These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
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

Separation of Trivalent Actinides from Lanthanides in an Acetate Buffer Solution Using Cyanex 301  

SciTech Connect

The separation of trivalent actinides from the lanthanides using the active extractant in the Cyanex 301 reagent, bis(2,4,4-trimethylpentyl)dithiophosphinic acid, was studied. Specifically, the extractant was studied for an ammonium acetate/acetic acid buffered feed that would result from a transuranic separation process utilizing an ammonium acetate strip solution. Separation factors of 241Am from 154Eu with this extractant, as a function of total acetate concentration and pH, have been measured. Additionally, the extraction behavior of stable La, Ce, Pr, Nd, Sm, and Eu was measured. Separation factors were typically very high for Am from Eu at a pH ranging from 3.8 to 5.8 and a total acetate concentration ranging from 0.2 M to 1.0 M. However, separation factors across the lanthanide series varied considerably and resulted in separation of the lighter lanthanides from the heavier lanthanides at the higher pH’s.

Jack D. Law; Dean R. Peterman; Terry A. Todd; Richard D. Tillotson

2006-05-01

3

Second Dissociation Constant of Bis[(2-hydroxyethyl)amino]acetic Acid (BICINE) and pH of Its Buffer Solutions from 5 to 55 °C  

Microsoft Academic Search

The values of the second dissociation constant, K\\u000a 2, and related thermodynamic quantities of the ampholyte bis[(2-hydroxyethyl)amino]acetic acid (BICINE) have been determined at temperatures from 5 to 55 ?C. The pH values of six equimolal buffer solutions, and four buffer solutions having ionic strengths (I = 0.16 mol?kg?1) similar to those in blood plasma, have been evaluated at 12 temperatures

Lakshmi N. Roy; Rabindra N. Roy; Cole E. Denton; Sean R. LeNoue; Chandra N. Roy; Shahaf Ashkenazi; Thomas B. Williams; Daniel R. Church; Michael S. Fuge; Kartik N. Sreepada

2006-01-01

4

Calculation of stoichiometric dissociation constants of monoprotic carboxylic acids in dilute aqueous sodium or potassium chloride solutions and p[m(H(+))] values for acetate and formate buffers at 25 degrees C.  

PubMed

Equations are given for calculation of the stoichiometric (molality scale) dissociation constants, K(m), of weak acids in dilute aqueous electrolyte solutions at 298.15 K from the thermodynamic dissociation constant, K(a), of the acid and the ionic strength, I(m), of the solution. The equations for K(m) were based on the single-ion activity coefficient equations of the Hückel type. The equations were tested with the conductivity data for formic, acetic, propionic, n-butyric, lactic, chloroacetic, alpha-crotonic and cyanoacetic acids, and with data measured by Harned cells for formic, acetic, propionic, n-butyric and glycolic acids. These data were taken from the literature. According to these tests, K(m) can be obtained by the Hückel method within experimental error at least up to I(m) of about 0.1 mol kg(-1). On the basis of the equations for K(m), it is suggested p(m(H)) values {p(m(H))=-lg[m(H(+))/(mol kg(-1))] where m refers to the molality} for buffer solutions containing acetic or formic acid. A new calibration method is suggested for glass electrode cells, and this method is based on the p(m(H)) values instead of pH values (pH=-lg[a(H(+))] where a refers to the activity). PMID:18968046

Partanen, J I

2000-08-16

5

Concentrating aqueous acetate solutions with tertiary amines  

E-print Network

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

Lee, Champion

2012-06-07

6

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

NASA Astrophysics Data System (ADS)

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

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

2005-05-01

7

Effects of Acetate Buffer Concentration on Lysozyme Solubility.  

National Technical Information Service (NTIS)

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 stu...

E. L. Forsythe, M. L. Pusey

1996-01-01

8

Conductance of Dilute Sodium Acetate Solutions to 469 K and of Acetic Acid and Sodium Acetate\\/Acetic Acid Mixtures to 548 K and 20 MPa  

Microsoft Academic Search

In order to obtain accurate association constants for sodium acetate, a very precise flow method was used to measure the electrical conductivity of dilute aqueous solutions of sodium acetate at ambient conditions and 469 K and 20 MPa. Measurements at ambient conditions, 469 and 548 K and 20 MPa, were also made on sodium acetate\\/acetic acid mixtures and acetic acid.

G. H. Zimmerman; R. H. Wood

2002-01-01

9

Antimicrobial activity of borate-buffered solutions.  

PubMed Central

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

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

1986-01-01

10

Influence of Medium Buffering Capacity on Inhibition of Saccharomyces cerevisiae Growth by Acetic and Lactic Acids  

PubMed Central

Acetic acid (167 mM) and lactic acid (548 mM) completely inhibited growth of Saccharomyces cerevisiae both in minimal medium and in media which contained supplements, such as yeast extract, corn steep powder, or a mixture of amino acids. However, the yeast grew when the pH of the medium containing acetic acid or lactic acid was adjusted to 4.5, even though the medium still contained the undissociated form of either acid at a concentration of 102 mM. The results indicated that the buffer pair formed when the pH was adjusted to 4.5 stabilized the pH of the medium by sequestering protons and by lessening the negative impact of the pH drop on yeast growth, and it also decreased the difference between the extracellular and intracellular pH values (?pH), the driving force for the intracellular accumulation of acid. Increasing the undissociated acetic acid concentration at pH 4.5 to 163 mM by raising the concentration of the total acid to 267 mM did not increase inhibition. It is suggested that this may be the direct result of decreased acidification of the cytosol because of the intracellular buffering by the buffer pair formed from the acid already accumulated. At a concentration of 102 mM undissociated acetic acid, the yeast grew to higher cell density at pH 3.0 than at pH 4.5, suggesting that it is the total concentration of acetic acid (104 mM at pH 3.0 and 167 mM at pH 4.5) that determines the extent of growth inhibition, not the concentration of undissociated acid alone. PMID:11916676

Thomas, K. C.; Hynes, S. H.; Ingledew, W. M.

2002-01-01

11

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

SciTech Connect

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

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

2010-09-15

12

Calculation of stoichiometric dissociation constants of monoprotic carboxylic acids in dilute aqueous sodium or potassium chloride solutions and p[ m(H +)] values for acetate and formate buffers at 25°C  

Microsoft Academic Search

Equations are given for calculation of the stoichiometric (molality scale) dissociation constants, Km, of weak acids in dilute aqueous electrolyte solutions at 298.15 K from the thermodynamic dissociation constant, Ka, of the acid and the ionic strength, Im, of the solution. The equations for Km were based on the single-ion activity coefficient equations of the Hückel type. The equations were

Jaakko I. Partanen

2000-01-01

13

Chemical solution deposition of textured BaTiO3 buffer layers on cube textured Ni-tapes fabricated from commercially available nickel  

Microsoft Academic Search

Barium titanate buffer layers were successfully applied to cube textured Ni-tapes fabricated from commercially available nickel by a chemical solution deposition route. Barium acetate solutions in anhydrous acetic acid were mixed with bis(pentane-2,4-dionato)-titanium(IV)-oxide dissolved in methanol. A slight excess of acetic acid anhydride assured the anhydrous medium. The precursor solution was spin-coated to the Ni-substrate. Heat treatment at 1 000°C

O Staller; G Gritzner

2008-01-01

14

Self-association of daunomycin antibiotic in various buffer solutions  

Microsoft Academic Search

The self-association of an antitumor antibiotic, daunomycin (DAU), in various buffer solutions, including water-salt solutions,\\u000a phosphate buffer, HEPES, and TRIS, was studied by 1D and 2D 1H NMR spectroscopy at 500 MHz. The two-dimensional NOESY spectra and the concentration and temperature dependences of the\\u000a chemical shifts of antibiotic protons in the solvents studied showed that the self-association parameters of DAU

M. P. Evstigneev; V. V. Khomich; D. B. Davies

2006-01-01

15

A New Strategy to Stabilize Oxytocin in Aqueous Solutions: I. The Effects of Divalent Metal Ions and Citrate Buffer  

Microsoft Academic Search

In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of\\u000a aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na+ and K+) and divalent metal ions (Ca2+, Mg2+, and Zn2+) were tested all as chloride salts. The effect of combinations of buffers and metal ions on the stability of

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

2011-01-01

16

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

Federal Register 2010, 2011, 2012, 2013

...Levomethadyl Acetate Hydrochloride) Oral Solution, 10 Milligrams/Milliliter, Was Not...acetate hydrochloride (HCl)) oral solution, 10 milligrams (mg)/milliliter...ANDAs) for levomethadyl acetate HCl oral solution, 10 mg/mL, if all other legal...

2011-06-06

17

Cathodic Hydrogen Evolution from Aqueous Solutions of Acetic Acid  

Microsoft Academic Search

In continuation of the work on establishing hydrogen donors in the hydrogen evolution reaction from different acid molecules, cathodic evolution of hydrogen on silver is investigated from solutions of monobasic acetic acid with the aim to establish the origin of reduced hydrogen. Solutions of 0.2 M acetic acid with 0.2 M perchloric acid, neutralized to different pH values by NaOH,

V. Marinovi?; A. R. Despi?

2004-01-01

18

Permeability of cellulose acetate membranes to selected solutes  

Microsoft Academic Search

The permeability of cellulose 2.5-acetate films to several electrolytes and nonelectrolytes was measured. Permeabilities were determined by a desorption-rate method in which diffusion and distribution coefficients were measured. The rejection of the same solutes by modified cellulose acetate membranes in reverse osmosis experiments was also measured. A comparison was made between intrinsic water and solute permeabilities and the reverse osmosis

H. K. Lonsdale; B. P. Cross; F. M. Graber; C. E. Milstead

1971-01-01

19

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

20

Evaluation of Chromate as Dezincification Inhibitor for ?-brass (Cu\\/Zn : 64\\/36) in 3% Chloride Buffer Solutions  

Microsoft Academic Search

The inhibition behavior of chromate ions towards corrosion and dezincification of ?- brass (Cu\\/Zn: 64\\/36) in acetate buffer solutions (pH 2.4, 7.0 and 8.5) containing 3% sodium chloride was studied. Weight loss and solution analysis were used for a long period (four weeks) and electrochemical polarization for a short period (one hour). Chromate accelerated corrosion and dezincification at pH 2.4

H. H. Rehan; N. A. Al-Moubarak; H. A. Al-Rafai

2003-01-01

21

Capillary array electrophoretic NMR of proteins in biological buffer solutions.  

PubMed

The capillary array electrophoretic NMR (CA-ENMR) was developed to study protein mixtures in biological buffer solutions of high ionic strength. By enhancing the strength of the effective electric field across the sample, the technique permits the detection of the electrophoretic motion of 1 mM lysozyme in 50 mM NaH(2)PO(4) aqueous solution, which was previously not achievable using conventional ENMR. Heat-induced convection was dramatically reduced by blocking convective current loops and by improving the efficiency of heat exchange. Thus, the capability of ENMR study of electrolyte solutions was extended from low to high ionic strength. In addition, capillary walls reduced rf-induced electrical eddy current, thereby maintaining good probe Q factors. Because of its parallel configuration to the static magnetic field, the capillary array chamber produced no susceptibility distortions of the ENMR signal. The technique offers great potential in characterizing multiple protein conformations and protein interactions in solution. PMID:10579960

He, Q; Liu, Y; Sun, H; Li, E

1999-12-01

22

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

23

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

PubMed

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

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

2012-01-01

24

Electrochemical behaviour of silver in borate buffer solutions  

NASA Astrophysics Data System (ADS)

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

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

2004-01-01

25

Effect of buffered solutions and sulfate on vegetative and sexual development in gametophytes of Pteridium aquilinum  

Microsoft Academic Search

Experiments were performed to determine effects of buffered solutions (0.01 M) on vegetative development and fertilization of gametophytes of Pteridium aquilinum. Buffered solutions were used to simulate exposures to acidic precipitation up to 3.5 h. Flagellar movement of sperm was reduced at buffer pH levels below 5.8. Specifically, longevity of motility was reduced so that no movements were observed 8

Lance S. Evans; Donna M. Bozzone

1977-01-01

26

Determination of the Components of Reagent and Buffer Solutions by Flame Photometry.  

National Technical Information Service (NTIS)

An analytical process has been worked out for quantitative determination by flame photometry of sodium-potassium tartrate in a Fehling II and Nylander solution, potassium dehydrophosphate, and sodium monohydrophosphate in buffer phosphate solutions used r...

M. Sarsunova, S. Szuesova

1971-01-01

27

Biocompatibility and tolerability of a purely bicarbonate-buffered peritoneal dialysis solution  

Microsoft Academic Search

BACKGROUND: Novel peritoneal dialysis solutions are characterized by a minimal content of glucose degradation products and a neutral pH. Many studies have shown the biocompatibility of neutral lactate-buffered solutions; however, until now, the effect of purely bicarbonate-buffered solutions has not been intensively studied in vivo. METHODS: This study was an open label, prospective, crossover multicenter trial to investigate the biocompatibility

L. Weiss; B. Stegmayr; G. Malmsten; M. Tejde; H. Hadimeri; C. E. Siegert; J. Ahlmen; R. Larsson; B. Ingman; O. Simonsen; H. W. van Hamersvelt; A. C. Johansson; B. Hylander; M. Mayr; P. H. Nilsson; P. O. Andersson; T. De Los Rios

2009-01-01

28

Low-temperature solution-processed metal oxide buffer layers fulfilling large area production requirements  

NASA Astrophysics Data System (ADS)

This paper is a review of our previous work on the field of low temperature, solution processed metal oxide buffer layers published in various journals. Our work focuses on zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) as n-type and molybdenum oxide (MoO3) as p-type solution processed buffer layer. In addition to that, we investigate the surface modification of AZO using phosphonic acid-anchored aliphatic and fullerene self assembled monolayers (SAMs).

Stubhan, T.; Litzov, I.; Li, Ning; Wang, H. Q.; Krantz, J.; Machui, F.; Steidl, M.; Oh, H.; Matt, G. J.; Brabec, C. J.

2012-09-01

29

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

PubMed

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

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

2011-05-01

30

Influence of an acetate- and a lactate-based balanced infusion solution on acid base physiology and hemodynamics: an observational pilot study  

PubMed Central

Background The current pilot study compares the impact of an intravenous infusion of Ringer’s lactate to an acetate-based solution with regard to acid–base balance. The study design included the variables of the Stewart approach and focused on the effective strong ion difference. Because adverse hemodynamic effects have been reported when using acetate buffered solutions in hemodialysis, hemodynamics were also evaluated. Methods Twenty-four women who had undergone abdominal gynecologic surgery and who had received either Ringer’s lactate (Strong Ion Difference 28 mmol/L; n?=?12) or an acetate-based solution (Strong Ion Difference 36.8 mmol/L; n?=?12) according to an established clinical protocol and its precursor were included in the investigation. After induction of general anesthesia, a set of acid–base variables, hemodynamic values and serum electrolytes was measured three times during the next 120 minutes. Results Patients received a mean dose of 4,054?±?450 ml of either one or the other of the solutions. In terms of mean arterial blood pressure and norepinephrine requirements there were no differences to observe between the study groups. pH and serum HCO3- concentration decreased slightly but significantly only with Ringer’s lactate. In addition, the acetate-based solution kept the plasma effective strong ion difference more stable than Ringer’s lactate. Conclusions Both of the solutions provided hemodynamic stability. Concerning consistency of acid base parameters none of the solutions seemed to be inferior, either. Whether the slight advantages observed for the acetate-buffered solution in terms of stability of pH and plasma HCO3- are clinically relevant, needs to be investigated in a larger randomized controlled trial. PMID:22769740

2012-01-01

31

Differential effect of buffering agents on the crystallization of gemcitabine hydrochloride in frozen solutions.  

PubMed

The purpose of this study was to evaluate the differential effect of buffering agents on the crystallization of gemcitabine hydrochloride (GHCl) in frozen solutions. Four buffering agents, viz. citric acid (CA), malic acid (MA), succinic acid (SA) and tartaric acid (TA) were selected and their effect on GHCl crystallization was monitored using standard DSC and low temperature XRD. Onset of GHCl crystallization during heating run in DSC was measured to compare the differential effect of buffering agents. Glass transition temperature (Tg'), unfrozen water content in the freeze concentrate and crystallization propensity of the buffering agents was also determined for mechanistic understanding of the underlying effects. CA and MA inhibited while SA facilitated crystallization of GHCl even at 25 mM concentration. Increasing the concentration enhanced their effect. However, TA inhibited GHCl crystallization at concentrations <100mM and facilitated it at concentrations ?100 mM. Lyophilization of GHCl with either SA or TA yielded elegant cakes, while CA and MA caused collapse. Tg' failed to explain the inhibitory effects of CA, MA and TA as all buffering agents lowered the Tg' of the system. Differential effect of buffering agents on GHCl crystallization could be explained by consideration of two opposing factors: (i) their own crystallization tendency and (ii) unfrozen water content in the freeze concentrate. In conclusion, it was established that API crystallization in frozen solution is affected by the type and concentration of the buffering agents. PMID:24836665

Patel, Mehulkumar; Munjal, Bhushan; Bansal, Arvind K

2014-08-25

32

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

NSDL National Science Digital Library

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

Wiles, Laura K.

2009-08-15

33

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

34

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

EPA Science Inventory

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

35

Hemodiafiltration with Endogenous Reinfusion with and without Acetate-Free Dialysis Solutions: Effect on ESA Requirement  

Microsoft Academic Search

Background: Hemofiltrate reinfusion (HFR) is a form of hemodiafiltration (HDF) in which replacement fluid is constituted by ultrafiltrate from the patient ‘regenerated’ through a cartridge containing hydrophobic styrene resin. Bicarbonate-based dialysis solutions (DS) used in routine hemodialysis and HDF contain small quantities of acetate (3–5 mM) as a stabilizing agent, one of the major causes of intradialytic hypotension. Acetate-free (AF)

P. G. Bolasco; P. M. Ghezzi; A. Serra; L. Corazza; S. Murtas; M. Mascia; M. Cossu; R. Ferrara; G. Cogoni; F. Cadinu; D. Casu; B. Contu; M. Passaghe; T. Ghisu; M. Ganadu; F. Logias

2011-01-01

36

Effect of fluoride in phosphate buffer solution on bonding to artificially carious enamel.  

PubMed

The purpose of the present study was to evaluate the effect of fluoride on resin bonding to artificially carious enamel. Specimens from demineralized human enamel sections were prepared using two commercially available adhesives (Clearfil SE Bond, Kuraray; Single Bond, 3M) and a composite resin (Clearfil AP-X, Kuraray) according to manufacturers' instructions. They were then immersed in phosphate buffered saline solution with varied fluoride concentrations at 0, 0.1, 0.5, 1, and 10 ppm. After immersion in each solution for one, three, or seven days, microshear bond strength was measured. The bond strengths of both adhesive systems to artificially carious enamel significantly increased after immersion in fluoride-phosphate buffer solution. Based on the findings obtained, we thus proposed not to remove the white enamel lesions for bonding in the clinic. They might be preserved and treated using fluoride applications. PMID:18203474

Wang, Hao; Shimada, Yasushi; Tagami, Junji

2007-09-01

37

Comparison of three buffer solutions for amino acid derivatization and following analysis by liquid chromatography electrospray mass spectrometry.  

PubMed

For reversed phase separation amino acids are usually derivatized. Several derivatization reactions are carried out at basic pH. In the present work, influence of three basic buffer solutions on liquid chromatography electrospray ionization mass-spectrometric (LC-ESI-MS) analysis of amino acid derivatives was studied. Borate buffer--the most common derivatization buffer--was found to influence ESI ionization up to 23 min retention time. For 9-fluorenylmethylmethoxycarbonyl chloride (Fmoc-Cl derivatization) carbonate buffer should be preferred as it provides higher responses. Hexafluoroisopropanol (HFIP) buffer improves chromatographic peak shapes and responses for diethyl ethoxymethylenemalonate (DEEMM) derivatives. PMID:22673814

Rebane, Riin; Herodes, Koit

2012-07-01

38

Mitigation of chromatography adsorbent lot performance variability through control of buffer solution design space.  

PubMed

The separation of undesired product-related impurities often poses a challenge in the purification of protein therapeutic species. Product-related impurity species, which may consist of undesirable isoforms, aggregated, or misfolded variants of the desired monomeric form of the product, can be challenging to remove using preparatory scale chromatographic techniques. When using anion exchange chromatography to remove undesirable product-related impurities, the separation can be highly sensitive to relatively small changes in the chromatography operating conditions, including changes to buffer solution pH, buffer solution conductivity protein loading, and operating temperature. When performing difficult separations, slight changes to the chemical and physical properties of the anion exchange adsorbent lot may also impact the separation profile. Such lot-to-lot variability may not be readily measurable by the adsorbent manufacturer, since variability can be highly dependent on a specific protein separation. Consequently, manufacturers of chromatographic adsorbents may not be able to control adsorbent lot to lot variability tightly enough to prevent differences from occurring when performing difficult product-related separations at the preparatory scale. In such cases, it is desirable to design a chromatography step with a control strategy which accounts for adsorbent lot to lot variability in the separation performance. In order to avoid the undesired changes to process consistency and product quality, a proper adjustment of the column operating conditions can be implemented, based on the performance of each adsorbent lot or lot mixture. In this work, we describe how the adjustment of the column buffer solution composition can be used as a design space based-control strategy used to ensure consistent process performance and product quality are achieved for an anion exchange chromatography step susceptible to adsorbent lot to lot performance variability. In addition, a "use test" is described that can be employed to determine the optimal buffer solution compositions for different anion exchange adsorbent lots based on the retention volume of the therapeutic protein during a gradient elution. PMID:24169043

Aono, Hiromasa; Iliescu, Ionela; Cecchini, Doug; Wood, Susanne; McCue, Justin T

2013-11-29

39

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

Microsoft Academic Search

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

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

1997-01-01

40

Masking effect of copper during anisotropic etching of silicon in buffered hydrofluoric acid solutions  

NASA Astrophysics Data System (ADS)

The etching characteristics of silicon samples of (100) orientation in buffered hydrofluoric acid (BHF) solutions containing different levels of dissolved copper were studied systematically using atomic force microscopy, total reflection x-ray fluorescence, inductively coupled plasma mass spectroscopy and transmission electron microscopy techniques. It was found that the presence of trace amounts of copper ions in BHF solutions can cause not only metallic contamination but also very severe surface roughness. Copper deposits onto the silicon surfaces in the form of submonoatomic layer clusters which act as masks during silicon anisotropic etching in BHF solutions. Surface roughness as high as 12 nm was generated in 30 min of etching in buffered hydrofluoric acid solution containing 100 ppb Cu2+. Cross-sectional TEM micrographs showed that silicon was etched anisotropically in BHF solutions containing Cu2+ ions. Etching rates as high as 1.0 nm/min were obtained on the (100) planes of p-type silicon in the presence of a 100 ppb Cu2+. The size of the etching structures depends on the Cu2+ concentration in solution and the etching time.

Li, Guangming; Jiao, Jun; Seraphin, Supapan; Raghavan, Srini; Jeon, Joong S.

1999-02-01

41

Chemical Behaviour of Zirconium Oxychloride Octahydrate and Acetic Acid in Precursor Solution for Zirconia Film Formation on Glass  

Microsoft Academic Search

Precursor solutions for zirconia films on soda lime silica glass substrate were prepared from zirconium oxychloride octahydrate (ZOO) and acetic acid (HOAC) maintaining the mol ratios, [HOAC]\\/[ZOO] = 2, 4, 6, 8 and 10. A characteristic UV absorption band at ~280 nm in the ~120 h aged precursor solutions was identified for acetate group of the zirconium acetato complexed species.

Sunirmal Jana; K. Biswas

1997-01-01

42

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

43

Aspartate buffer and divalent metal ions affect oxytocin in aqueous solution and protect it from degradation.  

PubMed

Oxytocin is a peptide drug used to induce labor and prevent bleeding after childbirth. Due to its instability, transport and storage of oxytocin formulations under tropical conditions is problematic. In a previous study, we have found that the stability of oxytocin in aspartate buffered formulation is improved by the addition of divalent metal ions (unpublished results). The stabilizing effect of Zn(2+) was by far superior compared to that of Mg(2+). In addition, it was found that stabilization correlated well with the ability of the divalent metal ions to interact with oxytocin in aspartate buffer. Furthermore, LC-MS (MS) measurements indicated that the combination of aspartate buffer and Zn(2+) in particular suppressed intermolecular degradation reactions near the Cys(1,6) disulfide bridge. These results lead to the hypothesis that in aspartate buffer, Zn(2+) changes the conformation of oxytocin in such a way that the Cys(1,6) disulfide bridge is shielded from its environment thereby suppressing intermolecular reactions involving this region of the molecule. To verify this hypothesis, we investigate here the conformation of oxytocin in aspartate buffer in the presence of Mg(2+) or Zn(2+), using 2D NOESY, TOCSY, (1)H-(13)C HSQC and (1)H-(15)N HSQC NMR spectroscopy. Almost all (1)H, (13)C and (15)N resonances of oxytocin could be assigned using HSQC spectroscopy, without the need for (13)C or (15)N enrichment. (1)H-(13)C and (1)H-(15)N HSQC spectra showed that aspartate buffer alone induces minor changes in oxytocin in D2O, with the largest chemical shift changes observed for Cys(1). Zn(2+) causes more extensive changes in oxytocin in aqueous solution than Mg(2+). Our findings suggest that the carboxylate group of aspartate neutralizes the positive charge of the N-terminus of Cys(1), allowing the interactions with Zn(2+) to become more favorable. These interactions may explain the protection of the disulfide bridge against intermolecular reactions that lead to dimerization. PMID:23376504

Avanti, Christina; Oktaviani, Nur Alia; Hinrichs, Wouter L J; Frijlink, Henderik W; Mulder, Frans A A

2013-02-28

44

Highly textured La2Zr2O7 buffer layers for YBCO-coated conductors prepared by chemical solution deposition  

Microsoft Academic Search

Recent results of La2Zr2O7 (LZO) buffer layer development for YBa2Cu3O7-x (YBCO-) coated conductors are presented. The major achievement is the development of a new precursor solution starting from 2,4-pentanedionates of lanthanum and zirconium leading to the formation of highly textured LZO buffer layers at low annealing temperatures. The preparation of the precursor solution using only a carboxylic acid as the

Kerstin Knoth; Ruben Hühne; Steffen Oswald; Ludwig Schultz; Bernhard Holzapfel

2005-01-01

45

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

NASA Astrophysics Data System (ADS)

In this work, water-based precursor solutions suitable for dip-coating of thick La 2Zr 2O 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°. TEM studies illustrated the presence of nanovoids, typical for CSD-LZO films annealed under Ar-5%H 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.

Narayanan, Vyshnavi; Lommens, Petra; De Buysser, Klaartje; Hühne, Ruben; Van Driessche, Isabel

2011-11-01

46

A highly selective and sensitive fluorescent chemosensor for Hg2+ in neutral buffer aqueous solution.  

PubMed

A selective and sensitive fluorescent chemosensor for Hg2+, which was composed of two aminonaphthalimide fluorophores and a receptor of 2,6-bis(aminomethyl)pyridine, was synthesized through the reaction of 2,6-bis(chloromethyl)pyridine and N-[2-(2-hydroxyethoxy)ethyl]-4-piperazino-1,8-naphthalimide. The chemosensor showed an about 17-fold increase in fluorescence quantum yield upon addition of 1 equiv of Hg2+ in neutral buffer aqueous solution, and the other common metal ions did not notably disturb the detection of Hg2+. PMID:14982408

Guo, Xiangfeng; Qian, Xuhong; Jia, Lihua

2004-03-01

47

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

48

A resin-buffered nutrient solution for controlling metal speciation in the algal bottle assay.  

PubMed

Metal speciation in solution is uncontrolled during algal growth in the traditional algal bottle assay. A resin-buffered nutrient solution was developed to overcome this problem and this was applied to test the effect of chloride (Cl?) on cadmium (Cd) uptake. Standard nutrient solution was enriched with 40 mM of either NaNO? or NaCl, and was prepared to contain equal Cd²? but varying dissolved Cd due to the presence of CdCl(n)(2-n) complexes. Both solutions were subsequently used in an algal assay in 100 mL beakers that contained only the solution (designated "-R") or contained the solution together with a cation exchange sulfonate resin (2 g L?¹, designated "+R") as a deposit on the bottom of the beaker. Pseudokirchneriella subcapitata was grown for 72 h (1.4 × 10?-1.4 × 10? cells mL?¹) in stagnant solution and shaken three times a day. Growth was unaffected by the presence of the resin (p>0.05). The Cd concentrations in solution of the -R devices decreased with 50-58% of initial values due to Cd uptake. No such changes were found in the +R devices or in abiotic controls. Cd uptake was unaffected by either NaNO? or NaCl treatment in the +R device, confirming that Cd²? is the preferred Cd species in line with the general concept of metal bioavailability. In contrast, Cd uptake in the -R devices was two-fold larger in the NaCl treatment than in the NaNO? treatment (p<0.001), suggesting that CdCl(n)(2-n) complexes are bioavailable in this traditional set-up. However this bioavailability is partially, but not completely, an apparent one, because of the considerable depletion of solution ¹??Cd in this set-up. Resin-buffered solutions are advocated in the algal bottle assay to control trace metal supply and to better identify the role of metal complexes on bioavailability. PMID:22447105

Verheyen, L; Merckx, R; Smolders, E

2012-06-15

49

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

50

Influence of albumin on the electrochemical behaviour of Zr in phosphate buffered saline solutions.  

PubMed

The corrosion behaviour of Zr in phosphate buffered saline (PBS) solutions with various concentrations (0-4 g L(-1)) of albumin was studied by electrochemical techniques and surface analysis. Addition of albumin to PBS solutions moved the open circuit potential (OCP) to less nobler direction. OCP, polarization resistance and impedance increased and the corrosion current decreased over immersion duration. At early stages of immersion, the resistance was increased with the concentration of albumin because of the high adsorption kinetics of albumin on metal. After the long term immersion, the resistance in PBS without albumin was higher than PBS with albumin owing to the anodic dissolution effect of albumin on metal. According to the analysis of effective capacitances, a normal distribution of time-constants was proposed to estimate the surface film on Zr. A corrosion mechanism of Zr in PBS with different albumin was proposed based on electrochemical analysis. PMID:23180000

Wang, Lu-Ning; Huang, Xian-Qiu; Shinbine, Alyssa; Luo, Jing-Li

2013-02-01

51

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

52

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

53

Thermodynamic characteristics of the interaction between nicotinic acid and phenylalanine in an aqueous buffer solution at 298 K  

NASA Astrophysics Data System (ADS)

The interaction between L-phenylalanine and nicotinic acid is studied by solution calorimetry in an aqueous buffer solution (pH 7.35) at different ratios of the reagents. Experimental data on the enthalpy of dissolution of amino acid in the buffer solution of nicotinic acid at 298.15 K are calculated. The values of thermodynamic parameters for the complexation of L-phenylalanine with nicotinic acid are calculated. It is shown that the formation of a 1: 2 molecular complex is stabilized by the entropy factor due to the dominant role of the dehydration effect of initial reagents.

Badelin, V. G.; Tyunina, E. Yu.; Mezhevoi, I. N.; Tarasova, G. N.

2013-08-01

54

Chemical behaviour of zirconium oxychloride octahydrate and acetic acid in precursor solution for zirconia film formation on glass  

Microsoft Academic Search

Precursor solutions for zirconia films on soda lime silica glass substrate were prepared from zirconium oxychloride octahydrate\\u000a (ZOO) and acetic acid (HOAC) maintaining the mol ratios, [HOAC]\\/[ZOO]=2, 4, 6, 8 and 10. A characteristic UV absorption band\\u000a at ?280 nm in the ?120h aged precursor solutions was identified for acetate group of the zirconium acetato complexed species.\\u000a The presence of

Sunirmal Jana; Prasanta K. Biswas

1997-01-01

55

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

56

Light scattering and membrane formation studies on polysulfone solutions in NMP and in mixed solvents of NMP and ethyl acetate  

Microsoft Academic Search

The relationship between the characteristics of the polymer dope solution and the skin formation mechanism as well as the performance of the asymmetric membrane has been investigated. The solution characteristics have been studied on the polysulfone (PSf) dope solution as a function of the concentrations of both polymer and the cosolvent, ethyl acetate (EA), by dynamic light scattering. An anomalous

Jongok Won; Yong Soo Kang; Hyun Chae Park; Un Young Kim

1998-01-01

57

Labile synthetic cadmium complexes are not bioavailable to Pseudokirchneriella subcapitata in resin buffered solutions.  

PubMed

The Free Ion Activity Model (FIAM) predicts that cadmium (Cd) uptake by organisms is identical for solutions with the same free Cd(2+) concentration and inorganic composition. Clear exceptions to the FIAM have been shown for Cd uptake by plant roots, periphyton and human cells where labile Cd complexes increase bioavailability and which has been attributed to their role in enhancing Cd diffusion towards the uptake cells. Here, we assessed the role of labile Cd complexes on Cd uptake by algae, for which diffusion limitations should be less pronounced due to their smaller size. Long-term (3 days) Cd uptake by the green algae Pseudokirchneriella subcapitata was measured in resin buffered solutions with or without synthetic ligands and at three Cd(2+) ion activities (pCd 8.2-5.7). The free Cd(2+) activity was maintained during the test using a metal-selective resin located in the algal bottles. Total dissolved Cd increased up to 35-fold by adding the synthetic ligands at constant Cd(2+) activity. In contrast, Cd uptake by algae increased maximally 2.8 fold with increasing concentration of the synthetic ligands and the availability of the complexes were maximally 5.2% relative to Cd(2+) for NTA and CDTA complexes. It is concluded that labile Cd complexes do not greatly enhance Cd bioavailability to the unicellular algae and calculations suggest that Cd transport from solution to these small cells is not rate limiting. PMID:22903064

Verheyen, L; Merckx, R; Smolders, E

2012-11-15

58

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

59

BIOKID: Randomized controlled trial comparing bicarbonate and lactate buffer in biocompatible peritoneal dialysis solutions in children [ISRCTN81137991  

PubMed Central

Background Peritoneal dialysis (PD) is the preferred dialysis modality in children. Its major drawback is the limited technique survival due to infections and progressive ultrafiltration failure. Conventional PD solutions exert marked acute and chronic toxicity to local tissues. Prolonged exposure is associated with severe histopathological alterations including vasculopathy, neoangiogenesis, submesothelial fibrosis and a gradual loss of the mesothelial cell layer. Recently, more biocompatible PD solutions containing reduced amounts of toxic glucose degradation products (GDPs) and buffered at neutral pH have been introduced into clinical practice. These solutions contain lactate, bicarbonate or a combination of both as buffer substance. Increasing evidence from clinical trials in adults and children suggests that the new PD fluids may allow for better long-term preservation of peritoneal morphology and function. However, the relative importance of the buffer in neutral-pH, low-GDP fluids is still unclear. In vitro, lactate is cytotoxic and vasoactive at the concentrations used in PD fluids. The BIOKID trial is designed to clarify the clinical significance of the buffer choice in biocompatible PD fluids. Methods/design The objective of the study is to test the hypothesis that bicarbonate based PD solutions may allow for a better preservation of peritoneal transport characteristics in children than solutions containing lactate buffer. Secondary objectives are to assess any impact of the buffer system on acid-base status, peritoneal tissue integrity and the incidence and severity of peritonitis. After a run-in period of 2 months during which a targeted cohort of 60 patients is treated with a conventional, lactate buffered, acidic, GDP containing PD fluid, patients will be stratified according to residual renal function and type of phosphate binding medication and randomized to receive either the lactate-containing Balance solution or the bicarbonate-buffered Bicavera® solution for a period of 10 months. Patients will be monitored by monthly physical and laboratory examinations. Peritoneal equilibration tests, 24-h dialysate and urine collections will be performed 4 times. Peritoneal biopsies will be obtained on occasion of intraabdominal surgery. Changes in small solute transport rates, markers of peritoneal tissue turnover in the effluent, acid-base status and peritonitis rates and severity will be analyzed. PMID:15485574

Nau, Barbara; Schmitt, Claus P; Almeida, Margarida; Arbeiter, Klaus; Ardissino, Gianluigi; Bonzel, Klaus E; Edefonti, Alberto; Fischbach, Michel; Haluany, Karin; Misselwitz, Joachim; Kemper, Markus J; Ronnholm, Kai; Wygoda, Simone; Schaefer, Franz

2004-01-01

60

Neutron dosimetry in boron neutron capture therapy using aqueous solutions of lithium acetate  

NASA Astrophysics Data System (ADS)

This paper presents the development of a dosimetry method, based on liquid scintillation (LS) counting of the tritium that is produced in aqueous solutions of lithium acetate, for the determination of the boron and nitrogen absorbed doses in-phantom in BNCT. The dosimeter is passive, integrating, approximately tissue equivalent, and insensitive to gamma rays and the elastic scattering of fast neutrons. The dosimetry method exhibits a response which is proportional to the boron and nitrogen absorbed doses and which can be calibrated to NIST standard solutions of water spiked with tritium. For 0.2 g of lithium acetate dissolved in a milliliter of water, the measured sensitivity is (1.73±0.04)×10 -9 cpm per unit of thermal neutron fluence (in neutrons/cm 2). For the LS analyzer that was used, the background signal was 12.84±0.02 cpm, yielding a thermal neutron fluence threshold for this detection method of approximately 7×10 9 neutrons/cm 2.

Rakovan, L. J.; Blue, T. E.; Vest, A. L.

61

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

E-print Network

Films in Buffered pH Solutions Y. Lin1 , J.J. Vlassak1 , T.Y. Tsui2 , and A.J. McKerrow2 1 DEAS, Harvard and barrier thin films in buffered solutions of different pH value is of both technical and scientific (OSG) films in pH buffer solutions was studied in this work. Crack path and subcritical fracture

62

Gender-dependent metabolic remodeling during heart preservation in cardioplegic celsior and histidine buffer solution.  

PubMed

Understanding heart metabolism during preservation is crucial to develop new effective cardioplegic solutions. We aim to investigate metabolic alterations during heart preservation in the clinically used Celsior (Cs) and histidine buffer solution (HBS). We also focused in gender-specific metabolic adaptations during ischemia. We followed energy metabolism in hearts from males and females preserved during 6 hours in Cs and HBS. Hearts were subjected to cold ischemia (4°C) in Cs or HBS, and aliquots of the cardioplegic solution were collected throughout preservation for nuclear magnetic resonance analysis. HBS-preserved hearts from males consumed glucose mostly between 240 and 360 minutes, whereas HBS-preserved hearts from females consumed glucose throughout the 6 hours of ischemia. Lactate production rates followed approximately the glucose consumption rates in HBS-preserved hearts. The lactate to alanine ratio, an indicator of the redox state, was increased in HBS-preserved hearts when compared with Cs-preserved hearts. Hearts from males presented a higher redox state than those from females preserved in Cs after 300 minutes. Both Cs and HBS were capable of preventing acidification in hearts from females but not in hearts from males, which decreased the extracellular pH. HBS-preserved hearts from males and females produced 0.1 ± 0.01 and 0.15 ± 0.03 ?mol·min·gdw of lactate, respectively. Those rates were significantly higher than in Cs-preserved hearts. Thus, Cs was more effective in preventing lactate production. We conclude that glycolysis and lactate production are stimulated in HBS-preserved hearts. HBS shows better overall results particularly in hearts from females, which presented less extracellular acidification and were more effective in recycling the metabolic subproducts. PMID:22892386

Alves, Marco G; Oliveira, Pedro F; Martins, Fátima O; Oliveira, Paulo J; Carvalho, Rui A

2012-08-01

63

RAD: A Compile-Time Solution to Buffer Overflow Attacks Tzi-cker Chiueh Fu-Hau Hsu  

E-print Network

to attack programs since the 1960s [18]. The most famous BO attack is the Internet Worm written by Robert TRAD: A Compile-Time Solution to Buffer Overflow Attacks Tzi-cker Chiueh Fu-Hau Hsu Computer Science attack can inflict upon almost arbitrary programs and is one of the most common vulnerabilities that can

Chiueh, Tzi-cker

64

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

65

YBCO films buffered by pyrochlore Nd 2Mo 2O 7 layer on YSZ substrates by chemical solution deposition  

Microsoft Academic Search

A chemical solution deposition process was used to grow epitaxial Nd2Mo2O7 (NMO) buffer layers on YSZ substrates to produce YBa2Cu3O7?? (YBCO) coated conductors. The NMO precursor solution prepared using metal acetylacetonates was spin-coated onto single crystal YSZ substrate of 10mm×10mm in size at 3000rpm for 30s and heat-treated at 1000°C for 2h in Ar after calcinated at 550°C for 1h.

Weibo Yang; Guofang Zhang; Lihua Jin; Chengshan Li; Guo Yan; Yafeng Lu

2009-01-01

66

The formation of stable pH gradients with weak monovalent buffers for isoelectric focusing in free solution  

NASA Technical Reports Server (NTRS)

Two methods which utilize simple buffers for the generation of stable pH gradients (useful for preparative isoelectric focusing) are compared and contrasted. The first employs preformed gradients comprised of two simple buffers in density-stabilized free solution. The second method utilizes neutral membranes to isolate electrolyte reservoirs of constant composition from the separation column. It is shown by computer simulation that steady-state gradients can be formed at any pH range with any number of components in such a system.

Mosher, Richard A.; Thormann, Wolfgang; Graham, Aly; Bier, Milan

1985-01-01

67

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

68

Influence of cellulose on ion diffusivity in 1-ethyl-3-methyl-imidazolium acetate cellulose solutions.  

PubMed

Solutions of microcrystalline cellulose in 1-ethyl-3-methyl-imidazolium acetate have been investigated using pulsed-field gradient (1)H NMR. In all cases the geometrically larger cation was found to diffuse faster than the smaller anion. Arrhenius temperature analysis has been applied to the ion diffusivities giving activation energies. The diffusion and published viscosity data for these solutions were shown to follow the Stokes-Einstein relationship, giving hydrodynamic radii of 1.6 Å (cation) and 1.8 Å (anion). Theories for obstruction, free-volume and hydrodynamic effects on solvent diffusion have been applied. The Mackie-Meares and Maxwell-Fricke obstruction models provided a correct trend only when assuming a certain fraction of ions are bound to the polymer. From this fraction it was shown that the maximum dissolvable cellulose concentration is ?27% w/w, which is consistent with the highest known prepared concentration of cellulose in this ionic liquid. The Phillies' hydrodynamic model is found to give the best description for the cellulose concentration dependence of the ion diffusivities. PMID:20923202

Lovell, Christopher S; Walker, Adam; Damion, Robin A; Radhi, Asanah; Tanner, Steven F; Budtova, Tatiana; Ries, Michael E

2010-11-01

69

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

Microsoft Academic Search

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

Qun-jie Xu; Guo-ding Zhou

2008-01-01

70

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

71

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

72

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

E-print Network

Experimental studies were conducted using albite sand (250- 500 mm) with distilled water, 0.07m acetate, and 0.07m acetate+0.005m citrate solutions in a hydrothermal flow-through system at conditions that simulate diagenesis. Pore-fluid chemistry...

Carpenter, Thomas Doyle

2012-06-07

73

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

74

Recovery of acetic acid from dilute aqueous solutions using catalytic dehydrative esterification with ethanol.  

PubMed

We have developed a direct esterification of aqueous acetic acid with ethanol (molar ratio=1:1) catalyzed by polystyrene-supported or homogeneous sulfonic acids toward the recovery of acetic acid from wastewater in chemical plants. The equilibrium yield was significantly increased by the addition of toluene, which had a high ability to extract ethyl acetate from the aqueous phase. It was shown that low-loading and alkylated polystyrene-supported sulfonic acid efficiently accelerated the reaction. These results suggest that the construction of hydrophobic reaction environments in water was critical in improving the chemical yield. Addition of inorganic salts was also effective for the reaction under not only biphasic conditions (toluene-water) but also toluene-free conditions, because the mutual solubility of ethyl acetate and water was suppressed by the salting-out effect. Among the tested salts, CaCl(2) was found to be the most suitable for this reaction system. PMID:23290939

Yagyu, Daisuke; Ohishi, Tetsuo; Igarashi, Takeshi; Okumura, Yoshikuni; Nakajo, Tetsuo; Mori, Yuichiro; Kobayashi, Sh?

2013-03-01

75

Transport of solutes through calix[4]pyrrole-containing cellulose acetate films  

Microsoft Academic Search

Films of cellulose acetate containing different concentrations of meso-octamethyl-porphyrinogen (calix[4]pyrrole) were prepared and characterized using UV–vis and FTIR spectroscopy, DSC and SEM. Incorporation of calix[4]pyrrole into cellulose acetate leads to a decrease in the degree of hydrophilicity of the polymeric matrix. However, a slight increase in the percentage of water uptake of the polymer is found with an increase of

A. J. M. Valente; A. Jiménez; A. C. Simões; H. D. Burrows; A. Ya. Polishchuk; V. M. M. Lobo

2007-01-01

76

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

PubMed

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

Wu, Wenbiao; Yang, Yixing

2011-01-01

77

Spray pyrolytic synthesis of large area NiO x thin films from aqueous nickel acetate solutions  

Microsoft Academic Search

Non-stoichiometric nickel oxide thin films were prepared by pyrolytic decomposition of aerosol droplets of aqueous nickel acetate solution. Conventional un-nebulized spray pyrolysis system was used for the synthesis of thin films. The fine droplets were atomized by employing compressed air as carrier gas and allowed to decompose onto pre-heated Sn doped In2O3 (ITO) coated glass. The preparative parameters such as

J. D. Desai; Sun-Ki Min; Kwang-Deog Jung; Oh-Shim Joo

2006-01-01

78

Coagulation of chitin and cellulose from 1-ethyl-3-methylimidazolium acetate ionic-liquid solutions using carbon dioxide.  

PubMed

Chemisorption of carbon dioxide by 1-ethyl-3-methylimidazolium acetate ([C2 mim][OAc]) provides a route to coagulate chitin and cellulose from [C2 mim][OAc] solutions without the use of high-boiling antisolvents (e.g., water or ethanol). The use of CO2 chemisorption as an alternative coagulating process has the potential to provide an economical and energy-efficient method for recycling the ionic liquid. PMID:24115399

Barber, Patrick S; Griggs, Chris S; Gurau, Gabriela; Liu, Zhen; Li, Shan; Li, Zengxi; Lu, Xingmei; Zhang, Suojiang; Rogers, Robin D

2013-11-18

79

Antibacterial and photocatalytic activity of TiO2 and ZnO nanomaterials in phosphate buffer and saline solution.  

PubMed

We studied antibacterial and photocatalytic activity of anatase TiO2 and ZnO in phosphate buffer and saline solution. We found that the different anions in the suspension medium (chloride and phosphate) significantly affected the following suspension properties: the stability of nanoparticle suspension, the release of metal ions from the nanoparticles, and the production of the reactive oxygen species by the nanoparticles. As a result, antibacterial activity and photocatalytic dye degradation were also affected. However, the effect of the suspension medium was different for ZnO and TiO2. Obtained results are discussed. PMID:23661082

Ng, Alan Man Ching; Chan, Charis May Ngor; Guo, Mu Yao; Leung, Yu Hang; Djuriši?, Aleksandra B; Hu, Xu; Chan, Wai Kin; Leung, Frederick Chi Chung; Tong, Shuk Yin

2013-06-01

80

Preformulation studies for an ultrashort-acting neuromuscular blocking agent GW280430A. I. Buffer and cosolvent effects on the solution stability.  

PubMed

GW280430A is an ultrashort-acting neuromuscular blocking agent targeted at muscle relaxation to facilitate surgical intubation. The objective of this work was to study the buffer and cosolvent effects on the solution stability of GW280430A. The buffer catalytic effect was examined in citrate, malate, tartrate, and glycine by measuring the rate of degradation of GW280430A (0.2 mg/mL) at constant pH (3), ionic strength (0.15 M), and various buffer concentrations (0.01-0.05 M). The temperature dependence of the buffer catalytic effect and the degradation of the GW280430A in cosolvent (ethanol, propylene glycol, polyethylene glycol 400, N,N-dimethylacetamide)/water mixtures were studied at 40, 50, and 60 degrees C. The loss of parent drug was monitored by reverse-phase high-performance liquid chromatography. The degradation of GW280430A followed first-order kinetics in all buffer solutions. Significant buffer-catalyzed hydrolysis of GW280430A was observed with citrate, tartrate, and malate buffers, but not in glycine-buffered solutions. The activation energies in all buffered drug solutions ranged from 70 to 80 kJ/mol and decreased with increasing buffer concentration. GW280430A degradation was primarily through ester hydrolysis and followed first-order kinetics in aqueous solutions. In cosolvent/water mixtures, new degradation products were observed, indicating a chemical reaction between GW280430A and cosolvents. The reaction activation energies in the cosolvent/water mixtures ranged from 75 to 85 kJ/mol, with the longest t(0.9) at 5 degrees C equal to approximately 12 months and at 25 degrees C equal to 36 days. Consideration should be given to the incorporation of glycine or a low concentration of citrate, malate, or tartrate buffer in the parenteral formulation development of GW280430A. Cosolvents prolonged the predicted t(0.9) for GW280430A in solution, but the enhancement was not significant enough to pursue a liquidformulation. PMID:11926357

Zhu, Haijian; Meserve, Kathy; Floyd, Alison

2002-01-01

81

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

PubMed

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

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

2001-12-01

82

Determination of the Glass Electrode Parameters by Means of Potentiometric Titration of Acetic Acid in Aqueous Sodium or Potassium Chloride Solutions at 25°C  

Microsoft Academic Search

Single-ion activity coefficient equations are presented for the calculation of stoichiometric (molality scale) dissociation constants Km for acetic acid in aqueous NaCl or KCl solutions at 25°C. These equations are of the Pitzer or Hückel type and apply to the case where the inert electrolyte alone determines the ionic strength of the acetic acid solution considered. Km for a certain

Jaakko I. Partanen; Pekka M. Juusola; Pentti O. Minkkinen

1999-01-01

83

Changes in the structure of water in aqueous solutions of acetic acid, depending on concentration and temperature according to densitometry, viscosimetry, and IR spectroscopy data  

NASA Astrophysics Data System (ADS)

The structural features of aqueous solutions of acetic acid are studied by means of viscosimetry, densimetry, and IR spectroscopy within the temperature range of 283.15-333.15 K and a concentration range of 0-80%. The results from our experiments are used to calculate the parameters of viscous flow activation, the structural temperature, the partial molar volume of acetic acid in the solution, the thermal expansion coefficient, and the energies and lengths of the hydrogen bonds between water molecules. The concentration dependences of these parameters are analyzed. Based on the obtained results, we conclude that acetic acid disrupts the structure of water.

Masimov, E. A.; Khasanov, G. Sh.; Pashaev, B. G.

2013-06-01

84

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

85

Fluorescence quenching of etilefrine by acetate anion  

NASA Astrophysics Data System (ADS)

Acid dissociation in the excited state of antihypotensor drug etilefrine [2-(ethylamino1-3-hydroxyphenyl)ethanol] is studied. Fluorescence of etilefrine decreases at pH<7 and is related to phenolic group dissociation. However, intensity of etilefrine fluorescence diminishes as the concentration of the acetate anion increases at pH>7. Analyses of the absorption and fluorescence spectra of aqueous solutions of etilefrine in the presence of acetate anions have been made. Considering the existence of an equilibrium in the excited state the values of 3.47×10 -9 and 0.216×10 -9 M -1 s -1 have been obtained for the rate constants for direct and inverse reactions, respectively. Moreover, the lifetime ( ?0'=0.58×10 -9 s) and quantum yield (0.01) of non-protonated etilefrine have been determined. Our results seem to support the existence of a dynamic quenching process based on a proton transfer mechanism induced by acetate anions. This process could represent a serious inconvenience in analytical fluorimetric techniques taking into account that the acetic acid/acetate pair is commonly used as a buffer. Additional fluorescence quenching by H + ions could be involved in acid aqueous mediums. At high concentrations of acetic acid, a value of 2.98×10 -9 M -1 s -1 for the bimolecular constant for the quenching by H + has been calculated.

Quintero Osso, B.; Carazo Rodríguez, F. M.; Morales Domingo, J. J.; Cabeza González, M. C.; Thomas Gómez, J.

1999-02-01

86

Experimental study of gold-hydrosulphide complexing in aqueous solutions at 350–500°C, 500 and 1000 bars using mineral buffers  

Microsoft Academic Search

The solubility of gold was measured in KCl solutions (0.001–0.1 m) at near-neutral to weakly acidic pH in the presence of the K-feldspar-muscovite-quartz, andalusite-muscovite-quartz, and pyrite-pyrrhotite-magnetite buffers at temperatures 350 to 500°C and pressures 0.5 and 1 kbar. These mineral buffers were used to simultaneously constrain pH, f(S2), and f(H2). The experiments were performed using a CORETEST flexible Ti-cell rocking

Boris R. Tagirov; Stefano Salvi; Jacques Schott; Nina N. Baranova

2005-01-01

87

Aspirin absorption rates and platelet inhibition times with 325-mg buffered aspirin tablets (chewed or swallowed intact) and with buffered aspirin solution  

Microsoft Academic Search

Large clinical trials such as the second International Study of Infarct Survival routinely gave patients with myocardial infarction a chewed aspirin, yet there are no data to show whether chewing of aspirin is better, or worse, than swallowing a whole tablet. We performed a randomized, placebo-controlled study to determine whether chewing aspirin or administering it in solution accelerates its absorption

Mark Feldman; Byron Cryer

1999-01-01

88

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

PubMed

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 pathogens on skin during refrigerated storage. In experiment 1, raw chicken skin samples were dipped into a suspension of either 10(8) cfu/mL of Salmonella Typhimurium, Escherichia coli O157:H7, or Listeria monocytogenes for 30 s and then immersed in PBS or an OA wash solution mixture of 0.8% citric, 0.8% acetic, and 0.8% propionic acid (at equal wt/vol concentrations) for an additional 30 s. In experiment 2, three different concentrations of the OA wash solution (0.2, 0.4, and 0.6% at equal wt/vol concentrations) were tested against chicken skin samples contaminated with Salmonella Typhimurium. Viable pathogenic bacteria on each skin sample were enumerated after 1 and 24 h of storage at 4°C in both experiments. In experiment 3, skin samples were initially treated on d 1 with PBS or 2 concentrations of the OA mixture (0.4 and 0.8%), and total aerobic bacteria were enumerated during a 2-wk storage period. In all experiments, significant (P < 0.05) differences were observed when skin samples were treated with the OA wash solution and no spoilage organisms were recovered at any given time point, whereas increasing log10 numbers of spoilage organisms were recovered over time in PBS-treated skin samples. These results suggest that 0.2 to 0.8% concentrations of an equal-percentage mixture of this OA combination may reduce pathogens and spoilage organisms and improve food safety properties of raw poultry. PMID:23873572

Menconi, A; Shivaramaiah, S; Huff, G R; Prado, O; Morales, J E; Pumford, N R; Morgan, M; Wolfenden, A; Bielke, L R; Hargis, B M; Tellez, G

2013-08-01

89

Fabrication of ZnO Thin-Film Transistors by Chemical Vapor Deposition Method using Zinc Acetate Solution  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin-film transistors (TFTs) were fabricated by thermal chemical vapor deposition (CVD) using aqueous solutions of zinc acetate (ZnAc2) dihydrate as a source. The precursor was supplied to the substrate by the nitrogen bubbling method through a plate with numerous orifices in the ZnAc2 solution. The ZnO thin films were grown on silicon substrates in the growth temperature (TG) range from 280 to 700 °C. The growth rate of ZnO thin films were linearly proportional to the growth temperature, which suggested that the growth rate is limited by the decomposition of ZnAc2. Depletion-mode TFTs with the ZnO film grown at TG = 350 °C was found to exhibit a relatively low saturation mobility (µsat). However, µsat increased from 1 to 14 cm2·V-1·s-1 and the operational mode was changed from the depletion mode to the enhancement mode by annealing treatment at 200 °C for 2 h under N2 ambient.

Alias, Afishah; Hazawa, Kouta; Kawashima, Nobuaki; Fukuda, Hisashi; Uesugi, Katsuhiro

2011-01-01

90

Differences in proton-coupled electron-transfer reactions of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) between buffered and unbuffered aqueous solutions.  

PubMed

The electrochemical reduction mechanisms of flavin mononucleotide (FMN) in buffered aqueous solutions at pH 3-11 and unbuffered aqueous solutions at pH 2-11 were examined in detail using variable-scan-rate cyclic voltammetry (? = 0.1-20 V s(-1)), controlled-potential bulk electrolysis, UV-vis spectroscopy, and rotating-disk-electrode voltammetry. In buffered solutions at pH 3-5, FMN undergoes a two-electron/two-proton (2e(-)/2H(+)) reduction to form FMNH2 at all scan rates. When the buffered pH is increased to 7-9, FMN undergoes a 2e(-) reduction to form FMN(2-), which initially undergoes hydrogen bonding with water molecules, followed by protonation to form FMNH(-). At a low voltammetric scan rate of 0.1 V s(-1), the protonation reaction has sufficient time to take place. However, at a higher scan rate of 20 V s(-1), the proton-transfer reaction is outrun, and upon reversal of the scan direction, less of the FMNH(-) is available for oxidation, causing its oxidation peak to decrease in magnitude. In unbuffered aqueous solutions, three major voltammetric waves were observed in different pH ranges. At low pH in unbuffered solutions, where [H(+)] ? [FMN], (FMN)H(-) undergoes a 2e(-)/2H(+) reduction to form (FMNH2)H(-) (wave 1), similar to the mechanism in buffered aqueous solutions at low pH. At midrange pH values (unbuffered), where pH ? pKa of the phosphate group and [FMN] ? [H(+)], (FMN)H(-) undergoes a 2e(-) reduction to form (FMN(2-))H(-) (wave 2), similar to the mechanism in buffered aqueous solutions at high pH. At high pH (unbuffered), where pH ? pKa = 6.2 of the phosphate group, the phosphate group loses its second proton to be fully deprotonated, forming (FMN)(2-), and this species undergoes a 2e(-) reduction to form (FMN(2-))(2-) (wave 3). PMID:24079606

Tan, Serena L J; Kan, Jia Min; Webster, Richard D

2013-11-01

91

Wire segmenting for improved buffer insertion  

Microsoft Academic Search

Buffer insertion seeks to place buffers on the wires of a signal netto minimize delay. Van Ginneken [Buffer Placement in Distributed RC-tree Networks for Minimal Elmore Delay] proposed an optimal dynamicprogramming solution (with extensions proposed by [7] [8][9] [12]) such that at most one buffer can be placed on a singlewire. This constraint can hurt solution quality, but it may

Charles J. Alpert; Anirudh Devgan

1997-01-01

92

Efficiency of buffered aqueous carboxylic acid solutions and organic solvents to absorb SOâ from industrial flue gas; solubility data from gas-liquid chromatography  

Microsoft Academic Search

Nine adsorbents were examined. These potential candidates for flue gas desulfurization included 1-methyl-2-pyrrolidinone, tri-n-butyl phosphate (TBP), both 0.5 M and 1.0 M solutions of citric acid and glycolic acid, buffered to pH's of 4.5 and 3.8, and pure water. Infinite dilution activity coefficients of SOâ were obtained by gas-liquid chromatography in a trial solvent of Nitrobenzene, and then in systems

Sanza

1982-01-01

93

Detailed investigations on La 2Zr 2O 7 buffer layers for YBCO-coated conductors prepared by chemical solution deposition  

Microsoft Academic Search

An extensive study of the growth and properties of La2Zr2O7 (LZO) buffer layers prepared by chemical solution deposition on Ni–5at.%W rolling-assisted biaxially textured substrates, which is presently of great interest for the preparation of YBa2Cu3O7?x-coated conductors, is presented. The main focus was on the understanding of the decomposition of the precursor layers, and their growth and texture formation, as well

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

2007-01-01

94

Multistate outbreak of fungal infection associated with injection of methylprednisolone acetate solution from a single compounding pharmacy - United States, 2012.  

PubMed

On September 18, 2012, the Tennessee Department of Health was alerted by a clinician regarding a patient with culture-confirmed Aspergillus fumigatus meningitis diagnosed 46 days after epidural steroid injection at a Tennessee ambulatory surgical center. By September 27, the initial investigation, carried out by the Tennessee Department of Health in collaboration with CDC and the North Carolina Department of Health and Human Services, had identified an additional eight patients with clinically diagnosed, culture-negative meningitis: seven in Tennessee and one in North Carolina. All nine patients had received epidural steroid injection with preservative-free methylprednisolone acetate solution (MPA), compounded at New England Compounding Center (NECC) in Framingham, Massachusetts. All nine patients had received one or more injections from three lots of MPA (lot numbers 05212012@68; 06292012@26; and 08102012@51). As of October 10, a multistate investigation led by CDC in collaboration with state and local health departments and the Food and Drug Administration (FDA) had identified 137 cases and 12 deaths associated with this outbreak in 10 states. Active case-finding efforts and extensive investigation into medications and medication lot numbers received by patients have confirmed that, as of October 10, no cases were associated with other lots of MPA, nor were any associated with other NECC products. This report describes the ongoing investigation by CDC and state and local health departments, and includes important recommendations for physicians and patients. PMID:23076093

2012-10-19

95

[3H]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 Central

[3H]Adenine has previously been used to label the newly discovered G protein-coupled murine adenine receptors. Recent reports have questioned the suitability of [3H]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 [3H]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°C for some time may contain bacterial contaminations that exhibit high affinity binding for [3H]adenine. Specific binding is abolished by heating the contaminated buffer or filtering it through 0.2-?m 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 [3H]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 [3H]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; Brussel, Hannelore

2007-01-01

96

Effect of Time and Degree of Saturation of Buffer Solutions on Artificial Carious Lesion Formation in Human Tooth Enamel  

Microsoft Academic Search

The chemical systems to produce carious lesions described in the literature can be divided into three types: (a) gel systems, (b) systems containing a substance which decreases the dissolution rate of the mineral in the surface area of tooth enamel and (c) buffer systems containing calcium and phosphate. The third system can give essential information in the physicochemical sense, if

H. M. Theuns; J. W. E. van Dijk; F. C. M. Driessens; A. Groeneveld

1983-01-01

97

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

PubMed

Water and the organic solvents tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1-propanol, 2-propanol, tert-butanol, acetonitrile, or acetone are completely miscible in all proportions at room temperature. Here, we present new buffering-out phase separation systems that the above mentioned organic aqueous solutions can be induced to form two liquid phases in the presence of a biological buffer 2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid (TES). The lower liquid phase is rich in water and buffer, and the upper phase is organic rich. This observation has both practical and mechanistic interests. The phase diagrams of these systems were constructed by experimental measurements at ambient conditions. Molecular dynamic (MD) simulations were performed for TES + water + THF system to understand the interactions between TES, water, and organic solvent at molecular level. Several composition-sets for this system, beyond and inside the liquid-liquid phase-splitting region, have been simulated. Interestingly, the MD simulation for compositions inside the phase separation region showed that THF molecules are forced out from the water network to start forming a new liquid phase. The hydrogen-bonds, hydrogen-bonds lifetimes, hydrogen-bond energies, radial distribution functions, coordination numbers, the electrostatic interactions, and the van der Waals interactions between the different pairs have been calculated. Additionally, MD simulations for TES + water + tert-butanol?acetonitrile?acetone phase separation systems were simulated. The results from MD simulations provide an explanation for the buffering-out phenomena observed in [TES + water + organic solvent] systems by a mechanism controlled by the competitive interactions of the buffer and the organic solvent with water. The molecular mechanism reported here is helpful for designing new benign separation materials. PMID:23822250

Taha, Mohamed; Lee, Ming-Jer

2013-06-28

98

Experimental determination of the complexation of strontium and cesium with acetate in high-temperature aqueous solutions  

Microsoft Academic Search

Radionuclides are present in contaminated surfacial waters, but their behavior in the presence of natural organic acids is poorly known. Dissociation constants for the strontium acetate (SrCH3COO+) and cesium acetate (CsCH3COO0) ion pair were determined by potentiometry at temperatures from 25 to 175°C at the saturation pressure of water. Logarithms of measured dissociation constants (log K) decrease with increasing temperature,

K. Vala Ragnarsdottir; Patricia Fournier; Eric H. Oelkers; Jean-Claude Harrichoury

2001-01-01

99

Densities and excess molar volumes of formic acid, acetic acid and propionic acid in pure water and in water?+?Surf Excel solutions at different temperatures  

Microsoft Academic Search

Densities, ? of the systems formic acid, acetic acid and propionic acid in water and in 0.05% and 0.1% Surf Excel (SE) solutions in water were measured at temperatures 303.15, 308.15, 313.15, 318.15 and 323.15?K respectively covering the whole composition range. Excess molar volumes, for the systems were found to be negative and their values were found to increase with

M. A. Motin; M. H. Kabir; E. M. Huque

2005-01-01

100

Liquid-liquid extraction of ethanol from aqueous solutions with amyl acetate, benzyl alcohol, and methyl isobutyl ketone at 298. 15. Kappa  

Microsoft Academic Search

Experimental mutual solubility and tie-line data were determined for three ternary liquid-liquid systems containing water, ethanol, and amyl acetate, benzyl alcohol, and methyl isobutyl ketone at 298.15Î in order to obtain their complete phase diagrams and to determine which is the most suitable solvent for extraction of ethanol from aqueous solutions. Tie lines were determined correlating the density of the

Horacio N. Solimo; Hector E. Martinez; Roque Riggio

1989-01-01

101

Crystal structures of TiO2 thin coatings prepared from the alkoxide solution via the dip-coating technique affecting the photocatalytic decomposition of aqueous acetic acid  

Microsoft Academic Search

TiO2 coatings with different crystal structures were prepared from alkoxide solutions via the dip-coating technique. The physical properties, except the crystal structure, were adjusted to distinguish the effect of crystal structure on their photocatalytic property. The results of photocatalytic measurements using TiO2 coatings with different crystal structures showed that the decomposition of aqueous acetic acid was enhanced by the content

K. Kato; A. Tsuzuki; H. Taoda; Y. Torii; T. Kato; Y. Butsugan

1994-01-01

102

Liquid-liquid extraction of ethanol from aqueous solutions with amyl acetate, benzyl alcohol, and methyl isobutyl ketone at 298. 15. Kappa  

SciTech Connect

Experimental mutual solubility and tie-line data were determined for three ternary liquid-liquid systems containing water, ethanol, and amyl acetate, benzyl alcohol, and methyl isobutyl ketone at 298.15{Kappa} in order to obtain their complete phase diagrams and to determine which is the most suitable solvent for extraction of ethanol from aqueous solutions. Tie lines were determined correlating the density of the binodal curve as a function of composition and the plait points using the Othmer and Tobias method. The experimental data were also correlated with the UNIFAC group contribution method. A qualitative agreement was obtained. Experimental results show that amyl acetate is a better solvent than methyl isobutyl ketone and benzyl alcohol.

Solimo, H.N. (Instituto de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman, 4000 San Miguel de Tucuman (AR)); Martinez, H.E.; Riggio, R. (Facultad de Ciencias Naturales, Universidad Nacional de Salta, 4400 Salta (AR))

1989-04-01

103

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

104

Spectral pH dependence of erythrosin B in sol-gel silica coatings and buffered solutions  

Microsoft Academic Search

Thin coatings optically sensitive against pH are obtained by entrapping erythrosin B molecules in a sol-gel silica matrix. Comparisons between optical spectra of erythrosin B in solutions and those once entrapped in silica coatings are performed for pH ranging from 0.5 to 12.0. Significant differences between both kinds of spectra (solutions and coatings) of erythrosin B are observed. Main changes

E. MONTERO; M. A. GARCÍA; M. A. VILLEGAS; J. LLOPIS

105

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

NASA Technical Reports Server (NTRS)

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

Gibson, Ursula J.

1999-01-01

106

In-line desalting of proteins from buffer and synthetic urine solution prior to ESI-MS analysis via a capillary-channeled polymer fiber microcolumn.  

PubMed

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. PMID:23463546

Burdette, Carolyn Q; Marcus, R Kenneth

2013-06-01

107

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

108

Buffered Routing Tree Construction under Buffer  

E-print Network

1 Buffered Routing Tree Construction under Buffer Placement Blockages Wei Chen, Massoud Pedram Dept;2 Previous Work Insert buffers into a pre-determined net topology Van Ginneken '90 Insert buffers while generating the net topology (using a set of buffer stations) Two-pin nets: Zhou '99, Jagannathan '00 Multi

Pedram, Massoud

109

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

110

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

PubMed

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

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

1996-02-01

111

Phosphorus concentrations in soil and subsurface water: a field study among cropland and riparian buffers.  

PubMed

Riparian buffers can be effective at removing phosphorus (P) in overland flow, but their influence on subsurface P loading is not well known. Phosphorus concentrations in the soil, soil solution, and shallow ground water of 16 paired cropland-buffer plots were characterized during 2004 and 2005. The sites were located at two private dairy farms in Central New York on silt and gravelly silt loams (Aeric Endoaqualfs, Fluvaquentic Endoaquepts, Fluvaquentic Eutrudepts, Glossaquic Hapludalfs, and Glossic Hapludalfs). It was hypothesized that P availability (sodium acetate extractable-P) and soil-landscape variability would affect P release to the soil solution and shallow ground water. Results showed that P availability tended to be greater in crop fields relative to paired buffer plots. Soil P was a good indicator of soil solution dissolved (<0.45 microm) molybdate-reactive P (DRP) concentrations among plots, but was not independently effective at predicting ground water DRP concentrations. Mean ground water DRP in corn fields ranged from < or =20 to 80 microg L(-1), with lower concentrations in hay and buffer plots. More imperfectly drained crop fields and buffers tended to have greater average DRP, particulate (> or =0.45 microm) reactive P (PRP), and dissolved unreactive P (DUP) concentrations in ground water. Soil organic matter and 50-cm depth soil solution DRP in buffers jointly explained 75% of the average buffer ground water DRP variability. Results suggest that buffers were relatively effective at reducing soil solution and shallow ground water DRP concentrations, but their impact on particulate and organic P in ground water was less clear. PMID:18178879

Young, Eric O; Briggs, Russell D

2008-01-01

112

A new approach in biomimetic synthesis of calcium phosphate coatings using lactic acid–Na lactate buffered body fluid solution  

Microsoft Academic Search

The main objective of this study was to investigate calcium phosphate (CaP) coatings on Ti6Al4V substrates by using the biomimetic technique. To this purpose, a new solution was developed to coat CaP on Ti6Al4V alloy substrates. The newly formulated body fluid (Lac-SBF) contained appropriate amounts of sodium lactate (NaL) and lactic acid (HL), as well as all the other ionic

Ahmet Pasinli; Mithat Yuksel; Erdal Celik; Sevil Sener; A. Cuneyt Tas

2010-01-01

113

Anodically generated cobalt(III) acetate as reagent for coulometric titrations in acetic acid  

Microsoft Academic Search

Summary Conditions for the anodic generation of cobalt(III) acetate with high current efficiency in non-aqueous solutions of potassium acetate in acetic acid have been investigated. The presence of water or acetic anhydride in the anolyte diminishes the amount of the generated oxidant. The stability of the generated cobalt(III) acetate solution is decreased in the presence of water and at elevated

T. J. Pastor; I. ?iri?

1985-01-01

114

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

115

Reevaluation of the First and Second Stoichiometric Dissociation Constants of Oxalic Acid at Temperatures from 0 to 60?°C in Aqueous Oxalate Buffer Solutions with or without Sodium or Potassium Chloride  

Microsoft Academic Search

Equations were developed for the calculation of the first stoichiometric (molality scale) dissociation constant (K\\u000a m1) of oxalic acid in buffer solutions containing oxalic acid, potassium hydrogen oxalate, and potassium chloride from the determined\\u000a thermodynamic values of this dissociation constant (K\\u000a a1) and the molalities of the components in the solutions. Similar equations were also developed for the second stoichiometric

Jaakko I. Partanen; Pekka M. Juusola; Arthur K. Covington

2009-01-01

116

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

117

BUFFER OVERFLOW -Eswar Balasubramanian  

E-print Network

BUFFER OVERFLOW -Eswar Balasubramanian ECE578 #12;Precursor How serious is this BO? n Number the stack n Exploit n Prevention #12;Buffer Overflow n Copying more data into a buffer than it could hold and ebp adjusted accordingly /* vulnerable.c */ int main() { char buffer[500]; gets(buffer); return 0

118

Electrofocusing in Buffers.  

National Technical Information Service (NTIS)

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

A. Chrambach, N. Y. Nguyen

1977-01-01

119

Buffer Preparation (Gozani Lab) 1. 1 M Tris-HCl Buffers  

E-print Network

Buffer Preparation (Gozani Lab) 1. 1 M Tris-HCl Buffers pH Volume (L) TrisBase (g) HCl (ml) pH 7 by NaOH is essential for solubility. Autoclavable. 3. TAE DNA Electrophoresis Buffer (50 X) (2 M Tris, add 400 ml 50X buffer into 19.6 L ddH2O. 4. SDS-PAGE Gel Solutions Vol (L) Tris (g) HCl (ml) 10% SDS

Gozani, Or

120

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

Microsoft Academic Search

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

JoãoPedro Ferreira; JoãoAlexandre Rodrigues; InêsTeodoraElias da Fonseca

2004-01-01

121

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

122

Comparison of different methods for calculation of the stoichiometric dissociation constant of acetic acid from results of potentiometric titrations at 298.15 K in aqueous sodium or potassium chloride solutions  

Microsoft Academic Search

Single-ion activity coefficient equations were determined for the calculation of the molality-scale dissociation constants, Km, for acetic acid in aqueous NaCl or KCl solutions at 298.15 K. The salt alone determines the ionic strength, Im, of the solutions considered in this study. The activity coefficient equations are of the Hückel type, and Km can be calculated by those for a

Jaakko I. Partanen; Pekka M. Juusola

2000-01-01

123

Labradorite dissolution in aqueous organic acid solutions: an experimental study  

E-print Network

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

Ahmed, MD. Raquib Uddin

2012-06-07

124

Studies on electrochemical characterization and performance prediction of cellulose acetate and Zeocarb-225 composite membranes in aqueous NaCl solutions.  

PubMed

We have mixed cellulose acetate and Zeocarb-225 in different ratios, leading to the preparations of Membrane-1 and Membrane-2. Membrane potential, water content, and conductance measurements have been carried out to estimate and analyze the data in terms of equilibria and important electrochemical parameters. The Donnan equilibrium has been incorporated to estimate the activity coefficient of counterions, y(p)M, and solute, y(+/-)M in the membrane phase along with the parameter, so called varphi expressing non-ideality. Dependence of the extent of hydrophilicity of both membranes on mean electrolyte concentrations has been examined. Selectivity in membranes is discussed in terms of dissociation equilibria, K(d)s and K(d)f. It has been found that membrane surface charge density sigma(s) increases with increasing of external NaCl concentration. Dependence of water transport number and cationic transport number on electrolyte concentration shows a similar trend of variation. At higher mean concentration of electrolyte, water transport number in Membrane-2 has a negative value. Membrane-2 has a higher value of water transport number than Membrane-1. The entropy production due to solute and water transport has been quantified for both the membranes in the light of nonequilibrium thermodynamics. The various type of interactions such as solute-membrane, solute-water, and water-membrane are analyzed in terms of friction coefficients (f(ij)) of Spiegler's frictional pore model. In our case, an f(wm) < f(sm) < f(sw)-like trend is observed in both membranes. These frictional coefficients show close dependence on external electrolyte concentrations. Pore potential values of Membrane-1 and Membrane-2 have been worked out using the Poisson-Boltzmann equation. In both systems pore potential values increase with increasing mean electrolyte concentrations. The transport through Membrane-1 and Membrane-2 tends to follow diffusion-control criteria, i.e., (D(+/-) . C. d/D(+/-)M C(M) . delta) > 2. A slightly higher value of solute rejection is found in Membrane-2. PMID:16499917

Tiwari, A K; Ahmad, Suhail

2006-06-01

125

Kinetics of chemical degradation of isoxaflutole: influence of the nature of aqueous buffers (alkanoic acid/sodium salt vs phosphate).  

PubMed

A kinetic study of the chemical degradation of isoxaflutole (5-cyclopropyl-1,2-oxazol-4-yl alpha alpha alpha-trifluoro-2-mesyl-p-tolyl ketone) into its diketonitrile derivative (DKN), which is its active herbicide principle, in organic buffers at different pH values was carried out using a HPLC/UV detection method. The values of the pseudo-first-order rate constants Kobs for the reaction were calculated and compared with those previously obtained in inorganic buffers. In both cases, Kobs was found to be dependent on pH and temperature, but at pH 5.2 the degradation of isoxaflutole in CH3COOH/CH3COONa buffers was considerably faster than in KH2PO4/Na2HPO4 buffers, indicating that the compound was sensitive to the nature of the reagents used to prepare buffered solutions. The influence of phosphate and acetate concentrations and the influence of the R-substituent in RCOOH/RCOONa buffers were investigated. For the HA/A- buffers studied, the values of Kobs were linearly dependent on HA and A- concentrations, which meant that the degradation of isoxaflutole was subject to general catalysis. The values of Kobs were also found to be dependent on the number and the position of the CH3 groups of the R-substituent. The known degradation product of DKN (a benzoic acid derivative) was not detected throughout this study. PMID:11455816

Beltran, E; Fenet, H; Cooper, J F; Coste, C M

2001-04-01

126

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

NASA Astrophysics Data System (ADS)

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

Cao, Youfang; Liang, Jie

2013-07-01

127

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

128

DESOXYCORTICOSTERONE ACETATE  

PubMed Central

1. Desoxycorticosterone acetate (DCA) and NaCl, in the dosage employed in normal rats, caused renal and cardiac hypertrophy, characteristic changes in the renal tubular epithelium, atrophic changes in the subcapsular zone of the adrenal cortex, and serum electrolyte changes characterized by a rise in sodium and fall in potassium. 2. In rats rendered nephritic with a rabbit anti-rat-kidney serum, the same regimen caused similar changes. In addition, DCA given concurrently with NaCl greatly intensified the nephritic process and gave rise to striking arterial hypertension. 3. A diet, virtually sodium-free, administered to normal and nephritic rats receiving daily injections of DCA abolished or reduced to a minimum the effects of this steroid; i.e., a liberal ingestion of NaCl was essential for the potentiation of the action of DCA. 4. The addition of KCl to the drinking water of rats receiving DCA and NaCl tended to correct the depression of the level of potassium in the serum, but had no effect upon the hypertension in nephritic animals nor upon the anatomical lesions. 5. The mechanism by which the sodium ion potentiates the activity of DCA has not been established. PMID:19871607

Knowlton, Abbie I.; Loeb, Emily N.; Stoerk, Herbert C.; Seegal, Beatrice C.

1947-01-01

129

Single Simulation Buffer Optimization  

NASA Astrophysics Data System (ADS)

The performance of manufacturing systems can be adjusted by allocation buffer into the manufacturing system. Buffer will improve the performance of manufacturing systems by improving the utilization of the constraints; yet buffer will also increase the makespan and the work in progress. Due to the complex nature of the systems, buffer allocation is usually difficult to optimize. This paper presents a prediction model of the effect of buffer based on the shifting bottleneck detection and a blocking and starving analysis. The prediction model is used to optimize the buffer allocation using only a single simulation.

Roser, Christoph; Nakano, Masaru; Tanaka, Minoru

130

Sizing router buffers  

Microsoft Academic Search

All Internet routers contain buffers to hold packets during times of congestion. Today, the size of the buffers is determined by the dynamics of TCP's congestion control algorithm. In particular, the goal is to make sure that when a link is congested, it is busy 100% of the time; which is equivalent to making sure its buffer never goes empty.

Guido Appenzeller; Isaac Keslassy; Nick McKeown

2004-01-01

131

Buffer strips trap contaminants  

E-print Network

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

Nebraska-Lincoln, University of

132

Development of an Amperometric Acetic Acid Sensor in Organic System  

Microsoft Academic Search

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

Shin Lin; Tse-Chuan Chou

133

VIRTUAL FRAME BUFFER INTERFACE  

NASA Technical Reports Server (NTRS)

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

Wolfe, T. L.

1994-01-01

134

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

Microsoft Academic Search

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

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

2005-01-01

135

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

136

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

137

Thermophysical properties of lysozyme (protein) solutions  

NASA Technical Reports Server (NTRS)

Thermophysical properties of protein solutions composed of the lysozyme crystals with a 0.1 M sodium acetate and 5 percent NaCl solution as the buffer (pH = 4.0) are determined. The properties being measured include specific heat, thermal conductivity, dynamic viscosity, and surface tension. The protein concentrations are varied. Thermal diffusivity is calculated using the measured results. The purpose of the research is to measure thermophysical properties of lysozyme solutions which would serve as the data bank for controlling and modeling the crystal growth process on earth as well as in space.

Liu, Jiaching; Yang, Wen-Jei

1992-01-01

138

Organellar calcium buffers.  

PubMed

Ca(2+) is an important intracellular messenger affecting many diverse processes. In eukaryotic cells, Ca(2+) storage is achieved within specific intracellular organelles, especially the endoplasmic/sarcoplasmic reticulum, in which Ca(2+) is buffered by specific proteins known as Ca(2+) buffers. Ca(2+) buffers are a diverse group of proteins, varying in their affinities and capacities for Ca(2+), but they typically also carry out other functions within the cell. The wide range of organelles containing Ca(2+) and the evidence supporting cross-talk between these organelles suggest the existence of a dynamic network of organellar Ca(2+) signaling, mediated by a variety of organellar Ca(2+) buffers. PMID:21421925

Prins, Daniel; Michalak, Marek

2011-03-01

139

Buffer Therapy for Cancer  

PubMed Central

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

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

2013-01-01

140

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

PubMed

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

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

1996-01-01

141

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

142

Immunolocalization of MAP-2 in Routinely Formalin-Fixed, Paraffin-Embedded Guinea Pig Brain Sections Using Microwave Irradiation: A Comparison of Different Combinations of Antibody Clones and Antigen Retrieval Buffer Solutions  

NASA Astrophysics Data System (ADS)

The present study was designed to evaluate the efficacy of different microwave pretreatment methods to retrieve microtubule-associated protein 2 (MAP-2) immunoreactivity in formalin-fixed, paraffin-embedded guinea pig brain sections. Brain sections, microwave pretreated in boiling sodium citrate, citric acid, Tris hydrochloride, and EDTA buffers of pH 4, 6, and 8, were labeled with four different clones of MAP-2 monoclonal antibodies. No MAP-2 immunoreactivity was observed in control sections processed without microwave pretreatment. Optimal MAP-2 immunoreactivity was observed only when MAP-2 antibody clone AP18 was used in conjunction with citric acid buffer of pH 6.0. Using this combination, brain sections from nerve agent soman-exposed guinea pigs were found to exhibit marked reduction in MAP-2 immunostaining in the hippocampus. These observations suggest that the clone of the antibody in addition to the type and pH of antigen retrieval (AR) solution are important variables to be considered for establishing an optimal AR technique. When studying counterpart antigens of species other than that to which the antibodies were originally raised, different antibody clones must be tested in combination with different microwave-assisted AR (MAR) methods. This MAR method makes it possible to conduct retrospective studies on archival guinea pig brain paraffin blocks to evaluate changes in neuronal MAP-2 expression as a consequence of chemical warfare nerve agent toxicity.

Kan, Robert K.; Pleva, Christina M.; Hamilton, Tracey A.; Petrali, John P.

2005-04-01

143

Optimal trellis-based buffered compression and fast approximations  

Microsoft Academic Search

The authors formalize the description of the buffer-constrained adaptive quantization problem. For a given set of admissible quantizers used to code a discrete nonstationary signal sequence in a buffer-constrained environment, they formulate the optimal solution. They also develop slightly suboptimal but much faster approximations. These solutions are valid for any globally minimum distortion criterion, which is additive over the individual

Antonio Ortega; Kannan Ramchandran; Martin Vetterli

1994-01-01

144

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

NASA Astrophysics Data System (ADS)

We introduce a new method to fabricate a MoO3 hole-transporting layer for organic photovoltaic cells (OPVs). We fabricated a MoS2 film from its solution and converted it to MoO3. MoS2 has a lamellar crystal structure similar to graphite, and it can be exfoliated into monolayer MoS2 dispersible in water. Li atoms were first intercalated into van der Waals gaps of MoS2, and the compound was immersed in water to generate H2 bubbles, which broke the van der Waals bond between adjacent MoS2 layers. The produced solution of MoS2 was spin-casted on an indium tin oxide substrate, and the film was oxidized by ozone. On the converted MoO3 hole-transporting layer, an organic photoconversion layer was fabricated by spin-casting a poly(3-hexylthiophene):[6,6]-phenyl-C61 butyric acid methyl ester (P3HT:PCBM) composite solution. Fabricated OPVs revealed a power conversion efficiency as large as 3.14%, which was superior to that of P3HT/PCBM OPV with a poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hole-transporting layer.

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

2011-07-01

145

Synthesis, optical and thermal studies on novel semi organic nonlinear optical Urea Zinc Acetate crystals by solution growth technique for the applications of optoelectronic devices  

NASA Astrophysics Data System (ADS)

Urea Zinc Acetate (UZA), a novel semi organic nonlinear optical crystal having dimensions 30×28×10 mm3 has been synthesized using slow evaporation technique. The lattice parameters for the grown crystals were determined using single crystal XRD. The presence of functional groups for the grown crystals was confirmed using Fourier Transform Infrared (FT-IR) spectroscopy. The optical absorption studies show that the material has wide optical transparency in the entire visible region. The thermal stability of the crystal was determined from thermo gravimetric and differential thermal analysis curve. The second harmonic generation was confirmed by Kurtz powder method and it is found to be 3 times than that of KDP crystal.

Chithambaram, V.; Krishnan, S.

2014-02-01

146

A buffer diverter system  

NASA Astrophysics Data System (ADS)

The prevention of sympathetic detonations between donor and acceptor bombs, which are stored lying horizontally lying parallel to each other, is accomplished using a buffer diverter system. One example of a buffer diverter system is a pair of molded concrete bases, each supporting a horizontal bomb and conforming to the shape of its respective bomb up to its horizontal centerline. In the first example, the entire space between the two molded concrete bases and bombs is filled in with a buffer which has sufficient width to attenuate the shock of detonation down pressure levels below a pressure threshold needed to induce an acceptor bomb to sympathetically detonate. In another example of a buffer diverter system, the buffer is replaced with a diverter. The diverter is an I-beam which abuts each bomb at its horizontal centerline and runs the length of the two bombs. The I-beam has the same width as the buffer, but its surface area presented to each bomb is nearly the minimum required to deflect fragments from the silhouette of the acceptor bomb.

Foster, J. C., Jr.

1985-07-01

147

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

148

Cellulose acetate electrospun fiber mats for controlled release of silymarin.  

PubMed

In this research, the silymarin-loaded electrospun cellulose acetate (CA) fibers were prepared which containing silymarin in various amounts (i.e., 2.5-20 wt.% based on the weight of CA powder). Incorporation of silymarin in the neat CA solution did not affect the morphology of the resulting fibers, as both the neat and the silymarin-loaded CA fibers were smooth. The average diameters of silymarin-loaded CA fiber ranged between 550-900 nm. No presence of the silymarin aggregates of any kind was observed on the surfaces of these fibers, suggesting that the silymarin was encapsulated well within the fibers. These results were confirmed by lowering the glass transition temperature and the melting temperature of the silymarin-loaded electrospun CA fibers which is determined by DSC technique. The release characteristic of silymarin from the silymarin-loaded CA fiber mats was investigated by the total immersion in the solution of 1/1 phosphate buffer/methanol medium pH 7.4 at 37 degrees C. The silymarin release from the silymarin-loaded electrospun CA fiber mat is monotonously increased to reach the maximum value at 480 min. The maximum amount of silymarin released from these materials increases with the increasing of initial silymarin loading in the spinning CA solutions. Since no aggregation of silymarin was found on the surface of the silymarin-loaded fibers, the release of the silymarin from fiber mats was mainly by the diffusion. PMID:22524059

Phiriyawirut, Manisara; Phaechamud, Thawatchai

2012-01-01

149

REMOTE Shared Memory Buffer #2  

E-print Network

#12;#12;#12;#12;#12;#12;REMOTE Shared Memory Buffer #2 Computer or BackPlane #2 Computer or BackPlane #3 LOCAL Processes Processes #5 NML Server for Buffer #1 NML Server for Buffer #2 ProcessProcessProcess #4 #6 Process Process Process #3#2#1 Computer or BackPlane #1 Shared Memory Buffer #1 #12

150

Tetragonal Chicken Egg White Lysozyme Solubility in Sodium Chloride Solutions  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

151

Acetate and Formate Stress: Opposite Responses in the Proteome of Escherichia coli  

Microsoft Academic Search

Acetate and formate are major fermentation products of Escherichia coli. Below pH 7, the balance shifts to lactate; an oversupply of acetate or formate retards growth. E. coli W3110 was grown with aeration in potassium-modified Luria broth buffered at pH 6.7 in the presence or absence of added acetate or formate, and the protein profiles were compared by two-dimensional sodium

CHRISTOPHER KIRKPATRICK; LISA M. MAURER; NIKKI E. OYELAKIN; YULIYA N. YONCHEVA; RUSSELL MAURER; JOAN L. SLONCZEWSKI

2001-01-01

152

Sodium acetate infusion in critically ill trauma patients for hyperchloremic acidosis  

Microsoft Academic Search

Introduction  Sodium acetate has been shown to cause hemodynamic instability when used as a hemodialysis buffer. The pattern of hemodynamic\\u000a response to injury will be evaluated between those who received sodium acetate and those who did not.\\u000a \\u000a \\u000a The primary purpose of the study is to analyze the effect of sodium acetate on hemodynamic parameters. Secondarily we looked\\u000a at the effects on

Andrew McCague; Mira Dermendjieva; Ryan Hutchinson; David T Wong; Nguyen Dao

2011-01-01

153

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

PubMed

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

Das Gupta, V; Stewart, K R

1985-03-01

154

Riparian Forest Buffer Restoration TRiparian Forest Buffer Restoration TRiparian Forest Buffer Restoration TRiparian Forest Buffer Restoration TRiparian Forest Buffer Restoration Targetingargetingargetingargetingargeting for the Yfor the Yfor the Yfor the  

E-print Network

1 Riparian Forest Buffer Restoration TRiparian Forest Buffer Restoration TRiparian Forest Buffer Restoration TRiparian Forest Buffer Restoration TRiparian Forest Buffer Restoration resource that protects water quality" (Riparian Forest Buffers, 1996). In addition to protecting water

155

[Preparation and testing of buffers for fibrinogen].  

PubMed

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

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

1994-01-01

156

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

157

Principles of database buffer management  

Microsoft Academic Search

This paper discusses the implementation of a database buffer manager as a component of a DBMS. The interface between calling components of higher system layers and the buffer manager is described; the principal differences between virtual memory paging and database buffer management are outlined; the notion of referencing versus addressing of database pages is introduced; and the concept of fixing

Wolfgang Effelsberg; Theo Haerder

1984-01-01

158

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

E-print Network

Author's personal copy Evaluation of stainless steel cathodes and a bicarbonate buffer for hydrogen: Biohydrogen Bioenergy Gas bag Buffer Electrohydrogenesis a b s t r a c t Microbial electrolysis cells (MECs) are often examined for hydrogen production using non- sustainable phosphate buffered solutions (PBS

159

Mail-System insert.remove.BUFFER  

E-print Network

Beispiel: Mail-System MS := (FILE j BUFFER[f FM ] j BUFFER[f MF ] j MAIL j DELIVER j BUFFER[f CM : insert 7! xy insert remove 7! xy remove empty 7! xy empty #12; BUFFER := insert.remove.BUFFER + empty.BUFFER.DELIVER) COLLECT := letter posted .cm insert.COLLECT #12; Beispiel: Mail-System FILE BUFFER[f MF ] BUFFER[f FM

Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

160

Virtual Frame Buffer Interface Program  

NASA Technical Reports Server (NTRS)

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

Wolfe, Thomas L.

1990-01-01

161

Acidbase interaction in the acetic acid-acetic anhydride system  

Microsoft Academic Search

1.The electroconductivity and dielectric permeability of the acetic acid-acetic anhydride system have been measured. The electroconductivity of the system has a maximum close to 50% of the anhydride. The curve of the dielectric permeability is concave toward the composition axis.2.The dependence of the electroconductivity on the composition is explained by the formation of a complex between acetic acid and acetic

V. E. Bel'skii; M. I. Vinnik

1963-01-01

162

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

163

Buffering in optical packet switches  

Microsoft Academic Search

This paper consists of a categorization of optical buffering strategies for optical packet switches, and a comparison of the performance of these strategies both with respect to packet loss\\/delay and bit error rate (BER) performance. Issues surrounding optical buffer implementation are discussed, and representative architectures are introduced under different categories. Conclusions are drawn about packet loss and BER performance, and

David K. Hunter; Meow C. Chia; Ivan Andonovic

1998-01-01

164

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

165

Role of luminal buffers in renal tubular acidification  

Microsoft Academic Search

Summary The acidification kinetics of artificial solutions containing buffers of different permeancy were studied in rat proximal tubules by means of stationary microperfusion techniques. Luminal pH changes were measured by antimony microelectrodes and used to calculate net rates of acidification and the approach to steady-state pH levels. For most buffer species, tracer efflux out of the lumen was compared with

V. L. Costa Silva; S. S. Campiglia; M. de Mello Aires; G. Malnic; G. Giebisch

1981-01-01

166

A Procedure for the Joint Evaluation of Substrate Partitioning and Kinetic Parameters for Reactions Catalyzed by Enzymes in Reverse Micellar Solutions  

Microsoft Academic Search

A simple method useful for the joint evaluation of substrate partitioning and kinetic parameters for reactions catalyzed by enzymes entrapped in reverse micelles is proposed. The method is applied to the hydrolysis of 2-naphthyl acetate (2-NA) catalyzed by lipase in sodium 1,4-bis(2-ethylhexyl) sulfosuccinate (AOT)\\/buffer\\/heptane reverse micellar solutions. In the presence of micelles, the relationship between the initial reaction rate and

Luis Felipe Aguilar; Elsa Abuin; Eduardo Lissi

2001-01-01

167

Message Buffering in Epidemic Data Dissemination  

E-print Network

Message Buffering in Epidemic Data Dissemination I. This work is supported in part by TUBITAK (The is the buffer space used by individual peers of the group. Our aim is to optimize the buffer space while and compare it with a hash- based approach for buffer management. The effect of short and long term buffering

Caglar, Mine

168

Pb(II) and Zn(II) adsorption onto Na-and Ca-montmorillonites in acetic acid/acetate medium: Experimental approach and geochemical modelling  

E-print Network

/acetate as buffer at pH 5 in order to reproduce a biodegradable leachate of a young landfill. These experiments environmental impacts related to landfill leachate are pollution of groundwater and surface water. European landfill (5-10 years), and stabilized for an old landfill (> 10 years). The biodegradable leachate

Paris-Sud XI, Université de

169

A gradient technique for general buffer storage design in a production line  

Microsoft Academic Search

In this paper, we present a complete and novel solution to the well known buffer storage design problem in a serial production line. The key ingredient of the solution is the efficient calculation of the gradient vector of the throughput with respect to the various buffer sizes. Analytical and experimental results are presented.

Y. C. HO; M. A. EYLER; T. T. CHIEN

1979-01-01

170

Understanding the Science Behind Riparian Forest Buffers  

E-print Network

Understanding the Science Behind Riparian Forest Buffers: Resources for Virginia Landowners #12 Forest Buffers: Resources for Virginia Landowners by Julia C. Klapproth and James E. Johnson forest buffers can provide many benefits to society through improved water quality, reduced flooding

Liskiewicz, Maciej

171

Branch target buffer design and optimization  

NASA Technical Reports Server (NTRS)

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

Perleberg, Chris H.; Smith, Alan J.

1993-01-01

172

Reformulation of a new vancomycin analog: an example of the importance of buffer species and strength.  

PubMed

The purpose of this research was to use our previously validated dynamic injection apparatus as a rapid method for screening pH-adjusted formulations of a new vancomycin analog, Van-An, for their potential to precipitate upon dilution. In 1 vial, Van-An was reconstituted according to the manufacturer's instructions. In a separate vial, the Van-An formulation's existing phosphate buffer species was supplemented with acetate buffer, which has a pKa in the desired range: between the pH values of the formulation (pH 3.9) and blood (pH 7.4). The formulations were injected using the dynamic injection apparatus into a flowing stream of isotonic Sorensen's phosphate buffer at rates of 0.25, 0.5, 1, and 2 mL/min. The peaks obtained with the spectrophotometer were reproducible for each injection rate/formulation combination. For the phosphate-buffered formulation, the least amount of precipitation was obtained at the 0.25 mL/min injection rate. Acetate buffer was able to substantially reduce such precipitation, even at the highest injection rate. The opacity peaks for the formulation with the acetate addition were significantly smaller (P < .05) than those obtained for the unaltered formulation at all 4 injection rates. The results suggest that acetate is a better buffer species than phosphate for the pH range defined. Furthermore, we present evidence to support a generally applicable approach to screening new formulations of drug products that may be clinically useful for reducing the incidence of phlebitis in humans. PMID:16584164

Johnson, Jennifer L H; Yalkowsky, Samuel H

2006-01-01

173

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

174

An economical new process for incenter bicarbonate dialysate production: comparison with acetate in a large dialysis population.  

PubMed

It is generally agreed that bicarbonate dialysate is preferable to acetate dialysate, but the major limiting factors of high cost and technical difficulty in maintaining its stability for prolonged periods preclude its widespread use. The procedure developed by the authors stabilizes bicarbonate dialysate for up to 4 days, rendering bicarbonate dialysate feasible for routine out-patient use. HCO3 dialysate is produced in our dialysis unit after an initial investment of $10,000.00, at a cost per 4-h treatment of $1.22 at a dialysate flow of 500 cc/min. One hundred fifty-one chronic dialysis patients participated in an 18-week study to evaluate clinical symptomatology when bicarbonate was substituted for acetate as the dialysis base buffer. Evaluation of each dialysis treatment (total of 8,183 treatments) consisted of both subjective and objective criteria (vomiting, angina, cramps, hypotension, and frequency of use of mannitol, hypertonic saline, and nitroglycerine). The patients were unaware of the change in dialysate solutions. There was a significant reduction (p less than 0.001) in the incidence of vomiting, cramps, hypotension, nausea, flushing, and the use of mannitol and hypertonic saline during bicarbonate dialysate treatment compared with acetate dialysate. Shortness of breath, angina, mental confusion, and paresthesias were not statistically changed. Although the method of HCO3 dialysate production is associated with occasional higher bacterial count than currently recommended by AAMI standards, no adverse reactions were observed in patients treated with standard efficiency dialyzers. It is concluded that the process for incenter HCO3 production is safe, economical, and better tolerated than acetate dialysate. PMID:2803052

Oettinger, C W; Oliver, J C

1989-10-01

175

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

PubMed

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

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

2009-08-01

176

Buffer Tank Design for Acceptable Control Performance  

E-print Network

Buffer Tank Design for Acceptable Control Performance Audun Faanes and Sigurd Skogestad for the design of buffer tanks. We consider mainly the case where the objective of the buffer tank is to dampen-mail: skoge@chemeng.ntnu.no, Tel.: +47 73 59 41 54, Fax.: +47 73 59 40 80 1 #12;1 Introduction Buffer tanks

Skogestad, Sigurd

177

Acetic Acid Catalyzed Carbon Aerogels  

Microsoft Academic Search

We prepared carbon aerogels with a wide range of structural properties and densities using the weak acetic acid as a catalyst. Two series of acetic acid catalyzed carbon aerogels with different dilution of the catalyst and the monomers were investigated accurately. Structural investigation was performed via (U)SAXS, gas sorption and SEM. The pore and particle size can be tailored according

R. Brandt; R. Petricevic; H. Pröbstle; J. Fricke

2003-01-01

178

Acetate metabolism in Methanothrix soehngenii  

Microsoft Academic Search

Acetate is quantitatively the most important intermediate in the anaerobic degradation of soluble organic matter. The conversion rate of acetate by methanogenic bacteria is proposed to be the rate limiting step in this degradation The study of acetoclastic methanogens, therefore is of relevance to our understanding of anaerobic processes and their optimal application in treatment of waste water from various

M. S. M. Jetten

1991-01-01

179

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

180

Agarose gel electrophoresis Solutions and reagents  

E-print Network

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

Abou Elela, Sherif

181

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

182

In Vitro EGF Receptor Autophosphorylation Buffers Needed  

E-print Network

1 In Vitro EGF Receptor Autophosphorylation Buffers Needed: Lysis Buffer: 25 mM HEPES, pH 7.2, 1 mM PMSF, 1 mM EDTA, 2 µg/ml leupeptin, 1 µg/ml pepstatin and 1 µg/ml 2-macroglobulin. Assay Buffer: 70 m buffered saline to remove serum proteins. 2. Approximately 3 to 5 ml lysis buffer is added to the plate

Pike, Linda J.

183

Buffered Routing Tree Construction Under Buffer Placement Interconnect delay has become a critical factor in  

E-print Network

1 Buffered Routing Tree Construction Under Buffer Placement Blockages Abstract Interconnect delay and buffering are powerful means of improving the circuit speed and correcting the timing violations after net topology construction and buffer insertion and sizing simultaneously under the given buffer

Pedram, Massoud

184

Distributed communication via global buffer  

Microsoft Academic Search

Design and implementation of an inter-address-space communication mechanism for the SBN network computer are described. SBN's basic communication primitives appear in context of a new distributed systems programming language strongly supported by the network communication kernel. A model in which all communication takes place via a distributed global buffer results in simplicity, generality and power in the communication primitives. Implementation

David Gelernter; Arthur J. Bernstein

1982-01-01

185

Effects of PH, CO2, and Buffering Systems on Lactic Acid Production in Rat Liver Slices.  

National Technical Information Service (NTIS)

In an effort to reveal the separate effects of pH, CO2, and the type of buffering agent on lactate production, rat liver slices were incubated in Krebs-Ringer solution using three different buffers equilibrated with either O2 or 5% CO2 in O2 and at three ...

W. G. Soucie

1969-01-01

186

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

E-print Network

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

Pedram, Massoud

187

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

PubMed

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. PMID:23651742

Liu, Xiangxiang; Wan, Yiqun

2013-07-01

188

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

189

The .alpha.-cyano-.alpha.-phenylacetic acid keto-enol system. Flash photolytic generation of the enol in aqueous solution and determination of the keto-enol equilibrium constants and acid dissociation constants interrelating all keto and enol forms in that medium  

Microsoft Academic Search

The enol of a-cyano-a-phenylacetic acid was observed as a short-lived transient species formed upon flash photolytic generation of phenylcyanoketene by a photo-Wolff reaction of a-cyano-a-diazoacetophenone followed by hydration of the ketene. Rates of ketonization of the enol were measured in dilute hydrochloric acid solutions and acetic acid, biphosphate ion, tris(hydroxymethyl)methylamine, and ammonia buffers; this gave a rate profile with turning

J. Andraos; Y. Chiang; A. J. Kresge; I. G. Pojarlieff; N. P. Schepp; J. Wirz

1994-01-01

190

Laser velocimeter (autocovariance) buffer interface  

NASA Technical Reports Server (NTRS)

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

Clemmons, J. I., Jr.

1981-01-01

191

Electrically generated lead(IV) acetate and manganese(III) acetate as reagents for coulometric redox titrations in acetic acid  

Microsoft Academic Search

Summary The conditions were investigated for electrochemical generation of lead(IV) acetate in acetic acid by oxidation of lead(II) acetate on a lead dioxide electrode and on a platinum electrode. Bivalent manganese ions are quantitatively oxidized on a platinum electrode to the tervalent state in the same solvent. Coulometric titration methods for the determination of small amounts of hydroquinone in acetic

Tibor J. Pastor; Vilim J. Vajgand; Zorica Kicovic

1976-01-01

192

Effects of Acetic Acid Pretreatment and Hot Air Drying on Resistance of Salmonella on Cabbage Slices  

Microsoft Academic Search

The heat resistance of Salmonella anatum inoculated onto the surface of cabbage slices as affected by acetic acid pretreatment (0.5–1.5% v\\/v) and hot air drying at 50–60°C was investigated. Approximately 1.5 log10 of Salmonella numbers was reduced after soaking the vegetables in acetic acid solution. The inhibitory effect of acetic acid on the bacteria was more pronounced during drying. The heat

Naphaporn Chiewchan; Pornpen Morakotjinda

2009-01-01

193

Study of Buffer Size in Internet Routers.  

National Technical Information Service (NTIS)

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

D. Towsley

2006-01-01

194

Buffer management in relational database systems  

Microsoft Academic Search

The hot-set model, characterizing the buffer requirements of relational queries, is presented. This model allows the system to determine the optimal buffer space to be allocated to a query; it can also be used by the query optimizer to derive efficient execution plans accounting for the available buffer space, and by a query scheduler to prevent thrashing. The hot-set model

Giovanni Maria Sacco; Mario Schkolnick

1986-01-01

195

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...

196

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

197

X-ray diffraction, solution structure, and computational studies on derivatives of (3-sec-butyl-2,3-dihydro-1H-isoquinolin-4-ylidene)acetic acid: compounds with activity as calpain inhibitors.  

PubMed

A thorough experimental and computational study of derivatives of (3-sec-butyl-2,3-dihydroisoquinolin-4-ylidene)acetic acid was performed. Some of these compounds are calpain inhibitors and could be useful as therapeutic agents, since this enzyme is a Ca(2+)-dependent cysteine protease involved in a wide variety of metabolic and physiological processes, whose over-activation is associated to several pathological conditions. To gain a better understanding of the structure-activity relationships, a structural analysis was carried out with (1)H and (13)C NMR spectroscopy and DFT calculations together with the X-ray diffraction data of three compounds. The solid state structures showed that the crystal packing as well as the intermolecular interactions depend on the substituent nature of the COOR group. Also, the reactivity of the exocyclic double bond was theoretically evaluated, finding that the more reactive compound is the most potent inhibitor of calpain (IC(50) = 25 nM). PMID:20014819

Alonso, Mercedes; Chicharro, Roberto; Miranda, Carlos; Arán, Vicente J; Maestro, Miguel A; Herradón, Bernardo

2010-01-15

198

Thermal decomposition of pyridine-substituted cobaltic acetate in acetic acid.  

PubMed

The thermal decomposition of [py(3)Co(3)O(OAc)(5)OH][PF(6)] in acetic acid solution in the absence of oxygen produced carbon dioxide, methane, carbon monoxide, picoline, and formic acid as the major products. The ratio of the products was affected by the water concentration and acidity of the mixture. Increased water concentration caused a decrease in methane and an increase in carbon monoxide. Decreased acidity resulted in an increase in methane and a decrease in carbon monoxide. Isotopic labeling experiments showed that some of the carbon monoxide originated as the carboxyl group of the acetic acid. Labeling experiments also showed that formaldehyde and formic acid could be converted to carbon monoxide under the reaction conditions. Two pathways leading to the formation of carbon monoxide were proposed; one involving the decomposition of glyoxylic acid and another involving the oxidation of the methyl radical by cobalt(III). PMID:20397646

Sumner, Charles E; Little, James; Howard, Adam S; Liang, Weimin C

2010-05-17

199

Synthesis of Modified Poly(vinyl acetate) Adhesives  

Microsoft Academic Search

Modified poly(vinyl acetate) copolymers with drying oils as comonomers have been prepared. The unsaturated triglycerides can produce cross-linking and give a waterproof effect due to their hydrophobicity. The new copolymers synthesized by solution polymerization in an organic medium have been submitted to analytical characterization in order to investigate the role of the drying oils in the polymerization reaction. NMR spectroscopy

A. Salvini; L. M. Saija; M. Lugli; G. Cipriani; C. Giannelli

2010-01-01

200

Miscibility Between Ethylene Vinyl Acetate Copolymers and Tackifier Resins  

Microsoft Academic Search

A series of ethylene vinyl acetate copolymer (EVA) were blended with various kinds of tackifiers and the miscibility between the components was investigated. The miscibility of the blend is illustrated as a phase diagram. The EVA and modified rosin systems tended to have a phase diagram with lower critical solution temperature (LCST), whereas the EVA and petroleum resin systems tended

Mototsugu Takemoto; Takuma Karasawa; Hiroshi Mizumachi; Mikio Kajiyama

2000-01-01

201

Combined Input-Crosspoint Buffered Packet Switch with Flexible Access to Crosspoints Buffers  

E-print Network

1 Combined Input-Crosspoint Buffered Packet Switch with Flexible Access to Crosspoints Buffers by the adopted switch architecture. Combined input- crosspoint buffered (CICB) packet switches are being must be proportional to the number of ports and crosspoint buffer size, which is set by the distance

Rojas-Cessa, Roberto

202

Floor Buffer Guidelines Floor buffers can expose employees to noise, hazardous materials, and hazards related to  

E-print Network

Floor Buffer Guidelines Floor buffers can expose employees to noise, hazardous materials of asbestos fibers. 7. Do not operate a floor buffer with an abrasive pad on un-waxed or unfinished floors ppm while employees were operating buffers. No specific precautions are recommended. Carbon Monoxide

de Lijser, Peter

203

USDA Forest Service Gen. Tech. Rep. PSW-GTR-168. 1998. 71 Buffering the Buffer1  

E-print Network

USDA Forest Service Gen. Tech. Rep. PSW-GTR-168. 1998. 71 Buffering the Buffer1 Leslie M. Reid2 and Sue Hilton3 Abstract:Abstract:Abstract:Abstract:Abstract: Riparian buffer strips are a widely accepted in forested areas, but controversy persists over how wide a buffer strip is necessary. The physical integrity

Standiford, Richard B.

204

Multi-objective Buffer Allocation Cruz, van Woensel & Smith Buffer and throughput trade-offs in  

E-print Network

Multi-objective Buffer Allocation Cruz, van Woensel & Smith Buffer and throughput trade-offs in M. For example, one conflicting pair of objectives includes first minimizing the overall number of buffers and then maximizing throughput. In this paper, we present an original methodology to solve a buffer alloca- tion

Cruz, Frederico

205

An Time Algorithm for Optimal Buffer Insertion with b Buffer Types *  

E-print Network

An Time Algorithm for Optimal Buffer Insertion with b Buffer Types * Zhuo Dept. of Electrical Engineering Texas University College Station,Texas 77843,USA. zhuoli@ee.tamu.edu Abstract Buffer insertion is apopular technique to reduce the in- terconnect delay. The classic buffer insertion algorithm of van has

Paris-Sud XI, Université de

206

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 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

207

Networks, Buffer Allocation Problem typeset May 18, 2004 Smith & Cruz The Buffer Allocation Problem for  

E-print Network

Networks, Buffer Allocation Problem typeset May 18, 2004 Smith & Cruz The Buffer Allocation Problem for General Finite Buffer Queueing Networks J. MacGregor Smith F. R. B. Cruz e-mail: jmsmith@ecs.umass.edu e-mail: fcruz@ufmg.br May 18, 2004 Abstract -- The Buffer Allocation Problem (BAP) is a difficult stochastic

Cruz, Frederico

208

A New Stack Buffer Overflow Hacking Defense Technique with Memory Address Confirmation  

Microsoft Academic Search

Stack buffer overflow hacking became generally known due to the Morris’ Internet Worm in 1988. Since then buffer overflow\\u000a hacking has been used to attack systems and servers by hackers very frequently. Recently, many researches tried to prevent\\u000a it, and several solutions were developed such as Libsafe and StackGuard; however, these solutions have a few problems. In\\u000a this paper we

Yang-seo Choi; Dong-il Seo; Sohn Sung-Won

2001-01-01

209

Correlation between acetic acid resistance and characteristics of PQQ-dependent ADH in acetic acid bacteria  

Microsoft Academic Search

In this study, we compared the growth properties and molecular characteristics of pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) among highly acetic acid-resistant strains of acetic acid bacteria. Ga. europaeus exhibited the highest resistance to acetic acid (10%), whereas Ga. intermedius and Acetobacter pasteurianus resisted up to 6% of acetic acid. In media with different concentrations of acetic acid, the maximal

Janja Trcek; Hirohide Toyama; Jerzy Czuba; Anna Misiewicz; Kazunobu Matsushita

2006-01-01

210

The possible role of acetate in exercise hyperemia in dog skeletal muscle  

Microsoft Academic Search

The possible role of acetate in the genesis of exercise hyperemia was studied in five series of dogs. Intraarterial infusion of an isomotic solution of sodium acetate at 0.76 ml\\/min in the dog forelimb decreased the resistance to flow through skeletal muscle by 48%, primarily by decreasing resistance to flow through small vessels. Skin lymph flow and lymph protein concentration

Robert P. Steffen; Jack E. McKenzie; Francis J. Haddy

1982-01-01

211

Buffered Communication Analysis in Distributed Multiparty Sessions  

NASA Astrophysics Data System (ADS)

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

Deniélou, Pierre-Malo; Yoshida, Nobuko

212

NMR spectroscopy reveals that RNase A is chiefly denatured in 40% acetic acid: implications for oligomer formation by 3D domain swapping.  

PubMed

Protein self-recognition is essential in many biochemical processes and its study is of fundamental interest to understand the molecular mechanism of amyloid formation. Ribonuclease A (RNase A) is a monomeric protein that may form several oligomers by 3D domain swapping of its N-terminal alpha-helix, C-terminal beta-strand, or both. RNase A oligomerization is induced by 40% acetic acid, which has been assumed to mildly unfold the protein by detaching the terminal segments and consequently facilitating intersubunit swapping, once the acetic acid is removed by lyophilization and the protein is redissolved in a benign buffer. Using UV difference, near UV circular dichroism, folding kinetics, and multidimensional heteronuclear NMR spectroscopy, the conformation of RNase A in 40% acetic acid and in 8 M urea has been characterized. These studies demonstrate that RNase A is chiefly unfolded in 40% acetic acid; it partially retains the native helices, whereas the beta-sheet is fully denatured and all X-Pro peptide bonds are predominantly in the trans conformation. Refolding occurs via an intermediate, I(N), with non-native X-Pro peptide bonds. I(N) is known to be populated during RNase A refolding following denaturation in concentrated solutions of urea or guanidinium chloride, and we find that urea- or GdmCl-denatured RNase A can oligomerize during refolding. By revealing the importance of a chiefly denaturated state and a refolding intermediate with non-native X-Pro peptide bonds, these findings revise the model for RNase A oligomerization via 3D domain swapping and have general implications for amyloid formation. PMID:20085318

López-Alonso, Jorge Pedro; Bruix, Marta; Font, Josep; Ribó, Marc; Vilanova, Maria; Jiménez, María Angeles; Santoro, Jorge; González, Carlos; Laurents, Douglas V

2010-02-10

213

Buffered banks in multiprocessor systems  

SciTech Connect

A memory design based on logical banks is analyzed for shared memory multiprocessor systems. In this design, each physical bank is replaced by a logical bank consisting of a fast register and subbanks of slower memory. The subbanks are buffered by input and output queues which substantially reduce the effective cycle time when the reference rate is below saturation. The principal contribution of this work is the development of a simple analytical model which leads to scaling relationships among the efficiency, the bank cycle time, the number of processors, the size of the buffers, and the granularity of the banks. These scaling relationships imply that if the interconnection network has sufficient bandwidth to support efficient access using high-speed memory, then lower-speed memory can be substituted with little additional interconnection cost. The scaling relationships are shown to hold for a full datapath vector simulation based on the Cray Y-MP architecture. The model is used to develop design criteria for a system which supports 192 independent reference streams, and the performance of this system is evaluated by simulation over a range of loading conditions. 22 refs.

Robbins, K.A.; Robbins, S. [Univ. of Texas, San Antonio, TX (United States)] [Univ. of Texas, San Antonio, TX (United States)

1995-04-01

214

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

215

Regeneration of Cellulose Acetate Membranes.  

National Technical Information Service (NTIS)

Several simple methods for in situ one-step regeneration of both flux and salt-retention properties of service-deteriorated membranes have been developed. Membranes have been successfully regenerated using hot, 4% acetic acid, and a one-step cleaning meth...

P. A. Cantor, W. S. Higley, C. W. Saltonstall

1970-01-01

216

BiN: A Buffer-in-NUCA Scheme for Accelerator-Rich CMPs As the number of on-chip accelerators grows rapidly to improve  

E-print Network

BiN: A Buffer-in-NUCA Scheme for Accelerator-Rich CMPs ABSTRACT As the number of on-chip accelerators grows rapidly to improve power-efficiency, the buffer size required by accelerators drastically increases. Existing solutions allow the accelerators to share a common pool of buffers or/and allocate

Cong, Jason "Jingsheng"

217

The use of static and dynamic physical property measurements to infer structural properties of associated liquids: Acetic acid–water  

Microsoft Academic Search

The anomalies which occur in most static and dynamic physical property measurements on solutions of water in acetic acid can be used with critical analysis to infer associative molecular structures. The anomalies indicate significant structural changes. Proton magnetic resonance chemical shifts for acetic acid–water solutions show a significant structural change occurring in the region of equal molar concentration. Literature values

Robert W. Sims; M. Robert Willicott III; R. R. Inners

1979-01-01

218

The use of static and dynamic physical property measurements to infer structural properties of associated liquids: Acetic acid-water  

Microsoft Academic Search

The anomalies which occur in most static and dynamic physical property measurements on solutions of water in acetic acid can be used with critical analysis to infer associative molecular structures. The anomalies indicate significant structural changes. Proton magnetic resonance chemical shifts for acetic acid-water solutions show a significant structural change occurring in the region of equal molar concentration. Literature values

Robert W. Sims; M. Robert Willicott III; R. R. Inners

1979-01-01

219

Antiparasitic effect of calcium and magnesium ion-free buffer treatments against a common monogenean Neobenedenia girellae.  

PubMed

This study investigated a new effective method for controlling the capsalid monogenean Neobenedenia girellae. We examined in vitro and in vivo the effect on the percentage survival of N. girellae in buffers containing different metallic ions. Decreased survival was observed in buffer solutions lacking two ions. In particular, the percentage survival of N. girellae was significantly decreased after 10 min exposure to buffer containing neither Ca(2+) nor Mg(2+). Transmission electron microscopic observations showed that treatment with this buffer disrupted intercellular junctions. This significant effect on percentage survival of N. girellae using Ca(2+)/Mg(2+)-free buffer was confirmed in an in vivo assay. Ca(2+)/Mg(2+)-free buffer had no effect on the condition of the host, spotted halibut Verasper variegates (Pleuronectidae). These results suggest that treatment with Ca(2+)/Mg(2+)-free buffer is a new effective control method, which could replace existing control methods. PMID:17032471

Ohashi, H; Umeda, N; Hirazawa, N; Ozaki, Y; Miura, C; Miura, T

2007-02-01

220

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.; Alvarez-Sanchez, Nuria; Rodriguez-Rodriguez, Ana; Guerrero, Juan M.

2013-01-01

221

Buffer strips in composites at elevated temperature  

NASA Technical Reports Server (NTRS)

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

Bigelow, C. A.

1983-01-01

222

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."

223

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

224

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

Microsoft Academic Search

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

Y. Ohya; H. Saiki; Y. Takahashi

1994-01-01

225

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

226

21 CFR 184.1721 - Sodium acetate.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

227

21 CFR 184.1721 - Sodium acetate.  

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

2014-04-01

228

21 CFR 184.1721 - Sodium acetate.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

229

21 CFR 184.1721 - Sodium acetate.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

230

21 CFR 184.1721 - Sodium acetate.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

231

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.

2013-06-12

232

Determination of gallium at trace levels using a spectrofluorimetric method in synthetic U-Ga and Ga-As solutions  

NASA Astrophysics Data System (ADS)

A simple, easy to use and selective spectrofluorimetric method for the determination of trace levels of gallium has been developed. A new Schiff base, N-o-vanillidine-2-amino-p-cresol (OVAC) was synthesized and its fluorescence activity with gallium investigated. Based on this chelation reaction, a spectrofluorimetric method has been developed for the determination of gallium in synthetically prepared Ga-U and Ga-As samples buffered at pH 4.0 using acetic acid-sodium acetate. The chelation reaction between Ga(III) and N-o-vanillidine-2-amino-p-cresol was very fast, requiring only 30 min at room temperature to complex completely. The limit of detection (LOD) (3 ?) for Ga(III) was 7.17 nM (0.50 ?g L -1), determined from the analysis of 11 different solutions of 20 ?g L -1 Ga(III).

Kara, Derya; Fisher, Andrew; Foulkes, Mike; Hill, Steve J.

2010-01-01

233

Buffer Management Simulation in ATM Networks  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

234

African American College Women's Suicide Buffers.  

ERIC Educational Resources Information Center

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

Marion, Michelle S.; Range, Lillian M.

2003-01-01

235

DIETHANOLAMINE-CARBON DIOXIDE BUFFER PRODUCES ETHYLENE  

EPA Science Inventory

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

236

UNDERSTANDING, DERIVING, AND COMPUTING BUFFER CAPACITY  

EPA Science Inventory

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

237

Buffer Management in a Packet Switch  

Microsoft Academic Search

Consider a single packet switch with a finite number of packet buffers shared between several output queues. An arriving packet is lost if no free buffer is available, as in the CIGALE network. It has been observed by simulation that if load increases too much, congestion may occur, i.e., throughput declines; it appears that the busiest link's queue tends to

MAREK I. IRLAND

1978-01-01

238

46 CFR 58.25-45 - Buffers.  

Code of Federal Regulations, 2012 CFR

... Shipping 2 2012-10-01 2012-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST...MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great...

2012-10-01

239

AUTOMATIC TRANSFER LINES WITH BUFFER STOCKS  

Microsoft Academic Search

The efficiency of an automatic transfer line can be increased by dividing the line into a number of stages and providing buffer stores between the stages.The results of a theoretical study of the effect of buffer stocks on automatic fixed cycle in line transfer machines are reported. It is shown how the improvement in efficiency depends on the number of

J. A. BUZACOTT

1967-01-01

240

46 CFR 58.25-45 - Buffers.  

Code of Federal Regulations, 2011 CFR

... Shipping 2 2011-10-01 2011-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST...MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great...

2011-10-01

241

46 CFR 58.25-45 - Buffers.  

Code of Federal Regulations, 2010 CFR

... Shipping 2 2010-10-01 2010-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST...MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great...

2010-10-01

242

Statically Detecting Likely Buffer Overflow Vulnerabilities  

Microsoft Academic Search

Buffer overflow attacks may be today's single most important security threat. This paper presents a new approach to mitigating buffer overflow vulnerabilities by detecting likely vulnerabilities through an analysis of the program source code. Our approach exploits information provided in semantic comments and uses lightweight and efficient static analyses. This paper describes an implementation of our approach that extends the

David Larochelle; David Evans

2001-01-01

243

Buffer insertion for noise and delay optimization  

Microsoft Academic Search

Buffer insertion has successfully been applied to reduce delay in global interconnect paths; however, existing techniques only optimize delay and timing slack. With the increasing ratio of coupling to total capacitance and the use of aggressive dynamic logic circuit families, noise is becoming a major design bottleneck. We present comprehensive buffer insertion techniques for noise and delay optimization. Our experiments

Charles J. Alpert; Anirudh Devgan; Stephen T. Quay

1998-01-01

244

FIFO Buffer for Asynchronous Data Streams  

NASA Technical Reports Server (NTRS)

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

Bascle, K. P.

1985-01-01

245

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

246

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

247

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

248

Hardware Loop Buffering Scott DiPasquale  

E-print Network

Hardware Loop Buffering Scott DiPasquale Khaled Elmeleegy C.J. Ganier Erik Swanson #12;Problem and Hypothesis n Compilers have more information about loops that they can exploit. n Hardware loop unrolling is highly complex. n Buffering loops reduces instruction count and improves performance with moderate

Rixner, Scott

249

Reconciling Buffer Management with Persistence Optimisations  

E-print Network

'. Object pinning conflicts with the buffer manager's freedom to evict objects from the buffer when, to minimise pinning vs object management conflicts. Optimisation of the write barrier additionally requires management and executing code in the presence of these optimisations and aims to show that collaboration

Hosking, Antony

250

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

251

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

252

Conductance of HCl, NaCl, Na acetate, and acetic acid in water-ethylene carbonate solvent mixtures at 25 and 40°C  

Microsoft Academic Search

The molar conductances of solutions of hydrochloric acid, sodium chloride, sodium acetate, and acetic acid were measured in water-ethylene carbonate (EC) solvent mixtures at 25 and 40°C. These solvents have dielectric constants higher than that of water. Four solvent compositions, in which the mole fraction (x2) of EC was 0.2, 0.4, 0.5, and 0.6, were studied at 25°C. For HCl

Barry R. Boerner; Roger G. Bates

1978-01-01

253

Giant liposomes in physiological buffer using electroformation in a flow chamber  

E-print Network

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

Mayer, Michael

254

RNA ISOLATION 1/2 BUFFERS AND SOLUTIONS  

E-print Network

of culture when working with slow growing or flocculating cells. Place on ice immediately, keep cold-20 ml of a 50 ml culture to 30-40 ml of ice-cold water (in 50 ml Falcontube). Use larger volume of ice-cold water and transfer to a 2 ml Eppendorf tube (preferably safe-lock or screw-cap tube). #12;RNA

255

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

256

Optimal Buffer Size for Wireless Mesh Networks! INTRODUCTION!  

E-print Network

Optimal Buffer Size for Wireless Mesh Networks! INTRODUCTION! Buffers are used to absorb transient traffic bursts. Very large buffers, which are common nowadays, lead to long queuing delays. On the other hand, very small buffers may result in network under-utilization. Our goal is to determine buffer size

Chaudhuri, Surajit

257

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

258

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

259

Effects of phosphate buffer in parenteral drugs on particle formation from glass vials.  

PubMed

The characteristics of inorganic particles generated in glass vials filled with phosphate buffer solutions were investigated. During storage, particles were visually detected in the phosphate buffer solution in particular glass vials which pass compendial tests of containers for injectable drugs. These particles were considered to be different from ordinal glass delamination, which has been reported in a number of papers because the particles were mainly composed of Al, P and O, but not Si. The formation of the particles accelerated at higher storage temperatures. Among the surface treatments tested for the glass vials, sulfur treatment showed a protective effect on the particle formation in the vials, whereas the SiO(2) coating did not have any protective effects. It was found that the elution ratio of Al and Si in the solution stored in the glass vials after the heating was similar to the ratio of Al and Si in borosilicate glass. However, the Al concentration decreased during storage (5°C, 6 months), and consequently, particle formation was observed in the solution. Adding citrate, which is a chelating agent for Al, effectively suppressed the particle formation in the heated solution. When 50 ppb and higher concentrations of Al ion were added to the phosphate buffer solution, the formation of white particles containing Al, P and O was detected. It is suggested that a phosphate buffer solution in a borosilicate glass vial has the ability to form particles due to interactions with the Al that is eluted from the glass during storage. PMID:23420583

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

2013-01-01

260

Thin La{sub 2}Zr{sub 2}O{sub 7} films made from a water-based solution  

SciTech Connect

Thin films of La{sub 2}Zr{sub 2}O{sub 7} (LZO) are highly regarded as possible buffer layers in the coated conductor configuration. This report describes a new synthesis for thin crystalline LZO films, based on a largely water-based solution, mainly containing metal acetates, acetic acid and an organic amine-base: triethanolamine. Initially, a thin layer of amorphous material is deposited on the textured Ni-5 at%W substrate by means of dip-coating. Only by careful control of the thermal treatment can the layer be transformed into a crystalline layer. Important parameters in this respect are the heating rate and the dwell time. The amorphous gel is analysed by HR-TGA/DTA and HR-TEM. The textured layers are analysed by XRD, pole figures, RHEED, AFM and SEM. - Grapical Abstract: Thin films of La2Zr2O7 (LZO) are produced via a water-based solution, containing metal acetates, acetic acid and triethanolamine. The thin layer is deposited on the textured Ni-5 at%W substrate by dip-coating. The amorphous gel is analysed by HR-TGA/DTA and HR-TEM. The textured layers are analysed by XRD, pole figures, RHEED analysis, AFM and SEM.

Cloet, V. [Ghent University, Krijgslaan 281-S3, 9000 Gent (Belgium)], E-mail: veerle.cloet@ugent.be; Feys, J. [Ghent University, Krijgslaan 281-S3, 9000 Gent (Belgium); Huehne, R. [Institute for Metallic Materials, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden (Germany); Hoste, S.; Van Driessche, I. [Ghent University, Krijgslaan 281-S3, 9000 Gent (Belgium)

2009-01-15

261

pKa of acetate in water: a computational study.  

PubMed

Several computational methods including the conductor-like polarizable continuum model, CPCM with both UAKS and UAHF cavities, Cramer and Truhlar's generalized Born solvation model, SM5.4(AM1), SM5.4(PM3), and SM5.43R(mPW1PW91/6-31+G(d)), and mixed QM/MM-Ewald simulations were used to calculate the pK(a) values of acetate and bicarbonate anions in aqueous solution. This work provided a critical and comprehensive assessment of the quality of these theoretical models in the calculation of aqueous solvation free energies for the singly charged acetate and bicarbonate ions, as well as the doubly charged acetate dianion and carbonate dianion. It was shown that QM/MM-Ewald simulations could give an accurate and consistent evaluation of the pK(a) values of acetate and bicarbonate based on both the relative and absolute pK(a) formulas, while other methods could yield satisfactory results only for certain calculations. However, this does not mean that the current QM/MM-Ewald protocol is superior to other methods. The useful information obtained in this investigation is that both the absolute and relative pK(a) formulas should better be tested in accurate calculations of pK(a) values based on any methods. PMID:16863127

Gao, Daqing; Svoronos, Paris; Wong, Peter K; Maddalena, Deborah; Hwang, Junwoong; Walker, Hughton

2005-12-01

262

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 ...

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

2000-01-01

263

How Might New Neurons Buffer Against Stress?  

MedlinePLUS

How Might New Neurons Buffer Against Stress? Recent News Rapid Mood Lifter First Jump-starts Pleasure-seeking October 17, 2014 Groundbreaking ... Risks Rise Early in Psychosis October 8, 2014 New US Clinical Data on Mental Disorders October 8, ...

264

A MICROPROCESSOR ASCII CHARACTER BUFFERING SYSTEM  

EPA Science Inventory

A microprocessor buffering system (MBS) was developed at the Environmental Monitoring and Support Laboratory -Cincinnati (EMSL-CI) to provide an efficient transfer for serial ASCII information between intelligent instrument systema and a Data General NOVA laboratory automation co...

265

Soil Formation & Retention Stores and buffers  

E-print Network

Soil Formation & Retention· Stores and buffers soil nutrients · Stores water · Drives soil ecosystem #12;Flood control · Water filtration, retention and flow · Protection from tsunamis and hurricanes

Gottgens, Hans

266

Probabilistic Analysis of Buffer Starvation in Markovian Queues  

E-print Network

Our purpose in this paper is to obtain the exact distribution of the number of buffer starvations within a sequence of $N$ consecutive packet arrivals. The buffer is modeled as an M/M/1 queue, plus the consideration of bursty arrivals characterized by an interrupted Poisson process. When the buffer is empty, the service restarts after a certain amount of packets are prefetched. With this goal, we propose two approaches, one of which is based on Ballot theorem, and the other uses recursive equations. The Ballot theorem approach gives an explicit solution, but at the cost of the high complexity order in certain circumstances. The recursive approach, though not offering an explicit result, needs fewer computations. We further propose a fluid analysis of starvation probability on the file level, given the distribution of file size and the traffic intensity. The starvation probabilities of this paper have many potential applications. We apply them to optimize the quality of experience (QoE) of media streaming serv...

Xu, Yuedong; El-Azouzi, Rachid; Haddad, Majed; Elayoubi, Salaheddine; Jimenez, Tania

2011-01-01

267

Buffer assignment algorithms for data driven architectures  

E-print Network

BUFFER ASSIGNMENT ALGORITHMS FOR DATA DRIVEN ARCHITECTURES A Thesis by MITRA JIT CHATTERJEE Submitted to the OIIIce of Graduate Studies of Texas ASM University in partial ful611ment of the requirements for the degree of MASTER OF SCIENCE... August 1994 Major Subject: Computer Science BUFFER ASSIGNMENT ALGORITHMS FOR DATA DRIVEN ARCHITECTURES A Thesis by MITRAJIT CHATTERJEE Submitted to Texas ARM University in partial fulfillment of the requirements for the degree of MASTER...

Chatterjee, Mitrajit

2012-06-07

268

Frog striated muscle is permeable to hydroxide and buffer anions.  

PubMed

Hydroxide, bicarbonate and buffer anion permeabilities in semitendinosus muscle fibers of Rana pipiens were measured. In all experiments, the fibers were initially equilibrated in isotonic, high K2SO4 solutions at pHo = 7.2 buffered with phosphate. Two different methods were used to estimate permeabilities: (i) membrane potential changes were recorded in response to changes in external ion concentrations, and (ii) intracellular pH changes were recorded in response to changes in external concentrations of ions that alter intracellular pH. Constant field equations were used to calculate relative or absolute permeabilities. In the first method, to increase the size of the membrane potential change produced by a sudden change in anion entry, external K+ was replaced by Cs+ prior to changes of the anion under study. At constant external Cs+ activity, a hyperpolarization results from increasing external pH from 7.2 to 10.0 or higher, using either CAPS (3-[cyclohexylamino]-1-propanesulfonic acid) or CHES (2-[N-cyclohexylamino]-ethanesulfonic acid) as buffer. For each buffer, the protonated form is a zwitterion of zero net charge and the nonprotonated form is an anion. Using reported values of H+ permeability, calculations show that the reduction in [H+]o cannot account for the hyperpolarizations produced by alkaline solutions. Membrane hyperpolarization increases with increasing total external buffer concentration at constant external pH, and with increasing external pH at constant external buffer anion concentration. Taken together, these observations indicate that both OH- and buffer anions permeate the surface membrane. The following relative permeabilities were obtained at pHo = 10.0 +/- 0.3: (POH/PK) = 890 +/- 150, (PCAPS/PK) = 12 +/- 2, (PCHES/PK) = 5.3 +/- 0.9, and (PNO3/PK) = 4.7 +/- 0.5. PNO3/PK was independent of pHo up to 10.75. At pHo = 9.6, (PHCO3/PK) = 0.49 +/- 0.03; at pHo = 8.9, (PCl/PK) = 18 +/- 2 and at pHo = 7.1, (PHEPES/PK) = 20 +/- 2. In the second method, on increasing external pH from 7.2 to 10.0, using 2.5 mM CAPS (total buffer concentration), the internal pH increases linearly with time over the next 10 min. This alkalinization is due to the entry of OH- and the absorption of internal H+ by entering CAPS- anion. The rate of CAPS- entry was determined in experiments in which the external CAPS concentration was increased at constant external pH. Such increases invariably produced an increase in the rate of internal alkalinization, which was reversed when the CAPS concentration was reduced to its initial value.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8071988

Venosa, R A; Kotsias, B A; Horowicz, P

1994-04-01

269

Buffer regulation of calcium puff sequences  

NASA Astrophysics Data System (ADS)

Puffs are localized Ca2 + signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP3). They are the result of the liberation of Ca2 + from the endoplasmic reticulum through the coordinated opening of IP3 receptor/channels clustered at a functional release site. The presence of buffers that trap Ca2 + provides a mechanism that enriches the spatio-temporal dynamics of cytosolic calcium. The expression of different types of buffers along the cell's life provides a tool with which Ca2 + signals and their responses can be modulated. In this paper we extend the stochastic model of a cluster of IP3R-Ca2 + channels introduced previously to elucidate the effect of buffers on sequences of puffs at the same release site. We obtain analytically the probability laws of the interpuff time and of the number of channels that participate of the puffs. Furthermore, we show that under typical experimental conditions the effect of buffers can be accounted for in terms of a simple inhibiting function. Hence, by exploring different inhibiting functions we are able to study the effect of a variety of buffers on the puff size and interpuff time distributions. We find the somewhat counter-intuitive result that the addition of a fast Ca2 + buffer can increase the average number of channels that participate of a puff.

Fraiman, Daniel; Ponce Dawson, Silvina

2014-02-01

270

7—STUDIES ON THE SORPTION OF MOISTURE BY POLYMERS PART III—CELLULOSE ACETATE AND CELLULOSE TRIACETATE FIBRES  

Microsoft Academic Search

The adsorption isotherms of water vapour on a wide range of commercial secondary cellulose acetate and cellulose triacetate fibres have been measured at 22°C. Conversion of cellulose acetate flake into fibres causes a drop in sorption, but otherwise the sorption is almost unaffected by the filament denier, conversion into staple fibres, solution-dyeing, or delustrant. Stretchspinning, as in the production of

D. K. Beever; L. Valentine

1958-01-01

271

Metabolism of steroid acetates by Streptomyces albus.  

PubMed

Fermentation of 16-dehydropregnenolone acetate (1a) with Streptomyces albus yielded 16-dehydropregnenolone (1b) and 16-dehydroprogesterone (IIa). Similar incubation of pregnenolone acetate (Ic) with the strain afforded pregnenolone (Id), progesterone (IIb) and 20 alpha-hydroxy progesterone (IIc) while dehydroepiandrosterone acetate (IIIa) under the conditions was converted to dehydroepiandrosterone (IIIb), androstenedione (IVa) and testosterone (IVc). The strain was also capable of converting testosterone acetate (IVb) having the 17-acetoxy function in the 5-membered D-ring to testosterone (IVc) and androstenedione (IVa). All the products were identified by the application of various chemical and spectrometric techniques. PMID:6708550

Mukherjee, A; Mahato, S B

1984-03-01

272

Fluorescent labeling of drugs and simple organic compounds containing amine functional groups, utilizing dansyl chloride in Na(2)CO(3) buffer.  

PubMed

Fluorescent labeling of amine functional groups using dansyl chloride (DNS-Cl), and in sodium carbonate buffer, allowed the detection of 1 microg amounts of analytes. The methodology presented allows dansylation of primary, secondary, and tertiary amine groups at a temperature of 25 degrees C. The dansylation of tertiary amines involves a chemical reaction which removes one substituent (or branch) of the amine group. A one molar working concentration of Na(2)CO(3) is used, and is at pH 11.0. Compounds such as isopropylamine, dipropylamine, diethylamine, triethylamine, triisooctylamine, and N,N-dimethylaniline were labeled by use of DNS-Cl from samples obtained from a complex mixture of alkanes. The compound p-chloroaniline contains a primary amine group and is a solid at 25 degrees, quickly dissolves in the one molar sodium carbonate buffer and is dansylated in 15 min. Heroin, which contains a tertiary amine group, was extracted into ethyl acetate from an aqueous solution, then reacted with DNS-Cl. Benzocaine, a local anesthetic, was dansylated in 15 min. Tertiary amine groups incorporated in a rigid ring system, such as for caffeine, strychnine, and the ionic salt form of cocaine hydrochloride did not react with DNS-Cl under these conditions. The reaction time for tertiary amines was 2 h or less, and 15 min for compounds having primary and secondary amine groups. Separation of the dansylated compounds from unreacted DNS-Cl was accomplished by diethyl ether extraction of the aqueous reaction solution, followed by thin layer chromatography using various organic solvents such as acetone and methylene chloride. PMID:11755390

Bartzatt, R

2001-01-01

273

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

274

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

275

Oxygen17 and proton nuclear magnetic resonance studies on acetic acid exchange processes of the chloride, nitrate, and acetate of nickel(II) in acetic acid  

Microsoft Academic Search

The exchange rates of acetic acid coordinating to nickel(II) chloride, nickel(II) nitrate, and nickel(II) acetate in neat acetic acid and acetic acid\\/dichloromethane-d2 mixtures were measured by the oxygen-17 and proton NMR line-broadening methods. The activation parameters for the acetic acid exchange on these nickel(II) salts were independent of the concentration of acetic acid (HOAc) in the mixed solvents. The first-order

A. Hioki; S. Funahashi; M. Tanaka

1985-01-01

276

UVB photolysis of hydrocortisone 21-acetate.  

PubMed

Hydrocortisone 21-acetate (HCA) in methanol solution undergoes photodegradation under UVB light, as monitored by HPLC. Five main photoproducts have been isolated and characterized by means of NMR and mass spectroscopy. One of them derives from a Norrish I photoreaction which cleaves the C17-C20 bond of the steroid yielding the andro-derivative, a second product comes from a Yang-type photorearrangement which links C18 to C20 yielding a cyclobutane adduct. The former photoproduct, in turn, undergoes further photolysis giving rise to various photoproducts, of which three have been characterized. The first is a stereoisomer of the andro-derivative, the others arise from the opening of the five-membered ring. HCA also proved photounstable in the solid state and in a commercial formulation for topical use, thus confirming the requirements of the Pharmacopeias for light protection of this drug. Indeed, experiments on LPS-stimulated THP-1 cells demonstrated the loss of anti-inflammatory activity when HCA was UVB-photodegraded. The radical mechanism involved in HCA photolysis seems also responsible for the in vitro photohemolytic effect and lipid peroxidation induced by HCA in combination with UVB light. PMID:18423938

Caffieri, Sergio; Dall'Acqua, Stefano; Castagliuolo, Ignazio; Brun, Paola; Miolo, Giorgia

2008-08-01

277

Biodegradable Plastics Based on Cellulose Acetate  

Microsoft Academic Search

It is generally known that secondary cellulose acetate (with 53 to 56% acetyl groups) is suitable for thermoplastic processing. With appropriate plasticizers a plastic material is obtained which excels in transparency and pleasant texture, and it is therefore often used for tool handles, combs, spectacle frames, and the like. In principle, cellulose acetate with such a degree of substitution is

Alexander Ach

1993-01-01

278

21 CFR 582.1005 - Acetic acid.  

Code of Federal Regulations, 2012 CFR

21 Food and Drugs 6 2012-04-01...2012-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2012-04-01

279

21 CFR 582.1005 - Acetic acid.  

Code of Federal Regulations, 2013 CFR

21 Food and Drugs 6 2013-04-01...2013-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2013-04-01

280

21 CFR 582.1005 - Acetic acid.  

Code of Federal Regulations, 2011 CFR

21 Food and Drugs 6 2011-04-01...2011-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2011-04-01

281

21 CFR 582.1005 - Acetic acid.  

Code of Federal Regulations, 2010 CFR

21 Food and Drugs 6 2010-04-01...2010-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2010-04-01

282

21 CFR 582.1005 - Acetic acid.  

21 Food and Drugs 6 2014-04-01...2014-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2014-04-01

283

Manufacturing Ethyl Acetate From Fermentation Ethanol  

NASA Technical Reports Server (NTRS)

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

Rohatgi, Naresh K.; Ingham, John D.

1991-01-01

284

21 CFR 522.960b - Flumethasone acetate solution.  

...adjusted according to the weight of the animal, the severity of the symptoms...injection should not exceed 3 days of therapy. With chronic conditions intramuscular...of from 0.0625 to 0.25 mg per animal. (2) Indications for...

2014-04-01

285

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

286

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

287

Distributed Utility-Optimal Scheduling with Finite Buffers  

E-print Network

Distributed Utility-Optimal Scheduling with Finite Buffers Dongyue Xue, Robert Murawski, Eylem algorithm for networks with single-hop transmissions that can guarantee finite buffer sizes and meet minimum with a tradeoff in the buffer sizes. The finite buffer property is not only important from an implementation

Paris-Sud XI, Université de

288

Buffered Resource Constraint: Algorithms and Christian Bessiere1  

E-print Network

Buffered Resource Constraint: Algorithms and Complexity Christian Bessiere1 , Emmanuel Hebrard2.walsh@nicta.com.au Abstract. The notion of buffered resource is useful in many problems. A buffer contains a finite set of items required by some activities, and changing the content of the buffer is costly. For instance

Paris-Sud XI, Université de

289

Fast Algorithms For Slew Constrained Minimum Cost Buffering  

E-print Network

Fast Algorithms For Slew Constrained Minimum Cost Buffering Shiyan Hu, Charles J. Alpert , Jiang demand for buffer- ing resources. This problem requires ultra-fast buffering techniques to handle large volume of nets, while also min- imizing buffering cost. This problem is intensively studied in this paper

Hu, Jiang

290

Formal But Lively Buffers in TLA+ Peter B. Ladkin  

E-print Network

Formal But Lively Buffers in TLA+ Peter B. Ladkin omitted. We specify in TLA a buffer implemented as an array, a dou- ble buffer implemented as two arrays in series, and an abstract buffer which uses a sequence. We prove, formally and rigorously

Ladkin, Peter B.

291

Formal But Lively Buffers in TLA + Peter B. Ladkin  

E-print Network

Formal But Lively Buffers in TLA + Peter B. Ladkin Universit¨at Bielefeld, Technische Fakult­ stood, our example needs only the trivial invariant, which is simply omitted. We specify in TLA a buffer implemented as an array, a dou­ ble buffer implemented as two arrays in series, and an abstract buffer which

Ladkin, Peter B.

292

Optimal buffer control during congestion in an ATM network node *  

E-print Network

Optimal buffer control during congestion in an ATM network node * Leandros Tassiulas Yaochung Hung the number of cells to be st,ored in the buffer exceeds the available buffer space, ccriaiii cells havea.y be dropped after they are already in the buffer. Ilel~endingon the control that we have

Panwar, Shivendra S.

293

Scheduling in Switches with Small Internal Buffers: Extended Version  

E-print Network

Scheduling in Switches with Small Internal Buffers: Extended Version Nikos Chrysos and Manolis://archvlsi.ics.forth.gr/bpbenes/ Abstract-- Unbuffered crossbars or switching fabrics contain no internal buffers, and function using only, during each time slot. Buffered crossbars, on the other hand, contain sufficient internal buffering (N2

Katevenis, Manolis G.H.

294

Small-Buffer Networks Mark Shifrin, Isaac Keslassy  

E-print Network

Small-Buffer Networks Mark Shifrin, Isaac Keslassy Department of Electrical Engineering, Technion buffers, which significantly increase their power consumption and design time. Re- cent models of large-buffer networks have suggested that these large buffers could be replaced with much smaller ones. Unfortunately

Keslassy, Isaac

295

Buffer sizing in 802.11 Wireless Mesh Networks  

E-print Network

Buffer sizing in 802.11 Wireless Mesh Networks Electrical Engineering Day Basem Shihada #12 `Bufferbloat' Large FTP 2 #12;Impact of large buffers · TCP cwnd grows to fill available (large) buffers ­ Impacts TCP stability ­ Increases queueing delays for other flows sharing the buffer 3 #12;Problem

Shihada, Basem

296

Distributed scheduling based on due dates and buffer prioritization  

Microsoft Academic Search

The problem of scheduling a semiconductor manufacturing facility is addressed. Several buffer priority and due-date based scheduling policies for nonacyclic flow lines are studied. Not all buffer priority policies are stable, as is shown by a counterexample. However, the first buffer first serve and last buffer first serve policies are stable. Also, the earliest due data and least-slack policies are

C.-H. Lu; P. R. Kumar

1990-01-01

297

Buffer overflow bounds for multiplexed regulated traffic streams F. Guillemina  

E-print Network

1 Buffer overflow bounds for multiplexed regulated traffic streams F. Guillemina , N. Likhanovb , R in a common buffer. We derive bounds on the tail of the probability distribution function of the buffer of buffer overflow in the single input case. We then consider the case when the number of sources is large

Guillemin, Fabrice

298

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

299

Improving phosphate buffer-free cathode performance of microbial fuel cell based on biological nitrification.  

PubMed

To reduce the amount of phosphate buffer currently used in Microbial Fuel Cell's (MFC's), we investigated the role of biological nitrification at the cathode in the absence of phosphate buffer. The addition of a nitrifying mixed consortia (NMC) to the cathode compartment and increasing ammonium concentration in the catholyte resulted in an increase of cell voltage from 0.3 V to 0.567 V (external resistance of 100 Omega) and a decrease of catholyte pH from 8.8 to 7.05. A large fraction of ammonium was oxidized to nitrite, as indicated by an increase of nitrate-nitrogen (NO(3)(-)-N). An MFC inoculated with an NMC and supplied with 94.2 mgN/l ammonium to the catholyte could generate a maximum power of 2.1+/-0.14 mW (10.94+/-0.73 W/m(3)). This compared favorably to an MFC supplied with either buffered or non-buffered solution. The buffer-free NMC inoculated cathodic chamber showed the smallest polarization resistance, suggesting that nitrification resulted in improved cathode performance. The improved performances of the phosphate buffer-free cathode and cell are positively related to biological nitrification, in which we suggest additional protons produced from ammonium oxidation facilitated electrochemical reduction of oxygen at cathode. PMID:19502045

You, Shi-Jie; Ren, Nan-Qi; Zhao, Qing-Liang; Kiely, Patrick D; Wang, Jing-Yuan; Yang, Feng-Lin; Fu, Lei; Peng, Luo

2009-08-15

300

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

E-print Network

Other boxcar, width, [buffer, /decimate] Boxcar smoothing clip, datamin, datamax, [buffer, /blank] Truncate spectrum to a min and max data value decimate, [nchan, startat, buffer, ok] Decimate the spectrum by paring channels gconvol, kernel, [scale_factor, buffer, ok, /normalize, /center, Convolve the spectrum

Groppi, Christopher

301

21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.  

...2014-04-01 2014-04-01 false Ethyl alcohol containing ethyl acetate. 584.200...Affirmed as GRAS § 584.200 Ethyl alcohol containing ethyl acetate. The feed additive ethyl alcohol containing ethyl acetate meets the...

2014-04-01

302

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

303

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

304

Heuristic decomposition approach to buffer operation planning in a production process  

Microsoft Academic Search

Optimal operation planning or a production process with buffers and electric power plants is considered. The problem is formulated as a mixed-integer linear program with special structure. A suboptimal solution is obtained by a heuristic decomposition procedure. The master program is solved by the dynamic programming technique, and the subproblems are solved by a greedy method. When applied to the

NOBUO SANNOMIYA; CHISAKU ONISHI; Hiroyuki Yoshino

1990-01-01

305

PS'2006 -Photonics in Switching Conference Optical Buffering and Switching for Optical Packet Switching  

E-print Network

for future optical communication networking. Optical packet switching is a highly desirable approach; however, but severely limit network performance if used as the sole solution. The architecture for the packet switchPS'2006 - Photonics in Switching Conference Optical Buffering and Switching for Optical Packet

Bowers, John

306

Neurogenetic models in modeling nonlinear digital I\\/O buffer circuits  

Microsoft Academic Search

Neural network models are used as strong interpolation tools to model digital I\\/O buffer circuits accurately. Training a neural network involves use of complex training algorithms. Optimizing a neural network is complicated due to a large number of variable parameters involved in the process. Genetic algorithms are used to optimize a problem with a very large number of possible solutions

Menas Roumbakis; B. Mutnury; S. Ulrich; J. Ratcliffe; D. de Araujo; M. Cases

2005-01-01

307

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

308

Correlation between acetic acid resistance and characteristics of PQQ-dependent ADH in acetic acid bacteria.  

PubMed

In this study, we compared the growth properties and molecular characteristics of pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) among highly acetic acid-resistant strains of acetic acid bacteria. Gluconacetobacter europaeus exhibited the highest resistance to acetic acid (10%), whereas Gluconacetobacter intermedius and Acetobacter pasteurianus resisted up to 6% of acetic acid. In media with different concentrations of acetic acid, the maximal acetic acid production rate of Ga. europaeus slowly increased, but specific growth rates decreased concomitant with increased concentration of acetic acid in medium. The lag phase of A. pasteurianus was twice and four times longer in comparison to the lag phases of Ga. europaeus and Ga. intermedius, respectively. PQQ-dependent ADH activity was twice as high in Ga. europaeus and Ga. intermedius as in A. pasteurinus. The purified enzymes showed almost the same specific activity to each other, but in the presence of acetic acid, the enzyme activity decreased faster in A. pasteurianus and Ga. intermedius than in Ga. europaeus. These results suggest that high ADH activity in the Ga. europaeus cells and high acetic acid stability of the purified enzyme represent two of the unique features that enable this species to grow and stay metabolically active at extremely high concentrations of acetic acid. PMID:16133326

Trcek, Janja; Toyama, Hirohide; Czuba, Jerzy; Misiewicz, Anna; Matsushita, Kazunobu

2006-04-01

309

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

310

Biochar contribution to soil pH buffer capacity  

NASA Astrophysics Data System (ADS)

Biochar as ecologically clean and stable form of carbon has complex of physical and chemical properties which make it a potentially powerful soil amendment (Mutezo, 2013). Therefore during the last decade the biochar application as soil amendment has been a matter for a great number of investigations. For the ecological viewpoint the trend of decreasing of soil organic matter in European agricultural land is a major problem. Society is faced with the task to find possibilities to stabilize or increase soil organic matter content in soil and quality. The availability of different functional groups (e.g. carboxylic, phenolic, acidic, alcoholic, amine, amide) allows soil organic matter to buffer over a wide range of soil pH values (Krull et al. 2004). Therefore the loss of soil organic matter also reduces cation exchange capacity resulting in lower nutrient retention (Kimetu et al. 2008). Biochar can retain elements in soil directly through the negative charge that develops on its surfaces, and this negative charge can buffer acidity in the soil. There are lack of investigations about the effect of biochar to soil pH buffering properties, The aim of our investigation was to investigate the changes in soil pH buffer capacity in a result of addition of carbonizated material to temperate region soils. In the experiment different kind of softwood biochars, activated carbon and different soil types with various organic matter and pH were used. The study soils were Albeluvisols, Leptosols, Cambisols, Regosols and Histosols . In the experiment the series of the soil: biochar mixtures with the biochar content 0 to 100% were used. The times of equiliberation between solid and liquid phase were from 1 to 168 hours. The suspension of soil: biochar mixtures was titrated with HCl solution. The titration curves were established and pH buffer capacities were calculated for the pH interval from 3.0 to 10.0. The results demonstrate the dependence of pH buffer capacity from soil type, organic matter and type of added carbonizated material. Our study showed that the biochar content has significant role in total pH buffer capacity in soil:biochar system . References. Kimetu, J.M., Lehmann, J., Ngoze, S.O., Mugendi, D.N., Kinyangi, J., Riha, S.J., Verchot, L., Recha, J.W., Pell, A.N. 2008. Reversibility of Soil Productivity Decline with Organic Matter of Differing Quality Along a Degradation Gradient. Ecosystems, 11, 726-739. Krull, E. S., Skjemstad, J.O., Baldock, J.A. 2004 'Functions of Soil Organic Matter and the Effect on Soil Properties'. GRDC report. Project CSO 00029. Mutezo, W.T., 2013. Early crop growth and yield responses of maize (Zea mays) to biochar applied on soil. International Working Paper Series, 13/03, 50 pp.

Tonutare, Tonu; Krebstein, Kadri; Utso, Maarius; Rodima, Ako; Kolli, Raimo; Shanskiy, Merrit

2014-05-01

311

Variable Packet Size Buffered Crossbar (CICQ) Switches  

E-print Network

-Packet-Size BufXbars are even better · no SAR no speedup higher line rate · no output queues lower cost w. SAR: one-iteration iSLIP, 64-byte segments #12;A VPS Buffered Crossbar Chip Design · 32x32 ports, in Verilog ­ Core only, no pads & transceivers · Fully verified: Verilog versus C++ performance simulator

Katevenis, Manolis G.H.

312

A Discovery Chemistry Experiment on Buffers  

ERIC Educational Resources Information Center

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

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

2014-01-01

313

Throughput Region of Finite-Buffered Networks  

E-print Network

the Internet, are packet switched networks. One of the main reasons behind the success of packet switched--Queuing theory, flow-controlled networks, scheduling, packet switching, buffered crossbars. Ã? 1 INTRODUCTION MOST of the current communication networks are packet switched networks. A prominent feature of packet networks

314

A Scheme of Predictor Based Stream Buffers  

E-print Network

Data Cache Misses In Superscalar � Redesign RF-Cache-DRAM memory hierarchy � Addition of L2 and L3 is a modified standard stream buffer. � A group of predictors with each predictor responsible for prediction � Implementation of PC-coupled predictors and compare with current performance. � Redesign the structure of stream

Rixner, Scott

315

Body Buffer Zone and Proxemics in Blocking.  

ERIC Educational Resources Information Center

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

Stockwell, John C.; Bahs, Clarence W.

316

Buffer Size Requirements Under Longest Queue First  

Microsoft Academic Search

A model of a switching component in a packet switching network is considered. Packetsfrom several incoming channels arrive and must be routed to the appropriate outgoingport according to a service policy. A task confronting the designer of such a system is theselection of policy and the determination of the corresponding input buffer requirementswhich will prevent packet loss. One natural choice

H. Richard Gail; George A. Grover; Roch Guérin; Sidney L. Hantler; Zvi Rosberg; Moshe Sidi

1993-01-01

317

Design and synthesis of novel isoelectric buffers  

E-print Network

made by attaching an isoelectric buffer of a welldefined pI value (such as iminodiacetic acid, IDA, aspartic acid, ASP or glutamic acid, GLU) to the PVA backbone and crosslinking the PVA strands, in situ. The pH in these membranes does not change...

Lalwani, Sanjiv Kumar Shankerdass

2006-04-12

318

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

319

Transport Parameters in a Porous Cellulose Acetate Membrane  

PubMed Central

The transport parameters of a cellulose acetate membrane prepared from a mixture of cellulose acetate, formamide, and acetone, 25:25:50 by weight, were studied. The membrane consists of a thin, porous layer, the skin, in series with a thick, highly porous layer, the coarse support. In the skin the diffusional permeability coefficient, ?, of a number of small amides and alcohols depends critically upon the partition coefficient, Ks, the size of the molecule, and the apparent hydrogen-bonding ability, Ns, of the solute. These observations are in general agreement with our earlier conclusions on the properties of nonporous membranes. On the other hand, the corrected reflection coefficient, ?', is not a very sensitive function of either Ns or Ks taken separately. The correlation between ?' and molecular diameter is reasonably good; however, it is much improved when both Ns and Ks are taken into consideration. Isotope interaction was also studied in the present preparation and was found to provide only a small (5–8%) contribution to the diffusional permeability coefficient of ethylene glycol. The contribution of solute-water friction was found to be less than 24% of the total solute friction. PMID:5410490

DiPolo, R.; Sha'afi, R. I.; Solomon, A. K.

1970-01-01

320

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

NASA Astrophysics Data System (ADS)

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

Welty, Alan

2009-07-01

321

Baroreflex buffering and susceptibility to vasoactive drugs  

NASA Technical Reports Server (NTRS)

BACKGROUND: The overall effect of vasoactive drugs on blood pressure is determined by a combination of the direct effect on vascular tone and an indirect baroreflex-mediated effect, a baroreflex buffering of blood pressure. Differences in baroreflex function affect the responsiveness to vasoactive medications, particularly baroreflex buffering of blood pressure; however, the magnitude is not known. METHODS AND RESULTS: We characterized baroreflex function and responses to vasoactive drugs in patients with idiopathic orthostatic intolerance, patients with essential hypertension, patients with monogenic hypertension and brachydactyly, patients with multiple system atrophy, and control subjects. We used phenylephrine sensitivity during ganglionic blockade as a measure of baroreflex buffering. Phenylephrine (25 microg) increased systolic blood pressure 6+/-1.6 mm Hg in control subjects, 6+/-1.1 mm Hg in orthostatic intolerance patients, 18+/-3.9 mm Hg in patients with essential hypertension, 31+/-3.4 mm Hg in patients with monogenic hypertension, and 25+/-3.4 mm Hg in patients with multiple system atrophy. Similar differences in sensitivities between groups were observed with nitroprusside. The sensitivity to vasoactive drugs was highly correlated with baroreflex buffering function and to a lesser degree with baroreflex control of heart rate. In control subjects, sensitivities to nitroprusside and phenylephrine infusions were correlated with baroreflex heart rate control and sympathetic nerve traffic. CONCLUSIONS: Our findings are consistent with an important effect of baroreflex blood pressure buffering on the sensitivity to vasoactive drugs. They suggest that even moderate changes in baroreflex function may have a substantial effect on the sensitivity to vasoactive medications.

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

2002-01-01

322

Ferroelectric thin film bismuth titanate prepared from acetate precursors  

SciTech Connect

Bismuth titanate (Bi{sub 4}Ti{sub 3}O{sub 12}) thin films were fabricated by spin coat deposition followed by rapid thermal processing (RTP). Acetate derived solutions for deposition were synthesized by blending bismuth acetate in aqueous acetic acid and then adding titanium acetate. A series of electrically insulating, semiconducting and conducting substrates were evaluated for Bi{sub 4}Ti{sub 3}O{sub 12} film deposition. While X-ray diffraction and TEM analyses indicated that the initial perovskite crystallization temperature was 500{degrees}C or less for these Bi{sub 4}Ti{sub 3}O{sub 12} films, a 700{degrees}C crystallization treatment was used to obtain single phase perovskite films. Bi{sub 4}Ti{sub 3}O{sub 12} film crystallographic orientation was shown to depend on three factors: substrate surface morphology, the number of coating layers and thermal processing. While preferred c-direction orientation was observed for Bi{sub 4}Ti{sub 3}O{sub 12} films deposited on silver foil substrates, preferred a-direction orientation was obtained for films deposited on both Si and Pt coated Si wafers. The films were dense, smooth, crack free, and had grain sizes ranging from 20 nm to 100 nm. Film thickness and refractive index were determined using a combination of ellipsometry, waveguide refractometry and TEM measurements. Both low field dielectric and ferroelectric properties were measured for an 800 nm thick film deposited on a Pt coated MgO substrate. A remanent polarization of 38 {mu}C/cm{sup 2} and a coercive field of 98 kV/cm were measured for this film that was crystallized at 700{degrees}C.

Lu, Yanxia; Hoelzer, D.T.; Schulze, W.A. [Alfred Univ., NY (United States); Tuttle, B.A.; Potter, B.G. [Sandia National Labs., Albuquerque, NM (United States)

1994-10-01

323

Acetic acid fermentation of acetobacter pasteurianus: relationship between acetic acid resistance and pellicle polysaccharide formation.  

PubMed

Acetobacter pasteurianus strains IFO3283, SKU1108, and MSU10 were grown under acetic acid fermentation conditions, and their growth behavior was examined together with their capacity for acetic acid resistance and pellicle formation. In the fermentation process, the cells became aggregated and covered by amorphous materials in the late-log and stationary phases, but dispersed again in the second growth phase (due to overoxidation). The morphological change in the cells was accompanied by changes in sugar contents, which might be related to pellicle polysaccharide formation. To determine the relationship between pellicle formation and acetic acid resistance, a pellicle-forming R strain and a non-forming S strain were isolated, and their fermentation ability and acetic acid diffusion activity were compared. The results suggest that pellicle formation is directly related to acetic acid resistance ability, and thus is important to acetic acid fermentation in these A. pasteurianus strains. PMID:20699583

Kanchanarach, Watchara; Theeragool, Gunjana; Inoue, Taketo; Yakushi, Toshiharu; Adachi, Osao; Matsushita, Kazunobu

2010-01-01

324

Acetate limitation and nitrite accumulation during denitrification  

SciTech Connect

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

Oh, J. [Pohang Univ. of Science and Technology (Korea, Republic of). School of Environmental Engineering] [Pohang Univ. of Science and Technology (Korea, Republic of). School of Environmental Engineering; Silverstein, J. [Univ. of Colorado, Boulder, CO (United States)] [Univ. of Colorado, Boulder, CO (United States)

1999-03-01

325

Enzyme-linked immunosorbent assay-based selection and optimization of elution buffer for TAG72-affinity chromatography  

Microsoft Academic Search

An enzyme-linked immunosorbent assay (ELISA)-elution assay was developed to screen a large variety of elution buffers for selection of a suitable one for purification of the fusion protein FV\\/TNF-? by affinity chromatography. Various commonly used buffer systems utilizing widely differing conditions such as extreme pH, denaturants, chaotropic ions and polarity reducing reagents were investigated. Ammonia solution (1 M, pH 11.5)

Junbao Yang; Terence Moyana; Jim Xiang

1999-01-01

326

Modeling a metal-vapor buffer-gas hollow cathode discharge  

NASA Astrophysics Data System (ADS)

The operation of a metal-vapor buffer-gas hollow cathode discharge is re-examined using modeling techniques that have been developed for electronegative plasma discharges. It is shown that a previously developed global model can be extended to give spatially resolved densities as well as more accurate values for the plasma parameters. A numerical calculation for a neon-copper (Ne-Cu) discharge is used to illustrate the results of the modeling technique. The density profiles of the neutral and ion components, and their variation with the buffer gas pressure, are similar to those found by numerical solution of the complete equations.

Lichtenberg, A. J.; Lieberman, M. A.

2000-05-01

327

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

328

Concentrating aqueous volatile fatty acid salt solutions using a tertiary amine mixture  

E-print Network

Lee (1993) has shown that tertiary amines are able to hics. extract water from low-concentration calcium acetate and sodium acetate solutions. This thesis extends the previous work to include calcium propionate and butyrate. Amine extraction may...

Gaskin, David J

2012-06-07

329

Intracellular free zinc and zinc buffering in human red blood cells.  

PubMed

Zn2+ has been allowed to equilibrate across the red cell membrane using two agents that increase membrane permeability to this ion: the ionophore A23187 and the specific carrier ethylmaltol. Extracellular free Zn2+ was controlled with EGTA (1,2-di(2-aminoethoxy)ethane-NNN'N'tetra-acetic acid] buffers, except in the case of ethylmaltol, which itself acts as a buffer. Measurement of cellular zinc content at different levels of free Zn2+ facilitated the study of intracellular Zn2+ binding. It was also possible to estimate intracellular free Zn2+ concentration in untreated cells using a "null-point" technique. Intracellular zinc was found to consist of an inexchangeable component of about 129 mumol/10(13) cells and an exchangeable component of 6.7 +/- 1.5 mumol/10(13) cells, with a free concentration of about 2.4 x 10(-11) M. The main component of Zn2+ buffering is hemoglobin, with a dissociation constant of about 2 x 10(-8) M. PMID:1774775

Simons, T J

1991-07-01

330

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

PubMed

During storage stability studies of a monoclonal antibody (mAb) it was determined that the primary route of degradation involved fragmentation into lower molecular weight species. The fragmentation was characterized with size-exclusion high performance liquid chromatography (SE-HPLC), SDS-PAGE, and matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. Fragmentation proceeded via hydrolysis, likely catalyzed by trace metal ions, of a peptide bond in the hinge region of the mAb's heavy chain, which produced two prominent low molecular weight species during storage: a single, free Fab fragment and a Fab + Fc fragment. The fragmentation is observed in phosphate-buffered solutions at two ionic strengths but not in histidine-buffered solutions at identical ionic strengths. Chaotrope-induced and thermally induced unfolding studies of the mAb indicated differences in the unfolding pathways between the two buffer solutions. The folding intermediate observed during chaotrope-induced unfolding was further characterized by intrinsic fluorescence quenching, which suggested that a small portion of the molecule is resistant to chaotrope-induced unfolding in histidine buffer systems. The thermally induced unfolding indicates a reduction in cooperativity of the unfolding process in the presence of histidine relative to phosphate. A relationship between the histidine-induced effects on unfolding pathway and the relative resistance to fragmentation is suggested. PMID:20091831

Salinas, Branden A; Sathish, Hasige A; Shah, Ambarish U; Carpenter, John F; Randolph, Theodore W

2010-07-01

331

pH- and concentration-programmable electrodialytic buffer generator.  

PubMed

We have presented in a companion paper a suppressor-based electrodialytic buffer generator (EBG) that can produce programmable pH gradients. Here we demonstrate a three-electrode EBG. In this three-compartment flow-through device, the central compartment is separated from the outer compartments with a cation-exchange membrane (CEM) and an anion-exchange membrane (AEM), respectively. One platinum electrode is disposed in each compartment. The flows through each compartment are independent. With appropriate solutions in each compartment, independent potentials are applied to the CEM and AEM electrodes with respect to the grounded central electrode. The CEM current and the AEM current can be independently manipulated to generate buffers with variable concentration and pH in the central compartment. Both the CEM and AEM currents can be positive or negative. For the CEM, a positive current (i(cat)(in)) indicates that cations are coming in from the CEM channel to the center. A negative current (i(cat)(out)) takes cations out of the center to the CEM channel. Similarly for the AEM, currents governing anion transport into the center channel from the AEM channel (AEM electrode negative) or the reverse (AEM electrode positive) are respectively denoted by i(an)(in) or i(an)(out). Most examples herein involve inward ion transport, referred to as the additive mode. Depending on whether i(cat)(in) i(an)(in), H(+)/O(2) and OH(-)/H(2) are respectively produced at the central electrode to maintain electroneutrality. Any gas formed is subsequently removed by a gas removal device. The pH of the central channel effluent is related to the ratio of the currents through the two membranes, while the generated concentration is controlled by the absolute value of the currents. The buffer concentration and pH can be varied in a controlled predictable manner. A pH span of 3-12 was attained and a phosphate buffer concentration up to 140 mM was generated. We demonstrate a variety of combined pH/concentration gradients from a mixture of ethylenediamine, citrate, and phosphate by manipulating i(cat)(in), which controls introduction of the ethylenediammonium ion, and i(an)(in), which controls the introduction of citrate and phosphate ions. We also demonstrate an additive-subtractive mode of operation where both inward and outward currents are used to add one type of ion while removing another type of ion to reproducibly generate pH/concentration gradients. PMID:22148285

Chen, Yongjing; Edwards, Brian L; Dasgupta, Purnendu K; Srinivasan, Kannan

2012-01-01

332

Buffer control technique for video coding  

NASA Astrophysics Data System (ADS)

In this work we develop an adaptive scheme for quantization of subband or transform coded frames in a typical video sequence coder. Using a simple statistical model for the subband or transform coefficients, we present a procedure to determine the optimum dead-zone quantizer for a given entropy of the quantizer output symbols. We find that, at low bit rates, the dead- zone quantizer offers better performance than the uniform quantizer. The model is used to develop an adaptive procedure to update the quantizer parameters on the basis of the state of a channel buffer with constant output rate and variable input rate. Experimental results show that the model can be effectively used in a practical scheme for buffer control.

Calvagno, Giancarlo; Ghirardi, C.; Mian, Gian A.; Rinaldo, R.

1995-02-01

333

Spacecraft optical disk recorder memory buffer control  

NASA Technical Reports Server (NTRS)

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

Hodson, Robert F.

1993-01-01

334

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.

335

Acute intestinal injury induced by acetic acid and casein: prevention by intraluminal misoprostol  

SciTech Connect

Acute injury was established in anesthetized rabbits by intraluminal administration of acetic acid with and without bovine casein, into loops of distal small intestine. Damage was quantified after 45 minutes by the blood-to-lumen movement of {sup 51}Cr-labeled ethylenediaminetetraacetic acid (EDTA) and fluorescein isothiocyanate-tagged bovine serum albumin as well as luminal fluid histamine levels. The amount of titratable acetic acid used to lower the pH of the treatment solutions to pH 4.0 was increased by the addition of calcium gluconate. Luminal acetic acid caused a 19-fold increase in {sup 51}Cr-EDTA accumulation over saline controls; casein did not modify this effect. In saline controls, loop fluid histamine levels bordered on the limits of detection (1 ng/g) but were elevated 19-fold by acetic acid exposure and markedly increased (118-fold) by the combination of acid and casein. Intraluminal misoprostol (3 or 30 micrograms/mL), administered 30 minutes before acetic acid, significantly attenuated the increase in epithelial permeability (luminal {sup 51}Cr-EDTA, fluorescein isothiocyanate-bovine serum albumin accumulation) and histamine release (P less than 0.05). Diphenhydramine, alone or in combination with cimetidine, and indomethacin (5 mg/kg IV) were not protective. It is concluded that exposure of the epithelium to acetic acid promotes the transepithelial movement of casein leading to enhanced mast cell activation and mucosal injury. Damage to the epithelial barrier can be prevented by misoprostol.

Miller, M.J.; Zhang, x.J.; Gu, x.A.; Clark, D.A. (Department of Pediatrics, Louisiana State University School of Medicine, New Orleans (USA))

1991-07-01

336

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...

337

Sizing Multiple Buffer Pools for A thesis submitted to the  

E-print Network

objects to buffer pools and the setting the size for each of the buffer pools, is crucial for achieving wife, Jie Lu, for their love, support, and encouragement in these years. #12;iii Contents Abstract

338

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

339

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

340

Acetate transport and utilization in the rat brain.  

PubMed

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 (CMR(ace)) 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 (K(M)(util) = 0.01 +/- 0.14 mM) was much smaller than for acetate transport through the blood-brain barrier (BBB) (K(M)(t) = 4.18 +/- 0.83 mM). The maximum transport capacity of acetate through the BBB (V(max)(t) = 0.96 +/- 0.18 micromol/g/min) was nearly twofold higher than the maximum rate of brain acetate utilization (V(max)(util) = 0.50 +/- 0.08 micromol/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 BBB, 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

2009-05-01

341

Acetate and hypercalciuria during total parenteral nutrition13  

Microsoft Academic Search

Hypercalciuria and negative calcium balance are complications oftotal par- enteral nutrition (TPN). Because metabolism ofthe TPN formula generates an acid load that can induce hypercalciuria, we evaluated the effect ofsupplementing the formula with acetate. In a randomized crossover study six patients on continuous and six on cyclic TPN received no added acetate or 160 mmol acetate\\/d replacing 160 mmol chloride\\/d

Charles H Berkelhammer; Richard J Wood; Michael D Sitrin

342

Quality control of histamine and methacholine in diagnostic solutions with capillary electrophoresis.  

PubMed

Solutions of histamine and methacholine bromide in different matrices for diagnostic purposes were analyzed for stability and quality control using capillary electrophoresis. Histamine (2,[4-imidazolyl]ethylamine) [CAS No. 51-45-6] was determined using a 0.1 M Tris-borate buffer of pH 8.3 with 5.10(-5) M cetyltrimethylammonium bromide (CTAB) and 0.005% poly(vinyl alcohol) (PVA) and detected at 214 nm using clenbuterol [4-amino-alpha-(tert.-butylaminomethyl)-3,5-dichlorobenzyl alcohol] [37148-27-9] as an internal standard. Metacholine bromide (acetyl-beta-methacholine bromide) [333-31-3] was determined with a 0.01 M creatinine-chloride buffer of pH 4.85 and detected with indirect UV at 230 nm using potassium as an internal standard. Histamine solutions were stable for a prolonged period of time, whereas under enforced degradation conditions methacholine was hydrolyzed, yielding acetic acid and (tentatively) beta-methylcholine as reaction products. PMID:8777460

van der Schans, M J; Reijenga, J C; Everaerts, F M

1996-05-31

343

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

344

The A -buffer, an antialiased hidden surface method  

Microsoft Academic Search

The A-buffer (anti-aliased, area-averaged, accumulation buffer) is a general hidden surface mechanism suited to medium scale virtual memory computers. It resolves visibility among an arbitrary collection of opaque, transparent, and intersecting objects. Using an easy to compute Fourier window (box filter), it increases the effective image resolution many times over the Z-buffer, with a moderate increase in cost. The A-buffer

Loren Carpenter

1984-01-01

345

Acetate reduces microglia inflammatory signaling in vitro  

PubMed Central

Acetate supplementation increases brain acetyl-CoA and histone acetylation and reduces lipopolysaccharide (LPS)-induced neuroglial activation and interleukin (IL)-1? expression in vivo. To determine how acetate imparts these properties, we tested the hypothesis that acetate metabolism reduces inflammatory signaling in microglia. To test this, we measured the effect acetate treatment had on cytokine expression, mitogen-activated protein kinase (MAPK) signaling, histone H3 at lysine 9 acetylation, and alterations of nuclear factor-kappa B (NF-?B) in primary and BV-2 cultured microglia. We found that treatment induced H3K9 hyperacetylation and reversed LPS-induced H3K9 hypoacetylation similar to that found in vivo. LPS also increased IL-1?, IL-6 and tumor necrosis factor-alpha (TNF-?) mRNA and protein, while treatment returned the protein to control levels and only partially attenuated IL-6 mRNA. In contrast, treatment increased mRNA levels of transforming-growth factor-?1 (TGF-?1) and both IL-4 mRNA and protein. LPS increased p38 MAPK and JNK phosphorylation at 4 and 2–4 hr respectively, while treatment reduced p38 MAPK and JNK phosphorylation only at 2 hr. In addition, treatment reversed the LPS-induced elevation of NF-?B p65 protein and phosphorylation at serine 468 and induced acetylation at lysine 310. These data suggest that acetate metabolism reduces inflammatory signaling and alters histone and non-histone protein acetylation. PMID:22924711

Soliman, Mahmoud L.; Puig, Kendra L.; Combs, Colin K.; Rosenberger, Thad A.

2012-01-01

346

The behaviour of tungsten electrodes in a mixture of acetic acid and acetic anhydride  

Microsoft Academic Search

Summary Tungsten electrodes have advantageously been used for potentiometric end-point detection in perchloric acid titration of bases in a mixture of acetic acid and acetic anhydride. They have also given good results in biamperometric detection of the equivalence point in continuous coulometric titration of small quantities of bases and acids in the same solvent. Tungsten electrodes in the presence of

Tibor J. Pastor; Vilim J. Vajgand

1976-01-01

347

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

348

Water and ions transport mechanism in hyperfiltration with symmetric cellulose acetate membranes  

Microsoft Academic Search

Hyperfiltration is carried out under reverse osmotic conditions by the application of mechanical energy to force the solvent from higher to lower concentration of solute across semipermeable membranes. In the present investigation, experimental work has been performed to measure the water and inorganic cation transport fluxes across cellulose acetate homogeneous hyperfiltration membranes. The osmosis, reverse osmosis, kinetic conductance and membrane

M. Ashraf Chaudry

2002-01-01

349

Properties of cellulose acetate nanofiltration membranes. Application to brackish water desalination  

Microsoft Academic Search

In this work, we report about cellulose acetate nanofiltration (NF) membrane preparation according to the phase inversion process. Pore size was monitored by using dope solutions of two polymer concentrations (20 and 22 wt?%) and annealing temperatures from 60–80°C. Membrane characterization included a morphologic analysis using scanning electron microscopy (SEM) and hydraulic permeability (Lp0) determined from pure water filtration. SEM

Randa Haddada; Ezzedine Ferjani; Mohamed Sadok Roudesli; André Deratani

2004-01-01

350

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

351

On Buffer Limited Congestion Window Dynamics and Packet Loss  

Microsoft Academic Search

The central result of this paper is an analytic formula describing the packet loss probability in a buffer as a function of the length of the buffer and the probability of external packet loss. This formula makes it possible to calculate the total loss along a multi-buffer, multi-link route. Also, new types of congestion win- dow distributions are discovered when

A. Fekete; G. Vattay

2001-01-01

352

Centralized Buffer Router with Elastic Links and Bubble Flow Control  

E-print Network

Centralized Buffer Router with Elastic Links and Bubble Flow Control Syed Minhaj Hassan Georgia: sudha@ece.gatech.edu Abstract--While router buffers have been used as performance multipliers elastic bubble router - a router micro-architecture based on the use of centralized buffers (CB

Lee, Hsien-Hsin "Sean"

353

Energy management using buffer memory for streaming data  

Microsoft Academic Search

This work presents a new approach for energy management by inserting data buffers. The buffers are managed using the concept of inventory control by treating energy as cost and computation as production. The data stored in the buffers are considered as merchandise. Our method provides a mathematical framework to develop general strategies managing the energy consumption in computers. The approach

Le Cai; Yung-hsiang Lu

2005-01-01

354

CS281: Systems Programming Programming Lab Assignment: The Buffer Bomb  

E-print Network

CS281: Systems Programming Programming Lab Assignment: The Buffer Bomb Introduction This assignment You can obtain your buffer bomb by pointing your Web browser at: http the following three executable files: bufbomb: The buffer bomb program you will attack. 1 #12;makecookie

Kretchmar, R. Matthew

355

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 Co (GDRCo) applies tree retention buffers to steep slopes along fish bearing (Class I) and non with timber harvest plans. These Steep Streamside Slope (SSS) buffers were designed to reduce the amount

Standiford, Richard B.

356

Buffer block planning for interconnect-driven floorplanning  

Microsoft Academic Search

This paper studies buffer block planning for interconnect-driven floorplanning in deep submicron designs. We first introduce the concept of feasible region (FR) for buffer insertion, and derive closed-form formula for FR. We observe that the FR for a buffer is quite large in general even under fairly tight delay constraint. Therefore, FR gives us a lot of flexibility to plan

Jason Cong; Tianming Kong; David Zhigang Pan

1999-01-01

357

Box Calculus with High-Level Buffers Ccile Bui Thanh  

E-print Network

Box Calculus with High-Level Buffers Cécile Bui Thanh LACL, Université Paris 12 61 avenue du: Process algebra, handshake/buffered commu- nication, structured operational semantics, coloured Petri nets both handshake and buffered communication. This allows a sim- ple and compositional expression

Paris-Sud XI, Université de

358

Exact Analysis of Single-Wavelength Optical Buffers With Feedback  

E-print Network

Exact Analysis of Single-Wavelength Optical Buffers With Feedback Markov Fluid Queues Huseyin Emre Kankaya and Nail Akar Abstract--Optical buffering via fiber delay lines is used for contention resolution the blocking probabili- ties in an asynchronous single-wavelength optical buffer. Packet lengths are assumed

Akar, Nail

359

PERFORMANCE ANALYSIS OF NETWORKS OF OPEN ZERO-BUFFER  

E-print Network

PERFORMANCE ANALYSIS OF NETWORKS OF OPEN ZERO-BUFFER MULTI-SERVER QUEUES Frederico R. B. Cruz (UFMG) fcruz@est.ufmg.br In this paper we aim to accurately evaluate the performance of open zero-buffer multi to 09 October - 2009 #12;2 1. Introduction and Motivation Networks of finite queues without buffers

Cruz, Frederico

360

Predicting buffer hit ratios with neural networks Uli Harder  

E-print Network

Predicting buffer hit ratios with neural networks Uli Harder and Tim MacLeod September 18, 2003 Abstract A neural network is used to predict the buffer hit ratio in an Oracle database, given the access pattern and buffer size. 1 Introduction Neural networks have come and gone into fashion several times over

Imperial College, London

361

Quantification of the Effects of Organic and Carbonate Buffers on  

E-print Network

Quantification of the Effects of Organic and Carbonate Buffers on Arsenate and Phosphate Adsorption evaluation of their adsorptive capacities. Here, we systematically investigate the effects of buffer (HEPES as a buffer. At low aqueous arsenate and phosphate concentration (1.3 µM), however

Sverjensky, Dimitri A.

362

Optimizing buffer sizes for pipeline workflow scheduling with setup times  

E-print Network

Optimizing buffer sizes for pipeline workflow scheduling with setup times Anne Benoit1, Jean and homogeneous buffers are available for the storage of intermediate results. In this kind of applications, several computation stages are interconnected as a linear application graph, and each stage holds a buffer

Benoit, Anne

363

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, variable width metallic wires. By employing laser desorption of a physisorbed buffer gas, a grating of gold controlled metallic clusters via buffer layer assisted growth (BLAG).9-11 To create clusters, the metal

Asscher, Micha

364

Optimal Buffer Management Policies for Delay Tolerant Networks  

E-print Network

Optimal Buffer Management Policies for Delay Tolerant Networks Amir Krifa, Chadi Barakat proposed the use of store-carry-and-forward protocols: there, a node may store a message in its buffer). Thus, efficient buffer manage- ment policies are necessary to decide which messages should be discarded

Paris-Sud XI, Université de

365

PointGuardTM: Protecting Pointers From Buffer Overflow Vulnerabilities  

Microsoft Academic Search

Despite numerous security technologies crafted to resist buffer overflow vulnerabilities, buffer overflows continue to be the dominant form of software security vulnerability. This is because most buffer overflow defenses provide only partial coverage, and the attacks have adapted to exploit problems that are not well-defended, such as heap over- flows. This paper presents PointGuard, a compiler technique to defend against

Crispin Cowan; Steve Beattie; John Johansen; Perry Wagle

2003-01-01

366

Optimal Buffer Allocation in Production Lines Using an Automata Search  

E-print Network

Optimal Buffer Allocation in Production Lines Using an Automata Search Tolga Tezcan Abhijit Gosavi, to solve the optimal buffer allocation problem in production lines. We have incorporated the search optimization problems. In this paper, we use an LA based search technique for finding the optimal buffer sizes

Gosavi, Abhijit

367

On the performance of greedy algorithms in packet buffering  

Microsoft Academic Search

We study a basic buffer management problem that arises in network switches. Consider m input ports, each of which is equipped with a buffer (queue) of limited capacity. Data packets arrive online and can be stored in the buffers if space permits; otherwise packet loss occurs. In each time step the switch can transmit one packet from one of the

Susanne Albers; Markus Schmidt

2004-01-01

368

A fair queueing architecture for ATM switches with input buffers  

Microsoft Academic Search

The available bit rate (ABR) and unspecified bit rate (UBR) are reservationless service categories at the ATM layer. ATM switches are required to have large cell buffers to provide such services. A new queueing architecture named Kago for the large input buffer switch is proposed. Kago provides per-VC fair scheduling among the multiple input buffers. The mechanism is divided among

Yosliiniitsu Shimojo; Toshiba Corp

1996-01-01

369

Meta-Analysis of Nitrogen Removal in Riparian Buffers  

Microsoft Academic Search

Riparian buffers, the vegetated region adjacent to streams and wet- lands, are thought to be effective at intercepting and reducing nitrogen loads entering water bodies. Riparian buffer width is thought to be positively related to nitrogen removal effectiveness by influencing nitrogen retention or removal. We surveyed the scientific literature containing data on riparian buffers and nitrogen concentration in streams and

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

2007-01-01

370

Electrochemical generation of manganese(III) and behaviour of the generated oxidant in acetic acid in the presence of perchlorate ions  

Microsoft Academic Search

Summary Research was carried out to determine conditions for the anodic generation of manganese(III) with high current efficiency in solutions of sodium perchlorate in acetic acid, and to examine the behaviour of the oxidant thus generated. The effects of water and acetic anhydride on current efficiency in the generation of the oxidant was also examined. The formal redox potential of

Tibor J. Pastor; Ivan ?iri?

1984-01-01

371

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

372

Acetic acid mediated interactions between alumina surfaces  

NASA Astrophysics Data System (ADS)

Low-molecular-weight organic acids have been known to modify colloidal stability of alumina-based suspensions. We investigated interaction forces between alumina surfaces mediated by acetic acid which is one of the simplest organic acids. Forces between alumina surfaces were measured using the colloid-probe method of atomic force microscope (AFM). Repulsive forces attributed to steric repulsion due to adsorbed molecules and electrostatic repulsion dominated the interaction. Results of rheological characterization of the alumina slurry containing acetic acid supported the finding.

Sato, Kimiyasu; Y?lmaz, Hüseyin; Ijuin, Atsuko; Hotta, Yuji; Watari, Koji

2012-02-01

373

The in vitro biocompatibility performance of a 25 mmol\\/L bicarbonate\\/10 mmol\\/L lactate-buffered peritoneal dialysis fluid  

Microsoft Academic Search

The in vitro biocompatibility performance of a 25 mmol\\/L bicarbonate\\/10 mmol\\/L lactate-buffered peritoneal dialysis fluid.Background. The biocompatibility profile of a new peritoneal dialysis (PD) solution (Physioneal 35) was determined using a selection of in vitro assay systems. Physioneal 35 is buffered by a combination of 25 mmol\\/L bicarbonate and 10 mmol\\/L lactate, thereby providing a solution with a total of

LINE SKOUFOS; NICHOLAS TOPLEY; LAURINDA COOKER; ANNE DAWNAY; David J. Millar; Clifford J. Holmes; DIRK FAICT

2003-01-01

374

Buffer insertion is an increasingly critical optimization for achieving timing closure, and the number of buffers required  

E-print Network

ABSTRACT Buffer insertion is an increasingly critical optimization for achieving timing closure, and the number of buffers required increases significantly with technology migration. It is imperative for an automated buffer insertion algorithm to be able to efficiently optimize tens of thousands of nets. One must

Hu, Jiang

375

Phorbol myristate acetate and dioctanoylglycerol inhibit transport in rabbit proximal convoluted tubule  

Microsoft Academic Search

The present in vitro microperfusion study examined the effect of protein kinase C activation on transport in the rabbit proximal convoluted tubule (PCT). PCT were perfused with an ultrafiltrate-like solution and were bathed in a serumlike albumin solution. Addition of phorbol 12-myristate 13-acetate, an activator of protein kinase C, inhibited volume absorption from 1.06 {plus minus} 0.10 to 0.77 {plus

M. Baum; S. R. Hays

1988-01-01

376

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

DOEpatents

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

Kruger, Hans W. (Walnut Creek, CA)

1994-01-01

377

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

DOEpatents

A buffer assembly is disclosed for a gamma-insensitive gas avalanche focal plane array operating in the ultra-violet/visible/infrared energy wavelengths and using a photocathode and an avalanche gas located in a gap between an anode and the photocathode. The buffer assembly functions to eliminate chemical compatibility between the gas composition and the materials of the photocathode. The buffer assembly in the described embodiment is composed of two sections, a first section constructed of glass honeycomb under vacuum and a second section defining a thin barrier film or membrane constructed, for example, of Al and Be, which is attached to and supported by the honeycomb. The honeycomb section, in turn, is supported by and adjacent to the photocathode. 7 figures.

Kruger, H.W.

1994-05-10

378

Acetate inhibition of chick bone cell proliferation and bone growth in vitro.  

PubMed

A hypothesis has been advanced that parenteral solutions as commonly formulated for use in clinical practice have a toxic effect on cell metabolism. A specific component of these solutions, sodium acetate, has been suggested to disrupt normal bone turnover and therefore to contribute to the osteopenia observed in patients receiving hemodialysis and parenteral nutrition (PN). We developed an in vitro model to test the hypothesis that sodium acetate at concentrations that are infused in PN solutions has a deleterious effect on bone metabolism. Osteoblasts and preosteoblasts from 16- to 17-day-old embryonic chick calvaria, and tibiae and femora from 10-day-old embryonic chicks were grown in BGJb medium (control) or in BGJb medium plus sodium acetate (5, 10, or 20 mM). Calvarial cell proliferation was quantified by direct cell counts as well as by incorporation of [3H]TdR into DNA as an index of cell proliferation. Calvarial cell alkaline phosphatase activity was quantified by the ability of extracts of the cultured cells to hydrolyze p-nitrophenyl phosphate to p-nitrophenol, and bone growth was determined by measuring final dry weight. Calvarial cell counts as well as DNA synthesis showed a dose-dependent decrease in the presence of sodium acetate (5-20 mM) compared with controls. [3H]TdR incorporation was decreased a mean 19% with 5 mM, 38% with 10 mM, and 63% with 20 mM acetate. Alkaline phosphatase activity per cell increased 48% with 5 mM, 140% with 10 mM, and 355% with 20 mM acetate. Cell viability as assessed by trypan blue exclusion was identical for test and control media (greater than 95%).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2763873

Saitta, J C; Lipkin, E W; Howard, G A

1989-06-01

379

Fabrication of Porous Metal Oxide Semiconductor Films by a Self-Template Method Using Layered Hydroxide Metal Acetates  

Microsoft Academic Search

Porous metal oxide (Co3O4, NiO, or ZnO) films were fabricated by a self-template method using layered hydroxide metal acetates (LHMA; metal = Co, Ni, or Zn) as templates. LHMAs were initially grown on glass substrates through a chemical bath deposition in methanolic-aqueous solutions of metal acetates at 60°C. The template films had a unique, nest-like morphology consisting of interlaced flake-like

Shinobu Fujihara; Eiji Hosono; Toshio Kimura

2004-01-01

380

Shear and Extensional Rheology of Cellulose/Ionic Liquid Solutions  

E-print Network

In this study, we characterize the shear and extensional rheology of dilute to semidilute solutions of cellulose in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIAc). In steady shear flow, the semidilute solutions ...

Haward, Simon J.

381

Hybrid Silicon AWG Lasers and Buffers  

NASA Astrophysics Data System (ADS)

Silicon photonics promises the low cost integration of optical components with CMOS electronics thus enabling optical interconnects in future generation processors. The hybrid silicon platform (HSP) is one approach to make optically active components on silicon. While many optical components on the HSP have been demonstrated, few photonic integrated circuits (PICs), consisting of multiple elements, have been demonstrated. In this dissertation, two Hybrid Silicon PICs and their building blocks will be presented. The first PIC to be presented is a multiwavelength laser based on an AWG. It consists of Fabry-Perot cavities integrated with hybrid silicon amplifiers and an intracavity filter in the form of an AWG with a channel spacing of 360 GHz. Four-channel lasing operation is shown. Single-sided fiber-coupled output powers as high as 35 µW are measured. The SMSR is as high as 35 dB. Various device characteristics are compromised as the AWG was attacked during the III-V process, thus showing the need to properly protect passive components during III-V processing. The second PIC to be presented is a fully integrated optical buffer. The device consists of a hybrid silicon switch, a 1.1 m long silicon waveguide, and cascaded hybrid silicon amplifiers. The passive delay line is protected by dielectric layers to limit passive losses to 0.5 dB/cm. Noise filters in the form of saturable absorbers are integrated in the buffer to allow for a larger number of recirculations in the delay line compared to a delay without filters. Tapers are used to transition the mode from the passive region to the hybrid region with losses as low as 0.22 dB per transition and reflectivities below -35 dB. Error free operation of the hybrid silicon switch is demonstrated in all four paths. The integrated buffer failed due to low yield, showing the current limitations of the HSP.

Kurczveil, Geza

382

Spacecraft optical disk recorder memory buffer control  

NASA Technical Reports Server (NTRS)

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

Hodson, Robert F.

1992-01-01

383

Seasonal buffering of atmospheric pressure on Mars  

NASA Technical Reports Server (NTRS)

An isothermal reservoir of carbon dioxide in gaseous contact with the Martian atmosphere would reduce the amplitude and advance the phase of global atmospheric pressure fluctuations caused by seasonal growth and decline of polar CO2 frost caps. Adsorbed carbon dioxide in the upper roughly 10 m of Martian regolith is sufficient to buffer the present atmosphere on a seasonal basis. Available observations and related polar cap models do not confirm or refute the operation of such a mechanism. Implications for the amplitude and phase of seasonal pressure fluctuations are subject to direct test by the upcoming Viking mission to Mars.

Dzurisin, D.; Ingersoll, A. P.

1975-01-01

384

A Buffer Management Issue in Designing SSDs for LFSs  

NASA Astrophysics Data System (ADS)

This letter introduces a buffer management issue in designing SSDs for log-structured file systems (LFSs). We implemented a novel trace-driven SSD simulator in SystemC language, and simulated several SSD architectures with the NILFS2 trace. From the results, we give two major considerations related to the buffer management as follows. (1) The write buffer is used as a buffer not a cache, since all write requests are sequential in NILFS2. (2) For better performance, the main architectural factor is the bus bandwidth, but 332MHz is enough. Instead, the read buffer makes a key role in performance improvement while caching data. To enhance SSDs, accordingly, it is an effective way to make efficient read buffer management policies, and one of the examples is tracking the valid data zone in NILFS2, which can increase the data hit ratio in read buffers significantly.

Kim, Jaegeuk; Seol, Jinho; Maeng, Seungryoul

385

Immunotoxicity of Trenbolone Acetate in Japanese Quail  

Microsoft Academic Search

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

Michael James Quinn; Moira McKernan; Emma T. Lavoie; Mary Ann Ottinger

2006-01-01

386

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2013 CFR

21 Food and Drugs 1 2013-04-01 2013-04-01...acetate. 73.2396 Section 73.2396 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...than 4.7 and not more than 5.8. Arsenic (as As), not more than 3 parts...

2013-04-01

387

Drying Cellulose Acetate Reverse Osmosis Membranes.  

National Technical Information Service (NTIS)

The membranes currently used in reverse osmosis for desalination are made of cellulose acetate. Modified membranes, because they contain a large number of pores, contain large quantities of water, 60 to 70 wt. %. If this water is allowed to evaporate unde...

K. D. Vos, F. O. Burris

1967-01-01

388

Heat Bonding of Irradiated Ethylene Vinyl Acetate  

NASA Technical Reports Server (NTRS)

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

Slack, D. H.

1986-01-01

389

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

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

1998-02-17

390

Strengths of the Chloro-acetic Acids  

Microsoft Academic Search

IT is well known that the introduction of chlorine atoms into acetic acid causes a rapid rise of dissociation constant (see ). If changes in the value of K are taken as a measure of the effect of the chlorine atoms, it would appear that the second chlorine atom has a greater effect than the first, and the third a

John Shorter; F. J. Stubbs

1949-01-01

391

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

392

Corrosion of stainless steel during acetate production  

SciTech Connect

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

Qi, J.S.; Lester, G.C. [Occidental Chemical Corp. Technology Center, Grand Island, NY (United States)

1996-07-01

393

Fermentative biohydrogen production from lactate and acetate.  

PubMed

In this study, a continuous-flow stirred tank reactor (CSTR) fed with lactate and acetate was operated to enrich hydrogen-producing bacteria. By varying the influent substrate concentrations and hydraulic retention times (HRT), the volumetric loading rate (VLR) of 55.64 kg-COD/m(3)/day seemed to be optimum for this enriched culture for fermentative hydrogen production from lactate and acetate. The results of batch experiments confirmed that the enriched culture tended to fulfill the e(-) equiv requirement for cell growth at a lower VLR condition (21.77 kg-COD/m(3)/day), while it could largely distribute the e(-) equiv for hydrogen production at a higher VLR condition. However, a maximum lactate/acetate concentration allowed for enriching this culture existed, especially at a lower HRT condition in which wash-out can be an issue for this enriched culture. Finally, the results of cloning and sequencing indicated that Clostridium tyrobutyricum was considered the major hydrogen-producing bacteria in the CSTR fed with lactate and acetate. PMID:22318084

Wu, Chao-Wei; Whang, Liang-Ming; Cheng, Hai-Hsuan; Chan, Kan-Chi

2012-06-01

394

Buffers in daphnid culture and bioassay  

SciTech Connect

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

Keating, K.I.; Caffrey, P.B.; Dagbusan, B.C. [Rutgers-the State Univ., New Brunswick, NJ (United States). Dept. of Environmental Science

1996-03-01

395

Continuous processing of recombinant proteins: integration of refolding and purification using simulated moving bed size-exclusion chromatography with buffer recycling.  

PubMed

Continuous processing of recombinant proteins was accomplished by combining continuous matrix-assisted refolding and purification by tandem simulated moving bed (SMB) size-exclusion chromatography (SEC). Recombinant proteins, N(pro) fusion proteins from inclusion bodies were dissolved with NaOH and refolded in the SMB system with a closed-loop set-up with refolding buffer as the desorbent buffer and buffer recycling of the refolding buffer of the raffinate by tangential flow filtration. For further purification of the refolded proteins, a second SMB operation also based on SEC was added. The whole system could be operated isocratically with refolding buffer as the desorbent buffer, and buffer recycling could also be applied in the purification step. Thus, a significant reduction in buffer consumption was achieved. The system was evaluated with two proteins, the N(pro) fusion pep6His and N(pro) fusion MCP-1. Refolding solution, which contained residual N(pro) fusion peptide, the cleaved autoprotease N(pro), and the cleaved target peptide was used as feed solution. Full separation of the cleaved target peptide from residual proteins was achieved at a purity and recovery in the raffinate and extract, respectively, of approximately 100%. In addition, more than 99% of the refolding buffer of the raffinate was recycled. A comparison of throughput, productivity, and buffer consumption of the integrated continuous process with two batch processes demonstrated that up to 60-fold higher throughput, up to 180-fold higher productivity, and at least 28-fold lower buffer consumption can be obtained by the integrated continuous process, which compensates for the higher complexity. PMID:24630055

Wellhoefer, Martin; Sprinzl, Wolfgang; Hahn, Rainer; Jungbauer, Alois

2014-04-11

396

Experimental study of aluminum-acetate complexing between 60 and 200°c  

NASA Astrophysics Data System (ADS)

The solubilities of bayerite and boehmite were measured as a function of pH and acetate concentration at temperatures from 60 to 200°C, to determine the stoichiometries and stability constants of aluminum-acetate complexes. Analysis of these solubility data indicate that the three aluminumacetate complexes, AlAcO 2+, Al(OH) AcO + and Al(AcO) +2 are significant. The logarithm of the stability constants of these complexes are found to be linearly related to the reciprocal of temperature over the range 60-200°C. The slopes of these relationships yield association enthalpies of 7˜5 kJ/mol. Thermodynamic calculations indicate that acetate can markedly enhance the solubility of Al-bearing minerals in sedimentary basin fluids over the temperature range from 100 to 200°C, at pH < 5, but have little effect in solutions having higher pHs.

Benezeth, Pascale; Castet, Sylvie; Dandurand, Jean-Louis; Gout, Robert; Schott, Jacques

1994-11-01

397

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

398

Trypanosomatidae Produce Acetate via a Mitochondrial Acetate:Succinate CoA Transferase  

Microsoft Academic Search

Hydrogenosome-containing anaerobic protists, such as the trichomonads, produce large amounts of acetate by an acetate:succinate CoA transferase (ASCT)\\/succinyl CoA synthetase cycle. The notion that mitochondria and hydrogenosomes may have originated from the same alpha -proteobacterial endosymbiont has led us to look for the presence of a similar metabolic pathway in trypanosomatids because these are the earliest-branching mitochondriate eukaryotes and because

Jaap J. van Hellemond; Fred R. Opperdoes; Aloysius G. M. Tielens

1998-01-01

399

Solid–liquid equilibrium in the acetic acid–acetophenone and acetic acid–formamide systems  

Microsoft Academic Search

Solid–liquid equilibrium in the binary systems acetic acid–acetophenone and acetic acid–formamide was determined from time–temperature cooling and warming curves. The first system shows a sagged curve with a eutectic point at x1?0.6 and T=267.18 K. In the second system a solid compound (2:1) was found and an equilibrium constant of the compound dissociation was calculated.

I. Malijevská; Z. Sedláková

2006-01-01

400

Ion-release, dissolution and buffering by zinc phosphate dental cements  

Microsoft Academic Search

The interaction of zinc phosphate dental cement with aqueous solutions has been studied in order to elucidate the relationship between pH change and ion release (dissolution). For each storage medium (deionized water, lactic acid at pH 2.7 and lactate buffer at pH 2.2) five cylindrical specimens of zinc phosphate cement (6 mm diameter×12 mm height) were prepared and weighed. They

Beata Czarnecka; Honorata Limanowska-Shaw; John W. Nicholson

2003-01-01

401

Using single buffers and data reorganization to implement a multi-megasample fast Fourier transform  

NASA Technical Reports Server (NTRS)

Data ordering in large fast Fourier transforms (FFT's) is both conceptually and implementationally difficult. Discribed here is a method of visualizing data orderings as vectors of address bits, which enables the engineer to use more efficient data orderings and reduce double-buffer memory designs. Also detailed are the difficulties and algorithmic solutions involved in FFT lengths up to 4 megasamples (Msamples) and sample rates up to 80 MHz.

Brown, R. D.

1992-01-01

402

Influence of carbon and buffer amendment on ammonia volatilization in composting  

Microsoft Academic Search

Laboratory-scale experiments were carried out to test a mathematical model of the nitrogen dynamics in a composting process. The main ingredients of composting materials were wheat straw and dairy manure. The influence of (a) two carbon amendments, i.e. molasses and office paper, and (b) two chemicals forming buffer solutions on ammonia volatilization were investigated. Nitrogen losses amounted to 12–25% of

Y. Liang; J. J. Leonard; J. J. R. Feddes; W. B. McGill

2006-01-01

403

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

404

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

405

An electrochemical method for the measurements of substrate-oxidizing activity of acetic acid bacteria using a carbon-paste electrode modified with immobilized bacteria  

Microsoft Academic Search

In order to measure the substrate-oxidizing activity of intact cells of Acetobacter pasteurianus no.?2, a given amount of the bacterial cells was immobilized on a carbon-paste electrode, and the current at the electrode\\u000a was measured in a buffer solution. When Fe(CN)3?\\u000a 6 was added to the buffer solution, an anodic current was observed at 0.5?V (against Ag\\/AgCl). Further, when ethanol

T. Kondo; T. Ikeda

1999-01-01

406

Swelling kinetics of spray-dried chitosan acetate assessed by magnetic resonance imaging and their relation to drug release kinetics of chitosan matrix tablets  

Microsoft Academic Search

Magnetic resonance imaging (MRI) was used to assess in situ swelling behaviors of spray-dried chitosan acetate (CSA) in 0.1N HCl, pH 6.8 and pH 5.0 Tris–HCl buffers. The in vitro drug releases from CSA matrix tablets containing the model drugs, diclofenac sodium and theophylline were investigated in all media using USP-4 apparatus. The effect of chitosan molecular weight, especially in

Kampanart Huanbutta; Pornsak Sriamornsak; Sontaya Limmatvapirat; Manee Luangtana-anan; Yasuo Yoshihashi; Etsuo Yonemochi; Katsuhide Terada; Jurairat Nunthanid

2011-01-01

407

INFORMATIONAND CONTROL63, 88-112 (1984) Can Message Buffers Be Axiomatized  

E-print Network

INFORMATIONAND CONTROL63, 88-112 (1984) Can Message Buffers Be Axiomatized Linear Temporal Logic buffers (queues), LIFO buffers (stacks) and unordered buffers (bags). We show that all bounded buffers of unboun- ded FIFO buffers is ~l-complete and so is not axiomatizable. We also prove that the theories

Clarke, Edmund M.

408

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

409

Huge capacity optical packet switching and buffering.  

PubMed

We demonstrate 2.56 Tbit/s/port dual-polarization DWDM/DQPSK variable-length optical packet (20 Gbit/s × 64 wavelengths × 2 polarizations) switching and buffering by using a 2×2 optical packet switch (OPS) system. The optical data plane of the OPS system was constructed of multi-connected electro-optical switches and fiber delay lines. The accumulated polarization dependent loss of each optical path in the data plane was less than 5 dB. This low-polarization-dependence OPS system enabled us to handle DWDM/DQPSK optical packets (1.28 Tbit/s/port) with time-varying polarization after transmission through 100 km fiber in the field. PMID:22274050

Shinada, Satoshi; Furukawa, Hideaki; Wada, Naoya

2011-12-12

410

Buffered electropolishing parameters on niobium sheet  

SciTech Connect

In this paper, studies on applying a new electrolyte to treat the surfaces of Nb sheets, which was called buffered electropolishing (BEP), were reported. Through studies of the BEP I-V characteristic and optimization of main parameters such as acid agitation, temperature, etc., much faster Nb polishing rate and smoother surface finish were achieved in comparison with those obtained from the conventional electropolishing (EP). The average polishing rate could reach around 2.5 ???m/min. It was over 7 times faster than that of the traditional EP. Meanwhile, the average surface mean square root roughness was around 50 nm over an area of (200×200)???m2. This study shows BEP has a great potential to replace the traditional EP process and becomes a new generation of technology for treating Nb superconducting radio frequency cavities.

Song Jin, Xiangyang Lu, Lin Lin, Andy T. Wu, Kui Zhao

2010-06-01

411

Surface Treatments of Nb by Buffered Electropolishing  

SciTech Connect

Buffered electropolishing (BEP) is a Nb surface treatment technique developed at Jefferson Lab1. Experimental results obtained from flat Nb samples show2-4 that BEP can produce a surface finish much smoother than that produced by the conventional electropolishing (EP), while Nb removal rate can be as high as 4.67 ?m/min. This new technique has been applied to the treatments of Nb SRF single cell cavity employing a vertical polishing system5 constructed at JLab as well as a horizontal polishing system at CEA Saclay. Preliminary results show that the accelerating gradient can reach 32 MV/m for a large grain cavity and 26.7 MV/m for a regular grain cavity. In this presentation, the latest progresses from the international collaboration between Peking University, CEA Saclay, and JLab on BEP will be summarized.

Wu, Andy T. [JLAB; Rimmer, Robert A. [JLAB; Ciovati, Gianluigi [JLAB; Manus, Robert L. [JLAb; Reece, Charles E. [JLAB; Williams, J. S. [JLAB; Eozénou, F. [CEA, Gif-sur-Yvette; Jin, S. [PKU/IHIP, Beijing; Lin, L. [PKU/IHIP, Beijing; Lu, X.Y. [PKU/IHIP, Beijing; Mammosser, John D. [JLAB; Wang, E. [BNL

2009-11-01

412

Studies of solution deposited cerium oxide thin films on textured Ni-alloy substrates for YBCO superconductor  

SciTech Connect

Cerium oxide (CeO{sub 2}) buffer layers play an important role for the development of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) based superconducting tapes using the rolling assisted biaxially textured substrates (RABiTS) approach. The chemical solution deposition (CSD) approach has been used to grow epitaxial CeO{sub 2} films on textured Ni-3 at.% W alloy substrates with various starting precursors of ceria. Precursors such as cerium acetate, cerium acetylacetonate, cerium 2-ethylhexanoate, cerium nitrate, and cerium trifluoroacetate were prepared in suitable solvents. The optimum growth conditions for these cerium precursors were Ar-4% H{sub 2} gas processing atmosphere, solution concentration levels of 0.2-0.5 M, a dwell time of 15 min, and a process temperature range of 1050-1150 deg. C. X-ray diffraction, AFM, SEM, and optical microscopy were used to characterize the CeO{sub 2} films. Highly textured CeO{sub 2} layers were obtained on Ni-W substrates with both cerium acetate and cerium acetylacetonate as starting precursors. YBCO films with a J {sub c} of 1.5 MA/cm{sup 2} were obtained on cerium acetylacetonate-based CeO{sub 2} films with sputtered YSZ and CeO{sub 2} cap layers.

Stewart, E. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Bhuiyan, M.S. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Sathyamurthy, S. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Paranthaman, M. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States)]. E-mail: paranthamanm@ornl.gov

2006-06-15

413

Studies of Solution Deposited Cerium Oxide Thin Films on Textured Ni-Alloy Substractes for YBCO Superconductor  

SciTech Connect

Cerium oxide (CeO2) buffer layers play an important role for the development of YBa2Cu3O7-x (YBCO) based superconducting tapes using the rolling assisted biaxially textured substrates (RABiTS) approach. The chemical solution deposition (CSD) approach has been used to grow epitaxial CeO2 films on textured Ni-3 a 4% W alloy substrates with various starting precursors of ceria. Precursors such as cerium acetate, cerium acetylacetonate, cerium 2-ethylhexanoate, cerium nitrate, and cerium trifluoroacetate were prepared in suitable solvents. The optimum growth conditions for these cerium precursors were Ar-4% H2 gas processing atmosphere, solution concentration levels of 0.2-0.5 M, a dwell time of 15 min, and a process temperature range of 1050-1150 degrees C. X-ray diffraction, AFM, SEM, and optical microscopy were used to characterize the CeO2 films. Highly textured CeO2 layers were obtained on Ni-W substrates with both cerium acetate and cerium acetylacetonate as starting precursors. YBCO films with a Jc of 1.5 MA/cm2 were obtained on cerium acetylacetonate-based CeO2 films with sputtered YSZ and CeO2 cap layers.

Stewart, Erin L [ORNL; Bhuiyan, Md S [ORNL; Sathyamurthy, Srivatsan [ORNL; Paranthaman, Mariappan Parans [ORNL

2006-01-01

414

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

415

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

416

Molecular Biology Buffers And Solutions NOTE: Use ACS grade chemicals, and dH2O for all buffers.  

E-print Network

.5, 1 mM EDTA, 15 mM NaCl 2. Place in boiling water bath for 15 minutes. 3. Cool slowly to room. Carbenicillin or Ampicillin Stock Aliquots 1. Dissolve 1.0 g of carbenicillin or ampicillin (sodium salt) in 10H2O. 2. Prepare 250 mM adenosoine (Sigma A-9251): 2 g in 30 ml dH2O. Heat to near boiling while

Aris, John P.

417

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

E-print Network

glyoxal (aliquots at -70°C). 2. Mix with 1.5 ml DMSO (Aldrich HPLC Grade Methyl Sulfoxide). 3. Add 0.3 ml tracking dyes Deionized Glyoxal: 1. Thaw 40% glyoxal stock, warm to 50°C, and transfer 20 ml to a 50 ml plastic tube. Transfer the remainder of the glyoxal stock to 50 ml tubes, parafilm, and immediately freeze

Aris, John P.

418

Separating acetic acid from furol (furfural) by electrodialysis method  

SciTech Connect

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

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

1981-01-01

419

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

Microsoft Academic Search

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

W. Kindermann; J. Keul; G. Huber

1977-01-01

420

The accumulation buffer: hardware support for high-quality rendering  

Microsoft Academic Search

This paper describes a system architecture that supports realtime generation of complex images, efficient generation of extremely high-quality images, and a smooth trade-off between the two.Based on the paradigm of integration, the architecture extends a state-of-the-art rendering system with an additional high-precision image buffer. This additional buffer, called the Accumulation Buffer, is used to integrate images that are rendered into

Paul Haeberli; Kurt Akeley

1990-01-01

421

Development of buffers for fast semidry transfer of proteins.  

PubMed

Western blot is an extensively used method for protein detection in cell biology. To optimize this procedure, here we examined a panel of buffers for their ability to efficiently transfer proteins from SDS-polyacrylamide gels onto nitrocellulose membranes in a short 12-min period, designated here as fast semidry transfer. Our results show for the first time that HEPES- and HEPPS/EPPS-based buffers represent the most efficient buffers for fast semidry transfer. PMID:23872007

Gari?, Dušan; Humbert, Laure; Fils-Aimé, Nadège; Korah, Juliana; Zarfabian, Yasaman; Lebrun, Jean-Jacques; Ali, Suhad

2013-10-15

422

On organism: environment buffers and their ecological significance  

Microsoft Academic Search

We consider, from a physical perspective, the case where the interface between an organism and its environment becomes large\\u000a enough that it acts as a buffer regulating their matter and energy exchanges. We illustrate the physiological and evolutionary\\u000a role of buffers through the example of lungfish estivation. Then we ponder the relevance of buffers of this kind to the quest

José-Leonel Torres; Lynn Trainor

2008-01-01

423

Chromatographic transport of alkaline buffers through reservoir rock  

Microsoft Academic Search

Use of relatively low-pH alkaline buffers, such as sodium carbonate or sodium silicate, is explored as a means for overcoming sodium\\/hydrogen ion-exchange delay in alkaline waterflooding. A local equilibrium chromatographic model is outlined to describe the concentration velocities for injection of alkaline buffers into a linear porous medium which exhibits reversible sodium\\/hydrogen exchange. The theory predicts a buffer ion-exchange wave

J. A. Jensen; C. J. Radke

1985-01-01

424

l-Lysinium trifluoro-acetate.  

PubMed

Ions of the title compound, C(6)H(15)N(2)O(2) (+)·C(2)F(3)O(2) (-), a new organic nonlinear optical crystal, are linked by N-H?O hydrogen-bonding inter-actions. Both the amino groups of the l-lysinium cation are protonated. A three-dimensional network of hydrogen bonds is observed, forming a closed ring. Inter-molecular N-H?O hydrogen bonds involving l-lysinium cations and trifluoro-acetate anions link the ions into extended chains which run parallel to the [010] direction. The F atoms of the trifluoro-acetate anion are disordered over two sites with site occupancies of 0.423?(18) and 0.577?(18). The asymmetric unit consists of two cations and two anions. PMID:21201423

Sun, Zhi Hua; Fan, Jian Dong; Zhang, Guang Hui; Wang, Xin Qiang; Xu, Dong

2008-01-01

425

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

426

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

427

Corrosion of Stainless Steel During Acetate Production  

Microsoft Academic Search

Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CHâCOOH under the process conditions commonly practiced in industry. The corrosive action of the

J. S. Qi; G. C. Lester

1996-01-01

428

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

429

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

430

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

431

Effects of nitrobenzene and zinc on acetate utilizing methanogens  

Microsoft Academic Search

Determination of anaerobic degradation rates and toxic effects of nitrobenzene (NB) on acetate utilizing methanogens was the first objective of this research. Serum bottles were used for anaerobic toxicity assays with an acetate enrichment culture of methanogens. Ten mg\\/l of nitrobenzene did not inhibit total gas production in the acetate enrichment methanogenic culture. Twenty and thirty mg\\/l of nitrobenzene caused

Sanjoy K. Bhattacharya; Mingbo Qu; Richard L. Madura

1996-01-01

432

Thermochemical characteristics of cellulose acetates with different degrees of acetylation  

NASA Astrophysics Data System (ADS)

The standard enthalpies of combustion and formation of cellulose acetates with different degrees of acetylation are determined. It is established that there is a proportional dependence of these thermochemical characteristics vs. the degree of acetylation, weight fraction of bonded acetic acid, and molar mass of the repeating unit of cellulose acetates.

Larina, V. N.; Ur'yash, V. F.; Kushch, D. S.

2012-12-01

433

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

Microsoft Academic Search

Gallium (4wt%) doped ZnO (GZO) thin films were deposited on hydrothermally grown ZnO buffered and non-buffered MgAl2O4 (111) substrates by RF magnetron sputtering technique at a growth temperature of 250°C. The epitaxial ZnO buffer layer was deposited on the MgAl2O4 (111) substrate by a hydrothermal technique using aqueous solutions of zinc nitrate hexahydrate, ammonium nitrate and ammonium hydroxide at 90°C.

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

2011-01-01

434

Hydrogen bonding in hydrates with one acetic acid molecule.  

PubMed

Hydrogen bonding (H-bond) interaction significantly influences the separation of acetic acid (HAc) from the HAc/H(2)O mixtures, especially the dilute solution, in distillation processes. It has been examined from the HAc mono-, di-, tri-, and tetrahydrates by analyzing the structures, binding energies, and infrared vibrational frequencies from quantum chemical calculations. For the first coordinate shell the 6-membered head-on ring is surely the most favorable structure because it has (1) the most favorable H-bonding parameters, (2) almost the largest binding energy per H-bond, (3) the biggest wavenumber shifts, and (4) the highest ring distribution (the AIMD simulations). Moreover, the comparison of the calculations with the experiments (the X-ray scattering data and IR frequencies) suggests that the possible structures in dilute aqueous solution are those involving two or more coordinate shells. The H-bonding in these water-surrounded HAc hydrates are the origin of the low-efficiency problem of isolating HAc from the dilute HAc/H(2)O mixtures. It is apparently a tougher work to break the H-bonds among HAc and the surrounded H(2)O molecules with respect to the case of more concentrated solutions, where the dominant structures are HAc or H(2)O aggregates. PMID:20853886

Pu, Liang; Sun, Yueming; Zhang, Zhibing

2010-10-14

435

Coupled Ca2+/H+ transport by cytoplasmic buffers regulates local Ca2+ and H+ ion signaling  

PubMed Central

Ca2+ signaling regulates cell function. This is subject to modulation by H+ ions that are universal end-products of metabolism. Due to slow diffusion and common buffers, changes in cytoplasmic [Ca2+] ([Ca2+]i) or [H+] ([H+]i) can become compartmentalized, leading potentially to complex spatial Ca2+/H+ coupling. This was studied by fluorescence imaging of cardiac myocytes. An increase in [H+]i, produced by superfusion of acetate (salt of membrane-permeant weak acid), evoked a [Ca2+]i rise, independent of sarcolemmal Ca2+ influx or release from mitochondria, sarcoplasmic reticulum, or acidic stores. Photolytic H+ uncaging from 2-nitrobenzaldehyde also raised [Ca2+]i, and the yield was reduced following inhibition of glycolysis or mitochondrial respiration. H+ uncaging into buffer mixtures in vitro demonstrated that Ca2+ unloading from proteins, histidyl dipeptides (HDPs; e.g., carnosine), and ATP can underlie the H+-evoked [Ca2+]i rise. Raising [H+]i tonically at one end of a myocyte evoked a local [Ca2+]i rise in the acidic microdomain, which did not dissipate. The result is consistent with uphill Ca2+ transport into the acidic zone via Ca2+/H+ exchange on diffusible HDPs and ATP molecules, energized by the [H+]i gradient. Ca2+ recruitment to a localized acid microdomain was greatly reduced during intracellular Mg2+ overload or by ATP depletion, maneuvers that reduce the Ca2+-carrying capacity of HDPs. Cytoplasmic HDPs and ATP underlie spatial Ca2+/H+ coupling in the cardiac myocyte by providing ion exchange and transport on common buffer sites. Given the abundance of cellular HDPs and ATP, spatial Ca2+/H+ coupling is likely to be of general importance in cell signaling. PMID:23676270

Swietach, Pawel; Youm, Jae-Boum; Saegusa, Noriko; Leem, Chae-Hun; Spitzer, Kenneth W.; Vaughan-Jones, Richard D.

2013-01-01

436

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

437

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

438

Hofmeister specific-ion effects on enzyme activity and buffer pH: Horseradish peroxidase in citrate buffer  

Microsoft Academic Search

Salt addition to enzymes in buffer always induce the problem of the respective influences of electrostatic interactions and anion specificity on buffer pH and enzyme kinetics. In the present paper the influence of some sodium salts (Na2SO4, NaCl, NaBr and NaNO3) on the pH of a citrate buffer (c=0.025 M), and on the catalytic constants of horseradish peroxidase (HRP) is

Pierre Bauduin; Fawaz Nohmie; Didier Touraud; Roland Neueder; Werner Kunz; Barry W. Ninham

2006-01-01

439

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

440

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

441

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

442

Pathways of Human Sprawl in Wilderness Buffer Zones  

Microsoft Academic Search

Intensification of human sprawl in buffer zones of globally important African wilderness areas is of worldwide concern. The paper identifies two major conflicting (yet potentially reconcilable) pathways of rural sprawl in African wilderness buffer regions, described as the subsistence pathway and the wildlife-tourism pathway. Containment of rural sprawl near important ecological reserves requires addressing both pathways and their underlying conflicts.

Cornelis Vanderpost

2006-01-01

443

Pseudodepth in the Z-buffer CSC 418 Tutorial  

E-print Network

Pseudodepth in the Z-buffer CSC 418 Tutorial Friday February 13, 2004 Recall the Z-buffer algorithm divide? Denote it Q = [Qx, Qy, Q, 1] Using pseudodepth during scan conversion: When scan converting transformation of each fragment. As a single example, consider the scan conversion code for a horizontal line (P0

Toronto, University of

444

Adipose tissue as a buffer for daily lipid flux  

Microsoft Academic Search

Insulin resistance occurs in obesity and Type II (non-insulin-dependent) diabetes mellitus, but it is also a prominent feature of lipodystrophy. Adipose tissue could play a crucial part in buffering the flux of fatty acids in the circulation in the postprandial period, analogous to the roles of the liver and skeletal muscle in buffering postprandial glucose fluxes. Adipose tissue provides its

K. N. Frayn

2002-01-01

445

Online scheduling with a buffer on related machines Gyorgy Dosa  

E-print Network

of jobs arriving one by one (also called over list) is a basic model in online scheduling [18]. The systemOnline scheduling with a buffer on related machines Gy¨orgy D´osa Leah Epstein Abstract Online scheduling with a buffer is a semi-online problem which is strongly related to the basic online scheduling

Epstein, Leah

446

Characterization of A Shared Buffer Optoelectronic Packet Router  

E-print Network

Characterization of A Shared Buffer Optoelectronic Packet Router Shunyuan Ye, Marina Thottan, Jesse.simsarian}@alcatel-lucent.com, panwar@catt.poly.edu Abstract--The rapid increase in Internet traffic is forcing packet routers to grow in capacity to meet the demand. Optical packet routers with less buffering and a greater degree of optical

Panwar, Shivendra S.

447

Part III: Routers with very small buffers Mihaela Enachescu  

E-print Network

Part III: Routers with very small buffers Mihaela Enachescu Department of Computer Science Stanford Roughgarden Department of Computer Science Stanford University tim@cs.stanford.edu ABSTRACT Internet routers. Unfortunately, a widely used rule-of-thumb says we need a bandwidth-delay product of buffering at each router so

Ganjali, Yashar

448

Variable-Size Multipacket Segments in Buffered Crossbar (CICQ) Architectures  

E-print Network

this is not feasible, segmentation and reassembly (SAR) must be used. We propose a novel SAR scheme for buffered scheme using simulation, and show that it outperforms existing segmentation schemes in buffered as well with segmentation and reassembly (SAR), thus also eliminating egress queueing, and, overall, greatly reducing cost

Katevenis, Manolis G.H.

449

VariableSize Multipacket Segments in Buffered Crossbar (CICQ) Architectures  

E-print Network

this is not feasible, segmentation and reassembly (SAR) must be used. We propose a novel SAR scheme for buffered scheme using simulation, and show that it outperforms existing segmentation schemes in buffered as well with segmentation and reassembly (SAR), thus also eliminating egress queueing, and, overall, greatly reducing cost

Katevenis, Manolis G.H.

450

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

451

SLOB: a switch with large optical buffers for packet switching  

Microsoft Academic Search

Recently, optical packet switch architectures, composed of devices such as optical switches, fiber delay lines, and passive couplers, have been proposed to overcome the electromagnetic interference (EMI), pinout and interconnection problems that would be encountered in future large electronic switch cores. However, attaining the buffer size (buffer depth) in optical packet switches required in practice is a major problem; in

David K. Hunter; W. David Cornwell; Tim H. Gilfedder; A. Franzen; I. Andonovic

1998-01-01

452

Optimal Multiplexing on a Single Link: Delay and Buffer Requirements  

Microsoft Academic Search

This paper is motivated by the need to support multiple service classes in fast packet-switched networks. The authors address the problem of characterizing and designing scheduling policies that are optimal in the sense of minimizing buffer and\\/or delay requirements under the assumption of commonly accepted traffic constraints. They investigate the buffer requirements under three typical memory allocation mechanisms, that represent

Leonidas Georgiadis; Roch Guérin; Abhay K. Parekh

1994-01-01

453

An Optical Crosspoint Buffered Switching Architecture Lin Cai,1, 2  

E-print Network

& Networks, Pecking University, China Abstract - We propose an optical crosspoint buffered switching fabric to simplify the implementation of optical packet switches. With the proposed switching fabric architecture of the critical components of optical packet switching. Current optical buffers are mainly based on fiber delay

Wai, Ping-kong Alexander

454

Buffer overflow management in QoS switches  

Microsoft Academic Search

We consider two types of buffering policies that are used in network switches supporting QoS (Quality of Service). In the FIFO type, packets must be released in the order they arrive; the difficulty in this case is the limited buffer space. In the bounded-delay type, each packet has a maximum delay time by which it must be released, or otherwise

Alexander Kesselman; Zvi Lotker; Yishay Mansour; Boaz Patt-Shamir; Baruch Schieber; Maxim Sviridenko

2001-01-01

455

Wasco Riparian Buffer Project, Annual Report 2003-2004  

Microsoft Academic Search

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

Graves; Ron

2003-01-01

456

General Conference.(Part B) A FINITE BUFFER QUEUE  

E-print Network

the buffer sizelimits the amountof work that canbe stored in the queue. The arrival process is a Poisson or a Markov mod- ulated Poisson process. The service times (packet lengths) are iid with a general and the probability of packet loss. Key Words:Finite buffer queue, MMPP arrival process. 1. Introduction In this paper

Sharma, Vinod

457

Job Stress and the Buffering Effect of Supervisory Support  

Microsoft Academic Search

This investigation examined the buffering model of social support with respect to the moderating effect of supervisory support on the relationship between job stress and job dissatisfaction for 96 employed graduate and undergraduate business students. Although a cross-sectional design was employed, results are consistent with the hypothesis that supervisory support acts as a stress buffer only for individuals who are

Robert C. Cummins

1990-01-01

458

Comparative shell buffering properties correlate with anoxia tolerance in freshwater turtles.  

PubMed

Freshwater turtles as a group are more resistant to anoxia than other vertebrates, but some species, such as painted turtles, for reasons not fully understood, can remain anoxic at winter temperatures far longer than others. Because buffering of lactic acid by the shell of the painted turtle is crucial to its long-term anoxic survival, we have tested the hypothesis that previously described differences in anoxia tolerance of five species of North American freshwater turtles may be explained at least in part by differences in their shell composition and buffering capacity. All species tested have large mineralized shells. Shell comparisons included 1) total shell CO2 concentration, 2) volume of titrated acid required to hold incubating shell powder at pH 7.0 for 3 h (an indication of buffer release from shell), and 3) lactate concentration of shell samples incubated to equilibrium in a standard lactate solution. For each measurement, the more anoxia-tolerant species (painted turtle, Chrysemys picta; snapping turtle, Chelydra serpentina) had higher values than the less anoxia-tolerant species (musk turtle, Sternotherus odoratus; map turtle, Graptemys geographica; red-eared slider, Trachemys scripta). We suggest that greater concentrations of accessible CO2 (as carbonate or bicarbonate) in the more tolerant species enable these species, when acidotic, to release more buffer into the extracellular fluid and to take up more lactic acid into their shells. We conclude that the interspecific differences in shell composition and buffering can contribute to, but cannot explain fully, the variations observed in anoxia tolerance among freshwater turtles. PMID:17008457

Jackson, Donald C; Taylor, Sarah E; Asare, Vivian S; Villarnovo, Dania; Gall, Jonathan M; Reese, Scott A

2007-02-01

459

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

460

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

PubMed

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

461

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

462

Effects of aqueous buffers on electrocatalytic water oxidation with an iridium oxide material electrodeposited in thin layers from an organometallic precursor.  

PubMed

A thin layer of an amorphous, mixed-valence iridium oxide (electrodeposited from an organometallic precursor, [Cp*Ir(H(2)O)(3)](2+)) is a heterogeneous catalyst among the most active and stable currently available for electrochemical water oxidation. We show that buffers can improve the oxygen-evolution activity of such thin-layer catalysts near neutral pH, but that buffer identity and concentration, as well as the solution pH, remain key determinants of long-term electrocatalyst activity and stability; for example, phosphate buffer can reduce the overpotential by up to 173 mV. PMID:23292194

Kushner-Lenhoff, Maxwell N; Blakemore, James D; Schley, Nathan D; Crabtree, Robert H; Brudvig, Gary W

2013-03-14

463

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

464

Acetate supplementation attenuates lipopolysaccharide-induced neuroinflammation  

PubMed Central

Glyceryl triacetate (GTA), a compound effective at increasing circulating and tissue levels of acetate was used to treat rats subjected to a continual 28 day intra-ventricular infusion of bacterial lipopolysaccharide (LPS). This model produces a neuroinflammatory injury characterized by global neuroglial activation and a decrease in choline acetyltransferase immunoreactivity in the basal forebrain. During the LPS infusion, rats were given a daily treatment of either water or GTA at a dose of 6g/kg by oral gavage. In parallel experiments free-CoA and acetyl-CoA levels were measured in microwave fixed brains and flash frozen heart, liver, kidney and muscle following a single oral dose of GTA. We found that a single oral dose of GTA significantly increased plasma acetate levels by 15 min and remained elevated for up to 4 hr. At 30 min the acetyl-CoA levels in microwave-fixed brain and flash frozen heart and liver were increased at least 2.2-fold. The concentrations of brain acetyl-CoA was significantly increased between 30 and 45 min following treatment and remained elevated for up to 4 hr. The concentration of free-CoA in brain was significantly decreased compared to controls at 240 min. Immunohistochemical and morphological analysis demonstrated that a daily treatment with GTA significantly reduced the percentage of reactive GFAP-positive astrocytes and activated CD11b-positive microglia by 40–50% in rats subjected to LPS-induced neuroinflammation. Further, in rats subjected to neuroinflammation, GTA significantly increased the number of ChAT-positive cells by 40% in the basal forebrain compared to untreated controls. These data suggest that acetate supplementation increases intermediary short chain acetyl-CoA metabolism and that treatment is potentially anti-inflammatory and neuroprotective with regards to attenuating neuroglial activation and increasing ChAT immunoreactivity in this model. PMID:21272004

Reisenauer, Chris J.; Bhatt, Dhaval P.; Mitteness, Dane J.; Slanczka, Evan R.; Gienger, Heidi M.; Watt, John A.; Rosenberger, Thad A.

2011-01-01

465

Solvation model for acetic acid in binary mixtures of cyclohexane–1,2-dichloroethane  

Microsoft Academic Search

The partition of acetic acid between aqueous solutions and various binary mixtures of 1,2-dichloroethane and cyclohexane were studied at 30.0°C. The observed nonlinearities of both monomer partition coefficient and dimerization constant in the organic phase with the mole fraction of 1,2-dichloroethane are interpreted in terms of the preferential solvation of various solvation sites of the involved species. Two polar sites

A. I. Abu-Shady; H. F. Al-Mudhaf; M. F. Hegazi

2004-01-01

466

Antimicrobial and antioxidant effects of sodium acetate, sodium lactate, and sodium citrate in refrigerated sliced salmon  

Microsoft Academic Search

This study was carried out to evaluate the microbiological quality and lipid oxidation of fresh salmon slices treated by dipping in 2.5% (w\\/v) aqueous solution of sodium acetate (NaA), sodium lactate (NaL), or sodium citrate (NaC) and stored at 1°C. The results revealed that these salts were efficient (P<0.05) against the proliferation of various categories of spoilage microorganisms; including aerobic

Khalid Ibrahim Sallam

2007-01-01

467

2-Amino-pyridinium trifluoro-acetate.  

PubMed

The asymmetric unit of the title compound, C(5)H(7)N(2) (+)·C(2)F(3)O(2) (-), contains four independent 2-amino-pyridinium cations and four independent trifluoro-acetate anions. In the crystal structure, these ions are linked by N-H?O hydrogen bonds, forming four cation-anion pairs each containing an R(2) (2)(8) ring motif. The ion pairs are linked into two independent chains along [100] by N-H?O hydrogen bonds. In addition, C-H?O and C-H?F hydrogen bonds and ??? inter-actions [centoid-centroid separation = 3.6007?(17)?Å] are observed. PMID:21580433

Hemamalini, Madhukar; Fun, Hoong-Kun

2010-01-01

468

Cd 0.5Zn 0.5Se wide range composite thin films for solar cell buffer layer application  

NASA Astrophysics Data System (ADS)

Cd 0.5Zn 0.5Se composite thin films were obtained on glass substrate using aqueous alkaline solution at low temperature using cadmium acetate and zinc acetate as Cd 2+ and Zn 2+ and Se 2- ion sources. Different phases of individuals i.e. CdSe and ZnSe, spherical and needle shape surface morphology and good elemental chemical stoichiometric ratio were observed from X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) studies, respectively. The band gap and electrical resistivity of the composite film were 2.35 eV and about 10 7 ? cm, respectively.

Kale, R. B.; Lokhande, C. D.; Mane, R. S.; Han, Sung-Hwan

2007-01-01

469

Nitrogen dynamics among cropland and riparian buffers: soil-landscape influences.  

PubMed

Nitrate (NO3-) leaching to ground water poses water quality concerns in some settings. Riparian buffers have been advocated to reduce excess ground water NO3- concentrations. We characterized inorganic N in soil solution and shallow ground water for 16 paired cropland-riparian plots from 2003 to 2005. The sites were located at two private dairy farms in Central New York on silt and gravelly silt loam soils (Aeric Endoaqualfs, Fluvaquentic Endoaquepts, Fluvaquentic Eutrudepts, Glossaquic Hapludalfs, and Glossic Hapludalfs). It was hypothesized that cropland N inputs and soil-landscape variability would jointly affect NO3- leaching and transformations in ground water. Results showed that well and moderately well drained fields had consistently higher ground water NO3- compared to more imperfectly drained fields receiving comparable N inputs. Average 50-cm depth soil solution NO3- and ground water dissolved oxygen (DO) explained 64% of average cropland ground water NO3- variability. Cropland ground water with an average DO of <3 mg L(-1) tended to have <4 mg L(-1) of NO3- with a water table depth (WTD) of buffers. More poorly drained buffers had low ground water NO3- and DO, a shallow WTD, and higher ground water ammonium and soil organic matter. Chloride patterns indicated that dilution was minor in most buffers, suggesting that denitrification losses were important. Soil-landscape factors strongly influenced NO3- behavior and suggest the importance of accurately characterizing soil variability along cropland-riparian zones. PMID:17485712

Young, Eric O; Briggs, Russell D

2007-01-01

470

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

471

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

472

Influence of the second buffer layer for alignment of seed film on Ni tape with NiO buffer layer  

NASA Astrophysics Data System (ADS)

In order to investigate the influence of the buffer layer for the seed film quality which is important to obtain high quality liquid phase epitaxy film, we prepared several different kinds of SmBa 2Cu 3O y (Sm123) seed films on SOE-NiO buffered biaxially textured Ni tapes with and without the second buffer layer of BaZrO 3 by the pulsed laser deposition method. As a consequence of the investigation, it was found that BaZrO 3 is a suitable material as a buffer layer to obtain highly in-plane aligned Sm123 seed films on SOE-NiO buffered biaxially textured Ni tapes.

Kai, M.; Izumi, T.; Hasegawa, K.; Tokunaga, Y.; Asada, S.; Nakamura, Y.; Izumi, T.; Watanabe, T.; Shiohara, Y.

2002-10-01

473

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 c