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1

Investigation on isobaric vapor liquid equilibrium for acetic acid + water + ( n-propyl acetate or iso-butyl acetate)  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data for acetic acid+water, acetic acid+n-propyl acetate, acetic acid+iso-butyl acetate, acetic acid+water+n-propyl acetate, acetic acid+water+iso-butyl acetate are measured at 101.33kPa with a modified Rose still. The nonideal behavior in vapor phase caused by the association of acetic acid are corrected by the chemical theory and Hayden–O’Connell method, and analyzed by calculating the second virial coefficients and

Chundong Zhang; Hui Wan; Lijun Xue; Guofeng Guan

2011-01-01

2

Cytenamide acetic acid solvate  

PubMed Central

In the crystal structure of the title compound (systematic name: 5H-dibenzo[a,d]cyclo­hepta­triene-5-carboxamide ethanoic acid solvate), C16H13NO·C2H4O2, the cytenamide and solvent mol­ecules form a hydrogen-bonded R 2 2(8) dimer motif, which is further connected to form a centrosymmetric double ring motif arrangement. The cycloheptene ring adopts a boat conformation and the dihedral angle between the least-squares planes through the two aromatic rings is 54.7?(2)°.

Johnston, Andrea; Florence, Alastair J.; Fabianni, Francesca J. A.; Shankland, Kenneth; Bedford, Colin T.

2008-01-01

3

Investigation on isobaric vapor–liquid equilibrium for acetic acid + water + methyl ethyl ketone + isopropyl acetate  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data for acetic acid+water, acetic acid+methyl ethyl ketone (MEK), MEK+isopropyl acetate, acetic acid+MEK+water and acetic acid+MEK+isopropyl acetate+water are measured at 101.33kPa using a modified Rose cell. The nonideal behavior in vapor phase of binary systems measured in this work is analyzed through calculating fugacity coefficients since mixture containing acetic acid deviates from ideal behavior seriously in

Qiang Xie; Hui Wan; MingJuan Han; GuoFeng Guan

2009-01-01

4

Oxidative reaction of oxindole-3-acetic acids.  

PubMed

The oxindole-3-acetic acids, oxidative metabolites of indole-3-acetic acid, were isolated from a byproduct of a corn starch manufacturing plant, and were further converted to the 3-hydroxyl derivatives in the presence of metal ion. The mechanical study was followed by a chemical analysis including other byproducts, and suggested the presence of an intermediate that had a radical at the C-3 position of oxindole-3-acetic acids. PMID:14519969

Niwa, Toshio; Ishii, Sayuri; Hiramatsu, Atsushi; Osawa, Toshihiko

2003-09-01

5

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

6

Atmospheric oxidation pathways of acetic acid.  

PubMed

One of the most abundant carboxylic acids measured in the atmosphere is acetic acid (CH(3)C(O)OH), present in rural, urban, and remote marine environments in the low-ppb range. Acetic acid concentrations are not well reproduced in global 3-D atmospheric models because of the poor inventory of sources and sinks to model its global distribution. To understand the complete oxidation of acetic acid in the atmosphere initiated by OH radicals, ab initio calculations are performed to describe in detail the energetics of the reaction potential energy surface (PES). The proposed reaction mechanism suggests that the CH(3)C(O)OH + OH reaction takes place via three pathways: the addition of OH to the central carbon, the abstraction of a methyl hydrogen, and the abstraction of an acidic hydrogen. The PES is characterized by prereactive H-complexes, transition states, and more interestingly unique radical-mediated isomerization reactions. From the analysis of the energetics, acetic acid atmospheric oxidation will proceed mainly via the abstraction of the acidic hydrogen, consistent with previous experimental and theoretical studies. The major byproducts from each pathway are identified. Glyoxylic acid is suggested to be a major byproduct of the atmospheric oxidation of acetic acid. The atmospheric fate of glyoxylic acid is discussed. PMID:16571046

Rosado-Reyes, Claudette M; Francisco, Joseph S

2006-04-01

7

Genera and species in acetic acid bacteria.  

PubMed

Taxonomic studies of acetic acid bacteria were historically surveyed. The genus Acetobacter was first introduced in 1898 with a single species, Acetobacter aceti. The genus Gluconobacter was proposed in 1935 for strains with intense oxidation of glucose to gluconic acid rather than oxidation of ethanol to acetic acid and no oxidation of acetate. The genus "Acetomonas" was described in 1954 for strains with polar flagellation and no oxidation of acetate. The proposals of the two generic names were due to confusion, and "Acetomonas" was a junior subjective synonym of Gluconobacter. The genus Acetobacter was in 1984 divided into two subgenera, Acetobacter and Gluconoacetobacter. The latter was elevated to the genus Gluconacetobacter in 1998. In the acetic acid bacteria, ten genera are presently recognized and accommodated to the family Acetobacteraceae, the Alphaproteobacteria: Acetobacteer, Gluconobacter, Acidomonas, Gluconacetobacter, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia and Granulibacter. In contrast, the genus Frateuria, strains of which were once named 'pseudacetic acid bacteria', was classified into the Gammaproteobacteria. The genus Gluconacetobacter was phylogenetically divided into two groups: the Gluconacetobacter liquefaciens group and the Gluconacetobacter xylinus group. The two groups were discussed taxonomically. PMID:18199517

Yamada, Yuzo; Yukphan, Pattaraporn

2008-06-30

8

Dynamic Protonation Equilibrium of Solvated Acetic Acid  

SciTech Connect

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

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

2007-04-13

9

Cytenamide trifluoro-acetic acid solvate  

PubMed Central

Cytenamide forms a 1:1 solvate with trifluoro­acetic acid (systematic name: 5H-dibenzo[a,d]cyclo­hepta­triene-5-carboxamide trifluoro­acetic acid solvate), C16H13NO·C2HF3O2. The compound crystallizes with one mol­ecule of cytenamide and one of trifluoro­acetic acid in the asymmetric unit; these are linked by O—H?O and N—H?O hydrogen bonds to form an R 2 2(8) motif. The trifluoro­methyl group of the solvent mol­ecule displays rotational disorder over two sites, with site-occupancy factors of 0.964?(4) and 0.036?(4).

Johnston, Andrea; Florence, Alastair J.; Fabbiani, Francesca J. A.; Shankland, Kenneth; Bedford, Colin T.; Bardin, Julie

2008-01-01

10

Polypyrrole based strong acid catalyst for acetalization  

NASA Astrophysics Data System (ADS)

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

Liang, Xuezheng; Cheng, Yuxiao; Qi, Chenze

2011-09-01

11

Acetic acid vapor levels associated with facial prosthetics  

SciTech Connect

The use of Silastic Medical Adhesive Type A in the fabrication of facial prostheses may cause health hazards to the patient and the operator because of acetic acid emissions. Caution must be exercised to remove acetic acid vapors from the air and unliberated acetic acid from material applied directly to the skin.

McElroy, T.H.; Guerra, O.N.; Lee, S.A.

1985-01-01

12

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

ERIC Educational Resources Information Center

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

Donahue, Craig J.; Panek, Mary G.

1985-01-01

13

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

14

Atmospheric formic and acetic acids: An overview  

NASA Astrophysics Data System (ADS)

Interest in the role of organic acids as chemical constituents in troposphere has been growing rapidly over the past couple of decades. In addition to their presence in the atmosphere in a variety of phases, organic acids are important constituents of the global troposphere and contribute a large fraction (˜25%) to the nonmethane hydrocarbon atmospheric mixture. They contribute significantly to the acidity of precipitation and cloud water, especially in remote regions. In this review, we consider the information presently available on concentration distribution of formic and acetic acids in multiple phases and their sources in different geographical locations, i.e., midlatitude continental, tropical continental and marine sites. Photochemical reactions (i.e., ozone-olefin reaction, isoprene oxidation, gas phase reaction of formaldehyde with HO2, and aqueous phase oxidation of formaldehyde) are important sources of these acids. In midlatitude continental regions, possible sources of formic and acetic acids, in addition to photochemical reactive vehicular emission, are direct emission from vegetation and biomass burning. In tropical continental sites, direct emission from vehicles, ants, soil, vegetation, and biomass burning are the important source of these species. The probable sources at marine locations are photochemical reactions, biogenic emissions, and long-range transport from continental sites.

Khare, Puja; Kumar, N.; Kumari, K. M.; Srivastava, S. S.

1999-05-01

15

Correlation of vapor - liquid equilibrium data for acetic acid - isopropanol - water - isopropyl acetate mixtures  

Microsoft Academic Search

A correlation procedure for the prediction of vapor - liquid equilibrium of acetic acid - isopropanol - water - isopropyl acetate mixtures has been developed. It is based on the NRTL model for predicting liquid activity coefficients, and on the Hayden-O'Connell second virial coefficients for predicting the vapor phase of systems containing association components. When compared with experimental data the

E. A. Campanella

2006-01-01

16

Determination of Indole Acetic Acid by the Salkowsky Reaction  

Microsoft Academic Search

RECENTLY attention has been focused on the reaction of indole acetic acid with ferric ions. Cohen et al.1 have shown that indole acetic acid forms a chelate with iron at acid pH and this has been confirmed by Recaldin and Heath2. The latter state that at pH 2.6 iron slowly decomposes the indole acetic acid in the solution. The oxidation

A. M. Mayer

1958-01-01

17

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

NASA Astrophysics Data System (ADS)

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

McCollom, Thomas M.; Seewald, Jeffrey S.

2003-10-01

18

Ultrasonic Relaxation in Aqueous Acetic Acid Solutions.  

National Technical Information Service (NTIS)

Ultrasonic absorption measurements have been made in aqueous acetic solutions at 15 to 85 MHz using pulse echo and pulse send-receive techniques. A weighted nonlinear regression method has been developed for the computation of the relaxation parameters. A...

L. G. Jackopin E. Yeager

1971-01-01

19

Indole-3-acetic Acid in Douglas Fir  

PubMed Central

We sought evidence for the occurrence and seasonal variation of indole-3-acetic acid (IAA) in shoots of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco). Collections obtained in December and June were extracted with methanol and diethyl ether. Extracts were purified by solvent partitioning and with Sephadex LH-20. Qualitative and quantitative information was acquired by gas-liquid chromatography of methyl, trimethylsilyl, or both derivatives of plant extract components. Analysis was performed with polar (XE-60) and moderately polar (Hi-Eff-8-BP) stationary phases. Results from three collections demonstrated that IAA does occur in Douglas fir and that amounts vary seasonally. Mass analysis of the proposed endogenous IAA peak from two representative extracts supported gas-liquid chromatography data and established the presence of IAA in Douglas fir.

Deyoe, David R.; Zaerr, Joe B.

1976-01-01

20

Recovery of acetic acid from waste streams by extractive distillation.  

PubMed

Wastes have been considered to be a serious worldwide environmental problem in recent years. Because of increasing pollution, these wastes should be treated. However, industrial wastes can contain a number of valuable organic components. Recovery of these components is important economically. Using conventional distillation techniques, the separation of acetic acid and water is both impractical and uneconomical, because it often requires large number of trays and a high reflux ratio. In practice special techniques are used depending on the concentration of acetic acid. Between 30 and 70% (w/w) acetic acid contents, extractive distillation was suggested. Extractive distillation is a multicomponent-rectification method similar in purpose to azeotropic distillation. In extractive distillation, to a binary mixture which is difficult or impossible to separate by ordinary means, a third component termed an entrainer is added which alters the relative volatility of the original constituents, thus permitting the separation. In our department acetic acid is used as a solvent during the obtaining of cobalt(III) acetate from cobalt(II) acetate by an electrochemical method. After the operation, the remaining waste contains acetic acid. In thiswork, acetic acid which has been found in this waste was recovered by extractive distillation. Adiponitrile and sulfolane were used as high boiling solvents and the effects of solvent feed rate/solution feed rate ratio and type were investigated. According to the experimental results, it was seem that the recovery of acetic acid from waste streams is possible by extractive distillation. PMID:12862234

Demiral, H; Yildirim, M Ercengiz

2003-01-01

21

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

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

22

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

PubMed Central

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

Reinecke, Dennis M.; Bandurski, Robert S.

1988-01-01

23

Acetic acid production by Dekkera\\/Brettanomyces yeasts  

Microsoft Academic Search

Yeast belonging to the genera Brettanomyces and Dekkera are noted for spoiling cellar and bottled wine through the production of haze, turbidity and acetic acid. However, I was unable to find information on the use of these yeasts for the expressed purpose of acetic acid production. Sixty yeast strains belonging to these, and several other genera, from the ARS Culture

S. N. Freer

2002-01-01

24

Cloud Point Extraction of Acetic Acid from Aqueous Solution  

Microsoft Academic Search

A new acetic acid separation method was developed through a successful combination of cloud point extraction and complex extraction technology (CPE-SE), where an acetic acid complex compound formed and was solubilized in a surfactant micelle solution, instead of an organic solvent, and then concentrated into one phase by a phase separation process of the CPE technology. Since no organic solvent

Bingjia Yao; Li Yang

2009-01-01

25

Measurement of the rates of oxindole-3-acetic acid turnover, and indole-3-acetic acid oxidation in Zea mays seedlings  

NASA Technical Reports Server (NTRS)

Oxindole-3-acetic acid is the principal catabolite of indole-3-acetic acid in Zea mays seedlings. In this paper measurements of the turnover of oxindole-3-acetic acid are presented and used to calculate the rate of indole-3-acetic acid oxidation. [3H]Oxindole-3-acetic acid was applied to the endosperm of Zea mays seedlings and allowed to equilibrate for 24 h before the start of the experiment. The subsequent decrease in its specific activity was used to calculate the turnover rate. The average half-life of oxindole-3-acetic acid in the shoots was found to be 30 h while that in the kernels had an average half-life of 35h. Using previously published values of the pool sizes of oxindole-3-acetic acid in shoots and kernels from seedlings of the same age and variety, and grown under the same conditions, the rate of indole-3-acetic acid oxidation was calculated to be 1.1 pmol plant-1 h-1 in the shoots and 7.1 pmol plant-1 h-1 in the kernels.

Nonhebel, H. M.; Bandurski, R. S. (Principal Investigator)

1986-01-01

26

Oxidation of indole-3-acetic acid and oxindole-3-acetic acid to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glucopyranoside in Zea mays seedlings  

NASA Technical Reports Server (NTRS)

Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid --> Oxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid-glucoside.

Nonhebel, H. M.; Bandurski, R. S.

1984-01-01

27

Oxidation of Indole-3-acetic Acid and Oxindole-3-acetic Acid to 2,3-Dihydro-7-hydroxy-2-oxo-1H Indole-3-acetic Acid-7?-O-?-d-Glucopyranoside in Zea mays Seedlings 1  

PubMed Central

Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7?-O-?-d-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid ? Oxindole-3-acetic acid ? 7-Hydroxyoxindole-3-acetic acid ? 7-Hydroxyoxindole-3-acetic acid-glucoside.

Nonhebel, Heather M.; Bandurski, Robert S.

1984-01-01

28

Computerized image analysis for acetic acid induced intraepithelial lesions  

NASA Astrophysics Data System (ADS)

Cervical Intraepithelial Neoplasia (CIN) exhibits certain morphologic features that can be identified during a visual inspection exam. Immature and dysphasic cervical squamous epithelium turns white after application of acetic acid during the exam. The whitening process occurs visually over several minutes and subjectively discriminates between dysphasic and normal tissue. Digital imaging technologies allow us to assist the physician analyzing the acetic acid induced lesions (acetowhite region) in a fully automatic way. This paper reports a study designed to measure multiple parameters of the acetowhitening process from two images captured with a digital colposcope. One image is captured before the acetic acid application, and the other is captured after the acetic acid application. The spatial change of the acetowhitening is extracted using color and texture information in the post acetic acid image; the temporal change is extracted from the intensity and color changes between the post acetic acid and pre acetic acid images with an automatic alignment. The imaging and data analysis system has been evaluated with a total of 99 human subjects and demonstrate its potential to screening underserved women where access to skilled colposcopists is limited.

Li, Wenjing; Ferris, Daron G.; Lieberman, Rich W.

2008-04-01

29

40 CFR 721.10448 - Acetic acid, hydroxy- methoxy-, methyl ester, reaction products with substituted alkylamine...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Acetic acid, hydroxy- methoxy-, methyl...Substances § 721.10448 Acetic acid, hydroxy- methoxy-, methyl...identified generically as acetic acid, hydroxymethoxy-, methyl...substance according to the average number molecular weight section...

2013-07-01

30

The antibacterial activity and stability of acetic acid.  

PubMed

Acetic acid has been shown to have good antibacterial activity against micro-organisms such as Pseudomonas aeruginosa. This study examined the activity against a range of bacterial pathogens and also assessed any reduction in antibacterial activity due to evaporation or inactivation by organic material in dressings. Acetic acid was active at dilutions as low as 0.166% and the activity was not reduced by evaporation nor by inactivation by cotton swabs. Burn injuries are a major problem in countries with limited resources. Acetic acid is an ideal candidate for use in patients who are treated in those parts of the world. PMID:23747099

Fraise, A P; Wilkinson, M A C; Bradley, C R; Oppenheim, B; Moiemen, N

2013-08-01

31

Conversion of acetic acid to methane by thermophiles: Progress report.  

National Technical Information Service (NTIS)

The objective of this project is to provide an understanding of thermophilic anaerobic microorganisms capable of breaking down acetic acid, the precursor of two-thirds of the methane produced by anaerobic bioreactors. Recent results include: (1) the isola...

S. Zinder

1991-01-01

32

SOLVENT EXTRACTION OF WASTEWATERS FROM ACETIC-ACID MANUFACTURE  

EPA Science Inventory

Solvent extraction was evaluated as a potential treatment method for wastewaters generated during the manufacture of acetic acid. Possible goals for an extraction process were considered. For the wastewater samples studied, extraction appeared to be too expensive to be practical ...

33

Liquid-liquid equilibria of the ternary systems water + acetic acid + ethyl acetate and water + acetic acid + isophorene (3,5,5-trimethyl-2-cyclohexen-1-one)  

SciTech Connect

Liquid-liquid equilibria for the ternary systems water + acetic acid + ethyl acetate and water + acetic acid + isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) were measured over the temperature range (283 to 313) K. The results were used to estimate the interaction parameters between each of the three compounds of the systems studied for the NRTL and UNIQUAC models. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models; experimental data were successfully reproduced. The UNIQUAC model was the most accurate in correlating the overall equilibrium composition of the studied systems. Also the NRTL model satisfactorily predicted the equilibrium composition. Isophorone experimentally resulted in a better extraction capacity for acetic acid and in a lower miscibility with water.

Colombo, A.; Battilana, P.; Ragaini, V.; Bianchi, C.L. [Milan Univ. (Italy). Dept. of Physical Chemistry and Electrochemistry] [Milan Univ. (Italy). Dept. of Physical Chemistry and Electrochemistry; Carvoli, G. [Chemial S.p.A., Cavaglia (Italy)] [Chemial S.p.A., Cavaglia (Italy)

1999-01-01

34

Hydrothermal production of formic and acetic acids from syringol  

Microsoft Academic Search

The production of formic and acetic acids (or salts) by hydrothermal oxidation of syringol, a model compound for lignin, was\\u000a investigated using a batch reactor. Results show that the highest yields of formic and acetic acids were, respectively, 59.6%\\u000a and 11.3% at the reaction condition of 0.5 mol\\/L NaOH, 120% H2O2 supply and 280 °C. These results will inform studies

Lu-ting Pan; Zheng Shen; Lei Wu; Ya-lei Zhang; Xue-fei Zhou; Fang-ming Jin

2010-01-01

35

Tetrazole acetic acid: tautomers, conformers, and isomerization.  

PubMed

Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0-8 kJ mol(-1) energy range and should be appreciably populated at the sublimation temperature (?330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol(-1)) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol(-1)). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm(-1), where the first OH stretching overtone vibrations of 1ccc and 2pcc occur. The reverse transformations could be induced by irradiations at 7010 and 7030 cm(-1), transforming 1cct and 2pct back to 1ccc and 2pcc, also selectively. Besides the NIR-induced transformations, the photogenerated 1cct and 2pct forms also decay in N2 matrices back to 1ccc and 2pcc spontaneously, with characteristic decay times of hours (1H) and tens of minutes (2H). The decay mechanism is rationalized in terms of the proton tunneling. In crystals, TAA exists exclusively as 1H-tautomer. By contrast, the tautomeric composition of the matrix-isolated monomers was found to consist of both 1H- and 2H-tautomers, in comparable amounts. A mechanistic discussion of the tautomerization process occurring during sublimation, accounting also for the observed minor decomposition of TAA leading to CO2 and 5-methyl-tetrazole, is proposed. PMID:24527914

Araujo-Andrade, C; Reva, I; Fausto, R

2014-02-14

36

Tetrazole acetic acid: Tautomers, conformers, and isomerization  

NASA Astrophysics Data System (ADS)

Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0-8 kJ mol-1 energy range and should be appreciably populated at the sublimation temperature (˜330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol-1) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol-1). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm-1, where the first OH stretching overtone vibrations of 1ccc and 2pcc occur. The reverse transformations could be induced by irradiations at 7010 and 7030 cm-1, transforming 1cct and 2pct back to 1ccc and 2pcc, also selectively. Besides the NIR-induced transformations, the photogenerated 1cct and 2pct forms also decay in N2 matrices back to 1ccc and 2pcc spontaneously, with characteristic decay times of hours (1H) and tens of minutes (2H). The decay mechanism is rationalized in terms of the proton tunneling. In crystals, TAA exists exclusively as 1H-tautomer. By contrast, the tautomeric composition of the matrix-isolated monomers was found to consist of both 1H- and 2H-tautomers, in comparable amounts. A mechanistic discussion of the tautomerization process occurring during sublimation, accounting also for the observed minor decomposition of TAA leading to CO2 and 5-methyl-tetrazole, is proposed.

Araujo-Andrade, C.; Reva, I.; Fausto, R.

2014-02-01

37

Toughening of poly(lactic acid) by ethylene- co-vinyl acetate copolymer with different vinyl acetate contents  

Microsoft Academic Search

The well-known bio-based and biocompostable poly(lactic acid), PLA, suffers from brittleness and a low heat distortion temperature. In this paper, we address a possible route to make PLA tough(er) by blending with ethylene-co-vinyl acetate (EVA) with different vinyl acetate contents. The compatibility and phase morphology of the PLA\\/EVA blends was controlled by the ratio of vinyl acetate and ethylene in

P. Ma; D. G. Hristova-Bogaerds; J. G. P. Goossens; Y. Zhang; P. J. Lemstra

2012-01-01

38

Characterization of acetic acid bacteria in "traditional balsamic vinegar".  

PubMed

This study evaluated the glucose tolerance of acetic acid bacteria strains isolated from Traditional Balsamic Vinegar. The results showed that the greatest hurdle to acetic acid bacteria growth is the high sugar concentration, since the majority of the isolated strains are inhibited by 25% of glucose. Sugar tolerance is an important technological trait because Traditional Balsamic Vinegar is made with concentrated cooked must. On the contrary, ethanol concentration of the cooked and fermented must is less significant for acetic acid bacteria growth. A tentative identification of the isolated strains was done by 16S-23S-5S rDNA PCR/RFLP technique and the isolated strains were clustered: 32 strains belong to Gluconacetobacter xylinus group, two strains to Acetobacter pasteurianus group and one to Acetobacter aceti. PMID:16214251

Gullo, Maria; Caggia, Cinzia; De Vero, Luciana; Giudici, Paolo

2006-02-01

39

Abiraterone acetate.  

PubMed

Abiraterone acetate (CB 7630; CB7630; JNJ-212082), the 3?-acetate prodrug of abiraterone, is structurally related to ketoconazole and is being developed by Cougar Biotechnology as a hormonal therapy for advanced prostate and breast cancers. As a selective inhibitor of adrenal androgens, it is thought to be a safer product than existing second-line hormonal therapies. This review discusses the key development milestones and therapeutic trials of this drug. PMID:21171672

2010-01-01

40

The effect of oral sodium acetate administration on plasma acetate concentration and acid-base state in horses  

PubMed Central

Aim Sodium acetate (NaAcetate) has received some attention as an alkalinizing agent and possible alternative energy source for the horse, however the effects of oral administration remain largely unknown. The present study used the physicochemical approach to characterize the changes in acid-base status occurring after oral NaAcetate/acetic acid (NAA) administration in horses. Methods Jugular venous blood was sampled from 9 exercise-conditioned horses on 2 separate occasions, at rest and for 24 h following a competition exercise test (CET) designed to simulate the speed and endurance test of 3-day event. Immediately after the CETs horses were allowed water ad libitum and either: 1) 8 L of a hypertonic NaAcetate/acetic acid solution via nasogastric tube followed by a typical hay/grain meal (NAA trial); or 2) a hay/grain meal alone (Control trial). Results Oral NAA resulted in a profound plasma alkalosis marked by decreased plasma [H+] and increased plasma [TCO2] and [HCO3-] compared to Control. The primary contributor to the plasma alkalosis was an increased [SID], as a result of increased plasma [Na+] and decreased plasma [Cl-]. An increased [Atot], due to increased [PP] and a sustained increase in plasma [acetate], contributed a minor acidifying effect. Conclusion It is concluded that oral NaAcetate could be used as both an alkalinizing agent and an alternative energy source in the horse.

Waller, Amanda; Lindinger, Michael I

2007-01-01

41

[Conversion of acetic acid to methane by thermophiles  

SciTech Connect

The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

Zinder, S.H.

1993-01-01

42

Acetic acid: Microwave spectra, internal rotation and substitution structure  

Microsoft Academic Search

The internal rotation splittings in the microwave spectrum of acetic acid have been re-examined, using both principal axis method (PAM) and internal axis method (IAM) treatments. It is shown how individual terms in the PAM equation can be correlated to the first terms in an expansion of the corresponding IAM formula. When centrifugal distortion was allowed for, both methods reproduced

B. P. van Eijck; J. van Opheusden; M. M. M. van Schaik; E. van Zoeren

1981-01-01

43

Mass Spectral and Electric Deflection Study of Acetic Acid Clusters.  

National Technical Information Service (NTIS)

Acetic acid clusters, (CH3COOH)n, up to n = 10, were produced in a supersonic beam expansion and analyzed in a molecular beam quadrupole mass spectrometer. A general mechanism for their mass spectral fragmentation was deduced. Polarity of the first four c...

R. Sivert I. Cadez J. Van Doren A. W. Castleman

1984-01-01

44

Occurrence and metabolism of 7-hydroxy-2-indolinone-3-acetic acid in Zea mays  

NASA Technical Reports Server (NTRS)

7-Hydroxy-2-indolinone-3-acetic acid was identified as a catabolite of indole-3-acetic acid in germinating kernels of Zea mays and found to be present in amounts of ca 3.1 nmol/kernel. 7-Hydroxy-2-indolinone-3-acetic acid was shown to be a biosynthetic intermediate between 2-indolinone-3-acetic acid and 7-hydroxy-2-indolinone-3-acetic acid-7'-O-glucoside in both kernels and roots of Zea mays. Further metabolism of 7-hydroxy-2-[5-3H]-indolinone-3-acetic acid-7'-O-glucoside occurred to yield tritiated water plus, as yet, uncharacterized products.

Lewer, P.; Bandurski, R. S.

1987-01-01

45

Production of acetic acid from methanol by thermophilic Methanosarcina sp.: Acetate production as an index in abnormal methane fermentation  

Microsoft Academic Search

Production of approximately 80–160 ?mol of acetic acid was observed in 1% (w\\/w) methanol culture media (10 ml) of thermophilic Methanosarcina sp. from which essential nutrients such as salts of NH4+, PO43?, K+, Ca2+ and Mg2+ were removed. Similar acetic acid production was found when methane gas formation was controlled to approximately 50% by means of inhibitors of methyl group

Makoto Yamaguchi; Kiyoshi Minami

1998-01-01

46

CARCINOGENICITY OF THE CHLORINATED ACETIC ACIDS  

EPA Science Inventory

Dichloroacetic Acid (DCAA) and trichloroacetic acid (TCAA) comprise a major fraction of the reaction products formed when water containing a variety of precursor humic materials is chlorinated. Both DCAA and TCAA administered in the drinking water increased the incidence of hepat...

47

21 CFR 184.1005 - Acetic acid.  

Code of Federal Regulations, 2013 CFR

...64-19-7) is known as ethanoic acid. It occurs naturally in plant and animal tissues. It is produced by fermentation of...170.3(n)(24) of this chapter; 0.6 percent for meat products as defined in § 170.3(n)(29) of this...

2013-04-01

48

3-Acet-oxy-2-naphthoic acid.  

PubMed

In the title compound, C(13)H(10)O(4), an analog of acetyl-salicylic acid, the naphthalene unit is twisted slightly due to ortho disubstitution [dihedral angle between conjugated rings system in the naphthalene unit = 2.0?(2)°]. The mean planes of the carb-oxy-lic and ester groups are almost coplanar and perpendicular, respectively, to the mean plane of the conjugated aromatic system, making dihedral angles of 8.9?(3) and 89.3?(1)°. In the crystal, mol-ecules are paired through their carb-oxy-lic groups by the typical centrosymmetric O-H?O inter-actions with R(2) (2)(8) hydrogen-bond motifs. In addition, several weak C-H?O inter-molecular contacts are also observed. Finally, the mol-ecules are stacked along crystallographic [100] and [010] directions. PMID:21589033

Souza, Bruno S; Vitto, Ramon; Nome, Faruk; Kirby, Anthony J; Bortoluzzi, Adailton J

2010-01-01

49

40 CFR 721.304 - Acetic acid, [(5-chloro-8-quinolinyl)oxy-], 1-methyl hexyl ester.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Acetic acid, [(5-chloro-8-quinolinyl...Specific Chemical Substances § 721.304 Acetic acid, [(5-chloro-8-quinolinyl...The chemical substance identified as acetic acid,...

2010-07-01

50

40 CFR 721.304 - Acetic acid, [(5-chloro-8-quinolinyl)oxy-], 1-methyl hexyl ester.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Acetic acid, [(5-chloro-8-quinolinyl...Specific Chemical Substances § 721.304 Acetic acid, [(5-chloro-8-quinolinyl...The chemical substance identified as acetic acid,...

2009-07-01

51

Structured catalysts for photo-Fenton oxidation of acetic acid  

Microsoft Academic Search

In this work photo-Fenton oxidation of acetic acid, was carried out on perovskites based structured catalysts, in the presence or in the absence of low amounts of Pt. Homogeneous photo-Fenton reaction by ferrioxalate complex has been also performed. The comparison of homogeneous and heterogeneous photo-Fenton oxidation indicates that the use of a heterogeneous structured catalyst greatly improves the total organic

Diana Sannino; Vincenzo Vaiano; Paolo Ciambelli; Lyubov A. Isupova

2011-01-01

52

Adaptive cytoprotection against acetic acid induced colonic injury in rats  

Microsoft Academic Search

Background and aims: The phenomenon of prostaglandin dependent adaptive cytoprotection has been well established in the stomach and duodenum but not in the colon. This study investigated whether it also occurs in the colon. Methods: Fisher rats received intracolonic administration (0.5 ml) of saline or acetic acid at low concentrations (0.01-5%) followed by high concentration (25%) at various intervals (10-720

Toru Kono; Masashi Yoneda; Kei Ohara; Tokiyoshi Ayabe; Naoyuki Chisato; Yutaka Kohgo; Shinichi Kasai; Akira Terano; Yvette Taché

2001-01-01

53

Potential energy surfaces for proton abstractions from acetic acid  

Microsoft Academic Search

The abstractions of hydrogen from both carbon and oxygen in acetic acid by hydride, fluoride, and hydroxide anions have been studied using ab initio electronic structure calculations. Molecular structures were optimized at the Hartree-Fock level of theory using the 6-31++G(d,p) basis set. For energetics, the 6-311++G(d,p) basis set was used, with second- and fourth-order perturbation theory corrections, for both minima

Mark S. Gordon; David R. Gano; Eugene Curtiss

1996-01-01

54

Photocatalytic oxidation and decomposition of acetic acid on titanium silicalite.  

PubMed

Transient reaction of adsorbed monolayers of acetic acid was used to characterize the photocatalytic properties of titanium silicalite zeolites (TS-1). The TS-1 zeolites having Si/Ti ratios of 5, 12.5, and 50 are effective catalysts at room temperature for both photocatalytic oxidation (PCO) and decomposition (PCD) of acetic acid. The rates of PCO are higher than the rates of PCD for each catalyst. Acetic acid oxidized photocatalytically in 0.2% O2 to form gas-phase CO2 and CH4 and adsorbed H2O on the TS-1 catalysts, whereas no CH4 formed on Degussa P25 TiO2. Isotope labeling showed that, on both TiO2 and TS-1 catalysts, the alpha-carbon formed CO2 whereas the beta-carbon formed CH4 and CO2. The rates of oxidation of the two carbons have different dependencies on UV intensity. The catalysts with higher Si/Ti ratios adsorbed significantly more acetic acid, and the PCO rates per gram of titanium are highest on the TS-1 catalyst with the lowest Ti content, apparently because a larger fraction of the Ti atoms are surface atoms on this catalyst. During PCD in an inert atmosphere, CO2, CH4, and C2H6 formed on TiO2 and on the catalyst with a Si/Ti ratio of 5, but C2H6 was not detected on the other catalysts. The CO2/CH4 selectivity during PCD increased with increasing Si/Ti ratio. The first step in PCO and PCD on TS-1 catalysts appears to be similar and involves formation of a CH3 radical. PMID:11347941

Lee, G D; Tuan, V A; Falconer, J L

2001-03-15

55

Catalysis of the Carbonylation of Alcohols to Carboxylic Acids Including Acetic Acid Synthesis from Methanol.  

ERIC Educational Resources Information Center

Monsanto's highly successful synthesis of acetic acid from methanol and carbon monoxide illustrates use of new starting materials to replace pretroleum-derived ethylene. Outlines the fundamental aspects of the acetic acid process and suggests ways of extending the synthesis to higher carboxylic acids. (JN)

Forster, Denis; DeKleva, Thomas W.

1986-01-01

56

Indole-3-acetic acid in plant-microbe interactions.  

PubMed

Indole-3-acetic acid (IAA) is an important phytohormone with the capacity to control plant development in both beneficial and deleterious ways. The ability to synthesize IAA is an attribute that many bacteria including both plant growth-promoters and phytopathogens possess. There are three main pathways through which IAA is synthesized; the indole-3-pyruvic acid, indole-3-acetamide and indole-3-acetonitrile pathways. This chapter reviews the factors that effect the production of this phytohormone, the role of IAA in bacterial physiology and in plant-microbe interactions including phytostimulation and phytopathogenesis. PMID:24445491

Duca, Daiana; Lorv, Janet; Patten, Cheryl L; Rose, David; Glick, Bernard R

2014-07-01

57

Preparation of vinyl acetate  

DOEpatents

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

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

1998-01-01

58

Preparation of vinyl acetate  

DOEpatents

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

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

1998-03-24

59

Kinetic Modeling of Esterification of Ethylene Glycol with Acetic Acid  

NASA Astrophysics Data System (ADS)

The reaction kinetics of the esterification of ethylene glycol with acetic acid in the presence of cation exchange resin has been studied and kinetic models based on empirical and Langmuir approach has been developed. The Langmuir based model involving eight kinetic parameters fits experimental data much better compared to empirical model involving four kinetic parameters. The effect of temperature and catalyst loading on the reaction system has been analyzed. Further, the activation energy and frequency factor of the rate constants for Langmuir based model has been estimated.

Yadav, Vishnu P.; Mukherjee, Rudra Palash; Bantraj, Kandi; Maity, Sunil K.

2010-10-01

60

Indole 3-acetic acid production by ectomycorrhizal fungi.  

PubMed

Ability of 8 ectomycorrhizal fungi to synthesise indole 3-acetic acid from L-tryptophan and their growth rate were studied. Differences in the levels of IAA synthesis and biomass production among the 8 mycorrhizal fungi were observed. A positive correlation was recorded between IAA level and mycelial growth. The synthesis of IAA and mycelial biomass were maximum on 30th day after incubation. Pisolithus tinctorius and Laccaria laccata exhibited higher amounts of IAA production than other fungi, whereas Amanita muscaria and Rhizopogon luteolus showed least quantity of IAA. PMID:1521864

Gopinathan, S; Raman, N

1992-02-01

61

Polymerization of vinyl acetate in fatty acids and properties of poly (vinyl alcohols) derived from the poly (vinyl acetates)  

Microsoft Academic Search

Polymerization of vinyl acetate (VAc) in various fatty acids (carbon numbers 4–18) was carried out. Chain transfer constants to the acids were determined to be 20–35×10-4, from which the constant to a methylene group was obtained to be 0.73×10-4. Viscometry in aqueous solution of derived poly (vinyl alcohol) (PVA) showed the usual behavior in terms of Huggins’ constant obtained by

Takeshi Ishijima; Yoshiki Mizumori; Kenji Kikuchi; Atsushi Suzuki; Takuji Okaya

2005-01-01

62

Nanoporous In2O3-based cataluminescence sensor for acetic acid vapor  

Microsoft Academic Search

In the present paper, we reported a cataluminescence (CTL) sensor using nanoporous In2O3 as sensing material to determine trace acetic acid in air. The proposed sensor showed high sensitivity and selectivity to acetic acid at optimal temperature of 293degC. Quantitative analysis was performed at a wavelength of 440 nm. The linear range of CTL intensity versus concentration of acetic acid

Xiaoan Cao; Yanqin Hu; Ying Tao

2008-01-01

63

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

Microsoft Academic Search

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

Justine Criquet; Nathalie Karpel Vel Leitner

2009-01-01

64

Recent advances in nitrogen-fixing acetic acid bacteria.  

PubMed

Nitrogen is an essential plant nutrient, widely applied as N-fertilizer to improve yield of agriculturally important crops. An interesting alternative to avoid or reduce the use of N-fertilizers could be the exploitation of plant growth-promoting bacteria (PGPB), capable of enhancing growth and yield of many plant species, several of agronomic and ecological significance. PGPB belong to diverse genera, including Azospirillum, Azotobacter, Herbaspirillum, Bacillus, Burkholderia, Pseudomonas, Rhizobium, and Gluconacetobacter, among others. They are capable of promoting plant growth through different mechanisms including (in some cases), the biological nitrogen fixation (BNF), the enzymatic reduction of the atmospheric dinitrogen (N(2)) to ammonia, catalyzed by nitrogenase. Aerobic bacteria able to oxidize ethanol to acetic acid in neutral or acid media are candidates of belonging to the family Acetobacteraceae. At present, this family has been divided into ten genera: Acetobacter, Gluconacetobacter, Gluconobacter, Acidomonas, Asaia, Kozakia, Saccharibacter, Swaminathania, Neoasaia, and Granulibacter. Among them, only three genera include N(2)-fixing species: Gluconacetobacter, Swaminathania and Acetobacter. The first N(2)-fixing acetic acid bacterium (AAB) was described in Brazil. It was found inside tissues of the sugarcane plant, and first named as Acetobacter diazotrophicus, but then renamed as Gluconacetobacter diazotrophicus. Later, two new species within the genus Gluconacetobacter, associated to coffee plants, were described in Mexico: G. johannae and G. azotocaptans. A salt-tolerant bacterium named Swaminathania salitolerans was found associated to wild rice plants. Recently, N(2)-fixing Acetobacter peroxydans and Acetobacter nitrogenifigens, associated with rice plants and Kombucha tea, respectively, were described in India. In this paper, recent advances involving nitrogen-fixing AAB are presented. Their natural habitats, physiological and genetic aspects, as well as their association with different plants and contribution through BNF are described as an overview. PMID:18177965

Pedraza, Raúl O

2008-06-30

65

Acetic acid and aromatics units planned in China  

SciTech Connect

The Shanghai Wujing Chemical Complex (SWCC; Shanghai) is proceeding with construction of an acetic acid plant. The 100,000-m.t./year until will use BP Chemicals carbonylation technology, originally developed by Monsanto. John Brown has been selected by China National Technical Import Corp. (CNTIC) to supply the plant, Chinese sources say. The UK contractor, which competed against Mitsui Engineering Shipbuilding (Tokyo) and Lurgi (Frankfurt), has built a similar plant for BP in the UK, although using different technology. The new plant will require 54,000 m.t./year of methanol, which is available onsite. Carbon monoxide will be delivered from a new plant. The acetic acid unit will joint two other acetic plants in China supplied some time ago by Uhde (Dortmund). SWCC is due to be integrated with two adjacent complexes to form Shanghai Pacific Chemical. Meanwhile, four groups are competing to supply a UOP-process aromatics complex for Jilin Chemical Industrial Corp. They are Toyo Engineering, Lurgi, Lucky/Foster Wheeler, and Eurotechnica. The complex will include plants with annual capacities for 115,000 m.t. of benzene, 90,000 m.t. of ortho-xylene, 93,000 m.t. of mixed xylenes, and 20,000 m.t. of toluene. The plants will form part of a $2-billion petrochemical complex based on a 300,000-m.t./year ethylene plant awarded last year to a consortium of Samsung Engineering and Linde. Downstream plants will have annual capacities for 120,000 m.t. of linear low-density polyethylene, 80,000 m.t. of ethylene oxide, 100,000 m.t. of ethylene glycol, 80,000 m.t. of phenol, 100,000 m.t. of acrylonitrile, 20,000 m.t. of sodium cyanide, 40,000 m.t. of phthalic anhydride, 40,000 m.t. of ethylene propylene rubber, 20,000 m.t. of styrene butadiene styrene, and 30,000 m.t. of acrylic fiber.

Alperowicz, N.

1993-01-27

66

Spectrophotometric Dissociation Field Effect Kinetics of Aqueous Acetic Acid and Bromocresol Green.  

National Technical Information Service (NTIS)

The acid-base dissociation kinetics of dilute aqueous acetic acid at 25C have been investigated using a square-wave dissociation field effect apparatus with spectrophotometric detection. The acetic acid equilibrium was coupled to that of a somewhat slower...

E. M. Eyring J. J. Auborn P. Warrick

1971-01-01

67

1 H and 13 C NMR observation of the reaction of acetic acid with titanium isopropoxide  

Microsoft Academic Search

Hydrogen and carbon NMR spectroscopy have been used to investigate the chemical modification process of titanium isopropoxide by acetic acid. The spectra confirm the belief that the titanium isopropoxide exchanges isopropyl groups with modifying acetate groups to form a molecule with approximate stoichiometry Ti(OiPr)2(OAc)2. This stoichiometry results even when enough acetic acid is present in solution to allow for significantly

Dunbar P Birnie III; Norbert J. Bendzko

1999-01-01

68

[Advances in functional genomics studies underlying acetic acid tolerance of Saccharomyces cerevisiae].  

PubMed

Industrial microorganisms are subject to various stress conditions, including products and substrates inhibitions. Therefore, improvement of stress tolerance is of great importance for industrial microbial production. Acetic acid is one of the major inhibitors in the cellulosic hydrolysates, which affects seriously on cell growth and metabolism of Saccharomyces cerevisiae. Studies on the molecular mechanisms underlying adaptive response and tolerance of acetic acid of S. cerevisiae benefit breeding of robust strains of industrial yeast for more efficient production. In recent years, more insights into the molecular mechanisms underlying acetic acid tolerance have been revealed through analysis of global gene expression and metabolomics analysis, as well as phenomics analysis by single gene deletion libraries. Novel genes related to response to acetic acid and improvement of acetic acid tolerance have been identified, and novel strains with improved acetic acid tolerance were constructed by modifying key genes. Metal ions including potassium and zinc play important roles in acetic acid tolerance in S. cerevisiae, and the effect of zinc was first discovered in our previous studies on flocculating yeast. Genes involved in cell wall remodeling, membrane transport, energy metabolism, amino acid biosynthesis and transport, as well as global transcription regulation were discussed. Exploration and modification of the molecular mechanisms of yeast acetic acid tolerance will be done further on levels such as post-translational modifications and synthetic biology and engineering; and the knowledge obtained will pave the way for breeding robust strains for more efficient bioconversion of cellulosic materials to produce biofuels and bio-based chemicals. PMID:25007573

Zhao, Xinqing; Zhang, Mingming; Xu, Guihong; Xu, Jianren; Bai, Fengwu

2014-03-01

69

Esters of Indole-3-Acetic Acid from Avena Seeds 1  

PubMed Central

The present studies showed that about 80% of the indole-3-acetic acid extractable from Avena kernels by aqueous acetone was esterified to polymers precipitable by ammonium sulfate and ethanol or acetone. The polymers were positively charged, being adsorbed to cation exchange columns at a pH of 3, or below, and eluted at a pH greater than 4. The polymers were heterogeneous with respect to size, about 5,000 to 20,000 daltons, and charge, exhibiting apparent pKa values of 4.2 and 4.7. The polymer fractions contained esterified IAA, anthrone-reactive material that liberated glucose upon acid hydrolysis, phenolic compounds, and peptidic material with a high proportion of hydrophobic amino acids. Since the esterified IAA was unstable, establishing polymer purity was not possible, and the designation IAA-glucoprotein fraction was adopted. Dehusked Avena kernels contained 8 mg/kg total IAA of which 5.5% was free and 94.5% esterified. IAA bound through a peptidic linkage was present, but in only trace amounts.

Percival, Frank W.; Bandurski, Robert S.

1976-01-01

70

Atmospheric geochemistry of formic and acetic acids at a mid-latitude temperate site  

NASA Technical Reports Server (NTRS)

Tropospheric concentrations of formic and acetic acids in the gas, the aerosol, and the rainwater phases were determined in samples collected 1-2 m above ground level at an open field site in eastern Virginia. These acids were found to occur principally (98 percent or above) in the gas phase, with a marked annual seasonality, averaging 1890 ppt for formate and 1310 ppt for acetate during the growing season, as compared to 695 ppt and 700 ppt, respectively, over the nongrowing season. The data support the hypothesis that biogenic emissions from vegatation are important sources of atmospheric formic and acetic acid during the local growing season. The same time trends were observed for precipitation, although with less defined seasonality. The relative increase of the acetic acid/formic acid ratio during the nongrowing season points to the dominance of anthropogenic inputs of acetic acid from motor vehicles and biomass combustion in the wintertime.

Talbot, R. W.; Beecher, K. M.; Harriss, R. C.; Cofer, R. W., III

1988-01-01

71

Acetic acid: Microwave spectra, internal rotation and substitution structure  

NASA Astrophysics Data System (ADS)

The internal rotation splittings in the microwave spectrum of acetic acid have been re-examined, using both principal axis method (PAM) and internal axis method (IAM) treatments. It is shown how individual terms in the PAM equation can be correlated to the first terms in an expansion of the corresponding IAM formula. When centrifugal distortion was allowed for, both methods reproduced the A-type frequencies within experimental error. For the E-type lines the r.m.s. deviation was 1.64 MHz in the PAM (using Wv? ( n) -terms with n = 1, 2, …, 14, d, e, f) and 0.70 MHz in the IAM. To derive the substitution structure eight isotopic species were studied. The inertial moments of the molecules with various degrees of methyl group deuteration are not consistent with each other, so these data could not be fully used. Therefore, the structure was derived with the assumption of a cylindrically symmetric methyl group, although there is some evidence that the HCH angles differ by a few degrees. The geometry, which is in agreement with earlier electron diffraction results, is compared with the substitution structures of other carboxylic acids.

van Eijck, B. P.; van Opheusden, J.; van Schaik, M. M. M.; van Zoeren, E.

1981-04-01

72

Formation of biologically relevant carboxylic acids during the gamma irradiation of acetic acid  

NASA Technical Reports Server (NTRS)

Irradiation of aqueous solutions of acetic acid with gamma rays produced several carboxylic acids in small yield. Their identification was based on the technique of gas chromatography combined with mass spectrometry. Some of these acids are Krebs Cycle intermediates. Their simultaneous formation in experiments simulating the primitive conditions on the earth suggests that metabolic pathways may have had their origin in prebiotic chemical processes.

Negron-Mendoza, A.; Ponnamperuma, C.

1976-01-01

73

Putative ABC Transporter Responsible for Acetic Acid Resistance in Acetobacter aceti  

PubMed Central

Two-dimensional gel electrophoretic analysis of the membrane fraction of Acetobacter aceti revealed the presence of several proteins that were produced in response to acetic acid. A 60-kDa protein, named AatA, which was mostly induced by acetic acid, was prepared; aatA was cloned on the basis of its NH2-terminal amino acid sequence. AatA, consisting of 591 amino acids and containing ATP-binding cassette (ABC) sequences and ABC signature sequences, belonged to the ABC transporter superfamily. The aatA mutation with an insertion of the neomycin resistance gene within the aatA coding region showed reduced resistance to acetic acid, formic acid, propionic acid, and lactic acid, whereas the aatA mutation exerted no effects on resistance to various drugs, growth at low pH (adjusted with HCl), assimilation of acetic acid, or resistance to citric acid. Introduction of plasmid pABC101 containing aatA under the control of the Escherichia coli lac promoter into the aatA mutant restored the defect in acetic acid resistance. In addition, pABC101 conferred acetic acid resistance on E. coli. These findings showed that AatA was a putative ABC transporter conferring acetic acid resistance on the host cell. Southern blot analysis and subsequent nucleotide sequencing predicted the presence of aatA orthologues in a variety of acetic acid bacteria belonging to the genera Acetobacter and Gluconacetobacter. The fermentation with A. aceti containing aatA on a multicopy plasmid resulted in an increase in the final yield of acetic acid.

Nakano, Shigeru; Fukaya, Masahiro; Horinouchi, Sueharu

2006-01-01

74

Production of Formic Acid and Acetic Acid by Hydrothermal Oxidation of Alkali Lignin  

NASA Astrophysics Data System (ADS)

The production of formic acid and acetic acid by hydrothermal oxidation of alkali lignin, a kind of biomasses, was investigated using a batch reactor with H2O2 oxidant. Experiments were performed over a wide range of conditions with temperature varying from 260 to 320° C, oxygen supply varying from 60% to 120%, and reaction time varying from 30 to 150 s. The highest yield of formic acid was 4.9% at 280° C for 120 s with the additive ratio of H2O2 100%. The highest value of acetic acid was 12.3% at 300° C for 120 s with the additive ratio of H2O2 100%. Based on the intermediate products identified by GC/MS and HPLC, reaction pathways of alkali lignin are discussed. It was found that maleic acid and fumaric acid were two primary unsaturated intermediate products. The production of formic acid and acetic acid were come from the oxidative decomposition of intermediate products in the oxidation process. Increasing the formation of saturated dicarboxylic acids and glutaconic acid would enhance the acetic acid yield.

Zeng, Xu; Jin, Fangming; Cao, Jianglin; Yin, Guodong; Zhang, Yalei; Zhao, Jianfu

2010-11-01

75

Radioimmunoassay of 5-hydroxyindole acetic acid using an iodinated derivative  

SciTech Connect

A radioimmunoassay for the main catabolite of serotonin, 5-hydroxyindole acetic acid (5-HIAA), was developed by using specific antibodies and iodinated derivative. The synthesis of a /sup 125/I-iodinated analog was performed by coupling 5-HIAA to (125I-)glycyl-tyrosine without any contact between 5-HIAA and iodine or chloramine T. It was purified on a G25 Sephadex column and diluted in citrate buffer up to 2.5 X 10(5) cpm/ml. Antibodies were obtained by coupling 5-HIAA to human serum albumin with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and tested by equilibrium dialysis. After the third immunogen injection, the four rabbits gave antisera capable of binding 50% of iodinated 5-HIIA-glycyl-tyrosine at 1/2000 final dilution. A chemical conversion of the biological samples gives to the antigen molecules a better resemblance to the immunogen, thus conferring a 100-fold gain in specificity and sensitivity. This assay allows 5-HIAA to be determined in small amounts of tissue, blood, cerebrospinal fluid or perfusate without purification with a sensitivity threshold below 0.1 ng. Some applications in cat and rat are presented.

Puizillout, J.J.; Delaage, M.A.

1981-06-01

76

Acetic acid bacteria isolated from grapes of South Australian vineyards.  

PubMed

Acetic acid bacteria (AAB) diversity from healthy, mould-infected and rot-affected grapes collected from three vineyards of Adelaide Hills (South Australia) was analyzed by molecular typing and identification methods. Nine different AAB species were identified from the 624 isolates recovered: Four species from Gluconobacter genus, two from Asaia and one from Acetobacter were identified by the analysis of 16S rRNA gene and 16S-23S rRNA gene internal transcribed spacer. However, the identification of other isolates that were assigned as Asaia sp. and Ameyamaea chiangmaiensis required more analysis for a correct species classification. The species of Gluconobacter cerinus was the main one identified; while one genotype of Asaia siamensis presented the highest number of isolates. The number of colonies recovered and genotypes identified was strongly affected by the infection status of the grapes; the rot-affected with the highest number. However, the species diversity was similar in all the cases. High AAB diversity was detected with a specific genotype distribution for each vineyard. PMID:24681711

Mateo, E; Torija, M J; Mas, A; Bartowsky, E J

2014-05-16

77

Metabolic regulation of the plant hormone indole-3-acetic acid  

SciTech Connect

The phytohormone indole-3-acetic acid (IAA, auxin) is important for many aspects of plant growth, development and responses to the environment yet the routes to is biosynthesis and mechanisms for regulation of IAA levels remain important research questions. A critical issue concerning the biosynthesis if IAA in plants is that redundant pathways for IAA biosynthesis exist in plants. We showed that these redundant pathways and their relative contribution to net IAA production are under both developmental and environmental control. We worked on three fundamental problems related to how plants get their IAA: 1) An in vitro biochemical approach was used to define the tryptophan dependent pathway to IAA using maize endosperm, where relatively large amounts of IAA are produced over a short developmental period. Both a stable isotope dilution and a protein MS approach were used to identify intermediates and enzymes in the reactions. 2) We developed an in vitro system for analysis of tryptophan-independent IAA biosynthesis in maize seedlings and we used a metabolite profiling approach to isolate intermediates in this reaction. 3) Arabidopsis contains a small family of genes that encode potential indolepyruvate decarboxylase enzymes. We cloned these genes and studied plants that are mutant in these genes and that over-express each member in the family in terms of the level and route of IAA biosynthesis. Together, these allowed further development of a comprehensive picture of the pathways and regulatory components that are involved in IAA homeostasis in higher plants.

Jerry D. Cohen

2009-11-01

78

Pervaporation of acetic acid\\/water mixtures through carbon molecular sieve-filled PDMS membranes  

Microsoft Academic Search

The pervaporation process for acetic\\/water has been investigated with carbon molecular sieve (CMS)-filled polydimethylsiloxane (PDMS) membranes. The effects of feed temperature, feed acetic acid concentration and CMS content on the performance of the membranes have been studied. It is found that the addition of CMS can improve pervaporation behavior of PDMS membranes to some extent and greatly increases the strength

Lei Li; Zeyi Xiao; Zhibing Zhang; Shujuan Tan

2004-01-01

79

Effect of Acetic Acid Supplementation on Egg Quality Characteristics of Commercial Laying Hens during Hot Season  

Microsoft Academic Search

This study was conducted to determine the effects of acetic acid supplement at four levels (control, 200, 400 and 600-ppm in drinking water) on egg production and quality in commercial Brown Leghorn reared birds during the hot season (32°C). One hundred and sixty 30 week-old laying birds were randomly divided into 4 groups and subjected to four levels of acetic

I. T. Kadim; W. Al-Marzooqi; O. Mahgoub; A. Al-Jabri; S. K. Al-Waheebi

2008-01-01

80

Scaleable Production and Separation of Fermentation-Derived Acetic Acid. Final CRADA report.  

National Technical Information Service (NTIS)

Half of U.S. acetic acid production is used in manufacturing vinyl acetate monomer (VAM) and is economical only in very large production plants. Nearly 80% of the VAM is produced by methanol carbonylation, which requires high temperatures and exotic const...

S. W. Snyder

2010-01-01

81

21 CFR 862.1390 - 5-Hydroxyindole acetic acid/serotonin test system.  

Code of Federal Regulations, 2010 CFR

...acid/serotonin in urine. Measurements of 5-hydroxyindole acetic acid/serotonin are used in the diagnosis and treatment of carcinoid tumors of endocrine tissue. (b) Classification. Class I (general controls). The device is exempt from the...

2010-04-01

82

21 CFR 862.1390 - 5-Hydroxyindole acetic acid/serotonin test system.  

Code of Federal Regulations, 2010 CFR

...acid/serotonin in urine. Measurements of 5-hydroxyindole acetic acid/serotonin are used in the diagnosis and treatment of carcinoid tumors of endocrine tissue. (b) Classification. Class I (general controls). The device is exempt from the...

2009-04-01

83

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

PubMed

In this work, acetic acid was found as one promising substrate to improve xylose utilization by Gluconacetobacter xylinus CH001. Also, with the help of adding acetic acid into medium, the bacterial cellulose (BC) production by G. xylinus was increased significantly. In the medium containing 3 g l(-1) acetic acid, the optimal xylose concentration for BC production was 20 g l(-1). In the medium containing 20 g l(-1) xylose, the xylose utilization and BC production by G. xylinus were stimulated by acetic acid within certain concentration. The highest BC yield (1.35 ± 0.06 g l(-1)) was obtained in the medium containing 20 g l(-1) xylose and 3 g l(-1) acetic acid after 14 days. This value was 6.17-fold higher than the yield (0.21 ± 0.01 g l(-1)) in the medium only containing 20 g l(-1) xylose. The results analyzed by FE-SEM, FTIR, and XRD showed that acetic acid affected little on the microscopic morphology and physicochemical characteristics of BC. Base on the phenomenon observed, lignocellulosic acid hydrolysates (xylose and acetic acid are main carbon sources present in it) could be considered as one potential substrate for BC production. PMID:24891733

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

2014-09-01

84

Acetic Acid Bacteria, Newly Emerging Symbionts of Insects?  

PubMed Central

Recent research in microbe-insect symbiosis has shown that acetic acid bacteria (AAB) establish symbiotic relationships with several insects of the orders Diptera, Hymenoptera, Hemiptera, and Homoptera, all relying on sugar-based diets, such as nectars, fruit sugars, or phloem sap. To date, the fruit flies Drosophila melanogaster and Bactrocera oleae, mosquitoes of the genera Anopheles and Aedes, the honey bee Apis mellifera, the leafhopper Scaphoideus titanus, and the mealybug Saccharicoccus sacchari have been found to be associated with the bacterial genera Acetobacter, Gluconacetobacter, Gluconobacter, Asaia, and Saccharibacter and the novel genus Commensalibacter. AAB establish symbiotic associations with the insect midgut, a niche characterized by the availability of diet-derived carbohydrates and oxygen and by an acidic pH, selective factors that support AAB growth. AAB have been shown to actively colonize different insect tissues and organs, such as the epithelia of male and female reproductive organs, the Malpighian tubules, and the salivary glands. This complex topology of the symbiosis indicates that AAB possess the keys for passing through body barriers, allowing them to migrate to different organs of the host. Recently, AAB involvement in the regulation of innate immune system homeostasis of Drosophila has been shown, indicating a functional role in host survival. All of these lines of evidence indicate that AAB can play different roles in insect biology, not being restricted to the feeding habit of the host. The close association of AAB and their insect hosts has been confirmed by the demonstration of multiple modes of transmission between individuals and to their progeny that include vertical and horizontal transmission routes, comprising a venereal one. Taken together, the data indicate that AAB represent novel secondary symbionts of insects.

Crotti, Elena; Rizzi, Aurora; Chouaia, Bessem; Ricci, Irene; Favia, Guido; Alma, Alberto; Sacchi, Luciano; Bourtzis, Kostas; Mandrioli, Mauro; Cherif, Ameur; Bandi, Claudio; Daffonchio, Daniele

2010-01-01

85

Acetic acid bacteria in traditional balsamic vinegar: phenotypic traits relevant for starter cultures selection.  

PubMed

This review focuses on acetic acid bacteria in traditional balsamic vinegar process. Although several studies are available on acetic acid bacteria ecology, metabolism and nutritional requirements, their activity as well as their technological traits in homemade vinegars as traditional balsamic vinegar is not well known. The basic technology to oxidise cooked grape must to produce traditional balsamic vinegar is performed by the so called "seed-vinegar" that is a microbiologically undefined starter culture obtained from spontaneous acetification of previous raw material. Selected starter cultures are the main technological improvement in order to innovate traditional balsamic vinegar production but until now they are rarely applied. To develop acetic acid bacteria starter cultures, selection criteria have to take in account composition of raw material, acetic acid bacteria metabolic activities, applied technology and desired characteristics of the final product. For traditional balsamic vinegar, significative phenotypical traits of acetic acid bacteria have been highlighted. Basic traits are: ethanol preferred and efficient oxidation, fast rate of acetic acid production, tolerance to high concentration of acetic acid, no overoxidation and low pH resistance. Specific traits are tolerance to high sugar concentration and to a wide temperature range. Gluconacetobacter europaeus and Acetobacter malorum strains can be evaluated to develop selected starter cultures since they show one or more suitable characters. PMID:18177968

Gullo, Maria; Giudici, Paolo

2008-06-30

86

Acetic Acid Production by an Electrodialysis Fermentation Method with a Computerized Control System  

PubMed Central

In acetic acid fermentation by Acetobacter aceti, the acetic acid produced inhibits the production of acetic acid by this microorganism. To alleviate this inhibitory effect, we developed an electrodialysis fermentation method such that acetic acid is continuously removed from the broth. The fermentation unit has a computerized system for the control of the pH and the concentration of ethanol in the fermentation broth. The electrodialysis fermentation system resulted in improved cell growth and higher productivity over an extended period; the productivity exceeded that from non-pH-controlled fermentation. During electrodialysis fermentation in our system, 97.6 g of acetic acid was produced from 86.0 g of ethanol; the amount of acetic acid was about 2.4 times greater than that produced by non-pH-controlled fermentation (40.1 g of acetic acid produced from 33.8 g of ethanol). Maximum productivity of electrodialysis fermentation in our system was 2.13 g/h, a rate which was 1.35 times higher than that of non-pH-controlled fermentation (1.58 g/h).

Nomura, Yoshiyuki; Iwahara, Masayoshi; Hongo, Motoyoshi

1988-01-01

87

5-Fluoroindole-3-acetic acid: a prodrug activated by a peroxidase with potential for use in targeted cancer therapy  

Microsoft Academic Search

Indole-3-acetic acid and some derivatives are oxidized by horseradish peroxidase, forming a radical-cation that rapidly fragments (eliminating CO2) to form cytotoxic products. No toxicity is seen when either indole-3-acetic acid or horseradish peroxidase is incubated alone at concentrations that together form potent cytotoxins. Unexpectedly, 5-fluoroindole-3-acetic acid, which is oxidized by horseradish peroxidase compound I 10-fold more slowly than indole-3-acetic acid,

Lisa K Folkes; Olga Greco; Gabi U Dachs; Michael R. L Stratford; Peter Wardman

2002-01-01

88

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

89

Migration of ethylene glycol from polyethylene terephthalate bottles into 3% acetic acid.  

PubMed

Migration of ethylene glycol (EG) from polyethylene terephthalate (PET) bottles into the food simulate 3% acetic acid was studied using 32 fluid oz PET bottles filled with 3% acetic acid and stored at 32 degrees C for 6 months. Final concentration of EG in the 3% acetic acid migration solution was about 100 ppb, which is equivalent to about 94 microgram EG/bottle. A gas-liquid chromatographic procedure for quantitating EG was developed which is capable of measuring EG levels as low as 50 ppb in the migration solution. PMID:6448834

Kashtock, M; Breder, C V

1980-03-01

90

Corrosion inhibition of indole-3-acetic acid on mild steel in 0.5 M HCl  

Microsoft Academic Search

Corrosion inhibition of indole-3-acetic acid on mild steel in acidic medium (0.5M HCl) containing the desired amount of inhibitor has been investigated at different temperatures by using potentiodynamic polarization, electrochemical impedance spectroscopy, and polarization resistance measurements. The experimental results showed that corrosion potential shifted toward a more negative potential region in the presence of indole-3-acetic acid than that of blank

Gül?en Avci

2008-01-01

91

Indole-3-Acetic Acid Biosynthesis in Colletotrichum gloeosporioides f. sp. aeschynomene  

PubMed Central

We characterized the biosynthesis of indole-3-acetic acid by the mycoherbicide Colletotrichum gloeosporioides f. sp. aeschynomene. Auxin production was tryptophan dependent. Compounds from the indole-3-acetamide and indole-3-pyruvic acid pathways were detected in culture filtrates. Feeding experiments and in vitro assay confirmed the presence of both pathways. Indole-3-acetamide was the major pathway utilized by the fungus to produce indole-3-acetic acid in culture.

Robinson, M.; Riov, J.; Sharon, A.

1998-01-01

92

Biosynthesis of the Halogenated Auxin, 4-Chloroindole-3-Acetic Acid1[W][OA  

PubMed Central

Seeds of several agriculturally important legumes are rich sources of the only halogenated plant hormone, 4-chloroindole-3-acetic acid. However, the biosynthesis of this auxin is poorly understood. Here, we show that in pea (Pisum sativum) seeds, 4-chloroindole-3-acetic acid is synthesized via the novel intermediate 4-chloroindole-3-pyruvic acid, which is produced from 4-chlorotryptophan by two aminotransferases, TRYPTOPHAN AMINOTRANSFERASE RELATED1 and TRYPTOPHAN AMINOTRANSFERASE RELATED2. We characterize a tar2 mutant, obtained by Targeting Induced Local Lesions in Genomes, the seeds of which contain dramatically reduced 4-chloroindole-3-acetic acid levels as they mature. We also show that the widespread auxin, indole-3-acetic acid, is synthesized by a parallel pathway in pea.

Tivendale, Nathan D.; Davidson, Sandra E.; Davies, Noel W.; Smith, Jason A.; Dalmais, Marion; Bendahmane, Abdelhafid I.; Quittenden, Laura J.; Sutton, Lily; Bala, Raj K.; Le Signor, Christine; Thompson, Richard; Horne, James; Reid, James B.; Ross, John J.

2012-01-01

93

Environmental Risk Limits for Ethylene Diamine Tetra Acetic acid (EDTA)  

Microsoft Academic Search

In this report maximum permissible concentration (MPC) and negligible\\u000aconcentration (NC) in water are derived for Ethylene Diamine Tetra Acetic\\u000aacid (EDTA; CAS No. 64-02-8, EINECS No. 200-573-9), based on the EU\\u000arisk assessment report for this compound. The Maximum Permissible\\u000aConcentration (MPC) for the water compartment is 2.2 mg\\/l, and the\\u000aNegligible Concentration (NC) is 0.022 mg\\/l. Calculation of

Kalf DF; Hoop van den MAGT; Rila JP; Posthuma C; Traas TP

2007-01-01

94

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

95

Metabolic Regulation of the Plant Hormone Indole-3-Acetic Acid, (Final Report).  

National Technical Information Service (NTIS)

The phytohormone indole-3-acetic acid (IAA, auxin) is important for many aspects of plant growth, development and responses to the environment yet the routes to is biosynthesis and mechanisms for regulation of IAA levels remain important research question...

J. D. Cohen

2009-01-01

96

Apical dominance and the levels of indole acetic acid in Phaseolus lateral buds  

Microsoft Academic Search

Combined gas chromatography-mass spectrometry procedures have been used to establish that the indole acetic acid levels of lateral buds from Phaseolus seedlings rise following removal of the shoot apex.

J. R. Hillman; V. B. Math; G. C. Medlow

1977-01-01

97

Methods of Synthesizing and Using Derivatives of (2-(2-Aminioethoxy)Ethoxy) Acetic Acid.  

National Technical Information Service (NTIS)

A synthetic reaction to produce (2-(2-aminoethoxy)ethoxy) acetic acid (AEEA) derivatives. This synthetic reaction does not require isolation and purification of intermediates. The AEEA derivatives can be used to synthesize high load polystyrene-polyethyle...

J. V. Aldrich V. Kumar

2005-01-01

98

Isobaric vapor–liquid equilibria for water + acetic acid + ( N-methyl pyrrolidone or N-methyl acetamide)  

Microsoft Academic Search

Isobaric vapor–liquid equilibria (VLE) data for acetic acid+N-methyl pyrrolidone, acetic acid+N-methyl acetamide, water+acetic acid+N-methyl pyrrolidone, and water+acetic acid+N-methyl acetamide systems have been measured at 101.33kPa using a recirculating still. The nonideality of the vapor phase caused by the association of the acetic acid has been corrected by the chemical theory and Hayden–O’Connell method. The experimental binary data have been correlated

Weixian Chang; Hui Wan; Guofeng Guan; Huqing Yao

2006-01-01

99

Inhibition of phorbol myristate acetate and phytohemagglutinin stimulation of human lymphocytes by 13-cis-retinoic acid and ethyl etrinoate  

Microsoft Academic Search

Summary The retinol analogues 13-cis-retinoic acid and ethyl etrinoate inhibit the mitogenic activity of phorbol myristate acetate and phytohemagglutinin on human lymphocytes. This inhibitory effect is greater against the stimulation with phorbol myristate acetate than with phytohemagglutinin.

L. F. Skinnider; K. Giesbrecht

1981-01-01

100

Modification of maize starch by thermal processing in glacial acetic acid  

Microsoft Academic Search

Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) methods were used to determine if corn starch–glacial acetic acid mixtures can be melted and thermally processed at reasonable temperatures. DSC studies showed that the melting temperature of dry starch was reduced from about 280 to 180°C in the presence of >30% acetic acid. Glass transition temperatures varied from 110 to 40°C

R. L Shogren

2000-01-01

101

ANTI-INFLAMMATORY ACTIVITY OF PHYCOCYANIN EXTRACT IN ACETIC ACID-INDUCED COLITIS IN RATS  

Microsoft Academic Search

The anti-inflammatory effect of c -phycocyanin extract was studied in acetic acid-induced colitis in rats. Phycocyanin (150, 200 and 300 mg kg?1p.o.) was administered 30 min before induction of colitis with enema of 1 ml of 4% acetic acid per rat. Twenty-four hours later myeloperoxidase (MPO) activity was determined as well as histopathological and ultrastructural studies were carried out in

RICARDO GONZÁLEZ; SANDRA RODRÍGUEZ; ADDYS GONZÁLEZ; DIADELIS REMIREZ; NELSON MERINO

1999-01-01

102

Polycarboxylic acids containing acetal functions: calcium sequestering compounds based on oxidized carbohydrates  

Microsoft Academic Search

A number of polycarboxylic acids containing acetal functions have been prepared by a two-step oxidation of carbohydrates.\\u000a Their calcium sequestering behavior is compared with that of a series of model polycarboxylic acids. It is found that calcium\\u000a sequestration by oxidized carbohydrates is less than that by corresponding ether polycarboxylates, since (a) acetal oxygens\\u000a have a lower coordinating power than ether

M. S. Nieuwenhuizen; A. P. G. Kieboom; H. van Bekkum

1983-01-01

103

Control of magnesia–alumina properties by acetic acid in sol–gel synthesis  

Microsoft Academic Search

Sol–gel synthesis was used to prepare oxides of aluminum and magnesium from mixtures of Al(O–s-Bu)3 and Mg(O–Et)2, with the atomic ratio of Al to Mg being 4. The hydrolysis and condensation reactions were controlled by acetic acid in the absence of added water; the ratio R of acetic acid to aluminum alkoxide (R=[CH3COOH]\\/[Al(O–s-Bu)3]) was varied from 1 to 6. The

Saloua Rezgui; Bruce C Gates

1997-01-01

104

Accelerated ripening of Dhakki dates by artificial means: ripening by acetic acid and sodium chloride  

Microsoft Academic Search

The effectiveness of sodium chloride and acetic acid for initiation\\/acceleration of the ripening of Dhakki dates has been investigated. Each treatment was applied individually and\\/or in combined form at different proportions varying from 0.25% to 3.5% and 0.25% to 2.5% for sodium chloride and acetic acid respectively. Dhakki dates at the Doka stage were immersed in treatment solutions for 5min

Shahzada A. Saleem; Ahmad K. Baloch; Musa Kaleem Baloch; Waqar A. Baloch; Abdul Ghaffoor

2005-01-01

105

Large prebiotic molecules in space: photo-physics of acetic acid and its isomers  

Microsoft Academic Search

An increasing number of large molecules have been positively identified in\\u000aspace. Many of these molecules are of biological interest and thus provide\\u000ainsight into prebiotic organic chemistry in the protoplanetary nebula. Among\\u000athese molecules, acetic acid is of particular importance due to its structural\\u000aproximity to glycine, the simplest amino acid. We compute electronic and\\u000avibrational properties of acetic

Fabrizio Puletti; Giuliano Malloci; Giacomo Mulas; Cesare Cecchi-Pestellini

2009-01-01

106

Leaching of spent lead acid battery paste components by sodium citrate and acetic acid.  

PubMed

A sustainable method, with minimal pollution and low energy cost in comparison with the conventional smelting methods, is proposed for treating components of spent lead-acid battery pastes in aqueous organic acid(s). In this study, PbO, PbO2, and PbSO4, the three major components in a spent lead paste, were individually reacted with a mixture of aqueous sodium citrate and acetic acid solution. Pure lead citrate precursor of Pb3(C6H5O7)2 · 3H2O is the only product crystallized in each leaching experiment. Conditions were optimized for individual lead compounds which were then used as the basis for leaching real industrial spent paste. In this work, efficient leaching process is achieved and raw material cost is reduced by using aqueous sodium citrate and acetic acid, instead of aqueous sodium citrate and citric acid as reported in a pioneering hydrometallurgical method earlier. Acetic acid is not only cheaper than citric acid but is also more effective in aiding dissolution of the lead compounds thus speeding up the leaching process in comparison with citric acid. Lead citrate is readily crystallized from the aqueous solution due to its low solubility and can be combusted to directly produce leady oxide as a precursor for making new battery pastes. PMID:23500418

Zhu, Xinfeng; He, Xiong; Yang, Jiakuan; Gao, Linxia; Liu, Jianwen; Yang, Danni; Sun, Xiaojuan; Zhang, Wei; Wang, Qin; Kumar, R Vasant

2013-04-15

107

Chromoendoscopy of gastric adenoma using an acetic acid indigocarmine mixture  

PubMed Central

AIM: To investigate the usefulness of chromoendoscopy, using an acetic acid indigocarmine mixture (AIM), for gastric adenoma diagnosed by forceps biopsy. METHODS: A total of 54 lesions in 45 patients diagnosed as gastric adenoma by forceps biopsy were prospectively enrolled in this study and treated by endoscopic submucosal dissection (ESD) between January 2011 and January 2012. AIM-chromoendoscopy (AIM-CE) was performed followed by ESD. AIM solution was sprinkled and images were recorded every 30 s for 3 min. Clinical characteristics such as tumor size (< 2 cm, ? 2 cm), surface color in white light endoscopy (WLE) (whitish, normochromic or reddish), macroscopic appearance (flat or elevated, depressed), and reddish change in AIM-CE were selected as valuables. RESULTS: En bloc resection was achieved in all 54 cases, with curative resection of fifty two lesions (96.3%). Twenty three lesions (42.6%) were diagnosed as well-differentiated adenocarcinoma and the remaining 31 lesions (57.4%) were gastric adenoma. All adenocarcinoma lesions were well-differentiated tubular adenocarcinomas and were restricted within the mucosal layer. The sensitivity of reddish color change in AIM-CE is significantly higher than that in WLE (vs tumor size ? 2 cm, P = 0.016, vs normochromic or reddish surface color, P = 0.046, vs depressed macroscopic type, P = 0.0030). On the other hand, no significant differences were found in the specificity and accuracy. In univariate analysis, normochromic or reddish surface color in WLE (OR = 3.7, 95%CI: 1.2-12, P = 0.022) and reddish change in AIM-CE (OR = 14, 95%CI: 3.8-70, P < 0.001) were significantly related to diagnosis of early gastric cancer (EGC). In multivariate analysis, only reddish change in AIM-CE (OR = 11, 95%CI: 2.3-66, P = 0.0022) was a significant factor associated with diagnosis of EGC. CONCLUSION: AIM-CE may have potential for screening EGC in patients initially diagnosed as gastric adenoma by forceps biopsy.

Kono, Yoshiyasu; Takenaka, Ryuta; Kawahara, Yoshiro; Okada, Hiroyuki; Hori, Keisuke; Kawano, Seiji; Yamasaki, Yasushi; Takemoto, Koji; Miyake, Takayoshi; Fujiki, Shigeatsu; Yamamoto, Kazuhide

2014-01-01

108

Iontophoretic enhancement of leuprolide acetate by fatty acids, limonene, and depilatory lotions through porcine epidermis.  

PubMed

The effect of chemical enhancers (e.g., fatty acids, limonene, depilatory lotions) and iontophoresis was investigated on the in vitro permeability of leuprolide acetate through porcine epidermis. Franz diffusion cells and Scepter iontophoretic power source were used for the percutaneous absorption studies. Anodal iontophoresis was performed at 0.2 mA/cm2 current density. Fatty acids used were palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C18:1), linoleic (C18:2), and linolenic (C18:3) acids. The passive and iontophoretic flux were significantly (p < 0.05) greater through fatty acids-treated porcine epidermis in comparison to the control (untreated epidermis) for leuprolide acetate. The passive and iontophoretic permeability of leuprolide acetate increased with increasing number of cis double bonds. Among the fatty acids tested, linolenic acid (C18:3) exhibited the maximum permeability of leuprolide acetate during passive (51.42 x 10(-4) cm/hr) and iontophoretic (318.98 x 10(-4) cm/hr) transport. The passive and iontophoretic flux of leuprolide acetate were significantly (p < 0.05) greater through the limonene and depilatory lotion treated epidermis in comparison to their respective control. In conclusion, iontophoresis in combination with chemical enhancers synergistically increased (p < 0.05) the in vitro permeability of leuprolide acetate through porcine epidermis. PMID:15581070

Rastogi, Sumeet K; Singh, Jagdish

2004-11-01

109

Pallidol hexa-acetate ethyl acetate monosolvate  

PubMed Central

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

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

2013-01-01

110

A laboratory study of the effect of acetic acid vapor on atmospheric copper corrosion  

SciTech Connect

A study was made of the copper corrosion rate and corrosion products originated by the action of acetic acid vapor at 100% relative humidity. Copper plates were exposed to an acetic acid contaminated atmosphere for a period of 21 days. Five acetic vapor concentration levels were used. The copper corrosion rate was in the range of 1 to 23 mg/dm{sup 2} day. The corrosion-product layers were characterized using electrochemical, X-ray powder diffraction, Fourier transform infrared spectrometry, and scanning electron microscopy techniques. Thermal and calorimetric studies were also performed. Some of the compounds identified were cuprite (Cu{sub 2}O), copper acetate hydrate [Cu(CH{sub 3}COO){sub 2}{center_dot}2H{sub 2}O], and copper hydroxide acetate [Cu{sub 4}(OH)(CH{sub 3}COO){sub 7}{center_dot}2H{sub 2}O]. This last compound was also characterized. The thickness of the patina layers was 4 to 8 nm for amorphous cuprite, 11 to 48 nm for cuprite, and 225 nm for copper acetate. The patina, in which the cementation process of different corrosion-product layers plays an important role, is formed by the reaction of acetic vapor with copper through porous cuprite paths.

Lopez-Delgado, A.; Cano, E.; Bastidas, J.M.; Lopez, F.A. [Centro Nacional de Investigaciones Metalurgicas, Madrid (Spain)

1998-12-01

111

The fraction of cells that resume growth after acetic acid addition is a strain-dependent parameter of acetic acid tolerance in Saccharomyces cerevisiae.  

PubMed

High acetic acid tolerance of Saccharomyces cerevisiae is a relevant phenotype in industrial biotechnology when using lignocellulosic hydrolysates as feedstock. A screening of 38 S. cerevisiae strains for tolerance to acetic acid revealed considerable differences, particularly with regard to the duration of the latency phase. To understand how this phenotype is quantitatively manifested, four strains exhibiting significant differences were studied in more detail. Our data show that the duration of the latency phase is primarily determined by the fraction of cells within the population that resume growth. Only this fraction contributed to the exponential growth observed after the latency phase, while all other cells persisted in a viable but non-proliferating state. A remarkable variation in the size of the fraction was observed among the tested strains differing by several orders of magnitude. In fact, only 11 out of 10(7)  cells of the industrial bioethanol production strain Ethanol Red resumed growth after exposure to 157 mM acetic acid at pH 4.5, while this fraction was 3.6 × 10(6) (out of 10(7)  cells) in the highly acetic acid tolerant isolate ATCC 96581. These strain-specific differences are genetically determined and represent a valuable starting point to identify genetic targets for future strain improvement. PMID:24645649

Swinnen, Steve; Fernández-Niño, Miguel; González-Ramos, Daniel; van Maris, Antonius J A; Nevoigt, Elke

2014-06-01

112

Synthesis and in vitro transdermal penetration enhancing activity of lactam N-acetic acid esters.  

PubMed

A homologous series of N-acetic acid esters of 2-pyrrolidinone and 2-piperidinone has been prepared and evaluated for its ability to enhance the skin content and flux of hydrocortisone 21-acetate in hairless mouse skin in vitro. Enhancement ratios (ER) were determined for flux (J), 24-hour diffusion cell receptor cell concentrations (Q24), and 24-h full-thickness mouse skin steroid content (SC) and compared to control values (no enhancer present). In addition, in an attempt to abrogate toxicity, these dermal penetration enhancers were designed to have the potential for biodegradation by dermal esterases. 2-Oxopyrrolidine-alpha acetic acid dodecyl ester (5) showed the highest enhancement ratios for J (ER 67.33) and Q24 (ER 180.66). 2-Oxopiperidine-alpha-acetic acid decyl ester (10) showed a high Q24 (ER 162.07) but a lower J (ER 12.67). 2-Oxopyrrolidine-alpha-acetic acid decyl ester (3) showed the highest enhancement ratio for SC (ER 8.7). The ER Q24 for 3, 5 and 10, as well as other lactam N-acetic acid esters in this work, were significantly higher than the ER found using Azone as enhancer. PMID:8683439

Michniak, B B; Player, M R; Sowell, J W

1996-02-01

113

A comparison of the esterification of acetic acid with methanol using heterogeneous versus homogeneous acid catalysis  

Microsoft Academic Search

To investigate the similarities and differences between heterogeneous and homogeneous catalyzed esterification, the kinetics of acetic acid esterification with methanol were investigated using a commercial Nafion\\/silica nanocomposite catalyst (SAC-13) and H2SO4, respectively. Reactions were carried out in an isothermal well-mixed batch reactor at 60?°C. Organic base titration, TGA, and elemental sulfur analysis were carried out to estimate the acid site

Yijun Liu; Edgar Lotero; James G. Goodwin

2006-01-01

114

Combined sorption\\/transport of sodium dodecyl sulfate and hydrochloric acid in a blend of cellulose acetate butyrate with cellulose acetate hydrogen phthalate  

Microsoft Academic Search

The transport of hydrochloric acid (0.001–0.1 M) and sodium dodecyl sulfate (0.001–0.1 M) has been measured through a membrane consisting of a blend of cellulose acetate butyrate and cellulose acetate hydrogen phthalate. The cellulose derivative blend is suggested to suffer an alteration in the degree of hydrophobicity when in equilibrium with sodium dodecyl sulfate (SDS) through hemimicelle formation. An increase

Artur J. M. Valente; Hugh D. Burrows; Alexandre Ya. Polishchuk; Maria G. Miguel; Victor M. M. Lobo

2004-01-01

115

Performance of dairy cows fed high levels of acetic acid or ethanol.  

PubMed

Ethanol and acetic acid are common end products from silages. The main objective of this study was to determine whether high concentrations of ethanol or acetic acid in total mixed ration would affect performance in dairy cows. Thirty mid-lactation Holstein cows were grouped in 10 blocks and fed one of the following diets for 7 wk: (1) control (33% Bermuda hay + 67% concentrates), (2) ethanol [control diet + 5% ethanol, dry matter (DM) basis], or (3) acetic acid (control diet + 5% acetic acid, DM basis). Ethanol and acetic acid were diluted in water (1:2) and sprayed onto total mixed rations twice daily before feeding. An equal amount of water was mixed with the control ration. To adapt animals to these treatments, cows were fed only half of the treatment dose during the first week of study. Cows fed ethanol yielded more milk (37.9 kg/d) than those fed the control (35.8 kg/d) or acetic acid (35.3 kg/d) diets, mainly due to the higher DM intake (DMI; 23.7, 22.2, and 21.6 kg/d, respectively). The significant diet × week interaction for DMI, mainly during wk 2 and 3 (when acetic acid reached the full dose), was related to the decrease in DMI observed for the acetic acid treatment. There was a diet × week interaction in excretion of milk energy per DMI during wk 2 and 3, due to cows fed acetic acid sustained milk yield despite lower DMI. Energy efficiency was similar across diets. Blood metabolites (glucose, insulin, nonesterified fatty acids, ethanol, and ?-glutamyl transferase activity) and sensory characteristics of milk were not affected by these treatments. Animal performance suggested similar energy value for the diet containing ethanol compared with other diets. Rumen conversion of ethanol to acetate and a concomitant increase in methane production might be a plausible explanation for the deviation of the predicted energy value based on the heat of combustion. Therefore, the loss of volatile compounds during the drying process in the laboratory should be considered when calculating energy content of fermented feedstuffs. PMID:23141834

Daniel, J L P; Amaral, R C; Sá Neto, A; Cabezas-Garcia, E H; Bispo, A W; Zopollatto, M; Cardoso, T L; Spoto, M H F; Santos, F A P; Nussio, L G

2013-01-01

116

IR plus vacuum ultraviolet spectroscopy of neutral and ionic organic acid molecules and clusters: acetic acid.  

PubMed

Infrared (IR) vibrational spectroscopy of acetic acid (A) neutral and ionic monomers and clusters, employing vacuum ultraviolet (VUV), 10.5 eV single photon ionization of supersonically expanded and cooled acetic acid samples, is presented and discussed. Molecular and cluster species are identified by time of flight mass spectroscopy: the major mass features observed are A(n)H(+) (n=1-9), ACOOH(+) (VUV ionization) without IR radiation present, and A(+) with both IR and VUV radiation present. The intense feature ACOOH(+) arises from the cleavage of (A)(2) at the beta-CC bond to generate ACOOH(+)+CH(3) following ionization. The vibrational spectrum of monomeric acetic acid (2500-7500 cm(-1)) is measured by nonresonant ionization detected infrared (NRID-IR) spectroscopy. The fundamentals and overtones of the CH and OH stretches and some combination bands are identified in the spectrum. Mass selected IR spectra of neutral and cationic acetic acid clusters are measured in the 2500-3800 cm(-1) range employing nonresonant ionization dip-IR and IR photodissociation (IRPD) spectroscopies, respectively. Characteristic bands observed at approximately 2500-2900 cm(-1) for the cyclic ring dimer are identified and tentatively assigned. For large neutral acetic acid clusters A(n)(n>2), spectra display only hydrogen bonded OH stretch features, while the CH modes (2500-2900 cm(-1)) do not change with cluster size n. The IRPD spectra of protonated (cationic) acetic acid clusters A(n)H(+) (n=1-7) exhibit a blueshift of the free OH stretch with increasing n. These bands finally disappear for n> or =6, and one broad and weak band due to hydrogen bonded OH stretch vibrations at approximately 3350 cm(-1) is detected. These results indicate that at least one OH group is not involved in the hydrogen bonding network for the smaller (n< or =5) A(n)H(+) species. The disappearance of the free OH stretch feature at n> or =6 suggests that closed cyclic structures form for A(n)H(+) for the larger clusters (n> or =6). PMID:17115753

Hu, Y J; Fu, H B; Bernstein, E R

2006-11-14

117

Heterogeneous photocatalytic synthesis of methane from acetic acid: new Kolbe reaction pathway  

Microsoft Academic Search

The heterogeneous photocatalytic decomposition of acetic acid on n-type TiOâ to yield almost exclusively methane and carbon dioxide is reported. Probable reaction mechanisms are discussed. It is assumed that the TiOâ powder acts in a dual function causing the photooxidation of acetate and the reduction of intermediately formed methyl radicals. This property is not found at metal electrodes under usual

Bernhard Kraeutler; Allen J. Bard

1978-01-01

118

Radiofrequency Thermal Ablation: Increase in Lesion Diameter with Continuous Acetic Acid Infusion  

SciTech Connect

Purpose. To evaluate the influence of continuous infusion of acetic acid 50% during radiofrequency ablation (RFA) on the size of the thermal lesion produced. Methods. Radiofrequency (RF) was applied to excised bovine liver by using an expandable needle electrode with 10 retractable tines (LeVeen Needle Electrode, RadioTherapeutics, Sunnyvale, CA) connected to a commercially available RF generator (RF 2000, RadioTherapeutics, Sunnyvale, CA). Experiments were performed using three different treatment modalities: RF only (n = 15), RF with continuous saline 0.9% infusion (n = 15), and RF with continuous acetic acid 50% infusion (n = 15). RF duration, power output, tissue impedance, and time to a rapid rise in impedance were recorded. The ablated lesions were evaluated both macroscopically and histologically. Results. The ablated lesions appeared as spherical or ellipsoid, well-demarcated pale areas with a surrounding brown rim with both RF only and RF plus saline 0.9% infusion. In contrast, thermolesions generated with RF in combination with acetic acid 50% infusion were irregular in shape and the central portion was jelly-like. Mean diameter of the coagulation necrosis was 22.3 {+-} 2.1 mm (RF only), 29.2 {+-} 4.8 mm (RF + saline 0.9%) and 30.7 {+-} 5.7 mm (RF + acetic acid 50%), with a significant increase in the RF plus saline 0.9% and RF plus acetic acid 50% groups compared with RF alone. Time to a rapid rise in impedance was significantly prolonged in the RF plus saline 0.9% and RF plus acetic acid 50% groups compared with RF alone. Conclusions. A combination of RF plus acetic acid 50% infusion is able to generate larger thermolesions than RF only or RF combined with saline 0.9% infusion.

Lubienski, Andreas [Ruprecht-Karls-University Heidelberg, Department of Diagnostic Radiology (Germany)], E-mail: lubienski@radiologie.uni-luebeck.de; Duex, Markus [Hospital Northwest Frankfurt, Department of Radiology (Germany); Lubienski, Katrin; Grenacher, Lars; Kauffmann, Guenter [Ruprecht-Karls-University Heidelberg, Department of Diagnostic Radiology (Germany)

2005-12-15

119

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

120

Adsorptive Membranes vs. Resins for Acetic Acid Removal from Biomass Hydrolysates  

SciTech Connect

Acetic acid is a compound commonly found in hemicellulosic hydrolysates. This weak acid strongly influences the bioconversion of sugar containing hydrolysates. Previous investigators have used anion exchange resins for acetic acid removal from different hemicellulosic hydrolysates. In this study, the efficiency of an anion exchange membrane was compared to that of an anion exchange resin, for acetic acid removal from a DI water solution and an acidic hemicellulose hydrolysate pretreated using two different methods. Ion exchange membranes and resins have very different geometries. Here the performance of membranes and resins is compared using two dimensionless parameters, the relative mass throughput and chromatographic bed number. The relative mass throughput arises naturally from the Thomas solution for ion exchange. The results show that the membrane exhibit better performance in terms of capacity, and loss of the desired sugars. In addition acetic acid may be eluted at a higher concentration from the membrane thus leading to the possibility of recovery and re-use of the acetic acid.

Han, B.; Carvalho, W.; Canilha, L.; da Silva, S. S.; e Silva, J. B. A.; McMillan, J. D.; Wickramasinghe, S. R.

2006-01-01

121

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

PubMed

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

Pérez-Díaz, I M; McFeeters, R F

2008-08-01

122

A case report of a chemical burn due to the misuse of glacial acetic acid.  

PubMed

As young and elastic skin is what everyone dreams of, various measures have been implemented including chemical, laser resurfacing and dermabrasion to improve the condition of ageing skin. However, the high cost of these procedures prevents the poor from having access to treatment. Glacial acetic acid is widely used as a substitute for chemical peeling because it is readily easily available and affordable. However, its use can result in a number of serious complications. A 28-year-old female patient was admitted to our hospital with deep second-degree chemical burns on her face caused by the application of a mixture of glacial acetic acid and flour for chemical peeling. During a 6-month follow-up, hypertrophic scarring developed on the both nasolabial folds despite scar management. Glacial acetic acid is a concentrated form of the organic acid, which gives vinegar its sour taste and pungent smell, and it is also an important reagent during the production of organic compounds. Unfortunately, misleading information regarding the use of glacial acetic acid for chemical peeling is causing serious chemical burns. Furthermore, there is high possibility of a poor prognosis, which includes inflammation, hypertrophic scar formation and pigmentation associated with its misuse. Therefore, we report a case of facial chemical burning, due to the misuse of glacial acetic acid, and hope that this report leads to a better understanding regarding the use of this reagent. PMID:20708991

Yoo, Jun-Ho; Roh, Si-Gyun; Lee, Nae-Ho; Yang, Kyung-Moo; Moon, Ji-Hyun

2010-12-01

123

Coproduction of acetic acid and electricity by application of microbial fuel cell technology to vinegar fermentation.  

PubMed

The coproduction of a useful material and electricity via a novel application of microbial fuel cell (MFC) technology to oxidative fermentation was investigated. We focused on vinegar production, i.e., acetic acid fermentation, as an initial and model useful material that can be produced by oxidative fermentation in combination with MFC technology. The coproduction of acetic acid and electricity by applying MFC technology was successfully demonstrated by the simultaneous progress of acetic acid fermentation and electricity generation through a series of repeated batch fermentations. Although the production rate of acetic acid was very small, it increased with the number of repeated batch fermentations that were conducted. We obtained nearly identical (73.1%) or larger (89.9%) acetic acid yields than that typically achieved by aerated fermentation (75.8%). The open-cycle voltages measured before and after fermentation increased with the total fermentation time and reached a maximum value of 0.521 V prior to the third batch fermentation. The maximum current and power densities measured in this study (19.1 ?A/cm² and 2.47 ?W/cm², respectively) were obtained after the second batch fermentation. PMID:23518569

Tanino, Takanori; Nara, Youhei; Tsujiguchi, Takuya; Ohshima, Takayuki

2013-08-01

124

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

PubMed Central

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

Macias, Miguel Macias; Manso, Antonio Garcia; Orellana, Carlos Javier Garcia; Velasco, Horacio Manuel Gonzalez; Caballero, Ramon Gallardo; Chamizo, Juan Carlos Peguero

2013-01-01

125

Asaia bogorensis gen. nov., sp. nov., an unusual acetic acid bacterium in the alpha-Proteobacteria.  

PubMed

Eight Gram-negative, aerobic, rod-shaped and peritrichously flagellated strains were isolated from flowers of the orchid tree (Bauhinia purpurea) and of plumbago (Plumbago auriculata), and from fermented glutinous rice, all collected in Indonesia. The enrichment culture approach for acetic acid bacteria was employed, involving use of sorbitol medium at pH 3.5. All isolates grew well at pH 3.0 and 30 degrees C. They did not oxidize ethanol to acetic acid except for one strain that oxidized ethanol weakly, and 0.35% acetic acid inhibited their growth completely. However, they oxidized acetate and lactate to carbon dioxide and water. The isolates grew well on mannitol agar and on glutamate agar, and assimilated ammonium sulfate for growth on vitamin-free glucose medium. The isolates produced acid from D-glucose, D-fructose, L-sorbose, dulcitol and glycerol. The quinone system was Q-10. DNA base composition ranged from 59.3 to 61.0 mol% G + C. Studies of DNA relatedness showed that the isolates constitute a single species. Phylogenetic analysis based on their 16S rRNA gene sequences indicated that the isolates are located in the acetic acid bacteria lineage, but distant from the genera Acetobacter, Gluconobacter, Acidomonas and Gluconacetobacter. On the basis of the above characteristics, the name Asaia bogorensis gen. nov., sp. nov. is proposed for these isolates. The type strain is isolate 71T (= NRIC 0311T = JCM 10569T). PMID:10758893

Yamada, Y; Katsura, K; Kawasaki, H; Widyastuti, Y; Saono, S; Seki, T; Uchimura, T; Komagata, K

2000-03-01

126

Determination of formic-acid and acetic acid concentrations formed during hydrothermal treatment of birch wood and its relation to colour, strength and hardness  

Microsoft Academic Search

Formation of benzyl esters from acetic and formic acids during heat treatment of birch at 160–200°C has been studied by gas chromatography. High concentrations of formic and acetic acids formed by the wood itself during hydrothermal treatment were found. The concentrations of acids increased with both treatment time and temperature. The maximum formic- and acetic acid concentrations found at 180°C

Bror Sundqvist; Olov Karlsson; Ulla Westermark

2006-01-01

127

Large prebiotic molecules in space: photophysics of acetic acid and its isomers  

NASA Astrophysics Data System (ADS)

An increasing number of large molecules have been positively identified in space. Many of these molecules are of biological interest and thus provide insight into prebiotic organic chemistry in the protoplanetary nebula. Among these molecules, acetic acid is of particular importance due to its structural proximity to glycine, the simplest amino acid. We compute electronic and vibrational properties of acetic acid and its isomers, methyl formate and glycolaldehyde, using density functional theory. From the computed photoabsorption cross-sections, we obtain the corresponding photoabsorption rates for solar radiation at 1au and find them in good agreement with previous estimates. We also discuss glycolaldehyde diffuse emission in Sgr B2(N), as opposite to emissions from methyl formate and acetic acid that appear to be concentrated in the compact region Sgr B2(N-LMH).

Puletti, Fabrizio; Malloci, Giuliano; Mulas, Giacomo; Cecchi-Pestellini, Cesare

2010-03-01

128

Ethenzamide-gentisic acid-acetic acid (2/1/1)  

PubMed Central

In the title co-crystal solvate, 2-ethoxy­benzamide–2,5-dihydroxy­benzoic acid–ethanoic acid (2/1/1), 2C9H11NO2·C7H6O4·C2H4O2, two nonsteroidal anti-inflammatory drugs, ethenzamide (systematic name: 2-ethoxy­benzamide) and gentisic acid (systematic name: 2,5-dihydroxy­benzoic acid), together with acetic acid (systematic name: ethanoic acid) form a four-component mol­ecular assembly held together by N—H?O and O—H?O hydrogen bonds. This assembly features two symmetry-independent mol­ecules of ethenzamide, forming supra­molecular acid–amide heterosynthons with gentisic acid and acetic acid. These heterosynthons involve quite strong O—H?O [O?O = 2.5446?(15) and 2.5327?(15)?Å] and less strong N—H?O [N?O = 2.9550?(17) and 2.9542?(17)?Å] hydrogen bonds. The overall crystal packing features several C—H?O and ?–? stacking inter­actions [centroid–centroid distance = 3.7792?(11)?Å].

Aitipamula, Srinivasulu; Chow, Pui Shan; Tan, Reginald B.H.

2010-01-01

129

Purification and Partial Characterization of a Glucan Containing Indole-3-acetic Acid 1  

PubMed Central

The “bound auxin” of Zea mays, first described by Berger and Avery (Amer. J. Bot. 1944; 31: 199-203) has been purified and partially characterized. It is an indole-3-acetic acid-containing, high molecular weight, lipophilic cellulosicglucan. The indole-3-acetic acid is in ester linkage as evidenced by indoleacetamide formation upon ammonolysis. The glucan is of variable chain length and comprises, in general, 35 to 50 per cent of the dry weight of the compound. The glucosidic residues are ? 1 ? 4 linked and are hydrolyzed by cellulase. Mild acid hydrolysis produces cellobiose and cellotriose. Other components, as yet unidentified, of the compound are described.

Piskornik, Zdzislaw; Bandurski, Robert S.

1972-01-01

130

Conductometric simultaneous determination of acetic acid, monochloroacetic acid and trichloroacetic acid using orthogonal signal correction-partial least squares  

Microsoft Academic Search

A simultaneous conductometric titration method for determination of mixtures of acetic acid, monochloroacetic acid and trichloroacetic acid based on the multivariate calibration partial least squares is proposed. It is possible to obtain an adjustable model to relate squared concentration values of the mixtures used in the calibration range by conductance. The effect of orthogonal signal correction (OSC) as a preprocessing

R. Ghorbani; J. Ghasemi; B. Abdollahi

2006-01-01

131

Hydrogen production by catalytic steam reforming of acetic acid, a model compound of biomass pyrolysis liquids  

Microsoft Academic Search

An environmentally friendly and cost-competitive way of producing hydrogen is the catalytic steam reforming of biomass pyrolysis liquids, known as bio-oil, which can be separated into two fractions: ligninic and aqueous. Acetic acid has been identified as one of the major organic acids present in the latter, and catalytic steam reforming has been studied for this model compound. Three different

F. Bimbela; M. Oliva; J. Ruiz; L. García; J. Arauzo

2007-01-01

132

Volatile acetic acid and formaldehyde emission from plywood treated with boron compound  

Microsoft Academic Search

The effects of plywood on formaldehyde and volatile acetic acid emissions treated with borax and boric acid were investigated. The treated plywood samples were manufactured by using two different methods; each veneer was first impregnated by a dipping method before the first group of plywood was manufactured. The second group of plywood panels was produced by adding preservatives (borax, boric

S. Colak; G. Colakoglu

2004-01-01

133

Extraction equilibria of acetic and propionic acids from dilute aqueous solution by several solvents  

SciTech Connect

Extraction equilibria of acetic acid and propionic acid with hexane solutions of trioctyl amine, trioctyl phosphine oxide, and tributyl phosphate were studied. The species formed in the systems were estimated, and the distribution coefficients and the equilibrium constants for these species were evaluated.s

Fahim, M.A. (Univ. of United Arab Emirates, Al-Ain (United Arab Emirates))

1992-10-01

134

Determination of Monochloroacetic Acid and Dichloroacetic Acid for Quality Control of Acetic Acid Chlorination Industry by Ion Chromatography  

Microsoft Academic Search

An ion chromatographic method is described for the purpose of quality control in the process of monochloroacetic acid production. Using 2.5 mM NaOH–10% methanol as eluent, the simultaneous determination of acetic acid, monochloroacetic acid, dichloroacetic acid, and Cl? was obtained in a single run. Monochloroacetic acid and dichloroacetic acid showed good linearity in the range 0.1–20 and 0.15–20 ?g\\/ml and

Feng Qu; Shifen Mou

1999-01-01

135

An Explanation of the Inhibition of Root Growth Caused by Indole-3-Acetic Acid 1  

PubMed Central

Low concentrations of indole-3-acetic acid inhibit the growth of pea root sections by inducing the formation of the growth regulator, ethylene gas. Ethylene is produced within 15 to 30 minutes after indole-3-acetic acid is applied and roots begin to swell immediately after they are exposed to the gas. Carbon dioxide competitively inhibits ethylene action in roots, impedes their geotropic response, and partially reinstates auxin inhibited growth. It is concluded that ethylene participates in the geotropic response of roots, but not that of stems. Images

Chadwick, Arthur V.; Burg, Stanley P.

1967-01-01

136

Acetic acid bacteria and the production and quality of wine vinegar.  

PubMed

The production of vinegar depends on an oxidation process that is mainly performed by acetic acid bacteria. Despite the different methods of vinegar production (more or less designated as either "fast" or "traditional"), the use of pure starter cultures remains far from being a reality. Uncontrolled mixed cultures are normally used, but this review proposes the use of controlled mixed cultures. The acetic acid bacteria species determine the quality of vinegar, although the final quality is a combined result of technological process, wood contact, and aging. This discussion centers on wine vinegar and evaluates the effects of these different processes on its chemical and sensory properties. PMID:24574887

Mas, Albert; Torija, María Jesús; García-Parrilla, María del Carmen; Troncoso, Ana María

2014-01-01

137

Metal-organic frameworks of vanadium as catalysts for conversion of methane to acetic acid.  

PubMed

A catalytic system combining the high activity of homogeneous catalysts and the ease of use of heterogeneous catalysts for methane activation is reported. The vanadium-containing metal-organic frameworks (MOFs) MIL-47 and MOF-48 are found to have high catalytic activity and chemical stability. They convert methane selectively to acetic acid with 70% yield (490 TON) based on K(2)S(2)O(8) as an oxidant. Isotopic labeling experiments showed that two methane molecules are converted to the produced acetic acid. The MOF catalysts are reusable and remain catalytically active for several recycling steps without losing their crystalline structures. PMID:21766786

Phan, Anh; Czaja, Alexander U; Gándara, Felipe; Knobler, Carolyn B; Yaghi, Omar M

2011-08-15

138

21 CFR 184.1185 - Calcium acetate.  

Code of Federal Regulations, 2011 CFR

, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981),...

2013-04-01

139

21 CFR 184.1185 - Calcium acetate.  

Code of Federal Regulations, 2010 CFR

, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981),...

2012-04-01

140

Nanofabrication in cellulose acetate.  

PubMed

We have demonstrated nanofabrication with commercialized cellulose acetate. Cellulose acetate is used for bulk nanofabrication and surface nanofabrication. In bulk nanofabrication, cellulose acetate reacts with an e-beam and permanent patterns are formed in it instead of being transferred to other substrates. We have studied the nano relief modulation performance of cellulose acetate before and after development. The depth of the nanopatterns is magnified after development, and is varied by exposing dosage and line width of the pattern. The thinnest 65 nm wide line is achieved in the bulk fabrication. We also demonstrate a binary phase Fresnel lens array which is directly patterned in a cellulose acetate sheet. Because of its unique mechanical and optical properties, cellulose is a good candidate for a template material for soft imprinting lithography. In the surface nanofabrication, cellulose acetate thin film spin-coated on silicon wafers is employed as a new resist for e-beam lithography. We achieved 50 nm lines with 100 nm pitches, dots 50 nm in diameter, and single lines with the smallest width of 20 nm. As a new resist of e-beam lithography, cellulose acetate has high resolution comparable with conventional resists, while having several advantages such as low cost, long stock time and less harmfulness to human health. PMID:19224020

Zeng, Hongjun; Lajos, Robert; Metlushko, Vitali; Elzy, Ed; An, Se Young; Sautner, Joshua

2009-03-01

141

Carbon-isotopic analysis of dissolved acetate  

Microsoft Academic Search

Heating of dried, acetate-containing solids together with oxalic acid dihydrate conveniently releases acetic acid for purification by gas chromatography. For determination of the carbon-isotopic composition of total acetate, the acetate-containing zone of the chromatographic effluent can be routed directly to a combustion furnace coupled to a vacuum system allowing recovery, purification, and packaging of COâ for mass-spectrometric analysis. For analysis

Jeffrey T. Gelwicks; J. M. Hayes

1990-01-01

142

Use of acetic and citric acids to control Salmonella Typhimurium in tahini (sesame paste).  

PubMed

Since tahini and its products have been linked to Salmonella illness outbreaks and product recalls in recent years, this study assessed the ability of Salmonella Typhimurium to survive or grow in commercial tahini and when hydrated (10% w/v in water), treated with 0.1%-0.5% acetic or citric acids, and stored at 37, 21 and 10 °C for 28 d. S. Typhimurium survived in commercial tahini up to 28 d but was reduced in numbers from 1.7 to 3.3 log10 CFU/ml. However, in the moist or hydrated tahini, significant growth of S. Typhimurium occurred at the tested temperatures. Acetic and citric acids at ?0.5% reduced S. Typhimurium by 2.7-4.8 log10 CFU/ml and 2.5-3.8 log10 CFU/ml, respectively, in commercial tahini at 28 d. In hydrated tahini the organic acids were more effective. S. Typhimurium cells were not detected in the presence of 0.5% acetic acid after 7 d or with 0.5% citric acid after 21 d at the tested temperatures. The ability of S. Typhimurium to grow or survive in commercial tahini and products containing hydrated tahini may contribute to salmonellosis outbreaks; however, use of acetic and citric acids in ready-to-eat foods prepared from tahini can significantly minimize the risk associated with this pathogen. PMID:24929724

Al-Nabulsi, Anas A; Olaimat, Amin N; Osaili, Tareq M; Shaker, Reyad R; Zein Elabedeen, Noor; Jaradat, Ziad W; Abushelaibi, Aisha; Holley, Richard A

2014-09-01

143

Inhibition of microbial xylitol production by acetic acid and its relation with fermentative parameters.  

PubMed

Precipitated sugarcane bagasse hemicellulosic hydrolysate containing acetic acid was fermented by Candida guilliermondii FTI20037 under different operational conditions (pH 4.0 and 7.0, three aeration rates). At pH 7.0 and kLa of 10 (0.75 vvm) and 22.5/h (3.0 vvm) the acetic acid had not been consumed until the end of the fermentations, whereas at the same pH and kLa of 35/h (4.5 vvm) the acid was rapidly consumed and acetic acid inhibition was not important. On the other hand, fermentations at an initial pH of 4.0 and kLa of 22.5 and 35/h required less time for the acid uptake than fermentations at kLa of 10/h. The acetic acid assimilation by the yeast indicates the ability of this strain to ferment in partially detoxified medium, making possible the utilization of the sugarcane bagasse hydrolysate in this bio-process. The effects on xylitol yield and production are reported. PMID:10849838

Morita, T A; Silva, S S

2000-01-01

144

Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid and methylglyoxal  

NASA Astrophysics Data System (ADS)

Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including pyruvate, oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA). Acetic acid plays a central role in the aqueous oxidation of methylglyoxal and it is a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid (20 ?M-10 mM) was oxidized by OH radicals, and pyruvic acid and methylglyoxal experimental samples were analyzed using new analytical methods, in order to better understand the formation of SOA from acetic acid and methylglyoxal. Glyoxylic, glycolic, and oxalic acids formed from acetic acid and OH radicals. In contrast to the aqueous OH radical oxidation of methylglyoxal, the aqueous OH radical oxidation of acetic acid did not produce succinic acid and oligomers. This suggests that the methylgloxal-derived oligomers do not form through the acid catalyzed esterification pathway proposed previously. Using results from these experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

Tan, Y.; Lim, Y. B.; Altieri, K. E.; Seitzinger, S. P.; Turpin, B. J.

2012-01-01

145

Carbon-isotopic analysis of dissolved acetate  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

146

Lipidomic profiling of Saccharomyces cerevisiae and Zygosaccharomyces bailii reveals critical changes in lipid composition in response to acetic acid stress.  

PubMed

When using microorganisms as cell factories in the production of bio-based fuels or chemicals from lignocellulosic hydrolysate, inhibitory concentrations of acetic acid, released from the biomass, reduce the production rate. The undissociated form of acetic acid enters the cell by passive diffusion across the lipid bilayer, mediating toxic effects inside the cell. In order to elucidate a possible link between lipid composition and acetic acid stress, the present study presents detailed lipidomic profiling of the major lipid species found in the plasma membrane, including glycerophospholipids, sphingolipids and sterols, in Saccharomyces cerevisiae (CEN.PK 113_7D) and Zygosaccharomyces bailii (CBS7555) cultured with acetic acid. Detailed physiological characterization of the response of the two yeasts to acetic acid has also been performed in aerobic batch cultivations using bioreactors. Physiological characterization revealed, as expected, that Z. bailii is more tolerant to acetic acid than S. cerevisiae. Z. bailii grew at acetic acid concentrations above 24 g L(-1), while limited growth of S. cerevisiae was observed after 11 h when cultured with only 12 g L(-1) acetic acid. Detailed lipidomic profiling using electrospray ionization, multiple-reaction-monitoring mass spectrometry (ESI-MRM-MS) showed remarkable changes in the glycerophospholipid composition of Z. bailii, including an increase in saturated glycerophospholipids and considerable increases in complex sphingolipids in both S. cerevisiae (IPC 6.2×, MIPC 9.1×, M(IP)2C 2.2×) and Z. bailii (IPC 4.9×, MIPC 2.7×, M(IP)2C 2.7×), when cultured with acetic acid. In addition, the basal level of complex sphingolipids was significantly higher in Z. bailii than in S. cerevisiae, further emphasizing the proposed link between lipid saturation, high sphingolipid levels and acetic acid tolerance. The results also suggest that acetic acid tolerance is associated with the ability of a given strain to generate large rearrangements in its lipid profile. PMID:24023914

Lindberg, Lina; Santos, Aline Xs; Riezman, Howard; Olsson, Lisbeth; Bettiga, Maurizio

2013-01-01

147

Pervaporation characteristics of polyetherimide\\/?-alumina composite membrane for a quaternary equilibrium mixture of acetic acid-ethanol-ethyl acetate-water  

Microsoft Academic Search

Polyetherimide\\/?-alumina composite membrane has been prepared by dipping method for further reactor application. Separation\\u000a factors and permeances for a quaternary acetic acid-ethanol-ethyl acetate-water equilibrium feed mixture have been measured\\u000a on the composite membrane in the range of temperature from 303 K up to 343 K and space time from 27 sec to 27,000 sec at a\\u000a permeate-side pressure of 2.67?10-3

Byoung-Gi Park

2004-01-01

148

Formic and acetic acid over the central Amazon region, Brazil 1. Dry season  

SciTech Connect

We have determined the atmospheric concentrations of formic and acetic acid in the gas phase, in aerosols, and in rain during the dry season (July--August 1985) in the Amazonia region of Brazil. At ground level the average concentrations of gas phase formic and acetic acid were 1.6 +- 0.6 and 2.2 +- 1.0 ppb, respectively. The diurnal behavior of both acids at ground level and their vertical distribution in the forest canopy point to the existence of vegetative sources as well as to production by chemical reactions in the atmosphere. Dry deposition of the gaseous acids appears to be a major sink. The concentrations of formic and acetic acid in the gas phase were about 2 orders of magnitude higher than concentrations of the corresponding species in the atmospheric aerosol. About 50--60%/sub 0/ of the aerosol (total) formate and acetate were in the size fraction below 1.0 ..mu..m diameter.

Andreae, M.O.; Talbot, R.W.; Andreae, T.W.; Harriss, R.C.

1988-02-20

149

Theophylline-7-acetic acid derivatives with amino acids as anti-tuberculosis agents.  

PubMed

A series of amides were synthesized by condensation of theophylline-7-acetic acid and eight commercially available amino acid methyl ester hydrochlorides. Consecutive hydrolysis of six of the amido-esters resulted in the formation of corresponding amido-acids. The newly synthesized compounds were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv. The activity varied depending on the amino acid fragments and in seven cases exerted excellent values with MICs 0.46-0.26?M. Assessment of the cytotoxicity revealed that the compounds were not cytotoxic against the human embryonal kidney cell line HEK-293T. The theophylline-7-acetamides containing amino acid moieties appear to be promising lead compounds for the development of antimycobacterial agents. PMID:24878196

Voynikov, Yulian; Valcheva, Violeta; Momekov, Georgi; Peikov, Plamen; Stavrakov, Georgi

2014-07-15

150

Acetic Acid, the Active Component of Vinegar, Is an Effective Tuberculocidal Disinfectant  

PubMed Central

ABSTRACT Effective and economical mycobactericidal disinfectants are needed to kill both Mycobacterium tuberculosis and non-M. tuberculosis mycobacteria. We found that acetic acid (vinegar) efficiently kills M. tuberculosis after 30 min of exposure to a 6% acetic acid solution. The activity is not due to pH alone, and propionic acid also appears to be bactericidal. M. bolletii and M. massiliense nontuberculous mycobacteria were more resistant, although a 30-min exposure to 10% acetic acid resulted in at least a 6-log10 reduction of viable bacteria. Acetic acid (vinegar) is an effective mycobactericidal disinfectant that should also be active against most other bacteria. These findings are consistent with and extend the results of studies performed in the early and mid-20th century on the disinfectant capacity of organic acids. IMPORTANCE  Mycobacteria are best known for causing tuberculosis and leprosy, but infections with nontuberculous mycobacteria are an increasing problem after surgical or cosmetic procedures or in the lungs of cystic fibrosis and immunosuppressed patients. Killing mycobacteria is important because Mycobacterium tuberculosis strains can be multidrug resistant and therefore potentially fatal biohazards, and environmental mycobacteria must be thoroughly eliminated from surgical implements and respiratory equipment. Currently used mycobactericidal disinfectants can be toxic, unstable, and expensive. We fortuitously found that acetic acid kills mycobacteria and then showed that it is an effective mycobactericidal agent, even against the very resistant, clinically important Mycobacterium abscessus complex. Vinegar has been used for thousands of years as a common disinfectant, and if it can kill mycobacteria, the most disinfectant-resistant bacteria, it may prove to be a broadly effective, economical biocide with potential usefulness in health care settings and laboratories, especially in resource-poor countries.

Cortesia, Claudia; Vilcheze, Catherine; Bernut, Audrey; Contreras, Whendy; Gomez, Keyla; de Waard, Jacobus; Jacobs, William R.; Kremer, Laurent; Takiff, Howard

2014-01-01

151

Cellulose esterification with fatty acids and acetic anhydride in lithium chloride\\/ N,N -dimethylacetamide medium  

Microsoft Academic Search

Homogeneous esterification of cellulose with saturated fatty acids (n-octanoic to n-octadecanoic) was accomplished with acetic anhydride co-reactant in lithium chloride\\/N,N-dimethylacetamide (LiCl\\/DMAc) medium. Cellulose mixed triesters (CMT) were obtained after 5 h at 130°C with an average of\\u000a 2.2 acetyl groups and 0.8 fatty substituents per anhydroglucose unit. A mixed acetic-fatty anhydride, formed in situ, accounts for the grafting of the

C. Vaca-Garcia; S. Thiebaud; M. E. Borredon; G. Gozzelino

1998-01-01

152

Enhanced biofuel production through coupled acetic acid and xylose consumption by engineered yeast.  

PubMed

The anticipation for substituting conventional fossil fuels with cellulosic biofuels is growing in the face of increasing demand for energy and rising concerns of greenhouse gas emissions. However, commercial production of cellulosic biofuel has been hampered by inefficient fermentation of xylose and the toxicity of acetic acid, which constitute substantial portions of cellulosic biomass. Here we use a redox balancing strategy to enable efficient xylose fermentation and simultaneous in situ detoxification of cellulosic feedstocks. By combining a nicotinamide adenine dinucleotide (NADH)-consuming acetate consumption pathway and an NADH-producing xylose utilization pathway, engineered yeast converts cellulosic sugars and toxic levels of acetate together into ethanol under anaerobic conditions. The results demonstrate a breakthrough in making efficient use of carbon compounds in cellulosic biomass and present an innovative strategy for metabolic engineering whereby an undesirable redox state can be exploited to drive desirable metabolic reactions, even improving productivity and yield. PMID:24105024

Wei, Na; Quarterman, Josh; Kim, Soo Rin; Cate, Jamie H D; Jin, Yong-Su

2013-01-01

153

Amonia gas: an improved reagent for chemical ionization mass spectrometry of bile acid methyl ester acetates  

Microsoft Academic Search

The ammonia chemical ionization mass spectra of 28 methyl ester acetate derivatives of bile acids and related compounds have been determined by gas-liquid chromatography-mass spectrometry. Advantages of ammonia ionization over the previously studied isobutane ionization include a 130 to 270% enhancement in the sensitivity of base peak monitoring, and direct determination of molecular weight from the base peak (M +

B. R. DeMark; P. D. Klein

1981-01-01

154

Indole3-acetic acid increases glutamine utilization by high peroxidase activity-presenting leukocytes  

Microsoft Academic Search

Indole-3-acetic acid (IAA) is toxic for human tumor cells and in association with horseradish peroxidase (HRP) can be used as a new prodrug\\/enzyme combination for targeted cancer therapy. The toxic effect of IAA on neutrophils, macrophages and lymphocytes is associated with cell peroxidase activity, which is high in neutrophils and low in lymphocytes. The effect of IAA on glucose and

Mariza P De Melo; Tania C Pithon-Curi; Rui Curi

2004-01-01

155

Seasonal Allergic Rhinitic and Normal Subjects Respond Differentially to Nasal Provocation with Acetic Acid Vapor  

Microsoft Academic Search

Individuals with seasonal allergic rhinitis (SAR) show a more marked nasal obstructive response (increases in nasal airways resistance or NAR) after provocation with chlorine gas (Cl2) than do nonrhinitic (NR) controls. We were interested in learning whether similar differential respon- siveness was apparent after provocation with acetic acid vapor. Sixteen nonsmoking, nonasth- matic subjects, aged 21-63 yr, equally divided by

Dennis shusterman; Alice Tarun; Mary Alice Murphy; John Morris

2005-01-01

156

New N- and O-arylations with phenylboronic acids and cupric acetate  

Microsoft Academic Search

A new method of arylating N?H and O?H containing compounds at room temperature with phenylboronic acids and cupric acetate in the presence of a tertiary amine promoter is described. Substrates include phenols, amines, anilines, amides, imides, ureas, carbamates, and sulfonamides.

Dominic M. T Chan; Kevin L Monaco; Ru-Ping Wang; Michael P Winters

1998-01-01

157

Kinetics of hydroxyapatite dissolution in acetic, lactic, and phosphoric acid solutions  

Microsoft Academic Search

Summary The present study was undertaken in an attempt to relate the kinetics of hydroxyapatite dissolution to solution parameters, under experimental conditions relevant to the dental caries process. Thus, the dissolution of hydroxyapatite was studied in acetic, lactic, and dilute phosphoric acid solutions having initial pH values from 4 to 6. Rates of dissolution and the corresponding degree of saturation

H. C. Margolis; E. C. Moreno

1992-01-01

158

Divergent effects of flavone acetic acid on established versus developing tumour blood flow  

Microsoft Academic Search

Flavone Acetic Acid (FAA) exerts much of its effect by reducing tumour blood flow. Previous studies on FAA-induced changes in blood flow have used established tumours with a functional microvasculature. Using radioactive Xenon(133Xe) clearance to monitor local blood flow we show that the effects of FAA are dependent on the presence of this functional microvasculature with no evidence that FAA

V Mahadevan; IR Hart

1991-01-01

159

Population dynamics of acetic acid bacteria during traditional wine vinegar production.  

PubMed

The population dynamics of acetic acid bacteria in traditional vinegar production was determined in two independent vinegar plants at both the species and strain level. The effect of barrels made of four different woods upon the population dynamics was also determined. Acetic acid bacteria were isolated on solid media and the species were identified by RFLP-PCR of 16S rRNA genes and confirmed by 16S rRNA gene sequencing, while strains were typed by ERIC-PCR and (GTG)(5)-rep-PCR. The most widely isolated species was Acetobacter pasteurianus, which accounted for 100% of all the isolates during most of the acetification. Gluconacetobacter europaeus only appeared at any notable level at the end of the process in oak barrels from one vinegar plant. The various A. pasteurianus strains showed a clear succession as the concentration of acetic acid increased. In both vinegar plants the relative dominance of different strains was modified as the concentrations of acetic acid increased, and strain diversity tended to reduce at the end of the process. PMID:20117853

Vegas, Carlos; Mateo, Estibaliz; González, Angel; Jara, Carla; Guillamón, José Manuel; Poblet, Montse; Torija, Ma Jesús; Mas, Albert

2010-03-31

160

Karplus-type relationship for quadrupole coupling constants and asymmetry parameters for substituted acetic acids  

SciTech Connect

The deuterium quadrupole coupling constant for the methyl group in acetic acid dimer was calculated as a function of the torsion angle about the carbon-carbon bond. The results show that when a deuteron approaches either of the negatively charged oxygen atoms, the quadrupole coupling constant for the deuteron is reduced by as much as 4.2 kHz. Both the calculated quadrupole coupling constant, e/sup 2/q/sub zz/Q/h, and asymmetry parameter, eta, are fitted with a Karplus-type equation: e/sup 2/q/sub zz/Q/h = A - 0.5491 cos theta - 1.7859 cos 2theta; eta = 0.0491 + 0.0058 cos theta - 0.0081 cos 2theta. Adiabatic demagnetization in the laboratory frame spectroscopy at 77 K for (4-chlorophenyl)(2,2-/sup 2/H/sub 2/)acetic acid showed two inequivalent deuteron sites that, on the basis of deuterium double transitions, are demonstrated to be due to two deuterium sites bound to the same carbon atom. The solid-state structure of (4-chlorophenyl)acetic acid was determined by single-crystal X-ray diffraction. The ADLF and structural data for (4-chlorophenyl)(2,2-/sup 2/H/sub 2/) acetic acid were used to obtain a preliminary value for the A parameter as 170.767 kHz.

Jackisch, M.A.; Jarrett, W.L.; Guo, K.; Fronczek, F.R.; Butler, L.G.

1988-01-20

161

Effects of Trimetazidine on Acetic Acid-Induced Colitis in Female Swiss Rats  

Microsoft Academic Search

Induction of colitis by acetic acid (A A) in the rat is widely used experimental model of inflammatory bowel disease (IBD) and ulcerations. AA as an irritant induces colitis involving infiltration of colonic mucosa with neutrophils and increased production of inflammatory mediators, such as hydrogen peroxide (H 2 O 2 ), nitric oxide (NO), myeloperoxidase activity (MPO), and tumor necrosis

Filiz Kuralay; Co?kun Yildiz; Omer Ozutemiz; Huray Islekel; Sezer Caliskan; Basak Bingol; Sermin Ozkal

2003-01-01

162

[Determination of five halogenated acetic acids in water using ion chromatography].  

PubMed

The five halogenated acetic acids (HAAs), monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), trichloro acetic acid (TCAA), monobromoacetic acid (MBAA), dibromoacetic acid (DBAA), were separated on an IonPac AS19 column specially designed for oxyhalides, and the separating conditions were optimized. DCAA and nitrite were separated by controlling the temperature. TCAA and sulfate were well separated rapidly by the concentration gradient of mobile phase. The interfering of carbonate (bicarbonate) was eliminated by the method of neutralization vacuum exhausting gas. The experimental results showed that the five HAAs, nitrite, bromide, nitrate, sulfate, etc. can be separated and detected simultaneously, and the detection limits of the DCAA and TCAA were 2.50 microg/L and 3.75 microg/L respectively, and the linearity ranges were from 10.0 to 2000.0 microg/L with the correlation coefficients of 0.999. The method is satisfied for the determination of drinking water. PMID:18438039

Gui, Jianye; Zhang, Lin

2008-01-01

163

Calibration and intercomparison of acetic acid measurements using proton transfer reaction mass spectrometry (PTR-MS)  

NASA Astrophysics Data System (ADS)

Acetic acid is one of the most abundant organic acids in the ambient atmosphere, with maximum mixing ratios reaching into the tens of parts per billion by volume (ppbv) range. The identities and associated magnitudes of the major sources and sinks for acetic acid are poorly characterized, due in part to the limitation in available measurement techniques. This paper demonstrates that Proton Transfer Reaction Mass Spectrometry (PTR-MS) can reliably quantify acetic acid vapor in ambient air. Three different PTR-MS configurations were calibrated at low ppbv mixing ratios using permeation tubes, which yielded calibration factors between 7.0 and 10.9 normalized counts per second per ppbv (ncps ppbv-1) at a drift tube field strength of 132 townsend (Td). Detection limits ranged from 0.06 to 0.32 ppbv with dwell times of 5 s. These calibration factors showed negligible humidity dependence. Using the experimentally determined calibration factors, PTR-MS measurements of acetic acid during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) campaign were validated against results obtained using Mist Chambers coupled with Ion Chromatography (MC/IC). An orthogonal least squares linear regression of paired data yielded a slope of 1.14 ± 0.06 (2?), an intercept of 0.049 ± 20 (2?) ppbv, and an R2 of 0.78. The median mixing ratio of acetic acid on Appledore Island, ME during the ICARTT campaign was 0.530 ± 0.025 ppbv with a minimum of 0.075 ± 0.004 ppbv, and a maximum of 3.555 ± 0.171 ppbv.

Haase, K. B.; Keene, W. C.; Pszenny, A. A. P.; Mayne, H. R.; Talbot, R. W.; Sive, B. C.

2012-07-01

164

Loading of amphipathic weak acids into liposomes in response to transmembrane calcium acetate gradients.  

PubMed

We describe a novel procedure to load amphipathic weak acid molecules into preformed liposomes. Differences in calcium acetate concentrations across the liposomal membrane induce an increase of the internal pH. This pH imbalance serves as an efficient driving force to load and accumulate weak acids (5(6)-carboxyfluorescein and nalidixic acid) inside the lipid vesicles. The mechanism of loading and the relevance of the method in drug delivery systems are discussed. PMID:8541297

Clerc, S; Barenholz, Y

1995-12-13

165

Loading of amphipathic weak acids into liposomes in response to transmembrane calcium acetate gradients  

Microsoft Academic Search

We describe a novel procedure to load amphipathic weak acid molecules into preformed liposomes. Differences in calcium acetate concentrations across the liposomal membrane induce an increase of the internal pH. This pH imbalance serves as an efficient driving force to load and accumulate weak acids (5(6)-carboxyfluorescein and nalidixic acid) inside the lipid vesicles. The mechanism of loading and the relevance

Stéphane Clerc; Yechezkel Barenholz

1995-01-01

166

A Possible Source of Error in the Chemical Detection of Indolyl Acetic Acid in Plants  

Microsoft Academic Search

DURING investigations on the growth substances of fruits of cacao and bananas (Musa spp.), it was of interest to find that a substance was present in seeded bananas which gave a pink colour with ferric chloride\\/perchloric acid or p-dimethyl amino-benz-aldehyde\\/hydrochloric acid, corresponding to the RF of indolyl acetic acid and to the zone of bioassay using the wheat coleoptile straight-growth

R. Nichols

1958-01-01

167

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

168

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

169

Computer aided design of reactive distillation processes for the treatment of waste waters polluted with acetic acid  

Microsoft Academic Search

A theoretical study of reactive distillation processes to remove acetic acid from its 30wt% aqueous solution by esterification with n-butanol is presented. Two different column structures were identified rendering theoretically close to 100 percent conversion of acetic acid. A model capable of precisely predicting the potential phase split is used. Total costs for the new processes are estimated and compared

Jignesh Gangadwala; G. Radulescu; Achim Kienle; K. Sundmacher

2007-01-01

170

Kinetic analysis on formation of poly(3-hydroxybutyrate) from acetic acid by Ralstonia eutropha under chemically defined conditions  

Microsoft Academic Search

  Batch cultures of Ralstonia eutropha in chemically defined media with acetic acid (HAc) as the sole carbon source were conducted to investigate acetate utilization,\\u000a formation of poly(3-hydroxybutyrate) (PHB) and growth of active biomass (ABM) under different carbon to nitrogen (C\\/N) weight\\u000a ratios. The specific acetate utilization rate based on ABM approached 0.16 g\\/g ABM h?1, which was not affected very

J Wang; J Yu

2001-01-01

171

Mechanisms of acetate formation and acetate activation in halophilic archaea  

Microsoft Academic Search

The halophilic archaea Halococcus (Hc.) saccharolyticus, Haloferax (Hf.) volcanii, and Halorubrum (Hr.) saccharovorum were found to generate acetate during growth on glucose and to utilize acetate as a growth substrate. The mechanisms of acetate formation from acetyl-CoA and of acetate activation to acetyl-CoA were studied. Hc. saccharolyticus, exponentially growing on complex medium with glucose, formed acetate and contained ADP-forming acetyl-CoA

Christopher Bräsen; Peter Schönheit

2001-01-01

172

[Concentrations and acidity contributions of acetate and formate in precipitation at 14 stations of China].  

PubMed

To investigate the concentrations of organic acids in precipitation in China and their contributions to the total acidity of precipitation, samples were taken at 14 stations of regional representativeness in 2007 and analyzed for acetate and formate using ion chromatography. In this paper, data of acetate and formate in precipitation at 14 stations are presented, wet depositions of these organic acids are calculated, and contributions of them to the total free acidity (TFA) of precipitation are estimated. Based on the measurements, the mean concentrations of formate at different stations were in the range of 0.96-3.43 micromol/L, and those of acetate in the range of 0-5.13 micromol/L, close to the levels at remote sites in other countries and at the lower ends of concentration ranges from previous measurements in China. Comparisons indicate that the concentrations of the organic acids at remote sites are lower than those at sites in the vicinity of urban areas. The annual wet depositions of formate and acetate were estimated to be in the ranges of 0.38-4.18 mmol/(m2 x a) and 0.06-5.87 mmol/(m2 x a), respectively, with larger depositions in southern China and smaller depositions in northern China. The relative contributions of the two organic acids to the TFA of precipitation were estimated to be in the range of 0.02%-51.6%, with an overall average of 2.95%. This suggests that although acid rain in China is mainly caused by emissions of sulfur and nitrogen oxides, organic acids can significantly contribute to the acidification of precipitation in some regions and during some periods, hence need to be included in observational studies of acid rain. PMID:20527162

He, Xiao-huan; Xu, Xiao-bin; Yu, Xiao-lan; Tang, Jie

2010-04-01

173

Stimulation of fatty acid synthesis by 4?-phorbol-12-myristate-13-acetate in isolated rat hepatocytes  

Microsoft Academic Search

The tumor-promoting agent 4?-phorbol-12-myristate-13-acetate (TPA) is shown to be a potent stimulator of fatty acid synthesis\\u000a in isolated rat hepatocytes. The maximal effect of TPA is seen at 10?6 M, and the concentration for half-maximal effect is ca. 10?8 M. Stimulation of fatty acid synthesis by TPA is shown not to require the presence of extracellular Ca++. TPA produces a

Takahide Nomura; Masakatsu Tachibana; Hiroko Nomura; Yasumichi Hagino

1986-01-01

174

Interaction of ethylene with indole-3-acetic acid in regulation of rooting in pea cuttings  

Microsoft Academic Search

Cuttings of pea (Pisum sativum L. cv Marma) were treated with 1-aminocyclopropane-l-carboxylic acid (ACC). This treatment caused increased ethylene production and reduction of root formation. The effect of 0.1 mM ACC on the level of endogenous indole-3-acetic acid (IAA) in the rooting zone and in the shoot apex was analyzed by gas chromatography-single ion monitoring mass spectrometry or by high

A.-C. Nordstrom; L. Eliasson

1993-01-01

175

Microwave Spectroscopy and Proton Transfer Dynamics in the Formic Acid-Acetic Acid Dimer  

NASA Astrophysics Data System (ADS)

The rotational spectrum of the doubly hydrogen-bonded {hetero} dimer formed between formic acid and acetic acid has been recorded between 4 and 18 GHz using a pulsed-nozzle Fourier transform microwave spectrometer. Each rigid-molecule rotational transition is split into four as a result of two concurrent tunnelling motions, one being proton transfer between the two acid molecules, and the other the torsion/rotation of the methyl group within the acetic acid. We present a full assignment of the spectrum for {J} = 1 to {J} = 7 for these four torsion/tunnelling states. Spectra have been observed for the main isotopic species, with deuterium substitution at the C of the formic acid and all 13C species in natural abundance, The observed transitions are fitted to within a few kilohertz using a molecule-fixed effective rotational Hamiltonian for the separate {A} and {E} vibrational species of the G12 permutation-inversion group which is applicable to this complex. To reduce the effects of internal angular momentum, a non-principal axis system is used throughout. Interpretation of the internal motion uses an internal-vibration and overall rotation scheme, and full sets of rotational and centrifugal distortion constants are determined. The proton tunnelling rates and the internal angular momentum of the methyl group in the {E} states is interpreted in terms of a dynamical model which involves coupled proton transfer and internal rotation. The resulting potential energy surface not only describes these internal motions, but can also explain the observed shifts in rotational constants between {A} and {E} species, and the deviations of the tunnelling frequencies from the expected 2:1 ratio. It also permits the determination of spectral constants free from the contamination effects of the internal dynamics. M.C.D. Tayler, B. Ouyang and B.J. Howard, J. Chem. Phys., {134}, 054316 (2011).

Howard, B. J.; Steer, E.; Page, F.; Tayler, M.; Ouyang, B.; Leung, H. O.; Marshall, M. D.; Muenter, J. S.

2012-06-01

176

Exogenous treatment with indole-3-acetic acid and salicylic acid alleviates cadmium toxicity in wheat seedlings.  

PubMed

The seedlings of wheat were grown in the presence of CdCl2 (500 or 1000 ?M Cd), were applied with 500 ?M of indole-3-acetic acid (IAA) or 500 ?M salicylic acid (SA) as seed soaking and were sampled at 56 days after sowing. The plants exposed to Cd exhibited a substantial decline in growth, pigment content, relative water content (RWC) activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) and leaf structure. However, pretreatment with IAA or SA mitigated the stress generated by Cd and markedly improved the aforesaid parameters. The Cd increased proline content, electrolyte leakage and plant Cd content. However, the IAA or SA treatment attenuated the adverse effects of Cd on these attributes. The results showed that pretreatment with IAA or SA enhanced the antioxidant defense activities in Cd stressed wheat, thus alleviating Cd induced oxidative damage and enhancing Cd tolerance and leaf anatomy. PMID:23684274

Agami, Ramadan A; Mohamed, Gamal F

2013-08-01

177

Dykellic Acid Inhibits Phorbol Myristate Acetate-induced Matrix Metalloproteinase- 9 Expression by Inhibiting Nuclear Factor B Transcriptional Activity1  

Microsoft Academic Search

Proteolytic degradation of the extracellular matrix and tumor metas- tasis correlate with expression of endopeptidases known as matrix metal- loproteinases (MMPs). Expression of MMPs is regulated by cytokines and signal transduction pathways, including those activated by phorbol my- ristate acetate. We found that dykellic acid, a fungal metabolite, signifi- cantly inhibits the phorbol myristate acetate-induced increase in MMP-9 expression and

Ju-Hyung Woo; Jong-Wook Park; Sung-Hee Lee; Young-Ho Kim; In Kyu Lee; Edward Gabrielson; Sang-Han Lee; Ho-Jae Lee; Yung-Hee Kho; Taeg Kyu Kwon

2003-01-01

178

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

179

Preparation of macroporous lime from natural lime by swelling method with acetic acid for high-temperature desulfurization  

Microsoft Academic Search

To develop a highly active calcium oxide high-temperature desulfurization sorbent, a method of preparation of macroporous calcium oxides from lime was studied. This method is composed of two steps: swelling of the lime and calcination of the swelled sample. Swelling occurred when lime was exposed to the vapor of acetic acid. The swelling resulted from calcium acetate formation in the

Eiji Sasaoka; Norimasa Sada

1998-01-01

180

Formic and acetic acid over the central Amazon region, Brazil. I - Dry season  

NASA Technical Reports Server (NTRS)

The concentrations of formic and acetic acids in the gas phase, atmospheric aerosol, and rainwater samples collected in Amazonia at ground level and in the atmosphere during the Amazon Boundary Layer Experiment in July/August 1985 were analyzed by ion exchange chromatography. The diurnal behavior of both acids at ground level and their vertical distribution in the forest canopy point to the existence of vegetative sources as well as to production by chemical reactions in the atmosphere. The concentrations of formic and acetic acids in the gas phase were about 2 orders of magnitude higher than the corresponding concentrations in the atmospheric aerosol. In rainwater, the total formate and acetate represented about one half of the anion equivalents, in contrast to less than 10 percent of the soluble anionic equivalents contributed by these acids in the atmospheric aerosol. The observed levels of these ions in rainwater are considered to be the result of a combination of chemical reactions in hydrometeors and the scavenging of the gaseous acids by cloud droplets.

Andreae, M. O.; Andreae, T. W.; Talbot, R. W.; Harriss, R. C.

1988-01-01

181

Effects of acetic acid and lactic acid on physicochemical characteristics of native and cross-linked wheat starches.  

PubMed

The effects of two common organic acids; lactic and acetic acids (150 mg/kg) on physicochemical properties of native and cross-linked wheat starches were investigated prior and after gelatinization. These acids caused formation of some cracks and spots on the granules. The intrinsic viscosity of both starches decreased in the presence of the acids particularly after gelatinization. Water solubility increased while water absorption reduced after addition of the acids. The acids caused reduction in gelatinization temperature and enthalpy of gelatinization of both starches. The starch gels became softer, less cohesive, elastic and gummy when acids were added. These changes may indicate the degradation of the starch molecules by the acids. Cross-linked wheat starch was more resistant to the acids. However, both starches became more susceptible to the acids after gelatinization. The effect of lactic acid on physicochemical properties of both starches before and after gelatinization was greater than acetic acid. PMID:24206724

Majzoobi, Mahsa; Beparva, Paniz

2014-03-15

182

Clostridium strain which produces acetic acid from waste gases  

DOEpatents

A method and apparatus are disclosed for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration. 4 figs.

Gaddy, J.L.

1997-01-14

183

Novel wine yeast with mutations in YAP1 that produce less acetic acid during fermentation.  

PubMed

Acetic acid, a byproduct formed during yeast alcoholic fermentation, is the main component of volatile acidity (VA). When present in high concentrations in wine, acetic acid imparts an undesirable 'vinegary' character that results in a significant reduction in quality and sales. Previously, it has been shown that saké yeast strains resistant to the antifungal cerulenin produce significantly lower levels of VA. In this study, we used a classical mutagenesis method to isolate a series of cerulenin-resistant strains, derived from a commercial diploid wine yeast. Four of the selected strains showed a consistent low-VA production phenotype after small-scale fermentation of different white and red grape musts. Specific mutations in YAP1, a gene encoding a transcription factor required for oxidative stress tolerance, were found in three of the four low-VA strains. When integrated into the genome of a haploid wine strain, the mutated YAP1 alleles partially reproduced the low-VA production phenotype of the diploid cerulenin-resistant strains, suggesting that YAP1 might play a role in (regulating) acetic acid production during fermentation. This study offers prospects for the development of low-VA wine yeast starter strains that could assist winemakers in their effort to consistently produce wine to definable quality specifications. PMID:23146134

Cordente, Antonio G; Cordero-Bueso, Gustavo; Pretorius, Isak S; Curtin, Christopher D

2013-02-01

184

DFT computation and experimental analysis of vibrational and electronic spectra of phenoxy acetic acid herbicides  

NASA Astrophysics Data System (ADS)

An absolute vibrational analysis has been attempted on the basis of experimental FTIR and NIR-FT Raman spectra with calculated vibrational wavenumbers and intensities of phenoxy acetic acids. The equilibrium geometry, bonding features and harmonic vibrational wavenumbers have been calculated with the help of B3LYP method with Dunning correlation consistent basis set aug-cc-pVTZ. The electronic structures of molecular fragments were described in terms of natural bond orbital analysis, which shows intermolecular Osbnd H⋯O and intramolecular Csbnd H⋯O hydrogen bonds. The electronic absorption spectra with different solvents have been investigated in combination with time-dependent density functional theory calculation. The pKa values of phenoxy acetic acids were compared.

Arul Dhas, D.; Hubert Joe, I.; Roy, S. D. D.; Balachandran, S.

2013-05-01

185

Pharmacological activity of 2% aqueous acetic acid extract of Alhagi maurorum roots  

Microsoft Academic Search

A 2% aqueous acetic acid extract of Alhagi maurorum powdered roots was examined for its pharmacological activity and showed the following results: (1) Administration of the extract intraperitoneally into mice decreased the body temperature in a dose dependent manner. The decreases ranged from 2.5 to 7.3°C. (2) Treatment of the frog rectus abdominis muscle with the extract in doses of

M. S. Marashdah; A. I. Farraj

2010-01-01

186

5,6-Dimethylxanthenone-4Acetic Acid (DMXAA): a New Biological Response Modifier for Cancer Therapy  

Microsoft Academic Search

The investigational anti-cancer drug5,6-dimethylxanthenone-4-acetic acid(DMXAA) was developed by the AucklandCancer Society Research Centre (ACSRC). Ithas recently completed Phase I trials inNew Zealand and UK under the direction ofthe Cancer Research Campaign's Phase I\\/IIClinical Trials Committee. As a biologicalresponse modifier, pharmacological andtoxicological properties of DMXAA areremarkably different from most conventionalchemotherapeutic agents. Induction ofcytokines (particularly tumour necrosisfactor (TNF-a), serotonin and nitricoxide (NO)),

Shufeng Zhou; Philip Kestell; Bruce C. Baguley; James W. Paxton

2002-01-01

187

Indole-3-acetic acid (IAA) production by Arthrobacter species isolated from Azolla.  

PubMed

Arthrobacter species, isolated from the leaf cavities and the microsporocarps of the aquatic fern species Azolla pinnata and Azolla filiculoides, produced indole-3-acetic acid (IAA) in culture when the precursor tryptophan was added to the medium. No IAA production was detected in the absence of tryptophan. Maximum IAA formation was obtained in the first 2 d of incubation. Part of the tryptophan was transformed to N alpha-acetyl-L-tryptophan. PMID:1564446

Forni, C; Riov, J; Grilli Caiola, M; Tel-Or, E

1992-02-01

188

Influence of the carrier on steam reforming of acetic acid over Ru-based catalysts  

Microsoft Academic Search

The reaction of steam reforming of acetic acid (HAc), a model compound of pyrolysis-oil, over ruthenium catalysts supported on Al2O3 and MgO\\/Al2O3 carriers has been investigated employing transient and steady-state techniques. Main objective is the establishment of the reaction network over a wide temperature range and the elucidation of the role of MgO on intrinsic catalytic activity. It has been

Aristides C. Basagiannis; Xenophon E. Verykios

2008-01-01

189

Effect of different fertilization treatments on indole-3-acetic acid producing bacteria in soil  

Microsoft Academic Search

Purpose  Soil microorganisms directly affect the growth of plants. Especially, plant growth-promoting rhizobacteria (PGPR) play an\\u000a important role in plant growth. There are many studies about the effects of different fertilization treatments on soil microbial\\u000a community structure; however, the effects on PGPR, including indole-3-acetic acid (IAA)-producing bacteria have not been previously\\u000a reported. The objective of this study is to determine the

Chao-Lei Yuan; Cheng-Xiang Mou; Wen-Liang Wu; Yan-Bin Guo

2011-01-01

190

Recent developments in the selective oxidation of propane to acrylic and acetic acids  

Microsoft Academic Search

The oxidation of propane to acrylic and acetic acids has been studied using a Mo1Nb0.08Sb0.25V0.3 mixed oxide catalyst, calcined and activated before reaction under different conditions (T=500 or 600°C in atmospheres of N2, static air, and flowing air (dry or with water or ammonia addition)). Catalytic testing was performed at 400°C in a plug flow microreactor and the characterisation of

J. C. Védrine; E. K. Novakova; E. G. Derouane

2003-01-01

191

Direct catalytic conversion of methane to acetic acid in an aqueous medium  

Microsoft Academic Search

ALTHOUGH methane is the most-abundant of alkanes, hazards of handling and distribution prevent known methane reserves1,2 from being fully exploited. Moreover, it is the least reactive alkane, so whereas selective conversion to more useful chemical products would be of great value, it is difficult to achieve. A useful target molecule for methane conversion is acetic acid, but existing approaches to

Minren Lin; Ayusman Sen

1994-01-01

192

Acetic acid conditioning stimulus induces long-lasting antinociception of somatic inflammatory pain  

Microsoft Academic Search

A wide variety of noxious stimuli are known to induce a powerful inhibition of pain sensation evoked at a remote region of the body. Here we show that an intraperitoneal acetic acid (AA) conditioning stimulus produces long-lasting inhibition of formalin-evoked somatic inflammatory pain behavior in mice. This novel long-lasting antinociception was completely blocked by the 5-hydroxytryptamine type 2A\\/2C (5-HT2A\\/2C) receptor

Takashi Kurihara; Takahiro Nonaka; Tsutomu Tanabe

2003-01-01

193

On the unusual IR spectra of the acetic acid-trimethylamine complex in low temperature matrices  

NASA Astrophysics Data System (ADS)

Usually the stretching vibration of the A-H group in hydrogen-bonded complexes gives an intense, broad absorption in the IR spectrum. However in a few complexes it has proved difficult to detect this absorption in low temperature matrices. In this work the Ratajczak-Yaremko vibrational model of the hydrogen bond has been applied to simulate the IR spectrum obtained for one such complex: the acetic acid-trimethylamine, ACA-TMA, hydrogen bonded complex isolated in an argon matrix.

Ratajczak, Henryk; Wierzejewska, Maria; Barnes, Austin J.; Yaremko, Anatoly M.; Virko, Serdej V.

2014-06-01

194

Alkaline pre-treatment of rice hulls for hydrothermal production of acetic acid  

Microsoft Academic Search

To solve the blockage caused by silica during the hydrothermal conversion of rice hulls into acetic acid in a continuous-flow reactor, the removal of silica from rice hulls and the retainment of organics by alkaline extraction were carried out in a range of pH values from 5 to 12 and temperatures from 30 to 85°C. It was found that the

Yamin Hsieh; Yingxun Du; Fangming Jin; Zhouyu Zhou; Heiji Enomoto

2009-01-01

195

Reductions of aldehydes and ketones with a readily available N-heterocyclic carbene borane and acetic acid  

PubMed Central

Summary Acetic acid promotes the reduction of aldehydes and ketones by the readily available N-heterocyclic carbene borane, 1,3-dimethylimidazol-2-ylidene borane. Aldehydes are reduced over 1–24 h at room temperature with 1 equiv of acetic acid and 0.5 equiv of the NHC-borane. Ketone reductions are slower but can be accelerated by using 5 equiv of acetic acid. Aldehydes can be selectively reduced in the presence of ketones. On a small scale, products are isolated by evaporation of the reaction mixture and direct chromatography.

Lamm, Vladimir; Pan, Xiangcheng

2013-01-01

196

Uncoupling by Acetic Acid Limits Growth of and Acetogenesis by Clostridium thermoaceticum  

PubMed Central

When cells of the anaerobic thermophile Clostridium thermoaceticum grow in batch culture and homoferment glucose to acetic acid, the pH of the medium decreases until growth and then acid production cease, at about pH 5. We postulated that the end product of fermentation limits growth by acting as an uncoupling agent. Thus, when the pH of the medium is low, the cytoplasm of the cells becomes acidified below a tolerable pH. We have therefore measured the internal pH of growing cells and compared these values with those of nongrowing cells incubated in the absence of acetic acid. Growing cells maintained an interior about 0.6 pH units more alkaline than the exterior throughout most of batch growth (i.e., ?pH = 0.6). We also measured the transmembrane electrical potential (??), which decreased from 140 mV at pH 7 at the beginning of growth to 80 mV when the medium had reached pH 5. The proton motive force, therefore, was 155 mV at pH 7, decreasing to 120 mV at pH 5. When further fermentation acidified the medium below pH 5, both the ?pH and the ?? collapsed, indicating that these cells require an internal pH of at least 5.5 to 5.7. Cells harvested from stationary phase and suspended in citrate-phosphate buffer maintained a ?pH of 1.5 at external pH 5.0. This ?pH was dissipated by acetic acid (at the concentrations found in the growth medium) and other weak organic acids, as well as by ionophores and inhibitors of glycolysis and of the H+-ATPase. Nongrowing cells had a ?? which ranged from about 116 mV at external pH 7 to about 55 mV at external pH 5 and which also was sensitive to ionophores. Since acetic acid, in its un-ionized form, diffuses passively across the cytoplasmic membrane, it effectively renders the membrane permeable to protons. It therefore seems unlikely that mutations at one or a few loci would result in C. thermoaceticum cells significantly more acetic acid tolerant than their parental type.

Baronofsky, Jerald J.; Schreurs, Wilhelmus J. A.; Kashket, Eva R.

1984-01-01

197

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

198

Nitric oxide: its production in host-cell-infiltrated EMT6 spheroids and its role in tumour cell killing by flavone-8-acetic acid and 5,6-dimethylxanthenone-4-acetic acid  

Microsoft Academic Search

Flavone-8-acetic acid (FAA) and its more dose-potent analogue 5,6-dimethylxanthenone-4-acetic acid (5,6-MeXAA), appear to exert their antitumour effects through vascular and other host-mediated mechanisms and are known to induce the synthesis of nitric oxide by murine macrophages. We investigated the role of nitric oxide in the cytotoxic effects of these drugs in host-cell-infiltrated spheroids. EMT6 murine mammary adenocarcinoma cells were grown

Lindy L. Thomsen; Bruce C. Baguleyl; W. R. Wilson

1992-01-01

199

Characterization of acetic acid bacteria in traditional acetic acid fermentation of rice vinegar (komesu) and unpolished rice vinegar (kurosu) produced in Japan.  

PubMed

Bacterial strains were isolated from samples of Japanese rice vinegar (komesu) and unpolished rice vinegar (kurosu) fermented by the traditional static method. Fermentations have never been inoculated with a pure culture since they were started in 1907. A total of 178 isolates were divided into groups A and B on the basis of enterobacterial repetitive intergenic consensus-PCR and random amplified polymorphic DNA fingerprinting analyses. The 16S ribosomal DNA sequences of strains belonging to each group showed similarities of more than 99% with Acetobacter pasteurianus. Group A strains overwhelmingly dominated all stages of fermentation of both types of vinegar. Our results indicate that appropriate strains of acetic acid bacteria have spontaneously established almost pure cultures during nearly a century of komesu and kurosu fermentation. PMID:11157275

Nanda, K; Taniguchi, M; Ujike, S; Ishihara, N; Mori, H; Ono, H; Murooka, Y

2001-02-01

200

Characterization of Acetic Acid Bacteria in Traditional Acetic Acid Fermentation of Rice Vinegar (Komesu) and Unpolished Rice Vinegar (Kurosu) Produced in Japan  

PubMed Central

Bacterial strains were isolated from samples of Japanese rice vinegar (komesu) and unpolished rice vinegar (kurosu) fermented by the traditional static method. Fermentations have never been inoculated with a pure culture since they were started in 1907. A total of 178 isolates were divided into groups A and B on the basis of enterobacterial repetitive intergenic consensus-PCR and random amplified polymorphic DNA fingerprinting analyses. The 16S ribosomal DNA sequences of strains belonging to each group showed similarities of more than 99% with Acetobacter pasteurianus. Group A strains overwhelmingly dominated all stages of fermentation of both types of vinegar. Our results indicate that appropriate strains of acetic acid bacteria have spontaneously established almost pure cultures during nearly a century of komesu and kurosu fermentation.

Nanda, Kumiko; Taniguchi, Mariko; Ujike, Satoshi; Ishihara, Nobuhiro; Mori, Hirotaka; Ono, Hisayo; Murooka, Yoshikatsu

2001-01-01

201

Fed-batch fermentation with and without on-line extraction for propionic and acetic acid production by Propionibacterium acidipropionici.  

PubMed

Fed-batch propionic and acetic acid fermentations were performed in semi-defined laboratory medium and in corn steep liquor with Propionibacterium acidipropionici strain P9. On average, over four experiments, 34.5 milligrams propionic acid and 12.8 milligrams acetic acid were obtained in about 146 h in laboratory medium with 79 milligrams glucose added over five feeding periods. The highest concentration of propionic acid, 45 milligrams, was obtained when the glucose concentration was not allowed to drop to zero. In corn steep liquor 35 milligrams propionic acid and 11 milligrams acetic acid were produced in 108 h from 59.4 milligrams total lactic acid provided as seven feedings of corn steep liquor. Extractive fed-batch fermentations were conducted in semi-defined medium using either flat-sheet-supported liquid membranes or hollow-fiber membrane extraction to remove organic acids from the culture medium. As operated during the course of the fermentation, these systems extracted 25% and 22% of the acetic acid and 36.5% and 44.5% of the propionic acid, respectively, produced in the fermentation. Total amounts of acids produced were about the same as in comparable nonextractive fermentations: 30-37 milligrams propionic acid and 13 milligrams acetic acid were produced in 150 h. Limitations on acid production can be attributed to limited substrate feed, not to failure of the extraction system. PMID:8867628

Ozadali, F; Glatz, B A; Glatz, C E

1996-02-01

202

Restoration of Normal Glutamic Acid Transport in Vitamin B6-Deficient Lactobacillus Plantarum by Acetate, Ammonium, and Vitamin B6.  

National Technical Information Service (NTIS)

A vitamin B6-deficiency in Lactobacillus plantarum markedly reduces the amount of glutamate and other amino acids which can be taken up and accumulated from buffered solutions. The capacity for glutamate accumulation is restored to normal levels when acet...

J. T. Holden

1964-01-01

203

Efficient Synthesis of Primary Amides from Carboxylic Acids using N,N?-Carbonyldiimidazole and Ammonium Acetate in Ionic Liquid  

Microsoft Academic Search

A novel and efficient method for the conversion of carboxylic acids to primary amides using N,N?-carbonyldiimidazole in combination with ammonium acetate\\/triethyl amine system in [BMIM]BF4 is developed.

Kwan Soo Lee; Kee D. Kim

2011-01-01

204

Vapor–liquid equilibria for water + acetic acid + ( N, N-dimethylformamide or dimethyl sulfoxide) at 13.33 kPa  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data of the systems acetic acid+N,N-dimethylformamide (DMF), acetic acid+dimethyl sulfoxide (DMSO), DMSO+water, water+acetic acid+DMF, and water+acetic acid+DMSO have been measured at 13.33kPa by using an improved Rose equilibrium still. The association of acetic acid in vapor phase has been considered, and the nonideality of vapor phase was accounted for using the Hayden–O’Connell (HOC) method. The experimental

Yong Peng; Lijuan Ping; Shengli Lu; Jianwei Mao

2009-01-01

205

Radiation sterilization of hydrocortisone acetate.  

National Technical Information Service (NTIS)

The feasibility of using high energy ionizing radiation for the sterilization of hydrocortisone acetate was investigated. Hydrocortisone acetate in the form of powder was exposed to different dose levels of gamma radiation using a Cobalt-60 source. The ir...

A. Charef A. Boussaha

1989-01-01

206

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

Microsoft Academic Search

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

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

1996-01-01

207

Acetate Production by Methanogenic Bacteria  

PubMed Central

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

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

1989-01-01

208

Mutants of the pentose-fermenting yeast Pachysolen tannophilus tolerant to hardwood spent sulfite liquor and acetic acid.  

PubMed

A strain development program was initiated to improve the tolerance of the pentose-fermenting yeast Pachysolen tannophilus to inhibitors in lignocellulosic hydrolysates. Several rounds of UV mutagenesis followed by screening were used to select for mutants of P. tannophilus NRRL Y2460 with improved tolerance to hardwood spent sulfite liquor (HW SSL) and acetic acid in separate selection lines. The wild type (WT) strain grew in 50 % (v/v) HW SSL while third round HW SSL mutants (designated UHW301, UHW302 and UHW303) grew in 60 % (v/v) HW SSL, with two of these isolates (UHW302 and UHW303) being viable and growing, respectively, in 70 % (v/v) HW SSL. In defined liquid media containing acetic acid, the WT strain grew in 0.70 % (w/v) acetic acid, while third round acetic acid mutants (designated UAA301, UAA302 and UAA303) grew in 0.80 % (w/v) acetic acid, with one isolate (UAA302) growing in 0.90 % (w/v) acetic acid. Cross-tolerance of HW SSL-tolerant mutants to acetic acid and vice versa was observed with UHW303 able to grow in 0.90 % (w/v) acetic acid and UAA302 growing in 60 % (v/v) HW SSL. The UV-induced mutants retained the ability to ferment glucose and xylose to ethanol in defined media. These mutants of P. tannophilus are of considerable interest for bioconversion of the sugars in lignocellulosic hydrolysates to ethanol. PMID:24122119

Harner, Nicole K; Bajwa, Paramjit K; Habash, Marc B; Trevors, Jack T; Austin, Glen D; Lee, Hung

2014-01-01

209

Dissociation constant of acetic acid in N-methylpropionamide from 5 to 55°C and related thermodynamic quantities  

Microsoft Academic Search

The dissociation constant of acetic acid in N-methylpropionamide (NMP) has been determined at 11 temperatures from 5 to 55°C by measurement of the electromotive force of cells without liquid junction containing hydrogen gas electrodes and silver-silver chloride electrodes. The pK at 25°C was found to be 7.995 (molal scale) as compared with 4.756 in water; thus, acetic acid is much

Edgar S. Etz; R. A. Robinson; Roger G. Bates

1972-01-01

210

Conductometric simultaneous determination of acetic acid, monochloroacetic acid and trichloroacetic acid using orthogonal signal correction-partial least squares.  

PubMed

A simultaneous conductometric titration method for determination of mixtures of acetic acid, monochloroacetic acid and trichloroacetic acid based on the multivariate calibration partial least squares is proposed. It is possible to obtain an adjustable model to relate squared concentration values of the mixtures used in the calibration range by conductance. The effect of orthogonal signal correction (OSC) as a preprocessing technique used to remove the information unrelated to the target variables is studied. The calibration model was build using conductometric titrations data of 16 mixtures of three acids. The concentration matrix was designed by a orthogonal design. The root mean squares error of prediction (RMSEP) for acetic acid, monochloroacetic acid and trichloroacetic acid with and without OSC were 0.08, 0.30 and 0.08, and 0.15, 0.40 and 0.18, respectively. The results obtained by OSC-PLS are better than the PLS and this indicate the successful application of the OSC filter as a good preprocessing method in multivariate calibration methods. The proposed procedure allows the simultaneous determination of these acids, in the synthetic mixtures. PMID:16236436

Ghorbani, R; Ghasemi, J; Abdollahi, B

2006-04-17

211

Acet-oxy-?-valerolactone  

PubMed Central

Levulinyl cellulose esters have been produced as an effective renewable binder for architectural coatings. The title compound, C7H10O4 (systematic name: 2-methyl-5-oxo­tetra­hydro­furan-2-yl acetate), assigned as the esterifying species, was isolated and crystallized to confirm the structure. In the crystal, the mol­ecules pack in layers parallel to (102) utilizing weak C—H?O inter­actions.

Tristram, Cameron; Gainsford, Graeme J.; Hinkley, Simon

2013-01-01

212

[Synthesis of ethriolophospholipids of acetal type].  

PubMed

New analogues of acetal-type phospholipids were obtained on the basis of ethriol (2-hydroxymethyl-2-ethyl-1,3-propanediol). The starting triol originally was condensed with decanal or dodecanal to form acetals, which were then phosphorylated with tetraethyldiamidophosphorous acid chloride. The amidophosphites were further oxidized with iodosobenzene or sulfurized to the corresponding acetal-type phospholipids and their thio analogues. PMID:17042275

Savin, G A

2006-01-01

213

Synthesis of Saturated Long Chain Fatty Acids from Sodium Acetate-1-C14 by Mycoplasma1  

PubMed Central

Three strains of Mycoplasma, M. laidlawii A and B, and Mycoplasma sp. A60549, were grown in broth containing sodium acetate-1-C14. The methyl esters of the phospholipid fatty acids of harvested radioactive cells were prepared and identified by comparison of their mobilities to known radioactive fatty acid methyl esters by use of a modified reversed-phase partition-thin layer chromatographic technique. No radioactive methyl oleate or methyl linoleate was detected. Compounds migrating as radioactive methyl myristate, stearate, palmitate, and, with less certainty, laurate and octanoate were detected. The qualitative findings for all three organisms appeared similar. M. laidlawii B synthesized a radioactive substance, presumably a saturated fatty acid detected as the methyl ester derivative, which migrated in a position intermediate to methyl myristate-1-C14 and methyl palmitate-1-C14. This work indicates that M. laidlawii A and B and Mycoplasma sp. A60549 are capable, in a complex medium containing fatty acids, of synthesizing saturated but not unsaturated fatty acids entirely or in part from acetate. Images

Pollack, J. D.; Tourtellotte, M. E.

1967-01-01

214

Plasma acetate turnover and oxidation.  

PubMed Central

Plasma acetate turnover and oxidation were determined in 11 healthy subjects by the constant infusion of a trace amount of [1-14C]acetate for 6 h. The subjects ages ranged from 22 to 57 yr. There was a positive correlation (P less than 0.001) between plasma acetate concentration and turnover rate, and a negative correlation (P less than 0.001) between turnover and age. The plasma acetate concentration in the subjects 22--28 yr old was 0.17 vs. 0.13 mM (P less than 0.02) in subjects 40--57 yr old. The plasma acetate turnover rate was also greater in the younger age group (8.23 +/- 0.66 vs. 4.98 +/- 0.64 mumol/min . kg, P less than 0.01). Approximately 90% of the plasma acetate turnover was immediately oxidized to CO2 in both age groups, however, 13.2 +/- 0.89% of the CO2 output in the younger group was derived from plasma acetate oxidation compared to 7.9 +/- 0.94% in the older group (P less than 0.01). The mean plasma acetate concentration, turnover, and oxidation in six cancer patients 47--63 yr old were similar to the values observed in the age-matched healthy subjects. Uptake or output of acetate by various tissues was measured by arterial-venous plasma acetate concentration differences. In seven of eight subjects undergoing elective surgery, the arterial-portal venous concentration difference was negative, which indicated that the gastrointestinal tract can contribute to plasma acetate production. Uptake of plasma acetate by both the leg and liver appeared to be dictated by the arterial acetate concentration. Net production of acetate by both the leg and liver was most often observed at arterial plasma acetate concentrations less than 0.08 mM.

Skutches, C L; Holroyde, C P; Myers, R N; Paul, P; Reichard, G A

1979-01-01

215

The short-chain fatty acid acetate reduces appetite via a central homeostatic mechanism  

PubMed Central

Increased intake of dietary carbohydrate that is fermented in the colon by the microbiota has been reported to decrease body weight, although the mechanism remains unclear. Here we use in vivo11C-acetate and PET-CT scanning to show that colonic acetate crosses the blood–brain barrier and is taken up by the brain. Intraperitoneal acetate results in appetite suppression and hypothalamic neuronal activation patterning. We also show that acetate administration is associated with activation of acetyl-CoA carboxylase and changes in the expression profiles of regulatory neuropeptides that favour appetite suppression. Furthermore, we demonstrate through 13C high-resolution magic-angle-spinning that 13C acetate from fermentation of 13C-labelled carbohydrate in the colon increases hypothalamic 13C acetate above baseline levels. Hypothalamic 13C acetate regionally increases the 13C labelling of the glutamate–glutamine and GABA neuroglial cycles, with hypothalamic 13C lactate reaching higher levels than the ‘remaining brain’. These observations suggest that acetate has a direct role in central appetite regulation.

Frost, Gary; Sleeth, Michelle L.; Sahuri-Arisoylu, Meliz; Lizarbe, Blanca; Cerdan, Sebastian; Brody, Leigh; Anastasovska, Jelena; Ghourab, Samar; Hankir, Mohammed; Zhang, Shuai; Carling, David; Swann, Jonathan R.; Gibson, Glenn; Viardot, Alexander; Morrison, Douglas; Louise Thomas, E; Bell, Jimmy D.

2014-01-01

216

The short-chain fatty acid acetate reduces appetite via a central homeostatic mechanism.  

PubMed

Increased intake of dietary carbohydrate that is fermented in the colon by the microbiota has been reported to decrease body weight, although the mechanism remains unclear. Here we use in vivo(11)C-acetate and PET-CT scanning to show that colonic acetate crosses the blood-brain barrier and is taken up by the brain. Intraperitoneal acetate results in appetite suppression and hypothalamic neuronal activation patterning. We also show that acetate administration is associated with activation of acetyl-CoA carboxylase and changes in the expression profiles of regulatory neuropeptides that favour appetite suppression. Furthermore, we demonstrate through (13)C high-resolution magic-angle-spinning that (13)C acetate from fermentation of (13)C-labelled carbohydrate in the colon increases hypothalamic (13)C acetate above baseline levels. Hypothalamic (13)C acetate regionally increases the (13)C labelling of the glutamate-glutamine and GABA neuroglial cycles, with hypothalamic (13)C lactate reaching higher levels than the 'remaining brain'. These observations suggest that acetate has a direct role in central appetite regulation. PMID:24781306

Frost, Gary; Sleeth, Michelle L; Sahuri-Arisoylu, Meliz; Lizarbe, Blanca; Cerdan, Sebastian; Brody, Leigh; Anastasovska, Jelena; Ghourab, Samar; Hankir, Mohammed; Zhang, Shuai; Carling, David; Swann, Jonathan R; Gibson, Glenn; Viardot, Alexander; Morrison, Douglas; Louise Thomas, E; Bell, Jimmy D

2014-01-01

217

Metabolism of Indole-3-Acetic Acid by Pericarp Discs from Immature and Mature Tomato (Lycopersicon esculentum Mill) 1  

PubMed Central

[1?-14C, 13C6]Indole-3-acetic acid was infiltrated into immature pericarp discs from fruits of tomato (Lycopersicon esculentum Mill., cv Moneymaker). After a 24-h incubation period the discs were extracted with methanol and the partially purified extract was analyzed by reversed-phase high-performance liquid chromatography-radiocounting. Five metabolite peaks (1-5) were detected and subsequently analyzed by combined high-performance liquid chromatography-frit-fast atom bombardment-mass spectrometry. The metabolite 4 fraction was found to contain [13C6]-indole-3-acetylaspartic acid, and analysis of metabolite 5 identified [13C6]indole-3-acetyl-?-d-glucose. The other metabolites could not be identified, but alkaline hydrolysis studies and gel permeation chromatography indicated that metabolites 1 and 3 were both amide conjugates with a molecular weight of approximately 600. Studies with radiolabeled indole-3-acetic acid, indole-3-acetylaspartic acid, and indole-3-acetyl-?-d-glucose demonstrated that in immature pericarp indole-3-acetic acid is deactivated primarily via metabolism to indole-3-acetylaspartic acid, which is further converted to metabolites 1, 2, and 3. In mature, pink pericarp discs, indole-3-acetic acid is converted more extensively to its glucosyl conjugate. Conjugation of indole-3-acetic acid to indole-3-acetylaspartic acid appears to be dependent upon protein synthesis because it is inhibited by cycloheximide. In contrast, cycloheximide has little effect on the further conversion of indole-3-acetylaspartic acid to metabolites 1, 2, and 3.

Catala, Carmen; Ostin, Anders; Chamarro, Jesus; Sandberg, Goran; Crozier, Alan

1992-01-01

218

Acetic Acid Bacterial Biota of the Pink Sugar Cane Mealybug, Saccharococcus sacchari, and Its Environs  

PubMed Central

Saccharococcus sacchari is the primary colonizer of the developing “sterile” tissue between the leaf sheath and stem of sugar cane. The honeydew secreted by the mealybugs is acidic (about pH 3) and supports an atypical epiphytic microbiota dominated by acetobacter-like bacteria and acidophilic yeast species. However, Erwinia and Leuconostoc species predominate within the leaf sheath pocket region when the mealybugs die out. The unidentified acetobacters were readily isolated from S. sacchari throughout its life cycle and from other genera of mealybugs on sugar cane and various other plants, both above and below ground. No other insect present on sugar cane was a significant vector of acetic acid bacteria. The major factors restricting microbial diversity within the environs of mealybugs were considered to be yeast activity along with bacterial production of acetic acid, ketogluconic acids, and gamma-pyrones, in association with their lowering of pH. The microbial products may aid in suppressing the attack by the parasitic mold Aspergillus parasiticus on mealybugs but could act as attractants for the predatory fruit fly Cacoxenus perspicax.

Ashbolt, Nicholas J.; Inkerman, Peter A.

1990-01-01

219

Toxicokinetics and Oral Bioavailability of Halogenated Acetic Acids Mixtures in Naive and GSTzeta-Depleted Rats  

SciTech Connect

Pharmacokinetics of halogenated acetic acid (HAA) mixtures in native and GSTzeta depleted rats was investigated. Rats were administered orally or i.v. to Mixture-1 (monobromo- dichloro-, chlorodibromo-, tribromo- acetic acids) or Mixture-2 (bromochloro-, dibromo-, trichloro- bromodichloro- acetic acids) at a dose of 25 ?mol/kg HAA and blood samples collected up to 36 h. GSTzeta depleted rats were also orally dosed with each mixture and euthanized at 0.25, 0.5, 1, 2 and 4 h to determine tissue distribution. In Mixture-1, GSTzeta depletion only affected the pharmacokinetics of DCAA, which increased the elimination t? from 9 min to 1.3 h. After oral administration, DCAA exhibited a complex time-course plasma profile with secondary peaks appearing long after completion of the initial absorption phase. This phenomenon coincided with elevated DCA levels in the lower portion of the GI tract compared to CDBAA and TBAA. For Mixture-2, all di-HAAs were eliminated extremely rapidly from plasma in both na?ve and GSTzeta depleted animals (t? was 4-11 min in na?ve and 11-24 min in GSTzeta depleted rats), t? of BDCAA and TCAA was 3.5 and 12 h in na?ve and 2.3 and 7.5 h in GSTzeta depleted rats. The primary difference in the pharmacokinetics among HAAs when administered as mixture was the total body clearance (Clb) which was reduced compared to after individual administration. These results suggest competitive interactions between tri- and di-HAAs beyond what would be predicted from individual HAA studies. For di-HAAs, the total dose is important as clearance is dose dependent due to competition for GSTzeta. When considering HAAs dosimetry, importance should be placed on both the components of the mixture and prior exposure history to di-HAAs.

Saghir, Shakil A.; Schultz, Irv R.

2005-04-01

220

Kinetics of the • OH-radical initiated reactions of acetic acid and its deuterated isomers  

Microsoft Academic Search

Kinetics of the •OH-initiated reactions of acetic acid and its deuterated isomers have been investigated performing simulation chamber experiments\\u000a at T = 300 ± 2 K. The following rate constant values have been obtained (± 1?, in cm3 molecule?1 s?1): k\\u000a 1(CH3C(O)OH + •OH) = (6.3 ± 0.9) × 10?13, k\\u000a 2(CH3C(O)OD + •OH) = (1.5 ± 0.3) × 10?13,

Emese Szabó; Jérémy Tarmoul; Alexandre Tomas; Christa Fittschen; Sándor Dóbé; Patrice Coddeville

2009-01-01

221

New tetrazole-1-acetic acid esters for enzymatic synthesis of cefazolin  

Microsoft Academic Search

The enzymatic synthesis of cefazolin (CEZ) using esters of tetrazole-1-acetic acid (TzAA esters) with saturated lower alcohols\\u000a is reported. The optimum ratios of acyl-donor:acyl-acceptor in the enzymatic synthesis were determined. It is shown that a\\u000a threefold molar excess of acyl-donor for about 165 min, a conversion rate of about 55% is obtained with these TzAA esters.\\u000a The syntheses were carried

M. Kostadinov; A. Nikolov; N. Tsoneva; N. Petkov

1992-01-01

222

A new CO 2 disposal process via artificial weathering of calcium silicate accelerated by acetic acid  

Microsoft Academic Search

A new disposal process for anthropogenic CO2 via an artificially accelerated weathering reaction is proposed to counteract global warming. The process is essentially composed of the following two steps:(1)CaSiO3+2CH3COOH?Ca2++2CH3COO?+H2O+SiO2(2)Ca2++2CH3COO?+CO2+H2O?CaCO3?+2CH3COOHStep (1) is the extraction of calcium ions by acetic acid from calcium silicate, for example, wollastonite rocks. Step (2) is the deposition of calcium carbonate from the solution of calcium ions

M. Kakizawa; A. Yamasaki; Y. Yanagisawa

2001-01-01

223

Indole-3-Acetic Acid Biosynthesis in the Mutant Maize orange pericarp, a Tryptophan Auxotroph.  

PubMed

The maize mutant orange pericarp is a tryptophan auxotroph, which results from mutation of two unlinked loci of tryptophan synthase B. This mutant was used to test the hypothesis that tryptophan is the precursor to the plant hormone indole-3-acetic acid (IAA). Total IAA in aseptically grown mutant seedlings was 50 times greater than in normal seedlings. In mutant seedlings grown on media containing stable isotopelabeled precursors, IAA was more enriched than was tryptophan. No incorporation of label into IAA from tryptophan could be detected. These results establish that IAA can be produced de novo without tryptophan as an intermediate. PMID:17731524

Wright, A D; Sampson, M B; Neuffer, M G; Michalczuk, L; Slovin, J P; Cohen, J D

1991-11-15

224

Biosynthesis of Indole-3-Acetic Acid by the Pine Ectomycorrhizal Fungus Pisolithus tinctorius  

PubMed Central

Previous work has indicated that anatomical and morphological changes (stunting and dichotomy) in roots of various conifers may be influenced by plant-growth-regulating substances secreted by mycorrhizae. Indole-3-acetic acid (IAA) has been tentatively identified as a major auxin produced by some selected ectomycorrhizae. We report the isolation and detection of IAA as a secondary metabolite from Pisolithus tinctorius by thin-layer chromatography, high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent (monoclonal antibody) assay (ELISA), and unequivocal identification by gas chromatography-mass spectrometry (GC-MS). The thin-layer chromatography methods for auxin isolation described here are novel, with the use of heptane-acetone-glacial acetic acid as the migrating solvent and formaldehyde, H2SO4, and vanadate in detection. The acidic extract of the culture supernatant was methylated with ethereal diazomethane to detect IAA as methyl-3-IAA by HPLC, ELISA, and GC-MS. The quantitative amount of IAA detected ranged from 4 to 5 ?mol liter?1 by HPLC and ELISA. Another unidentified metabolite was detected by GC-MS with a typical indole nucleus (m/z = 130), indicating that it could be an intermediate in auxin metabolism. Plant response (Pseudotsuga menziesii, Douglas fir) was monitored upon inoculation of P. tinctorius and l-tryptophan. There was a consistent increase in plant height and stem diameter as a result of the two treatments, with statistical differences in dry weights of the shoots and roots. Images

Frankenberger, W. T.; Poth, M.

1987-01-01

225

Carriers for abscisic acid and indole-3-acetic acid in primary roots: their regional localisation and thermodynamic driving forces  

Microsoft Academic Search

A carrier for the uptake of abscisic acid (ABA) is present in the tips and elongating zones of primary roots of both leguminous (runner bean, French bean, pea) and non-leguminous (sunflower, maize) seedlings. No ABA carrier was present in more mature root regions. For indole-3-acetic acid both carrier-mediated uptake and a 2,3,5-triiodobenzoate-sensitive efflux component are present in growing and in

M. C. Astle; P. H. Rubery

1983-01-01

226

Observation of SERS of picolinic acid and nicotinic acid using cellulose acetate films doped with Ag fine particles  

NASA Astrophysics Data System (ADS)

Surface enhanced Raman (SER) spectra of picolinic acid and nicotinic acid were observed using cellulose acetate (CA) films doped with Ag fine particles. The spectra obtained match those reported for silver colloids though some differences in SER band intensity were observed. The ease of preparation and handling of the CA film method renders it more useful than the colloid method for the observation of SER spectra.

Imai, Yoshika; Kurokawa, Yoichi; Hara, Masaru; Fukushima, Michiko

1997-10-01

227

The kinetics of process dependent ammonia inhibition of methanogenesis from acetic acid.  

PubMed

Advanced anaerobic digestion processes aimed at improving the methanization of sewage sludge may be potentially impaired by the production of inhibitory compounds (e.g. free ammonia). The result of methanogenic inhibition is relatively high effluent concentrations of acetic acid and other soluble organics, as well as reduced methane yields. An extreme example of such an advanced process is the thermal hydrolytic pretreatment of sludge prior to high solids digestion (THD). Compared to a conventional mesophilic anaerobic digestion process (MAD), THD operates in a state of constant inhibition driven by high free ammonia concentrations, and elevated pH values. As such, previous investigations of the kinetics of methanogenesis from acetic acid under uninhibited conditions do not necessarily apply well to the modeling of extreme processes such as THD. By conducting batch ammonia toxicity assays using biomass from THD and MAD reactors, we compared the response of these communities over a broad range of ammonia inhibition. For both processes, increased inhibitor concentrations resulted in a reduction of biomass growth rate (r(max) = ?(max)?X) and a resulting decrease in the substrate half saturation coefficient (K(S)). These two parameters exhibited a high degree of correlation, suggesting that for a constant transport limited system, the K(S) was mostly a linear function of the growth rate. After correcting for reactor pH and temperature, we found that the THD and MAD biomass were both able to perform methanogenesis from acetate at high free ammonia concentrations (equivalent to 3-5 g/L total ammonia nitrogen), albeit at less than 30% of their respective maximum rates. The reduction in methane production was slightly less pronounced for the THD biomass than for MAD, suggesting that the long term exposure to ammonia had selected for a methanogenic pathway less dependent on those organisms most sensitive to ammonia inhibition (i.e. aceticlastic methanogens). PMID:23062786

Wilson, Christopher Allen; Novak, John; Takacs, Imre; Wett, Bernhard; Murthy, Sudhir

2012-12-01

228

Techno-economic Analysis for the Thermochemical Conversion of Lignocellulosic Biomass to Ethanol via Acetic Acid Synthesis  

SciTech Connect

Biomass is a renewable energy resource that can be converted into liquid fuel suitable for transportation applications. As a widely available biomass form, lignocellulosic biomass can have a major impact on domestic transportation fuel supplies and thus help meet the Energy Independence and Security Act renewable energy goals (U.S. Congress 2007). This study performs a techno-economic analysis of the thermo chemical conversion of biomass to ethanol, through methanol and acetic acid, followed by hydrogenation of acetic acid to ethanol. The conversion of syngas to methanol and methanol to acetic acid are well-proven technologies with high conversions and yields. This study was undertaken to determine if this highly selective route to ethanol could provide an already established economically attractive route to ethanol. The feedstock was assumed to be wood chips at 2000 metric ton/day (dry basis). Two types of gasification technologies were evaluated: an indirectly-heated gasifier and a directly-heated oxygen-blown gasifier. Process models were developed and a cost analysis was performed. The carbon monoxide used for acetic acid synthesis from methanol and the hydrogen used for hydrogenation were assumed to be purchased and not derived from the gasifier. Analysis results show that ethanol selling prices are estimated to be $2.79/gallon and $2.81/gallon for the indirectly-heated gasifier and the directly-heated gasifier systems, respectively (1stQ 2008$, 10% ROI). These costs are above the ethanol market price for during the same time period ($1.50 - $2.50/gal). The co-production of acetic acid greatly improves the process economics as shown in the figure below. Here, 20% of the acetic acid is diverted from ethanol production and assumed to be sold as a co-product at the prevailing market prices ($0.40 - $0.60/lb acetic acid), resulting in competitive ethanol production costs.

Zhu, Yunhua; Jones, Susanne B.

2009-04-01

229

Calcium Magnesium Acetate at Lower-Production Cost: Production of CMA Deicer from Cheese Whey.  

National Technical Information Service (NTIS)

Calcium magnesium acetate (CMA), a mixture of calcium acetate and magnesium acetate, is used as an environmentally benign roadway deicer. The present commercial CMA deicer made from glacial acetic acid and dolomitic lime or limestone is expensive compared...

H. Zhu S. T. Yang W. Qin Y. Huang Y. L. Huang Z. Jin

1999-01-01

230

High temperature stimulates acetic acid accumulation and enhances the growth inhibition and ethanol production by Saccharomyces cerevisiae under fermenting conditions.  

PubMed

Cellular responses of Saccharomyces cerevisiae to high temperatures of up to 42 °C during ethanol fermentation at a high glucose concentration (i.e., 100 g/L) were investigated. Increased temperature correlated with stimulated glucose uptake to produce not only the thermal protectant glycerol but also ethanol and acetic acid. Carbon flux into the tricarboxylic acid (TCA) cycle correlated positively with cultivation temperature. These results indicate that the increased demand for energy (in the form of ATP), most likely caused by multiple stressors, including heat, acetic acid, and ethanol, was matched by both the fermentation and respiration pathways. Notably, acetic acid production was substantially stimulated compared to that of other metabolites during growth at increased temperature. The acetic acid produced in addition to ethanol seemed to subsequently result in adverse effects, leading to increased production of reactive oxygen species. This, in turn, appeared to cause the specific growth rate, and glucose uptake rate reduced leading to a decrease of the specific ethanol production rate far before glucose depletion. These results suggest that adverse effects from heat, acetic acid, ethanol, and oxidative stressors are synergistic, resulting in a decrease of the specific growth rate and ethanol production rate and, hence, are major determinants of cell stability and ethanol fermentation performance of S. cerevisiae at high temperatures. The results are discussed in the context of possible applications. PMID:24706214

Woo, Ji-Min; Yang, Kyung-Mi; Kim, Sae-Um; Blank, Lars M; Park, Jin-Byung

2014-07-01

231

?-(Acetic acid)-di-?-chlorido-bis[tri-phenyl-tellurium(IV)] monohydrate  

PubMed Central

The asymmetric unit of the title compound, C38H34Cl2O2Te2·H2O, contains two independent TeIV cations, each coordinated by three phenyl ligands, two Cl? anions and one acetic acid mol­ecule in a distorted octa­hedral C3Cl2O geometry; the longer Te?Cl distances ranging from 3.2007?(11) to 3.4407?(11)?Å and the longer Te?O distances of 3.067?(3) and 3.113?(3)?Å indicate the weak bridge coordination. The Cl? anion and acetic acid mol­ecule bridge the two independent TeIV cations, forming the dimeric complex mol­ecule, in which the Te?Te separation is 3.7314?(4)?Å. In the crystal, the water molecules of crystallization link the TeIV complex mol­ecules into chains running along the b-axis direction via O—H?O and O—H?Cl hydrogen bonds.

Hu, Feng; Xu, Chao; Shi, Hua-Tian; Chen, Qun; Zhang, Qian-Feng

2013-01-01

232

Azithromycin and erythromycin ameliorate the extent of colonic damage induced by acetic acid in rats  

SciTech Connect

Ulcerative colitis is a common inflammatory bowel disease (IBD) of unknown etiology. Recent studies have revealed the role of some microorganisms in the initiation and perpetuation of IBD. The role of antibiotics in the possible modulation of colon inflammation is still uncertain. In this study, we evaluated the effects of two macrolides, namely azithromycin and erythromycin, at different doses on the extent and severity of ulcerative colitis caused by intracolonic administration of 3% acetic acid in rats. The lesions and the inflammatory response were assessed by histology and measurement of myeloperoxidase (MPO) activity, nitric oxide synthetase (NOS) and tumor necrosis factor alpha (TNF{alpha}) in colonic tissues. Inflammation following acetic acid instillation was characterized by oedema, diffuse inflammatory cell infiltration and necrosis. Increase in MPO, NOS and TNF{alpha} was detected in the colonic tissues. Administration of either azithromycin or erythromycin at different dosage (10, 20 and 40 mg/kg orally, daily for 5 consecutive days) significantly (P < 0.05) reduced the colonic damage, MPO and NOS activities as well as TNF{alpha} level. This reduction was highly significant with azithromycin when given at a dose of 40 mg/kg. It is concluded that azithromycin and erythromycin may have a beneficial therapeutic role in ulcerative colitis.

Mahgoub, Afaf [Department of Pharmacology, College of Medicine, King Saud University, Riyadh 11461 (Saudi Arabia)]. E-mail: afaf_mahgoub@yahoo.com; El-Medany, Azza [Department of Pharmacology, College of Medicine, King Saud University, Riyadh 11461 (Saudi Arabia); Mustafa, Ali [Department of Pharmacology, College of Medicine, King Saud University, Riyadh 11461 (Saudi Arabia); Arafah, Maha [Department of Pathology, College of Medicine, King Saud University, Riyadh 11461 (Saudi Arabia); Moursi, Mahmoud [Central Laboratories, Ministry of Health, Riyadh (Saudi Arabia)

2005-05-15

233

Transgenically enhanced expression of indole-3-acetic Acid confers hypervirulence to plant pathogens.  

PubMed

ABSTRACT Fusarium oxysporum and F. arthrosporioides, pathogenic on Orobanche aegyptiaca, were transformed with two genes of the indole-3-acetamide (IAM) pathway leading to indole-3-acetic acid (IAA) to attempt to enhance virulence. Transgenic F. oxysporum lines containing both the tryptophan-2-monooxyngenase (iaaM) and indole-3-acetamide hydrolase (iaaH) genes produced significantly more IAA than the wild type. IAM accumulated in culture extracts of F. oxysporum containing iaaM alone. F. arthrosporioides containing only iaaM accumulated IAM and an unidentified indole. Some transformants of F. oxysporum expressing only the iaaM gene also produced more IAA than the wild type. Sub-threshold levels (that barely infect Orobanche) of transgenic F. oxysporum expressing both genes and of F. arthrosporioides expressing iaaM were more effective in suppressing the number and size of Orobanche shoots than the wild type on tomato plants grown in soil mixed with Orobanche seed. Stimulating an auxin imbalance enhanced pathogen virulence by affecting the host in a manner similar to low doses of auxin herbicides such as 2,4-dichlorophenoxy acetic acid. PMID:18944254

Cohen, Barry A; Amsellem, Ziva; Maor, Rudy; Sharon, Amir; Gressel, Jonathan

2002-06-01

234

Main and interaction effects of acetic acid, furfural, and p-hydroxybenzoic acid on growth and ethanol productivity of yeasts  

SciTech Connect

The influence of the factors acetic acid, furfural, and p-hydroxybenzoic acid on the ethanol yield (Y{sub EtOH}) of Saccharomyces cerevisiae, bakers` yeast, S. cerevisiae ATCC 96581, and Candida shehatae NJ 23 was investigated using a 2{sup 3}-full factorial design with 3 centerpoints. The results indicated that acetic acid inhibited the fermentation by C. shehatae NJ 23 markedly more than by bakers` yeast, whereas no significant difference in tolerance towards the compounds was detected between the S. cerevisiae strains. Furfural and the lignin derived compound p-hydroxybenzoic acid did not affect any of the yeasts at the cell mass concentration used. The results indicated that the linear model was not adequate to describe the experimental data. Based on the results from the 2{sup 3}-full factorial experiment, an extended experiment was designed based on a central composite design to investigate the influence of the factors on the specific growth rate ({mu}), biomass yield (Y{sub x}), volumetric ethanol productivity (Q{sub EtOH}), and Y{sub EtOH}. Bakers` yeast was chosen in the extended experiment due to its better tolerance towards acetic acid, which makes it a more interesting organism for use in industrial fermentations of lignocellulosic hydrolysates.

Palmqvist, E.; Grage, H.; Meinander, N.Q.; Hahn-Haegerdal, B. [Univ. of Lund (Sweden)

1999-04-05

235

The Partitioning of Acetic, Formic, and Phosphoric Acids Between Liquid Water and Steam  

SciTech Connect

The chemical carryover of impurities and treatment chemicals from the boiler to the steam phase, and ultimately to the low-pressure turbine and condenser, can be quantified based on laboratory experiments preformed over ranges of temperature, pH, and composition. The two major assumptions are that thermodynamic equilibrium is maintained and no deposition, adsorption or decomposition occurs. The most recent results on acetic, formic and phosphoric acids are presented with consideration of the effects of hydrolysis and dimerization reactions. Complications arising from thermal decomposition of the organic acids are discussed. The partitioning constants for these acids and other solutes measured in this program have been incorporated into a simple thermodynamic computer code that calculates the effect of chemical and mechanical carryover on the composition of the condensate formed to varying extents in the water/steam cycle.

Gruszkiewicz, M.S.; Marshall, S.L.; Palmer, D.A.; Simonson, J.M.

1999-06-22

236

Ameyamaea chiangmaiensis gen. nov., sp. nov., an acetic acid bacterium in the alpha-Proteobacteria.  

PubMed

Two isolates, AC04(T) and AC05, were isolated from the flowers of red ginger collected in Chiang Mai, Thailand. In phylogenetic trees based on 16S rRNA gene sequences, the two isolates were included within a lineage comprised of the genera Acidomonas, Gluconacetobacter, Asaia, Kozakia, Swaminathania, Neoasaia, Granulibacter, and Tanticharoenia, and they formed an independent cluster along with the type strain of Tanticharoenia sakaeratensis. The calculated pair-wise sequence similarities of isolate AC04(T) were 97.8-92.5% to the type strains of the type species of the 11 genera of acetic acid bacteria. The DNA base composition was 66.0-66.1 mol % G+C with a range of 0.1 mol %. A single-stranded, labeled DNA from isolate AC04(T) presented levels of DNA-DNA hybridization of 100, 85, 4, and 3% respectively to DNAs from isolates AC04(T) and AC05 and the type strains of Tanticharoenia sakaeratensis and Gluconacetobacter liquefaciens. The two isolates were unique morphologically in polar flagellation and physiologically in intense acetate oxidation to carbon dioxide and water and weak lactate oxidation. The intensity in acetate oxidation almost equaled that of the type strain of Acetobacter aceti. The two isolates had Q-10. Isolate AC04(T) was discriminated from the type strains of the type species of the 11 genera by 16S rRNA gene restriction analysis using restriction endonucleases TaqI and Hin6I. The unique phylogenetic, genetic, morphological, physiological, and biochemical characteristics obtained indicate that the two isolates can be classified into a separate genus, and Ameyamaea chiangmaiensis gen. nov., sp. nov. is proposed. The type strain is isolate AC04(T) (=BCC 15744(T), =NBRC 103196(T)), which has a DNA G+C content of 66.0 mol %. PMID:19809199

Yukphan, Pattaraporn; Malimas, Taweesak; Muramatsu, Yuki; Takahashi, Mai; Kaneyasu, Mika; Potacharoen, Wanchern; Tanasupawat, Somboon; Nakagawa, Yasuyoshi; Hamana, Koei; Tahara, Yasutaka; Suzuki, Ken-ichiro; Tanticharoen, Morakot; Yamada, Yuzo

2009-10-01

237

Influence of heated vegetable oils and ??tocopheryl acetate supplementation on ??tocopherol, fatty acids and lipid peroxidation in chicken muscle  

Microsoft Academic Search

1. Chicks were fed on diets containing fresh, heated or ??tocopheryl acetate?supplemented heated vegetable oils. The effects on ??tocopherol status, and on the fatty acid composition and oxidative stability of thigh and breast muscle were determined.2. Plasma ??tocopherol was significantly correlated with ??tocopherol concentrations in thigh and breast muscle.3. The fatty acid profiles of muscle lipids reflected dietary fatty acid

P. J. A. Sheehy; P. A. Morrissey; A. Flynn

1993-01-01

238

Carbon-isotopic analysis of dissolved acetate  

SciTech Connect

Heating of dried, acetate-containing solids together with oxalic acid dihydrate conveniently releases acetic acid for purification by gas chromatography. For determination of the carbon-isotopic composition of total acetate, the acetate-containing zone of the chromatographic effluent can be routed directly to a combustion furnace coupled to a vacuum system allowing recovery, purification, and packaging of CO{sub 2} for mass-spectrometric analysis. For analysis of methyl carbon, acetic acid can be cryogenically trapped from the chromatographic effluent, then transferred to a tube containing excess NaOH. The tube is evacuated, sealed, and heated to 500{degree}C to produce methane by pyrolysis of sodium acetate. Subsequent combustion of the methane allows determination of the {sup 13}C content at the methyl position in the parent acetate. With typical blanks, the standard deviation of single analyses is less than 0.4{per thousand} for acetate samples larger than 5 {mu}mol. A full treatment of uncertainties is outlined.

Gelwicks, J.T. (Merck and Co., Inc., Rahway, NJ (USA)); Hayes, J.M. (Indiana Univ., Bloomington (USA))

1990-03-01

239

[Effect of acetic acid, furfural and 5-hydroxymethylfurfural on production of 2,3-butanediol by Klebsiella oxytoca].  

PubMed

To get the tolerability and consumption of Klebsiella oxytoca on major inhibitors in lignocelluloses hydrolysate, we studied the effect of acetic acid, furfural and 5-hydroxymethylfurfural on production of 2,3-butanediol by Klebsiella oxytoca. The metabolites of furfural and 5-hydroxymethylfurfural were measured. The results show that when acetic acid, furfural and 5-hydroxymethylfurfural was individually added, tolerance threshold for Klebsiella oxytoca was 30 g/L, 4 g/L and 5 g/L, respectively. Acetic acid was likely used as substrate to produce 2,3-butanediol. The yield of 2,3-butanediol increased when acetic acid concentration was lower than 30 g/L. In the fermentation, more than 70% 5-hydroxymethylfurfural was converted to 2,5-furandimethanol. All furfural and the rest of 5-hydroxymethylfurfural were metabolized by Klebsiella oxytoca. It showed that in the detoxification process of 2,3-butanediol production using lignocelluloses hydrolysate, furfural should be given priority to remove and a certain concentration of acetic acid is not need to removal. PMID:23789276

Wu, Jing; Cheng, Keke; Li, Wenying; Feng, Jie; Zhang, Jian'an

2013-03-01

240

Effect of the temperature of dehydration of zeolite on sorption of acetic acid from organic solvents with water  

SciTech Connect

This paper measures the sorption of acetic acid from carbon tetrachloride, toluene, acetone, and water on NaX zeolite dehydrated in air at the temperatures of 370, 470, and 670 K and on nondehydrated zeolite. It was found that the capacity of the sorbent with respect to acetic acid increases in hydrophobic solvents (CCl/sub 4/ and toluene) with a decrease in the degree of dehydration and decreases in hydrophilic acetone. The capacity of the sorbent, the intensity, rate, and relative sorption of acetic acid from aqueous solutions are almost independent of the degree of dehydration of the zeolite. The efficiency of sorption purification of carboxylic acid from organic solvents is primarily predetermined by the intensity of sorption isotherms obtained.

Akhmadeev, V.Y.; Levitskaya, G.D.; Oshchapovskii, V.V.; Shevchuk, I.A.; Tatomyr, Y.T.

1985-05-20

241

Gluconacetobacter maltaceti sp. nov., a novel vinegar producing acetic acid bacterium.  

PubMed

Comparison of HaeIII- and HpaII-restriction profiles of PCR-amplified 16S-23S rDNA ITS regions of Gluconacetobacter sp. LMG 1529(T) and SKU 1109 with restriction profiles of reference strains of acetic acid bacteria described by Tr?ek and Teuber [34] revealed the same but unique restriction profiles for LMG 1529(T) and SKU 1109. Further analyses of nearly complete 16S rRNA gene sequences, nearly complete 16S-23S rDNA ITS sequences, as well as concatenated partial sequences of the housekeeping genes dnaK, groEL and rpoB, allocated both strains to a single phylogenetic cluster well separated from the other species of the genus Gluconacetobacter. DNA-DNA hybridizations confirmed their novel species identity by 73% DNA-DNA relatedness between both strains, and values below the species level (<70%) between SKU 1109 and the type strains of the closest phylogenetic neighbors. The classification of strains LMG 1529(T) and SKU 1109 into a single novel species was confirmed also by AFLP and (GTG)(5)-PCR DNA fingerprinting data, as well as by phenotypic data. Strains LMG 1529(T) and SKU 1109 can be differentiated from their closely related Gluconacetobacter species, Gluconacetobacter entanii and Gluconacetobacter hansenii, by their ability to form 2-keto-d-gluconic acid from d-glucose, their ability to use d-mannitol, d-gluconate and glycerol as carbon source and form acid from d-fructose, and their ability to grow without acetic acid. The major fatty acid of LMG 1529(T) and SKU 1109 is C(18:1?7c) (60.2-64.8%). The DNA G+C content of LMG 1529(T) and SKU 1109 is 62.5 and 63.3mol% respectively. The name Gluconacetobacter maltaceti sp. nov. is proposed. The type strain is LMG 1529(T) (=NBRC 14815(T)=NCIMB 8752(T)). PMID:23273842

Slapšak, Nina; Cleenwerck, Ilse; De Vos, Paul; Tr?ek, Janja

2013-02-01

242

Definitive identification of indole-3-acetic acid and abscisic acid in shoots of Coleus blumei by gas chromatography-mass spectrometry  

Microsoft Academic Search

Mass spectra provide definitive identification of indole-3-acetic acid and abscisic acid in shoots of Coleus blumei, a species used for studying the hormone control of plant development since the early 1930s.

Clifford E. LaMotte; Xiaoyue Li; William P. Jacobs

1998-01-01

243

Nickel, copper and zinc complexes of (2-methoxycarbonylmethylimino-5-methyl-thiazol-3-yl)-acetic acid  

Microsoft Academic Search

An ester of an imine containing dicarboxylic acid (2-methoxycarbonylmethylimino-5-methyl-thiazol-3-yl)-acetic acid methyl ester was prepared by the reaction of methylbromoacetate with 5-methyl-thiazol-2-ylamine. Base hydrolysis of this ester with sodium hydroxide gives the corresponding disodium salt of the diacid. The disodium salt of (2-methoxycarbonylmethylimino-5-methyl-thiazol-3-yl)-acetic acid (Na2L) forms a mononuclear hexacoordinated complex [Ni(L)(H2O)3]2H2O] with nickel, whereas it forms a pentacoordinated coordination polymer with

W. Marjit Singh; Jubaraj B. Baruah

2008-01-01

244

Microarray-based transcriptome of Listeria monocytogenes adapted to sublethal concentrations of acetic acid, lactic acid, and hydrochloric acid.  

PubMed

Listeria monocytogenes , an important foodborne pathogen, commonly encounters organic acids in food-related environments. The transcriptome of L. monocytogenes L502 was analyzed after adaptation to pH 5 in the presence of acetic acid, lactic acid, or hydrochloric acid (HCl) at 25 °C, representing a condition encountered in mildly acidic ready-to-eat food kept at room temperature. The acid-treated cells were compared with a reference culture with a pH of 6.7 at the time of RNA harvesting. The number of genes and magnitude of transcriptional responses were higher for the organic acids than for HCl. Protein coding genes described for low pH stress, energy transport and metabolism, virulence determinates, and acid tolerance response were commonly regulated in the 3 acid-stressed cultures. Interestingly, the transcriptional levels of histidine and cell wall biosynthetic operons were upregulated, indicating possible universal response against low pH stress in L. monocytogenes. The opuCABCD operon, coding proteins for compatible solutes transport, and the transcriptional regulator sigL were significantly induced in the organic acids, strongly suggesting key roles during organic acid stress. The present study revealed the complex transcriptional responses of L. monocytogenes towards food-related acidulants and opens the roadmap for more specific and in-depth future studies. PMID:22913877

Tessema, Girum Tadesse; Møretrø, Trond; Snipen, Lars; Heir, Even; Holck, Askild; Naterstad, Kristine; Axelsson, Lars

2012-09-01

245

Kozakia baliensis gen. nov., sp. nov., a novel acetic acid bacterium in the alpha-proteobacteria.  

PubMed

Four bacterial strains were isolated from palm brown sugar and ragi collected in Bali and Yogyakarta, Indonesia, by an enrichment culture approach for acetic acid bacteria. Phylogenetic analysis based on 16S rRNA gene sequences showed that the four isolates constituted a cluster separate from the genera Acetobacter, Gluconobacter, Acidomonas, Gluconacetobacter and Asaia with a high bootstrap value in a phylogenetic tree. The isolates had high values of DNA-DNA similarity (78-100%) between one another and low values of the similarity (7-25%) to the type strains of Acetobacter aceti, Gluconobacter oxydans, Gluconacetobacter liquefaciens and Asaia bogorensis. The DNA base composition of the isolates ranged from 56.8 to 57.2 mol% G+C with a range of 0-4 mol%. The major quinone was Q-10. The isolates oxidized acetate and lactate to carbon dioxide and water, but the activity was weak, as with strains of Asaia bogorensis. The isolates differed from Asaia bogorensis strains in phenotypic characteristics. The name Kozakia baliensis gen. nov., sp. nov., is proposed for the four isolates. Strain Yo-3T (= NRIC 0488T = JCM 11301T = IFO 16664T = DSM 14400T) was isolated from palm brown sugar collected in Bali, Indonesia, and was designated as the type strain. PMID:12054243

Lisdiyanti, Puspita; Kawasaki, Hiroko; Widyastuti, Yantyati; Saono, Susono; Seki, Tatsuji; Yamada, Yuzo; Uchimura, Tai; Komagata, Kazuo

2002-05-01

246

Amonia gas: an improved reagent for chemical ionization mass spectrometry of bile acid methyl ester acetates  

SciTech Connect

The ammonia chemical ionization mass spectra of 28 methyl ester acetate derivatives of bile acids and related compounds have been determined by gas-liquid chromatography-mass spectrometry. Advantages of ammonia ionization over the previously studied isobutane ionization include a 130 to 270% enhancement in the sensitivity of base peak monitoring, and direct determination of molecular weight from the base peak (M + NH/sub 4//sup +/) in the mass spectrum of any of the derivatives. Minor ions in the ammonia spectra also allow selective detection of 3-keto compounds and can indicate unsaturation or double bond conjugation in the molecule. The significance of these studies for the detection and quantitation of bile acids is discussed. 2 tables.

DeMark, B.R.; Klein, P.D.

1981-01-01

247

An intercomparison of measurement systems for vapor and particulate phase concentrations of formic and acetic acids  

NASA Technical Reports Server (NTRS)

During June 1986, eight systems for measuring vapor phase and four for measuring particulate phase concentrations of formic acid (HCOOH) and acetic acid (CH3COOH) were intercompared in central Virginia. HCOOH and CH3COOH vapors were sampled by condensate, mist, Chromosorb 103 GC resin, NaOH-coated annular denuders, NaOH-impregnated quartz filters, K2CO3 and NaCO3-impregnated cellulose filters, and Nylasorb membranes. Atmospheric aerosol was collected on Teflon and Nuclepore filters using both hi-vol and lo-vol systems to measure particulate phase concentrations. Performances of the mist chamber and K2CO3-impregnated filter techniques were evaluated using zero air and ambient air spiked with HCOOH(g) and CH3COOH(g), and formaldehyde from permeation sources. The advantages and drawbacks of these methods are reported and discussed.

Keene, William C.; Talbot, Robert W.; Andreae, Meinrat O.; Beecher, Kristene; Berresheim, Harold

1989-01-01

248

Biorefining of wheat straw using an acetic and formic acid based organosolv fractionation process.  

PubMed

To assess the potential of acetic and formic acid organosolv fractionation of wheat straw as basis of an integral biorefinery concept, detailed knowledge on yield, composition and purity of the obtained streams is needed. Therefore, the process was performed, all fractions extensively characterized and the mass balance studied. Cellulose pulp yield was 48% of straw dry matter, while it was 21% and 27% for the lignin and hemicellulose-rich fractions. Composition analysis showed that 67% of wheat straw xylan and 96% of lignin were solubilized during the process, resulting in cellulose pulp of 63% purity, containing 93% of wheat straw cellulose. The isolated lignin fraction contained 84% of initial lignin and had a purity of 78%. A good part of wheat straw xylan (58%) ended up in the hemicellulose-rich fraction, half of it as monomeric xylose, together with proteins (44%), minerals (69%) and noticeable amounts of acids used during processing. PMID:24508905

Snelders, Jeroen; Dornez, Emmie; Benjelloun-Mlayah, Bouchra; Huijgen, Wouter J J; de Wild, Paul J; Gosselink, Richard J A; Gerritsma, Jort; Courtin, Christophe M

2014-03-01

249

Rapid identification of acetic acid bacteria using MALDI-TOF mass spectrometry fingerprinting.  

PubMed

Acetic acid bacteria (AAB) are widespread microorganisms characterized by their ability to transform alcohols and sugar-alcohols into their corresponding organic acids. The suitability of matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF MS) for the identification of cultured AAB involved in the industrial production of vinegar was evaluated on 64 reference strains from the genera Acetobacter, Gluconacetobacter and Gluconobacter. Analysis of MS spectra obtained from single colonies of these strains confirmed their basic classification based on comparative 16S rRNA gene sequence analysis. MALDI-TOF analyses of isolates from vinegar cross-checked by comparative sequence analysis of 16S rRNA gene fragments allowed AAB to be identified, and it was possible to differentiate them from mixed cultures and non-AAB. The results showed that MALDI-TOF MS analysis was a rapid and reliable method for the clustering and identification of AAB species. PMID:23182036

Andrés-Barrao, Cristina; Benagli, Cinzia; Chappuis, Malou; Ortega Pérez, Ruben; Tonolla, Mauro; Barja, François

2013-03-01

250

Liquid-liquid equilibria of the ternary system water + acetic acid + 1-hexanol  

SciTech Connect

The recovery of organic acids from dilute solutions resulting from fermentation processes is important and many solvents have been tried to improve such recovery. Liquid-liquid equilibria for the ternary system water + acetic acid + 1-hexanol were measured over a temperature range of (288 to 323) K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models and between each of the main groups of H{sub 2}O, CH{sub 2} (paraffinic CH{sub 2}), OH, and COOH for the UNIFAC model as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the three models. The NRTL equation was the most accurate model in correlating the overall equilibrium compositions of the studied system. The UNIQUAC and UNIFAC models satisfactorily predicted the equilibrium compositions.

Fahim, M.A. [Kuwait Univ., Safat (Kuwait). Dept. of Chemical Engineering] [Kuwait Univ., Safat (Kuwait). Dept. of Chemical Engineering; Al-Muhtaseb, S.A.; Al-Nashef, I.M. [U.A.E. Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering] [U.A.E. Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

1997-01-01

251

A novel kinetic model for polysaccharide dissolution during atmospheric acetic acid pretreatment of sugarcane bagasse.  

PubMed

Acetic acid (AcH) pretreatment of sugarcane bagasse with the catalysis of sulfuric acid (SA) could greatly enhance the enzymatic digestibility of cellulose. However, polysaccharide dissolution happened inevitably during the pretreatment. It was found that the simplest model, which assumes that the total polysaccharides were reactive to be dissolved, could not well describe the kinetic behavior of polysaccharide dissolution. A novel pseudo-homogenous kinetic model was thus developed by introducing a parameter termed as "potential dissolution degree" (?(d)) based on the multilayered structure of cell wall. It was found that solid xylan and glucan dissolutions were a first-order reaction with respect to the dissolvable fraction. Due to the delignification action of AcH, polysaccharide dissolutions were enhanced in AcH media compared with those in aqueous system. Acetylizations of cellulose and sugars were also observed, and AcH concentration showed a significant influence on the degree of acetylization. PMID:24215769

Zhao, Xuebing; Morikawa, Yuichi; Qi, Feng; Zeng, Jing; Liu, Dehua

2014-01-01

252

Piperidine Acetic Acid Based ?-Secretase Modulators Directly Bind to Presenilin-1  

PubMed Central

A?42 is believed to play a causative role in Alzheimer’s disease (AD) pathogenesis. ?-Secretase modulators (GSMs) are actively being pursued as potential AD therapeutics because they selectively alter the cleavage site of the amyloid precursor protein (APP) to reduce the formation of A?42. However, the binding partner of acid based GSMs was unresolved until now. We have developed clickable photoaffinity probes based on piperidine acetic acid GSM-1 and identified PS1 as the target within the ?-secretase complex. Furthermore, we provide evidence that allosteric interaction of GSMs with PS1 results in a conformational change in the active site of the ?-secretase complex leading to the observed modulation of ?-secretase activity.

2011-01-01

253

[Nomegestrol acetate: clinical pharmacology].  

PubMed

Progestogens are used in clinical practice in some conditions. Their effects depend on their chemical structure, pharmacokinetics, pharmacodynamics, with important differences among various progestogens. Generally, progestins are classified according to their parent molecule, of which often they keep some features. Derivatives of 19-nor-progesterone are characterized by high selectivity of action on progestin receptor. In particular, nomegestrol acetate (NomAc) shows an important progestational potency, neutral gluco-lipid profile, and antigonadotropic activity. It is used for treating menstrual cycle disorders and for hormone replacement therapy in menopause in association with an estrogen. In future, thanks to its antigonadotropic activity, NomAc will be used in estroprogestin combinations in fertile women, thus taking advantage of its tolerability profile and obtaining numerous non-contraceptive benefits as well. PMID:19749678

Lello, S

2009-10-01

254

Biomonitoring of 2-(2-alkoxyethoxy)ethanols by analysing urinary 2-(2-alkoxyethoxy)acetic acids.  

PubMed

2-Methoxyacetic and 2-ethoxyacetic acids are well known toxic metabolites of 2-alkoxyethanols. The use of 2-alkoxyethanols is now restricted, and the regulations have forced manufacturers to find substitutive solvents, 2-(2-alkoxyethoxy)ethanols. 2-(2-Alkoxyethoxy)ethanols resemble 2-alkoxyethanols, and their most hazardous similarity is their ability to metabolize to the 2-(2-alkoxyethoxy)acetic acids. In the present study, floor lacquerers' (n = 22) inhalation and total exposure to 2-(2-alkoxy)ethoxyethanols was measured. The measurements of inhalation exposure were done with charcoal tubes, and total exposure was biomonitored by urinalysis of 2-(2-alkoxyethoxy)acetic acids. The 8h inhalation exposures of floor lacquerers to 2-(2-methoxyethoxy)ethanol (DEGME), 2-(2-ethoxyethoxy)ethanol (DEGEE) and 2-(2-butoxyethoxy)ethanol (DEGBE) were in average 0.23 +/- 0.07 ppm (average+/-S.D., n = 3), 0.08 +/- 0.07 ppm (n = 16), and 0.05 +/- 0.03 ppm (n = 16), respectively. The excretions of 2-(2-methoxyethoxy)acetic acid (MEAA), 2-(2-ethoxyethoxy)acetic acid (EEAA) and 2-(2-butoxyethoxy)acetic acid (BEAA) were in average 4.9 +/- 4.3 mmol/mol creatinine, 9.3 +/- 8.0 mmol/mol creatinine and 9.2 +/- 7.4 mmol/mol creatinine, respectively. A linear relationship was found between the urinary 2-(2-alkoxyethoxy)acetic acid concentrations and the preceding 8-h occupational exposure to 2-(2-alkoxyethoxy)ethanol. PMID:15705492

Laitinen, J; Pulkkinen, J

2005-03-28

255

Iron dissolution of dust source materials during simulated acidic processing: the effect of sulfuric, acetic, and oxalic acids.  

PubMed

Atmospheric organic acids potentially display different capacities in iron (Fe) mobilization from atmospheric dust compared with inorganic acids, but few measurements have been made on this comparison. We report here a laboratory investigation of Fe mobilization of coal fly ash, a representative Fe-containing anthropogenic aerosol, and Arizona test dust, a reference source material for mineral dust, in pH 2 sulfuric acid, acetic acid, and oxalic acid, respectively. The effects of pH and solar radiation on Fe dissolution have also been explored. The relative capacities of these three acids in Fe dissolution are in the order of oxalic acid > sulfuric acid > acetic acid. Oxalate forms mononuclear bidentate ligand with surface Fe and promotes Fe dissolution to the greatest extent. Photolysis of Fe-oxalate complexes further enhances Fe dissolution with the concomitant degradation of oxalate. These results suggest that ligand-promoted dissolution of Fe may play a more significant role in mobilizing Fe from atmospheric dust compared with proton-assisted processing. The role of atmospheric organic acids should be taken into account in global-biogeochemical modeling to better access dissolved atmospheric Fe deposition flux at the ocean surface. PMID:23883276

Chen, Haihan; Grassian, Vicki H

2013-09-17

256

Engineering efficient xylose metabolism into an acetic acid-tolerant Zymomonas mobilis strain by introducing adaptation-induced mutations.  

PubMed

The impact of the two adaptation-induced mutations in an improved xylose-fermenting Zymomonas mobilis strain was investigated. The chromosomal mutation at the xylose reductase gene was critical to xylose metabolism by reducing xylitol formation. Together with the plasmid-borne mutation impacting xylose isomerase activity, these two mutations accounted for 80 % of the improvement achieved by adaptation. To generate a strain fermenting xylose in the presence of high acetic acid concentrations, we transferred the two mutations to an acetic acid-tolerant strain. The resulting strain fermented glucose + xylose (each at 5 % w/v) with 1 % (w/v) acetic acid at pH 5.8 to completion with an ethanol yield of 93.4 %, outperforming other reported strains. This work demonstrated the power of applying molecular understanding in strain improvement. PMID:22669340

Agrawal, Manoj; Wang, Yun; Chen, Rachel Ruizhen

2012-10-01

257

Metal-organic coordination architectures of azole heterocycle ligands bearing acetic acid groups: Synthesis, structure and magnetic properties  

NASA Astrophysics Data System (ADS)

Four new coordination complexes with azole heterocycle ligands bearing acetic acid groups, [Co( L1) 2] n ( 1) , [Cu L1N 3] n ( 2), [Cu( L2) 2·0.5C 2H 5OH·H 2O] n ( 3) and [Co( L2) 2] n ( 4) (here, H L1=1H-imidazole-1-yl-acetic acid, H L2=1H-benzimidazole-1-yl-acetic acid) have been synthesized and structurally characterized. Single-crystal structure analysis shows that 3 and 4 are 2D complexes with 4 4-sql topologies, while another 2D complex 1 has a (4 3) 2(4 6)-kgd topology. And 2 is a 3D complex composed dinuclear ?1,1-bridging azido Cu II entities with distorted rutile topology. The magnetic properties of 1 and 2 have been studied.

Hu, Bo-Wen; Zhao, Jiong-Peng; Yang, Qian; Hu, Tong-Liang; Du, Wen-Ping; Bu, Xian-He

2009-10-01

258

Native lignin structure of Miscanthus x giganteus and its changes during acetic and formic acid fractionation.  

PubMed

Milled wood lignin (MWL) and acetic and formic acid lignin (AL and FL) from Miscanthus x giganteus bark were produced, respectively, before and after organosolv fractionations under optimal conditions, in terms of organic and hydrochloric acid concentrations, liquid/wood ratio, and reaction time. In order to study the M. x giganteus native lignin structure and its modifications during the fractionation process, the lignins were studied by two-dimensional heteronuclear single quantum coherence (2D-(HSQC)), (13)C- and (31)P nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR), size-exclusion chromatography (SEC) both before and after thioacidolysis, and elemental analysis. In addition, chemical composition analysis was performed on ash, Klason lignin, and carbohydrate content. The analyses demonstrated that M. x giganteus native lignin (MWL) is highly acylated at the C(gamma) of the lignin side chain (46%), possibly with p-coumarate and/or acetate groups. This is newsworthy since several earlier studies showed that acylation at the gamma-carbon commonly occurs in C(3) and CAM grasses, whereas M. x giganteus is a C(4) grass. Furthermore, M. x giganteus showed a low S/G ratio (0.7) and a predominance of beta-O-4' linkages (up to 93% of all linkages). AL and FL lose part of these linkages during organosolv fractionation (up to 21 and 32%, respectively). The p-coumarate groups resist fractionation processes and are still present in high quantities in AL and FL. During the fractionation process, lignin is acetylated (acetic acid process) and condensed, with the G units condensing more than S units. M. x giganteus MWL contains a high content of carbohydrates (22.8%), suggesting that it is a lignin-carbohydrate complex (LCC). AL and FL showed low carbohydrate contents because of the breaking down of the LCC structures. AL and FL have high molecular weights and low polydispersities, and are high in phenolic content, qualities that make these suitable for different applications. These results suggest that refinement of M. x giganteus via organosolv processes could potentially turn this grass into a valuable source of both fiber and lignin. PMID:19552425

Villaverde, Juan José; Li, Jiebing; Ek, Monica; Ligero, Pablo; de Vega, Alberto

2009-07-22

259

Suppressing glucose uptake and acetic acid production increases membrane protein overexpression in Escherichia coli  

PubMed Central

Background The production of integral membrane spanning proteins (IMP's) constitutes a bottleneck in pharmaceutical development. It was long considered that the state-of-the-art was to produce the proteins as inclusion bodies using a powerful induction system. However, the quality of the protein was compromised and the production of a soluble protein that is incorporated into the membrane from which it is extracted is now considered to be a better method. Earlier research has indicated that a slower rate of protein synthesis might overcome the tendency to form inclusion bodies. We here suggest the use of a set of E. coli mutants characterized by a slower rate of growth and protein synthesis as a tool for increasing the amount of soluble protein in high- throughput protein production processes. Results A set of five IMP's was chosen which were expressed in three mutants and the corresponding WT cell (control). The mutations led to three different substrate uptake rates, two of which were considerably slower than that of the wild type. Using the mutants, we were able to express three out of the five membrane proteins. Most successful was the mutant growing at 50% of the wild type growth rate. A further effect of a low growth rate is a low acetic acid formation, and we believe that this is a possible reason for the better production. This hypothesis was further supported by expression from the BL21(DE3) strain, using the same plasmid. This strain grows at a high growth rate but nevertheless yields only small amounts of acetic acid. This strain was also able to express three out of the five IMP's, although at lower quantities. Conclusions The use of mutants that reduce the specific substrate uptake rate seems to be a versatile tool for overcoming some of the difficulties in the production of integral membrane spanning proteins. A set of strains with mutations in the glucose uptake system and with a lower acetic acid formation were able to produce three out of five membrane proteins that it was not possible to produce with the corresponding wild type.

2011-01-01

260

Thermogravimetric analysis of the relationship among calcium magnesium acetate, calcium acetate and magnesium acetate  

Microsoft Academic Search

Thermal decomposition characteristic of calcium magnesium acetate (CMA), calcium acetate (CA) and magnesium acetate (MA) are investigated through thermogravimetric (TG) analysis at the heating rates of 5Kmin?1, 7.5Kmin?1, 10Kmin?1 and 15Kmin?1. After dehydration, the evaporation of carboxylic radical and carbon dioxide of CMA and CA exist in two separate segments, but for MA, this occurs together in just one segment

Shengli Niu; Kuihua Han; Chunmei Lu; Rongyue Sun

2010-01-01

261

Hydrogen production from steam reforming of acetic acid over Cu-Zn supported calcium aluminate.  

PubMed

Hydrogen can be produced by catalytic steam reforming (CSR) of biomass-derived oil. Typically bio oil contains 12-14% acetic acid; therefore, this acid was chosen as model compound for reforming of biooil with the help of a Cu-Zn/Ca-Al catalyst for high yield of H(2) with low CH(4) and CO content. Calcium aluminate support was prepared by solid-solid reaction at 1350°C. X-ray diffraction indicates 12CaO·7Al(2)O(3) as major, CaA(l4)O(7) and Ca(5)A(l6)O(14) as minor phases. Cu and Zn were loaded onto the support by wet-impregnation at 10 and 1wt.%, respectively. The catalysts were characterized by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy TEM and the surface area for both support and Cu-Zn were 10.5 and 5.8m(2)/g, respectively. CSR was carried out in a tubular fixed bed reactor (I.D.=19mm) at temperatures between 600 and 800°C with 3-g loadings and (H(2)O/acetic acid) wt. ratio of 9:1. Significantly high (80%) yield of hydrogen was obtained over Cu-Zn/Ca-Al catalyst, as incorporation of Zn enhanced the H(2) yield by reducing deactivation of the catalyst. The coke formation on the support (Ca-12/Al-7) surface was negligible due to the presence of excess oxygen in the 12CaO·7Al(2)O(3) phase. PMID:22944490

Mohanty, Pravakar; Patel, Madhumita; Pant, Kamal K

2012-11-01

262

Preyssler-Structured Tungstophosphoric Acid Catalyst on Functionalized Silica for Esterification of n Butanol with Acetic Acid  

Microsoft Academic Search

The Preyssler-structured tungstophosphoric acid catalyst supported on functionalized silica (Preyssler\\/F-silica) was prepared\\u000a by means of grafting technique with amine group as coupling media, and its catalytic behavior was investigated in the esterification\\u000a of n-butanol with acetic acid. The catalyst was characterized by infra-red spectroscopy, UV–Vis spectroscopy, Hammett indicator\\u000a and N2 adsorption techniques. Catalysts prepared directly by impregnating Preyssler acid on

Shanshan Wu; Weihong Zhang; Jun Wang; Xiaoqian Ren

2008-01-01

263

Study of polydimethylsiloxane/aromatic polyamide laminated membranes for separation of acetic acid/water mixtures by pervaporation process  

SciTech Connect

Separation of acetic acid/water mixtures by pervaporation was attempted over a range of compositions using polydimethylsiloxane (PDMS), aromatic polyamide (PA), and laminated polydimethylsiloxane-aromatic polyamide membranes. PDMS membranes are hydrophobic and acetic acid selective, whereas PA membranes are hydrophilic and water selective. When PDMS and PA membranes were laminated, with PDMS on the top side and in contact with the feed, water selectivity of the bottom PA membrane was intensified. On the other hand, when the PA membrane was on the top side and in contact with the feed, the selectivity was lowered. 10 refs., 4 figs.

Deng, S.; Sourirajan, S.; Matsuura, T. (Univ. of Ottawa (Canada))

1994-06-01

264

Isotopic composition of Murchison organic compounds: Intramolecular carbon isotope fractionation of acetic acid. Simulation studies of cosmochemical organic syntheses  

NASA Technical Reports Server (NTRS)

Recently, in our laboratories, samples of Murchison acetic acid were decarboxylated successfully and the carbon isotopic composition was measured for the methane released by this procedure. These analyses showed significant differences in C-13/C-12 ratios for the methyl and carboxyl carbons of the acetic acid molecule, strongly suggesting that more than one carbon source may be involved in the synthesis of the Murchison organic compounds. On the basis of this finding, laboratory model systems simulating cosmochemical synthesis are being studied, especially those processes capable of involving two or more starting carbon sources.

Yuen, G. U.; Cronin, J. R.; Blair, N. E.; Desmarais, D. J.; Chang, S.

1991-01-01

265

Okadaic acid: an additional non-phorbol-12-tetradecanoate-13-acetate-type tumor promoter.  

PubMed Central

Okadaic acid is a polyether compound of a C38 fatty acid, isolated from a black sponge, Halichondria okadai. Previous studies showed that okadaic acid is a skin irritant and induces ornithine decarboxylase (OrnDCase; 3-hydroxyl-L-glutamate 1-carboxy-lyase, EC 4.1.1.17) in mouse skin 4 hr after its application to the skin. This induction was strongly inhibited by pretreatment of the skin with 13-cis-retinoic acid. A two-stage carcinogenesis experiment in mouse skin initiated by a single application of 100 micrograms of 7,12-dimethylbenz[a]anthracene (DMBA) and followed by application of 10 micrograms of okadaic acid twice a week revealed that okadaic acid is a potent additional tumor promoter: tumors developed in 93% of the mice treated with DMBA and okadaic acid by week 16. In contrast, tumors were found in only one mouse each in the groups treated with DMBA alone or okadaic acid alone. An average of 2.6 tumors per mouse was found in week 30 in the group treated with DMBA and okadaic acid. Unlike phorbol 12-tetradecanoate 13-acetate (TPA), teleocidin, and aplysiatoxin, okadaic acid did not inhibit the specific binding of [3H]TPA to a mouse skin particulate fraction when added up to 100 microM or activate calcium-activated, phospholipid-dependent protein kinase (protein kinase C) in vitro when added up to 1.2 microM. Therefore, the actions of okadaic acid and phorbol ester may be mediated in different ways. These results show that okadaic acid is a non-TPA-type tumor promoter in mouse skin carcinogenesis.

Suganuma, M; Fujiki, H; Suguri, H; Yoshizawa, S; Hirota, M; Nakayasu, M; Ojika, M; Wakamatsu, K; Yamada, K; Sugimura, T

1988-01-01

266

Stabilized Calcium Acetate Oil Dispersions.  

National Technical Information Service (NTIS)

A lubricating composition is imparted with improved load-carrying ability and anti-wear properties by incorporation of calcium acetate. The composition consists of a base lubricant, 0.1 to 50 percent by weight calcium acetate and 0.01 to 20 percent by wei...

R. H. Davis

1965-01-01

267

[Formulation of calcium acetate tablets].  

PubMed

The results of the testing of calcium acetate tablets, produced by direct compression and by wet granulation (Ph. Jug. IV) are presented. Tablet hardness, friability and disintegration were determined. The best properties were observed in the tablets produced with maize starch. This procedure is fast and simple, and compound tablets of calcium acetate fulfill the current requirements for this type of preparation. PMID:11521467

Obrenovic, D; Gazikalovic, E; Ognjanovic, J; Nidzovic Z, Z

2000-01-01

268

One-component thioxanthone acetic acid derivative photoinitiator for free radical polymerization.  

PubMed

Acetic acid-based thioxanthone (TXCH2 COOH) was synthesized and characterized and used as a photoinitiator for free radical photopolymerization of methyl methacrylate (MMA) in the absence and presence of a tertiary amine (MDEA) in different solvents. Different absorption properties were observed depending on the solvent. Fluorescence and phosphorescence experiments were also carried out successfully. The fluorescence quantum yield was found to be 0.09 and the phosphorescence lifetime was calculated as 138 ms at 77 K. The photoinitiator undergoes efficient intersystem crossing into the triplet state and the lowest triplet state possesses ?-?* configuration. Laser flash photolysis experiments show that transient absorption of TXCH2 COOH is similar to the parent thioxanthone and the triplet lifetime was calculated as 2.3 ?s at 630 nm. PMID:24372104

Esen, Duygu S; Temel, Gokhan; Balta, Demet K; Allonas, Xavier; Arsu, Nergis

2014-01-01

269

Acetic Acid Bacteria Genomes Reveal Functional Traits for Adaptation to Life in Insect Guts  

PubMed Central

Acetic acid bacteria (AAB) live in sugar rich environments, including food matrices, plant tissues, and the gut of sugar-feeding insects. By comparing the newly sequenced genomes of Asaia platycodi and Saccharibacter sp., symbionts of Anopheles stephensi and Apis mellifera, respectively, with those of 14 other AAB, we provide a genomic view of the evolutionary pattern of this bacterial group and clues on traits that explain the success of AAB as insect symbionts. A specific pre-adaptive trait, cytochrome bo3 ubiquinol oxidase, appears ancestral in AAB and shows a phylogeny that is congruent with that of the genomes. The functional properties of this terminal oxidase might have allowed AAB to adapt to the diverse oxygen levels of arthropod guts.

Chouaia, Bessem; Gaiarsa, Stefano; Crotti, Elena; Comandatore, Francesco; Degli Esposti, Mauro; Ricci, Irene; Alma, Alberto; Favia, Guido; Bandi, Claudio; Daffonchio, Daniele

2014-01-01

270

Photoinduced excited state proton rearrangement of 6-hydroxyquinoline along a hydrogen-bonded acetic acid wire  

NASA Astrophysics Data System (ADS)

6-Hydroxyquinoline (6-HQ) in benzene emits normal fluorescence around 357 nm. In the presence of acetic acid (HOAc), it exhibits two more bands at ˜419 nm and a large Stokes shifted one at ˜583 nm with decreased intensity of the normal fluorescence. It appears to form (1:1) and (1:2) complexes-(1:2) 6-HQ/HOAc undergoes an excited state proton rearrangement ( via HOAc wire) resulting in keto tautomer (emitting at ˜583 nm). This appears to be in line with recent findings where ammonia wires facilitate proton/hydrogen translocation (Science, 302, 1736, 2003). However, (1:1) 6-HQ/HOAc exhibits intermediate emission (˜419 nm) presumably due to ESIPT.

Mehata, Mohan Singh

2007-03-01

271

Utilization of Vinegar for Isolation of Cellulose Producing Acetic Acid Bacteria  

NASA Astrophysics Data System (ADS)

Wastes of traditionally fermented Turkish vinegar were used in the isolation of cellulose producing acetic acid bacteria. Waste material was pre-enriched in Hestrin-Schramm medium and microorganisms were isolated by plating dilution series on HS agar plates The isolated strains were subjected to elaborate biochemical and physiological tests for identification. Test results were compared to those of reference strains Gluconacetobacter xylinus DSM 46604, Gluconacetobacter hansenii DSM 5602 and Gluconacetobacter liquefaciens DSM 5603. Seventeen strains, out of which only three were found to secrete the exopolysaccharide cellulose. The highest cellulose yield was recorded as 0.263+/-0.02 g cellulose L-1 for the strain AS14 which resembled Gluconacetobacter hansenii in terms of biochemical tests.

Aydin, Y. Andelib; Aksoy, Nuran Deveci

2010-06-01

272

Ultrafine cellulose fibers produced by Asaia bogorensis, an acetic acid bacterium.  

PubMed

The ability to synthesize cellulose by Asaia bogorensis, a member of the acetic acid bacteria, was studied in two substrains, AJ and JCM. Although both strains have identical 16S rDNA sequence, only the AJ strain formed a solid pellicle at the air-liquid interface in static culture medium, and we analyzed this pellicle using a variety of techniques. In the presence of cellulase, glucose and cellobiose were released from the pellicle suggesting that it is made of cellulose. Field emission electron microscopy allowed the visualization of a 3D knitted structure with ultrafine microfibrils (approximately 5-20 nm in width) in cellulose from A. bogorensis compared with the 40-100 nm wide microfibrils observed in cellulose isolated from Gluconacetobacter xylinus, suggesting differences in the mechanism of cellulose biosynthesis or organization of cellulose synthesizing sites in these two related bacterial species. Identifying these differences will lead to a better understanding of cellulose biosynthesis in bacteria. PMID:21650167

Kumagai, Akio; Mizuno, Masahiro; Kato, Naoto; Nozaki, Kouichi; Togawa, Eiji; Yamanaka, Shigeru; Okuda, Kazuo; Saxena, Inder M; Amano, Yoshihiko

2011-07-11

273

[Effect of detergents on the hydroxylation of indolyl-3-acetic acid by an Aspergillus niger culture].  

PubMed

A possibility to increase the hydroxylating activity of Aspergillus niger IBFM F-212 under the action of detergents was studied during transformation of indolyl-3-acetic acid (IAA). The following non-ionogenic surface-active compounds were mainly used: Tweens, Spans, polyethyleneglycol (PEG-400). The effect of the detergents was studied at the stages of growth, transformation and preincubation. At the stage of growth, the best effect was produced by Tween-80. At the stages of transformation and preincubation, the hydroxylating activity increased 1.5 times under the action of a number of Spans and PEG-400. No total positive effect of the detergents on the enzyme activity was found at the stages of growth and transformation. The results suggest that the cellular permeability changes under the action of detergents and the hydroxylating activity of the culture increases as the result. PMID:7412617

Baklashova, T G; Koshcheenko, K A

1980-01-01

274

Liquid-liquid equilibria of the ternary system water + acetic acid + 2-methyl-2-butanol  

SciTech Connect

Liquid-liquid equilibria for the ternary system water + acetic acid + 2-methyl-2-butanol were measured over a temperature range of (288 to 323) K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models and between each of the main groups of H{sub 2}O, CH{sub 2} (paraffinic CH{sub 2}), OH, and COOH for the UJNIFAC model as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the three models. The NRTL equation was the most accurate model in correlating the overall equilibrium compositions of the studied system. The UNIFAC model satisfactorily predicted the equilibrium compositions.

Fahim, M.A.; Al-Muhtaseb, S.A. [United Arab Emirates Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering] [United Arab Emirates Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

1996-11-01

275

Development of a kinetic model for the esterification of acetic acid with methanol in the presence of a homogeneous acid catalyst  

Microsoft Academic Search

The esterification kinetics of acetic acid with methanol in the presence of hydrogen iodide as a homogeneous acid catalyst was studied with isothermal batch experiments at 30–60°C. The catalyst concentration was varied between 0.05 and 10.0 wt%. The experiments revealed that besides the main reaction, the esterification of acetic acid, a side reaction appeared: the catalyst, hydrogen iodide, was esterified

Robert Rönnback; Tapio Salmi; Antti Vuori; Heikki Haario; Juha Lehtonen; Anna Sundqvist; Esko Tirronen

1997-01-01

276

THE USE OF ACETIC ACID IONTOPHORESIS IN THE MANAGEMENT OF A SOFT TISSUE INJURY  

PubMed Central

Background: Contusions are common injuries that occur in athletics. If repeated, complications like myositis ossificans can occur. This case describes the examination and treatment of an athlete with an acute soft tissue injury. Objective: To describe the treatment approach used with a hockey player who sustained a soft tissue injury in his upper extremity. Case Description: A 19 year old male sustained a soft tissue injury to his upper arm while playing hockey. The athlete complained of pain rated a 2-3 out of 10. He had a well circumscribed, firm, 8 by 5 centimeter palpable mass present along the lateral arm, and was able to passively flex his elbow from 56° to 135°, demonstrating a 56° loss of elbow extension. Functionally, he was able to perform most activities of daily living, but he was unable to play hockey. Over 29 days, the athlete was treated one time with pulsed ultrasound and ice and nine times with iontophoresis using a 2% acetic acid solution. Additionally, the athlete performed pain-free active range of motion exercises for the elbow. Outcome: Following treatment, the athlete's pain resolved, the palpable mass disappeared, and his passive range of motion at the elbow was 0° to 135°. Most importantly, the athlete was able to resume playing hockey. Discussion: Acetic acid iontophoresis may be a successful intervention for soft tissue injuries of the upper extremity. In this case, it appeared helpful in decreasing the athlete's impairments and contributed to quicker resumption of all functional activities in less time than previously reported in the literature using traditional treatment interventions.

Ebaugh, David

2010-01-01

277

Pickled egg production: effect of brine acetic Acid concentration and packing conditions on acidification rate.  

PubMed

U.S. federal regulations require that acidified foods must reach a pH of 4.6 or lower within 24 h of packaging or be kept refrigerated until then. Processes and formulations should be designed to satisfy this requirement, unless proper studies demonstrate the safety of other conditions. Our objective was to determine the effect of brine acetic acid concentration and packing conditions on the acidification rate of hard-boiled eggs. Eggs were acidified (60/40 egg-to-brine ratio) at various conditions of brine temperature, heat treatment to filled jars, and postpacking temperature: (i) 25°C/none/25°C (cold fill), (ii) 25°C/none/2°C (cold fill/refrigerated), (iii) 85°C/none/25°C (hot fill), and (iv) 25°C/100°C for 16 min/25°C (water bath). Three brine concentrations were evaluated (7.5, 4.9, and 2.5% acetic acid) and egg pH values (whole, yolk, four points within egg) were measured from 4 to 144 h, with eggs equilibrating at pH 3.8, 4.0, and 4.3, respectively. Experiments were conducted in triplicate, and effects were considered significant when P < 0.05. Multiple linear regression analysis was conducted to evaluate the effect on pH values at the center of the yolk. Regression analysis showed that brine concentration of 2.5% decreased the acidification rate, while packing conditions of the hot fill trial increased it. Inverse prediction was used to determine the time for the center of the yolk and the total yolk to reach a pH value of 4.6. These results demonstrate the importance of conducting acidification studies with proper pH measurements to determine safe conditions to manufacture commercially stable pickled eggs. PMID:24780334

Acosta, Oscar; Gao, Xiaofan; Sullivan, Elizabeth K; Padilla-Zakour, Olga I

2014-05-01

278

Comparison of the high-pressure and low-temperature structures of ethanol and acetic acid  

NASA Astrophysics Data System (ADS)

We have determined the high-pressure crystal structures of ethanol and acetic acid, including the positions of the hydrogen atoms, using a combination of single-crystal x-ray-diffraction techniques and ab initio pseudopotential calculations. We find that in the high-pressure structure of ethanol the molecules are arranged in infinite hydrogen-bonded chains that adopt a structural conformation that is distinctly different from that of the low-temperature form. The hydrogen-bond lengths and bond angles within the chains are equal by symmetry and, as the molecules also have an alternating alignment to the chains, the molecular chains are relatively unstrained. It is proposed that this uniformity and lack of strain within the chains enables ethanol to crystallize much more readily than methanol at high pressure. For acetic acid we find that the molecules are also arranged in infinite hydrogen-bonded chains that are essentially identical to those in the low-temperature structure. However, they adopt markedly different relative orientations, which leads to a more efficient molecular packing and a radically different methyl-methyl contact motif between adjacent molecular chains. The calculated enthalpies of the high-pressure and low-temperature structures show that the high-pressure phase is the most energetically favorable. We find a relatively small 0.056 eV/molecule enthalpy difference between the two structures and this is reflected in the very low freezing pressure of approximately 0.2 GPa at room temperature compared to the freezing temperature of 16 °C at ambient pressure.

Allan, David R.; Clark, Stewart J.

1999-09-01

279

Enhancement of organic solar cells efficiency with acetic acid modulated poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) buffer layers.  

PubMed

Bulk-heterojunction organic solar cells (OSCs) based on poly(3-hexylthiophene) as a donor material and (6.6) phenyl-C61-butyric acid methyl ester as an acceptor material were investigated using a poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) buffer layer that was modulated with acetic acid. The 1.71 x 10(-1) omega x cm resistivity of the pristine PEDOT:PSS film decreased to 2.29 x 10(-2) omega x cm when acetic acid was applied. This modified PEDOT:PSS buffer layer improved the power conversion efficiency (PCE) of OSCs by reducing their already low series resistance and contact resistance. The PCE of OSCs in which the PEDOT:PSS buffer layers had been treated with acetic acid was 2.91%, an improvement over the 1.82% PCE for cells with pristine PEDOT:PSS layers. We optimized the ratio of acetic acid and PEDOT:PSS solution for high PCE of OSCs in this manuscript. The value of this modification method for hole transporting layer is clearly demonstrated and be applicable to other organic devices. PMID:24758027

Oh, Sang Hoon; Heo, Seung Jin; Kim, Hyun Jae

2014-07-01

280

Triamcinolone acetonide acetate.  

PubMed

IN THE CRYSTAL STRUCTURE OF THE TITLE COMPOUND [SYSTEMATIC NAME: 2-(4b-fluoro-5-hy-droxy-4a,6a,8,8-tetra-methyl-2-oxo-2,4a,4b,5,6,6a,9a,10,10a,10b,11,12-dodeca-hydro-7,9-dioxa-penta-leno[2,1-a]phenanthren-6b-yl)-2-oxoethyl acetate], C(26)H(33)FO(7), the mol-ecules are connected by inter-molecular O-H?O hydrogen bonds into an infinite supra-molecular chain along the b axis. The mol-ecular framework consists of five condensed rings, including three six-membered rings and two five-membered rings. The cyclo-hexa-2,5-dienone ring is nearly planar [maximum deviation = 0.013?(3)?Å], while the cyclo-hexane rings adopt chair conformations. The two five-membered rings, viz. cyclo-pentane and 1,3-dioxolane, display envelope conformations. PMID:21523039

Lu, Xiao; Tang, Gu-Ping; Gu, Jian-Ming; Hu, Xiu-Rong

2011-01-01

281

Triamcinolone acetonide acetate  

PubMed Central

In the crystal structure of the title compound [systematic name: 2-(4b-fluoro-5-hy­droxy-4a,6a,8,8-tetra­methyl-2-oxo-2,4a,4b,5,6,6a,9a,10,10a,10b,11,12-dodeca­hydro-7,9-dioxa­penta­leno[2,1-a]phenanthren-6b-yl)-2-oxoethyl acetate], C26H33FO7, the mol­ecules are connected by inter­molecular O—H?O hydrogen bonds into an infinite supra­molecular chain along the b axis. The mol­ecular framework consists of five condensed rings, including three six-membered rings and two five-membered rings. The cyclo­hexa-2,5-dienone ring is nearly planar [maximum deviation = 0.013?(3)?Å], while the cyclo­hexane rings adopt chair conformations. The two five-membered rings, viz. cyclo­pentane and 1,3-dioxolane, display envelope conformations.

Lu, Xiao; Tang, Gu-Ping; Gu, Jian-Ming; Hu, Xiu-Rong

2011-01-01

282

Growth inhibitory effect of grape phenolics against wine spoilage yeasts and acetic acid bacteria.  

PubMed

This paper investigates the in vitro antimicrobial potential of 15 grape phenolic compounds of various chemical classes (phenolic acids, stilbenes and flavonoids) using the broth microdilution method against yeasts and acetic acid bacteria frequently occurring in deteriorated wine. Pterostilbene (MICs=32-128 ?g/mL), resveratrol (MICs=256-512 ?g/mL) and luteolin (MICs=256-512 ?g/mL) are among six active compounds that possessed the strongest inhibitory effects against all microorganisms tested. In the case of phenolic acids, myricetin, p-coumaric and ferulic acids exhibited selective antimicrobial activity (MICs=256-512 ?g/mL), depending upon yeasts and bacteria tested. In comparison with potassium metabisulphite, all microorganisms tested were more susceptible to the phenolics. The results revealed the antibacterial and antiyeast effects against wine spoilage microorganisms of several highly potent phenolics naturally occurring in grapes. These findings also provide arguments for further investigation of stilbenes as prospective compounds reducing the need for the use of sulphites in winemaking. PMID:23334100

Pastorkova, E; Zakova, T; Landa, P; Novakova, J; Vadlejch, J; Kokoska, L

2013-02-15

283

The impact of acetate metabolism on yeast fermentative performance and wine quality: reduction of volatile acidity of grape musts and wines.  

PubMed

Acetic acid is the main component of the volatile acidity of grape musts and wines. It can be formed as a by-product of alcoholic fermentation or as a product of the metabolism of acetic and lactic acid bacteria, which can metabolize residual sugars to increase volatile acidity. Acetic acid has a negative impact on yeast fermentative performance and affects the quality of certain types of wine when present above a given concentration. In this mini-review, we present an overview of fermentation conditions and grape-must composition favoring acetic acid formation, as well the metabolic pathways leading to its formation and degradation by yeast. The negative effect of acetic acid on the fermentative performance of Saccharomyces cerevisiae will also be covered, including its role as a physiological inducer of apoptosis. Finally, currently available wine deacidification processes and new proposed solutions based on zymological deacidification by select S. cerevisiae strains will be discussed. PMID:20931186

Vilela-Moura, Alice; Schuller, Dorit; Mendes-Faia, Arlete; Silva, Rui D; Chaves, Susana R; Sousa, Maria João; Côrte-Real, Manuela

2011-01-01

284

Radiolabeled acetate as a tracer of myocardial tricarboxylic acid cycle flux  

Microsoft Academic Search

The kinetics of (1-14C)acetate oxidation in isolated perfused rat hearts have been determined over a range of perfusion conditions. Effluent measurements demonstrated that 14CO2 cleared biexponentially over 50 minutes after bolus injection of (1-14C)acetate into normoxic hearts perfused with 5 mM glucose and 10 mU\\/ml insulin. The clearance half-time (t1\\/2) for the predominant initial clearance phase was 3.1 +\\/- 0.5

D. B. Buxton; M. Schwaiger; A. Nguyen; M. E. Phelps; H. R. Schelbert

1988-01-01

285

ETHANOL, ACETIC ACID, AND WATER ADSORPTION FROM BINARY AND TERNARY LIQUID MIXTURES ON HIGH-SILICA ZEOLITES  

EPA Science Inventory

Adsorption isotherms were measured for ethanol, acetic acid, and water adsorbed on high-silica ZSM-5 zeolite powder from binary and ternary liquid mixtures at room temperature. Ethanol and water adsorption on two high-silica ZSM-5 zeolites with different aluminum contents and a h...

286

Determination of acetic acid of fruit vinegars using near infrared spectroscopy and least squares-support vector machine  

Microsoft Academic Search

Two chemometric methods were performed for the determination of acetic acid of fruit vinegars using near infrared (NIR) spectroscopy. Three varieties of fruit vinegars were prepared and 135 samples (45 samples for each variety) were selected for the calibration set, whereas 45 samples (15 samples for each variety) for the validation set. Partial least squares (PLS) analysis was the calibration

Fei Liu; Li Wang; Yong He

2008-01-01

287

Resolving the electrospinnability zones and diameter prediction for the electrospinning of the gelatin/water/acetic Acid system.  

PubMed

The development of suitable biomimetic scaffolds is a fundamental requirement of tissue engineering. Although electrospinning has emerged as an effective method for producing such scaffolds of nanometer-sized fibers, the influence of solution characteristics on the morphology of the resulting nanofibers depends on each polymer solution system. In this study, gelatin nanofibers and microfibers were prepared via electrospinning using mixtures of water and acetic acid at different ratios as solvents. The viscosities of gelatin solutions before electrospinning were analyzed and two different behaviors were found as a function of the solvent composition, taking into account classic models of polymer science. A power law relationship between viscosity and gelatin concentration was found for each solvent system, and an empirical model including the influence of acetic acid was obtained for aqueous systems. Moreover, a ternary diagram considering gelatin, water, and acetic acid mass fractions was constructed as a tool to establish the electrospinnability domains in terms of fiber occurrence and morphology. Also, the isodiametric curves were defined in the fibers region. Finally, in order to correlate the diameter of electrospun nanofibers and the electrospinnability zones, the Berry number was used. However, as its only allows the range of electrospinnability to be established for a fixed solvent composition, a new dimensionless parameter (Bemod) was suggested to take into account all the acetic acid aqueous solutions as a single solvent. PMID:24870557

Erencia, Marisa; Cano, Francisco; Tornero, Jose A; Macanás, Jorge; Carrillo, Fernando

2014-06-24

288

Identification and characterization of thermotolerant acetic acid bacteria strains isolated from coconut water vinegar in Sri Lanka.  

PubMed

From the pellicle formed on top of brewing coconut water vinegar in Sri Lanka, three Acetobacter strains (SL13E-2, SL13E-3, and SL13E-4) that grow at 42?°C and four Gluconobacter strains (SL13-5, SL13-6, SL13-7, and SL13-8) grow at 37?°C were identified as Acetobacter pasteurianus and Gluconobacter frateurii, respectively. Acetic acid production by the isolated Acetobacter strains was examined. All three strains gave 4% acetic acid from 6% initial ethanol at 37?°C, and 2.5% acetic acid from 4% initial ethanol at 40?°C. Compared with the two other strains, SL13E-4 showed both slower growth and slower acetic acid production. As well as the thermotolerant SKU1108 strain, the activities of the alcohol dehydrogenase and the aldehyde dehydrogenase of SL13E-2 and SL13E-4 were more stable than those of the mesophilic strain. The isolated strains were used to produce coconut water vinegar at higher temperatures than typically used for vinegar production. PMID:25036846

Perumpuli, P A B N; Watanabe, Taisuke; Toyama, Hirohide

2014-03-01

289

Selective removal of the cobalt binder in WC\\/Co based hardmetal scraps by acetic acid leaching  

Microsoft Academic Search

Scraps of hardmetal tools and pieces of original size were contacted with aqueous solutions of acetic acid under simultaneous introduction of pure oxygen or air to dissolve selectively the cobalt binder and recover the tungsten carbide. The influences of nominal composition of the scrap on the necessary time for a complete removal of the binder, as well as temperature, concentration

C. Edtmaier; R. Schiesser; C. Meissl; W. D. Schubert; A. Bock; A. Schoen; B. Zeiler

2005-01-01

290

The effects of citric and acetic acids on the formation of calcium-deficient hydroxyapatite at 38 °C  

Microsoft Academic Search

This study is concerned with the formation of calcium-deficient hydroxyapatite at physiological temperature. Isothermal calorimetry, solution chemistry, scanning electron microscopy, BET surface area analyses and FTIR spectroscopy were used to characterize the kinetics of HAp formation and the microstructure of the HAp formed in varying concentrations of citric and acetic acids, and in deionized water. The kinetics of HAp formation

K. S. Tenhuisen; P. W. Brown

1994-01-01

291

Gluconacetobacter medellinensis sp. nov., cellulose- and non-cellulose-producing acetic acid bacteria isolated from vinegar.  

PubMed

The phylogenetic position of a cellulose-producing acetic acid bacterium, strain ID13488, isolated from commercially available Colombian homemade fruit vinegar, was investigated. Analyses using nearly complete 16S rRNA gene sequences, nearly complete 16S-23S rRNA gene internal transcribed spacer (ITS) sequences, as well as concatenated partial sequences of the housekeeping genes dnaK, groEL and rpoB, allocated the micro-organism to the genus Gluconacetobacter, and more precisely to the Gluconacetobacter xylinus group. Moreover, the data suggested that the micro-organism belongs to a novel species in this genus, together with LMG 1693(T), a non-cellulose-producing strain isolated from vinegar by Kondo and previously classified as a strain of Gluconacetobacter xylinus. DNA-DNA hybridizations confirmed this finding, revealing a DNA-DNA relatedness value of 81?% between strains ID13488 and LMG 1693(T), and values <70?% between strain LMG 1693(T) and the type strains of the closest phylogenetic neighbours. Additionally, the classification of strains ID13488 and LMG 1693(T) into a single novel species was supported by amplified fragment length polymorphism (AFLP) and (GTG)5-PCR DNA fingerprinting data, as well as by phenotypic data. Strains ID13488 and LMG 1693(T) could be differentiated from closely related species of the genus Gluconacetobacter by their ability to produce 2- and 5-keto-d-gluconic acid from d-glucose, their ability to produce acid from sucrose, but not from 1-propanol, and their ability to grow on 3?% ethanol in the absence of acetic acid and on ethanol, d-ribose, d-xylose, sucrose, sorbitol, d-mannitol and d-gluconate as carbon sources. The DNA G+C content of strains ID13488 and LMG 1693(T) was 58.0 and 60.7 mol%, respectively. The major ubiquinone of LMG 1693(T) was Q-10. Taken together these data indicate that strains ID13488 and LMG 1693(T) represent a novel species of the genus Gluconacetobacter for which the name Gluconacetobacter medellinensis sp. nov. is proposed. The type strain is LMG 1693(T) (?=?NBRC 3288(T)?=?Kondo 51(T)). PMID:22729025

Castro, Cristina; Cleenwerck, Ilse; Trcek, Janja; Zuluaga, Robin; De Vos, Paul; Caro, Gloria; Aguirre, Ricardo; Putaux, Jean-Luc; Gañán, Piedad

2013-03-01

292

Calibration and intercomparison of acetic acid measurements using proton-transfer-reaction mass spectrometry (PTR-MS)  

NASA Astrophysics Data System (ADS)

Acetic acid is one of the most abundant organic acids in the ambient atmosphere, with maximum mixing ratios reaching into the tens of parts per billion by volume (ppbv) range. The identities and associated magnitudes of the major sources and sinks for acetic acid are poorly characterized, due in part to the limitations of available measurement techniques. This paper demonstrates that, when properly calibrated, proton-transfer-reaction mass spectrometry (PTR-MS) can be a valuable technique for fast response, accurate quantification of acetic acid in ambient air. Three different PTR-MS configurations were calibrated at low ppbv mixing ratios using permeation tubes, which yielded calibration factors between 7.0 and 10.9 normalized counts per second per ppbv (ncps ppbv-1) at a drift tube field strength of 132 Townsend (Td). Detection limits ranged from 0.06 to 0.32 ppbv with dwell times of 5 s. These calibration factors showed negligible humidity dependence. Acetic acid was measured with PTR-MS on Appledore B Island, ME, during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) campaign and validated based on acetic acid measured in parallel using tandem mist chambers coupled with ion chromatography (MC/IC). Mixing ratios ranged from a minimum of 0.075 ± 0.004 ppbv to 3.555 ± 0.171 ppbv, with a median mixing ratio of 0.530 ± 0.025 ppbv. An orthogonal least squares linear regression of paired data yielded a slope of 1.14 ± 0.06 (2?), an intercept of 0.049 ± 0.020 (2?) ppbv, and an R2 of 0.78.

Haase, K. B.; Keene, W. C.; Pszenny, A. A. P.; Mayne, H. R.; Talbot, R. W.; Sive, B. C.

2012-11-01

293

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

294

Molecular Structure of Sodium acetate  

NSDL National Science Digital Library

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

2002-08-26

295

The use of acetic acid as a source of carbon by cultured Chondrus crispus (Gigartinales, Rhodophyta) stackhouse  

Microsoft Academic Search

When growing seaweeds in tanks, pH and carbon source supply have to be controlled in order to maximize photosynthesis. pH can be controlled either by adding various inorganic acids which requires the extra addition of carbon, or by combining pH control and carbon source with for instance CO2 or an organic acid such as acetic acid (CH3COOH). We have found

Mireille A. Amat; Jean-Paul Braud

1993-01-01

296

Bio-available amino acids extraction from soil by demineralized water and 0.5 M ammonium acetate.  

PubMed

The extraction and comparison of soil bio-available amino acids using either demineralised water (DEMI H(2)O) or 0.5 M ammonium acetate (0.5 M AAc) solution is reported. Results show that the extraction by 0.5 M AAc is a better method to assess the concentration of bio-available amino acids in soil than DEMI H(2)O due to higher extraction efficiency and better amino acid protection against microbial degradation during processing. PMID:15838591

Formánek, P; Klejdus, B; Vranová, V

2005-06-01

297

Responses of Mitrella lunata and Caprella spp., potential tunicate micropredators, in Prince Edward Island estuaries to acetic acid anti-fouling treatments  

Microsoft Academic Search

In Prince Edward Island, Canada, acetic acid treatments that are used to control the clubbed tunicate (Styela clava), a fouling pest on mussel lines, may also affect other epifaunal mussel sock species, including potential tunicate predators. We studied the effect of acetic acid treatment on two potential predators of the tunicates, the gastropod Mitrella lunata (lunar dove shell) and the

S. Christine Paetzold; Jeff Davidson; Donna Giberson

2008-01-01

298

Short chain fatty acid distributions of enema samples from a sigmoidoscopy population: an association of high acetate and low butyrate ratios with adenomatous polyps and colon cancer  

Microsoft Academic Search

We investigated the distribution of short chain fatty acids (SCFA) in enema samples taken from subjects before sigmoidoscopy as an indicator of possible microbial community differences between subjects subsequently diagnosed as normal or having colonic disorders. The major SCFA in all groups were acetic, propionic, and butyric acids. A significantly higher ratio of acetate to total SCFA and lower ratio

G A Weaver; J A Krause; T L Miller; M J Wolin

1988-01-01

299

Esters of (1,2, 5-trimethyl-4-hydroxy-4-piperedyl)- and phenyl-(1,2, 5-trimethyl-4-hydroxy-4-piperidyl) acetic acids  

Microsoft Academic Search

The methyl ester of a new hydroxy acid of the piperidine series (a-phenyl-a-(1,2, 5-trimethyl-4-hydroxy 4-piperidyl)acetic acid) has been prepared. Ethyl a-(1,2, 5-trimethyl-4-hydroxy-4-piperidyl)acetate has been converted into the substituted pyridine, 1,1-diphenyl-2-(2'-5'-dimethyl-4-pyridyl)ethylene.

N. S. Prostakov; V. G. Pleshakov; V. V. Dorogov; V. P. Zvolinskii

1970-01-01

300

NMR-spectroscopic evidence of intermediate-dependent pathways for acetic acid formation from methane and carbon monoxide over a ZnZSM-5 zeolite catalyst.  

PubMed

Two ways: a Zn-modified ZSM-5 zeolite catalyst was developed for the reaction of methane with carbon monoxide to directly produce acetic acid under mild conditions (573-623 K), and two different intermediate-dependent reaction pathways were unambiguously identified for acetic acid formation by in situ solid-state NMR spectroscopy. PMID:22389151

Wang, Xiumei; Qi, Guodong; Xu, Jun; Li, Bojie; Wang, Chao; Deng, Feng

2012-04-16

301

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

302

Root-uptake of (14)C derived from acetic acid and (14)C transfer to rice edible parts.  

PubMed

Three types of culture experiments using paddy rice (Oryza sativa L.) were performed to examine root-uptake of (14)C in the form of acetic acid: double pot experiment (hydroponics), wet culture experiment (submerged sand medium), and chamber experiment (hydroponics and submerged sand medium). The (14)C radioactivity in the plant, mediums, and atmospheric carbon dioxide ((14)CO(2)) in the chamber were determined, and the distribution of (14)C in the plant was visualized using autoradiography. In the double pot experiment, the shoot of the plant and the lower root which was soaked in the culture solution had (14)C radioactivity, but the upper root which did not have contact with the solution had none. There were also (14)C radioactivity in the grains and roots in the wet culture experiment. Results of the chamber experiment showed that (14)CO(2) gas was released from the culture solution in both types of cultures. Results indicated that the (14)C-acetic acid absorbed by rice plant through its root would be very small. Most of the (14)C-acetic acid was transformed into gaseous forms either in the culture solution or rhizosphere. A relatively longer time would be needed to assimilate (14)C derived from acetic acid to grain parts after it was once absorbed by the shoot through the root. Availability of (14)C for the plant in sand culture was considered to be decreased compared with that for the plant in the hydroponics experiment. It was suggested that rice plant absorbed and assimilated (14)C through the plant roots not because of uptake of (14)C-acetic acid but because of uptake of (14)C in gaseous forms such as (14)CO(2). PMID:19962904

Ogiyama, Shinichi; Suzuki, Hiroyuki; Inubushi, Kazuyuki; Takeda, Hiroshi; Uchida, Shigeo

2010-02-01

303

Lewis acid-catalyzed intramolecular condensation of ynol ether-acetals. Synthesis of alkoxycycloalkene carboxylates  

PubMed Central

Treatment of ynol ether-tethered dialkyl acetals with catalytic quantities of scandium triflate in CH3CN gives rise to five-, six-, and seven-membered alkoxycycloalkene carboxylates in good to excellent yields. Trisubstituted and tetrasubsituted carbocyclic and heterocyclic alkenes may be formed by this method, and the products obtained may serve as useful intermediates for natural product synthesis.

Tran, Vincent

2012-01-01

304

Indole-3-acetic acid/horseradish peroxidase induces apoptosis in TCCSUP human urinary bladder carcinoma cells.  

PubMed

Indole-3-acetic acid (IAA) and horseradish peroxidase (HRP) have emerged as a new strategy for cancer treatment. In the present study, we determined the effects of IAA/HRP treatment on TCCSUP human urinary bladder carcinoma cells. It was found that the IAA/HRP combination decreased cell viability of TCCSUP cells in a time- and dose-dependent manner, whereas IAA or HRP alone showed no such effect. In addition, the decreased cell viability was restored by pretreatment with ascorbic acid. To clarify the mechanism of death of TCCSUP cells by IAA/HRP, we investigated the signal transduction pathways related to the apoptosis. It was found that IAA/HRP activates p38 mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK). We further investigated the IAA/HRP-mediated apoptotic pathways and showed that IAA/HRP induces caspase-8 and caspase-9 activation, which results in caspase-3 activation and poly(ADP-ribose) polymerase (PARP) cleavage. To further confirm whether IAA/HRP induces apoptotic cell death, we performed a DNA fragmentation assay after IAA/HRP treatment and found that IAA/HRP-treated cells showed typical apoptotic DNA ladder formation. From these results, we suggest that IAA/HRP induces apoptosis of TCCSUP human urinary bladder carcinoma cells via both death receptor-mediated and mitochondrial apoptotic pathways. PMID:20225657

Jeong, Yun-Mi; Oh, Mi Hee; Kim, Su Yeon; Li, Hailan; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Kim, Won Yong; Kim, Dong-Seok

2010-02-01

305

Phase equilibria of the ternary system water + acetic acid + 1-pentanol  

SciTech Connect

The recovery of organic acids from dilute solutions resulting from fermentation processes is becoming very important and many solvents have been tried to improve such recovery. Liquid-liquid equilibria for the ternary system water + acetic acid + 1-pentanol were measured over a temperature range of (288 to 323) K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models and between each of the main groups of H{sub 2}O, CH{sub 2} (paraffinic CH{sub 2}), OH, and COOH for the UNIFAC model as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the three models. The NRTL and UNIQUAC models were almost equally good in predicting the overall equilibrium compositions of the studied system. The UNIFAC model satisfactorily predicted the equilibrium compositions. On the basis of this work, the distribution coefficients were also calculated and compared with the experimental values.

Fahim, M.A.; Al-Muhtaseb, S.A.; Al-Nashef, I.M. [U.A.E. Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering] [U.A.E. Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

1996-05-01

306

Acetic acid treatments to keep postharvest quality of "Regina" and "Taloppo" table grapes.  

PubMed

The most important postharvest pathogen for table grape is Botrytis cinerea (gray mold), which cause a rapid deterioration of fruit. An effective control of the disease during storage is difficult and remains an unsolved problem since no pesticide treatments are allowed by European legislation. GRAS compounds, employed with no restriction as preservatives in Europe and North America, are possible candidates to fulfil this gap. The aim of this work is to study the efficacy of Acetic Acid (AAC), used as postharvest treatment to control Botrytis cinerea on "Regina" and "Taloppo" table grapes, by Laboratory and storage tests. The activity of this compound was first assessed with laboratory tests, treating at different concentrations (0, 5, 10, 20, 50, 75 and 100 microl/L) of AAC vapors, for 15 minutes, single berries inoculated with B. cinerea. After treatments fruit was incubated at 20 degrees C for one week. The in vivo experiment took place by using the most promising AAC concentrations (50, 75 and 100 microl/L) followed by eight weeks of storage at 5 degrees C and 95% of relative humidity (RH) and four days at 20 degrees C and 85% RH (simulated shelf-life conditions). At the end of the in vivo experiment decay, weight loss and visual assessment were evaluated. Almost all treatments, after eight weeks of storage, reduced the incidence of gray mould. The best results were achieved by using 50 ppm of AAC, gaining a reduction of decay, compared to untreated "Taloppo" and "Regina" grapes of 61.0% and 41.4%, respectively. Following the simulated shelf-life period differences between treated and untreated (control) became no significant for "Taloppo" grape, while the lowest decay percentage was reached with 50 microl/L of AAC for "Regina" grape (52% of reduction if compared to control). Regarding fruit weight loss all treatments did not affect significantly this parameter that ranged between 8.2% and 11.5% after eight weeks of storage and 13.5% and 18.2% after shelf-life. At the end of storage the highest visual score was attributed to fruit treated with 50 microl/L of AAC evidencing a clear better keeping quality. During this period slight treatment damages were observed on berries following application of AAC at 75 and 100 microl/L. The reported results obtained with these experiments showed that Acetic Acid could be a promising compound to be used as alternative to SO2 in keeping grapes quality and controlling decay during storage. PMID:19226763

Venditti, T; D'Hallewin, G; Dore, A; Molinu, M G; Fiori, P; Angiolino, C; Agabbio, M

2008-01-01

307

Acetate catabolism by Methanosarcina barkeri  

SciTech Connect

Cell suspensions of Methanosarcina barkeri convert the carboxyl and methyl group carbons of acetate to carbon dioxide and methane at pH 6 under an atmosphere of 100% CO/sub 2/. The rate of loss of radioactivity from (1-/sup 14/C)acetate was over three times greater than that from (2-/sup 14/C)acetate under these conditions. Control experiments with both labeled substrates present showed that the rates were additive. Addition of a high level of 2-bromoethanesulfonate to selectively inhibit methane formation largely inhibited release of /sup 14/C from methyl-labeled acetate but only marginally decreased the rate of loss from (1-/sup 14/C)acetate. Thus, in the absence of the inhibitor loss of /sup 14/C from (1-/sup 14/C)acetate likely reflects an isotopic exchange reaction with CO/sub 2/ superimposed on the overall conversion of acetate to CO/sub 2/ and CH/sub 4/. The exchange reaction was inhibited by uncouplers such as 2,4-dinitrophenol, CCCP, and FCCP. Cells permeabilized by treatment with nonionic detergents or disrupted by passage through a French pressure cell failed to catalyze the exchange reaction. Exchange activity was not restored by addition of ATP or by use of (1-/sup 14/C)acetyl CoA as substrate. No evidence for involvement of carbon monoxide dehydrogenase in the exchange was found in these experiments when CO/sub 2/ was replaced by CO. However, the soluble extracts retained the ability to convert acetate to methane in the presence of H/sub 2/ and ATP.

Grahame, D.A.

1987-05-01

308

Synthesis of acetic-methacrylic acid diesters of norbornane-2,5-diol and (2-hydroxynorborn-5-yl)methanol  

Microsoft Academic Search

Reaction of addition of acrylic acids to 5-acetoxy- and 5-acetoxymethylnorborn-2-ene in the presence of a BF3·O(C2H5)2 catalyst was studied in order to synthesize mixed acetic-acrylic acid diesters of norbornane-2,5-diol and (2-hydroxynorborn-5-yl)methanol,\\u000a which are new monomers for syntheses of polymers.

M. K. Mamedov; V. S. Kadyrly

2010-01-01

309

Synthesis and in vitro antimicrobial activity of novel 2-(3-oxo-1,3-diarylpropylthio)acetic acid derivatives.  

PubMed

A series of novel 2-(3-oxo-1,3-diarylpropylthio)acetic acid derivatives (3a-l) were prepared by base catalyzed addition of thioglycolic acid to chalcones (1a-l). The antibacterial activities of synthesized compounds were screened against human pathogenic microorganisms by employing the disk-diffusion technique. For the active compounds, also minimum inhibitory concentrations (MICs) were determined. PMID:23061285

Gezegen, Hayreddin; Karaman, Isa; Ceylan, Mustafa; Dilmaç, Merve

2012-01-01

310

Induction of bovine bronchial epithelial cell filopodia by tetradecanoyl phorbol acetate, calcium ionophore, and lysophosphatidic acid.  

PubMed

The morphological responses of primary bovine bronchial epithelial cells (BBECs) cultured in serum-free medium to protein activators have been examined. When attached to type I collagen-coated tissue culture dishes, the cells responded to tetradecanoyl phorbol acetate (TPA), calcium ionophore A23187, and lysophosphatidic acid (LPA) by extruding filopodia. In contrast, no morphological changes were elicited by exposures to either epinephrine or dibutyryl-cAMP. Formation of filopodia was accompanied by actin filament reorganization as demonstrated by staining with labeled phalloidin. Exposures to varied TPA concentrations for 2 h showed maximal stimulation of filopodial extrusions at 10 nM TPA with half-maximal stimulation at 1 nM. Time-course measurements with 10 nM TPA showed filopodia formation within 30 min of exposure, with 85% of the BBECs being filopodia positive after 5 h. Filopodia induction in 20-30% of the cells could be achieved by 1-100 microM LPA concentrations. BBECs acquired increasing resistance to TPA-induced filopodia during the initial 5 days in culture; however, responsiveness to TPA was regenerated by mild treatment with trypsin. Inclusion of fibronectin or vitronectin into the attachment matrix had no effects on the rates or extent of TPA-induced filopodia formation. PMID:7540618

Beckmann, J D; Romberger, D J; Rennard, S I; Spurzem, J R

1995-07-01

311

Modulation of Endogenous Indole-3-Acetic Acid Biosynthesis in Bacteroids within Medicago sativa Nodules.  

PubMed

To evaluate the dose-response effects of endogenous indole-3-acetic acid (IAA) on Medicago plant growth and dry weight production, we increased the synthesis of IAA in both free-living and symbiosis-stage rhizobial bacteroids during Rhizobium-legume symbiosis. For this purpose, site-directed mutagenesis was applied to modify an 85-bp promoter sequence, driving the expression of iaaM and tms2 genes for IAA biosynthesis. A positive correlation was found between the higher expression of IAA biosynthetic genes in free-living bacteria and the increased production of IAA under both free-living and symbiotic conditions. Plants nodulated by RD65 and RD66 strains, synthetizing the highest IAA concentration, showed a significant (up to 73%) increase in the shoot fresh weight and upregulation of nitrogenase gene, nifH, compared to plants nodulated by the wild-type strain. When these plants were analyzed by confocal microscopy, using an anti-IAA antibody, the strongest signal was observed in bacteroids of Medicago sativa RD66 (Ms-RD66) plants, even when they were located in the senescent nodule zone. We show here a simple system to modulate endogenous IAA biosynthesis in bacteria nodulating legumes suitable to investigate which is the maximum level of IAA biosynthesis, resulting in the maximal increase of plant growth. PMID:24814784

Bianco, C; Senatore, B; Arbucci, S; Pieraccini, G; Defez, R

2014-07-15

312

Photo-activated 5-hydroxyindole-3-acetic acid induces apoptosis of prostate and bladder cancer cells.  

PubMed

5-Hydroxyindole-3-acetic acid (5-HIAA), an indole derivative, is the main metabolite of serotonin in the human body. We determined whether or not ultraviolet B (UVB)-activated 5-HIAA (5-HIAA(UVB)) affects the viability of human prostate (LnCaP and PC-3) and bladder cancer cells (TCCSUP). While 5-HIAA alone had no cytotoxic effect at <1mM, 5-HIAA(UVB) induced LnCaP, PC-3, and TCCSUP cell death in a time- and dose-dependent manner. Cell cycle analysis showed that 5-HIAA(UVB) markedly increased the sub-G(0)/G(1) phase and resulted in cell cycle disruption. To elucidate the death mechanism by 5-HIAA(UVB), we examined the signal transduction pathways related to apoptosis using Western blot analysis. 5-HIAA(UVB) led to phosphorylation of stress-activated signaling proteins, such as c-Jun N-terminal kinase (JNK) and/or p38 mitogen-activated protein kinase (MAPK). Furthermore, 5-HIAA(UVB) activated caspase-8, -9, and -3 and cleaved poly(ADP-ribose) polymerase (PARP), which are indicators of apoptosis. From these findings, the present study demonstrated that 5-HIAA(UVB) induces apoptotic cell death of prostate and bladder cancer cells via stress-mediated signaling and apoptotic pathways. Therefore, we suggest that 5-HIAA might be used as a new photosensitizer for photodynamic cancer therapy. PMID:21310627

Jeong, Yun-Mi; Li, Hailan; Kim, Su Yeon; Park, Woo-Jae; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Jeong, Ji Hoon; Myung, Soon Chul; Kim, Dong-Seok

2011-04-01

313

Indole-3-acetic acid production by endophytic Streptomyces sp. En-1 isolated from medicinal plants.  

PubMed

Plant-associated actinobacteria are rich sources of bioactive compounds including indole-derived molecules such as phytohormone indole-3-acetic acid (IAA). In view of few investigations concerning the biosynthesis of IAA by endophytic actinobacteria, this study evaluated the potential of IAA production in endophytic streptomycete isolates sourced from medicinal plant species Taxus chinensis and Artemisia annua. By HPLC analysis of IAA combined with molecular screening approach of iaaM, a genetic determinant of streptomycete IAA synthesis via indole-3-acetamide (IAM), our data showed the putative operation of IAM-mediated IAA biosynthesis in Streptomyces sp. En-1 endophytic to Taxus chinensis. Furthermore, using the co-cultivation system of model plant Arabidopsis thaliana and streptomycete, En-1 was found to be colonized intercellularly in the tissues of Arabidopsis, an alternative host, and the effects of endophytic En-1 inoculation on the model plant were also assayed. The phytostimulatory effects of En-1 inoculation suggest that IAA-producing Streptomyces sp. En-1 of endophytic origin could be a promising candidate for utilization in growth improvement of plants of economic and agricultural value. PMID:23512121

Lin, Lan; Xu, Xudong

2013-08-01

314

Nutrient Salts Promote Light-Induced Degradation of Indole-3-Acetic Acid in Tissue Culture Media  

PubMed Central

The disappearance of indole-3-acetic acid (IAA) from cell-free liquid culture medium was followed in response to nutrient salts found in Murashige-Skoog salt base, light, and pH range of 4 to 7. The loss of IAA was accelerated by light or Murashige-Skoog salts. However, the combination of both light and Murashige-Skoog salts acted synergistically to catalyze the destruction of over 80% of the original IAA within 7 days of continuous incubation. Under these same conditions, the loss of IAA was decreased to approximately 50% by adjusting the initial pH of the medium to 7. Iron was identified as the single major contributor to light-catalyzed destruction of IAA. Removal of nitrates, which represented 87% of the molar salt composition, also reduced the light-catalyzed loss of IAA. Treatments that protected IAA from degradation, such as darkness or removal of iron from the medium, suppressed the growth of muskmelon (Cucumis melo. Naud., var. reticulatus) callus tissue cultured for 30 days. Treatments in the light that rapidly degraded IAA resulted in maximum growth. Consequently, the brief exposure to IAA prior to degradation was apparently sufficient to initiate physiological changes required for growth. Possible approaches to the preservation of IAA during incubation are discussed.

Dunlap, James R.; Robacker, Karen M.

1988-01-01

315

Enhancement of lipid peroxidation by indole-3-acetic acid and derivatives: substituent effects.  

PubMed

The peroxidation of liposomes by a haem peroxidase and hydrogen peroxide in the presence of indole-3-acetic acid and derivatives was investigated. It was found that these compounds can accelerate the lipid peroxidation up to 65 fold and this is attributed to the formation of peroxyl radicals that may react with the lipids, possibly by hydrogen abstraction. The peroxyl radicals are formed by peroxidase-catalyzed oxidation of the enhancers to radical cations which undergo cleavage of the carbon-carbon bond on the side-chain to yield CO2 and carbon-centred radicals that rapidly add oxygen. In competition with decarboxylation, the radical cations deprotonate reversibly from the N1 position. Rates of decarboxylation, pka values and rate of reaction with the peroxidase compound I indicate consistent substituent effects which, however, can not be quantitatively related to the usual Hammett or Brown parameters. Assuming that the rate of decarboxylation of the radical cations taken is a measure of the electron density of the molecule (or radical), it is found that the efficiency of these compounds as enhancers of lipid peroxidation increases with increasing electron density, suggesting that, at least in the model system, the oxidation of the substrates is the limiting step in causing lipid peroxidation. PMID:7581824

Candeias, L P; Folkes, L K; Porssa, M; Parrick, J; Wardman, P

1995-11-01

316

Large-scale gaseous acetic acid treatment to disinfect alfalfa seeds inoculated with Escherichia coli.  

PubMed

Most outbreaks of foodborne illness related to sprout consumption are ascribed to bacterial contamination of its seeds, and they need disinfection before sprouting. Recently, gaseous acetic acid (GAA) treatment received great attention as a method for seed disinfection. In this study, the effect of GAA treatment on alfalfa seed disinfection was evaluated in a large-scale device to simulate practical applications. Alfalfa seeds (3?kg) inoculated with Escherichia coli were treated with 8.7% (vol/vol) GAA at 55°C for 1-3?h. The population of E. coli was significantly reduced (p<0.05), and the reduction was larger with longer exposure times. After 3-h treatment, a maximum decrease by more than 5 log colony-forming units/g was observed. The germination ratio of alfalfa seeds was not affected by the treatments under all the conditions. The results indicated that the GAA treatment has a potential for practical application to reduce the risk of foodborne illness caused by consumption of sprouts. PMID:24400985

Nei, Daisuke; Enomoto, Katsuyoshi; Yamamoto, Kazutaka

2014-04-01

317

Strain typing of acetic acid bacteria responsible for vinegar production by the submerged elaboration method.  

PubMed

Strain typing of 103 acetic acid bacteria isolates from vinegars elaborated by the submerged method from ciders, wines and spirit ethanol, was carried on in this study. Two different molecular methods were utilised: pulsed field gel electrophoresis (PFGE) of total DNA digests with a number of restriction enzymes, and enterobacterial repetitive intergenic consensus (ERIC) - PCR analysis. The comparative study of both methods showed that restriction fragment PFGE of SpeI digests of total DNA was a suitable method for strain typing and for determining which strains were present in vinegar fermentations. Results showed that strains of the species Gluconacetobacter europaeus were the most frequent leader strains of fermentations by the submerged method in the studied vinegars, and among them strain R1 was the predominant one. Results showed as well that mixed populations (at least two different strains) occurred in vinegars from cider and wine, whereas unique strains were found in spirit vinegars, which offered the most stressing conditions for bacterial growth. PMID:20832673

Fernández-Pérez, Rocío; Torres, Carmen; Sanz, Susana; Ruiz-Larrea, Fernanda

2010-12-01

318

Acetal-Derivatized Dextran: An Acid-Responsive Biodegradable Material for Therapeutic Applications  

PubMed Central

Dextran, a biocompatible, water-soluble polysaccharide, was modified at its hydroxyls with acetal moieties such that it became insoluble in water but freely soluble in common organic solvents enabling its use in the facile preparation of acid-sensitive microparticles. These particles degrade in a pH-dependent manner: FITC-dextran was released with a half-life at 37 ºC of 10 hours at pH 5.0 compared to a half-life of approximately 15 days at pH 7.4. Both hydrophobic and hydrophilic cargoes were successfully loaded into these particles using single and double emulsion techniques, respectively. When used in a model vaccine application, particles loaded with the protein ovalbumin (OVA) increased the presentation of OVA-derived peptides to CD8+ T-cells 16-fold relative to OVA alone. Additionally, this dextran derivative was found to be non-toxic in preliminary in vitro cytotoxicity assays. Due to its ease of preparation, processability, pH-sensitivity, and biocompatibility, this type of modified dextran should find use in numerous drug delivery applications.

Bachelder, Eric M.; Beaudette, Tristan T.; Broaders, Kyle E.; Dashe, Jesse; Frechet, Jean M. J.

2009-01-01

319

Diversity of acetic acid bacteria present in healthy grapes from the Canary Islands.  

PubMed

The identification of acetic acid bacteria (AAB) from sound grapes from the Canary Islands is reported in the present study. No direct recovery of bacteria was possible in the most commonly used medium, so microvinifications were performed on grapes from Tenerife, La Palma and Lanzarote islands. Up to 396 AAB were isolated from those microvinifications and identified by 16S rRNA gene sequencing and phylogenetic analysis. With this method, Acetobacter pasteurianus, Acetobacter tropicalis, Gluconobacter japonicus and Gluconacetobacter saccharivorans were identified. However, no discrimination between the closely related species Acetobacter malorum and Acetobacter cerevisiae was possible. As previously described, 16S-23S rRNA gene internal transcribed spacer (ITS) region phylogenetic analysis was required to classify isolates as one of those species. These two species were the most frequently occurring, accounting for more than 60% of the isolates. For typing the AAB isolates, both the Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR and (GTG)5-PCR techniques gave similar resolution. A total of 60 profiles were identified. Thirteen of these profiles were found in more than one vineyard, and only one profile was found on two different islands (Tenerife and La Palma). PMID:21903289

Valera, Maria José; Laich, Federico; González, Sara S; Torija, Maria Jesús; Mateo, Estibaliz; Mas, Albert

2011-11-15

320

Gluconobacter as Well as Asaia Species, Newly Emerging Opportunistic Human Pathogens among Acetic Acid Bacteria ? †  

PubMed Central

Acetic acid bacteria (AAB) are broadly used in industrial food processing. Among them, members of the genera Asaia, Acetobacter, and Granulibacter were recently reported to be human opportunistic pathogens. We isolated AAB from clinical samples from three patients and describe here the clinical and bacteriological features of these cases. We report for the first time (i) the isolation of a Gluconobacter sp. from human clinical samples; (ii) the successive isolation of different AAB, i.e., an Asaia sp. and two unrelated Gluconobacter spp., from a cystic fibrosis patient; and (iii) persistent colonization of the respiratory tract by a Gluconobacter sp. in this patient. We reviewed the main clinical features associated with AAB isolation identified in the 10 documented reports currently available in the literature. Albeit rare, infections as well as colonization with AAB are increasingly reported in patients with underlying chronic diseases and/or indwelling devices. Clinicians as well as medical microbiologists should be aware of these unusual opportunistic pathogens, which are difficult to detect during standard medical microbiological investigations and which are multiresistant to antimicrobial agents. Molecular methods are required for identification of genera of AAB, but the results may remain inconclusive for identification to the species level.

Alauzet, Corentine; Teyssier, Corinne; Jumas-Bilak, Estelle; Gouby, Anne; Chiron, Raphael; Rabaud, Christian; Counil, Francois; Lozniewski, Alain; Marchandin, Helene

2010-01-01

321

Endohyphal Bacterium Enhances Production of Indole-3-Acetic Acid by a Foliar Fungal Endophyte  

PubMed Central

Numerous plant pathogens, rhizosphere symbionts, and endophytic bacteria and yeasts produce the important phytohormone indole-3-acetic acid (IAA), often with profound effects on host plants. However, to date IAA production has not been documented among foliar endophytes -- the diverse guild of primarily filamentous Ascomycota that live within healthy, above-ground tissues of all plant species studied thus far. Recently bacteria that live within hyphae of endophytes (endohyphal bacteria) have been detected, but their effects have not been studied previously. Here we show not only that IAA is produced in vitro by a foliar endophyte (here identified as Pestalotiopsis aff. neglecta, Xylariales), but that IAA production is enhanced significantly when the endophyte hosts an endohyphal bacterium (here identified as Luteibacter sp., Xanthomonadales). Both the endophyte and the endophyte/bacterium complex appear to rely on an L-tryptophan dependent pathway for IAA synthesis. The bacterium can be isolated from the fungus when the symbiotic complex is cultivated at 36°C. In pure culture the bacterium does not produce IAA. Culture filtrate from the endophyte-bacterium complex significantly enhances growth of tomato in vitro relative to controls and to filtrate from the endophyte alone. Together these results speak to a facultative symbiosis between an endophyte and endohyphal bacterium that strongly influences IAA production, providing a new framework in which to explore endophyte-plant interactions.

Hoffman, Michele T.; Gunatilaka, Malkanthi K.; Wijeratne, Kithsiri; Gunatilaka, Leslie; Arnold, A. Elizabeth

2013-01-01

322

Temperature-Sensitive Plant Cells with Shunted Indole-3-Acetic Acid Conjugation.  

PubMed Central

Cells of henbane (Hyoscyamus muticus L.) grow indefinitely in culture without exogenous auxin. Cells of its temperature-sensitive variant XIIB2 grow like the wild type at 26[deg]C but die rapidly at 33[deg]C unless auxin is added to the medium. Despite this temperature-sensitive auxin auxotrophy, XIIB2 produces wild-type amounts of indole-3-acetic acid (IAA). IAA is the predominant auxin and is important for plant growth and development. Since the IAA production of the variant is functional, we investigated whether the synthesis or degradation of IAA metabolites, possibly active auxins themselves, is altered. The IAA metabolites were IAA-aspartate (IAAsp) and IAA-glucose. The wild type converted IAA mainly to IAAsp, whereas the variant produced mainly IAA-glucose. Exogenous auxin corrected the shunted IAA metabolism of the variant. The half-life of labeled IAAsp in the variant was reduced 21-fold, but in the presence of exogenous auxin it was not different from the wild type. The temperature sensitivity of XIIB2 was also corrected by supplying IAAsp. Pulse-chase experiments revealed that henbane rapidly metabolizes IAAsp to compounds not identical to IAA. The data show that the variant XIIB2 is a useful tool to study the function of IAA conjugates to challenge the popular hypothesis that IAA conjugates are merely slow-release storage forms of IAA.

Oetiker, J. H.; Aeschbacher, G.

1997-01-01

323

Identification of acetic acid bacteria isolated from Indonesian sources, especially of isolates classified in the genus Gluconobacter.  

PubMed

Sixty-four strains of acetic acid bacteria were isolated from Indonesian sources such as fruits, flowers, and fermented foods by the enrichment culture at pH 3.5. Forty-five strains were routinely identified as Acetobacter strains because of their oxidation of acetate and lactate to carbon dioxide and water and their Q-9 isoprenolog, corresponding to 70% of all the 64 acetic acid bacteria isolated. Eight isolates were identified as Gluconacetobacter strains because of their oxidation of acetate and lactate and their Q-10 isoprenolog, occupying 13% of all the isolates. The remaining 11 isolates, accommodated in the genus Gluconobacter because of no oxidation of acetate and lactate and because of their Q-10 isoprenolog, accounted for 17% of all the isolates. They were divided into two groups based on DNA base compositions. One comprised the seven isolates, which had high G1C contents of DNA ranging from 60.3 to 63.5 mol% and of which DNAs hybridized with that of the type strain of Gluconobacter oxydans at values of 64-94% of DNA relatedness. The other comprised the remaining four isolates, which had low G+C contents of DNA ranging from 57.5 to 57.7 mol% and of which DNAs hybridized with that of the type strain of Gluconobacter frateurii at values of 63-77% of DNA relatedness. The high values of DNA relatedness, 84 to 96%, were obtained between the type strains of Gluconobacter cerinus and Gluconobacter asaii. PMID:12501398

Yamada, Yuzo; Hosono, Reiko; Lisdyanti, Puspita; Widyastuti, Yantyati; Saono, Susono; Uchimura, Tai; Komagata, Kazuo

1999-02-01

324

Contribution to the Study of exp 14 C-Acetate as the Precursor of Amino Acids in Detached Leaves of Coffee (Coffea Arabica Cv. Mundo Novo).  

National Technical Information Service (NTIS)

Carbon-14 labelled acetates were used as the precursors of amino acids in leaves of coffee (Coffea arabica cv Mundo Novo). Leaves with the labelled acetates were incubated and released CO sub 2 was retained in paper discs with hiamine for further radioact...

O. G. Brasil

1975-01-01

325

Selective optimization in thermophilic acidogenesis of cheese-whey wastewater to acetic and butyric acids: partial acidification and methanation.  

PubMed

For partial acidogenesis of cheese-whey wastewater, a set of experiments were carried out to produce short-chain volatile fatty acids (VFA) in laboratory-scale continuously stirred tank reactors (CSTR). The maximum rate of acetic and butyric acid production associated with simultaneous changes in hydraulic retention time (HRT), pH, and temperature was investigated, in which the degree of acidification of the whey to the short-chain VFAs was less than 20% of the influent chemical oxygen demand (COD) concentration. Response surface methodology was successfully applied to determine the optimum physiological conditions where the maximum rates of acetic and butyric acid production occurred. These were 0.40-day HRT, pH 6.0 at 54.1 degrees C and 0.22-day HRT, pH 6.5 at 51.9 degrees C, respectively. The optimum conditions for acetic acid production were selected for partial acidification of cheese-whey wastewater because of a higher rate in combined productions of acetic and butyric acids than that at optimum conditions for butyric acid production. A thermophilic two-phase process with the partial acidification followed by a methanation step was operated. Performance of the two-phase process was compared to the single-phase anaerobic system. The two-phase process clearly showed a better performance in management of cheese-whey wastewater over the single-phase system. Maximum rate of COD removal and the rate of methane production in the two-phase process were, respectively, 116% and 43% higher than those of the single-phase system. PMID:12727259

Yang, Keunyoung; Yu, Youngseob; Hwang, Seokhwan

2003-05-01

326

Biosynthesis of indole-3-acetic acid in tomato shoots: Measurement, mass-spectral identification and incorporation of ?2 H from ?2 H 2 O into indole-3-acetic acid, d- and l-tryptophan, indole-3-pyruvate and tryptamine  

Microsoft Academic Search

Indole-3-acetic acid (IAA) and its putative precursors, l- and d-tryptophan, indole-3-pyruvate, and tryptamine were isolated from tomato (Lycopersicon esculentum (L.) Mill.) shoots, identified by mass spectrometry, and measured using capillary gas chromatography with an electron capture detector and radioactive internal standards. Average amounts present were 7.9ng · (g FW)--1 IAA, 5.7ng · (g FW)--1 indole-3-pyruvate, 132 ng · (g FW)--1

Terrence P. Cooney; Heather M. Nonhebel

1991-01-01

327

Inhibitory Effect of Curcumin, Chlorogenic Acid, Caffeic Acid, and Ferulic Acid on Tumor Promotion in Mouse Skin by 12-O-Tetradecanoylphorbol-13-acetate  

Microsoft Academic Search

The effects of topically applied curcumin, chlorogenic acid, caffeic acid, and ferulic acid on 12-O-tetradecanoylphorbol-13-acetate (TPA)- induced epidermal ornithine decarboxylase activity, epidermal DNA syn thesis, and the promotion of skin tumors were evaluated in female CD-I mice. Topical application of 0.5, 1, 3, or 10 iano\\\\ of curcumin inhibited by 31, 46, 84, or 98%, respectively, the induction of epidermal

Mou-Tuan Huang; Robert C. Smart; Ching-Quo Wong; Allan H. Conney

328

Location of Transported Auxin in Etiolated Maize Shoots Using 5-Azidoindole-3-Acetic Acid 1  

PubMed Central

A study was undertaken using the photoaffinity labeling agent, tritiated 5-azidoindole-3-acetic acid ([3H],5-N3IAA), to identify cells in the etiolated maize (Zea mays L.) shoot which transport auxin. Transport of [3H],5-N3IAA was shown to be polar, inhibited by 2,3,5-triiodobenzoic acid (TIBA) and essentially freely mobile. There was no detectable radiodecomposition of [3H],5-N3IAA within tissue kept in darkness for 4 hours. Shoot tissue which had taken up [3H],5-N3IAA was irradiated with ultraviolet light to covalently fix the photoaffinity labeling agent within cells that contained it at the time of photolysis. Subsequent microautoradiography showed that all cells contained radioactivity; however, the amount of radioactivity varied among different cell types. Epidermal cells contained the most radioactivity per area, approximately twofold more than other cells. Parenchyma cells in the mature stelar region contained the next largest amount and cortical cells, sieve tube cells, tracheary cells, and all cells in the leaf base contained the least amount of the radioactive label. Two observations suggest that the auxin within the epidermal cells is transported in a polar manner: (a) the amount of auxin in the epidermal cells is greatly reduced in the presence of TIBA, and (b) auxin accumulates on the apical side of a wound in the epidermis and is absent on the basal side. While these results indicate that auxin in the epidermis is polarly transported, this tissue cannot be the only pathway since the epidermis is only a small fraction of the shoot volume. The greater than twofold difference between the concentration of auxin in the epidermal and subtending cells demonstrates that physiological differences in the concentration of auxin can occur between adjacent cells. Images Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Jones, Alan M.

1990-01-01

329

Azospirillum brasilense Produces the Auxin-Like Phenylacetic Acid by Using the Key Enzyme for Indole-3-Acetic Acid Biosynthesis  

PubMed Central

An antimicrobial compound was isolated from Azospirillum brasilense culture extracts by high-performance liquid chromatography and further identified by gas chromatography-mass spectrometry as the auxin-like molecule, phenylacetic acid (PAA). PAA synthesis was found to be mediated by the indole-3-pyruvate decarboxylase, previously identified as a key enzyme in indole-3-acetic acid (IAA) production in A. brasilense. In minimal growth medium, PAA biosynthesis by A. brasilense was only observed in the presence of phenylalanine (or precursors thereof). This observation suggests deamination of phenylalanine, decarboxylation of phenylpyruvate, and subsequent oxidation of phenylacetaldehyde as the most likely pathway for PAA synthesis. Expression analysis revealed that transcription of the ipdC gene is upregulated by PAA, as was previously described for IAA and synthetic auxins, indicating a positive feedback regulation. The synthesis of PAA by A. brasilense is discussed in relation to previously reported biocontrol properties of A. brasilense.

Somers, E.; Ptacek, D.; Gysegom, P.; Srinivasan, M.; Vanderleyden, J.

2005-01-01

330

Self-association of acetic acid in dilute deuterated chloroform. Wide-range spectral reconstructions and analysis using FTIR spectroscopy, BTEM, and DFT.  

PubMed

The binary solution of acetic acid in CDCl(3) was studied at room pressure on the interval T = 293-313 K with a series of acetic acid concentrations up to 0.16 M. In-situ Fourier transform infrared (FTIR) spectroscopy measurements on the interval of 400-3800 cm(-1) were utilized as the analytical method to monitor the spectral changes due to self-association of acetic acid. The band-target entropy minimization (BTEM) algorithm was employed to reconstruct the underlying pure component spectra. Analysis successfully provided two major spectral estimates of acetic acid, namely, the monomer (primarily in the form of monomer-CDCl(3) complex) and the centrosymmetric cyclic dimer. In addition, analysis provided one minor spectral estimate containing signals from both noncyclic dimers and higher aggregates. Also, spectral estimates were obtained for phosgene and water which were present at trace levels even though considerable precaution was taken to conduct the experiments under anhydrous and anaerobic conditions. Density functional theory (DFT) calculation was performed to assign the acetic acid structures corresponding to the BTEM spectral estimates. Since the structure of dilute acetic acid has been the subject of numerous studies, the present investigation helps to resolve some issues concerning the speciation of acetic acid at low concentrations in low polarity solvents. In particular, the present study provides for the first time, wide-range spectral reconstructions of the species present. PMID:21043480

Tjahjono, Martin; Cheng, Shuying; Li, Chuanzhao; Garland, Marc

2010-11-25

331

Recovery of acetic acid from pre-hydrolysis liquor of hardwood kraft-based dissolving pulp production process by reactive extraction with triisooctylamine.  

PubMed

Acetic acid was one of the main compositions of the pre-hydrolysis liquor (PHL), which was recovered by reactive extraction with triisooctylamine (TIOA) diluted with decanol. Dilution of TIOA played an important role in extracting acetic acid from the PHL. The recovery of acetic acid from the PHL by TIOA was increased from 10.34% to 66.60% with the dilution of TIOA to 20% by decanol at the HAc to TIOA molar ratio of 1, consequently, the equilibrium distribution coefficient KD increased. The effects of time, temperature and pH on the extraction process were also studied. The extraction process was very fast. The acetic acid extraction decreased from 65.13% to 57.34% with the rise of temperature to 50°C from 20°C. A higher pH increased the dissociation of acetic acid, as a result, decreased acetic acid extraction. The hemicelluloses in the PHL were unaffected on the extraction process of acetic acid. PMID:23619137

Yang, G; Jahan, M Sarwar; Ahsan, Laboni; Zheng, Linqiang; Ni, Yonghao

2013-06-01

332

Spectrophotometric determination of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid in pure form and in pharmaceuticals  

NASA Astrophysics Data System (ADS)

A new sensitive and selective spectrophotometric method has been developed for the determination of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid in pharmaceuticals in the presence of nicotinic acid. The method is based on the reaction of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid with 1,3,3-trimethyl-5-phenyl-2-[3-(1,3,3-trimethyl-1,3-dihydro-indol-2-ylidene)-propenyl]-3 H-indolium chloride (PIC) followed by the extraction of the formed ion associate into toluene and spectrophotometric detection at 581 nm. Appropriate experimental conditions were found to be pH 7.8-9.8 and 3.6 × 10 -4 mol L -1 of PIC. The molar absorptivity is 5.0 × 10 -4 L mol -1 cm -1. The absorbance obeys Beer's law in the range 0.61-12.60 ?g mL -1 of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid, and the detection limit calculated from a blank test was 0.20 ?g mL -1.

Bazel, Yaroslav; Hunka, Iryna; Kormosh, Zholt; Andruch, Vasil

2009-12-01

333

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

334

FT-IR and Raman spectra vibrational assignments and density functional calculations of 1-naphthyl acetic acid  

NASA Astrophysics Data System (ADS)

This work deals with the vibrational spectroscopy of 1-naphthyl acetic acid. The molecular vibrations of 1-naphthyl acetic acid (NAA) is investigated in polycrystalline sample, at room temperature, by Fourier transform infrared (FT-IR) and FT-Raman spectroscopy. In parallel, ab initio and various density functional (DFT) methods were used to determine the geometrical, energetic and vibrational characteristics of NAA. On the basis of B3LYP/6-311 + G** method and basis set combinations, a normal mode analysis was performed to assign the various fundamental frequencies according to the total energy distribution (TED). Simulation of infrared and Raman spectra, utilizing the results of these calculations led to excellent overall agreement with observed spectral patterns by refinement of scale factors.

Krishnakumar, V.; Mathammal, R.; Muthunatesan, S.

2008-06-01

335

Myo-inositol esters of indole-3-acetic acid are endogenous components of Zea mays L. shoot tissue  

NASA Technical Reports Server (NTRS)

Indole-3-acetyl-myo-inositol esters have been demonstrated to be endogenous components of etiolated Zea mays shoots tissue. This was accomplished by comparison of the putative compounds with authentic, synthetic esters. The properties compared were liquid and gas-liquid chromatographic retention times and the 70-ev mass spectral fragmentation pattern of the pentaacetyl derivative. The amount of indole-3-acetyl-myo-inositol esters in the shoots was determined to be 74 nanomoles per kilogram fresh weight as measured by isotope dilution, accounting for 19% of the ester indole-3-acetic acid of the shoot. This work is the first characterization of an ester conjugate of indole-3-acetate acid from vegetative shoot tissue using multiple chromatographic properties and mass spectral identification. The kernel and the seedling shoot both contain indole-3-acetyl-myo-inositol esters, and these esters comprise approximately the same percentage of the total ester content of the kernel and of the shoot.

Chisnell, J. R.

1984-01-01

336

Validation of 7-keto-8-aminopelargonic acid synthase as a potential herbicide target with lead compound triphenyltin acetate  

Microsoft Academic Search

The validation of potential herbicide target, 7-keto-8-aminopelargonic acid synthase (KAPAS) in the early step of biotin biosynthesis pathway, was performed in vitro and in vivo with lead chemical triphenyltin acetate (TPTA). KAPAS activity was completely inhibited by TPTA with an IC50 of 19.85?M. 40-day-old Arabidopsis thaliana plants were killed with foliar treatment of 125gha?1 TPTA under the greenhouse conditions. The

In-Taek Hwang; Jung-Sup Choi; Ha-Young Song; Soo-Jin Cho; Hee-Kyung Lim; No-Joong Park; Dong-Hee Lee

2010-01-01

337

Studies on the transformation of rat embryo cells of low passage by carcinogenic fluorenylhydroxamic acids and their acetate esters  

Microsoft Academic Search

Summary  Rat embryo cells of low passage subjected to a single treatment with certain carcinogenic fluorenylhydroxamic acids and their\\u000a respective acetate esters showed signs of transformation in vitro, such as changes in phenotype, growth in soft agar and agglutination\\u000a with concanavalin. A. In addition, certain changes in karyotype and loss of diploidy were observed. There was no evidence,\\u000a either by electron

H. Kurzepa; H. R. Gutmann; D. Malejka-Giganti; A. Krauss; J. Cervenka; G. J. Vosika; R. E. Rydell

1978-01-01

338

Functional genomic analysis of the AUXIN\\/INDOLE3ACETIC ACID gene family members in Arabidopsis thaliana  

Microsoft Academic Search

Auxin regulates various aspects of plant growth and development. The AUXIN\\/INDOLE-3-ACETIC ACID (Aux\\/IAA) genes encode short-lived transcriptional repressors that are targeted by the TRANSPORT INHIBITOR RESPONSE1\\/AUXIN RECEPTOR F-BOX proteins. The Aux\\/IAA proteins regulate auxin-mediated gene expression by interacting with members of the AUXIN RESPONSE FACTOR protein family. Aux\\/IAA function is poorly understood; herein, we report the identification and characterization of

Paul J. Overvoorde; Yoko Okushima; Jose M. Alonso

2005-01-01

339

Electrochemical study of carbon steel corrosion in buffered acetic acid solutions with chlorides and H 2S  

Microsoft Academic Search

In this work, the corrosion behavior of SAE 1018 carbon steel in buffered acetic acid (HAc) solutions containing chlorides, with and without H2S, was studied. Polarization curves obtained by different electrochemical techniques, indicate negligible modification of anodic slopes when adding H2S; however, the cathodic branch is more sensitive showing an accelerated reduction reaction in the presence of H2S. Interface characterization

M. A. Veloz; I. González

2002-01-01

340

Acetic acid lontophoresis and ultrasound for the treatment of calcifying tendinitis of the shoulder: A randomized control trial  

Microsoft Academic Search

Objective: To assess the effects of acetic acid iontophoresis (AAI) and ultrasound on calcifying tendinitis of the shoulder, and to determine the relation between changes in the radiological measures of calcium deposit (CD) and shoulder function.Design: Randomized control trial.Setting: General community, private practice.Patients: Twenty-two adults (7 men, 15 women) with a calcifying tendinitis of the shoulder, without associated conditions, stratified

Marc Perron; Francine Malouin

1997-01-01

341

Flavone8Acetic Acid (Flavonoid) Profoundly Reduces Platelet-Dependent Thrombosis and Vasoconstriction After Deep Arterial Injury In Vivo  

Microsoft Academic Search

Background—Flavone-8-acetic acid (FAA; (Flavonoid)), an adjuvant antitumor drug, inhibits ristocetin-induced aggre- gation of human platelets. The effect of FAA on platelet-dependent thrombosis was studied in vivo in the porcine carotid artery after deep arterial injury by balloon angioplasty. Methods and Results— 111In-labeled autologous platelet and 125I-labeled porcine fibrin(ogen) deposition, and the incidence of macroscopic mural thrombosis onto deeply injured artery

Jozef S. Mruk; Mark W. I. Webster; Magda Heras; Joel M. Reid; Diane E. Grill; James H. Chesebro

342

Acetate oxidation to CO 2 in anaerobic bacteria via a novel pathway not involving reactions of the citric acid cycle  

Microsoft Academic Search

In several sulfate-reducing bacteria capable of complete oxidation of acetate (or acetyl CoA), the citric acid cycle is not operative. No 2-oxoglutarate dehydrogenase activity was found in these organisms, and the labelling pattern of oxaloacetate excludes its synthesis via 2-oxo-glutarate. These sulfate-reducers contained, however, high activities of the enzymes carbon monoxide dehydrogenase and formate dehydrogenase and catalyzed an isotope exchange

Rolf Schauder; Bernhard Eikmanns; Rudolf K. Thauer; Fritz Widdel; Georg Fuchs

1986-01-01

343

Microbicidal Action of Indole3Acetic Acid Combined with Horseradish Peroxidase on Prototheca   zopfii from Bovine Mastitis  

Microsoft Academic Search

We investigated the toxic effect of indole-3-acetic acid (IAA) combined with horseradish peroxidase (HRP) on Prototheca zopfii from bovine mastitis. P. zopfii isolates were identified and characterized by morpho-physiological parameters; presences of P. zopfii genotype 2 were also investigated. Subsequently, P. zopfii was incubated in the absence (control) or presence of IAA\\/HRP and examined for: (i) cell viability; (ii) colonies number\\u000a formation; (iii)

Luciane T. Cunha; Silvana M. P. Pugine; Marcia R. M. Silva; Ernane J. X. Costa; Mariza Pires De Melo

2010-01-01

344

Stability of the Acetic Acid-Induced Bladder Irritation Model in Alpha Chloralose-Anesthetized Female Cats  

PubMed Central

Time- and vehicle-related variability of bladder and urethral rhabdosphincter (URS) activity as well as cardiorespiratory and blood chemistry values were examined in the acetic acid-induced bladder irritation model in ?-chloralose-anesthetized female cats. Additionally, bladder and urethra were evaluated histologically using Mason trichrome and toluidine blue staining. Urodynamic, cardiovascular and respiratory parameters were collected during intravesical saline infusion followed by acetic acid (0.5%) to irritate the bladder. One hour after starting acetic acid infusion, a protocol consisting of a cystometrogram, continuous infusion-induced rhythmic voiding contractions, and a 5 min “quiet period” (bladder emptied without infusion) was precisely repeated every 30 minutes. Administration of vehicle (saline i.v.) occurred 15 minutes after starting each of the first 7 cystometrograms and duloxetine (1mg/kg i.v.) after the 8th. Acetic acid infusion into the bladder increased URS-EMG activity, bladder contraction frequency, and decreased contraction amplitude and capacity, compared to saline. Bladder activity and URS activity stabilized within 1 and 2 hours, respectively. Duloxetine administration significantly decreased bladder contraction frequency and increased URS-EMG activity to levels similar to previous reports. Cardiorespiratory parameters and blood gas levels remained consistent throughout the experiment. The epithelium of the bladder and urethra were greatly damaged and edema and infiltration of neutrophils in the lamina propria of urethra were observed. These data provide an ample evaluation of the health of the animals, stability of voiding function and appropriateness of the model for testing drugs designed to evaluate lower urinary tract as well as cardiovascular and respiratory systems function.

Kullmann, F. Aura; Wells, Grace I.; Langdale, Christopher L.; Zheng, Jihong; Thor, Karl B.

2013-01-01

345

The urinary ratio of 5-hydroxytryptophol to 5-hydroxyindole-3-acetic acid in surgical patients with chronic alcohol misuse.  

PubMed

The urinary ratio of 5-hydroxytryptophol to 5-hydroxyindole-3-acetic acid was reported to be elevated for a period of up to 22 h following acute alcohol ingestion. Therefore, the ratio could detect continuous alcohol consumption, in what was considered to be a high-risk surgical group, on the evening prior to surgery. The aim of this study was to determine the preoperative ratio of 5-hydroxytryptophol to 5-hydroxyindole-3-acetic acid in patients with continuous preoperative alcohol misuse. Forty-two patients participated in this institutionally approved study, once their written informed consent had been obtained. Chronic alcoholics were defined by meeting the criteria of the Diagnostic and Statistical Manual of Mental Disorders criteria and an ethanol consumption > or =60 g/day. The urine samples were taken preoperatively and determined by means of gas chromatography-mass spectrometry and high performance liquid chromatography. The urinary ratio of 5-hydroxytryptophol to 5-hydroxyindole-3-acetic acid was significantly increased in chronic alcoholics. The ICU stay of these patients was significantly prolonged due to an increased incidence of pneumonia and sepsis. Five chronic alcoholics died, whereas no deaths occurred in the nonalcoholic group (p = 0.05). As the measurement of the urinary ratio of 5-hydroxy-tryptophol to 5-hydroxyindole-3-acetic acid could detect alcohol consumption immediately prior to operation, this marker could assist the carbohydrate-deficient transferrin in screening for patients with high-level dependency; these patients were considered to be at a high risk of developing intercurrent complications. PMID:9895033

Spies, C D; Herpell, J; Beck, O; Müller, C; Pragst, F; Borg, S; Helander, A

1999-01-01

346

Effect of acetic acid complex on physical properties of nanostructured spray deposited FeCdS 3 thin films  

Microsoft Academic Search

Spray pyrolysis method which is simple as well as economic was used for the preparation of ternary nanostructured FeCdS3 thin films onto glass substrates from ferric nitrate and cadmium chloride as Cd and Fe source and acetic acid as a complexing agent. The prepared films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption techniques. The

A. U. Ubale; S. G. Ibrahim

2011-01-01

347

Composite Ferric Oxyhydroxide-Containing Phases Formed in Neutral Aqueous Solutions of Tryptophan and Indole3Acetic Acid  

Microsoft Academic Search

Mössbauer, FTIR and XRD analyses showed that in aqueous medium in air in the presence of L-tryptophan (Trp) or indole-3-acetic acid (IAA) the ambient-temperature ageing of the precipitates formed from ferrous sulphate at pH7 gave composite phases with varying proportions of -FeOOH (a dominating crystalline phase), -FeOOH (both fine-grained, showing superparamagnetic behaviour at 298 K, and relatively better crystallized) and

A. A. Kamnev; E. Kuzmann; Yu. D. Perfiliev; A. Vértes; M. Risti?; S. Popovi?

2000-01-01

348

Enzymatic hydrolytic resolution of ( R, S)-tropic acid esters and ( R, S)-ethyl ?-methoxyphenyl acetate in biphasic media  

Microsoft Academic Search

A thermally stable esterase from Klebsiella oxytoca is explored as an excellent enantioselective biocatalyst (E>100) for the hydrolytic resolution of (R,S)-tropic acid esters and (R,S)-ethyl ?-methoxyphenyl acetate in biphasic media. An expanded Michaelis–Menten mechanism for the enzymatic acylation step is adopted for the kinetic analysis, where the structure–enantioselectivity correlations in terms of the logarithms of specificity constants varied with the

Pei-Yun Wang; Shau-Wei Tsai

2009-01-01

349

Effect of calcination temperature of Ni\\/?-Al2O3 catalyst on the steam reforming of acetic acid  

Microsoft Academic Search

Ni\\/?-Al2O3-550 and Ni\\/?-Al2O3-800 catalysts (calcined at 550°C and 800°C in the catalyst preparation) were prepared with a impregnation method. Steam reforming of acetic acid as a model compound of bio-oil for hydrogen production had been investigated on the catalysts. The fresh catalysts were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR-H2) and specific surface area analysis (BET). The spent

Lu An; Changqing Dong; Junjiao Zhang; Yongping Yang

2009-01-01

350

High Plasma 5-Hydroxyindole-3-Acetic Acid Concentrations in Subjects With Metabolic Syndrome  

PubMed Central

OBJECTIVE Serotonin mediates vasoconstriction and induces the activation of platelets, which may promote atherosclerosis. The aim of this study was to investigate whether plasma 5-hydroxyindole-3-acetic acid (5-HIAA; a derivative end product of serotonin) concentrations are high in subjects with metabolic syndrome (MetS) and to investigate the relationship between plasma 5-HIAA concentrations and clinical and biochemical metabolic parameters. RESEARCH DESIGN AND METHODS Plasma 5-HIAA concentrations were measured in 311 subjects (152 men and 159 women) recruited from the Oike Clinic, which provides regular health check-ups for employees. We evaluated the relationship between plasma 5-HIAA concentrations and clinical and biochemical metabolic parameters, including waist circumference, serum lipid concentrations, fasting plasma glucose, or blood pressure. RESULTS Plasma 5-HIAA concentrations were higher in subjects with MetS than in those without, in both men (6.5 ± 4.4 vs. 4.9 ± 1.3 ng/mL, P < 0.005) and women (7.9 ± 6.5 vs. 5.2 ± 1.6 ng/mL, P < 0.005). In men, fasting plasma glucose (r = 0.197, P = 0.0146) was positively correlated, whereas HDL cholesterol (r = ?0.217, P = 0.0071) was negatively correlated, with logarithmic (log) (plasma 5-HIAA concentrations). In women, triglycerides (r = 0.252, P = 0.0013) and fasting plasma glucose (r = 0.344, P < 0.0001) were positively correlated, whereas HDL cholesterol (r = ?0.328, P < 0.0001) was negatively correlated, with log (5-HIAA concentrations). Furthermore, log (plasma 5-HIAA concentrations) were higher in subjects with more components of MetS. CONCLUSIONS Plasma 5-HIAA concentrations are high in subjects with MetS, suggesting the potential importance of serotonin in the development of cardiovascular disease in MetS.

Fukui, Michiaki; Tanaka, Muhei; Toda, Hitoshi; Asano, Mai; Yamazaki, Masahiro; Hasegawa, Goji; Imai, Saeko; Nakamura, Naoto

2012-01-01

351

Correlation between urinary 2-methoxy acetic acid and exposure of 2- methoxy ethanol  

PubMed Central

OBJECTIVES: To examine the correlation between airborne 2-methoxy ethanol (ME) exposures and the urinary 2-methoxy acetic acid (MAA) and to recommend a biological exposure index (BEI) for ME. METHODS: 8 Hour time weighted average (TWA) personal breathing zone samples and urine samples before and after the shift were collected from Monday to Saturday for 27 workers exposed to ME and on Friday for 30 control workers. RESULTS: No correlation was found between airborne exposure to ME and urinary MAA for nine special operation workers due to the use of personal protective equipment. For 18 regular operation workers, a significant correlation (r = 0.702, p = 0.001) was found between urinary MAA (mg/g creatinine) on Friday at the end of the shift and the weekly mean exposures of ME in a 5 day working week. The proposed BEI, which corresponds to exposure for 5 days and 8 hours a day to 5 ppm, extrapolated from the regression equation is 40 mg MAA/g creatinine. A significant correlation was also found between the weekly increase of urinary MAA (Friday after the shift minus Monday before the shift) and the weekly mean exposures of ME (r = 0.741). The recommended value of the weekly increase of urinary MAA for 5 days repeated exposures of 5 ppm ME is 20 mg/g creatinine. No urinary MAA was detected in workers in the non-exposed control group. CONCLUSIONS: The Friday urinary MAA after the shift or the weekly increase of urinary MAA is a specific and a good biomarker of weekly exposure to ME.  

Shih, T. S.; Liou, S. H.; Chen, C. Y.; Chou, J. S.

1999-01-01

352

Oleanolic acid acetate inhibits atopic dermatitis and allergic contact dermatitis in a murine model.  

PubMed

Atopic dermatitis (AD) and allergic contact dermatitis (ACD) are common allergic and inflammatory skin diseases caused by a combination of eczema, scratching, pruritus, and cutaneous sensitization with allergens. This paper examines whether oleanolic acid acetate (OAA) modulates AD and ACD symptoms by using an existing AD model based on the repeated local exposure of mite extract (Dermatophagoides farinae extract, DFE) and 2,4-dinitrochlorobenzene to the ears of BALB/c mice. In addition, the paper uses a 2,4-dinitrofluorobenzene-sensitized local lymph node assay (LLNA) for the ACD model. The oral administration of OAA over a four-week period attenuated AD symptoms in terms of decreased skin lesions, epidermal thickness, the infiltration of immune cells (CD4? cells, eosinophils, and mast cells), and serum IgE, IgG2a, and histamine levels. The gene expression of Th1, Th2, Th17, and Th22 cytokines was reduced by OAA in the lymph node and ear tissue, and the LLNA verified that OAA suppressed ACD. The oral administration of OAA over a three-day period attenuated ACD symptoms in terms of ear thickness, lymphocyte proliferation, and serum IgG2a levels. The gene expression of Th1, Th2, and Th17 cytokines was reduced by OAA in the thymus and ear tissue. Finally, to define the underlying mechanism, this paper uses a TNF-?/IFN-?-activated human keratinocyte (HaCaT) model. OAA inhibited the expression of cytokines and chemokines through the downregulation of NF-?B and MAPKs in HaCaT cells. Taken together, the results indicate that OAA inhibited AD and ACD symptoms, suggesting that OAA may be effective in treating allergic skin disorders. PMID:23499868

Choi, Jin Kyeong; Oh, Hyun-Mee; Lee, Soyoung; Park, Jin-Woo; Khang, Dongwoo; Lee, Seung Woong; Lee, Woo Song; Rho, Mun-Chual; Kim, Sang-Hyun

2013-05-15

353

Dietary supplementation with tributyrin alleviates intestinal injury in piglets challenged with intrarectal administration of acetic acid.  

PubMed

Tributyrin (TBU) is a good dietary source of butyrate and has beneficial effects on the maintenance of normal intestinal morphology. The present study tested the hypothesis that dietary TBU supplementation could alleviate intestinal injury in the acetic acid (ACA)-induced porcine model of colitis. A total of eighteen piglets (25 d old) were randomly allocated to one of three treatment groups (control, ACA and TBU). The control and ACA groups were fed a basal diet and the TBU group was fed the basal diet supplemented with 0·1 % TBU. On day 15 of the trial, under anaesthesia, a soft catheter was inserted into the rectum of piglets (20-25 cm from the anus), followed by administration of either saline (control group) or ACA (10 ml of 10 % ACA solution for ACA and TBU groups). On day 22 of the trial, after venous blood samples were collected, piglets were killed to obtain mid-ileum and mid-colon mucosae. Compared with the control group, the ACA group exhibited an increase (P< 0·05) in lymphocyte counts, creatinine, PGE2, and malondialdehyde concentrations and diamine oxidase and inducible NO synthase activities in the plasma and lymphocyte density in the colon and a decrease in insulin concentrations and glutathione peroxidase activity, ileal villus height:crypt depth ratios and goblet cell numbers in the colon. These adverse effects of ACA were attenuated by TBU supplementation. Moreover, TBU prevented the ACA-induced increase in caspase-3 levels while enhancing claudin-1 protein and epidermal growth factor receptor (EGFR) mRNA expression in the colonic mucosa. Collectively, these results indicate that dietary supplementation with 0·1 % TBU alleviates ACA-induced intestinal injury possibly by inhibiting apoptosis, promoting tight-junction formation and activating EGFR signalling. PMID:24506942

Hou, Yongqing; Wang, Lei; Yi, Dan; Ding, Binying; Chen, Xing; Wang, Qingjing; Zhu, Huiling; Liu, Yulan; Yin, Yulong; Gong, Joshua; Wu, Guoyao

2014-05-28

354

Contribution of Indole-3-Acetic Acid Production to the Epiphytic Fitness of Erwinia herbicola  

PubMed Central

Erwinia herbicola 299R produces large quantities of indole-3-acetic acid (IAA) in culture media supplemented with l-tryptophan. To assess the contribution of IAA production to epiphytic fitness, the population dynamics of the wild-type strain and an IAA-deficient mutant of this strain on leaves were studied. Strain 299XYLE, an isogenic IAA-deficient mutant of strain 299R, was constructed by insertional interruption of the indolepyruvate decarboxylase gene of strain 299R with the xylE gene, which encodes a 2,3-catechol dioxygenase from Pseudomonas putida mt-2. The xylE gene provided a useful marker for monitoring populations of the IAA-deficient mutant strain in mixed populations with the parental strain in ecological studies. A root bioassay for IAA, in which strain 299XYLE inhibited significantly less root elongation than strain 299R, provided evidence that E. herbicola produces IAA on plant surfaces in amounts sufficient to affect the physiology of its host and that IAA production in strain 299R is not solely an in vitro phenomenon. The epiphytic fitness of strains 299R and 299XYLE was evaluated in greenhouse and field studies by analysis of changes in the ratio of the population sizes of these two strains after inoculation as mixtures onto plants. Populations of the parental strain increased to approximately twice those of the IAA-deficient mutant strain after coinoculation in a proportion of 1:1 onto bean plants in the greenhouse and onto pear flowers in field studies. In all experiments, the ratio of the population sizes of strain 299R and 299XYLE increased during periods of active growth on plant tissue but not when population sizes were not increasing with time.

Brandl, M. T.; Lindow, S. E.

1998-01-01

355

Double proton transfer in the complex of acetic acid with methanol: Theory versus experiment  

NASA Astrophysics Data System (ADS)

To test the approximate instanton approach to intermolecular proton-transfer dynamics, we report multidimensional ab initio bimolecular rate constants of HH, HD, and DD exchange in the complex of acetic acid with methanol in tetrahydrofuran-d8, and compare them with the NMR (nuclear magnetic resonance) experiments of Gerritzen and Limbach. The bimolecular rate constants are evaluated as products of the exchange rates and the equilibrium rate constants of complex formation in solution. The two molecules form hydrogen-bond bridges and the exchange occurs via concerted transfer of two protons. The dynamics of this transfer is evaluated in the complete space of 36 vibrational degrees of freedom. The geometries of the two isolated molecules, the complex, and the transition states corresponding to double proton transfer are fully optimized at QCISD (quadratic configuration interaction including single and double substitutions) level of theory, and the normal-mode frequencies are calculated at MP2 (Møller-Plesset perturbation theory of second order) level with the 6-31G (d,p) basis set. The presence of the solvent is taken into account via single-point calculations over the gas phase geometries with the PCM (polarized continuum model). The proton exchange rate constants, calculated with the instanton method, show the effect of the structure and strength of the hydrogen bonds, reflected in the coupling between the tunneling motion and the other vibrations of the complex. Comparison with experiment, which shows substantial kinetic isotopic effects (KIE), indicates that tunneling prevails over classic exchange for the whole temperature range of observation. The unusual behavior of the experimental KIE upon single and double deuterium substitution is well reproduced and is related to the synchronicity of two-atom tunneling.

Fernández-Ramos, Antonio; Smedarchina, Zorka; Rodríguez-Otero, Jesús

2001-01-01

356

Evaluation of adsorption effects on measurements of ammonia, acetic acid, and methanol  

NASA Astrophysics Data System (ADS)

We examined how adsorption and desorption of gases from inlets and a cell could affect the accuracy of closed-cell FTIR measurements of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nitric oxide (NO), nitrogen dioxide (NO2), methanol (CH3OH), acetic acid (CH3COOH), and ammonia (NH3). When standards were delivered to the cell through a stainless steel inlet, temporarily reduced transmission was observed for CH3OH and NH3. However, a halocarbon wax coated inlet (normally used on the system) had excellent transmission (comparable to room temperature Teflon) for both CH3OH and NH3, even at temperatures as low as 5°C. Thus the wax is valuable for coating sampling system components that cannot be fashioned from Teflon. The instrument had a delayed response (˜10-40 s) for NH3 only, which was attributed to passivation of the Pyrex multipass cell. To determine sampling artifacts that could arise from the complex sample matrix presented by smoke, the closed-cell FTIR system was intercompared with an open-path FTIR system (which is immune to sampling artifacts) in well-mixed smoke. A similar cell passivation delay for NH3 was the only artifact found in this test. Overall, the results suggest that ˜10 s is sufficient to detect >80% of an NH3/CO ratio sampled by our fast-flow, closed-cell system. Longer sampling times or consecutive samples return better results. In field campaigns the closed-cell system sampling times were normally 10 to >100 s so NH3 was probably underestimated by 5-15%.

Yokelson, R. J.; Christian, T. J.; Bertschi, I. T.; Hao, W. M.

2003-10-01

357

Selective liquid chromatographic separation of yttrium from heavier rare earth elements using acetic acid as a novel eluent.  

PubMed

One of the major difficulties in the rare earth elements separation is purification of yttrium from heavy rare earth elements. Thus, an HPLC method using acetic acid as novel eluent was explored for selective separation of yttrium form the heavy rare earth elements. When acetic acid is used as a mobile phase yttrium eluted with the lighter lanthanides. This is contrary to its relative position amongst heavier lanthanides when eluents commonly used for separation of rare earth elements were employed. The shift in elution position of yttrium with acetic acid as eluent may reflect a relatively lower stability constant of the yttrium-AcOH complex (in the same order as for the lighter lanthanides) compared to the corresponding AcOH complexes with heavy lanthanides, enabling selective separation of yttrium from the latter. The method was successfully used for selective separation of yttrium in mixed rare earth sample containing about 80% of yttrium and about 20% of heavy rare earth oxides. Thus, the use of AcOH as eluent is an effective approach for separating and determining the trace amounts of heavy rare earth elements in large amounts of yttrium matrix. Separation was performed on C18 column by running appropriate elution programs. The effluent from the column was monitored with diode array detector at absorbance wavelength of 658nm after post column derivatization with Arsenazo III. PMID:23932372

Kifle, Dejene; Wibetoe, Grethe

2013-09-13

358

Effects of indole-3-acetic acid on Botrytis cinerea isolates obtained from potted plants.  

PubMed

We study the growth of different isolates of Botrytis cinerea collected from potted plants which were affected by Botrytis blight in southern Spain during recent years. These isolates, which show widely phenotypic differences when grown in vitro, are differentially affected by growth temperature, gibberellic acid applications and paclobutrazol, an efficient plant growth retardant and fungicide at the same time. In this work, we have evaluated the effect of the auxin indole-3-acetic acid (IAA) dose (0, 1, 10, and 100 mg/plate) on the growth of the collection of B. cinerea isolates obtained from the following potted plants: Cyclamen persicum, Hydrangea macrophylla, Lantona camara, and Lonicera japonica. B. cinerea produces indolacetic acid, but so far the precise biosynthetic pathway and some effects on this fungal species are still unclear, although recent studies have revealed an antifungal activity of IAA on several fungi, including B. cinerea isolated from harvested fruits. Mycelial growth curves and growth rates assessed from difference in colony areas during the both linear and deceleration phase, conidiation (measured as time of appearance), conidia length (microm), and sclerotia production (number/plate) were evaluated in the isolates, which were grown at 26 degrees C on Petri dishes containing potato dextrose agar for up to 35 days. Mycelial growth curves fitted a typical kinetic equation of fungi grown on solid media. B. cinerea isolates showed a high degree of variability in their growth kinetics, depending on the isolate and auxin dose. This plant growth substance delayed mycelial growth during the linear phase in an isolate-dependent manner, thus isolates from C. persicum, H. macrophylla and L. camara were more affected by IAA than L. japonica. On the other hand, 100 mg of IAA was the critical dose to significantly reduce the growth rate in all isolates and to promote brown-striped hyphae development, especially in isolate from C. persicum. 10 and 100 mg IAA delayed conidiation in isolates from H. macrophylla but scarcely effects were found in the conidia length. The sclerotia production process was blocked at IAA doses of 100 mg in isolates from L. camara and L. japonica, and was reduced in isolate from H. macrophylla. However, dose of 100 mg IAA had no effect on sclerotia production in isolate from C. persicum. It was concluded that the effect of IAA on B. cinerea growth depends on the isolate, thus isolates from H. macrophylla and L. camara were the most affected by IAA. B. cinerea reduced its development under IAA applications, depending on the isolate and dose. These results confirm those recently published on the inhibitory effect of IAA on Botrytris species growth. PMID:22702183

Martínez, J A; Valdés, R; Gómez-Bellot, M J; Bañón, S

2011-01-01

359

The Conjugated Auxin Indole-3-Acetic Acid-Aspartic Acid Promotes Plant Disease Development[C][W  

PubMed Central

Auxin is a pivotal plant hormone that regulates many aspects of plant growth and development. Auxin signaling is also known to promote plant disease caused by plant pathogens. However, the mechanism by which this hormone confers susceptibility to pathogens is not well understood. Here, we present evidence that fungal and bacterial plant pathogens hijack the host auxin metabolism in Arabidopsis thaliana, leading to the accumulation of a conjugated form of the hormone, indole-3-acetic acid (IAA)-Asp, to promote disease development. We also show that IAA-Asp increases pathogen progression in the plant by regulating the transcription of virulence genes. These data highlight a novel mechanism to promote plant susceptibility to pathogens through auxin conjugation.

Gonzalez-Lamothe, Rocio; El Oirdi, Mohamed; Brisson, Normand; Bouarab, Kamal

2012-01-01

360

Sol-gel process for preparation of YBa{sub 2}Cu{sub 4}O{sub 8} from acidic acetates/ammonia/ascorbic acid systems  

SciTech Connect

YBa{sub 2}Cu{sub 4}O{sub x} sols were prepared by addition of ammonia to acidic acetate solutions of Y{sup 3+}, Ba{sup 2+}, and Cu{sup 2+}. Ascorbic acid was added to part of the sol. The resultant sols were gelled to a shard or a coating by evaporation at 60 C. Addition of ethanol to the sols facilitated formation of gel coatings, fabricated by a dipping technique, on Ag or glass or substrates. At 100 C, gels formed in the presence of ascorbic acid were perfectly amorphous, in contrast to crystalline acetate gels. The quality of coatings prepared from ascorbate gels was superior to that of acetate gel coatings.

Deptula, A.; Lada, W.; Olczak, T. [Inst. of Nuclear Chemistry and Technology, Warsaw (Poland)] [Inst. of Nuclear Chemistry and Technology, Warsaw (Poland); Goretta, K.C. [Argonne National Lab., IL (United States). Energy Technology Div.] [Argonne National Lab., IL (United States). Energy Technology Div.; Bartolomeo, A.; Casadio, S. [C.R.E. Casaccia, Rome (Italy)] [C.R.E. Casaccia, Rome (Italy)

1997-03-01

361

Preparation of macroporous lime from natural lime by swelling method with acetic acid for high-temperature desulfurization  

SciTech Connect

To develop a highly active calcium oxide high-temperature desulfurization sorbent, a method of preparation of macroporous calcium oxides from lime was studied. This method is composed of two steps: swelling of the lime and calcination of the swelled sample. Swelling occurred when lime was exposed to the vapor of acetic acid. The swelling resulted from calcium acetate formation in the sample. The swelling rate was at a maximum in the presence of acetic acid and depressed by the presence of water vapor. The swelled sample was converted to macroporous calcium oxide by heating to 850 C. The reactivity of the macroporous calcium oxide for the removal of SO{sub 2} or H{sub 2}S in the presence of H{sub 2}O vapor was higher than that of the calcined raw limestone. In particular, its SO{sub 2} removal capacity and the oxidative character of CaS to CaSO{sub 4} and Cao were greatly improved by this swelling method. These characteristics were also compared with those of a sample prepared from limestone by this swelling method.

Sasaoka, Eiji; Sada, Norimasa; Uddin, M.A. [Okayama Univ. (Japan)] [Okayama Univ. (Japan)

1998-10-01

362

Salts of aliphatic carboxylic acids: Raman spectra and ion pairing in hydrothermal solutions containing sodium and calcium acetates  

Microsoft Academic Search

A 2.0 molal solution of sodium acetate and 0.1, 0.5, and 1.0 molal solutions of calcium acetate were investigated by Raman spectroscopy from 22 to 400°C at 1000 and 2000 bar. Experiments were performed in a special hydrothermal pressure vessel fitted with conical diamond windows. In the case of the sodium acetate solution, perturbations of the internal vibrational modes of

John D Frantz

2000-01-01

363

Lead Acetate, Teratology Study - Rabbits.  

National Technical Information Service (NTIS)

Three groups of 15 females rabbits were mated. Two groups were fed lead acetate in their diet at lead concentrations of 54.6 and 546 ppm from day 6 through day 16 of their gestation period. The third group of females and all males received the basal labor...

D. C. Jessup

1967-01-01

364

Neoasaia chiangmaiensis gen. nov., sp. nov., a novel osmotolerant acetic acid bacterium in the alpha-Proteobacteria.  

PubMed

An acetic acid bacterium, designated as isolate AC28(T), was isolated from a flower of red ginger (khing daeng in Thai; Alpinia purpurata) collected in Chiang Mai, Thailand, at pH 3.5 by use of a glucose/ethanol/acetic acid (0.3%, w/v) medium. A phylogenetic tree based on 16S rRNA gene sequences for 1,376 bases showed that isolate AC28(T) constituted a cluster along with the type strain of Kozakia baliensis. However, the isolate formed an independent cluster in a phylogenetic tree based on 16S-23S rDNA internal transcribed spacer (ITS) region sequences for 586 bases. Pair-wise sequence similarities of the isolate in 16S rRNA gene sequences for 1,457 bases were 93.0-88.3% to the type strains of Asaia, Kozakia, Swaminathania, Acetobacter, Gluconobacter, Gluconacetobacter, Acidomonas, and Saccharibacter species. Restriction analysis of 16S-23S rDNA ITS regions discriminated isolate AC28(T) from the type strains of Asaia and Kozakia species. Cells were non-motile. Colonies were pink, shiny, and smooth. The isolate produced acetic acid from ethanol. Oxidation of acetate and lactate was negative. The isolate grew on glutamate agar and mannitol agar. Growth was positive on 30% D-glucose (w/v) and in the presence of 0.35% acetic acid (w/v), but not in the presence of 1.0% KNO(3) (w/v). Ammoniac nitrogen was hardly assimilated on a glucose medium or a mannitol medium. Production of dihydroxyacetone from glycerol was weakly positive. The isolate did not produce a levan-like polysaccharide on a sucrose medium. Major isoprenoid quinone was Q-10. DNA base composition was 63.1 mol% G+C. On the basis of the results obtained, Neoasaia gen. nov. was proposed with Neoasaia chiangmaiensis sp. nov. The type strain was isolate AC28(T) (=BCC 15763(T) =NBRC 101099(T)). PMID:16314684

Yukphan, Pattaraporn; Malimas, Taweesak; Potacharoen, Wanchern; Tanasupawat, Somboon; Tanticharoen, Morakot; Yamada, Yuzo

2005-10-01

365

Recovering/concentrating of hemicellulosic sugars and acetic acid by nanofiltration and reverse osmosis from prehydrolysis liquor of kraft based hardwood dissolving pulp process.  

PubMed

This work investigated the feasibility of recovering and concentrating sugars and acetic acid (HAc) from prehydrolysis liquor (PHL) of the kraft-based dissolving pulp process prior to fermentation of hemicellulosic sugars, by the combination of activated carbon adsorption, nanofiltration (NF) and reverse osmosis (RO) processes. To reduce the fouling PHL was subjected to adsorption on activated carbon, then the treated PHL (TPHL) passed through a nanofiltration (NF DK) membrane to retain the sugars, and the permeate of acetic acid rich solution was passed through a reverse osmosis membrane (RO SG). It was found that for NF process sugars were concentrated from 48 to 227g/L at a volume reduction factor (VRF) of 5 while 80 to 90% of acetic acid was permeated. For the reverse osmosis process, 68% of acetic acid retention was achieved at pH 4.3 and 500 psi pressure and the HAc concentration increased from 10 to 50g/L. PMID:24434701

Ahsan, Laboni; Jahan, M Sarwar; Ni, Yonghao

2014-03-01

366

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

367

Conversions of methyl esters of (6-methyl-2-methylthio-4-pyrimidinyloxy)- and (3,4-dihydro-6-methyl-2-methylthio-4-oxo-3-pyrimidinyl)acetic acids  

Microsoft Academic Search

A study has been made of nucleophilic reactions (hydrolysis, hydrazinolysis, ammonolysis, reduction) and electrophilic reactions (bromination, nitration) of isomeric methyl esters of (6-methyl-2-methylthio-4-pyrimidinyloxy) acetic acid and (3,4-dihydro-6-methyl-2-methylthio-4-oxo-3-pyrimidinyl)acetic acid. Carboxyl-group derivatives and also derivatives with substituents in position 5 of the pyrimidine ring have been synthesized.

P. Vainilavichyus; V. Syadyaryavichyute; S. Motsishkite

1992-01-01

368

A 9-vinyladenine-based molecularly imprinted polymeric membrane for the efficient recognition of plant hormone 1H-indole-3-acetic acid  

Microsoft Academic Search

9-Vinyladenine was synthesized as a novel functional monomer for molecular imprinting techniques and its structure was established with elemental analysis and 1H NMR spectroscopy. The binding mechanism between this functional monomer 9-vinyladenine and the plant hormone 1H-indole-3-acetic acid in acetonitrile was studied with UV–vis spectrophotometry. Based on this study, using 1H-indole-3-acetic acid as a template molecule, a specific 9-vinyladenine-based molecularly

Changbao Chen; Yanjun Chen; Jie Zhou; Chunhui Wu

2006-01-01

369

Surface characterization of ethylene-vinyl acetate (EVA) and ethylene-acrylic acid (EAA) co-polymers using XPS and AFM  

Microsoft Academic Search

The air surfaces of ethylene-vinyl acetate (EVA) co-polymers with 9–70 wt% vinyl acetate (VA) and ethylene-acrylic acid (EAA) co-polymers with 3–20 wt% acrylic acid (AA) were studied using XPS at three take-off angles, representing three depths of penetration from 15–58 Å. The semi-crystalline EVA and EAA co-polymers with high wt% ethylene (9–27.5 wt% VA) had higher percentages of VA at

Ruth L. McEvoy; Sonja Krause; Peter Wu

1998-01-01

370

Effects of acetic acid injection and operating conditions on NO emission in a vortexing fluidized bed combustor using response surface methodology  

SciTech Connect

The effects of acetic acid injection and operating conditions on NO emission were investigated in a pilot scale vortexing fluidized bed combustor (VFBC), an integration of circular freeboard and a rectangular combustion chamber. Operating conditions, such as the stoichiometric oxygen in the combustion chamber, the bed temperature and the injecting location of acetic acid, were determined by means of response surface methodology (RSM), which enables the examination of parameters with a moderate number of experiments. In RSM, NO emission concentration after acetic acid injection and NO removal percentage at the exit of the VFBC are used as the objective function. The results show that the bed temperature has a more important effect on the NO emission than the injecting location of acetic acid and the stoichiometric oxygen in the combustion chamber. Meanwhile, the injecting location of acetic acid and the stoichiometric oxygen in the combustion chamber have a more important effect on the NO removal percentage than the bed temperature. NO emission can be decreased by injecting the acetic acid into the combustion chamber, and NO emission decreases with the height of the acetic acid injecting location above the distributor. On the other hand, NO removal percentage increases with the height of the acetic acid injecting location, and NO emission increases with the stoichiometric oxygen in the combustion chamber and the bed temperature. NO removal percentage increases with the stoichiometric oxygen, and increases first, then decreases with the bed temperature. Also, a higher NO removal percentage could be obtained at 850{sup o}C. 26 refs., 12 figs., 8 tabs.

Fuping Qian; Chiensong Chyang; Weishen Yen [Anhui University of Technology, Ma'anshan (China). School of Civil Engineering and Architecture

2009-07-15

371

Protective effects of N-acetylcysteine on acetic acid-induced colitis in a porcine model  

PubMed Central

Background Ulcerative colitis is a chronic inflammatory disease and involves multiple etiological factors. Acetic acid (AA)-induced colitis is a reproducible and simple model, sharing many characteristics with human colitis. N-acetylcysteine (NAC) has been widely used as an antioxidant in vivo and in vitro. NAC can affect several signaling pathways involving in apoptosis, angiogenesis, cell growth and arrest, redox-regulated gene expression, and inflammatory response. Therefore, NAC may not only protect against the direct injurious effects of oxidants, but also beneficially alter inflammatory events in colitis. This study was conducted to investigate whether NAC could alleviate the AA-induced colitis in a porcine model. Methods Weaned piglets were used to investigate the effects of NAC on AA-induced colitis. Severity of colitis was evaluated by colon histomorphology measurements, histopathology scores, tissue myeloperoxidase activity, as well as concentrations of malondialdehyde and pro-inflammatory mediators in the plasma and colon. The protective role of NAC was assessed by measurements of antioxidant status, growth modulator, cell apoptosis, and tight junction proteins. Abundances of caspase-3 and claudin-1 proteins in colonic mucosae were determined by the Western blot method. Epidermal growth factor receptor, amphiregulin, tumor necrosis factor-alpha (TNF-?), and toll-like receptor 4 (TLR4) mRNA levels in colonic mucosae were quantified using the real-time fluorescent quantitative PCR. Results Compared with the control group, AA treatment increased (P?

2013-01-01

372

GC-based Detection of Aldononitrile Acetate Derivatized Glucosamine and Muramic Acid for Microbial Residue Determination in Soil  

PubMed Central

Quantitative approaches to characterizing microorganisms are crucial for a broader understanding of the microbial status and function within ecosystems. Current strategies for microbial analysis include both traditional laboratory culture-dependent techniques and those based on direct extraction and determination of certain biomarkers1, 2. Few among the diversity of microbial species inhabiting soil can be cultured, so culture-dependent methods introduce significant biases, a limitation absent in biomarker analysis. The glucosamine, mannosamine, galactosamine and muramic acid have been well served as measures of both the living and dead microbial mass, of these the glucosamine (most abundant) and muramic acid (uniquely from bacterial cell) are most important constituents in the soil systems3, 4. However, the lack of knowledge on the analysis restricts the wide popularization among scientific peers. Among all existing analytical methods, derivatization to aldononitrile acetates followed by GC-based analysis has emerged as a good option with respect to optimally balancing precision, sensitivity, simplicity, good chromatographic separation, and stability upon sample storage5. Here, we present a detailed protocol for a reliable and relatively simple analysis of glucosamine and muramic acid from soil after their conversion to aldononitrile acetates. The protocol mainly comprises four steps: acid digestion, sample purification, derivatization and GC determination. The step-by-step procedure is modified according to former publications6, 7. In addition, we present a strategy to structurally validate the molecular ion of the derivative and its ion fragments formed upon electron ionization. We applied GC-EI-MS-SIM, LC-ESI-TOF-MS and isotopically labeled reagents to determine the molecular weight of aldononitrile acetate derivatized glucosamine and muramic acid; we used the mass shift of isotope-labeled derivatives in the ion spectrum to investigate ion fragments of each derivatives8. In addition to the theoretical elucidation, the validation of molecular ion of the derivative and its ion fragments will be useful to researchers using ?13C or ion fragments of these biomarkers in biogeochemical studies9, 10.

Liang, Chao; Read, Harry W.; Balser, Teri C.

2012-01-01

373

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

374

Protective Role of Omega-3 Polyunsaturated Fatty Acid against Lead Acetate-Induced Toxicity in Liver and Kidney of Female Rats  

PubMed Central

The present study was conducted to investigate the protective role of Omega-3 polyunsaturated fatty acids against lead acetate-induced toxicity in liver and kidney of female rats. Animals were divided into four equal groups; group 1 served as control while groups 2 and 3 were treated orally with Omega-3 fatty acids at doses of 125 and 260?mg/kg body weight, respectively, for 10 days. These groups were also injected with lead acetate (25?mg/kg body weight) during the last 5 days. Group 4 was treated only with lead acetate for 5 days and served as positive control group. Lead acetate increased oxidative stress through an elevation in MDA associated with depletion in antioxidant enzymes activities in the tissues. Moreover, the elevation of serum enzymes activities (ALT, AST, ALP, and LDH) and the levels of urea and creatinine were estimated but total proteins were decreased. Also, lead acetate-treatment induced hyperlipidemia via increasing of lipid profiles associated with decline in HDL-c level. Significant changes of Hb, PCV, RBCs, PLT, and WBCs in group 4 were recorded. The biochemical alterations of lead acetate were confirmed by histopathological changes and DNA damage. The administration of Omega-3 provided significant protection against lead acetate toxicity.

Abdou, Heba M.; Hassan, Mohamed A.

2014-01-01

375

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

376

Biofiltration of ethyl acetate and amyl acetate using a composite bead biofilter.  

PubMed

Biodegradation kinetic behaviors of ethyl acetate and amyl acetate in a composite bead biofilter were investigated. The composite bead was the spherical PVA/peat/KNO3/GAC composite bead which was prepared in our previous works. Both microbial growth rate and biochemical reaction rate were inhibited at higher inlet concentration. For the microbial growth process, the microbial growth rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The degree of inhibitive effect was almost the same for ethyl acetate and amyl acetate in this concentration range. The half-saturation constant Ks values of ethyl acetate and amyl acetate were 16.26 and 12.65ppm, respectively. The maximum reaction rate Vm values of ethyl acetate and amyl acetate were 4.08 and 3.53gCh(-1)kg(-1) packed material, respectively. Zero-order kinetic with the diffusion limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the biochemical reaction rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The inhibitive effect for ethyl acetate was more pronounced than that for AA in this concentration range. The maximum elimination capacity of ethyl acetate and amyl acetate were 82.3 and 37.93gCh(-1)m(-3) bed volume, respectively. Ethyl acetate degraded by microbial was easier than amyl acetate did. PMID:18445522

Chan, Wu-Chung; Su, Mei-Qi

2008-11-01

377

Ozone decomposition in aqueous acetate solutions  

SciTech Connect

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

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

1987-01-01

378

A high-throughput method for the quantitative analysis of indole-3-acetic acid and other auxins from plant tissue.  

PubMed

To investigate novel pathways involved in auxin biosynthesis, transport, metabolism, and response, we have developed a high-throughput screen for indole-3-acetic acid (IAA) levels. Historically, the quantitative analysis of IAA has been a cumbersome and time-consuming process that does not lend itself to the screening of large numbers of samples. The method described here can be performed with or without an automated liquid handler and involves purification solely by solid-phase extraction in a 96-well format, allowing the analysis of up to 96 samples per day. In preparation for quantitative analysis by selected ion monitoring-gas chromatography-mass spectrometry, the carboxylic acid moiety of IAA is derivatized by methylation. The derivatization of the IAA described here was also done in a 96-well format in which up to 96 samples can be methylated at once, minimizing the handling of the toxic reagent, diazomethane. To this end, we have designed a custom diazomethane generator that can safely withstand high flow and accommodate larger volumes. The method for IAA analysis is robust and accurate over a range of plant tissue weights and can be used to screen for and quantify other indolic auxins and compounds including indole-3-butyric acid, 4-chloro-indole-3-acetic acid, and indole-3-propionic acid. PMID:17889819

Barkawi, Lana S; Tam, Yuen-Yee; Tillman, Julie A; Pederson, Ben; Calio, Jessica; Al-Amier, Hussein; Emerick, Michael; Normanly, Jennifer; Cohen, Jerry D

2008-01-15

379

Simultaneous determination of furfural, acetic acid, and 5-hydroxymethylfurfural in corncob hydrolysates using liquid chromatography with ultraviolet detection.  

PubMed

A single-laboratory validation study was conducted using HPLC for detecting and quantifying acetic acid, furfural, and 5-hydroxymethylfurfural (HMF) in corncob hydrolysates. A pretreatment procedure using dilute sulfuric acid was optimized for corncob hydrolysis. The final hydrolysates were analyzed by HPLC using a C18 RP column with aqueous 0.01% (v/v) H2SO4-CH3OH (95 + 5) as the mobile phase at a flow rate of 1 mL/min. The wavelengths for detecting the three compounds were changed to their optimal UV detection wavelengths at the time of elution. The wavelength detection adjustments were as follow: 205 nm (0 to 4 min); 284 nm (4 to 7 min); and 276 nm (7 to 10 min). Separation was achieved with a chromatographic run time of 10 min. The calibration curves for the three compounds had correlation coefficients (r2) > or = 99.8%. The analytical range, as defined by the calibration curves, was 0.5-10 mg/L for acetic acid, 0.4-22 mg/L for furfural, and 0.1-18 mg/L for HMF. The LODs for acetic acid, furfural, and HMF were estimated to be 0.05, 0.03, and 0.02 mg/L, respectively; the LOQs were 0.196, 0.135, and 0.074 mg/L, respectively. The RSD values for the intraday precision study ranged from 0.31 to 2.22%, and from 0.57 to 2.43% for the interday study. The mean recovery rates in all compounds were between 100.08 and 101.49%. PMID:24645500

Dong, Bo-Yu; Chen, Ye-Fu; Zhao, Chang-Chun; Zhang, Shi-Jie; Guo, Xue-Wu; Xiao, Dong-Guang

2013-01-01

380

Expansins are involved in cell growth mediated by abscisic acid and indole-3-acetic acid under drought stress in wheat.  

PubMed

Expansin protein is a component of the cell wall generally accepted to be the key regulator of cell wall extension during plant growth. Plant hormones regulate expansin gene expression as well as plant growth during drought stress. However, the relationship between expansin and plant hormone is far from clear. Here, we studied the involvement of expansin in plant cell growth mediated by the hormones indole-3-acetic acid (IAA) and abscisic acid (ABA) under osmotic stress which was induced by polyethylene glycol (PEG)-6000. Wheat coleoptiles from a drought-resistant cultivar HF9703 and a drought-sensitive cultivar 921842 were used to evaluate cell growth and expansin activity. Osmotic stress induced the accumulation of ABA. ABA induced expansin activity mainly by enhancing expansin expression, since ABA induced cell wall basification via decreasing plasma membrane H(+)-ATPase activity, which was unfavorable for expansin activity. Although ABA induced expansin activity and cell wall extension, treatment with exogenous ABA and/or fluridone (FLU, an ABA inhibitor) suggested that ABA was involved in the coleoptile growth inhibition during osmotic stress. IAA application to detached coleoptiles also enhanced coleoptile growth and increased expansin activity, but unlike ABA, IAA-induced expansin activity was mainly due to the decrease of cell wall pH by increasing plasma membrane H(+)-ATPase activity. Compared with drought-sensitive cultivar, the drought-resistant cultivar could maintain greater expansin activity and cell wall extension, which was contributive to its resultant faster growth under water stress. PMID:22076248

Zhao, Mei-rong; Han, Yang-yang; Feng, Ya-nan; Li, Feng; Wang, Wei

2012-04-01

381

Studies on the growth and indole-3-acetic acid and abscisic acid content of Zea mays seedlings grown in microgravity  

NASA Technical Reports Server (NTRS)

Measurements were made of the fresh weight, dry weight, dry weight-fresh weight ratio, free and conjugated indole-3-acetic acid, and free and conjugated abscisic acid in seedlings of Zea mays grown in darkness in microgravity and on earth. Imbibition of the dry kernels was 17 h prior to launch. Growth was for 5 d at ambient orbiter temperature and at a chronic accelerational force of the order of 3 x 10(-5) times earth gravity. Weights and hormone content of the microgravity seedlings were, with minor exceptions, not statistically different from seedlings grown in normal gravity. The tissues of the shuttle-grown plants appeared normal and the seedlings differed only in the lack of orientation of roots and shoots. These findings, based upon 5 d of growth in microgravity, cannot be extrapolated to growth in microgravity for weeks, months, and years, as might occur on a space station. Nonetheless, it is encouraging, for prospects of bioregeneration of the atmosphere and food production in a space station, that no pronounced differences in the parameters measured were apparent during the 5 d of plant seedling growth in microgravity.

Schulze, A.; Jensen, P. J.; Desrosiers, M.; Buta, J. G.; Bandurski, R. S.

1992-01-01

382

Transport of the two natural auxins, indole-3-butyric acid and indole-3-acetic acid, in Arabidopsis  

NASA Technical Reports Server (NTRS)

Polar transport of the natural auxin indole-3-acetic acid (IAA) is important in a number of plant developmental processes. However, few studies have investigated the polar transport of other endogenous auxins, such as indole-3-butyric acid (IBA), in Arabidopsis. This study details the similarities and differences between IBA and IAA transport in several tissues of Arabidopsis. In the inflorescence axis, no significant IBA movement was detected, whereas IAA is transported in a basipetal direction from the meristem tip. In young seedlings, both IBA and IAA were transported only in a basipetal direction in the hypocotyl. In roots, both auxins moved in two distinct polarities and in specific tissues. The kinetics of IBA and IAA transport appear similar, with transport rates of 8 to 10 mm per hour. In addition, IBA transport, like IAA transport, is saturable at high concentrations of auxin, suggesting that IBA transport is protein mediated. Interestingly, IAA efflux inhibitors and mutations in genes encoding putative IAA transport proteins reduce IAA transport but do not alter IBA movement, suggesting that different auxin transport protein complexes are likely to mediate IBA and IAA transport. Finally, the physiological effects of IBA and IAA on hypocotyl elongation under several light conditions were examined and analyzed in the context of the differences in IBA and IAA transport. Together, these results present a detailed picture of IBA transport and provide the basis for a better understanding of the transport of these two endogenous auxins.

Rashotte, Aaron M.; Poupart, Julie; Waddell, Candace S.; Muday, Gloria K.; Brown, C. S. (Principal Investigator)

2003-01-01

383

40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...  

Code of Federal Regulations, 2012 CFR

...acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721.2076 Protection...acetate, calcium magnesium potassium sodium salt. (a) Chemical substance and significant...acetate, calcium magnesium potassium sodium salt (PMN P-00-7; CAS...

2012-07-01

384

The role of cholinergic anti-inflammatory pathway in acetic acid-induced colonic inflammation in the rat.  

PubMed

The "cholinergic anti-inflammatory pathway" provides neurological modulation of cytokine synthesis to limit the magnitude of the immune response. This study aimed to evaluate the impact of the cholinergic anti-inflammatory pathway on the extent of tissue integrity, oxidant-antioxidant status and neutrophil infiltration to the inflamed organ in a rat model of acetic acid-induced colitis. Colitis was induced by intrarectal administration of 5% acetic acid (1ml) to Sprague-Dawley rats (200-250g; n=7-8 per group). Control group received an equal volume of saline intrarectally. The rats were treated with either nicotine (1mg/kg/day) or huperzine A (0.1mg/kg/day) intraperitoneally for 3 days. After decapitation, the distal colon was scored macroscopically and microscopically. Tissue samples were used for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels, and myeloperoxidase (MPO) activity. Formation of reactive oxygen species was monitored by using chemiluminescence (CL). Nuclear factor (NF)-?B expression was evaluated in colonic samples via immunohistochemical analysis. Trunk blood was collected for the assessment of tumor necrosis factor (TNF)-?, interleukin (IL)-1?, IL-10, resistin and visfatin levels. Both nicotine and huperzine A reduced the extent of colonic lesions, increased colonic MDA level, high MPO activity and NF-?B expression in the colitis group. Elevation of serum IL-1? level due to colitis was also attenuated by both treatments. Additionally, huperzine A was effective to reverse colitis-induced high lucigenin-enhanced CL values and serum TNF-? levels. Colitis group revealed decreased serum visfatin levels compared to control group which was completely reversed by nicotine. In conclusion, modulation of the cholinergic system either by nicotine or ACh esterase inhibition improved acetic acid-induced colonic inflammation as confirmed by macroscopic and microscopic examination and biochemical assays. PMID:23810507

Kolgazi, Meltem; Uslu, Unal; Yuksel, Meral; Velioglu-Ogunc, Ayliz; Ercan, Feriha; Alican, Inci

2013-09-01

385

The Healing Effect of Teucrium polium in Acetic Acid-Induced Ulcerative Colitis in the Dog as an Animal Model  

PubMed Central

BACKGROUND Inflammatory bowel diseases (IBD), which include ulcerative colitis (UC) and Crohn’s disease (CD), are debilitating and chronic disorders with unpredictable courses and complicated treatment measures. Therefore, an efficient treatment protocol seems necessary as therapeutic prophylaxis for these disorders.This study aims to determine the healing effect of Teucrium polium (T. polium) in acetic acid-induced UC in an experimental dog model. METHODS From September to December 2010, eight male (20-25 kg) crossbred dogs were used for induction of UC by 6% acetic acid, transrectally. After one week, three biopsies (10, 20 and 30 cm proximal to the anal verge) were taken from the colon of each animal for histological studies. In the presence of UC, 400 mg/kg/day of T. polium extract was administered orally and transrectally (via enema) for 30 days in six of the dogs. The remaining two dogs were used as controls and did not receive T. polium. Multiple biopsies were taken 7, 14, and 30 days after discontinuation of T. polium in the same manner as before treatment. RESULTS After administration of acetic acid, we noted the presence of multiple ulcers, diffuse inflammation, PMN infiltration in the lamina propria, glandular destruction and goblet cell depletion. Treatment with T. polium restored the colonic architecture with an increased number of healthy cells and a reduction in inflammatory cells. Damage of the surface epithelial cells and mucosal layer of the lumen were reversed, which lead to faster ulcer healing. CONCLUSION T. polium may be a treatment choice for UC and can broaden the current therapy options for UC.

Mehrabani, Davood; Bahrami, Faranak; Hosseini, Seyed Vahid; Ashraf, Mohammad Javad; Tanideh, Nader; Rezaianzadeh, Abbas; Amini, Masoud; Amini, Afshin

2012-01-01

386

Conversion of endogenous indole-3-butyric acid to indole-3-acetic acid drives cell expansion in Arabidopsis seedlings.  

PubMed

Genetic evidence in Arabidopsis (Arabidopsis thaliana) suggests that the auxin precursor indole-3-butyric acid (IBA) is converted into active indole-3-acetic acid (IAA) by peroxisomal beta-oxidation; however, direct evidence that Arabidopsis converts IBA to IAA is lacking, and the role of IBA-derived IAA is not well understood. In this work, we directly demonstrated that Arabidopsis seedlings convert IBA to IAA. Moreover, we found that several IBA-resistant, IAA-sensitive mutants were deficient in IBA-to-IAA conversion, including the indole-3-butyric acid response1 (ibr1) ibr3 ibr10 triple mutant, which is defective in three enzymes likely to be directly involved in peroxisomal IBA beta-oxidation. In addition to IBA-to-IAA conversion defects, the ibr1 ibr3 ibr10 triple mutant displayed shorter root hairs and smaller cotyledons than wild type; these cell expansion defects are suggestive of low IAA levels in certain tissues. Consistent with this possibility, we could rescue the ibr1 ibr3 ibr10 short-root-hair phenotype with exogenous auxin. A triple mutant defective in hydrolysis of IAA-amino acid conjugates, a second class of IAA precursor, displayed reduced hypocotyl elongation but normal cotyledon size and only slightly reduced root hair lengths. Our data suggest that IBA beta-oxidation and IAA-amino acid conjugate hydrolysis provide auxin for partially distinct developmental processes and that IBA-derived IAA plays a major role in driving root hair and cotyledon cell expansion during seedling development. PMID:20562230

Strader, Lucia C; Culler, Angela Hendrickson; Cohen, Jerry D; Bartel, Bonnie

2010-08-01

387

Effects of urea and acetic acid on the heme axial ligation structure of ferric myoglobin at very acidic pH  

Microsoft Academic Search

The heme iron coordination of ferric myoglobin (Mb) in the presence of 9.0M urea and 8.0M acetic acid at acidic pH values has been probed by electronic absorption, magnetic circular dichroism and resonance Raman spectroscopic techniques. Unlike Mb at pH 2.0, where heme is not released from the protein despite the acid denaturation and the loss of the axial ligand,

Enrica Droghetti; Suganya Sumithran; Masanori Sono; Marián Antalík; Milan Fedurco; John H. Dawson; Giulietta Smulevich

2009-01-01

388

Electrochemical sensor for 2,4-dichlorophenoxy acetic acid using molecularly imprinted polypyrrole membrane as recognition element  

Microsoft Academic Search

An electrochemical sensor based on molecularly imprinted polypyrrole membranes is reported for the determination of 2,4-dichlorophenoxy\\u000a acetic acid (2,4-D). The sensor was prepared by electropolymerization of pyrrole on a glassy carbon electrode in the presence\\u000a of 2,4-D as a template. The template was removed by overoxidation at +1.3 V in buffer solution. The sensor can effectively\\u000a improve the reductive properties of

Chenggen Xie; Shan Gao; Qingbao Guo; Ke Xu

2010-01-01

389

Crystal growth, structure analysis and characterisation of 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid single crystal  

NASA Astrophysics Data System (ADS)

Single crystal of dielectric material 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid has been grown by slow evaporation solution growth method. The grown crystal was harvested in 25 days. The crystal structure was analyzed by Single crystal X - ray diffraction. UV-vis-NIR analysis was performed to examine the optical property of the grown crystal. The thermal property of the grown crystal was studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The dielectric measurements were carried out and the dielectric constant was calculated and plotted at all frequencies.

Sankari, R. Siva; Perumal, Rajesh Narayana

2014-04-01

390

Vapor-phase esterification of acetic acid with ethanol catalyzed by a macroporous sulfonated styrene-divinylbenzene (20%) resin  

SciTech Connect

The kinetics of the vapor-phase (85-120/sup 0/C) esterification of acetic acid with ethyl alcohol, at atmospheric pressure, catalyzed by a macroporous sulfonated styrene-divinylbenzene (DVB;20%) resin, has been studied. A simple first-order model (r = kp/sub 1/) fits experimental kinetic data properly for a constant reactants ratio. Discussion by means of L-H-H-W models shows that the rate-controlling step is the surface reaction with a single-site mechanism. The apparent activation energy is 4000 cal/mol.

Gimenez, J.; Costa, J.; Cervera, S.

1987-02-01

391

Acetic acid as a sclerosing agent for renal cysts: Comparison with ethanol in follow-up results  

Microsoft Academic Search

Purpose: To compare follow-up results of sclerotherapy for renal cyst using 50% acetic acid with those using 99% ethanol as sclerosing\\u000a agents.\\u000a \\u000a \\u000a Methods: Eighty-one patients underwent sclerotherapy and 58 patients, 23 males, 35 females, aged 6–76 years, having a total of 60\\u000a cysts, were included in this study; the others were lost to follow-up. The renal cysts were diagnosed by

Tae-Seok Seo; Joo Hyeong Oh; Yup Yoon; Joo Won Lim; Seong Jin Park; Sung-Goo Chang; Yang Hyeon Jeon

2000-01-01

392

The role of water co-adsorption on the modification of ZnO nanowires using acetic acid.  

PubMed

Density functional theory (DFT) and Car-Parinello molecular dynamic simulations were employed to investigate the interaction of acetic acid with non-polar facets of ultra-thin ZnO nanowires. We consider both a dry and a water environment as well as different molecule coverages for the hydrated system. Our calculations reveal that the fully-covered nanowire is energetically favored in the aqueous environment at room temperature. We also identified a minor influence of liquid water on the denticity of the ligands for the fully modified system. However, a monodentate adsorption is expected for a half-covered nanowire due to strong ligand-water interactions. PMID:24668002

Domínguez, Adriel; grosse Holthaus, Svea; Köppen, Susan; Frauenheim, Thomas; da Rosa, Andreia Luisa

2014-05-14

393

Genotoxic effect of 2,4-dichlorophenoxy acetic acid and its metabolite 2,4-dichlorophenol in mouse  

Microsoft Academic Search

The cytogenetic effect of 2,4-dichlorophenoxy acetic acid (2,4-D) and its metabolite 2,4-dichlorophenol (2,4-DCP) was studied in bone-marrow, germ cells and sperm head abnormalities in the treated mice. Swiss mice were treated orally by gavage with 2,4-D at 1.7, 3.3 and 33mgkg?1BW (1\\/200, 1\\/100 and 1\\/10 of LD50). 2,4-DCP was intraperitoneally (i.p.) injected at 36, 72 and 180mgkg?1BW (1\\/10, 1\\/5, 1\\/2

Soheir M Amer; Fawzia A. E Aly

2001-01-01

394

Unusual kinetic properties of anionic tobacco peroxidase related to the mechanism of oxidation of indole-3-acetic acid  

Microsoft Academic Search

Anionic tobacco peroxidase (TOP) (mol wt 36 kDa, pI 3.5) was purified from transgenic tobacco plants with the yield of 60\\u000a mg\\/1 kg leaves. The enzyme exhibits unusual properties, i.e., Compound I is less reactive than Compound II. The enzyme was\\u000a investigated in oxidation of indole-3-acetic acid (IAA) oxidation by oxygen in the air. The aerobic steady-state spectral\\u000a studies reveal

I. G. Gazarian; G. A. Ashby; R. N. F. Thorneley; L. M. Lagrimini

1996-01-01

395

Selective activation of vitamin D receptor by lithocholic acid acetate, a bile acid derivative  

Microsoft Academic Search

The vitamin D receptor (VDR), a member of the nuclear receptor superfamily, mediates the biological ac- tions of the active form of vitamin D, 1 ? ,25-dihydroxyvita- min D 3 . It regulates calcium homeostasis, immunity, cellular differentiation, and other physiological processes. Recently, VDR was found to respond to bile acids as well as other nu- clear receptors, farnesoid X

Ryutaro Adachi; Yoshio Honma; Hiroyuki Masuno; Katsuyoshi Kawana; Iichiro Shimomura; Sachiko Yamada; Makoto Makishima

2004-01-01

396

Aspects of the thermal oxidation of ethylene vinyl acetate copolymer  

Microsoft Academic Search

The thermal oxidation of ethylene-vinyl acetate copolymer [EVA-17 and 28% w\\/w VA (vinyl acetate) units] has been examined by thermo-gravimetric and hydroperoxide analysis, FTIR (Fourier transform infra-red) fluorescence spectroscopy and yellowness index. Thermal analysis indicates the initial loss of acetic acid followed by oxidation and breakdown of the main chain. The degradation rate is greater in an oxygen atmosphere as

Norman S. Allen; Michele Edge; Miguel Rodriguez; Cristopher M. Liauw; Eusebio Fontan

2000-01-01

397

Mesophilic syntrophic acetate oxidation during methane formation in biogas reactors  

Microsoft Academic Search

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

Anna Schnürer; Gerhard Zellner; Bo H. Svensson

1999-01-01

398

Acetate metabolism and its regulation in Corynebacterium glutamicum.  

PubMed

The amino acid producing Corynebacterium glutamicum grows aerobically on a variety of carbohydrates and organic acids as single or combined sources of carbon and energy. Among the substrates metabolized are glucose and acetate which both can also serve as substrates for amino acid production. Based on biochemical, genetic and regulatory studies and on quantitative determination of metabolic fluxes during utilization of acetate and/or glucose, this review summarizes the present knowledge on the different steps of the fundamental pathways of acetate utilization in C. glutamicum, namely, on acetate transport, acetate activation, tricarboxylic acid (TCA) cycle, glyoxylate cycle and gluconeogenesis. It becomes evident that, although the pathways of acetate utilization follow the same theme in many bacteria, important biochemical, genetic and regulatory peculiarities exist in C. glutamicum. Recent genome wide and comparative expression analyses in C. glutamicum cells grown on glucose and on acetate substantiated previously identified transcriptional regulation of acetate activating enzymes and of glyoxylate cycle enzymes. Additionally, a variety of genes obviously also under transcriptional control in response to the presence or absence of acetate in the growth medium were uncovered. These genes, thus also belonging to the acetate stimulon of C. glutamicum, include genes coding for TCA cycle enzymes (e.g. aconitase and succinate dehydrogenase), for gluconeogenesis (phosphoenolpyruvate carboxykinase), for glycolysis (pyruvate dehydrogenase E1) and genes coding for proteins with hitherto unknown function. Although the basic mechanism of transcriptional regulation of the enzymes involved in acetate metabolism is not yet understood, some recent findings led to a better understanding of the adaptation of C. glutamicum to acetate at the molecular level. PMID:12948633

Gerstmeir, Robert; Wendisch, Volker F; Schnicke, Stephanie; Ruan, Hong; Farwick, Mike; Reinscheid, Dieter; Eikmanns, Bernhard J

2003-09-01

399

Microbial removal of acetate selectively from sugar mixtures  

Microsoft Academic Search

Acetic acid is an unavoidable constituent of the biomass hydrolysates generated from acetylated hemicellulose and lignin,\\u000a and acetate affects the performance of microbes used to convert these hydrolysates into biofuels or other biochemicals. In\\u000a this study, acetate was selectively removed from synthetic mixtures of glucose and xylose using metabolically engineered Escherichia\\u000a coli strains having mutations in the glucose phosphotransferase system

Arun Lakshmanaswamy; Eashwar Rajaraman; Mark A. Eiteman; Elliot Altman

400

Effect of ethanolic extract of leaves of Paederia foetida Linn. on acetic acid induced colitis in albino rats  

PubMed Central

Objectives: To evaluate the effect of ethanolic extract of leaves of Paederia foetida on acetic acid induced colitis in albino rats. Materials and Methods: Ethanolic extract of Paederia foetida (EEPF) was prepared by percolation method. Acute toxicity test was done by using Organization for Economic Cooperation and Development guidelines. Albino rats were divided into four groups of five animals each. Groups A and B received 3% gum acacia. Groups C and D received EEPF 500 mg/kg body weight (BW) and 5-aminosalisylic acid 100 mg/kg BW respectively. Colitis was induced by transrectal administration of 4% acetic acid on 5th day. All animals were sacrificed after 48 h of colitis induction and distal 10 cm of the colon was dissected. Colon was weighed for disease activity index (DAI) and scored macroscopically and microscopically. Biochemical assessment of tissue myeloperoxidase (MPO), catalase (CAT) and superoxide dismutase (SOD) was done in colonic tissue homogenate and malondialdehyde (MDA) was estimated in serum. Results: P. foetida showed significant (P < 0.05) reduction in DAI, macroscopic and microscopic lesion score as well as significant (P < 0.05) improvement in MPO, MDA, CAT, and SOD level as compared to Group B. Conclusions: The ethanolic extract of leaves of P. foetida showed significant amelioration of experimentally induced colitis, which may be attributed to its anti-inflammatory and antioxidant property.

Das, Swarnamoni; Kanodia, Lalit; Mukherjee, Apurba; Hakim, Abdul

2013-01-01

401

Linalyl Acetate Is Metabolized by Pseudomonas incognita with the Acetoxy Group Intact  

PubMed Central

Metabolism of linalyl acetate by Pseudomonas incognita isolated by enrichment culture on the acyclic monoterpene alcohol linalool was studied. Biodegradation of linalyl acetate by this strain resulted in the formation of linalool, linalool-8-carboxylic acid, oleuropeic acid, and ?5-4-acetoxy-4-methyl hexenoic acid. Cells adapted to linalyl acetate metabolized linalyl acetate-8-aldehyde to linalool-8-carboxylic acid, linalyl acetate-8-carboxylic acid, ?5-4-acetoxy-4-methyl hexenoic acid, and geraniol-8-carboxylic acid. Resting cell suspensions previously grown with linalyl acetate oxidized linalyl acetate-8-aldehyde to linalyl acetate-8-carboxylic acid, ?5-4-acetoxy-4-methyl hexenoic acid, and pyruvic acid. The crude cell-free extract (10,000 g of supernatant), obtained from the sonicate of linalyl acetate-grown cells, was shown to contain enzyme systems responsible for the formation of linalyl acetate-8-carboxylic acid and linalool-8-carboxylic acid from linalyl acetate. The same supernatant contained NAD-linked alcohol and aldehyde dehydrogenases involved in the formation of linalyl acetate-8-aldehyde and linalyl acetate-8-carboxylic acid, respectively. On the basis of various metabolites isolated from the culture medium, resting cell experiments, growth and manometric studies carried out with the isolated metabolites as well as related synthetic analogs, and the preliminary enzymatic studies performed with the cell-free extract, a probable pathway for the microbial degradation of linalyl acetate with the acetoxy group intact is suggested.

Renganathan, V.; Madyastha, K. Madhava

1983-01-01

402

Modeling the Effects of Sodium Chloride, Acetic Acid, and Intracellular pH on Survival of Escherichia coli O157:H7 ? †  

PubMed Central

Microbiological safety has been a critical issue for acid and acidified foods since it became clear that acid-tolerant pathogens such as Escherichia coli O157:H7 can survive (even though they are unable to grow) in a pH range of 3 to 4, which is typical for these classes of food products. The primary antimicrobial compounds in these products are acetic acid and NaCl, which can alter the intracellular physiology of E. coli O157:H7, leading to cell death. For combinations of acetic acid and NaCl at pH 3.2 (a pH value typical for non-heat-processed acidified vegetables), survival curves were described by using a Weibull model. The data revealed a protective effect of NaCl concentration on cell survival for selected acetic acid concentrations. The intracellular pH of an E. coli O157:H7 strain exposed to acetic acid concentrations of up to 40 mM and NaCl concentrations between 2 and 4% was determined. A reduction in the intracellular pH was observed for increasing acetic acid concentrations with an external pH of 3.2. Comparing intracellular pH with Weibull model predictions showed that decreases in intracellular pH were significantly correlated with the corresponding times required to achieve a 5-log reduction in the number of bacteria.

Hosein, Althea M.; Breidt, Frederick; Smith, Charles E.

2011-01-01

403

Protective effect of naringenin on acetic acid-induced ulcerative colitis in rats  

PubMed Central

AIM: To evaluate the ameliorative effect of naringenin (NG) during ulcerative colitis (UC) in rats. METHODS: Rats were treated with three different doses (25, 50 and 100 mg/kg per day) of NG and a single dose of mesalazine (MES, 300 mg/kg per day) for seven days prior to ulcerative colitis induction by 4% acetic acid (AA). Twenty four hours after AA rectal administration, animals were scarified and the colonic tissues were dissected. Colonic mucus content was estimated using Alcian blue dye binding technique. In colon tissues, levels of total glutathione sulphadryls (T-GSH), non-protein sulphadryls (NP-SH) and thiobarbituric acid reactive substances (TBARS) were evaluated. The activities of the antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD) were measured. Concentrations of nucleic acids (DNA and RNA) and total protein were also estimated in colon tissues. Colonic levels of tumor necrosis factor-? (TNF-?), interleukin-1? (IL-1?), interleukin-6 (IL-6), prostaglandin E2 (PGE2) and nitric oxide (NO) were estimated. In cross section of colitis tissue the histopathological changes were observed. RESULTS: Colonic mucus content was decreased in AA compared to controls (587.09 ± 65.59 mg/kg vs 941.78 ± 68.41 mg/kg, P < 0.001). AA administration markedly reduced T-GSH (5.25 ± 0.37 nmol/L vs 3.04 ± 0.24 nmol/L, P < 0.01), NP-SH (3.16 ± 0.04 nmol/L vs 2.16 ± 0.30 nmol/L, P < 0.01), CAT (6.77 ± 0.40 U/mg vs 3.04 ± 0.2 U/mg, P < 0.01) and SOD (3.10 ± 0.11 U/mg vs 1.77 ± 0.18 U/mg, P < 0.01) while TBARS, TNF-?, IL-1?, IL-6, PGE2 and NO levels (15.09 ± 3.84 nmol/L vs 59.90 ± 16.34 nmol/L, P < 0.01; 113.56 ± 1.91 pg/mg vs 134.24 ± 4.77 pg/mg, P < 0.01; 209.20 ± 36.38 pg/mg vs 422.19 ± 31.47 pg/mg, P < 0.01; 250.83 ± 25.09 pg/mg vs 638.58 ± 115.9 pg/mg, P < 0.01; 248.19 ± 36.98 pg/mg vs 541.74 ± 58.34 pg/mg, P < 0.01 and 81.26 ± 2.98 mmol/g vs 101.90 ± 10.73 mmol/g, P < 0.001) were increased in colon of rats with UC compared controls respectively.Naringenin supplementation, significantly and dose dependently increased the colonic mucus content. The elevated TBARS levels were significantly decreased (39.35 ± 5.86 nmol/L, P < 0.05; 26.74 ± 3.17 nmol/L, P < 0.01 nmol/L and 17.74 ± 2.69 nmol/L, P < 0.01) compared to AA (59.90 ± 16.34 nmol/L) group while the decreased levels of T-GSH and NP-SH and activities of CAT and SOD found increased by NG treatments in dose dependent manner. The decreased values of nucleic acids and total protein in AA group were also significantly (P < 0.01) increased in all three NG supplemented groups respectively. NG pretreatment inhibited the TNF-? levels (123.76 ± 3.76 pg/mg, 122.62 ± 3.41 pg/mg and 121.51 ± 2.61 pg/mg vs 134.24 ± 4.78 pg/mg, P < 0.05) compared to AA group, respectively. Interleukins, IL-1? and IL-6 levels were also decreased in NG50 + AA (314.37 ± 16.31 pg/mg and 292.58 ± 23.68 pg/mg, P < 0.05) and NG100 + AA (416.72 ± 49.62 pg/mg and 407.96 ± 43.87 pg/mg, P < 0.05) when compared to AA (352.46 ± 8.58 pg/mg and 638.58 ± 115.98 pg/mg) group. Similar decrease (P < 0.05) was seen in PGE2 and NO values when compared to AA group. The group pretreated with MES, as a reference drug, showed significant (P < 0.01) protection against the changes induced in colon tissue by AA administration respectively. CONCLUSION: In present study, NG produced antioxidant and anti-inflammatory effects demonstrating protective effect in inflammatory bowel disease.

Al-Rejaie, Salim S; Abuohashish, Hatem M; Al-Enazi, Maher M; Al-Assaf, Abdullah H; Parmar, Mihir Y; Ahmed, Mohammed M

2013-01-01

404

DESOXYCORTICOSTERONE ACETATE AND WOUND HEALING  

PubMed Central

The effect of desoxycorticosterone acetate (DCA) on the granulation tissue of healing and healed linear laparotomy wounds was studied in young adult male guinea pigs maintained on a complete diet and on a known intake of ascorbic acid. DCA induces the production of an excessive amount of granulation tissue, as evidenced by a relatively great number of fibroblasts and by a larger amount of ground substance. This effect was accompanied by a slight to moderate lag in the maturation process of both cellular and intercellular elements. These changes were observed when DCA administration was begun 5 days prior to operation, but were less obvious or absent if DCA was injected, beginning on the 5th or 10th postoperative day. The results indicate that the action of DCA on immature, proliferating connective tissue is marked, and is considerably less or absent when connective tissue elements have reached partial or almost complete maturity. The effect of DCA on connective tissue does not appear to rest on the basis of an altered nutritional status. Chemical and histochemical studies of the adrenals suggest that the action of DCA on connective tissue is probably mediated through a disturbance of adrenocortical function, namely an imbalance between hormones of the zona glomerulosa (excess of DCA) and those of the zona fasciculata (deficiency of glucocorticoids). The presence of changes in granulation tissue and the lack of them in mature resting connective tissue of DCA-treated guinea pigs confirm the view that a profound difference in the response mechanism exists between resting and actively proliferating connective tissue.

Pirani, Conrad L.; Stepto, Robert C.; Sutherland, Kenneth

1951-01-01

405

Ethyl 2-Cyano-2-(4-nitrophenylsulfonyloxyimino)acetate-Mediated Lossen Rearrangement: Single-Pot Racemization-Free Synthesis of Hydroxamic Acids and Ureas from Carboxylic Acids.  

PubMed

Ethyl 2-cyano-2-(4-nitrophenylsulfonyloxyimino)acetate (4-NBsOXY) mediated Lossen rearrangement and its application for the synthesis of ureas is demonstrated. Required hydroxamic acids for the Lossen rearrangements were synthesized from carboxylic acids using the same reagent. Finally, reaction of an amine with the produced isocyanate resulted in urea. Good yields without racemization were achieved under milder and simpler reaction conditions. Reactions are compatible with common N-protecting groups, such as Boc, Fmoc, Cbz, and benzyl, as well as various OH protecting groups, such as (t)Bu and Bzl. Conversion from carboxylic acid to urea is achieved in one pot. Most importantly, byproducts Oxyma [ethyl 2-cyano-2-(hydroxyimino)acetate] and 4-nitrobenzenesulfonic acid can be recovered easily and can be recycled to prepare the reagent. Thus, the method is environmentally friendly and cost-effective. PMID:24678821

Thalluri, Kishore; Manne, Srinivasa Rao; Dev, Dharm; Mandal, Bhubaneswar

2014-05-01

406

Partitioning of Acetate, Formate and Phosphates Around the Water/Steam Cycle.  

National Technical Information Service (NTIS)

Volatilities of formic acid, acetic acid, sodium acetate, phosphoric acid, sodium dihydrogen phosphate and sodium monohydrogen phosphate have been measured at temperatures up to 350degC using a corrosion-resistant static cell with sampling of both phases....

M. S. Guszkiewicz D. B. Joyce S. L. Marshall D. A. Palmer J. M. Simonson

2000-01-01

407

Wet deposition and related atmospheric chemistry in the São Paulo metropolis, Brazil: Part 2—contribution of formic and acetic acids  

NASA Astrophysics Data System (ADS)

Wet-only deposition samples were collected at a site in the urban area of the São Paulo metropolis between February (end of the rainy summer) and October (beginning of spring) 2000, an atypical period due to rainfall 40% below the 30-year average. The majority ions in rainwater were measured by capillary zone electrophoresis with contactless conductivity detection, CZE-CCD, applied for the first time to the organic anions acetate and formate. The volume weight mean (VWM) concentrations of the majority anions NO 3-, SO 42- and Cl - were, respectively, 15.6, 9.5 and 4.7 ?mol l -1. The VWM concentration of HCOO -t, (HCOO -+HCOOH) was 17.0 ?mol l -1, about twice the 8.9 ?mol l -1 of CH 3COO -t. The VWM concentration of free H + was low ( 16.9 ?mol l -1), corresponding to pH 4.77. This denotes the relevance of species like ammonia, analyzed as NH4+ ( VWM=27.9 ?mol l -1), and calcium carbonate ( VWM=5.3 ?mol l -1 Ca2+) as partial neutralizers of the acidity. By hypothetically assuming that H + is the only counterion of the non-sea-salt fraction of the dissociated anions, their contribution to the total potential acidity would decrease in the following order: sulfate (29%), formate (29%), nitrate (26%), acetate (15%) and chloride (1%). The 44% potential participation of the carboxylic acids reveals their importance to the acidity of São Paulo's rainwater during the study period. Direct vehicular emission of lower carboxylic acids and aldehydes (in particular, acetic acid and acetaldehyde) is singularly high in the metropolis due to the extensive use of ethanol and gasohol (containing ˜20% of ethanol) as fuels of the light fleet of 5.5 million cars; in addition, regional atmospheric conditions favor the photochemical formation of the acids, since concentrations of ozone and aldehydes are high and solar irradiation is intense at the 23°34'S latitude. The presence of higher concentrations of HCOOH than CH 3COOH indicates a prevalence of its photochemical production by H 2CO oxidation in the atmosphere.

Fornaro, Adalgiza; Gutz, Ivano G. R.

408

FeCl3 and acetic acid co-catalyzed hydrolysis of corncob for improving furfural production and lignin removal from residue.  

PubMed

In order to increase furfural yield and lignin removal, both FeCl(3) and acetic acid were used to co-catalyze the hydrolysis of corncob. A series of experiments were carried out to investigate the effects of acetic acid, FeCl(3) concentrations and temperatures on furfural production and residue characteristics. The results showed that high FeCl(3) concentrations caused serious cellulose degradation while acetic acid was more effective for lignin removal. A maximum furfural yield of 67.89% (35.74% higher than that in conventional sulfuric acid-catalyzed process) was obtained at 180°C in the presence of 20mM of FeCl(3) and 3% of acetic acid. Simultaneously, lignin removal reached 54.79%, and 74.29% of the cellulose was remained for further utilization. Acetic acid and FeCl(3) co-catalyzed hydrolysis was not only a high efficiency and environmental friendly technique, but also provided a possibility to utilize the furfural residue for ethanol production and other industries. PMID:22940337

Mao, Liaoyuan; Zhang, Lei; Gao, Ningbo; Li, Aimin

2012-11-01

409

Sulphydryl groups and iodo-(/sup 3/H)acetic acid labeling in proteolipids from Torpedo electroplax  

SciTech Connect

Several fractions of proteolipids from Torpedo electroplax were separated by DEAE-cellulose chromatography in organic solvents, and the sulphydryl groups were determined by a spectrophotometric method. On the same fractions the covalent labeling with iodo-(/sup 3/H)acetic acid to sulphydryl groups was studied. In total proteolipids there were 30.3 nmol/mg protein of sulphydryl groups of which 20.6 nmoles were in the form of disulfide bonds and 10.9 nmol as free--SH groups. The highest content of sulphydryl groups (36.7 nmol/mg protein) was found in fraction II; while fraction I, that binds the cholinergic ligands, has a lower content (23.7 nmol/mg protein). The 42 Kdaltons polypeptide, which is the major band in Fraction II, has the strongest labeling with iodo-(/sup 3/H)acetic acid, while the 39 Kdaltons cholinergic polypeptide shows a lower labeling. The importance of proteolipids as channel-forming macromolecules is discussed in connection with the possible significance of the 42 Kdaltons polypeptide.

Criado, M.; Aguilar, J.S.; De Robertis, E.

1983-05-01

410

Application of culture culture-independent molecular biology based methods to evaluate acetic acid bacteria diversity during vinegar processing.  

PubMed

Acetic acid bacteria (AAB) are considered fastidious microorganisms because they are difficult to isolate and cultivate. Different molecular approaches were taken to detect AAB diversity, independently of their capacity to grow in culture media. Those methods were tested in samples that originated during traditional vinegar production. Bacterial diversity was assessed by analysis of 16S rRNA gene, obtained by PCR amplifications of DNA extracted directly from the acetification container. Bacterial composition was analyzed by RFLP-PCR of 16S rRNA gene, Temporal Temperature Gradient Gel Electrophoresis (TTGE) separation of amplicons containing region V3-V5 of 16S rRNA gene and cloning of those amplicons. TTGE bands and clones were grouped based on their electrophoretic pattern similarity and sequenced to be compared with reference strains. The main microorganism identified in vinegar was Acetobacter pasteurianus, which at the end of the acetification process was considered to be the only microorganism present. The diversity was the highest at 2% acetic acid, where indefinite species of Gluconacetobacter xylinus/europaeus/intermedius were also present. PMID:18571262

Ilabaca, Carolina; Navarrete, Paola; Mardones, Pamela; Romero, Jaime; Mas, Albert

2008-08-15

411

Effect of retinyl acetate, ascorbic acid and tocopherol supplementation of the feed on egg vitamin A content in Japanese quail.  

PubMed

The ration fed to laying Japanese quails was supplemented either with retinyl acetate (RA) (50 x 10(3) IU/kg, group A), ascorbic acid (500 mg/kg, group C), or with both substances in combination with each other (group AC) and with tocopheryl acetate (37.8 IU/kg; groups AE and ACE). On days 1, 8, 14, 20 and 28, some quantitative parameters of eggs (mass of egg-shell, albumen and egg yolk, retinoid content of egg yolk) were measured. The egg production parameters were not significantly affected by the supplementations. By the end of the second week, the total vitamin A (retinyl esters + retinol) concentrations of the egg yolk were significantly higher in the groups receiving supplemented feed (AC, AE and AEC) than in the control group. Two weeks later (on day 28), the vitamin A levels were elevated significantly in all groups except the group treated with ascorbic acid. From the point of view of vitamin A fortification of the egg yolk, the combined supplementations (groups AC, AE, AEC) seem to be more effective. The results indicate that vitamin A content of the egg yolk can be increased by a short-term RA supplementation of the laying ration. The retinoids present in the natural substances of eggs could possibly be a good source of vitamin A for humans. PMID:8908745

Bárdos, L; Sótér, G; Karchesz, K

1996-01-01

412

Rapid analysis of formic acid, acetic acid, and furfural in pretreated wheat straw hydrolysates and ethanol in a bioethanol fermentation using atmospheric pressure chemical ionisation mass spectrometry  

PubMed Central

Atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) offers advantages as a rapid analytical technique for the quantification of three biomass degradation products (acetic acid, formic acid and furfural) within pretreated wheat straw hydrolysates and the analysis of ethanol during fermentation. The data we obtained using APCI-MS correlated significantly with high-performance liquid chromatography analysis whilst offering the analyst minimal sample preparation and faster sample throughput.

2011-01-01

413

Permeation and Separation Characteristics of Acetic Acid?Water Mixtures Through Poly(Vinyl Alcohol)\\/Malic Acid Membranes by Evapomeation and Temperature Difference Controlled Evapomeation  

Microsoft Academic Search

The characteristics of permeation and separation of acetic acid?water mixtures through 85\\/15 (v\\/v) poly(vinyl alcohol)\\/malic acid (PVA\\/MA) membranes were investigated by evapomeation (EV) and temperature difference controlled evapomeation (TDEV) methods. The effects of permeation temperature, membrane surrounding temperature, and feed composition on the permeation rate and the separation factor were studied. The permeation rates increased but separation factors decreased with

Nuran I??klan; Oya ?anl?

2005-01-01

414

Net portal appearance of volatile fatty acids in sheep intraruminally infused with mixtures of acetate, propionate, isobutyrate, butyrate, and valerate.  

PubMed

The net portal appearance of volatile fatty acids (VFA) was investigated in four ruminally fistulated and multicatheterized sheep. During the experiments, the sheep were fed once every hour for 14 h and intraruminally infused with mixtures of VFA for the 12 h commencing 2 h after the initiation of the hourly feeding protocol. Paired arterial and portal blood samples were obtained hourly during the last 6 h of the experiments. In the control treatment (1), only water was infused intraruminally. In Treatments 2 through 4, the intraruminal infusion rates of propionate (40 mmol/h), isobutyrate (5 mmol/h), and valerate (5 mmol/h) were unchanged. In Treatments 2, 3, and 4, the acetate infusion rate was 100, 60, and 20 mmol/h, respectively, and the butyrate infusion rate was 10, 30, and 50 mmol/h, respectively. Thus, the infusion rate of VFA carbon was constant across Treatments 2 through 4. Portal recovery estimated from the increased net portal appearance in Treatments 2 through 4 compared to the control treatment was 85% for propionate and 60% for isobutyrate, and these recoveries were unaffected by treatment. The portal recovery of butyrate increased (from 21 to 32%) with increasing infusion rate of butyrate and decreasing infusion rate of acetate, as did the portal recovery of valerate (from 14 to 31%). The portal recovery of acetate was 55%, when measured as net portal appearance. Thus, it seems that the capacity for beta-oxidation in ruminal epithelium is limited, which would explain the increasing portal recovery of butyrate and valerate with increasing infusion rate of butyrate, when infusion rate of VFA carbon is unchanged. PMID:10834594

Kristensen, N B; Pierzynowski, S G; Danfaer, A

2000-05-01

415

Co-production of furfural and acetic acid from corncob using ZnCl2 through fast pyrolysis in a fluidized bed reactor.  

PubMed

Corncob was pyrolyzed using ZnCl2 in a pyrolysis plant equipped with a fluidized bed reactor to co-produce furfural and acetic acid. The effects of reaction conditions, the ZnCl2 content and contacting method of ZnCl2 with corncob on the yields of furfural and acetic acid were investigated. The pyrolysis was performed within the temperature range between 310 and 410°C, and the bio-oil yield were 30-60 wt% of the product. The furfural yield increased up to 8.2 wt%. The acetic acid yield was maximized with a value of 13.1 wt%. A lower feed rate in the presence of ZnCl2 was advantageous for the production of acetic acid. The fast pyrolysis of a smaller corncob sample mechanically mixed with 20 wt% of ZnCl2 gave rise to a distinct increase in furfural. A high selectivity for furfural and acetic acid in bio-oil would make the pyrolysis of corncob with ZnCl2 very economically attractive. PMID:23867536

Oh, Seung-Jin; Jung, Su-Hwa; Kim, Joo-Sik

2013-09-01

416

Gas-phase Synthesis of Precursors of Interstellar Glycine: A Computational Study of the Reactions of Acetic Acid with Hydroxylamine and Its Ionized and Protonated Derivatives  

NASA Astrophysics Data System (ADS)

A computational study of the reactions of hydroxylamine and its ionized and protonated derivatives with acetic acid is provided. The reaction of neutral hydroxylamine with acetic acid, despite being clearly exothermic, involves a very large energy barrier. The reaction of ionized hydroxylamine with acetic acid is also clearly exothermic, but again a significant energy barrier is found (around 24 kcal mol-1 at the CCSD(T) level). The reaction of the most stable protonated isomer of hydroxylamine, NH3OH+, with acetic acid also involves a high barrier (more than 27 kcal mol-1 at the CCSD(T) level). Only the higher energy isomer, NH2OH+ 2, leads to a sensibly lower energy barrier (about 2.3 kcal mol-1 at the CCSD(T) level). Nevertheless, an estimate of the reaction coefficient at low temperatures such as those reigning in the interstellar medium gives very low values. Therefore, it seems that precursors of interstellar glycine could not be efficiently produced from the reactions of hydroxylamine-derived ions with acetic acid.

Barrientos, Carmen; Redondo, Pilar; Largo, Laura; Rayón, Víctor M.; Largo, Antonio

2012-04-01

417

Solution-free, in situ preparation of nano/micro CuO/ZnO in dielectric barrier discharge for sensitive cataluminescence sensing of acetic acid.  

PubMed

The present work describes a new solution-free strategy for preparation of cluster-like nano/micro CuO/ZnO particles in dielectric barrier discharge (DBD) in which the brass acts as the inner electrode. The cataluminescence (CTL) behaviour of such prepared material for acetic acid was studied for analytical application. Under the optimized conditions, the linear range of CTL intensity versus concentration of acetic acid are 6 mg L(-1) to 500 mg L(-1) with the limit of detection (LOD) of 3 mg L(-1), no significant interference was found. The new method shows great advantages because it is a process without any solution and complex equipment. The synthetic material was directly used for the cataluminescence sensing of acetic acid without other preliminary treatment and it shows high selectivity, satisfactory stability, and better sensitivity and linearity. PMID:23671903

Xia, Hui; Zhou, Ronghui; Zheng, Chengbin; Wu, Peng; Tian, Yunfei; Hou, Xiandeng

2013-07-01

418

The Effect of Indole-3-acetic Acid and Other Growth Regulators on the Ripening of Avocado Fruits 1  

PubMed Central

Observations were made of the effects of several plant regulators, indole-3-acetic acid, kinetin, abscisic acid, and gibberellic acid, as well as of extracts prepared from leaves and fruit stalks on the respiration pattern, ethylene production, and the number of days to ripen of avocado fruits (Persea americana Mill.). These substances were vacuum infiltrated to insure good penetration and distribution. Kinetin, abscisic acid, gibberellic acid, and the extracts had no effect on either ripening time or on the respiration pattern and ethylene production of the fruits. Indoleacetic acid, however, had a marked effect on ripening. At high concentrations (100 and 1000 ?m), indoleacetic acid stimulated respiration and induced preclimacteric ethylene production, resulting in accelerated ripening of the fruits. At the low concentrations (1 and 10 ?m), it delayed ripening of fruits and suppressed the climacteric respiration and ethylene production. The results reinforce several previous observations with other fruits that auxins may largely constitute `resistance to ripening' and may be responsible for the lack of ripening shown by unpicked fruits.

Tingwa, Peter O.; Young, Roy E.

1975-01-01

419

Radical addition of methyldichlorosilane to vinyl acetate  

Microsoft Academic Search

The GC-MS method was used to identify the addition products of methyldichlorosilane to vinyl acetate. Radiation-induced addition of methyldichlorosilane to vinyl acetate produces 2-methyldichlorosilylethyl ethyl ether. The reaction follows a radical-chain mechanism. The ratio of the rate constants of methyldichlorosilyl radical addition to C=C and C=O to vinyl acetate amounts to 0.4±0.1 (303 K).

Yu. M. Lugovoi; N. P. Tarasova; G. Bourgeois; N. V. Bryantseva; V. V. Kostikov; C. Filliatre; A. G. Shostenko

1991-01-01

420

Graft polymerization of vinyl acetate onto silica  

Microsoft Academic Search

The free-radical graft polymerization of vi- nyl acetate onto nonporous silica particles was studied ex- perimentally. The grafting procedure consisted of surface activation with vinyltrimethoxysilane, followed by free-rad- ical graft polymerization of vinyl acetate in ethyl acetate with 2,2-azobis(2,4-dimethylpentanenitrile) initiator. Initial monomer concentration was varied from 10 to 40% by vol- ume and the reaction was spanned from 50 to

Van Nguyen; Wayne Yoshida; Yoram Cohen

2003-01-01

421

Miscibility of cellulose acetate with vinyl polymers  

Microsoft Academic Search

Binary blend films of cellulose acetate (CA) with flexible syntheticpolymers including poly(vinyl acetate) (PVAc), poly(N-vinyl pyrrolidone) (PVP),and poly(N-vinyl pyrrolidone-co-vinyl acetate) [P(VP-co-VAc)] were preparedfrommixed polymer solutions by solvent evaporation. Thermal analysis by DSC showedthat CA of any degree of substitution (DS) was not miscible with PVAc, but CAwith DS less than 2.8 was miscible with PVP to form homogeneous blends. Thestate

Yoshiharu Miyashita; Tetsuya Suzuki; Yoshiyuki Nishio

2002-01-01

422

Calcium magnesium acetate production and cost reduction  

SciTech Connect

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

Leuschner, A.P.

1988-02-01

423

Fatty Acid Synthase Is a Key Target in Multiple Essential Tumor Functions of Prostate Cancer: Uptake of Radiolabeled Acetate as a Predictor of the Targeted Therapy Outcome  

PubMed Central

Fatty acid synthase (FASN) expression is elevated in several cancers, and this over-expression is associated with poor prognosis. Inhibitors of FASN, such as orlistat, reportedly show antitumor effects against cancers that over-express FASN, making FASN a promising therapeutic target. However, large variations in FASN expression levels in individual tumors have been observed, and methods to predict FASN-targeted therapy outcome before treatment are required to avoid unnecessary treatment. In addition, how FASN inhibition affects tumor progression remains unclear. Here, we showed the method to predict FASN-targeted therapy outcome using radiolabeled acetate uptake and presented mechanisms of FASN inhibition with human prostate cancer cell lines, to provide the treatment strategy of FASN-targeted therapy. We revealed that tumor uptake of radiolabeled acetate reflected the FASN expression levels and sensitivity to FASN-targeted therapy with orlistat in vitro and in vivo. FASN-targeted therapy was noticeably effective against tumors with high FASN expression, which was indicated by high acetate uptake. To examine mechanisms, we established FASN knockdown prostate cancer cells by transduction of short-hairpin RNA against FASN and investigated the characteristics by analyses on morphology and cell behavior and microarray-based ge