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1

Simultaneous determination of uric acid and ascorbic acid using glassy carbon electrodes in acetate buffer solution  

Microsoft Academic Search

The present work reports the simultaneous determination of uric acid (UA) and ascorbic acid (AA) in 0.2M, pH 4.0, acetate buffer solution using glassy carbon (GC) electrode by square wave voltammetry. Selective detection of UA in the presence of 200-fold excess of AA is achieved at the GC electrode in acetate buffer solution. The GC electrode separates the voltammetric signal

S. Abraham John

2005-01-01

2

Buffer Index and Buffer Capacity for a Simple Buffer Solution  

NASA Astrophysics Data System (ADS)

Many papers that present the buffering effect of the simple buffer solution consider the notion of buffer index and buffer capacity as being equivalent. Moreover, IUPAC defies them as the same thing. According to the definition of the authors who have introduced these two units, the paper shows that there is a large difference between them. The buffer index can be defined as the differential ratio of the increase in the amount of strong acid or strong base added, to pH variation. The buffer capacity is numerically expressed to be equal with the minimum concentration of strong acid or strong base which causes the variation of buffer's pH with one unit. The field of application of both notions is different: the buffer capacity is used in the quantitative chemical analysis and the buffer index in studying biological systems.

Chiriac, Veronica; Balea, Gabriel

1997-08-01

3

Physico-chemical studies of micelle formation on sepia cartilage collagen solutions in acetate buffer and its interaction with ionic and nonionic micelles. Hydrodynamic and thermodynamic studies.  

PubMed

Sepia cartilage collagen (pepsin-extracted) in acetate buffer (pH = 2.98) forms micelles at a particular concentration below which they do not normally form. The critical micelle concentration (cmc) of the collagen was determined in buffer as well as in SDS, cetyltrimethylammonium bromide (CTAB) and Tween-80 micellar environments at different temperatures. Mutual interaction of collagen micelles with the ionic and nonionic micelles through the formation of the mixed micelle concept has also been found. The cmc of collagen decreased in the presence of SDS and Tween-80 micelles whereas it increased in the presence of CTAB micelles. This clearly suggests that the micelle formation of collagen is facilitated by the presence of SDS and Tween-80 and hindered by CTAB micelles. The various thermodynamic parameters were estimated from viscosity measurements and the transfer of collagen into the micelles of various surfactants and the reverse phenomenon was analyzed. This analysis has also been modelled conceptually as a different phase and the results have supported the above phenomenon. Our thermodynamic results are also able to predict the exact denaturation temperature as well as the structural order of water in the collagen in various environments. The hydrated volumes, Vh, of collagen in the above environments and intrinsic viscosity were also calculated. The low intrinsic viscosity, [eta], of collagen in an SDS environment compared to buffer and other surfactant environments suggested more workable systems in cosmetic and dermatological skin care preparations. The one and two-hydrogen-bonded models of this collagen in various environments have been analyzed. The calculated thermodynamic parameters varied with the concentration of collagen. The change of thermodynamic parameters from coil-coil to random-coil conformation upon denaturation of collagen were calculated from the amount of proline and hydroxyproline residues and compared with viscometric results. Thermodynamic results suggest that the stability of the collagen in the additive environments is in the following order: SDS greater than Tween-80 greater than buffer greater than CTAB. PMID:3691510

Mandal, A B; Ramesh, D V; Dhar, S C

1987-12-15

4

Electrodialysis operation with buffer solution  

DOEpatents

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

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

2009-12-15

5

The Effects of Acetate Buffer Concentration on Lysozyme Solubility  

NASA Technical Reports Server (NTRS)

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.

Forsythe, Elizabeth L.; Pusey, Marc L.

1996-01-01

6

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

PubMed

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

Rose, C; Mandal, A B

1996-02-01

7

Reactivity of some sugars and sugar phosphates towards gold(III) in sodium acetate–acetic acid buffer medium  

Microsoft Academic Search

The kinetics of the oxidation of some aldoses and aldose phosphates have been studied spectrophotometrically in sodium acetate–acetic acid buffer medium at different temperatures. The reactions are first order with respect to [Au(III)] and [substrate]. Both H+ and Cl? ions retard the reaction. The reactions appear to involve different gold(III) species, viz. AuCl4?, AuCl3(OH2) and AuCl3(OH)?. The results are interpreted

Kalyan Kali Sen Gupta; Biswajit Pal; Bilkis Ara Begum

2001-01-01

8

Phosphate Dialytic Removal: Enhancement of Phosphate Cellular Clearance by Biofiltration (with Acetate-Free Buffer Dialysate)  

Microsoft Academic Search

Phosphate dialytic removal (PDR) depends in part on the type (acetate or bicarbonate) and the concentration of the buffer dialysate. Plasma phosphate reduction or PDR during a dialysis treatment is the algebraic sum, of phosphate cellular flux (removal or captation) and of phosphate tissular precipitation. High bicarbonate levels induce an intracellular shift of phosphate, thus not available for dialytic removal.

M. Fischbach; G. Hamel; U. Simeoni; J. Geisert

1992-01-01

9

Reactivity of some sugars and sugar phosphates towards gold(III) in sodium acetate-acetic acid buffer medium.  

PubMed

The kinetics of the oxidation of some aldoses and aldose phosphates have been studied spectrophotometrically in sodium acetate-acetic acid buffer medium at different temperatures. The reactions are first order with respect to [Au(III)] and [substrate]. Both H+ and Cl- ions retard the reaction. The reactions appear to involve different gold(III) species, viz. AuCl4-, AuCl3(OH2) and AuCl3(OH)- . The results are interpreted in terms of the probable intermediate formation of free radicals and Au(II). Aldoses react with gold(III) in the order: triose > tetrose > pentose > hexose. The sugar phosphates react with gold(III) at a faster rate than the parent sugars except glucose-1-phosphate, which reacts at slower rates than glucose. A tentative reaction mechanism leading to the formation of products has been suggested. PMID:11217954

Sen Gupta, K K; Pal, B; Begum, B A

2001-01-15

10

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

PubMed

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

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

11

76 FR 32366 - Determination That ORLAAM (Levomethadyl Acetate Hydrochloride) Oral Solution, 10 Milligrams...  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and...Levomethadyl Acetate Hydrochloride) Oral Solution, 10 Milligrams/Milliliter...acetate hydrochloride (HCl)) oral solution, 10 milligrams (mg...for levomethadyl acetate HCl oral solution, 10 mg/mL, if...

2011-06-06

12

CHEMICAL SOLUTION DEPOSITION BASED OXIDE BUFFERS AND YBCO COATED CONDUCTORS  

SciTech Connect

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.

Paranthaman, Mariappan Parans [ORNL

2011-01-01

13

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

PubMed

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

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

2014-06-25

14

Pyrite oxidation in carbonate-buffered solution: 1. Experimental kinetics  

Microsoft Academic Search

The kinetic behavior of pyrite oxidation in carbonate-buffered solution was investigated in the laboratory. Oxygen concentration, surface area and temperature were varied while pH values were limited to the range of 6.7-8.5. The rate experiments were performed on crushed and sieved size-fractions of pyrite that were carefully cleaned and mixed with similar-size silica sand. Oxidation occurred in a moisture-suction device

R. V. Nicholson; R. W. Gillham; E. J. Reardon

1988-01-01

15

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

SciTech Connect

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.

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

1996-12-31

16

Kinetics and mechanism of cymoxanil degradation in buffer solutions.  

PubMed

The kinetics and mechanism(s) of the hydrolytic degradation of a compound are needed to evaluate a compound's abiotic degradation in the environment. In this paper, the hydrolysis of cymoxanil [2-cyano-N-[(ethylamino)carbonyl]-2-(methoxyimino) acetamide] was investigated in dark sterile aqueous solutions under a variety of pH conditions (pH 2.8-9.2) and temperatures (15-50 degrees C). Hydrolysis of cymoxanil was described by first-order kinetics, which was dependent on pH and temperature. Cymoxanil degraded rapidly at pH 9 (half-life = 31 min) and relatively slowly at pH 2.8 (half-life = 722 days). The effect of temperature on the rate of cymoxanil degradation was characterized using the Arrhenius equation with an estimated energy of activation of 117.1 kJ mol(-)(1). An increase in temperature of 10 degrees C resulted in a decrease in half-life by a factor of approximately 5. Three competing degradation pathways are proposed for the hydrolysis of cymoxanil, with two of the pathways accounting for approximately 90% of cymoxanil degradation. These two pathways involved either initial cyclization to 1-ethyldihydro-6-imino-2,3,5(3H)-pyrimidinetrione-5-(O-methyloxime) (1, Figure 1) or direct cleavage of the C-1 amide bond to form cyano(methoxyimino) acetic acid (7). The third pathway of degradation involved initial cyclization to 3-ethyl-4-(methoxyimino)-2,5-dioxo-4-imidazolidinecarbonitrile (8), which rapidly degrades into 1-ethyl-5-(methoxyimino)-2,4-imidazoline-2,4-dione (9). All three pathways eventually lead to the formation of the polar metabolite oxalic acid. PMID:14709020

Morrica, Patrizia; Trabue, Steven; Anderson, Jeffrey J; Lawler, Sonya; Seccia, Serenella; Fidente, Paola; Swain, R Scott; Mattson, S Lynne

2004-01-14

17

The Determination of the pH of Standard Buffer Solution: A Laboratory Experiment.  

ERIC Educational Resources Information Center

Describes an experiment which shows: (1) how measurements of the reaction electromotive force for the cell (Pt/glass/NaCl(aq,m),buffer/AgCl/Ag/Pt) can be utilized in determining the absolute pH of the buffer; and (2) the demonstration of the use of the Debye-Huckel model of an electrolyte solution in solving an important electrochemical problem.…

Harris, K. R.

1985-01-01

18

Zinc deficiency in wheat genotypes grown in conventional and chelator-buffered nutrient solutions  

Microsoft Academic Search

Chelator-buffered nutrient solutions have been used extensively in studying plant–micronutrient relationships, but the effects of the chelator on plants are poorly understood. This study compared responses to Zn deficiency of two wheat genotypes (Triticum aestivum, cv. Aroona, and T. turgidum L. conv. durum, cv. Durati) grown in conventional and chelator-buffered nutrient solutions. With the same low activity of Zn2+ in

Z. Rengel

1999-01-01

19

Corrosion rate of magnesium and its alloys in buffered chloride solutions  

Microsoft Academic Search

The effect of the buffer capacity of test solution on the corrosion rate of cast pure (>99.95 mass%) and high-purity (>99.9999 mass%) magnesium, and AZ31 and AZ91E has been studied. Their corrosion rates were measured gravimetrically in a pH 6.5 and a pH 9 borate buffer including chloride ions, and in a conventional chloride solution. Except for the AZ91E in

H Inoue; K Sugahara; A Yamamoto; H Tsubakino

2002-01-01

20

Uptake of zinc from chelate-buffered nutrient solutions by wheat genotypes differing in zinc efficiency  

Microsoft Academic Search

Zinc-efficient Triticum aestivum (cv. Warigal) and Zn-inefficient Triticum turgidum conv. durum (cv. Durati) were grown in chelate-buffe red, complete nutrient solutions providing either deficient or suffi- cient Zn supply. When transferred to fresh chelate- buffered nutrient solutions containing a wide range of Zn supplies (0-1.28\\/rniol m\\

Zdenko Rengel; Robin D. Graham

1996-01-01

21

Pyrite oxidation in carbonate-buffered solution: 2. Rate control by oxide coatings  

Microsoft Academic Search

The kinetic behavior of pyrite oxidation in the laboratory was studied over a period of about 10,000 hours in reactors through which a carbonate-buffered solution and air (20% Oâ) flowed continuously. Three grain size fractions were monitored. The concentration of sulfate and the mass of the effluent solution were measured periodically to calculate oxidation rates. The results indicate that the

R. V. Nicholson; R. W. Gillham; E. J. Reardon

1990-01-01

22

Multi-ion sensing of buffer solutions using terahertz chemical microscopy  

NASA Astrophysics Data System (ADS)

Terahertz chemical microscopy (TCM) has been proposed and developed to visualize electric potential and/or chemical changes in water solutions. To simultaneously detect two types of ions mixed in buffer solutions, five membranes for sodium ions and four membranes for potassium ions were integrated on a sensing plate, and the selectivity to each ion was evaluated. The results suggest that TCM can be used for multi-ion sensing in mixed solutions.

Akimune, Kosuke; Okawa, Yuki; Sakai, Kenji; Kiwa, Toshihiko; Tsukada, Keiji

2014-12-01

23

Thick lanthanum zirconate buffer layers from water-based precursor solutions on Ni-5%W substrates  

SciTech Connect

In this work, water-based precursor solutions suitable for dip-coating of thick La{sub 2}Zr{sub 2}O{sub 7} (LZO) buffer layers for coated conductors on Ni-5%W substrates were developed. The solutions were prepared based on chelate chemistry using water as the main solvent. The effect of polymer addition on the maximum crack-free thickness of the deposited films was investigated. This novel solution preparation method revealed the possibility to grow single, crack-free layers with thicknesses ranging 100-280 nm with good crystallinity and an in-plane grain misalignment with average FWHM of 6.55{sup o}. TEM studies illustrated the presence of nanovoids, typical for CSD-LZO films annealed under Ar-5%H{sub 2} gas flow. The appropriate buffer layer action of the film in preventing the Ni diffusion was studied using XPS. It was found that the Ni diffusion was restricted to the first 30 nm of a 140 nm thick film. The surface texture of the film was improved using a seed layer. - Graphical abstract: Thick LZO buffer layers from water-based precursor solutions were synthesized and their crystallinity, microstructure and buffer layer action were studied. The buffer layer action of the LZO layer was substantial to restrict the Ni penetration within 30 nm of a 140 nm thick film. Highlights: > LZO buffer layers with high thicknesses for use in coated conductors were prepared. > Prepared from water-based solutions. > Polymeric PVP increases the crack-free critical thickness of thick films. > Thick films showed good barrier action against Ni penetration. > Seed layers promote epitaxial growth of thick layers.

Narayanan, Vyshnavi; Lommens, Petra; De Buysser, Klaartje [SCRIPTS, Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, B-9000 Gent (Belgium); Huehne, Ruben [IFW Dresden, Institute for Metallic Materials, Helmholtzstrasse 20, 01069 Dresden (Germany); Van Driessche, Isabel, E-mail: Isabel.Vandriessche@UGent.Be [SCRIPTS, Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, B-9000 Gent (Belgium)

2011-11-15

24

Development of a boron buffered solution culture system for controlled studies of plant boron nutrition  

Microsoft Academic Search

Chelated-buffered nutrient solutions are used for studies on micronutrient metals but so far no equivalent system exists for boron nutrition studies: the present investigation was initiated with that intention. From a literature review, it was noted that a range of substances form chelates with boron including polyhydric alcohols, sugars and phenolic compounds. However, none apart from hydrofluoric acid formed chelates

A. Asad; R. W. Bell; L. Huang

1997-01-01

25

OPTIMIZING PHOSPHORUS AND ZINC CONCENTRATIONS IN HYDROPONIC CHELATOR-BUFFERED NUTRIENT SOLUTION FOR RUSSET BURBANK POTATO  

Microsoft Academic Search

High rates of phosphorus (P) fertilizer for potato production have potentially negative environmental and nutritional consequences, including antagonistic interactions with micronutrients. Variable P or zinc (Zn) treatments were evaluated in chelator-buffered solutions to identify deficient, sufficient, and excess concentrations for Russet Burbank potato. Visual observations, dry matter, and nutrient concentrations confirmed 0.1 and 2 ?M as deficient, 6 to 54

Steven A. Barben; Bryan G. Hopkins; Von D. Jolley; Bruce L. Webb; Brandt A. Nichols

2010-01-01

26

Fluoroalcohols as novel buffer components for basic buffer solutions for liquid chromatography electrospray ionization mass spectrometry: Retention mechanisms  

Microsoft Academic Search

Two fluoroalcohols – 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol (HFTB) – were evaluated as volatile buffer acids in basic mobile phases for LC–ESI-MS determination of acidic and basic compounds. HFIP and HFTB as acidic buffer components offer interesting possibilities to adjust retention behavior of different analytes and expand the currently rather limited range of ESI-compatible buffer systems for basic mobile phases. Comparing

Karin Kipper; Koit Herodes; Ivo Leito

2011-01-01

27

Relaxation to equilibrium following photoacid dissociation in mineral acids and buffer solutions  

NASA Astrophysics Data System (ADS)

The relaxation to the dissociation equilibrium of a weak acid undergoing a transient pKa change in the presence of a strong mineral acid has been the subject of considerable interest both experimentally and theoretically. Here we compare this process with the analogue event taking place in a buffer solution of a weak carboxylic acid. The comparison has been performed in identical pH and ionic strength conditions and at a sufficiently short timescale where the buffer can only affect the weak acid relaxation by proton scavenging. Although the two relaxation processes have been found to differ in their temporal behaviour, they have both resulted in identical equilibrium amplitudes of the photoacid. This observation reassures the well-known chemical wisdom that pKa values measured in buffer solutions do not depend on the specific chemical reactivity of the buffer. We analyse the essentially many-body relaxation problem in terms of a re-normalized geminate recombination reaction which persists over longer times than the exponential relaxation to equilibrium of homogenously distributed populations of the reactants.

Pines, D.; Nibbering, E. T. J.; Pines, E.

2007-02-01

28

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

SciTech Connect

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

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

2007-07-26

29

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

PubMed

Abstract 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. PMID:24261406

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

2015-02-01

30

Critical zinc[sup +2] activities for sour orange determined with chelator-buffered nutrient solutions  

Microsoft Academic Search

Chelator-buffered nutrient solutions were used to study the effect of different levels of Zn activity in the rhizosphere on growth and nutritive responses of various tissues of sour orange seedlings. The seedlings were grown for 3 months in a growth chamber in a hydroponic culture containing from 5 to 69 [mu]m and 5 to 101 [mu]m total Zn in Expts.

D. Swietlik; L. Zhang

1994-01-01

31

Study on fisetin–aluminium(III) interaction in aqueous buffered solutions by spectroscopy and molecular modeling  

Microsoft Academic Search

Spectroscopic (UV\\/visible and IR) and theoretical studies were used to assess relevant interaction of fisetin, a tetrahydroxylated flavone molecule, and trivalent aluminium in a wide range of buffered aqueous solutions. The chelation sites, stoichiometry, stability and the dependence of the complexes structures on pH and aluminium\\/fisetin mole ratios were defined. Obtained results implicated successive formation of two complexes with aluminium(III)–fisetin

Jasmina M. Dimitri? Markovi?; Zoran S. Markovi?; Dragan S. Veselinovi?; Jugoslav B. Krsti?; Jasmina D. Predojevi? Simovi?

2009-01-01

32

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

PubMed

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

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

2006-06-01

33

In situ Raman spectroscopy investigation of bioactive glass reactivity: Simulated body fluid solution vs TRIS-buffered solution  

Microsoft Academic Search

In the present contribution, the innovative in situ Raman micro-spectroscopy was applied to investigate the in vitro reactivity of various bioactive glasses. All the investigated glasses belonged to the Na2O\\\\K2O–CaO–P2O5–SiO2 system, but contained sensibly different percentages of network modifiers. The glasses were immersed for increasing times, up to 96h, in simulated body fluid (SBF) and in tris-buffered (TRIS) solution. In

D. Bellucci; G. Bolelli; V. Cannillo; A. Cattini; A. Sola

2011-01-01

34

Performance of cellulose acetate butyrate membranes in hyperfiltration of sodium chloride and urea feed solution  

NASA Technical Reports Server (NTRS)

Cellulose acetate butyrate (CAB) membranes are shown to give high salt and urea rejection with water flux of about 3 gallons/sq ft per day at 600 psig. Membranes prepared from a formulation containing glyoxal show a significant increase in flux and decrease in salt and urea rejection with drying time. Zero drying time gives maximum urea and salt rejection and is therefore most suitable for hyperfiltration of sodium chloride and urea feed solution.

Wydeven, T.; Leban, M.

1973-01-01

35

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

NASA Astrophysics Data System (ADS)

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

Siddique, Jamal Akhter; Naqvi, Saeeda

2012-01-01

36

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

37

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

SciTech Connect

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

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

2008-09-24

38

Imaging microtubules in buffer solution using tapping mode atomic force microscopy  

NASA Astrophysics Data System (ADS)

Taxol stabilized microtubules were imaged in their native state in buffer solution without any fixation by an atomic force microscope (AFM) operated in tapping mode in liquids. Glass cover slips were derivatized with a positively charged silane to adsorb the filaments. The adsorbed microtubules could be imaged stably without any visible damage for hours. In cases where a microtubule crossed above another one, it often broke to follow the curvature of the underlying one. Longitudinal structures with a spacing of about 8 nm could be resolved suggesting they are protofilaments.

Fritz, Monika; Radmacher, Manfred; Allersma, Miriam W.; Cleveland, Jason P.; Stewart, Russell J.; Hansma, Paul K.; Schmidt, Christoph F.

1995-03-01

39

Development anmd testing of electrophoresis solutions. Task I.1: Development of optimal buffer system  

NASA Technical Reports Server (NTRS)

Two buffers were explored for testing: low ionic strength electrophoresis buffer with and without density gradient material. It was found that the electrophoresis routine was better tolerated when Ficoll was present. The results of a viability study of primary human fetal kidney (HFK-1) cells at the first passage are shown. Cell strain HFK-1 was used in several experiments at the first and second passage. The HFK consisted mainly of fibroblasts, and HFK-1 has a high epithelioid cell content. The chromosomes of HFK were examined and found to be euploid. The stock medium for cell electrophoresis is described. In this solution density gradient solutes such as sucrose and Ficoll are dissolved to bring the osmolarity to 0.30. Its ionic strength is less than 0.01M, and its conductivity is usually 0.0011 mho/cm. Methods for viability determination included direct microscopic counting of the percent cells attached and spread within 24 hr of plating test cultures or electrophoretically separated fractions. The Cytograf viability assay concept was tested, and shown that blue stained cells scatter less light into the 0.8 to 3.3 deg angular interval than do unstained cells.

1985-01-01

40

Effect of phosphate buffer concentration on the heat resistance of Bacillus stearothermophilus spores suspended in parenteral solutions.  

PubMed Central

The effect of various quantities of Butterfield phosphate buffer added to four parenteral solutions on the survival of Bacillus stearothermophilus spores heated at 121 degrees C was determined. The effect of the addition of phosphate buffer on spore survival varied with the parenteral solution. Spore survival was increased or decreased, depending upon the composition of the parenteral solution and the buffer concentration. The results obtained in these experiments attest to the fact that environmental factors, including the type of ions present and ionic concentration, affect the heat destruction rate of B. stearothermophilus spores. Therefore, the sterilization requirements of a product such as a parenteral solution may be affected by small changes in formulation. PMID:727778

Gauthier, C A; Smith, G M; Pflug, I J

1978-01-01

41

Critical zinc[sup +2] activities for sour orange determined with chelator-buffered nutrient solutions  

SciTech Connect

Chelator-buffered nutrient solutions were used to study the effect of different levels of Zn activity in the rhizosphere on growth and nutritive responses of various tissues of sour orange seedlings. The seedlings were grown for 3 months in a growth chamber in a hydroponic culture containing from 5 to 69 [mu]m and 5 to 101 [mu]m total Zn in Expts. 1 and 2, respectively. Zn[sup +2] activities were calculated with a computerized chemical equilibrium model, and buffered by inclusion of a chelator, diethylenetriamine pentaacetate (DTPA), at 74 and 44 [mu]m in excess of the sum of Fe, Mn, Zn, Cu, Ni, and Co in Expts. 1 and 2, respectively. The use of DTPA-buffered solutions proved successful in imposing varying degrees of Zn deficiency. The deficiency was confirmed by leaf symptomatology, leaf chemical analyses, i.e., <16 mg[center dot]kg[sup [minus]1] Zn, and responses to foliar sprays and application of Zn to the roots. Growth parameters varied in their sensitivity to Zn deficiency, i.e., root dry weight < leaf number and white root growth < stem dry weight < leaf dry weight < shoot elongation and leaf area. The critical activities, expressed as pZn = [minus]log(Zn[sup +2]), were [approximately]10.2 [+-] 0.2 for root dry weight, 10.1 [+-] 0.2 for leaf number and white root growth, 10.0 [+-] 0.2 for stem dry weight, 9.9 [+-] 0.2 for leaf dry weight, and 9.8 [+-] 0.2 for shoot growth and leaf area. Increases in growth were observed in response to Zn applications even in the absence of visible Zn-deficiency symptoms. Seedlings containing > 23 mg[center dot]kg[sup [minus]1] Zn in leaves did not respond to further additions of Zn to the nutrient solution. Zinc foliar sprays were less effective than Zn applications to the roots in alleviating severe Zn deficiency because foliar-absorbed Zn was not translocated from the top of the roots and thus could not correct Zn deficiency in the roots.

Swietlik, D.; Zhang, L. (Texas A M Univ., Weslaco, TX (United States))

1994-07-01

42

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

PubMed

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?buffer solutions. Comparing the buffer A with buffer B unpaired Student's t-test showed statistically lower values (P?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

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

2013-06-01

43

Surface Morphology of Radiation-Grafted Binary Copolymers Measured in Buffer Solution under Swelling Condition  

NASA Astrophysics Data System (ADS)

pH-dependent binary graft copolymers, [polypropylene (PP)-g-2-(dimethylamino)ethylmethacrylate (DMAEMA)-g-N-isopropylacrylamide (NIPAAm) and (PP-g-4-vinylpyridine (4VP))-g-NIPAAm], synthesized by a two-step gamma-irradiation method, were characterized in terms of surface morphology under swelling condition. A confocal laser microscope with a water-immersion objective lens was employed for noncontact surface profile measurement of an extremely soft surface. Surface morphology was significantly different between these two binary copolymers, suggesting that the surface morphology of the binary copolymer reflected that of the first graft layer. Surface roughness was also analyzed as a function of the pH of the swelling buffer solution. Surface roughness increased with swelling ratio, and it further increased at lower pH, consistent with the results of a swelling ratio experiment previously reported.

Meléndez-Ortiz, Hector Ivan; Bucio, Emilio; Isoshima, Takashi; Ito, Hiromi; Hara, Masahiko

2010-01-01

44

Application of chelator-buffered nutrient solution technique in studies on zinc nutrition in rice plant (Oryza sativa L.)  

Microsoft Academic Search

It has been difficult to impose different degrees of Zn deficiency on Poaceae species in nutrient solution because most chelators which would control Zn to low activities also bind Fe3+ so strongly that Poaceae species cannot obtain adequate Fe. Recently, a method has been developed to provide buffered Fe2+ at levels adequate for rice using Ferrozine (FZ), and use of

X. Yang; V. Römheld; H. Marschner; R. L. Chaney

1994-01-01

45

Removal of alizarin red from aqueous solution by ethyl acetate green nanoemulsions.  

PubMed

The objective of the present study was to develop ethyl acetate (EA) green nanoemulsions for removal of alizarin red (AR) from water. Developed formulations were characterized in terms of thermodynamic stability, self-nanoemulsification efficiency, droplet size, polydispersity, viscosity, refractive index and per cent transmittance. Adsorption studies were performed by mixing small amounts of green nanoemulsions (1 ml) with relatively large amounts of AR solution (10 ml). It was observed that the droplet size, viscosity and % AR removal efficiency were influenced significantly by EA concentration of green nanoemulsions. However, contact time had negligible influence on % AR removal. Based on lowest droplet size (21.3 nm), lowest viscosity (19.3 Pa.s) and highest % AR removal efficiency (72.5%), green nanoemulsion E(1) containing 4.0% w/w of EA, 16.0% w/w of Triton-X100, 8.0% w/w of ethylene glycol and 72% w/w of water was optimized as the best green nanoemulsion composition for removal of AR from its bulk aqueous solution. PMID:25401323

Shakeel, Faiyaz; Haq, Nazrul; Alanazi, Fars K; Alsarra, Ibrahim A

2014-01-01

46

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

Microsoft Academic Search

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

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

1992-01-01

47

Synchronous Optical Packet Buffers  

Microsoft Academic Search

Synchronous optical packet buffering is presented as a solution for asynchronous time division multiplexed (TDM) optical packet switched networks. Truly asynchronous optical packet synchronization and buffering are demonstrated using multiple independent transmitters, synchronous optical buffers, and a burst mode receiver. Optical packet synchronizers are used to dynamically align incoming asynchronous packets to local timeslots for synchronous loading of buffers. Multiple

John P. Mack; Emily F. Burmeister; John M. Garcia; Henrik N. Poulsen; Biljana Stamenic; Geza Kurczveil; Kimchau N. Nguyen; Kurtis Hollar; John E. Bowers; Daniel J. Blumenthal

2010-01-01

48

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

SciTech Connect

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

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

1999-05-01

49

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

PubMed Central

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

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

2006-01-01

50

Structural characterization of apomyoglobin self-associated species in aqueous buffer and urea solution.  

PubMed

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

Chow, Charles; Kurt, Nese; Murphy, Regina M; Cavagnero, Silvia

2006-01-01

51

Subcritical Delamination of Dielectric and Metal Films from Low-k Organosilicate Glass (OSG) Thin Films in Buffered pH Solutions  

E-print Network

(OSG) films in pH buffer solutions was studied in this work. Crack path and subcritical fracture of the crack velocity curves for both systems are independent of pH as predicted by the model. Near transport results on subcritical cracking of OSG/TaN and OSG/SiNx films in buffered pH solutions. These data were

52

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

53

Plant uptake of 14 C-EDTA, 14 C-Citrate, and 14 C-Histidine from chelator-buffered and conventional hydroponic solutions  

Microsoft Academic Search

Chelator-buffered hydroponic solutions provide low and buffered free-metal concentrations and allow the easy calculation of nutrient species expected in these solutions. Some researchers suspect that the solutions allow plant uptake of chelates and that this uptake explains the failure of the free-ion activity model using these solutions. To determine the amount and method of chelate uptake, swiss chard was grown

Paul F. Bell; M. J. McLaughlin; G. Cozens; D. P. Stevens; G. Owens; H. South

2003-01-01

54

The Cardiovascular Effect of the Uremic Solute Indole-3 Acetic Acid.  

PubMed

In CKD, uremic solutes may induce endothelial dysfunction, inflammation, and oxidative stress, leading to increased cardiovascular risk. We investigated whether the uremic solute indole-3 acetic acid (IAA) predicts clinical outcomes in patients with CKD and has prooxidant and proinflammatory effects. We studied 120 patients with CKD. During the median study period of 966 days, 29 patients died and 35 experienced a major cardiovascular event. Kaplan-Meier analysis revealed that mortality and cardiovascular events were significantly higher in the higher IAA group (IAA>3.73 µM) than in the lower IAA group (IAA<3.73 µM). Multivariate Cox regression analysis demonstrated that serum IAA was a significant predictor of mortality and cardiovascular events after adjustments for age and sex; cholesterol, systolic BP, and smoking; C-reactive protein, phosphate, body mass index, and albumin; diastolic BP and history of cardiovascular disease; and uremic toxins p-cresyl sulfate and indoxyl sulfate. Notably, IAA level remained predictive of mortality when adjusted for CKD stage. IAA levels were positively correlated with markers of inflammation and oxidative stress: C-reactive protein and malondialdehyde, respectively. In cultured human endothelial cells, IAA activated an inflammatory nongenomic aryl hydrocarbon receptor (AhR)/p38MAPK/NF-?B pathway that induced the proinflammatory enzyme cyclooxygenase-2. Additionally, IAA increased production of endothelial reactive oxygen species. In conclusion, serum IAA may be an independent predictor of mortality and cardiovascular events in patients with CKD. In vitro, IAA induces endothelial inflammation and oxidative stress and activates an inflammatory AhR/p38MAPK/NF-?B pathway. PMID:25145928

Dou, Laetitia; Sallée, Marion; Cerini, Claire; Poitevin, Stéphane; Gondouin, Bertrand; Jourde-Chiche, Noemie; Fallague, Karim; Brunet, Philippe; Calaf, Raymond; Dussol, Bertrand; Mallet, Bernard; Dignat-George, Françoise; Burtey, Stephane

2014-08-21

55

Using a chelate-buffered nutrient solution to establish the critical solution activity of Mn 2+ required by barley ( Hordeum vulgare L.)  

Microsoft Academic Search

Relatively little is known about the responses of plants to micronutrients when these nutrients are maintained at the very low levels found in soils of low fertility. We have determined the requirement of barley (Hordeum vulgare L. cv Herta) for ionic Mn2+ in plant culture solutions using the chelating agent HEDTA as a buffer for micronutrient metal ions. The chemical

M. J. Webb; W. A. Norvell; R. M. Welch; R. D. Graham

1993-01-01

56

High-performance polymer solar cells with solution-processed and environmentally friendly CuOx anode buffer layer.  

PubMed

Highly efficient polymer solar cells (PSCs) are demonstrated by introducing environmentally friendly CuOx as hole extraction anode buffer layer. The CuOx buffer layer is prepared simply via spin-coating 1,2-dichlorobenzene solution of Copper acetylacetonate on the ITO substrate and thermal transformation (at 80 °C) in air. Remarkable improvements in the open-circuit voltage (Voc) and short-circuit current density (Jsc) of the PSCs could be achieved upon the introduction of CuOx buffer layer. The study about the effect of CuOx interfacial layer on the device resistances demonstrates that insertion of CuOx layer can decrease the whole resistance of the PSCs. For the devices based on P3HT:PCBM, the power conversion efficiency (PCE) was increased from 2.8% (the reference device without buffer layer) to 4.1% via introduction of CuOx hole extraction layer. The PCE of the PSC was further increased to 6.72% when ICBA used as an alternative acceptor to PCBM. The much higher PCE of 7.14% can be achieved by adopting PBDTTT-C, a low band gap conjugated polymer, as donor material. The results demonstrate that CuOx has great potential as a hole extraction material for highly efficient PSCs. PMID:24094978

Xu, Qi; Wang, Fuzhi; Tan, Zhan'ao; Li, Liangjie; Li, Shusheng; Hou, Xuliang; Sun, Gang; Tu, Xiaohe; Hou, Jianhui; Li, Yongfang

2013-11-13

57

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

PubMed

Multipurpose solutions (MPS) often contain low concentrations of boric acid as a buffering agent. Limited published literature has suggested that boric acid and borate-buffered MPS may alter the corneal epithelium; an effect attributed to cytotoxicity induced by boric acid. However, this claim has not been substantiated. We investigated the effect of treating cells with relevant concentrations of boric acid using two cytotoxicity assays, and also assessed the impact of boric acid on corneal epithelial barrier function by measuring TEER and immunostaining for tight junction protein ZO-1 in human corneal epithelial cells. Boric acid was also assessed in an in vivo ocular model when administered for 28 days. Additionally, we evaluated Biotrue multi-purpose solution, a novel borate-buffered MPS, alone and with contact lenses for ocular compatibility in vitro and in vivo. Boric acid passed both cytotoxicity assays and did not alter ZO-1 distribution or corneal TEER. Furthermore, boric acid was well-tolerated on-eye following repeated administration in a rabbit model. Finally, Biotrue multi-purpose solution demonstrated good ocular biocompatibility both in vitro and in vivo. This MPS was not cytotoxic and was compatible with the eye when administered alone and when evaluated with contact lenses. We demonstrate that boric acid and a borate-buffered MPS is compatible with the ocular environment. Our findings provide evidence that ocular effects reported for some borate-buffered MPS may be incorrectly attributed to boric acid and are more likely a function of the unique combination of ingredients in the MPS formulation tested. PMID:21115387

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

2010-12-01

58

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

SciTech Connect

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

Sundaramurthi, Prakash; Suryanarayanan, Raj (UMM)

2011-09-06

59

In Vitro NER Assay Yeast extraction Buffer (200 ml): 0.2 M Tris-acetate (pH 7.5) (40 ml), 0.39 M  

E-print Network

/v) DSD in water. Store at room temperature. Proteinase K: Make 20 mg/ml in water. Store in 50-µl aliquots at -20°C. 10 mg/ml RNase A: make in water. Boil for 10 minutes to inactivate DNase. Store at -20°CAuble Lab In Vitro NER Assay Reagents: Water YPD Yeast extraction Buffer (200 ml): 0.2 M Tris

Auble, David

60

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

61

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

Microsoft Academic Search

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

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

1997-01-01

62

Photo-electrochemical analysis of passive film formed on X80 pipeline steel in bicarbonate/carbonate buffer solution  

NASA Astrophysics Data System (ADS)

Photo-electrochemical measurement was used to explore the formation potential, formation time, chloride ions concentration, applied potential and pH value of the solution on the electronic property of passive film formed on X80 pipeline steel in 1 M NaHCO 3/0.5 M Na 2CO 3 buffer solution. The results showed that the photocurrent is positive, indicating an n-type semiconductor character of the passive film, the photocurrent increased with increasing the formation potential, prolonging the formation time, decreasing chloride ions concentration, rising applied potential and decreasing the pH value of the solution. Capacitance measurement exhibited a positive slope of Mott-Schottky plot, and the slopes of Mott-Schottky plots increased with the increasing formation potential, showing a decrement of the donor density of the passive film.

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

2008-02-01

63

High-efficiency Cd-free CIGSS thin-film solar cells with solution grown zinc compound buffer layers  

Microsoft Academic Search

Zn-compounds Zn(X,OH) (X=S,Se) buffer layers have been deposited by chemical bath (CBD) process on Cu(In,Ga)(S,Se)2 (CIGSS) with the aim of developing Cd-free CIGSS-based devices. The films are produced in alkaline aqueous solution containing ZnSO4, ammonia NH3 and XC(NH2)2. Optimum deposition conditions were established. The temperature (Tsub) of the chemical bath is found to be critical for the device quality. The

A. Ennaoui; S. Siebentritt; M. Ch. Lux-Steiner; W. Riedl; F. Karg

2001-01-01

64

Ca2+ handling by rat myocardium exposed to ATP solutions of different [Ca2+] and Ca2+ buffering capacity.  

PubMed

Cardiac preparations from the right ventricular wall of rats were exposed to ATP-containing solutions of different Ca2+ concentrations ([Ca2+]) and Ca2+ buffering capacity to determine whether such treatments affected the Ca2+ handling properties of the cardiac muscle. Exposure to 8 mM extracellular ATP (ATP0) elicited sustained, near-maximal contractures that were due to Ca2+ entry from the extracellular environment and severely diminished cardiac excitability in a partially reversible manner. At 1 mM ATP0, there was a sustained rise in diastolic force and intracellular [Ca2+] and a marked, partially reversible change in the stimulation-induced Ca2+ transients measured with fura 2. A large, transient contracture was also observed when the intact ventricular preparations were transferred from the normal physiological solution to an ATP-containing (8 mM) relaxing solution (ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid < or = 0.2 mM, < 10 nM Ca2+) with or without saponin (50 micrograms/ml). The ATP0-induced contractures were dependent on the prevalent conditions with respect to [Ca2+] and Ca2+ buffering capacity of the solutions and were associated with heavy Ca2+ loading of the sarcoplasmic reticulum (SR) and mitochondria, a less leaky SR, and a reduced SR sensitivity to the SR Ca2+ pump blocker 2,5-di-tert-butyl hydroquinone. The results indicate that the Ca2+ handling properties and the electrical excitability of ventricular preparations can be markedly modified by exposure to ATP0 and that conditions prevalent during skinning with saponin are important in determining the properties of the intracellular Ca2+ stores. PMID:9321825

Kabbara, A A; Stephenson, D G

1997-09-01

65

An evaluation of MES (2(N-Morpholino)ethanesulfonic acid) and Amberlite IRC-50 as pH buffers for nutrient solution studies  

NASA Technical Reports Server (NTRS)

All buffering agents used to stabilize pH in hydroponic research have disadvantages. Inorganic buffers are absorbed and may become phytotoxic. Solid carbonate salts temporarily mitigate decreasing pH but provide almost no protection against increasing pH, and they alter nutrient absorption. Exchange resins are more effective, but we find that they remove magnesium and manganese from solution. We have tested 2(N-Morpholino)ethanesulfonic acid (MES) as a buffering agent at concentrations of 1 and 10 mol m-3 (1 and 10 mM) with beans, corn, lettuce, tomatoes, and wheat. MES appears to be biologically inert and does not interact significantly with other solution ions. Relative growth rates among controls and MES treatments were nearly identical for each species during the trial period. The pH was stabilized by 1 mol m-3 MES. This buffer warrants further consideration in nutrient research.

Bugbee, B. G.; Salisbury, F. B.

1985-01-01

66

Influence of buffer solution composition on drug release from pellets coated with neutral and quaternary acrylic polymers and on swelling of free polymer films  

Microsoft Academic Search

Aqueous dispersions of the acrylic resins poly(ethylacrylate-methylmethacrylate-trimethylammonioethyl methacrylate chloride) (quaternary PMMA, Eudragit RS30D) and poly(ethylacrylate-methylmethacrylate) (neutral PMMA, Eudragit NE30D) were used to cast free films and to coat theophylline pellets. The release of theophylline from pellets coated with Eudragit RS showed a great dependence on the composition of the buffer solution. The highest release rates were observed in formate buffers;

Klaus Knop

1996-01-01

67

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

PubMed Central

Introduction As even small concentrations of acetate in the plasma result in pro-inflammatory and cardiotoxic effects, it has been removed from renal replacement fluids. However, Plasma-Lyte 148 (Plasma-Lyte), an electrolyte replacement solution containing acetate plus gluconate is a common circuit prime for cardio-pulmonary bypass (CPB). No published data exist on the peak plasma acetate and gluconate concentrations resulting from the use of Plasma-Lyte 148 during CPB. Methods Thirty adult patients were systematically allocated 1:1 to CPB prime with either bicarbonate-balanced fluid (24 mmol/L bicarbonate) or Plasma-Lyte 148. Arterial blood acetate, gluconate and interleukin-6 (IL-6) levels were measured immediately before CPB (T1), three minutes after CPB commencement (T2), immediately before CPB separation (T3), and four hours post separation (T4). Results Acetate concentrations (normal 0.04 to 0.07 mmol/L) became markedly elevated at T2, where the Plasma-Lyte group (median 3.69, range (2.46 to 8.55)) exceeded the bicarbonate group (0.16 (0.02 to 3.49), P < 0.0005). At T3, levels had declined but the differential pattern remained apparent (Plasma-Lyte 0.35 (0.00 to 1.84) versus bicarbonate 0.17 (0.00 to 0.81)). Normal circulating acetate concentrations were not restored until T4. Similar gluconate concentration profiles and inter-group differences were seen, with a slower T3 decay. IL-6 increased across CPB, peaking at T4, with no clear difference between groups. Conclusions Use of acetate containing prime solutions result in supraphysiological plasma concentrations of acetate. The use of acetate-free prime fluid in CPB significantly reduced but did not eliminate large acetate surges in cardiac surgical patients. Complete elimination of acetate surges would require the use of acetate free bolus fluids and cardioplegia solutions. Trial registration Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12610000267055 PMID:21235742

2011-01-01

68

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

NASA Astrophysics Data System (ADS)

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

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

2002-04-01

69

Influence of ammonia solution on gastric mucosa and acetic acid induced ulcer in rats.  

PubMed

Aqueous ammonia in concentrations of 0.02 or 0.1% was continuously administered to rats to study its effect on the gastric mucosa histologically and cell kinetically. Furthermore, acetic acid ulcer, which is a model of chronic gastric ulcer, was experimentally induced in the stomachs of rats to assess the influence of 0.02% ammonia on the course of this ulcer. Male Donryu rats were divided into three groups given 0.02% ammonia, 0.1% ammonia or tap water. On several occasions (1, 3 and 5 days and 1, 4, 8, 12 and 24 weeks from the beginning of the experiment), the gastric mucosa in the fundic gland region and the antrum was examined histologically, and from the viewpoint of cell kinetics. The assessment in the 8th and 24th weeks employed the double labeling technique with bromodeoxyuridine and 3H-thymidine. The assessment on the other occasions used the flash labeling technique with bromodeoxyuridine. Both the 0.02% and 0.1% ammonia treatment groups showed a decrease in PAS-positive mucus and an enhanced cell cycling in the early stage of the experiment. After long periods of treatment, these groups showed a reduction in the gland height, a recovery in PAS-positive mucus and a suppression of cell cycle, suggesting direct toxicity of ammonia on the gastric mucosa. Although glandular atrophy was observed in these animals, infiltration of inflammatory cells was not observed. Thus, the relationship between ammonia and gastritis remained obscure. No ulcer developed in any group. Subsequently, we experimentally induced Ul-IV or Ul-V acetic acid ulcers in the stomachs of rats, according to the method of Okabe et al. (1971, 1972). These rats were divided into two groups given 0.02% ammonia or tap water. In the 4th and 8th weeks of the experiment, the stomachs of these rats were examined histologically and from the viewpoint of cell kinetics. The 0.02% ammonia treatment group showed a significant increase in the ulcer index (long diameter x short diameter; mm2) in the 4th and 8th weeks. This group also showed suppressed cell cycling of the regenerative epithelium and fibroblasts in the ulcer margin, suggesting direct toxicity of ammonia. Thus, healing of peptic ulcer was delayed by continuous administration of 0.02% ammonia. PMID:7517730

Hata, M; Yamazaki, Y; Ueda, T; Kato, T; Kohli, Y; Fujiki, N

1994-01-01

70

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

PubMed

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

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

2013-10-01

71

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

PubMed

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

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

2011-12-01

72

Effect of Free Manganese Activity on Yield and Uptake of Micronutrient Cations by Barley and Oat grown in Chelator-buffered Nutrient Solution  

Microsoft Academic Search

The uptake of micronutrient cations in relation to varying activities of Mn was studied for barley (Hordeum vulgare L. var. Thule) and oat (Avena sativa L. var. Biri) grown in chelator buffered nutrient solution. Free activities of Mn were calculated by using the chemical speciation programme GEOCHEM-PC. Manganese deficient conditions induced elevated concentrations of Zn and Fe in shoots of

Peder Lombnæs; Bal Ram Singh

2003-01-01

73

Xyloglucan nano-aggregates: Physicochemical characterisation in buffer solution and potential application as a carrier for camptothecin, an anti-cancer drug  

Microsoft Academic Search

In this work, native xyloglucan was extracted from Tamarindus indica seeds (XGT), and its properties in phosphate buffer solution (PBS) were evaluated in comparison with a commercial tamarind kernel powder (TKP). The physico-chemical characteristics of the polysaccharides such as molar mass, critical concentration and intrinsic viscosity were determined. Furthermore, using spectroscopic and microscopy techniques, it was observed that the XGs

Tatiane A. Jó; Denise F. S. Petri; Leila M. Beltramini; Neoli Lucyszyn; Maria Rita Sierakowski

2010-01-01

74

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

USGS Publications Warehouse

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

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

1988-01-01

75

Protein-Water and Protein-Buffer Interactions in the Aqueous Solution of an Intrinsically Unstructured Plant Dehydrin: NMR Intensity and DSC Aspects  

Microsoft Academic Search

Proton NMR intensity and differential scanning calorimetry measurements were carried out on an intrinsically unstructured late embryogenesis abundant protein, ERD10, the globular BSA, and various buffer solutions to characterize water and ion binding of proteins by this novel combination of experimental approaches. By quantifying the number of hydration water molecules, the results demonstrate the interaction between the protein and NaCl

P. Tompa; P. Banki; M. Bokor; P. Kamasa; D. Kovacs; G. Lasanda; K. Tompa

2006-01-01

76

Thermodynamical characteristics of the reaction of pyridoxal-5'-phosphate with L-amino acids in aqueous buffer solution  

NASA Astrophysics Data System (ADS)

The reaction of pyridoxal-5'-phosphate with L-isomers of alanine, lysine, arginine, aspartic acid, glutamic acid, and glycine in phosphate buffer solution was studied by absorption spectroscopy and the calorimetry of dissolution at physiological acidity of the medium (pH 7.35). The formation constants of Schiff bases during reactions and changes in Gibbs energy, enthalpy, and entropy were determined. It was shown that the formation constant of the Schiff base and its spectral properties depend on the nature of the bound amino acid. The progress of the reaction with a majority of amino acids is governed by the entropy factor due to the predominant role of the dehydration effect of the reaction center of amino acids during chemical reactions. The intramolecular electrostatic interaction of an ionized phosphate group with the positively charged amino group on the end of the chain of amino acid residue stabilizes the Schiff bases formed by lysine and arginine. The extinction coefficient of the base, equilibrium constant, and the exothermic effect of the reaction then increase. The excess negative charge on the end of the chain of amino acid residues of aspartic and glutamic acids destabilizes the molecule of the Schiff base. In this case, the equilibrium constant decreases and the endothermic effect of the reaction increases.

Barannikov, V. P.; Badelin, V. G.; Venediktov, E. A.; Mezhevoi, I. N.; Guseinov, S. S.

2011-01-01

77

Diffusion of 1-Ethyl-3-methyl-imidazolium Acetate in Glucose, Cellobiose, and Cellulose Solutions  

PubMed Central

Solutions of glucose, cellobiose and microcrystalline cellulose in the ionic liquid 1-ethyl-3-methyl-imidazolium ([C2mim][OAc]) have been examined using pulsed-field gradient 1H NMR. Diffusion coefficients of the cation and anion across the temperature range 20–70 °C have been determined for a range of concentrations (0–15% w/w) of each carbohydrate in [C2mim][OAc]. These systems behave as an “ideal mixture” of free ions and ions that are associated with the carbohydrate molecules. The molar ratio of carbohydrate OH groups to ionic liquid molecules, ?, is the key parameter in determining the diffusion coefficients of the ions. Master curves for the diffusion coefficients of cation, anion and their activation energies are generated upon which all our data collapses when plotted against ?. Diffusion coefficients are found to follow an Arrhenius type behavior and the difference in translational activation energy between free and associated ions is determined to be 9.3 ± 0.9 kJ/mol. PMID:24405090

2014-01-01

78

Contribution of Solution pH and Buffer Capacity to Suppress Intergranular Stress Corrosion Cracking of Sensitized Type 304 Stainless Steel at 95?C  

Microsoft Academic Search

Controlling pH of high-temperature water to [approximately]pH 7 at 300 C by adding lithium hydroxide (LiOH) into the coolant system of a pressurized water reactor (PWR) successfully has been mitigating the corrosion of PWR component materials. The effects of solution pH and buffer capacity on intergranular stress corrosion cracking (IGSCC) of sensitized type 304 stainless steel ([SS] UNS S30400) was

S. Zhang; T. Shibata; T. Haruna

1999-01-01

79

The dissolution and passivation of polycrystalline iron electrodes in boric acid-borate buffer solutions in the 7.5–9.2 pH range  

Microsoft Academic Search

The voltammetric responses of iron in boric acid-borate buffer solutions in the 7.5–9.2 pH range and 0–75°C range show two different and successive stages related to passivation. The first electro-oxidation stage leading to passivity onset corresponds to Fe(OH)2 electroformation. The second stage corresponds to the growth and second level electro-oxidation of the prepassive layer.

M. E. Vela; J. R. Vilche; A. J. Arvia

1986-01-01

80

New process for producing cellulose acetate from wood in concentrated acetic acid  

Microsoft Academic Search

To explore further potential applications of acetic acid pulp, an investigation was conducted to develop a direct method for producing cellulose acetate from wood in combination with atmospheric acetic acid pulping. The process consists of delignification, totally chlorine-free bleaching, and esterification, with the concentrated acetic acid aqueous solution being used as only solvent throughout the process. The acetic acid pulp

Hironori Sato; Yasumitsu Uraki; Takao Kishimoto; Yoshihiro Sano

2003-01-01

81

Contribution of solution pH and buffer capacity to suppress intergranular stress corrosion cracking of sensitized type 304 stainless steel at 95 C  

SciTech Connect

Controlling pH of high-temperature water to [approximately]pH 7 at 300 C by adding lithium hydroxide (LiOH) into the coolant system of a pressurized water reactor (PWR) successfully has been mitigating the corrosion of PWR component materials. The effects of solution pH and buffer capacity on intergranular stress corrosion cracking (IGSCC) of sensitized type 304 stainless steel ([SS] UNS S30400) was examined at 95 C by slow strain rate technique (SSRT) with an in-situ cracking observation system. It was found that an increase in solution pH or buffer capacity increased crack initiation time and decreased mean crack initiation frequency, but exerted almost no effect on crack propagation. This inhibition effect on IGSCC initiation was explained as resulting from a retarding effect of solution pH and buffer capacity on the decrease in pH at crack nuclei caused by the hydrolysis of metal ions dissolved when the passive film was ruptured by strain in SSRT.

Zhang, S.; Shibata, T.; Haruna, T. (Osaka Univ., Suita, Osaka (Japan). Dept. of Materials Science and Processing)

1999-05-01

82

Molecular Structure of Sodium acetate  

NSDL National Science Digital Library

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

2002-08-26

83

[(3)H]Adenine is a suitable radioligand for the labeling of G protein-coupled adenine receptors but shows high affinity to bacterial contaminations in buffer solutions.  

PubMed

[(3)H]Adenine has previously been used to label the newly discovered G protein-coupled murine adenine receptors. Recent reports have questioned the suitability of [(3)H]adenine for adenine receptor binding studies because of curious results, e.g. high specific binding even in the absence of mammalian protein. In this study, we showed that specific [(3)H]adenine binding to various mammalian membrane preparations increased linearly with protein concentration. Furthermore, we found that Tris-buffer solutions typically used for radioligand binding studies (50 mM, pH 7.4) that have not been freshly prepared but stored at 4 degrees C for some time may contain bacterial contaminations that exhibit high affinity binding for [(3)H]adenine. Specific binding is abolished by heating the contaminated buffer or filtering it through 0.2-mum filters. Three different, aerobic, gram-negative bacteria were isolated from a contaminated buffer solution and identified as Achromobacter xylosoxidans, A. denitrificans, and Acinetobacter lwoffii. A. xylosoxidans, a common bacterium that can cause nosocomial infections, showed a particularly high affinity for [(3)H]adenine in the low nanomolar range. Structure-activity relationships revealed that hypoxanthine also bound with high affinity to A. xylosoxidans, whereas other nucleobases (uracil, xanthine) and nucleosides (adenosine, uridine) did not. The nature of the labeled site in bacteria is not known, but preliminary results indicate that it may be a high-affinity purine transporter. We conclude that [(3)H]adenine is a well-suitable radioligand for adenine receptor binding studies but that bacterial contamination of the employed buffer solutions must be avoided. PMID:18404448

Schiedel, Anke C; Meyer, Heiko; Alsdorf, Bernt B A; Gorzalka, Simone; Brüssel, Hannelore; Müller, Christa E

2007-09-01

84

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

PubMed

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

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

2013-12-11

85

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

NASA Astrophysics Data System (ADS)

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

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

86

Free flow cell electrophoresis using zwitterionic buffer  

NASA Technical Reports Server (NTRS)

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.

Rodkey, R. Scott

1990-01-01

87

Solid phase extraction of proteins from buffer solutions employing capillary-channeled polymer (C-CP) fibers as the stationary phase.  

PubMed

Polypropylene (PP) capillary-channeled polymer (C-CP) fibers are applied for solid phase extraction (SPE) of proteins from aqueous buffer solutions using a micropipette tip-based format. A process was developed in which centrifugation is used as the moving force for solution passage in the loading/washing steps instead of the previously employed manual aspiration. The complete procedure requires ~15 minutes, with the number of samples run in parallel limited only by the capacity of the centrifuge. The method performance was evaluated based on adsorption and elution characteristics of several proteins (cytochrome c, lysozyme, myoglobin, and glucose oxidase) from 150 mM phosphate buffered saline (PBS) solutions. Protein concentration ranges of ~2 to 100 ?g mL(-1) were employed and the recovery characteristics determined through UV-Vis absorbance spectrophotometry for protein quantification. The protein loading capacities across the range of proteins was ~1.5 ?g for the 5 mg fiber tips. Average recoveries from PBS were determined for each protein sample; cytochrome c ~86%, lysozyme ~80%, myoglobin ~86%, and glucose oxidase ~89%. Recoveries from more complex matrices, synthetic urine and synthetic saliva, were determined to be ~90%. A 10× dilution study for a fixed 1 ?g protein application yielded 94 ± 3.2% recoveries. The C-CP tips provided significantly higher recoveries for myoglobin in a 150 mM PBS matrix in comparison to a commercially available protein SPE product, with the added advantages of low cost, rapid processing, and reusability. PMID:23223274

Burdette, Carolyn Q; Marcus, R Kenneth

2013-02-21

88

Buffer Biology.  

ERIC Educational Resources Information Center

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

Morgan, Kelly

2000-01-01

89

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

PubMed

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

Verheyen, Liesbeth; Versieren, Liske; Smolders, Erik

2014-09-01

90

YBa2Cu3Ox Thin Films with Yttria Stabilized Zirconia Buffer Layer on Metal Substrate by Liquid Source Chemical Vapor Deposition Using Tetrahydrofuran Solution of beta-Diketonates  

Microsoft Academic Search

Textured YBa2Cu3O x (YBCO) thin films with c-axis orientation on Ni-based metal substrate with yttria stabilized zirconia (YSZ) and Pt buffer layers were formed by liquid source chemical vapor deposition (LS-CVD) using tetrahydrofuran (THF) solution of beta-diketonates. The YSZ buffer layer with a-axis orientation was formed by the similar LS-CVD on prebuffer layers of amorphous YSZ and Pt deposited by

Shigeru Matsuno; Toshio Umemura; Fusaoki Uchikawa; Bunko Ikeda

1995-01-01

91

Methane from acetate.  

PubMed Central

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

Ferry, J G

1992-01-01

92

In-Line Desalting of Proteins from Buffer and Synthetic Urine Solution Prior to ESI-MS Analysis via a Capillary-Channeled Polymer Fiber Microcolumn  

NASA Astrophysics Data System (ADS)

Presented here is a novel in-line solid phase extraction (SPE) method utilizing a capillary-channeled polymer (C-CP) fiber microcolumn prior to introduction to an electrospray ionization (ESI) source. The high permeability of the microcolumn allows for operation under syringe pump or HPLC driven flow, ultimately providing greater mass spectral clarity and accurate molecular weight determinations for different protein/buffer combinations. Studies presented here focus on the desalting of several target proteins from a standard phosphate buffered saline (PBS) matrix and a synthetic urine solution prior to ESI-MS determinations. In every case, responses for ?M-level proteins in PBS improve from the situation of not permitting molecular weight determinations to values that are precise to better than ±10 Da, without internal standards, with relative improvements in the signal-to-background ratios (S/B) on the order of 3,000×. De-salting of a myoglobin-spiked (12 ?M) synthetic urine results in equally-improved spectral quality.

Burdette, Carolyn Q.; Marcus, R. Kenneth

2013-06-01

93

The use of ethylene glycol solution as the running buffer for highly efficient microchip-based electrophoresis in unmodified cyclic olefin copolymer microchips.  

PubMed

An ethylene glycol solution was used as the electrophoretic running buffer in unmodified cyclic olefin copolymer (COC) microchips to minimize the interactions between the analytes and the hydrophobic walls of the plastic microchannels, enhance the resolution of the analytes and eliminate the uncontrollable dispersion caused by uneven liquid levels and non-uniform surfaces of the separation channels. Five amino acids that were labeled with fluorescein isothiocyanate (FITC) were used as model analytes to examine the separation efficiency. The effects of ethylene glycol concentration, pH and sodium tetraborate concentration were systematically investigated. The five FITC-labeled amino acids were effectively resolved using a COC microchip with an effective length of 2.5 cm under optimum conditions, which included using a running buffer of 20 mmol/L sodium tetraborate in ethylene glycol:water (80:20, v/v), pH 6.7. A theoretical plate number of 4.8 × 10(5)/m was obtained for aspartic acid. The system exhibited good repeatability, and the relative standard deviations (n=5) of the peak areas and migration times were no more than 3.4% and 0.7%, respectively. Furthermore, the system was successfully applied to elucidate these five amino acids in human saliva. PMID:22099226

Wang, Qin; Zhang, Yuan; Ding, Hui; Wu, Jing; Wang, Lili; Zhou, Lei; Pu, Qiaosheng

2011-12-30

94

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

95

Volumetric Investigations on Interactions of Acidic\\/Basic Amino Acids with Sodium Acetate, Sodium Propionate and Sodium Butyrate in Aqueous Solutions  

Microsoft Academic Search

The apparent molar volumes, V\\u000a \\u000a ?\\u000a , of L-aspartic acid, L-glutamic acid, L-lysine monohydrate and L-arginine in water and in aqueous (0.1, 0.25, 0.5 and 1.0)\\u000a mol?kg?1 sodium acetate and sodium propionate, and (0.1, 0.25 and 0.5) mol?kg?1 sodium butyrate solutions have been determined at 288.15, 298.15, 308.15 and 318.15 K from density measurements. The partial\\u000a molar volumes at infinite dilution, V\\u000a 2o, obtained

Tarlok S. Banipal; Kultar Singh; Parampaul K. Banipal

2007-01-01

96

The variation of viscosity, refractive indices, compressibility, intermolecular free length, and excess molar volume of the acetophenone—ethyl acetate solutions at 303.15-323.15 K  

NASA Astrophysics Data System (ADS)

Densities, viscosities, refractive indices and ultrasonic velocities of the binary mixtures of acetophenone with ethyl acetate were measured over the entire mole fractions at 303.15, 313.15, and 323.15 K. From the experimental results, excess molar volumes V E, viscosity deviation ??, refractive index deviation ? n D , deviations in isentropic compressibility ?? s and excess intermolecular free length ? L f are calculated. The viscosity values were fitted to the models of Krishnan-Laddha and McAllister. The thermophysical properties under study were fit to the Jouyban-Acree model. The excess values were correlated using Redlich-Kister polynomial equation to obtain their coefficients and standard deviations. The data obtained fitted with the values correlated by the corresponding models very well. The results are interpreted in terms of molecular interactions occurring in the solution.

Saravanakumar, K.; Baskaran, R.; Kubendran, T. R.

2012-12-01

97

Kinetic buffers.  

PubMed

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. PMID:25387452

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

2015-01-12

98

Molecular Structure of Phenylmercuric acetate  

NSDL National Science Digital Library

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

2004-11-10

99

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

100

REMOTE Shared Memory Buffer #2  

E-print Network

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

101

Effects of sodium hypochlorite and high pH buffer solution in electrokinetic soil treatment on soil chromium removal and the functional diversity of soil microbial community.  

PubMed

Effects of sodium hypochlorite (NaClO), applied as an oxidant in catholyte, and high pH buffer solution on soil Cr removal and the functional diversity of soil microbial community during enhanced electrokinetic treatments of a chromium (Cr) contaminated red soil are evaluated. Using pH control system to maintain high alkalinity of soil together with the use of NaClO increased the electrical conductivities of soil pore liquid and electroosmotic flux compared with the control (Exp-01). The pH control and NaClO improved the removal of Cr(VI) and total Cr from the soil. The highest removal percentages of soil Cr(VI) and total Cr were 96 and 72%, respectively, in Exp-04 when the pH value of the anolyte was controlled at 10 and NaClO was added in the catholyte. The alkaline soil environment and introduction of NaClO in the soil enhanced the desorption of Cr(VI) from the soil and promoted Cr(III) oxidation to mobile Cr(VI), respectively. However, the elevated pH and introduction of NaClO in the soil, which are necessary for improving the removal efficiency of soil Cr, resulted in a significantly adverse impact on the functional diversity of soil microbial community. It suggests that to assess the negative impact of extreme conditions for enhancing the extraction efficiencies of Cr on the soil properties and function is necessary. PMID:16956724

Cang, Long; Zhou, Dong-Mei; Alshawabkeh, Akram N; Chen, Hai-Feng

2007-04-01

102

Effect of synovial fluid, phosphate-buffered saline solution, and water on the dissolution and corrosion properties of CoCrMo alloys as used in orthopedic implants.  

PubMed

The corrosion and dissolution of high- and low-carbon CoCrMo alloys, as used in orthopedic joint replacements, were studied by immersing samples in phosphate-buffered saline (PBS), water, and synovial fluid at 37 degrees C for up to 35 days. Bulk properties were analyzed with a fine ion beam microscope. Surface analyses by X-ray photoelectron spectroscopy and Auger electron spectroscopy showed surprisingly that synovial fluid produced a thin oxide/hydroxide layer. Release of ions into solution from the alloy also followed an unexpected pattern where synovial fluid, of all the samples, had the highest Cr concentration but the lowest Co concentration. The presence of carbide inclusions in the alloy did not affect the corrosion or the dissolution mechanisms, although the carbides were a significant feature on the metal surface. Only one mechanism was recognized as controlling the thickness of the oxide/hydroxide interface. The analysis of the dissolved metal showed two mechanisms at work: (1) a protein film caused ligand-induced dissolution, increasing the Cr concentration in synovial fluid, and was explained by the equilibrium constants; (2) corrosion at the interface increased the Co in PBS. The effect of prepassivating the samples (ASTM F-86-01) did not always have the desired effect of reducing dissolution. The release of Cr into PBS increased after prepassivation. The metal-synovial fluid interface did not contain calcium phosphate as a deposit, typically found where samples are exposed to calcium rich bodily fluids. PMID:15900610

Lewis, A C; Kilburn, M R; Papageorgiou, I; Allen, G C; Case, C P

2005-06-15

103

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

USGS Publications Warehouse

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

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

1994-01-01

104

[Metabolism of C(14)-acetate by some trematodes  

PubMed

The adult trematodes, Fasciola hepatica, Eurytrema pancreaticum and Paramphistomum cervi, employed in this experiment were obtained from the cattle slaughtered at the local abbatoir. The worms selected and washed several times in normal sterilized saline solution. Each about ten of intact F. hepatica, fourty of E. pancreaticum, and twenty of P. cervi were incubated in 50 cc volume of special incubation flasks with incubation medium consisting of 10 cc. of Krebs-Ringer phosphate buffer(pH 7.4) The incubation medium was added C(14)-1-acetate and non-radioactive carrier Na-acetate so as to contain acetate concentration of 50 mg per cent. The worms were allowed to incubate for 5 hours in the Dubnoff metabolic shaking incubator at 38 degrees C. After incubation period, respiratory CO2 samples from central well of incubation flask were analysed for total CO2 production rate and their specific activity of respiratory CO2. The lactate and pyruvate appearance rates were determined by analyzing the lactate and pyruvate concentration in a medium after incubation. The glycogen samples isolated from worms were analyzed for the tissue concentration and their radioactivities in order to determine the turnover rate of glycogen pool. Radioactivities of these series of experiments were counted by an endwindow Geiger-Muller counter as an infinitely thin samples. The quantitative analysis of C(14)-acetate utilized by F. hepatica, E. pancreaticum and P. cervi were compared and discussed in this report. According to these data of the experiment, it is suggested that the fatty acid such as acetate may play a part of their oxidative process into the respiratory CO2 and the synthetic process into glycogen in the above species of trematodes. PMID:12913583

Seo, Byong Seol; Rim, Han Jong; Min, Yong Ok; Rhee, Sang Don; Lee, Tong Hoon; Yun, Myong Soon

1965-12-01

105

Effect of hot water and heat treatment on the apatite-forming ability of titania films formed on titanium metal via anodic oxidation in acetic acid solutions.  

PubMed

Titanium and its alloys have been widely used for orthopedic implants because of their good biocompatibility. We have previously shown that the crystalline titania layers formed on the surface of titanium metal via anodic oxidation can induce apatite formation in simulated body fluid, whereas amorphous titania layers do not possess apatite-forming ability. In this study, hot water and heat treatments were applied to transform the titania layers from an amorphous structure into a crystalline structure after titanium metal had been anodized in acetic acid solution. The apatite-forming ability of titania layers subjected to the above treatments in simulated body fluid was investigated. The XRD and SEM results indicated hot water and/or heat treatment could greatly transform the crystal structure of titania layers from an amorphous structure into anatase, or a mixture of anatase and rutile. The abundance of Ti-OH groups formed by hot water treatment could contribute to apatite formation on the surface of titanium metals, and subsequent heat treatment would enhance the bond strength between the apatite layers and the titanium substrates. Thus, bioactive titanium metals could be prepared via anodic oxidation and subsequent hot water and heat treatment that would be suitable for applications under load-bearing conditions. PMID:18049873

Cui, Xinyu; Kim, Hyun-Min; Kawashita, Masakazu; Wang, Longbao; Xiong, Tianying; Kokubo, Tadashi; Nakamura, Takashi

2008-04-01

106

[Biofiltration without buffering substances in the dialysate].  

PubMed

A new hemodiafiltration technique, acetate free biofiltration (AFB), has been recently introduced in the treatment of chronic uremia. It is performed with a buffer free dialysate and a simultaneous infusion in post-dilution mode of a sodium bicarbonate solution (concentration 145-166 mEq/l; infusion rate 1.2-2 l/h). A polyacrylonitrile hollow fiber AN69 HF 1.2 sqm dialyzer is employed. In acute studies pCO2 remains stable throughout the treatment, as well as pCO2. We have found a significant inverse correlation between delta[HCO3-] pre and post treatment and basal [HCO3-] (r = -0.88; p less than 0.001), with an excellent correction of uremic acidosis, avoiding post dialytic alkalosis. Our long term experience on 6 patients followed up to 31 months, allows us to consider AFB as a feasible and safe treatment, offering a good correction of uremic acidosis and an excellent hemodynamic tolerance. We propose AFB as a competitive technique with respect to bicarbonate hemodialysis, hemodiafiltration and standard biofiltration. PMID:2167517

Quarello, F; Boero, R; Martina, G; Formica, M; Guarena, C; Beltrame, G; Scalzo, B; Forneris, G; Piccoli, G

1990-01-01

107

The influence of physico-chemical properties of TiO 2 on photocatalytic generation of C 1–C 3 hydrocarbons and hydrogen from aqueous solution of acetic acid  

Microsoft Academic Search

The present study was focused on the influence of physico-chemical properties of TiO2 on a photocatalytic generation of useful C1–C3 hydrocarbons (mainly methane) and hydrogen from aqueous solution of acetic acid under N2 atmosphere. The photocatalysts applied in the study were prepared from a crude TiO2 obtained by the sulphate technology. The crude TiO2 was calcined at the temperatures of

Sylwia Mozia; Aleksandra Heciak; Antoni W. Morawski

2011-01-01

108

Effect of royal jelly on experimental colitis induced by acetic acid and alteration of mast cell distribution in the colon of rats  

PubMed Central

This study investigated the effects of royal jelly (RJ) on acetic acid-induced colitis in rats. Twenty adult female Wistar albino rats were divided into four treatment groups of 5 animals each, including a control group (Group I); Group II was treated orally with RJ (150 mg kg?1 body weight); Group III had acetic acid-induced colitis; and Group IV had acetic acid-induced colitis treated orally with RJ (150 mg kg?1 body weight) for 4 weeks. Colitis was induced by intracolonic instillation of 4% acetic acid; the control group received physiological saline (10 mL kg?1). Colon samples were obtained under deep anaesthesia from animals in all groups. Tissues were fixed in 10% formalin neutral buffer solution for 24 h and embedded in paraffin. Six-micrometre-thick sections were stained with Mallory’s triple stain and toluidine blue in 1% aqueous solution at pH 1.0 for 5 min (for Mast Cells). RJ was shown to protect the colonic mucosa against the injurious effect of acetic acid. Colitis (colonic damage) was confirmed histomorphometrically as significant increases in the number of mast cells (MC) and colonic erosions in rats with acetic acid-induced colitis. The RJ treatment significantly decreased the number of MC and reduced the area of colonic erosion in the colon of RJ-treated rats compared with rats with untreated colitis. The results suggest that oral treatment with RJ could be used to treat colitis. PMID:21263740

Karaca, T.; Bayiroglu, F.; Yoruk, M.; Kaya, M.S.; Uslu, S.; Comba, B.; Mis, L.

2010-01-01

109

Effect of royal jelly on experimental colitis Induced by acetic acid and alteration of mast cell distribution in the colon of rats.  

PubMed

This study investigated the effects of royal jelly (RJ) on acetic acid-induced colitis in rats. Twenty adult female Wistar albino rats were divided into four treatment groups of 5 animals each, including a control group (Group I); Group II was treated orally with RJ (150 mg kg(-1) body weight); Group III had acetic acid-induced colitis; and Group IV had acetic acid-induced colitis treated orally with RJ (150 mg kg(-1) body weight) for 4 weeks. Colitis was induced by intracolonic instillation of 4% acetic acid; the control group received physiological saline (10 mL kg(-1)). Colon samples were obtained under deep anaesthesia from animals in all groups. Tissues were fixed in 10% formalin neutral buffer solution for 24 h and embedded in paraffin. Six-micrometre-thick sections were stained with Mallory’s triple stain and toluidine blue in 1% aqueous solution at pH 1.0 for 5 min (for Mast Cells). RJ was shown to protect the colonic mucosa against the injurious effect of acetic acid. Colitis (colonic damage) was confirmed histomorphometrically as significant increases in the number of mast cells (MC) and colonic erosions in rats with acetic acid-induced colitis. The RJ treatment significantly decreased the number of MC and reduced the area of colonic erosion in the colon of RJ-treated rats compared with rats with untreated colitis. The results suggest that oral treatment with RJ could be used to treat colitis. PMID:21263740

Karaca, T; Bayiroglu, F; Yoruk, M; Kaya, M S; Uslu, S; Comba, B; Mis, L

2010-01-01

110

Method for regeneration of electroless nickel plating solution  

DOEpatents

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

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

1997-01-01

111

Method for regeneration of electroless nickel plating solution  

DOEpatents

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

Eisenmann, E.T.

1997-03-11

112

Preparation of ZnFe 2 O 4 Catalysts by a Coprecipitation Method Using Aqueous Buffer Solution and Their Catalytic Activity for Oxidative Dehydrogenation of n Butene to 1,3Butadiene  

Microsoft Academic Search

Zinc ferrite (ZnFe2O4) catalysts were prepared by a co-precipitation method using aqueous buffer solution with different pH (pH = 6?12), and applied\\u000a to the oxidative dehydrogenation of n-butene to 1,3-butadiene. Conversion of n-butene and yield for 1,3-butadiene showed volcano-shaped curves with respect to pH value employed during the co-precipitation\\u000a step. NH3-TPD experiments were conducted to correlate the acid property with the catalytic

Howon Lee; Ji Chul Jung; Heesoo Kim; Young-Min Chung; Tae Jin Kim; Seong Jun Lee; Seung-Hoon Oh; Yong Seung Kim; In Kyu Song

2008-01-01

113

Decreasing Variation in Cook Color of Ground Beef Patties Varying in Myoglobin and pH Using Acetic Acid and Hydrocolloid Solutions  

E-print Network

: Chair of Committee, Rhonda K. Miller Committee Members, Jimmy T. Keeton Peter S. Murano Intercollegiate Faculty Chair, Jimmy T. Keeton December 2009 Major Subject: Food Science and Technology iii ABSTRACT Decreasing Variation in Cook... the use of acetic acid (AA) with xanthan gum (XG) or konjac flour (KF) to reduce variation in cooked color of ground beef patties varying in myoglobin and pH. Beef clods were selected from carcasses of young (48 months, M...

Aldredge, Teresa Lynn

2011-02-22

114

Coprecipitation of Pu(IV) with Fe(III) and Cr(III) hydroxides from nitrate-acetate solutions under hydrothermal conditions simulating deep disposal of liquid radioactive wastes  

Microsoft Academic Search

Precipitation of Fe(III), Cr(III), Ni(II), and Mn(II) from nitrate-acetate solutions and coprecipitation of Pu(IV) with Fe(III)\\u000a and Cr(III) were studied. The degree of precipitation of 80–95% is attained for Fe(III) at 95–200C and pH>0.5–0.6, and for\\u000a Cr(III), at T=95C and pH?4.0 or T=200C and pH?1.0. The phase composition of the precipitates formed by thermal hydrolysis of iron nitrate in model

I. M. Kosareva; M. K. Savushkina; A. B. Yusov; A. M. Fedoseev; O. V. Isakova; V. A. Boldyrev; V. I. Mishkevich

2006-01-01

115

ZINC, MANGANESE AND PHOSPHORUS INTERRELATIONSHIPS AND THEIR EFFECTS ON IRON AND COPPER IN CHELATOR-BUFFERED SOLUTION GROWN RUSSET BURBANK POTATO  

Microsoft Academic Search

Three hydroponic experiments were conducted with Russet Burbank potato to elucidate zinc (Zn) and manganese (Mn) relationships and associated interactions with other nutrients at different levels of phosphorus (P). Except when P was optimal, root Mn concentration was reduced at optimal solution Zn relative to deficient or excessive Zn levels. Shoot Mn generally increased with augmented solution Zn. As solution

Steven A. Barben; Bryan G. Hopkins; Von D. Jolley; Bruce L. Webb; Brandt A. Nichols; Emily A. Buxton

2011-01-01

116

Riparian Buffers for Wildlife Benefits of Riparian Buffers  

E-print Network

Riparian Buffers for Wildlife Benefits of Riparian Buffers Riparian buffers offer many benefits for wildlife; but they also improve water quality for humans. In general, the wider and more diversely planted the buffer, the more likely it is to yield positive benefits. A riparian buffer: Traps sediment. Runoff from

Boyer, Elizabeth W.

117

THE PENETRATION OF BASIC DYE INTO NITELLA AND VALONIA IN THE PRESENCE OF CERTAIN ACIDS, BUFFER MIXTURES, AND SALTS  

PubMed Central

When living cells of Nitella are exposed to an acetate buffer solution until the pH value of the sap is decreased and subsequently placed in a solution of brilliant cresyl blue, the rate of penetration of dye into the vacuole is found to decrease in the majority of cases, and increase in other cases, as compared with the control cells which are transferred to the dye solution directly from tap water. This decrease in the rate is not due to the lowering of the pH value of the solution just outside the cell wall, as a result of diffusion of acetic acid from the cell when cells are removed from the buffer solution and placed in the dye solution, because the relative amount of decrease (as compared with the control) is the same whether the external solution is stirred or not. Such a decrease in the rate may be brought about without a change in the pH value of the sap if the cells are placed in the dye solution after exposure to a phosphate buffer solution in which the pH value of the sap remains normal. The rate of penetration of dye is then found to decrease. The extent of this decrease is the greater the lower the pH value of the solution. It is found that hydrochloric acid and boric acid have no effect while phosphoric acid has an inhibiting effect at pH 4.8 on stirring. Experiments with neutral salt solutions indicate that a direct effect on the cell (decreasing penetration) is due to monovalent base cations, while there is no such effect directly on the dye. It is assumed that the effect of the phosphate and acetate buffer solutions on the cell, decreasing the rate of penetration, is due (1) to the penetration of these acids into the protoplasm as undissociated molecules, which dissociate upon entrance and lower the pH value of the protoplasm or to their action on the surface of the protoplasm, (2) to the effect of base cations on the protoplasm (either at the surface or in the interior), and (3) possibly to the effect of certain anions. In this case the action of the buffer solution is not due to its hydrogen ions. In the case of living cells of Valonia under the same experimental conditions as Nitella it is found that the rate of penetration of dye decreases when the pH value of the sap increases in presence of NH3, and also when the pH value of the sap is decreased in the presence of acetic acid. Such a decrease may be brought about even when the cells are previously exposed to sea water containing HCl, in which the pH value of the sap remains normal. PMID:19872321

Irwin, Marian

1926-01-01

118

Cardiovascular response to hemodialysis: The effects of uremia and dialysate buffer  

Microsoft Academic Search

Cardiovascular response to hemodialysis: The effects of uremia and dialysate buffer. Cardiovascular instability continues to be one of the primary clinical problems in hemodialysis. Acetate buffer in dialysate is one of the factors that may induce hypotension. Since uremia may have a direct effect on the regulation of the cardiovascular system, the present study was designed to investigate the separate

Manuel Jaraba; Alberto Rodríguez-Benot; Rafael Guerrero; Domingo del Castillo; Alejandro Martín-Malo; Mariano Rodríguez; Pedro Aljama

1998-01-01

119

Preparation of vinyl acetate  

DOEpatents

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.

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

1998-01-01

120

Electrooxidation of tigogenin acetate  

Microsoft Academic Search

Electrooxidation of tigogenin acetate afforded two products: 3?-acetoxy-16?-hydroxy-23,24-dinor-5?-cholanoic acid lactone (2) and 20-epitigogenin acetate (3). The structure of the latter compound was confirmed by an X-ray analysis. The tentative mechanism of reaction is proposed.

Jacek W. Morzycki; Yliana López; Jolanta P?oszy?ska; Rosa Santillan; Leszek Siergiejczyk; Andrzej Sobkowiak

2007-01-01

121

The influence of carbon dioxide, bicarbonate and other buffers on the potential of antimony microelectrodes  

Microsoft Academic Search

Summary Antimony microelectrodes were calibrated at 37° C in phosphate buffers, in different bicarbonate solutions at various CO2-partial pressures and in buffers like TRIS, TES, MES and malonic acid. By use of the latter buffers (with exception of malonic acid) the most reliable calibration curves were obtained (“normal values”). The usual calibration in 67 mmol\\/l standard phosphate buffers turned out

P. Quehenberger; S. David

1977-01-01

122

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

Microsoft Academic Search

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

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

1998-01-01

123

UV-ozone-treated MoO3 as the hole-collecting buffer layer for high-efficiency solution-processed SQ:PC71BM photovoltaic devices  

NASA Astrophysics Data System (ADS)

The enhanced performance of a squaraine compound, with 2,4-bis[4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl] squaraine as the donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor, in solution-processed organic photovoltaic devices is obtained by using UV-ozone-treated MoO3 as the hole-collecting buffer layer. The optimized thickness of the MoO3 layer is 8 nm, at which the device shows the best power conversion efficiency (PCE) among all devices, resulting from a balance of optical absorption and charge transport. After being treated by UV-ozone for 10 min, the transmittance of the MoO3 film is almost unchanged. Atomic force microscopy results show that the treated surface morphology is improved. A high PCE of 3.99% under AM 1.5 G illumination (100 mW/cm2) is obtained.

Yang, Qian-Qian; Yang, Dao-Bin; Zhao, Su-Ling; Huang, Yan; Xu, Zheng; Gong, Wei; Fan, Xing; Liu, Zhi-Fang; Huang, Qing-Yu; Xu, Xu-Rong

2014-03-01

124

The Acetate Switch  

PubMed Central

To succeed, many cells must alternate between life-styles that permit rapid growth in the presence of abundant nutrients and ones that enhance survival in the absence of those nutrients. One such change in life-style, the “acetate switch,” occurs as cells deplete their environment of acetate-producing carbon sources and begin to rely on their ability to scavenge for acetate. This review explains why, when, and how cells excrete or dissimilate acetate. The central components of the “switch” (phosphotransacetylase [PTA], acetate kinase [ACK], and AMP-forming acetyl coenzyme A synthetase [AMP-ACS]) and the behavior of cells that lack these components are introduced. Acetyl phosphate (acetyl?P), the high-energy intermediate of acetate dissimilation, is discussed, and conditions that influence its intracellular concentration are described. Evidence is provided that acetyl?P influences cellular processes from organelle biogenesis to cell cycle regulation and from biofilm development to pathogenesis. The merits of each mechanism proposed to explain the interaction of acetyl?P with two-component signal transduction pathways are addressed. A short list of enzymes that generate acetyl?P by PTA-ACKA-independent mechanisms is introduced and discussed briefly. Attention is then directed to the mechanisms used by cells to “flip the switch,” the induction and activation of the acetate-scavenging AMP-ACS. First, evidence is presented that nucleoid proteins orchestrate a progression of distinct nucleoprotein complexes to ensure proper transcription of its gene. Next, the way in which cells regulate AMP-ACS activity through reversible acetylation is described. Finally, the “acetate switch” as it exists in selected eubacteria, archaea, and eukaryotes, including humans, is described. PMID:15755952

Wolfe, Alan J.

2005-01-01

125

Growth and Nutrient Uptake by Barley (Hordeum vulgare L. cv Herta): Studies Using an N-(2-Hydroxyethyl)ethylenedinitrilotriacetic Acid-Buffered Nutrient Solution Technique (II. Role of Zinc in the Uptake and Root Leakage of Mineral Nutrients).  

PubMed Central

Barley seedlings (Hordeum vulgare L. cv Herta) were grown in N-(2-hydroxyethyl)ethylenedinitrilotriacetic acid-buffered nutrient solutions with or without adequate Zn supplies. Fifteen-d-old Zn-deficient seedlings contained higher concentrations of Mn, Ca, Mg, and P in their shoots and more Fe, Mn, Cu, K, Ca, and P in their roots than did similar Zn-adequate seedlings, confirming results reported in our companion study (W.A. Norvell and R.M. Welch [1993] Plant Physiol 101: 619-625). Zn-deficient roots leaked greater quantities of K, Mn, Cu, and Cl than did roots supplied adequately with Zn; they also leaked significant amounts of Zn even though the seedlings were not supplied Zn during growth. Calculated uptake rates of P, Mn, and Na were sharply reduced, but uptake rates of K and Mg were stimulated by increasing the Zn2+ activity in nutrient solutions. Intact roots of Zn-deficient seedlings contained lower concentrations of 5,5[prime] -dithio-bis(2-nitrobenzoic acid) reactive sulfhydryl groups in comparison to Zn-adequate roots. Apparently, Zn is required for the uptake and retention of several mineral nutrients by roots, possibly by playing a protective role in preventing the oxidation of sulfhydryl groups to disulfides in root-cell plasma membrane proteins involved in ion channel-gating phenomena. PMID:12231718

Welch, R. M.; Norvell, W. A.

1993-01-01

126

Aggregation of aqueous lysozyme solutions followed by dynamic light scattering and 1H NMR spectroscopy  

Microsoft Academic Search

In the presented work, we followed our previous calorimetric investigation [J. Pozna?ski, M. Wszelaka-Rylik, W. Zielenkiewicz, Termochim. Acta 409 (2004) 25–32], analyzing the kinetics of NaCl-induced lysozyme aggregation. The aggregates' size distribution was monitored independently by dynamic light scattering (DLS) and nuclear magnetic resonance (NMR). Experiments were conducted for 2.1 mM lysozyme solution in acetate buffer, pH=4.25, in the NaCl

Jaros?aw Pozna?ski; J?drzej Szyma?ski; Teresa Basi?ska; Stanis?aw S?omkowski; Wojciech Zielenkiewicz

2005-01-01

127

Selective perborate signaling by deprotection of fluorescein and resorufin acetates.  

PubMed

The acetate derivatives of fluorescein and resorufin exhibited a prominent turn-on type signaling behavior toward BO(3)(-) ions over other common anions. Signaling is based on the selective deprotection of acetate groups by perborate, which resulted in significant chromogenic and fluorogenic signaling. Compound 1 also exhibited a pronounced perborate selectivity over other commonly used oxidants in 90% aqueous acetonitrile solution. PMID:20222739

Choi, Myung Gil; Cha, Sunyoung; Park, Ji Eun; Lee, Haekyung; Jeon, Hye Lim; Chang, Suk-Kyu

2010-04-01

128

Virginia Tech - Buffer Pool  

NSDL National Science Digital Library

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

Shaffer, Cliff; Sariaya, Purvi

129

Effects of Buffer Loading for Electrospray Ionization Mass Spectrometry of a Noncovalent Protein Complex that Requires High Concentrations of Essential Salts  

PubMed Central

Electrospray ionization (ESI) mass spectrometry (MS) is a powerful method for analyzing the active forms of macromolecular complexes of biomolecules. However, these solutions often contain high concentrations of salts and/or detergents that adversely effect ESI performance by making ion formation less reproducible, causing severe adduction or ion suppression. Many methods for separating complexes from nonvolatile additives are routinely used with ESI-MS, but these methods may not be appropriate for complexes that require such stabilizers for activity. Here, the effects of buffer loading using concentrations of ammonium acetate ranging from 0.22 to 1.41 M on the ESI mass spectra of a solution containing a domain truncation mutant of a ?54 activator from Aquifex aeolicus were studied. This 44.9 kDa protein requires the presence of millimolar concentrations of Mg2+, BeF3?, and ADP, (at ?60 °C) to assemble into an active homo-hexamer. Addition of ammonium acetate can improve signal stability and reproducibility, and can significantly lower adduction and background signals. However, at higher concentrations, the relative ion abundance of the hexamer is diminished, while that of the constituent monomer is enhanced. These results are consistent with loss of enzymatic activity as measured by ATP hydrolysis and indicate that the high concentration of ammonium acetate interferes with assembly of the hexamer. This shows that buffer loading with ammonium acetate is effective for obtaining ESI signal for complexes that require high concentrations of essential salts, but can interfere with formation of, and/or destabilize complexes by disrupting crucial electrostatic interactions at high concentration. PMID:20226685

Sterling, Harry J.; Batchelor, Joseph D.; Wemmer, David E.; Williams, Evan R.

2010-01-01

130

Rapid determination of tamsulosin in human plasma by high-performance liquid chromatography using extraction with butyl acetate  

Microsoft Academic Search

A high-performance liquid chromatographic method with fluorescence detection for the determination of tamsulosin in human plasma is reported. The sample preparation involved liquid–liquid extraction of tamsulosin from alkalised plasma with butyl acetate and back-extraction of the drug to the phosphate buffer (pH 2). Butyl acetate is preferable to more commonly used ethyl acetate because of its much lower solubility in

J. Macek; J. Klíma; P. Ptá?ek

2004-01-01

131

Acid Rain Experiments: Soil Buffering  

NSDL National Science Digital Library

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

132

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

PubMed

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

Chang, E; Lee, T M

2002-07-01

133

An electrochemical quartz crystal impedance study on cystine precipitation onto an Au electrode surface during cysteine oxidation in aqueous solution  

Microsoft Academic Search

Electrochemical quartz crystal impedance studies on l-cysteine oxidation in aqueous solutions were conducted. The precipitation of electrogenerated species on the Au electrode surface was found in acetic and phosphate buffers. Changes in the equivalent circuit parameters, resonant frequencies and half peak width of the conductance spectra (?fG1\\/2) obtained simultaneously during electrochemical experiments were discussed. Significant changes in the motional resistance

Qingji Xie; Youyu Zhang; Yu Yuan; Yanghui Guo; Xiangjun Wang; Shouzhuo Yao

2000-01-01

134

Growth and characterization of pure and doped cadmium thiourea acetate single crystals  

Microsoft Academic Search

Pure and doped (zinc acetate, N-methylurea and glycine) cadmium thiourea acetate single crystals were grown by slow evaporation solution growth method. The UV–visible, high-resolution X-ray diffraction and dielectric studies show the enhancement in the crystalline perfection of the glycine-doped cadmium thiourea acetate. The zinc acetate does not have significant effect on the structural and chemical properties, but has some effect

S. Shahil Kirupavathy; S. Stella Mary; P. Mythili; R. Gopalakrishnan

2008-01-01

135

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

Microsoft Academic Search

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

A. J. Ricci; R. Fettiplace

1998-01-01

136

Mechanisms of buffer therapy resistance  

PubMed Central

Many studies have shown that the acidity of solid tumors contributes to local invasion and metastasis. Oral pH buffers can specifically neutralize the acidic pH of tumors and reduce the incidence of local invasion and metastatic formation in multiple murine models. However, this effect is not universal as we have previously observed that metastasis is not inhibited by buffers in some tumor models, regardless of buffer used. B16-F10 (murine melanoma), LL/2 (murine lung) and HCT116 (human colon) tumors are resistant to treatment with lysine buffer therapy, whereas metastasis is potently inhibited by lysine buffers in MDA-MB-231 (human breast) and PC3M (human prostate) tumors. In the current work, we confirmed that sensitive cells utilized a pH-dependent mechanism for successful metastasis supported by a highly glycolytic phenotype that acidifies the local tumor microenvironment resulting in morphological changes. In contrast, buffer-resistant cell lines exhibited a pH-independent metastatic mechanism involving constitutive secretion of matrix degrading proteases without elevated glycolysis. These results have identified two distinct mechanisms of experimental metastasis, one of which is pH-dependent (buffer therapy sensitive cells) and one which is pH-independent (buffer therapy resistant cells). Further characterization of these models has potential for therapeutic benefit. PMID:24862761

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

2014-01-01

137

Memory access buffering in multiprocessors  

Microsoft Academic Search

In highly-pipelined machines, instructions and data are prefetched and buffered in both the processor and the cache. This is done to reduce the average memory access latency and to take advantage of memory interleaving. Lock-up free caches are designed to avoid processor blocking on a cache miss. Write buffers are often included in a pipelined machine to avoid processor waiting

Michel Dubois; Christoph Scheurich; Faye A. Briggs

1986-01-01

138

Ring Buffered Network Bus  

NASA Technical Reports Server (NTRS)

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.

1997-01-01

139

Acetic acid bacteria in oenology  

Microsoft Academic Search

Acetic acid bacteria have always been considered the bad mi- croorganisms of oenology; responsible for wine spoiling (vine- gary taint). The taxonomy and our knowledge of the metabo- lism of acetic acid bacteria are rapidly evolving, especially as new molecular biology techniques are applied to this fastidious group of microorganisms, which are still rather difficult to work with. The dramatic

A. Mas; M. J. Torija; A. González; M. Poblet; J. M. Guillamón

140

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

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Buffered penicillin powder, penicillin powder with buffered aqueous diluent. 520...FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered...

2011-04-01

141

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

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Buffered penicillin powder, penicillin powder with buffered aqueous diluent. 520...FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered...

2010-04-01

142

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Buffered penicillin powder, penicillin powder with buffered aqueous diluent. 520...FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered...

2012-04-01

143

Growth and characterization of pure and doped cadmium thiourea acetate single crystals  

NASA Astrophysics Data System (ADS)

Pure and doped (zinc acetate, N-methylurea and glycine) cadmium thiourea acetate single crystals were grown by slow evaporation solution growth method. The UV-visible, high-resolution X-ray diffraction and dielectric studies show the enhancement in the crystalline perfection of the glycine-doped cadmium thiourea acetate. The zinc acetate does not have significant effect on the structural and chemical properties, but has some effect on the electrical properties. However, the addition of N-methylurea activates the cadmium thiourea acetate ions, resulting in the decrease of the space charge polarization and increase in intrinsic defects.

Shahil Kirupavathy, S.; Stella Mary, S.; Mythili, P.; Gopalakrishnan, R.

2008-05-01

144

In vitro methane and methyl coenzyme M formation from acetate: evidence that acetyl-CoA is the required intermediate activated form of acetate.  

PubMed

Buffer-soluble extracts of acetate-grown Methanosarcina barkeri catalyzed methanogenesis from acetate in the presence of hydrogen and ATP. The rates of methane formation from either acetate plus ATP, or acetylphosphate without ATP added, were approximately doubled by the addition of coenzyme A (CoA). In vitro methyl group transfer from [2-14C]acetate to form [14CH3]methyl coenzyme M (14CH3S-CoM) was monitored by causing the accumulation of 14CH3S-CoM (14CH3-SCH2CH2SO3-) in the presence of 2-bromoethanesulfonate. The rate of 14CH3S-CoM formation was increased 2.5-fold by 0.2 mM CoA. PMID:3115259

Grahame, D A; Stadtman, T C

1987-08-31

145

Comparative study of uptake and cellular distribution of Hg²°³-labeled phenyl-mercuric acetate and mercuric acetate by pea roots  

Microsoft Academic Search

Uptake and cellular distribution of mercury²°³ from dilute mercuric acetate of phenylmercuric acetate solutions by excised pea roots (Pisum sativum) have been investigated. The time course of uptake showed that the amount of mercury uptake was increased with the time of incubation, and was similar for inorganic mercury or phenylmercuric acetate. The trend of mercury²°³ incorporation into cellular components from

A. V. Rao; E. Fallin; S. C. Fang

1966-01-01

146

New approach for the production of cellulose acetate: acetylation of mechanical pulp with subsequent isolation of cellulose acetate by differential solubility  

Microsoft Academic Search

A heretofore uninvestigated approach to the production of cellulose acetate is the acetylation of mechanical pulp with subsequent isolation of the cellulose derivative by differential solubility. The mechanical pulp is produced by refining aspen wood chips in a disc-refiner. Two conventional acetylation techniques, the fibrous and solution process, are employed to acetylate all components of the pulp. The cellulose acetate

Barkalow

1987-01-01

147

Buffer Gas Acquisition and Storage  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

148

Preclinical safety of anecortave acetate.  

PubMed

A number of preclinical safety pharmacology and toxicity studies have been performed on the angiostatic cortisene anecortave acetate in various species and using different routes of administration (oral, intravenous, subcutaneous, topical ocular, intraocular injection, posterior juxtascleral) and a wide range of doses (0-1,000 mg/kg). Anecortave acetate did not interact with a broad panel of pharmacological receptors and had no apparent pharmacological effects on major organ systems including the central nervous, gastrointestinal, renal, cardiovascular, and respiratory systems. Oral, topical ocular, and posterior juxtascleral administration of anecortave acetate had no significant ocular or systemic side effects or toxicity. In addition, there was no significant carcinogenic or reproductive/developmental toxicity associated with anecortave acetate in genotoxicity, carcinogenicity, and reproductive toxicity studies. PMID:17240255

Heaton, Jim; Kastner, Philip; Hackett, Robert

2007-01-01

149

New reinfusate composition in high UF haemodiafiltration: electrolyte solution combined with bicarbonate.  

PubMed

When high-permeability membranes are employed, high UF should be used in order to obtain optimal uraemic toxin removal and to avoid backfiltration. A high UF requires the infusion of an electrolyte solution including Ca2+ and Mg2+ which cannot be associated with bicarbonate in prepackaged solutions because of the risk of precipitation; therefore acetate or lactate are used as buffers. This study evaluated whether bicarbonate can be infused together with an electrolyte solution in high UF HDF, and if so, the clinical advantages that could be obtained by substituting acetate with bicarbonate in the reinfusate. In 12 patients on postdilutional high UF (121 +/- 10 ml/min) HDF (Qb 400, Qd 500 ml/min, dialysate containing Na, 141 +/- 2; K, 2.5; Ca, 3.5; Mg, 0.7; Cl, 111 +/- 2; acetate, 3; bicarbonate, 34 mEq/l; TMP 400 mmHg), an acid bag (Na, 128; K, 4; Ca, 7; Mg, 2; Cl, 141; acetate, 8 mEq/l), and a basic bag (Na, 150; HCO3, 80; Cl, 70 mEq/l), each containing 2 litres, were simultaneously infused through a Y connection. The final composition of reinfusate at the drip-chamber, combined with the above dialysate, allowed a negative intradialytic mass balance for Na, K, Mg and a positive one for Ca, acetate, to maintain prepostdialytic plasma values of these ions as well as bicarbonate close to normal limits. Furthermore, in five high-risk patients, clinical data were evaluated on high UF HDF, infusing a solution containing either acetate or bicarbonate, and an improvement of vascular stability was observed with the bicarbonate reinfusate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8381936

Gonella, M; Calabrese, G; Pratesi, G; Baldin, C; Mazzotta, A; Vagelli, G

1993-01-01

150

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

NASA Astrophysics Data System (ADS)

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

Liu, Xiangxiang; Wan, Yiqun

2013-07-01

151

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

Microsoft Academic Search

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

Justine Criquet; Nathalie Karpel Vel Leitner

2009-01-01

152

[Comparison of different buffer systems for separation of 15 nucleosides by capillary electrophoresis].  

PubMed

The most suitable background electrolytes (BGEs) for simultaneous separation of 15 nucleosides by different modes of capillary electrophoresis (CE) were obtained. Various modes of CE were performed including capillary zone electrophoresis (CZE), capillary electrophoresis-electrospray ionization-time of flight mass spectrometry (CE-ESI-TOF/MS) and micellar electrokinetic chromatography (MEKC). The electrolyte buffers using sodium tetraborate decahydrate, disodium hydrogen phosphate, sodium acetate, sodium bicarbonate, ammonium acetate or 1, 2-diamino-ethane (DEA) were tested, and the best of them were systematically optimized. In CZE mode, the nucleosides could not be separated completely with sodium tetraborate decahydrate or disodium hydrogen phosphate as BGEs, demonstrating the limited applicability of the two buffer systems for complex samples. However, with 300 mmol/L DEA (containing 2% acetone) as BGE, 15 nucleosides could be separated with good resolution and peak shape, which proved that the DEA buffer was most suitable in CZE. The best buffer system in MEKC mode was 25 mmol/L disodium hydrogen phosphate with 70 mmol/L sodium dodecyl sulfate (SDS), and it was successfully applied for the separation of the nucleosides in Chinese Anthopleura lanthogrammica Berkly. The optimum buffer system for CE-ESI-TOF/MS analysis was 20 mmol/L ammonium acetate (pH 10.0). In the positive ion mode, the MS signals of each compound were better than those in the literature using DEA as BGE. The results of this study demonstrated the applicability of different buffer systems for the simultaneous separation of 15 nucleosides, and were helpful for the development of CE method in complex sample separation. PMID:22032157

Shi, Qian; Chen, Junhui; Li, Xin; Cao, Wei; Zheng, Li; Zang, Jiaye; Wang, Xiaoru

2011-06-01

153

Chapter 6. Solutions Composition of Solutions  

E-print Network

the vapor pressure of diethyl ether above the resulting solution. #12;#12;Boiling point elevation · When 2, the boiling point of the cylcohexane is raised by 0.41 C. Calculate Kb for cyclohexane. #12;#12;#12;OsmoticChapter 6. Solutions #12;Composition of Solutions · A solution of acetic acid and water contains

Ihee, Hyotcherl

154

Lactate and acetate production in Listeria innocua.  

PubMed

Listeria innocua NCTC 11289 was grown aerobically in continuous culture in defined media at 30 degrees C. Both acetate and lactate were produced, the proportion of acetate decreased with increasing dilution rate. Enzymatic analysis showed lactate dehydrogenase was activated 10-fold by fructose-1, 6-bisphosphate. The presence of phosphate acetyltransferase and acetate kinase but not pyruvate oxidase was detected, suggesting the sequential action of phosphate acetyltransferase and acetate kinase to produce acetate from acetyl CoA via acetylphosphate. PMID:8987454

Kelly, A F; Patchett, R A

1996-08-01

155

Experimental sea water buffers for use as secondary pH standards  

E-print Network

water test solutions differing in ionic strength and com- position. Sea water buffered with the weak base tris(hydroxy- methyl)aminomethane and its hydrochloride salt is proposed as secondary pH standards for the calibration of marine pH measuring... of this thesis to increase the readability of sea water pH measuring systems with the aid of a sea water buffer as the calibrating solution. The pH of sea water solutions buffered with the weak base tris- (hydroxymethyl)sminomethane and its hydrochloride...

Smith, William Hamilton, Jr

1962-01-01

156

Evidence for an essential arginine residue at the active site of Escherichia coli acetate kinase.  

PubMed

Escherichia coli acetate kinase (ATP: acetate phosphotransferase, EC 2.7.2.1.) was inactivated in the presence of either 2,3-butanedione in borate buffer or phenylglyoxal in triethanolamine buffer. When incubated with 9.4 mM phenylglyoxal or 5.1 mM butanedione, the enzyme lost its activity with an apparent rate constant of inactivation of 0.079 min-1, respectively. The loss of enzymatic activity was concomitant with the loss of an arginine residue per active site. Phosphorylated substrates of acetate kinase, ATP, ADP and acetylphosphate as well as AMP markedly decreased the rate of inactivation by both phenylglyoxal and butanedione. Acetate neither provided any protection nor affected the protection rendered by the adenine nucleotides. However, it interfered with the protection afforded by acetylphosphate. These data suggest that an arginine residue is located at the active site of acetate kinase and is essential for its catalytic activity, probably as a binding site for the negatively charged phosphate group of the substrates. PMID:6268170

Wong, S S; Wong, L J

1981-07-24

157

Microbiological preservation of cucumbers for bulk storage by the use of acetic acid and food preservatives  

Technology Transfer Automated Retrieval System (TEKTRAN)

Microbial growth did not occur when cucumbers were preserved without a thermal process by storage in solutions containing acetic acid, sodium benzoate, and calcium chloride to maintain tissue firmness. The concentrations of acetic acid and sodium benzoate required to assure preservation were low en...

158

Journal of Membrane Science 205 (2002) 1121 Macrovoid pore formation in dry-cast cellulose acetate  

E-print Network

Journal of Membrane Science 205 (2002) 11­21 Macrovoid pore formation in dry-cast cellulose acetate of macrovoid (MV) pores formed during the dry-casting of cellulose acetate (CA)/acetone/water casting solutions were cast in low-gravity (low-g) (KC-135) and normal-gravity (1-g) (ground-based control) from CA

Shvartsman, Stanislav "Stas"

159

CRYSTAL AND MOLECULAR STRUCTURE OF 6,6´-DIMETHOXY-GOSSYPOL:ACETIC ACID (1:1)  

Technology Transfer Automated Retrieval System (TEKTRAN)

By crystallization from dilute solutions of acetic acid (2-4%) in diethyl ether, acetone, or methyl ethyl ketone, 6,6´-dimethoxy-gossypol forms an inclusion complex with acetic acid in a one-to-one molar ratio. The compound crystallizes in the triclinic P1bar1¯space group and has unit cell dimensio...

160

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

ERIC Educational Resources Information Center

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)

Lombardo, Anthony

1982-01-01

161

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

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

162

Acetate fuels the cancer engine.  

PubMed

Cancer cells have distinctive nutrient demands to fuel growth and proliferation, including the disproportionate use of glucose, glutamine, and fatty acids. Comerford et al. and Mashimo et al. now demonstrate that several types of cancer are avid consumers of acetate, which facilitates macromolecular biosynthesis and histone modification. PMID:25525870

Lyssiotis, Costas A; Cantley, Lewis C

2014-12-18

163

Desmopressin Acetate in Intracranial Haemorrhage  

PubMed Central

Introduction. The secondary increase in the size of intracranial haematomas as a result of spontaneous haemorrhage or trauma is of particular relevance in the event of prior intake of platelet aggregation inhibitors. We describe the effect of desmopressin acetate as a means of temporarily stabilising the platelet function. Patients and Methods. The platelet function was analysed in 10 patients who had received single (N = 4) or multiple (N = 6) doses of acetylsalicylic acid and 3 patients (control group) who had not taken acetylsalicylic acid. All subjects had suffered intracranial haemorrhage. Analysis was performed before, half an hour and three hours after administration of desmopressin acetate. Statistical analysis was performed by applying a level of significance of P ? 0.05. Results. (1) Platelet function returned to normal 30 minutes after administration of desmopressin acetate. (2) The platelet function worsened again after three hours. (3) There were no complications related to electrolytes or fluid balance. Conclusion. Desmopressin acetate can stabilise the platelet function in neurosurgical patients who have received acetylsalicylic acid prior to surgery without causing transfusion-related side effects or a loss of time. The effect is, however, limited and influenced by the frequency of drug intake. Further controls are needed in neurosurgical patients. PMID:25610644

Kapapa, Thomas; Röhrer, Stefan; Struve, Sabine; Petscher, Matthias; König, Ralph; Wirtz, Christian Rainer; Woischneck, Dieter

2014-01-01

164

Stacked Switched Capacitor Energy Buffer Architecture  

E-print Network

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

Chen, Minjie

165

Stacked switched capacitor energy buffer architecture  

E-print Network

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

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

2012-01-01

166

The influence of carbon dioxide, bicarbonate and other buffers on the potential of antimony microelectrodes.  

PubMed

Antimony microelectrodes were calibrated at 37 degrees C in phosphate buffers, in different bicarbonate solutions at various CO2-partial pressures and in buffers like TRIS1, TES2, MES3 and malonic acid. By use of the latter buffers (with exception of malonic acid) the most reliable calibration curves were obtained ("normal values"). The usual calibration in 67 mmol/l standard phosphate buffers turned out to be unacceptable because the obtained mV-values were too high (negative) in comparison to all other buffers. Different calibration curves resulted from the use of pure bicarbonate solution whether the pH-values were changed by variation of pCO2 or of the bicarbonate concentration. Low bicarbonate concentrations in combination with low pCO2 gave mV-values which were too low relative to the other buffers. Both the increase of pCO2 as well as of the bicarbonate concentration caused a shift of the potential of the antimony electrodes toward "normal values". In solutions containing other buffers the influence of bicarbonate and pCO2 became negligible with increasing buffer concentration. Decreasing oxygen partial pressure was found to cause an increase of the potential of the antimony electrodes. The influence of liquid junction potentials at the reference electrode is discussed. PMID:558586

Quehenberger, P

1977-03-11

167

Spectrophotometric flow-injection analysis of the total base number in lubricants by using acid–base buffers  

Microsoft Academic Search

A spectrophotometric FIA method for the determination of the total base number (TBN) in a lubricant was proposed, which involved using an acid–base buffer solution prepared with a nonaqueous solvent. This method is based on measurements of the absorbance change of an indicator contained in the acid–base buffer solution, which is generated due to a neutralization reaction of base in

Keiko Jyonosono; Toshihiko Imato; Noriyuki Imazumi; Masayuki Nakanishi; Jun-ichi Yagi

2001-01-01

168

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...

169

Doped LZO buffer layers for laminated conductors  

DOEpatents

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

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

2010-03-23

170

Optimal Offline TCP Sender Buffer Management Strategy  

Microsoft Academic Search

The transmission control protocol (TCP) uses a sliding window in order to enforce flow control. The receiver advertises its available buffer space to the sender, which cannot transmit more data than the advertised space. Transmitted data is first copied from application buffers into TCP buffers and from there it is sent through the network. In this paper we propose a

Mugurel Ionut Andreica; Nicolae Tapus

2008-01-01

171

Experimental study of the hydrothermal reactivity of organic acids and acid anions: II. Acetic acid, acetate, and valeric acid  

NASA Astrophysics Data System (ADS)

Organic acids and acid anions occur in substantial concentrations in many aqueous geologic fluids and are thought to take part in a variety of geochemical processes ranging from the transport of metals in ore-forming fluids to the formation of natural gas to serving as a metabolic energy source for microbes in subsurface habitats. The widespread occurrence of organic acids and their potential role in diverse geologic processes has led to numerous experimental studies of their thermal stability, yet there remain substantial gaps in our knowledge of the factors that control the rates and reaction pathways for the decomposition of these compounds under geologic conditions. In order to address some of these uncertainties, a series of laboratory experiments were conducted to examine the behavior of organic acids and acid anions under hydrothermal conditions in the presence of minerals. Reported here are results of experiments where aqueous solutions of acetic acid, sodium acetate, or valeric acid ( n-pentanoic acid) were heated at 325°C, 350 bars in the presence of the mineral assemblages hematite + magnetite + pyrite, pyrite + pyrrhotite + magnetite, and hematite + magnetite. The results indicate that aqueous acetic acid and acetate decompose by a combination of two reaction pathways: decarboxylation and oxidation. Both reactions are promoted by minerals, with hematite catalyzing the oxidation reaction while magnetite catalyzes decarboxylation. The oxidation reaction is much faster, so that oxidation dominates the decomposition of acetic acid and acetate when hematite is present. In contrast to previous reports that acetate decomposed more slowly than acetic acid, we found that acetate decomposed at slightly faster rates than the acid in the presence of minerals. Although longer-chain monocarboxylic acids are generally thought to decompose by decarboxylation, valeric acid appeared to decompose primarily by "deformylation" to 1-butene plus formic acid. Subsequent decomposition of 1-butene and formic acid generated a variety of short-chain (?C 4) hydrocarbons and moncarboxylic acids as well as CO 2. Valeric acid decomposition proceeded more rapidly (by a factor of 2) in the presence of hematite-magnetite-pyrite than with the other mineral assemblages, with the greater reaction rate apparently attributable to the effects of fluid chemistry. Valeric acid was observed to decompose at a substantially faster rate than acetic acid under similar conditions. The results suggest that decomposition of aqueous monocarboxylic acids may make a significant contribution to the conversion of petroleum to light hydrocarbons in natural gas and thermal fluids.

McCollom, Thomas M.; Seewald, Jeffrey S.

2003-10-01

172

Solutions  

NASA Astrophysics Data System (ADS)

Type-VIII Ba8Ga16Sn30 polycrystalline clathrates were grown vertically downwards from Ba8Ga16Sn50 solution at furnace temperatures between 500°C and 800°C with an ampoule velocity of 0.36 cm/h. The microstructure, composition, crystal structure, and thermoelectric properties of crystals were investigated. Polycrystalline samples in which Ba8Ga16Sn30 grains were wetted by an Sn-rich phase were prepared. In general, grain size increases along the direction of growth. It was found that the sample grown at 650°C had the largest grains. Smaller grains were observed for samples grown at lower temperatures, as a result of higher rate of nucleation, because of higher undercooling at the solid-liquid interface caused by the lower thermal gradient in the liquid. However, at furnace temperatures higher than 650°C enhanced convection in the solution at higher temperature gradients and wetting phenomena may cause instability of the solid-liquid interface and solid nuclei may flow into the liquid to become new nucleation sites. This explains the decrease of grain size at higher furnace temperatures. The optimum ZT and power factor of the undoped Ba8Ga16Sn30 clathrate prepared by the vertical Bridgman method in this study were, respectively, 0.8 and 11.4 ?W/cmK2 at 200°C; the Seebeck coefficient was -260 ?V/K.

Hong, Qin-Gang; Chang, Li-Shin; Hsieh, Huey-Lin

2014-06-01

173

Joint Buffer & Server Allocation Van Woensel et al. Buffer and Server Allocation in General  

E-print Network

Joint Buffer & Server Allocation Van Woensel et al. Buffer and Server Allocation in General Multi-Server Abstract -- This paper deals with the joint optimization of the number of buffers and servers, an important issue since buffers and servers represent a significant amount of investment for many companies

Cruz, Frederico

174

Buffer effects on electric signals of light-excited bacteriorhodopsin.  

PubMed Central

Buffers change the electric signals of light-excited bacteriorhodopsin molecules in purple membrane if their concentration and the pH of the low-salt solution are properly selected. "Positive" buffers produce a positive component, and "negative" buffers a negative component in addition to the signals due to proton pumping. Measurement of the buffer effects in the presence of glycyl-glycine or bis-tris propane revealed an increase of approximately 2 and a change of sign and a decrease to approximately -0.5 in the translocated charge in these cases, respectively. These factors do not depend on temperature. The Arrhenius parameters established from the evaluation of the kinetics indicate activation enthalpies of 35-40 kJ/mol and negative activation entropies for the additional signals. These values agree with those found by surface-bound pH-sensitive probes in the search of the timing of proton release and uptake. The electric signals were also measured in the case of D(2)O solutions with similar results, except for the increased lifetimes. We offer a unified explanation for the data obtained with surface-bound probes and electric signals based on the clusters at extracellular and cytoplasmic sites of bacteriorhodopsin participating in proton release and uptake. PMID:10827993

Tóth-Boconádi, R; Dér, A; Keszthelyi, L

2000-01-01

175

Synthesis and regeneration of lead (IV) acetate  

SciTech Connect

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

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

1996-11-01

176

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

177

21 CFR 73.2396 - Lead acetate.  

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

2014-04-01

178

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

179

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

180

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

181

Acetate kinase activity in mycoplasmas.  

PubMed

Acetate kinase activity was assayed in 13 mycoplasmas. Nine species exhibited the enzymic activity in the direction of either synthesis of acetylphosphate or adenosine triphosphate. On the other hand Mycoplasma orale, Mycoplasma arthritidis, Ureaplasma urealyticum (10 serotypes), and two strains of Anaeroplasma species exhibited only minimal levels of the enzymic activity. In these four species, the enzyme does not seem to play a key role in adenosine triphosphate formation. PMID:6263869

Muhlrad, A; Peleg, I; Robertson, J A; Robinson, I M; Kahane, I

1981-07-01

182

Reactivity of the Quinone Methide of Butylated hydroxytoluene in Solution  

E-print Network

of QM with water at various pH values and in the presence of sodium chloride and phosphate, acetate, and TAPS buffers. The presence of HCl, HClO4, NaOH, NaCl, and phosphate buffers resulted in simple first order kinetics for disappearance of QM...

Willcockson, Maren Gulsrud

2011-08-31

183

Growth and Nutrient Uptake by Barley (Hordeum vulgare 1. cv Herta): Studies Using an N-(2-Hydroxyethyl)ethylenedinitrilotriacetic Acid-Buffered Nutrient Solution Technique 1. Zinc lon Requirements  

Microsoft Academic Search

Controlling micronutrient cation activities in nutrient me- measured. ~i~~~~~~i~~~ metals were included as chelates of dia at the extremelY loW levels commonly found in sOil HEDTA. Zn treatments consisted of five levels of added Zn- solutions is an important but difficult objective. Until re- HEDTA from 0.1 to 20 pM. ~~~h of the solutions cently, this option was limited to

Wendell A. Norvell; Ross M. Welch

184

Transports of acetate and haloacetate in Burkholderia species MBA4 are operated by distinct systems  

PubMed Central

Background Acetate is a commonly used substrate for biosynthesis while monochloroacetate is a structurally similar compound but toxic and inhibits cell metabolism by blocking the citric acid cycle. In Burkholderia species MBA4 haloacetate was utilized as a carbon and energy source for growth. The degradation of haloacid was mediated by the production of an inducible dehalogenase. Recent studies have identified the presence of a concomitantly induced haloacetate-uptake activity in MBA4. This uptake activity has also been found to transport acetate. Since acetate transporters are commonly found in bacteria it is likely that haloacetate was transported by such a system in MBA4. Results The haloacetate-uptake activity of MBA4 was found to be induced by monochloroacetate (MCA) and monobromoacetate (MBA). While the acetate-uptake activity was also induced by MCA and MBA, other alkanoates: acetate, propionate and 2-monochloropropionate (2MCPA) were also inducers. Competing solute analysis showed that acetate and propionate interrupted the acetate- and MCA- induced acetate-uptake activities. While MCA, MBA, 2MCPA, and butyrate have no effect on acetate uptake they could significantly quenched the MCA-induced MCA-uptake activity. Transmembrane electrochemical potential was shown to be a driving force for both acetate- and MCA- transport systems. Conclusions Here we showed that acetate- and MCA- uptake in Burkholderia species MBA4 are two transport systems that have different induction patterns and substrate specificities. It is envisaged that the shapes and the three dimensional structures of the solutes determine their recognition or exclusion by the two transport systems. PMID:23167477

2012-01-01

185

Reaction of nerve agents with phosphate buffer at pH 7.  

PubMed

Chemical weapon nerve agents, including isopropyl methylphosphonofluoridate (GB or Sarin), pinacolyl methylphosphonofluoridate (GD or Soman), and S-(2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX), are slow to react in aqueous solutions at midrange pH levels. The nerve agent reactivity increases in phosphate buffer at pH 7, relative to distilled water or acetate buffer. Reactions were studied using (31)P NMR. Phosphate causes faster reaction to the corresponding alkyl methylphosphonic acids, and produces a mixed phosphate/phosphonate compound as an intermediate reaction product. GB has the fastest reaction rate, with a bimolecular rate constant of 4.6 × 10(-3) M(-1)s(-1)[PO(4)(3-)]. The molar product branching ratio of GB acid to the pyro product (isopropyl methylphosphonate phosphate anhydride) is 1:1.4, independent of phosphate concentration, and the pyro product continues to react much slower to form GB acid. The pyro product has two doublets in the (31)P NMR spectrum. The rate of reaction for GD is slower than GB, with a rate constant of 1.26 × 10(-3) M(-1)s(-1) [PO(4)(3-)]. The rate for VX is considerably slower, with a rate constant of 1.39 × 10(-5) M(-1)s(-1) [PO(4)(3-)], about 2 orders of magnitude slower than the rate for GD. The rate constant of the reaction of GD with pyrophosphate at pH 8 is 2.04 × 10(-3) min(-1) at a concentration of 0.0145 M. The rate of reaction for diisopropyl fluorophosphate is 2.84 × 10(-3) min(-1) at a concentration of 0.153 M phosphate, a factor of 4 slower than GD and a factor of 15 slower than GB, and there is no detectable pyro product. The half-lives of secondary reaction of the GB pyro product in 0.153 and 0.046 M solution of phosphate are 23.8 and 28.0 h, respectively, which indicates little or no dependence on phosphate. PMID:22667763

Creasy, William R; Fry, Roderick A; McGarvey, David J

2012-07-12

186

Buffered Electrochemical Polishing of Niobium  

SciTech Connect

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

Gianluigi Ciovati, Hui Tian, Sean Corcoran

2011-03-01

187

Improvements in multimedia data buffering using master/slave architecture  

SciTech Connect

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

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

1996-12-31

188

Electrospun cellulose acetate-garnet nanocomposite magnetic fibers for bioseparations.  

PubMed

Cellulose acetate fibers with magnetic properties have recently attracted much attention because of their potential novel applications in biomedicine such as for cell and protein separations, magnetic resonance imaging contrast agents, and magnetic filters. In this work, as synthesized yttrium iron garnet and gadolinium substituted yttrium iron garnet nanoparticles have been used to generate magnetic filter paper. Garnet nanoparticles dispersed in cellulose acetate polymer solutions were electrospun as free-standing nonwoven fiber mats as well as on cellulose filter paper substrates resulting in magnetic filter papers. The magnetic fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and superconducting quantum interference device (SQUID) magnetic property measurements. The resulting magnetic polymer nanocomposites can be easily picked up by an external magnet from a liquid medium. Fluorescein isothiocyanate (FITC) labeled bovine serum albumin (BSA) was separated from solution by using the magnetic filter paper. PMID:24341636

Munaweera, Imalka; Aliev, Ali; Balkus, Kenneth J

2014-01-01

189

Molecular Structure of Ethyl acetate  

NSDL National Science Digital Library

Ethyl acetate is a colorless, volatile liquid with a mild and fragrant odor. It is used as solvent in chemistry laboratories but can also be found in many household products such as paints, coatings, and adhesives. The compound is also used in some extraction processes such as decaffeination or purification of antibiotics. It is present in both nail polish and removers. Some synthetic fruit essences may contain this and other esters. Etymologists like to use this solvent for insect collecting as the vapor kill the insect quickly and keep it soft for mounting.

2006-03-08

190

A Novel Traffic Independent NNC for Dynamic Buffer Tuning to Shorten the RTT of a TCP Channel  

Microsoft Academic Search

The proposed neural network controller (NNC) is for user\\/server level dynamic buffer tuning. It eliminates overflow by making the buffer length always cover the queue length adaptively on the fly. The NNC and the AQM (active queue management) mechanism(s) at the system\\/router level together form a unified buffer overflow prevention solution for the TCP channels. The NNC provides the following

Wilfred W. K. Lin; Allan K. Y. Wong; Tharam S. Dillon

2005-01-01

191

Spatial buffering of potassium ions in brain extracellular space.  

PubMed Central

It has long been assumed that one important mechanism for the dissipation of local potassium gradients in the brain extracellular space is the so-called spatial buffer, generally associated with glial cells. To date, however, there has been no analytical description of the characteristic patterns of K(+) clearance mediated by such a mechanism. This study reanalyzed a mathematical model of Gardner-Medwin (1983, J. Physiol. (Lond.). 335:393-426) that had previously been solved numerically. Under suitable approximations, the transient solutions for the potassium concentrations and the corresponding membrane potentials of glial cells in a finite, parallel domain were derived. The analytic results were substantiated by numerical simulations of a detailed two-compartment model. This simulation explored the dependence of spatial buffer current and extracellular K(+) on the distribution of inward rectifier K(+) channels in the glial endfoot and nonendfoot membranes, the glial geometric length, and the effect of passive KCl uptake. Regarding the glial cells as an equivalent leaky cable, the analyses indicated that a maximum endfoot current occurs when the glial geometric length is equal to the corresponding electrotonic space constant. Consequently, a long glial process is unsuitable for spatial buffering, unless the axial space constant can match the length of the process. Finally, this study discussed whether the spatial buffer mechanism is able to efficiently transport K(+) over distances of more than several glial space constants. PMID:10827962

Chen, K C; Nicholson, C

2000-01-01

192

Buffers Strips, Common-Sense Conservation  

NSDL National Science Digital Library

This recent publication from the Natural Resources Conservation Service (NRCS) and the National Conservation Buffer Team focuses on the practices, agricultural programs, and national programs that promote conservation buffers -- "strips or small areas of land in permanent vegetation" to help control potential pollutants and other environmental concerns. NRCS outlines specific programs and educational initiatives for many different types of "filter strips, field borders, grassed waterways, field windbreaks, shelterbelts, contour grass strips, and riparian (streamside) buffers."

193

Complexation of chitosan with acetic acid according to Fourier transform Raman spectroscopy data  

NASA Astrophysics Data System (ADS)

The results of the interaction between the protonated chitosan (CHI) macromolecule and the acetate ion in dilute acetic acid solutions were studied by Fourier transform Raman spectroscopy and quantum-chemical modeling. The complexation of CHI with the acetate ion showed itself as the 934 cm-1 band in the Raman spectrum, which suggests the formation of [CHI+ · CH3COO-] type ion pairs. It was concluded that a comparative analysis of the integrated intensities of the Raman bands in the range 880-940 cm-1 makes it possible to judge about the relative content of hydrated acetate ions, CHI macromolecules of the [CHI+ · CH3COO-] complex, and acetic acid molecules not involved in CHI protonation.

Mikhailov, G. P.; Tuchkov, S. V.; Lazarev, V. V.; Kulish, E. I.

2014-06-01

194

Melatonin: Buffering the Immune System  

PubMed Central

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

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

2013-01-01

195

All-optical buffering for DPSK packets  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

196

SODR Memory Control Buffer Control ASIC  

NASA Technical Reports Server (NTRS)

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.

Hodson, Robert F.

1994-01-01

197

Biodegradable cellulose acetate nanofiber fabrication via electrospinning.  

PubMed

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

Christoforou, Theopisti; Doumanidis, Charalabos

2010-09-01

198

BuffersA guide for the preparation and use of buffers in biological systems  

E-print Network

, an affiliate of Merck KGaA, Darmstadt, Germany. All rights reserved. Buffers #12;ii A word to our valued, Marketing #12;iii Table of Contents: Why does Calbiochem® Biochemicals Publish a Booklet on Buffers

Lebendiker, Mario

199

Investigation of solid-phase buffers for sulfur-oxidizing autotrophic denitrification.  

PubMed

This paper investigates biological denitrification using autotrophic microorganisms that use elemental sulfur as an electron donor. In this process, for each gram of nitrate-nitrogen removed, approximately 4.5 g of alkalinity (as calcium carbonate) are consumed. Because denitrification is severely inhibited below pH 5.5, and alkalinity present in the influent wastewaters is less than the alkalinity consumed, an external buffer was needed to arrest any drop in pH from alkalinity consumption. A packed-bed bioreactor configuration is ideally suited to handle variations in flow and nitrate loading from decentralized wastewater treatment systems, as it is a passive system and thus requires minimal maintenance; therefore, a solid-phase buffer packed with the elemental sulfur in the bioreactor is most suitable. In this research, marble chips, limestone, and crushed oyster shells were tested as solid-phase buffers. Bench- and field-scale studies indicated that crushed oyster shell was the most suitable buffer based on (1) the rate of dissolution of buffer and the buffering agent released (carbonate, bicarbonate, or hydroxide), (2) the ability of the buffer surface to act as host for microbial attachment, (3) turbidity of the solution upon release of the buffering agent, and (4) economics. PMID:18198697

Sengupta, Sukalyan; Ergas, Sarina J; Lopez-Luna, Erika

2007-12-01

200

Super Saturated Solution Lab Demo  

NSDL National Science Digital Library

This video from the Midwest Regional Center for Nanotechnology Education (NANO-LINK) demonstrates the growth of sodium acetate crystals. The brief video runs only 2:32 long and shows what happens when a small crystal of sodium acetate is added to a solution of super saturated sodium acetate. Each step of the experiment is clearly explained in the video so that it can easily be recreated.

201

Resilience to suicidality: The buffering hypothesis  

Microsoft Academic Search

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

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

2011-01-01

202

Color image quantization for frame buffer display  

Microsoft Academic Search

Algorithms for adaptive, tapered quantization of color images are described. The research is motivated by the desire to display high-quality reproductions of color images with small frame buffers. It is demonstrated that many color images which would normally require a frame buffer having 15 bits per pixel can be quantized to 8 or fewer bits per pixel with little subjective

Paul Heckbert

1982-01-01

203

METAMORPHIC VIRUSES WITH BUILT BUFFER OVERFLOW  

E-print Network

METAMORPHIC VIRUSES WITH BUILT BUFFER OVERFLOW The Faculty of the Department of Computer Science of the Requirements for the Degree METAMORPHIC VIRUSES WITH BUILT BUFFER OVERFLOW A Research Project Presented of the Requirements for the Degree Master of Computer Science by Ronak Shah Spring 2010 METAMORPHIC VIRUSES WITH BUILT

Stamp, Mark

204

Understanding the Science Behind Riparian Forest Buffers  

E-print Network

a Understanding the Science Behind Riparian Forest Buffers: Effects on Water Quality #12;b *Faculty Cheatham Hall, Blacksburg, VA 24061 Understanding the Science Behind Riparian Forest Buffers: Effects on Water Quality by Julia C. Klapproth and James E. Johnson* The riparian area is that area of land located

Liskiewicz, Maciej

205

Understanding the Science Behind Riparian Forest Buffers  

E-print Network

Understanding the Science Behind Riparian Forest Buffers: Planning, Establishment, and Maintenance Riparian Forest Buffers: Planning, Establishment, and Maintenance by Julia C. Klapproth and James E. Johnson* The riparian area is that area of land located immediately adjacent to streams, lakes, or other

Liskiewicz, Maciej

206

Understanding the Science Behind Riparian Forest Buffers  

E-print Network

a Understanding the Science Behind Riparian Forest Buffers: Effects on Plant and Animal Communities, Virginia Tech, 324 Cheatham Hall, Blacksburg, VA 24061 Understanding the Science Behind Riparian Forest Buffers: Effects on Plant and Animal Communities by Julia C. Klapproth and James E. Johnson* The riparian

Liskiewicz, Maciej

207

Understanding the Science Behind Riparian Forest Buffers  

E-print Network

Understanding the Science Behind Riparian Forest Buffers: Factors Influencing Adoption #12;*Faculty Cheatham Hall, Blacksburg, VA 24061 Understanding the Science Behind Riparian Forest Buffers: Factors Influencing Adoption by Julia C. Klapproth and James E. Johnson* The riparian area is that area of land

Liskiewicz, Maciej

208

The buffer capacity of airway epithelial secretions  

PubMed Central

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

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

2014-01-01

209

The buffer capacity of airway epithelial secretions.  

PubMed

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

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

2014-01-01

210

Multicommodity Flow Algorithms for Buffered Global Routing  

E-print Network

Multicommodity Flow Algorithms for Buffered Global Routing Christoph Albrecht, Andrew B. Kahng, Ion on a multicommodity flow formulation for the buffered global routing problem. Multicommodity flow based global routing to be a distinct advantage of multicommodity flow based methods over all other approaches to global routing

Zelikovsky, Alexander

211

The feeding value of water and acetic acid reconstituted sorghum grain for lactating dairy cows  

E-print Network

. Lane Sorghum grain, reconstituted to 30? moisture using water or an acetic acid solution to result in 2l acetic acid in the reconsti- tuted grain, was ensiled and compared to air-dry grain in digestion, production, and volatile fatty acid studies... production were not affected by the rations. An 1n vivo volatile fatty acid study was conducted w1th a f1stulated steer fed rat1ons containing dry grain, water reconsti- tuted gra1n, and grain reconstituted with 0. 5, 1. 0, 1. 5, 2. 0 and 2. 5K acetic...

Bade, David Heinie

1972-01-01

212

Positron scattering from vinyl acetate  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

213

[Mechanical buffering characteristics of feline paw pads].  

PubMed

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

Zhang, Xiaopeng; Yang, Jialing; Yu, Hui

2012-12-01

214

Extractive fermentation of acetic acid  

SciTech Connect

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.

Busche, R.M. [Bio En-Gene-Er Associates, Inc., Wilmington, DE (United States)

1991-12-31

215

Alkaline buffers release EDRF from bovine cultured aortic endothelial cells.  

PubMed Central

1. Release of endothelium-derived relaxing factor (EDRF) and prostacyclin (PGI2) from bovine cultured aortic endothelial cells (EC) was measured by bioassay and radioimmunoassay, respectively. 2. Bradykinin (BK, 3-30 pmol), adenosine diphosphate (ADP, 2-6 nmol) or the sodium ionophore monensin (40-100 nmol) injected through a column of EC released EDRF. L-Arginine free base (FB; 10-20 mumol) or D-arginine FB (10-20 mumol) injected through the column of EC released similar amounts of EDRF and also caused an increase in pH of the Krebs solution perfusing the EC from 7.5-8.0 to 8.6-9.5. Sodium carbonate (Na2CO3) an alkaline buffer which caused the same changes in the pH of the Krebs solution also induced the same release of EDRF. The hydrochloride salts of L- or D-arginine did not cause either release of EDRF when injected through the column of EC or increases in the pH of the Krebs solution. 3. Inhibitors of either diacylglycerol lipase (RHC 80267) or kinase (R59022) inhibited the release of EDRF induced by BK or ADP but potentiated the release induced by L-arginine FB, monensin (40-100 nmol) or alkaline buffer (Na2CO3). R59022 and RHC 80267 infused through the EC increased the basal release of EDRF. 4. When calcium chloride was omitted from the Krebs solution the release of EDRF induced by alkaline buffer (Na2CO3; pH 8.6-9.5) or L-arginine FB (10-20 mumol) was selectively inhibited when compared to that induced by BK (3-30 pmol) or ADP (2-6 nmol). This inhibition was reversed when calcium (2.5 mM) was restored. 5. NG-monomethyl-L-arginine (NMMA; 30 microM) inhibited release of EDRF induced by BK (10-30 pmol) or alkaline buffers (Na2CO3 or D-arginine FB; pH 8.6-9.5). This inhibition was partially reversed by L- but not D-arginine FB or HCl (30-100 microM). 6. Prostacyclin was released when BK (10 pmol), ADP (2 nmol) or arachidonic acid (30 nmol) were injected through the column of EC. However, monensin (40 nmol) or alkaline buffers (pH 8.6-9.5) did not release detectable amounts of PGI2 as measured by radioimmunoassay for 6-oxo-prostaglandin F1 alpha.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1884092

Mitchell, J. A.; de Nucci, G.; Warner, T. D.; Vane, J. R.

1991-01-01

216

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

PubMed Central

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

Takahashi, Ohgi; Kirikoshi, Ryota; Manabe, Noriyoshi

2015-01-01

217

Acetic Acid can catalyze succinimide formation from aspartic Acid residues by a concerted bond reorganization mechanism: a computational study.  

PubMed

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

Takahashi, Ohgi; Kirikoshi, Ryota; Manabe, Noriyoshi

2014-01-01

218

Thermal decarboxylation of acetic acid: Implications for origin of natural gas  

USGS Publications Warehouse

Laboratory experiments on the thermal decarboxylation of solutions of acetic acid at 200??C and 300??C were carried out in hydrothermal equipment allowing for on-line sampling of both the gas and liquid phases for chemical and stable-carbon-isotope analyses. The solutions had ambient pH values between 2.5 and 7.1; pH values and the concentrations of the various acetate species at the conditions of the experiments were computed using a chemical model. Results show that the concentrations of acetic acid, and not total acetate in solution, control the reaction rates which follow a first order equation based on decreasing concentrations of acetic acid with time. The decarboxylation rates at 200??C (1.81 ?? 10-8 per second) and 300??C (8.17 ?? 10-8 per second) and the extrapolated rates at lower temperatures are relatively high. The activation energy of decarboxylation is only 8.1 kcal/mole. These high decarboxylation rates, together with the distribution of short-chained aliphatic acid anions in formation waters, support the hypothesis that acid anions are precursors for an important portion of natural gas. Results of the ??13C values of CO2, CH4, and total acetate show a reasonably constant fractionation factor of about 20 permil between CO2 and CH4 at 300??C. The ??13C values of CO2 and CH4 are initially low and become higher as decarboxylation increases. ?? 1983.

Kharaka, Y.K.; Carothers, W.W.; Rosenbauer, R.J.

1983-01-01

219

Filtrates & Residues: A "Semimicro" Spectrophotometric Determination of the Ksp of Silver Acetate at Various Temperatures.  

ERIC Educational Resources Information Center

Examines a solubility laboratory experiment using silver acetate and spectrophotometers for an Advanced Placement chemistry course. Covers experimental procedure, analysis of saturated solutions, and a discussion of chemistry involved. Includes an absorbance curve for silver ions and solution preparation suggestions. (ML)

Liebermann, John, Jr.; Yun, Ki J.

1988-01-01

220

Chelation and permeation of heavy metals using affinity membranes from cellulose acetate–chitosan blends  

Microsoft Academic Search

Affinity membranes have attracted the attention of membrane researchers especially in the field of wastewater treatment specifically in removing heavy metals by chelation from aqueous solutions. In the present work, several membranes are made from either cellulose di-acetate (CA) or CA together with chitosan (CS) solutions, the CS prepared in our lab from shrimp shells or from readymade shrimp or

M. M. Naim; H. E. M. Abdel Razek

2012-01-01

221

21 CFR 184.1005 - Acetic acid.  

Code of Federal Regulations, 2011 CFR

...as GRAS § 184.1005 Acetic acid. (a) Acetic acid (C2 H4 O2 , CAS Reg. No. 64-19-7) is known as ethanoic acid. It occurs naturally in plant...fermentation of carbohydrates or by organic synthesis. The principal...

2011-04-01

222

A freshwater anaerobe coupling acetate oxidation to tetrachloroethylene dehalogenation.  

PubMed Central

Strain TT4B has been isolated from anaerobic sediments known to be contaminated with a variety of organic solvents. It is a gram-negative, rod-shaped bacterium and grew anaerobically with acetate as the electron donor and tetrachloroethylene as the electron acceptor in a mineral medium. cis-Dichloroethylene was the halogenated product. This strain did not grow fermentatively and used only acetate or pyruvate as electron donors. Tetrachloroethylene and trichloroethylene were used as electron acceptors, as were ferric nitriloacetate and fumarate. Nitrogen and sulfur oxyanions were not able to substitute as the electron acceptor for this organism. Modest growth occurred in a two-phase system with 1 ml of hexadecane containing 50 to 200 mM tetrachloroethylene (aqueous concentrations, 25 to 100 microM) and 10 ml of anaerobic mineral solution with Na2S as the reducing agent. Growth was completely inhibited at tetrachloroethylene levels above 100 microM. PMID:8900001

Krumholz, L R; Sharp, R; Fishbain, S S

1996-01-01

223

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 ...

224

Electrophoretic mobilities of erythrocytes in various buffers  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

225

A novel structure of optical buffer  

NASA Astrophysics Data System (ADS)

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

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

2005-02-01

226

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

Microsoft Academic Search

Etchant solutions comprising a redox buffer can be used during the release etch step to reduce damage to the structural layers of a MEMS device that has noble material films. A preferred redox buffer comprises a soluble thiophosphoric acid, ester, or salt that maintains the electrochemical potential of the etchant solution at a level that prevents oxidation of the structural

Matthew G

2009-01-01

227

Contribution of dialysate acetate to energy metabolism: Metabolic implications  

Microsoft Academic Search

Contribution of dialysate acetate to energy metabolism: Metabolic implications. During hemodialysis large amounts of acetate enter the bloodstream. Generally, it is assumed that this exogenous acetate load is oxidized immediately to carbon dioxide and water; however, the rate of plasma acetate oxidation and the effect of acetate oxidation on energy metabolism during hemodialysis has not been determined previously. The rates

Charles L Skutches; Miles H Sigler; Brendan P Teehan; Joseph H Cooper; George A Reichard

1983-01-01

228

Effect of composite microstructure on electrical and mechanical properties of poly(vinyl acetate) composites with carbon black and clay.  

E-print Network

The electrical and mechanical behavior of carbon black filled poly(vinyl acetate) latex-based and solution-based polymer composites was examined. A set of experiments were performed to distinguish composites with a segregated network (emulsion...

Miriyala, Sethu M.

2009-05-15

229

Desvenlafaxinium chloranilate ethyl acetate solvate  

PubMed Central

In the cation of the title compound, C16H26NO2 +·C6HCl2O4 ?·C4H8O2, the 1-hy­droxy-cyclo­hexyl ring adopts a slightly distorted chair conformation. The dihedral angle between the mean planes of the 1-hy­droxy­cyclo­hexyl and 4-hy­droxy­phenyl rings is 84.0?(8)°. In the anion, the hydroxyl H atom is twisted slightly out of the ring plane with a C—C—O—H torsion angle of ?171.9°. Disorder was modeled for the methyl group of the acetate group in the solvate with an occupancy ratio of 0.583?(15): 0.417?(15). In the crystal, O—H?O hydrogen bonds are observed between cations and between cations and anions, while bifuricated N—H?(O,O) cation–anion hydrogen bonds are also present, forming chains along [010] and [100]. In addition weak cation–anion and cation–solvate C—H?O inter­actions occur. PMID:24098238

Kaur, Manpreet; Jasinski, Jerry P.; Butcher, Ray J.; Yathirajan, H. S.; Byrappa, K.

2013-01-01

230

Thermal decarboxylation of acetate. Part II. Boundary conditions for the role of acetate in the primary migration of natural gas and the transportation of metals in hydrothermal systems  

NASA Astrophysics Data System (ADS)

Acetate can mediate the primary migration of natural gas from tight, water-laden source rocks by acting as a mobile precursor that is expelled during compaction to resevoir rocks where subsequent decarboxylation yields methane. The viability of this mechanism is demonstrated by integrating, via a computer model, the experimental kinetic rate data for acetate decarboxylation that are presented in Part I with the thermal-temporal-spatial relationships of sediment and fluid in the upper portions of actively forming sedimentary basins. Specifically, this analysis indicates that when the enthalpy of activation is between 32 and 42 kcal · mol -1, and the temperature is between 80 and 130°C, acetate can survive the thermal regime of a typical sedimentary basin long enough to migrate out of the source rocks and yet decarboxylate to form a natural gas deposit within the time frame imposed by the age of the basin sediments. The results suggest that this migration mechanism for natural gas may be predominant within a significant geological and chemical window. A similar analysis has shown that acetate can survive moderate hydrothermal temperatures (<300°C) long enough to promote the mobility of metals as acetate complexes. Ongoing experimental studies now show that metal-acetate complexes are stronger than the analogous chloro-complexes and may account for a large proportion of the metal in hydrothermal solutions with access to organic material.

Drummond, S. E.; Palmer, Donald A.

1986-05-01

231

Competitive Parallel Disk Prefetching and Buffer Management  

E-print Network

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

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

2000-01-01

232

Buffered lidocaine for skin infiltration prior to hemodialysis.  

PubMed

This study compared the effects of buffered versus unbuffered lidocaine when used as local anesthetic in preparation for cannulation of the arterial and venous sites of children requiring hemodialysis. The subjects for this study were seven children, ages 6-18 years, observed during 101 dialysis treatments. For each subject undergoing hemodialysis on a given day, one syringe containing 1% lidocaine (L) and one containing buffered lidocaine (BL) were prepared. The BL solution was prepared by adding 2 mL of 8.4% sodium bicarbonate to 20 mL of 1% lidocaine just prior to use. The choice of local anesthetic used for cannulation of the arterial or venous site was randomly assigned to be either L or BL. Nurses, raters, and subjects were blind to contents of the syringe. The procedures for piercing the skin, pausing, and infiltrating were standardized, as was the volume administered. Speed of injection was not controlled. Comparisons of self-reported pain and behavioral observations for L versus BL revealed no significant differences for pain of infiltration or pain of cannulation. Technique variables such as the speed of injection, which tended to be very slow for these children, appear to significantly influence infiltration pain and the relative merits of buffering. PMID:7629414

Richtsmeier, A J; Hatcher, J W

1995-04-01

233

21 CFR 522.2478 - Trenbolone acetate and estradiol benzoate.  

Code of Federal Regulations, 2010 CFR

...false Trenbolone acetate and estradiol benzoate. 522.2478 Section 522.2478...2478 Trenbolone acetate and estradiol benzoate. (a) Specifications . Each implant...trenbolone acetate and 3.5 mg estradiol benzoate. (2) 4 pellets, each pellet...

2010-04-01

234

New approach for the production of cellulose acetate: acetylation of mechanical pulp with subsequent isolation of cellulose acetate by differential solubility  

SciTech Connect

A heretofore uninvestigated approach to the production of cellulose acetate is the acetylation of mechanical pulp with subsequent isolation of the cellulose derivative by differential solubility. The mechanical pulp is produced by refining aspen wood chips in a disc-refiner. Two conventional acetylation techniques, the fibrous and solution process, are employed to acetylate all components of the pulp. The cellulose acetate is isolated from the acetylated lignin and hemicellulose by dissolving in dichloromethane/methanol (9:1, v/v). The advantage of this new approach is that the high costs involved in using an extensively purified dissolving pulp are avoided. Both procedures yield a product that is about 84% cellulose acetate. The remaining acetylated components are lignin and hemicellulose. The average lignin content of the product from the solution process is 3.5% (1.5-4.7% range), and for the fibrous process it is 3.4% (1.2-5% range). The hemicellulose component averages 5.8% (2.5-9.1% range) for the solution process and 6.5% (3.0-8.7% range) for the fibrous process. The yield of cellulose acetate, based on the cellulose content of the original pulp and the product, is 75% for the solution process and 75-80% for the fibrous process. The cellulose acetate degree of polymerization (DP) is dependent on the sulfuric acid catalyst concentration, and on the reaction time in the case of the solution process. The product can be produced with a weight average DP from 1853 to 65 for the solution process, and 980 to 284 for the fibrous process. Applications for the product include lacquers, plastic films, and packaging.

Barkalow, D.G.

1987-01-01

235

/GaAs (001) Metamorphic Buffer Layers  

NASA Astrophysics Data System (ADS)

The design of metamorphic buffer layers for semiconductor devices with reduced defect densities requires control of lattice relaxation and dislocation dynamics. Graded layers are beneficial for the design of these buffers because they reduce the threading dislocation density by (1) allowing the distribution of the misfit dislocations throughout the buffer layer therefore reducing pinning interactions, and (2) enhancing mobility from the high built-in surface strain which helps to sweep out threading arms. In this work, we considered heterostructures involving a linearly-graded (type A) or step-graded (type B) buffer grown on a GaAs (001) substrate. For each structure type, we studied the equilibrium configuration and the kinetically-limited lattice relaxation and non-equilibrium threading dislocations by utilizing a dislocation dynamics model. In this work, we have also considered heterostructures involving a constant composition ZnS y Se1- y device layer grown on top of a GaAs (001) substrate with an intermediate buffer layer of linearly-graded (type C) or step-graded (type D) ZnS y Se1- y . For each structure type, we studied the requirements on the thickness and compositional profile in the buffer layer for the elimination of all mobile threading dislocations from the device layer by the dislocation compensation mechanism.

Kujofsa, T.; Ayers, J. E.

2014-08-01

236

Controlled Chemical Doping of Semiconductor Nanocrystals Using Redox Buffers  

SciTech Connect

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

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

2013-07-09

237

Anaerobic model for high-solids or high-temperature digestion - additional pathway of acetate oxidation.  

PubMed

Current anaerobic digestion models cannot properly simulate processes that are operated under high solids concentrations or high temperatures. A modification to existing models has been implemented by adding important missing degradation pathways, to accommodate these systems without artificially recalibrating the model parameters. Specifically, we implemented the alternate acetate oxidizing mechanism that is more tolerant to ammonia than the standard aceticlastic pathway. Inhibition values were estimated and an empirical function has been used to apply ammonia inhibition. The model also relates metabolic activity to un-ionised species such as undissociated acetic acid as substrate (although not obligatory for all organisms) and unionised ammonia as inhibitor. The model relies on an equilibrium chemistry module (e.g. including the phosphate buffer), resulting in more accurate pH predictions, which is crucial for proper modeling of CO2 and NH3 stripping. Calibration results from three case-studies modeling thermal hydrolysis and subsequent digestion of sludge are presented. PMID:24759522

Wett, B; Takács, I; Batstone, D; Wilson, C; Murthy, S

2014-01-01

238

Disruption of the acetate kinase (ack) gene of Clostridium acetobutylicum results in delayed acetate production.  

PubMed

In microorganisms, the enzyme acetate kinase (AK) catalyses the formation of ATP from ADP by de-phosphorylation of acetyl phosphate into acetic acid. A mutant strain of Clostridium acetobutylicum lacking acetate kinase activity is expected to have reduced acetate and acetone production compared to the wild type. In this work, a C. acetobutylicum mutant strain with a selectively disrupted ack gene, encoding AK, was constructed and genetically and physiologically characterized. The ack (-) strain showed a reduction in acetate kinase activity of more than 97% compared to the wild type. The fermentation profiles of the ack (-) and wild-type strain were compared using two different fermentation media, CGM and CM1. The latter contains acetate and has a higher iron and magnesium content than CGM. In general, fermentations by the mutant strain showed a clear shift in the timing of peak acetate production relative to butyrate and had increased acid uptake after the onset of solvent formation. Specifically, in acetate containing CM1 medium, acetate production was reduced by more than 80% compared to the wild type under the same conditions, but both strains produced similar final amounts of solvents. Fermentations in CGM showed similar peak acetate and butyrate levels, but increased acetoin (60%), ethanol (63%) and butanol (16%) production and reduced lactate (-50%) formation by the mutant compared to the wild type. These findings are in agreement with the proposed regulatory function of butyryl phosphate as opposed to acetyl phosphate in the metabolic switch of solventogenic clostridia. PMID:22249720

Kuit, Wouter; Minton, Nigel P; López-Contreras, Ana M; Eggink, Gerrit

2012-05-01

239

Anion buffering in the internal electrolyte resulting in extended durability of phosphate-selective electrodes.  

PubMed

The decomposition of the ionophore uranyl salophene in a polymeric membrane is the main source of the deterioration of phosphate-selective electrodes in time. Due to the efficient buffering of both phosphate and uranyl ions in the internal electrolyte solution, a significant decrease of the rate of decomposition of uranyl salophene in the membrane was observed, improving the lifetime of phosphate-selective electrodes. The most efficient buffering of such ions, resulting in the best sensor durability, was obtained using the internal electrolyte solution containing barium-uranyl phosphate mineral, meta-uranocircite II. PMID:12964780

Wojciechowski, Kamil; Wróblewski, Wojciech; Brzózka, Zbigniew

2003-07-01

240

A molecular molybdenum electrocatalyst for generating hydrogen from acetic acid or water  

NASA Astrophysics Data System (ADS)

The reaction of 2-pyridylamino-N,N-bis(2-methylene-4,6-difluorophenol) (H2L?) and MoCl5 affords a molybdenum(VI) complex [MoL?(O)2] 1, a new molecular electrocatalyst, which has been determined by X-ray crystallography. Electrochemical studies show that a molybdenum(IV) intermediate is responsible for the reductive proton to generate H2, and 1 can catalyze hydrogen evolution from acetic acid or aqueous buffer. Turnover frequency (TOF) reaches a maximum of 50.6 (in DMF) and 756 (in buffer, pH 6.0) moles of hydrogen per mole of catalyst per hour, respectively. Sustained proton reduction catalysis occurs at glassy carbon (GC) electrode to give H2 over a 72 h electrolysis period and no observable decomposition of the catalyst.

Cao, Jie-Ping; Zhou, Ling-Ling; Fu, Ling-Zhi; Zhan, Shuzhong

2014-12-01

241

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

242

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

DOEpatents

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

Hankins, Matthew G. (Albuquerque, NM)

2009-10-06

243

Acetate Causes Alcohol Hangover Headache in Rats  

PubMed Central

Background The mechanism of veisalgia cephalgia or hangover headache is unknown. Despite a lack of mechanistic studies, there are a number of theories positing congeners, dehydration, or the ethanol metabolite acetaldehyde as causes of hangover headache. Methods We used a chronic headache model to examine how pure ethanol produces increased sensitivity for nociceptive behaviors in normally hydrated rats. Results Ethanol initially decreased sensitivity to mechanical stimuli on the face (analgesia), followed 4 to 6 hours later by inflammatory pain. Inhibiting alcohol dehydrogenase extended the analgesia whereas inhibiting aldehyde dehydrogenase decreased analgesia. Neither treatment had nociceptive effects. Direct administration of acetate increased nociceptive behaviors suggesting that acetate, not acetaldehyde, accumulation results in hangover-like hypersensitivity in our model. Since adenosine accumulation is a result of acetate formation, we administered an adenosine antagonist that blocked hypersensitivity. Discussion Our study shows that acetate contributes to hangover headache. These findings provide insight into the mechanism of hangover headache and the mechanism of headache induction. PMID:21209842

Maxwell, Christina R.; Spangenberg, Rebecca Jay; Hoek, Jan B.; Silberstein, Stephen D.; Oshinsky, Michael L.

2010-01-01

244

Study of Thermodynamical Properties of Polyvinyl Acetate in Tetrahydrofuran  

NASA Astrophysics Data System (ADS)

The propagation of ultrasonic waves and the measurement of their velocity in solutions form an important tool for the evaluation of various acoustical and thermodynamical parameters which give an insight into the nature of miscibility and molecular interactions in polymer solutions. In the present study, the ultrasonic velocity, density, viscosity measurements have been made in 0.1 M solution using pulse echo overlap technique at 293 K at the different concentrations of polyvinyl acetate in tetrahydrofuran. Thermo-acoustical parameters viz., adiabatic compressibility, molar sound velocity, molar compressibility, expansion coefficient, acoustic impedance, van der Waals' constant and internal pressure have been computed from the experimental data. The nature of polymer/solvent interaction and the effect of concentration on the molecular interaction are studied. The nonlinear variations of polyvinyl acetate in tetrahydrofuran have been studied. The variation of ultrasonic velocity and other thermo-acoustical parameters shows nonlinear increase or decrease with molar concentration which suggest semi-compatibility of the polymer in the given solvent.

Tabhane, Priyanka V.; Chimankar, Omprakash P.; Tabhane, Vilas A.

2012-10-01

245

Dioxouranium (VI) complexes with cellulose acetate  

Microsoft Academic Search

Dioxouranium [UO2(VI)] complexes with three degrees of substitution of cellulose acetate, prepared from viscose pulp (DS = 2.2, 2.45 and 2.86), have been synthesis and characterized. Degree of substitution (DS) is defined as the average number of CH groups substituted on each anhydrocellulose repeat unit. Probable structures of the cellulose acetate complexes were inferred from the elemental analysis data, conductance

Altaf H. Basta; Wafaa M. Hosny

1998-01-01

246

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

PubMed Central

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

Ehsani, Ali; Jasour, Mohammad Sedigh

2012-01-01

247

Allocation of buffers to serial production lines with bottlenecks  

Microsoft Academic Search

The optimal placement of a predetermined amount of buffer capacity in balanced serial production lines is a well-understood problem: in lines with moderate variability, the optimal allocation involves equal numbers of buffers at each site; in lines with severe variability, the equal allocation is modified slightly to place more buffers toward the center of the line. Buffering unbalanced lines is

STEPHEN G. POWELL; DAVID F. PYKE

1996-01-01

248

Pain of Local Anesthetics: Rate of Administration and Buffering  

Microsoft Academic Search

Study objective: To determine the impact of administration rate and buffering on the pain associated with subcutaneous infiltration of lidocaine. Methods: Forty-two adult volunteers employed at a tertiary care center participated in this prospective, single-blinded study. Each subject received four lidocaine injections prepared and administered as follows: slow, buffered (SB); slow, unbuffered (SU); rapid, buffered (RB); rapid, unbuffered (RU). Buffering

Richard J Scarfone; Melinda Jasani; Edward J Gracely

1998-01-01

249

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

ERIC Educational Resources Information Center

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…

Orgill, MaryKay; Sutherland, Aynsley

2008-01-01

250

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

PubMed

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

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

2013-11-20

251

Preparation of Buffers. An Experiment for Quantitative Analysis Laboratory  

NASA Astrophysics Data System (ADS)

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.

Buckley, P. T.

2001-10-01

252

Distinguishing between Luminal and Localized Proton Buffering Pools in Thylakoid Membranes1  

PubMed Central

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

Ewy, Robert G.; Dilley, Richard A.

2000-01-01

253

Measuring acetic acid dimer modes by ultrafast time-domain Raman spectroscopy.  

PubMed

Acetic acid is capable of forming strong multiple hydrogen bonds and therefore different dimeric H-bonded structures in neat liquid phase and in solutions. The low frequency Raman spectra of acetic acid (neat, in aqueous solution and as a function of temperature) were obtained by ultrafast time and polarization resolved optical Kerr effect (OKE) measurements. Isotropic OKE measurements clearly reveal a specific totally symmetric mode related to the dimeric structure H-bond stretching mode. The effects of isotope substitution, water dilution and temperature on this mode were investigated. These results together with anisotropic OKE measurements and density functional theory calculations for a number of possible dimers provide strong evidence for the cyclic dimer structure being the main structure in liquid phase persisting down to acetic acid concentrations of 10 M. Some information about the dimer structure and concentration dependence was inferred. PMID:21625711

Heisler, Ismael A; Mazur, Kamila; Yamaguchi, Sayuri; Tominaga, Keisuke; Meech, Stephen R

2011-09-14

254

Comparative analyses of universal extraction buffers for assay of stress related biochemical and physiological parameters.  

PubMed

Comparative efficiency of three extraction solutions, including the universal sodium phosphate buffer (USPB), the Tris-HCl buffer (UTHB), and the specific buffers, were compared for assays of soluble protein, free proline, superoxide radical ([Formula: see text]), hydrogen peroxide (H2O2), and the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), and glutathione reductase (GR) in Populus deltoide. Significant differences for protein extraction were detected via sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis (2-DE). Between the two universal extraction buffers, the USPB showed higher efficiency for extraction of soluble protein, CAT, GR, [Formula: see text], GPX, SOD, and free proline, while the UTHB had higher efficiency for extraction of APX, POD, and H2O2. When compared with the specific buffers, the USPB showed higher extraction efficiency for measurement of soluble protein, CAT, GR, and [Formula: see text], parallel extraction efficiency for GPX, SOD, free proline, and H2O2, and lower extraction efficiency for APX and POD, whereas the UTHB had higher extraction efficiency for measurement of POD and H2O2. Further comparisons proved that 100 mM USPB buffer showed the highest extraction efficiencies. These results indicated that USPB would be suitable and efficient for extraction of soluble protein, CAT, GR, GPX, SOD, H2O2, [Formula: see text], and free proline. PMID:25036412

Han, Chunyu; Chan, Zhulong; Yang, Fan

2015-10-01

255

Acetate Transport and Utilization in the Rat Brain  

PubMed Central

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

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

2009-01-01

256

Autolysis of cell walls from polygalacturonase-antisense tomato fruit in simulated apoplastic solutions.  

PubMed

Autolysis of cell walls from polygalacturonase (PG)-antisense tomato fruit was studied in a conventional buffer designed to maximize the catalytic activity of PG (30 mM sodium acetate, 150 mM NaCl, pH 4.5), and in solutions mimicking the pH and mineral composition of the fruit apoplast at the mature-green and ripe stages. Autolytic release of uronic acids was very limited under simulated apoplastic conditions compared with the conventional buffer, but minimal differences in the release of reducing groups were observed among the incubation conditions. Autolytic release of uronic acids from active walls was lower than solubilization from enzymically inactive walls. Uronic acids that remained ionically bound to the cell walls during autolysis were subsequently extracted and analyzed by size exclusion chromatography. The elution profiles of ionically bound uronic acids from cell walls incubated under optimal conditions were similar for all ripening stages. In solutions mimicking the pH and mineral composition of the apoplast of mature-green and ripe fruit, uronic acids extracted from pink and ripe fruit cell walls showed a decrease in average molecular mass compared with polymers from mature-green cell walls. The results suggest that the composition of the incubation solution exert strong influence on PG-independent cell wall autolysis and that enzymically active walls restrain PG-independent pectin solubilization. PMID:21420309

Almeida, Domingos P F; Huber, Donald J

2011-06-01

257

Riparian forests buffer panel final report  

SciTech Connect

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.

NONE

1996-10-01

258

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

PubMed

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. PMID:25416587

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

2014-11-22

259

Pharmacological activity of hyperforin acetate in rats.  

PubMed

Hyperforin, the main antidepressant component of Hypericum extract, is not stable with regard to heat and light. Therefore, we investigated a newly synthetized derivative, hyperforin acetate. Herein we demonstrate its efficacy in animal models sensitive to antidepressant and anxiolytic drugs. In the forced swimming test, triple administration of hyperforin (5-20 mg/kg) significantly reduced the immobility time of rats, while in the learned helplessness test a daily treatment of 10 mg/kg for seven consecutive days was necessary to elicit an antidepressant effect. In the elevated plus-maze and in the light-dark test, the acute administration of hyperforin acetate (3-5 mg/kg) exerted an anxiolytic activity, which, however, was smaller than that of diazepam. The effect was inhibited by the pretreatment of rats with metergoline, a serotoninergic antagonist, but not with CGS-8216, a benzodiazepine receptor antagonist. Hyperforin acetate (3-10 mg/kg) was also able to reduce locomotion in rats without eliciting myorelaxant activity. As Hypericum extract was claimed to exert a potential influence on the liver drug metabolizing system, we showed that neither acute nor repeated oral doses of hyperforin acetate altered pentobarbital sleeping time in rats. Taken together, the present results show that hyperforin acetate is a pharmacologically active derivative of hyperforin and may be a starting point from which to develop new compounds for therapeutic purposes. PMID:12478215

Zanoli, P; Rivasi, M; Baraldi, C; Baraldi, M

2002-12-01

260

Effect of Delay and Buffering on Jitter-Free Streaming over Random VBR Channels  

E-print Network

services, such as TV news, music video, and online movies. Streaming multimedia are likely to become major1 Effect of Delay and Buffering on Jitter-Free Streaming over Random VBR Channels Guanfeng Liang, or jitter-free probability. Previous literature has described solutions to estimate the jitter-free

Liang, Ben

261

Spectrophotometric Determination of Lorsartan Potassium and its Dosage Form by Bromothymol Blue and Phosphate Buffer  

Microsoft Academic Search

Simple, rapid and accurate, spectrophotometric method for the determination of losartan potassium by using bromothymol blue as a chromogen and phosphate buffer solution (pH 3-4) as a diluting agent was developed. The developed colour shows maximum absorbance at 620 nm and it was observed that the absorbance of different dilution from the plots the calibration curve between the concentrations in

P. PARTHIBAN; V. ALAGARSAMY; M. SUNIL; J. VAIDHYA MAHUL; T. RAMA MOHAN

262

The design and implementation of the buffer manager for an experimental relational database management system  

E-print Network

buffer management and conventional operating system buffer management are discussed. The main requirements and functions of the buffer manager are described; the buffer set model, the data structures, and the algorithms used to support buffer management...

Li, Zaichun

1994-01-01

263

Microcoil NMR study of the interactions between doxepin, ?-cyclodextrin, and acetate during capillary isotachophoresis.  

PubMed

The capillary isotachophoresis (cITP) separation of the isomers of the tricyclic antidepressant doxepin using ?-cyclodextrin (?-CD) as a buffer additive is investigated by online microcoil NMR detection. Capillary electrophoresis (CE) is also used to determine the binding constant between the doxepin E and Z geometric isomers and ?-CD. Although the doxepin isomers could be easily baseline resolved by CE, their separation by cITP was more challenging due in part to the high concentration of doxepin after cITP-focusing. The use of online (1)H NMR detection allows observation of changes in doxepin dynamics due to formation of the ?-CD inclusion complex, changes in the fraction complexed and the intracapillary pH. It also provides novel experimental evidence that a weak complex between ?-CD and acetate contributes to its active transport from the leading electrolyte through the sample band to the trailing electrolyte in this cationic cITP separation. The results of these cITP-NMR experiments provide new mechanistic details about the interactions of the buffer counterion acetate with various components of the separation system and have important implications for other analyses based on formation of cyclodextrin inclusion complexes. PMID:22852806

Jones, Christopher J; Larive, Cynthia K

2012-08-21

264

Gaseous ammonia fluorescence probe based on cellulose acetate modified microstructured optical fiber  

Microsoft Academic Search

In this article, we report a novel fluorescent ammonia gas probe based on microstructured optical fiber (MOF) which is modified with eosin-doped cellulose acetate film. This probe was fabricated by liquid fluxion coating process. Polymer solution doped with eosin was directly inhaled into 18 array holes of MOF and then formed matrix film in them. The sensing properties of the

Lirong Peng; Xinghua Yang; Libo Yuan; Lili Wang; Enming Zhao; Fengjun Tian; Yanxin Liu

2011-01-01

265

EXTRACTION AND ELECTROSPINNING OF ZEIN EXTRACTED FROM CORN GLUTEN MEAL USING ACETIC ACID  

Technology Transfer Automated Retrieval System (TEKTRAN)

It has been demonstrated that zein fibers can be produced using the electrospinning technique. Fibers electrospun from acetic acid solution under suitable conditions provide fibers with a more consistent morphology (round 0.5-2.0 micro fibers) compared to fibers produced from aqueous ethanol soluti...

266

Parks, Buffer Zones, and Costly Enforcement  

Microsoft Academic Search

The reality of protected area management is that enforcing forest and park boundaries is costly and so most likely incomplete, due in part to the pressures exerted on the boundaries by local people who often have traditionally relied on the park resources. Buffer zones are increasingly being proposed and implemented to protect both forest resources and livelihoods. Developing a spatially-explicit

Elizabeth J. Z. Robinson; Heidi J. Albers

2006-01-01

267

Buffer placement improves when topography is considered  

Technology Transfer Automated Retrieval System (TEKTRAN)

Best Management Practices (BMPs) protect streams by excluding cattle from streambanks and by filtering the run-off flowing from animal heavy use areas like feeding and watering stations. Conservation standards recommend placing buffers and filter strips downslope from heavy use areas, but do not exp...

268

How tendons buffer energy dissipation by muscle  

PubMed Central

To decelerate the body and limbs, muscles actively lengthen to dissipate energy. During rapid energy-dissipating events, tendons buffer the work done on muscle by temporarily storing elastic energy, then releasing this energy to do work on the muscle. This elastic mechanism may reduce the risk of muscle damage by reducing peak forces and lengthening rates of active muscle. PMID:23873133

Roberts, Thomas J.; Konow, Nicolai

2013-01-01

269

Understanding the Science Behind Riparian Forest Buffers  

E-print Network

Understanding the Science Behind Riparian Forest Buffers: Resources for Virginia Landowners #12 Tech, 324 Cheatham Hall, Blacksburg, VA 24061; respectively Understanding the Science Behind Riparian* The riparian area is that area of land located immediately adjacent to streams, lakes, or other surface waters

Liskiewicz, Maciej

270

Virtual Memory o translation lookaside buffer (TLB)  

E-print Network

Virtual Memory o translation lookaside buffer (TLB) o cache o translation is called table walking o table walking done by MMU hardware o may take up to 4 memory reads (plus the actual access) for each virtual memory access o locality makes caching

Biagioni, Edoardo S.

271

Buffer layers on biaxially textured metal substrates  

DOEpatents

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

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

2001-01-01

272

Understanding the Science Behind Riparian Forest Buffers  

E-print Network

Riparian forests are found adjacent to streams, lakes, and other surface waters. They are characterizedUnderstanding the Science Behind Riparian Forest Buffers: Benefits to Communities and Landowners, Virginia Tech, 324 Cheatham Hall, Blacksburg, VA 24061 Understanding the Science Behind Riparian Forest

Liskiewicz, Maciej

273

Symmetric pH dependence of buffering power in giant fused cells from frog kidney proximal tubule.  

PubMed

This study measures the intrinsic buffering power (beta(i)) of giant fused cells from the proximal kidney tubule of the frog (Rana ridibunda) as a function of intracellular pH (pHi). We monitored pHi and transmembrane potential difference during acid or alkaline cell loading, achieved by removal of NH4Cl-containing solutions or CO2-HCO3(-)-equilibrated solutions, respectively, in the absence of extracellular Na+. Data were well fit by the equation for a single, monoprotic buffer with a maximum beta(i) at a pHi of 7.39 +/- 0.06 and a total buffer concentration of 30.7 +/- 1.6 mM (means +/- SD). From pHi measurements obtained during CO2-HCO3- exposure, we also calculated the buffering power afforded by the CO2-HCO3- pair, and we show its increasing contribution to total buffering power at increasing PCO2 and pHi. To our knowledge, this is the first report of a cell type in which intrinsic cell buffers can be adequately approximated as a single monoprotic buffer with a negative logarithm of apparent dissociation constant in the normal physiological range and essentially symmetric dependence on pHi in both acid and alkaline ranges. PMID:9140024

Bouyer, P; Cougnon, M; Thomas, S R; Hulin, P; Anagnostopoulos, T; Planelles, G

1997-04-01

274

Measurement of the rates of acetyl-CoA hydrolysis and synthesis from acetate in rat hepatocytes and the role of these fluxes in substrate cycling.  

PubMed Central

1. Acetyl-CoA hydrolysis, acetyl-CoA synthesis from acetate and several related fluxes were measured in rat hepatocytes. 2. In contrast with acetyl-CoA hydrolysis, most of the acetyl-CoA synthesis from acetate occurred in the mitochondria. 3. Acetyl-CoA hydrolysis was not significantly affected by 24 h starvation or (-)-hydroxycitrate. 4. In the cytoplasm there was a net flux of acetyl-CoA to acetate, and substrate cycling between acetate and acetyl-CoA in this compartment was very low, accounting for less than 0.1% of the total heat production by the animal. 5. A larger cycle, involving mitochondrial and cytoplasmic acetate and acetyl-CoA, may operate in fed animals, but would account for only approx 1% of total heat production. 6. It is proposed that the opposing fluxes of mitochondrial acetate utilization and cytoplasmic net acetate production may provide sensitivity, feedback and buffering, even when these fluxes are not linked to form a conventional substrate cycle. PMID:2396982

Crabtree, B; Gordon, M J; Christie, S L

1990-01-01

275

Amperometric titration of mercury with a stationary platinum electrode in stirred solutions.  

PubMed

Amperometric titration of mercury (in the range of 0-4 to 3.5 mg) has been carried out with 2-mercaptobenzoxazole with a stationary electrode in stirred solution in a sodium acetate-acetic acid medium. PMID:18959909

Bera, B C; Chakrabartty, M M; Bag, S P; Mallik, K L

1966-03-01

276

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

ERIC Educational Resources Information Center

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

Rajabzadeh, Massy

2012-01-01

277

A novel buffer system for separation of metal cations by capillary electrophoresis with indirect UV detection.  

PubMed

Generally, the buffers used for metal ion separations in capillary electrophoresis (CE) consist of a UV-active substance, pH-adjuster, and weak complexing reagent. This paper describes the successful separation of metal ions with a new buffer that contains no complexing reagent. Of several weakly basic compounds tested, 2-aminopyridine was selected as the most useful UV-active substance. It was used at a concentration of 15 mM with pH adjusted to 5.0 +/- 0.1 by acetic acid. The degree of protonation of the UV-active substance played an important role in detection. The stacking phenomenon was a significant contributor to efficiency in this buffer system, and water-diluted samples gave especially high efficiencies. When a 75-micron-i.d. fused-silica capillary was used, a separation efficiency of 1.8 x 10(5) was observed. Quantitative determinations of Ca2+, Mn2+, Zn2+, and Cd2+ were achieved with good linear calibration curves over the range of concentration from a few milligrams per liter to 100 mg/L. The detection limits were 0.2 mg/L for Ca2+, 0.4 mg/L for Mn2+ and Zn2+, and 0.6 mg/L for Cd2+, based on three times the baseline noise. PMID:9384787

Cheng, K; Nordmeyer, F R; Lamb, J D

1995-01-01

278

PCL-gelatin composite nanofibers electrospun using diluted acetic acid-ethyl acetate solvent system for stem cell-based bone tissue engineering.  

PubMed

Composite nanofibrous scaffolds with various poly(?-caprolactone) (PCL)/gelatin ratios (90:10, 80:20, 70:30, 60:40, 50:50 wt.%) were successfully electrospun using diluted acetic and ethyl acetate mixture. The effects of this solvent system on the solution properties of the composites and its electrospinning properties were investigated. Viscosity and conductivity of the solutions, with the addition of gelatin, allowed for the electrospinning of uniform nanofibers with increasing hydrophilicity and degradation. Composite nanofibers containing 30 and 40 wt.% gelatin showed an optimum combination of hydrophilicity and degradability and also maintained the structural integrity of the scaffold. Human mesenchymal stem cells (hMSCs) showed favorable interaction with and proliferation on, the composite scaffolds. hMSC proliferation was highest in the 30 and 40 wt.% gelatin containing composites. Our experimental data suggested that PCL-gelatin composite nanofibers containing 30-40 wt.% of gelatin and electrospun in diluted acetic acid-ethyl acetate mixture produced nanofiber scaffolds with optimum hydrophilicity, degradability, and bio-functionality for stem cell-based bone tissue engineering. PMID:24274102

Binulal, N S; Natarajan, Amrita; Menon, Deepthy; Bhaskaran, V K; Mony, Ullas; Nair, Shantikumar V

2014-01-01

279

Measurement of pH by NMR Spectroscopy in Concentrated Aqueous Fluoride Buffers  

PubMed Central

An NMR spectroscopic technique has been developed to give rapid, accurate pH measurements on tenth-milliliter samples of concentrated acidic aqueous solutions buffered by fluoride ion in the pH 1.5 – 4.5 range. The fluoride 19F chemical shift has been calibrated as a function of pH at 0.1 and 1.0 M concentration by reference to an internal 3-fluoropyridine standard. Subsequent measurements of fluoride buffer pH required no additives and only two NMR spectra in the presence of an external reference standard. PMID:21278857

Gerken, James B.

2010-01-01

280

Aqueous solution dispersement of carbon nanotubes  

NASA Technical Reports Server (NTRS)

Carbon nanotubes (CNTs) are dispersed in an aqueous buffer solution consisting of at least 50 weight percent water and a remainder weight percent that includes a buffer material. The buffer material has a molecular structure defined by a first end, a second end, and a middle disposed between the first and second ends. The first end is a cyclic ring with nitrogen and oxygen heteroatomes, the middle is a hydrophobic alkyl chain, and the second end is a charged group.

Kim, Jae-Woo (Inventor); Park, Cheol (Inventor); Choi, Sang H. (Inventor); Lillehei, Peter T. (Inventor); Harrison, Joycelyn S. (Inventor)

2011-01-01

281

A Buffer Material Optimal Design in the Radioactive Wastes Geological Disposal using the Satisficing Trade-off Method and the Self-organizing Map  

NASA Astrophysics Data System (ADS)

In this paper, we consider a multi-objective optimization method in order to obtain a preferred solution for the buffer material optimal design problem in the high-level radioactive wastes geological disposal. The buffer material optimal design problem is formulated as a constrained multi-objective optimization problem. Its Pareto optimal solutions are distributed evenly on whole bounds of the feasible region. Hence, we develop a search method to find a preferred solution easily for a decision maker from the Pareto optimal solutions which are distributed evenly and vastly. In the preferred solution search method, the visualization technique of a Pareto optimal solution set using the self-organizing map is introduced into the satisficing trade-off method which is the interactive method to obtain a Pareto optimal solution that satisfies a decision maker. We confirm the effectiveness of the preferred solution search method in the buffer material optimal design problem.

Okamoto, Takashi; Hanaoka, Yuya; Aiyoshi, Eitaro; Kobayashi, Yoko

282

Buffer layers on rolled nickel or copper as superconductor substrates  

DOEpatents

Buffer layer architectures are epitaxially deposited on biaxially-textured rolled substrates of nickel and/or copper and their alloys for high current conductors, and more particularly buffer layer architectures such as Y.sub.2 O.sub.3 /Ni, YSZ/Y.sub.2 O.sub.3 /Ni, Yb.sub.2 O.sub.3 /Ni, Yb.sub.2 O.sub.3 /Y.sub.2 O.sub.3 /Ni, Yb.sub.2 O.sub.3 /CeO.sub.2 /Ni, RE.sub.2 O.sub.3 /Ni (RE=Rare Earth), and Yb.sub.2 O.sub.3 /YSZ/CeO.sub.2 /Ni, Y.sub.2 O.sub.3 /Cu, YSZ/Y.sub.2 O.sub.3 /Cu, Yb.sub.2 O.sub.3 /Cu, Yb.sub.2 O.sub.3 /Y.sub.2 O.sub.3 /Cu, Yb.sub.2 O.sub.3 /CeO.sub.2 /Cu, RE.sub.2 O.sub.3 /Cu, and Yb.sub.2 O.sub.3 /YSZ/CeO.sub.2 /Cu. Deposition methods include physical vapor deposition techniques which include electron-beam evaporation, rf magnetron sputtering, pulsed laser deposition, thermal evaporation, and solution precursor approach, which includes chemical vapor deposition, combustion CVD, metal-organic decomposition, sol-gel processing, and plasma spray.

Paranthaman, Mariappan (Knoxville, TN); Lee, Dominic F. (Knoxville, TN); Kroeger, Donald M. (Knoxville, TN); Goyal, Amit (Knoxville, TN)

2000-01-01

283

Buffer optimization in network-on-chip through flow regulation  

E-print Network

buffers is an essential task since buffers are a major source of cost and power consumption. This paper proposes flow regulation and has defined a regulation spectrum as a means for system-on-chip architects to control delay and backlog bounds. The regulation is performed per flow for its peak rate and burstiness. However, many flows may have conflicting regulation requirements due to interferences with each other. Based on the regulation spectrum, this paper optimizes the regulation parameters aiming for buffer optimization. Three timing-constrained buffer optimization problems are formulated, namely, buffer size minimization, buffer variance minimization, and multiobjective optimization, which has both buffer size and variance as minimization objectives. Minimizing buffer variance is also important because it affects the modularity of routers and network interfaces. A realistic case study exhibits 62.8 % reduction of total buffers, 84.3 % reduction of total latency, and 94.4 % reduction on the sum of variances of buffers. Likewise, the experimental results demonstrate similar improvements in the case of synthetic traffic patterns. The optimization algorithm has low run-time complexity, enabling quick exploration of large design spaces. This paper concludes that optimal flow regulation can be a highly valuable instrument for buffer optimization in NoC designs. Index Terms—Buffer size, buffer variance, interior point method, network-on-chip (NoC), optimization problem. I.

Fahimeh Jafari; Zhonghai Lu; Axel Jantsch; Mohammad Hossein Yaghmaee

2010-01-01

284

Process for the preparation of vinyl acetate  

DOEpatents

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.

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

1998-01-01

285

Treatment of Pedophilia with Leuprolide Acetate  

Microsoft Academic Search

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

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

2002-01-01

286

Compatibility of buffered uranium carbides with tungsten.  

NASA Technical Reports Server (NTRS)

Results of compatibility tests between tungsten and hyperstoichiometric uranium carbide alloys run at 1800 C for 1000 and 2500 hours. These tests compared tungsten-buffered uranium carbide with tungsten-buffered uranium-zirconium carbide. The zirconium carbide addition appeared to widen the homogeneity range of the uranium carbide, making additional carbon available for reaction. Reaction layers could be formed by either of two diffusion paths, one producing UWC2, while the second resulted in the formation of W2C. UWC2 acts as a diffusion barrier for carbon and slows the growth of the reaction layer with time, while carbon diffusion is relatively rapid in W2C, allowing equilibrium to be reached in less than 2500 hours at a temperature of 1800 C.

Phillips, W. M.

1971-01-01

287

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...

288

Detecting buffer overflows using testcase synthesis and code instrumentation  

E-print Network

The research presented in this thesis aims to improve existing approaches to dynamic buffer overflow detection by developing a system that utilizes code instrumentation and adaptive test case synthesis to find buffer ...

Zhivich, Michael A

2005-01-01

289

Efficient buffer design algorithms for production line profit maximization  

E-print Network

A production line is a manufacturing system where machines are connected in series and separated by buffers. The inclusion of buffers increases the average production rate of the line by limiting the propagation of ...

Shi, Chuan, Ph. D. Massachusetts Institute of Technology

2012-01-01

290

Ultracompact optical buffers on a silicon chip  

Microsoft Academic Search

On-chip optical buffers based on waveguide delay lines might have significant implications for the development of optical interconnects in computer systems. Silicon-on-insulator (SOI) submicrometre photonic wire waveguides are used, because they can provide strong light confinement at the diffraction limit, allowing dramatic scaling of device size. Here we report on-chip optical delay lines based on such waveguides that consist of

Fengnian Xia; Lidija Sekaric; Yurii Vlasov

2007-01-01

291

Cd free buffer layers for solar cells  

Microsoft Academic Search

CdS layers obtained by chemical bath deposition (CBD) are usually used as buffer layer in chalcogenide based thin film solar cells. However, if good results are obtained, cadmium is toxic for the environment while the break of the physical vapour deposition (PVD) cycle, needed for CBD-CdS, constitutes a bottleneck in the process. Therefore many attempts are under way, all over

J. C. Bernede; M. Zoaeter; S. Marsillak; N. Barreauk; C. Oukld El Moctark; K. Benchouk; A. Khelil

2000-01-01

292

Facile pulping of lignocellulosic biomass using choline acetate.  

PubMed

Treating ground bagasse or Southern yellow pine in the biodegradable ionic liquid (IL), choline acetate ([Cho][OAc]), at 100°C for 24h led to dissolution of hemicellulose and lignin, while leaving the cellulose pulp undissolved, with a 54.3% (bagasse) or 34.3% (pine) reduction in lignin content. The IL solution of the dissolved biopolymers can be separated from the undissolved particles either by addition of water (20 wt% of IL) followed by filtration or by centrifugation. Hemicellulose (19.0 wt% of original bagasse, 10.2 wt% of original pine, containing 14-18 wt% lignin) and lignin (5.0 wt% of original bagasse, 6.0 wt% of original pine) could be subsequently precipitated. The pulp obtained from [Cho][OAc] treatment can be rapidly dissolved in 1-ethyl-3-methylimidazolium acetate (e.g., 17 h for raw bagasse vs. 7h for pulp), and precipitated as cellulose-rich material (CRM) with a lower lignin content (e.g., 23.6% for raw bagasse vs. 10.6% for CRM). PMID:24874879

Cheng, Fangchao; Wang, Hui; Chatel, Gregory; Gurau, Gabriela; Rogers, Robin D

2014-07-01

293

Enhanced dielectric properties from barium strontium titanate films with strontium titanate buffer layers  

NASA Astrophysics Data System (ADS)

In order to enhance the permittivity and tunability of the dielectric component, a thin film dielectric composite consisting of a radio frequency sputtered SrTiO3 (STO) buffer layer and metalorganic solution deposited Mg-doped BaxSr1-xTiO3 (Mg-BST) thin film overgrowth was developed using affordable industry standard processes and materials. The effect of the STO buffer layer thickness on the dielectric response of the heterostructure was investigated. Our results demonstrate that the composite film heterostructure, evaluated in the metal-insulator-metal configuration Pt/STO/Mg-BST/Pt on sapphire substrate, with the thinner (9-17 nm) STO buffer layers possessed enhanced permittivity (?r ˜ 491) with respect to the thicker 41 nm buffer layer (?r ˜ 360) and that of a control Mg-BST film without a STO buffer layer (?r ˜ 380). Additionally, the composite film with the thinner buffer layers were shown to have low losses (tan ? ˜ 0.02), low leakage characteristics (J = 7.0 × 10-9 A/cm2), high breakdown voltage (VBR > 10 V), a large grain microstructure (˜125 nm), and smooth pin-hole free surfaces. The enhanced permittivity of the composite dielectric film resulted from three major factors: (i) the template-effect of the thin STO buffer layer on the thicker Mg-BST over-layer film to achieve a large grain microstructure, (ii) the low viscosity of the metallo-organic solution deposition (MOSD) solution, which ensured heterogeneous nucleation of the Mg-BST overgrowth film on the surface of the STO buffer layer, and (iii) minimization of the low permittivity grain boundary phase (TiO2-x phase). The dielectric response of the BST can be explained using a thermodynamic model taking into account interlayer electrostatic and electromechanical interactions. Additionally, Mg doping of the BST enabled low loss and low leakage characteristics of the heterostructure. The large permittivity, low loss, low leakage characteristics, and defect free surfaces of the composite dielectric heterostructure promote tunable device miniaturization and hold the potential to enable enhanced electromagnetic coupling in ferromagnetic/high permittivity dielectric heterostructures, which in turn would facilitate the realization of integrated charge mediated voltage controlled magnetic radio frequency/microwave communication devices.

Cole, M. W.; Ngo, E.; Hubbard, C.; Hirsch, S. G.; Ivill, M.; Sarney, W. L.; Zhang, J.; Alpay, S. P.

2013-10-01

294

Synthesis and characterization of cellulose acetate from rice husk: eco-friendly condition.  

PubMed

Cellulose acetate was synthesized from rice husk by using a simple, efficient, cost-effective and solvent-free method. Cellulose was isolated from rice husk (RH) using standard pretreatment method with dilute alkaline and acid solutions and bleaching with 2% H2O2. Cellulose acetate (CA) was synthesized successfully with the yield of 66% in presence of acetic anhydride and iodine as a catalyst in eco-friendly solvent-free conditions. The reaction parameters were standardized at 80 °C for 300 min and the optimum results were taken for further study. The extent of acetylation was evaluated from % yield and the degree of substitution (DS), which was determined by (1)H NMR and titrimetrically. The synthesized products were characterized with the help modern analytical techniques like FT-IR, (1)H NMR, XRD, etc. and the thermal behavior was evaluated by TGA and DSC thermograms. PMID:25129753

Das, Archana M; Ali, Abdul A; Hazarika, Manash P

2014-11-01

295

Microbiological preservation of cucumbers for bulk storage using acetic acid and food preservatives.  

PubMed

Microbial growth did not occur when cucumbers were preserved without a thermal process by storage in solutions containing acetic acid, sodium benzoate, and calcium chloride to maintain tissue firmness. The concentrations of acetic acid and sodium benzoate required to ensure preservation were low enough so that stored cucumbers could be converted to the finished product without the need to wash out and discard excess acid or preservative. Since no thermal process was required, this method of preservation would be applicable for storing cucumbers in bulk containers. Acid tolerant pathogens died off in less than 24 h with the pH, acetic acid, and sodium benzoate concentrations required to assure the microbial stability of cucumbers stored at 30 degrees C. Potassium sorbate as a preservative in this application was not effective. Yeast growth was observed when sulfite was used as a preservative. PMID:19241560

Pérez-Díaz, I M; McFeeters, R F

2008-08-01

296

How Close Is Safe? Buffer Zone Development  

NSDL National Science Digital Library

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

297

Decoherence of trapped bosons by buffer gas scattering: What length scales matter?  

E-print Network

We ask and answer a basic question about the length scales involved in quantum decoherence: how far apart in space do two parts of a quantum system have to be, before a common quantum environment decoheres them as if they were entirely separate? We frame this question specifically in a cold atom context. How far apart do two populations of bosons have to be, before an environment of thermal atoms of a different species (`buffer gas') responds to their two particle numbers separately? An initial guess for this length scale is the thermal coherence length of the buffer gas; we show that a standard Born-Markov treatment partially supports this guess, but predicts only inverse-square saturation of decoherence rates with distance, and not the much more abrupt Gaussian behavior of the buffer gas's first-order coherence. We confirm this Born-Markov result with a more rigorous theory, based on an exact solution of a two-scatterer scattering problem, which also extends the result beyond weak scattering. Finally, however, we show that when interactions within the buffer gas reservoir are taken into account, an abrupt saturation of the decoherence rate does occur, exponentially on the length scale of the buffer gas's mean free path.

Lukas Gilz; Luis Rico-Pérez; James R. Anglin

2014-02-13

298

PERFORMANCE ANALYSIS OF NETWORKS OF OPEN ZERO-BUFFER  

E-print Network

to another continuously, without any waiting or buffering of work-in-process, since such waiting would result-in-process inventory and the product must never wait between two operations. As a last example, third generation mobile: A serial zero-buffer queuing network We are interested in zero-buffer multi-server general queueing

Cruz, Frederico

299

Groundwater nitrate following installation of a vegetated riparian buffer  

Technology Transfer Automated Retrieval System (TEKTRAN)

Buffers are often planted along streams to reduce nutrient loss from fields. The purpose of this study was to determine if a vegetated buffer could significantly decrease groundwater nitrate-nitrogen (NO3) concentrations. During 2000 and 2001, a three-part buffer was planted adjacent to a first-ord...

300

Use of GIS to Evaluate Riparian Buffers for Water Quality  

E-print Network

1 1 Use of GIS to Evaluate Riparian Buffers for Water Quality Improvements on a Campus Stream has little to no riparian buffers ­ The several transportation corridors are located throughout riparian buffer along the stream would significantly improved water quality within the stream

Clark, Shirley E.

301

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

PubMed Central

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

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

2013-01-01

302

Acetic acid detection threshold in synthetic wine samples of a portable electronic nose.  

PubMed

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

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

2013-01-01

303

Biogas Production through the Syntrophic Acetate-Oxidising Pathway  

E-print Network

retention time OLR Organic loading rate PCR Polymerase chain reaction qPCR Quantitative polymerase chain reaction RNA Ribonucleic acid SAO Syntrophic acetate oxidation SAOB Syntrophic acetate-oxidising bacteria

304

21 CFR 582.5892 - a-Tocopherol acetate.  

Code of Federal Regulations, 2013 CFR

... ANIMAL 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...

2013-04-01

305

21 CFR 582.5892 - a-Tocopherol acetate.  

Code of Federal Regulations, 2011 CFR

... ANIMAL 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...

2011-04-01

306

21 CFR 582.5892 - a-Tocopherol acetate.  

Code of Federal Regulations, 2012 CFR

... ANIMAL 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...

2012-04-01

307

Influence of Amino Acids, Buffers, and pH on the ?-Irradiation-Induced Degradation of Alginates.  

PubMed

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

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

2014-12-01

308

Solutions : WtPercentToMolarity (4 Variations)  

NSDL National Science Digital Library

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

309

Gold-catalyzed cyclization of allenyl acetal derivatives  

PubMed Central

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

Vasu, Dhananjayan; Pawar, Samir Kundlik

2013-01-01

310

Dissolution control of mg by cellulose acetate-polyelectrolyte membranes.  

PubMed

Cellulose acetate (CA)-based membranes are used for Mg dissolution control: the permeability of the membrane is adjusted by additions of the polyelectrolyte, poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA). Spin-coated films were characterized with FT-IR, and once exposed to an aqueous solution the film distends and starts acting as a membrane which controls the flow of ions and H2 gas. Electrochemical measurements (linear sweep voltammograms, open-circuit potential, and polarization) show that by altering the CA:PDMAEMA ratio the dissolution rate of Mg can be controlled. Such a control over Mg dissolution is crucial if Mg is to be considered as a viable, temporary biomedical implant material. Furthermore, the accumulation of corrosion products between the membrane and the sample diminishes the undesirable effects of high local pH and H2 formation which takes place during the corrosion process. PMID:25426707

Yliniemi, Kirsi; Wilson, Benjamin P; Singer, Ferdinand; Höhn, Sarah; Kontturi, Eero; Virtanen, Sannakaisa

2014-12-24

311

Isothermal decomposition of ?-irradiated samarium acetate  

NASA Astrophysics Data System (ADS)

Isothermal decomposition of un-irradiated and pre-?-irradiated samarium acetate has been investigated at different temperatures between 613 and 633 K. Irradiation was observed to enhance the rate of decomposition without modifying the mechanism of thermal decomposition. Thermal decomposition of samarium acetate has been shown to proceed by two-dimensional phase-boundary reaction both for un-irradiated and pre-?-irradiated samples. The enhancement of the decomposition was found to increase with an increase in the ?-ray dose applied to the sample and may be attributed to an increase in point defects and formation of additional nucleation centers generated in the host lattice. Thermodynamic values of the main decomposition process were calculated and evaluated.

Mahfouz, R. M.; Monshi, M. A. S.; Alshehri, S. M.; Abd El-Salam, N. M.

2000-10-01

312

Lithium acetate transformation of yeast Maitreya Dunham August 2004  

E-print Network

Lithium acetate transformation of yeast Maitreya Dunham August 2004 Original protocol from Katja until the OD600 is around 0.7-0.8 (~7 hours). Spin down the cells. Resuspend in 5 ml lithium acetate mix. Spin. Resuspend in 0.5 ml lithium acetate mix. Transfer to an eppendorf tube. Incubate 60 minutes

Dunham, Maitreya

313

Formation of acetic acid from cellulosic substrates by Fusarium oxysporum  

Microsoft Academic Search

Four strains of Fusarium oxysporum and a strain of Monilia brunnae were screened for their ability to convert cellulosic substrates into ethanol\\/acetic acid. These strains were found to utilize cellulose and produce extracellular cellulases. However, only F. oxysporum 841 was found to convert glucose, xylose, and cellulose into ethanol and acetic acid as major end-products under microaerobic conditions. Acetic acid

P. K. R. Kumar; Ajay Singh; K. Schiigerl

1991-01-01

314

Concentrated Flow through a Riparian Buffer: A Case Study  

NASA Astrophysics Data System (ADS)

Riparian buffers are often used for in-situ treatment of agricultural runoff. Although the benefits of riparian buffers are well recongized, concentration of flow can restrict the efficiency of contaminant removal. This study evaluates flow concentration at a agricultural site near Manhattan, Kansas. Manual and automated GIS analyses of a high-resolution digital elevation model were used to determine the fraction of runoff contributing to each buffer segment. Subsequent simulation of the system in WEPP (Water Erosion and Prediction Project) demonstrates the extent to which flow concentration affects buffer efficiency. Recommendations are presented for the design of adaptive-width buffers.

Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

2005-05-01

315

Functional Properties of Extruded Starch Acetate Blends  

Microsoft Academic Search

Starch acetate, with degree of substitution of 2, was blended with 0, 7.5 and 15% polylactic acid (PLA), Eastar Bio Copolyester 14766 (EBC) or Mater-Bi ZF03U (MBI) and 10%, 13%, or 16% (d.b.) ethanol and twin-screw extruded at 160°C barrel temperature. Physical characteristics of the extrudates, such as radial expansion ratio, unit and bulk densities, and of the mechanical properties,

J. Guan; Q. Fang; M. A. Hanna

2004-01-01

316

Ammonia permeability of a cellulose acetate membrane  

Microsoft Academic Search

A mechanism is proposed for ammonia transport across a cellulose acetate membrane. The transport is shown to have a sorption\\u000a character, with the formation of hydrogen bonds between ammonia molecules and the polymer. Our experiments demonstrate that\\u000a the membrane can be regenerated in the course of gas separation. The ideal separation factors in the ammonia-nitrogen and\\u000a ammonia-hydrogen systems are determined.

I. V. Vorotyntsev; P. N. Drozdov; N. V. Karyakin

2006-01-01

317

Acetic acid bacteria as enantioselective biocatalysts  

Microsoft Academic Search

Acetic acid bacteria (five strains of Acetobacter and five strains of Gluconobacter) were used for the biotransformation of different primary alcohols (2-chloropropanol and 2-phenylpropanol) and diols (1,3-butandiol, 1,4-nonandiol and 2,3-butandiol). Most of the tested strains efficiently oxidized the substrates. 2-Chloropropanol and 1,3-butandiol were oxidized with good rates and low enantioselectivity (enantiomeric excess=18–46% of the S-acid), while microbial oxidation of 2-phenylpropanol

A Romano; R Gandolfi; P Nitti; M Rollini; F Molinari

2002-01-01

318

Nonenzymatic phosphorylation of acetate by carbamyl phosphate  

NASA Astrophysics Data System (ADS)

It is found that carbamyl phosphate is an efficient condensing agent for acetate and hydroxylamine in the presence of Be2+ and Al3+. The reaction has an optimum at pH 4 and is completed within 30 min. The yield of hydroxamate formation reaches 30% (based on initial carbamyl phosphate). Acetylphosphate as the intermediary product of this reaction was identified by P-NMR spectroscopy.

Saygin, Ömer

1983-03-01

319

Study of the Photodegradation Process of Vitamin E Acetate by Optical Absorption, Fluorescence, and Thermal Lens Spectroscopy  

NASA Astrophysics Data System (ADS)

The stability of vitamin E acetate exposed to ultraviolet (UV) light was studied using three spectroscopic methods. An ethanol solution of vitamin E acetate was treated with either UVC light (254 nm) or UVA light (366 nm) during a period of 10 min followed by a study of UV-Vis optical absorption, then by fluorescence spectroscopy excitation by UV radiation at either 290 nm or 368 nm and, finally the solution was studied by thermal lens spectroscopy. Immediately, the same solution of vitamin E acetate was subjected to the UV irradiation process until completion of six periods of irradiation and measurements. UVC light treatment induced the appearance of a broad absorption band in the range of 310 nm to 440 nm with maximum absorbance at 368 nm, which progressively grew as the time of the exposure to UVC light increases. In contrast, UVA light treatment did not affect the absorption spectra of vitamin E acetate. Fluorescence spectra of the vitamin E acetate (without UV light treatment) showed no fluorescence when excited with 368 nm while exciting with 290 nm, an intense and broad emission band (300 nm to 440 nm) with a maximum at 340 nm appeared. When vitamin E acetate was treated with UVC light, this emission band progressively decreased as the time of the UVC light irradiation grew. No signal from UV-untreated vitamin E acetate could be detected by the thermal lens method. Interestingly, as the time of the UVC light treatment increased, the thermal lens signal progressively grew. Additional experiments performed to monitor the time evolution of the process during continuous UVC treatment of the vitamin E acetate using thermal lens spectroscopy exhibited a progressive increase of the thermal lens signal reaching a plateau at about 8000 s. This study shows that the vitamin E acetate is stable when it is irradiated with UVA light, while the irradiation with UVC light induces the formation of photodegradation products. Interestingly, this photodegradation process using the study of the thermal lens effect could be followed closely even though poor absorption of the photodegraded product of the vitamin E acetate was observed at the laser wavelength used. As the thermal lens method allowed for accurate monitoring of the extent of photodegradation of the vitamin E acetate, this study opens the photodegradation process as a new application to be added to the recent applications of thermal lens spectroscopy in chemical analysis.

Tiburcio-Moreno, J. A.; Marcelín-Jiménez, G.; Leanos-Castaneda, O. L.; Yanez-Limon, J. M.; Alvarado-Gil, J. J.

2012-11-01

320

Effect of ethyl acetate on carbohydrate components and crystalline structure of pulp produced in aqueous acetic acid pulping  

Microsoft Academic Search

The aim of this study was to investigate the changes in carbohydrate components and the crystalline structure in hemp bast\\u000a fibers by adding ethyl acetate to acetic acid\\/water pulping processes. It was found that ethyl acetate added to acetic acid\\/water\\u000a process had a positive effect on yield, viscosity and carbohydrate components in pulp. It was assumed that the delignification\\u000a ratio

Esat Gümü?kaya; Mustafa Usta; Mualla Balaban Uçar

2009-01-01

321

Evidence for a transition state analog, MgADP-aluminum fluoride-acetate, in acetate kinase from Methanosarcina thermophila.  

PubMed

Aluminum fluoride has become an important tool for investigating the mechanism of phosphoryl transfer, an essential reaction that controls a host of vital cell functions. Planar AlF(3) or AlF(4)(-) molecules are proposed to mimic the phosphoryl group in the catalytic transition state. Acetate kinase catalyzes phosphoryl transfer of the ATP gamma-phosphate to acetate. Here we describe the inhibition of acetate kinase from Methanosarcina thermophila by preincubation with MgCl(2), ADP, AlCl(3), NaF, and acetate. Preincubation with butyrate in place of acetate did not significantly inhibit the enzyme. Several NTPs can substitute for ATP in the reaction, and the corresponding NDPs, in conjunction with MgCl(2), AlCl(3), NaF, and acetate, inhibit acetate kinase activity. Fluorescence quenching experiments indicated an increase in binding affinity of acetate kinase for MgADP in the presence of AlCl(3), NaF, and acetate. These and other characteristics of the inhibition indicate that the transition state analog, MgADP-aluminum fluoride-acetate, forms an abortive complex in the active site. The protection from inhibition by a non-hydrolyzable ATP analog or acetylphosphate, in conjunction with the strict dependence of inhibition on the presence of both ADP and acetate, supports a direct in-line mechanism for acetate kinase. PMID:11960978

Miles, Rebecca D; Gorrell, Andrea; Ferry, James G

2002-06-21

322

Overview on mechanisms of acetic acid resistance in acetic acid bacteria.  

PubMed

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. PMID:25575804

Wang, Bin; Shao, Yanchun; Chen, Fusheng

2015-02-01

323

Pervaporation separation of water-acetic acid mixtures through poly(vinyl alcohol) membranes crosslinked with glutaraldehyde  

Microsoft Academic Search

Poly(vinyl alcohol) (PVA) membranes crosslinked with glutaraldehyde (GA) were prepared by a solution method for the pervaporation separation of acetic acid-water mixtures. In the solution method, dry PVA films were crosslinked by immersion for 2 days at 40°C in reaction solutions which contained different contents of GA, acetone and a catalyst, HCl. In order to fabricate the crosslinked PVA membranes

Choong-Kyun Yeom; Kew-Ho Lee

1996-01-01

324

The potential of a phyllosilicate (Palabora vermiculite) as buffer in dairy cattle diets.  

PubMed

Four rumen-fistulated Holstein cows were used to determine the ability of vermiculite to alter rumen fermentation, rumen fluid dilution rate, milk production, and nutrient utilization in a 4 x 4 Latin square experiment. Treatments consisted of 1) basal diet (70% concentrate:30% Eragrostis curvula hay), 2) basal + .6% NaHCO3 + 1.8% vermiculite, 3) basal + 1.2% NaHCO3, and 4) basal + 3.6% vermiculite. Feed intake and milk production were not affected, but the NaHCO3 treatments tended to increase milk fat production. The 1.2% NaHCO3 treatment increased rumen pH and fluid dilution rate, decreased molar percent propionate, and increased acetate:propionate ratio. Rumen NH3 N was not affected. Milk yield (kg/d) and milk fat (%) for the treatments were 1) 19.3, 3.33; 2) 19.4, 3.59; 3) 19.8, 3.62; and 4) 18.7, 3.32. Rumen fluid pH, dilution rate (%/h), and acetate:propionate ratio were 1) 5.75, 10.9, 2.08; 2) 5.89, 11.5, 2.16; 3) 5.95, 12.1, 2.38; and 4) 5.80, 11.6 and 1.82. Treatments had little effect on nutrient digestibilities and serum mineral concentrations. Vermiculite did not show any promise as a buffer but NaHCO3 proved to be an effective buffer in diets based on Eragrostis hay and 70% concentrate diets. PMID:2545754

Erasmus, L J; Prinsloo, J

1989-04-01

325

Methylenetetrahydrofolate dehydrogenase assay microplate format Stock solutions  

E-print Network

Methylenetetrahydrofolate dehydrogenase assay ­ microplate format Stock solutions 2X buffer: 166 m. Store on ice. This yields a 1 mM CH2-THF stock in 100 mM 2-mercaptoethanol. Final volume in each well

326

NCI-Frederick PHL - Fixatives and Solutions  

Cancer.gov

Services Price List Courier Services & Shipment Procedures Scheduling Contact Information Related Links Establishing an Account PHL Forms PHL Portal Fixatives and Solutions Routine fixatives: 10% Neutral Buffered Formalin (NBF) 37 - 40% Formaldehyde………………………………………1000mL distilled

327

Near-surface ion distribution and buffer effects during electrochemical reactions.  

PubMed

The near-surface ion distribution at the solid-liquid interface during the Hydrogen Oxidation Reaction (HOR)/Hydrogen Evolution Reaction (HER) on a rotating platinum disc electrode is demonstrated in this work. The relation between reaction rate, mass transport and the resulting surface pH-value is used to theoretically predict cyclic voltammetry behaviour using only thermodynamic and diffusion data obtained from the literature, which were confirmed by experimental measurements. The effect of buffer addition on the current signal, the surface pH and the ion distribution is quantitatively described by analytical solutions and the fragility of the surface pH during reactions that form or consume H(+) in near-neutral unbuffered solutions or poorly buffered media is highlighted. While the ideal conditions utilized in this fundamental study cannot be directly applied to real scenarios, they do provide a basic understanding of the surface pH concept for more complex heterogeneous reactions. PMID:21837326

Auinger, Michael; Katsounaros, Ioannis; Meier, Josef C; Klemm, Sebastian O; Biedermann, P Ulrich; Topalov, Angel A; Rohwerder, Michael; Mayrhofer, Karl J J

2011-09-28

328

Convergent Geometry Foam Buffered Direct Drive Experiments*  

NASA Astrophysics Data System (ADS)

A serious concern for directly driven ICF implosions is the asymmetry imparted to the capsule by laser drive non-uniformities, particularly the ``early time imprint'' remaining despite the use of random phase plates and smoothing with spectral dispersion. The use of a foam buffer has been proposed as a means to reduce this imprint. Two types of convergent geometry tests of the technique to correct static nonuniformities have been studied to date; cylindrical implosions at the Trident and Vulcan lasers, and spherical implosions at the NOVA laser, all using 527 nm laser drive. Cylindrical implosions used end on x-ray backlighter imaging of inner surface disruption due an intentional hole in the drive footprint, using 50 mg/cc acyrlate foam with a thin Au preheat layer. Spherical implosions used 50 mg/cc polystyrene foam plus Au to study yield and imploded core symmetry of capsules with and without a foam buffer, in comparison to ``clean 1D'' calculations. For thick enough layers, all cases showed improvement. Details of the experiments and theoretical unpinnings will be shown. *Work performed under US DOE Contract No. W-7405-Eng-36.

Watt, R. G.; Wilson, D. C.; Hollis, R. V.; Gobby, P. L.; Chrien, R. E.; Mason, R. J.; Kopp, R. A.; Willi, O.; Iwase, A.; Barringer, L. H.; Gaillard, R.; Kalantar, D. H.; Lerche, R. A.; MacGowan, B.; Nelson, M.; Phillips, T.; Knauer, J. P.; McKenty, P. W.

1996-11-01

329

Gas migration in MX80 buffer bentonite  

SciTech Connect

Controlled flow-rate gas injection experiments have been performed on pre-compacted samples of KBS-3 specification Mx80 buffer bentonite using helium as a safe replacement for hydrogen. By simultaneously applying a confining pressure and backpressure, specimens were isotropically-consolidated and fully water-saturated under pre-determined effective stress conditions, before injecting gas using a syringe pump. Ingoing and outgoing gas fluxes were monitored. All tests exhibited a conspicuous threshold pressure for breakthrough, somewhat larger than the sum of the swelling pressure and the backpressure. All tests showed a post-peak negative transient leading to steady-state gas flow. Using a stepped history of flow rate, the flow law was shown to be nonlinear. With the injection pump stationary (i.e., zero applied flow rate), gas pressure declined with time to a finite value. When gas flow was reestablished, the threshold value for gas breakthrough was found to be significantly lower than in virgin clay. There is strong evidence to suggest that the capillary pressure for the penetration of interparticle pore space of buffer bentonite is of such a magnitude that normal two-phase flow is impossible. Gas entry and breakthrough is therefore accompanied by the development of microcracks which propagate through the clay from gas source to sink. The experiments suggest that these pathways open under high gas pressure conditions and partially close if gas pressure falls, providing a possible explanation of the nonlinearity of the flow law.

Horseman, S.T.; Harrington, J.F. [British Geological Survey, Nottingham, (United Kingdom). Fluid Process Group; Sellin, P. [Svensk Kaerbraenslehantering AB, Stockholm (Sweden)

1997-12-31

330

A novel cadmium free buffer layer for Cu(In,Ga)Se 2 based solar cells  

Microsoft Academic Search

Solar cells based on Cu(In,Ga)Se2 were prepared replacing the “standard buffer layer” CdS with a Inx(OH,S)y thin film. The film is deposited in a chemical bath (CBD) process using an aqueous solution containing InCl3 and thioacetamide. X-ray photoemission spectroscopy measurements were performed in order to characterize the growth kinetics and the chemical composition. The influence of different concentrations of InCl3

Dimitri Hariskos; Martin Ruckh; Ulfert Rühle; Thomas Walter; Hans Werner Schock; Jonas Hedström; Lars Stolt

1996-01-01

331

ZnS/Zn(O,OH)S-based buffer layer deposition for solar cells  

DOEpatents

The invention provides CBD ZnS/Zn(O,OH)S and spray deposited ZnS/Zn(O,OH)S buffer layers prepared from a solution of zinc salt, thiourea and ammonium hydroxide dissolved in a non-aqueous/aqueous solvent mixture or in 100% non-aqueous solvent. Non-aqueous solvents useful in the invention include methanol, isopropanol and triethyl-amine. One-step deposition procedures are described for CIS, CIGS and other solar cell devices.

Bhattacharya, Raghu N. (Littleton, CO)

2009-11-03

332

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

NASA Astrophysics Data System (ADS)

Very uniform and transparent zinc oxide thin films doped with aluminium and indium were fabricated by the dip-coating technique using solutions prepared by the ethanolamine method. As starting materials, zinc acetate and zinc n-propoxide were used. Zinc acetate and propoxide are soluble in Pr(sup i)OH in the presence of diethanolamine, although they are hardly soluble without the amine. The prepared solution were very stable and suitable for dip-coating. Zinc oxide was crystallized by heating above 500 C, and doping of aluminium and indium retarded the crystallization. The electrical resistivity of the film was decreased by doping with aluminium and indium. The lowest resistivity of 2 x 10(sup - 2) Omega cm was obtained by post-coating treatment in a nitrogen atmosphere.

Ohya, Y.; Saiki, H.; Takahashi, Y.

1994-08-01

333

Growth and characterization of pure and doped bis thiourea zinc acetate: Semiorganic nonlinear optical single crystals  

Microsoft Academic Search

Metal–organic coordination complex single crystals bis thiourea zinc acetate (BTZA) and Cd2+ doped BTZA have been synthesized and grown successfully by slow-cooling technique from their aqueous solutions. Single crystals of pure and Cd2+ doped BTZA with dimensions of 35×4×2mm3 and 10×5×6mm3, respectively were obtained with well defined morphology. The as grown single crystals are characterized by single crystal XRD studies

M. Lydia Caroline; S. Vasudevan

2009-01-01

334

Structural, spectral, thermal, dielectric, mechanical and optical properties of urea l-alanine acetate single crystals  

Microsoft Academic Search

A new organic nonlinear optical crystal, urea l-alanine acetate (ULAA) has been grown by solution growth using slow cooling technique with the vision to improve the properties of the l-alanine crystals. Urea and l-alanine material were mixed in the molar ratio 1:4. Solubility and metastable zone width were determined. Single crystal XRD analyses revealed that the crystal lattice of ULAA

D. Jaikumar; S. Kalainathan; G. Bhagavannarayana

2010-01-01

335

Methane production from rice straw pretreated by a mixture of acetic–propionic acid  

Microsoft Academic Search

Rice straw was treated with a mixed solution of acetic acid and propionic acid to enhance its biodegradability. The effect of acid concentration, pretreatment time, and the ratio of solid to liquid on the delignification performance of rice straw were investigated. It was found that the optimal conditions for hydrolysis were 0.75mol\\/L acid concentration, 2h pretreatment time and 1:20 solid

Rui Zhao; Zhenya Zhang; Ruiqin Zhang; Miao Li; Zhongfang Lei; Motoo Utsumi; Norio Sugiura

2010-01-01

336

Cellulose acetate-coated ?-alumina ceramic composite tubular membranes for wastewater treatment  

Microsoft Academic Search

A novel method was developed to reduce the pore size of microporous ceramic tubular membranes by coating their inner surfaces using cellulose acetate solution forming a thin coating of ~35 ?m. Three tubular membrane configurations viz., 1-channel, 7-channel and 19-channel, hollow tubular having an identical pore size of 1.2 ?m and apparent porosity of 35 vol.% were tested for pollutants

S. K. Nataraj; S. Roy; M. B. Patil; M. N. Nadagouda; W. E. Rudzinski; T. M. Aminabhavi

2011-01-01

337

Quantitative precipitation of large amounts of sodium as sodium zinc uranyl acetate and its determination by an indirect complexometric method.  

PubMed

Up to 40 mg of sodium can be quantitatively precipitated as sodium zinc uranyl acetate if enough reagent of appropriate composition is added to make the concentrations of zinc and uranium in the mother liquor at least 1.25 and 0.14M respectively. In practice, the reagent solution contains 100 g of uranyl acetate and 300 g of zinc acetate per litre and the volume added (ml) must be at least 15 times that of the solution to which it is added or 1.5 times the number of mg of sodium present, whichever is the greater. The triple salt can then be dissolved in water and the zinc selectively titrated with EDTA at pH 5.3, with Xylenol Orange as indicator. The uranium is masked with ammonium fluoride. Most constituents of ceramics and other silicates, including barium, strontium, magnesium, potassium, sulphate, phosphate and arsenate, do not interfere. PMID:18962497

Sinha, B C; Roy, S K

1979-07-01

338

The Multimission Image Processing Laboratory's virtual frame buffer interface  

NASA Technical Reports Server (NTRS)

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.

Wolfe, T.

1984-01-01

339

Small-angle neutron scattering study of pH dependence of the liquid structure factor of concentrated solutions of eye lens gamma-B crystallin  

NASA Astrophysics Data System (ADS)

We are evaluating the pH dependence of the liquid structure of aqueous solutions of the eye lens protein, gammaB crystallin, near its critical point for liquid-liquid phase separation, to help evaluate the influence of protein charge on the phase separation. We have obtained small-angle neutron scattering data from gammaB crystallin solutions at pH 6.4, 7.1 and 7.4 in a 0.1 M sodium phosphate buffer, and at pH 4.5 in a 0.020M sodium acetate buffer, all in D2O. Protein concentrations ranged from 6 to 260 mg protein/ml solution and the scattering vector magnitude (q) ranged from 0.004 to 0.45 inverse Angstroms. At pH 6.4 to 7.4 liquid structure factors vs. concentration and temperature near the cloud point for liquid-liquid phase separation are well represented, in general, by the Baxter sticky sphere model. In contrast, at pH 4.5, concentrated gammaB shows a very different liquid structure indicating highly repulsive interprotein interactions, consistent with both high net protein charge and reduced screening.

Desmond, Kenneth; Thurston, George; Stradner, Anna; Schurtenberger, Peter

2006-03-01

340

GaN Growth Using GaN Buffer Layer  

Microsoft Academic Search

High-quality gallium nitride (GaN) film was obtained for the first time using a GaN buffer layer on a sapphire substrate. An optically flat and smooth surface was obtained over a two-inch sapphire substrate. Hall measurement was performed on GaN films grown with a GaN buffer layer as a function of the thickness of the GaN buffer layer. For the GaN

Shuji Nakamura

1991-01-01

341

Inhibition of enamel demineralization by buffering effect of S-PRG filler-containing dental sealant.  

PubMed

The buffering capacity and inhibitory effects on enamel demineralization of two commercially available dental sealants were evaluated in this study. The effects of filler particles were also examined. Disks of enamel and cured sealant materials of BeautiSealant (silica or S-PRG filler) or Teethmate F-1 were incubated in lactic acid solutions (pH 4.0) for 1-6 d. The pH changes and amounts of ions released in the solutions were assessed, and enamel surfaces were observed using a scanning electron microscope. The pH of the solution with BeautiSealant (S-PRG filler) was neutralized from pH 4.0 to pH 6.1 (after incubation for 1 d) and from pH 4.0 to pH 6.7 (after incubation for 6 d). In addition, no release of calcium ions was detected and the enamel surface was morphologically intact in scanning electron microscopy images. However, the pH of the solution with Teethmate F-1 remained below pH 4.0 during incubation from days 1 to 6. Calcium release was increased in solutions up to and after 6 d of incubation. Scanning electron microscopy images showed that the structures of hydroxyapatite rods were exposed at the specimen surfaces as a result of demineralization. Ions released from S-PRG filler-containing dental sealant rapidly buffered the lactic acid solution and inhibited enamel demineralization. PMID:24372898

Kaga, Masayuki; Kakuda, Shinichi; Ida, Yusuke; Toshima, Hirokazu; Hashimoto, Masanori; Endo, Kazuhiko; Sano, Hidehiko

2014-02-01

342

Stable acetate production in extreme-thermophilic (70°C) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens.  

PubMed

The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in extreme-thermophilic (70°C) mixed culture fermentation. The continuous stirred tank reactor (CSTR) was stable operated during 100 days, in which acetate accounted for more than 90% of metabolites in liquid solutions. The yields of acetate, methane and biomass in CSTR were 1.5 ± 0.06, 1.0 ± 0.13 and 0.4 ± 0.05 mol/mol glucose, respectively, close to the theoretical expected values. The CSTR effluent was stable and no further conversion occurred when incubated for 14 days in a batch reactor. In fed-batch experiments, acetate could be produced up to 34.4 g/L, significantly higher than observed in common hydrogen producing fermentations. Acetate also accounted for more than 90% of soluble products formed in these fed-batch fermentations. The microbial community analysis revealed hydrogenotrophic methanogens (mainly Methanothermobacter thermautotrophicus and Methanobacterium thermoaggregans) as 98% of Archaea, confirming that high temperature will select hydrogenotrophic methanogens over aceticlastic methanogens effectively. This work demonstrated a potential application to effectively produce acetate as a value chemical and methane as an energy gas together via mixed culture fermentation. PMID:24920064

Zhang, Fang; Zhang, Yan; Ding, Jing; Dai, Kun; van Loosdrecht, Mark C M; Zeng, Raymond J

2014-01-01

343

Natriuretic peptides buffer renin-dependent hypertension.  

PubMed

The renin-angiotensin-aldosterone system and cardiac natriuretic peptides [atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP)] are opposing control mechanisms for arterial blood pressure. Accordingly, an inverse relationship between plasma renin concentration (PRC) and ANP exists in most circumstances. However, PRC and ANP levels are both elevated in renovascular hypertension. Because ANP can directly suppress renin release, we used ANP knockout (ANP(-/-)) mice to investigate whether high ANP levels attenuate the increase in PRC in response to renal hypoperfusion, thus buffering renovascular hypertension. ANP(-/-) mice were hypertensive and had reduced PRC compared with that in wild-type ANP(+/+) mice under control conditions. Unilateral renal artery stenosis (2-kidney, 1-clip) for 1 wk induced similar increases in blood pressure and PRC in both genotypes. Unexpectedly, plasma BNP concentrations in ANP(-/-) mice significantly increased in response to two-kidney, one-clip treatment, potentially compensating for the lack of ANP. In fact, in mice lacking guanylyl cyclase A (GC-A(-/-) mice), which is the common receptor for both ANP and BNP, renovascular hypertension was markedly augmented compared with that in wild-type GC-A(+/+) mice. However, the higher blood pressure in GC-A(-/-) mice was not caused by disinhibition of the renin system because PRC and renal renin synthesis were significantly lower in GC-A(-/-) mice than in GC-A(+/+) mice. Thus, natriuretic peptides buffer renal vascular hypertension via renin-independent effects, such as vasorelaxation. The latter possibility is supported by experiments in isolated perfused mouse kidneys, in which physiological concentrations of ANP and BNP elicited renal vasodilatation and attenuated renal vasoconstriction in response to angiotensin II. PMID:24717731

Demerath, Theo; Staffel, Janina; Schreiber, Andrea; Valletta, Daniela; Schweda, Frank

2014-06-15

344

Plasmacatalytic removal of lead acetate assisted by precipitation.  

PubMed

The Gliding Arc Discharge (GAD) is an efficient non-thermal plasma technique able to degrade organic compounds dispersed in water at atmospheric pressure. The degradation of the organometallic lead acetate (PbAc) in aqueous solution was performed by two distinct plasmageneous processes: GAD and GAD/TiO2. The global oxidation of the organic matter was followed by Chemical Oxygen Demand (COD) and the mineralization was determined by the Total Organic Carbon (TOC). The Pb(2+) ions released during the degradation process were measured by Atomic Absorption Spectroscopy (AAS). For 2h of GAD treatment, the degradation rate of PbAc (10mM) reached 83% and for the same duration of GAD/TiO2 process ([TiO2]=1gL(-1)), it reached 93%. The release of Pb(2+) ions in the solution was respectively of 95% and 57% for GAD and GAD/TiO2 processes. The released Pb(2+) ions were removed by precipitation process in a basic medium at pH=11.1. A reaction mechanism was proposed to explain the PbAc molecule degradation and the Pb(2+) elimination. PMID:24462087

Haddou, Nabila; Ghezzar, Mouffok Redouane; Abdelmalek, Fatiha; Ognier, Stéphanie; Martel, Marc; Addou, Ahmed

2014-07-01

345

Immunotoxicity of trenbolone acetate in Japanese quail  

USGS Publications Warehouse

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.

Quinn, M.J.; McKernan, M.; Lavoie, E.T.; Ottinger, M.A.

2007-01-01

346

Atmospheric formic and acetic acids in Venezuela  

NASA Astrophysics Data System (ADS)

Gas, phase and rain concentrations of HCOOH and CH 3COOH have been measured at various sites in the savannah climatic region, a cloud forest site and a coastal site in Venezuela. Gas phase and rain water were sampled using the aqueous scrubber technique and a wet only collector, respectively. Analyses were made by ion chromatography. The results indicate that formic and acetic acids are important components of the Venezuelan atmosphere. They are homogeneously distributed, suggesting a widespread source. Boundary layer concentrations during the dry season (HCOOH, 1.8 ppbv; CH 3COOH, 1.25 ppbv) are higher than in the wet season (HCOOH, 1.0 ppbv; CH 3COOH, 0.7 ppbv), mainly due to a longer lifetime of the acid during the dry season (˜6 days) compared with the wet season (˜2 days). The overall concentrations in rain are 7.0 and 4.0 ?M for formic and acetic acids, respectively. The estimated annual total depositions are: HCOOH, 17 mmol m -2 yr -1 and CH 3COOH,10 mmol m -2 yr -1; around half of the acids are removed by dry deposition. It is established that a larger source (˜1.8 times) of both acids is present during the wet season. We speculate that atmospheric oxidation of hydrocarbons should be the main source of HCOOH and CH 3COOH in the Venezuelan atmosphere; soil emissions could make a significant contribution during the dry season.

Sanhueza, Eugenio; Figueroa, Luis; Santana, Magaly

347

Back contact buffer layer for thin-film solar cells  

DOEpatents

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.

Compaan, Alvin D.; Plotnikov, Victor V.

2014-09-09

348

Concentrated Flow through a Riparian Buffer: A Case Study  

NASA Astrophysics Data System (ADS)

Riparian buffers are often used for in-situ treatment of agricultural runoff. Although the benefits of riparian buffers are well recongized, concentration of flow can restrict the efficiency of contaminant removal. This study evaluates flow concentration at a agricultural site near Manhattan, Kansas. Manual and automated GIS analyses of a high-resolution digital elevation model were used to determine the fraction of runoff contributing to each buffer segment. Subsequent simulation of the system in WEPP (Water Erosion and Prediction Project) demonstrates the extend to which flow concentration affects buffer efficiency.

Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

2004-05-01

349

An assessment of buffer strips for improving damage tolerance  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

350

Acetic acid treatment for wrinkle-free oral mucosal epithelia in paraffin section preparation.  

PubMed

For histopathological assessment of oral borderline malignancies, it is important to carefully detect subtle epithelial changes on fully stretched tissue sections. However, it is not generally easy to obtain wrinkle-free sections when using formalin-fixed paraffin-embedded oral mucosal samples. Since acetic acid treatment is already utilized for large brain tissue sections, we examined whether that treatment was also effective for oral mucosal tissues containing normal to malignant epithelial lesions. Paraffin sections were floated in various concentrations of acetic acid for 10 min after stretching in water for 1 min, then wrinkle formations were examined using hematoxylin and eosin staining, as well as for staining intensity with keratin immunohistochemistry. Wrinkles were formed in both epithelial and connective tissue zones of sections treated with less than a 40-mM (0.25%) concentration of acetic acid. In contrast, treatments with concentrations at 80 mM (0.5%) and higher resulted in cracking between the epithelial layer and lamina propria, as well as poor immunohistochemical results for keratins 13 and 17, even though the wrinkles completely disappeared. These results indicate that 40 mM is the optimal concentration of acetic acid solution to prevent wrinkles in the epithelial layer while maintaining the immunohistochemical qualities of oral mucosa tissue sections, especially those containing borderline malignant epithelial lesions. PMID:20623754

Ahsan, Md Shahidul; Maruyama, Satoshi; Cheng, Jun; Al-Eryani, Kamal; Yamazaki, Manabu; Hasegawa, Mayumi; Tsuneki, Masayuki; Saku, Takashi

2011-03-01

351

Characterization of kaolinite-ammonium acetate complexes prepared by one-step homogenization method.  

PubMed

Although kaolinite-ammonium acetate complexes are of interest in the area of kaolinite nanocomposites, the structures of these complexes have remained largely elusive. Experimental and molecular simulation analysis is used to investigate their structures, revealing that two types of water-containing kaolinite-ammonium acetate complex exist. A cost-efficient one-step homogenization method was used to synthesize these complexes. The effect of the aging time and the amount of reagents on the intercalation were characterized experimentally by X-ray diffraction, thermogravimetry, Fourier transform infrared spectroscopy and scanning electron microscopy. The optimal degree of intercalation was obtained by using two orders of magnitude lower amount of reagents than in the case of the solution method. It was found that the so far less investigated 1.7-nm complex has higher water content than the 1.4-nm one. For both complexes, our molecular simulations predict the double-layered structure of the acetate ions, which is usually assumed in the case of the kaolinite-acetate complexes. For the 1.7-nm complex, however, a quasi-triple-layered structure of water molecules instead of the double-layered one was calculated. PMID:24996021

Makó, Éva; Kovács, András; Ható, Zoltán; Zsirka, Balázs; Kristóf, Tamás

2014-10-01

352

Acetate-fed aerobic granular sludge for the degradation of 4-chlorophenol.  

PubMed

Chlorinated phenols are considered a critical environmental problem, due to their extreme toxicity and their widespread use both in industrial and agricultural activities. In this study, aerobic granular sludge was initially developed into an acetate-fed Granulated Sequencing Batch Reactor (GSBR) and then used for the degradation of low chlorinated 4-mono-chlorophenol (4CP), with readily biodegradable sodium acetate (NaAc) as co-substrate. Influent 4CP concentration ranged between 0 and 50mg/l, with a maximum volumetric organic loading rate of 0.20 kg(4CP)/m(3)d (0.32 kg(COD-4CP)/m(3)d). Differences in granules shape and size were observed with 4CP dosed in the influent at different concentrations, and the effects of such toxic compound on acetate removal were evaluated, with both unacclimated and acclimated biomass. Aerobic granules grown on acetate as carbon source proved to be an interesting solution for the degradation of 4CP, showing good resistance to high 4CP concentrations in the influent even if unacclimated (short term effects). Moreover, the monitoring of intermediate products and the evaluation of chloride release due to 4CP degradation proved that acclimated granular sludge could completely remove 4CP (long term effects), with high specific removal rates. PMID:19111986

Carucci, Alessandra; Milia, Stefano; De Gioannis, Giorgia; Piredda, Martina

2009-07-15

353

Acetate-fed aerobic granular sludge for the degradation of chlorinated phenols.  

PubMed

In this study, the possibility to use acetate-fed aerobic granular sludge for the degradation of low chlorinated 4-mono-chlorophenol (4CP) and highly chlorinated 2,4,6-tri- chlorophenol (TCP) was investigated. A Granulated Sequencing Batch Reactor (GSBR) was used to carry out the experiments, with acetate as growth substrate. 4CP concentration in the influent ranged between 0 and 50 mg/l, while TCP concentration varied between 0 and 15 mg/l. Different operating conditions were applied in order to obtain the complete aerobic degradation of 4CP. For TCP degradation, anaerobic feeding and control of dissolved oxygen concentration in the bulk liquid were used to keep the granules core under anaerobic conditions due to diffusion limitations: the possibility to obtain TCP reductive dechlorination under aerated conditions was thus investigated. Differences in granules shape and size were observed with 4CP and TCP dosed in the influent, and the effects of such toxic compounds on acetate removal were evaluated.Aerobic granules grown on acetate as carbon source proved to be an interesting solution for the degradation of 4CP, showing good resistance to high 4CP concentrations in the influent even if unacclimated. The presence of TCP did not irreversibly inhibit biomass activity, and complete TCP degradation was achieved after acclimation. PMID:18701779

Carucci, A; Milia, S; De Gioannis, G; Piredda, M

2008-01-01

354

A novel description of ISFET sensitivity with the buffer capacity and double-layer capacitance as key parameters  

Microsoft Academic Search

The pH sensitivity of ISFETs arises from interactions of protons with ISFET gate surface sites. This sensitivity is described by a new simpler model with the intrinsic buffer capacity and the differential capacitance as key parameters. The obtained expression is independent of the models used for the chemical surface equilibria and the charge profile in the solution. The general expression

R. E. G. van Hal; J. C. T. Eijkel; P. Bergveld

1995-01-01

355

Optimal PHP control of multiple part-types on a failure-prone machine with quadratic buffer costs  

Microsoft Academic Search

We consider a single, failure-prone machine, producing multiple part-types. The goal is to minimize the expected sum of quadratic buffer costs. In general, the optimal solution to this problem is unknown. However, by restricting the allowable set of control policies to the class of prioritized hedging point policies, we are able to determine simple, analytical expressions for the optimal hedging

Chang Shu; James R. Perkins

1998-01-01

356

Optimal PHP production of multiple part-types on a failure-prone machine with quadratic buffer costs  

Microsoft Academic Search

We consider a single, failure-prone machine, producing multiple part-types The objective is to minimize the expected sum of quadratic buffer costs. In general, the optimal solution to this problem is unknown. However, by restricting the allowable set of control policies to the class of prioritized hedging point (PHP) policies, we are able to determine simple, analytical expressions for the optimal

Chang Shu; James R. Perkins

2001-01-01

357

Enhancing soluble phosphorus removal within buffer strips using industrial by-products.  

PubMed

Using industrial by-products (IBPs) in conjunction with buffer strips provides a potentially new strategy for enhancing soluble phosphorus (P) removal from agricultural runoff. Here, we investigate the feasibility of this approach by assessing the P sorption properties of IBPs at different solution-IBPs contact time (1-120 min) and solution pH (3, 5.5, 7.5), as well as possible adverse environmental effects including P desorption or heavy metal mobilisation from IBPs. Batch experiments were carried out on two widely available IBPs in the UK that demonstrated high P sorption capacity but different physicochemical characteristics, specifically ochre and Aluminium (Al) based water treatment residuals (Al-WTR). A series of kinetic sorption-desorption experiments alongside kinetic modelling were used to understand the rate and the mechanisms of P removal across a range of reaction times. The results of the kinetic experiments indicated that P was initially sorbed rapidly to both ochre and Al-WTR, followed by a second phase characterised by a slower sorption rate. The excellent fits of kinetic sorption data to a pseudo-second order model for both materials suggested surface chemisorption as the rate-controlling mechanism. Neither ochre nor Al-WTR released substantial quantities of either P or heavy metals into solution, suggesting that they could be applied to buffer strip soils at recommended rates (?30 g kg(-1) soil) without adverse environmental impact. Although the rate of P sorption by freshly-generated Al-WTR applied to buffer strips reduced following air-drying, this would not limit its practical application to buffer strips in the field if adequate contact time with runoff was provided. PMID:24928382

Habibiandehkordi, Reza; Quinton, John N; Surridge, Ben W J

2014-11-01

358

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

NASA Astrophysics Data System (ADS)

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

Bacinski, John

2013-10-01

359

Effects of Acetate-Free Citrate Dialysate on Glycoxidation and Lipid Peroxidation Products in Hemodialysis Patients  

PubMed Central

Background/Aims Previous studies have shown the presence of high levels of glycoxidation and lipid peroxidation products in association with atherosclerosis in patients with end-stage kidney disease. Acetates are commonly used buffer for correcting metabolic acidosis in hemodialysis (HD) patients. Since the toxic effects of acetates are well established, acetate-free citrate dialysate (AFD) has become available in Japan. The objective of the present study was to evaluate the suppressive effects of AFD on oxidative stress in maintenance HD patients by measuring plasma pentosidine and malondialdehyde-modified low-density lipoprotein (MDA-LDL) levels as markers for glycoxidation and lipid peroxidation products. Methods Plasma pentosidine, MDA-LDL and other laboratory parameters were examined on maintenance HD at the Juntendo University Hospital before and after switching to AFD. Results MDA-LDL levels divided by LDL cholesterol were significantly lower than those before switching to AFD. Furthermore, levels of plasma pentosidine were lower than those before switching to AFD. Stepwise multiple regression analysis revealed that the percent change of the calcium-phosphorus product in the nondiabetic group and that of phosphorus in the diabetic group were predictive variables for the percent change of MDA-LDL/LDL, whereas the percent change of log high-sensitive C-reactive protein and that of systolic blood pressure in the nondiabetic group and that of diastolic blood pressure in the diabetic group were predictive variables for the percent change of plasma pentosidine. Conclusions It appears that AFD decreases glycoxidation and lipid peroxidation products when compared with acid citrate dextrose in HD patients. The reduction of oxidative stress by AFD during HD may have possible beneficial effects on atherosclerosis through calcium-phosphorus metabolism and blood pressure. PMID:23599704

Masuda, Atsumi; Hagiwara, Shinji; Tanimoto, Mitsuo; Kodama, Fumiko; Okumura, Kozue; Nohara, Nao; Matsumoto, Mayumi; Maiguma, Masayuki; Omote, Keisuke; Io, Hiroaki; Kurusu, Atsushi; Ohsawa, Isao; Shimizu, Yoshio; Hamada, Chieko; Horikoshi, Satoshi; Tomino, Yasuhiko

2012-01-01

360

Crystal structure and chemical bonding in tin(II) acetate  

Microsoft Academic Search

Tin(II) acetate was prepared and its crystal structure was solved from X-ray powder diffraction data. Tin(II) acetate adopts a polymeric structure consisting of infinite Sn(CH3COO)2 chains running along the c-axis which are packed into groups of four. The acetate groups bridge the Sn atoms along the chains. The Sn atoms are asymmetrically surrounded by four oxygen atoms with two short

Varvara S. Stafeeva; Alexander S. Mitiaev; Artem M. Abakumov; Alexander A. Tsirlin; Artem M. Makarevich; Evgeny V. Antipov

2007-01-01

361

The acetate kinase of Clostridum acetobutylicum strain P262  

Microsoft Academic Search

Clostridum acetobutylicum strain P262 fermented glucose, pyruvate, or lactate, and the butyrate production was substrate-dependent. Differences in butyrate yield could not be explained by changes in butyrate kinase activities, but the butyrate production was inversely related to acetate kinase activity. The acetate kinase had a pH optimum of 8.0, aKm for acetate of 160 mM, and akcat of 16,800 min-1.

Francisco Diez-Gonzalez; James B. Russell; Jean B. Hunter

1996-01-01

362

Mesophilic syntrophic acetate oxidation during methane formation in biogas reactors  

Microsoft Academic Search

The reaction pathway for the formation of methane from acetate was investigated in sludge from 13 different biogas reactors. By following the conversion of [2-14C]acetate and [14C]bicarbonate it was shown that methane formation by syntrophic acetate oxidation was the dominating mechanism for acetotrophic methanogenesis in sludge containing high levels of salts, mainly ammonium, and volatile fatty acids. In one biogas

Anna Schnürer; Gerhard Zellner; Bo H. Svensson

1999-01-01

363

Studies on the growth aspects of semi-organic cadmium zinc thiourea acetate: A promising new NLO crystal  

Microsoft Academic Search

Single crystals of a new nonlinear optical material, cadmium zinc thiourea acetate (CZTA), were successfully grown by slow evaporation of the aqueous solution at room temperature. Single crystal X-ray diffraction pattern and FTIR spectrum analysis have confirmed the formation of the new crystal. The optical transmission studies and second harmonic generation (SHG) efficiency studies justified the device quality of the

K. Kirubavathi; K. Selvaraju; R. Valluvan; N. Vijayan; S. Kumararaman

2008-01-01

364

Developing Suitable Buffers to Capture Transport Cycling Behavior  

PubMed Central

The association between neighborhood built environment and cycling has received considerable attention in health literature over the last two decades, but different neighborhood definitions have been used and it is unclear which one is most appropriate. Administrative or fixed residential spatial units (e.g., home-buffer-based neighborhoods) are not necessarily representative for environmental exposure. An increased understanding of appropriate neighborhoods is needed. GPS cycling tracks from 78 participants for 7?days form the basis for the development and testing of different neighborhood buffers for transport cycling. The percentage of GPS points per square meter was used as indicator of the effectiveness of a series of different buffer types, including home-based network buffers, shortest route to city center buffers, and city center-directed ellipse-shaped buffers. The results show that GPS tracks can help us understand where people go and stay during the day, which can help us link built environment with cycling. Analysis showed that the further people live from the city center, the more elongated are their GPS tracks, and the better an ellipse-shaped directional buffer captured transport cycling behavior. In conclusion, we argue that in order to be able to link built environment factors with different forms of physical activity, we must study the most likely area people use. In this particular study, to capture transport cycling, with its relatively large radius of action, city center-directed ellipse-shaped buffers yielded better results than traditional home-based network buffer types. The ellipse-shaped buffer types could therefore be considered an alternative to more traditional buffers or administrative units in future studies of transport cycling behavior. PMID:24926478

Madsen, Thomas; Schipperijn, Jasper; Christiansen, Lars Breum; Nielsen, Thomas Sick; Troelsen, Jens

2014-01-01

365

Cellulose acetate hollow fiber ultrafiltration membranes made from CA\\/PVP 360 K\\/NMP\\/water  

Microsoft Academic Search

Hydrophilic hollow fiber ultrafiltration (UF) membranes have been prepared from a new dope solution containing cellulose acetate (CA)\\/poly(vinyl pyrrolidone) (PVP 360K)\\/N-methyl-2-pyrrolidone (NMP)\\/water with a mass ratio of 19.0\\/5.0\\/74.8\\/1.2 by using a dry-jet wet spinning process. The effect of air-gap length was studied. The as-spun fibers were post-treated by means of a hypochlorite solution of 200mgl?1 (200ppm) over different duration. The

Jian-Jun Qin; Ying Li; Leng-Siang Lee; Hsiaowan Lee

2003-01-01

366

Polypyrrole based strong acid catalyst for acetalization  

NASA Astrophysics Data System (ADS)

Novel polypyrrole based acid catalyst has been synthesized through the neutralization reaction of polypyrrole and sulfuric acid. The polypyrrole based acid owned the acidity as high as 6.0 mmol/g, which was much higher than that of the traditional solid acids such as Nafion and Amberlyst-15 (0.8 mmol/g). The catalytic activities of the novel solid acid were investigated through the acetalization. The results showed that the novel solid acid held high activities for the reactions. Furthermore, the recycled activities of the catalyst indicated that the solid acid owned high stability during the catalytic process and little acid sites dropped from polypyrrole. The high acidity and stability made the novel polypyrrole based acid hold great potential for the green chemical processes.

Liang, Xuezheng; Cheng, Yuxiao; Qi, Chenze

2011-09-01

367

N-(2-Chloro-acet-yl)glycine.  

PubMed

The title compound, C4H6ClNO3, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In each mol-ecule, there are N-H?O and N-H?Cl hydrogen bonds. Both mol-ecules are relatively planar, with the mean plane of the acetamide [N-C(=O)C] group being inclined to the mean plane of the acetate group [C-C(=O)O] by 9.23?(13)° in mol-ecule A and 6.23?(12)° in mol-ecule B. In the crystal, adjacent mol-ecules are linked by O-H?O hydrogen bonds and weak C-H?O contacts forming -A-A-A- and -B-B-B- parallel chains propagating along the a-axis direction. PMID:24454136

Zhang, Yu-Cheng; Zhang, Xiu-Qin; Wang, Kai; Chen, Qiang

2013-10-26

368

This paper presents LEOPARD, a Logical Effort-based fanout OPtimizer for ARea and Delay, which relies on the availability of a (near) continuous size buffer library. Based on the concept of  

E-print Network

the required time and input capacitance constraints by constructing the fanout tree topol- ogy and assigning the buffer sizes. More precisely, the proposed algorithm produces the optimum fanout tree solution if the fanout tree topology is restricted to a chain of buffers. For the case that a discrete size library

Pedram, Massoud

369

Photoluminescence of cellulose acetate and silica sphere composite  

NASA Astrophysics Data System (ADS)

Strong blue and green light emission has been observed from the cellulose acetate (CA) and silica sphere composite. Two different amounts of silica spheres were mixed in the CA solution to fabricate large area super-hydrophobic films. The silica spheres and CA solution ratios were 0.07:4.0 (SSCA-A) and 0.14:4.0 (SSCA-B). The milky color solution of SSCA-A and SSCA-B slowly turned to light yellow and red, respectively, with the time passed. The colors became intense yellow and red for the SSCA-A and SSCA-B, respectively, after 38 days. FTIR spectra show more absorption at 3478 cm-1 corresponding sbnd OH stretching vibration, at 2963 cm-1 caused by sbnd CH stretching vibration, at 1746 and 1713 cm-1 representing the Cdbnd O stretching vibration, and at 1100 cm-1 corresponding sbnd Rsbnd OH and Sisbnd Osbnd Si stretching vibration for CA and silica. Therefore, aged SSCA-A and SSCA-B have more sbnd OH, sbnd CH, sbnd Cdbnd O, and Sisbnd Osbnd Si groups than pure CA. UV-visible spectra show the absorption peaks at 410 nm for both SSCA-A and SSCA-B. Photoluminescence (PL) peaks were shifted toward longer wavelength with the increase of the excitation wavelength and became maximum at approximately 470 nm with excitation wavelength at 400 nm for the SSCA-A. There were two maximum luminescence peaks at 470 and 530 nm with the excitation wavelength at 400 and 470 nm, respectively, for the SSCA-B. The luminescence peak shift was due to the multiple emission center proved by the different excitation energy.

Kang, Kwang-Sun

2014-08-01

370

High performance polymer solar cells with as-prepared zirconium acetylacetonate film as cathode buffer layer  

PubMed Central

Low-work-function active metals are commonly used as cathode in polymer solar cells (PSCs), but sensitivity of the active metals towards moisture and oxygen results in poor stability of the devices. Therefore, solution-proceessable and stable cathode buffer layer is of great importance for the application of PSCs. Here we demonstrate high performance PSCs by employing as-prepared zirconium acetylacetonate (a-ZrAcac) film spin-cast from its ethanol solution as cathode buffer layer. The PSCs based on a low bandgap polymer PBDTBDD as donor and PC60BM as acceptor with a-ZrAcac/Al cathode demonstrated an average power conversion efficiency (PCE) of 8.75% which is significantly improved than that of the devices with traditional Ca/Al cathode. The improved photovoltaic performance is benefitted from the decreased series resistance and enhanced light harvest of the PSCs with the a-ZrAcac/Al cathode. The results indicate that a-ZrAcac is a promising high performance cathode buffer layer for fabricating large area flexible PSCs. PMID:24732976

Tan, Zhan'ao; Li, Shusheng; Wang, Fuzhi; Qian, Deping; Lin, Jun; Hou, Jianhui; Li, Yongfang

2014-01-01

371

Current isolating epitaxial buffer layers for high voltage photodiode array  

DOEpatents

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.

Morse, Jeffrey D. (Martinez, CA); Cooper, Gregory A. (Pleasant Hill, CA)

2002-01-01

372

Variable optical buffer using slow light in semiconductor nanostructures  

Microsoft Academic Search

A compact variable all-optical buffer using semiconductor quantum dot (QD) structures is proposed and analyzed. The buffering effect is achieved by slowing down the optical signal using an external control light source to vary the dispersion characteristic of the medium via an electromagnetically induced transparency effect. We present a theoretical investigation of the criteria for achieving slow light in semiconductor

CONNIE J. CHANG-HASNAIN; Pei-cheng Ku; Jungho Kim; Shun-lien Chuang

2003-01-01

373

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...

374

Metal nanostructure growth on molecular buffer layers of CO2  

E-print Network

- ter nucleation, and the desorption of the buffer activated cluster diffusion and aggregation dependence that agreed well with simulations of diffusion-limited cluster­cluster aggregation [6]. The physics of clus- ter diffusion on an incommensurate rare gas buffer was investigated by Antonov et al. [7

Weaver, John H.

375

The GCX System: Dynamic Buffer Minimization in Streaming XQuery Evaluation  

Microsoft Academic Search

In this demonstration, we present the main-memory based stream- ing XQuery engine GCX which implements novel buffer manage- ment strategies that combine static and dynamic analysis to keep main memory consumption low. Depending on the progress made in query evaluation, memory buffers are dynamically purged and minimized. In this demo, we show the various stages in evaluat- ing a practical

Christoph Koch; Stefanie Scherzinger; Michael Schmidt

2007-01-01

376

PLACEMENT OF RIPARIAN FOREST BUFFERS TO IMPROVE WATER QUALITY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Riparian forest buffers can improve stream water quality, provided they intercept and remove contaminants from surface runoff and/or shallow groundwater. Soils, topography, hydrology, and surficial geology determine the capability of forest buffers to intercept and treat these flows. This paper desc...

377

Cable Modem Buffer Management in DOCSIS Jim Martin,  

E-print Network

Cable Modem Buffer Management in DOCSIS Networks Jim Martin, James Westall School of Computing queue located in the cable modem. The strategy must contend with conflicting goals: large buffers might) amount of data. However, the upstream data rate available to a cable modem varies with the number

Martin, Jim

378

STABILITY CONDITIONS FOR SOME DISTRIBUTED SYSTEMS: BUFFERED RANDOM ACCESS SYSTEMS  

E-print Network

STABILITY CONDITIONS FOR SOME DISTRIBUTED SYSTEMS: BUFFERED RANDOM ACCESS SYSTEMS August 18, 1993.S.A. Abstract We consider the standard slotted ALOHA system with a finite number of buffered users. Stability on the stability region have been established, however, the exact stability region is known only for the symmetric

Szpankowski, Wojciech

379

Methods for improved growth of group III nitride buffer layers  

DOEpatents

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).

Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

2014-07-15

380

Design and Performance Analysis of Buffers: A Constructive Approach  

Microsoft Academic Search

This paper presents a theoretical framework to analyse the correctness of VLSI programs for buffers and to compare the performance of the corresponding circuits. A very simple calculus consisting of only two operators is presented that suffices to establish the functional correctness of complicated buffer designs. Furthermore, sequence functions are presented both as a formalism to show absence of deadlock

Rudolf H. Mak

2002-01-01

381

A buffer storage resource allocation model for cellular manufacturing systems  

Microsoft Academic Search

Among other functions, buffer storage facilitates the decoupling of production and materials handling in a manufacturing system. This can yield higher utilization of materials handling resources and reduced disruptions to production operations associated with response times for materials handling transactions. However, buffer storage requires the allocation of capital resources for space, fixtures, and equipment. If it is not practical to

Charles J. Malmborg

1995-01-01

382

Adaptive Backpressure: Efficient Buffer Management for On-Chip Networks  

E-print Network

Adaptive Backpressure: Efficient Buffer Management for On-Chip Networks Daniel U. Becker, Nan Jiang Backpressure, a novel scheme that improves the utilization of dynamically man- aged router input buffers mesh network show that Adaptive Backpressure improves network stability, leading to an average 2

383

CS 429H, Spring 2014 Lab 5: The Buffer Bomb  

E-print Network

CS 429H, Spring 2014 Lab 5: The Buffer Bomb Assigned: March 6, 2014, Due: March 20, 2014 convention it wants, so long as it's consistent. Hand Out Instructions You can obtain your buffer bomb bomb program you will attack. makecookie: Generates a "cookie" based on your userid. hex2raw: A utility

Witchel, Emmett

384

Efficient Buffer Design Algorithms for Production Line Profit Maximization  

E-print Network

Efficient Buffer Design Algorithms for Production Line Profit Maximization by Chuan Shi B;6 #12;Efficient Buffer Design Algorithms for Production Line Profit Maximization by Chuan Shi Submitted contributions to production system profit maximization. The profit of a production line is the revenue

Gershwin, Stanley B.

385

Modular checking for buffer overflows in the large  

Microsoft Academic Search

We describe an ongoing project, the deployment of a modu- lar checker to statically find and prevent every buffer over- flow in future versions of a Microsoft product. Lightweight annotations specify requirements for safely using each buffer, and functions are checked individually to ensure they obey these requirements and do not overflow. To date over 400,000 annotations have been added

Brian Hackett; Manuvir Das; Daniel Wang; Zhe Yang

2006-01-01

386

Buffer Layer Assisted Laser Patterning of Metals on Surfaces  

E-print Network

Buffer Layer Assisted Laser Patterning of Metals on Surfaces Gabriel Kerner and Micha Asscher has been patterned on a Ru(100) substrate under UHV conditions. Upon annealing, the physisorbed layer controlled metallic clusters via buffer layer assisted growth (BLAG).9-11 To create clusters, the metal

Asscher, Micha

387

Delineation of Preventative Landslide Buffers Along Steep Streamside Slopes in  

E-print Network

213 Delineation of Preventative Landslide Buffers Along Steep Streamside Slopes in Northern of sediment delivering to watercourses as a result of landslides generated by forest management related operations. Initial default buffers were developed through a landslide study during the planning stages

Standiford, Richard B.

388

Function, Design, and Establishment of Riparian Forest Buffers: A Review  

Microsoft Academic Search

protect and improve water quality, provide habitat for plants and animals, support aquatic communities, and provide many benefits to humans. Virginia, along with other states in the Chesapeake Bay region, has recognized the importance of riparian forests by implementing a plan to restore forested buffers along streams, rivers, and lakes. This project reviews selected literature on riparian forest buffers, including

Julia Caldwell Klapproth; James E. Johnson

389

Optimal Buffer Size for Wireless Mesh Networks! INTRODUCTION!  

E-print Network

, and the kernel transmit queue (txqueue) is altered as per our proposed framework.! PERFORMANCE ANALYSIS.! PERFORMANCE ANALYSIS - TESTBED! Distributed neighborhood buffer is validated on a 10-node WMN testbed 0 through 5 b1 :b2 ::bM =1: 2 :: M B RTT · 50 packets buffer CDF Delay (ms

Chaudhuri, Surajit

390

Buffer standards for the physiological pH of N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES) from (278.15 to 328.15) K  

PubMed Central

This paper reports the results for the pH of six buffer solutions free of chloride ion with compositions: (a) BES (0.03 mol·kg?1) + NaBES (0.09 mol·kg?1); (b) BES (0.02 mol·kg?1) + NaBES (0.04 mol·kg?1); (c) BES (0.04 mol·kg?1) + NaBES (0.08 mol·kg?1); (d) BES (0.04 mol·kg?1) + NaBES (0.04 mol·kg?1) (e) BES (0.05 mol·kg?1) + NaBES (0.05 mol·kg?1); and (f) (0.06 mol·kg?1) + NaBES (0.06 mol·kg?1). The remaining eight buffer solutions (g) to (n) have saline media of the ionic strength I = 0.16 mol·kg?1, matching closely to that of the physiological sample. Conventional paH values, designated as pH(s), for all six buffer solutions (a) – (f) without the chloride ion and eight buffer solutions with the chloride ion (g) – (n) at I = 0.16 mol·kg?1 from (278.15 K to 328.15) K have been calculated. The operational pH values for five buffer solutions at T = 298.15 K and T = 310.15 K have been determined based on the difference in the values of the liquid junction potentials between the blood phosphate standard and the experimental buffer solutions. Five of these buffers are recommended as secondary standards for the physiological pH range 7.5 to 8.5. PMID:22247703

Roy, Rabindra N.; Roy, Lakshmi N.; Stegner, Jessica M.; Sechler, Shay A.; Jenkins, Alexis L.; Krishchenko, Roman; Henson, Isaac B.

2011-01-01

391

Amelogenin-enamelin association in phosphate-buffered saline.  

PubMed

The structures and interactions among macromolecules in the enamel extracellular matrix play vital roles in regulating hydroxyapatite crystal nucleation, growth, and maturation. We used dynamic light scattering (DLS), circular dichroism (CD), fluorescence spectroscopy, and transmission electron microscopy (TEM) to investigate the association of amelogenin and the 32-kDa enamelin, at physiological pH 7.4, in phosphate-buffered saline (PBS). The self-assembly behavior of amelogenin (rP148) was altered following addition of the 32-kDa enamelin. Dynamic light scattering revealed a trend for a decrease in aggregate size in the solution following the addition of enamelin to amelogenin. A blue-shift and intensity increase of the ellipticity minima of rP148 in the CD spectra upon the addition of the 32-kDa enamelin, suggest a direct interaction between the two proteins. In the fluorescence spectra, the maximum emission of rP148 was red-shifted from 335 to 341 nm with a marked intensity increase in the presence of enamelin as a result of complexation of the two proteins. In agreement with DLS data, TEM imaging showed that the 32-kDa enamelin dispersed the amelogenin aggregates into oligomeric particles and stabilized them. Our study provides novel insights into understanding the possible cooperation between enamelin and amelogenin in macromolecular co-assembly and in controlling enamel mineral formation. PMID:22243267

Yang, Xiudong; Fan, Daming; Mattew, Shibi; Moradian-Oldak, Janet

2011-12-01

392

A reappraisal of the reaction of butyrylcoenzyme A dehydrogenase with phenylmercuric acetate. Evidence that de-greening involves a reaction of the tightly bound thioester  

PubMed Central

Phenylmercuric acetate reversibly de-greens butyryl-CoA dehydrogenase from Megasphaera elsdenii, abolishing the absorption band at 710nm. The view that this is a result of modification of a protein thiol group is re-examined in the light of the following new observations. (i) After treatment with phenylmercuric acetate, the enzyme's ability to be re-greened by addition of thiols was not decreased by gel filtration or precipitation with (NH4)2SO4. (ii) Phenylmercuric acetate caused the same extent of de-greening whether added in a few large amounts or many small ones. The overall time taken for de-greening was, however, greatly extended when many small additions were made. (iii) In Tris/acetate buffer, pH7.5, 3.5mol of phenylmercuric acetate/mol of enzyme subunit was required for complete de-greening, compared with only 2.5mol/mol in phosphate buffer, pH7. (iv) None of the groups that react with phenylmercuric acetate is accessible to iodoacetate or iodoacetamide. (v) On a molar basis dithiothreitol, mercaptoethanol and CoA are equally effective in re-greening the enzyme. (vi) Provided that phenylmercuric acetate is not present in excess, the de-greened enzyme forms normal and stable complexes with crotonyl-CoA and acetoacetyl-CoA. (vii) When a small excess of phenylmercuric acetate is present, full stable development of the enzyme–acetoacetyl-CoA complex requires addition of several mol of acetoacetyl-CoA/mol of enzyme subunit. (viii) The ability of de-greened enzyme to be immediately re-greened by an excess of thiol declines with time, more rapidly at pH6 than at pH7 or 8, but at all three pH values the instantaneous re-greening was followed by a slow phase of further increase in A710. This further recovery was most extensive and most rapid at pH8. These findings are reminiscent of the previously described reversible decline in the re-greening capacity of a protein-free acid extract of green butyryl-CoA dehydrogenase. It is concluded that the likely cause of de-greening is chemical modification of the tightly bound thioester rather than a protein thiol group. The reversibility would be explained if the thioester exists on the surface of the enzyme in equilibrium with free CoA and a lactone, or if the acyl group is readily and reversibly transferred from the thiol of CoA to a protein side chain. PMID:25661

Engel, Paul C.; Jones, Janet B.

1978-01-01

393

Oxidation of Indole-3-Acetic Acid to Oxindole-3-Acetic Acid by an Enzyme Preparation from Zea mays1  

PubMed Central

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants. PMID:11538238

Reinecke, Dennis M.; Bandurski, Robert S.

1988-01-01

394

Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays  

NASA Technical Reports Server (NTRS)

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

Reinecke, D. M.; Bandurski, R. S.

1988-01-01

395

Replenishing data descriptors in a DMA injection FIFO buffer  

DOEpatents

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.

Archer, Charles J. (Rochester, MN); Blocksome, Michael A. (Rochester, MN); Cernohous, Bob R. (Rochester, MN); Heidelberger, Philip (Cortlandt Manor, NY); Kumar, Sameer (White Plains, NY); Parker, Jeffrey J. (Rochester, MN)

2011-10-11

396

A wide bandwidth CCD buffer memory system  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

397

Ultracompact optical buffers on a silicon chip  

NASA Astrophysics Data System (ADS)

On-chip optical buffers based on waveguide delay lines might have significant implications for the development of optical interconnects in computer systems. Silicon-on-insulator (SOI) submicrometre photonic wire waveguides are used, because they can provide strong light confinement at the diffraction limit, allowing dramatic scaling of device size. Here we report on-chip optical delay lines based on such waveguides that consist of up to 100 microring resonators cascaded in either coupled-resonator or all-pass filter (APF) configurations. On-chip group delays exceeding 500 ps are demonstrated in a device with a footprint below 0.09 mm2. The trade-offs between resonantly enhanced group delay, device size, insertion loss and operational bandwidth are analysed for various delay-line designs. A large fractional group delay exceeding 10 bits is achieved for bit rates as high as 20 Gbps. Measurements of system-level metrics as bit error rates for different bit rates demonstrate error-free operation up to 5 Gbps.

Xia, Fengnian; Sekaric, Lidija; Vlasov, Yurii

2007-01-01

398

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOEpatents

This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

Ramprasad, D.; Waller, F.J.

1999-04-06

399

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOEpatents

This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

Ramprasad, Dorai (Allentown, PA); Waller, Francis Joseph (Allentown, PA)

1999-01-01

400

Permeation study of five formulations of alpha-tocopherol acetate through human cadaver skin.  

PubMed

Alpha-tocopherol (AT) is the vitamin E homologue with the highest in vivo biological activity. AT protects against the carcinogenic and mutagenic activity of ionizing radiation and chemical agents, and possibly against UV-induced cutaneous damage. For stability consideration, alpha-tocopherol is usually used as its prodrug ester, alpha-tocopherol acetate (ATA), which once absorbed into the skin is hydrolyzed to alpha-tocopherol, the active form. The objective of this research was to characterize in vitro the permeation properties of ATA from various solutions and gel formulations. Permeation studies were conducted using modified Franz diffusion cells and human cadaver skin as the membrane. Specifically, 5% (w/w) alpha-tocopherol acetate was formulated in the following vehicles: ethanol, isopropyl myristate, light mineral oil, 1% Klucel gel in ethanol, and 3% Klucel gel in ethanol (w/w). The receiver temperature was 37 degrees C. Samples from the receiver were collected at 2, 4, 6, 8, 12, 24, 30, 36, and 48 hours and analyzed by HPLC for concentrations of alpha-tocopherol acetate and alpha-tocopherol. The permeabilities of ATA through human cadaver skin were 1.0x10(-4), 1.1x10(-2), 1.4x10(-4), 2.1x10(-4), and 4.7x10(-4) cm/h for the ethanol solution, isopropyl myristate solution, light mineral oil solution, 1% Klucel gel, and 3% Klucel gel, respectively. The results show that the formulation had relatively minor effects on the permeability coefficients of ATA through cadaver skin in all cases except for the isopropyl myristate solution. PMID:15868062

Mahamongkol, Hansa; Bellantone, Robert A; Stagni, Grazia; Plakogiannis, Fotios M

2005-01-01

401

The effects of buffer structure in buffer-layer-assisted growth: Grain boundaries, grooves, and pattern transfer  

E-print Network

gas thin solid films have been used to create a wide range of nanostructures through buffer of Au atoms onto these surfaces produces clusters, and warm-up induces clus- ter diffusion and aggregation during buffer desorption before delivery to the surface. Transmission electron microscopy results

Weaver, John H.

402

The effects of buffer structure in buffer-layer-assisted growth: Grain boundaries, grooves, and pattern transfer  

Microsoft Academic Search

Rare gas thin solid films have been used to create a wide range of nanostructures through buffer-layer-assisted growth. This paper examines effects related to the microstructure of the buffer layer and demonstrates that those effects can be used to produce nanostructures with different spatial distributions. We show that ?100ML thick Xe films form large columnar grains through secondary grain growth

J. S. Palmer; V. N. Antonov; A. S. Bhatti; P. Swaminathan; P. S. Waggoner; J. H. Weaver

2005-01-01

403

The effects of buffer structure in buffer-layer-assisted growth: Grain boundaries, grooves, and pattern transfer  

Microsoft Academic Search

Rare gas thin solid films have been used to create a wide range of nanostructures through buffer-layer-assisted growth. This paper examines effects related to the microstructure of the buffer layer and demonstrates that those effects can be used to produce nanostructures with different spatial distributions. We show that ˜100 ML thick Xe films form large columnar grains through secondary grain

J. S. Palmer; V. N. Antonov; A. S. Bhatti; P. Swaminathan; P. S. Waggoner; J. H. Weaver

2005-01-01

404

Corrosion in low dielectric constant Si-O based thin films: Buffer concentration effects  

NASA Astrophysics Data System (ADS)

Organosilicate glass (OSG) is often used as an interlayer dielectric (ILD) in high performance integrated circuits. OSG is a brittle material and prone to stress-corrosion cracking reminiscent of that observed in bulk glasses. Of particular concern are chemical-mechanical planarization techniques and wet cleans involving solvents commonly encountered in microelectronics fabrication where the organosilicate film is exposed to aqueous environments. Previous work has focused on the effect of pH, surfactant, and peroxide concentration on the subcritical crack growth of these films. However, little or no attention has focused on the effect of the conjugate acid/base concentration in a buffer. Accordingly, this work examines the "strength" of the buffer solution in both acidic and basic environments. The concentration of the buffer components is varied keeping the ratio of acid/base and therefore pH constant. In addition, the pH was varied by altering the acid/base ratio to ascertain any additional effect of pH. Corrosion tests were conducted with double-cantilever beam fracture mechanics specimens and fracture paths were verified with ATR-FTIR. Shifts in the threshold fracture energy, the lowest energy required for bond rupture in the given environment, GTH, were found to shift to lower values as the concentration of the base in the buffer increased. This effect was found to be much larger than the effect of the hydroxide ion concentration in unbuffered solutions. The results are rationalized in terms of the salient chemical bond breaking process occurring at the crack tip and modeled in terms of the chemical potential of the reactive species.

Zeng, F. W.; Gates, S. M.; Lane, M. W.

2014-05-01

405

Corrosion in low dielectric constant Si-O based thin films: Buffer concentration effects  

SciTech Connect

Organosilicate glass (OSG) is often used as an interlayer dielectric (ILD) in high performance integrated circuits. OSG is a brittle material and prone to stress-corrosion cracking reminiscent of that observed in bulk glasses. Of particular concern are chemical-mechanical planarization techniques and wet cleans involving solvents commonly encountered in microelectronics fabrication where the organosilicate film is exposed to aqueous environments. Previous work has focused on the effect of pH, surfactant, and peroxide concentration on the subcritical crack growth of these films. However, little or no attention has focused on the effect of the conjugate acid/base concentration in a buffer. Accordingly, this work examines the “strength” of the buffer solution in both acidic and basic environments. The concentration of the buffer components is varied keeping the ratio of acid/base and therefore pH constant. In addition, the pH was varied by altering the acid/base ratio to ascertain any additional effect of pH. Corrosion tests were conducted with double-cantilever beam fracture mechanics specimens and fracture paths were verified with ATR-FTIR. Shifts in the threshold fracture energy, the lowest energy required for bond rupture in the given environment, G{sub TH}, were found to shift to lower values as the concentration of the base in the buffer increased. This effect was found to be much larger than the effect of the hydroxide ion concentration in unbuffered solutions. The results are rationalized in terms of the salient chemical bond breaking process occurring at the crack tip and modeled in terms of the chemical potential of the reactive species.

Zeng, F. W.; Lane, M. W., E-mail: mlane@ehc.edu [Department of Chemistry, Emory and Henry College, Emory, Virginia 24340 (United States); Gates, S. M. [IBM TJ Watson Research Center, Yorktown Heights, New York 10598 (United States)] [IBM TJ Watson Research Center, Yorktown Heights, New York 10598 (United States)

2014-05-15

406

PHOTOLYSIS RATES OF (2,4,5-TRICHLOROPHENOXY)ACETIC ACID AND 4-AMINO-3,5,6-TRICHLOROPICOLINIC ACID IN NATURAL WATERS  

EPA Science Inventory

Photoreactions of (2,45-trichlorophenoxy) acetic acid (2,4,5-T) and 4-amino-3,5,6-trichloropicolinic acid (picloram) were studied in distilled water, natural water samples, fulvic acid solutions, and solutions containing iron (III) and/or hydrogen peroxide to determine the effect...

407

Formation of membranes by means of immersion precipitation : Part II. the mechanism of formation of membranes prepared from the system cellulose acetate-acetone-water  

Microsoft Academic Search

Using equations and boundary conditions derived in Part I1, calculations have been performed on the ternary diffusion processes that occur in a cellulose acetate (CA) -acetone casting solution immersed into a water bath. The necessary concentration-dependent thermodynamic and hydrodynamic parameters have been derived from experimental data on the three limiting binary mixtures. Calculations show that immersion of the polymer solution

A. J. Reuvers; C. A. Smolders

1987-01-01

408

Origin and fate of acetate in an acidic fen.  

PubMed

Acetate is a central intermediate in the anaerobic degradation of organic matter, and the resolution of its metabolism necessitates integrated strategies. This study aims to (1) estimate the contribution of acetogenesis to acetate formation in an acidic fen (pH ~ 4.9), (2) assess the genetic potential for acetogenesis targeting the fhs gene encoding formyltetrahydrofolate synthetase (FTHFS) and (3) unravel the in situ turnover of acetate using stable carbon isotope pore-water analysis. H(2)/CO(2)-supplemented peat microcosms yielded (13)C-depleted acetate (-37.2‰ vs. VPDB (Vienna Peedee belemnite standard) compared with -14.2‰ vs. VPDB in an unamended control), indicating the potential for H(2)-dependent acetogenesis. Molecular analysis revealed a high diversity and depth-dependent distribution of fhs phylotypes with the highest number of operational taxonomic units in 0-20 cm depth, but only few and distant relationships to known acetogens. In pore waters, acetate concentrations (0-170 ?M) and ?(13)C-values varied widely (-17.4‰ to -3.4‰ vs. VPDB) and did not indicate acetogenesis, but pointed to a predominance of sinks, which preferentially consumed (12)C-acetate, like acetoclastic methanogenesis. However, depth profiles of methane and ?(13)C(CH4) revealed a temporarily and spatially restricted role of this acetate sink and suggest other processes like sulfate and iron reduction played an important role in acetate turnover. PMID:22404042

Hädrich, Anke; Heuer, Verena B; Herrmann, Martina; Hinrichs, Kai-Uwe; Küsel, Kirsten

2012-08-01

409

Introduction Metal acetates are used as metal precursors in many  

E-print Network

facilitated exploring broader applications of metal and metal oxide nanoparticles by utilizing the synthesis properties of the solid phase metal acetate precursors and the product metal/metal oxide nanocomposite in these combustion and other synthesis systems which rely on thermal decomposition and oxidation of metal acetates [6

Wooldridge, Margaret S.

410

Transition-Metal-Catalyzed Carbonylation of Methyl Acetate.  

ERIC Educational Resources Information Center

Presents a study of the rhodium-catalyzed, ioding-promoted carbonylation of methyl acetate. This study provides an interesting contrast between the carbonylation of methyl acetate and the carbonylation of methanol when similar rhodium/iodine catalyst systems are used. (JN)

Polichnowski, S. W.

1986-01-01

411

Enrichment of amino acid-oxidizing, acetate-reducing bacteria.  

PubMed

In anaerobic condition, amino acids are oxidatively deaminated, and decarboxylated, resulting in the production of volatile fatty acids. In this process, excess electrons are produced and their consumption is necessary for the accomplishment of amino acid degradation. In this study, we anaerobically constructed leucine-degrading enrichment cultures from three different environmental samples (compost, excess sludge, and rice field soil) in order to investigate the diversity of electron-consuming reaction coupled to amino acid oxidation. Constructed enrichment cultures oxidized leucine to isovalerate and their activities were strongly dependent on acetate. Analysis of volatile fatty acids (VFAs) profiles and community structure analysis during batch culture of each enrichment indicated that Clostridium cluster I coupled leucine oxidation to acetate reduction in the enrichment from the compost and the rice field soil. In these cases, acetate was reduced to butyrate. On the other hand, Clostridium cluster XIVb coupled leucine oxidation to acetate reduction in the enrichment from the excess sludge. In this case, acetate was reduced to propionate. To our surprise, the enrichment from rice field soil oxidized leucine even in the absence of acetate and produced butyrate. The enrichment would couple leucine oxidation to reductive butyrate synthesis from CO2. The coupling reaction would be achieved based on trophic link between hydrogenotrophic acetogenic bacteria and acetate-reducing bacteria by sequential reduction of CO2 and acetate. Our study suggests anaerobic degradation of amino acids is achieved yet-to-be described reactions. PMID:24630616

Ato, Makoto; Ishii, Masaharu; Igarashi, Yasuo

2014-08-01

412

Acetic acid pulping of wheat straw under atmospheric pressure  

Microsoft Academic Search

Atmospheric acetic acid pulping of wheat straw was carried out. Pulping conditions and their effects on pulp properties were investigated in detail, and a comparison between acetic acid (AcOH) pulp and soda-anthraquinone (AQ) pulps of wheat straw was made of the chemical com- position, strength, and fiber morphology of the pulps. Wheat straw was successfully pulped and fractionated into pulp

Xue-Jun PanYoshihiro Sano

1999-01-01

413

An on-line potentiometric sequential injection titration process analyser for the determination of acetic acid.  

PubMed

An on-line potentiometric sequential injection titration process analyser for the determination of acetic acid is proposed. A solution of 0.1 mol L(-1) sodium chloride is used as carrier. Titration is achieved by aspirating acetic acid samples between two strong base-zone volumes into a holding coil and by channelling the stack of well-defined zones with flow reversal through a reaction coil to a potentiometric sensor where the peak widths were measured. A linear relationship between peak width and logarithm of the acid concentration was obtained in the range 1-9 g/100 mL. Vinegar samples were analysed without any sample pre-treatment. The method has a relative standard deviation of 0.4% with a sample frequency of 28 samples per hour. The results revealed good agreement between the proposed sequential injection and an automated batch titration method. PMID:12207255

van Staden, J F; Mashamba, Mulalo G; Stefan, Raluca I

2002-09-01

414

Delay analysis of an input buffered ATM switch under two different scheduling disciplines  

Microsoft Academic Search

Depending on the buffer arrangement, space division ATM switch architectures are classified into three main categories: input buffered, output buffered and centrally buffered switches. Among them, input buffered ATM switch is the most simple, cheap and popular switch architecture but it exhibits limited throughput performance due to head of line blocking (HOL) conflict. This problem occurs because of the contention

Kamaruzzaman Seman; Muhammad Waqas; Eng Teik Kai

2000-01-01

415

Glycerol acetals as anti-freezing additives for biodiesel.  

PubMed

Glycerol acetals from butanal, pentanal, hexanal, octanal and decanal were prepared with the use of Amberlyst-15 acid resin as catalyst. The glycerol conversion decreases with the size of the hydrocarbon chain. This fact has been associated with formation of micelles and aggregates of the aldehyde to minimize the interaction between the polar glycerol molecule with the hydrocarbon chain. The Z+E mixture of the acetals with five and six-member rings were produced in all cases. The distribution of the acetal isomers varied with the reaction time, especially for the long chain aldehydes. Addition of 5 vol.% of the butanal-glycerol acetal reduced the pour point of animal fat biodiesel (methyl ester) from 18 to 13 degrees C. The decrease in the pour point of the glycerol acetals-biodiesel mixtures were dependent on the size of the hydrocarbon chain and the percent blended. PMID:20304633

Silva, Paulo H R; Gonçalves, Valter L C; Mota, Claudio J A

2010-08-01

416

Saline catholytes as alternatives to phosphate buffers in microbial fuel cells.  

PubMed

Highly saline solutions were examined as alternatives to chemical buffers in microbial fuel cells (MFCs). The performance of two-chamber MFCs with different concentrations of saline solutions in the cathode chamber was compared to those with a buffered catholyte (50mM PBS). The use of a NaCl catholyte improved the CE to 43-60% (28% with no membrane) due to a reduction in oxygen transfer into the anolyte. The saline catholyte also reduced the membrane and solution resistance to 23? (41? without a membrane). The maximum power density of 491mW/m(2) (240mM NaCl) was only 17% less than the MFC with 50mM PBS. The decrease in power output with highest salinity was due to reduced proton transfer due to the ion exchange membrane, and pH changes in the two solutions. These results show that MFC performance can be improved by using a saline catholyte without pH control. PMID:23433978

Ahn, Yongtae; Logan, Bruce E

2013-03-01

417

Mechanical Properties and a Physical-Chemical Analysis of Acetate Yarns  

Microsoft Academic Search

Cellulose acetate used in the manufacture of acetate yarns is commonly obtained from cotton-linters or wood-pulp cellulose. Varying in the origin and in the manufacturer, cellulose acetate often differs in its processability. The paper belongs to the investigation the properties of acetate yarns manufactured of the cellulose acetate varied in its origin and manufactured by different suppliers. Mechanical properties (including

R. emaitaitien?; A. Vitkauskas

418

Factors affecting constancy of acetate concentration and correct determination of methanogenic activity in pH-stat experiments.  

PubMed

The determination of methanogenic activity with a pH-stat titration bioassay is evaluated utilising a mathematical model of this system. For given kinetic parameters and experimental conditions the model calculates the development of titrant flow and acetate concentration during experiments. Simulations of experiments under various conditions are compared. They show that the original method inherently causes a strong drift of acetate concentration during the experiments and a misestimation of methanogenic activity. As a solution to these disadvantages the addition of sodium hydroxide to the titrant and a careful control of pH during flushing the reactor with gas prior to the experiment are recommended. In this way a better constancy of acetate concentration and a more accurate determination of methanogenic activity should be achievable. The accuracy of this method is limited by the stability of pH-electrode calibration parameters. PMID:14640207

Mösche, M; Meyer, U

2003-01-01

419

Gilliam County Riparian Buffers; 2003-2004 Annual Reports.  

SciTech Connect

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.

Coiner, Josh (Gilliam Soil and Water Conservation District, Condon, OR)

2004-06-01

420

Monitoring Liverworts to Evaluate the Effectiveness of Hydroriparian Buffers  

NASA Astrophysics Data System (ADS)

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.

Higgins, Kellina L.; Yasué, Maï

2014-01-01

421

Selective deprotection of acetals with Me3SiCH2MgCl. Peterson-type olefination of acetals  

PubMed

By employing the chelation strategy, treatment of an acetal of a contiguous diol with Me3SiCH2MgCl liberates the corresponding diol regioselectively. In addition, acetals of different structural variety are transformed upon treatment with Me3SiCH2MgCl and ZnI2 into the corresponding olefination products in good yield. PMID:10959876

Chiang; Chen; Hsieh; Luh

2000-07-28

422

Wasco Riparian Buffer Project, Annual Report 2003-2004.  

SciTech Connect

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.

Graves, Ron

2003-07-01

423

A Mathematical Model of Tumour and Blood pHe Regulation: The HCO3??CO2 Buffering System  

PubMed Central

Malignant tumours are characterised by a low, acidic extracellular pH (pHe) which facilitates invasion and metastasis. Previous research has proposed the potential benefits of manipulating systemic pHe, and recent experiments have highlighted the potential for buffer therapy to raise tumour pHe, prevent metastases, and prolong survival in laboratory mice. To examine the physiological regulation of tumour buffering and investigate how perturbations of the buffering system (via metabolic/respiratory disorders or changes in parameters) can alter tumour and blood pHe, we develop a simple compartmentalised ordinary differential equation model of pHe regulation by the HCO3??CO2 buffering system. An approximate analytical solution is constructed and used to carry out a sensitivity analysis, where we identify key parameters that regulate tumour pHe in both humans and mice. From this analysis, we suggest promising alternative and combination therapies, and identify specific patient groups which may show an enhanced response to buffer therapy. In addition, numerical simulations are performed, validating the model against well-known metabolic/respiratory disorders and predicting how these disorders could change tumour pHe. PMID:21167185

Martin, Natasha K.; Gaffney, Eamonn A.; Gatenby, Robert A.; Gillies, Robert J.; Robey, Ian F.; Maini, Philip K.

2011-01-01

424

Oxidation of Indole-3-acetic Acid and Oxindole-3-acetic Acid to 2,3-Dihydro-7-hydroxy-2-oxo-1H Indole-3-acetic Acid-7?-O-?-d-Glucopyranoside in Zea mays Seedlings 1  

PubMed Central

Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7?-O-?-d-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid ? Oxindole-3-acetic acid ? 7-Hydroxyoxindole-3-acetic acid ? 7-Hydroxyoxindole-3-acetic acid-glucoside. PMID:11540902

Nonhebel, Heather M.; Bandurski, Robert S.

1984-01-01

425

Buffer layers for REBCO films for use in superconducting devices  

SciTech Connect

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.

Goyal, Amit; Wee, Sung-Hun

2014-06-10

426

Enhanced adhesion for LIGA microfabrication by using a buffer layer  

DOEpatents

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).

Bajikar, Sateesh S. (San Jose, CA); De Carlo, Francesco (Darien, IL); Song, Joshua J. (Naperville, IL)

2001-01-01

427

Micelles Protect and Concentrate Activated Acetic Acid  

NASA Astrophysics Data System (ADS)

As more and more exoplanets are discovered and the habitability of such planets is considered, one can turn to searching for the origin of life on Earth in order to better understand what makes a habitable planet. Activated acetic acid, or methyl thioacetate, has been proposed to be central to the origin of life on Earth, and also as an important energy currency molecule in early cellular evolution. We have investigated the hydrolysis of methyl thioacetate under various conditions. Its uncatalyzed rate of hydrolysis is about three orders of magnitude faster (K = 0.00663 s^-1; 100°C, pH 7.5, concentration = 0.33mM) than published rates for its catalyzed production making it unlikely to accumulate under prebiotic conditions. However, we also observed that methyl thioacetate was protected from hydrolysis when inside its own hydrophobic droplets. We found that methyl thioacetate protection from hydrolysis was also possible in droplets of hexane and in the membranes of nonanoic acid micelles. Thus, the hydrophobic regions of prebiotic micelles and early cell membranes could have offered a refuge for this energetic molecule increasing its lifetime in close proximity to the reactions for which it would be needed. Methyl thioacetate could thus be important for the origin of life on Earth and perhaps for better understanding the potential habitability of other planets.

Todd, Zoe; House, C.

2014-01-01

428

CMOS Circuit Speed and Buffer Optimization  

Microsoft Academic Search

An improved timing model for CMOS combinational logic is presented. The model is based on an analytical solution for the CMOS inverter output response to an input ramp. This model yields a better understanding of the switching behavior of the CMOS inverter than the step-response model by considering the slope of the input waveform. Essentially, the propagation delay is shown

Nils Hedenstierna; Kjell O. Jeppson

1987-01-01

429

A Tight Upper Bound on Online Buffer Management for Multi-Queue Switches with Bicodal Buffers  

NASA Astrophysics Data System (ADS)

The online buffer management problem formulates the problem of queuing policies of network switches supporting QoS (Quality of Service) guarantee. In this paper, we consider one of the most standard models, called multi-queue switches model. In this model, Albers et al. gave a lower bound \\frac{e}{e-1}, and Azar et al. gave an upper bound \\frac{e}{e-1} on the competitive ratio when m, the number of input ports, is large. They are tight, but there still remains a gap for small m. In this paper, we consider the case where m = 2, namely, a switch is equipped with two ports, which is called a bicordal buffer model. We propose an online algorithm called Segmental Greedy Algorithm (SG) and show that its competitive ratio is at most \\frac{16}{13} (\\simeq 1.231), improving the previous upper bound by \\frac{9}{7} (\\simeq 1.286). This matches the lower bound given by Schmidt.

Kobayashi, Koji; Miyazaki, Shuichi; Okabe, Yasuo

430

Poly(vinyl alcohol)-based buffering membranes for isoelectric trapping separations  

E-print Network

H gradient in the MCE. Typically, buffering membranes have been made by copolymerizing acrylamide with Immobiline compounds, which are acidic and basic acylamido buffers. One major problem, however, is that these buffering membranes are not stable when...

Craver, Helen C.

2009-05-15

431

Effects of sorption on biological degradation rates of (2,4-dichlorophenoxy) acetic acid in soils.  

PubMed Central

Three mathematical models were proposed to describe the effects of sorption of both bacteria and the herbicide (2,4-dichlorophenoxy)acetic acid (2,4-D) on the biological degradation rates of 2,4-D in soils. Model 1 assumed that sorbed 2,4-D is not degraded, that only bacteria in solution are capable of degrading 2,4-D in solution, and that sorbed bacteria are not capable of degrading either sorbed or solution 2,4-D. Model 2 stated that only bacteria in the solution phase degrade 2,4-D in solution and that only sorbed bacteria degrade sorbed 2,4-D. Model 3 proposed that sorbed 2,4-D is completely protected from degradation and that both sorbed and solution bacteria are capable of degrading 2,4-D in solution. These models were tested by a series of controlled laboratory experiments. Models 1 and 2 did not describe the data satisfactorily and were rejected. Model 3 described the experimental results quite well, indicating that sorbed 2,4-D was completely protected from biological degradation and that sorbed- and solution-phase bacteria degraded solution-phase 2,4-D with almost equal efficiencies. PMID:3994366

Ogram, A V; Jessup, R E; Ou, L T; Rao, P S

1985-01-01

432

Viscosity-stabilized aqueous solutions  

SciTech Connect

Selected sulfur-containing compounds function as solution viscosity stabilizers in aqueous compositions of solid acrylamide polymers contain a redox couple or components which can produce a redox couple in the presence of the solution. The aqueous compositions are useful in post-primary oil recovery involving the use of thickened fluids as mobility buffers and mobility control agents. Specific examples are thiourea, 2-mercaptoethanol, and sodium n,n-dimethyldithiocarbamate. Improved resistance to thermal and oxidative degradation is obtained. 17 claims.

Bruning, D.D.

1982-03-02

433

Computerized image analysis for acetic acid induced intraepithelial lesions  

NASA Astrophysics Data System (ADS)

Cervical Intraepithelial Neoplasia (CIN) exhibits certain morphologic features that can be identified during a visual inspection exam. Immature and dysphasic cervical squamous epithelium turns white after application of acetic acid during the exam. The whitening process occurs visually over several minutes and subjectively discriminates between dysphasic and normal tissue. Digital imaging technologies allow us to assist the physician analyzing the acetic acid induced lesions (acetowhite region) in a fully automatic way. This paper reports a study designed to measure multiple parameters of the acetowhitening process from two images captured with a digital colposcope. One image is captured before the acetic acid application, and the other is captured after the acetic acid application. The spatial change of the acetowhitening is extracted using color and texture information in the post acetic acid image; the temporal change is extracted from the intensity and color changes between the post acetic acid and pre acetic acid images with an automatic alignment. The imaging and data analysis system has been evaluated with a total of 99 human subjects and demonstrate its potential to screening underserved women where access to skilled colposcopists is limited.

Li, Wenjing; Ferris, Daron G.; Lieberman, Rich W.

2008-03-01

434

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 ...

435

Buffer layers for high-Tc thin films on sapphire  

NASA Technical Reports Server (NTRS)

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.

Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

1992-01-01

436

Alternatives to the gradient in optimal transfer line buffer allocation  

E-print Network

This thesis describes several directions to replace the gradient in James Schor's gradient algorithm to solve the dual problem. The alternative directions are: the variance and standard deviation of buffer levels, the ...

Tanizar, Ketty, 1978-

2004-01-01

437

Formation of amide- and imide-linked degradation products between the peptide drug oxytocin and citrate in citrate-buffered formulations.  

PubMed

Citric acid is widely used to buffer pharmaceutical formulations including protein pharmaceuticals. In accelerated stability studies of the small cyclic peptide oxytocin, we have noted that additional degradation products form when oxytocin is formulated in citrate that do not form in other common buffers such as acetate and phosphate. Using high-pressure liquid chromatography combined with high-resolution and tandem mass spectrometry, we identified these degradation products as amide- and imide-linked adducts of oxytocin and citrate. The site of reaction was shown to be the N-terminal amine of cysteine. The adducts have been found to form for oxytocin formulated in citrate buffer over the pH range of 3-6; the extent of formation is greatest at a pH of 4-4.5. We have additionally identified these same adducts in samples of oxytocin formulated in citrate buffer that had been stored in the dark for 3 months at room temperature. Altogether, these results demonstrate that reaction between citrate and oxytocin leads to the formation of covalent amide- and imide-linked adducts. PMID:21547912

Poole, Robert A; Kasper, Piotr Tomasz; Jiskoot, Wim

2011-07-01

438

Intracellular pH and contraction of isolated rabbit and cat papillary muscle: effect of superfusate buffering.  

PubMed

The influence of external buffering on surface pH (pHs), intracellular pH (pHi) and developed twitch tension was investigated in rabbit and cat papillary muscle. pHs and pHi were measured using single and double-barreled microelectrodes respectively. In 20 mM HEPES buffered solution, steady state pHi is close to that in control CO2/HCO-3 (25 mM HCO-3, 5% CO2) solution. pHs and developed tension also do not differ greatly from their control values. Decreasing the HEPES concentration to 5 mM, at constant external pH, lowers pHs considerably. The surface acidosis is associated with a small intracellular acidification; steady state pHi in 5 mM HEPES is always more acid than that in control CO2/HCO-3. A significant decrease in developed tension is also seen in 5 mM HEPES. Alteration of the superfusion velocity influences pHs only slightly. Stimulation of the muscle at high frequency is shown to increase surface acidification, the extent of which is dependent on the buffer concentration. The conclusion from the present experiments is that in papillary muscle external buffering influences intracellular pH and contraction via its effect on pHs. PMID:3989871

Vanheel, B; de Hemptinne, A; Leusen, I

1985-01-01

439

Selective Cross-Coupling of Organic Halides with Allylic Acetates  

PubMed Central

A general protocol for the coupling of haloarenes with a variety of allylic acetates is presented. Strengths of the method are a tolerance for electrophilic (ketone, aldehyde) and acidic (sulfonamide, trifluoroacetamide) substrates and the ability to couple with a variety of substituted allylic acetates. Secondary alkyl bromides can also be allylated under slightly modified conditions, demonstrating the generality of the approach. Finally, the coupling of a reactive vinyl halide could be achieved by the use of a very hindered ligand and more reactive, branched allylic acetates. PMID:23095043

Anka-Lufford, Lukiana L.; Prinsell, Michael R.

2012-01-01

440

Selective cross-coupling of organic halides with allylic acetates.  

PubMed

A general protocol for the coupling of haloarenes with a variety of allylic acetates is presented. Strengths of the method are a tolerance for electrophilic (ketone, aldehyde) and acidic (sulfonamide, trifluoroacetamide) substrates and the ability to couple with a variety of substituted allylic acetates. Secondary alkyl bromides can also be allylated under slightly modified conditions, demonstrating the generality of the approach. Finally, the coupling of a reactive vinyl halide could be achieved by the use of a very hindered ligand and more reactive, branched allylic acetates. PMID:23095043

Anka-Lufford, Lukiana L; Prinsell, Michael R; Weix, Daniel J

2012-11-16

441

Carbon dioxide in the ocean surface: The homogeneous buffer factor  

USGS Publications Warehouse

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.

Sundquist, E.T.; Plummer, L.N.; Wigley, T.M.L.

1979-01-01

442

Riparian forest buffers in the Chesapeake Bay watershed. Fact sheet  

SciTech Connect

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.

NONE

1995-07-01

443

Buffering PV output during cloud transients with energy storage  

NASA Astrophysics Data System (ADS)

Consideration of the use of the major types of energy storage is attempted in this thesis in order to mitigate the effects of power output transients associated with grid-tied CPV systems due to fast-moving cloud coverage. The approach presented here is to buffer intermittency of CPV output power with an energy storage device (used batteries) purchased cheaply from EV owners or battery leasers. When the CPV is connected to the grid with the proper energy storage, the main goal is to smooth out the intermittent solar power and fluctuant load of the grid with a convenient control strategy. This thesis provides a detailed analysis with appropriate Matlab codes to put onto the grid during the day time a constant amount of power on one hand and on the other, shift the less valuable off-peak electricity to the on-peak time, i.e. between 1pm to 7pm, where the electricity price is much better. In this study, a range of base constant power levels were assumed including 15kW, 20kW, 21kW, 22kW, 23kW, 24kW and 25kW. The hypothesis based on an iterative solution was that the capacity of the battery was increased by steps of 5 while the base supply was decreased by the same step size until satisfactorily results were achieved. Hence, it turned out with the chosen battery capacity of 54kWh coupled to the data from the Amonix CPV 7700 unit for Las Vegas for a 3-month period, it was found that 20kW was the largest constant load the system can supply uninterruptedly to the utility company. Simulated results are presented to show the feasibility of the proposed scheme.

Moumouni, Yacouba

444

Conservation buffer distance estimates for Greater Sage-Grouse: a review  

USGS Publications Warehouse

Distances in this report reflect radii around lek locations because these locations are typically (although not universally) known, and management plans often refer to these locations. Lek sites are most representative of breeding habitats, but their locations are focal points within populations, and as such, protective buffers around lek sites can offer a useful solution for identifying and conserving seasonal habitats required by sage-grouse throughout their life cycle. However, knowledge of local and regional patterns of seasonal habitat use may improve conservation of those important areas, especially regarding the distribution and utilization of nonbreeding season habitats (which may be underrepresented in lek-based designations).

Manier, Daniel J.; Bowen, Zachary H.; Brooks, Matthew L.; Casazza, Michael L.; Coates, Peter S.; Deibert, Patricia A.; Hanser, Steven E.; Johnson, Douglas H.

2014-01-01

445

A Reverse Phase HPLC Method to Determine Six Food Dyes Using Buffered Mobile Phase  

Microsoft Academic Search

A reverse phase high performance liquid chromatographic (HPLC) method to determine six food dyes (Sunset Yellow (E-110), Carminic acid (E-120) Carmoisine (E-122), Amaranth (E-123), Ponceau 4R (E-124) and Erythrosine (E-127) is developed in this paper. The separation was made on a Nova-Pack C18 column using methanol -NaH2PO4\\/Na2HPO4 pH=7 buffer solution 0.1M as mobile phase with an elution gradient system. The

J. J. Berzas-Nevado; C. Guiberteau-Cabanillas; A. M. Contento-Salcedo

1998-01-01

446

The buffer phenomenon in ring-like chains of unidirectionally connected generators  

NASA Astrophysics Data System (ADS)

We introduce a new object, namely, a system of ordinary differential equations which is a mathematical model of a ring-like chain of unidirectionally connected RCL-generators. To study periodic solutions of travelling wave type of this system, some special tricks are used which reduce the existence and stability problems for cycles to the investigation of auxiliary delay equations. Using this approach, we establish that the number of stable travelling waves simultaneously existing in the chain increases unboundedly as the number of links of the chain increases, that is, the well-known buffer phenomenon occurs.

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

2014-08-01

447

Influence of Matrix Polarity on the Properties of Ethylene Vinyl Acetate–Carbon Nanofiller Nanocomposites  

PubMed Central

A series of ethylene vinyl acetate (EVA) nanocomposites using four kinds of EVA with 40, 50, 60, and 70 wt% vinyl acetate (VA) contents and three different carbon-based nanofillers—expanded graphite (EG), multi-walled carbon nanotube (MWCNT), and carbon nanofiber (CNF) have been prepared via solution blending. The influence of the matrix polarity and the nature of nanofillers on the morphology and properties of EVA nanocomposites have been investigated. It is observed that the sample with lowest vinyl acetate content exhibits highest mechanical properties. However, the enhancement in mechanical properties with the incorporation of various nanofillers is the highest for EVA with high VA content. This trend has been followed in both dynamic mechanical properties and thermal conductivity of the nanocomposites. EVA copolymer undergoes a transition from partial to complete amorphousness between 40 and 50 wt% VA content, and this changes the dispersion of the nanofillers. The high VA-containing polymers show more affinity toward fillers due to the large free volume available and allow easy dispersion of nanofillers in the amorphous rubbery phase, as confirmed from the morphological studies. The thermal stability of the nanocomposites is also influenced by the type of nanofiller. PMID:20596353

George, Jinu Jacob

2009-01-01

448

Water in polymer membranes. 4. Raman scattering from cellulose acetate films  

SciTech Connect

Raman scattering was observed from thin film optical waveguides of cellulose acetate exposed to water vapor from 0% to 100% relative humidity (RH), and from dilute solutions of water in methyl acetate. Spectra of cellulose acetate (CA398, 39.8% acetyl) at low RH and cellulose triacetate (CTA) at low and high RH are consistent with the presence of water monomers that are weakly hydrogen bonded to acetyl C=O groups. Differences between the spectra of water in CA398 and CTA at low RH are attributed to sequential hydrogen bonding involving OH groups in CA398. At high RH, CA398 and CTA (to a lesser extent) show bands attributed to water/water interactions that are similar to those found in sequentially hydrogen-bonded hydrates. CA398 films that are annealed at high temperatures exhibit decreased water/water interactions at high RH. Exposure of CA398 films to D/sub 2/O converts > 90% of all polymer OH groups to OD groups. This indicates that water is accessible to nearly all regions of the polymer containing OH groups. Annealing does not alter this accessibility but does reduce the total water content by roughly half, at 100% RH. Hydrogen-bonded C=O groups are associated with a band centered at 1731 cm/sup -1/ which increases in intensity with increasing water content in the film but does not shift in frequency. 38 references, 16 figures, 1 table.

Scherer, J.R.; Bailey, G.F.; Kint, S.; Young, R.; Malladi, D.P.; Bolton, B.

1985-01-17

449

Synthesis of bioactive PMMA bone cement via modification with methacryloxypropyltri-methoxysilane and calcium acetate.  

PubMed

Bone cement consisting of polymethylmethacrylate (PMMA) powder and methylmethacrylate (MMA) liquid is clinically used for fixation of implants such as artificial hip joints. However, it does not show bone-bonding ability, i.e., bioactivity. The lack of bioactivity would be one of factors which cause loosening between the cement and the implant. The present authors recently showed the potential of bioactive PMMA-based bone cement through modification with gamma-methacryloxypropyltrimethoxysilane (MPS) and calcium acetate. In this study, the effects of the kinds of PMMA powder on setting time, apatite formation and compressive strength were investigated in a simulated body fluid (Kokubo solution). The cement modified with calcium acetate calcined at 220 degrees C could set within 15 min when the PMMA powder had an average molecular weight of 100,000 or less. The addition of calcium acetate calcined at 120 degrees C in the PMMA powder required a much longer period for setting. The modified cements formed an apatite layer after soaking in the Kokubo solution within 1 day for cement starting from PMMA powder with a molecular weight of 100,000 or less. Compressive strengths of the modified cements were more than 70 MPa for cements starting from 100,000 and 56,000 in molecular weight. After soaking in Kokubo solution for 7 days, the modified cement consisting of PMMA powder of 100,000 in molecular weight showed a smaller decrease in compressive strength than that consisting of 56,000 in molecular weight. These results indicate that bioactive PMMA cement can be produced with appropriate setting time and mechanical strength when PMMA powders with a suitable molecular weight are used. Such a type of design of bioactive PMMA bone cement leads to a novel development of bioactive material for bone substitutes. PMID:15965740

Mori, A; Ohtsuki, C; Miyazaki, T; Sugino, A; Tanihara, M; Kuramoto, K; Osaka, A

2005-08-01

450

A PROGESTOGEN (CHLORMADINONE ACETATE = CAP) FOR CYCLE CONTROL AND INFERTILITY  

E-print Network

A PROGESTOGEN (CHLORMADINONE ACETATE = CAP) FOR CYCLE CONTROL AND INFERTILITY TREATMENT IN THE MARE, CAP has been used for infertility treatments and cycle control in mares in Austria. In all indications

Paris-Sud XI, Université de

451

SOLVENT EXTRACTION OF WASTEWATERS FROM ACETIC-ACID MANUFACTURE  

EPA Science Inventory

Solvent extraction was evaluated as a potential treatment method for wastewaters generated during the manufacture of acetic acid. Possible goals for an extraction process were considered. For the wastewater samples studied, extraction appeared to be too expensive to be practical ...

452

Porphyria variegata treated with cyproterone acetate and ethinyl estradiol.  

PubMed

The cyclical use of cyproterone acetate and ethinyl estradiol successfully prevented attacks of abdominal pain in a 30-year-old woman suffering from porphyria variegata. Blistering still appeared following light exposure, but possibly to a lesser degree. PMID:6873421

Zachariae, H; Cramers, M

1983-01-01

453

Message communications of particular message types between compute nodes using DMA shadow buffers  

DOEpatents

Message communications of particular message types between compute nodes using DMA shadow buffers includes: receiving a buffer identifier specifying an application buffer having a message of a particular type for transmission to a target compute node through a network; selecting one of a plurality of shadow buffers for a DMA engine on the compute node for storing the message, each shadow buffer corresponding to a slot of an injection FIFO buffer maintained by the DMA engine; storing the message in the selected shadow buffer; creating a data descriptor for the message stored in the selected shadow buffer; injecting the data descriptor into the slot of the injection FIFO buffer corresponding to the selected shadow buffer; selecting the data descriptor from the injection FIFO buffer; and transmitting the message specified by the selected data descriptor through the data communications network to the target compute node.

Blocksome, Michael A. (Rochester, MN); Parker, Jeffrey J. (Rochester, MN)

2010-11-16

454

Formation of caries-like lesions in vitro on the root surfaces of human teeth in solutions simulating plaque fluid.  

PubMed

Lesion formation on root surfaces of human posterior teeth was studied in acetate/lactate buffers with a background electrolyte composition based on plaque fluid analyses. Lesion depth after 28 days at 37 degrees C was measured in relation to: the presence or absence of cementum; the concentration of undissociated buffer; the presence or absence of magnesium ions at plaque fluid concentration. Each factor was evaluated at several values of -log(ion activity product for hydroxyapatite): pI(HA). Solutions were formulated to minimize variation in pH, which varied by < or =0.03 for a given comparison (individual pI(HA)) and by 0.42-0.82 over the range of pI(HA) within experiments. Lesions on surfaces from which cementum had been ground were significantly deeper than on intact surfaces, but this is considered to be due to subsurface mechanical damage and not to a solubility difference. Neither the concentration of undissociated buffer nor the presence of magnesium ions significantly affected lesion depth. Lesion depth was strongly influenced by the correlated variations in pI(HA) and pH. At pI(HA) 54 and 55, only extremely shallow lesions formed. From pI(HA) 56, lesion depth increased with increasing pI(HA). The results confirm that the solubility of the mineral of root tissues is higher than that of hydroxyapatite, but indicate that it is probably lower than suggested by Hoppenbrouwers et al. [Arch Oral Biol 1987;32:319-322]. For calcium concentrations of 3-12 mM, the critical pH for root tissue mineral was calculated as 5.22-5.66 assuming solubility equivalent to pI(HA) 54 and 5.08-5.51 assuming pI(HA) 55. PMID:20699614

Shellis, R P

2010-01-01

455

Bray\\/Kurtz, Mehlich III, AB\\/D and ammonium acetate extractions of P, K and MG in four oklahoma soils  

Microsoft Academic Search

Multi?element soil extraction solutions offer increased convenience in soil testing laboratory operations. The recently developed Mehlich III and ammonium bicarbonate?DTPA multi?element extraction solutions were each compared with the more conventional Bray\\/Kurtz extractant for P determination and with 1N ammonium acetate for K and Mg determinations. The latter two solutions are single and tri?element extractants in current use by the Oklahoma

E. A. Hanlon; G. V. Johnson

1984-01-01

456

Negative Pressure Wound Therapy of Chronically Infected Wounds Using 1% Acetic Acid Irrigation  

PubMed Central

Background Negative-pressure wound therapy (NPWT) induces angiogenesis and collagen synthesis to promote tissue healing. Although acetic acid soaks normalize alkali wound conditions to raise tissue oxygen saturation and deconstruct the biofilms of chronic wounds, frequent dressing changes are required. Methods Combined use of NPWT and acetic acid irrigation was assessed in the treatment of chronic wounds, instilling acetic acid solution (1%) beneath polyurethane membranes twice daily for three weeks under continuous pressure (125 mm Hg). Clinical photographs, pH levels, cultures, and debrided fragments of wounds were obtained pre- and posttreatment. Tissue immunostaining (CD31, Ki-67, and CD45) and reverse transcription-polymerase chain reaction (vascular endothelial growth factor [VEGF], vascular endothelial growth factor receptor [VEGFR]; procollagen; hypoxia-inducible factor 1 alpha [HIF-1-alpha]; matrix metalloproteinase [MMP]-1,-3,-9; and tissue inhibitor of metalloproteinase [TIMP]) were also performed. Results Wound sizes tended to diminish with the combined therapy, accompanied by drops in wound pH (weakly acidic or neutral) and less evidence of infection. CD31 and Ki-67 immunostaining increased (P<0.05) post-treatment, as did the levels of VEGFR, procollagen, and MMP-1 (P<0.05), whereas the VEGF, HIF-1-alpha, and MMP-9/TIMP levels declined (P<0.05). Conclusions By combining acetic acid irrigation with negative-pressure dressings, both the pH and the size of chronic wounds can be reduced and infections be controlled. This approach may enhance angiogenesis and collagen synthesis in wounds, restoring the extracellular matrix. PMID:25606491

Lee, Byeong Ho; Lee, Hye Kyung; Kim, Hyoung Suk; Moon, Min Seon; Suh, In Suck

2015-01-01

457

Diethylene-triamine-penta-acetate administration protocol for radiological emergency medicine in nuclear fuel reprocessing plants.  

PubMed

Inhalation therapy of diethylene-triamine-penta-acetate (DTPA) should be initiated immediately to workers who have significant incorporation of plutonium, americium or curium in the nuclear fuel reprocessing plant. A newly designed electric mesh nebulizer is a small battery-operated passive vibrating mesh device, in which vibrations in an ultrasonic horn are used to force drug solution through a mesh of micron-sized holes. This nebulizer enables DTPA administration at an early stage in the event of a radiation emergency from contamination from the above radioactive metals. PMID:18274997

Jin, Yutaka

2008-01-01

458

Bio-composites based on cellulose acetate and kenaf fibers: Processing and properties  

NASA Astrophysics Data System (ADS)

Research on bio-composites is important because of its positive environmental impact. In this study, bio-composites based on plasticised cellulose acetate and kenaf fibers were prepared by solution casting and compression moulding methods. The fibers were chemically treated to remove lignin, hemicellulose and impurities. Mechanical, morphological and thermal properties of the bio-composites were studied. Introduction of chopped kenaf fibers increased the storage modulus. The flexural storage modulus of the composite was affected with the introduction of moisture. Moisture behaved similar to the effect of plasticiser, it reduced the modulus.

Pang, C.; Shanks, R. A.; Daver, F.

2014-05-01

459

Disposition of eslicarbazepine acetate in the mouse after oral administration.  

PubMed

Eslicarbazepine acetate is a promising antiepileptic drug structurally related to carbamazepine and oxcarbazepine, which is in the final phase of clinical development. The metabolism of eslicarbazepine acetate is clearly species dependent and, in this case, among small laboratory animals, the mouse seems to be the most relevant species to humans. Hence, the aim of this study was to investigate the plasma, brain and liver disposition of eslicarbazepine acetate in mice to better understand its disposition in humans. Adult male CD-1 mice were treated orally with a single dose of eslicarbazepine acetate 350 mg/kg. Blood samples, brain and liver tissues were taken at 0.25, 0.5, 0.75, 1, 2, 4, 6, 10, 16 and 24 h post-dose. Plasma and tissue levels of eslicarbazepine acetate and its metabolites (S-licarbazepine, R-licarbazepine and oxcarbazepine) were assessed by using high-performance liquid chromatography-ultraviolet detection. Both eslicarbazepine acetate and R-licarbazepine concentrations were below the limit of quantification of the assay in all matrices. Eslicarbazepine acetate was rapidly and extensively metabolized to S-licarbazepine (major metabolite), which was oxidized to oxcarbazepine to a small extent. The brain/plasma ratios suggest that the brain exposure to S-licarbazepine and oxcarbazepine was approximately 30% of their total systemic exposure. However, S-licarbazepine crossed the blood-brain barrier (BBB) less efficiently than oxcarbazepine. On the other hand, the liver/plasma ratios support the notion that S-licarbazepine undergoes hepatic accumulation, whereas oxcarbazepine appears to leave this compartment twice as fast as S-licarbazepine. Thus, the diffusion through the BBB is favourable to oxcarbazepine and the liver acts like a deposit of the pharmacologically active metabolite of eslicarbazepine acetate (S-licarbazepine). PMID:18710399

Alves, Gilberto; Figueiredo, Isabel; Castel-Branco, Margarida; Lourenço, Nulita; Falcão, Amílcar; Caramona, Margarida; Soares-da-Silva, Patrício

2008-10-01

460

Acetate transiently inhibits myocardial contraction by increasing mitochondrial calcium uptake.  

PubMed

BackgroundThere is a close relationship between cardiovascular disease and cardiac energy metabolism, and we have previously demonstrated that palmitate inhibits myocyte contraction by increasing Kv channel activity and decreasing the action potential duration. Glucose and long chain fatty acids are the major fuel sources supporting cardiac function; however, cardiac myocytes can utilize a variety of substrates for energy generation, and previous studies demonstrate the acetate is rapidly taken up and oxidized by the heart. In this study, we tested the effects of acetate on contractile function of isolated mouse ventricular myocytes.ResultsAcute exposure of myocytes to 10 mM sodium acetate caused a marked, but transient, decrease in systolic sarcomere shortening (1.49¿±¿0.20% vs. 5.58¿±¿0.49% in control), accompanied by a significant increase in diastolic sarcomere length (1.81¿±¿0.01 ¿m vs. 1.77¿±¿0.01 ¿m in control), with a near linear dose response in the 1¿10 mM range. Unlike palmitate, acetate caused no change in action potential duration; however, acetate markedly increased mitochondrial Ca2+ uptake. Moreover, pretreatment of cells with the mitochondrial Ca2+ uptake blocker, Ru-360 (10 ¿M), markedly suppressed the effect of acetate on contraction.ConclusionsLehninger and others have previously demonstrated that the anions of weak aliphatic acids such as acetate stimulate Ca2+ uptake in isolated mitochondria. Here we show that this effect of acetate appears to extend to isolated cardiac myocytes where it transiently modulates cell contraction. PMID:25488103

Schooley, James F; Namboodiri, Aryan M A; Cox, Rachel T; Bünger, Rolf; Flagg, Thomas P

2014-12-01

461

Acetic acid pulping of wheat straw under atmospheric pressure  

Microsoft Academic Search

Atmospheric acetic acid pulping of wheat straw was carried out. Pulping conditions and their effects on pulp properties were\\u000a investigated in detail, and a comparison between acetic acid (AcOH) pulp and soda-anthraquinone (AQ) pulps of wheat straw\\u000a was made of the chemical composition, strength, and fiber morphology of the pulps. Wheat straw was successfully pulped and\\u000a fractionated into pulp (cellulose),

Xue-Jun Pan; Yoshihiro Sano

1999-01-01

462

Microorganisms having enhanced resistance to acetate and methods of use  

SciTech Connect

The present invention provides isolated or genetically modified strains of microorganisms that display enhanced resistance to acetate as a result of increased expression of a sodium proton antiporter. The present invention also provides methods for producing such microbial strains, as well as related promoter sequences and expression vectors. Further, the present invention provides methods of producing alcohol from biomass materials by using microorganisms with enhanced resistance to acetate.

Brown, Steven D; Yang, Shihui

2014-10-21

463

Proteome analysis of Acetobacter pasteurianus during acetic acid fermentation.  

PubMed

Acetic acid bacteria (AAB) are Gram-negative, strictly aerobic microorganisms that show a unique resistance to ethanol (EtOH) and acetic acid (AcH). Members of the Acetobacter and Gluconacetobacter genera are capable of transforming EtOH into AcH via the alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) enzymes and are used for the industrial production of vinegar. Several mechanisms have been proposed to explain how AAB resist high concentrations of AcH, such as the assimilation of acetate through the tricarboxylic acid (TCA) cycle, the export of acetate by various transporters and modifications of the outer membrane. However, except for a few acetate-specific proteins, little is known about the global proteome responses to AcH. In this study, we used 2D-DIGE to compare the proteome of Acetobacter pasteurianus LMG 1262(T) when growing in glucose or ethanol and in the presence of acetic acid. Interesting protein spots were selected using the ANOVA p-value of 0.05 as threshold and 1.5-fold as the minimal level of differential expression, and a total of 53 proteins were successfully identified. Additionally, the size of AAB was reduced by approximately 30% in length as a consequence of the acidity. A modification in the membrane polysaccharides was also revealed by PATAg specific staining. PMID:22155126

Andrés-Barrao, Cristina; Saad, Maged M; Chappuis, Marie-Louise; Boffa, Mauro; Perret, Xavier; Ortega Pérez, Ruben; Barja, François

2012-03-16

464

Ammonia-free chemical bath deposition of nanocrystalline ZnS thin film buffer layer for solar cells  

Microsoft Academic Search

In this work, we prepared zinc sulfide thin films on glass substrates by ammonia-free chemical bath deposition method using thioacetamide as the sulfide source and Ethylene Diamine Tetra Acetic Acid disodium salt as the complexing agent in a solution of pH=6.0. Thin films of ZnS with different thicknesses of 18–450 nm were prepared. The effect of film thickness and annealing temperature

Alireza Goudarzi; Ghaffar Motedayen Aval; Reza Sahraei; Hiva Ahmadpoor

2008-01-01

465

Functionalization of ethylene vinyl acetate with antimicrobial chlorhexidine hexametaphosphate nanoparticles  

PubMed Central

Ethylene vinyl acetate (EVA) is in widespread use as a polymeric biomaterial with diverse applications such as intravitreal devices, catheters, artificial organs, and mouthguards. Many biomaterials are inherently prone to bacterial colonization, as the human body is host to a vast array of microbes. This can lead to infection at the biomaterial’s site of implantation or application. In this study, EVA was coated with chlorhexidine (CHX) hexametaphosphate (HMP) nanoparticles (NPs) precipitated using two different reagent concentrations: CHX-HMP-5 (5 mM CHX and HMP) and CHX-HMP-0.5 (0.5 mM CHX and HMP). Data gathered using dynamic light scattering, transmission electron microscopy, and atomic force microscopy indicated that the NPs were polydisperse, ~40–80 nm in diameter, and aggregated in solution to form clusters of ~140–200 nm and some much larger aggregates of 4–5 ?M. CHX-HMP-5 formed large deposits on the polymer surface discernible using scanning electron microscopy, whereas CHX-HMP-0.5 did not. Soluble CHX was released by CHX-HMP-5 NP-coated surfaces over the experimental period of 56 days. CHX-HMP-5 NPs prevented growth of methicillin-resistant Staphylococcus aureus when applied to the polymer surfaces, and also inhibited or prevented growth of Pseudomonas aeruginosa with greater efficacy when the NP suspension was not rinsed from the polymer surface, providing a greater NP coverage. This approach may provide a useful means to treat medical devices fabricated from EVA to render them resistant to colonization by pathogenic microorganisms. PMID:25206305

Wood, Natalie J; Maddocks, Sarah E; Grady, Helena J; Collins, Andrew M; Barbour, Michele E

2014-01-01

466

Mapping Soil pH Buffering Capacity of Selected Fields  

NASA Technical Reports Server (NTRS)

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.