than 92.5 percent ethyl alcohol, each 100 gallons... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethyl alcohol containing ethyl acetate....

  20. 21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Ethyl alcohol containing ethyl acetate. The feed additive ethyl alcohol containing ethyl acetate meets the requirement of 27 CFR 21.62, being not less than 92.5 percent ethyl alcohol, each 100 gallons... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ethyl alcohol containing ethyl acetate....

  1. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Vitamin A acetate. 582.5933 Section 582.5933 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of use....

  2. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Vitamin A acetate. 582.5933 Section 582.5933 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of use....

  3. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Vitamin A acetate. 582.5933 Section 582.5933 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of use....

  4. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Vitamin A acetate. 582.5933 Section 582.5933 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of use....

  5. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Vitamin A acetate. 582.5933 Section 582.5933 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of use....

  6. 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.

  7. Mitigation of substrate defects in reticles using multilayer buffer layers

    DOEpatents

    Mirkarimi, Paul B.; Bajt, Sasa; Stearns, Daniel G.

    2001-01-01

    A multilayer film is used as a buffer layer to minimize the size of defects on a reticle substrate prior to deposition of a reflective coating on the substrate. The multilayer buffer layer deposited intermediate the reticle substrate and the reflective coating produces a smoothing of small particles and other defects on the reticle substrate. The reduction in defect size is controlled by surface relaxation during the buffer layer growth process and by the degree of intermixing and volume contraction of the materials at the multilayer interfaces. The buffer layers are deposited at near-normal incidence via a low particulate ion beam sputtering process. The growth surface of the buffer layer may also be heated by a secondary ion source to increase the degree of intermixing and improve the mitigation of defects.

  8. Replenishing data descriptors in a DMA injection FIFO buffer

    DOEpatents

    Archer, Charles J.; Blocksome, Michael A.; Cernohous, Bob R.; Heidelberger, Philip; Kumar, Sameer; Parker, Jeffrey J.

    2011-10-11

    Methods, apparatus, and products are disclosed for replenishing data descriptors in a Direct Memory Access (`DMA`) injection first-in-first-out (`FIFO`) buffer that include: determining, by a messaging module on an origin compute node, whether a number of data descriptors in a DMA injection FIFO buffer exceeds a predetermined threshold, each data descriptor specifying an application message for transmission to a target compute node; queuing, by the messaging module, a plurality of new data descriptors in a pending descriptor queue if the number of the data descriptors in the DMA injection FIFO buffer exceeds the predetermined threshold; establishing, by the messaging module, interrupt criteria that specify when to replenish the injection FIFO buffer with the plurality of new data descriptors in the pending descriptor queue; and injecting, by the messaging module, the plurality of new data descriptors into the injection FIFO buffer in dependence upon the interrupt criteria.

  9. Co-fermentation of acetate and sugars facilitating microbial lipid production on acetate-rich biomass hydrolysates.

    PubMed

    Gong, Zhiwei; Zhou, Wenting; Shen, Hongwei; Yang, Zhonghua; Wang, Guanghui; Zuo, Zhenyu; Hou, Yali; Zhao, Zongbao K

    2016-05-01

    The process of lignocellulosic biomass routinely produces a stream that contains sugars plus various amounts of acetic acid. As acetate is known to inhibit the culture of microorganisms including oleaginous yeasts, little attention has been paid to explore lipid production on mixtures of acetate and sugars. Here we demonstrated that the yeast Cryptococcus curvatus can effectively co-ferment acetate and sugars for lipid production. When mixtures of acetate and glucose were applied, C. curvatus consumed both substrates simultaneously. Similar phenomena were also observed for acetate and xylose mixtures, as well as acetate-rich corn stover hydrolysates. More interestingly, the replacement of sugar with equal amount of acetate as carbon source afforded higher lipid titre and lipid content. The lipid products had fatty acid compositional profiles similar to those of cocoa butter, suggesting their potential for high value-added fats and biodiesel production. This co-fermentation strategy should facilitate lipid production technology from lignocelluloses. PMID:26874438

  10. Stability of octreotide acetate in polypropylene syringes.

    PubMed

    Stiles, M L; Allen, L V; Resztak, K E; Prince, S J

    1993-11-01

    The stability of octreotide acetate in polypropylene syringes was studied. Polypropylene syringes were aseptically filled with 1 mL of octreotide acetate 0.2 mg/mL and stored at 3 or 23 degrees C under light protection or light exposure. Three syringes were prepared for each condition and each sampling time. Unopened 5-mL glass vials of the drug served as controls. Samples were removed immediately and at 8, 15, 22, and 29 days and analyzed by high-performance liquid chromatography. At 3 degrees C, octreotide stored in light-protected syringes maintained more than 90% of its initial concentration for up to 29 days. However, at 22 days the concentration in the syringes stored at that temperature and exposed to light was less than 90% when the standard deviation is considered. At 23 degrees C, the drug was stable for only up to 15 days (light protection) and 22 days (light exposure) when the standard deviation is considered. Octreotide acetate in polypropylene syringes was stable for up to 29 days when stored at 3 degrees C and protected from light and for up to 22 days when stored at 23 degrees C and exposed to light.

  11. Ultrasound-assisted dyeing of cellulose acetate.

    PubMed

    Udrescu, C; Ferrero, F; Periolatto, M

    2014-07-01

    The possibility of reducing the use of auxiliaries in conventional cellulose acetate dyeing with Disperse Red 50 using ultrasound technique was studied as an alternative to the standard procedure. Dyeing of cellulose acetate yarn was carried out by using either mechanical agitation alone, with and without auxiliaries, or coupling mechanical and ultrasound agitation in the bath where the temperature range was maintained between 60 and 80 °C. The best results of dyeing kinetics were obtained with ultrasound coupled with mechanical agitation without auxiliaries (90% of bath exhaustion value at 80 °C). Hence the corresponding half dyeing times, absorption rate constants according to Cegarra-Puente modified equation and ultrasound efficiency were calculated confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound added to mechanical agitation was evidenced by the lower value (48 kJ/mol) in comparison with 112 and 169 kJ/mol for mechanical stirring alone with auxiliaries and without, respectively. Finally, the fastness tests gave good values for samples dyed with ultrasound technique even without auxiliaries. Moreover color measurements on dyed yarns showed that the color yield obtained by ultrasound-assisted dyeing at 80 °C of cellulose acetate without using additional chemicals into the dye bath reached the same value yielded by mechanical agitation, but with remarkably shorter time.

  12. Acanthamoeba encystment: multifactorial effects of buffers, biocides, and demulcents present in contact lens care solutions

    PubMed Central

    Kovacs, Christopher J; Lynch, Shawn C; Rah, Marjorie J; Millard, Kimberly A; Morris, Timothy W

    2015-01-01

    Purpose To determine whether agents which are purportedly capable of inducing encystment of Acanthamoeba can recapitulate the signal when tested in differing formulations. Methods In accordance with the International Standard ISO 19045, Acanthamoeba castellanii ATCC 50370 trophozoites were cultured in antibiotic-free axenic medium, treated with test solutions, and encystment rates plus viability were measured via bright field and fluorescent microscopy. Test solutions included phosphate-buffered saline (PBS), borate-buffered saline, biguanide- and hydrogen peroxide (H2O2)-based biocides, propylene glycol (PG) and povidone (POV) ophthalmic demulcents, and one-step H2O2-based contact lens disinfection systems. Results Only PBS solutions with 0.25 ppm polyaminopropyl biguanide (PAPB) and increasing concentrations of PG and POV stimulated A. castellanii encystment in a dose-dependent manner, whereas PBS solutions containing 3% H2O2 and increasing concentrations of PG and POV did not stimulate encystment. Borate-buffered saline and PBS/citrate solutions containing PG also did not stimulate encystment. In addition, no encystment was observed after 24 hours, 7 days, or 14 days of exposures of trophozoites to one-step H2O2 contact lens disinfection products or related solutions. Conclusion The lack of any encystment observed when trophozoites were treated with existing or new one-step H2O2 contact lens care products, as well as when trophozoites were exposed to various related test solutions, confirms that Acanthamoeba encystment is a complex process which depends upon simultaneous contributions of multiple factors including buffers, biocides, and demulcents. PMID:26508829

  13. Leaching with Penicillium simplicissimum: Influence of metals and buffers on proton extrusion and citric acid production

    SciTech Connect

    Franz, A.; Burgstaller, W.; Schinner, F. )

    1991-03-01

    In the presence of insoluble metal oxides (industrial filter dust, zinc oxide, synthetic mixture of metal oxides), Penicillium simplicissimum developed the ability to excrete considerable amounts of citric acid (>100 mM). Parallel with the increase of citric acid concentration in the culture broth, zinc was solubilized from zinc oxide. The adsorption of filter dust onto the mycelium (the pellets formed were less than 1 mm in diameter) was required for not only the citric acid excretion but also the leaching of zinc. When the filter dust was replaced with a synthetic mixture of metal oxides or with zinc oxide in combination with trace elements, levels of adsorption and citric acid production were observed to be similar to those in experiments where industrial filter dust was used. The two most important properties of the filter dust were its heavy-metal content and its buffering capacity. These properties were simulated by adding heavy metals in soluble form (as chlorides, sulfates, or nitrates) or soluble buffers to the medium. Both heavy metals and buffers were not able to induce a citric acid efflux. As with citric acid production by Aspergillus niger, the addition of manganese lowered citric acid excretion (by 40% with metal oxide-induced citric acid efflux and by 100% with urea-induced citric acid efflux). Copper antagonized the effect of manganese. The mechanism for the bulk of citric acid excretion by P. simplicissimum, however, seemed to be different from that described for citric acid accumulation by A. niger. Because of the inefficiency of metals in solubilized form and of soluble buffers to induce a strong citric acid efflux, adsorption of an insoluble metal compound (zinc oxide) turned out to be essential.

  14. Statistical modeling of pullulan production and its application in pullulan acetate nanoparticles synthesis.

    PubMed

    Sugumaran, K R; Ponnusami, V

    2015-11-01

    This work focused on the optimization of exo-polysaccharide, pullulan production by exploiting cassava bagasse, an agricultural solid waste residue by solid state fermentation and its application in the preparation of pullulan acetate nanoparticles. Statistical approach was investigated to maximize the pullulan production using C/N ratio, initial pH, NaCl and ZnSO4·5H2O. The optimum conditions for maximum yield of pullulan (39.42±0.62mg/gds) were found to be: C/N=25.94, initial pH=5.5 and NaCl=0.55g/L. Using the optimized medium variables, the production of pullulan was investigated in lab scale solid state fermentation. The pullulan produced was characterized by thermo gravimetric and XRD analysis. Also pullulan acetate nanoparticles were synthesized from chemical modification of pullulan and the average particle size of nanoparticles was examined by zeta particle sizer.

  15. Visualization of Buffer Capacity with 3-D "Topo" Surfaces: Buffer Ridges, Equivalence Point Canyons and Dilution Ramps

    ERIC Educational Resources Information Center

    Smith, Garon C.; Hossain, Md Mainul

    2016-01-01

    BufCap TOPOS is free software that generates 3-D topographical surfaces ("topos") for acid-base equilibrium studies. It portrays pH and buffer capacity behavior during titration and dilution procedures. Topo surfaces are created by plotting computed pH and buffer capacity values above a composition grid with volume of NaOH as the x axis…

  16. 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

  17. Application of acetate, lactate, and fumarate as electron donors in microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Vasyliv, Oresta M.; Bilyy, Oleksandr I.; Ferensovych, Yaroslav P.; Hnatush, Svitlana O.

    2013-09-01

    Microbial fuel cells (MFCs) are devices that use bacteria as the catalysts to oxidize organic and inorganic matter and generate current. Up to now, several classes of extracellular electron transfer mechanisms have been elucidated for various microorganisms. Shewanellaceae and Geobacteraceae families include the most of model exoelectrogenic microorganisms. Desulfuromonas acetoxidans bacterium inhabits aquatic sedimental sulfur-containing environments and is philogenetically close to representatives of Geobacteraceae family. Two chamber microbial fuel cell (0.3 l volume) was constructed with application of D. acetoxidans IMV B-7384 as anode biocatalyst. Acetic, lactic and fumaric acids were separately applied as organic electron donors for bacterial growth in constructed MFC. Bacterial cultivation in MFC was held during twenty days. Lactate oxidation caused electric power production with the highest value up to 0.071 mW on 64 hour of D. acetoxidans IMV B-7384 growth. Addition of acetic and fumaric acids into bacterial growth medium caused maximal power production up to 0.075 and 0.074 mW respectively on the 40 hour of their growth. Increasing of incubation time up to twentieth day caused decrease of generated electric power till 0.018 mW, 0.042 mW and 0.047 mW under usage of lactic, acetic and fumaric acids respectively by investigated bacteria. Power generation by D. acetoxidans IMV B-7384 was more stabile and durable under application of acetic and fumaric acids as electron donors in constructed MFC, than under addition of lactic acid in the same concentration into the growth medium.

  18. Zebrafish as a Model for Systems Medicine R&D: Rethinking the Metabolic Effects of Carrier Solvents and Culture Buffers Determined by (1)H NMR Metabolomics.

    PubMed

    Akhtar, Muhammad T; Mushtaq, Mian Y; Verpoorte, Robert; Richardson, Michael K; Choi, Young H

    2016-01-01

    Zebrafish is a frequently employed model organism in systems medicine and biomarker discovery. A crosscutting fundamental question, and one that has been overlooked in the field, is the "system-wide" (omics) effects induced in zebrafish by metabolic solvents and culture buffers. Indeed, any bioactivity or toxicity test requires that the target compounds are dissolved in an appropriate nonpolar solvent or aqueous media. It is important to know whether the solvent or the buffer itself has an effect on the zebrafish model organism. We evaluated the effects of two organic carrier solvents used in research with zebrafish, as well as in drug screening: dimethyl sulfoxide (DMSO) and ethanol, and two commonly used aqueous buffers (egg water and Hank's balanced salt solution). The effects of three concentrations (0.01, 0.1, and 1%) of DMSO and ethanol were tested in the 5-day-old zebrafish embryo using proton nuclear magnetic resonance ((1)H NMR) based metabolomics. DMSO (1% and 0.1%, but not 0.01%) exposure significantly decreased the levels of adenosine triphosphate (ATP), betaine, alanine, histidine, lactate, acetate, and creatine (p < 0.05). By contrast, ethanol exposure did not alter the embryos' metabolome at any concentration tested. The two different aqueous media noted above impacted the zebrafish embryo metabolome as evidenced by changes in valine, alanine, lactate, acetate, betaine, glycine, glutamate, adenosine triphosphate, and histidine. These results show that DMSO has greater effects on the embryo metabolome than ethanol, and thus is used with caution as a carrier solvent in zebrafish biomarker research and oral medicine. Moreover, the DMSO concentration should not be higher than 0.01%. Careful attention is also warranted for the use of the buffers egg water and Hank's balanced salt solution in zebrafish. In conclusion, as zebrafish is widely used as a model organism in life sciences, metabolome changes induced by solvents and culture buffers warrant further

  19. Multiple cytosolic calcium buffers in posterior pituitary nerve terminals.

    PubMed

    McMahon, Shane M; Chang, Che-Wei; Jackson, Meyer B

    2016-03-01

    Cytosolic Ca(2+) buffers bind to a large fraction of Ca(2+) as it enters a cell, shaping Ca(2+) signals both spatially and temporally. In this way, cytosolic Ca(2+) buffers regulate excitation-secretion coupling and short-term plasticity of release. The posterior pituitary is composed of peptidergic nerve terminals, which release oxytocin and vasopressin in response to Ca(2+) entry. Secretion of these hormones exhibits a complex dependence on the frequency and pattern of electrical activity, and the role of cytosolic Ca(2+) buffers in controlling pituitary Ca(2+) signaling is poorly understood. Here, cytosolic Ca(2+) buffers were studied with two-photon imaging in patch-clamped nerve terminals of the rat posterior pituitary. Fluorescence of the Ca(2+) indicator fluo-8 revealed stepwise increases in free Ca(2+) after a series of brief depolarizing pulses in rapid succession. These Ca(2+) increments grew larger as free Ca(2+) rose to saturate the cytosolic buffers and reduce the availability of Ca(2+) binding sites. These titration data revealed two endogenous buffers. All nerve terminals contained a buffer with a Kd of 1.5-4.7 µM, and approximately half contained an additional higher-affinity buffer with a Kd of 340 nM. Western blots identified calretinin and calbindin D28K in the posterior pituitary, and their in vitro binding properties correspond well with our fluorometric analysis. The high-affinity buffer washed out, but at a rate much slower than expected from diffusion; washout of the low-affinity buffer could not be detected. This work has revealed the functional impact of cytosolic Ca(2+) buffers in situ in nerve terminals at a new level of detail. The saturation of these cytosolic buffers will amplify Ca(2+) signals and may contribute to use-dependent facilitation of release. A difference in the buffer compositions of oxytocin and vasopressin nerve terminals could contribute to the differences in release plasticity of these two hormones. PMID:26880753

  20. Multiple cytosolic calcium buffers in posterior pituitary nerve terminals

    PubMed Central

    McMahon, Shane M.; Chang, Che-Wei

    2016-01-01

    Cytosolic Ca2+ buffers bind to a large fraction of Ca2+ as it enters a cell, shaping Ca2+ signals both spatially and temporally. In this way, cytosolic Ca2+ buffers regulate excitation-secretion coupling and short-term plasticity of release. The posterior pituitary is composed of peptidergic nerve terminals, which release oxytocin and vasopressin in response to Ca2+ entry. Secretion of these hormones exhibits a complex dependence on the frequency and pattern of electrical activity, and the role of cytosolic Ca2+ buffers in controlling pituitary Ca2+ signaling is poorly understood. Here, cytosolic Ca2+ buffers were studied with two-photon imaging in patch-clamped nerve terminals of the rat posterior pituitary. Fluorescence of the Ca2+ indicator fluo-8 revealed stepwise increases in free Ca2+ after a series of brief depolarizing pulses in rapid succession. These Ca2+ increments grew larger as free Ca2+ rose to saturate the cytosolic buffers and reduce the availability of Ca2+ binding sites. These titration data revealed two endogenous buffers. All nerve terminals contained a buffer with a Kd of 1.5–4.7 µM, and approximately half contained an additional higher-affinity buffer with a Kd of 340 nM. Western blots identified calretinin and calbindin D28K in the posterior pituitary, and their in vitro binding properties correspond well with our fluorometric analysis. The high-affinity buffer washed out, but at a rate much slower than expected from diffusion; washout of the low-affinity buffer could not be detected. This work has revealed the functional impact of cytosolic Ca2+ buffers in situ in nerve terminals at a new level of detail. The saturation of these cytosolic buffers will amplify Ca2+ signals and may contribute to use-dependent facilitation of release. A difference in the buffer compositions of oxytocin and vasopressin nerve terminals could contribute to the differences in release plasticity of these two hormones. PMID:26880753

  1. Improved Stability of a Model IgG3 by DoE-Based Evaluation of Buffer Formulations.

    PubMed

    Chavez, Brittany K; Agarabi, Cyrus D; Read, Erik K; Boyne, Michael T; Khan, Mansoor A; Brorson, Kurt A

    2016-01-01

    Formulating appropriate storage conditions for biopharmaceutical proteins is essential for ensuring their stability and thereby their purity, potency, and safety over their shelf-life. Using a model murine IgG3 produced in a bioreactor system, multiple formulation compositions were systematically explored in a DoE design to optimize the stability of a challenging antibody formulation worst case. The stability of the antibody in each buffer formulation was assessed by UV/VIS absorbance at 280 nm and 410 nm and size exclusion high performance liquid chromatography (SEC) to determine overall solubility, opalescence, and aggregate formation, respectively. Upon preliminary testing, acetate was eliminated as a potential storage buffer due to significant visible precipitate formation. An additional 2(4) full factorial DoE was performed that combined the stabilizing effect of arginine with the buffering capacity of histidine. From this final DoE, an optimized formulation of 200 mM arginine, 50 mM histidine, and 100 mM NaCl at a pH of 6.5 was identified to substantially improve stability under long-term storage conditions and after multiple freeze/thaw cycles. Thus, our data highlights the power of DoE based formulation screening approaches even for challenging monoclonal antibody molecules. PMID:27042659

  2. Improved Stability of a Model IgG3 by DoE-Based Evaluation of Buffer Formulations

    PubMed Central

    Chavez, Brittany K.; Agarabi, Cyrus D.; Read, Erik K.; Boyne II, Michael T.; Khan, Mansoor A.; Brorson, Kurt A.

    2016-01-01

    Formulating appropriate storage conditions for biopharmaceutical proteins is essential for ensuring their stability and thereby their purity, potency, and safety over their shelf-life. Using a model murine IgG3 produced in a bioreactor system, multiple formulation compositions were systematically explored in a DoE design to optimize the stability of a challenging antibody formulation worst case. The stability of the antibody in each buffer formulation was assessed by UV/VIS absorbance at 280 nm and 410 nm and size exclusion high performance liquid chromatography (SEC) to determine overall solubility, opalescence, and aggregate formation, respectively. Upon preliminary testing, acetate was eliminated as a potential storage buffer due to significant visible precipitate formation. An additional 24 full factorial DoE was performed that combined the stabilizing effect of arginine with the buffering capacity of histidine. From this final DoE, an optimized formulation of 200 mM arginine, 50 mM histidine, and 100 mM NaCl at a pH of 6.5 was identified to substantially improve stability under long-term storage conditions and after multiple freeze/thaw cycles. Thus, our data highlights the power of DoE based formulation screening approaches even for challenging monoclonal antibody molecules. PMID:27042659

  3. Liquid chromatographic extraction medium

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1994-01-01

    A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

  4. Liquid chromatographic extraction medium

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1994-09-13

    A method and apparatus are disclosed for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water. 1 fig.

  5. Overview on mechanisms of acetic acid resistance in acetic acid bacteria.

    PubMed

    Wang, Bin; Shao, Yanchun; Chen, Fusheng

    2015-02-01

    Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided.

  6. 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

  7. 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

  8. Differential titration of bases in glacial acetic acid.

    PubMed

    Castellano, T; Medwick, T; Shinkai, J H; Bailey, L

    1981-01-01

    A study of bases in acetic acid and their differential titration was carried out. The overall basicity constants for 20 bases were measured in acetic acid, and the differential titration of five binary mixtures of variable delta pKb values in acetic acid was followed using a glass electrode-modified calomel electrode system. Agreement with literature values was good. A leveling diagram was constructed that indicated that bases stronger than aqueous pKb 10 are leveled to an acetous pKb 5.69, whereas weaker bases are not leveled but instead exhibit their own intrinsic basicity, with the acetous pKb to aqueous pKb values being linearly related (slope 1.18, correlation coefficient 0.962). A minimum acetous delta pKb of four units is required for the satisfactory differential titration of two bases in acetic acid.

  9. [Degradation of oxytetracycline with ozonation in acetic acid solvent].

    PubMed

    Li, Shi-Yin; Li, Xiao-Rong; Zhu, Yi-Ping; Zhu, Jiang-Peng; Wang, Guo-Xiang

    2012-12-01

    Use acetic acid as the media of ozone degradation of oxytetracycline (OTC), and effects of the initial dosing ratio of ozone/OTC, ozone flow, free radical scavenger, metal ions on the removal rate of OTC were investigated respectively. The results showed that acetic acid had a high ozone stability and solubility. OTC had a high removal rate and degradation rate in acetic acid solution. With the increase of OTC dosage, the removal rate of OTC decreased in acetic acid. Removal rate of OTC was increased distinctly when ozone flow increased properly. It was also observed that free radical scavenger had a significantly negative effect on OTC ozonation degradation in acetic acid. Furthermore the main reactions of OTC ozone oxidation were direct oxidation and indirect oxidation in acetic acid. When Fe3+ and Co2+ were existent in acetic acid, the degradation of OTC was inhibited significantly.

  10. Monitoring Liverworts to Evaluate the Effectiveness of Hydroriparian Buffers

    NASA Astrophysics Data System (ADS)

    Higgins, Kellina L.; Yasué, Maï

    2014-01-01

    In the coastal temperate rainforest of British Columbia (BC) in western Canada, government policies stipulate that foresters leave unlogged hydroriparian buffer strips up to 25 m on each side of streams to protect wildlife habitat. At present, studies on the effectiveness of these buffers focus on mammals, birds, and amphibians while there is comparably little information on smaller organisms such as liverworts in these hydroriparian buffers. To address this gap of knowledge, we conducted field surveys of liverworts comparing the percent cover and community composition in hydroriparian forested areas ( n = 4 sites, n = 32 plots with nested design) to hydroriparian buffer zones ( n = 4 sites, n = 32 plots). We also examined how substrate type affected the cover of liverworts. Liverwort communities in buffers were similar to those in riparian forest areas and most liverworts were found on downed wood. Thus, hydroriparian buffers of 25-35 m on each side in a coastal temperate rainforest effectively provide habitat for liverworts as long as downed wood is left intact in the landscape. Because liverworts are particularly sensitive to changes in humidity, these results may indicate that hydroriparian buffers are an effective management strategy for bryophytes and possibly for a range of other riparian species that are particularly sensitive to forestry-related changes in microclimate.

  11. Improved ultrastructure of marine invertebrates using non-toxic buffers.

    PubMed

    Montanaro, Jacqueline; Gruber, Daniela; Leisch, Nikolaus

    2016-01-01

    Many marine biology studies depend on field work on ships or remote sampling locations where sophisticated sample preservation techniques (e.g., high-pressure freezing) are often limited or unavailable. Our aim was to optimize the ultrastructural preservation of marine invertebrates, especially when working in the field. To achieve chemically-fixed material of the highest quality, we compared the resulting ultrastructure of gill tissue of the mussel Mytilus edulis when fixed with differently buffered EM fixatives for marine specimens (seawater, cacodylate and phosphate buffer) and a new fixative formulation with the non-toxic PHEM buffer (PIPES, HEPES, EGTA and MgCl2). All buffers were adapted for immersion fixation to form an isotonic fixative in combination with 2.5% glutaraldehyde. We showed that PHEM buffer based fixatives resulted in equal or better ultrastructure preservation when directly compared to routine standard fixatives. These results were also reproducible when extending the PHEM buffered fixative to the fixation of additional different marine invertebrate species, which also displayed excellent ultrastructural detail. We highly recommend the usage of PHEM-buffered fixation for the fixation of marine invertebrates. PMID:27069800

  12. Molecular Buffers Permit Sensitivity Tuning and Inversion of Riboswitch Signals.

    PubMed

    Rugbjerg, Peter; Genee, Hans Jasper; Jensen, Kristian; Sarup-Lytzen, Kira; Sommer, Morten Otto Alexander

    2016-07-15

    Predictable integration of foreign biological signals and parts remains a key challenge in the systematic engineering of synthetic cellular actuations, and general methods to improve signal transduction and sensitivity are needed. To address this problem we modeled and built a molecular signal buffer network in Saccharomyces cerevisiae inspired by chemical pH buffer systems. The molecular buffer system context-insulates a riboswitch enabling synthetic control of colony formation and modular signal manipulations. The riboswitch signal is relayed to a transcriptional activation domain of a split transcription factor, while interacting DNA-binding domains mediate the transduction of signal and form an interacting molecular buffer. The molecular buffer system enables modular signal inversion through integration with repressor modules. Further, tuning of input sensitivity was achieved through perturbation of the buffer pair ratio guided by a mathematical model. Such buffered signal tuning networks will be useful for domestication of RNA-based sensors enabling tunable outputs and library-wide selections for drug discovery and metabolic engineering. PMID:27138234

  13. Gilliam County Riparian Buffers; 2003-2004 Annual Reports.

    SciTech Connect

    Coiner, Josh

    2004-06-01

    Interest appears to be at an all-time high for riparian conservation programs in Gilliam County. With the recently added Herbaceous Buffer and the already established CREP program interest is booming. However, more and more people are turning towards the herbaceous buffer because of expense. The riparian forest buffer is becoming too expensive. Even with the excellent cost share and incentives landowners are having trouble with Farm Service Agency's payment limitation. Because of this payment limitation landowners are not receiving their full rental and incentive payments, usually in year one. This has cooled the installation of riparian forest buffers and peaked interest in the CP-29 (Herbaceous Buffer for Wildlife). Either way, riparian lands are being enhanced and water quality is being improved. Year three should be very similar to the accomplishments of year 2. There has already been several projects proposed that may or may not be approved during year 3. I am currently working on three projects that are all over 2.5 miles long on each side and total anywhere from 60 to 250 acres in size. Along with these three projects there at least seven small projects being proposed. Four of those projects are riparian forest buffers and the remaining are herbaceous buffers.

  14. Improved ultrastructure of marine invertebrates using non-toxic buffers

    PubMed Central

    Montanaro, Jacqueline; Gruber, Daniela

    2016-01-01

    Many marine biology studies depend on field work on ships or remote sampling locations where sophisticated sample preservation techniques (e.g., high-pressure freezing) are often limited or unavailable. Our aim was to optimize the ultrastructural preservation of marine invertebrates, especially when working in the field. To achieve chemically-fixed material of the highest quality, we compared the resulting ultrastructure of gill tissue of the mussel Mytilus edulis when fixed with differently buffered EM fixatives for marine specimens (seawater, cacodylate and phosphate buffer) and a new fixative formulation with the non-toxic PHEM buffer (PIPES, HEPES, EGTA and MgCl2). All buffers were adapted for immersion fixation to form an isotonic fixative in combination with 2.5% glutaraldehyde. We showed that PHEM buffer based fixatives resulted in equal or better ultrastructure preservation when directly compared to routine standard fixatives. These results were also reproducible when extending the PHEM buffered fixative to the fixation of additional different marine invertebrate species, which also displayed excellent ultrastructural detail. We highly recommend the usage of PHEM-buffered fixation for the fixation of marine invertebrates. PMID:27069800

  15. Monitoring liverworts to evaluate the effectiveness of hydroriparian buffers.

    PubMed

    Higgins, Kellina L; Yasué, Maï

    2014-01-01

    In the coastal temperate rainforest of British Columbia (BC) in western Canada, government policies stipulate that foresters leave unlogged hydroriparian buffer strips up to 25 m on each side of streams to protect wildlife habitat. At present, studies on the effectiveness of these buffers focus on mammals, birds, and amphibians while there is comparably little information on smaller organisms such as liverworts in these hydroriparian buffers. To address this gap of knowledge, we conducted field surveys of liverworts comparing the percent cover and community composition in hydroriparian forested areas (n = 4 sites, n = 32 plots with nested design) to hydroriparian buffer zones (n = 4 sites, n = 32 plots). We also examined how substrate type affected the cover of liverworts. Liverwort communities in buffers were similar to those in riparian forest areas and most liverworts were found on downed wood. Thus, hydroriparian buffers of 25-35 m on each side in a coastal temperate rainforest effectively provide habitat for liverworts as long as downed wood is left intact in the landscape. Because liverworts are particularly sensitive to changes in humidity, these results may indicate that hydroriparian buffers are an effective management strategy for bryophytes and possibly for a range of other riparian species that are particularly sensitive to forestry-related changes in microclimate.

  16. Buffer Gas Experiments in Mercury (Hg+) Ion Clock

    NASA Technical Reports Server (NTRS)

    Chung, Sang K.; Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute

    2004-01-01

    We describe the results of the frequency shifts measured from various buffer gases that might be used as a buffer gas to increase the loading efficiency and cooling of ions trapped in a small mercury ion clock. The small mass, volume and power requirement of space clock precludes the use of turbo pumps. Hence, a hermetically sealed vacuum system, incorporating a suitable getter material with a fixed amount of inert buffer gas may be a practical alternative to the groundbased system. The collision shifts of 40,507,347.996xx Hz clock transition for helium, neon and argon buffer gases were measured in the ambient earth magnetic field. In addition to the above non-getterable inert gases we also measured the frequency shifts due to getterable, molecular hydrogen and nitrogen gases which may be used as buffer gases when incorporated with a miniature ion pump. We also examined the frequency shift due to the low methane gas partial pressure in a fixed higher pressure neon buffer gas environment. Methane gas interacted with mercury ions in a peculiar way as to preserve the ion number but to relax the population difference in the two hyperfine clock states and thereby reducing the clock resonance signal. The same population relaxation was also observed for other molecular buffer gases (N H,) but at much reduced rate.

  17. Molecular Buffers Permit Sensitivity Tuning and Inversion of Riboswitch Signals

    PubMed Central

    2016-01-01

    Predictable integration of foreign biological signals and parts remains a key challenge in the systematic engineering of synthetic cellular actuations, and general methods to improve signal transduction and sensitivity are needed. To address this problem we modeled and built a molecular signal buffer network in Saccharomyces cerevisiae inspired by chemical pH buffer systems. The molecular buffer system context-insulates a riboswitch enabling synthetic control of colony formation and modular signal manipulations. The riboswitch signal is relayed to a transcriptional activation domain of a split transcription factor, while interacting DNA-binding domains mediate the transduction of signal and form an interacting molecular buffer. The molecular buffer system enables modular signal inversion through integration with repressor modules. Further, tuning of input sensitivity was achieved through perturbation of the buffer pair ratio guided by a mathematical model. Such buffered signal tuning networks will be useful for domestication of RNA-based sensors enabling tunable outputs and library-wide selections for drug discovery and metabolic engineering. PMID:27138234

  18. Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation.

    PubMed

    Aghazadeh, Mahdieh; Ladisch, Michael R; Engelberth, Abigail S

    2016-07-01

    Acetic acid is introduced into cellulose conversion processes as a consequence of composition of lignocellulose feedstocks, causing significant inhibition of adapted, genetically modified and wild-type S. cerevisiae in bioethanol fermentation. While adaptation or modification of yeast may reduce inhibition, the most effective approach is to remove the acetic acid prior to fermentation. This work addresses liquid-liquid extraction of acetic acid from biomass hydrolysate through a pathway that mitigates acetic acid inhibition while avoiding the negative effects of the extractant, which itself may exhibit inhibition. Candidate solvents were selected using simulation results from Aspen Plus™, based on their ability to extract acetic acid which was confirmed by experimentation. All solvents showed varying degrees of toxicity toward yeast, but the relative volatility of ethyl acetate enabled its use as simple vacuum evaporation could reduce small concentrations of aqueous ethyl acetate to minimally inhibitory levels. The toxicity threshold of ethyl acetate, in the presence of acetic acid, was found to be 10 g L(-1) . The fermentation was enhanced by extracting 90% of the acetic acid using ethyl acetate, followed by vacuum evaporation to remove 88% removal of residual ethyl acetate along with 10% of the broth. NRRL Y-1546 yeast was used to demonstrate a 13% increase in concentration, 14% in ethanol specific production rate, and 11% ethanol yield. This study demonstrated that extraction of acetic acid with ethyl acetate followed by evaporative removal of ethyl acetate from the raffinate phase has potential to significantly enhance ethanol fermentation in a corn stover bioethanol facility. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:929-937, 2016.

  19. Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation.

    PubMed

    Aghazadeh, Mahdieh; Ladisch, Michael R; Engelberth, Abigail S

    2016-07-01

    Acetic acid is introduced into cellulose conversion processes as a consequence of composition of lignocellulose feedstocks, causing significant inhibition of adapted, genetically modified and wild-type S. cerevisiae in bioethanol fermentation. While adaptation or modification of yeast may reduce inhibition, the most effective approach is to remove the acetic acid prior to fermentation. This work addresses liquid-liquid extraction of acetic acid from biomass hydrolysate through a pathway that mitigates acetic acid inhibition while avoiding the negative effects of the extractant, which itself may exhibit inhibition. Candidate solvents were selected using simulation results from Aspen Plus™, based on their ability to extract acetic acid which was confirmed by experimentation. All solvents showed varying degrees of toxicity toward yeast, but the relative volatility of ethyl acetate enabled its use as simple vacuum evaporation could reduce small concentrations of aqueous ethyl acetate to minimally inhibitory levels. The toxicity threshold of ethyl acetate, in the presence of acetic acid, was found to be 10 g L(-1) . The fermentation was enhanced by extracting 90% of the acetic acid using ethyl acetate, followed by vacuum evaporation to remove 88% removal of residual ethyl acetate along with 10% of the broth. NRRL Y-1546 yeast was used to demonstrate a 13% increase in concentration, 14% in ethanol specific production rate, and 11% ethanol yield. This study demonstrated that extraction of acetic acid with ethyl acetate followed by evaporative removal of ethyl acetate from the raffinate phase has potential to significantly enhance ethanol fermentation in a corn stover bioethanol facility. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:929-937, 2016. PMID:27090191

  20. Porphyrin derivatives from a recombinant Escherichia coli grown on chemically defined medium.

    PubMed

    Lee, Min Ju; Chun, Se-Jin; Kim, Hye-Jung; Kwon, An Sung; Jun, Soo Youn; Kang, Sang Hyeon; Kim, Pil

    2012-12-01

    We have reported previously that a recombinant Escherichia coli co-expresses aminolevulinic acid (ALA) synthase, an NADP-dependent malic enzyme, and a dicarboxylate transporter-produced heme, an iron-chelated porphyrin, in a succinate-containing complex medium. To develop an industrially plausible process, a chemically defined medium was formulated based on M9 minimal medium. Heme synthesis was enhanced by adding sodium bicarbonate, which strengthened the C4 metabolism required for the precursor metabolite, although a pH change discouraged cell growth. Increasing the medium pH buffering capacity (100mM phosphate buffer) and adding sodium bicarbonate enabled the recombinant E. coli to produce heme at rates 60% greater than those in M9 minimal medium. Adding growth factors (1 mg/l thiamin, 0.01 mg/l biotin, 5 mg/l nicotinic acid, 1 mg/l pantothenic acid, and 1.4 mg/l cobalamin) also induced positive heme production effects at levels twice of heme production in M9-based medium. Porphyrin derivatives and heme were found in the chemically defined medium, and their presence was confirmed by liquid chromatography/mass spectroscopy (LC/MS). The formulated medium allowed for the production of 0.6 microM heme, 29 microM ALA, 0.07 microM coproporphyrin I, 0.21 microM coproporphyrin III, and 0.23 microM uroporphyrin in a 3 L pH-controlled culture. PMID:23221527

  1. Root-uptake of (14)C derived from acetic acid and (14)C transfer to rice edible parts.

    PubMed

    Ogiyama, Shinichi; Suzuki, Hiroyuki; Inubushi, Kazuyuki; Takeda, Hiroshi; Uchida, Shigeo

    2010-02-01

    Three types of culture experiments using paddy rice (Oryza sativa L.) were performed to examine root-uptake of (14)C in the form of acetic acid: double pot experiment (hydroponics), wet culture experiment (submerged sand medium), and chamber experiment (hydroponics and submerged sand medium). The (14)C radioactivity in the plant, mediums, and atmospheric carbon dioxide ((14)CO(2)) in the chamber were determined, and the distribution of (14)C in the plant was visualized using autoradiography. In the double pot experiment, the shoot of the plant and the lower root which was soaked in the culture solution had (14)C radioactivity, but the upper root which did not have contact with the solution had none. There were also (14)C radioactivity in the grains and roots in the wet culture experiment. Results of the chamber experiment showed that (14)CO(2) gas was released from the culture solution in both types of cultures. Results indicated that the (14)C-acetic acid absorbed by rice plant through its root would be very small. Most of the (14)C-acetic acid was transformed into gaseous forms either in the culture solution or rhizosphere. A relatively longer time would be needed to assimilate (14)C derived from acetic acid to grain parts after it was once absorbed by the shoot through the root. Availability of (14)C for the plant in sand culture was considered to be decreased compared with that for the plant in the hydroponics experiment. It was suggested that rice plant absorbed and assimilated (14)C through the plant roots not because of uptake of (14)C-acetic acid but because of uptake of (14)C in gaseous forms such as (14)CO(2). PMID:19962904

  2. Wasco Riparian Buffer Project, Annual Report 2003-2004.

    SciTech Connect

    Graves, Ron

    2003-07-01

    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 buffer contracts were established on 173,462 ft. of stream (25.9 miles). Acreage included in the buffers totaled 891.6 acres. Average buffer width was 112 ft. on each side of the stream. Cumulative totals through the first two project years are 26 buffers on 36.6 stream miles covering 1,283.6 acres. Actual implementation costs, lease payments, and maintenance costs will be borne by existing USDA programs: Conservation Reserve (CRP) and Conservation Reserve Enhancement Programs (CREP). The lease period of each contract may vary from 10 to 15 years. During this year, the average lease period was 14.9 years. The total value of contracts established this year is $1,421,268 compared with $55,504 in BPA contract costs to provide the technical support needed to get the contracts implemented. Cumulative contract value for the first two years is $1,919,451 compared to $103,329 cost to BPA. This project provides technical staffing to conduct assessments and develop conservation plans required for riparian buffer systems to help keep pace with a growing backlog of potential buffer projects. This project meets a critical need in the lower Deschutes and lower John Day River basins and complements the Riparian Buffer project approved for Fifteenmile watershed, Project No. 2001-021-00 begun in fiscal year 2001. This project supports RPA 150 and 153 as required under the Federal Hydropower System biological opinion and benefits the mid-Columbia ESU of steelhead.

  3. Job Shop Scheduling Focusing on Role of Buffer

    NASA Astrophysics Data System (ADS)

    Hino, Rei; Kusumi, Tetsuya; Yoo, Jae-Kyu; Shimizu, Yoshiaki

    A scheduling problem is formulated in order to consistently manage each manufacturing resource, including machine tools, assembly robots, AGV, storehouses, material shelves, and so on. The manufacturing resources are classified into three types: producer, location, and mover. This paper focuses especially on the role of the buffer, and the differences among these types are analyzed. A unified scheduling formulation is derived from the analytical results based on the resource’s roles. Scheduling procedures based on dispatching rules are also proposed in order to numerically evaluate job shop-type production having finite buffer capacity. The influences of the capacity of bottle-necked production devices and the buffer on productivity are discussed.

  4. Buffer layers for REBCO films for use in superconducting devices

    SciTech Connect

    Goyal, Amit; Wee, Sung-Hun

    2014-06-10

    A superconducting article includes a substrate having a biaxially textured surface. A biaxially textured buffer layer, which can be a cap layer, is supported by the substrate. The buffer layer includes a double perovskite of the formula A.sub.2B'B''O.sub.6, where A is rare earth or alkaline earth metal and B' and B'' are different transition metal cations. A biaxially textured superconductor layer is deposited so as to be supported by the buffer layer. A method of making a superconducting article is also disclosed.

  5. Enhanced adhesion for LIGA microfabrication by using a buffer layer

    DOEpatents

    Bajikar, Sateesh S.; De Carlo, Francesco; Song, Joshua J.

    2001-01-01

    The present invention is an improvement on the LIGA microfabrication process wherein a buffer layer is applied to the upper or working surface of a substrate prior to the placement of a resist onto the surface of the substrate. The buffer layer is made from an inert low-Z material (low atomic weight), a material that absorbs secondary X-rays emissions from the substrate that are generated from the substrate upon exposure to a primary X-rays source. Suitable materials for the buffer layer include polyamides and polyimide. The preferred polyimide is synthesized form pyromellitic anhydride and oxydianiline (PMDA-ODA).

  6. Enhanced adhesion for LIGA microfabrication by using a buffer layer

    DOEpatents

    Bajikar, Sateesh S.; De Carlo, Francesco; Song, Joshua J.

    2004-01-27

    The present invention is an improvement on the LIGA microfabrication process wherein a buffer layer is applied to the upper or working surface of a substrate prior to the placement of a resist onto the surface of the substrate. The buffer layer is made from an inert low-Z material (low atomic weight), a material that absorbs secondary X-rays emissions from the substrate that are generated from the substrate upon exposure to a primary X-rays source. Suitable materials for the buffer layer include polyamides and polyimide. The preferred polyimide is synthesized form pyromellitic anhydride and oxydianiline (PMDA-ODA).

  7. An oxygen buffer for some peraluminous granites and metamorphic rocks.

    USGS Publications Warehouse

    Zen, E.

    1985-01-01

    The mineral assemblage biotite-garnet-muscovite-magnetite-quartz and its sub-sets are common in many peraluminous granites, schists and gneisses. If the biotite and garnet are reasonably iron-rich, then the system is a useful buffer for fO2. Available thermochemical data indicate that, in T-fO2 space, the buffer curve is located between the hematite-magnetite curve and the quartz-magnetite-fayalite curve, in a region that previously had no buffer curve applicable to peraluminous rocks. -J.A.Z.

  8. Buffer layer effect on ZnO nanorods growth alignment

    NASA Astrophysics Data System (ADS)

    Zhao, Dongxu; Andreazza, Caroline; Andreazza, Pascal; Ma, Jiangang; Liu, Yichun; Shen, Dezhen

    2005-06-01

    Vertical aligned ZnO nanorods array was fabricated on Si with introducing a ZnO thin film as a buffer layer. Two different nucleation mechanisms were found in growth process. With using Au catalyst, Zn vapor could diffuse into Au nanoclusters with forming a solid solution. Then the ZnO nucleation site is mainly on the catalyst by oxidation of Au/Zn alloy. Without catalyst, nucleation could occur directly on the surface of buffer layer by homoepitaxy. The density and the size of ZnO nanorods could be governed by morphological character of catalyst and buffer layer. The nanorods growth is followed by vapor-solid mechanism.

  9. Agar Medium for Differential Enumeration of Lactic Streptococci1

    PubMed Central

    Reddy, M. S.; Vedamuthu, E. R.; Washam, C. J.; Reinbold, G. W.

    1972-01-01

    An agar medium containing arginine and calcium citrate as specific substrates, diffusible (K2HPO4) and undiffusible (CaCO3) buffer systems, and bromocresol purple as the pH indicator was developed to differentiate among lactic streptococci in pure and mixed cultures. Milk was added as the sole source of carbohydrate (lactose) and to provide growth-stimulating factors. Production of acid from lactose caused developing bacterial colonies to seem yellow. Subsequent arginine utilization by Streptococcus lactis and S. diacetilactis liberated ammonia, resulting in a localized pH shift back toward neutrality and a return of the original purple indicator hue. The effects of production of acid from lactose and ammonia were fixed around individual colonies by the buffering capacity of CaCO3. After 36 hr at 32 C in a candle oats jar, colonies of S. cremoris were yellow, whereas colonies of S. lactis and S. diacetilactis were white. S. diacetilactis, on further incubation, utilized suspended calcium citrate, and, after 6 days, the citrate-degrading colonies exhibited clear zoning against a turbid background, making them easily distinguishable from the colonies of the other two species. The medium proved suitable for quantitative differential enumeration when compared with another widely used general agar medium for lactic streptococci. Images PMID:16349952

  10. Somatic embryogenesis of carrot in hormone-free medium: external pH control over morphogenesis

    NASA Technical Reports Server (NTRS)

    Smith, D. L.; Krikorian, A. D.

    1990-01-01

    Cultures of preglobular stage proembryos (PGSPs) were initiated from mechanically wounded mature zygotic embryos of carrot, Daucus carota, on a hormone-free, semisolid medium. These PGSPs have been maintained and multiplied for extended periods without their progression into later embryo stages on the same hormone-free medium containing 1 mM NH4+ as the sole nitrogen source. Sustained maintenance of cultures comprised exclusively of PGSPs was dependent on medium pH throughout the culture period. Best growth and multiplication of PGSP cultures occurred when the pH of unbuffered, hormone-free medium fell from 4.5 to 4 over a 2-week period or when buffered medium was titrated to pH 4. If the hormone-free medium was buffered to sustain a pH at or above 4.5, PGSPs developed into later embryo stages. Maintenance with continuous multiplication of PGSPs occurred equally well on medium containing NH4+ or NH4+ and NO3-, but growth was poor with NO3- alone. Additional observations on the effects of medium components such as various nitrogen sources and levels, sucrose concentration, semisolid supports, type of buffer, borate concentration, activated charcoal, and initial pH that permit optimum maintenance of the PGSPs or foster their continued developmental progression into mature embryos and plantlets are reported. The influence of the pH of the hormone-free medium as a determinant in maintaining cultures as PGSPs or allowing their continued embryonic development are unequivocally demonstrated by gross morphology, scanning electron microscopy, and histological preparations.

  11. Acetate production from whey lactose using co-immobilized cells of homolactic and homoacetic bacteria in a fibrous-bed bioreactor.

    PubMed

    Huang, Y; Yang, S T

    1998-11-20

    Acetate was produced from whey lactose in batch and fed-batch fermentations using co-immobilized cells of Clostridium formicoaceticum and Lactococcus lactis. The cells were immobilized in a spirally wound fibrous sheet packed in a 0.45-L column reactor, with liquid circulated through a 5-L stirred-tank fermentor. Industrial-grade nitrogen sources, including corn steep liquor, casein hydrolysate, and yeast hydrolysate, were studied as inexpensive nutrient supplements to whey permeate and acid whey. Supplementation with either 2.5% (v/v) corn steep liquor or 1.5 g/L casein hydrolysate was adequate for the cocultured fermentation. The overall acetic acid yield from lactose was 0.9 g/g, and the productivity was 0.25 g/(L h). Both lactate and acetate at high concentrations inhibited the homoacetic fermentation. To overcome these inhibitions, fed-batch fermentations were used to keep lactate concentration low and to adapt cells to high-concentration acetate. The final acetate concentration obtained in the fed-batch fermentation was 75 g/L, which was the highest acetate concentration ever produced by C. formicoaceticum. Even at this high acetate concentration, the overall productivity was 0.18 g/(L h) based on the total medium volume and 1.23 g/(L h) based on the fibrous-bed reactor volume. The cells isolated from the fibrous-bed bioreactor at the end of this study were more tolerant to acetic acid than the original culture used to seed the bioreactor, indicating that adaptation and natural selection of acetate-tolerant strains occurred. This cocultured fermentation process could be used to produce a low-cost acetate deicer from whey permeate and acid whey.

  12. Temperature dependence of ion transport in dilute tetrabutylammonium triflate-acetate solutions and self-diffusion in pure acetate liquids.

    PubMed

    Bopege, Dharshani N; Petrowsky, Matt; Fleshman, Allison M; Frech, Roger; Johnson, Matthew B

    2012-01-12

    Conductivities and static dielectric constants for 0.0055 M tetrabutylammonium trifluoromethanesulfonate in n-butyl acetate, n-pentyl acetate, n-hexyl acetate, n-octyl acetate, and n-decyl acetate have been collected over the temperature range of 0-80 °C. Self-diffusion coefficients and static dielectric constants of pure acetates were obtained over the same temperature range. Both temperature-dependent diffusion coefficients and ionic conductivities of these pure acetates and dilute acetate solutions can be accurately described by the compensated Arrhenius formalism. Activation energies were calculated from compensated Arrhenius plots for both conductivity and diffusion data. Activation energies are higher for conductivity data of 0.0055 M TbaTf-acetates compared to diffusion data of pure acetates. The plot of the exponential prefactor versus the dielectric constant yields a single master curve for both conductivity and diffusion data. These data support the argument that mass and charge transport are thermally activated processes in the acetates, as previously observed in alcohol-based electrolytes. PMID:22145961

  13. Acetate supplementation attenuates lipopolysaccharide-induced neuroinflammation.

    PubMed

    Reisenauer, Chris J; Bhatt, Dhaval P; Mitteness, Dane J; Slanczka, Evan R; Gienger, Heidi M; Watt, John A; Rosenberger, Thad A

    2011-04-01

    Glyceryl triacetate (GTA), a compound effective at increasing circulating and tissue levels of acetate was used to treat rats subjected to a continual 28 day intra-ventricular infusion of bacterial lipopolysaccharide (LPS). This model produces a neuroinflammatory injury characterized by global neuroglial activation and a decrease in choline acetyltransferase immunoreactivity in the basal forebrain. During the LPS infusion, rats were given a daily treatment of either water or GTA at a dose of 6 g/kg by oral gavage. In parallel experiments, free-CoA and acetyl-CoA levels were measured in microwave fixed brains and flash frozen heart, liver, kidney and muscle following a single oral dose of GTA. We found that a single oral dose of GTA significantly increased plasma acetate levels by 15 min and remained elevated for up to 4 h. At 30 min the acetyl-CoA levels in microwave-fixed brain and flash frozen heart and liver were increased at least 2.2-fold. The concentrations of brain acetyl-CoA was significantly increased between 30 and 45 min following treatment and remained elevated for up to 4 h. The concentration of free-CoA in brain was significantly decreased compared to controls at 240 min. Immunohistochemical and morphological analysis demonstrated that a daily treatment with GTA significantly reduced the percentage of reactive glial fibrillary acidic protein-positive astrocytes and activated CD11b-positive microglia by 40-50% in rats subjected to LPS-induced neuroinflammation. Further, in rats subjected to neuroinflammation, GTA significantly increased the number of choline acetyltransferase (ChAT)-positive cells by 40% in the basal forebrain compared to untreated controls. These data suggest that acetate supplementation increases intermediary short chain acetyl-CoA metabolism and that treatment is potentially anti-inflammatory and neuroprotective with regards to attenuating neuroglial activation and increasing ChAT immunoreactivity in this model. PMID:21272004

  14. High-flux cellulose acetate membranes

    SciTech Connect

    Boeddeker, K.W.; Finken, H.; Wenzlaff, A.

    1981-01-01

    Three routes to increase the permeate flux of asymmetric cellulose diacetate membranes of the Loeb-Sourirajan type were investigated: increasing the hydrophilicity of the membranes; increasing their compaction stability, and employing a swelling agent which allows for higher solvent-to-polymer ratio in the casting solution. The effect of casting solution composition on flux and rejection of formamide-modified cellulose acetate membrane is included, illustrating the general capability of this membrane type as function of solvent concentration. Membranes of casting solution composition cellulose diacetate/acetone/formamide 23/52/25 were used as reference membranes in the work. 6 figures. (DP)

  15. The Local Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Ferlet, Roger

    Substantial progress in the field of the Local Interstellar Medium has been largely due to recent launches of space missions, mostly in the UV and X-ray domains, but also to ground-based observations, mainly in high resolution spectroscopy. However, a clear gap seems to remain between the wealth of new data and the theoretical understanding. This paper gives an overview of some observational aspects, with no attempt of completeness or doing justice to all the people involved in the field. As progress rarely evolves in straight paths, we can expect that our present picture of the solar system surroundings is not definitive.

  16. Ruminal buffers: temporal effects on buffering capacity and pH of ruminal fluid from cows fed a high concentrate diet.

    PubMed

    Le Ruyet, P; Tucker, W B

    1992-04-01

    In vitro characteristics of several buffers and alkalinizing agents commonly utilized to reduce ruminal acid load were evaluated. Ruminal fluid was collected from five cows consuming a diet containing concentrate and sorghum silage in a 68:32 ratio (DM basis). This fluid was incubated with either NaHCO3, a natural sodium sesquicarbonate, a multielement buffer or MgO (7.1 g/L of ruminal fluid), or no buffer for 48 h; flasks were removed and analyzed for pH, buffering capacity, and buffer value index every 12 h during the 48-h incubation. The buffer value index accounts simultaneously for alterations in pH and buffering capacity. Compared with the unbuffered control, all buffering compounds increased ruminal fluid buffer value index. However, the buffer value index separated these buffering compounds into two categories. The NaH-CO3 and sodium sesquicarbonate exhibited similar buffer value indexes; both were markedly higher than those for the multielement buffer and MgO. Although NaHCO3 and sodium sesquicarbonate each increased both ruminal fluid pH and buffering capacity sharply, the multielement buffer only increased pH and buffering capacity moderately. The increase in buffer value index for MgO primarily was due to an increase in pH. Both NaHCO3 and sodium sesquicarbonate were fully active within the first 12 h of incubation; activity of multielement buffer and MgO reached a plateau at 24 h. Compared with the multielement buffer and MgO, NaHCO3 and sodium sesquicarbonate should be more beneficial in preventing short-term postprandial increases in ruminal fluid hydrogen ion concentration; because of their slower release rates, the multielement buffer and MgO should help stabilize ruminal acid-base status, but efficacy might be reduced because of passage out of the rumen. PMID:1315810

  17. [Selenazoles. XII. (1) Reaction of 4-(p-tolyl)-selenosemi-carbazides of acetic, benzoic, isonicotinic, nicotinic and picolinic acid with omega-acetophenone].

    PubMed

    Biliński, S; Bielak, L; Chmielewski, J; Marcewicz-Rojewska, B; Musik, I

    1989-01-01

    The cyclization of 4-(p-tolyl)-selenosemicarbazides of acetic, benzoic, isonicotinic, nicotinic and picolinic acids (Ia-e) with omega-bromoacetophenone was investigated in the medium of methanol (Method A) or in methanol in the presence of anhydrous sodium acetate (Method B). Acid hydrolysis of compounds IIf-i and IVa-c, e was studied. Results of UV and IR spectrometric measurements and of the in vitro microbiological studies are presented. In contradistinction to corresponding thiosemicarbazides, the change in N4 nitrogen atom basicity of the parent selenosemicarbazide I (pKa of p-toluidine = 5.1), in comparison to that of 4-phenyl-selenosemicarbazide (pKa of aniline = 4.63), proved to influence the equilibrium of the reaction with omega-bromoacetophenone only in the methanol medium without addition of anhydrous sodium acetate (Method A).

  18. Long-term continuous evolution of acetate resistant Acetobacter aceti.

    PubMed

    Steiner, Peter; Sauer, Uwe

    2003-10-01

    Elevated concentrations of cytotoxic acetate are found in many environmental niches, and few species are relatively resistant to acetate. In particular the high-level acetate resistance of so-called acetic acid bacteria that occurs in industrial settings must be constantly selected for. To investigate the nature of such high-level resistance, we grew the moderately acetate-resistant Acetobacter aceti wild-type and acetate-sensitive Escherichia coli in long-term continuous cultures with increasing acetate concentrations at near neutral pH. While E. coli did not acquire any significant resistance after 125 generations of selection, A. aceti evolved the capability to grow at acetate concentrations exceeding 50 g/L within 240 generations. This phenotype was found to be stable for several generations in the absence of selective pressure, hence must be genetically determined. Intracellular acetate concentrations were significantly lower in evolved A. aceti, when compared to wild-type A. aceti and E. coli, indicating that cytoplasmatic anion accumulation is an important component of acetate toxicity.

  19. Optimizing the availability of a buffered industrial process

    DOEpatents

    Martz, Jr., Harry F.; Hamada, Michael S.; Koehler, Arthur J.; Berg, Eric C.

    2004-08-24

    A computer-implemented process determines optimum configuration parameters for a buffered industrial process. A population size is initialized by randomly selecting a first set of design and operation values associated with subsystems and buffers of the buffered industrial process to form a set of operating parameters for each member of the population. An availability discrete event simulation (ADES) is performed on each member of the population to determine the product-based availability of each member. A new population is formed having members with a second set of design and operation values related to the first set of design and operation values through a genetic algorithm and the product-based availability determined by the ADES. Subsequent population members are then determined by iterating the genetic algorithm with product-based availability determined by ADES to form improved design and operation values from which the configuration parameters are selected for the buffered industrial process.

  20. RESEARCH SHOWS IMPORTANCE OF RIPARIAN BUFFERS FOR AQUATIC HEALTH

    EPA Science Inventory

    Issue: Excess nitrogen from fertilizer, septic tanks, animal feedlots, and runoff from pavement can threaten aquatic ecosystem health. Riparian buffers -- the vegetated region adjacent to streams and wetlands -- are thought to be effective at intercepting and controlling excess ...

  1. On buffer layers as non-reflecting computational boundaries

    NASA Technical Reports Server (NTRS)

    Hayder, M. Ehtesham; Turkel, Eli L.

    1996-01-01

    We examine an absorbing buffer layer technique for use as a non-reflecting boundary condition in the numerical simulation of flows. One such formulation was by Ta'asan and Nark for the linearized Euler equations. They modified the flow inside the buffer zone to artificially make it supersonic in the layer. We examine how this approach can be extended to the nonlinear Euler equations. We consider both a conservative and a non-conservative form modifying the governing equations in the buffer layer. We compare this with the case that the governing equations in the layer are the same as in the interior domain. We test the effectiveness of these buffer layers by a simulation of an excited axisymmetric jet based on a nonlinear compressible Navier-Stokes equations.

  2. 4. EAST FACE. VEGETATIVE SCREENS BUFFER THE BUILDING FROM INDUSTRIAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. EAST FACE. VEGETATIVE SCREENS BUFFER THE BUILDING FROM INDUSTRIAL AREAS TO THE SOUTH OF OARB. - Oakland Army Base, General Purpose Administration Building, Chungking & Algiers Streets, Oakland, Alameda County, CA

  3. Analysis of a unidirectional, symmetric buffer strip laminate with damage

    NASA Technical Reports Server (NTRS)

    Dharani, L. R.; Goree, J. G.

    1984-01-01

    A method for predicting the fracture behavior of hybrid buffer strip laminates is presented in which the classical shear-lag model is used to represent the shear stress distribution between adjacent fibers. The method is demonstrated by applying it to a notched graphite/epoxy laminate, and the results show clearly the manner in which the most efficient combination of buffer strip properties can be selected in order to arrest the crack. The ultimate failure stress of the laminate is plotted vs the buffer strip width. It is shown that in the case of graphite-epoxy and S-glass epoxy laminates, the optimum buffer strip spacing to width ratio should be about four to one.

  4. Buffer layers for high-Tc thin films on sapphire

    NASA Technical Reports Server (NTRS)

    Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

    1992-01-01

    Buffer layers of various oxides including CeO2 and yttrium-stabilized zirconia (YSZ) have been deposited on R-plane sapphire. The orientation and crystallinity of the layers were optimized to promote epitaxial growth of YBa2Cu3O(7-delta) (YBCO) thin films. An ion beam channeling minimum yield of about 3 percent was obtained in the CeO2 layer on sapphire, indicating excellent crystallinity of the buffer layer. Among the buffer materials used, CeO2 was found to be the best one for YBCO thin films on R-plane sapphire. High Tc and Jc were obtained in YBCO thin films on sapphire with buffer layers. Surface resistances of the YBCO films were about 4 mOmega at 77 K and 25 GHz.

  5. Religion a Buffer Against Suicide for Women, Study Suggests

    MedlinePlus

    ... html Religion a Buffer Against Suicide for Women, Study Suggests Going to services at least once a ... suicide than those who don't, a new study suggests. U.S. researchers reviewed data on nearly 90, ...

  6. DENSE MEDIUM CYCLONE OPTIMIZATON

    SciTech Connect

    Gerald H. Luttrell; Chris J. Barbee; Peter J. Bethell; Chris J. Wood

    2005-06-30

    Dense medium cyclones (DMCs) are known to be efficient, high-tonnage devices suitable for upgrading particles in the 50 to 0.5 mm size range. This versatile separator, which uses centrifugal forces to enhance the separation of fine particles that cannot be upgraded in static dense medium separators, can be found in most modern coal plants and in a variety of mineral plants treating iron ore, dolomite, diamonds, potash and lead-zinc ores. Due to the high tonnage, a small increase in DMC efficiency can have a large impact on plant profitability. Unfortunately, the knowledge base required to properly design and operate DMCs has been seriously eroded during the past several decades. In an attempt to correct this problem, a set of engineering tools have been developed to allow producers to improve the efficiency of their DMC circuits. These tools include (1) low-cost density tracers that can be used by plant operators to rapidly assess DMC performance, (2) mathematical process models that can be used to predict the influence of changes in operating and design variables on DMC performance, and (3) an expert advisor system that provides plant operators with a user-friendly interface for evaluating, optimizing and trouble-shooting DMC circuits. The field data required to develop these tools was collected by conducting detailed sampling and evaluation programs at several industrial plant sites. These data were used to demonstrate the technical, economic and environmental benefits that can be realized through the application of these engineering tools.

  7. Rotational relaxation of molecular ions in a buffer gas

    NASA Astrophysics Data System (ADS)

    Pérez-Ríos, Jesús; Robicheaux, F.

    2016-09-01

    The scattering properties regarding the rotational degrees of freedom of a molecular ion in the presence of a buffer gas of helium are investigated. This study is undertaken within the framework of the infinite-order sudden approximation for rotational transitions, which is shown to be applicable to a large variety of molecular ions in a buffer gas of helium at fairly low temperatures. The results derived from the present approach have potential applications in cold chemistry and molecular quantum logic spectroscopy.

  8. Carbon dioxide in the ocean surface: The homogeneous buffer factor

    USGS Publications Warehouse

    Sundquist, E.T.; Plummer, L.N.; Wigley, T.M.L.

    1979-01-01

    The amount of carbon dioxide that can be dissolved in surface seawater depends at least partially on the homogeneous buffer factor, which is a mathematical function of the chemical equilibrium conditions among the various dissolved inorganic species. Because these equilibria are well known, the homogeneous buffer factor is well known. Natural spatial variations depend very systematically on sea surface temperatures, and do not contribute significantly to uncertainties in the present or future carbon dioxide budget. Copyright ?? 1979 AAAS.

  9. Fracture of composite plates containing periodic buffer strips

    NASA Technical Reports Server (NTRS)

    Erdogan, F.; Bakioglu, M.

    1974-01-01

    Fracture of a composite plate which consists of perfectly bonded parallel load carrying laminates and buffer strips is considered. Fatigue cracks appear and spread in main laminates or in buffer strips or in both perpendicular to the interfaces. The external load is applied to the plate parallel to the strips and away from the crack region. The problem is solved for fully imbedded cracks and for broken laminates or strips. Corresponding stress intensity factors are calculated.

  10. Riparian forest buffers in the Chesapeake Bay watershed. Fact sheet

    SciTech Connect

    1995-07-01

    The concept behind a riparian buffer is to put the natural benefits and functions of riparian areas to work in nonpoint pollution control. These linear strips of forest can serve as the last line of defense from the activities we undertake in managing the land, such as agriculture, grazing and urban development. Unlike most best management practices, the high value of forests to wildlife and fish, helps buffers accomplish habitat benefits at the same time they improve their water quality.

  11. Immunotoxicity of trenbolone acetate in Japanese quail

    USGS Publications Warehouse

    Quinn, M.J.; McKernan, M.; Lavoie, E.T.; Ottinger, M.A.

    2007-01-01

    Trenbolone acetate is a synthetic androgen that is currently used as a growth promoter in many meat-exporting countries. Despite industry laboratories classifying trenbolone as nonteratogenic, data showed that embryonic exposure to this androgenic chemical altered development of the immune system in Japanese quail. Trenbolone is lipophilic, persistent, and released into the environment in manure used as soil fertilizer. This is the first study to date to assess this chemical's immunotoxic effects in an avian species. A one-time injection of trenbolone into yolks was administered to mimic maternal deposition, and subsequent effects on the development and function of the immune system were determined in chicks and adults. Development of the bursa of Fabricius, an organ responsible for development of the humoral arm of the immune system, was disrupted, as indicated by lower masse, and smaller and fewer follicles at day 1 of hatch. Morphological differences in the bursas persisted in adults, although no differences in either two measures of immune function were observed. Total numbers of circulating leukocytes were reduced and heterophil-lymphocyte ratios were elevated in chicks but not adults. This study shows that trenbolone acetate is teratogenic and immunotoxic in Japanese quail, and provides evidence that the quail immune system may be fairly resilient to embryonic endocrine-disrupting chemical-induced alterations following no further exposure posthatch.

  12. D-buffer: irregular image data storage made practical

    NASA Astrophysics Data System (ADS)

    Lipowski, J. K.

    2013-03-01

    Modern hardware accelerated graphics pipelines are designed to operate on data in a so called streaming model. To process the data in this model one needs to impose some restrictions on input and output argument's (most frequently represented by a two-dimensional frame buffer) memory structure. The output data regularity is obvious when we consider rasterizing hardware architecture, which draws 3D polygons using depth buffer to resolve the visible surface problem. But recently the user's needs surpass those restrictions with increasing frequency. In this work we formulate and present new methods of irregular frame buffer storage and ordering. The so called deque buffer (or D-buffer) allows us to decrease the amount of memory used for storage as well as the memory latency cost by using pixel data ordering. Our findings are confirmed by experimental results that measure the processing time, which is up to four times shorter, when compared with previous work by other authors. We also include a detailed description of algorithms used for D-buffer construction on the last three consumer-grade graphics hardware architectures, as a guide for other researchers and a development aid for practitioners. The only theoretical requirement imposed by our method is the use of memory model with linear address space.

  13. Genetic dissection of acetic acid tolerance in Saccharomyces cerevisiae.

    PubMed

    Geng, Peng; Xiao, Yin; Hu, Yun; Sun, Haiye; Xue, Wei; Zhang, Liang; Shi, Gui-Yang

    2016-09-01

    Dissection of the hereditary architecture underlying Saccharomyces cerevisiae tolerance to acetic acid is essential for ethanol fermentation. In this work, a genomics approach was used to dissect hereditary variations in acetic acid tolerance between two phenotypically different strains. A total of 160 segregants derived from these two strains were obtained. Phenotypic analysis indicated that the acetic acid tolerance displayed a normal distribution in these segregants, and suggested that the acetic acid tolerant traits were controlled by multiple quantitative trait loci (QTLs). Thus, 220 SSR markers covering the whole genome were used to detect QTLs of acetic acid tolerant traits. As a result, three QTLs were located on chromosomes 9, 12, and 16, respectively, which explained 38.8-65.9 % of the range of phenotypic variation. Furthermore, twelve genes of the candidates fell into the three QTL regions by integrating the QTL analysis with candidates of acetic acid tolerant genes. These results provided a novel avenue to obtain more robust strains.

  14. 1'-Acetoxychavicol acetate as an inhibitor of phagocytosis of macrophages.

    PubMed

    Watanabe, N; Kataoka, T; Tajika, T; Uramoto, M; Magae, J; Nagai, K

    1995-08-01

    We screened extracts of edible plants for inhibitors of phagocytosis by peritoneal exudate macrophages. 1'-Acetoxychavicol acetate was isolated from the ethyl acetate extract of Languas galanga, and this compound strongly inhibited phagocytosis at an IC50 value of 1.2 microM with negligible effects on pinocytosis and cell viability. Target(s) of 1'-acetoxychavicol acetate was suggested to be downstream of the signal transduction pathway that is mediated by protein kinase C.

  15. Epitaxial growth and thermal dynamics of CeO II buffer layer on textured Ni-W substrates for YBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Pan, C. Y.; Cai, C. B.; Ying, L. L.; Lu, Y. M.; Liu, Z. Y.; Gao, B.; Liu, J. L.

    2008-02-01

    In present study, the biaxially textured CeO II buffer layers on Ni-W substrates have been prepared by chemical solution deposition (CSD) with cerium acetate as the starting precursor, mixed with solvents of Propionic acid, Isopropanol and Acetylacetone. Typical XRD θ-2θ scans and the pole figure display well out-of-plane and in-plane textures of CeO II films. SEM and AFM results suggest that the buffer layer have uniform and smooth surface. Meanwhile, the effects of heating rate on CeO II formation starting from the precursor solution have been studied using differential thermal analysis (DTA). And the further analysis is given by XRD results for precursor xrogel at the corresponding temperature. Detailed high temperature optical microscope (HTOM) photographs investigate the surface characteristics evolved with temperature.

  16. Grape contribution to wine aroma: production of hexyl acetate, octyl acetate, and benzyl acetate during yeast fermentation is dependent upon precursors in the must.

    PubMed

    Dennis, Eric G; Keyzers, Robert A; Kalua, Curtis M; Maffei, Suzanne M; Nicholson, Emily L; Boss, Paul K

    2012-03-14

    Wine is a complex consumer product produced predominately by the action of yeast upon grape juice musts. Model must systems have proven ideal for studies of the effects of fermentation conditions on the production of certain wine volatiles. To identify grape-derived precursors to acetate esters, model fermentation systems were developed by spiking precursors into model must at different concentrations. Solid-phase microextraction-gas chromatgraphy mass spectrometry analysis of the fermented wines showed that a variety of grape-derived aliphatic alcohols and aldehydes are precursors to acetate esters. The C6 compounds hexan-1-ol, hexenal, (E)-2-hexen-1-ol, and (E)-2-hexenal are all precursors to hexyl acetate, and octanol and benzyl alcohol are precursors to octyl acetate and benzyl acetate, respectively. In these cases, the postfermentation concentration of an acetate ester increased proportionally with the prefermentation concentration of the respective precursor in the model must. Determining viticultural or winemaking methods to alter the prefermentation concentration of precursor compounds or change the precursor-to-acetate ester ratio will have implications upon the final flavor and aroma of wines. PMID:22332880

  17. Inactivation of viruses using novel protein A wash buffers.

    PubMed

    Bolton, Glen R; Selvitelli, Keith R; Iliescu, Ionela; Cecchini, Douglas J

    2015-01-01

    Low pH viral inactivation is typically performed in the eluate pool following the protein A capture step during the manufacturing of monoclonal antibodies and Fc-fusion proteins. However, exposure to low pH has the potential to alter protein quality. To avoid these difficulties, novel wash buffers capable of inactivating viruses while antibodies or Fc-fusion proteins were bound to protein A or mixed mode resins were developed. By equilibrating the column in high salt buffer (2 M ammonium sulfate or 3 M sodium chloride) after loading, the hydrophobic interactions between antibodies and protein A ligands were increased enough to prevent elution at pH 3. The ammonium sulfate was also found to cause binding of an antibody to a mixed mode cation exchange and a mixed mode anion exchange resin at pH values that caused elution in conventional cation and anion exchange resins (pH 3.5 for Capto Adhere and pH 8.0 for Capto MMC), indicating that retention was due to enhanced hydrophobic interactions. The potential of the 2 M ammonium sulfate pH 3 buffer, a 1 M arginine buffer, and a buffer containing the detergent LDAO to inactivate XMuLV virus when used as protein A wash buffers with a 1 hour contact time were studied. The high salt and detergent containing wash buffers provided about five logs of removal, determined using PCR, and complete combined removal and inactivation (> 6 logs), determined by measuring infectivity. The novel protein A washes could provide more rapid, automated viral inactivation steps with lower pool conductivities.

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

    SciTech Connect

    Paranthaman, Mariappan Parans

    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.

  19. Assessing multiregion avian benefits from strategically targeted agricultural buffers.

    PubMed

    Evans, Kristine O; Burger, L Wes; Riffell, Sam; Smith, Mark D

    2014-08-01

    Mounting evidence of wildlife population gains from targeted conservation practices has prompted the need to develop and evaluate practices that are integrated into production agriculture systems and targeted toward specific habitat objectives. However, effectiveness of targeted conservation actions across broader landscapes is poorly understood. We evaluated multiregion, multispecies avian densities on row-crop fields with native grass field margins (i.e., buffers) as part of the first U.S. agricultural conservation practice designed to support habitat and population recovery objectives of a national wildlife conservation initiative. We coordinated breeding season point transect surveys for 6 grassland bird species on 1151 row-crop fields with and without native grass buffers (9-37 m) in 14 U.S. states (10 ecoregions) from 2006 to 2011. In most regions, breeding season densities of 5 of 6 targeted bird species were greater in the 500-m surrounding survey points centered on fields with native grass buffers than in landscapes without buffers. Relative effect sizes were greatest for Northern Bobwhite (Colinus virginianus), Dickcissel (Spiza americana), and Field Sparrow (Spizella pusilla) in the Mississippi Alluvial Valley and Eastern Tallgrass Prairie regions. Other species (e.g., Eastern Meadowlark [Sturnella magna], Grasshopper Sparrow [Ammodramus savannarum]) exhibited inconsistent relative effect sizes. Bird densities on fields with and without buffers were greatest in the Central Mixed-grass Prairie region. Our results suggest that strategic use of conservation buffers in regions with the greatest potential for relative density increases in target species will elicit greater range-wide population response than diffuse, uninformed, and broadly distributed implementation of buffers. We recommend integrating multiple conservation practices in broader agricultural landscapes to maximize conservation effectiveness for a larger suite of species.

  20. Mapping Soil pH Buffering Capacity of Selected Fields

    NASA Technical Reports Server (NTRS)

    Weaver, A. R.; Kissel, D. E.; Chen, F.; West, L. T.; Adkins, W.; Rickman, D.; Luvall, J. C.

    2003-01-01

    Soil pH buffering capacity, since it varies spatially within crop production fields, may be used to define sampling zones to assess lime requirement, or for modeling changes in soil pH when acid forming fertilizers or manures are added to a field. Our objective was to develop a procedure to map this soil property. One hundred thirty six soil samples (0 to 15 cm depth) from three Georgia Coastal Plain fields were titrated with calcium hydroxide to characterize differences in pH buffering capacity of the soils. Since the relationship between soil pH and added calcium hydroxide was approximately linear for all samples up to pH 6.5, the slope values of these linear relationships for all soils were regressed on the organic C and clay contents of the 136 soil samples using multiple linear regression. The equation that fit the data best was b (slope of pH vs. lime added) = 0.00029 - 0.00003 * % clay + 0.00135 * % O/C, r(exp 2) = 0.68. This equation was applied within geographic information system (GIS) software to create maps of soil pH buffering capacity for the three fields. When the mapped values of the pH buffering capacity were compared with measured values for a total of 18 locations in the three fields, there was good general agreement. A regression of directly measured pH buffering capacities on mapped pH buffering capacities at the field locations for these samples gave an r(exp 2) of 0.88 with a slope of 1.04 for a group of soils that varied approximately tenfold in their pH buffering capacities.