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1

21 CFR 184.1021 - Benzoic acid.  

... 2014-04-01 2014-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and Drugs...Substances Affirmed as GRAS § 184.1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7 H6...

2014-04-01

2

21 CFR 582.3021 - Benzoic acid.  

Code of Federal Regulations, 2012 CFR

21 Food and Drugs 6 2012-04-01...2012-04-01 false Benzoic acid. 582.3021 Section 582.3021 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...582.3021 Benzoic acid. (a) Product....

2012-04-01

3

21 CFR 582.3021 - Benzoic acid.  

Code of Federal Regulations, 2013 CFR

21 Food and Drugs 6 2013-04-01...2013-04-01 false Benzoic acid. 582.3021 Section 582.3021 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...582.3021 Benzoic acid. (a) Product....

2013-04-01

4

21 CFR 582.3021 - Benzoic acid.  

Code of Federal Regulations, 2011 CFR

21 Food and Drugs 6 2011-04-01...2011-04-01 false Benzoic acid. 582.3021 Section 582.3021 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...582.3021 Benzoic acid. (a) Product....

2011-04-01

5

21 CFR 582.3021 - Benzoic acid.  

Code of Federal Regulations, 2010 CFR

21 Food and Drugs 6 2010-04-01...2010-04-01 false Benzoic acid. 582.3021 Section 582.3021 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...582.3021 Benzoic acid. (a) Product....

2010-04-01

6

21 CFR 582.3021 - Benzoic acid.  

21 Food and Drugs 6 2014-04-01...2014-04-01 false Benzoic acid. 582.3021 Section 582.3021 Food and Drugs FOOD AND DRUG ADMINISTRATION...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...582.3021 Benzoic acid. (a) Product....

2014-04-01

7

Relative reactivities of solid benzoic acids  

E-print Network

RELATIVE REACTIVITIES OF SOLID BENZOIC ACIDS A Thesis By EDWIN J, WARWAS Submitted to the Graduate College of the Texas A8rM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE January 1967' Major... Subject: Chemistry RELATIVE REACTIVITIES OF SOLID BENZOIC ACIDS A Thesis By EDWIN J. WARWAS Submitted to the Graduate College of the Texas ASSAM University in partial fulfillment of the requirements for the degree of MAST ER OF S CIENCE January...

Warwas, Edwin James

2012-06-07

8

Effect of formic acid and benzoic acid esters on grass preservation  

E-print Network

alternatives for benzoic acid and propionic acid was the high prices of these components. The esters of benzoicEffect of formic acid and benzoic acid esters on grass preservation A Rauramaa A Tommila J Ltd, Espoo Reseach Centre, PO Box 44, 02271 Espoo, Finland Formic acid is known to improve silage

Paris-Sud XI, Université de

9

A Kinetic Study on Benzoic Acid Pungency and Sensory Attributes of Benzoic Acid  

Microsoft Academic Search

Aqueous solutions of benzoic acid (BA) were evaluated by two methods: (i) sensory profile: a descriptive test of sensory attributes combined with semiquantitative analysis; and (ii) pungency intensity measures as a function of time: a computerized recording using specific software. Kinetic parameters evaluated were maximal intensity (IMAX), total time of pungency (Ttot), rates of increase (V1) and decrease (V2), half-life

Matilde E. Otero-Losada

1999-01-01

10

40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.  

Code of Federal Regulations, 2010 CFR

... false Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester...721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester...identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl...

2010-07-01

11

Study on QSTR of Benzoic Acid Compounds with MCI  

PubMed Central

Quantitative structure-toxicity relationship (QSTR) plays an important role in toxicity prediction. With the modified method, the quantum chemistry parameters of 57 benzoic acid compounds were calculated with modified molecular connectivity index (MCI) using Visual Basic Program Software, and the QSTR of benzoic acid compounds in mice via oral LD50 (acute toxicity) was studied. A model was built to more accurately predict the toxicity of benzoic acid compounds in mice via oral LD50: 39 benzoic acid compounds were used as a training dataset for building the regression model and 18 others as a forecasting dataset to test the prediction ability of the model using SAS 9.0 Program Software. The model is LogLD50 = 1.2399 × 0JA +2.6911 × 1JA – 0.4445 × JB (R2 = 0.9860), where 0JA is zero order connectivity index, 1JA is the first order connectivity index and JB = 0JA × 1JA is the cross factor. The model was shown to have a good forecasting ability. PMID:20480017

Li, Zuojing; Sun, Yezhi; Yan, Xinli; Meng, Fanhao

2010-01-01

12

Hydrogen bond mediated rotor-ring coupling in acetic acid-benzoic acid mixed dimer  

NASA Astrophysics Data System (ADS)

In this work we demonstrate that a doubly hydrogen-bonded interface of two carboxylic acid groups behaves as efficient conduit to transmit the rotor effects for IVR acceleration in a phenyl ring. The phenomenon has been demonstrated by measuring the resolved emission spectra following SVL excitations in S1 of a 1:1 mixed dimer between acetic acid and benzoic acid. The role of the methyl rotor has been ascertained by comparing the results with those obtained for an analogous dimeric system between formic acid and benzoic acid.

Nandi, Chayan K.; Hazra, Montu K.; Chakraborty, Tapas

2004-10-01

13

Isoniazid cocrystals with anti-oxidant hydroxy benzoic acids  

NASA Astrophysics Data System (ADS)

Isoniazid is the primary constituent of “triple therapy” used to effectively treat tuberculosis. In tuberculosis and other diseases, tissue inflammation and free radical burst from macrophages results in oxidative stress. These free radicals cause pulmonary inflammation if not countered by anti-oxidants. Therefore, in the present study cocrystals of isoniazid with four anti-oxidant hydroxy benzoic acids have been reported. Gallic acid, 2,3-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, and 3-hydroxybenzoic acid resulted in the formation of cocrystals when reacted with isoniazid. Cocrystal structure analysis confirmed the existence of pyridine-carboxylic acid synthon in the cocrystals of isoniazid with Gallic acid, 2,3-dihydroxybenzoic acid and 3-hydroxybenzoic acid. While cocrystal of 3,5-dihydroxybenzoic acid formed the pyridine-hydroxy group synthon. Other synthons of different graph sets are formed between hydrazide group of isoniazid and coformers involving Nsbnd H⋯O and Osbnd H⋯N bonds. All the cocrystals were in 1:1 stoichiometric ratio.

Mashhadi, Syed Muddassir Ali; Yunus, Uzma; Bhatti, Moazzam Hussain; Tahir, Muhammad Nawaz

2014-11-01

14

Polarizabilities and dipole moments of benzaldehyde, benzoic acid and oxalic acid in polar and nonpolar solvents  

Microsoft Academic Search

The purpose of this report is to calculate the orientation polarizability of benzaldehyde, benzoic acid and oxalic acid in polar and nonpolar solvents. The calculations are based on the knowledge of permanent dipole moment of the solutions. Other important physical quantities such as refractive index, density, specific volume, dielectric constant, molar polarization and molar refractivity are also calculated. Dipole moments

Nalan Tekin; Mustafa Cebe; Çelik Tar?mc?

2004-01-01

15

Antiherbivore prenylated benzoic acid derivatives from Piper kelleyi.  

PubMed

The known prenylated benzoic acid derivative 3-geranyl-4-hydroxy-5-(3?,3?-dimethylallyl)benzoic acid (1) and two new chromane natural products were isolated from the methanolic extract of the leaves of Piper kelleyi Tepe (Piperaceae), a midcanopy tropical shrub that grows in lower montane rain forests in Ecuador and Peru. Structure determination using 1D and 2D NMR analysis led to the structure of the chromene 2 and to the reassignment of the structure of cumanensic acid as 4, an isomeric chromene previously isolated from Piper gaudichaudianum. The structure and relative configuration of new chromane 3 was determined using 1D and 2D NMR spectroscopic analysis and was found to be racemic by ECD spectropolarimetry. The biological activity of 1-3 was evaluated against a lab colony of the generalist caterpillar Spodoptera exigua (Noctuidae), and low concentrations of 2 and 3 were found to significantly reduce fitness. Further consideration of the biosynthetic relationship of the three compounds led to the proposal that 1 is converted to 2 via an oxidative process, whereas 3 is produced through hetero-[4+2] dimerization of a quinone methide derived from the chromene 2. PMID:24422717

Jeffrey, Christopher S; Leonard, Michael D; Glassmire, Andrea E; Dodson, Craig D; Richards, Lora A; Kato, Massuo J; Dyer, Lee A

2014-01-24

16

Palladium-catalyzed chemoselective decarboxylative ortho acylation of benzoic acids with ?-oxocarboxylic acids.  

PubMed

Palladium-catalyzed chemoselective decarboxylative cross coupling of benzoic acids with ?-oxocarboxylic acids was realized via an arene sp(2) C-H functionalization process. This work represents the first example of transition-metal-catalyzed cross-coupling reactions with two acids acting in different roles. The synthetic utility of this method was confirmed by the synthesis of pitofenone, an antispasmodic used in the combined drug Spasmalgon. PMID:23721458

Miao, Jinmin; Ge, Haibo

2013-06-21

17

Role of Salicylic Acid and Benzoic Acid in Flowering of a Photoperiod-Insensitive Strain, Lemna paucicostata LP6 1  

PubMed Central

Lemna paucicostata LP6 does not normally flower when grown on basal Bonner-Devirian medium, but substantial flowering is obtained when 10 ?m salicylic acid (SA) or benzoic acid is added to the medium. Benzoic acid is somewhat more effective than SA, and the threshold level of both SA and benzoic acid required for flower initiation is reduced as the pH of the medium is lowered to 4.0. SA- or benzoic acid-induced flowering is enhanced in the simultaneous presence of 6-benzylaminopurine (BAP), although BAP per se does not influence flowering in strain LP6. Continuous presence of SA or benzoic acid in the culture medium is essential to obtain maximal flowering. A short-term treatment of the plants (for first 24 h) with 10 ?m SA or benzoic acid, followed by culture in the basal medium containing 1 ?m BAP can, however, stimulate profuse flowering. Benzoic acid is more effective than SA, and the effect is more pronounced at pH 4 than at 5.5. Thus, under these conditions, flowering is of an inductive nature. Experiments with [14C]SA and [14C]benzoic acid have provided evidence that at pH 4 there is relatively more uptake of benzoic acid than SA, thus leading to an increased flowering response. The data obtained from the experiments designed to study the mobility of [14C]SA and [14C]-benzoic acid from mother to daughter fronds indicate that there is virtually no mobility of SA or benzoic acid between fronds. PMID:16653155

Khurana, Jitendra P.; Cleland, Charles F.

1992-01-01

18

Salicylic Acid sans Aspirin in Animals and Man: Persistence in Fasting and Biosynthesis from Benzoic Acid  

PubMed Central

Salicylic acid (SA), which is central to defense mechanisms in plants and the principal metabolite of aspirin, occurs naturally in man with higher levels of SA and its urinary metabolite salicyluric acid (SU) in vegetarians overlapping with levels in patients on low-dose aspirin regimens. SA is widely distributed in animal blood. Fasting for major colorectal surgery did not cause disappearance of SA from plasma, even in patients following total proctocolectomy. A 13C6 benzoic acid load ingested by six volunteers led, between 8 and 16 h, to a median 33.9% labeling of urinary salicyluric acid. The overall contribution of benzoic acid (and its salts) to the turnover of circulating SA thus requires further assessment. However, that SA appears to be, at least partially, an endogenous compound should lead to reassessment of its role in human (and animal) pathophysiology. PMID:19053387

2008-01-01

19

Benzoic Acid Derivatives in a Hypogastrurid Collembolan: Temperature-Dependent Formation and Biological Significance as Deterrents  

Microsoft Academic Search

Two phenolic acids were identified in the collembolan Ceratophysella denticulata: 3-hydroxy-4,5 dimethoxy benzoic acid and 4-hydroxy-3,5-dimethoxybenzoic acid (syringic acid). These are localized on or in the integument of the springtail, in field-collected animals, in a ratio of 47:100 (v\\/v). Springtails kept under different temperature regimes showed differences in production and ratio of the benzoic acid derivatives. At 20°C, C. denticulata

Christine Bitzer; Gregor Brasse; Konrad Dettner; Stefan Schulz

2004-01-01

20

An optical test strip for the detection of benzoic acid in food.  

PubMed

Fabrication of a test strip for detection of benzoic acid was successfully implemented by immobilizing tyrosinase, phenol and 3-methyl-2-benzothiazolinone hydrazone (MBTH) onto filter paper using polystyrene as polymeric support. The sensing scheme was based on the decreasing intensity of the maroon colour of the test strip when introduced into benzoic acid solution. The test strip was characterized using optical fiber reflectance and has maximum reflectance at 375 nm. It has shown a highly reproducible measurement of benzoic acid with a calculated RSD of 0.47% (n = 10). The detection was optimized at pH 7. A linear response of the biosensor was obtained in 100 to 700 ppm of benzoic acid with a detection limit (LOD) of 73.6 ppm. At 1:1 ratio of benzoic acid to interfering substances, the main interfering substance is boric acid. The kinetic analyses show that, the inhibition of benzoic is competitive inhibitor and the inhibition constant (K(i)) is 52.9 ppm. The activity of immobilized tyrosinase, phenol, and MBTH in the test strip was fairly sustained during 20 days when stored at 3 °C. The developed test strip was used for detection of benzoic acid in food samples and was observed to have comparable results to the HPLC method, hence the developed test strip can be used as an alternative to HPLC in detecting benzoic acid in food products. PMID:22164018

Hamzah, Hairul Hisham; Yusof, Nor Azah; Salleh, Abu Bakar; Bakar, Fatimah Abu

2011-01-01

21

An Optical Test Strip for the Detection of Benzoic Acid in Food  

PubMed Central

Fabrication of a test strip for detection of benzoic acid was successfully implemented by immobilizing tyrosinase, phenol and 3-methyl-2-benzothiazolinone hydrazone (MBTH) onto filter paper using polystyrene as polymeric support. The sensing scheme was based on the decreasing intensity of the maroon colour of the test strip when introduced into benzoic acid solution. The test strip was characterized using optical fiber reflectance and has maximum reflectance at 375 nm. It has shown a highly reproducible measurement of benzoic acid with a calculated RSD of 0.47% (n = 10). The detection was optimized at pH 7. A linear response of the biosensor was obtained in 100 to 700 ppm of benzoic acid with a detection limit (LOD) of 73.6 ppm. At 1:1 ratio of benzoic acid to interfering substances, the main interfering substance is boric acid. The kinetic analyses show that, the inhibition of benzoic is competitive inhibitor and the inhibition constant (Ki) is 52.9 ppm. The activity of immobilized tyrosinase, phenol, and MBTH in the test strip was fairly sustained during 20 days when stored at 3 °C. The developed test strip was used for detection of benzoic acid in food samples and was observed to have comparable results to the HPLC method, hence the developed test strip can be used as an alternative to HPLC in detecting benzoic acid in food products. PMID:22164018

Hamzah, Hairul Hisham; Yusof, Nor Azah; Salleh, Abu Bakar; Bakar, Fatimah Abu

2011-01-01

22

Molecular design and synthesis of functional photothermopolymers from hydroxyl benzoic acids  

NASA Astrophysics Data System (ADS)

The most applicable hydroxyl benzoic acid monomers were optimized to synthesize the thermolysis-decarboxylation polymers according to the relative results of TG analysis of hydroxyl benzoic acids, their 13C-NMR spectra analyses and their quantum chemistry calculation with AB-INITIO method. On the basis of the empirical rule -- M/A value rule, while phenols with high M/A value and hydroxyl benzoic acids were both cocondensed with formaldehyde at proper ratio, the novolak resin with carboxyl groups used as a thermal imaging material could be obtained. In the presence of an acid catalyst, such as oxalic acid, a hydroxyl benzoic acid could be additionally polymerized with divinyl benzene (DVB) to synthesize another kind of polymer with not only carboxyl groups but also phenolic hydroxyl groups. The thermal imaging mechanisms of these polymers with carboxyl groups were discussed in the paper.

Tong, Xiao; Gu, Jiangnan; Wang, Liyuan; Zou, Yingquan; Yu, Shangxian

2000-06-01

23

Quantitative relationships between structure and solubility for some m- and p-substituted benzoic acids  

E-print Network

Benzoic Acids in Tetra- hydrofuran and in g-Dtoxane at 30 C. 22 Mole Ratio and Mole Fraction Solubilities of Benzoic Acids in ~-Dioxane and in Tetrahydrofuran . VI. Comparison cf the Evaporation and Titration Techniques for Determining the Solubility.... The amount of acid in a weighed portion of the saturated tetra- hydrofuran solutions was determined by evaporation of the solvent in a tared aluminum foil weighing dish. The concentration of the saturated p-dioxane solutions was deter- mined by titrating...

Idoux, John Paul

2012-06-07

24

A highly reversible and sensitive tyrosinase inhibition-based amperometric biosensor for benzoic acid monitoring  

Microsoft Academic Search

In this present work, a highly reversible and sensitive amperometric biosensor, based on the immobilization of tyrosinase (Tyro) by calcium carbonate nano-materials (nano-CaCO3), was applied for determination of food preservative, benzoic acid. The detection of benzoic acid was performed via its inhibiting action on the Tyro\\/nano-CaCO3 modified glassy carbon electrode. The effects of enzyme substrate type and substrate concentration on

Dan Shan; Qingbo Li; Huaiguo Xue; Serge Cosnier

2008-01-01

25

A study of rates of reaction of some substituted diphenyldiazomethanes and benzoic acid  

E-print Network

A STUDY OF RATES OF REACTION OF SOME SUBSTITUTED DIPHENYLDIAZ(METHANES AM) BENZOIC ACID A Dissertation By Ralph Fredrick Gilby, Jr. Approved as to style and content by; May 195^ A STOUT 'OF1 WffBS CF KEAC9XOI O f SOB ffliHfiiyi'f ilfl.... . . . . . . . . 11 II. Reaction Rate Constants (k) and Substituted Diphenyldiazomethanes . . . . 32 III. Determinations of the Reaction Rate of if,-Dimethoxydiphenyldiazomethane and Benzoic Acid................................. ... . %8 IV...

Gilby, Ralph Fredrick

2013-10-04

26

Anharmonic midinfrared vibrational spectra of benzoic acid monomer and dimer  

NASA Astrophysics Data System (ADS)

Anharmonic vibrational calculations for the benzoic acid monomer and dimer in the mid-IR regime (500-1800cm-1) are reported. Harmonic frequencies and intensities are obtained at the DFT/B3LYP level of theory employing D95(d,p) and cc-pVTZ basis sets. Anharmonic corrections obtained from standard perturbation theory lead to redshifts of 1%-3%. In almost all cases, the resulting frequencies deviate by less than 1% from previous measurements [Bakker et al., J. Chem. Phys. 119, 11180 (2003)]. Calculated intensities are in qualitative agreement with the absorption experiment, with the cc-pVTZ values being superior to the D95(d,p) ones for a few modes of the dimer. The antisymmetric out-of-plane bending mode of the dimer, which is strongly blueshifted with respect to the monomer frequency, represents a remarkable exception: The harmonic frequencies obtained for the two basis sets differ notably from each other, and the anharmonically corrected frequencies deviate from the experimental value by 8% [D95(d,p)] or 3% (cc-pVTZ). Nonperturbative calculations in reduced dimensionality reveal that the relatively small total anharmonic shift (few tens of cm-1) comprises of partly much larger contributions (few hundreds of cm-1) which are mostly canceling each other. Many of the individual anharmonic couplings are beyond the validity of second-order perturbation theory based on cubic and semidiagonal quartic force constants only. This emphasizes the need for high-dimensional, nonperturbative anharmonic calculations at high quantum-chemical level when accurate frequencies of H-atom vibrations in double hydrogen bonds are sought for.

Antony, Jens; von Helden, Gert; Meijer, Gerard; Schmidt, Burkhard

2005-07-01

27

A study of rates of reaction of some substituted benzoic acids and diphenyldiazomethane  

E-print Network

. , Inc. , New York, N. Y. ~ 1940~ p. 185. (2). H. H. Jaffe'~ Chem. Revs. ~ ~3~ 191 (1953). (3). H. Staudinger and A. Gaule~ Ber. ~ Q~ 1897 (1916). (4). J. F. Norris and W. H. Strain, J. Am. Chem. Soc. , +7, 187 (1935). with several substituted benzoic...-isapropylbenzoic, p-tert-butylbenzoicp m-msthaxy- benzoic, 3, 5-dimethylbenzoic) the followi le, 'iod w. ta zt . ; The DDM was prepared to give an OD of appraximately 0, 600. The acid concentration was 0. 0600 Lz, A pipst was used to transfer 25 ml. of benzoic...

Westmoreland, John Sherman

2012-06-07

28

A limited LCA of bio-adipic acid: Manufacturing the nylon-6,6 precursor adipic acid using the benzoic acid degradation pathway from different feedstocks  

Microsoft Academic Search

A limited life cycle assessment (LCA) was performed on a combined biological and chemical process for the production of adipic acid, which was compared to the traditional petrochemical process. The LCA comprises the biological conversion of the aromatic feedstocks benzoic acid, impure aromatics, toluene, or phenol from lignin to cis, cis-muconic acid, which is subsequently converted to adipic acid through

Duuren van J. B. J. H; B. Brehmer; A. E. Mars; G. Eggink; V. A. P. Martins dos Santos; J. P. M. Sanders

2011-01-01

29

Augmenting the activity of antifungal agents against aspergilli using structural analogues of benzoic acid as chemosensitizing agents  

Microsoft Academic Search

A number of benzoic acid analogues showed antifungal activity against strains of Aspergillus flavus, Aspergillus fumigatus and Aspergillus terreus, causative agents of human aspergillosis, in in vitro bioassays. Structure–activity analysis revealed that antifungal activities of benzoic and gallic acids were increased by addition of a methyl, methoxyl or chloro group at position 4 of the aromatic ring, or by esterification

Jong H. Kim; Bruce C. Campbell; Noreen Mahoney; Kathleen L. Chan; Russell J. Molyneux; Arunmozhi Balajee

2010-01-01

30

The effect of benzoic acid or its ethyl ester on rumen fermentation parameters  

E-print Network

The effect of benzoic acid or its ethyl ester on rumen fermentation parameters J Nousiainen Valio be used as mould and yeast inhibitors in silage additives to improve the aerobic stability of silage response of BA or its ethyl ester (EB) on the rumen fermentation parameters in the continuous culture

Paris-Sud XI, Université de

31

40 CFR 721.10020 - Benzoic acid, 5-amino-2-chloro-, 1,1-dimethyl-2-oxo-2-(2-propenyloxy) ethyl ester.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Benzoic acid, 5-amino-2-chloro-, 1,1-dimethyl-2-oxo-2...Substances § 721.10020 Benzoic acid, 5-amino-2-chloro-, 1,1-dimethyl-2-oxo-2...substance identified as benzoic acid, 5-amino-2-chloro-,...

2010-07-01

32

Conversions of 2-(2Oxo Cyclohexylcarbonyl)Benzoic Acid Derivatives to Pyrazolo[, , , , , , , , , , ]Isoindole and Pyrimidine Rings  

Microsoft Academic Search

Phtalic acid derivative of o-methylcarboxybenzoylchloride readily acylates N(1-cyclohexenyl) morpholine and is likely to acylate other enamines along the classic path to 1,3-diketones. It is a convenient route towards o-(1-(1,3-diketone)) derivatives of benzoic acid, which are precursors of o-(heteroaryl)-benzoic acids. Further conversions with hydrazines and amidines lead to pyrazolo[, , , , , , , , , , ]isoindole and pyrimidine

J. G. Wolf; Z. V. Voitenko; O. A. Pokholenko; I. S. Kondratov; V. O. Kovtunenko; C. André

2005-01-01

33

Tyrosinase inhibitory effect of benzoic acid derivatives and their structure-activity relationships.  

PubMed

A series of benzoic acid derivatives 1-10 have been synthesised by two different methods. Compounds 1-6 were synthesised by a facile procedure for esterification using N,N'-dicyclohexylcarbodiimide (DCC) as a coupling agent, methylene chloride as a solvent system and dimethylaminopyridine (DMAP). While 7-10 were synthesised by converting benzoic acid into benzoyl chloride by treating with thionyl chloride in the presence of benzene and performing a further reaction with amine in dried benzene. The structures of all the synthesised derivatives of benzoic acid (1-10) were assigned on the basis of extensive NMR studies. All of them showed inhibitory potential against tyrosinase. Among them, compound 7 was found to be the most potent (1.09 ?M) when compared with the standard tyrosinase inhibitors of kojic acid (16.67 ?M) and L-mimosine (3.68 ?M). Finally in this paper, we have discussed the structure-activity relationships of the synthesised molecules. PMID:20476840

Khan, Sher Bahadar; Hassan Khan, Mahmud Tareq; Jang, Eui Sung; Akhtar, Kalsoom; Seo, Jongchul; Han, Haksoo

2010-12-01

34

Aneroid Bomb Calorimeter for Determining the Heat of Combustion of Thermochemical Standard Benzoic Acid  

Microsoft Academic Search

An electrically calibrated bomb calorimeter is described which has no stirred water, and is mounted in an evacuated outer jacket. Its departures from the ideal are investigated. The heat of combustion of samples from a batch of specially pure benzoic acid is found to be 26431\\\\cdot7 J\\/g under `standard bomb conditions', with an estimated standard error of 2.2 J\\/g. This

A. R. Meetham; J. A. Nicholls

1960-01-01

35

Acquisition of the ability for Rhodopseudomonas palustris to degrade chlorinated benzoic acids as the sole carbon source  

E-print Network

Acquisition of the ability for Rhodopseudomonas palustris to degrade chlorinated benzoic acids October 2001 First published online 29 October 2001 Abstract Three strains of Rhodopseudomonas palustris enrichment; 3-Chlorobenzoate; Adaptation; Rhodopseudomonas palustris 1. Introduction Anoxic mineralization

Forney, Larry J.

36

Potentiometric Responses of Ion-Selective Electrodes Doped with Diureidocalix[4]arene towards Un-dissociated Benzoic Acid  

PubMed Central

Diureidocalix[4]arene have been applied as new ionophore in liquid membrane electrode (ISE) sensitive towards un-dissociated benzoic acid. The electrode demonstrated response towards benzoic acid with the detection limit 2.0 × 10-4 M which is sufficient for the determination of benzoic acid added to beverages as preservative in milimolar concentration. The selectivity coefficients measured by the matched potential method (MPM) showed its good selectivity against common anions present in drink samples. All measurements were made in presence of 1.0 × 10-2 M NaHSO4 pH 3.0 in order to reduce the influence of OH-. The applicability of diureidocalix[4]arene incorporated ISE has been checked by recovery test of benzoic acid in the presence of artificial drink matrix and by standard addition method.

Krajewska, Agnieszka; Lhotak, Pavel; Radecka, Hanna

2007-01-01

37

Accurate prediction of the toxicity of benzoic acid compounds in mice via oral without using any computer codes.  

PubMed

Most of benzoic acid derivatives are toxic, which may cause serious public health and environmental problems. Two novel simple and reliable models are introduced for desk calculations of the toxicity of benzoic acid compounds in mice via oral LD(50) with more reliance on their answers as one could attach to the more complex outputs. They require only elemental composition and molecular fragments without using any computer codes. The first model is based on only the number of carbon and hydrogen atoms, which can be improved by several molecular fragments in the second model. For 57 benzoic compounds, where the computed results of quantitative structure-toxicity relationship (QSTR) were recently reported, the predicted results of two simple models of present method are more reliable than QSTR computations. The present simple method is also tested with further 324 benzoic acid compounds including complex molecular structures, which confirm good forecasting ability of the second model. PMID:22959133

Keshavarz, Mohammad Hossein; Gharagheizi, Farhad; Shokrolahi, Arash; Zakinejad, Sajjad

2012-10-30

38

Crystal Structure of CYP199A2, a Para-Substituted Benzoic Acid Oxidizing Cytochrome P450 from Rhodopseudomonas palustris  

Microsoft Academic Search

CYP199A2, a cytochrome P450 enzyme from Rhodopseudomonas palustris, oxidatively demethylates 4-methoxybenzoic acid to 4-hydroxybenzoic acid. 4-Ethylbenzoic acid is converted to a mixture of predominantly 4-(1-hydroxyethyl)-benzoic acid and 4-vinylbenzoic acid, the latter being a rare example of CC bond dehydrogenation of an unbranched alkyl group. The crystal structure of CYP199A2 has been determined at 2.0-Å resolution. The enzyme has the common

Stephen G. Bell; Feng Xu; Ian Forward; Mark Bartlam; Zihe Rao; Luet-Lok Wong

2008-01-01

39

The contribution of solvent drag to the intestinal absorption of the acidic drugs benzoic acid and salicylic acid from the jejunum of the rat  

Microsoft Academic Search

1.Jejunal loops of anaesthetized rats were perfused with hypotonic, isotonic and hypertonic buffered solutions containing 14C-labelled benzoic acid and salicylic acid at pH 6.2 and 2.2. The blood flow of the loop was maintained at an intermediate rate (0.78–0.97 ml min-1 g-1). The water net flux was determined by polyethylene glycol as non-absorbable marker and amounted up to +31 or-27

H. Ochsenfahrt; D. Winne

1974-01-01

40

Ordered cleavage of myeloperoxidase ester bonds releases active site heme leading to inactivation of myeloperoxidase by benzoic acid hydrazide analogs.  

PubMed

Myeloperoxidase (MPO) catalyzes the breakdown of hydrogen peroxide and the formation of the potent oxidant hypochlorous acid. We present the application of the fluorogenic peroxidase substrate 10-acetyl-3,7-dihydroxyphenoxazine (ADHP) in steady-state and transient kinetic studies of MPO function. Using initial kinetic parameters for the MPO system, we characterized under the same conditions a number of gold standards for MPO inhibition, namely 4-amino benzoic acid hydrazide (4-ABAH), isoniazid and NaN3 before expanding our focus to isomers of 4-ABAH and benzoic acid hydrazide analogs. We determined that in the presence of hydrogen peroxide that 4-ABAH and its isomer 2-ABAH are both slow-tight binding inhibitors of MPO requiring at least two steps, whereas NaN3 and isoniazid-based inhibition has a single observable step. We also determined that MPO inhibition by benzoic acid hydrazide and 4-(trifluoromethyl) benzoic acid hydrazide was due to hydrolysis of the ester bond between MPO heavy chain Glu 242 residue and the heme pyrrole A ring, freeing the light chain and heme b fragment from the larger remaining MPO heavy chain. This new mechanism would essentially indicate that the benzoic acid hydrazide analogs impart inhibition through initial ejection of the heme catalytic moiety without prior loss of the active site iron. PMID:24632143

Huang, Jiansheng; Smith, Forrest; Panizzi, Peter

2014-04-15

41

Docking of oxalyl aryl amino benzoic acid derivatives into PTP1B  

PubMed Central

Protein Tyrosine Phosphatases (PTPs) that function as negative regulators of the insulin signaling cascade have been identified as novel targets for the therapeutic enhancement of insulin action in insulin resistant disease states. Reducing Protein Tyrosine Phosphatase1B (PTP1B) abundance not only enhances insulin sensitivity and improves glucose metabolism but also protects against obesity induced by high fat feeding. PTP1B inhibitors such as Formylchromone derivatives, 1, 2-Naphthoquinone derivatives and Oxalyl aryl amino benzoic derivatives may eventually find an important clinical role as insulin sensitizers in the management of Type-II Diabetes and metabolic syndrome. We have carried out docking of modified oxalyl aryl amino benzoic acid derivatives into three dimensional structure of PTP1B using BioMed CAChe 6.1. These compounds exhibit good selectivity for PTP1B over most of phosphatases in selectivity panel such as SHP-2, LAR, CD45 and TCPTP found in literature. This series of compounds identified the amino acid residues such as Gly220 and Arg221 are important for achieving specificity via H-bonding interactions. Lipophilic side chain of methionine in modified oxalyl aryl amino benzoic acid derivative [1b (a2, b2, c1, d)] lies in closer vicinity of hydrophobic region of protein consisted of Meth258 and Phe52 in comparison to active ligand. Docking Score in [1b (a2, b2, c1, d)] is -131.740Kcal/mol much better than active ligand score -98.584Kcal/mol. This information can be exploited to design PTP1B specific inhibitors. PMID:19238234

Verma, Neelam; Mittal, Minakshi; Verma, Raman kumar

2008-01-01

42

Docking of oxalyl aryl amino benzoic acid derivatives into PTP1B.  

PubMed

Protein Tyrosine Phosphatases (PTPs) that function as negative regulators of the insulin signaling cascade have been identified as novel targets for the therapeutic enhancement of insulin action in insulin resistant disease states. Reducing Protein Tyrosine Phosphatase1B (PTP1B) abundance not only enhances insulin sensitivity and improves glucose metabolism but also protects against obesity induced by high fat feeding. PTP1B inhibitors such as Formylchromone derivatives, 1, 2-Naphthoquinone derivatives and Oxalyl aryl amino benzoic derivatives may eventually find an important clinical role as insulin sensitizers in the management of Type-II Diabetes and metabolic syndrome. We have carried out docking of modified oxalyl aryl amino benzoic acid derivatives into three dimensional structure of PTP1B using BioMed CAChe 6.1. These compounds exhibit good selectivity for PTP1B over most of phosphatases in selectivity panel such as SHP-2, LAR, CD45 and TCPTP found in literature. This series of compounds identified the amino acid residues such as Gly220 and Arg221 are important for achieving specificity via H-bonding interactions. Lipophilic side chain of methionine in modified oxalyl aryl amino benzoic acid derivative [1b (a2, b2, c1, d)] lies in closer vicinity of hydrophobic region of protein consisted of Meth258 and Phe52 in comparison to active ligand. Docking Score in [1b (a2, b2, c1, d)] is -131.740Kcal/mol much better than active ligand score -98.584Kcal/mol. This information can be exploited to design PTP1B specific inhibitors. PMID:19238234

Verma, Neelam; Mittal, Minakshi; Verma, Raman Kumar

2008-01-01

43

Antihepatotoxic activity of p-methoxy benzoic acid from Capparis spinosa.  

PubMed

p-Methoxy benzoic acid isolated from the methanolic soluble fraction of the aqueous extract of Capparis spinosa L. (Capparidaceae) was found to possess significant antihepatotoxic activity against carbontetrachloride and paracetamol induced hepatotoxicity in vivo and thioacetamide and galactosamine induced hepatotoxicity in isolated rat hepatocytes, using in vitro technique. The compound was characterized through physicochemical and spectral studies. Isolation, identification and antihepatotoxic activity of the compound is reported for the first time in the plant. HPTLC analysis of methanol soluble fraction indicated that the compound constitutes 33% w/w of the active fraction. PMID:10433476

Gadgoli, C; Mishra, S H

1999-08-01

44

Complex formation of native and hydroxypropylated cyclodextrins with benzoic acid in aqueous solution: Volumetric and 1H NMR study  

NASA Astrophysics Data System (ADS)

Novel data on complexation of benzoic acid by parent and hydroxypropylated cyclodextrins were obtained by densimetry and 1H NMR. Formation of 1:1 inclusion complexes was detected in most cases with the exception of hydroxypropyl-?-cyclodextrin, which is able to form 1:2 complexes. The data demonstrated penetration of carboxylic group of benzoic acid inside macrocyclic cavity, its insertion into ?-cyclodextrin cavity being deeper. Binding constants and volumes of transfer were calculated and analyzed in terms of influence of cyclodextrin structure on binding mode and driving forces of interaction as well as on the complex stability.

Terekhova, Irina; Ko?bia?, Malgorzata; Kumeev, Roman; Gierycz, Pawe?

2011-10-01

45

DFT and ab initio study of structure of dyes derived from 2-hydroxy and 2,4-dihydroxy benzoic acids  

NASA Astrophysics Data System (ADS)

We present a detailed analysis of the structural, infrared spectra and visible spectra of a series of azo dyes preparation of salicylic acid and 2,4-dihydroxy benzoic acid derivatives as the coupling component. The preparation of these azo dyes with salicylic acid and 2,4-dihydroxy benzoic acid derivatives (salicylic acid, methyl salicylate, ethyl salicylate, butyl salicylate, methyl 2,4-dihydroxy benzoate, ethyl 2,4-dihydroxy benzoate, salicylaldehyde, salicylamide, 2,4-dihydroxy benzamide, salicylaldoxime) have been investigated theoretically by performing HF and DFT levels of theory using the standard 6-31G* basis set. The optimized geometries and calculated vibrational frequencies are evaluated via comparison with experimental values. The vibrational spectral data obtained from solid phase FT-IR spectra are assigned modes based on the results of the theoretical calculations. The observed spectra are found to be in good agreement with the calculations.

Dabbagh, Hossein A.; Teimouri, Abbas; Najafi Chermahini, Alireza; Shahraki, Maryam

2008-02-01

46

Oxidation of benzaldehydes to benzoic acid derivatives by three Desulfovibrio strains.  

PubMed Central

Desulfovibrio vulgaris Marburg, "Desulfovibrio simplex" XVI, and Desulfovibrio sp. strain MP47 used benzaldehydes such as vanillin, 3,4,5-trimethoxybenzaldehyde, protocatechualdehyde, syringaldehyde, p-anisaldehyde, p-hydroxybenzaldehyde, and 2-methoxybenzaldehyde as electron donors for sulfate reduction and carbon dioxide and/or components of yeast extract as carbon sources for cell synthesis. The aldehydes were oxidized to their corresponding benzoic acids. The three sulfate reducers oxidized up to 7 mM vanillin and up to 4 mM p-anisaldehyde. Higher concentrations of vanillin or p-anisaldehyde were toxic. In addition, pyridoxal hydrochloride and o-vanillin served as electron donors for sulfate reduction. Salicylaldehyde, pyridine-2-aldehyde, pyridine-4-aldehyde, and 4-hydroxy-3-methoxybenzylalcohol were not oxidized. No molecular hydrogen was detected in the gas phase. The oxidized aldehydes were not further degraded. PMID:2389937

Zellner, G; Kneifel, H; Winter, J

1990-01-01

47

Thermal and spectroscopic characterization of Mg(II) complexes of nitro-substituted benzoic acids  

Microsoft Academic Search

The Mg(II) complexes of the nitro-substituted benzoic acids have been investigated by thermal and spectroscopic methods. Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC), and other spectroscopic methods have been used to investigate the thermal behavior and structure of the compounds [Mg(H2O)6](4-nba)2·2H2O 1, [Mg(H2O)6](3-nba)2·2H2O 2, [Mg(H2O)6](2-nba)2·2H2O 3 (4-nba=para-nitrobenzoate; 3-nba=meta-nitrobenzoate; and 2-nba=ortho-nitrobenzoate). All the complexes are formulated as consisting

B. R. Srinivasan; Sarvesh C. Sawant

2003-01-01

48

Urine acidification and mineral metabolism in growing pigs fed diets supplemented with dietary methionine and benzoic acid  

Microsoft Academic Search

Benzoic acid (BA) reduces pH of urine and thereby reduces the emission of ammonia and possibly also odorous sulphur-compounds from slurry. The effect of BA on mineral metabolism in growing pigs is not clear. The objective was therefore to study the effect of BA and methionine (Met) as a sulphur (S) source in diets for pigs on urine acidification and

J. V. Nørgaard; J. A. Fernández; J. Eriksen; O. H. Olsen; D. Carlson; H. D. Poulsen

2010-01-01

49

A platinum(II) complex bearing deprotonated 2-(diphenylphosphino)benzoic acid for superior phosphorescence of monomers.  

PubMed

The (ppy)-based Pt(II) complex (Pt-1) with deprotonated 2-(diphenylphosphino)benzoic acid as an anionic ligand displays phosphorescence of monomers with a remarkably higher quantum yield than that of the corresponding iridium complex (Ir-1). A prototype OLED using Pt-1 exhibits high performance with an external quantum efficiency of 4.93%. PMID:24718420

Zhang, Bin; Zhang, Lina; Liu, Chunmei; Zhu, Yanyan; Tang, Mingsheng; Du, Chenxia; Song, Maoping

2014-06-01

50

Chlorine-free Friedel–Crafts acylation of benzene with benzoic anhydride on insoluble heteropoly acid catalyst  

Microsoft Academic Search

Friedel–Crafts acylation of benzene (BEN) with benzoic anhydride (BAN) to produce benzophenone (BPH) was studied over various ion-exchanged heteropoly acids (HPA). No metal chloride such as AlCl3 was used as a catalyst. No acid chloride was used as an acylating agent. Therefore, this reaction could be a model of chlorine-free fine chemical synthesis process. As the activity of benzene was

Tomohiko Tagawa; Junichi Amemiya; Shigeo Goto

2004-01-01

51

Effect of the chemical specificity of benzoic acid and its analogs on osmotic fragility in erythrocytes of Sprague-Dawley rats in vitro.  

PubMed

We examined the chemical specificity of benzoic (benzene-carboxylic) acid and its derivatives in increasing osmotic fragility (OF) in rat red blood cells (RBCs) in vitro. Benzoic acid increased the OF in the rat RBCs in a dose-dependent manner. Replacement of the carboxylic group with a phosphoric group also increased the OF in RBCs, whereas substitution of the carboxylic group by a sulfonic, amide or hydroxy group did not affect the OF. Replacement of the benzene nucleus with a cyclohexane ring or a straight hydrocarbon chain with six carbons resulted in a greater increase in OF than that induced by benzoic acid. Introduction of a methyl group, chloride or bromide at the m- and p-positions of the benzene ring considerably enhanced the increase in OF induced by benzoic acid. Substitution of the amino and hydroxy group at the m- and p- positions abolished the increase in OF induced by benzoic acid. The introduction of these elements at the o-position showed an almost equal increase in OF as that observed for benzoic acid. A molecule of benzoic acid is composed of both hydrophilic (carboxylic group) and hydrophobic (benzene ring) components. Replacement of the hydrophilic component changed the balance formed between hydrophobic and hydrophilic components in the moiety, resulting alterations to its interaction with the RBC membrane. The size, form and elements introduced into the benzene ring also affected its affinity to the cell membrane, and changed the osmotic resistance in rat RBCs. PMID:23376564

Mineo, Hitoshi; Ogita, Ai; Kanayama, Nozomi; Kawagishi, Mai; Sato, Eiko; Yamamoto, Nodoka; Arai, Kohei; Izawa, Masa-aki

2013-02-28

52

Dietary Supplementation of Benzoic Acid and Essential Oil Compounds Affects Buffering Capacity of the Feeds, Performance of Turkey Poults and Their Antioxidant Status, pH in the Digestive Tract, Intestinal Microbiota and Morphology  

PubMed Central

Three trials were conducted to evaluate the effect of supplementation of a basal diet with benzoic acid or thymol or a mixture of essential oil blends (MEO) or a combination of benzoic acid with MEO (BMEO) on growth performance of turkey poults. Control groups were fed a basal diet. In trial 1, benzoic acid was supplied at levels of 300 and 1,000 mg/kg. In trial 2, thymol or the MEO were supplied at levels of 30 mg/kg. In trial 3, the combination of benzoic acid with MEO was evaluated. Benzoic acid, MEO and BMEO improved performance, increased lactic acid bacteria populations and decreased coliform bacteria in the caeca. Thymol, MEO and BMEO improved antioxidant status of turkeys. Benzoic acid and BMEO reduced the buffering capacity compared to control feed and the pH values of the caecal content. Benzoic acid and EOs may be suggested as an effective alternative to AGP in turkeys. PMID:25049947

Giannenas, I.; Papaneophytou, C. P.; Tsalie, E.; Pappas, I.; Triantafillou, E.; Tontis, D.; Kontopidis, G. A.

2014-01-01

53

Summer and winter variations of dicarboxylic acids, fatty acids and benzoic acid in PM2.5 in Pearl Delta River Region, China  

NASA Astrophysics Data System (ADS)

Ground-based PM2.5 samples collected at four different sites in Pearl River Delta region (PRD) during winter and summer (from 14 December 2006 to 28 January 2007 in winter and from 4 July to 9 August 2007 in summer) were analyzed for 30 water-soluble organic species, including dicarboxylic acids, ketocarboxylic acids and dicarbonyls, nine fatty acids, and benzoic acid. Molecular distributions of dicarboxylic acids demonstrated that oxalic acid (C2) was the most abundant species followed by phthalic acid (Ph) in PRD region. The concentrations of total dicarboxylic acids ranged from 99 to 1340 ng m-3, with an average of 438 ± 267 ng m-3 in PRD. The concentrations of total ketocarboxylic acids ranged from 0.6 to 207 ng m-3 (43 ± 48 ng m-3 on average) while the concentrations of total ?-dicarbonyls, including glyoxal and methylglyoxal, ranged from 0.2 to 89 ng m-3, with an average of 11 ± 18 ng m-3 in PRD. The total quantified water-soluble compounds (TQWOC) (organic carbon) accounted for 3.4 ± 2.2% of OC and 14.3 ± 10.3% of water-soluble OC (WSOC). Hexadecanoic acid (C16:0), octadecanoic acid (C18:0) and oleic acid (C18:1) were the three most abundant fatty acids in PRD. The distributions of fatty acids were characterized by a strong even carbon number predominance with a maximum (Cmax) at hexadecanoic acid (C16:0). Ratio of C18:1 to C18:0 acts as an indicator for aerosol aging. In PRD, an average of C18:1/C18:0 ratio was 0.53 ± 0.39, suggesting an enhanced photochemical degradation of unsaturated fatty acid. Moreover, the concentrations of benzoic acid ranged from 84 to 306 ng m-3, (165 ± 48 ng m-3 on average), which can be emitted as primary pollutant from motor vehicles exhaust, or formed from photochemical degradation of aromatic hydrocarbons. Seasonal variations of the organic specie concentrations were found in the four sampling cities. Higher concentrations of TQWOC were observed in winter (598 ± 321 ng m-3) than in summer (372 ± 215 ng m-3). However, the abundances of TQWOC in OC mass were higher in summer (0.9-12.4%, 4.5 ± 2.7% on average) than in winter (1.1-5.7, 2.5 ± 1.2% on average), being consistent with enhanced secondary production of dicarboxylic acids in warmer weather. Spatial variations of water-soluble dicarboxylic acids were characterized by higher concentrations in Hong Kong and lower concentrations in Guangzhou (GZ)/Zhaoqing (ZQ) during winter whereas the highest concentrations were observed in GZ/ZQ during summer. These spatial and seasonal distributions are consistent with photochemical production and the subsequent accumulation under different meteorological conditions.

Ho, K. F.; Ho, S. S. H.; Lee, S. C.; Kawamura, K.; Zou, S. C.; Cao, J. J.; Xu, H. M.

2011-03-01

54

A limited LCA of bio-adipic acid: manufacturing the nylon-6,6 precursor adipic acid using the benzoic acid degradation pathway from different feedstocks.  

PubMed

A limited life cycle assessment (LCA) was performed on a combined biological and chemical process for the production of adipic acid, which was compared to the traditional petrochemical process. The LCA comprises the biological conversion of the aromatic feedstocks benzoic acid, impure aromatics, toluene, or phenol from lignin to cis, cis-muconic acid, which is subsequently converted to adipic acid through hydrogenation. Apart from the impact of usage of petrochemical and biomass-based feedstocks, the environmental impact of the final concentration of cis, cis-muconic acid in the fermentation broth was studied using 1.85% and 4.26% cis, cis-muconic acid. The LCA focused on the cumulative energy demand (CED), cumulative exergy demand (CExD), and the CO(2) equivalent (CO(2) eq) emission, with CO(2) and N(2) O measured separately. The highest calculated reduction potential of CED and CExD were achieved using phenol, which reduced the CED by 29% and 57% with 1.85% and 4.26% cis, cis-muconic acid, respectively. A decrease in the CO(2) eq emission was especially achieved when the N(2) O emission in the combined biological and chemical process was restricted. At 4.26% cis, cis-muconic acid, the different carbon backbone feedstocks contributed to an optimized reduction of CO(2) eq emissions ranging from 14.0 to 17.4 ton CO(2) eq/ton adipic acid. The bulk of the bioprocessing energy intensity is attributed to the hydrogenation reactor, which has a high environmental impact and a direct relationship with the product concentration in the broth. PMID:21328320

van Duuren, J B J H; Brehmer, B; Mars, A E; Eggink, G; Dos Santos, V A P Martins; Sanders, J P M

2011-06-01

55

Pressure dependence of the dissociation of acetic, benzoic, mandelic and succinic acids at 298.15 K  

Microsoft Academic Search

Dissociation constants for acetic, benzoic, mandelic and succinic acids have been measured at 298.15K as a function of pressure up to 138.8MPa. The spectrophotometric technique using Bromocresol Green as the optical indicator was employed up to ionic strength of 0.03molkg?1 in aqueous solution. Thermodynamic dissociation constants were calculated with the Davies activity coefficient equation. The pressure dependences of the ionization

Anil Kumar

2005-01-01

56

Thioureides of 2-(phenoxymethyl)benzoic acid 4-R substituted: A novel class of anti-parasitic compounds  

Microsoft Academic Search

Fifty members of a novel class of antimicrobial compounds, 2-(4-R-phenoxymethyl)benzoic acid thioureides, were synthesized and characterized with respect to their activities against three parasites of human relevance, namely the protozoa Giardia lamblia and Toxoplasma gondii, and the larval (metacestode) stage of the tapeworm Echinococcus multilocularis. To determine the selective toxicity of these compounds, the human colon cancer cell line Caco2

Joachim Müller; Carmen Limban; Britta Stadelmann; Alexandru Vasile Missir; Ileana Cornelia Chirita; Mariana Carmen Chifiriuc; George Mihai Nitulescu; Andrew Hemphill

2009-01-01

57

Adsorption of Benzoic Acid in Aqueous Solution by Bagasse Fly Ash  

NASA Astrophysics Data System (ADS)

This paper reports the studies on the benzoic acid (BA) onto bagasse fly ash (BFA) was studied in aqueous solution in a batch system. Physico-chemical properties including surface area, surface texture of the GAC before and after BA adsorption onto BFA were analysed using X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The optimum initial pH for the adsorption of BA was found to be 5.56. The adsorbent dose was 10 g/l for BFA and the equilibrium time 8 h of reaction. Pseudo first and second order models were used to find the adsorption kinetics. It was found that intraparticle diffusion played important role in the adsorption mechanisms of BA and the adsorption kinetics followed pseudo-second order kinetic model rather than the pseudo first order kinetic model. Isotherm data were generated for BA solution having initial concentrations of BA in the range of 10-200 mg/l for the BFA dosage of 10 g/l at temperatures of 288, 303, and 318 K. The adsorption of BA onto BFA was favorably influenced by an increase in temperature. Equilibrium data were well represented by the Redlich-Peterson isotherm model. Values of the change in entropy ( ?S 0), heat of adsorption ( ?H 0) for adsorption of BA on BFA was found to be 120.10 and 19.61 kJ/mol respectively. The adsorption of BA onto BFA was an endothermic reaction. Desorption of BA from BFA was studied by various solvents method. Acetic acid was found to be a better eluant for desorption of BA with a maximum desorption efficiency of 55.2 %. Owing to its heating value, spent BFA can be used as a co-fuel for the production of heat in boiler furnaces.

Suresh, S.

2012-09-01

58

Heterogeneous photo-Fenton oxidation of benzoic acid in water: Effect of operating conditions, reaction by-products and coupling with biological treatment  

Microsoft Academic Search

The heterogeneous photo-Fenton oxidation of benzoic acid, a precursor of several organic pollutants found in agro-industrial effluents, was studied in model aqueous solutions. UVA irradiation was provided by a 125W medium pressure mercury lamp, while a nanocomposite material of crystalline iron oxides supported over mesostructured SBA-15 was used as the catalyst. Experiments were conducted at benzoic acid initial concentrations between

M. Isabel Pariente; Fernando Martínez; Juan Antonio Melero; Juan Ángel Botas; Theodora Velegraki; Nikolaos P. Xekoukoulotakis; Dionissios Mantzavinos

2008-01-01

59

A high performance liquid chromatography system for quantification of hydroxyl radical formation by determination of dihydroxy benzoic acids.  

PubMed

The hypoxanthine/xanthine oxidase enzyme system is known to produce the superoxide ion and hydrogen peroxide during the hydroxylation of hypoxanthine via xanthine to uric acid. When chelated iron is included in this system, superoxide reduces iron (III) to iron(II) and the iron(II)-chelate further reacts with hydrogen peroxide to form the highly reactive hydroxyl radical. Because of the limitations of colourimetric and spectrophotometric techniques by which, to date, the mechanisms of hydroxyl radical formation in the hypoxanthine/xanthine oxidase system have been monitored, a high performance liquid chromatography method utilizing the ion-pair reagent tetrabutylammonium hydroxide and salicylic acid as an aromatic probe for quantification of hydroxyl radical formation was set up. In the hypoxanthine/xanthine oxidase system the major products of hydroxyl radical attack on salicylic acid were 2,5-dihydroxy benzoic acid and 2,3-dihydroxy benzoic acid in the approximate ratio of 5:1. That the hydroxyl radical is involved in the hydroxylation of salicylic acid in this system was demonstrated by the potency especially of dimethyl sulphoxide, butanol and ethanol as scavengers. Phytic acid, which is considered to be an important protective dietary constituent against colorectal cancer, inhibited hydroxylation of salicylic acid at a concentration one order of magnitude lower than the classical scavengers, but was only effective in the absence of EDTA. The method has been applied to the study of free radical generation in faeces, and preliminary results indicate that the faecal flora are able to produce reactive oxygen species in abundance. PMID:8894560

Owen, R W; Wimonwatwatee, T; Spiegelhalder, B; Bartsch, H

1996-08-01

60

Comparison of salicylic acid, benzoic acid and p-hydroxybenzoic acid for their ability to induce flowering in Lemna Gibba G3  

SciTech Connect

The long-day plant Lemna gibba G3 fails to flower under continuous light on NH/sub 4//sup +/-free 0.5 H medium. This inhibition is completely reversed by 10 ..mu..M salicyclic acid (SA) or 32 ..mu..M benzoic acid (BA). By contrast, p-hydroxybenzoic acid (p-OH-BA) has virtually no effect on flowering at levels as high as 320 ..mu..M. Uptake rates for the three compounds are comparable. Competition studies using /sup 14/C-SA indicate that, compared to SA, BA is about 10-fold less effective and p-OH-BA is nearly 100-fold less effective in competing against /sup 14/C-SA uptake. Both the effectiveness of SA for inducing flowering and the uptake of /sup 14/C-SA are substantially increased as the pH of the medium is lowered from 8 to 4.5. Under a nitrogen atmosphere the uptake of /sup 14/C-SA is partially inhibited above pH 5. Phosphate metabolism may be important for flowering since increasing the phosphate level in the medium 10-15 fold results in substantial flowering, and suboptimal levels of Sa and phosphate interact synergistically to stimulate flowering. The interaction of phosphate with BA and p-OH-BA will be presented.

Cleland, F.C.; Kang, B.G.; Khurana, J.P.

1986-04-01

61

Augmenting the activity of antifungal agents against aspergilli using structural analogues of benzoic acid as chemosensitizing agents.  

PubMed

A number of benzoic acid analogues showed antifungal activity against strains of Aspergillus flavus, Aspergillus fumigatus and Aspergillus terreus, causative agents of human aspergillosis, in in vitro bioassays. Structure-activity analysis revealed that antifungal activities of benzoic and gallic acids were increased by addition of a methyl, methoxyl or chloro group at position 4 of the aromatic ring, or by esterification of the carboxylic acid with an alkyl group, respectively. Thymol, a natural phenolic compound, was a potent chemosensitizing agent when co-applied with the antifungal azole drugs fluconazole and ketoconazole. The thymol-azole drug combination demonstrated complete inhibition of fungal growth at dosages far lower than the drugs alone. Co-application of thymol with amphotericin B had an additive effect on all strains of aspergilli tested with the exception of two of three strains of A. terreus, where there was an antagonistic effect. Use of two mitogen-activated protein kinase (MAPK) mutants of A. fumigatus, sakA? and mpkC?, having gene deletions in the oxidative stress response pathway, indicated antifungal and/or chemosensitization activity of the benzo analogues was by disruption of the oxidative stress response system. Results showed that both these genes play overlapping roles in the MAPK system in this fungus. The potential of safe, natural compounds or analogues to serve as chemosensitizing agents to enhance efficacy of commercial antifungal agents is discussed. PMID:20943191

Kim, Jong H; Campbell, Bruce C; Mahoney, Noreen; Chan, Kathleen L; Molyneux, Russell J; Balajee, Arunmozhi

2010-10-01

62

A quantitative relationship between structure and reactivity for the reactions between diphenyldiazomethanes and benzoic acids in toluene at 25° C  

E-print Network

, Y. Okamoto and H. C. Brown, J. Qrg. Chem., 22, ^85 (1957)* 21 C. Walling and E. A. McElhill, J. Am. Chem. Soc., 73 > d.dm? ? ? ? ? ? ? ? reaction of type (9)? i? e?> substituted benzoic acids versus substituted diphenyldiazomethanes... 3-Methylbenzoic 108-109 108.75a k-Methylbenzoic 179-180 179*6a 3-Nitrobenzoic l*f2* 5-1^3 l43a ?LI. M* Heilbron, "Dictionary of Organic Compounds,11 Oxford University Press, New York, N. Y., 1938. *bJ. B. Shoesmith and A. McKie, J. Chem. Soc...

Westmoreland, John Sherman

2013-10-04

63

Benzoic acid fermentation from starch and cellulose via a plant-like ?-oxidation pathway in Streptomyces maritimus  

PubMed Central

Background Benzoic acid is one of the most useful aromatic compounds. Despite its versatility and simple structure, benzoic acid production using microbes has not been reported previously. Streptomyces are aerobic, Gram-positive, mycelia-forming soil bacteria, and are known to produce various kinds of antibiotics composed of many aromatic residues. S. maritimus possess a complex amino acid modification pathway and can serve as a new platform microbe to produce aromatic building-block compounds. In this study, we carried out benzoate fermentation using S. maritimus. In order to enhance benzoate productivity using cellulose as the carbon source, we constructed endo-glucanase secreting S. maritimus. Results After 4?days of cultivation using glucose, cellobiose, or starch as a carbon source, the maximal level of benzoate reached 257, 337, and 460?mg/l, respectively. S. maritimus expressed ?-glucosidase and high amylase-retaining activity compared to those of S. lividans and S. coelicolor. In addition, for effective benzoate production from cellulosic materials, we constructed endo-glucanase-secreting S. maritimus. This transformant efficiently degraded the phosphoric acid swollen cellulose (PASC) and then produced 125?mg/l benzoate. Conclusions Wild-type S. maritimus produce benzoate via a plant-like ?-oxidation pathway and can assimilate various carbon sources for benzoate production. In order to encourage cellulose degradation and improve benzoate productivity from cellulose, we constructed endo-glucanase-secreting S. maritimus. Using this transformant, we also demonstrated the direct fermentation of benzoate from cellulose. To achieve further benzoate productivity, the L-phenylalanine availability needs to be improved in future. PMID:22545774

2012-01-01

64

Crystal structure of hydroxynitrile lyase from Sorghum bicolor in complex with the inhibitor benzoic acid: a novel cyanogenic enzyme.  

PubMed

The crystal structure of the hydroxynitrile lyase from Sorghum bicolor (SbHNL) in complex with the inhibitor benzoic acid has been determined at 2.3 A resolution and refined to a crystallographic R-factor of 16.5%. The SbHNL sequence places the enzyme in the alpha/beta hydrolase family where the active site nucleophile is predicted to be organized in a characteristic pentapeptide motif which is part of the active site strand-turn-helix motif. In SbHNL, however, a unique two-amino acid deletion is next to the putative active site Ser158, removing thereby the putative oxyanion hole-forming Tyr residue. The presented X-ray structure shows that the overall folding pattern of SbHNL is similar to that of the closely related wheat serine carboxypeptidase (CPD-WII); however, the deletion in SbHNL is forcing the putative active site residues away from the expected hydrolase binding site toward a small hydrophobic cleft, which also contains the inhibitor benzoic acid, defining thereby a completely different SbHNL active site architecture where the traditional view of a classic triad is not given any more. Rather, we propose a mechanism involving general base catalysis by the carboxy-terminal Trp270 carboxyl group and proton transfer toward the leaving nitrile group by an active site water molecule. The unexpected interactions of the inhibitor with the new SbHNL active site also reveal the structural basis for the enzyme's limited substrate specificity. The implications of this structure on the evolution of catalysis in the hydroxynitrile lyase superfamily are discussed. PMID:12356304

Lauble, Hanspeter; Miehlich, Burkhard; Förster, Siegfried; Wajant, Harald; Effenberger, Franz

2002-10-01

65

Influence of bleaching on flavor of 34% whey protein concentrate and residual benzoic acid concentration in dried whey proteins.  

PubMed

Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations in dried whey products. No legal limit exists in the United States for BP use in whey, but international concerns exist. The objectives of this study were to determine the effect of hydrogen peroxide (HP) or BP bleaching on the flavor of 34% WPC (WPC34) and to evaluate residual BA in commercial and experimental WPC bleached with and without BP. Cheddar whey was manufactured in duplicate. Pasteurized fat-separated whey was subjected to hot bleaching with either HP at 500 mg/kg, BP at 50 or 100 mg/kg, or no bleach. Whey was ultrafiltered and spray dried into WPC34. Color [L*(lightness), a* (red-green), and b* (yellow-blue)] measurements and norbixin extractions were conducted to compare bleaching efficacy. Descriptive sensory and instrumental volatile analyses were used to evaluate bleaching effects on flavor. Benzoic acid was extracted from experimental and commercial WPC34 and 80% WPC (WPC80) and quantified by HPLC. The b* value and norbixin concentration of BP-bleached WPC34 were lower than HP-bleached and control WPC34. Hydrogen peroxide-bleached WPC34 displayed higher cardboard flavor and had higher volatile lipid oxidation products than BP-bleached or control WPC34. Benzoyl peroxide-bleached WPC34 had higher BA concentrations than unbleached and HP-bleached WPC34 and BA concentrations were also higher in BP-bleached WPC80 compared with unbleached and HP-bleached WPC80, with smaller differences than those observed in WPC34. Benzoic acid extraction from permeate showed that WPC80 permeate contained more BA than did WPC34 permeate. Benzoyl peroxide is more effective in color removal of whey and results in fewer flavor side effects compared with HP and residual BA is decreased by ultrafiltration and diafiltration. PMID:21854907

Listiyani, M A D; Campbell, R E; Miracle, R E; Dean, L O; Drake, M A

2011-09-01

66

Tailoring band gaps of insulators by adsorption at surface defects: Benzoic acids on NaCl surfaces  

NASA Astrophysics Data System (ADS)

The adsorption of benzoic acid and its OH-substituted derivatives, namely, salicylic acid (SA) and parasalicylic acid on various NaCl surfaces has been investigated by density-functional theory with hybrid exchange-correlation functional. The ideal NaCl(100) surface is chemically inert as evidenced by the low binding energies. The molecular adsorption can be enhanced by both an anion vacancy and a surface step site. The bonding between the surface Na and the carboxylic O atom is of covalent character for all adsorption geometries. Our calculations show that the adsorption of SA has the largest binding energy of all three acids due to the additional interaction between Na and the phenolic O atom. Charge transfer between the molecule and the surface is generally very small, except in the presence of an anion vacancy where the unpaired electron is mostly transferred to the adsorbate. Surface defects generally have a strong influence on the electronic structure of the adsorbed molecules. Specifically, the adsorption of SA at [011]-oriented steps can significantly reduce the effective band gap to 1.6 eV due to the up shift of the Cl3p levels at the undercoordinated step edge. Implications of these results to the contact charging effect between wide-band-gap insulators will be discussed.

Chen, Wei; Tegenkamp, Christoph; Pfnür, Herbert; Bredow, Thomas

2009-06-01

67

Functional electrospun nanofibres of poly(lactic acid) blends with polyaniline or poly(aniline- co-benzoic acid)  

Microsoft Academic Search

Functionalised nanofibres of a controlled fibre diameter were electrospun from solutions of polyaniline (PANI) or poly(aniline-co-m-aminobenzoic acid) (P(ANI-co-m-ABA)) with poly(lactic acid) (PLA). Soluble copolymers of aniline (ANI) and m-aminobenzoic acid (m-ABA) were prepared and the average molecular weight of the copolymers, as determined by gel permeation chromatography, was found to decrease from 13,800gmol?1 to 1640gmol?1 with an increase of m-ABA

Norizah Abdul Rahman; Marija Gizdavic-Nikolaidis; Sudip Ray; Allan J. Easteal; Jadranka Travas-Sejdic

2010-01-01

68

Alteration of the phospho- or neutral lipid content and fatty acid composition in Listeria monocytogenes due to acid adaptation mechanisms for hydrochloric, acetic and lactic acids at pH 5.5 or benzoic acid at neutral pH  

PubMed Central

This study provides a first approach to observe the effects on Listeria monocytogenes of cellular exposure to acid stress at low or neutral pH, notably how phospho- or neutral lipids are involved in this mechanism, besides the fatty acid profile alteration. A thorough investigation of the composition of polar and neutral lipids from L. monocytogenes grown at pH 5.5 in presence of hydrochloric, acetic and lactic acids, or at neutral pH 7.3 in presence of benzoic acid, is described relative to cells grown in acid-free medium. The results showed that only low pH values enhance the antimicrobial activity of an acid. We suggest that, irrespective of pH, the acid adaptation response will lead to a similar alteration in fatty acid composition [decreasing the ratio of branched chain/saturated straight fatty acids of total lipids], mainly originating from the neutral lipid class of adapted cultures. Acid adaptation in L. monocytogenes was correlated with a decrease in total lipid phosphorus and, with the exception of cells adapted to benzoic acid, this change in the amount of phosphorus reflected a higher content of the neutral lipid class. Upon acetic or benzoic acid stress the lipid phosphorus proportion was analysed in the main phospholipids present: cardiolipin, phosphatidylglycerol, phosphoaminolipid and phosphatidylinositol. Interestingly only benzoic acid had a dramatic effect on the relative quantities of these four phospholipids. PMID:20379849

Berberi, Anita; Diakogiannis, Ioannis; Petrova, Evanthia; Kiaki, Irene; Baltzi, Triantafillia; Xenikakis, Polydoros

2010-01-01

69

2-Amino-benzoic acid-4-[2-(pyridin-4-yl)eth-yl]pyridine (2/1)  

PubMed Central

The asymmetric unit of the title co-crystal, C12H12N2·2C7H7NO2, comprises a centrosymmetric 4-[2-(pyridin-4-yl)eth­yl]pyridine mol­ecule and a 2-amino­benzoic acid mol­ecule in a general position. The acid has a small twist between the carb­oxy­lic acid residue and the ring [dihedral angle = 7.13?(6)°] despite the presence of an intra­molecular N—H?O(carbon­yl) hydrogen bond. Three-mol­ecule aggregates are formed via O—H?N(pyrid­yl) hydrogen bonds, and these are connected into supra­molecular layers in the bc plane by N—H?O(carbon­yl) hydrogen bonds and ?–? inter­actions between pyridine and benzene rings [inter-centroid distance = 3.6332?(9)?Å]. Layers are connected along the a axis by weak ?–? inter­actions between benzene rings [3.9577?(10)?Å]. PMID:24454067

Arman, Hadi D.; Tiekink, Edward R. T.

2013-01-01

70

Quantitative solubility-structure relationships for some meta- and para-substituted benzoic acids  

E-print Network

of the re- quirements;for the degree of MASTER OF SCIENCE Augus t 1963 Ma)or Sub)ect: Chemistry QUANTITATIVE SOLUBILITY-STRUCTURE RELATIONSHIPS POR SOME META- AND PARA-SUBSTITUTED BENZGIC ACIDS A Thesis JOHN NORMAN PAWLOSKI Approved as to style... Solubilities of the Substituted Bensoic kcids in Cyclohexane and in Bensene at 30oC 10 Iv+ Svapozation Test of Acids in Dry State at 2500 12 V. Runs to Det~ if the kcids Evaporate in Solution at 30 0 13 VI. Blank Runs to Deteraine if Soxhlet Filters...

Pawlowski, John Norman

2012-06-07

71

Free and Conjugated Benzoic Acid in Tobacco Plants and Cell Cultures. Induced Accumulation upon Elicitation of Defense Responses and Role as Salicylic Acid Precursors1  

PubMed Central

Salicylic acid (SA) is a key endogenous component of local and systemic disease resistance in plants. In this study, we investigated the role of benzoic acid (BA) as precursor of SA biosynthesis in tobacco (Nicotiana tabacum cv Samsun NN) plants undergoing a hypersensitive response following infection with tobacco mosaic virus or in tobacco cell suspensions elicited with ?-megaspermin, an elicitor from Phytophthora megasperma. We found a small pool of conjugated BA in healthy leaves and untreated cell suspensions of tobacco, whereas free BA levels were barely detectable. Infection of plants with tobacco mosaic virus or elicitation of cells led to a rapid de novo synthesis and accumulation of conjugated BA, whereas free BA was weakly induced. In presence of diphenylene iodonium, an inhibitor of superoxide anion formation, SA accumulation was abolished in elicited cells and much higher BA levels were concomitantly induced, mainly as a conjugated form. Furthermore, piperonylic acid, an inhibitor of cinnamate-4-hydroxylase was used as a powerful tool to redirect the metabolic flow from the main phenylpropanoid pathway into the SA biosynthetic branch. Under these conditions, in vivo labeling and radioisotope dilution experiments with [14C]trans-cinnamic acid as precursor clearly indicated that the free form of BA produced in elicited tobacco cells is not the major precursor of SA biosynthesis. The main conjugated form of BA accumulating after elicitation of tobacco cells was identified for the first time as benzoyl-glucose. Our data point to the likely role of conjugated forms of BA in SA biosynthesis. PMID:11154339

Chong, Julie; Pierrel, Marie-Agnes; Atanassova, Rossitza; Werck-Reichhart, Daniele; Fritig, Bernard; Saindrenan, Patrick

2001-01-01

72

Design of a turn-linker-turn foldamer by incorporating meta-amino benzoic acid in the middle of a helix forming hexapeptide sequence: A helix breaking approach  

NASA Astrophysics Data System (ADS)

Single crystal X-ray diffraction studies reveal that the incorporation of meta-amino benzoic acid in the middle of a helix forming hexapeptide sequence such as in peptide I Boc-Ile(1)-Aib(2)-Val(3)- m-ABA(4)-Ile(5)-Aib(6)-Leu(7)-OMe (Aib: ?-amino isobutyric acid; m-ABA: meta-amino benzoic acid) breaks the helix propagation to produce a turn-linker-turn (T-L-T) foldamer in the solid state. In the crystalline state two conformational isomers of peptide I self-assemble in antiparallel fashion through intermolecular hydrogen bonds and aromatic ?-? interactions to form a molecular duplex. The duplexes are further interconnected through intermolecular hydrogen bonds to form a layer of peptides. The layers are stacked one on top of the other through van der Waals interactions to form hydrophilic channels filled with solvent methanol.

Dutta, Arpita; Drew, Michael G. B.; Pramanik, Animesh

2009-07-01

73

Growth, thermal, dielectric and mechanical properties of L-phenylalanine-benzoic acid: a nonlinear optical single crystal.  

PubMed

An efficient amino acid family nonlinear optical single crystal L-phenylalanine-benzoic acid (LPB) was conveniently grown by slow evaporation technique at room temperature. The crystal system and the lattice parameters were analyzed by single crystal X-ray diffraction studies. The grown crystal has excellent transmission in the entire visible region and its lower cut-off wavelength was found to be 248 nm. The SHG efficiency of the grown crystal was found to be 1.6 times higher than that of KDP crystal. The Laser damage threshold value of LPB has been found to be 6.5 GW/cm(2). The sample was thermally stable up to 134°C. Microhardness, dielectric and AC/DC conductivity measurements were made along (001) plane and reported for the first time. Microhardness studies revealed that the sample belongs to hard nature. Frequency dependent dielectric constant was measured for different temperatures and found maximum dielectric constant of 14 for 363 K. Photoconductivity studies of LPB divulged its negative photoconducting nature. PMID:23747430

Tamilselvan, S; Vimalan, M; Potheher, I Vetha; Rajasekar, S; Jeyasekaran, R; Arockiaraj, M Antony; Madhavan, J

2013-10-01

74

Escherichia coli ATCC 8739 Adapts to the Presence of Sodium Chloride, Monosodium Glutamate, and Benzoic Acid after Extended Culture  

PubMed Central

Escherichia coli is commonly found in intestine of human, and any changes in their adaptation or evolution may affect the human body. The relationship between E. coli and food additives is less studied as compared to antibiotics. E. coli within our human gut are consistently interacting with the food additives; thus, it is important to investigate this relationship. In this paper, we observed the evolution of E. coli cultured in different concentration of food additives (sodium chloride, benzoic acid, and monosodium glutamate), singly or in combination, over 70 passages. Adaptability over time was estimated by generation time and cell density at stationary phase. Polymerase chain reaction (PCR)/restriction fragments length polymorphism (RFLP) using 3 primers and restriction endonucleases, each was used to characterize adaptation/evolution at genomic level. The amplification and digestion profiles were tabulated and analyzed by Nei-Li dissimilarity index. Our results demonstrate that E. coli in every treatment had adapted over 465 generations. The types of stress were discovered to be different even though different concentrations of same additives were used. However, RFLP shows a convergence of genetic distances, suggesting the presence of global stress response. In addition, monosodium glutamate may be a nutrient source and support acid resistance in E. coli. PMID:23724334

Lee, Chin How; Oon, Jack S. H.; Lee, Kun Cheng; Ling, Maurice H. T.

2012-01-01

75

Regulation of Lipid Synthesis in Soybeans by Two Benzoic Acid Herbicides 1  

PubMed Central

The effects of 3-nitro-2,5-dichlorobenzoic acid (dinoben) and 3-amino-2,4-dichlorobenzoic acid (chloramben) on lipid formation and on the incorporation of various substrates into lipids by intact seeds and subcellular fractions of germinating soybean (Glycine max [L.] Merr. `Amsoy') were studied. Dinoben (20 ?g/ml) inhibited synthesis of total lipids 67%, neutral lipids 73%, glycolipids 51%, and phospholipids 39% in germinating seeds. When polar lipids were analyzed further, inhibition of individual lipid classes was also observed. Chloramben (20 ?g/ml) stimulated total lipid synthesis 25%. With the exception of the mitochondrial fraction where malonate thiokinase was absent, dinoben inhibited up to 99% the incorporation of acetate and malonate into lipids, but did not inhibit acetyl-CoA and malonyl-CoA incorporation. Chloramben stimulated the incorporation of all substrates tested into lipids by all fractions except the mitochondrial fraction when malonate was the substrate. When dinoben and chloramben were used in combinations, chloramben did not reverse the inhibitory effect of dinoben. It is concluded that the dinoben inhibitory effect is specific and is associated with the acetate and malonate thiokinase systems. The chloramben effect is stimulatory to either acetyl-CoA carboxylase or fatty acid synthetase or both. PMID:16660173

Muslih, Raad K.; Linscott, Dean L.

1977-01-01

76

Degradation of chloro- and methyl-substituted benzoic acids by a genetically modified microorganism  

SciTech Connect

Degradation of 3-chlorobenzoic acid (3CB), 4-chlorobenzoic acid (4CB), and 4-methylbenzoic acid (4MB) as single substrates (carbon sources) and as a substrate mixture were studied in batch and continuous culture using the genetically modified microorganism Pseudomonas sp. B13 FR1 SN45P. The strain was able to mineralize the single compounds as well as the substrate mixture completely. Conversion of the three compounds in the substrate mixture proceeded simultaneously. Maximum specific substrate conversion rates were calculated to be 0.9 g g{sup {minus}1} h{sup {minus}1} for 3 CB and 4CB and 1.1 g g{sup {minus}1} h{sup {minus}1} for 4MB. Mass balances indicated the transient accumulation of pathway intermediates during batch cultivations. Hence, the rate limiting step in the degradative pathway is not the initial microbial attack of the original substrate or its transport through the cell membrane. Degradation rates on 3CB were comparable to those of the parent strain Pseudomonas sp. B13. The stability of the degradation pathways of strain Pseudomonas sp. B13 FR1 SN45P could be demonstrated in a continuous cultivation over 3.5 months (734 generation times) on 3CB, 4MB, and 4CB, which were used a single carbon sources one after the other.

Mueller, R.; Deckwer, W.D.; Hecht, V. [Gesellschaft fuer Biotechnologische Forschung mbH, Braunschweig (Germany)

1996-09-05

77

1H-Benzotriazole–4-hy­droxy­benzoic acid (1/1)  

PubMed Central

The asymmetric unit of the title compound, C6H5N3·C7H6O3, comprises independent benzotriazole and 4-hydroxybenzoic acid molecules. The dihedral angle between the benzene ring and the benzotriazole ring system is 15.18?(7)°. The mean plane of the carb­oxyl group is twisted at an angle of 18.55?(1)° with respect to the benzene ring. The crystal structure is stabilized by weak inter­molecular N—H?N, O—H?N, O—H?O and C—H?O inter­actions, forming a three-dimensional network. PMID:24454057

Thirunavukkarasu, A.; Silambarasan, A.; Chakkaravarthi, G.; Mohankumar, R.; Umarani, P. R.

2013-01-01

78

Crystal structure of complexes of bivalent Co, Ni, and Cd with anions of benzoic and 2-(acetylamino)-5-nitrobenzoic acids  

SciTech Connect

The structure of three complexes of bivalent metals (cobalt, nickel, and cadmium) with anions of benzoic (HL{sup 1}) and 2-(acetylamino)-5-nitrobenzoic (HL{sup 2}) acids, namely, [Co{sub 2}{sup 1} (H{sub 2}O){sub 2}({mu}-C{sub 4}H{sub 4}N{sub 2})]{sub n} (I), [NiL{sup 2}(H{sub 2}O){sub 5}]L{sup 2} {center_dot} 2H{sub 2}O (II), and [Cd({mu}-L{sup 2}){sub 2}(H{sub 2}O){sub 2}]{sub n} {center_dot} 2nH{sub 2}O (III), is determined. In chainlike structure I, cobalt atoms are connected by bridging pyrazine molecules; structure II contains isolated complexes. In structure III, centrosymmetric (CdOCO){sub 2} cycles and polymeric ribbons are formed due to the coordination of the carboxylate group of the L{sup 2} ligand to two cadmium atoms.

Rzaeva, M. F. [Azerbaijan State Agricultural University (Azerbaijan); Askerov, R. K. [Baku State University (Azerbaijan); Movsumov, E. M. [Azerbaijan State Agricultural University (Azerbaijan); Sergienko, V. S.; Ilyukhin, A. B. [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation)

2012-03-15

79

Influence of metal salts of 4-(2, 4, 6-trinitroanilino) benzoic acid on the burnining rate of double base propellants  

Microsoft Academic Search

Cobalt, Nickel, Copper and Lead salts of 4-(2, 4, 6-trinitroanilino) benzoic acid have been evaluated as ballistic modifiers in double base propellant formulations. Measurements showed considerable increase in burning rate over the control propellant, in presence of salts at all pressures in the range 3.43 – 8.82 MPa. The effect of the lead salt, however, was more pronounced and showed

S. M. Pundlik; R. S. Palaiah; J. K. Nair; T. Mukundan; S. N. Singh; Haridwar Singh

2001-01-01

80

Functionalization of chitosan with 3-nitro-4-amino benzoic acid moiety and its application to the collection\\/concentration of molybdenum in environmental water samples  

Microsoft Academic Search

A chitosan resin functionalized with 3-nitro-4-amino benzoic acid moiety (CCTS-NABA resin) was newly synthesized for the collection\\/concentration of trace molybdenum by using cross-linked chitosan (CCTS) as base material. The carboxyl group of the moiety was chemically attached to amino group of cross-linked chitosan through amide bond formation. The adsorption behavior of molybdenum as well as other 60 elements on the

Akhmad Sabarudin; Mitsuko Oshima; Osamu Noguchi; Shoji Motomizu

2007-01-01

81

Novel class of benzoic acid ester derivatives as potent PDE4 inhibitors for inhaled administration in the treatment of respiratory diseases.  

PubMed

The first steps in the selection process of a new anti-inflammatory drug for the inhaled treatment of asthma and chronic obstructive pulmonary disease are herein described. A series of novel ester derivatives of 1-(3-(cyclopropylmethoxy)-4-(difluoromethoxy)phenyl)-2-(3,5-dichloropyridin-4-yl) ethanol have been synthesized and evaluated for inhibitory activity toward cAMP-specific phosphodiesterase-4 (PDE4). In particular, esters of variously substituted benzoic acids were extensively explored, and structural modification of the alcoholic and benzoic moieties were performed to maximize the inhibitory potency. Several compounds with high activity in cell-free and cell-based assays were obtained. Through the evaluation of opportune in vitro ADME properties, a potential candidate suitable for inhaled administration in respiratory diseases was identified and tested in an in vivo model of pulmonary inflammation, proving its efficacy. PMID:24400806

Armani, Elisabetta; Amari, Gabriele; Rizzi, Andrea; De Fanti, Renato; Ghidini, Eleonora; Capaldi, Carmelida; Carzaniga, Laura; Caruso, Paola; Guala, Matilde; Peretto, Ilaria; La Porta, Elena; Bolzoni, Pier T; Facchinetti, Fabrizio; Carnini, Chiara; Moretto, Nadia; Patacchini, Riccardo; Bassani, Franco; Cenacchi, Valentina; Volta, Roberta; Amadei, Francesco; Capacchi, Silvia; Delcanale, Maurizio; Puccini, Paola; Catinella, Silvia; Civelli, Maurizio; Villetti, Gino

2014-02-13

82

Excited state intramolecular proton transfer and dual emission of the cyclic homo- and heterodimers of 2-hydroxy and 2,6-dihydroxy benzoic acids  

NASA Astrophysics Data System (ADS)

The fluorescence and excitation spectra of homo- and heterodimers formed by salicylic and 2,6-dihydroxy benzoic acids (SA and DHBA respectively) with various carboxylic acids were obtained in the crystalline state, liquid and frozen glassy solutions within the temperature range 300-90 K. In all the cases, dual emission has been found with the low frequency band attributed to the excited state with intramolecular proton transfer (ESIPT) and the high frequency one to a state without ESIPT. The relative intensities of these bands depend strongly on the temperature, excitation wavelength and the pK a value of the second acid molecule involved in a cyclic dimer. The dual emission of molecules like methyl salicylate is conventionally explained in terms of the ground state tautomeric equilibrium with the OH ⋯ OH intramolecularly hydrogen bonded isomer incapable of ESIPT. Since in the case of 2,6-dihydroxy benzoic acid the only stable isomer with two hydrogen bonds can exist, this explanation seems to be at least insufficient. Other explanations of the dual emission origin are discussed. An attempt is made to explain the available experimental data using the hypothesis involving double well potential surface of the cyclic dimer in the excited state. In the framework of this hypothesis, the barrier between two wells emerges from the reorganization of the whole hydrogen bonded system of a dimer.

Denisov, G. S.; Golubev, N. S.; Schreiber, V. M.; Shajakhmedov, Sh. S.; Shurukhina, A. V.

1996-07-01

83

Hexacoordinated cobalt(II) and nickel(II) complexes of a novel mixed ligand, N-(2-methylpyridine)-2-aminomethyl benzoic acid: structures, spectroscopic characterizations and redox studies  

Microsoft Academic Search

Two new metal complexes, [Co(Mamba)2] and [Ni(Mamba)2], have been prepared by the treatment of the tridentate ligand N-(2-methylpyridine)-2-aminomethyl benzoic acid (HMamba) with the respective metal salts (Co(ClO4)2 and Ni(C2H3O2)2) in the presence of sodium hydroxide. The ligand was synthesized by reduction of the Schiff base which was obtained by condensation of 2-carboxybenzaldehyde with 2-(aminomethyl)pyridine. The complexes have been characterized using

Xiaobao Li; Ghezai T Musie; Douglas R Powell

2003-01-01

84

Comparison of the antitumor activity of DTIC and 1- p -(3,3-dimethyl-1-triazeno) benzoic acid potassium salt on murine transplantable tumors and their hematological toxicity  

Microsoft Academic Search

This study describes a comparison of 1-p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK) and imidazole-4-carboxamide,5-(3,3-dimethyl-1-triazeno) (DTIC) with reference to antitumor activity on different murine tumors and hematological toxicity. DM-COOK appeared comparably or slightly more effective in L1210, P388, and M5 tumors in the mouse. However, when the treatment of mice bearing M5 with DM-COOK was combined with surgical removal of the primary

Tina Colombo; Maurizio D'Incalci

1984-01-01

85

Cellular and Subcellular Localization of S-Adenosyl-l-Methionine:Benzoic Acid Carboxyl Methyltransferase, the Enzyme Responsible for Biosynthesis of the Volatile Ester Methylbenzoate in Snapdragon Flowers1  

PubMed Central

The benzenoid ester, methylbenzoate is one of the most abundant scent compounds detected in the majority of snapdragon (Antirrhinum majus) varieties. It is produced in upper and lower lobes of petals by enzymatic methylation of benzoic acid in the reaction catalyzed by S-adenosyl-l-methionine:benzoic acid carboxyl methyltransferase (BAMT). To identify the location of methylbenzoate biosynthesis, we conducted an extensive immunolocalization study by light and electron microscopy at cellular and subcellular levels using antibodies against BAMT protein. BAMT was immunolocalized predominantly in the conical cells of the inner epidermal layer and, to a much lesser extent, in the cells of the outer epidermis of snapdragon flower petal lobes. It was also located in the inner epidermis of the corolla tube with little BAMT protein detected in the outer epidermis and in the yellow hairs within the tube on the bee's way to the nectar. These results strongly suggest that scent biosynthetic genes are expressed almost exclusively in the epidermal cells of floral organs. Immunogold labeling studies reveal that BAMT is a cytosolic enzyme, suggesting cytosolic location of methylbenzoate biosynthesis. The concentration of scent production on flower surfaces that face the pollinators during landing may increase pollination efficiency and also help to minimize the biosynthetic cost of advertising for pollinators. PMID:11457946

Kolosova, Natalia; Sherman, Debra; Karlson, Dale; Dudareva, Natalia

2001-01-01

86

D77, one benzoic acid derivative, functions as a novel anti-HIV-1 inhibitor targeting the interaction between integrase and cellular LEDGF/p75  

SciTech Connect

Integration of viral-DNA into host chromosome mediated by the viral protein HIV-1 integrase (IN) is an essential step in the HIV-1 life cycle. In this process, Lens epithelium-derived growth factor (LEDGF/p75) is discovered to function as a cellular co-factor for integration. Since LEDGF/p75 plays an important role in HIV integration, disruption of the LEDGF/p75 interaction with IN has provided a special interest for anti-HIV agent discovery. In this work, we reported that a benzoic acid derivative, 4-[(5-bromo-4-{l_brace}[2,4-dioxo-3-(2-oxo-2-phenylethyl) -1,3-thiazolidin-5-ylidene]methyl{r_brace}-2-ethoxyphenoxy)methyl]benzoic acid (D77) could potently inhibit the IN-LEDGF/p75 interaction and affect the HIV-1 IN nuclear distribution thus exhibiting antiretroviral activity. Molecular docking with site-directed mutagenesis analysis and surface plasmon resonance (SPR) binding assays has clarified possible binding mode of D77 against HIV-1 integrase. As the firstly discovered small molecular compound targeting HIV-1 integrase interaction with LEDGF/p75, D77 might supply useful structural information for further anti-HIV agent discovery.

Du Li [Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203 (China); Zhao Yaxue [School of Pharmacy, East China University of Science and Technology, Shanghai 200237 (China); Chen, Jing [Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203 (China); Yang Liumeng; Zheng Yongtang [Laboratory of Molecular Immunopharmacology, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223 (China); Tang Yun [School of Pharmacy, East China University of Science and Technology, Shanghai 200237 (China)], E-mail: ytang234@ecust.edu.cn; Shen Xu [Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203 (China); School of Pharmacy, East China University of Science and Technology, Shanghai 200237 (China)], E-mail: xshen@mail.shcnc.ac.cn; Jiang Hualiang [Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203 (China); School of Pharmacy, East China University of Science and Technology, Shanghai 200237 (China)

2008-10-10

87

[Rh(III)(Cp*)]-catalyzed ortho-selective direct C(sp(2))-H bond amidation/amination of benzoic acids by N-chlorocarbamates and N-chloromorpholines. A versatile synthesis of functionalized anthranilic acids.  

PubMed

A Rh(III) -catalyzed direct ortho-C?H amidation/amination of benzoic acids with N-chlorocarbamates/N-chloromorpholines was achieved, giving anthranilic acids in up to 85?% yields with excellent ortho-selectivity and functional-group tolerance. Successful benzoic acid aminations were achieved with carbamates bearing various amide groups including NHCO2 Me, NHCbz, and NHTroc (Cbz=carbobenzyloxy; Troc=trichloroethylchloroformate), as well as secondary amines, such as morpholines, piperizines, and piperidines, furnishing highly functionalized anthranilic acids. A stoichiometric reaction of a cyclometallated rhodium(III) complex of benzo[h]quinoline with a silver salt of N-chlorocarbamate afforded an amido-rhodium(III) complex, which was isolated and structurally characterized by X-ray crystallography. This finding confirmed that the C?N bond formation results from the cross-coupling of N-chlorocarbamate with the aryl-rhodium(III) complex. Yet, the mechanistic details regarding the C?N bond formation remain unclear; pathways involving 1,2-aryl migration and rhodium(V)- nitrene are plausible. PMID:24596116

Ng, Fo-Ning; Zhou, Zhongyuan; Yu, Wing-Yiu

2014-04-01

88

Synthesis of a New Thermal and Photostable Reference Probe for Qf Measurement in Aqua: Water Soluble N,N'-bis-(2Hydroxy4-benzoic Acid)-3,4,9,10-perylenebis(dicarboximide)  

Microsoft Academic Search

N,N?-bis(2-hydroxy-4-benzoic acid)-3,4,9,10-perylenebis(dicarboximide) is synthesized from perylene 3,4,9,10-tetracarboxylic dianhydride and 4-amino-3-hydroxy benzoic acid in 90% yield. Together with the photostability the dye is also very stable thermally. The fluorescence quantum yield is measured as one, Qf=1.The diimide dissolves in water at PH = 8 completely. The diimide is an ideal reference probe for fluorescence quantum yield measurements in 500–650 nm region

Huriye Icil; Duygu Uzun; Nur Pasaogullari

1998-01-01

89

Inhibition of soluble epoxide hydrolase by trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB) is protective against ischemia reperfusion injury  

PubMed Central

Arachidonic acid, a polyunsaturated fatty acid, can be metabolized to cardioprotective epoxyeicosatrienoic acids (EETs) by cytochrome P450 epoxygenases, which are subsequently hydrolyzed to less bioactive dihydroxyeicosatrienoic acids by soluble epoxide hydrolase (sEH). To study the effects of pharmacological inhibitor of sEH (sEHi), C57BL6 mice hearts were perfused in Langendorff mode for 40min of baseline and subjected to 30min of global no-flow ischemia followed by 40 min of reperfusion. Hearts were perfused with the sEHi, trans-4-[4-(3-adamantan-1-y1-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB; 0.05 µM, 0.1 µM, 0.5 µM and 1 µM). To study the mechanism(s), hearts were perfused with 0.1 µM t-AUCB in the presence or absence of putative EET receptor antagonist 14,15-epoxyeicosa-5(Z)-enoic acid (14,15-EEZE, 10 µM) or phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin (200 nM) or LY294002 (5 µM). Infarct size was determined at the end of 2 h reperfusion by TTC staining. Inhibition of sEH by t-AUCB significantly improved postischemic left ventricular developed pressure (LVDP) recovery and reduced the infarct size following ischemia-reperfusion, as compared to control hearts. Perfusion with 14,15-EEZE, wortmannin or LY294002 prior to ischemia abolished the cardioprotective phenotype; however, co-perfusion of both t-AUCB and 11,12-EET did not result in an additive effect on improved LVDP recovery. Together, our data suggest that pharmacological inhibition of sEH by t-AUCB is cardioprotective. PMID:19834332

Chaudhary, Ketul R.; Abukhashim, Mohamed; Hwang, Sung Hee; Hammock, Bruce D.; Seubert, John M.

2009-01-01

90

Copolymers and their polychelates derived from hydroxy benzoic ( o - and p -) acids as antifungal and antibacterial agents  

Microsoft Academic Search

A series of complexes of salicylic acid-thiourea-trioxane polymer andp-hydroxybenzoic acid-thiourea-trioxane polymer respectively were isolated and characterised by elemental analysis and infrared\\u000a data. The antimicrobial activity of these complexes against various bacteria and fungi is studied, which indicates that in\\u000a several cases, the complexes possess fairly highly anti-microbial activity. A probable mechanism for the toxic action of these\\u000a complexes against various

M. M. Patel; R. Manavalan; K. Prabhakaran

1983-01-01

91

Adjuvant effects and antiserum action potentiation by a (herbal) compound 2-hydroxy-4-methoxy benzoic acid isolated from the root extract of the Indian medicinal plant `sarsaparilla' ( Hemidesmus indicus R. Br.)  

Microsoft Academic Search

The adjuvant effect and antiserum potentiation of a compound 2-hydroxy-4-methoxy benzoic acid were explored in the present investigation. This compound, isolated and purified from the Indian medicinal plant Hemidesmus indicus R. Br, possessed antisnake venom activity. Rabbits immunized with Vipera russellii venom in the presence and absence of the compound along with Freund's complete adjuvant, produced a precipitating band in

M. I. Alam; A. Gomes

1998-01-01

92

Development and validation of an HPLC-DAD method for simultaneous determination of cocaine, benzoic acid, benzoylecgonine and the main adulterants found in products based on cocaine.  

PubMed

Here, an HPLC-DAD method was developed and validated for simultaneous determination of cocaine, two cocaine degradation products (benzoylecgonine and benzoic acid), and the main adulterants found in products based on cocaine (caffeine, lidocaine, phenacetin, benzocaine and diltiazem). The new method was developed and validated using an XBridge C18 4.6mm×250mm, 5?m particle size column maintained at 60°C. The mobile phase consisted of a gradient of acetonitrile and ammonium formate 0.05M - pH 3.1, eluted at 1.0mL/min. The volume of injection was 10?L and the DAD detector was set at 274nm. Method validation assays demonstrated suitable sensitivity, selectivity, linearity, precision and accuracy. For selectivity assay, a MS detection system could be directly adapted to the method without the need of any change in the chromatographic conditions. The robustness study indicated that the flow rate, temperature and pH of the mobile phase are critical parameters and should not be changed considering the conditions herein determined. The new method was then successfully applied for determining cocaine, benzoylecgonine, benzoic acid, caffeine, lidocaine, phenacetin, benzocaine and diltiazem in 115 samples, seized in Brazil (2007-2012), which consisted of cocaine paste, cocaine base and salt cocaine samples. This study revealed cocaine contents that ranged from undetectable to 97.2%, with 97 samples presenting at least one of the degradation products or adulterants here evaluated. All of the studied degradation products and adulterants were observed among the seized samples, justifying the application of the method, which can be used as a screening and quantification tool in forensic analysis. PMID:24447449

Floriani, Gisele; Gasparetto, João Cleverson; Pontarolo, Roberto; Gonçalves, Alan Guilherme

2014-02-01

93

4,4?-{[1,2-Phenyl-enebis(methyl-ene)]bis-(-oxy)}di-benzoic acid di-methyl-formamide disolvate  

PubMed Central

In the title solvate, C22H18O6·2C3H7NO, the complete dicarboxylic acid molecule is generated by a crystallographic twofold axis, which bisects the central benzene ring and one N,N-di­methyl­formamide solvent mol­ecule. The dihedral angle between the central and pendant benzene rings is 54.53?(5)° while that between the pendant rings is 45.44?(5)°. In the crystal, the acid molecules are linked to the solvent molecules via O—H?O and weak C—H?O hydrogen bonds. Further weak C—H?O inter­actions link adjacent acid mol­ecules into a three-dimensional network. PMID:24860345

Qiu, Zhen-Zhe; Jing, Bi; Li, Qiu-Xia; Zhu, Ai-Xin

2014-01-01

94

Adsorption of benzoic acid on pure and cupric ion-modified hydroxyapatite: implications for design of a coupling agent to dental polymer composites.  

PubMed

The adsorption isotherms of benzoic acid on synthetic hydroxyapatite (containing about 1.5 monolayers of physisorbed water) were studied from ethanol, dimethylsulfoxide, p-dioxane, methylene chloride, and benzene to discern the role of solvent in the process. The adsorption is reversible from the first three solvents and follows the Langmuir plots. It is irreversible from the last two, and a constant amount of absorbent is removed from solutions above a certain concentration. The isotherms of potassium benzoate on the apatite from ethanol and dimethyl sulfoxide were reversible. The isotherms of the acid on cupric ion-modified apatite surfaces from ethanol and benzene were identical with those obtained on the pure hydroxyapatite. This may demonstrate that any "surface chelation" with the cation may not be a significant factor for adsorption to occur. The adsorptive behavior seems to depend upon the interplay of hydrogen-bonding among the solute, the solvent, and the hydrated apatite surface. The capability of a solvent to hydrogen-bond may determine whether adsorption from it will be reversible or irreversible. Based upon its compatibility with a solvent, the benzene ring is upright or lies flat on the surface. The adsorbed molecules rotate about the center of the carboxylate groups which are hydrogen-bonded to the surface. These factors should be considered in designing or selecting a suitable surface-active moiety for a coupling agent between tooth mineral and a restorative resin. PMID:3009580

Misra, D N

1986-05-01

95

Crystal structure of di-?-benzato-?4 O:O?-bis-[aqua-(benzato-?O)(benzato-?2 O,O?)(2,2?:6?,2??-terpyridine-?3 N,N?,N??)europium(III)]-benzoic acid (1/2)  

PubMed Central

The title compound, [Eu2(C7H5O2)6(C15H11N3)2(H2O)2]·2C7H6O2, is a co-crystalline compound containing a dinuclear EuIII coordination complex with inversion symmetry co-crystallized with benzoic acid in a 1:2 ratio. The Eu3+ ions within the dimer are nine-coordinate, containing one tridentate terpyridine, one water, and four benzoate ions, two of which bridge the Eu3+ ions. Of the four benzoate ligands coordinating to each Eu3+ position, three distinct coordination modes [monodentate, bidentate–chelating, and bidentate–bridging (twice)] are observed. Within the crystal, there are two additional uncoordinating benzoic acid mol­ecules per dinuclear complex. Within the dimer, the water bound to each Eu3+ ion participates in intra­molecular hydrogen bonding with a coordinating benzoate. Additionally, the carb­oxy­lic acid group on the benzoic acid participates in inter­molecular hydrogen bonding with a benzoate ligand bound to the dimer complex.

White, Frankie; Sykora, Richard E.

2014-01-01

96

Biosynthesis of biphenyls and benzophenones--evolution of benzoic acid-specific type III polyketide synthases in plants.  

PubMed

Type III polyketide synthases (PKSs) generate a diverse array of secondary metabolites by varying the starter substrate, the number of condensation reactions, and the mechanism of ring closure. Among the starter substrates used, benzoyl-CoA is a rare starter molecule. Biphenyl synthase (BIS) and benzophenone synthase (BPS) catalyze the formation of identical linear tetraketide intermediates from benzoyl-CoA and three molecules of malonyl-CoA but use alternative intramolecular cyclization reactions to form 3,5-dihydroxybiphenyl and 2,4,6-trihydroxybenzophenone, respectively. In a phylogenetic tree, BIS and BPS group together closely, indicating that they arise from a relatively recent functional diversification of a common ancestral gene. The functionally diverse PKSs, which include BIS and BPS, and the ubiquitously distributed chalcone synthases (CHSs) form separate clusters, which originate from a gene duplication event prior to the speciation of the angiosperms. BIS is the key enzyme of biphenyl metabolism. Biphenyls and the related dibenzofurans are the phytoalexins of the Maloideae. This subfamily of the Rosaceae includes a number of economically important fruit trees, such as apple and pear. When incubated with ortho-hydroxybenzoyl (salicoyl)-CoA, BIS catalyzes a single decarboxylative condensation with malonyl-CoA to form 4-hydroxycoumarin. A well-known anticoagulant derivative of this enzymatic product is dicoumarol. Elicitor-treated cell cultures of Sorbus aucuparia also formed 4-hydroxycoumarin when fed with the N-acetylcysteamine thioester of salicylic acid (salicoyl-NAC). BPS is the key enzyme of benzophenone metabolism. Polyprenylated benzophenone derivatives with bridged polycyclic skeletons are widely distributed in the Clusiaceae (Guttiferae). Xanthones are regioselectively cyclized benzophenone derivatives. BPS was converted into a functional phenylpyrone synthase (PPS) by a single amino acid substitution in the initiation/elongation cavity. The functional behavior of this Thr135Leu mutant was rationalized by homology modeling. The intermediate triketide may be redirected into a smaller pocket in the active site cavity, resulting in phenylpyrone formation by lactonization. PMID:19699497

Beerhues, Ludger; Liu, Benye

2009-01-01

97

Simultaneous determination of triflusal and its major active metabolite, 2-hydroxy-4-trifluoromethyl benzoic acid, in rat and human plasma by high-performance liquid chromatography.  

PubMed

A rapid, selective and sensitive high-performance liquid chromatography (HPLC) method was developed and validated for the simultaneous determination of triflusal and its major active metabolite, 2-hydroxy-4-trifluoromethyl benzoic acid (HTB), in rat and human plasma. HPLC analysis was carried out using a 5-microm particle size, C18-bonded silica column and acetonitrile-methanol-water (25:10:65, v/v/v) as the mobile phase and UV detection at 234 nm. Furosemide was used as the internal standard. The method involved extraction with an acetonitrile-chloroform mixture (60:40, v/v) and evaporation to dryness with nitrogen stream. The chromatograms showed good resolution and sensitivity and no interferences by plasma constituents. The mean absolute recovery for human plasma was 93.5 +/- 4.2% for triflusal and 98.5 +/- 3.1% for HTB. The lower limits of quantification of triflusal and HTB in human plasma were 20 and 100 ng/ml, respectively. The calibration curves in human plasma were linear over the concentration range 0.02-5.0 microg/ml for triflusal and 0.1-200.0 microg/ml for HTB with correlation coefficients greater than 0.999 and with inter- or intra-day coefficients of variation (CV) not exceeding 10.0%. This assay procedure was applied to the study of metabolite pharmacokinetics of triflusal and HTB in rat and human. PMID:14643505

Cho, Hea-Young; Jeong, Tae-Jin; Lee, Yong-Bok

2003-12-25

98

Modulation of Cyclins, p53 and Mitogen-Activated Protein Kinases Signaling in Breast Cancer Cell Lines by 4-(3,4,5-Trimethoxyphenoxy)benzoic Acid  

PubMed Central

Despite the advances in cancer therapy and early detection, breast cancer remains a leading cause of cancer-related deaths among females worldwide. The aim of the current study was to investigate the antitumor activity of a novel compound, 4-(3,4,5-trimethoxyphenoxy)benzoic acid (TMPBA) and its mechanism of action, in breast cancer. Results indicated the relatively high sensitivity of human breast cancer cell-7 and MDA-468 cells towards TMPBA with IC50 values of 5.9 and 7.9 ?M, respectively compared to hepatocarcinoma cell line Huh-7, hepatocarcinoma cell line HepG2, and cervical cancer cell line Hela cells. Mechanistically, TMPBA induced apoptotic cell death in MCF-7 cells as indicated by 4?,6-diamidino-2-phenylindole (DAPI) nuclear staining, cell cycle analysis and the activation of caspase-3. Western blot analysis revealed the ability of TMPBA to target pathways mediated by mitogen-activated protein (MAP) kinases, 5? adenosine monophosphate-activated protein kinase (AMPK), and p53, of which the concerted action underlined its antitumor efficacy. In addition, TMPBA induced alteration of cyclin proteins’ expression and consequently modulated the cell cycle. Taken together, the current study underscores evidence that TMPBA induces apoptosis in breast cancer cells via the modulation of cyclins and p53 expression as well as the modulation of AMPK and mitogen-activated protein kinases (MAPK) signaling. These findings support TMPBA’s clinical promise as a potential candidate for breast cancer therapy. PMID:24406729

Lee, Kuan-Han; Ho, Wen-Yueh; Wu, Shu-Jing; Omar, Hany A.; Huang, Po-Jui; Wang, Clay C. C.; Hung, Jui-Hsiang

2014-01-01

99

Fischer indolisation of N-(?-ketoacyl)anthranilic acids into 2-(indol-2-carboxamido)benzoic acids and 2-indolyl-3,1-benzoxazin-4-ones and their NMR study.  

PubMed

N-(?-ketoacyl)anthranilic acids reacted with phenylhydrazinium chloride in boiling acetic acid to afford 2-(indol-2-carboxamido)benzoic acids in good to excellent yields and 2-indolyl-3,1-benzoxazin-4-ones as by-products. The formation of the latter products could easily be suppressed by a hydrolytic workup. Alternatively, by increasing the reaction temperature and/or time, 2-indolyl-3,1-benzoxazin-4-ones can be obtained exclusively. Optimisations of the reaction conditions as well as the scope and the course of the transformations were investigated. The products were characterized by (1)H, (13)C and (15)N NMR spectroscopy. The corresponding resonances were assigned on the basis of the standard 1D and gradient selected 2D NMR experiments ((1)H-(1)H gs-COSY, (1)H-(13)C gs-HSQC, (1)H-(13)C gs-HMBC) with (1)H-(15)N gs-HMBC as a practical tool to determine (15)N NMR chemical shifts at the natural abundance level of (15)N isotope. PMID:25347568

Proisl, Karel; Kafka, Stanislav; Urankar, Damijana; Gazvoda, Martin; Kimmel, Roman; Košmrlj, Janez

2014-12-21

100

Synthesis and application of a new chelating resin functionalized with 2,3-dihydroxy benzoic acid for Fe(III) determination in water samples by flame atomic absorption spectrometry  

Microsoft Academic Search

To obtain a selective chelating resin for separation and preconcentration of Fe(III) ions in various water samples, amberlite XAD-4 was functionalized with 2,3-dihydroxy benzoic acid by coupling it through an –NN– spacer. The resulting resin, characterized by thermogravimetric analysis and infrared (IR) spectroscopy, was packed in a minicolumn to be used as a sorbent. It was shown that Fe3+ ions

Mohammad Saeid Hosseini; Haidar Raissi; Sara Madarshahian

2006-01-01

101

Soluble epoxide hydrolase inhibitor trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid is neuroprotective in rat model of ischemic stroke.  

PubMed

Soluble epoxide hydrolase (sEH) diminishes vasodilatory and neuroprotective effects of epoxyeicosatrienoic acids by hydrolyzing them to inactive dihydroxy metabolites. The primary goals of this study were to investigate the effects of acute sEH inhibition by trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB) on infarct volume, functional outcome, and changes in cerebral blood flow (CBF) in a rat model of ischemic stroke. Focal cerebral ischemia was induced in rats for 90 min followed by reperfusion. At the end of 24 h after reperfusion rats were euthanized for infarct volume assessment by triphenyltetrazolium chloride staining. Brain cortical sEH activity was assessed by ultra performance liquid chromatography-tandem mass spectrometry. Functional outcome at 24 and 48 h after reperfusion was evaluated by arm flexion and sticky-tape tests. Changes in CBF were assessed by arterial spin-labeled-MRI at baseline, during ischemia, and at 180 min after reperfusion. Neuroprotective effects of t-AUCB were evaluated in primary rat neuronal cultures by Cytotox-Flour kit and propidium iodide staining. t-AUCB significantly reduced cortical infarct volume by 35% (14.5 ± 2.7% vs. 41.5 ± 4.5%), elevated cumulative epoxyeicosatrienoic acids-to-dihydroxyeicosatrienoic acids ratio in brain cortex by twofold (4.40 ± 1.89 vs. 1.97 ± 0.85), and improved functional outcome in arm-flexion test (day 1: 3.28 ± 0.5 s vs. 7.50 ± 0.9 s; day 2: 1.71 ± 0.4 s vs. 5.28 ± 0.5 s) when compared with that of the vehicle-treated group. t-AUCB significantly reduced neuronal cell death in a dose-dependent manner (vehicle: 70.9 ± 7.1% vs. t-AUCB0.1?M: 58 ± 5.11% vs. t-AUCB0.5?M: 39.9 ± 5.8%). These findings suggest that t-AUCB may exert its neuroprotective effects by affecting multiple components of neurovascular unit including neurons, astrocytes, and microvascular flow. PMID:24043255

Shaik, Jafar Sadik B; Ahmad, Muzamil; Li, Wenjin; Rose, Marie E; Foley, Lesley M; Hitchens, T Kevin; Graham, Steven H; Hwang, Sung Hee; Hammock, Bruce D; Poloyac, Samuel M

2013-12-01

102

Mn (III) tetrakis (4-benzoic acid) porphyrin administered into the intrathecal space reduces oxidative damage and neuron death after spinal cord injury: a comparison with methylprednisolone.  

PubMed

The metalloporphyrin Mn (III) tetrakis (4-benzoic acid) porphyrin (MnTBAP) is a cell-permeable superoxide dismutase mimetic and a broad-spectrum scavenger of reactive species. Since MnTBAP may not cross the blood-brain barrier, this study evaluated the therapeutic potential of MnTBAP to treat spinal cord injury (SCI; 25 g x cm) by directly administering it into the intrathecal space of the rat spinal cord. The cells in spinal sections removed at 24 h post-SCI were immunohistochemically stained with anti-4-hydroxynonenal (HNE), a marker of membrane lipid peroxidation (MLP); anti-nitrotyrosine (Ntyr), a marker of protein nitration; and anti-neuron-specific enolase (NSE) antibodies. Immunostained neurons were counted for quantitative evaluation. Pre-treatment 30 min before SCI with 1 mg/kg MnTBAP or 4-h post-SCI treatment with 2.5 mg/kg MnTBAP administered into the intrathecal space significantly reduced MLP and protein nitration, and increased the number of surviving neurons compared to vehicle controls. However, post-SCI treatment with a standard regimen of methylprednisolone sodium succinate (MPSS; 30 mg/kg followed by 5.4 mg/kg for maintenance, iv administration), the only drug used for clinical treatment of SCI, not only did not reduce MLP and neuron loss, it increased protein nitration compared with vehicle controls (two-way analysis of variance [ANOVA] followed by the Tukey test). These results demonstrate that pre- and post-intrathecal treatments with the low doses of MnTBAP provide sustained neuroprotection by preventing oxidative stress and that post-treatment with MnTBAP is superior to post-treatment with MPSS in preventing oxidative stress and resulting neuron loss. PMID:17184187

Hachmeister, Jorge E; Valluru, Lokanatha; Bao, Feng; Liu, Danxia

2006-12-01

103

Mn (III) tetrakis (4-benzoic acid) porphyrin scavenges reactive species, reduces oxidative stress, and improves functional recovery after experimental spinal cord injury in rats: comparison with methylprednisolone  

PubMed Central

Background Substantial experimental evidence supports that reactive species mediate secondary damage after traumatic spinal cord injury (SCI) by inducing oxidative stress. Removal of reactive species may reduce secondary damage following SCI. This study explored the effectiveness of a catalytic antioxidant - Mn (III) tetrakis (4-benzoic acid) porphyrin (MnTBAP) - in removing reactive oxygen species (ROS), reducing oxidative stress, and improving functional recovery in vivo in a rat impact SCI model. The efficiency of MnTBAP was also compared with that of methylprednisolone – the only drug used clinically in treating acute SCI. Results In vivo measurements of time courses of ROS production by microdialysis and microcannula sampling in MnTBAP, methylprednisolone, and saline (as vehicle control)-treated SCI rats showed that both agents significantly reduced the production of hydrogen peroxide, but only MnTBAP significantly reduced superoxide elevation after SCI. In vitro experiments further demonstrated that MnTBAP scavenged both of the preceding ROS, whereas methylprednisolone had no effect on either. By counting the immuno-positive neurons in the spinal cord sections immunohistochemically stained with anti-nitrotyrosine and anti-4-hydroxy-nonenal antibodies as the markers of protein nitration and membrane lipid peroxidation, we demonstrated that MnTBAP significantly reduced the numbers of 4-hydroxy-nonenal-positive and nitrotyrosine-positive neurons in the sections at 1.55 to 2.55 mm and 1.1 to 3.1 mm, respectively, rostral to the injury epicenter compared to the vehicle-treated animals. By behavioral tests (open field and inclined plane tests), we demonstrated that at 4 hours post-SCI treatment with MnTBAP and the standard methylprednisolone regimen both significantly increased test scores compared to those produced by vehicle treatment. However, the outcomes for MnTBAP-treated rats were significantly better than those for methylprednisolone-treated animals. Conclusions This study demonstrated for the first time in vivo and in vitro that MnTBAP significantly reduced the levels of SCI-elevated ROS and that MnTBAP is superior to methylprednisolone in removing ROS. Removal of ROS by MnTBAP significantly reduced protein nitration and membrane lipid peroxidation in neurons. MnTBAP more effectively reduced neurological deficits than did methylprednisolone after SCI - the first most important criterion for assessing SCI treatments. These results support the therapeutic potential of MnTBAP in treating SCI. PMID:23452429

2013-01-01

104

Electron localization-delocalization matrices in the prediction of pKa's and UV-wavelengths of maximum absorbance of p-benzoic acids and the definition of super-atoms in molecules  

NASA Astrophysics Data System (ADS)

An integration of chemical graph theory and the quantum theory of atoms in molecules (QTAIM) is proposed. QTAIM localization and delocalization indices organized as matrices are shown useful in the modeling of ground and excited state molecular properties. The pKa's of 14 para-substituted benzoic acids and the ?max's of a subset of those are predicted with accuracy (pKa: r2 = 0.986, q2 = 0.982; ?max: r2 = 0.973, q2 = 0.944). ‘Super-atoms' obtained by pruning the branches of the substituents' graphs equalize the matrices of all molecules of the set. The pKa of p-dimethylaminobenzoic acid is found to be 5.02 rather than the reported value of 6.03.

Sumar, Ismat; Ayers, Paul W.; Matta, Chérif F.

2014-09-01

105

Structural diversity and magnetic properties of six metal-organic polymers based on semirigid tricarboxylate ligand of 3,5-bi(4-carboxyphenoxy)benzoic acid.  

PubMed

Solvothermal reactions of the semirigid 3,5-bi(4-carboxyphenoxy)benzoic acid (H3BCP) and transitional metal cations with the help of three ancillary bridging imidazole linkers afforded six coordination polymers, namely, [Co(HBCP)(1,4-bib)0.5]n (), {[Mn1.5(BCP)(1,4-bib)0.5(?2-H2O)(H2O)2]·(1,4-bib)0.5}n (), {[Mn0.5(1,4-bib)(H2O)]·(H2BCP)}n (), {[Fe(BCP)0.5(HCOO)0.5(4,4'-bibp)0.5]·2H2O}n (), [Ni2.5(HBCP)(BCP)(4,4'-bibp)2(?2-H2O)(H2O)2]n (), and [Ni(HBCP)(1,4-bidb)1.5(H2O)2]n (), (1,4-bib = 1,4-bis(1H-imidazol-4-yl)benzene, 1,4-bidb = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene, 4,4'-bibp = 4,4'-bis(imidazol-1-yl)biphenyl). Their structures and properties were determined by single-crystal and powder X-ray diffraction analyses, IR spectra, elemental analyses, thermogravimetric analyses (TGA), and X-ray photoelectron spectroscopy (XPS). Complex displays unusual 2D + 2D?2D parallel entangled networks consisting of (3,4)-connected 3,4L83 sheets. Complex exhibits an interesting 2-fold interpenetrated framework with a trinodal (4,4,6)-connected (3·4·5·6(2)·7)2(3·6·7(4))2(3(2)·4(2)·5(2)·6(2)·7(6)·9) topology. The host network of complex is a 2D 4-connected (4(4)·6(2))-sql sheet. Complex affords unprecedented 3D (4,6,6)-coordinated framework with point symbol of (4(5)·6)(4(8)·6(7))(4(9)·6(3)·8(3))2, in which the 1D helix water chains occupy the void channels. Complex can be regarded as a novel self-penetrating (4,4,4,5)-coordinated framework with point symbol of (4·5(4)·6)2(4·6(5)·7·8(3))2(5·6·7·8(3))2(5(2)·8(3)·9(2)), which contains two interpenetrated (3,4,4,5)-coordinated (4·5(4)·6)2(4·6(5)·7·8(3))2(5·6·7)2(5(2)·8(3)·9(2)) subnets linked by ?2-H2O. Complex shows a 1D ladder chain, which are further assembled into a 3D supramolecular structure via O-HO and ?? interactions. Moreover, magnetic studies indicate that both complex and show antiferromagnetic properties. PMID:25233393

Fan, Liming; Fan, Weiliu; Song, Weikuo; Sun, Liming; Zhao, Xian; Zhang, Xiutang

2014-10-01

106

Reactions of 2-mercaptobenzoic acid with divalent alkaline earth metal ions: synthesis, spectral studies, and single-crystal X-ray structures of calcium, strontium, and barium complexes of 2,2'-dithiobis(benzoic acid).  

PubMed

The treatment of MCl(2).nH(2)O (M = Ca, Sr, or Ba) with 2-mercaptobenzoic acid (H-2-MBA) in a 1:2 ratio in an EtOH/H(2)O/NH(3) mixture leads to the formation of extended polymeric solids [[Ca(OOCC(6)H(4)SSC(6)H(4)COO)(H(2)O)(2)].0.5(C(2)H(5)OH)](n)(1), [[Sr(OOCC(6)H(4)SSC(6)H(4)COO)(H(2)O)(2)].0.5(C(2)H(5)OH)](n)(2), and [[Ba(2)(OOCC(6)H(4)SSC(6)H(4)COO)(2)(H(2)O)(2)].0.5H(2)O](n)(3), respectively. In all of the cases, under the reaction conditions employed, the H-2-MBA ligand undergoes thiol oxidation to form 2,2'-dithiobis(benzoic acid) (H(2)-DTBB). While the DTBB forms a 1:1 complex with heavier alkaline earth metals (1-3), only an ammonium salt, [(HOOCC(6)H(4)SSC(6)H(4)COOH)(HOOCC(6)H(4)SSC(6)H(4)COONH(4))] (4), was obtained as the final product in the reaction of H-2-MBA with MgCl(2).6H(2)O. Compounds 1-4 have been characterized with the aid of elemental analysis, thermal analysis, and infrared spectroscopic studies. All of the products are found to be thermally stable and do not melt on heating to 250 degrees C. Thermogravimetry on complexes 1-3 indicates the loss of coordinated and lattice water/solvent molecules below 200 degrees C (for complex 2) or 350 degrees C (for complexes 1 and 3). The solid-state structures of all of the derivatives 1-4 have been established by single-crystal X-ray diffraction studies. The calcium and strontium coordination polymers 1 and 2 are isomorphous. The DTBB ligands in 1 and 2 are hexadentate, and the compounds have a channel structure in which solvent ethanol molecules are included. In compound 3, barium ion forms a complex 3-dimensional coordination polymer where both the carboxylate and the sulfur centers of the DTBB ligands (which are hepta- and octadentate) coordinate to the metal. PMID:11754266

Murugavel, R; Baheti, K; Anantharaman, G

2001-12-31

107

DFT calculations, spectroscopic, thermal analysis and biological activity of Sm(III) and Tb(III) complexes with 2-aminobenzoic and 2-amino-5-chloro-benzoic acids  

NASA Astrophysics Data System (ADS)

The complexes of Sm(III) and Tb(III) with 2-aminobenzoic acid (anthranilic acid, AA) and 2-amino-5-chlorobenzoic acid (5-chloroanthranilic acid, AACl) were synthesized and characterized based on elemental analysis, IR and mass spectroscopy. The data are in accordance with 1:3 [Metal]:[Ligand] ratio. On the basis of the IR analysis, it was found that the metals were coordinated to bidentate anthranilic acid via the ionised oxygen of the carboxylate group and to the nitrogen of amino group. While in 5-chloroanthranilic acid, the metals were coordinated oxidatively to the bidentate carboxylate group without bonding to amino group; accordingly, a chlorine-affected coordination and reactivity-diversity was emphasized. Thermal analyses (TGA) and biological activity of the complexes were also investigated. Density Functional Theory (DFT) calculations at the B3LYP/6-311++G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligand. The optimized geometry parameters of the complexes were evaluated using SDDALL basis set. Moreover, total energy, energy of HOMO and LUMO and Mullikan atomic charges were calculated. In addition, dipole moment and orientation have been performed and discussed.

Essawy, Amr A.; Afifi, Manal A.; Moustafa, H.; El-Medani, S. M.

2014-10-01

108

Inhibition of soluble epoxide hydrolase by cis-4-[4-(3-adamantan-1-yl-ureido)cyclohexyl-oxy]benzoic acid exhibits antihypertensive and cardioprotective actions in transgenic rats with angiotensin II-dependent hypertension  

PubMed Central

The present study was undertaken to evaluate the effects of chronic treatment with cis-4-[4-(3- adamantan-1-yl-ureido)cyclohexyl-oxy]benzoic acid (c-AUCB), a novel inhibitor of soluble epoxide hydrolase (sEH), which is responsible for the conversion of biologically active epoxyeicosatrienoic acids (EETs) to biologically inactive dihydroxyeicosatrienoic acids (DHETEs), on blood pressure (BP) and myocardial infarct size in male heterozygous Ren-2 transgenic rats (TGR) with established hypertension. Normotensive Hannover Sprague-Dawley (HanSD) rats served as controls. Myocardial ischemia was induced by coronary artery occlusion. Systolic BP was measured in conscious animals by tail-plethysmography. c-AUCB was administrated in drinking water. Renal and myocardial concentrations of EETs and DHETEs served as markers of internal production of epoxygenase metabolites. Chronic treatment with c-AUCB, which resulted in significant increases in the availability of biologically active epoxygenase metabolites in TGR – assessed as the ratio of EETs/DHETEs – was accompanied by a significant reduction in BP and significantly reduced infarct size in TGR as compared with untreated TGR. The cardioprotective action of c-AUCB treatment was completely prevented by acute administration of a selective EETs antagonist (14,15-epoxyeicosa5(Z)-enoic acid), supporting the notion that the improved cardiac ischemic tolerance conferred by sEH inhibition is mediated by EETs actions at the cellular level. These findings indicate that chronic inhibition of sEH exhibits antihypertensive and cardioprotective actions in this transgenic model of angiotensin II-dependent hypertension. PMID:22324471

Neckár?, Jan; Kopkan, Libor; Husková, Zuzana; Kolár?, Frantis?ek; Papous?ek, Frantis?ek; Kramer, Herbert J.; Hwang, Sung Hee; Hammock, Bruce D.; Imig, John D.; Malý, Jir?í; Netuka, Ivan; Os?t’ádal, Bohuslav; C?ervenka, Lud?k

2012-01-01

109

Modeling, Synthesis and Biological Evaluation of Potential Retinoid-X-Receptor (RXR) Selective Agonists: Novel Halogenated Analogs of 4-[1-(3,5,5,8,8-Pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic Acid (Bexarotene)  

PubMed Central

The synthesis of halogenated analogs of 4-[1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (1), known commonly as bexarotene, and their evaluation for retinoid-X-receptor (RXR)-specific agonist performance is described. Compound 1 is FDA approved to treat cutaneous T-cell lymphoma (CTCL); however, bexarotene treatment can induce hypothyroidism and elevated triglyceride levels, presumably by disrupting RXR heterodimer pathways for other nuclear receptors. The novel halogenated analogs in this study were modeled and assessed for their ability to bind to RXR and stimulate RXR homodimerization in an RXRE-mediated transcriptional assay as well as an RXR mammalian-2-hybrid assay. In an array of 8 novel compounds, 4 analogs were discovered to promote RXR-mediated transcription with comparable EC50 values as 1 and are selective RXR agonists. Our approach also uncovered a periodic trend of increased binding and homodimerization of RXR when substituting a halogen atom for a proton ortho to the carboxylic acid on 1. PMID:22927238

Furmick, Julie K.; Kaneko, Ichiro; Walsh, Angela N.; Yang, Joanna; Bhogal, Jaskaran S.; Gray, Geoffrey M.; Baso, Juan C.; Browder, Drew O.; Prentice, Jessica L.S.; Montano, Luis A.; Huynh, Chanh C.; Marcus, Lisa M.; Tsosie, Dorian G.; Kwon, Jungeun S.; Quezada, Alexis; Reyes, Nicole M.; Lemming, Brittney; Saini, Puneet; van der Vaart, Arjan; Groy, Thomas L.; Marshall, Pamela A.; Jurutka, Peter W.; Wagner, Carl E.

2012-01-01

110

Organotin(IV) Complexes of 2-[(2?,4?,6?- Trichlorophenylamido)]benzoic Acid: Synthesis, Coordination Chemistry, and SemiEmpirical Study  

Microsoft Academic Search

A new series of organotin(IV) complexes of aniline derivatives, R2SnL2 and R3SnL [where R = Me, n-Bu, n-Oct, and Ph], have been synthesized by the reaction of ligand acid with respective organotin halides in the presence of triethylamine as base or dioctyltin oxide using a Dean–Stark trap for the removal of water under reflux conditions. Experimental details for the preparation

Saira Shahzadi; Saqib Ali; Khadija Shahid; Saroj K. Sharma; Kushal Qanungo

2010-01-01

111

A Novel Electrochemical Sensor for Probing Doxepin Created on a Glassy Carbon Electrode Modified with Poly(4-Amino- benzoic Acid)/Multi-Walled Carbon Nanotubes Composite Film  

PubMed Central

A novel electrochemical sensor for sensitive detection of doxepin was prepared, which was based on a glassy carbon electrode modified with poly(4-aminobenzoic acid)/multi-walled carbon nanotubes composite film [poly(4-ABA)/MWNTs/GCE]. The sensor was characterized by scanning electron microscopy and electrochemical methods. It was observed that poly(4-ABA)/MWNTs/GCE showed excellent preconcentration function and electrocatalytic activities towards doxepin. Under the selected conditions, the anodic peak current was linear to the logarithm of doxepin concentration in the range from 1.0 × 10?9 to 1.0 × 10?6 M, and the detection limit obtained was 1.0 × 10?10 M. The poly(4-ABA)/MWNTs/GCE was successfully applied in the measurement of doxepin in commercial pharmaceutical formulations, and the analytical accuracy was confirmed by comparison with a conventional ultraviolet spectrophotometry assay. PMID:22163661

Xu, Xiao-Li; Huang, Fei; Zhou, Guo-Liang; Zhang, Song; Kong, Ji-Lie

2010-01-01

112

Five new Zn(II) and Cd(II) coordination polymers constructed by 3,5-bis-oxyacetate-benzoic acid: Syntheses, crystal structures, network topologies and luminescent properties  

NASA Astrophysics Data System (ADS)

Five Zn(II) and Cd(II) coordination polymers, [Zn2(BOABA)(bpp)(OH)]·0.5H2O (1), [Cd3(BOABA)2(bpp)2(H2O)6]·2H2O (2), [Cd3(BOABA)2(2,2'-bipy)3(H2O)4]·5.5H2O (3), [CdNa(BOABA)(H2O)]2·H2O (4) and [Cd2(BOABA)(bimb)Cl(H2O)2]·H2O (5) (H3BOABA=3,5-bis-oxyacetate-benzoic acid, bpp=1,3-bi(4-pyridyl)propane, 2,2'-bipy=2,2'-bipyridine, bimb=1,4-bis(imidazol-1'-yl)butane), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and TG analyses. 1 is an uninodal 4-connected 2D square grid network based on binuclear zinc clusters. 2 is 2D wavelike layer structure and further linked by hydrogen bonds into the final 3D (5,6,6)-connected topology network. 3 is 3-connected 2D topology network and the 2,2'-bipy ligands decorate in two different types. 4 is a (4,8)-connected 2D topology network with heterocaryotic {Cd2Na2} clusters and BOABA3- ligands. 5 can be rationalized as a (3,10)-connected 3D topology network with tetranuclear {Cd4Cl2} clusters and BOABA3- ligands. Meanwhile, photoluminescence studies revealed that these five coordination polymers display strong fluorescent emission bands in the solid state at room temperature.

Jiang, Xian-Rong; Yuan, Hong-Yan; Feng, Yun-Long

2012-07-01

113

A validated HPLC-ESI-MS/MS method for quantification of 2-hydroxy-4-methoxy benzoic acid from rat plasma and its application to pharmacokinetic study using sparse sampling methodology.  

PubMed

The phenolic compound, 2-hydroxy-4-methoxy benzoic acid (HMBA), is one of the major phytoconstituents of Decalepis arayalpathra (Joseph & Chandra.) Venter, a rare and endemic medicinal plant found in the Western Ghats of India. HMBA has been attributed to possess several biological effects including anti-inflammatory, anti-pyretic, anti-oxidant and anti-diabetic. The present article describes a rapid and sensitive liquid chromatography-tandem mass spectrometric method (HPLC-MS/MS) for the determination of HMBA in rat plasma. In brief, the developed assay involves pre-treatment of the plasma samples by an optimized solid phase extraction method (recoveries for HMBA greater than 90%) followed by chromatographic separation on a Cosmosil C18 (150mm×4.6mm i.d.; 5?m particle size) analytical column with mobile phase of methanol and 10mM ammonium formate (95:5 v/v; 0.2% formic acid) delivered at a constant flow rate of 1.0mL/min. The detection and quantification was performed using an Applied Biosystems Hybrid Q-Trap API 2000 mass spectrometer equipped with electrospray ionization source (ESI) functioning in negative mode. The developed assay was validated as per the US FDA bioanalytical guidelines with the calibration curve linear over the concentration range of 5.05-2019.60ng/mL (r(2)?0.9936) for HMBA from rat plasma. Further, the validated HPLC-MS/MS method was successfully applied to pharmacokinetic study of HMBA after oral administration of D. arayalpathra tuber extracts to female albino Wistar rats using sparse sampling methodology. Following oral administration, the maximum mean concentration in rat plasma (Cmax -1301.57±128.22ng/mL) was achieved at 1.5h (Tmax) and the area under the curve (AUC0-48h) was 8985.02±229.54ngh/mL. The elimination half-life (t1/2) and terminal elimination rate constant (Kel) were 2.48h and 0.28 L/h, respectively. PMID:25168218

Nair, Sreenath Nandakumar; Mhatre, Mandar; Menon, Sasikumar; Shailajan, Sunita

2014-11-01

114

Solid-phase extraction of acidic herbicides.  

PubMed

A discussion of solid-phase extraction method development for acidic herbicides is presented that reviews sample matrix modification, extraction sorbent selection, derivatization procedures for gas chromatographic analysis, and clean-up procedures for high-performance liquid chromatographic analysis. Acidic herbicides are families of compounds that include derivatives of phenol (dinoseb, dinoterb and pentachlorophenol), benzoic acid (acifluorfen, chloramben, dicamba, 3,5-dichlorobenzoic acid and dacthal--a dibenzoic acid derivative), acetic acid [2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)], propanoic acid [dichlorprop, fluazifop, haloxyfop, 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP) and silvex], butanoic acid [4-(2,4-dichlorophenoxy)butanoic acid (2,4-DB) and 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB)], and other miscellaneous acids such as pyridinecarboxylic acid (picloram) and thiadiazine dioxide (bentazon). PMID:10941675

Wells, M J; Yu, L Z

2000-07-14

115

Modeling, Synthesis and Biological Evaluation of Potential Retinoid-X-Receptor (RXR) Selective Agonists: Novel Analogs of 4-[1-(3,5,5,8,8-Pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic Acid (Bexarotene) and (E)-3-(3-(1,2,3,4-tetrahydro-1,1,4,4,6-pentamethylnaphthalen-7-yl)-4-hydroxyphenyl)acrylic acid (CD3254)  

PubMed Central

Three unreported analogs of 4-[1-(3,5,5,8,8-pentamethyl-5-6-7-8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (1), otherwise known as bexarotene, as well as four novel analogs of (E)-3-(3-(1,2,3,4-tetrahydro-1,1,4,4,6-pentamethylnaphthalen-7-yl)-4-hydroxyphenyl)acrylic acid (CD3254) are described, and evaluated for their retinoid-X-receptor (RXR)-selective agonism. Compound 1 has FDA approval as a treatment for cutaneous T-cell lymphoma (CTCL); though, treatment with 1 can elicit side-effects by disrupting other RXR-heterodimer receptor pathways. Of the 7 modeled novel compounds, all analogs stimulate RXR-regulated transcription in mammalian-2-hybrid and RXRE-mediated assays, possess comparable or elevated biological activity based on EC50 profiles, and retain similar or improved apoptotic activity in CTCL assays compared to 1. All novel compounds demonstrate selectivity for RXR and minimal crossover onto the retinoic-acid-receptor (RAR) compared to all-trans-retinoic acid, with select analogs also reducing inhibition of other RXR-dependent pathways (e.g., VDR-RXR). Our results demonstrate that further improvements in biological potency and selectivity of bexarotene can be achieved through rational drug design. PMID:24180745

Jurutka, Peter W.; Kaneko, Ichiro; Yang, Joanna; Bhogal, Jaskaran S.; Swierski, Johnathon C.; Tabacaru, Christa R.; Montano, Luis A.; Huynh, Chanh C.; Jama, Rabia A.; Mahelona, Ryan D.; Sarnowski, Joseph T.; Marcus, Lisa M.; Quezada, Alexis; Lemming, Brittney; Tedesco, Maria A.; Fischer, Audra J.; Mohamed, Said A.; Ziller, Joseph W.; Ma, Ning; Gray, Geoffrey M.; van der Vaart, Arjan; Marshall, Pamela A.; Wagner, Carl E.

2014-01-01

116

Acid rain  

Microsoft Academic Search

Acid precipitation is a global problem. The effects were first seen in Europe; it affects the Great Lakes and the Midwest because higher-than-normal levels of acidity in rain are found in these areas. Several bays of the Great Lakes are now known to receive substantial runoff from freshwater streams that have been made acidic by acid rains. These areas may

1979-01-01

117

Testing of organic acids in engine coolants  

SciTech Connect

The effectiveness of 30 organic acids as inhibitors in engine coolants is reported. Tests include glassware corrosion of coupled and uncoupled metals. FORD galvanostatic and cyclic polarization electrochemistry for aluminum pitting, and reserve alkalinity (RA) measurements. Details of each test are discussed as well as some general conclusions. For example, benzoic acid inhibits coupled metals well but is ineffective on cast iron when uncoupled. In benzoic acid inhibits coupled metals well but is ineffective on cast iron when uncoupled. In general, the organic acids provide little RA when titrated to a pH of 5.5, titration to a pH of 4.5 can result in precipitation of the acid. Trends with respect to acid chain length are reported also.

Weir, T.W. [ARCO Chemical Co., Newtown Square, PA (United States)

1999-08-01

118

Rosmarinic acid  

Microsoft Academic Search

Rosmarinic acid is an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid. It is commonly found in species of the Boraginaceae and the subfamily Nepetoideae of the Lamiaceae. However, it is also found in species of other higher plant families and in some fern and hornwort species. Rosmarinic acid has a number of interesting biological activities, e.g. antiviral, antibacterial, antiinflammatory and

Maike Petersen; Monique S. J Simmonds

2003-01-01

119

Shikimic Acid  

NSDL National Science Digital Library

The molecule for this month comes from the article Isolation of Shikimic Acid from Star Aniseed by Richard Payne and Michael Edmonds. Shikimic acid plays a key role in the biosynthesis of many important natural products including aromatic amino acids, alkaloids, phenolics, and phenylpropanoids. It plays such an important role that one of the key biosynthetic pathways is referred to as the shikimate pathway.

120

Acid rain  

Microsoft Academic Search

For the past five years, scientists at the Univ. of Colorado have been measuring acid precipitation in a subalpine watershed of the Colorado Rockies. Their measurements of snow and rain and creek water show a strong trend of increasing acidity that is traceable to the chemical reactions of burning fossil fuels. Possible effects of acid precipitation on the watershed's aquatic

Caile

2009-01-01

121

Effective Friedel-Crafts acylation of biotin acid chloride in trifluoromethanesulfonic acid.  

PubMed

Biotin is one of the most useful tags in (bio)analytical science due to its specific interaction with avidin, but is not easy to convert because of its low solubility in most solvents. Friedel-Crafts acylation of biotin acid chloride in triflic acid was examined, and the synthesized derivatives had stronger affinity to avidin than biotin in a binding assay using 2-(4'-hydroxyphenylazo)benzoic acid. PMID:23132579

Muto, Yasuyuki; Murai, Yuta; Sakihama, Yasuko; Hashidoko, Yasuyuki; Hashimoto, Makoto

2012-01-01

122

Rosmarinic acid.  

PubMed

Rosmarinic acid is an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid. It is commonly found in species of the Boraginaceae and the subfamily Nepetoideae of the Lamiaceae. However, it is also found in species of other higher plant families and in some fern and hornwort species. Rosmarinic acid has a number of interesting biological activities, e.g. antiviral, antibacterial, antiinflammatory and antioxidant. The presence of rosmarinic acid in medicinal plants, herbs and spices has beneficial and health promoting effects. In plants, rosmarinic acid is supposed to act as a preformed constitutively accumulated defence compound. The biosynthesis of rosmarinic acid starts with the amino acids L-phenylalanine and L-tyrosine. All eight enzymes involved in the biosynthesis are known and characterised and cDNAs of several of the involved genes have been isolated. Plant cell cultures, e.g. from Coleus blumei or Salvia officinalis, accumulate rosmarinic acid in amounts much higher than in the plant itself (up to 36% of the cell dry weight). For this reason a biotechnological production of rosmarinic acid with plant cell cultures has been proposed. PMID:12482446

Petersen, Maike; Simmonds, Monique S J

2003-01-01

123

Crystal structure of [propane-1,3-diylbis(piperidine-4,1-di-yl)]bis-[(pyridin-4-yl)methanone]-4,4'-oxydi-benzoic acid (1/1).  

PubMed

In the title co-crystal, C25H32N4O2·C14H10O5, mol-ecules are connected into supra-molecular chains aligned along [102] by O-H?N hydrogen bonding. These aggregate into supra-molecular layers oriented parallel to (20-1) by C-H?O inter-actions. These layers then stack in an ABAB pattern along the c crystal direction to give the full three-dimensional crystal structure. The central chain in the dipyridylamide has an anti-anti conformation. The dihedral angle between the aromatic ring planes is 29.96?(3)°. Disorder is noted in some of the residues in the structure and this is manifested in two coplanar dispositions of one statistically disordered carb-oxy-lic acid group. PMID:25309203

Low, Emily M; LaDuca, Robert L

2014-09-01

124

Crystal structure of [propane-1,3-diylbis(piperidine-4,1-di-yl)]bis-[(pyridin-4-yl)methanone]-4,4?-oxydi-benzoic acid (1/1)  

PubMed Central

In the title co-crystal, C25H32N4O2·C14H10O5, mol­ecules are connected into supra­molecular chains aligned along [102] by O—H?N hydrogen bonding. These aggregate into supra­molecular layers oriented parallel to (20-1) by C—H?O inter­actions. These layers then stack in an ABAB pattern along the c crystal direction to give the full three-dimensional crystal structure. The central chain in the dipyridylamide has an anti–anti conformation. The dihedral angle between the aromatic ring planes is 29.96?(3)°. Disorder is noted in some of the residues in the structure and this is manifested in two coplanar dispositions of one statistically disordered carb­oxy­lic acid group.

Low, Emily M.; LaDuca, Robert L.

2014-01-01

125

Elucidation of the biochemical basis for a clinical drug-drug interaction between atorvastatin and 5-(N-(4-((4-ethylbenzyl)thio)phenyl)sulfamoyl)-2-methyl benzoic acid (CP-778875), a subtype selective agonist of the peroxisome proliferator-activated receptor alpha.  

PubMed

1. 5-(N-(4-((4-ethylbenzyl)thio)phenyl)sulfamoyl)-2-methyl benzoic acid (CP-778875), an agonist of the peroxisome proliferator-activated receptor alpha, has been evaluated in the clinic to treat dyslipidemia and type 2 diabetes mellitus. Herein, we investigate the effect of CP-778875 on the pharmacokinetics of atorvastatin acid and its metabolites in humans. 2. The study incorporated a fixed-sequence design conducted in two groups. Group A was designed to estimate the effects of multiple doses of CP-778875 on the single dose pharmacokinetics of atorvastatin. Subjects in group A (n = 26) received atorvastatin (40 mg) on days 1 and 9 and CP-778875 (1.0 mg QD) on days 5-12. Group B was designed to examine the effects of multiple doses of atorvastatin on the single dose pharmacokinetics of CP-778875. Subjects in group B (n = 29) received CP-778875 (0.3 mg) on days 1 and 9 and atorvastatin (40 mg QD) on days 5-12. 3. Mean maximum serum concentration (Cmax) and area under the curve of atorvastatin were increased by 45% and 20%, respectively, upon co-administration with CP-778875. Statistically significant increases in the systemic exposure of ortho- and para-hydroxyatorvastatin were also observed upon concomitant dosing with CP-778875. CP-778875 pharmacokinetics, however, were not impacted upon concomitant dosing with atorvastatin. 4.? Inhibition of organic anion transporting polypeptide 1B1 by CP-778875 (IC50 = 2.14 ± 0.40 ?M) could be the dominant cause of the pharmacokinetic interaction as CP-778875 did not exhibit significant inhibition of cytochrome P450 3A4/3A5, multidrug resistant protein 1 or breast cancer resistant protein, which are also involved in the hepatobiliary disposition of atorvastatin. PMID:23631744

Kalgutkar, Amit S; Chen, Danny; Varma, Manthena V; Feng, Bo; Terra, Steven G; Scialis, Renato J; Rotter, Charles J; Frederick, Kosea S; West, Mark A; Goosen, Theunis C; Gosset, James R; Walsky, Robert L; Francone, Omar L

2013-11-01

126

Identification of Lactic Acid Bacteria from Chili Bo, a Malaysian Food Ingredient  

Microsoft Academic Search

Ninety-two strains of lactic acid bacteria (LAB) were isolated from a Malaysian food ingredient, chili bo, stored for up to 25 days at 28°C with no benzoic acid (product A) or with 7,000 mg of benzoic acid kg21 (product B). The strains were divided into eight groups by traditional phenotypic tests. A total of 43 strains were selected for comparison

JØRGEN J. LEISNER; BRUNO POT; HENRIK CHRISTENSEN; GULAM RUSUL; JOHN E. OLSEN; BEE WAH WEE; KHARIDAH MUHAMAD; HASANAH M. GHAZALI

1999-01-01

127

Acid rain  

SciTech Connect

This book presents the proceedings of the third annual conference sponsored by the Acid Rain Information Clearinghouse (ARIC). Topics covered include: Legal aspects of the source-receptor relationship: an energy perspective; Scientific uncertainty, agency inaction, and the courts; and Acid rain: the emerging legal framework.

White, J.C. (Cornell University, Ithaca, NY (US))

1988-01-01

128

Tranexamic Acid  

MedlinePLUS

Tranexamic acid comes as a tablet to take by mouth. It is usually taken with or without food three times a day for up to 5 days during monthly menstruation. You should begin taking this medication each month when your period starts. Do not take tranexamic acid when you do not have a period. Take ...

129

Acid rain  

Microsoft Academic Search

The causes and effects of acid rain are detailed. Sulfur dioxide and nitrogen dioxide emissions from anthropogenic sources are the primary causative agents. These emissions are transported over long distances and transformed into sulfates and nitrates and washed out of the atmosphere. Trends in acidity in precipitation water are reviewed for eastern portions of Canada and the U.S. Adverse effects

R. E. Ghelardi; B. L. Murphy

2009-01-01

130

Acid Rain  

Microsoft Academic Search

Measurements of the acidity of rain and snow reveal that in parts of the eastern U.S. and of western Europe precipitation has changed from a nearly neutral solution 200 years ago to a dilute solution of sulfuric and nitric acids today. The trend is a result of the emission of sulfur and nitrogen oxides to the atmosphere accompanying the rise

Gene E. Likens; Richard F. Wright; James N. Galloway; Thomas J. Butler

1979-01-01

131

Acid test  

NSDL National Science Digital Library

Baking soda can be used as an indicator of how much acid a substance contains. Lemons and limes have more acid in them than grapefruits and oranges. Indophenol can be used as an indicator of how much vitamin C is in a substance.

Olivia Worland (Purdue University;Biological Sciences)

2008-06-06

132

Domoic Acid  

NSDL National Science Digital Library

This online student report discusses the chemistry of domoic acid, a biotoxin that is produced by the diatom Psuedo-nitzschia and associated with Amnesiac Shellfish Poisoning (ASP). In addition to a descriptive summary and images, the report links to other areas of interest related to domoic acid poisoning including signs and symptoms, modes of action, and treatment.

Bailey, Christina; Kohlen, Corinne

2010-02-10

133

Asparagusic acid.  

PubMed

Asparagusic acid (1,2-dithiolane-4-carboxylic acid) is a simple sulphur-containing 5-membered heterocyclic compound that appears unique to asparagus, though other dithiolane derivatives have been identified in non-food species. This molecule, apparently innocuous toxicologically to man, is the most probable culprit responsible for the curious excretion of odorous urine following asparagus ingestion. The presence of the two adjacent sulphur atoms leads to an enhanced chemical reactivity, endowing it with biological properties including the ability to substitute potentially for ?-lipoic acid in ?-keto-acid oxidation systems. This brief review collects the scattered data available in the literature concerning asparagusic acid and highlights its properties, intermediary metabolism and exploratory applications. PMID:24099657

Mitchell, Stephen C; Waring, Rosemary H

2014-01-01

134

Isolation of benzoic and cinnamic acid derivatives from the grains of Sorghum bicolor and their inhibition of lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells.  

PubMed

Two new caffeoylglycerols, (hwanggeumchal A-B, 9-10), together with eight known derivatives (1-8) were isolated from the grains of Sorghum bicolor (L.) Moench var. hwanggeumchal. Their chemical structures were established mainly by 1D and 2D NMR techniques and MS data analysis. Amongst those, methyl 3,4-dihydroxybenzoate (2), 3,4,5-trihydroxycinnamate (3), methyl 3,4-dihydroxycinnamate (5), caffeoylglycolic acid methyl ester (7) and 1-O-caffeoylglycerol (8) displayed potential inhibitory effects against LPS-induced NO production in macrophage RAW264.7 cells with IC50 values of 11.9, 2.9, 27.1, 29.0 and 18.5?M, respectively. Furthermore, these compounds dose-dependently reduced the LPS-induced iNOS expression. In addition, pre-incubation of cells with compounds 2, 3 and 5 significantly suppressed LPS-induced COX-2 protein expression. SAR investigation revealed that compounds with a methyl ester (COOCH3) group possessed stronger activity. Our obtained data suggest that S. bicolor and its caffeoylglyceride-enrich extracts may be applied as supplemental and/or functional foods having a beneficial effect against inflammation. PMID:25172742

Nguyen, Phi-Hung; Zhao, Bing Tian; Lee, Jeong Hyung; Kim, Young Ho; Min, Byung Sun; Woo, Mi Hee

2015-02-01

135

Acid Rain  

NSDL National Science Digital Library

Due to the presence of dissolved gases such as carbon dioxide, rainfall is naturally acidic. The release of other gases and chemicals such as sulfur dioxide during the combustion of coal and oil can cause rainfall to become even more acidic, sometimes to the point of toxicity. In this activity, students will measure the pH of local rainfall to see what effect these gases have in their region. They will also check an online resource to see how the releases of acid rain-causing chemicals have varied over the past 20 years, and answer questions about the information they uncover.

Fox, Chris

136

Acid fog  

SciTech Connect

Fog in areas of southern California previously thought to be pollution-free has been shown to have a pH as low as 1.69. It has been found to be most acidic after smoggy days, suggesting that it forms on the aerosol associated with the previously exiting smog. Studies on Whiteface Mountain in the Adirondacks show that fog water is often 10 times as acidic as rainwater. As a result of their studies, California plans to spend $4 million on acid deposition research in the coming year. (JMT)

Hileman, B.

1983-03-01

137

ACID RAIN  

EPA Science Inventory

Acid precipitation has become one of the major environmental problems of this decade. It is a challenge to scientists throughout the world. Researchers from such diverse disciplines as plant pathology, soil science, bacteriology, meteorology and engineering are investigating diff...

138

Acidic precipitation  

SciTech Connect

At the International Symposium on Acidic Precipitation, over 400 papers were presented, and nearly 200 of them are included here. They provide an overview of the present state of the art of acid rain research. The Conference focused on atmospheric science (monitoring, source-receptor relationships), aquatic effects (marine eutrophication, lake acidification, impacts on plant and fish populations), and terrestrial effects (forest decline, soil acidification, etc.).

Martin, H.C.

1987-01-01

139

Acid sphingomyelinase.  

PubMed

The enzyme acid sphingomyelinase catalyzes the hydrolysis of sphingomyelin to ceramide. The importance of the enzyme for cell functions was first recognized in Niemann-Pick disease type A and B, the genetic disorders with a massive accumulation of sphingomyelin in many organs. Studies in the last years demonstrated that the enzyme also has an important role in cell signalling. Thus, the acid sphingomyelinase has a central function for the re-organization of molecules within the cell upon stimulation and thereby for the response of cells to stress and the induction of cell death but also proliferation and differentiation. Here, we discuss the current state of the art of the structure, regulation, and function of the acid sphingomyelinase. PMID:23579450

Henry, Brian; Ziobro, Regan; Becker, Katrin Anne; Kolesnick, Richard; Gulbins, Erich

2013-01-01

140

Salicylic acids  

PubMed Central

Salicylic acid is well known phytohormone, emerging recently as a new paradigm of an array of manifestations of growth regulators. The area unleashed yet encompassed the applied agriculture sector to find the roles to strengthen the crops against plethora of abiotic and biotic stresses. The skipped part of integrated picture, however, was the evolutionary insight of salicylic acid to either allow or discard the microbial invasion depending upon various internal factors of two interactants under the prevailing external conditions. The metabolic status that allows the host invasion either as pathogenesis or symbiosis with possible intermediary stages in close systems has been tried to underpin here. PMID:22301975

Hayat, Shamsul; Irfan, Mohd; Wani, Arif; Nasser, Alyemeni; Ahmad, Aqil

2012-01-01

141

Acid Stomach  

NSDL National Science Digital Library

This Science NetLinks lesson is intended for a high-school, introductory chemistry class or health class. The lesson begins with an article on the history of the development of aspirin. Students will then complete a lab that compares the reaction of regular aspirin, buffered aspirin, and enteric aspirin in neutral, acidic, and basic solutions. They will then analyze the results of the experiment to gain insight into how this information was used by researchers to solve some of the problems associated with aspirin. To complete the lesson, students must understand acids and bases.

Science Netlinks;

2003-08-07

142

Sucrose phosphorylases catalyze transglycosylation reactions on carboxylic acid compounds  

Microsoft Academic Search

Two sucrose phosphorylases were employed for glycosylation of carboxylic acid compounds. Streptococcus mutans sucrose phosphorylase showed remarkable transglycosylating activity, especially under acidic conditions. Leuconostoc mesenteroides sucrose phosphorylase exhibited very weak transglycosylating activity. Three main products were detected from the reaction\\u000a mixture using benzoic acid and sucrose as an acceptor and a donor molecule, respectively. These compounds were identified\\u000a as 1-O-benzoyl

Kazuhisa Sugimoto; Koji Nomura; Hiromi Nishiura; Kohji Ohdan; Takahisa Nishimura; Hideo Hayashi; Takashi Kuriki

2008-01-01

143

Acid rain  

Microsoft Academic Search

The book describes numerous environmental problems which are the result of emissions from coal combustion, petroleum products combustion, petroleum refining, and non-ferrous smelting. The effects of acid rain on soils, plants, water, aquatic ecosystems, and building materials are described. Studies are discussed which show that wind currents are carrying emissions to locations far from the source, with social, economic, and

Ostmann; R. Jr

1982-01-01

144

Acid rain  

SciTech Connect

An overview is presented of acid rain and the problems it causes to the environment worldwide. The acidification of lakes and streams is having a dramatic effect on aquatic life. Aluminum, present in virtually all forest soils, leaches out readily under acid conditions and interferes with the gills of all fish, some more seriously than others. There is evidence of major damage to forests in European countries. In the US, the most severe forest damage appears to be in New England, New York's Adirondacks, and the central Appalachians. This small region is part of a larger area of the Northeast and Canada that appears to have more acid rainfall than the rest of the country. It is downwind from major coal burning states, which produce about one quarter of US SO/sub 2/ emissions and one sixth of nitrogen oxide emissions. Uncertainties exist over the causes of forest damage and more research is needed before advocating expensive programs to reduce rain acidity. The President's current budget seeks an expansion of research funds from the current $30 million per year to $120 million.

Not Available

1984-06-01

145

Microcalorimetric studies of the action on four organic acids in Radix isatidis on the growth of microorganisms.  

PubMed

The actions of four organic acids in Radix isatidis, a traditional Chinese medicinal (TCM) herb, on Escherichia coli, Staphylococcus aureus and Shigella dysenteriae growth were investigated by microcalorimetry. The four organic acids were syringic acid, 2-amino-benzoic acid, salicylic acid and benzoic acid. The power-time curves of Escherichia coli, Staphylococcus aureus and Shigella dysenteriae growth with and without organic acids were acquired, meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k1, k2), maximum heat-output[0] power (P(m)) and peak time (t(m)). The inhibitory activity varied with different drugs. The sequences of anti-microbial activity of the four organic acids on Escherichia coli, Staphylococcus aureus and Shigella dysenteriae were all: syringic acid > 2-amino-benzoic acid > salicylic acid > benzoic acid. And benzoic acid promoted the growth of Staphylococcus aureus and Shigella dysenteriae. This study provides a basis for the further study on Radix Isatidis. PMID:18616177

Kong, Weijun; Zhao, Yanling; Shan, Limei; Xiao, Xiaohe; Guo, Weiying

2008-04-01

146

Domoic Acid  

NSDL National Science Digital Library

This highly detailed chemical information page features domoic acid, a toxin associated with Amnesic shellfish poisoning and naturally produced by the red algae Chondria armata and diatoms of the genus Pseudo-nitzschia. Created by the International Programme on Chemical Safety, this web page organizes information under the following sections: Name, Summary, Physio-Chemical Properties, Uses, Routes of Entry, Kinetics, Toxicology, Toxicological and Biomedical Investigations, Clinical Effects, Management, Illustrative Cases, Additional Information, References, and Authors.

Inchem; Safety, International P.

147

Comparative detoxication. The detoxication of aromatic acids by invertebrates: detection of agmatine conjugates in scorpions.  

PubMed

1. Benzoic acid and p-nitrobenzoic acid were converted in the scorpion Palamnaeus into N(1)-benzoylagmatine and N(1)-p-nitrobenzoylagmatine. 2. Some benzoyl- and p-nitrobenzoyl-arginine were also formed and these compounds were probable precursors of the agmatine derivatives. 3. p-Nitrobenzoyl- and p-aminobenzoyl-arginine were formed in millipedes dosed with the aromatic acids. 4. Woodlice excreted p-amino- and p-nitro-benzoic acid as their glycine conjugates and no conjugation could be found in the crab Gecarcinus and a freshwater crayfish Astacus. PMID:5911522

Hitchcock, M; Smith, J N

1966-03-01

148

Acid Ocean  

NSDL National Science Digital Library

The I2I-Acid Ocean virtual lab is an e-learning activity where students become virtual scientists studying the impact of ocean acidification on sea urchin larval growth. Students recreate a real, up-to-date climate change experiment. They also learn important general scientific principles, such as the importance of sample size and numbers of replicates, and discuss what this research into a specific impact of climate change may mean for the future of our oceans. There is a French translation available.

149

Methylmalonic acid blood test  

MedlinePLUS

... acid is a substance produced when proteins (called amino acids) in the body break down. A test can ... Cederbaum S, Berry GT. Inborn errors of carbohydrate, ammonia, amino acid, and organic acid metabolism. In: Gleason CA, Devaskar ...

150

Understanding Acid Rain  

ERIC Educational Resources Information Center

The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

Damonte, Kathleen

2004-01-01

151

Brnsted Acids The Strongest Isolable Acid**  

E-print Network

Brønsted Acids The Strongest Isolable Acid** Mark Juhasz, Stephan Hoffmann, Evgenii Stoyanov, Kee-Chan Kim, and Christopher A. Reed* Acids based on carborane anions as conjugate bases (Figure 1) are a new class of Brønsted (protic) acids, notable for their "strong yet gentle" qualities.[1] For example

Reed, Christopher A.

152

Acid rain  

SciTech Connect

Acid rain, says Boyle is a chemical leprosy eating into the face of North America and Europe, perhaps the major ecological problem of our time. Boyle describes the causes and scope of the phenomenon; the effects on man, wildlife, water, and our cultural heritage. He probes the delays of politicians and the frequent self-serving arguments advanced by industry in the face of what scientists have proved. The solutions he offers are to strengthen the Clean Air Act and require emission reductions that can be accomplished by establishing emission standards on a regional or bubble basis, burn low-sulfur coal, install scrubbers at critical plants, and invest in alternative energy sources. 73 references, 1 figure.

Boyle, R.H.; Boyle, R.A.

1983-01-01

153

Hydrogen Peroxide Stimulates Salicylic Acid Biosynthesis in Tobacco  

Microsoft Academic Search

Hydrogen peroxide induced the accumulation of free benzoic acid (BA) and salicylic acid (SA) in tobacco (Nicotiana fabacum L. cv Xanthi-nc) leaves. Six hours after infiltration with 300 mM H202, the levels of BA and SA in leaves increased 5-fold over the levels detected in control leaves. The accumulation of BA and SA was preceded by the rapid activation of

José León; Michael A. Lawton

154

New method of acidizing or acid fracturing: crosslinked acid gels  

SciTech Connect

Acid polymer gels having pH less than one have been crosslinked for retarding the chemical and physical activity of hydrochloric acid on calcareous formations. Hydrochloric acid concentrations from .0025 to 28% have been successfully crosslinked. This stimulation fluid offers high viscosity with adequate shear stability, perfect support for proppants, and clay stabilization. Additionally, the fluid provides effective fluid loss control and retardation of acid reaction enabling live acid to penetrate deeper into the formation for better formation conductivity and practically a residue-free break for rapid clean-up of the well after the job. Results of lab and field tests show the acid crosslinked system to be an effective stimulation fluid for acidizing and acid fracturing in calcareous and sandstone formations having low formation permeability.

Pabley, A.S.; Holcomb, D.L.

1980-01-01

155

Vibrational coupling in carboxylic acid dimers  

NASA Astrophysics Data System (ADS)

The vibrational level splitting in the ground electronic state of carboxylic acid dimers mediated by the doubly hydrogen-bonded networks are investigated using pure and mixed dimers of benzoic acid with formic acid as molecular prototypes. Within the 0-2000-cm-1 range, the frequencies for the fundamental and combination vibrations of the two dimers are experimentally measured by using dispersed fluorescence spectroscopy in a supersonic jet expansion. Density-functional-theory calculations predict that most of the dimer vibrations are essentially in-phase and out-of-phase combinations of the monomer modes, and many of such combinations show significantly large splitting in vibrational frequencies. The infrared spectrum of the jet-cooled benzoic acid dimer, reported recently by Bakker et al. [J. Chem. Phys. 119, 11180 (2003)], has been used along with the dispersed fluorescence spectra to analyze the coupled g-u vibrational levels. Assignments of the dispersed fluorescence spectra of the mixed dimer are suggested by comparing the vibronic features with those in the homodimer spectrum and the predictions of density-functional-theory calculation. The fluorescence spectra measured by excitations of the low-lying single vibronic levels of the mixed dimer reveal that the hydrogen-bond vibrations are extensively mixed with the ring modes in the S1 surface.

Nandi, Chayan K.; Hazra, Montu K.; Chakraborty, Tapas

2005-09-01

156

Ionic equilibria in aqueous organic solvent mixtures the dissociation constants of acids and salts in tetrahydrofuran\\/water mixtures  

Microsoft Academic Search

The dissociation constants of several acids (perchloric, hydrochloric, phosphoric, acetic and benzoic acids) and of some sodium salts (chloride, acetate and benzoate) have been conductometrically determined in tetrahydrofuran\\/water mixtures up to a 90% of tetrahydrofuran in volume. The results demonstrate that conductometry can be successfully applied to determine the dissociation constants of salts and moderately weak and strong acids in

Urmas Muinasmaa; Clara Ràfols; Elisabeth Bosch; Martí Rosés

1997-01-01

157

Rediscovering Arsenoacetic Acid.  

E-print Network

??Arsonoacetic acid, H?O?As¹CH?COOH, and arsenoacetic acid, punitively [AsVCH?COOH]? have been synthesised according to historical literature methods, and have been characterised using modern techniques. Arsonoacetic acid… (more)

Wilson, Peter Stanley

2009-01-01

158

Organic acids tunably catalyze carbonic acid decomposition.  

PubMed

Density functional theory calculations predict that the gas-phase decomposition of carbonic acid, a high-energy, 1,3-hydrogen atom transfer reaction, can be catalyzed by a monocarboxylic acid or a dicarboxylic acid, including carbonic acid itself. Carboxylic acids are found to be more effective catalysts than water. Among the carboxylic acids, the monocarboxylic acids outperform the dicarboxylic ones wherein the presence of an intramolecular hydrogen bond hampers the hydrogen transfer. Further, the calculations reveal a direct correlation between the catalytic activity of a monocarboxylic acid and its pKa, in contrast to prior assumptions about carboxylic-acid-catalyzed hydrogen-transfer reactions. The catalytic efficacy of a dicarboxylic acid, on the other hand, is significantly affected by the strength of an intramolecular hydrogen bond. Transition-state theory estimates indicate that effective rate constants for the acid-catalyzed decomposition are four orders-of-magnitude larger than those for the water-catalyzed reaction. These results offer new insights into the determinants of general acid catalysis with potentially broad implications. PMID:24933150

Kumar, Manoj; Busch, Daryle H; Subramaniam, Bala; Thompson, Ward H

2014-07-10

159

Density functional theory study of the oligomerization of carboxylic acids.  

PubMed

We present a density functional theory [M06-2X/6-31+G(d,p)] study of the structures and free energies of formation of oligomers of four carboxylic acids (formic acid, acetic acid, tetrolic acid, and benzoic acid) in water, chloroform, and carbon tetrachloride. Solvation effects were treated using the SMD continuum solvation model. The low-lying energy structures of molecular complexes were located by adopting an efficient search procedure to probe the potential energy surfaces of the oligomers of carboxylic acids (CA)n (n = 2-6). The free energies of the isomers of (CA)n in solution were determined as the sum of the electronic energy, vibrational-rotational-translational gas-phase contribution, and solvation free energy. The assessment of the computational protocol adopted in this study with respect to the dimerization of acetic acid, (AA)2, and formic acid, (FA)2, located new isomers of (AA)2 and (FA)2 and gave dimerization constants in good agreement with the experimental values. The calculation of the self-association of acetic acid, tetrolic acid, and benzoic acid shows the following: (i) Classic carboxylic dimers are the most stable isomer of (CA)2 in both the gas phase and solution. (ii) Trimers of carboxylic acid are stable in apolar aprotic solvents. (iii) Molecular clusters consisting of two interacting classic carboxylic dimers (CA)4,(D+D) are the most stable type of tetramers, but their formation from the self-association of classic carboxylic dimers is highly unfavorable. (iv) For acetic acid and tetrolic acid the reactions (CA)2 + 2CA ? (CA)4,(D+D) and (CA)3 + CA ? (CA)4,(D+D) are exoergonic, but these aggregation pathways go through unstable clusters that could hinder the formation of tetrameric species. (v) For tetrolic acid the prenucleation species that are more likely to form in solution are dimeric and trimeric structures that have encoded structural motifs resembling the ? and ? solid forms of tetrolic acid. (vi) Stable tetramers of benzoic acid could form in carbon tetrachloride from the aggregation of trimers and monomers. (vii) Higher order clusters such as acetic acid pentamers and tetrolic acid hexamers are highly unstable in all solvation environments. PMID:25357019

Di Tommaso, Devis; Watson, Ken L

2014-11-20

160

Direct preparation of nitriles from carboxylic acids in continuous flow.  

PubMed

A continuous-flow protocol for the preparation of organic nitriles from carboxylic acids has been developed. The method is based on the acid-nitrile exchange reaction with acetonitrile, used as the solvent, and takes place without any catalyst or additives under the high-temperature/high-pressure conditions employed. At 350 °C and 65 bar, where acetonitrile is in its supercritical state, the transformation of benzoic acid to benzonitrile requires 25 min. The protocol has been tested for a variety of nitriles, including aromatic and aliphatic substrates. PMID:24066706

Cantillo, David; Kappe, C Oliver

2013-10-18

161

Acid Rain Study Guide.  

ERIC Educational Resources Information Center

Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid

Hunger, Carolyn; And Others

162

Formic Acid Mechanical,  

E-print Network

and engineering. Products will range from starch, to polylactic acid, to corn fiber, to motor fuels. ProgressiveFormic Acid Fire Ant Starch Mechanical, Industrial Chemical, Petroleum Biological What Do systems. Fire ants make formic acid. U of I researchers are developing fuel cells that use formic acid (1

Illinois at Urbana-Champaign, University of

163

Sulphuric Acid Manufacture  

Microsoft Academic Search

The raw material for sulphuric acid manufacture is clean SO2 gas. It comes from (i) burning molten by-product sulphur; (ii) roasting or smelting metal sulphide concentrates, and (iii) decomposing contaminated organic chemical process sulphuric acid catalyst. Efficient gas cleaning is required for metallurgical and contaminated acid decomposition gases, especially the former. Sulphuric acid is made from SO2 gas by (i)

W. G. Davenport; M. J. King; B. Rogers; A. Weissenberger

2006-01-01

164

Noncovalent-bonded 1D-3D supramolecular architectures from 2-methylquinoline/quinoline with monocarboxylic acid and dicarboxylic acid  

NASA Astrophysics Data System (ADS)

Studies concentrating on noncovalent weak interactions between the organic base of 2-methylquinoline/quinoline, and carboxylic acid derivatives have led to an increased understanding of the role 2-methylquinoline/quinoline have in binding with carboxylic acids. Here anhydrous multicomponent organic acid-base adducts of 2-methylquinoline/quinoline have been prepared with carboxylic acids that ranged from monocarboxylic acid to dicarboxylic acid such as p-nitrobenzoic acid, (4-chloro-phenoxy)-acetic acid, 4-hydroxy-benzoic acid, 5-bromosalicylic acid, 2,4-dihydroxybenzoic acid, ?-ketoglutaric acid, and 4-nitrophthalic acid. The seven crystalline complexes were characterized by X-ray diffraction analysis, IR, m.p., and elemental analysis. These structures adopted the hetero supramolecular synthons. Analysis of the crystal packing of 1-7 suggests that there are Nsbnd H⋯O, Osbnd H⋯N, and Osbnd H⋯O hydrogen bonds (charge assisted or neutral) between the acid and quinoline moieties in the studied compounds. Except the classical hydrogen bonding interactions, the secondary propagating interactions also play important roles in structure extension. These weak interactions combined, these compounds displayed 1D-3D framework structure.

Gao, Xingjun; Jin, Shouwen; Jin, Li; Ye, XiangHang; Zheng, Lu; Li, JingWen; Jin, BinPeng; Wang, Daqi

2014-10-01

165

Asphaltene damage in matrix acidizing  

E-print Network

were acidized with three stage treatments of 15% hydrochloric acid (HCl), 12% HCL-3% hydrofluoric acid (HF) and 15% HCL. No additives were used in the acid. Comparisons were made between cores acidized with a variety of saturating fluids. Petrographic...

Hinojosa, Roberto Antonio

2012-06-07

166

Peroxy acid epoxidation of acyclic allylic alcohols. Competition between s-trans and s-cis peroxy acid conformers.  

PubMed

[Reaction: see text]. RB3LYP calculations, reported here, indicate that peroxy acid s-cis conformer is more stable than its s-trans counterpart, in agreement with experimental data. Difference in stability is the highest in the gas phase, but it falls considerably on going from the gas phase to moderately polar solvent. In the case of peroxy formic acid, the enthalpy (free energy) difference is about 3.4 (2.5) kcal/mol, respectively, in the gas phase but decreases to 1.2 (0.6) kcal/mol in dichloromethane solution. Introduction of an alkyl or aryl substituent on the peroxy acid, that is, on passing to peroxy acetic, peroxy benzoic (PBA), and m-chloroperoxy benzoic acid (MCPBA), adds a further significant (1.0-1.5 kcal/mol) favor to the s-cis isomer. RB3LYP/6-31+G(2d,p) calculations on the epoxidation of 2-propenol with peroxy formic and peroxy benzoic acids, respectively, suggest that the less stable peroxy acid s-trans conformer can compete with the more stable s-cis form in epoxidation reaction of these substrates. Transition structures arising from s-trans peroxy acids ("trans" TSs) retain both the well-established, for "cis" TS, perpendicular orientation of the O-H peroxy acid bond relative to the C=C bond and the one-step oxirane ring formation. These TSs collapse to the final epoxide via a 1,2-H shift at variance with the 1,4-H transfer of the classical Bartlett's "cis" mechanism. The "trans" reaction pathways have a higher barrier in the gas phase than the "cis" reaction channels, but in moderately polar solvents they become competitive. In fact, the "trans" TSs are always significantly more stabilized than their "cis" counterparts by solvation effects. Calculations also suggest that going from peroxy formic to peroxy benzoic acid should slightly disfavor the "trans" route relative to the "cis" one, reflecting, in an attenuated way, the decrease in the peroxy acid s-trans/s-cis conformer ratio. The predicted behavior for MCPBA parallels that of PBA acid. PMID:16268635

Freccero, Mauro; Gandolfi, Remo; Sarzi-Amadè, Mirko; Rastelli, Augusto

2005-11-11

167

Free and chemically bonded phenolic acids in barks of Viburnum opulus L. and Sambucus nigra L.  

PubMed

Liquid column chromatography, planar chromatography (TLC) on modified and unmodified silica layers, reversed-phase high-pressure liquid chromatography (HPLC), as well as ESI-TOF MS and 1H-NMR have been used for separation, purification and identification of phenolic acids in the barks of Sambucus nigra and Viburnum opulus (Caprifoliaceae). By the use of these procedures three cinnamic acid derivatives: caffeic acid, p-coumaric, and ferulic acid, four benzoic acid derivatives: gallic acid, protocatechuic acid, syringic acid, 3,4,5-trimethoxybenzoic acid, two phenylacetic acid derivatives: 3,4-dihydroxyphenylacetic acid, homogentisic acid, and two depsides: chlorogenic acid and ellagic acid were detected and identified in the bark of Viburnum opulus. Caffeic acid, p-coumaric acid, ferulic acid, gallic acid, syringic acid, 3,4,5-trimethoxybenzoic acid and chlorogenic acid were also detected and identified in the bark of Sambucus nigra. Except for chlorogenic acid, this is the first time these phenolic acids have been isolated, detected, and identified in the bark of V. opulus and S. nigra. PMID:18536165

Turek, Sebastian; Cisowski, Wojciech

2007-01-01

168

Quantity of acid in acid fog  

SciTech Connect

This communication notes the actual magnitude of the acidity in acidic fog particles and suggests a possible line of inquiry into the health effects of such fog so that it can be determined whether a typical fog is detrimental or beneficial relative to dry air.

Deal, W.J.

1983-07-01

169

New bioactive fatty acids.  

PubMed

Many oxygenated fatty acids are bioactive compounds. Nocardia cholesterolicum and Flavobacterium DS5 convert oleic acid to 10 hydroxy stearic acid and linoleic acid to 10-hydroxy-12(Z)-octadecanoic acid. Pseudomonas aeruginosa PR3 converts oleic acid to the new compounds, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) through 10-hydroxy-8-octadecenoic acid, and racinoleic acid to 7,10,12-trihydroxy-8-octadecenoic acid. DOD showed antibacterial activity including against food-borne pathogens. Bacillus megaterium ALA2 converted n-6 and n-3 PUFAs to many new oxygenated fatty acids. For example: linoleic acid was converted to12,13-epoxy-9-octadecenoic acid and then to 12,13-dihydroxy-9-octadecenoic acid (12,13-DHOA). From here, there are two bioconversion pathways. The major pathway is: 12,13-DHOA --> 12,13,17-trihydroxy-9(S)-octadecenoic acid (THOA) --> 12,17;13,17-diepoxy-16-hydroxy-9(Z)-octadecenoic acid (DEOA) --> 7-hydroxy-DEOA. The minor pathway is: 12,13-DHOA --> 12,13,16-THOA --> 12-hydroxy-13,16-epoxy-9(Z)-octadecenoic acid. 12,13,17-THOA has anti-plant pathogenic fungal activity. The tetrahydrofuranyl moiety is known in anti cancer drugs. Strain ALA2 also converts other n-3 and n-6 PUFAs such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) to many new oxygenated unsaturated fatty acid products. All of these new products have high potential for antimicrobial agents or biomedical applications. We also screened 12 Mortierella fungal strains from the ARS Culture Collection for the production of bioactive fatty acids such as dihomo-gama-linolenic acid (DGLA) and arachidonic acid. All of the strains tested produced AA and DGLA from glucose or glycerol. The top five AA producers (mg AA/g CDW) were in the following order: M. alpina > M. zychae > M. hygrophila > M. minutissima > M. parvispora. Both AA and DGLA are important natural precursors of a large family of prostaglandin and thromboxane groups. PMID:18296335

Hou, Ching T

2008-01-01

170

Fatty acid analogs  

DOEpatents

In one aspect, a radioactively labeled analog of a fatty acid which is capable of being taken up by mammalian tissue and which exhibits an in vivo beta-oxidation rate below that with a corresponding radioactively labeled fatty acid.

Elmaleh, David R. (Newton Center, MA); Livni, Eli (Brookline, MA)

1985-01-01

171

Plasma amino acids  

MedlinePLUS

Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Laboratory error High or low amounts of individual plasma amino acids must be considered with other information. ...

172

Citric acid urine test  

MedlinePLUS

... usually done while you are on a normal diet. Ask your health care provider for more information. ... A low level of citric acid may mean renal tubular acidosis and a ... acid levels: A high carbohydrate diet Estrogen therapy Vitamin D

173

Plant fatty acid hydroxylases  

DOEpatents

This invention relates to plant fatty acyl hydroxylases. Methods to use conserved amino acid or nucleotide sequences to obtain plant fatty acyl hydroxylases are described. Also described is the use of cDNA clones encoding a plant hydroxylase to produce a family of hydroxylated fatty acids in transgenic plants. In addition, the use of genes encoding fatty acid hydroxylases or desaturases to alter the level of lipid fatty acid unsaturation in transgenic plants is described.

Somerville, Chris (Portola Valley, CA); Broun, Pierre (Burlingame, CA); van de Loo, Frank (Lexington, KY)

2001-01-01

174

Acid rain agreement  

Microsoft Academic Search

Scientific working groups from Canada and the US have been established to prepare for acid rain negotiations scheduled for June 1981. The groups will take air samples and estimate impact of acid rain on the environment, determine the precise origin of acid rain, and develop a strategy for abatement. Some constraints on the negotiations are costs (potentially $400-500 million for

R. J. SMITH

1980-01-01

175

[alpha]-Oxocarboxylic Acids  

ERIC Educational Resources Information Center

Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH…

Kerber, Robert C.; Fernando, Marian S.

2010-01-01

176

What Is Acid Rain?  

ERIC Educational Resources Information Center

Acid rain is the collective term for any type of acidified precipitation: rain, snow, sleet, and hail, as well as the presence of acidifying gases, particles, cloud water, and fog in the atmosphere. The increased acidity, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion of fossil fuels such as coal and oil.…

Likens, Gene E.

2004-01-01

177

Acid (and Base) Rainbows  

NSDL National Science Digital Library

Learners use red cabbage juice and pH indicator paper to test the acidity and basicity of household materials. The activity links this concept of acids and bases to acid rain and other pollutants. Resource contains vocabulary definitions and suggestions for assessment, extensions, and scaling for different levels of learners.

Kolenbrander, Amy; Yowell, Janet; Mach, Natalie; Zarske, Malinda S.; Carlson, Denise; Perez, Sharon

2004-01-01

178

Quantity of acid in acid fog  

SciTech Connect

The chemical composition of fog particles has become of considerable interest, because of both the possibility of interpreting atmospheric- chemistry processes in fog particles in terms of the principles of aqueous chemistry and the potential health effects of species present in fog particles. The acidity of fog particles has received wide attention. This communication noted the actual magnitude of the excess acidity in acidic fog particles and suggested a possible line of inquiry into the health effects of such fog so that it can be determined whether a typical fog is detrimental or beneficial relative to dry air. (DP)

Deal, W.J.

1983-07-01

179

Adsorption of aromatic organic acids onto high area activated carbon cloth in relation to wastewater purification  

Microsoft Academic Search

Adsorption of aromatic organic acids: benzoic acid (BA), salicylic acid (SA), p-aminobenzoic acid (pABA) and nicotinic acid (NA), onto high area activated carbon cloth from solutions in 0.4M H2SO4, in water at natural pH, in 0.1M NaOH and also from solutions having pH 7.0 were studied by in situ UV-spectroscopic technique. The first-order rate law was found to be applicable

Erol Ayranci; Osman Duman

2006-01-01

180

Solid compounds of europium and terbium with some aromatic carboxylic acids  

SciTech Connect

By the reactions of europium and terbium hydroxides with aqueous solutions of benzoic, salicylic, phthalic, and phthalaldehydic acids, compounds were obtained with the compositions: for phthalic acid M/sub 2/L/sub 3/ x 3H/sub 2/O, and for the other acids ML/sub 3/ x 3H/sub 2/O, in which M = Eu/sup 3 +/, Tb/sup 3 +/; L is the anion of the corresponding acid. The compounds of europium and terbium with phthalaldehydric acid were prepared for the first time.

Chupakhina, R.A.; Biryulina, V.N.; Kasimova, L.V.; Balakhonov, V.G.

1986-10-20

181

Acid Strengths of Some Substituted Picric Acids.  

National Technical Information Service (NTIS)

The aqueous dissociation constants for a number of substituted picric acids and related compounds were determined spectrophotometrically, and the values obtained correlated with the mid-equivalence potentials obtained by half-neutralization in acetone sol...

P. J. Pearce, R. J. J. Simkins

1968-01-01

182

Abscisic Acid ELISA: Organic Acid Interference 1  

PubMed Central

Consideration must be exercised in determination of buffers and solutions used when carrying out enzyme-linked immunosorbent assays (ELISAs). A commercial monoclonal antibody kit for abscisic acid (Idetek, Inc.) gives significant false-positives with tricarboxylic acid cycle intermediates. The organic acids or contaminants interfered with ELISA assays for ABA as indicated by deviations in the slopes of standard curves of ABA in the organic acids. The interference, in the case of ?-ketoglutarate, was caused by a contaminant. Of the organic buffers tested—Tris, Tricine, and Hepes—only Hepes showed false-positive ABA. In addition, we present data indicating the presence of ABA in commercial mannitol and provide a simple procedure for removal of the ABA. PMID:16667202

Belefant, Helen; Fong, Franklin

1989-01-01

183

Editorial: Acid precipitation  

SciTech Connect

This editorial focuses on acid rain and the history of public and governmental response to acid rain. Comments on a book by Gwineth Howell `Acid Rain and Acid Waters` are included. The editor feels that Howells has provide a service to the environmental scientific community, with a textbook useful to a range of people, as well as a call for decision makers to learn from the acid rain issue and use it as a model for more sweeping global environmental issues. A balance is needed among several parameters such as level of evidence, probability that the evidence will lead to a specific direction and the cost to the global community. 1 tab.

NONE

1995-09-01

184

Amino acid analysis  

NASA Technical Reports Server (NTRS)

The process and apparatus for qualitative and quantitative analysis of the amino acid content of a biological sample are presented. The sample is deposited on a cation exchange resin and then is washed with suitable solvents. The amino acids and various cations and organic material with a basic function remain on the resin. The resin is eluted with an acid eluant, and the eluate containing the amino acids is transferred to a reaction vessel where the eluant is removed. Final analysis of the purified acylated amino acid esters is accomplished by gas-liquid chromatographic techniques.

Winitz, M.; Graff, J. (inventors)

1974-01-01

185

EXTRACTIONOFTERVALENTLANTHANIDESWITH ACIDIC ORGANOPHOSPHORUS COMPOUNDS  

Microsoft Academic Search

The equilibrium.extraction behavior for a series of tervalent lanthanide ions (Ln) using a chloroform solution containing di(2-ethyl-hexyl) phosphoric acid (HDEHP), diphenylphosphinic acid (HDPP), dibutylphosphorothioic acid (HDBPT), di-n-octylphosphorodithoic acid (HDOPDT), or di(2-ethylhexyl)phosphorodithioic acid (HDEHPDT), either alone or combined with adduct forming agents is studied. The extracted species are Ln(DEHP) 3(HDEHP) 3, Ln(DPP)3 (HDPP)3, Ln(DBPT)3, and are Ln(DBPT)3(HDERP)3 in the presence of

Shoji Motomizu; Henry Freiser

1985-01-01

186

Selective extraction of succinic acid from binary mixture of succinic acid and acetic acid  

Microsoft Academic Search

In production of succinic acid by fermentation, succinic acid and acetic acid are co-produced. To purify the succinic acid from binary-acid mixture of succinic acid and acetic acid, the tertiary amine-based extraction was used. In 1-octanol, the selectivity for succinic acid was proportional to the chain length of tertiary amine. But, the distribution of acids into organic phase was low

Yeon Ki Hong; Won Hi Hong; Ho Nam Chang

2000-01-01

187

Demospongic Acids Revisited  

PubMed Central

The well-known fatty acids with a ?5,9 unsaturation system were designated for a long period as demospongic acids, taking into account that they originally occurred in marine Demospongia sponges. However, such acids have also been observed in various marine sources with a large range of chain-lengths (C16–C32) and from some terrestrial plants with short acyl chains (C18–C19). Finally, the ?5,9 fatty acids appear to be a particular type of non-methylene-interrupted fatty acids (NMA FAs). This article reviews the occurrence of these particular fatty acids in marine and terrestrial organisms and shows the biosynthetic connections between ?5,9 fatty acids and other NMI FAs. PMID:21116406

Kornprobst, Jean-Michel; Barnathan, Gilles

2010-01-01

188

NRPSs and amide ligases producing homopoly(amino acid)s and homooligo(amino acid)s.  

PubMed

Microorganisms are capable of producing a wide variety of biopolymers. Homopoly(amino acid)s and homooligo(amino acid)s, which are made up of only a single type of amino acid, are relatively rare; in fact, only two homopoly(amino acid)s have been known to occur in nature: poly(?-L-lysine) (?-PL) and poly(?-glutamic acid) (?-PGA). Bacterial enzymes that produce homooligo(amino acid)s, such as L-?-lysine-, L-valine-, L-leucine-, L-isoleucine-, L-methionine-, and L-glutamic acid-oligopeptides and poly(?-l-glutamic acid) (?-PGA) have recently been identified, as well as ?-PL synthetase and ?-PGA synthetase. This article reviews the current knowledge about these unique enzymes producing homopoly(amino acid)s and homooligo(amino acid)s. PMID:23817633

Hamano, Yoshimitsu; Arai, Toshinobu; Ashiuchi, Makoto; Kino, Kuniki

2013-08-01

189

THE ACTIVATION OF STARFISH EGGS BY ACIDS.  

PubMed

1. Exposure of unfertilized starfish eggs to dilute solutions of weak acids (fatty acids, benzoic and carbonic acids) in isotonic balanced salt solution causes complete activation with the proper durations of exposure. For each acid the rate of activation (reciprocal of optimum duration) varies with concentration and temperature; at a given temperature and within a considerable range of concentrations (e.g. 0.00075 to 0.004 M for butyric acid), this rate is approximately proportional to concentration. We may thus speak of a molecular rate of action characteristic of each acid. 2. In general the molecular rate of action increases with the dissociation constant and surface activity of the acids. In the fatty acid series (up to caproic), formic acid has the most rapid effect, acting about four times as rapidly as acetic; for the other acids the order is: acetic = propionic <== butyric < valeric < caproic. Carbonic acid acts qualitatively like the fatty acids, but its molecular rate of action is only about one-fourteenth that of acetic acid. 3. Hydrochloric and lactic acids are relatively ineffective as activating agents, apparently because of difficulty of penetration. Lactic acid is decidedly the more effective. The action of both acids is only slightly modified by dissolving in pure (isotonic NaCl and CaCl(2)) instead of in balanced salt solution. 4. The rate of action of acetic acid, in concentrations of 0.002 M to 0.004 M is increased (by 10 to 20 per cent) by adding Na-acetate (0.002 to 0.016) to the solution. The degree of acceleration is closely proportional to the estimated increase in undissociated acetic acid molecules. Activation thus appears to be an effect of the undissociated acid molecules in the external solution and not of the ions. Acetate anions and H ions acting by themselves, in concentrations much higher than those of the solutions used, have no activating effect. The indications are that the undissociated molecules penetrate rapidly, the ions slowly. Having penetrated, the molecules dissociate inside the egg, yielding the ions of the acid. 5. When the rate of activation is slow, as in 0.001 M acetic acid, the addition of Na-acetate (0,008 M to 0.016 M) has a retarding effect, referable apparently to the gradual penetration of acetate ions to the site of the activation reaction with consequent depression of dissociation. 6. An estimate of the C(H) of those solutions (of the different activating acids) which activate the egg at the same rate indicates that their H ion concentrations are approximately equal. On the assumptions that only the undissociated molecules penetrate readily, and that the conditions of dissociation are similar inside and outside the egg, this result indicates (especially when the differences in adsorption of the acids are considered) that the rate of activation is determined by the C(H) at the site of the activation reaction within the egg. PMID:19872205

Lillie, R S

1926-04-20

190

The antimicrobial activities of the cinnamaldehyde adducts with amino acids.  

PubMed

Cinnamaldehyde is a well-established natural antimicrobial compound. It is probable for cinnamaldehyde to react with amino acid forming Schiff base adduct in real food system. In this paper, 9 such kind of adducts were prepared by the direct reaction of amino acids with cinnamaldehyde at room temperature. Their antimicrobial activities against Bacillus subtilis, Escherichia coli and Saccharomyces cerevisiae were evaluated with benzoic acid as a reference. The adducts showed a dose-dependent activities against the three microbial strains. Both cinnamaldehyde and their adducts were more active against B. subtilis than on E. coli, and their antimicrobial activities were higher at lower pH. Both cinnamaldehyde and its adducts were more active than benzoic acid at the same conditions. The adduct compound A was non-toxic by primary oral acute toxicity study in mice. However, in situ effect of the adduct compound A against E. coli was a little lower than cinnamaldehyde in fish meat. This paper for the first time showed that the cinnamaldehyde adducts with amino acids had similar strong antimicrobial activities as cinnamaldehyde, which may provide alternatives to cinnamaldehyde in food to avoid the strong unacceptable odor of cinnamaldehyde. PMID:21856030

Wei, Qing-Yi; Xiong, Jia-Jun; Jiang, Hong; Zhang, Chao; Wen Ye

2011-11-01

191

Use of organic acids and salts to control postharvest diseases of lemon fruits in Egypt  

Microsoft Academic Search

Postharvest diseases caused by Geotricum candidum (sour rot), Penicillium digitatum (green mould), and P. italicum (blue mould) are the most important negative factors affecting handling and marketing of citrus fruits in Egypt. The effect of organic acids (ascorbic, benzoic, citric and sorbic) as well as organic salts (potassium sorbate and sodium benzoate) were evaluated on the growth of causal agents

Nehal S. El-Mougy; Nadia G. El-Gamal; F. Abd-El-Kareem

2008-01-01

192

Acid rain reports  

NASA Astrophysics Data System (ADS)

Three independent reports on acid precipitation issued in June reinforce each other and, taken together, support those seeking immediate action to curb man-generated acid deposition in northeastern North America by reducing emissions of sulfur and nitrogen oxides. The Interagency Task Force on Acid Precipitation report concluded that manmade pollution is to blame for acid precipitation problems in the northeastern United States. A National Research Council (NRC) committee stated that reducing the manmade emissions of sulfur and nitrogen oxides will result in a proportional reduction in the deposition of acid precipitation. And an acid rain panel assembled by the White House Office of Science and Technology Policy (OSTP) called for immediate action to curb the emissions despite incomplete scientific data.

Richman, Barbara T.

193

Lewis acid organocatalysts.  

PubMed

Abstract The term Lewis acid catalysts generally refers to metal salts like aluminium chloride, titanium chloride and zinc chloride. Their application in asymmetric catalysis can be achieved by the addition of enantiopure ligands to these salts. However, not only metal centers can function as Lewis acids. Compounds containing carbenium, silyl or phosphonium cations display Lewis acid catalytic activity. In addition, hypervalent compounds based on phosphorus and silicon, inherit Lewis acidity. Furthermore, ionic liquids, organic salts with a melting point below 100 degrees C, have revealed the ability to catalyze a range of reactions either in substoichiometric amount or, if used as the reaction medium, in stoichiometric or even larger quantities. The ionic liquids can often be efficiently recovered. The catalytic activity of the ionic liquid is explained by the Lewis acidic nature of their cations. This review covers the survey of known classes of metal-free Lewis acids and their application in catalysis. PMID:21494948

Sereda, Oksana; Tabassum, Sobia; Wilhelm, René

2010-01-01

194

Lewis Acid Organocatalysts  

NASA Astrophysics Data System (ADS)

The term Lewis acid catalysts generally refers to metal salts like aluminium chloride, titanium chloride and zinc chloride. Their application in asymmetric catalysis can be achieved by the addition of enantiopure ligands to these salts. However, not only metal centers can function as Lewis acids. Compounds containing carbenium, silyl or phosphonium cations display Lewis acid catalytic activity. In addition, hypervalent compounds based on phosphorus and silicon, inherit Lewis acidity. Furthermore, ionic liquids, organic salts with a melting point below 100 °C, have revealed the ability to catalyze a range of reactions either in substoichiometric amount or, if used as the reaction medium, in stoichiometric or even larger quantities. The ionic liquids can often be efficiently recovered. The catalytic activity of the ionic liquid is explained by the Lewis acidic nature of their cations. This review covers the survey of known classes of metal-free Lewis acids and their application in catalysis.

Sereda, Oksana; Tabassum, Sobia; Wilhelm, René

195

Acid Rain Learning Activities  

NSDL National Science Digital Library

These suggestions for activities allow students to learn about acid deposition in new and interactive ways, both in and out of the classroom. The suggestions are for individuals and small groups, the class as a whole, or for field trips. Students may contact local experts about acid rain issues, investigate the energy sources used to generate electricity by their local power companies, collect cartoons about acid rain and air pollution, or play the roles of scientists or interested parties involved in investigations of acid rain issues. Field trip ideas include visiting a local museum or science center to see exhibits or resources on acid rain, and visiting a local cemetary to examine the effects of acid rain on the headstones.

196

Production of methanol from aromatic acids by Pseudomonas putida.  

PubMed Central

When grown at the expense of 3,4,5-trimethoxybenzoic acid, a strain of Pseudomonas putida oxidized this compound and also 3,5-dimethoxy-4-hydroxybenzoic (syringic) and 3,4-dihydroxy-5-methoxybenzoic (3-O-methylgallic) acids; but other hydroxy- or methoxy-benzoic acids were oxidized slowly or not at all. Radioactivity appeared exclusively in carbon dioxide when cells were incubated with [4-methoxyl-14C]trimethoxybenzoic acid, but was found mainly in methanol when[methoxyl-14C]3-O-methylgallic acid was metabolized. The identity of methanol was proved by analyzing the product from [methoxyl-13C]3-O-methylgallic acid by nuclear magnetic resonance spectroscopy and by isolating the labeled 3,5-dinitrobenzoic acid methyl ester, which was examined by mass spectrometry. These results, together with measurements of oxygen consumed in demethylations catalyzed by cell extracts, showed that two methoxyl groups of 3,4,5-trimethoxybenzoate and one of syringate were oxidized to give carbon dioxide and 3-O-methylgallate. This was then metabolized to pyruvate; the other product was presumed to be the 4-methyl ester of oxalacetic acid, for which cell extracts contained an inducible, specific esterase. P. putida did not metabolize the methanol released from this compound by hydrolysis. Support for the proposed reaction sequence was obtained by isolating mutants which, although able to convert 3,4,5-trimethoxybenzoic acid into 3-O-methylgallic acid, were unable to use either compound for growth. PMID:7380811

Donnelly, M I; Dagley, S

1980-01-01

197

Bile Acid Metabolism  

Microsoft Academic Search

\\u000a Bile acids are physiological agents that facilitate biliary secretion of lipids and metabolites, and intestinal absorption\\u000a of fat and nutrients. Bile acids are also signaling molecules that activate nuclear receptors and cell signaling pathways\\u000a to regulate hepatic lipid metabolism and homeostasis. Bile acids are synthesized from cholesterol in the liver, stored in\\u000a the gallbladder, secreted to the intestine and reabsorbed

John Y. L. Chiang

198

Acid rain on Bermuda  

Microsoft Academic Search

Increased acidity of precipitation due to combustion of fossil fuels has been well documented for both the eastern USA1 and Canada2. The SO2 and NOxemitted by the burning of coal, natural gas, fuel oil and petrol are oxidized in the atmosphere to sulphuric and nitric acids which subsequently give rise to acid precipitation1. However, the SO2 and NOx emitted, and

Timothy Jickells; Anthony Knap; Thomas Church; James Galloway; John Miller

1982-01-01

199

Acid-Base Solutions  

NSDL National Science Digital Library

How do strong and weak acids differ? Use lab tools on your computer to find out! Dip the paper or the probe into solution to measure the pH, or put in the electrodes to measure the conductivity. Then see how concentration and strength affect pH. Can a weak acid solution have the same pH as a strong acid solution?

Simulations, Phet I.; Lancaster, Kelly; Malley, Chris; Loeblein, Patricia; Parson, Robert; Perkins, Kathy

2010-09-01

200

DEOXYRIBONUCLEIC ACID HYBRIDS OF ACETIC ACID BACTERIA  

PubMed Central

De Ley, J. (State University, Ghent, Belgium), and S. Friedman. Deoxyribonucleic acid hybrids of acetic acid bacteria. J. Bacteriol. 88:937–945. 1964.—Deuterated N15-labeled deoxyribonucleic acid (DNA) from Acetobacter aceti (mesoxydans 4) forms hybrids with ordinary DNA from other species of this genus (A. xylinum, A. pasteurianus, A. estunensis, and possibly A. xylinoides) when the guanine plus cytosine base composition does not vary by more than 1 to 2%. Beyond this limit (A. aceti Ch31 and A. muciparus 5) no hybrids are formed. The hybrids are apparently derived from an asymmetrical part of the compositional distribution. The results lend strength to the concept of a genetic species rather than to a division of a genus into sharply separated species, based on small phenotypic differences. Taxonomic implications are discussed. PMID:14219057

De Ley, J.; Friedman, S.

1964-01-01

201

Improved taxol yield by aromatic carboxylic acid and amino acid feeding to cell cultures of taxus cuspidata.  

PubMed

Cell culture of Taxus cuspidata represents an alternative to whole plant extraction as a source of taxol and related taxanes. Feeding phenylalanine to callus cultures was previously shown to result in increased taxol yields, probably due to the involvement of this amino acid as a precursor for the N-benzoylphenylisoserine side chain of taxol. Inthis study, we have examined the effect of various concentrations of phenylalanine, benzoic acid, N-benzoylglycine, serine, glycine, alanine, and 3-amino-3-phenyl-propionic acid on taxol accumulation in 2-year-old cell suspensions of Taxus cuspidata, cell line FCL1F, and in developing callus cultures of T. cuspidata. All compounds tested were included in media at stationary phase (suspensions) or after the period of fastest growth (calli). Alanine and 3-amino-3-phenyl-propionicacid were tested only in callus cultures and did not affect taxol accumulation. Significant increases or trends toward increases in taxol accumulationin callus and suspensions were observed in the presence of phenylalanine, benzoic acid, N-benzoylglycine, serine, and glycine. The greatest increases in taxol accumulation were observed in the presence of various concentrations of phenylalanine (1 mM for callus; 0.05, 0.1, and 0.2 mM for suspensions) and benzoic acid (0.2 and 1 mM for callus and 0.05, 0.1, and 0.2 mM for suspensions). Increases in taxol yields of cell suspensions in the presence of the most effective precursors brought taxol amounts at stationary phase from 2 mug . g(-1) to approximately 10 mug . g(-1) of the extracted dry weight. The results are discussed in termsof possible implications to taxol biosynthesis and in terms of practical applications to large-scale cell culture systems for the production ofthis drug. (c) 1994 John Wiley & Sons, Inc. PMID:18618915

Fett-Neto, A G; Melanson, S J; Nicholson, S A; Pennington, J J; Dicosmo, F

1994-10-01

202

Uric Acid Test  

MedlinePLUS

... purine metabolism . Metastatic cancer, multiple myeloma , leukemias , and cancer chemotherapy can cause increased production of uric acid. Chronic renal disease , acidosis , toxemia of pregnancy , and alcoholism can cause ...

203

Empirical method for consideration of solvent effect on the dissociation constants of carboxylic acids  

Microsoft Academic Search

An empirical method was used to calculate 363 dissociation constants of 33 benzoic and acetic acid derivatives in 11 solvents.\\u000a The relative error in the calculations did not exceed 9.5%, and the average error was no higher than 3%. The calculated values\\u000a were compared with those obtained by quantum-chemical and other methods for determination of acid dissociation constants in\\u000a different

Yu. E. Zevatskii; D. V. Samoilov

2008-01-01

204

Molecular Structure of Fumaric acid  

NSDL National Science Digital Library

Fumaric acid is odorless and colorless or white crystalline powder with a fruit acid taste. Fumaric acid is used as a substitute of tartaric acid in beverages and baking powders and as a replacement for citric acid in fruits drinks. It is also used as antioxidant to prevent rancidity in butter, cheese, powdered milk, and other foodstuff. In addition, fumaric acid is a chemical intermediate in the manufacture of pharmaceuticals, synthetic resins and plastics. Fumaric acid can be prepared by catalytic oxidation of benzene or by bacterial action on glucose and it is involved in the production of energy from food. Fumaric acid (known as trans-butanedioic acid) is the trans isomer of maleic acid (also called cis-butanedioic acid). Fumaric acid is more stable than maleic acid and can be prepared by heating maleic acid.

2004-11-05

205

Regioselective hydroxylation of quinolinic acid, lutidinic acid and isocinchomeronic acid by resting cells of pyridine dicarboxylic acid-degrading microorganisms  

Microsoft Academic Search

Microorganisms aerobically degrading quinolinic acid, lutidinic acid or isocinchomeronic acid were isolated and the microbial regioselective hydroxylation of these pyridine dicarboxylic acids was studied. Alcaligenes sp. UK21 cells converted quinolinic acid into 6-hydroxypicolinic acid, suggesting the involvement of two enzyme reactions catalyzing hydroxylation at position C6 and decarboxylation at position C3 of quinolinic acid. Resting cells of Alcaligenes sp. UK21

A. Uchida; T. Yoshida; M. Ogawa; T. Nagasawa

2003-01-01

206

Neutralizing Acids and Bases  

NSDL National Science Digital Library

In this activity, students will use their knowledge of color changes with red cabbage indicator to neutralize an acidic solution with a base and then neutralize a basic solution with an acid. This website includes a student activity sheet and additional student readings.

2010-01-01

207

(Acid rain workshop)  

Microsoft Academic Search

The traveler presented a paper entitled Susceptibility of Asian Ecosystems to Soil-Mediated Acid Rain Damage'' at the Second Workshop on Acid Rain in Asia. The workshop was organized by the Asian Institute of Technology (Bangkok, Thailand), Argonne National Laboratory (Argonne, Illinois), and Resource Management Associates (Madison, Wisconsin) and was sponsored by the US Department of Energy, the United Nations Environment

1990-01-01

208

Acid rain: Controllable?  

Microsoft Academic Search

Acid rain is one of a growing number of environmental issues in which impacts are far removed from the source o f the irritants. Those who suffer may differ in geographical area from those who benefit from the activity which releases pollution to the atmosphere. Like the issue concerning the depletion of ozone by manufactured chemicals, the acid rain issue

Lester Machta

1983-01-01

209

Mounting acid rain  

Microsoft Academic Search

The incidence of acid rain at some distance from the initial source of pollution is expected to increase as more plants are converted to burn coal and stacks are built higher to relieve local pollution problems. The alkaline soils of the West neutralize most of the effects of acid rain, making the problem less acute than in the eastern US.

1979-01-01

210

EFFECTS OF ACID PRECIPITATION  

EPA Science Inventory

Recent reviews of available data indicate that precipitation in a large region of North America is highly acidic when its pH is compared with the expected pH value of 5.65 for pure rain water in equilibrium with CO2. A growing body of evidence suggests that acid rain is responsib...

211

Iodinated humic acids  

NASA Astrophysics Data System (ADS)

Humic acids are iodinated by elemental iodine and, if the iodine is present as iodide, by peroxidase-mediated reactions. It is demonstrated that iodination of humic acids leads to a product with a uniform distribution of iodine. It could not be unambiguously verified whether the enzymatically mediated iodination is a direct reaction between a peroxidase-iodine complex and the humic acid molecule or a two-step reaction in which the enzyme creates elemental iodine, which consecutively reacts with the humic acid. Based on a simple model of a reaction between sites in the humic acids available for iodination and the electrophilic iodinating species, it was concluded that the reaction should be described as an equilibrium with a logarithmic equilibrium constant of approximately 4. The number of sites available for iodination was, in the humic acids studied, determined to be approximately 4×10-4 per gram humic acid. The different parameters influencing the enzymatically controlled iodination of humic acids are discussed.

Christiansen, Jesper V.; Carlsen, Lars

212

Controlling acid rain  

E-print Network

High concentrations of sulfuric and nitric acid in raTn fn the northeastern USA are caused by the large scale combustion of fossil fuels within this region. Average precipitation acidity is pH 4.2, but spatial and temporal ...

Fay, James A.

1983-01-01

213

Bile acid transporters  

PubMed Central

In liver and intestine, transporters play a critical role in maintaining the enterohepatic circulation and bile acid homeostasis. Over the past two decades, there has been significant progress toward identifying the individual membrane transporters and unraveling their complex regulation. In the liver, bile acids are efficiently transported across the sinusoidal membrane by the Na+ taurocholate cotransporting polypeptide with assistance by members of the organic anion transporting polypeptide family. The bile acids are then secreted in an ATP-dependent fashion across the canalicular membrane by the bile salt export pump. Following their movement with bile into the lumen of the small intestine, bile acids are almost quantitatively reclaimed in the ileum by the apical sodium-dependent bile acid transporter. The bile acids are shuttled across the enterocyte to the basolateral membrane and effluxed into the portal circulation by the recently indentified heteromeric organic solute transporter, OST?-OST?. In addition to the hepatocyte and enterocyte, subgroups of these bile acid transporters are expressed by the biliary, renal, and colonic epithelium where they contribute to maintaining bile acid homeostasis and play important cytoprotective roles. This article will review our current understanding of the physiological role and regulation of these important carriers. PMID:19498215

Dawson, Paul A.; Lan, Tian; Rao, Anuradha

2009-01-01

214

ACID AEROSOLS ISSUE PAPER  

EPA Science Inventory

The report evaluates scientific information on direct health effects associated with exposure to acid aerosols. The present report is not intended as a complete and detailed review of all literature pertaining to acid aerosols. Rather, an attempt has been made to focus on the eva...

215

Lead-acid batteries  

Microsoft Academic Search

A method of producing a lead-acid battery capable of activation by the addition of electrolyte thereto, comprises the steps of: starting with a battery container accommodating at least one pack of battery plate grids having insulating separators interposed between adjacent grids, each of said grids carrying the lead-acid battery paste required to produce a positive or a negative battery plate

J. A. Bant; V. J. Raban

1980-01-01

216

Urobilinogen AscorbicAcid  

E-print Network

Date Lot # Bilirubin Urobilinogen Ketone AscorbicAcid Glucose Protein Blood pH Nitrite Leukocytes Specific Gravity hCG: Method Lot # Acetest® (Ketone): Lot # Clinitest® (Glucose): Lot # Ictotest®(Bilirubin AND DATA ENTRY FORMS #12;Date Lot # Bilirubin Urobilinogen Ketone AscorbicAcid Glucose Protein Blood p

Rodriguez, Carlos

217

Acid Rain Revisited  

NSDL National Science Digital Library

The results of a long term study of the effects of acidic deposition in the Northeast were published in Bioscience this week, and they suggest that forests, lakes, and streams of the Northeastern US are not recovering from the toxic effects of acid rain despite significant cuts in the power plant emissions of sulfur dioxide and nitrogen oxide -- two major contributors to the problem. "Acid rain," more accurately called acidic deposition, causes toxic forms of aluminum to concentrate in soil and water, vital calcium and magnesium to be leached from trees, and surface waters to become inhospitable to aquatic biota. The study showed that, after 30 years of federally mandated air emission reductions, sulfur dioxide emissions have decreased while nitrogen oxide emissions have remained the same and that acidic deposition-related problems continue to plague New York and New England.

Sanders, Hilary C.

2001-01-01

218

Acid rain trends summarized  

NASA Astrophysics Data System (ADS)

In the northeastern United States, the acidity of precipitation has changed little in recent years, although the acidity is increasing in other regions. That's the latest word from a comprehensive review by the U.S. Geological Survey (USGS) of more than 200 published reports of acid rain research from the past 30 years. The report contributes to the controversy over whether increased sulfur emissions from Midwest powerplants increase the acidity of precipitation in the Northeast.“When the results of the many individual studies are combined, they show that acidification of precipitation in the Northeast, which has the most damaging level of acidity on a regional basis, occurred primarily before the mid-1950's and has been largely stabilized since the mid-1960s,” said John T. Turk, a research hydrologist at the USGS Denver office and author of the 18-page summary report.

219

Fatty Acid Production from Amino Acids and ?-Keto Acids by Brevibacterium linens BL2†  

PubMed Central

Low concentrations of branched-chain fatty acids, such as isobutyric and isovaleric acids, develop during the ripening of hard cheeses and contribute to the beneficial flavor profile. Catabolism of amino acids, such as branched-chain amino acids, by bacteria via aminotransferase reactions and ?-keto acids is one mechanism to generate these flavorful compounds; however, metabolism of ?-keto acids to flavor-associated compounds is controversial. The objective of this study was to determine the ability of Brevibacterium linens BL2 to produce fatty acids from amino acids and ?-keto acids and determine the occurrence of the likely genes in the draft genome sequence. BL2 catabolized amino acids to fatty acids only under carbohydrate starvation conditions. The primary fatty acid end products from leucine were isovaleric acid, acetic acid, and propionic acid. In contrast, logarithmic-phase cells of BL2 produced fatty acids from ?-keto acids only. BL2 also converted ?-keto acids to branched-chain fatty acids after carbohydrate starvation was achieved. At least 100 genes are potentially involved in five different metabolic pathways. The genome of B. linens ATCC 9174 contained these genes for production and degradation of fatty acids. These data indicate that brevibacteria have the ability to produce fatty acids from amino and ?-keto acids and that carbon metabolism is important in regulating this event. PMID:15528496

Ganesan, Balasubramanian; Seefeldt, Kimberly; Weimer, Bart C.

2004-01-01

220

Conjugated Fatty Acid Synthesis  

PubMed Central

Conjugated linolenic acids (CLNs), 18:3 ?9,11,13, lack the methylene groups found between the double bonds of linolenic acid (18:3 ?9,12,15). CLNs are produced by conjugase enzymes that are homologs of the oleate desaturases FAD2. The goal of this study was to map the domain(s) within the Momordica charantia conjugase (FADX) responsible for CLN formation. To achieve this, a series of Momordica FADX-Arabidopsis FAD2 chimeras were expressed in the Arabidopsis fad3fae1 mutant, and the transformed seeds were analyzed for the accumulation of CLN. These experiments identified helix 2 and the first histidine box as a determinant of conjugase product partitioning into punicic acid (18:3 ?9cis,11trans,13cis) or ?-eleostearic acid (18:3 ?9cis,11trans,13trans). This was confirmed by analysis of a FADX mutant containing six substitutions in which the sequence of helix 2 and first histidine box was converted to that of FAD2. Each of the six FAD2 substitutions was individually converted back to the FADX equivalent identifying residues 111 and 115, adjacent to the first histidine box, as key determinants of conjugase product partitioning. Additionally, expression of FADX G111V and FADX G111V/D115E resulted in an approximate doubling of eleostearic acid accumulation to 20.4% and 21.2%, respectively, compared with 9.9% upon expression of the native Momordica FADX. Like the Momordica conjugase, FADX G111V and FADX D115E produced predominantly ?-eleostearic acid and little punicic acid, but the FADX G111V/D115E double mutant produced approximately equal amounts of ?-eleostearic acid and its isomer, punicic acid, implicating an interactive effect of residues 111 and 115 in punicic acid formation. PMID:22451660

Rawat, Richa; Yu, Xiao-Hong; Sweet, Marie; Shanklin, John

2012-01-01

221

Total syntheses of cis-cyclopropane fatty acids: dihydromalvalic acid, dihydrosterculic acid, lactobacillic acid, and 9,10-methylenehexadecanoic acid.  

PubMed

cis-Cyclopropane fatty acids (cis-CFAs) are widespread constituents of the seed oils of subtropical plants, membrane components of bacteria and protozoa, and the fats and phospholipids of animals. We describe a systematic approach to the synthesis of enantiomeric pairs of four cis-CFAs: cis-9,10-methylenehexadecanoic acid, lactobacillic acid, dihydromalvalic acid, and dihydrosterculic acid. The approach commences with Rh2(OAc)4-catalyzed cyclopropenation of 1-octyne and 1-decyne, and hinges on the preparative scale chromatographic resolution of racemic 2-alkylcycloprop-2-ene-1-carboxylic acids using a homochiral Evan's auxiliary. Saturation of the individual diastereomeric N-cycloprop-2-ene-1-carbonylacyloxazolidines, followed by elaboration to alkylcyclopropylmethylsulfones, allowed Julia-Kocienski olefination with various ?-aldehyde-esters. Finally, saponification and diimide reduction afforded the individual cis-CFA enantiomers. PMID:25321346

Shah, Sayali; White, Jonathan M; Williams, Spencer J

2014-12-14

222

Optical properties in the UV and visible spectral region of organic acids relevant to tropospheric aerosols  

NASA Astrophysics Data System (ADS)

Refractive and absorption indices in the UV and visible region of selected aqueous organic acids relevant to tropospheric aerosols are reported. The acids investigated are the aliphatic dicarboxylic acids oxalic, malonic, tartronic, succinic and glutaric acid. In addition we report data for pyruvic, pinonic, benzoic and phthalic acid. To cover a wide range of conditions we have investigated the aqueous organic acids at different concentrations spanning from highly diluted samples to concentrations close to saturation. The density of the investigated samples is reported and a parameterisation of the absorption and refractive index that allows the calculation of the optical constants of mixed aqueous organic acids at different concentrations is presented. The single scattering albedo is calculated for two size distributions using measured and a synthetic set of optical constants. The results show that tropospheric aerosols consisting of only these organic acids and water have a pure scattering effect.

Lund Myhre, C. E.; Nielsen, C. J.

2004-06-01

223

Optical properties in the UV and visible spectral region of organic acids relevant to tropospheric aerosols  

NASA Astrophysics Data System (ADS)

Refractive and absorption indices in the UV and visible region of selected aqueous organic acids relevant to tropospheric aerosols are reported. The acids investigated are the aliphatic dicarboxylic acids oxalic, malonic, tartronic, succinic and glutaric acid. In addition we report data for pyruvic, pinonic, benzoic and phthalic acid. To cover a wide range of conditions we have investigated the aqueous organic acids at different concentrations spanning from highly diluted samples to concentrations close to saturation. The density of the investigated samples is reported and a parameterisation of the absorption and refractive index that allows the calculation of the optical constants of mixed aqueous organic acids at different concentrations is presented. The single scattering albedo is calculated for two size distributions using measured and a synthetic set of optical constants. The results show that tropospheric aerosols consisting of only these organic acids and water have a pure scattering effect.

Lund Myhre, C. E.; Nielsen, C. J.

2004-09-01

224

Synthesis of (+)- and (?)-Phaselic Acid  

Microsoft Academic Search

The synthesis of both enantiomers of phaselic acid (2-O-caffeoylmalate) is described. The previously unreported acetate protected caffeic acid anhydride was used with appropriately protected malic acid derivatives as coupling partners to provide fully protected phaselic acid. Sequential unmasking of the protecting groups afforded phaselic acid in an acceptable overall yield.

Wayne E. Zeller

2012-01-01

225

Sulfuric Acid on Europa  

NASA Technical Reports Server (NTRS)

Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain.

This image is based on data gathered by Galileo's near infrared mapping spectrometer.

Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks.

Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

1999-01-01

226

Acid recovery from waste sulfuric acid by diffusion dialysis  

Microsoft Academic Search

In the process of sulfuric acid production from pyrite, there is a lot of waste acid produced in fume washing with dilute\\u000a acid. Acid recovery from this sort of waste sulfuric acid by diffusion dialysis is studied in the paper. The mass transfer\\u000a dialysis coefficient of sulfuric acid of the membrane AFX is measured, the effect of the flowrate of

Guiqing Zhang; Qixiu Zhang; Kanggen Zhou

1999-01-01

227

Strongly Acidic Auxin Indole-3-Methanesulfonic Acid  

PubMed Central

A radiochemical synthesis is described for [14C]indole-3-methanesulfonic acid (IMS), a strongly acidic auxin analog. Techniques were developed for fractionation and purification of IMS using normal and reverse phase chromatography. In addition, the utility of both Fourier transform infrared spectrometry and fast atom bombardment mass spectrometry for analysis of IMS has been demonstrated. IMS was shown to be an active auxin, stimulating soybean hypocotyl elongation, bean first internode curvature, and ethylene production. IMS uptake by thin sections of soybean hypocotyl was essentially independent of solution pH and, when applied at a 100 micromolar concentration, IMS exhibited a basipetal polarity in its transport in both corn coleoptile and soybean hypocotyl sections. [14C]IMS should, therefore, be a useful compound to study fundamental processes related to the movement of auxins in plant tissues and organelles. PMID:16664007

Cohen, Jerry D.; Baldi, Bruce G.; Bialek, Krystyna

1985-01-01

228

Ceric acid decontamination of nuclear reactors  

SciTech Connect

This patent describes a composition, it consists of water; about 0.5 to about 3% by weight of a ceric acid selected from the group consisting of tetrasulfato ceric acid, hexasulfamato ceric acid, hexaperchlorato ceric acid, and mixtures thereof; and about 1 to about 5% by weight of an inorganic acid. The inorganic acid is sulfuric acid when the ceric acid is tetrasulfato ceric acid, sulfamic acid when the ceric acid is hexasulfamato ceric acid, perchloric acid when the ceric acid is a mixture selected from the group consisting of tetrasulfato ceric acid, hexasulfamato ceric acid, and hexaperchlorato ceric acid.

Murray, A.P; Slater, C.G.; White, R.W.

1989-11-14

229

Separation of aliphatic carboxylic acids and benzenecarboxylic acids by ion-exclusion chromatography with various cation-exchange resin columns and sulfuric acid as eluent.  

PubMed

The application of various hydrophilic cation-exchange resins for high-performance liquid chromatography (sulfonated silica gel: TSKgel SP-2SW, carboxylated silica gel: TSKgel CM-2SW, sulfonated polymethacrylate resin: TSKgel SP-5PW, carboxylated polymethacrylate resins: TSKgel CM-5PW and TSKgel OA-Pak A) as stationary phases in ion-exclusion chromatography for C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, butyric, isovaleric, valeric, isocaproic, caproic, 2-methylhexanoic and heptanoic acids) and benzenecarboxylic acids (pyromellitic, trimellitic, hemimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic, salicylic acids and phenol) was carried out using diluted sulfuric acid as the eluent. Silica-based cation-exchange resins (TSKgel SP-2SW and TSKgel CM-2SW) were very suitable for the ion-exclusion chromatographic separation of these benzenecarboxylic acids. Excellent simultaneous separation of these benzenecarboxylic acids was achieved on a TSKgel SP-2SW column (150 x 6 mm I.D.) in 17 min using a 2.5 mM sulfuric acid at pH 2.4 as the eluent. Polymethacrylate-based cation-exchange resins (TSKgel SP-5PW, TSKgel CM-5PW and TSKgel OA-Pak A) acted as advanced stationary phases for the ion-exclusion chromatographic separation of these C1-C7 aliphatic carboxylic acids. Excellent simultaneous separation of these C1-C7 acids was achieved on a TSKgel CM-5PW column (150 x 6 mm I.D.) in 32 min using a 0.05 mM sulfuric acid at pH 4.0 as the eluent. PMID:12830883

Ohta, Kazutoku; Ohashi, Masayoshi; Jin, Ji-Ye; Takeuchi, Toyohide; Fujimoto, Chuzo; Choi, Seong-Ho; Ryoo, Jae-Jeong; Lee, Kwang-Pill

2003-05-16

230

Volatile organic acids generated from kerogen during laboratory heating.  

PubMed

Low molecular weight organic acids were studied in the course of pyrolysis experiments (200-400 degrees C, 2-1,000 h) of kerogen (Green River Formation and Monterey Formation) with and without the presence of water and minerals (montmorillonite, illite and calcite). C1-C10 aliphatic acids and benzoic acid were identified in the pyrolysis products of kerogen. Their distribution is characterized by a dominance of acetic acid followed by formic and propionic acids with an even/odd preference in the range of C4-C10. Total concentrations of these acids amounted to 0.3% of initial kerogen, indicating that kerogen has a good potential for producing organic acids. Geochemical implications of these organic acids are; (1) they are possible intermediates from kerogen to natural gas (CO2, H2, CH4, C2H6, etc.) by decarboxylation, and (2) they may be important and potential contributors to the generation of secondary porosity by dissolving minerals. PMID:11542117

Kawamura, K; Tannenbaum, E; Huizinga, B J; Kaplan, I R

1986-01-01

231

Stomach acid test  

MedlinePLUS

Gastric acid secretion test ... The test is done after a period of not eating so that fluid is all that remains in the ... the stomach through the esophagus (food pipe). To test the ability of the cells in the stomach ...

232

ACID RAIN CONTROL OPTIONS  

EPA Science Inventory

The paper discusses acid rain control options available to the electric utility industry. They include coal switching, flue gas desulfurization, and such emerging lower cost technologies as Limestone Injection Multistage Burners (LIMB) and Advanced Silicate (ADVACATE) both develo...

233

Acid-Base Tutorial  

NSDL National Science Digital Library

Website for anyone wanting to become more familiar with the physiology of acid-base balance in clinical medicine. Several pages are interactive. Numerical results are accompanied by text interpretations to facilitate recognition and understanding.

MD Alan W. Grogono (Tulane University School of Medicine Dept. of Anesthesiology)

2002-06-01

234

Folic acid in diet  

MedlinePLUS

... leafy vegetables Dried beans and peas (legumes) Citrus fruits and juices Fortified means that vitamins have been added to the food. Many foods are now fortified with folic acid, including enriched breads, cereals, flours, cornmeals, pastas, rice, ...

235

Acid Lipase Disease  

MedlinePLUS

... Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage Disease, Wolman’s Disease Table of Contents (click to ... include waxes, oils, and cholesterol. Two rare lipid storage diseases are caused by the deficiency of the ...

236

(Acid rain workshop)  

SciTech Connect

The traveler presented a paper entitled Susceptibility of Asian Ecosystems to Soil-Mediated Acid Rain Damage'' at the Second Workshop on Acid Rain in Asia. The workshop was organized by the Asian Institute of Technology (Bangkok, Thailand), Argonne National Laboratory (Argonne, Illinois), and Resource Management Associates (Madison, Wisconsin) and was sponsored by the US Department of Energy, the United Nations Environment Program, the United Nations Economic and Social Commission for Asia and the Pacific, and the World Bank. Papers presented on the first day discussed how the experience gained with acid rain in North America and Europe might be applied to the Asian situation. Papers describing energy use projections, sulfur emissions, and effects of acid rain in several Asian countries were presented on the second day. The remaining time was allotted to discussion, planning, and writing plans for a future research program.

Turner, R.S.

1990-12-05

237

Aminolevulinic Acid Topical  

MedlinePLUS

... under the skin that result from exposure to sunlight and can develop into skin cancer) of the ... acid will make your skin very sensitive to sunlight (likely to get sunburn). Avoid exposure of treated ...

238

Fatty Acid Carcass Mapping  

E-print Network

FATTY ACID CARCASS MAPPING A Thesis by STACEY NICOLE TURK Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 2008... Major Subject: Animal Science FATTY ACID CARCASS MAPPING A Thesis by STACEY NICOLE TURK Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE...

Turk, Stacey N.

2010-01-14

239

Acid-base chemistry  

SciTech Connect

The book is not a research compendium and there are no references to the literature. It is a teaching text covering the entire range of undergraduate subject matter dealing with acid-base chemistry (some of it remotely) as taught in inorganic, analytical, and organic chemistry courses. The excellent chapters VII through IX deal in detail with the quantitative aspects of aqueous acid-base equilibria (salt hydrolysis and buffer, titrations, polyprotic and amphoteric substances).

Hand, C.W.; Blewit, H.L.

1985-01-01

240

Acid Rain Lesson Plan  

NSDL National Science Digital Library

Five articulated lessons focus on air quality using classroom and field data collection activities. Case study in Great Smoky Mountains has broader application. Background and data for lessons on: the pH scale, understanding acid vs. base, collecting data, mapping relationship of weather events to acid rain. Links to NPS data on air quality, current values, atlas and reports, packaged datasets on ozone, meteorological conditions and other parameters. Also available: teacher resources; educator workshops.

241

Portable nucleic acid thermocyclers.  

PubMed

A nucleic acid thermal cycler is considered to be portable if it is under ten pounds, easily carried by one individual, and battery powered. Nucleic acid amplification includes both polymerase chain reaction (e.g. PCR, RT-PCR) and isothermal amplification (e.g. RPA, HDA, LAMP, NASBA, RCA, ICAN, SMART, SDA). There are valuable applications for portable nucleic acid thermocyclers in fields that include clinical diagnostics, biothreat detection, and veterinary testing. A system that is portable allows for the distributed detection of targets at the point of care and a reduction of the time from sample to answer. The designer of a portable nucleic acid thermocycler must carefully consider both thermal control and the detection of amplification. In addition to thermal control and detection, the designer may consider the integration of a sample preparation subsystem with the nucleic acid thermocycler. There are a variety of technologies that can achieve accurate thermal control and the detection of nucleic acid amplification. Important evaluation criteria for each technology include maturity, power requirements, cost, sensitivity, speed, and manufacturability. Ultimately the needs of a particular market will lead to user requirements that drive the decision between available technologies. PMID:24030680

Almassian, David R; Cockrell, Lisa M; Nelson, William M

2013-11-21

242

Mammalian Fatty Acid Elongases  

PubMed Central

Summary Very long chain fatty acids confer functional diversity on cells by variations in their chain length and degree of unsaturation. Microsomal fatty acid elongation represents the major pathway for determining the chain length of saturated, monounsaturated, and polyunsaturated fatty acids in cellular lipids. The overall reaction for fatty acid elongation involves four enzymes and utilizes malonyl CoA, NADPH, and fatty acyl CoA as substrates. While the fundamental pathway and its requirements have been known for many years, recent advances have revealed a family of enzymes involved in the first step of the reaction, i.e., the condensation reaction. Seven fatty acid elongase subtypes (Elovl #1–7) have been identified in the mouse, rat, and human genomes. These enzymes determine the rate of overall fatty acid elongation. Moreover, these enzymes also display differential substrate specificity, tissue distribution, and regulation, making them important regulators of cellular lipid composition as well as specific cellular functions. Herein, methods are described to measure elongase activity, analyze elongation products, and alter cellular elongase expression. PMID:19763486

Jump, Donald B.

2009-01-01

243

Infrared spectra and structure of molecular complexes of aromatic acids  

NASA Astrophysics Data System (ADS)

FTIR spectra of pharmacologically active molecules of benzoic acid and its derivatives have been measured in CCl4 solutions and in microcrystals. Features of the formation of intra-and intermolecular hydrogen bonds have been analyzed. Spectral attributes have been revealed that characterize the participation of a carboxyl group in different types of intermolecular interactions with the formation of cyclic, linear, and criss-cross dimers. Mechanisms of the intermolecular interactions are shown to be defined by the character of the substituents attached to the benzene ring in the para- and meta-positions relative to the carboxylic group.

Belkov, M. V.; Brinkevich, S. D.; Samovich, S. N.; Skornyakov, I. V.; Tolstorozhev, G. B.; Shadyro, O. I.

2012-01-01

244

Reaction of caffeic acid derivatives with acidic nitrite  

Microsoft Academic Search

Caffeic derivatives were reacted with acidic nitrite at controlled pH in order to mimic the gastric juice conditions. At pH 2, whereas caffeic acid reacts exclusively on the side chain, its esters are readily nitrated. Under more acidic conditions (pH 1), caffeic acid methyl ester undergoes a dimerisation into a norlignan derivative.

Philippe Cotelle; Hervé Vezin

2001-01-01

245

Export of Acidity in Drainage Water from Acid Sulphate Soils  

Microsoft Academic Search

Disturbed acid sulphate soils are potent sources of acidity in coastal waterways. Monitoring studies of the drainage water for sites at East Trinity, Cairns and Pimpama, south-east Queensland indicate that considerable acidity is found in the drainage water from these sites. Hydrogen (H+), ferrous (Fe2+) and aluminium (Al) ions are the dominant acid cations involved. When drainage water is mixed

F. J Cook; W Hicks; E. A Gardner; G. D Carlin; D. W Froggatt

2000-01-01

246

What is Acid Rain? Explore the Acid Lake  

NSDL National Science Digital Library

Acid rain is a type of air pollution that occurs when certain chemicals mix with water in the air. Most chemicals that cause acid rain come from the emissions from factories and cars. Acid rain looks just like 'normal' rain but when it falls, it can hurt plants and animals. For example, when acid rain falls into a lake or river, it makes that body of water more acidic. Many plants and animals cannot live in acidic water. Play this game, from Earth Day Canada's EcoKids program, to learn more about acid rain and its impact on the environment.

Canada, Earth D.

2010-01-01

247

Domoic acid epileptic disease.  

PubMed

Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis. PMID:24663110

Ramsdell, John S; Gulland, Frances M

2014-03-01

248

Electrochemical Determination of Lipoic Acid  

Microsoft Academic Search

Procedures for determining lipoic acid by voltammetry and coulometric titration with electrogenerated halogens using the biamperometric indication of the titration end-point were developed. Possible mechanisms of lipoic acid oxidation with electrogenerated halogens are discussed. Microgram amounts of lipoic acid were determined in model solutions with an RSD of 1–2%. The analytical range of lipoic acid found by voltammetry at a

G. K. Ziyatdinova; G. K. Budnikov; V. I. Pogorel'tsev

2004-01-01

249

Atmospheric Dust and Acid Rain  

Microsoft Academic Search

Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid

Lars O. Hedin; Gene E. Likens

1996-01-01

250

Acid Catalysis in Modern Organic  

E-print Network

Acid Catalysis in Modern Organic Synthesis "Acid is one of the oldest, but the most important follows their earlier book "Lewis Acids in Organic Synthesis (2000)", and covers the new developments of university studies, in which an evil-smelling carbox- ylic acid and an alcohol were converted into a fragrant

Snyder, Scott A.

251

Ursodeoxycholic acid, 7-ketolithocholic acid, and chenodeoxycholic acid are primary bile acids of the nutria (Myocastor coypus).  

PubMed

Because ursodeoxycholic and chenodeoxycholic acids are interconverted in humans via 7-ketolithocholic acid, bile acid metabolism was studied in the nutria (Myocastor coypus), the bile of which is known to contain these three bile acids. Relative concentrations of ursodeoxycholic (37% +/- 20%), 7-ketolithocholic (33% +/- 17%), and chenodeoxycholic (17% +/- 9%) acids in gallbladder bile were unchanged by 5-20 h of complete biliary diversion (n = 7). Injection of either [14C]cholesterol, [14C]ursodeoxycholic, [14C]7-ketolithocholic acid, or a mixture of [7 beta-3H]chenodeoxycholic acid and [14C]chenodeoxycholic acid into bile fistula nutria demonstrated that all three bile acids can be synthesized hepatically from cholesterol, that they are interconverted sparingly (2%-5%) by the liver, but that 7-ketolithocholic acid is an intermediate in the hepatic transformation of chenodeoxycholic acid to ursodeoxycholic acid. An animal that had been fed antibiotics showed an unusually elevated concentration of ursodeoxycholic acid in gallbladder and hepatic bile, suggesting that bacterial transformation of ursodeoxycholic acid in the intestine may be a source of some biliary chenodeoxycholic acid and 7-ketolithocholic acid. PMID:3943698

Tint, G S; Bullock, J; Batta, A K; Shefer, S; Salen, G

1986-03-01

252

Nucleophilic reactions of sorbic acid  

Microsoft Academic Search

The conjugated dienoic acid structure of sorbic acid renders it susceptible to nucleophilic attack. Nucleophiles known to react with sorbic acid include sulphite ion and amines. These attack the molecule in position 5 and, in the cse of amines, cyclization to form substituted dihydropyridones may follow. Recent investigations show that thiols in general can also add to sorbic acid. Cysteine,

G. D. Khandelwal; B. L. Wedzicha

1990-01-01

253

DOCOSAHEXAENOIC ACID AND ARACHIDONIC ACID PREVENT ESSENTIAL FATTY ACID DEFICIENCY AND HEPATIC STEATOSIS  

PubMed Central

Objectives Essential fatty acids are important for growth, development, and physiologic function. Alpha-linolenic acid and linoleic acid are the precursors of docosahexaenoic and arachidonic acid, respectively, and have traditionally been considered the essential fatty acids. However, we hypothesized that docosahexaenoic acid and arachidonic acid can function as the essential fatty acids. Methods Using a murine model of essential fatty acid deficiency and consequent hepatic steatosis, we provided mice with varying amounts of docosahexaenoic and arachidonic acids to determine whether exclusive supplementation of docosahexaenoic and arachidonic acids could prevent essential fatty acid deficiency and inhibit or attenuate hepatic steatosis. Results Mice supplemented with docosahexaenoic and arachidonic acids at 2.1% or 4.2% of their calories for 19 days had normal liver histology and no biochemical evidence of essential fatty acid deficiency, which persisted when observed after 9 weeks. Conclusion Supplementation of sufficient amounts of docosahexaenoic and arachidonic acids alone without alpha-linolenic and linoleic acids meets essential fatty acid requirements and prevents hepatic steatosis in a murine model. PMID:22038210

Le, Hau D.; Meisel, Jonathan A.; de Meijer, Vincent E.; Fallon, Erica M.; Gura, Kathleen M.; Nose, Vania; Bistrian, Bruce R.; Puder, Mark

2012-01-01

254

Uranyl monocarboxylates of aromatic acids: a density functional model study of uranyl humate complexation.  

PubMed

Using a scalar relativistic all-electron density functional method, we studied uranium(VI) complexation with benzoic acid and its derivatives in aqueous solution as models of uranyl humates. We explored monodentate, bidentate, and chelate coordination of various isomers of methyl and hydroxyl substituted benzoic acid ligands. Monodentate complexes were determined to be energetically preferred as long as entropy effects were neglected. However, bidentate structures were favored at the Gibbs free energy level. Coordination of aromatic carboxylic acids tends to be weaker than that of aliphatic ones, while structural characteristics were determined to be quite similar. Optimized geometries yield uranyl bonds and U-C distances in agreement with EXAFS results for monocarboxylate of benzoate and p-hydroxy benzoate. Average uranyl-oxygen distances to equatorial ligands, U-O(eq), are shorter than in experiment, which is tentatively rationalized by variations in the coordination numbers. As for aliphatic monocarboxylate complexes studied earlier, U-O(eq) values of benzoic acid derivatives do not discriminate mono- and bidentate coordinated species. Structures and energies determined support the interpretation of uranyl humate complexes as bidentate carboxylate species with fivefold coordination of uranyl. PMID:19381422

Ray, Rupashree Shyama; Krüger, Sven; Rösch, Notker

2009-05-14

255

Molecular Structure of Succinic acid  

NSDL National Science Digital Library

Succinic acid is an odorless and colorless crystal, triclinic or monoclinic prism with a very acid taste. Succinic acid is one of the natural acids found in broccoli, rhubarb, beets, asparagus, fresh meat extracts, sauerkraut and cheese. It is also a constituent of almost all plant and animal tissues and plays an important role in intermediary metabolism. Succinic acid is produced commercially by catalytic hydrogenation of maleic or fumaric acid or by acid hydrolysis of succinonitrile. Succinic acid is used in flavoring for food and beverages, and in the manufacture of lacquers, dyes, esters for perfumes, succinates, in photography and in foods as a sequestrant, buffer and neutralizing agent. Succinic acid has uses in certain drug compounds and in agricultural production. An interesting fact, succcinic acid has also been found in meteorites.

2004-11-11

256

Thiol modified mycolic acids.  

PubMed

Patient serum antibodies to mycolic acids have the potential to be surrogate markers of active tuberculosis (TB) when they can be distinguished from the ubiquitously present cross-reactive antibodies to cholesterol. Mycolic acids are known to interact more strongly with antibodies present in the serum of patients with active TB than in patients with latent TB or no TB. Examples of single stereoisomers of mycolic acids with chain lengths corresponding to major homologues of those present in Mycobacterium tuberculosis have now been synthesised with a sulfur substituent on the terminal position of the ?-chain; initial studies have established that one of these binds to a gold electrode surface, offering the potential to develop second generation sensors for diagnostic patient antibody detection. PMID:23603063

Balogun, Mohammed O; Huws, Enlli H; Sirhan, Muthana M; Saleh, Ahmed D; Al Dulayymi, Juma'a R; Pilcher, Lynne; Verschoor, Jan A; Baird, Mark S

2013-01-01

257

Molecular Structure of Citric Acid  

NSDL National Science Digital Library

Citric Acid was first isolated in 1734 by Carl Wilhelm Scheele. Citric acid is found in many fruits, in particular lemons, grapefruit, and oranges. Several types of bacteria and fungi are also known to produce citric acid. In fact, the fungus Aspergillus niger produces the vast majority of citric acid, which is used in almost all carbonated sodas. Additionally, citric acid is also used to clean stainless steel.

2002-08-13

258

Acid rain degradation of nylon  

Microsoft Academic Search

Acid rain, precipitation with a pH less than 5.6, is known to damage lakes, vegetation and buildings. Degradation of outdoor textiles by acid rain is strongly suspected but not well documented. This study reports the effects of sunlight, aqueous acid, heat and humidity (acid rain conditions) on spun delustered nylon 6,6 fabric. Untreated nylon and nylon treated with sulfuric acid

Kyllo

1984-01-01

259

Liposomal spherical nucleic acids.  

PubMed

A novel class of metal-free spherical nucleic acid nanostructures was synthesized from readily available starting components. These particles consist of 30 nm liposomal cores, composed of an FDA-approved 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid monomer. The surface of the liposomes was functionalized with DNA strands modified with a tocopherol tail that intercalates into the phospholipid layer of the liposomal core via hydrophobic interactions. The spherical nucleic acid architecture not only stabilizes these constructs but also facilitates cellular internalization and gene regulation in SKOV-3 cells. PMID:24983505

Banga, Resham J; Chernyak, Natalia; Narayan, Suguna P; Nguyen, SonBinh T; Mirkin, Chad A

2014-07-16

260

Polyvalent nucleic acid nanostructures.  

PubMed

Polyvalent oligonucleotide-nanoparticle conjugates possess several unique emergent properties, including enhanced cellular uptake, high antisense bioactivity, and nuclease resistance, which hypothetically originate from the dense packing and orientation of oligonucleotides on the surface of the nanoparticle. In this Communication, we describe a new class of polyvalent nucleic acid nanostructures (PNANs), which are comprised of only cross-linked and oriented nucleic acids. We demonstrate that these particles are capable of effecting high cellular uptake and gene regulation without the need of a cationic polymer co-carrier. The PNANs also exhibit cooperative binding behavior and nuclease resistance properties. PMID:21630678

Cutler, Joshua I; Zhang, Ke; Zheng, Dan; Auyeung, Evelyn; Prigodich, Andrew E; Mirkin, Chad A

2011-06-22

261

Polyvalent Nucleic Acid Nanostructures  

PubMed Central

Polyvalent oligonucleotide-nanoparticle conjugates possess several unique emergent properties including enhanced cellular uptake, high antisense bioactivity, and nuclease resistance, which hypothetically originate from the dense packing and orientation of oligonucleotides on the surface of the nanoparticle. In this communication, we describe a new class of polyvalent nucleic acid nanostructures (PNANs), which comprise only crosslinked and oriented nucleic acids. We demonstrate that these particles are capable of effecting high cellular uptake and gene regulation without the need of a cationic polymer co-carrier. The PNANs also exhibit cooperative binding behavior and nuclease resistance properties. PMID:21630678

Cutler, Joshua I.; Zhang, Ke; Zheng, Dan; Auyeung, Evelyn; Prigodich, Andrew E.

2011-01-01

262

The Acid-Base Titration of a Very Weak Acid: Boric Acid  

ERIC Educational Resources Information Center

A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

2012-01-01

263

Ion-exclusion chromatographic behavior of aliphatic carboxylic acids and benzenecarboxylic acids on a sulfonated styrene--divinylbenzene co-polymer resin column with sulfuric acid containing various alcohols as eluent.  

PubMed

The addition of C1-C7 alcohols (methanol, ethanol, propanol, butanol, heptanol, hexanol and heptanol) to dilute sulfuric acid as eluent in ion-exclusion chromatography using a highly sulfonated styrene-divinylbenzene co-polymer resin (TSKgel SCX) in the H+ form as the stationary phase was carried out for the simultaneous separations of both (a) C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, 2-methylvaleric, isocaproic, caproic, 2,2-dimethyl-n-valeric, 2-methylhexanoic, 5-methylhexanoic and heptanoic acids) and (b) benzenecarboxylic acids (pyromellitic, hemimellitic, trimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic and salicylic acids and phenol). Heptanol was the most effective modifier in ion-exclusion chromatography for the improvement of peak shapes and a reduction in retention volumes for higher aliphatic carboxylic acids and benzenecarboxylic acids. Excellent simultaneous separation and relatively highly sensitive conductimetric detection for these C1-C7 aliphatic carboxylic acids were achieved on the TSKgel SCX column (150 x 6 mm I.D.) in 30 min using 0.5 mM sulfuric acid containing 0.025% heptanol as eluent. Excellent simultaneous separation and highly sensitive UV detection at 200 nm for these benzenecarboxylic acids were also achieved on the TSKgel SCX column in 30 min using 5 mM sulfuric acid containing 0.075% heptanol as eluent. PMID:12830881

Ohta, Kazutoku; Towata, Atsuya; Ohashi, Masayoshi

2003-05-16

264

In vitro metabolism of a nitroderivative of acetylsalicylic acid (NCX4016) by rat liver: LC and LC–MS studies  

Microsoft Academic Search

The metabolism of a nitroderivative of acetylsalicylic acid, benzoic acid, 2-(acetyloxy)-3-[(nitrooxy)methyl]phenyl ester (NCX4016), the lead compound of a new class of NO-releasing non steroidal-antiinflammatory drugs has been studied in vitro in rat liver subcellular fractions (S 9000×g, microsomes, cytosol). Samples were extracted with CH3CN (2 vol.) containing 1% H3PO4 (2 M), vortexed for 3 min and then centrifuged for 5

Marina Carini; Giancarlo Aldini; Marica Orioli; Roberto Maffei Facino

2002-01-01

265

[Studies on interaction of acid-treated nanotube titanic acid and amino acids].  

PubMed

Nanotube titanic acid (NTA) has distinct optical and electrical character, and has photocatalysis character. In accordance with these qualities, NTA was treated with acid so as to enhance its surface activity. Surface structures and surface groups of acid-treated NTA were characterized and analyzed by Transmission Electron Microscope (TEM) and Fourier Transform Infrared Spectrometry (FT-IR). The interaction between acid-treated NTA and amino acids was investigated. Analysis results showed that the lengths of acid-treated NTA became obviously shorter. The diameters of nanotube bundles did not change obviously with acid-treating. Meanwhile, the surface of acid-treated NTA was cross-linked with carboxyl or esterfunction. In addition, acid-treated NTA can catch amino acid residues easily, and then form close combination. PMID:20649031

Zhang, Huqin; Chen, Xuemei; Jin, Zhensheng; Liao, Guangxi; Wu, Xiaoming; Du, Jianqiang; Cao, Xiang

2010-06-01

266

Plant fatty acid hydroxylase  

DOEpatents

The present invention relates to the identification of nucleic acid sequences and constructs, and methods related thereto, and the use of these sequences and constructs to produce genetically modified plants for the purpose of altering the composition of plant oils, waxes and related compounds.

Somerville, Chris (Portola Valley, CA); van de Loo, Frank (Lexington, KY)

2000-01-01

267

ACID AEROSOL MEASUREMENT WORKSHOP  

EPA Science Inventory

This report documents the discussion and results of the U.S. EPA Acid Aerosol Measurement Workshop, conducted February 1-3, 1989, in Research Triangle Park, North Carolina. t was held in response to recommendations by the Clean Air Scientific Advisory Committee (CASAC) regarding ...

268

Deoxyribonucleic acid Genetic material  

E-print Network

salt to dissolve them) #12; Precipitate DNA (with ethanol) #12; Species identification VS. #12;Bag#12; Deoxyribonucleic acid Genetic material Chain of molecules linked together DNA contains in Protein Science Published by John Wiley & Sons, Inc. #12; Remove proteins that are bound to DNA (using

Rose, Michael R.

269

Federal Acid Rain Games  

Microsoft Academic Search

Federal environmental policy, designed to control acid rain, is shaped after the hierarchy of the system, and is controlled simultaneously by regional and central governments. Each governmental level controls one of two policy instruments: pollution abatement production and pollution tax. In a two-stage game where regional governments are Stackelberg leaders and control pollution taxes, the subgame perfect equilibrium is socially

Arthur J. Caplan; Emilson C. D. Silva

1999-01-01

270

Acid monitoring kit  

US Patent & Trademark Office Database

An acid monitoring kit is provided which is especially useful for monitoring acid rain. The kit includes a base plate having three discrete areas. One area is provided with a plurality of discrete separable bibulous pH indicator strips, each strip being impregnated with a selected acid-base indicator which is visually recognizable as at least one unique color in each such bibulous pH indicator strip when the bibulous strip is dry, and as a different color upon being wetted with water, the different color being dependent on the pH of the water. A second discrete area is provided with a plurality of color comparison reference standards in a plurality of zones, each zone being of a unique color which corresponds to the color of the water-wetted bibulous pH indictor strip, whereby comparison of the unique color of the pH indicator strip with the unique color of the reference standard provides an indication of the pH of the water. A third discrete area is also labelled to provide the requisite information for the use of such acid monitoring kit to correlate the unique color developed in the bibulous pH indicator strip to a unique color of the reference standard to provide an indication of the pH of the water.

1990-10-02

271

Plant fatty acid hydroxylase  

SciTech Connect

The present invention relates to the identification of nucleic acid sequences and constructs, and methods related to the use of these sequences and constructs to produce genetically modified plants for the purpose of altering the composition of plant oils, waxes and related compounds.

Somerville, C.; Loo, F. van de

2000-02-22

272

Alpha Hydroxy Acids  

MedlinePLUS

... skin or mucous membrane, such as the lips, bear a statement that conveys the following information: Sunburn Alert: This product contains an alpha hydroxy acid (AHA) that may increase your skin's sensitivity to the sun and particularly the possibility of sunburn. Use a ...

273

Molecular Structure of Aspartic Acid  

NSDL National Science Digital Library

Aspartate was first isolated in 1868 from legumin in plant seeds. Aspartic acid forms colorless crystals that are soluble in water and insoluble in alcohols and ethers. This is a naturally occurring nonessential amino acid that is produced in the liver from oxaloacetic acid, but is plentiful in meats and sprouting seeds. The amino acid is important in the Krebs cycle as well as the urea cycle, where it is vital in the elimination of dietary waste products. Aspartic acid is required for stamina, brain and neural health. This acid has been found to be important in the functioning of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and in the production of immunoglobin and antibody synthesis. A deficiency of aspartate will lead to fatigue and depression. Aspartic acid has many uses that include biological and clinical studies, preparation of culture media, and it also functions as a detergent, fungicide, germicide, and metal complexation.

2002-08-20

274

Uric acid inhibits placental system A amino acid uptake.  

PubMed

Hyperuricemia, a common clinical characteristic of preeclamptic pregnancies, has historically been considered a marker of reduced renal function in preeclamptic women. More recently it has been suggested that uric acid may directly contribute to pathological cell signaling events involved in disease progression as well as maternal and fetal pregnancy outcomes including fetal growth restriction. We hypothesize that the increased frequency of restricted fetal growth seen in relation to increasing uric acid concentrations in preeclamptic women is in part the result of uric acid-induced reductions in amino acid transport across the placenta. The objective of the current study was to examine the effects of uric acid on human placental System A amino acid transport using a primary placental villous explant model. Further, we examined the necessity of uric acid uptake and the role of redox signaling as a potential mechanism through which uric acid may attenuate System A activity. Placental uptake of a radiolabeled amino acid analogue, specific to the System A transporter, was reduced in a concentration-dependent fashion with increasing uric acid (0-7 mg/dL), corresponding to uric acid concentrations measured in healthy pregnant and preeclamptic women in the third trimester. Uric acid-induced reduction in System A activity was partially reversed by NADPH oxidase inhibition and completely eliminated by antioxidant treatment. This study demonstrates inhibition of placental System A amino acid transport with uric acid treatment, as a result of uric acid-induced stimulation of intracellular redox signaling cascades. These findings may be relevant to the increased frequency of fetal growth restriction observed in hyperuricemic preeclampsia. Additionally the results of this study, indicating a detrimental effect of hyperuricemia on amino acid transport in the placenta, at concentrations present in women with preeclampsia, also suggest a role for uric acid in the pathophysiology of preeclampsia. PMID:19058847

Bainbridge, S A; von Versen-Höynck, F; Roberts, J M

2009-02-01

275

Uric Acid Inhibits Placental System A Amino Acid Uptake?  

PubMed Central

Hyperuricemia, a common clinical characteristic of preeclamptic pregnancies, has historically been considered a marker of reduced renal function in preeclamptic women. More recently it has been suggested that uric acid may directly contribute to pathological cell signaling events involved in disease progression as well as maternal and fetal pregnancy outcomes including fetal growth restriction. We hypothesize that the increased frequency of restricted fetal growth seen in relation to increasing uric acid concentrations in preeclamptic women is in part the result of uric acid-induced reductions in amino acid transport across the placenta. The objective of the current study was to examine the effects of uric acid on human placental System A amino acid transport using a primary placental villous explant model. Further, we examined the necessity of uric acid uptake and the role of redox signaling as a potential mechanism through which uric acid may attenuate System A activity. Placental uptake of a radiolabeled amino acid analogue, specific to the System A transporter, was reduced in a concentration-dependent fashion with increasing uric acid (0?7 mg/dL), corresponding to uric acid concentrations measured in healthy pregnant and preeclamptic women in the third trimester. Uric acid-induced reduction in System A activity was partially reversed by NADPH oxidase inhibition and completely eliminated by antioxidant treatment. This study demonstrates inhibition of placental System A amino acid transport with uric acid treatment, as a result of uric acid-induced stimulation of intracellular redox signaling cascades. These findings may be relevant to the increased frequency of fetal growth restriction observed in hyperuricemic preeclampsia. Additionally the results of this study, indicating a detrimental effect of hyperuricemia on amino acid transport in the placenta, at concentrations present in women with preeclampsia, also suggest a role for uric acid in the pathophysiology of preeclampsia. PMID:19058847

Bainbridge, S.A.; von Versen-Hoynck, F.; Roberts, J.M.

2009-01-01

276

Specific bile acids inhibit hepatic fatty acid uptake  

PubMed Central

Bile acids are known to play important roles as detergents in the absorption of hydrophobic nutrients and as signaling molecules in the regulation of metabolism. Here we tested the novel hypothesis that naturally occurring bile acids interfere with protein-mediated hepatic long chain free fatty acid (LCFA) uptake. To this end stable cell lines expressing fatty acid transporters as well as primary hepatocytes from mouse and human livers were incubated with primary and secondary bile acids to determine their effects on LCFA uptake rates. We identified ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) as the two most potent inhibitors of the liver-specific fatty acid transport protein 5 (FATP5). Both UDCA and DCA were able to inhibit LCFA uptake by primary hepatocytes in a FATP5-dependent manner. Subsequently, mice were treated with these secondary bile acids in vivo to assess their ability to inhibit diet-induced hepatic triglyceride accumulation. Administration of DCA in vivo via injection or as part of a high-fat diet significantly inhibited hepatic fatty acid uptake and reduced liver triglycerides by more than 50%. In summary, the data demonstrate a novel role for specific bile acids, and the secondary bile acid DCA in particular, in the regulation of hepatic LCFA uptake. The results illuminate a previously unappreciated means by which specific bile acids, such as UDCA and DCA, can impact hepatic triglyceride metabolism and may lead to novel approaches to combat obesity-associated fatty liver disease. PMID:22531947

Nie, Biao; Park, Hyo Min; Kazantzis, Melissa; Lin, Min; Henkin, Amy; Ng, Stephanie; Song, Sujin; Chen, Yuli; Tran, Heather; Lai, Robin; Her, Chris; Maher, Jacquelyn J.; Forman, Barry M.; Stahl, Andreas

2012-01-01

277

[Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography].  

PubMed

The analysis of seven aliphatic carboxylic acids (formic, acetic, propionic, iso-butyric, n-butyric, iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid, perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection. The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column (TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column (TSKgel Super IC-A/C). Good separation was performed on the TSKgel SCX in shorter retention times. For the TSKgel Super IC-A/C, peak shape of the acids was sharp and symmetrical in spite of longer retention times. In addition, the mutual separation of the acids was good except for iso- and n-butyric acids. The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series), lower concentrations of PFBA and sulfuric acid as eluents, non-suppressed conductivity detection and UV detection at 210 nm. This analysis was applied to anaerobic digestion process waters. The chromatograms with conductivity detection were relatively simpler compared with those of UV detection. The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices. PMID:22799193

Ito, Kazuaki; Sakamoto, Jun; Nagaoka, Kazuya; Takayama, Yohichi; Kanahori, Takashi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

2012-04-01

278

Fatty acid-producing hosts  

SciTech Connect

Described are hosts for overproducing a fatty acid product such as a fatty acid. The hosts include an exogenous nucleic acid encoding a thioesterase and, optionally, an exogenous nucleic acid encoding an acetyl-CoA carboxylase, wherein an acyl-CoA synthetase in the hosts are functionally delected. The hosts prefereably include the nucleic acid encoding the thioesterase at an intermediate copy number. The hosts are preferably recominantly stable and growth-competent at 37.degree. C. Methods of producing a fatty acid product comprising culturing such hosts at 37.degree. C. are also described.

Pfleger, Brian F; Lennen, Rebecca M

2013-12-31

279

Acidizing of Sandstone Reservoirs Using HF and Organic Acids  

E-print Network

Mud acid, which is composed of HCl and HF, is commonly used to remove the formation damage in sandstone reservoirs. However, many problems are associated with HCl, especially at high temperatures. Formic-HF acids have served as an alternative...

Yang, Fei

2012-10-19

280

Thiobarbituric Acid Spray Reagent for Deoxy Sugars and Sialic Acids  

Microsoft Academic Search

RECENTLY, new sensitive assays have been reported for deoxy sugars1, 2-keto,3-deoxy sugar acids2-4, and sialic acids5,6. In these assays, the products of periodate oxidation, malonaldehyde from deoxy sugars and beta-formylpyruvic acid from the latter two groups of compounds, are coupled with 2-thiobarbituric acid to produce a bright red chromophore. I wish to report an adaptation of these methods for spraying

Leonard Warren

1960-01-01

281

Preterm infant formula supplementation with ? linolenic acid and docosahexaenoic acid  

Microsoft Academic Search

Objectives: To investigate if supplementation of preterm infant formula with a high docosahexaenoic acid\\/eicosapentaenoic acid (DHA\\/EPA) ratio together with ?-linolenic acid (ALA) was able to maintain plasma and red blood cell DHA levels similar to that obtained with breast milk feeding without altering n-6 fatty acid status.Design and subjects: Preterm infants of mothers who elected not to breast feed (n=13)

A Rodriguez; D Raederstorff; P Sarda; C Lauret; F Mendy; B Descomps

2003-01-01

282

Carboxylic Acid Unknowns and Titration 90 CARBOXYLIC ACID UNKNOWN  

E-print Network

Carboxylic Acid Unknowns and Titration 90 CARBOXYLIC ACID UNKNOWN A. Solubility Tests: Water, NaHCO3, and NaOH Test the solubility of your acid first in neutral water, in NaOH/H2O, and in NaHCO3 to 30 drops. Swirl/mix well. Use of small stir bar helps. · Water Test: Only acids with small numbers

Jasperse, Craig P.

283

Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells  

PubMed Central

Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase) has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-?-boswellic acids (AKBA), a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health. PMID:19951413

2009-01-01

284

Acid Earth--The Global Threat of Acid Pollution.  

ERIC Educational Resources Information Center

Acid pollution is a major international problem, but the debate it has elicited has often clouded the distinction between myth and facts. This publication attempts to concerning the acid pollution situation. This publication attempts to identify available facts. It is the first global review of the problem of acid pollution and the first to…

McCormick, John

285

Focus Sheet | Hydrofluoric Acid Health hazards of hydrofluoric acid  

E-print Network

characterized by weight loss, brittle bones, anemia, and general ill health. Safe use If possible, avoid workingFocus Sheet | Hydrofluoric Acid Health hazards of hydrofluoric acid Hydrofluoric acid (HF bone. Skin exposure to highly concentrated HF (48% or greater) immediately results in serious

Wilcock, William

286

Acid placement and coverage in the acid jetting process  

E-print Network

Many open-hole acid treatments are being conducted by pumping acid through jetting ports placed at the end of coiled tubing or drill pipe. The filter-cake on the bore-hole is broken by the jet; the acid-soluble material is dissolved, creating...

Mikhailov, Miroslav I.

2009-05-15

287

Autohydrolysis of phytic acid.  

PubMed

The autohydrolysis of phytic acid at 120 degrees C resulted in the formation of most of the phosphate esters of myo-inositol in varying amounts depending upon the reaction time. Eighteen of the 39 chromatographically distinct myo-inositol mono-, bis-, tris-, tetrakis-, pentakis-, and hexakisphosphates have been characterized using two different HPLC systems. These myo-inositol phosphates were partially purified by preparative anion-exchange chromatography under acidic and alkaline elution conditions. The combination of these two methods provides a two-tiered chromatographic approach to the rapid and sensitive identification of inositol phosphates in complex mixtures. Identification of the products was confirmed by 1D and 2D (1)H NMR analysis. The analytical procedure was applied to the autohydrolysis of the mixture of inositol phosphates from corn steep water. PMID:10469496

Hull, S R; Gray, J S; Montgomery, R

1999-09-10

288

Acid hydrolysis of cellulose  

SciTech Connect

One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

Salazar, H.

1980-12-01

289

(Radioiodinated free fatty acids)  

SciTech Connect

The traveler participated in the Second International Workshop on Radioiodinated Free Fatty Acids in Amsterdam, The Netherlands where he presented an invited paper describing the pioneering work at the Oak Ridge National Laboratory (ORNL) involving the design, development and testing of new radioiodinated methyl-branched fatty acids for evaluation of heart disease. He also chaired a technical session on the testing of new agents in various in vitro and in vivo systems. He also visited the Institute for Clinical and Experimental Nuclear Medicine in Bonn, West Germany, to review, discuss, plan and coordinate collaborative investigations with that institution. In addition, he visited the Cyclotron Research Center in Liege, Belgium, to discuss continuing collaborative studies with the Osmium-191/Iridium-191m radionuclide generator system, and to complete manuscripts and plan future studies.

Knapp, Jr., F. F.

1987-12-11

290

The utilization of tricarboxylic acid cycle acids and the uptake of succinic acid by Neurospora crassa  

E-print Network

, Clavice s u urea and several species of ~dtlt . 1' ~ d 9' p ~ d t 1966 (69) th t ~C. PRL 1980 was able to grow with succinic acid as the sole carbon source in an acidic medium. The efficiency of total biomass synthesis on succinic acid was considerably..., Clavice s u urea and several species of ~dtlt . 1' ~ d 9' p ~ d t 1966 (69) th t ~C. PRL 1980 was able to grow with succinic acid as the sole carbon source in an acidic medium. The efficiency of total biomass synthesis on succinic acid was considerably...

Gilliland, Patti Lynn

2012-06-07

291

Molecular Structure of Sulfuric Acid  

NSDL National Science Digital Library

H2SO4 was discovered by alchemists and made from heating a compound of iron sulfate. In 1740, sulfuric acid was produced for commercial sale. Sulfuric acid is a very strong acid which is used in car batteries. The acid disassociates in water to give two protons and sulfate. This acid can destroy flesh and cause blindness. It was discovered in the 19th century that adding sulfuric acid to soil produces phosphorus, which is beneficial to plants; hence, sulfuric acid is used as a fertilizer in the form of super phosphate and ammonium sulfate. Sulfuric acid is also used to refine petroleum and process metals, and is found in paints and car batteries.

2002-08-15

292

Molecular Structure of Maleic acid  

NSDL National Science Digital Library

Maleic acid is colorless to white crystals with a faint acidulous odor and a characteristic repulsive, astringent taste. Maleic acid is used in making polyesters, surface coatings, lubricant additives, agricultural chemicals and paint vehicles. It is used in organic synthesis of fumaric acid, succinic, aspartic, tartaric, propionic, lactic, malonic, acrylic and hydrocarylic acids. Maleic acid and its anhydride are prepared industrially by the catalytic oxidation of benzene. Maleic acid may be released into waste water during its production and used in the manufacture of polymer products. Dust of maleic acid is irritating to the eyes, nose and throat. The general population is exposed to maleic acid in areas with heavy traffic since it is found in aerosols from auto exhaust.

2004-11-10

293

Crosslinked acid gels offer advantages  

SciTech Connect

Acid polymer gels having a pH less than one have been crosslinked for retarding the chemical and physical activity of hydrochloric acid on calcareous formations. Hydrochloric acid concentrations from /one quarter/% to 28% have been successfully crosslinked. This unique stimulation fluid offers high viscosity with adequate shear stability, perfect support for propants, and clay stabilization. Additionally, the fluid provided effective fluid loss control and retardation of acid reaction enabling live acid to penetrate deeper into the formation for better conductivity; furthermore, there is practically a residue free break for rapid cleanup of the well after the job. Results of lab and field tests show this new acid crosslinked system to be an effective stimulation fluid for acidizing and acid fracturing in calcareous and sandstone formations having low permeability. 5 refs.

Pabley, A.S.; Holcomb, D.L.

1981-09-28

294

Molecular Structure of Glutaric acid  

NSDL National Science Digital Library

Glutaric acid is a colorless liquid and white crystals as a solid occurring in plants and animal tissues. It is used in organic synthesis and as an intermediate for the manufacture of polymers such as polyamides and polyesters, ester plasticizers and corrosion inhibitors. It is also useful in the application of decreasing polymer elasticity and in a variety of industrial applications. In addition glutaric acid plays an important role as an intermediary in the Krebs cycle and is used in medication against a large number of viruses and in animal diabetes. Glutaric acid can be prepared from cyclopentanone by oxidative ring fission with nitric acid and in the presence of a catalyst. Glutaric acid has the lowest melting point among dicarboxylic acids (98 C); it is very soluble in water and the solution in water is a medium strong acid. Short-term exposure to glutaric acid may cause irritation to the eyes, skin and the respiratory tract.

2004-11-10

295

Acid hydrolysis of chitosans  

Microsoft Academic Search

The hydrolysis of the O-glycosidic linkages (depolymerization) and the N-acetyl linkage (de-N-acetylation) of partially N-acetylated chitosans were studied in dilute and concentrated HCl. The rate of hydrolysis of the glycosidic linkages was found to be equal to the rate of de-N-acetylation in dilute acid, while the glycosidic linkages was hydrolysed more than 10 times faster than the N-acetyl linkage in

K. M. Vårum; M. H. Ottøy; O. Smidsrød

2001-01-01

296

Acid rain in Asia  

Microsoft Academic Search

Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to\\u000a the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging\\u000a perception that the problem in these Western nations is nearing solution. The situation in

Neeloo Bhatti; David G. Streets; Wesley K. Foell

1992-01-01

297

Lipoic acid biosynthesis defects.  

PubMed

Lipoate is a covalently bound cofactor essential for five redox reactions in humans: in four 2-oxoacid dehydrogenases and the glycine cleavage system (GCS). Two enzymes are from the energy metabolism, ?-ketoglutarate dehydrogenase and pyruvate dehydrogenase; and three are from the amino acid metabolism, branched-chain ketoacid dehydrogenase, 2-oxoadipate dehydrogenase, and the GCS. All these enzymes consist of multiple subunits and share a similar architecture. Lipoate synthesis in mitochondria involves mitochondrial fatty acid synthesis up to octanoyl-acyl-carrier protein; and three lipoate-specific steps, including octanoic acid transfer to glycine cleavage H protein by lipoyl(octanoyl) transferase 2 (putative) (LIPT2), lipoate synthesis by lipoic acid synthetase (LIAS), and lipoate transfer by lipoyltransferase 1 (LIPT1), which is necessary to lipoylate the E2 subunits of the 2-oxoacid dehydrogenases. The reduced form dihydrolipoate is reactivated by dihydrolipoyl dehydrogenase (DLD). Mutations in LIAS have been identified that result in a variant form of nonketotic hyperglycinemia with early-onset convulsions combined with a defect in mitochondrial energy metabolism with encephalopathy and cardiomyopathy. LIPT1 deficiency spares the GCS, and resulted in a combined 2-oxoacid dehydrogenase deficiency and early death in one patient and in a less severely affected individual with a Leigh-like phenotype. As LIAS is an iron-sulphur-cluster-dependent enzyme, a number of recently identified defects in mitochondrial iron-sulphur cluster synthesis, including NFU1, BOLA3, IBA57, GLRX5 presented with deficiency of LIAS and a LIAS-like phenotype. As in DLD deficiency, a broader clinical spectrum can be anticipated for lipoate synthesis defects depending on which of the affected enzymes is most rate limiting. PMID:24777537

Mayr, Johannes A; Feichtinger, René G; Tort, Frederic; Ribes, Antonia; Sperl, Wolfgang

2014-07-01

298

Acid Deposition Sampling  

NSDL National Science Digital Library

This learning activity from the Advanced Technology Environmental and Energy Center (ATEEC) provides students with the opportunity to use analytical meters and instruments and perform acid deposition sampling. Students will collect samples from various sources over a period of time, then measure pH and develop graphs or charts. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

Willey, Babe

2011-02-17

299

Modulation of membrane curvature by phosphatidic acid and lysophosphatidic acid.  

PubMed

The local generation of phosphatidic acid plays a key role in the regulation of intracellular membrane transport through mechanisms which are largely unknown. Phosphatidic acid may recruit and activate downstream effectors, or change the biophysical properties of the membrane and directly induce membrane bending and/or destabilization. To evaluate these possibilities, we determined the phase properties of phosphatidic acid and lysophosphatidic acid at physiological conditions of pH and ion concentrations. In single-lipid systems, unsaturated phosphatidic acid behaved as a cylindrical, bilayer-preferring lipid at cytosolic conditions (37 degrees C, pH 7.2, 0.5 mM free Mg2+), but acquired a type-II shape at typical intra-Golgi conditions, a mildly acidic pH and submillimolar free Ca2+ (pH 6.6-5.9, 0.3 mM Ca2+). Lysophosphatidic acid formed type-I lipid micelles in the absence of divalent cations, but anhydrous cation-lysophosphatidic acid bilayer complexes in their presence. These data suggest a similar molecular shape for phosphatidic acid and lysophosphatidic acid at cytosolic conditions; however, experiments in mixed-lipid systems indicate that their shape is not identical. Lysophosphatidic acid stabilized the bilayer phase of unsaturated phosphatidylethanolamine, while the opposite effect was observed in the presence of phosphatidic acid. These results support the hypothesis that a conversion of lysophosphatidic acid into phosphatidic acid by endophilin or BARS (50 kDa brefeldin A ribosylated substrate) may induce negative spontaneous monolayer curvature and regulate endocytic and Golgi membrane fission. Alternative models for the regulation of membrane fission based on the strong dependence of the molecular shape of (lyso)phosphatidic acid on pH and divalent cations are also discussed. PMID:12656989

Kooijman, Edgar E; Chupin, Vladimir; de Kruijff, Ben; Burger, Koert N J

2003-03-01

300

Exposures to acidic aerosols  

SciTech Connect

Ambient monitoring of acid aerosols in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. Measurements made in Kingston, TN, and Steubenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m/sup 3/ more than 10 times during summer months. Periods of elevated acidic aerosols occur less frequently in winter months. The H+ determined during episodic conditions in southern Ontario indicates that respiratory tract deposition can exceed the effects level reported in clinical studies. Observed 12-hr H+ concentrations exceeded 550 nmole/m/sup 3/ (approximately 27 micrograms/m/sup 3/ H/sub 2/SO/sub 4/). The maximum estimated 1-hr concentration exceeded 1500 nmole/m/sup 3/ for H+ ions. At these concentrations, an active child might receive more than 2000 nmole of H+ ion in 12 hr and in excess of 900 nmole during the hour when H/sub 2/SO/sub 4/ exceeded 50 micrograms/m/sup 3/.

Spengler, J.D.; Keeler, G.J.; Koutrakis, P.; Ryan, P.B.; Raizenne, M.; Franklin, C.A.

1989-02-01

301

Exposures to acidic aerosols  

SciTech Connect

Ambient monitoring of acid aerosols in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. Measurements made in Kingston, TN, and Steubenville, OH, resulted in 24-hr H(+) ion concentrations exceeding 100 nmole/cu m more than 10 times during summer months. Periods of elevated acidic aerosols occur less frequently in winter months. The H(+) determined during episodic conditions in southern Ontario indicates that respiratory tract deposition can exceed the effects level reported in clinical studies. Observed 12-hr (H+) concentrations exceeded 550 nmole/cu m (approximately 27 microgram/cu m H{sub 2}SO{sub 4}). The maximum estimated 1-hr concentration exceeded 1500 nmole/cu m for H(+) ions. At these concentrations, an active child might receive more than 2000 nmole of H(+) ion in 12 hr and in excess of 900 nmole during the hour when H{sub 2}SO{sub 4} exceeded 50 microgram/cu m.

Spengler, J.D.; Keeler, G.J.; Koutrakis, P.; Ryan, P.B.; Raizenne, M.

1989-01-01

302

Grading acid rain research  

NASA Astrophysics Data System (ADS)

The growing concern with the environmental effects of acid rain has spawned a number of study groups in recent years, and now the Office of Science and Technology Policy (OSTP) has released what is essentially a study of a study. In January 1982, White House Science Advisor George Keyworth asked William Nierenberg, Director of the Scripps Institution of Oceanography, and a panel of nine scientists to conduct a peer review of three separate reports on acid deposition in eastern North America that had been turned in by U.S.-Canadian scientific working groups.Those studies had been requisitioned by a 1980 Memorandum of Intent between the United States and Canada regarding transboundary air pollution. Overall, the Nierenberg peer review panel was “impressed with the efforts of the United States-Canadian Working Groups,” (labeled Groups 1, 2, and 3B), but it also found problems. While applauding the work groups' exhaustive search through the acid rain literature, the Nierenberg panel cited what they call an “overdependence on ‘soft’ literature,” or writings such as in-house reports and personal communications, which are outside the publicly available (and carefully scrutinized) body of scientific literature.

303

Microbial naphthenic Acid degradation.  

PubMed

Naphthenic acids (NAs) are an important group of trace organic pollutants predominantly comprising saturated aliphatic and alicyclic carboxylic acids. NAs are ubiquitous; occurring naturally in hydrocarbon deposits (petroleum, oil sands, bitumen, and crude oils) and also have widespread industrial uses. Consequently, NAs can enter the environment from both natural and anthropogenic processes. NAs are highly toxic, recalcitrant compounds that persist in the environment for many years, and it is important to develop efficient bioremediation strategies to decrease both their abundance and toxicity in the environment. However, the diversity of microbial communities involved in NA-degradation, and the mechanisms by which NAs are biodegraded, are poorly understood. This lack of knowledge is mainly due to the difficulties in identifying and purifying individual carboxylic acid compounds from complex NA mixtures found in the environment, for microbial biodegradation studies. This paper will present an overview of NAs, their origin and fate in the environment, and their toxicity to the biota. The review describes the microbial degradation of both naturally occurring and chemically synthesized NAs. Proposed pathways for aerobic NA biodegradation, factors affecting NA biodegradation rates, and possible bioremediation strategies are also discussed. PMID:20359455

Whitby, Corinne

2010-01-01

304

Acid rain: Reign of controversy  

SciTech Connect

Acid Rain is a primer on the science and politics of acid rain. Several introductory chapters describe in simple terms the relevant principles of water chemistry, soil chemistry, and plant physiology and discuss the demonstrated or postulated effects of acid rain on fresh waters and forests as well as on statuary and other exposed objects. There follow discussions on the economic and social implications of acid rain (for example, possible health effects) and on the sources, transport, and distribution of air pollutants.

Kahan, A.M.

1986-01-01

305

Enviropedia: Introduction to Acid Rain  

NSDL National Science Digital Library

This resource provides information about acid rain, a widespread term used to describe all forms of acid precipitation. The sources, nature, and chemistry of acid rain are discussed, along with its impact on buildings, soils, freshwater lakes, trees, and wildlife. Other topics include measuring, modeling, and monitoring acid rain; and vehicle and industrial emission controls. The problem of airborne pollutants migrating across international borders is also discussed.

306

Antioxidant properties of nitrocaffeic acids  

Microsoft Academic Search

A series of nitrodihydroxybenzenes and nitrocaffeic acids were prepared and their hydroxyl radical (OH°) and superoxide anion (O2?) scavenging activities and xanthine oxidase inhibition activities were evaluated. 2-Nitrocaffeic acid is the more potent O2? scavenger. 2- (and 5)-Nitrocaffeic acids are the more potent xanthine oxidase inhibitors.

Jean-Luc Grenier; Nicole Cotelle; Philippe Cotelle; Jean-Pierre Catteau

1996-01-01

307

Acid rain and dry deposition  

Microsoft Academic Search

This book provides information on the formation of acid rain and the long-range transport of air pollutants. The effects of acid precipitation on both terrestrial and aquatic ecosystems are highlighted and technical and policy issues associated with the delineation and implementation of control strategies for acid rain and dry deposition are covered. Dry deposition is addressed, with emphasis given to

Canter

1985-01-01

308

Acid rain: the international response  

Microsoft Academic Search

Acid rain or technically “acid deposition” has far reaching environmental, economic, political and international implications. It has been blamed for large?scale damage to aquatic ecosystems and forests in Scandinavia, southeastern Canada and the northeastern United States. A number of other countries have expressed concern about the possible affects of acid rain on water bodies, forests, agricultural crops and material structures.Never

Gordon L. Brady; Joseph C. Selle

1985-01-01

309

Carboxylic acid sorption regeneration process  

DOEpatents

Carboxylic acids are sorbed from aqueous feedstocks into an organic liquid phase or onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with aqueous alkylamine thus forming an alkylammonium carboxylate which is dewatered and decomposed to the desired carboxylic acid and the alkylamine.

King, C. Judson (Kensington, CA); Poole, Loree J. (Baton Rouge, LA)

1995-01-01

310

Do We Need Gastric Acid?  

Microsoft Academic Search

Evidence from comparative anatomy and physiology studies indicates that gastric acid secretion developed during the evolution of vertebrates approximately 350 million years ago. The cellular mechanisms that produce gastric acid have been conserved over the millennia and therefore proton pump inhibitors have pharmacological effects in almost all relevant species. These observations suggest that gastric acid provides an important selective advantage;

D. Pohl; M. Fox; M. Fried; B. Göke; C. Prinz; H. Mönnikes; G. Rogler; M. Dauer; J. Keller; F. Lippl; I. Schiefke; U. Seidler; H. D. Allescher

2008-01-01

311

Carboxylic acid sorption regeneration process  

DOEpatents

Carboxylic acids are sorbed from aqueous feedstocks into an organic liquid phase or onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with aqueous alkylamine thus forming an alkylammonium carboxylate which is dewatered and decomposed to the desired carboxylic acid and the alkylamine. 10 figs.

King, C.J.; Poole, L.J.

1995-05-02

312

Practical synthesis of a chromene analog for use as a retinoic acid receptor alpha antagonist lead compound  

PubMed Central

Retinoic acid receptor alpha (RAR?) selective compounds may guide the design of drugs that can be used in conjunction with hormonal adjuvant therapy in the treatment of breast cancer. Herein we report a modified synthesis of a known RAR? antagonist, 2-fluoro-4-[[[8-bromo-2,2-dimethyl-4-(4-methylphenyl)chroman-6-yl]carbonyl]amino]benzoic acid and a synthesis of its unknown, desfluoro analog, 4-[[[8-bromo-2,2-dimethyl-4-(4-methylphenyl)chroman-6-yl]carbonyl]amino]benzoic acid. The modified route allows for facile reaction workups, increased yields, lower cost and incorporates a green alternative step. Structure–activity relationship studies determined through functional cell-based assays, demonstrated antagonism to RAR? for both compounds. Molecular modeling within the RAR? binding pocket was used to compare binding interactions of the desfluoro analog to a known RAR antagonist. PMID:23474897

Jetson, Rachael; Malik, Neha; Luniwal, Amarjit; Chari, Venkatesh; Ratnam, Manohar; Erhardt, Paul

2013-01-01

313

Development of HPLC method by UV-VIS detection for the quantification of phenolic acids in different Ocimum sanctum Linn. extracts.  

PubMed

A simple and rapid chromatographic method has been developed for the simultaneous determination of five phenolic acids including Gallic acid, Chloroganic acid, Syringic acid, Benzoic acid and Vanillic acid by HPLC with UV-VIS detector. These Phenolic acids were separated by analytical column Intersil ODS-3 C18, a gradient elution system of ACN and acidified water solution with 1ml/min flow rate and quantified in a total run of 30 minutes at 210nm wavelength. In the quantitative analysis of these compounds showed good regression (0.995-0.999). The limit of detection [LOD] and limit of quantification [LOQ] of these compounds were in the range of 0.15-0.46 and 0.42-2.47 ?g/mL. The average recoveries were between 95.8-103.1% and their RSD values were less than 3.34%. By the proposed method Gallic acid, Chloroganic acid and Syringic acid were found and quantified in Methanolic, Ethanolic and Acetonic extract of Ocimum sanctum Linn. leaves. While the two other phenolic acids benzoic acid and vanillic acid was not found in the extracts of Ocimum sanctum Linn. leaves. PMID:25176382

Shafqatullah; Khan, Rasool; Hassan, Waseem; Hussain, Arshad; Asadullah; Rehman, Khaliqur; Ali, Javid

2014-09-01

314

Probing acid-amide intermolecular hydrogen bonding by NMR spectroscopy and DFT calculations  

NASA Astrophysics Data System (ADS)

Benzene carboxylic acids and benzamide act as their self-complement in molecular recognition to form inter-molecular hydrogen bonded dimers between amide and carboxylic acid groups, which have been investigated by 1H, 13C and 15N NMR spectroscopy. Extensive NMR studies using diffusion ordered spectroscopy (DOSY), variable temperature 1D, 2D NMR, established the formation of heterodimers of benzamide with benzoic acid, salicylic acid and phenyl acetic acid in deuterated chloroform solution. Association constants for the complex formation in the solution state have been determined. The results are ascertained by X-ray diffraction in the solid state. Intermolecular interactions in solution and in solid state were found to be similar. The structural parameters obtained by X-ray diffraction studies are compared with those obtained by DFT calculations.

Chaudhari, Sachin Rama; Suryaprakash, N.

2012-05-01

315

Determination of the solubility products of nitrilotriacetic acid, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid  

Microsoft Academic Search

A method is described for the determination of solubility products for polyaminopolycarboxylic acids. The neutral protonated species of NTA (nitrilotriacetic acid), EDTA (ethylenediaminetetraacetic acid) and DTPA (diethylenetriaminepentaacetic acid) were precipitated at low pH values. The amount of precipitate was quantified by gravimetry and complexometric titrations with a standard zinc(II) solution. The following solubility products were obtained: SH3NTA=10?16.36, SH4EDTA=10?24.66 and SH5DTPA=10?30.43.

Jouni Karhu; Leo Harju; Ari Ivaska

1999-01-01

316

Intramolecular deactivation processes in complexes of salicylic acid or glycolic acid with Eu(III)  

NASA Astrophysics Data System (ADS)

The complexation of Eu(III) by 2-hydroxy benzoic acid (2HB) or glycolic acid (GL) was investigated using steady-state and time-resolved laser spectroscopy. Experiments were carried out in H 2O as well as in D 2O in the temperature range of 80K

Kuke, S.; Marmodée, B.; Eidner, S.; Schilde, U.; Kumke, M. U.

2010-04-01

317

Comparing organic acids and salt derivatives as antimicrobials against selected poultry-borne Listeria monocytogenes strains in vitro.  

PubMed

This article reports on the antilisterial properties of selected organic acids and salt derivatives in order to suggest possible alternatives in food preservation and pathogen control in the poultry meat processing industry. The susceptibility of two Listeria monocytogenes isolates was assessed against five organic acids (lactic, acetic, malic, citric, and propionic) and two acid-salt derivatives (sorbic acid [potassium salt] and benzoic acid [sodium salt]) across a series of pH environments. Minimum inhibitory concentrations (MICs) of the acids were tested against the two strains by means of an agar-dilution method. In general, strain CC60 was found to be more resistant than strain CC77 to both organic acids and salts. At pH values of 7 and above, high MIC levels (low susceptibility) were noted for potassium sorbate, sodium benzoate, and lactic acids, whereas susceptibility at lower pH increased reaching pH5 where the isolates were susceptible to all the organic acids tested. A small increase in pH notably reduced antimicrobial activity against the organisms. At pH 7, the isolates just about lost susceptibility to benzoic, lactic, malic, and sorbic acids. Although the activity of the majority of acids was linked to pH, some acids were not as closely related (e.g., potassium sorbate, sodium benzoate, and citric acid), and this suggests that the type of organic acids plays a role in inhibition. The relatively high MICs reported for compounds that are conventionally used as preservatives against Listeria spp. raise concern. The results furthermore suggest that the type of organic acid used to set pH, and not only pH alone, plays a role in determining inhibition. It was confirmed that a "one size fits all" approach to preservation is not always effective. Furthermore, the need for microbiological data to the subspecies level to inform the selection of preservatives was highlighted. PMID:23190165

Lues, Jan Frederick Rykers; Theron, Maria Magdalena

2012-12-01

318

Solvent extraction of inorganic acids  

E-print Network

and solubility of nitric acid and sulfuric acid with organic solvents have been published Olander, Donadieu, and Benedict (12) studied the 'istributlon of nitric acid between water and tributyl phosphate-hexane solvent nd dcharf and Gean. . oplis (1...(. ) reported on the system nit ic acid-water-n-butyl alcohols Distribution of sulfuric acid was m-de oy Bchlea and Gean- koplis (19) with n-butyl alcohol, by Gibby ( 7) with nitro- benzene and by Peakin (14) with pyri 'in~. Baldwin, Biggies an" Soldano (2...

Ysrael, Miguel Curie

2012-06-07

319

The politics of acid rain  

SciTech Connect

This work examines and compares the acid rain policies through the different political systems of Canada, Great Britain and the United States. Because the flow of acid rain can transcend national boundaries, acid rain has become a crucial international problem. According to the author, because of differences in governmental institutions and structure, the extent of governmental intervention in the industrial economy, the degree of reliance on coal for power generation, and the extent of acid rain damage, national responses to the acid rain problem have varied.

Wilcher, M.E. (Pennsylvania State Univ., New Kensington, PA (US))

1989-01-01

320

Tested Demonstrations: Color Oscillations in the Formic Acid-Nitric Acid-Sulfuric Acid System.  

ERIC Educational Resources Information Center

Presented are procedures for demonstrating the production of color oscillations when nitric acid is added to a formic acid/concentrated sulfuric acid mixture. Because of safety considerations, "Super-8" home movie of the color changes was found to be satisfactory for demonstration purposes. (JN)

Raw, C. J. G.; And Others

1983-01-01

321

Amino acids in Arctic aerosols  

NASA Astrophysics Data System (ADS)

Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs) in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS) to analyze 20 amino acids to quantify compounds at fmol m-3 levels. Mean total FAA concentration was 1070 fmol m-3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45-60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m-3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (<0.49 ?m) and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanics.

Scalabrin, E.; Zangrando, R.; Barbaro, E.; Kehrwald, N. M.; Gabrieli, J.; Barbante, C.; Gambaro, A.

2012-07-01

322

Amino acids in Arctic aerosols  

NASA Astrophysics Data System (ADS)

Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs) in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS) to analyze 20 amino acids and quantify compounds at fmol m-3 levels. Mean total FAA concentration was 1070 fmol m-3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45-60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m-3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (< 0.49 ?m) and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanic emissions.

Scalabrin, E.; Zangrando, R.; Barbaro, E.; Kehrwald, N. M.; Gabrieli, J.; Barbante, C.; Gambaro, A.

2012-11-01

323

Molecular Structure of Picric acid  

NSDL National Science Digital Library

Picric Acid was first discovered in 1771 by a British Chemist named Peter Woulfe by treatment of indigo with nitric acid. It is most commonly seen in its yellow, water-soluble, crystalline form. For this reason, picric acid first saw use as a dyeing agent in textiles. However, around 1849 it was discovered (for obvious reasons) that picric acid is a shock, heat, and friction-sensitive explosive. Its first use as an explosive material came in military weaponry: torpedoes in particular due to its shock-sensitive nature not requiring a detonator to explode on contact with a target. However, picric acid was found to be highly corrosive to metals, making the weapons very difficult to handle and the acid itself difficult to store. Today, picric acid is used more widely as an ingredient in the manufacture of inert dyes and stable explosives such as dynamite.

2002-09-23

324

Molecular Structure of Sorbic acid  

NSDL National Science Digital Library

Sorbic acid is a colorless or white crystalline powder, with a weak characteristic odor and slightly acidic taste. It may be obtained from berries of the mountain ash or prepared synthetically by condensing crotonaldehyde and malonic acid in pyridine solution. Sorbic acid is a polyunsaturated fat used to inhibit molds and yeast, is a fungistatic agent for foods (especially cheeses, wine and baked goods). The main use of sorbic acid is as a preservative in foods, animal feeds, tobacco, cosmetics and pharmaceuticals, as well in packing materials for these substances and in other products that come in contact with human or animal skin in some way. Sorbic acid is also used as an intermediate for plasticizers and lubricants. Sorbic acid reacts with potassium to make potassium sorbate and with calcium to make calcium sorbate.

2004-11-11

325

Corals on Acid  

NSDL National Science Digital Library

The objective of this inquiry-based lesson is for learners to gain an understanding of how increasing ocean acidity can affect the calcification of marine organisms. During this activity, learners: (1) design an experiment to quantify the CaCO3 concentration of two invertebrate skeletal samples, one that has been soaked in normal seawater and another in a low pH solution, and (2) use critical thinking and discussion to evaluate possible explanations for the difference in the skeletal CaCO3 compositions. This lesson plan includes a post-activity demonstration, which shows how the dissolution of CO2 into the ocean lowers pH.

Boleman, Casey L.; Gravinese, Philip M.; Muse, Ellen N.; Marston, Andrea E.; Windsor, John G.

2013-01-01

326

Microbial hyaluronic acid production.  

PubMed

Hyaluronic acid (HA) is a commercially valuable medical biopolymer increasingly produced through microbial fermentation. Viscosity limits product yield and the focus of research and development has been on improving the key quality parameters, purity and molecular weight. Traditional strain and process optimisation has yielded significant improvements, but appears to have reached a limit. Metabolic engineering is providing new opportunities and HA produced in a heterologous host is about to enter the market. In order to realise the full potential of metabolic engineering, however, greater understanding of the mechanisms underlying chain termination is required. PMID:15599518

Chong, Barrie Fong; Blank, Lars M; Mclaughlin, Richard; Nielsen, Lars K

2005-01-01

327

Action of picolinic acid and structurally related pyridine carboxylic acids on quinolinic acid-induced cortical cholinergic damage  

Microsoft Academic Search

Picolinic acid, a pyridine monocarboxylic acid derived from tryptophan metabolism by the kynurenine pathway, was shown to block cortical cholinergic neurotoxicity induced by quinolinic acid (QUIN), a pyridine dicarboxylic acid yielded by the same pathway. This study examined the specificity of the anti-toxic effect of picolinic acid by comparing its effect with several structurally related mono- and dicarboxylic acids, and

J. Cockhill; K. Jhamandas; R. J. Boegman; R. J. Beninger

1992-01-01

328

(E)-4-{[(Pyridin-4-yl-methyl-idene)amino]-meth-yl}benzoic acid  

PubMed Central

The title mol­ecule, C14H12N2O2, exhibits a V-shaped conformation with a dihedral angle of 59.69?(3)° between the benzene and pyridine rings. In the crystal, O—H?N hydrogen bonds link the mol­ecules into zigzag chains along [010]. PMID:22346932

Han, Sun Hwa; Lee, Soon W.

2012-01-01

329

ACUTE TOXICITY OF SELECTED SUBSTITUTED PHENOLS, BENZENES AND BENZOIC ACID ESTERS TO FATHEAD MINNOWS 'PIMEPHALES PROMELAS'  

EPA Science Inventory

Flow-through acute toxicity tests were conducted with 24 organic compounds using fathead minnows Pimephales promelas as test organisms. The tested toxicants consisted of 11 substituted phenols, four substituted benzenes and nine esters. The 96-h LC50 values determined for these c...

330

INFLUENCE OF ALTERNATIVE ELECTRON ACCEPTORS ON THE ANAEROBIC BIODEGRADABILITY OF CHLORINATED PHENOLS AND BENZOIC ACIDS  

EPA Science Inventory

Nitrate, sulfate, and carbonate were used as electron acceptors to examine the anaerobic biodegradability of chlorinated aromatic compounds in estuarine and freshwater sediments. he respective denitrifying, sulfidogenic, and methanogenic enrichment cultures were established on ea...

331

Progress in Organic Coatings 56 (2006) 135145 Incorporation of benzoic acid and sodium benzoate into  

E-print Network

as compared to currently used biocides in marine biofouling protection, were incorporated into silicone biofouling is the accumulation and growth of marine organisms on surfaces of structures immersed in natural water [1,2]. Biofouling causes serious problems to the marine industry [3]. The layer of attached

Al-Juhani, Abdulhadi A.

332

Variations on a theme: synthesis and modification of plant benzoic acids  

E-print Network

benzoate (MeBA) and methyl salicylate (MeSA) are present in the floral scents of more than 100 species are synthesized both directly from shikimate/chorismate and from phenylalanine in plants; however, few genes methylation, glucosylation, or activation with Coenzyme A. As these modifications alter the stability

Wildermuth, Mary C

333

Quantitative temperature effects in the reactions of diphenyldiazomethanes with benzoic acids in toluene  

E-print Network

in 09 vas rooordod at tiao4 intorvalsi Xn the an)ority of tho runs~ the 09 readings were takes ?atil the final. roa4iag was appresisately ono eighth tho original val~e whish oorreeponds to throe half Uves of the diphoaqldianosothaao deoaapositioai Xa... in 09 vas rooordod at tiao4 intorvalsi Xn the an)ority of tho runs~ the 09 readings were takes ?atil the final. roa4iag was appresisately ono eighth tho original val~e whish oorreeponds to throe half Uves of the diphoaqldianosothaao deoaapositioai Xa...

Foldvary, Elmer

2012-06-07

334

Nucleic Acid Detection Methods  

DOEpatents

The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3'-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated.

Smith, Cassandra L. (Boston, MA); Yaar, Ron (Brookline, MA); Szafranski, Przemyslaw (Boston, MA); Cantor, Charles R. (Boston, MA)

1998-05-19

335

Nucleic acid detection methods  

DOEpatents

The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3{prime}-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated. 18 figs.

Smith, C.L.; Yaar, R.; Szafranski, P.; Cantor, C.R.

1998-05-19

336

DOI: 10.1002/cssc.201000111 A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated  

E-print Network

,*[b] and Robert G. Bergman*[a] Today's chemical industry is highly dependent on crude oil as a feedstock the experimental procedure previously reported for the synthesis of allyl alcohol from glycerol,[4] by heating

337

Growth of nitric acid hydrates on thin sulfuric acid films  

NASA Technical Reports Server (NTRS)

Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

1994-01-01

338

Local and Systemic Biosynthesis of Salicylic Acid in Infected Cucumber Plants.  

PubMed Central

Radiolabeling studies showed that salicylic acid (SA), an essential component in the signal transduction pathway leading to systemic acquired resistance, is synthesized from phenylalanine (Phe) and benzoic acid in cucumber (Cucumis sativus L.) plants inoculated with pathogens. Leaf discs from plants inoculated with either tobacco necrosis virus or Pseudomonas lachrymans incorporated more [14C]Phe into [14C]SA than mock-inoculated controls. The identity of SA was confirmed by gas chromatography-mass spectrometry. No reduction in specific activity of [14C]SA was observed for either free or bound SA between control and infected plants after feeding [14C]Phe. A specific inhibitor of Phe ammonia-lyase, 2-aminoindan-2-phosphonic acid, completely inhibited the incorporation of [14C]Phe into [14C]SA, although plants treated with 2-aminoindan-2-phosphonic acid could still produce [14C]SA from [14C]benzoic acid. Biosynthesis of SA in tissue inoculated with tobacco necrosis virus followed a transient pattern with the highest induction occurring 72 h postinoculation. Uninfected tissues from an infected plant synthesized de novo more SA than did controls. This suggests the involvement of a systemic signal triggering SA synthesis in tissue distant from the site of infection that display systemic acquired resistance. PMID:12228656

Meuwly, P.; Molders, W.; Buchala, A.; Metraux, J. P.

1995-01-01

339

Thermochemical studies on the quantity-antibacterial effect relationship of four organic acids from Radix Isatidis on Escherichia coli growth.  

PubMed

In this report, we have investigated the inhibitory action of four organic acids from Radix Isatidis on Escherichia coli growth was investigated at 37 degrees C by using a microcalorimeter. The four organic acids were: syringic acid, 2-amino-benzoic acid, salicylic acid, benzoic acid. In accordance with thermokinetic model, the pertaining relationships of the drugs, such as growth inhibitory ratio vs. concentration, maximal power-output vs. growth rate constant, growth rate constant vs. concentration, were obtained. Half-inhibitory concentration of the drugs, IC(50), was obtained by quantitative analysis. From the view of thermodynamics and molecular structure, the relationship between quantity and effect of the four organic acids has been discussed. The functional groups on phenyl ring had important influence on the antibacterial activities. Our work suggests that microcalorimetry is a fast, simple and more sensitive method that can be easily performed and applied to study the anti-bacterial activities of organic acids from Radix Isatidis on microorganism compared to other biological methods. PMID:18591764

Kong, Weijun; Zhao, Yanling; Shan, Limei; Xiao, Xiaohe; Guo, Weiying

2008-07-01

340

Sedimentation of sulfuric acid in acid tars from current production  

Microsoft Academic Search

Acid tars obtained in treating T-750, KhF-12, and I-8A oils were investigated for purposes of recovering sulfuric acid and asphalt binders from the compositions and of determining the effects of storage time on the recovery. The consumption and sedimentation levels of sulfuric acid during storage for different periods and at different temperatures were assessed. The characteristics of an asphalt binder

T. L. Denisova; A. F. Frolov; A. N. Aminov; S. P. Novosel'tsev

1987-01-01

341

[Modification of hyaluronic acid with aromatic amino acids].  

PubMed

Hyaluronic acid was modified with aromatic amino acids (5-aminosalicylic, 4-aminosalicylic, anthranilic, and p-aminobenzoic) in the presence of 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide. The modified glycans contained 9-43% of arylamide groups and 10-33% of isoureidocarbonyl groups depending on the nature of the amino acid. Reduction with sodium borohydride allowed the conversion of isoureidocarbonyl groups into hydroxymethyl groups. PMID:15787219

Ponedel'kina, I Iu; Odinokov, V N; Vakhrusheva, E S; Golikova, M T; Khalilov, L M; Dzhemilov, U M

2005-01-01

342

Conversion of phenolics to lignans: Sinapic acid to thomasidioic acid  

Microsoft Academic Search

Changes in sinapic acid when exposed to aqueous alkaline conditions were elucidated. Sinapic acid was exposed to a volatile\\u000a buffer (pH 8.5) for 24 h, lyophilized, acidified, extracted, and characterized using nuclear magnetic resonance and mass spectroscopy.\\u000a The product obtained was identified as the lignan thomasidioic acid. This identification was confirmed by comparison with\\u000a a synthesized authentic sample of thomasidioic

M. I. Rubino; S. D. Arntfield; J. L. Charlton

1995-01-01

343

Simultaneous determination of aromatic acid metabolites of styrene and styrene-oxide in rat urine by gas chromatography -flame ionisation detection  

E-print Network

1 Simultaneous determination of aromatic acid metabolites of styrene and styrene-oxide in rat urine metabolites of styrene and styrene-oxide in rat urine: i.e. benzoic (BA), phenylacetic (PAA), mandelic (MA to quantitatively analyze styrene, styrene-oxide, ethylbenzene and toluene metabolites in urines samples from rats

Paris-Sud XI, Université de

344

Quantitative Analysis of the Modes of Growth Inhibition by Weak Organic Acids in Saccharomyces cerevisiae  

PubMed Central

Weak organic acids are naturally occurring compounds that are commercially used as preservatives in the food and beverage industries. They extend the shelf life of food products by inhibiting microbial growth. There are a number of theories that explain the antifungal properties of these weak acids, but the exact mechanism is still unknown. We set out to quantitatively determine the contributions of various mechanisms of antifungal activity of these weak acids, as well as the mechanisms that yeast uses to counteract their effects. We analyzed the effects of four weak organic acids differing in lipophilicity (sorbic, benzoic, propionic, and acetic acids) on growth and intracellular pH (pHi) in Saccharomyces cerevisiae. Although lipophilicity of the acids correlated with the rate of acidification of the cytosol, our data confirmed that not initial acidification, but rather the cell's ability to restore pHi, was a determinant for growth inhibition. This pHi recovery in turn depended on the nature of the organic anion. We identified long-term acidification as the major cause of growth inhibition under acetic acid stress. Restoration of pHi, and consequently growth rate, in the presence of this weak acid required the full activity of the plasma membrane ATPase Pma1p. Surprisingly, the proposed anion export pump Pdr12p was shown to play an important role in the ability of yeast cells to restore the pHi upon lipophilic (sorbic and benzoic) acid stress, probably through a charge interaction of anion and proton transport. PMID:23001666

Ullah, Azmat; Orij, Rick; Brul, Stanley

2012-01-01

345

Dynamics of phenolic acids and lignin accumulation in metal-treated Matricaria chamomilla roots.  

PubMed

Phenylalanine ammonia-lyase (PAL) activity, 11 phenolic acids and lignin accumulation in Matricaria chamomilla roots exposed to low (3 microM) and high (60 and 120 microM) levels of cadmium (Cd) or copper (Cu) for 7 days were investigated. Five derivatives of cinnamic acid (chlorogenic, p-coumaric, caffeic, ferulic and sinapic acids) and six derivatives of benzoic acid (protocatechuic, vanillic, syringic, p-hydroxybenzoic, salicylic acids and protocatechuic aldehyde) were detected. Accumulation of glycoside-bound phenolics (revealed by acid hydrolysis) was enhanced mainly towards the end of the experiment, being more expressive in Cu-treated roots. Interestingly, chlorogenic acid was extremely elevated by the highest Cu dose (21-fold higher than control) suggesting its involvement in antioxidative protection. All compounds, with the exception of chlorogenic acid, were detected in the cell wall bound fraction, but only benzoic acids were found in the ester-bound fraction (revealed by alkaline hydrolysis). Soluble phenolics were present in substantially higher amounts in Cu-treated roots and more Cu was retained there in comparison to Cd. Cu strongly elevated PAL activity (by 5.4- and 12.1-fold in 60 and 120 microM treatment, respectively) and lignin content (by 71 and 148%, respectively) after one day of treatment, indicating formation of a barrier against metal entrance. Cd had slighter effects, supporting its non-redox active properties. Taken together, different forms of phenolic metabolites play an important role in chamomile tolerance to metal excess and participate in active antioxidative protection. PMID:18066553

Kovácik, Jozef; Klejdus, Borivoj

2008-03-01

346

Phenolic acid composition and antioxidant properties of Malaysian honeys.  

PubMed

The phenolic acid and flavonoid contents of Malaysian Tualang, Gelam, and Borneo tropical honeys were compared to those of Manuka honey. Ferric reducing/antioxidant power assay (FRAP) and the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activities were also quantified. All honey extracts exhibited high phenolic contents (15.21 ± 0.51- 42.23 ± 0.64 mg/kg), flavonoid contents (11.52 ± 0.27- 25.31 ± 0.37 mg/kg), FRAP values (892.15 ± 4.97- 363.38 ± 10.57 ?M Fe[II]/kg), and high IC?? of DPPH radical-scavenging activities (5.24 ± 0.40- 17.51 ± 0.51 mg/mL). Total of 6 phenolic acids (gallic, syringic, benzoic, trans-cinnamic, p-coumaric, and caffeic acids) and 5 flavonoids (catechin, kaempferol, naringenin, luteolin, and apigenin) were identified. Among the Malaysian honey samples, Tualang honey had the highest contents of phenolics, and flavonoids, and DPPH radical-scavenging activities. We conclude that among Malaysian honey samples, Tualang honey is the richest in phenolic acids, and flavonoid compounds, which have strong free radical-scavenging activities. PMID:22417491

Khalil, M I; Alam, N; Moniruzzaman, M; Sulaiman, S A; Gan, S H

2011-08-01

347

Molecular Structure of Butyric acid  

NSDL National Science Digital Library

n-Butyric acid is a substance that was isolated from butter in 1869. Butyric acid means, in Latin, the acid of butter as it was first discovered in rancid butter. It is found most commonly in butter, but can also be present in some fruits. Butyric acid is also produced synthetically, through fermentation of various carbohydrates, to be used as a flavoring agent in various food products. Applications of butyric acid are as an additive to food, flavorings, varnishes, perfumes, pharmaceuticals and disinfectants. It is also used for the production of plastics, plasticizers, surfactants and textile auxiliaries. Butyric acid and its derivatives are also being seriously considered around the world as potential anticancer agents.

2002-10-11

348

Shaping up nucleic acid computation  

PubMed Central

Summary of recent advances (abstract) Nucleic acid-based nanotechnology has always been perceived as novel, but has begun to move from theoretical demonstrations to practical applications. In particular, the large address spaces available to nucleic acids can be exploited to encode algorithms and/or act as circuits, and thereby process molecular information. In this review we revisit several milestones in the field of nucleic acid-based computation, but also highlight how the prospects for nucleic acid computation go beyond just a large address space. Functional nucleic acid elements (aptamers, ribozymes, and deoxyribozymes) can serve as inputs and outputs to the environment, and can act as logical elements. Into the future, the chemical dynamics of nucleic acids may prove as useful as hybridization for computation. PMID:20538451

Chen, Xi

2010-01-01

349

Molecular Structure of Salicylic acid  

NSDL National Science Digital Library

Salicylic acid is a colorless to white crystalline powder with a sweetish acrid taste that occurs naturally in many microorganisms and plants in very small amounts. It is also made synthetically and used as preservative of food products in some countries and as an antiseptic in mouthwashes and toothpastes. This chemical is also used in the manufacture of methyl salicylates, acetylasalicylic acid (aspirin) and other salicylates. Salicylic acid is a chemical intermediate in the synthesis of dyestuff, salicylate esters and salts. It is prepared commercially by heating sodium phenolate (the sodium salt of phenol) with carbon dioxide under pressure to form sodium salicylate, which is treated with sulfuric acid to liberate salicylic acid. Salicylic acid is quite irritating to skin and mucosa and it destroys epithelial cells. Absorption of large amounts can cause vomiting, abdominal pain, acidosis and mental disturbances.

2004-11-11

350

Clinical use of acid steatocrit.  

PubMed

Malabsorption of fat is an important gastrointestinal cause of malnutrition and growth retardation in childhood. The gold standard for the evaluation of fat malabsorption is the faecal fat balance method. The acid steatocrit method has recently been introduced as a simple method to evaluate faecal fat. The present study was aimed at evaluating the acid steatocrit in clinical practice. Faecal fat excretion and acid steatocrit results were determined in 42 children, half with and half without fat malabsorption. Acid steatocrit results correlated significantly with both faecal fat excretion (p < 0.01) and faecal fat concentration (p < 0.001). Sensitivity and specificity of the acid steatocrit for the diagnosis of malabsorption were 90% and 100%, respectively. We consider the acid steatocrit method useful for the screening and monitoring of patients with steatorrhoea. PMID:9183483

Van den Neucker, A; Pestel, N; Tran, T M; Forget, P P; Veeze, H J; Bouquet, J; Sinaasappel, M

1997-05-01

351

Production of polymalic acid and malic acid by Aureobasidium pullulans fermentation and acid hydrolysis.  

PubMed

Malic acid is a dicarboxylic acid widely used in the food industry and also a potential C4 platform chemical that can be produced from biomass. However, microbial fermentation for direct malic acid production is limited by low product yield, titer, and productivity due to end-product inhibition. In this work, a novel process for malic acid production from polymalic acid (PMA) fermentation followed by acid hydrolysis was developed. First, a PMA-producing Aureobasidium pullulans strain ZX-10 was screened and isolated. This microbe produced PMA as the major fermentation product at a high-titer equivalent to 87.6?g/L of malic acid and high-productivity of 0.61?g/L?h in free-cell fermentation in a stirred-tank bioreactor. Fed-batch fermentations with cells immobilized in a fibrous-bed bioreactor (FBB) achieved the highest product titer of 144.2?g/L and productivity of 0.74?g/L?h. The fermentation produced PMA was purified by adsorption with IRA-900 anion-exchange resins, achieving a ?100% purity and a high recovery rate of 84%. Pure malic acid was then produced from PMA by hydrolysis with 2?M sulfuric acid at 85°C, which followed the first-order reaction kinetics. This process provides an efficient and economical way for PMA and malic acid production, and is promising for industrial application. PMID:23436475

Zou, Xiang; Zhou, Yipin; Yang, Shang-Tian

2013-08-01

352

Racemization of Meteoritic Amino Acids  

Microsoft Academic Search

Meteorites may have contributed amino acids to the prebiotic Earth, affecting the global ratio of right-handed to left-handed (D\\/L) molecules. We calculate D\\/L ratios for seven biological, alpha-hydrogen, protein amino acids over a variety of plausible parent body thermal histories, based on meteorite evidence and asteroid modeling. We show that amino acids in meteorites do not necessarily undergo complete racemization

Barbara A. Cohen; Christopher F. Chyba

2000-01-01

353

Certain derivatives of aminomethylphosphonic acid  

Microsoft Academic Search

Summary 1.Experiments on the acylatlon of aminomethylphosphonic acid show that it proceeds with greater difficulty than the acylation of glycine. Acetamidomethyl-, (chloroacetamido)methyl-, and phthalimidamethyl-phosphonic acids have been prepared.2.The methylation of aminomethylphosphonic acid has been effected by means of methyl iodide in a methanol mediums, and it has been shown that a quaternary iodide derived from the phosphonobetaine is formed. It

Me Io Kabachnik; T. Ya. Medved

1953-01-01

354

Polyaminopolycarboxylic Acids derived from Polyethyleneamines  

Microsoft Academic Search

THE effects of increasing length of the alkylene bridge on acid dissociation constants and metal chelate stability constants of homologues of ethylene-diaminetetra-acetic acid derived from polymethylene-diamines have been reported within recent years1. The effects of an increase in the polydentate and polyelectrolyte nature of polyaminopolycarboxylic acids derived from polyethylene polyamines have not been investigated except for a brief report on

Albert E. Frost

1956-01-01

355

All-trans retinoic acid regulates hepatic bile acid homeostasis.  

PubMed

Retinoic acid (RA) and bile acids share common roles in regulating lipid homeostasis and insulin sensitivity. In addition, the receptor for RA (retinoid x receptor) is a permissive partner of the receptor for bile acids, farnesoid x receptor (FXR/NR1H4). Thus, RA can activate the FXR-mediated pathway as well. The current study was designed to understand the effect of all-trans RA on bile acid homeostasis. Mice were fed an all-trans RA-supplemented diet and the expression of 46 genes that participate in regulating bile acid homeostasis was studied. The data showed that all-trans RA has a profound effect in regulating genes involved in synthesis and transport of bile acids. All-trans RA treatment reduced the gene expression levels of Cyp7a1, Cyp8b1, and Akr1d1, which are involved in bile acid synthesis. All-trans RA also decreased the hepatic mRNA levels of Lrh-1 (Nr5a2) and Hnf4? (Nr2a1), which positively regulate the gene expression of Cyp7a1 and Cyp8b1. Moreover, all-trans RA induced the gene expression levels of negative regulators of bile acid synthesis including hepatic Fgfr4, Fxr, and Shp (Nr0b2) as well as ileal Fgf15. All-trans RA also decreased the expression of Abcb11 and Slc51b, which have a role in bile acid transport. Consistently, all-trans RA reduced hepatic bile acid levels and the ratio of CA/CDCA, as demonstrated by liquid chromatography-mass spectrometry. The data suggest that all-trans RA-induced SHP may contribute to the inhibition of CYP7A1 and CYP8B1, which in turn reduces bile acid synthesis and affects lipid absorption in the gastrointestinal tract. PMID:25175738

Yang, Fan; He, Yuqi; Liu, Hui-Xin; Tsuei, Jessica; Jiang, Xiaoyue; Yang, Li; Wang, Zheng-Tao; Wan, Yu-Jui Yvonne

2014-10-15

356

Removal of salicylic acid on perovskite-type oxide LaFeO3 catalyst in catalytic wet air oxidation process.  

PubMed

It has been found that salicylic acid can be removal effectively at the lower temperature of 140 degrees C on perovskite-type oxide LaFeO3 catalyst in the catalytic wet air oxidation (CWAO) process. Under the same condition, the activities for the CWAO of phenol, benzoic acid and sulfonic salicylic acid have been also investigated. The results indicated that, with compared to the very poor activities for phenol and benzoic acid, the activities for salicylic acid and sulfonic salicylic acid were very high, which are attributed to their same intramolecular H-bonding structures. With the role of hard acidity of intramolecular H-bonding, salicylic acid and sulfonic salicylic acid can be adsorbed effectively on the basic center of LaFeO3 catalyst and are easy to take place the total oxidation reaction. However, at temperatures higher than 140 degrees C, the intramolecular H-bonding structure of salicylic acid was destroyed and the activities at 160 and 180 degrees C decreased greatly, which confirms further the key role of intramolecular H-bonding in the CWAO. Moreover, the LaFeO3 catalyst also indicated a superior stability of activity and structure in CWAO of salicylic acid. PMID:16870333

Yang, Min; Xu, Aihua; Du, Hongzhang; Sun, Chenglin; Li, Can

2007-01-01

357

Organic Acid Production by Basidiomycetes  

PubMed Central

Sixty-seven strains belonging to 47 species of Basidiomycetes were examined for their acid-producing abilities in glucose media, in both the presence and absence of CaCO3, in stationary and shake cultures. Some strains were found to produce large quantities of oxalic acid. The oxalic acid-producing strains could be separated into two groups. Strains of one group (mostly brown-rot fungi) were able to produce oxalic acid, regardless of whether CaCO3 was present in the medium. Strains of the other group (mostly white-rot fungi) were characterized by their ability to produce oxalic acid only when CaCO3 was added to the medium. With the latter group, shake-culturing was generally more effective than stationary culturing in respect to acid production. In the CaCO3-containing media, Schizophyllum commune, Merulius tremellosus, and Porodisculus pendulus were found to produce substantial amounts of L-malic acid as a main metabolic product, along with small quantities of oxalic and other acids in shake cultures. Especially, S. commune and M. tremellosus may be employed as malic acid-producing species. PMID:5867653

Takao, Shoichi

1965-01-01

358

[Ulcer therapy without acid inhibition].  

PubMed

The mechanism of action of ulcer drugs without acid inhibition appears to involve improvement of defensive factors of the gastroduodenal mucosa. The concept of ulcer healing without acid inhibition is attractive for theoretical reasons, because doubts have arisen about the safety of elevation of intragastric pH, especially in long-term treatment of peptic ulcer disease. Ulcer drugs that do not affect gastric acidity may therefore be preferred, provided they compare favorably to the best acid inhibitors available in terms of efficacy, adverse effects and other requirements. Among these drugs, sucralfate fulfills these criteria to a large extent. PMID:6547542

Koelz, H R

1984-05-19

359

Molecular Structure of Lauric acid  

NSDL National Science Digital Library

Lauric acid was first discovered in lauraceae seeds by Marsson T in 1849. The highest content of lauric acid is found in a mother's breast milk and lauraceae seeds. It is used in foods such as vegetable shortenings as a defoaming agent and industrially as a booster for soaps and detergents. Also it is used in cosmetics, insecticides, and food additives. Additionally, Lauric acid is a medium chain fatty acid, which forms monolaurin in the human or animal body. This compound is an antiviral, antibacterial, and antiprotozoal monoglyceride that destroys lipid coated viruses such as HIV, herpes, cytomegalovirus, and influenza.

2002-10-11

360

Acidic gas capture by diamines  

DOEpatents

Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.9 moles per mole of piperazine.

Rochelle, Gary (Austin, TX); Hilliard, Marcus (Missouri City, TX)

2011-05-10

361

The History of Acid Inhibition  

E-print Network

I review here the history of inhibition of gastric acid. References are limited to books and reviews in which detailed citations can be found. ANTACIDS In ancient times, acids were not understood in the modem chemical sense but merely as bitter sour liquids [1]. Some foods were thought acidic, and if the stomach had an ulcer, everything acrid was to be avoided and soothing remedies such as starch and milk used. Antacids neutralize, rather than inhibit, acid secretion but could not be rationally prescribed until acids were understood in the modern chemical sense. Hydrochloric acid has been known since the early fifteenth century, thought to be in the stomach by Paracelsus in the sixteenth and by Van Helmont in the seventeenth century, but it was not until 1823 that Prout definitively identified free hydrochloric acid in the gastric juice of man and animals and made quantitative measurements of its concentration. Antacids became widely used only this century, especially in association with Sippytype diets for ulcers [2]. As recently as the 1960s, orthodox gastroenterologists believed that gastric acidity was reduced by minimizing the amount of acid-stimulating foods such

J. H. Barona

1994-01-01

362

Aerobic and Anaerobic Catabolism of Vanillic Acid and Some Other Methoxy-Aromatic Compounds by Pseudomonas sp. Strain PN-1  

PubMed Central

Vanillic acid (4-hydroxy-3-methoxybenzoic acid) supported the anaerobic (nitrate respiration) but not the aerobic growth of Pseudomonas sp. strain PN-1. Cells grown anaerobically on vanillate oxidized vanillate, p-hydroxybenzoate, and protocatechuic acid (3,4-dihydroxybenzoic acid) with O2 or nitrate. Veratric acid (3,4-dimethoxybenzoic acid) but not isovanillic acid (3-hydroxy-4-methoxybenzoic acid) induced cells for the oxic and anoxic utilization of vanillate, and protocatechuate was detected as an intermediate of vanillate breakdown under either condition. Aerobic catabolism of protocatechuate proceeded via 4,5-meta cleavage, whereas anaerobically it was probably dehydroxylated to benzoic acid. Formaldehyde was identified as a product of aerobic demethylation, indicating a monooxygenase mechanism, but was not detected during anaerobic demethylation. The aerobic and anaerobic systems had similar but not identical substrate specificities. Both utilized m-anisic acid (3-methoxybenzoic acid) and veratrate but not o- or p-anisate and isovanillate. Syringic acid (4-hydroxy-3,5-dimethoxybenzoic acid), 3-O-methylgallic acid (3-methoxy-4,5-dihydroxybenzoic acid), and 3,5-dimethoxybenzoic acid were attacked under either condition, and formaldehyde was liberated from these substrates in the presence of O2. The anaerobic demethylating system but not the aerobic enzyme was also active upon guaiacol (2-methoxyphenol), ferulic acid (3-[4-hydroxy-3-methoxyphenyl]-2-propenoic acid), 3,4,5-trimethoxycinnamic acid (3-[3,4,5-trimethoxyphenyl]-2-propenoic acid), and 3,4,5-trimethoxybenzoic acid. The broad specificity of the anaerobic demethylation system suggests that it probably is significant in the degradation of lignoaromatic molecules in anaerobic environments. PMID:16346441

Taylor, Barrie F.

1983-01-01

363

The Friedel–Crafts acylation of aromatic compounds with carboxylic acids by the combined use of perfluoroalkanoic anhydride and bismuth or scandium triflate  

Microsoft Academic Search

Aromatic ketones were synthesized by solventless Friedel–Crafts acylation of anisole, mesitylene, xylenes, and toluene with acetic acid and benzoic acid in the presence of trifluoroacetic anhydride by use of bismuth or scandium triflate at 30°C. Toluene, benzene, and even deactivated substrate such as chlorobenzene were benzoylated by the combined use of heptafluorobutyric anhydride and bismuth triflate at 75–100°C. The catalyst

Yoh-ichi Matsushita; Kazuhiro Sugamoto; Takanao Matsui

2004-01-01

364

FT-IR and NMR spectroscopic studies of salicylic acid derivatives. II. Comparison of 2-hydroxy- and 2,4- and 2,5-dihydroxy derivatives  

Microsoft Academic Search

The 2,4- and 2,5-dihydroxybenzamides (8, 9) were syn- thesized from their corresponding methyl esters. The struc- tures and the spectral properties of investigated salicylic acid (1), 2,4- and 2,5-dihydroxy benzoic acids (2, 3), their methyl esters (4-6) and amides (7-9) were analyzed by means of FT-IR and one- and two-dimensional homo- and heteronuclear 1H and 13C NMR spectroscopies. Com- parison

MILENA JADRIJEVI; MLADAR TAKA

365

Decomposition of phenylarsonic acid by AOP processes: degradation rate constants and by-products.  

PubMed

The paper presents results of the studies photodegradation, photooxidation, and oxidation of phenylarsonic acid (PAA) in aquatic solution. The water solutions, which consist of 2.7 g dm(-3) phenylarsonic acid, were subjected to advance oxidation process (AOP) in UV, UV/H2O2, UV/O3, H2O2, and O3 systems under two pH conditions. Kinetic rate constants and half-life of phenylarsonic acid decomposition reaction are presented. The results from the study indicate that at pH 2 and 7, PAA degradation processes takes place in accordance with the pseudo first order kinetic reaction. The highest rate constants (10.45?×?10(-3) and 20.12?×?10(-3)) and degradation efficiencies at pH 2 and 7 were obtained at UV/O3 processes. In solution, after processes, benzene, phenol, acetophenone, o-hydroxybiphenyl, p-hydroxybiphenyl, benzoic acid, benzaldehyde, and biphenyl were identified. PMID:24824504

Jaworek, K; Czaplicka, M; Bratek, L

2014-10-01

366

Highly powerful and practical acylation of alcohols with acid anhydride catalyzed by Bi(OTf)(3).  

PubMed

Bi(OTf)(3)-catalyzed acylation of alcohols with acid anhydride was evaluated in comparison with other acylation methods. The Bi(OTf)(3)/acid anhydride protocol was so powerful that sterically demanding or tertiary alcohols could be acylated smoothly. Less reactive acylation reagents such as benzoic and pivalic anhydride are also activated by this catalysis. In these cases, a new technology was developed in order to overcome difficulty in separation of the acylated product from the remaining acylating reagent: methanolysis of the unreacted anhydride into easily separable methyl ester realized quite easy separation of the desired acylation product. The Bi(OTf)(3)/acid anhydride protocol was applicable to a wide spectrum of alcohols bearing various functionalities. Acid-labile THP- or TBS-protected alcohol, furfuryl alcohol, and geraniol could be acylated as well as base-labile alcohols. Even acylation of functionalized tertiary alcohols was effected at room temperature. PMID:11749624

Orita, A; Tanahashi, C; Kakuda, A; Otera, J

2001-12-28

367

Acid rain on acid soil: a new perspective  

Microsoft Academic Search

Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has

E. C. Krug; C. R. Frink

1983-01-01

368

Acid zeta function and ajoint acid zeta function  

E-print Network

In this paper we set up the theory of acid zeta function and ajoint acid zeta function, based on the theory, we point out a reason to doubt the truth of the Riemann hypothesis and also as a consequence, we give out some new RH equivalences.

Jining Gao

2010-03-16

369

Peptidases and amino acid catabolism in lactic acid bacteria  

Microsoft Academic Search

The conversion of peptides to free amino acids and their subsequent utilization is a central metabolic activity in prokaryotes. At least 16 peptidases from lactic acid bacteria (LAB) have been characterized biochemically and\\/or genetically. Among LAB, the peptidase systems of Lactobacillus helveticus and Lactococcus lactis have been examined in greatest detail. While there are homologous enzymes common to both systems,

Jeffrey E. Christensen; Edward G. Dudley; Jeffrey A. Pederson; James L. Steele

1999-01-01

370

Fast HPLC-ECD analysis of ascorbic acid, dehydroascorbic acid and uric acid.  

PubMed

A robust and rapid high-pressure liquid chromatography-electrochemical detection (HPLC-ECD) method was developed and validated for the accurate determination of ascorbic acid (AA) and uric acid (UA), in human plasma. Dehydroascorbic acid (DHAA) was indirectly measured by subtracting native ascorbic acid from total ascorbic acid concentrations; the latter was obtained after chemical reduction. A stable electrochemical active internal standard (homogentisic acid) was added for the accurate quantification of the analytes. The analyses were performed on a reverse-phase column with traditional HPLC and ultra-HPLC (UHPLC). The UHPLC method showed increased sensitivity with detection limit of 0.05ng for both AA and UA, 2 times lower compared to conventional HPLC. UHPLC also reduced run times fourfold with less waste generation. Both assays showed good accuracy and precision, the intra- and inter-day CVs of AA and UA analysis are less than 7%. PMID:19250886

Li, Xingnan; Franke, Adrian A

2009-04-01

371

Urinary metabolites of flavonoids and hydroxycinnamic acids in humans after application of a crude extract from Equisetum arvense.  

PubMed

Flavonoids and hydroxycinnamic acids are polyphenolic compounds present in our daily diet in form of tea and vegetables as well as in herbal remedies used in phytomedicine. A wide range of in-vitro activities, in particular their antioxidant properties, have been studied intensively. However, in-vivo-data on absorption, bioavailability and metabolism after oral intake are scarce and contradictory. In order to examine the metabolism and renal excretion of these compounds a standardized extract from horsetail (Equisetum arvense) was administered to 11 volunteers following a flavonoid-free diet for 8 d. 24 h urine samples were collected and analyzed by HPLC-DAD. The putative quercetin metabolites, 3,4-dihydroxyphenylacetic acid or 3,4-dihydroxytoluene could not be detected in urine in any sample. The endogenous amount of homovanillic acid, generally regarded as one of the main quercetin metabolites, was 4 +/- 1 mg/d and did not increase significantly. However, hippuric acid, the glycine conjugate of benzoic acid, increased twofold after drug intake. Thus, the degradation to benzoic acid derivatives rather than phenylacetic acid derivatives seems to be a predominant route of metabolism. The results of this pilot study give rise to additional, substantial pharmacokinetic investigations in humans. PMID:10589442

Graefe, E U; Veit, M

1999-10-01

372

Molecular Structure of Isophthalic acid  

NSDL National Science Digital Library

Isophthalic acid is one of the three simple aromatic dicarboxylic acids with the carboxyl groups in the meta postions. It is used to produce isophthalic polyester that together with other components is used in resin systems for flame retardants and in corrosion prevention.

2008-01-10

373

Acetic Acid Catalyzed Carbon Aerogels  

Microsoft Academic Search

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

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

2003-01-01

374

Acid rain & electric utilities II  

SciTech Connect

This document presents reports which were presented at the Acid Rain and Electric Utilities Conference. Topics include environmental issues and electric utilities; acid rain program overview; global climate change and carbon dioxide; emissions data management; compliance; emissions control; allowance and trading; nitrogen oxides; and assessment. Individual reports have been processed separately for the United States Department of Energy databases.

NONE

1997-12-31

375

Ricinoleic acid-based biopolymers.  

PubMed

Polyanhydrides synthesized from pure ricinoleic acid half-esters with maleic and succinic anhydrides possess desired physicochemical and mechanical properties for use as drug carriers. Ricinoleic acid maleate or succinate diacid half-esters were prepared from the reaction of crude ricinoleic acid (85% content) with succinic or maleic anhydride. The pure diacid monomers were obtained by chromatography purification through silica gel using petroleum ether/ethyl acetate/acetic acid (80/30/1 v/v/v) mixture as eluent. The pure diacid monomers (>99%) were polymerized by melt condensation to yield film-forming polymers with molecular weights exceeding 40,000 with a polydispersity of 2. Extensive biocompatibility study demonstrated their toxicological inertness and biodegradability. Their rate of elimination from rats in the course of about 4-6 weeks was faster than that found for similar fatty acid-based polyanhydrides previously tested. In vitro studies showed that these polymers underwent rapid hydrolytic degradation in 10 days. Methotrexate release from the polymers was not affected by the initial polymer molecular weight in the range of 10,000-35,000. The in vitro drug release correlated with the degradation of the polymers. The fatty acid ester monomers were further degraded to its counterparts, ricinoleic acid and succinic or maleic acid. PMID:10397984

Teomim, D; Nyska, A; Domb, A J

1999-06-01

376

Acid Precipitation: Causes and Consequences.  

ERIC Educational Resources Information Center

This article is the first of three articles in a series on the acid rain problem in recent years. Discussed are the causes of acid precipitation and its consequences for the abiotic and biotic components of the terrestrial and aquatic ecosystems, and for man-made materials. (Author/SA)

Babich, Harvey; And Others

1980-01-01

377

The Canadian acid rain strategy  

Microsoft Academic Search

In November 1994, Canadian Energy and Environment Ministers announced their intention to develop a long-term domestic acid rain strategy for post-2000. The strategy would address the need for further emission reductions within Canada as well as the need for further emission reductions in the United States for those sources and pollutants that result in continuing negative impacts from acid deposition

G Fenech

1998-01-01

378

The Acid Rain Differential Game  

Microsoft Academic Search

This paper considers an acid rain differential game. Countries emit sulphur which is partly transferred to other countries. Depositions above critical loads ultimately destroy the soil. Countries face a trade-off between the costs of emission reductions and the damage to the soil due to the depletion of the acid buffers. Because of the transboundary externalities the outcome will depend on

Karl-Göran Mäler; Aart De Zeeuw

1998-01-01

379

Acid-Base Titration Applet  

NSDL National Science Digital Library

Acid-Base titration applet that plots pH changes as student adds acid or base. Gives choice of indicators (only two right now). Compares plots for titration of traditional solution and a buffered solution (several choices for comparison). Can alter starting concentrations.

Usc

380

Acid rain: facts and fallacies  

Microsoft Academic Search

Acid rain is a complex environmental problem that is hard to define in terms of sources and effects. Major sources are thought to be atmospheric emissions, mostly from urban sources, although exact locations and the means by which emissions are transformed to acid rain are not entirely clear. Lack of long-term records has made it difficult to determine how fast

1981-01-01

381

Acid Resistance in Mycobacterium tuberculosis  

Microsoft Academic Search

Responses to acid have been studied extensively in enteric pathogens, such as Escherichia coli, Vibrio cholerae, and Heli- cobacter pylori that encounter the extremely low pH (pH 2 to 3) of the stomach during ingestion. In contrast, much less is known about how obligate or facultative intracellular bacterial pathogens like Mycobacterium tuberculosis respond, resist, and persist in the moderately acid

Omar H. Vandal; Carl F. Nathan; Sabine Ehrt

2009-01-01

382

Acid Rain: A Background Report.  

National Technical Information Service (NTIS)

This Staff Brief was prepared for the Wisconsin Legislative Council's Special Committee on Acid Rain to provide an introduction to the issue of acid rain. It is divided into four parts. Part I provides an overview on the controversies surrounding the meas...

L. Glustrom, J. Stolzenberg

1982-01-01

383

Advanced Lead Acid Battery Development.  

National Technical Information Service (NTIS)

Researchers at the University of Idaho have been investigating the possibility of using lead acid batteries in electric and hybrid vehicles for more than ten years, and the funding from UTC Program helped support this continuing effort. The lead acid batt...

D. Edwards, C. Kinney

2001-01-01

384

SOIL REACTION AND ACIDIC DEPOSITION  

EPA Science Inventory

This chapter discusses the major chemical processes by which acidic deposition interacts with soils. he focus is on forest soils, as the effects of acidic deposition on soils used for production of food and fiber are generally small compared to effects of agricultural practices s...

385

SIMULATED ACID RAIN ON CROPS  

EPA Science Inventory

In 1981, simulated H2SO4 acid rain was applied to alfalfa and tall fescue and a 2:1 ratio of H2SO4:HNO3 acid rain was applied to alfalfa, tall fescue, barley, wheat, potato, tomato, radish, and corn crops growing in the open field at Corvallis, Oregon. Careful attention was given...

386

Bioelectric neutralization of acid waters  

Microsoft Academic Search

An apparatus is to be used in a process for bioelectric neutralization of a body of water having a bottom of anaerobic mud and an acid supernatant liquid. The apparatus comprises a buoy riding on the surface of the water, and upper electrode preferably of carbon suspended from the buoy in the acid supernatant liquid, a lower electrode preferably of

F. D. Sisler; F. E. Senftle

1978-01-01

387

Acetic acid bacteria in oenology  

Microsoft Academic Search

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

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

388

Acid Tests and Basic Fun.  

ERIC Educational Resources Information Center

Explores acids and bases using different indicators, such as turmeric, purple grape juice, and lichens. Because some of these indicators are not as sensitive as cabbage juice or litmus paper, determining to which acids and bases each indicator is sensitive presents an enjoyable, problem-solving challenge for students. Presents directions for…

McBride, John W.

1995-01-01

389

Molecular Structure of Formic acid  

NSDL National Science Digital Library

Formic Acid, also known as methanoic acid and hydrogencarboxylic acid, is the simplest organic acid. It is a colorless, toxic, corrosive liquid with a pungent, penetrating odor. In nature, it is found in the stings and bites of many insects of the order hymenoptera, including bees and ants. The principal use of formic acid is as a preservative and antibacterial agent in livestock feed. The largest single use of formic acid is as a silage additive in Europe, but this market hardly exists in the United States. When sprayed on fresh hay or other silage, it arrests certain decay processes and causes the feed to retain its nutritive value longer. In the poultry industry, it is sometimes added to silage to kill salmonella bacteria. It is also used in textile dyeing, leather tanning, as a solvent, in electroplating processes, in the manufacturing of lacquers, glass, vinyl resin plasticizers, and formate esters (for flavor and fragrance) and in the manufacture of fumigants. Formic acid is a strong reducing agent, and may act both as an acid and as an aldehyde because the carboxyl is bound to a hydrogen rather than an alkyl group.

2003-05-08

390

Acid precipitation in historical perspective  

Microsoft Academic Search

The history of acid precipitation is traced from the first awareness of the problem in the mid-17th century to the present. An outline of the National Acid Precipitation Assessment program is also given, and the author makes recommendations for future research. (JMT)

Ellis B. Cowling

1982-01-01

391

BOTANICAL ASPECTS OF ACIDIC PRECIPITATION  

EPA Science Inventory

Acidic precipitation can be characterized as wet or frozen atmospheric deposition with a hydrogen ion concentration greater than 2.5 microequivalents liter-1. Acidic precipitation is perceived as a significant air pollution problem derived chiefly from combustion of fossil fuels,...

392

Distillation Separation of Hydrofluoric Acid and Nitric Acid from Acid Waste Using the Salt Effect on Vapor-Liquid Equilibrium  

NASA Astrophysics Data System (ADS)

This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor-liquid equilibrium for acid aqueous solutions and acid mixtures. The vapor-liquid equilibrium of hydrofluoric acid + salt systems (fluorite, potassium nitrate, cesium nitrate) was measured using an apparatus made of perfluoro alkylvinylether. Cesium nitrate showed a salting-out effect on the vapor-liquid equilibrium of the hydrofluoric acid-water system. Fluorite and potassium nitrate showed a salting-in effect on the hydrofluoric acid-water system. Separation of hydrofluoric acid from an acid mixture containing nitric acid and hydrofluoric acid was tested by the simple distillation treatment using the salt effect of cesium nitrate (45 mass%). An acid mixture of nitric acid (5.0 mol · dm-3) and hydrofluoric acid (5.0 mol · dm-3) was prepared as a sample solution for distillation tests. The concentration of nitric acid in the first distillate decreased from 5.0 mol · dm-3 to 1.13 mol · dm-3, and the concentration of hydrofluoric acid increased to 5.41 mol · dm-3. This first distillate was further distilled without the addition of salt. The concentrations of hydrofluoric acid and nitric acid in the second distillate were 7.21 mol · dm-3 and 0.46 mol · dm-3, respectively. It was thus found that the salt effect on vapor-liquid equilibrium of acid mixtures was effective for the recycling of acids from acid mixture wastes.

Yamamoto, Hideki; Sumoge, Iwao

2011-03-01

393

Atmospheric dust and acid rain  

SciTech Connect

Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid rain and atmospheric dust? Suggestions range from the improbable to the feasible. One reasonable suggestion is to reduce emissions of acidic pollutants to levels that can be buffered by natural quantities of basic compounds in the atmosphere; such a goal would mean continued reductions in sulfur dioxide and nitrogen oxides, perhaps even greater than those prescribed in the 1990 Amendments to the Clean Air Act in the U.S. 5 figs.

Hedin, L.O.; Likens, G.E.

1996-12-01

394

Direct formic acid fuel cells  

NASA Astrophysics Data System (ADS)

The performance of formic acid fuel oxidation on a solid PEM fuel cell at 60 °C is reported. We find that formic acid is an excellent fuel for a fuel cell. A model cell, using a proprietary anode catalyst produced currents up to 134 mA/cm 2 and power outputs up to 48.8 mW/cm 2. Open circuit potentials (OCPs) are about 0.72 V. The fuel cell runs successfully over formic acid concentrations between 5 and 20 M with little crossover or degradation in performance. The anodic polarization potential of formic acid is approximately 0.1 V lower than that for methanol on a standard Pt/Ru catalyst. These results show that formic acid fuel cells are attractive alternatives for small portable fuel cell applications.

Rice, C.; Ha, S.; Masel, R. I.; Waszczuk, P.; Wieckowski, A.; Barnard, Tom

395

Fumaric acid production by fermentation.  

PubMed

The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations. PMID:18214471

Roa Engel, Carol A; Straathof, Adrie J J; Zijlmans, Tiemen W; van Gulik, Walter M; van der Wielen, Luuk A M

2008-03-01

396

Fumaric acid production by fermentation  

PubMed Central

The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations. PMID:18214471

Roa Engel, Carol A.; Zijlmans, Tiemen W.; van Gulik, Walter M.; van der Wielen, Luuk A. M.

2008-01-01

397

Molecular Structure of Stearic acid  

NSDL National Science Digital Library

Stearic acid is white leaflets, slightly yellow crystal masses or a white to slightly yellow powder. Stearic acid is a saturated fatty acid found in low percentages in cotton, coconut, palm kernel, corn, palm, castor, rapeseed, soybean, sunflower, herring, and tallow oils. It is also one of the fat components found in the cocoa butter of chocolate. It is prepared synthetically by hydrogenation of cottonseed and other vegetable oils or by treating animal fat with water at a high pressure and temperature. Stearic acid is useful as an ingredient in making candles, soaps, and for softening synthetic rubber. It is also a component of cosmetic formulations, pharmaceuticals creams and vanishing lotion. Stearic acid is practically nontoxic but the dust is irritating to eyes, nose, and throat and the solid is irritating to skin and eyes.

2004-11-11

398

Molecular Structure of Galacturonic acid  

NSDL National Science Digital Library

Galacturonic acid is the monobasic acid resulting from oxidation of the primary alcohol group of D-galactose to carboxyl. It is widely distributed as a constituent of pectins (compounds with heterogeneous grouping of acidic structural polysaccharides, found in fruit and vegetables), many plant gums, and mucilages (gummy substances obtained from certain plants, which are used as food stabilizers). Gums tend to be used as thickening and bulking agents in pharmaceutics, and they play a less obvious part in most plants. Once swallowed, their actions are no different from those of the mucilages. D-Galacturonic acid prepared from pectin can be used to synthesize vitamin C. Native pectin is a mixture of polysaccharides, with the major component a polymer of -D-galacturonic acid. Pectin has numerous other medical and pharmaceutical uses, for example in combination with plant hemicelluloses and lignin, may be useful dietary constituents in preventing coronary heart disease, diverticular disease, ulcerative colitis, and a variety of other Western diseases.

2003-05-08

399

Molecular Structure of Linoleic acid  

NSDL National Science Digital Library

Linoleic acid is a polyunsaturated fatty acid occurring widely in plant glycerides or fats. Common sources include many vegetable oils such as flax seed, safflower, soybean, peanut, and corn; some margarines; and dairy fats. It is a colorless to straw-colored liquid, insoluble in water, but soluble in alcohol and ether. Linoleic acid is easily oxidized by air and is combustible. It also appears as an aluminum salt, in the form of yellow lumps or powder, that is practically insoluble in water but soluble in oils and fixed alkalai hydroxides. Linoleic acid is essential in human nutrition and is used also for soaps, animal feeds, paints, drying protective coatings, emulsifying or smoothing and wetting agents, and in biochemical research. The conjugated form of linoleic acid or CLA has been associated with health benefits such as lowered risk of cancer and atherosclerosis. Prepared CLA is available as a supplement. However, foods high in CLA content could be used.

2003-05-08

400

Synthesis of l-(+)-Tartaric Acid from l-Ascorbic Acid via 5-Keto-d-Gluconic Acid in Grapes  

PubMed Central

5-Keto-l-idionic acid (?5-keto-d-gluconic acid, d-xylo-5-hexulosonic acid) was found as a metabolic product of l-ascorbic acid in slices of immature grapes, Vitis labrusca L. cv `Delaware'. Specifically labeled compounds, recognized as metabolic products of l-ascorbic acid in grapes, were fed to young grape tissues to investigate the metabolic pathway from l-ascorbic acid to l-(+)-tartaric acid. Label from dehydro-l-[1-14C]ascorbic acid, 2-keto-l-[1-14C]idonic acid (l-xylo-2-hexulosonic acid), l-[1-14C]idonic acid, or 5-keto-l-[1-14C] idonic acid was incorporated into l-(+)-tartaric acid in high yields as it was in the l-[1-14C]ascorbic acid experiment. In a double label experiment involving a mixture of l-[1-14C]idonic acid and l-[2-3H]idonic acid, the 3H/14C ratios of 5-keto-l-idonic acid and l-(+)-tartaric acid synthesized in young grape leaves were almost the same as the value of the l-idonic acid fed. Label from 5-keto-l-[6-14C]idonic acid was incorporated into sugars and insoluble residue in the same way as l-[6-14C]ascorbic acid was metabolized in grapes. These results provide strong evidence that in grapes l-(+)-tartaric acid is synthesized from the C4 fragment that corresponds to the C1 to C4 group of the 5-keto-l-idonic acid derived from l-ascorbic acid via 2-keto-l-idonic acid and l-idonic acid. PMID:16663792

Saito, Kazumi; Kasai, Zenzaburo

1984-01-01

401

The ascorbic acid paradox.  

PubMed

Ascorbic acid (AA) is a common culture medium and dietary supplement. While AA is most commonly known for its antioxidant properties, it is also known to function as a pro-oxidant under select conditions. However, the complexity and often unknown composition of biological culture systems makes prediction of AA behaviour in supplemented cultures challenging. The frequent observation of outcomes inconsistent with antioxidant behaviour suggests that AA may be playing a pro-oxidant role more often than appreciated. In this work we explored the intracellular and extracellular impact of AA supplementation on KG1a myeloid leukaemia cells over a 24-h culture period following the addition of the AA supplement. At 24h we found that supplementation of AA up to 250?M resulted in intracellular antioxidant behaviour. However, when these same cultures were evaluated at 2 or 4h we observed pro-oxidant activity at the higher AA concentrations indicating that the outcome was very much time and dose dependent. In contrast, pro-oxidant activity was never observed in the extracellular medium. Paradoxically, and to our knowledge not previously reported, we observed that intracellular pro-oxidant activity and extracellular antioxidant activity could occur simultaneously. These results indicate that the precise activity of AA supplementation varies as a function of dose, time and cellular location. Further, these results demonstrate how in the absence of careful culture characterization the true impact of AA on cultures could be underappreciated. PMID:20732307

Osiecki, Michael; Ghanavi, Parisa; Atkinson, Kerry; Nielsen, Lars K; Doran, Michael R

2010-10-01

402

Lead-acid battery  

NASA Technical Reports Server (NTRS)

A light weight lead-acid battery (30) having a positive terminal (36) and a negative terminal (34) and including one or more cells or grid stacks having a plurality of vertically stacked conductive monoplates (10, 20) with positive active material and negative active material deposited on alternating plates in the cell or grid stack. Electrolyte layers (26, 28) positioned between each monoplate are included to provide a battery cell having four sides which is capable of being electrically charged and discharged. Two vertical positive bus bars (42, 43) are provided on opposite sides of the battery cell for connecting the monoplates (10) with positive active material together in parallel current conducting relation. In addition, two negative bus bars (38, 39) on opposite sides of the battery cell each being adjacent the positive bus bars are provided for connecting the monoplates (20) with negative active material together in parallel current conducting relation. The positive (42, 43) and negative (38, 39) bus bars not only provide a low resistance method for connecting the plurality of conductive monoplates of their respective battery terminals (36, 34) but also provides support and structural strength to the battery cell structure. In addition, horizontal orientation of monoplates (10, 20) is provided in a vertical stacking arrangement to reduce electrolyte stratification and short circuiting due to flaking of positive and negative active materials from the monoplates.

Rowlette, John J. (Inventor)

1983-01-01

403

Acid hydrolysis of sugarcane bagasse for lactic acid production.  

PubMed

In order to use sugarcane bagasse as a substrate for lactic acid production, optimum conditions for acid hydrolysis of the bagasse were investigated. After lignin extraction, the conditions were varied in terms of hydrochloric (HCl) or sulfuric (H(2)SO(4)) concentration (0.5-5%, v/v), reaction time (1-5h) and incubation temperature (90-120 degrees C). The maximum catalytic efficiency (E) was 10.85 under the conditions of 0.5% of HCl at 100 degrees C for 5h, which the main components (in gl(-1)) in the hydrolysate were glucose, 1.50; xylose, 22.59; arabinose, 1.29; acetic acid, 0.15 and furfural, 1.19. To increase yield of lactic acid production from the hydrolysate by Lactococcus lactis IO-1, the hydrolysate was detoxified through amberlite and supplemented with 7 g l(-1) of xylose and 7 g l(-1) of yeast extract. The main products (in gl(-1)) of the fermentation were lactic acid, 10.85; acetic acid, 7.87; formic acid, 6.04 and ethanol, 5.24. PMID:19766480

Laopaiboon, Pattana; Thani, Arthit; Leelavatcharamas, Vichean; Laopaiboon, Lakkana

2010-02-01

404

Formation of acrylic acid from lactic acid in supercritical water  

SciTech Connect

Supercritical (SC) water is an unusual medium in which fast and specific heterolytic reactions can be conducted at temperatures as high as 400{degree}C. In supercritical water, lactic acid decomposes into gaseous and liquid products via three primary reaction pathways. Products of the acid-catalyzed heterolytic decarbonylation pathway are carbon monoxide, water, and acetaldehyde. Products of the homolytic, decarboxylation pathway are carbon dioxide, hydrogen, and acetaldehyde. Products of the heterolytic, dehydration pathway are acrylic acid and water. The intramolecular nucleophilic displacement of the {alpha}-hydroxyl by the carbonyl group of lactic acid, producing {alpha}-propiolactone as an unstable intermediate which subsequently rearranges to become the unsaturated acid, is a likely mechanism for acrylic acid formation, although an intramolecular E2 elimination initiated by attack of the carbonyl oxygen on a methyl hydrogen cannot be ruled out. Support for the former mechanism comes in part from the observed 100% relative yield of acrylic acid from {beta}-propiolactone in SC water.

Mok, W.S.L.; Antal, M.J. Jr. (Univ. of Hawaii, Honolulu (USA)); Jones, M. Jr. (Princeton Univ., NJ (USA))

1989-09-15

405

Reduction of hypervalent chromium in acidic media by alginic acid.  

PubMed

Selective oxidation of carboxylate groups present in alginic acid by Cr(VI) affords CO2, oxidized alginic acid, and Cr(III) as final products. The redox reaction afforded first-order kinetics in [alginic acid], [Cr(VI)], and [H(+)], at fixed ionic strength and temperature. Kinetic studies showed that the redox reaction proceeds through a mechanism which combines Cr(VI)?Cr(IV)?Cr(II) and Cr(VI)?Cr(IV)?Cr(III) pathways. The mechanism was supported by the observation of free radicals, CrO2(2+) and Cr(V) as reaction intermediates. The reduction of Cr(IV) and Cr(V) by alginic acid was independently studied and it was found to occur more than 10(3) times faster than alginic acid/Cr(VI) reaction, in acid media. At pH 1-3, oxo-chromate(V)-alginic acid species remain in solution during several hours at 15°C. The results showed that this abundant structural polysaccharide present on brown seaweeds is able to reduce Cr(VI/V/IV) or stabilize high-valent chromium depending on pH value. PMID:25263857

Bertoni, Fernando A; Bellú, Sebastian E; González, Juan C; Sala, Luis F

2014-12-19

406

Kinetics of aluminum-fulvic acid complexation in acidic waters  

SciTech Connect

A fluorescence technique has been used to study the complex formation kinetics of aluminum with a single metal-free fulvic acid isolated from an Adirondack Mountain forest soil. In the pH range of 3.0-4.5, two kinetically distinguishable components of the fulvic acid mixture have been identified, which define two types of average aluminum binding sites. Both fulvic acid average sites conform to a bidentate chelating binding site kinetic analysis, from which rate and equilibrium parameters have been obtained. From comparison of rate and equilibrium constants of aluminum-salicyclic acid complexation, the authors conclude that the faster reacting component of fulvic acid probably contains salicyclic acid type aluminum binding sites. Results are also compared with those of an aluminum-fluoride kinetic study. Fulvic acid and fluoride react with aluminum by the same mechanism and therefore have the same pH dependence. The dependence of the rate on temperature is, however, quite different for the two reactions. The environmental implications of these findings are discussed. 45 references, 5 figures, 6 tables.

Plankey, B.J.; Patterson, H.H.

1987-06-01

407

?-Oxidation of ?-Chlorinated Fatty Acids  

PubMed Central

Myeloperoxidase-derived HOCl targets tissue- and lipoprotein-associated plasmalogens to generate ?-chlorinated fatty aldehydes, including 2-chlorohexadecanal. Under physiological conditions, 2-chlorohexadecanal is oxidized to 2-chlorohexadecanoic acid (2-ClHA). This study demonstrates the catabolism of 2-ClHA by ?-oxidation and subsequent ?-oxidation from the ?-end. Mass spectrometric analyses revealed that 2-ClHA is ?-oxidized in the presence of liver microsomes with initial ?-hydroxylation of 2-ClHA. Subsequent oxidation steps were examined in a human hepatocellular cell line (HepG2). Three different ?-chlorinated dicarboxylic acids, 2-chlorohexadecane-(1,16)-dioic acid, 2-chlorotetradecane-(1,14)-dioic acid, and 2-chloroadipic acid (2-ClAdA), were identified. Levels of 2-chlorohexadecane-(1,16)-dioic acid, 2-chlorotetradecane-(1,14)-dioic acid, and 2-ClAdA produced by HepG2 cells were dependent on the concentration of 2-ClHA and the incubation time. Synthetic stable isotope-labeled 2-ClHA was used to demonstrate a precursor-product relationship between 2-ClHA and the ?-chlorinated dicarboxylic acids. We also report the identification of endogenous 2-ClAdA in human and rat urine and elevations in stable isotope-labeled urinary 2-ClAdA in rats subjected to intraperitoneal administration of stable isotope-labeled 2-ClHA. Furthermore, urinary 2-ClAdA and plasma 2-ClHA levels are increased in LPS-treated rats. Taken together, these data show that 2-ClHA is ?-oxidized to generate ?-chlorinated dicarboxylic acids, which include ?-chloroadipic acid that is excreted in the urine. PMID:20956542

Brahmbhatt, Viral V.; Albert, Carolyn J.; Anbukumar, Dhanalakshmi S.; Cunningham, Bryce A.; Neumann, William L.; Ford, David A.

2010-01-01

408

Hydrothermal Synthesis, Crystal Structure, and Biological Properties of a Mn(II) Complex with Phenylformic Acid-Imidazole Ditopic Ligand  

Microsoft Academic Search

A new Mn(II) coordination complex derived from 4-(imidazole-1-yl)-benzoic acid was synthesized by hydrothermal method and characterized by X-ray single crystal diffraction. Antimicrobial activity and DPPH free radical scavenging activity of the free ligand and its Mn(II) complex have been tested. The result indicated that the title complex shows stronger activity than the free ligand. The catalytic activity of the title

Jian Gao; Kai-Ju Wei; Jia Ni; Ju-Zhou Zhang

2008-01-01

409

Analysis of Acidic Drugs in Swiss Wastewaters  

Microsoft Academic Search

Five acidic drugs (clofibric acid, ibuprofen, ketoprofen, mefenamic acid and diclofenac) were chosen in order to determine their behavior in a sewage treatment plant (STP). An analytical method using solid phase extraction (SPE) and a gas chromatograph coupled with a mass spectrometer (GC-MS) was used. The results show that four pharmaceuticals (clofibric acid, ketoprofen, mefenamic acid and diclofenac) are not

Benedicte Soulet; Annick Tauxe; Joseph Tarradellas

2002-01-01

410

Combined Acid Catalysis for Asymmetric Synthesis  

E-print Network

Combined Acid Catalysis for Asymmetric Synthesis Michael T. Corbett University of North Carolina, 44, 1924­1942. Limitations of classical Brønsted/Lewis Acid catalysis: · Poor reactivity (low acidity) · Low selectivity · High catalyst loading R X R X HMLn X Lewis Acid Catalysis Brønsted Acid Catalysis X

Johnson, Jeff S.

411

ACID RAIN DEGRADATION OF NYLON (POLYAMIDE, PHOTODEGRADATION)  

Microsoft Academic Search

Acid rain, precipitation with a ph less than 5.6, is known to damage lakes, vegetation and buildings. Degradation of outdoor textiles by acid rain is strongly suspected but not well documented. This study reports the effects of sunlight, aqueous acid, heat and humidity (acid rain conditions) on spun delustered nylon 6,6 fabric. Untreated nylon and nylon treated with sulfuric acid

KAREN E KYLLO

1984-01-01

412

Terahertz spectrum of gallic acid  

NASA Astrophysics Data System (ADS)

Gallic acid is natural polyphenol compound found in many green plants. More and more experiments have demonstrated that the gallic acid has comprehensive applications. In the field of medicine, the gallic acid plays an important role in antianaphylaxis, antineoplastic, antimycotic, anti-inflammatory, antivirotic, antiasthmatic and inhibiting the degradation of insulin. It also has a lot of applications in chemical industry, food industry and light industry. So it is important to study the terahertz time-domain spectroscopy of gallic acid. Terahertz time-domain spectroscopy (THz-TDS) is a new coherent spectral technology based on the femtosecond laser. In this work, the spectral characteristics of gallic acid in the range of 0.4 THz to 2.6 THz have been measured by THz-TDS. We obtained its absorption and refraction spectra at room temperature. The vibration absorption spectrum of the single molecule between 0.4 THz and 2.6 THz is simulated based on the Density Functional Theory (DFT). It is found that the gallic acid has the spectral response to THz wave in this frequency range. The results show the abnormal dispersion at 1.51 THz and 2.05 THz. These results can be used in the qualitative analysis of gallic acid and the medicine and food inspection.

Wu, Meng; Zhao, Guozhong; Wang, Haiyan; Liang, Chengshen

2009-11-01

413

Diabetes and Alpha Lipoic Acid  

PubMed Central

Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E, and glutathione. It also boosts antioxidant defense system through Nrf-2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10?years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy. PMID:22125537

Golbidi, Saeid; Badran, Mohammad; Laher, Ismail

2011-01-01

414

Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region.  

PubMed

A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145 ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ? Erie > Huron > Superior ? Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2 ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045 ± 0.023 ng/g. Mean concentrations of PFOA were not significantly different (p > 0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032 ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid. PMID:22722738

Guo, Rui; Reiner, Eric J; Bhavsar, Satyendra P; Helm, Paul A; Mabury, Scott A; Braekevelt, Eric; Tittlemier, Sheryl A

2012-11-01

415

Acidity dependence of the trifluoromethanesulfonic acid catalyzed isobutane-isobutylene alkylation modified with trifluoroacetic acid or water  

Microsoft Academic Search

Trifluoromethanesulfonic acid (TFSA) catalyzed isobutane-isobutylene alkylation modified with trifluoroacetic acid (TFA) or water, was studied over a wide range of acidity (Ho: ?10.1 to ?14.1). The effect of the acidity of these nonoxidizing strong mixed acid systems on the alkylation, is reported. For both systems, the best alkylation conditions were those at an acid strength of about Ho= ?10.7, giving

George A. Olah; Patrice Batamack; Denis Deffieux; Béla Török; Qi Wang; Árpád Molnár; G. K. Surya Prakash

1996-01-01

416

40 CFR 721.2086 - Coco acid triamine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Coco acid triamine condensate, polycarboxylic acid salts. 721.2086 Section 721.2086 Protection...Specific Chemical Substances § 721.2086 Coco acid triamine condensate, polycarboxylic acid...

2013-07-01

417

Solid acids for green chemistry.  

PubMed

Solid acids and especially those based on micelle-templated silicas and other mesoporous high surface area support materials are beginning to play a significant role in the greening of fine and specialty chemicals manufacturing processes. A wide range of important organic reactions can be efficiently catalyzed by these materials, which can be designed to provide different types of acidity as well as high degrees of reaction selectivity. The solid acids generally have high turnover numbers and can be easily separated from the organic components. The combination of this chemistry with innovative reaction engineering offers exciting opportunities for innovative green chemical manufacturing in the future. PMID:12234209

Clark, James H

2002-09-01

418

Treatment of acid mine wastewaters  

SciTech Connect

Acid mine drainage often results from the oxidation sulfide minerals to form sulfuric acid. As a consequence, high concentrations of metals in the both the suspended and dissolved state result from the low pH water. This paper discusses several of the more common treatment methods for acid mine drainage including the use of chemical precipitation agents, pH correction agents, filtration methods, and biodegradation methods. Advanced treatment technologies are also briefly described and include microfiltration, reverse osmosis, ion exchange, and electrodialysis.

Hayward, D.; Barnard, R.

1993-06-01

419

Can crops tolerate acid rain  

SciTech Connect

This brief article describes work by scientists at the ARS Air Quality-Plant Growth and Development Laboratory in Raleigh, North Carolina, that indicates little damage to crops as a result of acid rain. In studies with simulated acid rain and 216 exposed varieties of 18 crops, there were no significant injuries nor was there reduced growth in most species. Results of chronic and acute exposures were correlated in sensitive tomato and soybean plants and in tolerant winter wheat and lettuce plants. These results suggest that 1-hour exposures could be used in the future to screen varieties for sensitivity to acid rain.

Kaplan, J.K.

1989-11-01

420

Chemiluminescent measurement of atmospheric acid  

NASA Technical Reports Server (NTRS)

The design and construction of a gas phase acid sensitive analyzer are reported. These studies showed that the chemical system was a practical analytical method. A complete instrument was developed and prepared for field testing. A Titan 3-C rocket was scheduled for launching on February 11, 1974. Through preparations made by NASA Langley the instrument was set up to monitor the acid concentration in the rocket exhaust. Due to adverse wind conditions no acid was detected. This entire trip is described in detail.

Stedman, D. H.; Kok, G. L.

1974-01-01

421

Be an acid rain detective  

SciTech Connect

Acid rain is discussed in a question and answer format. The article is aimed at educating sport fishermen on the subject, and also to encourage them to write their congressmen, senators, and the President about the acid rain problem. The article also announces the availability of an acid rain test kit available through the magazine, ''Sports Afield.'' The kit consists of pH-test paper that turns different shades of pink and blue according to the pH of the water tested. The color of the test paper is then compared to a color chart furnished in the kit and an approximate pH can be determined.

Atwill, L.

1982-07-01

422

Degradation of acid red 97 dye in aqueous medium using wet oxidation and electro-Fenton techniques.  

PubMed

Degradation of the acid red 97 dye using wet oxidation, by different oxidants, and electro-Fenton systems was investigated in this study. The oxidation effect of different oxidants such as molecular oxygen, periodate, persulfate, bromate, and hydrogen peroxide in wet oxidation system was compared. Mineralization of AR97 with periodate appeared more effective when compared with that of the other oxidants at equal initial concentration. When 5 mM of periodate was used, at the first minute of the oxidative treatment, the decolorization percentage of AR97 solution at 150 and 200 degrees C reached 88 and 98%, respectively. The total organic carbon removal efficiency at these temperatures also reached 60 and 80%. The degradation of AR97 was also studied by electro-Fenton process. The optimal current value and Fe(2+) concentration were found to be 300 mA and 0.2 mM, respectively. The results showed that electro-Fenton process can lead to 70 and 95% mineralization of the dye solution after 3 and 5h giving carboxylic acids and inorganic ions as final end-products before mineralization. The products obtained from degradation were identified by GC/MS as 1,2-naphthalenediol, 1,1'-biphenyl-4-amino-4-ol, 2-naphthalenol diazonium, 2-naphthalenol, 2,3-dihydroxy-1,4-naphthalenedion, phthalic anhydride, 1,2-benzenedicarboxylic acid, phthaldehyde, 3-hydroxy-1,2-benzenedicarboxylic acid, 4-amino-benzoic acid, and 2-formyl-benzoic acid. PMID:20074850

Kayan, Berkant; Gözmen, Belgin; Demirel, Muhammet; Gizir, A Murat

2010-05-15

423

Organic acids enhance halogen activation on mildly acidic water surfaces  

NASA Astrophysics Data System (ADS)

Iodine species of marine origin are ubiquitous in the marine boundary layer (MBL). They are found over the open ocean (even in the absence of biogenic sources), the Antarctic coast, in rain, aerosols, ice, and snow, and participate in HOx/NOx cycles in the MBL. Surface-active organic acids coating the surface marine microlayer (SML) and marine aerosols could affect their chemical/physical properties. Recent field measurements show that organic acids represent ˜50% of the mass of fog waters collected in the US Gulf Coast. Here we report that I2(g) emissions from the heterogeneous reactions of O3(g) with I- (aq) are dramatically enhanced in the presence of surface-active organic acids under mildly acidic condition that are typical of fine marine aerosols. The amphiphilic weak carboxylic acids appear to promote I2(g) emissions by donating the interfacial protons more efficiently than water itself. We infer that the organic acids coating aerosol particles ejected from ocean's surface films could enhance I2(g) production in the MBL.

Hayase, S.; Enami, S.; Yabushita, A.; Kawasaki, M.; Hoffmann, M. R.; Colussi, A. J.

2011-12-01

424

Alkyl hydroxybenzoic acid derivatives that inhibit HIV-1 protease dimerization.  

PubMed

The therapeutic potential of gallic acid and its derivatives as anti-cancer, antimicrobial and antiviral agents is well known. We have examined the mechanism by which natural gallic acid and newly synthesized gallic acid alkyl esters and related protocatechuic acid alkyl esters inhibit HIV-1 protease to compare the influence of the aromatic ring substitutions on inhibition. We used Zhang-Poorman's kinetic analysis and fluorescent probe binding to demonstrate that several gallic and protecatechuic acid alkyl esters inhibited HIV-1 protease by preventing the dimerization of this obligate homodimeric aspartic protease rather than targeting the active site. The tri-hydroxy substituted benzoic moiety in gallates was more favorable than the di-substituted one in protocatechuates. In both series, the type of inhibition, its mechanism and the inhibitory efficiency dramatically depended on the length of the alkyl chain: no inhibition with alkyl chains less than 8 carbon atoms long. Molecular dynamics simulations corroborated the kinetic data and propose that gallic esters are intercalated between the two N- and C-monomer ends. They complete the ?-sheet and disrupt the dimeric enzyme. The best gallic ester (14 carbon atoms, K(id) of 320 nM) also inhibited the multi-mutated protease MDR-HM. These results will aid the rational design of future generations of non-peptide inhibitors of HIV-1 protease dimerization that inhibit multi-mutated proteases. Finally, our work suggests the wide use of gallic and protocatechuic alkyl esters to dissociate intermolecular ?-sheets involved in protein-protein interactions. PMID:22963666

Flausino, O A; Dufau, L; Regasini, L O; Petrônio, M S; Silva, D H S; Rose, T; Bolzani, V S; Reboud-Ravaux, M

2012-01-01

425

Genetics Home Reference: Sialic acid storage disease  

MedlinePLUS

... testing OMIM Genetic disorder catalog Conditions > Sialic acid storage disease On this page: Description Genetic changes Inheritance ... definitions Reviewed February 2008 What is sialic acid storage disease? Sialic acid storage disease is an inherited ...

426

Background on Net Acid or ARD Potential  

E-print Network

balance that favours net acidity or net alkalinity #12;01-3 ABA Method · For example, we want to calculate acid generating and the amount of acid is determined by titration and expressed in the same units

Boisvert, Jeff

427

Extreme resistance to weak-acid preservatives in the spoilage yeast Zygosaccharomyces bailii?  

PubMed Central

Weak-acid preservatives, such as sorbic acid and acetic acid, are used in many low pH foods to prevent spoilage by fungi. The spoilage yeast Zygosaccharomyces bailii is notorious for its extreme resistance to preservatives and ability to grow in excess of legally-permitted concentrations of preservatives. Extreme resistance was confirmed in 38 strains of Z. bailii to several weak-acid preservatives. Using the brewing yeast Saccharomyces cerevisiae as a control, tests showed that Z. bailii was ~ 3-fold more resistant to a variety of weak-acids but was not more resistant to alcohols, aldehydes, esters, ethers, ketones, or hydrophilic chelating acids. The weak acids were chemically very diverse in structure, making it improbable that the universal resistance was caused by degradation or metabolism. Examination of Z. bailii cell populations showed that extreme resistance to sorbic acid, benzoic acid and acetic acid was limited to a few cells within the population, numbers decreasing with concentration of weak acid to < 1 in 1000. Re-inoculation of resistant sub-populations into weak-acid-containing media showed that all cells now possessed extreme resistance. Resistant sub-populations grown in any weak-acid preservative also showed ~ 100% cross-resistance to other weak-acid preservatives. Tests using 14C-acetic acid showed that weak-acid accumulation was much lower in the resistant sub-populations. Acid accumulation is caused by acid dissociation in the higher pH of the cytoplasm. Tests on intracellular pH (pHi) in the resistant sub-population showed that the pH was much lower, ~ pH 5.6, than in the sensitive bulk population. The hypothesis is proposed that extreme resistance to weak-acid preservatives in Z. bailii is due to population heterogeneity, with a small proportion of cells having a lower intracellular pH. This reduces the level of accumulation of any weak acid in the cytoplasm, thus conferring resistance to all weak acids, but not to other inhibitors. PMID:23856006

Stratford, Malcolm; Steels, Hazel; Nebe-von-Caron, Gerhard; Novodvorska, Michaela; Hayer, Kimran; Archer, David B.

2013-01-01

428

Separation of saturated\\/unsaturated fatty acids  

Microsoft Academic Search

Fatty acid mixtures can be separated into one fraction rich in saturated fatty acids and the other rich in unsaturated acids.\\u000a Since saturated fatty acids have a higher melting point than unsaturated, liquid mixture to be fractionated is cooled to a\\u000a temperature at which the larger part of the saturated acids crystallize, while the greater part of unsaturated acids remain

G. Haraldsson

1984-01-01

429

Quantitative Paper Partition Chromatography of Sialic Acids  

Microsoft Academic Search

RECENTLY, it has been obvious that in most biological materials N-acetylsialic acid (N-acetyl-neuraminic acid) and N-glycolloylsialic acid occur together. By the introduction of a micromethod for the determination of glycollic acid, Klenk and Uhlenbruck1 have made possible the evaluation of the amount of N-glycolloylsialic acid in isolated sialic acids. In search of a more direct method, we tried partition chromatography,

Elisabet Svennerholm; Lars Svennerholm

1958-01-01

430

Nucleic acid arrays and methods of synthesis  

DOEpatents

The present invention generally relates to high density nucleic acid arrays and methods of synthesizing nucleic acid sequences on a solid surface. Specifically, the present invention contemplates the use of stabilized nucleic acid primer sequences immobilized on solid surfaces, and circular nucleic acid sequence templates combined with the use of isothermal rolling circle amplification to thereby increase nucleic acid sequence concentrations in a sample or on an array of nucleic acid sequences.

Sabanayagam, Chandran R. (Allston, MA); Sano, Takeshi (Needham, MA); Misasi, John (Syracuse, NY); Hatch, Anson (Seattle, WA); Cantor, Charles (Del Mar, CA)

2001-01-01

431

Acidic Deposition: Sources and Ecological Effects  

Microsoft Academic Search

Acidic atmospheric deposition, popularly referred to as acid rain, is the transfer of strong acids and acid forming substances\\u000a from the atmosphere to the Earth’s surface. Acidic deposition is comprised of sulfuric and nitric acids, and ammonium derived\\u000a from atmospheric emissions of sulfur dioxide, nitrogen oxides, and ammonia respectively. These compounds are emitted by the\\u000a burning of fossil fuels and

Charles T. Driscoll; Kathy Fallon Lambert; Limin Chen

432

Seasonalepisodic control of acid deposition  

E-print Network

This report contains the climatological, technical and economic factors for episodic and seasonal control of emissions in existing power plants. Analyzing a large data set of acid deposition for the years 1982-85, we find ...

Fay, James A.

1988-01-01

433

Controlling acid rain : policy issues  

E-print Network

The policy and regulatory ramifications of U.S. acid rain control programs are examined; particularly, the alternative of a receptor-oriented strategy as constrasted to emission-oriented proposals (e.g., the Mitchell bill) ...

Fay, James A.

1983-01-01

434

Low acid producing solid propellants  

NASA Technical Reports Server (NTRS)

The potential environmental effects of the exhaust products of conventional rocket propellants have been assessed by various groups. Areas of concern have included stratospheric ozone, acid rain, toxicity, air quality and global warming. Some of the studies which have been performed on this subject have concluded that while the impacts of rocket use are extremely small, there are propellant development options which have the potential to reduce those impacts even further. This paper discusses the various solid propellant options which have been proposed as being more environmentally benign than current systems by reducing HCI emissions. These options include acid neutralized, acid scavenged, and nonchlorine propellants. An assessment of the acid reducing potential and the viability of each of these options is made, based on current information. Such an assessment is needed in order to judge whether the potential improvements justify the expenditures of developing the new propellant systems.

Bennett, Robert R.

1995-01-01

435

Molecular Structure of Abscisic acid  

NSDL National Science Digital Library

Abscisic acid (ABA) was first identified and characterized by Frederick Addicott in 1963. ABA is a naturally occurring compound in plants synthesized partially in the chloroplasts. It is a phytohormone that plays an important role in regulating transpiration, stress responses, germination of seeds and embryogenesis in plants. Abscisic acid influences most aspects of plant growth and development to some level, in part due to interactions with other phytohormones. Abscisic acid also promotes abscission of leaves and fruits, and for this reason the name abscisic is given. This plant hormone is the key factor in the adaptation of the plant to environmental stresses such as salinity, drought or water loss, and freezing temperatures. Abscisic acid promotes dormancy and helps the plant tolerate stressful conditions by suspending primary and secondary growth.

2004-11-09

436

Nitrate and Prussic Acid Poisoning  

E-print Network

Nitrate and prussic acid poisoning in cattle are noninfectious conditions that can kill livestock. This publication explains the causes and symptoms of these conditions as well as preventive measures and sampling and testing steps....

Stichler, Charles; Reagor, John C.

2001-09-05

437

Abiotic synthesis of fatty acids  

NASA Technical Reports Server (NTRS)

The formation of fatty acids by Fischer-Tropsch-type synthesis was investigated with ferric oxide, ammonium carbonate, potassium carbonate, powdered Pueblito de Allende carbonaceous chondrite, and filings from the Canyon Diablo meteorite used as catalysts. Products were separated and identified by gas chromatography and mass spectrometry. Iron oxide, Pueblito de Allende chondrite, and Canyon Diablo filings in an oxidized catalyst form yielded no fatty acids. Canyon Diablo filings heated overnight at 500 C while undergoing slow purging by deuterium produced fatty acids only when potassium carbonate was admixed; potassium carbonate alone also produced these compounds. The active catalytic combinations gave relatively high yields of aliphatic and aromatic hydrocarbons; substantial amounts of n-alkenes were almost invariably observed when fatty acids were produced; the latter were in the range C6 to C18, with maximum yield in C9 or 10.

Leach, W. W.; Nooner, D. W.; Oro, J.

1978-01-01

438

New syntheses of aminoalkylphosphonic acids  

E-print Network

. Because of the ease of formation of diethyl phosphono- acetamide (XII a) from triethyl phosphonoacetate (Vp a), this amide . was chosen for use in the initial preparation of an amino phosphonic acid by the Hofmann reaction. However, each of several.... Because of the ease of formation of diethyl phosphono- acetamide (XII a) from triethyl phosphonoacetate (Vp a), this amide . was chosen for use in the initial preparation of an amino phosphonic acid by the Hofmann reaction. However, each of several...

DeBardeleben, John Frederick

2012-06-07

439

Acid Acclimation by Helicobacter pylori  

NSDL National Science Digital Library

Helicobacter pylori is a Gram-negative neutralophile associated with peptic ulcers and gastric cancer. It has a unique ability to colonize the human stomach by acid acclimation. It uses the pH-gated urea channel, UreI, to enhance urea access to intrabacterial urease and a membrane-anchored periplasmic carbonic anhydrase to regulate periplasmic pH to ~6.1 in acidic media, whereas other neutralophiles cannot regulate periplasmic pH and thus only transit the stomach.

PhD George Sachs (VA Wadsworth Hospital Center for Ulcer Research); David L. Weeks (University of California-Los Angeles David Geffen School of Medicine); Yi Wen (University of California-Los Angeles David Geffen School of Medicine); Elizabeth A. Marcus (University of California-Los Angeles David Geffen School of Medicine); David R. Scott (University of California-Los Angeles David Geffen School of Medicine); Klaus Melchers (Altana Research Institute)

2005-12-01

440

Annual zoledronic acid for osteoporosis.  

PubMed

Zoledronic acid (Aclasta - Novartis) is the first bisphosphonate to be licensed in the UK as a once-yearly intravenous treatment for women with postmenopausal osteoporosis. Promotional materials claim that the drug "provides powerful osteoprotection with yearlong compliance", with "significant 3 year fracture reduction at all key sites". Here we consider whether zoledronic acid has a role in the treatment of women with postmenopausal osteoporosis. PMID:19056701

2008-12-01

441

BranchedChain Amino Acids  

Microsoft Academic Search

The branched-chain amino acids (BCAAs) leucine, isoleucine, and valine are synthesized by bacteria,\\u000a fungi, and plants, but are essential for vertebrates including humans, who must receive them from their\\u000a diet. The interest to construct overproducing industrial strains therefore stems from the need to supplement\\u000a the food or feed with these amino acids to use them in medical treatment and as

Miroslav Pátek

442

Molecular Structure of Glucuronic acid  

NSDL National Science Digital Library

Glucuronic acid is a substance derived from uronic acid, and is found in both plants and animals, usually in combination with phenols or alcohols. It is primarily used in detoxifying drugs and toxins to ensure easy elimination from the body. This substance is soluble in water and alcohol and has a melting point of 165 degrees Celsius. It exhibits mutarotation in the crystal form or its specific rotation of light changes depending on the way the crystals were prepared.

2003-05-08

443

Rainfall acidity in northern Britain  

Microsoft Academic Search

The acidity of rain has attracted considerable international interest during the past decade. An area of enhanced rainfall acidity with its focus in the Low Countries of north-west Europe was identified by the European air chemistry study1 for the period 1955-68, and widespread concern arose as a result of observations that fish populations were decreasing in areas of Scandinavia subject

D. Fowler; J. N. Cape; I. D. Leith; I. S. Paterson; J. W. Kinnaird; I. A. Nicholson

1982-01-01

444

Chemical composition of acid fog  

SciTech Connect

Fog water collected at three sites in Los Angeles and Bakersfield, California, was found to have higher acidity and higher concentrations of sulfate, nitrate, and ammonium than previously observed in atmospheric water droplets. The pH of the fog water was in the range of 2.2 to 4.0. the dominant processes controlling the fog water chemistry appear to be the condensation and evaporation of water vapor on preexisting aerosol and the scavenging of gas-phase nitric acid.

Waldman, J.M.; Munger, J.W.; Jacob, D.J.; Flagan, R.C.; Morgan, J.J.; Hoffmann, M.R.

1982-11-12

445

ACID HYDROLYSIS OF AZIRIDINYL PHOSPHORAMIDES  

Microsoft Academic Search

The acid hydrolysis of two model aziridinyl phosphoramides, l-aziridinylbis(dimethylamino)phosphine oxide (11) and bis(l-aziridinyl) (dimethylamino)phosphine oxide (16), in aqueous acetic acid proceeded by an initial aziridine ring opening to give 2-hydroxyethyl phosphoramides 12 and 17, respectively. These intermediates rapidly cyclized to an oxazaphospholidine ring structure 13 or 18, with the subsequent loss of dimethylamine or aziridine. Analysis of ongoing hydrolysis showed

Jerry B. Stokes; Charles W. Woods; Alexej B. Borkovec

1981-01-01

446

Radiolysis of sulfuric acid, sulfuric acid monohydrate, and sulfuric acid tetrahydrate and its relevance to Europa  

Microsoft Academic Search

We report laboratory studies on the 0.8MeV proton irradiation of ices composed of sulfuric acid (H2SO4), sulfuric acid monohydrate (H2SO4·H2O), and sulfuric acid tetrahydrate (H2SO4·4H2O) between 10 and 180K. Using infrared spectroscopy, we identify the main radiation products as H2O, SO2, (S2O3)x, H3O+, HSO4-, and SO42-. At high radiation doses, we find that H2SO4 molecules are destroyed completely and that

M. J. Loeffler; R. L. Hudson; M. H. Moore; R. W. Carlson

2011-01-01

447

Digestion and absorption of polyunsaturated fatty acids  

E-print Network

bring to light the esterification step, particularly the integration of polyunsatura- ted fatty acids. polyunsaturated fatty acid / digestion / absorption pathway / enterocyte esterification / intesti- nal lipoprotein

Boyer, Edmond

448

Molecular structure of phenyl- and phenoxyacetic acids - spectroscopic and theoretical study  

NASA Astrophysics Data System (ADS)

The FT-IR, FT-Raman and 1H and 13C NMR spectra were recorded for phenyl- and phenoxyacetic acids in comparison with benzoic acid molecule. The density functional hybrid method (B3LYP/6-311++G**) was used to calculate optimized geometrical structures of studied compounds. The atomic charges were calculated by NBO (natural bond orbital) methods. Aromaticity indices, dipole moments and energies as well as the wavenumbers and intensities of IR spectra were calculated. The chemical shifts in NMR spectra using the gauge independent atomic orbital (GIAO) method were also analyzed. The theoretical parameters were compared to experimental characteristic of phenyl- and phenoxyacetic acids. The study of HOMO, LUMO and NBO analyses have been used to elucidate charge transfer within the molecule of title compounds. Molecular electrostatic potential (MEP) was also calculated.

Samsonowicz, M.

2014-01-01

449

Acidic extracellular microenvironment and cancer.  

PubMed

Acidic extracellular pH is a major feature of tumor tissue, extracellular acidification being primarily considered to be due to lactate secretion from anaerobic glycolysis. Clinicopathological evidence shows that transporters and pumps contribute to H+ secretion, such as the Na+/H+ exchanger, the H+-lactate co-transporter, monocarboxylate transporters, and the proton pump (H+-ATPase); these may also be associated with tumor metastasis. An acidic extracellular pH not only activates secreted lysosomal enzymes that have an optimal pH in the acidic range, but induces the expression of certain genes of pro-metastatic factors through an intracellular signaling cascade that is different from hypoxia. In addition to lactate, CO2 from the pentose phosphate pathway is an alternative source of acidity, showing that hypoxia and extracellular acidity are, while being independent from each other, deeply associated with the cellular microenvironment. In this article, the importance of an acidic extracellular pH as a microenvironmental factor participating in tumor progression is reviewed. PMID:24004445

Kato, Yasumasa; Ozawa, Shigeyuki; Miyamoto, Chihiro; Maehata, Yojiro; Suzuki, Atsuko; Maeda, Toyonobu; Baba, Yuh

2013-01-01

450

Acidic extracellular microenvironment and cancer  

PubMed Central

Acidic extracellular pH is a major feature of tumor tissue, extracellular acidification being primarily considered to be due to lactate secretion from anaerobic glycolysis. Clinicopathological evidence shows that transporters and pumps contribute to H+ secretion, such as the Na+/H+ exchanger, the H+-lactate co-transporter, monocarboxylate transporters, and the proton pump (H+-ATPase); these may also be associated with tumor metastasis. An acidic extracellular pH not only activates secreted lysosomal enzymes that have an optimal pH in the acidic range, but induces the expression of certain genes of pro-metastatic factors through an intracellular signaling cascade that is different from hypoxia. In addition to lactate, CO2 from the pentose phosphate pathway is an alternative source of acidity, showing that hypoxia and extracellular acidity are, while being independent from each other, deeply associated with the cellular microenvironment. In this article, the importance of an acidic extracellular pH as a microenvironmental factor participating in tumor progression is reviewed. PMID:24004445

2013-01-01

451

Magnesium and arachidonic acid metabolism.  

PubMed

The arachidonic acid content of plasma lipoproteins is altered during dietary magnesium deficiency, although the tissue arachidonic acid content seems to be unchanged. The primary event triggering these changes is probably the loss of extracellular Mg2+, as it is not clear whether dietary magnesium deficiency produces loss of intracellular Mg2+. In the isolated rabbit heart, in vitro perfusion conditions which produce loss of intracellular Mg2+ also result in disturbances of arachidonic acid metabolism. The metabolism of exogenous arachidonic acid to prostaglandins is increased without changing the Km or Vmax of cyclo-oxygenase. The incorporation of arachidonic acid into tissue phospholipids is significantly reduced, although the incorporation of oleate, stearate, and linolenate is either increased or unchanged. These data indicate that the activity of the enzymes (CoA synthetases and acyl transferases) which mediate arachidonate incorporation is reduced during Mg2+ depletion. Since protein-kinase-C-mediated phosphorylation of both CoA synthetase and acyl transferase reduces their activity, and since protein kinase C has an Mg2+ binding site, it is possible to speculate that loss of intracellular Mg2+ may lead to the activation of protein kinase C, with the consequent reduction of arachidonic acid reacylation enzyme activity. PMID:8274364

Weis, M T; Saunders, C

1993-06-01

452

Molecular Structure of Oxalic acid  

NSDL National Science Digital Library

Oxalic acid is an odorless, colorless powder or granular solid. It is used as a scouring agent in textiles for finishing, stripping, cleaning, and as a bleaching agent for stain removal. Oxalic acid is also used as a rust remover as well as a grease and wax removing agent in metal cleaning. It is also used to clean and sterilize equipment, slso as a purifying agent in the pharmaceutical industry, in the waste water treatment industry and is also used to remove calcium from water. Oxalic acid is found in many plants and in many vegetables, for example sorrel, spinach and rhubarb, usually as its calcium or potassium salts. Oxalic acid is produced commercially by nitric acid oxidation of starch. It also can be made by fusing sawdust (or other forms of cellulose) with a mixture of sodium hydroxide and potassium hydroxide. Oxalic acid may be released to the environment in tobacco smoke, automobile exhaust, rendering, in waste streams from pulp bleaching, and by photochemical oxidations of anthropogenic compounds during long range transport.

2004-11-10

453

A Study of the Acid Properties of Structurally and Compositionally Different Heteropoly Acids in Acetic Acid  

Microsoft Academic Search

The acid properties of heteropoly acids of the following three structure types were studied by conductometry in acetic acid: Keggin (H3PW12O40, H3PMo12O40, H4SiW12O40, H3PW11ThO39; and H5PW11XO40, where X(IV) = Ti or Zr), Dawson (a-H6P2W18O62and a-H6P2Mo18O62), and H6P2W21O71(H2O)3. These compounds are electrolytes that dissociate in only the first step of this solvent. The thermodynamic dissociation constants of the heteropoly acids were

M. N. Timofeeva; M. M. Matrosova; G. M. Maksimov; V. A. Likholobov

2001-01-01

454

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

455

Bile acids: regulation of apoptosis by ursodeoxycholic acid  

PubMed Central

Bile acids are a group of molecular species of acidic steroids with peculiar physical-chemical and biological characteristics. At high concentrations they become toxic to mammalian cells, and their presence is pertinent in the pathogenesis of several liver diseases and colon cancer. Bile acid cytoxicity has been related to membrane damage, but also to nondetergent effects, such as oxidative stress and apoptosis. Strikingly, hydrophilic ursodeoxycholic acid (UDCA), and its taurine-conjugated form (TUDCA), show profound cytoprotective properties. Indeed, these molecules have been described as potent inhibitors of classic pathways of apoptosis, although their precise mode of action remains to be clarified. UDCA, originally used for cholesterol gallstone dissolution, is currently considered the first choice therapy for several forms of cholestatic syndromes. However, the beneficial effects of both UDCA and TUDCA have been tested in other experimental pathological conditions with deregulated levels of apoptosis, including neurological disorders, such as Alzheimer's, Parkinson's, and Huntington's diseases. Here, we review the role of bile acids in modulating the apoptosis process, emphasizing the anti-apoptotic effects of UDCA and TUDCA, as well as their potential use as novel and alternate therapeutic agents for the treatment of apoptosis-related diseases. PMID:19417220

Amaral, Joana D.; Viana, Ricardo J. S.; Ramalho, Rita M.; Steer, Clifford J.; Rodrigues, Cecilia M. P.

2009-01-01

456

Fatty Acids, Antibiotic Resistance, and Deoxyribonucleic Acid Homology Groups of Bradyrhizobiurn japonicum  

Microsoft Academic Search

The fatty acid compositions and multiple antibiotic resistance patterns of 32 strains of Bradyrhizobium japonicum correlated with two major deoxyribonucleic acid homology groups. In group I, the fatty acid composition was 1.3% 16:l cis9 acid, 3.6% 16:lC acid, 8.8% 16:O acid, 1.2% 19:0 cyclopropane acid, and 81.2% 18:l acid. Group I1 contained 0.5% 16:lC acid, 11.1% 16:O acid, 0.8% 17:O

L. D. KUYKENDALL; M. A. ROY; J. J. O'NEILL

457

Kinetic and safety assessment for salicylic acid nitration by nitric acid/acetic acid system.  

PubMed

The nitration process of salicylic acid for the production of the important intermediate 5-nitrosalicylic acid is studied from thermokinetic and safety points of view. Investigations carried out by considering, as process deviations, the loss of the thermal control point out the possibility of runaway phenomena due to the occurrence of polynitration reactions. Isothermal experiments are carried out in various conditions to assess the involved reaction network and reaction kinetics. PMID:16343755

Andreozzi, R; Caprio, V; Di Somma, I; Sanchirico, R

2006-06-30

458

Dietary Eicosapentaenoic Acid and Docosahexaenoic Acid Are More Effective than Alpha-Linolenic Acid in Improving Insulin Sensitivity in Rats  

Microsoft Academic Search

In the present study, we investigated whether long-term administration of high dose of ?-linolenic acid (ALA) is able to mimic the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) or a mixture of both with respect to insulin sensitivity in male Wistar rats. Furthermore, we intended to test whether these n–3 polyunsaturated fatty acids reveal differential effects on glucose

Gaby Andersen; Kerstin Harnack; Helmut F. Erbersdobler; Veronika Somoza

2008-01-01

459

Cellular bicarbonate protects rat duodenal mucosa from acid-induced injury  

PubMed Central

Secretion of bicarbonate from epithelial cells is considered to be the primary mechanism by which the duodenal mucosa is protected from acid-related injury. Against this view is the finding that patients with cystic fibrosis, who have impaired duodenal bicarbonate secretion, are paradoxically protected from developing duodenal ulcers. Therefore, we hypothesized that epithelial cell intracellular pH regulation, rather than secreted extracellular bicarbonate, was the principal means by which duodenal epithelial cells are protected from acidification and injury. Using a novel in vivo microscopic method, we have measured bicarbonate secretion and epithelial cell intracellular pH (pHi), and we have followed cell injury in the presence of the anion transport inhibitor DIDS and the Cl– channel inhibitor, 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). DIDS and NPPB abolished the increase of duodenal bicarbonate secretion following luminal acid perfusion. DIDS decreased basal pHi, whereas NPPB increased pHi; DIDS further decreased pHi during acid challenge and abolished the pHi overshoot over baseline observed after acid challenge, whereas NPPB attenuated the fall of pHi and exaggerated the overshoot. Finally, acid-induced epithelial injury was enhanced by DIDS and decreased by NPPB. The results support the role of intracellular bicarbonate in the protection of duodenal epithelial cells from luminal gastric acid. PMID:11748264

Akiba, Yasutada; Furukawa, Osamu; Guth, Paul H.; Engel, Eli; Nastaskin, Igor; Sassani, Pejvak; Dukkipatis, Ramanath; Pushkin, Alexander; Kurtz, Ira; Kaunitz, Jonathan D.

2001-01-01

460

Gallic Acid, Ellagic Acid and Pyrogallol Reaction with Metallic Iron  

NASA Astrophysics Data System (ADS)

The reaction between gallic acid, ellagic acid and pyrogallol with metallic iron was studied using infrared and Mössbauer spectroscopy. Most hydrolysable tannins with interesting anticorrosive or inhibition properties are structurally related to these compounds, thus they may be used as models for the study of hydrolysable tannins and related polyphenols. The interaction was followed up to 3 months. Results indicated two different behaviors. At polyphenol concentrations higher than 1% iron converts to sparingly soluble and amorphous ferric (and ferrous) polyphenolate complexes. At lower concentrations (0.1%), the hydrolysis reactions are dominant, resulting in the formation of oxyhydroxides, which can be further reduced to compounds like magnetite by the polyphenols.

Jaén, J. A.; González, L.; Vargas, A.; Olave, G.

2003-06-01