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1

Relative Acidity and Basicity of Sulphanilamide and p-Aminobenzoic Acid  

Microsoft Academic Search

SINCE no determination of the relative acidic or basic dissociation constants of sulphanilamide appears to have been published, this drug was potentio-metrically titrated against N\\/1 hydrochloric acid followed by N\\/1 sodium hydroxide. p-Aminobenzoic acid and p-aminophenylacetic acid were treated similarly for purposes of comparison. In each case, a solution of freshly recrystallized, pure material (0.0005 gm. mol. in 20 ml.

Adrien Albert; Reginald Goldacre

1942-01-01

2

Direct condensation polymerization of N-alkylated p-aminobenzoic acid and packing of rigid-rod main chains with flexible side chains  

Microsoft Academic Search

Direct condensation polymerization of N-alkylated p-aminobenzoic acid, in which methyl, propyl, butyl, pentyl, heptyl, octyl and heptadecyl substituents were used as the alkyl group, was performed using hexachloroethane, triphenylphosphine and pyridine as condensation reagents. Pale-yellow N-alkylated poly(p-benzamide) (PABAn) polymers, where n is the number of carbon atoms of the alkyl side chain, were obtained in 46–87% yields with an inherent

Yuji Shibasaki; Yoko Abe; Natsuki Sato; Atsuhiro Fujimori; Yoshiyuki Oishi

2010-01-01

3

Formaldehyde removal by Rayon-based activated carbon fibers modified by P -aminobenzoic acid  

Microsoft Academic Search

We impregnated Rayon-based activated carbon fibers (ACFs) by p-aminobenzoic acid (PABA) and systematically investigated their porous structure, surface chemistry, and formaldehyde removal\\u000a behavior. Using standard nitrogen adsorption analysis, we found that the specific surface area, the micropore volume, and\\u000a the total pore volume decreased with increasing concentration of PABA. Through elemental analysis and X-ray photoelectron\\u000a spectroscopy, it was found that

Haiqin Rong; Zhenyu Liu; Qilin Wu; Ding Pan; Jingtang Zheng

2010-01-01

4

Synthesis, characterization and cation adsorption of p-aminobenzoic acid intercalated on calcium phosphate  

SciTech Connect

Graphical abstract: Scanning electron microscopy photographs of calcium phosphate (a) and intercalated with p-aminobenzoic acid (b). Highlights: ? Calcium phosphate was intercalated with p-aminobenzoic acid. ? Guest molecule contains nitrogen and oxygen atoms from amine and carboxylic groups. ? These basic centers are potentially useful for cation coordination in ethanol solution. ? Crystal morphology of compounds is lamellar, it agrees with expected structural characteristics. -- Abstract: Crystalline lamellar calcium phosphate retained 4-aminobenzoic acid inside its cavity without leaching. The intense infrared bands in the 1033 and 1010 cm{sup ?1} interval confirmed the presence of the phosphonate groups attached to the inorganic layer, with sharp and intense peaks in X-ray diffraction patterns, which gave basal distances of 712 and 1578 pm for the original and the intercalated compounds, respectively. Solid-state {sup 31}P nuclear magnetic resonance spectra presented only one peak for the phosphate groups attached to the main inorganic polymeric structure near ?2.4 ppm. The adsorption isotherms from ethanol gave the maximum adsorption capacities of 6.44 and 3.34 mmol g{sup ?1} for nickel and cobalt, respectively, which stability constant and distribution coefficient followed Co > Ni.

Silva, Camila F.N. [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil)] [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Lazarin, Angélica M., E-mail: amlazarin2@uem.br [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Sernaglia, Rosana L.; Andreotti, Elza I.S. [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil)] [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil)

2012-06-15

5

Synthesis, Crystal Structure and Biological Activity of 2-Hydroxyethylammonium Salt of p-Aminobenzoic Acid.  

PubMed

p-Aminobenzoic acid (pABA) plays important roles in a wide variety of metabolic processes. Herein we report the synthesis, theoretical calculations, crystallographic investigation, and in vitro determination of the biological activity and phytotoxicity of the pABA salt, 2-hydroxyethylammonium p-aminobenzoate (HEA-pABA). The ability of neutral and anionic forms of pABA to interact with TIR1 pocket was investigated by calculation of molecular electrostatic potential maps on the accessible surface area, docking experiments, Molecular Dynamics and Quantum Mechanics/Molecular Mechanics calculations. The docking study of the folate precursor pABA, its anionic form and natural auxin (indole-3-acetic acid, IAA) with the auxin receptor TIR1 revealed a similar binding mode in the active site. The phytotoxic evaluation of HEA-pABA, pABA and 2-hydroxyethylamine (HEA) was performed on the model plant Arabidopsis thaliana ecotype Col 0 at five different concentrations. HEA-pABA and pABA acted as potential auxin-like regulators of root development in Arabidopsis thaliana (0.1 and 0.2 mM) and displayed an agravitropic root response at high concentration (2 mM). This study suggests that HEA-pABA and pABA might be considered as potential new regulators of plant growth. PMID:25054237

Crisan, Manuela E; Bourosh, Paulina; Maffei, Massimo E; Forni, Alessandra; Pieraccini, Stefano; Sironi, Maurizio; Chumakov, Yurii M

2014-01-01

6

Synthesis, Crystal Structure and Biological Activity of 2-Hydroxyethylammonium Salt of p-Aminobenzoic Acid  

PubMed Central

p-Aminobenzoic acid (pABA) plays important roles in a wide variety of metabolic processes. Herein we report the synthesis, theoretical calculations, crystallographic investigation, and in vitro determination of the biological activity and phytotoxicity of the pABA salt, 2-hydroxyethylammonium p-aminobenzoate (HEA-pABA). The ability of neutral and anionic forms of pABA to interact with TIR1 pocket was investigated by calculation of molecular electrostatic potential maps on the accessible surface area, docking experiments, Molecular Dynamics and Quantum Mechanics/Molecular Mechanics calculations. The docking study of the folate precursor pABA, its anionic form and natural auxin (indole-3-acetic acid, IAA) with the auxin receptor TIR1 revealed a similar binding mode in the active site. The phytotoxic evaluation of HEA-pABA, pABA and 2-hydroxyethylamine (HEA) was performed on the model plant Arabidopsis thaliana ecotype Col 0 at five different concentrations. HEA-pABA and pABA acted as potential auxin-like regulators of root development in Arabidopsis thaliana (0.1 and 0.2 mM) and displayed an agravitropic root response at high concentration (2 mM). This study suggests that HEA-pABA and pABA might be considered as potential new regulators of plant growth.

Crisan, Manuela E.; Bourosh, Paulina; Maffei, Massimo E.; Forni, Alessandra; Pieraccini, Stefano; Sironi, Maurizio; Chumakov, Yurii M.

2014-01-01

7

Use of the conjugate of disulphated ursodeoxycholic acid with p-aminobenzoic acid for the detection of intestinal bacteria  

Microsoft Academic Search

The disulphate ester of ursodeoxycholyl-p-aminobenzoic acid (PABA-UCDA) was synthesised and compared with PABA-UDCA for its use in detection of intestinal bacteria. This compound, PABA-UDCA disulphate, had characters in common with PABA-UDCA in that it was deconjugated by cholylglycine hydrolase to release free PABA and bacteria that split glycocholic acid deconjugated PABA-UDCA disulphate. Further, in rat experiments urinary excretions of PABA

M Takahashi; T Konishi; Y Maeda; Y Matsugu; F Akazawa; T Eto; M Okajima; K Uchida; Y Masaoka; K Okada

1993-01-01

8

Synthesis, crystal structure, magnetism and specific heat of a new copper(II) compound with p-aminobenzoic acid  

Microsoft Academic Search

In this work we present the synthesis, crystal structure, magnetic and specific heat measurements of a new monomeric copper(II) compound, in which the metal ion is coordinated to two p-aminobenzoic acid (PABA) molecules and two chloride ions. This compound with formula [CuCl2(C7H7NO2)2] presents a peculiar crystalline structure packing, showing hydrogen-bonds between carboxylic acid groups and short N–H?Cl contacts resulting in

Guilherme P. Guedes; Fernanda F. Farias; Miguel A. Novak; Fernando L. de A. Machado; Maria G. F. Vaz

2011-01-01

9

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

Microsoft Academic Search

Ternary terbium complexes with p-aminobenzoic acid (HL), [TbL3(DMSO)(H2O)]2 (1), [TbL3(DMF)(H2O)]2 (2) and [TbL3(Bpy)(H2O)]2·2H2O (3) (DMSO=dimethyl sulfoxide, DMF=N, N- dimethylformamide, Bpy=2, 2?- bipyridyl) have been synthesized, and their crystal structures determined. The luminescence properties of these complexes, including both the emission quantum yield and the fluorescence lifetime, have been investigated. The effect of a second ligand on the crystal structure and

Liang Oyang; Hao-Ling Sun; Xin-Yi Wang; Jun-Ran Li; Dao-Bo Nie; Wen-Fu Fu; Song Gao; Kai-Bei Yu

2005-01-01

10

INHIBITION OF ESCHERICHIA COLI BY p-AMINOBENZOIC ACID AND ITS REVERSAL BY p-HYDROXYBENZOIC ACID  

PubMed Central

p-Aminobenzoic acid (PABA) exerts three metabolic effects on E. coli: it acts as a normal vitamin at low concentrations, as a source of another vitamin, p-hydroxybenzoic acid (POB), at moderate concentrations, and as a growth inhibitor at high concentrations (150 to 1600 µg./ml.). The inhibition is competitively reversed by POB in 1/100 the concentration of PABA. The inhibition is also reversed to a limited extent by shikimic acid and compound X, precursors of POB. p-Nitrobenzoic acid is an inhibitory competitor of both POB and PABA. The retardation of growth produced by PABA and other competitive analogues of POB (p-nitrobenzoic acid; 4,4'-dihydroxydiphenyl sulfone; phenosulfazole) is converted to complete bacteriostasis by the addition of L-aspartic acid in a remarkably low concentration (1 µg./ml.)) without change in the competitive ratio with POB. The mechanism underlying this synergism is not clear. In contrast to wild type, mutants that require POB not only are inhibited by much lower concentrations of the above analogues, but also show inhibition by weaker competitors of POB such as p-hydroxybenzenesulfonamide, p-chlorobenzoic acid, and p-fluorobenzoic acid.

Davis, Bernard D.

1951-01-01

11

[Comparative study on separation of p-aminobenzoic and p-hydroxy-benzoic acids by reactive extraction].  

PubMed

The comparative study on reactive extraction of p-aminobenzoic and p-hydroxybenzoic acid with Amberlite LA-2 and D2EHPA in two solvents with different polarity (n-heptane and dichloromethane) indicated that the nature of the specific substituents, extractant type and solvent polarity control the extraction mechanism. Although the reactive extraction with Amberlite LA-2 of the two acids occurs by means of rather similar interfacial reactions, the extraction with D2EHPA is based on different mechanisms, due to the participation of the two different substituents of aminic and phenolic type. In all cases, the most efficient extractions have been reached for the combination Amberlite LA-2-dichloromethane. PMID:20209796

Galaction, Anca-Irina; Ca?caval, D

2008-01-01

12

Simultaneous removal of acetaldehyde, ammonia and hydrogen sulphide from air by active carbon impregnated with p -aminobenzoic acid, phosphoric acid and metal compounds  

Microsoft Academic Search

Simultaneous removal of acetaldehyde, ammonia, and hydrogen sulphide from air by the impregnated active carbon was studied at 25‡C. p-Aminobenzoic acid (PABA), phosphoric acid (H3PO4), and metal compound such as copper (II) chloride dihydrate (CuCl2·2H2O), copper (II) nitrate trihydrate (Cu(NO3)2·3H2O), and potassium iodide (KI) were investigated as impregnation ingredients. Acetaldehyde and ammonia were simultaneously removed from air by the active

M. Sugiura; K. Fukumoto

1994-01-01

13

Use of the conjugate of disulphated ursodeoxycholic acid with p-aminobenzoic acid for the detection of intestinal bacteria.  

PubMed Central

The disulphate ester of ursodeoxycholyl-p-aminobenzoic acid (PABA-UCDA) was synthesised and compared with PABA-UDCA for its use in detection of intestinal bacteria. This compound, PABA-UDCA disulphate, had characters in common with PABA-UDCA in that it was deconjugated by cholylglycine hydrolase to release free PABA and bacteria that split glycocholic acid deconjugated PABA-UDCA disulphate. Further, in rat experiments urinary excretions of PABA were measured for six hours after oral administration of 15 mg PABA-UDCA disulphate. Ten control rats excreted (mean (SE) 188.2 (13.6) micrograms of PABA; 10 rats with an intestinal stagnant loop excreted more (530.1 (30.1) micrograms; p < 0.001): whereas 10 rats in each of three groups pretreated by oral administration of various antibiotics excreted less (polymixin B+tinidazole, 4.9 (1.6) micrograms; kanamycin, 31.0 (4.7) micrograms; clindamycin 40.9 (5.5) micrograms; p < 0.001). By contrast with PABA-UDCA, PABA-UDCA disulphate was not actively absorbed from any part of the small intestine in everted gut sac experiments, and showed poor recovery from bile after its intraileal instillation in rats. This indicated that PABA-UDCA disulphate is a single pass type substance in the gut and its oral administration test reflects the sum of the activities of bacteria in the small intestine and colon. The disulphate was easily soluble in water and this allowed its application in an in vitro test involving PABA-UDCA disulphate incubation with intraperitoneal pus (PABA-UDCA disulphate incubation test) from patients with peritonitis. This test was carried out on six patients with peritonitis, and the severity of bacterial peritonitis was expressed quantitatively. From the results obtained PABA-UDCA disulphate was considered a good material to detect intestinal bacteria.

Takahashi, M; Konishi, T; Maeda, Y; Matsugu, Y; Akazawa, F; Eto, T; Okajima, M; Uchida, K; Masaoka, Y; Okada, K

1993-01-01

14

Room-temperature luminescence properties of p-aminobenzoic acid and 4-phenylphenol adsorbed on alpha-cyclodextrin\\/NaCl mixtures  

Microsoft Academic Search

The solid-surface fluorescence and phosphorescence quantum yield values and phosphorescence lifetime values were obtained for p-aminobenzoic acid (PABA) and 4-phenylphenol adsorbed on ..cap alpha..-cyclodexrin\\/NaCl mixtures. From the luminescence quantum yield and phosphorescence lifetime data, the triplet formation efficiency values, the phosphorescence rate constants, and the rate constants for radiationless transition from the triplet state were determined for PABA and 4-phenylphenol

J. M. Bellow; R. J. Hurtubise

1988-01-01

15

[Analysis of monosaccharides and uronic acids in polysaccharides by pre-column derivatization with p-aminobenzoic acid and high performance liquid chromatography].  

PubMed

An ion-pair reversed-phase high performance liquid chromatographic (RP-HPLC) method for the simultaneous determination of carbohydrate and uronic acids was developed. p-Aminobenzoic acid (p-AMBA) was used for pre-column derivatization of the analytes, enabling fluorescence (lambda(ex) = 313 nm, lambda(em) = 358 nm) or ultraviolet (UV at 303 nm) detection. Reaction conditions such as reaction temperature and reaction time were optimized. Atlantis dC18 column with hydrophilic end capping was selected for the separation of derivatives. Effects of mobile phase compositions such as ion pairs and their concentrations and pH on the retention behaviors and separation results of 9 monosaccharides and 2 uronic acids were investigated. Derivatives of fructose, galactose, glucose, mannose, xylose, arabinose, ribose, galacturonic acid, fucose, glucuronic acid and rhamnose were separated within 42 min, applying tetrabutyl ammonium hydrogen bisulfate (TBAHSO4) as the ion pair reagent. The detection limits were between 3.38 x 10(-8) mol/L and 176 x 10(-8) mol/L for fluorescence detection and between 2.55 x 10(-7) mol/L and 13.4 x 10(-7) mol/L for UV detection. Good linearities were obtained with correlation coefficients (r2) above 0.99. The relative standard deviations (RSDs) of the peak area of the derivatives in 12 - 51 h after derivatization were from 2.5% to 3.9%. This method has been applied for the determination of mono-/disaccharides and uronic acids in spirulina polysaccharide after dissolved in trifluoroacetic acid solution (2 mol/L). The results showed this method is suitable for the analysis of monosaccharide compositions in polysaccharides. PMID:17432580

Hao, Guitang; Chen, Shangwei; Zhu, Song; Yin, Hongping; Dai, Jun; Cao, Yuhua

2007-01-01

16

New soluble poly(amide–imide–imide)s based on tetraimide-dicarboxylic acid condensed from 4,4 ?-oxydiphthalic anhydride, 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone, and p-aminobenzoic acid, and various aromatic diamines  

Microsoft Academic Search

A new-type tetraimide-dicarboxylic acid (I) was synthesized starting from the ring-opening addition of p-aminobenzoic acid, 4,4?-oxydiphthalic anhydride, and 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS) at a 2:2:1 molar ratio in N-methyl-2-pyrrolidone (NMP), followed by cyclodehydration to the diacid I. A series of poly(amide–imide–imide)s (IIIa–i) with inherent viscosities of 0.71–0.99 dl\\/g was prepared by triphenyl phosphite-activated polycondensation from the tetraimide-diacid I with various aromatic diamines

Chin-Ping Yang; Ruei-Shin Chen; Chi-Shu Wei

2002-01-01

17

A solid-phase extraction and size-exclusion liquid chromatographic method for polyethylene glycol 25 p-aminobenzoic acid determination in urine: validation for urinary excretion studies of users of sunscreens.  

PubMed

No previous publications about percutaneous absorption of polyethylene glycol 25 p-aminobenzoic acid (PEG-25 PABA) have been found in the literature and the expected levels to be found in human urine after sunscreens use are unknown. The method proposed here is suitable to determine PEG-25 PABA in the urine of sunscreens users in order to carry out studies on body accumulation/excretion. It is based on solid-phase extraction (SPE) with size-exclusion liquid chromatography determination. Solid-phase extraction allows the analyte to be retained and subsequently eluted for a clean-up, using a silica-based cartridge. The size-exclusion liquid chromatography of the eluted allows the rest of matrix interferences to be avoided. Fluorescence intensity was measured at lambda(em)=350 nm (lambda(exc)=300 nm). The sensitivity of the proposed method is in the order of 450+/-5 mLng(-1) and the detection limit (3S(y/x)/b) in the measured solutions is in the order of 13 ngmL(-1), that is 2.6 ngmL(-1) in urine samples. The method enables PEG-25 PABA to be determined in both, spiked and unspiked human urine samples. Results obtained for spiked human urine samples (11-100 ngmL(-1)) demonstrated the accuracy of the method. The mean relative standard deviation of the results was in the order of 3-10%. Three volunteers applied a sunscreen lotion containing a 8% PEG-25 PABA sunscreen cream and their urinary excretion was controlled from the moment of application until the excreted amounts were no longer detectable. PMID:18328324

Balaguer, A; Chisvert, A; Salvador, A; Herraez, M; Diez, O

2008-03-24

18

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.

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

2008-01-01

19

Synthesis, structure, growth and characterization of a novel organic NLO single crystal: Morpholin-4-ium p-aminobenzoate  

SciTech Connect

Highlights: ? A new organic NLO crystal morpholin-4-ium p-aminobenzoate has been grown for the first time. ? The structure is reported for the first time in the literature. ? Thermal, optical and SHG studies suggest its suitability for various NLO applications. -- Abstract: The title compound, morpholin-4-ium p-aminobenzoate (MPABA)(C{sub 4}H{sub 10}NO{sup +},C{sub 7}H{sub 6}NO{sub 2}{sup ?}), has been synthesized for the first time by the addition of morpholine with 4-aminobenzoic acid in equi-molar ratio and good quality single crystals have been grown by solution growth technique using methanol as a solvent. The molecular structure of the compound was solved and refined by Direct Methods using SHELXS97 and full-matrix least-squares technique using SHELXL97, respectively. MPABA crystallizes in a monoclinic system with unit cell parameters, a = 5.948(5) ?, b = 18.033(4) ?, c = 10.577(5) ?, ? = 90.40(1)° and non-centrosymmetric space group Cc. The experimentally measured density and chemical compositions were found to be in good agreement with the theoretical values. The phases and functional groups of MPABA have been identified and confirmed through powder X-ray diffraction and Fourier transform infrared (FTIR) studies, respectively. The thermal stability and decomposition details were studied through TG/DTA thermograms. The UV–visible transmission spectra were recorded for the grown crystal and its NLO characteristic was explored by powder second harmonic generation (SHG) studies.

Shanmugam, G. [Department of Physics, Anna University of Technology Tiruchirappalli, Tiruchirappalli 620024 (India)] [Department of Physics, Anna University of Technology Tiruchirappalli, Tiruchirappalli 620024 (India); Ravi Kumar, K.; Sridhar, B. [X-ray Crystallography Division, Indian Institute of Chemical Technology, CSIR, Hyderabad 500007 (India)] [X-ray Crystallography Division, Indian Institute of Chemical Technology, CSIR, Hyderabad 500007 (India); Brahadeeswaran, S., E-mail: sbrag67@yahoo.com [Department of Physics, Anna University of Technology Tiruchirappalli, Tiruchirappalli 620024 (India)

2012-09-15

20

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

Microsoft Academic Search

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

Chundong Zhang; Hui Wan; Lijun Xue; Guofeng Guan

2011-01-01

21

Hypothesis: Is Accumulation of a Furan Dicarboxylic Acid (3Carboxy4Methyl5Propyl2-Furanpropanoic Acid) Related to the Neurological Abnormalities in Patients with Renal Failure?  

Microsoft Academic Search

The plasma concentrations of a lipophilic furan dicarboxylic acid (3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid; 5-propyl FPA), which is highly bound to albumin and not removed by haemodialysis, have been measured in patients with renal impairment who were not dialysis dependent or who were treated by either haemodialysis or peritoneal dialysis. Neurological abnormalities were assessed as absent, moderate, or severe. A relationship was observed

M. G. Costigan; C. A. O’Callaghan; W. E. Lindup

1996-01-01

22

Modulation of peripheral Na(+) channels and neuronal firing by n-butyl-p-aminobenzoate.  

PubMed

n-butyl-p-aminobenzoate (BAB), a local anesthetic, is administered epidurally in cancer patients to treat pain that is poorly controlled by other drugs that have a number of adverse effects. The purpose of the study was to unravel the mechanisms underlying the apparent selective pain suppressant effect of BAB. We used the whole-cell patch-clamp technique to record Na(+) currents and action potentials (APs) in dissociated, nociceptive dorsal root ganglion (DRG) cells from rats, two types of peripheral sensory neuron Na(+) channels (Nav1.7 and Nav1.8), and the motor neuron-specific Na(+) channel (Nav1.6) expressed in HEK293 cells. BAB (1-100?M) inhibited, in a concentration-dependent manner, the depolarization evoked repetitive firing in DRG cells, the three types of Na(+) current expressed in HEK293 cells, and the TTXr Na(+) current of the DRG neurons. BAB induced a use-dependent block that caused a shift of the inactivation curve in the hyperpolarizing direction. BAB enhanced the onset of slow inactivation of Nav1.7 and Nav1.8 currents but not of Nav1.6 currents. At clinically relevant concentrations (1-100?M), BAB is thus a more potent inhibitor of peripheral TTX-sensitive TTXs, Nav1.7 and TTX-resistant NaV1.8 Na(+) channels than of motor neuron axonal Nav1.6 Na(+) channels. BAB had similar effects on the TTXr Na(+) channels of rat DRG neurons and Nav1.8 channels expressed in HEK293 cells. The observed selectivity of BAB in treating cancer pain may be due to an enhanced and selective responsiveness of Na(+) channels in nociceptive neurons to this local anesthetic. PMID:24486399

Thériault, Olivier; Poulin, Hugo; Sculptoreanu, Adrian; de Groat, William C; O'Leary, Micheal E; Chahine, Mohamed

2014-03-15

23

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

Microsoft Academic Search

In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose\\u000a (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate\\u000a (CSD, CaSO4·2H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid\\u000a phase

Van Viet Thai; Byong-Taek Lee

2010-01-01

24

21 CFR 184.1660 - Propyl gallate.  

Code of Federal Regulations, 2010 CFR

...the n -propylester of 3,4,5-trihydroxybenzoic acid (C10 H12 O5 ). Natural occurrence of propyl...reported. It is commercially prepared by esterification of gallic acid with propyl alcohol followed by distillation to...

2009-04-01

25

21 CFR 184.1660 - Propyl gallate.  

Code of Federal Regulations, 2010 CFR

...the n -propylester of 3,4,5-trihydroxybenzoic acid (C10 H12 O5 ). Natural occurrence of propyl...reported. It is commercially prepared by esterification of gallic acid with propyl alcohol followed by distillation to...

2010-01-01

26

Phenolic acid derivatives with potential anticancer properties––a structure–activity relationship study. Part 1: Methyl, propyl and octyl esters of caffeic and gallic acids  

Microsoft Academic Search

The antiproliferative and cytotoxic properties of polyphenolic acid derivatives, structurally related with the natural models caffeic and gallic acids, have been tested in human cervix adenocarcinoma cells (HeLa). Simultaneous structural information was obtained for these compounds through theoretical ab initio methods. This study was conducted for the following esters: methyl caffeate (MC, 1), propyl caffeate (PC, 2), octyl caffeate (OC,

S. M. Fiuza; C. Gomes; L. J. Teixeira; M. T. Girão da Cruz; M. N. D. S. Cordeiro; N. Milhazes; F. Borges; M. P. M. Marques

2004-01-01

27

Studies on the growth, thermal and optical properties of 4-aminopyridinium p-aminobenzoate dihydrate single crystals  

NASA Astrophysics Data System (ADS)

4-aminopyridinium p-aminobenzoate dihydrate (4APAB) compound was synthesized successfully and single crystals were grown by slow evaporation solution growth technique. Single crystal X-ray diffraction study was conducted to evaluate the cell parameters of grown crystal. The crystalline perfection of 4APAB crystal was assessed by HRXRD studies. Thermal studies revealed the thermal stability of grown crystal up to 126 °C. The optical transmittance window and lower cut-off wavelength of 4APAB crystal were estimated by using UV-vis-NIR studies. The second harmonic efficiency of 4APAB was measured by powder test using Nd:YAG laser radiation. The dielectric tensor studies revealed that 4APAB crystal shows normal dielectric behavior. The single and multiple shots laser damage threshold values of grown crystal were measured.

Sornamurthy, B. M.; Peramaiyan, G.; Pandi, P.; Das, S.; Bhagavannarayana, G.; Manivannan, V.; Mohan Kumar, R.

2014-07-01

28

Reaction of 2-hydroxy-2-propyl radical with maleic and fumaric acids in aqueous solution: pH dependence  

NASA Astrophysics Data System (ADS)

2-Hydroxy-2-propyl radical reacts with highly different rate coefficients ( k) with the three protonation forms of maleic and fumaric acids. With protonated fumaric acid k is high, (2.1 ± 0.4) × 10 9 mol -1 dm 3 s -1 due to the nucleophilic character of IP reaction and the electron withdrawing -COOH groups. With mono- and dianion molecules the k's are smaller, (6.6 ± 0.7) × 10 8 and (3.1 ± 3.0) × 10 7 mol -1 dm 3 s -1. In maleic acid k for the monoanion is higher ((1.34 ± 0.03) × 10 9 mol -1 dm 3 s -1) than for protonated and dianion species, (5.6 ± 0.6) × 10 8 and (3.5 ± 3.1) × 10 7 mol -1 dm 3 s -1. The high k is interpreted in terms of cyclic structure and charge localization between carboxylic groups.

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

2007-04-01

29

Poly(pyrrole-co-pyrrole propylic acid) film and its application in label-free surface plasmon resonance immunosensors.  

PubMed

In this work, surface plasmon resonance (SPR) was used to study protein immobilization on poly(pyrrole-co-pyrrole propylic acid) (PPy/PPa) for immunosensing applications. SPR was employed to in situ monitor the electropolymerization process and to control thickness of the PPy/PPa copolymer film. Goat IgG as a model protein was covalently immobilized on the carboxyl-containing film through EDC/NHS as the coupling reagents. The effect of pyrrole propylic acid (Pa) proportion in the deposition solution on the protein immobilization capability was systemically investigated. The immobilization efficiency was demonstrated by a label-free SPR immunosensor. The heterogeneous kinetics of the immune reaction was discussed. This work could provide a facile method to immobilize proteins on an electrode surface by electropolymerized copolymer, and renders a universal approach to in situ study the protein immobilization process and sensing kinetics for scientific insights of the heteroimmunosensing scheme particularly in surface chemistry and molecular biology for further improvement of immunosensors. PMID:19068327

Hu, Weihua; Li, Chang Ming; Dong, Hua

2008-12-01

30

p-Aminobenzoate Synthesis in Escherichia Coli: Purification and Characterization of PabB as Aminodeoxychorismate Synthase and Enzyme X as Aminodeoxychorismate Lyase  

Microsoft Academic Search

The Escherichia coli pabA and pabB genes have been overexpressed separately and in tandem. Using purified PabB, we have confirmed the recent suggestion that PabB needs an additional protein, enzyme X, to convert chorismate and NH_3 to p-aminobenzoate (PABA). With chorismate and NH_3, pure PabB generates an intermediate presumed to be 4-amino-4-deoxychorismate based upon UV\\/visible spectroscopy and enzymatic and nonenzymatic

Qi-Zhuang Ye; Jun Liu; Christopher T. Walsh

1990-01-01

31

Interaction Between Two Dicarboxylate Endogenous Substances, Bilirubin and an Uremic Toxin, 3Carboxy4Methyl5Propyl2-Furanpropanoic Acid, on Human Serum Albumin  

Microsoft Academic Search

Purpose. Two dicarboxylate endogenous substances, bilirubin (BR) and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF), have a very high affinity to human serum albumin (HSA). This study was undertaken to clarify the existence of a dicarboxylate binding site on HSA.

Yasuhiro Tsutsumi; Toru Maruyama; Akira Takadate; Masafumi Goto; Hiroshi Matsunaga; Masaki Otagiri

1999-01-01

32

Production of antiserum for sensitive enzyme-linked immunosorbent assay of 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid by chemiluminescence  

Microsoft Academic Search

To obtain a specific antiserum for use in enzymelinked immunosorbent assay (ELISA) of 3-carboxy-4-methyl-5-propyl-2-furanpropanoic\\u000a acid (CMPF), we prepared a haptencarrier conjugate in which the CMPF hapten was linked to a carrier protein through the 5-(1-hydrazopropyl)\\u000a group. The antisera raised against this antigen in guinea pigs had excellent specificity for CMPF, showing little cross-reactivity\\u000a with closely related compounds and no significant

Touichi Tanaka; Hideharu Ikebuchi; Jun-ichi Sawada; Yoshiko Tanaka

1998-01-01

33

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 dewaxed, acid-form peats have been studied by meas of swelling measurements. The results for sulfoxides are displayed as heteromolecular sorption isotherms, which plot a...

34

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...

35

Blockade of human neutrophil activation by 2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]propoxy]phenoxy]benzoic acid (LY293111), a novel leukotriene B 4 receptor antagonist  

Microsoft Academic Search

Leukotriene B4 (LTB4), a naturally occurring pro-inflammatory product of arachidonic acid metabolism, has been associated with human inflammatory disease. This study compares the abilities of two LTB4 receptor antagonists, 2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]-propoxy]phenoxy]benzoic acid (LY293111) and 7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)-propoxy]-3, 4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid (SC-41930), to displace LTB4 binding and their functional blockade of human neutrophil activation. LY293111 inhibited the binding of [3H]LTB4 with a Ki, of 25

Philip Marder; J. Scott Sawyer; Larry L. Froelich; Larry L. Mann; Stephen M. Spaethe

1995-01-01

36

Swelling of peats in liquid methyl, tetramethylene and propyl sulfoxides and in liquid propyl sulfone  

SciTech Connect

The interactions of methyl, tetramethylene, and propyl sulfoxides and propyl sulfone during sorption onto four dewaxed, acid-form peats have been studied by means of swelling measurements. The results for sulfoxides are displayed as heteromolecular sorption isotherms, which plot amount sorbed versus S=O group activity (molar density ratio relative to methyl sulfoxide). The present swelling data are compared to previous data for a homologous series of alcohols. Propyl sulfone apparently reacted with the peats during the sorption process, and one peat (Canadian) exhibited a dramatic 26% shrinkage in volume when exposed to this reagent for 8 weeks. Pyrolysis-GC-MS study of sulfone-doped Canadian peat found that propyl sulfide was the predominant pyrolysis product, although traces of propyl sulfoxide and sulfur dioxide were also found.

Lyon, W.G. (ManTech Environmental Research Services Corp., Ada, OK (United States). Robert S. Kerr Environmental Research Lab.)

1995-02-01

37

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

38

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...

39

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...

40

3-[[3-(Triethoxysilyl)propyl]amino]propane-1-sulfonic acid-poly(vinyl alcohol) cross-linked zwitterionic polymer electrolyte membranes for direct methanol fuel cell applications.  

PubMed

Recently, organic-inorganic nanocomposite zwitterionic polymer electrolyte membranes (PEMs) have attracted remarkable interest for application to the direct methanol fuel cell (DMFC) operated at intermediate temperature (100-200 degrees C). In this paper, we report the synthesis of an organic-inorganic hybrid zwitterionomer silica precursor with ammonium and sulfonic acid functionality by the ring-opening of 3-propanesultone under mild heating conditions and the preparation procedure of a proton-conductive and stable organic-inorganic zwitterion-poly(vinyl alcohol) (PVA) cross-linked PEM by sol-gel in aqueous media. Developed PEMs were extensively characterized by studying their physicochemical and electrochemical properties under DMFC operating conditions. These membranes were designed to possess all of the required properties of a proton-conductive membrane, namely, reasonable swelling, good mechanical, dimensional, and oxidative strength, flexibility, and low methanol permeability along with reasonable proton conductivity (4.85 x 10(-2) S cm(-1)) due to zwitterionic functionality. Moreover, from the selectivity parameter among all developed membranes, ZI-70 [zwitterionomer membrane with 70 wt % of PVA of 3-[[3-(triethoxysilyl)propyl]amino]propane-1-sulfonic acid in the membrane matrix], exhibited the best results in comparison to the Nafion117 membrane for DMFC applications. PMID:20355885

Tripathi, Bijay P; Shahi, Vinod K

2009-05-01

41

Gas chromatographic analysis of C 1 ?C 22 carboxylic acids esterified in aqueous solutions as n-propyl esters  

Microsoft Academic Search

C1?C22 carboxylic acids have been esterified in aqueous solution with n-propanol. Gas chromatographic analyses have been performed from a single chromatogram. It has been proven that esterification in the concentration range of [H2O]\\/[n-PrOH]=0.022–8.45 can be utilized for the quantitative determination of these carboxylic acids.

I. Molnár-Perl; M. Morvai

1986-01-01

42

Gas chromatographic analysis of C 2 ?C 16 dicarboxylic acids esterified in aqueous solutions as n-propyl esters  

Microsoft Academic Search

Summary  C2?C16 dicarboxylic acids were esterified in aqueous solution in the presence of sulfuric acid. Esterification in water\\/n-propanol\\u000a mixtures with mole ratios between 0.03 and 2.21 can be utilized for the quantitative determination of dicarboxylic acids by\\u000a gas chromatography. The presence of water does not interfere at water\\/n-propanol mole ratios below 0.45. For mole ratios above\\u000a 0.45 anhydrous sodium sulfate has

I. Molnár-Perl; M. Morvai

1987-01-01

43

Final Report On the Safety Assessment of Glycolic Acid, Ammonium, Calcium, Potassium, and Sodium Glycolates, Methyl, Ethyl, Propyl, and Butyl Glycolates, and Lactic Acid, Ammonium, Calcium, Potassium, Sodium, and Tea-Lactates, Methyl, Ethyl, Isopropyl, and Butyl Lactates, and Lauryl, Myristyl, and Cetyl Lactates  

Microsoft Academic Search

This report provides a review of the safety of Glycolic Acid, Ammonium, Calcium, Potassium, and Sodium Glycolates, Methyl, Ethyl, Propyl, and Butyl Glycolates, Lactic Acid, Ammonium, Calcium, Potassium, Sodium, and TEA-Lactates, and Lauryl, Myristyl, and Cetyl Lactates. These ingredients belong to a group known as alpha-hydroxy acids (AHAs). Products containing these ingredients may be for consumer use, salon use, or

F. A. Andersen

1998-01-01

44

Palladium(II) extraction with 1-{[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1 H -1,2,4-triazole from nitric acid solutions  

Microsoft Academic Search

Palladium(II) extraction from nitric acid solutions with 1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1H-1,2,4-triazole in toluene is studied. The reagent efficiently extracts palladium(II) from 0.2–6 M HNO3 by a coordination mechanism yielding the complex Pd2(NO3)4\\u000a S\\u000a 3 in the organic phase. The reagent can be used for selective separation of palladium(II) from nickel(II), copper(II), and\\u000a iron(III) in the specified aqueous phase acidity range.

R. A. Khisamutdinov; G. R. Anpilogova; Yu. I. Murinov; L. V. Spirikhin

2010-01-01

45

Copper(II) extraction with 1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1 H -1,2,4-triazole from hydrochloric acid solutions  

Microsoft Academic Search

Copper(II) extraction with 1-“[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl”-1H-1,2,4-triazole in toluene from hydrochloric acid solutions is studied. It is shown that copper(II) is most efficiently extracted\\u000a with this reagent from 3–5 M HCl solutions. For aqueous acidity of 3 mol\\/L HCl, the extraction is an exothermal process and\\u000a follows the coordination mechanism. The anion-exchange extraction mechanism predominates where HCl concentrations is greater\\u000a than 6 mol\\/L.

R. A. Khisamutdinov; G. R. Anpilogova; I. P. Baikova; Yu. I. Murinov

2010-01-01

46

Preliminary Toxicological Study of Bis-Dinitro-Propyl-Formal:Bis-Dinitro-Propyl-Acetal.  

National Technical Information Service (NTIS)

Bis-dinitro-propyl-formal:bis-dinitro-propyl-acetal (BDNPF:BDNPA) is used for industrial purposes primarily as a nitroplasticizer. The acute toxicity, primary skin irritation reaction, skin sensitivity reaction, eye irritation response, and dominant letha...

D. M. Smith G. A. Drake J. E. London J. S. Wilson L. M. Holland

1978-01-01

47

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

48

Desensitizer for N-Propyl Nitrate.  

National Technical Information Service (NTIS)

According to this invention, n-propyl nitrate is rendered insensitive to shock, i.e., is desensitized, by means of a low gamma gas. The low gamma gas is incorporated into the n-propyl nitrate in an amount sufficient to assure that when bubbles are formed ...

B. A. Breslow

1976-01-01

49

GRAS (Generally Recognized as Safe) Food Ingredients: Propyl Gallate.  

National Technical Information Service (NTIS)

The report summarizes the available scientific literature from 1920 to 1972, related to the 'safety' of propyl gallate as a food ingredient. Chemical information, biological data, and biochemical aspects of propyl gallate are given in a 48 page summary co...

1972-01-01

50

In vivo metabolism of the n-propyl homologues of delta-8- and delta-9-tetrahydrocannabinol in the mouse.  

PubMed

n-Propyl-delta-8-tetrahydrocannabinol (n-propyl-delta-8-THC and n-propyl-delta-9-THC were synthesized by condensation of (1S)-cis-verbenol with 5-n-propyl-1,3-dihydroxybenzene and administered to male Charles River CD-1 mice. Hepatic metabolites were isolated by solvent extraction and chromatography on Sephadex LH-20 and identified by gas chromatography/mass spectrometry. Seven metabolites were identified from each cannabinoid. Metabolism was similar to that previously observed from the penyl homologues, with the major biotransformation pathway being the production of 11-hydroxy-propyl-THCs and their oxidation to carboxylic acid metabolites. Other metabolites were mainly hydroxylated derivatives of these compounds and the corresponding 11-alcohol. Less hydroxylation at C(8) was found with n-propyl-delta-9-THC than with the pentyl homologue, and the monohydroxy metabolite, 8-alpha-hydroxy-n-propyl-delta-9-THC, was not observed, even though it was a prominent metabolite from delta-9-THC itself. Hydroxylation occurred in the side-chain at C(2'). PMID:2839261

Brown, N K; Harvey, D J

1988-04-01

51

Poly(5-((2-trimethylsilyl-2-propyl)oxycarbonyl)-norbornene- co-maleic anhydride) for 193-nm lithography  

Microsoft Academic Search

A copolymer of 5-((2-trimethylsilyl-2-propyl)oxycarbonyl)-norbornene and maleic anhydride) was synthesized and evaluated as a chemically amplified resist for ArF lithography. The polymer has excellent transmittance at 193nm and possesses good thermal stability up to 195°C, whereas in the presence of an acid the cleavage of the 2-trimethylsilyl-2-propyl ester group begins at 76°C in a catalytic manner. The 0.18?m line and space

J.-B Kim; J.-J Lee; J.-S Kang

2000-01-01

52

Poly(2-trimethylsilyl-2-propyl methacrylate-co- ?-butyrolactone-2-yl methacrylate) for ArF lithography  

Microsoft Academic Search

Poly(2-trimethylsilyl-2-propyl methacrylate-co-?-butyrolactone-2-yl methacrylate) was synthesized and evaluated as a chemically amplified resist for ArF lithography. The polymer has excellent transmittance at 248nm and also has a good transmittance at 193nm. In addition, the polymer possesses good thermal stability up to 200°C, whereas in the presence of an acid the cleavage of the 2-trimethylsilyl-2-propyl ester group begins at about 80°C in

J.-B. Kim; H. Kim; S.-H. Lee; J.-T. Moon

1999-01-01

53

21 CFR 573.880 - Normal propyl alcohol.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

54

21 CFR 573.880 - Normal propyl alcohol.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

55

7-{4-[(1,3-Benzodioxol-5-yl)meth-yl]piperazin-1-yl}-1-cyclo-propyl-6-fluoro-4-oxo-1,4-dihydro-quinoline-3-carb-oxy-lic acid  

PubMed Central

In the title structure, C25H24FN3O5, a strong intra­molecular O—H?O hydrogen bond is present between the carb­oxy group at the 3-position and the carbonyl group at the 4-position. In the crystal, mol­ecules are held together by weak C—H?O, C—H?F and ?–? [centroid–centroid distance 3.6080?(8)?Å] inter­actions. The 1,4-dihydro­quinoline ring and cyclo­propyl group are not in the same plane, making an inter­planar angle of 57.52?(8)°.

Wang, Shuo; Shan, Guangzhi; Guo, Huiyuan; Liu, Mingliang

2012-01-01

56

Ecotoxicological effects of the antioxidant additive propyl gallate in five aquatic systems.  

PubMed

Propyl gallate is an antioxidant widely used in foods, cosmetics and pharmaceuticals. The occurrence and fate of additives in the aquatic environment is an emerging issue in environmental chemistry. To date, there is little available information about the adverse effects of propyl gallate on aquatic organisms. Therefore, the toxic effects were investigated, using five model systems from four trophic levels. The most sensitive system was the hepatoma fish cell line PLHC-1 according to total protein content, with an EC(50) of 10 microM and a NOAEL of 1 microM at 72 h, followed by the immobilization of Daphnia magna, the inhibition of bioluminescence of Vibrio fischeri, the salmonid fish cell line RTG-2 and the inhibition of the growth of Chlorella vulgaris. Although protein content, neutral red uptake, methylthiazol metabolization and acetylcholinesterase activity were reduced in PLHC-1 cells, stimulations were observed for lysosomal function, succinate dehydrogenase, glucose-6-phosphate dehydrogenase and ethoxyresorufin-O-deethylase activities. No changes were observed in metallothionein levels. The main morphological observations were the loss of cells and the induction of cell death mainly by necrosis but also by apoptosis. The protective and toxic effects of propyl gallate were evaluated. General antioxidants and calcium chelators did not modify the toxicity of propyl gallate, but an iron-dependent lipid peroxidation inhibitor gave 22% protection. The results also suggest that propyl gallate cytotoxicity is dependent on glutathione levels, which were modulated by malic acid diethyl ester and 2-oxothiazolidine-4-carboxylic acid. According to the results, propyl gallate should be classified as toxic to aquatic organisms. PMID:17382989

Zurita, Jorge L; Jos, Angeles; del Peso, Ana; Salguero, Manuel; López-Artíguez, Miguel; Repetto, Guillermo

2007-06-01

57

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

Code of Federal Regulations, 2013 CFR

...Amides, coco, N-[3-(dibutylamino)propyl], acrylates. 721.10192 Section...Amides, coco, N-[3-(dibutylamino)propyl], acrylates. (a) Chemical substance...amides, coco, N-[3-(dibutylamino)propyl], acrylates (PMN...

2013-07-01

58

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

Code of Federal Regulations, 2010 CFR

...Amides, coco, N-[3-(dibutylamino)propyl], acrylates. 721.10192 Section...Amides, coco, N-[3-(dibutylamino)propyl], acrylates. (a) Chemical substance...amides, coco, N-[3-(dibutylamino)propyl], acrylates (PMN...

2010-07-01

59

40 CFR 721.9501 - Silane, triethoxy[3-oxiranylmethoxy)propyl]-.  

Code of Federal Regulations, 2013 CFR

...Silane, triethoxy[3-oxiranylmethoxy)propyl]-. 721.9501 Section 721.9501...Silane, triethoxy[3-oxiranylmethoxy)propyl]-. (a) Chemical substance and...silane, triethoxy[3-oxiranylmethoxy)propyl]- (PMN P-01-781; CAS No....

2013-07-01

60

Dominant Lethal Assay for Bis-Dinitro-Propyl-Formal: Bis-Dinitro-Propyl-Acetal and Kerimide 601 Resin.  

National Technical Information Service (NTIS)

Bis-dinitro-propyl-formal:bis-dinitro-propyl-acetal (BDNPF:BDNPA) and kerimide 601 resin do not appear to be mutagenic at the doses utilized when introduced intragastrically either as an acute or chronic insult in vivo. It should be pointed out that the d...

J. S. Wilson D. M. Smith

1978-01-01

61

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

62

STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS : VIII. SENSITIZATION TO PICRIC ACID; SUBSIDIARY AGENTS AND MODE OF SENSITIZATION.  

PubMed

Sensitization of guinea pigs to picric acid was obtained by application of oil solutions to the skin, preferably on inflamed sites or by treatment with a compound of picric acid with n-butyl-p-aminobenzoate. The lesions obtained in sensitive animals on superficial administration bore resemblance to human eczema. It seems probable that picric acid sensitization is an instance where a substance does not sensitize directly but after conversion into a more reactive compound, a principle which should be of wider application to instances where the original substance does not readily form conjugates. PMID:19871030

Landsteiner, K; Di Somma, A A

1940-09-30

63

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

64

Propyl gallate, a free radical scavenger, counteracts the benefits of exogenously applied salicylic acid and aggravates the deleterious effects of the southern bean mosaic virus in Rhizobium-nodulated Phaseolus vulgaris plants  

Microsoft Academic Search

Infection of Rhizobium-nodulated Phaseolus vulgaris by the southern bean mosaic virus (SBMV) markedly decreased the growth and nodulation of plants. Exogenous applications of salicylic acid (SA) at concentrations ?10 ?M further decreased growth and nodulation of virus-infected (V) plants. Only SA concentration of 5 ?M in the solution improved the growth, nodulation, chlorophyll concentration and the catabolism of ureide in leaves of

Maria Luisa Izaguirre-Mayoral; Mario Jose Garrido

2010-01-01

65

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

66

Synthesis and properties of new soluble poly(amide–imide–imide)s based on tetraimide-dicarboxylic acid condensed from ODPA, BAPP and pABA, and various aromatic diamines  

Microsoft Academic Search

A new-type of tetraimide-dicarboxylic acid (I) was synthesized starting from ring-opening addition of p-aminobenzoic acid (p-ABA), 4,4?-oxydiphthalic anhydride (ODPA) and 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) at a 2:2:1 molar ratio in N-methyl-2-pyrrolidone (NMP), followed by cyclodehydration to the diacid I. A series of poly(amide–imide–imide)s (IIIa–i) with inherent viscosities of 0.82–1.20dlg?1 was prepared by triphenyl phosphite-activated polycondensation from the tetraimide-diacid (I) with various aromatic

Chin-Ping Yang; Ruei-Shin Chen; Chi-Shu Wei

2003-01-01

67

40 CFR 721.9500 - Silane, (1,1-dimethylethoxy) dimethoxy(2-methyl propyl)-.  

Code of Federal Regulations, 2013 CFR

... Silane, (1,1-dimethylethoxy) dimethoxy(2-methyl propyl)-. 721.9500 Section 721.9500 Protection of Environment... Silane, (1,1-dimethylethoxy) dimethoxy(2-methyl propyl)-. (a) Chemical substance and significant new uses...

2013-07-01

68

40 CFR 721.8225 - 2-Propenamide, N-[3-di- methyl-amino)propyl]-.  

Code of Federal Regulations, 2013 CFR

... false 2-Propenamide, N-[3-di- methyl-amino)propyl]-. 721.8225 Section 721.8225 Protection of Environment...8225 2-Propenamide, N -[3-di- methyl-amino)propyl]-. (a) Chemical substance and significant new uses...

2013-07-01

69

40 CFR 721.9501 - Silane, triethoxy[3-oxiranylmethoxy)propyl]-.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Silane, triethoxy[3-oxiranylmethoxy)propyl...Specific Chemical Substances § 721.9501 Silane, triethoxy[3-oxiranylmethoxy)propyl...The chemical substance identified as silane,...

2010-07-01

70

40 CFR 721.9501 - Silane, triethoxy[3-oxiranylmethoxy)propyl]-.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Silane, triethoxy[3-oxiranylmethoxy)propyl...Specific Chemical Substances § 721.9501 Silane, triethoxy[3-oxiranylmethoxy)propyl...The chemical substance identified as silane,...

2009-07-01

71

Voltammetric determination of butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate and tert-butylhydroquinone by use of chemometric approaches  

Microsoft Academic Search

The voltammetric behavior of synthetic food antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG) and tert-butylhydroquinone (TBHQ), at a glassy carbon electrode in solution of 0.1moll?1 perchloric acid containing 1% methanol has been investigated. The obtained linear sweep voltammograms (LSV) showed that all these four compounds have well-defined oxidation waves with peak potentials of 629, 818,

Yongnian Ni; Li Wang; Serge Kokot

2000-01-01

72

TRI-2 Propyl Phosphate-Lanthanide Nitrate Complexes  

SciTech Connect

Tri-2-propyl phosphase (T2PP) reacts with lanthanide nitrates to form two series of solid complexes. These complexes were characterized by elemental analyses. X-ray diffraction patterns showed a single structure for each series, and infrared spectra showed that both nitrate and T2PP ligand were coordinated with lanthanide ions. The relative stabilities of the different species are discussed.

McRae, J.R.

2001-08-29

73

Metabolism of (+/-)-N-(n-propyl) amphetamine by Cunninghamella echinulata.  

PubMed Central

(+/-)-N-(n-propyl) amphetamine (I), a secondary amine, was readily metabolized by Cumminghamella echinulata. The products included known C- and N-oxygenated mammalian metabolites as well as N-acetylamphetamine and were identified by gas chromatography and mass spectrometry.

Coutts, R T; Foster, B C; Jones, G R; Myers, G E

1979-01-01

74

40 CFR 721.10191 - Amides, coco, N-[3-(dibutylamino)propyl].  

Code of Federal Regulations, 2013 CFR

...Amides, coco, N-[3-(dibutylamino)propyl]. 721.10191 Section 721.10191...Amides, coco, N-[3-(dibutylamino)propyl]. (a) Chemical substance and significant...amides, coco, N-[3-(dibutylamino)propyl] (PMN P-06-262; CAS No....

2013-07-01

75

Synthesis of O -[2-hydroxy-3-(vinyloxy)propyl]oximes and O -[(2-methyl-1,3-dioxolan-4-yl)methyl]oximes  

Microsoft Academic Search

By oximes reaction with glycidyl vinyl ether O-[2-hydroxy-3-(vinyloxy)propyl]oximes of ketones and acetaldehyde were synthesized in 54–72% yield, and by acid catalysis\\u000a the compounds were converted into O-[(2-methyl-1,3-dioxolan-4-yl)methyl]oximes in 61–88% yield.

B. F. Kukharev; V. K. Stankevich; G. R. Klimenko; A. N. Shaposhnikova

2007-01-01

76

Geno- and cytotoxicity of propyl gallate food additive.  

PubMed

Abstract Synthetic phenolic food additives, such as propyl 3,4,5-trihydroxybenzoate (propyl galate; PG), have been used as an antioxidant in the food industry to prevent oils from spoiling. Their toxicity is one of the challengeable issues resulting from the widespread usage of them in food-related industrials. In this study, we investigated the anticell proliferation effects of PG on A549 lung cancer cells. The result showed that PG dose and time dependently decreased the growth of A549 cells with an half-maximal inhibitory concentration of approximately 1?×?10(-3) and 5?×?10(-4?)M of PG at 48 and 72 hours, respectively. In addition, DNA strand breaks have been observed through the comet assay technique. Also, morphology of 4',6-diamidino-2-phenylindole (DAPI)-stained cells showed an obvious fragmentation in the chromatin and DNA rings within the nucleus of PG-treated cells, and, finally, flow cytometry analyses of the cells confirmed DAPI staining assay and determined early and late apoptosis in treated cells. PMID:24160552

Hamishehkar, Hamed; Khani, Sajjad; Kashanian, Soheila; Ezzati Nazhad Dolatabadi, Jafar; Eskandani, Morteza

2014-07-01

77

Rates of reaction of propyl radicals with molecular oxygen  

SciTech Connect

The rates of reaction of 1-propyl and 2-propyl radicals with O/sub 2/ have been measured in the gas phase at room temperature. The rate constants are k/sub 1/(1-C/sub 3/H/sub 7/+O/sub 2/) = (5.5 +/- 0.9) x 10/sup -12/ cm/sup 3/ molecule/sup -1/ s/sup -1/ and k/sub 2/(2-C/sub 3/H/sub 7/+O/sub 2/) = (14.1 +/- 2.4) x 10/sup -12/ cm/sup 3/ molecule/sup -1/ s/sup -1/. Limited pressure studies suggest that both of these reactions are at or near their high-pressure limits at pressures of a few torr. The logarithms of these and previously measured rate constants show an excellent correlation with the ionization potential of the alkyl radical. Adiabatic channel model calculations have been carried out for these reactions with various long-range potential functions. It is concluded that some mixing of the charge-transfer surface (R/sup +/ + O/sub 2//sup -/) into the neutral surface (R + O/sub 2/) is responsible for the correlation of log (k) with ionization potential.

Ruiz, R.P.; Bayes, K.D.

1984-06-07

78

Ecotoxicological effects of the antioxidant additive propyl gallate in five aquatic systems  

Microsoft Academic Search

Propyl gallate is an antioxidant widely used in foods, cosmetics and pharmaceuticals. The occurrence and fate of additives in the aquatic environment is an emerging issue in environmental chemistry. To date, there is little available information about the adverse effects of propyl gallate on aquatic organisms. Therefore, the toxic effects were investigated, using five model systems from four trophic levels.

Jorge L. Zurita; Ángeles Jos; Ana del Peso; Manuel Salguero; Miguel López-Artíguez; Guillermo Repetto

2007-01-01

79

Determination of enantiomeric purity of the new D-2 dopamine agonist 2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin (N-0437) by reversed-phase high-performance liquid chromatography after pre-column derivatization with D(+)-glucuronic acid.  

PubMed

This paper describes an enzymic derivatization procedure that allows accurate determination of very small amounts of enantiomeric impurities in the D-2 dopamine agonist 2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin (N-0437). After pre-column glucuronidation of the individual enantiomers, two diastereoisomers were formed which were separated by reversed-phase high-performance liquid chromatography. An enantiomeric purity of 99.84% was calculated for the (-)-enantiomer, against 99.89% for the (+)-enantiomer. The assay was validated by spiking 1% of the (-)-enantiomer in the (+)-enantiomer. A high accuracy (error 4.5%) and precision (coefficient of variation 2.9%, n = 5) of the method were established. PMID:2715255

Gerding, T K; Drenth, B F; Van de Grampel, V J; Niemeijer, N R; De Zeeuw, R A; Tepper, P G; Horn, A S

1989-01-27

80

The N-acetylation of arsanilic acid In vitro by mammalian enzymes.  

PubMed

The N-acetylation of arsanilic acid was assayed in vitro by modifying a literature method for acetylation of p-aminobenzoic acid. Conditions included final concentrations of 1.0 mM dithiothreitol, 1.0 mM EDTA, 0.45 mM acetyl coenzyme A, an acetyl coenzyme A regenerating system using bacterial phosphotransacetylase and acetyl phosphate, 5.0 mM arsanilate substrate, and 25 mM sodium/potassium phosphate buffer, pH 7.4, in a total volume of 0.5 ml. Incubation was at 37 degrees C, with 0.5- to 2-mg N-acetyltransferase enzyme protein from a preparation of guinea pig liver. The reaction was terminated by heat precipitation. The resulting supernatant was put through a 4 mm 0.45 microm polysulfone membrane syringe filter. The filtrate could then be injected directly onto the HPLC. With arsanilic acid as substrate, the product N-acetylarsanilic acid (NAA) was identified by its retention time (33 min) in the HPLC system of the laboratory. The 33-min fraction collected from the HPLC was scanned and gave the characteristic UV spectrum of NAA, with peaks at 203 and 256 nm. In addition, the product comigrated in the HPLC system with standard NAA. Under comparable assay conditions, the N-acetylation of arsanilate by the guinea pig enzyme preparation is about 24% the rate of that of the model substrate p-aminobenzoic acid. Typical activity for arsanilate acetylation was 0.5 nmol/min/mg enzyme protein. Using the same assay system and HPLC detection method, the supernatant from bacterial lysates containing recombinant human N-acetyltransferase 1 exhibited acetylation activity toward arsanilate of 720 nmol/min/mg enzyme protein. PMID:10725319

Bayse, G S; Jinadu, L A; Shaw, K L; Wiley, K L

2000-04-01

81

Synthesis, characterization and electrochromic properties of conducting copolymers of 2,3-bis-[(3-thienylcarbonyl)oxy]propyl 3-thiophene carboxylate with thiophene and pyrrole  

Microsoft Academic Search

2,3-bis-[(3-thienylcarbonyl)oxy]propyl 3-thiophene carboxylate (TOPT) was synthesized via the reaction of 3-thionylcarboxylic acid with glycerol, and electrochemically polymerized either with thiophene and pyrrole by using tetrabutylammonium tetrafluoroborate (TBAFB) as the supporting electrolyte in acetonitrile (AN). Characterization of the resulting copolymers was performed via cyclic voltammetry, FTIR, thermal gravimetry analysis (TGA), and scanning electron microscopy (SEM). Electrical conductivities were measured by the

U. Bulut; L. Toppare; F. Y?lmaz; Y. Ya?c?

2004-01-01

82

The addition of molecular oxygen to hydroperoxy-propyl radicals  

SciTech Connect

The addition of hydroperoxy-alkyl radicals to molecular oxygen is an important process leading to chain branching in the low temperature oxidation of paraffins and at conditions related to autoignition and engine knock. The product channels for the addition of hydroperoxy-propyl radicals to molecular oxygen were estimated using bimolecular QRRK analysis and transition state theory. Thermochemistry of all the relevant species was estimated using group additivity. The main products at 1--15 atm are stabilization, alkyl carbonyl + OH, and in some cases an olefinic hydroperoxide + HO{sub 2}. Product channels for each of the three hydroperoxy-alkyl isomers were analyzed and rate expressions for each channel were calculated for a series of pressures over a temperature range of 600--1600 K.

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

1993-10-01

83

Density functional study on ionic liquid of 1-propyl-4,5-dibromo-3-methylimidazolium bromide  

NASA Astrophysics Data System (ADS)

The density functional method and DNP basis set were employed to study 1-pair, 2-pair, and 3-pair of cation-anion interactions of 1-propyl-4,5-dibromo-3-methylimidazolium bromides. The calculated results reveal that H 2 atoms of 1-propyl-4,5-dibromo-3-methylimidazolium form hydrogen bondings with Br -. The natural bond orbital (NBO) and atoms in molecules (AIM) analyzes show that halogen bondings between Br - anion and imidazolium ring substituted bromine atoms were formed in the gas phase, in agreement with the crystal phase of 1-propyl-4,5-dibromo-3-methylimidazolium bromide which is governed by both hydrogen bondings and halogen bondings.

Lü, Renqing; Wang, Shutao; Lu, Yukun

2011-03-01

84

Dialkyl (3-(1-silatranyl)propyl) phosphoramidates and their thionic and thiolic analogs  

SciTech Connect

The reactions of (3-aminopropyl)triethoxysilane with dialkyl phosphorochloridates and their thionic and thiolic analogs lead to the corresponding dialkyl (3-(triethoxysilyl)propyl)phosphoramidates and their thio analogs. Methods were developed for the synthesis of dialkyl (3-(1-silatranyl)propyl)phosphoramidates and their thionic and thiolic analogs by the transetherification of the corresponding dialkyl (3-(triethoxysilyl)propyl)phosphoramidates and their thio analogs with triethanolamine. The reactions and structures of the products are confirmed by IR and full NMR spectroscopy using hydrogen 1, phosphorus 31, carbon 13, and silicon 29 chemical shift, coupling constant, and line structure analysis.

Voronkov, M.G.; Kudyakov, N.M.; Albanov, A.I.

1986-11-10

85

Production of propyl gallate in nonaqueous medium using cell-associated tannase of Bacillus massiliensis: effect of various parameters and statistical optimization.  

PubMed

Enzymatic synthesis of propyl gallate in an organic solvent was studied using cell-associated tannase (E.C. 3.1.1.20) of Bacillus massiliensis. Lyophilized biomass showing tannase activity was used as a biocatalyst. The influence of buffer pH and strength, water activity, temperature, biocatalyst loading, gallic acid concentration, and 1-propanol concentration was studied by the one-factor-at-a-time method. Subsequently, response surface methodology was applied based on a central composite design to determine the effects of three independent variables (biocatalyst loading, gallic acid concentration, and 1-propanol concentration) and their mutual interactions. A total of 20 experiments were conducted, and a statistical model was developed, which predicted the maximum propyl gallate yield of 20.28 ?g/mL in the reaction mixture comprising 40.4 mg biocatalyst, 0.4 mM gallic acid, and 6.52 % (v/v) 1-propanol in 9.5 mL benzene at 30°C. The subsequent verification experiments established the validity of the model. Under optimal conditions, 25% conversion of gallic acid to propyl gallate was achieved on a molar basis. The absence of the need for enzyme purification and subsequent immobilization steps and good conversion efficiency makes this enzyme system an interesting one. Reports on the applications of bacterial whole cell systems for synthetic reactions in organic solvents are scarce, and perhaps this is the first report on bacterial cell-associated tannase-mediated esterification in a nonaqueous medium. PMID:23600575

Aithal, Mahesh; Belur, Prasanna D

2013-01-01

86

A novel inhibitor for Fe-type nitrile hydratase: 2-cyano-2-propyl hydroperoxide.  

PubMed

Nitrile hydratase (NHase) is a non-heme iron or non-corrin cobalt enzyme having two post-translationally modified ligand residues, cysteine-sulfinic acid (alphaCys112-SO(2)H) and -sulfenic acid (alphaCys114-SOH). We studied the interaction between Fe-type NHase and isobutyronitrile (iso-BN) which had been reported as a competitive inhibitor with a K(i) value of 5 microM. From detailed kinetic studies of the inhibitory effect of iso-BN on Fe-type NHase, we found that authentic iso-BN was hydrated normally and that the impurity present in commercially available iso-BN inhibited NHase activity strongly. The inhibitory compound induced significant changes in the UV-vis absorption spectrum of NHase, suggesting its interaction with the iron center. This compound was purified by using reversed-phase HPLC and identified as 2-cyano-2-propyl hydroperoxide (Cpx) by (1)H and PFG-HMBC NMR spectroscopy. Upon addition of a stoichiometric amount of Cpx, NHase was irreversibly inactivated, probably by the oxidation of alphaCys114-SOH to Cys-SO(2)H. This result suggests that the -SOH structure of alphaCys114 is essential for the catalytic activity. The oxygen atom in Cys-SO(2)H is confirmed to come from the solvent H(2)O. The oxidized NHase was found to induce the UV-vis absorption spectral changes by addition of Cpx, suggesting that Cpx strongly interacted with iron(III) in the oxidized NHase to form a stable complex. Thus, Cpx functions as a novel irreversible inhibitor for NHase. PMID:13129355

Tsujimura, Masanari; Odaka, Masafumi; Nakayama, Hiroshi; Dohmae, Naoshi; Koshino, Hiroyuki; Asami, Tadao; Hoshino, Mikio; Takio, Koji; Yoshida, Shigeo; Maeda, Mizuo; Endo, Isao

2003-09-24

87

Bromide and N -acetyl- S -( n -propyl)- l -cysteine in urine from workers exposed to 1-bromopropane solvents from vapor degreasing or adhesive manufacturing  

Microsoft Academic Search

Objectives  1-Bromopropane (1-BP) is an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives,\\u000a and cleaning solvents. There is concern that 1-BP may be a reproductive and neurological toxicant. Mercapturic acid conjugates\\u000a are excreted in urine from 1-BP metabolism involving debromination. The main objectives were to evaluate urinary bromide [Br(?)] and N-acetyl-S-(n-propyl)-l-cysteine (AcPrCys) for assessing 1-BP

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

2010-01-01

88

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

89

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

Microsoft Academic Search

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)Å3. 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

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

2003-01-01

90

Plasma clearance in the rat of a furan dicarboxylic acid which accumulates in uremia  

Microsoft Academic Search

Plasma clearance in the rat of a furan dicarboxylic acid which accumulates in uremia. The furan dicarboxylic acid 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (5-propyl FPA) accumulates in the plasma of patients with chronic renal failure and has been implicated in several aspects of the uremic syndrome: the defective binding of organic acids in uremic plasma, inhibition of active tubular secretion, anemia and the

Michael G Costigan; W Edward Lindup

1996-01-01

91

Synthesis and Characterization of Mixed Substituent P-n-Propyl-N-trimethylphosphoranimines  

SciTech Connect

One approach to the synthesis of polyphosphazenes is the condensation polymerization of phosphoranimines. In this work, several novel P-n-propyl-N-trimethylsilylphosphoranimines have been synthesized and characterized. Modifications to the literature synthetic routes were required to obtain the precursor phosphines. The N-trimethylsilylphosphoranimines were obtained though oxidation of the phosphine with bromine and then subsequent nucleophilic displacement using lithium phenoxide. These phosphoranimines were stable for long periods of time under dry inert conditions. NMR analyses revealed complex splitting patterns beyond typical coupling due to the stereocenter at phosphorus. We report several approaches to the n-propyl containing phosphines

Klaehn, John Ray; Luther, Thomas Alan; Harrup, Mason Kurt; Stewart, Frederick Forrest

2003-07-01

92

The occurrence of furan fatty acids in Isochrysis sp. and Phaeodactylum tricornutum.  

PubMed

Two algae species with a fundamentally different fatty acid composition were investigated for their furan fatty acid (F-acid) content. Isochrysis sp. contains different F-acids with a pentyl side chain in alpha'-position of the furan ring. In consideration of its fatty acid composition which is predominated by compounds with a C-18 chain, this result supports the assumption that pentyl-F-acids derive from linoleic acid. In contrast, only F-acids with propyl side chain were found in Phaeodactylum tricornutum. The low content of C-18 fatty acids in this diatomae contradicts the previous hypothesis that linolenic acid is the precursor of propyl-F-acids. But the presence of (n - 4) unsaturated fatty acids with 16 carbon atoms in Phaeodactylum tricornutum suggests that propyl-F-acids are synthesized from 9,12-hexadecadienoic acid in a very similar biogenetic pathway than pentyl-F-acids. PMID:8443233

Batna, A; Scheinkönig, J; Spiteller, G

1993-02-24

93

Vapor-liquid equilibria for the mixtures ether + 2-butanol and + propyl acetate at 101. 3 kPa  

SciTech Connect

Vapor-liquid equilibrium data at 101.3 kPa pressure for the systems 2-butanol + dibutyl ether, 2-butanol + tetrahydrofuran, propyl acetate + dibutyl ether, and propyl acetate + tetrahydrofuran are reported. The experimental data were well correlated by different thermodynamic equations. The experimental data have also been compared with those predicted by the UNIFAC group contribution method.

Benito, G.G.; Carton, A.; Uruena, M.A. (Univ. of Valladolid (Spain). Dept. of Chemical Engineering)

1994-04-01

94

Disposition in rats of N-pyridinium-propyl-cyclam, N-triethylammonium-propyl-cyclam, and N-[Triethylammonium]-3-propyl-[15]ane-N5, potential cartilage imaging agents.  

PubMed

Quaternary ammonium compounds are known to highly concentrate in articular cartilages after i.v. administration. This property was used to synthesize new potential radiodiagnostic agents for joint imaging. Pharmacokinetic study was performed in rats for three new compounds: N-pyridinium-propyl-cyclam (NPPC), N-triethylammonium-propyl-cyclam (NTPC), and N-[triethylammonium]-3-propyl-[15]ane-N5 (NTP 15-5). After i.v. administration, [(3)H]NPPC and [(3)H]NTPC highly and rapidly concentrated in articular cartilage, this uptake being followed by a single exponential decrease with half-lives of, respectively, 75 and 82 min. Except cartilage, only the kidney was highly labeled. After complexation of (99m)Tc by NPPC, NTPC, and NTP 15-5, only (99m)Tc-NTP 15-5 exhibited a high affinity for cartilage. On the other hand, the pharmacokinetic behavior of (99m)Tc-NTPC and (99m)Tc-NPPC was very different from those of their (3)H-labeled analogs. Concentration in cartilaginous tissues was strongly diminished, and liver and bone were highly labeled. For all labeled species, the major route of excretion was urine, and HPLC analysis showed that [(3)H]NTPC and [(3)H]NPPC were excreted under their unchanged form. On the other hand, no (99m)Tc-NTPC and (99m)Tc-NPPC were found in the urine, the radioactivity being mainly due to free technetium, contrary to (99m)Tc-NTP 15-5, which was excreted in the urine under the complexed form. These data can explain the striking differences observed between the three (99m)Tc-labeled molecules, the lack of concentration of (99m)Tc-NTPC, and (99m)Tc-NPPC in cartilages in comparison with their (3)H-labeled analogs due to an instability in vivo of these technetiated complexes. PMID:10725310

Maurizis, J C; Rapp, M; Nicolas, C; Ollier, M; Verny, M; Madelmont, J C

2000-04-01

95

Pathway and kinetic analysis on the propyl radical + 02 reaction system  

SciTech Connect

In this study of the reaction of alkyl radicals with molecular oxygen, we analyze the propyl + 02 reaction system using thermochemical kinetics, Transition State Theory (TST), molecular thermodynamic properties, quantum Kassel analysis (quantum RRK) for k(E) and modified strong collision analysis for fall off. Cyclic transition states for both hydrogen transfer and the H02 concerted elimination from propylperoxy are calculated using semi-empirical (MOPAC PM3) calculations [8] in addition to transition states for H02 elimination and epoxide formation from hydroperoxy-isopropyl. Computed rate constants for propyl + 02 are compared to the values of Gulati and Walker who measured the rate constants at 50 torr and over a temperature range of 653 to 773 K. Computed rate constants are also used in a detailed chemical kinetic mechanism and compared to the n- propyl + 02 data of Slagle. They measured the rate of disappearance of n-propyl by reaction with 02 over a temperature range of 297 to 635 K and a pressure range of 0.4 to 7 Torr, as well as the fall off data of the Kaiser and Wallington.

Bozzelli, J.W.; Pitz, W.J.

1997-05-01

96

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

97

Rotational spectra of methyl ethyl and methyl propyl nitrosamines. Conformational assignment, internal rotation and quadrupole coupling  

NASA Astrophysics Data System (ADS)

A structural determination of two carcinogenic nitrosamines, methyl ethyl and methyl propyl nitrosamine, was performed. Microwave spectra were gathered from both a Stark cell spectrometer and a pulsed jet Fabry-Perot Fourier transform microwave spectrometer. Each rotational transition is split into quadrupole hyperfine components by two nitrogen nuclei. This quadrupole pattern is doubled by a low barrier methyl rotor which produces resolvable A and E states. Rotational spectra were assigned for one conformer of methyl ethyl nitrosamine and two conformers of methyl propyl nitrosamine. The lowest energy conformers of each compound, according to empirical force field calculations, were assigned. The structure found for methyl ethyl nitrosamine has the nitrosyl oxygen on the methyl side with the terminal methyl group of the ethyl chain in the gauche position (OMG). Both conformers of methyl propyl nitrosamine have the same skeletal structure as the methyl ethyl compound; one conformer has the terminal methyl of the propyl group in the anti position (OMGA) while the other conformer has this methyl in the gauche position (OMGG -). Rotational constants and quadrupole coupling constants are reported for each assigned species. A barrier to internal rotation of the N-methyl group in each compound is also reported.

Walker, A. R. Hight; Lou, Qi; Bohn, Robert K.; Novick, Stewart E.

1995-02-01

98

STUDIES ON THE MISCIBILITY OF POLY(2-HYDROXYETHYLMETHACRYLATE) AND HYDRODY PROPYL METHYL CELLULOSE BLENDS  

Microsoft Academic Search

Miscibility characteristics of poly[2–hydroxyethylmethacrylate] (PHEMA) and hydroxy propyl methyl cellulose (HPMC) have been investigated by solution viscometry, ultrasonic and differential scanning calorimetric (DSC) methods. The interaction parameters were obtained using the viscosity data. Ultrasonic velocity and adiabatic compressibilities versus blend composition have been plotted and are found to be linear. Variation of glass transition temperature (Tg) with composition follows the

K. Prashantha; K. Vasanth Kumar Pai; B. S. Sherigara

2004-01-01

99

Methyl 3-(cyclo-propyl-meth-oxy)-4-hy-droxy-benzoate  

PubMed Central

In the title compound, C12H14O4, the dihedral angle between the benzene ring and the cyclo­propyl ring is 60.3?(4)°. In the crystal structure, mol­ecules are linked by inter­molecular O—H?O hydrogen bonds into chains running parallel to [101].

Hou, Jing-Jing; Cheng, Xian-Chao; Wang, Run-Ling; Wang, Shu-Qing

2010-01-01

100

Antifungal effect of different methyl and propyl paraben mixtures on the treatment of paper biodeterioration  

Microsoft Academic Search

With many important artistic works and documents made of paper, and thus susceptible to biodeterioration by fungi, research is required in an effort to replace toxic chemical products with other more benign ones. In this work the antifungal effect of methyl and propyl paraben mixtures at different concentrations was evaluated. The fungi used in the experiments were a Cladosporium species

Eva Raquel Neves; Stephan Schäfer; Alan Phillips; João Canejo; Maria Filomena Macedo

2009-01-01

101

No-carrier-added carbon-11-labeled sn-1,2- and sn-1,3-diacylglycerols by (11C)propyl ketene method  

SciTech Connect

This article describes the preparation of sn-1,2-(11C)diacylglycerols and sn-1,3-(11C)diacylglycerols by a no-carrier-added reaction based on a labeling method using (1-11C)propyl ketene, which is one of the most potent acylating agents. (1-11C)Propyl ketene was produced by pyrolytic decomposition of (1-11C)butyric acid and was trapped in pyridine containing L-alpha-palmitoyl-lysophosphatidylcholine, producing L-alpha-palmitoyl-2-(1-11C)butyryl-sn-glycero-3-phosphorylcholine. The authors adopted an enzymatic reaction to remove the phosphorylcholine, in which L-alpha-palmitoyl-2-(1-11C)butyryl-sn-glycero-3-phosphorylcholine was incubated with phospholipase C, hydrolyzing to produce 1-palmitoyl-sn-2-(1-11C)butyrylglycerol. Total synthesis time was about 50 minutes and the specific activity was estimated at 93 GBq/mumol (2.5 Ci/mumol) at end of synthesis. Radiochemical yield was 3.8% based on the trapped 11CO2. sn-1,3-(11C)Diacylglycerol was also synthesized by (1-11C)propyl ketene reaction with 1-palmitoyl-sn-glycerol in a single procedure. The regional brain tissue radioactivities obtained in sn-1,2-(11C)diacylglycerol were higher than those of sn-1,3-(11C)diacylglycerol, and the regional values varied widely. In autoradiography of brain slices from conscious rats, sn-1,2-(11C)diacylglycerol incorporation sites were discretely localized, especially in the amygdala, cerebral cortex, and hippocampus, suggesting that intensive neuronal processing occurred in these areas on the basis of phosphatidylinositol turnover.

Imahori, Y.; Fujii, R.; Ueda, S.; Ido, T.; Nishino, H.; Moriyama, Y.; Yamamoto, Y.L.; Nakahashi, H. (Kyoto Prefectural University of Medicine (Japan))

1991-08-01

102

Reactions of OH and Cl with isopropyl formate, isobutyl formate, n-propyl isobutyrate and isopropyl isobutyrate  

NASA Astrophysics Data System (ADS)

The rate coefficients for the reactions of OH with isopropyl formate, isobutyl formate, n-propyl isobutyrate and isopropyl isobutyrate have been determined using both absolute and relative methods. The relative rate method has been also used to measure the room temperature rate coefficient for the reaction of Cl with the same esters. In addition, a series of runs conducted on the OH-initiated oxidation of isopropyl formate, isobutyl formate and n-propyl isobutyrate showed the formation of acetone from the three reactions. The formation of propanal was also observed for n-propyl isobutyrate.

Zhang, Y. J.; Liang, P.; Jiang, Z. H.; Cazaunau, M.; Daële, V.; Mu, Y. J.; Mellouki, A.

2014-05-01

103

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

104

The action of tetra-n-propyldiborane on n-butyl vinyl ether and esters of allyboric and allylthioboric acids  

Microsoft Academic Search

1.When tetra-n-propyldiborane acts on n-butyl vinyl ether, di-n-propyl-(2-n-butoxyethyl)boron is formed, which is converted at room temperature with evolution of ethylene to the n-butyl ester of di-n-propylboric acid.2.Tetra-n-propyldiborane adds to esters of allyl- and allylthioboric acid with the formation of unstable din-propyl-(2-methoxyborylpropyl) boron or di-n-propyl-(2-methylmercaptopropyl)boron, which decompose to esters of di-n-propylboric or di-n-propylthioboric acids and polymers (-CH2- CH2-CH2B-X)n.

B. M. Mikhailov; E. N. Safonova

1965-01-01

105

Thermal conversion of 2-propyl iodide on O/Ni(100): Changes in produce distribution with varying oxygen coverages  

SciTech Connect

The oxidation of 2-propyl iodide on oxygen-covered Ni(100) surfaces has been studied with temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and ion-scattering spectroscopy (ISS). The product distribution was strongly dependent on oxygen preexposure. XP I 3d core-level spectra indicate that the adsorption of 2-propyl iodide below 100 K is molecular, and ISS data strongly suggest preferential bonding to Ni sites, Annealing the 2-propyl iodide adsorbed on O/Ni(100) surfaces between 120 to 200 K generates 2-propyl groups on the nickel sites via dissociation of the C-I bond, the same as on the clean surface. 48 refs., 10 figs.

Gleason, N.R.; Zaera, F. [Univ. of California, Riverside, CA (United States)] [Univ. of California, Riverside, CA (United States)

1997-07-01

106

meso-1-{[2-(Propyl-1-sulfin-yl)eth-yl]sulfin-yl}propane  

PubMed Central

The title mol­ecule, C8H18O2S2, is disposed about a centre of inversion implying an anti-disposition of the sulfinyl-O atoms; the terminal n-propyl group has an extended conformation. The crystal packing is dominated by C—H?O inter­actions, which lead to the formation of supra­molecular arrays in the bc plane.

Wardell, Solange M. S. V.; Wardell, James L.; de Lima, Geraldo M.; Tiekink, Edward R. T.

2010-01-01

107

Laboratory Evaluation of Drop-in Solvent Alternatives to n-Propyl Bromide for Vapor Degreasing  

NASA Technical Reports Server (NTRS)

Based on this limited laboratory study, solvent blends of trans-1,2 dichloroethylene with HFEs, HFCs, or PFCs appear to be viable alternatives to n-propyl bromide for vapor degreasing. The lower boiling points of these blends may lead to greater solvent loss during use. Additional factors must be considered when selecting a solvent substitute, including stability over time, VOC, GWP, toxicity, and business considerations.

Mitchell, Mark A.; Lowrey, Nikki M.

2012-01-01

108

Role of redox signaling regulation in propyl gallate-induced apoptosis of human leukemia cells  

Microsoft Academic Search

Propyl gallate (PG) is a synthetic antioxidant that has been used in processed food and medicinal preparations. The anti-cancer effect of PG in leukemia is unclear. In the present study, we demonstrate that PG reduced cell viability in THP-1, Jurkat, and HL-60 leukemia cells and induced apoptosis in THP-1 cells. PG activated caspases 3, 8, and 9 and increased the

Ching-Hsein Chen; Wan-Chen Lin; Chien-Neng Kuo; Fung-Jou Lu

2011-01-01

109

Optimization and application of microwave-assisted acid hydrolysis for rapid quantification of protein oxidation markers using LC-MS.  

PubMed

Simple and efficient microwave-assisted acid hydrolysis (MAAH) of proteins was used for rapid quantification of ?-aminoadipic semialdehyde (AAS) and ?-glutamic semialdehyde (GGS) as major protein oxidation markers. The precursor amino acid residues corresponding to AAS and GGS in oxidized proteins were derivatized by reductive amination with sodium cyanoborohydride (NaCNBH(3)) and p-aminobenzoic acid (ABA) followed by MAAH to generate the marker derivatives AAS-ABA and GGS-ABA. The quantification was performed using electrospray ionization liquid chromatography-mass spectrometry (ESI LC-MS). The important parameters for hydrolysis were optimized, which include the temperature, the reaction time, the acid concentration and volume as well as the microwave power. Compared to the conventional acid hydrolysis of 18-24h using 6-12 M HCl at 110°C applied commonly in the literature and also in this work, MAAH of proteins can be completed as fast as in only 2-10 min and, additionally, with a 3-5 times higher yield of the final derivatization products. Furthermore, a better agreement between the ratio of the detected derivatization products and the theoretical yields from the studied protein has also been achieved, which indicates that MAAH may serve as a more reliable method of acid hydrolysis for this purpose than that with conventional thermal heating. The MAAH method is demonstrated to be a time-saving, reproducible and efficient technique for studying AAS and GGS as protein oxidation markers using LC-MS. PMID:21872027

Afiuni-Zadeh, Somaieh; Guo, Xinghua; Azimi, Gholamhassan; Lankmayr, Ernst

2011-09-30

110

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

111

The common occurrence of furan fatty acids in plants.  

PubMed

The observation that F-acids (1) occur in rat chow initiated a search for F-acids in human diet. We observed that the amount of F-acids with a pentyl side chain in alpha-position taken up with a one-day diet correlates well with the amount of excreted degradation products, the pentyl urofuran acids (2), (3) and (4). Therefore it can be concluded that F-acids with a pentyl side chain are not produced in the human body but are introduced through the diet. The origin of F-acids carrying an alpha-propyl side chain is less clear. The amount of propyl-urofuran acids (2) and (3) excreted in urine was found in one case out of three to be five times higher than the amount of F-acids carrying a propyl group in alpha-position taken up by the diet. Therefore, it can presently not be excluded that a portion of the propyl F-acids is produced by the body. F-acids found in human food are mainly introduced into the body by vegetables and fruits. F-acids were found also in birch leaves in considerable amounts, as well as in grasses, dandelion and clover leaves. Thus, we can conclude that F-acids are common constituents of plants. PMID:2755307

Hannemann, K; Puchta, V; Simon, E; Ziegler, H; Ziegler, G; Spiteller, G

1989-04-01

112

rac-2-Phenyl-1-[(2,4,6-triiso-propyl-benzene)-sulfon-yl]aziridine.  

PubMed

In the title compound, C23H31NO2S, the geometry of the triiso-propyl-phenyl 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-toluene-sulfonyl-aziridine [Zhu et al. (2006 ?). Acta Cryst. E62, o1507-o1508]. ?-? inter-actions between adjacent benzene rings [centroid-centroid distance = 3.7928?(11)?Å] and are observed. PMID:24764875

Golz, Christopher; Preut, Hans; Strohmann, Carsten

2014-02-01

113

Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite  

NASA Technical Reports Server (NTRS)

Homologous series of alkyl phosphonic acids and alkyl sulfonic acids, along with inorganic orthophosphate and sulfate, are identified in water extracts of the Murchison meteorite after conversion to their t-butyl dimethylsilyl derivatives. The methyl, ethyl, propyl, and butyl compounds are observed in both series. Five of the eight possible alkyl phosphonic acids and seven of the eight possible alkyl sulfonic acids through C4 are 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 the alkyl sulfonic acid series, and from 9 nmol/gram in the alkyl phosphonic acid series.

Cooper, George W.; Onwo, Wilfred M.; Cronin, John R.

1992-01-01

114

1,2:5,6-Di-O-iso-propyl-idene-3-C-methyl-?-d-allo-furan-ose  

PubMed Central

The title carbohydrate, C13H22O6, is a derivative of d-glycose, in which the furan­osidic and iso­propyl­idene rings are in twisted conformations. The mean plane of the furan­osidic ring makes a dihedral angle of 70.32?(18)° with the mean plane of the fused iso­propyl­idene ring. The methyl groups in the other iso­propyl­idene ring are disordered over two sets of sites, with an occupancy ratio of 0.74?(6):0.26?(6). In the crystal, mol­ecules are linked by O—H?O hydrogen bonds into chains with graph-set notation C(5) along [100]. Weak C—H?O interactions also occur.

Forezi, Luana da Silva Magalhaes; Silva, Marcos Moitrel Pequeno; Santos, Fernanda da Costa; Ferreira, Vitor Francisco; de Souza, Maria Cecilia Bastos Vieira

2013-01-01

115

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

116

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

National Technical Information Service (NTIS)

A 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 se...

1982-01-01

117

Low cost brine tolerant sulfonate and sulfate surfactants having 1,3-dyhydrocharboxy-2-propyl hydrophobic tails  

SciTech Connect

Novel sulfonate and sulfate surfactants which have low interfacial tension at high salinity, and their use in enhanced oil recovery are disclosed. These surfactants may be made from relatively inexpensive intermediates, such as monohydric alcohols and epichlorohydrin. These surfactants have 1,3-dihydrocarboxy-2-propyl hydrophobic tails linked by ethoxy linkages to sulfate or alkyl sulfonate moieties.

Hoskin, D. H.

1985-05-07

118

Synthesis and Biological Evaluation of 2-Hydroxy-3-[(2-aryloxyethyl)amino]propyl 4-[(Alkoxycarbonyl)amino]benzoates  

PubMed Central

A series of twenty substituted 2-hydroxy-3-[(2-aryloxyethyl)amino]propyl 4-[(alkoxycarbonyl)amino]benzoates were prepared and characterized. As similar compounds have been described as potential antimycobacterials, primary in vitro screening of the synthesized carbamates was also performed against two mycobacterial species. 2-Hydroxy-3-[2-(2,6-dimethoxyphenoxy)ethylamino]-propyl 4-(butoxycarbonylamino)benzoate hydrochloride, 2-hydroxy-3-[2-(4-methoxyphenoxy)ethylamino]-propyl 4-(butoxycarbonylamino)benzoate hydrochloride, and 2-hydroxy-3-[2-(2-methoxyphenoxy)ethylamino]-propyl 4-(butoxycarbonylamino)benzoate hydrochloride showed higher activity against M. avium subsp. paratuberculosis and M. intracellulare than the standards ciprofloxacin, isoniazid, or pyrazinamide. Cytotoxicity assay of effective compounds was performed using the human monocytic leukaemia THP-1 cell line. Compounds with predicted amphiphilic properties were also tested for their effects on the rate of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. All butyl derivatives significantly stimulated the rate of PET, indicating that the compounds can induce conformational changes in thylakoid membranes resulting in an increase of their permeability and so causing uncoupling of phosphorylation from electron transport.

Tengler, Jan; Kapustikova, Iva; Pesko, Matus; Keltosova, Stanislava; Mokry, Petr; Kollar, Peter; O'Mahony, Jim; Kral'ova, Katarina; Jampilek, Josef

2013-01-01

119

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

SciTech Connect

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 LiPF{sub 6} and LiAsF{sub 6}. The use of acyclic, unsymmetric alkyl carbonate solvents, such as ethyl methyl carbonate (EMC) and MPC in Li-ion based electrolytes, increases the stability of the graphite electrode. Whereas a small amount of EC is still needed as cosolvent in EMC solutions to obtain stable surface films on graphite electrodes, the authors show here that the surface films produced on graphite in MPC solutions (without added EC) are highly stable, allowing reversible Li-ion intercalation. To understand this trend, they investigated the surface chemistry developed on lithium and carbon electrodes in MPC solutions in conjugation with electrochemical studies.

Ein-Eli, Y.; McDevitt, S.F. [Covalent Associates Inc., Woburn, MA (United States); Aurbach, D.; Markovsky, B.; Schechter, A. [Bar-Ilan Univ., Ramat Gan (Israel). Dept. of Chemistry

1997-07-01

120

Control of laser induced molecular fragmentation of n-propyl benzene using chirped femtosecond laser pulses  

PubMed Central

We present the effect of chirping a femtosecond laser pulse on the fragmentation of n-propyl benzene. An enhancement of an order of magnitude for the relative yields of C3H3+ and C5H5+ in the case of negatively chirped pulses and C6H5+ in the case of positively chirped pulses with respect to the transform-limited pulse indicates that in some fragmentation channel, coherence of the laser field plays an important role. For the relative yield of all other heavier fragment ions, resulting from the interaction of the intense laser field with the molecule, there is no such enhancement effect with the sign of chirp, within experimental errors. The importance of the laser phase is further reinforced through a direct comparison of the fragmentation results with the second harmonic of the chirped laser pulse with identical bandwidth.

Goswami, Tapas; Karthick Kumar, S.K.; Dutta, Aveek; Goswami, Debabrata

2009-01-01

121

Atropisomerization of di-para-substituted propyl-bridged biphenyl cyclophanes.  

PubMed

The influence of electron donors and electron acceptors of variable strength in the 4 and 4' position of 2 and 2' propyl-bridged axial chiral biphenyl cyclophanes on their atropisomerization process was studied. Estimated free energies ?G(‡)(T) of the rotation around the central biphenyl bond which were obtained from (1)H-NMR coalescence measurements were correlated to the Hammett parameters ?(p) as a measure for electron donor and acceptor strength. It is demonstrated that the resulting nice linear correlation is mainly based on the influence of the different substituents on the ?-system of the biphenyl cyclophanes. By lineshape analysis the rate constants were calculated and by the use of the Eyring equation the enthalpic and entropic contributions were evaluated. Density functional theory calculations show a planar transition state of the isomerization process and the calculated energy barriers based on this reaction mechanism are in good agreement with the experimentally obtained free energies. PMID:23059962

Rotzler, Jürgen; Gsellinger, Heiko; Bihlmeier, Angela; Gantenbein, Markus; Vonlanthen, David; Häussinger, Daniel; Klopper, Wim; Mayor, Marcel

2013-01-01

122

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

123

The Use of Chlorhexidine/n-Propyl Gallate (CPG) as an Ambient-Temperature Urine Preservative  

NASA Technical Reports Server (NTRS)

A safe, effective ambient temperature urine preservative, chlorhexidine/n-propyl gallate (CPG), has been formulated for use during spacefli ght that reduces the effects of oxidation and bacterial contamination on sample integrity while maintaining urine pH. The ability of this preservative to maintain stability of nine key analytes was evaluated for a period of one year. CPG effectively maintained stability of a mmonia, total nitrogen, 3-methylhistidine, chloride, sodium, potassiu m, and urea; however, creatinine and osmolality were not preserved by CPG. These data indicate that CPG offers prolonged room-temperature storage for multiple urine analytes, reducing the requirements for f rozen urine storage on future spaceflights. Iii medical applications on Earth, this technology can allow urine samples to be collected in remote settings and eliminate the need to ship frozen samples.

Nillen, Jeannie L.; Smith, Scott M.

2003-01-01

124

(Z)-N-(2,6-Diiso-propyl-phen-yl)-4-nitro-benzimidoyl chloride  

PubMed Central

In the title compound, C19H21ClN2O2, the aromatic rings are approximately perpendicular to each other, subtending a dihedral angle of 87.7?(1)°. In the crystal, the 4-nitro­phenyl groups of pairs of neighbouring mol­ecules are parallel and oriented head-to-tail with a ring centroid–centroid distance of 3.9247?(12)?Å, leading to a ?–? inter­action between the pair. The faces of each phenyl ring of the 2,6-diiso­propyl­phenyl group inter­act with two different groups, viz. a chloro group of an adjacent mol­ecule on one side and the edge of the 4-nitro­phenyl ring of a second mol­ecule on the other side.

El-Hiti, Gamal A.; Smith, Keith; Jones, Dyfyr Heulyn; Masmali, Ali; Kariuki, Benson M.

2013-01-01

125

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.

Duhaime, Donna E.; Bown, Alan W.

1983-01-01

126

Densities and vapor-liquid equilibria in binary mixtures formed by propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol at 160.0 kPa  

SciTech Connect

Densities and excess volumes were determined at 298.15 K for propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol. The results of those quantities were then correlated to get the concentrations of vapor-liquid equilibrium obtained isobarically at 160 kPa for the same mixtures. Two mixtures show azeotropes: for propyl methanoate (1) + ethanol (2), x{sub 1} = 0.443 at T = 358.7 K; and for propyl methanoate (1) + propan-1-ol (2), x{sub 1} = 0.762 at T = 368.2 K. The mixtures are thermodynamically consistent, and the predictions made using several group-contribution models are satisfactory.

Falcon, J.; Ortega, J.; Gonzalez, E. [Escuela Superior de Ingenieros Industriales, Las Palmas (Spain). Laboratorio de Termodinamica y Fisicoquimica] [Escuela Superior de Ingenieros Industriales, Las Palmas (Spain). Laboratorio de Termodinamica y Fisicoquimica

1996-07-01

127

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

PubMed

Adsorption of aromatic organic acids: benzoic acid (BA), salicylic acid (SA), p-aminobenzoic acid (pABA) and nicotinic acid (NA), onto high area activated carbon cloth from solutions in 0.4 M H(2)SO(4), in water at natural pH, in 0.1 M NaOH and also from solutions having pH 7.0 were studied by in situ UV-spectroscopic technique. The first-order rate law was found to be applicable for the kinetic data of adsorption. The rates and extents of adsorption of the organic acids were the highest from water or 0.4 M H(2)SO(4) solutions and the lowest from 0.1 M NaOH solution. The order of rates and extents of adsorption of the four organic acids in each of the four solutions (0.4 M H(2)SO(4), water, solution of pH 7.0 and 0.1 M NaOH) was determined as SA>BA>NA approximately pABA. These observed orders were explained in terms of electrostatic, dispersion and hydrogen bonding interactions between the surface and the adsorbate species, taking the charge of the carbon surface and the adsorbate in each solution into account. Adsorption of BA in molecular form or in benzoate form was analyzed by treating the solution as a mixture of two components and applying Lambert-Beer law to two-component system. The adsorption isotherm data of the systems studied were derived at 30 degrees C and fitted to Langmuir and Freundlich equations. PMID:16442224

Ayranci, Erol; Duman, Osman

2006-08-25

128

Antiviral Evaluation of Octadecyloxyethyl Esters of (S)-3-Hydroxy-2-(phosphonomethoxy)propyl Nucleosides Against Herpesviruses and Orthopoxviruses?  

PubMed Central

Our previous studies showed that esterification of (S)-3-hydroxy-2-(phosphono-methoxy)propyl]adenine (HPMPA) or 1-(S)-[3-hydroxy-2-(phosphonomethoxy)-propyl]cytosine (HPMPC) with alkoxyalkyl groups such as hexadecyloxypropyl (HDP) or octadecyloxyethyl (ODE) resulted in large increases in antiviral activity and oral bioavailability. The HDP- and ODE- esters of HPMPA were shown to be active in cells infected with human immunodeficiency virus, type 1 (HIV-1), while HPMPA itself was virtually inactive. To explore this approach in greater detail, we synthesized four new compounds in this series, the ODE esters of 9-(S)-[3-hydroxy-2-(phosphonomethoxy)-propyl]guanine (HPMPG), 1-(S)-[3-hydroxy-2-(phosphono-methoxy)propyl]thymine (HPMPT), 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-2,6-diaminopurine (HPMPDAP) and 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-2-amino-6-cyclopropylaminopurine. (HPMP-cPrDAP) and evaluated their antiviral activity against herpes simplex virus, type 1 (HSV-1), human cytomegalovirus (HCMV), and vaccinia, cowpox and ectromelia. Against HSV-1, subnanomolar EC50 values were observed with ODE-HPMPA and ODE-HPMPC while ODE-HPMPG had intermediate antiviral activity with an EC50 of 40 nanomolar. In HFF cells infected with HCMV, the lowest EC50 values were observed with ODE-HPMPC, 0.9 nanomolar. ODE -HPMPA was highly active with an EC50 of 3 nanomolar, while ODE-HPMPG and ODE-HPMPDAP were also highly active with EC50s of 22 and 77 nanomolar, respectively. Against vaccinia and cowpox viruses, ODE-HPMPG and ODE-HPMPDAP were the most active and selective compounds with EC50 values of 20 to 60 nanomolar and selectivity index values of 600 to 3,500. ODE-HPMPG was also active against ectromelia virus with an EC50 value of 410 nanomolar and a selectivity index value of 166. ODE-HPMPG and ODE-HPMPDAP are proposed for further preclinical evaluation as possible candidates for treatment of HSV, HCMV or orthopoxvirus diseases.

Valiaeva, Nadejda; Prichard, Mark N.; Buller, R. Mark; Beadle, James R.; Hartline, Caroll B.; Keith, Kathy A.; Schriewer, Jill; Trahan, Julissa; Hostetler, Karl Y.

2009-01-01

129

Functionalization of single-walled carbon nanotubes with N-[3-(trimethoxysilyl)propyl]ethylenediamine and its cobalt complex  

PubMed Central

The reaction of N-[3-(trimethoxysilyl)propyl]ethylenediamine with fluorinated carbon nanotubes (F-CNT) produced the corresponding aminoalkylalkoxysilane functionalized carbon nanotubes. Cobalt salt is then complexed to this functionalized carbon nanotubes by the addition of cobalt chloride to form cobalt complexed nanocomposite in high yield. This composite and precursors were characterized by using Fourier transform infra-red spectroscopy (FTIR), transmission electron microscopy (TEM), energy dispersive spectral (EDS) and thermal gravimetric analysis (TGA). The nanoparticulate metal complexes of functionalized carbon nanotubes generate new nanostructure with several practical applications. The reaction of N-[3-(trimethoxysilyl)propyl]ethylenediamine with cobalt (II) chloride salt afford the cobalt complex nanoparticles, with particle sizes less than 10 nm.

Oki, Aderemi; Adams, Luqman; Luo, Zhipping; Osayamen, Edigin; Biney, Paul; Khabashesku, Valery

2008-01-01

130

Catalytic synthesis of isobutyraldehyde from methanol and n-propyl alcohol over titanium oxide-supported vanadium oxide catalysts  

SciTech Connect

Catalytic synthesis of isobutyraldehyde from methanol and n-propyl alcohol was achieved by using titanium oxide-supported vanadium oxide catalysts in one step. At high conversion (> 90%), isobutyraldehyde was formed in high yield (> 60%) with minor amounts of propionaldehyde, propane, and isobutane. The experimental results indicated that isobutane was formed by a propane intermediate and isobutyraldehyde was formed by a propionaldehyde intermediate in the reaction.

Feylong Wang; Wenshin Lee; Yifang Liou; Licheng Chen (Providence Univ., Taichung Hsien (Taiwan, Province of China))

1993-01-01

131

Simultaneous analysis of BHA, TBHQ, BHT and propyl gallate by gas chromatography as extracted from refined vegetable oil  

Microsoft Academic Search

A method has been developed for the simultaneous gas chromatographic (GC) analysis of 4 phenolic antioxidants extracted from\\u000a refined cottonseed oil. The antioxidants in the study were butylated hydroxyanisole (BHA), tertiary butyl hydroquinone (TBHQ),\\u000a butylated hydroxytoluene (BHT), and propyl gallate (PG). The method involves extraction with acetonitrile, followed by silyl\\u000a derivatization prior to GC injection. The method was applied to

D. M. Wyatt

1981-01-01

132

Synthesis of covalently bonded cellulose derivative chiral stationary phases with a bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate  

Microsoft Academic Search

A bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate (TEPI) was initially adopted as a spacer reagent to prepare the bonded types of chiral stationary phases (CSPs) with cellulose derivatives. The silica-based CSPs were chemically prepared with non-regioselective and regioselective approaches and their chiral resolving capabilities were evaluated in terms of HPLC resolution of test enantiomers. It was observed that the chiral recognition

Xiaoming Chen; Yueqi Liu; Feng Qin; Liang Kong; Hanfa Zou

2003-01-01

133

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

134

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 50-4000cm(-1) and 450-4000cm(-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

135

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

136

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

137

Visible-light-promoted degradation of the antioxidants propyl gallate and t-butylhydroquinone: mechanistic aspects.  

PubMed

The kinetic and mechanistic aspects of the visible-light-mediated photodegradation of the phenolic antioxidants (PA), propyl gallate (PG), and t-butylhydroquinone (TBHQ), employing riboflavin (Rf) as photosensitizer, have been studied by time-resolved and stationary techniques. The photosensitizer Rose Bengal (RB) was used for auxiliary experiments. Results show the occurrence of chemical transformations on PA with the participation of electronically excited states of Rf and different reactive oxygen species (ROS) generated from these states. With 0.02 mM Rf and 1.0 mM PA, the electronically excited triplet state of Rf is quenched by PA, in a competitive manner with the dissolved oxygen. As a consequence, a cascade of photoprocesses produces singlet oxygen (O(2)((1)?(g))) and H(2)O(2) in the case of PG and, O(2)((1)?(g)), H(2)O(2) and HO(•) in the case of TBHQ. The participation of these species is supported by experiments of oxygen consumption carried out in the presence of specific ROS scavengers. TBHQ has a relatively high capacity for O(2)((1)?(g)) physical deactivation and a low photodegradation efficiency by the oxidative species. Comparatively, it can be asserted that TBHQ has a higher antioxidant capacity than PG. PMID:22732940

Criado, Susana; Allevi, Carolina; García, Norman A

2012-01-01

138

Role of redox signaling regulation in propyl gallate-induced apoptosis of human leukemia cells.  

PubMed

Propyl gallate (PG) is a synthetic antioxidant that has been used in processed food and medicinal preparations. The anti-cancer effect of PG in leukemia is unclear. In the present study, we demonstrate that PG reduced cell viability in THP-1, Jurkat, and HL-60 leukemia cells and induced apoptosis in THP-1 cells. PG activated caspases 3, 8, and 9 and increased the levels of p53, Bax, Fas, and Fas ligand. PG activated mitogen-activated protein kinases (MAPKs), inhibited nuclear translocation of the nuclear factor erythroid 2-related factor 2 (Nrf-2) and induced intracellular glutathione (GSH) depletion. In addition, PG increased superoxide dismutase-1 expression and decreased intracellular levels of reactive oxygen species. Our data show for the first time that an early event of PG-induced apoptosis is MAPKs/Nrf-2-mediated GSH depletion and that PG induced apoptosis via multiple pathways in human leukemia. PG might serve as a potential chemotherapeutic agent or food supplement for human leukemia patients. PMID:21112369

Chen, Ching-Hsein; Lin, Wan-Chen; Kuo, Chien-Neng; Lu, Fung-Jou

2011-02-01

139

Chemical ionization of phenyl n -propyl ether and methyl substituted analogs: Propene loss initiated by competing proton transfer to the oxygen atom and the aromatic ring  

Microsoft Academic Search

The mechanism of propene loss from protonated phenyl n-propyl ether and a series of mono-, di-, and trimethylphenyl n-propyl ethers has been examined by chemical ionization (CI) mass spectrometry in combination with tandem mass spectrometry\\u000a experiments. The role of initial proton transfer to the oxygen atom and the aromatic ring, respectively, has been probed with\\u000a the use of deuterated CI

Bogdan Bogdanov; Henri E. K. Matimba; Steen Ingemann; Nico M. M. Nibbering

1996-01-01

140

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

141

The excellent water-solubility of N-[3-(dimethyl-amino)propyl] docosanamide chloride : the most eco-friendly cationic hair conditioning agent.  

PubMed

A new hair-conditioning agent, N-[3-(dimethylamino)propyl]docosanamide (APA-22) hydrochloric acid salt (APA-22 HCl), has excellent solubility in water with a solubility limit over 10-times larger than that of other APA hydrochloric salts with shorter alkyl chain lengths. The physicochemical characteristics of APA-22 HCl were studied at 25 degrees C by using equilibrium surface tension (gamma), solubilization of an oil-soluble dye, steady-state fluorescence, and chloride ion selective electrode techniques. The APA-22 HCl salt is considered to form an aggregate at a concentration, C(1), which is about twice the concentration of the solubility limit of APAs with shorter alkyl chains. At a higher concentration, C(2), the aggregates of APA-22 HCl start forming another kind of aggregate, which is able to solubilize oil-soluble materials. That is, C(1) is considered to represent the critical aggregation concentration (cac) and C(2) a morphology transition. In the concentration region between C(1) and C(2) the solutions are seemingly transparent whereas at above C(2) they appear bluish or translucent. Since the Krafft point of APA-22 HCl is 55 degrees C, all the solutions, including the aggregates, are thought to exist in metastable states. Notably, however, these metastable solutions do not change significantly over a few months. The excellent solubility of APA-22 HCl in water is considered to be a result of this unique stepwise aggregation with increasing concentration. PMID:18781052

Sakai, Takaya; Inoue, Katsuhisa; Yamane, Masayuki; Toyo, Takamasa; Nishiyama, Naohiro; Kaneko, Youhei

2008-01-01

142

Site-specific mutagenesis induced by single O6-alkylguanines (O6-n-propyl, O6-n-butyl, O6-n-octyl) in vivo.  

PubMed

The mutagenic activity of a series of longer chain O6-n-alkylguanine residues (O6-n-propyl, O6-n-butyl, O6-n-octyl) has been analyzed using a plasmid molecule (pUC 9) in which single O6-alkylguanines were positioned in the unique Pstl recognition site by shot gun ligation (Nucleic Acids Res. 13, 3305-3316 (1985)) of overlapping synthetic oligonucleotides. After transfection of these vectors into E. coli cells having normal DNA repair systems, progeny plasmids were produced, of which 2.6%, 2.8% and 4.3% were mutated in their Pstl site when containing O6-n-propylguanine, O6-n-butylguanine, O6-n-octylguanine, respectively. DNA sequence analysis of mutant plasmid genomes revealed that O6-n-propylguanine and O6-n-butylguanine induced exclusively G-->A transitions located specifically at the preselected site. O6-n-octylguanine induced apart from G-->A transitions (70%) also targeted G-->T transversions (30%). These results indicate that the mutation frequency of longer chain O6-alkylguanines can be substantial in cells with normal repair systems and that the mutation pattern depends on the nature of the alkyl group. PMID:8367292

Baumgart, P M; Kliem, H C; Gottfried-Anacker, J; Wiessler, M; Schmeiser, H H

1993-08-11

143

Site-specific mutagenesis induced by single O6-alkylguanines (O6-n-propyl, O6-n-butyl, O6-n-octyl) in vivo.  

PubMed Central

The mutagenic activity of a series of longer chain O6-n-alkylguanine residues (O6-n-propyl, O6-n-butyl, O6-n-octyl) has been analyzed using a plasmid molecule (pUC 9) in which single O6-alkylguanines were positioned in the unique Pstl recognition site by shot gun ligation (Nucleic Acids Res. 13, 3305-3316 (1985)) of overlapping synthetic oligonucleotides. After transfection of these vectors into E. coli cells having normal DNA repair systems, progeny plasmids were produced, of which 2.6%, 2.8% and 4.3% were mutated in their Pstl site when containing O6-n-propylguanine, O6-n-butylguanine, O6-n-octylguanine, respectively. DNA sequence analysis of mutant plasmid genomes revealed that O6-n-propylguanine and O6-n-butylguanine induced exclusively G-->A transitions located specifically at the preselected site. O6-n-octylguanine induced apart from G-->A transitions (70%) also targeted G-->T transversions (30%). These results indicate that the mutation frequency of longer chain O6-alkylguanines can be substantial in cells with normal repair systems and that the mutation pattern depends on the nature of the alkyl group. Images

Baumgart, P M; Kliem, H C; Gottfried-Anacker, J; Wiessler, M; Schmeiser, H H

1993-01-01

144

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

145

Physiological disposition of aerosolized 4-((3-(4-acetyl-3-hydroxy-2-propylphenoxy)propyl)sulfonyl)-gamma -oxobenzenebutanoate (L-648,051) in rats  

SciTech Connect

/sup 14/C-labeled 4-((3-(4-acetyl-3-hydroxy-2-propylphenoxy)propyl)-sulfonyl)-gamma- oxobenzenebutanoate (L-648,051) was suspended in Freon under pressure and injected into rat lungs via a tracheal cannula. The particle size of the drug was 1 to 5 microns and the mean dose was approximately 0.2 mg/kg. Levels of radioactivity in the lung/trachea declined in a monoexponential manner. Absorption, estimated from radioactivity remaining in the lung and trachea, was 73% in 1 hr and 95% in 4 hr. L-648,051 and its pharmacologically active metabolite L-657,098 (formed by ketoreduction of the butanoic acid moiety of L-648,051) accounted for 96% of the radioactivity in the lung at 10 min after the dose and 91% after 60 min. The lung:plasma concentration ratio of active drug (L-648,051 plus L-657,098) was at least 176:1 at 10 min and 17:1 at 60 min (compared with 1:1 after 2 mg/kg iv) suggesting that aerosol administration of L-648,051 in humans may result in an ideal therapeutic ratio, with high levels of pharmacologically active ingredient in the lung and low levels in the plasma.

Tocco, D.J.; Duncan, A.E.; deLuna, F.A.; Wells, G.

1988-09-01

146

New pleconaril and [(biphenyloxy)propyl]isoxazole derivatives with substitutions in the central ring exhibit antiviral activity against pleconaril-resistant coxsackievirus B3.  

PubMed

Amino acid 1092 (AA1092) in capsid protein 1 of coxsackievirus B3 (CVB3) is located in close vicinity to the central phenoxy group of capsid binders (i.e. pleconaril). Whereas isoleucine is associated with drug susceptibility, leucine and methionine confer resistance to pleconaril. In the present study, novel analogues with different substitutions in the central phenoxy group were synthesized to study their influence on anti-CVB3 activity with the aim to overcome pleconaril resistance. Two [(biphenyloxy)propyl]isoxazoles and pleconaril were synthesized without methyl groups in the central phenoxy ring using Suzuki coupling reaction and tested for antiviral activity against the pleconaril-resistant CVB3 Nancy. Furthermore, pleconaril with 3-methyl, 3-methoxy, 3-bromine, 2,3-dimethyl in the central ring as well as the external rings in meta position were synthesized for structure-activity relationship analysis with CVB3 variants containing leucine, methionine or isoleucine at position 1092, other coxsackieviruses B (CVB) as well as several rhinoviruses. The results demonstrate a high impact of substituents in the central ring of capsid inhibitors for anti-enteroviral activity. Pleconaril resistance of CVB3 based on Leu1092 or Met1092 was overcome by unsubstituted analogues or by monosubstitution with 3-methyl as well as 3-bromine in the central phenyl. The 3-bromine derivative inhibited a broad spectrum of CVB and rhinoviruses. PMID:18840470

Schmidtke, Michaela; Wutzler, Peter; Zieger, Romy; Riabova, Olga B; Makarov, Vadim A

2009-01-01

147

In situ derivatization hollow fiber mediated liquid phase microextraction of alkylphosphonic acids from water  

Microsoft Academic Search

Alkylphosphonic acids (APAs), particularly the methyl-, ethyl-, isopropyl- and n-propyl-phosphonic acids are important markers of extremely toxic nerve agents. Hence, their detection and identification is of vital importance to verification of chemical weapons convention (CWC). Verification analysis of CWC requires development of fast, reliable, simple and reproducible sample preparation methods of water and soil samples. Present investigation is focused on

Deepak Pardasani; Pankaj K. Kanaujia; A. K. Gupta; Vijay Tak; R. K. Shrivastava; D. K. Dubey

2007-01-01

148

Derivatives of Gallic Acid Induce Apoptosis in Tumoral Cell Lines and Inhibit Lymphocyte Proliferation  

Microsoft Academic Search

The effect of gallic acid (3,4,5-trihydroxybenzoic acid) and its alkyl esters (methyl, propyl, octyl, and lauryl) has been studied on several tumoral and nontumoral cells. Three types of behavior have been observed; the first type is represented by the mouse B cell lymphoma Wehi 231 cell line in which death occurs according to the biochemical characteristics of classical apoptosis showing

Antonio Serrano; Carmen Palacios; Garbiñe Roy; Constantino Cespón; Mar??a L. Villar; Mercedes Nocito; Pedro González-Porqué

1998-01-01

149

Improvement of aripiprazole solubility by complexation with (2-hydroxy)propyl-?-cyclodextrin using spray drying technique.  

PubMed

Due to the fact that the number of new poorly soluble active pharmaceutical ingredients is increasing, it is important to investigate the possibilities of improvement of their solubility in order to obtain a final pharmaceutical formulation with enhanced bioavailability. One of the strategies to increase drug solubility is the inclusion of the APIs in cyclodextrins. The aim of this study was to investigate the possibility of aripiprazole solubility improvement by inclusion in (2-hydroxy)propyl-?-cyclodextrin (HPBCD) and simultaneous manipulation of pH of the medium and addition of polyvinylpyrrolidone. Aripiprazole-HPBCD complexes were prepared by spray drying aqueous drug-HPBCD solutions, and their properties were compared with those prepared by solvent-drop co-grinding and physical mixing. The obtained powders were characterized by thermoanalytical methods (TGA and DSC), FTIR spectroscopy, their dissolution properties were assessed, while the binding of aripiprazole into the cavity of HPBCD was studied by molecular docking simulations. The solubilization capacity was found to be dependent on pH as well as the buffer solution's ionic composition. The presence of PVP in the formulation could affect the solubilization capacity significantly, but further experimentation is required before its effect is fully understood. On the basis of solubility studies, the drug/HPBCD stoichiometry was found to be 1:3. The spray-dried products were free of crystalline aripiprazole, they possessed higher solubility and dissolution rate, and were stable enough over a prolonged period of storage. Spray drying of cyclodextrin solutions proved to be an appropriate and efficient technique for the preparation of highly soluble inclusion compounds of aripiprazole and HPBCD. PMID:22535520

Mihajlovic, Tijana; Kachrimanis, Kyriakos; Graovac, Adrijana; Djuric, Zorica; Ibric, Svetlana

2012-06-01

150

Dissociation of propyl radicals and other reactions on a C3H7 potential.  

PubMed

In this article we make theoretical predictions of the thermal rate coefficients for a series of elementary reactions on a C3H7 potential. Perhaps most importantly, we study the association/dissociation reactions for n-C3H7 and i-C3H7 [CH3 + C2H4(+M) ? n-C3H7(+M), C3H6 + H(+M) ? n-C3H7(+M), and C3H6 + H(+M) ? i-C3H7(+M)], where n-C3H7 and i-C3H7 are the propyl radicals and C3H6 is propene. However, in order to provide more information for our kinetic model, we have also included analyses of the association/elimination reaction [C3H6 + H ? CH3 + C2H4] and the abstraction reactions [C3H6 + H ? CH2CHCH2 + H2, C3H6 + H ? CH3CCH2 + H2, C3H6 + H ? CH3CHCH + H2, and CH3 + C2H4 ? CH4 + C2H3]. The theory employs high-level electronic-structure methods to characterize the potential energy surface, conventional transition-state theory to calculate k(T) for the abstraction reactions, RRKM theory to calculate microcanonical, J-resolved rate coefficients for the dissociation processes, and master-equation methods to determine phenomenological rate coefficients k(T,p), for all of the nonabstraction reactions. The agreement between our theory and the experimental results available is remarkably good. The final results are cast in a form that is convenient for chemical kinetics modeling. PMID:23517024

Miller, James A; Klippenstein, Stephen J

2013-04-01

151

Tris(1,3-dichloro-2-propyl) phosphate perturbs the expression of genes involved in immune response and lipid and steroid metabolism in chicken embryos.  

PubMed

We previously demonstrated that in ovo exposure to the flame retardant tris(1,3-dichloro-2-propyl) phosphate (TDCPP) decreased plasma thyroxine levels, reduced growth parameters, and decreased gallbladder size in chicken embryos. In the current study DNA microarrays were used to evaluate global mRNA expression in liver tissue of male chicken embryos that exhibited the above mentioned effects. Injected doses were dimethyl sulfoxide vehicle control, 7.6 or 45 ?g TDCPP/g egg. TDCPP caused significant changes in the expression of five genes at the low dose and 47 genes at the high dose (False Discovery Rate p ? 0.1, fold change ? 1.5). The gene expression analysis suggested a compromised immune function, a state of cholestatic liver/biliary fibrosis, and disrupted lipid and steroid metabolism. Circulating bile acid levels were elevated, which is an indication of liver dysfunction, and plasma cholesterol levels were reduced; however, hepatic bile acid and cholesterol levels were unaltered. Interactome analyses identified apolipoprotein E, hepatocyte nuclear factor 4 alpha, and peroxisome proliferator-activated receptor alpha as key regulatory molecules involved in the effects of TDCPP. Our results demonstrate a targeted effect of TDCPP toxicity on lipid metabolism, including cholesterol, that helps explain the aforementioned phenotypic effects, as chicken embryos are highly dependent on yolk lipids for growth and maintenance throughout development. Finally, our results are in concordance with the literature that describes TDCPP as a cancer-causing agent, since the majority of dysregulated genes were involved in cancer pathways. PMID:24407104

Farhat, Amani; Buick, Julie K; Williams, Andrew; Yauk, Carole L; O'Brien, Jason M; Crump, Doug; Williams, Kim L; Chiu, Suzanne; Kennedy, Sean W

2014-03-01

152

Antiinflammatory Property of 3Aryl5-( n-propyl)-1,2,4-oxadiazoles and Antimicrobial Property of 3Aryl5-( n-propyl)-4,5-dihydro-1,2,4-oxadiazoles: Their Syntheses and Spectroscopic Studies  

Microsoft Academic Search

The synthesis of six 3-aryl-5-(n-propyl)-4,5dihydro-1,2,4-oxadiazoles 3a–f has been achieved in a facile manner by the reaction of an appropriate arylamidoxime 1a–f with butyraldehyde 2. Oxidation of 3a–f individually using MnO2 in CH2Cl2 or sodium hypochlorite in THF\\/H2O furnished 1,2,4-oxadiazoles 4a–f in good to excellent yields. Compounds 4a–f were also evaluated against inflammation. Except 4e, all of them reduced inflammation, however,

Rajendra M Srivastava; Analice de Almeida Lima; Osnir S Viana; Marcelo J da Costa Silva; Maria T. J. A Catanho; José Otamar F de Morais

2003-01-01

153

ARTICLES: Vapor-Liquid Equilibrium Data of Carbon Dioxide+Methyl Propionate and Carbon Dioxide+Propyl Propionate Systems  

NASA Astrophysics Data System (ADS)

High-pressure vapor-liquid equilibrium data for the binary systems of methyl propionate+carbon dioxide and propyl propionate+carbon dioxide were measured at pressure from 1.00 MPa to 12.00 MPa and temperature in the range from 313 K to 373 K. Experimental results were correlated with the Peng-Robinson equation of state with the two-parameter van der Waals mixing rule. At the same time, the Henry's coefficient, partial molar enthalpy change and partial molar entropy change of CO2 during dissolution at different temperature were also calculated.

Xu, Wei; Xie, Chuan-xin; Li, Hong-ling; Tian, Yi-ling

2010-06-01

154

1,3-Bis(3-ammonium-propyl)tetramethyldisiloxane-sulfate: Structural characterization and evaluation of some properties  

NASA Astrophysics Data System (ADS)

1,3-Bis(3-ammonium-propyl)tetramethyldisiloxane sulfate resulted from the reaction between 1,3-bis(3-aminopropyl)tetramethyldisiloxane with a proper transition metal (iron(III) or vanadium(IV) oxide) salt as anion generator and a carbonylic compound (4-imidazole carboxaldehyde or 2-hydroxybenzaldehyde) as a metal collector, in methanol, was thoroughly characterized. The compound's structure was proved by single-crystal X-ray diffraction and spectral (FT-IR, 1H NMR) analysis, while the thermal behavior was evaluated by thermogravimetry. Water vapor sorption capacity on the crystalline compound was measured in dynamic regime. The co-existence of hydrophobic bis(propyl)tetramethyldisiloxane moiety and telechelic hydrophilic groups constitutes a premise for surface activity, as confirmed by tensiometry. Formation of micelles and aggregates in solution was emphasized by dynamic light scattering and confirmed by AFM images taken on the spin coated films, both revealing closed values for size of the micelles (100-200 nm).

Nistor, Alexandra; Soroceanu, Alina; Shova, Sergiu; Cazacu, Maria

2012-08-01

155

Conformations and Barriers to Methyl Group Internal Rotation in Two Asymmetric Ethers: Propyl Methyl Ether and Butyl Methyl Ether  

NASA Astrophysics Data System (ADS)

The conformational preferences of the O-C-C-C unit are important in many biological systems with the unit generally preferring a gauche configuration compared to an anti configuration. Butyl methyl ether and propyl methyl ether provide very simple systems for this phenomenom to manifest. Pure rotational spectra of the title molecules have been recorded using chirped pulse Fourier transform microwave spectroscopy (CP-FTMW). In the case of butyl methyl ether, only one conformer has been observed. This conformer has torsional angles of COCC = 180°, OCCC = 62° and CCCC = 180° (anti-gauche-anti) and rotational constants of A = 10259.4591(33) MHz, B = 1445.6470(13) MHz, and C = 1356.2944(14) MHz. The rotational spectrum was doubled and has been analyzed to produce an effective barrier to methyl group internal rotation of 780(35) cm-1. A prior rotational spectroscopic study on propyl methyl ether had focused only on the high energy anti-anti conformer. We have analyzed spectra from the lowest energy anti-gauche conformer and the spectroscopic constants will be presented. A summary of the differences in conformational energies and methyl group internal rotation barriers for the class of aliphatic asymmetric ethers will be presented. K. N. Houk, J. E. Eksterowicz, Y.-D. Wu, C. D. Fuglesang, D. B. Mitchell. J. Am. Chem. Soc. 115 (4170), 1993. Hiroshi Kato, Jun Nakagawa, Michiro Hayashi. J. Mol. Spectrosc. 80 (272), 1980.

Long, B. E.; Dechirico, F.; Cooke, S. A.

2012-06-01

156

A uremic toxin, 3-carboxy-4-methyl-5-propyl-2-furanpropionate induces cell damage to proximal tubular cells via the generation of a radical intermediate.  

PubMed

3-Carboxy-4-methyl-5-propyl-2-furanpropionate (CMPF), a furan fatty acid uremic toxin (UT) and a substrate for organic ion transporters, contributes to the accumulation of CMPF in renal tubular cells. Although oxidative stress induced by UTs has been proposed as a mechanism of its toxicity in chronic kidney disease, little information is available regarding the redox property of CMPF and its relation to renal cell damage. The findings herein show that CMPF enhances the production of reactive oxygen species (ROS) in HK-2 cells in the presence of angiotensin II (A-II), an inducer of O(2)(·-). When iron is also present, CMPF and A-II induce the Fenton reaction, resulting in a further increase in ROS production. Such CMPF-induced oxidative stress increases TGF-?1 secretion in HK-2 cells, and a positive correlation between CMPF-induced ROS production and the secretion of active TGF-?1 was observed. CMPF caused a reduction in cell viability which was negatively correlated with intracellular ROS production. These negative effects of CMPF in HK-2 cells were completely suppressed by probenecid, an inhibitor of organic anion transport. Interestingly, in vitro ROS assays indicate that CMPF directly interacts with superoxide anion radicals (O(2)(·-)) and peroxy radicals (LOO) to produce CMPF radicals. The subsequent interaction of CMPF radicals with dissolved oxygen leads to the overproduction of O(2)(·-). Based on these findings, we conclude that CMPF, which accumulates in the renal cells, appears to play a prominent role as a pro-oxidant which subsequently leads to renal cellular damage via the overproduction of O(2)(·-). PMID:22898098

Miyamoto, Yohei; Iwao, Yasunori; Mera, Katsumi; Watanabe, Hiroshi; Kadowaki, Daisuke; Ishima, Yu; Chuang, Victor Tuan Giam; Sato, Keizo; Otagiri, Masaki; Maruyama, Toru

2012-11-01

157

N-((4-arylpiperazin-1-yl)-propyl)-2-aza-spiro(4.4) nonane and (4.5)decane-1,3-dione derivatives  

Microsoft Academic Search

A series of twenty new N-((4-arylpiperazin-1-yl)-propyl)-2-aza-spiro(4.4)nonane- and (4.5)decane-1,3-dione derivatives were synthesized and their anticonvulsant activity was evaluated in maximal electroshock (MES) andsc pentertazole (scPTZ) tests. Their neurotoxicity was examined as well. Although no antiseizure properties of the investigated compounds were found in the MES model, eight of them were active in the scPTZ test and three, namely 2-{3-(4-(2-fluorophenyl)-piperazin-1yl)-propyl}-2- aza-spiro(4.4)nonane-1,3-dione (7),

Jolanta Obniska; Sijka Charakchieva-Minol; Krystyna Nêdza; Andrzej J. Bojarski

158

QSAR, docking studies and pharmacophore identification of phenylmethyl phenoxy propyl amino propanoic acid derivatives as leukotriene A4 hydrolase inhibitors.  

PubMed

The enzyme leukotriene A4 (LTA4) plays an important role as precursor of slow reactive substances as LTC4, LTD4, and LTE4. It is an attractive target for molecular modeling and QSAR study. Our effort is mainly focused on exploring the SAR for inhibitors of the LTA4 hydrolase through docking study, pharmacophore modeling and molecular descriptor study. The binding of these small molecules on LTA4 hydrolase enzyme was described by the models developed on 2D molecular descriptors, with good predictive power (39 compounds, 6 descriptors, r2 0.98, SEE 0.167, F-value 268.53, q2 0.90, r2 adj 0.97, P-value < 0.0001, SD of residuals 0.15). Docking studies were employed to presume the probable binding conformation of these analogues and exploring the SAR for the compounds. The novel pharmacophore represents the ligand features that are involved in interactions with the target protein, as well as the space around the ligand occupied by the protein. The efforts are aimed to discover the SAR for the inhibitors of LTA4 hydrolase through techniques of QSAR, docking and pharmacophore. PMID:20931764

Sonawane, Lalit V; Bari, Sanjaykumar B

2010-05-01

159

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...

160

Reduced Renal Clearance of Furancarboxylic Acid, a Major Albumin-Bound Organic Acid, in Undialyzed Uremic Patients  

Microsoft Academic Search

3-Carboxy-4-methyl-5-propyl-2-furanpropionic acid (CMPF) is accumulated in uremic serum as a major albumin-bound organic acid. We determined both serum and urine levels of total CMPF to calculate renal clearance of CMPF in healthy subjects and undialyzed uremic patients. Urinary excretion of CMPF and renal clearance were significantly decreased in the uremic patients. The relative clearance ratios of CMPF to creatinine were

Mitsuhiko Sato; Masako Koyama; Takashi Miyazaki; Toshimitsu Niwa

1996-01-01

161

Studies of naturally occurring modifications of sialic acids by fast-atom bombardment-mass spectrometry. Analysis of positional isomers by periodate cleavage.  

PubMed

A variety of modifications of sialic acids have been described in nature. There are currently many difficulties in the detection and quantitation of these modified sialic acids from biological sources. We report here that fast-atom bombardment-mass-spectrometry (FAB-MS) of native sialic acids provides specific detection and quantitation of many previously known compounds. Derivatization of the sialic acids by reduction and peracylation under acidic conditions prior to FAB-MS provides further confirmation of their identity and improves the sensitivity of detection. Samples containing as little as 100 ng of a derivatized sialic acid loaded onto the FAB target allowed accurate identification. Mixtures of sialic acids could be analyzed, and minor components were seen, at levels undetectable by other currently known techniques. Analysis of known mixtures of different sialic acids gave reproducible relative signal intensities, indicating that quantitative data can be derived from the FAB-MS spectra. After reduction and peracylation, each sialic acid gave two major molecular ions, corresponding to the fully derivatized linear species and a lactone form, and a minor ion, corresponding to an anhydro form. Lactone formation was minimal in the case of four substituted sialic acids, indicating that the hydroxyl group at the 4-position is involved in lactonization. Differentiation between different positional isomers of the modified sialic acids could be achieved using controlled degradation with periodate, tagging of the fragments with p-aminobenzoic acid ethyl ester under acid reducing conditions, peracylation, and FAB-MS of the derivatized products. We used this FAB-MS strategy to identify a novel sialic acid, 8-O-methyl-7,9-di-O-acetyl-N-glycolyl-neuraminic acid from the starfish Pisaster brevispinus, and to demonstrate the presence of a previously undetected sialic acid, 4,8-anhydro-N-acetyl-neuraminic acid in acid hydrolysates of horse serum. We also use FAB-MS to show that the alkaline conditions traditionally used for analytical de-O-acetylation of sialic acids causes substantial conversion of 4-O-acetylated sialic acids into the same anhydro compound. PMID:2159468

Manzi, A E; Dell, A; Azadi, P; Varki, A

1990-05-15

162

5-Fluoro-3-phenyl-N?-(4-propyl-cyclo-hexyl-idene)-1H-indole-2-carbohydrazide  

PubMed Central

In the title compound, C24H26FN3O, the cyclo­hexane ring adopts a chair conformation; the propyl substituent is in an equatorial orientation and the bond-angle sum at the C atom bonded to the carbohydrazide N atom is 360.0°. The dihedral angle between the 1H-indole ring system and the phenyl ring is 82.77?(13)°. A weak intra­molecular C—H?? contact occurs. In the crystal, pairs of mol­ecules related by a crystallographic twofold axis are linked by bifurcated N—H?(O,N) hydrogen bonds; a C—H?O inter­action occurs between the same pair. The dimers are linked by C—H?F and C—H?? inter­actions, generating a three-dimensional network.

Celikesir, Sevim Turktekin; Akkurt, Mehmet; Ustundag, Gokce Cihan; Buyukgungor, Orhan

2013-01-01

163

Propyl gallate inhibits TPA-induced inflammation via the nuclear factor-?B pathway in human THP-1 monocytes  

PubMed Central

Propyl gallate (PG) is an antioxidant that has been used as an additive in several foods to protect against oxidation. The present study examined the anti-inflammatory effect of PG on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in human THP-1 monocytes. Pretreatment with PG markedly inhibited the TPA-induced expression levels of cyclooxygenase-2 and prostaglandin E2. The application of PG significantly inhibited the nuclear translocation of p65, a subunit of nuclear factor-?B (NF-?B) and phosphorylation of p65 (Ser536) in TPA-treated THP-1 cells. PG also inhibited the phosphorylation of I?B and I?B kinase. These results indicate that PG inhibits the inflammatory response by blocking the NF-?B signaling pathway in TPA-induced THP-1 monocytes. Therefore, PG may be useful as a therapeutic agent in inflammatory diseases.

HSU, HUNG-CHIH; LIN, WAN-CHEN; CHANG, PEY-JIUM; HONG, CHANG-ZERN; CHEN, CHING-HSEIN

2013-01-01

164

Synthesis and in vitro antiproliferative evaluation of novel N-alkylated 6-isobutyl- and propyl pyrimidine derivatives.  

PubMed

A series of novel N-alkylated C-6-isobutyl- or -propyl pyrimidine derivatives were synthesized and their antiproliferative effect was evaluated on a panel of tumor cell lines including leukemia cell line K562 and normal diploid human fibroblasts. N-methoxymethylated 5-methylpyrimidin-2,4-dione with di(benzyloxy)isobutyl at C-6 (14b) showed the strongest effect on the cell growth at micromolar concentrations. Mechanisms of action for the lipophilic compound 14b predicted in silico, pointed to its anticancer and antimetastatic potential exerted through inhibition of DNA or RNA polymerases and adhesion molecules. The latter mechanism has been supported in vitro for adherent tumor cell lines. PMID:24835982

Gazivoda Kraljevi?, Tatjana; Ili?, Nataša; Stepani?, Višnja; Sappe, Lana; Petranovi?, Jasna; Kraljevi? Paveli?, Sandra; Rai?-Mali?, Silvana

2014-07-01

165

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

166

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.

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

167

O Alkylation of a lignite humic acid by phase-transfer catalysis  

Microsoft Academic Search

A mild phase-transfer catalytic reaction has been conducted to O-alkylate the acidic functions of a lignite humic acid (HA), using tetrabutylammonium hydroxide as the phase-transfer catalyst.\\u000a The HA acidic functional groups were made to react, in tetrahydrofuran, by nucleophilic substitution with several alkyl halides—methyl\\u000a iodide, and ethyl, propyl, and butyl, and benzyl bromide. The occurrence of the O-alkylation reaction was

A. Piccolo; P. Conte; A. F. Patti

2006-01-01

168

Cellular and in vivo hepatotoxicity caused by green tea phenolic acids and catechins  

Microsoft Academic Search

Tea phenolic acids and catechins containing gallic acid moieties are most abundant in green tea, and various medical benefits have been proposed from their consumption. In the following, the cytotoxicities of these major tea phenolics toward isolated rat hepatocytes have been ranked and the mechanisms of cytotoxicity evaluated. The order of cytotoxic effectiveness found was epigallocatechin-3-gallate > propyl gallate > epicatechin-3-gallate > gallic acid, epigallocatechin > epicatechin. Using

Giuseppe Galati; Alison Lin; Amira M. Sultan; Peter J. O'Brien

2006-01-01

169

Mechanism of inhibition of tannic acid and related compounds on the growth of intestinal bacteria.  

PubMed

Tannic acid, propyl gallate and methyl gallate, but not gallic acid, were found to be inhibitory to the growth of intestinal bacteria Bacteroides fragilis ATCC 25285, Clostridium clostridiiforme ATCC 25537, C. perfringens ATCC 13124, C. paraputrificum ATCC 25780, Escherichia coli ATCC 25922, Enterobacter cloacae ATCC 13047, Salmonella typhimurium TA98 and S. typhimurium YG1041 at 100-1000 microg/ml in culture broth. Neither Bifidobacterium infantis ATCC 15697 nor Lactobacillus acidophilus ATCC 4356 was inhibited by any of the above compounds up to 500 microg/ml. Tannic acid has a much greater relative binding efficiency to iron than propyl gallate, methyl gallate or gallic acid. The inhibitory effect of tannic acid to the growth of intestinal bacteria may be due to the strong iron binding capacity of tannic acid; whereas the effect of propyl gallate and methyl gallate probably occurs by a different mechanism. The growth of E. coli was restored by the addition of iron to the medium after the precipitate caused by tannic acid was removed. Neither B. infantis nor L. acidophilus require iron for growth. This probably contributes to their resistance to tannic acid. Because tannins are abundant in the human diet, tannins may affect the growth of some intestinal bacteria and thus may have an impact on human health. PMID:9862646

Chung, K T; Lu, Z; Chou, M W

1998-12-01

170

Microorganisms hydrolyse amide bonds; knowledge enabling read-across of biodegradability of fatty acid amides.  

PubMed

To get insight in the biodegradation and potential read-across of fatty acid amides, N-[3-(dimethylamino)propyl] cocoamide and N-(1-ethylpiperazine) tall oil amide were used as model compounds. Two bacteria, Pseudomonas aeruginosa PK1 and Pseudomonas putida PK2 were isolated with N-[3-(dimethylamino)propyl] cocoamide and its hydrolysis product N,N-dimethyl-1,3-propanediamine, respectively. In mixed culture, both strains accomplished complete mineralization of N-[3-(dimethylamino)propyl] cocoamide. Aeromonas hydrophila PK3 was enriched with N-(1-ethylpiperazine) tall oil amide and subsequently isolated using agar plates containing dodecanoate. N-(2-Aminoethyl)piperazine, the hydrolysis product of N-(1-ethylpiperazine) tall oil amide, was not degraded. The aerobic biodegradation pathway for primary and secondary fatty acid amides of P. aeruginosa and A. hydrophila involved initial hydrolysis of the amide bond producing ammonium, or amines, where the fatty acids formed were immediately metabolized. Complete mineralization of secondary fatty acid amides depended on the biodegradability of the released amine. Tertiary fatty acid amides were not transformed by P. aeruginosa or A. hydrophila. These strains were able to utilize all tested primary and secondary fatty acid amides independent of the amine structure and fatty acid. Read-across of previous reported ready biodegradability results of primary and secondary fatty acid amides is justified based on the broad substrate specificity and the initial hydrolytic attack of the two isolates PK1 and PK3. PMID:24509885

Geerts, Roy; Kuijer, Patrick; van Ginkel, Cornelis G; Plugge, Caroline M

2014-07-01

171

Synthesis and evaluation of novel 4-[(3H,3aH,6aH)-3-phenyl)-4,6-dioxo-2-phenyldihydro-2H-pyrrolo[3,4-d]isoxazol-5(3H,6H,6aH)-yl]benzoic acid derivatives as potent acetylcholinesterase inhibitors and anti-amnestic agents.  

PubMed

The present study was designed to synthesize and evaluate pyrrolo-isoxazole benzoic acid derivatives as potential acetylcholinesterase (AChE) inhibitors for the management of Alzheimer's disease. The synthesis of pyrrolo-isoxazole benzoic acid derivatives involved ring opening cyclization of p-aminobenzoic acid with maleic anhydride to yield maleanilic acid, which in turn afforded N-arylmaleimide via ring closed cyclization. Azomethine-N-oxides were obtained by condensation of N-arylhydroxylamine with differently substituted benzaldehydes followed by refluxing of N-arylmaleimide with differently substituted azomethine-N-oxides to pyrrolo-isoxazole benzoic acid derivatives as cis- and trans-stereoisomers. The synthesized compounds were evaluated in vitro for AChE inhibitory activity in rat brain homogenate with donepezil as standard AChE inhibitor. Thereafter, the most potent test compound was evaluated for in vitro butyrylcholinesterase inhibitory activity and in vivo memory evaluation in scopolamine (0.4mg/kg)-induced amnesia in mice by employing Morris water maze test. All pyrrolo-isoxazole benzoic acid derivatives demonstrated potent AChE inhibitory activity. Most of compounds exhibited similar activity to donepezil and four of them (7h, 7i, 8i, and 8h, IC(50)=19.1±1.9-17.5±1.5nM) displayed higher inhibitory activity as compared to donepezil (21.5±3.2nM) with compound 8ia (IC(50)=17.5±1.5nM) being the most active one. The test compound 8ia also ameliorated scopolamine-induced amnesia in mice in terms of restoration of time spent in target quadrant (TSTQ) and escape latency time (ELT). It may be concluded that pyrrolo-isoxazole benzoic acid derivatives may be employed as potential AChE inhibitors. PMID:22172310

Anand, Preet; Singh, Baldev

2012-01-01

172

Bioadhesive analysis of controlled-release systems. I. Fracture and interpenetration analysis in poly(acrylic acid)-containing systems  

Microsoft Academic Search

Novel bioadhesive controlled release tablets were prepared from poly (acrylic acid) and hydroxy- propyl methylcellulose. Their bioadhesive behavior was studied in a modified tensile tester in contact with bovine sublingual mucus, and the force-elongation behavior was measured up to the breakpoint. The work of adhesion was calculated and related to bioadhesive characteristics of the tablets. It was found that the

Gilles Ponchel; Frederic Touchard; D DUCHENE; Nikolaos A. Peppas

1987-01-01

173

[Lipase-catalyzed production of biodiesel from high acid value waste oil with ultrasonic assistant].  

PubMed

Biodiesel fuel produced with the enzyme-catalyzed esterification and transesterification of high acid value waste oil through ultrasonic assistant was explored. Propyl oleate, biodiesel, converted from high acid value waste oil and 1-proponal catalyzed with immobilized lipases from Candida antarctica and Aspergillus oryzae in conditions of ultrasonic assistant. Commercial immobilized lipase Novozym 435 from C. antarctica was used as biocatalyst catalyzing high acid value waste oil and 1-proponal esterification and transesterification to propyl oleate under the ultrasonic assistant conditions and different conditions such as lipases amounts, initiatory molar ratio of propanol to oil, frequency of ultrasonic and power of ultrasonic were investigated and optimized. It is revealed that the enzymatic activity of Novozym435 is enhanced and, in particular, enzyme-catalyzed transesterification activity is enhanced obviously under the ultrasonic assistant conditions. Low frequency and mild energy ultrasonic is a key factor for enhancing enzymatic activity, emulsifying oil-propanol system and accelerating the speed of produce diffusing in the system. Under the optimal ultrasonic assistant reaction conditions, such as Novozym435 amounts 8% by oil quantity, initiatory molar ratio of propanol to oil 3:1, frequency of ultrasonic 28 KHz, power of ultrasonic 100 W and temperature of water batch 40-45 degrees C, the conversion ratio to propyl oleate reached to 94.86% in 50 mins in comparison with the highest conversion ratio to propyl oleate 84.43% under the conventional mechanical agitation conditions. Furthermore, it is demonstrated that various short chain linear and branched alcohols (C1-C5) show high conversion ratio to fatty acid alkyl esters (biodiesel) under the optimal ultrasonic assistant reaction conditions. On the other hand, ultrasonic energy is propitious to reduce the adsorption of product propyl oleate, by-product glycerol and other emplastics in system on the surface of immobilized lipase Novzym435 and recyclable Novozym435 possess clean appearances, well decentralizations, no agglomeration and easy washing and well operational stability. PMID:18257248

Wang, Jian-Xun; Huang, Qing-De; Huang, Feng-Hong; Wang, Jiang-Wei; Huang, Qin-Jie

2007-11-01

174

Immobilized hyaluronic acid containing model silicone hydrogels reduce protein adsorption  

Microsoft Academic Search

The physical immobilization of hyaluronic acid (HA) as a wetting agent in contact lens applications was investigated using model silicone hydrogels prepared by co-polymerizing methacryloxy propyl tris (trimethylsiloxy) silane (Tris) and hydroxyethylmethacrylate (HEMA). Two different molecular weights of HA were investigated, as well as various Tris\\/HEMA ratios. Cross-linked HA, while only present in small amounts, increased water uptake and hydrophilicity

Mark van Beek; Andrea Weeks; Heather Sheardown

2008-01-01

175

Detection of uric acid based on multi-walled carbon nanotubes polymerized with a layer of molecularly imprinted PMAA  

Microsoft Academic Search

A molecularly imprinted poly-methacrylic acid (PMAA), polymerizing on the surface of multi-walled carbon nanotubes (MWCNTs), was synthesized. The MWCNTs were modified by a layer of carboxylic acid and reacted with 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to activate the carboxylic acid, which was prepared for the purpose of bonding allyl amine and getting an unsaturated side chain (–CHCH2). The molecularly

Po-Yen Chen; Po-Chin Nien; Chih-Wei Hu; Kuo-Chuan Ho

2010-01-01

176

Analytical application of poly{methyl[3-(2-hydroxy-3,4-difluoro)phenyl]propyl siloxane} as a QCM coating for DMMP detection  

Microsoft Academic Search

A new material—poly{methyl[3-(2-hydroxy-3,4-difluoro)phenyl]propyl siloxane}(PMDFPS) sensitive to toxic organophosphate vapor was synthesized with 2,3-difluorophenol, allyl bromide and poly (methyl hydrosiloxane) as raw materials, via O-alkylation, Claisen rearrange reaction and hydrosilylation reaction. This novel material was then coated on a quartz crystal microbalance (QCM) to investigate its gas sensitive properties to the nerve agent simulant dimethyl methylphosphonate (DMMP) vapor, as well as

Wei He; Zhongxiang Liu; Xiaosong Du; Yadong Jiang; Dan Xiao

2008-01-01

177

Topical Drug Delivery from Thin Applications: Theoretical Predictions and Experimental Results  

Microsoft Academic Search

Stainless-steel templates of various thicknesses (75, 200, 800, and 1600 µm) were used to apply propylene glycol\\/water gels containing methyl or propyl p-aminobenzoates to silicone rubber membranes, and drug delivery was studied with the use of the Bronaugh diffusion cell under conditions in which the drug was initially in thermodynamic equilibrium with respect to the application and membrane. Theoretical diffusion

William Addicks; Norman Weiner; Gordon Flynn; Rane Curl; Elizabeth Topp

1990-01-01

178

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

179

Physicochemical properties of N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide for sodium metal battery applications.  

PubMed

The physicochemical properties of a range of NaNTf2 (or NaTFSI) salt concentrations in N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (or C3mpyrFSI) ionic liquid were investigated by DSC, conductivity, cyclic voltammetry and diffusivity studies. Cyclic voltammetry indicated a stable sodium plating behavior with a current of 5 mA cm(-2) at 25 °C to 20 mA cm(-2) at 100 °C, along with high reversibility identifying this electrolyte as a possible candidate for sodium-ion or sodium metal battery applications. (23)Na NMR chemical shifts and spectral linewidths (FWHM) indicate a complex coordination of the Na(+) ion which is dependent on both temperature and salt concentration with an apparently stronger coordination to the NTf2 anion upon increasing the NaNTf2 concentration. Temperature dependent PFG-NMR diffusion measurements show that both FSI and NTf2 have a comparable behaviour although the smaller FSI anion is more diffusive. PMID:24824026

Yoon, Hyungook; Zhu, Haijin; Hervault, Aziliz; Armand, Michel; MacFarlane, Douglas R; Forsyth, Maria

2014-05-28

180

Hyperthermia Stress Activates Heat Shock Protein Expression via Propyl Isomerase 1 Regulation with Heat Shock Factor 1  

PubMed Central

Heat shock proteins (HSPs), which are members of the chaperone family of proteins, are essential factors for cellular responses to environmental stressors, such as hyperthermia, and are antiapoptotic. The transcription of HSPs is mainly controlled by heat shock transcription factor 1 (HSF1). In response to environmental stress, HSF1 forms a trimer, undergoes hyperphosphorylation, and is translocated to the nucleus. In this study, we show that upon heat shock treatment of cells, a WW domain-containing propyl-isomerase, PIN1, is able to colocalize to and associate with phospho-HSF1 at Ser326 in the nucleus via its WW domain. This interaction is required for the DNA-binding activity of HSF1 and is consistent with the lower induction of HSPs in PIN1-deficient cells. This function of PIN1 is further demonstrated by in vivo refolding and survival assays, which have shown that PIN1-deficient cells are temperature sensitive and develop apoptosis upon exposure to an environmental challenge. Moreover, the reduced levels of HSPs in PIN1-deficient cells resulted in less efficient refolding of denatured proteins. Based on our results, we propose a novel role for PIN1 whereby it acts as a stress sensor regulating HSF1 activity in response to stress on multiple levels through the transcriptional activation of stress response elements in embryonic fibroblast cells, tumor cells, and neurons.

Wang, Hsiu-Yu; Fu, Jimmy Chun-Ming; Lee, Yu-Cheng

2013-01-01

181

Stability of the complex BSA-6-propyl-2-thiouracil in the presence of Gu·HCl and urea  

NASA Astrophysics Data System (ADS)

Pathologic structure of albumin is present in blood of uremic or diabetic patients. The defective binding of albumin can cause, among others, inhibition of the metabolism of amphipathic hormones and the enhancement of the toxicity of drugs. We aim to show the alteration of the binding site of 6-propyl-2-thiouracil (PTU) in bovine serum albumin (BSA) in the presence of urea and guanidine hydrochloride. This study shows that PTU has the tendency to interact within the hydrophobic domain IIA or IB of serum albumin and to quench the fluorescence of tryptophanyl side chains by the static and collisional quenching mechanism. For the binding to the native protein, two classes of binding sites are seen. In the first one, the binding constant is equal to K bI-9.6×10 4 M -1, and in the second class, the binding constant is K bII-7.1×10 3 M -1. For the binding to the denaturated serum albumin, only one class of the binding sites can be observed. The binding constants for BSA denatured with urea and Gu·HCl are lower and are equal to 2.2×10 4 M -1 and 3.5×10 4 M -1, respectively. Evaluation of the binding ability of serum albumin is also important in case of older people because weaker drug-protein interaction can result in the increase of drug concentration in the blood serum.

Równicka, Joanna; Su?kowska, Anna; Po?ycka, Jadwiga; Bojko, Barbara; Su?kowski, Wies?aw W.

2006-07-01

182

Induction of specific-locus and dominant lethal mutations in male mice by n-propyl and isopropyl methanesulfonate.  

PubMed

n-Propyl methanesulfonate (nPMS) and isopropyl methanesulfonate (iPMS) induce dominant lethal and specific-locus mutations in male mice. The response of the various spermatogenic stages to the induction of mutations differ markedly for nPMS and iPMS. Independent of the effective dose range the induction of dominant lethal mutations by nPMS is limited to spermatozoa and spermatids. In contrast, the induction of dominant lethal mutations by nPMS is limited to spermatozoa and spermatids. In contrast, the induction of dominant lethal mutations by iPMS is dose dependent: a dose of 20 mg iPMS/kg body weight (bw) is active only in spermatocytes, while a dose of 100 mg/kg bw induces dominant lethal mutations in all postspermatogonial germ cell stages. One other striking difference in the biological effectiveness of both compounds is that iPMS induces a sterile phase in stem-cell spermatogonia, whereas nPMS treated males even at the highest dose are fully fertile. PMID:7898506

Ehling, U H; Neuhäuser-Klaus, A

1995-04-01

183

Hyperthermia stress activates heat shock protein expression via propyl isomerase 1 regulation with heat shock factor 1.  

PubMed

Heat shock proteins (HSPs), which are members of the chaperone family of proteins, are essential factors for cellular responses to environmental stressors, such as hyperthermia, and are antiapoptotic. The transcription of HSPs is mainly controlled by heat shock transcription factor 1 (HSF1). In response to environmental stress, HSF1 forms a trimer, undergoes hyperphosphorylation, and is translocated to the nucleus. In this study, we show that upon heat shock treatment of cells, a WW domain-containing propyl-isomerase, PIN1, is able to colocalize to and associate with phospho-HSF1 at Ser(326) in the nucleus via its WW domain. This interaction is required for the DNA-binding activity of HSF1 and is consistent with the lower induction of HSPs in PIN1-deficient cells. This function of PIN1 is further demonstrated by in vivo refolding and survival assays, which have shown that PIN1-deficient cells are temperature sensitive and develop apoptosis upon exposure to an environmental challenge. Moreover, the reduced levels of HSPs in PIN1-deficient cells resulted in less efficient refolding of denatured proteins. Based on our results, we propose a novel role for PIN1 whereby it acts as a stress sensor regulating HSF1 activity in response to stress on multiple levels through the transcriptional activation of stress response elements in embryonic fibroblast cells, tumor cells, and neurons. PMID:24126052

Wang, Hsiu-Yu; Fu, Jimmy Chun-Ming; Lee, Yu-Cheng; Lu, Pei-Jung

2013-12-01

184

Gold nanoparticles incorporated 3-(trimethoxysilyl)propyl methacrylate modified electrode for non-enzymatic electro-sensing of urea.  

PubMed

We describe non-enzymatic electrochemical sensor for urea based on the electrocatalytic activity of gold nanoparticle (AuNPs) incorporated in 3-(Trimethoxysilyl)propyl methacrylate (TMSPMA) network. AuNPs incorporated in TMSPMA network on poly crystalline gold electrode show excellent electrocatalytic activity towards urea sensing. Uniform distribution and interaction of Au nanoparticles in nanospace of TMSPMA network are probably the key factors for catalytic effect of the nanocomposite. Nanocomposite is characterized by UV-visible diffuse reflectance spectroscopy, cyclic voltammetry, field emission scanning electron microscopy and X-ray photoelectron spectroscopy before using as urea sensor. The sensing platform is found to be highly sensitive and shows linear response in wide range for urea concentration with a sensitivity of 1.13 microA/microM and limit of detection as 2.08 microM respectively at S/N (signal-to-noise ratio): 3. It is also observed that the sensor does not suffer interference from phosphate and sulphate ions. Further, a possible mechanism for electro-sensing of urea with modified electrode has also been proposed. PMID:24734691

Gupta, Sandeep; Tiwari, Madhu; Prakash, Rajiv

2014-04-01

185

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

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

2012-01-01

186

Products of the OH radical-initiated reactions of 2-propyl nitrate, 3-methyl-2-butyl nitrate and 3-methyl-2-pentyl nitrate  

NASA Astrophysics Data System (ADS)

In the atmosphere, alkyl nitrates formed from the reactions of alkyl peroxy radicals with NO are chemically removed by photolysis and by reaction with OH radicals. Products of the gas-phase reactions of OH radicals with 2-propyl nitrate, 3-methyl-2-butyl nitrate and 3-methyl-2-pentyl nitrate at room temperature have been investigated. The products observed and quantified were: from 2-propyl nitrate, acetone (58 ± 18%); from 3-methyl-2-butyl nitrate, acetaldehyde (113 ± 39% from gas chromatographic analyses and 70 ± 25% from FT-IR analyses), acetone (55 ± 8%), and 3-methyl-2-butanone (17 ± 2%); and from 3-methyl-2-pentyl nitrate, acetaldehyde (120 ± 26% from gas chromatographic analyses and 80 ± 21% from FT-IR analyses), propanal (?1.1%), 2-butanone (33 ± 3%), 2-methylbutanal (?1.1%), and 3-methyl-2-pentanone (9 ± 1%), where the percentage molar yields are given in parentheses. Using these measured product yields together with predicted reaction schemes indicates that these products account for 58 ± 18%, 86 ± 15% and 63 ± 7% of the overall reaction pathways of the 2-propyl nitrate, 3-methyl-2-butyl nitrate and 3-methyl-2-pentyl nitrate reactions, respectively. The NO 2 present in the -ONO 2 group in these nitrates will be released in the reaction pathways leading to the observed products.

Aschmann, Sara M.; Tuazon, Ernesto C.; Arey, Janet; Atkinson, Roger

2011-03-01

187

The effect of novel [3-fluoro-(2-phosphonoethoxy)propyl]purines on the inhibition of Plasmodium falciparum, Plasmodium vivax and human hypoxanthine-guanine-(xanthine) phosphoribosyltransferases.  

PubMed

Protozoan parasites from the Plasmodiidae family are the causative agents of malaria. Inhibition of hypoxanthine-guanine-(xanthine) phosphoribosyltransferase (HG(X)PRT) has been suggested as a target for development of new anti-malarial therapeutics. Acyclic nucleoside phosphonates (ANPs) are potent and selective inhibitors of plasmodial HG(X)PRTs. A new series of ANPs, based on the chemical structure and inhibitory activity of three ANPs, 2-(phosphonoethoxy)ethyl with either guanine or hypoxanthine as the base (PEEG and PEEHx) and 3-hydroxy-2-(phosphonomethoxy)propyl with guanine as the base (HPMPG), were prepared. These compounds are stereoisomers of 3-fluoro-(2-phosphonoethoxy)propyl (FPEPs) and 3-fluoro-(2-phosphonomethoxy)propyl (FPMPs) analogues. Both the (R)- and (S)-isomers of these fluorinated derivatives have higher Ki values (by 10- to 1000-fold) for human HGPRT and Plasmodium falciparum HGXPRT than the non-fluorinated ANPs. Possible explanations for these changes in affinity are proposed based on docking studies using the known crystal structures of human HGPRT in complex with PEEG. PMID:23850568

Baszczy?ski, Ond?ej; Hocková, Dana; Janeba, Zlatko; Holý, Antonín; Jansa, Petr; Dra?ínský, Martin; Keough, Dianne T; Guddat, Luke W

2013-09-01

188

Decreased Bilirubin-Binding Capacity in Uremic Serum Caused by an Accumulation of Furan Dicarboxylic Acid  

Microsoft Academic Search

In chronic renal failure, substances that are effectively excreted in healthy subjects accumulate in serum. These substances, uremic toxins, include a variety of organic acids. It has been reported that a decrease in the bilirubin (BR) binding capacity occurs in the serum of renal failure patients. 3-Carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) has a high affinity for human serum albumin (HSA) and is

Yasuhiro Tsutsumi; Toru Maruyama; Akira Takadate; Hidekata Shimada; Masaki Otagiri

2000-01-01

189

Langmuir films from n -alkyl substituted 5'-phenyl- m -terphenyl carboxylic acids  

Microsoft Academic Search

We report studies on the influence of the introduction of an n-alkyl group in the 4? position of an aromatic carboxylic acid (namely 5?-phenyl- m-terphenyl-4-carboxylic acid, PTCA). For this purpose, 4?-methyl and 4?- n-propyl PTCA were synthesized and investigated at the air\\/water interface. The monolayers were characterized by measuring the surface pressure and electric surface potential upon film compression. The

Katarzyna Kita; Piotr Milart; D. A. S. Filho

190

Efficient Removal of Albumin-Bound Furancarboxylic Acid by Protein-Leaking Hemodialysis  

Microsoft Academic Search

Furancarboxylic acid (3-carboxy-4-methyl-5-propyl-2-furanpropionic acid, CMPF), an inhibitor of erythropoiesis, cannot be removed by conventional hemodialysis due to its strong albumin binding, resulting in its accumulation in uremic serum. We used protein-leaking hemodialysis with BK-F dialyzers in 8 uremic patients for 4 months to determine its effect on the serum levels of CMPF. Pre-hemodialysis serum levels of CMPF significantly decreased to

Toshimitsu Niwa; Hiroaki Asada; Shuichi Tsutsui; Takashi Miyazaki

1995-01-01

191

Morphology and water resistance of mixed silane films of bis[3-(triethoxysilyl) propyl]tetrasulfide and bis-[trimethoxysilylpropyl]amine  

SciTech Connect

Functional organosilanes are powerful interface-active agents that find applications as adhesion promoters as well as optical, dielectric and protective coatings. Bis-silanes are of particular interest because they are highly crosslinked leading to very robust films. In almost all applications, the water resistance of the films is a critical performance measure. Here we use neutron reflectivity to address the effect of bridging group on the hydrothermal response of bis-silane films prepared using bis[3-(triethoxysilyl) propyl]tetrasulfide and bis-[trimethoxysilylpropyl]amine. Neat and mixed films are examined as-prepared, after exposure to water vapor and then in the re-dried state. The bridging group is the key factor that controls the morphology and water resistance of silane films. Although bis-sulfur silane is not as condensed as bis-amino silane, bis-sulfur swells less in water because of the hydrophobic nature of bridging group. The reflectivity of bis-sulfur silane film is reversible after room-temperature water conditioning but not at 80 C, indicating chemical alternation of the film at 80 C. The water resistance of mixed silane is roughly that of both components weighted by their volume fraction. But based on the enhanced shrinkage that occurs following water-vapor conditioning of the mixed film, condensation is accelerated in the mixed silane. Regarding the precursor solution, bis-amino silane may act as a catalyst in the hydrolysis of bis-sulfur silane leading to more silanols in the solution and further condensation in the film. Variation in the structure normal to the substrate is also examined by swelling the film with d-nitrobenzene, a non-reacting swelling agent.

Pan, Guirong; Schaefer, Dale W.; van Ooij, Wim J.; Kent, Michael S.; Majewski, Jaroslaw; Yim, Hyun (UCIN); (Sandia); (LANL)

2010-12-03

192

Pharmacokinetic study of (S)-(-)-2-(N-propyl-N-(2-thienylethyl)amino)-5-hydroxytetralin infusion in cynomolgus monkeys.  

PubMed

A pharmacokinetic study of the dopamine D2 receptor agonist (S)-(-)-2-(N-propyl-N-(2-thienylethyl)amino)-5-hydroxytetralin+ ++-HCl (N-0923) infused in female cynomolgus monkeys over a 4-h period was carried out at International Research and Development Corporation. The purpose of this study was to estimate the elimination half-life and elucidate the dose-clearance relationship in cynomolgus monkeys with a randomized three-way crossover intravenous (iv) infusion study design. Six female cynomolgus monkeys were dosed by iv infusion for 4 h with 0.1, 0.5, and 1.0 mg/kg/h. Plasma samples were drawn during the infusion and up to 4 h post infusion. The plasma concentrations were determined by a sensitive and specific HPLC assay with electrochemical detection after solid-phase extraction at the Department of Toxicology and Bioanalysis at the University Center for Pharmacy in Groningen, The Netherlands. The plasma data were best described by a two-compartment open model. Mean elimination half-lives of 36.8, 39.6, and 52.4 min and mean clearance values of 229 +/- 35, 202 +/- 85, and 191 +/- 36 mL/min/kg were obtained for doses of 0.1, 0.5, and 1.0 mg/kg/h, respectively. The steady-state volumes of distribution were estimated as 3.89 +/- 0.816, 3.53 +/- 1.62, and 4.70 +/- 3.67 L/kg for the same doses, respectively. There were no significant differences between any of the estimated pharmacokinetic parameters for any of the infusion doses. Clearance was not dose dependent and steady-state plasma concentration appeared directly proportional to dose, suggesting linear pharmacokinetics in this dose range for monkeys. PMID:7915310

Walters, D R; McConnell, W R; Cefali, E A

1994-05-01

193

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

PubMed

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 pA 2 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

2012-10-01

194

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

195

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

196

Photophysical Properties of Lanthanide Hybrids Covalently Bonded To Functionalized MCM-41 by Modified Aromatic Carboxylic Acids  

Microsoft Academic Search

MCM-41 mesoporous silica has been functionalized with aromatic carboxylic acids salicylic acid (Sal) and 2-hydroxyl-3-methylbenzoic\\u000a acid (HMBA) through co-condensation approach of tetraethoxysilane (TEOS) in the presence of the cetyltrimethylammonium bromide\\u000a (CTAB) surfactant as a template. Organic ligands salicylic acid or 2-hydroxyl-3-methylbenzoic acid grafted to the coupling\\u000a agent 3-(triethoxysilyl)-propyl isocyanate (TEPIC) was used as the precursor for the preparation of an

Ying Li; Bing Yan

2009-01-01

197

Effects of polytherapy with phenytoin, carbamazepine, and stiripentol on formation of 4-ene-valproate, a hepatotoxic metabolite of valproic acid  

Microsoft Academic Search

The incidence of valproic acid hepatotoxicity has been reported to increase in patients who are receiving polytherapy. A minor valproic acid metabolite, 2-propyl-4-pentenoic acid (4-ene-VPA), formed by a cytochrome P450-mediated reaction, has been shown to be a potent inducer of microvesicular steatosis in rats. This study tested the hypothesis that formation of 4-ene-VPA would be increased in patients taking valproic

René H Levy; Albert W Rettenmeier; Gail D Anderson; Alan J Wilensky; Patrick N Friel; Thomas A Baillie; Andrew Acheampong; Jacques Tor; Martine Guyot; Pierre Loiseau

1990-01-01

198

Cyclopropane amino acid ester dipeptide sweeteners.  

PubMed

A series of esters of L-aspartyl-1-aminocyclopropane carboxylic acid has been prepared and their sweet tastes determined. The sweetest ester prepared was about 300 times sweeter than sucrose. An attempt to use basic conditions during preparation of the dipeptide allyl ester led to succinimide formation of the aspartyl peptide even though the beta-carboxyl group was protected by a t-butyl ester function. The X-ray structure of the propyl ester (1c) was determined and its conformation is discussed. PMID:3429129

Mapelli, C; Newton, M G; Ringold, C E; Stammer, C H

1987-10-01

199

Bis(3,5-dimethyl-pyrazolyl-1-methyl)-(3-phosphanyl-propyl)-amine complexes of copper(II), nickel(II), and cobalt(II)  

Microsoft Academic Search

A series of Cu(II), Co(II), and Ni(II) complexes of bis-(3,5-dimethyl-pyrazolyl-1-methyl)-(3-phosphanyl-propyl)-amine C15H26N5P (1), prepared from 3-aminopropylphosphine and 1-hydroxymethyl-3,5-dimethylpyrazole were characterized. The nature of bonding and the geometry of the complexes have been deduced from elemental analysis, infrared, electronic, H NMR, P NMR spectra, magnetic susceptibility, and conductivity measurements. The studies indicate octahedral geometry for nickel complex and square pyramidal geometry for

P. Tharmaraj; D. Kodimunthiri; C. D. Sheela; P. Prakash

2009-01-01

200

Rate constants for the reaction of OH radicals with n-propyl, n-butyl, iso-butyl and tert-butyl vinyl ethers  

Microsoft Academic Search

Rate constants for the reaction of OH radicals with n-propyl vinyl ether (PVE, CH3CH2CH2OCHCH2), n-butyl vinyl ether (BVE, CH3CH2CH2CH2OCHCH2), iso-butyl vinyl ether (IBVE, (CH3)2CHCH2OCHCH2) and tert-butyl vinyl ether (TBVE, (CH3)3COCHCH2), have been measured in the temperature and pressure ranges 232–373K and 30–300Torr using the pulsed laser photolysis-laser-induced fluorescence method, and at 298K and 760Torr using the relative method. The obtained

G. Thiault; A. Mellouki

2006-01-01

201

Bis(?2-iso-propyl-imido-?2 N:N)bis-[(?5-cyclo-penta-dien-yl)(ethenolato-?O)titanium(IV)  

PubMed Central

The title dinuclear half-sandwich complex, [CpTi(OCH=CH2)(?2-N-iPr)]2 (Cp = cyclo­penta­dien­yl; iPr = isopropyl), was ob­tained from the reaction of Cp2TiCl2, n-butyl­lithium and iso­propyl­amine in tetra­hydro­furan. Each TiIV atom is coordinated by one Cp ligand, one vin­yloxy unit and two bridging imido groups in a strongly distorted tetra­hedral geometry. There are two half mol­ecules in the asymmetric unit, such that whole mol­ecules being generated by inversion symmetry.

Haehnel, Martin; Spannenberg, Anke; Rosenthal, Uwe

2014-01-01

202

Heat of Mixing and Solution of Propyl propanoate C6H12O2 + C7H8 Toluene (HMSD1111, LB4186_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 propanoate C6H12O2 + C7H8 Toluene (HMSD1111, LB4186_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.

203

CCR5 antagonists as anti-HIV-1 agents. Part 2: Synthesis and biological evaluation of N-[3-(4-benzylpiperidin-1-yl)propyl]- N, N ?-diphenylureas  

Microsoft Academic Search

We have previously reported the novel lead compound 1a as a CCR5 antagonist for treatment of HIV-1 infection. SAR studies on incorporating various acyl groups as a replacement for the 5-oxopyrrolidine-3-carbonyl group of the lead structure resulted in the discovery of N-[3-(4-benzylpiperidin-1-yl)propyl]-N,N?-diphenylurea (4a) with significantly improved CCR5 binding affinity. Substitutions (4-Cl, 4e,f; 4-Me, 4i) on the N?-phenyl ring further increased

Shinichi Imamura; Osamu Kurasawa; Yoshi Nara; Takashi Ichikawa; Youichi Nishikawa; Takehiro Iida; Shohei Hashiguchi; Naoyuki Kanzaki; Yuji Iizawa; Masanori Baba; Yoshihiro Sugihara

2004-01-01

204

Solid-state 1H NMR in 1-propyl-1H-tetrazole complexes of iron(II) and zinc(II)  

NASA Astrophysics Data System (ADS)

PMR linewidths (??) and spin-lattice relaxation times ( T1) were measured on [M(1- n-propyl-1H-tetrazole) 6](BF 4) 2 (M is Zn or Fe). Three motional minima of T1 associated with steps of ?? were found, and a structural change in the temperature region of 100 to 120 K is suggested in the zinc complex. The spin transition temperature was found to be ˜130 K, and an anomalous minimum of T1 occurred at 9 K in the iron complex.

Bokor, Mónika; Marek, Tamás; Tompa, Kálmán; Vértes, Attila

1997-06-01

205

Synthesis and characterization of a new surface derivatizing reagent to promote the adhesion of polypyrrole films to n-type silicon photoanodes: N-(3-(trimethoxysilyl)propyl) pyrrole  

SciTech Connect

The synthesis, characterization, and application of N-(3-(trimethoxysilyl-propyl)pyrrole (I) as a photoanode derivatizing reagent that can be covalently anchored to the electrode via reaction of surface OH groups are described. The pendant group of I can then be used as the initiation site for polymerization of polypyrrole. The treatment of both Pt and n-type Si electrodes with I and films of polypyrrole to protect the semiconductor from photoanodic decomposition is described. Improved durability noted for the treated n-type Si electrodes is attributed to less H/sub 2/O/electrolyte undermining of the polymer when it is covalently anchored to the surface. (BLM)

Simon, R.A.; Ricco, A.J.; Wrighton, M.S.

1982-04-07

206

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

207

Direct evidence for preferential {beta} C-H bond cleavage resulting from 248 nm photolysis of the n-propyl radical using selectively-deuterated 1-bromopropane precursors  

SciTech Connect

A series of selectively deuterated 1-bromopropane precursors have been used to study site-specific photolysis in the n-propyl radical. A two-color photolysis approach (222 nm followed by 248 nm radiation) is used to create an intermediate photofragment and produce an H or a D atom, which is detected by 1 + 1 resonance ionization through Lyman-{alpha}. Target precursors are BrCH{sub 2}CD{sub 2}CD{sub 3}, BrCD{sub 2}CH{sub 2}CD{sub 3}, and BrCD{sub 2}CD{sub 2}CH{sub 3} as well as BrCD{sub 2}CH{sub 2}CH{sub 3}, BrCH{sub 2}CD{sub 2}CH{sub 3}, and BrCH{sub 2}CH{sub 2}CD{sub 3}. The `enhanced` H (or D) atom signals clearly demonstrate that C-H (or C-D) bond cleavage at the {beta} position is strongly favored. The net enhancement process undoubtedly involves photolysis of an intermediate, almost certainly the n-propyl radical. A comparison with systems involving ethyl and isopropyl radical photolysis is also presented. 14 refs., 4 figs.

Wang, Z.; Mathews, M.G.; Koplitz, B. [Tulane Univ., New Orleans, LA (United States)

1995-05-04

208

Silica chemically bonded N-propyl kriptofix 21 and 22 with immobilized palladium nanoparticles for solid phase extraction and preconcentration of some metal ions.  

PubMed

Silica gel chemically bonded N-propyl kriptofix 21 (SBNPK 21) and N-propyl kriptofix 22 (SBNPK 22) and subsequently immobilized with palladium nanoparticles (PNP-SBNPK 21 and PNP-SBNPK 22) to produce two new complexing lipophilic materials. Then these novel sorbents were applied for the enrichment of some metal ions and their subsequent determination by flame atomic absorption spectroscopy (FAAS). The influences of the variables including pH, amount of solid phase, sample flow rate, eluent conditions and sample volume on the metal ion recoveries were investigated. The detection limit of proposed method was in the interval 2.1-2.3 and 1.7-2.8 ng mL(-1) for PNP-SBNPK 21 and PNP-SBNPK 22 respectively, while the preconcentration factor was 80 for two sorbents. The relative standard deviations of recoveries were between 1.23-1.31 and 1.28-1.49 for PNP-SBNPK 21 and PNP-SBNPK 22 respectively. The method has high sorption-preconcentration efficiency even in the presence of various interfering ions. Due to the reasonable selectivity of proposed method, the relative standard deviation of recoveries of all understudied metal ions in some complicated matrices was less than 3.0%. PMID:23706199

Ghaedi, Mehrorang; Niknam, Khodabakhsh; Zamani, Saeed; Larki, Habib Abasi; Roosta, Mostafa; Soylak, Mustafa

2013-08-01

209

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

210

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, N 2 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

211

The carboxyl modifier 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide (EDC) inhibits half of the high-affinity Mn-binding site in photosystem II membrane fragments  

SciTech Connect

The diphenylcarbazide (DPC)/Mn{sup 2+} assay was used to assess the amount of the high-affinity Mn-binding site in manganese-depleted photosystem II (PS II) membrane fragments from spinach and Scenedesmus obliquus. The assay mechanism at high DPC concentration was shown to involve noncompetitive inhibition of only half of the control level of DPC donation to PS II by micromolar concentrations of Mn at pH 6.5. At low DPC concentration both DPC and Mn{sup 2+} donate to PS II additively. Treatment with the carboxyl amino acid modifier 1-ethyl-3-(3(dimethylamino) propyl) carbodiimide (EDC) inhibited half of the high affinity Mn-binding site in spinach and Scenedesmus WT PS II membranes and all of the available site in Scenedesmus LF-1 mutant PS II membranes. A similar EDC concentration dependence was observed in all cases. This protection was specific for Mn{sup 2+}; six other divalent cations were ineffective. The authors conclude that EDC modifies that half of the high-affinity Mn-binding site that is insensitive to the histidine modifier diethyl pyrocarbonate (DEPC) and directly affects ligands that bind Mn. The effects of EDC and DEPC that influence the high-affinity site are mutually exclusive and are specific to the lumenal side of the PS II membrane. They suggest that carboxyl residues on reaction center proteins are associated with half of the high-affinity Mn-binding site in PS II and are involved along with histidine residues in binding Mn functional in the O{sub 2}-evolving process.

Preston, C.; Seibert, M. (Solar Energy Research Inst., Golden, CO (United States))

1991-10-08

212

Precombustion of fatty acids and esters of biodiesel. A possible explanation for differing cetane numbers  

Microsoft Academic Search

Fatty acids of C18 chainlength as well as their methyl, ethyl, n-propyl, and n-butyl esters were injected into a constant-volume combustion apparatus suitable for collecting material from the fuel spray\\u000a prior to the onset of ignition. The collected material from this precombustion phase of the injection event was analyzed by\\u000a gas chromatography-mass spectrometry. Compounds identified as forming during the precombustion

Gerhard Knothe; Marvin O. Bagby; Thomas W. Ryan

1998-01-01

213

HPLC Determination of 6-Thiouric Acid and 6Mercaptopurine in Organ Transplant Patient Serum  

Microsoft Academic Search

A sensitive high performance liquid chromatographic method for the simultaneous determination of 6-thiouric acid and 6-mercaptopurine in serum is described. Our intent was to develop a procedure that could be used for pharmacokinetic studies and therapeutic drug monitoring in organ transplant patients taking azathioprine. Serum samples were precipitated with acetonitrile containing 6-n-propyl-2-thiouracil as the internal standard. The chromatographic separation was

Gary R. Erdmann; Gary L. C. Chan; Daniel M. Canafax

1988-01-01

214

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

215

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

216

Excess molar enthalpies for the binary and ternary mixtures of ether compounds ( di -isopropyl ether, di -butyl ether, propyl vinyl ether) with ethanol and isooctane at 298.15 K  

Microsoft Academic Search

Excess molar enthalpy (H\\u000a E\\u000a ) data at 298.15 K are reported for the binary systems di-isopropyl ether (1)+ethanol (2), di-isopropyl ether (1)+isooctane (2), ethanol (1)+isooctane (2), di-butyl ether (1)+ethanol (2), di-butyl ether (1)+isooctane (2), propyl vinyl ether (1)+ethanol (2) and propyl vinyl ether (1)+isooctane (2). These data were\\u000a obtained by using an isothermal flow calorimeter. The experimental binary H

Moon-Gab Kim; So-Jin Park; In-Chan Hwang

2008-01-01

217

Diastereoselective reduction of 1-(4-fluorophenyl)-3(R)-[3-oxo-3-(4-fluorophenyl)-propyl]-4(S)-(4-hydroxyphenyl)azetidin-2-one to Ezetimibe by the whole cell catalyst Rhodococcus fascians MO22  

Microsoft Academic Search

The asymmetric microbial reduction of 1-(4-fluorophenyl)-3(R)-[3-oxo-3-(4-fluorophenyl)-propyl]-4(S)-(4-hydroxyphenyl)azetidin-2-one to 1-(4-fluorophenyl)-3(R)-[3(S)-hydroxy-3-(4-fluorophenyl)-propyl]-4(S)-(4-hydroxyphenyl)azetidin-2-one (Ezetimibe) by Rhodococcus fascians MO22 is described. The catalytic capability of the microorganism for reduction has been examined also with protected ketone, an intermediate from chemical synthesis of Ezetimibe. Various parameters of the bioreduction have been optimized: the strain converted 94.8% of ketone and 63% of protected ketone into Ezetimibe with the

Eva Kyslíková; Peter Babiak; Helena Marešová; Andrea Palyzová; Josef Hájí?ek; Pavel Kyslík

2010-01-01

218

Boronic acid-facilitated alpha-hydroxy-carboxylate anion transfer at liquid\\/liquid electrode systems: the EIC(rev) mechanism  

Microsoft Academic Search

The transfer of the alpha-hydroxy-carboxylates of glycolic, lactic, mandelic and gluconic acid from the aqueous electrolyte phase into an organic 4-(3-phenyl-propyl)-pyridine (PPP) phase is studied at a triple-phase boundary electrode system. The tetraphenylporphyrinato complex MnTPP dissolved in PPP is employed to drive the anion transfer reaction and naphthalene-2-boronic acid (NBA) is employed as a facilitator. In the absence of a

F. Marken; N. Katif; R. A. Harries; A. M. Kelly; J. S. Fossey; T. D. James

2009-01-01

219

Intramolecular and intermolecular migration of propyl groups in 9-isopropyl-o- and 9-isopropyl-m-carboranes under the action of HCl and AlCl/sub 3/  

SciTech Connect

Under the action of HCl and AlCl/sub 3/ intramolecular and intermolecular migration of propyl groups occurred in 9-isopropyl-o-carborane and 9-isopropyl-m-carborane in CS/sub 2/ at 20/sup 0/C which was accompanied by isomerization of isopropyl groups into propyl. The action of AlCl/sub 3/ and HCl on 9-isopropyl-o-carborane led to o-carborane, a mixture of disubstituted B,B'-(C/sub 3/H/sub 7/)/sub 2/-o-carboranes, and a mixture of monosubstituted B-(C/sub 3/H/sub 7/)-o-carboranes which consisted of 4-, 8-, and 9-isopropyl-, and 8- and 9-propyl-o-carboranes. On reacting HCl and AlCl/sub 3/ with 9-isopropyl-m-carborane there was formed m-carborane, a mixture of disubstituted B,b'-(C/sub 3/H/sub 7/)/sub 2/-m-carboranes, and a mixture of monosubstituted B-(C/sub 3/H/sub 7/)-m-carboranes consisting of 4-, 5-, and 9-isopropyl-m-, and -, 5-, and 9-propyl-m-carboranes.

Zakharkin, L.I.; Kovredov, A.I.; Ol'shevskaya, V.A.; Vitt, S.V.

1986-04-20

220

Biological activity of volatile di-n-propyl disulfide from seeds of neem, Azadirachta indica (Meliaceae), to two species of stored grain pests, Sitophilus oryzae (L.) and Tribolium castaneum (Herbst).  

PubMed

Head space volatiles, including 73% di-n-propyl disulfide, were collected from freshly crushed neem seeds. This compound along with previously reported diallyl disulfide (di-2-propenyl disulfide) were toxic when applied topically or as a fumigant to Tribolium castaneum adults and 8-, 12-, and 16-d-old larvae, and Sitophilus oryzae adults. Di-n-propyl disulfide significantly decreased the growth rate and dietary utilization with moderate inhibition of food consumption in both insects. The total coefficient of deterrence for this compound ranged between 68.5 and 178.6, which suggests that it has medium to very good deterrent activity vis-à-vis the treatment concentration and instar. Di-n-propyl disulfide and diallyl disulfide presented a similar effect on efficiency of conversion of ingested food, which is reduced 3-fold; this implies that both compounds are physiological toxicants. Present studies clearly demonstrate that di-n-propyl disulfide could be a potent toxicant, fumigant, and feeding deterrent for stored grain pests, if a suitable formulation and application procedure are developed. PMID:15279303

Koul, Opender

2004-06-01

221

Diaqua-bis-(dihydrogen 3-aza-niumyl-1-hy-droxy-propyl-idene-1,1-di-phos-phon-ato-?2 O,O?)cobalt(II)  

PubMed Central

The asymmetric unit of title compound, [Co(C3H10NO7P2)2(H2O)2], contains one half-mol­ecule of the complex. The CoII atom is located on an inversion centre and displays a distorted octa­hedral coordination geometry defined by four O atoms of two 3-aza­niumyl-1-hy­droxy­propyl­idene-1,1-bis­phospho­nato ligands in the equatorial plane and two water mol­ecules located in axial positions. The ligand mol­ecules, which exist in a zwitterionic state, form two six-membered chelate rings with chair conformations. In the crystal, mol­ecules are inter­linked by O—H?O and N—H?O hydrogen bonds, forming a three-dimensional supra­molecular structure.

Tsaryk, Natalia V.; Dudko, Anatolij V.; Kozachkova, Alexandra N.; Pekhnyo, Vasily I.

2011-01-01

222

Thermodynamic phase transition through crystal-to-crystal process of photochromic 1,2-bis(5-phenyl-2-propyl-3-thienyl)perfluorocyclopentene.  

PubMed

A photochromic diarylethene, 1,2-bis(5-phenyl-2-propyl-3-thienyl)perfluorocyclopentene (1a), was found to have two polymorphic crystal forms, ?- and ?-crystals. From X-ray crystallographic analysis, the space groups of ?- and ?-crystals were determined to be P21 /c and C2/c, respectively. The difference between two crystal forms is ascribed to the orientation of two of four molecules in the unit cell. The thermodynamic phase transition from ?- to ?-forms occurred via a crystal-to-crystal process, as confirmed by differential scanning calorimetry measurements, optical microscopic observations in the reflection mode and under crossed Nicols, and powder X-ray diffraction measurements. The movement of the molecules in the crystal was evaluated by analyzing the change of face indices before and after the phase transition. PMID:24115495

Kitagawa, Daichi; Kobatake, Seiya

2014-01-01

223

Rapid separation of barbiturates and benzodiazepines by capillary electrochromatography with 3-(1,8-naphthalimido)propyl-modified silyl silica gel.  

PubMed

A capillary electrochromatographic (CEC) method was applied to the simultaneous separation of barbiturates (barbital, phenobarbital, secobarbital and thiopental) and benzodiazepines (nitrazepam, diazepam and triazolam). The separation was performed in a 75 microm i.d. capillary, packed with 3-(1,8-naphthalimido)propyl-modified silyl silica gel (NAIP), studying the effects of buffer pH and mobile phase composition. Using an applied voltage of 20 kV and the short-end injection method (9 cm capillary effective length), the mobile phase of 1.0 mM citrate buffer (pH 5.0) containing 45% methanol provided the baseline separation of seven toxic drugs in less than 9 min. In CEC with NAIP, the benzodiazepines were separated by the combination of hydrophobic and pi-pi interactions, whereas the separation of the barbiturates was based on the hydrophobic interaction. PMID:15273980

Ohyama, Kaname; Wada, Mitsuhiro; Ohba, Yoshihito; Fujishita, Osamu; Nakashima, Kenichiro; Kuroda, Naotaka

2004-07-01

224

CCR5 antagonists as anti-HIV-1 agents. Part 2: Synthesis and biological evaluation of N-[3-(4-benzylpiperidin-1-yl)propyl]-N,N'-diphenylureas.  

PubMed

We have previously reported the novel lead compound 1a as a CCR5 antagonist for treatment of HIV-1 infection. SAR studies on incorporating various acyl groups as a replacement for the 5-oxopyrrolidine-3-carbonyl group of the lead structure resulted in the discovery of N-[3-(4-benzylpiperidin-1-yl)propyl]-N,N'-diphenylurea (4a) with significantly improved CCR5 binding affinity. Substitutions (4-Cl, 4e,f; 4-Me, 4i) on the N'-phenyl ring further increased the binding affinity. Introduction of polar substituents on the phenyl ring of the 4-benzylpiperidine moiety enhanced the inhibitory activity of the HIV-1 envelope-mediated membrane fusion (4v,w), suggesting that polar substituents at this position can interfere effectively with HIV-1 cell entry. PMID:15080927

Imamura, Shinichi; Kurasawa, Osamu; Nara, Yoshi; Ichikawa, Takashi; Nishikawa, Youichi; Iida, Takehiro; Hashiguchi, Shohei; Kanzaki, Naoyuki; Iizawa, Yuji; Baba, Masanori; Sugihara, Yoshihiro

2004-05-01

225

Design, synthesis and applications of chiral N-2-phenyl-2-propyl sulfinyl imines for Group-Assisted Purification (GAP) asymmetric synthesis  

PubMed Central

A new chiral (Rs)-2-phenyl-2-propyl sulfinamide has been designed and synthesized; its derived aldimines and ketimines have been applied for asymmetric addition reaction with allylmagnesium bromide. The reaction was conveniently performed at room temperature to give a series of homoallylic amines in high yields (up to quant) and diastereoselectivity (up to >99 % de). The pure products were obtained by relying on Group-Assisted Purification (GAP) chemistry to avoid traditional purification methods of column chromatography or recrystallization. The conversion of disulfide to (Rs)-thiosulfinate was also confirmed to be of the GAP chemistry in which washing crude product can generate pure enantiomer. The absolute stereochemistry has been determined by X-ray analysis.

Pindi, Suresh; Wu, Jianbin; Li, Guigen

2013-01-01

226

Complexometric titration of thallium(III), by use of 4-amino-5-mercapto-3-propyl-1,2,4-triazole as replacing reagent.  

PubMed

A simple and selective EDTA method using a masking and demasking technique is proposed for the determination of thallium(III). The thallium is complexed with excess of EDTA, the surplus being back-titrated (pH 5-6, hexamine buffer) with zinc sulphate solution (Xylenol Orange as indicator). 4-Amino-5-mercapto-3-propyl-1,2,4-triazole is then added and the mixture heated on a water-bath for 5-10 min to displace EDTA from its thallium complex. The EDTA liberated is titrated with zinc sulphate solution. Reproducible and accurate results are obtained in the range 5-75 mg of thallium with both the relative error and coefficient of variation not exceeding 0.4%. PMID:18964601

Shetty A, N; Gadag, R V; Gajendragad, M R

1988-09-01

227

Preparation and evaluation of a silica-based 1-alkyl-3-(propyl-3-sulfonate) imidazolium zwitterionic stationary phase for high-performance liquid chromatography.  

PubMed

A new zwitterionic stationary phase based on silica bonded with 1-alkyl-3-(propyl-3-sulfonate) imidazolium was synthesized and characterized in this paper. The materials have been confirmed and evaluated by elemental analysis, thermogravimetric analysis and X-ray photoelectron spectroscopy. Potassium and calcium were separated simultaneously with several common inorganic anions including an iodate, chloride, bromide, nitrate and iodide on the phase. The effects of the concentration, organic solvent and pH of the eluent on the separation of anions were studied. Operated in the anion-exchange mode, this new stationary phase shows considerable promise for the separation of anions. Bases, vitamins and three imidazolium ionic liquids with different alkyl chains are also separated successfully on this column. The stationary phase has multiple retention mechanisms, such as anion-exchange, electrostatic attraction and repulsion interactions, and hydrophobic interaction between the zwitterionic stationary phase and specimens. PMID:17582425

Qiu, Hongdeng; Jiang, Qiong; Wei, Zheng; Wang, Xusheng; Liu, Xia; Jiang, Shengxiang

2007-09-01

228

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

229

Mechanism and dynamics of intramolecular triplet state decay of 1-propyl-4-thiouracil and its ?-methyl-substituted derivatives studied in perfluoro-1,3-dimethylcyclohexane.  

PubMed

The absorption, phosphorescence and phosphorescence excitation spectra, phosphorescence quantum yields, and T(1) excited state lifetimes of four 4-thiouracil derivatives were measured for the first time in chemically inert and very weakly interacting perfluoro-1,3-dimethylcyclohexane at room temperature. The set of the 4-thiouracil derivatives comprises 1-propyl-4-thiouracil (PTU) and the related compounds having a methyl substituent at the position ? to the thiocarbonyl group, namely 1-propyl-4-thiothymine (PTT), 1,3-dimethyl-4-thiouracil (DMTU), and 1-methyl-3-trideuteriomethyl-4-thiouracil ([D(3)]DMTU). Quantitative information on the intramolecular decay of the T(1) excited state of the four 4-thiouracil derivatives is presented, and the mechanism and dynamics of this process are discussed. In the absence of self quenching and solvent induced deactivation, the T(1) decay of the four 4-thiouracil derivatives was dominated by intramolecular nonradiative processes (NR). The values of the rate constant k(NR) in DMTU and [D(3)]DMTU are about 4 times larger than that in PTT and about 3 times larger than that in PTU. The reasons for the enhanced nonradiative rate constant in DMTU are discussed. It is concluded that the faster rate of the nonradiative processes in DMTU is related to a larger contribution from mixing of the T(2) (n?*) state into the lowest energy T(1) (??*) state, as compared to the analogous coupling in PTU and PTT. This conclusion is supported by ab initio calculations performed at the EOM-CC2/aug-cc-pVDZ level of theory. The energy spacing between the T(2) (n?*) and T(1) (??*) states is estimated to be about 500, 1100, and 2000 cm(-1) for DMTU, PTU, and PTT, respectively. Among the three compounds in question, the predicted energy spacing is thus the smallest for DMTU. PMID:21594285

Wenska, Grazyna; Taras-Go?li?ska, Katarzyna; ?ukaszewicz, Adam; Burdzi?ski, Gotard; Koput, Jacek; Maciejewski, Andrzej

2011-08-01

230

Surface modification of polycaprolactone with poly(methacrylic acid) and gelatin covalent immobilization for promoting its cytocompatibility  

Microsoft Academic Search

Polycaprolactone (PCL) membrane was modified by grafting copolymerization of methacrylic acid (MAA) initiated under UV light. The covalent immobilization of gelatin on PCL-g-PMAA surface was consequently performed by using condensing agent, 1-ethyl-3-(3-dimethylamino propyl) carbodiimide hydrochloride. The occurrence of grafting copolymerization of PMAA and further immobilization of gelatin was confirmed by ATR-FTIR and X-ray photoelectron spectroscopy characterizations. The existence of carboxyl

Yabin Zhu; Changyou Gao; Jiacong Shen

2002-01-01

231

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.

232

Synthesis of acetals and ketals catalyzed by tungstosilicic acid supported on active carbon.  

PubMed

Catalytic activity of activated carbon supported tungstosilicic acid in synthesizing 2-methyl-2-ethoxycarbonylmethyl- 1,3-dioxolane, 2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane, cyclohexanone ethylene ketal, cyclohexanone 1,2-propa- nediol ketal, butanone ethylene ketal, butanone 1,2-propanediol ketal, 2-phenyl-1,3-dioxolane, 4-methyl-2-phenyl-1,3-dioxolane, 2-propyl-1,3-dioxolane, 4-methyl-2-propyl-1,3-dioxolane was reported. It has been demonstrated that activated carbon supported tungstosilicic acid is an excellent catalyst. Various factors involved in these reactions were investigated. The optimum conditions found were: molar ratio of aldehyde/ketone to glycol is 1/1.5, mass ratio of the catalyst used to the reactants is 1.0%, and reaction time is 1.0 h. Under these conditions, the yield of 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane is 61.5%, of 2,4-dimethyl- 2-ethoxycarbonylmethyl-1,3-dioxolane is 69.1%, of cyclohexanone ethylene ketal is 74.6%, of cyclohexanone 1,2-propanediol ketal is 80.1%, of butanone ethylene ketal is 69.5%, of butanone 1,2-propanediol ketal is 78.5%, of 2-phenyl-1,3-dioxolane is 56.7%, of 4-methyl-2-phenyl-1,3-dioxolane is 86.2%, of 2-propyl-1,3-dioxolane is 87.5%, of 4-methyl-2-propyl-1,3-dioxolane is 87.9%. PMID:15822150

Yang, Shui-Jin; Du, Xin-Xian; He, Lan; Sun, Ju-Tang

2005-05-01

233

A validated spectrophotometric and liquid chromatography method for determination and purity evaluation of 4-methoxy-2-[2-hydroxy-3(4-phenyl-1-piperazinyl)]propyl-2,3-dihydro-6-methyl-1,3-dioxo-1H-pyrrolo[3,4-c]pyridine.  

PubMed

A spectrophotometric analysis of the UV-spectrum of 4-methoxy-2-[2-hydroxy-3(4-phenyl-1-piperazinyl)]propyl-2,3-dihydro-6-methyl-1,3-dioxo-1H-pyrrolo[3,4-c]pyridine (I) in 0.01 M HCl was performed by determining the values of specific absorption coefficients at the following analytical wavelengths: 224, 285 and 348 nm. The separation by means of TLC of compound I and of its five decomposition products was also studied. Silica gel coated plates (60 F(254)) were used and the mobile phase was consisted of butanol-acetic acid (1.05 kg/l)-water (80:12:30, v/v/v). The HPLC method (LiChrosorb(R) 100 RP-18 column 250 x 4.0 mm I.D., dp=5 microm; mobile phase: acetonitrile-0.01 M phosphate buffer (H(3)PO(4)+KH(2)PO(4); pH 3) (50:50, v/v-phase A) or (30:70, v/v-phase B) was validated by determination of the following parameters: selectivity, precision, linearity, stability of the analite and LOD as well as LOQ. Kinetic studies of the decomposition process of I in both acidic and alkaline environments indicate instability of the imide group. PMID:12818690

Muszalska, Izabela; Sadowska, Helena; Szkatula, Dominika

2003-07-01

234

Polyhydroxybenzoates inhibit ascorbic acid activation of mitochondrial glycerol-3-phosphate dehydrogenase: implications for glucose metabolism and insulin secretion.  

PubMed

Glycerol-3-phosphate dehydrogenase from pig brain mitochondria was stimulated 2.2-fold by the addition of 50 microm l-ascorbic acid. Enzyme activity, dependent upon the presence of l-ascorbic acid, was inhibited by lauryl gallate, propyl gallate, protocatechuic acid ethyl ester, and salicylhydroxamic acid. Homogeneous pig brain mitochondrial glycerol-3-phosphate dehydrogenase was activated by either 150 microm L-ascorbic acid (56%) or 300 microm iron (Fe(2+) or Fe(3+) (62%)) and 2.6-fold by the addition of both L-ascorbic acid and iron. The addition of L-ascorbic acid and iron resulted in a significant increase of k(cat) from 21.1 to 64.1 s(-1), without significantly increasing the K(m) of L-glycerol-3-phosphate (10.0-14.5 mm). The activation of pure glycerol-3-phosphate dehydrogenase by either L-ascorbic acid or iron or its combination could be totally inhibited by 200 microm propyl gallate. The metabolism of [5-(3)H]glucose and the glucose-stimulated insulin secretion from rat insulinoma cells, INS-1, were effectively inhibited by 500 microm or 1 mm propyl gallate and to a lesser extent by 5 mm aminooxyacetate, a potent malate-aspartate shuttle inhibitor. The combined data support the conclusion that l-ascorbic acid is a physiological activator of mitochondrial glycerol-3-phosphate dehydrogenase, that the enzyme is potently inhibited by agents that specifically inhibit certain classes of di-iron metalloenzymes, and that the enzyme is chiefly responsible for the proximal signal events in INS-1 cell glucose-stimulated insulin release. PMID:11060297

Wells, W W; Xu, D P; Washburn, M P; Cirrito, H K; Olson, L K

2001-01-26

235

Photoelectron spectroscopy of 1-propyl, 1-butyl, isobutyl, neopentyl, and 2-butyl radicals: free radical precursors to high-energy carbonium ion isomers. [Studied at elevated temperature to increase extent of radical decomposition  

SciTech Connect

The first photoelectron bands of 1-propyl, 1-butyl, isobutyl, neopentyl, and 2-butyl radicals have been obtained. Adiabatic and vertical ionization potentials, respectively, are 8.15 +/- 0.02 and 8.43 +/- 0.02 eV for 1-propyl radical, 8.02 (+0.04 - 0.1) and 8.50 +/- 0.04 ev for 1-butyl radical, 7.93 (+0.03-0.1) and 8.31 +/- 0.03 eV for isobutyl radical, 7.88 +/- 0.05 and 8.25 +/- 0.03 eV for neopentyl radical, and 7.25 +/- 0.02 and 7.59 +/- 0.03 eV for 2-butyl radical. From recently determined or estimated heats of formation of the radicals, heats of formation of the corresponding carbonium ions are calculated to be 210.5 +/- 1.1 kcal/mol for 1-propyl cation, 201.9 +/- 3 kcal/mol for 1-butyl cation, 197.9 +/- 3 kcal/mol for isobutyl cation, 188.8 +/- 2.3 kcal/mol for neopentyl cation, and 181.0 +/- 1.1 kcal/mol for 2-butyl cation. The energetics of ion solvation processes are assessed from a comparison of the gas-phase results to solution data where these ions are generated as nascent products of ionization processes or are proposed as reaction intermediates in isomerization reactions. With the exception of the 1-propyl radical spectrum, the spectra exhibit no resolved vibrational structure. The possible origins of a weakly resolved 540 +/- 160 cm/sup -1/ vibrational progression observed on the 1-propyl radical band are discussed. An analysis of these spectra, along with those of ethyl and 2-propyl radicals, reveals treads in ionization potentials that may be interpreted in terms of inductive and hyperconjugative effects of methyl substituents ..beta.. to primary or secondary cation centers. 96 references, 7 figures, 2 tables.

Schultz, J.C.; Houle, F.A.; Beauchamp, J.L.

1984-07-11

236

Peptides with juvenile hormone activity.  

PubMed

Peptide derivatives of juvenile hormone analogs which show substantial hormonal activity for certain insects were prepared. The most active compound, L-isoleucyl-L-alanyl-p-aminobenzoic acid ethyl ester, was up to twice as active as juvabione. Like juvabione, the peptide analog showed selective action on pyrrhocorid bugs. PMID:5452900

Zaoral, M; Sláma, K

1970-10-01

237

Peptides with Juvenile Hormone Activity  

Microsoft Academic Search

Peptide derivatives of juvenile hormone analogs which show substantial hormonal activity for certain insects were prepared. The most active compound, L-isoleucyl-L-alanyl-p-aminobenzoic acid ethyl ester, was up to twice as active as juvabione. Like juvabione, the peptide analog showed selective action on pyrrhocorid bugs.

M. Zaoral; K. Slama

1970-01-01

238

A new isolate of the rhodospirillum fulvum group and its photosynthetic pigments  

Microsoft Academic Search

The present paper reports the isolation of an obligate phototrophic bacterium which belongs to the Rhodospirillum fulvum-group on the basis of its colour, morphology, nutritional requirements and strictly anaerobic nature. p-Aminobenzoic acid was shown to be the only growth factor required.

N. Peennig; K. E. Eimhjellen; S. Liaaen Jensen

1965-01-01

239

Effect of yeast extract and vitamin B sub 12 on ethanol production from cellulose by Clostridium thermocellum I-1-B  

SciTech Connect

Addition to media of yeast extract, a vitamin mixture containing vitamin B{sub 12}, biotin, pyridoxamine, and p-aminobenzoic acid, or vitamin B{sub 12} alone enhanced formation of ethanol but decreased lactate production in the fermentation of cellulose by Clostridium thermocellum I-1-B. A similar effect was not observed with C. thermocellum ATCC 27405 and JW20.

Sato, Kanji; Goto, Shingo; Yonemura, Sotaro; Sekine, Kenji; Okuma, Emiko; Takagi, Yoshio; Honnami, Koyu; Saiki, Takashi (New Energy and Industrial Technology Development Organization, Chiba (Japan))

1992-02-01

240

An ultrasensitive photoelectrochemical nucleic acid biosensor  

PubMed Central

A simple and ultrasensitive procedure for non-labeling detection of nucleic acids is described in this study. It is based on the photoelectrochemical detection of target nucleic acids by forming a nucleic acid/photoreporter adduct layer on an ITO electrode. The target nucleic acids were hybridized with immobilized oligonucleotide capture probes on the ITO electrode. A subsequent binding of a photoreporter—a photoactive threading bis-intercalator consisting of two N,N?-bis(3-propyl-imidazole)-1,4,5,8-naphthalene diimides (PIND) linked by a Ru(bpy)22+ (bpy = 2,2?-bipyridine) complex (PIND–Ru–PIND)—allowed for photoelectrochemical detection of the target nucleic acids. The extremely low dissociation rate of the adduct and the highly reversible photoelectrochemical response under visible light illumination (490 nm) make it possible to conduct nucleic acid detection, with a sensitivity enhancement of four orders of magnitude over voltammetry. These results demonstrate for the first time the potential of photoelectrochemical biosensors for PCR-free ultrasensitive detection of nucleic acids.

Gao, Zhiqiang; Tansil, Natalia C.

2005-01-01

241

Molecular Engineering of Liquid Crystal Polymers by Living Polymerization. VIII. Influence of Molecular Weight on the Phase Behavior of Poly {?-[(4-Cyano-4?-biphenyl)-oxy]alkyl Vinyl Ether}s with Ethyl, Propyl, and Butyl Alkyl Groups  

Microsoft Academic Search

The synthesis and living cationic polymerization of 2-[4-cyano-4?-biphenyl)oxy]ethyl vinyl ether (6–2), 3-[4-cyano-4?-biphenyl)oxy]-propyl vinyl ether (6-3), and 4-[4-cyano-4?-biphenyl)oxy]butyl vinyl ether (6-4) are described. The mesomorphic behaviors of poly(6–2), poly(6-3), and poly(6-4) with different degrees of polymerization and narrow molecular weight distributions were compared to those of 6–2, 6–3, and 6–4 and of 2-[(4-cyano-4?-biphenyl)oxy]ethyl ethyl ether (8–2), 3-[(4-cyano-4?-biphenyl)oxy]propyl ethyl ether (8–3), and

Virgil Percec; Myongsoo Lee

1991-01-01

242

Bis(?-nitrato-?2 O:O)bis-{[1,2-bis-(diiso-propyl-phosphan-yl)-1,2-dicarba-closo-dodeca-borane-?2 P,P?]silver(I)} di-chloro-methane 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.

Yang, Liguo

2014-01-01

243

Identification of a potent antibacterial factor isolated from bronchoalveolar lavage fluid: guanidine, N-[3-[(aminoiminomethyl)amino]propyl]-N-dodecyl-, a potential source of error in the analysis of antibacterial agents.  

PubMed

The widespread use of antibiotics in modern society has encouraged the search for new antibacterial compounds. In this laboratory investigations are being made to identify and characterise novel antibacterial peptides. With this in mind, the antibacterial properties of human bronchoalveolar lavage (BAL) fluid from sarcoidosis patients is being investigated. In this communication we report on the identification and characterisation of a highly active non-peptide antibacterial compound isolated from BAL fluid. The structure of this active compound was elucidated by high-resolution accurate mass and tandem mass spectrometry to be guanidine, N-[3-[(aminoiminomethyl)amino]propyl]-N-dodecyl-. This compound does not appear to be endogenous, and its presence in BAL fluid extracts presents a potential source of error in analysis of antibacterial agents. The biological effects of guanidine, N-[3-[(aminoiminomethyl)amino]propyl]-N-dodecyl- have not previously been described in the literature. PMID:12539181

Abraham-Nordling, Mirna; Gudmundsson, Gudmundur H; Grunewald, Johan; Agerberth, Birgitta; Griffiths, William J

2003-01-01

244

A Chemogenomic Screening of Sulfanilamide-Hypersensitive Saccharomyces cerevisiae Mutants Uncovers ABZ2, the Gene Encoding a Fungal Aminodeoxychorismate Lyase?  

PubMed Central

Large-scale phenotypic analyses have proved to be useful strategies in providing functional clues about the uncharacterized yeast genes. We used here a chemogenomic profiling of yeast deletion collections to identify the core of cellular processes challenged by treatment with the p-aminobenzoate/folate antimetabolite sulfanilamide. In addition to sulfanilamide-hypersensitive mutants whose deleted genes can be categorized into a number of groups, including one-carbon related metabolism, vacuole biogenesis and vesicular transport, DNA metabolic and cell cycle processes, and lipid and amino acid metabolism, two uncharacterized open reading frames (YHI9 and YMR289w) were also identified. A detailed characterization of YMR289w revealed that this gene was required for growth in media lacking p-aminobenzoic or folic acid and encoded a 4-amino-4-deoxychorismate lyase, which is the last of the three enzymatic activities required for p-aminobenzoic acid biosynthesis. In light of these results, YMR289w was designated ABZ2, in accordance with the accepted nomenclature. ABZ2 was able to rescue the p-aminobenzoate auxotrophy of an Escherichia coli pabC mutant, thus demonstrating that ABZ2 and pabC are functional homologues. Phylogenetic analyses revealed that Abz2p is the founder member of a new group of fungal 4-amino-4-deoxychorismate lyases that have no significant homology to its bacterial or plant counterparts. Abz2p appeared to form homodimers and dimerization was indispensable for its catalytic activity.

Botet, Javier; Mateos, Laura; Revuelta, Jose L.; Santos, Maria A.

2007-01-01

245

Prophylactic and Therapeutic Benefits of Short-Term 9-[2-(R)-(Phosphonomethoxy)Propyl]Adenine (PMPA) Administration to Newborn Macaques following Oral Inoculation with Simian Immunodeficiency Virus with Reduced Susceptibility to PMPA  

Microsoft Academic Search

Simian immunodeficiency virus (SIV) infection of newborn macaques is a useful animal model of human pediatric AIDS to study pathogenesis and to develop intervention strategies aimed at preventing infection or delaying disease progression. In previous studies, we demonstrated that 9-(2-(R)-(phosphonomethoxy)propyl) adenine (PMPA; tenofovir) was highly effective in protecting newborn macaques against infection with virulent wild-type (i.e., drug-susceptible) SIVmac251. In the

KOEN K. A. VAN ROMPAY; MICHAEL D. MILLER; MARTA L. MARTHAS; NICOLAS A. MARGOT; PETER J. DAILEY; DON R. CANFIELD; ROSS P. TARARA; JULIE M. CHERRINGTON; NANCY L. AGUIRRE; NORBERT BISCHOFBERGER; NIELS C. PEDERSEN

2000-01-01

246

1-[3-(2-[ 18 F]Fluoropyridin-3-yloxy)propyl]pyrrole-2,5-dione:  Design, Synthesis, and Radiosynthesis of a New [ 18 F]Fluoropyridine-Based Maleimide Reagent for the Labeling of Peptides and Proteins  

Microsoft Academic Search

FPyME (1-(3-(2-fluoropyridin-3-yloxy)propyl)pyrrole-2,5-dione) was designed as a (18F)fluoropyridine- based maleimide reagent for the prosthetic labeling of peptides and proteins via selective conjugation with a thiol (sulfhydryl) function. Its pyridinyl moiety carries the radioactive halogen (fluorine-18) which can be efficiently incorporated via a nucleophilic heteroaromatic substitution, and its maleimido function ensures the efficient alkylation of a free thiol function as borne by

Béatrice de Bruin; Bertrand Kuhnast; Françoise Hinnen; Loïc Yaouancq; Mohamed Amessou; Ludger Johannes; Alain Samson; Raphaël Boisgard; Bertrand Tavitian; Frederic Dolle ´

2005-01-01

247

Mechanical and structural properties underlying contraction of skeletal muscle fibers after partial 1-ethyl-3-[3-dimethylamino)propyl]carbodiimide cross-linking.  

PubMed Central

We show prolonged contraction of permeabilized muscle fibers of the frog during which structural order, as judged from low-angle x-ray diffraction, was preserved by means of partial cross-linking of the fibers using the zero-length cross-linker 1-ethyl-3-[3-dimethylamino)propyl]carbodiimide. Ten to twenty percent of the myosin cross-bridges were cross-linked, allowing the remaining 80-90% to cycle and generate force. These fibers displayed a well-preserved sarcomeric order and mechanical characteristics similar to those of intact muscle fibers. The intensity of the brightest meridional reflection at 14.5 nm, resulting from the projection of cross-bridges evenly spaced along the myofilament length, decreased by 60% as a relaxed fiber was deprived of ATP and entered the rigor state. Upon activation of a rigorized fiber by the addition of ATP, the intensity of this reflection returned to 97% of the relaxed value, suggesting that the overall orientation of cross-bridges in the active muscle was more perpendicular to the filament axis than in rigor. Following a small-amplitude length step applied to the active fibers, the reflection intensity decreased for both releases and stretches. In rigor, however, a small stretch increased the amplitude of the reflection by 35%. These findings show the close link between cross-bridge orientation and tension changes. Images FIGURE 1 FIGURE 6

Bershitsky, S; Tsaturyan, A; Bershitskaya, O; Mashanov, G; Brown, P; Webb, M; Ferenczi, M A

1996-01-01

248

Radioiodinated N-[3-(4-morpholino)propyl]-N-methyl-2-hydroxy-5-iodo-3-methylbenzylamine (ERC9): a new potential melanoma imaging agent.  

PubMed

The role of nuclear medicine in the management of patients with malignant melanoma has expanded in recent years with the introduction of lymphoscintigraphy and sentinel lymph node biopsy, intense interest in positron emission tomography (PET) imaging using 2-[18F]fluoro-2-deoxyglucose (18F-FDG) as a tracer, and encouraging reports of several new single-photon-emitting radiopharmaceuticals. While PET imaging with FDG exhibits a high sensitivity for imaging patients with melanoma, specificity may not be as high and access to the technology remains limited. Single-photon emission tomography (SPET) imaging remains standard technology for most nuclear medicine departments. We report a novel radiopharmaceutical--radioiodinated N-[3-(4-morpholino)-propyl]-N-methyl-2-hydroxy-5-iodo-3-methylbenzylamine (ERC9)--which appears to show a sensitivity and specificity that are commensurate with expectations of a radiopharmaceutical for routine clinical imaging. In this phase II trial, 110 patients at risk for recurrence, with suspected recurrence or being restaged have been imaged with this novel tracer, demonstrating an overall sensitivity of 91% and specificity of 89%. The results of our study support a phase III trial to establish the clinical role of ERC9 in staging melanoma patients at presentation who are at high risk for metastasis, or restaging patients with known relapse to assess the extent of their disease, particularly if therapy or enrollment into a clinical trial is being considered. PMID:11357490

Salopek, T G; Scott, J R; Joshua, A V; Smylie, M; Logus, J W; Morin, C A; McEwan, A J

2001-04-01

249

Rate constants for the reaction of OH radicals with n-propyl, n-butyl, iso-butyl and tert-butyl vinyl ethers  

NASA Astrophysics Data System (ADS)

Rate constants for the reaction of OH radicals with n-propyl vinyl ether (PVE, CH 3CH 2CH 2OCH dbnd CH 2), n-butyl vinyl ether (BVE, CH 3CH 2CH 2CH 2OCH dbnd CH 2), iso-butyl vinyl ether (IBVE, (CH 3) 2CHCH 2OCH dbnd CH 2) and tert-butyl vinyl ether (TBVE, (CH 3) 3COCH dbnd CH 2), have been measured in the temperature and pressure ranges 232-373 K and 30-300 Torr using the pulsed laser photolysis-laser-induced fluorescence method, and at 298 K and 760 Torr using the relative method. The obtained results are k1=(9.3±0.6)×10 -12 exp[(708±20)/ T], k2=(1.5±0.2)×10 -11 exp[(572±42)/ T], k3=(1.6±0.1)×10 -11 exp[(567±20)/ T], k4=(1.7±0.2)×10 -11 exp[(549±25)/ T] cm 3 molecule -1 s -1. The values at 298 K are k1=(1.0±0.1)×10 -10, k2=(1.0±0.1)×10 -10, k3=(1.1±0.1)×10 -10, k4=(1.1±0.1)×10 -10 cm 3 molecule -1 s -1. The deduced tropospheric lifetimes of these ethers for reaction with OH are of the order of 1 h and they are comparable to those for reaction with ozone.

Thiault, G.; Mellouki, A.

250

Novel azido and isothiocyanato analogues of [3-(4-phenylalkylpiperazin-1-yl)propyl]bis(4-fluorophenyl)amines as potential irreversible ligands for the dopamine transporter.  

PubMed

Potential irreversible ligands were prepared, based on a series of 3-(1-piperazinyl)propyl-N,N-bis(4-fluorophenyl)amines, as molecular probes for the dopamine transporter (DAT). Both azido- and isothiocyanato-substituted phenylalkyl analogues were synthesized and evaluated for displacement of [(3)H]WIN 35 428 in rat caudate putamen tissue. All of the analogues showed moderate binding potencies at the DAT. The azido analogue, 16b, was radioiodinated and used to photolabel human DAT-transfected HEK 293 cell membranes. [(125)I]16b irreversibly labeled an approximately 80 kDa band corresponding to the DAT detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This radioligand provides a novel addition to the growing arsenal of structurally diverse irreversible ligands that are being used to identify binding domains on the DAT. Characterizing points of attachment of these irreversible probes to the DAT protein will ultimately help elucidate the three-dimensional arrangement of the transmembrane domains, identify individual binding sites of the DAT inhibitors, and direct future drug design. PMID:15566284

Cao, Jianjing; Lever, John R; Kopajtic, Theresa; Katz, Jonathan L; Pham, Anh T; Holmes, Muhsinah L; Justice, Joseph B; Newman, Amy Hauck

2004-12-01

251

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

252

Quantitative determination of butylated hydroxyanisole and n-propyl gallate in cosmetics using three-dimensional fluorescence coupled with second-order calibration.  

PubMed

This work presents a novel approach for simultaneous determination of butylated hydroxyanisole (BHA) and propyl gallate (PG) in a very interfering environment by combining the sensitivity of molecular fluorescence and the selectivity of the second-order calibration method. The excitation-emission fluorescence matrix data are processed by applying the second-order calibration method based on the self-weighted alternating normalized residue fitting (SWANRF) algorithm. The limits of detection (LOD) were 1.2-1.3 ng/ml for BHA and 2.2-2.9 ng/ml for PG. The recoveries from spiked cosmetics samples are in the ranges 95.7-103.9% for BHA and 95.9-105.7% for PG. The proposed method avoids preconcentration and elution procedures, so it considerably decreases the analytical time and the experimental expenses. Because the instrument involved in the measurement is nonsophisticated, the experiments could be carried out in routine laboratories. Then it is compared with the HPLC method in dosage of cosmetics and organic reagents, runtime, cost per analysis and LOD. PMID:24148414

Wang, Jian-Yao; Wu, Hai-Long; Chen, Yao; Zhai, Min; Qing, Xiang-Dong; Yu, Ru-Qin

2013-11-15

253

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

254

Pharmacokinetics in melanoma-bearing mice of 5-dihydroxyboryl-6-propyl-2-thiouracil (BPTU), a candidate compound for boron neutron capture therapy.  

PubMed

Blood pharmacokinetics and tissue distribution of 5-dihydroxyboryl-6-propyl-2-thiouracil (BPTU), a boron carrier with postulated melanin-seeking properties for boron neutron capture therapy, were determined in C57/BL mice with subcutaneous pigmented or non-pigmented B16 melanomas. Borocaptate sodium (BSH) was used as a boron compound without melanin-seeking properties in a comparative biodistribution study in the same animal tumour models. Administration of single doses showed that BPTU was retained better in the pigmented B16 tumour than in the non-pigmented variant. BPTU was found in large concentrations in kidney and liver. Brain boron was approximately 10-fold lower than tumour boron. On a molar basis, BPTU demonstrated higher affinity for B16 tumours than BSH. Owing to solubility limits, tumour boron concentrations in this mouse study were too low for effective application of BNCT. However, the high tumour-to-blood and tumour-to-normal tissues ratios indicate that, with appropriate formulation, BPTU could be a promising candidate for clinical BNCT. PMID:8142252

Verrijk, R; Smolders, I J; Huiskamp, R; Gavin, P R; Philipp, K H; Begg, A C

1994-04-01

255

Mercury speciation and analysis in drinking water by stir bar sorptive extraction with in situ propyl derivatization and thermal desorption-gas chromatography-mass spectrometry.  

PubMed

A method for mercury analysis and speciation in drinking water was developed, which involved stir bar sorptive extraction (SBSE) with in situ propyl derivatization and thermal desorption (TD)-GC-MS. Ten millilitre of tap water or bottled water was used. After a stir bar, pH adjustment agent and derivatization reagent were added, SBSE was performed. Then, the stir bar was subjected to TD-GC-MS. The detection limits were 0.01 ng mL(-1) (ethylmercury; EtHg), 0.02 ng mL(-1) (methylmercury; MeHg), and 0.2 ng mL(-1) (Hg(II) and diethylmercury (DiEtHg)). The method showed good linearity and correlation coefficients. The average recoveries of mercury species (n=5) in water samples spiked with 0.5, 2.0, and 6.0 ng mL(-1) mercury species were 93.1-131.1% (RSD<11.5%), 90.1-106.4% (RSD<7.8%), and 94.2-109.6% (RSD<8.8%), respectively. The method enables the precise determination of standards and can be applied to the determination of mercury species in water samples. PMID:18823893

Ito, Rie; Kawaguchi, Migaku; Sakui, Norihiro; Honda, Hidehiro; Okanouchi, Noriya; Saito, Koichi; Nakazawa, Hiroyuki

2008-10-31

256

Bridged amine-functionalized mesoporous organosilica materials from 1,2-bis(triethoxysilyl)ethane and bis[(3-trimethoxysilyl)propyl]amine  

NASA Astrophysics Data System (ADS)

Amine-functionalized, organic/inorganic hybrid mesostructured organosilica (BAFMO) materials have been synthesized and characterized from two bridged silsesquioxane precursors, 1,2-bis(triethoxysilyl)ethane (BTESE) and bis[(3-trimethoxysilyl)propyl]amine (BTMSPA). Mole ratios of BTESE ranged from 0.05, 0.10, 0.125, to 0.175. The synthetic pathway involves employing cetyltrimethylammonium bromide as a template under basic conditions at room temperature. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies revealed that the resultant BAFMO materials possess mesocopically ordered, hexagonal symmetries and well-defined morphologies. However, the order was decreased as the amount of BTMSPA increased, in terms of the d100 spacings and the unit cell parameters on XRD as well as the TEM images. N 2 gas sorption experiments showed a gradual decrease in both the surface area, from 1075 to 688 m 2/g, and the pore volume, from 2.08 to 0.55 cm 3/g, on increasing the amount of BTMSPA. The organic functionalization was successfully determined by Fourier-transform infrared and 13C CP MAS NMR spectroscopy. X-ray photoelectron spectroscopy and elemental analysis results also confirmed the presence of Si-C bond as well as amine functionalities in the solvent-extracted mesoporous organosilica materials.

Wahab, Mohammad A.; Kim, Il; Ha, Chang-Sik

2004-10-01

257

Extraction of U(VI), Th(IV), and La(III) from acidic streams and geological samples using AXAD-16–POPDE polymer  

Microsoft Academic Search

A new chromatographic extraction method has been developed using Amberlite XAD-16 (AXAD-16) resin chemically modified with (3-hydroxyphosphinoyl-2-oxo-propyl)phosphonic acid dibenzyl ester (POPDE). The chemically modified polymer was characterized by 13C CPMAS and 31P solid-state NMR, Fourier Transform–NIR–FIR–Raman spectroscopy, CHNPS elemental analysis, and thermogravimetric analysis. Extraction studies performed for U(VI), Th(IV), and La(III) showed good distribution ratio ( D) values of approximately

D. Prabhakaran; M. S. Subramanian

2004-01-01

258

Urinary Amino Acid Analysis: A Comparison of iTRAQ(R)-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.

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

2009-01-01

259

Furan fatty acids: occurrence, synthesis, and reactions. Are furan fatty acids responsible for the cardioprotective effects of a fish diet?  

PubMed

Furan FA (F-acids) are tri- or tetrasubstituted furan derivatives characterized by either a propyl or pentyl side chain in one of the alpha-positions; the other is substituted by a straight long-chain saturated acid with a carboxylic group at its end. F-acids are generated in large amounts in algae, but they are also produced by plants and microorganisms. Fish and other marine organisms as well as mammals consume F-acids in their food and incorporate them into phospholipids and cholesterol esters. F-acids are catabolized to dibasic urofuran acids, which are excreted in the urine. The biogenetic precursor of the most abundant F-acid, F6, is linoleic acid. Methyl groups in the beta-position are derived from adenosylmethionine. Owing to the different alkyl substituents, synthesis of F-acids requires multistep reactions. F-acids react readily with peroxyl radicals to generate dioxoenes. The radical-scavenging ability of F-acids may contribute to the protective properties of fish and fish oil diets against mortality from heart disease. PMID:16296395

Spiteller, Gerhard

2005-08-01

260

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

261

Enhanced porphyrin accumulation using dendritic derivatives of 5-aminolaevulinic acid for photodynamic therapy: an in vitro study.  

PubMed

Intracellular porphyrin generation following administration of 5-aminolaevulinic acid has been widely used in photodynamic therapy for a range of malignant and certain non-malignant lesions. However, cellular uptake of 5-aminolaevulinic acid is limited by its hydrophilic nature and improved means of delivery are therefore being sought. Highly branched polymeric drug carriers known as dendrimers are a promising new approach to drug delivery. The aim of this study was to investigate the efficacy of dendrimers conjugated with 5-aminolaevulinic acid for porphyrin production in the transformed PAM 212 keratinocyte cell line and skin explants. Each dendritic derivative incorporated three 5-aminolaevulinic acid residues which were conjugated as esters via methyl or propyl linkers to a central tertiary carbon whose remaining terminal bore an amino, aminobenzyloxycarbonyl or nitro group. In the cell line, all compounds were more efficient at low concentrations compared to equimolar 5-aminolaevulinic acid for porphyrin production, with the most efficient incorporating the longer propyl linker. This compound was also the most lipophilic according to partition coefficient measurements. The intracellular porphyrin fluorescence levels showed good correlation with cellular phototoxicity following light exposure for all the compounds, together with minimal dark toxicity. Our findings indicate that the key factors influencing the efficacy of the dendritic derivatives are lipophilicity and steric hindrance within the dendritic structure which could restrict access to intracellular esterases for liberation of 5-aminolaevulinic acid. These findings should be taken into account in the design of larger dendrimers of 5-aminolaevulinic acid. PMID:16546435

Battah, Sinan; O'Neill, Sophie; Edwards, Christine; Balaratnam, Sherina; Dobbin, Paul; MacRobert, Alexander J

2006-01-01

262

NMDA inhibits oxotremorine-induced acid secretion via the NO-dependent cyclic GMP system in rat stomach.  

PubMed

The mechanism of N-methyl-D-aspartate (NMDA) inhibits oxotremorine-induced acid secretion was examined in rat stomach, in relation to the cyclic GMP system. NMDA (10(-7) M) did not affect the spontaneous acid secretion from the everted preparations of isolated rat stomach, but inhibited the acid secretion stimulated by oxotremorine, and this effect of NMDA was antagonized by 2-amino-5-phosphonovaleric acid (AP-5), (+/-)3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) or N(G)-nitro-L-arginine (L-NNA). NMDA also elevated the cyclic GMP content of mucosal slices from rat stomach, and this effect of NMDA was antagonized by L-NNA. These results indicate that NMDA receptors are present in the rat stomach and regulate the gastric acid secretion. The mechanism underlying the effect of NMDA inhibits oxotremorine-induced acid secretion may be mediated by the NO-dependent cyclic GMP system. PMID:11908548

Tsai, L H; Lee, Y J

2001-12-31

263

Pharmacokinetics of the dopamine D2 agonist S(-)-2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin in freely moving rats.  

PubMed

The pharmacokinetics of the dopamine D2 agonist S(-)-2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin (1, N-0923) after intravenous, intraperitoneal, and oral administration was studied in freely moving male and female albino Wistar rats. In all cases, the dose was 10 mumol.kg-1. Levels of 1 in plasma were monitored up to 6 h after dosing by high-performance liquid chromatography. A biphasic disappearance pattern with a rapid distribution phase was observed in the curve of concentration in plasma versus time. Pharmacokinetic analysis based on a two-compartment model with elimination from the central compartment yielded the following parameters for male rats (mean +/- standard deviation, n = 3): elimination half-life was 108 +/- 7 min, apparent volume of distribution of the central compartment was 397 +/- 44 mL.kg-1, the plasma clearance was 32 +/- 4 mL.min-1.kg-1, and the apparent volume of distribution at steady state was 2.29 +/- 0.25 L.kg-1. No significant difference (analysis of variance p value > 0.25) was found in the pharmacokinetic data between male and female rats. An extremely fast absorption was found after intraperitoneal administration. Maximal concentrations in plasma were often observed at the first time point 5 min after dosing. The bioavailability (mean +/- standard deviation, n = 3) was 7.9 +/- 2.7% for male rats and 6.5 +/- 2.1% for female rats. An increase of the elimination half-life of at least 40% for male rats and 300% for female rats was observed, indicating dose-dependent kinetics after intraperitoneal administration.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8095299

Swart, P J; de Zeeuw, R A

1993-02-01

264

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

265

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

266

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

267

Efficient dendrimer-DNA complexation and gene delivery vector properties of nitrogen-core poly(propyl ether imine) dendrimer in mammalian cells.  

PubMed

Dendrimers as vectors for gene delivery were established, primarily by utilizing few prominent dendrimer types so far. We report herein studies of DNA complexation efficacies and gene delivery vector properties of a nitrogen-core poly(propyl ether imine) (PETIM) dendrimer, constituted with 22 tertiary amine internal branches and 24 primary amines at the periphery. The interaction of the dendrimer with pEGFPDNA was evaluated through UV-vis, circular dichroism (CD) spectral studies, ethidium bromide fluorescence emission quenching, thermal melting, and gel retardation assays, from which most changes to DNA structure during complexation was found to occur at a weight ratio of dendrimer:DNA ? 2:1. The zeta potential measurements further confirmed this stoichiometry at electroneutrality. The structure of a DNA oligomer upon dendrimer complexation was simulated through molecular modeling and the simulation showed that the dendrimer enfolded DNA oligomer along both major and minor grooves, without causing DNA deformation, in 1:1 and 2:1 dendrimer-to-DNA complexes. Atomic force microscopy (AFM) studies on dendrimer-pEGFP DNA complex showed an increase in the average z-height as a result of dendrimers decorating the DNA, without causing a distortion of the DNA structure. Cytotoxicity studies involving five different mammalian cell lines, using [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide] (MTT) assay, reveal the dendrimer toxicity profile (IC50) values of ?400-1000 ?g mL(-1), depending on the cell line tested. Quantitative estimation, using luciferase assay, showed that the gene transfection was at least 100 times higher when compared to poly(ethylene imine) branched polymer, having similar number of cationic sites as the dendrimer. The present study establishes the physicochemical behavior of new nitrogen-core PETIM dendrimer-DNA complexes, their lower toxicities, and efficient gene delivery vector properties. PMID:23909622

Lakshminarayanan, Abirami; Ravi, Vijay Kumar; Tatineni, Ranjitha; Rajesh, Y B R D; Maingi, Vishal; Vasu, K S; Madhusudhan, Nandhitha; Maiti, Prabal K; Sood, A K; Das, Saumitra; Jayaraman, N

2013-09-18

268

4-Amino-1-(3-mercapto-propyl)-pyridine hexafluorophosphate ionic liquid functionalized gold nanoparticles for IgG immunosensing enhancement.  

PubMed

A novel ionic liquid, 4-amino-1-(3-mercapto-propyl)-pyridine hexafluorophosphate (AMPPH), was successfully synthesized and characterized. Subsequently, AMPPH was used as a functional monomer to fabricate AMPPH-modified gold nanoparticles (AMPPH-AuNPs) via a one-pot synthesis method. The as-prepared AMPPH-AuNPs were confirmed with transmission electron microscopy and X-ray photoelectron spectroscopy. AMPPH-AuNPs were used to construct a biocompatible interface to immobilize rabbit anti-human IgG (anti-HIgG) onto a glassy carbon electrode (GCE) surface, followed by a cross-linking step with glutaraldehyde to fabricate an anti-HIgG-AMPPH-AuNPs/GCE. The nonspecific binding sites were enclosed with bovine serum albumin (BSA) to develop an immunosensor for human IgG. Electrochemical impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical properties of the developed immunosensor. The results indicate that AMPPH-AuNPs can improve the immunosensing performance. The current response of the immunosensor was found linearly related to human IgG concentration in the range of 0.1-5.0 ng mL(-1) and 5.0-100.0 ng mL(-1). The detection limit is estimated to be 0.08 ng mL(-1) (S/N = 3). The obtained immunosensor was successfully applied to the analysis human IgG immunoglobulin in human serum, and the results were well consistent with ELISA method. PMID:24803006

Li, Rui; Wu, Kangbing; Liu, Changxian; Huang, Yin; Wang, Yanying; Fang, Huaifang; Zhang, Huijuan; Li, Chunya

2014-06-01

269

Carbodithioic acid esters of fluoxetine, a novel class of dual-function spermicides.  

PubMed

Carbodithioic acid esters of fluoxetine have been prepared by replacing the methylamino function in aminopropane chain with carbodithioic acid ester group and by adding various S-2-hydroxypropyl ester of dialkyl carbodithioic acid at 3-methylamino group. Some of these compounds showed spermicidal, antifungal and anti-Trichomonas activities. The study revealed that incorporation of carbodithioic acid residue directly into fluoxetine structure leads to compounds with better antifungal and anti-Trichomonas activities, and N-methyl-[3-phenyl-3-(4-trifluoromethyl-phenoxy)-propyl]carbodithioic acid S-(2-pyrrolidino-ethyl) ester (14) has shown better profile than both fluoxetine and nonoxynol-9. Further lead optimization may yield a potent dual-function spermicide. PMID:18061311

Kiran Kumar, S T V S; Kumar, Lalit; Sharma, Vishnu L; Jain, Ashish; Jain, Rajeev K; Maikhuri, Jagdamba P; Kumar, Manish; Shukla, Praveen K; Gupta, Gopal

2008-10-01

270

The interaction between sodium dodecylsulfate and the cationic-nonionic random copolymer (3-(2-methylpropionamide)propyl) trimethylammonium chloride–acrylamide of two different charge densities studied using dynamic light scattering and rheometry  

Microsoft Academic Search

The effects of complex formation between sodium dodecylsulfate (SDS) and the positively charged (3-(2-methylpropionamide)propyl)trimethyl-ammonium\\u000a chloride-acrylamide (MAPTAC-AM) copolymer have been studied in dilute and semidilute aqueous solution in the presence of 10?mM\\u000a NaCl. Two different charge densities of the copolymer have been used in the study: 0.31 and 0.66, corresponding to the proportion\\u000a of MAPTAC units. Dynamic light scattering (DLS) and

J. Fundin; W. Brown; I. Iliopoulos; P. M. Claesson

1999-01-01

271

Catalytic activity of Mn(III) and Fe(III) complexes of meso-tetra( n-propyl)porphyrin in oxidation of olefins: Meso-alkyl substituent in comparison with the alkenyl and aryl ones  

Microsoft Academic Search

Catalytic activity of Mn(III) and Fe(III) complexes of meso-tetra(n-propyl)porphyrin, MnT(n-Pr)P(X) and FeT(n-Pr)P(X) (X=Cl, SCN, OAc) in oxidation of olefins with tetra-n-butylammonium periodate at room temperature has been studied. The influence of different parameters including the molar ratio of catalyst to imidazole, type of counter ion (X) and oxidative stability of metalloporphyrins on the efficiency of the catalysts was investigated. The

Saeed Zakavi; Sadegh Talebzadeh; Saeed Rayati

272

Antischistosomal Activity of Hexadecyloxypropyl Cyclic 9-(S)-[3-Hydroxy-2-(Phosphonomethoxy)Propyl]Adenine and Other Alkoxyalkyl Esters of Acyclic Nucleoside Phosphonates Assessed by Schistosome Worm Killing In Vitro?  

PubMed Central

9-(S)-[3-Hydroxy-2-(phosphonomethoxy)propyl]adenine [(S)-HPMPA] has been reported to have antischistosomal activity. Ether lipid esters of (S)-HPMPA and cidofovir (CDV) have greatly increased activities in antiviral assays and in lethal animal models of poxvirus diseases. To see if ether lipid esters of CDV and (S)-HPMPA enhance antischistosomal activity, we tested their alkoxyalkyl esters using Schistosoma mansoni worm killing in vitro. Hexadecyloxypropyl (HDP)-cyclic-(S)-HPMPA and HDP-cyclic-CDV exhibited significant in vitro antischistosomal activities and may offer promise alone or in combination with praziquantel.

Botros, Sanaa S.; William, Samia; Beadle, James R.; Valiaeva, Nadejda; Hostetler, Karl Y.

2009-01-01

273

Analyzing poly(3-hexyl-thiophene):1-(3-methoxy-carbonyl)propyl-1-phenyl-(6,6)C61 bulk-heterojunction solar cells by UV-visible spectroscopy and optical simulations  

Microsoft Academic Search

A nondestructive method for assessing the thickness of the photoactive layer in poly(3-hexyl-thiophene):1-(3-methoxy-carbonyl)propyl-1-phenyl-(6,6)C61 (P3HT:PCBM) solar cells is reported. In the approach the absorption spectrum of the solar cell as derived by optical simulations is fitted to the corresponding measured spectrum, varying only the P3HT:PCBM layer thickness. Within the 50-250 nm thickness range, a linear correlation between the position of a

Kristian O. Sylvester-Hvid; Tobias Ziegler; Moritz K. Riede; Nicholas Keegan; Michael Niggemann; Andreas Gombert

2007-01-01

274

Structure-activity considerations and in vitro approaches to assess the genotoxicity of 19 methane-, benzene- and toluenesulfonic acid esters.  

PubMed

Sulfonic acid esters are considered as potentially alkylating agents that may exert genotoxic effects in bacterial and mammalian cell systems. One possible source of human exposure stems from drug synthesis when the salt-forming agents methanesulfonic acid, benzenesulfonic acid or p-toluenesulfonic acid are used together with alcoholic solvents such as methanol, ethanol and propanol. In this study computer-assisted structural considerations and in vitro approaches (Ames mutagenicity test using Salmonella typhimurium strains TA98 and TA100, and the micronucleus test using L5178Y mouse lymphoma cells) were used to assess the genotoxic properties of 19 sulfonic esters. While all esters may be principally active as genotoxicants based on the presence of the sulfonate moiety, the statistical correlative multiple computer automated structure evaluation (MCASE) system (MC4PC version 1.0) using the Ames mutagenicity A2I module (version 1.54), rank-ordered the activity of the benzenesulfonic acid esters in the Ames test negligible due to an inactivating modulator and a deactivating fragment, whereas the methane- and toluenesulfonic acid esters were predicted to be positive in this test. In the Ames test, with the exception of the p-toluenesulfonic acid ethyl and iso-butyl esters, all compounds came out positive in Salmonella strain TA100. Methanesulfonic iso-propyl, sec-butyl and benzenesulfonic acid iso-propyl ester also showed mutagenic potential in strain TA98. In general, differences between results seen in Ames tests performed with or without metabolic activation were rather small. In L5178Y mouse lymphoma cells, benzenesulfonic acid n- and iso-butyl ester and p-toluenesulfonic acid iso-butyl ester did not increase the number of cells containing micronuclei. The other esters were positive in this micronucleus test; however, methanesulfonic acid iso-butyl ester was found to be only weakly positive at excessively cytotoxic concentrations. These compounds were generally found to be more potent with regard to micronucleus induction when tested without metabolic activation (20 h treatment). In conclusion, the iso-propyl esters of the three sulfonic acids under study were found to be the strongest mutagens, either when tested in the Ames test or the micronucleus assay, whereas p-toluenesulfonic acid iso-butyl ester was the only compound shown to be devoid of a genotoxic potential in both tests. PMID:15725602

Glowienke, Susanne; Frieauff, Wilfried; Allmendinger, Thomas; Martus, Hans-Joerg; Suter, Willi; Mueller, Lutz

2005-03-01

275

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.  

PubMed

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 OH?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. PMID:24892527

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

2014-11-11

276

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

277

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 ...

278

Immobilized hyaluronic acid containing model silicone hydrogels reduce protein adsorption.  

PubMed

The physical immobilization of hyaluronic acid (HA) as a wetting agent in contact lens applications was investigated using model silicone hydrogels prepared by co-polymerizing methacryloxy propyl tris (trimethylsiloxy) silane (Tris) and hydroxyethylmethacrylate (HEMA). Two different molecular weights of HA were investigated, as well as various Tris/HEMA ratios. Cross-linked HA, while only present in small amounts, increased water uptake and hydrophilicity in the materials containing 10% Tris; however, no changes were observed in the 4% Tris materials. The presence of the HA was further confirmed by increases in glass transition temperature as measured by differential scanning calorimetry. Lysozyme adsorption was dramatically decreased for materials containing cross-linked HA. The incorporation of HA, previously demonstrated to decrease protein adsorption to model conventional hydrogel materials, may have significant potential for improving the wetting and other properties of silicone hydrogel contact lens materials. PMID:18973721

van Beek, Mark; Weeks, Andrea; Jones, Lyndon; Sheardown, Heather

2008-01-01

279

Rapid determination of four short-chain alkyl mercapturic acids in human urine by column-switching liquid chromatography-tandem mass spectrometry.  

PubMed

We developed and validated an analytical method for the simultaneous determination of methyl mercapturic acid (MeMA), ethyl mercapturic acid (EtMA), n-propyl mercapturic acid (PrMA) and iso-propyl mercapturic acid (iPrMA) in human urine. These alkyl mercapturic acids are known or presumed biomarkers of exposure to several alkylating agents including methyl bromide, dimethyl sulfate, ethyl bromide, 1-bromopropane and 2-bromopropane. The method involves a column switching arrangement for online solid phase extraction of the analytes with subsequent analytical separation and detection using liquid chromatography and tandem mass spectrometry. Within day and day-to-day imprecision was determined to range from 4.5 to 12.2%. The analytical method is distinguished by its wide linear working range of up to 2500?g/L with detection limits ranging from 2.0?g/L (for PrMA) to 5.1?g/L (for MeMA) that render possible the application in various biomonitoring studies regarding exposure to alkylating agents. The results of a pilot study on urine samples of 30 individuals occupationally non-exposed to alkylating agents using the new procedure confirmed the background excretion of MeMA (<5.1-35.6?g/L) and PrMA (<2.0-95.7?g/L). PMID:24997437

Eckert, Elisabeth; Göen, Thomas

2014-08-15

280

Nutritional Requirements of Selenomonas ruminantium for Growth on Lactate, Glycerol, or Glucose  

PubMed Central

The nutritional requirements of Selenomonas ruminantium HD4 for growth on glucose, glycerol, or lactate were investigated to clarify the results of previous studies and to relate the nutrition of the organism to its physiology. The organism required l-aspartate, CO2, p-aminobenzoic acid, and biotin for growth on a lactate-salts medium that contained small amounts of dithiothreitol. Aspartate could be replaced by l-malate or fumarate but not by succinate or l-asparagine. Requirements for growth with glycerol as an energy source were similar, except that aspartate was not required. With glucose as the energy source, neither aspartate nor p-aminobenzoic acid was required, but a requirement for volatile fatty acids, which could be met by n-valerate, was observed. CO2 was required for growth on lactate or glycerol but not on glucose on complex media containing Trypticase and yeast extract. Sulfide could be used as the sole source of sulfur.

Linehan, B.; Scheifinger, C. C.; Wolin, M. J.

1978-01-01

281

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.

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

2014-01-01

282

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

283

Design and synthesis of novel 3-(4-chlorophenyl)-2-(3-substituted propyl thio) quinazolin-4-(3H)-ones as a new class of H1-antihistaminic agents.  

PubMed

A series of novel 3-(4-chlorophenyl)-2-(3-substituted propyl) quinazolin-4-(3H)-ones have been synthesized and tested for their in vivo H1-antihistaminic activity on conscious guinea pigs. All the test compounds have protected the animals from histamine induced bronchospasm significantly. Compound 3-(4-chlorophenyl)-2-(3-(4-methylpiperazin-1-yl) propylthio) quinazolin-4(3H)-one (PC5) emerged as the most active compound (77.53% protection) of the series when compared to the reference standard chlorpheniramine maleate (70.09% protection). Compound PC5 shows negligible sedation (6.16%) compared to chlorpheniramine maleate (29.58%). Therefore, compound PC5 can serve as the lead molecule for further development into a new class of H1-antihistaminic agents. PMID:22855299

Alagarsamy, V; Parthiban, P

2012-09-01

284

Weakly Antiferromagentic Coupling Via Superexchange Interaction Between Mn(II)-Mn(II) Atoms: A QM/MM Study of the Active Site of Human Cytosolic X-Propyl Aminopeptidase P  

PubMed Central

We investigate the dinuclear manganese, Mn(II)-Mn(II), active site of human cytosolic X-propyl aminopeptidase (XPNPEP1) employing the QM/MM method. The optimized structure supports two manganese atoms at the active site and excludes the possibility of a single Mn(II) atom or other combination of divalent metal ions: Ca(II), Fe(II), Mg(II). A broken symmetry solution verifies an antiferromagnetically coupled state between the Mn(II)-Mn(II) pair, which is the ground state. From the energy difference between the high spin state (HS) and the broken symmetry state (BS), we estimate the exchange coupling constant, J, to be 5.15 cm-1. Also, we observe multiple bridges (p orbitals) from solvent and two carboxylate linking to the Mn(II)-Mn(II), which leads to the weakly antiferromagnetic interaction of d5-d5 electrons through superexchange coupling.

Wu, Sangwook; Sim, Sooyeon

2012-01-01

285

Effect of the Ruffled Porphyrin Ring on Electronic Structures: Structure and Characterization of [Fe(TalkylP)(OClO3)] and [Fe(TPrP)(THF)2]ClO4 (alkyl = Ethyl, Et and n-Propyl, Pr)  

PubMed Central

We report the synthesis of Fe(TalkylP)(OClO3)] (alkyl = ethyl and propyl) and [Fe(TPrP)(THF)2]ClO4, which are characterized by UV-vis, EPR, X-ray crystallography, and solid-state magnetic susceptibilities. The macrocycles of all three complexes are ruffled, all of the structural features for [Fe(TEtP(OClO3)] and [Fe(TPrP)(OClO3)] are characteristic of the nearly pure S = 3/2 state, while the structural parameters for [Fe(TPrP)(THF)2]ClO4 feature a pure intermediate-spin (S = 3/2) state, which are all consistent with EPR and magnetic data. It is clear from these studies that the ruffled conformation plays a significant role in affecting the extent of S = 3/2 character.

Li, Ming; Oliver, Allen G.; Neal, Teresa J.

2013-01-01

286

Tritium-labeled N(1)-[3-(1H-imidazol-4-yl)propyl]-N(2)-propionylguanidine ([(3)H]UR-PI294), a high-affinity histamine H(3) and H(4) receptor radioligand.  

PubMed

This study reports the synthesis and pharmacological characterization of tritium-labeled N(1)-[3-(1H-imidazol-4-yl)propyl]-N(2)-propionylguanidine ([(3)H]UR-PI294), a novel and readily accessible radioligand for the human histamine H(3) receptor (hH(3)R) and H(4) receptor (hH(4)R). The radioligand displays high affinity for both histamine receptor subtypes (K(D) (hH(3)R)=1.1 nM, K(D) (hH(4)R)=5.1 nM) and is shown to be a valuable pharmacological tool for the determination of hH(3)R and hH(4)R affinities. PMID:19101971

Igel, Patrick; Schnell, David; Bernhardt, Günther; Seifert, Roland; Buschauer, Armin

2009-02-01

287

Tetra-kis(di-propyl-ammonium) tetra-kis(oxa-lato-?2 O 1,O 2)stannate(IV) mono-hydrate: a complex with an eight-coordinate SnIV atom  

PubMed Central

In the title salt, [(CH3CH2CH2)2NH2]4[Sn(C2O4)4]·H2O, the SnIV atom of the stannate anion is located on a special position with -42m symmetry. It is eight-coordinated by four chelating oxalate anions. The di­propyl­ammonium cation possesses mirror symmetry while the lattice water mol­ecule is disordered about a position with -42m symmetry and has an occupancy of 0.25. In the crystal, the anions and cations are linked by N—H?O hydrogen bonds, forming a three-dimensional network. This network is futher stabilized by weak O—H?O hydrogen bonds involving the water mol­ecules and oxalate O atoms. The crystal studied was refined as an inversion twin.

Gueye, Ndongo; Diop, Libasse; Stoeckli-Evans, Helen

2014-01-01

288

Interaction of CPa-1 with the manganese-stabilizing protein of photosystem II: identification of domains cross-linked by 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide.  

PubMed

The structural organization of photosystem II proteins has been investigated by use of the zero-length protein cross-linking reagent 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide and monoclonal and polyclonal antibody reagents. Photosystem II membranes were treated with 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide which cross-links amino groups to carboxyl groups which are in van der Waals contact. This treatment did not affect the oxygen evolution rates of these membranes and increased the retention of oxygen evolution after CaCl2 washing. Analysis of the proteins cross-linked by this treatment indicated that two cross-linked species with apparent molecular masses of 95 and 110 kDa were formed which cross-reacted with antibodies against both the 33-kDa manganese-stabilizing protein and the chlorophyll protein CPa-1. Cleavage of the 110-kDa cross-linked species with cyanogen bromide followed by N-terminal sequence analysis was used to identify the peptide fragments of CPa-1 and the manganese-stabilizing protein which were cross-linked. Two cyanogen bromide fragments were identified with apparent molecular masses of 50 and 25 kDa. N-Terminal sequence analysis of the 50-kDa cyanogen bromide fragment indicates that this consists of the C-terminal 16.7-kDa fragment of CPa-1 and the intact manganese-stabilizing protein. This strongly suggests that the manganese-stabilizing protein is cross-linked to the large extrinsic loop domain of CPa-1. N-Terminal analysis of the 25-kDa cyanogen bromide fragment indicates that this consists of the C-terminal 16.7-kDa peptide of CPa-1 and the N-terminal 8-kDa peptide of the manganese-stabilizing protein.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1610808

Odom, W R; Bricker, T M

1992-06-23

289

Growth of Pseudomonas C on C1 Compounds: Continuous Culture  

PubMed Central

Pseudomonas C was grown in continuous culture on methanol, formaldehyde, or formate as sole carbon source. On methanol ?max = 0.49/h and yield constant (Y) = 0.54; on formaldehyde and on unsupplemented media, ?max was about 0.2/h and Y was 0.15, whereas addition of p-aminobenzoic acid, folic acid, serine, or glycine to the medium raised Y to about 0.26 to 0.29, and addition of p-aminobenzoic acid, folic acid, serine, nicotinamide adenine dinucleotide, and Tween 80 raised the yield to 0.35. On formate and on unsupplemented media, ?max = 0.2/h and Y = 0.02, whereas addition of 0.1 mM p-aminobenzoic acid increased ?max to about 0.47 and Y to about 0.23. At low cell concentrations or growth rates a beneficial effect of CO2 was observed. Formaldehyde or formate, when added together with methanol, were utilized simultaneously with the methanol.

Battat, E.; Goldberg, I.; Mateles, R. I.

1974-01-01

290

40 CFR 721.9582 - Certain perfluoroalkyl sulfonates.  

Code of Federal Regulations, 2010 CFR

...8-heptadecafluoro-N-[3-(trimethoxysilyl)propyl]- 67969-69-1 ...2-Propenoic acid, 2-methyl-, 3-(trimethoxysilyl)propyl ester, polymers with acrylic...7-pentadecafluoro-N-[3-(trimethoxysilyl)propyl]- 68259-06-3...

2010-07-01

291

40 CFR 721.9582 - Certain perfluoroalkyl sulfonates.  

Code of Federal Regulations, 2010 CFR

...8-heptadecafluoro-N-[3-(trimethoxysilyl)propyl]- 67969-69-1 ...2-Propenoic acid, 2-methyl-, 3-(trimethoxysilyl)propyl ester, polymers with acrylic...7-pentadecafluoro-N-[3-(trimethoxysilyl)propyl]- 68259-06-3...

2009-07-01

292

40 CFR 721.9582 - Certain perfluoroalkyl sulfonates.  

Code of Federal Regulations, 2013 CFR

...8-heptadecafluoro-N-[3-(trimethoxysilyl)propyl]- 67969-69-1 ...2-Propenoic acid, 2-methyl-, 3-(trimethoxysilyl)propyl ester, polymers with acrylic...7-pentadecafluoro-N-[3-(trimethoxysilyl)propyl]- 68259-06-3...

2013-07-01

293

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 ...

294

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 ...

295

1-(N-acylamino)alkyl sulfones from N-acyl-?-amino acids or N-alkylamides.  

PubMed

A variety of N-(1-methoxyalkyl)amides or carbamates react readily with sodium aryl sulfinates in the presence of triphenylphosphonium tetrafluoroborate or bromide in CHCl3 under mild conditions to give 1-(N-acylamino)alkyl sulfones in good yields. A combination of this reaction with the recently described electrochemical decarboxylative ?-methoxylation of N-acyl-?-amino acids to give N-(1-methoxyalkyl)amides in the presence of 3-(1-piperidino)propyl-functionalized silica gel (SiO2-Pip) enables an effective two-pot transformation of N-acyl-?-amino acids to 1-(N-acylamino)alkyl sulfones. Alternatively, N-(1-methoxyalkyl)amides can be obtained by electrochemical ?-methoxylation of either N-alkylamides, lactams, or N-alkylcarbamates. PMID:24575944

Adamek, Jakub; Mazurkiewicz, Roman; Pa?dzierniok-Holewa, Agnieszka; Grymel, Miros?awa; Ku?nik, Anna; Zieli?ska, Katarzyna

2014-03-21

296

New pleconaril and [(biphenyloxy)propyl]isoxazole derivatives with substitutions in the central ring exhibit antiviral activity against pleconaril-resistant coxsackievirus B3  

Microsoft Academic Search

Amino acid 1092 (AA1092) in capsid protein 1 of coxsackievirus B3 (CVB3) is located in close vicinity to the central phenoxy group of capsid binders (i.e. pleconaril). Whereas isoleucine is associated with drug susceptibility, leucine and methionine confer resistance to pleconaril. In the present study, novel analogues with different substitutions in the central phenoxy group were synthesized to study their

Michaela Schmidtke; Peter Wutzler; Romy Zieger; Olga B. Riabova; Vadim A. Makarov

2009-01-01

297

Simultaneous determination of trace levels of ethylmercury and methylmercury in biological samples and vaccines using sodium tetra( n -propyl)borate as derivatizing agent  

Microsoft Academic Search

Because of increasing awareness of the potential neurotoxicity of even low levels of organomercury compounds, analytical techniques\\u000a are required for determination of low concentrations of ethylmercury (EtHg) and methylmercury (MeHg) in biological samples.\\u000a An accurate and sensitive method has been developed for simultaneous determination of methylmercury and ethylmercury in vaccines\\u000a and biological samples. MeHg and EtHg were isolated by acid

Darija Gibi?ar; Martina Logar; Nuša Horvat; Andreja Marn-Pernat; Rafael Ponikvar; Milena Horvat

2007-01-01

298

[Conformations and interatomic distances in polymorphs of sulfanilamide].  

PubMed

By CNDO (Complete Neglect of Differential Overlap) molecular orbital method, interatomic distances and XYZ cartesian corrdinates were calculated in five polymorphs (monohydrated, alpha, two beta, and gamma) of sulfanilamide. Interatomic distances thus obtained are very close to those originally presented by Bells & Roblin and support the mechanism of action postulated long algo for sulfa drugs as being competitive antagonism with p-aminobenzoic acid. PMID:1088542

Korolkovas, A

1976-01-01

299

Specificity of the BT-PABA test for the diagnosis of exocrine pancreatic insufficiency in the dog  

Microsoft Academic Search

Exocrine pancreatic insufficiency in the dog has been assessed by the oral administration of the synthetic peptide N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-PABA), a specific substrate for pancreatic chymotrypsin. The subsequent assay of PABA in either the plasma or the urine clearly differentiated control animals from those with exocrine pancreatic insufficiency (EPI), the results being unaffected by combination of this pancreatic function with

RM Batt; LC Mann

1981-01-01

300

Salt intake in young Swedish men  

Microsoft Academic Search

Objective: To measure dietary salt intake in a Swedish population. Design: A cross-sectional study with measured 24 h urinary excretion of Na and K. Completeness of urine collection was assessed using p-aminobenzoic acid. The subjects were interviewed on their habitual food intake. Setting: Sahlgrenska University Hospital, Gothenburg, Sweden. Subjects: Eighty-six young men (age 18-20 years), randomly selected from the population

L Hulthén; M Aurell; S Klingberg; E Hallenberg; M Lorentzon; C Ohlsson

2010-01-01

301

Kinetics of acetyl CoA: Arylamine N?acetyltransferase from rapid and slow acetylator shrimp livers  

Microsoft Academic Search

N?acetyltransferase (NAT) activity was determined in 200 shrimps (Penaeus chinensis) livers using 2?aminofluorene (AF) and p?aminobenzoic acid (PABA) as substrates. Overall, the liver NAT activity of the 100 females was higher than the liver NAT activity of the 100 males. The activities (mean ± S.D.) of NAT from liver of males was 1.27 ± 0.52 nmol\\/min\\/mg protein for the acetylation

Jing G. Chung; Jau H. Lee; Heng C. Ho; Chin C. Ho; Jem M. Lai; Shih H. Chang; Chi F. Hung

1999-01-01

302

Measurement of furancarboxylic acid, a candidate for uremic toxin, in human serum, hair, and sweat, and analysis of pharmacological actions in vitro  

Microsoft Academic Search

3-Carboxy-4-methyl-5-propyl-2-furanpropionic acid (CMPF), a candidate for uremic toxin, was measured in human hair for examining\\u000a a possible utility as indicator of renal dysfunction. The serum concentration of CMPF was much higher (32.3?±?2.7??g\\/ml, n=17; mean?±?SEM) in uremic patients aged 40–55?years receiving hemodialysis treatment than in healthy younger subjects (3.61?±?0.19??g\\/ml,\\u000a n=22), aged 18–23 years. However, the hair concentration of CMPF tended to

Toshi Sassa; Hiroyuki Matsuno; Masayuki Niwa; Osamu Kozawa; Naohito Takeda; Toshimitu Niwa; Takashi Kumada; Toshihiko Uematsu

2000-01-01

303

Antinociceptive esters of N-methylanthranilic acid: Mechanism of action in heat-mediated pain.  

PubMed

Recently, we identified a new natural antinociceptive alkaloid ternanthranin, isopropyl N-methylanthranilate (ISOAN), from the plant species Choisya ternata Kunth (Rutaceae). In this work we concentrated on the elucidation of its mechanism of action in comparison with two other esters of this acid (methyl (MAN) and propyl (PAN)). Mice orally pre-treated with ISOAN, MAN or PAN (at 0.3, 1 and 3mg/kg) were less sensitive to chemical or thermal stimuli in different nociception models (formalin-, capsaicin- and glutamate-induced licking response, tail flick and hot plate). All compounds (1 and 3mg/kg) showed significant activity in the peripheral nociception models, as well as a dose-dependent spinal antinociceptive effect in the tail flick model. We observed that glibenclamide was able to reverse the antinociceptive effect of ISOAN in the hot plate model suggesting the involvement of K(+)ATP channels. The antinociceptive effect of MAN and PAN may be related to adrenergic, nitrergic and serotoninergic pathways. In addition, the antinociception of PAN was reverted by naloxone implying that the opioid pathway participates in its activity. The cholinergic and cannabinoid systems were found not be involved in the onset of the antinociceptive effects of any of the esters. In conclusion, isopropyl, methyl and propyl N-methylanthranilates produced significant peripheral and central antinociception at doses lower than that of morphine, the classical opioid analgesic drug, without causing toxicity. PMID:24486396

Pinheiro, Mariana Martins Gomes; Radulovi?, Niko S; Miltojevi?, Ana B; Boylan, Fabio; Dias Fernandes, Patrícia

2014-03-15

304

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

305

Acid rain  

Microsoft Academic Search

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

1979-01-01

306

Extraction of palladium(II) with 1-{[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1 H -1,2,4-triazole from nitrate-nitrite solutions modeling the composition of raffinates formed in the PUREX process  

Microsoft Academic Search

Extraction of palladium(II) with 1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1H-1,2,4-triazole in toluene from nitrate-nitrite solutions modeling in a number of components the composition of raffinates\\u000a formed in the PUREX process was studied. Conditions of a tenfold concentration of palladium(II) into an ammonia extract were\\u000a found.

G. R. Anpilogova; R. A. Khisamutdinov; Yu. I. Murinov

2010-01-01

307

Synthesis, anticonvulsant properties and 5-HT1A/5-HT2A receptor affinity of new N-[(4-arylpiperazin-1-yl)-propyl]-2-aza-spiro[4.4]nonane and [4.5]decane-1,3-dione derivatives.  

PubMed

A series of twenty new N-[(4-arylpiperazin-1-yl)-propyl]-2-aza-spiro[4.4]nonane- and [4.5]decane-1,3-dione derivatives were synthesized and their anticonvulsant activity was evaluated in maximal electroshock (MES) and sc pentertazole (sc PTZ) tests. Their neurotoxicity was examined as well. Although no antiseizure properties of the investigated compounds were found in the MES model, eight of them were active in the sc PTZ test and three, namely 2-{3-[4-(2-fluorophenyl)-piperazin-1yl]-propyl}-2-aza-spiro[4.4]nonane-1,3-dione (7), 2-{3-[4-(2-fluorophenyl)-piperazin-1-yl]-propyl}-7-methyl-2-aza-spiro[4.5]-decane-1,3- dione (22) and 2-{3-[4-(3-chlorophenyl)-piperazin-1-yl]-propyl}-7-methyl-2-aza-spiro[4.5]-decane-1,3-dione (23) were classified to the Anticonvulsant Screening Program (ASP) 1 class. In addition, since the investigated compounds belong to a class of long-chain arylpiperazines, their serotonin 5-HT1A and 5-HT2A receptor affinity was determined. All the 2-OCH3 and 3-Cl derivatives were the most potent 5-HT1A receptor ligands (Ki = 24-143 and 70-107 nM, respectively), whereas the highest 5-HT2A affinity was observed for the unsubstituted and 3-Cl derivatives (Ki = 8-66 nM). No correlation between anticonvulsant and serotonergic activity was observed. PMID:15985716

Obniska, Jolanta; Ko?aczkowski, Marcin; Charakchieva-Minol, Sijka; Nedza, Krystyna; Dyba?a, Ma?gorzata; Bojarski, Andrzej J

2005-01-01

308

Antiallodynic Action of 1-(3-(9H-Carbazol-9-yl)-1-propyl)-4-(2-methyoxyphenyl)-4-piperidinol (NNC05-2090), a Betaine/GABA Transporter Inhibitor.  

PubMed

The GABAergic system in the spinal cord has been shown to participate in neuropathic pain in various animal models. GABA transporters (GATs) play a role in controlling the synaptic clearance of GABA; however, their role in neuropathic pain remains unclear. In the present study, we compared the betaine/GABA transporter (BGT-1) with other GAT subtypes to determine its participation in neuropathic pain using a mouse model of sciatic nerve ligation. 1-(3-(9H-Carbazol-9-yl)-1-propyl)-4-(2-methyoxyphenyl)-4-piperidinol (NNC05-2090), an inhibitor that displays moderate selectivity for BGT-1, had an antiallodynic action on model mice treated through both intrathecally and intravenous administration routes. On the other hand, SKF89976A, a selective GAT-1 inhibitor, had a weak antiallodynic action, and (S)-SNAP5114, an inhibitor that displays selectivity for GAT-3, had no antiallodynic action. Systemic analysis of these compounds on GABA uptake in CHO cells stably expressing BGT-1 revealed that NNC05-2090 not only inhibited BGT-1, but also serotonin, noradrenaline, and dopamine transporters, using a substrate uptake assay in CHO cells stably expressing each transporter, with IC50: 5.29, 7.91, and 4.08 ?M, respectively. These values were similar to the IC50 value at BGT-1 (10.6 ?M). These results suggest that the antiallodynic action of NNC05-2090 is due to the inhibition of both BGT-1 and monoamine transporters. PMID:24881960

Jinzenji, Ayako; Sogawa, Chiharu; Miyawaki, Takuya; Wen, Xue-Fang; Yi, Dan; Ohyama, Kazumi; Kitayama, Shigeo; Sogawa, Norio; Morita, Katsuya

2014-06-19

309

Design and synthesis of novel 2-(3-substituted propyl)-3-(2-methyl phenyl) quinazolin-4-(3H)-ones as a new class of H1-antihistaminic agents.  

PubMed

A series of novel 2-(3-substituted propyl)-3-(2-methyl phenyl) quinazolin-4-(3H)-ones were synthesized by the reaction of 2-(3-bromopropyl thio)-3-(2-methyl phenyl) quinazolin-4-(3H)-one with various amines. The starting material, 2-(3-bromopropyl thio)-3-(2-methyl phenyl) quinazolin-4-(3H)-one was synthesized from 2-methyl aniline. When tested for their in vivo H(1)-antihistaminic activity on conscious guinea pigs, all the test compounds protected the animals from histamine induced bronchospasm significantly. Compound 2-(3-(4-methylpiperazin-1-yl) propylthio)-3-(2-methyl phenyl) quinazolin-4(3H)-one (OT5) emerged as the most active compound (71.70% protection) of the series when compared to the reference standard chlorpheniramine maleate (70.09% protection). Compound OT5 shows negligible sedation (7%) compared to chlorpheniramine maleate (33%). Therefore, compound OT5 can serve as the leading molecule for further development into a new class of H(1)-antihistaminic agents. PMID:22074561

Alagarsamy, V; Parthiban, P

2013-02-01

310

Use of 1,3-diaminepropane-3-propyl grafted onto a silica gel as a sorbent for flow-injection spectrophotometric determination of copper (II) in digests of biological materials and natural waters  

NASA Astrophysics Data System (ADS)

The 1,3-diaminepropane-3-propyl-anchored silica gel (DAPPS) was successfully employed as a sorbent in a spectrophotometric flow system for the preconcentration of Cu 2+ in digests of biological materials (maize powder, soybean, citrus leaves, corn stalks) as well as water samples (river, stream, streamlet, springwater and well). The system presented a minicolumn packed with DAPPS, where the sample solution was passed through it for a period of time, and subsequently, an eluent solution, stripped-out the retained analyte which was further determined with DDTC at 460 nm. The better preconcentration conditions utilized were: 120 s loading, 60 s elution, 30 s regeneration of the column, loading flow rate 6.5 ml min -1, buffer solution for the preconcentration and regeneration of the column-borate buffer pH 8.5, elution flow rate 2.3 ml min -1, time of elution 60 s, eluent composition, 0.4 mol l -1 HNO 3. Under these conditions, the preconcentration factor obtained was 36, and the detection limit achieved was 8.4 ng ml -1 in water samples and 0.84 ?g g -1 in biological material. The maximum adsorption capacity of DAPPS to Cu 2+ was 0.49 mmol g -1 (31.1 mg g -1) obtained in a batch system. The recovery of copper in the water samples ranged from 96.9 to 102.4% and in the biological materials ranged from 97.0 to 102.6%.

de Moraes, Sandra V. M.; Brasil, Jorge L.; Milcharek, Caroline D.; Martins, Lucas C.; Laranjo, Marina T.; Gallas, Márcia R.; Benvenutti, Edílson V.; Lima, Eder C.

2005-11-01

311

Fluorescent Derivatives of ? Receptor Ligand 1-Cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (PB28) as a Tool for Uptake and Cellular Localization Studies in Pancreatic Tumor Cells  

PubMed Central

Fluorescent derivatives of ?2 high affinity ligand 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine 1 (PB28) were synthesized. NBD or Dansyl fluorescent tags were connected through a 5- or 6-atoms linker in two diverse positions of 1 structure. Good ?2 affinities were obtained when the fluorescent tag was linked to 5-methoxytetralin nucleus replacing the methyl function. NBD-bearing compound 16 displayed high ?2 affinity (Ki = 10.8 nM) and optimal fluorescent properties. Its uptake in pancreatic tumor cells was evaluated by flow cytometry showing that it partially occurs through endocytosis. In proliferating cells the uptake was higher supporting that ?2 receptors are markers of cell proliferation and that the higher is the proliferation, the stronger is the antiproliferative effect of ?2 agonists. Colocalization of 16 with subcellular organelles was studied by confocal microscopy: the greatest was in endoplasmic reticulum and lysosomes. Fluorescent ?2 ligands show their potential in clarifying the mechanisms of action of ?2 receptors.

Abate, Carmen; Hornick, John R.; Spitzer, Dirk; Hawkins, William G; Niso, Mauro; Perrone, Roberto; Berardi, Francesco

2011-01-01

312

A gas-phase crossed-beam study of OH produced in the radical-radical reaction of O((3)P) with iso-propyl radical (CH3)2CH.  

PubMed

The gas-phase radical-radical reaction dynamics of ground-state atomic oxygen [O((3)P)] with iso-propyl radicals, (CH(3))(2)CH, were investigated by applying a combination of high-resolution laser-induced fluorescence spectroscopy in a crossed-beam configuration and ab initio calculations. The nascent distributions of OH (X(2)?: ?'' = 0) from the major reaction channel O((3)P) + (CH(3))(2)CH ? C(3)H(6) (propene) + OH showed substantial internal excitations with a bimodal feature of low- and high-N'' components with neither spin-orbit nor ?-doublet propensities. Unlike previous kinetic results, proposed to proceed only through the direct H-atom abstraction process, on the basis of the population analysis and comparison with the statistical theory, the title reaction can be described in terms of two competing mechanisms at the molecular level: direct abstraction process and indirect short-lived addition-complex-forming process with a ratio of 1.25?:?1. PMID:21279211

Kang, Kyoo-Weon; Park, Min-Jin; Choi, Jong-Ho

2011-05-14

313

Efficacy of a novel, orally active GSK-3 inhibitor 6-Methyl-N-[3-[[3-(1-methylethoxy)propyl]carbamoyl]-1H-pyrazol-4-yl]pyridine-3-carboxamide in tau transgenic mice.  

PubMed

Neurofibrillary tangles (NFTs) composed of hyperphosphorylated and aggregated tau are common pathological characteristics in Alzheimer's disease (AD) and other tauopathies. Aberrant tau phosphorylation is an early and pivotal event in the pathogenesis of tauopathies, and since GSK-3 is a key factor implicated in aberrant tau phosphorylation, GSK-3 inhibition is expected to suppress tauopathy disease progression. In the present study, we report the efficacy of a newly discovered small molecule GSK-3 inhibitor, 6-methyl-N-[3-[[3-(1-methylethoxy)propyl]carbamoyl]-1H-pyrazol-4-yl]pyridine-3-carboxamide (compound A), to inhibit tau phosphorylation and to reduce the amount of pathological aggregated tau in JNPL3 mice that overexpress a mutant form of human tau. Compound A is a highly potent and selective inhibitor of GSK-3 with an IC(50) of 2 nM, with at least 230-fold lower potency against 27 other kinases. Oral administration of compound A resulted in a significant reduction of tau phosphorylation at several GSK-3 directed sites. Furthermore, chronic oral administration of compound A markedly reduced aggregated tau in old JNPL3 mice. These results suggest that a novel, orally active GSK-3 inhibitor, compound A, has potency in the prevention of tau pathology. PMID:19698704

Uno, Yumiko; Iwashita, Hiroki; Tsukamoto, Tetsuya; Uchiyama, Noriko; Kawamoto, Tomohiro; Kori, Masakuni; Nakanishi, Atsushi

2009-11-01

314

Crystal structure and physicochemical properties of crystalline form of 2'-O-{3-[(7-chloro-4-quinolinyl)amino]propyl}-9-deoxo-9a-methyl-9a-aza-9a-homoerythromycin A.  

PubMed

The intent of the study was to prepare and characterize crystalline form of 2'-O-{3-[(7-chloro-4-quinolinyl)amino]propyl}-9-deoxo-9a-methyl-9a-aza-9a-homoerythromycin A (1), a novel 15-membered azalide derivative with antimalarial activity. The crystalline material was prepared by crystallization from acetonitrile reproducible in high yield and purity. Single crystal X-ray studies, X-ray powder diffractometry, differential scanning calorimetry, thermogravimetric analysis, moisture adsorption, Karl Fischer titration, gas chromatography, scanning electron microscopy, optical microscopy, solubility, and solid-state and solution stability were conducted to investigate physicochemical properties of the existing crystalline form. Crystalline 1 is not hygroscopic, does not contain solvents, is physicochemically stable in solid state for up to 4 weeks, and is highly soluble at pH values below 6 and in biorelevant media (simulated gastric fluid, fed simulated intestinal fluid, and fasted simulated intestinal fluid). Solution stability studies (buffers and biorelevant media) indicated that this compound is stable in solutions at pH values 5-6, and that stability is influenced by pH and temperature. PMID:21394721

Fili?, Darko; Star?evi?, Kristina; Peši?, Dijana; Jurmanovi?, Stella; Meenan, Eugene; Spezzaferri, Alberto; ?ilovi?, Ivica; Prugove?ki, Biserka

2011-07-01

315

The metabolic fate of the dopamine agonist 2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin in rats after intravenous and oral administration. II. Isolation and identification of metabolites.  

PubMed

1. The in vivo metabolic pathways of 2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin (I) in rats have been established, using in vitro metabolism as a complementary technique. 2. All identified metabolites were conjugates. Glucuronidation at the phenolic group yields the major metabolite, accounting for 50% (i.v.) or 65% (oral) of the dose. The corresponding sulphate conjugate of I is virtually absent (less than 0.2% dose). 3. Hydroxylation of I, at the ortho position to the phenolic hydroxy group, yields 6-hydroxy-I (II), accounting for about 13% (i.v.) or 9% (oral) dose. This catechol is excreted, as a glucuronide, almost exclusively into the bile. Both the 5- and the 6-glucuronide of II were detected in about equal amounts. 4. Metabolism of I in vitro showed that under oxidative conditions, depropylation of I occurred. Conjugation of 3H-I in the presence of UDPGA or PAPS, was successful in yielding the glucuronide and sulphate conjugates. PMID:1971984

Gerding, T K; Drenth, B F; de Zeeuw, R A; Tepper, P G; Horn, A S

1990-05-01

316

Direct analysis of the dopamine agonist (-)-2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin hydrochloride in plasma by high-performance liquid chromatography using two-dimensional column switching.  

PubMed

A reversed-phase, two-dimensional, liquid chromatographic method incorporating column switching and electrochemical detection was used for the direct analysis of the dopamine (D2) agonist (-)-2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin hydrochloride in plasma. Sample work-up consisted of addition of internal standard, filtration, then direct injection of the plasma sample onto an internal surface reversed-phase (ISRP) guard column where the dopamine agonist and internal standard were separated from plasma proteins. An automated pneumatic valve was then used to switch to a stronger eluent which stripped the retained substances from the ISRP support onto a C18 analytical column where the analytes were separated from endogenous biological interferences. A dual-electrode electrochemical detector was used to minimize interferences and provide the desired sensitivity. The method has a detection limit of 1.5 ng/ml and requires a total assay time of 20 min per plasma sample. The method is linear from 1.5 to 1000 ng/ml and yielded greater than 80% drug recovery for plasma concentrations greater than 10 ng/ml. Precision for the method at 100 ng/ml yielded a relative standard deviation of 4.4%. Reproducibility was within 6.5% on a 20 ng/ml spiked plasma sample assayed on different days by different people. The method has successfully been applied to human plasma samples and for pharmacokinetic studies in rats and monkeys. PMID:1678747

Ruckmick, S C; Hench, B D

1991-04-19

317

Novel derivatives of 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (PB28) with improved fluorescent and ? receptors binding properties.  

PubMed

Despite the promising potentials of ?2 receptors in cancer therapy and diagnosis, there are still ambiguities related to the nature and physiological role of the ?2 protein. With the aim of providing potent and reliable tools to be used in ?2 receptor research, we developed a novel series of fluorescent ?2 ligands on the basis of our previous work, where high-affinity ?2 ligand 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)-n-propyl]piperazine (1, PB28) was used as the pharmacophore. Compared to the previous compounds, these novel ligands displayed improved fluorescence and ?2 binding properties, were ?2-specifically taken up by breast tumor cells, and were successfully employed in confocal microscopy. Compound 14, which was the best compromise between pharmacological and fluorescent properties, was successfully employed in flow cytometry, demonstrating its potential to be used as a tool in nonradioactive binding assays for studying the affinity of putative ?2 receptor ligands. PMID:24697311

Abate, Carmen; Niso, Mauro; Marottoli, Roberta; Riganti, Chiara; Ghigo, Dario; Ferorelli, Savina; Ossato, Giulia; Perrone, Roberto; Lacivita, Enza; Lamb, Don C; Berardi, Francesco

2014-04-24

318

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. ...

319

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 ...

320

Ascorbic Acid  

MedlinePLUS

Ascorbic acid is used to prevent and treat scurvy, a disease caused by a lack of vitamin C ... Ascorbic acid comes in extended-release (long-acting) capsules and tablets, lozenges, syrup, chewable tablets, and liquid drops ...

321

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.

322

Nucleobase-caged peptide nucleic acids: PNA/PNA duplex destabilization and light-triggered PNA/PNA recognition.  

PubMed

The 2-(o-nitrophenyl)-propyl (NPP) group is used as caging group to mask the nucleobases adenine and cytosine in N-(2-aminoethyl)glycine peptide nucleic acids (aeg-PNA). The adeninyl and cytosinyl nucleo amino acid building blocks Fmoc-a(NPP) -aeg-OH and Fmoc-c(NPP) -aeg-OH were synthesized and incorporated into PNA sequences by Fmoc solid phase synthesis relying on high stability of the NPP nucleobase protecting group toward Fmoc-cleavage, coupling, capping, and resin cleavage conditions. Removal of the nucleobase caging group was achieved by UV-LED irradiation at 365?nm. The nucleobase caging groups provided sterical crowding effecting the Watson-Crick base pairing, and thereby, the PNA double strand stabilities. Duplex formation can completely be suppressed for complementary PNA containing caging groups in both strands. PNA/PNA recognition can be completely restored by UV light-triggered release of the photolabile protecting group. PMID:23649726

Guha, Samit; Graf, Julia; Göricke, Björn; Diederichsen, Ulf

2013-07-01

323

Simultaneous determination of trace levels of ethylmercury and methylmercury in biological samples and vaccines using sodium tetra(n-propyl)borate as derivatizing agent.  

PubMed

Because of increasing awareness of the potential neurotoxicity of even low levels of organomercury compounds, analytical techniques are required for determination of low concentrations of ethylmercury (EtHg) and methylmercury (MeHg) in biological samples. An accurate and sensitive method has been developed for simultaneous determination of methylmercury and ethylmercury in vaccines and biological samples. MeHg and EtHg were isolated by acid leaching (H2SO4-KBr-CuSO4), extraction of MeHg and EtHg bromides into an organic solvent (CH2Cl2), then back-extraction into Milli-Q water. MeHg and EtHg bromides were derivatized with sodium tetrapropylborate (NaBPr4), collected at room temperature on Tenax, separated by isothermal gas chromatography (GC), pyrolysed, and detected by cold-vapour atomic fluorescence spectrometry (CV AFS). The repeatability of results from the method was approximately 5-10% for EtHg and 5-15% for MeHg. Detection limits achieved were 0.01 ng g-1 for EtHg and MeHg in blood, saliva, and vaccines and 5 ng g-1 for EtHg and MeHg in hair. The method presented has been shown to be suitable for determination of background levels of these contaminants in biological samples and can be used in studies related to the health effects of mercury and its species in man. This work illustrates the possibility of using hair and blood as potential biomarkers of exposure to thiomersal. PMID:17340078

Gibicar, Darija; Logar, Martina; Horvat, Nusa; Marn-Pernat, Andreja; Ponikvar, Rafael; Horvat, Milena

2007-05-01

324

Ionic liquid-functionalized silica for selective solid-phase extraction of organic acids, amines and aldehydes.  

PubMed

Three ionic liquid (IL)-functionalized silica materials, imidazolium, N-methylimidazolium and 1-alkyl-3-(propyl-3-sulfonate) imidazolium, were synthesised and applied in solid-phase extraction (SPE) of organic acids, amines and aldehydes, which are important compound families in atmospheric aerosol particles. 1-Alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica was tested as sorbent for SPE for the first time. The analytes were separated and detected by liquid chromatography-mass spectrometry (LC-MS). To confirm the results achieved by LC-MS, the acids were additionally determined by gas chromatography-mass spectrometry (GC-MS). The stability of the IL-functionalized silica materials was tested at low and high pH. The effect of the pH on the extraction was also informative of the retention mechanism of the materials. The results showed anion exchange to be the main interaction, but hydrophobic and ? interactions and hydrogen bonding also played a role in the extraction. Extraction efficiencies for organic acids ranged from 87 to 110%, except for cis-pinonic acid (19-29%). Lower extraction efficiencies for amines and aldehydes confirmed that anionic exchange was the predominant interaction. Comparisons made with two commercial SPE materials--silica-based strong anion exchange (SAX) and polymer-based mixed-mode anion exchange and reverse-phase (MAX)--showed the IL-functionalized materials to offer different selectivity and better extraction efficiency than SAX for aromatic compounds. Finally, the new materials were successfully tested in the extraction of an atmospheric aerosol sample. PMID:21925663

Vidal, Lorena; Parshintsev, Jevgeni; Hartonen, Kari; Canals, Antonio; Riekkola, Marja-Liisa

2012-02-24

325

Synthesis of disulfide esters of dialkylaminocarbothioic acid as potent, non-detergent spermicidal agents.  

PubMed

S,S'-[disulfanediylbis(dialkylaminopropane-2,1-diyl)]bis- (dialkylaminothiocarbamate) (14-31) were prepared and evaluated for the spermicidal activity and antifungal activity. Dialkyldithiocarbamates (1-5) were reacted with epichlorohydrin to give 1-dialkylaminocarbothioic acid S-[(2,3-epithio)propyl]ester (7-11), these on further reaction with a secondary amine gave S,S'-[disulfanediylbis(dialkylaminopropane-2,1-diyl)]bis- (dialkylaminothiocarbamate) (14-31). Some of these compounds (16, 19-21, 23, 30, 31) were found to be very potent spermicidal agents with marginal antifungal activity. Two compounds (20, 21) were 25 times more active than nonoxynol-9 (N-9), the spermicide currently in the market. PMID:17765548

Dwivedi, Anil Kumar; Sharma, Vishnu Lal; Kumaria, Niharika; Kiran Kumar, S T V S; Srivastava, Pradeep Kumar; Ansari, Abdul Haq; Maikhuri, Jagdamba Prasad; Gupta, Gopal; Dhar, Janak Dulari; Roy, Raja; Joshi, Bhawani Shankar; Shukla, Praveen Kumar; Kumar, Manish; Singh, Satyawan

2007-11-01

326

Analyzing poly(3-hexyl-thiophene):1-(3-methoxy-carbonyl)propyl-1-phenyl-(6,6)C61 bulk-heterojunction solar cells by UV-visible spectroscopy and optical simulations  

NASA Astrophysics Data System (ADS)

A nondestructive method for assessing the thickness of the photoactive layer in poly(3-hexyl-thiophene):1-(3-methoxy-carbonyl)propyl-1-phenyl-(6,6)C61 (P3HT:PCBM) solar cells is reported. In the approach the absorption spectrum of the solar cell as derived by optical simulations is fitted to the corresponding measured spectrum, varying only the P3HT:PCBM layer thickness. Within the 50-250 nm thickness range, a linear correlation between the position of a certain spectral minimum and the P3HT:PCBM layer thickness is shown, based on simulated absorption spectra. As an initial application, absorption spectra for 240 P3HT:PCBM solar cells prepared at four different spin-coating speeds were recorded, and the average P3HT:PCBM layer thickness estimated for each spin-coating speed. The simulated fraction of light absorbed in the P3HT:PCBM layer of the solar cells is compared with the P3HT:PCBM absorption spectra measured for films spin coated on simpler substrate types. The latter spectra cannot account for the light harvested in the photoactive layer of P3HT:PCBM solar cells because of substantial optical interference in the solar cells. The measured short circuit current densities Jsc for the solar cells vary with the spin-coating speed in a manner confirmed by optical simulations of the maximal short circuit current densities. The measured efficiencies follow the same pattern. On average the measured Jsc is 1-2 mA/cm2 below the simulated maximal short circuit current densities. Based on the resemblance of the measured and simulated absorption spectra such difference can be attributed to recombination exclusively.

Sylvester-Hvid, Kristian O.; Ziegler, Tobias; Riede, Moritz K.; Keegan, Nicholas; Niggemann, Michael; Gombert, Andreas

2007-09-01

327

Photodegradation of metolachlor: isolation, identification, and quantification of monochloroacetic acid.  

PubMed

The photolysis of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] in a sunlight simulator under actinic radiation was investigated. The focus of the study was to determine the extent of monochloroacetic acid (MCA) production. MCA was concentrated and derivatized from photolysate as the n-propyl ester using propanol and sulfuric acid and then identified as the ester using GC/MS and GC/ECD. On the basis of regression analysis, it was shown that the direct photodegradation of approximately 10 microM metolachlor followed pseudo-first-order kinetics with respect to the metolachlor concentration, and the half-life of the herbicide ( approximately 74 h) was independent of the pH of the medium. Photolysis in synthetic field water (SFW) resulted in a significant reduction of photolysis time (t(1/2) approximately 9 h). Direct photolysis experiments indicate a 5.19 +/- 0.81% (n=3) conversion of metolachlor to MCA, while photolysis in synthetic field water and in a Don River water sample resulted in 29.8 +/- 4.6% (n = 3) and 12.6 +/- 4.1% (n = 3) conversion, respectively; MCA was shown to be hydrolytically stable over the time course of the photoreaction. The photodegradation of alachlor, butachlor and a model chloroacetanilide, 2-chloro-N-methylacetanilide, in SFW were also investigated. PMID:10725179

Wilson, R I; Mabury, S A

2000-03-01

328

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

329

Gas-Phase Reactivity of Carboxylic Acid Functional Groups with Carbodiimides  

PubMed Central

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.

2012-01-01

330

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

331

Acid clusters  

SciTech Connect

Molecular clusters can be considered to be the smallest size range of an aerosol particle size distribution. Nucleation from the gas phase to particles or droplets involves the formation of clusters in the initial stages. Consequently, knowledge of the properties and formation of clusters containing acids contribute to an understanding of acid rain. This paper presents an overview of results obtained in the laboratory on the formation and stability of both neutral and ionized acid clusters. With free jet expansion techniques, the authors have produced clusters of aqueous nitric acid, aqueous hydrochloric acid, aqueous sulfuric acid, acetic acid and aqueous sulfur dioxide. For analogy to buffering, the formation of clusters containing ammonia have also been examined. These have included ammonia with aqueous nitric acid, hydrogen sulfide and sulfur dioxide. The basic experiment involves expansion of vapor through a nozzle, collimation of the jet with a skimmer to form a well-directed molecular beam, and detection of clusters via electron impact ionization and mass spectrometry. Some variations include the introduction of a reactive gas into vacuum near the expansion as described elsewhere and the implementation of an electrostatic quadrupolar field to examine the polarity of the neutral clusters.

Keesee, R.G.; Castleman, A.W. Jr.

1986-04-01

332

Domoic Acid  

NSDL National Science Digital Library

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

Bailey, Christina; Kohlen, Corinne

2010-02-10

333

Acid rain  

Microsoft Academic Search

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

R. E. Ghelardi; B. L. Murphy

2009-01-01

334

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.

335

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

336

Usnic acid.  

PubMed

Since its first isolation in 1844, usnic acid [2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzo-furandione] has become the most extensively studied lichen metabolite and one of the few that is commercially available. Usnic acid is uniquely found in lichens, and is especially abundant in genera such as Alectoria, Cladonia, Usnea, Lecanora, Ramalina and Evernia. Many lichens and extracts containing usnic acid have been utilized for medicinal, perfumery, cosmetic as well as ecological applications. Usnic acid as a pure substance has been formulated in creams, toothpaste, mouthwash, deodorants and sunscreen products, in some cases as an active principle, in others as a preservative. In addition to antimicrobial activity against human and plant pathogens, usnic acid has been shown to exhibit antiviral, antiprotozoal, antiproliferative, anti-inflammatory and analgesic activity. Ecological effects, such as antigrowth, antiherbivore and anti-insect properties, have also been demonstrated. A difference in biological activity has in some cases been observed between the two enantiomeric forms of usnic acid. Recently health food supplements containing usnic acid have been promoted for use in weight reduction, with little scientific support. The emphasis of the current review is on the chemistry and biological activity of usnic acid and its derivatives in addition to rational and ecologically acceptable methods for provision of this natural compound on a large scale. PMID:12453567

Ingólfsdóttir, K

2002-12-01

337

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

338

Acid rain  

SciTech Connect

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 sufficiently concentrated, these acids can kill fish and damage material structures. Under certain circumstances they may reduce crop and forest yields and cause or aggravate respiratory diseases in humans. During the summer, especially, pollutants tend to collect over the Great Lakes in high pressure systems. Since winds typically are westerly and rotate clockwise around high pressure systems, the pollutants gradually are dispersed throughout the eastern part of the continent.

Sweet, W.

1980-06-20

339

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

340

The preparation, characterization and X-ray structural analysis of tetrakis [1-methyl-3-(2-propyl)-2(3 H )-imidazolethione]zinc(II) tetrafluoroborate and tetrakis [1-methyl-3-(1-butyl)-2(3 H )- imidazolethione]zinc(II) tetrafluoroborate  

Microsoft Academic Search

Two compounds, [Zn(mipit)4][BF4]2 (1) and [Zn(mnbit)4][BF4]2 (2) have been synthesized and characterized via standard solid and solution state methods including single crystal X-ray crystallography (mipit: 1-methyl-3-(2-propyl)-2(3H)-imidazolethione and mnbit: 1-methyl-3-(1-butyl)-2(3H)-imidazolethione). Compound 1 crystallizes in monoclinic space group P21\\/n with a = 11.804(2) , b = 16.710(3) , c = 25.763(5) , ? = 90.14(3) and Z = 4, whereas compound 2 crystallizes in tetragonal

Daniel J. Williams; Javier J. Concepcion; Marina C. Koether; Kimberly A. Arrowood; Angela L. Carmack; Tiffany G. Hamilton; Stacy M. Luck; Madeleine Ndomo; C. Ryan Teel; Donald VanDerveer

2006-01-01

341

Folic Acid  

MedlinePLUS Videos and Cool Tools

... register. I'm interested in: Pregnancy Baby growth & care Research Volunteer opportunities Advocacy in government For health ... acid During your pregnancy Your pregnant body Prenatal care Eating and nutrition Physical activity Emotional and life ...

342

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...

343

Alternative thermodiffusion interface for simultaneous speciation of organic and inorganic lead and mercury species by capillary GC-ICPMS using tri-n-propyl-lead chloride as an internal standard.  

PubMed

An alternative thermodiffusion interface (TDI) was designed and constructed for the effective online coupling of capillary gas chromatography (cGC) and inductively coupled plasma mass spectrometry (ICPMS). Pb(2+), (CH3)3Pb(+), (C2H5)3Pb(+), Hg(2+), CH3Hg(+) and C2H5Hg(+) were derived as Pb(C4H9)4, (CH3)3PbC4H9, (C2H5)3PbC4H9, (C4H9)2Hg, CH3HgC4H9, and C2H5HgC4H9 when butyl magnesium bromide was employed as a derivatization reagent for a proof-of-concept study, avoiding the loss of their species specific information. All these derivatives together with the neutral fully saturated (CH3)4Pb and (C2H5)4Pb could be quantitatively separated within 7 min using a 15 m long capillary column, allowing the determination and speciation of organic and inorganic Pb and Hg species in a single run. The method detection limits (3sigma) for Me4Pb, Et4Pb, Me3Pb(3+), Pb(2+), MeHg(+), EtHg(+), and Hg(2+) are 0.07, 0.06, 0.04, 7.0, 0.09, 0.1, and 0.2 pg g(-1), respectively. Moreover, tri-n-propyl-lead chloride was synthesized and used as an alternative internal standard for the accurate and simultaneous speciation analysis of Pb and Hg in complicated environmental and biological samples for the first time. This cGC-TDI-ICPMS method was validated by analyzing Pb and Hg species in certified reference materials and then was applied to simultaneous speciation analysis of Pb and Hg in real-life samples. It is expected that these approaches can be extended to the speciation of other organometallic compounds after suitable modifications and so will aid in monitoring the occurrence, pathways, toxicity, and/or biological effects of these compounds in the environment and in organisms. PMID:18576666

Yan, Dong; Yang, Limin; Wang, Qiuquan

2008-08-01

344

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

345

Topical drug delivery from thin applications: theoretical predictions and experimental results.  

PubMed

Stainless-steel templates of various thicknesses (75, 200, 800, and 1600 microns) were used to apply propylene glycol/water gels containing methyl or propyl p-aminobenzoates to silicone rubber membranes, and drug delivery was studied with the use of the Bronaugh diffusion cell under conditions in which the drug was initially in thermodynamic equilibrium with respect to the application and membrane. Theoretical diffusion profiles were generated with the use of a model which assumes that diffusional gradients exist within the application. To use the model equation, previously derived for the initial condition in which the drug is in thermodynamic equilibrium with respect to the application and membrane, drug diffusivity in both the application and the membrane and the drug's membrane/vehicle partition coefficient were independently determined. In general, agreement between experimental and theoretical results was within 25%. PMID:2281035

Addicks, W; Weiner, N; Flynn, G; Curl, R; Topp, E

1990-10-01

346

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

347

STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS  

PubMed Central

Sensitization of guinea pigs to picric acid was obtained by application of oil solutions to the skin, preferably on inflamed sites or by treatment with a compound of picric acid with n-butyl-p-aminobenzoate. The lesions obtained in sensitive animals on superficial administration bore resemblance to human eczema. It seems probable that picric acid sensitization is an instance where a substance does not sensitize directly but after conversion into a more reactive compound, a principle which should be of wider application to instances where the original substance does not readily form conjugates.

Landsteiner, K.; Di Somma, A. A.

1940-01-01

348

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

349

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.

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

2012-01-01

350

Synthesis of 25-hydroxyvitamin D sub 3 3. beta. -3 prime -(N-(4-azido-2-nitrophenyl)amino)propyl ether, a second-generation photoaffinity analogue of 25-hydroxyvitamin D sub 3 : Photoaffinity labeling of rat serum vitamin D binding protein  

SciTech Connect

Vulnerability of 25-hydroxy-(26,27-{sup 3}H)vitamin D{sub 3} 3{beta}-N-(4-azido-2-nitrophenyl)glycinate, a photoaffinity analogue of 25-hydroxyvitamin D{sub 3} (25-OH-D{sub 3}) toward standard conditions of carboxymethylationin promoted the authors to synthesize 25-hydroxyvitamin D{sub 3} 3{beta}-3{prime}-(N-(4-azido-2-nitrophenyl)amino)propyl ether (25-ANE), a hydrolytically stable photoaffinity analogue of 25-OH-D{sub 3}, and 25-hydroxyvitamin D{sub 3} 3{beta}-3{prime}-(N-(4-azido-2-nitro-(3,5-{sup 3}H)phenyl)amino)propyl ether ({sup 3}H-25-ANE), the radiolabeled counterpart of 25-ANE competes for the 25-OH-D{sub 3} binding site in rat serum vitamin D binding protein (rDBP). On the other hand, UV exposure of a sample of purified rat DBP (rDBP), preincubated in the dark with {sup 3}H-25-ANE, covalently labeled the protein. However, very little covalent labeling was observed in the absence of UV light or in the presence of a large excess of 25-OH-D{sub 3}. These results provide strong evidence for the covalent labeling of the 25-OH-D{sub 3} binding site in rDPB by {sup 3}H-25-ANE.

Ray, R.; Holick, M.F. (Boston Univ. School of Medicine, MA (USA)); Bouillon, R.; Van Baelen, H. (Laboratorium voor Experimentele Geneeskunde en Endocrinologie, Gasthuisberg, Leuven (Belgium))

1991-05-14

351

Stearic Acid  

ERIC Educational Resources Information Center

A chemical laboratory information profile (CLIP) is presented for the chemical, stearic acid. The profile lists the chemical's physical and harmful characteristics, exposure limits, and symptoms of major exposure, for the benefit of teachers and students, who use the chemical in the laboratory.

Young, Jay A.

2004-01-01

352

Amino Acids  

NSDL National Science Digital Library

The Featured Molecules this month are the 20 standard α-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.

353

Ethacrynic Acid  

MedlinePLUS

... or any of the ingredients in ethacrynic acid tablets. Ask your doctor or pharmacist for a list of the ingredients.tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements and herbal products you are taking or plan to take. ...

354

Tranexamic Acid  

MedlinePLUS

... or any of the ingredients in tranexamic acid tablets. Ask your pharmacist for a list of the ingredients.tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. ...

355

In situ derivatization hollow fiber mediated liquid phase microextraction of alkylphosphonic acids from water.  

PubMed

Alkylphosphonic acids (APAs), particularly the methyl-, ethyl-, isopropyl- and n-propyl-phosphonic acids are important markers of extremely toxic nerve agents. Hence, their detection and identification is of vital importance to verification of chemical weapons convention (CWC). Verification analysis of CWC requires development of fast, reliable, simple and reproducible sample preparation methods of water and soil samples. Present investigation is focused on the optimization of alkylation of APAs in water with subsequent extraction of alkylated acids by hollow fiber liquid phase microextraction (HF-LPME). This simple and sensitive sample preparation of APAs from water offered better recoveries in comparison to conventionally used extraction technique. Under optimized conditions, the APAs were detected at the concentration of 0.5-0.75 microg/mL with S/N ratio > or = 5, whereas the LODs for alkyl APAs (monobasic APAs) were achieved up to 0.1 microg/mL. The developed method was finally tested with water samples supplied in 19th official proficiency test conducted by the OPCW. PMID:17174319

Pardasani, Deepak; Kanaujia, Pankaj K; Gupta, A K; Tak, Vijay; Shrivastava, R K; Dubey, D K

2007-02-01

356

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

357

Carbonate acidizing  

SciTech Connect

The authors present the first quantitative study and complete model of the wormholing phenomenon, leading to a means of predicting and optimizing carbonate acidizing treatments. Laboratory experiments on a gypsum model system and computer simulations show that for a given geometry, wormholes can be quantified by a unique parameter, their equivalent hydraulic length. The behavior of this quantifying parameter vs. all the system parameters is studied and allows the quantitative prediction of the efficiency of an acidizing treatment. This study highlights the fractal nature of the phenomenon, which is accounted for in the equations, and the strong effect of the sample geometry. Three types of etching can be obtained: compact, wormhole type, or homogeneous. The optimum conditions for achieving the best skin decrease correspond to the creation of wormholes and can then be defined in terms of fluid reactivity and injection rate.

Daccord, G.; Touboul, E.; Lenormand, R.

1989-02-01

358

Levulinic acid  

PubMed Central

The title compound (systematic name: 4-oxo­penta­noic acid), C5H8O3, is close to planar (r.m.s. deviation = 0.0762?Å). In the crystal, the mol­ecules inter­act via O—H?O hydrogen bonds in which the hy­droxy O atoms act as donors and the ketone O atoms in adjacent mol­ecules as acceptors, forming C(7) chains along [20-1].

Hachula, Barbara; Polasz, Anna; Dzida, Marzena; Nowak, Maria; Kusz, Joachim

2013-01-01

359

Domoic Acid  

NSDL National Science Digital Library

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

Inchem; Safety, International P.

360

Photostabilization of doxorubicin hydrochloride with radioprotective and photoprotective agents: Potential mechanism for enhancing chemotherapy during radiotherapy  

SciTech Connect

p-Aminobenzoic acid (PABA), urocanic acid, and sodium urate were found to significantly enhance the photostability of doxorubicin hydrochloride (adriamycin, (ADR)). d1-Methionine, thiourea, and glycine also increased the photostability of this drug, but to a lesser degree. Sodium thiosulfate on the other hand, was found to be detrimental to the photostability of ADR. The photostabilizing effect of PABA was found to increase with increase of its concentration and was influenced by the pH and the buffer species of the vehicle. The findings would have an impact on the enhancement of therapeutic efficacy of adriamycin when administered during radiation therapy.

Habib, M.J.; Asker, A.F.

1989-11-01

361

Synthesis and properties of new highly soluble poly(amide-ester-imide)s containing poly(ethylene glycol) as a soft segment  

Microsoft Academic Search

In this study, a new class of highly soluble poly(amide-ester-imide)s (PAEI)s contains poly(ethyleneglycol) (PEG) as hydrophilic\\u000a and soft segment were prepared. Poly(ethylene glycol)-bis-(N-trimellitylimido-4-phenyl carboxylic acid) (3) as a novel diacid monomer was synthesized via two step. The reaction of poly(ethylene glycol) (PEG 6000) with trimellitic\\u000a anhydride chloride yield poly(ethylene glycol)-bis-trimellitic anhydride (1). The reaction of dianhydride 1 with p-aminobenzoic acid

Majid Kolahdoozan; Razieh Mirsafaei; Shadpour Mallakpour

362

Synthesis, antimicrobial and anticancer activity of new thiosemicarbazone derivatives.  

PubMed

Thiosemicarbazones of p-aminobenzoic acid (PABA) were synthesized and tested for their antimicrobial and anticancer activity. Hydroxamate derivatives 4a-4l were found to have better antimicrobial and anticancer activity than their acid counterpart. Compound 4d was found to have good antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis with IC(50) value of about 1 µM. Compound 4f showed potent antifungal activity against Candida albicans (IC(50) ?= 1.29 µM) and compound 4h showed potent anticancer activity (IC(50) ?= 0.07 µM). PMID:21290424

Kulandaivelu, Umasankar; Padmini, Valisakka Gari; Suneetha, Kyatham; Shireesha, Boyapati; Vidyasagar, Jannu Vincent; Rao, Tadikonda Rama; K N, Jayaveera; Basu, Arijit; Jayaprakash, Venkatesan

2011-02-01

363

Nutritional interdependence between Thermoanaerobacter thermohydrosulfuricus and Clostridium thermocellum  

Microsoft Academic Search

Thermoanaerobacter thermohydrosulfuricus strain YM3 andClostridium thermocellum strain YM4, obtained originally as a stable coculture, required yeast extract to grow separately. Cell-free broths ofT. thermohydrosulfuricus strain YM3 andC. thermocellum strain YM4 monocultures replaced yeast extract in supporting the growth of strains YM4 and YM3, respectively.T. thermohydrosulfuricus strain YM3 produced vitamin B6, B12 analog(s),p-aminobenzoic acid and folic acid, which were required byC.

Yutaka Mori

1995-01-01

364

Fatty acids as natural specific inhibitors of the proto-oncogenic protein Shp2.  

PubMed

Src homology-2 domain-containing protein tyrosine phosphatase (Shp2), a novel proto-oncogenic protein, is an important target in cancer therapy research. Approximately 2000 plant extracts were screened to find its natural specific inhibitors, with the ethyl acetate (EtOAc) active extract of the root of Angelica dahurica showing considerable inhibitory effects (IC(50)=21.6 mg/L). Bioguided isolation of EtOAc extract led to 13 compounds, including 10 fatty acids and derivatives. All these compounds were isolated from the plant for the first time. The inhibitory effects of these compounds on the enzyme activities of Shp2, VH1-related human protein (VHR), and hematopoietic protein tyrosine phosphatase (HePTP) were investigated. 8Z,11Z-Feptadecadienoic acid (4), 14Z,17Z-tricosadienoic acid (5), caffeic acid (9), and 2-hydroxy-3-[(1-oxododecyl) oxy]propyl-?-d-glucopyranoside (11) showed considerable selective inhibition of Shp2 activity. After treatment of HepG2 cells with the compounds, only compound 5, a polyunsaturated fatty acid, strongly induced poly (ADP-ribose) polymerase (PARP) cleavage in a dose- and time-dependent manner and increased the activities of caspase-3, caspase-8, and caspase-9 at 100 ?M. Compound 5 also inhibited colony formation of HepG2 cells in a dose-dependent manner. Thus, this study reported fatty acids as specific Shp2 inhibitors and provided the molecular basis of one active compound as novel potential anticancer drug. PMID:21962577

Liu, Dongping; Kong, Guiping; Chen, Quan Cheng; Wang, Guanghui; Li, Jie; Xu, Yang; lin, Ting; Tian, Yingpu; Zhang, Xiaokun; Yao, Xinsheng; Feng, Gensheng; Lu, Zhongxian; Chen, Haifeng

2011-11-15

365

3,5-Dicaffeoylquinic acid isolated from Artemisia argyi and its ester derivatives exert anti-leucyl-tRNA synthetase of Giardia lamblia (GlLeuRS) and potential anti-giardial effects.  

PubMed

An aqueous ethanol extract of Artemisia argyi inhibited the aminoacylation activity of LeuRS from Giardia lamblia (GlLeuRS). The bioassay-guided fractionation of the extract led to the isolation of 3,5-dicaffeoylquinic acid (1), with an IC?? of 5.82 ?g/mL. The ester derivatives of 1 were also found to possess strong anti-GlLeuRS effects, with IC?? values of 1.79, 5.51 and 2.56 ?g/mL respectively. Anti-giardial assay showed that the derivatives, especially 3,5-dicaffeoylquinic acid propyl ester (4) (IC??=4.62 ?g/mL), were effective at killing G. lamblia. PMID:22668973

Zhang, Yan-Hong; Xue, Mei-Qin; Bai, Yuan-Chao; Yuan, Hui-Hui; Zhao, Hong-Li; Lan, Min-Bo

2012-10-01

366

Metal extraction by silyl-substituted diphosphonic acids. Part 2. Effect of alkyl bridge length on aggregation and metal ion extraction behavior.  

SciTech Connect

In an ongoing effort to determine the relationship between structure and function in diphosphonic acids, the aggregation and solvent extraction chemistry of four novel silicon-substituted diphosphonic acids, P,P'-di[3-(trimethylsilyl)-1-propyl] propylene- (H{sub 2}DTMSP[PrDP]), butylene- (H{sub 2}DTMSP[BuDP]), pentylene- (H{sub 2}DTMSP[PDP]), and hexylene diphosphonic acid (H2DTMSP[HDP]), were investigated. Vapor pressure osmometry indicates that H{sub 2}DTMSP[PrDP] and H{sub 2}DTMSP[PDP] are dimeric in toluene at 25 C, while H{sub 2}DTMSP[BuDP] and H{sub 2}DTMSP[HDP] are primarily trimeric and hexameric, respectively. The solvent extraction of selected alkaline earth cations (Ca, Sr, and Ba) and representative tri-, tetra-, and hexavalent actinides [Am(III), Th(IV), and U(VI)], from nitric acid solutions into o-xylene solutions of the ligands has been studied and compared to results reported previously for some analogous di(2-ethylhexyl)-substituted diphosphonic acids. Differences observed in the magnitude of distribution ratios, based on the number of bridging methylene groups, have been explained considering factors such as ligand aggregation, chelate ring size, P=O basicity (qualitatively determined by 31P nuclear magnetic resonance and infrared spectroscopy), and the relative acidities of the ligands.

McAlister, D. R.; Dietz, M. L.; Chiarizia, R.; Zalupski, P. R.; Herlinger, A. W.; Chemistry; Loyola Univ.

2002-01-01

367

Vasoactive effects of eicosapentaenoic acid on isolated vascular smooth muscle.  

PubMed

Dietary intake of unsaturated fatty acid of eicosapentaenoic acid (EPA) is thought to reduce the size and incidence of myocardial infarction. These beneficial effects are postulated to be due to chronic antithrombotic properties of EPA itself. We studied the possible direct effects of EPA on vascular smooth muscle as well as the ability of EPA to modify the vasoactivity of constrictor mediators in rabbit and cat aortic rings and isolated cat coronary arteries. EPA concentration-dependently (30 to 300 microM) relaxed rabbit and cat aortic rings having an intact endothelium, while EPA did not show any significant vasodilator effects on rings without an endothelium. This EPA-induced vasorelaxation was not altered by the cyclooxygenase inhibitor ibuprofen, but was totally abolished by the guanylate cyclase inhibitor methylene blue, indicating an endothelium-dependent smooth muscle relaxation mechanism. In isolated perfused cat coronary arteries, EPA (3 to 300 microM) exerted a dilator effect which was endothelium-independent and not affected by ibuprofen. The response was attenuated by propyl gallate, a lipoxygenase inhibitor. EPA also inhibited leukotriene (LT) C4, (50 nM) and LTD4 (50 nM)-induced vasoconstriction of isolated cat coronary arteries ranging from a blockade of 10% to 15% (P less than 0.05) at 3 microM of EPA to a blockade of 89% to 93% (P less than 0.01) at 300 microM. In contrast, the thromboxane analog, CTA2, induced coronary constriction was not significantly altered by EPA. Thus, EPA produces endothelium-dependent relaxation in rabbit and cat aorta and endothelium-independent vasodilation in cat coronary arteries (i.e., intact vessels or helical strips). Moreover, EPA exerts acute anti-leukotriene actions in coronary arteries. In the case of long-term dietary intake of EPA, these actions may contribute to the protective action of EPA in myocardial ischemia. PMID:3038070

Yanagisawa, A; Lefer, A M

1987-01-01

368

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.

369

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 ...

370

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 ...

371

Catalyst-substrate adducts in asymmetric catalytic hydrogenation. Crystal and molecular structure of (((R,R)-1,2-bis(phenyl-o-anisoylphosphino)ethane)(methyl (Z)-. beta. -propyl-. alpha. -acetamidoacrylate))rhodium tetrafluoroborate, (Rh(DIPAMP)(MPAA))BF sub 4  

SciTech Connect

(Rh(R,R-DIPAMP)(MeOH){sub 2}){sup +} (DIPAMP = 1,2-bis(phenyl-o-anisoylphosphino)ethane), which serves as an asymmetric hydrogenation catalyst for enamides, reacts with methyl (Z)-{beta}-propyl-{alpha}-acetamidoacrylate (MPAA) to form the 1:1 adduct, (Rh(R,R-DIPAMP)(MPAA)){sup +} (1), with a binding constant of 1.4 {times} 10{sup 4} M{sup {minus}1} at 25{degree}C. Crystals of the BF{sub 4} salt of the predominant diastereomer of 1 were isolated and subjected to single-crystal X-ray analysis. The structure of 1 resembles those deduced previously for rhodium ((1,2-bis(diphenylphosphino)ethane)(methyl(Z)-{alpha}-acetamidocinnamate))tetrafluoroborate and rhodium ((2S,3S)-2,3-bis(diphenylphosphino)butane(ethyl (Z)-{alpha}-acetamideocinnamate)) perchlorate.

McCulloch, B.; Halpern, J. (Univ. of Chicago, IL (USA)); Thompson, M.R. (Monsanto Co., St. Louis, MO (USA)); Landis, C.R. (Univ. of Colorado, Boulder (USA))

1990-05-01

372

Monoamine concentrations changes in the PTU-induced hypothyroid rat brain and the ameliorating role of folic acid.  

PubMed

Thyroid hormones are recognized as the key metabolic hormones that play a critical role in the development of central nervous system (CNS) throughout life. The present study was designed to determine the changes in brain monoamine concentrations in 6-n-propyl thiouracil (PTU)-induced hypothyroid rats, in addition to the ameliorating role of folic acid treatment. Fifty male albino rats were equally divided into five groups; first and second groups were the control and folic acid groups, respectively, while the third group was the hypothyroid group in which the rats received PTU in drinking water for 6 weeks. The fourth and fifth groups were co- and post-treated folic acid groups with hypothyroid rats, respectively. Our results revealed that serotonin and norepinephrine concentrations were significantly decreased in the hypothalamus and cortex, while it significantly increased in the hippocampus of hypothyroid rats when compared with control group. Serotonin and norepinephrine concentrations were decreased in hypothalamus and cortex in co- and post-treated folic acid groups with hypothyroid rats, while the concentration of dopamine were significantly increased in the hypothalamus and hippocampus of the hypothyroid rats and co-treated folic acid group with hypothyroid rats. In cortex, the dopamine concentration was significantly increased in hypothyroid rats and post-treated folic acid group with hypothyroid rats, while it significantly decreased in co-treated folic acid group with hypothyroid rats when compared with the control group. Also, our results revealed that, folic acid treatment was better if it is administered as an adjuvant after returning to the euthyroid state by withdrawing PTU from the drinking water. PMID:21478293

Tousson, E; Ibrahim, W; Arafa, N; Akela, M A

2012-03-01

373

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

374

Synthesis and Photophysical Properties of the 2-(3-(2-Alkyl-6,8-diaryl-4-oxo-1,2,3,4-tetrahydroquinazolin-2-yl)propyl)-6,8-diarylquinazolin-4(3H)-ones.  

PubMed

Iodine-catalyzed condensation of 2-amino-3,5-dibromobenzamide with cyclohexane-1,3-dione derivatives in refluxing toluene afforded the corresponding bisquinazolinones. Suzuki-Miyaura cross-coupling of the latter with arylboronic acids afforded tetraarylbisquinazolinones. The electronic absorption and emission properties of these tetraarylbisquinazolinones were measured in dimethylsulfoxide (DMSO) and acetic acid by means of UV-Vis and fluorescence spectroscopic techniques in conjunction with quantum chemical methods to understand the influence of substituents on intramolecular charge transfer (ICT). PMID:25006782

Mmonwa, Mmakwena M; Mphahlele, Malose J; El-Hendawy, Morad M; El-Nahas, Ahmed M; Koga, Nobuaki

2014-01-01

375

Photophysical properties of lanthanide hybrids covalently bonded to functionalized MCM-41 by modified aromatic carboxylic acids.  

PubMed

MCM-41 mesoporous silica has been functionalized with aromatic carboxylic acids salicylic acid (Sal) and 2-hydroxyl-3-methylbenzoic acid (HMBA) through co-condensation approach of tetraethoxysilane (TEOS) in the presence of the cetyltrimethylammonium bromide (CTAB) surfactant as a template. Organic ligands salicylic acid or 2-hydroxyl-3-methylbenzoic acid grafted to the coupling agent 3-(triethoxysilyl)-propyl isocyanate (TEPIC) was used as the precursor for the preparation of an organic-inorganic hybrid materials. Novel organic-inorganic mesoporous luminescent hybrid containing Ln(3+) (Tb(3+), Eu(3+)) complexes covalently attached to the functionalized ordered mesoporous MCM-41, which were designated as Ln-Sal-MCM-41 and Ln-HMBA-MCM-41, respectively, were obtained by sol-gel process. The luminescence properties of these resulting materials were characterized in detail, and the results reveal that luminescent mesoporous materials have high surface area, uniformity in the mesopore structure and good crystallinity. Moreover, the mesoporous material covalently bonded Tb(3+) complex (Tb-Sal-MCM-41 and Tb-HMBA-MCM-41) exhibit the stronger characteristic emission of Tb(3+) and longer lifetime than the corresponding Eu-containing materials Eu-Sal-MCM-41 and Eu-HMBA-MCM-41 due to the triplet state energy of modified organic ligands Sal-TEPIC and HMBA-TEPIC match with the emissive energy level of Tb(3+) very well. In addition, the luminescence lifetime and emission quantum efficiency of (5)D(0) Eu(3+) excited state also indicates the efficient intramolecular energy transfer process in Tb-SAL-MCM-41 and Tb-HMBA-MCM-41. PMID:18649125

Li, Ying; Yan, Bing

2009-03-01

376

Reaction pathways for butanoic acid decarboxylation on the (111) surface of a Pd nanoparticle  

NASA Astrophysics Data System (ADS)

Many-electron theory is applied to investigate decarboxylation of butanoic acid on the (111) surface of a Pd42 nanoparticle. Butanoic acid adsorbs weakly as an intact molecule (?H = - 28 kJ/mol) with the sbnd COOH moiety nearly parallel to the surface. In comparison, dissociative adsorption of butanoic acid to form surface butanoate (Prsbnd COO) species and adsorbed H is exothermic by only 5 kJ/mol. Pathways for propane and CO2 formation are presented starting from adsorbed butanoic acid, Prsbnd COO (ads) and a Rsbnd CHsbnd COO (R = C2H5) surface intermediate. An intramolecular pathway involves rotating the H of sbnd COOH toward the target (alpha) carbon. Following a series of bond distortions, the H is close enough to the target C to form a stretched Hsbnd C bond. After propane begins to form, CO2 linearizes and Csbnd C dissociation is energetically favorable and rapid. Reaction of Prsbnd COO (ads) and H (ads) also results in direct formation of propane and CO2. The energy barriers for H insertion are ~ 100 kJ/mol for both pathways; however, the dissociative pathway involves a high-energy precursor state with H in a 3-fold site under the Csbnd C bond undergoing reaction. An alternative decarboxylation pathway starting from Rsbnd CHsbnd COO leads to gas-phase CO2 and propylidene (in the absence of adsorbed H) or propyl (via insertion of adsorbed H) with energy barriers of 75 and 32 kJ/mol, respectively. The energy of the Rsbnd CHsbnd COO intermediate relative to gas-phase butanoic acid increases from 43 to 109 kJ/mol in the presence of adsorbed H, compensating for the lower decomposition barrier.

Lamb, H. Henry; Sremaniak, Laura; Whitten, Jerry L.

2013-01-01

377

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

378

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

379

Synthesis and theoretical calculations of carbazole substituted chalcone urea derivatives and studies their polyphenol oxidase enzyme activity.  

PubMed

Synthesis of carbazole substituted chalcone urea derivatives and their polyphenol oxidase enzyme activity effects on the diphenolase activity of banana tyrosinase were evaluated. Tyrosinase has been purified from banana on an affinity gel comprised of Sepharose 4B-L-tyrosine-p-aminobenzoic acid. The results showed that most of the compounds (3,4,5a,5d-h) inhibited and some of them (5c,5i-l) activated the tyrosinase enzyme activity. The molecular calculations were performed using Gaussian software for the synthesized compounds to explain the experimental results. PMID:22803668

Nixha, Arleta Rifati; Arslan, Mustafa; Atalay, Yusuf; Gençer, Nahit; Ergün, Adem; Arslan, Oktay

2013-08-01

380

Zinc(II) Complexes with Dangling Functional Organic Groups  

PubMed Central

Abstract Zinc(II) complexes with dangling functional organic groups were synthesized by reaction of zinc acetate with a series of bifunctional p-substituted benzene derivatives (a combination of carboxylate, oximate, amino, ?-ketoimine, and salicylaldime groups). Selective coordination to carboxylate groups was observed when the second functional group was an oxime or ?-ketoimine group. When the second group was an amine or salicylaldimine moiety, these groups were additionally coordinated. From the reaction with p-aminobenzoic acid, the compound [Zn2(OOCCH3)(OOC–C6H4–NH2)3]? was crystallized. It is a three-dimensional coordination polymer with bridging aminobenzoate ligands.

Yang, Jingxia; Puchberger, Michael; Qian, Renzhe; Maurer, Christian; Schubert, Ulrich

2012-01-01

381

Synthesis and bio-functionalization of multifunctional magnetic Fe3O4@Y2O3:Eu nanocomposites  

PubMed Central

A facile homogenous precipitation method has been developed for the synthesis of multifunctional, magnetic, luminescent nanocomposites with Fe3O4 nanoparticles as the core and europium-doped yttrium oxide (Y2O3: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.

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

2010-01-01

382

Flexible poly(amic acid) conducting polymers: effect of chemical composition on structural, electrochemical, and mechanical properties.  

PubMed

A new approach for creating flexible, mechanically strong poly(amic acid) (PAA) hybrid copolymers is described. The reduction of gold salts to gold nanoparticles by PAA coupled with its copolymerization in the presence of various silanes (e.g., N-[3-(trimethoxysilyl)-propyl] aniline (TMOSPA), 3-aminopropyl-trimethoxysilane (APTMOS), dichlorodimethylsilane (DCMS), and tetramethoxysilane (TMOS)) has enabled the design of a series of polymeric films. The resulting poly(amic acid), silane, and gold (PSG) solutions were employed for the fabrication of flexible, ternary polymers with a minimum bend ratio of 3 mm using thermal desolvation and/or wet-phase inversion techniques. By controlling the composition and synthesis conditions, porous PSG films were produced that are flexible or rigid, transparent or opaque, and/or mechanically strong. (1)H NMR, (13)C NMR, and Fourier transform infrared spectroscopy (FTIR) characterization results showed that the carboxylic acid moieties were retained in the PSG copolymer. Thermal stabilities with degradation characteristics of the polymers were determined using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Although structurally and morphologically different from the parent PAA, copolymerization with silanes had significantly improved the mechanical and interfacial property of the PSG class of films. PMID:20662482

Du, Nian; Wong, Cheuk; Feurstein, Michael; Sadik, Omowunmi A; Umbach, Christopher; Sammakia, Bahgat

2010-09-01

383

Synthesis of highly phosphonic acid functionalized benzene-bridged periodic mesoporous organosilicas for use as efficient dye adsorbents.  

PubMed

Periodic mesoporous organosilicas (PMOs) with benzene bridging groups in the silica wall were functionalized with a tunable content of phosphonic acid groups. These bifunctional materials were synthesized by co-condensation of two different organosilane precursors, that is, 1,4-bis(triethoxysilyl)benzene (BTEB) and sodium 3-(trihydroxysilyl)propyl methyl phosphate (SPMP), under acidic conditions using nonionic surfactant Brij-S10 as template. The materials exhibited well-ordered mesostructures and were characterized by X-ray diffraction, nitrogen sorption, TEM, TGA, FTIR, and solid-state NMR measurements. The materials thus obtained were employed as adsorbents to remove different types of dyes, for example, cationic dyes methylene blue and phenosafranine, anionic orange II, and amphoteric rhodamine B, from aqueous solutions. The materials exhibited a remarkably high adsorption capacity than activated carbon due to their ordered mesostructures, a large number of phosphonic acid groups, and high surface areas. The adsorption was mainly governed by electrostatic interaction, but also involved ?-? stacking interaction as well as hydrogen bonding. The adsorption kinetics can be better fitted by the pseudo-second order model. The adsorption process was controlled by the mechanisms of external mass transfer and intraparticle diffusion. The materials retained more than 97% dye removal efficiency after use for five consecutive cycles. PMID:25010459

Deka, Juti Rani; Liu, Chia-Ling; Wang, Tzu-Hua; Chang, Wei-Chieh; Kao, Hsien-Ming

2014-08-15

384

Boronic acid-functionalized core-shell-shell magnetic composite microspheres for the selective enrichment of glycoprotein.  

PubMed

In this work, core-shell-shell-structured boronic acid-functionalized magnetic composite microspheres Fe3O4@SiO2@poly (methyl methacrylate-co-4-vinylphenylbornoic acid) (Fe3O4@SiO2@P(MMA-co-VPBA)) with a uniform size and fine morphology were synthesized. Here, Fe3O4 magnetic particles were prepared by a solvothermal reaction, whereas the Fe3O4@SiO2 microspheres with a core-shell structure were obtained by a sol-gel process. 3-(Trimethoxysilyl) propyl methacrylate (MPS)-modified Fe3O4@SiO2 was used as the seed in the emulsion polymerization of MMA and VPBA to form the core-shell-shell-structured magnetic composite microspheres. As the boronic acid groups on the surface of Fe3O4@SiO2@P(MMA-co-VPBA) could form tight yet reversible covalent bonds with the cis-1,2-diols groups of glycoproteins, the magnetic composite microspheres were applied to enrich a standard glycoprotein, horseradish peroxidase (HRP), and the results demonstrated that the composite microspheres have a higher affinity for the glycoproteins in the presence of the nonglycoprotein bovine serum albumin (BSA) over HRP. Additionally, different monomer mole ratios of MMA/VPBA were studied, and the results implied that using MMA as the major monomer could reduce the amount of VPBA with a similar glycoprotein enrichment efficiency but a lower cost. PMID:23924282

Pan, Miaorong; Sun, Yangfei; Zheng, Jin; Yang, Wuli

2013-09-11

385

Automobiles and acid rain  

Microsoft Academic Search

In his editorial Acid rain Philip H. Abelson writes that everyone who drives an automobile is a contributor to acid rain. Examination of emissions data indicates that controlling automobile emissions will contribute little to solving acid precipitation problems. Of the strong acid anions associated with precipitation acidity, sulfate accounts for about 60% and nitrate for about 40%, on an equivalence

Hendrey

1985-01-01

386

Excitatory amino acid-induced phosphoinositide hydrolysis in Müller glia.  

PubMed

The presence of excitatory amino acid (EAA) receptors coupled to phosphoinositide metabolism in primary cultures of Müller (glial) cells from the chick retina was established. The order of potency of analogues for stimulating [3H]inositol phosphate (IP) accumulation was quisqualate (QA) > L-glutamate (L-Glu) = kainate (KA) > N-methyl-D-aspartate (NMDA) > L-aspartate (L-Asp) with EC50 in the range of 1-100 microM. 1-Aminocyclopentane-1,3-dicarboxylate (trans-ACPD), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), 2-amino-3-phosphonopropionate (AP3), and 2-amino-4-phosphonobutyrate (AP4) showed no effect either on basal concentration or on stimulated accumulation of [3H]IPs. The effect of EAA was potently inhibited by the ionotropic NMDA receptor antagonists 2-amino-5-phosphonopentanoate (AP5), 3-[(RS)-2-carboxy-piperazin-4-yl)]-propyl-1-phosphonate (CPP), and (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-10- imine (MK-801); L-Glu antagonists at non-NMDA receptors, the quinoxalines NBQX and DNQX, inhibited weakly the response to L-Glu, KA, and NMDA, and more potently that to QA. The translocation of protein kinase C was also stimulated by EAA with the same pharmacological profile, and was partially inhibited by kynurenate (KYN). L-Glu and KA induced 45Ca2+ influx, which was decreased by KYN and CNQX. EAA-induced [3H]IPs accumulation was decreased by verapamil but not by nifedipine, and slightly diminished by dantrolene. Results demonstrate that EAA-induced phosphoinositide hydrolysis in Müller cells shows pharmacological differences with that in astrocytes and neuronal cells and could be triggered by a different mechanism. PMID:7902338

López-Colomé, A M; Ortega, A; Romo-de-Vivar, M

1993-10-01

387

Folic Acid and Pregnancy  

MedlinePLUS

... before conception and during early pregnancy . About Folic Acid Folic acid, sometimes called folate, is a B ... well as tissue formation. Continue Getting Enough Folic Acid The Centers for Disease Control and Prevention (CDC) ...

388

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 ...

389

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 ... for testing. The most common reason for measuring uric acid levels is in the diagnosis or treatment of ...

390

Organic acids tunably catalyze carbonic Acid decomposition.  

PubMed

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

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

2014-07-10

391

Mono-/dihydroxybenzoic acid esters and phenol pyridinium derivatives as inhibitors of the mammalian carbonic anhydrase isoforms I, II, VII, IX, XII and XIV.  

PubMed

Using hydroxy-/dihydroxybenzoic acids as leads, a series of methyl, ethyl and iso-propyl esters of 4-hydroxy-benzoic acid, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5-dihydroxybenzoic acids and of coumaric acid, were obtained and investigated for the inhibition of six mammalian carbonic anhydrase (CA, EC 4.2.1.1) isoforms, that is, the cytosolic CA I, II and VII, and the transmembrane CA IX, XII and XIV, many of which are established drug targets. Other compounds incorporating phenol/catechol moieties were obtained from dopamine by reaction with fluorescein isothiocyanate or with 2,4,6-trisubstituted pyrylium salts. Some aminophenols were also derivatized in a similar manner, by using pyrylium salts. Many of these compounds showed increased inhibitory action compared to the lead compounds from which they were obtained, with efficacy in the submicromolar range against most investigated CA isoforms. As phenols are a class of less investigated CA inhibitors (CAIs) compared to the sulfonamides, and their mechanism of inhibition is less well understood, compounds of the type designed here may be helpful in gaining more insights into these phenomena. PMID:22668600

Carta, Fabrizio; Vullo, Daniela; Maresca, Alfonso; Scozzafava, Andrea; Supuran, Claudiu T

2013-03-15

392

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

393

Acid Rain Study Guide.  

ERIC Educational Resources Information Center

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

Hunger, Carolyn; And Others

394

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.

395

Improved synthesis of hyaluronic acid hydrogel and its effect on tissue augmentation.  

PubMed

HA-HMDA hydrogels were developed by direct amide bond formation between the carboxyl groups of hyaluronic acid (HA) and hexamethylenediamine (HMDA) with an optimized carboxyl group modification in the preliminary experiment. However, these HA-HMDA hydrogels transformed into an unstable liquid form after steam sterilization, and were problematic for application to actual dermal filler. A new method to overcome the problem of the previously developed HA-HMDA hydrogels is to prepare them by adjusting the pH in this study. Not only are these improved HA-HMDA hydrogels prepared with lower amounts of cross-linking and activation agents compared to the previously developed hydrogels, but they also maintain a stable form after steam sterilization. These improved HA-HMDA hydrogels showed higher viscoelasticity and longer lasting effects than the previous ones, despite the fact that the amount of the HMDA used as a cross-linking agent as well as 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC) and 1-hydroxybenzotriazole monohydrated (HOBt) used as activation agents were substantially reduced. According to an in vivo test using a wrinkled mouse model, the improved HA-HMDA hydrogels exhibited significantly improved tissue augmentation effects compared to a positive control of Restylane, which is widely used for the tissue augmentation throughout the world. Furthermore, histological analysis revealed excellent biocompatibility and safety of the improved synthesized HA-HMDA hydrogels. PMID:21527495

Yan, Xiang Mei; Seo, Moo Seok; Hwang, Eui Jin; Cho, Il Hwan; Hahn, Sei Kwang; Sohn, Uy Dong

2012-08-01

396

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

397

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

398

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

399

Determination of methylphenidate and its metabolite ritalinic acid in urine by liquid chromatography/tandem mass spectrometry.  

PubMed

Methylphenidate (MPH) is a drug that is licensed for treatment of ADHD and also narcolepsy. Monitoring of the parent drug and its major metabolite ritalinic acid (RA) in urine is considered necessary to ensure compliance with treatment programmes. A rapid, simple and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) assay was developed for the determination of MPH and its metabolite RA in human urine. After urine was diluted with water, methylphenidate, the major metabolite ritalinic acid, and d?-amphetamine as the internal standard were resolved on a PFP propyl column using gradient elution of 0.02% ammonium formate and acetonitrile. The total analysis time was 13.5 min. The three compounds were detected using electrospray ionisation in the positive mode. Standard curves were linear over the concentration range 5-5000 ?g/L (r>0.997), bias was ? ±20%, intra- and inter-day coefficients of variation (imprecision) were <8% and the limit of detection was 5 ?g/L. The limit of quantitation was set at 100 ?g/L. Matrix effects were up to 140% but these were accounted for by the internal standard. The assay is being used successfully in clinical practice to enhance the safe and effective use of methylphenidate. PMID:22204874

Paterson, Sharon M; Moore, Grant A; Florkowski, Chris M; George, Peter M

2012-01-15

400

Improved Cathode Interface Contact in Poly(3-hexylthiophene) and 1-(3-Methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 Based Organic Bulk Heterojunction Solar Cells by Introducing Compressive Stress  

NASA Astrophysics Data System (ADS)

The authors investigate the effects of compressive stress on the performance of organic solar cells based on poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) blends. The short-circuit current density is improved, and a maximum 16% enhancement in power conversion efficiency is achieved by introducing suitable a stress into the device. The improved performance is attributed to the formation of a good contact between the Al cathode and the P3HT:PCBM blend owing to the introduction of a suitable compressive stress. Meanwhile, the barrier height at Al/blend is lowered from 0.34 to 0.23 eV by evaluating the temperature dependence of the current--voltage characteristics.

Lou, Yanhui; Wang, Zhaokui; Naka, Shigeki; Okada, Hiroyuki

2012-07-01

401

PABA/NO as an anticancer lead: analogue synthesis, structure revision, solution chemistry, reactivity toward glutathione, and in vitro activity.  

PubMed

PABA/NO is a diazeniumdiolate of structure Me(2)NN(O)=NOAr (where Ar is a 5-substituted-2,4-dinitrophenyl ring whose 5-substituent is N-methyl-p-aminobenzoic acid). It has shown activity against human ovarian cancer xenografts in mice rivaling that of cisplatin, but it is poorly soluble and relatively unstable in water. Here we report structure-based optimization efforts resulting in three analogues with improved solubility and stability in aqueous solution. We sought to explain PABA/NO's physicochemical uniqueness among these four compounds, whose aminobenzoic acid precursors differ structurally only in the presence or absence of the N-methyl group and/or the position of the carboxyl moiety (meta or para). Studies revealed that PABA/NO's N-methyl-p-aminobenzoic acid substituent is bound to the dinitrobenzene ring via its carboxyl oxygen while the other three are linked through the aniline nitrogen. This constitutes a revision of the previously published PABA/NO structure. All four analogues reacted with GSH to produce bioactive nitric oxide (NO), but PABA/NO was the most reactive. Consistent with PABA/NO's potent suppression of A2780 human ovarian cancer xenograft growth in mice, it was the most potent of the four in the OVCAR-3 cell line. PMID:16451080

Saavedra, Joseph E; Srinivasan, Aloka; Buzard, Gregory S; Davies, Keith M; Waterhouse, David J; Inami, Keiko; Wilde, Thomas C; Citro, Michael L; Cuellar, Matthew; Deschamps, Jeffrey R; Parrish, Damon; Shami, Paul J; Findlay, Victoria J; Townsend, Danyelle M; Tew, Kenneth D; Singh, Shivendra; Jia, Lee; Ji, Xinhua; Keefer, Larry K

2006-02-01

402

Gas-phase Acidities of Aspartic Acid, Glutamic Acid, and their Amino Acid Amides.  

SciTech Connect

Gas-phase acidities (GA or ?Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage’s importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3–4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2? group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

Li, Zhong; Matus, Myrna H.; Velazquez, Hector A.; Dixon, David A.; Cassady, Carolyn J.

2007-02-14

403

Gas-phase acidities of aspartic acid, glutamic acid, and their amino acid amides  

NASA Astrophysics Data System (ADS)

Gas-phase acidities (GA or [Delta]Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage's importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3-4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

Li, Zhong; Matus, Myrna H.; Velazquez, Hector Adam; Dixon, David A.; Cassady, Carolyn J.

2007-09-01

404

Spectroscopic (FT-IR, FT-Raman) investigations and quantum chemical calculations of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-{3-[4-(3-methoxyphenyl)piperazin-1-yl]propyl}-4-azatricyclo[5.2.1.0(2,6)]dec-8-ene-3,5-dione.  

PubMed

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-{3-[4-(3-methoxyphenyl) piperazin-1-yl]propyl}-4-azatricyclo[5.2.1.0(2,6)]dec-8-ene-3,5-dione have been investigated experimentally and theoretically using Gaussian09 software package. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. Gauge-including atomic orbital (1)H NMR chemical shifts calculations were carried out and compared with experimental data. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular Electrostatic Potential was performed by the DFT method and the infrared and Raman intensities have also been reported. First hyperpolarizability is calculated in order to find its role in non-liner optics. The calculated geometrical parameters (SDD) are in agreement with that of similar derivatives. Mulliken's net charges have been calculated and compared with the atomic natural charges. PMID:24747931

Renjith, R; Sheena Mary, Y; Yohannan Panicker, C; Varghese, Hema Tresa; Pakosi?ska-Parys, Magdalena; Van Alsenoy, C; Al-Saadi, Abdulaziz A

2014-08-14

405

Spectroscopic (FT-IR, FT-Raman) investigations and quantum chemical calculations of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-{3-[4-(3-methoxyphenyl)piperazin-1-yl]propyl}-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione  

NASA Astrophysics Data System (ADS)

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-{3-[4-(3-methoxyphenyl) piperazin-1-yl]propyl}-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione have been investigated experimentally and theoretically using Gaussian09 software package. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. Gauge-including atomic orbital 1H NMR chemical shifts calculations were carried out and compared with experimental data. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular Electrostatic Potential was performed by the DFT method and the infrared and Raman intensities have also been reported. First hyperpolarizability is calculated in order to find its role in non-liner optics. The calculated geometrical parameters (SDD) are in agreement with that of similar derivatives. Mulliken’s net charges have been calculated and compared with the atomic natural charges.

Renjith, R.; Mary, Y. Sheena; Panicker, C. Yohannan; Varghese, Hema Tresa; Pakosi?ska-Parys, Magdalena; Van Alsenoy, C.; Al-Saadi, Abdulaziz A.

2014-08-01

406

Biological evaluation and structure-activity relationships of bis-(3-aryl-3-oxo-propyl)-methylamine hydrochlorides and 4-aryl-3-arylcarbonyl-1-methyl-4-piperidinol hydrochlorides as potential cytotoxic agents and their alkylating ability towards cellular glutathione in human leukemic T cells.  

PubMed

Various bis (3-aryl-3-oxo-propyl)methylamine hydrochlorides 1 and their corresponding structural and non-classical isomers 4-aryl-3-arylcarbonyl-1-methyl-4-piperidinols 3 were evaluated against human leukemic T (Jurkat) cells and found to possess significant cytotoxicity. Among the series 1 (bis-Mannich bases) and 3 (corresponding piperidinols), compounds la, 1c and 1e showed cytotoxic potency which was approximately 1.6, 3.7 and 3.4 times that of the reference drug 5-fluorouracil, respectively. Except for compound 1d, conversion of bis-Mannich bases to their corresponding piperidinols 3a, 3b and 3e lowered the potency. Besides chloro derivative 1d, bis-Mannich bases displayed greater cytotoxicity compared with their mono-Mannich bases, series 5. Representative bis-Mannich bases (1a, 1e) and piperidinols (3a, 3e) decreased the glutathione level of Jurkat cells. Molecular modeling was utilized in order to evaluate whether the shape, size, critical volume, solvent accessible area and partition coefficient of the different compounds had contributed to the varying potencies observed. Bis-Mannich bases 1a, 1c and 1e may serve as candidate anticancer agents for future development. PMID:16032973

Gul, Mustafa; Gul, Halise Inci; Das, Umashankar; Hanninen, Osmo

2005-01-01

407

Modulating the acidity: highly acidic Brønsted acids in asymmetric catalysis.  

PubMed

Recently, chiral highly acidic Brønsted acids have emerged as powerful catalysts for enantioselective C-C and C-X bond-forming reactions. Their strong acidity renders them valuable tools for the activation of imines, carbonyl compounds, and other weakly basic substrates. As a result, new perspectives are opened and highly stereoselective transformations based on the concept of chiral contact-ion-pair catalysis can be realized. This Minireview gives an overview of the design and application of these new organocatalysts and presents recent results in this rapidly growing field. PMID:21678531

Rueping, Magnus; Nachtsheim, Boris J; Ieawsuwan, Winai; Atodiresei, Iuliana

2011-07-18

408

Thin-Layer Separation of Citric Acid Cycle Intermediates, Lactic Acid, and the Amino Acid Taurine.  

National Technical Information Service (NTIS)

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 ...

R. T. Riley M. C. Mix

1979-01-01

409

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.

410

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

411

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 %).

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

412

Succinic Acid in Wines.  

National Technical Information Service (NTIS)

Following a brief discussion of methods which are currently employed to determine the succinic acid content of wines, as well as the shortcomings of those methods, procedures used for colorimetric evaluation of this particular acid are explained. The prin...

M. Castino

1969-01-01

413

Omega-3 fatty acids  

PubMed Central

OBJECTIVE To examine evidence for the role of omega-3 fatty acids in cardiovascular disease. QUALITY OF EVIDENCE PubMed was searched for articles on the role of omega-3 fatty acids in cardiovascular disease. Level I and II evidence indicates that omega-3 fatty acids are beneficial in improving cardiovascular outcomes. MAIN MESSAGE Dietary intake of omega-3 fatty acids has declined by 80% during the last 100 years, while intake of omega-6 fatty acids has greatly increased. Omega-3 fatty acids are cardioprotective mainly due to beneficial effects on arrhythmias, atherosclerosis, inflammation, and thrombosis. There is also evidence that they improve endothelial function, lower blood pressure, and significantly lower triglycerides. CONCLUSION There is good evidence in the literature that increasing intake of omega-3 fatty acids improves cardiac outcomes. Physicians need to integrate dietary recommendations for consumption of omega-3 fatty acids into their usual cardiovascular care.

Schwalfenberg, Gerry

2006-01-01

414

Acid Aerosols Issue Paper.  

National Technical Information Service (NTIS)

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...

1988-01-01

415

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

416

Polymerization of Itaconic Acid.  

National Technical Information Service (NTIS)

Itaconic acid has various uses in chain copolymerization reactions, because of its two carboxylic groups and relatively good reactivity with different comonomers. As an unsaturated dicarboxylic acid it also has applications in grafting reactions and polyc...

J. Ahlgren

1990-01-01

417

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 ...

418

Folic Acid Quiz  

MedlinePLUS

... folic acid supplement d) eat a cup of broccoli 5. Spina bifida and anencephaly: Hint a) are ... acid every day. This question is tricky because broccoli is a natural source of food folate, however ...

419

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 ...

420

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 ...

421

Facts about Folic Acid  

MedlinePLUS

... of the baby's brain and spine ( anencephaly and spina bifida ). How much folic acid a woman needs 400 ... audiocast about folic acid. Related Pages Healthy Pregnancy spina bifida Birth Defects CDC’s National Center on Birth Defects ...

422

Uric acid - blood  

MedlinePLUS

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

423

Plasma amino acids  

MedlinePLUS

Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Rheumatoid arthritis High or low concentrations of individual plasma amino acids must be interpreted along with other ...

424

Versatile peroxidase of Bjerkandera fumosa: substrate and inhibitor specificity.  

PubMed

The inhibitor and substrate specificities of versatile peroxidase from Bjerkandera fumosa (VPBF) were studied. Two different effects were found: NaN(3), Tween-80, anthracene, and fluorene decreased the activity of VPBF, but p-aminobenzoic acid increased it. A mixed mechanism of effector influence on the activity of this enzyme was shown. The catalytic properties of VPBF in the oxidation of mono- and polycyclic aromatic compounds were studied also. 2,7-Diaminofluorene, ABTS, veratryl alcohol, and syringaldazine can be oxidized by VPBF in two ways: either directly by the enzyme or by diffusible chelated Mn(3+) as an oxidizing agent. During VPBF oxidation of 2,7-diaminofluorene, both with and without Mn(2+), biphasic kinetics with apparent saturation in both micromolar and millimolar ranges were obtained. In the case of ABTS, inhibition of VPBF activity by an excess of substrate was observed. Direct oxidation of p-aminobenzoic acid by versatile peroxidase was found for the first time. The oxidation of three- and four-ring PAHs by VPBF was investigated, and the oxidation of anthracene, phenanthrene, fluorene, pyrene, chrysene, and fluoranthene was shown. The products of PAH oxidation (9,10-anthraquinone, 9,10-phenanthrenequinone, and 9-fluorenone) catalyzed by VPBF were identified. PMID:23199738

Pozdnyakova, Natalia; Makarov, Oleg; Chernyshova, Marina; Turkovskaya, Olga; Jarosz-Wilkolazka, Anna

2013-01-10

425

Development and validation of a gradient reversed-phase high-performance liquid chromatographic assay for S(-)-2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin (N-0923) from a transdermal delivery system.  

PubMed

A gradient reversed-phase HPLC method for potency determination of N-0923 (10 mg) from a transdermal delivery system (TDS), was developed and validated with single point calibration using internal standard quantitation. N-0923 and the internal standard, N-0434, are eluted from a reversed-phase C18 column using a gradient which contains 0.1 M triethylamine-0.04 M citrate buffer, pH 5.9, water, and acetonitrile with UV detection at 272 nm. N-0923 is isolated from the transdermal delivery system by extraction with n-heptane followed by extraction of the resulting organic phase with 0.1 M citric acid containing the internal standard. The method was free from matrix interferences in both untreated and forced degraded placebo delivery systems. Acceptable linearity and quantitative recovery from spiked placebo delivery systems over the range 50-150% of nominal label claim were demonstrated. Within-day assay precision from individual samples of active transdermal delivery systems (n = 10) was 5.6% R.S.D. The detection limit was at least 0.1 microgram/ml which is equivalent to 0.05% of the working standard concentration. Replicate injection precision at this level was 0.08% R.S.D. (n = 4). Analysis of thermally stressed active and placebo delivery systems with this HPLC method and photodiode-array detection showed that the chromatography was stability-indicating as demonstrated by the absence of measurable interferences from principal degradation products of either the n-0923 or the delivery system excipients. PMID:8548020

Walters, D L; Strong, C R; Green, S V; Curtis, M A

1995-08-18

426

Refining Lurgi tar acids  

SciTech Connect

There is disclosed a process for removing tar bases and neutral oils from the Lurgi tar acids by treating the tar acids with aqueous sodium bisulfate to change the tar bases to salts and to hydrolyze the neutral oils to hydrolysis products and distilling the tar acids to obtain refined tar acid as the distillate while the tar base salts and neutral oil hydrolysis products remain as residue.

Greco, N.P.

1984-04-17

427

Nucleic acid molecule  

US Patent & Trademark Office Database

The invention relates to an isolated nucleic acid molecule encoding a polypeptide capable of producing a triterpenoid hydrocarbon. The invention also relates to the encoded polypeptide, a vector comprising the nucleic acid molecule, a recombinant non-human organism comprising the nucleic acid molecule, and to methods of producing a triterpenoid hydrocarbon or an intermediate of biofuel using the nucleic acid molecule, polypeptide or recombinant organism.

2011-10-11

428

Linolenic acid deficiency  

Microsoft Academic Search

Linolenic acid deficiency has not been demonstrated clearly in warm blooded animals, yet circumstantial evidence suggests\\u000a that n?3 fatty acids may have functions in these animals. The fact that several species of fish definitely require dietary\\u000a n?3 fatty acids indicates that n?3 fatty acids have important and specific functions in these animals and suggests that such\\u000a functions may also be

J. Tinoco; R. Babcock; I. Hincenbergs; B. Medwadowski; P. Miljanich; M. A. Williams

1979-01-01

429

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

430

Acid-fast stain  

MedlinePLUS

... The slide is then washed with an acid solution and a different stain is applied. Bacteria that hold onto the first dye are considered "acid-fast" because they resist the acid wash. This type of bacteria is associated with tuberculosis and other infections.

431

[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

432

Energy and acid rain  

Microsoft Academic Search

Acid rain is one of the foremost environmental issues of the 1980s and will be of continuining importance to energy policy for several reasons. First, the pollutants that cause acid rain are projected to increase through the end of the century as the demand for energy grows and as coal replaces oil. Second, many of the effects of acid rain

R R Gould

1984-01-01

433

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

434

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."

Kessler, James H.; Galvan, Patricia M.

2007-01-01

435

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

436

Crystallization of uric acid  

NASA Astrophysics Data System (ADS)

Crystals of uric acid have been grown in tetra methoxy silane and silica gel medium. Small winged, transparent, platy crystals of uric acid of about 0.5x0.5x0.1 mm were grown and were found to be hydrated uric acid.

Kalkura, S. Narayana; Vaidyan, V. K.; Kanakavel, M.; Ramasamy, P.

1993-09-01

437

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

2008-08-05

438

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

439

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

440

Acid Rain: Students Site  

NSDL National Science Digital Library

This website introduces students to the concepts and issues surrounding acid rain. They will learn what acid rain is, how it forms, and what its effects are on humans, on the environment (lakes, rivers), and on infrastructure (buildings, monuments). There is also discussion of what is being done to reduce the presence of acid rain, and some suggestions for the students themselves to help reduce acid rain. A set of games, puzzles, and activities provides students with an opportunity to put their new knowledge of acid rain to use, and an animated slide show is provided to visually illustrate its causes and effects. A Spanish translation is available.

441

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

442

Amino acid analysis  

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

443

Demospongic Acids Revisited  

PubMed Central

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

Kornprobst, Jean-Michel; Barnathan, Gilles

2010-01-01

444

[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

445

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

446

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

447

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

PubMed

Microorganisms are capable of producing a wide variety of biopolymers. Homopoly(amino acid)s and homooligo(amin