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1

Crystal structure and luminescence property of ternary terbium p-aminobenzoic acid complexes with different second ligands  

E-print Network

Crystal structure and luminescence property of ternary terbium p-aminobenzoic acid complexes; revised 21 January 2005; accepted 24 January 2005 Abstract Ternary terbium complexes with p on the crystal structure and luminescence property of the ternary terbium p-aminobenzoic acid complexes

Gao, Song

2

N-Benzoyl-L-tyrosyl-p-aminobenzoic acid hydrolase beta (human meprinbeta). A 13-amino-acid sequence is required for proteolyticprocessing and subsequent secretion.  

PubMed

N-Benzoyl-L-tyrosyl-p-aminobenzoic acid hydrolase or human meprin (PPH) is a brush-border membrane enzyme of small intestinal epithelial cells. It is a type I integral membrane protein composed of two disulphide-bridged subunits (alpha and beta). PPH and its homologous counterparts in rodents belong to the astacin family of zinc-metalloendopeptidases. Although the amino-acid sequence of the beta subunits is 80-90% identical in these three species, processing is different. Expression of PPHbeta in simian virus 40-transformed African green monkey kidney cells (COS-1) and Madin Darby canine kidney (MDCK) cells results in its cell surface localization and secretion, whereas mouse meprinbeta is only found at the plasma membrane. To investigate proteolytic processing of PPHbeta and to identify the cleavage site, different C-terminal domains of wild-type PPHbeta were exchanged with the homologous domains of mouse meprinbeta. We identified a 13-amino-acid sequence (QIQLTPAPSVQDL) necessary for cleavage and subsequent secretion of PPHbeta. Using brefeldin A, the site of processing was identified as being after passage through the Golgi compartment. Proteolytic processing of PPHbeta thus provides a means for secretion of alphabeta heterodimers. PMID:10215852

Pischitzis, A; Hahn, D; Leuenberger, B; Sterchi, E E

1999-04-01

3

In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved  

E-print Network

In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved, and approved March 18, 2008 (received for review December 21, 2007) p-aminobenzoate N-oxygenase (AurF) from-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF

Zhao, Huimin

4

Interaction of P-aminobenzoic acid with normal and sickel erythrocyte membrane: photoaffinity labelling of the binding sites  

SciTech Connect

Electron microscopic studies revealed that P-Amino benzoic acid (PABA) could prevent eichinocytosis of red cells in vitro. Equilibrium binding studies with right side out membrane vesicles (ROV) revealed a similar number of binding sites (1.2-1.4 ..mu..mol/mg) and Kd (1.4-1.6 mM) values for both normal and sickle cell membranes. /sup 14/C-Azide analogue of PABA was synthesized as a photoaffinity label to probe its sites of interaction on the erythrocyte membranes. Competitive binding studies of PABA with its azide indicated that both the compounds share common binding sites on the membrane surface since a 20 fold excess of azide inhibited PABA binding in a linear fashion. The azide was covalently incorporated into the membrane components only upon irradiation (52-35% of the label found in the proteins and the rest in lipids). Electrophoretic analysis of photolabelled ROV revealed that the azide interacts chiefly with Band 3 protein. PABA inhibited both high and low affinity calcium (Ca) binding sites situated on either surface of the membrane in a non-competitive manner; however, Ca binding stimulated by Mg-ATP was not affected. Ca transport into inside out vesicles was inhibited by PABA; but it did not affect the calcium ATP-ase activity. The authors studies suggest that the mechanism of action of PABA is mediated by its interaction with Band 3 protein (anion channel), calcium channel and calcium binding sites of erythrocyte membrane.

Premachandra, B.R.

1986-03-05

5

In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved in aureothin biosynthesis  

Microsoft Academic Search

p-aminobenzoate N-oxygenase (AurF) from Streptomyces thioluteus catalyzes the formation of unusual polyketide synthase starter unit p-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF is a metalloenzyme, but its native enzymatic activity has not been demonstrated in vitro, and its catalytic mechanism is unclear. In addition, the nature of the cofactor remains a controversy. Here,

Yoo Seong Choi; Houjin Zhang; Joseph S. Brunzelle; Satish K. Nair; Huimin Zhao

2008-01-01

6

In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved in aureothin biosynthesis.  

PubMed

p-Aminobenzoate N-oxygenase (AurF) from Streptomyces thioluteus catalyzes the formation of unusual polyketide synthase starter unit p-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF is a metalloenzyme, but its native enzymatic activity has not been demonstrated in vitro, and its catalytic mechanism is unclear. In addition, the nature of the cofactor remains a controversy. Here, we report the in vitro reconstitution of the AurF enzyme activity, the crystal structure of AurF in the oxidized state, and the cocrystal structure of AurF with its product pNBA. Our combined biochemical and structural analysis unequivocally indicates that AurF is a non-heme di-iron monooxygenase that catalyzes sequential oxidation of aminoarenes to nitroarenes via hydroxylamine and nitroso intermediates. PMID:18458342

Choi, Yoo Seong; Zhang, Houjin; Brunzelle, Joseph S; Nair, Satish K; Zhao, Huimin

2008-05-13

7

In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved in aureothin biosynthesis  

PubMed Central

p-aminobenzoate N-oxygenase (AurF) from Streptomyces thioluteus catalyzes the formation of unusual polyketide synthase starter unit p-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF is a metalloenzyme, but its native enzymatic activity has not been demonstrated in vitro, and its catalytic mechanism is unclear. In addition, the nature of the cofactor remains a controversy. Here, we report the in vitro reconstitution of the AurF enzyme activity, the crystal structure of AurF in the oxidized state, and the cocrystal structure of AurF with its product pNBA. Our combined biochemical and structural analysis unequivocally indicates that AurF is a non-heme di-iron monooxygenase that catalyzes sequential oxidation of aminoarenes to nitroarenes via hydroxylamine and nitroso intermediates. PMID:18458342

Choi, Yoo Seong; Zhang, Houjin; Brunzelle, Joseph S.; Nair, Satish K.; Zhao, Huimin

2008-01-01

8

BIOCHEMICAL AND GENETIC CHARACTERIZATION OF AN EARLY STEP IN A NOVEL PATHWAY FOR THE BIOSYNTHESIS OF AROMATIC AMINO ACIDS AND P-AMINOBENZOIC ACID IN THE ARCHAEON METHANOCOCCUS MARIPALUDIS  

EPA Science Inventory

Methanococcus maripaludis is a strictly anaerobic, methane-producing archaeon and facultative autotroph capable of biosynthesizing all the amino acids and vitamins required for growth. In this work, the novel 6-deoxy-5-ketofructose-1-phosphate (DKFP) pathway for the biosynthesis ...

9

Production of p-Aminobenzoic Acid by the Tubercle Bacillus  

Microsoft Academic Search

MANY workers have claimed that the common sulphanilamides in high concentrations may modify the course of experimental tuberculosis in animals. Much better results have been obtained, however, with the diaminodiphenyl-sulphone and some of its derivatives, for example, promin and diasone. The same applies to promizole, an analogous compound, which is a diaminophenyl-thiazole-sulphone. These sulphones have also shown a certain effect

Torsten Ekstrand; Bertil Sjögren

1945-01-01

10

SYNTHESIS AND CHARACTERIZATION OF METAL COMPLEXES OF P,P?DI[3-(TRIMETHYLSILYL)-1PROPYL] METHYLENEDIPHOSPHONIC ACID  

Microsoft Academic Search

The silicon-substituted diphosphonic acid P,P?-di[3-(trimethyl-silyl)-1-propyl] methylenediphosphonic acid, H2DTMSP-[MDP], reacts with metal nitrates in methanol to form complexes M2(DTMSP[MDP])3 for M?Fe, Eu and Yb and M(DTMSP[MDP])2 for M?Th. The sodium salt, Na2-(DTMSP[MDP]), forms upon neutralization of H2DTMSP-[MDP] with NaOH. The calcium salt, Ca(DTMSP[MDP]), forms upon addition of the aqueous metal nitrate to an equivalent amount of the neutralized ligand in methanol.

Daniel R. McAlister; Albert W. Herlinger; John R. Ferraro; Mark L. Dietz

2002-01-01

11

Inhibition of p-aminobenzoate and folate syntheses in plants and apicomplexan parasites by natural product rubreserine.  

PubMed

Glutamine amidotransferase/aminodeoxychorismate synthase (GAT-ADCS) is a bifunctional enzyme involved in the synthesis of p-aminobenzoate, a central component part of folate cofactors. GAT-ADCS is found in eukaryotic organisms autonomous for folate biosynthesis, such as plants or parasites of the phylum Apicomplexa. Based on an automated screening to search for new inhibitors of folate biosynthesis, we found that rubreserine was able to inhibit the glutamine amidotransferase activity of the plant GAT-ADCS with an apparent IC(50) of about 8 ?M. The growth rates of Arabidopsis thaliana, Toxoplasma gondii, and Plasmodium falciparum were inhibited by rubreserine with respective IC(50) values of 65, 20, and 1 ?M. The correlation between folate biosynthesis and growth inhibition was studied with Arabidopsis and Toxoplasma. In both organisms, the folate content was decreased by 40-50% in the presence of rubreserine. In both organisms, the addition of p-aminobenzoate or 5-formyltetrahydrofolate in the external medium restored the growth for inhibitor concentrations up to the IC(50) value, indicating that, within this range of concentrations, rubreserine was specific for folate biosynthesis. Rubreserine appeared to be more efficient than sulfonamides, antifolate drugs known to inhibit the invasion and proliferation of T. gondii in human fibroblasts. Altogether, these results validate the use of the bifunctional GAT-ADCS as an efficient drug target in eukaryotic cells and indicate that the chemical structure of rubreserine presents interesting anti-parasitic (toxoplasmosis, malaria) potential. PMID:22577137

Camara, Djeneb; Bisanz, Cordelia; Barette, Caroline; Van Daele, Jeroen; Human, Esmare; Barnard, Bernice; Van der Straeten, Dominique; Stove, Christophe P; Lambert, Willy E; Douce, Roland; Maréchal, Eric; Birkholtz, Lyn-Marie; Cesbron-Delauw, Marie-France; Dumas, Renaud; Rébeillé, Fabrice

2012-06-22

12

Inhibition of O2 Consumption Resistant to Cyanide and Its Development by N-Propyl Gallate and Salicylhydroxamic Acid 1  

PubMed Central

Kinetics of inhibition of cyanide-insensitive O2 uptake by n-propyl gallate (PG) and salicylhydroxamic acid (SHAM) were determined in fresh slices from ethylene-treated tubers of Solanum tuberosum `Norchip' and with mitochondria and lipoxygenase (EC 1.13.11.12) isolated from these tubers. PG and SHAM appeared to be inhibiting at identical sites in mitochondria but at disparate sites in slices. The apparent KI for SHAM was similar in mitochondria and slices. However, the apparent KI for PG in mitochondria was about 40-fold lower than the KI for PG inhibition of lipoxygenase activity. The amount of lipoxygenase associated with mitochondria increased when tubers were treated with ethylene. PG, but not SHAM, inhibited aging-induced development of cyanide-insensitive respiration. The latter two phenomena are in accord with the hypothesis that lipid metabolism is required for the development of the alternative pathway. PMID:16662588

Janes, Harry W.; Wiest, Steven C.

1982-01-01

13

Fabrication of calcium phosphate-calcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid.  

PubMed

In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate (CSD, CaSO4 x 2H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid phase (20, 40 wt%). In each groups, the HPMC percentage was 0, 2, and 4 wt%. An increase in compressive strength due to changes in morphology was confirmed by scanning electron microscopy images. A good conversion rate of HAp at 20% citric acid was observed in the XRD profiles. In addition, HPMC was not obviously affected by apatite formation. However, both HPMC and citric acid increased the compressive strength of IBS. The maximum compressive strength for IBS was with 40% citric acid and 4% HPMC after 14 days of incubation in 100% humidity at 37 degrees C. PMID:20333539

Thai, Van Viet; Lee, Byong-Taek

2010-06-01

14

Corrosion inhibition behavior of propyl phosphonic acid-Zn2+ system for carbon steel in aqueous solution  

NASA Astrophysics Data System (ADS)

The effectiveness of propyl phosphonic acid (PPA) as a corrosion inhibitor in association with a bivalent cation like Zn2+ has been studied. An eco-friendly inhibitor in controlling corrosion of carbon steel in neutral aqueous medium in the absence and presence of Zn2+ has been evaluated by gravimetric method. Impedance studies of the metal/solution interface indicated that the surface film is highly protective against the corrosion of carbon steel in the aqueous environment. Potentiodynamic polarization studies showed that the inhibitor is a mixed inhibitor. X-ray photoelectron spectroscopic analysis (XPS) of the protective film exhibited the presence of the elements viz., iron, phosphorus, oxygen, carbon and zinc. The chemical shifts in the binding energies of these elements inferred that the surface film is composed of oxides/hydroxides of iron(III), Zn(OH)2 and [Fe(II)/(III)-Zn(II)-PPA] complex. Further, the surface analysis techniques viz., FT-IR, AFM and SEM studies confirm the formation of an adsorbed protective film on the carbon steel surface. Based on all these results, a plausible mechanism of corrosion inhibition is proposed.

Prabakaran, M.; Venkatesh, M.; Ramesh, S.; Periasamy, V.

2013-07-01

15

Synthesis and characterization of metal complexes of P, P{sup prime}DI[3-(trimethylsilyl)-1-propyl] methylenediphosphonic acid{double_dagger}  

Microsoft Academic Search

The silicon-substituted diphosphonic acid P,P'-di[3-(trimethyl-silyl)-1-propyl] methylenediphosphonic acid, H2DTMSP-[MDP], reacts with metal nitrates in methanol to form complexes M2(DTMSP[MDP])3 for M=Fe, Eu and Yb and M(DTMSP[MDP])2 for M=Th. The sodium salt, Na2-(DTMSP[MDP]), forms upon neutralization of H2DTMSP-[MDP] with NaOH. The calcium salt, Ca(DTMSP[MDP]), forms upon addition of the aqueous metal nitrate to an equivalent amount of the neutralized ligand in methanol.

D. R. McAlister; A. W. Herlinger; J. R. Ferraro; M. L. Dietz

2002-01-01

16

Linkage and Branch Analysis of High-Mannose Oligosaccharides Using Closed-Ring Labeling of 8-Aminopyrene-1,3,6-Trisulfonate and P-Aminobenzoic Ethyl Ester and Negative Ion Trap Mass Spectrometry  

NASA Astrophysics Data System (ADS)

A strategy based on negative ion electrospray ionization tandem mass spectrometry and closed-ring labeling with both 8-aminopyrene-1,3,6-trisulfonate (APTS) and p-aminobenzoic acid ethyl ester (ABEE) was developed for linkage and branch determination of high-mannose oligosaccharides. X-type cross-ring fragment ions obtained from APTS-labeled oligosaccharides by charge remote fragmentation provided information on linkages near the non-reducing terminus. In contrast, A-type cross-ring fragment ions observed from ABEE-labeled oligosaccharides yielded information on linkages near the reducing terminus. This complementary information provided by APTS- and ABEE-labeled oligosaccharides was utilized to delineate the structures of the high-mannose oligosaccharides. As a demonstration of this approach, the linkages and branches of high-mannose oligosaccharides Man5GlcNAc2, Man6GlcNAc2, Man8GlcNAc2, and Man9GlcNAc2 cleaved from the ribonuclease B were assigned from MS2 spectra of ABEE- and APTS-labeled derivatives.

Chen, Shu-Ting; Her, Guor-Rong

2012-08-01

17

SWELLING OF PEATS IN LIQUID METHYL, TETRAMETHYLENE AND PROPYL SULFOXIDES AND IN LIQUID PROPYL SULFONE  

EPA Science Inventory

The interactions of methyl, tetramethylene, and propyl sulfoxides and propyl sulfone during sorption onto four de-waxed, acid-form peats have been studied by means of swelling measurements. The results for sulfoxides are displayed as het-eromolecular sorption isotherms, which plo...

18

Amino acid analysis in physiological samples by GC-MS with propyl chloroformate derivatization and iTRAQ-LC-MS/MS.  

PubMed

Two mass spectrometry-based methods for the quantitative analysis of free amino acids are described. The first method uses propyl chloroformate/propanol derivatization and gas chromatography-quadrupole mass spectrometry (GC-qMS) analysis in single-ion monitoring mode. Derivatization is carried out directly in aqueous samples, thereby allowing automation of the entire procedure, including addition of reagents, extraction, and injection into the GC-MS. The method delivers the quantification of 26 amino acids. The isobaric tagging for relative and absolute quantification (iTRAQ) method employs the labeling of amino acids with isobaric iTRAQ tags. The tags contain two different cleavable reporter ions, one for the sample and one for the standard, which are detected by fragmentation in a tandem mass spectrometer. Reversed-phase liquid chromatography of the labeled amino acids is performed prior to mass spectrometric analysis to separate isobaric amino acids. The commercial iTRAQ kit allows for the analysis of 42 physiological amino acids with a respective isotope-labeled standard for each of these 42 amino acids. PMID:22125145

Dettmer, Katja; Stevens, Axel P; Fagerer, Stephan R; Kaspar, Hannelore; Oefner, Peter J

2012-01-01

19

FT-IR SOLUTION SPECTRA OF PROPYL SULFIDE, PROPYL SULFOXIDE, AND PROPYL SULFONE  

EPA Science Inventory

FT-IR spectra were obtained of 0.5% volumetric solutions of propyl sulfide, propyl sulfoxide, and propyl sulfone in hexane, CCl4, CS2, and CHCl3 to assist in the assignment of FT-IR-PAS spectra of propyl sulfoxide sorbed within the structure of several peats and onto cellulose. T...

20

FTIR SOLUTION SPECTRA OF PROPYL SULFIDE, PROPYL SULFOXIDE, AND PROPYL SULFONE  

EPA Science Inventory

FTIR spectra were obtained of 0.5% volumetric solutions of propyl sulfide, propyl sulfoxide and propyl sulfone in hexane, CC14, CS2, and CHCl3 to assist in the assignment of FTIR-PAS spectra of propyl sulfoxide sorbed within the structure of several peats and onto cellulose. he C...

21

Synthesis and characterization of metal complexes of P, P{sup prime}-DI[3-(trimethylsilyl)-1-propyl] methylenediphosphonic acid{double_dagger}.  

SciTech Connect

The silicon-substituted diphosphonic acid P,P'-di[3-(trimethyl-silyl)-1-propyl] methylenediphosphonic acid, H2DTMSP-[MDP], reacts with metal nitrates in methanol to form complexes M2(DTMSP[MDP])3 for M=Fe, Eu and Yb and M(DTMSP[MDP])2 for M=Th. The sodium salt, Na2-(DTMSP[MDP]), forms upon neutralization of H2DTMSP-[MDP] with NaOH. The calcium salt, Ca(DTMSP[MDP]), forms upon addition of the aqueous metal nitrate to an equivalent amount of the neutralized ligand in methanol. Elemental analysis, infrared spectroscopy and magnetic susceptibility measurements were used to characterize the compounds. Frequency shifts in the asymmetric and symmetric POO- stretching bands of the Fe, Eu, Yb and Th compounds indicate symmetrical coordination of the phosphonate groups through chelate and/or bridging interactions. The frequency difference between these stretching bands becomes smaller as the ionic potential (e/r) of the metal ion increases.

McAlister, D. R.; Herlinger, A. W.; Ferraro, J. R.; Dietz, M. L.; Chemistry; Loyola Univ.

2002-02-01

22

Water-soluble N-[(2-hydroxy-3-trimethylammonium)propyl]chitosan chloride as a nucleic acids vector for cell transfection.  

PubMed

To endow the cationic polysaccharides with solubility in the whole pH-range without loss of functionality of the amino groups, different chitosan samples were treated with glycidyltrimethylammonium chloride. Each modified unit of the exhaustively alkylated quaternized chitosan (QCht) contained both quaternary and secondary amino groups. The intercalated dye displacement assay and ?-potential measurements implied stability of QCht polyplexes at physiological conditions and protonation of the secondary amino groups in slightly acidic media which is favorable for transfection according to proton sponge mechanism. The cytotoxicity and transfection efficacy increased with the chain lengthening. Nevertheless, the longest chains of QCht, 250 kDa were less toxic than PEI for COS-1 cells and revealed comparable and even significantly higher transfection activity of siRNA and plasmid DNA, respectively. Thus, highly polymerized QCht (250 kDa) provided the highest level of the plasmid DNA transfection being 5 and 80 times more active than QCht (100 kDa) and QCht (50 kDa), respectively, and 4-fold more effective than PEI, 25 kDa. The established influence of QCht molecular weight on toxicity and transfection efficacy allows elaborating polysaccharide vectors that possess rational balance of these characteristics. PMID:24750918

Faizuloev, Evgeny; Marova, Anna; Nikonova, Alexandra; Volkova, Irina; Gorshkova, Marina; Izumrudov, Vladimir

2012-08-01

23

Conversion of nitrogen dioxide, nitric acid, and n-propyl nitrate to nitric oxide by gold-catalyzed reduction with carbon monoxide  

Microsoft Academic Search

A new technique is described for the real-time, quantitative conversion of several XNOâ compounds to NO, where X denotes a radical group. The technique utilizes the reduction of these compounds by CO at heated gold catalyst to yield NO. The NO product was detected by a sensitive chemiluminescence detector. The technique was demonstrated to convert NOâ, HNOâ, and n-propyl nitrate

Mark J. Bollinger; Robert E. Sievers; David W. Fahey; Frederick C. Fehsenfeld

1983-01-01

24

Kinetics of the transformation of n-propyl gallate and structural analogs in the perfused rat liver  

SciTech Connect

n-Propyl gallate and its analogs are used in foods and other products to prevent oxidation. In the liver the compound exerts several harmful effects, especially gluconeogenesis inhibition. The mode of transport and distribution of n-propyl gallate and its kinetics of biotransformation have not yet been investigated. To fill this gap the transformation, transport and distribution of n-propyl gallate and two analogs were investigated in the rat liver. Isolated perfused rat liver was used. n-Propyl gallate, methyl gallate, n-octyl gallate and transformation products were quantified by high pressure-liquid chromatography coupled to fluorescence detection. The interactions of n-propyl gallate and analogs with the liver presented three main characteristics: (1) the hydrolytic release of gallic acid from n-propyl gallate and methyl gallate was very fast compared with the subsequent transformations of the gallic acid moiety; (2) transport of the esters was very fast and flow-limited in contrast to the slow and barrier-limited transport of gallic acid; (3) the apparent distribution volume of n-propyl gallate, but probably also of methyl gallate and n-octyl gallate, greatly exceeded the water space in the liver, contrary to the gallic acid space which is smaller than the water space. It can be concluded that at low portal concentrations (< 50 ?M) the gallic acid esters are 100% extracted during a single passage through the liver, releasing mainly gallic acid into the systemic circulation. For the latter a considerable time is required until complete biotransformation. The exposure of the liver to the esters, however, is quite prolonged due to extensive intracellular binding. - Highlights: • The liver binds very strongly n-propyl gallate and releases basically gallic acid. • n-propyl gallate and analogs undergo concentrative flow-limited distribution. • Gallic acid undergoes barrier-limited distribution and is slowly transformed. • The long residence time of n-propyl gallate and analogs increases toxicity.

Eler, Gabrielle Jacklin; Santos, Israel Souza; Giaretta de Moraes, Amarilis; Mito, Márcio Shigueaki; Comar, Jurandir Fernando; Peralta, Rosane Marina; Bracht, Adelar, E-mail: adebracht@uol.com.br

2013-11-15

25

Determination of efficacy of fingermark enhancement reagents; the use of propyl chloroformate for the derivatization of fingerprint amino acids extracted from paper.  

PubMed

The analysis of the constituents of fingerprints has been described numerous times, mainly with the purpose of determining the aging effect on fingerprints or showing the differences between donors or groups of donors. In this paper we describe the use of derivatized amino acids to determine the efficacy of the visualization reagents 1,8-diazafluoren-9-one (DFO) and ninhydrin. At present certain conditions are used for the application of these reagents, as determined by trial-and-error investigations, to the effect on fingerprints. The recovery of amino acids from a porous surface can be used as a measure for the efficacy of a visualization agent. In this paper we describe a method for the determination of the amount of amino acid left after reaction with well known fingerprint visualization reagents. This will allow a more scientific approach to method development for fingermark enhancement techniques. Furthermore, investigations on the influence of the concentration of fingermark amino acids, the order of application of and exposure time to reagents and the influence of age of the amino acids were carried out. These studies have resulted in a broader understanding of the mechanism involved in visualization of fingermarks using DFO and ninhydrin. PMID:23937938

Mink, Tineke; Voorhaar, Annelies; Stoel, Reinoud; de Puit, Marcel

2013-09-01

26

21 CFR 573.880 - Normal propyl alcohol.  

Code of Federal Regulations, 2010 CFR

... 6 2010-04-01 2010-04-01 false Normal propyl alcohol. 573.880 Section 573.880...ANIMALS Food Additive Listing § 573.880 Normal propyl alcohol. Normal propyl alcohol may be safely used in feeds and...

2010-04-01

27

21 CFR 573.880 - Normal propyl alcohol.  

Code of Federal Regulations, 2014 CFR

... 6 2014-04-01 2014-04-01 false Normal propyl alcohol. 573.880 Section 573.880...ANIMALS Food Additive Listing § 573.880 Normal propyl alcohol. Normal propyl alcohol may be safely used in feeds and...

2014-04-01

28

21 CFR 573.880 - Normal propyl alcohol.  

Code of Federal Regulations, 2012 CFR

... 6 2012-04-01 2012-04-01 false Normal propyl alcohol. 573.880 Section 573.880...ANIMALS Food Additive Listing § 573.880 Normal propyl alcohol. Normal propyl alcohol may be safely used in feeds and...

2012-04-01

29

21 CFR 573.880 - Normal propyl alcohol.  

Code of Federal Regulations, 2011 CFR

... 6 2011-04-01 2011-04-01 false Normal propyl alcohol. 573.880 Section 573.880...ANIMALS Food Additive Listing § 573.880 Normal propyl alcohol. Normal propyl alcohol may be safely used in feeds and...

2011-04-01

30

21 CFR 573.880 - Normal propyl alcohol.  

Code of Federal Regulations, 2013 CFR

... 6 2013-04-01 2013-04-01 false Normal propyl alcohol. 573.880 Section 573.880...ANIMALS Food Additive Listing § 573.880 Normal propyl alcohol. Normal propyl alcohol may be safely used in feeds and...

2013-04-01

31

Room-temperature luminescence of the volatile compounds, 1- and 2-naphthol, and other compounds, 5,6-benzoquinoline, 4-phenylphenol, phenanthrene, triphenylene, and p-aminobenzoic acid, adsorbed on filter paper treated with salts and cyclodextrins  

SciTech Connect

1- and 2-Naphthol are known to volatilize upon heating along with solvents such as ethanol and water. Filter paper, treated with salts and cyclodextrins, was shown to be capable of trapping these volatile phosphors efficiently on filter paper and permitting strong luminescence signals to be observed. Filter paper samples treated with and without cyclodextrins were compared on the basis of their ability to induce room-temperature fluorescence and phosphorescence from adsorbed naphthols and five other organic compounds. Also, the effect of heavy-atom salt, NaBr, on the phosphorescence intensities of phosphors adsorbed on the filter paper surfaces was studied.

Ramasamy, S.M.; Hurtubise, R.J. (Univ. of Wyoming, Laramie, WY (United States))

1989-01-01

32

Interaction of single-walled carbon nanotubes with poly(propyl ether imine) dendrimers  

NASA Astrophysics Data System (ADS)

We study the complexation of nontoxic, native poly(propyl ether imine) dendrimers with single-walled carbon nanotubes (SWNTs). The interaction was monitored by measuring the quenching of inherent fluorescence of the dendrimer. The dendrimer-nanotube binding also resulted in the increased electrical resistance of the hole doped SWNT, due to charge-transfer interaction between dendrimer and nanotube. This charge-transfer interaction was further corroborated by observing a shift in frequency of the tangential Raman modes of SWNT. We also report the effect of acidic and neutral pH conditions on the binding affinities. Experimental studies were supplemented by all atom molecular dynamics simulations to provide a microscopic picture of the dendrimer-nanotube complex. The complexation was achieved through charge transfer and hydrophobic interactions, aided by multitude of oxygen, nitrogen, and n-propyl moieties of the dendrimer.

Jayamurugan, G.; Vasu, K. S.; Rajesh, Y. B. R. D.; Kumar, S.; Vasumathi, V.; Maiti, P. K.; Sood, A. K.; Jayaraman, N.

2011-03-01

33

Detection of a branched alkyl molecule in the interstellar medium: iso-propyl cyanide.  

PubMed

The largest noncyclic molecules detected in the interstellar medium (ISM) are organic with a straight-chain carbon backbone. We report an interstellar detection of a branched alkyl molecule, iso-propyl cyanide (i-C3H7CN), with an abundance 0.4 times that of its straight-chain structural isomer. This detection suggests that branched carbon-chain molecules may be generally abundant in the ISM. Our astrochemical model indicates that both isomers are produced within or upon dust grain ice mantles through the addition of molecular radicals, albeit via differing reaction pathways. The production of iso-propyl cyanide appears to require the addition of a functional group to a nonterminal carbon in the chain. Its detection therefore bodes well for the presence in the ISM of amino acids, for which such side-chain structure is a key characteristic. PMID:25258074

Belloche, Arnaud; Garrod, Robin T; Müller, Holger S P; Menten, Karl M

2014-09-26

34

Interaction of single-walled carbon nanotubes with poly(propyl ether imine) dendrimers  

SciTech Connect

We study the complexation of nontoxic, native poly(propyl ether imine) dendrimers with single-walled carbon nanotubes (SWNTs). The interaction was monitored by measuring the quenching of inherent fluorescence of the dendrimer. The dendrimer-nanotube binding also resulted in the increased electrical resistance of the hole doped SWNT, due to charge-transfer interaction between dendrimer and nanotube. This charge-transfer interaction was further corroborated by observing a shift in frequency of the tangential Raman modes of SWNT. We also report the effect of acidic and neutral pH conditions on the binding affinities. Experimental studies were supplemented by all atom molecular dynamics simulations to provide a microscopic picture of the dendrimer-nanotube complex. The complexation was achieved through charge transfer and hydrophobic interactions, aided by multitude of oxygen, nitrogen, and n-propyl moieties of the dendrimer.

Jayamurugan, G.; Rajesh, Y. B. R. D.; Jayaraman, N. [Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012 (India); Vasu, K. S.; Kumar, S.; Sood, A. K. [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Vasumathi, V.; Maiti, P. K. [Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

2011-03-14

35

Pathologically activated neuroprotection via uncompetitive blockade of N-methyl-D-aspartate receptors with fast off-rate by novel multifunctional dimer bis(propyl)-cognitin.  

PubMed

Uncompetitive N-methyl-d-aspartate (NMDA) receptor antagonists with fast off-rate (UFO) may represent promising drug candidates for various neurodegenerative disorders. In this study, we report that bis(propyl)-cognitin, a novel dimeric acetylcholinesterase inhibitor and gamma-aminobutyric acid subtype A receptor antagonist, is such an antagonist of NMDA receptors. In cultured rat hippocampal neurons, we demonstrated that bis(propyl)-cognitin voltage-dependently, selectively, and moderately inhibited NMDA-activated currents. The inhibitory effects of bis(propyl)-cognitin increased with the rise in NMDA and glycine concentrations. Kinetics analysis showed that the inhibition was of fast onset and offset with an off-rate time constant of 1.9 s. Molecular docking simulations showed moderate hydrophobic interaction between bis(propyl)-cognitin and the MK-801 binding region in the ion channel pore of the NMDA receptor. Bis(propyl)-cognitin was further found to compete with [(3)H]MK-801 with a K(i) value of 0.27 mum, and the mutation of NR1(N616R) significantly reduced its inhibitory potency. Under glutamate-mediated pathological conditions, bis(propyl)-cognitin, in contrast to bis(heptyl)-cognitin, prevented excitotoxicity with increasing effectiveness against escalating levels of glutamate and much more effectively protected against middle cerebral artery occlusion-induced brain damage than did memantine. More interestingly, under NMDA receptor-mediated physiological conditions, bis(propyl)-cognitin enhanced long-term potentiation in hippocampal slices, whereas MK-801 reduced and memantine did not alter this process. These results suggest that bis(propyl)-cognitin is a UFO antagonist of NMDA receptors with moderate affinity, which may provide a pathologically activated therapy for various neurodegenerative disorders associated with NMDA receptor dysregulation. PMID:20404346

Luo, Jialie; Li, Wenming; Zhao, Yuming; Fu, Hongjun; Ma, Dik-Lung; Tang, Jing; Li, Chaoying; Peoples, Robert W; Li, Fushun; Wang, Qinwen; Huang, Pingbo; Xia, Jun; Pang, Yuanping; Han, Yifan

2010-06-25

36

The reaction of hydroperoxy-propyl radicals with molecular oxygen  

SciTech Connect

Addition of hydroperoxy-alkyl radicals to molecular oxygen leads to chain branching in autoignition and engine knock, and in low temperature oxidation of paraffins. Rate constants and product channels for reaction of hydroperoxy-propyl radicals with O{sub 2} are estimated using thermodynamic properties, bimolecular quantum Kassel analysis and transition state theory. Thermochemistry of relevant molecules and radicals is estimated using group additivity and bond dissociation groups for radicals. Results show that rates of the hydroperoxy-propyl radical addition to O{sub 2} are near their high pressure limits at {ge} 1 atm. Main products at 1--15 atm are stabilization, reverse reaction to hydroperoxy-propyl + O{sub 2} and alkyl carbonyl + OH. Reactions of the stabilized adducts, dissociation rates and product channels are estimated using unimolecular quantum Kassel analysis, because stabilization is the most important hydroperoxy-propyl radical + O{sub 2} product channel. Below 700 K, the stabilized peroxy adducts react primarily to hydroperoxy-carbonyl + OH, products which lead to chain branching. Above 700K, the stabilized peroxy adducts react primarily to hydroperoxy-propyl radical + O{sub 2}, initial reactants, which inhibits the overall oxidation. This switchover in channels correlates well observed negative temperature coefficient behavior for propane oxidation. Rate expressions for reaction of each of the three hydroperoxy-alkyl isomers with O{sub 2} and for dissociation of the associated stabilized adducts are calculated for a series of pressures at 300--2100K.

Bozzelli, J.W. [New Jersey Inst. of Tech., Newark, NJ (United States). Dept. of Chemistry and Chemical Engineering; Pitz, W.J. [Lawrence Livermore National Lab., CA (United States)

1993-12-03

37

Crystal structure of 3-amino-1-propyl­pyridinium bromide  

PubMed Central

The title mol­ecular salt, C8H13N2 +·Br?, crystallizes with two independent 3-amino­pyridinium cations and two bromide anions in the asymmetric unit (Z? = 2). In the pyridine ring, the N atom is alkyl­ated by a propyl group. The dihedral angle between the mean planes of the pyridinium ring and the propyl group is 84.84?(2)° in cation A, whereas the corresponding angle is 89.23?(2)° in cation B. In the crystal, the anions and cations are linked via N—H?Br and C—H?Br hydrogen bonds, forming chains propagating along [100]. PMID:25552997

Venkatesan, P.; Rajakannan, V.; Thamotharan, S.

2014-01-01

38

40 CFR 721.10176 - Amides, peanut-oil, N-[3-(dimethylamino)propyl].  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Amides, peanut-oil, N-[3-(dimethylamino)propyl...Substances § 721.10176 Amides, peanut-oil, N-[3-(dimethylamino)propyl...chemical substance identified as amides, peanut-oil,...

2013-07-01

39

40 CFR 721.10176 - Amides, peanut-oil, N-[3-(dimethylamino)propyl].  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Amides, peanut-oil, N-[3-(dimethylamino)propyl...Substances § 721.10176 Amides, peanut-oil, N-[3-(dimethylamino)propyl...chemical substance identified as amides, peanut-oil,...

2012-07-01

40

40 CFR 721.10176 - Amides, peanut-oil, N-[3-(dimethylamino)propyl].  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Amides, peanut-oil, N-[3-(dimethylamino)propyl...Substances § 721.10176 Amides, peanut-oil, N-[3-(dimethylamino)propyl...chemical substance identified as amides, peanut-oil,...

2011-07-01

41

40 CFR 721.10176 - Amides, peanut-oil, N-[3-(dimethylamino)propyl].  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Amides, peanut-oil, N-[3-(dimethylamino)propyl...Substances § 721.10176 Amides, peanut-oil, N-[3-(dimethylamino)propyl...chemical substance identified as amides, peanut-oil,...

2014-07-01

42

40 CFR 721.10176 - Amides, peanut-oil, N-[3-(dimethylamino)propyl].  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Amides, peanut-oil, N-[3-(dimethylamino)propyl...Substances § 721.10176 Amides, peanut-oil, N-[3-(dimethylamino)propyl...chemical substance identified as amides, peanut-oil,...

2010-07-01

43

Dextran Carrier Macromolecules for Colon-specific Delivery of 5-Aminosalicylic Acid  

PubMed Central

Present manuscript describes the sustained and targeted delivery of 5-aminosalicylic acid to the distal ileum and proximal colon, using dextran (40 kDa) as a carrier for targeting 5-aminosalicylic acid at the colonic site by attaching p-aminobenzoic acid and benzoic acid as linkers. Prepared conjugate were characterized by UV, HPLC, FT-IR, and 1H NMR. The degree of substitution was estimated by complete hydrolysis of conjugates in borate buffer and in vitro hydrolysis study of conjugates was performed in different biological media. It was observed that 5-aminosalicylic acid alone have produced high incidence of gastric ulcer with high ulcer index whereas lower ulcer index was found for the dextran conjugates of 5-aminosalicylic acid. The release pattern of conjugates in 3% w/v rat caecal content was confirmed the colon specificity of 5-aminosalicylic acid conjugates. PMID:24082343

Shrivastava, P. K.; Shrivastava, A.; Sinha, S. K.; Shrivastava, S. K.

2013-01-01

44

DOI: 10.1002/cbic.200600136 A New Class of Arylamine  

E-print Network

DOI: 10.1002/cbic.200600136 A New Class of Arylamine Oxygenases: Evidence that p- Aminobenzoate N-Oxygenase metabolic reactions,[1,2] aminopyrrolnitrin oxy- genase (PrnD)[2] and p-aminobenzoate oxygenase (AurF)[3 as in other laboratories,[1,5] p-aminobenzoic acid (pABA) conversion to p- nitrobenzoic acid (p

Zhao, Huimin

45

Conformers and photochemistry of propyl nitrites: a matrix isolation study.  

PubMed

The infrared spectra of both constitutional isomers (n and i) of propyl nitrite have been recorded in an Ar matrix. Conformational analysis and assignments of the vibrational transitions have been carried out on the basis of quantum chemical calculations. Assignment of spectral lines to different conformers was also aided experimentally, by utilizing the different rate of photodecomposition of the conformers, as well as by employing conformational cooling using a supersonic jet as the inlet source for matrix deposition. The rate of photodecomposition is primarily determined by the steric alignment of the nitrite group, whereas jet cooling affects mainly the conformation of the alkyl tail. On the basis of these experimental observations and computational predictions two to three conformers of isopropyl nitrite and eight conformers of n-propyl nitrite were identified. After broadband ultraviolet-visible (UV-vis) photolysis of isopropyl nitrite in the matrix, HNO, acetone, HNO.acetone complex, acetaldehyde, and nitrosomethane were identified as the main products. Furthermore, in a small amount, NO and possibly the isopropoxy radical were also present in the matrix. Photolysis of n-propyl nitrite yielded HNO, propanal, and their 1:1 complex as the main products together with a small amount of NO and cis-1-nitrosopropanol. PMID:17228893

Matyus, Edit; Magyarfalvi, Gabor; Tarczay, György

2007-01-25

46

40 CFR 180.362 - Hexakis (2-methyl-2-phenyl-propyl)distannoxane; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2-methyl-2-phenyl-propyl)distannoxane; tolerances for residues. 180.362 Section 180.362...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances §...

2010-07-01

47

Effects of phenolic propyl esters on the oxidative stability of refined sunflower oil.  

PubMed

The oxidative stability of refined sunflower oil in the presence and in the absence of propyl caffeate (PC), propyl hydrocaffeate (PHC), propyl ferulate (PF), and propyl isoferulate (PI) has been evaluated according to the Rancimat method. The antioxidant activity of the phenolic derivatives was compared with that obtained with native [alpha-tocopherol (alpha-TOH)] and synthetic [propyl gallate (PG)] antioxidants. The results allow the establishment of a decreasing order of antioxidant power: PG > PHC > PC > alpha-TOH > PI > PF. The oxidative stability was improved neither by the addition of PF nor by a supplement of alpha-TOH. Moreover, a positive antioxidant effect was obtained for PC that was placed between those of alpha-TOH and PG. The antioxidant activity of PHC was higher than that of its analogue (PC). A dose-dependent effect was observed for PG, PHC, and PC. A chain-breaking mechanism was proposed for the antioxidant activity of propyl phenolic esters because the same ranking order of efficacy was obtained for their antiradical activities evaluated by using the 2,2-diphenyl-1-picrylhydrazyl radical method. PMID:11513692

Silva, F A; Borges, F; Ferreira, M A

2001-08-01

48

Metabolism and cytotoxicity of propyl gallate in isolated rat hepatocytes: effects of a thiol reductant and an esterase inhibitor.  

PubMed

The relationship between the metabolism and the cytotoxic effects of propyl gallate (PG) has been studied in freshly isolated rat hepatocytes. Addition of PG (0.5-2.0 mM) to the hepatocytes elicited concentration-dependent cell death, accompanied by decreases in intracellular ATP, adenine nucleotide pools, glutathione, and protein thiols. The rapid loss of ATP preceded the onset of cell death. PG in the hepatocyte suspensions was converted to gallic acid, 4-O-methyl-gallic acid, and other minor products over time. In addition, PG was converted to a dimer [dipropyl-4,4',5,5',6,6'-hexahydroxydiphenate (PG-dimer)] and ellagic acid via autooxidation. In comparisons of the toxic effects of PG and its metabolites at concentrations of 2 mM, the parent compound PG was the most toxic. Pretreatment of hepatocytes with diazinon (100 microM), an esterase inhibitor, enhanced PG-induced cytotoxicity. This was accompanied by delay of PG loss and inhibition of gallic acid formation. The cytotoxicity of PG was also enhanced by addition of the thiol reductant dithiothreitol (4 mM), although intracellular levels of glutathione and protein thiols were maintained during the incubation period. Dithiothreitol did not affect the hydrolysis of PG to gallic acid by esterases but did delay the conversion of PG and prevented the formation of PG-dimer. In isolated hepatic mitochondria, PG elicited a concentration-dependent increase in the rate of state 4 oxygen consumption, indicating an uncoupling effect. In contrast, PG-dimer inhibited the rate of state 3 oxygen consumption. Based on the respiratory control index, the order of potency for impairment of mitochondria was PG > PG-dimer > gallic acid = 4-O-methyl-gallic acid = ellagic acid - propyl alcohol. These results indicate (a) that PG-induced hepatotoxicity is mediated by the parent compound and not its metabolites, (b) that toxicity is associated with ATP depletion apparently independently of cellular thiol depletion, and (c) that mitochondria may represent critical targets of PG-induced cytotoxicity. PMID:7746268

Nakagawa, Y; Nakajima, K; Tayama, S; Moldéus, P

1995-05-01

49

Mechanism of photooxidation of folic acid sensitized by unconjugated pterins.  

PubMed

Folic acid, or pteroyl-l-glutamic acid (PteGlu), is a precursor of coenzymes involved in the metabolism of nucleotides and amino acids. PteGlu is composed of three moieties: a 6-methylpterin (Mep) residue, a p-aminobenzoic acid (PABA) residue, and a glutamic acid (Glu) residue. Accumulated evidence indicates that photolysis of PteGlu leads to increased risk of several pathologies. Thus, a study of PteGlu photodegradation can have significant ramifications. When an air-equilibrated aqueous solution of PteGlu is exposed to UV-A radiation, the rate of the degradation increases with irradiation time. The mechanism involved in this "auto-photo-catalytic" effect was investigated in aqueous solutions using a variety of tools. Whereas PteGlu is photostable under anaerobic conditions, it is converted into 6-formylpterin (Fop) and p-aminobenzoyl-l-glutamic acid (PABA-Glu) in the presence of oxygen. As the reaction proceeds and enough Fop accumulates in the solution, a photosensitized electron-transfer process starts, where Fop photoinduces the oxidation of PteGlu to Fop, and H(2)O(2) is formed. This process also takes place with other pterins as photosensitizers. The results are discussed with the context of previous mechanisms for processes photosensitized by pterins, and their biological implications are evaluated. PMID:20922252

Dántola, M Laura; Denofrio, M Paula; Zurbano, Beatriz; Gimenez, Carlos S; Ogilby, Peter R; Lorente, Carolina; Thomas, Andrés H

2010-12-01

50

Photodissociation dynamics of the 2-propyl radical, C{sub 3}H{sub 7}  

SciTech Connect

The photodissociation of 2-propyl leading to propene+H was investigated with nanosecond time resolution. A supersonic beam of isolated 2-propyl radicals was produced by pyrolysis of 2-bromopopane. The kinetic energy release of the H-atom photofragment was monitored as a function of excitation wavelength by photofragment Doppler spectroscopy via the Lyman-{alpha} transition. The loss of hydrogen atoms after excitation proceeds in {alpha} position to the radical center with a rate constant of 5.8x10{sup 7} s{sup -1} at 254 nm. Approximately 20% of the excess energy is deposited as translation in the H-atom photofragment. In contrast 1-propyl does not lose H atoms to a significant extent. The experimental results are compared to simple Rice-Ramsperger-Kassel-Marcus calculations. The possible reaction pathways are examined in hybrid density functional theory calculations.

Noller, Bastian; Fischer, Ingo [Institute of Physical Chemistry, University of Wuerzburg, Am Hubland D-97074 Wuerzburg (Germany)

2007-04-14

51

Oral treatment of polioencephalomalacia and subclinical thiamine deficiency with thiamine propyl disulphide and thiamine hydrochloride.  

PubMed

Thiaminase type I production by Bacillus thiaminolyticus and activity in vitro were repressed by the primary substate thiamine and by thiamine monophosphate and thiamine propyl disulphide. At thiamine concentrations of 300-3000 mumol/l production of active enzyme by B. thiaminolyticus, and activity of purified enzyme, were totally repressed. Growth of B. thiaminolyticus was inhibited by thiamine propyl disulphide at 3000 mumol/l. Activity of purified thiaminase was lost when incubated with ruminal fluid from healthy thiaminase free sheep. Enzyme activity was also lost when exposed to mildly alkaline conditions but was stimulated and stabilized against heat denaturation if treated with dithiothreitol. Thiaminase activities in the ruminal fluids of cases of ovine polioencephalomalacia were repressed within 2 h of oral administration of thiamine propyl disulphide. Blood pyruvate levels and transketolase activities were restored to normal following treatment. Treated animals recovered clinically and were returned to pasture. PMID:3806781

Thomas, K W

1986-12-01

52

Mechanisms for the Expulsion of Propene from Ionized Propyl Phenyl Ethers in the Gas Phase  

E-print Network

analysis (which considers competition among four pathways). These two analyses lead to different complexes that randomize hydrogen within the propyl cation. Only 1% of ionized 1c fragments via site-protonated cyclopropanes. Correction for these alternative pathways leads to the conclusion that the primary isotope effect

Morton, Thomas Hellman

53

40 CFR 721.10192 - Amides, coco, N-[3-(dibutylamino)propyl], acrylates.  

Code of Federal Regulations, 2010 CFR

. (1) The chemical substance identified as amides, coco, N-[3-(dibutylamino)propyl], acrylates (PMN P-06-263, Chemical A; CAS No. 851545-09-0) is subject to reporting under this section for the significant new uses described in paragraph (a)(2) of this section. (2) The significant new uses...

2010-07-01

54

Studies on the Food Additive Propyl Gallate: Synthesis, Structural Characterization, and Evaluation of the Antioxidant Activity  

ERIC Educational Resources Information Center

Antioxidants are additives largely used in industry for delaying, retarding, or preventing the development of oxidative deterioration. Propyl gallate (E310) is a phenolic antioxidant extensively used in the food, cosmetics, and pharmaceutical industries. A series of lab experiments have been developed to teach students about the importance and…

Garrido, Jorge; Garrido, E. Manuela; Borges, Fernanda

2012-01-01

55

Synthesis, spectra and crystal structure of 2-(?[3-(methyl?3-[(2-hydroxybenzylidene)amino]propyl? amino)propyl]imino?methyl)phenol copper(II) complex  

NASA Astrophysics Data System (ADS)

A copper(II) complex, [Cu(salenN3], [salenN3H2=2-({[3-(methyl{3-[(2-hydroxybenzylidene)amino]propyl}amino)propyl]imino}methyl)phenol] was synthesized and characterized by elemental analyses, FTIR spectra and single crystal X-ray diffraction. The complex crystallizes in the monoclinic space group P21/ c with a=6.877(3), b=14.109(6), c=20.106(8) Å, ?=92.231(14)°, V=1949.5(14) Å 3. The salen ligand loses two phenolic hydrogens being a dianion and coordinates to the copper(II) ion as a pentadentate ligand through its two O and three N atoms. The copper(II) complex is five-coordinate, lying between perfect square pyramidal and trigonal-bipyramidal extremes. Use of the structural index parameter ( ?) for five coordinate metal complexes indicated that the copper(II) complex exhibits a grater tendency toward trigonal-based-pyramidal geometry ( ?>0.5). The individual molecules in the crystal are held together by C-H⋯? and H⋯H interactions. The IR and electronic spectra of the complex were discussed in detail.

Yilmaz, Veysel T.; Degirmencioglu, Ismail; Andac, Omer; Karabocek, Serdar; Slawin, Alexandra M. Z.

2003-06-01

56

Methyl propyl carbonate: A promising single solvent for Li-ion battery electrolytes  

Microsoft Academic Search

Methyl propyl carbonate (MPC) solutions containing Li salts can be used as a single-solvent electrolyte with addition of ethylene carbonate (EC). Graphite electrodes can be cycled at high reversible capacity in MPC solutions containing LiPFâ and LiAsFâ. The use of acyclic, unsymmetric alkyl carbonate solvents, such as ethyl methyl carbonate (EMC) and MPC in Li-ion based electrolytes, increases the stability

Yair Ein-Eli; S. F. McDevitt; D. Aurbach; B. Markovsky; A. Schechter

1997-01-01

57

Diffusion and Catalytic Cracking of 1,3,5 Tri-iso-propyl-benzene in FCC Catalysts  

E-print Network

1 Diffusion and Catalytic Cracking of 1,3,5 Tri-iso- propyl-benzene in FCC Catalysts S.Al-Khattaf1-iso-propyl-benzene and two FCC catalysts with different crystal sizes (0.4-m and 0.9-m diameter). The experiments are modeled and to produce more environmentally friendly products. The currently available 60-m commercial FCC catalysts

Al-Khattaf, Sulaiman

58

THE USE OF FATTY ACID-ESTERS TO ENHANCE FREE ACID SOPHOROLIPID SYNTHESIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate, Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid sophorolipids (SLs). Fed-batch fermentat...

59

Reaction of the 2-hydroxy-2-propyl radical with acrylate type molecules in aqueous solution: Radical addition or electron transfer  

NASA Astrophysics Data System (ADS)

The reaction of 2-hydroxy-2-propyl (IP) radical with 12 acrylate type monomers in aqueous solutions was investigated by means of pulse radiolysis: the molecular structure effects and the mechanisms were evaluated. Radicals were generated either in the reaction of hydrated electron with acetone and subsequent protonation or in the H abstraction reaction by OH radicals from i-propanol. IP radical reacts with acrylamides and acrylic acid esters in radical addition reaction of the type: (CH 3) 2(OH)C rad + CH 2dbnd CH-C(O)R ? (CH 3) 2(OH)C-CH 2-C rad H-C(O)R with rate coefficients between 3.2 × 10 7 and 1.9 × 10 8 mol -1 dm 3 s -1. Rate coefficients of the reaction with maleic acid (neutral), dimethyl- and diethyl maleate are between 1.3 × 10 8 and 4.7 × 10 8 mol -1 dm 3 s -1. The values for dimethyl- and diethyl fumarate are ca. one order of magnitude higher. However with maleates and fumarates there is also a few percent contribution from the electron transfer reaction of the type (CH 3) 2(OH)C rad + ROOC-CH dbnd CH-COOR + H 2O ? ROOC-CH dbnd CH-C rad O -OR + (CH 3) 2CO + H 3O +. In neutral solutions and at pH ˜3 and ˜9, the same rate coefficients were measured. However, in dialkyl maleate and -fumarate solutions between pH 9.5 and 10.5, a base catalyzed decomposition of the IP radical adduct was observed forming electron adduct: ROOC-C((CH 3) 2(OH)C)H-C rad H-COOR + OH - ? ROOC-CH dbnd CH-C rad O -OR + (CH 3) 2CO + H 2O. Molecular structure effects were evaluated using log k- ?p and log k-LUMO plots.

Wojnárovits, László; Takács, Erzsébet; Emmi, Salvatore S.

2006-09-01

60

rac-2-Phenyl-1-[(2,4,6-triiso­propyl­benzene)­sulfon­yl]aziridine  

PubMed Central

In the title compound, C23H31NO2S, the geometry of the triiso­propyl­phenyl group is slightly distorted, with elongated C—C bonds at the ipso-C atom, and an S atom which deviates from the benzene ring plane by 0.228?(2)?Å. This distortion is caused by the bulky substituents and, in comparison, an unbent geometry is observed in N-toluene­sulfonyl­aziridine [Zhu et al. (2006 ?). Acta Cryst. E62, o1507–o1508]. ?–? inter­actions between adjacent benzene rings [centroid–centroid distance = 3.7928?(11)?Å] and are observed. PMID:24764875

Golz, Christopher; Preut, Hans; Strohmann, Carsten

2014-01-01

61

{(E)-2-[3-(Dimethyl­ammonio)propyl­iminometh­yl]phenolato}diiodidozinc(II)  

PubMed Central

The title complex, [ZnI2(C12H18N2O)], is a mononuclear zinc(II) compound derived from the zwitterionic form of the Schiff base (E)-2-[(3-dimethyl­amino­propyl­imino)meth­yl]phenol. The ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand, and by two iodide ions in a tetra­hedral coordination geometry. In the crystal structure, mol­ecules are linked through inter­molecular N—H?O hydrogen bonds, forming chains running along the b axis. PMID:21203068

Zhu, Xue-Wen; Yang, Xu-Zhao

2008-01-01

62

Determination of rotary diffusivity of poly(n-propyl isocyanate) by molecular dynamics  

NASA Astrophysics Data System (ADS)

The rotational dynamics of a nondilute solution of the rodlike polymer poly(n-propyl isocyanate) (PPIC) has been studied on an atomistic model by means of a large-scale classical molecular dynamics investigation. The rotary diffusivity of PPIC in toluene solution has been determined from the Einsteinian diffusion regime of the end-to-end vector on the surface of the unit sphere and has been found to be Dr=10.5×105(±2.7)s-1, which falls in the range of the experimental data available. A comparison of molecular dynamics predictions with theoretical and perturbation expansion predictions has also been performed.

Laso, M.; Jimeno, N.; Muneta, L. M.; Müller, M.

2006-12-01

63

Expression alterations of genes on both neuronal and glial development in rats after developmental exposure to 6-propyl-2-thiouracil.  

PubMed

The present study was performed to determine target gene profiles associated with pathological mechanisms of developmental neurotoxicity. For this purpose, we selected a rat developmental hypothyroidism model because thyroid hormones play an essential role in both neuronal and glial development. Region-specific global gene expression analysis was performed at postnatal day (PND) 21 on four brain regions representing different structures and functions, i.e., the cerebral cortex, corpus callosum, dentate gyrus and cerebellar vermis of rats exposed to 6-propyl-2-thiouracil in the drinking water at 3 and 10ppm from gestational day 6 to PND 21. Expression changes of gene clusters of neuron differentiation and development, cell migration, synaptic function, and axonogenesis were detected in all four regions. Characteristically, gene expression profiles suggestive of affection of ephrin signaling and glutamate transmission were obtained in multiple brain regions. Gene clusters suggestive of suppression of myelination and glial development were specifically detected in the corpus callosum and cerebral cortex. Immunohistochemically, immature astrocytes immunoreactive for vimentin and glial fibrillary acidic protein were increased, and oligodendrocytes immunoreactive for oligodendrocyte lineage transcription factor 2 were decreased in the corpus callosum. Immunoreactive intensity of myelin basic protein was also decreased in the corpus callosum and cerebral cortex. The hippocampal dentate gyrus showed downregulation of Ptgs2, which is related to synaptic activity and neurogenesis, as well as a decrease of cyclooxygenase-2-immunoreactive granule cells, suggesting an impaired synaptic function related to neurogenesis. These results suggest that multifocal brain region-specific microarray analysis can determine the affection of neuronal or glial development. PMID:24780913

Shiraki, Ayako; Saito, Fumiyo; Akane, Hirotoshi; Takeyoshi, Masahiro; Imatanaka, Nobuya; Itahashi, Megu; Yoshida, Toshinori; Shibutani, Makoto

2014-08-01

64

Propyl-ended hemifluorinated surfactants: synthesis and self-assembling properties.  

PubMed

The advantages of using hemifluorinated surfactants as an efficient alternative to detergents for manipulating membrane proteins in aqueous solution have been demonstrated in recent reports. However, the large-scale synthesis of these surfactants is still considered as a major matter and has limited their use for biochemical purposes. We report herein the synthesis of a novel series of perfluorohexane-based surfactants endowed with a short propyl hydrocarbon tip and whose polar head size is modulated by the presence of two or three glucose moieties. The synthetic route is based on the radical addition of two alkenes onto the 1,6-diiodoperfluorohexane using AIBN as a radical initiator, affording the surfactants in satisfactory overall yields. The self-assembling properties of these hemifluorinated surfactants were studied by surface tension measurements, dynamic light scattering, as well as their behavior upon reversed-phase chromatography and were compared with those of their perfluorinated analogues. Our findings strongly suggest the predominant influence of the propyl tip on both adsorption and micellization phenomena as well as on the hydrophobic character of the surfactants, whereas as previously observed, the shorter ethyl tip does not greatly affect these properties when compared to the perfluorinated analogues. Moreover, all the surfactants reported here self-assemble into small and monodisperse aggregates, a feature of crucial importance for biochemistry applications. PMID:21384802

Abla, Maher; Durand, Grégory; Pucci, Bernard

2011-04-01

65

f3niB33n;^|Jlm. PMP Micro-Stabilized Rodent Liquid Diet  

E-print Network

,riboflavin,caldum pantothenate, nicotinic acid, choline chloride, pyridoxine hydrochloride, folic acid, inositol, p-aminobenzoic acid, biotin, calcium acetate, calcium phosphate, potassium phosphate, sodium phosphate, magnesium sulfate, sodium chloride, manganese sulfate, ferrous fijmarate, zinc chloride, cupric sulfate, chromium

Kleinfeld, David

66

40 CFR 721.9517 - Siloxanes and silicones, de-Me, 3-[4-[[[3-(dimethyl amino) propyl] amino]carbonyl]-2-oxo-1...  

Code of Federal Regulations, 2010 CFR

(1) The chemical substance identified as siloxanes and silicones, de-Me, 3-[4-[[[3-(dimethylamino) propyl]amino] carbonyl]-2-oxo-1-pyrrolidinyl]propyl Me (PMN P-97-332) is subject to reporting under this section for the significant new uses described in paragraph (a)(2) of this...

2010-07-01

67

40 CFR 180.1065 - 2-Amino-4,5-dihydro-6-methyl-4-propyl-s-triazolo(1,5-alpha)pyrimidin-5-one; exemption from the...  

Code of Federal Regulations, 2011 CFR

...5-dihydro-6-methyl-4-propyl-s-triazolo(1,5-alpha)pyrimidin-5-one; exemption from...5-dihydro-6-methyl-4-propyl-s-triazolo(1,5-alpha)pyrimidin-5-one; exemption from...5-dihydro-6-methyl-4-propyl-s-triazolo(1,5-alpha)pyrimidin-5-one is...

2011-07-01

68

40 CFR 180.1065 - 2-Amino-4,5-dihydro-6-methyl-4-propyl-s-triazolo(1,5-alpha)pyrimidin-5-one; exemption from the...  

Code of Federal Regulations, 2010 CFR

...5-dihydro-6-methyl-4-propyl-s-triazolo(1,5-alpha)pyrimidin-5-one; exemption from...5-dihydro-6-methyl-4-propyl-s-triazolo(1,5-alpha)pyrimidin-5-one; exemption from...5-dihydro-6-methyl-4-propyl-s-triazolo(1,5-alpha)pyrimidin-5-one is...

2010-07-01

69

Micellar and biochemical properties of a propyl-ended fluorinated surfactant designed for membrane-protein study.  

PubMed

Our goal is to design optimised fluorinated surfactants for handling membrane proteins in solution. We report herein the self-assembling and biochemical properties of a new hemifluorinated surfactant (H3F6H3DigluM) with a branched diglucosylated polar head group and an apolar tail consisting of a perfluorohexane core decorated with a hydrogenated propyl tip. For the sake of comparison, its fluorinated analogue without propyl tip (F6H3DigluM) was also studied. Isothermal titration calorimetry and surface tension showed that the addition of a propyl tip has a significant effect on the overall hydrophobicity of the surfactant, in contrast to the behaviour described when adding an ethyl tip to a fluorinated surfactant. From dynamic light scattering, analytical ultracentrifugation and small-angle X-ray scattering, both H3F6H3DigluM and F6H3DigluM self-assemble into small globular micelles of 5-7nm in diameter and have aggregation numbers of 62±8 and 46±2, respectively. Finally, H3F6H3DigluM was found to be the best fluorinated surfactant developed in our group to stabilise the model membrane protein bacteriorhodopsin (bR) in aqueous solution. This study demonstrates the suitability of this new propyl-ended fluorinated surfactant for biochemical and structural applications and confirms the superiority of hemifluorinated chains over fluorinated ones. PMID:25616252

Abla, Maher; Unger, Sebastian; Keller, Sandro; Bonneté, Françoise; Ebel, Christine; Pucci, Bernard; Breyton, Cécile; Durand, Grégory

2015-05-01

70

ESR dosimetry and radical kinetics of gamma-irradiated propyl gallate  

NASA Astrophysics Data System (ADS)

Propyl gallate (PG) is one of the most effective synthetic antioxidant. In the present work, the effects of gamma radiation on powder PG were investigated by Electron Spin Resonance (ESR) spectroscopy. The experimental spectra of irradiated PG were found to be consisted of two different overlapped spectra that originated for different radical species. Structural and kinetic features of the radicals which are responsible for experimental ESR spectrum were explored through the variations of the signal intensity with applied microwave power, variable sample temperature, and high-temperature annealing studies. Activation energies of the radical species were determined using the data derived from annealing studies. The dosimetric potential was also investigated in the range of 0.5-25.0 kGy. It was found that the G value of PG is about 0.35.

Bal, M. O.; Tuner, H.

2014-08-01

71

[Acute and subacute toxicity studies of tris (1,3-dichloro-2-propyl) phosphate on mice].  

PubMed

Slc/ddY mice (10 male, 10 female per group) were given a single p.o. intubation of tris (1,3-dichloro-2-propyl) phosphate (TDCPP) in olive oil and were observed for 14 days. LD50 values of male and female mice were 2.67 (2.52 approximately 2.83) and 2.25 2.25 (2.12 approximately 2.39) g/kg, respectively. The animals revealed ataxic gait, hyperactivity, and convulsion. Slc/ddY mice (12 male, 12 female er group) were administered diet containing 1.33, 0.42, 0.13, 0.04, and 0.01% of TDCPP for 3 months. Male and female mice of the 1.33% group showed emaciation, rough hair, and tremor; and all animals died within one month. Hematological studies showed slight anemia in males of the 0.42% group and females of the 0.42% and 0.13% groups. They also exhibited a tendency to increase ALP and GPT levels. The animals of the 0.42%, 0.13% and 0.04% groups exhibited tendency to increase liver weights and kidney weights in both sexes. Histopathologically, very slight focal necrosis was recognized in the liver in only 2 females of the 0.42% group. The NOEL under this condition is 0.01% in the diet of tris (1,3-dichloro-2-propyl) phosphate (male: 13.2 mg/kg/day, female: 15.3 mg/kg/day). PMID:2636931

Kamata, E; Naito, K; Nakaji, Y; Ogawa, Y; Suzuki, S; Kaneko, T; Takada, K; Kurokawa, Y; Tobe, M

1989-01-01

72

Stimulation of H+ Efflux and Inhibition of Photosynthesis by Esters of Carboxylic Acids 1  

PubMed Central

Suspensions of mechanically isolated Asparagus sprengeri Regel mesophyll cells were used to investigate the influence of various carboxyester compounds on rates of net H+ efflux in the dark or light and photosynthetic O2 production. Addition of 0.15 to 1.5 millimolar malathion, ?-naphthyl acetate, phenyl acetate, or p-nitrophenyl acetate stimulated H+ efflux and inhibited photosynthesis within 1 minute. In contrast, the more polar esters methyl acetoacetate or ethyl p-aminobenzoate had little or no effect on either of these two processes. A 0.15 millimolar concentration of ?-naphthylacetate stimulated the normal rate of H+ efflux, 0.77 nanomoles H+ per 106 cells per minute by 750% and inhibited photosynthesis by 100%. The four active carboxyester compounds also stimulated H+ efflux after the normal rate of H+ efflux was eliminated with 0.01 milligrams per milliliter oligomycin or 100% N2. Oligomycin reduced the ATP level by 70%. Incubation of cells with malathion, ?-naphthyl acetate, or p-nitrophenyl acetate resulted in the generation of the respective hydrolysis products ethanol, ?-naphthol, and p-nitrophenol. It is proposed that inhibition of photosynthesis and stimulation of H+ efflux result when nonpolar carboxyester compounds enter the cell and generate acidic carboxyl groups when hydrolyzed by esterase enzymes. PMID:16663308

Duhaime, Donna E.; Bown, Alan W.

1983-01-01

73

Design, Synthesis, Antibacterial Evaluation and Docking Study of Novel 2-Hydroxy-3-(nitroimidazolyl)-propyl-derived Quinolone.  

PubMed

A novel series of 2-hydroxy-3-(nitroimidazolyl)-propyl-derived quinolones 6a-o were synthesized and evaluated for their in vitro antibacterial activity. Most of the target compounds exhibited potent activity against Gram-positive strains. Among them, moxifloxacin analog 6n displayed the most potent activity against Gram-positive strains including S. epidermidis (MIC = 0.06 ?g/mL), MSSE (MIC = 0.125 ?g/mL), MRSE (MIC = 0.03 ?g/mL), S. aureus (MIC = 0.125 ?g/mL), MSSA (MIC = 0.125 ?g/mL), (MIC = 2 ?g/mL). Its activity against MRSA was eightfold more potent than reference drug gatifloxacin. Finally, docking study of the target compound 6n revealed that the binding model of quinolone nucleus was similar to that of gatifloxacin and the 2-hydroxy-3-(nitroimidazolyl)-propyl group formed two additional hydrogen bonds. PMID:25048811

Li, Qing; Xing, Junhao; Cheng, Haibo; Wang, Hui; Wang, Jing; Wang, Shuai; Zhou, Jinpei; Zhang, Huibin

2015-01-01

74

Spectrophotometry Determination of Atenolol via Hydroxamic acid Formation  

Microsoft Academic Search

A simple spectrophotometric method for the determination of atenolol by hydroxamic acid formation in dosage forms is described. Atenolol (2-p-hydroxy-3-isopropylaminopropoxy phenyl-acetamide) reacts with hydroxylamine hydrochloride in alkaline medium to give 2-p-hydroxy-3-iso-propyl amino-propoxyphenyl aceto hydroxamic acid, which forms a reddish violet coloured complex with Iron(III) in acidic medium having maximum absorbance at 510 nm, and molar absorbtivity 5.3 × 10 mol.cm

Y. K. Agrawal; K. Raman; S. Rajput; S. K. Menon

1992-01-01

75

Synthesis of novel poly{methyl-[3-(9-indolyl)propyl]siloxane}-based nonlinear optical polymers via postfunctionalization  

Microsoft Academic Search

A novel series of nonlinear optical (NLO) polysiloxanes with a high density of chromophore moieties based on poly{methyl-[3-(9-indolyl)propyl]siloxane} (PMIPS) were synthesized by a post functional strategy. First, PMIPS (P1) was prepared through hydrosilylation reaction, then P1 is partially formylated by the reaction between P1 and the reagents of dimethylformamide (DMF) and phosphorus oxychloride under the standard Vilsmeier reaction conditions, and

Zhen Li; Jianli Hua; Qianqian Li; Cheng Huang; Anjun Qin; Cheng Ye; Jingui Qin

2005-01-01

76

Indirect determination of thiamazole with the n -propyl alcohol-ammonium sulfate-H 2 O system by the extraction-flotation of CuSCN  

Microsoft Academic Search

In this paper, a new method for the determination of thiamazole by the extraction-flotation of CuSCN with n-propyl alcohol-ammonium sulfate-H2O system was described. The experiment indicated that in the presence of SCN?, Cu(II) was reduced to Cu(I) by thiamazole because of the formation of CuSCN. In the course of phase separation of n-propyl alcohol from water, the precipitated CuSCN remained

Q. Li; W. Zhao; G. Liu

2008-01-01

77

Lithiation and silylation reactions of 1,4-bis(1,1,1,3,3,3-hexafluoro-2-hydroxy-2-propyl)benzene  

Microsoft Academic Search

1,4-Bis(1,1,1,3,3,3-hexafluoro-2-hydroxy-2-propyl)benzene forms tri- and tetralithio derivatives which react readily with (CH3)3SiCl or (CH3)2SiCl2 to form the expected derivatives. Silicon is shown to be weakly coordinated to oxygen in 2,5-bis(trimethylsilyl)-1,4- bis(1,1,1,3,3,3-hexafluoro-2-hydroxy-2-propyl)benzene.

John W. Fitch; Patrick E. Cassidy; M. Jamil Ahmed

1996-01-01

78

Synthesis of Oligodeoxyribonucleotide Analogues by Use of Deoxyribonucleoside3?-yl O-bis(1,1,1,3,3,3-Hexafluoro-2Propyl) Phosphites as New Key Intermediates  

Microsoft Academic Search

The deoxyribonucleoside-3?-yl O-bis(1,1,1,3,3,3-hexafluoro-2-propyl) phosphite units (3) could be converted into the O-nucleosidyl phosphonate, O-2-cyanoethyl O-nucleosidyl phosphonate, and O-1,1,1,3,3,3-hexafluoro-2-propyl O-nucleosidyl phosphonothioate. Compound 3a was activated by methylimidazole to give the dithymidylate derivatives (8). The appropriately protected nucleosidyl phosphonates (3) were applied to the synthesis of oligodeoxyribonucleotides used as antisense oligonucleotides.

Hideo Hosaka; Yoshikazu Suzuki; Hiroyuki Nakamura; Hidenori Funakoshi; Hideki Nakashima; Naoki Yamamoto; Hiroshi Takaku

1992-01-01

79

Comparison of different amino acid derivatives and analysis of rat brain microdialysates by liquid chromatography tandem mass spectrometry.  

PubMed

The efficiencies of three derivatisation reagents that react with either the amine (9-fluorenylmethyl chloroformate (FMOC)) or the carboxylic acid group (butanol) of amino acid or with both types of functional groups (propyl chloroformate) were compared in the analysis of amino acids by liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS). Separation of 20 amino acids derivatised with these three reagents was studied on reversed-phase chromatography. Linearity, repeatability and limits of detection of the LC-ESI-MS/MS method were determined by analysing FMOC-, butanol- and propyl chloroformate-derivatised lysine, beta-aminobutyric acid, threonine and glutamic acid. The limits of detection for the derivatised amino acids (7.5-75fmol) were as much as 2-60 times lower than those of the corresponding underivatised molecules. The best linearity was observed for amino acids derivatised with propyl chloroformate or butanol (r(2)=0.996-0.999, range=100-8500nmolL(-1)). Propyl chloroformate was the best suited of the reagents tested for the analysis of amino acids with LC-MS/MS and was used for the analysis of amino acids in rat brain microdialysis samples. PMID:19166726

Uutela, Päivi; Ketola, Raimo A; Piepponen, Petteri; Kostiainen, Risto

2009-02-01

80

Infrared and Raman spectroscopic studies of tris-[3-(trimethoxysilyl)propyl] isocyanurate, its sol-gel process, and coating on aluminum and copper.  

PubMed

Tris-[3-(trimethoxysilyl)propyl] isocyanurate (TTPI) has been used as a precursor to prepare a sol using ethanol as the solvent under acidic conditions. The sol-gel was applied for the surface treatment of aluminum and copper. Infrared and Raman spectra have been recorded for pure TTPI and the TTPI sol, xerogel and TTPI sol-gel coated metals. From the vibrational spectra, TTPI is likely to have the C1 point group. Vibrational assignments are suggested based on group frequencies, the expected reactions in the sol-gel process and the vibrational studies of some related molecules. From the experimental infrared spectra of xerogels annealed at different temperatures and from the thermal-gravimetric analysis, it is found that the TTPI xerogel decomposes at around 450°C with silica being the major decomposition product. A cyclic voltammetric study of the metal electrodes coated with different concentrations of TTPI ranging from 5% to 42% (v/v) has shown that the films with high concentrations of sol would provide better corrosion protection for aluminum and copper. PMID:24866089

Li, Ying-Sing; Church, Jeffrey S; Woodhead, Andrea L; Vecchio, Nicolas E; Yang, Johnny

2014-11-11

81

Infrared and Raman spectroscopic studies of tris-[3-(trimethoxysilyl)propyl] isocyanurate, its sol-gel process, and coating on aluminum and copper  

NASA Astrophysics Data System (ADS)

Tris-[3-(trimethoxysilyl)propyl] isocyanurate (TTPI) has been used as a precursor to prepare a sol using ethanol as the solvent under acidic conditions. The sol-gel was applied for the surface treatment of aluminum and copper. Infrared and Raman spectra have been recorded for pure TTPI and the TTPI sol, xerogel and TTPI sol-gel coated metals. From the vibrational spectra, TTPI is likely to have the C1 point group. Vibrational assignments are suggested based on group frequencies, the expected reactions in the sol-gel process and the vibrational studies of some related molecules. From the experimental infrared spectra of xerogels annealed at different temperatures and from the thermal-gravimetric analysis, it is found that the TTPI xerogel decomposes at around 450 °C with silica being the major decomposition product. A cyclic voltammetric study of the metal electrodes coated with different concentrations of TTPI ranging from 5% to 42% (v/v) has shown that the films with high concentrations of sol would provide better corrosion protection for aluminum and copper.

Li, Ying-Sing; Church, Jeffrey S.; Woodhead, Andrea L.; Vecchio, Nicolas E.; Yang, Johnny

2014-11-01

82

Hydroxy propyl cellulose capped silver nanoparticles produced by simple dialysis process  

SciTech Connect

Silver (Ag) nanoparticles ({approx}6 nm) were synthesized using a novel dialysis process. Silver nitrate was used as a starting precursor, ethylene glycol as solvent and hydroxy propyl cellulose (HPC) introduced as a capping agent. Different batches of reaction mixtures were prepared with different concentrations of silver nitrate (AgNO{sub 3}). After the reduction and aging, these solutions were subjected to ultra-violet visible spectroscopy (UVS). Optimized solution, containing 250 mg AgNO{sub 3} revealed strong plasmon resonance peak at {approx}410 nm in the spectrum indicating good colloidal state of Ag nanoparticles in the diluted solution. The optimized solution was subjected to dialysis process to remove any unreacted solvent. UVS of the optimized solution after dialysis showed the plasmon resonance peak shifting to {approx}440 nm indicating the reduction of Ag ions into zero-valent Ag. This solution was dried at 80 {sup o}C and the resultant HPC capped Ag (HPC/Ag) nanoparticles were studied using transmission electron microscopy (TEM) for their particle size and morphology. The particle size distribution (PSD) analysis of these nanoparticles showed skewed distribution plot with particle size ranging from 3 to 18 nm. The nanoparticles were characterized for phase composition using X-ray diffractrometry (XRD) and Fourier transform infrared spectroscopy (FT-IR).

Francis, L. [University of Genova, Department of Chemistry and Industrial Chemistry, via Dodecaneso 31, 16146 Genova (Italy)] [University of Genova, Department of Chemistry and Industrial Chemistry, via Dodecaneso 31, 16146 Genova (Italy); Balakrishnan, A. [Laboratoire SIMaP - GPM2, Grenoble-INP/UJF/CNRS BP46, 38042 Saint Martin d'Heres cedex (France)] [Laboratoire SIMaP - GPM2, Grenoble-INP/UJF/CNRS BP46, 38042 Saint Martin d'Heres cedex (France); Sanosh, K.P. [Department of Innovation Engineering, University of Lecce, via per Monteroni, 73100 Lecce (Italy)] [Department of Innovation Engineering, University of Lecce, via per Monteroni, 73100 Lecce (Italy); Marsano, E., E-mail: marsano@chimica.unige.it [University of Genova, Department of Chemistry and Industrial Chemistry, via Dodecaneso 31, 16146 Genova (Italy)

2010-08-15

83

In vitro bioactivity and biocompatibility of calcium phosphate cements using Hydroxy-propyl-methyl-Cellulose (HPMC)  

NASA Astrophysics Data System (ADS)

In this study, the bioactivity and biocompatibility of new calcium phosphate bone cements (CPC) using Hydroxy-propyl-methyl-Cellulose (HPMC) was evaluated to understand the effect of HPMC on bone-bonding apatite formation and biocompatibility. In vitro bioactivity was investigated by incubating the CPC samples containing different ratios of HPMC (0%, 2% and 4% HPMC) in simulated body fluid (SBF) for 2, 7, 14 and 28 days. The formation of bone like apatite was confirmed on CPC surfaces by SEM and XRD analysis. Higher HPMC content of CPC showed faster apatite deposition in SBF. A high Ca ion dissolution profile was also reported with an increase of pH in all samples in SBF. The apatite formation ability of these CPC samples was found to be dependent on both surface chemistry and immersion time in SBF. The In vitro cytotoxicity test showed that the CPC samples with 4% HPMC were fairly cytocompatible for fibroblast L-929 cells. SEM images showed that MG-63 cells were successfully attached to the CPC samples and well proliferated.

Jyoti, M. Anirban; Thai, Van Viet; Min, Young Ki; Lee, Byong-Taek; Song, Ho-Yeon

2010-12-01

84

Vibrational spectra and normal coordinate analysis of 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate  

NASA Astrophysics Data System (ADS)

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FTIR spectroscopy in the range 50-4000 cm-1 and 450-4000 cm-1 respectively, for 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate (2H3MPPLC) molecule. The molecular structure, fundamental vibrational frequencies and intensities of the vibrational bands were interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) and ab initio HF methods with 6-31G(d,p) basis set. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The scaled B3LYP/6-31G(d,p) results show the best agreement with the experimental values over the other method. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results confirm the occurrence of intramolecular charge-transfer (ICT) within the molecule. The dipole moment (?), polarizability (?) and hyperpolarizability (?) of the investigated molecule has been computed using B3LYP/6-31G(d,p) method. Mulliken population analysis on atomic charges was also calculated. Besides, frontier molecular orbitals, molecular electrostatic potential (MEP) and thermodynamic properties were performed.

Muthu, S.; Renuga, S.

2014-11-01

85

Vibrational spectra and normal coordinate analysis of 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate.  

PubMed

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FTIR spectroscopy in the range 50-4000 cm(-1) and 450-4000 cm(-1) respectively, for 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate (2H3MPPLC) molecule. The molecular structure, fundamental vibrational frequencies and intensities of the vibrational bands were interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) and ab initio HF methods with 6-31G(d,p) basis set. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The scaled B3LYP/6-31G(d,p) results show the best agreement with the experimental values over the other method. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results confirm the occurrence of intramolecular charge-transfer (ICT) within the molecule. The dipole moment (?), polarizability (?) and hyperpolarizability (?) of the investigated molecule has been computed using B3LYP/6-31G(d,p) method. Mulliken population analysis on atomic charges was also calculated. Besides, frontier molecular orbitals, molecular electrostatic potential (MEP) and thermodynamic properties were performed. PMID:24878438

Muthu, S; Renuga, S

2014-11-11

86

Adaptation of an L-Proline Adenylation Domain to Use 4-Propyl-L-Proline in the Evolution of Lincosamide Biosynthesis  

PubMed Central

Clinically used lincosamide antibiotic lincomycin incorporates in its structure 4-propyl-L-proline (PPL), an unusual amino acid, while celesticetin, a less efficient related compound, makes use of proteinogenic L-proline. Biochemical characterization, as well as phylogenetic analysis and homology modelling combined with the molecular dynamics simulation were employed for complex comparative analysis of the orthologous protein pair LmbC and CcbC from the biosynthesis of lincomycin and celesticetin, respectively. The analysis proved the compared proteins to be the stand-alone adenylation domains strictly preferring their own natural substrate, PPL or L-proline. The LmbC substrate binding pocket is adapted to accomodate a rare PPL precursor. When compared with L-proline specific ones, several large amino acid residues were replaced by smaller ones opening a channel which allowed the alkyl side chain of PPL to be accommodated. One of the most important differences, that of the residue corresponding to V306 in CcbC changing to G308 in LmbC, was investigated in vitro and in silico. Moreover, the substrate binding pocket rearrangement also allowed LmbC to effectively adenylate 4-butyl-L-proline and 4-pentyl-L-proline, substrates with even longer alkyl side chains, producing more potent lincosamides. A shift of LmbC substrate specificity appears to be an integral part of biosynthetic pathway adaptation to the PPL acquisition. A set of genes presumably coding for the PPL biosynthesis is present in the lincomycin - but not in the celesticetin cluster; their homologs are found in biosynthetic clusters of some pyrrolobenzodiazepines (PBD) and hormaomycin. Whereas in the PBD and hormaomycin pathways the arising precursors are condensed to another amino acid moiety, the LmbC protein is the first functionally proved part of a unique condensation enzyme connecting PPL to the specialized amino sugar building unit. PMID:24386435

Kadl?ík, Stanislav; Ku?era, Tomáš; Chalupská, Dominika; Gažák, Radek; Kob?rská, Markéta; Ulanová, Dana; Kopecký, Jan; Kutejová, Eva; Najmanová, Lucie; Janata, Ji?í

2013-01-01

87

Evaluation of a Simple in-House Test to Presumptively Differentiate Mycobacterium tuberculosis Complex from Nontuberculous Mycobacteria by Detection of p-Nitrobenzoic Acid Metabolites  

PubMed Central

The timely differentiation of Mycobacterium tuberculosis complex (MTC) and non-tubercular mycobacterium (NTM) species is urgently needed in patient care since the routine laboratory method is time consuming and cumbersome. An easy and cheap method which can successfully distinguish MTC from NTM was established and evaluated. 38 mycobacterial type and reference strains and 65 clinical isolates representing 10 species of mycobacterium were included in this study. Metabolites of p-nitrobenzoic acid (PNB) reduction were identified using liquid chromatography and tandem mass spectrometry (LC/MS/MS). A spectrophotometric method was developed to detect these metabolites, which was evaluated on a number of MTC and NTM species. All of the tested NTM species and strains reduced PNB to p-aminobenzoic acid (PABA), while none of the MTC strains showed a similar activity. Spectrophotometric detection of PABA had 100% sensitivity and specificity for MTC and NTM differentiation among the type strains and the clinical isolates tested. PABA was identified as one of the metabolites of PNB reduction. All the tested NTM species metabolized PNB to PABA whereas the MTC members lacked this activity. A simple, specific and cost-effective method based on PABA production was established in order to discriminate MTC from NTM from cultured organisms. PMID:24260497

Wang, Guirong; Yu, Xia; Liang, Qian; Chen, Suting; Wilson, Stuart; Huang, Hairong

2013-01-01

88

Utilization of Boron Compounds for the Modification of Suberoyl Anilide Hydroxamic Acid as Inhibitor of Histone Deacetylase Class II Homo sapiens  

PubMed Central

Histone deacetylase (HDAC) has a critical function in regulating gene expression. The inhibition of HDAC has developed as an interesting anticancer research area that targets biological processes such as cell cycle, apoptosis, and cell differentiation. In this study, an HDAC inhibitor that is available commercially, suberoyl anilide hydroxamic acid (SAHA), has been modified to improve its efficacy and reduce the side effects of the compound. Hydrophobic cap and zinc-binding group of these compounds were substituted with boron-based compounds, whereas the linker region was substituted with p-aminobenzoic acid. The molecular docking analysis resulted in 8 ligands with ?Gbinding value more negative than the standards, SAHA and trichostatin A (TSA). That ligands were analyzed based on the nature of QSAR, pharmacological properties, and ADME-Tox. It is conducted to obtain a potent inhibitor of HDAC class II Homo sapiens. The screening process result gave one best ligand, Nova2 (513246-99-6), which was then further studied by molecular dynamics simulations. PMID:25214833

Bakri, Ridla; Parikesit, Arli Aditya; Satriyanto, Cipta Prio; Kerami, Djati; Tambunan, Usman Sumo Friend

2014-01-01

89

Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite.  

PubMed

Homologous series of alkyl phosphonic acids and alkyl sulfonic acids, along with inorganic orthophosphate and sulfate, have been identified in water extracts of the Murchison meteorite after conversion to their t-butyl dimethylsilyl (tBDMS) derivatives. The methyl, ethyl, propyl, and butyl compounds have been observed in both series. Five of the eight possible alkyl phosphonic acids and seven of the eight possible alkyl sulfonic acids through C4 have been identified. Abundances decrease with increasing carbon number as observed of other homologous series indigenous to Murchison. Concentrations range downward from approximately 380 nmol/gram in alkyl sulfonic acid series, and from 9 nmol/gram in the alkyl phosphonic acid series. Inorganic phosphate is present at about 25 micromoles/gram. PMID:11537207

Cooper, G W; Onwo, W M; Cronin, J R

1992-01-01

90

Chemical Name Container size Cabinet Level # of containers (Ethylenedinitrilo) tetraacetic acid, disodium salt 500g 2 B 1  

E-print Network

acid 3kg 8 B 2 Nitric acid 1000ml 8 B 1 N-propyl alcohol 8pt 5 A 1 O-phosphoric acid 2.5L 8 A 3 #12Chemical Name Container size Cabinet Level # of containers (Ethylenedinitrilo) tetraacetic acid-5 dipheyloxazole (PPO) crystalline 100gm 1 D 2 4,4-dicarboxy-2,2-biquinoline, bicinchoninic acid 25g 3 E 1

Capecchi, Mario R.

91

Plant-mediated stereoselective biotransformation of phenylglyoxylic acid esters.  

PubMed

Enantioselective reduction of the carbonyl group of three phenylglyoxylic acid esters (methyl, ethyl, and n-propyl esters, 2-4) was conducted using blended plant materials (roots of carrot, beetroot, celeriac and parsley; apple). All used biocatalysts transformed these esters to the corresponding mandelic acid esters with high yield, preferably into the respective R-enantiomer. Butanedione addition improved the enantioselectivity of the reaction. PMID:25265851

Maczka, Wanda Krystyna; Grabarczyk, Ma?gorzata; Wi?ska, Katarzyna; Anio?, Miros?aw

2014-01-01

92

Per-O-(3-hydroxy)propyl-beta-cyclodextrin: a cyclodextrin derivative bearing only primary hydroxyl groups.  

PubMed

Natural beta-cyclodextrin (cyclomaltoheptaose) was treated with sodium hydride and allyl bromide to form the per-O-allyl-beta-cyclodextrin. 9-BBN, sodium hydroxide and hydrogen peroxide were then added to form, after adequate treatments, the desired per-O-(3-hydroxy)propyl-beta-cyclodextrin in yields close to 65%. This modified cyclodextrin, which bears only primary hydroxyl groups, can be used as a macro-initiator of the anionic polymerisation of ethylene oxide to form star-shaped polymers. The presence of only primary hydroxyl groups allows us to expect identical initiation kinetics for all the hydroxyl groups of the modified glucopyranosyl units. PMID:17612512

Badi, Nezha; Guégan, Philippe

2007-10-15

93

N-Acetyl-S-(n-Propyl)-L-Cysteine in Urine from Workers Exposed to 1-Bromopropane in Foam Cushion Spray Adhesives  

PubMed Central

1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives, metal, precision, and electronics cleaning solvents. Mechanisms of toxicity of 1-BP are not fully understood, but it may be a neurological and reproductive toxicant. Sparse exposure information prompted this study using 1-BP air sampling and urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving debromination. Research objectives were to evaluate the utility of urinary N-acetyl-S-(n-propyl)-L-cysteine (AcPrCys) for assessing exposure to 1-BP and compare it to urinary bromide [Br(?)] previously reported for these workers. Forty-eight-hour urine specimens were obtained from 30 workers at two factories where 1-BP spray adhesives were used to construct polyurethane foam seat cushions. Urine specimens were also obtained from 21 unexposed control subjects. All the workers' urine was collected into composite samples representing three time intervals: at work, after work but before bedtime, and upon awakening. Time-weighted average (TWA) geometric mean breathing zone concentrations were 92.4 and 10.5 p.p.m. for spraying and non-spraying jobs, respectively. Urinary AcPrCys showed the same trend as TWA exposures to 1-BP: higher levels were observed for sprayers. Associations of AcPrCys concentrations, adjusted for creatinine, with 1-BP TWA exposure were statistically significant for both sprayers (P < 0.05) and non-sprayers (P < 0.01). Spearman correlation coefficients for AcPrCys and Br(?) analyses determined from the same urine specimens were highly correlated (P < 0.0001). This study confirms that urinary AcPrCys is an important 1-BP metabolite and an effective biomarker for highly exposed foam cushion workers. PMID:19706636

Hanley, Kevin W.; Petersen, Martin R.; Cheever, Kenneth L.; Luo, Lian

2009-01-01

94

Bioconcentration, metabolism and neurotoxicity of the organophorous flame retardant 1,3-dichloro 2-propyl phosphate (TDCPP) to zebrafish.  

PubMed

Organophosphate flame retardants are ubiquitous environmental contaminants; however, knowledge is limited regarding their environmental health risks and toxicity. Here, we investigated the effects of acute and long-term exposure to tris(1,3-dichloro-2-propyl) phosphate (TDCPP) to the nervous system of zebrafish. Zebrafish embryos (2h post-fertilization) were exposed to TDCPP (0-100?g/L) for 6 months up until sexual maturation. Concentrations of TDCPP and its metabolic product (bis(1,3-dichloro-2-propyl) phosphate, BDCPP) were measured in the tissues of 5 day post-fertilization (dpf) larvae. There was no effect on locomotion, acetylcholinesterase activity, levels of the neurotransmitters dopamine and serotonin, and expression of mRNAs and proteins related to central nervous system development (e.g., myelin basic protein, ?1-tubulin) in any exposure group. However, in adult fish, reductions of dopamine and serotonin levels were detected in the brains of females but not males. Downregulation of nervous system development genes was observed in both the male and female brain tissues. TDCPP concentrations were measured in adult fish tissues including the brain, and greater levels were detected in females. Our results showed that females are more sensitive to TDCPP stress than males in terms of TDCPP-induced neurotoxicity. We demonstrate that long-term exposure to lower concentrations of TDCPP in fish can lead to neurotoxicity. PMID:25461749

Wang, Qiangwei; Lam, James Chung-Wah; Man, Yin-Chung; Lai, Nelson Lok-Shun; Kwok, Karen Ying; Guo, Yong Yong; Lam, Paul Kwan-Sing; Zhou, Bingsheng

2015-01-01

95

RATE CONSTANTS FOR THE REACTIONS OF OH RADICALS AND CL ATOMS WITH DI-N-PROPYL ETHER AND DI-N-BUTYL ETHER AND THEIR DEUTERATED ANALOGS. (R825252)  

EPA Science Inventory

Using relative rate methods, rate constants for the gas-phase reactions of OH radicals and Cl atoms with di- n -propyl ether, di- n -propyl ether-d14, di- n -butyl ether and di- n -butyl ether-d18 have been measured at 296 ? 2 K and atmos...

96

Transcriptome analysis provides new insights into liver changes induced in the rat upon dietary administration of the food additives butylated hydroxytoluene, curcumin, propyl gallate and thiabendazole  

Microsoft Academic Search

Transcriptomics was performed to gain insight into mechanisms of food additives butylated hydroxytoluene (BHT), curcumin (CC), propyl gallate (PG), and thiabendazole (TB), additives for which interactions in the liver can not be excluded. Additives were administered in diets for 28 days to Sprague–Dawley rats and cDNA microarray experiments were performed on hepatic RNA. BHT induced changes in the expression of

Rob Stierum; Ana Conesa; Wilbert Heijne; Ben van Ommen; Karin Junker; Mary P. Scott; Roger J. Price; Clive Meredith; Brian G. Lake; John Groten

2008-01-01

97

Further studies into the photodissociation pathways of 2-bromo-2-nitropropane and the dissociation channels of the 2-nitro-2-propyl radical intermediate.  

PubMed

These experiments investigate the decomposition mechanisms of geminal dinitro energetic materials by photolytically generating two key intermediates: 2-nitropropene and 2-nitro-2-propyl radicals. To characterize the unimolecular dissociation of each intermediate, we form them under collision-free conditions using the photodissociation of 2-bromo-2-nitropropane; the intermediates are formed at high internal energies and undergo a multitude of subsequent unimolecular dissociation events investigated herein. Complementing our prior work on this system, the new data obtained with a crossed-laser molecular beam scattering apparatus with VUV photoionization detection at Taiwan's National Synchrotron Radiation Research Center (NSRRC) and new velocity map imaging data better characterize two of the four primary 193 nm photodissociation channels. The C-Br photofission channel forming the 2-nitro-2-propyl radicals has a trimodal recoil kinetic energy distribution, P(ET), suggesting that the 2-nitro-2-propyl radicals are formed both in the ground electronic state and in two low-lying excited electronic states. The new data also revise the HBr photoelimination P(ET) forming the 2-nitropropene intermediate. We then resolved the multiple competing unimolecular dissociation channels of each photoproduct, confirming many of the channels detected in the prior study, but not all. The new data detected HONO product at m/e = 47 using 11.3 eV photoionization from both intermediates; analysis of the momentum-matched products allows us to establish that both 2-nitro-2-propyl ? HONO + CH3CCH2 and 2-nitropropene ? HONO + C3H4 occur. Photoionization at 9.5 eV allowed us to detect the mass 71 coproduct formed in OH loss from 2-nitro-2-propyl; a channel missed in our prior study. The dynamics of the highly exothermic 2-nitro-2-propyl ? NO + acetone dissociation is also better characterized; it evidences a sideways scattered angular distribution. The detection of some stable 2-nitropropene photoproducts allows us to fit signal previously assigned to H loss from 2-nitro-2-propyl radicals. Overall, the data provide a comprehensive study of the unimolecular dissociation channels of these important nitro-containing intermediates. PMID:24947044

Booth, Ryan S; Brynteson, Matthew D; Lee, Shih-Huang; Lin, J J; Butler, Laurie J

2014-07-01

98

{4-Bromo-2-[3-(diethyl­ammonio)propyl­imino­meth­yl]phenolato}diiodidozinc(II) methanol solvate  

PubMed Central

In the title complex, [ZnI2(C14H21BrN2O)]·CH3OH, the asymmetric unit consists of a mononuclear zinc(II) complex mol­ecule and a methanol solvent mol­ecule. The compound was derived from the zwitterionic form of the Schiff base 4-bromo-2-[3-(diethyl­amino)propyl­imino­meth­yl]phenol. The ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand and by two iodide ions in a distorted tetra­hedral coordination. In the crystal structure, the methanol mol­ecules are linked to the Schiff base mol­ecules through N—H?O and O—H?O hydrogen bonds. One I atom is disordered over two positions in a 0.702?(19):0.298?(19) ratio. PMID:21578061

Zhu, Xue-Wen; Yin, Zhi-Gang; Yang, Xu-Zhao; Li, Gang-Sen; Zhang, Chun-Xia

2009-01-01

99

The Laboratory Rotational Spectrum of Iso-Propyl Cyanide and AN Astronomical Search in Sagittarius B2(N)  

NASA Astrophysics Data System (ADS)

We have carried out a molecular line survey of Sagittarius B2(N) in the 3 mm region with selected recordings at 2 and 1.3 mm to probe the chemical complexity in massive star-forming regions. Noteworthy results include the detection of aminoacetonitrile, a possible precursor of the aminoacid glycine, the detection of ^{13}C isotopologs of vinyl cyanide, and the detection of ethyl formate as well as normal-propyl cyanide. The heavy atoms in the latter molecule form a chain. An isomer with a branched structure, iso-propyl cyanide, also exists, but its rotational spectrum has only been recorded in few transitions up to 40 GHz. Therefore, laboratory measurements were extended. The molecule is rather asymmetric (? = -0.5766) with a strong a-dipole moment component of 4.05 (2) D and a still sizable c-component of 1.4 (2) D.^e Measurements in Köln were carried out in selected regions between 40 and 600 GHz. Since the c-type transitions appeared to be weaker than predicted additional Stark (and also zero-field) measurements have been carried out in Hannover between 6 and 20 GHz. We will present results of these laboratory spectroscopic investigations as well as the outcome of a search for the molecule in our Sgr B2(N) line survey. A. Belloche, K. M. Menten, C. Comito, H. S. P. Müller, P. Schilke, J. Ott, S. Thorwirth, C. Hieret, Astron. Astrophys. 482 (2008) 179; Erratum 492 (2008) 796. H. S. P. Müller, A. Belloche, K. M. Menten, C. Comito, P. Schilke, J. Mol. Spectrosc. 251 (2008) 319. A. Belloche, R. T. Garrod, H. S. P. Müller, K. M. Menten, C. Comito, P. Schilke, Astron. Astrophys. (2009), accepted. G. E. Herberich, Z. Naturforsch. 22a (1967) 543. J. R. Durig, Y. S. Li, J. Mol. Struct. 21 (1974) 289.

Müller, Holger S. P.; Coutens, A.; Walters, A.; Grabow, J.-U.; Belloche, A.; Menten, K. M.; Schlemmer, S.

2009-06-01

100

Predictors of Tris(1,3-dichloro-2-propyl) phosphate Metabolite in the Urine of Office Workers  

PubMed Central

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is a flame retardant widely used in furniture containing polyurethane foam. It is a carcinogen, endocrine disruptor, and potentially neurotoxic. Our objectives were to characterize exposure of adult office workers (n=29) to TDCPP by measuring its primary metabolite, bis(1,3-dichloro-2-propyl) phosphate (BDCPP), in their urine; measuring TDCPP in dust from their homes; offices and vehicles; and assessing possible predictors of exposure. We identified TDCPP in 99% of dust (GM=4.43 µg/g) and BDCPP in 100% of urine samples (GM=408 pg/mL). Concentrations of TDCPP in dust were significantly higher in vehicles (GM=12.5 µg/g) and offices (GM=6.06 µg/g) than in dust from the main living area (GM=4.21 µg/g) or bedrooms (GM=1.40 µg/g) of worker homes. Urinary BDCPP concentrations among participants who worked in a new office building were 26% of those who worked in older buildings (p=0.01). We found some evidence of a positive trend between urinary BDCPP and TDCPP in office dust that was not observed in the other microenvironments and may be related to the timing of urine sample collection during the afternoon of a workday. Overall our findings suggest that exposure to TDCPP in the work environment is one of the contributors to the personal exposure for office workers. Further research is needed to confirm specific exposure sources (e.g., polyurethane foam), determine the importance of exposure in other microenvironments such as homes and vehicles, and address the inhalation and dermal exposure pathways. PMID:23523854

Carignan, Courtney C.; McClean, Michael D.; Cooper, Ellen M.; Watkins, Deborah J.; Fraser, Alicia J.; Heiger-Bernays, Wendy; Stapleton, Heather M.; Webster, Thomas F.

2013-01-01

101

Predictors of tris(1,3-dichloro-2-propyl) phosphate metabolite in the urine of office workers.  

PubMed

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is a flame retardant widely used in furniture containing polyurethane foam. It is a carcinogen, endocrine disruptor, and potentially neurotoxic. Our objectives were to characterize exposure of adult office workers (n=29) to TDCPP by measuring its primary metabolite, bis(1,3-dichloro-2-propyl) phosphate (BDCPP), in their urine; measuring TDCPP in dust from their homes; offices and vehicles; and assessing possible predictors of exposure. We identified TDCPP in 99% of dust (GM=4.43?g/g) and BDCPP in 100% of urine samples (GM=408pg/mL). Concentrations of TDCPP were significantly higher in dust from vehicles (GM=12.5?g/g) and offices (GM=6.06?g/g) than in dust from the main living area (GM=4.21?g/g) or bedrooms (GM=1.40?g/g) of worker homes. Urinary BDCPP concentrations among participants who worked in a new office building were 26% of those who worked in older buildings (p=0.01). We found some evidence of a positive trend between urinary BDCPP and TDCPP in office dust that was not observed in the other microenvironments and may be related to the timing of urine sample collection during the afternoon of a workday. Overall our findings suggest that exposure to TDCPP in the work environment is one of the contributors to the personal exposure for office workers. Further research is needed to confirm specific exposure sources (e.g., polyurethane foam), determine the importance of exposure in other microenvironments such as homes and vehicles, and address the inhalation and dermal exposure pathways. PMID:23523854

Carignan, Courtney C; McClean, Michael D; Cooper, Ellen M; Watkins, Deborah J; Fraser, Alicia J; Heiger-Bernays, Wendy; Stapleton, Heather M; Webster, Thomas F

2013-05-01

102

Synthesis of N-phenyl-N-(3-(piperidin-1-yl)propyl)benzofuran-2-carboxamides as new selective ligands for sigma receptors  

PubMed Central

Novel benzofuran-2-carboxamide ligands, which are selective for sigma receptors, have been synthesized via a microwave-assisted Perkin rearrangement reaction and a modified Finkelstein halogen-exchange used to facilitate N-alkylation. The ligands synthesized are the 3-methyl-N-phenyl-N-(3-(piperidin-1-yl)propyl)benzofuran-2-carboxamides (KSCM-1, KSCM-5 and KSCM-11). The benzofuran-2-carboxamide structure was N-arylated and N-alkylated to include both N-phenyl and N-(3-(piperidin-1-yl)propyl substituents respectively. These new carboxamides exhibit high affinity at the sigma-1 receptor with Ki values ranging from 7.8 – 34nM. Ligand KSCM-1 with two methoxy substituents at C-5 and C-6 of the benzofuran ring, and Ki = 27.5nM at sigma-1 was found to be more selective for sigma-1 over sigma-2. 3-methyl-N-phenyl-N-(3-(piperidin-1-yl)propyl)benzofuran-2-carboxamides PMID:23084435

Marriott, Karla-Sue C.; Morrison, Andrew Z.; Moore, Misty; Olubajo, Olarongbe; Stewart, Leonard E.

2012-01-01

103

Separation and solvent extraction of vanadium and uranium with n-propyl 2,3,4-trihydroxybenzoate.  

PubMed

A spectrophotometric method is described for the separation and determination of trace quantities of vanadium(IV) and (V) from uranium(VI). Vanadium is selectively separated from uranium by extraction at pH 6.5 into n-propyl 2,3,4-trihydroxybenzoate (PTB) dissolved in t-pentanol. Up to 120 microg of vanadium can be determined by measuring the absorbance of the blue complex in the organic phase at 585 nm. Uranium(VI) remains in the aqueous layer and can be determined spectrophotometrically by its reaction with PTB in aqueous acetone to produce a brown-red colour at pH 7.6-8.8. Solutions containing 25-275 microg of uranium absorb at 370-380 nm according to Beer's law. By modification, this procedure can be used for the determination of the two metals in native phosphate rocks. The effects of diverse ions on the determination of vanadium and uranium have also been examined. PMID:18960575

Jasim, F

1969-06-01

104

Imprinted propyl gallate electrochemical sensor based on graphene/single walled carbon nanotubes/sol-gel film.  

PubMed

A novel imprinted sol-gel electrochemical sensor for the determination of propyl gallate (PG) was developed based on a composite of graphene and single walled carbon nanotubes (GR-SWCNTs). It was fabricated by stepwise modifying GR-SWCNTs and molecularly imprinted polymers and stored in 0.10molL(-1) phosphate buffer solution pH 6.0, which endowed the sensor good sensitivity and selective recognition towards template molecules. The morphology and specific adsorption capacity of the sensor was characterized by scanning electron microscope and electrochemical methods, respectively. Under the optimized conditions, a linear range of the sensor to PG was 8.0×10(-8)-2.6×10(-3)molL(-1) with a limit of detection of 5.0×10(-8)molL(-1) (S/N=3). The sensor exhibited specificity and selectivity towards template molecules as well as excellent reproducibility, regeneration and stability. Furthermore, the sensor could be applied to determine PG in edible oils, instant noodles and cookies with satisfactory results. PMID:25660855

Xu, Guilin; Chi, Yu; Li, Lu; Liu, Shouhua; Kan, Xianwen

2015-06-15

105

Psychotomimetic opiate receptors labeled and visualized with (+)-(/sup 3/H)3-(3-hydroxyphenyl)-N-(1-propyl)piperidine  

SciTech Connect

3-(3-Hydroxyphenyl)-N-(1-propyl)piperidine (3-PPP) has been proposed as a selective dopamine autoreceptor agonist in the central nervous system. This report describes the pharmacology and localization of specific high-affinity binding sites for (+)-(/sup 3/H)3-PPP in brain. The drug specificity of (+)-(/sup 3/H)3-PPP binding is identical to that of sigma receptors, which may mediate psychotomimetic effects of some opiates. Haloperidol and the opioid derivatives, pentazocine, cyclazocine, and SKF 10,047 are potent inhibitors of (+)-(/sup 3/H)3-PPP binding. Stereoselectivity is exhibited for the (+) isomers of cyclazocine and SKF 10.047 at the sigma site, opposite to the stereoselectivity seen at ..mu.., sigma, and k opiate receptors. (+)-(/sup 3/H)3-PPP does not label dopamine receptors, as potent dopamine agonists and antagonists are weak inhibitors of binding and the localization of specific (+)-(/sup 3/H)3-PPP binding sites does not parallel that of dopamine neurons. Discrete localizations of (+)-(/sup 3/H)3-PPP binding sites in many brain areas including limbic, midbrain, brainstem, and cerebellar regions may explain psychotomimetic actions of opiates and behavior effects of 3-PPP. 41 references, 2 figures, 1 table.

Largent, B.L.; Gundlach, A.L.; Snyder, S.H.

1984-08-01

106

Over-expression of GAPDH in human colorectal carcinoma as a preferred target of 3-Bromopyruvate Propyl Ester  

PubMed Central

It has long been observed that many cancer cells exhibit increased aerobic glycolysis and rely more on this pathway to generate ATP and metabolic intermediates for cell proliferation. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key enzyme in glycolysis and has been known as a housekeeping molecule. In the present study, we found that GAPDH expression was significantly up-regulated in human colorectal carcinoma tissues compared to the adjacent normal tissues, and also increased in colon cancer cell lines compared to the non-tumor colon mucosa cells in culture. The expression of GAPDH was further elevated in the liver meta-static tissues compared to the original colon cancer tissue of the same patients, suggesting that high expression of GAPDH might play an important role in colon cancer development and metastasis. Importantly, we found that 3-bromopyruvate propyl ester (3-BrOP) preferentially inhibited GAPDH and exhibited potent activity in inducing colon cancer cell death by causing severe depletion of ATP. 3-BrOP at low concentrations (1–10 ?M) inhibited GAPDH and a much higher concentration (300 ?M) was required to inhibit hexokinase-2. The cytotoxic effect of 3-BrOP was associated with its inhibition of GAPDH, and colon cancer cells with loss of p53 were more sensitive to this compound. Our study suggests that GAPDH may be a potential target for colon cancer therapy. PMID:22350014

Tang, Zhenjie; Yuan, Shuqiang; Hu, Yumin; Zhang, Hui; Wu, Wenjing; Zeng, Zhaolei; Yang, Jing; Yun, Jingping

2012-01-01

107

Morphometric analysis of mice uteri treated with the preservatives methyl, ethyl, propyl, and butylparaben.  

PubMed

The alkyl esters of p-hydroxybenzoic acid (PHBA) known as parabens (Pbens) are widely used as preservatives in food, pharmaceuticals, and cosmetics. Several in vivo and in vitro studies have shown these compounds to be estrogenic. Here, for the first time, we present evidence of their estrogenicity using a morphometric analysis of uteri from mice treated with the preservatives methylparaben (MePben), ethylparaben (EtPben), propylparaben (PrPben), and butylparaben (BuPben) compared with estradiol (E2). Different groups of adult ovariectomized (Ovx) CD1 mice were subcutaneously (sc) treated daily for three days with two different equimolar doses (362 and 1086 micromol/kg) of the Pbens: MePben (55 and 165 mg/kg), EtPben (60 and 180 mg/kg), PrPben (65 and 195 mg/kg), BuPben (70 and 210 mg/kg), E2 (10 microg/kg; 0.036 micromol/kg), and vehicle (propyleneglycol; V, 10 mL/kg). On the fourth day, uteri were dissected, blotted, weighed, and placed in a fixative solution for 24 h. The paraffin embeded uteri were cut to obtain 7 microm thick transversal sections. Luminal epithelium heights (LEH), glandular epithelium heights (GEH), and myometrium widths (MW) were measured. The highest Pbens dose was able to produce uterotrophic effects (38 to 76%) compared to E2 efects (100%). The relative uterotrophic potency to E2 (100) was from 0.02 to 0.009. Significant increases (P < 0.05) in LEH, GEH, and MW as compared with V were obtained: LEH from 87 to 113% (E2 153%), GEH from 10 to 40% (E2 60%), and MW from 35 to 43% (E2 88%). These results confirm that Pbens at the doses assayed here induce estrogenic histological changes in the uteri of Ovx mice. PMID:15941009

Lemini, C; Hernández, A; Jaimez, R; Franco, Y; Avila, M E; Castell, A

2004-09-01

108

Antidepressant Potential of 5-HT3 Receptor Antagonist, N-n- propyl-3-ethoxyquinoxaline-2-carboxamide (6n)  

PubMed Central

The present study was designed to evaluate the antidepressant potential of 5-HT3 receptor antagonist N-n-propyl-3-ethoxyquinoxaline-2-carboxamide (6n). The compound ‘6n’ with optimum log P and pA2 value identified from a series of compounds synthesized in our laboratory was subjected to forced Swim Test (FST) (1, 2, and 4 mg/kg, i.p) and Tail Suspension Test (TST) (1, 2, and 4 mg/kg, i.p.). The compound ‘6n’ significantly reduced the duration of immobility in mice without affecting the baseline locomotion. Moreover, ‘6n’ (2 mg/kg, i.p.) potentiated the 5-hydroxytryptophan (5-HTP)-induced head twitch responses in mice and ‘6n’ at tested dose (1 and 2 mg/kg, i.p.) reversed the reserpine-induced hypothermia in rats. In interaction studies of ‘6n’ with various standard drugs/ligands using FST, ‘6n’ (1 mg/kg, i.p.) potentiated the antidepressant effect of venlafaxine (4 and 8 mg/kg, i.p.) and fluoxetine (10 and 20 mg/kg, i.p.). Additionally, ‘6n’ (1 and 2 mg/kg, i.p.) influenced the effect of harmane (5 mg/ kg, i.p.) as well as reversed the effect of parthenolide (1 mg/kg, i.p.) by reducing the duration of immobility in FST. Furthermore, ‘6n’ (1 mg/kg, i.p.) potentiated the effect of bupropion (10 and 20 mg/kg, i.p.) in TST. Chronic ‘6n’ (1 and 2 mg/kg, i.p.) treatment attenuated the behavioral abnormalities in olfactory bulbectomized rats. In conclusion, these various findings reiterated the antidepressant-like effects of ‘6n’ in behavioral models of depression. PMID:23493308

Mahesh, R; Bhatt, S; Devadoss, T; Jindal, AK; Gautam, BK; Pandey, DK

2012-01-01

109

Preparation and evaluation of gastroretentive floating pellets of metronidazole using Na-alginate and hydroxyl propyl methyl cellulose polymers.  

PubMed

Gastroretentive floating pellets of metronidazole were formulated to prolong the gastric residence time in order to obtain controlled release characteristics of the drug. Nine formulations of metronidazole floating pellets such as AX, BX, CX, AY, BY, CY, AZ, BZ and CZ were prepared by extrusion method using different quantities of hydroxyl propyl methyl cellulose (HPMC) polymers such as methocel K4M premium and methocel K100LV premium in the ratio of 2:1, 1:2 and 1.5:1.5 while the amount of Na-alginate used in the formulations was 3.50, 5.25 and 7.0 g, respectively. The in vitro dissolution studies were carried out in 900 mL of phosphate buffer (pH 1.2) at 37 +/- 0.5 degrees C and 50 rpm for 6 h using USP XXIV paddle method and the content of drug release was done by UV spectrophotometer at 277 nm. It was found that the percent release of metronidazole from different formulations was different with passing of time. The drug release profile of the formulation (AX) having Na-alginate 3.50 g methocel K4M premium and methocel K100LV premium in the ratio of 2:1 showed best fit to Higuchi release kinetics with R2 value of 0.994. Finally, it might be concluded that the polymers had significant effect on drug release kinetics of metronidazole from floating pellets. The selection and use of suitable polymers in appropriate ratio might be very important in designing floating pellets and using the capabilities of these polymers, suitable floating pellets of metronidazole with desirable release rate could be formulated. Thus, in vivo research studies by the future researchers will confirm the appropriateness of these formulated metronidazole floating pellets. PMID:24175426

Biswas, S K; Paul, S; Chowdhury, A; Das, J

2012-03-15

110

Instrumental dependent dissociations of n-propyl/isopropyl phosphonate isomers: evaluation of resonant and non-resonant vibrational activations.  

PubMed

Structural elucidation and distinction of isomeric neurotoxic agents remain a challenge. Tandem mass spectrometry can be used for this purpose in particular if a "diagnostic" product ion is observed. Different vibrational activation methods were investigated to enhance formation of diagnostic ions through consecutive processes from O,O-dialkyl alkylphosphonates. Resonant and non-resonant collisional activation and infrared multiphoton dissociation (IRMPD) were used with different mass spectrometers: a hybrid quadrupole Fourier transform ion cyclotron resonance (Qh-FTICR) and a hybrid linear ion trap-Orbitrap (LTQ/Orbitrap). Double resonance (DR) experiments, in ion cyclotron resonance (ICR) cell, were used for unambiguous determination of direct intermediate yielding diagnostic ions. From protonated n-propyl and isopropyl O-O-dialkyl-phosphonates, a diagnostic m/z 83 ion characterizes the isopropyl isomer. This ion is produced through consecutive dissociation processes. Conditions to favor its formation and observation using different activation methods were investigated. It was shown that with the LTQ, consecutive experimental steps of isolation/activation with modified trapping conditions limiting the low mass cut off (LMCO) effect were required, whereas with FT-ICR by CID and IRMPD the diagnostic ion detection was provided only by one activation step. Among the different investigated activation methods it was shown that by using low-pressure conditions or using non-resonant methods, efficient and fast differentiation of isomeric neurotoxic agents was obtained. This work constitutes a unique comparison of different activation modes for distinction of isomers showing the instrumental dependence characteristic of the consecutive processes. New insights in the dissociation pathways were obtained based on double-resonance IRMPD experiments using a FT-ICR instrument with limitation at low mass values. PMID:23722724

Bennaceur, Chafia; Afonso, Carlos; Alves, Sandra; Bossée, Anne; Tabet, Jean-Claude

2013-08-01

111

Instrumental Dependent Dissociations of n-Propyl/Isopropyl Phosphonate Isomers: Evaluation of Resonant and Non-Resonant Vibrational Activations  

NASA Astrophysics Data System (ADS)

Structural elucidation and distinction of isomeric neurotoxic agents remain a challenge. Tandem mass spectrometry can be used for this purpose in particular if a "diagnostic" product ion is observed. Different vibrational activation methods were investigated to enhance formation of diagnostic ions through consecutive processes from O,O-dialkyl alkylphosphonates. Resonant and non-resonant collisional activation and infrared multiphoton dissociation (IRMPD) were used with different mass spectrometers: a hybrid quadrupole Fourier transform ion cyclotron resonance (Qh-FTICR) and a hybrid linear ion trap-Orbitrap (LTQ/Orbitrap). Double resonance (DR) experiments, in ion cyclotron resonance (ICR) cell, were used for unambiguous determination of direct intermediate yielding diagnostic ions. From protonated n-propyl and isopropyl O-O-dialkyl-phosphonates, a diagnostic m/ z 83 ion characterizes the isopropyl isomer. This ion is produced through consecutive dissociation processes. Conditions to favor its formation and observation using different activation methods were investigated. It was shown that with the LTQ, consecutive experimental steps of isolation/activation with modified trapping conditions limiting the low mass cut off (LMCO) effect were required, whereas with FT-ICR by CID and IRMPD the diagnostic ion detection was provided only by one activation step. Among the different investigated activation methods it was shown that by using low-pressure conditions or using non-resonant methods, efficient and fast differentiation of isomeric neurotoxic agents was obtained. This work constitutes a unique comparison of different activation modes for distinction of isomers showing the instrumental dependence characteristic of the consecutive processes. New insights in the dissociation pathways were obtained based on double-resonance IRMPD experiments using a FT-ICR instrument with limitation at low mass values.

Bennaceur, Chafia; Afonso, Carlos; Alves, Sandra; Bossée, Anne; Tabet, Jean-Claude

2013-08-01

112

Organosilane grafted acid-activated beidellite clay for the removal of non-ionic alachlor and anionic imazaquin  

NASA Astrophysics Data System (ADS)

Clay adsorbents were prepared via two-step method to remove nonionic alachlor and anionic imazaquin herbicides from water. Firstly, layered beidellite clay, a member of smectite family, was treated with acid in hydrothermal process; secondly, common silane coupling agents, 3-chloro-propyl trimethoxysilane or triethoxy silane, were grafted on the acid treated samples to prepare adsorbent materials. The organically modified clay samples were characterized by powder X-ray diffraction, N2 gas adsorption, and FTIR spectroscopy. It was found that the selective modification of clay samples displayed higher adsorption capacity for herbicides compared with acid activated clay. And the amount of adsorption is increased with increasing the grafting amount of silane groups. Clay grafted with 3-chloro-propyl trimethoxysilane is an excellent adsorbent for both alachlor and imazaquin but triethoxy (octyl) silane grafted clay is more efficient only for alachlor removal.

Paul, Blain; Martens, Wayde N.; Frost, Ray L.

2011-04-01

113

The Quest for Complex Molecules in Space. Searches for Cyanides Related to n-PROPYL Cyanide in SGR B2(N)  

NASA Astrophysics Data System (ADS)

A molecular line survey was carried out with the IRAM 30 m telescope toward the prolific hot core Sgr B2(N) in order to explore its molecular complexity. The entire 3 mm range as well as selected regions at 2 and 1.3 mm were covered. Notable results include the detections of aminoacetonitrile, ethyl formate, n-propyl cyanide,^b and the singly substituted 13C isotopologs of vinyl cyanide. There exists a branched isomer of n-propyl cyanide: iso-propyl cyanide. A search for this isomer in our line survey required a laboratory spectroscopic investigation beforehand. Even though promising emission features have been found for this as well as other, related molecules, there are rather few uncontaminated lines. Overlap by other emission or some absorption features occurs frequently, and uncertainties about the position of the baseline also contribute to considering detections to be inconclusive. Nevertheless, the determination of upper limits or abundances among isomers and related molecules will help to constrain astrochemical pathways. We will present our results and discuss promising strategies to search for complex molecules in space. A. Belloche, K. M. Menten, C. Comito, H. S. P. Müller, P. Schilke, J. Ott, S. Thorwirth, C. Hieret, Astron. Astrophys. 482 (2008) 179. A. Belloche, R. T. Garrod, H. S. P. Müller, K. M. Menten, C. Comito, P. Schilke, Astron. Astrophys. 499 (2009), 215. H. S. P. Müller, A. Belloche, K. M. Menten, C. Comito, P. Schilke, J. Mol. Spectrosc. 251 (2008) 319. H. S. P. Müller, A. Coutens, A. Walters, J.-U. Grabow, S. Schlemmer, submitted to J. Mol. Spectrosc.

Müller, Holger S. P.; Schlemmer, S.; Belloche, A.; Menten, K. M.; Coutens, A.; Walters, A.; Grabow, J.-U.

2011-06-01

114

Low chain esters of stearic acid as phase change materials for thermal energy storage in buildings  

Microsoft Academic Search

Esterification of different commercial mixtures of stearic and palmitic acid with methyl, butyl and propyl alcohols was undertaken at the laboratory scale and the thermal properties of the esters were determined by Differential Scanning Calorimetry (DSC).Twelve products were obtained with melting points in the interval of 17–34°C and freezing points in the range of 20–32°C. About half of them are

D. Feldman; D. Banu; D. Hawes

1995-01-01

115

Adhesion improvement of SBR rubber by treatment with trichloroisocyanuric acid solutions in different esters  

Microsoft Academic Search

Ethyl, propyl and butyl acetates (EA, PA, BA, respectively) were used as solvents for trichloroisocyanuric acid (TCI) to chlorinate styrene–butadiene rubber (SBR). Characterization of the treated surfaces was carried out using ATR-IR spectroscopy, scanning electron microscopy (SEM), and contact angle measurements. Stress-strain measurements were also carried out to determine the mechanical properties of the treated rubber. Adhesion properties were studied

Mar??a D. Romero-Sánchez; M. Mercedes Pastor-Blas; José Miguel Mart??n-Mart??nez

2001-01-01

116

Crystal structure of 3,5-bis­(4-chloro­phen­yl)-1-propyl-1,3,5-tri­aza­cyclo­hexane  

PubMed Central

In the title mol­ecule, C18H21Cl2N3, the tri­aza­cyclo­hexane ring adopts a chair conformation with both 4-chloro­phenyl substituents in axial positions and the propyl group in an equatorial site. The dihedral angle between the planes of the benzene rings is 49.5?(1)°. In the crystal, mol­ecules are arranged in a head-to-tail fashion, forming columns along [010], and pairs of weak C—H?? inter­actions form inversion dimers between columns. PMID:25309226

Lefrada, Leila; Bouchemma, Ahcene; Bouacida, Sofiane; Claiser, Nicolas; Souhassou, Mohamed

2014-01-01

117

Volumetric Properties of the Mixture Propyl propanoate C6H12O2 + C6H13Cl 1-Chlorohexane (VMSD1212, LB4445_V)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propyl propanoate C6H12O2 + C6H13Cl 1-Chlorohexane (VMSD1212, LB4445_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

118

Heat of Mixing and Solution of Propyl benzoate C10H12O2 + C15H32 Pentadecane (HMSD1111, LB4172_H)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Heat of Mixing and Solution of Propyl benzoate C10H12O2 + C15H32 Pentadecane (HMSD1111, LB4172_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

119

Preliminary study of propyl bromide exposure among New Jersey dry cleaners as a result of a pending ban on perchloroethylene.  

PubMed

Many states are considering, and some states have actively pursued, banning the use of perchloroethylene (PERC) in dry cleaning establishments. Proposed legislation has led many dry cleaners to consider the use of products that contain greater than 90% n-propyl bromide (n-PB; also called 1-bromopropane or 1-BP). Very little information is known about toxicity and exposure to n-PB. Some n-PB-containing products are marketed as nonhazardous and "green" or "organic." This has resulted in some users perceiving the solvent as nontoxic and has resulted in at least one significant poisoning incident in New Jersey. In addition, many dry cleaning operators may not realize that the machine components and settings must be changed when converting from PERC to n-PB containing products. Not performing these modifications may result in overheating and significant leaks in the dry cleaning equipment. A preliminary investigation was conducted of the potential exposures to n-PB and isopropyl bromide (iso-PB; also called 2-bromopropane or 2-BP) among dry cleaners in New Jersey who have converted their machines from PERC to these new solvent products. Personal breathing zone and area samples were collected using the National Institute for Occupational Safety and Health Sampling and Analytical Method 1025, with a slight modification to gas chromatography conditions to facilitate better separation of n-PB from iso-PB. During the preliminary investigation, exposures to n-PB among some workers in two of three shops were measured that were greater than the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) for n-PB. The highest exposure measured among a dry cleaning machine operator was 54 parts per million (ppm) as an 8-hr time-weighted average, which is more than 5 times the ACGIH TLV of 10 ppm. The preliminary investigation also found that the work tasks most likely to result in the highest short-term exposures included the introduction of solvent to the machine, maintenance of the machine, unloading and handling of recently cleaned clothes, and interrupting the wash cycle of the machine. In addition, this assessment suggested that leaks may have contributed to exposure and may have resulted from normal machine wear over time, ineffective maintenance, and from the incompatibility of n-PB with gasket materials. PMID:20863050

Blando, James D; Schill, Donald P; De La Cruz, Mary Pauline; Zhang, Lin; Zhang, Junfeng

2010-09-01

120

Development of an HPLC-MS procedure for the quantification of N-acetyl-S-(n-propyl)-l-cysteine, the major urinary metabolite of 1-bromopropane in human urine.  

PubMed

An analytical procedure was developed for the detection and quantification of N-acetyl-S-(n-propyl)-l-cysteine (n-propylmercapturic acid, AcPrCys), a metabolite and biomarker for exposure to 1-bromopropane (1-BP). 1-BP is used as an industrial solvent and exposure is a health concern for industrial workers due to its toxicity. It has been associated with neurological disorders in both animals and humans. Urine sample preparation for the determination of AcPrCys consisted of solid phase extraction (SPE). Urine samples on preconditioned SPE (C18) columns were washed with 40% methanol/60% water solution prior to elution with acetone. Quantification was by means of a liquid chromatograph (LC) equipped with a mass spectrometer (MS) using an Aqua 3 microm C18 300A column and [d(7)]-AcPrCys was used as internal standard. Electrospray ionization (ESI) was used with the MS operated in the negative ion mode and selected ion monitoring (SIM) at m/z 204 for AcPrCys and m/z 211 for [d(7)]-AcPrCys. Demonstrated recovery of urine samples fortified at multiple levels (0.625-10 microg/ml) varied between 96 and 103% of theory with relative standard deviations (RSD) of 6.4% or less. The limit of detection (LOD) for the procedure was approximately 0.01 microg/ml AcPrCys in urine. These data will be discussed as well as other factors of the development of this test procedure. PMID:19237326

Cheever, K L; Marlow, K L; B'hymer, C; Hanley, K W; Lynch, D W

2009-03-15

121

Developmental exposure to the organophosphorus flame retardant tris(1,3-dichloro-2-propyl) phosphate: Estrogenic activity, endocrine disruption and reproductive effects on zebrafish.  

PubMed

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is an organophosphate flame retardant that is detectable in the environment and biota, prompting concern over its risk to wildlife and human health. Our objective was to investigate whether long-term exposure to low concentrations of TDCPP can affect fish reproduction. Zebrafish embryos were exposed to low concentrations (0, 4, 20 and 100?g/L) of TDCPP from 2h post-fertilization until sexual maturation. Exposure to TDCPP significantly increased plasma estradiol and testosterone levels in females, but had no effect in males. TDCPP exposure also caused a significant reduction in fecundity as indicated by decreased egg production. Real-time PCR was performed to examine selected genes in the hypothalamic-pituitary-gonadal (HPG) axis and liver. Principle component analysis (PCA) showed that sex hormone levels and fecundity were related to the mRNA level of several genes in the HPG axis. Furthermore, hepatic vitellogenin (vtg1 and vtg3) expression was upregulated in both females and males, suggesting TDCPP has estrogenic activity. Histological examination revealed promotion of oocyte maturation in the females, but retardation of spermiation in males. Reduced egg quality (e.g., egg diameter) and increased malformation rates were observed in the F1 generation. Chemical analysis showed significant levels of TDCPP and its metabolite bis(1,3-dichloro-2-propyl) phosphate in the gonads of males and females. In conclusion, long-term exposure to low concentrations of TDCPP impairs fish reproduction. PMID:25637911

Wang, Qiangwei; Lam, James C W; Han, Jian; Wang, Xianfeng; Guo, Yongyong; Lam, Paul K S; Zhou, Bingsheng

2015-03-01

122

NTP Carcinogenesis Bioassay of Propyl Gallate (CAS No. 121-79-9) in F344/N Rats and B6C3F1 Mice (Feed Study).  

PubMed

Propyl gallate is a white to nearly white odorless powder having a slightly bitter taste. Solutions of propyl gallate turn dark in the presence of iron or iron salts. Propyl gallate has been used since 1948 as an antioxidant to stabilize cosmetics, food packaging materials, and foods containing fats. As an additive, it may be found in edible fats, oils, mayonnaise, shortening, baked goods, candy, dried meat, fresh pork sausage, and dried milk, and it is used in hair grooming products, pressure-sensitive adhesives, lubricating oil additives, and transforming oils. A NTP Carcinogenesis bioassay of propyl gallate was conducted by feeding diets containing 6,000 or 12,000 ppm propyl gallate to groups of 50 F344/N rats and 50 B6C3F1 mice of each sex for 103 weeks. Groups of 50 untreated rats and 50 untreated mice of each sex served as controls. Survival of rats and mice was not adversely affected by propyl gallate, but mean body weights of dosed rats and mice of each sex were lower than those of the controls. At 104 weeks, mean body weights of low-and high-dose rats were 4% and 8% lower than those of the controls for males and 11% and 19% lower than those of the controls for females. Similarly, mean body weights of low-and high-dose mice were 5% and 8% lower than those of the controls for males and 11% (both dose groups) lower than those of the controls for females. Thyroid follicular-cell adenomas or carcinomas (combined) occurred in male rats with a statistically significant (P<0.05) positive trend, but the incidences in the dosed groups were not statistically significant in direct comparisons with the control groups. Moreover, the incidence of high-dose male rats with follicular-cell tumors (3/50, 6%) was not statistically different from the historical control rate (14/584, 2.4%) for the laboratory that conducted this bioassay. Rare tumors (an astrocytoma or a glioma) were found in the brains of two low-dose female rats. The incidence of all brain tumors in the Bioassay Program is only 0.86%. The absence of this tumor in the high-dose female rat group reduces the likelihood that this tumor is related to propyl gallate administration. Increased incidences of hepatic cytoplasmic vacuolization and suppurative inflammation of the prostate were observed in dosed male rats. These findings were considered to be related to administration of propyl gallate. Tumors (mostly benign) of the preputial gland, islet-cell tumors of the pancreas, and pheochromocytomas of the adrenal gland were observed with significantly (P<0.05) higher incidences in the low- dose male rats, but there was little evidence of an effect in the high-dose group. The incidences of male rats with tumors of the preputial gland were 1/50 (2%) for controls, 8/50 (16%) for the low-dose, and 0/50 (0%) for the high-dose group. Islet-cell tumors of the pancreas occurred in 2/50 (4%) control males, 9/50 (18%) low-dose males, and 4/50 (8%) for high-dose males. Pheochromocytomas of the adrenal gland were observed in 4/50 (8%) control males, 13/48 (25%) low-dose males, and 8/50 (16%) high-dose males. Negative trends (P<0.05) were observed for leukemia in male rats (16/50, 7/50, 6/50) and for fibroadenomas of the mammary gland in female rats (11/50, 2/50, 5/50). In male mice, malignant lymphoma was observed with a significantly (P

1982-12-01

123

Quantitation of total homocysteine in human plasma by derivatization to its N(O,S)-propoxycarbonyl propyl ester and gas chromatography-mass spectrometry analysis.  

PubMed

Much evidence supports the hypothesis that mild or moderate hyperhomocysteinaemia represents an important and independent risk factor for occlusive vascular diseases. Therefore, the accurate and reliable determination of total plasma homocysteine has gained major importance for risk assessment. Furthermore, it can help in the detection of folate and vitamin B12 deficiency. This has prompted us to develop a sensitive gas chromatography-mass spectrometry (GC-MS) method in order to quantify total homocysteine in human plasma. Prior to chromatography, reduced homocysteine was released from disulfide bonds by incubation with excess dithiothreitol and converted into its N(O,S)-propoxycarbonyl propyl ester by derivatization with n-propyl chloroformate. Aminoethylcysteine served as internal standard. The method proved to be highly linear over the entire concentration range examined (corresponding to 0-266 microM homocysteine) and showed intra-assay and inter-assay variation (relative standard deviations) of approximately 5 and 5-10%, respectively. External quality control by comparison with duplicate analysis performed on a HPLC-based system revealed satisfactory correlation. The newly developed GC-MS based method provides simple, reliable and fast quantification of total homocysteine and requires only inexpensive chemicals, which are easy to obtain. PMID:9291598

Sass, J O; Endres, W

1997-08-01

124

Actions of methyl-, propyl- and butylparaben on estrogen receptor-? and -? and the progesterone receptor in MCF-7 cancer cells and non-cancerous MCF-10A cells.  

PubMed

Numerous studies have shown that widely used parabens possess estrogenic properties. In the present study, we examined the effects of methyl-, propyl- and butylparaben on the mRNA and protein expression of estrogen receptor (ER)-? (ESR1) and -? (ESR2) and the progesterone receptor (PGR). Human MCF-7 breast cancer cells and MCF-10A non-transformed breast epithelial cells were exposed to parabens at a concentration of 20nM; 17?-estradiol at a concentration of 10nM, was used as a positive control. Both propyl- and butylparaben stimulated PGR mRNA expression in MCF-7 cells, whereas methyl- and propylparaben PGR protein expression. In MCF-10A cells, butyl- and propylparaben increased only PGR mRNA expression. All parabens increased ESR1 gene and protein expression in MCF-7 and with the exception of butylparaben in MCF-10A cells. All parabens significantly increased ESR2 mRNA and protein expression in MCF-7 cells, but in MCF-10A cells only ESR2 protein expression. In summary, by virtue of their stimulatory action on the expression of ESR1, ESR2 and PGR in cancer cells, parabens can be viewed as potential contributors to breast cancer progression. Extension, the actions of these parabens on the expression of ERs and PGR in non-cancerous cells point to possible actions on breast cancer initiation. PMID:25128701

Wróbel, Anna Maria; Gregoraszczuk, Ewa ?ucja

2014-11-01

125

Urinary Amino Acid Analysis: A Comparison of iTRAQ®-LC-MS/MS, GC-MS, and Amino Acid Analyzer  

PubMed Central

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ® derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ® tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ®-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27±5.22, 21.18±10.94, and 18.34±14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39±5.35, 6.23±3.84, and 35.37±29.42. Both GC-MS and iTRAQ®-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines. PMID:19481989

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L.; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J.

2009-01-01

126

Urinary amino acid analysis: a comparison of iTRAQ-LC-MS/MS, GC-MS, and amino acid analyzer.  

PubMed

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27+/-5.22, 21.18+/-10.94, and 18.34+/-14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39+/-5.35, 6.23+/-3.84, and 35.37+/-29.42. Both GC-MS and iTRAQ-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines. PMID:19481989

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J

2009-07-01

127

Conducting Polymer Based Nucleic Acid Sensor for Environment Monitoring  

NASA Astrophysics Data System (ADS)

Nucleic acid sensor based on polyaniline has been fabricated by covalently immobilizing double stranded calf thymus (dsCT) DNA onto perchlorate (ClO-4) doped polyaniline (PANI) film deposited onto indium-tin-oxide (ITO) glass plate using 1-(3-(dimethylamino) propyl)-3-ethylcarbodiimide hydrochloride (EDC)/N-hydroxyl succinimide (NHS) chemistry. These dsCT-DNA-PANI/ITO and PANI/ITO electrodes have been characterized using square wave voltammetry, electrochemical impedance, and Fourier-transform-infra-red (FTIR) measurements. This disposable dsCT-DNA-PANI/ITO bioelectrode is stable for about four months, can be used to detect arsenic trioxide (0.1ppm) in 30s.

Malhotra, Bansi Dhar; Prabhakar, Nirmal; Solanki, Pratima R.

128

Nonaqueous based microchip separation of toxic metal ions using 2-(5-bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol.  

PubMed

The colorimetric metal chelating agent, 2-(5-bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol (5-Br-PAPS), was demonstrated on a capillary electrophoresis microchip in the separation and detection of six metal ions of environmental concern, Cd2+, Pb2+, Cu2+, Co2+, Ni2+, and Hg2+. The inclusion of methanol in the buffer was found to improve both the separation efficiency and sensitivity, in addition to making the technique directly amenable to the application of solid-phase extraction. The combination of metal chelation with solid-phase extraction on a C18 silica gel microcolumn gave several hundred fold improvements in detection limits for the CE microchip measurements of toxic metal ions in water and extracted from a solid Plexiglas surface. PMID:12650264

Deng, Gang; Collins, Greg E

2003-03-14

129

(?-2-Pyridine-aldazine-?N,N':N'',N''')bis-[bis-(N,N-di-n-propyl-dithio-carbamato-?S,S')cadmium(II)].  

PubMed

The dinuclear centrosymmetric title compound, [Cd(2)(C(7)H(14)NS(2))(4)(C(12)H(10)N(4))], features a tetra-dentate 2-pyridine-aldazine ligand that chelates two Cd centres. The coordination geometry for Cd is distorted octa-hedral based on a cis-N(2)S(4) donor set. In the crystal structure, mol-ecules are connected into a supra-molecular chain aligned along the a direction via C-H?S and C-H?? contacts, and by ?-? contacts [centroid-to-centroid distance 3.5708?(15)?Å]. The n-propyl groups are each disordered, one equally over two sites and the other with a site-occupancy factor of 0.618?(8) for the major component. PMID:21201620

Poplaukhin, Pavel; Tiekink, Edward R T

2008-01-01

130

(?-2-Pyridine­aldazine-?4 N,N?:N??,N???)bis­[bis­(N,N-di-n-propyl­dithio­carbamato-?2 S,S?)cadmium(II)  

PubMed Central

The dinuclear centrosymmetric title compound, [Cd2(C7H14NS2)4(C12H10N4)], features a tetra­dentate 2-pyridine­aldazine ligand that chelates two Cd centres. The coordination geometry for Cd is distorted octa­hedral based on a cis-N2S4 donor set. In the crystal structure, mol­ecules are connected into a supra­molecular chain aligned along the a direction via C—H?S and C—H?? contacts, and by ?–? contacts [centroid-to-centroid distance 3.5708?(15)?Å]. The n-propyl groups are each disordered, one equally over two sites and the other with a site-occupancy factor of 0.618?(8) for the major component. PMID:21201620

Poplaukhin, Pavel; Tiekink, Edward R. T.

2008-01-01

131

Analysis of the flame retardant metabolites bis(1,3-dichloro-2-propyl) phosphate (BDCPP) and diphenyl phosphate (DPP) in urine using liquid chromatography-tandem mass spectrometry.  

PubMed

Organophosphate triesters tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate are widely used flame retardants (FRs) present in many products common to human environments, yet understanding of human exposure and health effects of these compounds is limited. Monitoring urinary metabolites as biomarkers of exposure can be a valuable aid for improving this understanding; however, no previously published method exists for the analysis of the primary TDCPP metabolite, bis(1,3-dichloro-2-propyl) phosphate (BDCPP), in human urine. Here, we present a method to extract the metabolites BDCPP and diphenyl phosphate (DPP) in human urine using mixed-mode anion exchange solid phase extraction and mass-labeled internal standards with analysis by atmospheric pressure chemical ionization liquid chromatography tandem mass spectrometry. The method detection limit was 8 pg mL(-1) urine for BDCPP and 204 pg mL(-1) for DPP. Recoveries of analytes spiked into urine ranged from 82 ± 10% to 91 ± 4% for BDCPP and from 72 ± 12% to 76 ± 8% for DPP. Analysis of a small number of urine samples (n=9) randomly collected from non-occupationally exposed adults revealed the presence of both BDCPP and DPP in all samples. Non-normalized urinary concentrations ranged from 46-1,662 pg BDCPP mL(-1) to 287-7,443 pg DPP mL(-1), with geometric means of 147 pg BDCPP mL(-1) and 1,074 pg DPP mL(-1). Levels of DPP were higher than those of BDCPP in 89% of samples. The presented method is simple and sufficiently sensitive to detect these FR metabolites in humans and may be applied to future studies to increase our understanding of exposure to and potential health effects from FRs. PMID:21830137

Cooper, E M; Covaci, A; van Nuijs, A L N; Webster, T F; Stapleton, H M

2011-10-01

132

In vitro and in vivo pharmacological characterization of ethyl-4-[trans-4-[((2S)-2-hydroxy-3-[4-hydroxy-3[(methylsulfonyl)amino]-phenoxy]propyl) amino]cyclohexyl]benzoate hydrochloride (SAR150640), a new potent and selective human beta3-adrenoceptor agonist for the treatment of preterm labor.  

PubMed

Ethyl-4-[trans-4-[((2S)-2-hydroxy-3-[4-hydroxy-3[(methylsulfonyl)amino] phenoxy]propyl) amino]cyclohexyl]benzoate hydrochloride (SAR150640) was characterized as a new potent and selective beta(3)-adrenoceptor agonist for the treatment of preterm labor. SAR150640 and its major metabolite, the corresponding acid 4-[trans-4-[((2S)-2-hydroxy-3-[4-hydroxy-3[(methylsulfonyl) amino] phenoxy]propyl)amino]cyclohexyl]benzoic acid (SSR500400), showed high affinity for beta(3)-adrenoceptors (K(i) = 73 and 358 nM) and greater potency than (-)-isoproterenol in increasing cAMP production in membrane preparations from human neuroblastoma cells (SKNMC), which express native beta(3)-adrenoceptors (pEC(50) = 6.5, 6.2, and 5.1, respectively). SAR150640 and SSR500400 also increased cAMP production in membrane preparations from human uterine smooth muscle cells (UtSMC), which also express native beta(3)-adrenoceptors (pEC(50) = 7.7 and 7.7, respectively). In these cells, SAR150640 dose-dependently inhibited oxytocin-induced intracellular Ca(2+) mobilization and extracellular signal-regulated kinase 1/2 phosphorylation. SAR150640 and SSR500400 had no beta(1)- or beta(2)-agonist or antagonist activity in guinea pig atrium and trachea, or in human isolated atrium and bronchus preparations. Both compounds concentration-dependently inhibited spontaneous contractions in human near-term myometrial strips, with greater potency than salbutamol and 4-[3-[(1,1-dimethylethyl)-amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazol-2-one hydrochloride (CGP12177) (pIC(50) = 6.4, 6.8, 5.9, and 5.8, respectively), but with similar potency to (-)-isoproterenol and atosiban (oxytocin/vasopressin V(1)a receptor antagonist). SAR150640 also inhibited the contractions induced by oxytocin and prostaglandin F(2alpha). In vivo, after intravenous administration, SAR150640 (1 and 6 mg/kg), but not atosiban (6 mg/kg), dose-dependently inhibited myometrial contractions in conscious unrestrained female cynomolgus monkeys, with no significant effects on heart rate or blood pressure. In contrast, salbutamol (50 and 250 microg/kg) had no inhibitory effect on uterine contractions, but it dose-dependently increased heart rate. These findings indicate a potential for the therapeutic use of SAR150640 in mammals during preterm labor. PMID:17351104

Croci, Tiziano; Cecchi, Roberto; Marini, Pietro; Rouget, Céline; Viviani, Nunzia; Germain, Guy; Guagnini, Fabio; Fradin, Yvon; Descamps, Laurence; Pascal, Marc; Advenier, Charles; Breuiller-Fouché, Michelle; Leroy, Marie-Josèphe; Bardou, Marc

2007-06-01

133

Application of Molecular Connectivity Indices to the Design of Supercritical Carbon Dioxide?Soluble Metal Ion Extractants: SC?CO2 Solubilities of Symmetrically Substituted Alkylenediphosphonic Acids  

Microsoft Academic Search

Using a dynamic flow method, the supercritical carbon dioxide (SC?CO2) solubilities of two series of symmetrically substituted alkylenediphosphonic acids, bearing 2?ethylhexyl and 3?trimethylsilyl?1?propyl ester groups, respectively, were determined as a function of the number of methylene groups separating the two phosphorus atoms. An even–odd effect, similar to that observed previously for the aggregation of these compounds in nonpolar diluents, was

Daniel R. McAlister; Mark L. Dietz; Dominique Stepinski; Peter R. Zalupski; Julie A. Dzielawa; R. E. Barrans Jr; J. N. Hess; A. W. Herlinger

2005-01-01

134

Effects of tris(1,3-dichloro-2-propyl) phosphate and tris(1-chloropropyl) phosphate on cytotoxicity and mRNA expression in primary cultures of avian hepatocytes and neuronal cells.  

PubMed

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and tris(1-chloropropyl) phosphate (TCPP) belong to a group of chemicals collectively known as triester organophosphate flame retardants (OPFRs). OPFRs are used in a wide range of consumer products and have been detected in biota, including free-living avian species; however, data on toxicological and molecular effects of exposure are limited. An in vitro screening approach was used to compare concentration-dependent effects of TDCPP and TCPP on cytotoxicity and messenger RNA (mRNA) expression in cultured hepatocytes and neuronal cells derived from embryonic chickens. TDCPP was toxic to hepatocytes (LC?? = 60.3 ± 45.8?M) and neuronal cells (LC?? = 28.7 ± 19.1?M), whereas TCPP did not affect viability in either cell type up to the highest concentration administered, 300?M. Real-time reverse transcription-PCR revealed alterations in mRNA abundance of genes associated with phase I and II metabolism, the thyroid hormone (TH) pathway, lipid regulation, and growth in hepatocytes. None of the transcripts measured in neuronal cells (D2, D3, RC3, and Oct-1) varied in response to TDCPP or TCPP exposure. Exposure to ? 10?M TDCPP and TCPP resulted in significant upregulation of CYP2H1 (4- to 8-fold), CYP3A37 (13- to 127-fold), and UGT1A9 (3.5- to 7-fold) mRNA levels. Transthyretin was significantly downregulated more than twofold by TCPP at 100?M; however, TDCPP did not alter its expression. Liver fatty acid-binding protein, TH-responsive spot 14-?, and insulin-like growth factor-1 were all downregulated (up to 10-fold) in hepatocytes exposed to ? 0.01?M TDCPP and TCPP. Taken together, our results indicate that genes associated with xenobiotic metabolism, the TH pathway, lipid regulation, and growth are vulnerable to TDCPP and TCPP administration in cultured avian hepatocytes. The mRNA expression data were similar to those from a previous study with hexabromocyclododecane. PMID:22268003

Crump, Doug; Chiu, Suzanne; Kennedy, Sean W

2012-03-01

135

The use of fatty acid esters to enhance free acid sophorolipid synthesis.  

PubMed

Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate, Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid sophorolipids (SLs). Fed-batch fermentations of Candida bombicola resulted in SL yields of 46 +/- 4 g/l, 42 +/- 7 g/l and 18 +/- 6 g/l from Me-Soy, Et-Soy, and Pro-Soy, respectively. Liquid chromatography with atmospheric pressure ionization mass spectrometry (LC/API-MS) showed that Me-Soy resulted in 71% open-chain SLs with 59% of those molecules remaining esterified at the carboxyl end of the fatty acids. Et-Soy and Pro-Soy resulted in 43% and 80% open-chain free-acid SLs, respectively (containing linoleic acid and oleic acid as the principal fatty acid species linked to the sophorose sugar at the omega-1 position), with no evidence of residual esterification. PMID:16555009

Ashby, Richard D; Solaiman, Daniel K Y; Foglia, Thomas A

2006-02-01

136

Automated GC-MS analysis of free amino acids in biological fluids.  

PubMed

A gas chromatography-mass spectrometry (GC-MS) method was developed for the quantitative analysis of free amino acids as their propyl chloroformate derivatives in biological fluids. Derivatization with propyl chloroformate is carried out directly in the biological samples without prior protein precipitation or solid-phase extraction of the amino acids, thereby allowing automation of the entire procedure, including addition of reagents, extraction and injection into the GC-MS. The total analysis time was 30 min and 30 amino acids could be reliably quantified using 19 stable isotope-labeled amino acids as internal standards. Limits of detection (LOD) and lower limits of quantification (LLOQ) were in the range of 0.03-12 microM and 0.3-30 microM, respectively. The method was validated using a certified amino acid standard and reference plasma, and its applicability to different biological fluids was shown. Intra-day precision for the analysis of human urine, blood plasma, and cell culture medium was 2.0-8.8%, 0.9-8.3%, and 2.0-14.3%, respectively, while the inter-day precision for human urine was 1.5-14.1%. PMID:18603486

Kaspar, Hannelore; Dettmer, Katja; Gronwald, Wolfram; Oefner, Peter J

2008-07-15

137

Bis(?-nitrato-?2 O:O)bis­{[1,2-bis­(diiso­propyl­phosphan­yl)-1,2-dicarba-closo-dodeca­borane-?2 P,P?]silver(I)} di­chloro­methane disolvate  

PubMed Central

The title compound, [Ag2(NO3)2(C14H38B10P2)2]·2CH2Cl2, was synthesized by the reaction of 1,2-bis­(diiso­propyl­phosphan­yl)-1,2-dicarba-closo-dodeca­borane with AgNO3. The resulting dinuclear molecule has crystallographically imposed inversion symmetry. The diiso­propyl­phosphanyl-closo-carborane ligand is coordin­ated in a bidentate manner to the AgI atom through the two P atoms. The distorted tetra­hedral coordination of the metal is completed by two O atoms of two bridging nitrate anions. The separation between the two AgI atoms is 3.8913?(5)?Å. C—H?O hydrogen bonds are observed involving the dichloromethane solvent molecule and the nitrate anion. PMID:24826102

Yang, Liguo

2014-01-01

138

Effect of active hydroxyl groups on the interfacial bond strength of titanium with segmented polyurethane through gamma-mercapto propyl trimethoxysilane.  

PubMed

The objective of this study was to investigate the effect of active hydroxyl groups on a titanium (Ti) surface on the bond strength between Ti and segmented polyurethane (SPU) composite through gamma-mercapto propyl trimethoxysilane (gamma-MPS). Active hydroxyl groups on Ti surface oxide were controlled by immersion in hydrogen peroxide (H2O2) with different lengths of immersion time, and the resulting concentrations of active hydroxyl groups were evaluated using a zinc-complex substitution technique. For the H2O2-treated Ti, it was characterized using X-ray photoelectron spectroscopy and scanning electron spectroscopy. For the bond strength of Ti/ gamma-MPS/SPU interface, it was determined using a shear bond test. Results showed that the bond strength increased with increase in the concentration of active hydroxyl groups. In terms of durability after immersion in water at 310 K for 30 days, it was found that bond strength was improved with increase in active hydroxyl groups. Based on the results obtained, active hydroxyl groups on the surface oxide film were clearly one of the causes governing the interfacial bond strength. PMID:18309616

Sakamoto, Harumi; Hirohashi, Yohei; Saito, Haruka; Doi, Hisashi; Tsutsumi, Yusuke; Suzuki, Yoshiaki; Noda, Kazuhiko; Hanawa, Takao

2008-01-01

139

Role of 2-hexyl, 5-propyl resorcinol production by Pseudomonas chlororaphis PCL1606 in the multitrophic interactions in the avocado rhizosphere during the biocontrol process.  

PubMed

Different bacterial traits can contribute to the biocontrol of soilborne phytopathogenic fungus. Among others, (1) antagonism, (2) competition for nutrients and niches, (3) induction of systemic resistance of the plants and (4) predation and parasitism are the most studied. Pseudomonas chlororaphis PCL1606 is an antagonistic rhizobacterium that produces the antifungal metabolite 2-hexyl, 5-propyl resorcinol (HPR). This bacterium can biologically control the avocado white root rot caused by Rosellinia necatrix. Confocal laser scanning microscopy of the avocado rhizosphere revealed that this biocontrol bacterium and the fungal pathogen compete for the same niche and presumably also for root exudate nutrients. The use of derivative mutants in the geners related to HPR biosynthesis (dar genes) revealed that the lack of HPR production by P. chlororaphis PCL1606 negatively influences the bacterial colonisation of the avocado root surface. Microscopical analysis showed that P. chlororaphis PCL1606 closely interacts and colonises the fungal hyphae, which may represent a novel biocontrol mechanism in this pseudomonad. Additionally, the presence of HPR-producing biocontrol bacteria negatively affects the ability of the fungi to infect the avocado root. HPR production negatively affects hyphal growth, leading to alterations in the R. necatrix physiology visible under microscopy, including the curling, vacuolisation and branching of hyphae, which presumably affects the colonisation and infection abilities of the fungus. This study provides the first report of multitrophic interactions in the avocado rhizosphere, advancing our understanding of the role of HPR production in those interactions. PMID:24641321

Calderón, Claudia E; de Vicente, Antonio; Cazorla, Francisco M

2014-07-01

140

Toxicogenomic responses of zebrafish embryos/larvae to tris(1,3-dichloro-2-propyl) phosphate (TDCPP) reveal possible molecular mechanisms of developmental toxicity.  

PubMed

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is frequently present in indoor dust and can be detected in human milk. In order to evaluate the effects of TDCPP on vertebrate development, zebrafish embryos/larvae were used as an animal model to examine developmental phenotypes and explore possible mechanisms of toxicity by employing microarrays and iTRAQ labeling quantitative proteomics. The results demonstrated that treatment with TDCPP (3 ?M) from 0.75 h postfertilization (hpf) inhibited cell rearrangement at 4 hpf, caused delay in epiboly at 5.7 and 8.5 hpf, and led to abnormal development (e.g., short tail, reduced body size) and lethality between 14 and 45 hpf, which might be related with altered expression of genes regulating embryogenesis. Furthermore, trunk curvature was observed as the main phenotype in 96 hpf zebrafish larvae exposed to 1 or 3 ?M TDCPP, possibly by changing somite formation and expression of proteins related to fast muscle and cartilage development. Collectively, our results suggest that exposure to TDCPP causes developmental toxicity in vertebrates and warrant the need for studies to evaluate the potential health risks of TDCPP to developing human embryos/infants/children, due to its frequent presence in indoor dust and potential for human exposure. PMID:23919627

Fu, Jie; Han, Jian; Zhou, Bingsheng; Gong, Zhiyuan; Santos, Eduarda M; Huo, Xiaojing; Zheng, Weiling; Liu, Hongling; Yu, Hongxia; Liu, Chunsheng

2013-09-17

141

The mechanical properties of the ultra high molecular weight polyethylene grafted with 3-dimethy (3-(N-methacryamido) propyl) ammonium propane sulfonate.  

PubMed

Ultra-high molecular weight polyethylene (UHMWPE) powder was modified with a zwitterion monomer with good biocompatibility of MPDSAH (3-dimethy (3-(N-methacryamido) propyl) ammonium propane sulfonate) by UV irradiation and then hot pressed. The microstructure and mechanical properties of modified UHMWPE are investigated. The results show that the structure of powder and bulk materials has been changed. The modified powders have more filaments than that of untreated. The surface of modified bulk materials is more rough and displays the granular protuberances which have the random loose arrangement compared with untreated UHMWPE. The crystallinity, uniaxial tensile and compressive properties decreased after grafting. Ultimate elongations decrease with the increase of the monomer concentration and are higher than 300% which is recommended by ASTM and ISO except the sample with 0.45mol/L MPDSAH. The friction coefficient of modified UHMWPE is lower than that of the untreated UHMWPE and it decreases gradually with the increase of monomer concentration. The wear rates have been decreased and the wear resistance has been improved under saline and distilled water lubrication. PMID:24727573

Deng, Yaling; Xiong, Dangsheng; Wang, Kun

2014-07-01

142

Reaction rate coefficients of OH radicals and Cl atoms with ethyl propanoate, n-propyl propanoate, methyl 2-methylpropanoate, and ethyl n-butanoate.  

PubMed

Kinetics of the reactions of OH radicals and Cl atoms with four saturated esters have been investigated. Rate coefficients for the gas-phase reactions of OH radicals with ethyl propanoate (k(1)), n-propyl propanoate (k(2)), methyl 2-methylpropanoate (k(3)), and ethyl n-butanoate (k(4)) were measured using a conventional relative rate method and the pulsed laser photolysis-laser induced fluorescence technique. At (296 +/- 2) K, the rate coefficients obtained by the two methods were in good agreement. Significant curvatures in the Arrhenius plots have been observed in the temperature range 243-372 K for k(1), k(3), and k(4). The rate coefficients for the reactions of the four esters with Cl atoms were determined using the relative rate method at (296 +/- 2) K and atmospheric pressure. The values obtained are presented, compared with the literature values when they exist, and discussed. Reactivity trends and atmospheric implications for these esters are also presented. PMID:19746921

Cometto, Pablo M; Daële, Véronique; Idir, Mahmoud; Lane, Silvia I; Mellouki, Abdelwahid

2009-10-01

143

Addition of a propyl gallate-based procoagulant to a fibrin bandage improves hemostatic performance in a swine arterial bleeding model.  

PubMed

Fibrin bandages manufactured by Nycomed Austria (TC-S) were modified by the addition of Hemostyptin (HS), a proprietary platelet-activating reagent containing propyl gallate. HS was added as an additional layer to TC-S fibrin bandages and the bandages were tested for hemostatic efficacy in a swine femoral artery bleeding model. Injuries were treated with a TC-S+HS bandage preparation using HS lyophilized onto a bandage surface that was then attached to the fibrin dressing. This preparation qualitatively and quantitatively exhibited more robust blood clotting at the surgical site than the control bandages. TC-S+HS bandages were more effective than control bandages with a difference in blood loss of 251.8+/-66.5 g for TC-S bandage alone, n=12 vs. 121+/-40.7 g, n=13 for the TC-S+HS bandage, P=0.05. Bleeding times were shortened for animals treated with the HS fortified bandages and residual platelets counts in these animals were higher. PMID:12676195

Rothwell, Stephen W; Fudge, James M; Chen, Wan-Keung; Reid, Thomas J; Krishnamurti, Chitra

2002-12-15

144

Is the PentaBDE Replacement, Tris (1,3-dichloro-2-propyl) Phosphate (TDCPP), a Developmental Neurotoxicant? Studies in PC12 Cells  

PubMed Central

Organophosphate flame retardants (OPFRs) are used as replacements for the commercial PentaBDE mixture that was phased out in 2004. OPFRs are ubiquitous in the environment and detected at high concentrations in residential dust, suggesting widespread human exposure. OPFRs are structurally similar to neurotoxic organophosphate pesticides, raising concerns about exposure and toxicity to humans. This study evaluated the neurotoxicity of tris (1,3-dichloro-2-propyl) phosphate (TDCPP) compared to the organophosphate pesticide, chlorpyrifos (CPF), a known developmental neurotoxicant. We also tested the neurotoxicity of three structurally similar OPFRs, tris (2-chloroethyl) phosphate (TCEP), tris (1-chloropropyl) phosphate (TCPP), and tris (1,3-dibromopropyl) phosphate (TDBPP), and 2,2?,4,4?-tetrabromodiphenyl ether (BDE-47), a major component of PentaBDE. Using undifferentiated and differentiating PC12 cells, changes in DNA synthesis, oxidative stress, differentiation into dopaminergic or cholinergic neurophenotypes, cell number, cell growth and neurite growth were assessed. TDCPP displayed concentration-dependent neurotoxicity, often with effects equivalent to or greater than equimolar concentrations of CPF. TDCPP inhibited DNA synthesis, and all OPFRs decreased cell number, and altered neurodifferentiation. Although TDCPP elevated oxidative stress, there was no adverse effect on cell viability or growth. TDCPP and TDBPP promoted differentiation into both neuronal phenotypes, while TCEP and TCPP promoted only the cholinergic phenotype. BDE-47 had no effect on cell number, cell growth or neurite growth. Our results demonstrate that different OPFRs show divergent effects on neurodifferentiation, suggesting the participation of multiple mechanisms of toxicity. Additionally, these data suggest that OPFRs may affect neurodevelopment with similar or greater potency compared to known and suspected neurotoxicants. PMID:21255595

Dishaw, Laura V.; Powers, Christina M.; Ryde, Ian T.; Roberts, Simon C.; Seidler, Frederic J.; Slotkin, Theodore A.; Stapleton, Heather M.

2011-01-01

145

High-affinity dextromethorphan and (+)-3-(-3-hydroxyphenyl)-N-(1-propyl)piperidine binding sites in rat brain. Allosteric effects of ropizine.  

PubMed

Dextromethorphan (DM) binds to high- and low-affinity sites in the rat brain. The high-affinity DM binding is inhibited by nonnarcotic antitussives, opipramol and sigma ligands with nanomolar affinities. Computer-assisted modeling of homologous and heterologous competition studies between DM and (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [(+)-3-PPP] were performed at pH 8.4. These experiments confirmed the existence of the common high-affinity DM1/sigma 1 site (R1) for which DM and (+)-3-PPP have Kd values of 20 and 10 nM, respectively. DM also binds to a second high-affinity site (R2, Kd, 20 nM) for which (+)-3-PPP has only micromolar affinity. Similarly, (+)-3-PPP binds to another high-affinity site (R3, Kd, 60 nM) for which DM has micromolar affinity. The common high-affinity DM1/sigma 1 site is allosterically modulated by the anticonvulsant ropizine, and is (+)-pentazocine sensitive, as is the homologous site in the guinea pig. However, in the rat the common DM1/sigma 1 site is 10 times smaller than in the guinea pig. This explains the apparently different effects of the allosteric modifiers in both species. The multiplicity of binding sites for DM and (+)-3-PPP resolved in this investigation will help to establish the physiological role and the pharmacological potential of the different sites. Meanwhile, the pharmacological effects of DM and sigma ligands cannot be summarily attributed to any particular binding site or receptor. This investigation also demonstrates that the use of multiple labeled and unlabeled ligands, combined with computer-assisted modeling, is essential to resolve multiple binding sites with similar affinities and to characterize the complex effects of allosteric modifiers. PMID:1312173

Klein, M; Musacchio, J M

1992-03-01

146

Is the PentaBDE replacement, tris (1,3-dichloro-2-propyl) phosphate (TDCPP), a developmental neurotoxicant? Studies in PC12 cells  

SciTech Connect

Organophosphate flame retardants (OPFRs) are used as replacements for the commercial PentaBDE mixture that was phased out in 2004. OPFRs are ubiquitous in the environment and detected at high concentrations in residential dust, suggesting widespread human exposure. OPFRs are structurally similar to neurotoxic organophosphate pesticides, raising concerns about exposure and toxicity to humans. This study evaluated the neurotoxicity of tris (1,3-dichloro-2-propyl) phosphate (TDCPP) compared to the organophosphate pesticide, chlorpyrifos (CPF), a known developmental neurotoxicant. We also tested the neurotoxicity of three structurally similar OPFRs, tris (2-chloroethyl) phosphate (TCEP), tris (1-chloropropyl) phosphate (TCPP), and tris (2,3-dibromopropyl) phosphate (TDBPP), and 2,2 Prime ,4,4 Prime -tetrabromodiphenyl ether (BDE-47), a major component of PentaBDE. Using undifferentiated and differentiating PC12 cells, changes in DNA synthesis, oxidative stress, differentiation into dopaminergic or cholinergic neurophenotypes, cell number, cell growth and neurite growth were assessed. TDCPP displayed concentration-dependent neurotoxicity, often with effects equivalent to or greater than equimolar concentrations of CPF. TDCPP inhibited DNA synthesis, and all OPFRs decreased cell number and altered neurodifferentiation. Although TDCPP elevated oxidative stress, there was no adverse effect on cell viability or growth. TDCPP and TDBPP promoted differentiation into both neuronal phenotypes, while TCEP and TCPP promoted only the cholinergic phenotype. BDE-47 had no effect on cell number, cell growth or neurite growth. Our results demonstrate that different OPFRs show divergent effects on neurodifferentiation, suggesting the participation of multiple mechanisms of toxicity. Additionally, these data suggest that OPFRs may affect neurodevelopment with similar or greater potency compared to known and suspected neurotoxicants.

Dishaw, Laura V. [Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States)] [Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States); Powers, Christina M. [Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710 (United States)] [Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710 (United States); Ryde, Ian T.; Roberts, Simon C. [Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States)] [Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States); Seidler, Frederic J.; Slotkin, Theodore A. [Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710 (United States)] [Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710 (United States); Stapleton, Heather M., E-mail: heather.stapleton@duke.edu [Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States)

2011-11-15

147

Comparative study of the hydrolytic metabolism of methyl-, ethyl-, propyl-, butyl-, heptyl- and dodecylparaben by microsomes of various rat and human tissues.  

PubMed

Hydrolytic metabolism of methyl-, ethyl-, propyl-, butyl-, heptyl- and dodecylparaben by various tissue microsomes and plasma of rats, as well as human liver and small-intestinal microsomes, was investigated and the structure-metabolic activity relationship was examined. Rat liver microsomes showed the highest activity toward parabens, followed by small-intestinal and lung microsomes. Butylparaben was most effectively hydrolyzed by the liver microsomes, which showed relatively low hydrolytic activity towards parabens with shorter and longer alkyl side chains. In contrast, small-intestinal microsomes exhibited relatively higher activity toward longer-side-chain parabens, and showed the highest activity towards heptylparaben. Rat lung and skin microsomes showed liver-type substrate specificity. Kidney and pancreas microsomes and plasma of rats showed small-intestinal-type substrate specificity. Liver and small-intestinal microsomal hydrolase activity was completely inhibited by bis(4-nitrophenyl)phosphate, and could be extracted with Triton X-100. Ces1e and Ces1d isoforms were identified as carboxylesterase isozymes catalyzing paraben hydrolysis by anion exchange column chromatography of Triton X-100 extract from liver microsomes. Ces1e and Ces1d expressed in COS cells exhibited significant hydrolase activities with the same substrate specificity pattern as that of liver microsomes. Small-intestinal carboxylesterase isozymes Ces2a and Ces2c expressed in COS cells showed the same substrate specificity as small-intestinal microsomes, being more active toward longer-alkyl-side-chain parabens. Human liver microsomes showed the highest hydrolytic activity toward methylparaben, while human small-intestinal microsomes showed a broadly similar substrate specificity to rat small-intestinal microsomes. Human CES1 and CES2 isozymes showed the same substrate specificity patterns as human liver and small-intestinal microsomes, respectively. PMID:23742084

Ozaki, Hitomi; Sugihara, Kazumi; Watanabe, Yoko; Fujino, Chieri; Uramaru, Naoto; Sone, Tomomichi; Ohta, Shigeru; Kitamura, Shigeyuki

2013-12-01

148

Effects of tris(1,3-dichloro-2-propyl) phosphate and triphenyl phosphate on receptor-associated mRNA expression in zebrafish embryos/larvae.  

PubMed

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate (TPP) are frequently detected in biota, including fish. However, knowledge of the toxicological and molecular effects of these currently used flame retardants is limited. In the present study, an in vivo screening approach was developed to evaluate effects of TDCPP and TPP on developmental endpoints and receptor-associated expression of mRNA in zebrafish embryos/larvae. Exposure to TDCPP or TPP resulted in significantly smaller rates of hatching and survival, in dose- and time-dependent manners. The median lethal concentration (LC(50)) was 7.0 mg/L for TDCPP and 29.6 mg/L for TPP at 120 hour post-fertilization (hpf). Real-time PCR revealed alterations in expression of mRNAs involved in aryl hydrocarbon receptors (AhRs)-, peroxisome proliferator-activated receptor alpha (PPAR?)-, estrogenic receptors (ERs)-, thyroid hormone receptor alpha (TR?)-, glucocorticoid receptor (GR)-, and mineralocorticoid receptor (MR)-centered gene networks. Exposure to positive control chemicals significantly altered abundances of mRNA in corresponding receptor-centered gene networks, a result that suggests that it is feasible to use zebrafish embryos/larvae to evaluate effects of chemicals on mRNA expression in these gene networks. Exposure to TDCPP altered transcriptional profiles in all six receptor-centered gene networks, thus exerting multiple toxic effects. TPP was easily metabolized and its potency to change expression of mRNA involved in receptor-centered gene networks was weaker than that of TDCPP. The PPAR?- and TR?-centered gene networks might be the primary pathways affected by TPP. Taken together, these results demonstrated that TDCPP and TPP could alter mRNA expression of genes involved in the six receptor-centered gene networks in zebrafish embryos/larvae, and TDCPP seemed to have higher potency in changing the mRNA expression of these genes. PMID:23306105

Liu, Chunsheng; Wang, Qiangwei; Liang, Kang; Liu, Jingfu; Zhou, Bingsheng; Zhang, Xiaowei; Liu, Hongling; Giesy, John P; Yu, Hongxia

2013-03-15

149

Is the PentaBDE replacement, tris (1,3-dichloro-2-propyl) phosphate (TDCPP), a developmental neurotoxicant? Studies in PC12 cells.  

PubMed

Organophosphate flame retardants (OPFRs) are used as replacements for the commercial PentaBDE mixture that was phased out in 2004. OPFRs are ubiquitous in the environment and detected at high concentrations in residential dust, suggesting widespread human exposure. OPFRs are structurally similar to neurotoxic organophosphate pesticides, raising concerns about exposure and toxicity to humans. This study evaluated the neurotoxicity of tris (1,3-dichloro-2-propyl) phosphate (TDCPP) compared to the organophosphate pesticide, chlorpyrifos (CPF), a known developmental neurotoxicant. We also tested the neurotoxicity of three structurally similar OPFRs, tris (2-chloroethyl) phosphate (TCEP), tris (1-chloropropyl) phosphate (TCPP), and tris (2,3-dibromopropyl) phosphate (TDBPP), and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), a major component of PentaBDE. Using undifferentiated and differentiating PC12 cells, changes in DNA synthesis, oxidative stress, differentiation into dopaminergic or cholinergic neurophenotypes, cell number, cell growth and neurite growth were assessed. TDCPP displayed concentration-dependent neurotoxicity, often with effects equivalent to or greater than equimolar concentrations of CPF. TDCPP inhibited DNA synthesis, and all OPFRs decreased cell number and altered neurodifferentiation. Although TDCPP elevated oxidative stress, there was no adverse effect on cell viability or growth. TDCPP and TDBPP promoted differentiation into both neuronal phenotypes, while TCEP and TCPP promoted only the cholinergic phenotype. BDE-47 had no effect on cell number, cell growth or neurite growth. Our results demonstrate that different OPFRs show divergent effects on neurodifferentiation, suggesting the participation of multiple mechanisms of toxicity. Additionally, these data suggest that OPFRs may affect neurodevelopment with similar or greater potency compared to known and suspected neurotoxicants. PMID:21255595

Dishaw, Laura V; Powers, Christina M; Ryde, Ian T; Roberts, Simon C; Seidler, Frederic J; Slotkin, Theodore A; Stapleton, Heather M

2011-11-01

150

Complete detoxification of tris(1,3-dichloro-2-propyl) phosphate by mixed two bacteria, Sphingobium sp. strain TCM1 and Arthrobacter sp. strain PY1.  

PubMed

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP), a flame retardant, is regarded as a potentially toxic and persistent environmental contaminant. We previously isolated a TDCPP-degrading bacterium, Sphingobium sp. strain TCM1, which, however, produced a toxic metabolite: 1,3-dichloro-2-propanol (1,3-DCP). This study was undertaken to develop a technique for complete TDCPP detoxification using strain TCM1 with a 1,3-DCP-degrading bacterium, Arthrobacter sp. strain PY1. For efficient detoxification, we designed a resting cell system and examined the effect of freezing and lyophilization treatments for preparation of their resting cells. Results show that treatments had no marked adverse effect on their activities. The TDCPP dephosphorylation by TCM1 resting cells was optimal at 30°C and pH 8.5. Also, 1,3-DCP dehalogenation by strain PY1 resting cells was optimal at 35°C and pH 9.5. Under those respective conditions, the activities were 2.48 ?mol h?¹·OD????¹ for TDCPP and 0.95 ?mol h?¹·OD????¹ for 1,3-DCP. Based on these results, we set the reaction temperature to 30°C and pH to 9.0. Then we examined the detoxification of 50 ?M TDCPP using mixed resting cells at a final OD(660) of 0.05 for strain TCM1 and 0.2 for strain PY1. In these conditions, TDCPP was eliminated after 1h, but some of the resulting 1,3-DCP remained at a constant level. The increase in strain PY1 cells to a final OD??? of 4.0 decreased the TDCPP dephosphorylation rate of strain TCM1 cells but achieved complete detoxification of TDCPP during 12 h of reaction. PMID:21956155

Takahashi, Shouji; Obana, Yuki; Okada, Shohei; Abe, Katsumasa; Kera, Yoshio

2012-01-01

151

Swellable molecularly imprinted polyN-(N-propyl)acrylamide particles for detection of emerging organic contaminants using surface plasmon resonance spectroscopy.  

PubMed

Lightly crosslinked theophylline imprinted polyN-(N-propyl)acrylamide particles (ca. 300nm in diameter) that are designed to swell and shrink as a function of analyte concentration in aqueous media were spin coated onto a gold surface. The nanospheres responded selectively to the targeted analyte due to molecular imprinting. Chemical sensing was based on changes in the refractive index of the imprinted particles that accompanied swelling due to binding of the targeted analyte, which was detected using surface plasmon resonance (SPR) spectroscopy. Because swelling leads to an increase in the percentage of water in the polymer, the refractive index of the polymer nanospheres decreased as the particles swelled. In the presence of aqueous theophylline at concentrations as low as 10(-6)M, particle swelling is both pronounced and readily detectable. The full scale response of the imprinted particles to template occurs in less than 10min. Swelling is also reversible and independent of the ionic strength of the solution in contact with the polymer. Replicate precision is less than 10(-4) RI units. By comparison, there is no response to caffeine which is similar in structure to theophylline at concentrations as high as 1x10(-2)M. Changes in the refractive index of the imprinted polymer particles, as low as 10(-4) RI units could be readily detected. A unique aspect of the prepared particles is the use of light crosslinking rather than heavy crosslinking. This is a significant development as it indicates that heavy crosslinking is not entirely necessary for selectivity in molecular imprinting with polyacrylamides. PMID:19071722

Lavine, Barry K; Westover, David J; Kaval, Necati; Mirjankar, Nikhil; Oxenford, Leah; Mwangi, George K

2007-05-15

152

Simultaneous multicomponent spectrophotometric monitoring of methyl and propyl parabens using multivariate statistical methods after their preconcentration by robust ionic liquid-based dispersive liquid-liquid microextraction.  

PubMed

A powerful and efficient signal-preprocessing technique that combines local and multiscale properties of the wavelet prism with the global filtering capability of orthogonal signal correction (OSC) is applied for pretreatment of spectroscopic data of parabens as model compounds after their preconcentration by robust ionic liquid-based dispersive liquid-liquid microextraction method (IL-DLLME). In the proposed technique, a mixture of a water-immiscible ionic liquid (as extraction solvent) [Hmim][PF6] and disperser solvent is injected into an aqueous sample solution containing one of the IL's ions, NaPF6, as extraction solvent and common ion source. After preconcentration, the absorbance of the extracted compounds was measured in the wavelength range of 200-700 nm. The wavelet orthogonal signal correction with partial least squares (WOSC-PLS) method was then applied for simultaneous determination of each individual compound. Effective parameters, such as amount of IL, volume of the disperser solvent and amount of NaPF6, were inspected by central composite design to identify the most important parameters and their interactions. The effect of pH on the sensitivity and selectivity was studied according to the net analyte signal (NAS) for each component. Under optimum conditions, enrichment factors of the studied compounds were 75 for methyl paraben (MP) and 71 for propyl paraben (PP). Limits of detection for MP and PP were 4.2 and 4.8 ng mL(-)(1), respectively. The root mean square errors of prediction for MP and PP were 0.1046 and 0.1275 ?g mL(-)(1), respectively. The practical applicability of the developed method was examined using hygienic, cosmetic, pharmaceutical and natural water samples. PMID:24317257

Khani, Rouhollah; Ghasemi, Jahan B; Shemirani, Farzaneh

2014-03-25

153

[Synthesis of new mandelic acid derivatives with preservative action. Synthesis and acute toxicity study].  

PubMed

Starting from the antiseptic action of DL mandelic acid, there were synthesized a series of esters of the mandelic acid, esters which could have preservative action. This study present the synthesis, structure validation and the acute toxicity study, for the new synthesized compounds. The esters were obtained by acylating 4-hydroxybenzoic acid propyl, ethyl, methyl esters and salicylic acid with the DL mandelic chloride (that was protected initially by the hydroxylic group). The structure of the synthesized compounds was confirmed by quantitative elemental analysis and RMN 1H spectral measurements. The acute toxicity was determined for two of the esters, who proved to had a preservative action (previously studied) and indicated that these esters have a small toxicity. PMID:15688782

Stan, C?t?lina; N?stase, V; Pavelescu, M; Vasile, Cornelia; Dumitrache, M; Gherase, Floren?a; N?stas?, Veronica

2004-01-01

154

Chiral analysis of anti-acquired immunodeficiency syndrome drug, 9-(R)-[2-(phosphonomethoxy)propyl]adenine (tenofovir), and related antiviral acyclic nucleoside phosphonates by CE using beta-CD as chiral selector.  

PubMed

A new CZE method has been developed for chiral analysis of an important anti-acquired immunodeficiency syndrome drug, 9-(R)-[2-(phosphonomethoxy)propyl]adenine ((R)-PMPA, tenofovir), and six related antiviral acyclic nucleoside phosphonates using beta-CD as a chiral selector. The influence of the composition, concentration and pH of the BGE and the type and concentration of chiral selector on enantiomer resolution was investigated. Complete separations of (R,S)-enantiomers of PMPA with very good resolution (R(s)=1.50-3.64) were achieved within a short time (4-15 min) in 20-50 mM sodium borate or sodium tetraborate BGEs, pH 10.0, at 20 mg/mL concentration of beta-CD. (R,S)-enantiomers of five similar PMPA analogs containing purine bases (adenine, diaminopurine or guanine) and hydroxyl or fluor substituents at C3 carbon atom of propyl chain were baseline separated within 10-17 min in 35 mM sodium tetraborate BGE, pH 10.0, at 20 mg/mL beta-CD concentration. Another important antiviral used by acquired immunodeficiency syndrome patients, derived from pyrimidine base cytosine, 1-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine (cidofovir), and the (R)-enantiomer of this drug were successfully separated in 50 mM sodium tetraborate BGE, pH 10.5, at 20 mg/mL beta-CD concentration within 45 min. Using the UV-absorption detection at 206 nm, the concentration detection limits of the analyzed acyclic nucleoside phosphonates were determined in the submicromolar to micromolar range (0.15-2.51 microg/mL level). PMID:19544492

Solínová, Veronika; Kasicka, Václav; Sázelová, Petra; Holý, Antonín

2009-06-01

155

Evaluation of in vivo wound-healing potential of 2-[4-(2,4-dimethoxy-benzoyl)-phenoxy]-1-[4-(3-piperidin-4-yl-propyl)-piperidin-1-yl]-ethanone derivatives  

Microsoft Academic Search

Series of 2-[4-(2,4-dimethoxy-benzoyl)-phenoxy]-1-[4-(3-piperidin-4-yl-propyl)-piperidin-1-yl]-ethanone derivatives 9(a–d) and 10(a–d) were synthesized in good yield. The synthesized compounds were characterized by 1H NMR, LC–MS, FTIR and elemental analysis. All the compounds were screened for in vivo wound-healing activity by incision and dead space wound models on Swiss albino rats. Significant wound healing was observed in 10b and 10d treated groups as also the

K. Vinaya; H. Raja Naika; C. S. Ananda Kumar; S. B. Benaka Prasad; S. Chandrappa; S. R. Ranganatha; V. Krishna; K. S. Rangappa

2009-01-01

156

Evaluation of LY163443, 1-[2-hydroxy-3-propyl-4-{[4-(1H-tetrazol-5-ylmethyl)phenoxy]methyl}phenyl]ethanone, as a pharmacologic antagonist of leukotrienes D 4 and E 4  

Microsoft Academic Search

LY163443,1-[2-hydroxy-3-propyl-4-{[4-(1H-tetrazol-5-ylmethyl)-phenoxy]methyl}phenyl]ethanone, antagonized LTD4-induced contractions of guinea pig ileum, trachea, and lung parenchyma. Tracheal contractions to LTE4 were also inhibited by LY163443. The compound had minimal effect against ileal responses to LTC4 and parenchymal contractions to LTB4. Furthermore, LY163443.had little to no effect against contractions of isolated smooth muscles to histamine, bradykinin, PGF2a, carbachol, serotonin or U46619. LY163443, given by oral

Jerome H. Fleisch; Lynn E. Rinkema; Klaus D. Haisch; Doris McCullough; F. Patrick Carr; Robert D. Dillard

1986-01-01

157

Synthesis and comparison of two poly (methyl methacrylate-b-3-(trimethoxysilyl)propyl methacrylate)/SiO2 hybrids by "grafting-to" approach.  

PubMed

Two copolymer/SiO2 hybrids are prepared by growing SiO2 on the template of well -structured diblock copolymer PMMA-b-PMPS using a "grafting-to" approach. PMMA-b-PMPS is obtained by atom transfer radical polymerization (ATRP) of methyl methacrylate (PMMA) and 3-(trimethoxysilyl)propyl methacrylate (PMPS) using a brominated initiator end group termed 1H,1H,2H,2H-heptadecafluoro (F-Br) and a conventional initiator of ethyl 2-bromoisobutyrate (EBiB), respectively. The "grafting-to" approach is controlled at HCl for 24h by hydrolysis and condensation of Si(OCH3)3 groups in PMPS with tetraethyl orthosilicate (TEOS) to gain both hybrids of F-PMMA-b-PMPS/SiO2 (by F-Br initiator) and E-PMMA-b-PMPS/SiO2 (by EBIB initiator). Comparatively, a little amount of fluorine content provided by F-Br is able to tighten the size of self-assembled micelles, to improve wettability and the viscoelasticity of F-PMMA-b-PMPS film due to F-Br migrating onto the film surface. Therefore, the surface of F-PMMA-b-PMPS film is sufficiently hydrophobic (99° and ?f=2941Hz) than E-PMMA-b-PMPS film (94°and ?f=4820Hz), and the viscoelasticity of the adsorbed layer for F-PMMA-b-PMPS (?D/?f=-0.112) film is much harder than E-PMMA-b-PMPS/SiO2 (?D/?f=-0.071). On the other hand, the cross-linked silica in PMMA-b-PMPS/SiO2 could also increase water contact angels of films (100-107°) and decrease the water absorption (?f=704-798Hz). The influence on the viscoelasticity of the adsorbed layer by the fluorine group is much more obvious than the cross-linked silica, therefore F-PMMA-b-PMPS/SiO2 (?D/?f=-0.347) and F-PMMA-b-PMPS (?D/?f=-0.112) films have harder adsorbed layer than E-PMMA-b-PMPS/SiO2 (-0.071) and F-PMMA-b-PMPS films (-0.042). However, compared with a slightly improvement in thermo stability by F-Br, the cross-linked silica in PMMA-b-PMPS/SiO2 performs significantly improving thermal decomposition temperature at 300°C and 350°C. PMID:25127293

Huang, Hongpu; He, Ling; Huang, Kehan; Gao, Min

2014-11-01

158

Amino acids  

MedlinePLUS

Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

159

Phosphatidylcholine and dihydrocaffeic acid amide mixture enhanced the thermo-oxidative stability of canola oil.  

PubMed

Recently, we reported the synthesis of a series of dihydrocaffeic acid amides and evaluated their performance as antioxidants for frying applications using a model frying. In the present study, the possibility of a synergy between the amide, N-propyl-N-benzyl-3-(3,4 dihydroxyphenyl)propanamide (DCA) and phosphatidylcholine (PC) was explored in a 6-day actual frying operation. As measured by the amount of polar components (TPC), anisidine value (AnV), changes in fatty acid composition, residual tocopherol and hydroxynonenal (HNE), canola oil containing the formulated antioxidant was twice as stable compared to the regular unfortified oil. At the end of the frying period, the amount of HNE detected in regular canola oil and the fortified sample was at 5.7 and 2.5?g/g, respectively. Thus, the mixture containing phosphatidylcholine and dihydrocaffeic acid amide is a promising antioxidant for frying application. PMID:24360481

Aladedunye, Felix; Przybylski, Roman

2014-05-01

160

The Role of Excitatory Amino Acids and NMDA Receptors in Traumatic Brain Injury  

NASA Astrophysics Data System (ADS)

Brain injury induced by fluid percussion in rats caused a marked elevation in extracellular glutamate and aspartate adjacent to the trauma site. This increase in excitatory amino acids was related to the severity of the injury and was associated with a reduction in cellular bioenergetic state and intracellular free magnesium. Treatment with the noncompetitive N-methyl-D-aspartate (NMDA) antagonist dextrorphan or the competitive antagonist 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid limited the resultant neurological dysfunction; dextrorphan treatment also improved the bioenergetic state after trauma and increased the intracellular free magnesium. Thus, excitatory amino acids contribute to delayed tissue damage after brain trauma; NMDA antagonists may be of benefit in treating acute head injury.

Faden, Alan I.; Demediuk, Paul; Panter, S. Scott; Vink, Robert

1989-05-01

161

Studies on triazole derivatives as inhibitors for the corrosion of muntz metal in acidic and neutral solutions  

Microsoft Academic Search

The influence of few triazole derivatives namely, 4-amino-5-mercapto-3-methyl 1,2,4 triazole (AMMT), 4-amino-5-mercapto-3-methyl 1,2,4 triazole (AMET) and 4-amino-5-mercapto-3-propyl 1,2,4 triazole (AMPT) on the corrosion behavior of muntz metal (60Cu–40Zn) in acidic and neutral solutions has been studied using weight loss measurements and potentiodynamic polarization methods. Surface morphological examinations such as UV spectral analysis, XRD and SEM have also been carried out

L. John Berchmans; V. Sivan; S. Venkata Krishna Iyer

2006-01-01

162

Synthesis and antimicrobial activity of 1-benzhydryl-sulfonyl-4-(3-(piperidin-4-yl) propyl)piperidine derivatives against pathogens of Lycopersicon esculentum: a structure-activity evaluation study.  

PubMed

Several 1-benzhydryl-sulfonyl-4-(3-(piperidin-4-yl)propyl)piperidine derivatives 8(a-j) were prepared by the treatment of substituted benzhydryl chlorides with 4-(3-(piperidin-4-yl)propyl)piperidine followed by N-sulfonation with sulfonyl chlorides in the presence of dry methylene dichloride and triethyl amine. The synthesized compounds were characterized by (1)H-NMR, IR, and elemental analysis. All the synthesized compounds were evaluated in vitro for their efficacy as antimicrobial agents by artificial inoculation technique against standard strains of two important bacterial viz., Xanthomonas axonopodis pv. vesicatoria and Ralstonia solanacearum as well as and two fungal pathogens namely Alternaria solani and Fusarium solani of tomato plants. We have briefly investigated the structure-activity relation studies and reveal that the nature of substitutions on benzhydryl ring and sulfonamide ring influences the antibacterial activity. Among the synthesized new compounds 8b, 8d, 8g, 8h, 8i, and 8j were showed significant potent antimicrobial activities compared to the standard drugs chloramphenicol, mancozeb. PMID:19183874

Vinaya, K; Kavitha, R; Ananda Kumar, C S; Benaka Prasad, S B; Chandrappa, S; Deepak, S A; Nanjunda Swamy, S; Umesha, S; Rangappa, K S

2009-01-01

163

Theoretical investigations on the molecular structure, vibrational spectral, HOMO-LUMO and NBO analysis of 9-[3-(Dimethylamino)propyl]-2-trifluoro-methyl-9H-thioxanthen-9-ol  

NASA Astrophysics Data System (ADS)

The experimental FT-IR and FT-Raman spectra of 9-[3-(Dimethylamino)propyl]-2-trifluoro-methyl-9H-thioxanthen-9-ol have been recorded. Quantum chemical calculations of geometry and vibrational wavenumbers of 9-[3-(Dimethylamino)propyl]-2-trifluoro-methyl-9H-thioxanthen-9-ol are carried out theoretically. Four possible stable conformations of the title compound were determined. In terms of the conformational analysis, one of the most interesting structural features of the title compound is the intra molecular Osbnd H⋯N hydrogen bond. The barrier of planarity between the most stable and planar form is also predicted. The optimized geometrical parameters obtained by B3LYP method show a good agreement with XRD data. The difference between the observed and theoretical wavenumbers is very small. The complete assignments were performed on the basis of potential energy distribution of the vibrational modes calculated theoretically. The calculated HOMO and LUMO energies allow the calculation of atomic and molecular properties and they also showed that charge transfer occurs in the molecule. A detailed molecular picture of the title compound and its interactions were obtained from NBO analysis. As seen from the MEP map, negative potential regions are over the hydroxyl group and positive potential regions are over the methyl groups.

Mary, Y. Sheena; Panicker, C. Yohannan; Yamuna, T. S.; Siddegowda, M. S.; Yathirajan, H. S.; Al-Saadi, Abdulaziz A.; Van Alsenoy, Christian

2014-11-01

164

Crystal structures of trans-di­chlorido­tetra­kis­[1-(2,6-diiso­propyl­phen­yl)-1H-imidazole-?N 3]iron(II), trans-di­bromido­tetra­kis­[1-(2,6-diiso­propyl­phen­yl)-1H-imidazole-?N 3]iron(II) and trans-di­bromido­tetra­kis­[1-(2,6-diiso­propyl­phen­yl)-1H-imidazole-?N 3]iron(II) diethyl ether disolvate1  

PubMed Central

The title compounds, [FeCl2(C15H20N2)4], (I), [FeBr2(C15H20N2)4], (II), and [FeBr2(C15H20N2)4]·2C4H10O, (IIb), respectively, all have triclinic symmetry, with (I) and (II) being isotypic. The FeII atoms in each of the structures are located on an inversion center. They have octa­hedral FeX 2N4 (X = Cl and Br, respectively) coordination spheres with the FeII atom coordinated by two halide ions in a trans arrangement and by the tertiary N atom of four aryl­imidazole ligands [1-(2,6-diiso­propyl­phen­yl)-1H-imidazole] in the equatorial plane. In the two independent ligands, the benzene and imidazole rings are almost normal to one another, with dihedral angles of 88.19?(15) and 79.26?(14)° in (I), 87.0?(3) and 79.2?(3)° in (II), and 84.71?(11) and 80.58?(13)° in (IIb). The imidazole rings of the two independent ligand mol­ecules are inclined to one another by 70.04?(15), 69.3?(3) and 61.55?(12)° in (I), (II) and (IIb), respectively, while the benzene rings are inclined to one another by 82.83?(13), 83.0?(2) and 88.16?(12)°, respectively. The various dihedral angles involving (IIb) differ slightly from those in (I) and (II), probably due to the close proximity of the diethyl ether solvent mol­ecule. There are a number of C—H?halide hydrogen bonds in each mol­ecule involving the CH groups of the imidazole units. In the structures of compounds (I) and (II), mol­ecules are linked via pairs of C—H?halogen hydrogen bonds, forming chains along the a axis that enclose R 2 2(12) ring motifs. The chains are linked by C—H?? inter­actions, forming sheets parallel to (001). In the structure of compound (IIb), mol­ecules are linked via pairs of C—H?halogen hydrogen bonds, forming chains along the b axis, and the diethyl ether solvent mol­ecules are attached to the chains via C—H?O hydrogen bonds. The chains are linked by C—H?? inter­actions, forming sheets parallel to (001). In (I) and (II), the methyl groups of an isopropyl group are disordered over two positions [occupancy ratio = 0.727?(13):0.273?(13) and 0.5:0.5, respectively]. In (IIb), one of the ethyl groups of the diethyl ether solvent mol­ecule is disordered over two positions (occupancy ratio = 0.5:0.5). PMID:25249858

Mafua, Roger; Jenny, Titus; Labat, Gael; Neels, Antonia; Stoeckli-Evans, Helen

2014-01-01

165

Crystal structures of trans-di-chlorido-tetra-kis-[1-(2,6-diiso-propyl-phen-yl)-1H-imidazole-?N (3)]iron(II), trans-di-bromido-tetra-kis-[1-(2,6-diiso-propyl-phen-yl)-1H-imidazole-?N (3)]iron(II) and trans-di-bromido-tetra-kis-[1-(2,6-diiso-propyl-phen-yl)-1H-imidazole-?N (3)]iron(II) diethyl ether disolvate.  

PubMed

The title compounds, [FeCl2(C15H20N2)4], (I), [FeBr2(C15H20N2)4], (II), and [FeBr2(C15H20N2)4]·2C4H10O, (IIb), respectively, all have triclinic symmetry, with (I) and (II) being isotypic. The Fe(II) atoms in each of the structures are located on an inversion center. They have octa-hedral FeX 2N4 (X = Cl and Br, respectively) coordination spheres with the Fe(II) atom coordinated by two halide ions in a trans arrangement and by the tertiary N atom of four aryl-imidazole ligands [1-(2,6-diiso-propyl-phen-yl)-1H-imidazole] in the equatorial plane. In the two independent ligands, the benzene and imidazole rings are almost normal to one another, with dihedral angles of 88.19?(15) and 79.26?(14)° in (I), 87.0?(3) and 79.2?(3)° in (II), and 84.71?(11) and 80.58?(13)° in (IIb). The imidazole rings of the two independent ligand mol-ecules are inclined to one another by 70.04?(15), 69.3?(3) and 61.55?(12)° in (I), (II) and (IIb), respectively, while the benzene rings are inclined to one another by 82.83?(13), 83.0?(2) and 88.16?(12)°, respectively. The various dihedral angles involving (IIb) differ slightly from those in (I) and (II), probably due to the close proximity of the diethyl ether solvent mol-ecule. There are a number of C-H?halide hydrogen bonds in each mol-ecule involving the CH groups of the imidazole units. In the structures of compounds (I) and (II), mol-ecules are linked via pairs of C-H?halogen hydrogen bonds, forming chains along the a axis that enclose R 2 (2)(12) ring motifs. The chains are linked by C-H?? inter-actions, forming sheets parallel to (001). In the structure of compound (IIb), mol-ecules are linked via pairs of C-H?halogen hydrogen bonds, forming chains along the b axis, and the diethyl ether solvent mol-ecules are attached to the chains via C-H?O hydrogen bonds. The chains are linked by C-H?? inter-actions, forming sheets parallel to (001). In (I) and (II), the methyl groups of an isopropyl group are disordered over two positions [occupancy ratio = 0.727?(13):0.273?(13) and 0.5:0.5, respectively]. In (IIb), one of the ethyl groups of the diethyl ether solvent mol-ecule is disordered over two positions (occupancy ratio = 0.5:0.5). PMID:25249858

Mafua, Roger; Jenny, Titus; Labat, Gael; Neels, Antonia; Stoeckli-Evans, Helen

2014-08-01

166

Esters of valerenic acid as potential prodrugs.  

PubMed

Valerenic acid (VA) is a ?2/3 subunit-specific modulator of ?-aminobutyric acid (GABA) type A (GABAA) receptors inducing anxiolysis. Here we analyze if VA-esters can serve as prodrugs and if different ester structures have different in vitro/in vivo effects. Modulation of GABAA receptors expressed in Xenopus oocytes was studied with 2-microelectrode-voltage-clamp. Anxiolytic effects of the VA-esters were studied on male C57BL/6N mice by means of the elevated plus maze-test; anticonvulsant properties were deduced from changes in seizure threshold upon pentylenetetrazole infusion. VA was detected in plasma confirming hydrolysis of the esters and release of VA in vivo. Esterification significantly reduced the positive allosteric modulation of GABAA (?1?3?2S) receptors in vitro. in vivo, the studied VA-ester derivatives induced similar or even stronger anxiolytic and anticonvulsant action than VA. While methylation and propylation of VA resulted in faster onset of anxiolysis, the action of VA-ethylester was longer lasting, but occurred with a significant delay. The later finding is in line with the longer lasting anticonvulsant effects of this compound. The estimated VA plasma concentrations provided first insight into the release kinetics from different VA-esters. This might be an important step for its future clinical application as a potential non-sedative anxiolytic and anticonvulsant. PMID:24680924

Hintersteiner, Juliane; Haider, Maximilian; Luger, Denise; Schwarzer, Christoph; Reznicek, Gottfried; Jäger, Walter; Khom, Sophia; Mihovilovic, Marko D; Hering, Steffen

2014-07-15

167

Esters of valerenic acid as potential prodrugs  

PubMed Central

Valerenic acid (VA) is a ?2/3 subunit-specific modulator of ?-aminobutyric acid (GABA) type A (GABAA) receptors inducing anxiolysis. Here we analyze if VA-esters can serve as prodrugs and if different ester structures have different in vitro/in vivo effects. Modulation of GABAA receptors expressed in Xenopus oocytes was studied with 2-microelectrode-voltage-clamp. Anxiolytic effects of the VA-esters were studied on male C57BL/6N mice by means of the elevated plus maze-test; anticonvulsant properties were deduced from changes in seizure threshold upon pentylenetetrazole infusion. VA was detected in plasma confirming hydrolysis of the esters and release of VA in vivo. Esterification significantly reduced the positive allosteric modulation of GABAA (?1?3?2S) receptors in vitro. in vivo, the studied VA-ester derivatives induced similar or even stronger anxiolytic and anticonvulsant action than VA. While methylation and propylation of VA resulted in faster onset of anxiolysis, the action of VA-ethylester was longer lasting, but occurred with a significant delay. The later finding is in line with the longer lasting anticonvulsant effects of this compound. The estimated VA plasma concentrations provided first insight into the release kinetics from different VA-esters. This might be an important step for its future clinical application as a potential non-sedative anxiolytic and anticonvulsant. PMID:24680924

Hintersteiner, Juliane; Haider, Maximilian; Luger, Denise; Schwarzer, Christoph; Reznicek, Gottfried; Jäger, Walter; Khom, Sophia; Mihovilovic, Marko D.; Hering, Steffen

2014-01-01

168

Folic Acid  

MedlinePLUS

Folic acid is used to treat or prevent folic acid deficiency. It is a B-complex vitamin needed by ... Folic acid comes in tablets. It usually is taken once a day. Follow the directions on your prescription label ...

169

Folic Acid  

MedlinePLUS

Folic acid is a B vitamin. It helps the body make healthy new cells. Everyone needs folic acid. For women who may get pregnant, it is really important. Getting enough folic acid before and during pregnancy can prevent major birth ...

170

Folic Acid  

MedlinePLUS

... acid Description Folic acid, or folate, is a B vitamin found in many beans, grains, fortified breakfast cereals, ... for use? Folic acid, or folate, is a B vitamin. It is promoted mainly as part of a ...

171

Characterization of a non-ribosomal peptide synthetase-associated diiron arylamine N-oxygenase from Pseudomonas syringae pv. phaseolicola  

Microsoft Academic Search

The regiospecific oxidation of aromatic amines to aryl nitro compounds is critical to the synthesis of several natural products having pharmacological importance. The arylamine N-oxygenase (AAO) from Streptomyces thioluteus (AurF) selectively oxidizes p-aminobenzoic acid to p-nitrobenzoic acid and has been the subject of investigation for its unique chemistry and substrate preferences. Little, however, is known about the biochemistry and substrate

Erin Platter; Michael Lawson; Christopher Marsh; Matthew H. Sazinsky

2011-01-01

172

Sulfonamides in the Environment as Veterinary Drugs  

Microsoft Academic Search

SAs, a structurally related group of antibiotics containing a similar 4-aminobenzene sulfonamide backbone, are used in agriculture,\\u000a aquaculture, animal husbandry, and also as human medicines. Competing with p-aminobenzoic acid in the enzymatic synthesis of dihydrofolic acid, SAs inhibit the growth and reproduction of bacteria. Once\\u000a released to the environment, SAs distribute themselves among different environmental compartments, along with their degradation

Premasis Sukul; Michael Spiteller

173

Crystal structure of 1,3-bis­(2,6-diiso­propyl­phen­yl)-4,5-dimethyl-1H-imid­azol-3-ium bromide di­chloro­methane disolvate  

PubMed Central

The title solvated salt, C29H41N2 +·Br?·2CH2Cl2 was obtained from the reaction of the Arduengo-type carbene 1,3-bis­(2,6-diiso­propyl­phen­yl)-1,3-dihydro-4,5-dimethyl-2H-imidazol-2-ylidene with Si2Br6 in di­chloro­methane. The complete cation is generated by a crystallographic mirror plane and the dihedral angle between the five-membered ring and the benzene ring is 89.8?(6)°; the dihedral angle between the benzene rings is 40.7?(2)°. The anion also lies on the mirror plane and both di­chloro­methane mol­ecules are disordered across the mirror plane over two equally occupied orientations. In the crystal, the cations are linked to the anions via C—H?Br hydrogen bonds. PMID:25484824

Berger, Matthias; Auner, Norbert; Bolte, Michael

2014-01-01

174

Crystal structure of 1,3-bis-(2,6-diiso-propyl-phen-yl)-4,5-dimethyl-1H-imid-azol-3-ium bromide di-chloro-methane disolvate.  

PubMed

The title solvated salt, C29H41N2 (+)·Br(-)·2CH2Cl2 was obtained from the reaction of the Arduengo-type carbene 1,3-bis-(2,6-diiso-propyl-phen-yl)-1,3-dihydro-4,5-dimethyl-2H-imidazol-2-ylidene with Si2Br6 in di-chloro-methane. The complete cation is generated by a crystallographic mirror plane and the dihedral angle between the five-membered ring and the benzene ring is 89.8?(6)°; the dihedral angle between the benzene rings is 40.7?(2)°. The anion also lies on the mirror plane and both di-chloro-methane mol-ecules are disordered across the mirror plane over two equally occupied orientations. In the crystal, the cations are linked to the anions via C-H?Br hydrogen bonds. PMID:25484824

Berger, Matthias; Auner, Norbert; Bolte, Michael

2014-11-01

175

Time-dependent effects of the flame retardant tris(1,3-dichloro-2-propyl) phosphate (TDCPP) on mRNA expression, in vitro and in ovo, reveal optimal sampling times for rapidly metabolized compounds.  

PubMed

The flame retardant, tris(1,3-dichloro-2-propyl) phosphate (TDCPP), was previously shown to affect chicken embryo growth, gallbladder size, and lipid homeostasis. A microarray study, however, revealed only modest transcriptional alterations in liver tissue of pipping embryos (days 20-21), which was attributed to the rapid metabolism of TDCPP throughout incubation. To identify the most appropriate sampling time for rapidly metabolized compounds, the present study assessed the time-dependent effects of TDCPP on 27 genes, in ovo (50 µg [116 nmol] TDCPP/g egg) and in vitro (10 µM), using a chicken ToxChip polymerase chain reaction array. The greatest magnitude in dysregulation (up to 362-fold) occurred on day 8 of incubation (in ovo) with alterations of genes involved in phase I, II, and III metabolism, among others. Gallbladder hypotrophy was observed by embryonic day 12, corroborating the finding in pipping embryos from our previous study. From days 12 to 19, genes involved in lipid homeostasis, steroid hormone metabolism, and oxidative stress were affected. In chicken embryonic hepatoctyes (CEHs), TDCPP was completely metabolized to bis(1,3-dichloro-2-propyl) phosphate (BDCPP) within 36 h, but transcriptional changes remained significant up to 36 h. These changes were not attributed to BDCPP exposure as it only altered 1 gene (CYP1A4). An 18-h exposure in CEHs altered the greatest number of genes, making it an appropriate time point for high-throughput chemical screening; however, depending on the biological pathways of interest, shorter or longer incubation times may be more informative. Overall, TDCPP elicits the transcriptional and phenotypic alterations observed in vitro and in ovo, whereas its major metabolite, BDCPP, is far less biologically active. PMID:25242413

Farhat, Amani; Crump, Doug; Porter, Emily; Chiu, Suzanne; Letcher, Robert J; Su, Guanyong; Kennedy, Sean W

2014-12-01

176

Acid Rain.  

ERIC Educational Resources Information Center

Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

Openshaw, Peter

1987-01-01

177

Acid rain  

Microsoft Academic Search

Acid precipitation includes not only rain but also acidified snow, hail and frost, as well as sulfur and nitrogen dust. The principal source of acid precipitation is pollution emitted by power plants and smelters. Sulfur and nitrogen compounds contained in the emissions combine with moisture to form droplets with a high acid content - sometimes as acidic as vinegar. When

1980-01-01

178

Study of disulfide reduction and alkyl chloroformate derivatization of plasma sulfur amino acids using gas chromatography-mass spectrometry.  

PubMed

Four disulfide-reducing agents, dithiothreitol (DTT), 2,3-dimercaptopropanesulfonate (DMPS), and the newly tested 2-mercaptoethanesulfonate (MESNA) and Tris(hydroxypropyl)phosphine (THP), were investigated in detail for release of sulfur amino acids in human plasma. After protein precipitation with trichloroacetic acid (TCA), the plasma supernatant was treated with methyl, ethyl, or propyl chloroformate via the well-proven derivatization-extraction technique and the products were subjected to gas chromatographic-mass spectrometric (GC-MS) analysis. All the tested agents proved to be rapid and effective reducing agents for the assay of plasma thiols. When compared with DTT, the novel reducing agents DMPS, MESNA, and THP provided much cleaner extracts and improved analytical performance. Quantification of homocysteine, cysteine, and methionine was performed using their deuterated analogues, whereas other analytes were quantified by means of 4-chlorophenylalanine. Precise and reliable assay of all examined analytes was achieved, irrespective of the chloroformate reagent used. Average relative standard deviations at each analyte level were ?6%, quantification limits were 0.1-0.2 ?mol L(-1), recoveries were 94-121%, and linearity was over three orders of magnitude (r(2) equal to 0.997-0.998). Validation performed with the THP agent and propyl chloroformate derivatization demonstrated the robustness and reliability of this simple sample-preparation methodology. PMID:22349320

Svagera, Zden?k; Hanzlíková, Dagmar; Simek, Petr; Hušek, Petr

2012-03-01

179

Aminocaproic Acid  

MedlinePLUS

Aminocaproic acid is used to control bleeding that occurs when blood clots are broken down too quickly. This type ... the baby is ready to be born). Aminocaproic acid is also used to control bleeding in the ...

180

Ethacrynic Acid  

MedlinePLUS

Ethacrynic acid, a 'water pill,' is used to treat swelling and fluid retention caused by various medical problems. It ... Ethacrynic acid comes as a tablet to take by mouth. It is usually taken once or twice a day ...

181

Mefenamic Acid  

MedlinePLUS

Mefenamic acid is used to relieve mild to moderate pain, including menstrual pain (pain that happens before or during a menstrual period). Mefenamic acid is in a class of medications called NSAIDs. ...

182

Peptide coupling between amino acids and the carboxylic acid of a functionalized chlorido-gold(I)-phosphane.  

PubMed

We have developed a protocol for the direct coupling between methyl ester protected amino acids and the chlorido-gold(I)-phosphane (p-HOOC(C6H4)PPh2)AuCl. By applying the EDC·HCl/NHS strategy (EDC·HCl = N-ethyl-N'-(3-(dimethylamino)propyl)carbodiimide hydrochloride, NHS = N-hydroxysuccinimide), the methyl esters of l-phenylalanine, glycine, l-leucine, l-alanine, and l-methionine are coupled with the carboxylic acid of the gold complex in moderate to good yields (62-88%). All amino acid tagged gold complexes were characterized by (1)H and (13)C NMR spectroscopy and high-resolution mass spectrometry. As corroborated by measurement of the angle of optical rotation, no racemization occurred during the reaction. The molecular structure of the leucine derivative was determined by single-crystal X-ray diffraction. In the course of developing an efficient coupling protocol, the acyl chlorides (p-Cl(O)C(C6H4)PPh2)AuX (X = Cl, Br) were also prepared and characterized. PMID:25203269

Kriechbaum, Margit; List, Manuela; Himmelsbach, Markus; Redhammer, Günther J; Monkowius, Uwe

2014-10-01

183

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.

184

Acid rain  

Microsoft Academic Search

The acid rain problem in the northeastern U.S. has been growing in severity and geographical areas affected. Acid rain has damaged, or will result in damage to visibility, physical structures and materials, aquatic life, timber, crops, and soils. The principal causes of acid rain in the northeastern U.S. are sulfur oxide and nitrogen oxide emissions from large power plants and

1980-01-01

185

Metabolism and excretion of 5-ethyl-2-{5-[4-(2-hydroxyethyl)piperazine-1-sulfonyl]-2-propoxyphenyl}-7-propyl-3,5-dihydropyrrolo[3,2-d]-pyrimidin-4-one (SK3530) in rats.  

PubMed

The in vitro and in vivo metabolism of a novel PDE 5 inhibitor, SK3530, was investigated in rats. Bile, plasma, feces, urine and liver samples were collected and analyzed using a high-performance liquid chromatography (HPLC) system equipped with ultraviolet (UV), mass spectrometric and radioactivity detectors. After a single oral administration, the mean radiocarbon recovery was 92.32+/-6.26%, with 91.25+/-6.25 and 1.07+/-0.21% in the feces and urine, respectively. The biliary excretion of radioactivity for the first 24 h period was approximately 38.82%, suggesting that SK3530 is cleared by hepatobiliary excretion. In vitro incubation of SK3530 with rat and human liver microsomes resulted in the formation of twelve and ten metabolites, respectively. SK3530 was extensively metabolized to twenty different metabolites, including three glucuronide and three sulfate conjugates in rats. The structures of these metabolites were elucidated based on MSn spectral analyses. Six major metabolic pathways were identified in the rat: N-dealkylation and oxidation of the hydroxyethyl moiety; N,N-deethylation and hydroxylation of the piperazine ring; hydroxylation of the propyl group and sulfate conjugation. An additional metabolite due to aromatic hydroxylation was also identified in hepatic microsomes. PMID:17318927

Lee, Jaeick; Yoo, Hye Hyun; Rhim, Kwang Jin; Sohn, Dong-Ryul; Kim, Dong-Hyun

2007-01-01

186

The Octadecyloxyethyl Ester of (S)-9-[3-Hydroxy-2-(Phosphonomethoxy) Propyl]Adenine Is a Potent and Selective Inhibitor of Hepatitis C Virus Replication in Genotype 1A, 1B, and 2A Replicons?  

PubMed Central

The octadecyloxyethyl (ODE) and hexadecyloxypropyl (HDP) esters of (S)-9-[3-hydroxy-2-(phosphonomethoxy)propyl]adenine (HPMPA) are potent inhibitors of orthopoxvirus, herpesvirus, human immunodeficiency virus type 1, and hepatitis B virus replication in vitro. HDP and ODE esters of (S)-HPMPA and (R)-HPMPA were evaluated for their activity in hepatitis C virus (HCV) replicon assays using luciferase (1B and 2A replicons) or RNA (1B) quantification. The ODE ester of (S)-HPMPA [ODE-(S)-HPMPA] was the most active compound, with 50% effective concentrations (EC50s) in the 0.69 to 1.31 ?M range. HDP and ODE esters of (R)-HPMPA were severalfold less active, while (S)-HPMPA and (R)-HPMPA were inactive. In genotype 1A and 1B replicons analyzed by HCV RNA analysis, ODE-(S)-HPMPA was the most active compound, with EC50s of 1.8 and 2.1 ?M, respectively. PMID:19289518

Wyles, David L.; Kaihara, Kelly A.; Korba, Brent E.; Schooley, Robert T.; Beadle, James R.; Hostetler, Karl Y.

2009-01-01

187

In vivo study of the effect of antiviral acyclic nucleotide phosphonate (R)-9-[2-(phosphonomethoxy)propyl]adenine (PMPA, tenofovir) and its prodrug tenofovir disoproxil fumarate on rat microsomal cytochrome P450.  

PubMed

The total content of rat liver microsomal cytochrome P450 (CYP) significantly decreased after repeated i.p. administration of the antiviral agent tenofovir ((R)-9-[2-(phosphonomethoxy)propyl] adenine) and tenofovir disoproxil at a daily dose 25 mg/kg, although the content of liver microsomal protein did not change. The decrease of the CYP content was accompanied by concomitant increase of the amount of inactive CYP form, cytochrome P420. This effect was confirmed by a parallel study of the activities of selected CYP forms, CYP2E1 (p-nitrophenol hydroxylation) and CYP1A2 (7-ethoxyresorufin deethylation). The activity (expressed relatively to the protein content) of both CYP forms decreased significantly following the decrease of the total CYP. On the other hand, the CYP2E1 activity expressed relatively to the decreasing total CYP content remained unchanged. However, CYP1A2 activity also decreased when calculated relatively to the total native CYP content indicating lower stability of this form. Semiquantitative RT-PCR showed no significant changes in expression of major rat liver microsomal CYP forms after tenofovir treatment. In conclusion, repeated administration of tenofovir in higher doses led to significant decrease of the relative proportion of active liver microsomal CYPs accompanied by a conversion of these enzymes to the inactive form (CYP420) maintaining the sum of CYP proteins unchanged. PMID:17949244

Anzenbacherová, E; Anzenbacher, P; Zídek, Z; Buchar, E; Kmonícková, E; Potmesil, P; Nekvindová, J; Veinlichová, A; Holý, A

2008-01-01

188

In vitro and in vivo assessment of the mutagenic activity of N-[N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-?-aspartyl]-L-phenylalanine 1-methyl ester, monohydrate (advantame).  

PubMed

Advantame (N-[N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-?-aspartyl]-L-phenylalanine 1-methyl ester, monohydrate), an N-substituted analogue of aspartame, has been developed as a high-intensity sweetener. It is approximately 100 and 20,000 times sweeter than aspartame and sucrose, respectively. In this study the safety of advantame has been evaluated using a series of in vitro and in vivo genotoxicity assays including, bacterial mutation, mammalian cell mutation, and mouse micronucleus tests. Advantame did not induce reverse mutations in Salmonella typhimurium and Escherichia coli at concentrations of up to 5000 ?g/plate. In the mammalian cell mutation assay, advantame did not induce mutation at the Hprt locus of L5178Y mouse lymphoma cells in two independent experiments, either in the absence or presence of S9. In vivo, there was no effect on the incidence of micronucleated immature or mature erythrocytes in bone marrow after oral administration of the test substance at any dose level (up to 2000 mg/kg body weight) or sampling time (24 and 48 h). The results of these studies demonstrate that advantame is without genotoxic potential. PMID:22036025

Otabe, A; Fujieda, T; Masuyama, T

2011-11-01

189

Structure-Activity Relationships for a Novel Series of Citalopram (1-(3-(dimethylamino)propyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile) Analogues at Monoamine Transporters  

PubMed Central

(±)-Citalopram (1, 1-(3-(dimethylamino)propyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile), and its eutomer, escitalopram (S(+)-1) are selective serotonin reuptake inhibitors (SSRIs) that are used clinically to treat anxiety and depression. To further explore structure-activity relationships at the serotonin transporter (SERT), a series of (±)-4- and 5-substituted citalopram analogues were designed, synthesized and evaluated for binding at the SERT, dopamine transporter (DAT) and norepinephrine transporter (NET) in native rodent tissue. Many of these analogues showed high SERT binding affinities (Ki = 1–40 nM) and selectivities over both NET and DAT. Selected enantiomeric pairs of analogues were synthesized and both retained enantioselectivity as with S- and R-1, wherein S > R at the SERT. In addition, the enantiomeric pairs of 1 and 5 were tested for binding at the homologous bacterial Leucine transporter (LeuT), wherein low affinities and the absence of enantioselectivity suggested distinctive binding sites for these compounds at SERT as compared to LeuT. These novel ligands will provide molecular tools to elucidate drug-protein interactions at the SERT and to relate those to behavioral actions, in vivo. PMID:20672825

Zhang, Peng; Cyriac, George; Kopajtic, Theresa; Zhao, Yongfang; Javitch, Jonathan A.; Katz, Jonathan L.; Newman, Amy Hauck

2010-01-01

190

Basically Acids  

NSDL National Science Digital Library

Students learn the basics of acid/base chemistry in a fun, interactive way by studying instances of acid/base chemistry found in popular films such as Harry Potter and the Prisoner of Azkaban and National Treasure. Students learn what acids, bases and indicators are and how they can be used, including invisible ink. They also learn how engineers use acids and bases every day to better our quality of life. Students' interest is piqued by the use of popular culture in the classroom.

University of Houston,

191

Gas-Phase Reactivity of Carboxylic Acid Functional Groups with Carbodiimides  

NASA Astrophysics Data System (ADS)

Gas-phase modification of carboxylic acid functionalities is performed via ion/ion reactions with carbodiimide reagents [ N-cyclohexyl- N'-(2-morpholinoethyl)carbodiimide (CMC) and [3-(3-Ethylcarbodiimide-1-yl)propyl]trimethylaminium (ECPT)]. Gas-phase ion/ion covalent chemistry requires the formation of a long-lived complex. In this instance, the complex is stabilized by an electrostatic interaction between the fixed charge quaternary ammonium group of the carbodiimide reagent cation and the analyte dianion. Subsequent activation results in characteristic loss of an isocyanate derivative from one side of the carbodiimide functionality, a signature for this covalent chemistry. The resulting amide bond is formed on the analyte at the site of the original carboxylic acid. Reactions involving analytes that do not contain available carboxylic acid groups (e.g., they have been converted to sodium salts) or reagents that do not have the carbodiimide functionality do not undergo a covalent reaction. This chemistry is demonstrated using PAMAM generation 0.5 dendrimer, ethylenediaminetetraacetic acid (EDTA), and the model peptide DGAILDGAILD. This work demonstrates the selective gas-phase covalent modification of carboxylic acid functionalities.

Prentice, Boone M.; Gilbert, Joshua D.; Stutzman, John R.; Forrest, William P.; McLuckey, Scott A.

2013-01-01

192

Acids (GCMP)  

NSDL National Science Digital Library

Acids: this is a resource in the collection "General Chemistry Multimedia Problems". We will observe the reaction of sodium bicarbonate with three acid solutions. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

193

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

194

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

195

Acid rain  

SciTech Connect

This book was written in a concise and readable style for the lay public. It's purpose was to make the public aware of the damage caused by acid rain and to mobilize public opinion to favor the elimination of the causes of acid rain.

Elsworth, S.

1985-01-01

196

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

197

Acid rain  

SciTech Connect

The acid rain problem in the northeastern U.S. has been growing in severity and geographical areas affected. Acid rain has damaged, or will result in damage to visibility, physical structures and materials, aquatic life, timber, crops, and soils. The principal causes of acid rain in the northeastern U.S. are sulfur oxide and nitrogen oxide emissions from large power plants and smelters in the Ohio River Valley. Immediate corrective action and appropriate research are needed to reduce acid precipitation. Short-term programs that will define the rate of environmental deterioration, remaining environmental capacity to resist sudden deterioration, mechanisms of acid rain formation, and costs of various control options must be developed. (3 maps, 13 references, 1 table)

Bess, F.D.

1980-01-01

198

Synthesis, characterization and anti proliferative effect of [Au(en) 2]Cl 3 and [Au(N- propyl-en) 2]Cl 3 on human cancer cell lines  

NASA Astrophysics Data System (ADS)

Two Au(III) complexes of the type [Au(en) 2]Cl 3 ( 2a) and [Au(N-pr-en) 2]Cl 3 ( 3a) were synthesized by reacting Auric acid (HAuCl 4·3H 2O) with 2 equiv. ethylenediamine (en) or N-alkyl substituted ethylenediamine ligands. This metallodrug was characterized by various analytical and spectroscopic techniques such as elemental analysis, UV-Vis, Far-IR, 1H NMR and solution 13C as well as solid 13C and 15N NMR. Potentiality of [Au(en) 2]Cl 3 and [Au(N-pr-en) 2]Cl 3 as an anti-cancer agent were investigated by measuring some relevant physicochemical and biochemical properties such as stability of Au-N bonds by vibrational stretching from Far IR as well as cytotoxicity and stomach cancer cell inhibiting effect, respectively. The solid-state 15N NMR chemical shift shows that the ligand is strongly bound to gold(III) centre via N atoms. The computational study of 2a shows that the gold coordination sphere adopts distorted square planar geometry with bidentate ethylenediamine ligands acting as a tetradentate chelate. While stable in the solution state, the in vitro biological studies performed with these compounds 2a in solution showed higher activity towards the inhibitory effects of the human cancer cell lines such as prostate cancer (PC-3) and gastric carcinoma (SGC-7901) than that of the N-substituted gold(III) complex ( 3a). Cytotoxicity of the new compounds has also been estimated in PC-3 and SGC-7901 cells.

Isab, Anvarhusein A.; Shaikh, M. Nasiruzzaman; Monim-ul-Mehboob, M.; Al-Maythalony, Bassem A.; Wazeer, Mohammed I. M.; Altuwaijri, Saleh

2011-09-01

199

A targeted metabolomic protocol for short-chain fatty acids and branched-chain amino acids.  

PubMed

Research in obesity and metabolic disorders that involve intestinal microbiota demands reliable methods for the precise measurement of the short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) concentration. Here, we report a rapid method of simultaneously determining SCFAs and BCAAs in biological samples using propyl chloroformate (PCF) derivatization followed by gas chromatography mass spectrometry (GC-MS) analysis. A one-step derivatization using 100 µL of PCF in a reaction system of water, propanol, and pyridine (v/v/v = 8:3:2) at pH 8 provided the optimal derivatization efficiency. The best extraction efficiency of the derivatized products was achieved by a two-step extraction with hexane. The method exhibited good derivatization efficiency and recovery for a wide range of concentrations with a low limit of detection for each compound. The relative standard deviations (RSDs) of all targeted compounds showed good intra- and inter-day (within 7 days) precision (< 10%), and good stability (< 20%) within 4 days at room temperature (23-25 °C), or 7 days when stored at -20 °C. We applied our method to measure SCFA and BCAA levels in fecal samples from rats administrated with different diet. Both univariate and multivariate statistics analysis of the concentrations of these target metabolites could differentiate three groups with ethanol intervention and different oils in diet. This method was also successfully employed to determine SCFA and BCAA in the feces, plasma and urine from normal humans, providing important baseline information of the concentrations of these metabolites. This novel metabolic profile study has great potential for translational research. PMID:23997757

Zheng, Xiaojiao; Qiu, Yunping; Zhong, Wei; Baxter, Sarah; Su, Mingming; Li, Qiong; Xie, Guoxiang; Ore, Brandon M; Qiao, Shanlei; Spencer, Melanie D; Zeisel, Steven H; Zhou, Zhanxiang; Zhao, Aihua; Jia, Wei

2013-08-01

200

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

201

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...

202

Tranexamic Acid  

MedlinePLUS

... used to treat heavy bleeding during the menstrual cycle (monthly periods) in women. Tranexamic acid is in ... as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this ...

203

Acidic precipitation  

SciTech Connect

The authors present an overview of the environmental chemistry and transport phenomena of air pollutants, biological and ecological effects of acidic precipitation, mitigation of acidified aquatic ecosystems, and modelling approaches. This book reviews what is known about the impact of acidic deposition in the biota and processes in complex ecosystems such as lakes, streams, and forests. The specific effects on crops, trees, fish, and microorganisms are also discussed.

Adriano, D.C. (Georgia Univ., Aiken, SC (USA)); Johnson, A.H. (Pennsylvania Univ., Philadelphia, PA (USA))

1989-01-01

204

Furan formation from fatty acids as a result of storage, gamma irradiation, UV-C and heat treatments.  

PubMed

The effects of gamma and UV-C irradiation in comparison with thermal processing and storage at 25°C on formation of furan from different fatty acids were investigated. Results showed that furan was generated from polyunsaturated fatty acids such as linoleic and linolenic acid during thermal (120°C, 25min) and UV-C (11.5J/cm(2)) treatments. Gamma irradiation (up to 20kGy) did not induce formation of significant amounts of furan from any of the fatty acids studied. Storage of unsaturated fatty acid emulsions at 25°C for 3days led to the formation of furan (7-11ng/mL) even without prior thermal or non-thermal treatments. pH significantly impacted furan formation with >3.5times more furan formed at pH 9 than at pHs 3 or 6 during 3days at 25°C. The addition of Trolox, BHA, and propyl gallate had no significant effect on furan formation from linolenic acid while ?-tocopherol and FeSO4 promoted furan formation. PMID:25577103

Fan, Xuetong

2015-05-15

205

Electrospray ionization mass spectral studies of N,N-dialkylaminoethane-2-sulphonic acids.  

PubMed

Oxidative reactions of VX type compounds and N,N-dialkylaminoethane-2-thiols that are precursors for VX compounds produce N,N-dialkylaminoethane-2-sulphonic acids, N(R(1))(R(2))-CH(2)-CH(2)SO(3)H (where R(1) and R(2) = methyl, ethyl, n-propyl and isopropyl, 1-10), as the degradation products, and these degradation products are considered as markers for the detection of chemicals listed in the schedules of Chemical Weapons Convention (CWC) chemicals. Off-site detection of such degradation products in aqueous samples is an important task in the verification of CWC-related chemicals. Here we report a simple method involving the direct analysis of aqueous samples using positive and/or negative ion electrospray ionization (ESI) for the screening, detection and identification of N,N-dialkylaminoethane-2-sulphonic acids, avoiding sample preparation and chromatographic steps. The positive ion ESI mass spectra of all the compounds result in abundant [M+Na](+) ions, and the negative ion spectra show abundant [M-H](-) ions to confirm their molecular weight. The collision-induced dissociation spectra of [M+Na](+) and [M-H](-) give characteristic product ions by which it is easy to detect and identify all the studied N,N-dialkylaminoethane-2-sulphonic acids including those of isomeric compounds. The method is successfully applied to detect the spiked chemical, N,N-diisopropylaminoethane-2-sulphonic acid, present in a water sample received in a proficiency test. PMID:17979103

Lakshmi, V V S; Prabhakar, S; Murty, M R V S; Vairamani, M

2007-01-01

206

Ampholine-functionalized hybrid organic-inorganic silica material as sorbent for solid-phase extraction of acidic and basic compounds.  

PubMed

A novel sorbent for solid-phase extraction (SPE) was synthesized by chemical immobilization of ampholine on hybrid organic-inorganic silica material. The ampholine-functionalized hybrid organic-inorganic silica sorbent is consisted of aliphatic amine groups, carboxyl groups and long carbon chains, allowing for extraction of both acidic and basic compounds. The retention properties of the developed sorbent were evaluated for 1-hydroxy-2-naphthoic acid (HNA), 1-naphthoic acid (NA), 3-hydroxybenzoic acid (HBA), benzoic acid (BA), sorbic acid (SA), vanillic aldehyde (VA), butyl 4-hydroxybenzoate (BHB), propyl 4-hydroxybenzoate (PHB), ethyl 4-hydroxybenzoate (EHB), and methyl 4-hydroxybenzoate (MHB). The results show that such a sorbent has three types of interaction, i.e., electrostatic interaction, hydrophobic interaction, and hydrogen bonding, exhibiting high extraction efficiency towards the compounds tested. The adsorption capacities of the analytes ranged from 0.61 to 6.54?gmg(-1). The reproducibility of the sorbent preparation was evaluated at three spiking concentration levels, with relative standard deviations (RSDs) of 1.0-10.5%. The recoveries of ten acidic and basic compounds spiked in beverage Coca-Cola(®) sample ranged from 82.5% to 98.2% with RSDs less than 5.8%. Under optimum conditions, the ampholine-functionalized hybrid organic-inorganic silica sorbent rendered higher extraction efficiency for acidic compounds than that of the commercially available ampholine-functionalized silica particles, and was comparable to that of the commercial Oasis WAX and Oasis WCX. PMID:23953713

Wang, Tingting; Chen, Yihui; Ma, Junfeng; Chen, Mingliang; Nie, Chenggang; Hu, Minjie; Li, Ying; Jia, Zhijian; Fang, Jianghua; Gao, Haoqi

2013-09-20

207

Stereospecific ligands and their complexes. Part XII. Synthesis, characterization and in vitro antiproliferative activity of platinum(IV) complexes with some O,O?-dialkyl esters of (S,S)-ethylenediamine-N,N?-di-2-propanoic acid against colon cancer (HCT-116) and breast cancer (MDA-MB-231) cell lines  

NASA Astrophysics Data System (ADS)

Synthesis of three new platinum(IV) complexes C1-C3, with bidentate N,N?-ligand precursors, O,O?-dialkyl esters (alkyl = propyl, butyl and pentyl), of (S,S)-ethylenediamine-N,N?-di-2-propanoic acid, H2-S,S-eddp were reported. The reported platinum(IV) complexes characterized by elemental analysis and their structures were discussed on the bases of their infrared, 1H and 13C NMR spectroscopy. In vitro antiproliferative activity was determined on tumor cell lines: human colon carcinoma HCT-116 and human breast carcinoma MDA-MB-231, using MTT test.

Stojkovi?, Danijela Lj.; Jevti?, Verica V.; Radi?, Gordana P.; ?a?i?, Dragana S.; ?ur?i?, Milena G.; Markovi?, Snežana D.; Ðinovi?, Vesna M.; Petrovi?, Vladimir P.; Trifunovi?, Sre?ko R.

2014-03-01

208

Gas chromatographic-mass spectrometric determination of alkylphosphonic acids from aqueous samples by ion-pair solid-phase extraction on activated charcoal and methylation.  

PubMed

In the present paper, we report an improved ion-pair solid-phase extraction (IP-SPE) method for the analysis of alkylphosphonic acids, namely, methyl, ethyl and propylphosphonic acids, present in the aqueous sample. The aqueous sample was mixed with an ion-pair reagent, phenyltrimethylammonium hydroxide (PTMAH) and passed through activated charcoal SPE cartridge. The retained chemicals in the cartridge were extracted with methanol and analysed by gas chromatography-mass spectrometry (GC-MS) under the electron impact ionization (EI) mode. The analytes were converted to their methyl esters by pyrolytic methylation in the hot GC injection port. The recoveries of alkylphosphonic acids were above 95% and the minimum detection limits were as low as 10 ng/mL. The recovery of the test chemicals was tested with solvents, dichloromethane, n-hexane, ethyl acetate, acetone, acetonitrile and methanol. The chemicals could be efficiently extracted by the hydrophilic solvents. The method did not work at the highly acidic pH (when acidified with dilute HCl) but worked well from pH 4.0 to 14.0. The present method was also tested with other tetra-(methyl, ethyl, propyl and n-butyl)ammonium hydroxides. The test chemicals were not converted to their methyl and ethyl esters with tetramethyl and tetraethylammonium hydroxides, whereas they were converted to their corresponding propyl and n-butyl esters with tetrapropyl and tetra(n-butyl)ammonium hydroxides. The method was also applied to two highly cross-linked polymeric sorbents DSC-6S and Oasis HLB. The recovery of the chemicals on these sorbents was observed to be poor. Methylation using phenyltrimethylammonium hydroxide is non-hazardous and advantageous over methylation using diazomethane. The method was applied to the analysis of aqueous samples given in one of the official proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons and all the spiked chemicals were identified as methyl esters. PMID:17507025

Vijaya Saradhi, U V R; Prabhakar, S; Jagadeshwar Reddy, T; Murty, M R V S

2007-07-20

209

Thermodynamic and quantum chemistry characterization of the adsorption of triazole derivatives during Muntz corrosion in acidic and neutral solutions  

NASA Astrophysics Data System (ADS)

Some triazole derivatives (4-amino-5-mercapto-3-methyl 1,2,4-triazole (AMMT), 4-amino-5-mercapto-3-ethyl 1,2,4-triazole (AMET) and 4-amino-5-mercapto-3-propyl 1,2,4-triazole (AMPT)) have been evaluated as new corrosion inhibitors for the corrosion of muntz alloy (60Cu-40Zn) in acidic and neutral solutions. The adsorption of these compounds has been tested thermodynamically which was found to be of a physisorption mode. Furthermore, some activation thermodynamic parameters such as ? H*, ? S* and ? G* of activation have been estimated. In addition, a trial to find a quantitative relationship between the inhibition efficiency and the electronic properties of the inhibitor molecules was carried out.

Allam, Nageh K.

2007-03-01

210

Luminescent lanthanide (Eu3+, Tb3+) hybrids with 4-vinylbenzeneboronic acid functionalized Si-O bridges and beta-diketones.  

PubMed

4-Vinylphenylboronic acid ligand (VPBA) is functionalized with two crosslinking reagents (3-(triethoxysilyl)-propylisocyanate [TEPIC] and 3-(trimethoxysilyl) propyl methacrylate [TMPMA]) to achieve the two special molecular bridge VPBA-TEPIC and VPBA-TMPMA. Meanwhile, beta-diketone ligands (2-thenoyltrifluoroacetone [TTA], acetyl acetone [ACAC]) as the second ligands play the role of the main energy donor, which absorb abundant energy in ultraviolet-visible extent and then transfer the energy to the corresponding lanthanide ions (Eu(3+), Tb(3+)) to sensitize their emission of them. Eight binary and ternary Eu(3+), Tb(3+) hybrids with VPBA-TEPIC (VPBA-TMPMA) and TTA (ACAC) have been constructed, whose photoluminescence properties are studied in depth and suggest that the ternary hybrids show the favorable characteristic luminescent properties (longer lifetime and higher quantum efficiency). PMID:21466557

Yan, Bing; Guo, Min; Qiao, Xiao-Fei

2011-01-01

211

Uric acid - urine  

MedlinePLUS

The urine uric acid test measures the level of uric acid in urine. Uric acid level can also be checked using a blood ... to choose the best medicine to lower uric acid level in the blood. Uric acid is a ...

212

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

213

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

214

Amino Acids  

NSDL National Science Digital Library

The Featured Molecules this month are the 20 standard ?-amino acids found in proteins and serve as background to the paper by Barone and Schmidt on the Nonfood Applications of Proteinaceous Renewable Materials. The molecules are presented in two formats, the neutral form and the ionized form found in solution at physiologic pH.

215

Acid Rain  

NSDL National Science Digital Library

This activity is part of Planet Diary and is an online examination into acid rain and sulfur dioxide emissions. Students research which states have succeeded in reducing sulfur dioxide emissions between 1980 and 1999, and which states emissions have increased. This activity is accompanied by a page of websites for further information.

216

Acid Attack  

NSDL National Science Digital Library

In this activity, students explore the effect of chemical erosion on statues and monuments. They use chalk to see what happens when limestone is placed in liquids with different pH values. They also learn several things that engineers are doing to reduce the effects of acid rain.

Integrated Teaching And Learning Program

217

SO?H-functionalized acidic ionic liquids as catalysts for the hydrolysis of cellulose.  

PubMed

The conversion of cellulose into valuable chemicals to deal with the depletion of fossil fuel has got much attention. Completing the hydrolysis of cellulose under mild conditions is the key step. In this study, six kinds of SO(3)H-functionalized acidic ionic liquids were used as acid catalyst to promote the hydrolysis of cellulose in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). All of them were efficient for the hydrolysis of cellulose, with the maximum total reducing sugars (TRS) yields over 83% at 100 °C. Acidic ionic liquids with analogous structures showed similar catalytic activities. Triethyl-(3-sulfo-propyl)-ammonium hydrogen sulfate (IL-5 in this study) was the optimum ionic liquid for cellulose hydrolysis, with the maximum TRS yield at 100 °C up to 99% when the dosage used was 0.2g. In addition, the water in [BMIM]Cl had negative effect on cellulose hydrolysis. Therefore, controlling the content of water in a comparatively low level is quite necessary. PMID:23218286

Liu, Yuanyuan; Xiao, Wenwen; Xia, Shuqian; Ma, Peisheng

2013-01-30

218

Pharmacology of oleanolic acid and ursolic acid  

Microsoft Academic Search

Oleanolic acid and ursolic acid are triterpenoid compounds that exist widely in food, medicinal herbs and other plants. This review summarizes the pharmacological studies on these two triterpenoids. Both oleanolic acid and ursolic acid are effective in protecting against chemically induced liver injury in laboratory animals. Oleanolic acid has been marketed in China as an oral drug for human liver

Jie Liu

1995-01-01

219

HYDROFLUORIC ACID Safety Office  

E-print Network

acids like Sulfuric and Hydrochloric. Hydrofluoric Acid is an acid like no other. It is so potentHYDROFLUORIC ACID SAFETY Safety Office University ofTennessee Space Institute Tullahoma, TN #12;What is Hydrofluoric Acid ? Hydrofluoric acid is a "weak" inorganic acid. Primarily used

Davis, Lloyd M.

220

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

221

Nicotinuric Acid  

PubMed Central

OBJECTIVE Metabolic syndrome is a multiplex disorder and puts patients on the road to type 2 diabetes and atherosclerotic cardiovascular diseases. However, a surrogate biomarker in plasma or urine in fully reflecting features of metabolic syndrome has not been explored. RESEARCH DESIGN AND METHODS Urine metabolomics has potential utility in metabolic profiling because urine metabolites analysis reflects global outflux of metabolic change. Accordingly, we collected data on subjects (n = 99) with overweight, dyslipidemia, hypertension or impaired glucose tolerance and took a metabolomics approach to analyze the metabolites of urine revealed in metabolic syndrome by high-performance liquid chromatography–time-of-flight mass spectrometry and elicit potential biomarkers to picture metabolic syndrome. RESULTS Our results revealed that the urine nicotinuric acid value of subjects with diabetes (HbA1c ?6.5% or those receiving diabetes medications) (n = 25) was higher than subjects without diabetes (n = 37) (221 ± 31 vs. 152 ± 13 × 103 mAU, P = 0.0268). Moreover, urinary nicotinuric acid level was positively correlated with body mass index, blood pressure, total cholesterol, low-density lipoprotein cholesterol, triacylglycerol and high sensitivity C-reactive protein, but negatively correlated with high-density lipoprotein cholesterol. CONCLUSIONS This is the first study, to our knowledge, to propose that nicotinuric acid represents an important pathogenic mechanism in process from metabolic syndrome to diabetes and atherosclerotic cardiovascular disease. PMID:23275373

Huang, Chun-Feng; Cheng, Mei-Ling; Fan, Chun-Ming; Hong, Chuang-Ye; Shiao, Ming-Shi

2013-01-01

222

Bactericidal photoproducts in medium containing riboflavin plus aromatic compounds and MnCl2.  

PubMed

Exposure to visible light of growth medium containing riboflavin and indole at low concentrations created photoproducts highly toxic to Salmonella typhimurium and other bacteria. No toxicity was detected in the dark or when either of these two components was present singly. Other aromatic compounds (serotonin, indole-3-acetic acid, indole-3-propionic acid, tryptophan, tyrosine, phenylalanine, and p-aminobenzoic acid) tested in place of indole produced various degrees of toxicity. The presence of MnCl2 significantly enhanced the toxicity. Addition of catalase eliminated the toxicity, indicating an important role for hydrogen peroxide. PMID:6349761

Chelala, C A; Margolin, P

1983-06-01

223

Chemical and Enzymatic Stability of Amino acid Prodrugs Containing Methoxy, Ethoxy and Propylene Glycol Linkers  

PubMed Central

Purpose To evaluate the chemical and enzymatic stabilities of methoxy, ethoxy and propylene glycol linker containing prodrugs in order to find a suitable linker for prodrugs of carboxylic acids with amino acids. Methods L-valine and L-phenylalanine prodrugs of model compounds (benzoic acid and phenyl acetic acid) containing methoxy, ethoxy and propylene glycol linkers were synthesized. The hydrolysis rate profile of each compound was studied at physiologically relevant pHs (1.2, 4, 6 and 7.4). Enzymatic hydrolysis of propylene glycol containing compounds was studied using Caco-2 homogenate as well as purified enzymes, valacyclovirase. Results It was observed that the stability of the prodrugs increases with the linker length (propyl>ethyl>methyl). The model prodrugs were stable at acidic pH as compared to basic pH. It was observed that the prodrug with the aliphatic amino acid promoiety was more stable as compared to its aromatic counterpart. The comparison between benzyl and the phenyl model compounds revealed that the amino acid side chain is significant in determining the stability of the prodrug whereas the benzyl or phenyl carboxylic acid had little or no effect on the stability. The enzymatic activation studies of propylene glycol linker prodrug in presence of valacyclovirase and cell homogenate showed faster generation of the parent drug at pH 7.4. The half life of prodrugs at pH 7.4 was more than 12 hours, whereas in presence of cell homogenate the half lives were less than 1 hour. Hydrolysis by Caco-2 homogenate generated the parent compound in two steps, where the prodrug was first converted to the intermediate, propylene glycol benzoate, which was then converted to the parent compound (benzoic acid). Enzymatic hydrolysis of propylene glycol containing prodrugs by valacyclovirase showed hydrolysis of the amino acid ester part to generate the propylene glycol ester of model compound (propylene glycol benzoate) as the major product. Conclusion The methoxy linker containing amino acid prodrugs were the least stable while propylene glycol linker containing prodrugs were most stable. This work suggests that the propylene glycol linker is an optimal linker for amino acids prodrugs since it has good chemical stability and is enzymatically hydrolyzed to yield the parent drug. This approach can be further extended to other non-amino acid prodrugs and to provide a chemical handle to modify lead molecules containing carboxylic group(s). PMID:19566080

Gupta, Deepak; Gupta, Sheeba Varghese; Lee, Kyung-Dall; Amidon, Gordon L.

2012-01-01

224

Folic acid - test  

MedlinePLUS

Folic acid is a type of B vitamin. This article discusses the test to measure the amount of folic acid in the blood. ... that may interfere with test results, including folic acid supplements. Drugs that can decrease folic acid measurements ...

225

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 ...

226

Mimicking the hierarchical functions of dentin collagen cross-links with plant derived phenols and phenolic acids.  

PubMed

Proanthocyanidins (PACs) are secondary plant metabolites that mediate nonenzymatic collagen cross-linking and enhance the properties of collagen based tissue, such as dentin. The extent and nature of cross-linking is influenced by the composition and specific chemical structure of the bioactive compounds present in certain PAC-rich extracts. This study investigated the effect of the molecular weight and stereochemistry of polyphenol compounds on two important properties of dentin, biomechanics, and biostability. For that, purified phenols, a phenolic acid, and some of its derivatives were selected: PAC dimers (A1, A2, B1, and B2) and a trimer (C1), gallic acid (Ga), its esters methyl-gallate (MGa) and propyl-gallate (PGa), and a pentagalloyl ester of glucose (PGG). Synergism was assessed by combining the most active PAC and gallic acid derivative. Mechanical properties of dentin organic matrix were determined by the modulus of elasticity obtained in a flexural test. Biostability was evaluated by the resistance to collagenase degradation. PACs significantly enhanced dentin mechanical properties and decreased collagen digestion. Among the gallic acid derivatives, only PGG had a significant enhancing effect. The lack of observed C1:PGG synergy indicates that both compounds have similar mechanisms of interaction with the dentin matrix. These findings reveal that the molecular weight of polyphenols have a determinant effect on their interaction with type I collagen and modulates the mechanism of cross-linking at the molecular, intermolecular, and inter-microfibrillar levels. PMID:25379878

Vidal, Cristina M P; Leme, Ariene A; Aguiar, Thaiane R; Phansalkar, Rasika; Nam, Joo-Won; Bisson, Jonathan; McAlpine, James B; Chen, Shao-Nong; Pauli, Guido F; Bedran-Russo, Ana

2014-12-16

227

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.

228

New bioactive fatty acids  

Technology Transfer Automated Retrieval System (TEKTRAN)

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)-octad...

229

New Bioactive Fatty Acids  

Technology Transfer Automated Retrieval System (TEKTRAN)

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 new compounds, 7,10-dihydroxy-8(E)-octadecen...

230

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

231

Solvent effects on the formation of nanoparticles and multilayered coatings based on hydrogen-bonded interpolymer complexes of poly(acrylic acid) with homo- and copolymers of N-vinyl pyrrolidone.  

PubMed

The formation of hydrogen-bonded interpolymer complexes between poly(acrylic acid) and poly(N-vinyl pyrrolidone) as well as amphiphilic copolymers of N-vinyl pyrrolidone with vinyl propyl ether has been studied in aqueous and organic solutions. It was demonstrated that introduction of vinyl propyl ether units into the macromolecules of the nonionic polymer enhances their ability to form complexes in aqueous solutions due to more significant contribution of hydrophobic effects. The complexation was found to be a multistage process that involves the formation of primary polycomplex particles, which further aggregate to form spherical nanoparticles. Depending on the environmental factors (pH, solvent nature), these nanoparticles may either form stable colloidal solutions or undergo further aggregation, resulting in precipitation of interpolymer complexes. In organic solvents, the intensity of complex formation increases in the following order: methanol < ethanol < isopropanol < dioxane. The multilayered coatings were developed using layer-by-layer deposition of interpolymer complexes on glass surfaces. It was demonstrated that the solvent nature affects the efficiency of coating deposition. PMID:18980359

Zhunuspayev, Daulet E; Mun, Grigoriy A; Hole, Patrick; Khutoryanskiy, Vitaliy V

2008-12-01

232

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.

233

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

234

The furan fatty acid metabolite CMPF is elevated in diabetes and induces ? cell dysfunction.  

PubMed

Gestational diabetes (GDM) results from failure of the ? cells to adapt to increased metabolic demands; however, the cause of GDM and the extremely high rate of progression to type 2 diabetes (T2D) remains unknown. Using metabolomics, we show that the furan fatty acid metabolite 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) is elevated in the plasma of humans with GDM, as well as impaired glucose-tolerant and T2D patients. In mice, diabetic levels of plasma CMPF induced glucose intolerance, impaired glucose-stimulated insulin secretion, and decreased glucose utilization. Mechanistically, we show that CMPF acts directly on the ? cell, causing impaired mitochondrial function, decreasing glucose-induced ATP accumulation, and inducing oxidative stress, resulting in dysregulation of key transcription factors and ultimately reduced insulin biosynthesis. Importantly, specifically blocking its transport through OAT3 or antioxidant treatment could prevent CMPF-induced ? cell dysfunction. Thus, CMPF provides a link between ? cell dysfunction and GDM/T2D that could be targeted therapeutically. PMID:24703697

Prentice, Kacey J; Luu, Lemieux; Allister, Emma M; Liu, Ying; Jun, Lucy S; Sloop, Kyle W; Hardy, Alexandre B; Wei, Li; Jia, Weiping; Fantus, I George; Sweet, Douglas H; Sweeney, Gary; Retnakaran, Ravi; Dai, Feihan F; Wheeler, Michael B

2014-04-01

235

Synthesis and biological evaluation of quinic acid derivatives as anti-inflammatory agents.  

PubMed

Quinic acid (QA) esters found in hot water extracts of Uncaria tomentosa (a.k.a. cat's claw) exert anti-inflammatory activity through mechanisms involving inhibition of the pro-inflammatory transcription factor nuclear factor kappa B (NF-kappaB). Herein, we describe the synthesis and biological testing of novel QA derivatives. Inhibition of NF-kappaB was assessed using A549 (Type II alveolar epithelial-like) cells that stably express a secreted alkaline phosphatase (SEAP) reporter driven by an NF-kappaB response element. A549-NF-kappaB cells were stimulated with TNF-alpha (10 ng/mL) in the presence or absence of QA derivative for 18 hours followed by measurement of SEAP activity. Amide substitution at the carboxylic acid position yielded potent inhibitors of NF-kappaB. A variety of modifications to the amide substitution were tolerated with the N-propyl amide derivative being the most potent. Further examination of the SAR demonstrated that acetylation of the hydroxyl groups reduced NF-kappaB inhibitory activity. QA amide derivatives lacked anti-oxidant activity and were found to be neither anti-proliferative nor cytotoxic at concentrations up to 100 microM. In conclusion, we have discovered a novel series of non-toxic QA amides that potently inhibit NF-kappaB, despite their lack of anti-oxidant activity. Mechanistic studies and pre-clinical efficacy studies in various inflammatory animal models are on-going. PMID:19674895

Zeng, Kui; Thompson, Karin Emmons; Yates, Charles R; Miller, Duane D

2009-09-15

236

A sensitive and selective chemosensor for ascorbic acid based on a fluorescent nitroxide switch.  

PubMed

Ascorbic acid (AsA), also known as vitamin C, is a vital small-molecule antioxidant with multiple functions in vivo. It's the major natural antioxidant found in plants and is also an essential component of human nutrition. AsA plays a key role in many diseases-related biological metabolism. Therefore, sensitive and selective detection of AsA is greatly important in pharmaceutical, clinical and food industry. Here a sensitive and selective sensor for ascorbic acid detection based on the recovered fluorescence of NAPS-NO (N-propyl-triethoxysilane-4-(4-ylamino-1-oxy-2,2,6,6-tetramethylpiperdine)- naphthalimide) probe is described. The fluorescence of the naphthalimide moiety of NAPS-NO is inhibited by the nitroxide group, which is covalently linked to the fluorophore. Then, ascorbic acid reacts rapidly with the nitroxide moiety of NAPS-NO to form hydroxylamine, and the fluorescence properties of the naphthalimide moiety are recovered and the ESR signal decayed. Over a wide range from 80nM to 50?M, a good linear relationship between the fluorescence intensity and the concentration of ascorbic acid was found and the detection limit was estimated to be as low as 20nM. To confirm the practical usefulness of the fluorophore-nitroxide probe, we demonstrated the use of NAPS-NO for the measurement of AsA in human blood serum and also successfully determined the concentration of AsA in HEK 293 cell lysate. Results from confocal laser scanning microscopy experiments demonstrated that this chemosensor is cell permeable and can be used as a fluorescent probe for monitoring ascorbic acid in living cells. PMID:25476297

Yang, Tian; Zheng, Baozhan; Liang, Hengxing; Wan, Yuping; Du, Juan; Xiao, Dan

2015-01-15

237

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

238

The Role of Hydroxyl Group Acidity on the Activity of Silica-Supported Secondary Amines for the Self-Condensation of n-Butanal.  

PubMed

The catalytic activity of secondary amines supported on mesoporous silica for the self-condensation of n-butanal to 2-ethylhexenal can be altered significantly by controlling the Brønsted acidity of M?OH species present on the surface of the support. In this study, M?OH (M=Sn, Zr, Ti, and Al) groups were doped onto the surface of SBA-15, a mesoporous silica, prior to grafting secondary propyl amine groups on to the support surface. The catalytic activity was found to depend critically on the synthesis procedure, the nature and amount of metal species introduced and the spatial separation between the acidic sites and amine groups. DFT analysis of the reaction pathway indicates that, for weak Brønsted acid groups, such as Si?OH, the rate-limiting step is C?C bond formation, whereas for stronger Brønsted acid groups, such as Ti and Al, hydrolysis of iminium species produced upon C?C bond formation is the rate-limiting step. Theoretical analysis shows further that the apparent activation energy decreases with increasing Brønsted acidity of the M?OH groups, consistent with experimental observation. PMID:25314616

Shylesh, Sankaranarayanapillai; Hanna, David; Gomes, Joseph; Canlas, Christian G; Head-Gordon, Martin; Bell, Alexis T

2015-02-01

239

Inhibitory effect of gallic acid and its esters on 2,2'-azobis(2-amidinopropane)hydrochloride (AAPH)-induced hemolysis and depletion of intracellular glutathione in erythrocytes.  

PubMed

The protective effect of gallic acid and its esters, methyl, propyl, and lauryl gallate, against 2,2'-azobis(2-amidinopropane)hydrochloride (AAPH)-induced hemolysis and depletion of intracellular glutathione (GSH) in erythrocytes was studied. The inhibition of hemolysis was dose-dependent, and the esters were significantly more effective than gallic acid. Gallic acid and its esters were compared with regard to their reactivity to free radicals, using the DPPH and AAPH/pyranine free-cell assays, and no significant difference was obtained. Gallic acid and its esters not only failed to inhibit the depletion of intracellular GSH in erythrocytes induced by AAPH but exacerbated it. Similarly, the oxidation of GSH by AAPH or horseradish peroxidase/H(2)O(2) in cell-free systems was exacerbated by gallic acid or gallates. This property could be involved in the recent findings on pro-apoptotic and pro-oxidant activities of gallates in tumor cells. We provide evidence that lipophilicity and not only radical scavenger potency is an important factor regarding the efficiency of antihemolytic substances. PMID:20397726

Ximenes, Valdecir F; Lopes, Mariana G; Petrônio, Maicon Segalla; Regasini, Luis Octavio; Silva, Dulce H Siqueira; da Fonseca, Luiz M

2010-05-12

240

Azelaic Acid Topical  

MedlinePLUS

Azelaic acid gel is used to clear the bumps, lesions, and swelling caused by rosacea (a skin disease that ... redness, flushing, and pimples on the face). Azelaic acid cream is used to treat acne. Azelaic acid ...

241

Acid Lipase Disease  

MedlinePLUS

NINDS Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage Disease, Wolman’s Disease Table of Contents (click to jump ... research is being done? Clinical Trials What is Acid Lipase Disease ? Acid lipase disease occurs when the ...

242

Uric acid test (image)  

MedlinePLUS

Uric acid urine test is performed to check for the amount of uric acid in urine. Urine is collected over a 24 ... testing. The most common reason for measuring uric acid levels is in the diagnosis or treatment of ...

243

Folic Acid and Pregnancy  

MedlinePLUS

... What to Expect Ebola: What to Know Folic Acid and Pregnancy KidsHealth > Parents > Pregnancy & Newborn Center > Your ... before conception and during early pregnancy . About Folic Acid Folic acid, sometimes called folate, is a B ...

244

Plasma amino acids  

MedlinePLUS

Amino acids blood test ... types of methods used to determine the individual amino acids levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

245

N-[[(Mercaptoacetyl)amino]benzoyl]glycines as mucolytic agents.  

PubMed

m- and p-aminobenzoic acids were converted to the title compounds by sequential use of ClCH2COCl, SOCl2, glycine methyl or ethyl ester, AcSK, and hydrolysis. The title compounds and a number of salts were compared for mucolytic activity, toxicity, stability, and hygroscopicity. When compared to N-acetyl-L-cysteine (NAC), the compounds exhibit several times the in vitro mucolytic activity of NAC on a molar basis. The most promising candidate appears to be the sodium salt 3.5H2O 2 of the meta series. PMID:4009614

Martin, T A; Comer, W T

1985-07-01

246

Synthesis and bio-functionalization of multifunctional magnetic Fe(3)O(4)@Y(2)O(3):Eu nanocomposites.  

PubMed

A facile homogenous precipitation method has been developed for the synthesis of multifunctional, magnetic, luminescent nanocomposites with Fe(3)O(4) nanoparticles as the core and europium-doped yttrium oxide (Y(2)O(3):Eu) as the shell. The nanocomposites showed both super-paramagnetic behavior and unique europium fluorescence properties with high emission intensity. Their surface has been modified with a bifunctional ligand, p-aminobenzoic acid (PABA), and further biofunctionalized with biotin; the nanocomposites showed specific targeting for avidin-coupled polystyrene beads. PMID:20357905

Ma, Zhi Ya; Dosev, Dosi; Nichkova, Mikaela; Gee, Shirley J; Hammock, Bruce D; Kennedy, Ian M

2009-01-01

247

Cytotoxic and pro-apoptotic effects of novel ganoderic acid derivatives on human cervical cancer cells in vitro.  

PubMed

Ganoderic acid T, a triterpenic acid produced by Ganoderma lucidum, has demonstrated therapeutic potential for tumor disease. In the current work, ganoderic acid T was modified to produce more effective small-molecule inhibitors of cancer cell proliferation. Moreover, the anticancer effects of three new ganoderic acid T derivatives, i.e., (22S,24E)-3?,15?,22-triacetoxy-5?-lanosta-7,9(11),24-trien-26-oic acid ethyl ester (TLTO-Ee), (22S,24E)-3?,15?,22-triacetoxy-5?-lanosta-7,9(11),24-trien-26-oic acid propyl ester (TLTO-Pe), and (22S,24E)-3?,15?,22-triacetoxy-5?-lanosta-7,9(11),24-trien-26-oic acid amide (TLTO-A), and one known derivative, (22S,24E)-3?,15?,22-triacetoxy-5?-lanosta-7,9(11),24-trien-26-oic acid methyl ester (TLTO-Me), on the cervical cell line HeLa were investigated and compared. MTT assay indicated that, among the tested compounds, TLTO-A displayed the highest inhibitory effect on the growth of HeLa cells, whereas it showed less cytotoxicity to the non-tumorous cell line MCF-10A than ganoderic acid T. Flow cytometry analysis revealed that all the compounds caused cell cycle arrest at the G1 phase and induced apoptosis. Furthermore, they decreased the mitochondrial membrane potential and enhanced the activities of pro-apoptotic factors caspase-3 and caspase-9 in a dose-dependent manner. Accordingly, the apoptosis induction was presumed to occur through the endogenous pathway. The following order ranks both cytotoxic and pro-apoptotic effects of the compounds against HeLa cells: TLTO-A>ganoderic acid T?TLTO-Me?TLTO-Ee?TLTO-Pe. This study suggests that the carboxyl group of ganoderic acid T is not the main active group and is suitable for its further structural modification. The current work presents valuable information on the design of ganoderic acid T derivatives to develop potential chemotherapy agents. PMID:22366428

Liu, Ru-Ming; Li, Ying-Bo; Zhong, Jian-Jiang

2012-04-15

248

Acid-Base Equilibria  

NSDL National Science Digital Library

This 9-page PDF document is part of an environmental geochemistry course taught by Dr. David Sherman at the University of Bristol. Topics include acid-base theories, aqueous systems, strong and weak acids and bases, acid-base properties of minerals, the pH of weak acid and buffered systems, and the calculation of titration curves.

Sherman, David W.; Bristol, University O.

249

Stereospecific ligands and their complexes. XXII. Synthesis and antitumor activity of palladium(II) complexes with some esters of (S,S)-ethylenediamine-N,N'-di-(2,2'-di(4-hydroxy-benzyl))-acetic acid.  

PubMed

Four new ligands and their palladium(II) complexes of general formula R2-S,S-eddtyr (L1-L4) and [PdCl2(R2-S,S-eddtyr)] (C1-C4) (R=ethyl, n-propyl, n-butyl and n-pentyl; S,S-eddtyr·2HCl=ethylenediamine-N,N'-di-(2,2'-di(4-hydroxy-benzyl))-acetic acid dihydrochloride have been synthesized and characterized by microanalysis, infrared, (1)H and (13)C NMR spectroscopy. Cytotoxicity for ligands and complexes on two different cell lines (human breast cancer, MDA-MB-231 and human lung cancer, A549 cell lines) and human chronic lymphocytic leukemia cells (CLL) was investigated using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. PMID:25528678

Stojkovi?, Danijela Lj; Jevti?, Verica V; Radi?, Gordana P; Todorovi?, Danijela V; Petrovi?, Marija; Zari?, Milan; Nikoli?, Ivana; Baski?, Dejan; Trifunovi?, Sre?ko R

2015-02-01

250

Detection of bound phenolic acids: prevention by ascorbic acid and ethylenediaminetetraacetic acid of degradation of phenolic acids during alkaline hydrolysis  

Microsoft Academic Search

The experimental conditions commonly used to detect bound phenolic acids by alkaline hydrolysis result in loss of several phenolic acids, particularly dihydroxy-derivatives (caffeic acid, dihydrocaffeic acid, homogentisic acid). In this study we show that the addition of ascorbic acid, a strong antioxidant, and ethylenediaminetetraacetic acid, a metal chelator, totally prevent the loss of phenolic acids during alkaline hydrolysis. In these

M Nardini; E Cirillo; F Natella; D Mencarelli; A Comisso; C Scaccini

2002-01-01

251

Acids and Bases (Netorials)  

NSDL National Science Digital Library

Acids and Bases: this is a resource in the collection "Netorials". In this module there is an introduction to the chemical properties of acids and bases. Afterwards, the sections include topics such as Molecular Structures of Acids and Bases, Ionization constants, properties of salts, buffers and Lewis theory of Acids and Bases. The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

252

Acid tolerance in amphibians  

SciTech Connect

Studies of amphibian acid tolerance provide information about the potential effects of acid deposition on amphibian communities. Amphibians as a group appear to be relatively acid tolerant, with many species suffering increased mortality only below pH 4. However, amphibians exhibit much intraspecific variation in acid tolerance, and some species are sensitive to even low levels of acidity. Furthermore, nonlethal effects, including depression of growth rates and increases in developmental abnormalities, can occur at higher pH.

Pierce, B.A.

1985-04-01

253

Hydrogen Bonded Multilayer Films Based on Poly(2-oxazoline)s and Tannic Acid.  

PubMed

In recent years, the layer-by-layer (LbL) assembly based on hydrogen bonding interactions is gaining popularity for the preparation of thin film coatings, especially for biomedical purposes, based on the use of neutral, non-toxic building blocks. The use of tannic acid (TA) as hydrogen bonding donor is especially interesting as it results in LbL films that are stable under physiological conditions. In this work, investigations on the LbL thin film preparation of TA with poly(2-oxazoline)s with varying hydrophilicity, namely poly(2-methyl-2-oxazoline) (PMeOx), poly(2-ethyl-2-oxazoline) (PEtOx) and poly(2-n-propyl-2-oxazoline) (PnPropOx), are reported. The LbL assembly process is investigated by quartz crystal microbalance and UV-vis spectroscopy revealing linear growth of the film thickness. Furthermore, isothermal titration calorimetry demonstrates the LbL assembly of TA, and PMeOx is found to be mostly enthalpy driven while the LbL assembly of TA with PEtOx and PnPropOx is mostly entropy driven. Finally, scanning electron microscopy and ellipsometry demonstrate the formation of smooth thin films for LbL assembly of TA with all three polymers. Such poly(2-oxazoline) coatings have high potential for use as anti-biofouling coatings. PMID:25274164

Sundaramurthy, Anandhakumar; Vergaelen, Maarten; Maji, Samarendra; Auzély-Velty, Rachel; Zhang, Zhiyue; De Geest, Bruno G; Hoogenboom, Richard

2014-12-01

254

Transport and killing mechanism of a novel camptothecin-deoxycholic acid derivate on hepatocellular carcinoma cells.  

PubMed

Abstract Camptothecin-20(s)-O-glycine ester-[N-(3'?, 12'?-dihydroxy-24'-carbonyl-5'?-cholan)] (A2), 10-(3'?,12'?-dihydroxy-5'?-cholan-24'-carboxyl)-(20?s)-camptothecin (C2), and 10-O-(3-O-(3'?, 12'?-dihydroxy-24'-carbonyl-5'?-cholan)-propyl)-(20S)-camptothecin (D2) are novel camptothecin-deoxycholic acid analogues. MTT assays were performed to assess the anticancer activity of these compounds against hepatocellular carcinoma SMMC-7721, breast carcinoma MCF-7, and colorectal carcinoma HCT-116 cells. A2 had a high killing ability on SMMC-7721 cells selectively, but C2 and D2 did not exhibit selectivity with regard to SMMC-7721 killing. Uptake assays were performed in an effort to elucidate the transport mechanisms of A2 into SMMC-7721 cells. A2 increased the mRNA expression of OATP1B3 (an organic anion-transporting polypeptide) and uptake of A2 was inhibited by rifampin (inhibitor of OATP1B3), which indicated that the transporter-mediated transport of A2 was mediated by OATP1B3. In addition, according to the western blot and apoptosis assays, we found that A2 killed SMMC-7721 cells by inducing cell apoptosis mainly via an AIF (apoptosis-inducing factor) pathway and a caspase-dependent mitochondria apoptosis pathway. PMID:24725118

Li, Qingyong; Liu, Tianyu; Li, Yunchao; Luo, Shuyue; Zhu, Qiaochu; Zhang, Li; Zhao, Tengfei

2014-07-01

255

Synthesis and evaluation of novel [alpha]-heteroaryl-phenylpropanoic acid derivatives as PPAR[alpha/gamma] dual agonists  

SciTech Connect

The synthesis of a new series of phenylpropanoic acid derivatives incorporating an heteroaryl group at the {alpha}-position and their evaluation for binding and activation of PPAR{alpha} and PPAR{gamma} are presented in this report. Among the new compounds, (S)-3-{l_brace}4-[3-(5-methyl-2-phenyl-oxazol-4-yl)-propyl]-phenyl{r_brace}-2-1,2,3-triazol-2-yl-propionic acid (17j), was identified as a potent human PPAR{alpha}/{gamma} dual agonist (EC{sub 50} = 0.013 and 0.061 {micro}M, respectively) with demonstrated oral bioavailability in rat and dog. 17j was shown to decrease insulin levels, plasma glucose, and triglycerides in the ZDF female rat model. In the human apolipoprotein A-1/CETP transgenic mouse model 17j produced increases in hApoA1 and HDL-C and decreases in plasma triglycerides. The increased potency for binding and activation of both PPAR subtypes observed with 17j when compared to previous analogs in this series was explained based on results derived from crystallographic and modeling studies.

Casimiro-Garcia, Agustin; Bigge, Christopher F.; Davis, Jo Ann; Padalino, Teresa; Pulaski, James; Ohren, Jeffrey F.; McConnell, Patrick; Kane, Christopher D.; Royer, Lori J.; Stevens, Kimberly A.; Auerbach, Bruce; Collard, Wendy; McGregor, Christine; Song, Kun; Pfizer

2010-09-27

256

An arylaminopyridazine derivative of gamma-aminobutyric acid (GABA) is a selective and competitive antagonist at the GABAA receptor site.  

PubMed Central

In view of finding a new gamma-aminobutyric acid (GABA) receptor ligand we synthesized an arylaminopyridazine derivative of GABA, SR 95103 [2-(carboxy-3'-propyl)-3-amino-4-methyl-6-phenylpyridazinium chloride]. SR 95103 displaced [3H]GABA from rat brain membranes with an apparent Ki of 2.2 microM and a Hill number near 1.0. SR 95103 (1-100 microM) antagonized the GABA-mediated enhancement of [3H]diazepam binding in a concentration-dependent manner without affecting [3H]diazepam binding per se. SR 95103 competitively antagonized GABA-induced membrane depolarization in rat spinal ganglia. In all these experiments, the potency of SR 95103 was close to that of bicuculline. SR 95103 (100 microM) did not interact with a variety of central receptors--in particular the GABAB, the strychnine, and the glutamate receptors--did not inhibit Na+-dependent synaptosomal GABA uptake, and did not affect GABA-transaminase and glutamic acid decarboxylase activities. Intraperitoneally administered SR 95103 elicited clonicotonic seizures in mice (ED50 = 180 mg/kg). On the basis of these results it is postulated that St 95103 is a competitive antagonist of GABA at the GABAA receptor site. In addition to being an interesting lead structure for the search of GABA ligands, SR 95103 could also be a useful tool to investigate GABA receptor subtypes because it is freely soluble in water and chemically stable. Images PMID:2984669

Chambon, J P; Feltz, P; Heaulme, M; Restle, S; Schlichter, R; Biziere, K; Wermuth, C G

1985-01-01

257

Chlorogenic acid and caffeic acid are absorbed in humans  

Microsoft Academic Search

Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phenolic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of cardiovascular disease. However, data on the absorption of chlorogenic acid and caffeic acid in humans are lacking. We

M. R. Olthof; P. C. H. Hollman; M. B. Katan

2001-01-01

258

Chlorogenic Acid and Caffeic Acid Are Absorbed in Humans1  

Microsoft Academic Search

Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phenolic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of cardiovascular disease. However, data on the absorption of chlorogenic acid and caffeic acid in humans are lacking. We

Margreet R. Olthof; Peter C. H. Hollman; Martijn B. Katan

259

Purification of oleic acid and linoleic acid  

SciTech Connect

To permit kinetic studies of the reactivity of unsaturated fatty acids towards oxygen radicals, it is essential to remove traces of hydroperoxides and other conjugated lipid impurities commonly present in commercial samples. Removal of these impurities has been satisfactorily achieved for oleic and linoleic acids by anaerobic low temperature recrystallization from acetonitrile. The uv spectra of commercial and purified samples are compared.

Arudi, R.L.; Sutherland, M.W.; Bielski, B.H.J.

1983-01-01

260

Acid Thunder: Acid Rain and Ancient Mesoamerica  

ERIC Educational Resources Information Center

Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

Kahl, Jonathan D. W.; Berg, Craig A.

2006-01-01

261

Acid Functionalized Mesoporous Ordered Materials for the Production of 5-Hydroxymethyfurfural from Carbohydrates  

NASA Astrophysics Data System (ADS)

Solid acid catalysts were designed for the conversion of fructose to 5-hydroxymethylfurfural (HMF). Some of the catalysts incorporate thioether groups to promote the tautomerization of fructose to its furanose form, as well as sulfonic acid groups to catalyze its dehydration. A bifunctional silane, 3-((3-(trimethoxysilyl)propyl)thio)propane-1-sulfonic acid (TESAS), was designed for incorporation into SBA-15-type silica by co-condensation. To achieve mesopore ordering in the functionalized silica, the standard SBA-15 synthetic protocol was modified, resulting in well-formed hexagonal particles. Functional groups incorporated into mesoporous silica by co-condensation are more robust under the reaction conditions than those grafted onto a non-porous silica. In a variation, the thioether group of TESAS was oxidized by H2O 2 to the sulfone during the synthesis of the modified SBA-15. The materials were tested in batch reactors and compared in the selective dehydration of fructose to 5-hydroxymethylfurfural (HMF). Compared to benchmark catalysts, the thioether-containing TESAS-SBA-15 showed the highest activity in the dehydration of aqueous fructose, as well as the highest selectivity towards HMF (71 % at 84 % conversion). In addition, the stability of several supported acid catalysts was evaluated in tubular reactors designed to produce 5-hydroxymethylfurfural (HMF) continuously. The reactors, packed with the solid catalysts, were operated at 403 K for extended periods, up to 180 h. The behaviors of three propylsulfonic acid-functionalized, ordered porous silicas (one inorganic SBA-15-type silica, and two ethane-bridged SBA-15-type organosilicas) were compared with that of a propylsulfonic acid-modified, non-ordered porous silica. The HMF selectivity of the catalysts with ordered pore structures ranged from 60 to 75 %, while the selectivity of the non-ordered catalyst peaked at 20 %. The latter was also the least stable, deactivating with a first-order rate constant of 0.152 h-1. The organosilicas are more hydrothermally stable and maintained a steady catalytic activity longer than inorganic SBA-15-type silica. The organosilica with an intermediate framework ethane content of 45 mol % was the most stable, with a first-order deactivation rate constant of only 0.012 h-1. Deactivation under flow conditions is caused primarily by hydrolytic cleavage of acid sites, which can be (to some extent) recaptured by the free surface hydroxyl groups of the silica surface.

Crisci, Anthony J.

262

Fatty acid metabolism and cell proliferation. V. Evaluation of pathways for the generation of lipid peroxides.  

PubMed

Primary cultures of smooth muscle cells were established from the medial layer of guinea pig aorta. Confluent cells at passage level 4-6 were challenged with arachidonic acid and treated with a number of antioxidants and inhibitors of specific lipid peroxidation pathways. Lipid peroxidation was measured by the thiobarbituric acid test for malondialdehyde (MDA) and the isolation of hydroperoxy fatty acids (HPETE) by high performance liquid chromatography (HPLC). Prostanoids were measured by radioimmunoassay and the separation of labeled compounds by HPLC. MDA, 6-keto-PGF1 alpha, and PGE2 were formed when cells were challenged with arachidonic acid and these cells synthesized small amounts of one HPETE isomer, 15-HPETE. The HPETE isomers characteristic of the lipoxygenase pathway, 12-HPETE and 5-HPETE, were not detected. Furthermore, the lipoxygenase inhibitors, eicosatetraynoic acid (ETYA) and 6,7-dihydroxycoumarin (Esculetin), did not block MDA formation. These data show that MDA is not generated in the cells by a lipoxygenase pathway. The cyclooxygenase inhibitors, indomethacin and ETYA, did not block MDA formation but these agents blocked the formation of 15-HPETE. These data show both that 15-HPETE is generated by a cooxidation pathway and that 15-HPETE and cooxidation are not involved in MDA formation. Three inhibitors of cytochrome P450 linked lipid peroxidation, 2-amino-3-ethoxycarbonyl-6-benzyl-4, 5,6,7-tetrahydrothieno-[2,3-C]-pyridine (Tinoridine), 3-methyl-1,2-di-3-pyridyl-1-propanone (Metyrapone) and phenobarbital, did not block MDA formation. These data support earlier studies that indicated that MDA is not generated by a P450 pathway. Cells contained a bound precursor that decomposed to MDA when cells were treated with Fe3+. The cells exhibited autofluorescence and concentric lamellae in lipid droplets that are characteristic of ceroid-lipofuscin. These observations are consistent with lipid peroxidation through increased peroxisomal activity leading to the generation of MDA and the accumulation of ceroid-lipofuscin. The natural antioxidants, vitamin E and vitamin E quinone (EQ), and the synthetic antioxidants, butylated hydroxytoluene and nordihydroguaiaretic acid (NDGA), alpha-naphthol (alpha-N) and propyl gallate (PrGa), all blocked MDA formation in confluent smooth muscle cells, showing that these antioxidants did not function solely as specific inhibitors of lipoxygenase, cooxidation or P450 pathways. Cell proliferation was measured in cells challenged with arachidonic acid and treated with antioxidants and other inhibitors. The least cytotoxic and most potent antioxidant, EQ, blocked MDA formation in confluent cells and promoted grow PMID:6429469

Morisaki, N; Lindsey, J A; Stitts, J M; Zhang, H; Cornwell, D G

1984-06-01

263

Acid-fast stain  

MedlinePLUS

The acid-fast stain is a laboratory test that determines if a sample of tissue, blood, or other body ... dye. The slide is then washed with an acid solution and a different stain is applied. Bacteria ...

264

Aminocaproic Acid Injection  

MedlinePLUS

Aminocaproic acid injection is used to control bleeding that occurs when blood clots are broken down too quickly. This ... the baby is ready to be born). Aminocaproic acid injection is also used to control bleeding in ...

265

Hydrochloric acid poisoning  

MedlinePLUS

Hydrocholoric acid is a clear, poisonous liquid. It is highly corrosive, which means it immediately causes severe damage, such ... poisoning due to swallowing or breathing in hydrochloric acid. This is for information only and not for ...

266

Uric acid - blood  

MedlinePLUS

Uric acid is a chemical created when the body breaks down substances called purines. Purines are found in some ... dried beans and peas, and beer. Most uric acid dissolves in blood and travels to the kidneys. ...

267

Zoledronic Acid Injection  

MedlinePLUS

Zoledronic acid (Reclast) is used to prevent or treat osteoporosis (condition in which the bones become thin and weak ... of life,' end of regular menstrual periods). Zoledronic acid (Reclast) is also used to treat osteoporosis in ...

268

Sulfuric acid poisoning  

MedlinePLUS

Sulfuric acid is a very strong chemical that is corrosive. Corrosive means it can cause severe burns and ... or mucous membranes. This article discusses poisoning from sulfuric acid. This is for information only and not for ...

269

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

270

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

271

The Acid Rain Reader.  

ERIC Educational Resources Information Center

A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

Stubbs, Harriett S.; And Others

272

[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

273

Neutralizing Acids and Bases  

NSDL National Science Digital Library

Learners 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. Use this as a follow-up activity to the related activity, "Color Changes with Acids and Bases."

2012-04-08

274

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

275

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

276

Nucleic acid detection compositions  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann (Madison, WI); Dahlberg, James L. (Madison, WI)

2008-08-05

277

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

278

Cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Waunakee, WI); Lyamichev, Victor I. (Madison, WI); Brow; Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

2010-11-09

279

Cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor L. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

2007-12-11

280

Cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

2000-01-01

281

4-[18F]Fluoro-N-methyl-N-(propyl-2-yn-1-yl)benzenesulfonamide ([18F]F-SA): a versatile building block for labeling of peptides, proteins and oligonucleotides with fluorine-18 via Cu(I)-mediated click chemistry.  

PubMed

Cu(I)-mediated [3+2]cycloaddition between azides and alkynes has evolved into a valuable bioconjugation tool in radiopharmaceutical chemistry. We have developed a simple, convenient and reliable radiosynthesis of 4-[18F]fluoro-N-methyl-N-(propyl-2-yn-1-yl)benzenesulfonamide ([18F]F-SA) as a novel aromatic sulfonamide-based click chemistry building block. [18F]F-SA could be prepared in a remotely controlled synthesis unit in 32 ± 5% decay-corrected radiochemical yield in a total synthesis time of 80 min. The determined lipophilicity of [18F]F-SA (logP = 1.7) allows handling of the radiotracer in aqueous solutions. The versatility of [18F]F-SA as click chemistry building block was demonstrated by the labeling of a model peptide (phosphopeptide), protein (HSA), and oligonucleotide (L-RNA). The obtained radiochemical yields were 77% (phosphopeptide), 55-60% (HSA), and 25% (L-RNA), respectively. Despite the recent emergence of a multitude of highly innovative novel bioconjugation methods for 18F labeling of biopolymers, Cu(I)-mediated click chemistry with [18F]F-SA represents a reliable, robust and efficient radiolabeling technique for peptides, proteins, and oligonucleotides with the short-lived positron emitter 18F. PMID:23306450

Ramenda, Theres; Steinbach, Jörg; Wuest, Frank

2013-04-01

282

Structural Modifications of Neuroprotective Anti-Parkinsonian (?)-N6-(2-(4-(Biphenyl-4-yl)piperazin-1-yl)-ethyl)-N6-propyl-4,5,6,7-tetrahydrobenzo[d]thiazole-2,6-diamine (D-264): An Effort toward the Improvement of in Vivo Efficacy of the Parent Molecule  

PubMed Central

In our overall goal to develop multifunctional dopamine D2/D3 agonist drugs for the treatment of Parkinson’s disease (PD), we previously synthesized potent D3 preferring agonist D-264 (1a), which exhibited neuroprotective properties in two animal models of PD. To enhance the in vivo efficacy of 1a, a structure–activity relationship study was carried out. Competitive binding and [35S]GTP?S functional assays identified compound (?)-9b as one of the lead molecules with preferential D3 agonist activity (EC50(GTP?S); D3 = 0.10 nM; D2/D3 (EC50): 159). Compounds (?)-9b and (?)-8b exhibited high in vivo activity in two PD animal models, reserpinized and 6-hydroxydopamine (OHDA)-induced unilateral lesioned rats. On the other hand, 1a failed to show any in vivo activity in these models unless the compound was dissolved in 5–10% beta-hydroxy propyl cyclodextrin solution. Lead compounds exhibited appreciable radical scavenging activity. In vitro experiments with dopaminergic MN9D cells indicated neuroprotection by both 1a and (?)-9b from toxicity of MPP+. PMID:24471976

2015-01-01

283

[Biosynthesis of adipic acid].  

PubMed

Adipic acid is a six-carbon dicarboxylic acid, mainly for the production of polymers such as nylon, chemical fiber and engineering plastics. Its annual demand is close to 3 million tons worldwide. Currently, the industrial production of adipic acid is based on the oxidation of aromatics from non-renewable petroleum resources by chemo-catalytic processes. It is heavily polluted and unsustainable, and the possible alternative method for adipic acid production should be developed. In the past years, with the development of synthetic biology and metabolic engineering, green and clean biotechnological methods for adipic acid production attracted more attention. In this study, the research advances of adipic acid and its precursor production are reviewed, followed by addressing the perspective of the possible new pathways for adipic acid production. PMID:24432653

Han, Li; Chen, Wujiu; Yuan, Fei; Zhang, Yuanyuan; Wang, Qinhong; Ma, Yanhe

2013-10-01

284

The linoleic acid and trans fatty acids of margarines1  

Microsoft Academic Search

Fifty brands of margarine were analysed for cis-polyunsaturated acids by lipox- idase, for trans fatty acid by infrared spectroscopy, and for fatty acid composition by gas-liquid chromatography. High concentrations of trans fatty acids tended to be associated with low concentrations of hinoleic acid. Later analyses on eight of the brands, representing various proportions of linoleic to trans fatty acids, indicated

J. L. Beare-Rogers; L. M. Gray; R. Hollywood

285

Process for the preparation of lactic acid and glyceric acid  

DOEpatents

Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

2008-12-02

286

Microorganisms for producing organic acids  

SciTech Connect

Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

Pfleger, Brian Frederick; Begemann, Matthew Brett

2014-09-30

287

The Competing Effects of Hyaluronic and Methacrylic Acid in Model Contact Lenses.  

PubMed

The aim of this study was to determine the influence of hyaluronic acid (HA) on lysozyme sorption in model contact lenses containing varying amounts of methacrylic acid (MAA). One model conventional hydrogel (poly(2-hydroxyethyl methacrylate) (pHEMA)) and two model silicone hydrogels (pHEMA, methacryloxypropyltris(trimethylsiloxy)silane (pHEMA TRIS) and N,N-dimethylacrylamide, TRIS (DMAA TRIS)) lens materials were prepared with and without MAA at two different concentrations (1.7 and 5%). HA, along with dendrimers, was loaded into these model contact lens materials and then cross-linked with 1-ethyl-3-(3-dimethylamino propyl)-carbodiimide (EDC). Equilibrium water content (EWC), advancing water contact angle and lysozyme sorption on these lens materials were investigated. In the HA-containing materials, the presence (P<0.05) and amount (P<0.05) of MAA increased the EWC of the materials. For most materials, addition of MAA reduced the advancing contact angles (P<0.05) and for all the materials, the addition of HA further improved hydrophilicity (P<0.05). For the non-HA containing hydrogels, the presence (P<0.05) and amount (P<0.05) of MAA increased lysozyme sorption. The presence of HA decreased lysozyme sorption for all materials (P<0.05). MAA appears to work synergistically with HA to increase the EWC in addition to improving the hydrophilicity of model pHEMA-based and silicone hydrogel contact lens materials. Hydrogel materials that contain HA have tremendous potential as hydrophilic, protein-resistant contact lens materials. PMID:21477462

Weeks, Andrea; Subbaraman, Lakshman N; Jones, Lyndon; Sheardown, Heather

2011-04-01

288

Preparation of Some Substituted Terephthalic Acids  

E-print Network

Preparation of Some Substituted Terephthalic Acids Susanna Branion and Vladimir Benin Department substituted terephthalic acids: 2-sulfomethylterephthalic acid (1) and 2-phosphonoterephthalic acid (2 for construction of acid-pendant polymer chains. Keywords: Acid-pendant polymers, arenephosphonic acids

Benin, Vladimir

289

4, 29012944, 2007 Acid deposition,  

E-print Network

HESSD 4, 2901­2944, 2007 Acid deposition, climate change and acid extremes C. D. Evans et al. Title System Sciences Effects of decreasing acid deposition and climate change on acid extremes in an upland, 2901­2944, 2007 Acid deposition, climate change and acid extremes C. D. Evans et al. Title Page

Boyer, Edmond

290

Tyrosine-based 1-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine and -adenine ((S)-HPMPC and (S)-HPMPA) prodrugs: synthesis, stability, antiviral activity, and in vivo transport studies.  

PubMed

Eight novel single amino acid (6-11) and dipeptide (12, 13) tyrosine P-O esters of cyclic cidofovir ((S)-cHPMPC, 4) and its cyclic adenine analogue ((S)-cHPMPA, 3) were synthesized and evaluated as prodrugs. In vitro IC(50) values for the prodrugs (<0.1-50 ?M) vs vaccinia, cowpox, human cytomegalovirus, and herpes simplex type 1 virus were compared to those for the parent drugs ((S)-HPMPC, 2; (S)-HPMPA, 1; IC(50) 0.3-35 ?M); there was no cytoxicity with KB or HFF cells at ?100 ?M. The prodrugs exhibited a wide range of half-lives in rat intestinal homogenate at pH 6.5 (<30-1732 min) with differences of 3-10× between phostonate diastereomers. The tyrosine alkylamide derivatives of 3 and 4 were the most stable. (l)-Tyr-NH-i-Bu cHPMPA (11) was converted in rat or mouse plasma solely to two active metabolites and had significantly enhanced oral bioavailability vs parent drug 1 in a mouse model (39% vs <5%). PMID:21812420

Zakharova, Valeria M; Serpi, Michaela; Krylov, Ivan S; Peterson, Larryn W; Breitenbach, Julie M; Borysko, Katherine Z; Drach, John C; Collins, Mindy; Hilfinger, John M; Kashemirov, Boris A; McKenna, Charles E

2011-08-25

291

Tyrosine-Based 1-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine and -adenine ((S)-HPMPC and (S)-HPMPA) Prodrugs: Synthesis, Stability, Antiviral Activity and in Vivo Transport Studies  

PubMed Central

Eight novel single amino acid (6–11) and dipeptide (12, 13) tyrosine P-O esters of cyclic cidofovir ((S)-cHPMPCa, 4) and its cyclic adenine analog ((S)-cHPMPA, 3) were synthesized and evaluated as prodrugs. In vitro IC50 values for the prodrugs vs vaccinia, cowpox, human cytomegalo- and herpes simplex type 1 viruses were similar to those for the parent drugs ((S)-HPMPC, 2, (S)-HPMPA, 1; IC50 0.3 – 30 µM); there were no cytoxicity with KB or HFF cells at ? 100 µM. The prodrugs exhibited a wide range of half-lives in rat intestinal homogenate at pH 6.5 (<30 – 1732 min) with differences of 3–10× between phostonate diastereomers. The tyrosine-alkylamide derivatives of 3 and 4 were the most stable. (L)-Tyr-NHiBu cHPMPA (11) was converted in rat or mouse plasma solely to two active metabolites and had significantly enhanced oral bioavailability vs parent drug 1 in a mouse model (39 % vs <5 %). PMID:21812420

Zakharova, Valeria M.; Serpi, Michaela; Krylov, Ivan S.; Peterson, Larryn W.; Breitenbach, Julie M.; Borysko, Katherine Z.; Drach, John C.; Collins, Mindy; Hilfinger, John M.; Kashemirov, Boris A.; McKenna, Charles E.

2011-01-01

292

Palladium(II) complexes with R(2)edda derived ligands. Part IV. O,O'-dialkyl esters of (S,S)-ethylenediamine-N,N'-di-2-(4-methyl)-pentanoic acid dihydrochloride and their palladium(II) complexes: synthesis, characterization and in vitro antitumoral activity against chronic lymphocytic leukemia (CLL) cells.  

PubMed

Four novel bidentate N,N'-ligand precursors, including O,O'-dialkyl esters (alkyl = ethyl, n-propyl, n-butyl and n-pentyl), L1 x 2 HCl-L4 x 2 HCl, of (S,S)-ethylenediamine-N,N'-di-2-(4-methyl)-pentanoic acid dihydrochloride [(S,S)-H(4)eddl]Cl(2) and the corresponding palladium(II) complexes 1-4, were prepared and characterized by IR, (1)H NMR and (13)C NMR spectroscopy and elemental analysis. In vitro cytotoxicity of all compounds was determined against chronic lymphocytic leukemia cells (CLL). The compounds were found to exhibit higher antitumoral activity than cisplatin. The most active compound 2, [PdCl(2){(S,S)-nPr(2)eddl}], was found to be 13.6 times more active than cisplatin on CLL cells. PMID:20570025

Vuji?, Jelena M; Cvijovi?, Milica; Kaluderovi?, Goran N; Milovanovi?, Marija; Zmejkovski, Bojana B; Volarevi?, Vladislav; Arsenijevi?, Nebojsa; Sabo, Tibor J; Trifunovi?, Sre?ko R

2010-09-01

293

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

294

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.

295

THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE  

EPA Science Inventory

This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

296

CHRONIC ADMINISTRATION OF DOCOSAHEXAENOIC ACID OR EICOSAPENTAENOIC ACID, BUT NOT ARACHIDONIC ACID,  

E-print Network

, with UMP plus the omega-3 fatty acid docosa- hexaenoic acid (given by gavage), produces substantial in/or, by gavage, an omega-3 (docosahexae- noic or eicosapentaenoic acid) or omega-6 (arachidonic acid) fatty acid. Both of the omega-3 fatty acids elevated major brain phosphatide levels (by 18­28%, and 21­27%) and giv

Wurtman, Richard

297

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

298

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

299

Kidney amino acid transport  

Microsoft Academic Search

Near complete reabsorption of filtered amino acids is a main specialized transport function of the kidney proximal tubule.\\u000a This evolutionary conserved task is carried out by a subset of luminal and basolateral transporters that together form the\\u000a transcellular amino acid transport machinery similar to that of small intestine. A number of other amino acid transporters\\u000a expressed in the basolateral membrane

François Verrey; Dustin Singer; Tamara Ramadan; Raphael N. Vuille-dit-Bille; Luca Mariotta; Simone M. R. Camargo

2009-01-01

300

Diterpenoid acids from Grindelia nana.  

PubMed

Two new norditerpenoid acids of the labdane-type (norgrindelic acids), 4,5-dehydro-6-oxo-18-norgrindelic acid (1) and 4beta-hydroxy-6-oxo-19-norgrindelic acid (2), as well as a new grindelic acid derivative, 18-hydroxy-6-oxogrindelic acid (3), were isolated from the aerial parts of Grindelia nana. In addition, the known compounds, 6-oxogrindelic acid, grindelic acid, methyl grindeloate, 7alpha,8alpha-epoxygrindelic acid, and 4alpha-carboxygrindelic acid were also isolated. The structures of the new compounds were characterized on the basis of spectroscopic analysis. PMID:10757723

Mahmoud, A A; Ahmed, A A; Tanaka, T; Iinuma, M

2000-03-01

301

Detection of marine microalgal biotoxins using bioassays based on functional expression of tunicate xenobiotic receptors in yeast.  

PubMed

Marine microalgae can produce biotoxins that cause widespread poisoning in marine ecosystems and may also affect human health. While established microalgal biotoxins are detectable using chemical methods, a need remains for robust, inexpensive bioassays. Ligand-binding domains (LBDs) from a tunicate nuclear receptor, VDR/PXR?, which is orthologous to both the vertebrate pregnane X receptor (PXR) and the vitamin D receptor (VDR), can be activated by microalgal biotoxins when expressed in mammalian cell lines. Building on this observation, we developed a generic recombinant yeast bioassay platform that expresses chimeric proteins containing tunicate VDR/PXR? LBDs which mediate ligand-dependent transcription of a reporter gene (lacZ) encoding an easily assayed enzyme (?-galactosidase). Recombinant yeast strains expressing VDR/PXR? LBDs from two tunicate species, Ciona intestinalis and Botryllus schlosseri, were exposed to both synthetic and natural toxins. Structurally simple synthetic chemicals (n-butyl-p-aminobenzoate, carbamazepine, p-aminobenzoic acid, and bisphenol-A) generated EC50 values in the ?M range, while more structurally complex marine biotoxins (okadaic acid, pectenotoxin-11, and portimine) activated the assays in the nM range. Given the large number of tunicate species, we propose that tunicate VDR/PXR LBDs may be used as 'sensor elements' in similar yeast-based high-throughput bioassays for detection of established microalgal biotoxins and uncharacterised marine bioactive compounds. PMID:25549942

Richter, Ingrid; Fidler, Andrew E

2015-03-01

302

Effects of butylated hydroxyanisole and butylated hydroxytoluene on DNA adduct formation and arylamine N-acetyltransferase activity in human bladder tumour cells.  

PubMed

In this study, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were used to determine the inhibition of arylamine N-acetyltransferase (NAT) activity and DNA adduct formation in human bladder tumour cell line T-24. The activity of NAT was measured by high-performance liquid chromatography, assaying for the amounts of N-acetyl-2-aminofluorene and N-acetyl-p-aminobenzoic acid and remaining 2-aminofluorene and p-aminobenzoic acid. Human bladder tumour cell line T-24 cytosols and intact cells were used for examining NAT activity and carcinogen-DNA adduct formation. The results demonstrated that NAT activity and 2-aminofluorene-DNA adduct formation in human bladder tumour cells were inhibited and decreased by BHA and BHT in a dose-dependent manner. The effects of BHA and BHT on the values of the apparent K(m) and V(max) also were determined in both systems examined. The results indicated that BHA and BHT decreased the apparent values of K(m) and V(max) from human bladder tumour cells in both cytosol and intact cells. PMID:11807928

Lu, Hsueh-Fu; Wu, Hsi-Chin; Hsia, Te-Chun; Chen, Wen-Chi; Hung, Chi-Fu; Chung, Jing-Gung

2002-01-01

303

Effects of the butylated hydroxyanisole and butylated hydroxytoluene on the DNA adduct formation and arylamines N-acetyltransferase activity in human colon tumor cells.  

PubMed

The effects of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on N-acetyltransferase (NAT) activity were examined using a human colon tumor cell line (colo 205). BHA or BHT were added to the cytosols or to the medium of human colon tumor cells: The NAT activity was measured by high performance liquid chromatography, assaying the amounts of acetylated 2-aminoflluorene (AAF), p aminobenzoic acid (N-Ac-PABA), nonacetylated 2 aminofluorene (AF) and p-aminobenzoic acid (PABA). The NAT activity in the human colon tumor cells and cytosols was suppressed by BHA or BHT in a dose-dependent manner. The apparent values of Km and Vmax of NAT of human colon tumor cells were also decreased by BHA or BHT in cytosols and in intact cells. BHA or BHT may act as a noncompetitive inhibitor. After the incubation of human colon tumor cells with AF in the presence of BHA or BHT, the cells were recovered and DNA was prepared and hydrolysed to nucleotides. Adducted nucleotides were extracted into butanol and AF-DNA adducts were analysed by HPLC. The results also demonstrated that when BHA or BHT was added to the media, a decrease in AF-DNA adduct formation was seen in the human colon tumor cells. The finding of AF-DNA adduct formation in cultured human colon tumor cells suggest the possibility of using cultured cells for assessing arylamine-induced DNA damage. PMID:11396144

Chang, S H; Chen, G W; Yeh, C C; Hung, C F; Lin, S S; Chung, J G

2001-01-01

304

Recovery of organic acids  

DOEpatents

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Verser, Dan W. (Golden, CO); Eggeman, Timothy J. (Lakewood, CO)

2009-10-13

305

USGS Tracks Acid Rain  

USGS Publications Warehouse

The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

1995-01-01

306

Acid Rain Students' Site  

NSDL National Science Digital Library

The EPA developed this colorful website to teach students all about acid rain. First, through clear descriptions and helpful figures users can learn the characteristics of acid rain, its dangers, and how to control it. The website offers an interactive connect-the-dots, word searches, crossword puzzles, and other games. A short movie provides an overview of how the use of coal contributes to acid rain and acid rain's impacts on ecosystems and human health. The website also offers an introduction to the pH scale and tools to measure the pH.

307

Recovery of organic acids  

DOEpatents

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Verser, Dan W. (Menlo Park, CA); Eggeman, Timothy J. (Lakewood, CO)

2011-11-01

308

Biodiesel production by combined fatty acids separation and subsequently enzymatic esterification to improve the low temperature properties.  

PubMed

The poor low-temperature properties of biodiesel, which provokes easy crystallization at low temperature, can cause fuel line plugging and limits its blending amount with petro-diesel. This work aimed to study the production of biodiesel with a new process of improving the low temperature performance of biodiesel. Waste cooking oil was first hydrolyzed into fatty acids (FAs) by 60g immobilized lipase and 240g RO water in 15h. Then, urea complexation was used to divide the FAs into saturated and unsaturated components. The conditions for complexation were: FA-to-urea ratio 1:2 (w/w), methanol to FA ratio 5:1 (v/v), duration 2h. The saturated and unsaturated FAs were then converted to iso-propyl and methyl esters by lipase, respectively. Finally, the esters were mixed together. The CFPP of this mixture was decreased from 5°C to -3°C. Hydrolysis, urea complexation and enzymic catalyzed esterification processes are discussed in this paper. PMID:25441717

Wang, Meng; Nie, Kaili; Cao, Hao; Deng, Li; Wang, Fang; Tan, Tianwei

2014-12-01

309

Synthesis, antitubercular activity and pharmacokinetic studies of some Schiff bases derived from 1-alkylisatin and isonicotinic acid hydrazide (INH).  

PubMed

N'-(1-alkyl-2,3-dihydro-2-oxo-1H-3-indolyliden)-4-pyridinecarboxylic acid hydrazide derivatives, 3(a-g), were synthesized in a trial to overcome the resistance developed with the therapeutic uses of isoniazid (INH). The lipophilicity of the synthesized derivatives supersedes that of the INH as expressed by Clog p values. The synthesized compounds and INH were tested against bovin, human sensitive and human resist strains of Mycobacterium tuberculosis. Compounds 3a, 3d, 3f and 3g with 1-unsubstituted, 1-propyl, 1-propynyl and 1-benzyl groups respectively exhibited equipotent growth inhibitory activity (MIC 10 micromol) against the tested strains as compared with INH however the later has no activity against human resist strain. Pharmacokinetic study revealed that the rate and extent of absorption of the tested derivatives (3d and 3f) significantly higher than that of INH (p < 0.05). The relative bioavailabilities (F(R)%) were 183.15 and 443.25 for 3f and 3d respectively as compared to INH. These results preliminary indicate the possible use of the prepared derivatives for treatment of tuberculosis infections in order to overcome the resistance developed with INH. PMID:14609123

Aboul-Fadl, Tarek; Mohammed, Faragany Abdel-Hamid; Hassan, Ehsan Abdel-Saboor

2003-10-01

310

Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA) Composites: Effect of Coupling Agent Mediated Interface  

PubMed Central

In this study three chemical agents Amino-propyl-triethoxy-silane (APS), sorbitol ended PLA oligomer (SPLA) and Hexamethylene diisocyanate (HDI) were identified to be used as coupling agents to react with the phosphate glass fibre (PGF) reinforcement and the polylactic acid (PLA) polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ? = 20 µm) in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa) was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS) helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP) control, supporting the use of these materials as coupling agent’s within medical implant devices. PMID:24955744

Hasan, Muhammad Sami; Ahmed, Ifty; Parsons, Andrew; Walker, Gavin; Scotchford, Colin

2012-01-01

311

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...

312

EXPOSURES TO ACIDIC AEROSOLS  

EPA Science Inventory

Ambient monitoring of acid aerosol in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. easurements made in Kingston, TN, and Stuebenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m3 more than 10 ti...

313

Amino Acid Crossword Puzzle  

ERIC Educational Resources Information Center

Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

Sims, Paul A.

2011-01-01

314

Acids and Salts (GCMP)  

NSDL National Science Digital Library

Acids and Salts: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore a few properties of common acids and their salts. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

315

Strong Acids (GCMP)  

NSDL National Science Digital Library

Strong Acids: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore the properties of common strong acids. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

316

Acid in water  

NSDL National Science Digital Library

Plants and animals that live in water create some amount of acid in the water. The carbon dioxide that plants and animals release into the water makes the water acidic and unsafe for living organisms. This is why the water of captive aquatic animals and plants must be changed often.

Laszlo Ilyes (None;)

2007-05-16

317

Acids in Proteins  

NSDL National Science Digital Library

This lesson describes how amino acids build proteins in a person's body. Amino acids are the chemical building blocks for the structure of an organism. A link to a quiz is provided at the end of the lesson to check comprehension.

2012-06-19

318

Sealed Lead Acid Batteries  

Microsoft Academic Search

There is a growing trend among users of lead acid batteries towards use of sealed maintenance free designs. These offer the user many advantages in freedom of battery placement, increased safety, battery size and weight, no need to water, and in some instances superior performance. In standby service, two battery types are rivalling the traditional flooded lead acid stationary battery.

J. J. Kelley; C. K. McManus

1986-01-01

319

Acid (and Base) Rainbows  

NSDL National Science Digital Library

Students are introduced to the differences between acids and bases and how to use indicators, such as pH paper and red cabbage juice, to distinguish between them. They learn why it is important for engineers to understand acids and bases.

Integrated Teaching And Learning Program

320

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...

321

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

322

What Causes Acid Rain?  

NSDL National Science Digital Library

The phenomenon is the formation of acid rain. The resource explains the chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air, mix and react with water and other chemicals to form more acidic pollutants that dissolve very easily in water and can be carried long distances where they become part of rain, sleet, snow, and fog.

323

Lead-acid cell  

SciTech Connect

A lead-acid storage battery is described that has a lead negative electrode, a lead dioxide positive electrode and a sulfuric acid electrolyte having an organic catalyst dissolved therein which prevents dissolution of the electrodes into lead sulfate whereby in the course of discharge, the lead dioxide is reduced to lead oxide and the lead is oxidized.

Hradcovsky, R.J.; Kozak, O.R.

1980-12-09

324

Carbolic acid poisoning  

MedlinePLUS

Carbolic acid is a sweet-smelling clear liquid that is added to many different products. Carbolic acid poisoning occurs when someone touches or swallows this chemical. This is for information only and not for use in the treatment or management ...

325

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

326

2-substituted thiazolidine-4(R)-carboxylic acids as prodrugs of L-cysteine. Protection of mice against acetaminophen hepatotoxicity  

SciTech Connect

A number of 2-alkyl- and 2-aryl-substituted thiazolidine-4(R)-carboxylic acids were evaluated for their protective effect against hepatotoxic deaths produced in mice by LD/sub 90/ doses of acetaminophen. 2(RS)-Methyl-, 2(RS)-n-propyl-, and 2(RS)-n- pentylthiazolidine -4(R)-carboxylic acids (compounds 1b,d,e, respectively) were nearly equipotent in their protective effect based on the number of surviving animals at 48 h as well as by histological criteria. 2(RS)-Ethyl-, 2(RS)-phenyl-, and 2(RS)-(4-pyridyl)thiazolidine-4(R)-carboxylic acids (compounds 1c,f,g) were less protective. The enantiomer of 1b, viz., 2(RS)- methylthiazolidine -4(S)-carboxylic acid (2b), was totally ineffective in this regard. Thiazolidine-4(R)-carboxylic acid (1a), but not its enantiomer, 2a, was a good substrate for a solubilized preparation of rat liver mitochondrial proline oxidase (K/sub m/ 1.1 x 10(-4) M; V/sub max/ . 5.4 mumol min-1 (mg of protein)-1). Compound 1b was not a substrate for proline oxidase but dissociated to L-cysteine in this system. At physiological pH and temperature, the hydrogens on the methyl group of 1b underwent deuterium exchange with solvent D/sub 2/O (k1 . 2.5 X 10(-5) s), suggesting that opening of the thiazolidine ring must have taken place. Indeed, 1b labeled with /sup 14/C in the 2 and methyl positions was rapidly metabolized by the rat to produce /sup 14/CO/sub 2/, 80% of the dose being excreted in this form in the expired air after 24 h. It is suggested that these 2-substituted thiazolidine-4(R)-carboxylic acids are prodrugs of L-cysteine that liberate this sulfhydryl amino acid in vivo by nonenzymatic ring opening, followed by solvolysis.

Nagasawa, H.T.; Goon, D.J.; Muldoon, W.P.; Zera, R.T.

1984-05-01

327

Oxophily of gadolinium(III) and synthesis of dissymmetric di(Schiff bases) and dissymmetric dinuclear compounds. Crystal structure of [Cu[sub 2]L[prime](OH)](ClO[sub 4])[sub 2][center dot]H[sub 2]O with L[prime] = 2-[N-(2-pyridylethyl)formimidoyl]-6-[N-((dimethylamino)propyl)formimidoyl]phenolato  

SciTech Connect

The strong oxophilic character of the Gd(III) ion has been utilized to protect one of the carbonyl functions of 2,6-diformyl-4-methylphenol, which has allowed the quantitative synthesis of mono(Schiff bases), then dissymmetric di(Schiff bases). The synthetic process is as follows: the reaction of 2,6-diformyl-4-methylphenol with a primary amine RNH[sub 2] in the presence of Gd(III) affords a complex in which Gd(III) is coordinated to two mono(Schiff bases) through their carbonyl and phenolic oxygen atoms. The mono(Schiff base) may be isolated by precipitation of Gd(III) in the form of gadolinium(III) oxalate. The reaction of another primary amine, R[prime]NH[sub 2], on this mono(Schiff base) affords a dissymmetric di(Schiff base), from which dissymmetric dinuclear compounds can be synthesized. For example, this reaction has been carried out with RNH[sub 2] = 2-(2-aminoethyl)pyridine and R[prime]NH[sub 2] = N,N-dimethylpropylenediamine. The mono(Schiff base) 2-formyl-6-(N-(2-pyridylethyl)formimidoyl)-4-methylphenol (HL) and the di(Schiff base) 2-[N-(2-pyridylethyl)formimidoyl]-6-[N-((dimethylamino)propyl)formimidoyl]-4-methylphenol (HL[prime]) have been unambiguously characterized from their [sup 1]H NMR spectra. The copper(II) dinuclear compound [CuL[prime](OH)](ClO[sub 4])[sub 2][center dot]H[sub 2]O obtained from this di(Schiff base) has been synthesized, and its crystal structure has been solved. 36 refs., 2 figs., 5 tabs.

Andruh, M.; Kahn, O.; Sainton, J. (Universite de Paris Sud, Orsay (France)); Dromzee, Y.; Jeannin, S. (Universite Pierre et Marie Curie, Paris (France))

1993-04-28

328

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

329

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

330

Chemical modification of glycyrrhizic acid as a route to new bioactive compounds for medicine.  

PubMed

Glycyrrhizic Acid (GL) is the major bioactive triterpene glycoside of licorice root (Glycyrrhiza Radix) extracts possessing a wide range of pharmacological properties (anti-inflammatory, anti-ulcer, anti-allergic, anti-dote, anti-oxidant, anti-tumor, anti-viral etc.). Official sources of GL are Glycyrrhiza glabra L. and Gl. uralensis Fish. (Leguminosae). The content of GL in licorice root is 2-24% of the dry weight. GL is one of the leading natural compounds for clinical trials of chronic active viral hepatitis and HIV infections (preparation Stronger Neo-Minophagen C, SNMC), and its monoammonium salt (glycyram, tussilinar) is used as an anti-inflammatory and anti-allergic remedy. The synthetic transformations of GL on carboxyl and hydroxyl groups were carried out to produce new bioactive derivatives for medicine. GL esters were produced containing fragments of bioactive acids (4-nitrobenzoic, cinnamic, salycilic, acetylsalycilic, nicotinic, isonicotinic). Bioactive amides of GL were synthesized using chloroanhydride technique and N,N'-diciclohexylcarbodiimide (DCC) method. The synthesis of acylthioureids and semicarbazones was carried out via the reaction of triacylisothiocianate of penta-O-acetyl-GL with primary amines and hydrazines. The chain of transformations of trichloranhydride of penta-O-acetyl-GL was made with the introduction of diazoketone groups in the molecule. A new group of GL derivatives to be triterpene glycopeptides was prepared by the activated esters method (N-hydrohysuccinimide-DCC or N-hydroxybenzotriazol-DCC) using alkyl (methyl, ethyl, propyl, butyl, tert-butyl) or benzyl (4-nitrobenzyl) esters of amino acids. The glycyrrhizyl analogs of the known immunostimulator, N-acetyl-muramoyldipeptide (MDP), were synthesized using Reagent Woodward K. A series of ureids and carbamates of GL was synthesized containing 5-amino-5-desoxy-D-xylopyranose units. The synthesis of 4-nitro-4-desoxy-glycosides, modified analogs of GL, was carried out by the oxidative splitting of the carbohydrate part of GL with NaIO(4). Triterpene 2-desoxy-D-glycosides, analogs of GL, were prepared by the glycal method in the presence of iodine-containing promoters or sulfonic acid cation-exchange resin KU-2-8 (H+) and LiBr. New anti-inflammatory and anti-ulcer agents were found among GL derivatives such as esters, amides, ureids, carbamates, thioureids and glycopeptides. GL glycopeptides are of interest as immunomodulators. Some of the chemically modified GL derivatives (salts, amides, glycopeptides) were potent HIV-1 and HIV-2 inhibitors in vitro. Preparation niglizin (penta-O-nicotinate of GL) was studied clinically as an anti-inflammatory agent and is of interest for studies as hepatoprotector and HIV inhibitor. PMID:12570715

Baltina, L A

2003-01-01

331

Substrate Specificity and Ligand Interactions of CYP26A1, the Human Liver Retinoic Acid Hydroxylase  

PubMed Central

All-trans-retinoic acid (atRA) is the active metabolite of vitamin A. atRA is also used as a drug, and synthetic atRA analogs and inhibitors of retinoic acid (RA) metabolism have been developed. The hepatic clearance of atRA is mediated primarily by CYP26A1, but design of CYP26A1 inhibitors is hindered by lack of information on CYP26A1 structure and structure-activity relationships of its ligands. The aim of this study was to identify the primary metabolites of atRA formed by CYP26A1 and to characterize the ligand selectivity and ligand interactions of CYP26A1. On the basis of high-resolution tandem mass spectrometry data, four metabolites formed from atRA by CYP26A1 were identified as 4-OH-RA, 4-oxo-RA, 16-OH-RA and 18-OH-RA. 9-cis-RA and 13-cis-RA were also substrates of CYP26A1. Forty-two compounds with diverse structural properties were tested for CYP26A1 inhibition using 9-cis-RA as a probe, and IC50 values for 10 inhibitors were determined. The imidazole- and triazole-containing inhibitors [S-(R*,R*)]-N-[4-[2-(dimethylamino)-1-(1H-imidazole-1-yl)propyl]-phenyl]2-benzothiazolamine (R116010) and (R)-N-[4-[2-ethyl-1-(1H-1,2,4-triazol-1-yl)butyl]phenyl]-2-benzothiazolamine (R115866) were the most potent inhibitors of CYP26A1 with IC50 values of 4.3 and 5.1 nM, respectively. Liarozole and ketoconazole were significantly less potent with IC50 values of 2100 and 550 nM, respectively. The retinoic acid receptor (RAR) ? agonist CD1530 was as potent an inhibitor of CYP26A1 as ketoconazole with an IC50 of 530 nM, whereas the RAR? and RAR? agonists tested did not significantly inhibit CYP26A1. The pan-RAR agonist 4-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl]benzoic acid and the peroxisome proliferator-activated receptor ligands rosiglitazone and pioglitazone inhibited CYP26A1 with IC50 values of 3.7, 4.2, and 8.6 ?M, respectively. These data demonstrate that CYP26A1 has high ligand selectivity but accepts structurally related nuclear receptor agonists as inhibitors. PMID:21521770

Thatcher, Jayne E.; Buttrick, Brian; Shaffer, Scott A.; Shimshoni, Jakob A.; Goodlett, David R.; Nelson, Wendel L.

2011-01-01

332

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

333

Trans Fatty Acids  

NASA Astrophysics Data System (ADS)

Fats and their various fatty acid components seem to be a perennial concern of nutritionists and persons concerned with healthful diets. Advice on the consumption of saturated, polyunsaturated, monounsaturated, and total fat bombards us from magazines and newspapers. One of the newer players in this field is the group of trans fatty acids found predominantly in partially hydrogenated fats such as margarines and cooking fats. The controversy concerning dietary trans fatty acids was recently addressed in an American Heart Association (AHA) science advisory (1) and in a position paper from the American Society of Clinical Nutrition/American Institute of Nutrition (ASCN/AIN) (2). Both reports emphasize that the best preventive strategy for reducing risk for cardiovascular disease and some types of cancer is a reduction in total and saturated fats in the diet, but a reduction in the intake of trans fatty acids was also recommended. Although the actual health effects of trans fatty acids remain uncertain, experimental evidence indicates that consumption of trans fatty acids adversely affects serum lipid levels. Since elevated levels of serum cholesterol and triacylglycerols are associated with increased risk of cardiovascular disease, it follows that intake of trans fatty acids should be minimized.

Doyle, Ellin

1997-09-01

334

WASTE ACID DETOXIFICATION AND RECLAMATION  

EPA Science Inventory

This Environmental Security Technology Certification Program (ESTCP) project demonstrated the Waste Acid Detoxification and Reclamation (WADR) systems ability to recover waste electropolish acid solutions generated during the manufacturing of gun-tubes, and reuse the clean acid. ...

335

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

336

Simple and rapid analytical method for detection of amino acids in blood using blood spot on filter paper, fast-GC/MS and isotope dilution technique.  

PubMed

A simple and rapid method for quantitative analysis of amino acids, including valine (Val), leucine (Leu), isoleucine (Ile), methionine (Met) and phenylalanine (Phe), in whole blood has been developed using GC/MS. In this method, whole blood was collected using a filter paper technique, and a 1/8 in. blood spot punch was used for sample preparation. Amino acids were extracted from the sample, and the extracts were purified using cation-exchange resins. The isotope dilution method using ²H?-Val, ²H?-Leu, ²H?-Met and ²H?-Phe as internal standards was applied. Following propyl chloroformate derivatization, the derivatives were analyzed using fast-GC/MS. The extraction recoveries using these techniques ranged from 69.8% to 87.9%, and analysis time for each sample was approximately 26 min. Calibration curves at concentrations from 0.0 to 1666.7 ?mol/l for Val, Leu, Ile and Phe and from 0.0 to 333.3 ?mol/l for Met showed good linearity with regression coefficients=1. The method detection limits for Val, Leu, Ile, Met and Phe were 24.2, 16.7, 8.7, 1.5 and 12.9 ?mol/l, respectively. This method was applied to blood spot samples obtained from patients with phenylketonuria (PKU), maple syrup urine disease (MSUD), hypermethionine and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), and the analysis results showed that the concentrations of amino acids that characterize these diseases were increased. These results indicate that this method provides a simple and rapid procedure for precise determination of amino acids in whole blood. PMID:20971689

Kawana, Shuichi; Nakagawa, Katsuhiro; Hasegawa, Yuki; Yamaguchi, Seiji

2010-11-15

337

Two new fatty esters from Rhazya stricta roots (Apocynanaceae).  

PubMed

Investigation of roots of Rhazya stricta (Apocynanaceae) of Pakistan origin lead to isolation of two new fatty esters 9-octadecenoic acid-2',3'-dihydroxy propyl ester (1) and hexadecanoic acid-2',3'-dihydroxy propyl ester (2). Linked scan MS measurements were used to propose a mass fragmentation pattern for the fatty ester 9-octadecenoic acid-2',3'-dihydroxy propyl ester. PMID:19023793

Atta-Ur-Rahman; Sultana, Nighat; Shahwar, Durre; Choudhary, Muhammed Iqbal

2008-01-01

338

Folic acid in diet  

MedlinePLUS

... certain types of anemias . Folate works along with vitamin B12 and vitamin C to help the body break ... Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. National Academy Press, ...

339

Amoxicillin and Clavulanic Acid  

MedlinePLUS

... Amoxicillin is in a class of medications called penicillin-like antibiotics. It works by stopping the growth ... allergic to amoxicillin (Amoxil, Trimox, Wymox), clavulanic acid, penicillin, cephalosporins, or any other medications.tell your doctor ...

340

Difficult Decisions: Acid Rain.  

ERIC Educational Resources Information Center

Discusses some of the contributing factors and chemical reactions involved in the production of acid rain, its effects, and political issues pertaining to who should pay for the clean up. Supplies questions for consideration and discussion. (RT)

Miller, John A.; Slesnick, Irwin L.

1989-01-01

341

Alpha Hydroxy Acids  

MedlinePLUS

... cancer cells associated with exposure to light) in mice, and that salicyclic acid had a photoprotective effect (protected against the effects of light) in mice. The complete results of this study are available ...

342

Boric acid poisoning  

MedlinePLUS

... acid poisoning usually occurs when someone swallows powdered roach-killing products that contain the chemical. Chronic poisoning ... and ant pesticides Photography chemicals Powders to kill roaches Some eye wash products Note: This list may ...

343

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...

344

Amino Acids and Chirality  

NASA Technical Reports Server (NTRS)

Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.

Cook, Jamie E.

2012-01-01

345

Facts about Folic Acid  

MedlinePLUS

... For... Media Policy Makers Facts About Folic Acid Language: English Español (Spanish) Share Compartir CDC urges women to ... Blood Disorders & Disabilities Information For... Media Policy Makers Language: English Español (Spanish) File Formats Help: How do I ...

346

(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

347

Lead-acid cell  

Microsoft Academic Search

The specification describes a post seal arrangement for a lead-acid battery. The seal is a resilient bellows which permits relative movement between the cell receptacle and the grids to which the post is attached.

L. D. Babusci; B. A. Cretella; D. O. Feder; D. E. Koontz

1970-01-01

348

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

349

Domoic Acid Fact Sheet  

NSDL National Science Digital Library

This online fact sheet illustrates the transfer of domoic acid through the food web. Domoic acid is a nerve toxin produced by a naturally occurring Harmful Algal Bloom (HAB) usually (but not always) of the genus Pseudonitzchia. The sheet explains what to do if you find a sick or dead animal and includes contact information for injured/sick/entangled animal rescue networks in California.

Sanctuary, Channel I.

350

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.

351

Effects of acid precipitation  

Microsoft Academic Search

Acid precipitation, including dry deposition, is recognized as coming from pollution-caused strong acid precursors that result from the burning of fossil fuels. Recent studies suggest that ecosystems susceptible to acidification occur over the entire length of the Appalachian Mountains and certain other regions of the eastern U.S. This paper reviews a short-term assessment by the EPA to survey the extent

Norman R. Glass; Dean E. Arnold; James N. Galloway; George R. Hendrey; Jeffrey J. Lee; W. W. McFee; Stephen A. Norton; Charles F. Powers; Danny L. Rambo; Carl L. Schofield

1982-01-01

352

Discovery of essential fatty acids.  

PubMed

Dietary fat was recognized as a good source of energy and fat-soluble vitamins by the first part of the 20th century, but fatty acids were not considered to be essential nutrients because they could be synthesized from dietary carbohydrate. This well-established view was challenged in 1929 by George and Mildred Burr who reported that dietary fatty acid was required to prevent a deficiency disease that occurred in rats fed a fat-free diet. They concluded that fatty acids were essential nutrients and showed that linoleic acid prevented the disease and is an essential fatty acid. The Burrs surmised that other unsaturated fatty acids were essential and subsequently demonstrated that linolenic acid, the omega-3 fatty acid analog of linoleic acid, is also an essential fatty acid. The discovery of essential fatty acids was a paradigm-changing finding, and it is now considered to be one of the landmark discoveries in lipid research. PMID:25339684

Spector, Arthur A; Kim, Hee-Yong

2015-01-01

353

Acidification and Acid Rain  

NASA Astrophysics Data System (ADS)

Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw tremendous progress in the documentation of the chemistry of the atmosphere, precipitation, and the systems impacted by acid atmospheric deposition. Chronic acidification of ecosystems results in chemical changes to soil and to surface waters and groundwater as a result of reduction of base cation supply or an increase in acid (H+) supply, or both. The most fundamental changes during chronic acidification are an increase in exchangeable H+ or Al3+ (aluminum) in soils, an increase in H+ activity (˜concentration) in water in contact with soil, and a decrease in alkalinity in waters draining watersheds. Water draining from the soil is acidified and has a lower pH (=-log [H+]). As systems acidify, their biotic community changes.Acidic surface waters occur in many parts of the world as a consequence of natural processes and also due to atmospheric deposition of strong acid (e.g., Canada, Jeffries et al. (1986); the United Kingdom, Evans and Monteith (2001); Sweden, Swedish Environmental Protection Board (1986); Finland, Forsius et al. (1990); Norway, Henriksen et al. (1988a); and the United States (USA), Brakke et al. (1988)). Concern over acidification in the temperate regions of the northern hemisphere has been driven by the potential for accelerating natural acidification by pollution of the atmosphere with acidic or acidifying compounds. Atmospheric pollution ( Figure 1) has resulted in an increased flux of acid to and through ecosystems. Depending on the ability of an ecosystem to neutralize the increased flux of acidity, acidification may increase only imperceptibly or be accelerated at a rate that endangers the existing biota. Concerns about acid (or acidic) rain in its modern sense were publicized by the Swedish soil scientist Svante Odén (1968). He argued, initially in the Swedish press, that long-term increases in the atmospheric deposition of acid could lower the pH of surface waters, cause a decline in fish stocks, deplete soils of nutrients, and accelerate damage to materials. By the 1970s, acidification of surface waters was reported in many countries in Europe as well as in North America. The late twentieth-century rush to understand the impact of acid rain was driven by: (i) reports of damaged or threatened freshwater fisheries and (ii) damaged forests. Perhaps the earliest linkage between acidic surface water and damage to fish was made by Dahl (1921) in southern Norway. There, spring runoff was sufficiently acidic to kill trout. It was not until the 1970s that a strong link was established between depressed pH, mobilization of aluminum from soil, and fish status ( Schofield and Trojnar,1980). The relationship between acidification of soils and forest health started with hypotheses in the 1960s and has slowly developed. Acid rain enhances the availability of some nutrients (e.g., nitrogen), and may either enhance or diminish the availability of others (e.g., calcium, magnesium, potassium, and phosphorus). Damage to anthropogenic structures, human health, and visibility have also raised concerns. The history of these early developments was summarized by Cowling (1982). Since the 1970s, sulfur and nitrogen emissions to the atmosphere have been reduced by 50-85% and 0-30%, respectively, both in North America and Europe. The emission reductions have occurred as a consequence of knowledge gained and economic factors. While recovery of water quality is underway in some areas, problems of acidification persist, and are now complicated by the effects of climate change ( Schindler, 1997).

Norton, S. A.; Veselã½, J.

2003-12-01

354

Acid Rain, pH & Acidity: A Common Misinterpretation.  

ERIC Educational Resources Information Center

Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

Clark, David B.; Thompson, Ronald E.

1989-01-01

355

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

356

Selective adsorption and chiral amplification of amino acids in vermiculite clay-implications for the origin of biochirality  

NASA Astrophysics Data System (ADS)

Smectite clays are hydrated layer silicates that, like micas, occur naturally in abundance. Importantly, they have readily modifiable interlayer spaces that provide excellent sites for nanochemistry. Vermiculite is one such smectite clay and in the presence of small chain-length alkyl-NH3Cl ions, forms sensitive, 1-D ordered model clay systems with expandable nano-pore inter-layer regions. These inter-layers readily adsorb organic molecules. N-propyl NH3Cl vermiculite clay gels were used to determine the adsorption of alanine, lysine and histidine by chiral HPLC. The results show that during reaction with fresh vermiculite interlayers, significant chiral enrichment of either L- and D-enantiomers occurs depending on the amino acid. Chiral enrichment of the supernatant solutions is up to about 1% per pass. In contrast, addition to clay interlayers already reacted with amino acid solutions resulted in little or no change in D/L ratio during the time of the experiment. Adsorption of small amounts of amphiphilic organic molecules in clay inter-layers is known to produce Layer-by-Layer or Langmuir-Blodgett films. Moreover atomistic simulations show that self-organization of organic species in clay interlayers is important. These non-centrosymmetric, chirally active nanofilms may cause clays to act subsequently as chiral amplifiers, concentrating organic material from dilute solution and having different adsorption energetics for D- and L-enantiomers. The additional role of clays in RNA oligimerization already postulated by Ferris and others, together with the need for the organization of amphiphilic molecules and lipids noted by Szostak and others, suggests that such chiral separation by clays in lagoonal environments at normal biological temperatures might also have played a significant role in the origin of biochirality.

Fraser, Donald G.; Fitz, Daniel; Jakschitz, T.; Rode, Bernd M.

357

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

358

XYLARIC ACID, DARABINARIC ACID (D-LYXARIC ACID), L-ARABINARIC ACID (L-LYXARIC ACID), AND RIBARIC ACID-1,4-LACTONE; SYNTHESIS AND ISOLATION SYNTHESIS OF POLYHYDROXYPOLYAMIDES THEREFROM.  

E-print Network

??This dissertation describes the nitric acid oxidation of the pentoses D-xylose, L-arabinose, D-arabinose, and D-ribose to produce xylaric acid, L-arabinaric acid (L-lyxaric acid), D-arabinaric acid… (more)

Hinton, Michael Raymond

2009-01-01

359

Molecular Structure of Malonic acid  

NSDL National Science Digital Library

Propanedioic acid is a dibasic carboxylic acid that was first synthesized by oxidizing malic acid in 1858 by a scientist named Dessaigne. Naturally, propandioic acid is found in apples. This chemical is relatively unstable and has few uses, but its ester derivative, diethyl malonate, is used to synthesize useful compounds such as barbiturates, flavors, fragrances, and vitamins (B1 and B6).

2002-10-10

360

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

361

Pelargonic acid weed control parameters  

Technology Transfer Automated Retrieval System (TEKTRAN)

Producers and researchers are interested in pelargonic acid (nonanoic acid) as a broad-spectrum post-emergence or burn-down herbicide. Pelargonic acid is a fatty acid naturally occurring in many plants and animals, and present in many foods we consume. The objective of this research was to determine...

362

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

363

Acidity and taste in kiwifruit  

Microsoft Academic Search

Although total titratable acidity levels in ‘Hayward’ kiwifruit appear quite stable during storage at 0°C under New Zealand conditions it is known that citric acid levels decline but malic acid levels are maintained. By contrast, malic acid levels tend to increase with storage at 4°C. These observations formed the basis of a sensory comparison of fruit stored at 0, 4,

K. Marsh; S. Attanayake; S. Walker; A. Gunson; H. Boldingh; E. MacRae

2004-01-01

364

The biosynthesis of ricinoleic acid  

PubMed Central

1. Ricinoleic acid is shown to be synthesized in the immature castor bean seed only after 3–4 weeks from the time of fertilization. 2. Synthesis occurs both in the isolated embryo and the endosperm. 3. Linoleic acid does not act as precursor of ricinoleic acid in the isolated bean embryo. 4. Oleic acid is shown to be the direct precursor of ricinoleic acid. 5. The reaction does not use molecular oxygen. This suggests that ricinoleic acid is not a precursor of linoleic acid. PMID:14340094

James, A. T.; Hadaway, H. C.; Webb, Joan P. W.

1965-01-01

365

Domoic Acid Epileptic Disease  

PubMed Central

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.

2014-01-01

366

Optical high acidity sensor  

DOEpatents

An apparatus and method for determining acid concentrations in solutions having acid concentrations of from about 0.1 Molar to about 16 Molar is disclosed. The apparatus includes a chamber for interrogation of the sample solution, a fiber optic light source for passing light transversely through the chamber, a fiber optic collector for receiving the collimated light after transmission through the chamber, a coating of an acid resistant polymeric composition upon at least one fiber end or lens, the polymeric composition in contact with the sample solution within the chamber and having a detectable response to acid concentrations within the range of from about 0.1 Molar to about 16 Molar, a measurer for the response of the polymeric composition in contact with the sample solution, and, a comparer of the measured response to predetermined standards whereby the acid molarity of the sample solution within the chamber can be determined. Preferably, a first lens is attached to the end of the fiber optic light source, the first lens adapted to collimate light from the fiber optic light source, and a second lens is attached to the end of the fiber optic collector for focusing the collimated light after transmission through the chamber.

Jorgensen, Betty S. (Jemez Springs, NM); Nekimken, Howard L. (Los Alamos, NM); Carey, W. Patrick (Lynnwood, WA); O'Rourke, Patrick E. (Martinez, GA)

1997-01-01

367

Optical high acidity sensor  

DOEpatents

An apparatus and method for determining acid concentrations in solutions having acid concentrations of from about 0.1 Molar to about 16 Molar is disclosed. The apparatus includes a chamber for interrogation of the sample solution, a fiber optic light source for passing light transversely through the chamber, a fiber optic collector for receiving the collimated light after transmission through the chamber, a coating of an acid resistant polymeric composition upon at least one fiber end or lens, the polymeric composition in contact with the sample solution within the chamber and having a detectable response to acid concentrations within the range of from about 0.1 Molar to about 16 Molar, a measurer for the response of the polymeric composition in contact with the sample solution, and a comparer of the measured response to predetermined standards whereby the acid molarity of the sample solution within the chamber can be determined. Preferably, a first lens is attached to the end of the fiber optic light source, the first lens adapted to collimate light from the fiber optic light source, and a second lens is attached to the end of the fiber optic collector for focusing the collimated light after transmission through the chamber. 10 figs.

Jorgensen, B.S.; Nekimken, H.L.; Carey, W.P.; O`Rourke, P.E.

1997-07-22

368

Science Shorts: Understanding Acid Rain  

NSDL National Science Digital Library

You may have heard acid rain mentioned as an environmental problem. It doesn't mean that a strong chemical is raining from the sky. The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. However, a small change in how acidic precipitation is can have a profound effect. This month's activity will help students understand the effect of acid rain on buildings and statues.

Damonte, Kathleen

2004-11-01

369

Extracellular nucleic acids.  

PubMed

Extracellular nucleic acids are found in different biological fluids in the organism and in the environment: DNA is a ubiquitous component of the organic matter pool in the soil and in all marine and freshwater habitats. Data from recent studies strongly suggest that extracellular DNA and RNA play important biological roles in microbial communities and in higher organisms. DNA is an important component of bacterial biofilms and is involved in horizontal gene transfer. In recent years, the circulating extracellular nucleic acids were shown to be associated with some diseases. Attempts are being made to develop noninvasive methods of early tumor diagnostics based on analysis of circulating DNA and RNA. Recent observations demonstrated the possibility of nucleic acids exchange between eukaryotic cells and extracellular space suggesting their participation in so far unidentified biological processes. PMID:17563084

Vlassov, Valentin V; Laktionov, Pavel P; Rykova, Elena Y

2007-07-01

370

Acid neutralizing capacity, alkalinity, and acid-base status of natural waters containing organic acids  

Microsoft Academic Search

The terms acid neutralizing capacity (ANC) and alkalinity (Alk) are extensively employed in the characterization of natural waters, including soft circumneutral or acidic waters. However, in the presence of organic acids, ANC measurements are inconsistent with many conceptual definitions of ANC or Alk and do not provide an adequate characterization of the acid-base chemistry of water. Knowledge of Gran ANC

Harold F. Hemond

1990-01-01

371

A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid  

SciTech Connect

An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

Arceo, Elena; Ellman, Jonathan; Bergman, Robert

2010-05-03

372

Acid rain in Asia  

NASA Astrophysics Data System (ADS)

Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging perception that the problem in these Western nations is nearing solution. The situation in the developing world, particularly in Asia, is much bleaker. Given the policies of many Asian nations to achieve levels of development comparable with the industrialized world—which necessitate a significant expansion of energy consumption (most derived from indigenous coal reserves)—the potential for the formation of, and damage from, acid deposition in these developing countries is very high. This article delineates and assesses the emissions patterns, meteorology, physical geology, and biological and cultural resources present in various Asian nations. Based on this analysis and the risk factors to acidification, it is concluded that a number of areas in Asia are currently vulnerable to acid rain. These regions include Japan, North and South Korea, southern China, and the mountainous portions of Southeast Asia and southwestern India. Furthermore, with accelerated development (and its attendant increase in energy use and production of emissions of acid deposition precursors) in many nations of Asia, it is likely that other regions will also be affected by acidification in the near future. Based on the results of this overview, it is clear that acid deposition has significant potential to impact the Asian region. However, empirical evidence is urgently needed to confirm this and to provide early warning of increases in the magnitude and spread of acid deposition and its effects throughout this part of the world.

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

1992-07-01

373

Ethylenediaminetetraacetic acid in endodontics  

PubMed Central

Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented. PMID:24966721

Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

2013-01-01

374

Eucomic acid methanol monosolvate  

PubMed Central

In the crystal structure of the title compound [systematic name: 2-hy­droxy-2-(4-hy­droxy­benz­yl)butane­dioic acid methanol monosolvate], C11H12O6·CH3OH, the dihedral angles between the planes of the carboxyl groups and the benzene ring are 51.23?(9) and 87.97?(9)°. Inter­molecular O—H?O hydrogen-bonding inter­actions involving the hy­droxy and carb­oxy­lic acid groups and the methanol solvent mol­ecule give a three-dimensional structure. PMID:22091200

Li, Guo-Qiang; Li, Yao-Lan; Wang, Guo-Cai; Liang, Zhi-Hong; Jiang, Ren-Wang

2011-01-01

375

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

376

Enantiomeric separation of amino acids and nonprotein amino acids using a particle-loaded  

E-print Network

Enantiomeric separation of amino acids and nonprotein amino acids using a particle acids and three nonprotein amino acids are derivatized with the fluorogenic reagent 4-fluoro-7-nitro-2 liquid chromatography (HPLC). Keywords: Amino acid / Nonprotein amino acid / Capillary

Zare, Richard N.

377

40 CFR 721.3620 - Fatty acid amine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2011 CFR

...acid amine condensate, polycarboxylic acid salts. 721.3620 Section 721.3620 ...acid amine condensate, polycarboxylic acid salts. (a) Chemical substance and significant...acid amine condensate, polycarboxylic acid salts. (PMN P-92-445) is subject...

2011-07-01

378

40 CFR 721.3620 - Fatty acid amine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2013 CFR

...acid amine condensate, polycarboxylic acid salts. 721.3620 Section 721.3620 ...acid amine condensate, polycarboxylic acid salts. (a) Chemical substance and significant...acid amine condensate, polycarboxylic acid salts. (PMN P-92-445) is subject...

2013-07-01

379

40 CFR 721.3620 - Fatty acid amine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2010 CFR

...acid amine condensate, polycarboxylic acid salts. 721.3620 Section 721.3620 ...acid amine condensate, polycarboxylic acid salts. (a) Chemical substance and significant...acid amine condensate, polycarboxylic acid salts. (PMN P-92-445) is subject...

2010-07-01

380

40 CFR 721.3620 - Fatty acid amine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2012 CFR

...acid amine condensate, polycarboxylic acid salts. 721.3620 Section 721.3620 ...acid amine condensate, polycarboxylic acid salts. (a) Chemical substance and significant...acid amine condensate, polycarboxylic acid salts. (PMN P-92-445) is subject...

2012-07-01

381

Design, synthesis and evaluation of caffeic acid phenethyl ester-based inhibitors targeting a selectivity pocket in the active site of human aldo-keto reductase 1B10.  

PubMed

Inhibitors of a human aldo-keto reductase, AKR1B10, are regarded as promising therapeutics for the treatment of cancer, but those with both high potency and selectivity compared to the structurally similar aldose reductase (AKR1B1) have not been reported. In this study, we have found that, among honeybee propolis products, caffeic acid phenethyl ester (CAPE) inhibited AKR1B10 (IC(50) = 80 nM) with 7-fold selectivity over AKR1B1. Based on a model of docked CAPE in AKR1B10, its derivatives were designed, synthesized and evaluated for inhibitory potency. Among them, 3-(4-hydroxy-2-methoxyphenyl)acrylic acid 3-(3-hydroxyphenyl)propyl ester (10c) was the most potent competitive inhibitor (K(i) = 2.6 nM) with 790-fold selectivity for AKR1B10 over AKR1B1. Molecular docking of 10c and site-directed mutagenesis of AKR1B10 residues suggested that the interactions between the 2-methoxy and 3-hydroxy groups of 10c and the enzyme's Val301 and Gln114, respectively, are important for the inhibitor's selectivity. Additionally, the sub-?M concentration of 10c significantly suppressed the farnesal metabolism and cellular proliferation in AKR1B10-overexpressing cells. PMID:22236472

Soda, Midori; Hu, Dawei; Endo, Satoshi; Takemura, Mayuko; Li, Jie; Wada, Ryogo; Ifuku, Syohei; Zhao, Hai-Tao; El-Kabbani, Ossama; Ohta, Shozo; Yamamura, Keiko; Toyooka, Naoki; Hara, Akira; Matsunaga, Toshiyuki

2012-02-01

382

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

383

Bile acid coenzyme A: amino acid N-acyltransferase in the amino acid conjugation of bile acids.  

PubMed

Bile acids are converted to their glycine and taurine N-acyl amidates by enzymes in the liver in a two-step process. This increases their aqueous solubility, particularly in the acidic environment of the upper part of the small intestine. Bile acid coenzyme A (CoA) thioesters synthesized by bile acid CoA ligase (see Shonsey et al., 2005) are substrates of bile acid CoA:amino acid N-acyltransferases (BAT) in the formation of bile acid N-acyl amidates. This chapter describes the methods used to purify BAT from human liver, to isolate and clone cDNAs encoding BAT from human, mouse, and rat liver cDNA libraries, the expression of BAT, the assays used to measure BAT activity, and the chemical syntheses of bile acid N-acylamidates. In addition, an enzyme that catalyzes further metabolism of glycine-conjugated bile acids is described. PMID:16399361

Shonsey, Erin M; Sfakianos, Mindan; Johnson, Michelle; He, Dongning; Falany, Charles N; Falany, Josie; Merkler, David J; Barnes, Stephen

2005-01-01

384

Reduction of glycyrrhizic acid  

Microsoft Academic Search

The reduction of glycyrrhizic acid by NaBH4 and LiAlH4 was studied. The conditions for the selective reduction of the COOH groups of the carbohydrate chain and the C(11)=0 group\\u000a of aglycon were found.

L. A. Baltina; N. G. Serdyuk; E. V. Vasil’eva; G. A. Tolstikov

1997-01-01

385

Acidification and Acid Rain  

Microsoft Academic Search

Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw

S. A. Norton

2003-01-01

386

Basically Acidic Ink  

NSDL National Science Digital Library

Students hypothesize whether vinegar and ammonia-based glass cleaner are acids or bases. They create designs on index cards using these substances as invisible inks. After the index cards have dried, they apply red cabbage juice as an indicator to reveal the designs.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

387

The Acid Rain Debate.  

ERIC Educational Resources Information Center

Details an activity designed to motivate students by incorporating science-related issues into a classroom debate. Includes "The Acid Rain Bill" and "Position Guides" for student roles as committee members, consumers, governors, industry owners, tourism professionals, senators, and debate directors. (DKM)

Oates-Bockenstedt, Catherine

1997-01-01

388

Acid Rain Classroom Projects.  

ERIC Educational Resources Information Center

Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

Demchik, Michael J.

2000-01-01

389

The Acid Rain Game.  

ERIC Educational Resources Information Center

Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

Rakow, Steven J.; Glenn, Allen

1982-01-01

390

The Acid Rain Debate.  

ERIC Educational Resources Information Center

Describes an activity which provides opportunities for role-playing as industrialists, ecologists, and government officials. The activity involves forming an international commission on acid rain, taking testimony, and, based on the testimony, making recommendations to governments on specific ways to solve the problem. Includes suggestions for…

Bybee, Rodger; And Others

1984-01-01

391

Acid Rain Investigations.  

ERIC Educational Resources Information Center

Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

Hugo, John C.

1992-01-01

392

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 ...

393

Spermatotoxicity of dichloroacetic acid  

EPA Science Inventory

The testicular toxicity of dichloroacetic acid (DCA), a disinfection byproduct of drinking water, was evaluated in adult male rats given both single and multiple (up to 14 d) oral doses. Delayed spermiation and altered resorption of residual bodies were observed in rats given sin...

394

Valproic Acid: second generation.  

PubMed

The manuscript focuses on structure-activity relationship studies of CNS-active compounds derived from valproic acid (VPA) that have the potential to become second-generation VPA drugs. Valproic acid is one of the four most widely prescribed antiepileptic drugs (AEDs) and is effective (and regularly approved) in migraine prophylaxis and in the treatment of bipolar disorders. Valproic acid is also currently undergoing clinical trials in cancer patients. Valproic acid is the least potent of the established AEDs and its use is limited by two rare but potentially life-threatening side effects, teratogenicity and hepatotoxicity. Because AEDs treat the symptoms (seizure) and not the cause of epilepsy, epileptic patients need to take AEDs for a long period of time. Consequently, there is a substantial need to develop better and safer AEDs. To become a successful second-generation VPA, the new drug should possess the following characteristics: broad-spectrum antiepileptic activity, better potency than VPA, lack of teratogenicity and hepatotoxicity, and a favorable pharmacokinetic profile compared with VPA including a low potential for drug interactions. PMID:17199028

Bialer, Meir; Yagen, Boris

2007-01-01

395

Brain amino acid sensing.  

PubMed

The 20 different amino acids, in blood as well as in the brain, are strictly maintained at the same levels throughout the day, regardless of food intake. Gastric vagal afferents only respond to free glutamate and sugars, providing recognition of food intake and initiating digestion. Metabolic control of amino acid homeostasis and diet-induced thermogenesis is triggered by this glutamate signalling in the stomach through the gut-brain axis. Rats chronically fed high-sugar and high-fat diets do not develop obesity when a 1% (w/v) monosodium glutamate (MSG) solution is available in a choice paradigm. Deficiency of the essential amino acid lysine (Lys) induced a plasticity in rats in response to Lys. This result shows how the body is able to identify deficient nutrients to maintain homeostasis. This plastic effect is induced by activin A activity in the brain, particularly in certain neurons in the lateral hypothalamic area (LHA) which is the centre for amino acid homeostasis and appetite. These neurons respond to glutamate signalling in the oral cavity by which umami taste is perceived. They play a quantitative role in regulating ingestion of deficient nutrients, thereby leading to a healthier life. After recovery from malnutrition, rats prefer MSG solutions, which serve as biomarkers for protein nutrition. PMID:25200295

Tsurugizawa, T; Uneyama, H; Torii, K

2014-09-01

396

Effects of Acid Rain  

NSDL National Science Digital Library

This portal provides links to information on the potential damage caused to the environment by acid rain. An introductory paragraph briefly describes the damage to lakes and streams, building materials, and monuments. Each link access additional information on these topics: surface waters and aquatic animals, forests, automotive coatings, soluble building materials such as marble or limestone, atmospheric haze, and human health effects.

397

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

398

Acid rain bibliography  

SciTech Connect

This bibliography identifies 900 citations on various aspects of Acid Rain, covering published bibliographies, books, reports, conference and symposium proceedings, audio visual materials, pamphlets and newsletters. It includes five sections: citations index (complete record of author, title, source, order number); KWIC index; title index; author index; and source index. 900 references.

Sayers, C.S.

1983-09-01

399

Effects of acid precipitation  

Microsoft Academic Search

A growing body of evidence suggests that acid rain is responsible for substantial adverse effects on the public welfare. Such effects include: the acidification of lakes and rivers, with resultant damage to fish and other components of aquatic ecosystems; acidification and demineralization of soils; and possible reductions in crop and forest productivity. Affected areas include Canada and the northeastern US.

Norman R. Glass; Gary E. Glass; Peter J. Rennie

1979-01-01

400

Solubility and aggregation behavior of dendronized poly(p-benzamide)s.  

PubMed

A series of Fréchet dendronized poly(p-benzamide)s have been synthesized. To attach the dendron-functionalities to the poly(p-benzamide) backbone, a propargyl side chain was introduced to p-aminobenzoic acid. Then, copper catalyzed azide-alkyne cycloaddition was used to click a first generation (G(1)), respectively, a second generation (G(2)) Fréchet-dendron azide onto the amino acid monomer. The resulting amino acids were polymerized using triphenylphosphite to obtain a poorly organo-soluble G(1)-dendronized polymer and a non-aggregating G(2)-dendronized polymer showing good organo-solubility. Furthermore, a strictly alternating non-aggregating G(1)-TEG-dendronized polymer with good organo-solubility was synthesized. The aggregation behavior of these polymers was investigated by dynamic light scattering. PMID:21433147

Storz, Christof; Schulze, Maren; Kilbinger, Andreas F M

2011-01-17

401

Acid diffusion through polyaniline membranes  

SciTech Connect

Polyaniline membranes in the undoped (base) and doped (acid) forms are studied for their utility as pervaporation membranes. The separation of water from mixtures of propionic acid, acetic acid and formic acid have been demonstrated from various feed compositions. Doped polyaniline displays an enhanced selectivity of water over these organic acids as compared with undoped polyaniline. For as-cast polyaniline membranes a diffusion coefficient (D) on the order of 10{sup -9} cm{sup 2}/sec has been determined for the flux of protons through the membranes using hydrochloric acid.

Su, T.M.; Huang, S.C.; Conklin, J.A. [Univ. of California, Los Angeles, CA (United States)] [and others

1995-12-01

402

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

403

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

404

Fatty acid selectivity of lipases: Erucic acid from rapeseed oil  

Microsoft Academic Search

The fatty acid selectivity of several commercial lipases was evaluated in the hydrolysis of high-erucic acid rapeseed oil\\u000a (HEARO). The lipase ofPseudomonas cepacia catalyzed virtually complete hydrolysis of the oil (94–97%), while that ofGeotrichum candidum discriminated strongly against erucic acid, especially in esterification. A two-step process is suggested for obtaining a\\u000a highly enriched erucic acid in which theG. candidum lipase

Philip E. Sonnet; Thomas A. Foglia; Stephen H. Feairheller

1993-01-01

405

Carboxylic Acid Unknowns and Titration 90 CARBOXYLIC ACID UNKNOWN  

E-print Network

Point/Boiling Point If your carboxylic acid is a solid, take its melting point. If it is a liquid, take its micro- boiling point. C. Titration/Neutralization EquivalenceMolecular Weight Determination WeighCarboxylic Acid Unknowns and Titration 90 CARBOXYLIC ACID UNKNOWN A. Solubility Tests: Water, Na

Jasperse, Craig P.

406

Oxalic acid excretion after intravenous ascorbic acid administration  

Microsoft Academic Search

Ascorbic acid is frequently administered intravenously by alternative health practitioners and, occasionally, by mainstream physicians. Intravenous administration can greatly increase the amount of ascorbic acid that reaches the circulation, potentially increasing the risk of oxalate crystallization in the urinary space. To investigate this possibility, we developed gas chromatography mass spectrometry methodology and sampling and storage procedures for oxalic acid analysis

Line Robitaille; Orval A. Mamer; Wilson H. Miller Jr.; Mark Levine; Sarit Assouline; David Melnychuk; Caroline Rousseau; L. John Hoffer

2009-01-01

407

College Chemistry Students' Mental Models of Acids and Acid Strength  

ERIC Educational Resources Information Center

The central goal of this study was to characterize the mental models of acids and acid strength expressed by advanced college chemistry students when engaged in prediction, explanation, and justification tasks that asked them to rank chemical compounds based on their relative acid strength. For that purpose we completed a qualitative research…

McClary, LaKeisha; Talanquer, Vicente

2011-01-01

408

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

409

SPECTROFLUOROMETRIC ASSAY FOR HYPOHALITE AND PEROXYACETIC ACID USING KOJIC ACID  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hypochlorite reacted with kojic acid to form an intensely fluorescent product with excitation and emission wavelengths at 395 and 495 nm, respectively. Hypobromite, generated by reaction of hypochlorite or peroxyacetic acid with NaBr, also reacted with kojic acid to generate an identical fluorescen...

410

An amino acid transporter involved in gastric acid secretion  

Microsoft Academic Search

Gastric acid secretion is regulated by a variety of stimuli, in particular histamine and acetyl choline. In addition, dietary factors such as the acute intake of a protein-rich diet and the subsequent increase in serum amino acids can stimulate gastric acid secretion only through partially characterized pathways. Recently, we described in mouse stomach parietal cells the expression of the system

Philipp Kirchhoff; Mital H. Dave; Christine Remy; Ortrud Kosiek; Stephanie M. Busque; Matthias Dufner; John P. Geibel; Francois Verrey; Carsten A. Wagner

2006-01-01

411

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

412

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

413

Asphaltene damage in matrix acidizing  

E-print Network

asphaltene deposition in the reservoir. Frequently, the cause of destabilization is the acid stimulation of the reservoir. Published work in the field of matrix acidizing has been limited to cores saturated with brine. Research in two phase systems has been...

Hinojosa, Roberto Antonio

1996-01-01

414

The Composition of Arylstibonic Acids.  

E-print Network

??This thesis describes a detailed ESI-MS investigation into the arylstibonic acids, organo-antimony-containing compounds that are currently of interest as anticancer reagents. Four arylstibonic acids, of… (more)

Wright, Cody Elvin

2010-01-01

415

Folic Acid: Data and Statistics  

MedlinePLUS

... CDC.gov . Folic Acid Share Compartir Data and Statistics On this Page In the United States Hispanic/ ... Questions & Answers Cereals with Folic Acid Data and Statistics Research Birth Defects COUNT Articles & Key Findings Recommendations ...

416

Omega-3-acid Ethyl Esters  

MedlinePLUS

Omega-3-acid ethyl esters are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the ... triglycerides (a fat-like substance) in your blood. Omega-3-acid ethyl esters are in a class of ...

417

Novel renal amino acid transporters.  

PubMed

Reabsorption of amino acids, similar to that of glucose, is a major task of the proximal kidney tubule. Various amino acids are actively transported across the luminal brush border membrane into proximal tubule epithelial cells, most of which by cotransport. An important player is the newly identified cotransporter (symporter) B0AT1 (SLC6A19), which imports a broad range of neutral amino acids together with Na+ across the luminal membrane and which is defective in Hartnup disorder. In contrast, cationic amino acids and cystine are taken up in exchange for recycled neutral amino acids by the heterodimeric cystinuria transporter. The basolateral release of some neutral amino acids into the extracellular space is mediated by unidirectional efflux transporters, analogous to GLUT2, that have not yet been definitively identified. Additionally, cationic amino acids and some other neutral amino acids leave the cell basolaterally via heterodimeric obligatory exchangers. PMID:15709970

Verrey, François; Ristic, Zorica; Romeo, Elisa; Ramadan, Tamara; Makrides, Victoria; Dave, Mital H; Wagner, Carsten A; Camargo, Simone M R

2005-01-01

418

An amino acid transporter involved in gastric acid secretion.  

PubMed

Gastric acid secretion is regulated by a variety of stimuli, in particular histamine and acetyl choline. In addition, dietary factors such as the acute intake of a protein-rich diet and the subsequent increase in serum amino acids can stimulate gastric acid secretion only through partially characterized pathways. Recently, we described in mouse stomach parietal cells the expression of the system L heteromeric amino acid transporter comprised of the LAT2-4F2hc dimer. Here we address the potential role of the system L amino acid transporter in gastric acid secretion by parietal cells in freshly isolated rat gastric glands. RT-PCR, western blotting and immunohistochemistry confirmed the expression of 4F2-LAT2 amino acid transporters in rat parietal cells. In addition, mRNA was detected for the B(0)AT1, ASCT2, and ATB(0+) amino acid transporters. Intracellular pH measurements in parietal cells showed histamine-induced and omeprazole-sensitive H+-extrusion which was enhanced by about 50% in the presence of glutamine or cysteine (1 mM), two substrates of system L amino acid transporters. BCH, a non-metabolizable substrate and a competitive inhibitor of system L amino acid transport, abolished the stimulation of acid secretion by glutamine or cysteine suggesting that this stimulation required the uptake of amino acids by system L. In the absence of histamine glutamine also stimulated H+-extrusion, whereas glutamate did not. Also, phenylalanine was effective in stimulating H+/K+-ATPase activity. Glutamine did not increase intracellular Ca2+ levels indicating that it did not act via the recently described amino acid modulated Ca2+-sensing receptor. These data suggest a novel role for heterodimeric amino acid transporters and may elucidate a pathway by which protein-rich diets stimulate gastric acid secretion. PMID:16308696

Kirchhoff, Philipp; Dave, Mital H; Remy, Christine; Kosiek, Ortrud; Busque, Stephanie M; Dufner, Matthias; Geibel, John P; Verrey, Francois; Wagner, Carsten A

2006-03-01

419

Molecular Structure of Octanoic acid  

NSDL National Science Digital Library

Caprylic acid is a colorless oil manufactured from 1-heptene or 1-octanol. Octanoic acid has an unpleasant rancid taste. When converted from the carboxlic acid to an ester, it has a pleasant taste. In addition, esters of caprylic acid are used in the preparation of dyes, perfumes, and food preservatives. This compound has also been found to have antifungal activity and is used to treat yeast infections.

2002-10-11

420

Fatty acid signaling in Arabidopsis  

Microsoft Academic Search

.   Many organisms use fatty acid derivatives as biological regulators. In plants, for example, fatty acid-derived signals have\\u000a established roles in the regulation of developmental and defense gene expression. Growing numbers of these compounds, mostly\\u000a derived from fatty acid hydroperoxides, are being characterized. The model plant Arabidopsis thaliana is serving a vital role in the discovery of fatty acid-derived signal

Edward E. Farmer; Hans Weber; Sabine Vollenweider

1998-01-01

421

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.

422

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

423

Molecular Structure of Trimesic acid  

NSDL National Science Digital Library

Trimesic Acid is made up of a benzene ring with three carboxylic groups at the 1, 3, and 5 positions, and it can be synthesized from the oxidation of 1,3,5-trimethyl benzene. The acid is an important building block in crystal engineering which is used to form honeycomb structures, but it has the ability to form diverse supramolecular structures. Also, trimesic acid salt and the free trimesic acid are useful as a plasticizer.

2003-05-08

424

XYLARIC ACID, D-ARABINARIC ACID (D-LYXARIC ACID), L-ARABINARIC ACID (L-LYXARIC ACID), AND RIBARIC ACID-1,4-LACTONE; SYNTHESIS AND ISOLATION - SYNTHESIS OF POLYHYDROXYPOLYAMIDES THEREFROM.  

E-print Network

?? This dissertation describes the nitric acid oxidation of the pentoses D-xylose, L-arabinose, D-arabinose, and D-ribose to produce xylaric acid, L-arabinaric acid (L-lyxaric acid), D-arabinaric… (more)

Hinton, Michael Raymond

2009-01-01

425

Weak Acid Equilibrium  

NSDL National Science Digital Library

Students are asked to calculate the pH of a weak acid aqueous solution. The problems involve a series of generic acids with assigned equilibrium constants (Ka) and total concentrations (Ct). Initially, students are required to hand calculate all problems by algebraic manipulation of the mathematical relationships of the system. The solution is a cubic equation. Through a series of assumptions, the solution is simplified. The assumptions are based on the chemistry of the system given the Ka and Ct for the problem. The problems are then graphically solved. Ultimately, the students develop an Excel worksheet to solve the problems and a Bjerrum plot to display the speciation as a function of pH.

Stapleton, Michael

426

Industrial ecotoxicology "acid rain".  

PubMed

The acid rain phenomenon was studied in the province of Cordoba, Argentina. This study, based on a previously outlined framework, determined the anthropogenic origin of the low pH due to the presence of industrial hydrochloric acid wastage. This industrial ecotoxicological phenomenon seriously affected the forest wealth, causing a great defoliation of trees and shrubs, with a lower effect on crops. A survey on its effects on human beings has not been carried out, but considering the corrosion caused to different metals and its denouncing biocide effect on plants and animals, we should expect to find some kind of harm to the health of the workers involved or others engaged in farming, and even to those who are far away from the polluting agent. PMID:3758667

Astolfi, E; Gotelli, C; Higa, J

1986-01-01

427

Spermatotoxicity of dichloroacetic acid  

Microsoft Academic Search

The testicular toxicity of dichloroacetic acid (DCA), a disinfection byproduct of drinking water, was evaluated in adult male rats given both single and multiple (up to 14 d) oral doses. Delayed spermiation and altered resorption of residual bodies were observed in rats given single doses of 1500 and 3000 mg\\/kg; these effects persisted to varying degrees on post-treatment days 2,14,

Ralph E. Linder; Gary R. Klinefelter; Lillian F. Strader; Juan D. Suarez; Naomi L. Roberts

1997-01-01

428

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

429

Lipoic Acid Synthase (LASY)  

PubMed Central

OBJECTIVE—Lipoic acid synthase (LASY) is the enzyme that is involved in the endogenous synthesis of lipoic acid, a potent mitochondrial antioxidant. The aim of this study was to study the role of LASY in type 2 diabetes. RESEARCH DESIGN AND METHODS—We studied expression of LASY in animal models of type 2 diabetes. We also looked at regulation of LASY in vitro under conditions that exist in diabetes. Additionally, we looked at effects of LASY knockdown on cellular antioxidant status, inflammation, mitochondrial function, and insulin-stimulated glucose uptake. RESULTS—LASY expression is significantly reduced in tissues from animal models of diabetes and obesity compared with age- and sex-matched controls. In vitro, LASY mRNA levels were decreased by the proinflammatory cytokine tumor necrosis factor (TNF)-? and high glucose. Downregulation of the LASY gene by RNA interference (RNAi) reduced endogenous levels of lipoic acid, and the activities of critical components of the antioxidant defense network, increasing oxidative stress. Treatment with exogenous lipoic acid compensated for some of these defects. RNAi-mediated downregulation of LASY induced a significant loss of mitochondrial membrane potential and decreased insulin-stimulated glucose uptake in skeletal muscle cells. In endothelial cells, downregulation of LASY aggravated the inflammatory response that manifested as an increase in both basal and TNF-?–induced expression of the proinflammatory cytokine, monocyte chemoattractant protein-1 (MCP-1). Overexpression of the LASY gene ameliorated the inflammatory response. CONCLUSIONS—Deficiency of LASY results in an overall disturbance in the antioxidant defense network, leading to increased inflammation, insulin resistance, and mitochondrial dysfunction. PMID:19074983

Padmalayam, Indira; Hasham, Sumera; Saxena, Uday; Pillarisetti, Sivaram

2009-01-01

430

Acid Rain Effects  

NSDL National Science Digital Library

Learners conduct a simple experiment to model and explore the harmful effects of acid rain (vinegar) on living (green leaf and eggshell) and non-living (paper clip) objects. Learners observe the effects over a period of days. This activity has links to other activities which can be combined to make a larger lesson. 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

2004-01-01

431

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

432

An Umbrella for Acid Rain.  

ERIC Educational Resources Information Center

The Environmental Protection Agency has awarded several grants to study effects of and possible solutions to the problem of "acid rain"; pollution from atmospheric nitric and sulfuric acids. The research program is administered through North Carolina State University at Raleigh and will focus on biological effects of acid rain. (JMF)

Randal, Judith

1979-01-01

433

Molecular Structure of Carbonic acid  

NSDL National Science Digital Library

The hypothetical acid formed with carbon dioxide and water; it is only in the H2CO3 form when in solution. This acid is found in everyday products, the most prominent of which include carbonated beverages. The conversion of carbonic acid into water and carbon dioxide in sodas is the reason the beverage looses the bubbling.

2002-09-10

434

Pantothenic acid biosynthesis in zymomonas  

DOEpatents

Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V.

2014-07-01

435

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

436

Nucleic Acids Molecular Biology Tools  

E-print Network

Nucleic Acids Proteins Molecular Biology Tools Molecular Biology and Genomics Weigang Qiu Weigang Qiu Molecular Biology and Genomics #12;Nucleic Acids Proteins Molecular Biology Tools Outline 1 Nucleic Acids 2 Proteins 3 Molecular Biology Tools Weigang Qiu Molecular Biology and Genomics #12;Nucleic

Qiu, Weigang

437

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

438

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

439

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

440

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

441

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

NASA Astrophysics Data System (ADS)

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

McCollom, Thomas M.; Seewald, Jeffrey S.

2003-10-01

442

Composition for nucleic acid sequencing  

DOEpatents

The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

Korlach, Jonas (Ithaca, NY); Webb, Watt W. (Ithaca, NY); Levene, Michael (Ithaca, NY); Turner, Stephen (Ithaca, NY); Craighead, Harold G. (Ithaca, NY); Foquet, Mathieu (Ithaca, NY)

2008-08-26

443

Vibrational structure of the polyunsaturated fatty acids eicosapentaenoic acid and arachidonic acid studied by infrared spectroscopy  

Microsoft Academic Search

The spectroscopic discrimination of the two structurally similar polyunsaturated C20 fatty acids (PUFAs) 5,8,11,14,17-eicosapentaenoic acid and 5,8,11,14-eicosatetraenoic acid (arachidonic acid) is shown. For this purpose their vibrational structures are studied by means of attenuated total reflection (ATR) Fourier-transform infrared (FT-IR) spectroscopy. The fingerprint regions of the recorded spectra are found to be almost identical, while the C–H stretching mode regions

Johannes Kiefer; Kristina Noack; Juergen Bartelmess; Christian Walter; Heike Dörnenburg; Alfred Leipertz

2010-01-01

444

Molecular Structure of Adipic acid  

NSDL National Science Digital Library

Adipic acid is odorless and colorless white crystals or powder with a sour taste. Adipic acid is used primarily in the manufacture of nylon-6,6 polyamide and polyester polyols for polyurethane systems. It is also used for raw materials in pharmaceuticals, perfume fixatives, acidulants, leavening and buffering agents in non-alcoholic beverages, gelatins and puddings. In addition, adipic acid is used in manufacturing plasticizers and lubricants components. It is slightly soluble in water and soluble in alcohol and acetone. Adipic acid can be prepared from acetylene and acetic acid in the presence of tert-butyl peroxide. It has been manufactured from either cyclohexane or phenol.

2004-11-09

445

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

446

Acid Rain Experiments: Soil Buffering  

NSDL National Science Digital Library

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

447

Molecular Structure of Benzoic acid  

NSDL National Science Digital Library

Benzoic acid is a medium-strong acid found in human foods such as berries, and is used as a plasticizer, insecticide, fungicide, an antifungal agent and in the manufacture of pharmaceuticals. It is more hydrophobic, water fearing, in comparison with other carboxylic acids and therefore can be extracted easily from all types of solvents. This acid is slightly soluble in water and has a melting point of 122 degrees Celsius. Benzoic acid is industrially manufactured from toluene, benzotrichloride and phthalic anhydride. It is purified by the process of sublimation, and the extremely pure form is used as a titrimetric and calorimetric standard in analytical chemistry.

2003-05-08

448

Invasive cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

1999-01-01

449

Invasive cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

2002-01-01

450

The effects of nitric acid and silane surface treatments on carbon fibers and carbon/vinyl ester composites before and after seawater exposure  

NASA Astrophysics Data System (ADS)

This research focuses on carbon fiber treatment by nitric acid and 3-(trimethoxysilyl)propyl methacrylate silane, and how this affects carbon/vinyl ester composites. These composites offer great benefits, but it is difficult to bond the fiber and matrix together, and without a strong interfacial bond, composites fall short of their potential. Silanes work well with glass fiber, but do not bond directly to carbon fiber because its surface is not reactive to liquid silanes. Oxidizing surface treatments are often prescribed for improved wetting and bonding to carbon, but good results are not always achieved. Furthermore, there is the unanswered question of environmental durability. This research aimed to form a better understanding of oxidizing carbon fiber treatments, determine if silanes can be bonded to oxidized surfaces, and how these treatments affect composite strength and durability before and after seawater exposure. Nitric acid treatments on carbon fibers were found to improve their tensile strength to a constant level by smoothing surface defects and chemically modifying their surfaces by increasing carbonyl and carboxylic acid concentrations. Increasing these surface group concentrations raises fiber polar energy and causes them to cohere. This impedes wetting, resulting in poor quality, high void content composites, even though there appeared to be improved adhesion between the fibers and matrix. Silane was found to bond to the oxidized carbon fiber surfaces, as evidenced by changes in both fiber and composite properties. The fibers exhibited low polarity and cohesion, while the composites displayed excellent resin wetting, low void content, and low seawater weight gain and swelling. On the contrary, the oxidized fibers that were not treated with silane exhibited high polarity and fiber cohesion. Their composites displayed poor wetting, high void content, high seawater weight gain, and low swelling. Both fiber treatment types resulted in great improvements in dry transverse tensile strength over the untreated fibers, but the oxidized fiber composites lost strength as the acid treatment time was extended, due to poor wetting. The acid/silane treated composites lost some transverse tensile strength after seawater exposure, but the nitric acid oxidized fiber composites appeared to be more seawater durable.

Langston, Tye A.

451

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

452

Liquid chromatographic determination of nitrilotriacetic acid, ethylenediaminetetraacetic acid, and related aminopolycarboxylic acids using an amperometric detector  

SciTech Connect

An amperometric detector employing a carbon-paste electrode is used to determine aminopolycarboxylic acids, including nitrilotriacetic acid (NTA) to determine aminopolycarboxylic acids, including nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA), after liquid chromatographic separation on a reversed-phase column with an aqueous trichloroacetic acid mobile phase at pH lower than 2. The aminopolycarboxylic acids are directly oxidized at the detector electrode without involving an intermediate species. Glycine, iminodiacetic acid, common amino acids, citric acid, and fulvic acids do not interfere with the determination of NTA and EDTA. The low mobile-phase pH limits interference from metal ions in natural waters. Where such interference occurs, a stronger chelating reagent (e.g. diethylenetriaminepentaacetic acid (DPTA) can be used to suppress it. NTA and EDTA in aqueous samples, including waste water treatment plant influent and effluent, can be determined without prior sample preparation. The minimum detectable amounts are 0.1 ppm for NTA and 0.15 ppm for EDTA with a precision of less than 7% relative standard deviation.

Dai, J.; Helz, G.R.

1988-02-15

453

Gas chromatography of fatty acids.  

PubMed

Lipids in foods contain a wide variety of fatty acids differing in chain length, degree of unsaturation, position and configuration of double bonds and the presence of special functional groups. Modern capillary gas chromatography offers excellent separation of fatty acids. Fused-silica capillary columns with stationary phases of medium polarity and non-polar methylsilicone stationary phases successfully separate most of the natural fatty acids. Special applications, such as the separation of complex cis-trans fatty acid mixtures and cyclic fatty acids, required particular chromatographic conditions, including the use of very long capillary columns or more polar stationary phases. The derivatization methods for the preparation of fatty acid esters also need to be optimized to obtain accurate quantitative results. This paper reviews the derivatization techniques, capillary columns and stationary phases commonly used in the gas chromatography of fatty acids in food. PMID:1494015

Shantha, N C; Napolitano, G E

1992-10-30

454

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

455

Fungal metabolites of sorbic acid.  

PubMed

A number of fungal detoxification reactions of sorbic acid have been reviewed. These include decarboxylation to give trans-1,3-pentadiene, esterification to give ethyl sorbate, reduction to give 4-hexenol and 4-hexenoic acid. It was shown that seven Penicillium species could convert sorbic acid into 1,3-pentadiene whilst P. bilaii, P. fellutanum and P. glabrum did not. However, most Eurotium species were unable to bring about this conversion. Considerable differences in the resistance of two isolates of P. crustosum to sorbic acid were found. An isolate from coconut was more resistant than one isolated from hazelnuts. Both sorbic acid and caproic acid (hexanoic) brought about disorganization of the mitochondrial membranes in P. crustosum. It is suggested that these lipophilic acids inhibit growth by interfering with the electrochemical membrane potential across the mitochondrial membranes. PMID:2253810

Kinderlerer, J L; Hatton, P V

1990-01-01

456

21 CFR 573.480 - Formic acid.  

Code of Federal Regulations, 2013 CFR

...concerning formic acid (85 percent formic acid). (ii) Statements identifying formic acid (85 percent formic acid) as a corrosive and possible severe irritant...Occupational Safety and Health Administration's (OSHA) human safety guidance...

2013-04-01

457

21 CFR 573.480 - Formic acid.  

Code of Federal Regulations, 2012 CFR

...concerning formic acid (85 percent formic acid). (ii) Statements identifying formic acid (85 percent formic acid) as a corrosive and possible severe irritant...Occupational Safety and Health Administration's (OSHA) human safety guidance...

2012-04-01

458

21 CFR 573.480 - Formic acid.  

Code of Federal Regulations, 2014 CFR

...concerning formic acid (85 percent formic acid). (ii) Statements identifying formic acid (85 percent formic acid) as a corrosive and possible severe irritant...Occupational Safety and Health Administration's (OSHA) human safety guidance...

2014-04-01

459

21 CFR 573.480 - Formic acid.  

Code of Federal Regulations, 2011 CFR

...concerning formic acid (85 percent formic acid). (ii) Statements identifying formic acid (85 percent formic acid) as a corrosive and possible severe irritant...Occupational Safety and Health Administration's (OSHA) human safety guidance...

2011-04-01

460

Electrochemical deoxyribonucleic acid biosensor based on the self-assembly film with nanogold decorated on ionic liquid modified carbon paste electrode.  

PubMed

An electrochemical DNA biosensor was fabricated by self-assembling probe single-stranded DNA (ssDNA) with a nanogold decorated on ionic liquid modified carbon paste electrode (IL-CPE). IL-CPE was fabricated using 1-butylpyridinium hexafluorophosphate as the binder and the gold nanoparticles were electrodeposited on the surface of IL-CPE (Au/IL-CPE). Then mercaptoacetic acid was self-assembled on the Au/IL-CPE to obtain a layer of modified film, and the ssDNA probe was further covalently-linked with mercaptoacetic acid by the formation of carboxylate ester with the help of N-(3-dimethylamino-propyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide. The hybridization reaction with the target ssDNA was monitored with methylene blue (MB) as the electrochemical indicator. Under the optimal conditions, differential pulse voltammetric responses of MB was proportional to the specific ssDNA arachis sequences in the concentration range from 1.0×10(-11) to 1.0×10(-6) mol L(-1) with the detection limit as 1.5×10(-12) mol L(-1) (3?). This electrochemical DNA sensor exhibited good stability and selectivity with the discrimination ability of the one-base and three-base mismatched ssDNA sequences. The polymerase chain reaction product of arachis Arabinose operon D gene was successfully detected by the proposed method, which indicated that the electrochemical DNA sensor designed in this paper could be further used for the detection of specific ssDNA sequence. PMID:21907030

Gao, Hongwei; Qi, Xiaowei; Chen, Ying; Sun, Wei

2011-10-17

461

Metabolism of 14 C-labelled oleic acid, erucic acid and nervonic acid in rats  

Microsoft Academic Search

1-14C-Oleic acid, 2-14C-erucic acid and 2-14C-nervonic acid were administered to rats by tail-vein and the distribution of radioactivity in liver lipids was determined\\u000a at intervals from 15 min to 6 hr after injection. High levels of activity were found after short time intervals which were\\u000a mainly associated with triglycerides in the case of oleic acid and with free fatty acids

K. K. Carroll

1966-01-01

462

Mycophenolic Acid in Silage  

PubMed Central

We examined 233 silage samples and found that molds were present in 206 samples with counts between 1 × 103 and 8.9 × 107 (mean, 4.7 × 106) CFU/g. Mycophenolic acid, a metabolite of Penicillium roqueforti, was detected by liquid chromatography-mass spectrometry in 74 (32%) of these samples at levels ranging from 20 to 35,000 (mean, 1,400) ?g/kg. This compound has well-known immunosuppressive properties, so feeding with contaminated silage may promote the development of infectious diseases in livestock. PMID:10919834

Schneweis, Isabell; Meyer, Karsten; Hörmansdorfer, Stefan; Bauer, Johann

2000-01-01

463

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

464

76 FR 61692 - Certain New Chemicals; Receipt and Status Information  

Federal Register 2010, 2011, 2012, 2013, 2014

...Propenoic be polymerized, acid, 3-[ [ 1,1- copolymerized...hydroxymethyl) coatings; propyl] amino]- medical 2-methyl...G) Industrial (G) Amino acid, cleaning carboxyalkyl...G) Industrial (G) Amino acid, cleaning...

2011-10-05

465

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

466

Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells  

Microsoft Academic Search

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

Yao Zhang; Rui-Dong Duan

2009-01-01

467

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

468

40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.  

Code of Federal Regulations, 2010 CFR

...n-Butyric Acid n-Butyric Anhydride *n-Paraffins n-Propyl Acetate n-Propyl Alcohol...Sorbitol Stearic Acid, Calcium Salt (Wax) Tert-Butyl Alcohol 1-Butene... Carbon Tetrachloride *Chlorinated Paraffins, 35-64 PCT, Chlorine...

2010-07-01

469

Cryoprotection from lipoteichoic acid  

NASA Astrophysics Data System (ADS)

Numerous chemical additives lower the freezing point of water, but life at sub-zero temperatures is sustained by a limited number of biological cryoprotectants. Antifreeze proteins in fish, plants, and insects provide protection to a few degrees below freezing. Microbes have been found to survive at even lower temperatures, and with a few exceptions, antifreeze proteins are missing. Survival has been attributed to external factors, such as the high salt concentration of brine veins and adhesion to particulates or ice crystal defects. We have discovered an endogenous cryoprotectant in the cell wall of bacteria, lipoteichoic acid biopolymers. Adding 1% LTA to bacteria cultures immediately prior to freezing provides 50% survival rate, similar to the results obtained with 1% glycerol. In the absence of an additive, bacterial survival is negligible as measured with the resazurin cell viability assay. The mode of action for LTA cryoprotection is unknown. With a molecular weight of 3-5 kDa, it is unlikely to enter the cell cytoplasm. Our observations suggest that teichoic acids could provide a shell of liquid water around biofilms and planktonic bacteria, removing the need for brine veins to prevent bacterial freezing.

Rice, Charles V.; Middaugh, Amy; Wickham, Jason R.; Friedline, Anthony; Thomas, Kieth J.; Johnson, Karen; Zachariah, Malcolm; Garimella, Ravindranth

2012-10-01

470

Electrochemical destruction of organic acids  

SciTech Connect

An electrochemical process for removing organic acids from an aqueous waste stream has been characterized. Biological treatment of aqueous organic acid waste streams has been the typical means of degrading organic acids, and the resultant biosludge is landfilled. In the electrochemical approach, aqueous organic acids may be efficiently converted to useful fuel in a one or two electron process. The possible reactions occurring are outlined here. The electrolysis of the sodium salts of acetic, propionic, and butyric acids has been studied both as single component solutions and mixtures. The reaction products as well as relative rates of destruction of the acid salts were measured. The effect of experimental variables such as current density, temperature, and anode material on the current efficiency and product distribution was investigated. Electrode stability due to platinum corrosion was identified as the major limitation to the process.

Gendes, J.D.; Hartsough, D. [Electrosynthesis Co., Inc., Lancaster, NY (United States); Super, J.D. [DuPont Specialty Chemicals, Deepwater, NJ (United States)

1994-12-31

471

Molecular Structure of Phosphoric acid  

NSDL National Science Digital Library

Phosphoric acid was first made in 1774 by K.W. Scheele and J.G. Gahn from bone ash. Phosphoric acid is made by treating calcium phosphate rock with sulfuric acid, followed by filtration. It is by this process that almost 10 tons of phosphoric acid are produced in the United States each year. The compound is primarily used to manufacture some pharmaceutical products, fertilizers and as a flavoring agent in coca-cola. The steel industry uses it to clean and rust-proof their steel. Phosphoric acid is also used in the process of soil stabilization, and as a catalyst in the production of propylene and butene polymers, ethylbenzene, and cumene. In recent years though the industry has moved away from using phosphoric acid as a ingredient in detergents because of the harmful effect that Phosphates have on lakes a process called lake eutrophication.

2002-09-10

472

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

473

Enzymatic tRNA acylation by acid and alpha-hydroxy acid analogues of amino acids.  

PubMed

Incorporation of unnatural amino acids with unique chemical functionalities has proven to be a valuable tool for expansion of the functional repertoire and properties of proteins as well as for structure-function analysis. Incorporation of alpha-hydroxy acids (primary amino group is substituted with hydroxyl) leads to the synthesis of proteins with peptide bonds being substituted by ester bonds. Practical application of this modification is limited by the necessity to prepare corresponding acylated tRNA by chemical synthesis. We investigated the possibility of enzymatic incorporation of alpha-hydroxy acid and acid analogues (lacking amino group) of amino acids into tRNA using aminoacyl-tRNA synthetases (aaRSs). We studied direct acylation of tRNAs by alpha-hydroxy acid and acid analogues of amino acids and corresponding chemically synthesized analogues of aminoacyl-adenylates. Using adenylate analogues we were able to enzymatically acylate tRNA with amino acid analogues which were otherwise completely inactive in direct aminoacylation reaction, thus bypassing the natural mechanisms ensuring the selectivity of tRNA aminoacylation. Our results are the first demonstration that the use of synthetic aminoacyl-adenylates as substrates in tRNA aminoacylation reaction may provide a way for incorporation of unnatural amino acids into tRNA, and consequently into proteins. PMID:18067322

Owczarek, Alina; Safro, Mark; Wolfson, Alexey D

2008-01-01

474

Enantioselective synthesis of pentacycloanammoxic acid.  

PubMed

A highly effective enantioselective synthesis of pentacycloanammoxic acid (1), an unusual naturally occurring fatty acid from Candidatus Brocadia anammoxidans, has been accomplished. The C20-structure of 1 was assembled with stereocontrol from four building blocks, cyclobutene, 2-cyclopentenone, the chiral silylcyclopentenone 6, and 7-bromoheptanoic acid. Both 1 and its enantiomer are now available in quantities that should facilitate future studies on the mode of biosynthesis which appears to be unprecedented. PMID:16522072

Mascitti, Vincent; Corey, E J

2006-03-15

475

Total synthesis of (+/-)-pentacycloanammoxic acid.  

PubMed

The first total synthesis of (+/-)-pentacycloanammoxic acid/methyl ester (1), an unusual naturally occurring fatty acid from Candidatus Brocadia anammoxidans, has been accomplished by the sequence of reactions shown in Scheme 1. The C20-structure of 1 was assembled with stereocontrol from three building blocks: cyclooctatetraene, 2-cyclopentenone, and 7-bromoheptanoic acid. The synthesis of 1 confirms the proposed structure of 1. The mode of biosynthesis and absolute configuration have yet to be clarified. PMID:15571387

Mascitti, Vincent; Corey, E J

2004-12-01

476

Zirconium in sulfuric acid applications  

SciTech Connect

Zirconium is one of the few metals that resists attack by sulfuric acid at concentrations up to 75% and temperatures to boiling and above. This capability makes zirconium a good structural metal for use in 40 to 65% H/sub 2/SO/sub 4/ up to boiling temperatures and for weak acid concentrations at elevated temperatures. Zirconium's corrosion properties in sulfuric acid solutions are compared with nickel base alloys. Examples of applications and limitations in the use of zirconium are presented.

Webster, R.T.; Yau, T.L.

1986-02-01

477

Fungal metabolites of sorbic acid  

Microsoft Academic Search

A number of fungal detoxification reactions of sorbic acid have been reviewed. These include decarboxylation to give trans?1,3?pentadiene, esterification to give ethyl sorbate, reduction to give 4?hexenol and 4?hexenoic acid. It was shown that seven Penicillium species could convert sorbic acid into 1,3?pentadiene whilst P. bilaii, P. fellutanum and P. glabrum did not. However, most Eurotium species were unable to

Judith. L. Kinderlerer; P. V. Hatton

1990-01-01

478

Simulated acid rain on crops  

Microsoft Academic Search

In 1981, simulated HâSOâ acid rain was applied to alfalfa and tall fescue and a 2:1 ratio of HâSOâ:HNOâ 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 att