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1

21 CFR 172.165 - Quaternary ammonium chloride combination.  

Code of Federal Regulations, 2013 CFR

...FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.165 Quaternary ammonium chloride combination. The food additive, quaternary ammonium chloride...

2013-04-01

2

Efficient cellulose solvent: quaternary ammonium chlorides.  

PubMed

Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry. PMID:24014114

Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

2013-09-09

3

Algicidal Activity of a Surface-Bonded Organosilicon Quaternary Ammonium Chloride  

PubMed Central

The hydrolysis product of a quaternary amine-containing organosilicon salt, 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride, was found to exhibit algicidal activity while chemically bonded to a variety of substrates. Six representative species of Chlorophyta, Cyanophyta, and Chrysophyta were used to evaluate the algicidal activity. Substrate-bonded 14C-labeled organosilicon quaternary ammonium salt when attached to nonwoven fibers was durable to repeated washings, and algicidal activity could not be attributed to slow release of the chemical. Images

Walters, P. A.; Abbott, E. A.; Isquith, A. J.

1973-01-01

4

Reaction of hydrogen chloride with halides of quaternary ammonium salts  

Microsoft Academic Search

1.The solubility of (n-C4H9)4NCl and (n-C4H9)4NBr in benzene was determined at 25°.2.The interaction of gaseous HCl with tetra-substituted ammonium halides was investigated. A decrease in the dimensions of the anion and an increase in the dimensions of the cation promote interaction.3.The behavior of the reaction products of HCl with tetra-substituted ammonium halides in benzene was investigated. In the case of

N. M. Aplatova; Yu. M. Kessler; A. I. Gorbanev

1964-01-01

5

Effects of saccharin and quaternary ammonium chlorides on the electrodeposition of nickel from a Watts-type electrolyte  

Microsoft Academic Search

The effect of the presence of quaternary ammonium chlorides (QACl) and saccharin on various electrodeposition parameters for nickel deposition on a stainless steel cathode from a Watts-type plating bath was investigated. The parameters included cathodic current efficiency, throwing power of the bath, cathodic polarization, crystal orientation, and quality of the deposit. The following additives were investigated: saccharin, 1-alkyloxymethyl 3-benzyl imidazolium

Aleksander Ciszewski; Szymon Posluszny; Grzegorz Milczarek; Marek Baraniak

2004-01-01

6

Chemical Warfare Agent Decontaminant Solution Using Quaternary Ammonium Complexes.  

National Technical Information Service (NTIS)

A chemical warfare agent decontamination solution made up of about 20% of a quaternary ammonium complex containing benzyltrimethylammonium chloride and benzyltriethylammonium chloride and about 20% by weight of an oxidizer, dissolved in a solvent, such as...

D. T. Crounce

1997-01-01

7

40 CFR 721.10154 - Quaternary ammonium compounds, dicoco alkyldimethyl, chlorides, reaction products with silica.  

Code of Federal Regulations, 2013 CFR

...Uses for Specific Chemical Substances § 721...alkyldimethyl, chlorides, reaction products with silica. (a) Chemical substance and significant...reporting . (1) The chemical substance identified...alkyldimethyl, chlorides, reaction products...

2013-07-01

8

The toxicity of the quaternary ammonium compound benzalkonium chloride alone and in mixtures with other anionic compounds to bacteria in test systems with Vibrio fischeri and Pseudomonas putida.  

PubMed

Mixtures of chemicals are present in the aquatic environment but standard testing methods assess only single compounds. One aspect of this question is the importance of the formation of ionic pairs, for example from quaternary ammonium compounds with organic anions, and the significance of the ionic pairs for bacterial toxicity in the aquatic environment. The aim of the present study was to investigate the toxicity of the cationic quaternary ammonium compound benzalkonium chloride (BAC) against aquatic bacteria in the presence of substances commonly found in wastewater, such as the anionic surfactant linear alkylbenzene sulfonate (LAS), naphthalene sulfonic acid (NSA), sodium dodecylsulfonate (SDS), and benzene sulfonic acid (BSA). The growth inhibition test with Pseudomonas putida and the Vibrio fischeri luminescent inhibition test were used to determine the toxicity of single compounds and compound mixtures. The results found in this study indicate that ion pair formation is of minor significance under the test conditions applied here. PMID:18272223

Sütterlin, H; Alexy, R; Kümmerer, K

2008-02-12

9

Antifungal activity of gemini quaternary ammonium salts.  

PubMed

A series of gemini quaternary ammonium chlorides and bromides with various alkyl chain and spacer lengths was synthesized. The most active compounds against fungi were chlorides with 10 carbon atoms within the hydrophobic chain. Among these compounds were few with no hemolytic activity at minimal inhibitory concentrations. None of the tested compounds were cytotoxic and mutagenic. Cationic gemini surfactants poorly reduced the adhesion of microorganisms to the polystyrene plate, but inhibited the filamentation of Candida albicans. One of the tested compounds eradicated C. albicans and Rodotorula mucilaginosa biofilm, what could be important in overcoming catheter-associated infections. It was also shown that gemini surfactants enhanced the sensitivity of C. albicans to azoles and polyenes, thus they might be potentially used in combined therapy against fungi. PMID:23827647

Ob??k, Ewa; Piecuch, Agata; Krasowska, Anna; Luczy?ski, Jacek

2013-07-01

10

A Toxicological Evaluation of Certain Heparin-Quaternary Ammonium Complexes.  

National Technical Information Service (NTIS)

Physical and chemical characterizations show that the heparin-quaternary ammonium salt complexes can be reproducibly prepared from a given lot of a quaternary ammonium salt. Local toxicity studies also indicate that both the tridodecyl methyl ammonium chl...

G. A. Grode J. P. Crowley R. D. Falb R. I. Leininger

1974-01-01

11

The toxicity of the quaternary ammonium compound benzalkonium chloride alone and in mixtures with other anionic compounds to bacteria in test systems with Vibrio fischeri and Pseudomonas putida  

Microsoft Academic Search

Mixtures of chemicals are present in the aquatic environment but standard testing methods assess only single compounds. One aspect of this question is the importance of the formation of ionic pairs, for example from quaternary ammonium compounds with organic anions, and the significance of the ionic pairs for bacterial toxicity in the aquatic environment. The aim of the present study

H. Sütterlin; R. Alexy; K. Kümmerer

2008-01-01

12

Bacterial metabolism of quaternary ammonium compounds.  

PubMed Central

Of 10 quaternary ammonium compounds tested for biodegradation by the biological oxygen demand technique, only decyl- and hexadecyltrimethylammonium bromides were decomposed by organisms derived from sewage and soil. A mixture consisting of individual strains of Pseudomonas and Xanthomonas grew in solutions containing decyltrimethylammonium bromide as sole carbon source. The xanthomonad metabolized this quaternary ammonium compound in the presence of other organic molecules. The products of this activity included 9-carboxynomyl- and 7-carboxyheptyltrimethylammonium, suggesting that the terminal carbon of the decyl moiety is oxidized and the resulting carboxylic acid is subject to beta-oxidation.

Dean-Raymond, D; Alexander, M

1977-01-01

13

Low Sensitivity of Listeria monocytogenes to Quaternary Ammonium Compounds  

Microsoft Academic Search

Ninety-seven epidemiologically unrelated strains of Listeria monocytogenes were investigated for their sen- sitivities to quaternary ammonium compounds (benzalkonium chloride and cetrimide). The MICs for seven serogroup 1\\/2 strains were high. Three came from the environment and four came from food; none were isolated from human or animal samples. All 97 strains carried the mdrL gene, which encodes a multidrug efflux

L. Mereghetti; R. Quentin; N. Marquet-Van Der Mee; A. Audurier

2000-01-01

14

‘Biting effect’ stabilizing gallate-type catechin\\/quaternary ammonium ion complexes  

Microsoft Academic Search

The relationship between the structure of catechins and their binding ability for quaternary ammonium ions was examined. From binding studies using eight catechins and benzyltrimethylammonium chloride, it was revealed that the binding ability of the gallate-type catechins is much higher than that of the non-gallate-type catechins. The quaternary ammonium ion binding site of the gallate-type catechins was determined to be

Nobuyuki Hayashi; Tomomi Ujihara

2007-01-01

15

Effect of alkyl quaternary ammonium on processing discoloration of melt-intercalated PVC-montmorillonite composites  

Microsoft Academic Search

The effects of alkyl quaternary ammonium on the processing thermal stability of poly (vinyl chloride)\\/alkyl quaternary ammonium modified montmorillonite (PVC\\/OMMT) composites were investigated. PVC\\/sodium montmorillonite (MMT) composites were prepared for comparison. The intercalated PVC\\/OMMT composites exhibited a non-terminal rheological behavior, and showed better mechanical properties and higher thermal degradation stability than the PVC\\/MMT composites. However, under identical melt processing conditions,

Chaoying Wan; Yong Zhang; Yinxi Zhang

2004-01-01

16

Microtitration of various anions with quaternary ammonium halides using solid-state electrodes  

Microsoft Academic Search

Many solid-state electrodes were found to respond as endpoint detectors in the potentiometric titration of large inorganic and organic anions with quaternary ammonium halides. The best response was obtained with the iodide and cyanide electrodes although practically any electrode can function as endpoint sensor. The titrants were hexadecylpyridinium chloride and hexadecyltrimethylammonium chloride; hexadecyltrimethylammonium bromide and Hyamine 1622 may also be

W SELIG

1980-01-01

17

Incidence of Class 1 Integrons in a Quaternary Ammonium Compound-Polluted Environment  

Microsoft Academic Search

Samples of effluent and soil were collected from a reed bed system used to remediate liquid waste from a wool finishing mill with a high use of quaternary ammonium compounds (QACs) and were compared with samples of agricultural soils. Resistance quotients of aerobic gram-negative and gram-positive bacteria to ditallowdi- methylammomium chloride (DTDMAC) and cetyltrimethylammonium bromide (CTAB) were established by plating

W. H. Gaze; N. Abdouslam; P. M. Hawkey; E. M. H. Wellington

2005-01-01

18

On inhibition of hydrogen-sulfide corrosion of steels with quaternary ammonium salts  

Microsoft Academic Search

The corrosion and electrochemical behavior of carbon steels in standard 0.5% chloride electrolytes acidified with CH3COOH and saturated with H2S was studied. The possibility of protecting steels with quaternary ammonium salts (QASs) obtained by reactions of secondary and tertiary amines with benzyl chloride was investigated. It was found that the protective\\u000a properties of QASs depend on their chemical structures and

Yu. I. Kuznetsov; L. V. Frolova; E. V. Tomina

2006-01-01

19

Fusion Properties of Some Ionic Quaternary Ammonium Compounds.  

National Technical Information Service (NTIS)

Enthalpy, entropy and molar volume changes during the fusion process of a wide range of quaternary ammonium compounds are presented. This group of compounds has hitherto been unexplored and is of interest since, as far as melting mechanisms are concerned,...

T. G. Coker J. Ambrose G. J. Janz

1970-01-01

20

21 CFR 184.1138 - Ammonium chloride.  

Code of Federal Regulations, 2013 CFR

...Ammonium chloride is crystallized from the solution. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 20, which is incorporated by reference. Copies are available from the National Academy Press,...

2013-04-01

21

Ineffectiveness of a quaternary ammonium salt and povidone-iodine for the inactivation of Ascaris suum eggs.  

PubMed

Two commonly used disinfectants, a quaternary ammonium salt and povidone-iodine, were tested for effectiveness against unembryonated Ascaris suum eggs. The quaternary ammonium salt (alkyl dimethyl benzyl ammonium chloride) had no effect on the Ascaris eggs (10 minutes and 22°C) when compared with the controls in water with egg viabilities of 88.8% ± 3.3% and 86.9% ± 6.2%, respectively. An additional quaternary ammonium salt, 2.5% benzethonium chloride, also had no effect. Phenol (5%) and cresol (3%) completely inactivated the eggs. Povidone-iodine at 100%, 50%, 10%, and 1% had no effect on the eggs at exposures of 5, 15, 30, 60, or 120 minutes (22°C) compared with the water controls. PMID:23102984

Labare, Michael P; Soohoo, Hilary; Kim, Dong; Tsoi, Key yan; Liotta, Janice L; Bowman, Dwight D

2012-10-24

22

Polycationic antimicrobial dendrimers: a comparison of alkyl pyridinium,quaternary ammonium, quaternary phosphonium and tertiary sulfonium salts  

NASA Astrophysics Data System (ADS)

Polycationic biocides usually kill bacteria through the interactions of the positively charged head groups with negatively charged bacteria and the interactions of the hydrophobic segments with phospholipid cell membranes, which implies that high local charge densities and a large number of hydrophobic groups would lead to enhanced biocidal potency. The advent of dendrimers offers us the first-ever opportunity to achieve the desired high local density. We have demonstrated that dimethyl dodecyl ammonium chloride functionalized polypropylene imine dendrimers are over 100 times more potent than their small molecule ounterparts. In this study, quaternary ammonium, quaternary phosphonium, alkyl pyridinium and tertiary sulfonium salts based on polypropylene imine dendrimers have been synthesized and characterized. Their antimicrobial properties have been quantified with a novel bioluminescence method. The structure-activity relationship of these polycationic dendrimers has also been investigated to elucidate the molecular mechanism for the enhanced antimicrobial effects.

Chen, Chris; Cooper, Stuart

2000-03-01

23

Tyrosine urea muscarinic acetylcholine receptor antagonists: achiral quaternary ammonium groups.  

PubMed

Tyrosine ureas had been identified as potent muscarinic receptor antagonists with promising in vivo activity. Controlling the stereochemistry of the chiral quaternary ammonium center had proved to be a serious issue for this series, however. Herein we describe the preparation and SAR of tyrosine urea antagonists containing achiral quaternary ammonium centers. The most successful such moiety was the 2-methylimidazo[2,1-b][1,3]thiazol-7-ium group which yielded highly potent antagonists with long duration of action in an inhaled animal model of bronchoconstriction. PMID:23099092

Jin, Qi; Davis, Roderick S; Bullion, Ann M; Jin, Jian; Wang, Yonghui; Widdowson, Katherine L; Palovich, Michael R; Foley, James J; Schmidt, Dulcie B; Buckley, Peter T; Webb, Edward F; Salmon, Michael; Belmonte, Kristen E; Sarau, Henry M; Busch-Petersen, Jakob

2012-10-02

24

Lab simulation of profile modification and enhanced oil recovery with a quaternary ammonium cationic polymer  

Microsoft Academic Search

Long-term water flooding in oilfield exploitation generally results in a marked increase of interlayer and\\/or inner-layer heterogeneity of oil reservoirs and premature polymer production in large quantities from flooding reservoirs. This paper presents a novel quaternary ammonium cationic polymer (NCP), which was prepared by using maize starch and (2,3-epoxypropyl)trimethylammonium chloride as raw materials. The effect of NCP on water plugging

Ru Qiao; Rui Zhang; Weiqun Zhu; Peijun Gong

25

Conductometric determination of quaternary ammonium salts by sodium perchlorate and vice versa  

Microsoft Academic Search

A conductometric method is proposed for the determination of quaternary ammonium salts (chloride or bromide), based on the\\u000a poor solubility of the relative perchlorates. A comparison between expected and found values shows that the method is suitable,\\u000a rapid, and easy for quantities in the range from 0.2 to 5 g. The error depends on the solubility of the relative perchlorate.

E. Bottari; P. De Felice; M. R. Festa

1998-01-01

26

Resistance to quaternary ammonium compounds in food-related bacteria.  

PubMed

Microbial resistance to antimicrobial agents continues to be a major problem. The frequent use and misuse of disinfectants based on quaternary ammonium compounds (QACs) in food-processing industries have imposed a selective pressure and may contribute to the emergence of disinfectant-resistant microorganisms. A total number of 1,325 Gram-negative isolates (Escherichia coli, other coliforms Vibrio spp., and Aeromonas spp.) and 500 Enterococcus spp. from food and food-processing industries and fish farming were screened for natural resistance to the QAC-based disinfectant benzalkonium chloride (BC). Of the 1,825 isolates, 16 strains, mainly from meat retail shops, showed low-level resistance to BC. None of the Enterococcus spp. from broiler, cattle, and pigs, the antibiotic-resistant E. coli from pig intestine and fish pathogens Vibrio spp. and Aeromonas spp. from the Norwegian fish farming industry were resistant to BC. The BC-resistant strains were examined for susceptibility to 15 different antibiotics, disinfectants, and dyes. No systematic cross-resistance between BC and any of the other antimicrobial agents tested was detected. Stable enhanced resistance in Enterobacter cloacae isolates was demonstrated by step-wise adaptation in increasing concentrations of BC. In conclusion, BC resistance among food-associated Gram-negative bacteria and Enterococcus spp. is not frequent, but resistance may develop to user concentrations after exposure to sublethal concentrations of BC. PMID:12523638

Sidhu, Maan Singh; Sørum, Henning; Holck, Askild

2002-01-01

27

Studies of corrosion inhibitors for zinc–manganese batteries: quinoline quaternary ammonium phenolates  

Microsoft Academic Search

Three compounds, hydroxyethyl quinoline quaternary ammonium phenolate, hydroxyethyl quinoline quaternary ammonium para-methyl phenolate and hydroxyethyl quinoline quaternary ammonium para-nitro phenolate were synthesized and tested as corrosion inhibitors for zinc–manganese batteries. Such quaternary ammonium salts derived from heterocylic molecule containing N atoms possess a higher density electron cloud around the functional groups and provide a larger projective area. From the analysis

Dongshe Zhang; Lidong Li; Lixin Cao; Neifen Yang; Chubao Huang

2001-01-01

28

Bacterial resistance to disinfectants containing quaternary ammonium compounds  

Microsoft Academic Search

Quaternary ammonium compounds (QAC) are widely used as disinfectants in both medical and food environments. Microbial contaminants are, therefore, regularly exposed to their action and the isolation from clinical and food sources of resistant bacteria continues to be reported in many countries. Resistance to QAC in clinical strains of staphylococci is encoded by one of at least three resistance genes,

G. Sundheim; S. Langsrud; E. Heir; A. L. Holck

1998-01-01

29

Supernormal optical characteristics in doped quaternary ammonium salt KDP crystals  

Microsoft Academic Search

Potassium dihydrogen phosphate, KH2PO4 (KDP) crystals with different concentrations of quaternary ammonium salt in solution were grown. In this paper, unusual transmittance ratio properties of KDP are reported. The transmittance ratio is smaller than unity at some locations. These results indicate that the plane wave effect and optical activity are highly displaced in KDP crystals, and the effect is varies

Xin-guang Xu; Xun Sun; Zheng-ping Wang; Gui-bao Xu; Zong-shu Shao; Zhang-shou Gao

2003-01-01

30

Quaternary ammonium sulfanilamide: a membrane-impermeant carbonic anhydrase inhibitor  

Microsoft Academic Search

A novel carbonic anhydrase (CA) inhibitor, quaternary ammonium sulfanilamide (QAS), was tested for potency as a CA inhibitor and for its ability to be excluded from permeating biological membranes. Inhibitor titration plots of QAS vs. pure bovine CA II and CA from the gills of the blue crab, Callinectes sapidus, yielded K\\/sub i\\/ values of approx. 15 ..mu..M; thus QAS

1987-01-01

31

Soft antimicrobial agents: synthesis and activity of labile environmentally friendly long chain quaternary ammonium compounds.  

PubMed

A series of soft quaternary ammonium antimicrobial agents, which are analogues to currently used quaternary ammonium preservatives such as cetyl pyridinium chloride and benzalkonium chloride, were synthesized. These soft analogues consist of long alkyl chain connected to a polar headgroup via chemically labile spacer group. They are characterized by facile nonenzymatic and enzymatic degradation to form their original nontoxic building blocks. However, their chemical stability has to be adequate in order for them to have antimicrobial effects. Stability studies and antibacterial and antiviral activity measurements revealed relationship between activity, lipophilicity, and stability. Their minimum inhibitory concentration (MIC) was as low as 1 microg/mL, and their viral reduction was in some cases greater than 6.7 log. The structure-activity studies demonstrate that the bioactive compounds (i.e., MIC for Gram-positive bacteria of <10 microg/mL) have an alkyl chain length between 12 and 18 carbon atoms, with a polar headgroup preferably of a small quaternary ammonium group, and their acquired inactivation half-life must be greater than 3 h at 60 degrees C. PMID:12954069

Thorsteinsson, Thorsteinn; Másson, Már; Kristinsson, Karl G; Hjálmarsdóttir, Martha A; Hilmarsson, Hilmar; Loftsson, Thorsteinn

2003-09-11

32

SOLVENT EXTRACTION ENHANCED MICROFILTRATION OF STRONTIUM AND TECHNETIUM WITH DI2-ETHYLHEXYLPHOSPHORIC ACID AND QUATERNARY AMMONIUM SALTS  

Microsoft Academic Search

Application of extractants in form of microphase (micelles or microdrops) separated from aqueous matrix by microfiltration, “solvent extraction enhanced microfiltration (SEEMF)” is closely related to micellar enhanced ultrafiltration (MEUF) technique.Uptake of strontium from aqueous solutions with microphase di-2-ethylhexylphosphoric acid (DEHPA) and pertechnetate with quaternary ammoniumsalts (QAS): trioctylmethylammonium chloride, benzyldodecyl-dimethylammonium bromide, and n-(?-carbethoxypenthadecyl)trimetyl-ammonium chloride was investigated as a function of microphase

F. Macášek; A. Danihlik

1998-01-01

33

Comparative catalytic activity of quaternary ammonium salts in synthesis of dialkyl sulfides under conditions of phase-transfer catalysis  

SciTech Connect

It was shown that quaternary ammonium salts obtained from the C/sub 7/-C/sub 9/ fraction of technical trialkylamines may be used as phase-transfer catalysts in synthesis of dialkyl sulfides. The catalytic activities of methyltrialkylammonium chloride and methyl sulfate are virtually equal, and both are inferior to methyltrialkylammonium sulfate. Methyltrialkylammonium (MTAAC), trialkylbenzyl (TABAC), and triethylbenzylammonium (TEBAC) chlorides form the following series in order of catalytic activity: MTAAC > TABAC >> TEBAC.

Vasilevskaya, T.N.; Grineva, N.I.; Chernousova, G.A.; Gartsman, A.N.; Andrievskii, V.N.; Pershina, A.I.; Kravchenko, L.K.; Trotsenko, Z.P.; Myakina, N.I.; Kotylarevskii, I.L.

1987-07-10

34

Titration of long-chain quaternary ammonium compounds using tetraphenylboron  

Microsoft Academic Search

A rapid macro procedure for the determination of long-chain quaternary ammonium compounds (QAC) has been developed using sodium\\u000a tetraphenylboron as a titrant. About 1–1.5 meq of QAC is dissolved or dispersed in 50 ml of water. Dichlorofluorescein is\\u000a added as an indicator. The sample is then titrated with 0.06 N aqueous sodium tetraphenylboron. As long as free QAC is present

L. D. Metcalfe; R. J. Martin; A. A. Schmitz

1966-01-01

35

Assay of quaternary ammonium antimicrobial compounds by aqueous potentiometric titration  

Microsoft Academic Search

An automatic potentiometric titration method for the determination of quaternary ammonium antimicrobial compounds at the macro\\u000a level is described. The procedure involves the use of standard sodium lauryl sulfate as the titrant and a nitrate ion-selective\\u000a or surfactant electrode to detect the end point. The method, which includes a new, simpler means of titrant standardization,\\u000a avoids the use of hazardous

George T. Battaglini

2002-01-01

36

40 CFR 721.8658 - Modified polymer of vinyl acetate and quaternary ammonium compound (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Modified polymer of vinyl acetate and quaternary ammonium...Chemical Substances § 721.8658 Modified polymer of vinyl acetate and quaternary ammonium...substance identified generically as modified polymer of vinyl acetate and quaternary...

2013-07-01

37

Evaluation of the cytotoxic effects of bis-quaternary ammonium antimicrobial reagents on human cells  

Microsoft Academic Search

The cytotoxic effects of newly synthesized bis-quaternary ammonium compounds (bis-QACs) and benzalkonium chloride were investigated on skin and blood cells, namely normal human epidermal keratinocytes of neonatal foreskin, a normal human skin fibroblast cell line NB1RGB, erythrocytes and a lymphoma cell line JM. The bis-QACs tested were 4,4?-(1,6-hexamethylenedithio)bis(1-octylpyridinium iodide) (4DTBP-6,8), N,N?-tetramethylenebis(1-dodecyl-4-carbamoylpyridinium iodide) (4BCAP-4,12), N,N?-hexamethylenebis(1-decyl-4-carbamoylpyridinium iodide) (4BCAP-6,10), 4,4?-(1,4-tetramethylenedicarbonyldiamine) bis (1-decylpyridinium iodide)

H Nagamune; T Maeda; K Ohkura; K Yamamoto; M Nakajima; H Kourai

2000-01-01

38

Synthesis, Characterization and Surface-Activity of a Polyoxyethylene Ether Trimeric Quaternary Ammonium Surfactant  

Microsoft Academic Search

A trimeric quaternary ammonium salt surfactant containing polyoxyethylene chains was synthesized from fatty alcohol polyoxyethylene\\u000a ether, pentamethyldiethylenetriamine and thionyl chloride by a two-step process. Its chemical structure was characterized,\\u000a and the surface activity in aqueous solution was studied at different temperatures. The results showed that when the concentration\\u000a attains the CMC (1.0 mmol\\/L), the surface tension is 38.9 mN m?1 and

Jiaoxia Zhang; Yaping Zheng; Peiying Yu; Lin He; Huining Wang; Rumin Wang

2010-01-01

39

Interaction of quaternary ammonium and phosphonium salts with photosynthetic membranes.  

PubMed

Distinct concentration ranges of selected quaternary ammonium and phosphonium salts were elaborated to induce stimulatory or inhibitory effects, respectively, on photosynthetic reactions. By means of fluorescence induction measurements 3 different effects of alkylbenzyldimethylammonium chloride (ABDAC; zephirol) in chloroplast preparations from Pisum sativum were observed. 60 microM ABDAC produced a strong increase in Fmax with concurrently improved Kautsky kinetics. Increased ABDAC concentration (500 microM) led to a strong fluorescence quenching - virtually indistinguishable from the conditions following the addition of photosystem II electron acceptors like K3Fe[CN]6. Further increase of ABDAC to 5 mM provoked a drastic increase in the fluorescence yield together with the complete loss of any detectable kinetics. We suggest a 3-step interaction of ABDAC with the thylakoid membranes of photosynthetic organisms similar to our earlier discussion (Bader and Höper (1993), Z. Naturforsch. 49c, 87-94). We examined a series of derivatives with selectively modified side chains, central atoms and counter ions, respectively. Both an alkyl chain of the type ([-CH2-]n; n approximately > 10) and effective polar components are indispensable for the adsorption and intercalation of the molecule onto and into the thylakoid membranes. The benzyl group could be replaced by a methyl residue without any loss of effectiveness; replacement of the central nitrogen (N) by phosphorus (P) and the counter ion Cl by Br did not modify the effects and the results were indistinguishable from the ABDAC effect proper. Shortening of the alkyl chain to (-CH2-)6 resulted in a less effective interaction of e.g. tetraoctylammonium bromide with the photosynthetic membrane. Flash-induced oxygen evolution measurements with selected derivatives (15 microm) substantiated our interpretation of an improved OEC functioning by a substantial lowering of the miss parameter a and the exclusion of a chemical reduction as the standard S-state distribution was not affected. As evidenced by both SDS-PAGE and Western blot analyses the investigated molecules showed a direct interaction. The polypeptide patterns were characterized by a severe shift of the molecular weight components from high (20-67 kDa) to low (< 20 kDa) values. PMID:11837658

Spiegel, S; Bader, K P

40

Thermal properties of quaternary ammonium and pyridinium compounds  

SciTech Connect

In the present work an attempt was made at a comprehensive investigation of the influence of the chemical structure of a whole series of cation-active surfactants on the stability to temperature influences, and the general directions of the irreversible transformations at high temperature were established. As a result of a study of processes of thermal decomposition of quaternary ammonium and syridinium salts, quantitative correlations were established according to the influence of the chemical structure of the salts on the limits of thermal stability. On the basis of a detailed analysis of volatile pyrolysis products, concrete schemes of the conversions in the objects studied were proposed.

Aksenova, V.P.; Khar'kov, S.N.; Logovotovskaya, V.D.; Belotserkovets, N.I.; Chegolya, A.S.

1982-12-10

41

Controlled stripping of polyelectrolyte multilayers by quaternary ammonium surfactants.  

PubMed

The quartz crystal microbalance with dissipation technique (QCM-D) and atomic force microscopy (AFM) have been employed to study the interaction of N-tetradecyl trimethyl ammonium bromide (TdTmAB) with polyelectrolyte multilayers containing poly(sodium 4-styrene sulfonate) (PSS) as the polyanion and either poly(allylamine hydrochloride) (PAH) or poly(diallyl dimethyl ammonium chloride) (PDADMAC) as the polycations. The multilayers were exposed to aqueous solutions of TdTmAB. This resulted in a selective removal of PDADMAC PSS layers while layers with PAH as polycation remained stable. It is suggested that PDADMAC/PSS multilayers can be employed as strippable protecting layers. PMID:21638450

Iturri Ramos, Jagoba Jon; Llarena, Irantzu; Fernández, Luis; Moya, Sergio Enrique; Donath, Edwin

2009-10-19

42

Chemiluminescence enhancement of 1,2-di[3,4,5-tri(3,4,5-trihydroxybenzoyloxy)benzoyloxy] benzene in the presence of quaternary ammonium ions.  

PubMed

The chemiluminescence intensity of 1,2-di[3,4,5-tri(3,4,5-trihydroxybenzoyloxy)benzoyloxy] benzene increased in the presence of quaternary ammonium ions, such as acetylcholine chloride, choline chloride or benzyltrimethylammonium chloride. The complex of 1,2-di[3,4,5-tri(3,4,5-trihydroxybenzoyloxy)benzoyloxy] benzene with acetylcholine chloride, choline chloride or benzyltrimethylammonium chloride was investigated by (1)H-NMR spectroscopy. The structure of the complex formed from 1,2-di[3,4,5-tri(3,4,5-trihydroxybenzoyloxy)benzoyloxy] benzene with choline chloride was described by an ab initio quantum chemical calculation. PMID:19630093

Nakazono, Manabu; Agawa, Hiroki; Nanbu, Shinkoh; Zaitsu, Kiyoshi

43

Dissolution kinetics of smithsonite ore in ammonium chloride solution  

Microsoft Academic Search

The results of a dissolution kinetics study of smithsonite ore in ammonium chloride are presented. Effect of stirring speed, ore particle size, reaction temperature, and the concentration of ammonium chloride on zinc dissolution rate are determined. The results obtained show that leaching of about 91.2% of zinc is achieved using 84–110 ?m ore particle size at a reaction temperature of

Shaohua Ju; Tang Motang; Yang Shenghai; Li Yingnian

2005-01-01

44

40 CFR 415.240 - Applicability; description of the ammonium chloride production subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the ammonium chloride production subcategory. 415.240...MANUFACTURING POINT SOURCE CATEGORY Ammonium Chloride Production Subcategory § 415.240 Applicability; description of the ammonium chloride production subcategory. The...

2010-07-01

45

40 CFR 415.240 - Applicability; description of the ammonium chloride production subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the ammonium chloride production subcategory. 415.240...MANUFACTURING POINT SOURCE CATEGORY Ammonium Chloride Production Subcategory § 415.240 Applicability; description of the ammonium chloride production subcategory. The...

2009-07-01

46

Tetracalcium phosphate composite containing quaternary ammonium dimethacrylate with antibacterial properties.  

PubMed

Tooth caries is a carbohydrate-modified bacterial infectious disease, and recurrent caries is a frequent reason for restoration failure. The objective of this study was to develop a novel antibacterial composite using tetracalcium phosphate (TTCP) fillers and bis(2-methacryloyloxy-ethyl) dimethyl-ammonium bromide, which is a quaternary ammonium dimethacrylate (QADM). QADM was synthesized using 2-(N,N-dimethylamino)ethyl methacrylate and 2-bromoethyl methacrylate and incorporated into a resin. The resin was filled with 40% TTCP and 30% glass particles. The following QADM mass fractions in the composite were tested: 0%, 6%, 12%, and 18%. Streptococcus mutans biofilms were formed on the composites and the colony-forming units (CFUs), metabolic activity, and lactic acid production were measured. The TTCP-QADM composite had flexural strength and elastic modulus similar to those of two commercial composites (p > 0.1). Increasing the QADM content in TTCP composite greatly decreased the bacteria growth and biofilm matrix production. There were significantly more dead bacteria with increasing QADM content. TTCP composite containing 18% QADM had biofilm CFU, metabolic activity, and acid production about half of those without QADM. Inversely linear relationships were established between QADM mass fraction and S. mutans biofilm CFU, metabolic activity, and acid production, with correlation coefficients R(2) ? 0.98. In conclusion, TTCP-QADM composites were developed and the effect of QADM mass fraction on the antibacterial properties of the composite was determined for the first time. The novel TTCP-QADM composites possessing a strong antibacterial capability, together with calcium phosphate ion release and good mechanical properties, are promising for dental restorations to reduce biofilm growth and recurrent caries. PMID:22190356

Cheng, Lei; Weir, Michael D; Limkangwalmongkol, Penwadee; Hack, Gary D; Xu, Hockin H K; Chen, Qianming; Zhou, Xuedong

2011-12-21

47

Tetracalcium phosphate composite containing quaternary ammonium dimethacrylate with antibacterial properties  

PubMed Central

Tooth caries is a carbohydrate-modified bacterial infectious disease, and recurrent caries is a frequent reason for restoration failure. The objective of this study was to develop a novel antibacterial composite using tetracalcium phosphate (TTCP) fillers and bis(2-methacryloyloxy-ethyl) dimethyl-ammonium bromide, which is a quaternary ammonium dimethacrylate (QADM). QADM was synthesized using 2-(N,N-dimethylamino)ethyl methacrylate and 2-bromoethyl methacrylate and incorporated into a resin. The resin was filled with 40% TTCP and 30% glass particles. The following QADM mass fractions in the composite were tested: 0%, 6%, 12%, and 18%. Streptococcus mutans biofilms were formed on the composites and the colony-forming units (CFUs), metabolic activity, and lactic acid production were measured. The TTCP-QADM composite had flexural strength and elastic modulus similar to those of two commercial composites (p > 0.1). Increasing the QADM content in TTCP composite greatly decreased the bacteria growth and biofilm matrix production. There were significantly more dead bacteria with increasing QADM content. TTCP composite containing 18% QADM had biofilm CFU, metabolic activity, and acid production about half of those without QADM. Inversely linear relationships were established between QADM mass fraction and S. mutans biofilm CFU, metabolic activity, and acid production, with correlation coefficients R2 ? 0.98. In conclusion, TTCP-QADM composites were developed and the effect of QADM mass fraction on the antibacterial properties of the composite was determined for the first time. The novel TTCP-QADM composites possessing a strong antibacterial capability, together with calcium phosphate ion release and good mechanical properties, are promising for dental restorations to reduce biofilm growth and recurrent caries.

Cheng, Lei; Weir, Michael D.; Limkangwalmongkol, Penwadee; Hack, Gary D.; Xu, Hockin H. K.; Chen, Qianming; Zhou, Xuedong

2012-01-01

48

Bactericidal and Sporicidal Activity of a Quaternary Ammonium Resin-Triiodide Complex  

PubMed Central

Tests to determine the potential use of a quaternary ammonium resin-triiodide complex as a sterilizing agent showed that it was an ineffective sporicide and that bactericidal activity was impaired by complex milieu.

Gilmour, Marion N.; Wicksell, Eva K.

1972-01-01

49

Induction of contact dermatitis in guinea pigs by quaternary ammonium compounds: the mechanism of antigen formation.  

PubMed Central

Eight quaternary ammonium compounds were tested for their ability to induce contact dermatitis in guinea pigs by using a modified Freund's complete adjuvant test together with the guinea pig maximization test. Only two quaternary ammonium salts of the eight tested could be designated as strong allergens. These two active substances were shown to be capable of stable association with membrane lipids in forming immunogenic complexes. This surface complexation phenomenon was confirmed by using a spin-labeled quaternary ammonium salt which competed for binding sites at the surface of epidermal cells in vivo. Electron spin resonance was used to demonstrate that stable "ion-pairs" are formed between binding sites and the two allergenic preservatives. Furthermore, information was obtained on the kinetics of immunogenic complex formation as well as on the position and orientation of the quaternary ammonium ion at the cell surface.

Schallreuter, K U; Schulz, K H; Wood, J M

1986-01-01

50

Electrochemical properties of quaternary ammonium salts for electrochemical capacitors  

SciTech Connect

The limiting reduction and oxidation potentials and electrolytic conductivities of new quaternary ammonium salts were examined for electrochemical capacitor applications, whose anions have already been tested as lithium salts for lithium battery applications. The anodic stability was in the following order BR{sub 4}{sup {minus}} < ClO{sub 4}{sup {minus}} {le} CF{sub 3}SO{sub 3}{sup {minus}} < (CF{sub 3}SO{sub 2}){sub 2}N{sup {minus}} {le} C{sub 4}F{sub 9}SO{sub 3}{sup {minus}} < BF{sub 4}{sup {minus}} < PF{sub 6}{sup {minus}} {le} AsF{sub 6}{sup {minus}} < SbF{sub 6}{sup {minus}}. The electrolytic conductivities of Me{sub 4{minus}n}Et{sub n}N(CF{sub 3}SO{sub 2}){sub 2}N (n = 0--4) were examined in comparison with Me{sub 4{minus}n}Et{sub n}NBF{sub 4} counterparts. These imide salts showed good solubility, relatively high conductivity, and anodic stability in propylene carbonate. Et{sub 4}N(CF{sub 3}SO{sub 2}){sub 2}N was found to be a good supporting salt for low permittivity organic solvents, and it afforded a highly conductive electrolyte system based on the ethylene carbonate-dimethyl carbonate mixed solvent, which is useful for electrochemical capacitor applications.

Ue, Makoto; Takeda, Masayuki; Takehara, Masahiro; Mori, Shoichiro [Mitsubishi Chemical Corp., Inashiki, Ibaraki (Japan). Tsukuba Research Center

1997-08-01

51

Cellular uptake of polyurethane nanocarriers mediated by gemini quaternary ammonium.  

PubMed

The effective passage of drug formulations into tumor cells is a key factor in the development of nanoscale delivery systems. However, rapid cellular uptake with reduced toxicity remains a great challenge for efficient and safe delivery. In this study, we first use gemini quaternary ammonium (GQA) as a cell internalization promoter to enhance the cellular uptake of drug nanocarriers. It is found that a twenty times faster cell internalization could be achieved by introducing GQA into biodegradable multiblock polyurethane nanomicelles, as confirmed by flow cytometry and confocal laser scanning microscopy (CLSM) studies. Meanwhile, an added methoxyl-poly(ethylene glycol) (mPEG) outer corona could protect these cationic micelles from cytotoxicity at high concentrations, as verified by methyl tetrazolium (MTT) assay. Moreover, GQA not only acts as an enhancer for rapid cellular entry, but also plays an important role in controlled self-assembly and high drug loading capacity. Our work offers a new understanding on the role of cationic surfactants; and provides a facile and economical approach for the design of versatile drug nanocarriers to achieve efficient delivery and good biocompatibility. PMID:21907404

Ding, Mingming; He, Xueling; Wang, Zhigao; Li, Jiehua; Tan, Hong; Deng, Hua; Fu, Qiang; Gu, Qun

2011-09-09

52

Antibacterial nanocomposite with calcium phosphate and quaternary ammonium.  

PubMed

Secondary caries is a frequent reason for restoration failure, resulting from acidogenic bacteria and their biofilms. The objectives of this study were to: (1) develop a novel nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP) and quaternary ammonium dimethacrylate (QADM); and (2) investigate its mechanical and antibacterial durability. A spray-drying technique yielded NACP with particle size of 116 nm. The nanocomposite contained NACP and reinforcement glass fillers, with QADM in the resin. Two commercial composites were tested as controls. Composites were inoculated with Streptococcus mutans. After 180-day water-aging, NACP+QADM nanocomposite had flexural strength and elastic modulus matching those of commercial controls (p > 0.1). NACP+QADM nanocomposite reduced the biofilm colony-forming units (CFU) by 3-fold, compared with commercial composites (p < 0.05). Metabolic activity and lactic acid production of biofilms on NACP+QADM were much less than those on commercial composites (p < 0.05). The antibacterial properties of NACP+QADM were maintained after water-aging for 30, 90, and 180 d (p > 0.05). In conclusion, the novel NACP-QADM nanocomposite greatly decreased biofilm metabolic activity, CFU, and lactic acid, while matching the load-bearing capability of commercial composites without antibacterial properties. The NACP-QADM nanocomposite with strong and durable antibacterial properties, together with its previously reported Ca-PO(4) release capability, may render it useful for caries-inhibiting restorations. PMID:22403412

Cheng, L; Weir, M D; Zhang, K; Xu, S M; Chen, Q; Zhou, X; Xu, H H K

2012-03-08

53

Quaternary ammonium sulfanilamide: a membrane-impermeant carbonic anhydrase inhibitor  

SciTech Connect

A novel carbonic anhydrase (CA) inhibitor, quaternary ammonium sulfanilamide (QAS), was tested for potency as a CA inhibitor and for its ability to be excluded from permeating biological membranes. Inhibitor titration plots of QAS vs. pure bovine CA II and CA from the gills of the blue crab, Callinectes sapidus, yielded K/sub i/ values of approx. 15 ..mu..M; thus QAS is a relatively weak but effective CA inhibitor. Permeability of the QAS was directly tested by two independent methods. The inhibitor was excluded from human erythrocytes incubated in 5 mM QAS for 24 h as determined using an /sup 18/O-labeled mass spectrometer CA assay for intact cells. Also QAS injected into the hemolymph of C. sapidus (1 or 10 mM) did not cross the basal membrane of the gill. The compound was cleared from the hemolymph by 96 h after injection, and at no time during that period could the QAS be detected in homogenates of gill tissue. Total branchial CA activity was only slightly reduced following the QAS injection. These data indicate that QAS is a CA inhibitor to which biological membranes are impermeable and that can be used in vivo and in vitro in the study of membrane-associated CA.

Henry, R.P.

1987-05-01

54

Synthesis and aggregation behavior of a hexameric quaternary ammonium surfactant.  

PubMed

A star-shaped hexameric quaternary ammonium surfactant (PAHB), bearing six hydrophobic chains and six charged hydrophilic headgroups connected by an amide-type spacer group, was synthesized. The self-assembly behavior of the surfactant in aqueous solution was studied by surface tension, electrical conductivity, isothermal titration microcalorimetry, dynamic light scattering, cryogenic transmission electron microscopy, and NMR techniques. The results reveal that there are two critical aggregate concentrations during the process of aggregation, namely C(1) and C(2). The aggregate transitions are proved to be caused by the changes of the surfactant configuration through hydrophobic interaction among the hydrocarbon chains. Below C(1), PAHB may present a star-shaped molecular configuration due to intramolecular electrostatic repulsion among the charged headgroups, and large aggregates with network-like structure are observed. Between C(1) and C(2), the hydrophobic interaction among the hydrophobic chains may become stronger to make the hydrophobic chains of the PAHB molecules curve back and pack more closely, and then the network-like aggregates transfer to large spherical aggregates of ?100 nm. Beyond C(2), the hydrophobic interaction may become strong enough to cause the PAHB molecular configuration to turn into a pyramid-like shape, resulting in the transition of the spherical large aggregates to spherical micelles of ?10 nm. Interestingly, the PAHB displays high emulsification ability to linear fatty alkyls even at very low concentration. PMID:21797217

Fan, Yaxun; Hou, Yanbo; Xiang, Junfeng; Yu, Defeng; Wu, Chunxian; Tian, Maozhang; Han, Yuchun; Wang, Yilin

2011-08-09

55

Mixed Micellization of Anionic Ammonium Dodecyl Sulfate and Cationic Octadecyl Trimethyl Ammonium Chloride  

Microsoft Academic Search

In aqueous mixtures of cationic OTAC (octadecyl trimethyl ammonium chloride) and anionic ADS (ammonium dodecyl sulfate) surfactants, mixed micelles were formed at low (< 0.2 wt %) total surfactant concentrations. For these mixtures mixed micellization and interaction of surfactant molecules were examined. Mixed critical micelle concentration (CMC), thermodynamic potentials of micellization, and minimum area per surfactant molecule at the interface

Kye-Hong Kang; Hong-Un Kim; Kyung-Hee Lim; Noh-Hee Jeong

56

40 CFR 415.240 - Applicability; description of the ammonium chloride production subcategory.  

Code of Federal Regulations, 2012 CFR

...CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Ammonium Chloride Production...discharges resulting from the production of ammonium chloride by the reaction of anhydrous ammonia with hydrogen chloride gas and by...

2012-07-01

57

Preparation of anhydrous magnesium chloride from ammonium magnesium chloride hexahydrate  

Microsoft Academic Search

Magnesium chloride hydrate can be dehydrated to some extent by heating. However, it is not possible to fully dehydrate magnesium chloride by heating in air because of hydrolytic decomposition. Accordingly, the dehydration should be carried out in hydrogen chloride gas atmosphere. However, this process causes many problems, including HCl gas storage and corrosive nature, consuming a large amount of HCl

Hyoung-Choon Eom; Ho-Sung Yoon

2010-01-01

58

Fate and effect of monoalkyl quaternary ammonium surfactants in the aquatic environment  

Microsoft Academic Search

The effect of the alkyl chain of quaternary ammonium-based surfactants on their aquatic toxicity and aerobic biodegradability has been studied. Two families of monoalkylquats surfactants were selected: alkyl trimethyl ammonium and alkyl benzyl dimethyl ammonium halides. Acute toxicity tests on Daphnia magna and Photobacterium phosphoreum were carried out and EC50 values in the range of 0.1–1 mg\\/l were obtained for

M. T Garc??a; I Ribosa; T Guindulain; J Sánchez-Leal; J Vives-Rego

2001-01-01

59

Influence of quaternary ammonium compounds on the microbial reductive dechlorination of pentachloroaniline.  

PubMed

The inhibitory effect of two widely used quaternary ammonium compounds (QACs) - alkyl benzyl dimethyl (AB) and hexadecyl trimethyl (HD) ammonium chloride - on fermentation, methanogenesis and pentachloroaniline (PCA) dechlorination was assessed using a mixed, methanogenic, PCA-dechlorinating culture amended with AB or HD at a concentration range from 5 to 70 ?M. PCA dechlorination was inhibited at 5 ?M AB and was completely inhibited at 25 or 5 ?M by AB or HD, respectively. However, the PCA dechlorination pathway was the same in both the QACs-free and QACs-amended culture series. Fermentation (acidogenesis) and methanogenesis were inhibited by both AB and HD at and above 25 ?M but to a lesser degree than PCA dechlorination. Overall, HD resulted in a more severe inhibition of the mixed culture than AB. Adsorption of both QACs to the mixed culture biomass followed the Freundlich isotherm model. The adsorption affinity of HD for the mixed culture biomass was significantly higher than that of AB, which may be related to the observed higher inhibitory effects of HD compared to AB. Both AB and HD were not degraded in the mixed, dechlorinating culture used in this study. PMID:24075473

Hong, Jinglan; Tezel, Ulas; Okutman Tas, Didem; Pavlostathis, Spyros G

2013-09-15

60

A complicated hospitalization following dilute ammonium chloride ingestion  

Microsoft Academic Search

Introduction  Unintentional ingestions of dilute (<7.5%) cleaning solutions containing ammonium chloride typically do not cause serious\\u000a harm. We present a case of an intentional ingestion of a dilute ammonium chloride solution resulting in significant morbidity.\\u000a \\u000a \\u000a \\u000a Case Report  A 60-year-old woman with bipolar disorder presented one hour after an intentional ingestion of approximately 15 fluid ounces\\u000a (500 mL) of an algae and odor

Kendra Hammond; Tiffany Graybill; Susannah E. Spiess; Jenny Lu; Jerrold B. Leikin

2009-01-01

61

Environmental risk assessment for quaternary ammonium compounds: a case study from Austria.  

PubMed

Quaternary ammonium compounds (QAC) are widely used as disinfectants, biocides, and detergents, among a variety of other applications. The cationic surface-activity of QAC determines their potential to act as a biocide on both target and non-target organisms. This study aims to provide a broad-based environmental risk characterization and evaluation for selected QAC with particular focus on the situation in Austrian rivers. A modular study design was employed involving environmental exposure characterization, QAC fate and effect analysis in wastewater, ecotoxicological effect characterization, and environmental risk evaluation. A wide array of Austrian surface waters and wastewater effluents were screened for the selected key compounds, benzalkonium chlorides and dialkyldimethylammonium chlorides with different C-chain lengths. Ecotoxicological effect characterization was based on both microbiotests for a set of representative aquatic organisms and a literature review. For risk evaluation, the PEC/PNEC ratio was above 1 for some rivers. Notably, small rivers with a high particulate matter were contaminated with QAC in the case of high water incidents. Hence, for the Austrian sites studied, a QAC-derived risk to sensitive aquatic non-target organisms could not be excluded. PMID:17302311

Grillitsch, B; Gans, O; Kreuzinger, N; Scharf, S; Uhl, M; Fuerhacker, M

2006-01-01

62

Copper and Quaternary Ammonium Cations Exert Synergistic Bactericidal and Antibiofilm Activity against Pseudomonas aeruginosa?  

PubMed Central

Biofilms are slimy aggregates of microbes that are likely responsible for many chronic infections as well as for contamination of clinical and industrial environments. Pseudomonas aeruginosa is a prevalent hospital pathogen that is well known for its ability to form biofilms that are recalcitrant to many different antimicrobial treatments. We have devised a high-throughput method for testing combinations of antimicrobials for synergistic activity against biofilms, including those formed by P. aeruginosa. This approach was used to look for changes in biofilm susceptibility to various biocides when these agents were combined with metal ions. This process identified that Cu2+ works synergistically with quaternary ammonium compounds (QACs; specifically benzalkonium chloride, cetalkonium chloride, cetylpyridinium chloride, myristalkonium chloride, and Polycide) to kill P. aeruginosa biofilms. In some cases, adding Cu2+ to QACs resulted in a 128-fold decrease in the biofilm minimum bactericidal concentration compared to that for single-agent treatments. In combination, these agents retained broad-spectrum antimicrobial activity that also eradicated biofilms of Escherichia coli, Staphylococcus aureus, Salmonella enterica serovar Cholerasuis, and Pseudomonas fluorescens. To investigate the mechanism of action, isothermal titration calorimetry was used to show that Cu2+ and QACs do not interact in aqueous solutions, suggesting that each agent exerts microbiological toxicity through independent biochemical routes. Additionally, Cu2+ and QACs, both alone and in combination, reduced the activity of nitrate reductases, which are enzymes that are important for normal biofilm growth. Collectively, the results of this study indicate that Cu2+ and QACs are effective combinations of antimicrobials that may be used to kill bacterial biofilms.

Harrison, Joe J.; Turner, Raymond J.; Joo, Daniel A.; Stan, Michelle A.; Chan, Catherine S.; Allan, Nick D.; Vrionis, Helen A.; Olson, Merle E.; Ceri, Howard

2008-01-01

63

Trospium chloride: an update on a quaternary anticholinergic for treatment of urge urinary incontinence  

PubMed Central

Trospium chloride is a quaternary ammonium compound, which is a competitive antagonist at muscarinic cholinergic receptors. Preclinical studies using porcine and human detrusor muscle strips demonstrated that trospium chloride was many-fold more potent than oxybutynin and tolterodine in inhibiting contractile responses to carbachol and electrical stimulation. The drug is poorly bioavailable orally (< 10%) and food reduces absorption by 70%– 80%. It is predominantly eliminated renally as unchanged compound. Trospium chloride, dosed 20 mg twice daily, is significantly superior to placebo in improving cystometric parameters, reducing urinary frequency, reducing incontinence episodes, and increasing urine volume per micturition. In active-controlled trials, trospium chloride was at least equivalent to immediate-release formulations of oxybutynin and tolterodine in efficacy and tolerability. The most problematic adverse effects of trospium chloride are the anticholinergic effects of dry mouth and constipation. Comparative efficacy/tolerability data with long-acting formulations of oxybutynin and tolterodine as well as other anticholinergics such as solifenacin and darifenacin are not available. On the basis of available data, trospium chloride does not appear to be a substantial advance upon existing anticholinergics in the management of urge urinary incontinence.

Guay, David RP

2005-01-01

64

Raman and far ir spectroscopic study of quaternary ammonium polybromide fused salt phases for zinc bromine circulating electrolyte batteries  

SciTech Connect

The circulating electrolyte zinc bromine battery is an attractive advanced battery system. The electrolyte is a solution of zinc bromide, quaternary ammonium bromides for bromine complexation and added salts to enhance properties. Laser Raman spectroscopy and far infrared spectroscopy were used to characterize the liquid quaternary ammonium polybromide fused salt phases.

Larrabee, J.A.; Graf, K.R.; Grimes, P.G.

1985-01-01

65

Superhydrophobic cotton fabric coating based on a complex layer of silica nanoparticles and perfluorooctylated quaternary ammonium silane coupling agent  

Microsoft Academic Search

A superhydrophobic complex coating for cotton fabrics based on silica nanoparticles and perfluorooctylated quaternary ammonium silane coupling agent (PFSC) was reported in this article. The complex thin film was prepared through a sol–gel process using cotton fabrics as a substrate. Silica nanoparticles in the coating made the textile surface much rougher, and perfluorooctylated quaternary ammonium silane coupling agent on the

Minghua Yu; Guotuan Gu; Wei-Dong Meng; Feng-Ling Qing

2007-01-01

66

Toxic and Sublethal Effects of Ammonium Chloride on a Freshwater Fish Oreochromis mossambicus  

Microsoft Academic Search

The effects of ammonium chloride on survival and feeding energetics of the freshwater fish Oreochromis mossambicus were studied. At a concentration of 600 mg L-1 ammonium chloride, 100% mortality was observed within 24 h; no mortality occurred at 400 mg L-1 within 96 h; Concentration of 450 mg L-1 ammonium chloride was found as median lethal concentration at 96 h

E. Felista Rani; M. Elumalai; M. P. Balasubramanian

1998-01-01

67

Adsorption and Adsolubilization by Monomeric, Dimeric, or Trimeric Quaternary Ammonium Surfactant at Silica\\/Water Interface  

Microsoft Academic Search

Adsorption of monomeric, dimeric, or trimeric quaternary ammonium surfactant on silica from its aqueous solution has been investigated by measuring adsorption density, ? potential, and dispersion stability. The monomeric (dodecyltrimethylammonium bromide, 1RQ), dimeric (1,2-bis(dodecyldimethylammonio)ethane dibromide, 2RenQ), and trimeric (methyldodecylbis[2-dimethyldodecylammonio) ethyl] ammonium tribromide, 3RdienQ) surfactants are used in this study. The amounts adsorbed at saturation decrease with increasing dodecyl chain number

Kunio Esumi; Masaya Goino; Yoshifumi Koide

1996-01-01

68

Preparation, Surface-Active Properties and Antimicrobial Activities of Bis(Ester Quaternary Ammonium) Salts  

Microsoft Academic Search

New cationic surfactants, bis-quaternary ammonium salts, were prepared from N,N-dimethylaminoalkyl esters of saturated fatty acids and products of the reactions of epichlorohydrin with primary amines:\\u000a pentyl-, hexyl- and octylamine. The bis (ester–ammonium) salts obtained were examined in respect to their surface-active properties:\\u000a critical micelle concentration (CMC), effectiveness of surface tension reduction (?CMC), and adsorption efficiency (pC20). All these surfactants showed

Joanna W?grzy?ska; Jan Chlebicki; Irena Maliszewska

2007-01-01

69

Dual Action Antimicrobials: Nitric Oxide Release from Quaternary Ammonium-Functionalized Silica Nanoparticles  

PubMed Central

The synthesis of quaternary ammonium (QA)-functionalized silica nanoparticles with and without nitric oxide (NO) release capabilities is described. Glycidyltrialkylammonium chlorides of varied alkyl chain lengths (i.e., methyl, butyl, octyl, and dodecyl) were tethered to the surface of amine-containing silica nanoparticles via a ring-opening reaction. Secondary amines throughout the particle were then functionalized with N-diazeniumdiolates NO donors to yield dual functional nanomaterials with surface QAs and total NO payloads of ca. 0.3 ?mol/mg. The bactericidal activities of singly (i.e., only NO-releasing or only QA-functionalized) and dual (i.e., NO-releasing and QA-functionalized) functional nanoparticles were tested against Grampositive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa. Particles with only NO release capabilities alone were found to be more effective against P. aeruginosa, while particles with only QA-functionalities exhibited greater toxicity toward S. aureus. The minimum bactericidal concentrations (MBC) of QA-functionalized particles decreased with increasing alkyl chain length against both microbes tested. Combining NO release and QA-functionalities on the same particle resulted in an increase in bactericidal efficacy against S. aureus; however, no change in activity against P. aeruginosa was observed compared to NO-releasing particles alone.

Carpenter, Alexis W.; Worley, Brittany V.; Slomberg, Danielle L.; Schoenfisch, Mark H.

2012-01-01

70

Microbial community adaptation to quaternary ammonium biocides as revealed by metagenomics.  

PubMed

Quaternary ammonium compounds (QACs) represent widely used cationic biocides that persist in natural environments. Although microbial degradation, sensitivity and resistance to QACs have been extensively documented, a quantitative understanding of how whole communities adapt to QAC exposure remain elusive. To gain insights into these issues, we exposed a microbial community from a contaminated river sediment to varied levels of benzalkonium chlorides (BACs, a family of QACs) for 3 years. Comparative metagenomic analysis showed that the BAC-fed communities were dramatically decreased in phylogenetic diversity compared with the control (no BAC exposure), resulting presumably from BAC toxicity, and dominated by Pseudomonas species (>?50% of the total). Time-course metagenomics revealed that community adaptation occurred primarily via selective enrichment of BAC-degrading Pseudomonas populations, particularly P.?nitroreducens, and secondarily via amino acid substitutions and horizontal transfer of a few selected genes in the Pseudomonas populations, including a gene encoding a PAS/PAC sensor protein and ring-hydroxylating dioxygenase genes. P.?nitroreducens isolates were reproducibly recoverable from communities after prolonged periods of no-BAC exposure, suggesting that they are robust BAC-degraders. Our study provides new insights into the mechanisms and tempo of microbial community adaptation to QAC exposure and has implications for treating QACs in biological engineered systems. PMID:23731340

Oh, Seungdae; Tandukar, Madan; Pavlostathis, Spyros G; Chain, Patrick S G; Konstantinidis, Konstantinos T

2013-06-03

71

The role of the qacA gene in mediating resistance to quaternary ammonium compounds.  

PubMed

Conditions facilitating resistance to quaternary ammonium compounds (QACs) were investigated in Staphylococcus aureus SK982 exposed to benzalkonium chloride (BAC; a member of QACs) under various circumstances. S. aureus SK982 carrying the qacA gene encoding for resistance to QACs was grown in the presence of stable or gradually increasing concentrations of BAC, or it was exposed to this antiseptic in the exponential phase of growth. Bacteria cultivated in the highest BAC concentrations that did not retard their growth comparing to the untreated control were subjected to real-time quantitative polymerase chain reaction analysis for relative expression of the efflux genes qacA and norA. Under such conditions, S. aureus SK982 tolerated a relatively low stable concentration of BAC (1.22?mg/L) when compared with a gradually increasing antiseptic concentration (tolerance of 4.88?mg/L). However, in both cases, qacA expression was not significant. The culture exposed in the exponential phase of growth tolerated the highest concentration of BAC (9.76?mg/L) as also accompanied by significant overexpression of qacA. Expression of norA was relatively low regardless of the conditions tested. It seems that under the short-term conditions, the phase of bacterial growth is more important for the expression of BAC resistance than the capability to adapt to this antiseptic. This study provides a deeper insight into the relevance of the qac genes in conferring resistance to QACs. PMID:23256651

Cervinkova, Dana; Babak, Vladimir; Marosevic, Durdica; Kubikova, Iva; Jaglic, Zoran

2012-12-20

72

Incidence of Class 1 Integrons in a Quaternary Ammonium Compound-Polluted Environment  

PubMed Central

Samples of effluent and soil were collected from a reed bed system used to remediate liquid waste from a wool finishing mill with a high use of quaternary ammonium compounds (QACs) and were compared with samples of agricultural soils. Resistance quotients of aerobic gram-negative and gram-positive bacteria to ditallowdimethylammomium chloride (DTDMAC) and cetyltrimethylammonium bromide (CTAB) were established by plating onto nutrient agar containing 5 ?g/ml or 50 ?g/ml DTDMAC or CTAB. Approximately 500 isolates were obtained and screened for the presence of the intI1 (class 1 integrase), qacE (multidrug efflux), and qacE?1 (attenuated qacE) genes. QAC resistance was higher in isolates from reed bed samples, and class 1 integron incidence was significantly higher for populations that were preexposed to QACs. This is the first study to demonstrate that QAC selection in the natural environment has the potential to coselect for antibiotic resistance, as class 1 integrons are well-established vectors for cassette genes encoding antibiotic resistance.

Gaze, W. H.; Abdouslam, N.; Hawkey, P. M.; Wellington, E. M. H.

2005-01-01

73

75 FR 40729 - Residues of Quaternary Ammonium Compounds, N-Alkyl (C12-14  

Federal Register 2010, 2011, 2012, 2013

...ethylbenzyl ammonium chloride on food contact surfaces when applied/used in public...tolerance residues in food resulting from contact with surfaces treated with antimicrobial...305-5805. FOR FURTHER INFORMATION CONTACT: Velma Noble, Antimicrobials...

2010-07-14

74

Efficient quaternary ammonium salt as corrosion inhibitor for steel pickling in sulphuric acid media  

Microsoft Academic Search

A study is carried out on the resistance to corrosion of mild steel in 5 per cent H2SO4 solutions at temperatures between 30 and 60°C. The effectiveness of quaternary ammonium salt used as corrosion inhibitor under the same experimental conditions was also investigated. Weight loss results and electrochemical data showed the good inhibiting action of the inhibitor, acting as anodic

H. A. El Dahan; T. Y. S. Mohamed; S. A. Abo El-Enin

1999-01-01

75

New biomaterials through surface segregation phenomenon: New quaternary ammonium compounds as antibacterial agents  

Microsoft Academic Search

Five new trisiloxane quaternary ammonium compounds were synthesized from hydro-trisiloxane with allyl glycidyl ether to yield the epoxy function. Various amines were then reacted to yield trisiloxane amines which were further reacted to methyl substitute or oxidize the ?-carbons in order to provide thermal stability. These new compounds were employed as melt additives in a nonwoven polypropylene fiber extrusion process

Ronald S. Nohr; J. Gavin Macdonald

1994-01-01

76

Methodological approach towards the environmental significance of uncharacterized substances — quaternary ammonium compounds as an example  

Microsoft Academic Search

The European Commission has presented a list of priority substances in addition to the Water Framework Directive (WFD) adopted in December 2000. The list of priority substances is a matter of continuous review hence other relevant substances identified as hazardous can be implemented for regulation. In that regard a group of potential hazardous substances, quaternary ammonium compounds (QAC) is selected

Norbert Kreuzinger; Maria Fuerhacker; Sigrid Scharf; Maria Uhl; Oliver Gans; Britta Grillitsch

2007-01-01

77

Permeability and thermodynamics study of quaternary ammonium surfactants—phosphocholine vesicle system  

Microsoft Academic Search

Quaternary ammonium compounds (QACs) are recognized as membrane active agents widely used as biocides. The main purpose of this work was to investigate the influence of the QAC head group and acyl chain length on their permeability-perturbing power and on their affinity for lipidic membranes. Permeability perturbations were assessed by measuring the release of calcein entrapped inside vesicles. The affinity

Lucie Marcotte; Jean Barbeau; Michel Lafleur

2005-01-01

78

Ionometric determination of quaternary ammonium cations in industrial extraction reagents and sewage  

Microsoft Academic Search

When extraction reagents based on salts of quaternary ammonium bases (QAS) are used in the technology of purification of rare earth elements (REE), the problem arises of determining QAS in technological and dilute aqueous solutions (circulating waters and sewage). A direct method of determining cations of QAS is known, based on the use of ion-selective electrodes, reversible to hydrophobic cations.

V. V. Kokovkin; A. M. Nemirovskii; L. Kh. Kravchenko; B. S. Smolyakov

1988-01-01

79

Analysis of polymeric quaternary ammonium salts as found in cosmetics by metachromatic polyelectrolyte titration  

Microsoft Academic Search

Metachromatic polyelectrolyte titration was investigated as a means of analyzing polymeric quaternary ammonium salts (polyquaterniums) of relatively low charge density used as ingredients in cosmetics. They are of possible toxicological concern, but little is known of their environmental fate and behavior. With o-toluidine blue as the indicator, determination of the concentration of a range of polyquaterniums of commercial importance and

J. L. Cumming; D. W. Hawker; C. Matthews; H. F. Chapman; K. Nugent

2010-01-01

80

Effects of Quaternary-Ammonium-Based Formulations on Bacterial Community Dynamics and Antimicrobial Susceptibility  

Microsoft Academic Search

Quaternary ammonium compounds (QACs) are widely used as adjuncts to hygiene in domestic cleaning products. Current concern that the increased use of such biocides in consumer products might contribute to the emergence of antibiotic resistance has led us to examine the effects of a QAC-containing domestic cleaning fluid on the population dynamics and antimicrobial susceptibility of domestic sink drain biofilm

Andrew J. McBain; Ruth G. Ledder; Louise E. Moore; Carl E. Catrenich; Peter Gilbert

2004-01-01

81

Quaternary Ammonium Salts From Hydrolysed Fatty Oil Based on Novel Tertiary Amines Used as Corrosion Inhibitors for Pipelines Carbon Steel at Acid Job in Petroleum Industry  

Microsoft Academic Search

Ten new quaternary ammonium salts were designed and synthesized from hydrolyzed fatty oils; the hydrolysed oils were used as a source of alkyl halides to prepare the quaternary ammonium salts by refluxing the fatty alkyl halide with ethoxylated amines as untraditional 3° amines in acetone. The structure of the prepared quaternary ammonium salts were characterized by FTIR and H NMR

A. M. Al-Sabagh; N. G. Kandile; Nahed Amer; Omaima Ramadan; E. A. Khamis

2011-01-01

82

Potentiometric microtitration of anions with quaternary ammonium halides  

Microsoft Academic Search

Summary Cetyltrimethylammonium bromide has been evaluated for the potentiometric precipitation titration of some water-soluble organic anions. Emf's were monitored with a fluoroborate ion-selective electrode and a double-junction reference electrode. The perchlorate, nitrate, and calcium electrodes also respond to the various anions. Cetyltrimethylammonium chloride and cetylpyridinium chloride are also suitable as titrants for the various anions. They can be used also

Walter Selig

1979-01-01

83

Site of Action of Certain Antibacterial Heterocyclic Quaternary Ammonium Compounds  

PubMed Central

The site of action of related mono- and bis-quinaldinium compounds was investigated in Staphylococcus aureus and Bacillus megaterium. The effects of these compounds on cell morphology and on protoplast formation and fragility were studied, and the distribution of C14-labeled quinaldinium compound in cell fractions was measured. The latter studies showed that a major part of the quaternary compound penetrates the cell, leaving a very small quantity associated with the cell wall. Similar antibacterial effects were seen with both the mono- and bis-quinaldinium compounds studied, and these effects were comparable with antibacterial properties of known cationic surface-active antibacterial agents. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9

Cox, W. A.

1965-01-01

84

Tumor growth inhibition by ammonium chloride-induced acidosis.  

PubMed

Ammonium chloride-induced metabolic acidosis decreases the growth of various experimental tumors. Spleen exhibits the same effects. There is a sex factor which seems to affect the growth of both tumor and spleen. The observed tumor inhibition appears to be related to a systemic impairment of the anabolic mechanisms. The decrease in tumor calcium suggests that this element may play a role in the tissue growth. The possible implication of cell membrane changes and of a block in glycolysis in the acidosis effects are discussed. PMID:51839

Anghileri, L J

1975-10-01

85

New biocide with both N-chloramine and quaternary ammonium moieties exerts enhanced bactericidal activity.  

PubMed

Considering the rise of antibiotic resistance, the development of new antibacterial agents with improved biocidal functions is urgently required. In this study, ionic 5,5-dimethylhydantoin (DMH) analogues containing either a quaternary ammonium moiety (2)-4) or a phosphonate functional group (5),-6), were designed and synthesized to investigate the possible enhancing effect of quaternary ammonium moieties on the antibacterial performance of N-chloramines. These ionic DMH analogues were converted to their N-chloramine counterparts either in free form or after being covalently immobilized on a polymer surface via the "click" chemistry method. In the subsequent antimicrobial assessment against multi-drug-resistant Escherichia coli (MDR-E. coli) and methicillin-resistant Staphylococcus aureus (MRSA), chlorinated 2 and 3, the cyclic N-chloramines with a structural cation, exhibited distinctly enhanced biocidal functions in solution and after immobilization on surfaces. PMID:23184796

Li, Lingdong; Pu, Tianyun; Zhanel, George; Zhao, Nan; Ens, Werner; Liu, Song

2012-07-03

86

Fine silica powder modified with quaternary ammonium group 3. The adsorption behavior of anionic surfactants  

Microsoft Academic Search

The adsorption, zeta potential, and mean particle size of fine silica powder modified with quaternary ammonium groups having alkyl chains of various lenghts (?N+(CmH2m + 1)(CH3)2, XNm, m = 4, 6, 8, 10, 12, 14, 16, and 18) were measured as a function of the concentration of the anionic surfactant (sodium dodecyl sulfate or sodium tetradecyl sulfate) in the suspensions.

Tsuneo Suhara; Hiroshi Fukui; Michihiro Yamaguchi; Fukuji Suzuki

1996-01-01

87

Effect of quaternary ammonium substitution of hydroxyethylcellulose on binding of dodecyl sulfate  

Microsoft Academic Search

The binding behavior of sodium dodecyl sulfate (SDS) to quater-nary ammonium substituted hydroxyethylcellulose (cationic cellu-lose)\\u000a of varying degree of substitution was studied by the following measurements: binding isotherms of SDS to cationic cellulose,\\u000a dye solubilization of the cationic cellulose\\/SDS complex, partial molal volume of each cationic cellulose, and spin-lattice\\u000a relaxation time of SDS protons in the course of binding. Binding

K. Ohbu; O. Hiraishi; I. Kashiwa

1982-01-01

88

Determination of homologues of quaternary ammonium surfactants by capillary electrophoresis using indirect UV detection  

Microsoft Academic Search

This investigation describes the simultaneous separation of two major non-chromophoric quaternary ammonium surfactants, alkyltrimethyl- and dialkyldimethylammonium compounds (ATMACs and DADMACs, respectively), by capillary electrophoresis (CE) using indirect UV detection. The most effective separation conditions was 10mM phosphate buffer with 57.5% tetrahydrofuran and 3mM sodium dodecyl sulfate (SDS) at pH 4.3, and the sample hydrodynamic injection of up to 20s at

Hsueh-Ying Liu; Wang-Hsien Ding

2004-01-01

89

In Vivo Antimalarial Activities of Mono- and Bis Quaternary Ammonium Salts Interfering with Plasmodium Phospholipid Metabolism  

PubMed Central

We previously showed that quaternary ammonium salts have potent antimalarial activities against the blood stage of drug-resistant Plasmodium falciparum. In the present study, 13 compounds of this series were comparatively assessed in murine in vivo malarial models. Mice infected with Plasmodium berghei were successfully treated with 11 quaternary ammonium salts in a 4-day suppressive test with a once-daily intraperitoneal administration. The dose required to decrease parasitemia by 50% (ED50) ranged from 0.04 to 4.5 mg/kg of body weight. For six mono- and three bis-quaternary ammonium salts, the therapeutic indices (i.e., 50% lethal dose and ED50) were higher than 5, and at best, around 20 to 30 for five of them (E6, E8, F4, G5, and G25), which is comparable to that of chloroquine under the same conditions. Plasmodium chabaudi was significantly more susceptible to G5, G15, and G25 compounds than P. berghei. Similar therapeutic indices were obtained, regardless of the administration mode or initial parasitemia (up to 11.2%). Parasitemia clearance was complete without recrudescence. Subcutaneously administered radioactive compounds had a short elimination half-life in mice (3.5 h) with low bioavailability (17.3%), which was likely due to the permanent cationic charge of the molecule. The high in vivo therapeutic index in the P. chabaudi-infected mouse model and the absence of recrudescence highlight the enormous potential of these quaternary ammonium salts for clinical malarial treatment.

Ancelin, Marie L.; Calas, Michele; Bonhoure, Anne; Herbute, Serge; Vial, Henri J.

2003-01-01

90

Extraction of quaternary ammonium salts from aqueous solutions by sorption with hydrolyzed lignin  

SciTech Connect

The sorption of surfactant quaternary ammonium salts by hydrolized lignin, recovered from the hydrolysis of wood and other plant materials, was studied in the context of the purification of low-concentration aqueous effluents. Infrared spectroscopy of the samples was conducted. Calculations showed that the relative intensity of the absorption bands of the hydrolized lignin before and after sorption of the surfactant changed by 0.8 to 5%. Sorption isotherms were also determined.

Nikiforov, A.F.; Astaf'eva, O.V.; Lobukhina, T.V.

1987-12-01

91

Antifungal properties of new quaternary ammonium compounds in relation to their surface activity  

Microsoft Academic Search

The biological activity of 17 potential wood preservatives—quaternary ammonium and imidazolium compounds—was determined employing screening agar-plate and agar-block methods. Experiments were carried out on Scots pine (Pinus sylvestris L.) wood. The fungicidal value of new compounds with cycloalkyl substituents for Coniophora puteana ranged from 0.64 kg\\/m3 to 2.2 kg\\/m3. Aspergillus niger turned out to be the most resistant fungus to the action

Jadwiga Zabielska-Matejuk

2005-01-01

92

Development of a method for fabrication of modified viscose fibre containing quaternary ammonium salts  

Microsoft Academic Search

UDC 677.46:661.183.123.3 A continuous one-stage method for fabrication of modified viscose fibre containing quaternary ammonium groups was developed. Ways of increasing the CMGP were defined. It was shown that CMGP increases sharply on simultaneous addition of Na2SO 4 and MBAA (N,N'-methylenebisacrylamide) (MBMAA: N,N'-methylenebismethacrylamide) was developed. A viscose fibre containing up to 80 wt. % graft PDMVPMS with CMGP of up

M. A. Penenzhik; L. P. Berdnikova; A. D. Virnik

1994-01-01

93

Demulsification of bitumen emulsions using branched water soluble quaternary ammonium-containing polymers  

SciTech Connect

A process for recovering bitumen from oil-in-water (O/w) emulsions is disclosed wherein water soluble demulsifiers are used. These demulsifiers are branched water-soluble quaternary ammonium-containing polymers. To resolve the bituminous petroleum emulsions, the process is carried out between 25/sup 0/ and 160/sup 0/ C wherein the demulsifier of the invention is contacted with the bituminous emulsion.

Mccoy, D.R.

1983-05-24

94

Biodegradation of new quaternary ammonium compounds in treated wood by mould fungi  

Microsoft Academic Search

The degradation of seven potential wood preservatives based on imidazolium compounds (ICs) and quaternary ammonium compounds (QACs) with a modified anion structure by mould fungi was determined using soil-block method. Experiments were carried out on Scots pine (Pinus sylvestris L.) wood. Two-phase titration and high-performance liquid chromatography (HPLC) method were used to detect and quantify the degradation products. The performed

Jadwiga Zabielska-Matejuk; Katarzyna Czaczyk

2006-01-01

95

Potentiometric titration of long chain quaternary ammonium compounds using sodium tetraphenyl borate  

Microsoft Academic Search

Current methods for determining the activity of long chain quaternary ammonium compounds (QACS) are based either on dye partition,\\u000a titration, or colorimetric analysis. The two major disadvantages of these methods are the disparity of partition coefficients\\u000a among differently constituted QACS and the difficulty in detecting visual end points. Some potentiometric titration methods\\u000a for QACS have been reported in the literature.

C. N. Wanga; L. D. Metcalfea; J. J. Donkerbroek; A. H. M. Cosijn

1989-01-01

96

Microemulsions with excellent water solubilizing capacity at high hydrocarbon levels with quaternary ammonium salts as surfactants  

Microsoft Academic Search

In W\\/O microemulsions prepared by adding dry surfactant to a mixture of 85% heptane or toluene and 15% pentanol, then titrating\\u000a with water, systems using quaternary ammonium salts have been shown to be capable of solubilizing much larger amounts of water\\u000a than systems using the anionic sodium dodecyl sulfate. In homologous series in the range C12 to C16 it would

Raymond L. Venable

1985-01-01

97

Desorption followed with radioisotopes and membrane potentials in perfluorinated vinyl4pyridine and quaternary ammonium membranes  

Microsoft Academic Search

A radiotracer technique used to follow desorption and exchange processes with vinyl4pyridine (V4P) and quaternary ammonium membranes (QAM) allowed one to compare the properties of these two types of membranes and to point out the deprotonation process in V4P membranes. Exchange capacities obtained with this technique were compared with those obtained by microanalysis titration of nitrogen from V4P exchange sites.

Joseph Denamganai; François Schue; Joseph Sledz; Jean Molenat

1995-01-01

98

Synthesis of Quaternary Ammonium Salts of Tricyclic Cationic Drugs: A One-Pot Synthesis for the Bioorganic Chemistry Laboratory  

ERIC Educational Resources Information Center

|A one-pot conversion of tricyclic cationic drugs to their quaternary ammonium forms is described for a widely used bioactive drug: chlorpromazine, a phenothiazine-based antipsychotic. After conversion to its free base, the parent drug was methylated using substoichiometric amounts of methyl iodide dissolved in ether; the charged quaternary…

Brunauer, Linda S.; Mogannam, Abid C.; Hwee, Won B.; Chen, James Y.

2007-01-01

99

Synthesis of Quaternary Ammonium Salts of Tricyclic Cationic Drugs: A One-Pot Synthesis for the Bioorganic Chemistry Laboratory  

ERIC Educational Resources Information Center

A one-pot conversion of tricyclic cationic drugs to their quaternary ammonium forms is described for a widely used bioactive drug: chlorpromazine, a phenothiazine-based antipsychotic. After conversion to its free base, the parent drug was methylated using substoichiometric amounts of methyl iodide dissolved in ether; the charged quaternary…

Brunauer, Linda S.; Mogannam, Abid C.; Hwee, Won B.; Chen, James Y.

2007-01-01

100

Morphology Control of Zn-SiO2 Composite Films Electrodeposited from Aqueous Solution Containing Quaternary Ammonium Cations  

NASA Astrophysics Data System (ADS)

Zn-SiO2 alloys were electrodeposited from acidic aqueous solution containing cationic surfactants such as diallyl-dimethyl-ammonium chloride, trimethyl-tetradecyl-ammonium chloride, trimethyl-stearyl-ammonium chloride and dimethyl-distearyl-ammonium chloride. Zn-SiO2 alloy thin films were obtained at the wide current density range from 5 A/dm2 to 100 A/dm2. SiO2 content in deposits was ca. 10 % at the maximum using the solution containing a surfactant with molecular weight range of 200 to 300.

Ohgai, T.; Ogushi, K.; Takao, K.

2013-03-01

101

Action of Disinfectant Quaternary Ammonium Compounds against Staphylococcus aureus?  

PubMed Central

Mode-of-action studies concluded that alkyldimethylbenzylammonium chloride (ADBAC) (a blend of C12, C14 and C16 alkyl homologues) and didecyldimethylammonium chloride (DDAC) are both membrane-active agents, possessing subtly different modes of action reflecting early cell interactions against Staphylococcus aureus. ADBAC and DDAC exhibited similar MIC behaviors from 0.4 ppm to 1.8 ppm over an inoculum range of 1 × 105 to 1 × 109 CFU/ml at 35°C. For ADBAC and DDAC, an increased rapidity of killing against S. aureus (final concentration, 2 × 109 CFU/ml) was observed at 35°C compared to 25°C. Concentration exponents (?) for killing were <2.5 for both agents, and temperature influenced the ? value. Examination of leakage and kill data suggested that a single leakage marker was not indicative of cell death. ADBAC and DDAC possessed Langmuir (L4) and high-affinity (H3/4) uptake isotherms, respectively. ADBAC molecules formed a single monolayer of coverage of cells at the end of primary uptake, and DDAC formed a double monolayer. Rapid cell leakage occurred at bactericidal concentrations, with total depletion of the intracellular potassium and 260-nm-absorbing pools released in this strict order. Autolysis was observed for ADBAC and DDAC at concentrations of 9 ?g/ml (0.0278 mM and 0.0276 mM, respectively) and above, together with the depletion of approximately 30% of the internal potassium pool. Autolysis contributed to ADBAC and DDAC lethality, although high biocide concentrations may have inhibited autolytic enzyme activity.

Ioannou, Christopher J.; Hanlon, Geoff W.; Denyer, Stephen P.

2007-01-01

102

Synthesis and corrosion inhibition study of some 1,6-hexanediamine-based N, N-diallyl quaternary ammonium salts and their polymers  

Microsoft Academic Search

A variety of unsaturated N,N-diallyl compounds, capable of undergoing cyclopolymerization, are prepared from 1,6-hexanediamine. Selective monoformylation followed by allylation of the diamine afforded N,N-diallyl-N?-formyl-1,6-hexanediamine (DFH). The DFH was converted into quaternary ammonium monomers N,N-diallyl-N-carboethoxymethyl-N?-formyl-1,6-hexanediamine (DCFH) and N,N-diallyl-N-benzyl-N?-formyl-1,6-hexanediamine (DBFH)by reacting with ethyl chloroacetate and benzyl chloride, respectively. The monomer DCFH on homo- and co-polymerization (with SO2) afforded the polyelectrolytes poly(DFCH) and

Sk. A Ali; M. T Saeed

2001-01-01

103

Liquid-liquid phase separation in particles containing organics mixed with ammonium sulfate, ammonium bisulfate, ammonium nitrate or sodium chloride  

NASA Astrophysics Data System (ADS)

As the relative humidity varies from high to low values in the atmosphere, particles containing organics and inorganic salts may undergo liquid-liquid phase separation. The majority of the laboratory work on this subject has used ammonium sulfate as the inorganic salt. In the following we studied liquid-liquid phase separation in particles containing organics mixed with the following salts: ammonium sulfate, ammonium bisulfate, ammonium nitrate and sodium chloride. In each experiment one organic was mixed with one inorganic salt and the liquid-liquid phase separation relative humidity (SRH) was determined. Since we studied 23 different organics mixed with four different salts, a total of 92 different particle types were investigated. Out of the 92 types, 49 underwent liquid-liquid phase separation. For all the inorganic salts, liquid-liquid phase separation was never observed when the oxygen-to-carbon elemental ratio (O:C) was ? 0.8 and was always observed for O:C<0.5. For 0.5 ? O:C< 0.8, the results depended on the salt type. Out of the 23 organics investigated, the SRH of 20 organics followed the trend: (NH4)2SO4 ? NH4HSO4 ? NaCl ? NH4NO3. This trend is consistent with previous salting-out studies and the Hofmeister series. Based on the range of O:C values found in the atmosphere and the current results, liquid-liquid phase separation is likely a frequent occurrence in both marine and non-marine environments.

You, Y.; Renbaum-Wolff, L.; Bertram, A. K.

2013-07-01

104

Long-Term Ammonium Chloride or Sodium Bicarbonate Treatment in Two Models of Polycystic Kidney Disease  

Microsoft Academic Search

Administration of ammonium chloride aggravates, while short-term administration of sodium or potassium bicarbonate lessens the development of polycystic kidney disease in Han:SPRD rats. We have conducted studies to determine whether the protection afforded by the administration of sodium bicarbonate is sustained and prevents development of uremia during chronic administration and whether the effects of the administration of ammonium chloride and

Vicente E. Torres; Michael G. Branden; Izumi Yoshida; Vincent H. Gattone

2001-01-01

105

Ammonium chloride influences in vitro-neuronal network activity.  

PubMed

The objective of the present work is to image functional alterations in hepatic encephalopathy (HE) by ammonia-induced changes of in vitro-neuronal network activity and to identify counteracting strategies. Synchronous bursting behavior of rat cortical cells which is the result of synaptic interaction of excitatory and inhibitory neurons was recorded in vitro on microelectrode arrays (MEAs) after ammonium chloride exposure. In order to test the involvement of astrocytic glutamine metabolism and N-methyl-d-aspartic acid- (NMDA-) receptor function in the observed ammonia-induced network dysregulation and to identify potentially protective strategies, we investigated effects of the glutamine synthetase (GS) inhibitor methionine-sulfoximine (MSO) and the NMDA-receptor antagonist DL-2-Amino-5-phosphono-pentanoic acid (AP-5), respectively. We observed a characteristic ammonia-induced increase of global network activity while network synchrony was suppressed. The increase of global activity, but not the suppression of network synchrony was prevented by inhibiting GS. However, blocking NMDA-receptors prevented both, network excitation and desynchronization. Conclusions: 1. The observed desynchronization of in vitro-neuronal network activity after ammonium chloride treatment might reflect global neuronal network changes in HE in vivo and suggests the MEA technology as a valuable tool for measuring changes of neuronal connectivity in vitro. 2. Astrocytic glutamine metabolism might be involved in increased global network activity, but not in the suppression of network synchrony. 3. Overactivation of NMDA-receptors might underlie both, the ammonia-induced increase of activity and suppression of network synchrony, suggesting that NMDA-receptor function is involved in HE and that their blockage might be protective. 4. Measuring neuronal network activity in vitro by the MEA technology might help to describe functionally protective measures in HE. PMID:22421534

Schwarz, Clara-Sophie; Ferrea, Stefano; Quasthoff, Kim; Walter, Janine; Görg, Boris; Häussinger, Dieter; Schnitzler, Alfons; Hartung, Hans-Peter; Dihné, Marcel

2012-03-07

106

Determination of residues of quaternary ammonium disinfectants in food products by liquid chromatography-tandem mass spectrometry.  

PubMed

A liquid chromatography-tandem mass spectrometry method has been developed for the determination of residues of alkylbenzyldimethylammonium, didecyldimethylammonium, didodecyldimethylammonium, and benzyldodecylhydroxyethylammonium compounds in various food matrixes. These quaternary ammonium compounds (QAs) are used in the food industry as disinfectants. According to the Dutch Food Law, the total mass (expressed as cetyltrimethylammonium chloride) of QAs in food products shall not exceed the legislative limit of 0.5 mg/kg. Samples were extracted by a simple salting-out procedure, using acetonitrile and sodium chloride; about 100 samples could be prepared and analyzed daily. Special care had to be taken to thoroughly homogenize samples and to avoid the use of contaminated labware. The method was validated by a procedure in compliance with EU Directive 2002/657. From the matrixes of ice cream and minced meat, recoveries of more than 95% with a relative standard deviation of about 3% were obtained by 3 different analysts (n = 54). Detection limits were in the low microg/kg range. The decision limit (CCalpha) was determined to be 0.55 mg/kg. Dairy and meat products, collected in The Netherlands, were analyzed (761 samples). In 1% of the meat samples, 2% of the ice cream and milkshake samples, and 24% of the whipped cream samples, the Dutch legislative limit was exceeded. Over 2000 injections could be performed on a single column without deterioration of the peak shapes or recoveries. PMID:15295898

van Bruijnsvoort, Michel; Rooselaar, Joop; Stern, Alfred G; Jonker, Klaas M

107

Response to Metabolic (Ammonium Chloride) Acidosis at Sea Level and at High Altitude  

Microsoft Academic Search

Summary Ammonium chloride was intravenously infused in a group of sea-leve. residents and in a group of high-altitude natives living at 4300 m above sea level. Blood pH, and buffer base; plasma bicarbonate, chloride, sodium and potassium; and urine pH, ammonium and titratable acidity were determined before and after the ammonium infusion. Blood pH, pCO2 blood buffer base, serum bicarbonate

R. Lozano; C. Torres; C. Marchena; J. Whittembury; C. C. Monge

1969-01-01

108

Surface tension and micellization properties of heterogemini surfactants containing quaternary ammonium salt and sulfobetaine moiety  

Microsoft Academic Search

A novel gemini surfactant with two hydrocarbon chains and two different hydrophilic parts containing a quaternary ammonium salt and a sulfobetaine moiety, N,N-dimethyl-N-{2-[N?-methyl-N?-(3-sulfopropyl)-alkylammonium]ethyl}-1-alkylammonium bromides (2CnAmSb, where n represents hydrocarbon chain lengths of 8, 10, 12, and 14), was synthesized by reacting N,N,N?-trimethylethylenediamine with n-alkyl bromide, followed by reacting with 1,3-propane sultone. The adsorption and aggregation properties of 2CnAmSb in the

Kanae Nyuta; Tomokazu Yoshimura; Kunio Esumi

2006-01-01

109

Ionometric determination of quaternary ammonium cations in industrial extraction reagents and sewage  

SciTech Connect

When extraction reagents based on salts of quaternary ammonium bases (QAS) are used in the technology of purification of rare earth elements (REE), the problem arises of determining QAS in technological and dilute aqueous solutions (circulating waters and sewage). A direct method of determining cations of QAS is known, based on the use of ion-selective electrodes, reversible to hydrophobic cations. Two types of procedures can be distinguished within the framework of this method: potentiometric titration and direct potentiometry. In this work the authors discuss the possibilities of both types for practical use in industrial analysis.

Kokovkin, V.V.; Nemirovskii, A.M.; Kravchenko, L.Kh.; Smolyakov, B.S.

1988-01-01

110

Adsorption of chromium (VI) from aqueous solutions by cellulose modified with ?-CD and quaternary ammonium groups.  

PubMed

Cellulose powder was grafted with the vinyl monomer glycidyl methacrylate using ceric ammonium nitrate as initiator and was further derived with ?-CD and quaternary ammonium groups to build Cell-g-GMA-?-CDN(+) adsorbent. Epoxy cellulose was made up of Cell-g-GMA and Cell-hydro-g-GMA, and was found to contain 3.71 mmol g(-1) epoxy groups. The adsorption process of the modified cellulose was described by the Langmuir model of adsorption well, and the maximum adsorption capacity of chromium (VI) reached 61.05 mg g(-1). The adsorption-desorption tests of ?-CDN(+)-type cellulose derivatives exhibited that the reproducibility of the adsorbent was well and the adsorbent could be reused five times at least. PMID:21277080

Zhou, Yanmei; Jin, Qiang; Zhu, Tianwei; Akama, Yoshifumi

2011-01-14

111

Analysis of quaternary ammonium and phosphonium ionic liquids by reversed-phase high-performance liquid chromatography with charged aerosol detection and unified calibration.  

PubMed

Several hydrophobic ionic liquids (ILs) based on long-chain aliphatic ammonium- and phosphonium cations and selected aromatic anions were analyzed by reversed-phase high-performance liquid chromatography (RP-HPLC) employing trifluoroacetic acid as ion-pairing additive to the acetonitrile-containing mobile phase and adopting a step-gradient elution mode. The coupling of charged aerosol detection (CAD) for the non-chromophoric aliphatic cations with diode array detection (DAD) for the aromatic anions allowed their simultaneous analysis in a set of new ILs derived from either tricaprylmethylammonium chloride (Aliquat 336) and trihexyltetradecylphosphonium chloride as precursors. Aliquat 336 is a mix of ammonium cations with distinct aliphatic chain lengths. In the course of the studies it turned out that CAD generates an identical detection response for all the distinct aliphatic cations. Due to lack of single component standards of the individual Aliquat 336 cation species, a unified calibration function was established for the quantitative analysis of the quaternary ammonium cations of the ILs. The developed method was validated according to ICH guidelines, which confirmed the validity of the unified calibration. The application of the method revealed molar ratios of cation to anion close to 1 indicating a quantitative exchange of the chloride ions of the precursors by the various aromatic anions in the course of the synthesis of new ILs. Anomalies of CAD observed for the detection of some aromatic anions (thiosalicylate and benzoate) are discussed. PMID:18805540

Stojanovic, Anja; Lämmerhofer, Michael; Kogelnig, Daniel; Schiesel, Simone; Sturm, Martin; Galanski, Markus; Krachler, Regina; Keppler, Bernhard K; Lindner, Wolfgang

2008-09-11

112

Determination of selected quaternary ammonium compounds by liquid chromatography with mass spectrometry. Part II. Application to sediment and sludge samples in Austria.  

PubMed

Soxhlet extraction and high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry detection (MS/MS) was used for the determination of selected quaternary ammonium compounds (QACs) in solid samples. The method was applied for the determination of alkyl benzyl, dialkyl and trialkyl quaternary ammonium compounds in sediment and sludge samples in Austria. The overall method quantification limits range from 0.6 to 3 microg/kg for sediments and from 2 to 5 microg/kg for sewage sludges. Mean recoveries between 67% and 95% are achieved. In general sediments were especially contaminated by C12 chain benzalkonium chloride (BAC-C12) as well as by the long C-chain dialkyldimethylammonium chloride (DDAC-C18) with a maximum concentration of 3.6 mg/kg and 2.1mg/kg, respectively. Maxima of 27 mg/kg for DDAC-C10, 25 mg/kg for BAC-C12 and 23 mg/kg for BAC-C14 were determined for sludge samples. The sums of the 12 selected target compounds range from 22 mg/kg to 103 mg/kg in the sludge samples. PMID:17011092

Martínez-Carballo, Elena; González-Barreiro, Carmen; Sitka, Andrea; Kreuzinger, Norbert; Scharf, Sigrid; Gans, Oliver

2006-09-28

113

Synthesis and Characterization of Poly(vinyl alcohol) Membranes with Quaternary Ammonium Groups for Wound Dressing  

Microsoft Academic Search

2-[(acryloyloxy)ethyl]Trimethylammonium chloride (AETMAC) was grafted onto poly(vinyl alcohol) (PVA) using ceric ammonium nitrate (CAN) as a redox initiator. A series of graft co-polymer (PVA-g-PAETMAC) membranes with different contents of AETMAC were prepared with a casting method. The incorporation of AETMAC into PVA chains was confirmed by element analysis and Fourier transform infrared spectroscopy. The effects of grafting on the thermal

Kuo-Yu Chen; Yu-Sheng Lin; Chun-Hsu Yao; Ming-Hsien Li; Jui-Che Lin

2010-01-01

114

Antibacterial activity of reactive quaternary ammonium compounds in solution and in nonleachable coatings.  

PubMed

Antibacterial polymers suitable for coating applications without leaching of the biocidal component have been obtained by UV copolymerization of acrylic resins with acrylic monomers containing quaternary ammonium moieties. Suitable reactive biocides, based on quaternary ammonium monomers (QAMs), endowed with undecylacryloyl group and alkyl chains with 2 (QAM-C2), 8 (QAM-C8), and 16 (QAM-C16) carbon atoms have been synthesized. Aqueous solutions of QAMs showed biocidal activity against Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes strains both in suspension and adhered to stainless steel surfaces. QAM-C16 and QAM-C8 evidenced higher activity toward bacteria in suspension and on stainless steel, respectively. The QAMs have shown sufficient reactivity to be copolymerized, by UV irradiation, with a commercial urethane acrylic resin for coating. Bioactivity tests, performed on free films of crosslinked coatings containing 1% of copolymerized QAM, have shown an increasing inactivation effect in the order of magnitude L. monocytogenes, E. coli, S. aureus with a maximum activity of the QAM-C8. PMID:22186051

Gozzelino, G; Tobar, D E Romero; Chaitiemwong, N; Hazeleger, W; Beumer, R

2011-12-01

115

Quaternary ammonium-type gemini surfactants synthesized from oleic acid: aqueous solution properties and adsorption characteristics.  

PubMed

Cationic gemini surfactants having a quaternary ammonium headgroup have been synthesized from oleic acid. The hydrocarbon chain is covalently bound to the terminal carbonyl group of oleic acid via an amide bond, while the quaternary ammonium headgroup is introduced onto the cis double bond of oleic acid. The Krafft temperature of these surfactants drops below room temperature (ca. 25°C) when the counterion is exchanged from Br? to Cl?. The aqueous solution properties of the Cl series of surfactants have been assessed by means of pyrene fluorescence, dynamic light scattering (DLS), and static surface tension measurements. An increased hydrocarbon chain length results in a lower critical micelle concentration (cmc) and a higher adsorption efficiency at the air/aqueous solution interface. Surface tension measurements suggest the formation of premicelles at concentrations below cmc, whereas, above cmc, DLS indicates the formation of micellar aggregates whose diameter ranges from 5 to 10 nm. We, furthermore, characterized the adsorption of these surfactants to the silica/aqueous solution interface and observed their spontaneous adsorption to the solid surface by electrostatic and intermolecular hydrophobic interactions. The combination of soft-contact imaging atomic force microscopy (AFM) and force-curve data suggests bilayer formation above cmc, which is reflective of the large packing parameter of the gemini surfactants. Interestingly, we found the repulsive interaction observed during compression of the adsorbed layer to be relatively weak, as a result of the low adsorption density and/or the loose molecular packing arrangement, which arises from the asymmetric structure. PMID:23823915

Sakai, Kenichi; Saito, Yuki; Uka, Akihito; Matsuda, Wataru; Takamatsu, Yuichiro; Kitiyanan, Boonyarach; Endo, Takeshi; Sakai, Hideki; Abe, Masahiko

2013-01-01

116

Synthesis and biological evaluation of novel aliphatic amido-quaternary ammonium salts for anticancer chemotherapy: part II.  

PubMed

A series of novel aliphatic amido-quaternary ammonium salts were synthesized and evaluated for their anticancer effects involving induction of RhoB. Most of these compounds, featuring open-ring forms of aliphatic amido-quaternary ammonium salts, exhibited potent anti-proliferative activities in human cancer cell lines, including PC-3, NUGC-3, MDA-MB-231, ACHN, HCT-15, and NCI-H23. In further evaluation, the representative compound N,N-diethyl-N-(2-(N-methyltetradecanamido)ethyl)prop-2-en-1-aminium bromide (3b) exhibited potent pro-apoptotic activity, through RhoB activation, in HeLa cells. PMID:23567950

Yang, Jee Sun; Song, Doona; Ko, Won Jin; Kim, Bunyea; Kim, Bo-Kyung; Park, Song-Kyu; Won, Misun; Lee, Kiho; Lee, Kyeong; Kim, Hwan Mook; Han, Gyoonhee

2013-03-14

117

Adaptation of Pseudomonas sp. Strain 7-6 to Quaternary Ammonium Compounds and Their Degradation via Dual Pathways?  

PubMed Central

Pseudomonas sp. strain 7-6, isolated from active sludge obtained from a wastewater facility, utilized a quaternary ammonium surfactant, n-dodecyltrimethylammonium chloride (DTAC), as its sole carbon, nitrogen, and energy source. When initially grown in the presence of 10 mM DTAC medium, the isolate was unable to degrade DTAC. The strain was cultivated in gradually increasing concentrations of the surfactant until continuous exposure led to high tolerance and biodegradation of the compound. Based on the identification of five metabolites by gas chromatography-mass spectrometry analysis, two possible pathways for DTAC metabolism were proposed. In pathway 1, DTAC is converted to lauric acid via n-dodecanal with the release of trimethylamine; in pathway 2, DTAC is converted to lauric acid via n-dodecyldimethylamine and then n-dodecanal with the release of dimethylamine. Among the identified metabolites, the strain precultivated on DTAC medium could utilize n-dodecanal and lauric acid as sole carbon sources and trimethylamine and dimethylamine as sole nitrogen sources, but it could not efficiently utilize n-dodecyldimethylamine. These results indicated pathway 1 is the main pathway for the degradation of DTAC.

Takenaka, Shinji; Tonoki, Takashi; Taira, Kazuya; Murakami, Shuichiro; Aoki, Kenji

2007-01-01

118

Relative Toxicity of Candidate Mothproofing Uniform Impregnant Didecyl Dimethyl Ammonium Chloride Aliquat 203 Trade Mark.  

National Technical Information Service (NTIS)

The relative toxicity of a candidate uniform mothproofing impregnant didecyl dimethyl ammonium chloride (Aliquat 203) was investigated using mice, rats, guinea pigs, rabbits and humans. The technical grade compound and aqueous solutions of 0.1 percent or ...

M. H. Weeks M. Steinberg S. Rowe R. E. Boldt

1970-01-01

119

Calibration of the On-Line Aerosol Monitor (OLAM) with ammonium chloride and sodium chloride aerosols  

SciTech Connect

The On-Line Aerosol Monitor (OLAM) is a light attenuation device designed and built at the Idaho National Engineering Laboratory (INEL) by EG&G Idaho. Its purpose is to provide an on-line indication of aerosol concentration in the PHEBUS-FP tests. It does this by measuring the attenuation of a light beam across a tube through which an aerosol is flowing. The OLAM does not inherently give an absolute response and must be calibrated. A calibration has been performed at Sandia National Laboratories` (SNL) Sandia Aerosol Research Laboratory (SARL) and the results are described here. Ammonium chloride and sodium chloride calibration aerosols are used for the calibration and the data for the sodium chloride aerosol is well described by a model presented in this report. Detectable instrument response is seen over a range of 0.1 cm{sup 3} of particulate material per m{sup 3} of gas to 10 cm{sup 3} of particulate material per m{sup 3} of gas.

Brockmann, J.E.; Lucero, D.A.; Romero, T. [Sandia National Labs., Albuquerque, NM (United States); Pentecost, G. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1993-12-01

120

Surface and thermodynamic parameters of mixed N -dodecyl N -trimethylsilane ammonium chloride with isooctyl phenol ethoxylate  

Microsoft Academic Search

Isooctyl phenol ethoxylate was mixed with N-dodecyl-N-trimethylsilane ammonium chloride and N-hexadecyl-N-trimethylsilane ammonium chloride, respectively. The surface tensions of aqueous solutions of cationic-nonionic mixtures\\u000a were measured as a function of nonionic concentration at 35C with constant cationic concentration. By using the Hutchinson\\u000a method, the surface excess concentrations, surface mole fractions, and interaction parameters of binary surfactant mixtures\\u000a were calculated. A synergistic

E. A. M. Gad; A. M. A. Omar; M. Zaki

1999-01-01

121

Simultaneous adsorption of sodium dodecyl sulfate and poly(vinyl pyrrolidone) on titanium dioxide with quaternary ammonium groups  

Microsoft Academic Search

Simultaneous adsorption of sodium dodecyl sulfate (SDS) and poly(vinyl pyrrolidone) (PVP) on titanium dioxide with quaternary ammonium groups (XNm, where m is the carbon number of the alkyl chain, 8 and 12) was investigated by measuring the amount of adsorbed SDS and PVP, ? potential, and dispersion stability. The conformation of PVP adsorbed was also estimated using a spin-labeled polymer.

Kunio Esumi; Kenichi Sakai; Kanjiro Torigoe; Tsuneo Suhara; Hiroshi Fukui

1999-01-01

122

Functionalized ionic liquids based on quaternary ammonium cations with three or four ether groups as new electrolytes for lithium battery  

Microsoft Academic Search

New functionalized ILs based on quaternary ammonium cations with three or four ether groups and TFSI? anion were synthesized and characterized. Physical and electrochemical properties, including melting point, thermal stability, viscosity, conductivity and electrochemical stability were investigated for these ILs. Five ILs with lower viscosity in these ILs were applied in lithium battery as new electrolytes. Behavior of lithium redox

Shaohua Fang; Yide Jin; Li Yang; Shin-ichi Hirano; Kazuhiro Tachibana; Shingo Katayama

2011-01-01

123

Effect of Quaternary Ammonium Compounds on Activity of Lactic Acid Starter Bacteria in Milk and Cheese1  

Microsoft Academic Search

The increased application of quaternary ammonium compounds (QAC) for dairy sanitation purposes has stimulated interest in the effect of various con- centrations of these compounds on the growth of lactic acid bacteria in milk. The problem is important from the standpoint of attempts to prevent souring of milk or to reduce bacterial counts prior to delivery to the dairy plant.

D. D. Miller; P. R. Elliker

1951-01-01

124

Effect Of Quaternary Ammonium on Discharge Characteristic of a Non- aqueous Electrolyte Li/O2 Battery.  

National Technical Information Service (NTIS)

The effect of quaternary ammonium on discharge characteristic of Li/O2 cells was studied by using Super-P carbon as air cathode, a 0.2 mol kg(- 1) LiSO3CF3 1:3 (wt.) PC/DME solution as baseline electrolyte, and tetrabutylammonium triflate (NBu4SO3CF3) as ...

D. Foster J. Read S. S. Zhang

2010-01-01

125

Adsorption of phenanthrene by quaternary ammonium surfactant modified peat and the mechanism involved.  

PubMed

Removal of phenanthrene (PHE) from aqueous solution by adsorption onto quaternary ammonium surfactant modified peat was studied. The results show that surfactant modification enhanced the PHE adsorption capacity of peat. Low temperature and neutral pH favored PHE adsorption. Peat modified with long carbon chain surfactant performed better than peat modified with short carbon chain surfactant. The magnitude of PHE adsorption capacity followed the order of MP-HPB>MP-HTAB>MP-TBAB>RP, ranged from 924 to 1,228 ?g g(-1). A negative trend between adsorption capacity (y) and (O+N)/C ratio of biosorbent (x) was observed (y = -1,369.6x + 2,176), which confirmed the negative effect of polarity on polycyclic aromatic hydrocarbon (PAH) removal. The study provides a guide to modify raw materials to enhance adsorption of hydrophobic organics. PMID:22766871

Zhou, Y B; Chen, L; Wang, X Q; Xu, Y X; Lu, J

2012-01-01

126

Biotreatment on cellulose fluff pulp: quaternary ammonium salts finish and grafting with beta-cyclodextrin.  

PubMed

For its potential performances to be expanded, cellulose needs to be processed in different ways. Therefore, an object of the present work was to provide a chemical modification of cellulose through: a specific finish with two quaternary ammonium salts (namely Aliquat 336 and Aliquat 1529, respectively). Chemical grafting of beta-cyclodextrin derivative (beta-CD) onto fibers followed by the inclusion of benzoic acid in the grafted CD cavities as a probe chemical. Physicochemical properties and performances of the untreated and treated fibers have been determined with infrared spectra, microscopy, swelling measurements, antimicrobial finishing tests, and dye adsorption. Our results show that cellulose fibers can be efficiently modified with no significant changes in its structural and surface properties; the treated fibers show an attractive behavior in swelling, dye adsorption and antibacterial activity. PMID:19089647

Ghemati, Djamila; Oudia, Atika; Aliouche, Djamel; Lamouri, Saad

2008-12-17

127

New class of quaternary ammonium salts, derivatives of methyl D-glucopyranosides.  

PubMed

Reactions of two aromatic and two aliphatic amines with methyl 6-O-p-toluenesulfonyl-alpha-D-glucopyranoside or methyl 6-O-p-toluenesulfonyl-beta-D-glucopyranoside were performed on a micro-scale. The synthesis and preparative isolation methods have been developed for quaternary N-(methyl 2,3,4-tri-O-acetyl-6-deoxy-alpha- and -beta-D-glucopyranoside-6-yl)ammonium salts derived from three amines: trimethylamine, 2-methylpyridine, and pyridine. The reaction products were examined with 1H, 13C NMR spectroscopy. N-(Methyl 2,3,4-tri-O-acetyl-6-deoxy-beta-d-glucopyranoside-6-yl)trimethylammonium tosylate was additionally analyzed with X-ray crystallography. PMID:15178398

Pellowska-Januszek, Lucyna; Dmochowska, Barbara; Skorupa, Eugenia; Chojnacki, Jaros?aw; Wojnowski, Wies?aw; Wi?niewski, Andrzej

2004-06-01

128

Disinfection of Water with Quaternary Ammonium Salts Insolubilized on a Porous Glass Surface  

PubMed Central

Insoluble quaternary ammonium salts bound to porous glass showed antibacterial activity. An agent designated as G12, which had a dodecyl alkyl chain, was selected for some antibacterial tests on comparison of it with the agent reported previously. The antibacterial activity of G12 toward Escherichia coli was mainly due to the adsorption of cells and therefore gradually decreased during continuous treatment of a cell suspension. The lost G12 activity was completely recovered by washing with ethanol, and the activity of refreshed G12 decreased in the same manner as that of fresh G12. The lost activity was, however, always recovered only by ethanol treatment. This indicated that G12 might interact with cells more strongly by means of a hydrophobic force than an electrostatic one. The antimicrobial spectrum showed that G12 was effective against not only bacteria but also yeasts.

Nakagawa, Yoshihiro; Hayashi, Hiroyuki; Tawaratani, Takahiko; Kourai, Hiroki; Horie, Tokunaru; Shibasaki, Isao

1984-01-01

129

Perfluorinated quaternary ammonium salts of polyoxometalate anions: Fluorous biphasic oxidation catalysis with and without fluorous solvents  

SciTech Connect

Perfluorinated quaternary ammonium cations, [CF{sub 3}(CF{sub 2}){sub 7}(CH{sub 2}){sub 3}]{sub 3}CH{sub 3}N{sup +} (RFN{sup +}), were synthesized and used as counter cations for the [WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW{sub 9}O{sub 34}){sub 2}]{sup 12-} (M = Mn(II), Zn(II)), polyoxometalate. The (RFN{sup +}){sub 12}[WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW9O{sub 34}){sub 2}] compounds were fluorous biphasic catalysts for alcohol and alkenol oxidation, and alkene epoxidation with aqueous hydrogen peroxide. Reaction protocols with or without a fluorous solvent were tested. The catalytic activity and selectivity was affected both by the hydrophobicity of the solvent and the substrate.

Maayan, Galia; Fish, Richard H.; Neumann, Ronny

2003-05-28

130

Quaternary ammonium silane-functionalized, methacrylate resin composition with antimicrobial activities and self-repair potential  

PubMed Central

Design of antimicrobial polymers for enhancing healthcare issues and minimizing environmental problems is an important endeavor with both fundamental and practical implications. Quaternary ammonium silane-functionalized methacrylate (QAMS) represents an example of antimicrobial macromonomers synthesized by a sol-gel chemical route; these compounds possess flexible Si-O-Si bonds. In present work, a partially-hydrolyzed QAMS copolymerized with bis-GMA is introduced. This methacrylate resin was shown to possess desirable mechanical properties with both a high degree of conversion and minimal polymerization shrinkage. Kill-on-contact microbiocidal activities of this resin were demonstrated using single-species biofilms of Streptococcus mutans (ATCC 36558), Actinomyces naeslundii (ATCC 12104) and Candida albicans (ATCC 90028). Improved mechanical properties after hydration provided the proof-of-concept that QAMS-incorporated resin exhibits self-repair potential via water-induced condensation of organic modified silicate (ormosil) phases within the polymerized resin matrix.

Gong, Shi-qiang; Niu, Li-na; Kemp, Lisa K.; Yiu, Cynthia K.Y.; Ryou, Heonjune; Qi, Yi-pin; Blizzard, John D.; Nikonov, Sergey; Brackett, Martha G.; Messer, Regina L.W.; Wu, Christine D.; Mao, Jing; Brister, L. Bryan; Rueggeberg, Frederick A.; Arola, Dwayne D.; Pashley, David H.; Tay, Franklin R.

2012-01-01

131

Heme Binding Contributes to Antimalarial Activity of Bis-Quaternary Ammoniums  

PubMed Central

Quaternary ammonium compounds have received recent attention due to their potent in vivo antimalarial activity based on their ability to inhibit de novo phosphatidylcholine synthesis. Here we show that in addition to this, heme binding significantly contributes to the antimalarial activity of these compounds. For the study, we used a recently synthesized bis-quaternary ammonium compound, T16 (1,12-dodecanemethylene bis[4-methyl-5-ethylthiazolium] diodide), which exhibits potent antimalarial activity (50% inhibitory concentration, ?25 nM). Accumulation assays reveal that this compound is readily concentrated several hundredfold (cellular accumulation ratio, ?500) into parasitized erythrocytes. Approximately 80% of the drug was shown to be distributed within the parasite, ?50% of which was located in the parasite food vacuoles. T16 uptake was affected by anion substitution (permeation increasing in the order Cl? < Br? = NO3? < I? < SCN?) and was sensitive to furosemide—properties similar to substrates of the induced new permeability pathway in infected erythrocytes. Scatchard plot analysis of in situ T16 binding revealed high-affinity and low-affinity binding sites. The high-affinity binding site Kd was similar to that measured in vitro for T16 and ferriprotoporphyrin IX (FPIX) binding. Significantly, the capacity but not the Kd of the high-affinity binding site was decreased by reducing the concentration of parasite FPIX. Decreasing the parasite FPIX pool also caused a marked antagonism of T16 antimalarial activity. In addition, T16 was also observed to associate with parasite hemozoin. Binding of T16 to FPIX in the digestive food vacuole is shown to be critical for drug accumulation and antimalarial activity. These data provide additional new mechanisms of antimalarial activity for this promising new class of antimalarial compounds.

Biagini, Giancarlo A.; Richier, Eric; Bray, Patrick G.; Calas, Michele; Vial, Henri; Ward, Stephen A.

2003-01-01

132

Surface structures of PDMS incorporated with quaternary ammonium salts designed for antibiofouling and fouling release applications.  

PubMed

Poly(dimethylsiloxane) (PDMS) materials have been extensively shown to function as excellent fouling-release (FR) coatings in the marine environment. The incorporation of biocide moieties, such as quaternary ammonium salts (QAS), can impart additional antibiofouling properties to PDMS-based FR coating systems. In this study, the molecular surface structures of two different types of QAS-incorporated PDMS systems were investigated in different chemical environments using sum frequency generation vibrational spectroscopy (SFG). Specifically, a series of PDMS coatings containing either a QAS with a single ammonium salt group per molecule or a quaternary ammonium-functionalized polyhedral oligomeric silsesquioxane (Q-POSS) were measured with SFG in air, water, and artificial seawater (ASW) to investigate the relationships between the interfacial surface structures of these materials and their antifouling properties. Although previous studies have shown that the above-mentioned materials are promising contact-active antifouling coatings, slight variations of the QAS structure can lead to substantial differences in the antifouling performance. Indeed, the SFG results presented here indicated that the surface structures of these materials depend on several factors, such as the extent of quaternization, the molecular weight of the PDMS component, and the functional groups of the QAS used for incorporation into the PDMS matrix. It was concluded that in aqueous environments a lower extent of Q-POSS quaternization and the use of ethoxy (instead of methoxy) functional groups for QAS incorporation facilitated the extension of the alkyl chains away from the nitrogen atom of the QAS on the surface. The SFG results correlated well with the antifouling activity studies that indicated that the coatings exhibiting a lower concentration of longer alkyl chains protruding out of the surface can neutralize microorganisms more effectively, ultimately leading to better antifouling performance. Furthermore, the results of this study provide additional evidence that incorporated QAS exert their antimicrobial activity through a two-step interaction. The first step is the adsorption of the bacteria on the surface as a result of the electrostatic attraction between the negatively charged microorganisms and the positively charged QAS nitrogen atoms on the surface. The second step is the disruption of the cell membranes by the penetration of the QAS long, extended alkyl chains. PMID:23394402

Liu, Yuwei; Leng, Chuan; Chisholm, Bret; Stafslien, Shane; Majumdar, Partha; Chen, Zhan

2013-02-25

133

Coal cleaning employing quaternary salts. Annual report, July 1, 1984-June 30, 1985. [Tetrabutyl ammonium hydroxide; tetramethyl ammonium hydroxide  

SciTech Connect

An investigation into a novel approach to coal desulfurization has been initiated. This approach is in the formative stages, but is envisioned to included a treatment step to swell coal in quaternary salt solution followed by physical separation, chemical reaction to desulfurize the coal, and recovery of the quaternary salt. The present program was aimed at developing fundamental data associated with the first step. This report covers the first six months of the project. The objective of this portion of the program was to define conditions under which complete exchange of quaternary salts with coal hydroxy groups occurs, define the extent of coal swelling and changes in coal properties as a function of amount of exchange, and determine the effect of process variation on swelling rate and coal properties. Results of this research have demonstrated that substantial coal swelling occurs in the presence of quaternary salts. The amount of quaternary exchange is a small portion of the total OH groups present in the coal. Swelling has been found to be dependent on the concentration of quaternary salts, the ratio of solution to coal, time of exchange, and the type of solvent. The data also demonstrate that particle size and size distribution are changed extensively by the quaternary salt treatment. Furthermore, it appears that iron sulfide and/or sulfate are dissolved in the quaternary base. Also, some organic material is dissolved by the quaternary base. Preliminary data indicate that minerals and inertinite can be concentrated after quaternary salt treatment. The results indicate that quaternary recovery should be easier than first expected. Also, the excessive swelling with little exchange indicated that the surface chemistry of the coal is altered after exchange. Thus, oil agglomeration and froth flotation should be improved when coals are treated with the quaternary salt. 11 refs., 11 tabs.

Hippo, E.J.; Murdie, N.

1985-09-01

134

Synthesis and DNA threading properties of quaternary ammonium [Ru(phen)2(dppz)]2+ derivatives.  

PubMed

Ruthenium complexes with one dipyrido[3,2-a:2'-3'-c]phenazine (dppz) ligand, e.g. [Ru(phen)(2)(dppz)](2+) (phen=phenanthroline), shows strong binding to double helical DNA and are well-known DNA "light-switch" molecules. We have here investigated four new [Ru(phen)(2)(dppz)](2+) derivatives with different bulky quaternary ammonium substituents on the dppz ligand to find relationships between molecular structure and intercalation kinetics, which is considered to be of importance for antitumor applicability. Linear dichroism spectroscopy shows that the enantiomers of the new complexes exhibit very similar binding geometries (intercalation of dppz moiety between adjacent DNA base pairs) as the enantiomers of the parent [Ru(phen)(2)(dppz)](2+) complex. Absorption spectra and luminescence properties provide further evidence for a final intercalative binding mode which has to be reached by threading of a bulky moiety between the strands of the DNA. Delta-enantiomers of all the new complexes show much slower association and dissociation kinetics than that of a reference complex without a cationic substituent. Kinetics were not very different whether the bulky quaternary group was derived from hexamethylene tetramine or 1,4-diazabicyclo-(2,2,2)octane (DABCO) or whether it had one or two positive charges. However, a complex in which the hexamethylene tetramine substituent is attached via a phenyl group showed a lowered association rate, in addition to an improved quantum yield of luminescence. A second positive charge on the DABCO substituent resulted in a much slower dissociation rate, suggesting that the distance from the Ru-centre and the amount of charge are both important for threading intercalation kinetics. PMID:19467711

Li, Minna; Lincoln, Per

2009-04-23

135

Isolation and characterization of heterotrophic bacteria able to grow aerobically with quaternary ammonium alcohols as sole source of carbon and nitrogen  

Microsoft Academic Search

The quaternary ammonium alcohols (QAAs) 2,3-dihydroxypropyl-trimethyl-ammonium (TM), dimethyl-diethanol-ammonium (DM) and methyl-triethanol-ammonium (MM) are hydrolysis products of their parent esterquat surfactants, which are widely used as softeners in fabric care. We isolated several bacteria growing with QAAs as the sole source of carbon and nitrogen. The strains were compared with a previously isolated TM-degrading bacterium, which was identified as a representative

Andres Kaech; Nathalie Vallotton; Thomas Egli

2005-01-01

136

The inhibitive effect of some quaternary ammonium salts towards corrosion of aluminium in hydrochloric acid solution  

NASA Astrophysics Data System (ADS)

The inhibitive action of some quaternary ammonium salts towards the corrosion of aluminium in hydrochloric acid was tested by thermometric, mass loss and polarization measurements. Parallelism between the different methods was established. It is suggested that the tested compounds act as cathodic inhibitors. The inhibitors appear to function through adsorption, following the Temkin adsorption isotherm. The values of free energy of adsorption have been calculated and discussed. The inhibitor character of the additives depends upon the concentration as well as the composition of the inhibitor. Within the given homolegous series the contribution of the functional group to adsorption increases with the length of the chain. The aim of this article is to throw some light on the mechanism of inhibition of these bulky molecules on the corrosion of aluminium in hydrochloric acid. L'action inhibitrice de certains sels d'ammonium quaternaires vis-à-vis de la corrosion de l'aluminium dans l'acide chlorhydrique en solution a été testée par des mesures thermiques de perte de matière et de polarisation. Il est suggéré que les composés testés agissent comme des inhibiteurs cathodiques, fonctionnant par adsorption suivant l'isotherme de Temkin. Les énergies libres d'adsorption ont été calculées et discutées. Le caractère inhibiteur des additifs dépend aussi bien de leur concentration que de leur composition. Pour une série d'inhibiteurs homologues, la contribution à l'adsorption du groupe fonctionnel augmente avec la longueur de la chaîne. Le but de cet article est de mieux comprendre le mécanisme d'inhibition de ces grosses molécules sur la corrosion de l'aluminium dans l'acide chlorhydrique.

Mohamed, A.-M. K.; Al-Nadjm, A.; Fouda, A.-A. S.

1998-10-01

137

The Nature of Excess Intercalation of a Quaternary Ammonium Compound in Smectite Clay  

NASA Astrophysics Data System (ADS)

Particular clay minerals, such as the French green clay used by Brunet de Courssou in the treatment of Mycobacterium ulcerans, have intrinsic antibacterial properties that surpass those of most conventional antibiotic treatments. The antimicrobial properties of the French green clay, comprised of 24% Fe-illite and 50% Fe-smectite, have been reproduced by a synthetically generated organically modified smectite (organoclay). The quaternary ammonium compound hexadecyl-trimethyl ammonium bromide (HDTMA) must undergo a cation exchange process in excess of the calculated cation exchange capacity (CEC) to render the clay antimicrobial. This work explores the position of the excess bonding within the clay lattice so as to challenge the hydrophobic bonding hypothesis proposed by Zhao et al (2003) concerning excess intercalation. After determining the CEC of BP smectite, organoclays were produced containing concentrations of one, two, and three times the CEC of HDTMA. Powder X-ray diffraction (PXRD) on a scale of 2 to 20 degrees 2theta was conducted on each of the three organoclays to infer the loading capacity of the smectite by means of the clay’s d-spacing as a proxy for expansion. Liquid Chromatography/Mass Spectrometry (LC-MS) quantitatively determined the surfactant retained on the clay by measuring the residual HDTMA in solution after extracting the organoclay. The d-spacing of the three organoclays implied that the first CEC of HDTMA entered the interlayer as an anion by means of a cation exchange process while the second and third CEC were incorporated into the clay lattice by means of a “hydrophobic bonding” mechanism in which the excess surfactants formed associations with the counterion Br+. Fourier transform infrared (FT-IR) spectra will be collected to determine the specific attachment of the excess bonding within the clay structure.

Lafer, D. A.; Giese, R.

2010-12-01

138

Superhydrophobic cotton fabric coating based on a complex layer of silica nanoparticles and perfluorooctylated quaternary ammonium silane coupling agent  

NASA Astrophysics Data System (ADS)

A superhydrophobic complex coating for cotton fabrics based on silica nanoparticles and perfluorooctylated quaternary ammonium silane coupling agent (PFSC) was reported in this article. The complex thin film was prepared through a sol-gel process using cotton fabrics as a substrate. Silica nanoparticles in the coating made the textile surface much rougher, and perfluorooctylated quaternary ammonium silane coupling agent on the top layer of the surface lowered the surface free energy. Textiles coated with this coating showed excellent water repellent property, and water contact angle (CA) increased from 133° on cotton fabrics treated with pure PFSC without silica sol pretreatment up to 145°. The oil repellency was also improved and the contact angle of CH 2I 2 droplet on the fabric surface reached to 131°. In contrast, the contact angle of CH 2I 2 on the fabric surface treated with pure PFSC was only 125°.

Yu, Minghua; Gu, Guotuan; Meng, Wei-Dong; Qing, Feng-Ling

2007-01-01

139

Cyano-containing quaternary ammonium-based ionic liquid as a ‘co-solvent’ for lithium battery electrolyte  

Microsoft Academic Search

Imidazolium-based ionic liquid is one of attractive candidates for advanced lithium battery electrolyte. However, its cathodic stability is not sufficient for the reversible charge–discharge of negative electrodes. The authors previously proposed a quaternary ammonium-based ionic liquid containing a cyano group (cyano-QA) as a film-forming electrolyte on the negative electrode surface. In the present study, several cyano-QA ionic liquids have been

Minato Egashira; Maika Nakagawa; Izumi Watanabe; Shigeto Okada; Jun-ichi Yamaki

2005-01-01

140

Discovery of novel quaternary ammonium derivatives of (3R)-quinuclidinyl carbamates as potent and long acting muscarinic antagonists.  

PubMed

Novel quaternary ammonium derivatives of N,N-disubstituted (3R)-quinuclidinyl carbamates have been identified as potent M(3) muscarinic antagonists with long duration of action in an in vivo model of bronchoconstriction. These compounds have also presented a high level of metabolic transformation (human liver microsomes). The synthesis, structure-activity relationships and biological evaluation of these compounds are reported. PMID:21524581

Prat, Maria; Buil, María Antonia; Fernández, Maria Dolors; Castro, Jordi; Monleón, Juan Manuel; Tort, Laia; Casals, Gaspar; Ferrer, Manuel; Huerta, Josep Maria; Espinosa, Sònia; López, Manuel; Segarra, Victor; Gavaldà, Amadeu; Miralpeix, Montserrat; Ramos, Israel; Vilella, Dolors; González, Marisa; Córdoba, Mònica; Cárdenas, Alvaro; Antón, Francisca; Beleta, Jorge; Ryder, Hamish

2011-04-03

141

Synthesis of Novel Organic-Inorganic Self-Organized Compounds Containing Quaternary Ammonium Ions and its Structural Characterization  

Microsoft Academic Search

Organic-inorganic layered perovskite compounds described by (RNH 3 ) 2 MX 4 [R: alkyl group, M: divalent metals, X: halogen] were reported to form self-organized quantum-well structures. In this study, we aimed to synthesize novel organic-inorganic self-organized compounds with quaternary ammonium ions instead of primary alkylammonium ions. New compounds, [(C 12 H 25 ) 2 (CH 3 ) 2 N]PbBr

Satoshi Kano; Kenjiro Teshima; Masahiro Rikukawa; Kohei Sanui

2002-01-01

142

Properties and Preparation of Chitosan\\/Silanol Quaternary Ammonium Modified Silica Hybrids Using Sol–Gel Process  

Microsoft Academic Search

Chitosan\\/modified silica nanocomposites, with a sol–gel process being used to prepare a silanol quaternary ammonium modified silica possessing antimicrobial activity, were investigated, as well as the thermal properties, morphology, optical, mechanical, antimicrobial, and adsorption properties of this type of nanocomposite. Grafting of the modifier onto nanosilica was confirmed through the Fourier transform infrared (FTIR) spectra. X-ray diffraction patterns indicated that

S.-M. Lai; W.-C. Chen; Tai-Wei Wu; Arthur J.-M. Yang; C.-H. Yang

2011-01-01

143

The Properties and preparation of Chitosan\\/silanol quaternary ammonium modified silica hybrids using sol-gel PROCESS  

Microsoft Academic Search

Chitosan\\/modified silica nanocomposites, with a sol-gel process being used to prepare a silanol quaternary ammonium modified silica possessing antimicrobial activity, were investigated, as well as the thermal properties, morphology, optical, mechanical, antimicrobial, and adsorption properties of this type of nanocomposite. Grafting of the modifier onto nanosilica was confirmed through the Fourier transform infrared (FTIR) spectra. X-ray diffraction patterns indicated the

S.-M. Lai; W.-C. Chen; Tai-Wei Wu; Arthur J.-M. Yang; C.-H. Yang

2011-01-01

144

Corrosion inhibition of iron in acidic solutions by alkyl quaternary ammonium halides: Correlation between inhibition efficiency and molecular structure  

Microsoft Academic Search

The corrosion inhibition of iron in 0.5M H2SO4 solutions by alkyl quaternary ammonium halides (AQAH) inhibitors has been studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. The correlation between inhibition efficiency and molecular structure of the AQAH compounds is investigated. The results show that besides the concentration, the structure of alkyl groups and the type of halide

Lin Niu; Hu Zhang; Fenghua Wei; Suxiang Wu; Xiaoli Cao; Pengpeng Liu

2005-01-01

145

Determination of selected quaternary ammonium compounds by liquid chromatography with mass spectrometry. Part II. Application to sediment and sludge samples in Austria  

Microsoft Academic Search

Soxhlet extraction and high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry detection (MS\\/MS) was used for the determination of selected quaternary ammonium compounds (QACs) in solid samples. The method was applied for the determination of alkyl benzyl, dialkyl and trialkyl quaternary ammonium compounds in sediment and sludge samples in Austria. The overall method quantification limits range from 0.6 to

Elena Martínez-Carballo; Carmen González-Barreiro; Andrea Sitka; Norbert Kreuzinger; Sigrid Scharf; Oliver Gans

2007-01-01

146

Comparison of physicochemical properties of new ionic liquids based on imidazolium, quaternary ammonium, and guanidinium cations.  

PubMed

More than 50 ionic liquids were prepared by using imidazolium, quaternary ammonium, and guanidinium cations and various anions. In these series, different cationic structures such as 1-benzyl-3-methylimidazolium [Bzmim]+, 1,3-dibenzylimidazolium [BzmiBz]+, 1-octyl-3-methylimidazolium [C8mim]+, 1-decyl-3-methylimidazolium [C10mim]+, tricapryl-methylammonium [Aliquat]+, benzyltriethylammonium [BzTEA]+, phenyltrimethylammonium [PhTMA]+, and dimethyldihexylguanidinium [DMG]+ were combined with anions, p-toluenesulfonate [TSA](-), dicyanoamide [DCA]-, saccharine (2-sulfobenzoic acid imide sodium salt) [SAC]-, trifluoroacetate [TFA]-, bis(trifluoromethanesulfonyl)imide [Tf2N]-, trifluoromethanesulfonate [TfO]-, and thiocyanate [SCN]-. Important physical data for these ionic liquids are collated, namely solubility in common solvents, viscosity, density, melting point and water content. Apart from the viscosity, the Newtonian and non-Newtonian behavior of these ionic liquids is also disclosed. Stability of these ionic liquids under thermal, basic, acidic, nucleophilic, and oxidative conditions was also studied. The features of the solid-liquid phase transition were analyzed, namely the glass transition temperature and the heat capacity jump associated with the transition from the non-equilibrium glass to the metastable supercooled liquid. A degradation temperature of each ionic liquid was also determined. Comparisons of the properties of various ionic liquids were made. PMID:17665379

Kulkarni, Prashant S; Branco, Luís C; Crespo, João G; Nunes, M Cristiana; Raymundo, Anabela; Afonso, Carlos A M

2007-01-01

147

Mitochondrial dysfunction is the focus of quaternary ammonium surfactant toxicity to mammalian epithelial cells.  

PubMed

Surfactants have long been known to have microbicidal action and have been extensively used as antiseptics and disinfectants for a variety of general hygiene and clinical purposes. Among surfactants, quaternary ammonium compounds (QAC) are known to be the most useful antiseptics and disinfectants. However, our previous toxicological studies showed that QAC are also the most toxic surfactants for mammalian cells. An understanding of the mechanisms that underlie QAC toxicity is a crucial first step in their rational use and in the design and development of more effective and safer molecules. We show that QAC-induced toxicity is mediated primarily through mitochondrial dysfunction in mammalian columnar epithelial cell cultures in vitro. Toxic effects begin at sublethal concentrations and are characterized by mitochondrial fragmentation accompanied by decreased cellular energy charge. At very low concentrations, several QAC act on mitochondrial bioenergetics through a common mechanism of action, primarily by inhibiting mitochondrial respiration initiated at complex I and, to a lesser extent, by slowing down coupled ADP phosphorylation. The result is a reduction of cellular energy charge which, when reduced below 50% of its original value, induces apoptosis. The lethal effects are shown to be primarily a result of this process. At higher doses (closer to the critical micellar concentration), QAC induce the complete breakdown of cellular energy charge and necrotic cell death. PMID:23529737

Inácio, Ângela S; Costa, Gabriel N; Domingues, Neuza S; Santos, Maria S; Moreno, António J M; Vaz, Winchil L C; Vieira, Otília V

2013-03-25

148

Effects of the quaternary ammonium compound OX-572 on ventricular tachyarrhythmias complicating acute myocardial infarction.  

PubMed

Patients with acute myocardial infarction who developed defined ventricular tachyarrhythmias were randomly allocated to two groups. The patients (n=34) in one of the groups received the quaternary ammonium compound N,N-bis (phenylcarbamoylmethyl) dimethylammoniumchloride (QX-572) intravenously as an infusion of 8 mg/kg body weight over 30 minutes. The patients in the other group (n=33) received saline and acted as controls. The analysis of arrhythmias was based on a continuous electrocardiogram recorded in parallel to routine monitoring during the 24 hours after the start of infusion. Only the detection of ventricular tachycardia or the development of ventricular fibrillation on routine monitoring could induce a change in antiarrhythmic treatment. The incidence of patients with ventricular tachycardia recorded was significantly lower in the QX-572 group (38%) than in the control group (73%). About half the number of patients with ventricular tachycardia recorded on the continuous electrocardiogram were also detected by means of routine monitoring. The number of patients with various types of ventricular premature contractions (1-5/min, greater than 5/min, paired, multifocal, R on T), ventricular tachycardia, and rapid idioventricular rhythm were compared within successive one-hour periods. For all types of ventricular tachyarrhythmias except rapid idioventricular rhythm there was a lower incidence of arrhythmias in the QX-572 group... PMID:1125119

Rydén, L; Hjalmarson, A; Waldenström, A

1975-04-01

149

Effects of the quaternary ammonium compound OX-572 on ventricular tachyarrhythmias complicating acute myocardial infarction.  

PubMed Central

Patients with acute myocardial infarction who developed defined ventricular tachyarrhythmias were randomly allocated to two groups. The patients (n=34) in one of the groups received the quaternary ammonium compound N,N-bis (phenylcarbamoylmethyl) dimethylammoniumchloride (QX-572) intravenously as an infusion of 8 mg/kg body weight over 30 minutes. The patients in the other group (n=33) received saline and acted as controls. The analysis of arrhythmias was based on a continuous electrocardiogram recorded in parallel to routine monitoring during the 24 hours after the start of infusion. Only the detection of ventricular tachycardia or the development of ventricular fibrillation on routine monitoring could induce a change in antiarrhythmic treatment. The incidence of patients with ventricular tachycardia recorded was significantly lower in the QX-572 group (38%) than in the control group (73%). About half the number of patients with ventricular tachycardia recorded on the continuous electrocardiogram were also detected by means of routine monitoring. The number of patients with various types of ventricular premature contractions (1-5/min, greater than 5/min, paired, multifocal, R on T), ventricular tachycardia, and rapid idioventricular rhythm were compared within successive one-hour periods. For all types of ventricular tachyarrhythmias except rapid idioventricular rhythm there was a lower incidence of arrhythmias in the QX-572 group...

Ryden, L; Hjalmarson, A; Waldenstrom, A

1975-01-01

150

Preparation and characterization of montmorillonite modified by phosphorus-nitrogen containing quaternary ammonium salts  

NASA Astrophysics Data System (ADS)

A novel class of phosphorous-nitrogen containing quaternary ammonium salts (PNQAS) were synthesized and used as modifiers for sodium montmorillonite (Na-MMT). Montmorillonites modified by PNQAS (PNQAS-MMT) were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dispersibility measurement and thermogravimetric analysis (TGA). The results show that the PNQAS have been intercalated into the montmorillonite layers successfully and the basal spacing of PNQAS-MMT is 1.70-2.65 nm. The XRD results show that the basal spacing of PNQAS-MMT reaches a maximum when PNQAS/CEC molar ratio is above 1.2. The increase of chain length of PNQAS is beneficial to expand the interlayer space of the MMT. The TEM and dispersibility measurement results show that PNQAS-MMT have stronger hydrophobicity and better dispersion than Na-MMT. The TGA results reveal that the thermal stability for PNQAS-MMT is affected by the structure and composition of intercalated PNQAS cations. The Tinital of PNQAS-MMT is between 286 °C and 385 °C, which can be applied to the modification of the polymer as a halogen-free flame retardant.

Huang, Guobo; Gao, Jianrong; Wang, Xu

2012-02-01

151

The Inhibitory Effects of Quaternary Ammonium Methacrylates on Soluble and Matrix-bound MMPs  

PubMed Central

Matrix metalloproteinases (MMPs) bound to dentin contribute to the progressive degradation of collagen fibrils in hybrid layers created by dentin adhesives. This study evaluated the MMP-inhibiting potential of quaternary ammonium methacrylates (QAMs), with soluble rhMMP-9 and a matrix-bound endogenous MMP model. Six different QAMs were initially screened by a rhMMP-9 colorimetric assay. For the matrix-bound endogenous MMPs, we aged demineralized dentin beams for 30 days in calcium- and zinc-containing media (CM; control), chlorhexidine, or QAMs in CM to determine the changes in dry mass loss and solubilization of collagen peptides against baseline levels. The inhibitory effects of QAMs on soluble rhMMP-9 varied between 34 and 100%. Beams incubated in CM showed a 29% decrease in dry mass (p < 0.05), whereas beams incubated with QAMs showed only 0.2%-6% loss of dry mass. Significantly more solubilized collagen was detected from beams incubated in CM (p < 0.05). It is concluded that QAMs exhibited dentin MMP inhibition comparable with that of chlorhexidine, but required higher concentrations.

Tezvergil-Mutluay, A.; Agee, K.A.; Uchiyama, T.; Imazato, S.; Mutluay, M.M.; Cadenaro, M.; Breschi, L.; Nishitani, Y.; Tay, F.R.; Pashley, D.H.

2011-01-01

152

CO2 capture from simulated fuel gas mixtures using semiclathrate hydrates formed by quaternary ammonium salts.  

PubMed

In order to investigate the feasibility of semiclathrate hydrate-based precombustion CO2 capture, thermodynamic, kinetic, and spectroscopic studies were undertaken on the semiclathrate hydrates formed from a fuel gas mixture of H2 (60%) + CO2 (40%) in the presence of quaternary ammonium salts (QASs) such as tetra-n-butylammonium bromide (TBAB) and fluoride (TBAF). The inclusion of QASs demonstrated significantly stabilized hydrate dissociation conditions. This effect was greater for TBAF than TBAB. However, due to the presence of dodecahedral cages that are partially filled with water molecules, TBAF showed a relatively lower gas uptake than TBAB. From the stability condition measurements and compositional analyses, it was found that with only one step of semiclathrate hydrate formation with the fuel gas mixture from the IGCC plants, 95% CO2 can be enriched in the semiclathrate hydrate phase at room temperature. The enclathration of both CO2 and H2 in the cages of the QAS semiclathrate hydrates and the structural transition that results from the inclusion of QASs were confirmed through Raman and (1)H NMR measurements. The experimental results obtained in this study provide the physicochemical background required for understanding selective partitioning and distributions of guest gases in the QAS semiclathrate hydrates and for investigating the feasibility of a semiclathrate hydrate-based precombustion CO2 capture process. PMID:23718261

Park, Sungwon; Lee, Seungmin; Lee, Youngjun; Seo, Yongwon

2013-06-11

153

Degradation of imidazolium- and quaternary ammonium-functionalized poly(fluorenyl ether ketone sulfone) anion exchange membranes.  

PubMed

Imidazolium and quaternary ammonium-functionalized poly(fluorenyl ether ketone sulfone)s were synthesized successfully with the same degree of cationic functionalization and identical polymer backbones for a comparative study of anion exchange membranes (AEMs) for solid-state alkaline membrane fuel cells (AMFCs). Both anion exchange membranes were synthesized using a new methyl-containing monomer that avoided the use of toxic chloromethylation reagents. The polymer chemical structures were confirmed by ¹H NMR and FTIR. The derived AEMs were fully characterized by water uptake, anion conductivity, stability under aqueous basic conditions, and thermal stability. Interestingly, both the cationic groups and the polymer backbone were found to be degraded in 1 M NaOH solution at 60 °C over 48 h as measured by changes of ion exchange capacity and intrinsic viscosity. Imidazolium-functionalized poly(fluorenyl ether ketone sulfone)s had similar aqueous alkaline stability to quaternary ammonium-functionalized materials at 60 °C but much lower stability at 80 °C. This work demonstrates that quaternary ammonium and imidazolium cationic groups are not stable on poly(arylene ether sulfone) backbones under relatively mild conditions. Additionally, the poly(arylene ether sulfone) backbone, which is one of the most common polymers used in ion exchange membrane applications, is not stable in the types of molecular configurations analyzed. PMID:23067022

Chen, Dongyang; Hickner, Michael A

2012-11-01

154

Selectivity Control in Synergistic Liquid-Liquid Anion Exchange of Univalent Anions via Structure-Specific Cooperativity between Quaternary Ammonium Cations and Anion Receptors  

SciTech Connect

Two anion receptors enhance liquid-liquid anion exchange when added to quaternary alkylammonium chloride anion exchangers, but with a striking dependence upon the structure of the alkylammonium cation. Two anion receptors were investigated, meso-octamethylcalix[4]pyrrole (C4P) and the bisthiourea tweezer 1,1'-(propane-1,3-diyl)bis(3-(4-sec-butylphenyl)thiourea (BTU). C4P has the unique ability in its cone anion-binding conformation to accept an appropriately sized electropositive species in the resulting cup formed by its four electron-rich pyrrole groups, while BTU is not expected to be predisposed for a specific host-guest interaction with the quaternary ammonium cations. It was therefore hypothesized that synergism between C4P and methyltri(C8,10)alkylammonium chloride (Aliquat 336) would be uniquely pronounced owing to insertion of the methyl group of the Aliquat cation into the C4P cup, and we present herein data supporting this expectation. While synergism is comparatively weak for both exchangers with the BTU receptor, synergism between C4P and Aliquat 336 is indeed so strong that anion exchange prefers chloride over more extractable nitrate and trifluoroacetate, effectively overcoming the ubiquitous Hofmeister bias. A thermochemical analysis of synergistic anion exchange has been provided for the first time, unraveling the observed selectivity behavior and resulting in the estimation of binding constants for C4P with the ion pairs of A336+ with Cl , Br , OAcF3 , NO3 , and I . The uniquely strong positive cooperativity between A336 and C4P underscores the advantage of a supramolecular approach in the design of synergistic anion exchange systems.

Borman, Christopher J [ORNL; Bonnesen, Peter V [ORNL; Moyer, Bruce A [ORNL

2012-01-01

155

Tin-catalyzed efficient conversion of carbohydrates for the production of 5-hydroxymethylfurfural in the presence of quaternary ammonium salts.  

PubMed

An efficient and tin-catalyzed production of 5-hydroxymethyl furfural (5-HMF) from carbohydrates is reported. The efficient conversion of glucose has been investigated using the combination of SnCl4 and different quaternary ammonium salts. It was found that tetrabutyl ammonium bromide (TBAB) was able to efficiently promote conversion of glucose to 5-HMF in the presence of SnCl4. For instance, a 69.1% yield of 5-HMF was obtained with SnCl4-tetrabutyl ammonium bromide (SnCl4-TBAB) system in DMSO for 2h at 100°C in air. The effects of catalyst amount, reaction time, and reaction temperature were investigated in detail. Furthermore, the SnCl4-TBAB was also employed to the conversion of fructose, sucrose, inulin, starch, and cellulose. The competitive results were obtained under mild conditions. PMID:23435168

Tian, Guo; Tong, Xinli; Cheng, Yi; Xue, Song

2013-01-30

156

Salt matrix voltammetry: Microphase redox processes at ammonium chloride | gold | gas triple phase boundaries  

Microsoft Academic Search

Electrochemical processes at the electrode | ammonium chloride salt crystal | gas triple phase boundary are detected under the condition that (i) microscopic contact points of salt crystals to a suitable working electrode are formed and (ii) the relative humidity level is adjusted to allow sufficient surface ion conduction in a thin water film within the salt matrix. In this

Sara E. C. Dale; Charles Y. Cummings; Frank Marken

2011-01-01

157

THE EFFECTIVENESS OF ORAL AMMONIUM CHLORIDE ON INCREASED EXCRETION OF RADIOSTRONTIUM IN MAN  

Microsoft Academic Search

The effectiveness of oral ammonium chloride as an agent capable of ; decreasing body retention of radiostrontium was examined. Strontium-85 was used ; in these experiments because it is considerably less hazardous than Sr⁹°. ; Both isotopes share a similar metabolic pattern of behavior. Two patients were ; studied. One was a 61 year old negro (Patient A) who had

M. L. Charles; D. Laszlo

1959-01-01

158

Kinetics of emulsion copolymerization of (2-methacryloyloxyethyl) trimethyl ammonium chloride and acrylamide with gamma rays  

Microsoft Academic Search

Inverse emulsion copolymerization of (2-methacryloyloxyethyl) trimethyl ammonium chloride with acrylamide has been studied with gamma ray dilatometrically. Aqueous monomer solutions were emulsified in kerosene with a blend of two surfactants (Span80 and OP10). The gel effect is evident from the increase of the molecular weight with conversion and also from the percentage conversion versus time curves. Monomer reactivity ratios have

Ge Xuewu; Ye Qiang; Xu Xiangling; Zhang Zhicheng; Sun Qian

1997-01-01

159

A SANS study for structural transition of micelles of cationic octadecyl trimethyl ammonium chloride and anionic ammonium dodecyl sulfate surfactants in aqueous solutions  

Microsoft Academic Search

The sizes and structures of micelles formed in aqueous solutions of cationic octadecyl trimethyl ammonium chloride (OTAC) and anionic ammonium dodecyl sulfate (ADS) surfactants were investigated using small angle neutron scattering (SANS). For aqueous OTAC solutions, SANS data indicate that the structure of micelles is of sphere with core and hydrated shell up to OTAC 50mM. As the total OTAC

Kye-Hong Kang; Kyung-Hee Lim

160

Comparing effectiveness of rhamnolipid biosurfactant with a quaternary ammonium salt surfactant for hydrate anti-agglomeration.  

PubMed

Natural gas is projected to be the premium fuel of the 21st century because of availability, as well as economical and environmental considerations. Natural gas is coproduced with water from the subsurface forming gas hydrates. Hydrate formation may result in shutdown of onshore and offshore operations. Industry practice has been usage of alcohols--which have undesirable environmental impacts--to affect bulk-phase properties and inhibit hydrate formation. An alternative to alcohols is changing the surface properties through usage of polymers and surfactants, effective at 0.5-3 wt % of coproduced water. One group of low-dosage hydrate inhibitors (LDHI) are kinetic inhibitors, which affect nucleation rate and growth. A second group of LDHI are anti-agglomerants, which prevent agglomeration of small hydrate crystallites. Despite great potential, reported work on hydrate anti-agglomeration is very limited. In this paper, our focus is on the use of two vastly different surfactants as anti-agglomerants. We use a model oil, water, and tetrahydrofuran as a hydrate-forming species. We examine the effectiveness of a quaternary ammonium salt (i.e., quat). Visual observation measurements show that a small concentration of the quat (0.01%) can prevent agglomeration. However, a quat is not a green chemical and therefore may be undesirable. We show that a rhamnolipid biosurfactant can be effective to a concentration of 0.05 wt %. One difference between the two surfactants is the stability of the water-in-oil emulsions created. The biosurfactant forms a less stable emulsion, which makes it very desirable for hydrate application. PMID:18171051

York, J Dalton; Firoozabadi, Abbas

2008-01-03

161

Effectiveness of sanitation with quaternary ammonium compound or chlorine on stainless steel and other domestic food-preparation surfaces.  

PubMed

The relative ability of various materials used for domestic and/or food-service sinks and countertops to be sanitized was determined. Both smooth (unused) and abraded surfaces were tested by exposure to 200 mg of quaternary ammonium compound per liter or 200 mg of sodium hypochlorite per liter. Surface materials tested included mechanically polished (type 304, #4 finish) and electropolished stainless steel, polycarbonate, and mineral resin. Surfaces were prepared for testing by allowing attachment of a Staphylococcus aureus culture for 4 h to achieve an initial attached population of 10(4) to 10(5) CFU/cm2. The test procedure involved immersion of the surface in sanitizer solution followed by wiping with a sanitizer-saturated cloth. Residual staphylococci were detected by overlaying agar directly on the treated surface. Results indicated that the stainless steels and the smooth polycarbonate, which had 0.5 log CFU/cm2 or fewer of residual staphylococci, were more readily sanitized by quaternary ammonium compound than were either the mineral resin surfaces, which had nearly 2.0 log CFU/cm2 of residual staphylococci, or the abraded polycarbonate which had nearly 1.0 log CFU/cm2 of residual staphylococci. Chlorine was most effective on the mechanically polished stainless steel, the unabraded electropolished stainless steel, and the polycarbonate surfaces, reducing cell populations to less than 1.0 log CFU/cm2. Chlorine was less effective on abraded electropolished stainless steel and mineral resin surfaces, where populations remained greater than 1.0 log CFU/cm2. Sanitation with quaternary ammonium compound or chlorine reduced S. aureus populations more than 1,000-fold on all surfaces except unabraded mineral resin. PMID:10465039

Frank, J F; Chmielewski, R A

1997-01-01

162

Corrosion inhibition of iron in acidic solutions by alkyl quaternary ammonium halides: Correlation between inhibition efficiency and molecular structure  

NASA Astrophysics Data System (ADS)

The corrosion inhibition of iron in 0.5 M H2SO4 solutions by alkyl quaternary ammonium halides (AQAH) inhibitors has been studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. The correlation between inhibition efficiency and molecular structure of the AQAH compounds is investigated. The results show that besides the concentration, the structure of alkyl groups and the type of halide ions of these AQAH inhibitors greatly influence the inhibition efficiency. Data obtained from EIS measurements are analyzed to model the corrosion inhibition process through appropriate equivalent circuit models.

Niu, Lin; Zhang, Hu; Wei, Fenghua; Wu, Suxiang; Cao, Xiaoli; Liu, Pengpeng

2005-12-01

163

Reversible Swelling of Chitosan and Quaternary Ammonium Modified Chitosan Brush Layers: Effect of pH and Counter Anion Size and Functionality  

PubMed Central

This study investigates the swelling of grafted polycationic brushes as a function of pH and anion type. The brushes are chitosan (CH) and chitosans with 27% and 51% degree of substitution (DS) of quaternary ammonium salt, denoted as CH-Q25 and CH-Q50, respectively. The water content and swelling behaviors are monitored using in situ quartz-crystal microbalance with dissipation (QCM-D). The pH varies from ~3.5 to 8.5, and the counter anion types include chloride, acetate, and citrate. At fixed pH, the water content and brush swelling increase as the DS increases. Whereas the CH-Q50 brush layer shows symmetric swelling with a minimum near pH = 4.5, the swelling of CH and CH-Q25 is relatively constant as pH decreases from 8.2 to 5.5, and then begins to increase near pH 4. These studies indicate that the symmetric swelling of CH-Q50 is likely attributed to increasing protonation of primary amines for pH values below pH 6.5 and the quaternary ammonium salts above pH 6.5. At pH 4, the swelling of the CH brush increases upon exchanging the smaller chloridewith a bulkier acetate anion, which is less effective at screening intra/inter molecular repulsion. In contrast, upon exchanging the acetate with trifunctional citrate, CH and CH-Q25 brushes collapse by 53 and 42%, respectively, because the citrate forms ionic cross-links. To test antibacterial properties, silicon oxide, CH and CH-Q50 brush layers are exposed to 107–108 cfu/ml of S. aureus for two days at 37 °C and exposed to stepped shear stresses in 2 min intervals. Whereas an S. aureus biofilm adheres strongly to silicon oxide and CH for stresses up to 12 dyne/cm2, biofilms on CH-Q50 detach at a relatively low shear stress, 1.5 dyne/cm2. Due to their high degree of swelling that can be tuned via pH, counterion size and type, chitosan and quaternary modified chitosans have potential as responsive coatings for applications including MEMS/NEMS devices and drug eluting implants.

Lee, Hyun-Su; Yee, Michael Q.; Eckmann, Yonaton Y.; Hickok, Noreen J.; Eckmann, David M.; Composto, Russell J.

2012-01-01

164

Water Soluble Copolymers. 57. Amphiphilic Cyclocopolymers of Diallylalkoxybenzylmethylammonium Chloride and Diallyldimethyl- Ammonium Chloride.  

National Technical Information Service (NTIS)

Water-soluble cyclocopolymers of N,N-diallyl-N-alkoxybenzyl- N-methylammonium chloride (alkyl = hexyl and octyl) and N,N-diallyl-N,N-dimethylammonium chloride were prepared by free radical polymerization at 50 deg C in aqueous solution. The copolymer comp...

Y. Chang C. L. McCormick

1994-01-01

165

The Competition of Charge Remote and Charge Directed Fragmentation Mechanisms in Quaternary Ammonium Salt Derivatized Peptides—An Isotopic Exchange Study  

NASA Astrophysics Data System (ADS)

Derivatization of peptides as quaternary ammonium salts (QAS) is a promising method for sensitive detection by electrospray ionization tandem mass spectrometry (Cydzik et al. J. Pept. Sci. 2011, 17, 445 -453). The peptides derivatized by QAS at their N-termini undergo fragmentation according to the two competing mechanisms - charge remote (ChR) and charge directed (ChD). The absence of mobile proton in the quaternary salt ion results in ChR dissociation of a peptide bond. However, Hofmann elimination of quaternary salt creates an ion with one mobile proton leading to the ChD fragmentation. The experiments on the quaternary ammonium salts with deuterated N-alkyl groups or amide NH bonds revealed that QAS derivatized peptides dissociate according to the mixed ChR-ChD mechanism. The isotopic labeling allows differentiation of fragments formed according to ChR and ChD mechanisms.

Cydzik, Marzena; Rudowska, Magdalena; Stefanowicz, Piotr; Szewczuk, Zbigniew

2011-12-01

166

Interactions of bovine serum albumin with cationic imidazolium and quaternary ammonium gemini surfactants: effects of surfactant architecture.  

PubMed

The interactions of BSA with a series of cationic imidazolium gemini surfactants ([C(n)-s-C(n)im]Br(2), n=10, 12, 14, s=2, 4, 6), quaternary ammonium surfactants (C(12)C(2)C(12)), and their corresponding monomers ([C(12)mim]Br and DTAB) are investigated by fluorescence using pyrene as a molecular probe, synchronous fluorescence, circular dichroism (CD), and UV-visible absorption spectra. These surfactants are used to elucidate the effects of surfactant hydrophilic head group, spacer length, and hydrophobic chain length on the conformation of BSA. The results of fluorescence spectra and CD show that the imidazolium gemini surfactants with shorter spacers or with longer hydrophobic chains have a larger effect on BSA unfolding, and the imidazolium gemini surfactant interacts with BSA more strongly than its corresponding monomer and the quaternary ammonium gemini surfactant. These conclusions have been confirmed by the binding constants (K(a)) and binding sites (n) for the BSA/surfactant system. Stern-Volmer quenching constants K(SV) of cationic surfactants binding to BSA are obtained, indicating that the probable quenching mechanism is initiated by ground-state complex formation rather than by dynamic collision. Moreover, the synchronous fluorescence spectra show that the surfactants mainly interact with tryptophan residues of BSA. PMID:23044272

Zhou, Ting; Ao, Mingqi; Xu, Guiying; Liu, Teng; Zhang, Juan

2012-09-19

167

Erythrocyte lysis in isotonic solution of ammonium chloride: theoretical modeling and experimental verification.  

PubMed

A mathematical model of erythrocyte lysis in isotonic solution of ammonium chloride is presented in frames of a statistical approach. The model is used to evaluate several parameters of mature erythrocytes (volume, surface area, hemoglobin concentration, number of anionic exchangers on membrane, elasticity and critical tension of membrane) through their sphering and lysis measured by a scanning flow cytometer (SFC). SFC allows measuring the light-scattering pattern (indicatrix) of an individual cell over the angular range from 10 degrees to 60 degrees . Comparison of the experimentally measured and theoretically calculated light scattering patterns allows discrimination of spherical from non-spherical erythrocytes and evaluation of volume and hemoglobin concentration for individual spherical cells. Three different processes were applied for erythrocytes sphering: (1) colloid osmotic lysis in isotonic solution of ammonium chloride, (2) isovolumetric sphering in the presence of sodium dodecyl sulphate and albumin in neutrally buffered isotonic saline, and (3) osmotic fragility test in hypotonic media. For the hemolysis in ammonium chloride, the evolution of distributions of sphered erythrocytes on volume and hemoglobin content was monitored in real-time experiments. The analysis of experimental data was performed in the context of a statistical approach, taking into account that parameters of erythrocytes vary from cell to cell. PMID:18083194

Chernyshev, Andrey V; Tarasov, Peter A; Semianov, Konstantin A; Nekrasov, Vyacheslav M; Hoekstra, Alfons G; Maltsev, Valeri P

2007-10-22

168

A one-pot synthesis of functionalized thiazoles from acid chlorides, secondary amines, ethyl bromopyruvate, and ammonium thiocyanate.  

PubMed

An efficient one-pot synthesis of ethyl 2-(4-aryl-2-dialkylamino-1,3-thiazole-5-yl)-2-oxoacetates using acid chlorides, secondary amines, ethyl bromopyruvate, and ammonium thiocyanate is described. PMID:19205915

Yavari, Issa; Hossaini, Zinatossadat; Sabbaghan, Maryam; Ghazanfarpour-Darjani, Majid

2009-02-10

169

A one-pot synthesis of functionalized thiazoles from acid chlorides, secondary amines, ethyl bromopyruvate, and ammonium thiocyanate  

Microsoft Academic Search

An efficient one-pot synthesis of ethyl 2-(4-aryl-2-dialkylamino-1,3-thiazole-5-yl)-2-oxoacetates using acid chlorides, secondary\\u000a amines, ethyl bromopyruvate, and ammonium thiocyanate is described.

Issa Yavari; Zinatossadat Hossaini; Maryam Sabbaghan; Majid Ghazanfarpour-Darjani

2009-01-01

170

The Solubility Polytherm in the Ammonium Chloride - Urea - Water Ternary System (Politerma Troinoi System Khlorid Ammonia - Mochevnya - Voda).  

National Technical Information Service (NTIS)

In the present work the authors established that urea forms a complex compound with water and ammonium chloride. The latter salt is in itself a complex compound. Phase and solubility polytherm diagrams are included.

N. N. Kitrova

1973-01-01

171

A Systematic Investigation of Quaternary Ammonium Ions as Asymmetric Phase Transfer Catalysts. Synthesis of Catalyst Libraries and Evaluation of Catalyst Activity  

PubMed Central

Despite over three decades of research into asymmetric phase transfer catalysis (APTC), a fundamental understanding of the factors that affect the rate and stereoselectivity of this important process are still obscure. This paper describes the initial stages of a long-term program aimed at elucidating the physical organic foundations of APTC employing a chemoinformatic analysis of the alkylation of a protected glycine imine with a libraries of enantiomerically enriched quaternary ammonium ions. The synthesis of the quaternary ammonium ions follows a diversity oriented approach wherein the tandem inter[4+2]/intra[3+2] cycloaddition of nitroalkenes serves as the key transformation. A two part synthetic strategy comprised of: (1) preparation of enantioenriched scaffolds and (2) development of parallel synthesis procedures is described. The strategy allows for the facile introduction of four variable groups in the vicinity of a stereogenic quaternary ammonium ion. The quaternary ammonium ions exhibited a wide range of activity and to a lesser degree enantioselectivity. Catalyst activity and selectivity are rationalized in a qualitative way based on the effective positive potential of the ammonium ion.

Denmark, Scott E.; Gould, Nathan D.; Wolf, Larry M.

2011-01-01

172

Effect of quaternary ammonium salts on carrier-mediated transport of lanthanide ions through cellulose triacetate membranes  

SciTech Connect

Fluxes of all lanthanides, except promethium, across cellulose triacetate membranes were determined by using mixtures of o-nitrophenyl n-octyl ether and quaternary ammonium salts as plasticizers, and 4-benzoyl-3-methyl-1-phenyl-5-pyrazolone (BMPP) and 4-trifluoroacetyl-3-methyl-1-phenyl-5-pyrazolone (TMPP) as carriers. The quaternary ammonium salts used were didodecyldimethyl-, distearyldimethyl-, tetrahexyl-, tetraoctyl-, and tetradecylammonium bromides [referred to as (C{sub 12}){sub 2}NBr, (C{sub 18}){sub 2}NBr, (C{sub 6}){sub 4}NBr, (C{sub 8}){sub 4}NBr, and (C{sub 10}){sub 4}NBr, respectively]. The effect of these ammonium bromides on the flux was demonstrated. For membranes containing 0.1 M (C{sub 12}){sub 2}NBr and (C{sub 18}){sub 2}NBr, BMPP exhibited considerably high fluxes. The fluxes of lanthanum and cerium using BMPP for (C{sub 12}){sub 2}NBr were higher than those of the other lanthanides. For the membranes containing 0.5 M (C{sub 12}){sub 2}NBr and 0.1 M (C{sub 18}){sub 2}NBr, however, no difference in flux among the lanthanides was observed. The fluxes using TMPP for (C{sub 12}){sub 2}NBr and (C{sub 18}){sub 2}NBr were very small, with the exception of some lanthanides. Appreciably high fluxes were observed for membranes containing 0.1 M (C{sub 6}){sub 4}NBr using BMPP. For (C{sub 8}){sub 4}NBr and (C{sub 10}){sub 4}NBr, BMPP exhibited low fluxes. For these membranes using TMPP, the lanthanides were scarcely transported. 13 refs., 5 figs., 2 tabs.

Sugiura, M. [National Chemical Lab. for Industry, Ibaraki (Japan)

1993-05-01

173

Numerical modelling of chloride propagation in the quaternary aquifer of the southern Upper Rhine Graben  

NASA Astrophysics Data System (ADS)

The deep groundwater in the quaternary gravel sequence of the southern Upper Rhine Graben locally contains high chloride concentrations near the river Rhine between Fessenheim (France) in the South and Breisach (Germany) in the North. This historical pollution is mainly due to past infiltration from the former brine storage basins of the French potash mines on the “Fessenheim Island” and—to a lesser extent—from the leaching of the salt dumps of the German potash mines in Buggingen and Heitersheim. The spreading of the salt plume was investigated by means of a groundwater model. The aim of the model was to understand the brine movement, the present distribution of chloride as defined by recent hydrochemical investigations, and to select locations for new reconnaissance boreholes. The geological structure was reproduced by a three layer model, which was calibrated for steady state flow conditions. The hydraulic conductivity of the first layer was determined by comparing measured and calculated heads in the model area. The vertical resolution was refined to simulate the density-dependent salt transport processes. The transport of the salt plumes was simulated over a 40-year period, starting at the beginning of brine storage in the 1950s. The relevant transport parameters have been estimated in a sensitivity analysis, where the simulated breakthrough curves of chloride concentration have been compared with the measured data. The results of the groundwater model indicate that brines containing approximately 1 million tons of chloride are still present at the bottom of the aquifer. These highly concentrated salt brines mix with fresh water from the upper part of the aquifer. This dispersive process leads to the formation of a plume of chloride-rich water extending downstream, where pumping wells for several local water supplies are located.

Lang, U.; Gudera, T.; Elsass, P.; Wirsing, G.

2005-09-01

174

Effects of Freezing, Drying, Ultraviolet Irradiation, Chlorine, and Quaternary Ammonium Treatments on the Infectivity of Myxospores of Myxobolus cerebralis for Tubifex tubifex  

Microsoft Academic Search

The effects of freezing, drying, ultraviolet irradiation (UV), chlorine, and a quaternary ammonium compound on the infectivity of the myxospore stage of Myxobolus cerebralis (the causative agent of whirling disease) for Tubifex tubifex were examined in a series of laboratory trials. Freezing at either ?20°C or ?80°C for a period of 7 d or 2 months eliminated infectivity as assessed

Ronald P. Hedrick; Terry S. McDowell; Kaveramma Mukkatira; Elizabeth MacConnell; Brian Petri

2008-01-01

175

Selective Production of Electrostatically-Bound Adducts of Alkyl Cations/Polyoxoanions by the Collision-Induced Fragmentations of Their Quaternary Ammonium Counterparts  

NASA Astrophysics Data System (ADS)

Solutions of the quaternary ammonium salts of a set of classic polyoxometalates (POMs) (Keggin [XM12O40]n-, Dawson [P2W18O62]6-, and Lindqvist [M6O19]2- (X = P, Si; M = W, Mo) were characterized by electrospray mass spectrometry. The gas-phase fragmentations of a series of quaternary ammonium-associated clusters were investigated by their collision-induced dissociations to elucidate their fragmentation mechanisms. It was found that the quaternary ammonium-associated clusters had distinctive dissociation characteristics. Moreover, the mono-quaternary ammonium-associated clusters, {NR4[POMs]}(n-1)-, shared a common fragmentation feature, that is, they decomposed exclusively into their respective alkyl cation-bound clusters irrespective of the different cation sizes and the different natures of the polyoxoanions. The optimized geometries and the binding energies of the mono cation-bound Lindqvist POM-based clusters were obtained by calculations. To the best of our knowledge, this is the first investigation of the gas-phase fragmentations of these noncovalent complexes between organic amines and inorganic POM anions by a combination of theory and mass spectrometry.

Cao, Jie; Xu, Chong; Fan, YanXuan; Fan, LinYuan; Zhang, XiuHui; Hu, ChangWen

2013-06-01

176

Selective production of electrostatically-bound adducts of alkyl cations/polyoxoanions by the collision-induced fragmentations of their quaternary ammonium counterparts.  

PubMed

Solutions of the quaternary ammonium salts of a set of classic polyoxometalates (POMs) (Keggin [XM12O40](n-), Dawson [P2W18O62](6-), and Lindqvist [M6O19](2-) (X = P, Si; M = W, Mo) were characterized by electrospray mass spectrometry. The gas-phase fragmentations of a series of quaternary ammonium-associated clusters were investigated by their collision-induced dissociations to elucidate their fragmentation mechanisms. It was found that the quaternary ammonium-associated clusters had distinctive dissociation characteristics. Moreover, the mono-quaternary ammonium-associated clusters, {NR4[POMs]}((n-1)-), shared a common fragmentation feature, that is, they decomposed exclusively into their respective alkyl cation-bound clusters irrespective of the different cation sizes and the different natures of the polyoxoanions. The optimized geometries and the binding energies of the mono cation-bound Lindqvist POM-based clusters were obtained by calculations. To the best of our knowledge, this is the first investigation of the gas-phase fragmentations of these noncovalent complexes between organic amines and inorganic POM anions by a combination of theory and mass spectrometry. PMID:23595257

Cao, Jie; Xu, Chong; Fan, YanXuan; Fan, LinYuan; Zhang, XiuHui; Hu, ChangWen

2013-04-18

177

Adsorption microcalorimetry used to study interfacial aggregation of quaternary ammonium surfactants (zwitterionic and cationic) on powdered silica supports in dilute aqueous solutions  

Microsoft Academic Search

Titration microcalorimetry has been used to compare interfacial aggregation of some zwitterionic and cationic quaternary ammonium surfactants on powdered silica substrates with micellisation in free aqueous solution. Enthalpy of dilution measurements allowed determining the molar enthalpies of micellisation for two zwitterionic amphiphiles, (dodecyldimethylammonio)butanoate and (dodecyl dimethylammonio)-1-propanesulfonate, and two cationics, benzyldimethyldodecylammonium bromide (BDDAB) and tetradecyltrimethylammonium bromide (TTAB). The effect of temperature

Jerzy Zajac

2000-01-01

178

Quaternary Ammonium Salts from Hydrolyzed Fatty Oil Based on Novel Tertiary Amines Used as Corrosion Inhibitors for Pipelines Carbon Steel at Acid Job in Petroleum Industry  

Microsoft Academic Search

Ten new quaternary ammonium salts (QASs) were designed and synthesized from hydrolyzed fatty oils; the hydrolyzed oils were used as a source of alkyl halides to prepare the QASs by refluxing the fatty alkyl halide with ethoxylated amines as untraditional 3° amines in acetone. The structure of the prepared QASs were characterized by FTIR and H NMR spectroscopy. The prepared

A. M. Al-Sabagh; N. G. Kandile; Nahed Amer; Omaima Ramadan; E. A. Khamis

2012-01-01

179

A universal fixation method based on quaternary ammonium salts (RNAlater) for omics-technologies: Saccharomyces cerevisiae as a case study.  

PubMed

Genomics, transcriptomics, proteomics and fluxomics are powerful omics-technologies that play a major role in today's research. For each of these techniques good sample quality is crucial. Major factors contributing to the quality of a sample is the actual sampling procedure itself and the way the sample is stored directly after sampling. It has already been described that RNAlater can be used to store tissues and cells in a way that the RNA quality and quantity are preserved. In this paper, we demonstrate that quaternary ammonium salts (RNAlater) are also suitable to preserve and store samples from Saccharomyces cerevisiae for later use with the four major omics-technologies. Moreover, it is shown that RNAlater also preserves the cell morphology and the potential to recover growth, permitting microscopic analysis and yeast cell culturing at a later stage. PMID:23417260

van Eijsden, Rudy G E; Stassen, Catherine; Daenen, Luk; Van Mulders, Sebastiaan E; Bapat, Prashant M; Siewers, Verena; Goossens, Katty V Y; Nielsen, Jens; Delvaux, Freddy R; Van Hummelen, Paul; Devreese, Bart; Willaert, Ronnie G

2013-02-16

180

Effect of temperature on critical micelle concentration and thermodynamic potentials of micellization of anionic ammonium dodecyl sulfate and cationic octadecyl trimethyl ammonium chloride  

Microsoft Academic Search

The critical micelle concentrations (CMCs) of anionic ammonium dodecyl sulfate (ADS) and cationic octadecyltrimethylammonium chloride (OTAC) were determined at various temperatures using a du Noüy ring tensiometer. The CMC decreased to a certain minimum and then increased with the temperature, displaying a U-shaped behavior. This behavior was analyzed using a power-law equation on the basis of reduced variables. The exponents

Kye-Hong Kang; Hong-Un Kim; Kyung-Hee Lim

2001-01-01

181

1H NMR observation of the critical slowing down in ammonium chloride  

NASA Astrophysics Data System (ADS)

We have studied the ? transition in ammonium chloride (NH4Cl) by means of 1H NMR. In previous reports, the 1H NMR spin-lattice relaxation time (T1) did not show the critical slowing down, whereas the Cl35 NMR spin-lattice relaxation time revealed a sharp ? transition at the critical temperature. Our measurements of the 1H solid echo decay constant (T2E) and the second moment near the critical temperature manifest the critical slowing down, and the temperature dependence of the T2E is well explained by the dynamic Ising model.

Lee, K. W.; Lee, C. H.; Lee, C. E.; Kang, J. K.

1995-12-01

182

Antioxidant Potential of Momordica Charantia in Ammonium Chloride-Induced Hyperammonemic Rats  

PubMed Central

The present study was aimed to investigate the antioxidant potential of Momordica charantia fruit extract (MCE) in ammonium chloride-induced (AC) hyperammonemic rats. Experimental hyperammonemia was induced in adult male Wistar rats (180–200?g) by intraperitoneal injections of ammonium chloride (100?mg?kg?1 body weight) thrice a week. The effect of oral administration (thrice a week for 8 consecutive weeks) of MCE (300?mg?kg?1 body weight) on blood ammonia, plasma urea, serum liver marker enzymes and oxidative stress biomarkers in normal and experimental animals was analyzed. Hyperammonemic rats showed a significant increase in the activities of thiobarbituric acid reactive substances, hydroperoxides and liver markers (alanine transaminase, aspartate transaminase and alkaline phosphatase), and the levels of glutathione peroxidase, superoxide dismutase, catalase and reduced glutathione were decreased in the liver and brain tissues. Treatment with MCE normalized the above-mentioned changes in hyperammonemic rats by reversing the oxidant-antioxidant imbalance during AC-induced hyperammonemia, and offered protection against hyperammonemia. Our results indicate that MCE exerting the antioxidant potentials and maintaining the cellular integrity of the liver tissue could offer protection against AC-induced hyperammonemia. However, the exact underlying mechanism is yet to be investigated, and examination of the efficacy of the active constituents of the M. charantia on hyperammonemia is desirable.

Thenmozhi, A. Justin; Subramanian, P.

2011-01-01

183

Synthesis of aryl alkyl ethers by alkylation of phenols with quaternary ammonium salts.  

PubMed

Phenolic compounds can be efficiently O-methylated with tetramethylammonium chloride in diglyme or polyethyleneglycol (PEG) at temperatures of 150-160 °C and in the presence of either K2CO3 or NaOH. When applying benzyltrimethylammonium chloride as a reagent, the benzylation and methylation of phenols occurs, with the benzylation product always predominating. With allyl-substituted phenols as substrates and using NaOH as a base it was possible to achieve both the alkylation and the double-bond isomerization of the allyl group to obtain (E/Z)-propenyl-substituted methyl and benzyl aryl ethers in a single preparative step. PMID:24061652

Maraš, Nenad; Polanc, Slovenko; Ko?evar, Marijan

2010-03-01

184

Occurrence of and a possible mechanism for resistance to a quaternary ammonium compound in Listeria monocytogenes  

Microsoft Academic Search

In a study of 200 Listeria monocytogenes isolates, 10% were determined to be resistant to benzalkonium chloride (BC). Serial subcultivation of initially BC sensitive (BCS) and BC resistant (BCR) isolates in sublethal concentrations of BC resulted in enhanced and approximately equal resistance of all strains to the compound. Fifty per cent of the BCR isolates showed resistance to ethidium bromide

Brit Aase; Gunhild Sundheim; Solveig Langsrud; Liv Marit Rørvik

2000-01-01

185

New quaternary ammonium camphor derivatives and their antiviral activity, genotoxic effects and cytotoxicity.  

PubMed

The synthesis and biological evaluation of a novel series of dimeric camphor derivatives are described. The resulting compounds were studied for their antiviral activity, cyto- and genotoxicity. Compounds 3a and 3d in which the quaternary nitrogen atoms are separated by the C5H10 and ?9H18 aliphatic chain, exhibited the highest efficiency as an agent inhibiting the reproduction of the influenza virus A(H1N1)pdm09. The cytotoxicity data of compounds 3 and 4 revealed their moderate activity against malignant cell lines; compound 3f had the highest activity for the CEM-13 cells. These results show close agreement with the data of independent studies on toxicity of these compounds, in particular that the toxicity of compounds strongly depends on spacer length. PMID:23993669

Sokolova, Anastasiya S; Yarovaya, Capital O Cyrilliclga I; Shernyukov, Capital A Cyrillicndrey V; Pokrovsky, Capital Em Cyrillicichail A; Pokrovsky, Capital A Cyrillicndrey G; Lavrinenko, Valentina A; Zarubaev, Vladimir V; Tretiak, Tatiana S; Anfimov, Pavel M; Kiselev, Oleg I; Beklemishev, Anatoly B; Salakhutdinov, Nariman F

2013-08-12

186

Liquid–liquid–solid equilibria for the quaternary system water+ethanol+1-pentanol+sodium chloride at 25°C  

Microsoft Academic Search

Salting-out effect can be used to improve the extraction of some solutes by modifying the solute distribution between two liquid phases. In this work we report the results obtained for the quaternary system water+ethanol+1-pentanol+sodium chloride at 25°C. All equilibrium regions (one liquid, two liquids, one liquid+one solid and two liquids+one solid zones) have been systematically studied. Tie lines and tie-triangles

M. M. Olaya; A. Botella; A. Marcilla

1999-01-01

187

Prediction and measurement of mild steel corrosion inhibition by alkyl pyridinium chloride and alkyl trimethyl ammonium bromide surfactants in acidic chloride media  

Microsoft Academic Search

Surfactants are important corrosion inhibitors that are used in different applications. This paper utilizes the recently developed methodology and formulae to predict mild steel corrosion inhibition by alkyl pyridinium chloride and alkyl trimethyl ammonium bromide compounds. By utilizing different surfactants of varying chain lengths in different acidic media and determining the associated corrosion inhibition, the relationship between surfactant concentration, surfactant

WanLin Wang; Michael L. Free

2003-01-01

188

Preliminary projections of the effects of chloride-control structures on the Quaternary aquifer at Great Salt Plains, Oklahoma  

USGS Publications Warehouse

About 1,200 tons of chloride per day are added to the salt load of the Salt Fork of the Arkansas River at Great Salt Plains Lake from natural sources. The source of this chloride is brine discharge from the rocks of Permian age in the vicinity of the lake. The U.S. Army Corps of Engineers has planned a chloride-control project. The Corps requested that the U.S. Geological Survey use a digital model to project the effects of the chloride-control plan on ground water. Ground-water flow and ground-water transport models were calibrated to represent the Quaternary aquifer that is the near-surface part of the flow system. The models were used to project the effects of planned chloride-control structures. Based on model results, ground-water levels are projected to rise as much as 19 feet. However, these water-level rises will occur only in areas near three reservoirs. Changes in ground-water level caused by the project will be small throughout most of the area. Chloride concentration of ground water is projected to increase by more than 90,000 milligrams per liter at one location. However, significant increases in chloride concentration during the 50-year period simulated are projected to be limited to areas where the ground water already contains excessive chloride concentrations.

Reed, J. E.

1982-01-01

189

Synthesis of bis-quaternary ammonium peroxotungstates (peroxomolybdates) and their catalytic activity in oxidation of alcohols by aqueous H 2 O 2  

Microsoft Academic Search

Three kinds of bis-quaternary ammonium salts of peroxotungstate and peroxomolybdate, such as PhCH2N-(CH2)6NCH2Ph[W(O2)4] 2H2O, PhCH2N(CH2)6NCH2Ph[W-O(O2)2(C2O4)] and PhCH2N(CH2)6NCH2Ph[MoO(O2)2(C2O4)], have been synthesized and characterized. Their catalytic activity in the oxidation of cyclohexanol and benzyl alcohol\\u000a was investigated with only aqueous 30% hydrogen peroxide. The results show that the bis-quaternary ammonium peroxotungstates\\u000a are excellent catalysts in the oxidation of benzyl alcohol and cyclohexanol

Xianying Shi; Junfa Wei

2007-01-01

190

Separation of aromatic carboxylic acids using quaternary ammonium salts on reversed-phase HPLC. 1. Separation behavior of aromatic carboxylic acids  

SciTech Connect

In order to develop separation processes and analytical methods for aromatic carboxylic acids for the coal oxidation products, the separation behavior of aromatic carboxylic acids on a reversed-phase HPLC using eluent containing quaternary ammonium salt has been investigated. The retention mechanism of aromatic carboxylic acids was discussed on the basis of both ion-pair partition model and ion-exchange model. The retention behavior of aromatic carboxylic acids possessing one (or two) carboxylic acid group(s) followed the ion-pair partition model, where linear free energy relationship was observed between the capacity factor and the extraction equilibrium constants of benzoic acid and naphthalene carboxylic acid. Besides, the retention behavior followed ion-exchange model with increasing the number of carboxylic acids, where the capacity factor of benzene polycarboxylic acids is proportional to the association constants between aromatic acids and quaternary ammonium ions calculated on the basis of an electrostatic interaction model.

Kawamura, K.; Okuwaki, A.; Verheyen, T.; Perry, G.J. [Tohoku University, Miyagi (Japan). Graduate School of Environmental Studies

2006-02-15

191

Heterogeneous freezing of ammonium sulfate and sodium chloride solutions by long chain alcohols  

NASA Astrophysics Data System (ADS)

High molecular weight organic compounds emitted during biomass burning can be transported to high altitudes where they may affect ice processes through heterogeneous nucleation. We show that freezing of solutions of ammonium sulfate and sodium chloride catalyzed by long chain alcohols is roughly consistent with the hypothesis that the water activity at the mean freezing temperature is a constant offset from the water activity at the melting point of the solution, though films of the longer chain alcohols may undergo structural changes at higher salt concentrations which cause a deviation from the constant offset. The heterogeneous nucleation rate coefficient, averaged over all solutions, alcohols, and droplet sizes is 6.0 × 104 +/- 4.0 × 104 cm-2 s-1, with no dependence on any of those parameters.

Cantrell, Will; Robinson, Carly

2006-04-01

192

REMOVAL OF RADIOSTRONTIUM IN MAN BY ORALLY ADMINISTERED AMMONIUM CHLORIDE TWO WEEKS AFTER EXPOSURE: THE EFFECT OF LOW AND HIGH CALCIUM INTAKE  

Microsoft Academic Search

The removal of radiostrontium was studied in man by means of orally ; administered ammonium chloride during low and high calcium intake both at the ; time of the injection of the Sr⁸⁵ tracer and two weeks thereafter. During ; low calcium intake, orally administered ammonium chloride was as effective in ; removing radiostrontium two weeks after administration of the

H. Spencer; J. Samachson

1961-01-01

193

Separation of aromatic carboxylic acids using quaternary ammonium salts on reversed-phase HPLC. 2. Application for the analysis of Loy Yang coal oxidation products  

SciTech Connect

In order to develop separation processes and analytical methods for aromatic carboxylic acids for the coal oxidation products, the separation behavior of aromatic carboxylic acids on a reversed-phase HPLC using eluent containing quaternary ammonium salt was optimized using the solvent gradient method. This method was applied for the analysis of Loy Yang coal oxidation products. It was confirmed that the analytical data using this method were consistent with those determined using gas chromatography.

Kawamura, K.; Okuwaki, A.; Verheyen, T.V.; Perry, G.J. [Tohoku University, Miyagi (Japan). Graduate School of Environmental Studies

2006-07-01

194

Combinatorial materials research applied to the development of new surface coatings IX: An investigation of novel antifouling\\/fouling-release coatings containing quaternary ammonium salt groups  

Microsoft Academic Search

Polysiloxane coatings containing chemically-bound (''tethered'') quaternary ammonium salt (QAS) moieties were investigated for potential application as environmental-friendly coatings to control marine biofouling. A combinatorial\\/ high-throughput approach was applied to the investigation to enable multiple variables to be probed simultaneously and efficiently. The variables investigated for the moisture-curable coatings included QAS composition, ie alkyl chain length, and concentration as well as

Partha Majumdar; Elizabeth Lee; Nehal Patel; Kaley Ward; Shane J. Stafslien; Justin Daniels; Bret J. Chisholm; Philip Boudjouk; Maureen E. Callow; James A. Callow; Stephanie E. M. Thompson

2008-01-01

195

Determination of alkyl benzyl and dialkyl dimethyl quaternary ammonium biocides in occupational hygiene and environmental media by liquid chromatography with electrospray ionisation mass spectrometry and tandem mass spectrometry  

Microsoft Academic Search

A new method for the simultaneous qualitative and quantitative determination of alkyl benzyl and dialkyl quaternary ammonium compounds (QACs) has been developed. Analysis is by reversed-phase high-performance liquid chromatography coupled with electrospray ionisation mass spectrometry. QACs are extremely amenable to the electrospray ionisation technique (limit of detection of BAC C12 homologue 3 ng ml?1). The selectivity of mass spectrometric detection

Michael J Ford; Lee W Tetler; John White; Duncan Rimmer

2002-01-01

196

Design and synthesis of imidazole and triazole derivatives as Lp-PLA? inhibitors and the unexpected discovery of highly potent quaternary ammonium salts.  

PubMed

New Lp-PLA(2) inhibitors were synthesized by the bioisosteric replacement of the amide group of Darapladib with an imidazole or a triazole. Unfortunately, the inhibitory activities of these derivatives were lower than that of Darapladib. But interestingly, a series of quaternary ammonium salts that were isolated as by-products during this synthetic work were found with high potency. Of these by-products, compound 22c showed a similar profile to Darapladib both in vitro and in vivo. PMID:23385210

Wang, Kai; Xu, Wenwei; Liu, Yang; Zhang, Wei; Wang, Wenyi; Shen, Jianhua; Wang, Yiping

2013-01-16

197

Determination of selected quaternary ammonium compounds by liquid chromatography with mass spectrometry. Part I. Application to surface, waste and indirect discharge water samples in Austria  

Microsoft Academic Search

A method for simultaneous quantitative determination of alkyl benzyl, dialkyl and trialkyl quaternary ammonium compounds (QACs) has been developed, validated and subsequently applied to real water samples in Austria. The method employs liquid-liquid extraction (LLE) followed by liquid chromatography\\/tandem mass spectrometry (LC-MS\\/MS), using electrospray ionization (ESI) in positive mode. The overall method quantification limits range from 4 to 19ng\\/L for

Elena Martínez-Carballo; Andrea Sitka; Carmen González-Barreiro; Norbert Kreuzinger; Maria Fürhacker; Sigrid Scharf; Oliver Gans

2007-01-01

198

Time-of-flight high resolution versus triple quadrupole tandem mass spectrometry for the analysis of quaternary ammonium herbicides in drinking water  

Microsoft Academic Search

Conditions for the simultaneous determination of quaternary ammonium herbicides by liquid chromatography–electrospray–mass spectrometry were established. Two electrospray sources with different configurations and two mass analyzers were used: a Turbo Ionspray™ source with a triple quadrupole instrument and a Z-spray source with a time-of-flight (TOF) analyzer. The separation was performed using ion pair reversed phase chromatography. An on-line solid-phase extraction procedure

Oscar Núñez; Encarnación Moyano; Maria Teresa Galceran

2004-01-01

199

Investigation of double bond conversion, mechanical properties, and antibacterial activity of dental resins with different alkyl chain length quaternary ammonium methacrylate monomers (QAM)  

Microsoft Academic Search

In order to endow dental resin with antibacterial activity, a series of antibacterial quaternary ammonium methacrylate monomers (QAM) with different substituted alkyl chain length (from 10 to 18) were incorporated into commonly used 2,2-bis[4-(2?-hydroxy-3?-methacryloyloxy-propoxy)-phenyl]propane (Bis-GMA)\\/triethyleneglycol dimethacrylate (TEGDMA) (50?wt\\/50?wt) dental resin as immobilized antibacterial agents. Double bond conversion (DC), flexural strength (FS) and modulus (FM), and young and mature biofilms inhibition

Jingwei He; Eva Söderling; Pekka K. Vallittu; Lippo V. J. Lassila

2012-01-01

200

Quaternary ammonium analogs of ether lipids inhibit the activation of protein kinase C and the growth of human leukemia cell lines  

Microsoft Academic Search

Purpose: ET-18-OCH3 (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) is a representative of the first generation of antitumor ether lipids and is a model in the development\\u000a of new compounds including a series of quaternary ammonium analogs (QAA). In the present study, we evaluated the QAA as inhibitors\\u000a of cell growth and studied their mechanism of action. Methods: We compared the effects of the QAA on

Francesca Civoli; Larry W. Daniel

1998-01-01

201

Effects of freezing, drying, ultraviolet irradiation, chlorine, and quaternary ammonium treatments on the infectivity of myxospores of Myxobolus cerebralis for Tubifex tubifex.  

PubMed

The effects of freezing, drying, ultraviolet irradiation (UV), chlorine, and a quaternary ammonium compound on the infectivity of the myxospore stage of Myxobolus cerebralis (the causative agent of whirling disease) for Tubifex tubifex were examined in a series of laboratory trials. Freezing at either -20 degrees C or -80 degrees C for a period of 7 d or 2 months eliminated infectivity as assessed by the absence of production of the actinospore stage (triactinomyxons [TAMs]) from T. tubifex cultures inoculated with treated myxospores over a 4-5-month period. Myxospores retained infectivity when held in well water at 5 degrees C or 22 degrees C for 7 d and when held at 4 degrees C or 10 degrees C d for 2 months. In contrast, no TAMs were produced from T. tubifex cultures inoculated with myxospores held at 20 degrees C for 2 months. Drying of myxospores eliminated any evidence of infectivity for T. tubifex. Doses of UV from 40 to 480 mJ/cm2 were all effective for inactivating myxospores of M. cerebralis, although a few TAMs were detected in one replicate T. tubifex culture at 240 mJ/cm2 and in one replicate culture at 480 mJ/cm2. Treatments of myxospores with chlorine bleach at active concentrations of at least 500 mg/L for 15 min largely inactivated myxospore infectivity for T. tubifex. Likewise, there was no evidence of TAMs produced by T. tubifex inoculated with myxospores treated with alkyl dimethyl benzyl ammonium chloride (ADBAC) at 1,500 mg/L for 10 min. Treatments of myxospores with 1,000-mg/L ADBAC for 10 min reduced TAM production in T. tubifex cultures sevenfold relative to that in cultures inoculated with an equal number of untreated myxospores. These results indicate that myxospores of M. cerebralis demonstrate a selective rather than broad resistance to selected physical and chemical treatments, and this selective resistance is consistent with conditions that myxospores are likely to experience in nature. PMID:18783133

Hedrick, Ronald P; McDowell, Terry S; Mukkatira, Kaveramma; MacConnell, Elizabeth; Petri, Brian

2008-06-01

202

Disproportionation of dihydroarenes by Sol-Gel entrapped RhCl{sub 3}-quaternary ammonium ion pair catalysts  

SciTech Connect

The ion pairs generated from RhCl{sub 3}{center_dot}3H{sub 2}O and the quaternary ammonium salts [(C{sub 8}H{sub 17}){sub 3}NMe]Cl (Aliquat 336) and [Me{sub 3}N(CH{sub 2}){sub 3}Si(OMe){sub 3}]Cl were physically and chemically entrapped, respectively, in SiO{sub 2} sol-gel matrices under mild conditions. The resulting immobilized ion pairs proved to be stable, leach-proof, and recyclable catalysts for disproportionation of 1,3,-cyclohexadiene and several other vic-dihydroarenes. In these reactions, equimolar quantities of the respective tetrahydro- and fully aromatic compounds were obtained. The entrapped catalysts, in most cases, proved to be more efficient and more selective than their homogeneous analogues. The reaction rates and conversions were shown to depend strongly on steric effects of substituents and on the bulkiness of the substrate skeleton. The recorded first order kinetics in the substrates (organic reactants) suggests that the mechanism involves stepwise addition of two molecules of the dihydroarenes to the rhodium nucleus, and that the addition of the first substrate molecule is rate limiting. 28 refs., 5 figs., 2 tabs.

Rosenfeld, A.; Blum, J.; Avnir, D. [Hebrew Univ., Jerusalem (Israel)

1996-12-01

203

Synthesis, characterization and thermal properties of small R2R?2N+X--type quaternary ammonium halides  

NASA Astrophysics Data System (ADS)

Twenty-one R2R?2N+X- -type (R=methyl or ethyl, R?=alkyl, X=Br or I) quaternary ammonium (QA) halides have been prepared by using a novel one-pot synthetic route in which a formamide (dimethyl-, diethylformamide, etc.) is treated with alkyl halide in the presence of sodium or potassium carbonate. The formation of QA halides was verified with 1H-NMR, 13C-NMR, MS and elemental analysis. The crystal structures of four QA halides (two bromide and two iodide) were determined using X-ray single crystal diffraction, and the powder diffraction method was used to study the structural similarities between the single crystal and microcrystalline bulk material. The thermal properties of all compounds were studied using TG/DTA and DSC methods. The smallest compounds decomposed during or before melting. The decreasing trend of melting points was observed when the alkyl chain length was increased. The liquid ranges of 120 180 °C were observed for compounds with 5 6 carbon atoms in the alkyl chain. The low melting points and wide liquid ranges suggest potential applicability of these compounds for example as ionic liquids precursors.

Busi, Sara; Lahtinen, Manu; Mansikkamäki, Heidi; Valkonen, Jussi; Rissanen, Kari

2005-06-01

204

In situ x-ray diffraction studies of alkyl quaternary ammonium montmorillonite in a CO2 environment  

NASA Astrophysics Data System (ADS)

An in situ study was conducted using an x-ray diffractometer and a specially designed high pressure cell to examine the effects of carbon dioxide at different pressures and temperatures on three different modified montmorillonite species. These organoclays possessed organic pillars of quaternary ammonium surfactant with either one, two, or three long (C16-C18) alkyl chains attached to expand the galleries of the clay mineral. The three clay species were tested between 50 °C and 200 °C with carbon dioxide pressures between 0.1 and 8.4 MPa. Under these conditions, the three organoclays exhibited marked differences in their basal spacing depending on the surfactant used. The physical state of the intercalated surfactant was found to be of critical importance, with no changes in basal spacing noted until the organic component began to melt, in spite of CO2 being present. A pressure effect was also noted which delayed melting of the surfactants as the pressure of the system increased. In all cases, further cation exchange with residual sodium cation present in the galleries was observed in the presence of CO2 and above the melting state of the surfactant. The study included examination of the effect of rapid depressurization on the clay structure, which produced only a small change in basal spacing.

Thompson, M. R.; Balogh, M. P.; Speer, R. L.; Fasulo, P. D.; Rodgers, W. R.

2009-01-01

205

Extraction of benzene and naphthalene carboxylic acids using quaternary ammonium salts as a model study for the separation of coal oxidation products  

SciTech Connect

The ion-pair solvent extraction of benzene- and naphthalene-carboxylic acids has been investigated as a model study for the separation of coal oxidation products, which are formed by treatment with alkaline solutions at high temperatures. It was possible that benzene- and naphthalene-dicarboxylic acids are extracted into several types of organic solvents with quaternary ammonium ions. The extraction equilibrium constants (K{sub ex}) for benzoic acid, 1,2-benzenedicarboxylic acid, 1,3-benzenedicarboxylic acid, 1-naphthoic acid, 2-naphthoic acid, 2,3-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid into chloroform were determined at 20{sup o}C. The difference of K{sub ex} among the aromatic acids was sufficiently large for designing a separation method for these aromatic acids. It was unexpected that the extraction of dicarboxylic acids was slower than that of monocarboxylic acids, although the ion-pair formation of aromatic carboxylate ion with quaternary ammonium ion is normally considered as a diffusion control reaction in aqueous phase. Thus, this fact suggests that the phase transfer of the ion-pair from aqueous to organic phase is the rate-determining step. Liner-free-energy relationship was observed for the monocarboxylic acids using different quaternary ammonium salts while that was ambiguous for the dicarboxylic acids. This is due to the steric influence of the counter ions for the magnitude of K{sub ex}.

Kawamura, K.; Nagano, H.; Okuwaki, A. [Tohoku University, Miyagi (Japan). Graduate School of Environmental Studies

2005-07-01

206

Interactive effect of monocrotophos and ammonium chloride on the freshwater fish Oreochromis mossambicus with reference to lactate\\/pyruvate ratio  

Microsoft Academic Search

Sublethal effect of monocrotophos (pesticide) and ammonium chloride (fertilizer) was studied in the freshwater fish Oreochromis mossambicus, with reference to carbohydrate metabolism for a period of 96h. The glycogen content was analysed in liver and muscle, while the lactate and pyruvate were assessed in blood along with liver and muscle. The results revealed that the glycogen content was found to

K. Vijayavel; E. F. Rani; C. Anbuselvam; M. P. Balasubramanian

2006-01-01

207

Induction of ureogenesis in perfused liver of a freshwater teleost, Heteropneustes fossilis, infused with different concentrations of ammonium chloride  

Microsoft Academic Search

The induction pattern of urea cycle enzymes and the rate of urea-N excretion were studied with relation to ammonia load in the perfused liver of a freshwater ammoniotelic teleost, Heteropneustes fossilis, when infused with different concentrations of ammonium chloride for 60 min. Both urea-N excretion and uptake of ammonia by the perfused liver were found to be a saturable process.

N. Saha; J. Dkhar; B. K. Ratha

1995-01-01

208

A novel group of quaternary ammonium salts as ionic liquids and deep eutectic solvents  

NASA Astrophysics Data System (ADS)

A growing number of non-toxic and biodegradable deep eutectic solvents (DES) have been discovered in recent years. This group encompasses the solidified crystalline material 3-(2-aminopyrimidin-1-yl)propanoate (3-2AP), a primary ammonium cation that is a construct of a typical DES. Synthesis of 3-(2-aminopyrimidin-1-yl)propanoate by quarternerization of the amine in the aromatic ring creates a novel deep eutectic solvent. An additional alteration to the DES construct is observed with the formation of a zwitterion between the positively charged quartenary amine group and the negatively charged carboxylate counter ion. The molecular arrangement, or construct, of a deep eutectic solvent will determine both its structure and application in industry. This report describes the synthesis and characterization of an 80:20 urea/3-2AP eutectic mixture with a melting point of 50°C, nearly 120°C lower than the melting temperature of 3-2AP (172.5°C). A cytotoxicity profile for 3-2AP exposed to A549 bronchoaveolar carcinoma cells revealed an LD50 of 337.65 mug/ml.

Sparrow, Christopher R.

209

Direct comparison of the hygroscopic properties of ammonium sulfate and sodium chloride aerosol at relative humidities approaching saturation.  

PubMed

Holographic optical tweezers are used to make comparative measurements of the hygroscopic properties of single component aqueous aerosol containing sodium chloride and ammonium sulfate over a range of relative humidity from 84% to 96%. The change in RH over the course of the experiment is monitored precisely using a sodium chloride probe droplet with accuracy better than ±0.09%. The measurements are used to assess the accuracy of thermodynamic treatments of the relationship between water activity and solute mass fraction with particular attention focused on the dilute solute limit approaching saturation vapor pressure. The consistency of the frequently used Clegg-Brimblecombe-Wexler (CBW) treatment for predicting the hygroscopic properties of sodium chloride and ammonium sulfate aerosol is confirmed. Measurements of the equilibrium size of ammonium sulfate aerosol are found to agree with predictions to within an uncertainty of ±0.2%. Given the accuracy of treating equilibrium composition, the inconsistencies highlighted in recent calibration measurements of critical supersaturations of sodium chloride and ammonium sulfate aerosol cannot be attributed to uncertainties associated with the thermodynamic predictions and must have an alternative origin. It is concluded that the CBW treatment can allow the critical supersaturation to be estimated for sodium chloride and ammonium sulfate aerosol with an accuracy of better than ±0.002% in RH. This corresponds to an uncertainty of ?1% in the critical supersaturation for typical supersaturations of 0.2% and above. This supports the view that these systems can be used to accurately calibrate instruments that measure cloud condensation nuclei concentrations at selected supersaturations. These measurements represent the first study in which the equilibrium properties of two particles of chemically distinct composition have been compared simultaneously and directly alongside each other in the same environment. PMID:21067131

Walker, Jim S; Wills, Jon B; Reid, Jonathan P; Wang, Liangyu; Topping, David O; Butler, Jason R; Zhang, Yun-Hong

2010-11-10

210

Retention behavior of long chain quaternary ammonium homologues and related nitroso-alkymethylamines  

USGS Publications Warehouse

Several chromatographic methods have been utilized to study the retentionbehavior of a homologous series of n-alkylbenzyldimethylammonium chlorides (ABDAC) and the corresponding nitroso-n-alkylmethylamines (NAMA). Linear correlation of the logarithmic capacity factor (k') with the number of carbons in the alkyl chain provides useful information on both gas chromatographic (GC) and high-performance liquid chromatographich (HPLC) retention parameters of unknown components. Under all conditions empolyed, GC methodology has proved effective in achieving complete resolution of the homologous mixture of NMA despite its obvious inadequacy in the separation of E-Z configurational isomers. Conversely, normal-phase HPLC on silica demonstrates that the selectivity (a) value for an E-Z pair is much higher than that for an adjacent homologous pair. In the reversed-phase HPLC study, three different silica-based column systems were examined under various mobile phase conditions. The extent of variation in k' was found to be a function of the organic modifier, counter-ion concentration, eluent pH, nature of counter-ion, and the polarity and type of stationary phase. The k'—[NaClO4] profiles showed similar trends between the ABDAC and the NAMA series, supporting the dipolar electronic structures of the latter compounds. Mobile phase and stationary phase effects on component separation are described. The methodology presented establishes the utility of HPLC separation techniques as versatile analytical tools for practical application.

Abidi, S. L.

1985-01-01

211

The solubility of sulfur dioxide in aqueous solutions of sodium chloride and ammonium chloride in the temperature range from 313 K to 393 K at pressures up to 3.7 MPa: experimental results and comparison with correlations  

Microsoft Academic Search

The solubility of sulfur dioxide in aqueous solutions of single solutes sodium chloride and ammonium chloride was measured using a static method at temperatures from 313 K to 393 K and total pressures up to 3.7 MPa corresponding to gas molalities of up to 10 mol\\/kg. Similarily to the system sulfur dioxide–water, also in systems with sodium and ammonium chloride

Jianzhong Xia; Bernd Rumpf; Gerd Maurer

1999-01-01

212

Delivery of peptides to the blood and brain after oral uptake of quaternary ammonium palmitoyl glycol chitosan nanoparticles.  

PubMed

The clinical development of therapeutic peptides has been restricted to peptides for non-CNS diseases and parenteral dosage forms due to the poor permeation of peptides across the gastrointestinal mucosa and the blood-brain barrier. Quaternary ammonium palmitoyl glycol chitosan (GCPQ) nanoparticles facilitate the brain delivery of orally administered peptides such as leucine(5)-enkephalin, and here we examine the mechanism of GCPQ facilitated oral peptide absorption and brain delivery. By analyzing the oral biodistribution of radiolabeled GCPQ nanoparticles, the oral biodistribution of the model peptide leucine(5)-enkephalin and coherent anti-Stokes Raman scattering microscopy tissue images after an oral dose of deuterated GCPQ nanoparticles, we have established a number of facts. Although 85-90% of orally administered GCPQ nanoparticles are not absorbed from the gastrointestinal tract, a peak level of 2-3% of the oral GCPQ dose is detected in the blood 30 min after dosing, and these GCPQ particles appear to transport the peptides to the blood. Additionally, although peptide loaded nanoparticles from low (6 kDa) and high (50 kDa) molecular weight GCPQ are taken up by enterocytes, polymer particles with a polymer molecular weight greater than 6 kDa are required to facilitate peptide delivery to the brain after oral administration. By examining our current and previous data, we conclude that GCPQ particles facilitate oral peptide absorption by protecting the peptide from gastrointestinal degradation, adhering to the mucus to increase the drug gut residence time and transporting GCPQ associated peptide across the enterocytes and to the systemic circulation, enabling the GCPQ stabilized peptide to be transported to the brain. Orally administered GCPQ particles are also circulated from the gastrointestinal tract to the liver and onward to the gall bladder, presumably for final transport back to the gastrointestinal tract. PMID:22571402

Lalatsa, A; Garrett, N L; Ferrarelli, T; Moger, J; Schätzlein, A G; Uchegbu, I F

2012-05-21

213

Haemodynamic effects of the antiarrhythmic quaternary ammonium compound QX-572 in man.  

PubMed

The haemodynamic effects of N, N-bis(phenyl-carbamoylmethyl) dimethylammonium chloride (QX-572) in man were studied. A controlled study was performed to rule out a possible influence of the catheterization procedure as such on the results. Ten patients with mild to moderate aortic regurgitation were studied: based on clinical data the patients were divided into 2 groups of 5. Randomly it was decided that one group should constitute a control group receiving saline while the second group received QX-572 , MG/KG BODY WEIGHT. In both groups the administration was performed as a slow intravenous infusion during 30 minutes. Heart rate, pressures in brachial artery and right atrium, cardiac output, stroke volume, and systemic vascular resistance were determined before, during, and up to 30 minutes after completion of placebo or QX-572. These variable remained stable in the control group while QX-572 produced an increase in heart rate most pronounced at the end of the infusion period. A transient decrease in systolic and mean brachial artery pressure during the infusion, and during the same period a decrease in right atrial pressure. Cardiac output and systemic vascular resistance were unchanged by QX-572 but they were not measured during the infusion when the changes in pressures were most pronounced. QX-572 was thought to act as a peripheral vasodilator during the infusion. Left ventricular contractility was studied by means of pressure curves obtained from a catheter tip manometer placed in the left ventricle. The first derivative of the isovolumic left ventricular pressure at the highest level (45mmHg) common to all patients was used (dp/dt-45). No significant difference could be observed when comparing mean changes of dp/dt-45 for the two groups. In the control group there was a slight but significant increase in dp/dt-45 during the time of observation. In the QX-572 group the results varied between individuals. Two of the patients differed from all other patients in the control and QX-572 groups showing a decrease in dp/dt-45 which, when most pronounced at the end of the infusion period, was -31 and -28 per cent of the preinfusion levels, respectively. This decrease probably reflects reduction of contractility. It was concluded that QX-572 in a dose of 8 mg/kg body weight did not have any major haemodynamic drawbacks. PMID:1089426

Rydén, L; Hjalmarson A; Kvasnicka, J; Liander, B

1975-01-01

214

Haemodynamic effects of the antiarrhythmic quaternary ammonium compound QX-572 in man.  

PubMed Central

The haemodynamic effects of N, N-bis(phenyl-carbamoylmethyl) dimethylammonium chloride (QX-572) in man were studied. A controlled study was performed to rule out a possible influence of the catheterization procedure as such on the results. Ten patients with mild to moderate aortic regurgitation were studied: based on clinical data the patients were divided into 2 groups of 5. Randomly it was decided that one group should constitute a control group receiving saline while the second group received QX-572 , MG/KG BODY WEIGHT. In both groups the administration was performed as a slow intravenous infusion during 30 minutes. Heart rate, pressures in brachial artery and right atrium, cardiac output, stroke volume, and systemic vascular resistance were determined before, during, and up to 30 minutes after completion of placebo or QX-572. These variable remained stable in the control group while QX-572 produced an increase in heart rate most pronounced at the end of the infusion period. A transient decrease in systolic and mean brachial artery pressure during the infusion, and during the same period a decrease in right atrial pressure. Cardiac output and systemic vascular resistance were unchanged by QX-572 but they were not measured during the infusion when the changes in pressures were most pronounced. QX-572 was thought to act as a peripheral vasodilator during the infusion. Left ventricular contractility was studied by means of pressure curves obtained from a catheter tip manometer placed in the left ventricle. The first derivative of the isovolumic left ventricular pressure at the highest level (45mmHg) common to all patients was used (dp/dt-45). No significant difference could be observed when comparing mean changes of dp/dt-45 for the two groups. In the control group there was a slight but significant increase in dp/dt-45 during the time of observation. In the QX-572 group the results varied between individuals. Two of the patients differed from all other patients in the control and QX-572 groups showing a decrease in dp/dt-45 which, when most pronounced at the end of the infusion period, was -31 and -28 per cent of the preinfusion levels, respectively. This decrease probably reflects reduction of contractility. It was concluded that QX-572 in a dose of 8 mg/kg body weight did not have any major haemodynamic drawbacks.

Ryden, L; Hjalmarson A; Kvasnicka, J; Liander, B

1975-01-01

215

[Growth inhibition and mechanism of cetyltrimethyl ammonium chloride on Chlorella vulgaris].  

PubMed

Growth inhibition of cetyltrimethyl ammonium chloride (CTAC), a cationic surfactants, on Chlorella vulgaris was investigated at batch culture in laboratory. Furthermore, the corresponding mechanisms were studied by the determination of absorption capacity, Zeta potential, activity of acid phosphatase and ultrastructure of algae. Results show that the growth inhibition by CATC is enhanced with its concentration increasing from 0.1 mg/L to 1 mg/L, and 96 h-EC50 of CTAC is 0.18 mg/L. In the presence of 0.3 mg/L CTAC in 8 d, the inhibition efficiency of biomass reaches 70.7%. Meanwhile, the absorption of nitrogen and iron is inhibited 83.9% and 86.2% respectively with Zeta potential of algae cell increasing from -12.5 mV to -6.7 mV. Furthermore, the relative activity of acid phosphatase declines to 23.1% at the same time. Plasmolysis, distortion of pyrenoid and swelling of lysosome is observed in the cell. Above phenomena indicates that CTAC increases the Zeta potential of algae cell and thus inhibites the absorption of nitrogen and iron. In addition, CTAC may affect the metabolism of phosphorus and change the ultrastructure of algae cell. PMID:19662866

Xu, Yin; Ge, Fei; Tao, Neng-Guo; Zhu, Run-Liang; Wang, Na

2009-06-15

216

Determination of benzyltriethyl ammonium chloride from polymeric media by capillary electrophoresis with ultraviolet absorbance detection.  

PubMed

The importance of benzyltriethyl ammonium chloride (BTEAC) in industrial applications has stimulated the development of a number of methods for its determination. In this paper, a high performance capillary electrophoresis (CE) method, coupled with an extraction technique for determining BTEAC in organic matrices, was developed. BTEAC was extracted from organic samples with a 20 mM sodium phosphate solution. Sonication was used to improve extraction efficiency. The repeatability and recovery of the technique have been studied and it was proven that the technique is satisfactory for quantitative determination of BTEAC in organic matrices. Separation was achieved within 6 min in 20 mM sodium phosphate buffer at pH 5.0. The recovery was above 92%. The detection limit for BTEAC is 5 mg L(-1) with a signal-to-noise ratio of 3. The linear range of the technique is 5-100 mg L(-1). This method is simple, fast, low-cost, and can be easily used for product quality control in industrial laboratories. PMID:17386532

Lin, Weisheng; Shi, Haiying; May, Trisha; Shi, Honglan; Ma, Yinfa

2006-10-05

217

Surface chemical study on the covalent attachment of hydroxypropyltrimethyl ammonium chloride chitosan to titanium surfaces  

NASA Astrophysics Data System (ADS)

An anti-microbial and bioactive coating could not only reduce the probability of infection related to titanium implants but also support the growth of surrounding osteogenic cells. Our previous study has showed that hydroxypropyltrimethyl ammonium chloride chitosan (HACC) with a DS (degrees of substitution) of 18% had improved solubility and significantly higher antibacterial activities against three bacteria which were usually associated with infections in orthopaedics. In the current study, HACC with a DS of 18% coating was bonded to titanium surface by a three-step process. The titanium surface after each individual reaction step was analyzed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection (ATR) of Fourier-transformed infrared (FT-IR) spectroscopy. The XPS results demonstrated that there were great changes in the atomic ratios of C/Ti, O/Ti, and N/Ti after each reaction step. The XPS high resolution and corresponding devolution spectra of carbon, oxygen, nitrogen, and titanium were also in good coordination with the anticipated reaction steps. Additionally, the absorption bands around 3365 cm -1 (-OH vibration), 1664 cm -1 (Amide I), 1165 cm -1 ( ?as, C-O-C bridge), and the broad absorption bands between 958 cm -1 and 1155 cm -1 (skeletal vibrations involving the C-O stretching of saccharide structure of HACC) verified that HACC was successfully attached to titanium surface.

Xu, Xiaofen; Wang, Ling; Guo, Shengrong; Lei, Lei; Tang, Tingting

2011-10-01

218

Ion pair recognition of quaternary ammonium and iminium salts by uranyl-salophen compounds in solution and in the solid state.  

PubMed

Efficient ditopic receptors for quaternary ammonium and iminium salts have been obtained upon functionalization of the uranyl-salophen unit with conformationally flexible side arms bearing phenyl or beta-naphthyl substituents. Binding affinities in chloroform solution have been measured for a large number of quaternary salts comprising tetramethylammonium (TMA), tetrabutylammonium (TBA), acetylcholine (ACh), N-methylpyridinium (NMP), and N-methylisoquinolinium (NmiQ) cations. Recognition of the anion partner is ensured by coordination to the hard Lewis acidic uranyl center, whereas cation-pi/CH-pi interactions of the quaternary ions are established with the aromatic pendants. The role of the cation-anion interactions on the dynamics of exchange between the free and complexed species is discussed. Solid-state structures have been obtained for a few salt-receptor combinations. In the solid state, side-armed receptor molecules form assemblies that enclose ion pair aggregates of varying composition and structure, including AChCl dimers, two different kinds of tetrameric (TMA)Cl clusters, and unidimentional salt strips of (NMP)Br. The lack of side arms as preferential binding sites for the polar quaternary cations prevents association patterns of the kinds formed with the side-armed receptors, as shown by the crystal structure of the complex of (TMA)Cl with the parent uranyl-salophen receptor. PMID:17338524

Cametti, Massimo; Nissinen, Maija; Cort, Antonella Dalla; Mandolini, Luigi; Rissanen, Kari

2007-03-06

219

Efficacy of dimethyl benzyl ammonium chloride and microbial contamination studies in a modern sugarcane milling unit in Thailand  

Microsoft Academic Search

The modern milling process at Mitr Phuveing Sugar factory takes less than 10 min from cane stalk to mixed juice stage before\\u000a the liming process. However, the microorganisms still affect sugar yield in the factory. The efficacy of dimethyl benzyl ammonium\\u000a chloride (DBAC) and microbial contamination in the sugar cane juice from milling process were studied. The inhibitory effect\\u000a of

N. Milintawisamai; C. Ngasan; R. Maungmontri; W. Buttapeng; R. Kotrsri; A. Pliansinchai; P. Weerathaworn

2009-01-01

220

Synthesis and structural studies of a new class of quaternary ammonium salts, which are derivatives of cage adamanzane type aminal 1, 3, 6, 8-tetraazatricyclo[4.3.1.13,8]undecane (TATU)  

PubMed Central

Background Novel mono N-alkyl quaternary ammonium salts (3a-f) were prepared using the Menschutkin reaction from the cage adamanzane type aminal 1,3,6,8-tetraazatricyclo[4.3.1.13,8]undecane (TATU) and alkyl iodides, such as methyl, ethyl, propyl, butyl, pentyl and hexyl iodide (2a-f), in dry acetonitrile at room temperature. Results The structures of these new quaternary ammonium salts were established using various spectral and electrospray ionization mass spectrometry (ESI-MS) analyses. Compound (3b) was also analyzed using X-ray crystallography. Conclusion It was noted that alkyl chain length did not significantly affect the reaction because all employed alkyl iodide electrophiles reacted in a similar fashion with the aminal 1 to produce the corresponding mono N-quaternary ammonium salts, which were characterized by spectroscopic and analytical techniques.

2011-01-01

221

Fire performance and decay resistance of solid wood and plywood treated with quaternary ammonia compounds and common fire retardants  

Microsoft Academic Search

In this study, the fire performance and decay resistance of solid wood and plywood treated with quaternary ammonia compounds\\u000a (didecyl dimethyl ammonium chloride (DDAC) and didecyl dimethyl ammonium tetrafluoroborate (DBF)) were compared with the performance\\u000a of untreated control specimens and specimens treated with common fire retardants ((monoammonium phosphate (MAP), diammonium\\u000a phosphate (DAP) and ammonium sulphate (AS)). Test specimens were treated

Evren Terzi; S. Nami Kartal; Robert H. White; Katsumi Shinoda; Yuji Imamura

2011-01-01

222

Final Report on the Safety Assessment of PPG-9, -25, and -40 Diethylmonium Chloride  

Microsoft Academic Search

PPG-9, -25, and -40 Diethyhnonium Chloride are quaternary ammonium salts that function as antistatic agents in cosmetic formulations. Only PPG-9 and -25 Diethylmonium Chloride are reported to be used. Neither animal test data nor clinical test results were available. No data were provided in response to requests of interested parties to supply the needed data. Accordingly, the available data are

F. Alan Andersen

1999-01-01

223

Selectivity control in synergistic liquid-liquid anion exchange of univalent anions via structure-specific cooperativity between quaternary ammonium cations and anion receptors.  

PubMed

Two anion receptors enhance liquid-liquid anion exchange when added to quaternary alkylammonium chloride anion exchangers, but with a striking dependence on the structure of the alkylammonium cation that suggests a supramolecular cooperative effect. Two anion receptors were investigated, meso-octamethylcalix[4]pyrrole (C4P) and the bisthiourea tweezer 1,1'-(propane-1,3-diyl)bis(3-(4-sec-butylphenyl)thiourea (BTU). Whereas synergism is comparatively weak when either methyltri(C(8,10))alkylammonium chloride (Aliquat 336) or tetraheptylammonium chloride is used with the BTU receptor, synergism between C4P and Aliquat 336 is so pronounced that anion exchange prefers chloride over more extractable nitrate and trifluoroacetate, effectively overcoming the ubiquitous Hofmeister bias. A thermochemical analysis of synergistic anion exchange has been provided for the first time, resulting in the estimation of binding constants for C4P with the ion pairs of A336(+) with Cl(-), Br(-), OAc(F3)(-), NO(3)(-), and I(-). PMID:22931168

Borman, Christopher J; Bonnesen, Peter V; Moyer, Bruce A

2012-09-14

224

Qualitative and quantitative analysis of quaternary ammonium alkaloids from Rhizoma Corydalis by matrix-assisted laser desorption\\/ionization Fourier transform mass spectrometry coupled with a selective precipitation reaction using Reinecke salt  

Microsoft Academic Search

A major problem hampering the use of MALDI-MS for quantitative measurements is the inhomogeneous distribution of analytes and matrices in sample preparations. In this study, an aerospray method was utilized for sample preparation method to improve sample homogeneity across stainless steel targets for quantitative analysis of quaternary ammonium alkaloids (QAAs). A selective precipitation reaction with Reinecke salt known to selectively

Zhi-hong Cheng; Yin-long Guo; Hao-yang Wang; Guo-qiang Chen

2006-01-01

225

Theoretical problems associated with the use of acetic anhydride as a co-solvent for the non-aqueous titration of hydrohalides of organic bases and quaternary ammonium salts  

Microsoft Academic Search

A potentiometric titration study of organic base hydrohalides and quaternary ammonium salts using perchloric acid as the titrant and a mixture of acetic anhydride and acetic acid as the solvent was carried out and the titration mixture was analysed by NMR in order to clarify the chemistry of the reactions involved. It was found that in contrast to the general

Gergely Völgyi; Szabolcs Béni; Krisztina Takács-Novák; Sándor Görög

2010-01-01

226

Synthesis and structure of selected quaternary N-(1,4-anhydro-5-deoxy-2,3-O-isopropylidene-D,L-ribitol-5-yl)ammonium salts.  

PubMed

The syntheses have been developed for quaternary N-(1,4-anhydro-5-deoxy-2,3-O-isopropylidene-D,L-ribitol-5-yl)ammonium salts derived from five aromatic amines, pyridine, 2-methylpyridine, 3-carbamoylpyridine, 4-(N,N-dimethylamino)pyridine, and quinoline, as well as two tertiary aliphatic amines, trimethylamine and triethylamine. Reactions of 1,4-anhydro-2,3-O-isopropylidene-5-O-tosyl-D,L-ribitol with tri-n-propylamine and tri-n-butylamine were unsuccessful. The products were identified on the basis of their 1H and 13C NMR spectra. The structure of N-(1,4-anhydro-5-deoxy-2,3-O-isopropylidene-D,L-ribitol-5-yl)trimethylammonium tosylate was additionally elucidated by X-ray diffractometry. PMID:15388350

Skorupa, Eugenia; Dmochowska, Barbara; Pellowska-Januszek, Lucyna; Wojnowski, Wies?aw; Chojnacki, Jaros?aw; Wi?niewski, Andrzej

2004-10-01

227

Highly sensitive, colorimetric detection of mercury(II) in aqueous media by quaternary ammonium group-capped gold nanoparticles at room temperature.  

PubMed

We provide a highly sensitive and selective assay to detect Hg(2+) in aqueous solutions using gold nanoparticles modified with quaternary ammonium group-terminated thiols at room temperature. The mechanism is the abstraction of thiols by Hg(2+) that led to the aggregation of nanoparticles. With the assistance of solar light irradiation, the detection limit can be as low as 30 nM, which satisfies the guideline concentration of Hg(2+) in drinking water set by the WHO. In addition, the dynamic range of detection is wide (3 × 10(-8)-1 × 10(-2) M). This range, to our best knowledge, is the widest one that has been reported so far in gold nanoparticle (AuNP)-based assays for Hg(2+). PMID:21069969

Liu, Dingbin; Qu, Weisi; Chen, Wenwen; Zhang, Wei; Wang, Zhuo; Jiang, Xingyu

2010-11-11

228

Determination of selected quaternary ammonium compounds by liquid chromatography with mass spectrometry. Part I. Application to surface, waste and indirect discharge water samples in Austria.  

PubMed

A method for simultaneous quantitative determination of alkyl benzyl, dialkyl and trialkyl quaternary ammonium compounds (QACs) has been developed, validated and subsequently applied to real water samples in Austria. The method employs liquid-liquid extraction (LLE) followed by liquid chromatography/tandem mass spectrometry (LC-MS/MS), using electrospray ionization (ESI) in positive mode. The overall method quantification limits range from 4 to 19ng/L for the enrichment of 500mL water samples and analyte recoveries are between 80 and 99%. The method was applied to 62 of the respective water samples without filtration to avoid the loss of the analytes due to the high adsorption capacity of these compounds. Maxima in the mg/L range, especially in the wastewater of hospitals and laundries, could be detected for the selected target compounds. PMID:16835005

Martínez-Carballo, Elena; Sitka, Andrea; González-Barreiro, Carmen; Kreuzinger, Norbert; Fürhacker, Maria; Scharf, Sigrid; Gans, Oliver

2006-07-10

229

Isothermal vapour-liquid equilibria for ternary and quaternary systems of butyl chlorides with nheptane, toluene and methylcyclohexane at 323.15 K  

Microsoft Academic Search

Isothermal P, x and y data were measured in ternary and quaternary systems containing one of butyl chlorides (1-chlorobutane, 2-chlorobutane, 2-chloro-2-methylpropane) with n-heptane, toluene and methylcyclohexane. The data were smoothed by means of the maximum likelihood method using 3-suffix Margules, Van Laar, Wilson, NRTL (? = 1) and UNIQUAC equations. The DISQUAC model was applied to the prediction of data

Omar Dahmani; Ivan Wichterle; Ahmed Ait-Kaci

1997-01-01

230

Adsorption of alkyl-dimethyl-benzyl-ammonium chloride on low-weight greige and bleached cotton nonwovens in different aqueous environments  

Technology Transfer Automated Retrieval System (TEKTRAN)

Previous research has shown the adsorption of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC) on cotton nonwovens is dependent on pretreatment of the substrate, more specifically whether it is greige or bleached fabric. In this work we examine the effect of varying the chemical and physical propert...

231

Effect of varying nonwoven cotton substrate and the properties of the surfactant solution upon the adsorption of aqueous solutions of alkyl-dimethyl-benzyl-ammonium chloride  

Technology Transfer Automated Retrieval System (TEKTRAN)

The adsorption of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant commonly employed as an antimicrobial agent, on greige, alkaline scoured, and bleached nonwoven cotton fabrics was investigated at varying surfactant concentrations using UV/vis spectroscopy. Results show greige...

232

EPR and optical absorption study of Cr 3+-doped tetramethyl ammonium cadmium chloride single crystals  

Microsoft Academic Search

EPR study of Cr3+-doped tetramethyl cadmium chloride (TMCC) single crystals is carried out at room temperature. The crystal field and spin-Hamiltonian parameters are evaluated from the resonance line positions of different lines observed in the EPR spectra. The g and D parameter values are found to be g=1.9741±0.0002 and D=553±2×10?4cm?1, respectively. EPR data indicate that the site symmetry of Cr3+

Ram Kripal; Har Govind; S. K. Gupta; Manju Arora

2006-01-01

233

Impact of Bicarbonate, Ammonium Chloride, and Acetazolamide on Hepatic and Renal SLC26A4 Expression  

Microsoft Academic Search

SLC26A4 encodes pendrin, a transporter exchanging anions such as chloride, bicarbonate, and iodide. Loss of function mutations of SLC26A4 cause Pendred syndrome characterized by hearing loss and enlarged vestibular aqueducts as well as variable hypothyroidism and goiter. In the kidney, pendrin is expressed in the distal nephron and accomplishes HCO3- secretion and Cl- reabsorption. Renal pendrin expression is regulated by

Ioana Alesutan; Arezoo Daryadel; Nilufar Mohebbi; Lisann Pelzl; Christina Leibrock; Jakob Voelkl; Soline Bourgeois; Silvia Dossena; Charity Nofziger; Markus Paulmichl; Carsten A. Wagner; Florian Lang

2011-01-01

234

N,N-Di-methyl-dehydro-abietyl-ammonium chloride ethanol monosolvate.  

PubMed

The title compound {systematic name: 1-[(1R,4aS,10aR)-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octa-hydro-phenan-thren-1-yl]-N,N-di-methyl-methanaminium chloride ethanol monosolvate}, C22H36N(+)·Cl(-)·C2H6O, was synthesized from dehydroabietylamine by N-methyl-ation with formaldehyde/formic acid and transformation into the hydro-chloride. The de-hydro-abietyl moiety exhibits the usual conformation with the two cyclo-hexane rings in chair and half-chair conformations and a trans-ring junction. The crystal structure is built up from columns of the de-hydro-abietyl moieties stacked along the a axis. These columns are held together by the chloride ions via N-H?Cl and C-H?Cl inter-actions, which establish a two-dimensional network parallel to (010). The ethanol solvent mol-ecules are located between the columns and anchored via O-H?Cl hydrogen bonds. PMID:23795117

Huang, Xiu-Zhi; Rao, Xiao-Ping; Cui, Yan-Jie

2013-05-25

235

Reactive extraction of d, l-?-phenylglycine with a quaternary ammonium salt: Effect of hydroxide anions and water coextraction  

Microsoft Academic Search

The extraction equilibria of ?-phenylglycine in alkaline solutions with tri-n-octylmethylammonium chloride (TOMAC) (10%, v\\/v) in 1-decanol as diluent have been studied. Hydroxide anion and water co-extraction were also investigated. Equilibrium constants for the extraction of phenylglycine and OH- ions have been determined experimentally at 20°C, being KePhg=1.09 and KeOH=0.30. A mathematical model has been developed to predict the equilibrium concentrations

María Jesús González-Muñoz; Susana Luque; José R. Álvarez; José Coca

2006-01-01

236

Catalytic dehydrochlorination of polyvinyl chloride in two-phase systems  

SciTech Connect

The catalytic activity of quaternary ammonium salts (QAS), whose cation and anion structures are different, and the mechanism of catalytic two-phase dehydrochlorination of polyvinyl chloride (PVC) are studied. Under phase-transfer conditions, dehydrochlorination of PVC is shown to proceed at the interface via an ionic mechanism in the presence of quaternary ammonium salts. The catalytic activity of QAS is governed by both the cation lipophilicity and the anion nature and increases as alcohols are introduced into the reaction mixture. The alcohol nature does not influence the extent of the reaction completion, but it does effect the supermolecular structure of the polyacetylene synthesized.

Leplyanin, G.V.; Salimgareeva, V.N.; Sannikova, N.S. [Institute of Organic Chemistry, Ufa (Russian Federation)

1994-11-01

237

Study of the activity of quaternary ammonium compounds in the mitigation of biofouling in heat exchangers-condensers cooled by seawater.  

PubMed

The effectiveness of two quaternary ammonium compounds (QACs) (non-oxidising biocides) to reduce the growth of biofilm adhering to the tubes of a heat exchanger-condenser cooled by seawater was evaluated. Their effectiveness was compared to that of a conventional oxidising biocide (sodium hypochlorite [NaOCl]) under the same testing conditions. Each biocide was applied intermittently (6?h on, 6?h off) in a first shock stage (1.5?ppm over 8?days) and a second stabilising stage (0.5?ppm over 20?days). The results showed that the antifouling effectiveness of the first of the QACs (fifth generation) was comparable to that shown by the oxidising power of NaOCl. Although the reaction time was longer than that of NaOCl, both the compounds removed the biofilm, and the tube was practically restored to its clean condition. Treatment with the second of the QACs (fourth generation) allowed for the stabilisation of biofilm growth, but not for its removal. Ecotoxicology studies classified the QACs as environmentally harmless under the testing conditions. PMID:24067104

Trueba, Alfredo; Otero, Félix M; González, José A; Vega, Luis M; García, Sergio

2013-10-01

238

Investigation of double bond conversion, mechanical properties, and antibacterial activity of dental resins with different alkyl chain length quaternary ammonium methacrylate monomers (QAM).  

PubMed

In order to endow dental resin with antibacterial activity, a series of antibacterial quaternary ammonium methacrylate monomers (QAM) with different substituted alkyl chain length (from 10 to 18) were incorporated into commonly used 2,2-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)-phenyl]propane (Bis-GMA)/triethyleneglycol dimethacrylate (TEGDMA) (50 wt/50 wt) dental resin as immobilized antibacterial agents. Double bond conversion (DC), flexural strength (FS) and modulus (FM), and young and mature biofilms inhibition effectiveness of prepared dental resins were studied and Bis-GMA/TEGDMA without QAM was used as reference. Results showed that there was no significant difference on DC, FS, and FM between copolymer with and without 5 wt% QAM. Substituted alkyl chain length of QAM had no influence on DC, FS, and FM of copolymer, but had influence on antibacterial activity of copolymer. Antibacterial activity of copolymer increased with increasing of substituted alkyl chain length of QAM, and the sequence followed as 5%C10 < 5%C11 ? 5%C12 < 5%C16 ? 5%C18. Copolymers containing C18 and C16 had the best inhibition effectiveness on both young biofilm and mature biofilm, copolymers containing C12 and C11 only had inhibition effectiveness on young biofilm and copolymer containing C10 had none inhibition effectiveness on neither young biofilm nor mature biofilm. PMID:23565868

He, Jingwei; Söderling, Eva; Vallittu, Pekka K; Lassila, Lippo V J

2012-08-13

239

Cr(VI) sorption behavior from aqueous solutions onto polymeric microcapsules containing a long-chain quaternary ammonium salt: kinetics and thermodynamics analysis.  

PubMed

This work studies the adsorption of Cr(VI) ions from an aqueous acid solution on hydrophobic polymeric microcapsules containing a long-chain quaternary ammonium salt-type extractant immobilized in their pore structure. The microcapsules were synthesized by adding the extractant Aliquat 336 during the in situ radical copolymerization of the monomers styrene (ST) and ethylene glycol dimethacrylate (EGDMA). The microcapsules, which had a spherical shape with a rough surface, behaved as efficient adsorbents for Cr(VI) at the tested temperatures. The results of kinetics experiments carried out at different temperatures showed that the adsorption process fits well to a pseudo-second-order with an activation energy of 82.7 kJ mol(-1), confirming that the sorption process is controlled by a chemisorption mechanism. Langmuir's isotherms were found to represent well the experimentally observed sorption data. Thermodynamics parameters, namely, changes in standard free energy (DeltaG(0)), enthalpy (DeltaH(0)), and entropy (DeltaS(0)), are also calculated. The results indicate that the chemisorption process is spontaneous and exothermic. The entropy change value measured in this study shows that metal adsorbed on microcapsules leads to a less chaotic system than a liquid-liquid extraction system. PMID:19640641

Barassi, Giancarlo; Valdés, Andrea; Araneda, Claudio; Basualto, Carlos; Sapag, Jaime; Tapia, Cristián; Valenzuela, Fernando

2009-07-08

240

Synthesis, characterization and thermal properties of small R {sub 2} R {sup '} {sub 2}N{sup +} X {sup -}-type quaternary ammonium halides  

SciTech Connect

Twenty-one R {sub 2} R {sup '} {sub 2}N{sup +} X {sup -} -type (R=methyl or ethyl, R {sup '}=alkyl, X=Br or I) quaternary ammonium (QA) halides have been prepared by using a novel one-pot synthetic route in which a formamide (dimethyl-, diethylformamide, etc.) is treated with alkyl halide in the presence of sodium or potassium carbonate. The formation of QA halides was verified with {sup 1}H-NMR, {sup 13}C-NMR, MS and elemental analysis. The crystal structures of four QA halides (two bromide and two iodide) were determined using X-ray single crystal diffraction, and the powder diffraction method was used to study the structural similarities between the single crystal and microcrystalline bulk material. The thermal properties of all compounds were studied using TG/DTA and DSC methods. The smallest compounds decomposed during or before melting. The decreasing trend of melting points was observed when the alkyl chain length was increased. The liquid ranges of 120-180 deg. C were observed for compounds with 5-6 carbon atoms in the alkyl chain. The low melting points and wide liquid ranges suggest potential applicability of these compounds for example as ionic liquids precursors.

Busi, Sara [Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, FIN-40014 Jyvaeskylaen yliopisto (Finland); Lahtinen, Manu [Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, FIN-40014 Jyvaeskylaen yliopisto (Finland)]. E-mail: makrla@cc.jyu.fi; Mansikkamaeki, Heidi [NanoScience Center, Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, FIN-40014 Jyvaeskylaen yliopisto (Finland); Valkonen, Jussi [Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, FIN-40014 Jyvaeskylaen yliopisto (Finland); Rissanen, Kari [NanoScience Center, Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, FIN-40014 Jyvaeskylaen yliopisto (Finland)

2005-06-15

241

One-pot synthesis of dendritic gold nanostructures in aqueous solutions of quaternary ammonium cationic surfactants: effects of the head group and hydrocarbon chain length.  

PubMed

Hierarchical, three-fold symmetrical dendritic gold was prepared in an aqueous solution of the quaternary ammonium cationic surfactant dodecyltrimethylammonium bromide (DTAB). Similar surfactants with different head groups and hydrocarbon chain lengths were also used for comparison. Two-fold and one-fold symmetrical dendritic gold nanostructures were obtained in N-dodecyl-N-methylpyrrolidinium bromide (C(12)-MPB) and dodecyltriethylammonium bromide (DTEAB) aqueous solutions, respectively. Longer hydrocarbon chain lengths were unfavorable for the formation of dendritic nanostructures. The interaction energies between the individual surfactants and Au (111) plane were calculated using molecular dynamics simulations. Based on a series of contrast experiments and molecular dynamics simulations, the possible growth mechanism and fabrication process of the dendritic structures were proposed. The DTAB-capped, three-fold gold dendrites exhibited good surface-enhanced Raman scattering (SERS) sensitivity toward rhodamine 6G (R6G), indicating their potential for use in SERS-based detections and analysis. This work provides a simple and effective strategy for fabricating dendritic gold nanostructures in aqueous solutions. PMID:22877504

Huang, Deping; Qi, Yuanyuan; Bai, Xiangtao; Shi, Lijuan; Jia, Han; Zhang, Dongju; Zheng, Liqiang

2012-08-17

242

Sorption of uranium(VI) ions from hydrochloric acid and ammonium chloride solutions by anion exchangers  

SciTech Connect

The sorption of macroscopic quantities of uranium from solutions of UO/sub 2/Cl/sub 2/ containing HCl and NH/sub 4/Cl in concentrations from 0.0 to 6.0 M by the AV-17 x 8, AV-16G, EDE-10P, AN-31, AN-2F, AN22, and AN-251 anion exchangers has been investigated under static conditions. The sorption isotherms are described by an equation similar to Freundlich's equation: K/sub d/ = K tilde x C/sub eq/sup 1/z/ or log K/sub d/ = log K tilde + 1/z x log C/sub eq/. Equations describing the dependence of the sorbability (or K/sub d/) on the equilibrium concentration of uranium in the solution have been obtained with the aid of the least-squares method. Conclusions regarding the chemistry of the exchange of uranium ions on anion exchangers in chloride solutions have been drawn on the basis of the UV spectra of the original solutions and the IR spectra of the ion exchangers obtained in this work, as well as the established general laws governing sorption.

Pakholkov, V.S.; Denisova, L.A.; Rychkov, V.N.; Kurnosenko, N.A.

1988-01-01

243

Assessment of the toxicity of linear alkylbenzene sulfonate and quaternary alkylammonium chloride by measuring 13C-glycerol in Dunaliella sp  

Microsoft Academic Search

The toxic effects of linear alkylbenzenesulfonate (LAS) and quaternary alkylammonium chloride on Dunaliella sp. were studied by measuring 13C-glycerol. 13C-glycerol (five isomers of [1,2,1?-13C1,2,3]-glycerol) was produced in Dunaliella sp. from 13C-sodium bicarbonate added and the amounts of 13C-glycerol was lowered quantitatively with increased concentration of surfactants. The ratio of glycerol to 13C-glycerol was found to be about 45 : 55

Akiko Utsunomiya; Tomohiko Watanuki; Kazuhiro Matsushita; Masami Nishina; Isao Tomita

1997-01-01

244

Scanning force microscopy of circular and linear plasmid DNA spread on mica with a quaternary ammonium salt.  

PubMed Central

Scanning force microscopy (SFM) offers the potential for subnanometer resolution in the investigation of nucleic acids, proteins, and their complexes. SFM is not bound by the requirement of classical transmission electron microscopy (TEM) for contrast enhancement through shadow casting or negative staining. A primary challenge, however, has been the reproducible fixation of samples on an atomically flat surface such as mica. We have developed a method for the routine imaging by SFM of supercoiled, relaxed, and linearized plasmid DNA, immobilized on freshly cleaved mica through the spreading action of benzyldimethylalkylammonium chloride (BAC) at micromolar concentrations. A reproducibly high yield of well-spread, dispersed molecules is obtained and background contamination is minimal. The contour lengths of the relaxed and linearized molecules imaged in air agree well with the helical rise (3.4 A/bp) of B-DNA in solution. We have also introduced the use of quantitative image analysis of SFM images to determine apparent molecular width and height over the entire molecular path. Images

Schaper, A; Pietrasanta, L I; Jovin, T M

1993-01-01

245

Removal of ammonium chloride generated by ammonia slip from the SNCR process in municipal solid waste incinerators.  

PubMed

The selective non-catalytic reduction (SNCR) process is one of the methods used to reduce NO(x) to N(2) and H(2)O by injecting NH(3) or urea solution into a high-temperature furnace. Merits of this method include simple handling, low cost, and energy savings. However, a critical problem of the SNCR process is the generation of ammonia slip; in reactions with HCl in flue gas, ammonium chloride is generated and forms detached white plumes near the stack. Using a laboratory-scale experimental apparatus, we examined the possibility of NH(4)Cl collection and removal by a bag filter (BF). The molar NH(3)/HCl ratio of the compound collected at the filter was nearly one, regardless of gas temperature, retention time, and concentration, confirming the formation of NH(4)Cl. The NH(4)Cl generation ratio increased as reaction temperature decreased, indicating that the collection efficiency of NH(4)Cl should increase if the BF is operated at the lowest possible temperature while avoiding the critical point causing low-temperature corrosion (e.g., 150 degrees C). In addition, the use of activated carbon injection in the front of the BF and the dust layer on the BF are expected to capture slipped ammonia at the BF and reduce NH(4)Cl fume generation in the stack. PMID:19108871

Hwang, In-Hee; Minoya, Hiroshi; Matsuto, Toshihiko; Matsuo, Takayuki; Matsumoto, Akihiro; Sameshima, Ryoji

2008-12-23

246

The Variation of the Adiabatic and Isothermal Elastic Moduli and Coefficient of Thermal Expansion with Temperature through the lambda-Point Transition in Ammonium Chloride  

Microsoft Academic Search

Measurements of the temperature variation of the adiabatic and isothermal Young's and rigidity moduli and of the coefficient of thermal expansion of pressed specimens of ammonium chloride in the neighborhood of the lambda-point transition at 242.8°K are reported. It is found that a large difference exists between the adiabatic and isothermal compressibilities below the critical temperature, and hence a large

Andrew W. Lawson

1940-01-01

247

Combinatorial materials research applied to the development of new surface coatings IX: an investigation of novel antifouling/fouling-release coatings containing quaternary ammonium salt groups.  

PubMed

Polysiloxane coatings containing chemically-bound ("tethered") quaternary ammonium salt (QAS) moieties were investigated for potential application as environmental-friendly coatings to control marine biofouling. A combinatorial/high-throughput approach was applied to the investigation to enable multiple variables to be probed simultaneously and efficiently. The variables investigated for the moisture-curable coatings included QAS composition, ie alkyl chain length, and concentration as well as silanol-terminated polysiloxane molecular weight. A total of 75 compositionally unique coatings were prepared and characterized using surface characterization techniques and biological assays. Biological assays were based on two different marine microorganisms, a bacterium, Cellulophaga lytica and a diatom, Navicula incerta, as well as a macrofouling alga, Ulva. The results of the study showed that all three variables influenced coating surface properties as well as antifouling (AF) and fouling-release (FR) characteristics. The incorporation of QAS moieties into a polysiloxane matrix generally resulted in an increase in coating surface hydrophobicity. Characterization of coating surface morphology revealed a heterogeneous, two-phase morphology for many of the coatings investigated. A correlation was found between water contact angle and coating surface roughness, with the contact angle increasing with increasing surface roughness. Coatings based on the QAS moiety containing the longest alkyl chain (18 carbons) displayed the highest micro-roughness and, thus, the most hydrophobic surfaces. With regard to AF and FR properties, coatings based on the 18 carbon QAS moieties were very effective at inhibiting C. lytica biofilm formation and enabling easy removal of Ulva sporelings (young plants) while coatings based on the 14 carbon QAS moities were very effective at inhibiting biofilm growth of N. incerta. PMID:18368587

Majumdar, Partha; Lee, Elizabeth; Patel, Nehal; Ward, Kaley; Stafslien, Shane J; Daniels, Justin; Chisholm, Bret J; Boudjouk, Philip; Callow, Maureen E; Callow, James A; Thompson, Stephanie E M

2008-01-01

248

Combinatorial materials research applied to the development of new surface coatings XV: an investigation of polysiloxane anti-fouling/fouling-release coatings containing tethered quaternary ammonium salt groups.  

PubMed

As part of ongoing efforts aimed at the development of extensive structure?property relationships for moisture-curable polysiloxane coatings containing tethered quaternary ammonium salt (QAS) moieties for potential application as environmental friendly coatings to combat marine biofouling, a combinatorial/high-throughput (C/HT) study was conducted that was focused on four different compositional variables. The coatings that were investigated were derived from solution blends of a silanol-terminated polydimethylsiloxane (HO-PDMS-OH), QAS-functional alkoxysilane, and methyltriacetoxysilane. The compositional variables investigated were alkoxysilane functionality of the QAS-functional silane, chain length of the monovalent alkyl group attached to the QAS nitrogen atom, concentration of the QAS-functional alkoxysilane, and molecular weight of the HO-PDMS-OH. Of these variables, the composition of the alkoxysilane functionality of the QAS-functional silane was a unique variable that had not been previously investigated. The antifouling (AF) and fouling-release (FR) characteristics of the 24 unique coating compositions were characterized using HT assays based on three different marine microorganisms, namely, the two bacteria, Cellulophaga lytica and Halomonas pacifica, and the diatom, Navicula incerta. Coatings surfaces were characterized by surface energy, water contact angle hysteresis, and atomic force microscopy (AFM). A wide variety of responses were obtained over the compositional space investigated. ANOVA analysis showed that the compositional variables and their interactions significantly influenced AF/FR behaviors toward individual marine microorganisms. It was also found that utilization of the ethoxysilane-functional QASs provided enhanced AF character compared to coatings based on methoxysilane-functional analogues. This was attributed to enhanced surface segregation of QAS groups at the coating-air interface and confirmed by phase images using AFM. PMID:21480666

Majumdar, Partha; Crowley, Elizabeth; Htet, Maung; Stafslien, Shane J; Daniels, Justin; VanderWal, Lyndsi; Chisholm, Bret J

2011-04-15

249

Degradation of benzyldimethyl hexadecylammonium chloride by Bacillus niabensis and Thalassospira sp. isolated from marine sediments  

Microsoft Academic Search

Following enrichment in its presence, two strains of bacteria, isolated from marine sediments, were shown to degrade the quaternary ammonium surfactant benzyldimethyl hexadecylammonium chloride (BDHAC) in a minimal salts medium. The bacteria identified by 16S ribosomal deoxyribonucleic acid sequencing were shown to belong to several genera and determined to be Bacillus niabensis and Thalassospira sp. Initial investigations demonstrated that the

D. E. Bassey; S. J. W. Grigson

2011-01-01

250

The Preparation and Property of Few-Layered Graphene\\/Benzalkonium Chloride Composite  

Microsoft Academic Search

In order to research and development a novel antibacterial material which is used to deal with the drinking water, few-layered grapheme\\/benzalkonium chloride composite was prepared by introducing different content of quaternary ammonium salt into layered graphene, and the resulting composites were characterized by the FTIR, XRD, TGA and TEM. And minimum inhibitory concentration (MIC) was used to investigate antibacterial activity.

Xie A-gui; Cai Xiang; Tan Shao-zao

2010-01-01

251

'Remote' adiabatic photoinduced deprotonation and aggregate formation of amphiphilic N-alkyl-N-methyl-3-(pyren-1-yl)propan-1-ammonium chloride salts.  

PubMed

The absorption and emission properties of a series of amphiphilic N-alkyl-N-methyl-3-(pyren-1-yl)propan-1-ammonium chloride salts were investigated in solvents of different polarities and over a wide concentration range. For example, at 10(-5) M concentrations in tetrahydrofuran (THF), salts with at least one N-H bond exhibited broad, structureless emissions even though time-correlated single photon counting (TCSPC) experiments indicated negligible static or dynamic intermolecular interactions. Salts with a butylene spacer or lacking an N-H bond showed no discernible structureless emission; their emission spectra were dominated by the normal monomeric fluorescence of a pyrenyl group and the TCSPC histograms could be interpreted on the basis of intramolecular photophysics. The broad, structureless emission is attributed to an unprecedented, rapid, adiabatic proton-transfer to the medium, followed by the formation of an intramolecular exciplex consisting of amine and pyrenyl groups. The proposed mechanism involves excitation of a ground-state conformer of the salts in which the ammonium group sits over the pyrenyl ring due to electrostatic stabilization. At higher concentrations, with longer N-alkyl groups, or in selected solvents, electronic excitation of the salts led to dynamic and static excimeric emissions. For example, whereas the emission spectrum of 10(-3) M N-hexyl-N-methyl-3-(pyren-1-yl)propan-1-ammonium chloride in THF consisted of comparable amounts of monomeric and excimeric emission, the emission from 10(-5) M N-dodecyl-N-methyl-3-(pyren-1-yl)propan-1-ammonium chloride in 1:9 (v:v) ethanol/water solutions was dominated by excimeric emission, and discrete particles near micrometer size were discernible from confocal microscopy and dynamic light scattering experiments. Comparison of the static and dynamic emission characteristics of the particles and of the neat solid of N-dodecyl-N-methyl-3-(pyren-1-yl)propan-1-ammonium chloride indicate that molecular packing in the microparticles and in the single crystal are very similar if not the same. It is suggested that other examples of the adiabatic proton transfer found in the dilute concentration regime with the pyrenyl salts may be occurring in very different systems, such as in proteins where conformational constraints hold ammonium groups over aromatic rings of peptide units. PMID:22050478

Abraham, Shibu; Weiss, Richard G

2011-11-03

252

Structural characterization of zinc(II) chloride in aqueous solution and in the protic ionic liquid ethyl ammonium nitrate by x-ray absorption spectroscopy  

NASA Astrophysics Data System (ADS)

Extended x-ray absorption fine structure (EXAFS) spectroscopy has been used to investigate the species and structures existing in a series of ZnCl2-H2O-NaCl solutions with different chloride/zinc ratios and in a solution of ZnCl2 in the protic ionic liquid ethyl ammonium nitrate (EAN). The average coordination numbers and distances of zinc species were determined from the analysis of the EXAFS data. In aqueous solution the number of chloride ions tightly bounded to Zn2+ is significantly related to the chloride/zinc ratio, and no inner complex formation between Zn2+ and Cl- ions has been detected for low ZnCl2 concentration (0.1 and 0.2 M). Conversely, in the same concentration range (0.13 M) the ZnCl2 species do not dissociate in EAN and the Zn2+ first coordination shell has two chloride ions and is completed by two oxygen atoms of the nitrate anion. The results of this investigation show that notwithstanding the existence of similar characteristics between EAN and water, the solvation properties of the two solvents are markedly different.

D'Angelo, Paola; Zitolo, Andrea; Ceccacci, Francesca; Caminiti, Ruggero; Aquilanti, Giuliana

2011-10-01

253

Ionic interactions in aqueous electrolyte-polyelectrolyte mixtures: Comparisons with mixtures of sodium chloride and the model electrolyte benzyltrimethyl-ammonium chloride at 25°C  

Microsoft Academic Search

Osmotic coefficients for aqueous mixtures of sodium chloride with benzyltrimethylammonium chloride, BzMe3NCl, obtained by the gravimetric isopiestic vapor pressure comparison method are interpreted with the McKay-Perring transform, with the Scatchard neutral electrolyte treatment, and with the Pitzer ion-component equations. Molal ionic and mean ionic activity coefficients for Na+ and Cl- ions and for NaCl, respectively, in these mixtures at unit

G. E. Boyd

1977-01-01

254

Enantioselective nucleophilic difluoromethylation of aromatic aldehydes with Me3SiCF2SO2Ph and PhSO2CF2H reagents catalyzed by chiral quaternary ammonium salts  

PubMed Central

Summary Background Although the nucleophilic difluoromethylation of aldehydes, ketones, and imines has been realized with PhSO2CF2H and related reagents, there are still no reports on the enantioselective nucleophilic reactions. Results With a chiral quaternary ammonium salt as the catalyst and KOH as the base, we describe the first enantioselective difluoromethylation of aromatic aldehydes with PhSO2CF2H or Me3SiCF2SO2Ph. The enantioselectivity is substrate-dependent and for 2-chlorinated benzaldehyde an ee up to 64% was obtained. Conclusion These results provide some insights into the enantioselective nucleophilic difluoromethylation chemistry, which will stimulate further progress in this field.

Ni, Chuanfa; Wang, Fang

2008-01-01

255

Performance and mechanism of polyferric-quaternary ammonium salt composite flocculants in treating high organic matter and high alkalinity surface water  

Microsoft Academic Search

A series of composite flocculants PFC–PD with different basicity (B) of polyferric chloride (PFC), different weight percentage (w(P)) and intrinsic viscosity (?) of polydimethyl diallylammonium chloride (PDMDAAC) were prepared by prepolymerization. The turbidity, dissolved organic carbon (DOC) and specific ultraviolet absorbance (SUVA) removal efficiency as well as flocculation mechanism of PFC–PD were compared with that of PFC, PDMDAAC and successive

J. C. Wei; B. Y. Gao; Q. Y. Yue; Y. Wang; L. Lu

2009-01-01

256

Ammonium chloride salting out extraction/cleanup for trace-level quantitative analysis in food and biological matrices by flow injection tandem mass spectrometry.  

PubMed

A sample extraction and purification procedure that uses ammonium-salt-induced acetonitrile/water phase separation was developed and demonstrated to be compatible with the recently reported method for pesticide residue analysis based on fast extraction and dilution flow injection mass spectrometry (FED-FI-MS). The ammonium salts evaluated were chloride, acetate, formate, carbonate, and sulfate. A mixture of NaCl and MgSO4, salts used in the well-known QuEChERS method, was also tested for comparison. With thermal decomposition/evaporation temperature of <350°C, ammonium salts resulted in negligible ion source residual under typical electrospray conditions, leading to consistent method performance and less instrument cleaning. Although all ammonium salts tested induced acetonitrile/water phase separation, NH4Cl yielded the best performance, thus it was the preferred salting out agent. The NH4Cl salting out method was successfully coupled with FI/MS/MS and tested for fourteen pesticide active ingredients: chlorantraniliprole, cyantraniliprole, chlorimuron ethyl, oxamyl, methomyl, sulfometuron methyl, chlorsulfuron, triflusulfuron methyl, azimsulfuron, flupyrsulfuron methyl, aminocyclopyrachlor, aminocyclopyrachlor methyl, diuron and hexazinone. A validation study was conducted with nine complex matrices: sorghum, rice, grapefruit, canola, milk, eggs, beef, urine and blood plasma. The method is applicable to all analytes, except aminocyclopyrachlor. The method was deemed appropriate for quantitative analysis in 114 out of 126 analyte/matrix cases tested (applicability rate=0.90). The NH4Cl salting out extraction/cleanup allowed expansion of FI/MS/MS for analysis in food of plant and animal origin, and body fluids with increased ruggedness and sensitivity, while maintaining high-throughput (run time=30s/sample). Limits of quantitation (LOQs) of 0.01mgkg(-1) (ppm), the 'well-accepted standard' in pesticide residue analysis, were achieved in >80% of cases tested; while limits of detection (LODs) were typically in the range of 0.001-0.01mgkg(-1) (ppm). A comparison to a well-established HPLC/MS/MS method was also conducted, yielding comparable results, thus confirming the suitability of NH4Cl salting out FI/MS/MS for pesticide residue analysis. PMID:23473245

Nanita, Sergio C; Padivitage, Nilusha L T

2013-01-16

257

Headgroup effects on the Krafft temperatures and self-assembly of ?-hydroxy and ?-carboxy hexadecyl quaternary ammonium bromide bolaform amphiphiles: micelles versus molecular clusters?  

PubMed

Eight bolaform amphiphiles were synthesised and characterised; 4 ?,?-hydroxy-alkane trialkyl (and pyridyl) ammonium bromides and 4 ?,?-carboxy-alkane trialkyl (and pyridyl) ammonium bromides where the alkyl groups were methyl, ethyl and propyl. Four of these represented new compounds. Overall the Krafft temperatures (T(K)) of the eight amphiphiles were high, with 6 of the eight possessing T(K)s greater than 45 °C. Thus most of the amphiphiles could only expect to find applications at raised temperatures limiting their potential utility. However in addition to the previously reported ?,?-hydroxy-hexadecyl triethylammonium bromide (2b) with a T(K) of 19.1 °C, another amphiphile, ?,?-carboxy-hexadecyl tripropylammonium bromide (2c) has been identified with a T(K) near ambient temperatures (T(K) of 22.1 °C). This provides an acid functional ammonium bolaform amphiphile that micellises at ambient temperatures to complement the hydroxyl derivative. A correlation between T(K) and the product of the enthalpies and T(m)s of the compounds was observed for 7 of the eight compounds. No correlation between the amphiphile critical micelle concentrations (cmc) and T(K)s was observed confirming previous reports that T(K) values are predominantly determined by crystalline stability rather than solubility. Considerable differences were observed between the various amphiphile T(K)s at different pHs but no clear trend was apparent for the various compounds (despite the degree to which the compounds' carboxylic acid and hydroxyl functionalities were likely to be ionised). The cmcs for the amphiphiles were an order of magnitude larger than those for analogous mono-ammonium amphiphiles with little difference in between the hydroxyl- and carboxy-functionalised compounds. The aggregation numbers (N(agg)) obtained for all compounds were very low (N(agg)<7) and the apparent micellar diameters for the hydroxyl-bolaforms were in the range 1.0-1.4 nm whereas those for the carboxy-compounds were in the range 2.1-2.4 nm. These results strongly suggest a difference in the packing of the two sets of amphiphiles with loose low density aggregates or 'molecular clusters' for the carboxy compounds and denser classical micellar type aggregates for the hydroxyl-compounds. In both cases however the sizes and the low aggregation numbers point suggest that these aggregates are more characteristic of the pre-micellar aggregates observed for many amphiphiles but in particular gemini surfactants. PMID:22137856

Holder, Simon J; Sriskantha, Bruntha C; Bagshaw, Stephen A; Bruce, Ian J

2011-11-10

258

The effect of cetylpyridinium chloride on halitosis and periodontal disease-related parameters in dogs  

Microsoft Academic Search

Periodontal disease is an oral disease common in middle-aged dogs and cats, with halitosis being the most common sign. There\\u000a are many commercial products containing chlorhexidine, cetylpyridinium chloride (CPC), zinc salts and essential oils for controlling\\u000a halitosis and periodontal disease. CPC is a quaternary ammonium compound and has a broad spectrum antimicrobial activity.\\u000a In this study, oral spray (OS) and

Se Eun Kim; Kyung Mi Shim; Kyeong Hoon Yoo; Jong-Choon Kim; Sung-Ho Kim; Chun-Sik Bae; Doman Kim; Don Hee Park; Ji-Won Ryu; Seong Soo Kang

2008-01-01

259

pH responsive properties of non-fouling mixed-charge polymer brushes based on quaternary amine and carboxylic acid monomers  

Microsoft Academic Search

In this work, we report a tunable mixed-charge copolymer surface containing positively charged quaternary amine monomers ([2-(Acryloyloxy)ethyl] trimethyl ammonium chloride, TMA) and negatively-charged carboxylic acid monomers (2-carboxy ethyl acrylate, CAA). The non-fouling properties of this copolymer coating depend on environmental pH. The surface has charge neutrality under neutral and basic conditions, and is positively charged under acidic conditions due to

Luo Mi; Matthew T. Bernards; Gang Cheng; Qiuming Yu; Shaoyi Jiang

2010-01-01

260

CEC separation of peptides using a poly(hexyl acrylate-co-1,4-butanediol diacrylate-co-[2-(acryloyloxy)ethyl]trimethyl ammonium chloride) monolithic column.  

PubMed

A polyacrylate-based monolithic column bearing cationic functionalities and designed for capillary electrochromatography (CEC) has been prepared via photopolymerization of a mixture of hexyl acrylate, butanediol diacrylate, 2-(acryloyloxy) ethyltrimethyl ammonium chloride (monomers), azobisisobutyronitrile (photoinitiator), acetonitrile, phosphate buffer, and ethanol (porogens). The polymerization process was initiated with UV light at 360 nm. The column performance was evaluated via the separations of alkylbenzenes, substituted anilines, basic drugs, peptides, and a protein digest. The separation of complex peptide mixtures was then studied since such separations constitute a promising application of capillary electrochromatography. In particular, the effects of mobile phase composition, including ionic strength of the buffer solution and the percentage of acetonitrile on the retention factor, the column efficiency, and the resolution were determined. The separations were affected by both interaction of the peptides with the stationary phase and their own electrophoretic mobility. Excellent separations with column efficiencies of up to 160 000 plates/m were achieved for both a mixture of ten well-defined peptides and a tryptic digest of cytochrome c. The fractions of eluent containing peptides of the digest separated in the monolithic column were collected and characterized using matrix-assisted laser desorption ionization mass spectrometry. PMID:18850656

Augustin, Violaine; Stachowiak, Timothy; Svec, Frantisek; Fréchet, Jean M J

2008-09-01

261

Column preconcentration of gold by adsorbing AuCl4- onto methyltrioctyl ammonium chloride-naphthalene and subsequent atomic absorption spectrometric determination.  

PubMed

A sensitive, selective and simple preconcentration method for ultra-trace gold determination has been developed that uses naphthalene-methyltrioctyl ammonium chloride (Aliquat 336s) as an adsorbent. Gold, in the form of AuCl4-, was retained by the adsorbent in the column at a flow rate of 1 ml min(-1). After filtration, the solid mass consisting of the gold complex and naphthalene was dissolved out of the column with 5 ml of N,N-dimethylformamide (DMF), and the metal was then determined by atomic absorption spectrometry. In the initial solution, the calibration graph of absorbance versus gold concentration was found to be linear in the range 0.5-150 ng ml(-1) Au(III) with r=0.997 (n=9), and the 3 s detection limit was 0.428 ng ml(-1). The relative standard deviation for eight replicate measurements of 20 microg of gold was 2.14%. Preconcentration factors of 390 and 650 were achieved using 5 ml and 3 ml of DMF, respectively. The proposed method was successfully applied to the determination of gold in wastewater, processed pool water, slurry pool water, and raw well-water from the Moteh gold mine, and synthetic samples. PMID:15838616

Behpour, M; Attaran, A M; Ghoreishi, S M; Soltani, N

2005-04-19

262

High mass accuracy in-source collision-induced dissociation tandem mass spectrometry and multi-step mass spectrometry as complementary tools for fragmentation studies of quaternary ammonium herbicides.  

PubMed

Fragmentation studies using both an ion-trap mass analyzer and a hybrid quadrupole time-of-flight (Q-TOF) mass spectrometer were performed in order to establish the fragmentation pathways of organic molecules. A general strategy combining MSn data (n = 1-4) in an ion-trap analyzer with tandem mass spectrometry and in-source collision-induced dissociation tandem mass spectrometry (CID MS/MS) in a Q-TOF instrument was applied. The MSn data were used to propose a tentative fragmentation pathway following genealogical relationships. When several assignments were possible, MS/MS and in-source CID MS/MS (Q-TOF) allowed the elemental compositions of the fragments to be confirmed. Quaternary ammonium herbicides (quats) were used as test compounds and their fragmentation pathways were established. The elemental composition of the fragments was confirmed using the TOF analyzer with relative errors <0.0023 Da. Some fragments previously reported in the literature were reassigned taking advantage of the high mass resolution and accuracy of the Q-TOF instrument, which made it possible to solve losses where nitrogen was involved. PMID:15329839

Núñez, Oscar; Moyano, Encarnación; Galceran, Maria Teresa

2004-08-01

263

Analysis of quaternary ammonium compounds in estuarine sediments by LC-ToF-MS: very high positive mass defects of alkylamine ions provide powerful diagnostic tools for identification and structural elucidation  

PubMed Central

A sensitive and robust method of analysis for quaternary ammonium compounds (QACs) in marine sediments is presented. Methods for extraction, sample purification, and HPLC-Time-of-Flight-MS analysis were optimized, providing solutions to problems associated with analysis of QACs, such as dialkyldimethylammonium (DADMAC) and benzalkonium (BAC) compounds experienced previously. Recognized in this study are the exceptionally high positive mass defects characteristic of alkylammonium or protonated alkylamine ions. No alternative and chemically-viable elemental formulas exist within 25.2 mDa when the number of double bond equivalents is low, effectively allowing facile discrimination of this compound class in complex mixtures. Accurate mass measurements of diagnostic collision induced dissociation fragment ions and heavy isotope peaks were obtained and also seen to be uniquely heavy compared to other elemental formulae. In the case of BACs, the ability to resolve masses of alkylamine fragment ions is greater than it is for molecular ions, opening up a wide range of potential applications. The power of utilizing a combination of approaches is illustrated with the identification of non-targeted DADMAC C8:C8 and C8:C10, two widely used biocides previously unreported in environmental samples. Concentrations of QACs in sewage-impacted estuarine sediments (up to 74 ?g/g) were higher than concentrations of other organic contaminants measured in the same or nearby samples, suggesting further study is needed.

Li, Xiaolin; Brownawell, Bruce J.

2009-01-01

264

[Antimicrobial action of ammonium salts of fused heterocycles containing ortho-nitrogen].  

PubMed

By alkylation of hexamethylenetetramine with halogenated derivatives of ketones, ethers, esters or amides of acids, alkyl- and aralkyl halides the corresponding N-monoalkylated compounds of hexamethylenetetramine were obtained. The quaternization of pyridine nitrogen in 5,6-benzoquinoline, 8-hydroxyquinoline, quinoline, 1,10-phenanthroline molecules with alkyl- or aralkylhalides was carried out. The susceptibility of Gram-positive (Streptococcus agalactiae and Staphylococcus aureus) and Gram-negative (E. coli, Salmonella cholerae suis, Salmonella enteridis Gartneri) microorganisms to synthesized quaternary ammonium salts by disc difussion method has been detected. The bacteriostatic action of 0.5-1% solutions of all compounds was assessed in comparison with benzalkonium chloride. It was shown, that the most effectiveness against all strains is possessed by quaternary hexamethylenetetramine ammonium salts, and especially salts, containing 1-propynyl- or hydroxycarbamoylmethyl radicals. The action of these two compounds against Salmonella and Streptococcus was stronger than the action of benzalkonium chloride. Susceptibility of Pseudomonas aeruginosa to these compounds were detected. It was shown, that 1% solutions of chlorides of N-(1-propynyl) hexamethylenetetramonium and N-(hydroxycarbamoylmethyl) hexamethylenetetrammonium demonstrate the same bacteriostatic action against P. aeruginosa as well as benzalkonium chloride. PMID:14617863

Stankeviciene, Laimute; Grigonis, Aidas; Matusevicius, Algimantas; Janusiene, Laima; Stankevicius, Antanas

2003-01-01

265

Calibration and measurement uncertainties of a continuous-flow cloud condensation nuclei counter (DMT-CCNC): CCN activation of ammonium sulfate and sodium chloride aerosol particles in theory and experiment  

Microsoft Academic Search

Experimental and theoretical uncertainties in the measurement of cloud condensation nuclei (CCN) with a continuous-flow thermal-gradient CCN counter from Droplet Measurement Technologies (DMT-CCNC) have been assessed by model calculations and calibration experiments with ammonium sulfate and sodium chloride aerosol particles in the diameter range of 20-220 nm. Experiments have been performed in the laboratory and during field measurement campaigns, covering

D. Rose; S. S. Gunthe; E. Mikhailov; G. P. Frank; U. Dusek; M. O. Andreae; U. Pöschl

2008-01-01

266

Quaternary ammonium room-temperature ionic liquid including an oxygen atom in side chain/lithium salt binary electrolytes: ab initio molecular orbital calculations of interactions between ions.  

PubMed

Interactions of the lithium bis(trifluoromethylsulfonyl)amide (LiTFSA) complex with N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium (DEME), 1-ethyl-3-methylimidazolium (EMIM) cations, neutral diethylether (DEE), and the DEMETFSA complex were studied by ab initio molecular orbital calculations. An interaction energy potential calculated for the DEME cation with the LiTFSA complex has a minimum when the Li atom has contact with the oxygen atom of DEME cation, while potentials for the EMIM cation with the LiTFSA complex are always repulsive. The MP2/6-311G**//HF/6-311G** level interaction energy calculated for the DEME cation with the LiTFSA complex was -18.4 kcal/mol. The interaction energy for the neutral DEE with the LiTFSA complex was larger (-21.1 kcal/mol). The interaction energy for the DEMETFSA complex with LiTFSA complex is greater (-23.2 kcal/mol). The electrostatic and induction interactions are the major source of the attraction in the two systems. The substantial attraction between the DEME cation and the LiTFSA complex suggests that the interaction between the Li cation and the oxygen atom of DEME cation plays important roles in determining the mobility of the Li cation in DEME-based room temperature ionic liquids. PMID:18636771

Tsuzuki, Seiji; Hayamizu, Kikuko; Seki, Shiro; Ohno, Yasutaka; Kobayashi, Yo; Miyashiro, Hajime

2008-07-18

267

Corrosion inhibition by quaternary amines  

Microsoft Academic Search

Quaternary ammonium compounds are excellent inhibitors of acid corroison, and seem to influence the anodic partial reaction more than the cathodic. This behavior is not readily interpreted in terms of physical vs. chemical adsorption, since these compounds do not possess bonding for chemisorption. Increasing the hydrogen bulk in the inhibitor molecule markedly increases the inhibition efficiency, which is to be

R. M. Hurd; H. Raiszadeh

1970-01-01

268

Vinylbenzyl quaternary ammonium-based polymeric monolith with hydrophilic interaction/strong anion exchange mixed-mode for pressurized capillary electrochromatography.  

PubMed

A novel polymeric monolith with hydrophilic interaction and strong anion-exchange mixed-mode has been fabricated for pressurized capillary electrochromatography by an in situ copolymerization of vinylbenzyl trimethylammonium chloride (VBTA) and bisphenol A glycerolate dimethacrylate (BisGMA). The optimization of the polymerization mixture composition has been investigated, and column characteristics in terms of mechanical stability, permeability and reproducibility have been studied in detail. Linear responses between back pressure and flow rate have been achieved in different solvents. The absolute value of swelling propensity (SP) factor for poly(VBTA-co-BisGMA) monolith is 0.41, and the degree of permeability drop from pure ACN to water is about 45%. An acceptable mechanical stability of the column is obtained. The suitable reproducibility is also measured with the RSD for day-to-day (n=3) of retention time and column efficiency less than 3.3%, and the RSD for batch-to-batch (n=3) less than 5.3%, respectively. Under the optimum conditions, the mixed-mode of hydrophilic interaction and strong anion-exchange has been carried out, and efficient electrochromatography profiling of various polar compounds including neutral phenols, negatively charged benzoic acids and positively charged nucleic acid bases and nucleosides are achieved, respectively. PMID:24125728

Lin, Xucong; Feng, Shuhui; Jia, Wenchao; Ding, Kang; Xie, Zenghong

2013-10-05

269

Functionalization of cotton fabrics by radiation induced grafting of quaternary salt to impart antibacterial property  

NASA Astrophysics Data System (ADS)

High energy gamma radiation has been used to covalently link polymer chains of a quaternary ammonium salt containing monomer, viz. [2-(Acryloyloxyethyl)]trimethylammonium chloride (AETC) to cotton fabric by mutual radiation grafting using 2-hydroxyethyl methacrylate (2-HEMA) monomer as the grafting facilitator. Grafting yield was found to increase with the radiation dose and monomer concentration. The grafted samples have been characterized for water uptake, surface morphology and thermal stability and for their antibacterial efficacy against various bacteria and were found to possess significant antibacterial activity particularly against gram-positive bacteria.

Goel, N. K.; Kumar, Virendra; Rao, M. S.; Bhardwaj, Y. K.; Sabharwal, S.

2011-11-01

270

Benzalkonium chloride. Health hazard evaluation report  

SciTech Connect

Health hazards associated with the use of benzalkonium chlorides (BAC) are reviewed. Benzalkonium chloride is extensively used as a cationic disinfectant. It is found in a great many over-the-counter and prescription eye products, disinfectants, shampoos, and deodorants, and is used in concentrations that range from 0.001 to 0.01% in eyedrops, up to 2.5% in concentrated liquid disinfectants. Solutions of 0.03 to 0.04% BAC may cause temporary eye irritation in humans but are unlikely to cause any skin response except in persons allergic to quaternary ammonium compounds. Inhalation of a vaporized 10% solution of BAC produced a bronchospasmodic reaction in a previously sensitized individual. At present no other human health effects from BAC have been documented or inferred from exposure to such dilute concentrations.

Bernholc, N.M.

1984-01-01

271

Determination of oxybutinin chloride in pharmaceuticals by reversed-phase ion-pair liquid chromatography with two counter-ions in the eluent.  

PubMed

A reliable stability-indicating method using reversed-phase ion-pair high-performance liquid chromatography for the determination of the anticholinergic drug oxybutinin chloride in pharmaceuticals is reported. Sample extraction is easy and fairly rapid and recovery and precision of the method are excellent. Due to the simultaneous use of an organic amine and of an alkanesulphonate in the mobile phase, good selectivity towards related (quaternary ammonium) anticholinergic drugs was obtained. PMID:3241019

De Schutter, J A; De Moerloose, P

1988-10-26

272

Quaternary investigation  

SciTech Connect

The primary purpose of the Quaternary investigation is to provide information on the location and age of Quaternary deposits for use in evaluating the presence or absence of neotectonic deformation or paleoliquefaction features within the Savannah River Site (SRS) region. The investigation will provide a basis for evaluating the potential for capable faults and associated deformation in the SRS vicinity. Particular attention will be paid to the Pen Branch fault.

Stieve, A.

1991-05-15

273

Methyl chloride via oxhydrochlorination of methane  

SciTech Connect

Dow Corning is developing a route from methane to methyl chloride via oxyhydrochlorination (OHC) chemistry with joint support from the Gas Research Institute and the Department of Energy Federal Energy Technology Center. Dow Corning is the world`s largest producer of methyl chloride and uses it as an intermediate in the production of silicone materials. Other uses include production of higher hydrocarbons, methyl cellulose, quaternary ammonium salts and herbicides. The objective of this project is to demonstrate and develop a route to methyl chloride with reduced variable cost by using methane instead of methanol raw materials. Methyl chloride is currently produced from methanol, but U.S. demand is typically higher than available domestic supply, resulting in fluctuating prices. OHC technology utilizes domestic natural gas as a feedstock, which allows a lower-cost source of methyl chloride which is independent of methanol. In addition to other uses of methyl chloride, OHC could be a key step in a gas-to-liquid fuels process. These uses could divert significant methanol demand to methane. A stable and selective catalyst has been developed in the laboratory and evaluated in a purpose-built demonstration unit. Materials of construction issues have been resolved and the unit has been run under a range of conditions to evaluate catalyst performance and stability. Many technological advances have been made, especially in the areas of catalyst development, online FTIR analysis of the product stream, and recovery of methyl chloride product via an absorber/stripper system. Significant technological hurdles still remain including heat transfer, catalysts scaleup, orthogonality in modeling, and scaleable absorption data. Economics of the oxyhydrochlorination process have been evaluated an found to be unfavorable due to high capital and utility costs. Future efforts will focus on improved methane conversion at high methyl chloride selectivity.

Jarvis, R.F. Jr.

1997-12-31

274

Method for the abatement of hydrogen chloride  

DOEpatents

The present invention provides a method for reducing the amount of hydrogen chloride contained in a gas stream by reacting the hydrogen chloride with ammonia in the gas phase so as to produce ammonium chloride. The combined gas stream is passed into a condensation and collection vessel and a cyclonic flow is created in the combined gas stream as it passes through the vessel. The temperature of the gas stream is reduced in the vessel to below the condensation temperature of ammonium chloride in order to crystallize the ammonium chloride on the walls of the vessel. The cyclonic flow creates a turbulence which breaks off the larger particles of ammonium chloride which are, in turn, driven to the bottom of the vessel where the solid ammonium chloride can be removed from the vessel. The gas stream exiting from the condensation and collection vessel is further cleaned and additional ammonium chloride is removed by passing through additional filters.

Winston, Steven J. (Idaho Falls, OH); Thomas, Thomas R. (Idaho Falls, OH)

1977-01-01

275

Method for the abatement of hydrogen chloride  

DOEpatents

A method is described for reducing the amount of hydrogen chloride contained in a gas stream by reacting the hydrogen chloride with ammonia in the gas phase so as to produce ammonium chloride. The combined gas stream is passed into a condensation and collection vessel, and a cyclonic flow is created in the combined gas stream as it passes through the vessel. The temperature of the gas stream is reduced in the vessel to below the condensation temperature of ammonium chloride in order to crystallize the ammonium chloride on the walls of the vessel. The cyclonic flow creates a turbulence which breaks off the larger particles of ammonium chloride which are, in turn, driven to the bottom of the vessel where the solid ammonium chloride can be removed from the vessel. The gas stream exiting from the condensation and collection vessel is further cleaned and additional ammonium chloride is removed by passing through additional filters.

Winston, S.J.; Thomas, T.R.

1975-11-14

276

Highly enantioselective chlorination of ?-keto esters and subsequent S(N)2 displacement of tertiary chlorides: a flexible method for the construction of quaternary stereogenic centers.  

PubMed

Highly enantioselective chlorination of ?-oxo esters and subsequent stereospecific substitution of tertiary chlorides are described. Enantioselective chlorination of ?-keto esters and malonates was performed using a chiral Lewis acid catalyst prepared from Cu(OTf)(2) and the newly developed spirooxazoline ligand 2 to yield the desired ?-chlorinated products with high enantioselectivity (up to 98% ee). Nucleophilic substitution of the resulting chlorides proceeded smoothly to afford a variety of chiral molecules such as ?-amino, ?-alkylthio, and ?-fluoro esters, without loss of enantiopurity. The results of X-ray crystallographic analysis proved that Walden inversion occurs at the chlorinated tertiary carbon center. These results supported the fact that the substitution proceeds via an S(N)2 mechanism. PMID:22651700

Shibatomi, Kazutaka; Soga, Yoshinori; Narayama, Akira; Fujisawa, Ikuhide; Iwasa, Seiji

2012-06-06

277

Preparation of Anhydrous Magnesium Chloride from Magnesium Chloride Hexahydrate  

NASA Astrophysics Data System (ADS)

A method was proposed for the preparation of high-purity anhydrous magnesium chloride by using magnesium chloride hexahydrate and ammonium chloride as raw materials, and alumina as covering agent. X-ray diffraction was employed to investigate the process. The mechanism involved in the process was proposed. The factors affecting the purity of anhydrous magnesium chloride were investigated. Dehydrated ammonium carnallite was formed in the process to facilitate the dehydration process. Alumina as covering agent can guarantee that the formation of high-purity anhydrous magnesium chloride was obtained. The content of magnesia in anhydrous magnesium chloride was 0.02 pct under the optimum conditions: molar ratio of ammonium chloride to dehydrated magnesium chloride was 2:1, thickness of alumina 1.3 cm, reaction temperature 723 K (450 °C), reaction time 1 hour, and the number of crystallized water 0.6 to 2.2.

Zhang, Zhimin; Lu, Xuchen; Pan, Feng; Wang, Yun; Yang, Suping

2013-04-01

278

Adsorption of some quaternary onium salts on silica gel  

Microsoft Academic Search

The adsorption of quaternary onium salts such as hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, benzyltrimethylammonium chloride and tetrabutylammonium bromide from aqueous solution, and of tricaprylylmethylammonium chloride (Aliquat® 336) and hexadecyltributyl phosphonium bromide from organic solution has been studied using silica as an adsorbent. The adsorption from the aqueous phase was found to be dependent on the pH of the medium, giving a

A. C. Ghosh; K. Satyanarayana; R. C. Srivastava; N. N. Dutta

1995-01-01

279

Interaction of polyquaternary ammonium salt and persulfate  

Microsoft Academic Search

An interaction between poly(diallyldimethylammonium chloride) and ammonium persulfate in aqueous solutions has been detected and studied by methods of turbidimetry and viscometry. Investigations were carried out with the cationic polymer of different molecular weight. It was shown that association between low-molecular-weight polyquaternary ammonium salt polycations and persulfate anions was predominant over the chemical (redox) reaction with counterions Cl –. Appreciably

Edita Mazoniene; RimaJule Zemaitaitiene; Gintaras Buika; Algirdas Zemaitaitis

2004-01-01

280

The Alaska Quaternary Center  

NSDL National Science Digital Library

This website illustrates the Alaska Quaternary Center's (at the University of Alaska, Fairbanks) commitment "to the promotion of interdisciplinary research and the enhancement of interdisciplinary instruction in Quaternary sciences." Users can view images of the field work and learn how to obtain quaternary data from the AQC Quaternary Research Geodatabase.

1969-12-31

281

Irish Quaternary Association (IQUA)  

NSDL National Science Digital Library

The Irish Quaternary Association (IQUA) website publicizes its aim "to promote Quaternary studies in Ireland through its publications, and the organization of field meetings and conferences." Visitors can learn about the importance of quaternary studies, find out the latest news and upcoming meetings, and find links to Quaternary studies journals.

1969-12-31

282

Effect of chemical sanitizers with and without ultrasonication on Listeria monocytogenes as a biofilm within polyvinyl chloride drain pipes.  

PubMed

As part of a biofilm in a floor drain, Listeria monocytogenes is exceedingly difficult to eradicate with standard sanitizing protocols. The objective of these studies was to test the use of ultrasonication to break up biofilm architecture and allow chemical sanitizers to contact cells directly. L. monocytogenes biofilms were created in model polyvinyl chloride drain pipes. Chemical sanitizers (quaternary ammonium, peroxide, or chlorine) were applied to the drain pipes with and without a 30-s ultrasonication treatment. Controls using sterile water were included for comparison. L. monocytogenes cells were enumerated from the liquid in the drain and the inside wall surface of the pipe. All chemicals lowered numbers of planktonic cells from 6.6 log CFU/ml in the water control to < 100 CFU/ml. Attached cells were also affected by the chemical sanitizers. Approximately 6.0 log CFU/cm2 of the inner wall surface was detected in water control pipes, and ultrasonication did not lower these numbers. With or without ultrasonication, the peroxide-based sanitizer was effective for reducing the numbers of attached L. monocytogenes cells, resulting in approximately 2.0 log CFU/cm2. Both the chlorine- and quaternary ammonium-based sanitizers reduced the number of attached L. monocytogenes cells to a lesser degree, resulting in 4.2 to 4.4 log CFU/cm2. However, addition of ultrasonication improved the performance of both these sanitizers, causing a further reduction to 3.1 and 2.9 CFU/ cm2 for quaternary ammonium- and chlorine-based chemicals, respectively. These results indicate that a peroxide-based sanitizer alone can be very effective against biofilm L. monocytogenes in drain pipes, and the addition of ultrasonication can improve the effectiveness of chlorine or quaternary ammonium sanitizers. PMID:18236664

Berrang, M E; Frank, J F; Meinersmann, R J

2008-01-01

283

The structure and composition of surfactant-polymer mixtures of sodium dodecyl sulphate, hexaethylene glycol monododecyl ether and poly-(dimethyldialyl ammonium chloride) adsorbed at the air-water interface  

NASA Astrophysics Data System (ADS)

Specular neutron reflection has been used to investigate the composition and structure of the surfactant-polymer mixture of sodium dodecyl sulphate (SDS) and hexaethylene glycol monododecyl ether (C12E6), and the cationic polymer poly-(dimethyldialyl ammonium chloride) (dmdaac), at the air-water interface. In particular, the effects of surfactant and polymer concentration are investigated. The addition of the cationic polymer results in an interface more rich in SDS. The variation of surfactant composition with polymer and surfactant concentration shows a complex behaviour, which is related indirectly to the bulk solution phase behaviour. The amount of polymer at the interface increases with increasing polymer concentration, but decreases with increasing surfactant concentration at a fixed solution polymer concentration. At a polymer concentration ~100 ppm there is a marked change in the structure of the adsorbed polymer layer: the thickness of the absorbed layer increases from ~20 Å to ~30 Å. In contrast the thickness of the absorbed layer, when only the surfactant is visible at the interface, shows no significant change with increasing polymer concentration.

Staples, E.; Tucker, I.; Penfold, J.; Warren, N.; Thomas, R. K.

2000-07-01

284

40 CFR Table 2 to Subpart B of... - MON Source Categories  

Code of Federal Regulations, 2010 CFR

...Resins Production. Polymerized Vinylidene Chloride Production. Polymethyl Methacrylate Resins... Quaternary Ammonium Compounds Production. Benzyltrimethylammonium Chloride Production. Carbonyl Sulfide...

2009-07-01

285

40 CFR Table 2 to Subpart B of... - MON Source Categories  

Code of Federal Regulations, 2010 CFR

...Resins Production. Polymerized Vinylidene Chloride Production. Polymethyl Methacrylate Resins... Quaternary Ammonium Compounds Production. Benzyltrimethylammonium Chloride Production. Carbonyl Sulfide...

2010-07-01

286

The size of hydroxyl groups in solution and the changes in size associated with the ionization of phenolic, carboxylic and amino groups in phenolic quaternary ammonium salts, nicotine and some amino acids: possible implications for drug-water and drug-receptor interactions.  

PubMed Central

Size in solution can be expressed either as the apparent molal volume at infinite dilution (phi 0v) amd the concentration parameter (j) or as the partial molal volume of the solute at infinite dilution (V0(2)) and the concentration parameter for the solute or solvent (qs or qw). Although calculated differently, these are derived from the same results and are equivalent. From measurement with phenolic quaternary ammonium salts, including compounds with high nicotine-like activity, the apparent size of the hydroxyl group in water is small and variable. Phenolic groups are slightly larger than alcoholic groups, which should be better hydrogen donors. By measuring the volume change associated with ionisation it is possible to measure the size of charged groups such as phenate and carboxylate; these are much smaller than phenolic and carboxyl. Ammonium groups, however, are only slightly smaller than the corresponding amines. The zwitterion forms of amino acids are associated with a minimum in volume but the volume changes increase with chain length from glycine to gamma-aminobutyric acid. Groups separated by less than this distance interact in their effects on water. Decreases in volume or unexpectedly small increments in apparent molal volume represent decreases in entropy which must be taken into account in drug-water-receptor interactions. Although they may be offset by enthalpy changes, they should favour binding because there is more scope for an increase in entropy. This might explain the association of the small apparent size in water of the hydroxyl group in many compounds with its effects of their affinity for receptors.

Barlow, R. B.

1980-01-01

287

(1-Naphthyl-meth-yl)ammonium chloride  

PubMed Central

The reaction of 1-naphthyl­methyl­amine and hydro­chloric acid in a 1:1 molar ratio resulted in the formation of the 1:1 proton-transfer compound, C11H12N+·Cl?. In the crystal, the ions are linked by N—H?Cl hydrogen bonds into a sheet pattern in the ab plane such that each Cl? ion is bonded to three NH groups from the naphthylmethylammonium ion.

Salimi, Ali R.; Azizpoor Fard, Mahmood; Eshtiagh-Hosseini, Hossein; M. Amini, Mostafa; Khavasi, Hamid R.

2010-01-01

288

Hydration effects in quaternary amine extraction systems  

Microsoft Academic Search

The extraction of Al+++, Cd++, Co++, Cu+, Cu++, Fe++, Fe+++, In+++, Ni++, and Zn++ with quaternary amine was studied using chloride and sulfate as ligands. On the basis of loading experiments and slope analyses, the species extracted were: CdCl{4\\/=}, CoCl{4\\/=}, CuCl{2\\/-}, CuCl{4\\/=}, FeCl{4\\/-}, and ZnCl{4\\/=}. Water content of the organic phase was analyzed as a function of loading by Karl

J. D. Miller; M. C. Fuerstenau

1970-01-01

289

Hydration effects in quaternary amine extraction systems  

Microsoft Academic Search

The extraction of Al+++, Cd++, Co++, Cu+, Cu++, Fe++, Fe+++, In+++, Ni++, and Zn++ with quaternary amine was studied using chloride and sulfate as ligands. On the basis of loading experiments and slope analyses,\\u000a the species extracted were: CdCl4=, CoCl4=, CuCl2?, CuCl4=, FeCl4?, and ZnCl4=. Water content of the organic phase was analyzed as a function of loading by Karl

J. D. Miller; M. C. Fuerstenau

1970-01-01

290

Calibration and measurement uncertainties of a continuous-flow cloud condensation nuclei counter (DMT-CCNC): CCN activation of ammonium sulfate and sodium chloride aerosol particles in theory and experiment  

NASA Astrophysics Data System (ADS)

Experimental and theoretical uncertainties in the measurement of cloud condensation nuclei (CCN) with a continuous-flow thermal-gradient CCN counter from Droplet Measurement Technologies (DMT-CCNC) have been assessed by model calculations and calibration experiments with ammonium sulfate and sodium chloride aerosol particles in the diameter range of 20-220 nm. Experiments have been performed in the laboratory and during field measurement campaigns, covering a wide range of instrument operating conditions (650-1020 hPa pressure, 293-303 K inlet temperature, 4-34 K m-1 temperature gradient, 0.5-1.0 L min-1 flow rate). For each set of conditions, the effective water vapor supersaturation (Seff, 0.05-1.4%) was determined from the measured CCN activation spectra (dry particle activation diameters) and Köhler model calculations. High measurement precision was achieved under stable laboratory conditions, where the relative standard deviations of Seff were as low as ±1%. During field measurements, however, the relative deviations increased to about ±5%, which can be mostly attributed to variations of the CCNC column top temperature with ambient temperature. The observed dependence of Seff on temperature, pressure, and flow rate was compared to the CCNC flow model of Lance et al. (2006). At high Seff the relative deviations between flow model and experimental results were mostly less than 10%, but at Seff?0.1% they exceeded 40%. Thus, careful experimental calibration is required for high-accuracy CCN measurements - especially at low Seff. A comprehensive comparison and uncertainty analysis of the various Köhler models and thermodynamic parameterizations commonly used in CCN studies showed that the relative deviations between different approaches are as high as 25% for (NH4)2SO4 and 12% for NaCl. The deviations were mostly caused by the different parameterizations for the activity of water in aqueous solutions of the two salts. To ensure comparability of results, we suggest that CCN studies should always report exactly which Köhler model equations and parameters were used. Provided that the Aerosol Inorganics Model (AIM) can be regarded as an accurate source of water activity data for highly dilute solutions of (NH4)2SO4 and NaCl, only Köhler models that are based on the AIM or yield similar results should be used in CCN studies involving these salts and aiming at high accuracy. Experiments with (NH4)2SO4 and NaCl aerosols showed that the conditions of particle generation and the shape and microstructure of NaCl particles are critical for their application in CCN activation experiments (relative deviations up to 18%).

Rose, D.; Gunthe, S. S.; Mikhailov, E.; Frank, G. P.; Dusek, U.; Andreae, M. O.; Pöschl, U.

2008-02-01

291

Salmonella enterica Strains with Reduced Susceptibility to Quarternary Ammonium Compounds  

Technology Transfer Automated Retrieval System (TEKTRAN)

Background: Salmonella spp. are responsible for 76 million illnesses per year in the U.S. Quaternary ammonium compounds (QAC) are commonly used antimicrobial agents. Reduced susceptibility to these compounds by a broad spectrum of organisms is a concern. Methods: Salmonella enterica strains with r...

292

Removal of Ammonium from Tannery Wastewater by Electrochemical Treatment  

Microsoft Academic Search

The removal of ammonium from coagulated tannery wastewaters was investigated by an electrochemical method using Ti\\/IrO2 as an anode. Operating variables including the current density, pH and chloride concentration were considered in order to determine their effect on the ammonium removal efficiency. A maximum ammonium removal rate of 78.9% was achieved after 30 min of electrochemical treatment with 4 A dm of current

Kyung-Sok Min; Jae-Jeong Yu; Young-Ju Kim; Zuwhan Yun

2004-01-01

293

Second Quaternary dating workshop.  

National Technical Information Service (NTIS)

The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies...

1999-01-01

294

Bactericidal mixture of sulfite salt and surfactant quaternary ammonium salt  

Microsoft Academic Search

Fluid drive oil recovery processes which use an aqueous liquid are commonly faced with a problem in the control of both aerobic bacteria and anaerobic bacteria in the waters or aqueous liquids utilized for injection. The presence of anaerobic bacteria, such as the sulfate-reducing bacteria, is of primary concern, because of the metal corrosion, formation plugging, and possible hydrogen sulfide

C. F. Blankenhorn; T. S. Felmann

1973-01-01

295

Quaternary ammonium borohydride adsorption in mesoporous silicate MCM-48  

SciTech Connect

Inorganic borohydrides have a high gravimetric hydrogen density but release H2 only under energetically unfavorable conditions. Surface chemistry may help in lowering thermodynamic barriers, but inclusion of inorganic borohydrides in porous silica materials has proved hitherto difficult or impossible. We show that borohydrides with a large organic cation are readily adsorbed inside mesoporous silicates, particularly after surface treatment. Thermal analysis reveals that the decomposition thermodynamics of tetraalkylammonium borohydrides are substantially affected by inclusion in MCM-48. Inelastic neutron scattering (INS) data show that the compounds adsorb on the silica surface. Evidence of pore loading is supplemented by DSC/TGA, XRD, FTIR, and BET isotherm measurements. Mass spectrometry shows significant hydrogen release at lower temperature from adsorbed borohydrides in comparison with the bulk borohydrides. INS data measured for partially decomposed samples indicates that the decomposition of the cation and anion is likely simultaneous. Additionally, these data confirm the formation of Si-H bonds on the silica surface upon decomposition of adsorbed tetramethylammonium borohydride.

Wolverton, Michael J [Los Alamos National Laboratory; Daemen, Luke L [Los Alamos National Laboratory; Hartl, Monika A [Los Alamos National Laboratory

2010-01-01

296

Insensitive Ammonium Nitrate.  

National Technical Information Service (NTIS)

The danger of the accidental detonation of large masses of commercial ammonium nitrate during handling and storage under normal climatic conditions is reduced by replacing the ammonium nitrate with a solid solution of potassium nitrate in form III ammoniu...

C. Boyars

1978-01-01

297

Characterization of â??the quaternary amine transporters of Rhizobium leguminosarum bv. viciae 3841  

Microsoft Academic Search

Rhizobium leguminosarum bv. viciae 3841 contains six putative quaternary ammonium transporters (Qat), of the ABC family. Qat6 was strongly induced by hyperosmosis although the solute transported was not identified. All six systems were induced by the quaternary amines choline and glycine betaine. It was confirmed by microarray analysis of the genome that pRL100079-83 (qat6) is the most strongly upregulated transport

Marc A. Fox; Ramakrishnan Karunakaran; Mary E. Leonard; Bouchra Mouhsine; Allan Williams; Alison K. East; J. Allan Downie; Philip S. Poole

2008-01-01

298

Calibration and measurement uncertainties of a continuous-flow cloud condensation nuclei counter (DMT-CCNC): CCN activation of ammonium sulfate and sodium chloride aerosol particles in theory and experiment  

NASA Astrophysics Data System (ADS)

Experimental and theoretical uncertainties in the measurement of cloud condensation nuclei (CCN) with a continuous-flow thermal-gradient CCN counter from Droplet Measurement Technologies (DMT-CCNC) have been assessed by model calculations and calibration experiments with ammonium sulfate and sodium chloride aerosol particles in the diameter range of 20-220 nm. Experiments have been performed in the laboratory and during field measurement campaigns, extending over a period of more than one year and covering a wide range of operating conditions (650-1020 hPa ambient pressure, 0.5-1.0 L min-1 aerosol flow rate, 20-30°C inlet temperature, 4-34 K m-1 temperature gradient). For each set of conditions, the effective water vapor supersaturation (Seff) in the CCNC was determined from the measured CCN activation spectra and Köhler model calculations. High measurement precision was achieved under stable laboratory conditions, where relative variations of Seff in the CCNC were generally less than ±2%. During field measurements, however, the relative variability increased up to ±5-7%, which can be mostly attributed to variations of the CCNC column top temperature with ambient temperature. To assess the accuracy of the Köhler models used to calculate Seff, we have performed a comprehensive comparison and uncertainty analysis of the various Köhler models and thermodynamic parameterizations commonly used in CCN studies. For the relevant supersaturation range (0.05-2%), the relative deviations between different modeling approaches were as high as 25% for (NH4)2SO4 and 16% for NaCl. The deviations were mostly caused by the different parameterizations for the activity of water in aqueous solutions of (NH4)2SO4 and NaCl (activity parameterization, osmotic coefficient, and van't Hoff factor models). The uncertainties related to the model parameterizations of water activity clearly exceeded the CCNC measurement precision. Relative deviations caused by different ways of calculating or approximating solution density and surface tension did not exceed 3% for (NH4)2SO4 and 1.5% for NaCl. Nevertheless, they did exceed the CCNC measurement precision under well-defined operating conditions and should not be neglected in studies aimed at high accuracy. To ensure comparability of results, we suggest that CCN studies should always report exactly which Köhler model equations and parameterizations of solution properties were used. Substantial differences between the CCNC calibration results obtained with (NH4)2SO4 and NaCl aerosols under equal experimental conditions (relative deviations of Seff up to ~10%) indicate inconsistencies between widely used activity parameterizations derived from electrodynamic balance (EDB) single particle experiments (Tang and Munkelwitz, 1994; Tang, 1996) and hygroscopicity tandem differential mobility analyzer (HTDMA) aerosol experiments (Kreidenweis et al., 2005). Therefore, we see a need for further evaluation and experimental confirmation of preferred data sets and parameterizations for the activity of water in dilute aqueous (NH4)2SO4 and NaCl solutions. The experimental results were also used to test the CCNC flow model of Lance et al.~(2006), which describes the dependence of Seff on temperature, pressure, and flow rate in the CCN counter. This model could be applied after subtraction of a near-constant temperature offset and derivation of an instrument-specific thermal resistance parameter (RT?1.8 K W-1). At Seff>0.1% the relative deviations between the flow model and experimental results were mostly less than 5%, when the same Köhler model approach was used. At Seff?.1%, however, the deviations exceeded 20%, which can be attributed to non-idealities which also caused the near-constant temperature offset. Therefore, we suggest that the CCNC flow model can be used to extrapolate calibration results, but should generally be complemented by calibration experiments performed under the relevant operating conditions - during field campaigns as well as in laboratory studies.

Rose, D.; Frank, G. P.; Dusek, U.; Gunthe, S. S.; Andreae, M. O.; Pöschl, U.

2007-06-01

299

Potassium Chloride  

Center for Drug Evaluation (CDER)

Text Version... Contains Nonbinding Recommendations Draft Guidance on Potassium Chloride ... Active ingredient: Potassium Chloride ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

300

Simulated annealing and density functional theory calculations of structural and energetic properties of the ammonium chloride clusters (NH4Cl)n, (NH4+)(NH4Cl)n, and (Cl-)(NH4Cl)n, n = 1-13.  

PubMed

Simulated annealing Monte Carlo conformer searches using the "mag-walking" algorithm are employed to locate the global minima of molecular clusters of ammonium chloride of the types (NH(4)Cl)(n), (NH(4)(+))(NH(4)Cl)(n), and (Cl(-))(NH(4)Cl)(n) with n = 1-13. The M06-2X density functional theory method is used to refine and predict the structures, energies, and thermodynamic properties of the neutral, cation, and anion clusters. For selected small clusters, the resulting structures are compared to those obtained from a variety of models and basis sets, including RI-MP2 and B3LYP calculations. M06-2X calculations predict enhanced stability of the (NH(4)(+))(NH(4)Cl)(n) clusters when n = 3, 6, 8, and 13. This prediction corresponds favorably to anomalies previously observed in thermospray mass spectroscopy experiments. The (NH(4)Cl)(n) clusters show alternations in stability between even and odd values of n. Clusters of the type (Cl(-))(NH(4)Cl)(n) display a magic number distribution different from that of the cation clusters, with enhanced stability predicted for n = 2, 6, and 11. None of the observed cluster structures resemble the room-temperature CsCl structure of NH(4)Cl(s), which is consistent with previous work. Numerous clusters have structures reminiscent of the higher-temperature, rock-salt phase of the solid ammonium halides. PMID:21851071

Topper, Robert Q; Feldmann, William V; Markus, Isaac M; Bergin, Denise; Sweeney, Paul R

2011-08-31

301

DWPF ammonium ion analysis  

SciTech Connect

Ammonium nitrate production during the operation of the Defense Waste Processing Facility (DWPF) has been identified as a major problem. The accumulation of ammonium nitrate deposits in the vent system of the chemical processing cell has substantial safety implications and will require analysis of ammonium ions within DWPF process samples. As a part of the research and development of the DWPF at TNX, an ammonium analysis method developed by Dionex Corporation has been identified and confirmed to provide the required information. This memorandum describes the technical basis of the method, the accuracy and precision of the method, known interferences, and maintenance details.

Eibling, R.E.

1992-06-05

302

DEMONSTRATION OF TWO STABLE POTENTIAL STATES IN THE SQUID GIANT AXON UNDER TETRAETHYLAMMONIUM CHLORIDE  

Microsoft Academic Search

During the course of experiments designed to investigate the effects of various chemicals injected into squid giant axons (2), it was found that quater- nary ammonium ions are capable of prolonging the duration of the action potential without affecting the properties of the resting membrane appreciably. A similar effect of quaternary ammonium ions upon the action potential of other excitable

ICHIJI TASAKI; SUSUMU HAGIWARA

1957-01-01

303

Quaternary dichotomous voting rules  

Microsoft Academic Search

In this article, we provide a general model of “quaternary” dichotomous voting rules (QVRs), namely, voting rules for making\\u000a collective dichotomous decisions (to accept or reject a proposal), based on vote profiles in which four options are available\\u000a to each voter: voting (“yes”, “no”, or “abstaining”) or staying home and not turning out. The model covers most of actual\\u000a real-world

Annick Laruelle; Federico Valenciano

2010-01-01

304

Aluminum chloride restoration of in situ leached uranium ores  

SciTech Connect

During in situ uranium mining using ammonium bicarbonate lixiviant, the ammonium exchanges with cations on the ore's clay. After mining is complete, the ammonium may desorb into post-leach ground water. For the particular ore studied, other chemicals (i.e., uranium and selenium) which are mobilized during the leach process, have also been found in the post-leach ground water. Laboratory column tests, used to simulate the leaching process, have shown that aluminum chloride can rapidly remove ammonium from the ore and thus greatly reduce the subsequent ammonium leakage level into ground water. The aluminum chloride has also been found to reduce the leakage levels of uranium and selenium. In addition, the aluminum chloride treatment produces a rapid improvement in permeability.

Grant, D.C.; Burgman, M.A.

1982-09-01

305

Micellization and related behavior of binary and ternary surfactant mixtures in aqueous medium: cetyl pyridinium chloride (CPC), cetyl trimethyl ammonium bromide (CTAB), and polyoxyethylene (10) cetyl ether (Brij-56) derived system.  

PubMed

Mixed micelles formed with cetyl pyridinium chloride (CPC), cetyl trimethylammonium bromide (CTAB), and polyoxyethylene (10) cetyl ether (Brij-56) mixed in different combinations in aqueous medium have been studied in detail by tensiometric, conductometric, calorimetric, spectrophotometric, and fluorimetric techniques. Different physicochemical properties such as critical micellar concentration (cmc), micellar dissociation, energetic parameters (free energy, enthalpy, and entropy) of micellization, interfacial adsorption, and micellar aggregation number have been determined. The results have been analyzed in terms of the equations of Clint, Motomura, Rosen, Rubingh, Blankschtein et al., and Rubingh and Holland for justification of the experimental cmc, determination of micellar composition parameters, quantification of interaction among the mixed micelle components, and estimation of their activity coefficients. PMID:16852875

Chakraborty, Tanushree; Ghosh, Soumen; Moulik, Satya P

2005-08-11

306

Futile cycling of ammonium ions via the high affinity potassium uptake system (Kdp) of Escherichia coli  

Microsoft Academic Search

Escherichia coli Frag1 was grown under various nutrient limitations in chemostat culture at a fixed temperature, dilution rate and pH both in the presence and the absence of a high concentration of ammonium ions by using either ammonium chloride or dl-alanine as the sole nitrogen source. The presence of high concentrations of ammonium ions in the extracellular fluids of potassium-limited

Ed T. Buurman; M. Joost Teixeira de Mattos; Oense M. Neijssel

1991-01-01

307

Selective ion electrode measurements of chloride concentrations in the determination of cation exchange capacities of soils  

Microsoft Academic Search

The determination of chloride ion in soil extracts for cation exchange capacity in the presence of ammonium ions of nearly equal concentration (5 x 10 M) and excess sodium sulphate (0.5 M) by an Orion solid state selective ion electrode is reported. Ammonium ions were found to interfere by reducing the determined value of the chloride ion by up to

R. St. C. Smart; A. D. Thomas; D. P. Drover

1974-01-01

308

Ammonium nitrate explosive systems  

DOEpatents

Novel explosives which comprise mixtures of ammonium nitrate and an ammonium salt of a nitroazole in desired ratios are disclosed. A preferred nitroazole is 3,5-dinitro-1,2,4-triazole. The explosive and physical properties of these explosives may readily be varied by the addition of other explosives and oxidizers. Certain of these mixtures have been found to act as ideal explosives.

Stinecipher, Mary M. (Los Alamos, NM); Coburn, Michael D. (Los Alamos, NM)

1981-01-01

309

The anaerobic oxidation of ammonium  

Microsoft Academic Search

From recent research it has become clear that at least two different possibilities for anaerobic ammonium oxidation exist in nature. `Aerobic' ammonium oxidizers like Nitrosomonas eutropha were observed to reduce nitrite or nitrogen dioxide with hydroxylamine or ammonium as electron donor under anoxic conditions. The maximum rate for anaerobic ammonium oxidation was about 2 nmol NH+4 min?1 (mg protein)?1 using

Mike S. M Jetten; Marc Strous; Katinka T van de Pas-Schoonen; Jos Schalk; Udo G. J. M van Dongen; Astrid A van de Graaf; Susanne Logemann; Gerard Muyzer; Mark C. M van Loosdrecht; J. Gijs Kuenen

1998-01-01

310

Process-induced phase transformation of berberine chloride hydrates.  

PubMed

Berberine is a natural quaternary ammonium alkaloid used clinically in the chloride salt form for the treatment of diarrhea in many Asian countries. Although the hydrate formation of berberine chloride (BCl) is well documented, the associated mechanism and implications in pharmaceutical formulation have not been studied in detail. In this study, pure BCl dihydrate and BCl tetrahydrate were recrystallized from water and their phase transformation behaviors under defined conditions were investigated. Additionally, pharmacopoeial grade BCl material consisting predominantly of the dihydrate form was examined for potential phase changes when being subjected to a conventional wet granulation procedure for tablet production. Results from solubility measurements, thermal analysis, variable temperature-powder X-ray diffraction (VT-PXRD), and variable temperature-Fourier transform infrared spectroscopy (VT-FTIR) confirmed the solid-state interconversions between the tetrahydrate and dihydrate at 30-49 degrees C and between the dihydrate and anhydrate at 70-87 degrees C. Consistent with the observed phase changes of the two pure hydrates, wet massing of the pharmacopoeial grade BCl sample led to a thermodynamics-driven transition to the tetrahydrate form at room temperature while subsequent tray drying at 50 degrees C caused a reversion back to the dihydrate form. The rate and extent of such hydrate conversion depended largely on the water activity of the granulated powder matrix, which in turn was governed by the particular excipients employed. The present findings have important implications in the regulation of the hydrate forms of BCl in the finished products using specific excipients. PMID:19894277

Tong, Henry H Y; Chow, Aviva S F; Chan, H M; Chow, Albert H L; Wan, Yetta K Y; Williams, Ian D; Shek, Fanny L Y; Chan, Chak K

2010-04-01

311

Ammonium secretion by Malpighian tubules of Drosophila melanogaster: application of a novel ammonium-selective microelectrode.  

PubMed

Ammonia is a toxic nitrogenous waste product of amino acid metabolism that may accumulate to high levels in the medium ingested by larvae of the fruit fly Drosophila melanogaster. Here we report measurements of haemolymph NH4(+) concentration and the secretion of NH4(+) by the Malpighian (renal) tubules. Measurement of NH4(+) concentrations in secreted droplets is complicated either by the requirement for large sample volumes for enzymatic assays or by the inadequate selectivity of NH4(+)-selective microelectrodes based on nonactin. We have developed a novel liquid membrane NH4(+)-selective microelectrode based on a 19-membered crown compound (TD19C6), which has been used previously in ammonium-selective macroelectrodes. In conjunction with an improved technique for correcting for interference of potassium, NH4(+)-selective microelectrodes based on TD19C6 permit accurate measurement of ammonium concentration in haemolymph samples and nanolitre droplets of fluid secreted by the Malpighian tubules of D. melanogaster. The results indicate that active secretion of ammonium into the Malpighian tubule lumen is sufficient to maintain concentrations of ~1 mmol l(-1) ammonium in the haemolymph of larvae reared on diets containing 100 mmol l(-1) ammonium chloride. PMID:23821719

Browne, Austin; O'Donnell, Michael J

2013-07-02

312

[Characterization of cross-linked quaternary chitosan salt and its adsorption of perchlorate from water].  

PubMed

Cross-linked quaternary chitosan salt was prepared and used to adsorb perchlorate from water. Parameters of cross-linking agent, temperature and pH were investigated to optimize the reaction conditions. The adsorption and regeneration ability of the adsorbent were also conducted. Quaternary chitosan salt could be fixed by cross-linking with glutaraldehyde using ethanol as dispersant. The optimal glutaraldehyde dosage and temperature were 6.82% and 45 degrees C, respectively. The cross-linked reaction was independent of pH with the range from 3 to 12. Quaternary chitosan salt was cross-linked mainly through the reaction between the methyl groups of ammonium on quaternary chitosan salt and the -C=O groups on glutaraldehyde. The optimal pH(zpc) of the adsorbent was about 10.6. The adsorbent showed high efficiency for perchlorate removal, and the adsorption capacity varied from 12.321 mg/g to 117.819 mg/g with the ClO4(-) concentration range from 5 mg/L to 200 mg/L. The spent adsorbents could be effectively regenerated by NaCl brine with the concentration more than 0.3%. The results suggest that the cross-linked chitosan quaternary ammonium salt would be a promising method for perchlorate removal from water. PMID:22165217

Xie, Yan-Hua; Li, Shi-Yu; Liu, Guang-Li

2011-09-01

313

Influence of ammonium salt on electrowinning of copper from ammoniacal alkaline solutions  

Microsoft Academic Search

In order to develop an energy-saving copper recycling process from wastes, electrochemical measurements were conducted in ammoniacal alkaline solutions containing Cu(I) ions and an ammonium salt of sulfate, chloride or nitrate. The results of each system were then compared. The polarization measurements suggested that the voltage required for the electrode process is lower in the chloride and nitrate systems than

Tetsuo Oishi; Kazuya Koyama; Hirokazu Konishi; Mikiya Tanaka; Jae-Chun Lee

2007-01-01

314

Inhibition of growth and photosynthesis of selected green microalgae as tools to evaluate toxicity of dodecylethyldimethyl-ammonium bromide  

Microsoft Academic Search

The effect of dodecylethyldimethyl-ammonium bromide (DEAB), a quaternary ammonium, compound widely used as disinfectant, on\\u000a phytoplankton of inland water systems was analysed by using an experimental model. A toxicity test was based on inhibition\\u000a of photosynthesis performances (effective quantum yield from photosystem II, ?PSII and O2 production) of the phytoplanktonic species Scenedesmus\\u000a intermedius and Dictiosphaerium chlorelloides (Chlorophyceae) under growing doses

S. Sánchez-Fortún; F. Marvá; A. D’ors; E. Costas

2008-01-01

315

Effects of Ammonium Sulfate and Ammonium Phosphate on Flammability.  

National Technical Information Service (NTIS)

Ponderosa pine needle and aspen excelsior fuel beds were treated with various amounts of ammonium sulfate and ammonium phosphate and burned in a wind tunnel under controlled environmental conditions. The rate of fire spread, rate of weight loss (equivalen...

C. W. George A. D. Blakely

1972-01-01

316

70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM NITRATE IN STORAGE. APRIL 18, 1919. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

317

Synthesis of some new bisquaternary ammonium salts as acid corrosion inhibitors for carbon steel  

Microsoft Academic Search

A variety of bisquaternary ammonium salts was prepared for the first time by reacting N,N,N?,N?-tetraallyl-1,6-hexanediamine with allyl chloride, propargyl chloride, benzyl chloride, and 1-bromododecane in excellent yields (>90 per cent). Inhibition efficiency for different concentrations of the synthesised compounds for the inhibition of corrosion of carbon steel in 1 M HCl exposed for 6 h at 60°C was determined gravimetrically.

M. Tariq Saeed; Sk. Asrof Ali

2003-01-01

318

[Quaternary prevention in the elderly].  

PubMed

Quaternary prevention is a group of measures taken to prevent, decrease and/or alleviate the harm caused by health activities. Health activities not only generally produce benefits, but also harm. That is to say, although medical intervention is mainly favourable, there is a dynamic balance that requires continuous assessment of the clinical situation as naturally only those health activities that achieve more benefit than harm at the end are justified. Quaternary prevention is the avoidance of unnecessary medical activity, such as "check-ups". In another example, quaternary prevention is the recommendation of preventive measures of proven efficacy. As regards diagnosis, quaternary prevention is, for example, the avoidance of screening without foundation, such as in prostate cancer. The appropriate use of antibiotics in upper respiratory tract infections serves as an example of quaternary prevention in the field of treatment. Another example is the application of the correct rehabilitation techniques in non-specific low back pain, such as swimming and maintaining an active life as much as possible. Not to forget other important "non-classic" aspects in the elderly, such as to limit the harm that can be caused by physical movement restriction devices. These and other examples in daily practice are considered in this article to encourage the continual assessment of quaternary prevention, the classic primum non nocere "first, do no harm". PMID:23062686

Gérvas, Juan

2012-10-11

319

Chloride Test  

MedlinePLUS

... Chloride Related tests: Sodium , Potassium , Bicarbonate (total CO2) , Electrolytes , CMP , BMP , Blood Gases At a Glance Test ... if there is a problem with your body's electrolyte balance or acid-base balance and to monitor ...

320

Trospium chloride: A quaternary amine with unique pharmacologic properties  

Microsoft Academic Search

The mainstay of pharmacologic treatment of overactive bladder is anticholinergic therapy. Cholinergic blockade is efficacious\\u000a in decreasing the symptoms of urgency, frequency, and urge incontinence, but also is associated with undesirable side effects\\u000a such as dry mouth, blurred vision, constipation, and central nervous system side effects. The property of anticholinergic\\u000a agents that has been associated with increased efficacy and tolerability

Raymond W. Pak; Steven P. Petrou; David R. Staskin

2003-01-01

321

Ammonium Handling by Superficial and Juxtamedullary Nephrons in the Rat  

PubMed Central

Papillary and surface micropuncture was used to assess the effects of a chronic metabolic acidosis on the renal tubular handling of ammonium by surface nephrons, juxtamedullary nephrons, and the terminal segment of collecting duct. Rats chronically fed ammonium chloride had an expected decline in arterial pH and bicarbonate concentration associated with a doubling in the amount of ammonium excreted and a decline in urine pH. The glomerular filtration rate and absolute delivery of water and sodium to micropuncture sites of surface and deep nephrons was not measurably altered. Ammonium delivery to the end of the proximal tubule increased from 853±102% to 1,197±142% (SE) of the filtered load of ammonium after the induction of metabolic acidosis. This increase was due to a rise in tubular fluid ammonium content from 2.31±0.23 to 4.06±0.28 mM/liter. After the induction of acidosis, absolute and fractional delivery of ammonium ion to the end of the distal tubule was less than to the end of the accessible portion of the proximal tubule. These findings indicate that ammonium is lost in the intervening segment. Ammonium handling by deep nephrons was profoundly affected by acid loading. Absolute delivery to the bend of the loop of Henle increased twofold while fractional delivery rose from 1,222±108% to 1,780±132% of the filtered ammonium. This was due to a marked increase in ammonia entry. During acidosis, ammonium delivery to the terminal segment of the collecting duct was doubled (709±137% in controls vs. 1,415±150% in acidosis, P < 0.005) but did not change between proximal and tip collecting duct sites. In both groups of animals delivery of ammonium to the terminal segment of the collecting duct was greater than to end distal tubular micropuncture sites suggesting that ammonia entry occurred between these two sites. The differences in delivery was greater after the induction of a metabolic acidosis (887±140% vs. 384±144%, P < 0.05). Thus, the present study indicates that deep nephrons contribute to the adaptive increase in ammonium excretion seen during the induction of metabolic acidosis. The data also suggest that ammonia leaves the nephrons at a site(s) along the loop of Henle to enter the collecting duct and that the induction of a metabolic acidosis enhances this reentry.

Buerkert, John; Martin, Daniel; Trigg, David

1982-01-01

322

Effect of Intra-articular 4-(S)-amino-5-(4-{4-[2,4-dichloro-3-(2,4-dimethyl-8-quinolyloxymethyl)phenylsulfonamido]-tetrahydro-2H-4-pyranylcarbonyl} piperazino)-5-oxopentyl](trimethyl)ammonium chloride hydrochloride (MEN16132), a kinin B2 receptor antagonist, on nociceptive response in monosodium iodoacetate-induced experimental osteoarthritis in rats.  

PubMed

The present study was designed to investigate the role of bradykinin (BK) in the knee joint osteoarthritis induced by intra-articular (i.ar.) administration of monosodium iodoacetate (MIA) in the rat, and to determine the efficacy of the kinin B(2) receptor antagonists, 4-(S)-amino-5-(4-{4-[2,4-dichloro-3-(2,4-dimethyl-8-quinolyloxymethyl)phenylsulfonamido]-tetrahydro-2H-4-pyranylcarbonyl} piperazino)-5-oxopentyl](trimethyl)ammonium chloride hydrochloride (MEN16132) and icatibant, in reducing pain. Rats received MIA (1 mg/25 microl i.ar.) in the right knee. MEN16132, icatibant (1, 3, and 10 microg/25 microl i.ar.), or saline were administered 7 days after MIA treatment, and their antinociceptive effect was observed for 2 weeks. MEN16132 induced a marked and sustained reduction of incapacitation produced by MIA, approximately 56% inhibition of pain at 3 microg/knee. MEN16132 analgesia was more potent and longer lasting, up to 10 days, than icatibant. MEN16132 (3 microg/knee), at different time points from MIA treatment in separate groups of animals, produced comparable maximal antinociceptive effects, whereas the pain response induced by MIA was unaffected if MEN16132 (10 microg/knee) was administered in the contralateral knee. Indomethacin at high doses (100-625 microg/knee) inhibited by approximately 40% but with a short duration the MIA-induced pain. MIA treatment produced a significant increase of BK and prostaglandin E(2) (PGE(2)) metabolite levels in synovial fluid up to 21 days, and PGE(2) metabolite levels were reduced almost to basal values by MEN16132. In conclusion the potent and long-lasting analgesic effect of MEN16132 in MIA-induced osteoarthritis indicates an important role for BK in osteoarthritic pain, and suggests that MEN16132 can be a candidate for the treatment of this chronic disease. PMID:19745108

Cialdai, Cecilia; Giuliani, Sandro; Valenti, Claudio; Tramontana, Manuela; Maggi, Carlo Alberto

2009-09-10

323

Poly-N-Acetylglucosamine Matrix Polysaccharide Impedes Fluid Convection and Transport of the Cationic Surfactant Cetylpyridinium Chloride through Bacterial Biofilms?  

PubMed Central

Biofilms are composed of bacterial cells encased in a self-synthesized, extracellular polymeric matrix. Poly-?(1,6)-N-acetyl-d-glucosamine (PNAG) is a major biofilm matrix component in phylogenetically diverse bacteria. In this study we investigated the physical and chemical properties of the PNAG matrix in biofilms produced in vitro by the gram-negative porcine respiratory pathogen Actinobacillus pleuropneumoniae and the gram-positive device-associated pathogen Staphylococcus epidermidis. The effect of PNAG on bulk fluid flow was determined by measuring the rate of fluid convection through biofilms cultured in centrifugal filter devices. The rate of fluid convection was significantly higher in biofilms cultured in the presence of the PNAG-degrading enzyme dispersin B than in biofilms cultured without the enzyme, indicating that PNAG decreases bulk fluid flow. PNAG also blocked transport of the quaternary ammonium compound cetylpyridinium chloride (CPC) through the biofilms. Binding of CPC to biofilms further impeded fluid convection and blocked transport of the azo dye Allura red. Bioactive CPC was efficiently eluted from biofilms by treatment with 1 M sodium chloride. Taken together, these findings suggest that CPC reacts directly with the PNAG matrix and alters its physical and chemical properties. Our results indicate that PNAG plays an important role in controlling the physiological state of biofilms and may contribute to additional biofilm-associated processes such as biocide resistance.

Ganeshnarayan, Krishnaraj; Shah, Suhagi M.; Libera, Matthew R.; Santostefano, Anthony; Kaplan, Jeffrey B.

2009-01-01

324

Poly-N-acetylglucosamine matrix polysaccharide impedes fluid convection and transport of the cationic surfactant cetylpyridinium chloride through bacterial biofilms.  

PubMed

Biofilms are composed of bacterial cells encased in a self-synthesized, extracellular polymeric matrix. Poly-beta(1,6)-N-acetyl-d-glucosamine (PNAG) is a major biofilm matrix component in phylogenetically diverse bacteria. In this study we investigated the physical and chemical properties of the PNAG matrix in biofilms produced in vitro by the gram-negative porcine respiratory pathogen Actinobacillus pleuropneumoniae and the gram-positive device-associated pathogen Staphylococcus epidermidis. The effect of PNAG on bulk fluid flow was determined by measuring the rate of fluid convection through biofilms cultured in centrifugal filter devices. The rate of fluid convection was significantly higher in biofilms cultured in the presence of the PNAG-degrading enzyme dispersin B than in biofilms cultured without the enzyme, indicating that PNAG decreases bulk fluid flow. PNAG also blocked transport of the quaternary ammonium compound cetylpyridinium chloride (CPC) through the biofilms. Binding of CPC to biofilms further impeded fluid convection and blocked transport of the azo dye Allura red. Bioactive CPC was efficiently eluted from biofilms by treatment with 1 M sodium chloride. Taken together, these findings suggest that CPC reacts directly with the PNAG matrix and alters its physical and chemical properties. Our results indicate that PNAG plays an important role in controlling the physiological state of biofilms and may contribute to additional biofilm-associated processes such as biocide resistance. PMID:19114520

Ganeshnarayan, Krishnaraj; Shah, Suhagi M; Libera, Matthew R; Santostefano, Anthony; Kaplan, Jeffrey B

2008-12-29

325

Synthesis and Characterization of Polyurethane with Pendant Fluorinated Bis-Ammonium Salts Attached on the Hard Segment  

Microsoft Academic Search

Polyurethanes with pedant quaternary ammonium salts (QAS) have been shown potent antimicrobial properties against gram-positive bacteria but less sensitive to gram-negative ones. Besides, due to using a large amount of QAS chain extenders, Polyurethanes with pedant QAS have been proven to be high water adsorption and even water soluble. In order to solve the two problems mentioned above, Novel polyurethanes

Jianbin Luo

2009-01-01

326

Electrochemically stable fluorohydrogenate ionic liquids based on quaternary phosphonium cations  

Microsoft Academic Search

Fluorohydrogenate ionic liquids of quaternary phosphonium cations, tri-n-butylmethylphosphonium (P4441) fluorohydrogenate, tetra-n-butylphosphonium (P4444) fluorohydrogenate, and tri-n-butyl-n-octylphosphonium (P4448) fluorohydrogenate, have been synthesized by the metatheses of anhydrous hydrogen fluoride and the corresponding phosphonium chloride precursors. All the obtained salts have melting points below room-temperature with a vacuum-stable composition of P444m(FH)2.3F (m=1, 4, and 8) and were characterized by density, conductivity, and viscosity

Shunsuke Kanematsu; Kazuhiko Matsumoto; Rika Hagiwara

2009-01-01

327

Chloride channelopathies.  

PubMed

Channelopathies, defined as diseases that are caused by mutations in genes encoding ion channels, are associated with a wide variety of symptoms. Impaired chloride transport can cause diseases as diverse as cystic fibrosis, myotonia, epilepsy, hyperekplexia, lysosomal storage disease, deafness, renal salt loss, kidney stones and osteopetrosis. These disorders are caused by mutations in genes belonging to non-related gene families, i.e. CLC chloride channels and transporters, ABC transporters, and GABA- and glycine receptors. Diseases due to mutations in TMEM16E and bestrophin 1 might be due to a loss of Ca++-activated Cl- channels, although this remains to be shown. PMID:19708126

Planells-Cases, Rosa; Jentsch, Thomas J

2009-03-01

328

Sidebranching in the Dendritic Crystal Growth of Ammonium Chloride  

NASA Astrophysics Data System (ADS)

We report measurements of the dendritic crystal growth of NH4Cl from supersaturated aqueous solution at small supersaturations. Sidebranch growth in this regime is challenging to model well, and the origin of the sidebranches is not fully understood. The early detection of sidebranches requires measurements of small deviations from the smooth steady state shape, but that shape is not well known at the intermediate distances relevant for sidebranch measurements. One model is that sidebranches result from the selective amplification of microscopic noise. We compare measurements of the sidebranch envelope with predictions of the noise-induced sidebranching model of Gonz'alez-Cinca, Ram'irez-Piscina, Casademunt, and Hern'andez-Machado [Phys Rev. E, 63, 051602 (2001)]. We find that the measured amplitude is somewhat larger than predicted, and the shape of the sidebranch envelope is also different. A second model is that sidebranches result from small oscillations of the tip. We have observed no such oscillations, but very small ones can not be ruled out. No measurement of the tip region can be completely free of contamination from early sidebranches, so it can be challenging to distinguish between an oscillating tip and a smooth tip with sidebranches starting nearby.

Dougherty, Andrew

2012-02-01

329

Sidebranching in the Dendritic Crystal Growth of Ammonium Chloride  

NASA Astrophysics Data System (ADS)

We report new measurements of the dendritic crystal growth of NH4Cl from supersaturated aqueous solution. We report the first measurement of the capillary length d0 to be approximately 2 x10-4 ?m. For growth at small dimensionless supersaturations ? on the order of 0.005, we have estimated the stability constant &*circ; to be approximately 0.008. The origin of the sidebranches in dendritic growth is not fully understood, but one model is that they result from the selective amplification of microscopic noise. We will compare measurements of the sidebranch envelope with predictions of the noise-induced sidebranching model of Gonz'alez-Cinca, Ram'irez-Piscina, Casademunt, and Hern'andez-Machado [Phys Rev. E, 63, 051602 (2001)]. A second model is that sidebranches result from small oscillations of the tip. We have observed no such oscillations, but very small ones can not be ruled out. Given the finite experimental resolution, no measurement of the tip region can be completely free of contamination from early sidebranches. We will discuss this and other experimental challenges that need to be overcome before we can understand the origin of sidebranches.

Dougherty, Andrew; Stinner, Franklin

2010-03-01

330

The shape of ammonium chloride dendrite tips at small supersaturation  

NASA Astrophysics Data System (ADS)

We report detailed measurements of the tip shapes of three-dimensional NH_4Cl dendrites grown from aqueous solution at small supersaturation.[1] We compare three different models for determining the tip position and shape: parabolic, parabolic with a fourth-order correction, and power law[2]. We also consider an intensity centroid method[3] useful for locating tip positions even when the tip is too small to image accurately. None of these methods is ideal, but the fourth-order fit appears to provide the most robust description of both the tip shape and position for the crystals grown in this work. Since all models considered include data a finite distance back from the tip, the question of whether incipient sidebranches contaminate the computed tip position and shape will be considered when looking for possible tip oscillations. 1. More details and references are available at http://www.lafayette.edu/%7Edoughera/talks/aps2003/index.html 2. U. Bisang and J. H. Bilgram, Phys. Rev. E 54, 5309 (1996). 3. J. C. LaCombe et al., Phys. Rev. E 65, 031604 (2002).

Dougherty, Andrew; Lahiri, Mayank

2003-03-01

331

Experimental study of directional solidification of aqueous ammonium chloride solution  

Microsoft Academic Search

Directional solidification experiments have been carried out using the analog casting system of NH4Cl-H2O solution by cooling it from below with a constant-temperature surface ranging from -31.5 C to +11.9 C. The NH4Cl concentration was 26 percent in all solutions, with a liquidus temperature of 15 C. It was found that finger convection occurred in the fluid region just above

C. F. Chen; Falin Chen

1991-01-01

332

Steady-state solidification of aqueous ammonium chloride  

NASA Astrophysics Data System (ADS)

We report on a series of experiments in which a Hele-Shaw cell containing aqueous solutions of NH4Cl was translated at prescribed rates through a steady temperature gradient. The salt formed the primary solid phase of a mushy layer as the solution solidified, with the salt-depleted residual fluid driving buoyancy-driven convection and the development of chimneys in the mushy layer. Depending on the operating conditions, several morphological transitions occurred. A regime diagram is presented quantifying these transitions as a function of freezing rate and the initial concentration of the solution. In general, for a given concentration, increasing the freezing rate caused the steady-state system to change from a convecting mushy layer with chimneys to a non-convecting mushy layer below a relatively quiescent liquid, and then to a much thinner mushy layer separated from the liquid by a region of active secondary nucleation. At higher initial concentrations the second of these states did not occur. At lower concentrations, but still above the eutectic, the mushy layer disappeared. A simple mathematical model of the system is developed which compares well with the experimental measurements of the intermediate, non-convecting state and serves as a benchmark against which to understand some of the effects of convection. Movies are available with the online version of the paper.

Peppin, S. S. L.; Huppert, Herbert E.; Worster, M. Grae

333

Heterogeneous reactions of alkylamines with ammonium sulfate and ammonium bisulfate.  

PubMed

The heterogeneous reactions between alkylamines and ammonium salts (ammonium sulfate and ammonium bisulfate) have been studied using a low-pressure fast flow reactor coupled to an ion drift-chemical ionization mass spectrometer (ID-CIMS) at 293 ± 2 K. The uptake of three alkylamines, i.e., monomethylamine, dimethylamine, and trimethylamine, on ammonium sulfate shows a displacement reaction of ammonium by aminium, evidenced by the release of ammonia monitored using protonated acetone dimer as the reagent ion. For the three alkylamines, the initial uptake coefficients (?(0)) range from 2.6 × 10(-2) to 3.4 × 10(-2) and the steady-state uptake coefficients (?(ss)) range from 6.0 × 10(-3) to 2.3 × 10(-4) and decrease as the number of methyl groups on the alkylamine increases. A different reaction mechanism is observed for the uptake of the three alkylamines on ammonium bisulfate, which is featured by an acid-base reaction (neutralization) with irreversible alkylamine loss and no ammonia generation and occurs at a rate limited by diffusion of gaseous alkylamines to the ammonium bisulfate surface. Our results reveal that the reactions between alkylamines and ammonium salts contribute to particle growth and alter the composition of ammonium sulfate and bisulfate aerosols in the atmosphere. PMID:21539370

Qiu, Chong; Wang, Lin; Lal, Vinita; Khalizov, Alexei F; Zhang, Renyi

2011-05-03

334

Inhibition of growth and photosynthesis of selected green microalgae as tools to evaluate toxicity of dodecylethyldimethyl-ammonium bromide.  

PubMed

The effect of dodecylethyldimethyl-ammonium bromide (DEAB), a quaternary ammonium, compound widely used as disinfectant, on phytoplankton of inland water systems was analysed by using an experimental model. A toxicity test was based on inhibition of photosynthesis performances (effective quantum yield from photosystem II, Phi(PSII) and O(2) production) of the phytoplanktonic species Scenedesmus intermedius and Dictiosphaerium chlorelloides (Chlorophyceae) under growing doses of DEAB. A concentration-dependent toxic response was obtained in both parameters analysed. In addition, this response was almost immediate. Consequently, the measurement of both parameters (Phi(PSII )and O(2) production) allows to assess DEAB toxicity with higher standards of precision and repeatability. We propose that this procedure could be used to detect presence of quaternary ammonium pollutants in freshwater. PMID:18188698

Sánchez-Fortún, S; Marvá, F; D'ors, A; Costas, E

2008-01-11

335

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...  

Code of Federal Regulations, 2010 CFR

...ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo...contamination such as flammable liquids, combustible liquids,...

2010-07-01

336

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...  

Code of Federal Regulations, 2010 CFR

...ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo...contamination such as flammable liquids, combustible liquids,...

2009-07-01

337

Biological effectiveness of didecyl dimethyl ammonium tetrafluoroborate (DBF) against basidiomycetes following preconditioning in soil bed tests  

Microsoft Academic Search

Evaluation of wood preservatives in soil-contact tests is becoming an important issue since detoxification of wood-protecting\\u000a compounds by fungi and bacteria found in soil may decrease the resistance of treated wood. In this study, the decay resistance\\u000a of wood treated with didecyl dimethyl ammonium tetrafluoroborate (DBF), a recently developed quaternary ammonia compound,\\u000a was evaluated in both soil bed and laboratory

S. Nami Kartal; Christian Brischke; Andreas O. Rapp; Yuji Imamura

2006-01-01

338

Polyclonal antibodies mediated immobilization of a peroxidase from ammonium sulphate fractionated bitter gourd ( Momordica charantia) proteins  

Microsoft Academic Search

Polyclonal antibody bound Sepharose 4B support has been exploited for the immobilization of bitter gourd peroxidase directly from ammonium sulphate precipitated proteins. Immunoaffinity immobilized bitter gourd peroxidase exhibited high yield of immobilization. IgG-Sepharose 4B bound bitter gourd peroxidase showed a higher stability against heat, chaotropic agents (urea and guanidinium chloride), detergents (cetyl trimethyl ammonium bromide and Surf Excel), proteolytic enzyme

Aiman Fatima; Qayyum Husain

2007-01-01

339

Quaternary uplift of southern Italy  

Microsoft Academic Search

Dramatic coastline changes demonstrate rapid Quaternary uplift of Calabria in southern Italy. Because most of the west (Tyrrhenian Sea) coast is normal fault bounded, previous work has asserted that its uplift is local footwall uplift related to extension. However, the east (Ionian Sea) coast is also uplifting but is not normal fault bounded. This reanalysis, based on original field work

Rob Westaway

1993-01-01

340

Quaternary Studies: An Interdisciplinary Program  

NSDL National Science Digital Library

Rutgers University promotes its Graduate Certificate in Quaternary Studies where students take part in geology, geography, meteorology, and other disciplines interested in the last couple of million years of Earth's history. Students and educators can find information on the researchers involved with the program and the necessary course work.

1969-12-31

341

Quaternary alkaloids of Argemone mexicana.  

PubMed

Four quaternary isoquinoline alkaloids, dehydrocorydalmine, jatrorrhizine, columbamine, and oxyberberine, have been isolated from the whole plant of Argemone mexicana Linn. (Papaveraceae) and their structures established by spectral evidence. This is the first report of these alkaloids (dehydrocorydalmine, jatrorrhizine, columbamine, and oxyberberine) from Argemone mexicana and the Argemone genus. PMID:20645832

Singh, Sarita; Singh, Tryambak Deo; Singh, Virendra Pratap; Pandey, Vidya Bhushan

2010-02-01

342

pH responsive properties of non-fouling mixed-charge polymer brushes based on quaternary amine and carboxylic acid monomers.  

PubMed

In this work, we report a tunable mixed-charge copolymer surface containing positively charged quaternary amine monomers ([2-(acryloyloxy)ethyl] trimethyl ammonium chloride, TMA) and negatively-charged carboxylic acid monomers (2-carboxy ethyl acrylate, CAA). The non-fouling properties of this copolymer coating depend on environmental pH. The surface has charge neutrality under neutral and basic conditions, and is positively charged under acidic conditions due to the protonation of the carboxylic acid group. This transition in surface charge with respect to pH allows the surface to be switched from bacteria-adhesive to bacteria-resistant. We demonstrate that the bacteria adhered to the surface under acidic conditions can be easily released as bulk pH increases. This tunable surface can be used to collect a contaminant and then be externally stimulated to release the contaminant, to allow for analysis of its composition. Its bacteria attraction and release property makes it very promising for decontamination and biomedical applications. PMID:20045182

Mi, Luo; Bernards, Matthew T; Cheng, Gang; Yu, Qiuming; Jiang, Shaoyi

2010-01-04

343

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation...176.410 Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. (a) This...

2009-10-01

344

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation...176.410 Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. (a) This...

2010-10-01

345

Ammonium diphosphitoindate(III)  

PubMed Central

The crystal structure of the title compound, NH4[In(HPO3)2], is built up from InIII cations (site symmetry 3m.) adopting an octa­hedral environment and two different phosphite anions (each with site symmetry 3m.) exhibiting a triangular–pyramidal geometry. Each InO6 octa­hedron shares its six apices with hydrogen phosphite groups. Reciprocally, each HPO3 group shares all its O atoms with three different metal cations, leading to [In(HPO3)2]? layers which propagate in the ab plane. The ammonium cation likewise has site symmetry 3m.. In the structure, the cations are located between the [In(HPO3)2]? layers of the host framework. The sheets are held together by hydrogen bonds formed between the NH4 + cations and the O atoms of the framework.

Hamchaoui, Farida; Rebbah, Houria; Le Fur, Eric

2013-01-01

346

Polyclonal antibodies mediated immobilization of a peroxidase from ammonium sulphate fractionated bitter gourd (Momordica charantia) proteins.  

PubMed

Polyclonal antibody bound Sepharose 4B support has been exploited for the immobilization of bitter gourd peroxidase directly from ammonium sulphate precipitated proteins. Immunoaffinity immobilized bitter gourd peroxidase exhibited high yield of immobilization. IgG-Sepharose 4B bound bitter gourd peroxidase showed a higher stability against heat, chaotropic agents (urea and guanidinium chloride), detergents (cetyl trimethyl ammonium bromide and Surf Excel), proteolytic enzyme (trypsin) and water-miscible organic solvents (propanol, THF and dioxane). The activity of immobilized bitter gourd peroxidase was significantly enhanced in the presence of cetyl trimethyl ammonium bromide and after treatment with trypsin as compared to soluble enzyme. PMID:17137839

Fatima, Aiman; Husain, Qayyum

2006-10-27

347

Saline-water contamination in Quaternary deposits and the Poplar River, East Poplar Oil Field, northeastern Montana  

USGS Publications Warehouse

The extent of saline-water contamination in Quaternary deposits in and near the East Poplar oil field may be as much as 12.4 square miles and appears to be present throughout the entire saturated zone. The saline-water contamination affects 9-60 billion gallons of ground water. Saline- contaminated water moves westward through Quaternary glacial deposits and merges with southward-flowing water in Quaternary alluvium in the Poplar River valley. Saline ground water discharges into the Poplar River, and increases the dissolved-solids and chloride concentrations of the river. The probable source of saline-water contamination in the Quaternary deposits is brine that is a byproduct of the production of crude oil in the East Poplar oil field study area.

Thamke, J. N.; Craigg, S. D.

1997-01-01

348

Ammonium Regulation in Aspergillus nidulans  

PubMed Central

l-Glutamate uptake, thiourea uptake, and methylammonium uptake and the intracellular ammonium concentration were measured in wild-type and mutant cells of Aspergillus nidulans held in various concentrations of ammonium and urea. The levels of l-glutamate uptake, thiourea uptake, nitrate reductase, and hypoxanthine dehydrogenase activity are determined by the extracellular ammonium concentration. The level of methylammonium uptake is determined by the intracellular ammonium concentration. The uptake and enzyme characteristics of the ammonium-derepressed mutants, meaA8, meaB6, DER3, amrA1, xprD1, and gdhA1, are described. The gdhA mutants lack normal nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase (NADP-GDH) activity and are derepressed with respect to both external and internal ammonium. The other mutant classes are derepressed only with respect to external ammonium. The mutants meaA8, DER3, amrA1, and xprD1 have low levels of one or more of the l-glutamate, thiourea, and methylammonium uptake systems. A model for ammonium regulation in A. nidulans is put forward which suggests: (i) NADP-GDH located in the cell membrane complexes with extracellular ammonium. This first regulatory complex determines the level of l-glutamate uptake, thiourea uptake, nitrate reductase, and xanthine dehydrogenase by repression or inhibition, or both. (ii) NADP-GDH also complexes with intracellular ammonium. This second and different form of regulatory complex determines the level of methylammonium uptake by repression or inhibition, or both.

Pateman, J. A.; Kinghorn, J. R.; Dunn, Etta; Forbes, E.

1973-01-01

349

Extraction of the fluoride-, chloride-, and bromide complexes of the elements Nb, Ta, Pa, and 105 into aliphatic amines  

NASA Astrophysics Data System (ADS)

Previous studies of the halide complex formation of element 105 in HCl/HF mixtures and extractions into triisooctyl amine (TIOA) had been performed with the Automated Rapid Chemistry Apparatus, ARCA II. Element 105 was shown to be sorbed on the column from 12 M HCl/0.02 M HF together with its lighter homologues Nb, Ta and the pseudohomologue Pa. In elutions with 10 M HCl/0.025 M HF, 4 M HCl/0.02 M HF, and 0.5 M HCl/0.01 M HF, the extraction sequence Ta>Nb>105>Pa was observed and element 105 behaved very differently from its closest homologue Ta. As it is not possible within reasonable effort to model the many presumably mixed fluoride-chloride complexes involved in these studies, theoretical calculations were performed in the pure chloride system predicting a reversed sequence of extraction. To verify this experimentally, and in order to perform a systematic study of halide complexation of the group 5 elements, new batch extraction experiments for Nb, Ta, and Pa were performed with the quaternary ammonium salt Aliquat 336 in pure HF, HCl, and HBr solutions. Based on these results, new chromatographic column separations were elaborated to study separately the fluoride and chloride complexation of element 105 with ARCA II. In the system Aliquat 336/HF, after feeding of the activity onto the column in 0.5 M HF, element 105 did not elute in 4 M HF (Pa fraction) but showed a higher distribution coefficient close to that of Nb (and Ta). In the system Aliquat 336/HCl, after feeding onto the column in 10 M HCl, element 105 showed a distribution coefficient in 6 M HCl close to that of Nb establishing an extraction sequence Pa>Nb?105>Ta which is theoretically predicted by considering the competition between hydrolysis and complex formation.

Paulus, W.; Kratz, J. V.; Strub, E.; Zauner, S.; Brüchle, W.; Pershina, V.; Schädel, M.; Schausten, B.; Adams, J. L.; Gregorich, K. E.; Hoffman, D. C.; Laue, C.; Lee, D. M.; McGrath, C. A.; Shaughnessy, D. K.; Strellis, D. A.; Sylwester, E. R.

1999-01-01

350

Effects of high concentrations of aqueous tetramethylammonium chloride and other salts on the dissociation of phenylphosphonic acid and on the enolization of acetone  

SciTech Connect

The dissociation constants of benzoic acid and phenylphosphonic acid have been determined in aqueous solutions containing tetramethylammonium chloride at concentrations up to 15 and 13 molal, respectively. The second dissociation constant of phenylphosphonic acid has also been determined in concentrated solutions of alkali halides. Whereas the organic electrolyte increases the observed pK values of the acids, the inorganic electrolytes decrease them. The rate of enolization of acetone, catalyzed by phenylphosphonate dianion is increased by the presence of tetramethylammonium chloride, but is decreased by the presence of inorganic salts, in accordance with the changes in the apparent acidity constants of phenylphosphonate monoanion that the two different kinds of electrolyte bring about. The slope of the Broensted plot for the inorganic salts is 0.76; that for the organic electrolyte is 0.46. Non-quaternary ammonium salts also increase the rate of the phenylphosphonate dianion catalyzed enolization of acetone, but this appears to be due to a considerable extent to the formation of reactive iminium ion intermediates.

Gulinski, J.; Maciejewska, U.; Stewart, R.

1988-04-01

351

Different Sequences Show Similar Quaternary Interaction Stabilities in Prohead Viral RNA Self-assembly*  

PubMed Central

Prohead RNA (pRNA) is an essential component of the self-assembling ?29 bacteriophage DNA packaging motor. Different related species of bacteriophage share only 12% similarity in pRNA sequences. The secondary structure for pRNA is conserved, however. In this study, we present evidence for self-assembly in different pRNA sequences and new measurements of the energetics for the quaternary interactions in pRNA dimers and trimers. The energetics for self-assembly in different pRNA sequences are similar despite very different sequences in the loop-loop interactions. The architecture surrounding the interlocking loops contributes to the stability of the pRNA quaternary interactions, and sequence variation outside the interlocking loops may counterbalance the changes in the loop sequences. Thus, the evolutionary divergence of pRNA sequences maintains not only conservation of function and secondary structure but also stabilities of quaternary interactions. The self-assembly of pRNA can be fine-tuned with variations in magnesium chloride, sodium chloride, temperature, and concentration. The ability to control pRNA self-assembly holds promise for the development of nanoparticle therapeutic applications for this biological molecule. The pRNA system is well suited for future studies to further understand the energetics of RNA tertiary and quaternary interactions, which can provide insight into larger biological assemblies such as viruses and biomolecular motors.

Gu, Xiaobo; Schroeder, Susan J.

2011-01-01

352

Melitracenium chloride.  

PubMed

IN THE TITLE COMPOUND [SYSTEMATIC NAME: 3-(10,10-dimethyl-anthracen-9-yl-idene)-N,N,N-trimethyl-propanaminium chlor-ide], C(21)H(26)N(+)·Cl(-), the cyclo-hexane ring adopts a chair conformation. The dihedral angle between the terminal benzene rings is 40.43?(12)°. In the crystal, ions are linked through inter-molecular N-H?Cl and C-H?Cl hydrogen bonds, forming supra-molecular layers parallel to the bc plane. PMID:21837115

Fun, Hoong-Kun; Hemamalini, Madhukar; Siddegowda, M S; Yathirajan, H S; Narayana, B

2011-06-18

353

Andrei Sher and Quaternary science  

NASA Astrophysics Data System (ADS)

Andrei Sher (1939-2008) was a key individual in Beringian studies who made substantial and original contributions, but also, importantly, built bridges between western and eastern Beringian scientists spanning some five decades of research. He is perhaps best known as a Quaternary palaeontologist, specializing in large mammals, and mammoths in particular, but his field of his scientific research was much broader, encompassing Quaternary geology, stratigraphy, geocryology, and paleoenvironmental reconstructions. He worked mainly in Siberia, in the Kolyma and Indigirka lowlands, and Chukotka, but also completed fieldwork in Alaska and Yukon through joint projects with American and Canadian scientists. Andrei was an active scientist until the last days of his life. He was involved in many different research projects ranging from mammoth evolution, fossil insects and environmental changes and ancient DNA. Without Andrei’s connections between researchers, many unique discoveries would likely be unknown.

Kuzmina, Svetlana; Lister, Adrian M.; Edwards, Mary E.

2011-08-01

354

Quaternary ecology: A paleoecological perspective  

SciTech Connect

This book considers issues and problems in ecology which may be illuminated, if not solved, by considering paleoecology. The five central chapters include a discussion of application of Quaternary ecology to future global climate change, including global warming. Other areas presented include: population dispersal, invasions, expansions, and migrations; plant successions; ecotones; factors in community structure; ecosystem patterns and processes. Published case studies are numerous. The role played by continuing climatic change in vegetation change is acknowledged but not stressed.

Delcourt, H.R.; Delcourt, P.A.

1991-01-01

355

Delivery of a Quaternary Pyridinium Salt Across the Blood-Brain Barrier by Its Dihydropyridine Derivative  

Microsoft Academic Search

A dihydropyridine-pyridine type redox system was successfully applied for delivering a quaternary pyridinium salt, N-methylpyridinium-2-aldoxime chloride (2-PAM), through the blood-brain barrier. The dihydropyridine derivative of 2-PAM was quickly oxidized to 2-PAM after crossing the blood-brain barrier. As a result of this approach, the brain cholinesterase blocked by organophosphates could be reactivated. The new method should be useful in delivering numerous

N. Bodor; E. Shek; T. Higuchi

1975-01-01

356

Characterization of the quaternary amine transporters of Rhizobium leguminosarum bv. viciae 3841.  

PubMed

Rhizobium leguminosarum bv. viciae 3841 contains six putative quaternary ammonium transporters (Qat), of the ABC family. Qat6 was strongly induced by hyperosmosis although the solute transported was not identified. All six systems were induced by the quaternary amines choline and glycine betaine. It was confirmed by microarray analysis of the genome that pRL100079-83 (qat6) is the most strongly upregulated transport system under osmotic stress, although other transporters and 104 genes are more than threefold upregulated. A range of quaternary ammonium compounds were tested but all failed to improve growth of strain 3841 under hyperosmotic stress. One Qat system (gbcXWV) was induced 20-fold by glycine betaine and choline and a Tn5::gbcW mutant was severely impaired for both transport and growth on these compounds, demonstrating that it is the principal system for their use as carbon and nitrogen sources. It transports glycine betaine and choline with a high affinity (apparent K(m), 168 and 294 nM, respectively). PMID:18721149

Fox, Marc A; Karunakaran, Ramakrishnan; Leonard, Mary E; Mouhsine, Bouchra; Williams, Allan; East, Alison K; Downie, J Allan; Poole, Philip S

2008-08-21

357

The anaerobic oxidation of ammonium.  

PubMed

From recent research it has become clear that at least two different possibilities for anaerobic ammonium oxidation exist in nature. 'Aerobic' ammonium oxidizers like Nitrosomonas eutropha were observed to reduce nitrite or nitrogen dioxide with hydroxylamine or ammonium as electron donor under anoxic conditions. The maximum rate for anaerobic ammonium oxidation was about 2 nmol NH4+ min-1 (mg protein)-1 using nitrogen dioxide as electron acceptor. This reaction, which may involve NO as an intermediate, is thought to generate energy sufficient for survival under anoxic conditions, but not for growth. A novel obligately anaerobic ammonium oxidation (Anammox) process was recently discovered in a denitrifying pilot plant reactor. From this system, a highly enriched microbial community with one dominating peculiar autotrophic organism was obtained. With nitrite as electron acceptor a maximum specific oxidation rate of 55 nmol NH4+ min-1 (mg protein)-1 was determined. Although this reaction is 25-fold faster than in Nitrosomonas, it allowed growth at a rate of only 0.003 h-1 (doubling time 11 days). 15N labeling studies showed that hydroxylamine and hydrazine were important intermediates in this new process. A novel type of hydroxylamine oxidoreductase containing an unusual P468 cytochrome has been purified from the Anammox culture. Microsensor studies have shown that at the oxic/anoxic interface of many ecosystems nitrite and ammonia occur in the absence of oxygen. In addition, the number of reports on unaccounted high nitrogen losses in wastewater treatment is gradually increasing, indicating that anaerobic ammonium oxidation may be more widespread than previously assumed. The recently developed nitrification systems in which oxidation of nitrite to nitrate is prevented form an ideal partner for the Anammox process. The combination of these partial nitrification and Anammox processes remains a challenge for future application in the removal of ammonium from wastewater with high ammonium concentrations. PMID:9990725

Jetten, M S; Strous, M; van de Pas-Schoonen, K T; Schalk, J; van Dongen, U G; van de Graaf, A A; Logemann, S; Muyzer, G; van Loosdrecht, M C; Kuenen, J G

1998-12-01

358

Distinct Mechanisms of Block of Kv1.5 Channels by Tertiary and Quaternary Amine Clofilium Compounds  

Microsoft Academic Search

The quaternary ammonium compound clofilium and its tertiary amine derivative LY97241 were used to analyze mechanisms of block in a voltage-gated potassium channel. Wild-type and mutant Kv1.5 channels expressed in Xenopus oocytes were recorded by two-electrode voltage clamp. Open-channel block to 20% of the control current amplitude was induced reversibly by 50?M clofilium or 200?M LY97241, and was seen as

Jill V. Steidl; Andrea J. Yool

2001-01-01

359

Effect of Moisture on Liesegang Ring Formation in Ammonia-Hydrogen Chloride System  

Microsoft Academic Search

IF ammonium chloride is formed by counter-current diffusion of ammonia and hydrogen chloride gases in a long tube, periodic precipitation of the product in the form of rings is observed. This phenomenon has been explained by considering that nucleation and deposition of the product occur only when conditions of super-saturation exist, that is, when the concentration product of the reactants

G. A. Davies; A. B. Ponter; S. Singh

1967-01-01

360

Global modeling of nitrate and ammonium aerosols using EQSAM3  

NASA Astrophysics Data System (ADS)

Atmospheric aerosols, particles suspending in air, are important as they affect human health, air quality, and visibility as well as climate. Sulfate, nitrate, ammonium, chloride and sodium are among the most important inorganic aerosol species in the atmosphere. These compounds are hygroscopic and absorb water under almost all ambient environmental conditions. The uptake of water alters the aerosol size, and causes water to become the constituent with the largest atmospheric aerosol mass, especially when the aerosols grow into fog, haze or clouds. Furthermore, several global model studies have demonstrated that rapid increases in nitrogen emissions could produce enough nitrate in aerosols to offset the expected decline in sulfate forcing by 2100 for the extreme IPCC A2 scenario (Bauer et al., 2007). Although nitrate and ammonium were identified as significant anthropogenic sources of aerosols by a number of modeling studies, most global aerosol models still exclude ammonium-nitrate when the direct aerosol forcing is studied. In this study, the computationally efficient equilibrium model, EQSAM3, is incorporated into the UMICH-IMPACT-nitrate model using the hybrid dynamical solution method (Feng and Penner, 2007). The partitioning of nitrate and ammonium along with the corresponding water uptake is evaluated by comparing the model to the EQUISOLVE II method used in Feng and Penner (2007). The model is also evaluated by comparison with the AERONET data base and satellite-based aerosol optical depths.

Xu, L.; Penner, J. E.

2009-12-01

361

Proposed Regulation: Vinyl Chloride.  

National Technical Information Service (NTIS)

OSHA proposes to regulate producers of vinyl chloride, polyvinyl chloride, and articles made from these substances by requiring that their employees not be exposed to vinyl chloride above specified levels. The major impact of the regulation is expected to...

1974-01-01

362

Poly Iron Chloride and Poly Aluminum Chloride.  

National Technical Information Service (NTIS)

The structures, basic chemistry, preparation procedures, and applications of poly iron chloride (PIC) and poly aluminum chloride (PAC) are presented. PIC and PAC are unconventional inorganic polymers known to be extremely effective for treatment of water ...

L. K. Wang

1987-01-01

363

Evaluation and modeling of benzalkonium chloride inhibition and biodegradation in activated sludge.  

PubMed

The inhibitory effect and biodegradation of benzalkonium chloride (BAC), a mixture of alkyl benzyl dimethyl ammonium chlorides with different alkyl chain lengths, was investigated at a concentration range from 5 to 20 mg/L and different biomass concentrations in an activated sludge system. A solution containing glucose and mineral salts was used as the wastewater in all the assays performed. The inhibition of respiratory enzymes was identified as the mode of action of BAC as a result of oxygen uptake rate analysis performed at BAC concentrations ranging between 5 and 70 mg/L. The glucose degradation in the activated sludge at different BAC and biomass concentrations was well-described with Monod kinetics with competitive inhibition. The half-saturation inhibition constant (K(I)) which is equivalent to EC(50) of BAC for the activated sludge tested ranged between 0.12 and 3.60 mg/L. The high K(I) values were recorded at low BAC-to-biomass ratios, i.e. less than 10 mg BAC/g VSS, at which BAC was almost totally adsorbed to biomass and not bioavailable. BAC degradation started as soon as glucose was totally consumed. Although BAC was almost totally adsorbed on the biomass, it was degraded completely. Therefore, BAC degradation was modeled using two-phase biodegradation kinetics developed in this study. This model involves rapid partitioning of BAC to biomass and consecutive degradation in both aqueous and solid phases. The aqueous phase BAC degradation rate was twenty times, on average, higher than the solid phase degradation rate. The specific aqueous (k(I1)) and solid (k(I2)) phase BAC utilization rate constants were 1.25 and 0.31 mg BAC/g VSS h, respectively. The findings of this study would help to understand the reason of extensive distribution of quaternary ammonium compounds in wastewater treatment plant effluents and in natural water systems although QACs are biodegradable, and develop strategies to avoid their release and accumulation in the environment. PMID:21030060

Zhang, Chong; Tezel, Ulas; Li, Kexun; Liu, Dongfang; Ren, Rong; Du, Jingxuan; Pavlostathis, Spyros G

2010-10-07

364

The Lattice Energies and Transition Temperatures of Cesium-Chloride and Ammonium-Chloride  

Microsoft Academic Search

The lattice energies of CsCl and NH4Cl are calculated for both the CsCl type and NaCl type lattices, and the temperatures of transition between these two crystal forms determined from the equality of the free energies. This requires the computation of the elastic constants and proper frequencies. In determining the lattice energies, use is made of the method of Born

Albert May

1937-01-01

365

Quantitative determination of benzalkonium chloride in treated wood by solid-phase extraction followed by liquid chromatography with ultraviolet detection.  

PubMed

Ammoniacal copper quat (ACQ) compound wood preservative is comprised of copper and quaternary ammonium compounds with benzalkonium chloride (BAC) as the active ingredient. Solid-phase extraction (SPE) followed by liquid chromatography with ultraviolet detection (LC-UV) was developed for quantitative determination of BAC in treated wood. Five species of wood were used, Japanese cedar (Cryptomeria japonica), Japanese larch (Larix leptolepis), Yezo spruce (Picea jezoensis), Sakhalin fir (Abies sachalinensis), and western hemlock (Tsuga heterophylla). BAC used in the present study was composed of 66% C12, 33% C14 and less than 1% C16. BAC was added to each wood species (500 mg) then extracted with HCl-ethanol (20 ml) and quantitatively determined with LC-UV (262 nm). Wood extractives from the heartwood of each species, except western hemlock, interfered with quantitative determination of BAC, but SPE with an Oasis MCX cartridge was effective in preventing this. Using the present methods, BAC homologue peaks were clearly confirmed without interference. Recoveries from wood ranged from 92 to 101% and the limit of quantitation was approximately 240 microg/g wood for the C12 and C14 homologues. PMID:16275285

Miyauchi, Teruhisa; Mori, Mitsunori; Ito, Katsuhiko

2005-10-05

366

Chloride-Initiated Reinforcement Corrosion: Chloride Binding.  

National Technical Information Service (NTIS)

The present report deals with chloride binding, which is one of the mechanisms which determines the service life of the structure with regard to chloride-initiated reinforcement corrosion. The report has been structured so that a model for chloride bindin...

K. Byfors

1990-01-01

367

Negative ion mode electrospray ionization mass spectrometry study of ammonium-counter ion clusters  

Microsoft Academic Search

Electrospray ionization mass spectrometry (ESI-MS) was used to examine clusters of protonated amine salt solutions with chloride\\u000a counter ions in the negative ion mode. These ions have the general formula [(RNH3)xClx+1]?. Primary amines generate a wide cluster distribution with clusters up to 14 mer for methylamine hydrochloride clusters. Secondary\\u000a and quaternary amines only generate the monomer ion under identical conditions.

N. B. Lentz; R. S. Houk

2007-01-01

368

Quaternary glaciation of the Himalayan-Tibetan  

Microsoft Academic Search

Glacial geological evidence from throughout the Himalayan-Tibetan orogen is examined to determine the timing and extent of late Quaternary glaciation in this region and its relation to similar changes on a global scale. The evidence summarised here supports the existence of expanded ice caps and extensive valley glacier systems throughout the region during the late Quaternary. However, it cannot yet

LEWIS A. OWEN; MARC W. CAFFEE; ROBERT C. FINKEL; YEONG BAE SEONG

369

Stereoselective Synthesis of Quaternary Proline Analogues  

PubMed Central

This review describes available methods for the diastereoselective and asymmetric synthesis of quaternary prolines. The focus is on the preparation of ?-functionalized prolines with the pyrrolidine moiety not embedded in a polycyclic frame. The diverse synthetic approaches are classified according to the bond which is formed to complete the quaternary skeleton.

Calaza, M. Isabel

2009-01-01

370

Preparation and characterization of ammonium-functionalized silica nanoparticle as a new adsorbent to remove methyl orange from aqueous solution  

NASA Astrophysics Data System (ADS)

Quaternary ammonium polyethylenimine (PEI) was successfully modified to silica nanoparticle (QPEI/SiO2) as a new adsorbent to remove methyl orange from aqueous solution. The isotherm and kinetics of dye adsorption were studied, which showed that Langmuir isotherm fit the experimental results well. The maximum adsorption capacity of QPEI/SiO2 for methyl orange is 105.4 mg/g. The equilibrium time for methyl orange adsorption onto QPEI/SiO2 was as short as 10 min, indicating that the adsorbent has a strong affinity for methyl orange. The adsorption capacities of the methyl orange are slightly influenced by the pH in the range of 3.2-9.6. The QPEI/SiO2 adsorbent can be used in the wide pH range, which is different from other adsorbent. This may attribute to the quaternary ammonium carrying positive charges in acidic and basic solution.

Liu, Jinshui; Ma, Shi; Zang, Lingjie

2013-01-01

371

Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters.  

PubMed

The concept of anaerobic ammonium oxidation (ANAMMOX) is presently of great interest. The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile, the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite (CANON) have been developed, and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control. Successful full-scale practice in the Netherlands will accelerate application of the process in future. This review introduces the microbiology and more focuses on application of the ANAMMOX process. PMID:18500782

Zhang, Lei; Zheng, Ping; Tang, Chong-jian; Jin, Ren-cun

2008-05-01

372

Hazards analyses of hydrogen evolution and ammonium nitrate accumulation in DWPF -- Revision 1  

SciTech Connect

This revision consists of two reports, the first of which is an analysis of potential ammonium nitrate explosion hazards in the DWPF (Defense Waste Processing Facility). Sections describe the effect of impurities (organic and inorganic (chlorides, chromates, metals and oxides)); the consequences of a hydrogen deflagration or detonation; the role of confinement; the action of heat on ammonium nitrate; the thermal decomposition of ammonium nitrate; the hazard of spontaneous heating; and the explosive decomposition of ammonium nitrate. The second report, Hazard analysis of hydrogen evolution in DWPF: Process vessels and vent system for the late wash/nitric acid flowsheet, contains a description of a revised model for hydrogen generation based on the late wash/nitric acid process. The second part of the report is a sensitivity analysis of the base case conditions and the hydrogen generation model.

Holtzscheiter, E.W.

1994-06-01

373

Effects of Ammonium Metavanadate Treatment Upon Macrophage Glutathione Redox Cycle Activity, Superoxide Production, and Intracellular Glutathione Status  

Microsoft Academic Search

Female B6C3F1 mice were given intraperitoneal injections of ammonium metavanadate (2.5 or 10 mg V\\/Kg), ammonium chloride, or sodium phosphate buffer every 3 days for 6 weeks. Resident peritoneal macrophages were harvested, lysed by freeze-thawing, and the resulting cytolysate was assayed for total protein content and enzyme activities of glutathione reductase, giutathlone peroxidase, and glucose-6-phosphate dehydroge- nase. In addition, peritoneal

M. D. Cohen; C. I. Wei

374

TREATMENT OF AMMONIUM NITRATE SOLUTIONS  

DOEpatents

The treatment of waste solutions obtained in the processing of neutron- irradiated uranium containing fission products and ammonium nitrate is described. The object of this process is to provide a method whereby the ammonium nitrate is destroyed and removed from the solution so as to permit subsequent concentration of the solution.. In accordance with the process the residual nitrate solutions are treated with an excess of alkyl acid anhydride, such as acetic anhydride. Preferably, the residual nitrate solution is added to an excess of the acetic anhydride at such a rate that external heat is not required. The result of this operation is that the ammonium nitrate and acetic anhydride react to form N/sub 2/ O and acetic acid.

Boyer, T.W.; MacHutchin, J.G.; Yaffe, L.

1958-06-10

375

Ammonium nitrogen removal from wastewater with a three-dimensional electrochemical oxidation system.  

PubMed

Ammonium-containing wastewater could cause the promotion of eutrophication and a hindrance to the disinfection of water supplies. In this study, the feasibility of removing low-concentration ammonium nitrogen from synthetic and real wastewater by electrochemical oxidation was investigated. Using laboratory-scale electrochemical systems, the effects of chloride concentration, current density, anode materials, cathode materials, electrode gap, initial ammonium concentration and three-dimensional particles on the removal of ammonium nitrogen and current efficiency (CE) were evaluated. Ammonium nitrogen removal was mainly dependent upon anode materials and current density. The performance of two- and three-dimensional electrochemical oxidation systems was comparatively discussed. Both particle electrodes could enhance ammonium nitrogen removal and increase CE. However, the mechanism of the process seemed to be different. Moreover, the interaction of zeolites adsorption and electrochemical oxidation on the anode in a three-dimensional system could favor the regeneration of zeolites. Surface morphology of the used Ru-Ir-Sn/Ti anode revealed its longer working life of electrocatalysis. The result of ammonium degradation for a real wastewater treatment plant effluent showed the degradation rates in a three-dimensional system increased by 1.4 times those in a two-dimensional system. PMID:23925182

Ding, Jing; Zhao, Qing-Liang; Wei, Liang-Liang; Chen, Yang; Shu, Xin

2013-01-01

376

Influence of ammonium nitrate on kinetics and mechanism of thermal decomposition of ammonium polyuranates  

SciTech Connect

The influence of ammonium nitrate on the mechanism and kinetics of dehydration and thermal decomposition of ammonium polyuranates was studied. An appreciable influence of the nitrate ion content in the samples of ammonium polyuranates on the development of thermal stability has been noted. The kinetic parameters of the thermal decomposition of ammonium polyuranates have been evaluated. A mechanism of the dehydration and thermal decomposition of ammonium polyuranates in the presence of ammonium nitrate has been proposed. It was shown that increase in the content of ammonium nitrate in the precipitate of ammonium polyuranates leads to a decrease in the specific surface of uranoso-uranic oxide.

Karelin, A.I.; Lobas, O.P.; Zhiganov, A.N.; Vasil'ev, K.F.; Zhiganova, A.A.

1988-05-01

377

Coal cleaning employing quaternary salts: Annual report, March 1, 1986-February 28, 1987  

SciTech Connect

Present New Source Performance Standards and the prospect of new acid rain legislation at the federal level require that methods be developed to remove substantial portions of sulfur from Illinois Basin coals. This report describes an innovative approach to coal desulfurization. In this approach, quaternary ammonium salts are employed as catalysts to swell coal. The process is designed to address three basic problems which exist in Illinois Basin coals. First, the pyrite in these coals is at a high level and is very finely dispersed. Therefore, the pyrite particles cannot be liberated by conventional coal cleaning techniques. Second, the porosity of these coals is routinely high but is closed to many reactants because of the lack of feeder and transitional pore structure. Third, the high organic sulfur levels require that some sort of chemical desulfurization occur before most Illinois coals meet NSPS standards. The swelling of coals by quaternary salt results in the liberation of the smallest pyrite and inertinite particles of the coal. Furthermore, cracks occur in the coal particle after swelling. These cracks are associated with the larger size pyrite material embedded in -60 mesh ground coal. Only small amounts of quaternary salt are exchanged on the coal. In some cases, a small amount of exchange results in pore enlargement. Under other conditions, chemical desulfurization of organic sulfur is observed. Relationships between the conditions of exchange, mineral and inertinite liberation, pore enlargement, and coal desulfurization are discussed. The results suggest that: (1) quaternary salts may be used to interrupt oxidation degradation of the coal; (2) coals might be liquified employing specific quaternary salt treatments; and (3) under specific conditions, organic sulfur may be attacked selectively. 3 refs., 22 figs., 30 tabs.

Hippo, E.J.; Sarvela, D.P.; Murdie, N.

1987-05-01

378

Thermal analysis of ammonium diuranate  

Microsoft Academic Search

Thermogravimetric and thermodifferential analyses were used to characterize the behavior during heating of ammonium diuranate (ADU) powders and microspheres. On the basis of a proposed precipitating mechanism of ADU, the main conversion stages of ADU into UâOâ are taken into consideration determining the temperature intervals in which they take place. The approximate composition of intermediate products was also determined. The

C. N. Turcanu; R. Deju

1979-01-01

379

SOURCE ASSESSMENT: AMMONIUM NITRATE PRODUCTION  

EPA Science Inventory

The report describes a study of air pollutants emitted by the ammonium nitrate industry. The potential environmental effect of the source was evaluated. Representative processes and an average plant were defined for the purpose of establishing a base on which to determine the emi...

380

On the Precipitation of Ammonium Polyvanadate.  

National Technical Information Service (NTIS)

Comparatively few studies have been made on ammonium vanadates, especially ammonium polyvanadates, although they are important intermediates in the industrial production of vanadium pentoxide. The effects of crystallization conditions on the nature and pr...

U. M. Levanto

1969-01-01

381

Synthesis and Properties of Piperazine Derivatives and Their Quaternary Ammonium Amphiphilic Salts  

Microsoft Academic Search

A series of long-chain piperazine derivatives,N-alkyl-N?-methyl piperazine and their amphiphilic salts,N-alkyl-N?-ethyl-N?-methyl piperazinium bromide, and the relatedN-alkyl-N,N?-dimethyl piperazinium bromide were synthesized and characterized by1H and13C NMR and FTIR spectroscopy. Under the experimental conditions used, the NMR data showed unequivocally that quaternarization ofN-alkyl-N?-methyl piperazine by the reaction with ethyl bromide occurred exclusively at the nitrogen atom bearing the methyl group due to

L. H. Gan; G. Roshan Deen; Y. Y. Gan; C. H. Chew

1996-01-01

382

Stereoisomeric effect on antimicrobial activity of a series of quaternary ammonium salts  

Microsoft Academic Search

Two homologous series of diastereoisomeric racemic ±cis and ±traps-N,N-dimethyl-N-alkyl-2-benzoyloxycyclohexylmethylammonium bromides with the number of carbon atoms in the alkyl chain from six to twenty (m=6,8...20) were synthesised. Their structures have been elucidated by IR, UV and in some cases also with 1H and 13C NMR spectrometry. The title compounds were assayed for their antimicrobial activity on microorganisms S. aureus, E.

Fridrich Gregan; Jarmila Oremusová; Milan Remko; Juraj Gregan; Dušan Mlynar?ík

1998-01-01

383

Polymeric Bromides, Epoxies, and Quaternary Ammonium Ions to Interact with Cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

Polyethylene and polypropylene glycols are excellent starting materials that interact well with cotton. Our objective is to convert these into reactive entities that either covalently bind or entangle the fiber to raise mechanical strength. In this talk we will discuss the synthesis, structural and ...

384

?????????????????????????????????????????????????????????????? ????????????????????????????????? ?????????? BACTERICIDAL ACTIVITIES OF NOVEL N-SUBSTITUTED CHITOSAN DERIVATIVES CONTAINING QUATERNARY AMMONIUM FUNCTIONALITY  

Microsoft Academic Search

????????: ?????????????????????????????????????????????????????????????????????? ???????????????? ????????????????????????????????? MIC ?????????????????????????????????????????????????????????????????????? 4 ????????????????????????? ?????? ????????? (aliphatic) ????????? (aromatic) ?????????????????????????? ?????????? ??????????????? ????????? (heterocyclic aromatic) ??????? ????????????? (mono, di- saccharides)?????????????????????? Schiff base ????????????????????????????????????????????????????? ?????????????????????????? ????????????????????????? (intermediate) Schiff base ??????????????????? ???????? ?????????????????????????????????? (the extents of N-substitutions; ES) ?????????????????????? ?????????????????????????????????????????????????????????????????? ???? ???????????????????? ?????????????????????????????????? ??????????????????????????????????????????????????????? ???????????? 3-?????-2-???????????????????????????????? ??????? (Quat-188) ??????????? quaternizing agent ????????????????????????????????????????????????????????????????? (MIC) 2 ???? ??? E. coli

William H. Daly; Warayuth Sajomsang; Varawut Tangpasuthadol; Supawan Tantayanon

385

Delimiting the Binding Site for Quaternary Ammonium Lidocaine Derivatives in the Acetylcholine Receptor Channel  

PubMed Central

The triethylammonium QX-314 and the trimethylammonium QX-222 are lidocaine derivatives that act as open-channel blockers of the acetylcholine (ACh) receptor. When bound, these blockers should occlude some of the residues lining the channel. Eight residues in the second membrane-spanning segment (M2) of the mouse-muscle ? subunit were mutated one at a time to cysteine and expressed together with wild-type ?, ?, and ? subunits in Xenopus oocytes. The rate constant for the reaction of each substituted cysteine with 2-aminoethyl methanethiosulfonate (MTSEA) was determined from the time course of the irreversible effect of MTSEA on the ACh-induced current. The reactions were carried out in the presence and absence of ACh and in the presence and absence of QX-314 and QX-222. These blockers had no effect on the reactions in the absence of ACh. In the presence of ACh, both blockers retarded the reaction of extracellularly applied MTSEA with cysteine substituted for residues from ?Val255, one third of the distance in from the extracellular end of M2, to ?Glu241, flanking the intracellular end of M2, but not with cysteine substituted for ?Leu258 or ?Glu262, at the extracellular end of M2. The reactions of MTSEA with cysteines substituted for ?Leu258 and ?Glu262 were considerably faster in the presence of ACh than in its absence. That QX-314 and QX-222 did not protect ?L258C and ?E262C against reaction with MTSEA in the presence of ACh implies that protection of the other residues was due to occlusion of the channel and not to the promotion of a less reactive state from a remote site. Given the 12-? overall length of the blockers and the ?-helical conformation of M2 in the open state, the binding site for both blockers extends from ?Val255 down to ?Ser248.

Pascual, Juan M.; Karlin, Arthur

1998-01-01

386

Interaction between Quaternary Ammonium Ions in the Pore of Potassium Channels  

PubMed Central

We have examined the interaction between internal and external ions in the pore of potassium channels. We found that external tetraethylammonium was able to antagonize block of Shaker channels by internal TEA when the external and internal solutions contained K+ ions. This antagonism was absent in solutions with Rb+ as the only permeant ion. An externally applied trivalent TEA analogue, gallamine, was less effective than the monovalent TEA in inhibiting block by internal TEA. In addition, block by external TEA was little affected by changes in the concentration of internal K+ ions, but was increased by the presence of internal Na+ ions in the pore. These results demonstrate that external and internal TEA ions, likely located at opposite ends of the pore selectivity filter, do not experience a mutual electrostatic repulsion. We found that these results can be simulated by a simple 4-barrier-3-site permeation model in which ions compete for available binding sites without long-range electrostatic interactions.

Thompson, Jill; Begenisich, Ted

2000-01-01

387

New water disinfectant: an insoluble quaternary ammonium resin-triiodide combination that releases bactericide on demand.  

PubMed

Strongly basic anion-exchange resins form stable, water-insoluble combinations with triiodide ions. The combinations have remarkable antibacterial properties: 3.0 x 10(5)Escherichia coli cells per ml were killed when passed through a 3.8-g column of commercially available resin treated with triiodide (volume 4 ml after treatment). In an attempt to deplete the resin-triiodide complex, 1.14 x 10(9)E. coli cells in 15 liters were passed through the column with no significant loss of effectiveness. The antibacterial capabilities of the resin-triiodide columns ranged from 10(6)Salmonella typhimurium per ml to 1.1 x 10(4)Streptococcus faecalis per ml. Staphylococcus aureus and Pseudomonas aeruginosa were also tested and killed at concentrations of 1.8 x 10(4) and 1.3 x 10(5) per ml, respectively. The cells were not filtered from the water. They emerged from the column in nonviable form. This was demonstrated by using (14)C-labeled bacteria. The irreversible nature of the antibacterial action was revealed when attempts to wash the damaged cells did not restore viability. PMID:4991917

Taylor, S L; Fina, L R; Lambert, J L

1970-11-01

388

Surface modification and antibacterial activity of electrospun polyurethane fibrous membranes with quaternary ammonium moieties  

Microsoft Academic Search

A novel antibacterial material was developed by surface modification of electrospun polyurethane (PU) fibrous membranes, using a process which involved plasma pretreatment, UV-induced graft copolymerization of 4-vinylpyridine (4VP), and quaternization of the grafted pyridine groups with hexylbromide. The success of modification with poly(4-vinyl-N-hexyl pyridinium bromide) groups on these was ascertained by X-ray photoelectron spectroscopy (XPS). The morphologies and mechanical properties

Chen Yao; Xinsong Li; K. G. Neoh; Zhilong Shi; E. T. Kang

2008-01-01

389

40 CFR 721.10666 - Quaternary ammonium compounds, bis(fattyalkyl) dimethyl, salts with tannins (generic).  

Code of Federal Regulations, 2013 CFR

...bis(fattyalkyl) dimethyl, salts with tannins (generic). 721.10666 Section...bis(fattyalkyl) dimethyl, salts with tannins (generic). (a) Chemical substance...bis(fattyalkyl) dimethyl, salts with tannins (PMN P-12-437) is subject to...

2013-07-01

390

The reaction of C -phenylcalix[4]resorcinarene-based polymer with quaternary ammonium and potassium cations  

Microsoft Academic Search

The resol polycondensation ofC-phenylcalix[4]resorcinarene with formaldehyde affords a corss-linked polymer possessing ion-exchange ability. The ion-exchange\\u000a capacity of the polymer with respect to NH4\\u000a +, Me4N+, Et4N+, Bu4N+, and K+ cations was determined. The equilibrium in the systemsC-phenylcalix[4]resorcinarene-based polymer—binary or ternary aqueous solutions of electrolytes was studied by potentiometric\\u000a titration and quantumchemical MNDO\\/PM3 calculation

G. N. Al'tshuler; O. N. Fedyaeva; E. V. Ostapova

2000-01-01

391

Supramolecular assembly of borate with quaternary ammonium: Crystal structure and tunable luminescent properties  

NASA Astrophysics Data System (ADS)

A new borate [C6H16N][B5O6(OH)4] (1) is synthesized hydrothermally by the reaction of isopropyltrimethylammonium hydroxide with boric acid. It crystallizes in the triclinic space group P-1 with the parameters a=9.1578(10) Å, b=9.372(9) Å, c=9.9812(10) Å, ?=66.508(2)°, ?=74.751(2)°, ?=81.893(2)°. The [B5O6(OH)4]- anions are interlinked via hydrogen bonding forming a 3D supramolecular network containing large cavities, where reside the (CH3)3(i-C3H7) N+ cations. This borate shows tunable luminescent properties with temperature, heating-treatment, exciting-light, and solvents. The fluorescent intensity of 1 enhances 6-fold with decreasing the temperature from 25 K to 78 K. By treatment under different temperatures, the luminescence of 1 shifted from blue to white and the sample treated at 230 °C emits bright white light to naked eyes. The hybrid borate can disperse in different solvents, and shows a red-shifted and intense emission in polar solvents.

Liang, Jie; Wang, Yong-gang; Wang, Ying-xia; Liao, Fu-hui; Lin, Jian-hua

2013-04-01

392

Structure-activity relationship for quaternary ammonium compounds hybridized with poly(methyl methacrylate).  

PubMed

Hybrid films from poly (methylmethacrylate) (PMMA) and dioctadecyldimethylammonium bromide (DODAB), cetyltrimethylammonium bromide (CTAB), or tetrapropylammonium bromide (TPAB) were characterized by determination of wettability, ellipsometry, atomic force microscopy, active compounds diffusion to water, X-ray photoelectron spectroscopy (XPS) with determination of atomic composition on the films surface, and biocidal activity against Pseudomonas aeruginosa or Staphylococcus aureus. QAC mobility in the films increased from DODAB to CTAB to TPAB. Diffusion and optimal hydrophobic-hydrophilic balance imparted the highest bioactivity to CTAB. DODAB sustained immobilization at the film surface killed bacteria upon contact. TPAB ability to diffuse was useless because of its unfavorable hydrophobic-hydrophilic balance for bioactivity. PMID:21591705

Melo, Leticia D; Palombo, Renata R; Petri, Denise F S; Bruns, Michael; Pereira, Edla M A; Carmona-Ribeiro, Ana M

2011-05-27

393

21 CFR 184.1137 - Ammonium carbonate.  

Code of Federal Regulations, 2010 CFR

...is a mixture of ammonium bicarbonate (NH4 HCO3 ) and ammonium carbamate (NH2 COONH4 ). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs as a white powder or a hard, white or translucent...

2009-04-01

394

21 CFR 184.1137 - Ammonium carbonate.  

Code of Federal Regulations, 2013 CFR

...is a mixture of ammonium bicarbonate (NH4 HCO3 ) and ammonium carbamate (NH2 COONH4 ). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs as a white powder or a hard, white or translucent...

2013-04-01

395

21 CFR 184.1137 - Ammonium carbonate.  

Code of Federal Regulations, 2010 CFR

...is a mixture of ammonium bicarbonate (NH4 HCO3 ) and ammonium carbamate (NH2 COONH4 ). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs as a white powder or a hard, white or translucent...

2010-01-01

396

21 CFR 184.1133 - Ammonium alginate.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Ammonium alginate. 184.1133 Section 184.1133 Food and...Substances Affirmed as GRAS § 184.1133 Ammonium alginate. (a) Ammonium alginate (CAS Reg. No. 9005-34-9) is the...

2010-01-01

397

Didecyldimethylammonium chloride induces pulmonary fibrosis in association with TGF-? signaling in mice.  

PubMed

Didecyldimethylammonium chloride (DDAC) is a representative dialkyl-quaternary ammonium compound that is used as a disinfectant against several pathogens and is also used in commercial, industrial, and residential settings. We previously investigated toxicity on air way system following single instillation of DDAC to the lungs in mice, and found that DDAC causes pulmonary injury, which is associated with altered antioxidant antimicrobial responses; the inflammatory phase is accompanied or followed by fibrotic response. The present study was conducted to monitor transforming growth factor-? (TGF-?) signaling in pulmonary fibrosis induced by DDAC. Mice were intratracheally instilled with DDAC and sacrificed 1, 3, or 7 days after treatment to measure TGF-? signaling. In order to further evaluate TGF-? signaling, we treated isolated mouse lung fibroblasts with DDAC. Fibrotic foci were observed in the lungs on day 3, and were widely extended on day 7, with evidence of increased ?-smooth muscle actin-positive mesenchymal cells and upregulation of Type I procollagen mRNA. Developing fibrotic foci were likely associated with increased expression of Tgf-?1 mRNA, in addition to decreased expression of Bone morphogenetic protein-7 mRNA. In fibrotic lung samples, the expression of phosphorylated SMAD2/3 was considerably higher than that of phosphorylated SMAD1/5. In isolated lung fibroblasts, the mRNA levels of Tgf-?1 were specifically increased by DDAC treatment, which prolonged phosphorylation of SMAD2/3. These effects were abolished by treatment with SD208 - a TGF-?RI kinase inhibitor. The results suggest that DDAC induces pulmonary fibrosis in association with TGF-? signaling. PMID:23537712

Ohnuma-Koyama, Aya; Yoshida, Toshinori; Tajima-Horiuchi, Haruka; Takahashi, Naofumi; Yamaguchi, Satoru; Ohtsuka, Ryoichi; Takeuchi-Kashimoto, Yukiko; Kuwahara, Maki; Takeda, Makio; Nakashima, Nobuaki; Harada, Takanori

2013-03-26

398

CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT WITH SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

399

Mercuric chloride poisoning  

MedlinePLUS

Mercuric chloride is a very poisonous form of mercury. It is a type of mercury salt. There are different ... poisonings . This article discusses poisoning from swallowing mercuric chloride. This is for information only and not for ...

400

Dehydration of Magnesium Chloride.  

National Technical Information Service (NTIS)

The patent application discloses a method for dehydrating magnesium chloride hydrates or brines by complexing with amine hydrochlorides. Magnesium chloride hydrate or brine is reacted to an amine hydrochloride to form a complex which is then heated to fir...

H. Dolezal

1975-01-01

401

Chloride Removal Implementation Guide.  

National Technical Information Service (NTIS)

Equipment and procedures for the electrochemical removal of chloride from reinforced concrete structures are described. The guide provides basic information needed to implement the chloride removal process of field structures. Pretreatment and posttreatme...

J. Bennett T. J. Schue

1993-01-01

402

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.  

Code of Federal Regulations, 2010 CFR

...nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 ...nitrates, and certain ammonium nitrate fertilizers. (a) Except as provided in...Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than 70%...

2010-10-01

403

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.  

Code of Federal Regulations, 2010 CFR

...nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 ...nitrates, and certain ammonium nitrate fertilizers. (a) Except as provided in...Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than 70%...

2009-10-01

404

Chloride in smooth muscle  

Microsoft Academic Search

Interest in the functions of intracellular chloride expanded about twenty years ago but mostly this referred to tissues other than smooth muscle. On the other hand, accumulation of chloride above equilibrium seems to have been recognised more readily in smooth muscle.Experimental data is used to show by calculation that the Donnan equilibrium cannot account for the chloride distribution in smooth

A. R. Chipperfield; A. A. Harper

2000-01-01

405

Quaternary tectonics of the southeastern coastal area, Korea: subsidence of marine terrace and late Quaternary faults  

Microsoft Academic Search

Strong earthquake has rarely occurred in Korean peninsula and a few events were recorded since 27 A.D. Historical and recent earthquakes are concentrated in the southeastern area of Korean peninsula, where more than 30 Quaternary fault exposures have recently been founded. The southern tip of the southeastern coastal area has been known as a stable block: quaternary fault and micro-earthquakes

S.-J. Choi; Y. Ota; U. Chwae

2003-01-01

406

X-Ray and Thermal Analysis of Quenched Ammonium Fluoride II and III: Three New Phases  

Microsoft Academic Search

Ammonium fluoride II and III have been recovered at 100°K and atmospheric pressure and examined by x-ray powder diffraction and by thermal analysis. The structure of phase III is closely related to that of cesium chloride. Phase II when heated from 100°K at atmospheric pressure transforms to a new phase, designated V, at about 120°K and V in turn transforms

M. A. Nabar; L. D. Calvert; E. Whalley

1969-01-01

407

Ambient ammonia and ammonium aerosol across a region of variable ammonia emission density  

Microsoft Academic Search

We present 1 year of ambient ammonia (NH3), ammonium (NH4+), hydrochloric acid (HCl), chloride (Cl?), nitric acid (HNO3), nitrate (NO3?), nitrous acid (HONO), sulfur dioxide (SO2), and sulfate (SO42?) concentrations at three sites in the Coastal Plain region of North Carolina. The three sites, Clinton, Kinston, and Morehead City, are located in counties with total NH3 emission densities of 4800,

J. T. Walker; Dave R Whitall; Wayne Robarge; Hans W. Paerl

2004-01-01

408

(4-Meth-oxy-phen-yl)methanaminium chloride.  

PubMed

In the crystal structure of the title salt, C(8)H(12)NO(+)·Cl(-), the methoxy group of the cation is co-planar with the phenylene moiety with an r.m.s. deviation from the mean plane of only 0.005?Å. The ammonium N atom deviates from this plane by 1.403?(1)?Å. In the crystal, the (4-meth-oxy-phen-yl)methan-aminium cations and chloride anions are linked by N-H?Cl and C-H?O hydrogen bonds, resulting in an open framework architecture with hydrogen-bonded ammonium groups and chloride anions located in layers parallel to (011), separated by more hydrophobic layers with interdigitating anisole groups. PMID:21522388

Kefi, Riadh; Matthias, Zeller; Ben Nasr, Cherif

2011-02-16

409

Determination of benzethonium chloride in anthrax vaccine adsorbed by HPLC  

Microsoft Academic Search

A novel and sensitive HPLC method for the determination of benzethonium chloride (BZC) in anthrax vaccine was developed. Adjuvant Alhydrogel was removed by syringe filter after a simple sample pretreatment—acidification prior to injection. Chromatography was performed by isocratic reverse phase separation with methanol\\/262mM ammonium acetate (80\\/20, v\\/v) on an endcapped C18 column with diode array detector (DAD). The method showed

Hsiaoling Wang; Alfred V. Del Grosso; Joan C. May

2006-01-01

410

ANAEROBIC AMMONIUM OXIDATION IN THE MARINE ENVIRONMENT  

Microsoft Academic Search

Oceanographers noticed already many years ago that far less ammonium accumulated in anoxic fjords and basins, than would be\\u000a expected from the stoichiometry of heterotrophic denitrification. It was suggested that this ‘missing’ ammonium was oxidized\\u000a with nitrate to freeN2. Since then several otherworkers have argued based on chemical profiles that ammonium is oxidized anaerobically in oxygen\\u000a deficient marine sediments and

Marcel M. M. Kuypers; Gaute Lavik; Bo Thamdrup

411

Physiological aspects of ammonium and nitrate fertilization  

Microsoft Academic Search

Various physiological effects of ammonium, nitrate and mixed ammonium?nitrate nutrition of plants have been studied in this laboratory during the last years. Some of the characteristic distinctions observed between plants growing on these nitrogen sources are described and discussed. Biomass production of ammonium?grown plants increased with K concentration in the nutrient medium between 0.1 to 3 mM , while nitrate?fed

S. H. Lips; E. O. Leidi; M. Silberbush; M. I. M. Soares; O. E. M. Lewis

1990-01-01

412

Quaternary Marine Sulfur Cycle Dynamics  

NASA Astrophysics Data System (ADS)

Published data show a -0.8% change in marine sulfate ?34S ratios in the past 2 Ma. Prior to this period it was stable at ~ 22% for ~ 50Ma since the Eocene. Compared to the residence time of sulfate (>10 Ma) the observed change is large and implies a major disturbance of the marine sulfur cycle. However, the cause of the disturbance, as well as the timing of its onset are poorly constrained. Here we present a new set of ?34S ratios of marine sulfate for the last 3 Ma with a temporal resolution of ~300ka, which shows a linear decline from 22 to ~21% in the past 1.75Ma. This may represent a change in volcanic and hydrothermal activity, pyrite burial or erosion and weathering of exposed evaporites and sulfides, which are the main processes affecting sulfate ?34S. However, during this period there is no geological evidence for exceptional volcanic and hydrothermal activity and consequently, the observed negative shift reflects either a change in isotopic composition and volume of erosional input of sulfate to the ocean, or a decrease in pyrite burial. The isotopic composition of the input flux depends on the relative proportion of sulfide vs. sulfate weathering. Sedimentary sulfides are mostly concentrated in organic rich sediments on continental shelves. Existing sea level records suggest periodic sea level drops during glacial stages related to the formation of ice sheets. This could affect sulfur cycling in two ways: a) exposure to surface weathering and erosion agents of large parts of continental shelves increased global sulfide oxidation and thus the input flux of sulfate to the ocean and/or b) the reduction of shelf areas resulted in decreased pyrite burial. We explore the effects of these changes with a simple box model. The modeling results indicate that the observed isotopic shift requires a 150% increase of pyrite weathering or a 90% reduction of pyrite burial over the past 1.75Ma. When both of these processes change in concert the same effect is produced with the doubling of pyrite weathering and 50% decrease of pyrite burial. As pyrite burial and organic matter burial are intimately linked, a drastic decrease in pyrite burial should leave its mark in the carbon isotopic record which shows no evidence of a major change in carbon cycling. We thus propose that increased sulfide weathering, either from subaerial exposure, or as a result of increased winnowing might be the principal cause of the negative ?34S shift in the Quaternary.

Markovic, S.; Paytan, A.; Wortmann, U. G.

2011-12-01

413

40 CFR 721.10569 - Tricyclic quaternary amine salt (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Tricyclic quaternary amine salt (generic). 721.10569 Section 721...721.10569 Tricyclic quaternary amine salt (generic). (a) Chemical substance...generically as tricyclic quaternary amine salt (PMN P-08-471) is subject to...

2013-07-01

414

Effect of ammonium nitrate on precipitation of Ammonium Di-Uranate (ADU) and its characteristics  

NASA Astrophysics Data System (ADS)

Scanning Electron Microscopic (SEM) images of ADU prepared with gaseous ammonia, (a) in presence of excess ammonium nitrate (80 g/L) as well as (b) in absence of excess ammonium nitrate at different magnification.

Paik, Shrishma; Biswas, S.; Bhattacharya, S.; Roy, S. B.

2013-09-01

415

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.  

Code of Federal Regulations, 2012 CFR

...more than 70 percent of ammonium nitrate and a maximum of 0.4 percent combustible material; (2) Ammonium nitrate with calcium carbonate and/or dolomite, containing more than 80 percent but less than 90 percent of ammonium nitrate and a maximum...

2012-10-01

416

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.  

Code of Federal Regulations, 2011 CFR

...more than 70 percent of ammonium nitrate and a maximum of 0.4 percent combustible material; (2) Ammonium nitrate with calcium carbonate and/or dolomite, containing more than 80 percent but less than 90 percent of ammonium nitrate and a maximum...

2011-10-01

417

An electronic tongue designed to detect ammonium nitrate in aqueous solutions.  

PubMed

An electronic tongue has been developed to monitor the presence of ammonium nitrate in water. It is based on pulse voltammetry and consists of an array of eight working electrodes (Au; Pt; Rh; Ir; Cu; Co; Ag and Ni) encapsulated in a stainless steel cylinder. In a first step the electrochemical response of the different electrodes was studied in the presence of ammonium nitrate in water in order to further design the wave form used in the voltammetric tongue. The response of the electronic tongue was then tested in the presence of a set of 15 common inorganic salts; i.e.; NH4NO3; MgSO4; NH4Cl; NaCl; Na2CO3; (NH4)2SO4; MgCl2; Na3PO4; K2SO4; K2CO3; CaCl2; NaH2PO4; KCl; NaNO3; K2HPO4. A PCA plot showed a fairly good discrimination between ammonium nitrate and the remaining salts studied. In addition Fuzzy Art map analyses determined that the best classification was obtained using the Pt; Co; Cu and Ni electrodes. Moreover; PLS regression allowed the creation of a model to correlate the voltammetric response of the electrodes with concentrations of ammonium nitrate in the presence of potential interferents such as ammonium chloride and sodium nitrate. PMID:24145916

Campos, Inmaculada; Pascual, Lluis; Soto, Juan; Gil-Sánchez, Luis; Martínez-Máez, Ramón

2013-10-18

418

Stability of allophycocyanin's quaternary structure  

SciTech Connect

The dissociation of allophycocyanin trimers to monomers was examined under a variety of conditions. For alkyl ureas and alcohols the dissociation increased as the straight-chain alkyls increased in length. The effect of branching chains was smaller. Tetrapropylammonium chloride was found to be a very effective agent for trimer dissociation when compared to ureas and alcohols with similar or longer alkyl chains. An explanation for these observations is that the hydrocarbons have an affinity for nonpolar regions in the contact areas between monomers in a trimeric structure. A comparison among several inorganic salts demonstrated that the chaotropic salts (NaSCN greater than NaClO/sub 4/ much greater than NaNO/sub 3/ greater than NaBr) fostered increased trimer dissociation, while nonchaotropes (KF, (NH/sub 4/)/sub 2/SO/sub 4/, K phosphate, and NaCl) produced no measurable amounts of monomer. Allophycocyanin dissolved in D/sub 2/O was much more stable against dissociation than when dissolved in H/sub 2/O. All the above observations were consistent with hydrophobic forces being the dominant source of trimer stabilization. The equilibrium constant for the dissociation of trimers to monomers was calculated to be about 6 X 10(-16) mol2 liter-2. Calculations were made of the apparent total number of amino acids (40) in the two contact regions on each monomer.

MacColl, R.

1983-01-01

419

Quaternary cave levels in peninsular Florida  

Microsoft Academic Search

The hypothesis that caves in the Florida Peninsula are tied to Quaternary sea levels was proposed by hydrogeologists, without data, some 40 years ago. The hypothesis is a version of glacial control of cave levels, which is the logical combination of the water-table theory of speleogenesis and the concept that base level positions the water table. At the USA type

Lee J. Florea; H. L. Vacher; Brian Donahue; David Naar

2007-01-01

420

Quaternary glaciation of the Himalaya and Tibet  

Microsoft Academic Search

Glacial geological evidence from throughout the Himalaya-Tibet shows the existence of expanded ice caps and extensive valley glacier systems during the late Quaternary. Whether the timing of the extent of maximum glaciation was synchronous throughout the entire region or whether the response was more varied is a topic of much contention. This is mainly because the lack of organic material

L. A. Owen

2008-01-01

421

Hydrogen Chloride Sparging Crystallization of Aluminum Chloride Hexahydrate.  

National Technical Information Service (NTIS)

As part of its effort to produce cell-grade alumina from clay, the Bureau of Mines investigated the hydrogen chloride gas-sparging crystallization of aluminum chloride hexahydrate (ACH) from aluminum chloride liquor, to provide information for optimizing ...

D. E. Shanks D. J. Bauer J. A. Eisle

1982-01-01

422

The Influence of the Anionic Counter-Ion on the Activity of Ammonium Substituted Hoveyda-Type Olefin Metathesis Catalysts in Aqueous Media  

NASA Astrophysics Data System (ADS)

Polar olefin metathesis catalysts, bearing an ammonium group are presented. The electron withdrawing ammonium group not only activates the catalysts electronically, but at the same time makes the catalysts more hydrophilic. Catalysts can be therefore efficiently used not only in traditional media, such as methylene chloride and toluene, but also in technical-grade alcohols, alcohol— water mixtures and in neat water. Finally, in this overview the influence of the anionic counter-ion on the activity of ammonium substituted Hoveyda-type olefin metathesis catalysts in aqueous media is presented.

Gu?ajski, ?ukasz; Grela, Karol

423

21 CFR 556.375 - Maduramicin ammonium.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS TOLERANCES...of maduramicin ammonium in chickens as follows: (a) A tolerance...ammonium (marker residue) in chickens is 0.38 parts per million...residues in uncooked edible chicken tissues are: 0.24...

2013-04-01

424

Influence of ammonium uptake on bean nutrition  

Microsoft Academic Search

A glasshouse experiment was carried out in order to study the effect of ammonium supply [0 and 1.5 mmol L in the nutrient solution, whereas total nitrogen (N) concentration was 9.5 mmol L] on nutrient uptake, leaves, and xylem sap composition and growth of bean plants in sand culture. Ammonium supply caused higher nitrogen, phosphorus (P), potassium (K), and calcium

M. J. Sarro; J. M. Sánchez; J. M. Peñalosa

1998-01-01

425

Platinized Silver Chloride Electrode  

Microsoft Academic Search

A hybrid electrode made by platinizing silver-silver chloride has been found to combine the stable potential and low direct-current resistance properties of a silver-silver chloride electrode with the low high-frequency impedance characteristic of a platinized platinum electrode.

Kenneth S. Cole; Uichiro Kishimoto

1962-01-01

426

Efficient siRNA delivery based on PEGylated and partially quaternized polyamine nanogels: enhanced gene silencing activity by the cooperative effect of tertiary and quaternary amino groups in the core.  

PubMed

For the development of an siRNA delivery system using polyion complexes (PICs) based on PEGylated nanogel consisting of a cross-linked poly[2-(N,N-diethylaminoethyl) methacrylate] (PEAMA) gel core and tethered poly(ethylene glycol) (PEG) chains, quaternary ammonium groups were introduced in the polyamine gel core to enhance the binding ability with siRNA and the stability of the PICs. Consequently, the quaternization of the polyamine core of the nanogel facilitated the binding ability with siRNA at a low N/P ratio, and the stability against polyanion displacement was enhanced as the degree of quaternization (DQ) of the nanogel increased. Although the installation of the positively charged quaternary ammonium moieties in the core of the nanogel resulted in the increment of the xi-potential of the PICs (e.g. + 23 mV for DQ=100%), the cytotoxicity was reduced with the increase of DQ presumably due to the hydrophilic character of the quaternary ammonium groups. The installation of quaternary ammonium groups in the core of the nanogel enhanced the endogenous gene silencing activity against the survivin gene in human hepatocarcinoma (HuH-7 cells), especially, the partly quaternized polyamine nanogel (DQ=10%) showed the highest gene silencing ability among the quaternized polyamine nanogels, including the tertiary amine nanogel. The cellular uptake analysis of the Rhodamine B-labeled Q-nanogel/fluorescein-labeled siRNA complex revealed that the quaternization of PEAMA moieties enhanced the cellular uptake level of fluorescein-labeled siRNA with the increase in DQ, whereas the cellular uptake of the Rhodamine B-labeled Q-nanogels was almost of the same level regardless of the DQ value, indicating that significant cellular uptake of the fluorescein-labeled siRNA is most likely due to the enhancement of the binding ability with siRNA in the serum-containing medium. Note that the endosomal escape efficiency was reduced with increase in the DQ value due to the decrease in the buffering capacity (tertiary amino groups) of the PEAMA core. On the basis of these results, the ratio of quaternary ammonium groups to tertiary amino groups in the core of the nanogel plays a pivotal role in the achievement of significant gene silencing through enhanced cellular uptake (quaternary ammonium groups) and subsequent endosomal escape (tertiary amino groups). PMID:20621664

Tamura, Atsushi; Oishi, Motoi; Nagasaki, Yukio

2010-06-04

427

Physiological and phylogenetic study of an ammonium-oxidizing culture at high nitrite concentrations.  

PubMed

Oxidation of high-strength ammonium wastewater can lead to exceptionally high nitrite concentrations; therefore, the effect of high nitrite concentration (> 400 mM) was studied using an ammonium-oxidizing enrichment culture in a batch reactor. Ammonium was fed to the reactor in portions of 40-150 mM until ammonium oxidation rates decreased and finally stopped. Activity was restored by replacing half of the medium, while biomass was retained by a membrane. The ammonium-oxidizing population obtained was able to oxidize ammonium at nitrite concentrations of up to 500 mM. The maximum specific oxidation activity of the culture in batch test was about 0.040 mmol O(2)g(-1)proteinmin(-1) and the K(s) value was 1.5 mM ammonium. In these tests, half of the maximum oxidation activity was still present at a concentration of 600 mM nitrite and approximately 10% residual activity could still be measured at 1200 mM nitrite (pH 7.4), or as a free nitrous acid (FNA) concentration of 6.6 mg l(-1). Additional experiments showed that the inhibition was caused by nitrite and not by the high sodium chloride concentration of the medium. The added ammonium was mainly converted into nitrite and no nitrite oxidation was observed. In addition, gaseous nitrogen compounds were detected and mass balance calculations revealed a nitrogen loss of approximately 20% using this system. Phylogenetic analyses of 16S rRNA and ammonium monooxygenase (amoA) genes of the obtained enrichment culture showed that ammonium-oxidizing bacteria of the Nitrosomonas europaea/Nitrosococcus mobilis cluster dominated the two clone libraries. Approximately 25% of the 16S rRNA clones showed a similarity of 92% to Deinococcus-like organisms. Specific fluorescence in situ hybridization (FISH) probes confirmed that these microbes comprised 10-20% of the microbial community in the enrichment. The Deinococcus-like organisms were located around the Nitrosomonas clusters, but their role in the community is currently unresolved. PMID:18289820

Tan, Nico C G; Kampschreur, Marlies J; Wanders, Wouter; van der Pol, Willem L J; van de Vossenberg, Jack; Kleerebezem, Robbert; van Loosdrecht, Mark C M; Jetten, Mike S M

2008-03-04

428

40 CFR 721.10099 - Dialkyl dimethyl ammonium carbonate (generic).  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Dialkyl dimethyl ammonium carbonate (generic). 721.10099...721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a...generically as dialkyl dimethyl ammonium carbonate (1:1) (PMN...

2009-07-01

429

40 CFR 721.10099 - Dialkyl dimethyl ammonium carbonate (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Dialkyl dimethyl ammonium carbonate (generic). 721.10099...721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a...generically as dialkyl dimethyl ammonium carbonate (1:1) (PMN...

2013-07-01

430

40 CFR 721.10099 - Dialkyl dimethyl ammonium carbonate (generic).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Dialkyl dimethyl ammonium carbonate (generic). 721.10099...721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a...generically as dialkyl dimethyl ammonium carbonate (1:1) (PMN...

2010-07-01

431

78 FR 32690 - Certain Ammonium Nitrate From Ukraine  

Federal Register 2010, 2011, 2012, 2013

...Review)] Certain Ammonium Nitrate From Ukraine Determination On the basis of the record...order on certain ammonium nitrate from Ukraine would be likely to lead to continuation...entitled Certain Ammonium Nitrate from Ukraine: Investigation No....

2013-05-31

432

40 CFR 721.10302 - Zinc ammonium phosphate (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Zinc ammonium phosphate (generic). 721...Specific Chemical Substances § 721.10302 Zinc ammonium phosphate (generic). ...chemical substance identified generically as zinc ammonium phosphate (PMN...

2013-07-01

433

Modified Ammonium Perchlorate Incorporating Potassium, Permanganate, and Dichromate Dopants.  

National Technical Information Service (NTIS)

The present study of ammonium perchlorate which is grown as whisker crystals from porous glass by a recently discovered process is extended to doped ammonium perchlorate. The selection of dopants in whisker ammonium perchlorate is limited initially to tho...

A. Adicoff W. M. Ayres M. E. Hills W. R. McBride

1971-01-01

434

21 CFR 582.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2011 CFR

...2013-04-01 2013-04-01 false Aluminum ammonium sulfate. 582.1127 Section...General Purpose Food Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

2013-04-01

435

21 CFR 182.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2012 CFR

...2013-04-01 2013-04-01 false Aluminum ammonium sulfate. 182.1127 Section...Purpose GRAS Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

2013-04-01

436

21 CFR 182.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Aluminum ammonium sulfate. 182.1127 Section 182.1127...Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions of use....

2009-04-01

437

21 CFR 582.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127...Food Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions of use....

2009-04-01

438

21 CFR 182.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Aluminum ammonium sulfate. 182.1127 Section 182.1127...Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions of use....

2010-01-01

439

Recovery of high purity copper cathode from printed circuit boards using ammoniacal sulfate or chloride solutions  

Microsoft Academic Search

The behavior of impurity elements during a copper recovery process from waste printed circuit board (PCB) using ammonia–ammonium sulfate and chloride systems are examined and the performance of these two systems are compared. Leaching of PCB was carried out by solutions containing copper(II) ammine complexes as the oxidizing agent. The copper was selectively dissolved but the leach solution also contained

T. Oishi; K. Koyama; S. Alam; M. Tanaka; J.-C. Lee

2007-01-01

440

Structural study of ammonium metatungstate  

NASA Astrophysics Data System (ADS)

Several techniques have been used to study the structure of the Keggin-type polyoxometalate salt ammonium metatungstate (AMT)—(NH4)6[H2W12O40]*nH2O, a potential fuel cell catalyst. The dehydrated salt is comprised of a mixture of crystallites of different unit cells in a centered eutactic cubic configuration, with an average unit cell of a?12.295. Varied orientations of the Keggin ions in the cubic arrangement create the differences, and orientational variation within each unit cell size represents an energy well. Progressive hydration of each crystallite leads to expansion of the lattice, with the degree of expansion depending on the locations of the water added in relation to the Keggin ion, which is influenced by cation location and hydrogen bonding. The structural hypothesis is supported by electron diffraction of single and multicrystal samples, by powder density measurements, X-ray powder diffraction studies, synchrotron powder X-ray diffraction, and a priori structural modeling studies. Based on the structure, projected active site densities are compared with nanostructured platinum catalysts for fuel cell application.

Christian, Joel B.; Whittingham, M. Stanley

2008-08-01

441

Substrate specificity of Rhbg: ammonium and methyl ammonium transport  

PubMed Central

Rhbg is a nonerythroid membrane glycoprotein belonging to the Rh antigen family. In the kidney, Rhbg is expressed at the basolateral membrane of intercalated cells of the distal nephron and is involved in NH4+ transport. We investigated the substrate specificity of Rhbg by comparing transport of NH3/NH4+ with that of methyl amine (hydrochloride) (MA/MA+), often used to replace NH3/NH4+, in oocytes expressing Rhbg. Methyl amine (HCl) in solution exists as neutral methyl amine (MA) in equilibrium with the protonated methyl ammonium (MA+). To assess transport, we used ion-selective microelectrodes and voltage-clamp experiments to measure NH3/NH4+- and MA/MA+-induced intracellular pH (pHi) changes and whole cell currents. Our data showed that in Rhbg oocytes, NH3/NH4+ caused an inward current and decrease in pHi consistent with electrogenic NH4+ transport. These changes were significantly larger than in H2O-injected oocytes. The NH3/NH4+-induced current was not inhibited in the presence of barium or in the absence of Na+. In Rhbg oocytes, MA/MA+ caused an inward current but an increase (rather than a decrease) in pHi. MA/MA+ did not cause any changes in H2O-injected oocytes. The MA/MA+-induced current and pHi increase were saturated at higher concentrations of MA/MA+. Amiloride inhibited MA/MA+-induced current and the increase in pHi in oocytes expressing Rhbg but had no effect on control oocytes. These results indicate that MA/MA+ is transported by Rhbg but differently than NH3/NH4+. The protonated MA+ is likely a direct substrate whose transport resembles that of NH4+. Transport of electroneutral MA is also enhanced by expression of Rhbg.

Abdulnour-Nakhoul, Solange M.; Boulpaep, Emile L.; Rabon, Edd; Schmidt, Eric; Hamm, L. Lee

2010-01-01

442

CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT OF CENTER WITH TOP OF SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

443

Quaternary glaciations in the Northern Hemisphere  

SciTech Connect

This volume presents the final report of Project 24 of the International Geological Correlation Programme. The publication is drawn from the contributions of leading individual scientist as well as from scientific research teams. It reflects the present state of knowledge of the Quaternary Glaciations in the Northern Hemisphere and their correlation in space and time, as well as providing a unique summary of climatic change.

Sibrava, V.; Bowen, D.Q.; Richmond, G.M.

1987-01-01

444

Quaternary phylogeography: the roots of hybrid zones  

Microsoft Academic Search

The older history of hybrid zones is explored through consideration of recent advances in climatology, paleontology and phylogeography\\u000a in the Late Cenozoic, particularly the Quaternary Period with its major climatic cycles. The fossil record shows that these\\u000a ice ages and their nested millennial oscillations caused substantial changes in species distributions and with genetic evidence\\u000a allows deduction of refugia and colonization

Godfrey M. Hewitt

2011-01-01

445

76 FR 46907 - Ammonium Nitrate Security Program  

Federal Register 2010, 2011, 2012, 2013

...Department of Homeland Security/NPPD'' in the subject line...by the minimal security benefit gained...ammonium nitrate in their products...recreational centers, schools, and other entities...while gaps in security of the...

2011-08-03

446

21 CFR 184.1135 - Ammonium bicarbonate.  

Code of Federal Regulations, 2013 CFR

...bicarbonate (NH4 HCO3 , CAS Reg. No. 1066-33-7) is prepared by reacting gaseous carbon dioxide with aqueous ammonia. Crystals of ammonium bicarbonate are precipitated from solution and subsequently washed and dried. (b) The ingredient...

2013-04-01

447

21 CFR 184.1143 - Ammonium sulfate.  

Code of Federal Regulations, 2013 CFR

...sulfate ((NH4 )2 SO4 , CAS Reg. No. 7783-20-2) occurs naturally and consists of colorless or white, odorless crystals or granules. It is prepared by the neutralization of sulfuric acid with ammonium hydroxide. (b) The...

2013-04-01

448

21 CFR 558.340 - Maduramicin ammonium.  

Code of Federal Regulations, 2013 CFR

...PRODUCTS NEW ANIMAL DRUGS FOR USE IN ANIMAL FEEDS Specific New Animal Drugs for Use in Animal Feeds § 558.340 Maduramicin ammonium... (ii) Limitations. For broiler chickens only. Feed continuously as sole ration. Do not...

2013-04-01

449

Decomposition of Four Ammonium Nitrate Propellants.  

National Technical Information Service (NTIS)

The biodegradability of four ammonium nitrate propellants, trimethylammonium nitrate (TMAN), isopropylammonium nitrate (IPAN), triethanolammonium nitrate (TEAN), and hydroxylammonium nitrate (HAN) was assessed in batch and continuous cultures under a vari...

D. L. Kaplan D. J. Emerson P. A. Riley A. M. Kaplan

1983-01-01

450

Granulation of Uranium Trioxide and Ammonium Diuranate.  

National Technical Information Service (NTIS)

The possibilities of the granulation in small laboratory scale of the uranium trioxide and ammonium diuranate were examined. For the uranium trioxide it was stated, that the most advantageous results were obtained by means of the granulation with rotary p...

R. Wlodarski Z. Nowakowska

1975-01-01

451

Pore mutations in ammonium transporter AMT1 with increased electrogenic ammonium transport activity  

Microsoft Academic Search

AMT\\/Mep ammonium transporters mediate high affinity ammonium\\/ammonia uptake in bacteria, fungi, and plants. The Arabidopsis AMT1 proteins mediate uptake of the ionic form of ammonium. AMT transport activity is controlled allosterically via a highly conserved cytosolic C terminus that interacts with neighboring subunits in a trimer. The C terminus is thus capable of modulating the conductivity of the pore. To

D. Loqué; S. I. Mora; S. L. A. Andrade; O. Pantoja; W. B. Frommer

2009-01-01

452

Key Physiology of Anaerobic Ammonium Oxidation  

Microsoft Academic Search

The physiology of anaerobic ammonium oxidizing (anammox) aggregates grown in a sequencing batch reactor was investigated quantitatively. The physiological pH and temperature ranges were 6.7 to 8.3 and 20 to 43°C, respectively. The affinity constants for the substrates ammonium and nitrite were each less than 0.1 mg of nitrogen per liter. The anammox process was completely inhibited by nitrite concentrations

MARC STROUS; J. GIJS KUENEN; MIKE S. M. JETTEN

1999-01-01

453

Effects of urea and a nonionic surfactant on the micellization and counterion binding properties of cetyltrimethyl ammonium bromide and sodium dodecyl sulfate  

Microsoft Academic Search

Micellization characteristics and counterion binding properties of cetyltrimethyl ammonium bromide (CTAB) in presence of urea and a nonionic surfactant polyoxyethylene sorbitan monolaurate (PSML), and of sodium dodecyl sulphate (SDS) in presence of urea as well as of several mixtures of CTAB with a bile salt, sodium cholate (NaC), and sodium chloride have been studied. Both urea and PSML have increased

P. K. Das Gupta; S. P. Moulik

1989-01-01

454

Self-assembly of 3,5-bis(ethoxycarbonyl)pyrazolate anions and ammonium cations of beta-phenylethylamine or homoveratrylamine into hetero-double-stranded helical structures.  

PubMed

Hydrogen-bonded double-stranded hetero-helices are formed when reacting sodium 3,5-bis(ethoxycarbonyl)pyrazolate with beta-phenethylammonium or homoveratrylammonium chloride, in which one of the strands is defined by the ammonium cations and the other one by the pyrazolate anions. PMID:19641775

Reviriego, Felipe; Sanz, Ana; Navarro, Pilar; Latorre, Julio; García-España, Enrique; Liu-Gonzalez, Malva

2009-07-02

455

QUATERNARY GEOLOGICAL FRAMEWORK OF NORTH-HOLLAND AND THE MARKERMEER  

Microsoft Academic Search

Quaternary geological data are presented as a basis for the extensive geohydrological and geotechnical studies performed to investigate possible harmful effects of the Markerwaard reclamation project.

W. E. Westerhoff

456

The influence of ammonium on nitrate reduction in wheat seedlings  

Microsoft Academic Search

Ammonium markedly inhibited nitrate absorption by nitrogenstarved wheat seedlings but did not decrease the proportion of absorbed nitrate that was reduced. Seedlings high in nitrate (absorbed prior to the experimental periods) reduced similar amounts of this nitrate regardless of whether or not ammonium was present and being absorbed during the period of measurement. Ammonium or products of ammonium assimilation did

P. L. Minotti; Doris Craig Williams; W. A. Jackson

1969-01-01

457

Influence of ammonium and nitrate nitrogen on nitrogenase activity of pea plants as affected by light intensity and sugar addition  

Microsoft Academic Search

Summary Addition of ammonium chloride or potassium nitrate to nodulated pea plants resulted in a decrease in acetylene-reducing activity. Both nodule growth and specific activity of the nodules were diminished. Acetylene-reducing activity of isolated bacteroids, treated with EDTA-toluene and supplied with ATP and dithionite, had not decreased after a 3-day treatment of the plants with NH4Cl or KNO3. The effect

F. Houwaard

1980-01-01

458

Tris(2-ethylhexyl) phosphate and tricresyl phosphate as new neutral carriers for organic ammonium ion-selective membrane electrodes  

Microsoft Academic Search

Phosphate esters, such as tris(2-ethylhexyl) phosphate (TEHP) and tricresyl phosphate, can be used as neutral carriers to make organic ammonium ion-selective membrane electrodes. For example, a hexylammonium ion-selective electrode was constructed using TEHP as the carrier and dioctyl phthalate as a membrane solvent in a poly(vinyl chloride) membrane matrix. The electrode exhibited a near-Nernstian response to hexylammonium in the concentration

Takashi Katsu; Dafeng Xu; Kot